Numerical approximation of second-order boundary value problems via hybrid boundary value method

Hybrid Boundary Value Method (HyBVM) is a new scheme, which is based on Linear Multistep Method (LMM). The HyBVM is the hybrid version of the Boundary Value Methods (BVMs) which are methods derived to overcome the limitations of the LMMs. This new scheme shares the same characteristic with the Runge Kutta method as data are utilized at off-step points. In this work, we apply this method to two second order Boundary Value Problems (BVPs) with mixed boundary conditions and the results are efficient when compared to other BVMs in literature

Application of Mass Transfer in the Pulp and Paper Industry− Overview, Processing, Challenges, and Prospects

This study reviews the mass transfer with a focus on the challenges, benefits, processing and prospects in the pulp and paper industry with a scope limited to Kraft pulping which is the dominant pulping process worldwide. The mass transfer usually occurs in various processes that deal with reactions, separation, and heat transfer. All these aforementioned processes occur in the production of pulp and paper from their raw materials. The application of mass transfer to these processes is of great importance in setting target yields, and specifications and improving efficiency. The major processes where mass transfer principles are applied are drying, chemical washing, pulp digestion and pulp bleaching respectively. Understanding the requirements and targets of each of these processes in combination with the mass transfer principles helps in the development of models and design of equipment that operate based on the developed models in meeting the required targets. Studies have indicated that mass and energy balances cannot be done independently in meeting the required targets and equipment design. The drying and stripping of lignocellulosic components of the feed-in paper manufacture constitute a large part of the challenges faced by the industry. Drying techniques have been considered to be inefficient, and lignocellulosic by-products are known to contain toxic components. Green chemistry production processes and newer drying techniques were indicated as possible solutions. It is expected that researchers and investors would find this article useful

DISPERSION MODELLING OF PARTICULATE EMISSION FROM OFF-GRID DIESEL ENGINE ELECTRIC POWER GENERATORS

Emission inventories and ISC-Aermod dispersion modeling tool were used to investigate the impacts of particulate matter (PM) emission from off-grid electric power generators used by a textile factory on ambient air quality (AAQ) of the immediate and distant environment of the plant. Information on diesel consumption obtained from the factory was combined with emission factor of diesel powered generators to obtain the emission rates of PM. The emission rates, meteorological parameters, terrain grid and output pathways were inputed into the ISC-Aermod dispersion modeling tool to obtain the ground level concentrations (GLC) of PM. The maximum GLCs were compared with AAQ limit of 250 μg/m3 set for PM by Nigeria’s Federal Ministry of Environment to establish their impacts. Results showed that worst case scenario (WCS) gave PM concentrations of 1.4 – 17.8 μg/m3 and 0.1 – 6.8 μg/m3 for 1-hr and 24-hrs averaging period respectively. The predicted impact using the WCS showed that the ambient PM of the host air shed changed by 0.1 - 1.2% of FMENV standard. It was concluded that emissions from factory would not significantly affect the ambient PM of the host air shed

Modelling of sweet gas flaring and the resultant gaseous emissions with their emission factors

Data from literature and a stoichiometric material balance model were employed to estimate associated emissions with flaring of sweet gas in Nigerian oil and gas companies. Emission factors were obtained using AP 42 formula. Results showed that thousands of tonnes, ranging from 6500 to 22,000 tonnes of natural gas were flared from 1997 to 2016. At flaring stack efficiencies of 97% and 98%, the associated emissions are: CH4, C2H6, C3H8, iC4H10, nC4H10, iC5H12, nC5H12, C6H14, C7H16, C8H18, C9H20, CO2, and N2 from unburnt natural gas and in addition to CO2, CO, N2, NO, NO2, H2O and H2 from incomplete combustion. At both flaring stack efficiencies, the amount of emissions from unburnt condition ranged from1,608 tonnes N2 to 9,146 tonnes CO2 all higher than any emission standards in the world, while the amounts of emissions from incomplete combustion ranged from 467,964 tonnes for CO2 the lowest to 2,476,011 tonnes for N2 the highest all higher than any emission standards in the globe. Emission factors of emissions from unburnt natural gas ranged from 0.000090 tonne/tonne for C10H22 to 0.026235 tonne/tonne for CH4 while those of the emissions from incomplete combustion ranged from 0.10285 tonne/tonne for H2 to 1.13137 for CO2 tonne/tonne. It was observed that thousands of tonnes of emissions are released into the atmosphere during flaring of sweet natural gas either at complete or incomplete combustion. It is recommended that flaring of natural gas should be reduced to a minimal level to safeguard the environment

The effect of air-fuel ratio on tailpipe exhaust emission of motorcycles

This article presents the actual AFR of the vehicular emission from the tailpipe data of motorcycles with petrol engine in Southwest Nigeria. It also presents the ratio between the actual air-fuel ratio (AFRactual) and the ideal/ stoichiometric air-fuel ratio (AFRideal) known as the equivalence air-fuel ratio or lambda (λ). This was compared with the expected value for lambda by the catalytic technology for exhaust gases emission, which is 1 (± 5%). In this study, over 95% of the sampled motorcycles have higher lambda values than expected, thereby emitting very high concentrations of carbon monoxide (CO), hydrocarbon (HC), and carbon dioxide (CO2). The Portable, Hand- Held, battery-operated Kane automotive 4-gas analyser with detector tube (Model Auto 4-1) was used to measure the automobile emissions. The air-fuel ratio is a significant indicator and very important measure for gasoline engine performance controlling and tuning, and anti vehicles exhaust emissions pollution reasons [1]. Internal combustion (IC) gasoline fuelled engines exhaust gases emission depend heavily and mainly on the air-fuel ratio. For a gasoline fuelled engine, carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) exhaust gases emission are significantly influenced by air-fuel ratio. CO and HC are majorly generated or produced with rich air–fuel mixture, while NOx with lean air-fuel mixtures which mean that there is no fixed air-fuel mixture for which it can obtain the minimum for all exhaust gases emission [2]. This study can help in reducing fuel consumption, improving the quality of fuel combustion and reducing vehicle exhaust emissions in Nigeria

A COMPARATIVE ANALYSIS ON THE CLARIFICATION EFFICIENCY OF LIME AND MORINGA OLEIFERA ON CANE SUGAR JUICE

A comparative analysis of the clarification efficiency of lime and moringaoleifera on cane sugar juice was investigated. Moringa pods were collected and their seeds ground into powder. The seed oil was extracted using a crude method. Calcium oxide and moringaoleifera seed cake were used to effect colloid coagulation in sugarcane juice. The dosages by weight were varied. The settling time was also varied. Clarification was measured as a function of absorbance. The absorbance was measured at different wavelengths. A wavelength of 600nm was used in the results and discussion. The absorbance of the clarified sugarcane juice over a period of five hours was obtained. A cost analysis was also investigated. The results suggest that Moringaoleifera is a more efficient coagulating aid at 1g Moringa/100ml of sugarcane juice with an absorbance of 1.803 after one hour although calcium oxide (lime) is cheaper

ASSESSMENT OF THE POTENTIAL EMISSIONSFROM BIODIESEL PRODUCED FROM GROUNDNUT AND SOYBEAN OILS

Biodiesel an alternative fuel to fossil fuel) does not only require production at commercial level, but the production process also needs to be a clean and environmental friendly. This research aim at assessing the potential emissions form the biodiesel produced from the trans-esterification of groundnut oil and soybean oil, using KOH homogenous catalyst. The impact assessment of the potential emissions wasanalysed, quantified and characterized using Simapro 8.2.3.0. Comparatively, soybean biodiesel produced higher yield of biodiesel compare to yield obtained from groundnut oil biodiesel, under same experimental conditions. Also, high yields of biodiesel observed (97.1 % using both soybean oil and 92.1 % using groundnut oil) were at experimental conditions of 52.5oC and catalyst concentration 0.9 wt/wt%, at constant methanol/oil mole ratio of 6 and reaction time of 1 hour. The impact assessment of the emissions from the biodiesels obtained from the two oils revealed that groundnut oil biodiesel has the potential to release more fresh water toxic substances, terrestrial toxic substances and human toxic substances

ASSESSMENT OF CARBON MONOXIDE EMISSION FROM DIFFERENT BRANDS OF SPLIT AIR-CONDITIONERS

The detection and assessment of pollutants emitted from electrical appliances has become a great area of interest to environmentalists as a means of being aware of the sources which contribute to the outdoor air quality. In this study, carbon monoxide emission was assessed from the source, which was the outdoor unit of working split air-conditioners. Five (5) brands (B1, B2, B3, B4 and B5) of twenty-five (25) split airconditioners prominent in Covenant University were selected, five split airconditioners per brand. The exhaust air from the outdoor unit was monitored for one (1) hour at two (2) minute intervals using the GM8805 Benetech carbon monoxide monitor. The data obtained were analysed and the daily mean, weekly mean, monthly mean and yearly mean contributions of each brand to the ambient carbon monoxide emission were determined. The results of individual contributions to ambient carbon monoxide emission, on yearly basis, obtained were: 35376 ppm for brand 1 (B1), 57552 ppm for brand 2 (B2), 54384 ppm for brand 3 (B3), 115632 ppm brand 4 (B4) and 672144 ppm for brand 5 (B5). The air conditioner with the highest contribution to ambient carbon monoxide concentrations was B5 at 672144 ppm on a yearly basis. It was concluded that split air-conditioners also contribute emissions into ambient air

Assessment of environmental impact of telecommunication base transceivers stations in residential areas

This paper assessed the environmental impact of a telecommunication base transceiver stations (BTS) located at Cardoso Close, Apapa, Lagos State, Nigeria with the coordinates 6o4392’N, 3o3126’E. The ambient air quality parameters: SO2, NO, CO, CH4 and total suspended particulates (TSP) were measured using the ITX Emission Analyzer at four sampling points within the base station. The concentrations of SO2, NO, CO and TSP atthe base station ranged between 0.3-0.5 ppm, 1.9-2.2 ppm, 5.5-7.5 ppm, 101-110 μg/m3 respectively for 24-hour averaging period. CH4 was not detected at any of the sampling points. A digital Realistic Sound Level Meter was used in measuring the noise level. The measured average noise levels in all the four sampling points at the BTS studied ranged between 83.1- 88.7 dB (A). Samples of water were collected from boreholes around the base station and were subjected tophysico-chemical examinations using the ‘standard methods for water and waste water’ 14th edition prepared by American Public Health Association (APHA). The analyses of the water samples showed that all the parameters are within limits. To measure the electromagnetic radiation emitted from the station during the field study, the SPECTRAN HF-4049 RF, an in-situ dosimeter for radio frequency measurement was used. The results obtained showed that, the measured averageradiation levels in all the four sampling points within the BTS studied ranged between 0.051-0.054 μW/m2. All the measured parameters are within safety margins apart from SO2 and NO. SO2 was not traceable to the BTS while NO was only partly connected with the fossil-fuelled electricity generating sets. The parameters of the physico-chemical analysis of the borehole water were significantly below limits