Mohamad Asif

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Effect of Temperature and Electrolytic Concentration on Density and Viscosity of Ethanol-Water Mixed Solvent Systems

International Journal of Scientific Research in Science and Technology

The density and Viscosity of Ethanol-Water mixed solvent systems (5%, 10%, 20% ,40% v/v ) has bee... more The density and Viscosity of Ethanol-Water mixed solvent systems (5%, 10%, 20% ,40% v/v ) has been determined at 298,303,308 and 313 K. The same parameters has been determined for the KCl-Ethanol-Water mixture (2%, 4%, 6%, 8%, 10% w/v)The results obtained from these determinations were discussed. The effect of temperature and KCl electrolyte on density and viscosity of mixed solvent systems and mixture has been studied. The increase in temperature of mixed solvent system results in decrease in density and Viscosity. But with the addition of KCl electrolyte in mixed solvent system results in increase in density and viscosity at constant temperature but the same parameters decrease when temperature increases. The variation of these parameters is due to solute-solvent and solvent-solvent interaction.

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Significance and cost effectiveness of pre-operative routine laboratory investigations in young healthy patients undergoing elective ear, nose & throat surgery

Journal of Ayub Medical College, Abbottabad : JAMC

Pre-operative preparation is an important component of surgical workup. Adequate clinical assessm... more Pre-operative preparation is an important component of surgical workup. Adequate clinical assessment to determine fitness for anaesthesia and surgery and to outrule possibilities of existing disease or risk factors against the procedure would suffice in elective surgery on healthy young patients. Still routine investigations are carried out following a protocol, that does not offer added benefit and is not cost effective. We evaluated one hundred and fifty young healthy patients planned for elective surgery, to compare adequate clinical assessment with results of routine investigations in such patients, in terms of significance and cost effectiveness. Significant co-relation was demonstrated between clinical assessment and routine investigations. Only 03 abnormal results were reported following 600 laboratory investigations on 150 patients. Thorough clinical assessment is mandatory for successful outcome of surgery. There is significant co-relation with routine investigations in ele...

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Clinicohistological pattern of ovarian tumours in Peshawar region

Journal of Ayub Medical College, Abbottabad : JAMC

Ovarian tumours are one of the major health problems confronting the general practitioners in gen... more Ovarian tumours are one of the major health problems confronting the general practitioners in general and gynaecologists in particular. Ovarian tumours may either be asymptomatic, found on the routine ultrasound examination or symptoms may be vague till the patient has an acute emergency like torsion or rupture of a benign cyst. The worst is late presentation of a malignant ovarian tumour. There is marked variation in the presentation of the tumour as well as in histological types. This study was undertaken to analyse modes of presentation and various histopathological patterns of ovarian tumours. This study was conducted from 1st January, 2002 to 31st December, 2002, in Gynaecology 'A' Unit, Lady Reading Hospital (LRH) Peshawar. After admitting patients with ovarian tumours a detailed case history was taken followed by thorough clinical examination. All the relevant details were recorded using the questionnaire. Patients were investigated after performing various surgical p...

Distribution of PLATINUM.GROUP Elements in the Niouelandn Layered Mafic-Ultramafic Intrusion, Brazil: Implications with Respect to Exploration

The study of the distribution of PCE, Au, Ni, Cu, Co, and S in the Proterozoic NiquelAndia mafic-... more The study of the distribution of PCE, Au, Ni, Cu, Co, and S in the Proterozoic NiquelAndia mafic-ultramafic layered intru- sion (Brazil), 65 km long and 35 km wide, shows the existence of two distinct stratigraphic zones of contrasting PGE content. The Ultramafic Unit and the lowermost part of the Central Mafic Unit have relatively high PGE contents, whereas all

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Role of hypertension, diabetes, obesity, and race in the development of symptomatic myocardial dysfunction in a predominantly minority population with normal coronary arteries

American Heart Journal, 2000

Background Hypertension, diabetes, and obesity have been reported as risk factors for both vascul... more Background Hypertension, diabetes, and obesity have been reported as risk factors for both vascular and myocardial disease. Myocardial disease may be manifest as systolic or diastolic dysfunction. The development of coronary artery disease frequently obscures or confounds the myocardial disease. Our purpose was to study the effect of these risk factors and race on the frequency and severity of myocardial

Minimum fluidization velocity and defluidization behavior of binary-solid liquid-fluidized beds

Powder Technology, 2002

The minimum fluidization behavior of five different binary-solid systems with a wide range of com... more The minimum fluidization behavior of five different binary-solid systems with a wide range of composition is experimentally investigated by carrying out slow defluidization of an initially fluidized bed. The size ratios of these binaries vary from 4 to 10 while their buoyed-density ratios vary from 0.22 to 0.52 such that their larger components are lighter and smaller ones are denser. The difference in the physical properties of the two constituent solid phases of the fluidized bed is found to strongly influence the evolution of the packing structure, and consequently the minimum fluidization velocity during the slow defluidization process. For binaries with the same size ratio, segregation increases with the decrease in their buoyed-density ratios. On the other hand, even for binaries with large difference in their densities, increasing the size ratio enhances the mixing. Depending upon the composition of the bed, a completely mixed defluidized structure sometimes develops for high size-ratio binaries. Finally, a simple correlation is proposed that can better describe the present minimum fluidization velocity data than other existing correlations.

$For beds with composition, X1, as high as 0.6 and so long as the liquid velocity was close to the Um, of the PET, a pure component layer of the sand was seen developing in the lower zone of the bed with occasional straying of the PET from the upper mixed layer consisting of PET and sand into the lower layer of pure sand. As the liquid velocity was gradually decreased, the lower interface of the upper mixed layer started to stabilize and became more distinct. At this stage, the sand from the lower mono-component layer appeared moving into the upper mixed layer where both components apparently developed uniform concentration. The motion of the sand through the interstices of the PET As the fraction X, was increased to 0.75, its initial defluidization behavior was similar to what has been dis-$

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Epidemiologic association between antibody titres against bovine virus diarrhoea virus, rinderpest disease virus and infectious bovine rhinotracheitis virus in a buffalo herd

Tropical Animal Health and Production, 1996

The association between antibody titres against bovine virus diarrhoea virus (BVDV), infectious b... more The association between antibody titres against bovine virus diarrhoea virus (BVDV), infectious bovine rhinotracheitis virus (IBRV) and rinderpest disease virus (RPDV) in buffaloes was investigated in a cross-sectional study. Thirty-six lactating buffaloes from a herd in Landhi Cattle Colony, Karachi were bled and serum samples subjected to a micro-neutralisation test at the Plum Island Animal Disease Center, USA, to categorise each buffalo either as positive or negative against each of 3 viral antigens. Log-linear analysis was used to evaluate the association among 3 categorical variables. The &quot;best-fitting&quot; log-linear model was the model of complete independence. This model includes all 3 main effects (BVDV, IBRV, RPDV), suggesting that the seropositivity of buffaloes against these viral antigens tended to occur independently. Estimates of parameters of the model showed that the proportion of buffaloes seropositive (97.2%) to RPDV antigen tended to be higher than expected, whereas the proportion of BVDV seropositive (30.6%) and IBRV seropositive (16.7%) buffaloes tended to be smaller than expected.

Elimination of reagent blank problems in the fire-assay pre-concentration of the platinum group elements and gold with a nickel sulphide bead of less than one gram mass

The Analyst, 1989

... Mohammad Asif and Susan J. Parry Imperial College Reactor Centre, Silwood Park, Ascot, Berksh... more

Study of the digestion of chromite during nickel sulphide fire assay for the platinum group elements and gold

The Analyst, 1991

Study of the Digestion of Chromite During Nickel Sulphide Fire Assay for the Platinum Group Eleme... more

Volume contraction behaviour of binary solid–liquid fluidized beds

Powder Technology, 2004

Contrary to the widely held notion that the total bed height of a binary solid fluidized bed will... more Contrary to the widely held notion that the total bed height of a binary solid fluidized bed will be the sum of heights of the two individual mono-component beds fluidized at the same velocity, significant negative deviations have been observed in our experimental investigation. The negative deviations, signifying a contraction of the total volume of the binary solid fluidized bed, could sometimes be as high as 25% of the actual volume. The volume contraction has been found to depend mainly upon the degree of solids mixing prevailing in the bed irrespective of whether it is fully fluidized or not. The composition of the binary solid fluidized was another important factor that influenced the contraction behaviour of the bed besides the size ratio of the two constituent solid species of the binary present in the bed.

format_quoteExperimental results show volume contraction in binary solid fluidized beds, sometimes up to 25% lower than predicted values under equal conditions.format_quote

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The complete segregation model for a liquid fluidized bed: formulation and related issues

Powder Technology, 2004

The complete segregation model of Gibilaro et al. [Chem. Eng. Sci. 41 (1986) 379] has been widely... more The complete segregation model of Gibilaro et al. [Chem. Eng. Sci. 41 (1986) 379] has been widely used to predict the layer-inversion phenomenon in a binary solid-liquid fluidized bed. Important features of the model have been analyzed in this paper. Simplifications are proposed to reduce the original two-dimensional optimization problem to mainly a single implicit algebraic equation. A hybrid scheme using a combination of both property-averaging scheme as well as the serial model for evaluating the bed void fraction apparently improves the model predictions. Finally, it has been shown that a straightforward extension of the model from the binary solid to the ternary solid case is generally not tenable.

format_quoteThe hybrid approach significantly improved predictive accuracy for PET-Sand and PET-Glass systems, reducing mean percentage deviations.format_quote

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Predicting binary-solid fluidized bed behavior using averaging approaches

Powder Technology, 2002

The present study reports new experimental data on the expansion as well as the layer-inversion b... more The present study reports new experimental data on the expansion as well as the layer-inversion behavior of liquid-fluidized beds containing two particle species with almost 10-fold difference in the size and a significant difference in the density. The packing models, which are generally used for predicting the porosity of the packing of particle mixtures, are used here to describe the expansion and the phenomenon of the layer-inversion. Predictions of different averaging models, including the property-averaging model, the serial model, and various packing models, are compared with the present data as well as the layer-inversion data reported in the literature. The overall predictive capability of packing models is found to be superior.

$Fig. 1. Expansion behavior of mono-component fluidized beds of polyethylene terephthalate (PET) resin and sand and their parameters of Richardson and Zak correlation. The test section of the fluidized bed consisted of a transparent perspex column of 60-mm internal diameter and 1.5-m length. The distributor was a 9-mm-thick perfo- rated plate with 2-mm holes drilled on a square pitch and 4% fractional open area. This configuration gives about 1.3 The fluidization behavior of particle samples was indi- vidually examined using water at 20 °C. Table 1 reports parameters U;, and n which were obtained by fitting the$

$Fig. 2. (a) Expansion behavior of binary-solid fluidized bed for composition X\=0.41. (b) Expansion behavior of binary-solid fluidized bed for composition X=0.60. (c) Expansion behavior of binary-solid fluidized bed for composition X;=0.86.$

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A simple predictive model of layer inversion in binary solid–liquid fluidized beds

Journal of Chemical Technology & Biotechnology, 1998

... Paper. A simple predictive model of layer inversion in binary solidliquid fluidized beds.Moh... more

A Dynamic Model of the Hydrodynamics of a Liquid Fluidized Bed

Industrial & Engineering Chemistry Research, 1994

The efficient design, operation, and scale up of novel fluidized bed bioreactors for direct coal ... more

Hydrodynamics of liquid fluidized beds including the distributor region

Chemical Engineering Science, 1992

An important application of liquid-solid fluidized beds has been developed recently in biotechnol... more An important application of liquid-solid fluidized beds has been developed recently in biotechnology, namely, immobilized biocatalyst bioresctors. For this application, experiments have been carried out to investigate the effect of distributor-induced flow nonuniformities on the hydrodynamics of liquid fluidized beds. The influence of important variables associated with the design of distributors has been studied including the effect of the density of the solid particles on the distributor region flow behavior. In the presence of the low-density particles (pa = 1.61 g/cm3). the influence of the distributor region was quite significant whereas, for high-density particles @, = 2.46 g/cm3), it was negligible. A new model has been proposed which accounts for the stirring effects of the high-velocity orifice jets in the distributor _ region.

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Generalized Richardson-Zaki Correlation for Liquid Fluidization of Binary Solids

Chemical Engineering & Technology, 1998

... Full Paper. Generalized Richardson-Zaki Correlation for Liquid Fluidization of Binary Solids.... more

Modeling of multi-solid liquid fluidized bed

Chemical Engineering & Technology, 1997

A dynamic model of the liquid fluidized bed containing two or more solid particle species of diff... more

Segregation velocity model for fluidized suspension of binary mixture of particles

Chemical Engineering and Processing: Process Intensification, 1998

A segregation velocity model is presented here to describe the segregation behaviour of the fluid... more

Synthesis, Characterisation and Biological Evaluation of Lanthanide(III) Complexes with 3-Acetylcoumarin-o-aminobenzoylhydrazone (ACAB)

CHEMICAL & PHARMACEUTICAL BULLETIN, 2005

ABSTRACT Lanthanide(III) complexes of the general formula [Ln(ACAB)(2)(NO(3))(2)(H(2)O)(2)].NO(3)... more ABSTRACT Lanthanide(III) complexes of the general formula [Ln(ACAB)(2)(NO(3))(2)(H(2)O)(2)].NO(3).H(2)O where Ln=La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III) and Y(III), ACAB=3-acetylcoumarin-o-aminobenzoylhydrazone have been isolated and characterised based on elemental analyses, molar conductance, IR, (1)H- and (13)C-NMR, UV, TG/DTA and EPR spectral studies. The ligand behaves in bidentate fashion coordinating through hydrazide &gt;C=O and nitrogen of &gt;C=N. A coordination number of ten is assigned to the complexes. Antibacterial and Antifungal studies indicate an enhancement of activity of the ligand on complexation.

Hydrodynamics of gas fluidized beds with mixture of group D and B particles

The Canadian Journal of Chemical Engineering, 2000

Page 1. Hydrodynamics of Gas Fluidized Beds with Mixture of Group D and B Particles Abdelhamid Aj... more

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