bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyzing temporally correlated dolphin sightings data using generalized estimating equations
Authors: Bailey Helen , Corkrey Ross , Cheney Barbara , Thompson Paul M.
Published: March 2012

Abstract

Many of the statistical techniques commonly used in ecology assume independence among responses. However, there are many marine mammal survey techniques, such as those involving time series or subgroups, which result in correlations within the data. Generalized estimating equations (GEEs) take such correlations into account and are an extension of generalized linear models. This study demonstrates the application of GEEs by modeling temporal variation in bottlenose dolphin presence from sightings data. Since dolphins could remain in the study area for several hours resulting in temporal autocorrelation, an autoregressive correlation structure was used within the GEE, each cluster representing hours within a day of survey effort. The results of the GEE model showed that there was significant diel, tidal, and interannual variation in the presence of dolphins. Dolphins were most likely to be seen in the early morning and during the summer months. Dolphin presence generally peaked during low tide, but this varied among years. There was a significantly lower probability of dolphins being present in 2003 than 2004, but not between 2004 and the other years (1991, 1992, and 2002). GEE‐model fitting packages are now readily available, making this a valuable, versatile tool for marine mammal biologists.
Effect of Maturity Stage and Storage on Flavor Compounds and Sensory Description of Berrycactus (Myrtillocactus geometrizans)
Authors: Alejandro Vazquez‐Cruz Moises , Jimenez‐Garcia Sandra Neli , Torres‐Pacheco Irineo , Horacio Guzman‐Maldonado Salvador , Guevara‐Gonzalez Ramon Gerardo , Miranda‐Lopez Rita
Published: March 2012

Abstract:  Descriptive sensory analysis combined with a chemical analysis, provided insight regarding sensory significance for a better understanding of berrycactus' flavor. This study was based on the volatile components derived from the gas chromatography‐olfactometry (GC‐O) analysis. Four different ripening stages were used for the experiments: unripe, red, transition, and over‐ripe. Besides red and transition stages were stored in sealed plastic bags for 7 d at 5 °C as an additional treatment in order to establish comparisons with fresh samples. GC‐O analysis was performed following OSME (time‐intensity) method. Moreover, chemical characterization was achieved through GC–MS analysis, each compound was tentatively identified by comparing its mass spectra with the spectra from the library NIST02, by its aroma notes and Kovats Index. The aroma descriptors found were: caramel, fruity, acetic acid, fresh, citrus, floral, and phenolics. Nine volatile compounds are among the most important in flavor of berrycactus: furfural, 5‐methyl‐2‐furancarboxaldehyde, 2(5H)‐furanone, 5‐acetoxymethyl‐2‐furaldehyde, 2‐cyclohexen‐1‐ol, octanoic acid ethyl ester, decanoic acid ethyl ester, octanoic acid, and phenylethyl alcohol. To better reflect the real responses of these compounds, the regression analysis of concentrations to ripening stages were performed. The 2,3‐dihydro‐3,5‐dihydroxy‐6‐methyl‐(4H)‐pyran‐4‐one was found in berrycactus, it has been reported in chemical profile of other berries as a product of heat‐induced reactions, however, this compound has no aroma activity. The data suggest that both furanones and esters contribute to the aroma of berrycactus. On the other hand, solid phase microextraction was found to be more useful in detecting esters and acids whereas solvent extraction was more effective in detecting furanones and ketones.

Practical Application:  This information could contribute to setting up favorable processing conditions; in order to retain the best sensory characteristics of berrycactus along with functional properties that would enhance commercialization and exploitation of this fruit and to promote berrycactus cultivation programs.
Modeling the Effect of Time and Temperature on Respiration Rate of Pomegranate Arils (cv. ``Acco'' and ``Herskawitz'')
Authors: Caleb Oluwafemi J. , Mahajan Pramod V. , Linus Opara Umezuruike , Witthuhn Corli R.
Published: March 2012

Abstract:  Understanding the effect of time and temperature on the respiration rate (RR) of fresh‐cut produce, towards the design of a suitable modified atmosphere packaging (MAP) system, requires an adequate mathematical model for prediction of RR as a function of both time and temperature. This study investigated the effect of temperature (5, 10, and 15 °C) and storage time (1 to 5 d) on the RR ( and ) of 2 pomegranate cultivars (cv. ``Acco'' and ``Herskawitz'') fresh arils. and were 3 to 4 folds significantly higher with increased temperature from 5 to 15 °C and were within the range of 2.51 to 7.59 mL/kg h and 2.72 to 9.01 mL/kg h, respectively, for both cultivars. At 15 °C increased significantly from 8.4 to 25.96 mL/kg h from day 1 to 5, respectively, while at 5 °C changed from 2.9 to 2.05 mL/kg h from day 1 to 5. Temperature had the greatest influence on RR and the interaction of time and temperature also significantly affected and . The respiratory quotient (RQ) estimated by linear regression was 0.98 at 95% significant level. The dependence of RR on temperature and time was accurately described with a combination of an Arrhenius‐type and power equation model for and of fresh pomegranate arils.

Practical application:  Predicting the respiration of fresh and fresh‐cut produce is important in designing postharvest handling systems. Mathematical models to predict respiration rates of pomegranate fresh arils have been developed taking into account the effects of storage time and temperature. These models have practical application in designing modified atmosphere packaging to maintain quality and shelf life of pomegranate arils.
Application of Principal Component Analysis and Spectral Angle Mapper in the Mapping of Hydrothermal Alteration in the Jebal–Barez Area, Southeastern Iran
Authors: HONARMAND Mehdi , RANJBAR Hojjatollah , SHAHABPOUR Jamshid
Published: March 2012

The southeastern part of the central Iranian Cenozoic magmatic belt contains many areas with copper mineralization. In an analysis of this region, we used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Enhanced Thematic Mapper plus (ETM+) images to map the distribution of hydrothermally altered rocks, based on their mineral assemblages. The spectral measurements, based on the field samples and satellite‐image‐derived spectra, show dominantly Al–OH (sericite and clays) and Fe–O absorption features in the visible–near infrared to shortwave infrared regions of the spectrum. Silica–bearing rocks, as well as silicic alteration, show an intense Si–O vibrational feature in the thermal infrared wavelength region. We analyzed ASTER/ETM+ images, performed a directed principal component analysis, and used spectral angle mapper to map areas of hydrothermal alteration and iron oxide/hydroxide minerals. The individual principal component images compiled by directed principal component analysis reveal the distribution of individual alteration minerals such as sericite, kaolinite, chlorite, epidote, and quartz. The best results, in terms of mapping the distribution of alteration, were obtained using the spectral angle mapper method. The altered areas were then sampled and the samples subjected to X–ray diffraction analysis, spectral analysis, and thin sections were observed under a microscope. Field observations reveal that more than 98% of the known copper mineralization occurs within the interpreted alteration areas. The present results indicate the great potential of ASTER and ETM+ data for mapping the distribution of alteration and exploring for copper mineralization in areas with a similar climate and geological setting to those of the present study.
The Arinem Te‐Bearing Gold‐Silver‐Base Metal Deposit, West Java, Indonesia
Authors: YUNINGSIH Euis T. , MATSUEDA Hiroharu , SETYARAHARJA Eko P. , ROSANA Mega F.
Published: March 2012

The vein system in the Arinem area is a gold‐silver‐base metal deposit of Late Miocene (8.8–9.4 Ma) age located in the southwestern part of Java Island, Indonesia. The mineralization in the area is represented by the Arinem vein with a total length of about 5900 m, with a vertical extent up to 575 m, with other associated veins such as Bantarhuni and Halimun. The Arinem vein is hosted by andesitic tuff, breccia, and lava of the Oligocene–Middle Miocene Jampang Formation (23–11.6 Ma) and overlain unconformably by Pliocene–Pleistocene volcanic rocks composed of andesitic‐basaltic tuff, tuff breccia and lavas. The inferred reserve is approximately 2 million tons at 5.7 g t−1 gold and 41.5 g t−1 silver at a cut‐off of 4 g t−1 Au, which equates to approximately 12.5t of Au and 91.4t of Ag. The ore mineral assemblage of the Arinem vein consists of sphalerite, galena, chalcopyrite, pyrite, marcasite, and arsenopyrite with small amounts of pyrrhotite, argentite, electrum, bornite, hessite, tetradymite, altaite, petzite, stutzite, hematite, enargite, tennantite, chalcocite, and covellite. These ore minerals occur in quartz with colloform, crustiform, comb, vuggy, massive, brecciated, bladed and calcedonic textures and sulfide veins. A pervasive quartz–illite–pyrite alteration zone encloses the quartz and sulfide veins and is associated with veinlets of quartz–calcite–pyrite. This alteration zone is enveloped by smectite–illite–kaolinite–quartz–pyrite alteration, which grades into a chlorite–smectite–kaolinite–calcite–pyrite zone. Early stage mineralization (stage I) of vuggy–massive–banded crystalline quartz‐sulfide was followed by middle stage (stage II) of banded–brecciated–massive sulfide‐quartz and then by last stage (stage III) of massive‐crystalline barren quartz. The temperature of the mineralization, estimated from fluid inclusion microthermometry in quartz ranges from 157 to 325°C, whereas the temperatures indicated by fluid inclusions from sphalerite and calcite range from 153 to 218 and 140 to 217°C, respectively. The mineralizing fluid is dilute, with a salinity <4.3 wt% NaCl equiv. The ore‐mineral assemblage and paragenesis of the Arinem vein is characteristically of a low sulfidation epithermal system with indication of high sulfidation overprinted at stage II. Boiling is probably the main control for the gold solubility and precipitation of gold occurred during cooling in stage I mineralization.
Genesis of the Xuebaoding W–Sn–Be Crystal Deposits in Southwest China: Evidence from Fluid Inclusions, Stable Isotopes and Ore Elements
Authors: LIU Yan , DENG Jun , SHI Guanghai , SUN Xiang , YANG Liqiang
Published: March 2012

The Xuebaoding crystal deposit, located in northern Longmenshan, Sichuan Province, China, is well known for producing coarse‐grained crystals of scheelite, beryl, cassiterite, fluorite and other minerals. The orebody occurs between the Pankou and Pukouling granites, and a typical ore vein is divided into three parts: muscovite and beryl within granite (Part I); beryl, cassiterite and muscovite in the host transition from granite to marble (Part II); and the main mineralization part, an assemblage of beryl, cassiterite, scheelite, fluorite, apatite and needle‐like tourmaline within marble (Part III). No evidence of crosscutting or overlapping of these ore veins by others suggests that the orebody was formed by single fluid activity. The contents of Be, W, Sn, Li, Cs, Rb, B, and F in the Pankou and Pukouling granites are similar to those of the granites that host Nanling W–Sn deposits. The calculated isotopic compositions of beryl, scheelite and cassiterite (δD, −69.3‰ to −107.2‰ and δ18OH2O, 8.2‰ to 15.0‰) indicate that the ore‐forming fluids were mainly composed of magmatic water with minor meteoric water and CO2 derived from decarbonation of marble. Primary fluid inclusions are CO2− CH4+ H2O ± CO2 (vapor), with or without clathrates and halites. We estimate the fluid trapping condition at T = 220 to 360°C and P > 0.9 kbar.

Fluid inclusions are rich in H2O, F‐ and Cl‐. Evidence for fluid‐phase immiscibility during mineralization includes variable L/V ratios in the inclusions and inclusions containing different phase proportions. Fluid immiscibility may have been induced by the pressure released by extension joints, thereby facilitating the mineralization found in Part III. Based on the geochemical data, geological occurrence, and fluid inclusion studies, we hypothesize that the coarse‐grained crystals were formed by: (i) the high content of ore elements and volatile elements such as F in ore‐forming fluids; (ii) occurrence of fluid immiscibility and Ca‐bearing minerals after wall rock transition from granite to marble making the ore elements deposit completely; (iii) pure host marble as host rock without impure elements such as Fe; and (iv) sufficient space in ore veins to allow growth.
Radioelement Mapping and Environmental Monitoring of Surface Deposits using Ground Gamma Ray Spectrometry of the Area Adjacent to El‐Ramlah Village, Southwestern Sinai, Egypt
Authors: ABOELKHAIR Hatem , RABEI Mostafa
Published: March 2012

A ground‐based gamma‐ray survey has been performed in the area close to El‐Ramlah village, southwestern Sinai, Egypt, using a GS‐512 spectrometer. The main objective of this survey was to delineate radioactive anomalies within the surface of the study area and to identify the environmental effects of natural radioelements on the new inhabitants, Bedouins, who live in the recently built village in this region of the Sinai Peninsula. The results show that the maximum radioactivity of the total count component (T.C.) was about 15.7Ur at the northern part of the study area. The average radioelements concentration were 0.4% for potassium, 1.6 ppm for equivalent uranium and 4.5 ppm for equivalent thorium. To identify and map the environmental effects of the concentration of these radioelements on El‐Ramlah village, measurements of potassium (K%), equivalent uranium (eU) and equivalent thorium (eTh) were converted into an equivalent dose rate. The results illustrate that, the levels of effective dose rate of the natural radioactivity of the area of study remains in the safe range without any harm to living organisms, and it stays within the maximum permissible radiation dose rate (1.0 mSv y−1) recommended by the International Commission of Radiological Protection.
Antidiabetic and antihyperlipidemic effects of the stem of Musa sapientum Linn. in streptozotocin‐induced diabetic rats
Authors: Dikshit Piyush , Shukla Kirtikar , Tyagi Mool Kumar , Garg Piyush , Gambhir Jasvindar K. , Shukla Rimi
Published: March 2012

Background:  Musa sapientum Linn. is a herbaceous plant of the Musaceae family. It has been used in India for the treatment of gastric ulcer, hypertension, diarrhea, dysentery, and diabetes. The antidiabetic effect of the fruit, root, and flower has been demonstrated. The aim of the present study was to assess the antidiabetic and antihyperlipidemic effects of the stem of M. sapientum Linn.

Methods:  Diabetes was induced in rats by streptozotocin injection (45 mg/kg, i.p.). Diabetic rats were treated for 2 weeks with different doses of lyophilized stem juice of M. sapientum Linn. (25, 50, and 100 mg/kg) to select the most effective dose. The effects of 4 weeks treatment with this dose (50 mg/kg) on fasting and postprandial plasma glucose (FPG, PPG) levels, body weight, lipid profile, HbA1c, insulin, liver enzymes (i.e. glucokinase, glucose‐6‐phosphatase and 3‐hydroxy‐3‐methylglutaryl coenzyme A [HMG‐CoA] reductase) and muscle and liver glycogen were evaluated.

Results:  The most effective dose of lyophilized stem juice of M. sapientum Linn. was 50 mg/kg. Four weeks treatment with this dose resulted in significant decreases in FPG and PPG (P < 0.05). Serum insulin increased (P < 0.05) whereas HbA1c decreased (P < 0.05). Diabetes‐induced changes to the lipid profile, muscle and liver glycogen, and enzyme activity (i.e. glucokinase, glucose‐6‐phosphatase, and HMG‐CoA reductase) were restored near to normal levels (P < 0.05).

Conclusion:  Diabetic rats responded favorably to treatment with lyophilized stem juice of M. sapientum Linn., which exhibits antidiabetic and antihyperlipidemic effects.
Pathophysiology of Overactive Bladder
Authors: MENG En , LIN Wei‐Yu , LEE Wei‐Chia , CHUANG Yao‐Chi
Published: March 2012

Overactive bladder syndrome (OAB), characterized by urinary frequency, nocturia and urgency with or without incontinence, is a widespread medical condition with significant impact on quality of life. Three main factors have been proposed regarding the cause of OAB: myogenic, neurogenic and urotheliogenic. Disturbance of any of the three factors or a combination of these factors can attribute to OAB. Metabolic derangement, bladder outlet obstruction and inflammation can increase the excitability of nerve, detrusor muscle and alter the sensory and barrier functions of the urothelium. The detection of proteins in the urine such as NGF, PGE2, and proinflammatory chemokines may advance our understanding of the pathophysiology of OAB and offer novel diagnostic biomarkers of OAB.
Association between Metabolic Syndrome and Lower Urinary Tract Symptoms: Evidences from Epidemiological Studies
Authors: TAI Huai‐Ching , YU Hong‐Jeng
Published: March 2012

Metabolic syndrome (MS) and lower urinary tract symptoms (LUTS) are both highly prevalent problems of public health in the modern era. MS has been demonstrated to increase the risks for developing cardiovascular, kidney and liver diseases, and recent epidemiological evidences have indicated a possible link between MS and urological diseases, such as erectile dysfunction (ED) in men and LUTS in both sexes. The relationship between MS and LUTS was first described by Hammarsten et al. and concluded that men with MS risk factors had a larger prostate volume and a faster growth rate. Several consequent studies have also supported the association between MS and LUTS suggestive of benign prostatic hyperplasia (BPH) in men. However, studies have reported that the female lower urinary tract was affected by the components of MS as well. However, two recent surveys did not find a significant association between MS and LUTS. To date, this association remains unclear, and future longitudinal studies are needed to further clarify the controversy.
Outcome Measurement of Overactive Bladder
Authors: LIEN Chi‐Shun , Chieh‐Lung Chou Eric
Published: March 2012

Overactive bladder (OAB) is a common disease. The diagnosis of OAB is based on its symptoms without physiological markers of disease activity. Frequently used assessment methods for OAB include frequency volume chart; urodynamic studies; patient‐reported outcomes questionnaires, such as the Overactive Bladder Questionnaire, King's Health Questionnaire, patient perception of bladder conditions; and OAB symptom score. The severity of OAB and degree of improvement after treatment can be obtained by comprehensive evaluation. However, a consensus of which evaluations should be used to define the severity of OAB is still lacking. We expect a proper OAB assessment with universal acceptance in the future.
Cold Stress and Urinary Frequency
Authors: ISHIZUKA Osamu , IMAMURA Tetsuya , NISHIZAWA Osamu
Published: March 2012

There have been few studies regarding the onset of urinary sensations and frequent urination induced by sudden whole‐body cooling. In this article, we review the relationship between cold stress and urinary frequency based mainly on our previous studies. A recent study showed that cold stress induces bladder overactivity in conscious rats, and these effects were mediated, at least in part, byα1A‐adrenergic receptor (AR) andα1D‐AR. Another study suggested that the resiniferatoxin‐sensitive nerves present in the urinary bladder may also be involved in the regulation of detrusor activity associated with cold stress. The mammalian transient receptor potential (TRP) channel family consists of 28 channels subdivided into five different classes: TRPV (vanilloid), TRPC (canonical), TRPM (melastatin), TRPML (mucolipin), and TRPA (ankyrin). TRP channels function as multifunctional sensors at the cellular level. They can be activated by physical (voltage, heat, cold, mechanical stress) or chemical stimuli and binding of specific ligands. In 2002, it was reported that a nonselective cation channel, TRPM8, could be activated by both menthol and thermal stimuli (8–28 °C). We demonstrated the presence of TRPM8 in the skin from the legs and back of rats by immunofluorescence staining and that stimulation of this receptor by menthol causes urinary frequency. There have been other reports demonstrating roles of TRPM8 not related to its thermosensory function. Further studies are needed to clarify the mechanism of cold stress‐induced urinary frequency, and the roles of TRPM8 in the micturition control system.
Effects of Chronic Hyperlipidemia on Lower Urinary Tract Function—Bladder Dysfunction in Myocardial Infarction‐Prone Watanabe Heritable Hyperlipidemic Rabbits
Authors: YOSHIDA Masaki , KUDOH Junzo , MASUNAGA Koichi , NAGATA Takashi , SHIOMI Masashi
Published: March 2012

To evaluate the effects of chronic hyperlipidemia on bladder function, we examined the functional and histological changes of the bladder in myocardial infarction‐prone Watanabe heritable hyperlipidemic (WHHL‐MI) rabbits. Two age groups of WHHL‐MI rabbits (6–12 months old, young WHHL‐MI rabbits; and 20–24 months old, old WHHL‐MI rabbits group) and the sex‐ and age‐matched control rabbits were prepared. Bladder functions were evaluated using frequency volume charts and cystometrograms, and functional experiments using isolated bladder specimens. Histological studies of bladder were performed with HE staining and immunohistochemical staining with mouse monoclonal S‐100 protein antibodies and sheep polyclonal calcitonin gene‐related peptide (CGRP) antibodies. In cystometrograms, it has been demonstrated that WHHL‐MI rabbits showed significantly shorter micturition interval, smaller voided volume with non‐voiding contractions compared to control. There was no significant difference in voiding pressure between young WHHL‐MI and control rabbits. However, old WHHL‐MI rabbits showed a lower voiding pressure than control rabbits. The functional experiments revealed that carbachol‐ and electrical field stimulation (EFS)‐induced contractile responses of isolated bladder strips were significantly increased in young WHHL‐MI rabbits than in control rabbits. However, in the bladder strips of old WHHL‐MI rabbits, decreased responses to carbachol and EFS were observed. In WHHL‐MI rabbits, bladder urothelium became thinner, smooth muscle area decreased and connective tissue area increased gradually with aging. A significant decrease in S‐100 protein‐positive neurons, and an increased number of CGRP‐positive neurons were observed in both young and old WHHL‐MI rabbits. The data demonstrated that there were differences in bladder dysfunction between young and old WHHL‐MI rabbits. Old WHHL‐MI rabbits showed detrusor hyperactivity with impaired contraction. This study may demonstrate the developmental mechanism of bladder dysfunction in chronic hyperlipidemia.
APPLYING A GENETIC ALGORITHM TO INTERNATIONAL DIVERSIFICATION OF EQUITY PORTFOLIOS: A SOUTH AFRICAN INVESTOR PERSPECTIVE
Authors: KABUNDI ALAIN , MWAMBA JOHN MUTEBA
Published: March 2012

This paper uses the genetic algorithm (GA) approach to generate a portfolio optimisation scenario of a South African investor who seeks to maximise return from investing in S&P500, FTSE100, NASDAQ, DOWJONES, CAC40 and the DAX from January 1, 2005, to January 31, 2008, but facing exchange rate risk. The GA searches for the optimal solution in the entire set of financial constraints without looking for partial derivatives of the utility function. Whereas most financial problems require a non‐linear and time‐varying model, the GA, with its survival principle of offspring chromosomes, is better suited to this type of problem than local optimisation methods. The performance of the GA is compared with two non‐linear models, namely the quadratic mean‐variance (QMV), which maximises the portfolio mean‐variance, and the quadratic variance minimisation (QVM), which minimises the portfolio variance. The results show that neither the QMV nor the QVM takes into account the domestic investors' risk attitude towards investing in foreign equities and therefore does not provide any international diversification benefits. In addition, the bootstrapping scenario of 10,000 simulations reveals that neither the QMV nor the QVM outperforms the GA in terms of Sharpe ratio and flexibility in dealing with investors' risk attitude towards investing in foreign equities denominated in foreign currencies.
BEHAVIOURAL RESPONSE TO PLASTIC BAG LEGISLATION IN BOTSWANA
Authors: DIKGANG JOHANE , VISSER MARTINE
Published: March 2012

This paper investigates the use of charges and standards in dealing with a common externality, plastic litter from shopping bags in Botswana. The country passed a plastic bag legislation (effective 2007) to curb the plastic bag demand. Uniquely, the act does not stipulate the amount that the retailers had to charge for plastic bags, they, independently from one another, set different prices. We assessed the environmental effectiveness and efficiency of the plastic bag legislation by analysing consumers' sensitivity to the improvement of the plastic bag and related price charges. The introduction of the plastic bag legislation led to a significant decline in the consumption of plastic bags per 1,000 Botswana pulas of shopping. The partial success of the charges levied in Botswana was due to the constantly high prices of the bags.
Metabolic encephalopathies in foals – pay attention to the serum biochemistry panel!
Authors: Johnson A. L. , Gilsenan W. F. , Palmer J. E.
Published: March 2012

Careful assessment of the biochemistry panel and familiarity with normal biochemistry values for neonatal foals is imperative in the workup of any critically ill neonate, particularly those with neurological signs. The importance of rapidity of change compared to the absolute value of the biochemical abnormality must be emphasised. Serial biochemical panels ideally assist in assessing rapidity of change. Many foals can have severe biochemical derangements in the absence of seizures. Identifying values that are significantly out of range should spur immediate therapy to correct them and potentially additional diagnostic testing to determine the cause of the abnormalities. A temporal relationship between correction of biochemical abnormalities and resolution of seizures and encephalopathic signs supports causation.
Langlands duality and global Springer theory
Authors: Yun Zhiwei
Published: March 2012

We compare the cohomology of (parabolic) Hitchin fibers for Langlands dual groups G and G∨. The comparison theorem fits in the framework of the global Springer theory developed by the author. We prove that the stable parts of the parabolic Hitchin complexes for Langlands dual group are naturally isomorphic after passing to the associated graded of the perverse filtration. Moreover, this isomorphism intertwines the global Springer action on one hand and Chern class action on the other. Our result is inspired by the mirror symmetric viewpoint of geometric Langlands duality. Compared to the pioneer work in this subject by T. Hausel and M. Thaddeus, R. Donagi and T. Pantev, and N. Hitchin, our result is valid for more general singular fibers. The proof relies on a variant of Ngô’s support theorem, which is a key point in the proof of the Fundamental Lemma.
Quantifying residual finiteness of arithmetic groups
Authors: Bou-Rabee Khalid , Kaletha Tasho
Published: March 2012

The normal residual finiteness growth of a group quantifies how well approximated the group is by its finite quotients. We show that any S-arithmetic subgroup of a higher rank Chevalley group G has normal residual finiteness growth ndim (G).
Evaluation of Porous Ni-YSZ Cermets With Ni Content of 0–30 Vol. % as Insulating Substrates for Segmented-in-Series Tubular Solid Oxide Fuel Cells
Authors: Wang Zhenwei , Mori Masashi , Itoh Takanori
Published: March 2012

Nickel was added to a substrate composed of porous Y2O3-stabilized ZrO2 (YSZ) in order to minimize anode damage during redox cycling in segmented-in-series tubular solid oxide fuel cells (SOFCs) with YSZ electrolytes. In this study, the electrical insulating and thermal properties of these materials were evaluated for their suitability as substrates in the tubular SOFCs. When the Ni content was ≤20 vol. %, the porous cermets showed an electrical resistance of ≤67 Ω cm at 900 °C, indicating that the theoretical open circuit voltage for the tubular SOFCs could be achieved. However, the cermet with 20 vol. % Ni was destroyed during the first heating cycle in air because of large isothermal expansion. However, no obvious cracks were observed for cermets with ≤10 vol. % Ni. From the viewpoint of thermogravimetric measurement, this suggests that there are two redox mechanisms for Ni particles in the substrate. They were reduced/oxidized by both the gases and the oxide-ions passing through the YSZ framework. Based on the insulating and thermal properties of the substrate, the optimal composition was found to be approximately 10 vol. % Ni.
A Transient Fuel Cell Model to Simulate HTPEM Fuel Cell Impedance Spectra
Authors: Vang Jakob Rabjerg , Andreasen Søren Juhl , Kær Søren Knudsen
Published: March 2012

This paper presents a spatially resolved transient fuel cell model applied to the simulation of high temperature PEM fuel cell impedance spectra. The model is developed using a 2D finite volume method approach. The model is resolved along the channel and across the membrane. The model considers diffusion of cathode gas species in gas diffusion layers and catalyst layer, transport of protons in the membrane and the catalyst layers, and double layer capacitive effects in the catalyst layers. The model has been fitted simultaneously to a polarization curve and to an impedance spectrum recorded in the laboratory. A simultaneous fit to both curves is not achieved. In order to investigate the effects of the fitting parameters on the simulation results, a parameter variation study is carried out. It is concluded that some of the fitting parameters assume values which are not realistic. In order to remedy this, phenomena neglected in this version of the model must be incorporated in future versions.
Crystal Structure and Anomalous Sintering Behavior of (Sr0.7La0.3)1−xTiO3+δ Perovskites (0 ≤ x ≤ 0.12) Synthesized by the Pechini Method
Authors: Mori Masashi , Nakamura Kaoru , Itoh Takanori
Published: March 2012

The crystal structure, phase relationship and sintering characteristics of (Sr0.7La0.3)1−xTiO3+δ perovskites (0 ≤ x ≤ 0.12) have been studied using the Pechini method. High-temperature neutron diffraction analysis showed that (Sr0.7La0.3)TiO3+δ has an orthorhombic structure at room temperature and a cubic structure at 450 °C. (Sr0.7La0.3)0.88TiO3+δ showed a single perovskite phase and other samples with an A-site deficiency of 0 ≤ x ≤ 0.08 included secondary Ruddlesden-Popper phases. Sintering characteristics improved as the A-site deficiency increased and it was found that during sintering, (Sr0.7La0.3)0.88TiO3+δ expanded anomalously between 1400 °C and 1500 °C and for holding times between 0 h and 10 h at 1400 °C and 1500 °C. Additionally, observation of the samples by scanning electron microscopy showed that this expansion was caused by pore formation within the samples. All the samples showed a weight decrease at temperatures ≥1000 °C and the temperature at which oxygen release began rose as the A-site deficiency increased. The release of oxygen is likely to be related to pore formation.
Electrochemical Behavior of Metal-Supported SOFCs Under High Fuel Utilization and Their Durability
Authors: Antepara I. , Diaz L. , Rivas M. , Otaegi L. , Gomez N. , Villarreal I. , Laresgoiti A.
Published: March 2012

The aim of this project was to study whether the oxidation resistance of cells is affected while working under high fuel utilization. A previous study measured the weak oxidation resistance for very porous samples (measured porosity ∼ 70%) in H2 with high H2O content (over 50%) in the interval from 600 to 800 °C. Thus, additional tests were carried out with cells. Crofer22APU-supported solid oxide fuel cells (SOFCs) were produced by scalable cost competitive routes. One of the highly porous cells (calculated porosity 45%) was run under high fuel utilization conditions (calculated fuel utilization 56%), and a further two in H2-50%H2O. Another cell, with low porosity (calculated porosity 20%), was kept working in the same H2-50%H2O atmosphere for many hours. Durability tests with cells of different porosities confirmed that this is the main variable concerning degradation issues while working under high fuel utilization.
Modeling and Experiments of Voltage Transients of Polymer Electrolyte Membrane Fuel Cells With the Dead-Ended Anode
Authors: Yesilyurt Serhat , Siegel Jason B. , Stefanopoulou Anna G.
Published: March 2012

Operation of PEM fuel cells (PEMFC) with the dead-ended anode (DEA) leads to severe voltage transients due to accumulation of nitrogen, water vapor and liquid water in the anode channels and the gas diffusion layer (GDL). Accumulation of nitrogen causes a large voltage transient with a characteristic profile whereas the amount of water vapor in the anode is limited by the saturation pressure, and the liquid water takes up very small volume at the bottom of the anode channels in the case of downward orientation of the gravity. We present a transient 1D along-the-channel model of PEMFCs operating with periodically-purged DEA channels. In the model, transport of species is modeled by the Maxwell-Stefan equations coupled with constraint equations for the cell voltage. A simple resistance model is used for the permeance of nitrogen and transport of water through the membrane. Simulation results agree very well with experimental results for voltage transients of the PEMFC operating with the DEA. In order to emphasize the effect of nitrogen accumulation in the anode, we present experimentally obtained cell voltage measurements during DEA transients when the cathode is supplied with pure oxygen. In the absence of nitrogen in the cathode, voltage remained almost constant throughout the transient. The model is used to demonstrate the effect of oxygen-to-nitrogen feed ratio in the cathode on the voltage transient behavior for different load currents. Lastly, the effect of small leaks from the anode exit on the voltage transient is studied: even for leak rates as low as 10 ml/h, nitrogen accumulation in the anode channels is alleviated and the cell voltage remained almost constant throughout the transient according to the results.
Highlighting of Critical Experimental Data for SOFC Modeling That is Missing From the Literature and Potential of N-IR Thermography for SOFC Study
Authors: Lawlor V.
Published: March 2012

Within the following brief is the researched conclusion that there is a lack of fundamental experimental data available to the scientific community detailing the temperature profile through the cathode/electrolyte/anode assembly section of Solid Oxide Fuel Cells (SOFC). Within these electrochemical reaction driving deceives, heat may be generated and diminished by several means. For example, heat is generally considered to be generated locally; as a result of the reactor’s fundamental operation. Furthermore, heat is generally considered to be generated and/or diminished, depending on the reforming method used, when the anode executes hydrocarbon fuel reformation. Not continually developing and/or utilizing novel experimental techniques, often developed for other fields, in order to provide fundamentally elucidating experimental data regarding SOFC operation is counter-intuitive. To date, the high temperature fuel cell field has not fully adopted the potential of thermography in order to study SOFC internal operation and indeed material characterization. This may be caused by the recent rapid development of the technology, which has reduced its cost while increasing its scope. This technical brief aims to highlight missing experimental data and suggest a technology and approach that may be able to address the issue.
Experimental and Numerical Evaluation of the Bypass Flow in a Catalytic Plate Reactor for Hydrogen Production
Authors: Sigurdsson Haftor O. , Kær Søren K.
Published: March 2012

Numerical and experimental study is performed to evaluate the reactant bypass flow in a catalytic plate reactor with a coated wire mesh catalyst for steam reforming of methane for hydrogen generation. Bypass of unconverted methane is evaluated under different wire mesh catalyst width to reactor duct width ratios, the results show that altering this ratio from 0.98 to 0.96 results in an increase in bypass mass flow of 22%. Effect of catalytic wire mesh flow resistance on bypass flow has also been investigated and results show increased bypass flow as catalytic wire mesh flow resistance increases. The numerical results are in good agreement with experimental data. The study improves the understanding of the underlying transport phenomena in these reactors and shows that the flow maldistribution in a catalytic plate reactor using a coated wire mesh has to be considered.
Thermodynamic Models for the Temperature and Pressure Variations Within Adiabatic Caverns of Compressed Air Energy Storage Plants
Authors: Kushnir R. , Ullmann A. , Dayan A.
Published: March 2012

The temperature and pressure variation limits within the cavern of a compressed air energy storage (CAES) plant affect the compressor and turbine works, the required fuel consumption and therefore the overall plant performance. In the present work, the thermodynamic response of adiabatic cavern reservoirs to charge/discharge cycles of CAES plants are studied. Solutions for the air cavern temperature and pressure variations were derived from the mass and energy conservation equations, and applied to three different gas state equations, namely, ideal, real, and a self-developed simplified gas models. Sensitivity analyses were conducted to identify the dominant parameters that affect the storage temperature and pressure fluctuations. It is demonstrated that a simplified gas model can adequately represent the air thermodynamic properties. The stored air maximal to minimal temperature and pressure ratios were found to depend primarily on, both the ratio of the injected to the initial cavern air mass, and the reservoir mean pressure. The results also indicate that the storage volume is highly dependent on the air maximum to minimum pressure ratio. Its value should preferably be in between 1.2 and 1.8, where the exact selection should account for design and economic criteria.
Energy Recovery in Passenger Cars
Authors: Boretti Alberto A.
Published: March 2012

The turbocharged direct injection stoichiometric spark ignition gasoline engine has less than diesel full load brake engine thermal efficiencies and much larger than diesel penalties in brake engine thermal efficiencies reducing the load. This engine has, however, a much better power density, and therefore may operate at much higher brake mean effective pressure (BMEP) values over driving cycles thus reducing the fuel economy penalty of the vehicle. This engine also has the advantage of the very well developed three way catalytic (TWC) converter after treatment to meet future emission regulations. Replacement of fossil gasoline with renewable gasoline-like fuels has major advantages. Ethanol and methanol have larger than gasoline resistance to knock and heat of vaporization, and this ultimately translates in larger than gasoline compression ratio and boost pressure and spark advances closer to maximum brake torque producing better efficiencies both full and part load. For the specific of these novel turbocharged direct injection stoichiometric spark ignition renewable gasoline-like engines coupled to a hybrid-electric power train, the paper considers the option to boost the total fuel conversion efficiency generating both mechanical and electric energy. When the internal combustion engine operates, significant fuel energy is lost in both the exhaust and the coolant. Part of this energy is recovered here by using organic Rankine cycle (ORC) systems fitted to both the exhaust and the coolant, with their expanders driving generators charging the battery of the car. The exhaust and the coolant organic Rankine cycle are effective in increasing the amount of fuel energy converted in usable power over the full range of loads and speeds. The organic Rankine cycle system fitted on the exhaust permits to increase the usable power versus the fuel energy flow rate of a 3.4% on average, with top improvements up to 6.4%. The system is effective particularly at high speeds and loads. The organic Rankine cycle system fitted on the coolant permits to increase the usable power versus the fuel energy flow rate of a 1.7% on average, with top improvements up to 2.8%. The system is effective particularly at low speeds and loads. The two combined organic Rankine cycle systems permit to increase the usable power versus the fuel energy flow rate of a 5.1% on average, with top improvements up to 8.2%.
Aerodynamic Performance of a Small Horizontal Axis Wind Turbine
Authors: Refan Maryam , Hangan Horia
Published: March 2012

The aerodynamic performance of an upwind, three-bladed, small horizontal axis wind turbine (HAWT) rotor of 2.2 m in diameter was investigated experimentally and theoretically in order to assess the applicability of the blade element momentum (BEM) theory for modeling the rotor performance for the case of small HAWTs. The wind turbine has been tested in the low and high speed sections of the Boundary Layer Wind Tunnel 2 (BLWT2) at the University of Western Ontario (UWO) in order to determine the power curve over a wide range of wind speeds. Afterward, the BEM theory has been implemented to evaluate the rotor performance and to investigate three-dimensionality effects on power prediction by the theory. Comparison between the theoretical and experimental results shows that the overall prediction of the theory is within an acceptable range of accuracy. However, the BEM theory prediction for the case of small wind turbines is not as accurate as the prediction for larger wind turbines.
Performance Optimization of Abrasive Fluid Jet for Completion and Stimulation of Oil and Gas Wells
Authors: Gupta Anuj
Published: March 2012

This paper provides an overview of the development and optimization of abrasive-slurry-jet methods for completion and stimulation applications. Abrasive particles added to the fluid dramatically reduced the system pressure requirements. The paper discusses the technical capabilities of cutting through various materials and formations and also discusses improvements and proven applications. Abrasive fluid-jet systems are capable of cutting through rocks of all types, and with greater location control that is not susceptible to the geologically induced deviations encountered with mechanical methods. Abrasive fluid-jets drill rock through the erosion induced by very small particles which individually remove only small fragments but are in such numbers that the drilling rate is at or above that of conventional tools. The particles are powered by the velocity of the supporting fluid, generated in turn by pumps on the surface. The cutting occurs ahead of the nozzle body allowing the nozzle assembly to be fed in the tunnel to create drain-holes. Fluid-jet methods have the potential of improving completion and stimulation efficiency in heterogeneous formations such as fractured and/or vuggy carbonate reservoirs. Application for completion, stimulation and, even, well/platform abandonment has been successful.
Low Field in the Vaned Diffuser of a Centrifugal Pump at Different Vane Setting Angles
Authors: Gaetani P. , Boccazzi A. , Sala R.
Published: March 2012

Particle image velocimetry (2D-PIV) has been used for the investigation of the time and phase-averaged flow field inside the vaned diffuser of a centrifugal pump operating at the best efficiency point (BEP). Pump performances and the diffuser flow field were analyzed for three different vane setting angles. It was evidenced that flow coefficient at the best efficiency point decreases with the diffuser setting angle reduction. From 2D-PIV measurements in five different blade to blade planes, spanwise averaged flow angles and velocity distribution were computed. It was evidenced an influence of the diffuser setting angle on the spanwise distribution of the flow rate and of the absolute mass averaged flow angle at impeller discharge. An overturning at the diffuser discharge was also evidenced for the two highest setting angles. 2D-PIV flow fields are presented in three different pseudosecondary planes in order to enlighten the cross flows affecting the diffuser flow field.
Comparison Between Numerical and Experimental Results of Airflow Distribution in Diffuser Based Data Center
Authors: Jian Qifei , Wang Qiaoli , Wang Haoting , Zuo Zheng
Published: March 2012

This paper studies the flow and temperature patterns in an overhead diffuser based data center. In-situ measurements of the data center were carried out to validate a mathematic model for predicting the effect of different air distribution systems. With the measured data of temperatures and airflow velocities, the mathematic model is constructed using a commercial Computational Fluid Dynamics (CFD) software and experimental data to present a comparison between test results and numerical simulations. The area of the data center is 311 square meters and the heat load of the equipment is 320~360 watt per square meter. In-situ temperatures and humidity of the data center were measured with an Automatic Temperature and Humidity measuring instrument, whose error is ±0.5 °C. The discrepancy of the temperature and velocity between the numerical and experimental results were within ±2.3 °C and ±1.8 m/s, respectively. In addition, analysis shows that changing the volume flow rate of the cold air delivered to some diffusers can optimize the temperature field and thereby save the energy.
Thermal Energy Storage Thermal Response Model With Application to Thermal Management of High Power-Density Hand-Held Electronics
Authors: Wirtz R. A. , Swanson K. , Yaquinto M.
Published: March 2012

An important design objective that is unique to hand-held units is the need to constrain two temperatures: the maximum temperature of the electronic components and the maximum skin temperature of the hand-held unit. The present work identifies and evaluates, through parametric modeling and experiments, the passive thermal energy storage volume characteristics and phase change material composite properties that are most suitable for thermal control of small form-factor, high power-density, hand-held electronics. A one-dimensional transient analytical model, based on an integral heat balance, is formulated and benchmarked. The model accurately simulates the heat storage/recovery process in a semi-infinite, “dry” phase change material slab. Dimensional analysis identifies the time and temperature metrics and nondimensional parameters that describe the heat storage/release process. Parametric analysis illustrates how changes in these nondimensional parameters affect thermal energy storage volume thermal response.
Nonlinear Control of Hyperchaotic System, Lie Derivative, and State Space Linearization
Authors: Ray Anirban , RoyChowdhury A. , Mukherjee Indranil
Published: March 2012

State space linearization using the concept of Brunovsky form and Lie derivative is applied to the case of a Hyperchaotic Lorentz System. It is observed that the necessary and sufficient conditions can be satisfied, the analytic form of the controller ‘u’ and the final form of the linearized equations can be obtained. Numerical simulation is used to ascertain the feasibility of the procedure in practice. It may be added that the case of an ordinary Lorentz equation is distinctively different as the controller is to be added in a different manner. The most important aspect of the present analysis is that the controller can be determined and not chosen ad hoc.