724 research outputs found
The Economic Feasibility of Using Georgia Biomass for Electrical Energy Production
This study investigates the potential for using biomass for the production of electricity in Georgia. The volume, important characteristics, and delivered costs per unit of energy are estimated for various locally produced biomass. Production of synthetic fuels using both pyrolysis and gasification technologies is investigated as potential means for converting biomass into electricity. Capital and operating costs for each of these two technologies are projected across three different scales of production. Estimated costs per unit of electricity generated are determined. It appears, under the conditions modeled, these technologies are not cost competitive with currently used technologies. Significant subsidies would be needed to induce the adoption of these technologies under current economic conditions.bio-electricity, bio-feedstocks, biomass, cost, electricity, Agribusiness, Resource /Energy Economics and Policy,
Economic Impacts of Ethanol Production in Georgia
Capital costs to construct a conventional ethanol plant producing 100 million gallons per year are 59.216 million with a 1% chance of annual net returns less than 314.221 million in the Georgia economy. Wages and benefits total 4.572 million in tax revenues from ethanol production.Resource /Energy Economics and Policy,
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Characterization of the chemical signatures of air masses observed during the PEM experiments over the western Pacific
Extensive observations of tropospheric trace species during the second NASA Global Tropospheric Experiment Western Pacific Exploratory Mission (PEM-West B) in February-March 1994 showed significant seasonal variability in comparison with the first mission (PEM-West A), conducted in September-October 1991. In this study we adopt a previously established analytical method, i.e., the ratio C2H2/CO as a measure of the relative degree of atmospheric processing, to elucidate the key similarities and variations between the two missions. In addition, the C2H2/CO ratio scheme is combined with the back-trajectory-based and the LIDAR-based air mass classification schemes, respectively, to make in-depth analysis of the seasonal variation between PEM-West A and PEM-West B (hereinafter referred to as PEM-WA and PEM-WB). A large number of compounds, including long-lived NMHCs, CH4, and CO2, are, as expected, well correlated with the ratio C2H2/CO. In comparison with PEM-WA, a significantly larger range of observed C2H2/CO values at the high end for the PEM-WB period indicates that the western Pacific was more impacted by "fresher" source emissions, i.e., faster or more efficient continental outflow. As in the case of PEM-WA, the C2H2/CO scheme complements the back-trajectory air mass classification scheme very well. By combining the two schemes, we found that the atmospheric processing in the region is dominated by atmospheric mixing for the trace species analyzed. This PEM-WB wintertime result is similar to that found in PEM-WA for the autumn. In both cases, photochemical reactions are found to play a significant role in determining the background mixing ratios of trace gases, and in this way the two processes are directly related and dependent upon each other. This analysis also indicates that many of the upper tropospheric air masses encountered over the western Pacific during PEM-WB may have had little impact from eastern Asia's continental surface sources. NOx mixing ratios were significantly enhanced during PEM-WB when compared with PEM-WA, in the upper troposphere's more atmospherically processed air masses. These high levels of NOx resulted in a substantial amount of photochemical production of O3. A lack of corresponding enhancements in surface emission tracers strongly implies that in situ atmospheric sources such as lightning are responsible for the enhanced upper tropospheric NOx. The similarity in NOx values between the northern (higher air traffic) and southern continental air masses together with the indications of a large seasonal shift suggests that aircraft emissions are not the dominant source. However, photochemical recycling cannot be ruled out as this in situ source of NOx. Copyright 1999 by the American Geophysical Union
Quantum Mechanics and Linearized Gravitational Waves
The interaction of classical gravitational waves (GW) with matter is studied
within a quantum mechanical framework. The classical equations of motion in the
long wave-length limit is quantized and a Schroedinger equation for the
interaction of GW with matter is proposed. Due to its quadrapole nature, the GW
interacts with matter by producing squeezed quantum states. The resultant
hamiltonian is quite different from one would expect from general principles,
however. The interaction of GW with the free particle, the harmonic oscillator
and the hydrogen atom is then studied using this hamiltonian.Comment: 24 pages, written in REVTE
Place attachment in deprived neighbourhoods: The impacts of population turnover and social mix
This paper examines the determinants of individual place attachment, focussing in particular on differences between deprived and others neighbourhoods, and on the impacts of population turnover and social mix. It uses a multi-level modelling approach to take account of both individual- and neighbourhood-level determinants. Data are drawn from a large sample government survey, the Citizenship Survey 2005, to which a variety of neighbourhood-level data have been attached. The paper argues that attachment is significantly lower in more deprived neighbourhoods primarily because these areas have weaker social cohesion but that, in other respects, the drivers of attachment are the same. Turnover has modest direct impacts on attachment through its effect on social cohesion. Social mix has very limited impacts on attachment and the effects vary between social groups. In general, higher status or more dominant groups appear less tolerant of social mix
Random and Correlated Phases of Primordial Gravitaional Waves
The phases of primordial gravity waves is analysed in detail within a quantum
mechanical context following the formalism developed by Grishchuk and Sidorov.
It is found that for physically relevant wavelengths both the phase of each
individual mode and the phase {\it difference} between modes are randomly
distributed. The phase {\it sum} between modes with oppositely directed
wave-vectors, however, is not random and takes on a definite value with no rms
fluctuation. The conventional point of view that primordial gravity waves
appear after inflation as a classical, random stochastic background is also
addressed.Comment: 14 pages, written in REVTE
The consequences of perceived age discrimination amongst older police officers : is social support a buffer ?
This paper considers the possible psychological consequences of perceived agediscrimination, and the possible buffering effect of social support. Findings, based on a studyof perceived age discrimination amongst police officers in the North of England, suggest thatage discrimination acts as a stressor, with officers experiencing negative effects of perceivedage discrimination on job and life satisfaction, perceived power and prestige of the job, andaffective and normative commitment, along with positive effects on withdrawal cognitionsand continuance commitment. For work-based social support, there were positive maineffects on job and satisfaction, power and prestige of the job, and affective and normativecommitment, and a negative main effect on withdrawal cognitions. However, there were nosignificant moderating effects for work-based social support, and we found the anticipatedbuffering effect for non-work-based social support only for life satisfaction, with reversebuffering for job satisfaction and normative commitment. The limitations and implications ofthe study are discussed
A Prospective Program to Reduce the Clinical Incidence of Clostridium Difficile Colitis Infection after Cystectomy
Purpose
The development of Clostridium difficile infection after cystectomy is associated with significant morbidity and mortality. We implemented a prospective screening program to identify asymptomatic carriers of Clostridium difficile and assessed its impact on clinical Clostridium difficile infection rates compared to historical matched controls.
Materials and Methods
Prospective Clostridium Difficile screening prior to cystectomy began in March 2015. The 380 consecutive patients undergoing cystectomy prior to initiation of screening (control cohort) were matched based on 5 clinical factors with the 386 patients who underwent cystectomy from March 2015 to December 2017 (trial cohort). Screened positive patients were placed in contact isolation and treated prophylactically with Metronidazole. Multivariable models were built on an intention-to-screen and an effectiveness of screening basis to determine if screening reduced the rates of symptomatic Clostridium Difficile infections postoperatively.
Results
With the implementation of the screening protocol, Clostridium difficile infections rates declined from 9.4 to 5.5% (OR 0.52, p=0.0268) on an intention-to-screen protocol and from 9.2 to 4.9% on an effectiveness of screening protocol (OR 0.46, p=0.0174).
Conclusions
Clostridium difficile screening prior to cystectomy is associated with a significant decrease in rates of clinically symptomatic infections postoperatively. These results should be confirmed in a randomized controlled trial
Did tool-use evolve with enhanced physical cognitive abilities?
The use and manufacture of tools have been considered to be cognitively demanding and thus a possible driving factor in the evolution of intelligence. In this study, we tested the hypothesis that enhanced physical cognitive abilities evolved in conjunction with the use of tools, by comparing the performance of naturally tool-using and non-tool-using species in a suite of physical and general learning tasks. We predicted that the habitually tool-using species, New Caledonian crows and Galápagos woodpecker finches, should outperform their non-tool-using relatives, the small tree finches and the carrion crows in a physical problem but not in general learning tasks. We only found a divergence in the predicted direction for corvids. That only one of our comparisons supports the predictions under this hypothesis might be attributable to different complexities of tool-use in the two tool-using species. A critical evaluation is offered of the conceptual and methodological problems inherent in comparative studies on tool-related cognitive abilities
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Evaluation of the Transient Hydrologic Source Term for the Cambric Underground Nuclear Test at Frenchman Flat, Nevada test Site
The objective of Phase II HST work is to develop a better understanding of the evolution of the HST for 1,000 years at the CAMBRIC underground nuclear test site in Frenchman Flat at the NTS. This work provides a better understanding of activities as they actually occurred, incorporates improvements based on recent data acquisition, and provides a basis to use the CAMBRIC site for model validation and monitoring activities as required by the UGTA Project. CAMBRIC was the only test in Frenchman Flat detonated under the water table and best represents a fully saturated environment. These simulations are part of a broad Phase II Frenchman Flat Corrective Action Unit (CAU) flow and transport modeling effort being conducted by the Department of Energy (DOE) Underground Test Area (UGTA) Project. HST simulations provide, either directly or indirectly, the source term used in the CAU model to calculate a contaminant boundary. Work described in this report augments Phase I HST calculations at CAMBRIC conducted by Tompson et al. (1999) and Pawloski et al. (2001). Phase II HST calculations have been organized to calculate source terms under two scenarios: (1) A representation of the transient flow and radionuclide release behavior at the CAMBRIC site that is more specific than Tompson et al. (1999). This model reflects the influence of the background hydraulic gradient, residual test heat, pumping experiment, and ditch recharge, and takes into account improved data sources and modeling approaches developed since the previous efforts. Collectively, this approach will be referred to as the transient CAMBRIC source term. This report describes the development of the transient CAMBRIC HST. (2) A generic release model made under steady-state flow conditions, in the absence of any transient effects, at the same site with the same radiologic source term. This model is for use in the development of simpler release models for the other nine underground test sites in the Frenchman Flat CAU. This approach will be referred to as the steady-state (non-transient) CAMBRIC source term. This work is described in a separate report (Tompson et al., 2005)
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