Showing papers on "Energy source published in 1991"

TRENDS '90: A compendium of data on global change

Abstract: This document is a source of frequently used global change data. This first issue includes estimates for global and national CO{sub 2} emissions from the burning of fossil fuels and from the production of cement, historical and modern records of atmospheric CO{sub 2} and methane concentrations, and several long-term temperature records. Included are tabular and graphical presentations of the data, discussions of trends in the data, and references to publications that provide further information. Data are presented in a two-page format, each dealing with a different data set. All data are available in digital form from the Carbon Dioxide Information Analysis Center.

Fuel ethanol from cellulosic biomass.

Abstract: Ethanol produced from cellulosic biomass is examined as a large-scale transportation fuel. Desirable features include ethanol's fuel properties as well as benefits with respect to urban air quality, global climate change, balance of trade, and energy security. Energy balance, feedstock supply, and environmental impact considerations are not seen as significant barriers to the widespread use of fuel ethanol derived from cellulosic biomass. Conversion economics is the key obstacle to be overcome. In light of past progress and future prospects for research-driven improvements, a cost-competitive process appears possible in a decade.

Chemical composition of emissions from urban sources of fine organic aerosol

Abstract: A dilution source sampling system was used to collect primary fine aerosol emissions from important sources of urban organic aerosol, including a boiler burning No 2 fuel oil, a home fireplace, a fleet of catalyst-equipped and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat cooking operations Alternative dilution sampling techniques were used to collect emissions from cigarette smoking and a roofing tar pot, and grab sample techniques were employed to characterize paved road dust, brake lining wear, tire wear, and vegetative detritus Organic aerosol constituted the majority of the fine aerosol mass emitted from many of the sources tested Fine primary organic aerosol emissions within the heavily urbanized western portion of the Los Angeles Basin were determined to total 298 metric tons/day Over 40% of these organic aerosol emissions are from anthropogenic pollution sources that are expected to emit contemporary (nonfossil) aerosol carbon, in good agreement with the available ambient monitoring data

Generation and Migration of Petroleum from Abnormally Pressured Fluid Compartments: Reply

Abstract: Much of the world's oil and gas has been generated from source rocks inside deep (> 3,000 m or 9,840 ft) seal-bounded fluid compartments. The quantity and composition of the kerogen and the burial history of the source rocks determine the volumes of petroleum generated; however, the migration from the compartments in an oil and gas phase is a pressure-driven process in which the flow direction is controlled by the configuration and internal pressures of the fluid compartments. Many sedimentary basins contain layers of two or more superimposed hydrogeological systems. The shallow systems are usually basin wide in extent and exhibit normal hydrostatic pressures. The deeper systems, where the oil is generated, are not basin wide and are abnormally over pressured. They usu lly consist of a series of individual fluid compartments that are not in hydraulic pressure communication with each other nor with the overlying hydrodynamic regime. Tops of fluid compartments in currently sinking basins do not always follow a specific stratigraphic horizon. They frequently have planar tops and subsurface temperatures ranging from 90 degrees to 100 degrees C (194 degrees to 212 degrees F). The tops in clastic sediments appear to be caused by carbonate mineralization along a thermocline. In the North Sea, the depth to the top of the deepest seal changes with the geothermal gradient. The seal is deeper where the gradient is lower. The generation of oil and gas within the compartments plus the thermal expansion of pore fluids eventually causes fracturing of the top compartment seal during periods of basin sinking. Hydrocarbons and other pore fluids then move vertically into the overlying lower pressured sediments and accumulate in the nearest structural and stratigraphic traps. Seal fracturing causes a pressure drop with compartment fluids rushing to the breakout point. The compartment then re-seals and pressure builds to another breakout. This episodic process continues with resealing and breakout cycles probably occurring in intervals of thousands of years in rapidly sinking basins such as the United States Gulf Coast. This concept of episodic dewatering of deep-basin fluid compartments needs to be considered n any basin-modeling program where the bulk of the oil generation occurs in the compartmented overpressured section of the basin and the oil moves vertically into the normally pressured rocks above.

Passive Nondestructive Assay of Nuclear Materials

Abstract: The term nondestructive assay (NDA) is applied to a series of measurement techniques for nuclear fuel materials. The techniques measure radiation induced or emitted spontaneously from the nuclear material; the measurements are nondestructive in that they do not alter the physical or chemical state of the nuclear material. NDA techniques are characterized as passive or active depending on whether they measure radiation from the spontaneous decay of the nuclear material or radiation induced by an external source. This book emphasizes passive NDA techniques, although certain active techniques like gamma-ray absorption densitometry and x-ray fluorescence are discussed here because of their intimate relation to passive assay techniques. The principal NDA techniques are classified as gamma-ray assay, neutron assay, and calorimetry. Gamma-ray assay techniques are treated in Chapters 1--10. Neutron assay techniques are the subject of Chapters 11--17. Chapters 11--13 cover the origin of neutrons, neutron interactions, and neutron detectors. Chapters 14--17 cover the theory and applications of total and coincidence neutron counting. Chapter 18 deals with the assay of irradiated nuclear fuel, which uses both gamma-ray and neutron assay techniques. Chapter 19 covers perimeter monitoring, which uses gamma-ray and neutron detectors of high sensitivity to check that no unauthorized nuclear materialmore » crosses a facility boundary. The subject of Chapter 20 is attribute and semiquantitative measurements. The goal of these measurements is a rapid verification of the contents of nuclear material containers to assist physical inventory verifications. Waste and holdup measurements are also treated in this chapter. Chapters 21 and 22 cover calorimetry theory and application, and Chapter 23 is a brief application guide to illustrate which techniques can be used to solve certain measurement problems.« less

Reactivity of organic compounds in hot water: geochemical and technological implications.

Abstract: Understanding of the reactivity of organic molecules in hot water is developing from studies aimed at explaining how organic matter (kerogen) forms in natural environments and then breaks down into energy source materials. In natural systems where kerogens are depolymerized, hot water is ubiquitous and usually contains salt and minerals. Reactions such as ionic condensation, cleavage, and hydrolysis are facilitated by changes in the chemical and physical properties of water as temperature increases. These changes make the solvent properties of water at high temperature similar to those of polar organic solvents at room temperature, thus facilitating reactions with organic compounds. An understanding of aqueous organic chemistry may lead to potential applications in areas as diverse as the recycling of plastics, the synthesis of chemicals, and coal liquefaction.

Biodegradation of 2,4-dinitrotoluene by a Pseudomonas sp.

Abstract: Previous studies of the biodegradation of nonpolar nitroaromatic compounds have suggested that microorganisms can reduce the nitro groups but cannot cleave the aromatic ring. We report here the initial steps in a pathway for complete biodegradation of 2,4-dinitrotoluene (DNT) by a Pseudomonas sp. isolated from a four-member consortium enriched with DNT. The Pseudomonas sp. degraded DNT as the sole source of carbon and energy under aerobic conditions with stoichiometric release of nitrite. During induction of the enzymes required for growth on DNT, 4-methyl-5-nitrocatechol (MNC) accumulated transiently in the culture fluid when cells grown on acetate were transferred to medium containing DNT as the sole carbon and energy source. Conversion of DNT to MNC in the presence of 18O2 revealed the simultaneous incorporation of two atoms of molecular oxygen, which demonstrated that the reaction was catalyzed by a dioxygenase. Fully induced cells degraded MNC rapidly with stoichiometric release of nitrite. The results indicate an initial dioxygenase attack at the 4,5 position of DNT with the concomitant release of nitrite. Subsequent reactions lead to complete biodegradation and removal of the second nitro group as nitrite.

Role of plant biomass in the global environmental partitioning of chlorinated hydrocarbons

Abstract: Plant biomass plays a significant role in the global environmental partitioning phenomena and plants are good indicators of tropospheric contamination levels by chlorinated hydrocarbons. In the present research 300 samples of plants were collected in 265 areas distributed worldwide and analyzed for HCB (hexachlorobenzene), {alpha}-HCH (hexachlorocyclohexane), {gamma}-HCH, p,p{prime}-DDT,o,p{prime}-DDT, and p,p{prime}-DDE (degradation product of DDT). Global HCB distribution is strongly dependent on the temperature, the HCB being present mainly in samples from cold areas. The sum of DDTs show higher concentrations in samples from topical areas, while the sum of HCHs is higher in the plants from the Northern Hemisphere. These results are discussed, taking into account the role of physicochemical properties in determining the global distribution as well as the air age of the contamination.

Experimental and simulation study of high-temperature foam displacement in porous media

Abstract: This paper reports on high-temperature surfactant foams that are simulated by modifying gas-phase mobility in a conventional thermal simulator. Both surfactant-alternating-gas (SAG) and gas/liquid-coinjection processes are modeled. Foam generation by leave-behind and snap-off as well as foam coalescence and trapping mechanisms are incorporated in the model by an equation for the number density of foal bubbles; gas-phase relative permeability and apparent viscosity are modified according to the bubble density. Pressure and saturation data of laboratory corefloods are successfully history matched with simulation results. Field-scale sensitivity studies of the steam-foam-drive process demonstrate how the coalescence rate affects the extent of steam diversion.

Product toxicity and cometabolic competitive inhibition modeling of chloroform and trichloroethylene transformation by methanotrophic resting cells.

Abstract: The rate and capacity for chloroform (CF) and trichloroethylene (TCE) transformation by a mixed methanotrophic culture of resting cells (no exogenous energy source) and formate-fed cells were measured. As reported previously for TCE, formate addition resulted in an increased CF transformation rate (0.35 day-1 for resting cells and 1.5 day-1 for formate-fed cells) and transformation capacity (0.0065 mg of CF per mg of cells for resting cells and 0.015 mg of CF per mg of cells for formate-fed cells), suggesting that depletion of energy stores affects transformation behavior. The observed finite transformation capacity, even with an exogenous energy source, suggests that toxicity was also a factor. CF transformation capacity was significantly lower than that for TCE, suggesting a greater toxicity from CF transformation. The toxicity of CF, TCE, and their transformation products to whole cells was evaluated by comparing the formate oxidation activity of acetylene-treated cells to that of non-acetylene-treated cells with and without prior exposure to CF or TCE. Acetylene arrests the activity of methane monooxygenase in CF and TCE oxidation without halting cell activity toward formate. Significantly diminished formate oxidation by cells exposed to either CR or TCE without acetylene compared with that with acetylene suggests that the solvents themselves were not toxic under the experimental conditions but their transformation products were. The concurrent transformation of CF and TCE by resting cells was measured, and results were compared with predictions from a competitive-inhibition cometabolic transformation model. The reasonable fit between model predictions and experimental observations was supportive of model assumptions.

Effects of toxicity, aeration, and reductant supply on trichloroethylene transformation by a mixed methanotrophic culture

Abstract: The trichloroethylene (TCE) transformation rate and capacity of a mixed methanotrophic culture at room temperature were measured to determine the effects of time without methane (resting), use of an alternative energy source (formate), aeration, and toxicity of TCE and its transformation products. The initial specific TCE transformation rate of resting cells was 0.6 mg of TCE per mg of cells per day, and they had a finite TCE transformation capacity of 0.036 mg of TCE per mg of cells. Formate addition resulted in increased initial specific TCE transformation rates (2.1 mg/mg of cells per day) and elevated transformation capacity (0.073 mg of TCE per mg of cells). Significant declines in methane conversion rates following exposure to TCE were observed for both resting and formate-fed cells, suggesting toxic effects caused by TCE or its transformation products. TCE transformation and methane consumption rates of resting cells decreased with time much more rapidly when cells were shaken and aerated than when they remained dormant, suggesting that the transformation ability of methanotrophs is best preserved by storage under anoxic conditions.

Acidobacterium capsulatum gen. nov., sp. nov. : an acidophilic chemoorganotrophic bacterium containing menaquinone from acidic mineral environment

Abstract: Acidobacterium is proposed as a new genus for the acidophilic, chemoorganotrophic bacteria containing menaquinone isolated from acidic mineral environments.Acidobacterium capsulatum is proposed for the singleAcidobacterium species which consists of eight strains (Biogroup 5). The members of this species are gram-negative, aerobic, mesophilic, non-spore-forming, capsulated, saccharolytic, and rod-shaped bacteria. They are motile by peritrichous flagella. They can grow between pH 3.0 and 6.0, but not at pH 6.5. They give positive results in tests for esculin hydrolysis, catalase, and β-galactosidase. Oxidase and urease are negative. They can use glucose, cellobiose, starch, maltose, or β-gentiobiose as a sole carbon source, but cannot use elemental sulfur and ferrous iron as an energy source. The DNA base composition is 59.7–60.8 guanine plus cytosine (G+C) mol%. The major isoprenoid quinone is menaquinone with eight isoprene units (MK-8). The major fatty acid is 13-methyltetradecanoic acid. DNA relatedness between this species and the species ofAcidiphilium, Acidomonas, andDeinobacter was 18 to 2%. From phenotypic and chemotaxonomic characters, these member do not belong to any known taxa of gram-negative bacteria. A culture of the type strain (strain 161) has been deposited in the Japan Collection of Microorganisms as JCM 7670.

Multi-frequency two dimensional display system

Abstract: A digitized video system having a display including one or more multi-frequency sensitive materials and a spatial lighy modulator simultaneously directing a plurality individual beams from an energy source onto the display.

Behavioral and Physiological Characteristics of the Antarctic Krill, Euphausia superba

Abstract: The antarctic krill, Euphausia superba , is considered a success in the intensely seasonal environment of the Southern Ocean because of its abundance and central role as an important food item for many of the larger carnivores in the ecosystem. The behavioral and physiological characteristics that foster this success are: (1) the ability to find concentrations of food in several types of habitat and efficiently exploit whatever food is available; (2) the close correspondence of the life cycle with seasonal cycles of food availability; and (3) a combination of physiological mechanisms that enable krill to survive the long winter period of low food availability. We evaluated the relative importance of the following four major winter-over mechanisms that have been proposed for adult krill west of the Antarctic Peninsula. The three-fold reduction in metabolic rate is the most important winter-over mechanism for these adults, although lipid utilization and shrinkage also help satisfy energy requirements in the winter. Alternate food sources did not appear to contribute significantly as a winter energy source. However, the extent, predictability and complexity of the ice cover in a region during winter may have a great influence on the relative importance of these winter-over mechanisms for different populations. Ice cover in the waters west of the Antarctic Peninsula is unpredictable and smooth surfaced when it occurs, providing the krill with little refuge from predation. In multi-year pack ice of the Weddell Sea, however, ice cover is predictable and extensive, and there is a complex undersurface that provides hiding places. In this multi-year ice, adult krill have been observed under the ice feeding, whereas west of the Antarctic Peninsula most adult krill are in the water column in the winter and are not feeding. The balance between acquiring energy and avoiding predation may be different in these two regions in the winter because of differences in predictability and complexity of the ice cover.

Tropospheric nitrogen: A three‐dimensional study of sources, distributions, and deposition

Abstract: We simulate the global cycle of reactive nitrogen in a three-dimensional model of chemistry, transport, and deposition. Our model is based on the Lagrangian tracer model described by Walton et al. [1988] and uses winds and precipitation fields calculated by the Livermore version of the NCAR Community Climate Model. The model includes the basic chemical reactions of NO, NO2, and HNO3. For this study, we use prescribed OH and O3 concentrations and calculate the concentrations of NO, NO2, and HNO3 for a perpetual January and a perpetual July. The sources of reactive nitrogen due to fossil-fuel combustion (22 Mt N/yr), lightning discharges (3 Mt N/yr), soil microbial activity (10 Mt N/yr), biomass burning (6 Mt N/yr), and the oxidation of N2O in the stratosphere (1 Mt N/yr) are included. Model-predicted concentrations of NO, NO2, and HNO3 are compared to available measurements. In general, we find reasonable agreement between model predictions and measurements except for concentrations of HNO3 in the remote Pacific. At these latter locations, we require a larger source of reactive nitrogen to fit the observations. This may be supplied by lightning discharges, although increasing this source degrades our agreement with measured HNO3 abundances in the free troposphere. Alternatively, a local marine source could contribute to the measured abundances. Predictions for nitrate deposition by precipitation are within a factor of 2 of measured deposition rates in the northern hemisphere in the summer and in both seasons at remote locations. The model underpredicts nitrate deposition in winter in Europe, due primarily to the excessively strong winds generated by the general circulation model. Model simulations for NOx and HNO3 surface mixing ratios from calculations including only the fossil-fuel source, only natural sources, and all sources acting together, are compared. Anthropogenic sources have substantially increased the concentrations of NOx and HNO3 throughout all continents during both January and July. Fossil-fuel sources are responsible for most of this increase in the northern hemisphere, while both biomass burning and fossil-fuel combustion contribute in the southern hemisphere.

Partitioning of aromatic constituents into water from gasoline and other complex solvent mixtures

Abstract: Variations in gasoline composition (source variations) as well as complexity (nonideal behavior, cosolvent effects) contributing to variability in gasoline-water partitioning of aromatic hydrocarbon constituents were examined. Aromatic hydrocarbon concentrations in water extracts of 31 gasoline samples varied over 1 order of magnitude, reflecting the diversity in gasoline composition. However, the gasoline-water partition coefficients (K{sub fw}) varied by less than 30% among these samples. Partitioning between water and known mixtures of aromatic and aliphatic solvents was measured and used to estimate the upper and lower bounds of K{sub fw} values for more complex solvent mixtures such as gasoline and diesel fuel. Oxygenated additives, such as methanol and methyl tert-butyl ether (MTBE), were shown to have minimal cosolvent effects on hydrocarbon partitioning. The observed inverse, log-log linear dependence of K{sub fw} values on aqueous solubility could be well predicted by assuming gasoline to be an ideal solvent mixture (i.e., Raoult's law is valid).

Method and device for recanalization of a body passageway

Abstract: The present invention relates to a method and device for the recanalization of an occluded blood vessel which includes an expandable wire-mesh stent or support and an external radio frequency (rf) energy source or other suitable heat generating device. The device of the present invention may also be used to recanalize other occluded body passageways or conduits.

Toluene-4-monooxygenase, a three-component enzyme system that catalyzes the oxidation of toluene to p-cresol in Pseudomonas mendocina KR1.

Abstract: Pseudomonas mendocina KR1 grows on toluene as a sole carbon and energy source. A multicomponent oxygenase was partially purified from toluene-grown cells and separated into three protein components. The reconstituted enzyme system, in the presence of NADH and Fe2+, oxidized toluene to p-cresol as the first detectable product. Experiments with p-deutero-toluene led to the isolation of p-cresol which retained 68% of the deuterium initially present in the parent molecule. When the reconstituted enzyme system was incubated with toluene in the presence of 18O2, the oxygen in p-cresol was shown to be derived from molecular oxygen. The results demonstrate that P. mendocina KR1 initiates degradation of toluene by a multicomponent enzyme system which has been designated toluene-4-monooxygenase.

Thermal plasma processing

Abstract: A review is given of the fundamental aspects involved in material processing using thermal plasma technology. The description of plasma generating devices covers DC plasma torches, DC transferred arcs, RF inductively coupled plasma torches and hybrid combinations of them. Emphasis is given to the identification of the basic energy coupling mechanism in each case and the principal characteristics of the flow and temperature fields in the plasma. Materials processing techniques using thermal plasmas are grouped in two broad categories depending on the role played by the plasma in the process. Only typical examples are given of each type of process. These are grouped under two broad subsections dealing respectively with applications in which the plasma is used as a source of heat in high temperatures, and those in which the plasma is used as a source of chemically active species. The author also deals with plasma diagnostics and mathematical modeling and the role which they can play in the long term development of the technology. >

Population and the energy problem.

Abstract: When energy is scarce or expensive, people can suffer material deprivation and economic hardship. When it is obtained in ways that fail to minimize environmental and political costs, these too can threaten human wellbeing in fundamental and pervasive ways. The energy problem today combines these syndromes: much of the world's population has too little energy to meet basic human needs; the monetary costs of energy are rising nearly everywhere; the environmental impacts of energy supply are growing and already dominant contributors to local, regional, and global environmental problems (including air pollution, water pollution, ocean pollution, and climate change); and the sociopolitical risks of energy supply (above all the danger of conflict over oil and the links between nuclear energy and nuclear weapons) are growing too. This predicament has many causes, but predominant among them are the nearly 20-fold increase in world energy use since 1850 and the cumulative depletion of the most convenient oil and gas deposits that this growth has entailed, resulting in increasing resort to costlier and/or environmentally more disruptive energy sources. The growth of world population in this period was responsible for 52% of the energy growth, while growth in per capita energy use was responsible for 48% (excluding causal connections between population and energy use per capita). In the United States in the same period, population growth accounted for 66% of the 36-fold increase in energy use. In the late 1980s, population growth was still accounting for a third of energy growth both in the United States and worldwide. Coping with global energy problems will require greatly increased investment in improving the efficiency of energy enduse and in reducing the environmental impacts of contemporary energy technologies, and it will require financing a transition over the next several decades to a set of more sustainable (but probably also more expensive) energy sources. The difficulty of implementing these measures will be greatest by far in the developing countries, not least because of their high rates of population growth and the attendant extra pressures on economic and managerial resources. If efficiency improvements permit delivering the high standard of living to which the world aspires based on a per capita rate of energy use as low as 3 kilowatts—about a quarter of the current U.S. figure—then a world population stabilized at 10 billion people would be using energy at a rate of 30 terawatts, and a population of 14 billion would imply 42 terawatts (compare 13.2 terawatts in 1990). Delivering even the lower figure at tolerable monetary and environmental costs will be difficult; each additional billion people added to the world population will compound these difficulties and increase energy's costs, making everyone poorer.

Physiology of yeasts in relation to biomass yields.

Abstract: The stoichiometric limit to the biomass yield (maximal assimilation of the carbon source) is determined by the amount of CO2 lost in anabolism and the amount of carbon source required for generation of NADPH. This stoichiometric limit may be reached when yeasts utilize formate as an additional energy source. Factors affecting the biomass yield on single substrates are discussed under the following headings: Energy requirement for biomass formation (YATP). YATP depends strongly on the nature of the carbon source. Cell composition. The macroscopic composition of the biomass, and in particular the protein content, has a considerable effect on the ATP requirement for biomass formation. Hence, determination of for instance the protein content of biomass is relevant in studies on bioenergetics. Transport of the carbon source. Active (i.e. energy-requiring) transport, which occurs for a number of sugars and polyols, may contribute significantly to the calculated theoretical ATP requirement for biomass formation. P/O-ratio. The efficiency of mitochondrial energy generation has a strong effect on the cell yield. The P/O-ratio is determined to a major extent by the number of proton-translocating sites in the mitochondrial respiratory chain. Maintenance and environmental factors. Factors such as osmotic stress, heavy metals, oxygen and carbon dioxide pressures, temperature and pH affect the yield of yeasts. Various mechanisms may be involved, often affecting the maintenance energy requirement. Metabolites such as ethanol and weak acids. Ethanol increases the permeability of the plasma membrane, whereas weak acids can act as proton conductors. Energy content of the growth substrate. It has often been attempted in the literature to predict the biomass yield by correlating the energy content of the carbon source (represented by the degree of reduction) to the biomass yield or the percentage assimilation of the carbon source. An analysis of biomass yields of Candida utilis on a large number of carbon sources indicates that the biomass yield is mainly determined by the biochemical pathways leading to biomass formation, rather than by the energy content of the substrate.

Genetic classification of petroleum systems

Abstract: Our genetic classification of petroleum systems is founded on a simple working nomenclature that consists of combining qualifiers from each of the following three categories: (1) charge factor (supercharged, normally charged, or undercharged), (2) migration drainage style (vertically drained or laterally drained), and (3) entrapment style (high impedance or low impedance). The charge factor is estimated on the basis of the richness and volumetrics of mature source rocks. The source potential index (SPI), which combines source-rock richness and thickness into a single parameter, is a convenient shortcut for comparing the petroleum potential of diverse source rocks containing dissimilar kerogen types and for rapidly estimating regional charging capacity. In extensively explored basins, a positive correlation exists between the magnitude of SPI and basin-wide petroleum reserves. The migration drainage style is determined from the structural and stratigraphic framework of a basin. Vertical-migration drainage, which occurs mainly through faults and fracture systems breaching a seal, is characteristic of petroleum systems contained within rift basins, deltaic sequences, salt-dome provinces, wrench basins, and fold-and-thrust belts. In contrast, lateral-migration drainage is dominant wherever stratigraphically continuous seal-reservoir "doublets" extend over a very large area in a tectonically stable province (e.g., commonly foreland or intracratonic platform basins). Recognition of the dominant migration style helps to predict the location of zones of petroleum occurrence in relation to the "hydrocarbon kitchens." The entrapment style, which is also dependent on the structural framework and the presence and effectiveness of seals, describes the degree of resistance (i.e., impedance) working against dispersion of the petroleum charge. Application of these working concepts should help to significantly reduce geologic risk, particularly in new ventures-type exploration.