bluuebunny/crossref_metadata_2025 huggingface dataset:
Fair Value Accounting for Property-Liability Insurers and Classification Decisions under FAS 115
Authors: Godwin Norman , Petroni Kathy , Wahlen James
Published: July 2017

The first objective of this study is to describe the substantial differences across property-liability insurers in accounting classification decisions for fixed maturity securities during 1991–1995. This period includes the years before adoption, upon initial adoption, and after adoption of Statement of Financial Accounting Standards No. 115 (FAS 115, “Accounting for Certain Investments in Debt and Equity Securities”). The second and more important objective of this study is to test two risk-based explanations for differences in investment classification decisions under FAS 115. Under this new standard, firms are required to classify fixed maturity investment securities into trading portfolios, available-for-sale portfolios, or held-to-maturity portfolios. These classification decisions determine whether these securities are recognized at fair value or historical cost. On one hand, the decision to classify securities as available-for-sale rather than held-to-maturity (and thus apply fair value accounting) increases the time-series volatility of key accounting numbers such as owners' equity and total assets, which may be costly for insurers with low tolerance for accounting volatility. On the other hand, the choice to classify securities as available-for-sale (and thus apply fair value accounting) reduces liquidity risk because the accounting standards (and SEC enforcement practices) limit management's ability to sell securities that are not recognized at fair value. The empirical analyses examine whether the security classification decisions of the sample property-liability insurers are associated with firm specific characteristics that reflect liquidity risk and the tolerance for accounting volatility. The findings show that managers of property-liability insurers make tradeoffs between liquidity risk and concerns about accounting volatility when making investment classification decisions under FAS 115.
Discussion: “Fair Value Accounting for Property-Liability Insurers and Classification Decisions under FAS 115”
Authors: Santomero Anthony M.
Published: July 2017

Godwin, Petroni and Wahlen, henceforth, GPW, have presented us with the results of an interesting study of the impact of FAS 115 and the 1995 one-time option to alter the reporting of investment securities of property-liability insurers. But, like all good papers this one raises as many new questions as it answers old ones. The center of the study is how and why these insurers changed their investment asset reporting in light of the introduction of the three FAS 115 categories for investment securities of “trading securities,” “available-for-sale,” and “held-to-maturity.” The authors have meaningfully contributed to the literature in this area, as the reader learns much about the change in investment accounting over the period 1991–1995 in the earlier descriptive section of the paper, and the empirical portion sheds new light on the reasons for these changes.
Discussion: “Earnings and Risk Changes around Private Placements of Equity”
Authors: Jain Prem C.
Published: July 2017

Hertzel and Rees provide a rational explanation for a positive stock market reaction to the announcements of private sales of common equity by publicly traded firms. While previous research by Wruck (1989) and Hertzel and Smith (1993) focused on studying returns to equity holders, Hertzel and Rees focus on examining why the stock returns around the announcements are significantly positive. The authors examine two potential explanations: a change in risk and a change in future earnings. Their empirical findings are consistent with a change in earnings explanation but not with a change in risk explanation.
Nutritional Status of Nursing Home Patients
Authors: Shaver Harry J. , Loper Judy A. , Lutes Richard A.
Published: July 2017

Nutritional surveys were conducted on all 115 patients of a Medicare‐approved nursing homo. The techniques of nutritional assessment used included anthropometric measurements (weight/height, triceps skinfold, arm‐muscle and arm circumference), biochemical and hematologic tests (serum albumin, serum transferrin, total lymphocyte count, hemoglobin, and hematocrit), and an intradermal skin test for cell mediated immunity. The prevalence of protein‐calorie malnutrition (PCM) of moderate to severe degree was very high by currently used standards (weight/height, 43%; triceps skinfold, 37%; arm‐muscle circumference, 85%; serum albumin, 32%; serum transferrin, 38%; and total lymphocyte counts, 22%). Anemia was found in 52% of the men and 14% of the women by normal adult standards; in addition, 19% of the patients had negative cell‐mediated immunity (CMI) tests. The mortality rate during the 6 months after surveying was 13% for the immunocompetent (CMI‐positive) patients and 48% for the anergic (CMI‐negative). These findings confirm that PCM is prevalent in 85% of nursing home patients according to currently accepted nutritional assessment standards. In this nursing home population, 48% had marasmus, 35% had marasmus‐kwashiorkor mixed syndrome, and 2% had kwashiorkor. Perhaps new standards need to be derived for such specific age groups as the elderly.
Parenteral Feeding in Patients with Carcinoma of the Esophagus Treated by Surgery: Energy and Nitrogen Requirements
Authors: Moghissi Keyvan , Teasdale Peter R.
Published: July 2017

Nutritional assessment and requirements of patients with carcinoma of the esophagus treated by surgery are based on three series of patients: 1) the nutritional state of 22 assessed on admission, using recognized nutritional markers, the majority of whom were found nutritionally deficient; notably 72% were in negative nitrogen (N) balance. 2) Another series of 52 patients was based on the relationship between dysphagia and loss of weight and negative N balance; 48% were severely dysphagic and had lost an average 8.5% of their usual weight, and 89% were in negative N balance. Thus, the association between the two clinical markers and the N balance was clearly indicated. 3) Postoperative calorie and N requirements necessary to maintain a positive N balance were assessed and found to be 40 to 45 kcal/kg body wt and 0.2 to 0.25 g N/kg body wt.
Therapy for Thrombotic Occlusion of Long‐term Intravenous Alimentation Catheters
Authors: Glynn M.F.X. , Langer B. , Jeejeebhoy K. N.
Published: July 2017

Thrombosis and infection are closely related complications of implanted silastic catheters. A procedure, by which the thrombi are dispersed with urokinase while the catheter remains in situ, was uniformly successful in clearing the line in 20 patients, although in 5 the infusion had to be repeated 24 hr later. Catheter‐associated infections are rendered susceptible to antibiotics as the infected thrombotic nidus is lysed and the organisms exposed. In 7 patients, 4 of whom were taking antibiotics, fever and blood cultures became negative. The procedure results in no detectable systemic fibrinolysis or other complications.
New Isotherm for Multilayer Adsorption of Vapours on Non-Porous Adsorbents
Authors: Sircar S.
Published: July 2017

A new three-parameter isotherm equation to describe multilayer adsorption of vapours on non-porous adsorbants is derived. The model parameters are the monolayer adsorption capacity ( m) and two temperature dependent constants, C1 and C∞, which describe the adsorbate-surface interactions in, respectively, the first and the subsequent layers. The model can successfully describe the data for multilayer adsorption of ethanol, benzene and cyclohexane on cabosil in the entire relative saturation pressure range of zero to unity.
Gas Adsorption Operations: Equilibrium, Kinetics, Column Dynamics and Design
Authors: Sircar S. , Myers A. L.
Published: July 2017

Separation and purification of gaseous mixtures by adsorption has become a valuable tool in the chemical industry. Gas adsorption operations require information on both equilibrium and kinetics. Analytical equations are available to describe the adsorption of pure gases; mixture equilibria can be predicted by thermodynamic methods. Kinetic data suitable for column design can be expressed in terms of overall mass transfer coefficients. Design of columns for thermal swing adsorption (TSA) or pressure swing adsorption (PSA) processes requires the simultaneous solution of the partial differential equations for the material, energy and momentum balances describing the dynamics of adsorption in columns. Numerical solutions are usually required, but some useful analytical solutions are available for special cases.
Infrared Surface Studies of Opaque or Scattering Materials Using Photothermal Beam Deflection Spectroscopy
Authors: Low M. J. D. , Morterra C.
Published: July 2017

Infrared (IR) photothermal beam deflection spectroscopy (PBDS) is briefly described and some of its applications to studies of carbons and highly scattering materials are reviewed. PBDS is especially useful for the study of materials which absorb IR radiation very strongly or act as strong IR scatterers, so that conventional IR techniques fail. Application of PBDS to study the thermal degradation of a phenol-formaldehyde resin, the reaction of NH3 and H2O with the surfaces of intermediate-temperature chars, the effect of Fe3+ on the charring of cellulose, the dehydration of titanyl sulphate, and TiO2 pigments, are described.
Characterization of Carbon-Supported Iron Catalysts Prepared from Fe(CO)5
Authors: Guerrero-Ruiź A. , López-González J. de D. , Mata-Arjona A. , Romero-Sánches V. , Rodríguez-Ramos I.
Published: July 2017

Iron catalysts have been prepared by adsorption of iron pentacarbonyl on activated carbon. After reduction in H2 flow at different temperatures, metal dispersions and average crystallite sizes have been studied. The catalysts have been characterized by H2 and CO chemisorption at 373 K, X-ray diffraction line broadening and transmission electron microscopy. The results obtained show that the iron crystallites prepared by this method present a narrow particle size distribution and that the iron catalysts have high metal dispersions. It may be concluded that CO chemisorption at 373 K can be a good technique to study iron supported catalysts.
An Attempt to Apply Analogs of the Dubinin-Radushkevich and Freundlich Equations for Describing Isotherms of Adsorption from Binary Liquid Solutions of Non-Electrolytes with Unlimited Miscibility
Authors: Garbacz J.K. , Biniak S. , Cysewski P.
Published: July 2017

An extention of the Dabrowski and Jaroniec concept of describing adsorption from binary liquid solutions of non-electrolytes on solids in terms of the Dubinin-Radushkevich (DR) and Freundlich (F) equations is presented. A new solution has been advanced based on the definition of the chemical affinity of the process of generation of equilibrium bulk phase from the pure components of the solution. The real adsorption isotherm equation has been formulated in which particular cases are the quasi-DR equation and the quasi-F equation. Some adsorption systems are described.
Argon and Nitrogen Physical Adsorption on Boron Nitride
Authors: Bottani E.J. , Zarate J.R. , Cascarini De L.E. Torre
Published: July 2017

Physical adsorption isotherms of N2 and Ar on boron nitride are analysed and the behaviour of the adsorbed phase is discussed. Different models are used to interpret the adsorbed states. The behaviour of the BET C parameter suggests that a phase-transition occurs in Ar adsorption which is not showed in its isotherm. Adsorption energies distribution functins are calculated using a double Gaussian as distribution function. Nitrogen cross-sectional areas, under experimental conditions are estimated respect to those of the Ar.
Theory of the Adsorption Dynamics of Vapours on Microporous Adsorbents. 1. Introduction into the Model of a Layer of Equilibrium Adsorption
Authors: Larin A.V.
Published: July 2017

The possibilities arising from the introduction of a layer of equilibrium adsorption into the model for a theory relating to the adsorption dynamics of vapours on microporous adsorbents have been studied. The initial first-order differential equation of the model combines the features of a material balance equation, the adsorption kinetics and an unsimplified isotherm. The results of computer simulation for the Dubinin-Radushkevich adsorption isotherm agree closely with the experimental data for ethyl chloride and carbon tetrachloride adsorption dynamics on activated carbons over a wide range of breakthrough concentrations.
Adsorption Equilibria of Basic Dyestuffs onto Maize Cob
Authors: El-Geundi Mohammad S.
Published: July 2017

Equilibrium isotherms have been determined for the adsorption of basic dyestuffs, namely, Basic Blue 69 (BB 69) and Basic Red 22 (BR 22), onto maize cob. The experimental results have been fitted with Langmuir, Freundlich and Redlich–Peterson isotherms. The maximum adsorption capacity of the maize cob was found to be 160 mg dye per g maize cob for BB 69 and 94.5 mg dye per g maize cob for BR 22. The relative costs of dye removal are reported based on adsorption capacity only; the cost of removal of BB 69 and BR 22 using maize cob was only 4.1% and 8.3%, respectively, that of activated carbon.
Application of Activated Carbon to Decolouration in the Sugar Industry. Part I. Determination of the Physical and Chemical Properties of Activated Carbon
Authors: BlasińSki Henryk , Kamionowska Urszula , KaźMierczak Janusz , Pustelnik Anna
Published: July 2017

The decolouration of technical sugar solutions (thin juice) on six different activated carbons has been investigated. The parameters of the porous structure and the number of surface functional groups have been determined for each adsorbent. It has been found that the activated carbon used in the sugar industry exhibits better decolouring properties the greater the number of mesopores, super-micropores and surface basic groups it possesses.
On the Temperature Dependence of Adsorption of Organic Materials from Aqueous Solution
Authors: Radeke K.H. , Hartmann G.
Published: July 2017

Adsorption studies of phenol and aniline from aqueous solution on to various active carbons are reported. The data indicate a maximum dependence for adsorption with temperature for both adsorbates, with that for aniline being considerably above the normal freezing point for the liquid. It is concluded that such anomalous behaviour cannot be attributed solely to a higher packing density for the adsorbate above its melting point as previously suggested and that some other thermodynamic reason must be sought.
Derivation of the Expanded Form of the BJH Equation and its Application to the Pore Structure Analysis of Mesoporous Adsorbents
Authors: Masthan S. Khaja , Rao K.S. Rama , Prasad P.S. Sai , Rao P. Kanta
Published: July 2017

The BJH equation, [Formula: see text], used for pore structure analyses via its application to the N2 desorption isotherms at 78 K of porous materials, has been modified by substituting the value of ci and expanding the last term. The quantity vn is the volume of the pores involved in the nth desorption step and is given in terms of the volume of N2, (ΔV)n, exuded from the porous material, the constants Rn and ci which depend on the average pore size and average thickness of the physically adsorbed multilayer, Δtn being the decrease in thickness of the multilayer as a result of the nth desorption step and Ai the surface area of the set of pores involved in the ith desorption step. A derivation of the modified equation is presented. It has been applied to the N2 desorption data of bone char used by Barrett, Joyner and Halenda (BJH). The effect of the multilayer thickness (t) values given by Pierce and de Boer on the pore size distribution of bone char has been studied. The pore size distribution data are compared with those obtained by the original BJH and Pierce methods. The pore system conforms very well with the idealised open-ended cylindrical pore model.

The expanded BJH equation has also been applied to the desorption isotherms of fresh and sintered silica-alumina cracking catalysts over the entire range of silica/alumina ratios. The multilayer thickness (t) values given by de Boer have been used in the calculations. The pore systems of the catalysts, vacuum-dried at 400°C, are observed to conform to the cylindrical pore model as revealed by the excellent agreement between the cumulative surface areas obtained in P.S.D. calculations and the BET surface areas. The pore systems of the catalysts, sintered at different temperatures in a dry oxygen stream, deviate considerably from the cylindrical pore model. Enlargement of the pores and their nonconformity with the ideal pore model are attributed to modifications of the pore structures brought about by the phenomenon known as ‘self-steaming’ with the water vapour released from the catalysts.
Useful Adsorption Equilibriums by Means of Natural Clay
Authors: Hawash S. , El-Abd H. , El-Geundi M.S. , Nassar M.M. , Farah J.Y.
Published: July 2017

Equilibrium isotherms have been determined for the adsorption of nickel onto natural clay. The experimental results have been fitted using the Freundlich, Langmuir and Redlich-Peterson isotherms. The maximum adsorption capacity of the clay was found to be 12.5 mg/g. The relative costs of nickel removal are reported based on adsorption capacity alone and are found to be 2.8% of that of activated carbon.
Changes in the Surface Area of Silica-supported 12-Molybdophosphoric Acid in Relation to the Degree of Loading and the Calcination Temperature
Authors: Khalil L.B. , Mourad W.E. , Girgis B.S.
Published: July 2017

A technical silica gel (Grace-113) was impregnated with 12-molybdophosphoric solution to attain loadings of 0.72–13.4 wt.%. The air-dried solids were then calcined for 3 h at 400, 600 and 800°C, respectively, followed by determination of their N2 adsorption isotherms. The silica gel was thermally stable and suffered about 15% loss in area at 800°C. The impregnated silicas showed considerable decrease in surface area as a function of their heteropoly acid content. Two processes are suggested as taking part in the modification of pore structure: (1) diffusion of the aqueous heteropoly acid solution and its subsequent deposition; and (2) dissolution of silica gel in the acidic aqueous solution followed by interaction with HPMo to form either molybdosilicate or P–Si exchange products. Correlation with the previously studied catalytic conversion of isopropanol indicated that the activity was independent of the surface area. Catalytic dehydration on the 600°C and 800°C products seems to be associated with silicate, molybdate or MoO3 surface species rather than being due to surface acidity or the extent of the surface area.
High-pressure Methane Adsorption on Natural and Synthetic Zeolites
Authors: Mentasty L. , Woestyn A.M. , Zgrablich G.
Published: July 2017

The adsorption isotherms of methane on synthetic (5A and 13X) and natural (Erionite) zeolites at different temperatures have been obtained through the use of a high-pressure volumetric adsorption apparatus over the pressure range 0–5 MPa. The isotherms have been analyzed on the basis of a statistical thermodynamic adsorption model, variation in the temperature allowing calculation of the isosteric heat of adsorption. The results show that these zeolites are highly efficient for methane storage at moderately low pressure (0.5–1 MPa).
Adsorption of Acetone and Cumene on Activated Carbon. I. Single-component Adsorption Equilibria of Acetone and Cumene on Supersorbon HS-4
Authors: Besedova Eva , Bobok Daniel
Published: July 2017

Adsorption equilibrium data for the systems acetone/activated carbon and cumene/activated carbon measured over the pressure ranges 0.2–20 500 Pa and 2–420 Pa, respectively and over the temperature range 10–120°C have been fitted to the Langmuir, O'Brien–Myers and Toth isotherms, as well as the Dubinin-Astakhov equation. The best fit with the experimental data was obtained using the Toth isotherm and the Dubinin–Astakhov equation.
Characterization of Activated Carbons by the BET Equation — An Alternative Approach
Authors: Parra J.B. , Sousa J.C. De , Bansal Roop C. , Pis J.J. , Pajares J.A.
Published: July 2017

The adsorption isotherms of nitrogen at 77 K have been determined on two series of activated carbons and two samples of activated carbon fibres. The carbons were highly microporous and contained varying amounts of different forms of microporosity. Characterization of the carbons was undertaken using an alternative linear form of the BET equation and the results of the BET parameters obtained have been compared with those obtained from the usual classical linear form of the equation. The surface areas calculated from the two linear forms were similar while the C values were quite different. The C values obtained from the alternative linear form appeared to be more reasonable, being consistent with and related to the microporous character of these carbons. The alternative linear form gave BET plots which were more sensitive to deviations from linearity allowing the relative pressure range for the application of the BET equation to be determined without any ambiguity and more precisely.
Controlled Gasification of Carbonaceous Materials in a Water Vapour Atmosphere. Part I. Description of the Process Kinetics
Authors: Grzegorczyk W. , Leboda R.
Published: July 2017

A gravimetric method of studying the gasification reaction of carbonaceous materials during active carbon modification by means of water vapour as well as a description of the reaction kinetics are proposed. The basic postulate of chemical kinetics was applied as a first-order dependence of the reaction rate on the carbon mass:

dm/dt = m · f(T) · g(c1)

The kinetic equation was experimentally verified over the temperature range 891–1068 K using a gas stream consisting of 90 vol.% H2O + N2. Statistical analysis of the approximation of the experimental data to the kinetic equation proved the corrections of the assumptions and the applicability of the description proposed to control the extent of gasification during active carbon modification.
Chemical Heterogeneity of Metal Oxide Surfaces as Studied by Inverse Gas Chromatography at Finite Concentrations
Authors: Bogillo V.I. , Shkilev V.P. , Voelkel A.
Published: July 2017

A method for the calculation of the heterogeneous solid surface distribution function on the adsorption (free adsorption) energy as the sum of two uniform functions and on parameters describing the donor–acceptor and dispersive properties of the adsorption sites direct from chromatographic peaks as measured by inverse gas chromatography of ‘test ’ adsorbates at finite concentrations has been proposed. Average parameters reflecting the donor–acceptor properties of the adsorption sites and the dispersive component of the free surface energy in the monolayer region for the individual and mixed Si, Ti and Al pyrogenic oxide surfaces were determined using this method from the adsorption data for 18 ‘test ’ compounds possessing different donor–acceptor and polarizable properties.
Carbon Dioxide Adsorption and Decolourizing Power of Activated Carbons Prepared from Pistacia Shells
Authors: Hourieh M.A. , Alaya M.N. , Youssef A.M.
Published: July 2017

A series of activated carbons ‘Z’ was prepared from Aleppo Pistacia Vera shells using different percentages of zinc chloride at 873 K in the absence of air. Another series ‘ZN’ was prepared using the same conditions as for the ‘Z’ series but employing a nitrogen atmosphere to effect carbonization. The textural properties of the two series of samples were determined from the adsorption of carbon dioxide and methylene blue at 298 K.

Activated carbons with a high adsorptive capacity for methylene blue were obtained. Activation with zinc chloride proceeded with increasing microporosity via the creation of new micropores. At high percentages of zinc chloride, slight partial pore widening may take place. Carbon dioxide was accessible to the entire pore system and was therefore suitable as a probe for the investigation of the textural properties of the activated carbons studied. A fraction of the porosity was inaccessible to methylene blue molecules and consequently lower surface areas were calculated from the adsorption of this dye molecule.
Polar Interactions at Carbon Surfaces Described by the Dubinin Equations and by an XPS-Based Model
Authors: Bradley R.H.
Published: July 2017

The interaction of polar molecules at carbon surfaces is briefly reviewed within the framework of the Dubinin theory. A linear relationship is observed between the term a0 of the Dubinin-Serpinski equation and heats of immersion calculated from equilibrium isotherms for water vapour adsorption by a series of microporous carbons with increasing polarities. A quantitative relationship is proposed between surface polarity, characterised by the spectroscopically measured surface oxygen concentration [O]T and calorimetric heat of immersion in water for a series of non-porous carbon blacks.
Adsorption of Mercury, Lead and Cadmium Ions on Modified Activated Carbons
Authors: Mostafa M.R.
Published: July 2017

Steam-activated and zinc chloride-activated carbons were prepared from rice husks. These carbons were modified by treatment with different concentrations of sulphuric acid. The adsorption of Hg2+, Pb2+ and Cd2+ ions from aqueous solution at 298 K on to these carbons has been investigated. The effect of pH on the adsorption capacity has also been studied.

The adsorption isotherms obtained were of the Langmuir type, the application of the Langmuir equation allowing the determination of the adsorption capacities. The chemistry of the carbon surface is a prominent factor which determines the removal capacity for these metal ions. In contrast, the extent of the surface is not a controlling factor in this regard.
Effect of γ-Irradiation on Some Surface and Catalytic Properties of Cr2O3/Al2O3 Solids Precalcined at 700°C
Authors: El-Shobaky G.A. , Ghozza A.M. , Mohamed G.M.
Published: July 2017

The effects of γ-irradiation (20–160 Mrad) on the surface characteristics (SBET, VP and r) and catalytic properties (in CO oxidation by O2) of chromia/ alumina solids have been investigated. The solids were prepared by mechanical mixing of CrO3 with finely powdered Al(OH)3, followed by drying at 120°C and calcination in air at 700°C. The amounts of chromia in the samples were 8.2 wt% and 27.1 wt%, respectively.

The results obtained show that doses of 20–40 Mrad brought about a measurable increase in the surface characteristics (SBET, 46%; VP, 93%; r, 31%) of the sample containing 27.1 wt% Cr2O3 but doses above this limit had the opposite effect. However, the various surface parameters of the sample treated with 160 Mrad were still higher than those of the untreated sample. With the sample containing 8.2 wt% Cr2O3, varying the dosage of γ-irradiation in the range 20–160 Mrad led to smaller variations in the surface parameters.

The catalytic activities of both types of sample were decreased by γ-irradiation, with the decrease being more pronounced for samples rich in chromia. Curves relating catalytic activity to dosage exhibited minima at 40 Mrad. The observed decrease in catalytic activity with γ-irradiation was attributed to a decrease in the concentration of catalytically active sites taking part in chemisorption and catalysis of the oxidation of CO by O2 without any change in their energetic nature.
Textural, Structural and Catalytic Properties of ZnCr2O4–A12O3 Ternary Solid Catalysts
Authors: El-Sharkawy E.A.
Published: July 2017

Two series of ternary solid catalysts containing Al, Cr and Zn but with different ZN2+ or Cr3+ ion contents were prepared by impregnation methods. All systems were calcined by heating within the temperature range 773–1073 K. Structural characterization of the systems was effected by X-ray diffraction (XRD) methods and by differential thermal analysis (DTA). The textural properties of the precalcined products were measured from adsorption/desorption studies of nitrogen at 77 K. The surface acidities of the precalcined products were also studied using a poisoning method employing pyridine as the probe base. The adsorption and disproportionation of NO at 298 K was followed via in-situ FT-IR spectroscopic methods, while the catalytic activities of the prepared samples towards the dehydration (DHD)/dehydrogenation (DHG) of propan-2-ol were studied using a pulse microcatalytic technique.

XRD and DTA analyses showed the presence of γ-A12O3 and ZnCr2O4 in the prepared samples but did not provide any evidence for other detectable species in the ternary solid materials. The disproportionation of NO, as well as the catalytic conversion of propan-2-ol, was apparently strongly influenced by the structural properties of these materials but to a lesser extent by their textural properties.
Oxidized BPL Carbons
Authors: Barton S.S. , Evans M.J.B. , Macdonald J.A.F.
Published: July 2017

A series of oxidized carbons has been prepared by treatment of the carbon with concentrated nitric acid at various temperatures, and the surface and adsorption properties of the prepared carbons studied. Water adsorption was modelled using a recently derived equation capable of predicting a value for the primary adsorption sites on the surface of a microporous carbon while fitting the experimentally determined isotherm at high relative pressures. The concentration of primary sites was seen to increase with increasing temperature of oxidation. The very highly oxidized carbon samples were found to have a significantly lower BET surface area determined from nitrogen desorption at 77 K and higher apparent density measured from mercury displacement.
Study of the Structure of a Surface-porous Adsorbent using the Gas Chromatographic Version of the Molecular Probe method
Authors: Tarasevich Yu.I. , Zhukova A.I. , Aksenenko E.V. , Bondarenko S.V. , Nazarenko O.V.
Published: July 2017

Results are presented of structural studies of a silica-based surface-porous adsorbent. It is shown that a reliable estimate of the size of the surface micropores of this adsorbent can be obtained using the gas chromatographic version of the molecular probe method. This is based on a comparison of the thermodynamic properties for the adsorption of substances of known molecular size on the surface-porous adsorbent with those characteristic for the adsorption of the same substances on to a non-porous adsorbent of a similar chemical nature.
Application of the DR and DS Equations to Benzene Adsorption from Water Solutions
Authors: Eltekova N.A. , Eltekov Yu.A.
Published: July 2017

Equations of the theory of micropore filling have been applied to the description of adsorption equilibria in systems containing microporous carbon and benzene solutions in water. The parameters of these equations have been evaluated from experimental data obtained for two commercial activated carbons. Comparison of the calculated and experimental adsorption isotherms suggest that these activated carbons are characterized by heterogeneous microporosity. The effect of water on the adsorption behaviour of benzene molecules in the micropores has been considered.
Validation of the Reliability of the Porous Structure Parameters for Activated Carbons as Evaluated on the Basis of Adsorption Isotherms from the Gaseous Phase
Authors: Trznadel Bogdan J. , Zietek Stefan , Światkowski Andrzej
Published: July 2017

Adsorption/desorption isotherms from the gaseous phase (benzene vapour, nitrogen) have been determined consecutively a number of times on the same activated carbon sample. The porous structure parameters were evaluated on the basis of the experimental data using the Dubinin-Radushkevich, Dubinin-Astakhov, Finger-Büllow, Dubinin-Stoeckli and Horvath-Kawazoe equations for the calculations. Analyses of the mean values and relative errors of particular structural parameters were made as well as comparisons of the stability of the adsorption models used. It was found that the reliability of the results obtained was better for the benzene vapour adsorption isotherms determined by a gravimetric method than for those determined by a volumetric method using nitrogen as the adsorbate.
Polymethacrylic Acid Adsorption and the Aggregation Stability of Titanium Dioxide Suspensions
Authors: Soltys M.M. , Yaremko Z.M. , Nykypanchuk D.M. , Fedushynska L.B. , Havryliv V.D.
Published: July 2017

The dependence of polymethacrylic acid adsorption on to two rutile samples of titanium dioxide on the adsorbent content in the system and the degree of neutralization of the macromolecules has been studied. A scheme for the adsorption and aggregation processes occurring under the experimental conditions employed has been proposed and a correlation between the extent of polyelectrolyte adsorption and the aggregation stability of the titanium dioxide suspensions established. The extent of adsorption decreased with increasing adsorbent content and this has been explained by the decrease in surface available for macromolecular adsorption. Such decreases can arise from coagulation processes as well as from incomplete redispersion of the titanium dioxide particles.

It has been shown that the maximum stability of the titanium dioxide suspensions occurs at polyelectrolyte concentrations well below the concentration necessary for adsorption saturation. As the degree of neutralization of the macromolecules increased the extent of adsorption decreased, the aggregation stability of suspensions in the presence of low molecular weight polymethacrylic acid remaining unchanged while that in the presence of high molecular weight poly-acid molecules decreased. The results obtained have been discussed in conjunction with the properties of aqueous solutions of partially neutralized polymethacrylic acid and changes in the conformations of the macromolecules.
Directional Permeability Measurement of Deformed Reinforcement
Authors: Hammami A. , Trochu F. , Gauvin R. , Wirth S.
Published: July 2017

This paper presents a method for the evaluation of the anisotropic permeability of deformed woven fabrics. In order to conform to complex shapes, the woven fabric must undergo a certain amount of deformation. This deformation disturbed the resin flow and the filling of the mold cavity in liquid molding processes such as resin transfer molding (RTM). It is important for computer simulations of the filling process to predict the change of directional permeabilities k, and k2 caused by the deformation of the fabrics. Several flow experiments were conducted on a nonstitched woven fabric with different deformation angles. The deformation affects the global permeability and the directional permeabilities k1, k2. At the same time, the principal permeability axes are shifted. The resulting permeability is related to the orientation of the fabric. This article presents characteristic permeability curves for the fabric JBMartin NCS 81053-A as a function of the shearing angle or, alternatively, of the resulting fiber fraction. It is possible to conclude that for the fabric tested, the shearing angle of the reinforcement will have a definite influence on the resin flow pattern.
Stress Failure Criterion for Laminated Composites
Authors: Yeh Hsien-Yang , Feng A.
Published: July 2017

The generalized Yeh-Stratton criteria is applied to calculate the fracture stress of multi-directional fibrous composite material with existing cracks or circular holes under uniaxial tensile load. The failure stresses were predicted and compared with the prediction of the theory of Nuismer and Whitney and the experimental data.

Based on this study, it is recommended that for cracks and circular holes with larger crack size and radius (>0.6 inch), the Yeh-Stratton failure criterion could be used as a proper design guide.
The Effects of Resin Thermal Degradation on Thermostructural Response of Carbon-Phenolic Composites and the Manufacturing Process of Carbon-Carbon Composites
Authors: Wang C. Jeff
Published: July 2017

Research in the effects of thermal degradation of phenolic resins on the anomalous behaviors in the thermostructural response of carbon-phenolic composites and in the manufacturing process of carbon-carbon composites was reviewed. Remarkable progress has been made in understanding the macroscopic fracture behavior of the composites, and in elucidating the interrelationships between thermal degradation, gas permeation, resin shrinkage, and composite expansion. Recent efforts have been focused on the fundamental understanding of the processing and property characteristics of the phenolic and carbon composites. However, some problems have been encountered in establishing a comprehensive, systematic understanding on the reactive mechanisms of those anomalous events. This paper begins by reviewing the occurrence of these anomalous behaviors in both processes. The restrained thermal growth (RTG) testing results are used to describe the complex thermostructural response of a phenolic composite in response to a heating environment, and to investigate the conditions for the anomalous events. Then, the effects of resin shrinkage, composite expansion, material microcracking, and gas permeation on the thermostructural response are presented. These are followed by a model framework on thermal degradation process of phenolic resins, and a micromechanical analysis of fracture mechanisms. Finally, this paper presents a brief discussion on the needs for the design of the optimum fiber-resin-filler interactions and concludes by pointing out future research directions in process modeling and expert system for the design of phenolic composites for thermal protection applications of carbon-phenolic composites and for the preparation of the carbon-carbon composites from the carbon-phenolic composites.
Experimental and Numerical Evaluation of Beam-To-Column Connections for Pultruded Structures
Authors: Bank Lawrence C. , Yin Jiansheng , Moore Lawrence , Evans David J. , Allison Ronald W.
Published: July 2017

This paper describes an experimental and theoretical investigation of beam-to-column connections for standard pultruded I and wide-flange structural shapes. Three different connection types were developed and tested. Results of the tests are presented in graphical moment-rotation data form. In addition, photographs and detailed descriptions of the failure modes of the different connections are provided. The results of this testing are compared with test data obtained for previously tested connection types. Recommendations for a "pultrudable" beam-to-column connection element are provided. In addition to the testing, numerical finite element work was performed using the COSMOS finite element code to determine whether the complex connection behavior could be accurately modeled by a numerical method. In this preliminary finite element investigation only linear elastic analysis was performed to obtain the initial moment-rotation characteristics of the connection. Results of the finite element work were very encouraging. Moment-rotation data obtained from the numerical analysis gave results which were comparable to those obtained from the tests. Further development of the finite element models would be required to predict the full non-linear moment rotation and failure characteristics of the connections. However, these results indicate that in the future preliminary investigations could be performed numerically rather than by the use of expensive and time-consuming tests.
Influence of Design on Mixing Efficiency in the Kneading Disc Region of Co-Rotating Twin Screw Extruders
Authors: Manas-Zloczower Ica , Cheng Hongfei
Published: July 2017

Co-rotating, intermeshing twin screw extruders are widely used in polymer compounding and blending. In this work, a fluid dynamics analysis package-FIDAP, using the finite element method was employed to simulate the isothermal flow patterns of a non-Newtonial fluid in the kneading disc region of Werner & Pfleiderer ZSK-30 and ZSK-53 corotating twin screw extruders. Dispersive mixing efficiency was analyzed in terms of shear stresses generated and elongational flow characteristics. The influence of design variables (2 lobes versus 3 lobes discs) on the pumping characteristics and dispersive mixing efficiency is discussed.
Prediction of Thermal and Fire Resistance of Phenolic Resins by Dynamic TG Analysis
Authors: Chtourou Halim , Atarsia Abdelatif , Fisa Bo
Published: July 2017

Industrial phenolic resins, normally used with acid catalyst, have been formulated into auto-catalyzed resins for B-stage prepreg production. Multi-component formulations have been prepared into three classes, A, B and C, showing fast (2-4 days), medium (7-9 days) and slow (14-18 days) thickening process, at room temperature. To optimize the formulations as a function of thermal and fire resistance, Thermogravimetric Analysis (TG), has been used. Cured samples from A, B and C classes, scanned from room temperature to 650'C, showed different thermal resistance as expressed by the weight loss.
The Fracture Behavior of Glass Fiber/Recycled PET Composites
Authors: Cantwell W. J.
Published: July 2017

The potential offered by glass fiber reinforced composite materials based on a recycled PET matrix has been investigated. Laminates containing both woven glass fabrics and chopped strand mats have been manufactured and tested under both quasi-static and impact conditions. Polished sections from a number of laminates have highlighted the high degree of fiber wetting and the low level of voiding in the laminates. Three point bend tests and Charpy impact tests on simple beam-like samples have shown that recycled polymer composites offer a range of mechanical properties similar to those associated with corresponding laminates based on virgin polymer matrices. A series of interlaminar fracture tests on the woven fiber composites have shown that the delamination resistance of these materials is comparable to that exhibited by relatively tough systems such as carbon fiber reinforced PEEK.
Lifting the lid off spin
Authors: Cockerell Michael
Published: July 2017

Michael Cockerell's BBC TV documentary News from Number Ten aroused great controversy, both before and after its transmission on July 15. Tony Blair and his press secretary Alastair Campbell had given Cockerell unprecedented access to film Number Ten's relatians with the media over the course of four months. Here Cockerell recounts what went on behind the scenes in the making of the documentary.
Antimony leaching from cot mattresses and sudden infant death syndrome (SIDS)
Authors: Jenkins R O , Craig P J , Goessler W , Irgolic K J
Published: July 2017

1 Polyvinyl chloride (PVC) cot mattress covers from SIDS cases were investigated as potential sources of soluble (potentially ingestable) antimony in the cot environment.

2 Body fluids (urine, saliva) and proprietary domestic detergents/sterilizing fluids markedly enhanced leaching of antimony from PVC. Release of antimony was also enhanced at both low and high pH and by elevated temperature. The extent of antimony leaching did not correlate well with PVC content of this element.

3 These data do not support the assumption that postmortem analysis of antimony content proves exposure to gaseous antimony trihydride from mattress PVC.

4 Ingestion of antimony released from PVC could account for the high variability associated with reported detectable levels of antimony in liver from both SIDS and other infants. It could also explain suspected additional postnatal exposure to this element, which gives rise to elevated levels of Sb in the hair of some healthy infants.
Lack of inhibition of human plasma cholinesterase and red cell acetylcholinesterase by antimony compounds including stibine
Authors: Hussain S Anjum , Jane David E , Taberner Peter V
Published: July 2017

1 The toxic gas hypothesis proposes exposure to stibine (antimony trihydride) generated from microbial contamination of cot mattress materials as a possible cause of unexplained death in infancy (SIDS) as a consequence of cholinesterase inhibition. We have measured the direct effects of antimony compounds including stibine on the activity of plasma cholinesterase, red blood cell acetylcholinesterase (AChE) and mouse neuronal AChE in vitro.

2 Colorimetric assays for the different esterases with potassium antimonyl tartrate or antimony trichloride at concentrations up to 1073 M inthepresenceof substrate concentrations sufficient to produce 80% of the maximum reaction rate produced no inhibition of enzyme activity. Exposure of enzyme preparations to stibine gas at concentrations sufficient to cause denaturation of red cell haemogloblin caused no measurable inhibition of esterase activity.

3 We conclude that stibine gas or soluble antimony compounds are not capable of inhibiting cholinesterase activity at toxicologically relevant concentrations.
Mechanism of action of honey bee (Apis mellifera L.) venom on different types of muscles
Authors: Nabil Zohour I , Hussein Aida A , Zalat Samy M , Rakha Miran Kh
Published: July 2017

1 The effect of crude honeybee (Apis mellifera)venom on the skeletal, smooth as well as cardiac muscles were studied in this investigation.

2 Perfusion of gastrocnemius-sciatic nerve preparation of frogs with 1 mg/ml venom solution has weakened the mechanical contraction of the muscle without recovery. Blocking of nicotinic receptors with 3 mg/ml flaxedil before bee venom application sustained normal contraction of gastrocnemius muscle.

3 The electrical activity of duodenum rabbits was recorded before and after the application of 1 mg/ml venom solution. The venom has depressed the amplitude of the muscle contraction after 15 min pretreatment with atropine nearly abolished the depressor effect of the venom on smooth muscle.

4 In concentrations from 0.5-2 mg/ml, bee venom caused decrease of heart rate of isolated perfused toad heart. This bradycardia was accompanied by elongation in the P-R interval. A gradual and progressive increase in the R-wave amplitude reflected a positive inotropism of the venom. Application of 5 mg/ml verapamil, a calcium channels blocking agent, abolished the noticed effect of the venom.

5 Marked electrocardiographic changes were produced within minutes of the venom application on the isolated perfused hearts, like marked injury current (elevation or depression of the S-T segment), atrioventricular conduction disturbances and sinus arrhythmias. Atropine and nicotine could decrease the toxic effect of the venom on the myocardium.

6 Results of the present work lead to the suggestion that bee venom is mediated through the peripheral cholinergic neurotransmitter system. General neurotoxicity of an inhibitory nature involving the autonomic as well as neuromuscular system are established as a result of the venom, meanwhile a direct effect on the myocardium membrane stabilization has been suggested.