Showing papers on "Energy source published in 1987"

Why nature chose phosphates

Abstract: Phosphate esters and anhydrides dominate the living world but are seldom used as intermediates by organic chemists. Phosphoric acid is specially adapted for its role in nucleic acids because it can link two nucleotides and still ionize; the resulting negative charge serves both to stabilize the diesters against hydrolysis and to retain the molecules within a lipid membrane. A similar explanation for stability and retention also holds for phosphates that are intermediary metabolites and for phosphates that serve as energy sources. Phosphates with multiple negative charges can react by way of the monomeric metaphosphate ion PO3- as an intermediate. No other residue appears to fulfill the multiple roles of phosphate in biochemistry. Stable, negatively charged phosphates react under catalysis by enzymes; organic chemists, who can only rarely use enzymatic catalysis for their reactions, need more highly reactive intermediates than phosphates.

Transformation of toluene and benzene by mixed methanogenic cultures

Abstract: The aromatic hydrocarbons toluene and benzene were anaerobically transformed by mixed methanogenic cultures derived from ferulic acid-degrading sewage sludge enrichments. In most experiments, toluene or benzene was the only semicontinuously supplied carbon and energy source in the defined mineral medium. No exogenous electron acceptors other than CO2 were present. The cultures were fed 1.5 to 30 mM unlabeled or 14C-labeled aromatic substrates (ring-labeled toluene and benzene or methyl-labeled toluene). Gas production from unlabeled substrates and 14C activity distribution in products from the labeled substrates were monitored over a period of 60 days. At least 50% of the substrates were converted to CO2 and methane (greater than 60%). A high percentage of 14CO2 was recovered from the methyl group-labeled toluene, suggesting nearly complete conversion of the methyl group to CO2 and not to methane. However, a low percentage of 14CO2 was produced from ring-labeled toluene or from benzene, indicating incomplete conversion of the ring carbon to CO2. Anaerobic transformation pathways for unlabeled toluene and benzene were studied with the help of gas chromatography-mass spectrometry. The intermediates detected are consistent with both toluene and benzene degradation via initial oxidation by ring hydroxylation or methyl oxidation (toluene), which would result in the production of phenol, cresols, or aromatic alcohol. Additional reactions, such as demethylation and ring reduction, are also possible. Tentative transformation sequences based upon the intermediates detected are discussed.

Comparison of methods for measuring kerogen pyrolysis rates and fitting kinetic parameters

Abstract: We determine rates of product evolution during pyrolysis of several petroleum source rocks and isolated kerogens by nonisothermal techniques, including Rock Eval pyrolysis-MS/MS The resulting data are analyzed by nonlinear regression and simpler correlation techniques in terms of discrete and Gaussian distributed activation energy models We find that temperatures measured by standard Rock Eval analysis are too low by about 40/sup 0/C, resulting in kinetic expressions that are much too fast Proper temperature calibration eliminates this problem We explore the sensitivity of the kinetic parameters and extrapolation to geologic heating rates to uncertainty in the temperature calibration We find that the discrete distribution model provides a superior fit to the laboratory data and probably a more reliable extrapolation to geological heating rates We also assess how differences among kinetics for individual species relate to the activation energy distributions required for total hydrocarbon evolution Kinetics from Rock Eval pyrolysis predict hydrocarbon generation rates intermediate between kerogen decomposition and oil expulsion during hydrous pyrolysis, but slight differences in activation energies result in similar predictions for a geological heating rate Predictions for type I kerogens fall at the high end, but within the range, of oil generation temperatures predicted for type II kerogensmore » 18 refs, 7 figs, 5 tabs« less

Energy for a Sustainable World

Abstract: A team of members from Brazil Sweden India and the US have conducted an energy analysis which focused on energy demand rather than energy supply. This end-use analysis is entitled the End Use Global Energy Project (EUGEP). The EUGEP global energy scenario for 2020 indicates a per capita energy use in industrialized countries of almost 50% lower than what it was in 1980 (3.2 kilowatts/person vs. 6.3 kilowatts/person). The scenario assumes a widespread shift from the inefficient noncommercial fuels to modern energy technologies in high efficiency applications. Other assumptions include limited growth in nuclear power a balanced energy supply mix and limits in use of fossil fuels especially coal. It finds that a mean 1.3 kilowatts/person could support the living standard present in western Europe in the late 1980s. The EUGEP scenario depicts a society in which global energy use is only 10% higher than it was in the late 1980s despite an increase in the population to 7 billions people compared with an increase of over 100% for conventional projections. This energy analysis serves only as an illustration of the technically possible. It communicates to policymakers that they have a choice. The analysts present case studies from Sweden and the US. They also address global energy and use as it applies in developing countries and market-oriented countries.

The ionosphere as a fully adequate source of plasma for the Earth's magnetosphere

Abstract: The ionospheric contribution of the polar wind and cleft ion fountain at energies less than 10 eV has been added to previously measured sources; this total ion outflow has then been used to calculate the resulting ion density in the different internal regions of the earth's magnetosphere: plasmasphere, plasma trough, plasma sheet, and magnetotail lobes. Using estimated volumes for these regions and an ion residence time characteristic of each region, it is found that the observed magnetospheric densities can be attained in all cases with no contribution from the solar wind plasma. In the case of the plasma sheet the ionospherically supplied density is more than enough to match the observations and even suggests an invisible component of low-energy plasma (less than 10 eV) which has never been observed. A detailed comparison between the calculated ionospheric source effects in the plasma sheet and those recently measured by ISEE shows excellent agreement and suggests a direct polar low-energy ion source for the plasma sheet which has remained unmeasured because of spacecraft potential effects. Although the solar wind is clearly the earth's magnetospheric energy source and energetic solar wind ions are observed in the magnetosphere, these calculations suggest the possibility that the ionospheric source alone is sufficient to supply the entire magnetospheric plasma content under all geomagnetic conditions.

Occurrence, absorption and metabolism of short chain fatty acids in the digestive tract of mammals.

Abstract: Short chain fatty acids (SCFA) also named volatile fatty acids, mainly acetate, propionate and butyrate, are the major end-products of the microbial digestion of carbohydrates in the alimentary canal. The highest concentrations are observed in the forestomach of the ruminants and in the large intestine (caecum and colon) of all the mammals. Butyrate and caproate released by action of gastric lipase on bovine milk triacylglycerols ingested by preruminants or infants are of nutritional importance too. Both squamous stratified mucosa of rumen and columnar simple epithelium of intestine absorb readily SCFA. The mechanisms of SCFA absorption are incompletely known. Passive diffusion of the unionized form across the cell membrane is currently admitted. In the lumen, the necessary protonation of SCFA anions could come first from the hydration of CO2. The ubiquitous cell membrane process of Na+-H+ exchange can also supply luminal protons. Evidence for an acid microclimate (pH = 5.8-6.8) suitable for SCFA-protonation on the surface of the intestinal lining has been provided recently. This microclimate would be generated by an epithelial secretion of H+ ions and would be protected by the mucus coating from the variable pH of luminal contents. Part of the absorbed SCFA does not reach plasma because it is metabolized in the gastrointestinal wall. Acetate incorporation in mucosal higher lipids is well-known. However, the preponderant metabolic pathway for all the SCFA is catabolism to CO2 except in the rumen wall where about 80% of butyrate is converted to ketone bodies which afterwards flow into bloodstream. Thus, SCFA are an important energy source for the gut mucosa itself.

Coronary hemodynamics and myocardial metabolism of lactate, free fatty acids, glucose, and ketones in patients with septic shock.

Abstract: To investigate disturbances in the coronary circulation and myocardial metabolism during septic shock, we examined coronary sinus blood flow and myocardial substrate extraction in 40 patients with septic shock and 13 control patients. Patients with coronary artery disease were excluded from this study. The global hemodynamic pattern of the septic patients was characterized by a lower stroke volume, despite an elevated cardiac index. Coronary sinus blood flow was high (187 +/- 47 vs 130 +/- 21 ml/min in the control group, p less than .001) due to marked coronary vasodilation, especially in the subgroup of nonsurvivors. In contrast to the control group, myocardial lactate uptake was elevated, while that of free fatty acids, glucose, and ketone bodies was diminished in patients with septic shock. These findings were especially prominent in the nonsurvivors. Expressed as oxygen equivalents, the contribution of free fatty acids as an energy source of the myocardium was markedly diminished in septic patients (12% vs 54% in the control group, p less than .005), while that of lactate was increased (36% vs 12%, p less than .01). The observed shift in myocardial substrate extraction was associated with a discrepancy between measured myocardial oxygen consumption and that calculated chemically from commonly available exogenous substrates: 41% of myocardial oxygen consumption was not explained by the utilization of commonly available substrates extracted from coronary circulation in all patients with septic shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Deep-sea hydrocarbon seep communities: evidence for energy and nutritional carbon sources

Abstract: Mussels, clams, and tube worms collected in the vicinity of hydrocarbon seeps on the Louisiana slope contain mostly "dead" carbon, indicating that dietary carbon is largely derived from seeping oil and gas. Enzyme assays, elemental sulfur analysis, and carbon dioxide fixation studies demonstrate that vestimentiferan tube worms and three clam species contain intracellular, autotrophic sulfur bacterial symbionts. Carbon isotopic ratios of 246 individual animal tissues were used to differentiate heterotrophic (8(13)C = -14 to -20 per mil), sulfur-based (8(13)C = -30 to -42 per mil), and methane-based (8(13)C = <-40 per mil) energy sources. Mussels with symbiotic methanotrophic bacteria reflect the carbon isotopic composition of the methane source. Isotopically light nitrogen and sulfur confirm the chemoautotrophic nature of the seep animals. Sulfur-based chemosynthetic animals contain isotopically light sulfur, whereas methane-based symbiotic mussels more closely reflect the heavier oceanic sulfate pool. The nitrogen requirement of some seep animals may be supported by nitrogen-fixing bacteria. Some grazing neogastropods have isotopic values characteristic of chemosynthetic animals, suggesting the transfer of carbon into the background deep-sea fauna.

Intravascular ultrasonic catheter/probe and method for treating intravascular blockage

Abstract: Apparatus and method are disclosed for treating atherosclerotic plaque and thromboses by the application of ultrasonic energy to a site of intravascular blockage The ultrasonic apparatus includes a solid wire probe having a bulbous tip at one end and coupled to an ultrasonic energy source at the other end, the probe being carried within a hollow catheter The catheter and probe are inserted into a blood vessel and are advanced to the site of a stenosis, where the probe is extended from the catheter and caused to vibrate ultrasonically, resulting in the destruction of the arterial plaque The ultrasonic apparatus includes a fitting for delivering a radiographic contrast solution to the probe tip by flowing the solution into the catheter, the contrast fluid being released into the blood vessel to assist in positioning the apparatus and determining the effectiveness of treatment A physiologic solution may also be carried to the probe tip by flowing the solution through the catheter, thereby controlling the temperature of the probe tip during the procedure

Wind Energy Resource Atlas of the United States

Abstract: This atlas estimates wind energy resource for the United States and its territories, and indicates general areas where a high wind resource may exist. This information is valuable to wind energy developers and potential wind energy users because it allows them to choose a general area of estimated high wind resource for more detailed examination.

Myocardial metabolism of free fatty acids. Studies with 14C-labeled substrates in humans.

Abstract: Free fatty acids are considered to be the major energy source for the myocardium. To investigate the metabolic fate of this substrate in humans, 24 subjects underwent coronary sinus and arterial catheterization. 13 subjects were healthy volunteers and 11 subjects had symptoms of ischemic heart disease. [1-14C]oleate or [1-14C]palmitate bound to albumin was infused at a constant rate of 25 microCi/h. Oxidation was determined by measuring the 14CO2 production. The data demonstrated that a high percentage (84 +/- 17%) of the palmitate and oleate extracted by the myocardium underwent rapid oxidation. A highly significant correlation was present between the arterial level and the amount oxidized (r = 0.82, P less than 0.001 for palmitate; r = 0.77, P less than 0.001 for oleate). The isotope extraction ratio was greater than the chemical extraction ratio. This difference of 6 +/- 2 nmol/ml of blood in the young normal subjects was significantly less than the 12 +/- 4 nmol/ml observed in the ischemic heart disease patients (P less than 0.001).

The Synoptic Setting and Possible Energy Sources for Mesoscale Wave Disturbances

Abstract: Published data on 13 cases of mesoscale wave disturbances and their environment were examined to isolate common features for these cases and to determine possible energy sources for the waves. These events are characterized by either a singular wave of depression or wave packets with periods of 1-4 h, horizontal wavelengths of 50-500 km, and surface-pressure perturbation amplitudes of 0.2-7.0 mb. These wave events are shown to be associated with a distinct synoptic pattern (including the existence of a strong inversion in the lower troposphere and the propagation of a jet streak toward a ridge axis in the upper troposphere) while displaying little correlation with the presence of convective storm cells. The observed development of the waves is consistent with the hypothesis that the energy source needed to initiate and sustain the wave disturbances may be related to a geostrophic adjustment process associated with upper-tropospheric jet streaks.

Associations between 1980 U.S. mortality rates and alternative measures of airborne particle concentration.

Abstract: We analyzed the 1980 U.S. vital statistics and available ambient air pollution data bases for sulfates and fine, inhalable, and total suspended particles. Using multiple regression analyses, we conducted a cross-sectional analysis of the association between various particle measures and total mortality. Results from the various analyses indicated the importance of considering particle size, composition, and source information in modeling of particle pollution health effects. Of the independent mortality predictors considered, particle exposure measures related to the respirable and/or toxic fraction of the aerosols, such as fine particles and sulfates, were most consistently and significantly associated with the reported SMSA-specific total annual mortality rates. On the other hand, particle mass measures that included coarse particles (e.g., total suspended particles and inhalable particles) were often found to be nonsignificant predictors of total mortality. Furthermore, based on the application of fine particle source apportionment, particles from industrial sources (e.g., from iron/steel emissions) and from coal combustion were suggested to be more significant contributors to human mortality than soil-derived particles.

Tomographic imaging of three‐phase flow experiments

Abstract: The medical x‐ray computerized tomography (CT) scanner has proved to be a useful tool for studies of fluid flow in porous media, with particular applications in reservoir engineering and enhanced oil recovery. This paper explains how CT is used to measure the volume fraction of pore space occupied by up to three discrete phases, such as oil, water, and gas. The image processing system, x‐ray transparent high‐pressure flow equipment, choice of fluid dopants, and x‐ray energies are described for scanning of core flood experiments. Examples are given of tertiary miscible carbon dioxide displacements in Berea sandstone.

Wave energy and intertidal productivity.

Abstract: In the northeastern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Postelsia palmaeformis, can produce > 10 kg of dry matter, or 1.5 × 108 J, per m2 in a good year. Extraordinarily productive organisms such as Postelsia are restricted to wave-beaten sites. Intertidal organisms cannot transform wave energy into chemical energy, as photosynthetic plants transform solar energy, nor can intertidal organisms “harness” wave energy. Nonetheless, wave energy enhances the productivity of intertidal organisms. On exposed shores, waves increase the capacity of resident algae to acquire nutrients and use sunlight, augment the competitive ability of productive organisms, and protect intertidal residents by knocking away their enemies or preventing them from feeding.

Energy yields for hydrogen cyanide and formaldehyde syntheses: the HCN and amino acid concentrations in the primitive ocean.

Abstract: Prebiotic electric discharge and ultraviolet light experiments are usually reported in terms of carbon yields and involve a large input of energy to maximize yields. Experiments using lower energy inputs are more realistic prebiotic models and give energy yields which can be used to estimate the relative importance of the different energy sources on the primitive earth.

Symbiosis of methylotrophic bacteria and deep-sea mussels

Abstract: Recently, dense assemblages of seep mussels and other benthic invertebrates resembling hydrothermal vent communities were found associated with reducing sediments at hypersaline seeps in the abyssal gulf of Mexico1. A symbiotic association with sulphur-oxidizing chemolithoautotrophic bacteria, similar to those recently reported (for review see ref. 2), was postulated for the seep mussel. However, the very negative δC13 values reported for the mussels (-74%‰) (ref. 3) suggested that these symbioses were different from those reported for bivalves from hydrothermal vents and reducing sediments (where δC13 ranges from -23 to -34‰ refs 4,5). Here, we present microscopical and enzymatic evidence supporting the hypothesis that methylotrophs, bacteria capable of using reduced C-1 compounds as their carbon and energy sources, occur as intracellular symbionts of the seep mussel.

Method for cleanup processing chamber and vacuum process module

Abstract: A process module having remote plasma and in situ plasma generators, and a radiant heater, which represent three separate energy sources. The three sources can be used singly or in any combination and can be separately controllable.

The role of ring current O+ in the formation of stable auroral red arcs

Abstract: Observations of thermal and energetic ion populations by the Dynamics Explorer 1 satellite in the magnetospheric energy source region as well as nearly simultaneous Langmuir probe measurements of enhanced electron temperatures by Dynamics Explorer 2 within the stable auroral red (SAR) arc at F region heights are used to examine the role of heavy ions in the formation of SAR arcs. It is found that sufficient energy is transferred to the electron gas at high altitudes via Coulomb collisions between the observed ring current ions and thermal electrons to support the enhanced F region electron temperatures measured on these field lines. The latitudinal variation in the electron heating rates calculated using observed ion populations is consistent with the observed variation in electron temperature across the SAR arc. In all cases, ring current O(+) is the major source of energy for the SAR arcs.

Apparent inability of channel catfish to utilize dietary mono- and disaccharides as energy sources.

Abstract: Purified diets containing equivalent amounts of glucose, maltose, fructose, sucrose, corn starch and dextrin were fed to fingerling channel catfish (Icatalurus punctatus) to compare the growth responses to these various carbohydrates. The best growth response was achieved with dextrin and the next best with corn starch. Fish grew at the same rate when glucose, maltose or sucrose was the only dietary carbohydrate source. Dietary fructose resulted in the lowest growth rate. Feed efficiency and percent retained energy values followed the same pattern as growth rates. These data suggest that the catfish is apparently unable to utilize dietary mono- and disaccharides as energy sources. Oral carbohydrate tolerance tests using glucose, maltose, fructose, sucrose and dextrin were conducted with larger channel catfish. Oral glucose and maltose resulted in a persistent hyperglycemia indicative of a diabetic-like status. Fructose appeared to be poorly absorbed from the intestinal tract and did not appear to be converted to glucose. Oral administration of sucrose was followed by a gradual increase in plasma glucose, with no detectable fructose being absorbed until the 6-h period. Oral dextrin resulted in less than a two-fold increase in plasma glucose, which remained constant from 2 to 4 h after administration and then declined. These observations are consistent with the hypothesis that certain fishes, including the channel catfish, resemble diabetic animals by having insufficient insulin for maximum carbohydrate utilization.

Co‐metabolism of citrate and glucose by Leuconostoc spp.: effects on growth, substrates and products

Abstract: Growth, substrate utilization and product formation from glucose, citrate and a mixture of both substrates were studied in four strains of Leuconostoc spp. Citrate was not used as an energy source but was rapidly metabolized when glucose was present. The predictable amounts of D-lactate and ethanol were produced from glucose, although strains X2 and 7–1 gave lower yields of ethanol. In strains NCW1, S3 and X2, co-metabolism of both glucose and citrate resulted in stimulation of growth, decreased uptake of glucose, increased acetate and D-lactate production and lack of ethanol production compared with that obtained with glucose alone. Strain 7–1 showed only growth stimulation and increased acetate production. Diacetyl, acetoin or 2, 3-butylene glycol were not detected. In strain NCW1 citrate had a slightly inhibitory effect on the enzymes of the ‘ethanol’ leg of glucose metabolism. Except for strain 7–1, these observations are consistent with a switch in glucose metabolism from ethanol to acetate production.

Seaweed Cultivation for Renewable Resources

Abstract: Introduction and Foreword (P. Benson, K. Bird). 1. Energy from Biomass: The Historical Record (P. Neushul). 2. Ocean Farming of Macrocystis, the Problems and Non-Problems (W.J. North). 3. Nearshore Kelp Cultivation, Yield and Genetics (M. Neushul, B.W.W. Harger). 4. Optimizing Biomass Production on Marine Farms (V.A. Gerard). 5. Laminaria Cultivation in Far East and North America (B.H. Brinkhuis, H.G. Levine, C.G. Schlenk, S. Tobin). 6. Some Remarks on the Kelp Cultivation Industry of China (C.K. Tseng). 7. The Biology of Commercially Important Tropical Algae (C.J. Dawes). 8. Cultivation of Gracilaria and Other Macroalgae in Florida for Energy Production (M.D. Hanisak). 9. Tissue Culture of Seaweeds (M. Polne-Fuller, A. Gibor). 10. Nitrogen Fixation in Marine Communities and its Potential Role in Seaweed Cultivation (E.J. Phlips). 11. Biological Gasification of Marine Algae (D.P. Chynoweth, K.F. Fannin, V.J. Srivastava). 12. Microbial Degradation of Marine Biomass (J. Forro). 13. Cost Analyses of Energy from Marine Biomass (K.T. Bird). 14. Commercialization Strategy for Nori Culture in Puget Sound, Washington (T.F. Mumford, Jr.). Conclusions and Recommendations (K. Bird, P. Benson). Technical Reports. Index.

Regulation and roles for alternative pathways of hexose metabolism in plants

Abstract: Plant cells have two cytoplasmic pathways of glycolysis and gluconeogenesis for the reversible interconversion of fructose 6-phosphate (F-6-P) and fructose 1,6-bisphosphate (F-1,6-P2). One pathway is described as a maintenance pathway that is catalyzed by a nucleotide triphosphate-dependent phosphofructokinase (EC 2.7.1.11; ATP-PFK) glycolytically and a F-1,6 bisphosphatase (EC 3.1.3.11) gluconeogenically. These are non-equilibrium reactions that are energy consuming. The second pathway, described as an adaptive pathway, is catalyzed by a readily reversible pyrophosphate-dependent phosphofructokinase (EC 2.7.1.90; PP-PFK) in an equilibrium reaction that conserves energy through the utilization and the synthesis of pyrophosphate. A constitutive regulator cycle is also present for the synthesis and hydrolysis of fructose 2,6-bisphosphate (F-2,6-P2) via a 2-kinase and a 2-phosphatase, respectively. The pathway catalyzed by the ATP-PFK and F-1,6-bisphosphatase, the maintenance pathway, is fairly constant in maximum activity in various plant tissues and shows less regulation by F-2,6-P2. Plants use F-2,6-P2 initially to regulate the adaptive pathway at the reversible PPi-PFK step. The adaptive pathway, catalyzed by PPi-PFK, varies in maximum activity with a variety of phenomena such as plant development or changing biological and physical environments. Plants can change F-2,6-P2 levels rapidly, in less than 1 min when subjected to rapid environmental change, or change levels slowly over periods of hours and days as tissues develop. Both types of change enable plants to cope with the environmental and developmental changes that occur during their lifetimes. The two pathways of sugar metabolism can be efficiently linked by the cycling of uridylates and pyrophosphate required for sucrose breakdown via a proposed sucrose synthase pathway. The breakdown of sucrose via the sucrose synthase pathway requires half the net energy of breakdown via the invertase pathway. Pyrophosphate occurs in plant tissues as a substrate pool for biosynthetic reactions such as the PPi-PFK or uridine diphosphate glucose pyrophosphorylase (EC 2.7.7.9; UDPG pyrophosphorylase) that function in the breakdown of imported sucrose. Also, pyrophosphate links the two glycolytic/gluco-neogenic pathways; and in a reciprocal manner pyrophosphate is produced as an energy source during gluconeogenic carbon flow from F-1,6-P2 toward sucrose synthesis.

In-situ coal drying

Abstract: A method for upgrading coal in-situ is disclosed in which a treatment zone is established around an energy source placed in a cavity within a coal seam and the pore structure of the coal substantially irreversibly collapses as moisture is driven off. The energy source provides either evaporative energy such as heat or a combination of heat and pressure in-situ. Resorption of water returning to the treatment zone during cooling of the coal prior to mining is limited due to the pore collapse.