Biological applications of bifurcation theory

Biological applications of bifurcation theory provide a framework for understanding the behavior of biological networks modeled as dynamical systems. In the context of a biological system, bifurcation theory describes how small changes in an input parameter can cause a bifurcation or qualitative change in the behavior of the system. The ability to make dramatic change in system output is often essential to organism function, and bifurcations are therefore ubiquitous in biological networks such as the switches of the cell cycle.
Biological networks and dynamical systems.
Biological networks originate from evolution and therefore have less standardized components and potentially more complex interactions than networks designed by humans, such as electrical networks. At the cellular level, components of a network can include a large variety of proteins, many of which differ between organisms. Network interactions occur when one or more proteins affect the function of another through transcription, translation, translocation, or phosphorylation. All these interactions either activate or inhibit the action of the target protein in some way. While humans build networks with some concern for efficiency and simplicity, biological networks are often adapted from others and exhibit redundancy and great complexity. Therefore, it is impossible to predict quantitative behavior of a biological network from knowledge of its organization. Similarly, it is impossible to describe its organization purely from its behavior, though behavior can indicate the presence of certain network motifs.
However, with knowledge of network interactions and a set of parameters for the proteins and protein interactions (usually obtained through empirical research), it is often possible to construct a model of the network as a dynamical system. In general, for n proteins, the dynamical system takes the following form where x is typically protein concentration:
These systems are often very difficult to solve, so modeling of networks as a linear dynamical systems is easier. Linear systems contain no products between "x"s and are always solvable.
They have the following form for all i:
Unfortunately, biological systems are often nonlinear and therefore need nonlinear models.
Input/output motifs.
Despite the great potential complexity and diversity of biological networks, all first-order network behavior generalizes to one of four possible input-output motifs: hyperbolic or Michaelis–Menten, ultra-sensitive, bistable, and bistable irreversible (a bistability where negative and therefore biologically impossible input is needed to return from a state of high output). Examples of each in biological contexts can be found on their respective pages.
Ultrasensitive, bistable, and irreversibly bistable networks all show qualitative change in network behavior around certain parameter values – these are their bifurcation points.
Basic bifurcations in the presence of error.
Nonlinear dynamical systems can be most easily understood with a one-dimensional example system where the change in some quantity "x" (e.g. protein concentration) abundance depends only on itself:
Instead of solving the system analytically, which can be difficult or impossible for many functions, it is often quickest and most informative to take a geometric approach and draw a phase portrait. A phase portrait is a qualitative sketch of the differential equation's behavior that shows equilibrium solutions or fixed points and the vector field on the real line.
Bifurcations describe changes in the stability or existence of fixed points as a control parameter in the system changes. As a very simple explanation of a bifurcation in a dynamical system, consider an object balanced on top of a vertical beam. The mass of the object can be thought of as the control parameter, "r", and the beam's deflection from the vertical axis is the dynamic variable", x". As "r" increases, "x" remains relatively stable. But when the mass reaches a certain point – the bifurcation point – the beam will suddenly buckle, in a direction dependent on minor imperfections in the setup. This is an example of a pitchfork bifurcation. Changes in the control parameter eventually changed the qualitative behavior of the system.
Saddle-node bifurcation.
For a more rigorous example, consider the dynamical system shown in Figure 2, described by the following equation:
formula_8
where "r" is once again the control parameter (labeled ε in Figure 2). The system's fixed points are represented by where the phase portrait curve crosses the x-axis. The stability of a given fixed point can be determined by the direction of flow on the x-axis; for instance, in Figure 2, the green point is unstable (divergent flow), and the red one is stable (convergent flow). At first, when "r" is greater than 0, the system has one stable fixed point and one unstable fixed point. As "r" decreases the fixed points move together, briefly collide into a semi-stable fixed point at "r" = 0, and then cease to exist when "r" < 0.
In this case, because the behavior of the system changes significantly when the control parameter "r" is 0, 0 is a bifurcation point. By tracing the position of the fixed points in Figure 2 as "r" varies, one is able to generate the bifurcation diagram shown in Figure 3.
Other types of bifurcations are also important in dynamical systems, but the saddle-node bifurcation tends to be most important in biology. Real biological systems are subject to small stochastic variations that introduce error terms into the dynamical equations, and this usually leads to more complex bifurcations simplifying into separate saddle nodes and fixed points. Two such examples of "imperfect" bifurcations that can appear in biology are discussed below. Note that the saddle node itself in the presence of error simply translates in the "x-r" plane, with no change in qualitative behavior; this can be proven using the same analysis as presented below.
Imperfect transcritical bifurcation.
A common simple bifurcation is the transcritical bifurcation, given by
formula_9
and the bifurcation diagram in Figure 4 (black curves). The phase diagrams are shown in Figure 5. Tracking the x-intercepts in the phase diagram as "r" changes, there are two fixed point trajectories which intersect at the origin; this is the bifurcation point (intuitively, when the number of x-intercepts in the phase portrait changes). The left fixed point is always unstable, and the right one stable.
Now consider the addition of an error term "h", where 0 < "h" « 1. That is,
formula_10
The error term translates all the phase portraits vertically, downward if "h" is positive. In the left half of Figure 6 ("x" < 0), the black, red, and green fixed points are semistable, unstable, and stable, respectively. This is mirrored by the magenta, black, and blue points on the right half ("x" > 0). Each of these halves thus behaves like a saddle-node bifurcation; in other words, the imperfect transcritical bifurcation can be approximated by two saddle-node bifurcations when close to the critical points, as evident in the red curves of Figure 4.
Linear stability analysis.
Besides observing the flow in the phase diagrams, it is also possible to demonstrate the stability of various fixed points using linear stability analysis. First, find the fixed points in the phase portrait by setting the bifurcation equation to 0:
formula_11
Using the quadratic formula to find the fixed points "x*":
formula_12
where in the last step the approximation 4"h" « "r" 2 has been used, which is reasonable for studying fixed points well past the bifurcation point, such as the light blue and green curves in Figure 6. Simplifying further,
formula_13
Next, determine whether the phase portrait curve is increasing or decreasing at the fixed points, which can be assessed by plugging "x"* into the first derivative of the bifurcation equation.
formula_14
The results are complicated by the fact that "r" can be both positive and negative; nonetheless, the conclusions are the same as before regarding the stability of each fixed point. This comes as no surprise, since the first derivative contains the same information as the phase diagram flow analysis. The colors in the above solution correspond to the arrows in Figure 6.
Imperfect pitchfork bifurcation.
The buckling beam example from earlier is an example of a pitchfork bifurcation (perhaps more appropriately dubbed a "trifurcation"). The "ideal" pitchfork is shown on the left of Figure 7, given by
formula_15
and "r" = 0 is where the bifurcation occurs, represented by the black dot at the origin of Figure 8. As "r" increases past 0, the black dot splits into three trajectories: the blue stable fixed point that moves right, the red stable point that moves left, and a third unstable point that stays at the origin. The blue and red are solid lines in Figure 7 (left), while the black unstable trajectory is the dotted portion along the positive x-axis.
As before, consider an error term "h", where 0 < "h" « 1, i.e.
formula_16
Once again, the phase portraits are translated upward an infinitesimal amount, as shown in Figure 9.Tracking the x-intercepts in the phase diagram as r changes yields the fixed points, which recapitulate the qualitative result from Figure 7 (right). More specifically, the blue fixed point from Figure 9 corresponds to the upper trajectory in Figure 7 (right); the green fixed point is the dotted trajectory; and the red fixed point is the bottommost trajectory. Thus, in the imperfect case ("h" ≠ 0), the pitchfork bifurcation simplifies into a single stable fixed point coupled with a saddle-node bifurcation.
A linear stability analysis can also be performed here, except using the generalized solution for a cubic equation instead of quadratic. The process is the same: 1) set the differential equation to zero and find the analytical form of the fixed points "x*", 2) plug each "x*" into the first derivative formula_17, then 3) evaluate stability based on whether formula_18 is positive or negative.
Multistability.
Combined saddle-node bifurcations in a system can generate multistability. Bistability (a special case of multistability) is an important property in many biological systems, often the result of network architecture containing a mix of positive feedback interactions and ultra-sensitive elements. Bistable systems are hysteretic, i.e. the state of the system depends on the history of inputs, which can be crucial for switch-like control of cellular processes. For instance, this is important in contexts where a cell decides whether to commit to a particular pathway; a non-hysteretic response might switch the system on-and-off rapidly when subject to random thermal fluctuations close to the activation threshold, which can be resource-inefficient.
Specific examples in biology.
Networks with bifurcation in their dynamics control many important transitions in the cell cycle. The G1/S, G2/M, and Metaphase–Anaphase transitions all act as biochemical switches in the cell cycle. For instance, egg extracts of Xenopus laevis are driven in and out of mitosis irreversibly by positive feedback in the phosphorylation of Cdc2, a cyclin-dependent kinase.
In population ecology, the dynamics of food web interactions networks can exhibit Hopf bifurcations. For instance, in an aquatic system consisting of a primary producer, a mineral resource, and an herbivore, researchers found that patterns of equilibrium, cycling, and extinction of populations could be qualitatively described with a simple nonlinear model with a Hopf Bifurcation.
Galactose utilization in budding yeast (S. cerevisiae) is measurable through GFP expression induced by the GAL promoter as a function of changing galactose concentrations. The system exhibits bistable switching between induced and non-induced states.
Similarly, lactose utilization in E. coli as a function of thio-methylgalactoside (a lactose analogue) concentration measured by a GFP-expressing lac promoter exhibits bistability and hysteresis (Figure 10, left and right respectively).


Progress indicator

A progress indicator is an element of a command-line interface, a textual user interface, or a graphical user interface that is intended to inform the user that an operation is in progress, to reassure that the system is not hung or waiting for user input,
and often to provide the user with an estimate of how far through a task the system has progressed.


Saint Petersburg State University of Aerospace Instrumentation

The Saint Petersburg State University of Aerospace Instrumentation () is a university with 13 faculties in Saint Petersburg, Russia. Faculties are devoted to innovation management, aerospace engineering, electronic engineering, energy development, computer science, telecommunication, humanities, military science, economics, jurisprudence and special faculties for distance education and recently acquired colleges.
University has several buildings and campuses, two of them located near to Chesme Church. Main building is located on the bank of the Moyka River, on the opposite bank of the river stands the building of Moika Palace. One campus of SUAI is situated in Ivangorod, near the border with Estonia.
There are students from many countries through international educational programs. Total quantity of students is more than 10 thousand.
History.
In 1941 the institute was founded as the "Leningrad Institute of Aviation" ().
In 1945 the institute was reorganized as the "Leningrad Institute of Aviation Instrumentation" ().
In 1992 the Leningrad Institute of Aerospace Instrumentation passed the state accreditation and has received a new status – Saint-Petersburg State Academy of Aerospace Instrumentation ().
In 1998 the Saint-Petersburg State Academy of Aerospace Instrumentation passed the state accreditation and has received a new status – Saint-Petersburg State University of Aerospace Instrumentation (abbreviation SUAI) ().
In 2007 SUAI acquired two colleges, whose main specializations were computer science, automatics and electronics. They were united into new faculty in 2009. Both of them were established in 1930.
International Partners.
Worldwide
In Argentine
In Belgium
In Bulgaria
In Canada
In China
In Europe
In Finland and Russia
In France
In Hungary
In Germany
In Israel
In Italy
In Korea
In The Netherlands
In Poland
In Russia
In Spain
In Sweden
In Taiwan
In USA
and others.
Plagiarism cases in University academical staff.
Russian civic activity site dissernet.org has published an investigation which demonstrates a significant amount of plagiarism in the Doktor Nauk degree thesis of the current head of SUAI Prof. Antokhina.


Screw-cutting lathe

A screw-cutting lathe is a machine (specifically, a lathe) capable of cutting very accurate screw threads via single-point screw-cutting, which is the process of guiding the linear motion of the tool bit in a precisely known ratio to the rotating motion of the workpiece. This is accomplished by gearing the leadscrew (which drives the tool bit's movement) to the spindle with a certain gear ratio for each thread pitch. Every degree of spindle rotation is matched by a certain distance of linear tool travel, depending on the desired thread pitch (English or metric, fine or coarse, etc.).
The name "screw-cutting lathe" carries a taxonomic qualification on its use—it is a term of historical classification rather than one of current commercial machine tool terminology. Early lathes, many centuries ago, were not adapted to screw-cutting. Later, from the Late Middle Ages until the early nineteenth century, some lathes were distinguishable as "screw-cutting lathes" because of the screw-cutting ability specially built into them. Since then, most metalworking lathes have this ability built in, but they are not called "screw-cutting lathes" in modern taxonomy.
History.
The screw has been known for millennia. Archimedes devised the water screw, a system for raising water. Screws as mechanical fasteners date to the first century BC. Although screws were tremendously useful, the difficulty in making them prevented any widespread adoption.
Early wooden screws.
The earliest screws tended to be made of wood, and they were whittled by hand, with or without the help of turning on a lathe with hand-controlled turning tools (chisels, knives, gouges), as accurately as the whittler could manage. It is likely that sometimes the wood blanks that they started from were tree branches (or juvenile trunks) that had been shaped by a vine wrapped helically around them while they grew. (In fact, various Romance words for "screw" come from the word root referring to vines.) Walking sticks twisted by vines show how suggestive such sticks are of a screw.
Early metal screws.
Early machine screws of metal, and early wood screws [screws made of metal for use in wood], were made by hand, with files used to cut the threads. One method for making fairly accurate threads was to score a rod using an inclined knife with a wrap half way around the rod, the knife being precisely angled for the proper pitch. This was one of the methods Maudslay used to make his early leadscrews. This made the screw slow and expensive to make, and its quality highly dependent on the skill of the maker. A process for automating the manufacture of screws and improving the accuracy and consistency of the thread was needed.
Earliest lathes with machine-guided toolpath for screw-cutting.
Lathes have been around since ancient times. Adapting them to screw-cutting is an obvious choice, but the problem of how to guide the cutting tool through the correct path was an obstacle for many centuries. Not until the late Middle Ages and early modern period did breakthroughs occur in this area; the earliest of which evidence exists today happened in the 15th century and is documented in the "". It incorporates slide rests and a leadscrew. Roughly contemporarily, Leonardo da Vinci drew sketches showing various screw-cutting lathes and machines, one with two leadscrews. Leonardo also shows change-gears in some of these sketches.
In the succeeding three centuries, many other designs followed, especially among ornamental turners and clockmakers. These included various important concepts and impressive cleverness, but few were significantly accurate and practical to use. For example, Woodbury discusses Jacques Besson and others. They made impressive contributions to turning, but the context in which they tended to work (turning as a fine art for rich people) did not channel their contributions toward industrial uses.
Henry Hindley designed and constructed a screw-cutting lathe circa 1739. It featured a plate guiding the tool and power supplied by a hand-cranked series of gears. By changing the gears, he could cut screws with different pitch. Removing a gear permitted him to make left-handed threads.
Modern screw-cutting lathes (late 18th to early 19th centuries).
The first truly modern screw-cutting lathe was likely constructed by Jesse Ramsden in 1775. His device included a leadscrew, slide rest, and change gear mechanism. These form the elements of a modern (non-CNC) lathe and are in use to this day. Ramsden was able to use his first screw-cutting lathe to make even more accurate lathes. With these, he was able to make an exceptionally accurate dividing engine and in turn, some of the finest astronomical, surveying, and navigational instruments of the 18th century.
Others followed. Examples were a French mechanic surnamed Senot, who in 1795 created a screw-cutting lathe capable of industrial-level production, and David Wilkinson of Rhode Island, who employed a slide rest in 1798. However, these inventors were soon overshadowed by Henry Maudslay, who in 1800 created a screw-cutting lathe that is frequently cited as the first. Clearly, his was not the first; however, his did become the best known, spreading to the rest of the world the winning combination of leadscrew, slide-rest, and change gears, in an arrangement practical to use and robust enough for cutting metal. These late-18th-century screw-cutting lathes represented the breakthrough development of the technology. They permitted the large-scale, industrial production of screws that were interchangeable. Standardization of threadforms (including thread angle, pitches, major diameters, pitch diameters, etc.) began immediately on the intra-company level, and by the end of the 19th century, it had been carried to the international level (although pluralities of standards still exist).
In the late 19th century Henry Augustus Rowland found a need for very high precision screws in cutting diffraction gratings, so he developed a technique for making them.
Present day.
Until the early 19th century, the notion of a screw-cutting lathe stood in contrast to the notion of a plain lathe, which lacked the parts needed to guide the cutting tool in the precise path needed to produce an accurate thread. Since the early 19th century, it has been common practice to build these parts into any general-purpose metalworking lathe; thus, the distinction between "plain lathe" and "screw-cutting lathe" does not apply to the classification of modern lathes. Instead, there are other categories, some of which bundle single-point screw-cutting capability among other capabilities (for example, regular lathes, toolroom lathes, and CNC lathes), and some of which omit single-point screw-cutting capability as irrelevant to the machines' intended purposes (for example, speed lathes and turret lathes).
Today the threads of threaded fasteners (such as machine screws, wood screws, wallboard screws, and sheetmetal screws) are usually not cut via single-point screw-cutting; instead most are generated by other, faster processes, such as thread forming and rolling and cutting with die heads. The latter processes are the ones employed in modern screw machines. These machines, although they are lathes specialized for making screws, are not screw-cutting lathes in the sense of employing single-point screw-cutting.


.22 Long Rifle

The .22 Long Rifle or simply .22 LR (metric designation: 5.6×15mmR) is a long-established variety of .22 caliber rimfire ammunition originating from the United States. It is used in a wide range of rifles, pistols, revolvers, smoothbore shotguns, and submachine guns.
In terms of units sold it is by far the most common ammunition in the world today. Common uses include hunting and shooting sports. The .22 Long Rifle is effective at short ranges and has little recoil making it ideal for training.
History.
American cartridge manufacturer Union Metallic Cartridge Company most likely introduced the .22 Long Rifle cartridge as early as 1884. The round owes its origin to the .22 BB Cap of 1845 and the .22 Short of 1857. It combined the case of the .22 Long of 1871 with a bullet, giving it a longer overall length, a higher muzzle velocity and superior performance as a hunting and target round, rendering the .22 Extra Long cartridges obsolete. The .22 LR uses a heeled bullet, which means that the bullet is the same diameter as the case, and has a narrower "heel" portion that fits in the case. It is one of the few cartridges that are accepted by a large variety of rifles and handguns.
Popularity in the United States.
The .22 LR cartridge is popular with both novice shooters and experts. Its minimal recoil and relatively low noise make it an ideal cartridge for recreational shooting, small-game hunting, and pest control. .22 LR cadet rifles are commonly used by military cadets and others for basic firearms and marksmanship training. It is used by the Boy Scouts of America for the rifle shooting merit badge.
The low recoil of the cartridge makes it ideal for introductory firearms courses. Novice shooters can be surprised or frightened by the noise and recoil of more powerful rounds. Beginners shooting firearms beyond their comfort level frequently develop a habit of flinching in an attempt to counter anticipated recoil. The resulting habit impedes correct posture and follow-through at the most critical phase of the shot and is difficult to correct. With high recoil eliminated, other errors in marksmanship technique are easier to identify and correct.
Available for this round are AR-15 upper receivers and M1911 slide assemblies. Many handgun manufacturers have an upper pistol conversion kit to make it shoot .22 LR ammunition. These conversions allow shooters to practice inexpensively while retaining the handling characteristics of their chosen firearms (with reduced recoil and muzzle blast). Additionally, .22 LR cartridge conversion kits allow practice at indoor ranges which prohibit high-power firearms. Owners of guns that use gas systems, such as AR-15 sport style rifles, normally avoid firing non-jacketed .22 LR cartridge ammunition, as the use of unjacketed ammunition may cause lead-fouling of the gas-port inside the barrel and costly gunsmithing procedures. This can usually be mitigated by swapping the conversion kit for the standard bolt carrier group, and firing several full-powered rounds to clear the gas port and tube of any accumulated lead fouling. While not 100% effective, the extremely hot incandescent gasses produced by centerfire rifle ammunition will help to clear any lead fouling from the .22 LR ammunition.
A wide variety of .22 LR ammunition is available commercially, and the available ammunition varies widely both in price and performance. Bullet weights among commercially available ammunition range from , and velocities vary from . .22 LR is the least costly cartridge ammunition available. Promotional loads for plinking can be purchased in bulk for significantly less cost than precision target rounds. The low cost of ammunition has a substantial effect on the popularity of the .22 LR. For this reason, rimfire cartridges are commonly used for target practice.
.22 LR cartridges are commonly packaged in boxes of 50 or 100 rounds, and are often sold by the 'brick', a carton containing either 10 boxes of 50 rounds or loose cartridges totaling 500 rounds, or the 'case' containing 10 bricks totaling 5,000 rounds. Annual production is estimated by some at 2–2.5 billion rounds. The NSSF estimates that a large percentage of the US production of 10 billion cartridges is composed of .22 LR. Despite the high production figures there have occasionally been shortages of .22 LR cartridge in the contiguous United States, most notably during the U.S. ammunition shortage of the late 2000s and early 2010s.
Performance.
The .22 LR is effective to , though practical ranges tend to be less. After 150 yd, the ballistics of the round are such that it will be difficult to compensate for the large "drop". The relatively short effective range, low report, and light recoil have made it a favorite for use as a target-practice cartridge. The accuracy of the cartridge is good, but not exceptional; various cartridges are capable of the same or better accuracy. A contributing factor in rifles is the transition of even a high-velocity cartridge projectile from supersonic to subsonic within . As the bullet slows, the shock wave caused by supersonic travel overtakes the bullet and can disrupt its flight path, causing minor but measurable inaccuracies.
When zeroed for , the arc-trajectory of the standard high-velocity .22 LR with a bullet has a rise at , and a drop at . A .22 LR rifle needs to be zeroed for to avoid overshooting small animals like squirrels at intermediate distances.
As a hunting cartridge, rimfires are mainly used to kill small game up to the size of coyotes. Although proper shot placement can kill larger animals such as deer or hog, it is not recommended because its low power may not guarantee a humane kill. In 2013, an elephant was killed by multiple shots from a .22 LR rifle.
Because a .22 LR bullet is less powerful than larger cartridges, its danger to humans is often underestimated. In fact, a .22 LR bullet is easily capable of killing or injuring humans. Even after flying , a .22 bullet is still traveling about . Ricochets are more common in .22 LR projectiles than for more powerful cartridges as the combination of unjacketed lead and moderate velocities allows the projectile to deflectnot penetrate or disintegratewhen hitting hard objects at a glancing angle. A .22 LR bullet can ricochet off the surface of water at a low angle of aim. Severe injury may result to a person or object in the line of fire on the opposite shore, several hundred yards away. A .22 LR bullet is capable of traveling , which is more than .
Rimfire bullets are generally either plain lead with a wax coating (for standard-velocity loads) or plated with copper or gilding metal (for high-velocity or hyper-velocity loads). The thin copper layer on plated bullet functions as a lubricant reducing friction between the bullet and the barrel, thus reducing barrel wear. Plating also prevents oxidation of the lead bullet. Lead tends to oxidize if stored for long periods. On a plain lead bullet, oxide on the bullet's surface can increase its diameter enough to either prevent insertion of the cartridge into the chamber, or – with high velocity rounds – cause dangerously high pressures in the barrel, potentially rupturing the cartridge case and injuring the shooter; for that reason, standard and subsonic cartridges usually use a wax lubricant on lead bullets.
Variants.
The variety of .22 LR loads are often divided into four distinct categories, based on nominal velocity:
Subsonic.
Subsonic rounds have a muzzle velocity of less than the speed of sound (about ). These rounds are sometimes equipped with extra-heavy bullets of to improve the terminal ballistics of the slower projectile. Conversely, these rounds may contain little more than a primer and an extra-light bullet.
Subsonic rounds are favored by some shooters due to slightly superior accuracy and reduction in noise. Supersonic rounds produce a loud crack which can scare away animals when hunting. Accuracy is reportedly improved with subsonic rounds because a supersonic bullet (or projectile) that slows from supersonic to subsonic speed undergoes drastic aerodynamic changes in this transonic zone that might adversely affect the stability and accuracy of the bullet.
Because the speed of sound in air at is about , the subsonic round's muzzle velocity is slightly below the speed of sound under many hunting conditions. However, under cold air conditions at , the speed of sound drops to , approximately muzzle velocity. Hence, a "subsonic" round used below this temperature may be supersonic, and during the transition from supersonic to subsonic velocity, it may become unstable, reducing accuracy. To counteract this, some cartridge manufacturers have lowered the speed of their subsonic ammunition to or less.
Various combinations of subsonic rounds and semiautomatic .22 LR firearms result in unreliable cycling of the firearms' actions, as the result of insufficient recoil energy. Some subsonic rounds use heavier bullets (achieving lower velocities) to ensure, as a result of increased bullet mass, that enough energy is produced to cycle common blow-back actions. As an example, the Aguila .22 LR SSS "Sniper SubSonic" round, has a bullet on a .22 short case, providing the cartridge the same overall dimensions as a .22 long rifle round. However, other problems may be encountered: the heavier and longer bullet of the Aguila cartridge requires a faster barrel twist (by the Greenhill formula) to ensure the bullet remains stable in flight.
Two performance classes of .22 rimfire subsonic rounds exist. Some subsonic rounds, such as various .22 short and .22 long "CB" rounds, give about velocity with a bullet providing relatively low impact energy (41 J at muzzle). These may not use any, or only small amounts of gunpowder, and have the characteristics of rounds intended only for indoor training or target practice rather than hunting. Where these are in .22 LR form, it is only to aid feeding in firearms designed for the cartridge, rather than older .22 CB shooting gallery rifles. The Aguila SSS gives about velocity with a 60-gr bullet offering energy (163 Joules) equivalent to many high velocity .22 long rifle rounds using standard 40-gr bullets. Other heavy-bullet subsonic rounds give similar performance, and are intended for hunting of small game, or control of dangerous animals, while avoiding excessive noise.
Standard velocity.
The velocity of standard-velocity .22 LR rounds varies between manufacturers. Some standard velocity ammo may be slightly supersonic-around , other ammo such as CCI Standard Velocity .22 LR ammunition is rated at . Most standard velocity ammo has a bullet weight of . Standard-velocity cartridges generate near or slightly supersonic velocities. These rounds generally do not develop these velocities in handguns because their short barrels do not take full advantage of the slower burning powder.
High velocity.
The .22 long rifle round was originally loaded with black powder. The first smokeless powder loads were intended to match the standard velocity of the original black-powder rounds. Smokeless powder is more efficient than black powder, and the cartridge cases could hold more powder. Smokeless powder loads, called "high speed" or "high velocity", were offered by the major ammunition makers, giving a typical velocity increase of 8% ( to ) while still using the standard solid or hollow-point lead bullet.
Hyper-velocity.
Many .22 LR cartridges use bullets lighter than the standard , fired at even higher velocities. Hyper-velocity bullets usually weigh around and can have a muzzle velocity of . This higher velocity is partially due to the use of lighter bullets.
The CCI Stinger was the first hyper-velocity .22 LR cartridge, and provided a significant increase in velocity and energy over standard rimfire rounds. The Stinger case is longer than that of the long rifle; about "versus" for the long rifle, but the plated hollow point bullet is lighter and shorter at , giving the same overall length as the long rifle cartridge. This longer case can cause ejection problems in some guns. A powder with a slower burning rate is used to make the most use of the length of a rifle barrel. Most .22 long rifle powders increase velocity up to about of barrel. The powder used in the Stinger increases velocity up to the longest .22 barrel length tested by the NRA, .
Later hyper-velocity rounds were introduced by other makers, based on the long rifle case with lighter bullets in the 30-gr weight range and slow-burning rifle powder loadings. The overall length of many of these cartridges was less than the overall length of the standard 40-gr bullet long rifle cartridge. One example is the Remington Viper; another is the Federal Spitfire.
The CCI Velocitor hyper-velocity round uses the standard long rifle case size and a standard weight bullet of proprietary hollow-point design to augment expansion and trauma. This cartridge has a muzzle velocity of and matches the overall length of the standard long rifle cartridge.
Shot cartridges.
Special .22 LR caliber shot cartridges, usually loaded with No. 12 shot, have also been made. These are often called "snake shot," "bird shot" and "rat-shot" due to their use in very short range pest control. Such rounds have either a longer brass case that is crimped closed, or a translucent plastic "bullet" that contains the shot and shatters upon firing. In specially made .22-bore shotguns, the shot shells can be used for short-range skeet shooting and trap shooting at special, scaled-down, clay targets.
Full metal jacket.
During World War II, a full metal jacket bullet version of the .22 LR was developed as the T-42 for the silenced High Standard HDM pistol. The US Army Air Corps procured the Savage Model 24 .22 LR/.410 combination gun as an air crew survival weapon included in the E series of survival and sustenance kits, primarily to forage for game for food. The .22 LR full metal jacket bullet ammunition was issued with these firearms for military use to comply with treaty restrictions on expanding bullets.
The 1961 Army/Air Force Technical Manual/Order on ammunition lists three types of rimfire CARTRIDGE, CALIBER .22: Ball, Long Rifle:
The first type specifies standard or target velocity .22 LR while the second is common high velocity commercial ammo. While these soft lead round nose bullet types were suitable for training or target practice, they are not legal for use in a war zone. Since .22 LR air crew survival weapons would probably be used in a war zone and could be used for defense, the M24 round is loaded with a hard lead-antimony alloy core bullet with a gilding metal jacket.
Tracer.
Tracer ammunition is also available in rimfire.
Cartridge construction.
The traditional .22 rimfire cartridges (BB, CB, short, long, extra long, and long rifle) differ in construction from more modern cartridges in the way the bullet is constructed and held in the case. Bullets for traditional .22 rimfires are the same outside diameter as the case but are constructed with a narrower cupped "heel" on the base of the bullet which is inserted into the case. The case mouth is then crimped around the heel, leaving exposed the majority of the bullet bearing surface that contacts the barrel of the gun. The bearing surface of .22 rimfire bullets is often lubricated and the surface is exposed to contamination. This was a common design in the early black powder cartridge era.
In later cartridges including the .22 WRF and .22 WMR rimfires and modern centerfires, the bullet body is a uniform diameter and the bearing surface is inserted completely within the neck of the cartridge case, held in place by tension from the case neck around the bullet bearing surface (in some cartridges the case mouth maybe also be crimped into a cannelure (groove) in the bullet). The heeled bullet cartridge is considered weaker than the uniform diameter bullet cartridge which encloses the bearing surface of the bullet within the cartridge neck. Overall reliability of heeled bullet rimfire ammunition is high, but it is lower than the reliability of most centerfire ammunition.
Cartridge length.
The .22 LR uses a straight-walled case. Depending upon the type and the feed mechanism employed, a firearm that is chambered for .22 LR may also be able to safely chamber and fire the following shorter rimfire cartridges:
The .22 Long Rifle may also be used in firearms chambered for the obsolete .22 Extra Long.
Usage.
Today, rimfire rounds are mainly used for hunting small pests, for sports shooting, for plinking, and for inexpensive training. The .22 LR is the choice for several shooting events: biathlon, bullseye, plus divisions of benchrest shooting, metallic silhouette and pin shooting, most high school, collegiate, Boy Scouts of America, Project Appleseed, 4H shooting events, and many others. It is also used in the precision Rifle and Pistol shooting events at the Olympic Games. Good quality rimfire ammunition can be quite accurate. The main advantages are low cost, low recoil, low noise and high accuracy-to-cost ratio. The main disadvantage is its low power; it is better suited for use on small game and other small animals.
As a defensive cartridge, it is considered inadequate by many, though the small size allows very lightweight, easily concealable handguns which can be carried in circumstances where anything larger would be impractical. Despite their limitations, people can use .22 LR pistols and rifles for defense, and are common simply because they are prevalent, inexpensive, and widely available.
Most semi-automatic rifles firing .22 LR cartridges will often only work properly when firing standard or high velocity rimfire ammunition, as the low recoil of subsonic rounds is insufficient to cycle the weapon's action. Rifles with manual actions do not have this problem. Due to the low bolt thrust of the .22 LR cartridge, most self-loading firearms chambered for the cartridge use the direct blowback operation system.
The tiny case of the .22 LR and the subsonic velocities (when using subsonic ammunition) make it well suited for use with a firearm suppressor (also known as silencers or sound moderators). The low volume of powder gases means that .22 LR suppressors are often no larger than a bull barrel; the Ruger 10/22 and Ruger MK II are common choices, because of their reliability and low cost, and the resulting product is often nearly indistinguishable from a bull barrel model (although weighing far less). Where firearm suppressors are only minimally restricted, a .22 LR firearm with a suppressor is often favored for plinking, as it does not require hearing protection or disturb the neighbors. Local government agencies sometimes use suppressed rimfire weapons for animal control, since dangerous animals or pests can be dispatched in populated areas without causing undue alarm.
The .22 LR has also seen limited usage by police and military snipers. Its main advantage in this role is its low noise, but it is usually limited to urban operations because of its short range.<ref name="Ruger 10/22 Suppressed Sniper Rifle"></ref>
The Israeli military used a suppressed .22 LR rifle in the 1990s for riot control and to "eliminate disturbing dogs prior to operations", though it is now used less often as it has been shown to be more lethal than previously suspected. Some other examples include the use of suppressed High Standard HDM pistols by the American OSS, which was the predecessor organization of the CIA. Francis Gary Powers was issued a suppressed High Standard for the flight in which he was shot down. Suppressed Ruger MK II pistols were used by the US Navy SEALs in the 1990s.
Cartridge dimensions.
.22 long rifle maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).
The common rifling twist rate for this cartridge is 406 mm (1:16 in), six grooves, land width = 2.16 mm, Ø lands = 5.38 mm, Ø grooves = 5.58 mm.
According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings the .22 long rifle can handle up to Pmax piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers.
Because the .22 long rifle round commonly uses a heeled lead or lightly plated bullet, the nominal bullet diameter is larger than the nominal bore diameter to prevent excessive lead fouling that can occur when shooting lead bullets that are the same or slightly smaller than the groove diameter. SAAMI specifies a nominal bullet diameter of 0.2255 with a tolerance of -0.004, while the specified bore diameter is 0.222. In practice, 0.224 or slightly larger bullets are common, with barrel groove diameters commonly around 0.223.
Muzzle velocity (nominal).
Note: actual velocities are dependent on many factors, such as barrel length of a given firearm and manufacturer of a given batch of ammunition, and will vary widely in practice. The above velocities are typical.


IEC TC 25

IEC Technical Committee 25, "Quantities and units, and their letter symbols", was established in 1935. It is one of the technical committees of the International Electrotechnical Commission (IEC).
It merged with TC 24 and as a committee with "horizontal" responsibilities (i.e. covering matters of a wide-ranging nature and applicable by many “vertical” or product-oriented committees), it is in charge of all questions concerning the SI.
Among other standards it is responsible for parts 6, 13, 14, 15, 16, 17 of ISO/IEC 80000.


Nikon Z-mount

Nikon Z-mount (stylised as ℤ) is an interchangeable lens mount developed by Nikon for its full-frame mirrorless digital cameras. In late 2018, Nikon released two cameras that use this mount, the Nikon Z 7 and the Nikon Z 6. In late 2019, Nikon announced their first APS-C sensor size Z-mount camera, the Nikon Z 50. In October 2020, Nikon announced the Nikon Z 6II and Nikon Z 7II, which succeed the Z 6 and Z 7, respectively.
Nikon SLR cameras have used the Nikon F-mount, with its 44 mm diameter, since 1959. The FTZ lens adapter allows many F-mount lenses to be used on Z-mount cameras. The FTZ allows AF-S, AF-P and AF-I lenses to autofocus on Z-mount cameras, while retaining metering and EXIF data with the older screw-drive AF and AF-D lenses. Z cameras support metering as well as in-body image stabilization (IBIS) with manual focus lenses.
The 55 mm diameter of the Nikon Z-mount is the largest in current use. It is much larger than the F-mount, the 46.1 mm Sony E that is used by all Sony mirrorless cameras, including those with a full-frame sensor but only slightly larger than the 54 mm of both the Canon EF and Canon RF mounts. It is also slightly larger than the new 51.6 mm diameter full-frame mirrorless L-mount from Leica, Panasonic and Sigma. The Z-mount has also a very short flange distance of 16 mm, which is shorter than Canon RF and Sony E.
The introduction of the Z-mount also saw the re-introduction of the Noct brand, used to describe a forthcoming 58 mm S Noct lens with an ultra wide maximum aperture. This is one of the new lenses that Nikon will be developing, up to 2021, according to its roadmap published in late 2018.
Image circle.
Nikon Z-mount lenses cover the Nikon FX format, except for DX designated lenses, which cover the 24×16 mm area of the Nikon DX format. FX Z cameras switch to a DX crop mode when a DX lens is attached.
Z-mount lenses.
Nikon uses these designations in their Z mount lens names:


Marlin Model 20

The Marlin No. 20 is a slide-action .22 caliber rifle with an octagonal barrel and tubular magazine, bearing patents of August 12, 1890 through November 29, 1904, produced by the Marlin Firearms Co. of New Haven, Connecticut.
It is not the same as the Glenfield Model 20 (Marlin 780). The Model 20 is a bolt-action rifle that fires primarily the .22LR rimfire cartridge, but also the .22 short, and the obsolete .22 long (all rimfire cartridges, and can all be fired in the same gun). Produced by the Marlin Firearms Company of North Haven, Connecticut, it was in production from 1960 to 1966.
Uses.
The Model 20 is well-suited for small-game hunting and vermin control, as well as a target practice gun.


Petrocephalus bane

Petrocephalus bane is a species of elephantfish native to Africa where it occurs in the basins of the Nile, Bénoué and Volta rivers and the Chad Basin. It prefers relatively still waters of lakes, irrigation canals and lagoons. This species can reach a length of SL. It can also be found in the aquarium trade.


Franck Goldnadel

Franck Goldnadel (born 14 August 1969) is a French public servant and former director of Paris-Charles de Gaulle Airport.
Biography.
Graduating from the "École nationale de l'aviation civile" (French civil aviation academy, promotion 1990), he started his career in 1993 at the air transport department of ENAC where he was working on the Airbus training programs. From 1994 to 1997, he was commercial manager of "Alyzia Airport Services", subsidiary of "Aéroports de Paris" for ground handling services.
He joins "Aéroports de Paris" in 1997 where he would become director of Paris-Orly Airport and then head of the Terminal 2 at Paris-Charles de Gaulle Airport. On 1 March 2011 Goldnadel was appointed director of Charles de Gaulle Airport. He left his position in February 2018, replaced by Marc Houalla.


Henry Gantt

Henry Laurence Gantt (; May 20, 1861 – November 23, 1919) was an American mechanical engineer and management consultant who is best known for his work in the development of scientific management. He created the Gantt chart in the 1910s.
Gantt charts were employed on major infrastructure projects including the Hoover Dam and Interstate highway system and continue to be an important tool in project management and program management.
Biography.
Early life, education and family.
Gantt was born to a slave-owning plantation family in Calvert County, Maryland at the outbreak of the American Civil War. When the war ended the family lost their slaves and land, and moved to Baltimore.
He graduated from McDonogh School in 1878 and from Johns Hopkins University in 1880, and then returned to the McDonogh School to teach for three years. He subsequently received a Masters of Engineering degree in mechanical engineering from the Stevens Institute of Technology in New Jersey. Henry Gantt married Mary E. Snow of Fitchburg, Massachusetts on 29 Nov 1899.
Career.
In 1884, Gantt began working as a draughtsman at the iron foundry and machine-shop Poole & Hunt in Baltimore. In 1887 he joined Frederick W. Taylor in applying scientific management principles to the work at Midvale Steel and Bethlehem Steel, working there with Taylor until 1893.
In his later career as an industrial consultant and following the invention of the Gantt chart, he designed the 'task and bonus' system of wage payment and additional measurement methods worker efficiency and productivity. In 1908-09 he undertook projects at Joseph Bancroft & Sons Company and Williams & Wilkins.
In 1916, influenced by Thorsten Veblen Gantt set up the "New Machine", an association which sought to apply the criteria of industrial efficiency to the political process. With the Marxist Walter Polakov he led a breakaway from the 1916 ASME conference to call for socialising industrial production under the control of managers incorporating Polakov's analysis of inefficiency in the industrial context.
Henry Gantt is listed under Stevens Institute of Technology alumni. The American Society of Mechanical Engineers (ASME) published his biography in 1934 and awards an annual medal in honor of Henry Laurence Gantt.
Work.
Henry Gantt's legacy to project management is the following:
Gantt charts.
Gantt created many different types of charts. He designed his charts so that foremen or other supervisors could quickly know whether production was on schedule, ahead of schedule, or behind schedule. Modern project management software includes this critical function.
Gantt (1903) describes two types of "balances":
Gantt gives an example with orders that will require many days to complete. The daily balance has rows for each day and columns for each part or each operation. At the top of each column is the amount needed. The amount entered in the appropriate cell is the number of parts done each day and the cumulative total for that part. Heavy horizontal lines indicate the starting date and the date that the order should be done. According to Gantt, the graphical daily balance is "a method of scheduling and recording work". In this 1903 article, Gantt also describes the use of:
"Work, Wages, and Profits", 1916.
In his 1916 book "Work, Wages, and Profits" Gantt explicitly discusses scheduling, especially in the job shop environment. He proposes giving to the foreman each day an "order of work" that is an ordered list of jobs to be done that day. Moreover, he discusses the need to coordinate activities to avoid "interferences". However, he also warns that the most elegant schedules created by planning offices are useless if they are ignored, a situation that he observed.
"Organizing for Work," 1919.
In his 1919 book "Organizing for Work" Gantt gives two principles for his charts:
Gantt shows a progress chart that indicates for each month of the year, using a thin horizontal line, the number of items produced during that month. In addition, a thick horizontal line indicates the number of items produced during the year. Each row in the chart corresponds to an order for parts from a specific contractor, and each row indicates the starting month and ending month of the deliveries. It is the closest thing to the Gantt charts typically used today in scheduling systems, though it is at a higher level than machine scheduling.
Gantt's machine record chart and man record chart are quite similar, though they show both the actual working time for each day and the cumulative working time for a week. Each row of the chart corresponds to an individual machine or operator. These charts do not indicate which tasks were to be done, however.
Henry Gantt and Karol Adamiecki.
A novel method of displaying interdependencies of processes to increase visibility of production schedules was invented in 1896 by Karol Adamiecki, which was similar to the one defined by Gantt in 1903. However, Adamiecki did not publish his works in a language popular in the West; hence Gantt was able to popularize a similar method, which he developed around the years 1910–1915, and the solution became attributed to Gantt. With minor modifications, what originated as the Adamiecki's chart is now more commonly referred to as the Gantt Chart.
Publications.
Gantt published several articles and books. A selection:


Aerial bundled cable

Aerial bundled cables (also aerial bundled conductors or simply ABC) are overhead power lines using several insulated phase conductors bundled tightly together, usually with a bare neutral conductor. This contrasts with the traditional practice of using uninsulated conductors separated by air gaps. This variation of bundled conductors utilizes the same principles as overhead power lines, except that they are closer together to the point of touching but each conductor is surrounded by an insulating layer (except for the neutral line).
The main objections to the traditional design are that the multiple conductors are considered unappealing, and external forces (such as high winds) can cause them to touch and short circuit. The resultant sparks have been a cause of bushfires in drier climates. In the UK where some supplies to rural property are converted to PME/MEN from TT Earthing system concerns have been expressed that the lower conductor alone may be broken, (by high vehicle or falling tree for example) but with the upper phase conductors intact. This is a potentially dangerous fault condition. With ABC, a simultaneous disconnection of all conductors is more likely.
In moister climates, tree growth is a significant problem for overhead power lines. ABC will not arc over if touched by tree branches. Although persistent rubbing is still a problem, tree-trimming costs can be reduced.
Areas with large trees and branches falling on lines are a problem for ABC as the line degrades over time. Due to the very large strain forces cracking and breaking insulation can lead to short circuit failures which can then lead to ground fires due to dripping of molten insulation.
Low voltage ABC has already been developed in several countries across the globe and promises to be cheaper, safer, more reliable, require less tree clearing and pruning, be more aesthetic, be less labor intensive, require less maintenance and eliminate bushfires being initiated by conductor clashing.
International usage.
Australia.
ABC have been introduced into Australian power systems progressively since 1983. This was partly in response to bushfires sparked by old wires touching.
In some bushfire prone areas though, older ABC installations are now creating fires, particularly at points where the cables have damaged or been degraded over time.
In the Dandenong Ranges area Victoria 2014. Medium voltage (11-22 kV) ABC is being replaced with underground cable due to high failure rates of HV ABC, with life expectancy of just 10 years, when original life was expected to be approx 30 years. Due to degraded cable, cost of repairs & maintenance and bushfire risk.
Ireland.
Low voltage ABC lines were first installed on the rural Irish distribution networks in 1981. It is not known where ABC was first installed.
Pakistan.
K-Electric first introduced ABC, in Gulshan-e-Iqbal area of Karachi city with a pilot project was completed in march 2014. Following 90% theft loss reduction, the decision to roll out the new cabling across the entire K-Electric distribution network of Karachi.
Sri Lanka.
Low voltage ABC lines are installed in urban distribution systems commonly.
External links.


Bor rifle

The Bor is a Polish bolt-action 7.62×51mm NATO and .338 Lapua Magnum caliber sniper rifle. The weapon received the code name Alex during development, after the name of the lead designer Aleksander Leżucha, creator of the 12.7×99mm NATO Wilk anti-materiel rifle. After the development phase, the rifle received the military designation 'Bor'.
Development.
After 1999, when Poland became a member of the North Atlantic Treaty Organization, there was a need for new firearms for the Polish Armed Forces compatible with NATO standards. Starting in the early 2000s, at the Mechanical Equipment Research and Developing Centre ("Ośrodek Badawczo Rozwojowy Sprzętu Mechanicznego" – OBR SM) in Tarnów, engineer Aleksander Leżucha started his work on a new standard sniper rifle. The work on the Alex had financial backing of the Polish Science Research and Information Technology Ministry in a joint venture construction with the manufacturer OBR SM Tarnów. It is intended that this sniper rifle will ultimately replace all precision rifles of this caliber in Polish service (currently (2009) mostly SVD).
In the summer of 2005, testing of the new rifle began. The Bor was first unveiled at the 12th International Defense Industry Exhibition MSPO in September 2005 in Kielce. The weapon then went into production in 2006, when a short series was made.
In the spring of 2007 the 7.62 mm Bor had passed all the tests required to be introduced into Polish inventories. The Polish Armed Forces planned to acquire 36 Bor rifles in 2007. In 2008 the manufacturer received an order for the delivery of a batch of 81 Bor rifles chambered for the 7.62×51mm NATO cartridge by 2010.
In June 2011 the manufacturer received an order for the delivery of 55 modified Bor rifles chambered for the 7.62×51mm NATO cartridge by 2013. Several years of operations, including missions in Iraq and Afghanistan, has allowed to gain experience with the rifle. In accordance with the suggestions of users several improvements to the sniper weapon system were introduced including a 15 MOA forward canted Rail Integration System mounted over the receiver and a forward mounted tri-rail for mounting aiming optics and a new night vision device (Carl Zeiss Optronics NSV 80 Night Sight Attachment). Further the bipod, trigger, magazine well and bolt action were modified and the original barrel was exchanged for a new barrel with increased durability and corrosion resistance.
Design details.
The Bor is a bullpup-configuration bolt-action magazine-fed sniper rifle. The configuration provides increased accuracy by allowing a barrel length of , but minimizes the overall length of . Weight is further reduced without sacrificing accuracy by the use of a free-floating fluted barrel. The muzzle is fitted with a double-baffle muzzle brake, which is claimed to reduce recoil by up to 30%. The "in-line" design of the barrel-receiver group also directs recoil rearwards in a straight line, minimizing muzzle flip. A sturdy adjustable bipod is fitted to the front of the fore-end. The rifle features a fully adjustable buttstock and cheek riser. A folding/adjustable monopod located behind the magazine on the inside of the buttstock can be used to support the rifle in firing position during extended periods of deployment. No iron or emergency sights are provided; a MIL-STD-1913 Picatinny rail is mounted above the centerline of the barrel, over the receiver area for mounting various optical sights. The standard telescopic sight is a Leupold 4.5–14×50, with sight grid mil-dot reticle, parallax correction and an adjustment range of 100 MOA.
Variants.
Alex-338 prototype.
Around 2007, OBRSM Tarnów has begun development of a .338 Lapua Magnum chambered model under the Alex-338 development designation (the manufacturer's code for the basic Alex/Bor was changed then to Alex-762). Early in 2008 the Mechanical Equipment Research and Developing Centre in Tarnów completed the design work and in June 2008 the first prototype was assembled.
The model was publicly presented at the MSPO in Kielce, Poland in September 2008. The .338 Lapua Magnum version of the Bor is externally slightly different from the earlier 7.62 mm rifle . The lower assembly has a different shape. The Alex-338 weighs 6.5 kg without aiming optics and 7.3 kg with the standard Leupold telescopic sight mounted. It uses the same 5-round detachable box magazines as the Finnish Sako TRG-42 sniper rifle. Like the 7.62 mm Bor the Alex-338 shares some characteristics with the French PGM Précision PGM 338 rifles. The eventual introduction of weapons chambered for the specialized .338 Lapua Magnum rimless bottlenecked centerfire cartridge developed for military long-range sniper rifles will be a novelty in the Polish Armed Forces.
Alex Tactical Sport 308 Winchester.
The Alex Tactical Sport 308 Winchester is a variant based on the Polish Armed Forces 7.62×51mm NATO Bor rifle. It is chambered for the .308 Winchester cartridge – which is very similar to the 7.62×51mm NATO cartridge – and is intended for the civilian market. As such the Alex Tactical Sport is adapted to the needs of sportsmen and law enforcement and the design has been simplified – reducing the number of rifle components. The Alex Tactical Sport weighs 5.3 kg, has a 660 mm long barrel and feeds from a double stack 10-round box magazine. It was presented to the shooting public on 8–11 March 2013 at the IWA & OutdoorClassics fair in Nuremberg.


Synapse (software)

Synapse is a free and open-source application launcher for Linux originally created by Michal Hruby and Alberto Aldegheri.


Remington Model 34

The Remington Model 34 is a bolt-action rifle that was manufactured by Remington Arms from 1932 until 1935.
Design.
The Model 34 is a conventional bolt-action, tube fed rifle. Though conventional in layout and design, the Model 34 and 341 feature a patented lifter mechanism that presents cartridges to the chamber without the bullet touching rear of the chamber. This prevents damage to the bullet and conceivably increases accuracy potential. Remington updated the Model 34 and the Model 341 replaced it in the product line.


Baku Ferris Wheel

Baku Ferris Wheel, also known as the Baku Eye and Devil's Wheel (), is a ferris wheel on Baku Boulevard in the Seaside National Park of Baku, capital of Azerbaijan.The wheel was built by the Dutch company Dutch Wheels. It was opened 10 March 2014 by Azerbaijani president Ilham Aliyev, and opened to the public two days later.
The wheel is tall and has 30 enclosed cabins, each holding eight people, except for two VIP cabinets for four people. It makes a complete turn in 30 to 40 minutes. The cabins of the Ferris Wheel are equipped with air conditioners. Small monitors have been set up so that passengers can spend their time entertaining. The doors of the attraction are opened and closed in a centralized manner in order to ensure safety. At the same time, with this purpose all the cabinets are covered with transparent glass constructions. There are special ladders for each cabinet, which is designed to facilitate the evacuation of passengers in the case of any malfunction in the attraction. Users of "Satan's Ride" have the opportunity to gaze the Baku Bay, the Flag Square, the Crystal Hall and the whole city.


John Milton Hancock

John Milton Hancock (February 2, 1883 – September 25, 1956) was an American engineer, navy man, interim-manager and Wall Street banker. He is known for distinguished achievement in industrial management in the private and public sector, for which he has been awarded the Henry Laurence Gantt Medal in 1944.
Biography.
Youth and education.
Born in Emerado, North Dakota in 1883, Hancock was the son of Henry and Isabel (Irvine) Hancock. A 1950 newspaper article recalled, that "it was thirty below zero the February 2, 1883, that John Milton Hancock was born in Emerado... by the light of a kerosene lamp. If life in North Dakota lacked modern conveniences, it was also remarkably free of modern apprehensions."
Hancock's father originated from Canada, had set up a farm in North Dakota in 1878, and had founded the town of Emerado. In town he was also partner in the local hardware store and a realtor in the township. The family originated from Britain, and one of their forebears had been British drummer boy at the Battle of Waterloo.
In 1897 the family moved to Grand Forks, North Dakota, where after preparatory college Hancock attended the University of North Dakota obtaining his AB in 1903. At the University Hancock participated in the football team, until serious injuries forced him out of the game three years later. In those days he also participated in the newly founded literary society, and was editor-in-chief of "The Student," the student magazine of the university.
Early career in the US navy.
After a year as principal in a high school in Tower City, North Dakota, Hancock enlisted in the US Navy in 1904. He joined Bureau of Supplies and Accounts, and started as storekeeper in Olongapo Naval Station in the Philippines, now the U.S. Naval Base Subic Bay, and out on the see with the USS Galveston. In the last five years before World War I Hancock served Navy yards back in the States in Boston, Philadelphia, and Puget Sound, and returned to the Philippines to the Naval Base Cavite. he was on the "Wilmington"-class gunboat "USS Helena" on the Yangtze River in China, when war broke loose.
In 1914 Hancock was appointed head of the US Navy Bureau of Supplies and Accounts, and was promoted to the rank of lieutenant commander in 1916, and commander in 1918. The University of North Dakota (2017) recalled that "ss head of the purchasing division, Hancock made purchases of Navy supplies in excess of $2 million per day. He designed a system based on commodity sections: estimates were made to reflect as closely as possible the Navy’s material needs, and contact was maintained with the country’s industries. The Navy's newly legalized authority to award contracts based on profitability prompted the War Industries Board to form a price-fixing committee, of which Hancock was a member. From April to August 1917, he served on the General Munitions Board, and in 1919 accompanied Franklin D. Roosevelt, then Assistant Secretary of the Navy, to dispose of accumulated naval equipment overseas. Hancock also established organizations to settle claims against the Navy."
Private sector and back in Washington.
After World War I Hancock moved to the private sector to join the Lehman Brothers in New York City, where he came into prominence. His first assignment was the reorganization of the Jewel Tea Company in Chicago, Illinois, nowadays part of Jewel (supermarket). Again the University of North Dakota (2017), recalled that the "Jewel Tea Company, Chicago, Illinois... had been financed by them and was now deep in debt. The company had been operating at an annual loss of $2 million, along with a substantial debt of $4.5 million. Hancock came on board as vice-president and under his watch implemented corrective strategies: unprofitable branches were closed, low-volume routes were dropped, inventories were substantially reduced to provide badly needed cash, common dividends were canceled, and preferred dividends were deferred. After these changes were implemented, the result was a complete turnaround for the company. By 1924, the company's annual profit was $750,000."
In 1922 Hancock had been appointed assigned president of the Jewel Tea Company, and in 1924 he became partner in Lehman Brothers, a milestone since he was the first partner not to be a Lehman family member. In the next decennia Hancock was interim-director in more company's such as Sears, Cluett Peabody & Company, Brunswick Corporation, and Kroger. In the 1930s he also got into civil affairs.
Hancock was also involved in civil affairs again. He was executive officer in the National Recovery Administration in 1933, member of the War Production Board in 1939, and assistant director in the Office of War Mobilization in 1943 appointed by President Franklin D. Roosevelt. In 1942 he had done a government survey of the rubber industry with Bernard Baruch, and in 1946 again joined him as general manager of the U.S. Delegation to the United Nations Atomic Energy Commission.
Reception.
One of Hancock's most remarkable accomplishments was reported in "Time (magazine)" in 1944:
In recognition of his achievements Hancock received US Navy Distinguished Service Cross in 1919, the Henry Laurence Gantt Medal in 1945 by the American Management Association and the ASME, and the US Army Medal of Merit in 1948. In 1950 the Hamilton College in New York, and the New York University both granted him an honorary degrees.


South African Institute of Electrical Engineers

The South African Institute of Electrical Engineers (SAIEE) is a professional association representing electrical and electronic engineers, technologists and technicians in Southern Africa. The organisation is listed as a recognised Voluntary Association by the Engineering Council of South Africa (ECSA), the statutory body that registers professional engineers, professional certificated engineers, professional engineering technologists and professional engineering technicians in South Africa. Over a century, the activities of the SAIEE have included publication, education, the promotion of electrical engineering,professional development of its members, public events, and participation in public debate affecting the profession, industry and society.
Sections.
The SAIEE has sections that cover the following aspects of electrical engineering:
Education.
The SAIEE administers a number of university bursaries and scholarships in the field of electrical and electronic engineering in South Africa. Through its marketing and outreach activities, the organisation promotes engineering, and encourages young people to enter the profession. The SAIEE also provides accreditation for courses for Continuing Professional Development (CPD) points, as required by ECSA for renewal of professional registration.
Seminars and Lectures.
The SAIEE runs regular seminars, lectures and other events for its members and the public. Notable annual events include the Bernard Price Memorial Lecture, arranged jointly with the University of the Witwatersrand since 1951, and the President's Invitation Lecture.


HMS Glowworm (H92)

HMS "Glowworm" was a G-class destroyer built for the Royal Navy in the mid-1930s. During the Spanish Civil War the ship spent part of 1936 and 1937 in Spanish waters, enforcing the arms blockade imposed by Britain and France on both sides of the conflict. "Glowworm" was transferred from the Mediterranean Fleet shortly after the beginning of World War II to the British Isles, to escort shipping in local waters. In March 1940, she was transferred to the Home Fleet, just in time to participate in the opening stages of the Norwegian Campaign. On 8 April 1940 "Glowworm" encountered German destroyers transporting troops to invade Norway in Operation Weserübung. The destroyers attempted to disengage while calling for help from the heavy cruiser . "Glowworm" was heavily damaged by "Admiral Hipper", but still attempted to torpedo the German ship. In chaos of the battle, the heavily damaged "Glowworm" ended up ramming "Admiral Hipper", which broke the bow off "Glowworm", and she sank shortly afterwards.
Description.
"Glowworm" displaced at standard load and at deep load. The ship had an overall length of , a beam of and a draught of . She was powered by Parsons geared steam turbines, driving two shafts, which developed a total of and gave a maximum speed of . Steam for the turbines was provided by three Admiralty 3-drum water-tube boilers. "Glowworm" carried a maximum of of fuel oil that gave her a range of at . The ship's complement was 137 officers and men in peacetime.
The ship mounted four 45-calibre 4.7-inch (120 mm) Mark IX guns in single mounts. For anti-aircraft defence "Glowworm" had two quadruple Mark I mounts for the 0.5 inch Vickers Mark III machine gun. She was the test ship for the new quintuple torpedo tube mounts for torpedoes. One depth charge rail and two throwers were fitted; 20 depth charges were originally carried, but this increased to 35 shortly after the war began.
Operational history.
Early career.
"Glowworm" was ordered from the yards of John I. Thornycroft and Company, at Woolston, Hampshire on 5 March 1934 under the 1933 Construction Programme. She was laid down on 15 August 1934 and launched on 22 July 1935. She was completed on 22 January 1936 at a total cost of £248,785, excluding government-furnished equipment like the armament. Upon commissioning she was assigned to the 1st Destroyer Flotilla of the Mediterranean Fleet. "Glowworm" patrolled Spanish waters during the Spanish Civil War enforcing the edicts of the Non-Intervention Committee until she had a refit at Portsmouth between 27 May and 8 June 1937. The ship returned to the 1st Destroyer Flotilla in the Mediterranean after her brief refit. "Glowworm" returned to Portsmouth for a longer overhaul between 7 June and 25 July 1938 and escorted the ocean liner SS "Strathnaver" between Malta and Alexandria during the Munich Crisis in September 1938. She then escorted the light cruiser on her voyage to Aden later that month. During night exercises on 16 May 1939, "Glowworm" collided with her sister, , and was forced to put into Alexandria for temporary repairs. She received permanent repairs in Malta between 23 May and 24 June.
"Glowworm" was in Alexandria when World War II began in September 1939. In October the flotilla was transferred to the Western Approaches Command and "Glowworm" sailed for the UK on 19 October with her sisters , , and . They arrived at Plymouth on 22 October and were deployed in the South Western Approaches. "Glowworm" carried out convoy escort duties and anti-submarine patrols until 12 November when she was transferred to the 22nd Destroyer Flotilla, based at Harwich, for North Sea patrol and escort duties. On 22 February 1940 she was hit by the Swedish ship "Rex" in fog whilst at anchor off Outer Dowsing. "Glowworm" suffered significant structural damage and was under repair at a commercial dockyard in Hull until late March. On completion of the repairs, she was transferred back to the 1st Destroyer Flotilla of the Home Fleet, rejoining the flotilla at its base at Scapa Flow on 20 March.
On 5 April "Glowworm" was part of the escort of the battlecruiser , along with her sisters "Greyhound", , and . The ships covered the minelaying operation in Norwegian waters, Operation Wilfred. On 7 April, "Glowworm" was detached from the task force to search for a man lost overboard.
Final battle.
On the morning of 8 April 1940 "Glowworm" was on her way to rejoin "Renown" when she encountered the German destroyers and in the heavy fog before 8:00 a.m. The destroyers were part of a German naval detachment, led by the heavy cruiser , on its way to land troops at Trondheim as part of the German invasion of Norway ("Operation Weserübung"). "Glowworm" opened fire and the German destroyers attempted to disengage, signalling for help. The request was soon answered by "Admiral Hipper" which spotted "Glowworm" at 09:50. "Hipper" initially had difficulty in distinguishing "Glowworm" from "von Arnim", but opened fire eight minutes later at a range of with her main guns. "Glowworm" was hit by "Hipper"s fourth salvo and she started making smoke. She turned into her own smoke in an attempt to break visual contact with "Hipper", but the cruiser's radar-directed guns were not affected by the smoke. When the destroyer emerged from her smoke the range was now short enough that the cruiser's guns could fire. "Glowworm"s radio room, bridge, and forward 4.7-inch gun were all destroyed, and she received additional hits in the engine room, the captain's day cabin, and finally the mast. As this crashed down, it caused a short circuit of the wiring, causing the ship's siren to start a banshee wail.
At 10:10, Lieutenant Commander Gerard Broadmead Roope fired five torpedoes from one mounting at a range of , but all missed because Captain Hellmuth Heye had kept "Hipper"s bow pointed at "Glowworm" throughout the battle to minimize his risk from torpedoes. The destroyer fell back through her smoke screen to buy time to get her second torpedo mount working, but Heye followed "Glowworm" through the smoke to finish her off before she could fire the rest of her torpedoes. The two ships were very close when "Hipper" emerged from the smoke and Roope ordered a hard turn to starboard to ram the cruiser. "Hipper" was slow to answer her helm and "Glowworm" struck the cruiser just abaft the anchor. The collision broke off "Glowworm"s bow and the rest of the ship scraped along "Hipper"s side, gouging open several holes in the latter's hull and destroying her forward starboard torpedo mounting. One German sailor was knocked overboard by the collision. "Hipper" took on some of water before the leaks could be isolated, but was not seriously damaged. "Glowworm" was on fire when she drifted clear and her boilers exploded at 10:24, taking 109 of her crew with her.
"Admiral Hipper" hove to in order to rescue her man overboard and "Glowworm"s survivors. The German sailor was not found, but 40 British sailors were recovered, although at least six later died of their wounds. Lieutenant Ramsay, the senior surviving officer, told his rescuers that neither the helm nor the emergency rudder were manned when the ships collided so the destroyer's turn towards "Hipper" was probably accidental. German accounts only mention four torpedoes fired by "Glowworm", but British accounts say all ten were fired. This was confirmed by photographic evidence taken after the collision showing all of her torpedo tubes empty.
Roope, who drowned when he could no longer hang on to a rope whilst being pulled up the side of the cruiser, was posthumously awarded the Victoria Cross, thus becoming the first VC recipient of the Second World War. The award was justified, in part, by the recommendation of Heye, who wrote to the British authorities via the Red Cross, giving a statement of the valiant courage Roope had shown when engaging a much superior ship in close battle. Ramsay was also awarded the DSO. Both awards were made after the end of the war.


GNOME Panel

GNOME Panel is a highly configurable taskbar for GNOME. It formed a core part of the GNOME desktop in versions 1.x and 2.x. It has been replaced in GNOME 3.x by default with GNOME Shell, which only works with the Mutter window manager.
There are many "applets" for GNOME Panel available in one package called "gnome-applets" while some applets included with GNOME Panel as built-in, like a traditional start menu.
GNOME Panel served as Fallback Mode until GNOME 3.8 when Mutter could not be executed, then it was replaced with a suite of officially supported GNOME Shell extensions named GNOME Classic. Now it is part of GNOME Flashback, an official session for GNOME 3 which provides a user experience similar to GNOME 2.
In GNOME 3, customizing GNOME Panel is done by pressing the key while right-clicking on the panel.
Appearance.
By default, GNOME Flashback contains two panels (one on the top, and one to its opposite on the bottom) spanning the width of the screen.
The top panel usually contains navigation menus labeled "Applications" and "Places" in that order, as the "System" menu from GNOME 2.x has been replaced by a control panel in GNOME 3.x. These menus hold links to common applications and areas of the file system, respectively.
A user menu placed on the opposite side of the screen, which has been available since GNOME 2.14 but has become more prominent in GNOME 3.x, holds access to account and system settings as well as options to log out, switch user, and shut down the computer.
The top panel usually contains a clock/calendar and a notification area, which can double as a sort of dock, as well. The bottom panel is commonly empty by default (other than a set of buttons to navigate between desktops) due to its use in the navigation between windows (windows minimize to the bottom panel by default).
Customization.
Users can populate these panels with other completely customizable menus and buttons, including new menus, search boxes, and icons, with the icons in particular (called "launchers") performing functions similar to the "quick-launch" feature found in the Microsoft Windows 98–Vista taskbar. GNOME 2.x accomplishes this via right-clicking on an applet and selecting options from a menu; in GNOME 3.x, one must press the key while right-clicking to attain the same functionality.
Other applications can also be attached to the panels, and the panels are highly reconfigurable: anything on these panels can be moved, removed, or configured in other ways. For example, a migrating Microsoft Windows user might move the menus usually positioned in the top panel into a 'start' menu on the bottom panel as well as moving the notification area into the place normally positioned by the Windows notification area, then remove the top panel altogether, to interact with GNOME Panel similarly to the Windows taskbar.
The version of GNOME Panel available in the repository for Ubuntu 12.04 offers a modified version of Fallback Mode with the addition of a custom theme and ports of Ubuntu's own Indicators from their old GNOME 2.x desktop. Trisquel GNU/Linux uses Fallback Mode (Flashback) for its main desktop, because GNOME Shell requires 3D acceleration as it relies on graphics composition, while some free software drivers do not support 3D acceleration, among other reasons like more usability and more stability.


Peterson Electro-Musical Products

Peterson Electro-Musical Products, Inc. is a music-electronics company founded by Richard H. Peterson in 1948. The Peterson company introduced the first commercial handheld electronic tuner for musicians, the Model 70, in 1964, and later its models of strobe tuners became popular among touring and studio musicians such as the Grateful Dead, The Who, Pink Floyd, Queen, Frank Zappa, Jimi Hendrix, and Neil Young. Since its inception the company has also contributed notable inventions and innovations to the electronic organ, and its products are in use in many thousands of pipe organs, and hundreds of thousands of electronic organs, worldwide.
Company history.
Founder Richard H. "Dick" Peterson (born February 26, 1925, died January 29, 2009), was born in Chicago. In his teens, he began developing a keen interest in radios, vacuum tube circuits, and pipe organs. He served as a radio operator for the U.S. Army near the end of World War II, and while stationed in New York City, developed a further fascination with the sound and mechanics of pipe organs. He founded Haygren Organ Company to build electronic pipe organs with a sound he felt better matched real pipe organs, and was the first to use multiple oscillators in the organ design to produce a genuine ensemble. He also focused on the realistic attack and decay of individual electronic notes.
Peterson founded Peterson Electro-Musical Products in 1948. He soon licensed his inventions to the Gulbransen Piano Company of Chicago to use in home electronic organs. In 1957, Peterson completed the world's first transistor organ for Gulbransen. The company went on to produce other products for musical tuning, electronic organs, home security, and keyboards, and later developed and produced electronic and electro-mechanical equipment used in pipe organs.
In 1964, the Peterson company built a new headquarters in Alsip, Illinois, on a plot of . They built two additional buildings totaling on the company site between 1975 and 1977.
In 1985, the Conn Tuner company closed. Peterson bought their Strobotuner division, and continue to service the Strobotuner product line, which is now made in China.
In 1991 Dick Peterson's son Scott R. Peterson became Company President, after previously serving as Design Engineer, Production Manager, and Vice President.
In 1998, the Peterson Company celebrated its 50-year anniversary by creating the "Beer Bottle Organ" prototype in the exhibit area of the American Institute of Organ Builders convention. The "BBO" used pipe organ components and beer bottles with liquid, precisely tuned with a Peterson strobe tuner, to produce a clear, flute-like musical sound when played with a keyboard or via recorded MIDI files. Peterson Electro-Musical Products, Inc. is still family owned, and still has an active research and development program for tuner and pipe organ-equipment product lines.
Tuner product history.
The first Peterson tuner, the Model 150, was released in 1952, after Peterson developed it for their own use in tuning organs. The Model 150, and the Model 200 released in 1959 were the first products to carry the Peterson name. These tuners used vacuum tube technology and produced a wide range of finely adjustable audio tones. The design advanced to solid state with the Model 300 in 1966.
Peterson engineer, Bill Hass (born February 6, 1939, died May 3, 2008), built the first commercially available battery-powered handheld tuner, the Model 70, in 1964. The Model 70 was a chromatic tuner that generated twelve fixed pitch reference tones. The user tuning an instrument set the tuner to a pitch and matched the tone.
In 1967, Peterson introduced its first strobe tuner, the Model 400. It was the first solid-state strobe tuner on the market, and did not require calibration. Musicians could select one-cent increments. The tuner was highly influential in Peterson Tuner's growing presence in the fledgling tuner industry.
The rise of popular music as a business force in the 1960s and 1970s brought increased demand for professionalism in performance and recording. The only commercially available tuners in that era were manufactured by Peterson and Conn, which led to their presence on most major records and live concerts. The Peterson models became highly popular among leading touring and studio musicians, and were frequently used onstage by such bands as the Jimi Hendrix Experience, The Rolling Stones, Grateful Dead, The Who, Pink Floyd, Frank Zappa and the Mothers of Invention, Queen, Neil Young and Crazy Horse, the Bruce Springsteen Band, and many others. The tuner also became popular for precision tuning by school bands, top-level orchestras, and musical instrument manufacturers.
In 1980 Peterson introduced the Model 100 tuner—designed exclusively for guitars. The tuner used the strobe concept to create a rolling LED display that indicated pitch error by the speed of the rolling LEDs. The Model 100 sold successfully in the early 1980s and stayed on the market for nearly a decade.
In the 1990s, Peterson made the first significant change to the spinning wheel strobe since the late 1960s. They introduced the "Strobe Center 5000" (SC5000), which used twelve microprocessor-controlled digital stepper motors—one motor for each note in an octave. The strobe can change keys and temperaments, can store stretch tuning tables in a memory bank, and is a true polyphonic tuner. Widely used by school bands for its visibility and by instrument makers for its ability to show harmonic content, the Strobe Center 5000 remains Peterson's flagship strobe tuner.
After the Strobe Center 5000, Peterson Tuners re-designed their mechanical strobe tuning line and introduced a line of AutoStrobe series tuners. These selected the note automatically and offered programmability for advanced users. Besides the Strobe Center 5000, the AutoStrobe tuners are the only mechanical strobe tuners still made. Models include:
Virtual Strobe product line.
In 2001, Peterson Tuners developed a line of Virtual Strobe electronic strobe tuners that use a LCD dot-matrix display to emulate a mechanical strobe disc wheel, creating a stroboscopic effect. Peterson began using the "Strobo" name for all of its new Virtual Strobe line of products. According to the company, this was a response to other manufacturers using the word "strobe" for non-strobe tuners. The Peterson 'strobo' tuner line guarantees 1/10th cent accuracy, or higher by using patented technology. Peterson claims the Virtual Strobe display delivers higher resolution than needle or LED-based tuners.
Peterson Virtual Strobe tuners offer specialized tuning solutions for various instruments, referred to by Peterson Tuners as "sweeteners". According to Peterson, "sweetening" a tuning means using consonance and dissonance to affect the sound of a specific instrument, ultimately aiding creation of tension and release in music.
Peterson strobe tuners are loaded with presets that see a particular tuning as a group of notes (not just individual pitches) and, because of their high tuning resolution, can optimize the notes within these groups, making them more consonant with one another.
Peterson coined "sweetening" to distinguish between temperaments and 'other' exclusive sets of offsets. A temperament, by definition, implies the use of no more than 12 offsets, one for each pitch in the 12-tone chromatic scale. These offsets form a "template" octave. C0, C1, C2 through C8 for example, all have the same cent offset defined for 'C'.
Peterson "sweetened" presets are not temperaments because they do not necessarily pertain to a scale. They are sets of offsets for a particular instrument. The GTR sweetener, for example, accommodates the specific, common tuning problems inherent to a 6-string guitar. Unlike temperaments, the sweetener offsets only have musical benefit when applied to their intended instrument.
In 2001, Peterson introduced the model "VS-1" Virtual Strobe Tuner. The VS-II in 2003 had an improved display, additional features, and "sweetened" tunings. According to Peterson, it was also the first tuner to recognize and introduce dedicated tempered tuning presets for pedal steel guitar players. The V-SAM model, introduced later that year, added an audio output speaker and a metronome to the feature set of the popular VS-II. The VS-II was superseded by the StroboFlip in 2006.
In 2004, Peterson released the Virtual Strobe tuner model as a stomp box format. The StroboStomp2 replaced the first model in 2007. Both models of the StroboStomp featured true-bypass technology that would not 'color' the tone of the connected instrument and offered a studio-grade, on-board DI (direct injection box). The StroboStomp was discontinued in 2007. The StroboStomp2 was discontinued in 2009 and replaced by the VSS-C Stomp Classic. The StroboStomp, according to Peterson, was the first true-bypass tuner and the first strobe pedal tuner available commercially.
In 2006, the VS-II was replaced with the StroboFlip, a smaller version that could be used by musicians without a pedal board. It featured an innovative "Pitch Holder" that connected to the tuner with a tripod-like mount, allowing it to clamp onto music or mic stands. It is also the first tuner to specify the correct interval tunings for resophonic guitar and orchestral strings.
In 2007, the StroboRack was introduced and featured a large 7" tuning display that made it easily visible from a variety of angles and environments. The StroboRack is the world's first single-space rack-mount strobe tuner.
In late 2005, Peterson Tuners announced the release of the StroboSoft, a software based strobe tuner that can be used on Mac or PC to tune on your computer. StroboSoft provides the same tuning accuracy as the hardware products and can be used as a stand-alone tuner or as a VST/AU (StroboSoft 2.0) plug-in. The software package contains utilities for tuning and sound analysis, including a spectrum analyzer, oscilloscope, and linear pitch graph.
BB-1 & BBS-1 Tactile Metronomes
In 2008, Peterson released its first standalone metronome called the BB-1 BodyBeat, a small battery-operated device which, in addition to displaying and sounding the beat, also included a vibrating clip. This clip, called the "Vibe Clip" enabled the metronome to operate silently, transmitting the tempo via a tactile pulse felt by the user when the vibe clip was worn close to the body. The BB-1 was superseded in 2011 by the BBS-1 BodyBeat Sync which expanded upon the concept by adding a more powerful metronome engine, wireless synchronizing of multiple units and the ability to store midi tempo maps. In 2016 Peterson release the BodyBeat Pulse Solo, a vibing/tactile metronome that plugs into any audio metronome that has a 3.5mm headphone out jack including metronome apps. The BodyBeat Pulse converts the audio to a pulse and has a built-in rechargeable battery to power it.
VSS-C Stomp Classic
In 2010, the Stomp Classic replaced the prior StroboStomp2 product and added an improved DI, a larger display and multi-octave programmability. The stomp box design was also redesigned and modeled after the 1970s Conn ST-11 Strobotuner. It can connect to a computer via USB, and accepts altered tunings and sweeteners created on a special software editor made especially for the tuner.
The StroboClip, introduced in 2010, is a clip-on strobe tuner. It contains preset sweetened tunings for a variety of acoustic instruments, but can be used for electric guitar and bass players during on-stage performance. According to Peterson, the StroboClip was the first hardware tuner to feature the correct interval tuning for not just guitars and basses, but also for such diverse instruments as bagpipes, oud, banjo, sitar and Arabic maqamat (Eastern temperaments).
Mobile Tuning Apps for Apple Devices.
Peterson Tuners released a Virtual Strobe tuning application in 2009 as a professional-grade tuning app for Apple's iPhone and iPod Touch. The application leverages the Virtual Strobe display and provides chromatic tuning with Peterson's renowned standard tuning resolution of 0.1 cent. In 2010, Peterson released a native iPad version that offers unique functions on the iPad platform that includes VGA output support for classroom usage and manual note selection. An adaptor cable designed specifically for use with the Apple devices was also introduced to support the app and offer users an entry-level package solution. Per the iTunes store 7/14/2015, Peterson has renamed/created a new product for idevices called iStroboSoft.
In 2014 an in-app purchase of Petersons exclusive Sweetener library was added. The option of purchasing individual Sweeteners or instrument-based packs is offered. The addition of other tuning scope tools available as in-app purchases was also added including harmonic tuning, oscilloscope, spectrum waveform analyzer, and a full-color spectrogram.
In 2013 a version of iStroboSoft was released for the Android market. With a similar display to the ios version and the same 1/10th cent accuracy. The Android version does not have the in-app Sweetener or tuning scope options.
SP-1 StroboPLUS HD Tuner
2012 was marked by the release of the StroboPLUS HD which sported a menu of 90 Sweetened Tuning presets and temperaments for individual instruments, some of which had never been preset in a tuner before. The device is audio-visual and also has the capability of being expanded to have metronome functions via an upgrade. The addition of a computer-aided USB user interface called Peterson Connect allows users to configure their tuner to their own requirements including such controls such as strobe speed, pattern and backlight behaviors in addition to programming temperaments and Sweeteners. Notably, The StroboPLUS can be programmed with up to 128 target pitches in one preset, these pitches can be placed within one octave or spread over several octaves - as the user wishes, thus making it suitable for regular as well as microtonal tuning.
StroboStomp HD Tuner
2019 marked the release of the StroboStomp HD. This pedal tuner has a smaller footprint than its predecessor the Stomp Classic but a much larger tuning display. The full-color LCD display allows assigning colors to the different settings you have for each instrument for easy recognition and to maximize viewing in your environment. The StroboStomp HD offers pop-less true bypass, monitor mode or a buffered output.
Sponsors.
The following is a short list of notable musicians who frequently use Peterson Tuners in their gear setup:


Home (schooner)

The Home was a schooner that sank in Lake Michigan off the coast of Centerville, Manitowoc County, Wisconsin, United States. In 2010 the shipwreck site was added to the National Register of Historic Places.
History.
The "Home" was built in 1843. She spent most of her life on Lake Erie before operating on Lake Michigan. In 1858 the "Home" sank after an early-morning collision with another schooner called the "William Fiske" while en route from Manitowoc, Wisconsin to Chicago, Illinois. She lies in of water about southeast of Manitowoc.


William Loren Batt

William Loren Batt (July 31, 1885 – 1965) was an American mechanical engineer, and president SKF Industries, Inc., awarded the Order of Vasa in 1923, the Henry Laurence Gantt Medal in 1940, and the Hoover Medal in 1951.
Biography.
Batt was born in Salem, Indiana in 1885 to George M. and Hettie M. Batt. His father was a roundhouse foreman by the Chicago, Indianapolis & Louisville Railroad, who kept moving for his job to New Albany, Indiana and finally to LaFayette. Batt received regular education in those places, a got acquainted with the machinist's trade in the railway's shops during vacations. He obtained his B.S. degree in mechanical engineering at the engineering school of Purdue University in 1907.
After engineering school Batt started as assistant in the private consulting practice of W.F. M. Goss, Dean of Engineering department. When Goss moved to the University of Illinois, Batt started as engineer in the Hess-Bright Manufacturing Company to do research into ball bearings in 1907. After three years of laboratory work, he coordinated the application of his findings in various fields. He was put in charge of the Railway Department a few years, was sales engineer in the Cleveland area, and in 1917 got promoted to general manager of the company.
In 1918 the company got bought by the Swedish SKF and merged into SKF Industries, Inc., where Batt was appointed vice-president, and in 1922 president of the company. In 1923 he was awarded the Order of Vasa by Gustaf V of Sweden. In the tear 1936 Batt was president of the American Society of Mechanical Engineers (ASME), and in 1940 he was awarded the Henry Laurence Gantt Medal by the American Management Association and the ASME.
During World War II Batt made a significant contribution to the management and planning of war production. He was made vice president of the War Production Board in joined the Combined Munitions Assignments Board in 1943 as member. For these efforts he was awarded the Hoover Medal in 1951.