bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of systemic carbon dioxide production during cardiopulmonary bypass: a comparison of Fick’s principle with oxygentor exhaust output
Authors: Alston R Peter , Glassford Neil J , Torrie Amanda
Published: January 2005

Theoretically, systemic carbon dioxide (VCO2) production should be an alternative means to systemic oxygen uptake (VO2) for estimating the global efficacy of cardiopulmonary bypass (CPB). This study compared two methods of estimating VCO2: Fick’s principle and oxygenator exhaust carbon dioxide (CO2) output. Both of these estimates were then compared with VO2. Fifty-one patients (39 male and 12 female) undergoing elective cardiac surgery requiring CPB were studied. Blood sampling was performed and measurements recorded during active cooling, environmental cooling/stable hypothermia and during rewarming. Blood samples were measured for CO2 tension from which content was estimated. VCO2 was calculated as the product of the arteriovenous difference in CO2 content and pump flow rate (Fick’s principle), or the fresh gas flow rate and concentration of the oxygenator exhaust CO2 (output technique). Over all measurements, method comparison analysis revealed a large mean bias of 41 (95% confidence intervals (CI) 32-50) mL/min with very wide limits of agreement (-23, 105 mL/min). Regression analysis found that the bias was also proportional to the size of measurement (β=0.75 (95% CI 0.55, 0.95)). Although both methods of VCO2 correlated significantly with VO2 ( p<0.01), regression analysis found that the coefficients (β) of both techniques had wide CI (Fick’s principle: β=1.37 (95% CI 1.20, 1.54); output technique: β=0.58 (95%CI 0.44, 0.71)). In conclusion, both techniques of VCO2 cannot be used interchangeably, and both are imprecisely related to VO2 as estimated by Fick’s principle.
Effects of N-acetylcysteine on pulmonary function in patients undergoing coronary artery bypass surgery with cardiopulmonary bypass
Authors: Eren Nesimi , Çakir Ömer , Oruc Ahmet , Kaya Ziya , Erdinc Levent
Published: January 2005

Cardiopulmonary bypass (CPB) has been implicated in causing poor pulmonary gas exchange postoperatively in patients undergoing coronary artery bypass grafting (CABG) procedures. In this prospective, randomized, double-blind, placebo-controlled study, we examined the pulmonary effects of N-acetylcysteine (NAC) in patients undergoing CABG. Twenty patients undergoing elective CABG and early tracheal extubation were randomized into two groups. Group I (ten patients) received a physiologic salt solution as a placebo in a continuous intravenous infusion for one hour before CPB and 24 hours after CPB; Group II (ten patients) received 100 mg/kg NAC intravenously for one hour before CPB and 40 mg/kg/day at 24 hours after CPB. Perioperative hemodynamic and pulmonary data were recorded. Postoperative tracheal extubation was accomplished at the earliest appropriate time. The postoperative clinical course was similar in the two groups. Both groups exhibited significant postoperative increases in A-a oxygen gradient ( p<0.01), but patients in Group II exhibited significantly lower increases in postoperative A-a oxygen gradient ( p<0.006). Other hemodynamic and pulmonary data (pulmonary capillary wedge pressure, pulmonary vascular resistance (PVR), cardiac index (CI), shunt flow, dynamic lung compliance and static lung compliance) exhibited no differences between the groups. There was no significant difference in terms of intubation time. The malondialdehyde (MDA) increase in Group II following CPB was found to be significantly lower than in Group I (p=0.043). This clinical study reveals that administration of NAC to patients undergoing elective CABG with CPB improves systemic oxygenation. There was no effect in other pulmonary parameters and in terms of intubation time.
Characteristics and user acceptance of peer rating in EFL writing classrooms
Authors: Saito Hidetoshi , Fujita Tomoko
Published: January 2005

Lack of research on the characteristics of peer assessment in EFL writing may inhibit teachers from appreciating the utility of this innovative assessment. This study addressed the following research questions: (1) How similar are peer, self- and teacher ratings of EFL writing?; (2) Do students favour peer ratings?; and (3) Does peer feedback influence students’ attitudes about peer rating? Forty-seven college students studying English writing in a Japanese college were assigned to write two essays. Each essay was commented on and rated by two teachers, three peers and the writers themselves. Students also completed a five-item questionnaire about their attitudes regarding peer rating. Peer and teacher ratings were found to correlate significantly. The results of the questionnaire indicated that students had favourable attitudes towards peer rating. A regression analysis suggested that peer feedback did not influence students’ favourable attitudes about the feedback.
Effects of Buoyancy‐Driven Convection on Nucleation and Growth of Protein Crystals
Authors: NANEV CHRISTO N. , PENKOVA ANITA , CHAYEN NAOMI
Published: January 2005

Abstract:Protein crystallization has been studied in presence or absence of buoyancy‐driven convection. Gravity‐driven flow was created, or suppressed, in protein solutions by means of vertically directed density gradients that were caused by generating suitable temperature gradients. The presence of enhanced mixing was demonstrated directly by experiments with crustacyanin, a blue‐colored protein, and other materials. Combined with the vertical tube position the enhanced convection has two main effects. First, it reduces the number of nucleated hen‐egg‐white lysozyme (HEWL) crystals, as compared with those in a horizontal capillary. By enabling better nutrition from the protein in the solution, convection results in growth of fewer larger HEWL crystals. Second, we observe that due to convection, trypsin crystals grow faster. Suppression of convection, achieved by decreasing solution density upward in the capillary, can to some extent mimic conditions of growth in microgravity. Thus, impurity supply, which may have a detrimental effect on crystal quality, was avoided.
Numerical Analysis of the Depletion Zone Formation Around a Growing Protein Crystal
Authors: TANAKA HIROAKI , INAKA KOJI , SUGIYAMA SHIGERU , TAKAHASHI SACHIKO , SANO SATOSHI , SATO MASARU , YOSHITOMI SUSUMU
Published: January 2005

Abstract: It is expected that a protein depletion zone and an impurity depletion zone are formed around a crystal during protein crystal growth if the diffusion field around the crystal is not disturbed. The growth rate of the crystal may be decreased and the impurity uptake may be suppressed to result in highly ordered crystals if these zones are not disturbed. It is well known that a microgravity environment can reduce convective fluid motion, and this is thought to disturb the depletion zones. Therefore, we expect that crystals grown in space can attain better quality than those grown on the ground. In this study, we estimate the depletion zone formation numerically and discuss the results of crystallization in space experiments. In case of α‐amylase, most of the crystals form a cluster‐like morphology on the ground using PEG 8000 as a precipitant. However, in space, we have obtained a single and high‐quality crystal grown from the same sample compositions. We have measured the viscosity of the solution, the diffusion coefficient, and the growth rate of protein crystals on the ground. Applying numerical analysis to these values a significant depletion zone was expected to form mainly due to higher values of the viscosity. This might be one of the main reasons for better quality single crystals grown in space, where the depletion zone is thought to remain undisturbed. For protein crystallization experiments, salts are widely used as a precipitant. However, in that case, reduced concentration depletion zone effects can be expected because of a low viscosity. Therefore, if it is possible to increase the viscosity of the protein solution by means of an additive, the depletion zone formation effect would be enhanced to provide a technique that would be especially effective in space.
Size and Shape Determination of Proteins in Solution by a Noninvasive Depolarized Dynamic Light Scattering Instrument
Authors: CHAYEN NAOMI , DIECKMANN MATTHIAS , DIERKS KARSTEN , FROMME PETRA
Published: January 2005

Abstract: Dynamic light scattering (DLS) is a well‐known noninvasive technique for investigating interactions of protein molecules in solution. Unfortunately, DLS is not very sensitive to small size changes because covariables, such as temperature, viscosity, and refractive index, are not precisely known, or they vary as functions of an experiment run, making it difficult to resolve subtle size changes of only a few Angström. It is usually not possible, if these covariables are not systematically measured and brought into the DLS analysis, to separate monomers from dimers when both are present in solution. We present here measurements with a variant of DLS that determines rotational diffusion as well as translation diffusion. This technique, called depolarized dynamic light scattering (DDLS) is, like DLS, also an old method, but it is rarely used due to enormous practical difficulties. However, we have found that a combination of DLS with DDLS is very promising, because it allows for a rough shape determination of the molecule under study and it is more sensitive to subtle size changes. We built an instrument that overcomes some of the difficulties, and report measurements made with this instrument. One of the samples was Photosystem‐I, a membrane protein for photosynthesis. Its dimensions were determined to be 9.6 nm thick and 26 nm in diameter, values that are in good agreement with the dimensions obtained from X‐ray diffraction analysis of single crystals.
Bone Cell Survival in Microgravity: Evidence that Modeled Microgravity Increases Osteoblast Sensitivity to Apoptogens
Authors: BUCARO M A , FERTALA J , ADAMS C S , STEINBECK M , AYYASWAMY P , MUKUNDAKRISHNAN K , SHAPIRO I M , RISBUD M V
Published: January 2005

Abstract: Studies were performed to evaluate the effects of modeled microgravity on the induction of osteoblast apoptosis. MC3T3‐E1 osteoblast‐like cells were cultured in alginate carriers in the NASA‐approved high aspect ratio vessel (HARV). This system subjects the cells to a time‐averaged gravitational field (vector‐averaged gravity) to simulate low gravity conditions. Cells were cultured in the HARV for five days, and then examined for apoptosis. In simulated microgravity, the cells remained vital, although analysis of expressed genes indicated that there was loss of the mature osteoblast phenotype. Additionally, we noted that there was a loss of the mitochondrial membrane potential, a low level of the antiapoptotic protein Bcl‐2, as well as Akt protein, and the redox status of the cells was disturbed. All of these parameters indicated that vector‐averaged gravity disrupts mitochondrial function, thereby sensitizing osteoblasts to apoptosis. We then used a challenge assay to evaluate the apoptotic sensitivity of the cells subjected to vector‐averaged gravity. When challenged with staurosporine, cells subjected to vector‐averaged gravity evidenced elevated levels of cell death relative to control cell populations. Another objective of the study was to improve upon conventional carriers by using alginate encapsulation to support cells in the HARV. We have demonstrated that the alginate carrier system affords a more robust system than surface‐seeded carriers. This new system has the advantage of shielding cells from mechanical damage and fluid shear stresses on cells in the HARV, permitting carefully controlled studies of the effects of vector‐averaged gravity.
Space Radiation Transport Properties of Polyethylene‐Based Composites
Authors: KAUL R K , BARGHOUTY A F , DAHCHE H M
Published: January 2005

Abstract: Composite materials that can serve as both effective shielding materials against cosmic‐ray and energetic solar particles in deep space, as well as structural materials for habitat and spacecraft, remain a critical and mission enabling component in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density, coupled with high hydrogen content. Polyethylene‐fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of polyethylene‐fiber reinforced epoxy matrix composite 1‐5 cm thick were prepared at the NASA Marshall Space Flight Center and tested against a 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.
The Study of Devitrification Processes in Heavy‐Metal Fluoride Glasses
Authors: DUNKLEY IAN R. , SMITH REGINALD W. , VARMA SUDHANSHU
Published: January 2005

Abstract: Heavy‐metal fluoride glasses are very promising optical fiber materials because of their predicted ultralow loss and long transparency range. Although conventional silica fibers have attained their theoretical minimum loss of 0.15 dB/km, fluoride glasses have the potential to yield losses of only 0.001 dB/km. Fluoride glasses also exhibit transparency into mid‐IR frequencies, a region inaccessible to silica fibers. However, this group of glasses is very unstable to devitrification during both bulk glass synthesis and fiber‐drawing. This instability has limited their commercial exploitation to a small niche market in the laser industry. The ZBLAN glass (53ZrF4‐20BaF2‐4LaF3‐3AlF3‐20NaF) is the most promising of these materials since its fiber‐drawing region lies on the edge, or possibly just outside its crystallization region. It is believed that additional research into understanding the nucleation mechanics involved in the devitrification of fluoride glasses will lead to the development of technology to suppress such nucleation, or at least minimize the associated crystallization temperature region, allowing high optical quality fibers to be produced. It has recently been demonstrated that a microgravity environment can suppress devitrification in ZBLAN glass preform preparation, and that devitrification may be reduced when preparing ZBLAN terrestrially in a containerless facility. It is believed that the role of viscosity is critical in the devitrification mechanism of ZBLAN glass and in determining the optimum fiber‐drawing temperature. Unfortunately, viscosity data for fluoride glasses are only available above the melting point and around the glass transition. A piezoelectric viscometer has been developed and is being used to determine the missing viscosity data in the fiber‐drawing and crystallization temperature regions. Shear thinning of the glasses and/or the application of hydrostatic pressure on the glasses have been recently proposed to be responsible for devitrification during fiber‐drawing at 1 g and in reduced gravity. The study we report here is to explore the extent to which such a proposal is realistic.
Momentum Effects in Steady Nucleate Pool Boiling During Microgravity
Authors: MERTE HERMAN
Published: January 2005

Abstract: Pool boiling experiments were conducted in microgravity on five space shuttle flights, using a flat plate heater consisting of a semitransparent thin gold film deposited on a quartz substrate that also acted as a resistance thermometer. The test fluid was R‐113, and the vapor bubble behavior at the heater surface was photographed from beneath as well as from the side. Each flight consisted of a matrix of three levels of heat flux and three levels of subcooling. In 26 of the total of 45 experiments conditions of steady‐state pool boiling were achieved under certain combinations of heat flux and liquid subcooling. In many of the 26 cases, it was observed from the 16‐mm movie films that a large vapor bubble formed, remaining slightly removed from the heater surface, and that subsequent vapor bubbles nucleate and grow on the heater surface. Coalescence occurs upon making contact with the large bubble, which thus acts as a vapor reservoir. Recently, measurements of the frequencies and sizes of the small vapor bubbles as they coalesced with the large bubble permitted computation of the associated momentum transfer. The transient forces obtained are presented here. Where these arise from the conversion of the surface energy in the small vapor bubble to kinetic energy acting away from the solid heater surface, they counter the Marangoni convection due to the temperature gradients normal to the heater surface. This Marangoni convection would otherwise impel the large vapor bubble toward the heater surface and result in dryout and unsteady heat transfer.

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Development of a High‐Performance Boiling Heat Exchanger by Improved Liquid Supply to Narrow Channels
Authors: OHTA HARUHIKO , OHNO TOSHIYUKI , HIOKI FUMIAKI , SHINMOTO YASUHISA
Published: January 2005

Abstract: A two‐phase flow loop is a promising method for application to thermal management systems for large‐scale space platforms handling large amounts of energy. Boiling heat transfer reduces the size and weight of cold plates. The transportation of latent heat reduces the mass flow rate of working fluid and pump power. To develop compact heat exchangers for the removal of waste heat from electronic devices with high heat generation density, experiments on a method to increase the critical heat flux for a narrow heated channel between parallel heated and unheated plates were conducted. Fine grooves are machined on the heating surface in a transverse direction to the flow and liquid is supplied underneath flattened bubbles by the capillary pressure difference from auxiliary liquid channels separated by porous metal plates from the main heated channel. The critical heat flux values for the present heated channel structure are more than twice those for a flat surface at gap sizes 2 mm and 0.7 mm. The validity of the present structure with auxiliary liquid channels is confirmed by experiments in which the liquid supply to the grooves is interrupted. The increment in the critical heat flux compared to those for a flat surface takes a maximum value at a certain flow rate of liquid supply to the heated channel. The increment is expected to become larger when the length of the heated channel is increased and/or the gravity level is reduced.

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A Study of Subcooled Pool Boiling of Water: Contact Area of Boiling Bubbles with a Heating Surface During a Heating Process
Authors: SUZUKI KOICHI , TAKAHASHI SAIKA , OHTA HARUHIKO
Published: January 2005

Abstract:The contact area of bubbles with a transparent heating surface was optically measured during subcooled pool boiling of water on the ground. In the experiments, boiling bubbles were attached to the heating surface with a bubble holder and nearly reproduced the bubble behavior observed in low gravity. DC power was applied to the ITO heater and increased until the heater surface burned out. In quick heating, that is about 20 second until burnout and equal to the heating time during the low gravity period, the contact area was smaller than that for long time heating at the same heat flux. The experimental results suggest the reason why the critical heat flux in pool boiling is higher than the widely accepted predictions in microgravity. In a drop shaft experiment with constant heating, the contact area increased dramatically at the start of microgravity and became constant. Boiling bubbles coalesced and remained just over the heating surface.
Unsteady Near‐Critical Flows in Microgravity
Authors: POLEZHAEV V I , GORBUNOV A A , SOBOLEVA E B
Published: January 2005

Abstract: This paper presents analysis of the different time scales associated with unsteady fluid flow phenomena near the thermodynamical critical point and that are typical for experiments carried out in microgravity. A focus of the paper is modeling the initial stage of convection under low and zero gravity on the basis of the two‐dimensional Navier‐Stokes equations for a compressible gas with the Van der Waals state equation. We also consider a thermoacoustic problem on the basis of three‐dimensional linearized equations for an isentropic inviscid gas near the critical point in zero gravity. We compare the heat transfer due to unsteady convection and the piston effect in an enclosure with side heating in zero and low gravity with pure conductivity.

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Thermocapillary Migration of a Drop: An Exact Solution with Newtonian Interfacial Rheology and Stretching/Shrinkage of Interfacial Area Elements for Small Marangoni Numbers
Authors: BALASUBRAMANIAM R , SHANKAR SUBRAMANIAN R
Published: January 2005

Abstract: In this paper we analyze the effects of the following phenomena associated with the thermocapillary migration of a drop. The first is the influence of Newtonian surface rheology of the interface and the second is that of the energy changes associated with stretching and shrinkage of the interfacial area elements, when the drop is in motion. The former occurs because of dissipative processes in the interfacial region, such as when surfactant molecules are adsorbed at the interface in sufficient concentration. The interface is typically modeled in this instance by ascribing to it a surface viscosity. This is a different effect from that of interfacial tension gradients arising from surfactant concentration gradients. The stretching and shrinkage of interfacial area elements leads to changes in the internal energy of these elements that affects the transport of energy in the fluids adjoining the interface. When an element on the interface is stretched, its internal energy increases because of the increase in its area. This energy is supplied by the neighboring fluids that are cooled as a consequence. Conversely, when an element on the interface shrinks, the adjoining fluids are warmed. In the case of a moving drop, elements of interfacial area are stretched in the forward half of the drop, and are shrunk in the rear half. Consequently, the temperature variation on the surface of the drop and its migration speed are modified. The analysis of the motion of a drop including these effects was first performed by LeVan in 1981, in the limit when convective transport of momentum and energy are negligible. We extend the analysis of LeVan to include the convective transport of momentum by demonstrating that an exact solution of the momentum equation is obtained for an arbitrary value of the Reynolds number. This solution is then used to calculate the slightly deformed shape of the drop from a sphere.
Miscible, Porous Media Displacements with Density Stratification
Authors: RIAZ AMIR , MEIBURG ECKART
Published: January 2005

Abstract: High accuracy, three‐dimensional numerical simulations of miscible displacements with gravity override, in both homogeneous and heterogeneous porous media, are discussed for the quarter five‐spot configuration. The influence of viscous and gravitational effects on the overall displacement dynamics is described in terms of the vorticity variable. Density differences influence the flow primarily by establishing a narrow gravity layer, in which the effective Péclet number is enhanced due to the higher flow rate. Although this effect plays a dominant role in homogeneous flows, it is suppressed to some extent in heterogeneous displacements. This is a result of coupling between the viscous and permeability vorticity fields. When the viscous wavelength is much larger than the permeability wavelength, gravity override becomes more effective because coupling between the viscous and permeability vorticity fields is less pronounced. Buoyancy forces of a certain magnitude can lead to a pinch‐off of the gravity layer, thereby slowing it down.
Gravitational Effects on Structure Development in Quenched Complex Fluids
Authors: BADALASSI V E , CENICEROS H D , BANERJEE S
Published: January 2005

Abstract: When binary liquid mixtures are cooled rapidly from a homogeneous phase into a two‐phase system, domains of the two equilibrium phases form and grow (coarsen) with time. In the absence of an external forcing due to gravity or an imposed shear flow, a dynamic scaling regime emerges in which the domain morphology is statistically self‐similar at different times with a length‐scale that grows with time. In the presence of gravity, however, multiple length scales develop, with the system coarsening more rapidly in the direction of the force. The late‐time behavior of such a system is characterized in this study by the calculation of anisotropic growth laws. Gravitation effects significantly affect scaling laws, even with small density mismatch, and the growth mechanism has some similarities to the sedimentation process. However, very few numerical studies have been made of such effects; this is one of the first.
An Experimental Study of the Richtmyer‐Meshkov Instability in Microgravity
Authors: NIEDERHAUS CHARLES E. , JACOBS JEFFREY W.
Published: January 2005

Abstract: Richtmyer‐Meshkov (RM) instability occurs when a planar interface separating two fluids of different density is impulsively accelerated in the direction of its normal. It is one of the most fundamental fluid instabilities and is of importance to the fields of astrophysics and inertial confinement fusion. Because RM instability experiments are normally carried out in shock tubes, where the generation of a sharp, well‐controlled interface between gases is difficult, there is a scarcity of good experimental results. The experiments presented here use a novel technique that circumvents many of the experimental difficulties that have previously limited the study of RM instability in shock tubes. In these experiments, the instability is generated incompressibly, by bouncing a rectangular tank containing two liquids off of a fixed spring. These experiments, which utilize PLIF flow visualization, yield time‐motion image sequences of the nonlinear development and transition to turbulence of the instability that are of a quality unattainable in shock tube experiments. Measurements obtained from these images, therefore, provide benchmark data for the evaluation of nonlinear models for the late‐time growth of the instability. Because the run time in these experiments is limited, new experiments in the NASA Glenn 2.2 second drop tower, capable of achieving longer run times, are currently under way.
Manipulation of Fluid Objects with Acoustic Radiation Pressure
Authors: MARSTON PHILIP L. , THIESSEN DAVID B.
Published: January 2005

Abstract: Conditions are summarized for manipulating and stabilizing fluid objects based on the acoustic radiation pressure of standing waves. Examples include (but are not limited to) liquid drops, gas bubbles in liquids, and cylindrical liquid bridges. The emphasis is on situations where the characteristic wavelength of the acoustic field is large in comparison to the relevant dimension of the fluid object. Tables are presented for ease of comparing the signs of qualitatively different radiation force parameters for a variety of fluid objects.
Contrasting Electrostatic and Electromagnetic Levitation Experimental Results for Transformation Kinetics of Steel Alloys
Authors: MATSON DOUGLAS M. , FAIR DAVID J. , HYERS ROBERT W. , ROGERS JAN R.
Published: January 2005

Abstract: The delay between conversion of metastable ferrite to stable austenite during ternary Fe‐Cr‐Ni alloy double recalescence is seen to differ by over an order of magnitude for tests conducted using electrostatic and electromagnetic levitation. Several possible reasons for this deviation are proposed. Thermodynamic calculations on evaporation rates indicate that potential composition shifts during testing are minimized by limiting test time and thermal history. Simulation indicates that deviation would be limited to a factor of 1.5 under worst‐case conditions. Possible effects due to differences in sample size are also eliminated since the metastable array, where stable phase nucleation must occur, is significantly smaller than the sample. Differences in internal convection are seen to be the most probable reason for the observed deviation.

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Shape Relaxation of Liquid Drops in a Microgravity Environment
Authors: SADHAL S S , REDNIKOV A , OHSAKA K
Published: January 2005

Abstract: We investigated shape relaxation of liquid drops in a microgravity environment that was created by letting the drops fall freely. The drops were initially levitated in air by an acoustic/electrostatic hybrid levitator. The levitated drops were deformed due to the force balance among the levitating force, surface tension, and gravity. During the free fall, the deformed drops underwent shape relaxation driven by the surface tension to restore a spherical shape. The progress of the shape relaxation was characterized by measuring the aspect ratio as a function of time, and was compared to a simple linear relaxation model (in which only the fundamental mode was considered) for perfectly conductive drops. The results show that the model quite adequately describes the shape relaxation of uncharged/charged drops released from an acoustically levitated state. However, the model is less successful in describing the relaxation of drops that were levitated electrostatically before the free fall. This may be due to finite electrical conductivities of liquids, which somehow affects the initial stage of the shape relaxation process.
Property Measurements and Solidification Studies by Electrostatic Levitation
Authors: PARADIS PAUL‐FRANÇOIS , YU JIANDING , ISHIKAWA TAKEHIKO , YODA SHINICHI
Published: January 2005

Abstract: The National Space Development Agency of Japan has recently developed several electrostatic levitation furnaces and implemented new techniques and procedures for property measurement, solidification studies, and atomic structure research. In addition to the contamination‐free environment for undercooled and liquid metals and semiconductors, the newly developed facilities possess the unique capabilities of handling ceramics and high vapor pressure materials, reducing processing time, and imaging high luminosity samples. These are exemplified in this paper with the successful processing of BaTiO3. This allowed measurement of the density of high temperature solid, liquid, and undercooled phases. Furthermore, the material resulting from containerless solidification consisted of micrometer‐size particles and a glass‐like phase exhibiting a giant dielectric constant exceeding 100,000.
Ventless Pressure Control of Two‐Phase Propellant Tanks in Microgravity
Authors: KASSEMI MOHAMMAD , PANZARELLA CHARLES H.
Published: January 2005

Abstract: This work studies pressurization and pressure control of a large liquid hydrogen storage tank. A finite element model is developed that couples a lumped thermodynamic formulation for the vapor region with a complete solution of the Navier‐Stokes and energy equations for the flow and temperature fields in the liquid. Numerical results show that buoyancy effects are strong, even in microgravity, and can reposition a vapor bubble that is initially at the center of the tank to a region near the tank wall in a relatively short time. Long‐term tank pressurization with the vapor bubble at the tank wall shows that after an initial transient lasting about a week, the final rate of pressure increase agrees with a purely thermodynamic analysis of the entire tank. However, the final pressure levels are quite different from thermodynamic predictions. Numerical results also show that there is significant thermal stratification in the liquid due to the effects of natural convection. A subcooled jet is used to provide simultaneous cooling and mixing in order to bring the tank pressure back down to its initial value. Three different jet speeds are examined. Although the lowest jet speed is ineffective at controlling the pressure because of insufficient penetration into the liquid region, the highest jet speed is shown to be quite effective at disrupting thermal stratification and reducing the tank pressure in reasonable time.

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Design and Preparation of a Particle Dynamics Space Flight Experiment, SHIVA
Authors: TROLINGER JAMES D. , L'ESPERANCE DREW , RANGEL ROGER H. , COIMBRA CARLOS F.M. , WITHEROW WILLIAM K.
Published: January 2005

Abstract: This paper describes the flight experiment, supporting ground science, and the design rationale for a project on spaceflight holography investigation in a virtual apparatus (SHIVA). SHIVA is a fundamental study of particle dynamics in fluids in microgravity. Gravitation effects and steady Stokes drag often dominate the equations of motion of a particle in a fluid and consequently microgravity provides an ideal environment in which to study the other forces, such as the pressure and viscous drag and especially the Basset history force. We have developed diagnostic recording methods using holography to save all of the particle field optical characteristics, essentially allowing the experiment to be transferred from space back to Earth in what we call the “virtual apparatus” for microgravity experiments on Earth. We can quantify precisely the three‐dimensional motion of sets of particles, allowing us to test and apply new analytic solutions developed by members of the team. In addition to employing microgravity to augment the fundamental study of these forces, the resulting data will allow us to quantify and understand the ISS environment with great accuracy. This paper shows how we used both experiment and theory to identify and resolve critical issues and to produce an optimal experimental design that exploits microgravity for the study. We examined the response of particles of specific gravity from 0.1 to 20, with radii from 0.2 to 2 mm, to fluid oscillation at frequencies up to 80 Hz with amplitudes up to 200 microns. To observe some of the interesting effects predicted by the new solutions requires the precise location of the position of a particle in three dimensions. To this end we have developed digital holography algorithms that enable particle position location to a small fraction of a pixel in a CCD array. The spaceflight system will record holograms both on film and electronically. The electronic holograms can be downlinked providing real‐time data, essentially acting like a remote window into the ISS experimental chamber. Ground experiments have provided input to a flight system design that can meet the requirements for a successful experiment on ISS. Moreover the ground experiments have provided a definitive, quantitative observation of the Basset history force over a wide range of conditions. Results of the ground experiments, the flight experiment design, preliminary flight hardware design, and data analysis procedures are reported.
A novel anaesthetic regimen for surgical procedures in guineapigs
Authors: Jacobson C.
Published: January 2005

A combination of tiletamine/zolazepam, xylazine and butorphanol provides deep surgical, long-duration anaesthesia in guineapigs with a smooth induction and recovery period. The described dosages mainly affect the respiratory functions and blood gas parameters, with a minor-to-moderate effect on the cardiovascular system.
Improved Constraints on Sedimentary Environments of Palygorskite Deposits of the Hawthorne Formation, Southern Georgia, from a Detailed Study of a Core
Authors: Krekeler Mark P. S.
Published: January 2005

The sedimentology and mineralogy of a 2.5 m core from a palygorskite deposit of the Miocene Hawthorne Formation, southern Georgia is described. The lithology involves laminated clay-rich sediment composed of ∼90% clay and 10% sand, with six clay-pebble layers present. Sand to pebble-size clasts of phosphate material are common throughout the core. The sand laminations are probably flood-related and the clay-pebble layers are storm deposits, with the pebbles being derived locally from subaerial environments. Phosphate clasts are reworked bone material.

The sands are quartz-rich and are subarkosic in composition with average quartz counts of 86.50% and average total feldspar counts of 11.50%. Heavy minerals observed include orthopyroxene, clinopyroxene, amphibole, zircon, rutile, garnet, tourmaline, kyanite, muscovite, biotite, spinels and opaques. Palygorskite fibers dominate the clay-size fraction of the samples and comprise ∼80–90% of sample material with smectite comprising the remainder. Hydroxylapatite comprises ∼3% of sediment volume and occurs as individual euhedral hexagonal crystals and as clusters of crystals.

Investigation of this core suggests that the palygorskite deposit represents a dynamic system with regular flooding and storm deposition being common. Mineral composition of sands may be useful for stratigraphic correlation of palygorskite deposits in the Apalachicola Embayment. This study supports the general environmental interpretations of previous workers for the palygorskite deposits of southern Georgia, but provides greater detail.
Authigenic Ti-Bearing Crystals in a Precambrian Clay from Buenos Aires Province, Argentina
Authors: Alló Wanda
Published: January 2005

The Precambrian Villa Mónica Formation clay was analyzed using petrographic and scanning electron microscopy, X-ray diffraction and chemical analysis, with the aim of characterizing the Ti-bearing phases present and determining their possible origin and/or source. Two Ti-bearing minerals were found to be present, rutile and anatase. The crystals are needles between 5 and 15 µm in size, with no evidence of abrasion or corrosion. They are commonly found in association with the (001) faces of illite flakes or in the pores between the flakes. Their disposition is similar in the three quarries studied. No zonation or differential settling due to differences in specific gravity was observed. In addition, chemical analyses indicated a positive correlation between TiO2 and K2O suggesting that both oxides behave similarly after the deposition of the sediment. The TiO2 content in the bulk fraction ranges from 0.8 to 1.98 wt.%, values that are similar to those exhibited in other clay deposits from different ages and geneses.

All observations are consistent with an in situ origin of these Ti-bearing phases during post-depositional processes that included recrystallization of existing minerals and crystallization of new phases. The original detrital minerals such as biotite, ilmenite as well as detrital illite, were the primary sources of the TiO2 and of the Fe oxides that coat the clay. Understanding the origin and the reaction mechanisms involved during the post-depositional alteration of the Villa Mónica Formation suggests that the Ti-bearing phases in different sediment types were formed by similar mechanisms involving redox processes at low to medium temperatures, even in Precambrian sediments where the presence of rutile could lead to an incorrect assumption of high temperatures involved.
Discriminant Analysis of Clay Mineral Compositions
Authors: Varadachari Chandrika , Mukherjee Gargi
Published: January 2005

Compositional data for 464 clay minerals (2:1 type) were analyzed by statistical techniques. The objective was to understand the similarities and differences between the groups and subgroups and to evaluate statistically clay mineral classification in terms of chemical parameters. The statistical properties of the distributions of total layer charge (TLC), K, VIAl, VIMg, octahedral charge (OC) and tetrahedral charge (TC) were initially evaluated. Critical-difference (P = 1%) comparisons of individual characteristics show that all the clay micas (illite, glauconite and celadonite) differ significantly from all the smectites (montmorillonite, beidellite, nontronite and saponite) only in their TLC and K levels; they cannot be distinguished by their VIAl, VIMg, TC or OC values which reveal no significant differences between several minerals.

Linear discriminant analysis using equal prior was therefore performed to analyze the combined effect of all the chemical parameters. Using six parameters [TLC, K, VIAl, VIMg, TC and OC], eight minerals groups could be derived, corresponding to the three clay micas, four smectites (mentioned above) and vermiculite. The fit between predicted and experimental values was 88.1%. Discriminant analysis using two parameters (TLC and K) resulted in classification into three broad groups corresponding to the clay micas, smectites and vermiculites (87.7% fit). Further analysis using the remaining four parameters resulted in subgroup-level classification with an 85–95% fit between predicted and experimental results. The three analyses yielded D2 Mahalanobis distances, which quantify chemical similarities and differences between the broad groups, within members of a subgroup and also between the subgroups. Classification functions derived here can be used as an aid for classification of 2:1 minerals.
Cesium Sorption to Illite as Affected by Oxalate
Authors: Wendling Laura A. , Harsh James B. , Palmer Carl D. , Hamilton Melinda A. , Flury Markus
Published: January 2005

Cesium uptake by plants depends on adsorption/desorption reactions in the soil, as well as root uptake processes controlled by the plant. In this study, sorption and desorption of Cs+ on reference illite (IMt-1) was investigated in the presence of oxalate to gain understanding of mechanisms by which plant root exudates may influence Cs+ bioavailability in micaceous soils. Cesium sorption on illite decreased significantly as oxalate concentration increased from 0.4 to 2 mM. Cesium desorption from illite increased significantly with increasing oxalate concentration. Desorption of Cs+ by exchange with Na+, Ca2+ and Mg2+ was significantly enhanced in the presence of oxalate as selectivity for Cs+ decreased with respect to these ions in the presence of oxalate. On the other hand, oxalate had little effect on the Cs+/K+ selectivity coefficient. This suggests that oxalate treatments increase the relative proportion of exchange sites that are not highly selective for Cs+ and K+; e.g. ‘planar’ sites. The results indicate that oxalate plays an important role in Cs+ binding on illite and, therefore, plant rhizosphere chemistry is likely to alter Cs+ bioavailability in micaceous soils.
The effects of grades on course enjoyment: Did you get the grade you wanted?
Authors: Remedios Richard , Lieberman David A. , Benton Tim G.
Published: January 2005

Background. Students tend to rate university courses more positively if they do well. Greenwald and Gillmore (1997a) suggested that it is not students’ absolute grades that are important but rather how these grades compare to their expectations. However, this hypothesis is difficult to evaluate because few studies have measured grade expectations at the beginning of courses. Aim. By measuring students’ grade expectations and enjoyment at several stages during a course, we hoped to evaluate the extent to which expectations modulate the impact of grades on course enjoyment. Sample. Participants were 242 students in a university course in psychology. Method. Students were asked what grades they expected, and how much they were enjoying the course, at four stages. The effect of grades and grade expectations on enjoyment were analysed using restricted maximum likelihood (REML) and regression analyses. Results. The best predictor of course enjoyment varied somewhat at different stages, but in general it was the extent to which students’ grades surpassed their expectations. Students’ expectations at the beginning of the course proved particularly influential. Conclusions. Grade expectations do influence how students react to course grades, but the prominent role of pre‐course expectations suggests that it may be important to distinguish between grade aspirations and grade expectations. It appears to be students’ aspirations ‐ the grades they hope to achieve ‐ that most strongly shape their emotional reactions, rather than the more realistic expectations they may form later in a course.
Item‐level and subscale‐level factoring of Biggs’ Learning Process Questionnaire (LPQ) in a mainland Chinese sample
Authors: Sachs John , Gao Lingbiao
Published: January 2005

Background. The learning process questionnaire (LPQ) has been the source of intensive cross‐cultural study. However, an item‐level factor analysis of all the LPQ items simultaneously has never been reported. Rather, items within each subscale have been factor analysed to establish subscale unidimensionality and justify the use of composite subscale scores. Aims. It was of major interest to see if the six logically constructed items groups of the LPQ would be supported by empirical evidence. Additionally, it was of interest to compare the consistency of the reliability and correlational structure of the LPQ subscales in our study with those of previous cross‐cultural studies. Methods. Confirmatory factor analysis was used to fit the six‐factor item level model and to fit five representative subscale level factor models. Sample. A total of 1070 students between the ages of 15 to 18 years was drawn from a representative selection of 29 classes from within 15 secondary schools in Guangzhou, China. Males and females were almost equally represented. Results. The six‐factor item level model of the LPQ seemed to fit reasonably well, thus supporting the six dimensional structure of the LPQ and justifying the use of composite subscale scores for each LPQ dimension. However, the reliability of many of these subscales was low. Furthermore, only two subscale‐level factor models showed marginally acceptable fit. Substantive considerations supported an oblique three‐factor model. Conclusions. Because the LPQ subscales often show low internal consistency reliability, experimental and correlational studies that have used these subscales as dependent measures have been disappointing. It is suggested that some LPQ items should be revised and other items added to improve the inventory's overall psychometric properties.
Exposing Silence as Cultural Censorship: A Brazilian Case
Authors: Sheriff Robin E.
Published: January 2005

In this article I assert that in focusing on salient discourses, contested cultural domains, and public forms of conflict and power, cultural and linguistic anthropologists, and other social scientists, have overlooked the significance of communal forms of silence in shaping the social and political landscape. I argue that such customary silences constitute "cultural censorship," which, unlike state‐sponsored censorship, is practiced in the absence of explicit coercion or enforcement. Although practiced by different and opposed groups, cultural censorship tends to be constituted through, and circumscribed by. the political interests of dominant groups. In this article, which is based on ethnographic research in Rio de Janeiro. I analyze a case of cultural censorship by examining the customary silence surrounding the subject of racism in Brazil. By emphasizing the phenomenology of cultural censorship among poor Brazilians of African descent. 1 argue that silence must not be conflated with, and does not preclude the existence of. non‐hegemonic consciousness, [silence, cultural censorship, consciousness, Brazil, racism]
First Peoples, First Contacts: Tangible Records
Authors: Oberholtzer Cath
Published: January 2005

First Peoples, First Contacts: Tangible Records. Chase Manhattan Gallery of North America and First Peoples, First Contacts, British Museum, London, permanent installation.

First Peoples, First Contacts: Native Peoples of North America. J. C. H. King. Cambridge, MA: Harvard University Press, 1999.288 pp.
Sigmund Freud: Conflict and Culture
Authors: Ackerman Raqlel
Published: January 2005

Sigmund Freud: Conflict and Culture. The Library of Congress, Washington, D.C., October 15, 1998‐January 16, 1999; The Jewish Museum, New York, New York, April 18‐September 9. 1999, review venue; Freud Museum, Vienna, Austria. October 21, 1999‐February 6. 2000; Skirball Cultural Center, Los Angeles. California. April 4‐July 25, 2000.

Freud: Conflict and Culture. Essays on His Life, Work and Legacy. Michael S. Roth. ed. New York: Alfred Knopf, 1998. 273 pp.
Dhiava: The Autumn Journey.
Authors: Allen Peter S.
Published: January 2005

Dhiava: The Autumn Journey. 1997 (U.S. release date: 1999). 50 minutes, color. film by David Hope and Tim Salmon. For more information, please contact Documentary Educational Resources. 101 Morse Street. Watertown. MA 02472, (617) 926‐ 0491, (617) 926‐9519 (fax).