bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Consumption Analysis of Residential Central Air Conditioning Systems
Authors: Wei Bing , Yang Huayi
Published: October 2010

Nowadays the energy crisis has been more and more severe all over the world. In China there is enormous energy source, but due to the large number of population, the average possession of the total energy is lower, and the energy supply is relatively less. Enormous energy consumption of air conditioning systems in the residential buildings makes the energy conservation more important. The residential central air conditioning systems are being widely used due to its advantages of easy control and low operating cost. But there are still many problems to be resolved, of which the energy consumption of the residential central air-conditioning systems is a hot issue. The main cold and heat sources for residential central air conditioning systems are air-cooled heat pump unit, household gas air conditioning unit, air-cooled chiller unit/gas-fired boiler and water loop heat pump unit. The terminal facilities suited for the anterior three units are the fan coil units, and the terminal of the last water loop heat pump unit is normally indoor unit. The combined utilization of the heat and cold source units with their terminal units keep the indoor environment in desired state all the year. In this paper, based on an actual example, the basic principles of four systems mentioned above are outlined and analyzed, and four schemes are compared. By using the method of equivalent weight full load operation time, the annual energy consumptions of the four schemes are calculated and analyzed. Comparing the annual primary energy consumption of four schemes, the following conclusions can be drawn: in the case studied, the energy consumption of the household gas-fired air conditioning unit with fan coil system is the maximum, the consumption of the air-cooled chiller unit/gas-fired boiler with fan coil system is the next, then is the air-cooled heat pump with fan coil system, and that of the water loop heat pump system is the minimum. It can be observed that the water loop heat pump system is the optimal one and is the best on energy conservation. Through the study of this paper, the minimum energy consumption system is chosen so as to give the references for the energy savings of air-conditioning systems in the practice.
The Design and Rating of the Pressure Exchange Steam Ejector for a Waste Heat Driven Automotive Air Conditioning System
Authors: Gould David M. , Garris Charles A.
Published: October 2010

A pressure exchange ejector invented by George Washington University’s Professor Charles Garris has been considered a novel concept for energy conversion and utilization of two working fluids. One of the applications of the pressure exchange ejector involves taking the captured waste heat from the car’s engine to assist in running its air conditioning system. This study involves implementing the pressure exchange ejector in a modified vapor compression air conditioning system and determining its feasibility with performance and sizing for a typical midsize sedan. The specific midsize sedan chosen in the analysis is the inline six-cylinder BMW 530i sedan. The analysis involves comparing previous results and data of high and low cooling loads from the conventional automotive air conditioning (A/C) system using R-134a refrigerant with a new steam pressure exchange ejector A/C system. The pressure exchange (PE) ejector similar to the conventional ejector can be represented by the turbomachinery analog. Desirable theoretically efficiencies of the PE ejector using the turbomachinery analog are varied to determine the minimal efficiency required to run the ejector air conditioning system. The performances of the ideal and minimum condition for the PE ejector A/C system are determined to view the potential and feasibility of the system. The system consists of environmentally friendly steam as a refrigerant and replaces the conventional A/C system’s engine driven compressor with an ejector and a second loop for waste heat recovery from the car’s engine exhaust system. Simulation tests of varying ejector efficiency under the designed A/C system and vehicle conditions are conducted through computational heat transfer and thermodynamic analysis using MATLAB/Simulink. The software is a numerical calculation and visualization software program where various environmental, thermodynamic, heat transfer, and sizing conditions can be monitored. Engine exhaust heat and conventional air conditioning results and properties are obtained through previous experiments and analysis at respected universities and laboratories.
Simulation of a Volumetric Solar Receiver-Reactor for Hydrogen Producing Thermochemical Cycles
Authors: Noglik Adam , Roeb Martin , Sattler Christian , Pitz-Paal Robert
Published: October 2010

Sulfur based thermochemical cycles for hydrogen generation from water have one reaction step in common which is the decomposition of sulfuric acid as one of the most energy consuming steps. The present work deals with the development of a dynamic mathematical model of a solar reactor for this key step. One of the core parts of the model is a part model of the reaction kinetics of the decomposition of sulfur trioxide, which is based on experiments investigating the kinetics of the used catalyst platinum coated on a ceramic solar absorber. Other part models describe e. g. the absorption of solar radiation, heat conduction in the absorber, convection between gas and the absorber walls and energy losses due to heat radiation. A comprehensive validation of the reactor model is performed using measured data which is gained in experiments with a prototype reactor. The operating behavior of the real reactor is compared with the results of the numerical simulation with the model. The validation is in particular done by reproducing the influences of individual parameters on the chemical conversion and the reactor efficiency. The relative deviations between experimental data and simulation results are mostly within the range of measurement accuracy. In particular the good agreement of calculated values of the derived parameters SO3 conversion and reactor efficiency with those determined from the experiments qualify the model for optimization purposes.
Economics Analysis of Sewage Source Heat Pump System
Authors: Wei Bing , Zhang Bin , Jiang Lu , Luo Wen
Published: October 2010

To sewage treatment plants, the sewage is plenteous and costless. If the sewage is utilized for air conditioning purpose, it will achieve more value. The temperature of sewage is basically constant in summer or winter. The treated sewage can be used for absorbing the condensing heat in summer and releasing heat to the building space in winter through the sewage heat exchanger. Especially the heating coefficient of the sewage source heat bump is higher in winter, which is an advantage to heating. In this paper the cooling and heating theory of the sewage source heat bump is briefly introduced, the advantages and disadvantages of sewage source heat bump system is explained. With an example in Beijing, China, compared with the boiler/ductless split air conditioner system, the initial investment and annual operating cost are calculated and the economics of the sewage source heat pump system is analyzed. At last the impact of fossil fuel rate and electric rate on the annual operating costs is analyzed. The calculating results showed that under the present rates of fossil fuel and electricity in China, the initial investment of the sewage source heat pump system is higher, the annual operating cost is lower than that of the boiler/ductless split air conditioner system. All these above will be good references for the actual applications of sewage source heat pump systems.
Economic Potential of Solar Thermal Power Plants With Direct Steam Generation Compared to HTF Plants
Authors: Feldhoff Jan Fabian , Benitez Daniel , Eck Markus , Riffelmann Klaus-Ju¨rgen
Published: October 2010

The direct steam generation (DSG) in parabolic trough collectors is a promising option to improve the mature parabolic trough solar thermal power plant technology of the Solar Energy Generating Systems (SEGS) in California. According to previous studies [1–3], the cost reduction of the DSG process compared to the SEGS technology is expected to be 8 to 25%. All these studies were more or less preliminary since they lacked detailed information on the design of collector fields, absorber tubes required for steam temperatures higher than 400°C and power blocks adapted to the specific needs of the direct steam generation. To bridge this gap, a detailed system analysis was performed within the German R&D project DIVA. Power blocks and collector fields were designed for four different capacities (5, 10, 50 and 100 MWel) and different live steam parameters. The live steam temperature was varied between saturation temperature and 500°C, and live steam pressures of 40, 64 and 100 bar were investigated. To assess the different cases, detailed yield analyses of the overall system were performed using hourly data for the direct normal irradiation and the ambient temperature for typical years. Based on these results the levelized costs of electricity were determined for all cases and compared to a reference system using synthetic oil as heat transfer fluid (HTF). This paper focuses on two main project findings. First, the 50 MWel DSG system parameter comparisons are presented. Second, the detailed comparison between a DSG and a SEGS-like 100 MWel system is given. The main result of the investigation is that the benefit of the DSG process depends on the project site and can reach an 11% reduction of the levelized electricity cost (LEC).
Evaluation of a High-Performance Multifamily Residential Building in Aspen, Colorado
Authors: Hendron Robert , Hancock Ed , Barker Greg , McDowell Tim
Published: October 2010

Multifamily housing is an essential component of urban sustainable design, because finite available urban space necessitates greater use of attached housing and shared community spaces. Improving the energy efficiency of this category of housing presents special challenges, because units share walls and the space heating and domestic hot water systems are frequently centralized, requiring recirculation and long pipe runs to reach all units. These challenges were investigated as part of the first phase of a high-performance multifamily housing community called Burlingame Ranch in Aspen, Colorado. The first phase of the project has been completed, and features such energy efficiency measures as insulated slab-on-grade foundations, condensing boilers, solar preheat for hot water, heat recovery ventilation, and energy-efficient lighting and appliances. The authors participated in a thorough evaluation of key building systems for one prototype building and provided insights into potential design improvements that can be implemented in the second phase of construction.
New Solar Air Heater Based on Non-Imaging Optics for High-Temperature Applications
Authors: Rinco´n E. , Dura´n M. , Lentz A.
Published: October 2010

A novel solar air heater is presented, that allows for temperatures exceeding 100° C with thermal efficiencies of over 50%, due to a non-imaging solar concentrator and the reduction of thermal losses from the air circulating between the absorber and mirrors with a circular cross-section, which are well insulated from the outside surroundings. The receiver consists of a concentrator with transparent prisms that function as lenses. The rays of light refracted by the prisms enter a series of CPC concentrators, which have been optimally truncated so that the space between them allows for the positioning of the absorber, which consists of a series of metallic segments covered with a selective film. Its excellent performance makes it ideal for applications such as Sauna baths, drying processes at high temperatures, and air conditioning systems.
EcoEagles Hybrid Vehicle Control Architecture
Authors: Stansbury Richard S. , Towhidnejad Massood , White Darris , McKisson Jack
Published: October 2010

The EcoCar Challenge provides 17 universities the opportunity to compete in the design and development of a new hybrid-vehicle based off of the 2009 Saturn Vue. At Embry-Riddle Aeronautical University, the vehicle’s initial architecture has been designed that provides the opportunity for the vehicle to operate in up to four different modes: electric only, series, parallel thru the road, and gas only. The control architecture is comprised of the various embedded controllers throughout the vehicle plus the addition of two new computer systems. The first is a safety critical supervisory controller responsible for configuring the vehicle into one of the hybrid modes. The second is the Intelligent Drive Efficiency Assistant (I.D.E.A), which is responsible for suggesting the best hybrid mode possible given the anticipated state of the vehicle. This paper will present the control architecture and the hardware/software-in-the-loop test bed necessary to verify and evaluate the architecture as it is developed.
Mimo Generalized Predictive Control for a Small Wind Turbine–Fuel Cell Hybrid Energy System
Authors: Valencia Guillermo E. , Cubas Glen Gabriel , Turizo John C. , Chamorro Ramiro J.
Published: October 2010

This paper presents a comparative performance analysis between the generalized predictive control (GPC) and the traditional proportional integral derivative (PID) under different dynamics cases in hybrid energy systems, which is composed of by a 400 W small wind turbine, a polymer electrolyte membrane (PEM) fuel cells (PEMFC), an electrolyzer, and finally the ultracapacitors and a power converter unit in order to minimize voltage fluctuations in the system and generate AC voltage. In addition, the transient responses of the system to step changes in the load current and wind speed are presented as a result of the manipulation in the flow of reactants to the fuel cell. SIMULINK™ is used for the simulation of this highly nonlinear hybrid energy system.
Hydrogen Economy or Electricity Economy?: A Transportation Case Study
Authors: Evans Robert L.
Published: October 2010

Transportation accounts for more than a quarter of total global energy consumption. For fuelling road transportation there has been much speculation about the use of hydrogen as an energy carrier, which proponents claim would usher in the “Hydrogen Economy”. The concept of the “complete energy conversion chain” has been used to compare the overall energy consumption and CO2 emissions from vehicles powered by hydrogen fuel cells with those from vehicles using a battery and electric drive. The analysis shows that if a sustainable source of electricity is used to produce hydrogen, then the hydrogen and fuel cell system is just equivalent to a battery. The efficiency of these two different approaches has been compared, and shows that the hydrogen system would consume nearly three times the primary energy required by a battery storage system. Conventional batteries do not, however, have a sufficiently high energy storage density to provide the range needed for most drivers. A new generation of plug-in hybrid vehicles is being developed which take advantage of the best attributes of both electric vehicles and conventional fossilfuelled vehicles. These vehicles show promise to dramatically reduce the quantity of greenhouse gases produced each year by the transportation sector.
Fresnel Lens Soiling Characterization and Effect Upon Performance
Authors: Banchik Leonardo D. , Sahm Aaron , Boehm Robert , Stone Kenneth W.
Published: October 2010

The Amonix system is a high concentration PV system that utilizes acrylic Fresnel lenses to focus the sun’s rays onto dispersed PV cells. The Fresnel lenses become soiled with dust over time which decreases power performance. Because of the effect soiling has upon the system performance, Amonix and the University of Nevada, Las Vegas (UNLV) have defined a long term soiling investigation and cleaning methodology. The test and measurement procedure for determining Fresnel lens soiling rate characterization is discussed. Lens soiling rate data is presented for different sites that show the soiling rate is a direct function of the angle of the lens. This paper also discusses the test and measurement procedure of the first phase of an on-going Fresnel lens cleaning investigation. An assessment of the soiling rate upon power production is also presented.
Design and Model Based Performance Analysis of a District Energy Supply System
Authors: Hu Yang , Archer David H. , Yin Hongxi
Published: October 2010

A district energy supply system for Almono, Pittsburgh has been studied by the Center for Building Performance and Diagnostics, Carnegie Mellon University. Almono is a mixed residential/commercial redevelopment proposed for a 178 acre brown field site on the banks of the Monongahela River in Pittsburgh, PA. The district energy supply system would provide electric power, cooling, and heating for the occupants and the buildings of the site and for possible additional energy based developments. The various energy requirements of Almono’s proposed residential and commercial buildings for power, cooling, heating, and hot water have been estimated first based on Energy Information Administration data (1993), and then again on the advanced building code of the International Energy Conservation Code 2006 (IECC 2006). A comparison of these estimates highlights the importance of building envelopes on the energy requirements of the Almono development. The daily and seasonal load profiles for power, cooling, and heating that challenge efficient and economic operation of district energy supply have been developed. Various prime mover technologies for combined cooling/heating/power, CCHP, systems have been considered: gas turbine, internal combustion engine, and steam turbine. These technologies affect the choice of fuel, and the fractions of power and heat provided. The paper estimates loads of the Almono site based on the operation and performance of both conventional and advanced residential and commercial office buildings, suggests additional energy loads that would provide for improved technical and economic performance of system, and considers the selection of a fuel and the use of solar energy as the energy sources. It presents preliminary overall flow diagrams for various district energy supplies that include various possible fuel and solar energy inputs, and use of the river as a heat source/sink. It also comments on operation of the district energy supply to meet the hourly and seasonal energy loads of the Almono site.
Algaculture as a Feedstock Source for Biodiesel Fuel: A Life Cycle Analysis
Authors: Curtiss Peter S. , Kreider Jan F.
Published: October 2010

This research investigates algae as a feedstock for producing liquid fuels for the light vehicle sector. It is in the interest of national economic security to investigate alternative sources of transportation energy before the extraction of existing supplies becomes prohibitively expensive. Biofuels are one such alternative liquid fuel supply. The research used the Life Cycle Analysis (LCA) approach for evaluating the production of biodiesel fuel from algae as a feedstock, including processes for growing algae in conventional and accelerated processes in bioreactors. An energy return on investment and comparison with conventional fuels (gasoline, diesel fuel) on an LCA basis and on a resource consumption basis (e.g., land, water, feedstock) is also presented. The results are reported for required land use, water use, input-to-output energy ratio, and carbon emissions for algacultural biodiesel fuel. From the present study it appears that algae-derived biodiesel fuel requires significantly less land, water and energy than do all other biodiesel fuels. It would appear prudent for the US to vigorously pursue this option since a significant fraction of US light vehicle fuel needs can be addressed.
Supercritical CO2 as a Heat Transfer and Power Cycle Fluid for CSP Systems
Authors: Glatzmaier Greg C. , Turchi Craig S.
Published: October 2010

Concentrating Solar Power (CSP) utilizes solar thermal energy to drive a thermal power cycle for the generation of electricity. CSP technologies include parabolic trough, linear Fresnel, central receiver or “power tower,” and dish/engine systems. The parabolic trough is the most common system with nine Solar Electric Generating Stations (SEGS) operating in southern California for over two decades and new plants online in Nevada and Spain. The resurgent interest in CSP has been driven by renewable portfolio standards in southwestern states and renewable energy feed-in tariffs in Spain. CSP has cost advantages versus solar photovoltaic systems for large, centralized power plants. Certain CSP systems, in particular parabolic troughs and power towers, are also amenable to the incorporation of thermal energy storage. Thermal energy storage is much less expensive than electric storage and allows CSP plants to increase capacity factor and dispatch power as needed — for example, to cover an evening demand peak.
Experimental Validation of a Simplified PEMFC Simulation Model
Authors: Martins Lauber S. , Ordonez Juan C. , Vargas Jose V. C.
Published: October 2010

In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained with the model for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, and current increase that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes.
Thermodynamic and Economic Optimization of a MCFC Power Generation Unit Coupled With Hydrogen Production
Authors: Nicolin Flavio , Verda Vittorio
Published: October 2010

In this paper, a biogas fuelled power generation system is considered. The system is based on a molten carbonate fuel cell (MCFC) stack integrated with a micro gas turbine for electricity generation, coupled with a pressure swing absorption system (PSA) for hydrogen production. The aim of this work is the optimal design of the system plant considering thermodynamic and economic objective functions. The procedure starts from system decomposition in two parts: the heat transfer network and the other components (in the following indicated as the “power components”). Design parameters are the pressure ratio, some operating temperatures and mass flow rates. For each set of the design parameters, the corresponding thermodynamic conditions of flows entering and exiting the power components are obtained. Then the heat flux recovered in the heat transfer network and the primary energy consumption are determined. Economic analysis is performed by considering function costs for the power components and a relation between the heat transfer network cost and the main energy requirements. The latter is obtained through analysis of a few heat transfer network configurations.
Performance Predictions of a Circulation Controlled-Vertical Axis Wind Turbine With Solidity Control
Authors: Wilhelm Jay P. , Pertl Emily D. , Pertl Franz A. , Smith James E.
Published: October 2010

Conventional straight bladed vertical axis wind turbines are typically designed to produce maximum power at tip speed ratio, but power production can suffer when operating outside of the design range. These turbines, unless designed specifically for low speed operation, may require rotational startup assistance. Circulation control methods, such as using blowing slots on the trailing edge could be applied to a Vertical Axis Wind Turbine (VAWT) blade. Improvements to the amount of power developed at lower speeds and elimination or reduction of startup assistance could be possible with this lift augmentation. Selection of a beneficial rotor solidity and control over when to utilize the blowing slots for the CC-VAWT (Circulation Controlled-Vertical Axis Wind Turbine) appears to have a profound impact on overall performance. Preliminary performance predictions indicate that at a greater range of rotor solidities, the CC-VAWT can have overall performance levels that exceed a conventional VAWT. This paper describes the performance predictions and solidity selection of a circulation controlled vertical axis wind turbine that can operate at higher overall capture efficiencies than a conventional VAWT.
In-Situ Polymerized Wicks for Passive Water Management in PEM Fuel Cell Systems
Authors: Strickland Daniel G. , Fenning David , Litster Shawn , Santiago Juan G.
Published: October 2010

Air delivery is the largest parasitic power loss in typical PEM fuel cell systems. Integrated wicks for water management can help minimize this loss by enabling low stoichiometric airflow rate operation in parallel channel (low pressure drop) flow field architectures. In this work, we develop a novel water management wick design and fabrication procedure. This in-situ polymerized wick design is adaptable to existing state-of-the-art separator plates; and can be integrated into a wide variety of flow field structures (including stamped stainless steel or injection molded plates).
Porous Metal Hydride (PMH) Compacts for Thermal Energy Applications
Authors: Lee Michael , Park Il-Seok , Kim Sunwoo , Kim Kwang J.
Published: October 2010

Pelletized Porous Metal Hydride (PMH) was investigated in order to assess its thermal capability for energy storage/transfer applications. Metal hydrides have been known as promising materials for hydrogen storage systems, heat storage systems, and thermal devices, thanks to their nearly reversible reaction characteristics during the hydrogen absorbing and desorbing processes. The conventional powder-type metal hydrides however have a relatively low thermal conductivity, which is responsible for low heat generation. In the present study three representative metal hydrides, LaNi5, Ca0.6Mm0.4Ni5, and LaNi4.75Al0.25, metal hydride powders were coated with thin copper and pressed at 3,000 psig with metal additives in order to improve the thermal conductivity. This pelletizing process does not require the use of an organic binder and additional processes such as sintering under high pressure. The pelletized PMH compacts employing the copper coating exhibit higher thermal conductivity compared to raw metal hydride powders. However, pelletizing may deteriorate the permeability of the PMH compacts, lowering mass transfer of hydrogen. Therefore, the permeability must be observed to verify whether it meets the required level for suitable applications. Measurements were performed by varying copper fractions and plotted against the upstream/downstream pressure differential. Darcy’s equation in conjunction with an ideal gas assumption was used to calculate the permeability of a rigid wall design. This investigation reveals that rising copper content is accompanied with decreases in permeability. Permeability values for most samples tested in this study were found to be larger than the desirable level, 5 × 10−15 m2. Additionally, the thermal performance of the LaNi5 PMH compacts was tested by calculating and comparing the heat generation of the PMH pellets and powders filled reactors during the hydrogen absorption process in water bath medium.
Economic Analysis of a 3 MW Biomass Gasification Power Plant
Authors: Cattolica Robert , Herz Richard , Giolitto James , Summers Matt
Published: October 2010

An economic and technical analysis of the use of separated wood biomass as a feedstock for gasification for a 3 MW power plant was conducted for the Miramar Landfill, located in San Diego County, CA. The method to generate combustible gas from the biomass is based on a dual-fluidized bed gasification process which operates at atmospheric pressure with air and produces a high quality producer gas with little nitrogen. The objective of the study was to determine the economic feasibility of the proposed biomass power system in terms of the potential revenue streams and costs. Major economic considerations in the analysis include feedstock, capital, and operating costs. Regulatory issues, inclusive of production credits, renewable energy incentives, and feed-in tariffs are addressed as significant economic inputs. The Miramar landfill, in San Diego County, CA is representative of a typical existing urban landfill, with corresponding feedstock and some market for separated wood biomass. The economic analysis of the proposed 3MW gasification power plant indicates that it would not have a net positive NPV under the current urban scenario. More likely successful candidates are landfill sites in more rural areas or urban sites, where new landfills are being developed or where the landfill is no longer operational but has become a transfer station. In all cases waste heat sales are a critical element in determining economic viability.
A Hybrid Ventilation System in Carnegie Mellon’s Intelligent Workplace
Authors: Marion Flore A. , Aslanian Elisabeth , Durandeux Sophie V. , Archer David H.
Published: October 2010

An analytical and experimental study of hybrid ventilation is being carried out by Carnegie Mellon’s Center for Building Performance and Diagnostics in its Intelligent Workplace, the IW. Hybrid ventilation in this space will be carried out either operating a mechanical system, a SEMCO rev2250 desiccant wheel unit that distributes outside air conditioned, to a set temperature and humidity or alternatively opening windows when outdoor and indoor conditions are favorable, turning off the ventilation and the space cooling units. This hybrid ventilation approach will maintain a healthy, comfortable, and pleasant environment for the occupants of the IW and also will reduce the operating costs for the ventilation and cooling of the space. The key factor to the successful performance of a hybrid ventilation system is its operating procedures, the logical algorithms for opening and closing windows based on measurements of outdoor and indoor conditions: temperatures, humidity, wind velocity, rain, occupancy, etc. Algorithms have been proposed for operating the windows in the IW’s hybrid ventilation system. These algorithms have been programmed in a Trnsys model of IW with its windows and its mechanical ventilation and cooling units. This model has been exercised for an operating period including the spring, summer, and fall seasons in Pittsburgh to establish how much time the windows remain open and what savings in operating energy for the IW’s mechanical ventilation and cooling system are achieved. This modeling study evaluates the benefits of a hybrid ventilation system compared to a base case where mechanical ventilation is used. About 8% of the ventilation and cooling energy is saved. At this time a hybrid ventilation system, its hardware equipment and software controls, has been installed in the IW. Measurements are being made to establish that healthy, comfortable conditions are maintained in the IW and that model estimates of energy savings are confirmed. In future work, guides lines will be written to inform building professionals, architects and engineers, about hybrid ventilation and its benefits in the design of buildings across the United States.
A Comparison of Focus and Effectiveness of European Versus U.S. Energy Efficiency Programs for Buildings
Authors: Reichard Georg , Bhattacharjee Suchismita
Published: October 2010

The authors present a comparative study on effectiveness of energy policies for the building sector that are presently implemented in selected countries in Europe versus selected states in the U.S. Socio-economic factors affecting energy consumption on both sides of the Atlantic are identified from a human behavior perspective. Various identified factors known to affect energy efficiency and consumption have been positioned in diagrams based on four primary directions: lifestyle, economy, environment, and technology. In a second step various programs and incentives are positioned in the same diagram to demonstrate how well these strategies address the factors identified before. This is done for selected countries and continents in sub-diagrams to allow a comparison of effectiveness and provide a tool for predicting the effectiveness of a possible policy or program transfer to other nations. The research conducted so far suggests that energy efficiency policies and measures implemented in the United States do not always target the factors that have been identified to most significantly influence energy consumption. The results indicate that there might be a significant gap between parameters that are guiding factors affecting energy consumption, and parameters targeting a proper implementation of energy efficient policies. The authors strive to provide a tool that will help policy makers and other decision makers to evaluate and compare their incentives and programs against those from other countries and benefit from lessons learned by mapping various policies towards specific efficiency parameters.
Cumulative Exergy and Life Cycle Assessment of Ethanol Fuel Production From Corn via Dry Milling
Authors: Rajvanshi Noorie , Ingley Herbert A.
Published: October 2010

This study represents a cumulative exergy and life cycle assessment of corn ethanol production via dry milling. The process under consideration includes the agricultural process for production of corn, transportation of corn and industrial process of ethanol production. The secondary process of production of pesticides and fertilizers is also taken into consideration. It is seen that the exergy content of ethanol produced from this process is 23.3 MJ per liter of ethanol produced. The non-renewable input was 7.5 MJ per liter. The overall production efficiency of the industrial process was found to be 49%. The life cycle assessment results showed that both the global warming potential and acidification potential are positive which means that the production of corn ethanol via dry milling contributes to the increase of greenhouse gases and acidification.
Analysis of Web-Based Solar Photovoltaic Mapping Tools
Authors: Dean Jesse , Kandt Alicen , Burman Kari , Lisell Lars , Helm Christopher
Published: October 2010

As the demand for renewable energy has grown, so too has the need to quantify the potential for these resources. Understanding the potential for a particular energy source can help inform policy decisions, educate consumers, drive technological development, increase manufacturing capacity, and improve marketing methods. In response to the desire to better understand the potential of clean energy technologies, several approaches have been developed to help inform decisions. One technology-specific example is the use of solar photovoltaic (PV) maps. A solar PV mapping tool visually represents a specific site and calculates PV system size and projected electricity production. This paper identifies the commercially available solar mapping tools and provides a thorough summary of the source data type and resolution, the visualization software program being used, user inputs, calculation methodology and algorithms, map outputs, and development costs for each map.
eSolar’s Modular Concentrating Solar Power Tower Plant and Construction of the Sierra Solar Generating Station
Authors: Pacheco James E.
Published: October 2010

eSolar has developed a cost-effective, utility-scale solar power tower plant that uses mass-manufactured components which are designed for modularity, rapid deployment and construction, and are easily scalable. eSolar’s design for a full commercial power tower plant consists of 16 receiver-heliostat field modules that generate superheated steam to power a 46 MWe turbine. Each receiver-heliostat field module comprises a north and south rectangular-shaped subfield that reflects concentrated sunlight onto a receiver located between the subfields. The receiver absorbs the concentrated sunlight in a dual cavity. It is a natural-circulation boiler consisting of economizer, evaporator, and superheater panels. A steam drum separates the saturated steam, which is superheated in the superheater panels of the receiver. The steam flows to a turbine generator to produce electricity. After passing through the turbine, the steam is condensed and returns to the cycle. Heat from the condenser is rejected by a wet cooling tower. eSolar is constructing the Sierra Solar Generating Station in Lancaster, California to demonstrate its technology. This power tower plant consists of two full-scale receiver-heliostat fields that can produce 5 MWe. This project will demonstrate the full functionality of two receiver-heliostat field modules coupled with a small Rankine-cycle turbine.
B Cell Receptor Togetherness
Authors: Ray L. Bryan
Published: October 2010

Activation of the B cell receptor appears to require release of the receptors from an autoinhibited, oligomeric state.
Channel STIMulation
Authors: Ray L. Bryan
Published: October 2010

The sensor protein that monitors depletion of intracellular calcium regulates two classes of calcium entry channels.
Science Signaling
Podcast: 5 October 2010
Authors: Hermann Dirk M. , VanHook Annalisa M.
Published: October 2010

Inhibition of apolipoprotein E signaling is a potential clinical strategy for enhancing the delivery of neuroprotective drugs to the brain after ischemic stroke.
Photolysis of Hydrogen Peroxide, an Effective Disinfection System via Hydroxyl Radical Formation
Authors: Ikai Hiroyo , Nakamura Keisuke , Shirato Midori , Kanno Taro , Iwasawa Atsuo , Sasaki Keiichi , Niwano Yoshimi , Kohno Masahiro
Published: October 2010

The relationship between the amount of hydroxyl radicals generated by photolysis of H
2
O
2
and bactericidal activity was examined. H
2
O
2
(1 M) was irradiated with laser light at a wavelength of 405 nm to generate hydroxyl radicals. Electron spin resonance spin trapping analysis showed that the amount of hydroxyl radicals produced increased with the irradiation time. Four species of pathogenic oral bacteria,
Staphylococcus aureus
,
Aggregatibacter actinomycetemcomitans
,
Streptococcus mutans
, and
Enterococcus faecalis
, were used in the bactericidal assay.
S
.
mutans
in a model biofilm was also examined. Laser irradiation of suspensions in 1 M H
2
O
2
resulted in a >99.99% reduction of the viable counts of each of the test species within 3 min of treatment. Treatment of
S
.
mutans
in a biofilm resulted in a >99.999% reduction of viable counts within 3 min. Other results demonstrated that the bactericidal activity was dependent on the amount of hydroxyl radicals generated. Treatment of bacteria with 200 to 300 μM hydroxyl radicals would result in reductions of viable counts of >99.99%.
Tigecycline Population Pharmacokinetics in Patients with Community- or Hospital-Acquired Pneumonia
Authors: Rubino Christopher M. , Forrest Alan , Bhavnani Sujata M. , Dukart Gary , Cooper Angel , Korth-Bradley Joan , Ambrose Paul G.
Published: October 2010

Tigecycline is a new-generation of tetracycline (glycylcyclines) and is active
in vitro
against bacteria that possess any of the classical genes that confer tetracycline resistance through ribosomal protection or efflux pumps. Herein, tigecycline disposition in patients with community- or hospital-acquired pneumonia was described using a population pharmacokinetic model. Additionally, the influence of covariates, such as body surface area, severity of illness, and clinical laboratory measures, on tigecycline disposition was evaluated. An intravenous loading dose of 100 mg was followed by 50 mg of tigecycline every 12 h. The final population pharmacokinetic model was a two-compartment model with linear elimination and with a relationship between tigecycline clearance and body surface area and creatinine clearance. The model was parameterized using total clearance (CL), the volume of the central compartment, distributional clearance from the central to the peripheral compartment, and volumes of distribution at steady state. Relationships between body surface area and creatinine clearance were identified as significant predictors of interindividual variability on CL. This model will serve as the basis for estimating tigecycline exposure for pharmacokinetic-pharmacodynamic analyses for efficacy and safety among patients with community- or hospital-acquired pneumonia.
Increased Pho Regulon Activation Correlates with Decreased Virulence of an Avian Pathogenic
Escherichia coli
O78 Strain
Authors: Bertrand Nicolas , Houle Sébastien , LeBihan Guillaume , Poirier Édith , Dozois Charles M. , Harel Josée
Published: October 2010

Avian pathogenic
Escherichia coli
(APEC) strains are associated with respiratory infections, septicemia, cellulitis, peritonitis, and other conditions, since colibacillosis manifests in many ways. The Pho regulon is jointly controlled by the two-component regulatory system PhoBR and by the phosphate-specific transport (Pst) system. To determine the specific roles of the PhoBR regulon and the Pst system in the pathogenesis of the APEC O78 strain χ7122, different
phoBR
and
pst
mutant strains were tested
in vivo
in chickens and
in vitro
for virulence traits. Mutations resulting in constitutive activation of the Pho regulon rendered strains more sensitive than the wild type to hydrogen peroxide and to the bactericidal effects of rabbit serum. In addition, production of type 1 fimbriae was also impaired in these strains. Using a chicken competitive infection model, all PhoB constitutive mutants were outcompeted by the wild-type parent, including strains containing a functional Pst system. Cumulative inactivation of the Pst system and the PhoB regulator resulted in a restoration of virulence. In addition, loss of the PhoB regulator alone did not affect virulence in the chicken infection model. Interestingly, the level of attenuation of the mutant strains correlated directly with the level of activation of the Pho regulon. Overall, results indicate that activation of the Pho regulon rather than phosphate transport by the Pst system plays a major role in the attenuation of the APEC O78 strain χ7122.
Role of Adrenomedullin in Lyme Disease
Authors: Marre Meghan L. , Darcy Courtney T. , Yinh Janeth , Akira Shizuo , Uematsu Satoshi , Steere Allen C. , Hu Linden T.
Published: October 2010

Borrelia burgdorferistimulates a strong inflammatory response during infection of a mammalian host. To understand the mechanisms of immune regulation employed by the host to control this inflammatory response, we focused our studies on adrenomedullin, a peptide produced in response to bacterial stimuli that exhibits antimicrobial activity and regulates inflammatory responses by modulating the expression of inflammatory cytokines. Specifically, we investigated the effect ofB. burgdorferion the expression of adrenomedullin as well as the ability of adrenomedullin to dampen host inflammatory responses to the spirochete. The concentration of adrenomedullin in the synovial fluid of untreated Lyme arthritis patients was elevated compared with that in control osteoarthritis patient samples. In addition, coculture withB. burgdorferisignificantly increased the expression of adrenomedullin in RAW264.7 macrophages through MyD88-, phosphatidylinositol 3-kinase (PI3-K)-, and p38-dependent signaling cascades. Furthermore, the addition of exogenous adrenomedullin toB. burgdorferi-stimulated RAW264.7 macrophages resulted in a significant decrease in the induction of proinflammatory cytokines. Taken together, these results suggest thatB. burgdorferiincreases the production of adrenomedullin, which in turn negatively regulates theB. burgdorferi-stimulated inflammatory response.
Metal complexes of an amine bisphenol with a thiophene side-arm
Authors: Salminen Eero , Sillanpää Reijo , Lehtonen Ari
Published: October 2010

Dioxomolybdenum(VI) and oxotungsten(VI) complexes with a new amine bisphenol ligand (H2L) are reported. The ligand which carries a neutral nitrogen atom, two phenolic oxygen atoms and a thiophene side-arm was synthesized by a simple one-pot Mannich reaction. Further reaction with [MoO2(acac)2] yielded a monomeric molybdenum complex [MoO2(L)(MeOH)] (2a) or a dimeric complex [Mo2O2(μ-O)2(L)2] (2b), depending on the reaction conditions. The reaction with a tungsten trisglycolate [W(eg)3] led to the formation of a monomeric compound [WO(eg)(L)] (3). In these complexes, the potentially tetradentate amine bisphenolate dianion coordinates as a tridentate O,N,O donor while the sulfur side-arm donor remains intact. The solid-state structure of 2a was investigated by X-ray crystallography.
Use of far field basilar artery stenting for recurrent middle cerebral artery ischemia
Authors: Titsworth W Lee , Civelek A Cahid , Abou-Chebl Alex
Published: October 2010

Intracranial artery angioplasty and stenting are generally performed for ipsi-territory stroke prevention in stenotic disease; however, few options exist for chronic occlusion of a proximal feeding vessel. In such circumstances intracranial angioplasty and stenting of a neighboring vascular field may improve collateral flow to the territory of the occluded vessel. A case of basilar artery (BA) stenting is presented, performed to improve collateral flow in a man experiencing recurrent middle cerebral artery (MCA) strokes, despite superior temporal artery (STA)–MCA bypass for internal carotid artery occlusion. Following BA stenting, the patient had complete cessation of MCA ischemia and improved cerebrovascular reserve by single photon emission CT. BA stenting was found to be a safe and effective means of improving collateral flow to mitigate recurrent MCA infarctions. Far field interventions should be considered in selected patients who fail other treatments.
‘Dippers' flu’ and its relationship to PON1 polymorphisms
Authors: Cherry Nicola , Mackness Michael , Mackness Bharti , Dippnall Martin , Povey Andrew
Published: October 2010

Objectives

Sheep-dippers report an acute flu-like condition (dippers' flu: DF) but the cause and relation to chronic disability are unknown.

Methods

In a case-referent study previously reported, 175 sheep dippers with chronic disability and 234 referents, sheep dippers in good health, completed an interview with information on dipping, type of pesticide used and health for each year 1970–2000 and gave blood for typing of PON1 polymorphisms.

Results

Reports of DF were much higher (66.3% 116/175) in the chronically unwell than in those without chronic ill-health (18.0% 42/234: OR=8.99 95% CI 5.69–14.21). No significant relation was seen between reported exposures and DF in those with chronic illness, but risk was higher with concentrate handling in those without. An R allele at position 192 on PON1 related to reports of DF both in those with chronic illness (OR=2.04 95% CI 1.08–3.87) and in those who started dipping after 1969 and were not chronically unwell (OR=2.52 95%CI 1.00–6.37). Interaction between handling diazinon concentrate and PON1 (192R) increased the risk of DF. No precipitating factor was identified in a case-crossover analysis. In the group without chronic illness those with 192R developed DF earlier (risk ratio 2.49 95%CI 1.03-6.02).

Conclusion

‘Dippers’ flu' and chronic ill-health attributed to dipping share a common polymorphism (192R). The interaction between handling diazinon concentrate and PON1 genotype supports the conclusion that organophosphates may cause DF. Sheep dippers who are still healthy but experience ‘dippers’ flu' may be wise to further limit exposures to organophosphates.