A process for producing high fructose corn syrup from glucose containing syrup, which entails isomerizing the glucose containing syrup through an enzymatic reaction to make high fructose corn syrup, wherein the enzymatic reaction occurs in a gas containing solution which comprises at least one gas selected from the group consisting of noble gas.

1. Field of the Invention
The present invention relates to a process for producing high fructose corn syrup from glucose using noble gases.
2. Description of the Background
Wild honey is the oldest sweetener known to man, however the use of cane sugar as a sweetener dates back at least 8,000 years to the South Pacific. The sweetness of cane sugar approximates that of honey.
It was determined in 1744 that the sugar isolated from sugar beets is identical to the sugar derived from sugar cane. Thereafter, sucrose, manufactured from cane or sugar beets, being much more abundant than honey, became the sweetener of commerce. This position remained unchallenged until the development of high fructose corn syrup, a corn sweetener.
The development of corn sweeteners dates to 1811, when it was discovered that starch yielded a sweet substance when heated with acid. It was not until 1940, however, that the discovery, isolation and application of various carbohydrase enzymes afforded many new corn syrups having a variety of syrup properties. See L. E. Coker and K. Venkatasubramanian (1985). Starch Conversion Processes. Ch. 29, M. Moo-Young (ed.) Comprehensive Biotechnology, Vol. 3, H. W. Blanch, S. Drew and D. I. C. Wang (eds.), Pergamon Press, New York, N.Y., pp. 777-787.
More recently, glucose isomerase, which converts glucose to its sweeter isomer, fructose, was commercially developed. In the wake of this development, the enzymatic transformation of glucose to fructose was first introduced to corn sweetener production in 1967. The first high fructose corn syrup, commonly referred to as HFCS, contained 15% fructose. The manufacturing process, known as isomerization, originally involved the direct addition of isomerase enzymes to a dextrose substrate and a batch reactor. Further process improvements afforded HFCS products containing 42 and 55% fructose. Many producers of HFCS now further concentrate the fructose, using a chromatographic technique, and supply the concentrated material as a sweetener. See Verhoff, F. H. et al (1985). Glucose Isomerase. Ch. 42, M. Moo-Young (ed.), Comprehensive Biotechnology, Vol. 3, H. W. Blanch, S. Drew and D. I. C. Wang (eds.), Pergamon Press, New York, N.Y., pp. 837-859.
HFCS is now the most widely used sweetener in beverages and is used as well in the bakery, dairy, and canned foods industries. As noted above, HFCS is produced from corn, and it the most popular of the corn sweeteners. Other corn syrups contain glucose and dextrose; however fructose is the sweetest isomer. Through a process called wet-milling, the starch from corn is converted into corn syrup, and this syrup is then filtered to extract a syrup of highly concentrated fructose. There are presently three types of HFCS commonly sold in the United States: HFCS-42, -55, and -90, representing the percentage of fructose in the mixture. HFCS-55 is manufactured by blending 42 and 90% fructose, and is the highest value and most used of the three.
HFCS is attractive as a substitute for sugar because it is generally lower-priced and sweeter, thus necessitating smaller input per unit of output. Although HFCS is a liquid of comparable sweetness to sugar, it has different physical properties. Thus, HFCS cannot substitute for sugar in all products. For instance, baked products require sugar to ensure proper browning and for texture; jams and jellies require sugar to gel properly.
The soft drink industry accounts for approximately 75% of the demand for HFCS in the U.S. each year. Of the HFCS types available, HFCS-55 accounts for the bulk of the HFCS use in the beverage industry, representing 95% of all caloric sweeteners used in beverages. The other major type, HFCS-42, is more commonly used in the baked goods and dairy industry as a substitute for sugar in products in which color and texture, or gelling properties, are not affected by HFCS. Because of its high concentration of fructose, HFCS-90 is used primarily in reduced calorie foods such as jams and jellies.
A crystalline form of fructose can be produced from HFCS, but until recently the commercial price of this form was not competitive with the other versions. However, a cheaper production process was introduced in 1987, and experimental production of this form is continuing. Most of the crystalline form is currently used as part of a sweetener blend. Crystalline fructose may become a substitute for sugar in some new products, but the market appears to be limited.
Because of its low cost, corn has become the primary raw material source of starch syrups and sugars, including HFCS. Corn is processed into starch through a method called wet milling. In addition to the production of starch, the initial raw material in the HFCS production process, the wet milling process produces several valuable by-products that can be sold by the miller for a profit as well. Thus, these by-products serve to enhance the attractiveness of HFCS production by lowering the final cost to the producer of HFCS. In addition to starch, the wet-mill process also produces 13 pounds of gluten feed (per bushel of corn used), 2.75 pounds of gluten meal, and 1.6 pounds of oil. In terms of percentage of output produced, starch (the HFCS precursor) is the primary product, representing 67.2% of the output from a bushel of corn. Feed accounts for 19.6% of output; germ (corn oil precursor), 7.5%; and meal, 5.7%.
Corn starch is the initial raw material in the HFCS production process. Through a series of four major processing stages, the starch is converted to 42% HFCS. The major stages are: (1) conversion of starch to dextrose feedstock; (2) preparation of high quality dextrose feedstock for isomerization; (3) isomerization of the feedstock to fructose, the major and most significant stage in the process; and (4) secondary refining of the fructose product. If required, a fifth stage can be added in which additional refining of the 42% solution can be used to produce 55% and 90% fructose syrups. A diagram of the conventional 5-stage process is given in FIG. 1. Each Stage from that figure is discussed below.
Stage 1: First Enzymatic Step: alpha-amylase. The first stage converts the starch slurry to dextrose. The starch slurry is initially a mixture of amylose (approx 15-30%) and amylopectin (approx 70-85%). Several steps are involved in the production of dextrose from starch. First, the starch slurry is subjected to a high temperature treatment in which the starch granules burst and the starch becomes gelatinized. This gelatinized starch is then thinned by both high temperature and hydrolysis by alpha-amylase. This step produces liquid, less viscous and lower molecular weight dextrin products. This step takes approximately 130 minutes.
Second Enzymatic Step: amyloglucosidase. Following this liquefication and dextrinization, the dextrin products are in turn subjected to stepwise hydrolysis by amyloglucosidase to form a glucose syrup. This is referred to as saccharification, a continuous process which can take as long as 75 hours, depending on the amount of enzyme present. The end result of the saccharification process is a high dextrose (94-96% dextrose) hydrolyzate that is further refined in Stage 2.
Stage 2: The dextrose from Stage 1 is refined to produce a high quality feedstock necessary for the isomerization process in Stage 3. The refining process reduces the impurities such as ash, metal ions, and proteins which can impair the efficiency of the isomerization enzyme in Stage 3. In the refining process, the dextrose is subjected to a series of filtration steps to remove protein and oil. Next, the color of the liquor is removed through a series of granulated carbon columns. Then, the liquor is subjected to an ion-exchange system in which it is deionized. Lastly, the liquor is evaporated to the proper level for the next stage and treated with magnesium ions to inhibit any calcium ions that may interfere with the isomerase activity in Stage 3.
Stage 3: Third Enzymatic Step: Glucose Isomerase. This stage, in which the dextrose liquor is isomerized to high fructose corn syrup, is the heart of the HFCS process.
The isomerization stage converts the glucose to a much sweeter, and thus more valuable, fructose product. The key development that makes this enhanced value possible is the commercial development of immobilized glucose isomerase, a bound enzyme which can withstand the elevated temperatures of the process. The cost of the isomerization enzymes is a significant part of the total operating cost of the HFCS process. Thus, much research effort has been devoted to the economics of the activity of the enzyme and especially the rate of its decay.
Use of immobilized enzyme reactor systems (vs batch reactions, with their much longer reaction times) is the common form in the industry. The critical variable in this stage is the activity of the enzyme, which controls the rate of conversion of dextrose to fructose and determines the quality and fructose content of the product. This is a functional property of the enzyme itself and is modified by reaction conditions. The activity of the enzyme decays through time in a relatively regular manner, and the reactor system is designed and operated to minimize the fluctuations in activity resulting from this decay. For instance, the flow of the dextrin is continuously adjusted so that the residence time of the dextrin can increase to match the reduction in enzyme activity to achieve a constant conversion level through time. In addition, parallel reactors are used to increase operational flexibility. In general, at least eight isocolumns are operated in parallel and independently of the others so that each column can be put on- or taken off-line as needed.
The activity of the enzyme system is usually characterized by what is referred to as a half life. The half life of the enzyme is the amount of time that is required for the enzyme activity to be reduced by half. The enzyme system is usually operated for at least two half-lives and then replaced. Variables affecting half-life of the enzyme, and thus replacement costs, include the allowable variance in flow, pH, salt concentrations, temperature, dry solids content, metal ion concentrations, required production capacity of the processor, the number of isocolumns in parallel, and the average decay rate of the individual columns. Indeed, the economics of the HFCS process is generally analyzed in terms of costs per pound of enzyme utilized. The physical properties of the enzyme system determine its productivity and its half-life; these two parameters in turn affect the size of the reactor necessary to produce the desired conversion level and throughput of HFCS.
In general, HFCS producers seek to reach an optimal operation condition across several parameters including enzyme longevity and activity, flow rate and temperature.
The glucose isomerase system is the largest volume use of an immobilized enzyme in the Unites States. There are a number of commercial suppliers of the isomerization system.
Many of the suppliers sell fixed whole cells with isomerase activity, although other suppliers sell different immobilized forms, or a pure, isolated enzyme system. The enzyme system is used within the plant in a packed-bed reactor consisting of parallel columns of enzyme material. Most catalysts/enzyme systems are in particulate form (dry pellets). The systems available commercially vary as to the organism from which the isomerase is derived, the immobilization carrier, and the binding procedures used by the producer.
The most important variables affecting the design of a reactor system, and thus the productivity of the isomerization process include the enzyme loading factor, catalyst packing density, operational stability of the catalyst, or reactor half-life, transport efficiencies, enzyme contact and residence time.
The enzyme loading factor refers to the amount of enzyme (and thus catalytic activity) present in the immobilization system. This factor is influenced primarily by the immobilization process used to produce the enzyme system, and is determined by the enzyme producer. Load factor varies according to the relative amount of cells present, if the system is a fixed cell system, and the extent of enzyme inactivation, or loss of activity through the various enzyme preparation stages.
Catalyst packing density refers to the amount of enzyme complex present per unit volume of reactor. This is influenced in part by such variables as pressure and reactor configuration, whether linear bed or spiral.
Reactor half-life, the amount of time required to reduce the enzyme activity by half, depends on such factors as the bacteria or the organism used to produce the enzyme, and is also primarily a function of the particular enzyme system purchased.
Transport efficiency involves the rate of flow of substrate through the membrane system. Since it can be slower than the reaction time itself, the transport time of the substrate can greatly affect overall productivity.
Finally, enzyme contact and residence time, which contribute to the efficiency with which the enzyme operates on the substrate, is a function of reactor design (e.g., column size and flow rates).
Stage 3 can take as long as 4 hours.
Because of the biochemical kinetics of the conversion process, the primary product of Stage 3 is a 42% HFCS solution, which contains as well 52% unconverted dextrose, and 6% oligosaccharides. Further processing of the HFCS solution involves secondary refining of the 42% portion in Stage 4.
Stage 4: Color and ash are removed from the 42% HFCS through carbon filtration and ion-exchange systems. Stage 4 can also involve evaporation of the 42% solution to solids for shipment.
As discussed above, 42% HFCS is used primarily in bakery goods and dairy products. An additional stage (Stage 5) is required to convert 42% HFCS to 90% HFCS, which is in turn mixed with 42% to produce a third type of HFCS, 55%. 55% HFCS is used in the soft drink industry, and is the higher value HFCS product.
Stage 5: This stage involves the selective concentration of the 42% fructose: 52% dextrose product of Stage 4 to a higher concentration fructose product (90%) and its blending with the original 42% to produce other concentrations.
Since fructose preferentially forms a complex with cations, while dextrose does not, various purification processes utilize this difference either through chromatographic fractionation using organic resins or through inorganize resins in packed bed systems. The immediate product of Stage 5 is a Very Enriched Fructose Corn Syrup (VEFCS) with a 90% fructose concentration. This VEFCS can be used in turn with the 42% HFCS to produce a product with concentrations between 42% and 90% fructose, the most common being, as stated above, 55%.
The processes required to produce HFCS from corn starch is portrayed schematically in FIG. 2. FIG. 2 restates the 5-stage process given in FIG. 1 in terms of processing stages within the HFCS-producing plant.
Saccharification corresponds to Stage 1 of the process detailed above in Section 2, in which the initial input of corn starch is converted to a dextrose feedstock. Purification and pretreatment, in which the dextrose feedstock is refined further before the isomerization to HFCS, correspond to Stage 2. The isomerization process, in multiple reactors, corresponds to Stage 3. Finally, the post-treatment processes, in which impurities-are removed (Stage 4) and the HFCS can undergo further refinement to higher HFCS concentrations, correspond to Stages 4 and 5.
Thus, the production of high-fructose corn syrup is generally accomplished by the large-scale enzymatic conversion of corn starch to fructose. The process steps entail a saccharification step which consists of enzymatic hydrolysis of corn starch to dextrins and then to glucose by the action of amylase and amyloglucosidase followed by an isomerization step which entails passing saccharified syrup over a column of immobilized glucose isomerase resulting in the conversion of glucose to fructose.
The isomerization step is one of the primary process-regulating steps, and represents a major expense in the process. See Novo Industric A/S (1985.) Novo Enzyme Information. IB No. 175d-GB. Continuous Production of Fructose Syrup with Novo's Immobilized Glucose Isomerase, Sweetzyme Type Q. 56 pp. Novo Alle, D.K-2880 Bagsvaerd, Denmark; and Novo (1987) Novo Analytical Method No. AF 230/1-GB. Novo method for Activity Determination of the Immobilized Glucose Isomerase-Sweetzyme T. 7 pp. The activity and the stability of the glucose isomerization enzyme control the productivity of the process. The activity of the enzyme is the rate of conversion of glucose to fructose under given process conditions. The stability of the enzyme is an expression of its usable life span and the rate of decay of its activity under process conditions. A third potential, as yet heretofore undemonstrated, would be a change in the equilibrium concentration of fructose obtained under process conditions.
In view of the importance of this process, a need exists for a method by which the effectiveness and efficiency of the process may be improved, particularly in terms of enzyme activity, longevity, process equilibrium and/or flow rate.

Method of producing high fructose corn syrup from glucose using noble gases


In a mobile terminal having a case defining an appearance of the terminal, and a fabrication method for the case, the mobile terminal includes a plurality of pieces formed of zirconia or ceramic and each having a preset shape, and a frame recessed into one surface of the case to receive the plurality of pieces, the frame covering edges of the plurality of pieces, wherein the plurality of pieces are aligned in a repetitive manner to define one surface of the case.

1. Field of the Invention
This specification relates to a mobile terminal having a case, and a method for fabricating a case thereof.
2. Background of the Invention
Mobile terminals are electronic devices which are portable and have at least one of voice and telephone call functions, information input and/or output functions, a data storage function and the like.
As it becomes multifunctional, the mobile terminal can be allowed to capture still images or moving images, play music or video files, play games, receive broadcast and the like, so as to be implemented as an integrated multimedia player.
Various attempts have been done for the multimedia device in aspect of hardware or software in order to implement such complicated functions.
Many users have their mobile terminals to express their own personalities, and accordingly, various designs are required for the mobile terminal. The various designs include structural change (variation, modification) and improvement of outer appearance of the mobile terminal.
The mobile terminal includes a case configuring its appearance. The case may not only simply protect the mobile terminal from external environments but also provide an aesthetic function. As an example of the structural change and improvement, a mobile terminal whose case has various patterns can be considered.

Mobile terminal and method for fabricating case thereof


A system which determines whether one of a plurality of peripheral devices on a SCSI bus is providing termination power to a bus terminator and provides termination power from a power supply associated with a host device only when none of the peripheral devices are providing termination power. The system is further configured to only provide termination power from the host device when information signals are likely to be present on the information bus. Specifically, the system only provides termination power when the host device seeks access to the information bus to thereby limit consumption of the host device's power supply.

1. Field of the Invention
The present invention generally relates to a system for providing termination power to a computer bus and, in particular, concerns a system which ascertains whether termination power is already being provided by other devices on the computer bus and, if not, provides termination power on an as needed basis.
2. Description of the Related Art
Presently, the standard bus for interconnecting computers and peripheral devices is the Small Computer System Interface (generally known as SCSI) bus which is a parallel multi-master input/output bus. A SCSI bus connected network can be viewed as a chain of devices linked together by the SCSI bus wherein the SCSI bus forms a general purpose interface between each of the devices. Generally, a SCSI bus network includes a host device and up to seven other peripheral or auxiliary devices wherein the host device can be comprised of a personal computer (PC) and the peripheral devices can include equipment such as printers, auxiliary information storage devices, CD ROM drivers, etc.
Signals that travel on the bus between devices have wave-like properties. For example, when the signals travelling along the bus come to an end or termination of the bus, these signals can be reflected back along the bus unless some system has been implemented to cancel the signals reaching the termination of the bus. Reflected signals travelling back along the bus can interfere with other signals carried on the bus possibly corrupting the data carried by the bus.
For this reason, on most SCSI busses, a termination is provided at the end of the bus which inhibits the reflection of signals on the bus. A typical prior art termination is provided by a pull-up pull-down resistor pack, known as a SCSI bus terminator, that performs the function of absorbing excess energies at the end of the bus and not allowing these energies to be reflected back, along the bus.
FIG. 1 illustrates a typical prior art SCSI bus terminator for a single data or control line of the SCSI bus. Similar bus terminators are generally provided for each of the data and control lines contained on the SCSI bus. This type of bus terminator requires 5 volts and 1 amp to operate. Another type of termination used on SCSI busses is an active terminator which provides signals to actively cancel signals on the data and control lines at the termination of the bus. One common type of active termination device is a UC 5601 small computer system interface active terminator available from Unitrode Integrated Circuits. These active terminators also require a significant amount of power, e.g., 2.9 volts. In the past, the power for either type of bus terminator has been provided by the host device, e.g., the personal computer. The standard desktop personal computer generally does not have any difficulty in providing termination power for the bus terminator as it usually receives power from a standard 120 VAC electrical outlet.
However, there are some situations where it is undesirable for the host device to be the source of termination power for a SCSI bus. Specifically, portable computers, notebook computers and palmtop computers are becoming increasingly popular and more powerful. Typically, these types of computers are battery powered. If one of these types of computers is used as a host device and is linked to peripheral devices via an information bus, such as a SCSI interface, and it is to provide the termination power, the resulting drain on the battery would significantly deplete the limited energy contained in the battery. In some circumstances, termination power requirements can use up to 45% of a battery's capacity. Hence, providing termination power from the battery can significantly reduce the battery's available power and thereby significantly reduce the use of the host device.
In some circumstances, however, one of the peripheral devices can be configured to provide the termination power. This can solve the problems associated with a battery operated host device having to provide termination power provided that the termination power provided by the host device is disabled or the host device is designed to never provide termination power. If more than one device is providing termination power to the SCSI bus terminator, the bus terminator can become unreliable and the devices providing the termination power can be damaged.
While some host devices can be configured to not provide termination power, this configuration generally requires making relatively complex adjustments to the host device, e.g., setting dip switches or modifying operating instructions. Hence, even if prior art systems can be configured so that the host device does not have to provide termination power, the system can't be readily changed in the event the host device has to provide termination power, such as when the peripheral device providing termination power fails or is removed from the bus. Further, if the host device is designed to never provide termination power, the flexibility of the host device to be used with some peripheral devices is significantly limited as many peripheral devices are not designed to provide termination power either.
Hence, there is a need for a system which can sense when a peripheral device is providing termination power to an information bus and disable the termination power provided by a host device when a peripheral device is providing the termination power. However, the system should be capable of providing termination power from the host device in the event that no peripheral device is capable of providing termination power. Further, the system should be flexible so that it can be used in conjunction with a network of devices with a minimal amount of reconfiguration of the devices being required.
In the event that the host device is required to provide termination power from a limited power source, it would be desirable to control the termination power from the host device so that the energy used to provide termination power is minimized. To this end, it would be desirable to have a system which would provide the termination power from a host device with a limited power source only when the termination power is actually needed to thereby conserve the energy in the limited power source.

System and method for selectively providing termination power to a SCSI bus terminator from a host device


Battery powered electrical equipment such as a portable personal computer operates in one of plural power saving modes to control operating speed and display brightness. The remaining capacity of the battery powering the electrical equipment is derived and one of the power saving modes is selected. The selected power saving mode is automatically displayed in close relationship with the remaining battery capacity so that an operator can readily determine the remaining operating time of the equipment.

In battery powered electrical equipment, remaining battery capacity can be detected and displayed to certify a term of energizing the equipment. There is other equipment in which an energy saving mode or usual mode can be selected to prolong the term of energizing the equipment. In this equipment, an operator has to operate some keys. Furthermore, it is necessary to operate some keys to insure a current energy saving mode. In this case, the displayed current energy saving mode has no relation to the displayed remaining battery capacity. That is why it is difficult to confirm that an appropriate energy saving mode is selected in accordance with the remaining battery capacity by the contents of displayed information. Furthermore, while executing data processing in a normal energy saving mode, the equipment sometimes goes down and important data are lost as a result of loss of the battery power.
Even if the remaining battery capacity and the selected battery energy mode are displayed simultaneously, it is difficult for an operator to select an appropriate mode for desired operating time.

Battery powered electrical equipment with power saving operation


Apparatus for launching inflatable fascines comprising a conveyor system to which uninflated fascines are attachable for delivery to a launching region and an inflator to effect inflation and launch of the fascines. The conveyor (2) comprises a number of rigid conveyor members (12), each of which constitutes a fascine support location. At each of the support locations a packaged fascine (24), comprising a deflated fascine (23) housed between a backing plate (25) and a frangible or hingeable containment member (26), is attachable. The packaged fascines (24) may also contain a reservoir of pressurized gas (32) for inflation purposes. The conveyor (2) is connected via drive wheels (9) to a motor (6) such that the support locations carrying the packaged fascines (24) are sequentially delivered to a fascine launching region (14).

The present invention relates to apparatus used for the launching of fascines and in particular to apparatus used for the launching of inflatable fascines.
Fascines are structures which are commonly used to enable vehicles and personnel to cross ditches and conventionally comprise bundles of elongate members. Recently fascines comprising bundles of plastic pipes have been employed an example of which is described in EP patent 0149314. A fascine which may be stored more compactly and which comprises a core of inflatable members surrounded by a necklace of rigid plastic pipes is described in UK patent 2242468. Fascines of the non inflatable kind are frequently used in military applications to enable tanks and other vehicles to cross ditches and when such an operation is to be performed under enemy fire there is a requirement for the deployment to be effected without exposing personnel. To this end tanks equipped with apparatus for the automatic launching of the fascines have been proposed. Due to the size of fascines required for military applications tank borne apparatus for the launching of the non inflatable type of fascine described in EP patent 0149314 is only able to carry and deploy a small number of fascines. UK patent 2242468 discloses apparatus which can carry and deploy more fascines because they have inflatable core members. Even so relatively frequent return to a safe area to re-stock with fresh fascines will be necessary which will severely inhibit the ability of a fascine deploying tank to keep up with the front line of an armoured advance.

The Secretary of State for Defence in Her Britanic Majesty's Governement of the United Kingdom of Great Britain and Northern Ireland


An oil-based drilling fluid with jojoba oil as a main component. Jojoba oil is non-toxic and biodegradable. This environmentally-friendly oil-based drilling fluid also comprises water, a viscosifier, an emulsifier, and an absence of diesel and/or mineral oil.

Technical Field
The disclosure relates to an oil-based drilling fluid comprising jojoba oil, which is substantially free from diesel, mineral, and crude oil.
Description of the Related Art
The "background" description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
When drilling an oil well, a drilling fluid has to be used to transport the debris generated by drilling to the surface. The drilling fluid must also cool and lubricate the tool, maintain the wall of the borehole, exert a sufficient counter-pressure, and prevent damage to the formation (Hossain, M. E., Al-Majed, A. A., Fundamentals of Sustainable Drilling Engineering, ISBN 978-0-470-87817-0, John Wiley & Sons, Inc. Hoboken, N.J., and Scrivener Publishing LLC, Salem, Mass., USA, pp. 786, 2015—incorporated herein by reference in its entirety). Two types of drilling fluids are mainly used: water-based and oil-based fluids. Water-based fluids are more economical and ecologically acceptable than oil-based fluids. However, the latter have clear operational advantages, in particular when drilling under high pressure and high temperature conditions such as those in extremely deep wells. High pressure and high temperature wells often have pressures exceeding 69 MPa and temperatures higher than 150° C. The oil-based fluid is inert to the components of the geological formation, especially clay, thereby minimizing damage to the drill zone, and the fluid reduces friction better than water-based fluids.
Research in this field has gradually shifted from traditional oil-based fluids that are rich in diesel oil to oil-based fluids that usually contain plant oils and are therefore less noxious to the environment. However, the plant oils are not as thermally stable as diesel oil. In temperatures beyond 150° C., the environmentally-friendly plant oil-based fluids degrade, and can damage the reservoirs and reduce productivity in wells.
Safety and environmental factors are considered when choosing an oil for the drilling fluid. Products that have been used in the past may no longer be acceptable. As more environmental laws are enacted and new safety rules applied, the choice of the oil must also be re-evaluated. To meet the challenges of a changing environment, product knowledge and product testing become essential tools for selecting suitable oils for drilling fluid systems. Beginning in the 1990s, environmentally friendly drilling fluid systems have been developed that have low toxicity, easy degradation and little effect on environment. However, these fluid systems fail to be widely applied due to high costs or unsatisfactory application effects. There are also some newly developed drilling fluid systems which have complex synthetic process, failing to achieve industrialized manufacture. It is therefore necessary to develop a new environmentally friendly drilling fluid system which is easily synthesized, economical, and can protect the environment and oil reservoirs while satisfying the needs of drilling engineering. Several research groups have explored and reported low toxicity drilling fluids.
Bailey et al. (1986) examined viscosities of drilling fluids formulated with low toxicity mineral oil and diesel oil under different temperatures and pressures (T. Bailey, P. Bern, F. McEwan, 1986, Low Toxicity Oil Muds: A Knowledge of Downhole Rheological Behavior Assists Successful Field Application, SPE Drilling Engineering, 107-114—incorporated herein by reference in its entirety).
Yassin et al. (1991) carried out tests on palm oil derivatives as the oil in oil-based drilling fluids and the toxicity effect on plant and aquatic life (A. Yassin, A. Khamis, O. A. Mohamed, 1991, Formulation of an Environmentally Safe Oil Based Drilling Fluid, SPE Asia-Pacific Conference—incorporated herein by reference in its entirety). The oils used in this case were methyl esters of crude palm oil and methyl esters of fatty acids in distilled palm oil. Physio-chemical properties of these oils, such as flash point, pour point, aniline point, were characterized at various temperatures and pressures.
Sanchez et al. (1999) formulated drilling fluids from mineral oil, which has less than 0.1% aromatics, and palm oil, which does not have aromatics (G. Sanchez, N. Leon, M. Esclapes, I. Galindo, A. Martinez, J. Bruzual, I. Siegert, 1999, Environmentally Safe Oil Based Fluids for Drilling Activities, SPE/EPA Exploration and Production Environmental Conference—incorporated herein by reference in its entirety). The toxicity and biodegradability of mineral oil and palm oil-based drilling fluids were compared to those of a diesel oil-based drilling fluid. The results indicated that both drilling fluids containing mineral oil and palm oil are non-toxic while the diesel oil-based drilling fluid showed high levels of toxicity.
Dosunmu et al. (2010) developed an oil-based drilling fluid with palm oil and ground nut oil (A. Dosunmu, J. O. Ogunrinde, 2010, Development of Environmentally Friendly Oil Based Drilling fluid Using Palm Oil and Groundnut Oil, Nigeria Annual International Conference and Exhibition—incorporated herein by reference in its entirety). The fluid not only met the environmental standards, but also improved crop growth when discharged into farm lands.
Amanullah et al. (2010) proposed waste vegetable oil as an alternative to mineral oil and diesel oil in high performance drilling fluids for high pressure high temperature wells (M. Amanullah, H. H. Mohammed, 2010, The Recycling of Waste Vegetable Oil for Biodegradable and Environment Friendly OBM Formulation, The 2nd Saudi Meeting on Oil and Natural Gas Exploration and Production Technologies, KFUPM Campus, Dhahran, Saudi Arabia—incorporated herein by reference in its entirety). Large volumes of waste vegetable oil are generated annually worldwide. The drilling fluid with waste vegetable oil is not only eco-friendly, but also economical.
Apaleke et al. (2012) formulated a drilling fluid with canola oil as the base oil for an oil-based fluid, which is environmentally friendly, sustainable, and has zero level of toxicity (A. S. Apaleke, A. A. Al-Majed, M. E. Hossain, 2012, State of the Art and Future Trend of Drilling Fluid: An Experimental Study, SPE Latin America and Caribbean Petroleum Engineering Conference—incorporated herein by reference in its entirety). The developed canola oil system was found to be stable at room temperature and simulated downhole conditions. Moreover, the canola oil-based fluid system was formulated without a wetting agent which helped in reduction of the cost of formulation.
Fadiro et al. (2012) evaluated the environmental impact of three different oil-based fluids with base oils, diesel, jatropha oil, and canola oil (A. Fadairo, O. Falode, C. Ako, A. Adeyemi, A. Ameloko, 2012, Novel Formulation of Environmentally Friendly Oil Based Drilling fluid, New Technologies in the Oil and Gas Industry, 49-80—incorporated herein by reference in its entirety). The results obtained from laboratory tests indicated that jatropha oil has a low degree of toxicity and may be an environmentally viable replacement for the conventional and toxic diesel based fluid.
In view of the foregoing, the objective of the present invention is to provide an oil-based drilling fluid that contains jojoba oil, and which is substantially free from diesel, mineral, and crude oil.

Oil-based drilling fluid employing jojoba oil

King Fahd University of Petroleum and Minerals


Bonded, coherent fibrous web substrates well adopted as cathodic elements for electrolytic cells and advantageously incorporating an electrocatalytic agent, include a web matrix which comprises a plurality of fibers, at least a portion of which comprising electrically conductive fibers, e.g., carbon fibers, said plurality of fibers being coherently bonded together with a fluorine-containing polymer, and said web substrate having a resistivity of up to about .[.0.4.]. .Iadd.4.0 .Iaddend..OMEGA..cm.

1. Field of the Invention
The present invention relates to a material which is especially adopted for the production of the cathodic element, or cathode, of an electrolysis cell, and particularly an electrolysis cell for aqueous alkali metal halide solutions. The invention also relates to a cathodic element per se, comprising said material. The invention lastly relates to processes for the production of said materials and of said cathodic elements, or cathodes, therefrom.

Electrically conductive fibrous web substrate and cathodic element comprised thereof


A disposable oil filter for an internal combustion engine, the filter having means to produce a magnetic field in an area of the filter which is not subject to the full flow of oil, so that the attracted magnetic particles are not liable to be swept away by the oil flow.

Ideally, the function of the lubrication system of an internal combustion engine is to supply clean oil cooled to the proper viscosity to the critical points in the engine, where the motion of the parts produces hydro-dynamic oil films to separate and support the various rubbing surfaces.
Since the lubricating oil flows to all parts of the engine, it is important that it does not carry abrasive or corrosive material with it. Such material may come from the combustion of the fuel, from dirt in the inducted air, or from parts of the engine itself. It is common practice to filter oil or part of the oil as it flows through the system to reduce wear.
In some engines a small fraction of the oil leaving the pump is continually bypassed through a filter and returned to the crank case. The rest of the oil is directed to the bearings.
However, since considerable time is required for all the oil to be filtered by this method, most automobile engines pump all the oil through a full flow filter placed in line between the pump and the bearings.
Ideally, such a full flow filter would filter out of the oil all the abrasive materials and particles in the oil, even the microscopic metal particles which are abraded from the moving surfaces of the engine in the normal wearing process.
However, for a filter to remove all of this material, the filter would have to be designed and be constructed of a material suitable to remove these microscopic particles, and such a filter would severely impede the flow of oil to a degree where insufficient oil would flow to the bearing, and also would require excessively high pressures to force the oil through this fine material.
Hence, presently designed filters are such that they remove all the larger abrasive particles, and their filtering element is also designed to allow the additives in the cell to circulate with the oil and not be filtered therefrom, these additives including the viscosity-index improvers, the antioxidants, the anti-wear and friction reducing additives such as the alkaline-earth phenates and the dispersants which additives have effect to ensure that foreign particles are kept in suspension in the lubricating oil and are not to form sludges and lacquers on the various component parts.
Also in this connection, various wear reducing additives such as graphite and molybdenum disulfide are added to the oils in order to assist in the lubrication of the engine.
The oil filter ideally should remove all abrasive particles, no matter how microscopic, from the oil but should also allow the desired additives in the oil to circulate and clearly remain in the oil. However, the filters are designed to allow the oil and its additives to freely circulate, and thus do not effectively remove the minute abrasive particles which circulate with the oil as a result of the normal wearing process which occurs in the engine.


The present invention includes a radiation collector configured to collect incident radiation. The radiation collector includes a radiation directing component configured to redirect the incident radiation, a buffer component configured to receive the radiation redirected by the radiation directing component, and a propagation component configured to receive the radiation from the buffer component and to propagate the radiation towards a first end of the propagation component.

The present invention relates to collectors configured to collect electromagnetic radiation and in particular, collectors configured to collect solar radiation and further relates to optical connectors for coupling radiation from a first optical component to a second optical component.
Solar energy collectors have used holographic elements to alter the direction of incident sunlight. Such example solar collectors include U.S. Pat. No. 4,863,224; U.S. Pat. No. 5,877,874, and U.S. Pat. No. 6,274,860. However, each of these systems discuss the need to alter the holographic element at various spatial regions in order to avoid unwanted decoupling of solar energy from the solar collector. Such requirements result in complex systems which are not practical.
In one exemplary embodiment of the present invention includes a radiation collector configured to collect incident radiation. The radiation collector includes a radiation directing component configured to redirect the incident radiation, a buffer component configured to receive the radiation redirected by the radiation directing component, and a propagation component configured to receive the radiation from the buffer component and to propagate the radiation by at least total internal reflection. Other embodiments of the present invention further include connectors for coupling radiation from a first optical component to a second optical component.
In another exemplary embodiment, a collector for collecting radiation incident on the collector from at least a first direction comprises a propagation component configured to transmit radiation and having a first end and at least a first refractive index; a buffer component coupled to the propagation component and configured to transmit radiation and having at least a second refractive index, the second refractive index being less than the first refractive index of the propagation component; and a radiation directing component coupled to the buffer component and configured to redirect the incident radiation from the at least first direction along at least a second direction different than the first direction within the buffer component, such that the radiation enters the propagation component and is propagated within the propagation component toward a first end of the propagation component by at least total internal reflection. In one example, the radiation is solar radiation and the buffer component is positioned relative to the propagation component and the radiation directing component, such that the radiation propagating in the propagation component is prevented from interacting with the radiation directing component.
In yet another exemplary embodiment, a collector for collecting radiation incident on the collector from at least a first direction comprises a radiation directing component configured to redirect the incident radiation; a buffer component coupled to the radiation directing component and configured to receive the radiation redirected by the radiation directing component; and a propagation component coupled to the buffer component and configured to receive the radiation from the buffer component and to propagate the radiation generally in a first direction toward a first end of the propagation component by at least total internal reflection, the radiation directing component being positioned such that the radiation incident on the collector which is received into the propagation component is incident from a direction generally not parallel with the first direction of the propagation component.
In a further exemplary embodiment, a solar collector configured to collect incident solar radiation and to be affixed to a surface of a building comprises an optical component having a top surface and a first end, the optical component configured to receive the incident solar radiation through the top surface and to collect the incident solar radiation at the first end of the optical component; and an attachment component coupled to the optical component, the attachment component configured to receive at least one fastening components to secure the attachment component to the surface of the building.
In one exemplary method, a method of collecting incident radiation comprises the steps of receiving the incident radiation from at least a first direction; redirecting the incident radiation with a radiation directing component into a propagation component; retaining the radiation in the propagation component such that the radiation is propagated generally toward a first end of the propagation component; and optically separating the radiation component from the propagation component such that the radiation propagating with the propagation component is prevented from interacting with the radiation directing component.
In another exemplary method, a method of coupling optical radiation from at least a first source of optical radiation into a first optical transport component including a first propagation component and a first buffer component, the first buffer component radially overlaying the first propagation component and the first optical transport component configured to propagate optical radiation in generally a first direction toward a first end of the first optical transport component or in generally a second direction toward a second end of the first optical transport component comprises the steps of positioning the at least first source of optical radiation adjacent an exterior radial surface of the first buffer component; and directing at least a portion of the radiation emanating from the source of optical radiation into the first buffer component of the first optical transport component such that the radiation is coupled into the first propagation component and is propagated within the first propagation component toward at least one of the first end or the second end of the first propagation component due at least to total internal reflection between the first propagation component and the second component.
In yet a further exemplary embodiment, an optical connector for transferring radiation comprises a first optical transport component including a first propagation component and a first buffer component, the first buffer component radially overlaying the first propagation component, the first optical transport component configured to propagate optical radiation in generally a first direction toward a first end of the first optical transport component; a second optical transport component including a second propagation component and a second buffer component, the second buffer component radially overlaying the second propagation component, the second optical transport component configured to propagate optical radiation in generally a second direction toward a second end of the second optical transport component, the second optical transport component being positioned such that the second direction is not parallel to the first direction; and a radiation directing component located proximate to the first end of the first optical transport component and proximate to an exterior surface of the buffer component of the second optical transport component, the radiation directing component configured to redirect the optical radiation propagating generally in the first direction through the exterior surface of the second optical transport into the second propagation component such that the optical radiation is propagated within second optical transport component generally along the second direction of the second optical transport component.
Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.

Electromagnetic radiation collector and transport system


A weld current switch includes a channel-shaped core, a shunt, and a magnetic reed switch. The magnetic reed switch and shunt are placed across the core poles. An electrical conductor carrying high current passes through the core. Upon deenergization of the electrical current, a residual magnetism remains in the core. The residual magnetism is normally high enough to prevent the magnetic reed switch from opening. However, the shunt directs sufficient magnetic flux from the switch such that the switch senses a much lower level of magnetic flux than if the shunt were not present. As a result, the switch opens, even with the high residual flux in the core. The increased reliability of the switch upon decreasing current at electrical conductor deenergization enables the weld current switch to use a higher sensitivity switch than was formerly possible. The higher sensitivity switch reduces the level of magnetic flux at which the reed switch will close on increasing current upon energization of the electrical conductor.

1. Field of the Invention
This invention pertains to electrical controls, and more particularly to apparatus that utilizes magnetic fields to control electrical circuits.
2. Description of the Prior Art
It has long been known that a magnetic field exists around an electrical conductor, and that the strength of the magnetic field is proportional to the amount of current in the conductor. A portion of the magnetic flux can be captured in a magnetic core that surrounds the conductor. The core can be continuous, or it can be discontinuous such that an air gap exists between two ends of the core.
The magnetic flux surrounding a current carrying conductor is frequently used to control electrical circuits. For that purpose, a magnetic reed switch or other electrical device may be placed in the air gap of a discontinuous core. When the current in the conductor, and thus the amount of magnetic flux in the core and air gap, reaches a predetermined value, the flux acts to magnetize the switch and cause it to close. The switch may be incorporated into any of a great number of circuits for controlling components based on the state of the switch.
An exemplary application of a magnetic field operated switch is weld current relay Model No. 007 036 manufactured by Miller Electric Manufacturing Company of Appleton, Wis. FIGS. 1 and 2 show the relevant components of this prior weld current relay, which is indicated by reference numeral 1. The weld current relay 1 is made with a core 3 of magnetically permeable material, such as soft iron. The core 3 has spaced apart and overlapping ends 5. The spaced apart ends 5 form an air gap between them. The ends 5 are tapered, as shown at reference numerals 7. A tube 9 of non-magnetic material, such as copper, is secured to the core in the air gap between the two core ends. Inside the tube 9 is a magnetic reed switch 11. The magnetic reed switch 11 is composed of a glass bulb 13 and a pair of contacts 15 and 17 embedded in the wall of the glass bulb, as is known in the art. The contacts 15 and 17 are connected to two wires 23 and 25 that lead to a control device typically represented by block 27. The control device 27, in turn, controls various components, typically represented by block 29, of a welding system.
An electrical cable 31 passes through the core 3. When there is no current in the conductor 31, there is no magnetic flux in the core or in the magnetic reed switch 11, and the switch contacts 15 and 17 are open. When current passes through the conductor 31, magnetic flux is induced within the core 3. The flux passes between the core ends or poles 5, where it is concentrated by the tapers 7. When the flux reaches a predetermined level, it causes the contacts 15 and 17 to close. The closed contacts activate an appropriate portion of the control device 27 to control the components 29. For example, the control 27 may control such welding system components as valves that release protective gases around a welding arc and mechanisms that feed welding wires, such that gas flows or weld wire is fed in response to the existence of weld current.
Equally important as the closing of the contacts 15 and 17 of the weld current relay 1 upon start up of current in the conductor 31 is the opening of the contacts upon shut off of the current. Opening of the magnetic reed switch 11 can control, for example, closure of valves that direct protective gases around a welding arc and cessation of feeding of welding wires. Because of the hysteresis of the magnetic material of the core 3, the level of the magnetic flux that will allow the contacts 15 and 17 to open on current shut off is always less than the level of the magnetic flux that will close the contacts upon current startup, as is shown in FIG. 3a. In FIG. 3a, point Ca represents the magnetic flux required to close a typical magnetic reed switch upon start up of current in a conductor, and point Oa represents the level of the flux at which the switch will reopen upon shut-off of current in the conductor.
The prior weld current relay 1 was designed to detect magnetic flux point Ca corresponding to current in the conductor 31 upon welding start up of between about 50 and 70 amps and to operate with a maximum current of approximately 500 amps. Upon shut off of the current, the hysteresis of the magnetically permeable core 3 causes the contacts 15 and 17 of the magnetic reed switch 11 to reopen at point Oa, which was at an acceptably low level of flux. Any residual magnetism in the core was not enough to prevent the magnetic reed switch contacts from properly opening when the current was zero amps.
The prior weld current relay 1 works very well, and a great number of them have been in service for several years. However, recent advances in welding technology have pointed out some limitations to the prior weld current relay. For example, the development of welding robots has led to the requirement for detecting an initial current that is substantially less than the formerly acceptable level of approximately 50 to 70 amps. That requirement is quite difficult to meet, as can be explained with reference to FIG. 4. FIG. 4 shows pertinent portions of a representative weld current relay 32 having a core 33 with first and second poles 35 and 37, respectively. A typical magnetic reed switch 39 is shown in the air gap 41 between the core poles 35 and 37. The switch has contacts 43 and 45, which are open in the absence of a sufficiently strong magnetic flux within the air gap 41. The contacts 43 and 45 are enclosed within a glass bulb 47. Contact 43 passes through the bulb 47 in the form of a magnetic wire 49 that is bent at 180 degrees such that the end 50 of the wire is proximate the bulb. Contact 45 passes through the bulb in the form of a straight wire 51.
In order for magnetic flux to close the contacts 43 and 45 of the magnetic reed switch 39, the flux must be strong enough to pass through three air gaps: the air gap 53 between the core first pole 35 and the wire 49; the air gap 55 between the two contacts 43 and 45; and the air qap 57 between the wire 51 and the core second pole 37. As mentioned, modern requirements dictate that the maximum detect point pull-in of a magnetic reed switch on increasing current in a conductor be as low as possible. For reasons to be explained shortly, it is not possible for the prior weld current relay 1 to employ a more sensitive switch in order to obtain a suitably low maximum detect point.
Another aspect of present welding practice is the use of high welding currents of 1,000 amps and more. After such a high current is turned off, the high levels of residual magnetism in the core 3 of the weld current relay 1 (FIGS. 1 and 2) may be great enough to keep the magnetic reed switch contacts 43 and 45 closed. That situation is illustrated in FIG. 3b. FIG. 3b shows that the opening point Ob of the switch contacts on decreasing current is not reached when the current falls to zero; it actually takes a negative current to decrease the residual flux sufficiently to open the switch. Consequently, the weld current relay occasionally misdetects the residual magnetism around a deenergized electrical conductor 31 following shut-off of high welding current as being the much lower level of magnetism associated with the initial welding current that provides the maximum detect point to close the switch on increasing current. As a result, the various components 29 of the welding equipment that are controlled by the welding current may continue to operate as though welding is occurring, even though in actuality welding has ceased.
The use of a higher sensitivity magnetic reed switch to close at a low level of increasing current would aggravate the problem of the switch remaining closed upon current shutdown. In other words, a higher sensitivity switch would sense a suitable maximum detect point pull-in on increasing current, but that switch would rarely, if ever, sense a suitable minimum un-detect point for drop out on decreasing current.
Another problem with prior weld current relays concerns the configuration of the magnetic reed switch wires, such as wires 49 and 51 of the typical switch 39 of FIG. 4, relative to the core ends 35 and 37. Looking at FIG. 5, a weld current relay 32' is shown in which an alternate way is used to bend the wires 49' and 51' of the magnetic reed switch 39'. The glass bulb 47' is rotated about axis 64' relative to the glass bulb 47 of the weld current relay 32 of FIG. 4, and the wire 49' of the switch 39' is therefore bent in a different configuration. The result is that the weld current relay 32' has different operating characteristics than the weld current relay 32, because the lines of magnetic flux 66 must follow different air gaps and paths between the core ends 35' and 37' compared with the core ends 35 and 37 of the weld current relay 32. This leads to inconsistent reed switch operation from one weld current relay to another.
To further aggravate the inconsistent operation of prior weld current relays, the angular displacement of the magnetic reed switch in the supporting tube 9 (FIG. 1) about its longitudinal axis, such as axis 64 of switch 32 and axis 64' of switch 32', is important. Thus, switch angular displacement introduces another variable into the performance characteristics of the weld current relay.
The wires of the magnetic reed switches of prior weld sensor relays are bent at random, and the switches are installed with random angular orientation about their longitudinal centerlines. Consequently, the performance of the prior weld sensor relays are quite inconsistent. Such inconsistent operations were rarely troublesome with prior welding equipment, but they are intolerable with modern welding robots and similar high technology equipment.


An integrated circuit including an array of flash EEPROM memory cells wherein overerase correction is provided after application of each erase pulse.

1. Field of the Invention
The present invention relates to a integrated circuit memory including an array of flash EEPROM memory cells and circuitry to provide for overerase correction for the flash EEPROM cells.
2. Description of the Related Art
FIG. 1 shows a typical configuration for an integrated circuit including a flash EEPROM memory array 100 and circuitry enabling programming, erasing, reading, and overerase correction for memory cells in the array 100. The flash EEPROM array 100 is composed of individual cells, such as 102. Each cell has a drain connected to a bitline, such as 104, each bitline being connected to a bitline pull up circuit 106 and column decoder 108. Sources of the array cells are connected to Vss, while their gates are each connected by a wordline to a row decoder 110.
The row decoder 110 receives voltage signals from a power supply 112 and distributes the particular voltage signals to the wordlines as controlled by a row address received from a processor or state machine 114. Likewise, the bitline pull up circuit 106 receives voltage signals from the power supply 112 and distributes the particular voltage signals to the bitlines as controlled by a signal from the processor 114. Voltages provided by the power supply 112 are provided as controlled by signals received from processor 114.
The column decoder 108 provides signals from particular bitlines to sense amplifiers or comparators 116 as controlled by a column address signal received from processor 114. The sense amplifiers 116 further receive a signal from reference cells of reference array 118. An example of circuitry for reference array 118, as well as operation of such circuitry is provided in U.S. patent application Ser. No. 08/160,582 entitled "Programmed Reference", and U.S. Pat. No. 5,335,198 entitled "Flash EEPROM Array With High Endurance", both of which are incorporated herein by reference. With signals from the column decoder 108 and reference array 118, the sense amplifiers 116 then each provide a signal indicating a state of a bitline relative to a reference cell line to which it is connected through data latches or buffers 120 to processor 114.
To program a cell in the flash memory array 100, high gate-to-drain voltage pulses are provided to the cell from power supply 112 while a source of the cell is grounded. For instance, during programming typically multiple gate voltage pulses of 10 V are each applied for approximately two to three microseconds to a cell, while a drain voltage of the cell is set to 5.5 V and its source is grounded. The large gate-to-drain voltage pulses enable electrons flowing from the source to drain to overcome an energy barrier to produce "hot electrons" which are accelerated across a thin dielectric layer enabling the electrons to be driven onto a floating gate of the cell. This programming procedure, termed "hot electron injection" results in an increase of a threshold voltage for the cell, the threshold being the gate-to-source voltage required for the cell to conduct.
To erase a cell in the flash memory array 100, a procedure known as Fowler-Nordheim tunneling is utilized wherein relatively high negative gate-to-source voltage pulses are applied for a few tenths of a second each. For instance, during erase multiple gate voltage pulses of -10 V are applied to a cell, while a drain of the cell is set to 5.5 V and its source is floating. The large negative gate-to-source voltage pulses enable electrons to tunnel from the floating gate of a cell reducing its threshold.
To represent a data bit, the floating gate of a cell is programmed or erased as described above. In a programmed state, the threshold voltage of a cell is typically set at greater than 6.5 volts, while the threshold voltage of a cell in an erased state is typically limited below 3.0 volts. To read a cell, a control gate voltage between the 3.0 and 6.5 volt range, typically 5 V, is applied. The 5 V read pulse is applied to the gate of an array cell as well as a cell in reference array 118 having a threshold near 5 V. In a programmed state with an array cell in array 100 having a threshold above 6.5 V, current provided by the reference cell with a threshold of 5 V will be greater indicating a programmed cell exists. In an erased state with a threshold of a cell in array 100 below 3.0 V, current provided by the array cell will be greater than the reference cell with a threshold of 5 V indicating an erased cell. To verify programming or erase, a read voltage is similarly applied to both a cell in the array and to cells in the reference array 118. For programming, a reference cell having a threshold of 6.5 V is used for a comparison, while for erase, a reference cell having a threshold of 3.0 V is used for comparison.
In a flash memory array, all cells are typically erased simultaneously. Erasing of the memory cells is typically done by repeated applications of the short erase pulses, described above, applied to each of the cells in an array, such as flash memory array 100. After each erase pulse, erase verify is performed cell by cell to determine if each cell in the array has a threshold above a limit, such as 3.0 V, or if a cell is "undererased". If an undererased cell is detected, an additional erase pulse is applied to the entire array. With such an erase procedure, a cell which is not undererased will also be repeatedly erased, and its floating gate may eventually acquire a threshold below zero volts. A cell with a threshold erased below zero volts is referred to as being "overerased".
An overerase condition is undesirable because the programming characteristics of an overerased cell more rapidly become deteriorated, reducing the number of times the cell can be reprogrammed which is referred to as the cells "endurance". Overerased cells are also undesirable because they create bitline leakage current during program or read procedures. For instance, during program or read, only one wordline carries a positive voltage, while the remaining wordlines are typically grounded. With wordlines grounded, or at 0 V, a cell with a threshold voltage below 0 V will conduct a bitline leakage current. With bitline leakage current, power supplies providing power to a bitline during programming may become overloaded. Similarly, with bitline leakage current during read, read errors may occur.
To prevent overerase, manufacturers of integrated circuits containing flash memory cells typically provide an overerase correction mechanism. FIG. 2 is a flow chart illustrating a prior art erase and overerase correction procedure. In the procedure, erase is performed first, and then overerase correction is provided. The procedure of FIG. 2 will be described in more detail below.
First, for the erase procedure, in steps 202 and 204, the row address and column address provided by processor 114 are set to an initial address. Next, in step 206, an erase verify pulse is provided to a cell as selected by the row and column addresses. Outputs from sense amplifiers 116 are then utilized by processor 114 to determine if the cell referenced by the row and column addresses is undererased. If the cell is undererased an erase pulse is applied in step 208 to the entire array and the erase verify step 206 is repeated.
If the cell referred to by the row and column addresses is not undererased in step 206, the column address is incremented in step 210. Next, in step 212, if the last column address has not been exceeded, control returns to step 206. Otherwise, in step 214 the row address is incremented, and if the last row address has not been exceeded in step 216, control is returned to step 206. If the last row has been exceeded, the column address is reset in step 218 to begin the overerase correction procedure.
Next, in the overerase correction procedure, in step 220 power supply 112 is controlled to provide an overerase verify pulse to bitlines of the cells referred by the column address, while wordlines remain grounded. Outputs from sense amplifiers 116 are then provided to the processor 114 to determine if the bitline referenced by the column address is providing a leakage current. If the bitline is providing a leakage current, overerased cells exist, so in step 222 power supply 112 is controlled to provide an overerase correction pulse to all the cells connected to the bitline referred to by the column address and step 220 is repeated.
The overerase correction pulse applied in step 222 is a relatively high voltage applied to the drain of a cell, such as 6 V, while its gate and source are typically grounded. U.S. patent application Ser. No. 08/269,530 entitled "Multistepped Threshold Convergence For A Flash Memory Array", and U.S. Pat. No. 5,359,558 entitled "Flash EEPROM Array With Improved High Endurance", both incorporated herein by reference, disclose further details regarding application of overerase correction pulses.
If no bitline leakage current is identified in step 220, the column address is incremented in step 224. Next, in step 226, if the last column address has not been exceeded, control is returned to step 220. Otherwise, the overerase correction procedure is complete.
Although the overerase correction procedure illustrated in FIG. 2 eliminates overerased cells, because overerased cells may have been present during the erase procedure, the endurance of cells in the array will be reduced.
Further, because overerased cells may have been present during erase verify in step 206, undererased, or programmed cells may still be present after the erase procedure is complete. In explanation, during erase, one cell in an array may erase on the order of one 100 times faster than other cells. If the cell verified in step 206 is erased very slowly, while a cell in the same column is erased rapidly by continual applications of the erase pulse of step 208, the cell in the same column which erases faster may become overerased before the cell addressed in step 206 is verified as properly erased. Since during verify in step 206, the remaining cells on the column other than the cell addressed have grounded wordlines, the overerased cell will conduct a bitline leakage current. With such bitline leakage current adding to the current conducted by the addressed cell, a sense amplifier comparing the current of the addressed cell to current of a reference cell in reference array 118 will prematurely indicate for step 206 that the addressed cell has been properly erased. Thus, after completion of erase, cells may remain undererased.

Overerase correction for flash memory which limits overerase and prevents erase verify errors


Cyclofluoralkylated fullerene compounds are prepared by reacting the fullerenes with a fluoroalkene as exemplified by tetrafluoroethylene or perfluoromethyl vinyl ether under thermolysis conditions as exemplified by temperatures of 200.degree. C., pressure and a halocarbon solvent, the products being useful as lubricants or additive thereto as well as in cooling systems, adhesives and polymers.

This invention relates to reactions of fluoroalkenes with fullerenes, and the cyclofluoralkylated products derived from these reactions.
Recent success in synthesizing macroscopic quantities of carbon clusters such as C.sub.60 and C.sub.70 (known as fullerenes), by W. Kratschmer et al., Nature, 347-354 (1990), has opened the door to the study of this new class of organic compounds. Kratschmer et al. describe the fullerene molecule C.sub.60 (also known as buckminsterfullerene) as a centrosymmetric truncated icosahedron. Pure solid buckminsterfullerene consists of somewhat disordered face centered cubic or hexagonal close packing of the centrosymmetric molecules. Isolation and characterization of higher fullerenes, specifically C.sub.76, C.sub.84, C.sub.90, and C.sub.94, have been disclosed by Francois Diederich et al., Science, Vol. 252, pages 548-551 (1991). Mixtures of giant fullerene molecules, e.g., C.sub.540, have been discussed by C. Smart et al., Chem. Phys. Lett., Vol. 188, No. 3,4, pages 171-176 (Jan. 10, 1992).
Fluorinated alkenes are known to undergo thermal cycloaddition with themselves and other alkenes to form fluorocyclobutane rings (Hudlicky, M., "Chemistry of Organic Fluorine Compounds, 2nd ed.", Ellis Horwood Ltd., pp. 450-463, 1976). Buckminsterfullerene (C.sub.60) has been proposed to undergo photochemical cycloaddition with itself in the solid state (Rao, A. M.; Zhou, Ping; Wang, Kai An; Hager, G. T.; Holden, J. M.; Wang, Ying; Lee, W. T.; Bi, Xian Xin; Eklund, P. C.; et al., Science, 1993, vol. 259. pp 955-7). Benzyne (generated as an intermediate in situ) is reported to add to C.sub.60 (Tsuda, M.; Ishida, T.; Nogami, T.; Kurono, S.; Ohashi, M., Chem. Lett., 1992, No. 12, pp 2333-2334; Hoke, II, S. H.; Molstad, J.; Dilettato, D.; Jay, M. J.; Carlson, D.; Kahr, B.; Cooks, R. G., J. Org. Chem., 1992, vol. 57, pp 5069-5071). Quadricyclane is reported to thermally add to C.sub.60 (Prato, M., et al., J. Org. Chem., 1993, vol. 58, pp 3613-3615). There are no known examples of the thermal 2+2 cycloaddition of an alkene to C.sub.60 or other fullerene in the literature. Earlier filed, commonly assigned U.S. Ser. No. 08/021,395, now U.S. Pat. No. 0.5,354,926, discloses fluoroalkylated fullerene compounds.
An object of this invention is to provide a mixture comprising cyclofluoroalkylated fullerene compounds by reaction of fullerenes with fluoroalkenes.


The present invention relates, in general, to tristetraprolin (TTP) and, in particular, to methods of modulating levels of tumor necrosis factor .alpha. (TNF.alpha.) using TTP or nucleic acid sequences encoding same. The invention further relates to methods of screening for compounds for their ability to inhibit TNF.alpha. biosynthesis.

Tumor necrosis factor alpha (TNF.alpha.) is a potent cytokine that is released from many cell types, particularly, macrophages and monocytes. TNF.alpha. also exists in a cell-membrane bound, higher molecular weight form on cells, and this form also appears to mediate a variety of biological effects. TNF.alpha. is thought to have few roles in normal development and physiology; however, it exerts harmful and destructive effects on many tissues in many disease states (Tracey et al, Ann. Rev. Med. 45:491 (1994)). Disease states in which TNF.alpha. has been shown to exert a major pathogenetic role include septic shock syndrome, cancer cachexia, rheumatoid arthritis, etc. Many investigators and pharmaceutical companies are actively investigating agents and potential drugs that can block TNF.alpha. effects, either by blocking its synthesis or interfering with its binding to its surface receptors.
One example of this approach is the use of monoclonal antibodies to TNF.alpha.. These have been used in animal models of human disease, and in human conditions such as rheumatoid arthritis (Arend et al, Arthritis and Rheumatism 38:151 (1995)). There is no question that these antibodies temporarily relieve some of the signs and symptoms of this disease in man. However, their potential widespread use is compromised by many factors, especially the fact that they seem to be only temporarily (ie, a few months) effective. Other drawbacks include expense, the need for parenteral administration, the likelihood that anti-idotype antibodies will develop, etc.
The present invention relates to a novel approach to the treatment of diseases the effects of which are mediated, at least in part, through TNF.alpha.. This approach involves the protein tristetraprolin (TTP) and nucleic acid sequences encoding same.
TTP (Lai et al, J. Biol. Chem. 265:16556 (1990)), also known as Nup475 (DuBois et al, J. Biol. Chem. 265:19185 (1990)) and TIS11 (Varnum et al, Oncogene 4:119 (1989); Varnum et al, Mol. Cell. Biol. 11:1754 (1991)), is a widely distributed 33.6 kDa phosphoprotein encoded by the immediate-early response gene, Zfp-36 (Taylor et al, Nucl. Acids Res. 19:3454 (1991)). This gene has been mapped to chromosome 7 in the mouse, and the equivalent human gene, ZFP36, has been mapped to chromosome 19q 13.1 (Taylor et al, Nucl. Acids Res. 19:3454 (1991)). TTP is the prototype of a group of proteins containing two or more highly conserved putative zinc fingers of the CCCH class (Varnum et al, Mol. Cell. Biol. 11:1754 (1991); Taylor et al, Nucleic Acids Res. 19:3454 (1991); Gomperts et al, Oncogene 5:1081 (1990); Ma et al, Oncogene 9:3329 (1994)). In addition, the protein has been shown to bind Zn.sup.++ and has been localized to the cell nucleus in mouse fibroblasts (DuBois et al, J. Biol. Chem. 265:19185 (1990)), suggesting that it may be a transcription factor. Serum or other mitogen stimulation of quiescent fibroblasts causes rapid serine phosphorylation and nuclear to cytosolic translocation of TTP (Taylor et al, J. Biol. Chem. 270:13341 (1995); Taylor et al, Mol. Endocrinol. 10:140 (1996)), both of which are likely to modulate its function in cells.
In the adult mouse, TTP mRNA is highly expressed in lung, intestine, lymph node, spleen, and thymus, with lower expression in adipose tissue, kidney, and liver, and negligible expression in skeletal muscle and brain (Lai et al, J. Biol. Chem. 265:16556 (1990); DuBois et al, J. Biol. Chem. 265:19185 (1990)). In the thymus, TTP mRNA is highly expressed in both cortical and medullary thymocytes, while in the spleen, it is highly expressed in B and T lymphocytes within the white pulp, and is expressed at somewhat lower levels in the myeloid cells of the red pulp and endothelial cells of the high endothelial venules. In addition, TTP is constitutively expressed in several types of blood cells, particularly neutrophils, macrophages and B and T lymphocytes. The function of TTP in normal vertebrate physiology, however, was heretofore unknown.

Method of screening a compound for its ability to enhance the ability of tristetraprolin to inhibit tumor necrosis factor


A mail wrapping system apparatus for preparing for mailing postal items includes receiving trays for respectively receiving postal items from companies and an extraction device for extracting from the postal items a multiplicity of same address groups of the postal items, each of the same address groups consisting of ones of the postal items having coinciding ones of destination addresses. A wrapping unit respectively individually assembles each of the same address groups into a bundle and successively wraps each of the same address groups assembled using a wrapping component with a corresponding one of the destination addresses respectively displayed on each of the wrapped same address groups to provide for mailing the wrapped same address groups. A weight sorter then sorts the wrapped same address groups into weight divisions set forth by a fee schedule of a specified delivery agency and the wrapped same address groups are sent with appropriate postage.

The present invention relates to a method and a system unit of mail wrapping, more specifically, to a method of mail wrapping and a mail wrapping system unit used to execute the method for grouping a multiplicity of address-indicated postal items, as issued and collected from a plurality of companies of various industries, at a facility in accordance with a coincidence of the destination addresses respectively expressed on said address-indicated postal items. And the present invention is designed to be used when the companies of the various industries have the address-indicated postal items (including enveloped letters and postcards intended to be delivered via a specified delivery agency and addressee-specific correspondences on which the addresses and names of the addressees are indicated in advance such as bills and account statements) respectively and at the same time the companies want to send the address-indicated postal items all together to the same addressees of households or enterprises at one time.
When a key telephone company, cellular phone companies, public corporations such as electric power companies or gas supply companies (including waterworks bureau), banking organs, credit card companies, mail-order houses that operate product sales by a direct mail method (referred to as "direct mail companies" hereinafter), government offices, and any companies of various types of industries (government offices are referred to as a part of companies in various types of industries, hereinafter) send any type of correspondence to their respective customers (including enterprises), they usually deposit such postal items in post offices individually and independently.
FIG. 6 shows the types of postal items delivered to some household. As shown in the figure, it clearly indicates that a lot of postal items are delivered to the household scattered at random over the weekdays in a given month. It is also obvious that there are many postal items, each of which carries a specific document (an exceptional correspondence on which the address and name are expressed in advance), that are issued periodically and delivered such as bills and account statements prepared by the respective companies. (For example, the key telephone company issues telephone bills once every five days, though depending on the customers' districts, and the credit card company issues account statements on specified days of the month.)
As in the typical case of the key telephone company which sends bills to the respective users of its telephone services, most companies which send postal items to their customers utilize postage discount systems available to them such as basic discount rates or special discount rates for special local mail services in order to minimize their mailing costs. The average annual postage cost of these companies in connection with postal items sent to their respective customers stands at several billion yen and in an extreme case, a company of some industry spends more than 100 billion yen a year on postage.
The circumstances do not in any way inconvenience the customers, since no customers are obliged to pay for the postage of such postal items. However, if the postal charges shouldered by such companies are increased sharply due to a revision of the Postal Law, the companies will have no alternative but to pass along the increased cost to their service charges. As a solution to this problem in the future, some companies are studying plans to send a large percentage of their postal items through private carriers which recently feature much lower service charges than the postal services.
In the conventional delivery method of postal items, a lot of postal items of similar types, such as bills and account statements, are delivered separately at random on different days of any given month, which is bothersome to some customers who believe it convenient to receive bills and account statements on a single fixed day every month and settle each payment at a bank or the like at one time.
Also post offices are under the pressure of dramatically increased indoor handling work resulting from a huge volume of mail deposited each time by different companies in different industries. With the yearly increasing number of postal items handled at post offices, it is likely that efficient transportation and delivery of these postal items will be seriously affected in the future.
Such problems as those mentioned above may be solved easily if the different companies of different industries cooperate in collecting, whether periodically or not, the address-indicated postal items issued by the companies all together at one time, sorting such postal items by forming groups of postal items having the same destination addresses, and further depositing the postal items in a specified delivery agency such as a post office or a private carrier. However, no such intensive operation systems have been initiated as yet.


A pharmaceutical composition useful for treating ocular conditions, such as glaucoma. In particular, the pharmaceutical composition is a sustained release oral dosage composition for relieving intraocular pressure comprising methazolamide and a high molecular weight binder, wherein the composition provides sustained rate of methazolamide release in an in vitro drug release profile. A filler and a lubricant may also be included.

Ocular conditions characterized by intraocular pressure, such as chronic open-angle glaucoma or secondary glaucoma, have been successfully treated by administration of methazolamide, and analogs and derivatives thereof. Methazolamide is a carbonic anhydrase inhibitor that slows the formation of excess fluids behind the cornea, by inhibiting a chemical reaction at the ciliary body.
Many prior art methazolamide compositions are administerable topically, directly to the eye. Such administration can be disadvantageous to individuals who prefer oral medications. Moreover, in topical applications, the concentration of methazolamide available to the affected tissue is difficult to regulate and maintain. The frequent necessity for re-application of topical methazolamide can be inconvenient and result in inconsistent efficacy.
Additionally, some prior art methazolamide compositions provide an oral dosage of methazolamide, but these compositions do not provide a consistent dosage of methazolamide over an extended period of time. Methazolamide is a water-insoluble, hydrophilic drug. Sustained release formulations of water-insoluble hydrophobic drugs tend to yield inconsistent drug release profiles which make it difficult to control in vivo absorption of these types of drugs in the intestines.
Various controlled release pharmaceutical formulations have been proposed in the prior art, however, none have proven economical for manufacture and satisfactory in drug release profiles. Also, some of these formulations include additional compounds, such as anionic surfactants, which are undesired. Prior art formulations of sustained release methazolamide tablets have only been achieved for dosages of methazolamide in the range of 25 to 50 mg per tablet. These prior art formulations of extended release tablets have used spherical granules of methazolamide, different types of binders, or additional compounds, but none have produced a consistent drug release profile for methazolamide having methazolamide dosages of 75 mg or more per tablet.
Prior art formulations of sustained release methazolamide tablets have used lower dosages of methazolamide, from 25 to 50 mg per tablet, in the form of spherical granules which are then tableted. While tablets comprising spherical granules are effective at these lower dosage amounts, it has been difficult to achieve or control the release of the drug in higher dosage tablets having these spherical granules. Thus, there are currently no available oral methazolamide compositions containing higher dosages, i.e. at least 75 mg, in a sustained release per diem formula. Due to the low dosages in the existing prior art formulations, the tablets must be taken several times a day, which may be problematic should the individual forget to take the oral dosage at the prescribed time. Therefore, there exists a need for a sustained release methazolamide composition that contains a higher dosage of methazolamide such that only one tablet per day is required to provide relief from intraocular pressure.
A sustained release oral dosage formula is therefore desirable to provide a therapeutic concentration of methazolamide over an extended period of time without the use of unnecessary compounds. The formula would be preferably chosen such that an individual only requires a single dosage per diem. This dosage would be preferably provided in an orally administerable tablet.

Methazolamide composition and method of use