Department of Chemical and Process Systems Engineering

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Synthesis of Oligomers of 12-Acryloyloxydodecanoic Acid via Reversible Addition Fragmentation Transfer (RAFT) Polymerisation
(International Journal of Chemistry, 2009-08-05) Tichagwa, Lilian; Sanderson, Ron; Pasch, Harald
A long chain fatty acid carrying an acryloyl functionality, 12-acryloyloxydodecanoic acid (12-ADA), was prepared from 11-hydroxydodecanoic acid and acryloyl chloride and used as monomer in the synthesis of oligomers of 12-ADA via the RAFT controlled polymerisation process. Reversible Addition Fragmentation Transfer (RAFT) reagents were prepared and used to control the polymerisation process and produced an oligomeric product with few monomeric units instead of a high molecular weight polymer of 12-ADA. The transfer reagents were prepared from Grignar intermediates from a reaction of dithioacids with free radical initiators 2,2-azobisisobutyronitrile (AIBN) and 4,4-azobis(4-cyanopropanoic acid) (ACP). It was found that short-chain oligomers in the form of dimers and trimers characterized by Electrospray Mass Spectrometry, ESMS and Gel Permeation chromatography, GPC were the major products obtained when RAFT reagents had been used in the controlled polymerisation. As a control, polymerisation was carried out in the absence of RAFT reagents and high molecular-weight polymers were obtained. This confirmed the effectiveness of the prepared RAFT reagents as polymerisation controllers and provided a way for the synthesis of oligomers. Here, the preparation of oligomers of 12-ADA using AIBN-RAFT reagents is reported. The method is expected to provide one way of preparing oligomers of controlled chain length/molecular mass which also carry a carboxylic acid functional group at one end.
Vermicompostingof Waste Corn Pulp Blended with Cow Dung Manure using Eisenia Fetida
(World Academy of Science, Engineering and Technology, 2012-02-06) Musaida M. M., Manyuchi; Anthony, Phiri; Perkins, Muredzi,; Joseph, Govhaand; Thamary, Sengudzwa
Waste corn pulp was investigated as a potential feedstock during vermicomposting using Eisenia fetida. Corn pulp is the major staple food in Southern Africa and constitutes about 25% of the total organic waste. Wastecooked corn pulp was blended with cow dung in the ratio 6:1 respectively to optimize the vermicomposting process. The feedstock was allowed to vermicompost for 30 days. The vermicomposting took place in a 3- tray plastic worm bin. Moisture content, temperature, pH, and electrical conductivity were monitoreddaily. The NPK content was determined at day 30. During vermicomposting, moisture content increased from 27.68% to 52.41%, temperature ranged between 19- 25◦C, pH increased from 5.5 to 7.7, and electrical conductivity decreased from 80000µS/cm to 60000µS/cm. The ash content increased from 11.40% to 28.15%; additionally the volatile matter increased from 1.45% to 10.02%. An odorless, dark brown vermicompost was obtained. The vermicompost NPK content was 4.19%, 1.15%, and 6.18% respectively.
Adsorption of Methyl Orange, Pb2þ and Cd2þ from Aqueous Solution by Composites of LignocelluloseMontmorillonite Modified with Methacryloxypropyl Trimethoxysilane
(WILEY-VCH Verlag GmbH & Co. KGaA,, 2012-03-07) Tavengwa, Bunhu; Lilian, Tichagwa
A composite material based on lignocellulose and montmorillonite clay (MPSgLig-NaMMT) was prepared and evaluated as an adsorbent for the removal of pollutants (dyes and heavy metals) from aqueous solution. The lignocellulosemontmorillonite composite was prepared by in situ intercalative polymerisation, using methacryloxypropyl trimethoxysilane (MPS) as a coupling agent. The composite material was characterised by FTIR, TGA and SAXS. The lignocellulose-montmorillonite composite was assessed as an adsorbent for methyl orange dye from aqueous solution. The composite material showed enhanced adsorption of methyl orange (MetO) compared with the NaMMT or lignocellulose separately. Competitive adsorption studies were carried out from binary mixtures of MetO with Cd2þ or Pb2þ in aqueous solution. The adsorption process of MetO onto the composite material was found to follow the Freundlich adsorption model. The adsorption of methyl orange from binary mixtures, were found to follow both the pseudo first-order and pseudo second-order models
A hybrid support vector machine and fuzzy reasoning based fault diagnosis and rescue system for stable glutamate fermentation
(Elsevier, 2012-09-09) Jian, Ding; Yan, Cao; Enock, Mpofu; Zhongping, Shi
In industrial glutamate fermentation by biotin-auxotroph Corynebacterium glutamicum, biotin content variation in corn slurry greatly affects fermentation performance. To maintain the fermentation stability, a hybrid support vector machine (SVM) and fuzzy reasoning based fault diagnosis and rescue system was developed. The system uses SVM outputs as the inputs of the fuzzy reasoning classifier having a couple of production rules and condition membership functions related with SVM outputs, to categorize multiple faults. The effectiveness of the proposed system was verified in a normal fermentation run and two abnormal runs with different biotin initial-content faults with the aid of using on-line measurable data such as ammonia consumption rate and CO2 evolution rate. The results indicated that the proposed faults-diagnosis system could cluster multiple fermentation faults quickly, accurately and stably, and faults and their types could be identified at the earliest fermentation stage. Based on the diagnosis results, the proposed system was further applied for real fault-rescue in two fermentations with different biotin initial-content faults. In both cases, by immediately taking relevant rescue measures after identifying the faults and their types, glutamate fermentations with initial faults were restored to normal, and final glutamate concentrations reached a normal level of 75–80 g/L at 34h.
Design of a material handling system that feeds bagged powder into polyvinyl acetate paint disperser as a Cleaner Production option
(International Journal of Scientific & Engineering Research, 2012-12-05) Winnie, Mutenhabundo,; Ngoni, Chirinda,; Tauyanashe, Chikuku
This project is about designing a material handling system that feeds bagged powder into the disperser as a Cleaner Production, (CP) option. Initially, waste streams were identified; the levels of dust emissions were assessed as well as their impacts to humans and environment. The researchers set their objectives seeking to reduce these negative effects. Attempts were made to recognize potential sources of airborne dust using Cleaner Production Assessment and assess the dust load upon workers in several process stages by comparing observations with standard values assigned by American Conference of Governmental Industrial Hygiene, (ACGIH). Loading pigment material generates dust which can cause serious health problems as reported in Material Safety Data Sheets. The new technology option of CP in form of a design led to a reduction in dust emissions thus reducing potential health hazards and also a reduction in material consumption. The researchers therefore recommend this design to enable Cleaner Production.
Design of a waste management model using integrated solid waste management: A case of Bulawayo City Council
(International Journal of Water Resources and Environmental Engineering, 2013-01-21) Mwanza, Bupe; Phiri, Anthony
The purpose of this research paper was to design a waste management model for Bulawayo City Council (BCC) based on integrated solid waste management system. The increasing solid waste generation in the city of Bulawayo is evidenced by increased number of illegal dumping of waste in the urban communities. In this paper, a model that identifies cost-effective and efficient combinations of scientific and engineering tools to manage solid waste and also incorporating the key performance indicators (KPIs) or metrics for solid waste management services has been designed. Literature on different types of waste management models, quantitative analysis of waste at Ross camp, direct observations made in the city locations and policy documents of the Zimbabwean Government (EMA acts), founded the development of this model. The design shows a clear depiction of the environmental management acts (EMA) and the municipality by-laws. Performance measurement which is very critical in waste management has been incorporated. Model design focus was on waste type which is a determinant of the waste receptacles, collection, transportation and disposal methods have therefore been depicted in the model. The model provides easy access to data for the formation and implementation of effective solid waste management policies, strategies and programs to achieve sustainable waste management.
Vermifiltration of Sewage Wastewater for Potential Use in Irrigation Purposes Using Eisenia fetida Earthworms
(World Academy of Science, Engineering and Technology, 2013-02-05) Manyuchi, Musaida Mercy; Boka, Simbarashe; Kadzungura, Luckmore
—Vermifiltration was used for treatment of sewage wastewater using the Eisenia fetida earthworm species. The earthworms’ gut acted as a bioreactor and they reduced the sewage wastewater solid and liquid organic wastes through ingestion and expelling these as vermicompost. 500 earthworms were used in the vermifilter over a 5 period of days. The treated water pH increased from being acidic to neutral. The sewage wastewater biological oxygen demand (BOD5), chemical oxygen demand (COD), total dissolved and soluble solids (TDSS) and turbidity decreased by 98%, 70%, 95% and 98% respectively through vermifiltration. Vermifiltration significantly decreased the sewage water physicochemical parameters compared to an ordinary bio-filter without earthworms. The vermi-treated sewage water compared well with the set standards for irrigation water. Vermifiltration technology can therefore be applied as an environmentally friendly technique for sewage water treatment for irrigation purposes
Pilot Scale Studies for Vermifiltration of 1000m3 /day of Sewage Wastewater
(Asian Journal of Engineering and Technology, 2013-03-01) Manyuchi, Musaida Mercy; Kadzungura, Luckmore; Boka, Sandra
Vermifiltration is a technology in which the combined action of earthworms’ activity and theabsorption properties of soil, sand and gravel particles on the organic pollutants are applied for wastewater treatment. Vermifiltration was used in sewage wastewater treatment as a cheaper and enviro-friendly technology. 1000m3 /day of sewage wastewater was treated in a four layered vermifilter at an Eisenia fetida earthworm density of 8 000 earthworms/m2 in a 3.6m2 soil bed. The vermifilter bed layers comprised of 4-8mm garden soil particles, 8-12mm mixed sand and gravel particles, 30-50mm small aggregates and 70-80mm large aggregates respectively. A vermifilter bed porosity of 0.96 was used. The vermifilter had a hydraulic retention time of 0.082days and a hydraulic loadingrate of 0.93m3/m2.day. The vermifilter design effectively resulted in over 90% reduction in BOD, COD, TDSS andturbidity as well as neutralized pH in the sewage wastewater. Proper vermifilter design ensures optimum sewage wastewater treatment for potential use in irrigation
Effects of soya bean meal feed properties on extrusion failures and implementing a solution.
(International Journal of Nutrition and Food Sciences 2013; 2(2) : 60-69 Published online March 10, 2013 (http://www.sciencepublishinggroup.com/j/ijnfs) doi: 10.11648/j.ijnfs.20130202.16, 2013-03-10) Muredzi, Perkins; Nyahada, Moses; Mashswa, B.W
This research was a contribution on the optimization of extrusion process by determining the effects of feed properties on extrusion failures and implementing a solution. The objectives of the research were to increase the set soy meal to chunk conversion standard from 65% to 80%; to determine the effects of feed properties on extrusion failures; to determine the best conditions of the feed properties that promote an effective extrusion cooking process; and to determine a solution of optimizing these feed properties for successful extrusion. The research was company based and it followed the failures of extrusion experienced at Monmouth Path Investment (Pvt) Ltd in Waterfall, Harare. This research was limited to feed properties such as fat content, moisture content and particle size as the factors that cause extrusion failures. The determination of moisture content was done by using a moisture analyzer, fat content was determined through the Soxhlet method and the particle size of the feed was determined through sieve analysis. The results revealed that extrusion process was most successful when the soy meals fat content was greater than 6.0%, with a moisture content less than 6.0% and particle size range of 0.95-1.0mm. The process of optimization of extrusion process was solved by designing an extrusion calculator and blending ratio factors. The objective of determining the effects of feed properties on extrusion failures was achieved as well as that of implementing a solution. The objective of increasing Monmouth Path’s standard soy meal/chunk conversion was partially achieved since the implemented solution is not yet measurable.
Continuous flow-through vermireactor for medium scale vermicomposting
(Asian Journal of Engineering and Technology, 2013-04-01) Manyuchi, Musaida Mercy; Chitambwe, Trymore; Chigumo, Michelle T. C.; Phiri, Anthony; Muredzi, Perkins; Kanhukamwe, Quinton
Vermicomposting is increasingly becoming popular as an organic waste management technology whereby earthworms feed on the organic waste to produce vermicasts and vermiwash. Several vermireactors have been used for this process as batch systems. However, there is need to design a continuous flow-through vermireactor which allows the simultaneous addition of the organic waste at the same time harvesting the vermicasts. A 5m X 2m X 1.5m vermireactor was proposed to process an initial feed of 7 500kg. A 10cm thick bedding comprising of office paper, card board paper and Eisenia fetida earthworms stocked at 1kg/m2 of the vermireactor was used as an initial bedding. The feed bed was 20cm thick and comprised of paper, cow dung, corn pulp and vegetables. The pH, temperature and moisture content in the vermireactor ranged between 5.5-7.5, 19-25°C and 28-52% respectively. 7kg/day of vermicasts were produced given the earthworms produced 75% of their bodyweight as vermicasts per day. The caked vermicasts were expelled by the aid of a breaker bar. The vermireactor was constructed from polyvinyl chloride. Vermicasts containing nitrogen (4.19%), phosphorous(1.15%) and potassium (6.18%) were obtained. The continuous flow-through vermireactor design allowed the production of stable vermicasts and can be used in medium scale vermicomposting.
Cleaner Production options in sand casting in foundries.
(International Journal of Sustainable Energy and Environment, 2013-04-06) Masike, Rujeko; Chimbadzwa, M.J
The purpose of this paper was to assist foundries in pollution prevention by devising clean technologies which maintain or improve the quality of the ambient surrounding. The paper used Cleaner Production and its opportunities to minimize material consumption, optimize production yield and to prevent polluting the air, water and land. The reseachers reviewed how sand casting foundries can implement Cleaner Production and benefit from the created conducive environment as well as saved financial capital. The review gave an overview of the environmental aspects and impacts of foundry operations. It also outlined best practices to improve the energy, material, and environmental efficiency, and the product output of the operation. The current environmental status and performance of foundry companies in Zimbabwe was determined from the initial environmental review, energy and environmental audits. Once the environmental status was established, Cleaner Production options were then modelled. The feasibility of the options were also analysed, and life cycle analysis of casted products was carried out. The researchers concluded that raw materials, water, and energy were to be saved if foundry companies implemented Cleaner Production options.
Effect of Vermicompost, Vermiwash and Application Time on Soil Micronutrients Composition
(International Journal of Engineering and Advanced Technology (IJEAT), 2013-06-03) Manyuchi, Musaida Mercy; Phiri, Anthony; Muredzi, Perkins
Vermicomposting is increasingly becoming popular as an organic solid waste management strategy. The technology results in two bio-fertilizers, vermicompost and vermiwash. The bio-fertilizers were applied to the soil and their impact on the soil micronutrients time was quantified. A maximum of 1000g of vermicompost and vermiwash was applied over 40 days. 23 factorial designs were used to determine the effects of the bio-fertilizers and application time on the soil micronutrients. Increasing the vermicompost quantity resulted in increased soil zinc, manganese and iron content. Increased vermiwash quantities resulted in increased soil iron content but resulted in decreased copper content. Furthermore, increased application time of the two bio-fertilizers resulted in enhanced soil copper and iron content but decreased the zinc and manganese content. The loam-clay soil, organic material from the bio-fertilizers and microbial activity played a significant role in altering the soil micronutrients.
Comparison of Vermicompost and Vermiwash Bio-fertilizers from Vermicomposting Waste Corn Pulp
(World Academy of Science, Engineering and Technology, 2013-07-07) Phiri, A; Muredzi, P; Manyuchi, M.M; Chitambwe, T
—Vermicomposting is the conversion of organic waste into bio-fertilizers through the action of earthworm. This technology is widely used for organic solid waste management. Waste corn pulp blended with cow dung manure was vermicomposted over 30 days using Eisenia fetida earthworms species. pH, temperature, moisture content, and electrical conductivity were daily monitored. The feedstock, vermicompost and vermiwash were analyzed for nutrient composition. The average temperature and moisture content in the vermi-reactor was 22.5◦C and 42.5% respectively. The vermicompost and vermiwash had an almost neutral pH whilst the electrical conductivity was 21% higher in the vermicompost. The nitrogen and potassium content was 57% and 79.6% richer in the vermicompost respectively compared to the vermiwash. However, the vermiwash was 84% richer in phosphorous as compared to vermicompost. Furthermore, the vermiwash was 89.1% and 97.6% richer in Ca and Mg respectively and was 97.8% richer in Na salts compared to the vermicompost. The vermiwash also indicated a significantly higher amount of micronutrients. Both bio-fertilizers were rich in nutrients specification for fertilizers.
Effect of Vermicompost, Vermiwash and Application Time on Soil Physicochemical Properties
(International Journal of Chemical and Environmental Engineering, 2013-08-01) Manyuchi, Musaida Mercy; Chitambwe, Trymore; Phiri, Anthony; Muredzi, Perkins; Kanhukamwe, Quinton
Vermicomposting results in the production of two bio-fertilizers, vermicompost and vermiwash. The bio-fertilizers were applied to 4kg of loam-clay soil over a period of 40 days. The effect of the vermicompost, vermiwash, application time and their combined effect on soil pH, electrical conductivity and nitrogen, phosphorous and potassium content were analyzed. Increasing the vermicompost quantity decreased the soil pH, electrical conductivity and nitrogen content, however, this resulted in a slight increase in the phosphorous content but the potassium content remained unaltered. Increasing the vermiwash quantity increased the soil pH, electrical conductivity and potassium content but resulted in reduced nitrogen and phosphorous content. In addition, increasing the application period of either the vermicompost or the vermiwash resulted in increased soil pH, electrical conductivity, phosphorous and potassium content but resulted in reduced phosphorous content. The reduction of the soil nitrogen content is attributed to de-nitrification, whilst the increase in phosphorous content is attributed to increase in soluble phosphates and release of nutrients into the soil due to microbial activity in the bio-fertilizers. Furthermore, loam-clay soils have good absorbing properties for potassium. The soil properties and micro-organisms present in the bio-fertilizers play a critical role on the modification of the soil physicochemical properties
Effective Separation of Vermicasts fromEarthworms Using a Cylindrical Rotary Trommel Separator
(International Journal of Innovative Research in Science, Engineering and Technology, 2013-08-02) Manyuchi, Musaida Mercy; Phiri, Anthony
Vermicomposting technology is widely being used worldwide as a solid waste management strategy. During vermicomposting Eisenia fetida earthworms ingest the solid organic waste and after a bioconversion process it is expelled as vermicasts. These vermicasts can be used as solid bio-fertilizers; however there are challenges of separating the earthworms from the vermicasts after vermicomposting. Pilot studies were therefore done using a cylindrical rotary trommel screen separator prototype to efficiently separate the earthworms from the vermicasts. The vermicasts were obtained from vermicomposting waste corn pulp mixed with cow dung manure and waste office paper. The cylindrical rotary screen had a mesh size of 4 mm, length of 250 mm and diameter of 90 mm. A throughput of 1.3 m3 /hr comprising of vermicasts and earthworms with a moisture content of 40-60% was separated trommel screen rotational speeds of 30-70rpm. The vermicasts separation efficient was around 80-95% but optimum separation of 95% was achieved at 40% moisture content and trommel screen rotational speed of 50rpm. Using a mechanical trommel screen separator increased the separation of vermicasts and earthworms, hence making the vermicomposting technology ideal.
Women in Engineering for Economy Recovery in Zimbabwe
(Asian Journal of Business and Management, 2013-08-03) Manyuchi, Musaida Mercy
Engineering is the application of scientific and mathematical knowledge as well as creativity for the development of solutions as well as for technology advancement. Previously the engineering field has been male dominated but of late women are taking up this discipline although the rate is still as low as 25%. The low uptake of these engineering fields by women therefore affects the output of women engineers into the society and consequently therefore failure to meet the engineering demands of our country. However, due to the women friendly policy implementation in Zimbabwe, involvement by women in engineering is increasing. Women engineers are helping ease problems of special skills shortage as well as lowering the gender imbalance that has existed in this field. Furthermore, participation by women engineers minimizes the employment shortage as well as re-boosting the economy in all fields such as academia, industry and entrepreneurship. Women engineers on the ground are working hard participating in the economic recovery of Zimbabwe but, there is need for more for an effective change. This is achievable through awareness campaigns and implementation of policies crafted to empower women.
Friction Stir Welding of steels:
(IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE), 2013-09-05) Kudzanayi, Chiteka
Friction Stir Welding (FSW) is a solid state joining process that can be applied to a number of materials including aluminium, magnesium, copper and steels. A number of researches have been conducted in Friction Stir Welding of steels and it is the focus of this paper to make a comprehensive review of the work that has been done. Ultra-low carbon steels, low carbon steels, medium carbon steels, high carbon steels and ultrahigh carbon steels have been considered and several aspects of FSW of steels have been outlined. These are tools, mechanical properties and microstructure. It was determined that carbon content, welding speed as well as rotational speed affect both mechanical properties and microstructure of the joint.
Effect of Drying on Vermicompost Macronutrient Composition
(International Journal of Inventive Engineering and Sciences (IJIES), 2013-09-05) Manyuchi, M.M; Phiri, A; Muredzi, Perkins; Chirinda, N
Vermicomposting is widely being used for bio-conversion of organic wastes into bio-fertilizers. Vermicompost which was obtained from various food wastes was dried at 105◦C for 5 minutes in a moisture analyzer. The dried vermicompost macronutrient composition was analyzed and quantified over the raw vermicompost. The dried vermicompost total nitrogen content was 31.25% lower as compared to the raw vermicompost whereas , the phosphorous and potassium content were 63.75% and 72.86% higher in the dried vermicompost compared to the raw vermicompost respectively. Vermicompost can be dried for easier packaging, storage and transportation as the drying process in overall enhances nutritional value to the vermicompost
Bio-conversion of Food Wastes into Vermicompost and Vermiwash
(International Journal of Science and Modern Engineering (IJISME), 2013-09-10) Manyuchi, Mercy; Phiri, Anthony; Muredzi, Perkins; Chirinda, Ngoni
Vermicomposting technology is the bio-conversion of organic waste into bio-fertilizers using earthworms. Vermicomposting is widely being used for solid waste management. Various food wastes were vermicomposted over 30 days using Eisenia fetida earthworms. Vermicompost and vermiwash were obtained as vermi-products. The vermicompost nitrogen, phosphorous and potassium composition was 2.1%, 0.29% and 0.19% respectively. Whereas, the vermiwash only contained 0.58% nitrogen and 0.47% potassium. Vermicomposting technology is necessary as a food wastes management strategy.
Impact of Vermicompost on Lettuce Cultivated Soil
(International Journal of Inventive Engineering and Sciences (IJIES), 2013-10-02) Manyuchi, Musaida Mercy; Mudamburi, T; Phiri, Anthony; Muredzi, Perkins
— Vermicomposting is an environmentally friendly technique that is used for organic solid waste management. Waste corn pulp blended with cow dung and office paper was vermicomposted over 30 days to produce vermicompost which is a bio-fertilizer. The vermicompost was applied to soil cultivated with lettuce at the planting and after every four weeks. The impact of vermicompost on the soil was quantified. Application of vermicompost resulted in a 5%, 21.7%, 16.9% and 4.92% increase in soil pH, nitrogen, phosphorous and manganese content respectively. Application of the vermicompost also resulted in a 9.41% and 3.77% decrease in soil electrical conductivity and potassium content respectively. However, application of vermicompost did not alter the copper and zinc content of the lettuce cultivated soil. The lettuce showed vigor and vitality during the period of growth. Vermicompost can be used for sustainable agriculture practices