bluuebunny/crossref_metadata_2025 huggingface dataset:
Labor Market Policies as Instruments of Industry Policy: What Can Europe Learn from Southeast Asia?
Authors: Chowdhury Anis
Published: October 2008

Abstract.  It seems there is a pessimistic view about the need and effectiveness of industry policy in an era of unprecedented globalization. The discussion about industry policy has been mostly on the fiscal, credit, and tariff measures, which are generally designed to favor particular activities. However, the rationale for industrial policy does not have to be the infant industry argument or market failures and knowledge spillover. In advanced industrial countries, the rationale for industry policy arises from the need to constantly restructure their economies to maintain competitiveness. The lesson that mature democracies can learn from East and Southeast Asia is the importance of consensual policy making, especially in the realm of the labor market. Such policies have not only helped them maintain macroeconomic stability but also accelerated industrial restructuring.
2 Looking Beyond Gender Hierarchy: Rethinking Gender at Teotihuacan, Mexico
Authors: De Lucia Kristin
Published: October 2008

The absence of gender inequality in art and burials at Teotihuacan, Mexico, poses an interesting problem that has been largely ignored by archaeologists. Archaeologists' lack of attention to gender at Teotihuacan perhaps derives from expectations of gender hierarchies in state societies, resulting in misguided conclusions and unexplored alternative interpretations. In this chapter, I ask how eliminating assumptions about gender hierarchies might help us to gain a better understanding of social relations at Teotihuacan. By incorporating multiple lines of evidence including art, burials, and households, I argue that group identity superseded the importance of the individual, foregrounding “house” identity over gender. Social solidarity may have been particularly necessary at Teotihuacan since a large percentage of male and female residents were foreigners. While socially constructed genders may have been an important component of social identity, I suggest that it was largely an unimportant factor in determining social status.
3 Hearths, Grinding Stones, and Households: Rethinking Domestic Economy in the Andes
Authors: Goldstein Robin Coleman
Published: October 2008

This case study of Andean house remains in central Peru adopts a gendered perspective and, on the basis of archaeological evidence, challenges the normalized domestic model of “lo Andino.” Although most Andean archaeological studies equate economically independent households with independent structures, this analysis reexamines the accuracy of this convention. The presence of a grinding stone, an essential tool of an economically independent unit, varies among house structures, which suggests that multiple houses shared labor on a daily basis.
4 Breaking Down Binaries: Gender, Art, and Tools in Ancient Costa Rica
Authors: Preston‐Werner Theresa
Published: October 2008

Giant metate‐like stone sculptures, found in all regions of Costa Rica, though in various forms, continue to fascinate researchers. Archaeologists contrast these sculptures with other, more utilitarian metates in order to determine their purpose and meaning. They create two groups—metates used by women for grinding subsistence foods and elaborate metates used by men for ritual purposes. This chapter challenges the binaries of tool/art, utilitarian/elaborate, and female/male that essentialize gender and homogenize historical variability. Figurine and burial data demonstrate women's connection to elaborate metates and ritual. In addition, ceramic figurines depict flexibility in gender roles at least within the stratum of ancient Costa Rican society that they depicted. This instance of stereotyped gender attribution and the absence of attention to the possible dynamism of women's lives shows the importance of a feminist approach to archaeology and the need to draw on multiple lines of evidence to answer archaeological questions.
8 She Sells Seashells: Women and Mollusks in Huatulco, Oaxaca, Mexico
Authors: Pankonien Dawn
Published: October 2008

In this chapter, I examine seashells recovered from a 1985 archaeological study of Bahias de Huatulco, Mexico. I focus on both the primary and the secondary functions of the shells, describing their use as food, construction material, and an important dye source. I begin by discussing the shells in their local context and then later outline arguments both for and against shell trade inland. I ask, why are the shells here, and then, why these specific shells? In answering these questions, I investigate how these shells were used, the industries that they imply, and, finally, how women are necessarily implicated in processes of collection and production.
Chaperone signalling complexes in Alzheimer's disease
Authors: Koren John , Jinwal Umesh K. , Lee Daniel C. , Jones Jeffrey R. , Shults Cody L. , Johnson Amelia G. , Anderson Laura J. , Dickey Chad A.
Published: October 2008

Introduction

Chaperone regulation in Alzheimer's disease

Conclusions

Molecular chaperones and heat shock proteins (Hsp) have emerged as critical regulators of proteins associated with neurodegenerative disease pathologies. The very nature of the chaperone system, which is to maintain protein quality control, means that most nascent proteins come in contact with chaperone proteins. Thus, amyloid precursor protein (APP), members of the gamma‐secretase complex (presenilin 1 [PS1] collectively), the microtubule‐associated protein tau (MAPT) as well as a number of neuroinflammatory components are all in contact with chaperones from the moment of their production. Chaperones are often grouped together as one machine presenting abnormal or mutant proteins to the proteasome for degradation, but this is not at all the case. In fact, the chaperone family consists of more than 100 proteins in mammalian cells, and the primary role for most of these proteins is to protect clients following synthesis and during stress; only as a last resort do they facilitate protein degradation. To the best of our current knowledge, the chaperone system in eukaryotic cells revolves around the ATPase activities of Hsp70 and Hsp90, the two primary chaperone scaffolds. Other chaperones and co‐chaperones manipulate the ATPase activities of Hsp70 and Hsp90, facilitating either folding of the client or its degradation. In the case of Alzheimer's disease (AD), a number of studies have recently emerged describing the impact that these chaperones have on the proteotoxic effects of tau and amyloid‐β accumulation. Here, we present the current understandings of chaperone biology and examine the literature investigating these proteins in the context of AD.
Association of the composite IL‐1 genotype with peri‐implantitis: a systematic review
Authors: Huynh‐Ba G. , Lang N. P. , Tonetti M. S. , Zwahlen M. , Salvi G. E.
Published: October 2008

Objective: Cytokine gene polymorphisms may modulate the host response to the bacterial challenge and influence susceptibility to peri‐implantitis.

Objective: To systematically review the evidence of an association between the interleukin‐1 (IL‐1) composite genotype, i.e. presence of the allele 2 in the gene clusters IL‐1A (−889) and in IL‐1B (+3953), and peri‐implantitis.

Material and methods: An electronic search in the National Library of Medicine‐computerized bibliographic database MEDLINE and a manual search were performed. The search was conducted for longitudinal clinical trials comparing progression of peri‐implantitis in IL‐1 genotype positive (carrying allele 2) with IL‐1 genotype negative (not carrying allele 2) subjects. Selection of publications, extraction of data and validity assessment were made independently by two reviewers.

Results: The search provided 44 titles of which two longitudinal publications were included.

Conclusion: Based on the findings from this study, there is not enough evidence to support or refute an association between the IL‐1 genotype status and peri‐implantitis. Systematic genetic testing for the assessment of the risk of peri‐implantitis cannot be recommended as a standard of care at this time.
Use of immunohistochemistry in melanocytic lesions
Authors: Prieto Victor G. , Shea Christopher R.
Published: October 2008

The great majority of cutaneous melanocytic lesions can be readily classified as one of the defined diagnostic entities, either benign or malignant. Therefore, only in a minority of lesions, it is necessary to employ ancillary techniques to help in the diagnosis. The most popular and probably the most helpful of these is immunohistochemistry: an area in which Dr McNutt has made some of his most important scholarly contributions. Following Dr McNutt’s lead, in this article, we describe the use of immunohistochemistry as a diagnostic aid in dermatopathology as well as the potential pitfalls commonly encountered in practice.
The limited specificity of histological examination in the diagnosis of dysplastic nevi
Authors: Rabkin Michael S.
Published: October 2008

Dysplastic nevi were originally described as a distinct entity with specific clinical and histological features of importance as direct precursors of malignant melanoma and as markers of patients at increased risk of developing melanoma in the setting of familial melanoma. Nevi with the clinical and histological features described first as ‘B‐K moles’ and later as ‘dysplastic nevi’ clearly do exist and do sometimes represent melanoma precursors or melanoma risk markers, but it is now recognized that most dysplastic nevi never progress to melanoma, that the histological features originally described in nevi in familial melanoma patients are poorly correlated with dysplastic nevi as they are defined clinically, and that overlapping or identical histological features are found in a variety of other melanocytic lesions including small (< 5 mm) melanocytic nevi, lentiginous nevi, atypical (dysplastic) lentiginous nevi, lentiginous melanoma, lentigo maligna and nevi in an ever‐growing number of ‘special sites’. This article will briefly review the evolution of our understanding of the histological range of nevi and the histological differential diagnosis of dysplastic nevi.
Melanocytic lesions of the genital area with attention given to atypical genital nevi
Authors: Ribé Adriana
Published: October 2008

Melanocytic lesions of the genital area are rare. They arise mainly in the vulva, although they can also occur less frequently in the perineum, mons pubis and male genitalia and represent 10–12% of pigmented lesions of White women. These pigmented lesions include melanocytic nevi, lentigines, melanocytic nevi with architectural disorder and atypia of melanocytes (dysplastic nevi) and melanomas with microscopic features similar to those seen elsewhere on the body. There is a small subset of benign nevi named atypical melanocytic nevi of the genital type (AMNGT) that occur in young women, with distinctive histologic features in some cases overlapping morphologically with those of melanoma. Thus, it is important to distinguish AMNGT from melanomas in terms of prognosis and treatment. We retrieved 58 cases of genital pigmented lesions diagnosed at our hospital from 1986 to 2008 to evaluate their clinicopathologic features with especial consideration to those cases with atypical features. Thirty‐two cases (55%) were common nevi, 10 (17%) lentigines, 6 (10%) melanomas, 3 (5%) dysplastic nevi and 1 blue nevus. Six cases (10%) corresponded to AMNGT and were taken from women with a median age of 21 years. All cases showed symmetry, and the melanocytic proliferation was well demarcated at the lateral margins. The junctional component was very prominent and formed by round or fusiform nests with common retraction artifact and/or cellular dyshesion or as a single cell proliferation with mild (33%) to moderate (67%) cytologic atypia, focal pagetoid spread (17%) and a benign‐appearing dermal component (83%) with maturation and dense eosinophilic fibrosis in the superficial dermis. Neither nuclear atypia of melanocytes in the superficial dermis nor dermal mitoses were observed. AMNGT were excised, and no recurrences were recorded in the follow up (median 10.5 years). Therefore, it seems that there is no evidence that AMNGT are precursors of dysplastic nevi or melanomas.
Topical negative pressure effects on coronary blood flow in a sternal wound model
Authors: Lindstedt Sandra , Malmsjö Malin , Gesslein Bodil , Ingemansson Richard
Published: October 2008

Several studies have suggested that mediastinitis is a strong predictor for poor long‐term survival after coronary artery bypass surgery (CABG). In those studies, several conventional wound‐healing techniques were used. Previously, we have shown no difference in long‐term survival between CABG patients with topical negative pressure (TNP)‐treated mediastinitis and CABG patients without mediastinitis. The present study was designed to elucidate if TNP, applied over the myocardium, resulted in an increase of the total amount of coronary blood flow. Six pigs underwent median sternotomy. The coronary blood flow was measured, before and after the application of TNP (−50 mmHg), using coronary electromagnetic flow meter probes. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium) and after 20 minutes of LAD occlusion (ischaemic myocardium). Normal myocardium: 171·3 ± 14·5 ml/minute before to 206·3 ± 17·6 ml/minute after TNP application, P < 0·05. Ischaemic myocardium: 133·7 ± 18·4 ml/minute before to 183·2 ± 18·9 ml/minute after TNP application, P < 0·05. TNP of −50 mmHg applied over the LAD region induced a significant increase in the total coronary blood flow in both normal and ischaemic myocardium.
The pro‐inflammatory environment in recalcitrant diabetic foot wounds
Authors: Acosta Jorge Berlanga , Garcia del Barco Diana , Cibrian Vera Danay , Savigne William , Lopez‐Saura Pedro , Guillen Nieto Gerardo , Schultz Gregory S
Published: October 2008

Lower extremity ulceration is one of the serious and long‐term diabetic complications rendering a significant social burden in terms of amputation and quality‐of‐life reduction. Diabetic patients experience a substantial wound‐healing deficit. These lesions are featured by an exaggerated and prolonged inflammatory reaction with a significant impairment in local bacterial invasion control. Experimental and clinical evidences document the deleterious consequences of the wound’s pro‐inflammatory phenotype for the repair process. From a biochemical standpoint, hyperinflammation favours wound matrix degradation, thus, amplifying a pre‐existing granulation tissue productive cells’ invasiveness and recruitment deficit. Tumour necrosis factor perpetuates homing of inflammatory cells, triggers pro‐apoptotic genes and impairs reepithelialisation. Advanced glycation end‐products act in concert with inflammatory mediators and commit fibroblasts and vascular cells to apoptosis, contributing to granulation tissue demise. Therapeutic approaches aimed to downregulate hyperinflammation and/or attenuate glucolipotoxicity may assist in diabetic wound healing by dismantling downstream effectors. These medical interventions are demanded to reduce amputations in an expanding diabetic population.
Incidence of bullosis diabeticorum – a controversial cause of chronic foot ulceration
Authors: Larsen Kirsten , Jensen Tonny , Karlsmark Tonny , Holstein Per E
Published: October 2008

Bullosis diabeticorum (BD) is considered a rare and relatively harmless skin manifestation with tense blisters appearing rapidly and mostly on the feet. Most papers report only a few cases and the cause of the blisters is not known. We have experienced that the lesions are not so rare and may turn into chronic foot ulcers with complications. Retrospective study of 25 consecutive patients with 35 outbreaks and 93 bullae in a population of 5000 people with diabetes treated during a 3‐year period. The bullae were deroofed in order to examine the bulla base and treated as foot ulcers including debridement, antibiotics, bandage and protective footwear. The incidence of BD per year in the present diabetic population is 0·16%. In 29 outbreaks, there were hypoglycaemic episodes or highly varying blood glucose. Antibiotics were given in 17 of 35 episodes. Time to healing was as much as median 2·5 months (range 0·5–23 months). Two patients had minor amputations. BD should be well known to all members of diabetic foot care teams. Blood glucose control with special attention to hypoglycaemia at the time of eruption, deroofing of the bullae and foot ulcer care are recommended.
Improving patient outlook in rheumatoid arthritis: Experience with abatacept
Authors: Coughlin Mary
Published: October 2008

Purpose: To examine the importance of improving patient outlook in rheumatoid arthritis (RA) and to discuss the role of the nurse practitioner (NP) who, through the assessment of patient‐reported outcomes and in acting as an advocate for the patient with the wider healthcare team, has a crucial part to play in managing the overall well‐being of the patient. This article will draw on the clinical experience to date with abatacept, a first‐in‐class therapy that has been approved for the treatment of RA in patients with an inadequate response to either traditional disease‐modifying antirheumatic drugs (DMARDs), such as methotrexate, or biological DMARDs, such as tumor necrosis factor‐α antagonists.

Data sources: A comprehensive literature search was performed using the National Library of Medicine (MEDLINE), EMBASE, and BIOSIS databases (restricted to articles posted between January 2000 and February 2007) with the search terms CTLA‐4Ig, abatacept, and primary clinical trial publications in patients with RA. The clinical data are summarized in this review along with safety data presented in the prescribing information.

Conclusions: Recent changes in the approach to RA treatment, particularly the advent of biological therapies, have impacted the role of the NP. The role of the NP is integral to the management of RA and in maximizing patient outcomes, through educating patients to make informed choices regarding their treatment, ensuring the safe administration of therapies and monitoring response to therapy, and in acting as an advocate for the patient within the wider healthcare team.

Implications for practice: The use of more patient‐centered measures of response are gaining increasing importance both in clinical trials and in clinical practice, and as such the NP has an important role in ensuring that both the physical and the psychological needs of patients are met. Clinical trials to date have shown that abatacept provides significant and clinically meaningful improvements in patient‐reported outcomes, as well as demonstrating significant clinical benefits and a consistent safety profile, thus representing a valuable treatment option within the RA treatment armamentarium.
Second language learning in a family nurse practitioner and nurse midwifery diversity education project
Authors: Kelley Frances J. , Klopf Maria Ignacia
Published: October 2008

Purpose: To describe the Clinical Communication Program developed to integrate second language learning (L2), multimedia, Web‐based technologies, and the Internet in an advanced practice nursing education program.

Data sources: Electronic recording devices as well as audio, video editing, Web design, and programming software were used as tools for developing L2 scenarios for practice in clinical settings.

Conclusions: The Clinical Communication Program offers opportunities to support both students and faculty members to develop their linguistic and cultural competence skills to serve better their patients, in general, and their students who speak a language other than English, in particular. The program provided 24 h on‐demand access for using audio, video, and text exercises via the Internet.

Implications for practice: L2 education for healthcare providers includes linguistic (listening, speaking, reading, and writing) experiences as well as cultural competence and practices inside and outside the classroom environment as well as online and offline the Internet realm.
Docking and Quantitative Structure–Activity Relationship Studies for the Bisphenylbenzimidazole Family of Non‐Nucleoside Inhibitors of HIV‐1 Reverse Transcriptase
Authors: Lagos Carlos F. , Caballero Julio , Gonzalez‐Nilo Fernando D. , David Pessoa‐Mahana Carlos , Perez‐Acle Tomas
Published: October 2008

Molecular docking studies on a set of bisphenylbenzimidazole derivatives were conducted to identify the compounds binding orientations within the HIV‐1 reverse transcriptase non‐nucleoside binding pocket. A good correlation between the calculated binding free energies and the experimental inhibitory activities suggests that the identified binding conformations of these inhibitors are reliable. Based on obtained bisphenylbenzimidazoles binding conformations, a predictive quantitative structure–activity relationship model based on radial distribution function descriptors was developed. The obtained quantitative structure–activity relationship model was predictive according to internal and external validation experiments and might provide guidelines for the design of novel non‐nucleoside HIV‐1 reverse transcriptase inhibitors based on the 1‐benzyl‐2‐arylbenzimidazole scaffold.
Mechanistic‐Based Descriptors for QSAR Study of Psychotropic Drug Toxicity
Authors: Esteki Mahnaz , Khayamian Taghi
Published: October 2008

A quantitative structure–activity relationship model has been developed for three important classes of psychotropic drugs including phenothiazines, antidepressants and anxiolitics. Toxicity was expressed as the oral LD50values for mice. Acute toxicity of drugs correlated with a proposed descriptor based on the oxidation mechanism of bioactivation. The new descriptor was named hydrogen charge (HC) descriptor, and it is the sum of the HCs of amine moiety, carbons in the α‐position of the heteroatoms, carbonyl groups and unsaturated bonds. The results showed that the model with the descriptor of ratio of the HC over volume of the molecules, named the effective hydrogen charge (EHC) were superior to the model with the HC descriptor. Multiple linear regression was derived for the three categories of drugs separately predicting the LD50values. The linear models were found to describe the system with statistical parameters of RMSECV and RMSEP as follows: 41, 49 for phenothiazines, 111, 190 for antidepressants and 151, 276 for anxiolitics. The performance of the constructed models was examined using RMSECV (leave‐one‐out and leave‐group‐out), standard error, coefficient of determination (R2),R2cross‐validated (q2), the average chance correlation and residual error plots. Finally, the LD50for a variety of compounds, with unknown experimental values, were predicted.
RelACCS‐FP: A Structural Minimalist Approach to Fingerprint Design
Authors: Hu Ye , Lounkine Eugen , Batista José , Bajorath Jürgen
Published: October 2008

The design and evaluation of structural key‐type fingerprints is reported that consist of only 10–30 substructures isolated from randomly generated fragment populations of different classes of active compounds. To identify minimal sets of fragments that carry substantial compound class‐specific information, fragment frequency calculations are applied to guide fingerprint generation. These compound class‐directed and extremely small structural fingerprints push the design of so‐called mini‐fingerprints to the limit and are the shortest bit string fingerprints reported to date. For the application of relative frequency‐based activity class characteristic substructure fingerprints, a bit density‐dependent similarity metric is introduced that makes it possible to adjust similarity coefficients for individual compound classes and balance the recall of active compounds with database selection size. In similarity search trials, these small compound class‐directed fingerprints enrich active compounds in relatively small database selection sets and approach or exceed the performance of widely used structural fingerprints of much larger size and higher complexity.
A Novel High-Flux Solar Simulator Based on an Array of Xenon Arc Lamps: Optimization of the Ellipsoidal Reflector and Optical Configuration
Authors: Petrasch Jo¨rg , Steinfeld Aldo
Published: October 2008

The optical characteristics of a high-flux solar simulator that comprises an array of Xe-arc lamps with ellipsoidal specular reflectors of common focus is examined using the Monte Carlo ray tracing technique. The parameters varied are arc diameter, focal length, eccentricity, truncation diameter, and angular error of specular reflection. The geometrical design of the truncated ellipsoidal reflector is optimized for maximum transfer efficiency, defined as the portion of radiation intercepted by a circular target centered at the common focal point. An array of ten 15 kW Xe-arc lamps of 9 mm electrode gap and 35% electrical-to-radiant efficiency, each closed-coupled with an ellipsoidal reflector of optimum design, should be capable of delivering an average radiative power flux exceeding 5900 kW/m2 over a 6 cm-diameter circular target, with an overall transfer efficiency of 31.9%.
Central-Station Solar Hydrogen Power Plant
Authors: Kolb Gregory J. , Diver Richard B. , Siegel Nathan
Published: October 2008

Solar power towers can be used to make hydrogen on a large scale. Electrolyzers could be used to convert solar electricity produced by the power tower to hydrogen, but this process is relatively inefficient. Rather, efficiency can be much improved if solar heat is directly converted to hydrogen via a thermochemical process. In the research summarized here, the marriage of a high-temperature (∼1000 °C) power tower with a sulfuric acid/hybrid thermochemical cycle (SAHT) was studied. The concept combines a solar power tower, a solid-particle receiver, a particle thermal energy storage system, and a hybrid-sulfuric-acid cycle. The cycle is “hybrid” because it produces hydrogen with a combination of thermal input and an electrolyzer. This solar thermochemical plant is predicted to produce hydrogen at a much lower cost than a solar-electrolyzer plant of similar size. To date, only small lab-scale tests have been conducted to demonstrate the feasibility of a few of the subsystems and a key immediate issue is demonstration of flow stability within the solid-particle receiver. The paper describes the systems analysis that led to the favorable economic conclusions and discusses the future development path.
Research on the Ratio of Fixed Heating Charges to Total Heating Charges of Residential Buildings in Five Cities of North China
Authors: Fang Xiumu , Gao Lixin
Published: October 2008

The ratio of public heating losses to total heating losses is fixed for a given building. The determination of this ratio is the basis for allocating heating charges fairly and reasonably, and is also the basis for determining the ratio of fixed heating charges to total heating charges. The changing rule of the ratio of public heating losses to total heating losses of 15 residential buildings in north China was researched under different conditions, such as different energy conservation performance, different usage and different layout etc, and drew some referable conclusions.
Dual Receiver Concept for Solar Towers up to 100MW
Authors: Buck R. , Eck M. , Wittmann M.
Published: October 2008

The Dual Receiver Concept presented in this paper improves the adaptation of the central receiver to the steam cycle in a solar thermal power plant. By combination of an open volumetric air heater and a tubular evaporator the Dual-Receiver Concept profits from the advantages of these two concepts while their characteristic problems are avoided. The water is evaporated directly in the tubular steam generator, preheating and superheating is done in heat exchangers by using the hot air from the volumetric receiver (Fig. 1). This paper presents a concept study that extends previous work on the 10 MWel level (Buck et al. 2004) to a level of 100 MWel which is the expected power range of future plants. The results confirm the benefits of the new concept, resulting from higher thermal efficiency of the receiver and lower parasitic power consumption. The annual mean efficiency is increased from 13% to 16%. Advantageous are also the reduced thermal loads in the receiver components.
Cogeneration With Concentrating Photovoltaic Systems
Authors: Mittleman Gur , Kribus Abraham , Dayan Abraham
Published: October 2008

Simultaneous production of electrical and high-grade thermal energy is proposed with a Concentrating Photovoltaic/Thermal (CPVT) system operating at elevated temperature. The CPVT may operate at temperatures above 100°C and the thermal energy can drive processes such as refrigeration, desalination, and steam production. An example of CPVT with single-effect absorption cooling is investigated in detail. The results show that under a wide range of economic conditions, the combined solar cooling and power generation plant can be comparable and sometimes even significantly better than the conventional alternative.
Development of a Solar Heat Pump for Space
Authors: Ewert Michael K. , Bergeron David J.
Published: October 2008

As humans explore space, we find even greater temperature extremes than on Earth. Apollo astronauts, for example, did not stay on the moon past noon when surface temperatures soar to over 100°C. As we have on Earth, future space explorers will likely turn to mechanical heating and cooling systems to maintain comfortable living spaces. Most locations in Earth’s neighborhood have an abundant natural energy source from the sun, thus the development effort has taken a systems engineering approach and tried to optimize the heat pump and solar power source together. Earlier studies have shown that vapor compression cycle heat pumps are the most mass and power efficient for space applications. Photovoltaic (PV) cells are the most mature solar power conversion technology to provide electricity to the vapor compressor in space. Hence, these two technologies have been integrated into a solar PV vapor compression heat pump. A “ground-test unit” Solar Heat Pump designed to provide 15 kilowatts of cooling was completed in 2002 and underwent preliminary testing at SunDanzer’s previous location in Nevada. Following buildup of a heat pump testbed that will allow simulation of radiator loop temperatures on the moon or Mars, a complete system evaluation will be conducted in 2005 at the Johnson Space Center. Following that, the gravity dependent components of the system, most notably the compressor, will be analyzed and upgraded for the required gravity environment(s). A gravity-independent approach would allow NASA mission designers the most flexibility to use heat pump technology in future mission scenarios, but technical challenges may lead to machines optimized for a particular application. Design data and analysis, as well as the preliminary test results, indicate that the Solar Heat Pump will achieve very good efficiency, near 45% of Carnot efficiency, at a temperature lift of 45°C. A novel motor controller and computer control software allow the heat pump to use solar power directly from the PV array at about 400 volts direct current. These features, referred to as “PV-direct”, along with a good thermodynamic design, form a solid basis for the design of a future space-qualified Solar Heat Pump.
Features of Fabrication Technology and Properties of Wicks of Heat Pipe Receivers for Solar Dish/Stirling Systems
Authors: Baturkin Volodymyr , Zaripov Vladylen , Andraka Charles E. , Moss Timothy A.
Published: October 2008

Elaboration of robust and reliable capillary systems for solar energy heat pipe receivers is the important step for future application of this product for systems with thermal power of 30–80 kW. The paper considers a new approach to fabrication of capillary structure of heat pipe receivers on the basis of discrete metal fibers with diameter of 30 microns made of stainless steel 316L, and describes some of methods of wicks characterization as well. This technology has been demonstrated by fabrication of porous 4 mm thick wicks with bulk porosity about 0.82 applied to convex surfaces of dome-shaped receivers with radius 178 mm/height 119 mm (thermal power 36 kW) and radius 247 mm/height 173 mm (thermal power 68 kW) and for inner surface of tube with length 450 mm and diameter 73 mm (thermal power 14 kW). The distinction of the proposed technology is in the use of discrete fibers, which are felted on the curved surface in a special way and in the combination of procedures of the felt formation and their sintering to the surface (substrate material is Haynes Alloy 230). Execution of an extensive program of experimental characterization of a wick layer attached to the substrate has been developed and completed. The characterization of applied wicks determines a definition of their structural (local porosity, thickness of porous layer), mechanical (quality of wick bonding to substrate) and hydrodynamic properties (pumping diameter, one-phase and two-phase permeability). Initial estimation of wick performance was performed on the basis of methods developed at the National Technical University of Ukraine for two main modes of receiver operation — with return of sodium to a point on the dome (reflux) and without it. Prediction of receiver thermal performance, when they operate as a part of solar concentration assembly, was determined by specialized heat pipe performance software /Sandia National Laboratories, C. Andraka, 1999/.
Impact of Construction Materials in the Energy Consumption in Homes in the Caribbean
Authors: Alva Luis H. , Gonza´lez Jorge E. , Hertz John B.
Published: October 2008

This investigation presents the thermal analysis of an experimental, low energy consuming home for low-income families, located in Puerto Rico, where the prevailing climate is hot and humid. The objective of this analysis is to aid in the design of energy efficient homes, which in turn will reduce energy consumption in the Island. This investigation compares the analysis of this experimental house, specifically designed for the tropics, to a similarly sized, conventionally built low-cost home. Different construction materials are evaluated in conjunction with the use of either natural ventilation or air conditioning. The impact of natural ventilation is analyzed, with results for the inside temperature and interior heat removal presented and compared. Additional energy saving strategies are evaluated, including solar thermal energy for domestic hot water production, daylighting and the use of energy efficient lights. The annual energy consumption of the proposed experimental home is calculated and compared with the energy consumption of the conventional house. The thermal load of the house is calculated through the use of mathematical simulations of the dynamic annual cooling load using well-known software such as Energy-Plus for a TMY for San Juan, Puerto Rico. Results for the inside temperature of the experimental house, the heat loss due to natural ventilation, the cooling load when air conditioning is used, and energy consumption are presented and compared with the conventional house. Results indicate that the experimental house is 30% more energy efficient when all the energy saving strategies are considered.
Cost and Performance Solar Analysis Model for All Solar Technologies
Authors: Blair Nate , Mehos Mark , Christensen Craig , Janzou Steven
Published: October 2008

A comprehensive solar technology systems analysis model is being developed at NREL to support program planning for the U.S. Department of Energy’s Solar Energy Technologies Program (SETP). This new model will calculate the costs, finances and performance of current solar technologies including solar heat (typically solar domestic hot water), concentrating solar power, photovoltaics (PV) and solar hybrid lighting. The primary function of the model is to allow users to investigate the impact of variations in physical, cost, and financial parameters to better understand their impact on key figures of merit. Although a variety of models already exist to examine various issues with each individual technology, this model, when fully implemented in the future, will have the capability to analyze and compare different solar technologies (utility-scale PV vs. CSP for example) within the same interface while making use of similar cost and financing assumptions. A central idea for this model is to have a user-friendly interface while at the same time having a detailed, accurate analysis for each of the technologies. The underlying performance engine, which is hidden from the user, is TRNSYS, which already contains an extensive library of solar technology models. There are built-in cost models or the user can access their own spreadsheet-based cost model. The financial model is an extension of an existing validated finance model. This paper will discuss the goals and implementation of the model and present several sample results for interesting sensitivities.
Bayesian and Sensitivity Analysis Approaches to Modelling the Direct Solar Irradiance
Authors: Lauret Philippe , David Mathieu , Fock Eric , Adelard Laetitia
Published: October 2008

In this paper, emphasis is put on the design of a neural network to model the direct solar irradiance. Since unfortunately a neural network (NN) is not a statistician in-a-box, building a NN for a particular problem is a non trivial task. As a consequence, we argue that in order to properly model the direct solar irradiance, a systematic methodology must be employed. For this purpose, we propose a two-step approach to building the NN model. The first step deals with a probabilistic interpretation of the NN learning by using Bayesian techniques. The Bayesian approach to modelling offers significant advantages over the classical NN learning process. Among others, one can cite a) automatic complexity control of the NN using all the available data b) selection of the most important input variables. The second step consists in using a new sensitivity analysis-based pruning method in order to infer the optimal NN structure. We show that the combination of the two approaches makes the practical implementation of the Bayesian techniques more reliable.
Energy Demand, Availability in Nepal and Present PV Cost Analysis
Authors: Ghimire Dilip C. , Adhikari Sudip , Adhikary Sunil , Uchida Hideo , Umeno Masayoshi
Published: October 2008

This paper describes the Photovoltaic solar electricity generating capacity in Nepal. Although Nepal is rich in hydropower, currently only about 17% of the total population has access of electricity. The majority of the population who are living in the rural mountainous parts of Nepal is still deprived of electricity. The relatively high insulation throughout the year and geographical situation encourage for the development of PV energy in the country. The monthly mean solar radiation analysis shows that April and January receive the highest and the lowest solar radiation respectively. The PV installation rate has increased dramatically in the last five years due to relative decrease in PV module cost and government subsidy. PV technology is reliable because of its simplicity, extremely low maintenance cost and point-of-use installation possibility. The widespread use of PV will help to reduce CO2 emission and consequently contributes towards better environment.
Operation and Maintenance Field Experience With Photovoltaic Water Pumping Systems
Authors: Moore Larry , Post Hal , Adams Krista , Malczynski Len , Hauck Randy , Jesperson Tom , Skinner Rolland , Anderson Jerry
Published: October 2008

This paper presents an assessment of the failure modes, operation and maintenance (O&M) costs, and system lifecycle costs for 77 photovoltaic (PV) water pumping systems installed during a fourteen year period from 1990 to 2004. These systems were supplied, installed, operated and maintained through a customer lease program by two rural utilities, Northwest Rural Public Power District in Nebraska and Verendrye Electric Cooperative in North Dakota. Field records have been tracked and analyzed to capture maintenance events, component failure experience, repair/replacement costs and installation cost histories. The results of these analyses including annual O&M cost, failure rates, and economic comparisons with grid extension options are presented and discussed.
Passive Heat Exchanger Anti-Fouling for Solar DHW Systems
Authors: Harrison Stephen J.
Published: October 2008

The interior surfaces of heat exchangers used in domestic hot water systems are particularly prone to fouling or complete blockage due to the accumulation of sediments, scale and mineral deposits. In many locations, mineral salts and other impurities may be present in the potable water supply and fouling may occur if the heat exchanger is not routinely cleaned or flushed of accumulated matter. In small residential installations, however, this is not practical due to the associated costs. In response to this need, a passive back-flushing system was designed that allows heat exchangers to be routinely back-flushed many times a day. The action is a normal operation of the system and does not require user intervention, external power or controls to function. During back-flushing mineral deposits are washed out of the heat exchanger and flushed from the system. the operation of the device and documents the results of accelerated tests undertaken to verify its operation.
Some Environmental Considerations of Electrical Power Generation From Ocean Currents in the Straits of Florida
Authors: Finkl Charles W. , Charlier Roger , Hague Erin
Published: October 2008

Ocean currents contain a remarkable amount of kinetic energy and have potential worldwide capability. Initial tests to harness current power focus on the Straits of Florida where the Florida Current has a total flow capacity of about 30 × 106 m3 s−1. Generation of clean electricity from ocean currents off southeast Florida is based on a power extractor comprised by open-center turbine technology. This innovative turbine provides safe passage for fish and other aquatic species. The water-column array of energy production units (EPUs) will have a 350 km2 footprint, based on a 600 m (10 rotor diameters) downstream separation distance between EPUs with a lateral separation of 400 m. Water depths for the EPU field are in the range of 100 to 500 m. With such a large area of water column and benthic habitat utilized, environmental concerns must be overcome, including routing of transmission lines to shore. Risks and vulnerabilities of the proposed ocean current generated electricity include failure of individual EPUs and damage to sensitive coastal marine environments during installation.
Marine Winds Energy on the Forefront of Development
Authors: Thys Alexandre C. , Charlier Roger H.
Published: October 2008

Not so many decades ago any proposal to capture the energy of marine winds would have been met with condescending smiles and the conviction that if even such electricity source would be put to use it would be on at best a pilot scale. Really thoughts of large installations were just one of those far-fetched engineers’ dreams best relegated to the pages of scientific periodicals. Yet, of all the marine sources of energy harnessed to produce electricity, wind power is among the leaders. This paper will consider the wind farms established off and on shore; the largest projects have been implanted in the Scandinavian countries though their southern neighbors, particularly Germany and The Netherlands are displaying a solid determination to use marine winds for electricity generation. The technology exists, the environmental nuisance is benign if sites are carefully selected. But detractors still exist and they object to aesthetic damage that, they claim, is brought about. Implementation is occasionally stymied for judiciary and/or political reasons; the case of Belgium is used as an example.
Nanoporous Energy Absorption Systems
Authors: Qiao Yu , Kong Xinguo , Surani Falgun B.
Published: October 2008

In a system consisting of hydrophobic nanoporous materials immersed in water, as the pressure increases the water can be forced into the nanopores, accompanied by a large increase in system free energy. As the pressure is reduced, however, in some nanoporous materials the defiltration is difficult and thus the excess solid-liquid interface energy can be regarded as being absorbed. Due to the ultrahigh surface area of the nanoporous material, the energy absorption efficiency of this system can be higher than that of conventional protection materials by orders of magnitude. This phenomenon has great potential in developing advanced energy absorption and damping systems such as soldier armors, protection layers, blast resistant containers, etc.
The Local Instabilities of Nanostructures
Authors: Zhang Liang , Lu Jia
Published: October 2008

In this paper we discuss an atomic-scale instability condition for detecting the local elastic limit in nanoscale systems. Without resorting to the continuum stability theory, we formulate an “atomic acoustic tensor” and use the singularity condition as an indicator to inspect local instabilities of the nanoscale structure. The derivation does not depend on the pristine lattice, thus, the indicator suits for not only perfect crystals but also defective media. To validate the applicability of this new quantity, we have performed local instability analysis on carbon nanotubes under axial tension. It is found that the criterion can characterize bond-breaking related instability in both perfect and defective nanotubes.
Computational Modelling of Vibration Damping Effects in Nanoscale-Reinforced Materials
Authors: Bochkareva L. , Kireitseu M. V. , Kompis V.
Published: October 2008

A novel concept of nanoparticle vibration damping [1, 2] shows the effect that molecule-level mechanism can have on the damping and that nanoparticles/fibres/tubes-reinforced materials can provide enhanced strength and vibration damping properties. It is particularly worth noting that carbon nanotubes and spider silk can act as a simple nanoscale spring. The mechanisms involved in such materials need to be understood and the relevance to damping identified.
Propose and Characteristics Study of a New Actuation Method for Micropumps, Using Membrane Buckling
Authors: Saghafi Mohammad H. , Ahmadian Mohammad T. , Salehi Hadi , Monazami R. , Zade Azad Q.
Published: October 2008

In this paper, we present a novel idea on actuation system in micropumps. The prominent goal of this paper is to propose and prove a mechanical actuation system which works in high frequency and has good ability in producing flow and pressure in micro actuation system. As like as other common micropumps, the proposed scheme is consisted of two check valves and an actuation space. The actuation space includes a volume of liquid in a chamber and a cylindrical membrane as the actuator. The main aspect of this idea is employment of buckling as a consequence of incensement of its internal pressure caused by temperature rising in the membrane. Rise of temperature is done by passing a controllable current through the membrane and it looses its temperature to its outer space in the chamber. Frequency and amperage of the current are the elements identifying the temperatures membrane vacillates between them. Meanwhile, a nice idea is setting these values in such a way that minimum temperature of the membrane becomes equal to the temperature which membrane starts buckling at. Thermal, elastic and thermoelastic equations of the membrane and fluids dynamic equations is obtained and studied. Using these equations, the validity of the scheme is proved by showing its ability of getting and loosing temperature and also fatigue resistance of the membrane, in high frequencies. The analytical proof is done for a specific design. In the proposed design, Aluminum 1100 is adopted as membrane material and thickness and radius of the membrane are 1 μm and 100 μm, respectively. Maximum flow rate and frequency of the system according to highest temperature of the membrane are depicted in diagrams. According to this design, maximum flow rate in rational frequency and amperage of the current is 8.25 μL/min. Maximum pressure in that design is 3.5Kpa.