A security system for a personal computer, in which hardware and software are combined to provide a tamper-proof manner of protecting user-access and file-access. The hardware component of the system is an expansion board for insertion into an expansion slot of the PC, and has a first EPROM chip containing four portions of machine code for initializing system function calls and for establishing the proper boot-processing of the PC; a second RAM chip serving as scratch pad memory; a third EEPROM chip storing passwords, audit trail log, protection and encryption system flags, and user-access rights; a fourth automatic encryption and decryption chip for files of the PC; and a fifth clock chip for the audit trail. The software component includes a batch file that runs a program in conjunction with the machine code on the EPROM of the expansion board ensuring access is gained only for valid users. The code on the EPROM monitors all DOS 21H file handling function calls, and initializes the 7CH interrupt vector for allowing the security system to access DOS and the files thereof. During boot processing, the 10H video interrupt handler is monitored to prevent circumventing the security system. Hard-disc format-protection is also provided by monitoring of the 13H interrupt function calls. Files may also be created that may not be copied.

The present invention is directed to a security system for personal computers, often called microcomputers, and has specific application to the IBM line of personal microcomputers.
Microcomputers have grown in use and in number over the last decade, and are currently used by individuals, small business, medium-sized businesses, and large businesses. The use of these microcomputers runs the gamut from word processing to bookkeeping to engineering and scientific applications. Due to the ever-growing sophistication and possible applications of microcomputers, the number of them that can be expected to be in use ten years hence may quadruple that currently in use.
The microcomputer industry has not only grown by leaps and bounds, but has experienced intense competition among its many manufacturers. Standardization among the many different kinds of microcomputers is still in its early stages, but it is expected that such will ever-advance.
In the light of this intense competition, overall market growth, and the potential for such growth in the years to come, special security measures have only recently become a necessity in order to protect files from unwanted user access, and to protect access in general for only those users given such rights. Further, a security system that is practicable, useful, and safe also must be readily adaptable to all special uses and applications of microcomputers.
There are currently available microcomputer security systems that protect, in one way or another, the P.C. from unauthorized use, but these generally suffer from many disadvantages, such as lack of adequate range of security provided, lack of enough flexibility, are software-only systems that a capable programmer may easily circumvent, and lack of central control. Most prior-art security systems are simple password-type systems that simply allow or prevent access to the file or files based on the password entered, which is compared with a list of valid passwords stored in memory.


The invention relates to a device with a fuel cell or a stack of fuel cells, wherein one electrode of a fuel cell is separated from an adjoining channel or chamber through which an operating substance is supplied by means of a perforated plate. The size and/or the density of the holes increases towards the edge starting from a median line and the median line extends in parallel to the direction of flow of the operating substance. The inventive device more reliably avoids thermal gradients in the interior of the fuel cell or of a stack of fuel cells. In order to prevent the occurrence of temperature gradients, the device is cooled by evaporating a coolant in an external cooling system. The heat is mainly transferred by thermal radiation.

The invention relates to a fuel cell stack, in which several fuel cells are mechanically and electrically connected together.
Fuel cells are known from DE 44 30 958 C1 as well as from DE 195 31 852 C1, which have a cathode, an electrolyte and an anode. A passage or space adjacent the cathode is supplied with oxidation medium (for example air) and a passage or space adjacent the anode is supplied with fuel (for example hydrogen).
It is understood from DE 197 90 15 256 A1 that a distribution structure is provided in the above-mentioned passages or spaces. The distribution structures are of comb-like shape. This is to cause an even distribution of the working medium in each space.
The working medium reaches as far as the electrodes and is depleted there. Subsequently the depleted working medium flows out again, and is directed out of the fuel cell.
At the cathode of the known high temperature fuel cell of DE 4430 958 A1, anions are formed in the presence of the oxidation means. The anions pass through the solid electrolyte and recombine on the anode side with hydrogen coming from the fuel, to make water. The recombination will liberate electrons and so produce electrical energy. The working temperature of a high temperature fuel cell is typically about 800xc2x0 C.
At the anode of the known fuel cell of DE 195 31 852 C1 protons are formed in the presence of the fuel by means of a catalyst. The protons pass through the membrane (electrolyte) and combine on the cathode side with oxygen coming from the oxidation medium, to make water. Electrons will be liberated at the anode and consumed at the cathode, so that electrical energy is produced.
In order to achieve good efficiency, the working medium must be distributed evenly in three dimensions in the fuel cell.
The flow of the working medium in the fuel cell must be such as to avoid or nearly to prevent pressure loss. Loss of pressure leads to loss of performance.
In an electrode space of a fuel cell (the space in which the electrode is located) there is, as a rule, a mixture of gases and/or liquids. The combustion gases can be diluted by inert gases. Through reforming and oxidation, a fuel such as a methanol-water mixture can also have a further inert gas such as carbon dioxide present in the relevant electrode space. The cathode will be supplied regularly with air and thereby also with the inert gas nitrogen.
The gases or liquids found at each electrode may be homogeneously mixed together, in order to help performance.
If unhumidified gases, that is, humidified gases not separated in a humidification device, are introduced into a polymer electrolyte membrane fuel cell, the electrode surfaces will be particularly evenly supplied with the working medium. Otherwise, the threat of a local drying up of an electrode and even an electrolyte membrane is increased. Local drying up results in performance loss and can be the cause of damage. The existence of a temperature gradient can cause local overheating of the fuel cell. Local drying-up can then result.
The exhaust flow of the working medium parallel to the electrodes over a lengthy region increases its exhaustion. Accordingly, the exhaust flow reactions are quantitively distinguished, dependent on their location. The result is the appearance of a temperature gradient in a fuel cell.
Thermal gradients are in general to be avoided, as they can result in damage and reduced efficiency, so that the working temperature cannot be maintained at its optimum.
Accordingly, German patent application No. 198 08 331.9-45 has proposed, to solve the above-mentioned problem, the provision of a plurality of supply passages and adjacent exhaust flow passages. These passages have holes, adjacent to the electrodes of the fuel cell. The working medium flows through the holes at right angles to the electrode as well as the interface between the electrolyte and the electrode. In the same way, the outflow is also at right angles to these.
The holes are furthermore of different sizes, to obtain an even distribution of the gases along the electrode surfaces.
The above-described construction is disadvantageous because the plurality of passages is relatively expensive. The desired intermixing is also rather low.
In particular, the low intermixing is a disadvantage because of the appearance of local temperature gradients resulting from the reactions. A temperature differential causes low efficiency, because the working temperature locally differs from the optimum temperature.
The construction also the disadvantage that the separate supply and exhaust passages basically result in a halving of the areas, over which the working medium in the fuel cell or a stack of fuel cells flows. This disadvantage can in fact be balanced by a higher throughput. However, a higher throughput results in a greater pressure loss, and thereby lower efficiency.
The same applies to the areas, over which the depleted working medium flows out of the fuel cell or the fuel cell stack.
In fact, in a fuel cell the path between the separate supply and exhaust passages can be made very small in order to achieve enlarged entry and exit areas. However, this results in a worsening of the electrical contact between the fuel cells of a fuel cell stack and thereby reduced efficiency. A fuel cell stack is made up of several fuel cells, which are mechanically and electrically connected together by connecting elements.
According to a further German patent application, DE 198 53 911.8-45, it has been proposed to separate the electrodes of a fuel cell by a perforated plate in a passage or space adjacent the flat surfaces of the electrode. By a perforated plate is meant a flat member provided with holes. This plate is arranged parallel to the layers of the fuel cell (electrode and electrolyte layers). The corresponding working medium is supplied and exhausted through the adjacent space or passage. The holes in the plate are of macroscopic size, so that they are visible to the naked eye.
In the flow direction of the gases the density and/or the diameter of the holes in particular increase. This results in equal distribution, which leads to electrochemical reactions in the fuel cell being uniformly distributed. The existence of a temperature gradient can therefore be counteracted. In this arrangement the exhaust gas flow is the same as the supply gas flow.
The gases pass through the holes to the adjacent electrode. The gases flow out again uniformly indirectly through a neighbouring hole. In comparison with a fuel cell with separate supply and exhaust passages this achieves stronger intermixing (by swirling). Temperature gradients can therefore be avoided.
In particular in fuel cells which are subject to internal reforming or oxidation reactions, temperature gradients are present. The very rapid reforming reaction is limited in the usual fuel cells to a region of a few millimetres. The reaction is strongly endothermic. Thereby in a particular case of internal reforming, there is large intermixing which has the advantage of increasing the efficiency.
In the above-described implementation, a plurality of divided passages is avoided. The constructional expense is therefore small. It is only necessary to provide, for example, a perforated metal sheet between a connecting element of the fuel cell and the adjacent electrode.
In order to avoid temperature gradients in a fuel cell stack, it has further been proposed to cool a fuel cell by evaporation of a liquid cooling medium. The cooling medium either evaporates in the fuel cell stack, or it is supplied to a cooling device, which is arranged externally and at a distance from the fuel cell stack.
In the above-mentioned state of the art, it is an aim of the invention to provide a fuel cell or a fuel cell stack, in which the temperature distribution in the fuel cell is further improved. The aim of the invention is also the provision of a method for the particularly efficient working of the fuel cell or the fuel cell stack according to the claims.
The aim of the invention is achieved by a device with the features of claim 1. A method of operating the device is shown in the features of the secondary claim. The subsidiary claims describe advantageous developments.
According to the claims, the aim is achieved by a fuel cell stack, which is provided with an external and adjacent cooling device, through which a cooling medium flows. The cooling device is arranged close to the fuel cell stack and constructed so that the heat from the fuel cell stack is mainly transferred through thermal radiation from the fuel cell stack to the cooling line and the cooling medium, thus causing cooling of the fuel cell. The cooling is controlled so that the cooling medium is evaporated by the heat which is removed.
In comparison with the state of the art with the external or internal cooling by evaporation, the claimed construction is simple and inexpensive. In the above-mentioned mode of operation (cooling by evaporation) uniform cooling takes place, so that the temperature of the cooling medium remains constant.
It will be understood that an externally-arranged cooling device means one that is not integrated with the fuel cell stack. An external form of cooling can be compared cooling through endothermic chemical reactions (for example methane reforming reaction in an external plate heat exchanger according to DE 19716438 A1), but cooling by evaporation is preferred. It will be understood by the term evaporation cooling, that a medium is evaporated by heat absorption.
Preferably water is used as the evaporating medium.
On the basis of the external cooling operation by heating up media (gases, liquids), which do not go through a phase change, it appears that the temperature gradients in the fuel cell or in the fuel cell stack increase. An increase in the cooling temperature of the cooling medium accordingly varies the cooling operation. A corresponding temperature gradient appears in the fuel cell or the fuel cell stack.
This undesired effect can be prevented, by cooling through evaporation. The temperature of the cooling medium hardly changes at all. The corresponding cooling performance remains constant. Temperature gradients in the fuel cell or the fuel cell stack are therefore reduced.
The above-mentioned device operates in particular, so that at least 80%, and preferably at least 90%, of the heat given off by thermal radiation from the fuel cell is used for evaporation of the cooling medium. This form of heat transfer is simple and inexpensive in comparison with the heat transfer in the state of the art, in which a cooling medium is transported from the fuel cell to an external evaporator.
The operation of the fuel cell is arranged in particular so that heating of the cooling medium to boiling point or overheating of the evaporating liquid (evaporating cooling medium) does not take place.
In an advantageous development of the invention the fuel cell stack and the cooling device are arranged in a container. In this way a closed system is provided, which is protected from external disturbing influences. The operation of the device is therefore secured to a certain extent.
In a further advantageous development of the invention tubes acting as an evaporator are arranged in a casing or housing with the fuel cell stack. The cooling medium flows through the tubes. The tubes are arranged so that the fuel flows round them, as it enters and/or leaves the fuel cell or the fuel cell stack.
The cooling devices may be arranged horizontally and/or vertically in one or more of the gas supply spaces. By gas supply space will be understood a space arranged adjacent to the fuel cell or fuel cell stack, which supplies the working medium. Near the cooling device it acts preferably as a tube. Evaporating water is preferably used as the cooling medium, whose thermodynamic state is characterised by its wet steam region. Preheating to boiling point or overheating of the cooling medium, for example, water, can therefore not result, and thereby energy must be used in an avoidable way.
Advantageously, the cooling device, which is in particular developed as the evaporator is placed on the longer side of a fuel cell stack with a rectangular plan, as here the greatest flat surface is available. The heat transfer is then particularly large. The working medium comes in and goes out of the fuel cell stack on these longer sides, so that it will flow round these cooling devices, at least partially. The cooling devices, for example the tubes, are preferably made of metal.
The problem can furthermore be solved, in that a fuel cell electrode is separated from the flat surface of the electrode adjacent the passage or space by a perforated plate. A perforated plate is a flat element provided with holes. It is arranged parallel to the layers of the fuel cell (electrodes and electrolyte layers). The corresponding working medium will flow into and out of the adjacent space or passage. The holes or openings in the plate are of macroscopic size, visible to the naked eye.
The holes in the plate which are arranged at the edge of the plate relative to a mid-line of the plate are more densely arranged and/or larger than the holes which are closer to or at the mid-line. The perforated plate thus borders an anode space, so that the flow direction of the fuel runs parallel to the mid-line.
More working medium reaches the adjacent anode space through the larger openings in the perforated plate than through the smaller openings. The working medium will be converted electrochemically in the anode space. Heat is thereby generated. The more working medium that is converted, the greater is the resulting quantity of heat. Thus, by the provision of the claimed perforated plate less heat will be produced in the interior of an anode space than at the edge, because the larger holes allow a greater quantity of working medium to flow into the anode space. This edge of the anode space is situated in the region of the outer surface of a fuel cell or a fuel cell stack. The outer surface of a fuel cell or a fuel cell stack, through cooler surroundings, will be more strongly cooled than the interior of the fuel cell or the fuel cell stack. A temperature gradient in a fuel cell or in a fuel cell stack will thereby be avoided, bringing about a greater exothermic electrochemical consumption of the fuel adjacent the outer surface in comparison with an exothermic electrochemical consumption into the interior of the fuel cell or the fuel cell stack.
Gases also pass through the holes to the adjacent electrode. The gases flow out evenly and indirectly through an adjacent hole. The outflow, in comparison with a fuel cell with separate inlet and exhaust passages, is more greatly intermixed (by swirling). Temperature gradients are thus further avoided.
The constructional expense is small. It is only necessary for example to provide a perforated metal sheet between a connecting element of a fuel cell and the adjacent electrode.
The openings or holes in the perforated plate can be formed as desired. It is only necessary to ensure that the area of the passages in the above-mentioned edge region is greater than the area of the passages close to or at the above-mentioned mid-line. By area of the passages is to be understood the area through which the working medium flows through the perforated plate. It represents thus a sum of the areas of the holes in the claimed plate.
In an advantageous development of the invention the holes in the perforated plate are arranged symmetrically about the mid-line. Such a symmetrical distribution is partly responsible for the avoidance of temperature gradients.
The area of the passages at the edge region may be at least 5%, advantageously at least 20%, greater than the area of the passages close to the mid-line.
In a further advantageous development of the invention, the area of the passages through which a working medium flows through the perforated plate is increased in the flow direction to at least 10%, and preferably at least 100%. Such an increase in the flow direction is described in German Patent Application No. 198 53 911.8-45. This provision of the increased area of the passages will achieve, in addition to the above-mentioned operation, inflow of a working medium, not already in the inlet region completely into the corresponding electrode space. Thus, the continuing chemical reaction is not concentrated at the inlet region. In this way the avoidance of temperature gradients is further achieved.
The perforated plate is preferably made of a high-alloy, high-temperature steel (for example: X8 CrNiMoNb 16 16) or an electrically conducting ceramic (for example: La(Sr, Ca)CrO3). Such materials are suitable in particular for use in a high temperature fuel cell as they are high temperature and corrosion resistant.
In a further advantageous development of the invention the claimed plate is formed as a perforated metal sheet, which is welded to the connecting element (known as a bipolar plate or interconnector) in a fuel cell stack.
The anode spaces of the individual fuel cells are provided with the perforated plate in the above-mentioned manner in the interior of a fuel cell stack.
The perforated plates are made in particular of metal.
The operation of the perforated plate in a fuel cell stack is achieved independently of the evaporation cooling.
The operating temperature can be maintained approximately constant by optimisation of the follow parameters:
1. The distance between the evaporator tubes and the fuel cell stack
2. The number of evaporator tubes
3. The length to width relationship of the plan of a fuel cell stack
4. The dimensions of the area of the passages in the perforated plate.
The skilled person will be able to ascertain the optimal parameters by a few trials.


A de-icing and anti-icing composition in the form of an aqueous solution which includes sugars, and an inorganic freezing point depressant in the form of a chloride salt.

The current state of the art for coping with snow and ice on roads usually involves applying a deicer material such as a salt to the road surface. Sometimes antiskid materials such as sand or other aggregates such as gravel are added with or without a salt.
The use of salt and compositions having high concentrations of salt, cause an undesirable corrosive effect on vehicles, the road surface, and the environment with respect to the run off of water containing salt which contaminates the surrounding land and water.
Considering the above problems associated with salt formulations, there has been a continuing need for a deicing composition or formulation which can effectively melt snow and ice yet which reduces the corrosion and environmental contamination referred to above. In response to the above problems associated with the use of road salt, the prior art has looked to alternative formulations which are less corrosive and more environmentally friendly.
U.S. Pat. No. 5,635,101 (Janke et al.) relates to a deicing composition containing a by-product of a wet milling process of shelled corn. Corn kernels are steeped or soaked in a hot solution containing small amounts of sulfurous acid. The corn kernels are separated from the steep water and steep water solubles are used in the production of a deicing composition.
U.S. Pat. No. 4,676,918 (Toth et al.) relates to a deicing composition which comprises a mixture containing at least one component selected from a number of chlorides or urea and an admixture of waste concentrate of alcohol distilling that has a dry substance content of from 200 to 750 g/kg and from 10% to 80% by weight of water.
U.S. Pat. No. 6,080,330 (Bloomer) teaches a composition for use in preventing the formation of ice or snow on outdoor surfaces, such as roadways or aggregate stockpiles, and also for deicing surfaces upon which snow or ice has formed. The composition is formed from a waste product of the process of removing sugar from sugar beet molasses, also known as desugared sugar beet molasses.
The Janke et al., Toth et al. and Bloomer materials are naturally occurring substances with hundreds (if not thousands) of components such as complex carbo-hydrates, starches, sugars, proteins etc. and are normally used with a salt.
The above de-icing solutions now being introduced in the field employ agricultural residues e.g., corn based distillers solubles and solubles from the corn wet milling industries. These naturally occurring substances, which also include brewers condensed solubles, are extremely variable in composition, viscosity, film forming tendency, freezing temperature, pH etc., and consequently give varying performance when used in de-icing solutions. Depending upon the source and batch, these materials at low temperatures sometimes exhibit such resistance to flow that they cannot be applied evenly to a road surface or mixed with a chloride, rendering them virtually unsuitable for use.
Furthermore, these patents utilize materials which have highly undesirable or unnecessary ingredients leading to practical difficulties by manufacturers and users, such as stratification in storage, biological degradation, odor, plugging of filters and spray nozzles and environmental difficulties e.g. high biological oxygen demand due to the very high organic contents (about 40% by weight), presence of phosphorus compounds and heavy metals.
To improve quality and performance, and to meet current mandated standards, there is an immediate need for synthetic, chemically modified thickeners, and carefully purified materials which can be substituted for the currently used agricultural residues. Such a formulation would improve performance and reduce metal corrosion, spalling of concrete, toxicity and addresses environmental concerns.
It is therefore an object of the present invention to provide a deicing formulation which exhibits improved performance standards which overcomes the prior art problems described above.
It is a further object of the present invention to provide a deicing formulation which utilizes a synergistic combination of a low molecular weight carbohydrate and an inorganic freezing point depressant.
It is another object of the present invention to provide a deicing formulation which utilizes a low molecular weight carbohydrate to provide for improved ice melting properties and exhibits less corrosion.
It is a further object of the present invention to provide a deicing formulation which provides consistent physical and chemical properties, thereby assuring consistent quality and performance.
It is another object of the present invention to provide an economical, highly effective deicing formulation.
The present invention is based upon the discovery that low molecular weight (about 180 to 1,000) carbohydrates when used with an inorganic freezing point depressant such as a chloride salt has a synergistic effect upon freezing point depression. The formulation of deicing/anti-icing compositions employs carbohydrates of less than about 1,000 molecular weight, such as glucose/fructose, disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, hexasaccharides, and mixtures thereof. The broader operative range for the carbohydrate molecular weight is from about 180 to 1,500, with the range of about 180 to 1,000 being preferred.
The basic composition of the present invention consists of at least the first two of the following three components in aqueous solution depending upon ambient weather conditions, terrain, nature and amount of freezing/snow precipitation, and environmental concerns:
(1) Inorganic freezing point depressants preferably in the form of chloride salts which include magnesium chloride, calcium chloride and sodium chloride. Metal acetates e.g. calcium magnesium acetate, and other suitable acetates may also be used.(2) Low molecular weight carbohydrates in the 180 to 1,500 range (180-1,000 preferred). These carbohydrates can be obtained from a wide range of agricultural based products such as those derived from corn, wheat, barley, oats, sugar cane, sugar beets etc.
(3) Thickeners are used in certain applications as the third key component to increase the viscosity of the composition so that the liquid remains in contact with the road surface or with the solid particles in piles of rocksalt/sand, or rocksalt/aggregates, or salt alone, or sand or aggregate. Thickeners are mainly cellulose derivatives or high molecular weight carbohydrates. Typical molecular weights for cellulose derivatives are for methyl and hydroxy propyl methyl celluloses from about 60,000 to 120,000 and for hydroxy ethyl celluloses from about 750,000 to 1,000,000. Carbohydrate molecular weights range from about 10,000 to 50,000. Typically the composition of the present invention has a viscosity of about 0.1 to 3 poises at 25xc2x0 C.
These components are used in an aqueous solution in the following concentrations:
In a further embodiment of the present invention it has been found that certain low molecular weight sugars function as highly effective carbohydrates in the above formulations.
The above described compositions provide a de-icing and anti-icing formulation which can be formulated more uniformly to provide for more consistent properties from batch to batch, while at the same time providing for increased ice melting properties.
In the development of the present invention it was determined that the predominant organic constituents in the prior art dormulations described above were carbohydrates, and in one series of tests, Brewers Condensed Solubles (BCS),which was selected as a test sample, was diluted with water and separated into several fractions by the addition of increasing amounts of an ethanol/methanol 85/15 v/v mix. The characteristic of the various fractions and their freezing points when mixed with 15% magnesium chloride are tabulated below.
Fraction A consisted of essentially insoluble, high molecular weight polysaccharides, whereas Fractions B to D inclusive gave gummy residues of polysaccharides. Fractions A to D had little effect upon freezing point depression. Fraction E, the largest component, had a considerable effect upon freezing point and is a mixture of lower molecular weight polysaccharides.
Fraction E was also examined for ice melting characteristics at 25xc2x0 F. (xe2x88x924xc2x0 C.) in admixture with magnesium chloride employing SHRP H-205.2 Test Method for Ice Melting of Liquid Deicing Chemicals.
The last two figures were calculated from data in SHRP H-205.2. These results indicate the appreciable improvement over the commonly used sodium and calcium chlorides in ice melting characteristics when Fraction E and Brewers BCS are mixed with magnesium chloride. There is also a 14% improvement over the control when Fraction E is used. This, together with freezing point depression improvement indicates that an appreciably improved deicing solution can be formulated.
The next stage of the investigation consisted of attempting to isolate and define the active components in the Brewers BCS. This was done by first filtering employing a 0.45 micron membrane followed by ultrafiltration using a Model UFP-1-E-s (A/G Technology Corporation, Needham, Mass.) with a nominal cutoff at a molecular weight of 1000 and finally gel permeation chromatography (GPC) using a Waters LC Module 1 unit with a set of three ultrahydrogel columns and 50 mm Na2 HPO4 solution at pH7 as the mobile phase. The brewers BCS liquor had two major carbohydrate fractions (a) a low molecular weight fraction with the majority of components having a molecular weight of less than 1000, and (b) a high molecular weight fraction containing compounds with a molecular weight of 12,600 but with some components in the 1000 to 10,000 molecular weight range. Fraction E was found to have a chromatographic profile very similar to the low molecular weight fraction (a) above with a molecular weight of less than 1000. Cane Sugar DCS liquor had more components than the Brewers BCS but had similar high and low molecular weight fractions with similar molecular weight distributions.
In order to confirm that the low molecular weight fraction has the greatest effect upon freezing point depression, a further series of freezing points were measured using in this instance, Dead Sea Salt Solution from Jordan in lieu of laboratory grade magnesium chloride. Again the concentration of magnesium chloride was 15% by weight for all samples.
It was thus shown that low molecular weight (less than 1000) carbohydrates had the greatest effect upon freezing point depression. Based upon these experiments, it was concluded that the formulation of deicing/anti-icing compositions should employ compounds in the less than 1000 molecular weight range such as those tabulated below in Table 4:
There is available commercially a wide range of carbohydrates with varying carbohydrate compositions. An evaluation was conducted using simple sugars, disaccharides and polysaccharides in an attempt to determine the effect of molecular weight and solute concentration upon freezing point. The concentration of magnesium chloride used in the test was 15% by weight. The test results for simple carbohydrates and complex carbohydrates are tabulated below in Tables 5 and 6 respectively.
It can be seen from the results above that glucose is better than fructose and of the two dissaccharides lactose is somewhat better than maltose. The corn syrup DE20 has about 47% of mono to hexasaccharides and the DE44 grade has about 69%, and the latter grade is slightly better in reducing freezing point. Also Table 6 shows that there is a relationship between carbohydrate concentration and freezing point thus allowing various formulations to be developed.
More complex carbohydrates were also evaluated such as dextrins and maltodextrins which are derived by hydrolysis (enzymatic or via dilute mineral acids) of corn starch. In addition a series of thickeners were evaluated. The control magnesium chloride solution was prepared from the hexahydrate in Table 7 below which shows the results obtained. Again all samples contained 15% by weight of magnesium chloride.
The Maltodextrin DE15 exhibits good results due to the lower molecular weight, the less the influence upon freezing point. Some thickeners were unstable in the presence of magnesium chloride e.g. carboxy methyl cellulose, and so lose their efficacy as thickeners.
It is also important to define the chloride salt content for deicing/anti-icing liquids, the higher the chloride salt content, the lower the freezing point and the higher the ice melting characteristics. These characteristics are shown by the data in Table 8 below for Mg Cl2 and Ca Cl2 at varying salt and carbohydrate concentrations.
As the concentrations of salts and carbohydrates increase the freezing point of the mixtures decrease. In the case of calcium chloride at a fixed carbohydrate concentration of 4.1% an increase of 2.5% by weight of Ca Cl2 decreased the freezing point by 4.8xc2x0 F. (2.67xc2x0 C.). Again formulations can be varied to suit local conditions. Care must be taken as salt concentrations approach the eutectic point on the freezing pointxe2x80x94concentration curve where the freezing point can rise and the salt can crystallize out.
From the above discussion and laboratory evaluations the basic composition consists of at least the first two of the following components in aqueous solution depending upon ambient weather conditions, terrain, nature and amount of freezing/snow precipitation, environmental concerns, etc:
(1) An inorganic freezing point depressant in the form of inorganic electrolytes, mainly chlorides, but also others, such as sulfates and acetates, and could be used in concentrations of about 5 to 35 wt %. The main types employed are magnesium chloride, calcium chloride and sodium chloride.
(2) A carbohydrate, especially lower molecular weight carbohydrates in a range of about 180 to 1500. A preferred range is about 180 to 1,000. The carbohydrates can be obtained primarily from a wide range of agricultural based products such as those derived from corn, wheat, barley, oats, sugar cane, sugar beet, etc.
(3) Thickeners which are used in a concentration of about 0.15 to 10 wt % to increase the viscosity of the compositions so that the liquid remains in contact with the road surface or with the solid particles in piles of rock salt/sand, or rock salt/aggregates, or rock salt alone, or sand or aggregate. Thickeners are mainly cellulose derivatives such as methyl cellulose, hydroxy ethyl cellulose, hydroxy propyl methyl cellulose, hydroxy propyl cellulose, etc. or high molecular weight carbohydrates.
The corrosivity of deicing/anti-icing liquids is important due to the effect upon automobiles, other road transport vehicles, bridges, reinforcing rods (rebars) in concrete structures such as bridge decks, ramps and parking garage decks.
The testing of liquids for corrosivity can be quite complex and there are a number of tests developed by organizations such as ASTM and the National Association of Corrosion Engineers (NACE). The test conditions and metals must approximate those experienced in practice such as aerobic conditions and cold rolled steel specimens. Prior art tests using nails immersed in liquid contained in a screw top bottle are not meaningful mainly because of the anaerobic conditions and the variation in metal substrate composition, the degree of cold working and cleanliness.
Satisfactory test methods include SHRP H205.7 Test Method for Evaluation of Corrosive Effects of Deicing Chemicals or Metals (Handbook of Test Methods for Evaluating Chemical deicers SHRP-H332, Strategic Highway Research Program, National Research Council, Washington, D.C.) And the test described in the Deicer Specifications for the Pacific Northwest States of Idaho, Montana, Oregon, Washington. The latter is based upon the NACE Standard test Method for the Laboratory Corrosion Testing of Metals. TM0169-95.
Some corrosion rate results employing SHRP H205.7 showing corrosion inhibition due to carbohydrate presence are tabulated below in Table 9.
As can be seen from the data in Table 9, the carbohydrate magnesium chloride formulation reduces the corrosion rate of steel by 92.7% as compared to sodium chloride alone and 76.9% as compared to magnesium chloride alone. Formulations as shown in Examples III and IV (q.v.) were tested for corrosivity employing the Pacific Northwest States protocol and there was a reduction in the corrosion rate compared to sodium chloride solution of 57.2% for Example III and 40.4% for Example IV. This again shows corrosion inhibition properties.
The following examples are exemplary of various specific embodiments of the present invention which are useful as deicing agents:


An output beam from a laser is directed into an acousto-optic cell. The laser beam includes repeated sequences of two or more pulses. The acousto-optic cell is sequentially driven by RF voltages at two or more frequencies. A portion of the laser output beam is diffracted by the acousto-optic cell at two or more different angles to the laser output beam. This provides two or more secondary beams. One of the secondary beams includes only the first pulses of the sequences; the other includes only the second pulses of the sequences. The duration of the pulses in the laser beam is controlled to control time-averaged power in the secondary beams.

Laser applications often require a work piece to be irradiated with two or more individually controlled laser beams. Prior art methods of providing such a plurality of individually controlled laser beams have involved the use of arrays of beamsplitters including polarization-sensitive beamsplitters and polarization rotators. Using such beam splitter arrays together with separate modulators or controllers, while less costly than using a separate lasers for each required laser beam, may still prove prohibitively expensive, depending on a particular application.
Another method involves dividing a beam using an acousto-optic deflector powered at a number of different frequencies equal to the number of beams desired. This method is described in U.S. Pat. No. 7,003,003 assigned to the assignee of the present invention and the complete disclosure of which is hereby incorporated by reference. An abbreviated description of the method disclosed in the '003 patent is set forth below with reference to FIG. 1.
FIG. 1 schematically depicts beam-dividing apparatus 10 in which there are laser beam paths and connections between electronic and electrical components. Beam paths are depicted by fine lines, and electrical connections are depicted by bold lines. Apparatus 10 includes a carbon dioxide laser CO2 laser 12 including an RF power supply (not shown). A CO2 laser can provide an output beam having a wavelength between about 9 and 11 micrometers (μm). A controller 14 controls the output power of the laser and commands the RF power supply to operate the laser in a selected mode such as continuous wave (CW) or pulsed mode. Laser 10 delivers an output beam 16. Beam 16 is directed by turning mirrors 18 and 20 into an acousto-optic cell 22. One preferred acousto-optic cell is a model AGD-406 available from IntraAction Corporation of Bellwood, Ill. Such an AO-cell is generally referred to as a broadband AO-cell. Broadband AO-cells are designed to maintain the Bragg relationship (see below) over the entire bandwidth of the device. This allows the cell to be simultaneously driven at a plurality of different RF frequencies and provides minimal variation of the diffraction intensity, for example, less than about 10%, across a wide range of possible diffraction angles.
In apparatus 10, AO-cell 22 is driven by RF voltages at four different RF frequencies, f1, f2, f3, and f4, within the bandwidth of the AO-cell. Each driving frequency deflects a portion of output beam 16 at a particular angle depending on the frequency. The power in each diffracted portion (diffracted beam or secondary beam) is dependent, inter alia, on the power in beam 16 and the magnitude of the driving frequency, i.e., the magnitude of the RF voltage at that driving frequency. The diffraction angle (the Bragg angle) is given by the Bragg relationship:Sin θBn=λ0fn/2N0Va  (1)where θBn is the Bragg angle for frequency fn, fn is the driving frequency; λ0 is the laser beam wavelength; N0 is the refractive index of the acousto-optic cell material at wavelength λ0; and Va is the acoustic velocity in the cell material. In this example, the diffracting material of the cell is germanium (Ge), which is transparent for output wavelengths of the CO2 laser. Those skilled in the art will recognize that other laser wavelengths may require a cell having a different diffracting material.
Acoustic waves propagated in the acousto-optic material of the AO-cell by the driving frequencies generate optical phase gratings (not shown) within the acousto-optic material, through which laser output beam 16 passes. The angular (frequency) resolution of AO-cell depends, inter alia, on the size of beam 16 at the AO-cell and the driving frequencies. Beam-size is adjustable by a telescope or beam expander 24. Alternatively, the driving frequencies can be varied, to increase or decrease the spacing of the phase gratings.
In apparatus 10, driving frequencies for the acousto-optic cell are generated by four individual RF oscillators, designated f1, f2, f3, and f4 corresponding to the frequencies that are generated thereby. The RF voltage outputs of oscillators f1, f2, f3, and f4 are amplified by variable gain amplifiers A1, A2, A3, and A4, respectively. Driving AO-cell 22 with four frequencies provides four diffracted beams designated B1, B2, B3, and B4 corresponding to the driving frequencies. An undiffracted portion 16R of beam 16 is absorbed by a beam dump 26. The diffracted beams are directed by turning mirrors 27 and 28 into a folded optical path that is long enough to achieve a desired spatial separation of the beams. Once the beam separation is adequate, the beams can be focused by lenses 30 directly onto a workpiece. A beamsplitter 32 directs a sample of each beam to an individual detector to provide a measure of power in the beam. The samples are designated S1, S2, S3, and S4 corresponding to beams B1, B2, B3, and B4. Detectors are designated D1, D2, D3, and D4 corresponding to beams B1, B2, B3, and B4.
The detectors and associated circuitry 34 monitor power of each of the diffracted beams. The detector outputs are compared by a processor 36 against four input reference voltage signals provided by processor 36 in response to commands C1, C2, C3, and C4, corresponding to beams B1, B2, B3, and B4. The commands provided to the processor establish the desired amount of optical power in each of the beams. The reference voltage signals are representative of that desired power. Comparison of the reference voltages and the detector outputs provides gain commands G1, G2, G3, and G4 to amplifiers A1, A2, A3, and A4 respectively. The gain commands provide that the amplifiers increase or decrease the power of driving frequencies f1, f2, f3, and f4. There are, in effect, four control loops designated L1, L2, L3, and L4 corresponding to the four beams B1, B2, B3, and B4, respectively. The amplitude of each of the four beams B1, B2, B3, and B4 can be independently adjusted by varying the gain and accordingly the RF output voltage of amplifiers A1, A2, A3 and A4 respectively.
When the power of one of beams B1, B2, B3, and B4 is changed, absent any other action, power in the other beams will change because all of the beams share a common input (beam 16). This can be defined as a cross coupling between the beams. By way of example, if a voltage at one driving frequency is increased to diffract more light out laser beam 16 into a corresponding secondary beam, then power in the other three beams will be correspondingly reduced. An effect of this is that processor 36, particularly if control loops L1, L2, L3, and L4 all have about the same bandwidth, can attempt to restore power to the other beams, thereby causing power in one or more of the beams to oscillate. One method of avoiding this oscillation is to program controller 36 such that if a change in power in one the beams is requested, processor 36 suspends control of the other beams, thereby avoiding a competition between the beams for available power. This method, of course, restricts controlled operation of the four beams to applications in which the beams are not required to be simultaneously controlled.
Controlling beams B1, B2, B3, and B4 compensates for the above-described cross coupling, in a way that will allow the beams to be simultaneously controlled, can be accomplished by cooperatively controlling the power in laser output beam 16. The output power of an RF excited CO2 laser, as exemplified here, can be conveniently controlled by pulse width modulating (PWM) at a constant repetition rate or by pulse repetition frequency (PRF) modulating the input RF power into the discharge at a constant pulse width. Processor 36 can be programmed to keep track of the total power required by all four beams and to command controller 14 via another control loop L5 to raise or lower the power in output beam 16 in response to a requested change in power, in one or more of beams B1, B2, B3, and B4. This allows the beams to be controlled simultaneously.
A deficiency of the above described apparatus is that it must be located close to a workpiece to facilitate beam-delivery. FIG. 2 depicts an alternative apparatus 40 that overcomes this deficiency. Only differences between and additions to apparatus 10 are described to avoid repetition. Only sufficient detail of the beam-dividing portion of the inventive apparatus is depicted to highlight details of the modification.
In apparatus 40, beamsplitter 32 of apparatus 10 has been removed. Individual focusing lenses 32 of apparatus 10 are replaced in apparatus 40 by a single lens 42. The focal length of the lens is selected, cooperative with the optical path distance from the lens from the AO-cell 22, such that diverging beams B1, B2, B3, and B4 propagate parallel to each other. In addition, the lens focuses the beams to a beam waist position at which are arranged proximal ends 44A of optical fibers 44. The spacing of the proximal ends corresponds to the spacing of the beams such that each beam is focused into a corresponding one of the optical fibers.
It should be noted that the term "single lens" as used in this description and the appended claims means only that one lens focuses all secondary beams into the optical fibers. The lens itself, while depicted in FIG. 2 as only a single optical element, may include two or more elements for aberration correction, as is known in the art.
Hollow core optical fibers 44 are held in grooves 46 in a support platform 48. Platform 48 is preferably made from aluminum, but can be made from other metallic materials or from dielectric materials. Fibers 44 can be referred to functionally as beam-spreading or beam-separating fibers. Fibers 44 are curved such that distal ends 44B thereof are separated from each other by a distance greater than proximal ends thereof are separated from each other. The distal ends are preferably separated from each other sufficiently to allow a male fiber connector 50 to be attached to each one, leaving sufficient space that a female connector can be easily attached to each one of the male connectors, as discussed below. The hollow core is required because of the long wavelength, for example greater than about 9.0 micrometers (μm) of radiation in the beam.
Hollow-core optical fibers 52 are provided for transporting the beams from the spreading fibers to the remote location of the workpiece (not shown). Proximal end 52A of each fiber has a female connector 54 thereon for attaching the fiber to male connector 50 of the corresponding spreading fiber. Beams are delivered from distal ends 52B of fibers 52 to the workpiece. Beamsplitters 56 send samples S1, S2, S3, and S4, one for each beam, to detectors D1, D2, D3, and D4 respectively. The detectors are cooperative with monitoring circuitry 34 as described above with reference to apparatus 10 of FIG. 1.
It is particularly important in the arrangement of the present invention that beam-power be monitored after leaving the transport fibers as depicted in FIG. 2 and not at the output of AO-cell 22 as is the case in apparatus 10 of FIG. 1. A reason for this is as follows.
Unlike solid-core fibers used for transporting radiation at wavelengths from the ultraviolet (UV) through the near infrared (NIR), hollow-core fibers are particularly susceptible to losses at curves in the fibers and relatively small changes in the curvature, even changes occasioned by vibration, can cause a significant change in loss. While the spreading fibers 44 can be maintained in a fixed curvature by grooves 46 in block 48, it will usually not be practical to constrain transport fibers 52 to prevent small changes in curvature. Accordingly, as it is important that power of the beams on the workpiece is controlled, it is important that power monitoring for control purposes occurs after each beam leaves distal end 52B of the corresponding transport fiber 52.
A disadvantage of both of the above-described apparatuses is that simultaneous delivery of the beams and the use of analog circuitry sets a limit on the precision and flexibility with which beam parameters such as power and energy can be controlled. It may be useful in certain applications to provide more precise control of such parameters.

Apparatus for providing multiple time-division multiplexed independently controllable pulsed beams from a single, pulsed laser output-beam


A cooling product, with a body with a size and shape conforming with the palate, preferably on two plate sides. The body is made of soft material and is filled with an agent which can store cold preferably in gel form, and is mounted on a holder in the form of a shank which prevents the body from being swallowed.

The present invention concerns a cooling device for use in the treatment of problems in swallowing caused, amongst other things, by cerebral palsy or stroke, wherein the device consists of a body made of soft material and filled with an agent which can store cold, preferably in gel form.
Patients suffering from, e.g., cerebral palsy usually have problems with swallowing, since their swallowing musculature is not as mobile as that of healthy people. The same problem occurs in stroke patients.
Cooling of the palate area has been shown to be an effective solution to problems in swallowing in these cases. Cooling is normally effected by using a metal spoon which is cooled down before being placed against the palate.
The use of a metal spoon has several drawbacks. First of all, the spoon is hard and does not conform to the shape of the palate, leading to inadequate cooling. In addition to this the spoon is warmed up quickly during use, since the metal has little xe2x80x9cthermal inertiaxe2x80x9d. In order to obtain a satisfactory result when using the spoon, one must have at one""s disposal several spoons, which are replaced as they become heated to body temperature. This represents much too great a demand on the nursing personnel, who are generally already overtaxed.
Another possible solution to the problem is to use an ice cube placed round a stick. In this case the problem is that the ice cube can fall off the stick, causing the patient to choke.
There are known devices for cooling body parts.
U.S. Pat. No. 4,389,122 discloses a device for use as a hot or cold compress. It comprises a mouthpiece provided with bags filled with a heat/cold storage medium. Even though the device fulfills the function of cooling specific parts of the oral cavity, it is not suitable for palate cooling. The reason is that it has to be adapted to a specific size of palate, i.e. several sizes must be available in store, it is uncomfortable to have in the mouth for long periods, and it is relatively complicated to manufacture and will therefore have a high sales prices. In addition, it is difficult to use in patients who have dental plates, tubes etc. in their mouths, since it may come into contact with the actual plate or its fixing means, causing displacement and discomfort.
U.S. Pat. No. 3,885,403 discloses a device of use as a cold or hot compress. The device comprises a plastic envelope with a gel which maintains a gel-like consistency over large temperature ranges. This compress is not suitable for use in cooling of the palate, since it has to be relatively large in order to avoid the risk of being swallowed, making it uncomfortable in use.
U.S. Pat. No. 5,267,862 discloses a device for treatment of sleep apnea. In connection with the manufacture of the device a dental tray with a handle is employed. The area of application of this device differs from the area of application of the invention. Moreover, the device cannot be moved in the mouth in order to cool different areas in it.
U.S. Pat. No. 5,320,114 discloses a device for fitting mouthguards. The device has a handle and a curved surface for fitting the mouthguard. The area of application of this device is not the same as for the invention.
U.S. Pat. No. 5,460,527 discloses another dental tray which will be employed for bleaching the teeth. The dental tray has a handle which is used for dipping the tray into boiling water and which is later removed. In the same way as for the device described in U.S. Pat. No. 4,983,222 this patent further concerns an object which is intended to be stationary in the mouth, and not a body which is to be moved freely.
As mentioned above, the said known solutions have several disadvantages, and are not satisfactory for use either on the part of the patient or the nurse.
The above-mentioned problems are solved in a novel and surprising manner with a cooling device in accordance with the invention. The device according to the invention comprises a body made of soft material and filled with an agent which can store cold, preferably in gel form. The device is characterized in that the body is designed in such a way that it can be moved in the oral cavity and in the lip area in order to cool one area at a time, that the body is symmetrical in relation to a median plane, and that it is mounted on a holder in the form of a shank which prevents the body from being swallowed.
By means of the invention parts of the mouth can be cooled in a simple and satisfactory manner.
In one possible embodiment of the invention the cooling body can be divided in two by a central plate, and the plate can be heat-insulating, with the result that when one side of the device has become warm, it can be turned and the other side can be used.
The addition of a holder leads to a substantial reduction in the risk of swallowing the device. This in turn permits the cooling body to be made in a relatively small size. The advantages of a small cooling body are, amongst other things, that it is more comfortable to have in the mouth and that it will not necessarily come into contact with dental plates, or any probes in the mouth, etc. Another advantage of a small cooling body is that it is not necessary to adapt it to different palate sizes and shapes, since the cooling body will. only be in contact with part of the palate, and not the entire palate. Thus it is sufficient to manufacture the device in two sizes, one for children and one for adults.
The holder for the body may be attached to a ring round the cooling body, the ring providing the body with a certain rigidity which makes the device simpler to use. It may also be attached to said central plate.


A system for controlling a load circuit is disclosed. The system includes a plurality of multi-way sensor switches for mounting in an electrical boxes and coupling to the load circuit. Preferably, each of the multi-way sensor switches includes a tactile switch for manually opening and closing the load circuit load circuit, a built-in sensor for automatically opening and closing the load circuit in response to a level of detected motion and a micro-processor for generating status signals. The status signals are transmitted between each of the multi-way sensor switches over a traveler wire that is electrically coupled to each of the multi-way sensor switches. The micro-processor then uses the status signals to synchronize the operation of each of the multi-way sensor switches to allowing the multi-way sensor switches to operate in a true three-way fashion.

A number of different light management systems are known. One type of light management system utilizes a motion detector or sensor. In such systems, room lights are turned off, turned on and/or are dimmed according to a detected level of motion within the room.
There is a continual push to reduce energy consumption, because of rising energy costs and negative environmental impacts of energy usage and energy generation. Therefore, there is a need for improved light management systems, devices and methods which help to conserve energy.

This patent is subject to a terminal disclaimer.


An exercise device is provided which includes a surface for supporting a body of a user and a frame(s) for supporting the surface(s) above a floor. Resistance device(s) are connected to the device for providing resistance to movement of the user. A mechanism(s) may be provided for changing the orientation of the surface relative to the floor during an exercise routine. Also mechanism(s) may be provided for changing the orientation of the resistance devise(s) relative to the floor during an exercise routine. And mechanism(s) may be provided for changing the orientation of the surface(s) and the resistance devise(s) relative to the floor and to each other during an exercise routine. The resistance devise(s) may include component(s) for converting user motion into energy, electricity, etc. to power the exercise devise. Display device(s) may be provided to display various information relating to an exercise routine(s) to the user and to other(s). Computer control(s) may be included for controlling the amount of resistance provided by the resistance device(s) and for controlling the orientation of the support surface(s) relative to the floor and to hip extension and flexion. Memory device(s) may be associated with the computer control for storing exercise routine(s), recording the results of performed exercise routines and other information. Input device(s) may be provided with the computer control for user input information and output device(s) may also be associated with the computer control for outputting the results of performed exercise routine(s) and other information.

The present invention relates to exercise devices and in particular, to a computer controlled exercise device, an exercise device which supports a user""s body and which support can be rotated to various inclined positions and may be interchangeable to allow varying degrees of hip flexion and extension and may allow varying positions of a user""s arms, an exercise device that allows the user to generate energy to power said exercise device.
Exercise devices, machines, etc. are well known and include bicycle and bicycle type devices, machines, etc. treadmills, running, climbing, stepping, rowing, cross country skiing, elliptical, hybrids of motions, machines, etc. Many of these devices have controls for varying a resistance of the part engaged by the user as well as some type of display device for providing information to the user. For example, U.S. Pat. No. 4,613,129 discloses an exercise bicycle which includes a visual display unit and an electronic control which displays programmed exercise routines as well as displaying time, load or resistance applied to the user, speed of exercise by the user and user""s pulse rate. The automatic program mode of operation may provide routine such as simulating riding of the bicycle up and down hilly terrain only by varying the resistance of the pedals and visually displaying an increase on a visual graph.
U.S. Pat. No. 5,853,351 discloses an exercise devise that adjust a workload according to heart rate and correlating with a formula based upon the user""s heart rate, age, gender, weight, height, etc. This is all that it allows for and does not does not allow for mechanical configurations that benefit the user nor does it utilize self generated energy to power the devise.
U.S. Pat. No. 5,785,631 discloses an exercise apparatus that includes a support surface for a user, a display, and a computer control that controls resistance load and the orientation of the support surface for the user relative to the floor. The support surface does not allow orientation of the upper and lower body to adjust relative to themselves thus allowing variations of hip flexion and extension other than the amount necessary to move the resistance device provided for. Nor does it provide for a user generating system that has the capacity to provide energy to power the components that require power.
U.S. Pat. No. 5,685,804 discloses an exercise devise that allows a user""s feet to travel along an elliptical path of travel. The path of travel""s angle can be altered so that the stepping motion as claimed may resemble similarities of cross country skiing, walking, jogging, stepping, running, climbing. The devise does not allow for any additional support for the user other than the feet of the user. It only angle that the feet of the user travels on to adjust and does not allow the users body to change from an upright/horizontal position to a vertical position. Nor does it provide for the user""s movement against the exercise devise to self generate the electrical energy requirement to power the exercise devise.
U.S. Pat. No. 5,054,774 discloses an exercising machine useable by a wide variety of persons in which exercise routines can be pre-programmed for individuals and results of each individual""s exercise output can be displayed and stored on computer memory. An upper body support can be positioned either in a horizontal position or in an upright position.
U.S. Pat. No. 4,938,474 discloses an exercise apparatus which simulates stair climbing and determines the amount of exercise based upon the speed of a flywheel. The speed of the flywheel is controlled by a motor and sensor to determine the amount of exercise. This system does not allow for the user generating an amount of energy to provide power for the exercise device.
U.S. Pat. No. 4,372,551 discloses a stress table with a resistance device attached thereto in which the body support member and resistance device can pivot between vertical and horizontal to allow the user to exercise throughout a range of angled orientations. No display device is provided, nor is there any ability to provide a computer controlled exercise routine.
U.S. Pat. No. 4,358,105 discloses an exercise apparatus of the type that provides automatically controlled resistance levels that are unpredictable by the user.
U.S. Pat. No. 3,675,640 discloses an exercise apparatus in which a pre-programmed load is provided to an exercise device used by a user and the results of the user""s exercise efforts and including various physiological parameters of the user such as heart rate and rhythm, blood pressure, respiratory volume and rate are measured and stored.
In an embodiment, the present invention provides an exercise device which may include a surface for supporting a body of a user. The surface is supported above a floor by a unitary or multiple piece frame. The surface may also be mounted to the frame in such a manner so that it can change orientation relative to the floor during an exercise routine. For example, the surface may pivot forward and backward so that an angle of inclination of the back rest and seat surface relative to the floor and to the resistance means may change between horizontal, vertical and forward beyond vertical. In anther embodiment the resistance devise may be mounted to the frame in such a manner that the orientation of the resistance devise(s) can change relative to the floor and to the back rest and seat support surface. Also the back rest, seat surface, hand grips and the resistance means can change orientation in relation to each other and to the floor if so equipped, independently and or in any combo thereof. The surface may also pivot or rotate side to side about a horizontal axis or rotate up to 360 degrees or more about a vertical axis either while the surface remains horizontal or while the surface is also pivoting about a horizontal axis. And in another embodiment the orientation of the graspable support system may be adjusted to allow for changes in positions. Appropriate mechanical arrangements can be provided to allow the orientation change, such as worm gears, planetary gears, hydraulic actuators, etc. The orientation changing device could be manually operated or could be automatically controlled through an electric motor, hydraulic pump, etc. Such a unit provides physiological as well as psychological benefits.
In another embodiment, the invention provides an exercise device which is capable of being computer controlled via an integral computer, or from a separate computer via instructions received from a magnetic card, disk, direct or indirect connection to a computer via modem or similar arrangements. The computer control will provide instructions to the exercise device to control the operation of the device, such as varying the resistance provided, automatically changing the orientation of the support surface, the resistance means, if available, displaying information to the user, varying time durations for resistance levels and orientation positions, etc. to provide an infinite variety of duration, resistance and orientation combinations. Further, the computer control may control memory devices so that the operation of the user may be recorded, either locally or at a remote site via modem, wired or wireless transmission, as well as displaying the results of the user""s actions. Various types of information relating to the use can be recorded such as date and time of use, duration of use, functions perform, energy expended by the user, heart rate at select intervals, blood pressure, respiration rates, etc. Many types of information, physiological, etc. whether recorded or not relating to the use such as energy expended by the user, heart rate at select intervals, blood pressure, respiration rates, etc. can be used via the computer to control the functions of the exercise. The computer may use physiological response from the user during the workout to control the functions of the exercise devise in real time. In fact, a large number of parameters relating to the user""s exercise use can be used for controlling the exercise devise and or to be recorded as the exercise is performed so that the user, a coach or trainer, or a cardiac therapist, medical personal, or others will be able, through appropriate software and other means available, to view the entire exercise program, or parts or summaries thereof, and compare it to other workouts or to pre-programmed workouts and calculate or re-calculate workouts based upon parameters contained in the software for programming future exercise workouts etc.
A resistance device, could be engageable by the user and associated with the frame, is built into the unit to provide resistance to movement of the user such as at least leg or arm movement. For example, a bicycle pedal arrangement could be provided for leg resistance, rotatable cranks for arm resistance or pivoting or sliding devices for arm, leg or back engagement. Many types of resistance devices, components are known such as pivoting devices, sliding devices, weights on cables or levers, braking motors, generators, brushless generators, eddy current systems, magnetic systems, alternators, tightenable belts, friction rollers, etc. and could be substituted in the devices illustrated while still being within the scope of the present invention. The resistance devices may be adjusted manually, manually through electrical switches, or by means of a computer type control as described below.
Energy provided for the exercise device may be provided by one or more of the following; user generated with movement provided by the user against said resistance device, external power supply or supplies such as electrical outlets, batteries, etc. and in any combo thereof. The energy may provide the necessary power, electricity, etc. to supply all of the components that utilize energy, such components may include but are not limited to the displays, resistance devices, means for changing orientation, batteries, video games, controls, etc. This energy could be used to power all of the electronics that comprise the electronics of the exercise devise.
In an preferred embodiment the resistance devise would comprise of a generator type motor that when moved by the user produces energy, electricity, etc. which supplies the exercise devise. Thus eliminating the need for an outside source of energy, such as an electrical outlet, etc.
Also provided is a display device, which may be a cathode ray tube, liquid crystal display, series of LED""s or other appropriate display units for displaying selected information relating to use of the device to the user. The information displayed could include a predetermined exercise program to be followed by the user, the results of the movement of the user against the resistance device and/or various monitored physiological parameters of the user such as pulse rate, respiration rate, blood pressure, etc. The display would also show set up information as well as information input by the user through an appropriate input device.
Preferably the device includes a computer-type control with one or more microprocessors for controlling the level of resistance applied by the resistance device either in response to user input resistance levels or a pre-programmed exercise routine and or via physiological response. Thus the control will be connected to a memory device and will also be connected to the display device and the resistance device.
In a preferred embodiment of the invention the control will also control a device for varying the orientation of the support surfaces of the back rest and seat, the orientation of the resistance means, the graspable support system or a combo thereof so that the attitude of the user and or the degrees of hip flexion and extension may vary during the exercise routine in accordance with a pre-programmed exercise routine or user input selections and or via physiological response.
For example, if the exercise device includes a bicycle pedal resistance device and or a graspable handle resistance device, the orientation of the support surface and or the orientation of the resistance means can vary during the exercise routine to simulate an upright bike, a recumbent bike, and or a rowing-cycling-climbing like arm motion and or a in any varying combination thereof going uphill, level, and going downhill in conjunction with varying resistance levels at the resistance device(s). Also, by pivoting side to side and about a vertical axis will allow the exercise device to simulate turns, both on level ground and in conjunction with simulated hills. Not only will this provide additional user interest in the use of the exercise device, Applicant believes that psychological and physiological benefits result from exercise being performed at different orientations relative to a vertical and varying degrees of hip flexion and extension, due to the varying effects of gravity and hip angularity on the exercise being performed. Interactive games or videos, displayed on the display devise and controlled thru various input devises, including buttons spaced away from the display devise, can be played which would cause changes to the duration, resistance and orientation of the support, etc. as the game or video progresses.
Preferably the results of the exercise routine performed by the user are stored on memory, either on a non-removable hard disk type of memory or to individual floppy disks or magnetic cards which can be removed from the exercise device for further use, such as comparison to subsequent exercise routines performed by the user or for review by appropriate trainers, medical or therapy personnel. The exercise device may also include a remote transmission device such as a modem so that the results of the exercise routine can be transmitted to a remote location by either real time transmission as the exercise routine is being performed for optionally monitoring at a remote location or after the exercise routine has been completed, and other pre-programmed exercise routines can be transmitted to the exercise device for use by a user.


An environmental sampler for a mass spectrometer is disclosed that provides for controlled introduction of small amounts of fluids or gases into the vacuum system of the mass spectrometer under severe environmental conditions. Accurate calibration checks of the environmental sampler and mass spectrometer during remote autonomous operation is possible by means of an internal standard reservoir integral with the environmental sampler.

1. Field of the Invention
The present invention relates generally to sampling systems for mass spectrometers and, more specifically, to an environmental sampler for a mass spectrometer that allows for controlled introduction of small amounts of fluids or gases into the vacuum system of the mass spectrometer under severe environmental conditions. Accurate calibration checks of the sampler and mass spectrometer during remote autonomous operation is possible by means of an internal standard reservoir integral with the sampler of the present invention. A computer-controlled stepper motor moves a rod set which samples the external sample and the internal standard alternatively.
The forward motion of the rods (toward the outside of the pressure/vacuum housing) in predetermined numbers of steps samples the internal standard reservoir while the reverse motion of the rods (toward the inside of the pressure housing) samples the external environment. The standard reservoir is designed to be at the same pressure as the external sample. This configuration provides a pressure-compensated rod set, reducing the mechanical forces on the stepper motor. This configuration also ensures a constant ratio of sample to standard volume and mass (approximately one to one). Hydraulic seals and O-rings keep external fluids and gases from entering the sampler, wherein surface-bound fluids and dissolved gases are evaporated from the sampler rod into the vacuum system. Dry gases (e.g. low moisture air) enter the sampler via small calibrated leaks in the rod during movement.
Initially, the sampler is mass spectrometer leak tight (no detectable flow). Flow into the sampler vacuum chamber is accomplished by engineering small calibrated leaks in the rod/seal system thereby permitting extremely small amounts of sample to be repeatedly and reliably introduced into the vacuum system of the mass spectrometer as the rods travel back and forth. This small sample capability reduces the pumping load on the vacuum system and permits extended in situ operation by virtue of its low power consumption. Its operational pressure range (less than one atmosphere to greater than 400 atmospheres) allows autonomous operation in a variety of earth and planetary environments (outer space to full-ocean water depths).
A unique feature of the invention is the very small amount of sample acquired, which is rapidly expanded into a vapor prior to introduction to the mass spectrometer interface. Therefore, initial sample temperatures can be quite high without serious effect on the mass spectrometer. Temperature maximums are only dictated by the choice of polymers for the sampler seal and the plenum inlet hoses. Management of sample temperatures in excess of 200□C is possible if high temperature polymers such as silicon or teflon™ are used.
The present invention further includes a removeable external vacuum port to ambient that allows pumping and monitoring of a sample/standard waste vacuum within the mass spectrometer pressure housing. A removable external plenum allows directional flow of gas or fluid over the sampler rod pumped from a remote region of interest.
The present invention is primarily designed for a mass spectrometer, but it can be used in any application where small quantities of sample are needed from the environment, such as in gas or liquid chromatography, capillary electrophoresis, or any combination of these and other analytical techniques with mass spectroscopy.
2. Description of the Prior Art
There are other samplers for mass spectrometers. Typical of these is U.S. Pat. No. 4,201,913 issued to Bursack et al. on May 6, 1980.
Another patent was issued to Cassidy et al. on Jun. 7 1983 as U.S. Pat. No. 4,386,852. Yet another U.S. Pat. No. 4,562,351 was issued to Atherton et al. on Dec. 31, 1985 and still yet another was issued on May 20, 1986 to Gilles et al. as U.S. Pat. No. 4,590,165.
Another patent was issued to Whistler on Jul. 22, 1986 as U.S. Pat. No. 4,601,211. Yet another U.S. Pat. No. 4,879,458 was issued to Brunfeldt et al. on Nov. 7, 1989. Another was issued to Spraul et al. on Mar. 14, 1995 as U.S. Pat. No. 5,397,989 and still yet another was issued on Jan. 6, 1998 to Haner et al. as U.S. Pat. No. 5,705,928.
Another patent was issued to Holle et al. on Nov. 24, 1998 as U.S. Pat. No. 5,841,136. Yet another U.S. Pat. No. 6,177,991 was issued to Okuda on Jan. 23, 2001. Another was issued to Kenny et al. on Feb. 13, 2001 as U.S. Pat. No. 6,186,012 and still yet another was issued on Feb. 20, 2001 to Hirabayashi et al. U.S. Pat. No. 6,190,316.
An apparatus for introducing a gaseous sample into a mass spectrometer is disclosed which includes a hollow antechamber or cavity disposed between the sample stream and the high vacuum enclosure. Orifice openings are provided in the antechamber which allow the antechamber to communicate both with the high vacuum enclosure and the sample stream. An electrically operated pulsed valve is used to admit a series of small volumes of sample by pulses of controlled duration and frequency such that the sample flow from the antechamber into the high vacuum enclosure can be made to resemble one of essentially constant flow.
A phase synchronization apparatus useful for synchronizing the sample signal and the demodulation signal at a spectrometer includes a stepper motor the position of which is controlled so that the desired phase synchronization is ensured.
The invention consists of a mass spectrometer having a sample insertion probe on which a reference compound and an unknown sample can be simultaneously introduced without mixing into a field ionization or ion or neutral particle bombardment ion source. An insulated support is mounted by a parallel hinge on the end of the probe shaft. Two or more separated segments or emitter wires, one carrying the unknown sample, another carrying an appropriate reference compound, are mounted on a base member which is fitted to the support. A drive shaft, concentric with the outer probe shaft, has an eccentric peg on the end, which engages with a cam on the support, so that rotation of the drive shaft results in an oscillating motion of the segments or emitters, alternately positioning them in the optimum position for ionization. A spectrum of the sample or the reference compound can be obtained when required by selecting the appropriate position of the drive shaft. Rotation of the drive shaft may be controlled by a servo-mechanism and a computer. As a result, improved accuracy of mass measurement of peaks in the mass spectrum of the sample is achieved.
An automatic sampling method for introducing a diluted viscous sample into an instrument for analysis for trace elements. The automatic sampling system includes a tube assembly, a member for mounting the tube assembly in proper relation, means for maintaining, between sampling, the free end of the tube assembly in a cleaning solution, and means for inserting the free end of the tube assembly into a sample contained within a container. Preferably, the instrument is a spectrometer, the samples are organic and aqueous samples, such as oils, brines, sludges, plating solutions and the like, and the trace elements include wear metals and also other elements, such as calcium, barium, zinc, sodium, magnesium, boron, phosphor and the like.
A multi-port valve uses a flexible sample tube to selectively intercept gases flowing from inlet ports into a common manifold space. The manifold space is placed under sufficient vacuum to insure that gas samples will be selectively received by the sample tube when the sample tube is placed in close proximity to the selected inlet port to be sampled. The sample tube is arranged so that gases to be sampled from the selected port wash over the entrance end of the sample tube so that contaminated or mixed gases from the manifold space are prevented from entering the sample tube. The sample tube is mounted to pivot inside a valve body and is moved by a sample tube guide which rotates inside the valve body to selectively align the sample tube with the inlet ports. The valve body may be sealed by a cover through which the valve guide is driven to rotate by a magnetic coupling, or by a bearing seal through which the sample tube guide projects. The sample guide may be rotated in a stepwise fashion by a stepper motor for slow collection rates, or may be rotated quickly by a motor for rapid sampling. Magnetic detectors or a shaft decoder may be used to monitor the position of the sample tube guide. The multi-port valve may be used in a system in which a measuring device such as a mass spectrometer and a data system are used.
An automated sample inlet system for sequentially introducing a plurality of indium encapsulated samples into a mass spectrometer wherein the samples are placed in a micro tube and loaded into a circular carousel under a vacuum bell jar maintained at ambient temperature. The samples are systematically advanced by rotating the carousel resulting in each sample sequentially falling through a delivery tube containing an inverted ball valve into a sample vaporizing chamber within an oven. An additional pair of sapphire ball valves in communication with the glass vaporizing chamber are sequentially opened and closed in a preprogrammed manner along with the opening and closing of the thermal inverted ball valve and the indexing of the carousel such as to automatically evacuate the glass inlet system within the oven, introduce a new sample and vaporize it and then inject this vapor into a mass spectrometer. Such a system is useful in running large numbers of mass spectrometer analyses of hydrocarbon liquids and the like.
An NMR spectrometer (10) for the measurement of liquid samples having a probe head (20) exhibiting an upper and a lower support (21 or 22), a connector (5) for a feed conduit (15) for the introduction of a liquid sample (1) into the spectrometer (10) and a connector (6) for a drain conduit (16) for the drainage of the liquid sample (1) out of the spectrometer (10), a sample tube (3), arranged between the upper and the lower supports (21 or 22), for the acceptance of the fluid sample (1), whereby the one end of the sample tube (3) is connected to the connector (5) for the feed conduit (15) and the other end to the connector (6) for the drain conduit (16), exhibits, coaxially to the sample tube (3) a further tube (4) for the acceptance of a calibration fluid (2) which, on one end, is connected to an additional connector (7) for a feed conduit (17) to introduce the calibration fluid (2) into the spectrometer (10) and, on its other end, to an additional connector (8) for a drain conduit (18) to drain the calibration fluid (2) out of the spectrometer (10). In this manner, it is possible to measure the sample fluid (1) in a simple fashion, without the previous mixing of additives and, subsequent to the measurement, to regain the sample fluid in its original state, while allowing for the introduction of a calibration fluid (2) for field stabilization and for the quantitative comparison of line intensities.
A sample delivery system for a flow-through NMR analysis is provided, which utilizes pressurized gas as a means for conveying a sample into and out of an NMR spectrometer. Two sources of gas pressure, a forward pressure and back pressure, oppose the sample within the tubing of the sample delivery system and the tubing of the flow-through system which are operatively coupled together. Conveyance of the sample in any direction within the tubing is achieved by adjusting the pressure differential. Precise positioning of the sample in the magnetic field center and complete removal of the sample from the NMR spectrometer when analysis is complete are achieved by using a signal processor which receives signals from the NMR detector or other detectors positioned along the length of the tubing. These signals provide an indication of the position of the sample in the tubing. The signal processor uses this information to adjust the forward and the back pressure, thereby achieving the desired positioning of the sample.
A system and a method for the introduction of sample supports, which hold large numbers of analysis samples, into the ion source region of a mass spectrometer. The sample supports are especially intended for the ionization method using matrix-assisted desorption through laser bombardment (MALDI). The system consists of using an evacuable, sealable and removable cassette which, instead of using a through-passage lock chamber with two lock valves, can be attached in a simple manner to the entrance opening for the ion source of the mass spectrometer. Only the entrance opening has a lock valve, and the expensive second lock valve in the lock chamber is no longer needed. The cassette can also be used for protected transport and for storage of the sample supports, and in particular for storage of the samples under protective gas or vacuum.
A measuring device such as a spectrometer uses an automatic sample changer for carrying a plurality of samples. The automatic sample changer may include a rotary circular disk rotatable around its central shaft by a stepping motor for changing positions of the samples which are positioned in a circle around the central shaft of the disk. A memory device preliminarily storing control data for each of different kinds of automatic sample changers is provided. The automatic sample changer, when connected to a control unit in the main body, serves to receive control signals for controlling motions of the motor and to transmit data stored in the memory device through a connector. The main body of the measuring device contains a control unit which serves to read out the control data from the memory device, to use the received control data to generate the control signal and to transmit the generated control signal to the automatic sample changer.
A manipulator apparatus, system and method for measuring analyses present in sample tubes. The manipulator apparatus includes a housing having a central bore with an inlet end and outlet end; a plunger mechanism with at least a portion thereof slideably disposed for reciprocal movement within the central bore, the plunger mechanism having a tubular gas channel with an inlet end and an outlet end, the gas channel inlet end disposed in the same direction as said inlet end of the central bore, wherein the inlet end of said plunger mechanism is adapted for movement so as to expel a sample tube inserted in the bore at the outlet end of the housing, the inlet end of the plunger mechanism is adapted for connection to gas supply; a first seal is disposed in the housing for sealing between the central bore and the plunger mechanism; a second seal is disposed at the outlet end of the housing for sealing between the central bore and a sample tube; a holder mounted on the housing for holding the sample tube; and a biasing mechanism for returning the plunger mechanism to a starting position.
A living body fluid analyzing system includes a microdialysis for sending a first solution having an osmotic pressure which is substantially similar to a osmotic pressure of a body fluid into a living body and extracting a second solution from the living body. A first flow passage is provided in which the second solution from the microdialysis flows and a second flow passage is provided which mixes the second solution with an organic solution. Furthermore, there is provided a gas source and a gas flow controller which controls a flow quantity of the gas from the gas source and a third flow passage in which a gas introduced from the gas source flows. An ion source is provided having an orifice for spraying and ionizing the second solution from the second flow passage at an end of the third flow passage, and a mass spectrometer is provided for mass-analyzing the ions sprayed from the orifice.
While these mass spectrometer sampling devices may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described.

Environmental sampler for mass spectrometer


A computer-implemented method for protecting active copies of data may include detecting an attempt to access an active copy of original data, identifying an access rule associated with the original data, and determining whether to allow access to the active copy by applying the access rule to the attempt to access the active copy. The computer-implemented method may also include associating the access rule with a file-system path of the active copy. The access rule may be a file-system rule associated with a file-system path of the original data. Various other computer-implemented methods, systems, and computer-readable media for protecting active copies of data are also disclosed.

The WINDOWS volume snapshot service was first included in MICROSOFT's WINDOWS XP operating system. In WINDOWS XP, the volume snapshot service creates non-persistent (i.e., temporary) snapshots that MICROSOFT refers to as volume shadow copies. Volume shadow copies may facilitate creating backups by providing a point-in-time representation of a volume. Volume shadow copies may also alleviate problems associated with file locking.
In WINDOWS 2003 SERVER, MICROSOFT introduced a feature referred to as Shadow Copies for Shared Folders. Shadow Copies for Shared Folders may create periodic point-in-time copies (i.e., snapshots or shadow copies) of files on a shared network resource. WINDOWS VISTA includes a similar feature called Previous Versions. Previous Versions may create periodic snapshots that store copies of files on local volumes.
The shadow copies created by WINDOWS 2003 SERVER and WINDOWS VISTA may be particularly vulnerable to malicious access because they are persistent, rather than temporary, snapshots. Furthermore, the Shadow Copies for Shared Folders service in WINDOWS 2003 SERVER and the Previous Versions service in WINDOWS VISTA may be enabled by default. Thus, many computers running WINDOWS VISTA may store persistent shadow copies of the computers' volumes that may be directly accessible by any code running on the computers. Similarly, many networks with servers running WINDOWS 2003 SERVER may store persistent shadow copies of network resources that may be accessible to many network devices.
Traditional data protection systems may protect original data but may not protect the persistent shadow copies of the original data. Attackers who are unable to access the original data, may target the shadow copies. Thus, users may have a false sense of security because sensitive information in the original data may be protected, but the same sensitive information may be exposed and easily accessible through a snapshot.

Methods and systems for protecting active copies of data


A non-intrusive fluid level detector including a single point capacitive sensor mounted on the outside surface of a receptacle such that capacitive principles can be utilized to sense the level of a liquid contained within the receptacle. The sensor assembly is disposed in a substantially fixed position on the exterior wall of the receptacle wherein the dielectric effect of the liquid changes the effective capacitance of the sensing capacitor as the liquid rises and falls within the receptacle. This change in effective capacitance is detected by electronic circuitry included in the detector device. In one embodiment, the fluid level detector is directly mounted to a completely non-conductive receptacle. In another embodiment, the fluid level detector is mounted to a non-conductive window which is an integral part of a receptacle fabricated out of a conductive material.

Fluid level detectors which sense the level of a liquid contained within a receptacle are well known for use in conjunction with automotive engines. Historically, such detectors have been made in the form of float operated switches involving moving parts which are subject to friction and wear. Other devices utilize an electrical probe to detect fluid levels by measuring the conductivity of the coolant. However, these devices require complicated current amplifying systems because there is often an insufficient amount of current passing through the electrodes to power an indicator lamp. In either of these systems, the measuring sensor is located in the fluid where contaminants are likely to collect on the sensor and disturb the fluid level measurement. Furthermore, the devices in the prior art, as described, are categorized as "intrusive" in that they require an opening into the receptacle containing the fluid. This creates an additional potential for fluid leaks as well as potential deterioration of the sensing devices.
Due to the problems discussed above, it has become desirable to employ non-intrusive means to sense fluid levels contained in receptacles. These non-intrusive systems typically involve wave propagation techniques which are implemented through a transmitter/receiver system. Typically, these systems involve the transmission of an ultrasonic signal from a transmitting transducer through a fluid to a receiving transducer. Such ultrasonic transmission systems require a liquid transmission medium in order to carry the ultrasonic signal from the transmitting transducer to the receiving transducer. Lack of signal at the receiving transducer relates to a lack of liquid transmission medium, activating a no fluid present indication. However, a failure in the transducer pair or in their respective electronic connections results in a lack of signal from the receiving transducer which, in turn, activates the normal failure mode thereby falsely indicating a dry or no fluid present state.
The increasing importance of monitoring fluid levels in automotive and other applications is creating a need for more reliable non-intrusive fluid level sensors. It is, therefore, important that a fluid level detection system be developed which can provide reliable data and which does not require contact with the fluid being measured.