bluuebunny/crossref_metadata_2025 huggingface dataset:
Toward a General Theory of Adaptive Radiation
Authors: Kassen Rees
Published: June 2009

The history of life has been punctuated by unusually spectacular periods of evolutionary diversification called adaptive radiation. Darwin's finches in the Galapagos, cichlid fishes in African Rift and Nicaraguan crater lakes, and the emergence of mammals at the end of the Cretaceous are hallmark examples. Although we have learned much from these and other case studies about the mechanisms thought to drive adaptive radiations, convincing experimental tests of theory are often lacking for the simple reason that it is usually impossible to “rewind the tape of life,” as Stephen Jay Gould was fond of saying, and run it again. This situation has changed dramatically in recent years with the increasing emphasis on the use of microbial populations which, because of their small size and rapid generation times, make possible the construction of replicated, manipulative experiments to study evolution in the laboratory. Here I review the contributions that microbial experimental evolution has made to our understanding of the ecological and genetic mechanisms underlying adaptive radiation. I focus on three major gaps in the theory of adaptive radiation—the paucity of direct tests of mechanism, the genetics of diversification, and the limits and constraints on the progress of radiations—with the aim of pointing the way toward the development of a more general theory of adaptive radiation.
An Extended Synthesis for Evolutionary Biology
Authors: Pigliucci Massimo
Published: June 2009

Evolutionary theory is undergoing an intense period of discussion and reevaluation. This, contrary to the misleading claims of creationists and other pseudoscientists, is no harbinger of a crisis but rather the opposite: the field is expanding dramatically in terms of both empirical discoveries and new ideas. In this essay I briefly trace the conceptual history of evolutionary theory from Darwinism to neo‐Darwinism, and from the Modern Synthesis to what I refer to as the Extended Synthesis, a more inclusive conceptual framework containing among others evo–devo, an expanded theory of heredity, elements of complexity theory, ideas about evolvability, and a reevaluation of levels of selection. I argue that evolutionary biology has never seen a paradigm shift, in the philosophical sense of the term, except when it moved from natural theology to empirical science in the middle of the 19th century. The Extended Synthesis, accordingly, is an expansion of the Modern Synthesis of the 1930s and 1940s, and one that—like its predecessor—will probably take decades to complete.
Suicidality Connected with Mentalizing Anomalies in Schizophrenia
Authors: Duñó Rosó , Pousa Esther , Miguélez Mónica , Montalvo Itziar , Suarez David , Tobeña Adolf
Published: June 2009

Deficits in social cognition contribute to the severe difficulties in daily functioning of schizophrenic patients, although they have never been connected with suicidality. Theory of mind (ToM) tasks explore basic social abilities and have been found to be defective in schizophrenia. The relationship between ToM anomalies and suicidal history was studied in a sample of 57 stabilized outpatients. Logistic regression analysis showed an association between poor performance on second‐order ToM tasks and a greater likelihood of suicidality in schizophrenic patients (OR = 4.02, 95% CI 1.18–13.62), which was independent of current clinical and neuropsychological status, with the exception of poor premorbid adjustment in infancy and adolescence. We caution against potential biases from mixing cross‐sectional ToM scores with lifetime suicidal records and retrospective assessments of premorbid adjustment through repeated testing of patients and their relatives. Hence, the present findings suggest that ToM deficits may contribute to the high risk of suicide in schizophrenia.
Power and Pragmatics
Authors: Keating Elizabeth
Published: June 2009

Language is an important means through which power relations are created and negotiated. In addition to everyday choices speakers make about their own language use, variations in ways of talking are related to local theories of power, status, identity, self, ethnicity, class, and gender. Grammatical and lexical choices, choices in forms of address and reference, turn‐taking, narratives of cause and effect, genre, and stylistic performance, as well as the organization of space for talk and participation, embodied behaviors, and silence are used as elements in the distribution of power. Power and language are connected through the marking of certain encounters and contexts as requiring particular types of language use, the privileging of certain types of language, who may or may not speak in certain settings, which contexts are appropriate for which types of speech and which for silence, what types of talk are appropriate to persons of different statuses and roles, norms for requesting and giving information, and practices for alternating between speakers. Pragmatic uses of language are an important tool for constructing social difference and distinctions between individuals in terms of efficacy and power.
The Ecological Role and Geography of Reindeer (Rangifer tarandus) in Northern Eurasia
Authors: Forbes Bruce C. , Kumpula Timo
Published: June 2009

The reindeer is a ruminant of the family Cervidae with a circumpolar distribution that has been a key component of Eurasian high latitude ecosystems for at least 2 million years. Interactions with humans date from the late Pleistocene onward and wild and semi‐domestic animals continue to be highly valued by aboriginal and non‐native peoples for a diversity of purposes. As a widespread and dominant ungulate across many tundra and taiga regions, the reindeer exerts a number of important controls on ecosystem structure and function. Animals, both free‐ranging and herded, move seasonally between summer, winter and transitional spring/autumn habitats or ‘pastures’. Their effects on vegetation and soils vary greatly in space and time depending on factors such as altitude/exposure, snow depth, substrate, moisture, prevailing vegetation type and, most importantly, animal density. At present, the number of Old World reindeer is somewhat less than 2.5 million. The most productive semi‐domestic herds occur in Fennoscandia and the Nenets regions of northwest Russia straddling the Ural Mountains. Management systems differ within and among countries and regions. Given the diverse suite of factors involved, changes in vegetation associated with grazing and trampling can be remarkably heterogeneous spatially yet remain to a large extent predictable. Potential threats facing reindeer populations of Eurasia include rapid land use change, climate change and ongoing institutional conflicts.
Image Analysis of Representative Food Structures: Application of the Bootstrap Method
Authors: Ramírez Cristian , Germain Juan C. , Aguilera José M.
Published: June 2009

ABSTRACT:  Images (for example, photomicrographs) are routinely used as qualitative evidence of the microstructure of foods. In quantitative image analysis it is important to estimate the area (or volume) to be sampled, the field of view, and the resolution. The bootstrap method is proposed to estimate the size of the sampling area as a function of the coefficient of variation (CVBn) and standard error (SEBn) of the bootstrap taking sub‐areas of different sizes. The bootstrap method was applied to simulated and real structures (apple tissue). For simulated structures, 10 computer‐generated images were constructed containing 225 black circles (elements) and different coefficient of variation (CVimage). For apple tissue, 8 images of apple tissue containing cellular cavities with different CVimage were analyzed. Results confirmed that for simulated and real structures, increasing the size of the sampling area decreased the CVBn and SEBn. Furthermore, there was a linear relationship between the CVimage and CVBn. For example, to obtain a CVBn = 0.10 in an image with CVimage = 0.60, a sampling area of 400 × 400 pixels (11% of whole image) was required, whereas if CVimage = 1.46, a sampling area of 1000 × 100 pixels (69% of whole image) became necessary. This suggests that a large‐size dispersion of element sizes in an image requires increasingly larger sampling areas or a larger number of images.
Acquired arachnoid cyst in a cat
Authors: Sugiyama T , Simpson DJ
Published: June 2009

A 5‐year‐old Birman cat presented with paraparesis associated with a fracture of the third thoracic vertebra and was managed conservatively. Voluntary function was regained over the next 6 months, but the cat was referred 4 years after the trauma because of recurrence of hindlimb paresis and ataxia. Magnetic resonance imaging (MRI) showed a spinal arachnoid cyst at the level of the fourth thoracic vertebra, which was treated surgically by dorsal laminectomy and durectomy, and hindlimb function subsequently recovered. The cat re‐presented 4 years later for recurrent hindlimb paresis. Myelography and computed tomography–myelography (CT‐M) showed dorsolateral pooling of cerebrospinal fluid (CSF) at the previous laminectomy site. The neurological signs after the second surgery improved, but not as much as after the first surgery and the cat remained ataxic with moderate paresis. Seven months later repeat CT‐M revealed an atrophic spinal cord, but negligible pooling of CSF at the previous site of the arachnoid cyst. The cat could walk, but was being treated for self‐induced trauma of the left hindlimb that was thought to be related to paraesthesia. The neurological signs gradually deteriorated over 3 months and the cat was euthanased.
BAALC and ERG expression in acute myeloid leukemia with normal karyotype: impact on prognosis
Authors: EID M. A. , ATTIA M. , ABDOU S. , EL‐SHAZLY S. F. , ELAHWAL L. , FARRAG W. , MAHMOUD L.
Published: June 2009

Cytogenetic aberrations are important prognostic factors in acute myeloid leukemia (AML). About 45% of de novo AML lack cytogenetic abnormalities, so identification of predictive molecular markers might improve therapy. We studied the prognostic impact of brain and acute leukemia, cytoplasmic (BAALC) and ETS‐related gene (ERG) expression in AML with normal karyotype. Pretreatment bone marrow samples from 30 cytogenetically normal AML patients were analysed for BAALC and ERG expression using real time RT‐PCR. The patients were dichotomized at BAALC and ERG mean expression into low and high expression. BAALC showed high expression in 70% of patients and its expression did not correlate with the clinical parameters of patients. ERG was high in 33.3% of patients and its expression was associated with lower ages and higher white cell counts. With follow‐up for 2 years, patients with high BAALC and high ERG had low rates of clinical remission (P < 0.005) and inferior overall survival (OS) (P < 0.001 and <0.002 for BAALC and ERG respectively). No significant association was observed between the increase in BAALC and ERG expression (P = 0.398). Multivariable analysis confirmed high BAALC expression as an independent risk factor for OS. Overexpression of BAALC and ERG either separate or concomitant predict adverse clinical outcome and may define important risk factor in cytogenetically normal AML.
One‐Sided Coverage Intervals for a Proportion Estimated from a Stratified Simple Random Sample
Authors: Kott Phillip S. , Liu Yan K.
Published: June 2009

Using an Edgeworth expansion to speed up the asymptotics, we develop one‐sided coverage intervals for a proportion based on a stratified simple random sample. To this end, we assume the values of the population units are generated from independent random variables with a common mean within each stratum. These stratum means, in turn, may either be free to vary or are assumed to be equal. The more general assumption is equivalent to a model‐free randomization‐based framework when finite population correction is ignored. Unlike when an Edgeworth expansion is used to construct one‐sided intervals under simple random sampling, it is necessary to estimate the variance of the estimator for the population proportion when the stratum means are allowed to differ. As a result, there may be accuracy gains from replacing the normal z‐score in the Edgeworth expansion with a t‐score.
Assessing oil resources in the Middle East and North Africa
Authors: Aguilera Roberto F.
Published: June 2009

Some energy experts are concerned that the world will soon face a global crisis to dwindling oil resources and a peak in production. This paper analyses the concern by estimating a cumulative supply curve for conventional oil in the Middle East and North Africa (MENA) region. It does so by attaching production costs to the endowment volumes of oil in the region, including volumes from provinces not previously assessed. A Variable Shape Distribution model is used to estimate the volumes of the previously unassessed provinces.

The findings show that MENA oil should last far longer than some concerned experts claim. In addition, the production costs are lower than current market oil prices and significantly lower than prices observed in mid‐2008.
α‐MSH tripeptide analogs activate the melanocortin 1 receptor and reduce UV‐induced DNA damage in human melanocytes
Authors: Abdel‐Malek Zalfa A. , Ruwe Andrew , Kavanagh‐Starner Renny , Kadekaro Ana Luisa , Swope Viki , Haskell‐Luevano Carrie , Koikov Leonid , Knittel James J.
Published: June 2009

One skin cancer prevention strategy that we are developing is based on synthesizing and testing melanocortin analogs that reduce and repair DNA damage resulting from exposure to solar ultraviolet (UV) radiation, in addition to stimulating pigmentation. Previously, we reported the effects of tetrapeptide analogs of α‐melanocortin (α‐MSH) that were more potent and stable than the physiological α‐MSH, and mimicked its photoprotective effects against UV‐induced DNA damage in human melanocytes. Here, we report on a panel of tripeptide analogs consisting of a modified α‐MSH core His6‐d‐Phe7‐Arg8, which contained different N‐capping groups, C‐terminal modifications, or arginine mimics. The most potent tripeptides in activating cAMP formation and tyrosinase of human melanocytes were three analogs with C‐terminal modifications. The most effective C‐terminal tripeptide mimicked α‐MSH in reducing hydrogen peroxide generation and enhancing nucleotide excision repair following UV irradiation. The effects of these three analogs required functional MC1R, as they were absent in human melanocytes that expressed non‐functional receptor. These results demonstrate activation of the MC1R by tripeptide melanocortin analogs. Designing small analogs for topical delivery should prove practical and efficacious for skin cancer prevention.
Prescribing Statins to Patients with Nonalcoholic Fatty Liver Disease: Real Cardiovascular Benefits Outweigh Theoretical Hepatotoxic Risk
Authors: Riley P. , Al Bakir M. , O’Donohue J. , Crook M.
Published: June 2009

Statins are among the most widely prescribed drugs in the western world and play a significant role in reducing cardiovascular risk. However, concern regarding their hepatic safety profile has meant that patients with concurrent liver pathology are often denied such benefits. In this review we consider the evidence for and against the prescription of statins to patients with nonalcoholic fatty liver disease, a group typically associated with high cardiovascular risk. Contrary to current opinion, we find that there is considerable evidence for and little evidence against the prescription of statins to this population and suggest that the guidelines advising against their use in these patients should be reviewed.
What’s Metaphysical About Metaphysical Necessity?1
Authors: CAMERON ROSS P.
Published: June 2009

I begin by contrasting three approaches one can take to the distinction between the essential and accidental properties: an ontological, a deflationary, and a mind‐dependent approach. I then go on to apply that distinction to the necessary a posteriori, and defend the deflationist view. Finally I apply the distinction to modal truth in general and argue that the deflationist position lets us avoid an otherwise pressing problem for the actualist: the problem of accounting for the source of modal truth.
Assertion and its Constitutive Norms
Authors: RESCORLA MICHAEL
Published: June 2009

Alston, Searle, and Williamson advocatethe restrictive model of assertion, according to which certain constitutive assertoric normsrestrictwhich propositions one may assert. Sellars and Brandom advocatethe dialectical model of assertion, which treats assertion as constituted by its role in the game of giving and asking for reasons. Sellars and Brandom develop a restrictive version of the dialectical model. I explore anon‐restrictiveversion of the dialectical model. On such a view, constitutive assertoric norms constrain how one must react if an interlocutor challenges one’s assertion, but they donotconstrain what one should assert in the first place. I argue that the non‐restrictive dialectical perspective can accommodate various linguistic phenomena commonly taken to support the restrictive model.1
Calcium diffusion enhanced after cleavage of negatively charged components of brain extracellular matrix by chondroitinase ABC
Authors: Hrabětová Sabina , Masri Daniel , Tao Lian , Xiao Fanrong , Nicholson Charles
Published: June 2009

The concentration of extracellular calcium plays a critical role in synaptic transmission and neuronal excitability as well as other physiological processes. The time course and extent of local fluctuations in the concentration of this ion largely depend on its effective diffusion coefficient (D*) and it has been speculated that fixed negative charges on chondroitin sulphate proteoglycans (CSPGs) and other components of the extracellular matrix may influence calcium diffusion because it is a divalent cation. In this study we used ion‐selective microelectrodes combined with pressure ejection or iontophoresis of ions from a micropipette to quantify diffusion characteristics of neocortex and hippocampus in rat brain slices. We show that D* for calcium is less than the value predicted from the behaviour of the monovalent cation tetramethylammonium (TMA), a commonly used diffusion probe, but D* for calcium increases in both brain regions after the slices are treated with chondroitinase ABC, an enzyme that predominantly cleaves chondroitin sulphate glycans. These results suggest that CSPGs do play a role in determining the local diffusion properties of calcium in brain tissue, most likely through electrostatic interactions mediating rapid equilibrium binding. In contrast, chondroitinase ABC does not affect either the TMA diffusion or the extracellular volume fraction, indicating that the enzyme does not alter the structure of the extracellular space and that the diffusion of small monovalent cations is not affected by CSPGs in the normal brain ionic milieu. Both calcium and CSPGs are known to have many distinct roles in brain physiology, including brain repair, and our study suggests they may be functionally coupled through calcium diffusion properties.
Real‐time monitoring of cAMP levels in living endothelial cells: thrombin transiently inhibits adenylyl cyclase 6
Authors: Werthmann R.C. , Von Hayn K. , Nikolaev V.O. , Lohse M.J. , Bünemann M.
Published: June 2009

The crosstalk between Ca2+ and cAMP signals plays a significant role for the regulation of the endothelial barrier function. The Ca2+‐elevating agent thrombin was demonstrated to increase endothelial permeability and to decrease cAMP levels. Since Ca2+ and cAMP signals are highly dynamic, we aimed to study the temporal resolution between thrombin‐evoked Ca2+ signals and subsequent changes of cAMP levels. Here we conduct the first real‐time monitoring of thrombin‐mediated regulation of cAMP signals in intact human umbilical vein endothelial cells (HUVECs) by utilising the Ca2+‐sensitive dye Fluo‐4 and the fluorescence resonance energy transfer (FRET)‐based cAMP sensor Epac1‐camps. We calibrated in vitro FRET responses of Epac1‐camps to [cAMP] in order to estimate changes in intracellular [cAMP] evoked by thrombin treatment of HUVECs. After increasing [cAMP] to 1.2 ± 0.2 μm by stimulation of HUVECs with isoproterenol (isoprenaline), we observed a transient decrease of cAMP levels by 0.4 ± 0.1 μm which reached a minimum value 30 s after thrombin application and 15 s after the thrombin‐evoked Ca2+ peak. This transient decrease in [cAMP] was Ca2+‐dependent and independent of a Gi‐mediated inhibition of adenylyl cyclases (ACs). Instead the knock down of the predominant subtype AC6 in HUVECs provided the first direct evidence that the Ca2+‐mediated inhibition of AC6 accounts for the thrombin‐induced decrease in cAMP levels.
Angiomotin p80/p130 ratio: a new indicator of exercise‐induced angiogenic activity in skeletal muscles from obese and non‐obese rats?
Authors: Roudier Emilie , Chapados Natalie , Decary Simon , Gineste Charlotte , Le Bel Catherina , Lavoie Jean‐Marc , Bergeron Raynald , Birot Olivier
Published: June 2009

Skeletal muscle capillarisation responds to physiological and pathological conditions with a remarkable plasticity. Angiomotin was recently identified as a new pro‐angiogenic molecule. Angiomotin is expressed as two protein isoforms, p80 and p130. Whereas p80 stimulates endothelial cell migration and angiogenesis, p130 is rather characteristic of stabilized and matured vessels. To date, how angiomotin expression is physiologically regulated in vivo remains largely unknown. We thus investigated (1) whether angiomotin was physiologically expressed in skeletal muscle; (2) whether exercise training, known to stimulate muscle angiogenesis, affected angiomotin expression; and (3) whether such regulation was altered in obesity, a pathological situation often associated with an impaired angiogenic activity and some capillary rarefaction in skeletal muscle. Two models of obesity were used: a high fat diet regime and Zucker Diabetic Fatty rats (ZDF). Our results provide evidence that angiomotin was expressed both in capillaries and myofibres. In non‐obese rats, the p80 isoform was increased in plantaris muscle in response to endurance training whereas p130 was unaffected. In obese animals, no change was observed for p80 whereas training significantly decreased p130 expression. Exercise training induced angiogenesis in plantaris from both obese and non‐obese rats, possibly through the modulation of angiomotin level and its consequences on RhoA–ROCK signalling. In conclusion, any increase in p80 or decrease in p130, as respectively observed in non‐obese and obese animals, led to an increased ratio between p80 and p130 isoforms. This increased angiomotin p80/p130 ratio might then directly reflect the enhanced angiogenic ability of skeletal muscle in response to exercise training.
Status and Issues of Hydrogen Energy R&D in Korea
Authors: Chung Moon-Sun , Kim Jong-Won
Published: June 2009

In the era of fossil fuel shortage and soaring oil prices under the condition of severe environmental problems we are facing now, an increasing need for sustainable development of new energy technology as a substitute of fossil fuel has become an issue of great concern throughout the world. Most of energy consumed in Korea, over 96%, is imported from foreign countries, especially Middle East. Korea is now ranked the 10th energy consumed country in the world. That is why we are interesting in hydrogen economy. As a result, hydrogen and fuel cell technology was selected as one of economic growth engines for next generation, and strongly supported by Korea government. Also, the government set Hydrogen Economy Policy in 2005. There are four R&D programs on hydrogen and fuel cell in Korea. Two of them are supported by MEST (Ministry of Education, Science and Technology) and others are funded by MKE (Ministry of Knowledge Economy). The hydrogen production technologies examined in Korea cover 3 main bases, fossil fuel, renewable energy including bio-hydrogen technology, and nuclear power. In October 2003, Korean government launched Hydrogen Energy R&D Center (HERC) as a member of the 21st Century Frontier R&D programs supported by the Ministry of Education, Science and Technology (MEST). The HERC has conducted research on the key technologies for the production, storage, and utilization of hydrogen energy for expediting realization of hydrogen economy based on renewable energy sources. The main purposes of this paper are to overview the current status of research programs conducted by Hydrogen Energy R&D Center based on the patent applications as well as research topics and to introduce specific achievements in each research program.
Solar Nantenna Electromagnetic Collectors
Authors: Kotter Dale K. , Novack Steven D. , Slafer W. Dennis , Pinhero Patrick
Published: June 2009

This research explores a new efficient approach for producing electricity from the abundant energy of the sun. A nantenna electromagnetic collector (NEC) has been designed, prototyped, and tested. Proof of concept has been validated. The NEC devices target mid-infrared wavelengths, where conventional photovoltaic (PV) solar cells are inefficient and where there is an abundance of solar energy. The initial concept of designing NEC was based on scaling of radio frequency antenna theory. This approach has proven unsuccessful by many due to not fully understanding and accounting for the optical behavior of materials in the THz region. Also, until recent years the nanofabrication methods were not available to fabricate the optical antenna elements. We have addressed and overcome both technology barriers. Several factors were critical in successful implementation of NEC including: 1) frequency-dependent modeling of antenna elements; 2) selection of materials with proper THz properties; and 3) novel manufacturing methods that enable economical large-scale manufacturing. The work represents an important step toward the ultimate realization of a low-cost device that will collect, as well as convert this radiation into electricity, which will lead to a wide spectrum, high conversion efficiency, and low-cost solution to complement conventional PVs.
Performance Evaluation of Concentrating Solar Cooker Under Indian Climatic Conditions
Authors: Shukla S. K. , Gupta S. K.
Published: June 2009

The work presented in this paper essentially consists of modeling and analysis of energy and exergy efficiency of a community solar cooker, installed at Holistic Health and Food Centre, I.I.T. Delhi India in March 1998. The cooker is meant for community cooking, which consists of a linear parabolic concentrator with concentration ratio of 20. The experiments, on this cooker, were performed in summer and winter, both the climatic conditions. The measurements were done by using microprocessor based on line data acquisition system using class I solar pyranometer and Pt. 100 temperature sensors. Based on the experimental data obtained by testing and performance evaluation of this concentrating type of solar cooker, the energy and exergy efficiencies are calculated. From an analysis of the experimental values the average efficiency of this cooker is measured as 14% only. The different losses contributes to low efficiency are optical losses (16%), geometrical losses (30%) and thermal losses (35%) accounts for more than, 80% energy waste from the radiation coming to the reflector. The rest of the losses are due to edge losses etc. the maximum temperature of water was recorded 98°C during water heating tests.
Tank Design for On-Board Hydrogen Storage in Metal Hydrides
Authors: Couturier Karelle , Joppich Farida , Wo¨rner Antje , Tamme Rainer
Published: June 2009

The aim of this work is to reduce the refueling time of a metal hydride storage tank by improving its design, taking in account the total volumetric and mass capacity of the tank. A heat and mass transfer model is proposed and solved to obtain the charging curve for 1 kg hydrogen in a LaNi5 reference storage tank. Compared to gas transport and reaction kinetics, heat transfer is found to limit the hydrogen charging dynamics of the storage tank. To improve the refueling time, it is found to be necessary to increase first of all the heat transfer inside the metal hydride bed, and subsequently the heat transfer from the metal hydride bed to the cooling fluid. Technical solutions such as the implementation of aluminum foam and/or internal heat exchanger tubes are investigated. By combining both solutions, the refueling time can be reduced from 400 minutes (reference tank) to 15 minutes. The tank volume still meets the DOE targets, but its mass remains a problem. Therefore, new materials with improved gravimetric capacity have to be developed. With this work it is now possible to improve the tank design for newly developed storage materials and to evaluate their potential for technical applications.
Second Law Analysis of Evaporator for Organic Rankine Cycle System
Authors: Gu Wei , Weng Yiwu
Published: June 2009

The evaporator is a key component for Organic Rankine Cycle (ORC) system. Second law analysis of the evaporator was carried out in this work. Three processes were included and studied: pre-heating, boiling and super-heating. Firstly, ε–NTU method was applied to study the heat transfer area of evaporator. Then, internal entropy generation for three processes of evaporator was studied by entropy generation number. Thirdly, entropy generation distribution (ds/dA) was predicted by analyzing the temperature difference between the two sides of single stage counter-flow evaporator, for both pure and mixed working fluids. The results show that increase of waste heat fluid temperature increases internal irreversibility, and higher evaporator pressure decreases this irreversibility. The results also show that temperature difference at the end part of boiling process is larger for pure working fluids; and for mixed fluids, because of its’ increasing boiling temperature, this irreversibility decreases remarkably. In conclusion, second law analysis shows that the evaporating pressure plays a key role in evaporator design for ORC system; and both evaporator and working fluid should be well designed to minimize the second law loss.
Distributed Combined Cooling Heating and Power System and Its Development Situation in China
Authors: Wang Jiangjiang , Jing Youyin , Zhang Chunfa , Zhang Bin
Published: June 2009

Distributed natural gas-driven combined cooling, heating and power (CCHP) systems, including various technologies, provide an alternative for the world to meet and solve energy-related problems, such as energy shortages, energy supply security, emission control, the economy and conservation of energy, etc. This paper analyzes the energy consumption structure in China at first; then the characteristics of natural gas-driven CCHP technologies, especially technical performances, are presented, as well as the status of utilization and development. The status of distributed CCHP development in China is briefly introduced by dividing China into four main sections: Beijing, Shanghai, Guangdong and other areas. Several problems regarding further distribution of natural gas-driven CCHP applications for buildings in China are discussed. It is concluded that, within decades, promising CCHP technologies can flourish with the cooperative efforts of government, energy-related enterprises and professional associations.
Analysis and Design of a Paraffin/Graphite Composite PCM Integrated in a Thermal Storage Unit
Authors: Pokhrel R. , Gonza´lez J. E. , Hight T. , Adalsteinsson T.
Published: June 2009

The addition of latent heat storage systems in solar thermal applications has several benefits including volume reduction of storage tanks and maintaining the temperature range of the thermal storage. A Phase change material (PCM) provides high energy storage density at a constant temperature corresponding to its phase transition temperature. In this paper, a high temperature PCM (melting temperature 80°C) made of a composite of paraffin and graphite was tested to determine its thermal properties. Tests were conducted with a differential scanning calorimeter (DSC) and allowed the determination of the melting and solidification characteristics, latent heat, specific heat at melting and solidification, and thermal conductivity of the composite. The results of the study showed an increase in thermal conductivity by a factor of 4 when the mass fraction of the graphite in the composite was increased to 16.5%. The specific heat of the composite PCM (i.e., CPCM) decreased as the thermal conductivity increased, while the latent heat remained the same as the PCM component. In addition, the phase transition temperature was not influenced by the addition of expanded graphite. To explore the feasibility of the CPCM for practical applications, a numerical solution of the phase change transition of a small cylinder was derived. Finally, based on the properties obtained in DSC, a numerical simulation for a known volume of CPCM in a water tank was produced and indicated a reduction in solidification time by a factor of six.
Modeling and Validation of Building Thermal Performance of the 2007 Santa Clara University Solar Decathlon House
Authors: Elizondo Hazel A. , Lebassi Bereket , Gonzalez-Cruz Jorge E.
Published: June 2009

Sustainability is an issue of great importance in the building and energy sectors. In the United States, about 40% of total energy use is in buildings, 30% of raw materials are used in buildings, 30% of waste outputs come from buildings, 30% of greenhouse gas emissions are attributed to buildings, and 12% of potable water consumption occurs in buildings. Thus, there is a great necessity for the rapid deployment of highly sustainable buildings that are aesthetic and reliable. Solar houses are highly sustainable and can be designed to be reliable by using streamlined technologies, providing as much power as needed, and by minimizing the energy usage within the building. The US DOE Solar Decathlon offered a great opportunity to test these criteria which were at the same time the fundamental elements taken into consideration when designing the Santa Clara University (SCU) solar house in 2007 [1]. In this research the SCU solar decathlon solar house energy and thermal performances were analyzed. The energy and thermal loads were modeled using EnergyPlus™ software which helps to perform detailed modeling of the energy and thermal performances of buildings. The conditioned space of the building consists of two rectangular shaped zones, the living room and the bedroom, which together are approximately 45ft along the east-west direction and 11ft wide. Wood framing with R-19 insulation, made from recycled jeans, was used for the walls. The roof and the floor are constructed of a bamboo wood frame with foam insulation. Daylighting was maximized through active windows (i.e. electro-chromic), energy efficient appliances were incorporated along with solar thermal air conditioning, heating and hot water. Performance parameters for the mechanical systems were developed from conventionally available technologies and the control set-points were based on DOE Solar Decathlon 2007 (SD07) guidelines [1]. The thermal energy design decisions for the house were based largely on a combination of the solar decathlon contest requirements and that technologies were sustainable and commercially available. The house was tested in Washington DC in October 2007 during the competition and performed excellently well ranking at the top in the following categories: energy balance, thermal comfort, and hot water. Data collected during the event provide the unique opportunity of validating the simulated energy and thermal performances of the house with weather file created from the real-time weather data. The created weather file is used to run new simulations of the SCU SD07 house, from these results we can assess the accuracy of the simulation program used. If accuracy is high enough, annual simulations are executed to demonstrate how the house would perform under extreme climatic conditions in different regions.
Energy Saving Studies in Industrial Facilities
Authors: Kanoglu Mehmet , Karabay Ilker , Dincer Ibrahim
Published: June 2009

Efficient energy use is critical for the success of any industrial facility since reduced energy consumption through energy conservation/saving programs can benefit not only consumers and utilities, but society in general as well. In particular, reduced energy consumption generally leads to reduced emissions of greenhouse gases and other air pollutants into the environment. It also helps reduce the operational costs in the facility. There is a strong need to take some energy saving measures in every plant/ facility. Although these may be quite diverse, some of these measures include thermal insulation, use of more efficient equipment, heat recovery systems, high efficiency lighting, changing the fuel, reducing the cost of compressed air, and enhancing productivity. In this study, some certain energy conservation measures are considered for assessing a packaging film manufacturing facility in Gaziantep, Turkey. Taking advantage of dry and hot climates of the city, cooling compressor inlet air by evaporative cooling technique is also assessed. Our investigation shows that there is a huge room for energy conservation measures. The total savings potential are expected to be 869,350 YTL (about $725,000) representing about 16% of the total energy consumption. The payback periods for the identified measures are justified. We believe that the results are typical rather than exceptional for the industrial sector in Turkey.
A Transcritical CO2 Rankine Cycle With LNG Cold Energy Utilization and Liquefaction of CO2 in Gas Turbine Emission
Authors: Huang Meibin , Lin Wensheng , He Hongming , Gu Anzhong
Published: June 2009

A novel transcritical Rankine cycle is presented in this paper. This cycle adopts CO2 as its working fluid, with exhaust from a gas turbine as its heat source and LNG as its cold sink. With CO2 working transcritically, large temperature difference for the Rankine cycle is realized. Moreover, the CO2 in the gas turbine exhaust is further cooled and liquefied by LNG after transferring heat to the Rankine cycle. In this way, not only the cold energy is utilized, but also a large part of the CO2 from burning of the vaporized LNG is recovered. In this paper, the system performance of this transcritical cycle is calculated. The influences of the highest cycle temperature and pressure to system specific work, exergy efficiency and liquefied CO2 mass flow rate are analyzed. The exergy loss in each of the heat exchangers is also discussed. It turns out that this kind of CO2 cycle is energy-conservative and environment-friendly.
Design Development and Testing of a Regenerative Rechargeable Solar Stove System
Authors: Ayalneh Abera Melesse , Ramayya A. Venkata
Published: June 2009

This paper deals with the development of a solar stove system that synthesizes the concepts of a reversible chemical reaction using CaO and water for heat generation, with that of the concentrated solar radiation for regeneration. A solar stove to take care of the needs of a standard family and which can be used at any time of the day has been designed, fabricated and used for experimental testing. A paraboloid solar concentrator has been conceived, designed and built to be used as a community facility in the neighborhood of the family for the regeneration of CaO from Ca(OH)2. Different aspects encompassing heat transfer, reaction kinetics, water injection along with structural integrity and safety have been given due consideration as also the implementation technicalities with regard to capacity, cost, user friendliness, efficiency, and adaptation of locally available materials etc. These and the experimental test results of the heat generation part of the stove system are presented and discussed. This stove system has the innate potential to endear itself to the end user and upon completion of the testing of the regeneration part can turn out to be that long term solution, one is looking for.
Piezoelectric Energy Conversion Using Locomotion
Authors: Howells Christopher A.
Published: June 2009

Piezoelectric materials can be used to convert oscillatory mechanical energy into electrical energy. This technology, together with innovative mechanical coupling designs, can form the basis for an energy harvesting solution for military and commercial systems. The US Army-CERDEC at Ft. Belvoir, VA and Continuum Photonics, Inc. in Billerica, MA completed a three year Science & Technology Objective (STO) research effort that focused on harvesting energy from physical exertion. The effort was aimed at investigating the concept of Piezoelectric Energy Harvesting for supplying supplemental power for dismounted soldiers. This STO effort resulted in the development of four proof-of-concept Heel Strike Units where each unit is essentially a small electric generator that utilizes piezoelectric elements to convert mechanical motion into electrical power in the form factor of the heel of a soldier’s combat boot. The Power Technology Branch has tested and evaluated the Heel Strike units. The results of the testing and evaluation and the performance of this small electric generator are presented. The generator’s piezoelectric conversion of mechanical motion into electrical power, its efficiency, the processes it goes through to produce useable power and commercial applications of the Heel Strike electric generator are discussed.
Spacing Analysis of an Inclined Solar Collector Field
Authors: Sadineni S. B. , Boehm R. F. , Hurt R.
Published: June 2009

Spacing between the adjacent collectors in a solar field is an important parameter which effects the shading and hence the energy conversion from collectors. Land value has an important bearing on the spacing between the collectors. A computer code has been developed to predict the change in incident energy on the collectors for various spacing distances between them. The code couples general shading models with the local weather data (TMY2). This can be used to calculate shadow area on the collectors from their adjacent collectors for different times of the day for various spacing distances. Variation of shadow area of the collectors for various spacing distances is presented for various time periods. It has been observed that near sunrise and sunset the percent shading area of a system is generally higher, but its influence on the overall energy collection is relatively less due to the decreased solar insolation available during those times of the day. The variation of annual energy received for various spacing distances is presented. Results are given for locations in the Southwestern region of the US including Las Vegas, Phoenix and Albuquerque. Economic implications of these results are discussed.
Self-Entrainment Characteristics and Performance of a Compact Air Ejector
Authors: Bulusu Kartik V. , Garris Charles A.
Published: June 2009

A one dimensional method of analysis and experimentally determined entrainment and compression ratios are presented with considerations made for constant pressure and constant area mixing. A set of three nozzles, one converging and two converging diverging, were used to study the isentropic characteristics of the ejector performance. Ejector efficiencies are calculated using the turbomachinery analogue of compressors where adiabatic and complete mixing of primary and secondary fluids is assumed before discharge. Efficiencies are characterized against non-dimensional parameters chosen in context. A generalized algorithm and corresponding MATLAB™ based computer program was developed for performance analysis. While exploring the possibility of a refrigeration system for automotive applications where the size of the ejector could play an important role, a compact experimental ejector was designed and tested.
Study on the Experiments of Flue Gas Denitrification and Desulfurization Using Nitric Acid Solution
Authors: Sun Bao-Ming , Yin Shui-E , Wang Zhong-Li
Published: June 2009

The present study attempts to take nitric acid as absorbent to clean up SO2 and NO gases simultaneously from the simulated flue gas in the lab-scale bubbling reactor, this study was divide into the individual DeNOx experiments and the combined DeSOx/DeNOx experiments: the individual DeNOx experiments were carried out to examine the effect of various operating parameters such as input NO concentration, nitric acid concentration, oxygen concentration input SO2 concentration, adding KMnO4 as additive and taking NaOH as the secondary absorption processes on the SO2 and NOx removal efficiencies at room temperature, the results of the individual DeNOx show that NO removal efficiency of 70%–95% were achieved under optimized conditions. NO removal efficiency increased with the increasing nitric acid concentration and increased by adding KMnO4 into the absorbent as additive as well. The removal efficiency of NO can reach 95% when using the two-step integrated processes of (HNO3+KMnO4)-NaOH, the absorption solution of 50% nitric acid, 400ppm of input NO concentration. 0.5% oxygen concentration and without SO2 in the simulated flue gas. No improvement on the NOx removal efficiency was observed with the increasing of KMnO4 and NaOH concentration in the scrubbing solution. The results of the combined DeSOx/DeNOx experiments show that the maximum DeNOx and DeSOx efficiencies ranged from 36.6% to 81% and from 99.4% to 100.0%, respectively. The prime parameters affecting the NOx removal efficiency are the oxygen concentration and the input SO2 concentration.
Analysis of Power Distribution and Sensitivity for the Power Synthesizer of Hybrid Electric Vehicle
Authors: Zhou Chunguo , Liu Hongzhao , Cui Yahui
Published: June 2009

The Power Synthesizer of Parallel Hybrid Electric Vehicle (PHEV) has been the research object. It is composed of the differential gear train, in which its power distribution and sensitivity has been analyzed as main problems. The transmission ratio, torque and power distribution have been analyzed about the gear train. Whatever its structure is, if only the value of structure parameter K is same, then the corresponding relative kinematics relation and mechanics relation of the basic components are same absolutely. The calculation of power distribution among basic components has been introduced. The sensitivity has direct influence to the mobile performance of vehicle, so the angular speed response for output components to input components has been analyzed, and the connecting mode between engine or motor and differential gear train has been bought forward. The analytical results can be helpful for the parameters’ design of kinematics and dynamics of the vehicle, and for the vehicle’s control.
Numerical Simulation of Indoor Air Flow in Capillary Plane HVAC Terminal System
Authors: Bing Wei , Li Li , Lu Jiang , Wei Zhang
Published: June 2009

The capillary plane terminal system is a novel HVAC system which can be used in office or residential buildings with dedicated outdoor air system. The capillary mats buried in the surface grout of the ceiling or the wall or the floor handle the interior sensible space cooling load with the handled dedicated air taking on the rest latent cooling load to keep the indoor parameters to be desired state. In this paper, with an example of a typical residential room where the capillary mats are installed on the ceiling, by using the method of CFD the indoor air flows under different modes in summer and winter are simulated and the temperature, velocity, relative humidity, predicted mean vote (PMV) and predicted percent dissatisfied (PPD) fields are presented and analyzed. Based on the simulation results, the indoor thermal environments are evaluated. And the optimal air flow mode is recommended correspondingly. These will be useful to the design and application of the capillary plane HVAC terminal system.