bluuebunny/crossref_metadata_2025 huggingface dataset:
WHO SHOULD BE GIVEN MORE FOREIGN AID?
Authors: Cheng Wenli , Zhang Dingsheng
Published: January 2009

Abstract.   This paper presents a simple model to investigate the effectiveness of foreign aid. It shows that foreign aid is most effective if it is given to a market economy with relatively high transaction efficiency. If transaction efficiency in a market economy is low due to, for instance, bad institutions or policies, then foreign aid will either be largely dissipated as transaction costs or can even lead to retrogression of market activities. In either case, it will be more effective to give foreign aid to poor primitive economies with no developed markets.
J. Cosmet. Sci., 59, 15–32 (January/February 2008) A simple analysis of the changes during evaporation of a commercial emulsion of unknown composition
Authors: Bergamaschi M. M. , Santos O. D. H. , Rocha‐Filho P. A. , Friberg S. E.
Published: January 2009

Synopsis

Optical microscopy and centrifugation were used to observe the structural changes during evaporation of a commercial skin lotion of unknown composition. The degree of evaporation was determined from the changed weight of a microscope slide with the emulsion on a defined area and thickness, the evaporation loss vs. time being measured by a balance under an infrared lamp. The results revealed not only which parts of the emulsion were most prone to evaporation without chemical analysis, but also gave surprising information as to which kind of structures would appear after extensive evaporation. The importance of these changes for the action of a skin lotion is briefly discussed.
J. Cosmet. Sci., 59, 59–69 (January/February 2008) Biological activities of selected peptides: Skin penetration ability of copper complexes with peptides
Authors: Mazurowska L. , Mojski M.
Published: January 2009

Synopsis

This study concerning the permeability through skin barriers of copper complexes with peptides is an important part of the research on their biological activity. The transport of copper complexes through the skin is essential in treatment of dermatological dysfunctions connected to the deficiency of these elements in the skin. During the last several years, a special interest in transepidermal copper delivery has been observed. This is the reason why copper compounds have been used as active compounds in care cosmetics. Yet, the transport process of copper complexes with tripeptides, glycyl‐histidyl‐lysine GHK, or γ‐glutamylcysteinyl‐glycine GSH through the stratum corneum has received very little attention in the literature so far. The penetration ability of GHK‐Cu and GSH‐Cu through the stratum corneum and the influence of the complexes with tripeptide on the copper ion transport process is the key factor in their cosmetic and pharmaceutical activity. The in vitro penetration process was studied in the model system, a Franz diffusion cell with a liposome membrane, where liquid crystalline systems of physicochemical properties similar to the ones of the intercellular cement of stratum corneum were used as a standard model of a skin barrier. The results obtained demonstrated that copper complexes permeate through the membranes modeling the horny lipid layer and showed the influence of peptides on the dynamics of copper ion diffusion.
Vol.42, No.1, pp.36‐39, 2008 Determination of diethylene glycol in toothpaste
Authors: Kamimura M. , Mizuno K. , Kuromi K. , Ueno C. , Kurita H. , Owada K. , Yamamoto M.
Published: January 2009

A rapid and simple method using gas chromatography (GC) for the determination of diethylene glycol (DEG) in toothpaste was developed. DEG in toothpaste was extracted with methanol containing 1,4‐butanediol as the internal standard by using an ultrasonic bath. The centrifuged and filtrated methanol extracts were analyzed by GC on an InertCap 624 capillary column. The recoveries of DEG from toothpaste fortified at the levels of 0.1, 0.5 and 1.0%, were 103.6, 99.9, 99.4%, respectively. The quantitation limit of DEG in toothpaste was 0.05??%. The proposed method could be applied to other cosmetics on the market without any interference. By using this method, DEG was detected the presence in two out of 10 toothpaste samples set to the hotel. This analytical method should be useful for quality control for manufacturers and importers of cosmetics.

Keywords: diethylene glycol (DEG), toothpaste, gas chromatography, capillary column, 1,4‐butanediol, methanol extract, cosmetics, determination, analysis, DEG detection
Patterns of Chronic Multimorbidity in the Elderly Population
Authors: Marengoni Alessandra , Rizzuto Debora , Wang Hui‐Xin , Winblad Bengt , Fratiglioni Laura
Published: January 2009

OBJECTIVES: To describe patterns of comorbidity and multimorbidity in elderly people.

DESIGN: A community‐based survey.

SETTING: Data were gathered from the Kungsholmen Project, a urban, community‐based prospective cohort in Sweden.

PARTICIPANTS: Adults aged 77 and older living in the community and in institutions of the geographically defined Kungsholmen area of Stockholm (N=1,099).

MEASUREMENTS: Diagnoses based on physicians' examinations and supported by hospital records, drug use, and blood samples. Patterns of comorbidity and multimorbidity were evaluated using four analytical approaches: prevalence figures, conditional count, logistic regression models, and cluster analysis.

RESULTS: Visual impairments and heart failure were the diseases with the highest comorbidity (mean 2.9 and 2.6 co‐occurring conditions, respectively), whereas dementia had the lowest (mean 1.4 comorbidities). Heart failure occurred rarely without any comorbidity (0.4%). The observed prevalence of comorbid pairs of conditions exceeded the expected prevalence for several circulatory diseases and for dementia and depression. Logistic regression analyses detected similar comorbid pairs. The cluster analysis revealed five clusters. Two clusters included vascular conditions (circulatory and cardiopulmonary clusters), and another included mental diseases along with musculoskeletal disorders. The last two clusters included only one major disease each (diabetes mellitus and malignancy) together with their most common consequences (visual impairment and anemia, respectively).

CONCLUSION: In persons with multimorbidity, there exists co‐occurrence of diseases beyond chance, which clinicians need to take into account in their daily practice. Some pathological mechanisms behind the identified clusters are well known; others need further clarification to identify possible preventative strategies.
TEM/STEM Observation of ZrC Coating Layer for Advanced High‐Temperature Gas‐Cooled Reactor Fuel, Part II
Authors: Aihara Jun , Ueta Shohei , Yasuda Atsushi , Ishibashi Hideharu , Mozumi Yasuhiro , Sawa Kazuhiro , Motohashi Yoshinobu
Published: January 2009

The Japan Atomic Energy Agency (JAEA) has started to study and develop zirconium carbide (ZrC)‐coated fuel particles for advanced high‐temperature gas‐cooled reactors. The ZrC coating layer has been fabricated at JAEA by chemical vapor deposition using a pyrolytic reaction of zirconium bromide. The microstructures of the ZrC layers, whose nominal deposition temperatures could be measured and controlled during the deposition process, were characterized by means of TEM and STEM. In the present study, three batches were prepared and compared with each other as well as the previous batches. The crystallographic orientation of ZrC with regard to the growth direction in the ZrC layers deposited at a constant temperature of 1630 K was different from that deposited at varying temperatures in the 1493–1823 K range. A thin layer of turbostratic carbon was observed at the boundary between pyrolytic carbon and ZrC in particles deposited at the highest temperature among those used in this study (the nominal temperature was 1769 K); no such structure was found in a batch deposited at a lower temperature (the nominal temperature was 1632 K). Therefore, precise control of temperature is shown to be critical to the formation of good ZrC coatings.
Thermal Shock Resistance and Fracture Behavior of ZrB2–Based Fibrous Monolith Ceramics
Authors: Zimmermann James W. , Hilmas Gregory E. , Fahrenholtz William G.
Published: January 2009

The thermal shock resistance and fracture behavior of zirconium diboride (ZrB2)‐based fibrous monoliths (FM) were studied. FMs containing cells of ZrB2–30 vol% SiC with cell boundaries composed of graphite–15 vol% ZrB2 were hot pressed at 1900°C. The average flexure strength of the FMs was 375 MPa, less than half of the strength of hot‐pressed ZrB2–30 vol% SiC. Flexure specimens failed noncatastrophically and retained 50%–85% of their original strength after the first fracture event. A critical thermal shock temperature (ΔTc) of 1400°C was measured by water quench thermal shock testing, a 250% improvement over the previously reported ΔTc values for ZrB2 and ZrB2–30 vol% SiC of similar dimensions (4 mm × 3 mm × 45 mm). The flexure strength was maintained with ΔTc values of 1350°C and below. As ΔTc increased, the stiffness of the flexure specimen decreased linearly. The lower stiffness and improvement in thermal shock resistance is attributed to crack propagation in the cell boundary and crack deflection around the load‐bearing cells. The critical thermal shock was attributed to the fracture of the ZrB2–30% SiC cell material.
Fictive Temperature and the Glassy State
Authors: Mauro John C. , Loucks Roger J. , Gupta Prabhat K.
Published: January 2009

Within the glass science community, it is common to describe the state of a glass in terms of a fictive temperature or a distribution of fictive temperatures. However, a number of different definitions of fictive temperature are being practiced in the field. Based on the previous literature, at least three definitions are possible: (a) microscopic, which entails a mapping of the nonequilibrium glassy structure to comparable equilibrium liquid structures; (b) macroscopic, by representing the property values of a glass in terms of equilibrium states with equivalent configurational property values; and (c) kinetic, where the fictive temperatures are used to represent the various relaxation modes within the glass. Of these, the first, microscopic definition offers the possibility of writing a simplified statistical mechanical model of the nonequilibrium glassy state in terms of a linear combination of equilibrium liquid states. However, in this paper, we show that the microscopic physics of a glass cannot, in general, be described in this manner. The fictive temperature description of the glassy state is rigorous only under special circumstances, such as the case of an infinitely fast quench through the glass transition regime. Nevertheless, the microscopic definition of fictive temperature can provide a reasonable description of ensemble‐averaged state properties such as enthalpy and molar volume, where there is a cancellation of errors. The concept of fictive temperature distribution cannot, however, capture accurately the fluctuations in enthalpy and molar volume in the glassy state. We also show that fictive temperature mapping does not provide an accurate description of the low‐temperature dynamics of glass. An alternative description of the glassy state in terms of an enthalpy landscape can account for the true statistical mechanics of the glassy state without relying on any notion of fictive temperature.
Effects of Reducing Atmosphere on the Luminescence of Eu3+‐Doped Yttria‐Stabilized Zirconia Sensor Layers in Thermal Barrier Coatings
Authors: Shen Yang , Clarke David R.
Published: January 2009

The use of Eu3+‐doped yttrium‐stabilized zirconia (YSZ) as an embedded layer in thermal barrier coatings for luminescence temperature sensing has previously been demonstrated in air. In this work the effects of exposure to reducing atmospheres on the luminescence spectra and luminescence lifetime as a function of temperature are reported. No effect of reducing atmosphere, down to oxygen partial pressures(

) of <10−11 ppm, on either the Eu3+ luminescence spectrum or the luminescence lifetime up to 900°C are seen although the overall luminescence intensity is decreased. The insensitivity of the temperature dependence of the luminescence lifetime to oxygen partial pressure indicates that Eu3+‐doped YSZ based temperature sensors can be used with confidence in reducing as well as in air atmospheres. The results also suggest that the charge transfer mechanism responsible for the temperature dependence of the luminescence lifetime is unaffected by the oxygen vacancies introduced by reduction.
Do you hear them working? Listening to, experimenting with and architecting work process
Authors: GLUESING JULIA C.
Published: January 2009

This EPIC2007 session draws our attention to ethnographic approaches for understanding work process in context. Each paper highlights ethnography's uses to promote new ways of working through experimentation and innovative design or architecture of work and work processes. The purpose of this introduction is to provoke discussion from multiple angles of the ethnographic approaches to work process described in these papers as well as to focus attention on the work processes in which ethnographers themselves are embedded.
Teaching organizational ethnography
Authors: IKEYA NOZOMI , VINKHUYZEN ERIK , WHALEN JACK , YAMAUCHI YUTAKA
Published: January 2009

In 2004 Fujitsu asked PARC to carry out an ethnographic investigation of their software business, focusing on their development processes, and while doing so to build an ethnographic capability in their own organization. One of our biggest challenges was to convince Fujitsu's system engineers — and the development organization more generally — of the value of ethnography for their business. They are used to translating what they hear from customers about the workflow into a standard framework of system requirements and specifications; it was difficult for them to see the relevance of putting any significant focus on understanding what is going on in the workplace at the level of everyday work practices. Moreover, in their work with customers, system engineers commonly proceed in a carefully planned and highly structured manner, where every activity is expected to yield predictable outcomes. For them, the open‐ended nature of ethnographic fieldwork seemed dangerously chaotic and unpredictable. The lessons learned from our experience with both our initial teaching of the engineers and the organizational fieldwork we later did together helped us design a new ethnography‐training course that incorporates the task of conveying the full value of organizational and business ethnography.
Role of serum cytokines tumour necrosis factor‐α and interleukin‐6 in the association between body weight and periodontal infection
Authors: Saxlin Tuomas , Suominen‐Taipale Liisa , Leiviskä Jaana , Jula Antti , Knuuttila Matti , Ylöstalo Pekka
Published: January 2009

Aim: To study the role of serum cytokines tumour necrosis factor α (TNF‐α) and interleukin 6 (IL‐6) as potential mediators in the association between body weight and periodontal infection among an adult population.

Material and Methods: This study was based on a subpopulation of the Health 2000 Health Examination Survey, which included dentate non‐diabetic, non‐rheumatic subjects, aged between 45 and 64 years, who had never smoked and whose serum levels of TNF‐α and IL‐6 were analysed and whose periodontal status was clinically determined (effective n=425). The number of teeth with periodontal pockets of 4 mm or more and the number of teeth with periodontal pockets of 6 mm or more were used as outcome variables. Relative risks and 95% confidence intervals were estimated using Poisson regression models.

Results: Serum IL‐6, but not TNF‐α associated with teeth with deepened periodontal pockets. Multivariate models showed that IL‐6, but not TNF‐α, could mediate the effect of body weight on periodontium.

Conclusion: In this population of non‐diabetic and non‐rheumatic subjects, who had never smoked, serum IL‐6 was associated with periodontal infection. The results suggest that serum IL‐6 could be one mediating factor that connects body weight and periodontal infection.
Air oxidation increases skin irritation from fragrance terpenes
Authors: Christensson Johanna Bråred , Forsström Pia , Wennberg Ann‐Marie , Karlberg Ann‐Therese , Matura Mihály
Published: January 2009

Background:  Linalool and limonene are common fragrance terpenes that autoxidize on air exposure. The pure compounds are not allergenic but their oxidation products can cause contact allergy. Little has been investigated regarding the irritancy of oxidized terpenes.

Aim:  The aim of this study was to investigate the irritating effect of pure and oxidized R‐limonene and linalool in concentration series and to study the MNIC (Maximum Non Irritant Concentration) of autoxidized linalool and limonene.

Patients/methods:  Patch testing was performed in dermatitis patients and controls with sequentially diluted concentrations of oxidized and non‐oxidized linalool, and oxidized and non‐oxidized R‐limonene. Readings were made with visual assessment and using laser Doppler imaging.

Results:  The non‐oxidized terpenes were non‐irritating in all tested concentrations. Both linalool and especially R‐limonene were more irritating after oxidation compared with the pure compounds. No difference in response was seen between dermatitis patients and controls.

Conclusion:  Autoxidation of the fragrance terpenes linalool and R‐limonene increases irritation. Oxidized linalool is less irritating than oxidized R‐limonene. In this study, we found no advantages in using laser Doppler technique compared with visual assessment.
Karyotype complements the International Prognostic Scoring System for primary myelofibrosis
Authors: Hussein Kebede , Huang Jocelin , Lasho Terra , Pardanani Animesh , Mesa Ruben A. , Williamson Cynthia M. , Ketterling Rhett P. , Hanson Curtis A. , Van Dyke Daniel L. , Tefferi Ayalew
Published: January 2009

Objectives:  The International Prognostic Scoring System (IPSS) for primary myelofibrosis (PMF) is based on five independent predictors of inferior survival: age >65 yr, hemoglobin <10 g/dL, leukocyte count >25 × 109/L, circulating blasts ≥1%, and presence of constitutional symptoms. The presence of 0, 1, 2, and ≥3 adverse factors defines low, intermediate‐1, intermediate‐2, and high risk disease, respectively. We examined the additional prognostic relevance of karyotype.

Methods:  World Health Organization criteria were used for PMF diagnosis. Only patients with bone marrow cytogenetic studies at the time or within 1 yr of diagnosis and a minimum of 20 evaluable metaphases were considered. Cytogenetic findings were categorized as ‘normal’ vs. ‘abnormal’ or ‘favorable’ (normal or with sole abnormalities of 13q− or 20q−) vs. ‘unfavorable’ (all other abnormalities).

Results:  A total of 109 patients were studied (median age 63 yr). Numbers of patients in the above‐listed four IPSS risk groups were 26, 31, 28, and 24, respectively. Cytogenetic results were abnormal in 33% of the patients and unfavorable in 21%. At a median follow‐up of 35 months, 45 (41%) deaths were recorded. ‘Unfavorable’ (P = 0.008) but not ‘abnormal’ (P = 0.19) karyotype predicted shortened survival and its significance remained on multivariable analysis that included the IPSS or other prognostic tools as covariates. JAK2V617F, detected in 63 (58%) patients, was inconsequential to survival.

Conclusions:  In PMF, specific cytogenetic abnormalities and not the mere presence of an abnormal karyotype provide important prognostic information that is not accounted for by the IPSS or other established risk factors.
Evaluation of Adjuvant Doxorubicin‐Based Chemotherapy for the Treatment of Feline Mammary Carcinoma
Authors: McNeill C.J. , Sorenmo K.U. , Shofer F.S. , Gibeon L. , Durham A.C. , Barber L.G. , Baez J.L. , Overley B.
Published: January 2009

Background:Feline mammary carcinomas (FMC) are locally invasive and highly metastatic tumors. Because of the high metastatic potential, patients often are treated with adjuvant doxorubicin‐based chemotherapy, but little data exist to evaluate the effect of this strategy.

Hypothesis:Adjuvant doxorubicin‐based chemotherapy improves outcome for FMC compared with surgery alone.

Animals:Cats with naturally occurring, biopsy‐confirmed FMC treated with either surgery alone (Sx) or with surgery plus adjuvant doxorubicin‐based chemotherapy (Sx + Chemo).

Methods:Retrospective cohort study. Clinical data were collected and compared to identify differences between groups. Outcome results were determined and compared. Prognostic factors for disease‐free survival (DFS) and overall survival were evaluated.

Results:Seventy‐three cats were evaluated, of which 37 were in the Sx group and 36 in the Sx + Chemo group. No differences in clinical data were found between Sx and Sx + Chemo groups. Median DFS times for the Sx and Sx + Chemo groups were 372 and 676 days, respectively (P= .15) and median survival times (ST) were 1,406 and 848 days, respectively (P= .78). For cats that underwent a unilateral radical mastectomy, ST was significantly longer for the Sx + Chemo compared with the Sx group (1,998 versus 414 days, respectively;P= .03).

Conclusions and Clinical Importance:This study did not find a benefit to adjuvant doxorubicin‐based chemotherapy in cats with FMC. Additional studies are required to determine whether patient subgroups with negative prognostic factors may benefit from adjuvant chemotherapy.
Ca2+‐dependent induction of TRPM2 currents in hippocampal neurons
Authors: Olah Michelle E. , Jackson Michael F. , Li Hongbin , Perez Yaël , Sun Hong‐Shuo , Kiyonaka Shigeki , Mori Yasuo , Tymianski Michael , MacDonald John F.
Published: January 2009

TRPM2 is a Ca2+‐permeable member of the transient receptor potential melastatin family of cation channels whose activation by reactive oxygen/nitrogen species (ROS/RNS) and ADP‐ribose (ADPR) is linked to cell death. While these channels are broadly expressed in the CNS, the presence of TRPM2 in neurons remains controversial and more specifically, whether they are expressed in neurons of the hippocampus is an open question. With this in mind, we examined whether functional TRPM2 channels are expressed in this neuronal population. Using a combination of molecular and biochemical approaches, we demonstrated the expression of TRPM2 transcripts and proteins in hippocampal pyramidal neurons. Whole‐cell voltage‐clamp recordings were subsequently carried out to assess the presence of TRPM2‐mediated currents. Application of hydrogen peroxide or peroxynitrite to cultured hippocampal pyramidal neurons activated an inward current that was abolished upon removal of extracellular Ca2+, a hallmark of TRPM2 activation. When ADPR (300 μm) was included in the patch pipette, a large inward current developed but only when depolarizing voltage ramps were continuously (1/10 s) applied to the membrane. This current exhibited a linear current–voltage relationship and was sensitive to block by TRPM2 antagonists (i.e. clotrimazole, flufenamic acid and N‐(p‐amylcinnamoyl)anthranilic acid (ACA)). The inductive effect of voltage ramps on the ADPR‐dependent current required voltage‐dependent Ca2+ channels (VDCCs) and a rise in [Ca2+]i. Consistent with the need for a rise in [Ca2+]i, activation of NMDA receptors (NMDARs), which are highly permeable to Ca2+, was also permissive for current development. Importantly, given the prominent vulnerability of CA1 neurons to free‐radical‐induced cell death, we confirmed that, with ADPR in the pipette, a brief application of NMDA could evoke a large inward current in CA1 pyramidal neurons from hippocampal slices that was abolished by the removal of extracellular Ca2+, consistent with TRPM2 activation. Such a current was absent in interneurons of CA1 stratum radiatum. Finally, infection of cultured hippocampal neurons with a TRPM2‐specific short hairpin RNA (shRNATRPM2) significantly reduced both the expression of TRPM2 and the amplitude of the ADPR‐dependent current. Taken together, these results indicate that hippocampal pyramidal neurons possess functional TRPM2 channels whose activation by ADPR is functionally coupled to VDCCs and NMDARs through a rise in [Ca2+]i
An Experimental Study of the Gaseous Pollution Emissions in Petroleum-Coke-Fired Fluidized Beds
Authors: Zhang Chun-Lin , Yuan Gui-Cheng , Liu De-Chang , Chen Han-Ping , Liu Ding-Yu , Wang Rong
Published: January 2009

Petroleum cokes have high calorific value (about 37 MJkg−1), high sulfur content (2–7% wt.), and high nitrogen content (1∼3% wt.), introducing serious environmental problems when using as fuel. In this paper the effects of operating parameters (bed temperature, Ca/S mole ratio, and excess oxygen) on gaseous pollutant (SO2, NO, and N2O) emissions in a well-controlled bench scale fluidized bed reactor and an 1t/h bubbling fluidized bed for different type of petroleum cokes. Finally, the pollution emission differences between petroleum coke and coal were compared and the reasons were analyzed.
Behavior of Organic and Inorganic Micropollutants in Chlorine Spiked Sludge Incineration by a Circulating Fluidized Bed Furnace
Authors: Mininni Giuseppe , Marani Dario , Braguglia Camilla Maria , Guerriero Ettore , Sbrilli Andrea
Published: January 2009

The effects of combustion and feeding conditions on Polycyclic Aromatic Hydrocarbons (PAH) and PCDD/F formation and appearance in the emissions at the stack during sludge incineration are discussed in this paper. Partitioning in the solid streams of Cd, Cr, Cu, Mn, Ni, Pb and Zn is also analyzed. Tests were performed on a demonstrative plant equipped with a fluidized bed furnace (FBF) using sewage sludge either as is or spiked with chlorinated organic compounds (tetrachloroethylene or a mixture of tetrachloroethylene, chlorobenzene and toluene) to study the chlorine effect on the presence of micropollutants in the different streams. Exhaust gases were sampled both before and after the treatment system (bag house and wet scrubber). In the untreated flue gas the highest values of PCDD/F and PAH were detected when the afterburning chamber was not in use or operating at low temperatures. Operation of the afterburning chamber at temperature higher than 850–900 °C was sufficient to keep organic micropollutants concentrations in the untreated flue gas at reasonably low levels. No significant correlation of the operating conditions with emissions at the stack was found. High copper concentration in the feed enhanced PCDD/F formation, with exception of tests carried out with high afterburning temperature. The homologue profile of PCDD/F and PAH depended on test conditions. Preferential accumulation of heavy metals in the filter ash with respect to cyclone ash was quantified in terms of an enrichment factor. Out of the seven metals considered, only Cd and Pb undergo significant enrichment in the filter ash. The enrichment increased with increasing chlorine content of the feed. In contrast, Cu, Cr, Mn, Ni, and Zn behaved as refractory (non-volatile) elements even at high chlorine dosage. In accordance with the widely accepted hypothesis that metal enrichment is due to metal vaporization in the combustion chamber and subsequent condensation onto the filter ash particles, a thermodynamic model of the combustion process was able to satisfactorily predict the different metal behavior and the effect of chlorine dosage on metal enrichment.
The Effect of Coal Type on Thermal Balance in a Dense Phase of a Circulating Fluidized Bed Combustor
Authors: Komatina Mirko S. , Liu Xin , Winter Franz
Published: January 2009

The results of experimental investigations of the effect of coal type on the thermal balance during early stages in a dense phase of a circulating fluidized bed combustor (CFBC) are presented in this paper. The experimental investigations were performed in a laboratory-scale CFBC. Five coals with three size classes (small 0.5–0.63 mm, medium 2–3.1 mm, and large 7.1–8 mm) were tested. The electrical heating system was used to ensure that the riser has a constant temperature (850°C) before the experiments. Mean velocity was 1.2 m/s. Oxygen concentration was 5%. During the experiments the temperature in the dense phase in the lower part of the riser and the gas concentrations of CO and CO2 were measured continuously. On the temperature histories measured, it can be seen that after feeding the coal batch into the hot CFBC, the temperature in the dense phase decreases, after reaching a minimum value and increases back again. The experimental results were compared to each other on the basis of the maximum temperature drop after feeding the coal batch. It was concluded that the temperature drop depends slightly on coal size and mainly on coal type and its mechanical and physical structure. The temperature drop slightly increases when the particle size of the coal batch increases. The strongest influence on the temperature drop in the dense phase of the CFBC shows the volatile content of the original coal and the temperature drop is directly proportional to the volatile content.
Attrition Behavior of Coal Ash Under Circulating Fluidized Bed Combustion Conditions
Authors: Winter Franz , Liu Xin
Published: January 2009

The attrition behavior of ash produced from two bituminous and one anthracite coal was studied under laboratory-scale circulating fluidized bed combustor (CFBC) conditions. After the ash was produced in the oven, the ash sample with a size range from 0.1 to 1 mm was fed into the hot CFBC, which was heated by electrical heating shells and fluidized by air. The laboratory-scale CFBC was operated with using fine silica sand (40 to 80 μm) as bed material. After a certain time the operation was stopped, all particles were collected and sieving analysis was performed to obtain the actual particle size distribution (PSD) of the coal ash. The operating conditions were changed in a wide range, i.e. the bed temperature from 600 to 850°C, the fluidizing velocity from 1.2 to 2 m/s, the residence time from 60 to 120 min and the design of the cyclone. The effects of operating conditions and coal type were studied and their relative importance is discussed. Elemental analysis of the coal ashes showed that Si and Ca may play an important role during attrition.
Biomass Ash – Bed Material Interactions Leading to Agglomeration in FBC
Authors: Visser H. J. M. , van Lith S. C. , Kiel J. H. A.
Published: January 2009

In (bubbling) fluidized-bed combustion and gasification of biomass, several potential problems are associated with the inorganic components of the fuel. A major problem area is de-fluidization due to bed agglomeration. The most common found process leading to de-fluidization in commercial-scale installations is “coating-induced” agglomeration. During reactor operation, a coating is formed on the surface of bed material grains and at certain critical conditions (e.g., coating thickness or temperature) sintering of the coatings initiates the agglomeration. In an experimental approach, this work describes a fundamental study on the mechanisms of de-fluidization. For the studied process of bed de-fluidization due to sintering of grain-coating layers, it was found that the onset of the process depends on: a) a critical coating thickness, b) on the fluidization velocity when it is below approx. four times the minimum fluidization velocity and c) on the viscosity (stickiness) of the outside of the grains (coating).
A Simulation Study for Fluidized Bed Combustion of Petroleum Coke With CO2 Capture
Authors: Wang Jinsheng , Anthony Edward J. , Abanades J. Carlos
Published: January 2009

Petroleum coke is regarded as a difficult fuel because of its high sulphur content and low volatile content. However, its low price and increased production, means that there is a powerful economic stimulus to use it for power generation. In this work, a process simulation has been performed as part of a feasibility study on the utilization of petroleum coke for power generation with low-cost CO2 capture. The proposed system employs a pressurized fluidized bed combustor and a calciner. In the combustor itself, the petroleum coke is burned and most of the CO2 generated is captured by a CaO sorbent under pressurized condition to form CaCO3. The CaCO3 is transported into the calciner where limited proportion of the petroleum coke is burned with pure O2, and calcines the spent sorbent back into CaO and CO2. A nearly pure CO2 stream is obtained from the calciner for subsequent disposal or utilization. The predicted overall efficiency of the combustion is near 40%. The proposed system would also be suitable for firing other high carbon and low ash fuel, such as anthracite.
Providing and Processing Fuel
Authors: Dicks Andrew L.
Published: January 2009

Hydrogen, the preferred fuel for fuel cells, can be obtained from many sources. Fossil fuels such as oil, natural gases and coal, as well as bio-fuels can all be chemically converted to hydrogen. The basic chemistry of the various steps in the conversion is well known. However, each type of fuel cell has different fuelling requirements and therefore the design of fuel processors depends not only on the availability and form of fuel but also the application. For stationary power plants natural gas is an ideal fuel. It is best converted to hydrogen as close to the fuel cell as possible. In the case of the MCFC and SOFC this ensures high efficiency by using heat that would otherwise be lost from the stack. Recent advances in micro-channel catalytic reactor design may also lead to higher efficiencies and more compact stationary and portable systems. For transportation applications, hydrogen appears to be the preferred fuel in the long term. In the near term, methanol is a good fuel to use in vehicles, since it can be converted relatively easily on-board to hydrogen. Hydrogen can be generated by electrolysing water, and in combination with a fuel cell, this offers a means of storing energy from intermittent renewable power sources. In the future, hydrogen may be generated by direct solar electro-photolysis, or by biological methods. As such technologies advance, the transportation and storage of hydrogen stands out as perhaps the major barrier to the realisation of commercial fuel cell systems.
Development of a Comprehensive Simulation Platform to Investigate System Interactions Among Solid-Oxide Fuel Cell, Power-Conditioning Systems, and Application Loads
Authors: Mazumder S. K. , Burra R. , Acharya K. , von Spakovsky M. R. , Nelson D. , Rancruel D. , Haynes C. , Williams R.
Published: January 2009

SOFC stacks respond quickly to changes in load and exhibit high part- and full-load efficiencies (due to rapid electrochemistry), which is not true for the balance of plant (BOP), where load-following time constants are several orders of magnitude higher. This dichotomy diminishes the reliability and performance of the electrode with increasing demand of load. Because these unwanted phenomena are not well understood, the manufacturers of SOFC use conservative schemes to control stack responses to load variations, which limit the applicability of SOFC systems from a cost standpoint. Thus, a need exists for the synthesis of component- and system-level models of SOFC power-conditioning systems and the development of methodologies for investigating the system-interaction issues (which reduce the lifetime and efficiency of a SOFC) and optimizing the responses of each subsystem. Equally important are “multiresolution” finite-element modeling and simulation studies that can predict the impact of changes in system-level variables (e.g., current ripple and load-transients) on the local current densities, voltages, and temperature (these parameters are very difficult or cumbersome, if not impossible to obtain) within a SOFC cell. Towards that end, this paper presents a design methodology (with illustrations) for a simulation tool that will enable comprehensive analyses of above (critical) issues.
State of the Art About the Effects of Impurities on MCFCs and Pointing Out of Additional Research for Alternative Fuel Utilization
Authors: Desideri U. , Lunghi P. , Burzacca R.
Published: January 2009

Fuel cells are very flexible energy conversion devices and in particular MCFC power generating system are among the most promising for stationary power generation. Potentially, MCFCs can be fed by a great variety of gaseous fuels comprising low calorific values gases like landfill gas. Thanks to fuel processing technologies, like gasification, suitable anode input gases can also be obtained from solid matters. Coal, but also RDF (Refuse Derived Fuel), industrial waste and biomasses are potential fuels for the fuel cell technology after a specific treatment aimed to yield a proper gas for the cell requirements. The gases mentioned above are characterized by low calorific values, presence of inert gases, presence of carbon monoxide and dioxide, presence of various contaminants such as chlorine, sulphur and nitrogen compounds or metals and they can be utilized for power production in high temperature fuel cell units only after a proper clean-up treatment (tars, particulate and sulphur removal). Although interest in alternative fuels for fuel cells has spread in the recent years, most research activity related to fuel treatment has been performed on methane. The biggest drawback deriving from this situation is a general lack of information. When present, moreover, the information is often contradictory. An example of this is given by the acceptable contaminants levels for molten carbonate fuel cells about which there are not values that are based on sufficient experimental evidence. Unfortunately the design of a clean-up system, the choice of the best technology, the optimization of the BOP relies just on these values. In this work a literature research and an analysis of the present knowledge about the effect of impurities in fuel for fuel cells has been preformed. The goal is the definition of concentration levels that can be tolerated by MCFCs and the degradation in performance or the reduction of cell life related to the presence of different pollutants. A second step of the work is the comparison of the levels of impurities tolerated by the cells with those present in the different low calorific value gases in order to define the clean-up requirements. The research priorities in this field have been pointed out. Finally, the project of the fuel cell team of University of Perugia about this topic is briefly described.
Gasification and Fuel Cell Integration With Bottoming Turbine Cycle: Performances of a Hybrid Plant for Electricity Production
Authors: Lunghi P. , Burzacca R.
Published: January 2009

The increasing need of energy resources along with the growing environmental interest promote the creation of new concepts in the field of energy production and management strategies. The development of high temperature fuel cells, suitable for stationary energy production, is one of the most promising aspects, able to bring a significant change in the power generation scenario. One of the most important features for fuel cells is the potential coupling with advanced gasification systems, thus enabling the possibility of energy recovery from waste, RDF (Refuse Derived Fuel) and biomass. The gasification process transfers the energetic value of the original solid fuel to a gaseous product rich in hydrogen, carbon monoxide and dioxide, and other compounds. A post-gasification treatment removes tars, particulates, impurities and makes the gas suitable for power production in a fuel cell unit. In this work an example of an innovative plant for biomass utilization has been considered. The plant includes a gasification section and a Molten Carbonate Fuel Cell unit, coupled with a hot gas cleanup system. For gasification technology, a recent typology was considered involving an indirect heating system such as the Battelle process. Gaseous streams conveyed to the cell after the conditioning processes were considered. In order to achieve higher efficiencies, a bottoming cycle has been added. It comprises a turbine power plant integrated with the gasification and fuel cell lay-out. In the turbine cycle air is compressed in the operating pressure and internally heated by the waste heat of the fuel cell and of the gasification process. The expanded air is then used in the combustion reactor of the gasification system. The proposed plant allows high electric efficiency and high flexibility in choosing for air compression ratio and unit size; sensitivity analyses were performed.
An Evaluation of Cooling Systems for PEMFCs in Transport Applications
Authors: Oseen-Senda K. M. , Pauchet J. , Feidt M. , Lottin O.
Published: January 2009

Polymer Electrolyte Fuel Cells in transportation applications require specific cooling systems. Inside the cell itself, the temperature must remain relatively constant to avoid problems of condensation or dry out that would adversely affect its efficiency. The cooling system must also deal with several challenges unique to fuel cells: it must not conduct electricity across the cells, and it must withstand freezing and cold start-up. Moreover, the cooling system must be compact and light to keep the energy density of the stack as high as possible. Unlike the conventional internal combustion engine in today’s cars, the fuel cell engine works at a low temperature. This means that the entire automobile cooling system must be redesigned to dissipate this low quality heat. To better compare various cooling systems, we have done a patent search of current system designs.
Performance of New Hybrid Solar Lighting Luminaire Design
Authors: Earl Dennis D. , Maxey L. Curt , Muhs Jeff D. , Thomas Robert R.
Published: January 2009

We report on the performance of a new hybrid luminaire designed to blend light from a fiber optic solar source with electric fluorescent lamps. The luminaire design studied involves a commercially-available fluorescent luminaire that had been modified to include optical elements for efficiently dispersing a fiber optic solar light source. Quantitative measurements of the hybrid luminaire’s optical efficiency and spatial intensity distribution/deviations are discussed. The effects of static differences and dynamic fluctuations in spatial intensity distribution are qualitatively discussed and potential design improvements examined.
Continuous Tracking of Heliostats
Authors: Kribus A. , Vishnevetsky I. , Meri M. , Yogev A. , Sytnik A.
Published: January 2009

Tracking motions in current heliostats are usually performed in discrete steps, even though the motion of the sun is continuous. Aiming errors due to the discrete steps are often about 1 mrad or more. A significant reduction of tracking error by smooth continuous tracking is presented. The implementation uses an electronic speed control unit to modify the rotational speed of the two AC motors on an existing heliostat. The continuous tracking system was implemented and successfully operated at the Weizmann Institute heliostat field. Measurements of heliostat motion show that aiming error due to tracking intervals was practically eliminated. A comparison of heliostat motions and flux on the target in step-tracking and continuous tracking modes is reported.
Advanced Thermal Energy Storage Technology for Parabolic Trough
Authors: Tamme Rainer , Laing Doerte , Steinmann Wolf-Dieter
Published: January 2009

The availability of storage capacity plays an important role for the economic success of solar thermal power plants. For today’s parabolic trough power plants, sensible heat storage systems with operation temperatures between 300°C and 390°C can be used. A solid media sensible heat storage system is developed and will be tested in a parabolic trough test loop at PSA, Spain. A simulation tool for the analysis of the transient performance of solid media sensible heat storage systems has been implemented. The computed results show the influence of various parameters describing the storage system. While the effects of the storage material properties are limited, the selected geometry of the storage system is important. The evaluation of a storage system demands the analysis of the complete power plant and not only of the storage unit. Then the capacity of the system is defined by the electric work produced by the power plant, during a discharge process of the storage unit. The choice of the operation strategy for the storage system proves to be essential for the economic optimization.
Hydrogen Production by Solar Thermochemical Water-Splitting/Methane-Reforming Process
Authors: Kodama Tatsuya , Kondoh Yoshiyasu , Kiyama Atsushi , Shimizu Ken-Ich
Published: January 2009

Two different routes of solar thermochemical hydrogen production are reviewed. One is two-step water splitting cycle by using a metal-oxide redox pair. The first step is based on the thermal reduction of metal oxide, which is a highly endothermic process driven by concentrated solar thermal energy. The second step involves water decomposition with the thermally-reduced metal oxide. The first thermal reduction process requires very-high temperatures, which may be realized in sun-belt regions. Another hydrogen production route is solar reforming of natural gas (methane), which can convert methane to hydrogen via calorie-upgrading by using concentrated solar thermal energy. Solar reforming is currently the most advanced solar thermochemical process in sun belt. There is also possibility for the solar reforming to be applied for worldwide solar concentrating facilities where direct insolation is weaker than that in sun belt. Our experimental studies to improve the relevant catalytic technologies are shown and discussed.
Design of Commercial Solar Tower Systems: Utilization of Solar Induced Convective Flows for Power Generation
Authors: Schlaich Jo¨rg , Bergermann Rudolf , Schiel Wolfgang , Weinrebe Gerhard
Published: January 2009

An updraft Solar Tower power plant — sometimes also called ‘solar chimney’ — is a solar thermal power plant utilizing a combination of solar air collector and central updraft tube to generate a solar induced convective flow which drives pressure staged turbines to generate electricity. In the paper we first describe the functional principle of the Solar Tower and give some results from designing, building and operating a small scale prototype in Spain. Then future commercial Solar Tower systems like the one being planned for Australia are described. We present technical issues and basic economic data.
An Economic Analysis Method of Energy Saving Strategies in Newly Constructed Buildings
Authors: Sylvester K. Everette , Haberl Jeff
Published: January 2009

Businesses and institutions in the United States spend an estimated $175 billion per year for energy. Of that, the fraction under performance contracts and energy service agreements is currently growing, aided by cheaper monitoring technology and integration with energy management and conservation systems. To estimate the potential savings as well as to help verify energy savings retrofits, the American Society of Heating, Refrigeration and Air Conditioning Engineers has developed Standard 90.1 to provide guidance when conducting energy simulations of buildings before they are constructed. Although the potential accuracy afforded by today’s energy simulation programs is high, there is little agreement on current methods when developing the base case building. In addition, there are no current standards to guide the analysis of newly constructed, energy efficient buildings. This paper presents an energy simulation of a newly constructed state office building and compares the energy savings a past study the uses ASHRAE Standard 90.1 and a simulation regression method. Overall, while the results show significant differences between the ASHRAE Standard 90.1 and the calibrated simulation regression method.