Effects of total aqueous extracts of Mallotus oppositifolium and Euphorbia hirta (Euphorbiaceae) on intestinal contractile activity of the rat. - The contractile activity of the total aqueous extract of Mallotus oppositifolium (Mo) and Euphorbia hirta (Eh) leaves was investigated. Mo extracts (1.32 mg/mL) demonstrated inhibiting effect on the stimulation of rat ileal contractions by acetylcholine (-9 mm) and potassium chloride (-7 mm). Administrated before the magnesium sulfate (6 g/kg), Mo extracts reduce the faeces quantity (- 11g, p before the magnesium sulfate, the Eh aqueous extract reduced the quantity of faeces (-12 g, p spasmogenic effect in vitro and antidiarrhoeic effects in vivo
{"title":"Effets des extraits totaux aqueux de mallotus oppositifolium et de euphorbia hirta (euphorbiaceae) sur l’activite contractile intestinale du rat","authors":"R. Kamgang, R. Zintchem, T. Dimo, Mp Yewah","doi":"10.4314/AJST.V2I2.44664","DOIUrl":"https://doi.org/10.4314/AJST.V2I2.44664","url":null,"abstract":"Effects of total aqueous extracts of Mallotus oppositifolium and Euphorbia hirta (Euphorbiaceae) on intestinal contractile activity of the rat. - The contractile activity of the total aqueous extract of Mallotus oppositifolium (Mo) and Euphorbia hirta (Eh) leaves was investigated. Mo extracts (1.32 mg/mL) demonstrated inhibiting effect on the stimulation of rat ileal contractions by acetylcholine (-9 mm) and potassium chloride (-7 mm). Administrated before the magnesium sulfate (6 g/kg), Mo extracts reduce the faeces quantity (- 11g, p before the magnesium sulfate, the Eh aqueous extract reduced the quantity of faeces (-12 g, p spasmogenic effect in vitro and antidiarrhoeic effects in vivo","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78501008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Freshly cut flowering stems of Alstroemeria ‘Yellow King’ and ‘Marina’ were placed in glass jars containing solutions of Accel at 0, 25, 50, 75 and 100 mg/litre BA equivalent and arranged in a completely randomised design with 3 replicates. The effect of Accel on the vase life and quality of Alstroemeria was investigated. Flowers held in Accel at 25 or 50 mg/litre BA equivalent consistently increased the number of days to full opening of primary florets and delayed the onset of flower senescence as measured by days to 50 % petal fall and days to 50 % leaf yellowing. Accel at 25mg/ litre BA equivalent significantly increased the leaf nitrogen and chlorophyll content of Alstroemeria cut flowers. High Accel concentrations of 50, 75 and 100 mg/litre BA equivalent reduced significantly the leaf water content of Alstroemeria cut flowers. Accel at 75 and 100 mg/litre BA equivalent increased leaf dry weight of Alstroemeria cut flowers. Our results indicate that Accel at 25 mg/litre BA equivalent has the potential to be used as a commercial cut flower preservative solution for delaying flower senescence, prolonging the vase life and enhancing post harvest quality of Alstroemeria cut flowers
将新剪下的Alstroemeria ' Yellow King '和' Marina '花茎放入玻璃罐中，罐中分别含有0、25、50、75和100 mg/l BA当量的Accel溶液，并按照完全随机设计，设置3个重复。研究了Accel对木耳瓶龄和品质的影响。在25或50毫克/升BA当量的浓度下，Accel中的花持续增加了初级小花完全开放的天数，并延迟了花衰老的开始，以花瓣掉落到50%的天数和叶子变黄到50%的天数来衡量。25mg/ l BA当量浓度的加速处理显著提高了桤木切花叶片氮和叶绿素含量。高浓度BA浓度分别为50、75和100 mg/l，显著降低了桤木切花叶片含水量。在75和100 mg/l BA当量浓度下，姜花切花叶片干重增加。本研究结果表明，25 mg/l BA当量的Accel可作为商品切花防腐液，具有延缓鲜花衰老、延长花瓶寿命和提高采收后品质的作用
{"title":"Effect of accel on the vase life and post harvest quality of alstroemeria (alstroemeria aurantiaca l.) cut flowers","authors":"T. M. Mutui, V. Emongor, M. Hutchinson","doi":"10.4314/AJST.V2I1.44650","DOIUrl":"https://doi.org/10.4314/AJST.V2I1.44650","url":null,"abstract":"Freshly cut flowering stems of Alstroemeria ‘Yellow King’ and ‘Marina’ were placed in glass jars containing solutions of Accel at 0, 25, 50, 75 and 100 mg/litre BA equivalent and arranged in a completely randomised design with 3 replicates. The effect of Accel on the vase life and quality of Alstroemeria was investigated. Flowers held in Accel at 25 or 50 mg/litre BA equivalent consistently increased the number of days to full opening of primary florets and delayed the onset of flower senescence as measured by days to 50 % petal fall and days to 50 % leaf yellowing. Accel at 25mg/ litre BA equivalent significantly increased the leaf nitrogen and chlorophyll content of Alstroemeria cut flowers. High Accel concentrations of 50, 75 and 100 mg/litre BA equivalent reduced significantly the leaf water content of Alstroemeria cut flowers. Accel at 75 and 100 mg/litre BA equivalent increased leaf dry weight of Alstroemeria cut flowers. Our results indicate that Accel at 25 mg/litre BA equivalent has the potential to be used as a commercial cut flower preservative solution for delaying flower senescence, prolonging the vase life and enhancing post harvest quality of Alstroemeria cut flowers","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"834 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73842411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The maar Nyos, situated at latitude 6°26’78”N and 10°17’76”E along the Cameroon Volcanic Line is well known for its stratification from bottom to top. It lies on a granitic topography at 1100 m above sea level. The granitic cliff exposed to the west of the lake rises 100m above the water level. The lake waters are held behind to the north by a natural pyroclastic dam on which water overflows creating semi giant potholes. The overflow forms a waterfall of about 30-40m. This dam is highly and densely fractured (13 fractures of 23-40m long). The breakdown of this dam can create floods that will drawn over 10.000 people in both Cameroon and Nigeria (according to McKIE, 2000). The lake contains 3 billions m3 of water. At the bottom, the concentration of carbon dioxide is 85m/10m3 of water. The dam remains a great potential danger to the population, aggravated by the high concentration of carbon dioxide in the lake emanating from the mantle which can lead to another gas disaster. The tectonic instability or ever a slight earth tremors can break the dam and cause floods downstream. A volcanic eruption might even worsen the situation. This paper presents the results of a recent research carried out on the lake after the onset of the first phase of the degassing project.
maar Nyos位于北纬6°26 ' 78 "和东经10°17 ' 76 "，沿着喀麦隆火山线，以其自下而上的分层而闻名。它位于海拔1100米的花岗岩地形上。暴露在湖西面的花岗岩悬崖高出水面100米。湖水被一个天然的火山碎屑坝挡在北面，湖水在上面溢出，形成了半巨大的坑洞。溢流形成约30-40米的瀑布。坝体断裂高度密集，有13条长23-40米的裂缝。大坝的崩溃可能会造成洪水，在喀麦隆和尼日利亚将吸引超过1万人(根据McKIE, 2000)。这个湖有30亿立方米的水。底部二氧化碳浓度为85m/10m3水。大坝对人们来说仍然是一个巨大的潜在危险，而从地幔中释放出来的高浓度二氧化碳会导致另一场天然气灾难。构造不稳定或轻微的地震都可能破坏大坝，导致下游洪水泛滥。火山爆发甚至可能使情况恶化。本文介绍了在第一期脱气工程开始后对该湖进行的最新研究结果。
{"title":"Risque d’inondation dans la vallee de nyos","authors":"M. Tchindjang, Ni Konfor","doi":"10.4314/AJST.V2I2.44671","DOIUrl":"https://doi.org/10.4314/AJST.V2I2.44671","url":null,"abstract":"The maar Nyos, situated at latitude 6°26’78”N and 10°17’76”E along the Cameroon Volcanic Line is well known for its stratification from bottom to top. It lies on a granitic topography at 1100 m above sea level. The granitic cliff exposed to the west of the lake rises 100m above the water level. The lake waters are held behind to the north by a natural pyroclastic dam on which water overflows creating semi giant potholes. The overflow forms a waterfall of about 30-40m. This dam is highly and densely fractured (13 fractures of 23-40m long). The breakdown of this dam can create floods that will drawn over 10.000 people in both Cameroon and Nigeria (according to McKIE, 2000). The lake contains 3 billions m3 of water. At the bottom, the concentration of carbon dioxide is 85m/10m3 of water. The dam remains a great potential danger to the population, aggravated by the high concentration of carbon dioxide in the lake emanating from the mantle which can lead to another gas disaster. The tectonic instability or ever a slight earth tremors can break the dam and cause floods downstream. A volcanic eruption might even worsen the situation. This paper presents the results of a recent research carried out on the lake after the onset of the first phase of the degassing project.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77455238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The insecticidal and antifeedant activity of extracts derived from different parts of the mangrove tree Rhizophora mucronata (Rhizophoraceae) Lam. is reported. The 70% ethanol extracts of leaves, bark, stem wood and pith were tested for toxicity against adults of the desert locust Schistocerca gregaria (Forskal), the 2nd instar larvae of Aedes aegypti (L.) and the 1st instar larvae of the brine shrimp Artemia salina (Leach). Antifeedant activity of the extracts was assessed through tests conducted on S. gregaria adults by the paper feeding protection bioassay. In tests carried out on A. aegypti mosquito larvae, bark and pith extracts showed high toxicity with 48 hour LC50’s of 157.4 ppm and 168.3 ppm respectively. Stem wood extracts had low activity with an LC50 of 1003.4 ppm while leaf extracts did not exhibit toxic effects at a concentration of 1000 ppm. A similar trend in activity was observed with antifeedant tests conducted on the desert locust S. gregaria and on toxicity tests carried out on A. salina larvae. The bulk of the active compounds are sequestered in the bark, pith and stem wood with the least being found in the leaves. The results indicate that R.mucronata is a potential source of botanical insecticides(s).
{"title":"Insecticidal activity of extracts derived from different parts of the mangrove tree rhizophora mucronata (rhizophoraceae) lam. Against three arthropods","authors":"J. Kabaru, L. Gichia","doi":"10.4314/AJST.V2I2.44668","DOIUrl":"https://doi.org/10.4314/AJST.V2I2.44668","url":null,"abstract":"The insecticidal and antifeedant activity of extracts derived from different parts of the mangrove tree Rhizophora mucronata (Rhizophoraceae) Lam. is reported. The 70% ethanol extracts of leaves, bark, stem wood and pith were tested for toxicity against adults of the desert locust Schistocerca gregaria (Forskal), the 2nd instar larvae of Aedes aegypti (L.) and the 1st instar larvae of the brine shrimp Artemia salina (Leach). Antifeedant activity of the extracts was assessed through tests conducted on S. gregaria adults by the paper feeding protection bioassay. In tests carried out on A. aegypti mosquito larvae, bark and pith extracts showed high toxicity with 48 hour LC50’s of 157.4 ppm and 168.3 ppm respectively. Stem wood extracts had low activity with an LC50 of 1003.4 ppm while leaf extracts did not exhibit toxic effects at a concentration of 1000 ppm. A similar trend in activity was observed with antifeedant tests conducted on the desert locust S. gregaria and on toxicity tests carried out on A. salina larvae. The bulk of the active compounds are sequestered in the bark, pith and stem wood with the least being found in the leaves. The results indicate that R.mucronata is a potential source of botanical insecticides(s).","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83626716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The seismotectonics of Zimbabwe is presented in this paper. Data used in the study are from instrumental records for the period 1910-1991 sourced from available seismological bulletins. Earthquake magnitudes are unified to surface-wave magnitude (Ms), facilitating easy evaluation of seismicity of the region. Seismicity is confined to regions with broad scale lineaments that trend in a north-easterly direction. Seismic hazard potential for Zimbabwe may be inferred from the total magnitude representing the seismic wave energy. Fault plane solutions and energy release during the period of study show that high seismic hazard potential lies along the Deka fault zone mid- Zambezi basin to the north and northwest of Zimbabwe, in the Save-Limpopo mobile belt to the south of Zimbabwe and along the Zimbabwe eastern highlands, bordering Mozambique.
{"title":"SEISMOTECTONICS OF ZIMBABWE","authors":"Jh Dumisani","doi":"10.4314/AJST.V1I4.44622","DOIUrl":"https://doi.org/10.4314/AJST.V1I4.44622","url":null,"abstract":"The seismotectonics of Zimbabwe is presented in this paper. Data used in the study are from instrumental records for the period 1910-1991 sourced from available seismological bulletins. Earthquake magnitudes are unified to surface-wave magnitude (Ms), facilitating easy evaluation of seismicity of the region. Seismicity is confined to regions with broad scale lineaments that trend in a north-easterly direction. Seismic hazard potential for Zimbabwe may be inferred from the total magnitude representing the seismic wave energy. Fault plane solutions and energy release during the period of study show that high seismic hazard potential lies along the Deka fault zone mid- Zambezi basin to the north and northwest of Zimbabwe, in the Save-Limpopo mobile belt to the south of Zimbabwe and along the Zimbabwe eastern highlands, bordering Mozambique.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91055649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pot and field experiments were conducted to compare the effects of dairy cow, goat and poultry manures on soil available levels of N and P and amaranths yield and root growth. The three amendments were applied on Oxisols at 100, 150 and 170 kg N/ha in a split plot design and replicated three times. Pot experiment lasted for one month whereas field experiment was conducted over three monthly crop cycles. Results of both experiments indicated that applications of the three manures significantly (P from the three manures revealed that for all the parameters evaluated the trend was; Poultry manure > goat manure > dairy cow manure. This was largely attributed to differences in total N, total P, C/N and C/P ratios of the amendments. Field experiment results revealed that responses were highest after the third crop harvest suggesting that mineralization of organic N and P increased with time. Based on fertilizer recommendations of N and P for Southern highlands of Tanzania and the highest rate used in this study (170 kg N/ha), applications of 5.8 tons/ha, 9.8 tons/ha and 13.4 tons/ha of poultry, goat and dairy cow manure will suffice the equirement of 40 kg N/ha and 20 kg P/ha recommended for most field crops.
通过盆栽和田间试验，比较了奶牛、山羊和家禽粪便对土壤速效氮磷水平、苋菜产量和根系生长的影响。3种改良剂分别以100、150和170 kg N/ hm2在Oxisols上施用，并重复施用3次。盆栽试验为1个月，田间试验为3个月。两种试验结果均表明，施用三种肥料显著(P)表明，对所有评估参数的趋势为;禽粪>山羊粪>奶牛粪。这在很大程度上是由于全氮、全磷、碳氮比和碳磷比的差异造成的。田间试验结果表明，在第三季收获后响应最高，表明有机氮和磷的矿化随时间而增加。根据坦桑尼亚南部高地氮肥和磷肥的建议用量以及本研究的最高用量(170公斤氮/公顷)，对大多数大田作物施用5.8吨/公顷、9.8吨/公顷和13.4吨/公顷的家禽、山羊和奶牛粪便将满足40公斤氮/公顷和20公斤磷/公顷的建议需要量。
{"title":"Comparative effectiveness of animal manures on soil chemical properties, yield and root growth of amaranthus (amaranthus cruentus l.)","authors":"A. Maerere, GG Kimbi, Dlm Nonga","doi":"10.4314/AJST.V1I4.44623","DOIUrl":"https://doi.org/10.4314/AJST.V1I4.44623","url":null,"abstract":"Pot and field experiments were conducted to compare the effects of dairy cow, goat and poultry manures on soil available levels of N and P and amaranths yield and root growth. The three amendments were applied on Oxisols at 100, 150 and 170 kg N/ha in a split plot design and replicated three times. Pot experiment lasted for one month whereas field experiment was conducted over three monthly crop cycles. Results of both experiments indicated that applications of the three manures significantly (P from the three manures revealed that for all the parameters evaluated the trend was; Poultry manure > goat manure > dairy cow manure. This was largely attributed to differences in total N, total P, C/N and C/P ratios of the amendments. Field experiment results revealed that responses were highest after the third crop harvest suggesting that mineralization of organic N and P increased with time. Based on fertilizer recommendations of N and P for Southern highlands of Tanzania and the highest rate used in this study (170 kg N/ha), applications of 5.8 tons/ha, 9.8 tons/ha and 13.4 tons/ha of poultry, goat and dairy cow manure will suffice the equirement of 40 kg N/ha and 20 kg P/ha recommended for most field crops.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79788055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A variable structure Automatic Generation Control (VSAGC) scheme is proposed in this paper for the control of a single area power system model dominated by steam powered electric generating plants. Unlike existing, VSAGC scheme where the selection of the control function is based on a trial and error procedure, the strategy proposed here relies on a systematic approach based on the unit vector control concept. Simulation results show the superiority of the proposed control scheme over the existing ones.
{"title":"Variable structure unit vector control of electric power generation","authors":"F. Okafor","doi":"10.4314/AJST.V1I4.44627","DOIUrl":"https://doi.org/10.4314/AJST.V1I4.44627","url":null,"abstract":"A variable structure Automatic Generation Control (VSAGC) scheme is proposed in this paper for the control of a single area power system model dominated by steam powered electric generating plants. Unlike existing, VSAGC scheme where the selection of the control function is based on a trial and error procedure, the strategy proposed here relies on a systematic approach based on the unit vector control concept. Simulation results show the superiority of the proposed control scheme over the existing ones.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75223478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Combustion phenomena have been found to be dependent on the turbulence of the air/gas and fuel in the cylinder. By enhancing turbulent mixing of fuel in the combustion chamber it is possible to improve combustion process. Based on the stochastic nature of turbulence of combustion processes as occurring in an IDI internal combustion engine, a model was developed based on these principles when compressed air was injected into the engine. The air injection was carried out in order to control the emission of NOx and soot simultaneously. In the present model, the mechanism of NOx formation is modeled using the thermal NOx principles while the soot emission is modeled using the global combustion model, which considered combustion as heat addition. Obtained results show close agreement with the experimental ones. The Zeldovich model used has been found model closely IDI engine processes also for the case of air injection as is case of a normal engine. This is due to the microscopic treatment of the mixing process, which involved over-simplification of HC combustion chemistry. It is shown that although there is no substantial temperature drop when compressed air was injected into the chamber, at microscopic scales, the mixing process that occur lead to local temperature drop. It is these local areas of temperature quenching that enhance the suppression of the formation of NOx. At high loads, however, particulate and HC are increased due to the enrichment of fuel in the local areas where the temperatures have substantially been reduced.
{"title":"Analysis of NO x reduction in diesel engines by air injection using stochastic","authors":"I. Mkilaha, G. John","doi":"10.4314/AJST.V1I4.44624","DOIUrl":"https://doi.org/10.4314/AJST.V1I4.44624","url":null,"abstract":"Combustion phenomena have been found to be dependent on the turbulence of the air/gas and fuel in the cylinder. By enhancing turbulent mixing of fuel in the combustion chamber it is possible to improve combustion process. Based on the stochastic nature of turbulence of combustion processes as occurring in an IDI internal combustion engine, a model was developed based on these principles when compressed air was injected into the engine. The air injection was carried out in order to control the emission of NOx and soot simultaneously. In the present model, the mechanism of NOx formation is modeled using the thermal NOx principles while the soot emission is modeled using the global combustion model, which considered combustion as heat addition. Obtained results show close agreement with the experimental ones. The Zeldovich model used has been found model closely IDI engine processes also for the case of air injection as is case of a normal engine. This is due to the microscopic treatment of the mixing process, which involved over-simplification of HC combustion chemistry. It is shown that although there is no substantial temperature drop when compressed air was injected into the chamber, at microscopic scales, the mixing process that occur lead to local temperature drop. It is these local areas of temperature quenching that enhance the suppression of the formation of NOx. At high loads, however, particulate and HC are increased due to the enrichment of fuel in the local areas where the temperatures have substantially been reduced.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89594187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Baluba east concentrator is part of the Roan Antelope Mining Corporation (RAMCO) which is a unit of the Binani Group of Companies. It treats an ore which is a mixture of sulphide and oxide copper minerals. In the flotation of mixed sulphide - oxide ores, the sulphide minerals are floated first, then followed by a sulphidisation step of the oxide minerals to effect their flotation. This test work was carried out because of a decrease in the grades and recoveries obtainable during the period of January 1998 up to around September 1998. This was so despite having an above average head grade of 1.91%Tcu. The optimum mesh of grind was found to be 65% passing 75 im using release analysis and the conclusions were drawn on the basis of flotation kinetics. The optimisation of reagents addition was done using a FACTORIAL DESIGN of experiments to improve the reliability of the result and Analysis of Variance(ANOVA) and the F-test were used to draw meaningful conclusions. Dosages of 120g/t collector (SIPX) and 100 g/t conditioner (NaHS) were obtained as the optimum reagent levels. The associated concentrate grade was 6.10%TCu (without a cleaning stage) at a recovery of 90.16%TCu. This adjustment in reagent consumption rates, if effected, would introduce a 10% reduction in collector consumption and a 50% reduction in conditioner consumption, which clearly indicates a significant reduction in the overall costs of reagents per tonne ore treated.
{"title":"Optimisation of the baluba east ore treatment","authors":"C. Chabuka, L. Witika","doi":"10.4314/AJST.V1I4.44621","DOIUrl":"https://doi.org/10.4314/AJST.V1I4.44621","url":null,"abstract":"The Baluba east concentrator is part of the Roan Antelope Mining Corporation (RAMCO) which is a unit of the Binani Group of Companies. It treats an ore which is a mixture of sulphide and oxide copper minerals. In the flotation of mixed sulphide - oxide ores, the sulphide minerals are floated first, then followed by a sulphidisation step of the oxide minerals to effect their flotation. This test work was carried out because of a decrease in the grades and recoveries obtainable during the period of January 1998 up to around September 1998. This was so despite having an above average head grade of 1.91%Tcu. The optimum mesh of grind was found to be 65% passing 75 im using release analysis and the conclusions were drawn on the basis of flotation kinetics. The optimisation of reagents addition was done using a FACTORIAL DESIGN of experiments to improve the reliability of the result and Analysis of Variance(ANOVA) and the F-test were used to draw meaningful conclusions. Dosages of 120g/t collector (SIPX) and 100 g/t conditioner (NaHS) were obtained as the optimum reagent levels. The associated concentrate grade was 6.10%TCu (without a cleaning stage) at a recovery of 90.16%TCu. This adjustment in reagent consumption rates, if effected, would introduce a 10% reduction in collector consumption and a 50% reduction in conditioner consumption, which clearly indicates a significant reduction in the overall costs of reagents per tonne ore treated.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83252972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Adamawa dome in Central Cameroon represents a post-Cretaceous uplifted region, paralled to a Precambrian Foumban Shear Zone, and characterised by Tertiary-Recent volcanic centres of the Cameroon Volcanic Line, and a long negative Bouguer anomaly similar in shape and amplitude to those of other African domes. Using the Admittance Technique of gravity data, the present study aims at computing the Isostatic Compensation Mechanism of the region of the Adamawa dome. The results show that the dome is overcompensated and fits models involving density contrasts beneath the elastic plate and the consequent upwarping of the plate above low density material at depths. A comparison of the Adamawa admittance to the East African and Ethiopian plateau shows that a dynamic compensation mechanism may not be ruled out entirely for the Adamawa dome. Le dome de l’Adamaoua, au centre du Cameroun, est caracterise par des volcans datant du Tertiaire au Recent et appartenant a la ligne volcanique du Cameroun. Ce dome est parallele a une zone cisaillee precambrienne et a une longue anomalie de Bouguer, il ressemble aux autres domes africains par sa forme et son etendue. Dans cette etude, l’admittance ou la fonction de reponse isostatique du dome de l’Adamaoua determinee a partir des donnees gravimetriques montre que le dome est exagerement compense et est comparable aux modeles qui presentent des contrastes de densite entre la plaque elastique et l’escarpement subsequent de la plaque situee au-dessus des couches moins denses des profondeurs. En comparant l’admittance du dome de l’Adamaoua avec des plateaux de l’Afrique de l’Est et d’Ethiopie, on constate qu’un mecanisme de compensation dynamique est aussi une hypothese envisageable dans ce contexte.
{"title":"Determination of the isostatic compensation mechanism of the region of the Adamawa dome, West Central Africa using the admittance technique of gravity data.","authors":"J. M. Nnange, Y. Djomani, J. Fairhead, C. Ebinger","doi":"10.4314/AJST.V1I4.44626","DOIUrl":"https://doi.org/10.4314/AJST.V1I4.44626","url":null,"abstract":"The Adamawa dome in Central Cameroon represents a post-Cretaceous uplifted region, paralled to a Precambrian Foumban Shear Zone, and characterised by Tertiary-Recent volcanic centres of the Cameroon Volcanic Line, and a long negative Bouguer anomaly similar in shape and amplitude to those of other African domes. Using the Admittance Technique of gravity data, the present study aims at computing the Isostatic Compensation Mechanism of the region of the Adamawa dome. The results show that the dome is overcompensated and fits models involving density contrasts beneath the elastic plate and the consequent upwarping of the plate above low density material at depths. A comparison of the Adamawa admittance to the East African and Ethiopian plateau shows that a dynamic compensation mechanism may not be ruled out entirely for the Adamawa dome. Le dome de l’Adamaoua, au centre du Cameroun, est caracterise par des volcans datant du Tertiaire au Recent et appartenant a la ligne volcanique du Cameroun. Ce dome est parallele a une zone cisaillee precambrienne et a une longue anomalie de Bouguer, il ressemble aux autres domes africains par sa forme et son etendue. Dans cette etude, l’admittance ou la fonction de reponse isostatique du dome de l’Adamaoua determinee a partir des donnees gravimetriques montre que le dome est exagerement compense et est comparable aux modeles qui presentent des contrastes de densite entre la plaque elastique et l’escarpement subsequent de la plaque situee au-dessus des couches moins denses des profondeurs. En comparant l’admittance du dome de l’Adamaoua avec des plateaux de l’Afrique de l’Est et d’Ethiopie, on constate qu’un mecanisme de compensation dynamique est aussi une hypothese envisageable dans ce contexte.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83794369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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