bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Oxygen Vacancies on the Hot Hardness of Mullite
Authors: Pitchford James E. , Stearn Robert J. , Kelly Anthony , Clegg William J.
Published: January 2009

The structure of mullite, which has a composition ranging from 3Al2O3·2SiO2 to Al2O3·2SiO2, contains ordered oxygen vacancies. Sillimanite, Al2O3·SiO2, has a similar structure but with no vacancies. The indentation hardness of polycrystalline mullite (3Al2O3·2SiO2) was measured from room temperature up to 1400°C and compared with that of single‐crystal sillimanite (Al2O3·SiO2) up to 1300°C. It was found that both materials show the same variation in hardness with temperature, suggesting that the structures have a similar resistance to plastic deformation, and therefore that the oxygen vacancies in the mullite structure are not the primary cause of mullite's resistance to high‐temperature deformation.
Double Injection Synthesis and Dispersion of Submicrometer Barium Titanyl Oxalate Tetrahydrate
Authors: Kimel R. Allen , Ganine Vladimir , Adair James H.
Published: January 2009

A modified Clabaugh method has been used to produce a well‐dispersed barium titanyl oxalate tetrahydrate (BTO) powder with a particle size of less than 0.2 μm. Production of the BTO powder is based on a double injection system, with reactants rapidly mixed using pressurized gas. The mixture resulting from the double injection of the reactants was subsequently quenched into a solution containing polyethyleneimine as a dispersant. The resulting dispersed BTO powder forms a suspension that is stable against coarsening or aggregation for greater than 1400 h. The dispersed BTO powder was also shown to produce BaTiO3 with a particle size of 0.25 μm or less after calcination.
Nonisothermal Synthesis of Yttria‐Stabilized Zirconia Nanopowder through Oxalate Processing: II, Morphology Manipulation
Authors: Vasylkiv Oleg , Sakka Yoshio , Borodians'ka Hanna
Published: January 2009

A novel, nontraditional route for controlling the morphology of yttria‐stabilized zirconia nanopowders is explained. For understanding the real nature of yttrium zirconium oxalate nonisothermal decomposition and for the development of nanosize 3 mol% Y2O3·97mol% ZrO2, mass spectrometry, X‐ray, and TEM investigation were used. Characteristics of zirconia crystallization under nonisothermal heating conditions were studied. Morphology evolution during Y‐Zr oxalate nonisothermal decomposition was investigated to optimize the heating schedule of calcination. The nonlinear heating regime has been used to produce nanosized Y2O3‐stabilized tetragonal ZrO2 powder with the finest primary crystallites and narrowest secondary aggregate size distribution.
Competitive Adsorption Phenomena in Nonaqueous Tape Casting Suspensions
Authors: Blackman Kim , Slilaty Rita M. , Lewis Jennifer A.
Published: January 2009

Competitive adsorption phenomena in alumina (α‐Al2O3)–polyvinyl butyral (PVB)–Menhaden fish oil (MFO) suspensions are studied using diffuse reflectance Fourier transform infrared spectroscopy and thermogravimetric analysis. PVB and MFO commonly serve as binder and dispersant species, respectively, in nonaqueous tape casting systems. Adsorption isotherm measurements reveal that both PVB and MFO have an affinity for α‐Al2O3 surfaces, with corresponding plateau coverages of 3.4 and 2.3 mg/m2, respectively. Sequential competitive adsorption of these species occurred during two‐stage milling. MFO was fully adsorbed onto α‐Al2O3 powder in the absence of PVB during first‐stage milling. PVB was then introduced to the system during second‐stage milling and found to displace preadsorbed MFO species from such surfaces. At the culmination of milling, PVB composed 25–35 wt% of the adsorbed organic layer. Complete displacement of MFO was not observed, which limited PVB adsorption on α‐Al2O3.
Processing, Characterization, and Dielectric Studies on K(Ta1−xNbx)O3 for Use at Cryogenic Temperatures
Authors: DiAntonio Cristopher B. , Pilgrim Stephen M.
Published: January 2009

Development of the next generation space telescope, to supplement the Hubble Space Telescope, has heightened the need for cryogenic actuators. High performance electromechanical materials are needed for use from 10 to 77 K. The use of piezoelectric materials to satisfy this need involves major property trade‐offs; consequently, alternative materials are of interest—the electrostrictive ceramics. The electrostrictors operate above their “Curie” (transition) temperature, and have electromechanical properties that can be superior to conventional piezoelectric materials. Because work on the electrostrictive materials is limited, the K(Ta,Nb)O3 solid solution system has been chosen as a viable material for use at cryogenic temperatures. These solid solutions have predicted transition temperatures in the range of 4 to 150 K. Two separate KTaO3 powders were synthesized with 10 and 17.5 mol% Nb2O5 doping levels. The powders were synthesized via a conventional mixed oxide route and materials were fabricated using a tape cast and laminating technique. Powders and samples were characterized using laser scattering, scanning electron microscopy, and surface area analysis to determine particle size distribution and morphology, powder X‐ray diffractometry for phase composition, and dielectric response as a function of frequency and temperature. Tape casting and lamination produced final samples that were fabricated to ∼88% of theoretical density. Dielectric measurements resulted in Curie temperatures of 248 and 123 K, and weak‐field permittivity values of ∼2700 and 4000 for 17.5 and 10 mol% additions of Nb2O5 to KTaO3.
High‐Temperature Rheology of Calcium Aluminosilicate (Anorthite) Glass‐Ceramics under Uniaxial and Triaxial Loading
Authors: Nair Balakrishnan G. , Cooper Reid F. , Bruhn David , Kohlstedt David L.
Published: January 2009

The high‐temperature creep behavior of two fine‐grained (∼3 μm) anorthite‐rich glass‐ceramics was characterized at ambient pressure and under a confining pressure of ∼300 MPa. Experiments were done at differential stresses of 15–200 MPa and temperatures of 1200°–1320°C. Of the two materials, one had a tabular (lathlike) grain structure with finely dispersed second phase of mullite, mostly in the form of ∼3–5 μm grains comparable to that of the primary anorthite phase, whereas the other had an equiaxed grain morphology with fine (∼400 nm) mullite precipitates concentrated at the anorthite grain boundaries. The results of creep experiments at ambient pressure showed that the material with the tabular grain structure had strain rates at least an order of magnitude faster than the equiaxed material. Creep in the tabular‐grained material at ambient pressure was accompanied by a significant extent of intergranular cavitation: pore‐volume analysis before and after creep in this material suggested that >75% of the bulk strain was due to growth of these voids. The equiaxed material, in contrast, showed a smooth transition from Newtonian (n= 1) creep at low stresses to non‐Newtonian behavior at high stresses (n > 2). Under the high confining pressure, the microstructures of both materials underwent significant changes. Grain‐boundary mullite precipitates in the undeformed, equiaxed‐grain material were replaced by fine (∼100 nm), intragranular precipitates of silliminate and corundum because of a pressure‐induced chemical reaction. This was accompanied by a significant reduction in grain size in both materials. The substantial microstructural changes at high confining pressure resulted in substantially lower viscosities for both materials. The absence of mullite precipitates at the grain boundaries changed the behavior of the equiaxed material to non‐Newtonian (n= 2) at a pressure of ∼300 MPa, possibly because of a grain‐boundary sliding mechanism; the tabular‐grained material showed Newtonian diffusional creep under similar conditions.
Processing and Properties of Ti(C,N)–WC‐Based Materials
Authors: Bellosi Alida , Medri Valentina , Monteverde Frédéric
Published: January 2009

Two Ti(C,N)–WC powder mixtures, one containing 0.88 wt% Co and the other 6.2 wt% Ni + 2.9 wt% Co, were fabricated by different routes: pressureless and gas‐pressure sintering in argon and nitrogen, and hot‐pressing under vacuum. The microstructures of all the sintered samples consisted of grains with a core/rim structure, the core being Ti(C,N) and the rim (Ti,W)(C,N). An inner rim also was present at the core/rim interface. The more highly doped materials also had an intergranular Ni‐Co‐Ti‐W binder phase. The compositions and cell parameters of the hard phases, as well as of the binder, were analyzed. The nitrogen partial pressure in the sintering furnace was the main factor that influenced grain growth and phase composition. In fact, sintering under argon enhanced grain growth and was accompanied by a lower tungsten content in the rim. The influence of the microstructure on some mechanical properties (hardness, flexural strength, toughness, and Young's modulus) also was investigated. Flexural‐strength values up to 1550 MPa at room temperature and 1200 MPa at 800°C, and fracture‐toughness values up to 8 MPa·m1/2 were measured, depending on the starting composition and processing conditions.
Incorporation of Aliovalent Dopants into the Bismuth‐Layered Perovskite‐Like Structure of BaBi4Ti4O15
Authors: Makovec Darko , Pribošic Irena , Samardžija Zoran , Drofenik Miha
Published: January 2009

The solid solubility of the aliovalent dopants Fe3+ and Nb5+ in the BaBi4Ti4O15 compound, a member of the family of Aurivillius bismuth‐based layer‐structure perovskites, has been studied using quantitative wavelength‐dispersive spectroscopic microanalysis (SEM/EPMA) in combination with X‐ray powder diffractometry (XRPD). The samples with nominal (starting) compositions corresponding to the chemical formulas BaBi4Ti4–4XFe4XO15 and BaBi4Ti4–4XNb4XO15 were prepared by hot forging a mixture of BaTiO3 and Bi4Ti3O12 with additions of Fe2O3 or Nb2O5 followed by a long annealing at 1100°C. The study showed that an excess charge introduced into the structure by the substitution of Ti4+ ions with aliovalent dopants was preferentially compensated by a change in the ratio of Ba2+ to Bi3+ ions in the host structure according to the general formulas of the solid solutions Ba1–4XBi4+4XTi4–4XFe′4XO15 and Ba1+4XBi4–4XTi4–4XNb·4XO15.
Mesoscopic Nonlinear Elastic Modulus of Thermal Barrier Coatings Determined by Cylindrical Punch Indentation
Authors: Eldridge Jeffrey I. , Zhu Dongming , Miller Robert A.
Published: January 2009

Cylindrical punch indentations are performed to determine the effective modulus of a plasma‐sprayed ZrO2–8 wt% Y2O3 thermal barrier coating (TBC) as a function of coating depth. Cylindrical punch indentations offer significant advantages over pointed (Vickers, Berkovich, or Knoop) indentations for materials that do not exhibit linear elastic behavior. Cyclic loading with a cylindrical punch clearly shows the TBCs to exhibit nonlinear elastic behavior with significant hysteresis that is related to the compaction and internal sliding within the plasma‐spray splat microstructure. Also, the effect of a high‐heat‐flux laser treatment is shown to produce a gradient both in the effective TBC modulus and degree of loading/unloading hysteresis with depth.
Effect of ethanol application on post‐luting to intraradicular dentine
Authors: Carvalho C. A. , Cantoro A. , Mazzoni A. , Goracci C. , Breschi L. , Ferrari M.
Published: January 2009

Aim  To examine the effect of the application of an ethanol rinse before luting fibre posts to intraradicular dentine with etch‐and‐rinse adhesive systems by means of push‐out bond strength evaluation and scanning electron microscopic (SEM) analysis.

Methodology  Fibre posts were luted to single‐canal premolars using Dual Link as a luting agent in combination with a three‐step (All Bond 2) or a two‐step (One Step Plus) etch‐and‐rinse adhesive system, which were applied as per manufacturers’ instructions (control) or with the additional rinse of ethanol on acid‐etched dentine prior to the bonding procedures (experimental). Bonded specimens were sectioned into 1‐mm‐thick slabs and subjected to push‐out bond strength testing. In addition, specimens from each group were processed for SEM analysis. Data were analysed by Kruskal–Wallis followed by Dunn’s post hoc test at P = 0.05.

Results  Push‐out bond strength of All Bond 2 was significantly increased if the adhesive was applied on ethanol‐saturated dentine (P < 0.05), whilst no significant difference (P > 0.05) was detected amongst experimental and control groups for One Step Plus. Irrespective of the adhesive, the SEM analysis revealed good impregnation patterns when both bonding techniques were employed.

Conclusions  The use of the additional ethanol rinse on acid‐etched dentine revealed higher bond strength of All Bond 2 when compared with the control application procedure, used in combination with a resin‐based cement to lute fibre posts into the dowel space. However, no bond strength improvements were detected using One Step Plus. Further investigations are needed to develop a clinically applicable ethanol/bonding/luting technique.
SAAG‐4 is a novel mosquito salivary protein that programmes host CD4+ T cells to express IL‐4
Authors: BOPPANA V.D. , THANGAMANI S. , ADLER A.J. , WIKEL S.K.
Published: January 2009

Mosquitoes represent the most important vector for transmitting pathogens that cause human disease. Central to pathogen transmission is the ability to divert the host immune system away from Th1 and towards Th2 responsiveness. Identification of the mosquito factor(s) critical for programming Th2 responsiveness should therefore lead to strategies to neutralize their function and thus prevent disease transmission. In the current study, we used a TCR transgenic adoptive transfer system to screen gene products present in the saliva of the mosquito Aedes aegypti for their ability to programme CD4 T cells to express the signature Th2 cytokine IL‐4. The clone SAAG‐4 encodes a secreted protein with a predicted size of 20 kDa whose function has previously been uncharacterized. Notably, SAAG‐4 reduced host CD4 T cell expression of the signature Th1 cytokine IFN‐γ while simultaneously increasing expression of IL‐4. SAAG‐4 is therefore the first identified mosquito factor that can programme Th2 effector CD4 T cell differentiation.
A new HLA‐B*35 allele, B*3589, detected in a Malaysian individual
Authors: Phipps M. , Jinam T.
Published: January 2009

A novel human leukocyte antigen‐B allele officially named B*3589, was found in an indigenous individual of Jehai ethnicity when sequencing was performed to investigate human genome variation in a research project. B*3589 differs form B*3505 in a point mutation at codon 169 (CGC to TGC) resulting in an amino acid change from Arg to Cys.
Characterisation and changes in the antioxidant system of chloroplasts and chromoplasts isolated from green and mature pepper fruits
Authors: Martí M. C. , Camejo D. , Olmos E. , Sandalio L. M. , Fernández‐García N. , Jiménez A. , Sevilla F.
Published: January 2009

Purification and characterisation of pepper (Capsicum annuum L) chloroplasts and chromoplasts isolated from commercial green, red and yellow mature fruits were undertaken. Induction of the synthesis of several antioxidants in organelles isolated from mature fruits was found. The ultrastructure of organelles and the presence and activity of SOD isozymes and enzymes involved in the ASC‐GSH cycle, together with the non‐enzymatic antioxidant content and some oxidative parameters, were analysed. It was found that lipids, rather than proteins, seem to be a target for oxidation in the chromoplasts. The ascorbate and glutathione contents were elicited during differentiation of chloroplasts into chromoplasts in both red and yellow fruits. The activity of SOD and of components of the ASC‐GSH cycle was up‐regulated, suggesting that these enzymes may play a role in the protection of plastids and could act as modulators of signal molecules such as O2˙− and H2O2 during fruit maturation. The presence of an Mn‐SOD in chromoplasts isolated from yellow pepper fruits was also investigated in terms of structural and antioxidant differences between the two cultivars.
The Obsolescence of Computational Formulae
Authors: Muttart Daved M.
Published: January 2009

Computational formulae are a throwback to a time when computers were not widely available. Today their teaching obscures important underpinnings of statistical theory and practice.
Keyed Fantasies: Music, the Accordion and the American Dream in Stroszek and Schultze Gets The Blues
Authors: Hauze Emily
Published: January 2009

The strange body of the accordion, breathing, undulating, strapped to the chest of its player, is among the many striking elements linking Werner Herzog's Stroszek (1976) and Michael Schorr's Schultze gets the blues (2003). This paper considers Schultze to be a complex response to Herzog's film, using the accordion as a link between German and American culture as well as between contemporary German cinema and its towering predecessors in New German Cinema. Both Stroszek and Schultze are interested in some strain of the ‘American Dream’: Stroszek hopes to find wealth and happiness, and Schultze seeks a certain ethnic spice found within the ‘melting pot’ of American culture. In both cases, the complex machinery of the accordion is a metaphor for dreams that might be realised in America and for the mobility required to realise them. In tracing the link between these two films, my paper investigates ways in which music is bound to cultural landscapes, and to what extent a new cultural identity can be attained through one's relationship to musical sound. For Stroszek, and, more successfully, for Schultze, the accordion is a symbol of an intact and mobile body capable of crossing cultural boundaries.
Evaluation of effects of hydroquinone on pigmentation by spectroscopy image analysis
Authors: Ohe Masahiko , Inui Madoka , Kishioka Akiko , Yonei Nozomi , Yamamoto Yuki , Furukawa Fukumi
Published: January 2009

Generally, depigmentation efficacy is evaluated by analyzing the L* value of skin to which the objective agent has been applied. However, in this method, slight inflammation and blood circulation affect the brightness, and then disturb the evaluation. So novel method that is able to quantitate melanin coloration accurately has been required. In this report, we modified the image‐processing method that was devised by Takiwaki et al. Our method can evaluate pigmentation degree and area quantitatively. Using this method, we evaluated the availability of hydroquinone agent, which has high whitening effectiveness clinically; in addition, we examined the validity of this method.
Salvia somalensis essential oil as a potential cosmetic ingredient: solvent‐free microwave extraction, hydrodistillation, GC–MS analysis, odour evaluation and in vitro cytotoxicity assays
Authors: Villa C. , Trucchi B. , Bertoli A. , Pistelli L. , Parodi A. , Bassi A.M. , Ruffoni B.
Published: January 2009

Synopsis

Salvia somalensis Vatke, a wild sage native of Somalia, has been studied with the aim of assessing the potential cosmetic application of its essential oil, recovered from fresh aerial parts by solvent‐free microwave extraction – SFME. To evaluate the efficiency and reliability of this ecofriendly procedure, the recovery of the essential oil was also processed by conventional hydrodistillation (HD) and the results compared. The essential oils obtained by both SFME and HD were analysed by gas chromatography–mass spectrometry using apolar and polar capillary columns. The essential oil recovered by SFME was submitted to an odour evaluation that revealed peculiar olfactive characteristics interesting in alcoholic male perfumery and body detergents.In vitro cytotoxicity assays were carried out using NCTC 2544 human keratinocytes as target cells. The oil displayed slight cytotoxic effects, which were three orders of magnitude lower than those found for sodium dodecyl sulphate positive control. The promising results in terms of chemical composition, scent and safety seem to indicate this essential oil as an interesting potential functional ingredient useful in a cosmetic context.
Development of a minimally invasive epidermal abrasion device for clinical skin sampling and its applications in molecular biology
Authors: Lee J.‐M. , Carson R. , Arce C. , Mahajan M. , Lobst S.
Published: January 2009

Synopsis

A new abrasion tool (US patent US7087063 B2) has been developed for collecting skin epidermal samples. This device includes a central shaft that holds the probe in a split chuck. Of the variety of probe designs tested, the laser‐cut hollow tube (HT) probe abraded the basal layer of the epidermis most consistently, resulting in representative epidermal skin samples. Compared with traditional clinical methods, the abrasion method allows for high‐throughput epidermal skin collection with minimal invasiveness to the volunteer subjects. A large number of abrasion samples have been collected in various clinical studies with no adverse effects observed. Epidermal abrasion, when used appropriately and with the optimized probes, can yield high quality tissue samples that are representative of the epidermis. A sufficient quantity of RNA and protein can be obtained for many subsequent molecular and biochemical applications. Because of its minimal invasiveness and high‐throughput nature, the abrasion method can be a valuable tool used to investigate the efficacy of topical applications of skin care products.
The National Evaluation of Senior Mentor Programs: Older Adults in Medical Education
Authors: Eleazer G. Paul , Stewart Thomas J. , Wieland G. Darryl , Anderson M. Brownell , Simpson Deborah ,   for the Steering Committee of the National Evaluation of Senior Mentor Programs
Published: January 2009

OBJECTIVES: To identify models for senior mentor programs (SMPs), critical factors in program development, achievement of goals and objectives, effect on medical school environment, and future of programs.

DESIGN: Ten SMPs were systematically selected to represent a variety of medical schools, geographic regions, and program types. The National Senior Mentor Program Evaluation relied upon archived data within the programs and new data collected during site visits. Archived data included internally conducted program evaluations, student course evaluations, and survey and focus group results. Site visit data were collected from key informant interviews with program staff and faculty, medical school leadership and students, and older adults serving as mentors.

SETTING: Ten U.S. medical schools with SMPs.

PARTICIPANTS: Evaluation participants at each site included program faculty, key medical school administrators, participating students, and mentors.

MEASUREMENTS: Program evaluation.

RESULTS: All 10 programs demonstrated a positive effect on student attitudes toward older adults. Student acceptance of the programs was strong, and mentor acceptance and support were extraordinary. Eight of the 10 programs were operating in 2008 and having considerable effect on medical school environments. Most of the operating programs expect to be continuing for 5 or more years into the future.

CONCLUSIONS: The findings of the national evaluation point toward continuation and likely growth of the senior mentor phenomenon in U.S. medical education.
Mortality, Dementia, and Apolipoprotein E Genotype in Elderly White Women in the United States
Authors: Little Deborah M. , Crooks Valerie C. , Petitti Diana B. , Chiu Vicki , Schellenberg Gerard D. , Slezak Jeff M. , Jacobsen Steven J.
Published: January 2009

OBJECTIVES: To assess the risk of death in relation to apolipoprotein E (APOE) genotype and to evaluate how APOE genotype interacts with dementia and with other major medical conditions to affect survival.

DESIGN: A 6‐year prospective cohort study of dementia, APOE genotype and survival.

SETTING: Health maintenance organization in southern California.

PARTICIPANTS: One thousand eight hundred forty‐two white women aged 75 and older.

MEASUREMENTS: Dementia was determined using a multistage assessment procedure, medical record, and death certificate review.

RESULTS: With women with the APOE 3/3 genotype as the referent, age‐adjusted hazard ratios (HRs) for death according to genotype were 1.25 (95% confidence interval (CI)=1.00–1.56) for APOE 2/4, 3/4, or 4/4 and 0.83 (95% CI=0.62–1.13) for APOE 2/3 or 2/2. Survival was associated with APOE genotype (log rank test P=.02). Women with the APOE 2/4, 3/4, or 4/4 genotype died at an earlier age, and those with APOE 2/2 or 2/3 died later than those with the APOE 3/3 genotype. After adjustment for age, education, and hormone use, HRs for death were significantly higher in women with the APOE 2/4, 3/4, or 4/4 genotype who developed dementia (HR=3.74; 95% CI=2.81–4.99) and the APOE 2/3 genotype (HR=3.23; 95%=CI=1.97–5.28) than in women without dementia and the APOE 3/3 genotype. The HRs for death were greater with other medical conditions, but no interaction with any APOE genotype was found.

CONCLUSION: In this population of elderly women, although having at least one ɛ4 allele increased the chances of an earlier death, having dementia increased the risk of death regardless of APOE genotype.
Factors Limiting Equilibrium in Fabricating a Simple Ferroelectric Oxide: BaTiO3
Authors: Lee Soonil , Randall Clive A. , Liu Zi‐Kui
Published: January 2009

This paper demonstrates a number of features that can contribute to BaTiO3 being perturbed from an equilibrium condition. The BaTiO3 synthesis study was conducted with a modified citrate process, but the kinetic aspects limiting the equilibrium state are believed to be general to any processing route. The equilibrium conditions can be determined through a detailed analysis of the paraelectric–ferroelectric phase transition data measured by differential scanning calorimeter. Broadened and multiple latent heat peaks are found indicating a distribution of slightly different ferroelectric transition temperatures for nonequilibrated BaTiO3 materials. A number of factors have been found that limit the equilibrium conditions, and these include time at formation conditions of temperature and oxygen partial pressure, a second phase BaCO3, and the rapid nucleation of a BaTi2O5 phase on quenching to room temperature from temperatures in and around 1250°C. All of these nonequilibrium factors that occurs at high temperature lead to the ferroelectric phase transition having multiple phase transitions, owing to regions of the BaTiO3 having different partial Schottky concentrations.
Abstract 2.0: If We Are All Shouting, Is There Anyone Left To Listen?
Authors: NAFUS DAWN , DE PAULA ROGERIO , ANDERSON KEN
Published: January 2009

This paper explores notions of ‘voice’ as it relates to Web 2.0. We begin by tracing the social meanings of Web 2.0 technologies Brazil. There the notions of ‘voice’ as conceived of in the American media are absent, yet significant collective action took place online through a kind of speaking out. Next the paper describes the conflation of voice with a notion of social networks to explain how the American media misread the Brazilian action. This is achieved by an incredible plasticity and abstraction of the Web 2.0′ construct, which flattens otherwise qualitatively meaningful distinctions. This puts us on some ground to raise the issue of how abstractions might become relationships. This, we argue, is evidenced both in terms of how Brazilians might interpret online relationships, and how Web 2.0 hype betrays a politics of abstraction at work in the wider economy.
Ethnography and music. Disseminating ethnographic research inside organizations
Authors: LUIS ARNAL , ROBERTO HOLGUIN
Published: January 2009

In the applied context of ethnography its value depends not only on the quality of the research product alone but also on how it is received by the business audience. This paper presents some variables that describe and hope to overcome common barriers to the appropriate reception of ethnographic research in the business context. We are using music as a metaphor to the discussion of barriers and research use.
An Economy of Knowledge: Research, Architectural Practice and Knowledge (in) Translation
Authors: MAHER ANDREW , MEWBURN INGER
Published: January 2009

How does new knowledge ‘flow’ within an organisation? In this paper we report upon a case study in which ethnography is employed to render visible the ‘knowledge transfer’ (strategically redefined as ‘knowledge translation’) occurring between a PhD researcher and the members of the organisation in which he is ‘embedded’. In this case the PhD student is located within an architectural firm and an industry context that is not accustomed to housing researchers in its midst. The path of knowledge flow, or rather its translation, is not found to be smooth. Knowledge ‘flow’ happens only in leaks and trickles through the organisation. We discuss the implications of this case for how ethnographic research in a business context might be communicated to an audience who do not necessarily value scrutiny of this nature.
Research to Reality: A Business Perspective
Authors: Phillips Daja
Published: January 2009

Ricob Innovations discovers unmet customer needs and designs and deploys hardware, software and service solutions to those needs through an interdisáplinary design process predicated on active customer participation. Some of our findings lead to new value propositions on which Ricoh planners investigate entirely new businesses. We attribute our success to our ability to translate our findings into actionable, risk‐sensitive business cases tested and improved with active customer participation. We collaborate closely to weave our activities into critical product planning milestones, but retain ownership for the process of site selection, research, synthesis, business modeling and transfer to ensure success. As a result, Ricoh launched a new product line based on our research, in less than a year and our methodology is now used by other Ricoh research groups to serve Ricob's European and Japanese markets. The first half of this paper outlines the organization and methodology used to identify customer needs, and prove the associated value of a customer‐design solution. The second half comments on some of the techniques we use to filter and package our results for optimal impact on the product groups.
Evaluation of the Neuroprotective Efficacy of Newly Developed Oximes (K206, K269) and Currently Available Oximes (Obidoxime, HI‐6) in Cyclosarin‐Poisoned Rats
Authors: Kassa Jiri , Karasova Jana Zdarova , Bajgar Jiri , Tesarova Sandra , Kuca Kamil , Musilek Kamil
Published: January 2009

Abstract:  The neuroprotective effects of newly developed oximes (K206, K269) and currently available oximes (obidoxime, HI‐6) in combination with atropine in rats poisoned with cyclosarin were studied. The cyclosarin‐induced neurotoxicity was monitored using a functional observational battery at 24 hr following cyclosarin challenge. The results indicate that a newly developed oxime K206 is able to counteract cyclosarin‐induced neurotoxicity while the neuroprotective potency of another newly developed oxime (K269) is negligible. The neuroprotective efficacy of K206 is markedly higher than commonly used obidoxime; nevertheless, its potency to eliminate cyclosarin‐induced neurotoxicity is slightly lower compared to the oxime HI‐6. Thus, a newly developed oxime K206 seems to be a better oxime for the antidotal treatment of cyclosarin poisonings than obidoxime due to higher neuroprotective potency although the oxime HI‐6 is still the most suitable oxime for the antidotal treatment of acute poisonings with cyclosarin.
Effortless Application of the Method of Lines for the Inverse Estimation of Temperatures in a Large Slab With Two Different Surface Heating Waveforms
Authors: Campo Antonio , Ho John
Published: January 2009

The boundary inverse heat conduction problem (BIHCP) deals with the determination of the surface heat flux or the surface temperature from measured transient temperatures inside a conducting body where the initial temperature is known. This work addresses a BIHCP related to the spatiotemporal heat conduction in a large slab when a time-variable heat flux is prescribed at an exposed surface and the other surface is thermally insulated. Two different heating waveforms are studied: a constant heat flux and a time-dependent triangular heat flux. The numerical temperature-time history at the insulated surface of the large slab provides the “temperature-time measurement” with one temperature sensor. Framed in the theory of the method of lines (MOL) first and employing rudimentary concepts of numerical differentiation later, the main objective of this paper is to develop a simple computational methodology to estimate the temporal evolution of temperature at the exposed surface of the large slab receiving the two distinct heat fluxes. In the end, it is confirmed that excellent predictions of the surface temperatures versus time are achievable for the two cases tested while employing the smallest possible system of two heat conduction differential equations of first-order.
Turbulent Rotating Rayleigh–Benard Convection: Spatiotemporal and Statistical Study
Authors: Husain A. , Baig M. F. , Varshney H.
Published: January 2009

The present study involves a 3D numerical investigation of rotating Rayleigh–Benard convection in a large aspect-ratio (8:8:1) rectangular enclosure. The rectangular cavity is rotated about a vertical axis passing through the center of the cavity. The governing equations of mass, momentum, and energy for a frame rotating with the enclosure, subject to generalized Boussinesq approximation applied to the body and centrifugal force terms, have been solved on a collocated grid using a semi-implicit finite difference technique. The simulations have been carried out for liquid metal flows having a fixed Prandtl number Pr=0.01 and fixed Rayleigh number Ra=107 while rotational Rayleigh number Raw and Taylor number Ta are varied through nondimensional rotation rate (Ω) ranging from 0 to 104. Generation of large-scale structures is observed at low-rotation (Ω=10) rates though at higher-rotation rates (Ω=104) the increase in magnitude of Coriolis forces leads to redistribution of buoyancy-induced vertical kinetic energy to horizontal kinetic energy. This brings about inhibition of vertical fluid transport, thereby leading to reduced vertical heat transfer. The magnitude of rms velocities remains unaffected with an increase in Coriolis forces from Ω=0 to 104. An increase in rotational buoyancy (Raw), at constant rotation rate (Ω=104), on variation in Raw/Ta from 10−3 to 10−2 results in enhanced breakup of large-scale structures with a consequent decrease in rms velocities but with negligible reduction in vertical heat transport.
Thermal Transport Characteristics of Mixed Pressure and Electro-Osmotically Driven Flow in Micro- and Nanochannels With Joule Heating
Authors: Chen Chien-Hsin
Published: January 2009

This study investigates convective transport phenomena of combined electro-osmotic and pressure-driven flow in a microchannel subject to constant surface heat flux, with Joule heating effect taken into account. The governing system of equations includes the electric potential field, flow field, and energy equations. Analytical solutions are obtained for constant fluid properties, while numerical solutions are presented for variable fluid properties. For constant properties, the problem is found to be governed by three ratios: the length scale ratio (the ratio of Debye length to half channel height), the velocity scale ratio (the ratio of pressure-driven velocity to electro-osmotic velocity), and the ratio of Joule heating to surface heat flux. A small length scale ratio corresponds to a microchannel, while finite length scale ratio represents a nanochannel. For electro-osmotic flow only, the momentum transport is solely a function of the length scale ratio. For combined electro-osmotic and pressure-driven flow, the velocity profile and therefore the friction factor depend on both the length scale ratio and the velocity scale ratio. Assuming a thermally fully developed flow, analytical expressions for the normalized temperature profile and Nusselt number are developed. The representative results for the friction factor, normalized temperature profile, and Nusselt number are illustrated for some typical values of the three ratios. For purely electro-osmotic flow, it is found that the Nusselt number increases with decreasing ε, approaching the value for slug flow as the length scale ratio approaches zero. For mixed flow with a given length scale ratio, the results show that the Nusselt number decreases with the velocity scale ratio, approaching the classical Poiseuille flow as the velocity scale ratio approaches infinite. When the effects of variable fluid properties are included in the analysis, numerical solutions are generated to explore the influence of thermal conductivity and viscosity variations with local temperature on the hydrodynamic and thermal characteristics of the fluid. These temperature-dependent property variations would initially develop pressure-driven flow, and correspondingly the dimensionless velocity and volume flow rate increase to account for such variations. The friction factor reduces considerably with viscosity variation, while the Nusselt number increases gently. Although the influence of thermal conductivity variation on the hydrodynamic characteristics is not impressive, it has certain impact on the heat transfer results; more specifically, increasing the conductivity variation will produce a sensible increase in Nusselt number but a small decrease in the normalized temperature.
Influence
of Near Hole Pressure Fluctuation on the Thermal Protection of a Film-Cooled Flat
Plate
Authors: Burdet André , Abhari Reza
S.
Published: January 2009

The pulsation of film cooling jets in turbines is driven by the near hole pressure fluctuation caused by the deterministic interaction of stator/rotor blade rows. Jet pulsation is characterized by the coolant near hole reduced frequency Ωc and the pulsation amplitude coefficient Ψ. The fluctuation of the near hole pressure is simulated by setting a time-varying signal of static pressure for the outlet boundary condition of a film-cooled flat plate configuration. It is observed that the fluctuation of the near hole pressure influences the blowing ratio, hence the thermal protection downstream of the injection site. For a low mean blowing ratio (BR¯=0.75), low-medium pulsation frequencies (Ωc⩽0.10) are found to be slightly detrimental to the thermal protection versus a steady injection. On the contrary, for high pulsation frequencies (Ωc⩽0.17), the thermal protection becomes better due to periodic jet disintegration into the wall surface caused by a higher level of transverse kinetic energy of the jet pulse. In addition, the overlapping of jet pulses appears to help the constant temporal spreading of coolant over the wall surface. For a higher mean blowing ratio (BR¯=1.25), jet pulsation enhances lift-off so that the thermal protection is, in general, worse compared to a steady injection. Overall, the range of jet pulsation presented in this study affects moderately the thermal protection of the downstream surface.
Co-Combustion of Biomass and Coal in Circulating Fluidized Bed: Modeling and Validation
Authors: Ada´nez Juan , de Diego Luis F. , Gaya´n Pilar , Garci´a-Labiano Francisco , Cabanillas Andre´s , Bahillo Alberto
Published: January 2009

In this work carbon combustion efficiencies in circulating fluidized bed combustion (CFBC) when co-firing biomass and coal mixtures were studied. Experimental results were obtained from the combustion of two kind of coals with a forest residue (Pine bark) in a CBF pilot plant (0.3MWth) with 20-cm i.d. and 6.5-m height. The effect of operating conditions such as percentage of biomass in the feed, temperature, excess air, air velocity and percentage of secondary air on carbon combustion efficiency was studied. A mathematical model for the co-combustion of coal and biomass in a circulating fluidized bed boiler has been developed. The riser is divided in three zones with different hydrodynamic characteristics: bottom, splash and freeboard. The bottom bed has a constant voidage, determined by a modified two-phase theory. The solids are considered in perfect mixing and the gas in plug flow. The voidage in the splash region follows an exponential decay model. In the freeboard region, the solids and the gas are in plug flow, and a core-annulus structure is considered. Devolatilization of solid fuels is modeled with a particle reaction model which allows to determine the volatiles generation rate as a function of time and operating conditions. Kinetics of char combustion is modeled with the shrinking particle model with mixed control by chemical reaction and gas film diffusion, assuming that the ashes separate once formed. To consider that the char particles are a mixture of coal and biomass char particles, a weighted average combustion rate is defined taking into account the individual combustion rates. Population balances of char particles in the different regions were developed to calculate carbon concentrations. The developed model can predict the different gas concentrations along the riser, such as oxygen, SO2, CO, CH4, etc..., and the carbon combustion efficiency. The experimental results of carbon combustion efficiencies and gas emissions were compared with those predicted by the model and a good correlation was found for all the conditions used.
Assessment of Sorbent Reactivation by Water Hydration for Fluidized Bed Combustion Application
Authors: Montagnaro Fabio , Salatino Piero , Scala Fabrizio , Wu Yinghai , Anthony Edward , Jia Lufei
Published: January 2009

Disposal of FBC solid residues currently represents one of the major issues in FBC design and operation, and contributes significantly to FBC operating cost. This issue has triggered research activities on the enhancement of sorbent utilization for in-situ sulfur uptake. The present study addresses the effectiveness of the reactivation by liquid water hydration of FB spent sorbents. Two materials are considered in the study, namely bottom ash from the operation of a full-scale utility FB boiler and the raw commercial limestone used in the same boiler. Hydration-reactivation tests were carried out at temperatures of 40°C and 80°C and for curing times ranging from 15min to 2d, depending on the sample. The influence of hydration conditions on the enhancement of sulfur utilization has been assessed. A combination of methods has been used to characterize the properties of liquid water-hydrated materials.
GlidArc-Assisted Production of Synthesis Gas Through Partial Oxidation of Natural Gas
Authors: Czernichowski Albin , Wesolowska Krystyna
Published: January 2009

Natural gas is reformed with air in a presence of high-voltage discharges (called GlidArc plasma) that assist the Partial Oxidation. Electric consumption for this non-catalytic reformer is less than 2% of the output H2+CO energy content. Recycling such a small portion of energy is, in our opinion, an acceptable compromise as active (and also very simple) GlidArc discharges play a role of an igniter and homogeneous phase catalyst; they also stabilize a post-plasma zone of our reformer. Here presented bench-scale 1-Liter reactor works at atmospheric pressure and needs less than 100 W of electric assistance to produce up to 1.4 m3(n)/h of pure H2+CO corresponding to about 4.5 kW of electric power of an ideal Fuel Cell fed by such SynGas. Up to 96% of natural gas is converted at up to 63% energetic efficiency and the total absence of soot. Our previous experiments with highly Sulfur-polluted feeds let us claim that our technology can be directly used at any H2S level in natural gas.
Influence of Radiative Heat Transfer on Variation of Cell Voltage Within a Stack
Authors: Burt A. C. , Celik I. B. , Gemmen R. S. , Smirnov A. V.
Published: January 2009

In this study, a numerical investigation of cell-to-cell voltage variation by considering the impact of flow distribution and heat transfer on a stack of cells has been performed. A SOFC stack model has been previously developed to study the influence of flow distribution on stack performance (Burt, et al., 2003). In the present study the heat transfer model has been expanded to include the influence of radiative heat transfer between the PEN (positive electrode, electrolyte, negative electrode) and the neighboring separator plates. Variations in cell voltage are attributed to asymmetries in stack geometry and nonuniformity in flow rates. Simulations were done in a parallel computing environment with each cell computed in a separate (CPU) process. This natural decomposition of the fuel cell stack reduced the number of communicated variables thereby improving computational performance. The parallelization scheme implemented utilized a message passing interface (MPI) protocol where cell-to-cell communication is achieved via exchange of temperature and thermal fluxes between neighboring cells. Inclusion of radiative heat transfer resulted in more uniform temperature and voltage distribution for cases of uniform flow distribution. Non-uniform flow distribution still resulted in significant cell-to-cell voltage variations.
Oxygen: Aluminum Fuel Cells and Most Practical Fields of Their Applications
Authors: Farmakovskaya A. A. , Popov V. V. , Sevruk S. D. , Tumanov B. I. , Udaltsov V. G.
Published: January 2009

On the total combination of their power, electric, economic, operating and ecological characteristics fuel cells (FC) on the base of oxygen (air) - aluminum (AA) electrochemical system are one of the most effective fuel cells. On their power/mass performances they are worse only the oxygen-hydrogen FC and some types of FC with the lithium anode. It is easy to recharge AA FC by means of the mechanical replacement of the working components after their expenditure. AA FC storage period is not less then ten years without degradation of their characteristics. Thus it is a prospective current source with a repeated operation. It is distinguished by the high power performances, long storage period and ecological cleanness as during their exploitation, as during their producing and utilization of the waste FC and the products of the reactions. The authors developed fundamental researches of the processes which take place at the systems and assemblies of power plants (PP) with AA FC. These researches allowed to eliminate the basic defects of AA FC which blocked their practical application. Autonomous current sources on the AA FC base can be effectively applied for the different users power supply in the main supply absence conditions. The basic application fields: telecommunication systems, transport, rescue-emergency parties and so forth. We created the aluminum-air fuel cells power plants (PP) with the alkaline and salt electrolytes with the different additions and special developed anode alloys. They have the wide ranged capacities from the unites of W up to hundreds of kW.
“Floating Scroll” Technology for Fuel Cell Air Management System
Authors: Ni Sam
Published: January 2009

The performance and overall efficiency of the entire fuel cell system is very dependent on the air management subsystem. Unfortunately, no compressor-expander module technologies are available that simultaneously meet all of the air supply requirements of Polymer Electrolyte Membrane fuel cell systems. Scroll Laboratories has developed innovative oil-free scroll devices as compressor, expander and vacuum pump — the “floating scroll”. The “floating scroll” uses a dual-scroll structure and introduces a mechanism called synchronizer. This mechanism enables the orbiting scroll with full compliant ability, namely axial and radial. The floating scroll scheme balances all pressure and centrifugal forces within the scroll, minimizing forces on contacting surfaces to maintain excellent seal and essentially zero or minimum wear. The orbiting scrolls are literally floating between fixed scrolls during high speed orbiting motion. In the floating scroll, the compression and/or expansion processes take place without lubrication and cooling from injecting lubricant and coolant. The floating scroll technology is the answer to the needs of air management system for fuel cell systems.