bluuebunny/crossref_metadata_2025 huggingface dataset:
Transfusion‐related Epstein‐Barr virus infection among stem cell transplant recipients: a retrospective cohort study in children
Authors: Trottier Helen , Buteau Chantal , Robitaille Nancy , Duval Michel , Tucci Marisa , Lacroix Jacques , Alfieri Caroline
Published: March 2012

BACKGROUND: Blood safety warrants strict screening measures to minimize the risk of transmitting blood‐borne pathogens. However, transfusion‐transmitted infections for which testing is not currently performed continue to be a concern. Among these untested agents is Epstein‐Barr virus (EBV) which, in the transplant setting, is associated with lymphoproliferative disease, a potentially fatal cancer. The aim of this study was to analyze the incidence of posttransplant EBV infection and its association with administration of blood products in children receiving a hematopoietic stem cell (HSC) graft.

STUDY DESIGN AND METHODS: This retrospective cohort study sought to review charts of pediatric recipients of HSC grafts to collect information on the presence of EBV antibodies in the recipients' pretransplant sera and in HSC donor sera, incidence of posttransplant EBV infection, and patients' transfusion history. Cumulative incidence of posttransplant EBV infection was estimated by Kaplan‐Meier methods according to pretransplant serology. The association between blood products and EBV infection was measured by Cox regression models.

RESULTS: The pretransplant EBV seroprevalence was 77.9% for recipients and 61.8% for graft donors. Virtually, all recipients received blood products during the peritransplant period. Among seronegative recipients, the 30‐ and 60‐day cumulative incidences of posttransplant EBV infection were 4.6 (95% confidence interval [CI], 1.2‐17.3) and 13.4% (95% CI, 5.8%‐29.4%), respectively. The 60‐day cumulative incidence was 8.3% (95% CI, 2.2%‐29.4%) when restricting the analysis to seronegative recipients of cord blood grafts. Importantly, there was a clear positive trend associating EBV infection to transfusion volume.

CONCLUSION: This study suggests an association between transfusions and posttransplant EBV infection in HSC transplant recipients.
Understanding Competencies in Platform‐Based Product Development: Antecedents and Outcomes
Authors: Chai Kah‐Hin , Wang Qi , Song Michael , Halman Johannes I. M. , Brombacher Aarnout C.
Published: March 2012

While previous studies have shed light on the benefits and antecedents of platform‐based product development, there is still much to be learned on the subject, particularly through an empirical approach. Based on the literature, this study proposes the concept of product platform competency and identifies four antecedents related to the development process, knowledge sharing, and the organization of development. The study hypothesizes that such competency directly affects the performance of platform‐based product development. To test these hypotheses, a large‐scale survey was conducted in theUnitedStates with 242 firms. The study found empirical evidence to support the existence of the concept of product platform competency, which comprises the reusability of subsystems, the compatibility of subsystem interfaces, and the extensibility of platform‐based products. The results show that a formalized development process, knowledge sharing across platform‐based products, continuity of platform‐based product development teams, and the existence of a champion in platform‐based product development will significantly enhance product platform competency. More interestingly, the results show that factors which have a significant effect on platform development cost are statistically different from those that have a significant effect on platform development time. For example, while formalized product development process and continuity of development team play a very significant role in shortening development time, they are less crucial in reducing development costs. In contrast, the presence of a product champion is a significant factor in achieving cost efficiency, but it has relatively lower impact on development time. Knowledge sharing was found to affect both development time and cost. In sum, this study makes three main contributions to the existing literature. The first contribution is the empirical‐tested concept of product platform competence based on key elements suggested byRobertson andUlrich. The second contribution is the development of constructs specifically for platform development based on previous studies. Relating to this is the third contribution: the development and validation of measurement items related to key drivers to platform development, the three aspects of platform development competence, and the performance measurements. These measurement items can be used by practitioners as guidelines to identify areas for improvement as well as the level of capability in platform development.
Oxide Ion Transport in Donor‐Doped Pb(ZrxTi1−x)O3: Near‐Surface Diffusion Properties
Authors: Frömling Till , Hutter Herbert , Fleig Jürgen
Published: March 2012

Oxide ion transport in Pb(ZrxTi1–x)O3 (PZT) was investigated using 18O tracer diffusion and time‐of‐flight secondary ion mass spectrometry analysis. Particularly diffusion in the near‐surface regions (a few 100 nm in depth) is discussed and strong evidence for a space charge layer near the surface is provided. In this layer, an enrichment of oxygen vacancies is found at temperatures up to 600°C, resulting in box‐shaped tracer diffusion profiles. At 650°C, however, the profile shape is modified and reveals a depletion of oxygen vacancies close to the surface. Accordingly, a change in the polarity of the surface charge takes place between 600°C and 650°C. The tracer diffusion profiles are very sensitive to surface modification, caused by etching or annealing at higher temperature, and also depend on the sintering procedure. Moreover, application of an external field during the tracer experiments affected the tracer diffusion at the cathode, while leaving the profile at the anode unperturbed. Quantitative analysis of the profiles was performed by means of numerical calculations based on Gouy‐Chapman or Mott‐Schottky space charge models. Estimates of the oxygen vacancy concentration and ionic transference number of donor‐doped PZT are provided.
Nuevas normas de la OIT sobre trabajo decente para los trabajadores domésticos
Authors: Tomei Manuela , Belser Patrick
Published: March 2012

Hay millones de trabajadores domésticos en el mundo, la mayoría de los cuales carecen de protección laboral porque sirven en hogares privados sujetos a relaciones de trabajo singulares. Están desamparados frente a la explotación, los abusos y la violencia, y realizan a menudo mucho trabajo por poco salario. El Convenio sobre las trabajadoras y los trabajadores domésticos (núm. 189) y su Recomendación complementaria (núm. 201), adoptados en junio de 2011 por la OIT, encarnan la determinación de gobiernos y organizaciones de empleadores y de trabajadores de todo el mundo de remediar esta situación. Los autores del artículo, que participaron en los preparativos y negociaciones que alumbraron estas normas, estudian el contenido y los puntos polémicos de las mismas.
A Rab11A/Myosin Vb/Rab11‐FIP2 Complex Frames Two Late Recycling Steps of Langerin from the ERC to the Plasma Membrane
Authors: Gidon Alexandre , Bardin Sabine , Cinquin Bertrand , Boulanger Jerome , Waharte François , Heliot Laurent , de la Salle Henri , Hanau Daniel , Kervrann Charles , Goud Bruno , Salamero Jean
Published: March 2012

A large body of knowledge relating to the constitution of Rab GTPase/Rab effector complexes and their impact on both membrane domain organization and overall membrane trafficking has been built up in recent years. However in the context of the live cell there are still many questions that remain to be answered, such as where and when these complexes assemble and where they perform their primary function(s). We describe here the dynamic processes that take place in the final steps of the Rab11A dependent recycling pathway, in the context of the membrane platform constituted by Myosin Vb, Rab11A, and Rab11‐FIP2. We first confirm that a series of previously reported observations obtained during the study of a number of trafficking cargoes also apply to langerin. Langerin is a cargo molecule that traffics through Rab11A‐positive membrane domains of the endosomal recycling pathway. In order to explore the relative dynamics of this set of partners, we make extensive use of a combinatory approach of Live‐FRET, fast FRAP video, fast confocal and TIRF microscopy modalities. Our data show that the Myosin Vb/Rab11A/Rab11‐FIP2 platform is spatially involved in the regulation of langerin trafficking at two distinct sites within live cells, first at the sorting site in the endosomal recycling compartment (ERC) where transport vesicles are formed, and subsequently, in a strict time‐defined order, at the very late stage of docking/tethering and fusion of these langerin recycling vesicles to the plasma membrane.
The In Vivo Dynamic Organization of BRCA1‐A Complex Proteins at DNA Damage‐Induced Nuclear Foci
Authors: Mok Myth T.S. , Henderson Beric R.
Published: March 2012

The breast cancer associated gene 1 (BRCA1)‐A protein complex assembles at DNA damage‐induced nuclear foci to facilitate repair of double‐stranded breaks. Here, we describe the first systematic comparison of the dynamics, copy number and organization of its core components at foci. We show that the protein pools at individual foci generally comprise a small immobile fraction (∼20%) and larger mobile fraction (∼80%), which together occupy the same focal space but exist at different densities. In the mobile fraction, Abraxas (CCDC98) and the heterodimer BARD1–BRCA1 share similar rates of dynamic exchange (complete turnover in ∼500 seconds). In contrast, RAP80, which is required for initial foci assembly, was more dynamic with 25‐fold faster turnover at mature foci. In addition, Abraxas, BARD1, BRCA1 and Merit40 (NBA1) were stably retained in the immobile fraction of foci under conditions causing loss of BRCC36 and RAP80, suggesting a shift to RAP80‐independent localization after foci formation. These results, combined with our finding that RAP80 (∼1200 copies per focus) is twofold more abundant than Abraxas/BARD1/BRCA1 at foci, suggest new models defining the dynamic organization of BRCA1‐A complex at mature foci, wherein the unusually fast turnover of RAP80 may contribute to its regulation of BRCA1‐dependent DNA repair.
The response of PKD1L3 / PKD2L1 to acid stimuli is inhibited by capsaicin and its pungent analogs
Authors: Ishii Sho , Kurokawa Azusa , Kishi Mikiya , Yamagami Keigo , Okada Shinji , Ishimaru Yoshiro , Misaka Takumi
Published: March 2012

Polycystic kidney disease (PKD) 2L1 protein is a member of the transient receptor potential (TRP) ion channel family. In circumvallate and foliate papillae, PKD2L1 is coexpressed with PKD1L3. PKD2L1 and PKD1L3 interact through their transmembrane domain and the resulting heteromer PKD1L3/PKD2L1 owns a unique channel property called ‘off‐responses’ to acid stimulation, although PKD2L1 does not own this property by itself. To define the pharmacological properties of the PKD1L3/PKD2L1 channel, we developed a new method to effectively evaluate channel activity using human embryonic kidney 293T cells in which the channel was heterologously expressed. This method was applied to screen substances that potentially regulate it. We found that capsaicin and its analogs, which are TRPV1 agonists, inhibited the response to acid stimuli and that the capsaicin inhibition was reversible with an IC50 of 32.5 μm. Capsaicin and its analogs are thus useful tools for physiological analysis of PKD1L3/PKD2L1 function.

Database
 Nucleotide sequence data are available in the GenBank database under the accession numbers hTRPA1, BC148423 and hTRPV3, BC104866
Trends in Australian human resource management: what next?
Authors: Kramar Robin
Published: March 2012

This article examines the trends in Australian human resource management (HRM) policies in the last fifty years. It briefly reports on the practices used in the period from the 1960s to the early 1990s and provides a brief description of the characteristics of the concept of strategic human resource management (SHRM). The article then examines the results of four surveys co‐ordinated by the Cranet Network and conducted in Australia between 1996 and 2008–09. These surveys show there have been strong trends of HRM policies becoming more calculative and individual, a reduction in the role of collective organisations, the adoption of some HRM policies regarded as more effective than others and the development of the roles of HRM managers and HRM departments. There was increasing use of flexible working practices, greater use of performance appraisals, the development of policies such as career planning methods, career break schemes and targeting older workers and women. The representation of human resource managers on boards increased between 1996 and 2008–09.
Talent management: challenges of building cross‐functional capability in high‐performance work systems environments
Authors: Levenson Alec
Published: March 2012

Occupational dissimilarity is a measure of the overlap in education, skills and experience across two disciplines. Though occupational dissimilarity is not directly addressed in the organization design, careers, and other literatures, it plays an important role in organizational effectiveness. Specifically, integrating tasks when occupations are dissimilar is quite difficult, which can hinder successful strategy execution. When two or more dissimilar functions play key roles in the value‐creation process (for example, R&D and sales), the risks to organizational effectiveness are particularly acute. In these cases there are no natural tendencies for individuals to develop cross‐functional skills, and traditional integration approaches typically include only formal mechanisms such as general manager development and cross‐functional teams. The argument is made here that organizations should more actively focus on ways to foster cross‐functional skills at the individual contributor level, not just general manager level, in such cases. Examples from logistics, consumer product analytics, and services procurement/business process outsourcing are addressed. Implications for organizations operating in emerging markets with large consumer markets but underdeveloped talent markets are also explored.
Lipofuscin and A2E Accumulate with Age in the Retinal Pigment Epithelium of Nrl−/− Mice†
Authors: Boyer Nicholas P. , Tang Peter H. , Higbee Daniel , Ablonczy Zsolt , Crouch Rosalie K. , Koutalos Yiannis
Published: March 2012

Lipofuscin is a fluorescent material with significant phototoxic potential that accumulates with age in the retinal pigment epithelium (RPE) of the eye. It is thought to be a factor in retinal degeneration diseases. The most extensively characterized lipofuscin component, N‐retinylidene‐N‐retinylethanolamine (A2E), has been proposed to be a byproduct of reactions involving the visual pigment chromophore. To examine the impact of the visual pigment and photoreceptor cell type on lipofuscin accumulation, we analyzed the RPE from Nrl−/− mice of various ages for lipofuscin fluorescence and A2E levels. The photoreceptor cells of the Nrl−/− retina contain only cone‐like pigments, and produce cone‐like responses to photostimulation. The cone‐like nature of these cells was confirmed by the presence of RPE65. Lipofuscin was measured with fluorescence imaging, whereas A2E was quantified by UV/VIS absorbance spectroscopy coupled to HPLC. The identity of A2E was corroborated with tandem mass spectrometry. Lipofuscin and A2E accumulated with age, albeit to lower levels compared with wild type mice. The emission spectra of RPE lipofuscin granules from Nrl−/− mice were similar to those from wild type mice, with λmaxca 610 nm. These results demonstrate that cone visual pigments can contribute to the production of lipofuscin and A2E.
Das Abschneiden beitragsabhängiger und steuerfinanzierter Rentenprogramme der sozialen Sicherheit in Zentralamerika und die Auswirkungen der globalen Krise
Authors: Mesa‐Lago Carmelo
Published: March 2012

Auszug

In den letzten 30 Jahren war Lateinamerika Vorreiter bei strukturellen Rentenreformen. Dieser Artikel betrachtet eine repräsentative regionale Auswahl von sieben Staaten Zentralamerikas mit unterschiedlichen Entwicklungsniveaus (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua und Panama) und untersucht beitragsabhängige und steuerfinanzierte Renten sowie jüngste Rentenreformen. Er vergleicht das Abschneiden der Systeme nach fünf Prinzipien der sozialen Sicherheit: Einheitlichkeit; universeller Deckung; Angemessenheit der Leistungen; gleicher Behandlung, Solidarität und Geschlechterneutralität sowie finanzieller Tragfähigkeit. Auch die Auswirkungen der globalen Krise auf die untersuchten Rentensysteme werden analysiert, wobei zwischen öffentlichen und privaten Renten unterschieden wird. Zum Schluss werden Lehren daraus gezogen und Strategien für die Zukunft vorgeschlagen.
Die Wirksamkeit des garantierten Mindesteinkommens in Luxemburg
Authors: Amétépé Fofo
Published: March 2012

Auszug

Dieser Artikel analysiert die Wirksamkeit des garantierten Mindesteinkommens (Revenu Minimum Garanti, RMG) in Luxemburg, ausgehend von den Daten aus dem Jahr 2007. Zur Ermittlung der Wirksamkeit dieser Hilfsleistung zählen wir zunächst die anspruchsberechtigten Haushalte im Jahr 2007 einmal nach den Kriterien von 2007 und einmal nach den Kriterien von 1986 . Es zeigt sich, dass nach den Kriterien von 2007 5,5 Prozent der Haushalte bezugsberechtigt sind, während es nach den Kriterien von 1986 nur 3,75 Prozent gewesen wären. Dies belegt, dass durch die Ausweitung der Berechtigungskriterien mehr von Armut betroffene Haushalte erreicht werden. Anschließend analysiert der Artikel die Wirksamkeit unter einem anderen Aspekt, nämlich demjenigen der Nichtinanspruchnahme im Jahr 2007. Zwei Drittel der bezugsberechtigten Haushalte haben das RMG nicht in Anspruch genommen. Regressionsanalysen der möglichen Faktoren der Nichtinanspruchnahme haben die häufig in der Literatur angeführten Hypothesen bestätigt: So spielen einerseits der finanzielle Aspekt, also der nutzbare Nettowert der Unterstützung, und andererseits die Stigmatisierung, die mit der Inanspruchnahme einhergeht, eine wesentliche Rolle bei der Nichtinanspruchnahme des RMG.
Reformas del financiamiento de los sistemas de seguro de enfermedad en Alemania, Francia y Países Bajos: ¿cuáles son las consecuencias para la cobertura social y la redistribución?
Authors: Turquet Pascale
Published: March 2012

Hace ya varios años que los sistemas de seguro de enfermedad de Alemania, Francia y Países Bajos se esfuerzan por frenar sus gastos y diversificar sus recursos, inicialmente compuestos en su mayor parte por cotizaciones sociales. La diversificación se lleva a cabo mediante una ampliación de la gama de financiamientos públicos y un mayor recurso a soluciones y operadores privados. En Alemania y Países Bajos las reformas denotan la voluntad de crear una situación de competencia entre aseguradores. En Francia el seguro complementario privado se ha vuelto indispensable para disponer de un acceso abierto a la atención médica completa. Sin embargo, pese a los dispositivos correctivos de asistencia, las medidas adoptadas se repercuten en la redistribución.
An unusual manifestation of florid cemento‐osseous dysplasia: a case report
Authors: Mahdmina A. , King S. , Mellor A. , Coulthard P.
Published: March 2012

Cemento‐osseous dysplasia is a relatively uncommon condition of the jaws with a variety of presentations. This case report describes an unusual manifestation of cemento‐osseous dysplasia and aims to raise awareness of the condition among clinicians so that the correct diagnosis can be made in order to carry out the appropriate management.
Adjunctive use of tetracycline fibers with nonsurgical periodontal therapy in an adult with Down syndrome: a case report
Authors: Gautami Penmetsa Subadhra , Ramaraju Alluri Venkata , GunaShekhar Madiraju
Published: March 2012

Individuals with Down syndrome (DS) are susceptible to severe periodontal disease, due to immune alterations related to functional defects of polymorphonuclear leukocytes and monocytes. The adjunctive use of locally delivered antimicrobials has been proven to be beneficial, especially in areas where mechanical therapy might fail. This article describes the management of a patient with DS who had aggressive periodontitis. The treatment used a local drug delivery system with tetracycline fibers as an adjunct to scaling and root planing.
Photosynthetic activity and community shifts of microphytobenthos covered by green macroalgae
Authors: García‐Robledo Emilio , Corzo Alfonso , Papaspyrou Sokratis , Morris Edward P.
Published: March 2012

Macroalgae blooms, a frequent consequence of eutrophication in coastal areas, affect the photosynthetic activity of sediments dominated by microphytobenthos (MPB). Light spectra, steady‐state (after 1 h) microprofiles of O2, gross photosynthesis (Pg), community respiration in light (RL) and net community photosynthesis (Pn) were measured in diatom‐ and cyanobacteria‐dominated communities below increasing layers of Ulva. Photosynthetic photon flux (PPF) decreased exponentially with increasing layers of algae and the light spectrum was increasingly enriched in the green and deprived in blue and red regions. Sediment Pg, Pn and RL decreased as the number of Ulva layers increased; however, 1.6 times higher macroalgal density was necessary to fully inhibit cyanobacteria Pg compared with diatoms, indicating that cyanobacteria were better adapted to this light environment. Long‐term (3 weeks) incubations of diatom‐dominated sediments below increasing layers of Ulva resulted in a shift in the taxonomic composition of the MPB towards cyanobacteria. Hence, changes in the light climate below macroalgal accumulations can negatively affect the photosynthetic activity of sediments. However, spectral niche differentiation of MPB taxonomic groups and concurrent changes in the MPB community may provide sediments with increased resilience to the detrimental effects of eutrophication.
Ultrasonographic examination of the palmar aspect of the pastern of the horse: Digital flexor tendons and digital sheath
Authors: Coudry V. , Denoix J.‐M.
Published: March 2012

Ultrasonography is the technique of choice to identify and document tendon and ligament injuries and its interest in the diagnosis of pastern injuries has been largely demonstrated. Ultrasound examination is therefore part of routine examination in diagnostic work‐up of lameness originating from the foot or pastern area. This paper describes the ultrasonographic technique and presents normal and abnormal ultrasound images of the palmar pastern. A comprehensive description of normal transverse and longitudinal ultrasound scans is made at 4 anatomical levels. Main ultrasonographic findings indicative of digital flexor tendon lesions are presented as well as digital sheath injuries.
New insights into an old debate: Investigating the temporal sequence of commitment and performance at the business unit level
Authors: Winkler Silvan , König Cornelius J. , Kleinmann Martin
Published: March 2012

Job attitudes and performance are correlated, but which comes first? Despite a long‐lasting debate regarding this question, the potential ordering of the job attitude–job performance relationship and its ideal timing of measurement over time remains unclear. Based on the hedonic treadmill theory and the endowment/contrast model, we develop arguments as to why the influence of performance on subsequent attitudes might be less persistent over time than vice versa and we suggest a strategy to determine the ideal period for measurement time lags. We contrasted both temporal directions within a data set of 755 employees from the retail banking division of a large bank, nested in 34 business units, for the period of 2005–2008, allowing for a controlled environment and consistent data capturing over time. We studied the relationship of organizational commitment aggregated to the business unit level with two business unit performance indicators (financial achievement and customer satisfaction). Results indicated that organizational commitment had a more persistent influence on performance at the business unit level than vice versa. Consistent with prior research, this suggests that job attitudes may come first, and that practitioners might be well advised to aim to improve job attitudes in order to boost performance.

Practitioner Points

Our study suggests a potential answer to the chicken‐and‐egg problem (i.e., the temporal ordering of the job attitude–job performance relationship): Our theory and data suggest that the influence of performance on subsequent attitudes might be less persistent over time than vice versa.

Our study sheds new light onto which timely dimensions are involved in the job attitude–job performance relationship: While the impact of performance on attitudes diminishes after 1 year, the impact of attitudes on performance lasts up to 3 years.

Our results may be relevant for practitioners when it comes to evaluating the benefits of human resource initiatives and adding dollar values to the discussion around attitudinal changes.
Fluid Structure Interaction With Contact Surface Methodology for Evaluation of Endovascular Carotid Implants for Drug-Resistant Hypertension Treatment
Authors: Peter Dinesh A. , Alemu Yared , Xenos Michalis , Weisberg Ori , Avneri Itzhak , Eshkol Moshe , Oren Tal , Elazar Moshe , Assaf Yaron , Bluestein Danny
Published: March 2012

Drug-resistant hypertensive patients may be treated by mechanical stimulation of stretch-sensitive baroreceptors located in the sinus of carotid arteries. To evaluate the efficacy of endovascular devices to stretch the carotid sinus such that the induced strain might trigger baroreceptors to increase action potential firing rate and thereby reduce systemic blood pressure, numerical simulations were conducted of devices deployed in subject-specific carotid models. Two models were chosen—a typical physiologic carotid and a diminutive atypical physiologic model representing a clinically worst case scenario—to evaluate the effects of device deployment in normal and extreme cases, respectively. Based on the anatomical dimensions of the carotids, two different device sizes were chosen out of five total device sizes available. A fluid structure interaction (FSI) simulation methodology with contact surface between the device and the arterial wall was implemented for resolving the stresses and strains induced by device deployment. Results indicate that device deployment in the carotid sinus of the physiologic model induces an increase of 2.5% and 7.5% in circumferential and longitudinal wall stretch, respectively, and a maximum of 54% increase in von Mises arterial stress at the sinus wall baroreceptor region. The second device, deployed in the diminutive carotid model, induces an increase of 6% in both circumferential and longitudinal stretch and a 50% maximum increase in von Mises stress at the sinus wall baroreceptor region. Device deployment has a minimal effect on blood-flow patterns, indicating that it does not adversely affect carotid bifurcation hemodynamics in the physiologic model. In the smaller carotid model, deployment of the device lowers wall shear stress at sinus by 16% while accelerating flow entering the external carotid artery branch. Our FSI simulations of carotid arteries with deployed device show that the device induces localized increase in wall stretch at the sinus, suggesting that this will activate baroreceptors and subsequently may control hypertension in drug-resistant hypertensive patients, with no consequential deleterious effects on the carotid sinus hemodynamics.
Modeling of U.S. Corn Ethanol Industrial Growth
Authors: Kibira Deogratias , Shao Guodong
Published: March 2012

The production capacity of corn ethanol as a transportation fuel is experiencing rapid growth in the United States. The demand is driven by increased prices of gasoline, government mandates, incentives, desire for cleaner fuels, and the need to be more self-reliant in energy sources. Continued strong growth of the corn ethanol industry will depend on profitability by both suppliers and producers. This in turn will be influenced by several factors such as demand, government incentives, feedstock availability and prices, processing plant capacity, and efficient farm and ethanol processing technologies. How and to what extent will the projected growth of the corn ethanol industry in the United States be influenced by some or all of these factors? We use system dynamics modeling to construct a causal-loop structure of the corn ethanol industry and stock and flow diagrams to explore how possible changes in projected factors and growth indicators will affect the industry. Currently, planners and researchers explore various energy supply options by the year 2030. Using system dynamics modeling, this paper explores different possible growth scenarios of the industry for the next twenty years.
Development of New Zeolite 13X/CaCl2 Composite Adsorbent for Air-Conditioning Application
Authors: Chan K. C. , Chao Christopher Y. H. , Sze-To G. N. , Hui K. S.
Published: March 2012

Composite adsorbents synthesized from zeolite 13X and CaCl2 were investigated for applications in solar adsorption systems. The effect of Ca-ion-exchange on the adsorption properties of zeolite 13X was studied. Sodium ions in the zeolite structure were replaced by calcium ions by ion exchange. It was found that the Ca-ion-exchange process decreased the specific surface areas of the Ca-ion-exchanged zeolites while the total pore volumes were increased. The optimized Ca-ion-exchange condition existed when soaking zeolite 13X in 46wt% CaCl2 solution for 36 hours. The increase in the total pore volume is good for further impregnating the zeolite with CaCl2. A large difference in equilibrium water uptake, 0.404g/g, between 25°C and 100°C under 870Pa was recorded for the 13X/CaCl2 composite adsorbent impregnated in 40wt% CaCl2 solution. This was 295% of that of zeolite 13X under the same condition. The 13X/CaCl2 composite adsorbent showed a high potential in replacing vapor compression chillers in producing chilled water for central air-conditioning systems.
Exploration of Renewable Energy Usage in a Cement Kiln Using Downdraft Gasification of Poultry Litter
Authors: Hains Bryant T. , Burch Thomas E. , Bhavnani Sushil H. , Brodbeck Christian J.
Published: March 2012

Waste biomass, most notably poultry litter, is a potential source of energy that is widely available and cheap, especially in the southeast. Using poultry litter as an energy source provides a year-round outlet for this waste product. One major energy user that currently utilizes alternative solid fuels is the cement industry. Poultry litter in its raw state, however, is limited in use because of its high chlorine content and relatively large concentration of other unwanted constituents. Downdraft biomass gasification of pelletized poultry litter is a proposed solution to this problem as a means to produce a clean, consistent product gas for injection into the kiln. In this study, this process has been analyzed through experimentation on a pilot-scale 65 Nm3/hr syngas production downdraft gasifier to determine its effectiveness and consistency in this application. The low ash fusion temperature and high alkali content of poultry litter prove to be difficult obstacles to overcome as ash clinker formation is an issue. Experiments with temperature depression via flue gas recirculation as well as experiments employing an additive (lime) to prevent fusion and aid in chlorine retention in the ash have been carried out. Flue gas recirculation allowed the reduction of the gasifier secondary air oxygen concentration by 40–45%, yielding an approximately 100°C depression in average temperature. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Lime also has only a slight effect on the fusion when used to coat the pellets. However, lime addition does display some promise in regards to chlorine capture, as ash analyses show chlorine concentrations of more than four times greater in the lime infused ash as compared to raw poultry litter. Experiments were also conducted to explore the effectiveness of mixing lime with raw poultry litter, the object being to coat more surface area and have a more even mixture. These resulted in more consistent experiments with no ash clinkering.
Increasing Energy Efficiency of HVAC Systems of Buildings Using Phase Change Material
Authors: Chusak Lee , Daiber Jared , Agarwal Ramesh
Published: March 2012

Using Computational Fluid Dynamics (CFD), four different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare arrangements for (a) an all-air overhead system (mixing ventilation), (b) a combined air and hydronic radiant system (overhead system with a chilled ceiling), (c) an all-air raised floor system (displacement ventilation), and (d) a combined air and hydronic radiant system (displacement ventilation with a chilled ceiling). The computational domain for each model consists of one temperature varying wall (simulating the temperature of the exterior wall of the building during a 24-hour period) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations are conducted. The first set considers a glass window and plastic shade configuration for the exterior wall to compare the four cooling systems. The second set of computations consider a glass window, a phase change material layer and the plastic shade configuration for the exterior wall to examine the effect of the phase change material (PCM) layer on the cooling energy requirements. Both sets of simulations assumed an external wall that changed temperature as a function of time simulating the temperature changes on the exterior wall of the room during a 24 hour period. Results show superior thermal comfort levels as well as substantial energy savings can be accrued using the displacement ventilation and especially the displacement ventilation with a chilled ceiling over the conventional overhead mixing ventilation system. The results also show that the addition of a PCM layer to the exterior wall can significantly decrease the cooling energy requirements.
Coupled Transient System Analysis: A New Method of Passive Thermal Energy Storage Modeling for High Temperature Concentrated Solar Power Systems
Authors: Muren Russell , Arias Diego , Chapman Daniel , Erickson Luke , Gavilan Antonio
Published: March 2012

A comprehensive analysis of passive storage systems was developed consisting of sizing, transient performance and cost models. The sizing model is described in an earlier paper. The transient model, written in TRNSYS, was developed to predict the performance of each storage system when coupled with a realistic solar field and powerblock. This effort includes the creation of a time and space discretized numerical, adaptive grid model and a suite of controllers. The model in TRNSYS was implemented to provide hourly or sub-hourly performance data for an entire CSP plant with passive storage. During the course of the work passive phase change material storage was the focus; although purely sensible passive storage systems, such as concrete and ceramic, were also considered. It was found that previous sizing model methodology developed in both industry and academia is insufficiently robust and does not produce trust-worthy sizing information when used to cost passive storage systems. Furthermore, it was found that, especially for passive TES systems, transient coupled system modeling is a requirement for correct size and cost calculations. Finally, it was found that the current figures of merit, namely cost per kWh LSC, are ineffective means of capturing the real comparative cost of a storage system. In the course of the work a new storage control paradigm for passive systems has been developed. Additionally, new modeling methodology, figures of merit, and performance sizing criteria are presented.
Net Zero Energy Analysis Approach for Military Installations
Authors: Anderson Kate , Booth Samuel , Burman Kari , Callahan Michael
Published: March 2012

Net zero energy is a concept of energy self-sufficiency based on minimized demand and use of local renewable energy resources. A net zero energy military installation is defined as: “A military installation that produces as much energy on-site from renewable energy generation or through the on-site use of renewable fuels, as it consumes in its buildings, facilities, and fleet vehicles.” [1] The National Renewable Energy Laboratory (NREL) developed a comprehensive, first-of-its-kind strategy for evaluating a military installation’s potential to achieve net zero energy status, including an assessment of baseline energy use, energy use reduction opportunities from efficiency or behavior changes, renewable energy generation opportunities, electrical systems analysis of renewable interconnection, microgrid potential, and transportation energy savings. This paper describes NREL’s net zero energy assessment strategy and provides a planning guide for other organizations interested in evaluating net zero potential. We also present case studies and describe lessons learned from NREL’s net zero energy assessments at seven installations, including the importance of enforcing and funding mandates, providing leadership support, collecting accurate data, and selecting appropriate technologies. Finally, we evaluate whether the net zero concept is a useful framework for analyzing an energy strategy and a reasonable goal.
Solar Adsorption Refrigerator With Work Pair Economical
Authors: Trujeque Bolio Jessica G. , Ramirez Hernandez Julio Cesar
Published: March 2012

Anthropogenic production of cold is necessary for the preservation of the food industry, industrial processes, ice making, refrigeration and domestic conditioning of fixed and mobile spaces, emphasizing the importance in the health sector for the preservation of vaccines, biological and vital organs. Al ready exist technology who use power supply to produce cold, causing global warming as part of the side effect of CO2 from burning fossil fuel for power plants. Currently being researched and developed alternative technology that who operates with solar energy and requires no power supply. The market is looking for competitive cooling technologies operating systems generally, to raise the development of a solar refrigerator design for hot humid climate in Mexico, for the most critical environmental conditions of sunlight in a highly demanding cold technology.
Experimental Investigation of Thermal Storage Processes in a Thermocline Storage Tank
Authors: Karaki Wafaa , Li Peiwen , Van Lew Jon , Valmiki M. M. , Chan Cholik , Stephens Jake
Published: March 2012

This paper presents an experimental study and analysis of the heat transfer of energy charge and discharge in a packed-bed thermocline thermal storage tank for application in concentrated solar thermal power plants. Because the energy storage efficiency is a function of many parameters including fluid and solid properties, tank dimensions, packing dimensions, and time lengths of charge and discharge, this paper aims to provide experimental data and a proper approach of data reduction and presentation. To accomplish this goal, dimensionless governing equations of energy conservation in the heat transfer fluid and solid packed-bed material are derived. The obtained experimental data will provide a basis for validation of mathematical models in the future.
Gasification of Biomass to Second Generation Biofuels: A Review
Authors: Gu¨ell Berta Matas , Sandquist Judit , So̸rum Lars
Published: March 2012

Biomass gasification has gained significant attention in the last couple of decades for the production of heat, power and second generation biofuels. Biomass gasification processes are highly complex due to the large number of reactions involved in the overall process as well as the high sensitivity of the process to changes in the operational conditions. This report reviews the state-of-the-art of biomass gasification by evaluating key process parameters such as gasifying agent, temperature, pressure, particle size, etc., for fluidized bed and entrained flow gasifiers. The pros and cons of each technology and the remaining bottlenecks are also addressed.
An Analysis Model for Domestic Hot Water Distribution Systems
Authors: Maguire Jeff , Fang Xia , Krarti Moncef
Published: March 2012

A thermal model was developed to estimate the energy losses from prototypical domestic hot water (DHW) distribution systems for homes. The developed model, using the TRNSYS simulation software, allows researchers and designers to better evaluate the performance of hot water distribution systems in homes. Modeling results were compared with past experimental study results and showed good agreement. The model was also compared with existing domestic hot water distribution system modeling software HWSIM for verification. The developed model has several capabilities that are not available in HWSIM, including the ability to integrate any new or existing types of water heater systems, the ability to handle several simultaneous draws to different end uses, and the ability to handle unique annual draw profiles instead of weekly draw profiles. It also allows for draw profiles and ambient conditions to be considered using any time resolution. To demonstrate the abilities of this new model, a series of sensitivity analyses were performed using a benchmark domestic hot water distribution system. The effects of adding insulation to the domestic hot water distribution system of homes with a gas water heater and a solar water heater were also examined.
Projection of Flat-Plane Fluxmap Images Onto Non-Flat Receiver Surfaces
Authors: Yellowhair Julius , Andraka Charles E.
Published: March 2012

When designing or evaluating a dish concentrator system, it is desirable to determine the incident flux profile on the receiver surface, regardless of the absorber surface geometry. During the design process, analytical tools are used to predict flux profiles. During product evaluation, a flux-mapper (beam characterization system) can be used to measure the flux profile on a flat target surface. Radiosity concerns typically limit flux mapping measurements of dish-engine systems to a flat plate target. We propose and demonstrate an analytical method to project such a measured flat-target flux profile onto a non-flat receiver surface. We analytically estimate the angular content of the flux profile, and use this estimate combined with the measured flat-plate flux profile to project an estimate of the flux pattern onto another receiver surface. In this paper, we analytically demonstrate the technique. We first model a dish concentrator using CIRCE2. We then develop an analytic flux-map, in CIRCE2, on a flat target, simulating a flux-mapper output. Next, we use our new software tool and the CIRCE2 angular flux binning to project this flux pattern onto a non-flat receiver surface. Finally, we run a CIRCE2 model of the same dish with the non-flat target geometry, and compare this CIRCE2 output to the projected data. We also demonstrate the technique using a measured flux-map from a dish system in the field.
Evaluating the Energy Intensity of the US Public Water System
Authors: Twomey Kelly M. , Webber Michael E.
Published: March 2012

Previous analyses have concluded that the United State’s water sector uses over 3% of national electricity consumption for the production, conveyance, and treatment of water and wastewater and as much as 10% when considering the energy required for on-site heating, cooling, pumping, and softening of water for end-use. The energy intensity of water is influenced by factors such as source water quality, its proximity to a water treatment facility and end-use, its intended end-use and sanitation level, as well as its conveyance to and treatment at a wastewater treatment facility. Since these requirements differ by geographic location, climate, season, and local water quality standards, the energy consumption of regional water systems vary significantly. While national studies have aggregated averages for the energy use and energy intensity of various stages of the of the US water system, these estimates do not capture the wide disparity between regional water systems. For instance, 19 percent of California’s total electricity generation is used to withdraw, collect, convey, treat, distribute, and prepare water for end-use, nearly doubling the national average. Much of this electricity is used to move water over high elevations and across long distances from water-rich to water-stressed regions of the state. Potable water received by users in Southern California has typically been pumped as far as 450 miles, and lifted nearly 2000ft over the system’s highest point in the Tehachapi Mountains. Consequently, the energy intensity of San Diego County’s water is approximately 11,000 kWh per million gallons for pumping treatment and distribution, as compared to the US average which is estimated to be in the vicinity of 1,500–2,000 kWh per million gallons. With added pressures on the state’s long-haul transfer systems from population growth and growing interest in energy-intensive desalination, this margin will likely increase. This manuscript consists of a first-order analysis to quantify the energy embedded in the US public water supply, which is the primary water source to residential, commercial, and municipal users. Our analysis finds that energy use associated with the public water supply is 4.7% of the nation’s annual primary energy and 6.1% of national electricity consumption, respectively. Public water and wastewater pumping, treatment, and distribution, as well as commercial and residential water-heating were considered in this preliminary work. End-use energy requirements associated with water for municipal, industrial, and self-supplied sectors (i.e. agriculture, thermoelectric, mining, etc.) were not included in this analysis.
Numerical Analysis of a Rooftop Vertical Axis Wind Turbine
Authors: Uzarraga-Rodriguez N. Cristobal , Gallegos-Mun˜oz A. , Riesco A´vila J. Manuel
Published: March 2012

A numerical analysis of a rooftop vertical axis wind turbine (VAWT) for applications in urban area is presented. The numerical simulations were developed to study the flow field through the turbine rotor to analyze the aerodynamic performance characteristics of the device. Three different blade numbers of wind turbine are studied, 2, 3 and 4, respectively. Each one of the models was built in a 3D computational model. The effects generated in the performance of turbines by the numbers of blades are considered. A Sliding Mesh Model (SMM) capability was used to present the dimensionless form of coefficient power and coefficient moment of the wind turbine as a function of the wind velocity and the rotor rotational speed. The numerical study was developed in CFD using FLUENT®. The results show the aerodynamic performance for each configuration of wind turbine rotor. In the cases of Rooftop rotor the power coefficient increases as the blade number increases, while in the case of Savonius rotor the power coefficient decrease as the blades number increases.