Influence of Thermal Treatment on Kankara Kaolinite

In this work, the influence of thermal treatment on the structure of Kankara kaolinite was studied for the first time, using X-ray diffractogram (XRD), EDX, NanoSEM, FTIR-Attenuated Total Reflectance, DTA/TGA and BET surface area measurements. The treatment temperatures applied represents the peak of the transformation stages. The results show that surface area decreases with increase in temperature of treatment, while its crystal structure was transformed from the native kaolinite structure via the amorphous metakaolin to the typical mullite/crystobalite structure though with some unidentifiable peaks. The morphological studies showed that Kankara kaolinite is composed of nano-platelets of about 30nm thickness and in bundles of between 1 – 3 µm thicknesses with some marked variations/reductions as the treatment temperatures increases. The DTA/TGA result shows that the kaolinite undergoes dehydroxylation at 528.560C while been converted to metakaolin with a weight loss of about 14.4%. The presence of the characteristic OH, Al-OH, Si-OH and Si-O-Al bands were confirmed with the ATR studies which also showed the disappearance and subsequent appearance of new bands as the treatment temperature increased, this also affected the surface area and pore sizes of the transformation products

Optimization of Steam Distillation of Essential Oil of Eucalyptus tereticornis by Response Surface Methodology

This paper deals with optimization of yield of Eucalyptus tereticornis oil in steam distillation using response surface methodology (RSM). The factors considered were mass of solute/solvent ratio (A), extraction time (B) and steam rate (C). These parameters were varied at two levels. Conditions of optimum oil yield predicted were 105 min of extraction time and 0.032 kg/h steam rate. These factors gave an optimum oil yield of 2.05 %. Significant model terms were time, steam rate, and the interactions between them. Analysis of variance (ANOVA) indicates that the model was significant as evidenced from R2 of 0.9844 and the model F-value of 49.13. The oil yield predicted by the model was closed to the experimentally determined values (1.85 % and 1.87 % respectively); hence the model can be used for prediction of oil yield in essential oil extraction from E. tereticornis leaf via steam distillation method.Keywords: RSM, Eucalyptus tereticornis, steam distillation, Box-Bohnke

Risk factors for peritoneal dialysis catheter failure in children

Background Peritoneal dialysis catheter (PDC) failure still remains a common clinical problem in pediatric patients despite advancements in catheter placement and dialysis techniques. Our aim was to determine the risk factors that may lead to PDC failure, especially those factors that could be potentially modified to minimize PDC failures.Patients and methods This study was designed as a retrospective chart review of 31 patients less than 12 years of age who had end-stage renal disease (ESRD) on whom a total of 54 operative PDC placements were carried out at the tertiary Children’s Hospital, King Fahad Medical City, Riyadh, Saudi Arabia, from January 2007 to December 2010. The data included patient demographics and perioperative and operative variables.Results Fifty-four PDCs were inserted in 31 pediatric patients with ESRD, of whom 17 (55%) were boys and 14 (45%) were girls. Young age showed a statistically significant effect on PDC failure [1.8 (± 5) vs. 5 (± 7.8), P = 0.007], whereas weight did not (P = 0.085). Five types of PDCs were used, which showed significant association with PDC failure (P =0.009). Supraumbilical paramedian abdominal entry incisions were used in 49 (90.7%) patients without peritoneal leakage in any case. Nonsimultaneous omentectomy and upward PDC exit site orientation showed significant association with PDC failure (Pr0.001). The causes of PDC failure included idiopathic peritonitis in 13 (56.5%), PDC occlusion by omentum in five (21.7%), PDC malposition in four (17.4%) patients, and PDC leakage in one (4.4%) patient. Peritonitis showed a high statistical significance in PDC failure with P value of less than 0.001. The serum albumin level at the time of PDC insertion was not statistically significant in terms of PDC failure (P = 0.40) but had a high association with idiopathic peritonitis.Conclusion Our study provides some recommendations to minimize PDC failures that include improvement of patients’ nutritional status, use of a swan-neck double-cuffed catheter, paramedian abdominal entry incision, simultaneous omentectomy, downward orientation of exit site, and use of an up-to-date technique by a dedicated team for proper use of PDC. However, prospective studies possibly on a multicentric basis are necessary to standardize the best PDC insertion and maintenance techniques to minimize PDC failures and improve the quality of life for children with ESRD. Keywords: end-stage renal disease, pediatric patients, peritoneal dialysis, tenckhoff cathete

On managing complex adaptive systems motivated by biosystems application to infections

Many attempts to control Complex adaptive systems (CAS) have failed. Here we try to learn from biosystems to derive some principles for CAS management. An application to managing infections is given

Effect of Sources of Organic Manure on Growth and Yields of Okra (Abelmoschus esculentus L.) in Sokoto, Nigeria

Field experiments to investigate the effect of different sources of organic manure (Cow, Sheep and Poultry Manure) on growth and yield of okra was carried out at the Teaching and Research Fadama Farm of Usmanu Danfodiyo University Sokoto, Nigeria during 2007/2008 and 2008/2009 dry seasons. Treatments were laid out in a randomized complete block design (RCBD) with three replications. Data were collected on growth and yield parameters (Plant height, number of leaves per plant, pod length and fresh pod weight). Results obtained indicated that growth and yield of okra was lowest in control treatments which showed that the organic manures used in the study especially poultry manure positively influenced the performance and yield of okra. Poultry manure positively increased okra plant height by 39.4% and number of leaves by 37.8% compared to control treatments. There was no significant effect with respect to number of leaves in 2007/2008. Fresh pod weight was significantly increased by 34.6% with poultry manure compared to control treatments. However, pod length was not significantly affected by the treatments. Based on the findings of the experiments it could be deduced that poultry manure seems to promote higher growth and yield of okra. Thus, it should berecommended for farmers growing okra in this zone.Keywords: Okra, Growth, Yield, Source, Organic Manur

Impact of Heat and Mass Transfer on MHD Oscillatory Flow of Jeffery Fluid in a Porous Channel with Thermal Conductivity, Dufour and Soret

The objective of this paper is to study Dufour, Soret and thermal conductivity on unsteady heat and mass transfer of magneto hydrodynamic (MHD) oscillatory flow of Jeffery fluid through a porous medium in a channel. The partial differential equations governing the flow have been solved numerically using semi-implicit finite-difference scheme with the aid of MATLAB software. The results obtained are displayed graphically and in tabular form to illustrate the effect of various parameters on the dimensionless velocity, temperature and concentration profiles, to show the effects of different parameters entering in the problem. Results from these study shows that velocity and temperature increases with the increase of Soret and Dufour why the thermal conductivity increases as temperature profile increasing. Also, it is observed that soret number increases as concentration profile decreases.Keywords: Heat and Mass Transfer, Dufour, Soret, Jeffery Fluid and Thermal Conductivit

THE STUDY OF THERMAL EFFECT ON THE SURFACE PROPERTIES OF GAMMA-ALUMINA SYNTHESIED FROM KANKARA KAOLIN.

Gamma alumina is a good material for catalyst support and its surface properties is of great importance. In this study the gamma-alumina (γ-Al2O3) synthesized to be used as catalyst support for zeolite catalyst was obtained by calcination of ammonium alum an intermediate product prepared from kaolin which was sourced from Kankara, Katsina, Nigeria. The surface properties were determined using BET technique. BET specific surface area of gamma alumina produced at 825°C for soaking time of 3h was 120m2/g while at 850°C for soaking time of 4h the surface area was 140m2/g. The pore size and pore volume range from 15nm to 25nm and 0.5cm3/g to 0.8cm3/g respectively. The XRD pattern obtained at 825°C and 875°C calcination temperatures conformed to the standard pattern of gamma-alumina, having the strong peaks at Bragg angles of 67, 46, 39 and 38°. The SEM image showed clearly the plate-like structure of gamma alumina. Thus kankara kaolin is a promising material for the production of gamma alumina. http://dx.doi.org/10.4314/njt.v35i1.1

ALUMINA PHASE TRANSFORMATION FROM THERMAL DECOMPOSITION OF AMMONIUM ALUM SYNTHESIZED FROM KANKARA KAOLIN

Thermal stability of transitional alumina phases produced from ammonium alum using Kankara kaolin as starting material was studied. Wet beneficiation method was employed to purify the starting material, after which it was calcined and dealuminated with sulphuric acid. The elemental composition, mineralogical, and physiological analyses were carried out using X-ray fluorescence (XRF), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) techniques respectively. The ammonium alum was thermally treated by varying the calcination temperature from 700 to 1200°C and varying the time of calcination from 1 to 4 h. The formation of gamma alumina began at calcination temperature of 825°C for calcination time of 3 h, which was found to be lower than reported works of 900°C. It was found to be stable at higher temperature of 1125°C, above which phase transformation to alpha alumina was observed. The observed wide range of thermal stability of the gamma alumina phase gives it good advantage to be used for high temperature applications, such as support for catalyst promoters. Alpha alumina phase formation began at 1150°C and was fully formed at 1200°C. BET specific surface area of 166 m2/g was obtained for the gamma alumina phase which was high enough for it application as support for catalyst, catalyst and adsorbent. http://dx.doi.org/10.4314/njt.v36i3.2

Evaluation of Hepatotoxic effects of Leaves Extract of Cassia italica (Mill.) Lam. ex F.W. Ander (Leguminosae) in Albino Rats

The hepatotoxic effect of aqueous leaves extract of Cassia italica on some liver function parameters was investigated in albino rats. Five groups of the rats were administered the following graded doses of the extract orally: 0, 300, 600, 1500 and 3000 mg/kg bw, for groups 1, 2, 3, 4 and 5 respectively, once daily for 28 days. The serum ALAT, ASAT and ALP levels were found to increase significantly (p<0.05) in all the groups when compared to the control; whereas the serum Albumin levels decreased significantly (p<0.05) in all the groups when compared with the control. There was also a significant increase in Total Bilirubin level (p<0.05) in the groups administered with 3000 and 1500 mg/kg bw, but the reverse was the case in the groups administered with 600 and 300 mg/kg bw of the extract, which showed significant decrease (p<0.05) when compared with the control. These results suggest that, the aqueous leaves extract of Cassia italica has adverse effects on the functional capacities of rat liver.Keywords: Hepatotoxicity, extract, Cassia italic, rat

DEVELOPMEMT OF PILOT SCALE DEALUMINATION UNIT OF 2.5 kg METAKAOLIN PER BATCH CAPACITY

A pilot-size dealumination unit to handle 2.5kg of metakaolin per batch was designed and fabricated and test run. The metakaolin was prepared from Kankara kaolin. The metakaolin was completely split into silica and alumina. The silica component which was inert to the sulphuric acid used during the reaction and was obtained as a solid product. While the alumina which reacted with the sulphuric acid was obtained in liquid form as aluminum sulphate, known as alum. The dealumination unit comprises of the dealumination reactor, known as dealuminator, acid holding tank and metakaolin slurry mixing tank. The material of construction selected for the dealumination reactor was stainless steel type 304 lined internally with glass to withstand the corrosive environment of the concentrated sulphuric acid at the reaction temperature > 140°C. The capacity of the componentsare; acid holding tank 5 liters;metakaolin slurry mixing tank 20 liters, with 70 W capacity motor and the dealuminator 50 liters, which had pressure relief valve, pressure gauge (0-10 bars) and temperature gauge (0 - 300°C) on the cover. Woven glass fiber cloth was used as lagging material to minimize heat lossto the surrounding. The purity level of the silica obtained from the reaction was above 95%.The endothermic nature of the dealumination process was void of external heating. http://dx.doi.org/10.4314/njt.v36i3.2