Showing papers on "Energy source published in 1993"

Systems for identifying catheters and monitoring their use

Abstract: A catheter carries a functional component, like an ablating electrode, having a predetermined operating characteristic. The catheter also electronically retains an identification code that uniquely identifies the predetermined operating characteristic. The catheter is capable of transmitting the identification code to an external reader in response to a predetermined prompt. An associated apparatus, like an ablating energy source, reads the identification code and compares it to predetermined operating criteria. The apparatus will not permit interaction with the functional catheter component, if the identification code indicates that the functional characteristics of the catheter are not suited for the intended interaction. The catheter can also store usage information, to prevent reuse.

Culture of pig embryos

Abstract: Pig embryos can be cultured using a number of different strategies including complex approaches like culture in vivo in a surrogate oviduct (rabbit, sheep, mouse), culture in mouse oviducts in organ culture, and co-culture of embryos with cells in addition to simple approaches like culture in defined media or salt solutions. Addition of serum to medium has been of particular importance where blastocyst development and hatching are required. Pig conceptuses (day 10-15), embryonic discs or cell lines derived from conceptuses can be cultured in complex media like Eagle's minimal essential medium or Dulbecco's modified Eagle's medium with serum, although embryonic discs can be cultured in the absence of serum. In contrast, early stage pig embryos (one-cell to blastocyst) are best cultured in simpler media such as those used for mouse embryos. The media that have been used are all relatively similar in composition. They contain salts and one or more energy sources such as glucose, lactate, or pyruvate with BSA as a macromolecular component. Early attempts to culture pig embryos were not very successful, but some embryos did develop to the blastocyst stage. More recent reports indicate a much higher rate of development with relatively little or no change in media composition. Some workers have reported improved development in medium lacking glucose, which is consistent with findings with laboratory animals such as hamsters. Glutamine can serve as the sole exogenous energy source in medium lacking glucose, lactate and pyruvate. Addition of taurine and hypotaurine to culture medium enhances development of pig embryos in vitro. We suggest, where possible, adoption of a standard medium that could be used by different laboratories and, perhaps, with different species. Use of one medium for different species would simplify experimental protocols, enhance studies of comparative embryonic physiology and metabolism, and expedite transfer of information obtained in different species.

Renewable energy : sources for fuels and electricity

Abstract: This book assesses the technical and economic prospects for making fuels and electricity from renewable energy sources. Twenty-three chapters discuss the following renewable technologies: hydropower; wind energy; solar thermal electric technology; photovoltaic technology (6 chapters); ocean energy systems; geothermal energy; biomass conversion technology (8 chapters); solar hydrogen; and utility strategies for using renewables. All chapters have been processed for inclusion on the data base.

Physiological Ecology of Methanogens

Abstract: Biological methanogenesis plays a major role in the carbon cycle on Earth. Methanogenesis is the terminal step in carbon flow in many anaerobic habitats, including marine and freshwater sediments, marshes and swamps, flooded soils, bogs, geothermal habitats, and animal gastrointestinal tracts. CH4 escaping from anaerobic habitats can serve as a carbon and energy source for aerobic methanotrophic bacteria, and can escape to the atmosphere, where it is a major participant in atmospheric chemical reactions and is an important greenhouse gas.

Catalytic Materials for High-Temperature Combustion

Abstract: Catalytic combustion, as an alternative to conventional thermal combustion, has received considerable attention during the past decade. Research efforts have been promoted by the need to meet governmental demands concerning pollution and the wish to use energy sources more efficiently. The two main advantages offered by catalytic combustors over flame combustors apply to these goals: Catalytic combustion can be carried out over a wide range of fuel concentrations in air and at low temperatures. These low temperatures result in attaining NO, emission levels substantially lower than possible with conventional combustors.

Hyperthermophilic archaea are thriving in deep North Sea and Alaskan oil reservoirs

Abstract: HOT springs and hydrothermal vents harbour hyperthermophilic archaea and bacteria with the highest growth temperatures known1–6. Here we report the discovery of high concentrations of hyperthermophiles in the production fluids from four oil reservoirs about 3,000 metres below the bed of the North Sea and below the permafrost surface of the North Slope of Alaska. Enrichment cultures of sulphidogens grew at 85 °C and 102 °C, which are similar to in situ reservoir temperatures7,8. Some species were identical to those from submarine hot vents and may have entered the reservoirs in injected sea water. Several enrichments grew anaerobically in sterilized artificial sea water with crude oil as the single carbon and energy source. These hyperthermophiles may be part of novel high-temperature communities and could be responsible for in situ bioconversions of crude oil fractions at temperatures previously considered too extreme for biochemical reactions4,7,9,10.

Bipolar electrosurgical forceps

Abstract: A hand operable bipolar forceps instrument comprising two interfacing pivotal blade member's which are each an electrode individually pivotable in relation to each other. Pivotal movement of the blades is effectuated by two respective electrically-conductive rigid rods, each coupled to a respective blade member, extending through an elongated tubular member having disposed at its proximal end a scissors type handle whose hand operation causes the blade members to pivot in relation to each other. The rods are connectable proximally to an energy source to thereby electrically activate the blade members.

Trace and Minor Elements in Coal

Abstract: Coal will be a major energy source in the United States and in many other countries well into the 21st century. Although coal is composed predominantly of organic matter, inorganic constituents in coal commonly attract more attention and can ultimately determine how the coal will be used.

Biomass for energy: supply prospects.

Abstract: Biomass for energy can be obtained from residues of ongoing agricultural and forest-product industries, from harvesting forests, and from dedicated plantations. The harvesting of forests for biomass is likely to be limited by environmental concerns. Over the next couple of decades new bioenergy industries will be launched primarily using residues as feedstocks. Subsequently, the industrial base will shift to plantations, the largest potential source of biomass. The most promising sites for plantations are deforested and otherwise degraded lands in developing countries and excess croplands in the industrialized countries. Revenues from the sale of biomass crops grown on plantations established on degraded lands can help finance the restoration of these lands. Establishing plantations on excess croplands can be a new livelihood to farmers who might otherwise abandon their land because of foodcrop overproduction. In either case, biomass plantations can, with careful planning, substantially improve these lands ecologically relative to their present uses. But a substantial and sustained research and development effort is needed to ensure the realization and sustainability of high yields under a wide range of growing conditions. Moreover, the establishment and maintenance of biomass plantations must be carried out in the framework of sustainable economic development in ways thatmore » are acceptable and beneficial to the local people. Ultimately, land and water resource constraints will limit the contributions that biomass can make as an energy source in advanced societies. But biomass energy can nevertheless make major contributions to sustainable development before these limits are reached, if biomass is grown productively and sustainably and is efficiently converted to modern energy carriers that are used in energy-efficient end-use technologies. 88 refs., 5 figs., 13 tabs.« less

Methods and apparatus for dispensing a consumable energy source to a vehicle

Abstract: Methods and apparatus are disclosed for dispensing a consumable energy soe, such as electrical power or liquid fuel, to a vehicle. A vehicle includes apparatus for coupling the vehicle to a dispenser of the consumable energy source. The vehicle further includes a memory and a coupler for bidirectionally coupling the memory to the dispenser of the consumable energy source for transferring information therebetween. Embodiments of the invention describe the transfer of an indicia from the memory to a remote site for use in accounting for an amount of the consumable energy source that is input to the vehicle. Messages and other information, such as advertisements, can be input to the vehicle while coupled to the dispenser. A display is provided for displaying the information to an operator. A data entry device, such as a keyboard, may also be provided for originating information within the vehicle for transmission to a remote site.

Mechanistic Aspects of the Formation of Hydrocarbons and Alcohols from CO Hydrogenation

Abstract: In 1973 the oil crisis prompted considerable world interest in the production of synfuels which, as a result, led to the development of the Mobil Methanol to Gasoline Process [1] and more recently to the Shell Middle Distillate Process [2]. Synfuels have been a subject of both scientific and political interest for most of the 20th century. With the recent Gulf crisis, which has resulted in a surge in crude oil prices, it is clear that the search to find economic alternatives to the use of petroleum as an energy source will continue. This observation is based on the fact that the world reserves of coal and natural gas far exceed those of oil, and this fact alone implies that the conversion of coal and natural gas to transportation fuels is almost certain to become more widespread within the next 20 years.

Bipolar coagulation device

Abstract: A bipolar coagulation instrument comprising three concentric tubes, wherein the outer tube is generally rigid, the central tube is an electrically conductive metal in communication with an energy source, and the inner tube is electrically non-conductive. The distal end of the central tube extends beyond the distal end of the outer tube and functions as an electrode and first jaw of the coagulation instrument. The inner tube, which is translationally movable by an operator, has extending therethrough within its lumen a conductive lead whose distal end protrudes distally therefrom beyond the distal end of the outer tube and is configured at its distal end to function as an opposing second jaw to the first jaw. Translational movement of the inner tube distally forces the second electrode jaw toward the first electrode jaw to thereby bring the first and second jaws into contact with each other. Thereafter, when current is introduced to the conductive lead and to the central tube, the resulting electrode jaws perform to cauterize tissue at the treatment site when such tissue is grasped within the jaws which are then closed. Subsequent proximal translational movement of the inner tube releases the distal end of the conductive lead which is the second jaw of the instrument from the distal end of the central tube which is the first jaw of the instrument. A coagulation instrument is thereby provided whose outer tube has a diameter of less than about three millimeters, thereby permitting its travel within the lumen of a minimally sized laparoscope, endoscope or similar device.

Ultrasonic transmission apparatus

Abstract: A horn (12) connectable to an energy source (88) to amplify ultrasound displacement is connected to a transmitter (14) formed of material having relatively high mechanical Q for transmitting ultrasonic energy therethrough at a frequency f, the transmitter having a horn-shaped configuration of length that is a multiple of a half-wavelength μ/2, and preferably this horn-shaped configuration is comprised of multiple horn segments (16a and 16b) each of a length substantially equal to a multiple of μ/2, where μ = c/f (c is the speed of sound in the high Q material). The transmitter has a proximal end of cross-sectional diameter D1 connected to the horn and a distal end of cross-sectional diameter D2, where D1 > D2. Ultrasonic energy transmitted through the transmitter drives a tip which is coupled to the transmitter by means of a flexible connector (20).

Yeast Sugar Transporters

Abstract: Transport of sugars is a fundamental property of all eukaryotic cells. Of particular importance is the uptake of glucose, a preferred carbon and energy source. The rate of glucose utilization in yeast is often dictated by the activity and concentration of glucose transporters in the plasma membrane. Given the importance of transport as a site of control of glycolytic flux, the regulation of glucose transporters is necessarily complex. The molecular analysis of these transporters in Saccharomyces has revealed the existence of a multigene family of sugar carriers. Recent data have raised the question of the actual role of all of these proteins in sugar catabolism, as some appear to be lowly expressed, and point mutations of these genes may confer pleiotropic phenotypes, inconsistent with a simple role as catabolic transporters. The transporters themselves appear to be intimately involved in the process of sensing glucose, a model for which there is growing support.

Degradation of nitrobenzene by a Pseudomonas pseudoalcaligenes.

Abstract: A Pseudomonas pseudoalcaligenes able to use nitrobenzene as the sole source of carbon, nitrogen, and energy was isolated from soil and groundwater contaminated with nitrobenzene. The range of aromatic substrates able to support growth was limited to nitrobenzene, hydroxylaminobenzene, and 2-aminophenol. Washed suspensions of nitrobenzene-grown cells removed nitrobenzene from culture fluids with the concomitant release of ammonia. Nitrobenzene, nitrosobenzene, hydroxylaminobenzene, and 2-aminophenol stimulated oxygen uptake in resting cells and in extracts of nitrobenzene-grown cells. Under aerobic and anaerobic conditions, crude extracts converted nitrobenzene to 2-aminophenol with oxidation of 2 mol of NADPH. Ring cleavage, which required ferrous iron, produced a transient yellow product with a maximum A380. In the presence of NAD, the product disappeared and NADH was produced. In the absence of NAD, the ring fission product was spontaneously converted to picolinic acid, which was not further metabolized. These results indicate that the catabolic pathway involves the reduction of nitrobenzene to nitrosobenzene and then to hydroxylaminobenzene; each of these steps requires 1 mol of NADPH. An enzyme-mediated Bamberger-like rearrangement converts hydroxylaminobenzene to 2-aminophenol, which then undergoes meta ring cleavage to 2-aminomuconic semialdehyde. The mechanism for release of ammonia and subsequent metabolism are under investigation.

Erythrocyte Docosahexaenoic Acid Correlates with the Visual Response of Healthy, Term Infants

Abstract: Recent studies have reported that formulafed preterm infants score lower on visual and developmental tests relative to breast-fed preterm infants. This phenomenon has been associated with the presence of docosahexaenoic acid (DHA), an omega-3 fatty acid, in breast milk and its absence from infant formula. To investigate the possibility that DHA status of healthy, term infants is also related to neuronal function of the visual pathway, we studied the erythrocyte fatty acid profiles of 16 infants at 22.3 ± 3.9 wk of age and related these to maturity of the visual pathway as assessed by visual-evoked potentials. Healthy, term infants fed breast milk had better visual-evoked potential acuity (p < 0.05) and higher DHA levels (p < 0.001) than infants who received infant formula as their major energy source. There was a positive correlation between erythrocyte DHA and visual-evoked potential acuity (p < 0.01). The data are preliminary and the long-term effects as yet unknown. However, our results suggest that there is an urgent need to evaluate the dietary fatty acid supply of formula-fed term infants.

Fruit and vegetables

Abstract: Unlike other chilled perishable foods that are modified atmosphere packed, fresh fruit and vegetables continue to respire after harvesting, and consequently any subsequent packaging must take into account this respiratory activity. Respiration is a very complex biochemical phenomenon whereby carbohydrates, polysaccharides, organic acids and other energy sources are metabolised into simpler molecules with the production of heat. The products of aerobic respiration are carbon dioxide (CO2) and water vapour, whereas fermentation products such as ethanol, acetaldehyde and organic acids are produced during anaerobic respiration. Respiration is affected by numerous intrinsic properties of fresh produce as well as various extrinsic factors, but, generally speaking, the achievable shelf-life of modified atmosphere packed produce is inversely proportional to respiration rate (sections 6.2.2 and 6.3).

Natural Gas Hydrates of the Prudhoe Bay and Kuparuk River Area, North Slope, Alaska

Abstract: Gas hydrates are crystalline substances composed of water and gas, mainly methane, in which a solid-water lattice accommodates gas molecules in a cage-like structure, or clathrate. These substances commonly have been regarded as a potential unconventional source of natural gas because of their enormous gas-storage capacity. Significant quantities of naturally occurring gas hydrates have been detected in many regions of the Arctic, including Siberia, the Mackenzie River Delta, and the North Slope of Alaska. On the North Slope, the methane-hydrate stability zone is areally extensive beneath most of the coastal plain province and has thicknesses greater than 1000 m in the Prudhoe Bay area. Gas hydrates have been inferred to occur in 50 North Slope exploratory and production wells on the basis of well-log responses calibrated to the response of an interval in a well where gas hydrates were recovered in a core by ARCO and Exxon. Most North Slope gas hydrates occur in six laterally continuous lower Tertiary sandstones and conglomerates; all these gas hydrates are geographically restricted to the area overlying the eastern part of the Kuparuk River oil field and the western part of the Prudhoe Bay oil field. The volume of gas within these gas hydrates is estimated to be about 1.0 × 1012 to 1.2 × 1012 m3 (37 to 44 tcf), or about twice the volume of conventional gas in the Prudhoe Bay field. Geochemical analyses of well samples suggest that the inferred hydrates probably contain a mixture of deep-source thermogenic gas and shallow, microbial gas that was either directly converted to gas hydrate or first concentrated in existing traps and later converted to gas hydrate. The thermogenic gas probably migrated from deeper reservoirs along the same faults thought to have been migration pathways for the large volumes of heavy oil that occur in the shallow reservoirs of this area.

Anaerobic transformation of 2,4,6-trinitrotoluene (TNT).

Abstract: A sulfate-reducing bacterium using trinitrotoluene (TNT) as the sole nitrogen source was isolated with pyruvate and sulfate as the energy sources. The organism was able to reduce TNT to triaminotoluene (TAT) in growing cultures and cell suspensions and to further transform TAT to still unknown products. Pyruvate, H2, or carbon monoxide served as the electron donors for the reduction of TNT. The limiting step in TNT conversion to TAT was the reduction of 2,4-diamino-6-nitrotoluene (2,4-DANT) to triaminotoluene. The reduction proceeded via 2,4-diamino-6-hydroxylaminotoluene (DAHAT) as an intermediate. The intermediary formation of DAHAT was only observed in the presence of carbon monoxide or hydroxylamine, respectively. The reduction of DAHAT to triaminotoluene was inhibited by both CO and NH2OH. The inhibitors as well as DANT and DAHAT significantly inhibited sulfide formation from sulfite. The data were taken as evidence for the involvement of dissimilatory sulfite reductase in the reduction of DANT and/or DAHAT to triaminotoluene. Hydrogenase purified from Clostridium pasteurianum and carbon monoxide dehydrogenase partially purified from Clostridium thermoaceticum also catalyzed the reduction of DANT in the presence of methyl viologen or ferredoxin, however, as the main reduction product DAHAT rather than triaminotoluene was formed. The findings could explain the function of CO as an electron donor for the DANT reduction (to DAHAT) and the concomitant inhibitory effect of CO on triaminotoluene formation (from DAHAT) by the inhibition of sulfite reductase.(ABSTRACT TRUNCATED AT 250 WORDS)

Are hydroelectric reservoirs significant sources of greenhouse gases

Abstract: Estimates suggest that, per unit of energy produced, greenhouse-gas flux to the atmosphere from some hydroelectric reservoirs may be significant compared to greenhouse-gas emission by fossil-fuelled electricity generation. Greenhouse gases (CO[sub 2] and CH[sub 4]) are produced during bacterial decomposition of flooded peat and forest biomass. The amount emitted will be positively related to the area flooded. Early data from hydroelectric reservoirs in northern Canada support this hypothesis. Our hypothesis is based primarily on two of our past studies which show that both upland forests and peatlands are sites of intense microbial decomposition and greenhouse-gas production when they become covered with water. During the summer of 1992, the first preliminary data were obtained that support our hypothesis. At 12 sampling locations on the LaGrande II-Boyd[sub S]akami Reservoir complex in northern Quebec, both the CO[sub 2] and CH[sub 4] were found to be evading to the atmosphere. CO[sub 2] concentrations were 2-3 times above atmospheric equilibrium at all sampling sites. This is in contrast to two large lakes, Nipigon and Superior, where CO[sub 2] was being absorbed from the atmosphere throughout the ice-free season. Surface CH[sub 4] concentrations were 0.05-1.1 [mu]mol L[sup -1] with most sites having concentrations higher than in natural, stratified Canadian shield lakes. Further measurements are required to determine annual fluxes. (19 refs., 3 figs., 2 tabs.)

Decay of equatorial ring current ions and associated aeronomical consequences

Abstract: The decay of the major ion species which constitute the ring current is studied by solving the time evolution of their distribution functions during the recovery phase of a moderate geomagnetic storm. In this work, only equatorially mirroring particles are considered. Particles are assumed to move subject to E x B and gradient drifts. They also experience loses along their drift paths. Two loss mechanisms are considered: charge exchange with neutral hydrogen atoms and Coulomb collisions with thermal plasma in the plasmasphere. Thermal plasma densities are calculated with a plasmaspheric model employing a time-dependent convection electric field model. The drift-loss model successfully reproduces a number of important and observable features in the distribution function. Charge exchange is found to be the major loss mechanism for the ring current ions; however the important effects of Coulomb collisions on both the ring current and thermal populations are also presented. The model predicts the formation of a low-energy (less than 500 eV) ion population as a result of energy degradation caused by Coulomb collision of the ring current ions with the plasmaspheric electrons; this population may be one source of the low-energy ions observed during active and quiet periods in the inner magnetosphere. The energy transferred to plasmaspheric electrons through Coulomb collisions with ring current ions is believed to be the energy source for the electron temperature enhancement and the associated 6300 A (stable auroral red (SAR) arc) emission in the subauroral region. The calculated energy deposition rate is sufficient to produce a subauroral electron temperature enhancement and SAR arc emissions that are consistent with observations of these quantities during moderate magnetic activity levels.

Method and apparatus for time-division plasma chopping in a multi-channel plasma processing equipment

Abstract: A multi-switch processing methodology and a multi-channel time-division plasma chopping device (10) for in-situ plasma-assisted semiconductor wafer processing associated with a plasma and/or photochemical processing equipment. The device (10) comprises a main transfer channel (72) associated with the processing reactor for transferring process gas and activated plasma mixtures into the reactor. A plurality of gas discharge channels (18, 22, 26, and 30) associate with the main transfer channel (72) for independently directing various gases and activated plasma combinations to main transfer channel (72). Process excitation sources (16, 20, 24 and 28) associate with at least one of said gas discharge or activation channels to independently and selectively activate process gases and to control gas activation and flow from the discharge channels to the main transfer channel (72). The method of the present invention performs multi-channel time-division plasma chopping by independently and selectively generating plasma or activated species using a plurality of remote plasma generation process energy sources (16, 20, 24, and 28) associated with the semiconductor wafer fabrication reactor.