bluuebunny/crossref_metadata_2025 huggingface dataset:
Macrophage Apoptosis in Advanced Atherosclerosis
Authors: Tabas Ira , Seimon Tracie , Timmins Jenelle , Li Gang , Lim Wahseng
Published: September 2009

Plaque necrosis in advanced atheromata, which triggers acute atherothrombotic vascular events, is caused by the apoptosis of lesional macrophages coupled with defective phagocytic clearance of the dead cells. The central enabling event in macrophage apoptosis relevant to advanced atherosclerosis is the unfolded protein response (UPR), an endoplasmic reticulum (ER) stress pathway. The UPR effector CHOP (GADD153) amplifies release of ER Ca2+ stores, which activates a central integrator of apoptosis signaling, calcium/calmodulin‐dependent protein kinase II (CaMKII). CaMKII, in turn, leads to activation of pro‐apoptotic STAT1, induction of the death receptor Fas, and stimulation of the mitochondria‐cytochrome c pathway of apoptosis. While these pathways are necessary for apoptosis, apoptosis occurs only when the cells are also exposed to one or more additional “hits.” These hits amplify pro‐apoptotic pathways and/or suppress compensatory cell‐survival pathways. A second hit relevant to atherosclerosis is activation of pattern recognition receptors (PRRs), such as scavenger and toll‐like receptors. In vivo relevance is suggested by the fact that advanced human lesions express markers of UPR activation that correlate closely with the degree of plaque vulnerability and macrophage apoptosis. Moreover, studies with genetically altered mice have shown that ER stress and PRR activation are causative for advanced lesional macrophage apoptosis and plaque necrosis. In summary, a key cellular event in the conversion of benign to vulnerable atherosclerotic plaques is ER stress‐induced macrophage apoptosis. Further understanding of the mechanisms and consequences of this event may lead to novel therapies directed at preventing the clinical progression of atheromata.
An Osteoblast‐dependent Mechanism Contributes to the Leptin Regulation of Insulin Secretion
Authors: Hinoi Eiichi , Gao Nan , Jung Dae Young , Yadav Vijay , Yoshizawa Tatsuya , Kajimura Daisuke , Myers, Jr. Martin G. , Chua, Jr. Streamson C. , Wang Qin , Kim Jason K. , Kaestner Klaus H. , Karsenty Gerard
Published: September 2009

Our work focuses on genetic and molecular mechanisms for the reciprocal regulation of bone and energy metabolism orchestrated by leptin and osteocalcin. In the context of this reciprocal regulation, the finding that leptin inhibits insulin secretion by β cells while osteocalcin favors it is surprising. In exploring the molecular bases of this paradox we found that leptin, as is the case for most of its functions, uses a neuronal relay to inhibit insulin secretion. Cell‐specific gene‐deletion experiments revealed that a component of this neuronal regulation is the sympathetic innervation to osteoblasts. Under the control of leptin the sympathetic tone favors expression in osteoblasts of Esp, which inhibits the metabolic activity of osteocalcin. We further identify ATF4 as a transcription factor that regulates Esp expression and thereby insulin secretion and sensitivity. Taken together these data illustrate the tight connections between bone remodeling and energy metabolism and add further credence to the notion that the osteoblast is a bona fide endocrine cell type.
Inactivation of Listeria monocytogenes on Unpackaged and Vacuum‐Packaged Chicken Frankfurters Using Pulsed UV‐Light
Authors: Keklik N.M. , Demirci A. , Puri V.M.
Published: September 2009

ABSTRACT:  The effectiveness of pulsed UV‐light on the microbial load and quality of unpackaged and vacuum‐packaged chicken frankfurters was investigated. Samples were inoculated with Listeria monocytogenes Scott A on the top surfaces, and then treated with pulsed UV‐light for 5, 15, 30, 45, and 60 s at 5, 8, and 13 cm distance from the quartz window in a pulsed UV‐light chamber. Log reductions (CFU/cm2) on unpackaged samples were between 0.3 and 1.9 after 5‐s treatment at 13 cm and 60‐s treatment at 5 cm, respectively. Log reductions on packaged samples ranged from 0.1 to 1.9 after 5‐s treatment at 13 cm and 60‐s treatment at 5 cm, respectively. The temperature changes of samples and total energy (J/cm2) received at each treatment condition were monitored. The extent of lipid peroxidation and the color were determined by thiobarbituric acid‐reactive substances (TBARS) test and CIELAB color method, respectively. Lipid peroxidation of samples did not change significantly (P > 0.05) after mild (5‐s treatment at 13 cm) and moderate (30‐s treatment at 8 cm) treatments. Significant differences (P < 0.05) in color parameters were observed after treatments of both unpackaged and packaged samples. Packaging material was also analyzed for mechanical properties. The elastic modulus, yield strength, percent elongation at yield point, maximum tensile strength, and percent elongation at break did not change significantly (P > 0.05) after mild treatment. Overall, this study demonstrated that pulsed UV‐light has a potential to decontaminate ready‐to‐eat (RTE) poultry‐based food products.
Edible Apple Film Wraps Containing Plant Antimicrobials Inactivate Foodborne Pathogens on Meat and Poultry Products
Authors: Ravishankar Sadhana , Zhu Libin , Olsen Carl W. , McHugh Tara H. , Friedman Mendel
Published: September 2009

ABSTRACT:  Apple‐based edible films containing plant antimicrobials were evaluated for their activity against pathogenic bacteria on meat and poultry products. Salmonella enterica or E. coli O157:H7 (107 CFU/g) cultures were surface inoculated on chicken breasts and Listeria monocytogenes (106 CFU/g) on ham. The inoculated products were then wrapped with edible films containing 3 concentrations (0.5%, 1.5%, and 3%) of cinnamaldehyde or carvacrol. Following incubation at either 23 or 4 °C for 72 h, samples were stomached in buffered peptone water, diluted, and plated for enumeration of survivors. The antimicrobial films exhibited concentration‐dependent activities against the pathogens tested. At 23 °C on chicken breasts, films with 3% antimicrobials showed the highest reductions (4.3 to 6.8 log CFU/g) of both S. enterica and E. coli O157:H7. Films with 1.5% and 0.5% antimicrobials showed 2.4 to 4.3 and 1.6 to 2.8 log reductions, respectively. At 4 °C, carvacrol exhibited greater activity than did cinnamaldehyde. Films with 3%, 1.5%, and 0.5% carvacrol reduced the bacterial populations by about 3, 1.6 to 3, and 0.8 to 1 logs, respectively. Films with 3% and 1.5% cinnamaldehyde induced 1.2 to 2.8 and 1.2 to 1.3 log reductions, respectively. For L. monocytogenes on ham, carvacrol films induced greater reductions than did cinnamaldehyde films at all concentrations tested. In general, the reduction of L. monocytogenes on ham at 23 °C was greater than at 4 °C. Added antimicrobials had minor effects on physical properties of the films. The results suggest that the food industry and consumers could use these films as wrappings to control surface contamination by foodborne pathogenic microorganisms.
Gel Strengthening Effect of Wood Extract on Surimi Produced from Mackerel Stored in Ice
Authors: Balange A.K. , Benjakul S. , Maqsood S.
Published: September 2009

ABSTRACT:  The effect of ethanolic kiam wood extract (EKWE) and commercial tannin (CT) on the gel properties of surimi produced from mackerel (Rastrelliger kanagurta) stored in ice for different times (0 to 12 d) was studied. During 12 d of iced storage, pH, total volatile base (TVB), trimethylamine (TMA), and trichloroacetic acid (TCA)‐soluble peptide contents as well as thiobarbituric acid‐reactive substances (TBARS) of mackerel mince increased while myosin heavy chain (MHC) band intensity decreased continuously (P < 0.05). The result suggested that deterioration, protein degradation, and lipid oxidation proceeded with increasing storage time. For corresponding surimi, TVB and TMA were almost removed and TBARS and TCA soluble peptide contents were decreased. Conversely, MHC became more concentrated. Decreases in gel‐forming ability of surimi were observed when fish used as raw material were stored in ice for a longer time, regardless of EKWE or CT addition. Whiteness of surimi gel decreased and expressible moisture increased especially when the storage time increased. However, superior breaking force and deformation of surimi gel with 0.15% EKWE or 0.30% CT added, compared to those of the control gel were observed during the first 6 d of the storage. Thereafter, EKWE and CT had no gel enhancing effect on surimi. Therefore, freshness was a crucial factor determining gel enhancing ability of EKWE or CT toward mackerel surimi.
Microwave Oven Heating for Inactivation of Listeria Monocytogenes on Frankfurters before Consumption
Authors: Rodríguez‐Marval Mawill , Geornaras Ifigenia , Kendall Patricia A. , Scanga John A. , Belk Keith E. , Sofos John N.
Published: September 2009

ABSTRACT:  Microwave oven heating was evaluated for inactivation of Listeria monocytogenes on inoculated and stored frankfurters. Frankfurters formulated without/with 1.5% potassium lactate and 0.1% sodium diacetate were inoculated with L. monocytogenes (1.9 ± 0.2 log CFU/cm2), vacuum‐packaged, and stored (4 °C) to simulate conditions prior to purchase by consumers. At storage days 18, 36, and 54, packages were opened and placed at 7 °C, simulating aerobic storage in a household refrigerator. At 0, 3, and 7 d of aerobic storage, 2 frankfurters were placed in a bowl with water (250 mL) and treated in a household microwave oven at high (1100 W) power for 30, 45, 60, or 75 s, or medium (550 W) power for 60 or 75 s. Frankfurters and the heating water were analyzed for total microbial counts and L. monocytogenes populations. Exposure to high power for 75 s reduced pathogen levels (0.7 ± 0.0 to 1.0 ± 0.1 log CFU/cm2) to below the detection limit (<−0.4 log CFU/cm2) on frankfurters with lactate/diacetate, even after 54 d of vacuum‐packaged storage followed by 7 d of aerobic storage. For frankfurters without lactate/diacetate, high power for 75 s caused reductions between > 1.5 and 5.9 log CFU/cm2 from control levels of 1.5 ± 0.1 to 7.2 ± 0.5 log CFU/cm2. Depending on treatment and storage time, the water used to reheat the frankfurters had viable L. monocytogenes counts of <−2.4 to 5.5 ± 0.5 log CFU/mL. The results indicated that frankfurters should be reheated in a microwave oven at high power for 75 s to inactivate up to 3.7 log CFU/cm2 of L. monocytogenes contamination.
Myofibroblasts in the normal conjunctival surface
Authors: Aguilar Ximena , Hallberg David , Sundelin Karin , Hanson Charles , Stenberg Kristina , Brune Mats , Stenevi Ulf
Published: September 2009

Purpose:  To investigate the occurrence of myofibroblasts (MFBs) in the normal conjunctival surface and to evaluate any anatomical and time‐related variations.

Methods:  MFBs were screened among healthy individuals (35 eyes) by collecting impression cytology (IC) samples from the bulbar conjunctiva. A cohort of volunteers (12 eyes) was followed for 1 year by taking two to five imprints every month. MFBs were identified by immunohistochemical localization of the MFB marker α‐smooth‐muscle actin (α‐SMA).

Results:  Using a filter imprint technique, MFBs were found consistently in 94% of samples from the conjunctival surface of participating individuals. The overall MFB levels, expressed as percentage of all cells on the filter, were highest in March–May [mean 4.1%, standard deviation (SD) ± 1.5] and lowest in December–February (mean 1.2%, SD ± 0.5). The difference was statistically significant [p < 0.0005, Friedman test, one‐way repeated measures analysis of variance (anova)]. Moreover, there was a clear divergence of MFB density between the nasal, temporal, superior and inferior bulbar conjunctiva (mean 1.7%, 1.9%, 22% and 9.7%, respectively).

Conclusion:  MFBs, known as a cellular constituent of granulation tissue in wound healing, occur in the normal conjunctival surface, which is a novel finding. Our results also show that MFB level follows a seasonal variation pattern in a temperate climate, increasing in April–September and decreasing in October–March. This variation might reflect a degree of a transient or ongoing state of tissue repair after conjunctival trauma or stress caused by exposure to environmental factors.
Surfactant Protein C in Canine Pulmonary Fibrosis
Authors: Eriksson M. , Von Euler H. , Ekman E. , Nordling K. , Häggström J. , Johansson J.
Published: September 2009

Background:Canine pulmonary fibrosis (CPF) occurs most commonly in West Highland White Terriers. The differing incidences of CPF among dog breeds suggest that genetic factors contribute to its pathophysiology. Pulmonary fibrosis in humans is associated with mutations in the gene coding for lung surfactant protein C (SP‐C) (SFTPC).

Hypothesis/Objectives:To investigate the histopathologic changes and SP‐C composition and genetic structure in dogs with CPF.

Animals:Five dogs with PF, 2 dogs with other lung diseases, and 3 healthy dogs.

Methods:Lung tissue from dogs with clinically suspected CPF and 5 control cases was analyzed histopathologically. Bronchoalveolar lavage fluid (BALF) collected postmortem from 3 terriers with histopathologically confirmed pulmonary fibrosis and the 5 controls were analyzed by Western blots, and the exons ofSFTPCwere sequenced for 2 dogs with PF and 1 dog with other lung disease.

Results:SP‐C could not be detected in BALF of 1 dog with PF, although SP‐B was present. A mutation was detected inSFTPCexon 5 of this dog. From 2 dogs with PF and in all 5 control dogs SP‐B and SP‐C were detected in BALF.

Conclusions:Taken together, the results indicate that canine and human lung fibrosis share histopathologic features and that analysis of SP‐C and its gene in a larger set of dogs with PF is warranted.
Thermodynamic Performance Optimization of Reciprocating Internal Combustion (IC) Engines
Authors: Adebiyi George A. , Srinivasan Kalyan K. , Gibson Charles M.
Published: September 2009

Reciprocating IC engines are traditionally modeled as operating on air standard cycles that approximate indicator diagrams obtained in experiments on real engines. These indicator diagrams can best be approximated by the dual cycle for both gasoline and diesel engines. Analysis of air standard cycles unfortunately fails to capture second law effects such as exergy destruction due to the irreversibility of combustion. Indeed, a complete thermodynamic study of any process requires application of both the first and second laws of thermodynamics. This article gives a combined first and second law analysis of reciprocating IC engines in general with optimization of performance as primary goal. A practical dual-like cycle is assumed for the operation of a typical reciprocating IC engine and process efficiencies are assigned to allow for irreversibilities in the compression and expansion processes. The combustion process is modeled instead of being replaced simply by a heat input process to air as is common in air standard cycle analysis. The study shows that performance of the engine can indeed be optimized on the basis of geometrical design parameters such as the compression ratio as well as the air-fuel ratio used for the combustion.
Selection of Airfoils for Straight-Bladed Vertical Axis Wind Turbines Based on Desirable Aerodynamic Characteristics
Authors: Islam Mazharul , Amin M. Ruhul , Ting David S.-K. , Fartaj Amir
Published: September 2009

Selection of the airfoil is crucial for better aerodynamic performance and dimensions of a smaller-capacity SB-VAWT which can compete with conventional energy sources in niche markets like urban areas and off-grid remote applications for diversified applications. Airfoil related design changes also have the potential for increasing the cost effectiveness of VAWTs. Recently, Islam et. al [1] have identified the desirable features of an ideal airfoil for smaller capacity SB-VAWT to improve its starting characteristics and overall performance. They have shortlisted several aerodynamic characteristics of the desirable airfoil. Based on these desirable aerodynamic characteristics, an attempt has been made in this paper to shortlist ten prospective candidate airfoils for smaller-capacity SB-VAWT. This is done using both experimental and analytical characteristics. Nine performance indices have been defined in this paper in light of desirable aerodynamic characteristics to select best performing airfoil. These performance indices are utilized for considering the following desirable aerodynamic characteristics: (i) stall angle at low Reynolds number, (ii) width of the drag bucket, (iii) zero-lift-drag coefficient, (iv) Cl/Cd ratio, (v) maximum lift-coefficient, (vi) deep-stall angle, (vii) roughness sensitivity, (viii) trailing edge noise generation, and (ix) pitching moment. Here, Cl and Cd are coefficients of lift and drag respectively. After determining the value of the performance indices and rating of the candidate airfoils, the most promising airfoil is selected. Among the ten candidate airfoils, overall rating of NASA LS(1)-0417 has been found to be the best.
Thermodynamic Analysis of Advance Technology Combined Cycle Power Plant Employing Water/Steam Closed Loop Cooling in Gas Turbine
Authors: Yadav J. P. , Singh Onkar
Published: September 2009

Present paper deals with the thermodynamic analysis of advanced technology gas/steam combined cycle based power plant having closed loop cooling in gas turbine stages employing water / steam as coolants. Advanced technology combined cycle configuration as manufactured by some major power plant manufacturers has been considered for study here. Results have been obtained for the cycle pressure ratios varying between 12 to 20 and turbine inlet temperatures varying in 1400 K to 1700 K. Influence of water and steam coolants upon the overall cycle performance has been analyzed here.
Energy Analysis of Cooling Pump in Internal Combustion Engine
Authors: Mahlia T. M. I. , Husnawan M. , Masjuki H. H. , Chow K. V. , Low T. S. , Liaw A. W. J.
Published: September 2009

This study is conducted to analyze the energy use by cooling pump in internal combustion engine (ICE). The main focus of the experiment is to analyze the radiator heat transfer and the cooling pump power. The heat transfer rate of radiator is determined by conducting an experiment on an ICE. Thermocouples and an anemometer are used for temperature and air velocity measurement respectively. The cooling pump power is determined through dynamometer test. These experiments are conducted only for engine speed range of 1000rpm to 1500rpm to avoid overheating when belt is dismantled. The engine running at 1000rpm to 1500rpm produces about 1.2kW to 2.5kW power and rejects heat at rate of 0.20kW to 0.3kW, representing 13.0% to 19.1% of the total energy lost. The cooling pump power is approximately 0.13–0.19kW which is approximately 7.6% of the engine power output.
Hybrid Systems Using Solid Oxide Fuel Cell and Polymer Electrolyte Fuel Cell
Authors: Yoshida Hideki , Amaha Shinji , Yakabe Hisataka
Published: September 2009

In this paper, the concept of an SOFC (Solid Oxide Fuel Cell) and PEFC (Polymer Electrolyte Fuel Cell) hybrid system is presented. Large-scale SOFC systems operated in a thermally self-sustainable state produce excess heat. The excess heat can be used for producing hydrogen. Several variations of hydrogen production systems are presented here. One way is to produce the hydrogen by using an extra reformer. Another way is purifying the off-fuel of SOFCs. The produced hydrogen can be used as the fuel for PEFCs. The overall electrical efficiency of a combination of an SOFC and PEFCs is higher than that of a standalone SOFC. When the hydrogen produced by purifying the off-fuel of the SOFC is used as the fuel for PEFCs, the overall electrical conversion efficiency increases by around 20%.
Integrate CHP to Improve Overall Corn Ethanol Economics
Authors: Meckler Milton , Ho Son H.
Published: September 2009

This paper presents a practical solution to improve the current overall corn ethanol economics. It is our intent in this paper also to focus our attention on extraction of corn ethanol and distillers dry grains with solubles (DDGS) employing the dry milling process since it appears to offer the greatest opportunity for substantial improvement. Alternate corn ethanol wet mill processing for the extraction of gluten protein meal for livestock food is also briefly described. A hybrid integrated steam jet refrigeration/freeze concentration system (ISJR/FCS) is proposed for the extraction of corn ethanol and DDGS in dry milling process. Technical feasibility of substantially reducing corn ethanol first cost on a life cycle basis as well as current operational costs and greenhouse gas emissions is demonstrated employing an actual case study.
Simulation Model and Analysis of a Small Solar-Assisted Refrigeration System: Dynamic Simulation and Optimization
Authors: Calise F. , Dentice d’Accadia M. , Palombo A. , Vanoli L.
Published: September 2009

In this paper, a complete zero-dimensional transient simulation model of a solar-assisted refrigeration plant is presented. In addition, a case study is discussed, aiming at determining the optimal configuration of the system, from the energetic point of view, in a specific application. The system under analysis consisted of several components: evacuated solar collectors, circulation pumps, variable speed pump, water storage tanks, auxiliary heater, single-stage H2O-LiBr absorption chiller, cooling tower, feedback controller, on/off hysteresis controller, single lumped capacitance building and controllers. The simulation was performed using the TRNSYS environment which is provided by a large component library. This software also includes a detailed database with weather parameters for several European cities. The system and the building were simulated using TRNSYS built in models. The system was simulated using specially designed control strategies and varying the main design variables. In particular, a variable speed pump on the solar collector was implemented in order to maximize the tank temperature and minimizing the heat losses. Finally a sensitivity analysis was also performed in order to calculate the set of synthesis/design parameters that maximize the total system efficiency.
Irreversibility Analysis of a Vapor Compression Cascade Refrigeration Cycle
Authors: Kilicarslan Ali , Mu¨ller Norbert
Published: September 2009

Hydrocarbon based energy sources such as coal, oil and natural gas have been diminishing in an increasing speed. Instead of finding alternative energy sources, we have to use the available sources more effectively. By means of the irreversibility analysis, we can determine the factors or conditions that cause the inefficiencies in any energy system. In this study, irreversibility analysis of a compression cascade refrigeration cycle that consists of a high and low temperature cycles is presented. In the high temperature cycle, the refrigerants from different classes, namely R12 (CFC), R22 (HCFC), R134a (HFC) and R404a (Azeotropic) are selected as working fluids. In the low temperature cycle, R13 is only used as a working fluid. Irreversibility analysis of refrigerant pairs, namely R12-R13, R22-R13, R134a-R13, and R404a-R13 are carried out in a compression cascade refrigeration cycle by a computer code developed. The effects of evaporator temperature, condenser temperature, and the temperature difference between the saturation temperatures of the lower and higher temperature cycles in the heat exchanger (ΔT) and the polytropic efficiency on irreversibility of the system are investigated. The irreversibility of the cascade refrigeration cycle decreases as the evaporator temperature and polytropic efficiency increase for all of the refrigerant couples considered while the irreversibility increases with the increasing values of the condenser temperature and ΔT. In the whole ranges of evaporator temperature (−65°C / −45°C), condenser temperature (30–50°C), ΔT (2–16K) and polytropic efficiency (%50/%100), the refrigerant pair R12-R13 has the lowest values of irreversibilities while the pair R404a-R13 has the highest ones. At the lower condenser temperature (<30°C) and higher polytropic efficiencies (85%–95%), the refrigerant couples except for R404a-R13 have approximately the same values of irreversibility.
Conventional Power Plants Equipped With Systems for CO2 Emission Abatement
Authors: Gambini Marco , Vellini Michela
Published: September 2009

This paper presents the results from an evaluation of the performance and cost of Italian power plants (a steam cycle power plants — 500 MW — fed by coal and a combined cycle power plant — 300 MW — fed by natural gas) with CO2 emissions control equipment to achieve a fixed reduction in atmospheric discharge of carbon dioxide (CO2) and so to accomplish the CO2 emission targets established by the Kyoto Protocol. The reduction of the CO2 content in the flue gas is achieved by amine scrubbing (CO2 removal), removal of water from CO2 (drying), compression to pipeline pressure; transport and storage are not considered. The paper presents an economic evaluation of the CO2 abatement cost and compares it with the cost of allowances in the Emission Trading System and with the payment of the penalty for the emissions in excess when there is no CO2 quota available on the market.
Advancing Thermoacoustics Through CFD Simulation Using Fluent
Authors: Zink Florian , Vipperman Jeffrey S. , Schaefer Laura A.
Published: September 2009

From the time mechanical refrigeration was first introduced, its use has significantly increased. In general, cooling is achieved with vapor compression machines that use specific refrigerants (blends of hydrogen, carbon, fluorine and chlorine in various mixing ratios) that can be tailored to create cooling at any required temperature level. Each refrigerant exhibits a specific global warming potential and ozone depletion potential in the atmosphere by absorbing infrared radiation and breaking down of ozone molecules. Since the adverse effects of those substances have been discovered, the field of refrigeration has been moving away from conventional refrigerants, and searching for better alternatives. Thermoacoustic refrigeration is such an alternative that can provide cooling to essentially any required temperature level without using any environmentally harmful substances. It is presently a niche technology that can be expanded into a broader market, primarily if the sizing problem can be solved. Currently, the most efficient thermoacoustic refrigerators are used in industrial settings. This work explores the possibility of decreasing the footprint of these refrigerators by utilizing a coiled resonator. A CFD analysis has been developed and first results in regard to coiled resonators are shown and discussed.
Multi-Objective Thermoeconomic Optimization of Coupling MSF Desalination With PWR Nuclear Power Plant
Authors: Khoshgoftar Manesh Mohammad Hasan , Amidpour Majid , Hamedi Mohammad Hosein
Published: September 2009

Thermodynamic simulation programs are widely used for designing complex thermal systems but most of them don’t incorporate second law optimization techniques. In this study, an efficient optimization strategy is presented, which integrates a well-known Evolutionary Algorithms optimization technique with a professional power plant and cogeneration simulator, so as perform exergoeconomic optimization of complex thermal systems and generating combined pinch and exergy representations. This paper deals with the application of an evolutionary algorithm to multi-objective thermoeconomic optimization of coupling desalination plant with pressurized water reactor. The thermodynamic simulation of this plant has been performed in THERMOFLEX simulator. An Excel Add-in called THERMOFLEX Link has been developed to calculate the exergy of each stream from a THERMOFLEX simulation results. In addition, computer code has been developed for thermoeconomic and improved combined pinch-exergy analysis in MATLAB environment. Both design configuration and the process variables are optimized simultaneously. The optimization algorithm can choose among several design options included in a superstructure of the feed water heaters and MSF desalination in dual purpose plant. For the assumptions and simplifications made in this study, a 3000 MWth PWR power plant similar to Bushehr power plant has been considered.
Multiphase Flow Through Inlet Manifolds of HVAC Systems
Authors: Shiva Prasad B. G. , Groshek Jacob A.
Published: September 2009

Inlet manifolds in HVAC systems are required to deliver specified amounts of refrigerant and oil to multiple compressors. However, multiphase flow through such manifolds is quite sensitive to upstream geometry and flow conditions. This paper reports a CFD investigation done to understand the sensitivity of oil flow (the minor component) in such manifolds with a T junction and 3 outlet pipes to the design of the inlet feed pipe geometry. The main objective was to understand the effect of upstream bends and settling length on the nature of flow through the outlets, particularly with reference to the delivery of the required amount of oil and refrigerant to each compressor. The results indicated that the refrigerant flow was not sensitive to upstream effects, while the oil flow was quite sensitive to distortions introduced in to the upstream flow field by lack of sufficient settling length and bends. It further showed that the sensitivity increased with oil droplet size.
Joint Optimization of Transportation and Spare Parts Inventory Policies in a Reverse Logistics Network Using OptQuest
Authors: Ilgin Mehmet A. , Gupta Surendra M.
Published: September 2009

The aim of this study is the joint optimization of the transportation and spare parts inventory policies in a reverse logistics (RL) network designed for End of Life (EOL) television (TV) recyling. Besides recycling, Printed Circuit Boards (PCBs) recovered from EOL TVs are used to meet the spare PCB demand. In order to model this RL network with its disassembly, transportation and spare parts inventory related aspects, a discrete event simulation (DES) model has been developed in detail using Arena simulation software. Next, Arena OptQuest has been used to propose optimum number and size of trucks together with the optimum reorder (s) and order quantity (Q) levels for the spare PCBs based on the minimization of total cost which includes inventory holding, PCB recovery, new PCB acquisition, truck amortization and operating costs.
Thermal Dissociation of CH4 Using a Particle-Flow Chemical Reactor Exposed to Concentrated Solar Radiation
Authors: Maag Gilles , Gutierrez Francisco Javier , Lipinski Wojciech , Steinfeld Aldo
Published: September 2009

The performance of a 5 kW particle-flow chemical reactor for the co-production of H2 and C by thermal decomposition of CH4 is investigated using concentrated solar radiation as the energy source of high-temperature process heat. The solar reactor features a directly-irradiated flow of CH4 laden with carbonaceous particles that serve the functions of radiant absorbers and nucleation sites for the heterogeneous cracking reaction. Main operational parameters are the solar power input, CH4 mass flow rate, and solid phase volume fraction. Their effect on the chemical conversion and solid products’ characteristics are examined for active carbon and carbon black laden particles. Higher particle volume fraction resulted in higher radiative absorption and enhanced kinetics.
A Study on Sustainable Energy Sources and its Conversion Systems Towards Development of an Efficient Zero Pollution Novel Air Turbine to Use as Prime-Mover to the Light Vehicle
Authors: Singh Bharat Raj , Singh Onkar
Published: September 2009

Greater use of hydrocarbon fuel has led to fast depletion of fossil fuel reserves. This has now become worldwide problem making civilization vulnerable due to paucity of fuel in future. It is also a fact that as civilization is growing the use of transport has become essential part of life. The use of large number of vehicles for transport is contributing to about 70% of total air pollution, creating environmental & ecological imbalances. About 100–150 years old transport technology is totally based on combustions causing higher rate of emission, ultimately depleting the thickness of Ozone layer and causing the global warming. Thus worldwide fast depletion of conventional energy resources necessitates the search of alternatives such as Non-Conventional Energy Sources, Renewable Energy Sources and other Direct Conversion of Energy Sources. This paper deals with study on potential of renewable energy resources and their conversion system with emphasis on development of zero pollution engine for vehicles which may lead to sustainable future.
Combined Desalination and Refrigeration Systems Driven by Low-Grade Heat
Authors: Wang Yongqing , Lior Noam
Published: September 2009

There is often a need for both water desalination and cooling (refrigeration/air-conditioning). The cooling can be used to significantly raise system efficiency by compressor inlet cooling in a dual-purpose power-generation and desalination system using gas turbines, or simply to supply refrigeration or air conditioning beside fresh water. Motivated by the good synergetic potential of energy/exergy utilization through the combination of the LiBr-H2O refrigeration unit, LiBr-H2O heat pump, and low-temperature multi-effect evaporation desalter, two combined refrigeration and water systems, ARHP-MEE (Absorption Refrigeration Heat Pump and Multi-Effect Evaporation desalter) system and ARHP-AHP-MEE (Absorption Refrigeration Heat Pump + Absorption Heat Pump + Multi-Effect Evaporation desalter) system, driven by low-grade heat were configured, modeled and analyzed in detail in the paper. Typically, driving steam with saturation pressure of 0.15–0.35 MPa and correspondingly saturation temperature of 111.4–138.9°C is applicable to run the systems. The main results are: (1) the combined systems have good synergy, with an energy saving rate of 42% in a case study of ARHP-MEE; (2) the refrigeration-heat cogenerated ARHP subsystem is the main reason for the synergy, where the coefficient of performance is around 1.6 and exergy efficiency above 60% when driven by 0.25 MPa saturated steam; (3) at the cost of a more complex configuration, the ARHP-AHP-MEE system has the ability of varying its outputs in very wide range, offering good flexibility on design and operation; (4) the ARHP-MEE system is predicted to have good economics, and its outputs can be varied in a wide range but not independently because their ratio remains almost constant. A parametric analysis was also performed for the ARHP-MEE, further improving the understanding of the system performance.
End-of-Life Decisions Using Product Life Cycle Information
Authors: Ondemir Onder , Gupta Surendra M.
Published: September 2009

The concept of disassembly-to-order (DTO) has recently become popular. The goal of DTO is to determine the optimum number of end-of-life (EOL) products to be disassembled in order to fulfill the demand for components and materials such that some desired criteria of the system are satisfied. However, the outcome of this problem is fraught with errors. This is due to the unpredictable circumstances of the EOL products which stem from many sources such as the operating environment, different usage patterns and customers upgrades. If one could get advanced information about the status of the products, it could prove to be quite invaluable in making EOL management decisions. Advanced product information consists of two types of data, viz., static and dynamic. The static data consists of the product name, the brand name, the model type, etc. The dynamic data consists of cumulative data covering the circumstances to which the product was subjected to during its useful life. Capturing these data has become an important goal of many manufacturers. Numerous technological advances and the availability of various monitoring devices, embedded in products, offer us with many product monitoring and data collection alternatives. In this paper, an integer program is developed to model and solve the DTO problem that utilizes the captured data from EOL products. A numerical example is considered to illustrate the use of this methodology.
Study of a Fuel Supply Pump With a Piezoelectric Effect for Micro Solid Oxide Fuel Cells
Authors: Ma H. K. , Huang S. H. , Chen B. R. , Huang Y. J.
Published: September 2009

A novel design for an ethanol injection system has been proposed, which consists of the fuel injector, two valves, one pump chamber, and one piezoelectric device (central vibration). The system uses a micro-diaphragm pump with a piezoelectric device for the micro solid oxide fuel cells (SOFC), which operate at a low temperature (550 to 600 °C) and are supplied by Enerage Inc. The diameters of the pump chamber are 31 mm and 23mm, and the depths of the chamber are 1 mm and 2 mm. When the piezoelectric device actuates for changing pump chamber volume, the valves will be opened/closed, and the ethanol will be delivered into SOFC system due to its pressure variation. The dimensions of the injector chamber, vibration frequencies of piezoelectric (PZT) device, input voltages, and valve thickness and shape, are used as important parameters for the performance of the novel ethanol injection system. The experimental results show that the ethanol flow rate can reach 170ml/min at a piezoelectric device frequency of 75Hz. In addition, the ethanol flow rate is higher than the water flow rate.
LNG Vaporization Using a Novel Co-Generation System
Authors: Griepentrog H. , Tsatsaronis G. , Morosuk T.
Published: September 2009

Natural gas is one of the most important primary energy sources. It is expected to account for about 30% of total electricity generation by 2020 compared with 17% in 2000. Liquefied natural gas (LNG) is expected to have a large share in this expansion of use of natural gas. In the last years the total cost of LNG technology has decreased mainly due to improvements in the liquefaction process. The paper discusses some novel, gas-turbine-based concepts for combining LNG regasification with electricity generation. A comparative exergetic evaluation of the concepts is presented.
Nanofluids: Analysis of Heat Transfer Mechanisms and Clustering
Authors: Wong Kau-Fui V. , Castillo Michael J.
Published: September 2009

This paper surveys heat transfer in nanofluids. It summarizes and analyzes the theories regarding heat transfer mechanisms in nanofluids, and discusses the effects of clustering on thermal conductivity. The heat transfer associated with conduction is presented through various experiments followed by a discussion of the theories that were developed as a result of these experiments. Relationships between thermal conductivity and various factors such as temperature, concentration, and particle size are also displayed along with a discussion on clustering and its effects on the thermal enhancement properties of nanofluids. There is a brief discussion on convection. Nanofluid convective heat transfer research may be classified by fluid conditions of laminar flow, turbulent flow, and pool boiling. The number of studies in these areas is limited, with the smallest number of studies having been reported in the last class of pool boiling. In addition, some controversy seems to exist in a couple of the publications. Owing to the limited data found in the reviewed literature, there is no definitive model presented. There is research currently being performed on the manipulation of the properties governing the thermal conductivity of nanofluids — the particle size, shape, and surface area. Other factors that affect heat transfer are the material of the nanoparticle used, particle volume concentration, and the fluid used. Although the interest in this relatively new class of fluids has generated many experimental studies around the world, there is still disagreement over several aspects of heat transfer in nanofluids, primarily concerning the actual mechanisms behind the increased thermal conductivity, and how other factors such as clustering affect the performance of the nanofluids. Although nanoparticles have greatly decreased the risks involved with the rapid settling and clustering of particles in suspension, there is still evidence of unwanted agglomeration which could cause erosion in pipes, and affect the overall conductivity of the liquid. Research is currently being conducted to determine how to minimize this unwanted grouping of particles so as to maximize the transfer of heat through the liquid. Many theories have been proposed for the problem of clustering such as adding surface treatments to the nanoparticles, modifying the methods used to disperse the nanoparticles in the base fluid, and agitating the nanofluids so as to break up any agglomerations. However, there is still no universal procedure to achieve a stable and durable suspension of particles with a low amount of agglomeration.
Analysis of Inventory Management in Reverse Supply Chain Using Stochastic Dynamic Programming Model
Authors: Johar Badr O. , Gupta Surendra M.
Published: September 2009

Reverse logistics is a critical topic that has captured the attention of government, private entities and researchers in recent years. This increase in the concern was driven by current set of government regulations, increase of public awareness, and the attractive economic opportunities. Also, environmentalists have always demanded Original Equipment Manufacturers (OEMs) to be more involved and be responsible of their products at the end of its life cycle. However, the uncertainty in quality of items returned, and its quantity discourage OEMs from participating in such programs. Because of the unique problems associated and the complex nature of the reverse logistics activities, numerous studies have been carried out in this field. One of those crucial areas is inventory management of End-of-Life (EOL) products. The take back program could possibly bring financial burden to OEM if it is not managed well. Thus, an efficient yet cost effective system should be implemented to appropriately manage the overwhelming number of returns. Previously, we have analyzed the problem based on the assumption that the number of core products returned and disassembled parts and subassemblies are known in advance. In this paper, we introduce a probabilistic approach where different quality levels of for every component disassembled are considered and different probabilities of these qualities given the quality of the returned product. The model utilizes a multi-period stochastic dynamic programming in a disassembly line context to solve the problem, and generate the best option that will maximize the system total profit. A numerical example is given to illustrate the approach. Finally, directions for future research are suggested.
Quantum Thermodynamics for the Modeling of Hydrogen Storage on a Carbon Nanotube
Authors: von Spakovsky Michael R. , Smith Charles E. , Verda Vittorio
Published: September 2009

A typical approach for modeling systems at a nanoscale in states of non-equilibrium undergoing an irreversible process is to use an ad hoc mixture of molecular dynamics (linear and nonlinear), i.e. classical mechanics, coupled to assumptions of stable equilibrium which allow one via analogy to incorporate equilibrium thermodynamic state information such as temperature and pressure into the modeling process. However, such an approach cannot describe the actual thermodynamic evolution in state which occurs in these systems since the equation of motion used (Newton’s second law) can only describe the evolution in state from one mechanical state to another. To capture the actual thermodynamic evolution, a more general equation of motion is needed. Such an equation has been proposed, i.e. the Beretta equation of motion, as part of a general theory, which unifies (not simply bridges as is the case in statistical thermodynamics) quantum mechanics and thermodynamics. It is called the unified quantum theory of mechanics and thermodynamics or quantum thermodynamics. This equation, which strictly satisfies all of the implications of the laws of thermodynamics, including the second law, as well as of quantum mechanics, describes the thermodynamic evolution in state of a system in non-equilibrium regardless of whether or not the system is in a state far from or close to stable equilibrium. This theory and its dynamical postulate are used here to model the storage of hydrogen in an isolated box modeled in 1D and 2D with a carbon atom at one end of the box in 1D and a carbon nanotube in the middle of the box in 2D. The system is prepared in a state with the hydrogen molecules initially far from stable equilibrium, after which the system is allowed to relax (evolve) to a state of stable equilibrium. The so-called energy eigenvalue problem is used to determine the energy eigenlevels and eigenstates of the system, while the nonlinear Beretta equation of motion is used to determine the evolution of the thermodynamic state of the system as well as the spatial distributions of the hydrogen molecules in time. The results of our initial simulations show in detail the trajectory of the state of the system as the hydrogen molecules, which are initially arranged to be far from the carbon atom or the carbon nanotube, are seen to spread out in the container and eventually become more concentrated near the carbon atom or atoms.
Energy Efficient Residential Thermal Control With Wireless Sensor Networks: A Case Study for Air Conditioning in California
Authors: Ota Nathan , Arens Ed , Wright Paul
Published: September 2009

Residential thermostats are sensor-limited devices, but low-cost wireless sensor network technology is enabling new spatially distributed sensing capabilities. This paper evaluates the energy and comfort performance of three multi-sensor control strategies that use wireless temperature and humidity sensors in each room and that can be applied to existing on-off residential central systems. The multi-sensor control strategies adjust the temperature set point of a thermostat to control the average of all room temperatures using a temperature threshold logic, minimize aggregate discomfort of all rooms, or maximize the number of rooms within a comfort zone. The strategies were tested using a custom wireless sensor network control system in a seven room, 2,100 square foot single-story house located in Pleasanton, CA during August and September. Performance was benchmarked against an implementation of a single-sensor constant temperature set point control logic using the custom control system and against a constant temperature set point using the original thermostat. Results show multi-sensor strategies may produce simultaneous improvements in energy consumption, room-to-room temperature distributions, and average comfort, compared to the single-sensor constant temperature set point threshold logic.
An Electromagnetic Microscale Vibration Harvester for Powering Wireless Sensor Nodes
Authors: Waterbury A. C. , Koplow M. , Wright P. K.
Published: September 2009

Most vibrational harvesting systems are resonant based systems that generate maximum power when the resonant frequency matches the fundamental mode of the ambient environment. Because microsized devices tend to have high natural frequencies, it is difficult to match the generator resonant frequency to environmentally available frequencies. This problem is addressed here by considering a multi-turned planar beam geometry for an electromagnetic resonator designed to resonant in the environmental frequency range while maintaining a small footprint on the order of 1 cm2. This work considers the application of powering wireless sensor nodes on machine tools, which are characterized by 10 m/s2 accelerations at 70Hz at the base of a 5 hp machine tool. Taking advantage of toothed iron magnetic circuit geometry, a theoretical power density of 8 mW per cubic centimeter at one g of acceleration is shown to be viable.