Glassy Aging with Modified Kohlrausch-Williams-Watts Form

In this report we address the question whether aging in the non equilibrium glassy state is controlled by the equilibrium alpha-relaxation process which occur at temperatures above Tg. Recently Lunkenheimer et. al. [Phys. Rev. Lett. 95, 055702 (2005)] proposed a model for the glassy aging data of dielectric relaxation using a modified Kohlrausch-Williams-Watts (KWW) form. The aging time dependence of the relaxation time is defined by these authors through a functional relation involving the corresponding frequency but the stretching exponent is same as the alpha-relaxation stretching exponent. We present here an alternative functional form directly involving the relaxation time itself. The proposed model fits the data of Lunkenheimer et. al. perfectly with a stretching exponent different from the alpha-relaxation stretching exponent.Comment: 1 TeX file, 10 eps figure

Child labor and household wealth: Theory and empirical evidence of an inverted-U

Some studies on child labor have shown that greater land wealth leads to higher child labor, thereby casting doubt on the hypothesis that child labor is caused by poverty. This paper argues that the missing ingredient is an explicit modeling of the labor market. We develop a simple model which suggests an inverted-U relationship between land holdings and child labor. A unique data set from India that has child labor hours information confirms this hypothesis. It is shown that the turning point beyond which more land leads to a decline in child labor occurs at 3.6 acres of land per household, which is well below the observed maximum value of and-holding.child labor, land-holding, education, labor markets

Child Labor and Household Wealth : Theory and Empirical Evidence of an Inverted-U

Some studies on child labor have shown that, at the level of the household, greater land wealth leads to higher child labor, thereby casting doubt on the hypothesis that child labor is caused by poverty. This paper argues that the missing ingredient may be an explicit modeling of the labor market. We develop a simple model which suggests the possibility of an inverted-U relationship between land holdings and child labor. Using a unique data set that has child labor hours it is found that, controlling for child, household and village characteristics, the turning point beyond which more land leads to a decline in child labor occurs around 4 acres of land per household.child labor ; land-holding ; labor markets

Hemoglobin E genotypes and fertility: a study among the Ahom of Upper Assam, India

Background: Differential fertility is reported in areas where prevalence of hemoglobin E (Hb E) is high. At this backdrop a representative Ahom sample from Upper Assam is studied to examine if differential fertility exist between Hb E and normal Hb A mothers and whether there is significant difference between them with regard to the hemoglobin (Hb) concentration.Methods: Detailed reproductive histories are collected from 119 Ahom couples followed by Hb typing by ‘Cellulose Acetate Gel’ electrophoresis (pH 8.9) and fetal hemoglobin (Hb F) determined by Acid Elution technique. Hb concentration (in g/dl) is measured by Sahley’s method. Results: The calculated Hb E allele frequencies for the Ahom male and the female subjects are 0.424 and 0.403 respectively. β-carrier frequency in the total sample is found to be 0.42%. There is no differential fertility observed between Hb A/Hb A (AA), Hb A/Hb E (AE) and Hb E/Hb E (EE) mothers. Reproductive performance of the couples revealed that the mothers with an Hb E complement either heterozygous or homozygous are more likely to have a spontaneous abortion or an infant mortality. Conclusions: It may be concluded that Hb E induced anemia may increase spontaneous abortion and infant mortality in AE and EE mothers

Manufacture of urea

Urea is in many ways the most convenient form for fixed nitrogen. It has the highest nitrogen content available in a solid fertilizer (46 %). It is easy to produce as prills or granules and easily transported in bulk or bags with no explosive hazard. It leaves no salt residue after use on crops. Its specific gravity is 1.335, decomposes on boiling and is fairly soluble in water. The principal raw materials required for this purpose are NH3 & CO2.Two reactions are involved in the manufacture of urea. First, ammonium carbamate is formed under pressure by reaction between CO2 & NH3. CO2 + 2NH3 NH2COONH4 H= -37.4 Kcal This highly exothermic reaction is followed by an endothermic decomposition of the ammonium carbamate. NH2COONH4 NH2CONH2 + H2O H= + 6.3 Kcal Various processes for the manufacture of urea are: 1) Snamprogetti ammonia stripping process 2) Stamicarbon CO2 stripping process 3) Once through urea process 4) Mitsui Toatsu total recycle urea process We selected the Snamprogetti ammonia stripping process for the manufacture of urea. In this process ammonia & CO2 are compressed & fed to the reactor. The unconverted carbamate is stripped and recovered from the urea synthesis reactor effluent solution at reactor pressure, condensed to an aqueous solution in a steam producing high pressure condenser & recycled back to the reactor by gravity. Part of the liquid NH3 reactor feed, vapourized in a steam heated exchanger, is used as inert gas to decompose & strip ammonium carbamate in the steam heated high pressure stripper. Energy balance & material balance of the plant is done. The selected capacity of the plant is 4,50,000 tons/year of urea producing 62,500 kg/hr of urea with 98 % purity. Urea reactor & vacuum evaporator are designed. The volume of reactor is calculated & found to be 195 m3. The length & diameter of the reactor are 40 m & 2.5 m respectively. The evaporator used is of climbing-film long- tube type. Snamprogetti ammonia-stripping urea process is selected because it involves a high NH3 to CO2 ratio in the reactor, ensuring the high conversion of carbamate to urea. The highly efficient ammonia stripping operation drastically reduces the recycling of carbamate and the size of equipment in the carbamate decomposition . Snamprogetti technology differs from competitors in being based on the use of excess ammonia to avoid corrosion as well as promote the decomposition of unconverted carbamate into urea. Uses of Urea: • About 56 % of Urea manufactured is used in solid fertilizer. • About 31 % of Urea manufactured is used in liquid fertilizer. • Urea-formaldehyde resins have large use as a plywood adhesive. • Melamine-formaldehyde resins are used as dinnerware & for making extra hard surfaces

A REVIEW ON BIOLOGICAL ACTIVITIES AND MEDICINAL PROPERTIES OF CLERODENDRUM INFORTUNATUM LINN

India has a great wealth of various naturally occurring herbal drugs which have great potential pharmacological and physiological activities. Since ancient times, several diseases have been treated by the administration of plant parts based on traditional and folk uses. Clerodendrum infortunatum Linn is one of them. Considerable utilisation and progress have been achieved regarding its biological activities. The whole parts of the plant contain different medicinally active substances which were variously used in Ayurveda, Unani and Homeopathy system of medicines. Its root, leaf and stem extract are used in microbial infection. Leaf extract is used as anthelmintic, analgesic, anticonvulsant, antidiabetic agent and also to increase haemoglobin level in the blood. Clerodolone, clerodone, clerodol are different isolated compounds obtained from this plant. A sterol, now designated as clerosterol obtained from the leaves and roots of C. infortunatum is used as an antitumor agent. This communication explains the evidence-based information regarding the different pharmacological activities with a correlation of chemical constituents available with this plant so that it may serve as a reference for further studies

ANTIMICROBIAL INVESTIGATION AND BINDING MODE ANALYSIS OF SOME NEWLY SYNTHESIZED 4-AMINO-5-((ARYL SUBSTITUTED)-4H-1, 2, 4-TRIAZOLE-3-YL)-THIO LINKED HYDROXAMIC ACID DERIVATIVES

Objective: A series of 5-substituted-4-amino-1, 2, 4-triazole-linked hydroxamic acid derivatives have been synthesized and explored in vitro to evaluate antibacterial and antifungal activities. Methods: Different 5-phenyl group substituted-4-amino-1,2,4-triazole-3-thiol reacted with chlorine substituted hydroxamic acid to produce the desired compounds and characterized spectroscopically. Minimum inhibitory concentration (MIC), zone of inhibition (ZOI), growth kinetic studies, and scanning electron microscopy (SEM) were employed to elicit the antimicrobial efficacy of synthesized compounds against a wide range of bacterial and fungal strains. Results: Compounds 6a, 6b, 6d, and 6k (MIC of 25 μg/ml) have been found to be more potent against Klebsiella pneumoniae, Bacillus cereus, Bacillus pumilus, Micrococcus luteus, and Pseudomonas aeruginosa, compounds 6a-6d, 6k, and 6l (MIC of 25–50 μg/ml) have shown potent antibacterial efficacy against Klebsiella pneumonia, P. aeruginosa, and Vibrio cholera compare to the standard drug amoxicillin (MIC of 60 μg/ml, 65 μg/ml, and 25 μg/ml, respectively). Screening for the antifungal activity revealed that the compounds were found to be most active against Candida albicans (6a, 6b, and 6l), Candida tropicalis (6b and 6d), and Aspergillus niger (6a, 6b, 6d, and 6j) with MIC of 15–25 μg/ml. Bacteriostatic and fungistatic effect of titled compounds was revealed from growth kinetics study. Conclusion: Electron donating group at the 5-position of the 5-substituted-1,2,4-triazole-linked hydroxamic acid derivatives conferred the biological effectiveness of the synthesized compounds and also offer a therapeutically effective prototypical structure for further development of new chemical entities with superior antimicrobial activity