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Taller de Trabajo: Evaluacion de Impactos de Cambios Climaticos Globales sobre el Sistema Agricola Venezolano

Description: This report discusses the Assessment of Impacts of Global Climatic Changes on the Venezuelan Agricultural System Workshop, as part of the PAN-EARTH Project, Venezuela case study.
Date: September 1991
Creator: Acevedo, Miguel F.; Andressen, Rigoberto; Calderon, Carlos; Capacho, Liliana; Bisbal, Evelyn; Hanes, Rexene et al.
Partner: UNT College of Engineering

A Study of Reactor Systems for the Production of Tritium and Radioactive Cobalt

Description: "A conceptual design study of reactors for the join production of tritium and colbat-60 has been made. The study covered a family of four reactors raging in thermal power from 16.5 MW to 150 MW, and designed for corresponding annual productions ranging from 0.5 to 5.0 million curies of tritium respectively."--P. v.
Date: June 8, 1959
Partner: UNT Libraries Government Documents Department

Experimental factors affecting PCR-based estimates of microbial species richness and evenness

Description: Pyrosequencing of 16S rRNA gene amplicons for microbial community profiling can, for equivalent costs, yield greater than two orders of magnitude more sensitivity than traditional PCR-cloning and Sanger sequencing. With this increased sensitivity and the ability to analyze multiple samples in parallel, it has become possible to evaluate several technical aspects of PCRbased community structure profiling methods. We tested the effect of amplicon length and primer pair on estimates of species richness number of species and evenness relative abundance of species by assessing the potentially tractable microbial community residing in the termite hindgut. Two regions of the 16S rRNA gene were sequenced from one of two common priming sites, spanning the V1-V2 or V8 regions, using amplicons ranging n length from 352 to 1443 bp. Our results demonstrate that both amplicon length and primer pair markedly influence estimates of richness and evenness. However, estimates of species evenness are consistent among different primer pairs targeting the same region. These results highlight the importance of experimental methodology when comparing diversity estimates across communities.
Date: December 1, 2009
Creator: Engelbrektson, Anna; Kunin, Victor; Wrighton, Kelly C.; Zvenigorodsky, Natasha; Chen, Feng; Ochman, Howard et al.
Partner: UNT Libraries Government Documents Department

U.S. Regional Agricultural Production in 2030 and 2095: Response to CO2 Fertilization and Hadley Climate Model (HadCM2) Projections of Greenhouse-Forced Climatic Change

Description: Research activities underway to evaluate potential consequences of climate change and variability on the agriculture, water resources, and other U.S. sectors were mandated by the Global Change Research Act of 1990. These activities are being carried out in a public-private partnership under the guidance of the U.S. Global Change Research Program. Researchers at Pacific Northwest National Laboratory (PNNL) have been using integrated assessment methodologies to appraise the possible impacts of global warming and climatic variability on the behavior of managed and natural systems. This interim PNNL report contributes to the U.S. National Assessment process with an analysis of the modeled impacts of climatic changes projected by the Hadley/UKMO (HadCM2) general circulation model on agricultural productivity and selected environmental variables. The construction of climatic data for the simulation runs followed general guidelines established by the U.S. National Assessment Synthesis Team. The baseline climate data were obtained from national records for the period 1961 - 1990. The scenario runs for two future periods (2025 - 2030 and 2090 - 2099) were extracted from results of a HadCM2 run distributed at a half-degree spatial resolution. The Erosion Productivity Impact Calculator (EPIC) was used to simulate the behavior of 204 "representative farms" (i.e., soil-climate-management combinations) under baseline climate, the two future periods and their combinations with two levels of atmospheric C02 concentrations (365 and 560 ppm). Analysis of simulation results identified areas in Texas, New Mexico, Colorado, Utah, Arizona, and California that would experience large temperature increases by 2030. Slight cooling is expected by 2030 in parts of Alabama, Florida, Maine, Montana, Idaho, and Utah. Larger areas will experience increased warming by 2095. Uniform precipitation increases are expected by 2030 in the north eastern quarter of the country. These uniform precipitation increases are expected to expand to the eastern half of the country by ...
Date: November 19, 1999
Creator: Rosenberg, NJ & Brown, RC Izaurralde: RA
Partner: UNT Libraries Government Documents Department

Farm Practices That Increase Crop Yields in Kentucky and Tennessee

Description: "In the limestone and mountain districts south of the Ohio River there is much land that has been run down by continual cropping without rotation. In some places run-down land is left to grow up in weeds, wild grasses, and brush, a practice known as 'resting' the land. Where this sort of farm management is followed farm manure is largely wasted, little or no attention is paid to green-manure crops or other means of putting humus into the soil, and crop yields are very low. However, progressive farmers throughout the region who have built up run-down lands are now getting heavy yields. In the following pages are described some of the methods by which these farmers get results by making good use of farm manure and crop refuse, using legumes and grasses in regular rotations, and applying lime and commercial fertilizers." -- p. 2
Date: 1918
Creator: Arnold, J. H. (Jacob Hiram), 1864-1921
Partner: UNT Libraries Government Documents Department

Crop Systems for Arkansas

Description: "Crop systems for Arkansas that make for increased food production and increased efficiency in man labor and horse labor are described in the following pages. By the introduction of cowpeas, soybeans, and other legumes, and by second cropping, provision is made for a considerable increase in the number of crop acres that can be farmed by the average family.... In each of the cropping systems suggested the crop acreages are calculated for two men and a team, and for light, medium, and heavy soils. These systems in general apply to all of Arkansas, except the northwestern part, and some of them may be used to advantage in northern Louisiana, northeastern Texas, southeastern Oklahoma, western Tennessee, and the northern half of Mississippi." -- p. 2
Date: 1918
Creator: McNair, A. D.
Partner: UNT Libraries Government Documents Department

The Farm Tractor in the Dakotas

Description: This bulletin explains how gas-driven tractors can increase the productivity of farms in North and South Dakota and uses data in order to convince farmers that a farm tractor is a worthwhile investment. It also discusses issues with tractors such as maintenance and repairs and operating costs.
Date: unknown
Creator: Yerkes, Arnold P. & Church, L. M.
Partner: UNT Libraries Government Documents Department

REDUCING ULTRA-CLEAN TRANSPORTATION FUEL COSTS WITH HYMELT HYDROGEN

Description: This report describes activities for the sixth quarter of work performed under this agreement. MEFOS conducted a third round of atmospheric testing as scheduled on December 9 through December 12, 2003. We reported experimental activities of this testing last quarter. We report process calculations and results this quarter. The test results demonstrated a much-improved rate of carbon dissolution with gas yields close to thermodynamic equilibrium at nearly doubled feed rates of September testing and a commercially viable feed and oxygen injection technique. Additional super-atmospheric testing to perform the last task in the MEFOS experimental program is scheduled for the last quarter of 2004.
Date: April 1, 2004
Creator: Malone, Donald P. & Renner, William R.
Partner: UNT Libraries Government Documents Department

REDUCING ULTRA-CLEAN TRANSPORTATION FUEL COSTS WITH HYMELT HYDROGEN

Description: This report describes activities for the fifth quarter of work performed under this agreement. A third round of atmospheric testing was conducted as scheduled on December 9 through December 12, 2003. The test results demonstrated a much-improved rate of carbon dissolution with gas yields close to thermodynamic equilibrium at nearly doubled feed rates of September testing and a commercially viable feed and oxygen injection technique. Additional super-atmospheric testing to perform the last task in the MEFOS experimental program is scheduled for the week of August 2004.
Date: January 1, 2003
Creator: Malone, Donald P. & Renner, William R.
Partner: UNT Libraries Government Documents Department

Green Manuring

Description: "Green manuring means turning under suitable crops to enrich the soil. Such crops may be turned under green or when ripe. Green manuring adds organic matter and, directly or indirectly, nitrogen to the soil. Leguminous crops are most desirable for green manuring, since they add to the soil nitrogen gathered from the air in addition to the organic matter which they carry. Besides the nitrogen in the legumes turned under, an additional supply of nitrogen is fixed in the soil by the action of bacteria, using the carbon in the organic matter as a source of energy. Turning under an entire crop is advised only when the soil is poor and for the purpose of starting a rotation. Turning under catch crops or winter-grown green crops is an economical and successful method of supplying nitrogen." -- p. 2
Date: 1922
Creator: Piper, Charles V. (Charles Vancouver), 1867-1926 & Pieters, A. J.
Partner: UNT Libraries Government Documents Department

REDUCING ULTRA-CLEAN TRANSPORTATION FUEL COSTS WITH HYMELT HYDROGEN

Description: This report describes activities for the fourth quarter of work performed under this agreement. A second round of atmospheric testing was conducted as scheduled on September 2 through September 4, 2003. The test results demonstrated a much-improved rate of carbon dissolution with gas yields close to expectations. Additional atmospheric testing to demonstrate a commercially feasible feed and oxygen injection method is scheduled for the week of December 8, 2003.
Date: October 31, 2003
Creator: Malone, Donald P. & Renner, William R.
Partner: UNT Libraries Government Documents Department

The Economic Value of PV and Net Metering to Residential Customers in California

Description: In this paper, we analyze the bill savings from PV for residential customers of the California's two largest electric utilities, under existing net metering tariffs as well as under several alternative compensation mechanisms. We find that economic value of PV to the customer is dependent on the structure of the underlying retail electricity rate and can vary quite significantly from one customer to another. In addition, we find that the value of the bill savings from PV generally declines with PV penetration level, as increased PV generation tends to offset lower-priced usage. Customers in our sample from both utilities are significantly better off with net metering than with a feed-in tariff where all PV generation is compensated at long-run avoided generation supply costs. Other compensation schemeswhich allow customers to displace their consumption with PV generation within each hour or each month, and are also based on the avoided costs, yield similar value to the customer as net metering.
Date: May 17, 2010
Creator: Darghouth, Naim; Barbose, Galen & Wiser, Ryan
Partner: UNT Libraries Government Documents Department

Methane coupling by membrane reactor. Quarterly technical progress report, September 25, 1995--December 24, 1995

Description: The performance of the third type of catalytic membrane reactor configuration, with catalyst deposited in the membrane and no catalyst or inert materials in the tube side, was evaluated. The C{sub 2} selectivity obtained was about 10% due to the gas phase reaction in the empty tube side of the reactor. The membrane reactor with an oxygen-permeable dense membrane has been built. The use of a dense membrane will eliminate the loss of hydrocarbon from the tube side to the shell side, as observed in the Vycor glass membrane reactor. Also, air can be used as the oxygen source without contaminating the product. La/MgO was synthesized and will be used as the catalyst for the dense membrane reactor. This catalyst was reported in the literature to show significant improvement of C{sub 2} selectivity and yield for oxidative coupling of methane in a packed-bed reactor by using the operation mode of staged-feed of oxygen. A reactor mode for methane oxidative coupling in reactors with both distributed oxygen feed and C{sub 2} product removal was developed based on the general model of cross-flow reactors reported in the last quarterly report. A distributed oxygen feed could give rise to much higher C{sub 2} yield than the co-feed reactor as long as the space time is long enough. In the case of a two-membrane reactor, where oxygen is supplied by one membrane and products are removed through the other membrane, a high separation factor of C{sub 2} product to methane for the product-removal membrane is critical to achieve high C{sub 2} yield.
Date: March 15, 1996
Partner: UNT Libraries Government Documents Department

The US/UK Actinides Experiment at the Dounreay PFR

Description: The United States and the United Kingdom have been engaged in a joint research program in which samples of higher actinides were irradiated in the 600-MW Dounreay Prototype Fast Reactor in Scotland. Analytical results using mass spectrometry and radiometry for actinides and fission products are now available for the samples in Fuel Pins 1 and 2, which were irradiated for 63 full-power days, and for the samples in Fuel Pin 4, which were irradiated for 492 full-power days. Results from these three fuel pins are providing estimates of integral cross sections and fission yields.
Date: November 1, 1997
Creator: Raman, S., Walker, R.L., Dickens, J.K., Murphy, B.D.
Partner: UNT Libraries Government Documents Department

Electron emission following the interaction of slow highly charged ions with solids

Description: The interaction of highly-charged ions with surfaces involves many excitation processes of the surface atoms and the bulk material. One such process, the emission of electrons from surfaces due to the potential energy of the incident ions has been studied. The experimental results presented here confirm that the majority of electrons emitted as a result of highly-charged ions interacting with a solid surface have energies of about 20 eV. Auger processes contribute a smaller fraction of the total emitted electrons with increasing Z of the projectile. This contribution to the total electron emission yield is found to be less than 5% for Ne{sup 9+} and less than 1% for Ar{sup 18+}. For Z{>=} 54, no Auger electrons were detected. The early indications that the total number of emitted low energy electrons increases linearly with charge have been demonstrated not to hold for q {>=} 18.
Date: January 1, 1998
Creator: McDonald, J.W., LLNL
Partner: UNT Libraries Government Documents Department

Reduced yield detonation characteristics in large failure diameter materials

Description: We have made detailed measurements of the approach to steady, self-supported propagating shock waves at greatly reduced yield in composite propellants. Propa- gation velocities are less than one half the theoretical value expected for full reac- tion at the sonic plane. Previous experimental studies 1 have given evidence of similar behavior. Also, previous theoretical work 2 in an analytic form has shown the possibility of reduced yield detonations. We have developed a reaction model coupled with a hydrody- namic code that together provide a description of the coupling of the complex reac- tion behavior with shock propagation and expansion in energetic materials. The model results show clearly that if the dependence of reaction rate on pressure is of sufficiently low order and the mode of consumption is by "grain burning" the calcu- lated detonation behavior closely parallels the observed non-ideal results. We describe the experiments, the reaction model, and compare experimental and calculational results. We also extend the model to predict results in the unexplored regime of very large size charges.
Date: August 10, 1998
Creator: Lambert, R R; Lee, E L; Maienschein, J L; Merill, C I; Nichols, III & Reaugh, J E
Partner: UNT Libraries Government Documents Department