bluuebunny/crossref_metadata_2025 huggingface dataset:
Anti-adhesive effect of an acidic polysaccharide from Aloe vera L. var. chinensis (Haw.) Berger on the binding of Helicobacter pylori to the MKN-45 cell line
Authors: Xu Chen , Ruan Xiao-Ming , Li Hong-Sen , Guo Bin-Xin , Ren Xiao-Dong , Shuang Jing-Lei , Zhang Zhen
Published: October 2010

Objectives

The emergence of antibiotic-resistant Helicobacter pylori strains has necessitated a search for alternative therapies for the treatment of this infection. The aim of this study was to evaluate whether or not polysaccharide fractions from Aloe vera are effective in inhibiting the adherence of H. pylori in vitro.

Methods

Polysaccharide fractions were extracted from A. vera and subjected to carbohydrate analysis. The adhesive effect was determined by co-incubation of H. pylori and cells with polysaccharides followed by fluorescein isothiocyanate labelling and Gram staining in vitro. Inhibition of H. pylori growth and cellular viability was tested by agar diffusion and MTT assay.

Key findings

APS-F2 contained significant amounts of galacturonic acid, galactose and arabinose. APS-F1 was galacturonic acid-free and consisted of mannose, glucose and galactose. APS-F2 (0.1, 0.5 and 1.0 mg/ml) reduced the count of H. pylori attached to MKN45 cells to 88, 76 and 64%, respectively. APS-F1 did not show the same effect. Neither polysaccharide revealed an inhibitory effect on the growth of H. pylori or cell viability. In addition, APS-F2 was shown to have a potent anti-adhesive effect against Escherichia coli.

Conclusions

The results show that the acidic polysaccharide from A. vera has a potent anti-adhesive effect against H. pylori in vitro. However, there have yet to be any in-vivo studies to demonstrate the clinical relevance of this finding.
Characterisation of fenofibrate dissolution delivered by a self-microemulsifying drug-delivery system
Authors: Wei Jyh-Ding , Ho Hsiu-O , Chen Chien-Ho , Ke Wen-Tin , Chen Eric Tsu-Hsin , Sheu Ming-Thau
Published: October 2010

Objectives

This study attempted to characterise the in-vitro release profiles of fenofibrate (FFB) from a self-microemulsifying drug-delivery system (SMEDDS) for optimising formulation factors and dissolution conditions for in-vivo absorption.

Methods

The study was conducted by profiling the release of FFB formulated with either a complete solution or a micronised dispersion system (MDS) in a SMEDDS composed of medium-chain triglyceride (MCT) oil and surfactant mixtures (Smix) of TPGS and Tweens at different ratios (Km = TPGS/Tweens), with and without adding water. Optimised FFB SMEDDS formulations were then selected for in-vivo bioavailability study.

Key findings

The release rates of FFB from TPGS/Tween 20 systems were faster than those from TPGS/Tween 80 systems at the same Km value. In both systems, the release rates of FFB increased with a decrease in the Km value. Furthermore, both the release rates and the amounts of FFB from MDS in the water medium decreased with an increasing percentage of Smix added to both water contents. However, the release rates and amounts of FFB from MDSs increased with an increasing percentage of Smix in a 0.025 M sodium lauryl sulfate (SLS) solution. It was further illustrated that the release of FFB from SMEDDSs was complete within 30 min in both the 0.025 M SLS solution and water medium, but the release of FFB from Tricor® or MDSs was limited in water medium. An optimised FFB SMEDDS with either Tween 20(E5(20)) or Tween 80(E5(80)) and one MDS were selected for a pharmacokinetic study to compare with Tricor®. The results demonstrated that the area under the receiver operating curve and Cmax values were in the order of Tricor® > E5(80) ≅ E5(20) > MDS and Tricor® ≅ E5(80) > E5(20) > MDS, respectively.

Conclusions

The absorption of drug carried by SMEDDS might not be enhanced as a result of the smaller volume of water taken with oral administration of SMEDDSs and the agitation rate of the gastrointestinal tract not being strong enough to efficiently promote the self-microemulsification process to facilitate the in-vivo dissolution rate.
Effect of telmisartan in limiting the cardiotoxic effect of daunorubicin in rats
Authors: Arozal Wawaimuli , Watanabe Kenichi , Veeraveedu Punniyakoti T , Thandavarayan Rajarajan A , Harima Meilei , Sukumaran Vijayakumar , Suzuki Kenji , Kodama Makoto , Aizawa Yoshifusa
Published: October 2010

Objectives

Studies have suggested that angiotensin receptor blockers may exert a protective role towards doxorubicin-induced cardiotoxicity, but they have not been extensively investigated in this area. We therefore investigated whether the co-treatment of telmisartan, an angiotensin (Ang II) type-1 receptor blocker, might offer protection against daunorubicin cardiotoxic properties in rats.

Methods

Daunorubicin was administered at 3 mg/kg/day every other day for 12 days. Telmisartan was administered orally every day for 12 days.

Key findings

Daunorubicin-treated rats showed cardiac toxicity, evidenced by worsening cardiac function, evaluated by haemodynamic status and echocardiography, elevation of malondialdehyde level and a decreased level of total glutathione peroxidase activity in the heart tissue. These changes were reversed by treatment with telmisartan. Furthermore, telmisartan also downregulated matrix metalloproteinase-2 expression, attenuated the increased protein expression of p22phox, p47phox, p67phox, nuclear factor kappa B and Nox4 in heart tissue, and reduced oxidative-stress-induced DNA damage, which was evaluated by the expression of 8-hydroxydeoxyguanosine. Moreover, telmisartan reduced the myocardial apoptosis induced by daunorubicin.

Conclusions

The present study indicates that telmisartan may improve cardiac function by inhibiting the action of Ang II via AT-1R, which reverses oxidative stress and myocardial apoptosis. This suggests a beneficial effect of telmisartan treatment in the prevention of daunorubicin-induced cardiotoxicity.
Isoflurane preconditioning increases endothelial cell tolerance to in-vitro simulated ischaemia
Authors: Feng Jifeng , Zuo Zhiyi
Published: October 2010

Objectives

Isoflurane preconditioning has been shown to protect endothelial cells against lipopolysaccharide and cytokine induced injury. This study was designed to determine whether isoflurane preconditioning increased endothelial cell tolerance to ischaemia.

Methods

Bovine pulmonary arterial endothelial cells were exposed or not exposed to various concentrations of isoflurane for 1 h. After a 30-min isoflurane-free period, cells were subjected to oxygen-glucose deprivation (OGD) for 3 h and reoxygenation for 1 h. Lactate dehydrogenase release from cells was used to measure cell injury. In some experiments, various protein kinase C (PKC) inhibitors and ATP-sensitive potassium channel (KATP channel) inhibitors were present from 30 min before isoflurane treatment to the end of isoflurane treatment.

Key findings

Isoflurane preconditioning dose-dependently decreased the OGD induced lactate dehydrogenase release. This protection was inhibited by 2 µM chelerythrine, a general PKC inhibitor, or 10 µM Gö6976, an inhibitor for the conventional PKCs. This protection was also inhibited by 0.3 µM glybenclamide, a general KATP channel inhibitor, and 500 µM 5-hydroxydecanoate, a mitochondrial KATP channel blocker. In addition, pretreatment with 100 µM diazoxide, a KATP channel activator, for 1 h also reduced OGD induced endothelial cell injury. This diazoxide induced protection was inhibited by chelerythrine.

Conclusions

The results suggest that isoflurane preconditioning induces endothelial protection against in-vitro simulated ischemia. This protection may be mediated at least in part by conventional PKCs and mitochondrial KATP channels. The results also indicate that PKCs may be downstream of KATP channels in causing endothelial protection.
Pharmacy services at admission and discharge in adult, acute, public hospitals in Ireland
Authors: Grimes Tamasine , Duggan Catherine , Delaney Tim
Published: October 2010

Objectives

To describe hospital pharmacy involvement in medication management in Ireland, both generally and at points of transfer of care, and to gain a broad perspective of the hospital pharmacy workforce.

Methods

A survey of all adult, acute, public hospitals with an accident and emergency (A&E) department (n = 36), using a semi-structured telephone interview.

Key findings

There was a 97% (n = 35) response rate. The majority (n = 25, 71.4%) of hospitals reported delivery of a clinical pharmacy service. On admission, pharmacists were involved in taking or verifying medication histories in a minority (n = 15, 42.9%) of hospitals, while few (n = 6, 17.1%) deployed staff to the A&E/acute medical admissions unit. On discharge, the majority (n = 30, 85.7%) did not supply any take-out medication, a minority (n = 5, 14.3%) checked the discharge prescription, 51.4% (n = 18) counselled patients, 42.9% (n = 15) provided medication compliance charts and one hospital (2.9%) communicated with the patient's community pharmacy. The number of staff employed in the pharmacy department in each hospital was not proportionate to the number of inpatient beds, nor the volume of admissions from A&E. There were differences identified in service delivery between hospitals of different type: urban hospitals with a high volume of admissions from A&E were more likely to deliver clinical pharmacy.

Conclusions

The frequency and consistency of delivering pharmacy services to facilitate medication reconciliation at admission and discharge could be improved. Workforce constraints may inhibit service expansion. Development of national standards of practice may help to eliminate variation between hospitals and support service development.
Identification of Material Constitutive Laws for Machining—Part I: An Analytical Model Describing the Stress, Strain, Strain Rate, and Temperature Fields in the Primary Shear Zone in Orthogonal Metal Cutting
Authors: Shi Bin , Attia Helmi , Tounsi Nejah
Published: October 2010

To achieve high performance machining, modeling of the cutting process is necessary to predict cutting forces, residual stresses, tool wear, and burr formation. A major difficulty in the modeling of the cutting process is the description of the material constitutive law to reflect the severe plastic deformation encountered in the primary and the secondary deformation zones under high strains, strain rates, and temperatures. A critical literature review shows that the available methods to identify the material constitutive equation for the cutting process may lead to significant errors due to their limitations. To overcome these limitations, a novel methodology is developed in this study. Through conceptual considerations and finite element simulations, the characteristics of the stress, strain, strain rate, and temperature fields in the primary shear zone were established. Using this information and applying the principles of the theory of plasticity, heat transfer, and mechanics of the orthogonal metal cutting, a new distributed primary zone deformation model is developed to describe the distributions of the effective stress, effective strain, effective strain rate, and temperature in the primary shear zone. This analytical model is assessed by comparing its predictions with finite element simulation results under a wide range of cutting conditions using different materials. Experimental validation of this model will be presented in Part II of this study.
Identification of Material Constitutive Laws for Machining—Part II: Generation of the Constitutive Data and Validation of the Constitutive Law
Authors: Shi Bin , Attia Helmi , Tounsi Nejah
Published: October 2010

This paper presents an integral methodology to obtain a wide range of constitutive data required for the identification of the constitutive equation used in simulating cutting processes. This methodology is based on combining the distributed primary zone deformation (DPZD) model developed in Part I (Shi et al., 2010, ASME J. Manuf. Sci. Eng., 132, p. 051008.) of this study with quasi-static indentation (QSI) tests, orthogonal cutting tests at room temperature (RT) and high temperature. The QSI tests are used to capture the material properties in the quasi-static conditions, which solve the unstable solutions for the coefficients of the constitutive law. The RT cutting tests are designed to fulfill the assumptions embedded in the developed DPZD model in order to provide the distributed constitutive data encountered in the primary shear zone. To capture the material behavior in the secondary shear zone, the orthogonal cutting tests with a laser preheating system are designed to raise the temperature in the primary zone to the level encountered in the secondary zone. As an application of the generated constitutive data, the Johnson–Cook model is identified for Inconel 718. This constitutive law is further validated using high speed split Hopkinson pressure bar tests and orthogonal cutting tests combined with finite element simulations. In comparison with the previous approaches reported in the open literature, the developed DPZD model and methodology significantly improve the accuracy of the simulation results.
Experimental and Numerical Characterization of the Cyclic Thermomechanical Behavior of a High Temperature Forming Tool Alloy
Authors: Leen Sean B. , Deshpande Aditya , Hyde Thomas H.
Published: October 2010

This paper describes high temperature cyclic and creep relaxation testing and modeling of a high nickel-chromium material (XN40F) for application to the life prediction of superplastic forming (SPF) tools. An experimental test program to characterize the high temperature cyclic elastic-plastic-creep behavior of the material over a range of temperatures between 20°C and 900°C is described. The objective of the material testing is the development of a high temperature material model for cyclic analyses and life prediction of SPF dies for SPF of titanium aerospace components. A two-layer viscoplasticity model, which combines both creep and combined isotropic-kinematic plasticity, is chosen to represent the material behavior. The process of material constant identification for this model is presented, and the predicted results are compared with the rate-dependent (isothermal) experimental results. The temperature-dependent material model is furthermore applied to simulative thermomechanical fatigue tests, designed to represent the temperature and stress-strain cycling associated with the most damaging phase of the die cycle. The model is shown to give good correlation with the test data, thus vindicating future application of the material model in thermomechanical analyses of SPF dies for distortion and life prediction.
Transient Analysis of Downtimes and Bottleneck Dynamics in Serial Manufacturing Systems
Authors: Chang Qing , Biller Stephan , Xiao Guoxian
Published: October 2010

In manufacturing industry, downtimes have been considered as major impact factors of production performance. However, the real impacts of downtime events and relationships between downtimes and system performance and bottlenecks are not as trivial as it appears. To improve the system performance in real-time and to properly allocate limited resources/efforts to different stations, it is necessary to quantify the impact of each station downtime event on the production throughput of the whole transfer line. A complete characterization of the impact requires a careful investigation of the transients of the line dynamics disturbed by the downtime event. We study in this paper the impact of downtime events on the performance of inhomogeneous serial transfer lines. Our mathematical analysis suggests that the impact of any isolated downtime event is only apparent in the relatively long run when the duration exceeds a certain threshold called opportunity window. We also study the bottleneck phenomenon and its relationship with downtimes and opportunity window. The results are applicable to real-time production control, opportunistic maintenance scheduling, personnel staffing, and downtime cost estimation.
Prospects for Large-Scale Solar Thermal Electricity Generation From the Libyan Desert: Technical Feasibility
Authors: Aldali Y. , Henderson D. , Muneer T.
Published: October 2010

The Great Sahara desert covers the entire range of Libyan longitude 11° 44′ to 23° 58′ E and a latitude range of 24° 17′ through to 30° 31′N, thus covering an area of 1,750,000 sq km and 88% of this land is desert. The authors have measured hourly solar radiation at Kufra oasis (24° 17′N, 23° 15′E) within the Libyan Desert and found it to be a most reliable and consistent energy resource — the rain fall averages a few mm every 30 years. With no cloud cover throughout the year, the measured noon clearness-index often exceeding 0.84 and availability of large volumes of potable water from underground aquifers, large-scale electrical generation warrants a serious feasibility study. This article presents the technical feasibility for Cylindrical Parabolic Concentrator (CPC) thermal energy conversion.
Exergy Analysis of Natural Gas ICE-Based CHP System
Authors: Zhao Xiling , Fu Lin , Zhang Shigang , Zhu Jianzhang , Huang Baomin , He Tao , Lai Zhonglian
Published: October 2010

A challenge for CHP (Combined heating and power) system is the efficient integration of distributed generation (DG) equipment with thermally-activated (TA) technologies. Tsinghua University focuses on laboratory and demonstration research to study the critical issues of CHP systems, advance the technology and accelerate its application. The Research performed at the Building Energy Research Center (BERC) Laboratory focuses on assessing the operational performance and efficiency of the integration of current DG and TA technologies. The test system is composed of a 70-kW natural gas-fired internal combustion engine (ICE) with various heat recovery units, such as a flue gas-to-water heat recovery unit (FWRU), a jacket water heat recovery unit (JRU), liquid desiccant dehumidification systems (LDS), an exhaust-gas-driven double-effect absorption heat pump (EDAHP), and a condensation heat recovery unit (CRU)). In the winter, the exhaust gas from the ICE is used in the FWRU (operation mode I) or used to drive the EDAHP directly, and the exhaust gas from the EDAHP is used in the CRU (operation mode II). The water flows from the CRU can be directed to the evaporator side of the EDAHP as the lower-grade heat source. The water flows from the condensation side of the EDAHP, in conjunction with the jacket water flows from the JRU, is used for heating. In summer, the exhaust gas from the ICE is used to drive the EDAHP for cooling directly, and the waste heat of the jacket water is used to drive the liquid desiccant dehumidification systems, to realize the separate control of heat and humidity. In this paper, the exergy and energy analysis has been done on operation mode I and II according to the actual testing results, and it is show that the exergy efficiency of operation mode II is improved by 1.5% than operation mode I, and the energy efficiency of operation mode II is improved by 11% than operation mode I. The only way to improve the whole CHP is to maximize the use of the heat recovered by the ICE and to utilize the remaining heat of exhaust gas in other waste-heat driven equipments capable of using low grade waste heat like the CRU.
Development of a Thermal Energy Storage System for Parabolic Trough Power Plants With Direct Steam Generation
Authors: Laing Doerte , Bauer Thomas , Lehmann Dorothea , Bahl Carsten
Published: October 2010

For future parabolic trough plants direct steam generation in the absorber pipes is a promising option for reducing the costs of solar thermal power generation. These new solar thermal power plants require innovative storage concepts, where the two phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e. for preheating of water and superheating of steam. A pinch analysis helps to recognize interface constraints imposed by the solar field and the power block and describes a way to dimension the latent and sensible components. Laboratory test results of a PCM test module with approx. 140 kg NaNO3, applying the sandwich concept for enhancement of heat transfer, are presented, proving the expected capacity and power density. The concrete storage material for sensible heat was improved to allow the operation up to 500 °C for direct steam generation. A storage system with a total storage capacity of approx. 1 MWh is described, combining a PCM module and a concrete module, which will be tested in 2009 under real steam conditions around 100 bar.
Simulation Study on a Hybrid Solid Oxide Fuel Cell (SOFC)–Heat Recovery Steam Generator (HRSG)–Gas Turbine in IGCC Power Plant
Authors: Rudra Souman , Sayem A. S. M. , Biswas S. K. , Lee Soonil , Kim Hyung Taek
Published: October 2010

The fuel cell model developed to this research is based on a solid oxide fuel cell (SOFC) integrated with a heat recovery steam generator (HRSG), a gas turbine (GT) and a steam turbine (ST). Three possible technological approaches are compared to suggest the desirable combine cycle. First approach indicates the generation of the required steam in the coupled SOFC and gas turbine cycle. Then the exhaust gas from gas turbine involves driving the HRSG. And the last one involves of using exhaust gases in the HRSG which drives the steam turbine by producing steam for additional power works. To achieve the more efficient conversation of the thermal energy to power output, the component design mainly HRSG and steam turbine have to be made in a great concern. And HRSG is considered as a triple pressure for the taken model. This article is also delineated the analysis of coal fed instead of normal methane gas fed, for the reforming power generation based on thermodynamic processes including CO2 Capture. External reforming in SOFC-HRSG plants fueled by high quality coal enhances efficiency due to improved exhaust heat recovery and higher voltage produced by higher hydrogen partial pressure in the anode inlet. For improving the whole cycle efficiency, power output generation from both SOFC and conventional system (steam turbine and gas turbine) are described as combine system. This model is simulated by the ASPEN plus software which is able to provide thermodynamic and parametric analysis to evaluate the effects of various parameters like air flow rate, temperature, pressure and fuel flow rate on the system performance. Some MATLAB simulations are also added to provide strong opinion for this model through this paper.
Economic Analysis of Liquefied Petroleum Gas Gasification Utilizing Solar Thermal Energy
Authors: Shi Guohua , Wang Songling , Jing Youyin , Gao Yuefen
Published: October 2010

Liquefied petroleum gas (LPG) is an important source of residential gas in China due to its advantages. Traditional LPG vaporizer mainly depends on electric heating as its heat source, which leads to high energy cost and can not meet the demand of energy conservation policy. For a community with 1000 families in Beijing, a new LPG gasification system utilizing solar thermal energy has been designed in this paper. This system uses hot water produced by a solar water heating system as vaporization heat source and uses an electric heater as assisted heat source. In order to understand the economic efficiency of the whole system better, we compare the economic feasibility of the new system with that of traditional LPG vaporization system using annual cost method (AC). In addition, a spreadsheet computer program is used in this paper for purpose of the sensitivity analysis of the parameters. The optimal operation life for each system is calculated. The result shows that the new system is more economical than the traditional system and is an environmentally friendly alternative.
Biodiesel Fueled Engine Generator With Heat Recovery: Comparing Biodiesel to Diesel Performance
Authors: Betz Fred , Archer David
Published: October 2010

Carnegie Mellon University’s departments of Architecture and Mechanical Engineering have designed and installed a biodiesel fueled engine-generator with heat recovery equipment to supply electric and thermal power to an office building on campus, the Intelligent Workplace (IW). The installation was completed in early September 2007, and was commissioned through April of 2008 with standard off-road low sulfur Diesel (LSD) fuel. Additional baseline testing was conducted with LSD until October 2008, when the transition was made to a 100% soybean oil based biodiesel. The turbocharged diesel engine-generator set is operated in parallel with the local electric utility and the campus steam grid. The system is capable of generating 25 kW of electric power while providing 18 kW of thermal power in the form of steam from an exhaust gas boiler and 19 kW in the form of heated water from the engine coolant. The steam is delivered to a double-effect Lithium-Bromide (Li-Br) absorption chiller, which supplies chilled water to the IW for space cooling in the summer or hot water for space heating in the winter. Furthermore, the steam can be delivered to the campus steam grid during the fall and spring when neither heating nor cooling is required in the IW. The thermal energy recovered from the coolant provides hot water for space heating in the winter, and for regenerating a solid desiccant dehumidification ventilation system in summer. All relevant temperatures, pressures, and flows for these systems are monitored via a building automation system. Pressure versus time versus crank angle measurements are recorded in each cylinder of the engine. Emissions of nitric oxide (NO), nitrogen dioxide (NO2), Particulate Matter (PM), carbon monoxide (CO) and carbon dioxide (CO2) are also monitored. The performance testing thus far indicates that biodiesel fuel performs just as well as Diesel fuel in the CHP system, providing similar amounts of electrical and thermal energy at the similar temperatures and flows at a similar overall efficiency. As expected, the engine consumes more biodiesel fuel due to the lower energy density of biodiesel fuel compared to LSD. Upon completion of the system performance testing with different types of biodiesel fuel, the operation of the engine generator with its heat recovery components will be integrated with the other HVAC components of the IW including a parabolic trough solar thermal driven Li-Br absorption chiller, a solid desiccant dehumidification ventilation system, and multiple types of fan coils and radiant heating and cooling devices. This integrated energy supply system is expected to reduce the IW’s primary energy consumption by half in addition to the 75% site energy savings already realized by architectural features as compared to the average US office space.
Simulation of Utility-Scale Central Receiver System Power Plants
Authors: Wagner Michael J. , Klein Sanford A. , Reindl Douglas T.
Published: October 2010

The operation of solar energy systems is necessarily transient. Over the lifetime of a concentrating solar power plant, the system operates at design conditions only occasionally, with the bulk of operation occurring under part-load conditions depending on solar resource availability. Credible economic analyses of solar-electric systems requires versatile models capable of predicting system performance at both design and off-design conditions. This paper introduces new and adapted simulation tools for power tower systems including models for the heliostat field, central receiver, and the power cycle. The design process for solar power tower systems differs from that for other concentrating solar power (CSP) technologies such as the parabolic trough or parabolic dish systems that are nearly modular in their design. The design of an optimum power tower system requires a determination of the heliostat field layout and receiver geometry that results in the greatest long-term energy collection per unit cost. Research presented in this paper makes use of the DELSOL3 code (Kistler, 1986) which provides this capability. An interface program called PTGEN was developed to simplify the combined use of DELSOL3 and TRNSYS. The final product integrates the optimization tool with the detailed component models to provide a comprehensive modeling tool set for the power tower technology.
Securing Our Transportation Future by Using Off-Peak Wind Energy to Recycle CO2 Into Fuels
Authors: Doty F. David , Holte Laura , Shevgoor Siddarth
Published: October 2010

Simulations have shown that it should be possible (within a relatively short time frame) to profitably synthesize high-purity carbon-neutral ethanol, gasoline, jet fuel, propylene, and many other hydrocarbons, in volumes that cannot be matched by any other renewable avenue, from captured CO2, water, and cheap off-peak low-carbon energy, notably form wind farms. The process, dubbed WindFuels, requires no biomass, and it is expected to solve the grid stability and energy storage challenges of wind energy. The process is based largely on the commercially proven technologies of wind energy, water electrolysis, and Fischer Tropsch Synthesis (FTS) chemistry. Wind energy is used to electrolyze water into hydrogen and oxygen. Some of the hydrogen is used in a process, the so-called reverse water gas shift (RWGS) reaction, that reduces CO2 to carbon monoxide (CO) and water. The CO and the balance of the hydrogen are fed into an FT reactor, similar to that commonly used to produce fuels and chemicals from coal or natural gas. Improved sub-processes have been simulated in detail, and key experiments will soon be carried out to help optimize process conditions. Conversion efficiencies (from input electrical to output chemical) are expected to approach 60%. Putting renewable hydrogen into liquid fuels solves the distribution and storage problems that have beset utilization of hydrogen in vehicles. Converting CO2 into fuels can eliminate the need for CO2 sequestration and reduce global CO2 emissions by 40% by mid-century. The amount of water needed for the renewable FTS (RFTS) process is an order of magnitude less than needed for biofuels. The atmosphere will eventually provide an unlimited source for CO2, though initially the CO2 would come from ammonia plants, biofuel refineries, cement factories, fossil power plants, and ore refineries. When the input energy is from off-peak wind and reasonable monetary credit is included for climate benefit, WindFuels could compete when petroleum is as low as $45/bbl.
Simulated Performance Studies of SOFC-GT Hybrid CHP Systems Fuelled by Biomass-Derived Producer Gas
Authors: Ghosh S. , Singh R. K.
Published: October 2010

This paper presents a conceptual model of a 200-kWe Solid Oxide Fuel Cell – Gas Turbine (SOFC-GT) plant operating on biomass derived synthetic gas. The plant also has a Heat Recovery Steam Generator (HRSG) integrated at the GT exhaust, producing low-pressure process steam. The SOFC has been considered to be of tubular cell construction and internally reforming type. The reaction kinetics of the reforming and shifting reactions have been integrated with the cell electrochemical model. Simulated thermodynamic performance of the modeled plant in terms of electrical power, efficiency and process heat is presented and analyzed. Influences of variations in operating pressure and gas composition, on the plant performance are also reported.
Simulation of a Solar Receiver-Reactor for Hydrogen Production
Authors: Neises Martina , Goehring Felix , Roeb Martin , Sattler Christian , Pitz-Paal Robert
Published: October 2010

The transient thermal behavior of two solar receiver-reactors for hydrogen production has been modeled using Modelica/Dymola. The simulated reactors are dedicated to carry out the same chemical reactions but represent two different development stages of the project HYDROSOL and two different orders of magnitude concerning reactor size and hydrogen production capacity. The process itself is a two step thermochemical cycle, which uses mixed iron-oxides as a redox-system. The iron-oxide is coated on a ceramic substrate, which is placed inside the receiver-reactor and serves on the one hand as an absorber for solar radiation and on the other hand as the reaction zone for the chemical reaction. The process consists of a water splitting step in which hydrogen is produced and a regeneration step during which the used redox-material is being reduced. The reactor is operated between these two reaction conditions in regular intervals with alternating temperature levels of about 800 °C for the water splitting step and 1200 °C for the regeneration step. Because of this highly dynamic process and because of fluctuating solar radiation during the day, a mathematical tool was necessary to model the transient behavior of the reactor for theoretical studies. Two models have been developed for two existing receiver-reactors. One model has been set up to simulate the behavior of a small scale test reactor, which has been built and tested at the solar furnace of DLR in Cologne. Results are very promising and show that the model is able to reflect the thermal behavior of the reactor. Another model has been developed for a 100 kWth pilot reactor which was set up at the Plataforma Solar de Almeri´a in Spain. This model is based on the first model but special geometrical features had to be adapted. With this model temperatures and hydrogen production rates could be predicted.
Characterization of Salt Hydrates for Compact Seasonal Thermochemical Storage
Authors: van Essen V. M. , Cot Gores J. , Bleijendaal L. P. J. , Zondag H. A. , Schuitema R. , Bakker M. , van Helden W. G. J.
Published: October 2010

This paper describes the characterization of four salt hydrates as potential thermochemical material for compact seasonal heat storage in the built environment. First, magnesium sulfate was investigated in detail using TG-DSC apparatus. The results of this study revealed that magnesium sulfate is able to store almost 10 times more energy than water of the same volume. However, the material was unable to take up water (and release heat) under practical conditions. A new theoretical study identified three salt hydrates besides magnesium sulfate as promising materials for compact seasonal heat storage: aluminum sulfate, magnesium chloride and calcium chloride. These salt hydrates (including magnesium sulfate) were tested in a newly constructed experimental setup. Based on the observed temperature lift under practical conditions, it was found that magnesium chloride was the most promising material of the four tested salt hydrates. However, both calcium chloride and magnesium chloride tend to form a gel-like material due to melting or formation of a solution. This effect is undesired since it reduces the ability of the material to take up water again. Finally, it was observed that performing the hydration at low-pressure will improve the water vapor transport in comparison to atmospheric pressure hydration.
R&D of Thermochemical Reactor Concepts to Enable Seasonal Heat Storage of Solar Energy in Residential Houses
Authors: Zondag H. A. , Schuitema R. , Bleijendaal L. P. J. , Cot Gores J. , van Essen V. M. , Van Helden W. G. J. , Bakker M.
Published: October 2010

About 30% of the energy consumption in the Netherlands is taken up by residences and offices. Most of this energy is used for heating purposes. In order to reduce the consumption of fossil fuels, it is necessary to reduce this energy use as much as possible by means of insulation and heat recovery. The remaining demand could be met by solar thermal, provided that an effective way would exist for storing solar heat.
ReflecTech® Mirror Film Attributes and Durability for CSP Applications
Authors: DiGrazia Michael , Gee Randy , Jorgensen Gary
Published: October 2010

Reflectors are an essential part of parabolic trough solar electric and other concentrating solar power (CSP) systems. Reflectors in CSP systems require a high reflectance over the solar wavelength spectrum and they must be durable to outdoor exposure and resist all forms of degradation over time. All utility-scale CSP systems installed to date use glass reflectors. Glass mirrors have maintained their reflectance very well in CSP environments, but they are susceptible to wind-related breakage and are expensive to transport and install. Alternative lower-cost reflectors are needed to reduce the cost of CSP systems [1]. ReflecTech® Mirror Film is a highly reflective polymer-based film co-developed with the National Renewable Energy Laboratory (NREL) for concentrating solar energy applications. The attributes of ReflecTech® Mirror Film and test results for weatherability are described herein. This paper discusses field and lab test results and properties of ReflecTech® Mirror Film, specifically: 1. Stability under ultraviolet (UV) light through accelerated testing and outdoor real-time testing. 2. Mechanical stability and resistance to moisture through water immersion tests for delamination and “tunneling”. 3. Mechanical resistance to high wind events common in utility-scale concentrating solar power applications. 4. Lighter weight and resistance to breakage that reduces transportation and installation costs, and allows greater design flexibility of concentrator geometries. 5. Lower initial cost compared with curved glass mirrors. To test for weatherability, reflector samples were subjected to controlled conditions more extreme than actual outdoor environments. NREL maintains a world-class testing capability for solar reflectors that includes a Solar Simulator (SS), QUV (an accelerated exposure chamber manufactured by Q-Lab Corp. that subjects materials to alternating cycles of light and condensation at elevated temperatures), and several WeatherOmeter® (WOM) exposure chambers that allow accelerated testing of reflector samples. In addition, samples of ReflecTech® Mirror Film have been subjected to ACUVEX® accelerated outdoor weathering tests (natural sunlight in Phoenix, AZ, concentrated 7 to 8 times with a Fresnel-reflector while the samples are cooled with a fan to near ambient conditions and sprayed with de-ionized water 8 min per natural sun hour). Immersion tests were also performed to test the resistance of ReflecTech® Mirror Film to extreme moisture. Test results compared ReflecTech® film performance to past film products like 3M’s ECP-300 and ECP-305+ which suffered from “tunneling” [2], a problem whereby the silver reflective layer delaminates from the polymer film in the presence of moisture.
Transportation Integrating Green Energy Resources (TIGER)™: A Solar-Biodiesel Hybrid Commuter Vehicle
Authors: Bhavnani Sushil H.
Published: October 2010

Over the past two decades, several options have emerged as alternatives to traditional internal combustion engine-powered transportation systems. The alternative power sources garnering the most commercial interest have been hydrogen fuel-cells, battery-powered electric, propane, biodiesel, ethanol, and compressed natural gas. “Transportation Integrating Green Energy Resources” (TIGER)™ is a prototype hybrid vehicle that optimizes consumer desire for performance, alternative fuels, and environmental emissions reduction. It is powered by a combination of an electric motor and a biodiesel internal combustion engine. It is a two-passenger vehicle with a solarelectric, zero-emissions primary energy source for the daily commute while still permitting long-range travel utilizing the range-extension provided by the biodiesel engine. The average daily commute in the United States is less than 50 miles. During daily commuting use, the vehicle will operate solely as a solar-electric car. The electric vehicle (EV) system will be charged by deployable solar cells on its top surface while it is parked in a sun-lit parking lot during the workday. This charge will be sufficient to replenish energy used during a 50-mile commute. The commute is patterned as being comprised of 40 mph segments representing travel on arterial city roads and a 70-mph segment representing interstate highway travel. The biodiesel engine functions as the secondary power source to permit long-range trips with a refueling stop planned for around 350 miles; comparable to a conventional vehicle. The paper will report key elements of the vehicle design, including trade-offs between energy efficiency and passenger comfort/safety. Details of the various sub-systems such as the energy sources, the hybrid drive-train, and subsystem integration will be presented.
Retrofitting CO2 Capture to Existing Power Plants as a Fast Track Mitigation Strategy
Authors: Chalmers Hannah , Gibbins Jon , Lucquiaud Mathieu
Published: October 2010

Carbon capture and storage (CCS) is often identified as an important technology for mitigating global carbon dioxide (CO2) emissions. For example, the IEA currently suggests that 160GW of CCS may need to be installed globally by 2030 as part of action to limit greenhouse gas concentrations to 550ppm-CO2eq, with a further 190GW CCS capacity required if a 450ppm-CO2eq target is to be achieved. Since global rollout of proven CCS technologies is not expected to commence until 2020 at the earliest this represents a very challenging build rate. In these circumstances retrofitting CO2 capture to existing plants, probably particularly post-combustion capture on pulverized coal-fired plants, could play an important role in the deployment of CCS as a global strategy for implementing CO2 emissions reductions. Retrofitting obviously reduces the construction activity required for CCS deployment, since fewer additional new power plants are required. Retrofitting CCS to an existing fleet is also an effective way to significantly reduce CO2 emissions from this sector of the electricity generation mix; it is obviously not possible to effect an absolute reduction in coal power sector CO2 emissions simply by adding new plants with CCS to the existing fleet. Although it has been proposed that plants constructed now and in the future can be ‘capture ready’, much of the existing fleet will not have been designed to be suitable for retrofit of CO2 capture. Some particular challenges that may be faced by utilities and investors considering a retrofit project are discussed. Since it is expected that post-combustion capture retrofits to pulverized coal plants will be the most widely applied option for retrofit to the existing fleet (probably regardless of whether base plants were designed to be capture ready or not), a review of the technical and potential economic performance of this option is presented. Power cycle performance penalties when capture is retrofitted need to be addressed, but satisfactory options appear to exist. It also seems likely that the economic performance of post-combustion capture retrofit could be competitive when compared to other options requiring more significant capital expenditure. Further work is, however, required both to develop a generally accepted methodology for assessing retrofit economics (including consideration of the implications of lost output after retrofit under different electricity selling price assumptions) and to apply general technical principles to case studies where site-specific constraints are considered in detail. The overall conclusion from the screening-level analysis reported in this paper is that, depending on project-specific and market-specific conditions, retrofit could be an attractive option, especially for fast track initial demonstration and deployment of CCS. Any unnecessary regulatory or funding barriers to retrofit of existing plants and to their effective operation with CCS should, therefore, be avoided.
Next Generation Oxy-Fired Systems: Potential for Energy Efficiency Improvement Through Pressurization
Authors: Clements Bruce R. , Zheng Ligang , Pomalis Richard
Published: October 2010

Oxy-fired combustion has been identified as a key technology needed for greenhouse gas mitigation because it is capable of producing a concentrated CO2 stream suitable for sequestration. This technology as applied to pulverized coal systems has recently been brought to a near-commercial status with several key world-wide demonstrations. A barrier to its adoption has been the large additional auxiliary power required for oxygen production and CO2 compression which results in low overall system efficiency. There have been various strategies proposed to address these efficiency issues. A very promising concept is the use of pressurized combustion in order to increase the system efficiency. The use of pressure increases the power requirement of the air separation system. However, pressurization increases the boiler and steam side efficiencies while decreasing the power requirement for the CO2 compression system. The use of pressure will also affect the performance and size of each piece of equipment within the system. This paper describes the efficiency benefit of using pressure as compared with a baseline ambient pressure oxy-fired system and a typical air-fired system. The technical aspects of various system layouts are presented, the overall efficiency is evaluated and the merits of specific configurations are discussed. Design issues of equipment associated with the fuel supply, furnace, ash removal, heat transfer and flame moderation systems are presented.
Structural Health Monitoring of Wind Turbine Blades
Authors: Barkley Walter C. , Jacobs Laura D. , Rutherford Mandy C.
Published: October 2010

Wind Turbine blade failures can occur in several modes, which may depend on the type of construction and load history. Cracking and delamination are two typical modes of blade failure (Fig. 1). A structural health monitoring (SHM) system can help to better understand warranty costs and warranty periods for the blades in wind turbines and predict imminent failure before it occurs. Currently, industry best practices are to increase the number of physical inspections when blades are approaching the end of their fatigue lives. Implementation of an in situ monitoring system would eliminate or greatly reduce the need for such physical inspections. Another benefit of such a monitoring system is that the life of any given component could be extended since real conditions would be monitored. The SHM system is designed to operate while the wind turbine is in service. This means that wireless communication options will be implemented. Because blade failures occur due to cyclic stresses in the blade material, the sensing system will focus on monitoring strain at various points. This paper describes a design and implementation scheme for a real time structural health monitoring system in order to better understand when blade replacement is necessary. Although not described in this research, the same concepts can also be applied to gearbox damage detection.
B-Raf Dependency
Authors: Foley John F.
Published: October 2010

More than 80% inhibition of ERK activity is required to induce regression of melanoma tumors.
Smoke Gets in Your Lungs
Authors: Mueller Kristen L.
Published: October 2010

Cigarette smoke promotes lung inflammation by hindering an enzyme that degrades an immune cell chemoattractant.
Mechanisms of Sperm-Egg Interactions: Between Sugars and Broken Bonds
Authors: Visconti Pablo E. , Florman Harvey M.
Published: October 2010

New evidence reveals a more complex scenario for early events in mammalian fertilization.