3,521 research outputs found

    Optimization of Levulinic acid production from groundnut shell using Taguchi orthogonal array design

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    The exploitation of lignocellulosic biomass is receiving an increasing attention due to its renewability, abundance and low price value, and can be converted into various valuable platform compounds such as furfural, lactic acid, formic acid and levulinic acid. Among these products, levulinic acid (LA) is the main compound of biomass hydrolysis, which has been classified by the United States Department of Energy as one of the top-12 promising building blocks. This work reported the transformation of groundnut shell into LA. The production of LA was carried out in a 50 cm3 Teflon lined stainless steel reactor. The LA produced was extracted from the aqueous mixture using ethyl acetate, about 1g of sodium sulphate anhydrous were added to remove the water in the organic layer after the aqueous layer was drained and then heated at a temperature of about 78 oC for the solvent to evaporate and LA was the residue. The production process was optimized using a Taguchi orthogonal array design, with optimum yield of 74.54 % at reaction conditions of temperature (180 °C), time (3.5 h), and acid concentration (0.3 M). The FT-IR spectrum of the produced LA showed absorption at about 1705.13 cm-1 and 3039.91 cm-1 indicating the conjugated carbonyl and the hydroxyl of carboxylic acid functional group. It was recommended that high yields of LA can be achieved across a range of optimization variables as long as two out of the three conditions are met: high acid catalyst concentration, long reaction time or high temperature within the range tested, as LA is relatively stable once formed. Moreover, the results obtained revealed that groundnut shell could be a potential substrate for levulinic acid production. Keywords: Groundnut shell, Levulinic acid, Optimization, Hydrolysis, Taguchi design

    Forecasting wind speed data by using a combination of ARIMA model with single exponential smoothing

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    Wind serves as natural resources as the solution to minimize global warming and has been commonly used to produce electricity. Because of their uncontrollable wind characteristics, wind speed forecasting is considered one of the best challenges in developing power generation. The Autoregressive Integrated Moving Average (ARIMA), Simple Exponential Smoothing (SES) and a hybrid model combination of ARIMA and SES will be used in this study to predict the wind speed. The mean absolute percentage error (MAPE) and the root mean square error (RMSE) are used as measurement of efficiency. The hybrid model provides a positive outcome for predicting wind speed compare to the single model of ARIMA and SES

    Effects of holes radius on plasmonic photonic crystal fiber sensor with internal gold layer

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    In this study, a plasmonic photonic crystal fiber (PCF) sensor was designed with an internal gold layer between the liquid holes and the air holes. The study shown that the thickness of the gold layer, the radius of the air holes and the radius of the liquid holes all have a significant effect on the sensitivity of the sensor, where a wavelength sensitivity of (10,500 nm/RIU) was achieved at certain simulation conditions. Under these chosen conditions, the relationship of resonance wavelength with the refractive index of the liquid was linear and this gives flexibility to extend the range of the refractive index of the analyte without changing the sensor design. Approaching or moving away of the holes from center in the proposed design has a fundamental role in determining the sensor characteristics

    Studying The Optical Properties of CdO and CdO: Bi Thin Films

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    Cadmium Oxide and Bi doped Cadmium Oxide thin films are prepared by using the chemical spray pyrolysis technique a glass substrate at a temperature of (400?C) with volumetric concentration (2,4)%. The thickness of all prepared films is about (400±20) nm. Transmittance and Absorbance spectra are recorded in the wave length ranged (400-800) nm. The nature of electronic transitions is determined, it is found out that these films have directly allowed transition with an optical energy gap of (2.37( eV for CdO and ) 2.59, 2.62) eV for (2% ,4%) Bi doped CdO respectively. The optical constants have been evaluated before and after doping

    The Rights of Prisoners in Nigeria and the Role of Prisons and Modern Penology

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    Prison system in Nigeria and elsewhere not only disables its inmates from their criminal pursuit but equally serves as an institution for their reform and rehabilitation into the society after their release. The system of imprisonment represents a curious combination of different objectives of punishment. The attitude of society towards prisoners may vary according to the objects of imprisonment and social reaction to the crime. Whereas rigorous imprisonment and imposition of severe restriction on the prisoner signifies retribution or deterrence, a lesser restriction and control over him in the form of simple imprisonment means that he is considered to be only a deviant. The modern progressive view, however regards crime as a social disease and favours treatment of offenders through non-penal methods such as probation, parole, open jail etc. Whatever be the reaction of society to the crime, the lodging of criminals in prisons gives rise to several problems of correction, rehabilitation and reformation. It may equally constitute serious violation of prisoners’ rights as they are also human-not devoid of their rights

    Audit of Radiology Request Cards in a Tertiary Hospital in NorthWest Nigeria

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      Background: Radiology request cards are essential communication tools between physicians and  radiation personnel. Clinical audit is part of quality assurance that guarantees patient care. Objective:  To assess the adequacy of patient data and clinical information filled in request cards sent to Radiology Department of our facility by referring clinicians. Material and methods: Four hundred (400) radiology request cards were randomly selected from the records of the department and scrutinized for bio-data/clinical information. Result: Completely filled request cards were 2/267 (ultrasound), 1/40 (computed tomography) and  2/93 (conventional x-ray).  Conclusion: Consistency in complete filliing of radiology request cards in our facility was lacking. The audit revealed actual practice, and the need for improvement.    &nbsp

    Characterization of flow rate and Heat Loss in Heating, Ventilation and Air Conditioning (HVAC) Duct System for Office Building

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    A building is an assemblage that is firmly attached to the ground and provides the performance of human activities and need to be considered in the daily operation in that building. The improvements in building performance are focused on improving the energy efficiency of buildings. This is approach by designing heating, ventilation and air conditioning (HVAC) duct system due to one of the most utilized energy in maintaining building performance and environment. The objectives of this research is to calculate the air (CFM) supply in office building, to characterize the velocity and head loss in a round and rectangular HVAC ducting system at various duct thickness and to optimize the thickness of the duct in HVAC system according to ASHRAE Standard. The increasing of velocity in duct system shows the increasing of head loss. The round duct design gives the lowest velocity and head loss in HVAC system approximately around 9.35% as compared to rectangular duct at 0.06 inches thickness. Hence, the trends of the head loss and duct thickness has influenced in reducing noise in HVAC duct system in order to select the best design concepts which is round shape design
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