Shishay Amare Gebremeskel, Neelanchali Asija, H. Chouhan, N. Bhatnagar
As a major challenge, development of light-weight fibre reinforced polymer (FRP) composite body armour, characterization of candidate matrix polymers at high strain rate impact is the focus in this research. Polypropylene (PP) and the nano-composites with 1-5% by weight of NC (nanoclay) platelets are the candidates considered. In the characterization phase, high strain rate impact and quasi-static loading tests were performed to figure out the limiting (failure) responses. Comparison between the material systems is, subsequently, made to nominate one matrix configuration. Enhancements of mechanical properties with increase in weight percentage of the nanoparticles are observed at both quasi-static and dynamic loadings. Observations of dispersed imposed failure modes, development of novel model for failure modulus and evaluation of peak strength values are also attempted. Keywords : Nano-composite, Impact behaviour, Analytical modelling, Polypropylene, Failure mode.
{"title":"Polypropylene nano-composites at high strain rate impacts: Characterization, failure modes, and modeling","authors":"Shishay Amare Gebremeskel, Neelanchali Asija, H. Chouhan, N. Bhatnagar","doi":"10.4314/MEJS.V10I1.3","DOIUrl":"https://doi.org/10.4314/MEJS.V10I1.3","url":null,"abstract":"As a major challenge, development of light-weight fibre reinforced polymer (FRP) composite body armour, characterization of candidate matrix polymers at high strain rate impact is the focus in this research. Polypropylene (PP) and the nano-composites with 1-5% by weight of NC (nanoclay) platelets are the candidates considered. In the characterization phase, high strain rate impact and quasi-static loading tests were performed to figure out the limiting (failure) responses. Comparison between the material systems is, subsequently, made to nominate one matrix configuration. Enhancements of mechanical properties with increase in weight percentage of the nanoparticles are observed at both quasi-static and dynamic loadings. Observations of dispersed imposed failure modes, development of novel model for failure modulus and evaluation of peak strength values are also attempted. Keywords : Nano-composite, Impact behaviour, Analytical modelling, Polypropylene, Failure mode.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"10 1","pages":"28-50"},"PeriodicalIF":0.3,"publicationDate":"2018-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/MEJS.V10I1.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46304737","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 use of a circuit simulator is more and more crucial in designing electrical and electronic gadgets. This technique makes it possible to obtain results when the hardware is unavailable or very costly. Simulations are widely used in the industry hence it is necessary to use it astutely. Authors tried to study an important concept about “Squaring a Signal” and further it is extended to design and simulation of phase meter. Squaring a sinusoidal lead doubling its frequency and adding the dc component. In this study squaring sine wave with frequency of 5KHz gives a negative cosine wave with frequency 10KHz along with a dc term of 2V. TINA software is used for this study. TINA software has ability to perform DC analysis, AC analysis and transient analysis. Transient analysis calculates the circuit response to various input waveforms. Results are analyzed using transient analysis for sinusoidal input. Keywords : TINA, Simulation, Multipliers, Virtual instruments, Transient analysis, Phase.
电路模拟器的使用在设计电气和电子产品时越来越重要。这种技术使得在硬件不可用或非常昂贵时可以获得结果。模拟在工业中被广泛使用，因此有必要巧妙地使用它。作者试图研究“Squaring a Signal”的一个重要概念，并将其扩展到相位计的设计和仿真中。对正弦引线进行平方，使其频率加倍，并添加直流分量。在本研究中，将频率为5KHz的正弦波平方，得到频率为10KHz的负余弦波，直流项为2V。TINA软件用于本研究。TINA软件具有进行直流分析、交流分析和瞬态分析的能力。瞬态分析计算电路对各种输入波形的响应。使用正弦输入的瞬态分析来分析结果。关键词：TINA，仿真，乘法器，虚拟仪器，瞬态分析，相位。
{"title":"Simulation of Phase Meter using TINA Software","authors":"A. J. Chaudhari, R. Waghulade","doi":"10.4314/mejs.v10i1.4","DOIUrl":"https://doi.org/10.4314/mejs.v10i1.4","url":null,"abstract":"The use of a circuit simulator is more and more crucial in designing electrical and electronic gadgets. This technique makes it possible to obtain results when the hardware is unavailable or very costly. Simulations are widely used in the industry hence it is necessary to use it astutely. Authors tried to study an important concept about “Squaring a Signal” and further it is extended to design and simulation of phase meter. Squaring a sinusoidal lead doubling its frequency and adding the dc component. In this study squaring sine wave with frequency of 5KHz gives a negative cosine wave with frequency 10KHz along with a dc term of 2V. TINA software is used for this study. TINA software has ability to perform DC analysis, AC analysis and transient analysis. Transient analysis calculates the circuit response to various input waveforms. Results are analyzed using transient analysis for sinusoidal input. Keywords : TINA, Simulation, Multipliers, Virtual instruments, Transient analysis, Phase.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"10 1","pages":"51-58"},"PeriodicalIF":0.3,"publicationDate":"2018-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/mejs.v10i1.4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42427683","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}
Latent heat storage and efficient heat transport technology helps to utilize the intermittent solar energy for continuous and near isothermal applications. However, many latent heat storages face challenges of storage charging, heat retaining, and discharging the stored heat. This paper tries to address the challenges of heat transportation and storage charging-discharging issues. The heat transportation from the receiver over some distance, from outside to the kitchen, is carried out with a stainless pipeline and water as heat transfer fluids. However, the charging-discharging process is carried by conduction method with the help of fins. In addition, the stored heat is retained for about one-two days by using aerogel insulation. The latent heat is stored in a phase change material (PCM), nitrate salt (mixture of 60% NaNO 3 and 40% KNO 3 ), which melts at 222oC and has 109 J/g specific heat of fusion. The storage has the capacity of storing up to 250oC heat and supply this heat isothermally during baking in the liquid-solid phase transition. However, the sensible heat stored in the solid and liquid form of the PCM is used to perform additional applications that do not require uniform heat which includes bread baking, kita (large pancake) baking and water boiling. The low thermal conductivity of PCM is enhanced by using extended aluminum fins that are attached to the baking plate and extruded inward to the storage. In this paper, two-phase loop thermosyphon of steam is used to manage the long distance heat transportation required between the receiver (outside) and the storage (inside a house). The steam in the thermosyphon flow has restricted to a maximum working temperature of 250oC. Steam is selected for its highest heat capacity, availability and stable nature. It carries heat from the collector focus point and condenses in a coiled pipe imbedded in aluminum plate placed on top of the storage. Many fins are solidly attached to this plate to conduct the heat down to the PCM inside the storage during charging. This design configuration avoids pressure development inside the PCM storage and the charging-discharging temperature is recorded in three zones (top, middle and bottom) of the storage. The experimental and numerical results show that the heat transportation, retention and charging-discharging methods are effective. Keywords : Solar energy, PCM storage, Latent heat storage, Two-phase thermosyphon.
{"title":"Steam-based Charging-Discharging of a PCM Heat Storage","authors":"A. Tesfay, M. Kahsay, O. Nydal","doi":"10.4314/mejs.v10i1.2","DOIUrl":"https://doi.org/10.4314/mejs.v10i1.2","url":null,"abstract":"Latent heat storage and efficient heat transport technology helps to utilize the intermittent solar energy for continuous and near isothermal applications. However, many latent heat storages face challenges of storage charging, heat retaining, and discharging the stored heat. This paper tries to address the challenges of heat transportation and storage charging-discharging issues. The heat transportation from the receiver over some distance, from outside to the kitchen, is carried out with a stainless pipeline and water as heat transfer fluids. However, the charging-discharging process is carried by conduction method with the help of fins. In addition, the stored heat is retained for about one-two days by using aerogel insulation. The latent heat is stored in a phase change material (PCM), nitrate salt (mixture of 60% NaNO 3 and 40% KNO 3 ), which melts at 222oC and has 109 J/g specific heat of fusion. The storage has the capacity of storing up to 250oC heat and supply this heat isothermally during baking in the liquid-solid phase transition. However, the sensible heat stored in the solid and liquid form of the PCM is used to perform additional applications that do not require uniform heat which includes bread baking, kita (large pancake) baking and water boiling. The low thermal conductivity of PCM is enhanced by using extended aluminum fins that are attached to the baking plate and extruded inward to the storage. In this paper, two-phase loop thermosyphon of steam is used to manage the long distance heat transportation required between the receiver (outside) and the storage (inside a house). The steam in the thermosyphon flow has restricted to a maximum working temperature of 250oC. Steam is selected for its highest heat capacity, availability and stable nature. It carries heat from the collector focus point and condenses in a coiled pipe imbedded in aluminum plate placed on top of the storage. Many fins are solidly attached to this plate to conduct the heat down to the PCM inside the storage during charging. This design configuration avoids pressure development inside the PCM storage and the charging-discharging temperature is recorded in three zones (top, middle and bottom) of the storage. The experimental and numerical results show that the heat transportation, retention and charging-discharging methods are effective. Keywords : Solar energy, PCM storage, Latent heat storage, Two-phase thermosyphon.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"10 1","pages":"15-27"},"PeriodicalIF":0.3,"publicationDate":"2018-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/mejs.v10i1.2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45477771","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}
Effects of Indole-3-Acid (IAA) on Citrullus lanatus plant height, leaf number, branching and flower production were studied in order to evaluate the optimum concentrations required for growth and development. Foliar application using five different concentrations [1, 5, 10, 20 and 0 ppm IAA] was conducted twice at two weeks interval. The results suggest that as IAA concentration increases, plant height decreases with an optimum concentration of 5 ppm IAA. Mean plant height was also significantly different. More so, optimum concentration for leaf production and branching varied with varietal difference. Results obtained for number of branching suggest that 1 ppm IAA is optimum for variety A and 10 ppm is optimum for varieties B, C and D. Although flower production was poor during the study, high flower production is recorded for plants in 20 ppm IAA at 6 weeks after planting for all the varieties. This work establishes the inducing effects of different IAA concentration, which may be exploited for the commercial production of C. lanatus. Keywords : Watermelon (Citrullus lanatus), Indole-3-Acetic acid, Growth parameters, Leaf production, Plant Physiology.
{"title":"Effects of Indole-3-Acetic Acid on the Growth Parameters of Citrullus lanatus (Thunberg) Matsum and Nakai","authors":"M. Ogwu","doi":"10.4314/mejs.v10i1.8","DOIUrl":"https://doi.org/10.4314/mejs.v10i1.8","url":null,"abstract":"Effects of Indole-3-Acid (IAA) on Citrullus lanatus plant height, leaf number, branching and flower production were studied in order to evaluate the optimum concentrations required for growth and development. Foliar application using five different concentrations [1, 5, 10, 20 and 0 ppm IAA] was conducted twice at two weeks interval. The results suggest that as IAA concentration increases, plant height decreases with an optimum concentration of 5 ppm IAA. Mean plant height was also significantly different. More so, optimum concentration for leaf production and branching varied with varietal difference. Results obtained for number of branching suggest that 1 ppm IAA is optimum for variety A and 10 ppm is optimum for varieties B, C and D. Although flower production was poor during the study, high flower production is recorded for plants in 20 ppm IAA at 6 weeks after planting for all the varieties. This work establishes the inducing effects of different IAA concentration, which may be exploited for the commercial production of C. lanatus. Keywords : Watermelon (Citrullus lanatus), Indole-3-Acetic acid, Growth parameters, Leaf production, Plant Physiology.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"10 1","pages":"109-125"},"PeriodicalIF":0.3,"publicationDate":"2018-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/mejs.v10i1.8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42382181","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}
Sorghum (Sorghum bicolor (L.) Moench) is an important cereal crop and stable food for the semi-arid small scale farming communities in the third world. Even though, it is highly adapted to different agro-ecological conditions, its yield is constrained by different factors including declining soil fertility and improper utilization of fertilizer. Results of the research conducted in Shire-Mytsebri Agricultural Research Center at Sheraro sub-site during the main cropping season of 2016 are presented in the paper. The aim was to investigate the effect of NPK; and blended fertilizer on nitrogen, phosphorus, and potassium uptake; and nutrient use efficiency of selected sorghum varieties. The treatments are comprised of factorial combination of ten levels of fertilizers including the recently recommended [N, P, Blanket recommendation (NP), NPK, NPS, NPKS, NPKSZn, NPKSZnB, NPKSZnB (after Agricultural Transformation Agency, ATA) and Control (0)]. Two sorghum varieties (Melkam and Dekeba) were tested in a Factorial Randomized Complete Block Design with three replications. The data were computed using four agronomic indices, which are commonly used to describe nutrient (N, P and K) uptake and use efficiency. The results indicate that there is a significant interaction effect of fertilizer treatments and sorghum varieties on majority of the parameters studied. Application of NPKSZn blended fertilizer significantly enhanced nutrient uptake and use efficiency. The highest total N (78.70 kg ha-1), P (51.19 kgha-1) and K (74 kg ha-1) uptake and use efficiency in Melkam variety treated by fertilizer contained NPKSZn brought higher yield (5541 kg ha-1). Increasing uptake of the major nutrient elements ensured ample nutrient availability for normal growth and high yield of sorghum. Thus, application of macronutrients in combination with micronutrients increased sorghum yield and concomitantly improved N, P and K uptake, and nutrient use efficiency for the sorghum varieties used in the study. Therefore, it is recommended that in the study area and other similar areas blended fertilizer 41N-46P-13.7K-9.25S-1.72Zn kg ha-1 be used to achieve higher yields.
高粱（Sorghum bicolor（L.）Moench）是第三世界半干旱小规模农业社区的重要谷物作物和稳定食物。尽管它高度适应不同的农业生态条件，但其产量受到不同因素的制约，包括土壤肥力下降和肥料利用不当。本文介绍了Shire Mytsebri农业研究中心Sheraro分中心在2016年主要种植季节进行的研究结果。目的是研究NPK的作用；以及混合肥料对氮、磷和钾吸收的影响；以及所选高粱品种的养分利用效率。处理由十个水平的肥料的因子组合组成，包括最近推荐的[N，P，Blanket推荐（NP），NPK，NPS，NPKS，NPKSZn，NPKSZnB，NPKSZnB（农业转型机构后，ATA）和对照（0）]。两个高粱品种（Melkam和Dekeba）在因子随机完全块设计中进行了三次重复试验。数据是使用四个农艺指标计算的，这四个指标通常用于描述养分（N、P和K）的吸收和利用效率。结果表明，肥料处理和高粱品种对所研究的大多数参数都有显著的交互作用。施用NPKSZn复合肥可显著提高养分吸收和利用效率。施用含NPKSZn的肥料处理后，麦甘品种的总氮（78.70 kg ha-1）、磷（51.19 kg ha-）和钾（74 kg ha-。对主要营养元素的吸收增加确保了高粱正常生长和高产所需的充足营养。因此，大量营养素与微量营养素的结合应用提高了高粱产量，同时提高了研究中使用的高粱品种的氮、磷、钾吸收和营养利用效率。因此，建议在研究区和其他类似地区使用混合肥料41N-46P-13.7K-9.25S-1.7Zn kg ha-1以获得更高的产量。
{"title":"Effect of NPK and Blended Fertilizer Application on Nutrient Uptake and Use Efficiency of Selected Sorghum (Sorghum bicolor (L.) Moench) Varieties Under Rain-fed Condition in Sheraro District, Northern Ethiopia","authors":"Redai Weldegebriel, T. Araya, Yemane G. Egziabher","doi":"10.4314/MEJS.V10I1.10","DOIUrl":"https://doi.org/10.4314/MEJS.V10I1.10","url":null,"abstract":"Sorghum (Sorghum bicolor (L.) Moench) is an important cereal crop and stable food for the semi-arid small scale farming communities in the third world. Even though, it is highly adapted to different agro-ecological conditions, its yield is constrained by different factors including declining soil fertility and improper utilization of fertilizer. Results of the research conducted in Shire-Mytsebri Agricultural Research Center at Sheraro sub-site during the main cropping season of 2016 are presented in the paper. The aim was to investigate the effect of NPK; and blended fertilizer on nitrogen, phosphorus, and potassium uptake; and nutrient use efficiency of selected sorghum varieties. The treatments are comprised of factorial combination of ten levels of fertilizers including the recently recommended [N, P, Blanket recommendation (NP), NPK, NPS, NPKS, NPKSZn, NPKSZnB, NPKSZnB (after Agricultural Transformation Agency, ATA) and Control (0)]. Two sorghum varieties (Melkam and Dekeba) were tested in a Factorial Randomized Complete Block Design with three replications. The data were computed using four agronomic indices, which are commonly used to describe nutrient (N, P and K) uptake and use efficiency. The results indicate that there is a significant interaction effect of fertilizer treatments and sorghum varieties on majority of the parameters studied. Application of NPKSZn blended fertilizer significantly enhanced nutrient uptake and use efficiency. The highest total N (78.70 kg ha-1), P (51.19 kgha-1) and K (74 kg ha-1) uptake and use efficiency in Melkam variety treated by fertilizer contained NPKSZn brought higher yield (5541 kg ha-1). Increasing uptake of the major nutrient elements ensured ample nutrient availability for normal growth and high yield of sorghum. Thus, application of macronutrients in combination with micronutrients increased sorghum yield and concomitantly improved N, P and K uptake, and nutrient use efficiency for the sorghum varieties used in the study. Therefore, it is recommended that in the study area and other similar areas blended fertilizer 41N-46P-13.7K-9.25S-1.72Zn kg ha-1 be used to achieve higher yields.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"10 1","pages":"140-156"},"PeriodicalIF":0.3,"publicationDate":"2018-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/MEJS.V10I1.10","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44194941","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}
Globally well-known ancient rock-hewn churches are present in Ethiopia in general and particularly in the central and eastern parts of Tigray regional state. They are important sites of heritage and tourism. Most of them are facing destabilization problem in different degree due to natural and anthropogenic factors. Among the affected, two churches hewn into sandstone located near Abreha-Atsibaha and Wukro (Kirkos/Cherkos church) in Tigray region were chosen for detailed study in terms of geological and engineering geological condition of the rocks in to which they are hewn. Both of them are affected by weathering and seepage. Both are carved into Mesozoic Adigrat sandstone that occupy higher elevations in topography, red in color and with iron and silica-rich alternating bands. Petrographic data suggest that the rock is dominated by quartz followed by feldspars; opaque and heavy minerals; pore spaces and carbonate/iron/silica cement. The rock is characterized by low to medium unconfined compressive strength. The alternating bands with varying mineralogical composition differ in mechanical properties and are responding differently to weathering and erosion. This is resulting in the development of minor spalling, pitting etc in the pillars, walls and roofs of the churches. Keeping the geological condition in view remedial measures are to be planned to minimize deterioration with time. Keywords : Geological, Geomechanical, Rock hewn-Church, Abraha-Atsibaha, Tigray, Ethiopia.
{"title":"Geological and Geomechanical Properties of Abraha-Atsibha and Wukro rock-hewn churches and its surroundings, Tigray Region, Northern Ethiopia","authors":"A. Abay, G. Mebrahtu, B. Konka","doi":"10.4314/MEJS.V9I2.4","DOIUrl":"https://doi.org/10.4314/MEJS.V9I2.4","url":null,"abstract":"Globally well-known ancient rock-hewn churches are present in Ethiopia in general and particularly in the central and eastern parts of Tigray regional state. They are important sites of heritage and tourism. Most of them are facing destabilization problem in different degree due to natural and anthropogenic factors. Among the affected, two churches hewn into sandstone located near Abreha-Atsibaha and Wukro (Kirkos/Cherkos church) in Tigray region were chosen for detailed study in terms of geological and engineering geological condition of the rocks in to which they are hewn. Both of them are affected by weathering and seepage. Both are carved into Mesozoic Adigrat sandstone that occupy higher elevations in topography, red in color and with iron and silica-rich alternating bands. Petrographic data suggest that the rock is dominated by quartz followed by feldspars; opaque and heavy minerals; pore spaces and carbonate/iron/silica cement. The rock is characterized by low to medium unconfined compressive strength. The alternating bands with varying mineralogical composition differ in mechanical properties and are responding differently to weathering and erosion. This is resulting in the development of minor spalling, pitting etc in the pillars, walls and roofs of the churches. Keeping the geological condition in view remedial measures are to be planned to minimize deterioration with time. Keywords : Geological, Geomechanical, Rock hewn-Church, Abraha-Atsibaha, Tigray, Ethiopia.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"9 1","pages":"182-199"},"PeriodicalIF":0.3,"publicationDate":"2017-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/MEJS.V9I2.4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47122470","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}
This paper aimed at evaluating the potential of the different soil attributes for plantation of selected forest trees ( Faidherbia albida, Eucalyptus camaldulensis and Balanitus aegiptica ) dominantly grown in the northern highlands of Ethiopia. The study was conducted at Korir watershed, northern Ethiopia. The method used to evaluate the land suitability was based on the FAO approach for land evaluation for forestry. The results of the evaluation revealed that suitability classes of these trees range from highly suitable (S1) to permanently not suitable (N). Eucalyptus camaldulensis was highly suitable on the relatively gentle valley bottom and foot slope (6% of the area) having greater soil depth while unsuitable in majority (about 58%) of the area. Both Faidherbia albida and Balanitus aegyptiaca were suitable in more than 85% of the study area. The major limiting factors were the steep slope and shallow soil depth in major part of the area. Hence, evaluating the land potential for individual species and assigning these species based on their land requirements should be done before plantation so as to increase the trees' survival rate. Keywords : Faidherbia albida , Eucalyptus camaldulensis, Balanitus aegiptica , Suitability, Ethiopia
{"title":"Evaluation of Land Suitability for Selected Tree Species in the Mesozoic Highlands of Ethiopia","authors":"K. Teka, Yemane Welday","doi":"10.4314/MEJS.V9I2.6","DOIUrl":"https://doi.org/10.4314/MEJS.V9I2.6","url":null,"abstract":"This paper aimed at evaluating the potential of the different soil attributes for plantation of selected forest trees ( Faidherbia albida, Eucalyptus camaldulensis and Balanitus aegiptica ) dominantly grown in the northern highlands of Ethiopia. The study was conducted at Korir watershed, northern Ethiopia. The method used to evaluate the land suitability was based on the FAO approach for land evaluation for forestry. The results of the evaluation revealed that suitability classes of these trees range from highly suitable (S1) to permanently not suitable (N). Eucalyptus camaldulensis was highly suitable on the relatively gentle valley bottom and foot slope (6% of the area) having greater soil depth while unsuitable in majority (about 58%) of the area. Both Faidherbia albida and Balanitus aegyptiaca were suitable in more than 85% of the study area. The major limiting factors were the steep slope and shallow soil depth in major part of the area. Hence, evaluating the land potential for individual species and assigning these species based on their land requirements should be done before plantation so as to increase the trees' survival rate. Keywords : Faidherbia albida , Eucalyptus camaldulensis, Balanitus aegiptica , Suitability, Ethiopia","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"9 1","pages":"215-231"},"PeriodicalIF":0.3,"publicationDate":"2017-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/MEJS.V9I2.6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41406524","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}
Low soil fertility is one of the major factors limiting the yield of barley in Kaffa Zone, south-western Ethiopia. The problem is more severe in the Zone due to soil erosion and nutrient leaching caused by heavy and continuous rainfall. Thus, field experiment was conducted to assess the effect of combined organic and mineral nitrogen (N) and phosphorus (P) on selected soil physico-chemical properties and on grain yield of food barley in Ghimbo and Adiyo districts, south-western Ethiopia. Fourteen treatments comprising two organic fertilizer rates, i.e. 2.5 and 5 t ha −1 of Farm Yard Manure (FYM) and Vermicomost (VC) combined with three levels of mineral NP (25, 50 and 75% of recommended rates of NP), 100% recommended rate of inorganic NP (23 kg N ha -1 and 46 kg P 2 O 5 ha -1 ) and no fertilizer application (control) in randomized complete block design on clay soil in Ghimbo and clay loam soil in Adiyo with three replications. Results indicated that the application of FYM in combination with different levels of recommended rates of inorganic N and P significantly improved most of the soil physico-chemical properties and significantly increased the grain yield of food barley over the application of 100% mineral NP alone and the control. The application of 5 t FYM ha −1 in combination with 75% recommended rates of inorganic N and P (17.25 kg N ha −1 and 34.5 kg P 2 O 5 ha −1 ) was found to be superior and increased soil organic carbon content by 36 and 44.6%, available P by 70.5 and 78.2%, available K by 42.5 and 26.3%, and increased yield of barley by 76.8 and 83.5% in Adiyo and Ghimbo, respectively, over the application of 100% recommended rate of inorganic N and P only. Therefore, it can be concluded and recommended that the application of 5 t FYM ha −1 in combination with 75% of the recommended rates of inorganic N and P (17.25 kg N ha −1 and 34.5 kg P 2 O 5 ha −1 ) can improve soil fertility and can increase yield of food barley in the study area. Keywords: Farmyard manure, Nitrogen, Phosphorous, Vermicompost, Ethiopia.
土壤肥力低是限制埃塞俄比亚西南部Kaffa地区大麦产量的主要因素之一。由于强降雨和持续降雨造成的土壤侵蚀和养分流失，该地区的问题更加严重。因此，在埃塞俄比亚西南部的Ghimbo和Adiyo地区进行了田间试验，以评估有机和矿物氮（N）和磷（P）对选定土壤物理化学性质和粮食大麦产量的影响。14个处理包括两种有机肥料施用率，即2.5和5 t ha−1的农田肥料（FYM）和Vermicmost（VC）与三种水平的矿物NP（NP推荐施用率的25%、50%和75%），在Ghimbo粘土和Adiyo粘壤土上进行的随机完全块区设计中，无机NP（23 kg N ha-1和46 kg P 2 O 5 ha-1）和不施肥（对照）的推荐率为100%，三次重复。结果表明，与单独施用100%无机氮磷和对照相比，FYM与不同无机氮磷推荐施用水平的组合显著改善了大部分土壤理化性质，并显著提高了粮食大麦的产量。施用5 t FYM ha−1与75%的无机氮和磷推荐量（17.25 kg N ha−1和34.5 kg P 2 O 5 ha−1）效果较好，分别使阿迪约和吉姆博的土壤有机碳含量增加了36和44.6%，有效磷增加了70.5和78.2%，有效钾增加了42.5和26.3%，大麦产量增加了76.8和83.5%，超过仅施用100%推荐速率的无机氮和磷。因此，可以得出结论并建议，5 t FYM ha−1与75%的无机氮和磷推荐施用量（17.25 kg N ha−1和34.5 kg P 2 O 5 ha−1）相结合，可以提高研究区的土壤肥力，并可以提高食用大麦的产量。关键词：农家肥，氮，磷，蚯蚓粪，埃塞俄比亚。
{"title":"Effect of Combined Application of Organic and Mineral Nitrogen and Phosphorus Fertilizer on Soil Physico-chemical Properties and Grain Yield of Food Barley (Hordeum vulgare L.) in Kaffa Zone, South-western Ethiopia","authors":"T. Tana, M. Woldesenbet","doi":"10.4314/mejs.v9i2.8","DOIUrl":"https://doi.org/10.4314/mejs.v9i2.8","url":null,"abstract":"Low soil fertility is one of the major factors limiting the yield of barley in Kaffa Zone, south-western Ethiopia. The problem is more severe in the Zone due to soil erosion and nutrient leaching caused by heavy and continuous rainfall. Thus, field experiment was conducted to assess the effect of combined organic and mineral nitrogen (N) and phosphorus (P) on selected soil physico-chemical properties and on grain yield of food barley in Ghimbo and Adiyo districts, south-western Ethiopia. Fourteen treatments comprising two organic fertilizer rates, i.e. 2.5 and 5 t ha −1 of Farm Yard Manure (FYM) and Vermicomost (VC) combined with three levels of mineral NP (25, 50 and 75% of recommended rates of NP), 100% recommended rate of inorganic NP (23 kg N ha -1 and 46 kg P 2 O 5 ha -1 ) and no fertilizer application (control) in randomized complete block design on clay soil in Ghimbo and clay loam soil in Adiyo with three replications. Results indicated that the application of FYM in combination with different levels of recommended rates of inorganic N and P significantly improved most of the soil physico-chemical properties and significantly increased the grain yield of food barley over the application of 100% mineral NP alone and the control. The application of 5 t FYM ha −1 in combination with 75% recommended rates of inorganic N and P (17.25 kg N ha −1 and 34.5 kg P 2 O 5 ha −1 ) was found to be superior and increased soil organic carbon content by 36 and 44.6%, available P by 70.5 and 78.2%, available K by 42.5 and 26.3%, and increased yield of barley by 76.8 and 83.5% in Adiyo and Ghimbo, respectively, over the application of 100% recommended rate of inorganic N and P only. Therefore, it can be concluded and recommended that the application of 5 t FYM ha −1 in combination with 75% of the recommended rates of inorganic N and P (17.25 kg N ha −1 and 34.5 kg P 2 O 5 ha −1 ) can improve soil fertility and can increase yield of food barley in the study area. Keywords: Farmyard manure, Nitrogen, Phosphorous, Vermicompost, Ethiopia.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"9 1","pages":"242-261"},"PeriodicalIF":0.3,"publicationDate":"2017-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/mejs.v9i2.8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48037916","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}
This paper is aimed to investigate diurnal, monthly and seasonal variation of ionospheric total electronic content (TEC) obtained from two GPS satellites IGS and COD and to inspect mean VTEC Correlation between the two satellites by the year of 2008. TEC is defined by the integral of electron density in a 1 m 2 column along the signal transmission path. It is an important parameter to monitor possible space weather impacts. The processed and archived data taken from IGS and COD satellites has been imported in to a MATLAB code which gave us the results of the value of VTEC. Results of the two satellites revealed that, Out of the selected equinox and solstice day’s maximum value of TEC is recorded on March 20/2008 over North and South west equator due to the maximum solar radiation reaching to the ionosphere of the Earth. On the contrary, the Minimum peak ionospheric TEC value is recorded on June 21/2008 over south Asia particularly Srilanka and Bangladesh due to emission of low solar radiation. As regards to monthly variations of ionospheric TEC, results of IGS and COD satellites show that highest mean TEC value is recorded on March and July recorded the least peak TEC value. Results regarding to seasonal variation also revealed that E-Season recorded maximum TEC value and least TEC value is recorded on J-Season. The observations of the two satellites also show that the mean TEC value presents stronger solar activity sensitivity at lower-latitude bands than the middle and high latitudes. In general, there was a very high correlation between Mean TEC value recorded by IGS and COD satellites by the year of 2008 in all low, middle and high latitudes. Keywords : IGS and COD satellites, GPS, Ionosphere, Low, middle and high-latitudes, TEC.
{"title":"Global Variations of Ionospheric Total Electron Content (TEC) Derived from GPS Global Ionospheric Maps","authors":"Hintsa Gebreselasse, G. Abraha","doi":"10.4314/mejs.v9i2.2","DOIUrl":"https://doi.org/10.4314/mejs.v9i2.2","url":null,"abstract":"This paper is aimed to investigate diurnal, monthly and seasonal variation of ionospheric total electronic content (TEC) obtained from two GPS satellites IGS and COD and to inspect mean VTEC Correlation between the two satellites by the year of 2008. TEC is defined by the integral of electron density in a 1 m 2 column along the signal transmission path. It is an important parameter to monitor possible space weather impacts. The processed and archived data taken from IGS and COD satellites has been imported in to a MATLAB code which gave us the results of the value of VTEC. Results of the two satellites revealed that, Out of the selected equinox and solstice day’s maximum value of TEC is recorded on March 20/2008 over North and South west equator due to the maximum solar radiation reaching to the ionosphere of the Earth. On the contrary, the Minimum peak ionospheric TEC value is recorded on June 21/2008 over south Asia particularly Srilanka and Bangladesh due to emission of low solar radiation. As regards to monthly variations of ionospheric TEC, results of IGS and COD satellites show that highest mean TEC value is recorded on March and July recorded the least peak TEC value. Results regarding to seasonal variation also revealed that E-Season recorded maximum TEC value and least TEC value is recorded on J-Season. The observations of the two satellites also show that the mean TEC value presents stronger solar activity sensitivity at lower-latitude bands than the middle and high latitudes. In general, there was a very high correlation between Mean TEC value recorded by IGS and COD satellites by the year of 2008 in all low, middle and high latitudes. Keywords : IGS and COD satellites, GPS, Ionosphere, Low, middle and high-latitudes, TEC.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"9 1","pages":"141-161"},"PeriodicalIF":0.3,"publicationDate":"2017-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/mejs.v9i2.2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42864819","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}
Majority of the Ethiopian population are dependent on tef ( Eragrostis tef ( Zucc ) trotter) flour to make injera, a staple food in Ethiopia, although injera could be made from different cereals. The price of tef, however, is high and the yield potential of the crop is low. Thus, searching for alternative cheaper grains and developing a blend of different cereal flours that can produce injera of acceptable quality and improved nutritional value would be important. This study was conducted to evaluate the sensory quality of injera made from a blend of different cereals (Tef, barley, sorghum and maize) with differing ratios: 100, 75, 50 and 25%. The sensory evaluation of injera was conducted at Mekelle University in a replicated trial. The results revealed significant differences among the cereal flour blends in injera texture, mouth feeling, suppleness and overall rate, while colour, taste and the appearance of injera surface gas holes were non- significant. Injera made from 100% tef flour got the highest preference rank in terms of the texture, mouth feeling, suppleness and overall ratings. Injera made from 50:50 tef + barley blend was the second best in both texture and suppleness followed by 50:50 tef + sorghum, 50: 50 tef + maize blends and tef + barley + sorghum blend of equal ratio. Similarly, results from blend of tef + barley + maize, tef + sorgum + maize and from the four varietal blends in equal ratios produced very good injera quality. From the study results injera quality ranked next to sole tef (tef + barley, tef + sorghum, tef + maize in 50:50 blends and tef + barley + sorghum in equal ratios) could be used as an alternative option for injera utilization and could provide nutritional and dietary benefits to consumers. Keywords : Sensory attributes, Injera quality, cereal flour blends, Tef, Ethiopia.
{"title":"Effect of Different Cereal Blends on the Quality of Injera a Staple Food in the Highlands of Ethiopia","authors":"A. Abraha, F. Abay","doi":"10.4314/mejs.v9i2.7","DOIUrl":"https://doi.org/10.4314/mejs.v9i2.7","url":null,"abstract":"Majority of the Ethiopian population are dependent on tef ( Eragrostis tef ( Zucc ) trotter) flour to make injera, a staple food in Ethiopia, although injera could be made from different cereals. The price of tef, however, is high and the yield potential of the crop is low. Thus, searching for alternative cheaper grains and developing a blend of different cereal flours that can produce injera of acceptable quality and improved nutritional value would be important. This study was conducted to evaluate the sensory quality of injera made from a blend of different cereals (Tef, barley, sorghum and maize) with differing ratios: 100, 75, 50 and 25%. The sensory evaluation of injera was conducted at Mekelle University in a replicated trial. The results revealed significant differences among the cereal flour blends in injera texture, mouth feeling, suppleness and overall rate, while colour, taste and the appearance of injera surface gas holes were non- significant. Injera made from 100% tef flour got the highest preference rank in terms of the texture, mouth feeling, suppleness and overall ratings. Injera made from 50:50 tef + barley blend was the second best in both texture and suppleness followed by 50:50 tef + sorghum, 50: 50 tef + maize blends and tef + barley + sorghum blend of equal ratio. Similarly, results from blend of tef + barley + maize, tef + sorgum + maize and from the four varietal blends in equal ratios produced very good injera quality. From the study results injera quality ranked next to sole tef (tef + barley, tef + sorghum, tef + maize in 50:50 blends and tef + barley + sorghum in equal ratios) could be used as an alternative option for injera utilization and could provide nutritional and dietary benefits to consumers. Keywords : Sensory attributes, Injera quality, cereal flour blends, Tef, Ethiopia.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"9 1","pages":"232-241"},"PeriodicalIF":0.3,"publicationDate":"2017-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/mejs.v9i2.7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42359695","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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