Methanol oxidation over Au/γ-Al2O3 catalysts

Methanol adsorption and reaction was investigated over Au/γ-Al2O3 catalysts. The catalysts were prepared by deposition precipitation (DP) and incipient wetness impregnation methods. The catalysts were used to catalyze the oxidation of methanol and characterised using X-ray diffraction (XRD), temperature programmed desorption(TPD), temperature programmed pulse flow reaction, scanning electron microscopy(SEM), X-ray photoemission spectroscopy (XPS) and Energy dispersive x-ray analysis (EDAX). The adsorption of methanol over γ-Al2O3 indicated a monolayer adsorption of methanol, forming methoxy group on the surface. The methoxy is relatively stable until 120oC, at which point dehydration to dimethyl ether occurs by bimolecular surface reaction. As the concentration of methoxy diminishes, so the mechanism reverts to a decomposition pathway, producing methane, CO and hydrogen (~340oC) in TPD. The gold supported on γ-Al2O3 play a role on the performance of the catalyst with respect to methanol oxidation. The oxidation reaction of Au/γ-Al2O3 catalysts prepared by deposition precipitation and incipient wetness impregnation both shows the reaction is complete oxidation to CO2 and H2O. However, it involved dehydration of methanol to dimethyl ether (DME) at about 150oC followed by decomposition of DME to CH4, CO, and H2. The main product from TPD is DME due to high surface coverage of methoxy species on the catalysts surface. The XPS, SEM, EDAX, indicated high dispersion of gold with complete methanol conversion attained at lower temperature compared to when γ-Al2O3 catalyst was used alone. Key Words: Au catalysis, methanol oxidation, methanol catalytic combustion, TPD, XPS, SEM, and EDA

Ethanol oxidation over Au/TiO2 catalysis

The adsorption and reaction of ethanol over Au/TiO2 catalysts was investigated using pulse flow reactor, DRIFTS, and TPD. The adsorption of ethanol over TiO2 (P25) indicated a full monolayer adsorption of ethanol, with much of it in a dissociative state, forming ethoxy group on the cationic sites and hydroxyl group at anions. The ethoxy is relatively stable until 300oC, at which point dehydration to ethene occurs by a bimolecular surface reaction. As the concentration of ethoxy on the surface disappears, so the mechanism reverts to a decomposition pathway, producing methane, CO and hydrogen (~320oC) in TPD. However, the presence of gold on the catalysts prepared by deposition precipitation method indicates that the reaction is complete oxidation to CO2 and water similar to Titania. The effect of the presence of low level of gold is marked with complete conversion of ethanol at low temperature (220oC) lower than Titania (240oC).Simultaneously, ethanol oxidation on Au/TiO2 catalyst was followed by dehydration to ethene at 300oC (characteristic of TiO2) and dehydrogenation to ethanal at high temperature. The pathway which gives ethene as seen on TiO2 remains, but a new feature of the reaction is the evolution of CO2 and H2 (a peak is seen in TPD above 350oC) and appears to be due to the production of formate species on the surface of the catalysts. This formate species is mainly involved in the complete oxidation reaction of ethanol on the catalysts. Keywords: Au catalysis, ethanol oxidation, ethanol catalytic combustion, TPD, DRIFT

Propan-1-ol Oxidation Reaction on Au/TiO2 Catalysts

Alcohols such as propanol and n- butanol have been oxidised to aldehydes by resin- supported gold in the liquid phase, and several other primary and secondary alcohols have been oxidised with very high selectivity in vapour phase over a 1wt% Au/SiO2 catalyst between 373- 573K. In this work, the adsorption of propan-1-ol was carried over 1%Au/TiO2 catalysts prepared by deposition precipitation method. This was further investigated using Pulse Flow reactor, TPFRP, TPD, and XRD,. The adsorption of propan-1-ol over TiO2 (P25) indicated a full monolayer with much of it in a dissociated state, forming propoxy group on the cationic site and hydroxyl group at anions. The propoxy is relatively stable until about 250oC, at which dehydration to propene occurs by bimolecular surface reaction. As the concentration of propoxy on the surface disappear, so mechanism reverts to a decomposition pathway, producing CO2 and H2O. However, the presence of gold on the catalyst is marked with complete conversion of propan-1-ol at low temperature (230oC) lower than Titania (300oC). Similarly, propan-1-ol oxidation on Au/TiO2 catalyst was followed by dehydration to propene at 300oC (Characteristic of TiO2) and dehydrogenation to propanal at high temperature. The evolution of CO2 and H2 appear to be due to the production of formate species on the surface of the catalyst. This formate species is mainly involved in the complete oxidation reaction of propan-1-ol on the catalysts.Keywords: Gold Catalysis, Propan-1-ol Oxidation, TPD, TPFRP, XR

IS TANZANIA’S LOGISTICS INFLUENCE CHINA'S FOREIGN DIRECT INVESTMENTS?: A QUANTITATIVE APPRAISAL

This study was conducted to evaluate the effect of the Tanzania Logistics on Chinese Foreign Direct Investment for the period 2007 to 2017 in Tanzania. The Simple Regression Model has been used to evaluate the Effects of Tanzania Logistics on Chinese Foreign Direct Investment over the period 2007 to 2017 in Tanzania. From world bank data and data published by author Han in 2019 the influence of Tanzania's logistics on Chinese foreign direct investment was analyzed in the 2007-2017 period in Tanzania. The findings of this study are quite interesting. Research findings reveal that there is a significant positive relationship between Tanzania Logistics and Chinese Foreign Direct Investment during the 2007 to 2017 period in Tanzania. The results showed that the Tanzania Logistics Affect the overall Chinese Foreign Direct Investment during the period 2007 to 2017 in Tanzania

Characterization of Foundry Sand Cores Bonded with Raw Nigerian Water Melon Seed Oil

Raw oil extracted from Nigerian variety of water melon seed was used as sole binder for foundry sand cores. Specimens were characterized for foundry properties that included baked tensile, green and baked compressive strengths; baked collapsibility, green permeability, bulk density and shatter index to determine the efficacy of the oil in the absence of additives for core application. Except the baked collapsibility test that was carried out at a temperature of 6000C, other specimens were oven baked at 2000C and oven cooled before the tests. Green permeability and compressive strength tests were carried out on freshly moulded specimens. Standard foundry laboratory/workshop equipment available at Nigerian Machine Tools Company Limited, Oshogbo was used to conduct tests under standard conditions. Results showed that cores with compositional mix of 1-3% water melon seed oil had adequate foundry characteristics for production of classes II-V iron and steel castings. Cores bonded with the oil were unsuitable for classes I and II iron/steel and non ferrous castings including copper, aluminium and magnesium alloy due to the poor baked tensile strength and collapsibility values. Results of green permeability, shatter index and compressive strength of tested cores were very sufficient for casting both ferrous and non-ferrous alloys. Keywords: Melon seed, oil, cores, baked, foundry, characteristics.

Day case haemorrhoidectomy in a developing country

No Abstract

Effects of Cassia occidentalis aqueous leaf extract on biochemical markers of tissue damage in rats

Purpose: Among the Hausas of Northern Nigeria, it is claimed by local (traditional) healers that the infusion of C. occidentalis leaves is used as a cure for hepatitis. This study was designed to evaluate the possible negative effects of the aqueous extract of this herb on serum total proteins, albumin, bilirubin, alanine amino transferase (ALT), aspartate amino transferase (AST) and alkaline phosphatase (ALP), as part of a larger study undertaken by these authors to ascertain the hepatoprotective potential of the plant extract. Methods: Fresh leaves of C. occidentalis were extracted with water and screened for phytochemical components. The extract was used for the treatment of 18 albino rats. Serum from these animals was used for the determination of the test parameters. Results: The extract showed hypoproteinaemic effect. ALT, AST and ALP levels were significantly elevated (P< 0.05). Conclusion: Hypoproteinaemic effects, and increase in ALT, AST and ALP are indications that the crude extract of C. occidentalis leaves may be slightly toxic as a concoction for liver ailments. Keywords: C. occidentalis, Liver, Serum proteins, Transaminases, Hypoproteinaemic effectsTropical Journal of Pharmaceutical Research Vol. 7(4) 2008: pp. 1137-114

Development of Manually Operated Orange Peeling Device for Domestic Use

Orange a very rich source of vitamin C is a perishable fruit that can only be stored unpreserved for few days before its biological degeneration. When processed to juice, the chemical preservatives that are usually added coupled with the contaminations by its back skin fluid instantly change its natural flavor. This has made many consumers to still prefer freshly peeled fruit to its processed juice. As a solution to laborious hand peeling process that is highly prone to injury due to the sharp tools used several devices have been developed for its peeling. Each of these has its own technical, economic and other shortcomings. This work designed and fabricated a manual orange peeling device with a capability of processing oranges for a domestic family household. The device incorporated a rotary handle through which power was introduced into the system, power screw, spur gear train mounted on a base and cutting blade that performed the peeling function. The fabricated device was operated and assessed to have a peeling efficiency of 97%, generated 2.6% over peeled and damaged oranges and a capacity to peel about 140 oranges per hour as compared to hand peeling that can produce 32 peeled oranges per hour. It is robust, simple to operate and maintain, had good aesthetics and light weight of 619g due to transparent light but strong plastics used to construct the frame and base. Keywords: Orange, peeling, device, household, juice

Hybridizing Effect of Palm Frond Fibre on Helmet Shell Cast from Elaeis Guineensis Male Flower Bunch Fibre Reinforced Biocomposite

Biomass fibres obtained from agricultural wastes have found application in the production of structural reinforcement for bio-composites used for manufacturing of engineering components because of their low cost, biodegradable and eco-friendly advantages. Ademoh and Olanipekun (2014) had produced motorcycle safety helmet using a bio-composite reinforced with 20% male flower bunch stalk fibre. In this research, 20% weight of treated hybrid composite from treated oil palm male flower bunch stalk fibre and oil palm frond fibre in the ratio of 3 to 1 respectively were used in reinforcing unsaturated polyester resin to fabricate anti-crash helmet shell using hand lay-up method. The mechanical performance of the helmet shell was determined and the results obtained were compared with past literatures. From the result, hybrid composite of oil palm male flower bunch stalk fibre hybrid and oil palm frond fibre with unsaturated polyester has good mechanical attributes and can replace ABS plastic commonly used in conventional helmet productions. On comparison with immediate preceding work of Ademoh and Olanipekun (2014) the 15% male flower bunch/5% palm frond reinforced bio-composite of this study showed improvement 77.06% on modulus; 68.20% on impact strength and 13.61% on harness and reduction of 21.04% on toughness. Keywords:  palm frond fibre, male flower bunch stalk,  fibre, polyester, helmet shell

Indications and outcome of pediatric tracheostomy: results from a Nigerian tertiary hospital

<p>Abstract</p> <p>Background</p> <p>There is a change in the concept of pediatric tracheostomy. This study investigates the indications and outcomes of pediatric tracheostomy in a Nigerian teaching hospital finding out whether there is also a change in the trend in our environment as compared to other centers.</p> <p>Methods</p> <p>A retrospective chart review of 46 patients aged between 2 months and 15 years who presented to our Otorhinolaryngological facility and had tracheostomy between January 2000 and December 2008.</p> <p>Results</p> <p>The age range was 2 months to 15 years. There were 29 males and 17 females. Thirty two (69.6%) patients were in the age range 6-10 years. Forty tracheostomies (87%) were performed as emergency while 6 (13%) as elective procedures. The commonest indication for tracheostomy was upper airway obstruction (n = 29, 63%). Transverse skin incision was employed in all the cases. No intra-operative complication was recorded. The post-operative complication rate was 15.2%. The duration of tracheostomy ranged from 5 days to 3 months. All the patients were successfully decannulated. The overall mortality was 8 (17.4%). There was no tracheostomy related mortality.</p> <p>Conclusions</p> <p>There is no increase in the incidence of tracheostomy in patients under 1 year of age and the commonest indication for the procedure in Nigeria has remained relief of upper airway obstruction. Pediatric tracheostomy is safe when performed in the tertiary hospital setting.</p