Analysis of temperature variations in fixed-bed columns using non-isothermal and non-equilibrium transport model

A non-isothermal and non-equilibrium two-component lumped kinetic model of fixed-bed column liquid chromatography is formulated with the linearized isotherm and solved analytically to study the influence of temperature variations on the process. The model equations constitute a system of convection-diffusion PDE for mass and energy balances in the bulk phase coupled with differential equations for mass and energy balances in the stationary phase. The analytical solutions are derived for Dirichlet boundary conditions by implementing the Laplace transformation, Tschirnhaus-Vieta approach, the linear decomposition technique and an elementary solution technique of ODE. An efficient and accurate numerical Laplace inversion technique is applied to bring back the solution in the actual time domain. In order to validate the derived analytical solutions for concentration and temperature fronts, the high resolution upwind finite volume scheme is applied to approximate the model equations numerically. Various case studies are carried out assuming realistic model parameters. The results obtained will be beneficial for interpreting mass and energy profiles in non-equilibrium and non-isothermal liquid chromatographic columns and provide deeper insight into the sensitivity of the separation process without performing costly and time-consuming laboratory experiments

Smoking among males in a low socioeconomic area of Karachi

Approximately half of the families in Pakistan reported having at least one smoker in 1992. Smokers were less educated, poorer and more likely to come from a rural background than non-smokers. The proportion of family earnings in poor families with marginal incomes, may be substantial. We conducted this survey to determine the prevalence of cigarette smoking in males over 15 years of age in Azam Basti, an urban squatter settlement of Karachi where 31% of the children less than 5 years old were malnourished. A pretested, structured questionnaire was administered to males aged fifteen years and above, from randomly selected homes in Azam Basti. In our sample of 102 persons the respondents were 38 years old on average, and earned about Rs. 4,500 (US $130) per month. Persons with 10 or more years of education were thrice as likely to have never smoked as compared to those with less than ten years of schooling, (OR = 3.6, 95$140) (OR = 2.4, 95% confidence interval 0.8, 7.3). Smoking is common in urban squatter settlements in Pakistan. Parental smoking and its relationship with malnutrition in children under five is not well documented or publicized, even though there is evidence that it has a contribution. We propose that primary health care programs consider smoking prevention and cessation as community based interventions

Synthesis, spectral characterization and antioxidant activity of a supramolecular copper (II) complex obtained from pyridine-2, 6- dicarboxylic acid and 3,5-diamino - 1, 2, 4-triazole.

A supramolecular copper (II) compound, (HdatrzH)[Cu (Hdipic) (dipic)].3H2O (1) (Hdatrz = 3,5-diamino-1,2,4- triazole, dipic = pyridine- 2,6-dicarboxylic acid) was synthesized and characterized by elemental analysis, Fourier transformed infrared spectroscopy (FT-IR), UV-Visible spectroscopy, mass spectrometry, proton nuclear magnetic resonance (1H-NMR), thermal analysis, and magnetic susceptibility measurement. The room temperature magnetic susceptibility measurement showed a magnetic moment of 1.67 BM for compound 1, deviating slightly from the spin-only magnetic moment value for Cu (II) ion. Thermogravimetric analysis revealed three decomposition stages for compound 1. The compound showed no activity against all the tested microorganisms. Interestingly, compound 1 exhibited a significant radical scavenging activity (RSA)

Sterol composition of marine algae from Karachi coast of Arabian Sea

During the course of chemical investigation of marine algae collected from Karachi coast of Arabian Sea, five sterols named as sarangosterol(1), 23-methyl cholesta-5, 25-dien-3ß-ol(2) from Endarachne binghamiae (brown alga), sargasterol(3) from Dictyota indica (brown alga), cholesterol(4) from Laurencia obtusa (red alga) and clerosterol(5) from Codium iyengarii (green alga) have been isolated. Their structures were elucidated with the help of spectroscopic means

Screening of systemic fungicides and biochemicals against seed borne mycoflora associated with Momordica charantia

Study of seed borne fungi associated with bitter gourd seeds were conducted under in vitro condition in Department of Plant Pathology, Bahauddin Zakariya University, Multan, Pakistan. Two hundred (200) seed samples of Momordica charantia (bitter gourd) were collected from southern regions of Punjab province (Multan, Khanewal and Bahawalpur). Six fungal species were isolated out of which Aspergillus flavus showed highest percentage that is, 27.3% followed by Rhizopus stolonifer 17.98%, Alternaria alternata 13.34%, Aspergillus niger 5.23%, Myrothecium roridum 7.37% and Fusarium solani 6.69%. More number of fungi was observed by using blotter paper technique when compared with agar plate method. Of the three systemic fungicides used include ridomil gold MZ, bavistin, and score; and two low cost chemicals such as salicylic acid and boric acid. Ridomil gold MZ gave good results at all concentrations (20, 30 and 40 mg/10 ml) against all the isolated fungi compared with other fungicides. Salicyclic acid gave the best results against isolated fungi compared to boric acid.Key words: Myrothecium roridum, bitter gourd, salicyclic acid, southern Punjab, bavistin, Pakistan