bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐Temperature Active Oxidation of Chemically Vapor‐Deposited Silicon Carbide in CO─CO2 Atmosphere
Authors: Narushima Takayuki , Goto Takashi , Yokoyama Yoshio , Iguchi Yasutaka , Hirai Toshio
Published: March 2005

Active oxidation behavior of CVD‐SiC in CO─CO2 atmospheres was investigated using a thermogravimetric technique in the temperature range between 1823 and 1923 K. The gas pressure ratio, PCO2/PCO, was controlled between 10−4 and 10−1 at 0.1 MPa. Active oxidation rates (mass loss rates) showed maxima at a certain value of PCO2/PCO, (PCO2/PCO)*, In a PCO2/PCO region lower than the (PCO2/PCO)* a carbon layer was formed on the SiC surface. In a PCO2/PCO region higher than the (PCO2/PCO)*, silica particles or a porous silica layer was observed on the SiC surface.
Fracto‐emission during Fracture of Engineering Ceramics
Authors: Enomoto Yuji , Chaudhri M. Munawar
Published: March 2005

An experimental study of the emission of fracto‐electrons from engineering ceramics, such as Al2O3, ZrO2, Al2O3/ZrO2, and Si3N4, has been made under ambient atmospheric conditions when they were fractured with an indenter mounted on the arm of a Charpy impact machine or by a power press machine. In these experiments, the indenter, made of a hard electro‐conductive material, acted as an electrode to collect the emitted electrons; the collected electrons were fed into a high‐sensitivity charge amplifier. The results obtained showed that, when the test specimen fractured, fracto‐electrons were emitted. This was confirmed by the simultaneous appearance of the electrical and acoustical signals. The total charge collected varied in the range of 10−11–10−9 C, depending on the fracture mode, fracture load, and the nature of the gaseous environment. The fracture surfaces of the specimens were found to be electrified, reaching potentials of the order of a few hundred volts. We believe that the origin of the fracto‐emission of electrons is the separation of the charges on the fracturing surfaces, which leads to the formation of an electric field and the liberation of exoelectrons; these electrons are of sufficiently high energies to cause the ionization of the ambient gaseous atoms/molecules.
Preparation of Composite Particles by Pulsed Nd‐YAG Laser Decomposition of [(CH3)2N]4Ti to TiN‐Coat TiO2, Al2O3, or Si3N4 Powders
Authors: Narula Chaitanya K. , Maricq M. Matti , Demczyk Brian G. , Salmeen Irving T. , Weber Willes H.
Published: March 2005

Irradiation of Ti[N(CH3)2]4 by the 1.064‐μm line of a pulsed Nd: YAG laser in the presence of TiO2, Al2O3, or Si3N4 particles has been found to form amorphous deposits on the oxide particles. The resulting materials can be processed into TiN/TiO2, TiN/Al2O3, or TiN/Si3N4 composites with the TiN component on the surface of the particles. The powders have been characterized by Raman spectroscopy and X‐ray powder diffraction studies. The surface analysis of the composites by X‐ray photoelectron spectroscopy and high‐resolution electron microscopy is presented.
A New SiC‐Whisker‐Reinforced Lithium Aluminosilicate Composite
Authors: Xue Liang A. , Chen I‐Wei
Published: March 2005

The glass‐ceramic matrix of the well‐known lithium aluminosilicate (LAS)/SiC composite is usually formulated near the spodumene composition. We report here a new composition which is rich in alumina (78 wt%) and lean in silica (21 wt%) and lithia (1 wt%). This formulation offers a new option of converting the glass‐ceramic matrix to a mullite/alumina matrix upon annealing above 1400°C, and hence better creep resistance and other high‐temperature mechanical properties. Using a transient‐phase processing method that we developed previously for the superplastic forming of mullite, we are able to hot‐press a composite containing 30 vol% SiC whiskers at ∼1350°C to achieve full density. Flexural strength measurements up to 1400°C have confirmed the improved high‐temperature strength and creep resistance over conventional LAS. The fracture toughness is also higher than that of LAS. The results suggest that the new composition may be chosen as a better candidate matrix for SiC‐fiber‐reinforced composites.
Thermodynamic Activities in B2O3‐SiO2 Melts at 1475 K
Authors: Boike Martin , Hilpert Klaus , Müller Franz
Published: March 2005

Eight glass samples in the B2O3‐SiO2 system with compositions from 20 to 90 mol% B2O3 were prepared. The equilibrium vaporization was studied by Knudsen effusion mass spectrometry at temperatures between 1450 and 1500 K. B2O3 (g) was the most abundant boron‐containing species in the vapor; no silicon‐containing gaseous species were detected. Thermodynamic activities of B2O3 in the liquid were determined at 1475 K. Thermodynamic activities of SiO2 and integral excess Gibbs energies were estimated from the thermodynamic activities of B2O3. The thermodynamic data support the results obtained by other methods indicating the existance of a miscibility gap in the metastable liquid.
Ambient and High‐Temperature Stable Fracture Tests in Ceramics: Applications to Yttria‐Partially‐Stabilized Zirconia
Authors: Pastor Jose Ygnacio , Planas Jaime , Elices Manuel
Published: March 2005

A new technique that provides stable fracture tests in brittle ceramic materials at room and at high temperature is presented. This technique uses the crack mouth opening displacement signal from a laser extensometer to feed the servo control of a hydraulic testing machine. In this way it is possible to obtain—in addition to the fracture toughness—the fracture energy and the R‐curve, in a single test.
Electrically Conducting PbyOx–SiO2 Glass Films Deposited by Reactive Radio‐Frequency Magnetron Sputtering
Authors: Mea Gianantonio Della , Rigato Valentino , Maschio Roberto Dal , Sighel Corrado , Colombo Paolo
Published: March 2005

Lead silicate glass films were deposited on sapphire substrates in different plasmas (100% Ar; 20% H2+ 80% Ar; 5% O2+ 95% Ar) by reactive radio‐frequency magnetron sputtering. The stoichiometry of the films, determined by Rutherford backscattering spectroscopy, changed with the deposition conditions. X‐ray diffractometry analysis showed the presence of metallic Pb in the samples sputtered in H2‐containing plasma. The room‐temperature sheet resistance of the films ranged from >1016Ω/□ (O2‐containing atmosphere) to about 103Ω/□ (H2‐containing atmosphere).
Preparation and Properties of Low‐Calcium–Content Superconductive Thin Films in Bismuth Systems
Authors: Tsukamoto Keizou , Shimojima Hiromasa , Ishii Mamoru , Enomoto Naoya , Yamagishi Chitake
Published: March 2005

Superconductive, polycrystalline thin films from Bi systems with low Ca content in relation to the high‐Tc phase and with various Bi(Pb) contents were obtained by two‐step annealing of the deposited amorphous films prepared by rf magnetron sputtering. The obtained films, A, B, and C, exhibited a high Tc (Tc > 100 K) for a wide range of secondary annealing temperatures. The critical current densities of these films at 77.3 K in zero magnetic field were sensitive to the secondary annealing temperature. The highest critical current densities of the films were 27000, 3900, and 5500 A/cm2 for films A, B, and C, respectively. Film B exhibited large decreases in critical current density under an applied magnetic field. The grain boundaries of this film, which were composed of PbO, CuO, and Bi2O3, apparently acted as weak links in the superconductor materials.
Wettability and Interfacial Reaction between Molten lron and Zirconia Substrates
Authors: Nakashima Kunihiko , Takihira Kenji , Miyazaki Takashi , Mori Katsumi
Published: March 2005

The surface tension of, and the contact angle formed by, molten iron on three types of commercial zirconia substrates containing 8 mol% Y2O3, 9 mol% MgO, or 11 mol% CaO were measured over a wide range of oxygen concentration in the molten iron by the sessile drop method. The solidified metal–substrate interface was examined in an SEM equipped with an EPMA. The surface tension of molten iron decreased with increasing oxygen concentration. The contact angle of molten iron increased rapidly with increasing oxygen concentration and reached a local maximum value at an oxgyen concentration of ∼100 ppm, and then decreased with increasing oxygen concentration. At lower oxygen concentration, dissociation of ZrO2 was observed. For the ZrO2–9 mol% MgO substrate, segregation of MgO to the interface was observed. For the ZrO2–11 mol% CaO substrate, segregation of CaO and the precipitation of small ZrO2 particles in the segregation layer of CaO were observed at the interface. Conversely, at higher oxygen concentration, penetration of molten iron into the grain boundaries was observed in all types of zirconia substrates.
Phenomenological Thermodynamic Treatment of Elastically Stressed Ionic Crystals
Authors: Johnson William C. , Schmalzried Hermann
Published: March 2005

A phenomenological thermodynamic treatment of multicomponent, elastically stressed ionic crystals is presented and the conditions for thermodynamic equilibrium derived using a Gibbsian variational approach. By assuming that the electrostatic and electronic contributions to the internal energy density are determined by the local electric displacement and the distribution of unassociated charge between the valence and conduction bands, respectively, (metallic) conductors, semiconductors, and insulators can be treated. This approach is compatible with thermodynamic treatments of stressed metallic systems and the structure‐element description of ionic crystals.
Effect of Silica on the Thermal Conductivity of Aluminum Nitride
Authors: de Baranda Pedro Sainz , Knudsen Arne K. , Ruh Edwin
Published: March 2005

The effect of SiO2 on the thermal conductivity of aluminum nitride pressureless sintered with 3 wt% Y2O3 as a sintering aid was investigated. SiO2 additions greatly decreased the thermal conductivity of the sintered parts from values of around 160 W/m·K on undoped samples to about 25 W/m·K with 5 wt% SiO2 added to the green body composition. Microstructural studies, combined with the temperature dependence of the thermal conductivity and lattice parameter measurements, indicated that defect phonon scattering was the mechanism responsible for the decrease in thermal conductivity. SiO2 can be incorporated in limited solid solution into the AIN lattice, generating AI vacancies for charge compensation in a process not unlike the solution of oxygen in AIN. The mass difference introduced by the vacancies is the main phonon scattering defect. Beyond a concentration threshold of 2%, the SiO2‐induced defects cluster to form SiAION polytypoids derived from the basic 2H AIN structure with stacking sequences that depend on the SiO2 levels in the sample.
Preparation and Phase Separation Behavior of (Co,Fe)3O4 Films
Authors: Hirano Shin‐ichi , Yogo Toshinobu , Kikuta Ko‐ichi , Asai Emi , Sugiyama Kiyoshi , Yamamoto Hiroshi
Published: March 2005

(Co,Fe)3O4 films were synthesized by the sol–gel method through metalorganic compounds. The (Co,Fe)3O4 films (Co:Fe = 2:1) showed the characteristic behavior of the spinodal decomposition by heat treatments within the miscibility gap. The coercive force of the spinodally decomposed films increased from 0.9 kOe for a solid solution to 2.0 kOe for films that underwent the spinodal decomposition. The nonmagnetic phase (rich in Co) formed by the spinodal decomposition contributes to the pinning of the movement of magnetic domain walls. On the other hand, the (Co,Fe)3O4 films (Co:Fe = 1:1) showed the typical feature of binodal decomposition during heat treatment within the miscibility gap. The binodally decomposed films showed a slight increase in the coercive force depending upon the evolution of the magnetic region.
Bulk Modulus and Young's Modulus of Nanocrystalline γ‐Alumina
Authors: Gallas Marcia R. , Piermarini Gasper J.
Published: March 2005

Compression measurements were performed for the first time on nanocrystalline γ‐alumina utilizing a diamond anvil cell (DAC) and the energy dispersive X‐ray diffraction method. The cubic unit cell (a= 0.7924 nm) for γ‐alumina was found to have a volume compression of about 2.4% over the pressure range from ambient to 3.8 GPa at room temperature under both hydrostatic and nonhydrostatic conditions. Using the first‐order Bridgman equation and the Birch equation of state, the isothermal bulk modulus (B0) was determined to be 162 ± 14 GPa and Young's modulus (E) was estimated to be 253 ± 22 GPa assuming a Poisson's ratio for γ‐alumina of 0.24 ± 0.2.
Crystal Structures of the High‐Temperature Forms of Ln2Si2O7 (Ln = La, Ce, Pr, Nd, Sm) Revisited
Authors: Tas A. Cuneyt , Akinc Mufit
Published: March 2005

The crystal structures of the high‐temperature forms of light lanthanide pyrosilicates (disilicates), i.e., (La‐to‐Sm)2Si2O7, have been studied with powder X‐ray diffraction on the quenched samples. These compounds have monoclinic structures with the space group P21/n rather than orthorhombic structures. In the research of the last two decades, the smallness of the monoclinic angles (90.1°–91°) has possibly obscured the revelation of the true structural nature of these compounds. New XRD patterns are suggested for the studied lanthanide pyrosilicates exhibiting the monoclinic characteristics of the unit cells.
At‐Temperature Neutron Diffraction Investigation of the Aging Process in Magnesia‐Partially‐Stabilized Zirconia
Authors: Argyriou Dimitri N. , Howard Christopher J. , Smith Ronald I.
Published: March 2005

A time‐resolved neutron powder diffraction technique has been used to follow the changes occurring during the aging of magnesia‐partially‐stabilized zirconia at 1100°C. Through quantitative phase analyses it has been possible to follow the development with aging time of tetragonal zirconia and of the δ‐phase (Mg2Zr5O12, related to cubic, but with ordered anion vacancies), both at the expense of cubic zirconia. Changes in lattice parameters have been attributed to the expulsion of MgO stabilizer from the tetragonal zirconia precipitates as the aging proceeds. The broadening of peaks in the neutron diffraction pattern suggests there is considerable strain in the tetragonal precipitates in the c‐direction, which is the short dimension in these lenticular precipitates. On cooling, there is some transformation of tetragonal zirconia to the monoclinic and orthorhombic phases.
Compositional Dependence of Absorption Spectra of Ti3+ in Silicate, Borate, and Phosphate Glasses
Authors: Moringa Kenji , Yoshida Hideki , Takebe Hiromichi
Published: March 2005

Absorption spectra of Ti3+ were measured for silicate, borate, and phosphate glasses doped with 0.5 mol% Ti2O3.The absorption coefficient at the peak wavelength of the 2T2→2E transition of Ti3+ is used as a parameter showing the relative content of Ti3+ions in glass samples. The effect of glass composition on Ti3+/Ti4+ redox was studied. For multicomponent glasses, a basicity parameter calculated from glass composition is proposed in terms of coulomb force between the cation and the oxygen ion. The value of the absorption coefficient depends on basicity in silicate and borate glasses; however, it is independent of composition in phosphate glasses.
Tensile Creep in an in Situ Reinforced Silicon Nitride
Authors: Gasdaska Charles J.
Published: March 2005

The tensile creep of an in situ reinforced silicon nitride is described in terms of the rheological behavior of the thin intergranular film present in this liquid‐phase sintered silicon nitride. The high stress exponents and apparent activation energies (at constant stress) can be explained assuming non‐Newtonian flow behavior of the film during grain boundary sliding. Time‐to‐failure is related to the minimum creep rate, even for samples which fail by slow crack growth. In addition, the primary creep region and the relaxation effects observed on unloading are described in terms of grain boundary sliding modified by the presence of a grain boundary phase with a lower elastic modulus than silicon nitride.
Compositional Effect on the Liquid‐Phase Formation in Lead Iron Tungstate Ferroelectric Ceramics
Authors: Lu Chung‐Hsin
Published: March 2005

The iron content in Pb (Fe2/3W1/3) O3 was demonstrated in this study to substantially affect the formation of a liquid phase during the heating process. This liquid phase was generated in iron‐deficient specimens at a temperature around 870°C. However, no liquid phase could be formed in specimens with a stoichiometric or excess amount of iron. A slow cooling treament induced the liquid phase to migrate from the interior toward specimen surfaces and formulate a platelike phase. Formation of the liquid phase is attributed to the reaction of Pb2WO5 with residual iron species. The chemical gradient which occurred as a result of the temperature difference between the interior and the surface during slow cooling, as well as the capillary force in the narrowed pore channels between densified grains, are considered to be the driving forces for the migration of the liquid phase.
Transition of Compensating Defect Mode in Niobium‐Doped Barium Titanate
Authors: Wu Tai‐Bor , Lin Jiu‐Nun
Published: March 2005

The influence of Nb‐doping from 1.0 to 8.0 at.% on grain size, ferroelectric phase transition, lattice strain, and electrical properties of BaTiO3 Cerumics has been studied. A change in the Nb‐doping effect was observed at compositions around 3.5–4.5 at.% Nb. The impedance behavior revealed that specimens of low Nb‐doping had an activation energy of 1.85 eV for carrier conduction either in bulk or at grain boundaries, but specimens having a high Nb‐doping content showed an energy of 1.30 eV in bulk and 1.85 eV at grain boundaries. The capacitance–voltage relation also disclosed different influences of Nb‐doping on the potential barrier height at grain boundaries. The above results are explained by the transition of a compensating defect mode from pure barium vacancies to a combination of titanium vacancies in grain interiors and barium vacancies at grain boundaries as the Nb‐doping content in BaTiO3 is increased.
A Die Pressing Test for the Estimation of Agglomerate Strength
Authors: Song Jin‐Hua , Evans Julian R. G.
Published: March 2005

A die pressing test was developed for quick and inexpensive estimation of the agglomerate strength of ceramic powders. The critical nominal pressure (pc) at which contact areas between agglomerates start to increase rapidly was found from the relationship between change in sample height and applied pressure in uniaxial single‐ended die pressing. A quantitative microscopic method was used for measuring the area fraction (Ψ) of agglomerates which transmits the force through the assembly. A die pressing agglomerate strength, σd, is defined as σd= 0.7 pc/Ψ. This strength was compared with the agglomerate tensile strength obtained from single agglomerate diametral compression tests and found to be 50% higher than the latter because of multipoint loading. A suggested guideline is that the mean agglomerate tensile strength is approximately 52% of pc determined in a die pressing test for spherical agglomerates. In addition to agglomerate tensile strength, the mean agglomerate size, the interior macropore structure of agglomerates, as well as the packing efficiencies between and inside agglomerates can be estimated by the procedure.
Influence of Interparticle Forces on the Rheological Behavior of Pressure‐Consolidated Alumina Particle Slurries
Authors: Vdamakanni Bhaskar V. , Lange Fred F. , Zok Frank W. , Pearson Dale S.
Published: March 2005

The stress relaxation behavior of alumina powder compacts, consolidated from aqueous slurries by pressure filtration, is reported. The interparticle forces were controlled prior to consolidation by changing the pH from 3 to 9 and by adding different amounts of salt (0.1 to 2.0M NH4Cl) to slurries maintained at pH 4. Disk‐shaped bodies were rapidly compiessed to an axial strain of 2%, and the resulting stress relaxation data were monitored as a function of time. For bodies formed from dispersed slurries (pH ≤ 4 without added salt), the stress relaxation behavior consisted of an irreproducible mixture of plastic and elastic response. The initial stress and the stress retained afterlong relaxation periods were highest for bodies formed with flocced slurries (pH 9). For bodies formed with coagulated slurries (pH 4 with added salt), the initial stress increased with the addition of 0.1 to 0.5M salt, but the bodies behaved plastically, with more than 90% of the initial stress relaxing within a short period. These results are consistent with a shortrange, repulsive interparticle force that lowers the attractive force between particles. They also suggest that interparticle forces in consolidated bodies can be controlled in a way that should prove useful in preventing damage that occurs during processing and reshaping Operations.
X‐ray Diffraction Analysis of the Pyrolytic Conversion of Perhydropolysilazane into Silicon Nitride
Authors: Blanchard Cheryl R. , Schwab Stuart T.
Published: March 2005

A detailed investigation using X‐ray diffraction and other supportive techniques was performed on a preceramic polysilazane to study its pyrolytic conversion to silicon nitride (Si3N4). Analytical techniques were developed to determine the volumetric degree of crystallinity with respect to pyrolysis temperature. Quantitative data for crystallite size, phase composition, and degree of crystallinity versus pyrolysis temperature and atmosphere (nitrogen and ammonia) are presented. Pyrolytic products produced under nitrogen and ammonia atmospheres consist of microcrystals of silicon, α‐Si3N4, and β‐Si3N4. Under both atmospheres, a majority of the char is crystalline at ≅1270°C, and the entire char is crystallized at 1400°C. Pyrolysis under an ammonia atmosphere produces nearly stoichiometric Si3N4, while pyrolysis under nitrogen produces silicon‐rich material.
Alumina/Aluminum Composites Formed by the Directed Oxidation of Aluminum Using Sodium Hydroxide as a Surface Dopant
Authors: Xiao Ping , Derby Brian
Published: March 2005

Al2O3/Al composites have been formed by the directed oxidation of Al using NaOH as a surface dopant. Oxidation kinetics were monitored by thermogravimetric analysis. Product microstructures were examined using optical microscopy and scanning electron microscopy coupled with microanalysis using energy and wavelength dispersive spectroscopy. NaOH‐driven directed oxidation of Al occurs in the temperature range of 850°–1200°C, and the resulting microstructure varies with different doping levels. The growth product is seen to nucleate and grow not only on the top surface of the parent Al but also along the crucible wall and even on the external surface of the crucible. The Al channel size in the product is determined by the initial surface dopant level.
Pore Sizes and Filtration Rates from Two Alumina Slips
Authors: Smith Peter A. , Kerch Helen , Krueger Susan , Long Gabrielle G. , Keller Joseph , Haber Richard A.
Published: March 2005

The relationship between filtration rate and the resultant green body microstructure was examined for aqueous alumina slips cast at two different deflocculation states. The volume loading of both slips was 40%. Slip viscosities of 500 and 60 mPa·s were produced by different tetrasodium pyrophosphate additions. The filtration rate of these slips varied by a factor of 2; however, mercury porosimetry results showed the same average pore size for both samples. Single and multiple small‐angle neutron scattering results showed the specimen cast with the higher‐viscosity slip to possess a bimodal pore size distribution. The body cast with the low‐viscosity slip showed unimodal porosity and, consequently, the filtration is attributed to the toroidal region between the packed particles. These results showed that mercury porosimetry does not provide a pore size that predicts filtration behavior of slips with different degrees of dispersion.
Controlling Crystallinity during Processing of Nanocrystalline Titania
Authors: Hague Douglas C. , Mayo Merrilea J.
Published: March 2005

The present study shows that an extremely high water: alkoxide ratio during the hydrolysis of titanium isopropoxide results in a partially crystalline precipitate (5‐nm anatase crystallites); however, when these crystallites are rinsed with ethanol, the precipitate becomes amorphous. The degree of crystallinity of the precipitate determines its subsequent thermal decomposition characteristics and, ultimately, the crystallite size of the calcined powder.
Analysis of Fiber Frictional Sliding in Fiber Bundle Pushout Test
Authors: Zhou Li‐Min , Mai Yiu‐Wing
Published: March 2005

A simple theoretical model is developed to analyze the fiber frictional sliding resistance in a fiber bundle pushout test. The effect of the radial constraint imposed by the neighboring fibers on the stress transfer and frictional pushout stress is included in this analysis. Comparisons of theoretical results of this study and those of two existing fiber pushout models (i.e., single‐fiber pushout and three–cylinder) are also presented. For SiC–RBSN and SiC–glass composites with short embedded fiber lengths less than 1 mm, there is little difference between all these models. However, for larger embedded fiber lengths, the present model gives the highest frictional pushout stress caused by the more realistic radial constraint condition used in the analysis.
Viscosity of Molten Na2O─B2O3 Slags
Authors: Tandon Sashi , Agrawal Ranchhor D. , Kapoor Madan L.
Published: March 2005

The viscosity of sodium borate slags at high Na2O concentrations (37.3 to 49.4 mol%) and high temperatures (1000° to 1300°C) follows an Arrhenius‐type relationship. This relationship was also observed for sodium borate slags (mass% Na2O/mass% B2O3= 0.86) containing CaO and CaF2 for the same temperature range. There has been a reduction in viscosity of the sodium borate slags (mass% Na2O3mass% B2O = 0.53 to 0.86) with increase in Na2O concentration. On adding CaO (10 to 50 mass%) to the sodium borate slag (mass% Na2O/mass% B2O3= 0.86), the viscosity increased considerably, while an addition of CaF2 (S to 15 mass%) to the slag (30.9 mass% Na2O3 35.8 mass% B2O3, 33.3 mass% CaO) decreased the viscosity. The average activation energies of Na2O─B2O3, Na2O─B2O3─CaO3 and Na2O─B2O3─CaO─CaF2 slag systems have been estimated as 14.6, 124.7, and 41.4 kJ/mol, respectively, for the given composition ranges and 1000° to 1300°C temperature range.
Effect of BaWO4 on the Microwave Dielectric Properties of Ba(Mg1/3Ta2/3)O3 Ceramics
Authors: Yoon Ki Hyun , Kim Dong Pil , Kim Eung Soo
Published: March 2005

Physical and microwave dielectric properties of complex perovskite Ba(Mg1/3Ta2/3)O3 ceramics have been investigated as a function of the amount of BaWO4 in the temperature range from 20° to 80°C at 10.5 GHz. Up to 0.05 mol BaWO4 addition, the lattice constant ratio (c/a), ordering parameter, apparent density, and unloaded Q all increase, due to the increase in the substitution of Ta5+ ions of Ba(Mg1/3Ta2/3)O3 by W6+ ions from the melted BaWO4 at above 1430°C. With further addition of BaWO4, the unloaded Q decreases, due to an increase of the BaWO4 phase. The temperature coefficient of resonant frequency (TCF) can be controlled by the volume mixture rule of Ba(Mg1/3Ta2/3)O3 and BaWO4. When 0.09 mol BaWO4 is added, TCF becomes 0 ppm/°C.
Characterization of IgG monoclonal anti‐cardiolipin/anti‐β2GP1 antibodies from two patients with antiphospholipid syndrome reveals three species of antibodies
Authors: Zhu Min , Olee Tsaiwei , Le Dzung T. , Roubey Robert A. S. , Hahn Bevra H. , Woods, Jr Virgil L. , Chen Pojen P.
Published: March 2005

Antiphospholipid antibodies (aPL), including antibodies detected in anti‐cardiolipin (aCL) enzyme‐linked immunosorbent assays and in lupus anticoagulant (LA) tests, are strongly associated with recurrent thrombosis and recurrent fetal loss, i.e. the antiphospholipid syndrome (APS). Although recent studies suggest that most APS‐associated aCL are directed against the phospholipid (PL)‐binding plasma protein β2‐glycoprotein 1 (β2GP1), the precise nature of aCL binding specificities remains controversial. To address the issue of aCL specificity we generated five new monoclonal IgG aCL from two patients with APS. Characterization of these five aCL, as well as two previously published IgG aCL, revealed three patterns of reactivity: (1) four antibodies reacted strongly with human β2GP1‐cardiolipin (CL) complexes and weakly with human β2GP1 alone; (2) two antibodies recognized bovine β2GP1, but not human β2GP1; (3) one antibody reacted with complexes of human β2GP1 and CL, but not with human β2GP1 alone. Only one monoclonal displayed weak LA activity. These patient‐derived IgG monoclonal antibodies, and additional ones to be generated, may help define varying species of antibodies detected in aCL assays and identify the specific antibodies that may be pathogenic.
Eczema herpeticum: a case report
Authors: KHAN M. S. , SHAW L. , CLARK V. , AFZAL Z.
Published: March 2005

Primary herpetic gingivostomatitis is a relatively common and well‐recognized condition that the dental practitioner may encounter in clinical practice. A primary herpetic infection in a child with atopic dermatitis such as eczema, however, predisposes them to eczema herpeticum. This can be a severe and potentially life‐threatening condition. This paper describes one such case, discusses the aetiology, presentation and management of this condition, and highlights the importance of early recognition by the clinician.
The dental management of a patient with hyperimmunoglobulinemia E syndrome: a case report
Authors: MCAULIFFE N. J. , HUNTER M. L. , KAU C. H. , HUNTER B. , KNOX J.
Published: March 2005

Hyperimmunoglobulinemia E recurrent infection syndrome (also known as Job's syndrome) is a rare multi‐system primary immunological disorder in which non‐immunological abnormalities of the dentition, bones and connective tissue are also seen. A previous study has reported the occurrence of dental abnormalities in three‐quarters of individuals diagnosed as suffering from this condition. The present authors report the case of a boy whose prolonged retention of the primary dentition was associated with delayed eruption of permanent teeth. They emphasize the need for early intervention in order to help minimize later orthodontic problems.
Provocation of Kainic Acid Receptor mRNA Changes in the Rat Paraventricular Nucleus by Insulin‐Induced Hypoglycaemia
Authors: Koenig J. I. , Cho J. Y.
Published: March 2005

Hypoglycaemia induced by insulin injection is a powerful stimulus to the hypothalamic‐pituitary‐adrenal (HPA) axis and drives the secretion of corticotropin‐releasing hormone and vasopressin from the neurones in the paraventricular nucleus (PVN), as well as the downstream hormones, adrenocorticotropic hormone and corticosterone. In some brain regions, hypoglycaemia also provokes increases in extracellular fluid concentrations of glutamate. Regulation of glutamatergic mechanisms could be involved in the control of the HPA axis during hypoglycaemic stress and one potential site of regulation might be at the receptors for glutamate, which are expressed in the PVN. Insulin (2.0 IU/kg, i.p.) or saline was administered to adult male Sprague‐Dawley rats and the animals were sacrificed 30 min, 180 min and 24 h after injection. The amount of several kainic acid‐preferring glutamate receptor mRNAs (i.e. KA2, GluR5 and GluR6) were assessed in the PVN by in situ hybridisation histochemistry. Injection of insulin induced a rapid fall in plasma glucose concentrations, which was mirrored by an increase in plasma corticosterone concentrations. KA2 and GluR5 mRNAs are highly expressed within the rat PVN, and responded to hypoglycaemia with robust increases in expression that endured beyond the period of hypoglycaemia itself. However, GluR6 mRNA is expressed in the areas adjacent to the PVN and hypoglycaemic stress failed to alter expression of this mRNA. These experiments suggest that kainic acid‐preferring glutamate receptors are responsive to changes in plasma glucose concentrations and may participate in the activation of the PVN neurones during hypoglycaemic stress.
Encounters with exclusion through disability arts
Authors: Allan Julie
Published: March 2005

This paper examines disability arts and its role in identifying exclusion and barriers to participation within society. The work of selected writers, poets and musicians is presented and its value as a form of ideological critique is explored. It is suggested that disability arts has the potential to succeed where other forms of ideological critique fail because of the way in which difference is deployed, playfully and pragmatically, in order to make a political difference.
PROBLEMS OF A CENSUS OF NATIONAL WEALTH
Authors: Kendrick John W.
Published: March 2005

This paper is essentially a summary of the book Measuring the Nation's Wealth (Volume 29, Studies in Income and Wealth, New York: National Bureau of Economic Research, 1964), which is the report of study directed by the author. The purpose o f the study was to assess the problems and possibilities of conducting a national census of real wealth as a basis for continuing wealth and balance sheet estimates for the U.S. economy, by major sector.

It is stressed that the balance sheets and wealth estimates should be designed as a consistent part of an integrated system of national income accounts. Thus, valuation (at market prices and/or depreciated replacement costs), sectoring, and type‐of‐asset detail in the basic data and derived estimates should be compatible with the flow estimates contained in the economic accounts. Consistency of stock and flow estimates facilitates analysis of inter‐relationships, and is helpful in the estimation process.

It is recommended that in the U.S. asset data by broad categories be collected as part of the recurring economic censuses and other reporting systems, but that detail on fixed reproducible assets (construction and equipment) at cost, by year or period of acquisition, be obtained from a small sample of respondents in each industry. The detail would be useful in its own right, and also permit revaluation of the assets by use of price indexes and depreciation rates to a current depreciated replacement cost basis. Where feasible, respondent estimates of market values would also be obtained.

The proposal is thus a compromise between the Japanese 1955 sample survey of assets, and the detailed wealth inventory of the U.S.S.R. which was begun in 1959. Preliminary work is now underway in the U.S. federal statistical agencies to expand collection of asset data, and to prepare comprehensive wealth estimates in the framework of the national income accounts.
THE UNITED NATIONS SYSTEM OF NATIONAL ACCOUNTS IN THE MIDDLE EAST
Authors: Porter R. S.
Published: March 2005

After an introduction setting out the general state of work on the national accounts in the Middle East the author considers the principal uses of national accounts statistics in less developed countries. The first group of uses discussed is in connexion with the measurement of growth and the making of international comparisons. The author is of the opinion that in many cases the primary statistical series are so weak that the fact they they are combined together into a series called national income or gross domestic product lends to them a significance which they do not really possess. The real problem is to improve the quality of the primary series.

A second use of national accounts statistics is in connexion with fiscal and budgetary policy. In the statistically advanced countries this is one of the most important uses but in the less developed countries budgetary policy has not yet reached a level of sophistication which would call for the use of national accounts data. Moreover, the time factor involved in assembling accurate national accounts estimates militates against their effective use for short term forecasting.

The author considers that the most important use for national accounts statistics is to provide a framework for development planning. The United Nations system is not altogether appropriate for this purpose. It grew up primarily as a system for recording income flows but in development planning one is concerned equally with commodity flows with a great deal of attention being focussed upon intermediate products. The proposals of the working group of African Statisticians for an adaptation of the S.N.A. to African countries represents a most important advance in this respect.

In the final section of the paper the author advocates a broader definition of capital formation to include developmental expenditure which is not properly defined as fixed capital formation. Education expenditure is cited as an example. It is suggested that in the national accounts it would be desirable to operate with gross concepts. However, the growth of the capital stock is obviously important in less developed countries and it is suggested that statistical techniques be devised to measure it directly wherever possible. Finally, attention is drawn to the ambiguities and weaknesses in the concept of residence as used at present in the S.N.A.
A STATISTICAL ANALYSIS OF PRODUCTIVITY IN SELECTED SERVICE INDUSTRIES IN THE UNITED STATES, 1939–1963
Authors: Fuchs Victor R.
Published: March 2005

This paper examines differentials in output, employment and productivity across seventeen service industries in the United States from 1939 to 1963. Included are 9 retail trades and 8 services mostly from the personal service group. The industries chosen were those for which it was possible to obtain from available data reasonably comparable measures of output and input for selected years since 1939. Also, they are industries for which it is possible to calculate a measure of real output that is not based on labor input.

Sixteen of the industries show positive rates of change of real output per man. Thus there appears to be no basis for assuming that productivity cannot or does not increase in industries providing services. However, the rate of increase for the group as a whole was not as rapid as in manufacturing or in goods production as a whole.

The data for the seventeen industries give strong support to the hypothesis of a positive correlation between industry rates of growth and rates of change of productivity. The correlations are of the same order of magnitude as those found by other investigators in studies of manufacturing industries.

The coefficient of correlation between growth of output per man and growth of output is .93; between growth of output per man and growth of employment it is .54 for 1939–1963. The comparable coefficients for the 1948–1963 period are .70 and .13.

The results also parallel those reported for manufacturing in one other respect, namely, the absence of any correlation between changes in output per man and changes in compensation per man.

The paper concludes with a discussion of the problems encountered in measuring changes in real output in these industries and presents some alternative estimates based on different concepts and different sources.
THE ACCOUNTS AND THE COMPUTER
Authors: Lebergott Stanley
Published: March 2005

(1) The primary contribution from the computer's application to the national accounts may well be to erode the line between micro and macro analysis. Key macro totals in the accounts sum individual company reports. The computer permits us to develop distributions of these reports. Such distributions, regularly presented, would permit discovery of the first forerunners of change, would help distinguish, e.g., widespread strength in an export drive or a profits surge, from participation by a few major concerns that dominate the aggregate.

(2) The strikingly different parameters in cross section and time series studies (e.g., price elasticity of housing) will in some measure reflect incomparability between the micro data that enter into each. The computer makes possible the use of the wide array of micro data that really underly the accounts to develop consistent analyses of time series (of both aggregates and distributions) and cross section analyses.

(3) The inconsistencies now imbedded in the accounts but gilded over by the abilities of the estimators are well‐known. Discussions of wage price policy rest on data for wages that have no necessary compatibility with data on profits, etc. But since 1,500 corporations account for at least half of U.S. net income, sales, and investment, the computer can test the consistency of reports made by different units in these firms to different agencies—a process totally out of the question before the computer.

(4) The potential that the computer offers for prompt revisions in the accounts; for revisions by systematic rule; for tests of sensitivity of the entire set of accounts to particular tailor‐made adjustments, is clear.

(5) Company purchase orders and accounts are increasingly recorded on cards or tapes. From these we may derive input‐output detail and process detail that are light years better than those now feasible from intermittent survey aggregates.
AN APPROPRIATE SYSTEM FOR DEFLATION OF SECTORAL INCOME IN A DEVELOPING ECONOMY ILLUSTRATED BY THE INDUSTRIAL SECTOR OF THE INDIAN ECONOMY FROM 1951 to 1965*
Authors: Mathur P. N.
Published: March 2005

The technique of national income accounting is a part of what Hicks has termed “The Fixprice Method”. Deflation is an attempt to approximate a real economy to a fixprice economy. It is shown that if the propositions of macro‐dynamics are to hold, this deflation cannot be done in accordance with the price structure prevailing at any particular historical time, but must use that given by the capital theory of value, viz., when returns to labour are equal to zero. For a labour‐abundant developing economy this will correspond to prices based on opportunity cost principles.

As an illustration, sectoral incomes on this basis have been calculated for the industrial sector of the Indian economy for the years 1951 to 1965.
DEPRECIATION, OBSOLESCENCE, AND THE MEASUREMENT OF THE AGGREGATE CAPITAL STOCK OF THE UNITED STATES 1900–1962
Authors: Tice Helen Stone
Published: March 2005

This paper is concerned with the sensitivity of estimates of the aggregate capital stock of the United States to the statistician's choice of depreciation method. The usual depreciation charge can be shown to include allowances both for physical deterioration and for obsolescence. If one interprets the gross stock as the stock of surviving assets, then the various net stocks defined by depreciation accounting may be interpreted as a revaluation of these assets by means of an index of embodied technical change. Estimates of the United States capital stock were generated under eight sets of assumptions. These estimates are compared with respect to level, trend, and implications for other aggregate statistical indicators. The conclusion is reached that the assumptions which define a country's stock of tangible capital are of considerably greater importance than has often been supposed.
A NAIVE HISTORY OF INDIVIDUAL INCOMES IN WISCONSIN, 1947–1959
Authors: David Martin , Miller Roger , Moyer Eugene , Bauman Richard , Schneidemesser Michael von
Published: March 2005

The paper develops a descriptive history of the changing level and sources of income of the male population of Wisconsin from 1947 to 1959, as a preliminary step in building a model of income determination. The history is based on data from a one percent sample of the taxpaying population of Wisconsin from 1947 to 1959. Analysis of income sources received by male birth cohorts is followed by summary data on individual income variation.

Changes in earnings of birth cohorts appear to be determined by changes in labor force participation, general productivity increases, and acquisition of skills. Education, as reflected in occupational status, appears to affect the initial level and lifetime profile of earnings; however, education has played a changing role in the dynamics of earnings.

Movements in non‐earned income appear to be determined by rising real yields on capital, accumulation of wealth, and possibly by asset conversion and selective migration and mortality favoring wealth holders. Cohort asset accumulation for the period seems to have been determined by the growth rate of earnings, life cycle contingencies, and the pattern of asset prices and yields during the period.

Analysis of individuals’ incomes over the period reveals great heterogeneity of experience of individuals within birth cohorts and within occupations. This suggests that study of micro units is necessary to obtain behavioral information obscured in aggregate cohort data.
PRICE STATISTICS REQUIRED BY DEVELOPING COUNTRIES FOR NATIONAL ACCOUNTING PURPOSES
Authors: Braithwaite Stanley N.
Published: March 2005

In both developed and developing countries, the national accounting statistician who wishes to establish a composite set of values in current and base year prices is faced with a series of difficulties arising from a lack of indicators which are adequate for relating quantities and values within the national accounting framework. Consequently, ad hoc solutions are extensively adopted and use is made of price data which in the majority of cases have been collected for completely different purposes. The inter‐relationship of prices, quantities and values fundamental to the compatibility of the national accounts can therefore be, and often is, a rather tenuous one. In the case of many developing countries, the situation is accentuated by a very volatile behaviour of prices, a greater impact of price change and a much greater scarcity of useable statistical material. In addition, since structural change is frequently implicit in a development process, the pattern of values and of prices is often variable and irregular—this in turn creates problems in determining relative importance, in assigning weights and in imputing for prices of items not directly entering into the calculation of the indicators.

This paper analyses the series which are most commonly available, it points out the major deficiencies or limitations and it attempts to formulate a few guide‐lines for determining priorities called for in an integrated network of price statistics.
THE CASE AGAINST DIVISIA INDEX NUMBERS AS A BASIS IN A SOCIAL ACCOUNTING SYSTEM*
Authors: Merrilees W. J.
Published: March 2005

The purpose of this paper is to explore the question of at what stage should Divisia index numbers be introduced–within the social accounting schema proper or in the explanatory stage following? Three major reasons are given to support the case that Divisia index numbers have no role to play in measurement, but should and do provide a powerful tool in the explanation of productivity change.
FLOW‐OF‐FUNDS ACCOUNTS IN EASTERN EUROPE*
Authors: Garvy George
Published: March 2005

There is increased interest in flow of funds analysis due to the greater role assigned to money and to financial processes in the economic reforms now being implemented in Eastern Europe. After presenting a history of financial flows analysis, the paper describes data sources, and sectoring procedures. The efforts of particular countries are then reviewed and compared.
AN EMPIRICAL ESTIMATE OF THE RELATION BETWEEN TWO MEASURES OF ECONOMIC WELFARE*
Authors: Stoikov Vladimir
Published: March 2005

The main objective of this paper is to explore and quantify the difference between two measures of comparative economic welfare: (a) the more or less conventional measure of per capita national income, and (b) the capitalized value of expected future income per capita. The paper begins with a brief summary of the argument in favor of the present value of expected future income per capita as a measure of economic welfare. This is followed by an examination of the empirical relationship of the ratio of the suggested alternative measure to per capita income and an analysis of the variables used to compute the present value of expected income per capita. The main conclusion drawn from the calculations is that very substantial differences occur in the measurement of relative economic well‐being depending on which measure is used. A final section discusses the implications of this finding for international comparisons of economic welfare.