ABSTRACT The current commercial production of biodiesel is via transesterification reaction, catalysed by homogeneous or heterogeneous catalysts. The most commonly used catalyst in biodiesel production is the homogeneous alkaline catalysts such as NaOH, KOH, CH3ONa and CH3OK. The choice of these catalysts is based on their higher kinetic reaction rates. However because of high cost of refined feedstocks and difficulties associated with the use of homogeneous alkaline catalysts to transesterif...
Abstract This work has investigated the corrosion behavior of low carbon steel subjected to four different modes of iso-thermal heat treatment and then immersed in a neutral buffer corrosive medium containing carbonate and chloride ions.The low carbon steel material was cut into twenty small pieces of length 18±2mm, put in groups of five and subjected to: Annealing, Hardening, Normalizing and tempering, each corresponding to an iso-thermal mode of treatment. The samples were ground and poli...
Abstract This study investigated the effect of magnesium and calcium as spheroidizers on the graphite microstructure in cast iron. The cast iron samples were melted in an induction furnace with charge of known composition and, magnesium and calcium of known percentages were added as spheriodizers to the molten metal in the mould during the casting process. From the microstructure of the as- cast specimens it was observed that the use of 100% Mg and a combined addition of 60% and 40%Ca as sph...
ABSTRACT The properties of cast iron grade GL 250 are dependent on the microstructures developed during casting. These microstructures are in turn dependent on the composition of the alloy, type of mould and other numerous casting practice variables such as shake-out time, pouring temperature, mould ambient conditions and inoculating technique. In this work, the effect of silicon content and shake-out time on the grain size (GS) and hardness properties of GL 250 cast iron was studied using a...
ABSTRACT Incinerator ash was investigated for its potential use as a replacement for sand and cement in concrete interlocking bricks. The physical characteristics of the raw materials were examined. Two sets of mixes were prepared. For the first set, sand and water quantities were fixed while incinerator ash was used at 0% to 100% replacement by weight for cement in steps of 10%. In the second set, incinerator ash was used at 0% to 100% replacement by weight for sand while cement and water q...
ABSTRACT This term paper contributions nanotechnology and dives into the world of nanotechnology and its and possibilities it can offer to the society The and nanomaterials immense impact of extends from its medical, ethical, mental, legal environmental applications, to fields such as engineering, biology, chemistry, computing, materials science, and communications. Alas, nothing is ever as it seems and perf...
Investigation of the low carbon steel bends into different angles with dimension 50 mm X 20 mm and then plated in Nickel bath at 3V for 25 minutes subjected to NaCl and H2SO4 corrosive environment. This research investigated the corrosion resistance of nickel- plated and un-plated low carbon steel and in a corrosive environment of H2SO4 and NaCl solutions. Weight loss method was used for estimation the corrosion rate in the current study. Low carbon steel sample was nickel electroplated at�...
The quality of castings in a green sand mould is influenced significantly by its properties, such as green compression strength, permeability, mould hardness, and others, which depend on input parameters. The relationships of these properties with the input parameters, like sand grain size and shape, binder, water, clay, etc. are complex in nature. The goal of this paper is to determine the green sand mould compressive strength in case of input parameters. A good moulding sand however, must p...
Abstract This research technically aims at utilizing stone dust as reinforcement to check the mechanical properties of Al(6063) with different weight ratio of the reinforcement. The alloy consisting of 0, 2, 6 and 10 wt% of the reinforcements were produced using double stir casting method. Evaluation of the microstructure, percentage porosity check, measurement of density and mechanical properties of the composites produced were used to check the performance levels of the composite produced. ...
Room temperature tribocorrosion behaviour of Al-4.5%Cu/SiC particulate composite was evaluated against stainless steel ball in natural sea water. Ab-initio, the Al-4.5%Cu was reinforced with 5,10,15 and 20 % SiC reinforcements to produce the Al-4.5%Cu/SiC particulate composite by stir casting method. The tribocorrosion test was carried out with an Anton Paar Tribometer at applied loads of...
Contribution of carrier recombination from the p/i interface regions and the bulk to the dark current–voltage (JD–V) and short-circuit current–open-circuit voltage (Jsc–Voc) characteristics of hydrogenated amorphous-silicon (a-Si:H) p–i–n and n–i–p solar cells have been separated, identified, and quantified. Results are presented and discussed here which show that a maximum 1 sun Voc for a given bulk material can be validly extrapolated from bulk dominated Jsc–Voc characteri...
Studies have been carried out on high quality hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells with protocrystalline i-layers to establish the nature of p/i interfaces and to quantify their contributions to various solar cell characteristics. The p-a-SiC:H,B/i-a-Si:H/n-μcSi:H,P cell structures used had the a-Si:H i-layers deposited from hydrogen diluted silane with R≡[H2 ]/[SiH4]=10. The high quality p/i interface regions obtained with R=10, indicated by the high and stable open c...
A systematic study has been carried out to quantify the effect of microcrystallite nucleation in the intrinsic layer of protocrystalline Si:H p-i-n solar cells prepared by rf plasma enhanced chemical vapor deposition (PECVD). Real-time spectroscopic ellipsometry (RTSE) results that have previously identified the transitions from amorphous to microcrystalline phase were confirmed with atomic force microscopy (AFM) images. The effects of the phase transitions in the bulk intrinsic layer, as wel...
Insights into the growth processes and evolution of microstructure in intrinsic hydrogenated silicon (Si:H) films obtained from real-time spectroscopic ellipsometry (RTSE) are extended to the characterization of the optoelectronic properties of the corresponding solar cells. To assess the effects of transition regions from the amorphous to mixed microcrystalline phases, cell structures with and without such regions at different depths in the i-layer from the p-contact have been investigated. ...
As the negative environmental effects of the current use of non-renewable energy sources have become apparent, hydrogenated amorphous silicon (a-Si:H) solar cell technology has advanced to provide a means of powering a future sustainable society. Over the last 25 years, a-Si:H solar cell technology has matured to a stage where there is currently a production of 30 MWpeak/year; and this production capacity continues to increase. The progress is due to the continuous advances made in new materi...