bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption of Water on Activated Carbon — a Thermodynamic Study by Immersion Calorimetry
Authors: Friedrich M. , Radeke K.H. , Isirikyan A.A. , Vartapetyan R.S.
Published: July 2017

Heats of immersion of an industrial coke-based activated carbon into water have been measured as a function of water pre-adsorption. Using adsorption isotherm data, standard differential molar enthalpies and entropies of adsorption have been calculated. They illustrate the different molecular structures of the adsorbed water phase within the activated carbon. The two processes occurring, i.e. saturation of primary adsorption sites followed by subsequent filling of the total micropore volume, are clearly reflected by the thermodynamic data.
The Influence of the Calibration Procedure of a Volumetric Adsorption Apparatus on the Form of the Isotherm and its BET Parameters
Authors: Jelinek L. , Dong P. , KováTs E. Sz.
Published: July 2017

An up-to-date piston-operated automatic adsorption apparatus has been tested. Statistical analysis of the results has shown that the adsorbate must be considered as a real gas if a precision of 1% in the adsorption isotherm is to be aimed for at points around 1 bar for gases having a second virial coefficient higher than about 30 cm3/mol. A quadratic calibration is recommended and the influence of operational variables demonstrated on a few examples. Results can be applied, mutatis mutandis, to any volumetric adsorption apparatus. It has then been shown that the generally applied linear calibration procedure gives deformed isotherms, their evaluation resulting in BET surface areas 2–12% lower than those obtained by subtracting the non-adsorbed part of the adsorbate with the quadratic, real gas, calibration curve. Finally, it has been shown that isotherms determined by the gravimetric method are the same as those determined with the real gas calibration and give the same BET surface areas.
Changes in Surface Area, Pore Structure and Density during Formation of High-temperature Chars from Representative U.S. Coals
Authors: White W.E. , Bartholomew C.H. , Hecker W.C. , Smith D.M.
Published: July 2017

Multiple techniques (CO2 and N2 adsorptions, NMR spin relaxation of adsorbed water, He pycnometry and Hg porosimetry) have been combined in a comprehensive study to determine changes in surface area (CO2 and nitrogen), density (solid, particle and bulk), and pore structure (pore size and volume distributions of micro-, meso- and macro-pores) in high-temperature char formation from rank representative U.S. coals of the ANL and PETC Banks (i.e. Beulah Zap, Dietz, Utah Blind Canyon, Pittsburgh No.8 and Pocahontas No.3). Chars were formed at high heating rates in a flat-frame burner (maximum temperature of 1473 K), a process representative of char formation in pulverized coal combustion. Most of the surface area of the coals was found in micropores with radii less than 1.5 nm, while 95% or more of the pore volume in the coals (85% of that in chars) was contained in mesopores less than 20 nm). During the high-temperature formation of char in a flame: (I) CO2 surface areas (involving mainly micropores, rpore < 1.5 nm) increase two- to three-fold, while N2 surface areas (involving mesopores. 1.5 nm < rpore < 20 nm) increase 20–200-fold; (2) solid densities increase about 25% due to graphitization, while particle densities decrease by about a factor of two due to large increases in particle porosity; (3) pore volumes increase 5–10-fold; and (4) total porosities increase three- to four-fold, most of this increase occurring in the macropore range. The larger surface areas and porosities of chars relative to coals may be explained by (i) the removal by pyrolysis of strongly adsorbed molecules or volatile hydrocarbons from micropores and small mesopores that would otherwise hinder access of CO2 and N2 molecules; (ii) the creation of new pores during the restructuring process involved in charification; and (iii) opening up by gasification with oxygen of new pores previously blocked to gas adsorption. The preparation conditions (e.g. atmosphere, heating rate and temperature) greatly affect the physical properties including the surface area, porosity and density of the resulting chars. The degree of carbon burnout is an important correlating factor affecting these properties.
Application of Activated Carbon to Decolouration in the Sugar Industry. Part II. Investigations of Equilibrium and Adsorption Kinetics
Authors: BlasińSki Henryk , Kamionowska Urszula , KaźMierczak Janusz , Pustelnik Anna
Published: July 2017

The adsorption kinetics of the decolouration of technical sugar solutions (thin juice) on activated carbon have been investigated in order to construct a kinetic model which describes internal diffusion in adsorbent granules. It was found that the process is best described by a model including both diffusion in the pores and surface diffusion.
Investigation of Polymer Adsorption on to a Metal Surface by an Optical Method
Authors: Bingkui Wang , Shulin Liu
Published: July 2017

An optical method, i.e. the technique of attenuated total reflection (ATR), has been used for the investigation of the adsorption of poly(methyl methacrylate) (PMMA) and polystyrene (PS) on to a silver surface. This provides a simple and very sensitive method for following the adsorption process and for effecting measurements in situ and in real time. It can be applied to any type of solution and substrate and also to scattering solutions.

The experimental data arising from ATR can be used to calculate the effective thickness d and the complex optical constant ∊ = ∊r + i∊i for the adsorbed polymer film on the Ag surface. By use of the Lorentz–Lorenz relationship, the adsorbance (the amount adsorbed per unit area) was calculated from the effective thickness d and the refractive index of the adsorbed film.

The adsorbance of the polymer (PMMA, PS) with different molecular weights and different solvents has been measured against time. The results satisfy the Langmuir equation more closely than hitherto.
Studies on the Sorption Behaviour of Some Amino Acids on Silica Gel Pretreated with Alkalies in Relation to Chromatography
Authors: Kaur (Miss) Parminder , Mundhara G.L. , Tiwari J.S. , Kar H.S.
Published: July 2017

Silica gel for chromatography has been subjected to chemical pretreatment with aqueous NaOH and KOH solutions. The surface-phase pH, surface area, Na+ and K+ ion content and H+-ion exchange capacity of the samples have been determined. Sorption–desorption studies of the amino acids, l(+)-arginine and l(–)-histidine, were carried out from 90% ethanol solution on substrates whose surface-phase pH was in the range 7.0–11.5. Sorption was found to be pH-dependent, with maximum sorption occurring over the pH range 7.5–10.0. The process was fast (10 min to 24 h) and almost athermic (20–50°C). The desorption efficiency and retarding influence of metallic cations on the adsorption were in the order: Th4+ > Al3+ > Mg2+ > Na+. Elution studies and column chromatography of a few synthetic amino acid mixtures have also been carried out.
Applications of Non-Linear Diffusion Equations to the Kinetics of Water Vapour Adsorption by Polymeric Fibres
Authors: Kats B.M. , Kutarov V.V. , Chagodar A.A.
Published: July 2017

In order to describe the kinetics of water vapour adsorption by polymeric fibres, a numeric experiment has been carried out using the framework of a non-linear diffusion model which takes into account the exponential dependence of the diffusion coefficient on the sorbate concentration in the sorbent. The results show a good correlation between theoretical and experimental kinetic curves for polymolecular adsorption. They also confirm the exponential decrease of the diffusion coefficient with an increase in polymolecular filling.
Catalytic Dehydrogenation and Cracking of Cyclohexane over Ni/Al2O3 Solids
Authors: Sultan E.A. , Ahmad A.S. , El-Shobaky G.A. , Ayad S.
Published: July 2017

The catalytic conversion of cyclohexane over Ni/Al2O3 has been investigated using a microcatalytic pulse technique. The nickel content was varied between 7.9–34.3 wt.% NiO and the reaction temperatures were changed between 240–450°C. The liquids and gases produced were analyzed chromatographically. The results obtained reveal that the cyclohexane underwent both dehydrogenation and cracking reactions producing benzene and light aliphatic hydrocarbons, respectively. The nickel metal acts as the actual active constituent of Ni/Al2O3 catalysts. The selectivity towards the cracking reaction was increased by increasing the amount of nickel, the solids possessing 7.9 wt.% Ni showing no detectable cracking activity at temperatures below 350°C. On the other hand, the selectivity towards benzene formation decreased on increasing the extent of nickel in the various solid catalysts. Although catalysts containing 7.9 wt.% nickel showed the smallest catalytic activity, they exhibited the highest selectivity towards benzene formation.
Texture Properties of Undoped and Na2O-doped V2O5/Al2O3, Catalysts
Authors: El-Nabarawy Th. , Mokhtar M. , El-Shobaky G.A.
Published: July 2017

Pure alumina, V2O5–Al2O3 and Na2O-doped V2O5/Al2O3 samples have been obtained and roasted in air over the temperature range 400–750°C. The textural properties of all the calcination products have been determined from nitrogen adsorption studies at 77 K. The inclusion of V2O5 in alumina modifies the textural characteristics leading to an enhancement of activation at temperatures ≤450°C and to an enhancement of sintering at higher temperatures. Furthermore, AlV2O4 which formed at temperatures below 750°C resulted in a tremendous change in the textural properties. Three types of sintering were detected, i.e. particle-particle adhesion, pore widening and phase change. Doping with Na2O retards sintering and at low calcination temperatures gave solids with higher surface areas compared to undoped samples. This has been attributed to activation brought about by the decomposition of NaNO3 and the evolution of nitrogen oxides.
Adsorption of p-Nitrophenol on Activated Carbon Prepared from Phosphoric Acid-treated Apricot Stone Shells
Authors: Khalil Laila B. , Girgis Badie S.
Published: July 2017

The effect of temperature on the adsorption of p-nitrophenol (PNP) from aqueous solution has been determined at various initial phenol concentrations. Eight activated carbons were tested, being laboratory-prepared from apricot stone shells impregnated with H3PO4 and carbonized at 300–500°C. The adsorption capacity increased as a function of the percentage of activating acid added as well as the temperature of carbonization. The PNP surface areas evaluated were generally lower than the nitrogen BET surface areas due to restricted adsorption inside certain pores. Enthalpies of adsorption of 20–24 kJ/mol were estimated in all cases, except for one carbon which exhibited 'activated', diffusion-controlled adsorption. Greater than 90% desorption was observed at 100 ppm levels of PNP, but this decreased considerably at higher phenol levels.
An Inexpensive Adsorption Technique for the Treatment of Carpet Effluents by Low Cost Materials
Authors: Gupta G.S. , Shukla S.P.
Published: July 2017

The application of adsorption techniques for the treatment of carpet effluents containing mainly Metomega Chrome Orange GL (MCO) using various low-cost materials, i.e. coal, fly ash, china clay and wollastonite, has been tested. In all cases, low initial dye concentration, low temperature and low pH favour the removal process. The maximum uptake of the dye by these materials has been determined at 30°C and a pH of 4.5. The effect of pH on the removal of the said dye has been explained in terms of surface hydroxylation and complexation. Various empirical models have been developed in an attempt to correlate the percentage uptake of dye with the parameters investigated. Dynamic modelling of the dye uptake has been undertaken and found to follow first-order kinetics. The rate constants were determined during the adsorption of the dye under the optimum conditions. Coefficients for mass transfer and intraparticle diffusion were also evaluated in order to explain the mechanism. Langmuir's isotherm was found to be valid. Significant desorption of the dye from the surface of the adsorbents was noted at pH 12.0.
Adsorptive and Membrane-Type Separations: A Bibliographical Update (1994)
Authors: Ray Martin S.
Published: July 2017

This paper provides a bibliography of the 1994 journal literature for adsorptive and membrane-type separations. The references are taken from the 45 most important chemical engineering journals. This paper provides an update to the literature as provide in previous bibliographic papers (Ray 1990a, 1991, 1994, 1995). A bibliography of the chemical engineering journal literature from 1967–88 has been published by the author (Ray 1990b), and can provide access to a wider range of topics. A complete bibliographic listing of the chemical engineering journal literature from 1989 to 1995 (with subsequent six-monthly updates) is available on a CD-ROM database and full details can be obtained from the author.

The papers included here have been divided into the following subject groups: theory; design data; adsorbents; PSA and cyclic systems, and applications; liquid-phase adsorption; ion exchange, chromatography, etc.; membranes; and membrane-type separations.
The Structure of the Electrical Double Layer at the LiChrospher-Type Adsorbent/Aqueous Electrolyte Solution Interface
Authors: Janusz W.
Published: July 2017

The surface charge, adsorption densities of Na+ and Cl− ions and zeta potential at the LiChrospher/NaCl solution interface have been determined as a function of the pH of the solution and the NaCl concentration. The surface ionization and complexation constants have been calculated from potentiometric titration data. Some corrections in the calculation of electrical double layer parameters were made to account for impurities. An attempt to fit the surface complexation model to the surface charge and adsorption of background electrolyte ions at the LiChrospher/NaCl solution interface was made using numerical procedures. The additional adsorption of ions and the interaction of ions in the electrical double layer were considered in an attempt to improve the fit of the standard site binding model to the experimental data.
Controlled Gasification of Carbonaceous Materials in a Water Vapour Atmosphere. Part II. Effect of CaII and FeIII Ions on the Gasification Kinetics
Authors: Grzegorczyk W. , Leboda R.
Published: July 2017

The catalytic activities of calcium(II) and iron(III) ions were studied in the controlled gasification of carbonaceous materials by means of water vapour. The CaII ions were introduced into the carbonaceous materials by ionic exchange as well as by the classical impregnation method. Irrespective of the method of introduction, calcium ions are an effective catalyst for the process, decreasing the activation energy from 185 kJ/mol to 169–164 kJ/mol. Iron(III) ions are not an effective catalyst for gasification by means of water vapour. During the course of this reaction at high water vapour pressure, the FeIII ions change into a non-active form of the stable oxide and do not take part in the process.
Investigation of the Mechanism of Polymer Adsorption on a Metal Oxide/Water Solution Interface
Authors: Chibowski Stanisław
Published: July 2017

The results of investigations of polymer adsorption in dispersed solid/water solutions of a polymer are presented. Poly(vinyl alcohol) (PVA), polyacrylamide (PAM) and poly(acrylic acid) (PAA) were used as polymers and TiO2, Fe2O3, Al2O3 and polystyrene latex as adsorbents. All measurements were conducted with fractionated commercial polymers. Analysis of the experimental and theoretical data obtained proved that of the three kinds of structures created during macromolecule adsorption, i.e. trains, loops and tails, tails play the main role in determining the thickness of the adsorption layer.
The Effect of Fly Ash on Some Surface Characteristics and Microstructure of β-C2S
Authors: Khalil Kh.A. , Amer A.A.
Published: July 2017

The effect of the addition of fly ash (0–15 wt. %) on the surface characteristics of β-C2S and its microstructure was investigated using nitrogen adsorption at −196°C together with scanning electron microscope (SEM) techniques. The results obtained revealed that the addition of fly ash up to 5 wt. % increased the specific surface area by 32% followed by a decrease of 34% when the fly ash content was increased up to 15 wt. %. SEM investigation showed that the hydrates produced form an outer shell which coats the fly ash particles.
Interaction of Water and other Polar Substances with Hydrophilic Centres on the Surface of Hydrophobic Adsorbents
Authors: Tarasevich Yu.I. , Zhukova A.I. , Aksenenko E.V. , Bondarenko S.V.
Published: July 2017

The adsorption of water and other polar substances on to the surface of graphitized carbon black and macroporous silica modified by polymethylhydride silicone has been studied using gas chromatography. The adsorption heat values of the substances studied were determined and the concentration of surface hydrophilic centres estimated. Conclusions have been drawn concerning the number of water molecules adsorbed on to hydrophilic centres at low surface occupation values. In the case of water adsorption on the graphitized carbon black surface, the chromatographic data for the adsorption heat have been compared with the energy of water molecule interaction with the surface clusters modelling the micropores existing on the basal surface of carbon black particles as calculated using quantum chemical methods.
Adsorption/Oxidation of CH3OH on V2O5. A Theoretical and Experimental Study
Authors: Sambeth Jorge , Juan Alfredo , Gambaro Luis , Thomas Horacio
Published: July 2017

The adsorption/oxidation of CH3OH on V2O5 was studied in previous work by mass spectrometric analysis of the reaction atmosphere, and by measuring the electrical properties (Hall effect) and total pressure of the system. Such data allowed a reaction pathway to be proposed.

In the present work, the variations in the surface oxidation number have been calculated via balances in the C and H atoms in the reaction atmosphere and models of the (010) plane of V2O5 and of CH3OH have also been utilized to find energetically favourable sites for the adsorption of CH3OH and its subsequent oxidation to H2CO. For this purpose, the variation in the total energy of the system was computed by Extended Hückel-type calculations (ASED, Atom Superposition and Electron Delocalization).

From such experimental results, it was deduced that the H atoms are removed by the network oxygens and that methanol is adsorbed as the methoxy group. Such removal of H atoms has two consequences: high surface hydroxylation and surface reduction [V(5+) → V(4+)].

In support of these suggestions, the theoretical results have confirmed both the removal of H atoms and methoxy group formation, and have also revealed two possible adsorption sites for CH3OH on V2O5: the terminal oxygens (V=O) and the network bridging oxygens (V-O-V).
Variation in the Adsorption of Lead(II) by a Range of Electrolytic Manganese Dioxides: Chemometric Examination of Correlation with Physical Properties
Authors: Dahal Madhav P. , Lawrance Geoffrey A. , Maeder Marcel
Published: July 2017

The adsorption of lead(II) by a range of ‘boutique’ electrolytic manganese dioxide (EMD) samples which differ in a range of physical properties has been followed at pH 5, 20°C and an ionic strength of 0.5, employing a wide range of initial lead ion concentrations from 5 × 10−5 mol/dm3 to 5 × 10−2 mol/dm3. Adsorption isotherms all fitted quite well to a simple Langmuir adsorption equation. The Langmuir parameters vary significantly for the different samples and good correlations between them and some physical properties (% water content, open circuit voltage and average crystallite size) are apparent. Further, Principal Component Regression (PCR) reveals excellent correlations between the lead(II) adsorption isotherms and some of the physical properties (water content, average crystallite size, density, total pore volume, electric conductivity, porosity, etc). A qualitative understanding of the relationship between the isotherms and the physical properties can be achieved. Adsorption of lead on partially chemically reduced EMD samples falls as the degree of reduction increases, associated with a drop in available hydrolysable surface groups with increasing degree of reduction.
Adsorption of Different Surfactants on Kaolinite
Authors: Atia A.A. , Radwan N.R.E.
Published: July 2017

The adsorption of anionic, cationic and non-ionic surfactants on kaolinite has been investigated. Anionic surfactants are widely used in enhanced oil recovery. The lower the adsorption on the oil-bearing rock, the higher the advantage of the surfactant to be used. Whilst the adsorption of anionic and non-ionic surfactants are negligible, that of cationic surfactants is relatively high. For this reason, the use of cationic reagents in the enhanced oil recovery is not recommended. The adsorption of cationic surfactants was found to follow an ion-exchange mechanism, while that of anionic and non-ionic surfactants proceeded through electrostatic attraction and precipitation.
Diffusion of 1, 2-Dichloropropane in Particles of Activated Carbon
Authors: Bobok Daniel , Besedová Eva
Published: July 2017

The diffusion of 1, 2-dichloropropane in activated carbon particles was studied during adsorption and desorption. Measurements were performed in adsorbers with a bed height equal to the diameter of the activated carbon particles, using air as the carrier gas. Based on the assumption that the porous medium was quasi-homogeneous, effective diffusion coefficients were calculated from the experimental data for two adsorption stages and one desorption stage. Although the effective diffusion coefficient, as calculated from the desorption data, agreed to within an order of magnitude with the values obtained from the adsorption data, its absolute value was significantly lower. Comparison of the values for the effective diffusion coefficients measured experimentally with those calculated by means of a model showed that molecular diffusion rather than Knudsen diffusion occurred during the transport of 1, 2-dichloropropane in activated carbon particles
Synthetic Carbon Derived from Polyimide
Authors: Puziy A.M. , Matynia T. , Gawdzik B. , Poddubnaya O.P.
Published: July 2017

Synthetic carbon was obtained from the porous copolymer of 4, 4'-bis(maleimidodiphenyl)methane and styrene by carbonization in inert and methane atmospheres. The samples were characterized by nitrogen adsorption and mercury intrusion using BET, αs, DR and Kelvin analysis. It was shown that carbonization in an inert atmosphere results in the formation of microporous and mesoporous carbon, while heat treatment in an atmosphere of methane decreases the porosity due to the deposition of pyrolytic carbon in small pores (R < 2–3 nm).
Kinetic Model for Lead(II) Sorption on to Peat
Authors: Ho Y.S. , McKay G.
Published: July 2017

The kinetics of lead sorption on to peat have been investigated. The batch sorption model, based on the assumption of a pseudo-second order mechanism, has been developed to predict the rate constant of sorption, the equilibrium capacity and initial sorption rate with the effect of initial lead(II) concentration, peat particle size and temperature. An equilibrium capacity of sorption has been evaluated with the pseudo-second order rate equation. In addition, an activation energy of sorption has also been determined based on the pseudo-second order rate constants.
Sorption of Semi-Volatile Organic Compounds by Bottom and Fly Ashes Using HPLC
Authors: Daifullah Abd. El-Hakim , Gad Hamdy
Published: July 2017

The adsorption of phenolic compounds on a mixture of bottom and fly ashes has been investigated. Thus, the effect of molecular weight and molecular configuration on the adsorption of phenol (Ph), m-cresol ( m-Cr), p-cresol ( p-Cr), 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP) from aqueous solution have been determined. The thermodynamic parameters for the adsorption of 2-NP and 4-NP have been calculated on the basis of Everett's isotherm equation. Batch experiments were conducted to produce isotherms for single-component, two-component and four-component systems. For this purpose, high-performance liquid chromatography was used. It was found that the ultimate capacity of the adsorbent is considerably less than that predicted from summing the single-component data; this has been attributed to increased competition for adsorption sites.
Estimation of the Surface Properties of Unmodifed and Strongly Oxidized Active Carbons on the Basis of Water Vapour Adsorption Isotherms
Authors: Choma J. , Jaroniec M.
Published: July 2017

Water vapour adsorption isotherms were measured for a series of commercial active carbons and one carbon black oxidized with concentrated nitric acid at its boiling temperature. A comparative analysis of the surface properties of the unmodified and strongly oxidized active carbons was performed on the basis of the adsorption potential distributions (APDs) calculated from these adsorption isotherms. It was shown that the APDs for oxidized carbons exhibit some extra details (e.g., peaks) in the range of high adsorption potentials which can be assigned to interactions of water molecules with oxygen surface groups formed during the oxidation process. This is especially visible for oxidized carbon black. The observed sensitivity of the APDs obtained from water vapour adsorption isotherms make them attractive functions for monitoring the surface changes in active carbons due to their oxidation.
Dubinin's Theory for the Volume Filling of Micropores: An Historical Approach
Authors: Stoeckli F.
Published: July 2017

The origin and development of Dubinin's theory are presented within their historical context. The emphasis is put on the author's long-standing collaboration with M.M. Dubinin. It is shown how the main correlations between the structural properties of active carbons and the parameters of the DR and DA equations have been established and crosschecked. As shown recently, the adsorption of water by microporous carbons, corresponding to a type V isotherm, can also be described by the equation of Dubinin and Astakhov. This new approach includes the enthalpy of immersion into water, a thermodynamic consequence of Dubinin's theory.
Application of the Dubinin–Astakhov Equation to the Study of the Geometric Structure, Energetic Surface Heterogeneity and Surface Topography of Carbonaceous Adsorbents
Authors: Rudziński W. , Nieszporek K. , Dabrowski A.
Published: July 2017

The new theoretical approach to multisite-occupancy adsorption on heterogeneous surfaces, developed recently by Rudziński and Everett, is generalized for the case of adsorption systems characterized by non-Gaussian adsorption energy distributions. Attention is focused on the adsorption energy distribution which, in the case of one-site-occupancy adsorption, leads to the Dubinin–Astakhov isotherm equation. In effect, a generalized form of that isotherm equation is developed for the common case of multisite-occupancy adorption in actual adsorption systems. The generalized equation is sensitive to surface topography; hence, fitting it to experimental adsorption isotherms creates a chance to study the surface topography of carbonaceous surfaces. An example of such computer exercises is reported here before a more systematic study is published.
On the Dubinin-Serpinski Equation
Authors: Carrott P.J.M.
Published: July 2017

An analysis is presented of the assumptions involved in both the derivation and practical application of the Dubinin–Serpinski (DS) equation. It is concluded that, although the model is very simple, it manages to take into account many of the principal factors involved in the formation of an adsorbed water phase on carbon surfaces. Furthermore, although only a relatively small amount of work has been published so far on the application of the DS equation, those results which are available suggest that the equation holds great promise for the characterisation of both the functionality and microstructure of carbon adsorbents. It is pointed out, however, that there is an urgent need for more independent studies and a number of suggestions for future work are given.
Liquid-phase Adsorption of Bulk Ethanol–Water Mixtures by Alumina
Authors: Rao M.B. , Sircar S.
Published: July 2017

Separation of ethanol–water liquid mixtures can be carried out by selective adsorption of water on activated alumina. The moderate selectivity and heat of adsorption of water on the alumina permits easier and less energy intensive desorption of the adsorbed water. Experimental binary surface excess isotherms, liquid-phase adsorption kinetics and column dynamics for the adsorption of bulk water–ethanol mixtures on Alcoa H152 alumina are reported. Model analyses of the data are carried out to quantify the selectivity of adsorption, adsorptive mass-transfer coefficients and the properties of the mass-transfer zones in adsorption columns.
Elution Adsorption Dynamics of Organic Substances on Carbon Adsorbents
Authors: Polyakov N.S. , Larin A.V. , Goubkina M.L.
Published: July 2017

Breakthrough curves of CF3Cl on carbon black and of cyclo-hexane on active charcoal have been measured under elution adsorption dynamic conditions. For linear and non-linear adsorption dynamic modes, the experimental data and theoretical results calculated according to the layer of equilibrium adsorption (LEA) model closely coincide.
Effect of Catalytic Gasification of Active Carbon from Plum Stones on its Mesoporous Structure
Authors: Leboda R. , Grzegorczyk W. , Lodyga A. , Dabrowski A.
Published: July 2017

The possibilities of the development of a mesoporous structure during gasification of carbonaceous material with water vapour in the presence of a calcium(II) catalyst are demonstrated. Investigations have been carried out on active carbon prepared from plum stones. For comparison, the same experiments in the absence of the catalyst were also made. The characteristics of the micro- and meso-porous structures of the adsorbents have been determined from the adsorption–desorption isotherms of nitrogen. The data have been submitted to treatment from the BET, Harkins–Jura, Sing as well as Derjaguin, Broeckhoff, de Boer and Dubinin equations. The texture of the adsorbent particles has been studied by means of scanning electron microscopy. The kinetics of gasification of the carbon adsorbent in the presence and absence of catalyst has also been studied. In addition, samples of the prepared carbon adsorbents were examined by X-ray diffraction.
A New Method of Calculating Kováts Retention Indices for Substances Chromatographed on Carbon Adsorbents
Authors: Grajek H. , Witkiewicz Z. , Jankowska H. , Światkowski A.
Published: July 2017

The net retention volumes relative to zero adsorbate coverage of adsorbent at 273.2 K, i.e. V0S(273), have been determined on two active carbons with well-developed micropore structures. Kováts retention indices have been calculated on the basis of these net retention volumes using two methods. The first involved the substitution of the net retention volumes in the Kováts equation. The second method, which is a new method, involved a description of the net retention volumes by the function log V0S(273) = f(Tc), where Tc is the column temperature, followed by the calculation of the average values for the net retention volumes using the best-fit curve. Kováts retention indices were then calculated from the average values of the net retention volumes. A comparison of the results obtained indicates that the new method appears to yield better values. The Kováts retention indices obtained via both methods were also calculated using a quadratic equation.
Adsorption Concentration of Platinum Metals by Clinoptilolite
Authors: Vrublevs'ka T. Ya. , Vrons'ka L.V. , Korkuna O.Ya. , Matviychouk N.M.
Published: July 2017

Ruthenium(IV) and palladium(II) adsorption from aqueous solutions on to Transcarpathian clinoptilolite has been studied under dynamic conditions. The optimum conditions for ruthenium(IV) adsorption from aqueous solutions have been established as follows: pH = 3.5–4.5 or 9.0–11.0; radius of adsorbent particles, 0.200–0.355 mm; and velocity of solution passing through the adsorbent, 3 mm/min. For palladium adsorption from aqueous nitric acid (pH = 4.0) and ammonia (pH = 11.5) solutions, the optimum radius of the adsorbent particles was in the 0.355–0.500 mm range. Desorption of RuIV and PdII was performed using 6 M hydrochloric acid. The degree of ruthenium(IV) extraction under optimum conditions was 95% and for palladium(II) extraction from nitric acid and ammonia solutions the corresponding values were 81.5% and 96.8%, respectively.
Removal of Some Surfactants from Dilute Aqueous Solutions Using Charcoal
Authors: Saleh Mahmoud M. , Atia Asem A.
Published: July 2017

The efficiency of charcoal in removing anionic, cationic and non-ionic surfactants from their aqueous solutions was studied. Measurements were performed on Triton (TX-100), cetylpyridinium chloride (CPC) and dodecylbenzene sulphonate (DBS) as examples of non-ionic, cationic and anionic surfactants, respectively. Removal efficiencies of up to 90% were achieved for all the surfactants studied. In addition, synergistic interaction between the non-ionic and either cationic or anionic surfactants was demonstrated. The extent of adsorption of non-ionic surfactants was improved by the addition of either the anionic or cationic surfactants. Complete adsorption isotherms were obtained for the three surfactants at 28°C. The lateral interaction coefficient and the standard free energy of adsorption were calculated from an analysis of the adsorption data according to the modified Frumkin isotherm.
Economy, Society and Space: Books in 1983
Authors: Forbes D K , Thrift N J , Williams P
Published: July 2017

This is the second in a series of annual reports on books likely to be of interest to readers of Society and Space. Once again, the report is synoptic. The welter of literature of direct or tangential relevance that appears each year defeats any attempt to be all-encompassing. This year the report is divided into six sections, some of which are carried over from last year. The six sections are “Economy”, “The State”, “Third World”, “Housing”, “Class and Civil Society” and “Methodology and Social Theory”.
Effect of Testing Temperature on the Energy Absorption Behavior of Carbon Fiber/PEEK Composite Tubes
Authors: Hamada H. , Ramakrishna S. , Sato H.
Published: July 2017

The primary objective was to study the effect of testing temperature on the energy absorption characteristics of carbon/PEEK composite tubes. Composite tubes with 0° fiber architecture were tested at different temperatures in the range from -100°C to 150°C. Tubes tested at -100°C and -80°C failed catastrophically by longitudinal cracking parallel to fibers and splitting of tube wall into segments. This was attributed to the reduced fracture toughness at these low temperatures. Composite tubes tested at temperatures above -60°C crushed progressively by the splaying mode. The energy absorption capability increased with increasing temperature from -60°C to -10°C and then decreased with further increase of temperature. A maximum energy absorption capability of 245 kJ/kg was displayed by the tubes tested at -10°C. This variation of energy absorption was attributed to the changes in morphological features of the crush zone and the mechanical properties of composite material with temperature.
Impact Response of Doubly Curved Laminated Composite Shells Using Higher-Order Shear Deformation Theories
Authors: Maiti Dipak K. , Sinha P. K.
Published: July 2017

In the present investigation the higher-order and conventional first-order shear deformation theories are used to study the impact response of doubly curved laminated composite shells. The formulation is based on the Donnell's shallow shell theory. Nine noded Lagrangian elements are used for the finite element formulation. Modified Hertzian contact law is used to calculate the contact force. The results obtained from the present investigation are compared with those existed in the open literature. Numerical results are presented to study the effects of span to thickness ratio, boundary condition, impact point, stacking sequence and velocity of the impactor for cylindrical and spherical shells.
Elastic Properties of Polymer Systems Reinforced with Short Organic Fibers
Authors: Kanaun S. K. , Dogopolsky A. A. , Vazquez-Polo G. , Castano V. M.
Published: July 2017

This paper addresses the experimental and theoretical investigations of mechanical properties of polymer resins reinforced with natural fibers. These materials have potentially a wide area of applications and relatively low cost because they are made of inexpensive resins and fibers obtained from plants available in the Mexican desert. We present the results of experimental investigations of elastic properties and strength of composites based on three types of polymer resins reinforced with natural fibers of Palma Zamandoca. Theoretical analysis of effective elastic and strength properties of short-fiber matrix composites is given based on the advanced self-consistent scheme permitting to account for interactions between fibers. The method utilizes the idea of introducing the effective strain field which affects every inclusions in the composite. In distinction to the traditional forms of the effective (i.e., self-consistent) field method we assume that the effective field is not constant and the same for all fibers but rather depends on the orientation of each of them. This allows to take into account the characteristics of the spatial distributions of fibers in the volume of composite. The scheme utilizes the asymptotic solution of elastic problem for rigid cylindrical bar. The results of theoretical analysis are compared with extensive experimental data on composites with natural fibers manufactured and tested by the authors as well as with the data for composites with inorganic fibers (e.g., glass and carbon fibers) available in literature.
Stress Field in Coated Continuous Fiber-Reinforced Polymeric Composite Due to Hygrothermal Loading
Authors: Upadhyay P. C. , Murthy K. Guru , Lyons D. W.
Published: July 2017

Based on a four phase model of the composite, effects of fiber-matrix interphase (coating) on the stresses developed in different constituent phases due to hygrothermal loadings are evaluated. Interphase coating with high, low and the same modulus as that of the matrix have been considered. Obtained stresses, considering degradation in properties of the coating and the matrix due to moisture absorption and temperature rise, have been compared with the corresponding values furnished without properties degradation. Graphite being transversely isotropic and having opposite nature of thermal expansion coefficients in the longitudinal and transverse directions, the bulk of the results are given for the graphite/epoxy composite. The importance of the consideration of coating as a separate phase with its appropriate properties on the stress concentrations in different constituent phases is clearly brought out. It is also suggested that due accounting should be made for the changes in the properties of the matrix and the coating, caused by hygrothermal conditioning, otherwise the stress estimates could be quite misleading and erroneous. Effects of coating thickness and fiber volume fraction are also discussed.
Capillary Impregnation of Aligned Fibrous Beds: Experiments and Model
Authors: Batch Gibson L. , Chen Yung-Tin , Macoskot Christopher W.
Published: July 2017

Capillary flow affects the amount of air entrapped between fiber reinforced composites during the impregnation. This paper investigates the permeability of aligned fiber bundles by capillary flow in both longitudinal and transverse directions. Experiments measure capillary flow by the rate of weight gain of fiber-filled tubes having one end in contact with a fluid at atmospheric pressure. The driving force for this flow is capillary pressure only; no external driving pressure is applied during impregnation. Permeabilities obtained under these conditions are slightly lower than those measured under conditions of positive external pressure. The Kozeny constant for longitudinal flow are found to be 1.06, and for transverse flow to be about 8.

A simple model is derived to illustrate the role of capillary flow along fiber reinforcements during wetting. While capillary flow is insignificant with high injection rates, it is significant at low injection rates. The model indicates that for a specified fiber volume fraction in the fiber bundle, there exists a unique injection speed in which the bulk fluid flow front matches the capillary flow front inside the bundle. Injection at that speed is usually too slow to be practical, but it would substantially reduce the void content in fiber bundles after impregnation. At high injection rates, the model indicates the possible trapping of air inside fiber tows due to the capillary flow lagging behind the bulk flow.
On the Dynamics of Gas-Assisted Injection Molding Process
Authors: Chang Rong-Yeu , Tsai Ming-Horn , Hsu Chia-Hsiang
Published: July 2017

Gas-assisted injection molding offers a cost effective means of production of hollow plastic parts and a solution to the problems associated with conventional injection molding, such as warpage and sink marks. In this paper, a computer-aided engineering tool is developed and applied to the analysis of this process. Dynamic animation of the analysis result is offered in order to mimic the dynamics of polymer melt, gas injection, and penetration behavior during the filling and gas-packing stages. Also, the influences of processing conditions, mold design and material properties on the molding behavior of a commercial production mold is investigated in order to establish useful design guidelines.
Development of a Mathematical Model for the Calculation of the Pressure Drop in Extrusion Dies
Authors: Lang U. , Michaeli W.
Published: July 2017

Analytical approaches for calculating the pressure drop in extrusion dies are limited because they are only applicable in ideal flow channel geometries.

In finite element calculations the pressure drop in different flow channels was determined. Parallel the cross section of those geometries was calculated, transformed into the ideal form of a slit or circle and analytical calculations were done. From the results a correction function was derived. This enables realistic pressure drop calculation by applying simple analytical equations.
Flow of Polymer Melts in Planeand Axi-Symmetric Converging Dies
Authors: Lauridsen Carsten L. , Kiaer Erik M. , Haudrum Jan
Published: July 2017

The extensional flow has considerable influence on the pressure loss in converging flows, which are present in both extrusion and injection moulding. Both plane-and axi-symmetric converging flows have been studied with LDPE, HDPE and PS. The transient extensional viscosities are determined in all cases. The extensional viscous description used is the one proposed by Cogswell [3].

The extensional viscosities in the two different flow fields are compared. The planesymmetric extensional viscosity is found to be larger than the axi-symmetric for the HDPE melt. The two viscosities are comparable for the LDPE and the PS melts.

Furthermore, the pressure losses are characterized with the Deborah number in which the characteristic time of the material is shear rate dependent and the characteristic time of the flow is Hencky strain rate dependent.
Jute Sack Cloth Reinforced Polypropylene Composites: Mechanical and Sorption Studies
Authors: Harikumar K. R. , Joseph Kuruvilla , Thomas Sabu
Published: July 2017

Composite materials were fabricated using jute and polypropylene sacks by compression molding. Different types of composites were fabricated by varying the number of jute layers, number of polypropylene layers and the mode of combination of jute and polypropylene layers keeping the total number of layers a constant. It was found that as the number of polypropylene layers increases, the tensile strength, tear strength and modulus increased, but the elongation at break and equilibrium water uptake were found to be decreased. Also, when the number of jute layers increases, by keeping the number of polypropylene layers constant, generally failure properties decreased but an increased water uptake was observed. The influence of various constructions on the properties was analysed by changing the mode of combination of jute and polypropylene layers. In these experiments, the total number of layers were fixed a con stant. It was found that the preferred combination is one with jute as core layer and polypropylene as skin layers. Scanning electron microscopy was used to analyse the failure surface morphology of the composites. Finally value added product was fabricated using selected composites.
The political struggle around Orwell's stapler
Authors: Seddon Mark
Published: July 2017

The meekly paper, Tribune, is now one of the few remaining left-wing radical newspapers left in existence. There is, of course, the New Statesman as well, but no longer a national daily or Sunday newspaper of the old left unless one includes the now diminished Morning Star in that category. Tribune tries to fill that gap and the paper's Editor sets out, below, the trials and tribulations of doing so on very limited resources....
Book Reviews: Dont'take the fun out of libel law
Authors: Bindman Geoffrey
Published: July 2017

Britain's libel law is among the most contentious of all in our legal system. A recent book by David Hooper, a leading libel lawyer, has examined the whole scene with the literary brush of the true expert. Below is an appreciation of Hooper's book by another distinguished lawyer in the same field who bimself makes a case for fresh thinking on libel law, but also warns .....
The influence of ethanol on long-term effects of dibutyltin dichloride (DBTC) in pancreas and liver of rats
Authors: Merkord J , Weber H , Jonas L , Nizze H , Hennighausen G
Published: July 2017

The present study was done to determine the additional influence of daily ethanol intake (15% in drinking water ad libitum) on long-term toxic effects of a single administration of dibutyltin dichloride (DBTC, 8 mg/kg b.w. i.v.) in pancreas and liver of rats. Pathohistological changes in pancreas, bile duct and liver as well as pathobiochemical parameters of pancreatitis (amylase and lipase activity), liver lesions (alkaline phosphatase activity and bilirubin) and fibrosis (hydroxyproline and hyaluronic acid) were measured 1 day and 1 to 24 weeks after DBTC- and DBTC/ethanol administration. DBTC alone induced in rats an acute interstitial pancreatitis as well as acute bile duct and liver lesions in the early experimental phase. Later on, the acute inflammatory processes in pancreas and liver took a chronic course resulting in pancreatic fibrosis and liver cirrhosis. Ethanol increased the toxic effects of DBTC on pancreas and liver during the acute and chronic course. In the acute phase lasting 1 day to 2 weeks, ethanol enhanced the DBTC toxicity on acinar cell and bilio-pancreatic duct epithelium as well as the formation of obstructive ductal plugs by necrotic cell debris. The obstruction and cholestasis in the DBTC/ethanol-group were significantly stronger as in the DBTC-group. The significant increase of hydroxyproline in urine and hyaluronic acid in serum of the DBTC/ethanol treated rats after 12 to 24 weeks was connected with a more severe chronic inflammatory fibrosis in pancreas and liver in comparison to the DBTC-treated group.