High accuracy wind speed forecasting is essential for wind energy harvest and plays a significant role in wind farm management and grid integration. Wind speed is intermittent in nature, which makes the forecasting to be a big challenge. In the present study, three hybrid single-step wind speed forecasting techniques are proposed and tested by local measurement data in Singida region, Tanzania. The three techniques are based on Wavelet Analysis (WA), Back Propagation (BP) optimization algorithm, and Recurrent Neural Network (RNN). They are referred to as WA-RNN, BP-RNN, and WA-BP-RNN. The model results showed that WA-BP-RNN outperforms the other two proposed techniques, with minimum statistical errors of 0.56 m/s (BIAS), 6.89% (MAPE) and 0.53 m/s (RMSE). Furthermore, the WA-BP-RNN technique has shown highest correlation value of 0.95, which indicates that, the strength of a linear association between the observed and forecasted dataset of the wind speed. In addition, the deployment of the BP optimization algorithm in the proposed technique showed improvements of the model results.
高精度的风速预报是风能获取的基础，在风电场管理和电网整合中具有重要作用。风速本质上是间歇性的，这使得预测风速成为一个巨大的挑战。本文提出了三种混合单步风速预报技术，并通过坦桑尼亚Singida地区的实测数据进行了试验。这三种技术分别基于小波分析(WA)、反向传播(BP)优化算法和循环神经网络(RNN)。它们被称为WA-RNN、BP-RNN和WA-BP-RNN。模型结果表明，WA-BP-RNN优于其他两种方法，最小统计误差分别为0.56 m/s (BIAS)、6.89% (MAPE)和0.53 m/s (RMSE)。此外，WA-BP-RNN技术显示出最高的相关值0.95，这表明风速观测数据与预测数据之间存在线性关联的强度。此外，BP优化算法在该技术中的应用表明，模型结果有所改善。
{"title":"Wind Speed Forecasting Using Wavelet Analysis and Recurrent Artificial Neural Networks Based on Local Measurements in Singida Region, Tanzania","authors":"Rajabu J. Mangara, Mwingereza J. Kumwenda","doi":"10.4314/tjs.v49i3.17","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.17","url":null,"abstract":"High accuracy wind speed forecasting is essential for wind energy harvest and plays a significant role in wind farm management and grid integration. Wind speed is intermittent in nature, which makes the forecasting to be a big challenge. In the present study, three hybrid single-step wind speed forecasting techniques are proposed and tested by local measurement data in Singida region, Tanzania. The three techniques are based on Wavelet Analysis (WA), Back Propagation (BP) optimization algorithm, and Recurrent Neural Network (RNN). They are referred to as WA-RNN, BP-RNN, and WA-BP-RNN. The model results showed that WA-BP-RNN outperforms the other two proposed techniques, with minimum statistical errors of 0.56 m/s (BIAS), 6.89% (MAPE) and 0.53 m/s (RMSE). Furthermore, the WA-BP-RNN technique has shown highest correlation value of 0.95, which indicates that, the strength of a linear association between the observed and forecasted dataset of the wind speed. In addition, the deployment of the BP optimization algorithm in the proposed technique showed improvements of the model results.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082914","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}
Victor O. Egbeneje, Samuel E. Okhale, Chinyere Imoisi, Isaac O. Ogbogo, Omolade Ojo
The use of nanoparticles as corrosion inhibitors has gained popularity because of its increased corrosion efficiency due to increase surface to volume ratio. Nanoparticles which undergo physisorption/chemisorption to the corrosion metal surface and inhibit the corrosion efficiently also have low toxicity, low cost and easy production. In this research work, weight lost method was applied to study the inhibitive properties of silver nanoparticles (AgNPs) synthesized using Senna occidentalis root extract as environmentally benign corrosion inhibitor of mild steel in 0.5 M H2SO4 medium at 298 K and 308 K. It was observed that the corrosion rate of the steel sample decreases with increase in concentration of the silver nanoparticles but increased with rise in temperature. The highest inhibition efficiency of 65.59% was obtained at 308 K at the concentration of 5 gdm-3 and the least of 10.58% at the concentration of 1 gdm-3 at 308 K. The decrease in inhibition efficiency with rise in temperature is suggestive of physical adsorption mechanism. The surface coverage was observed to increase with increasing concentration of the nanoparticles and decreased with increase in temperature. This could be as a result of physical adsorption mechanism. The evaluated activation energy was found to be higher for the inhibited process than for the uninhibited process. The increase in apparent activation energy in the presence of the nanoparticles denotes physical adsorption mechanism, while the reverse is usually attributed to chemical adsorption. The negative values of heat of adsorption Qads suggest that the adsorption phenomenon is exothermic.
纳米颗粒作为缓蚀剂的使用越来越受欢迎，因为它增加了表面体积比，从而提高了腐蚀效率。纳米粒子对腐蚀金属表面进行物理吸附/化学吸附，有效抑制腐蚀，而且具有低毒、低成本和易于生产的特点。本研究采用失重法研究了以西泻根提取物为缓蚀剂合成的银纳米颗粒(AgNPs)在0.5 M H2SO4介质中298 K和308 K下对低碳钢的缓蚀性能。结果表明，随着银纳米粒子浓度的增加，钢样品的腐蚀速率降低，而随着温度的升高，钢样品的腐蚀速率增加。在308 K时，5 gdm-3的抑制率最高，为65.59%;在308 K时，1 gdm-3的抑制率最低，为10.58%。抑制效率随温度升高而降低，说明其存在物理吸附机制。表面覆盖率随纳米粒子浓度的增加而增加，随温度的升高而降低。这可能是物理吸附机制的结果。结果表明，受抑制过程的活化能高于未受抑制过程的活化能。纳米粒子存在时表观活化能的增加说明了物理吸附机制，反之则通常归因于化学吸附。吸附热Qads为负值表明吸附现象为放热现象。
{"title":"Evaluation of the Inhibitive Properties of Silver Nanoparticles in Senna occidentalis Root Extract as Corrosion Inhibitor of Mild Steel","authors":"Victor O. Egbeneje, Samuel E. Okhale, Chinyere Imoisi, Isaac O. Ogbogo, Omolade Ojo","doi":"10.4314/tjs.v49i3.9","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.9","url":null,"abstract":"The use of nanoparticles as corrosion inhibitors has gained popularity because of its increased corrosion efficiency due to increase surface to volume ratio. Nanoparticles which undergo physisorption/chemisorption to the corrosion metal surface and inhibit the corrosion efficiently also have low toxicity, low cost and easy production. In this research work, weight lost method was applied to study the inhibitive properties of silver nanoparticles (AgNPs) synthesized using Senna occidentalis root extract as environmentally benign corrosion inhibitor of mild steel in 0.5 M H2SO4 medium at 298 K and 308 K. It was observed that the corrosion rate of the steel sample decreases with increase in concentration of the silver nanoparticles but increased with rise in temperature. The highest inhibition efficiency of 65.59% was obtained at 308 K at the concentration of 5 gdm-3 and the least of 10.58% at the concentration of 1 gdm-3 at 308 K. The decrease in inhibition efficiency with rise in temperature is suggestive of physical adsorption mechanism. The surface coverage was observed to increase with increasing concentration of the nanoparticles and decreased with increase in temperature. This could be as a result of physical adsorption mechanism. The evaluated activation energy was found to be higher for the inhibited process than for the uninhibited process. The increase in apparent activation energy in the presence of the nanoparticles denotes physical adsorption mechanism, while the reverse is usually attributed to chemical adsorption. The negative values of heat of adsorption Qads suggest that the adsorption phenomenon is exothermic.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082646","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}
Melania A. Nyimbo, Ronald J. Massawe, Michael M. Msabi
Kaolin is a commercial clay material composed of hydrated aluminosilicate mineral kaolinite and used in various industrial applications such as ceramics, paper, paints, refractories, fiberglass, plastics, cosmetics and pharmaceuticals. It is formed as a result of strong chemical weathering of crystalline and feldspar-rich rocks or hydrothermal alteration of granitic rocks at relatively low temperature and pressure conditions. The kaolin deposit of Matamba originated from the weathering of leucogabbro rock during the development of the African land surface. In view of highlighted properties, the mineralogy and chemical characteristics of the Matamba kaolin deposit were investigated to determine its industrial applications. As part of the study approach, forty-six (46) samples were collected and analyzed for major oxides using X-ray fluorescence (XRF) and mineralogical composition using X-ray diffraction (XRD). The XRD results indicated that the Matamba kaolin is dominantly composed of kaolinite (10.1–100%) with other phases such as albite (1.2–56.8%), oligoclase (10.1–54.3%), quartz (1.2–33.9%), goethite (1.0–9.4%) and muscovite (1.1–29.5%). The dominant major oxides are SiO2 (39.78–67.96 wt.%), Al2O3 (14.60–38.07 wt.%) and subordinate amounts of Fe2O3 (0.93–6.37 wt.%), MgO (1.42–4.74 wt.%), Na2O (0.10–1.09 wt.%), K2O (0.14–2.01 wt.%), CaO (0.08–0.99 wt.%), TiO2 (0.07–1.66 wt.%), P2O5 (0.36–1.77 wt.%) and LOI (1.91–13.97 wt.%). These major oxides correlate with the mineralogical composition supporting kaolinite dominance. Consequently, compared with some industrial specifications, these results indicate that Matamba kaolin deposit may be useful for ceramic products, refractories such as fireclay crucibles and electrolytic production of aluminium and its alloys. However, it should be beneficiated and upgraded to improve some technical properties to qualify for other industrial applications.
{"title":"Mineralogy and Geochemical Characteristics of Matamba Kaolin Deposit-Njombe Region South-Western Tanzania: Implications for Industrial Applications","authors":"Melania A. Nyimbo, Ronald J. Massawe, Michael M. Msabi","doi":"10.4314/tjs.v49i3.12","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.12","url":null,"abstract":"Kaolin is a commercial clay material composed of hydrated aluminosilicate mineral kaolinite and used in various industrial applications such as ceramics, paper, paints, refractories, fiberglass, plastics, cosmetics and pharmaceuticals. It is formed as a result of strong chemical weathering of crystalline and feldspar-rich rocks or hydrothermal alteration of granitic rocks at relatively low temperature and pressure conditions. The kaolin deposit of Matamba originated from the weathering of leucogabbro rock during the development of the African land surface. In view of highlighted properties, the mineralogy and chemical characteristics of the Matamba kaolin deposit were investigated to determine its industrial applications. As part of the study approach, forty-six (46) samples were collected and analyzed for major oxides using X-ray fluorescence (XRF) and mineralogical composition using X-ray diffraction (XRD). The XRD results indicated that the Matamba kaolin is dominantly composed of kaolinite (10.1–100%) with other phases such as albite (1.2–56.8%), oligoclase (10.1–54.3%), quartz (1.2–33.9%), goethite (1.0–9.4%) and muscovite (1.1–29.5%). The dominant major oxides are SiO2 (39.78–67.96 wt.%), Al2O3 (14.60–38.07 wt.%) and subordinate amounts of Fe2O3 (0.93–6.37 wt.%), MgO (1.42–4.74 wt.%), Na2O (0.10–1.09 wt.%), K2O (0.14–2.01 wt.%), CaO (0.08–0.99 wt.%), TiO2 (0.07–1.66 wt.%), P2O5 (0.36–1.77 wt.%) and LOI (1.91–13.97 wt.%). These major oxides correlate with the mineralogical composition supporting kaolinite dominance. Consequently, compared with some industrial specifications, these results indicate that Matamba kaolin deposit may be useful for ceramic products, refractories such as fireclay crucibles and electrolytic production of aluminium and its alloys. However, it should be beneficiated and upgraded to improve some technical properties to qualify for other industrial applications.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082769","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}
Felista W. Mwingira, Deokary J. Matiya, Neema G. Mogha
Malaria remains a public health problem in Tanzania, escalated by the emergence of both parasite and vector resistance. Plant-based traditional medicines have been widely utilized as alternatives to malaria management. However, proper documentation is minimal, especially among the younger generation. This study assessed the knowledge of medicinal plants for malaria management among 532 Dar es Salaam University College of Education students. Overall, twenty-four plant species, most belonging to the family Asteraceae, were identified with Azaradichta indica being the most dominant species. These results reveal a substantial knowledge of medicinal plants for malaria management among university students.
{"title":"Ethnobotanical Survey on the Knowledge and Use of Medicinal Plants for Malaria Management among University Students","authors":"Felista W. Mwingira, Deokary J. Matiya, Neema G. Mogha","doi":"10.4314/tjs.v49i3.2","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.2","url":null,"abstract":"Malaria remains a public health problem in Tanzania, escalated by the emergence of both parasite and vector resistance. Plant-based traditional medicines have been widely utilized as alternatives to malaria management. However, proper documentation is minimal, especially among the younger generation. This study assessed the knowledge of medicinal plants for malaria management among 532 Dar es Salaam University College of Education students. Overall, twenty-four plant species, most belonging to the family Asteraceae, were identified with Azaradichta indica being the most dominant species. These results reveal a substantial knowledge of medicinal plants for malaria management among university students.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082902","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}
John Pyuza Gunda, Alexander Pogrebnoi, Baraka Kichonge
Post-harvest losses of fruits and vegetables pose significant challenges, especially in tropical climates. This study introduces the development and performance evaluation of a solar-powered evaporative cooling storage system integrated with ultraviolet light (UV) designed for preservation of perishable fruits and vegetables. The cooling chamber supplied with ultraviolet lamp was developed using locally available materials such as sisal, sponge, and bricks. The performance of the system was evaluated in terms of air temperature decrease, relative humidity increase, and evaporative cooling power capacity both for sunny and cloudy tropical weather conditions. The study reveals that activating the UV light considerably extends the shelf life of fruits and vegetables. The system was able to extend the shelf life of perishable products by up to 21 days when exposed to ultraviolet light and by 9 days when not exposed to ultraviolet light. On sunny days, active system operation leads to an average temperature reduction of 5.0 °C, along with a relative humidity increase of 23%. On the contrary, on cloudy days, the cooling impact diminishes slightly, resulting in temperature decrease of approximately 3.5 °C and relative humidity increase of 18%. These findings emphasize the potential of the solar-powered evaporative cooling system, combined with UV light treatment, as a viable approach to combat post-harvest losses in tropical environments.
{"title":"Design of a Cooling System Integrated with Ultraviolet Light for Preservation of Fruits and Vegetables at Variable Tropical Weather Conditions: A Case Study of Arusha, Tanzania","authors":"John Pyuza Gunda, Alexander Pogrebnoi, Baraka Kichonge","doi":"10.4314/tjs.v49i3.16","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.16","url":null,"abstract":"Post-harvest losses of fruits and vegetables pose significant challenges, especially in tropical climates. This study introduces the development and performance evaluation of a solar-powered evaporative cooling storage system integrated with ultraviolet light (UV) designed for preservation of perishable fruits and vegetables. The cooling chamber supplied with ultraviolet lamp was developed using locally available materials such as sisal, sponge, and bricks. The performance of the system was evaluated in terms of air temperature decrease, relative humidity increase, and evaporative cooling power capacity both for sunny and cloudy tropical weather conditions. The study reveals that activating the UV light considerably extends the shelf life of fruits and vegetables. The system was able to extend the shelf life of perishable products by up to 21 days when exposed to ultraviolet light and by 9 days when not exposed to ultraviolet light. On sunny days, active system operation leads to an average temperature reduction of 5.0 °C, along with a relative humidity increase of 23%. On the contrary, on cloudy days, the cooling impact diminishes slightly, resulting in temperature decrease of approximately 3.5 °C and relative humidity increase of 18%. These findings emphasize the potential of the solar-powered evaporative cooling system, combined with UV light treatment, as a viable approach to combat post-harvest losses in tropical environments.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082637","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}
As one of the most grown seasonal fruit, tomato is widely consumed for making food products, drugs and ornaments. However, poor post-harvest handling system, transport and storage facilities deteriorate the quality of tomato fruits resulting into post-harvest losses. These problems have been addressed by the use of nanotechnology in this study. The combination of a chitosan surface and the core shell chitin results into novel deacetylated chitin nanofibril (DeChNF) with good biological activity and mechanical strength. The effectiveness of the DeChNF films for food preservation as an alternative material to chitosan is investigated. The DeChNF with degree of acetylation (DA) = 60.2% and chitosan (DA = 7.1%) were obtained from crab shells. Two appraches were employed to store freshly matured tomatoes harvested at a breaker stage. The tomatoes were coated with the colloidal suspension and wrapped in the films. Flexible wrapping films were prepared from the colloidal suspension through solution casting using bees honey (35%) and compared to those with glycerol (25%) as plastisizers. The main output storage parameters analysed include colour development, surface spoilage, and weight loss over 20 days at a 73% relative humidity. Tomatoes covered with DeChNF-honey and chitosan-honey films remained in good condition after 20 days, while the coated samples lasted for up to 15 days, except those coated with DeChNF, and those covered with a polyethylene films or stored in a refrigerator at 9 °C. The samples covered with DeChNF films plasticized with honey showed the best resistance against weight loss. The tensile strength of the DeChNF-honey films (strength = 21.32 MPa) and the chitosan-honey films (strength = 21.86 MPa) were higher than the polyethylene films (10.9 MPa). The current work increases understanding on DeChNF as an alternative material, with additional of honey as a plasticizer, over the superior chitosan, or commercial films based on fossil resources.
{"title":"Effective Enhancement of Post-Harvest Tomato Storage through Wrapping Using Deacetylated Chitin Nanofibril-Plasticized Honey Films","authors":"Ngesa Ezekiel Mushi, Edina Meela, Divina Kaombe","doi":"10.4314/tjs.v49i3.14","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.14","url":null,"abstract":"As one of the most grown seasonal fruit, tomato is widely consumed for making food products, drugs and ornaments. However, poor post-harvest handling system, transport and storage facilities deteriorate the quality of tomato fruits resulting into post-harvest losses. These problems have been addressed by the use of nanotechnology in this study. The combination of a chitosan surface and the core shell chitin results into novel deacetylated chitin nanofibril (DeChNF) with good biological activity and mechanical strength. The effectiveness of the DeChNF films for food preservation as an alternative material to chitosan is investigated. The DeChNF with degree of acetylation (DA) = 60.2% and chitosan (DA = 7.1%) were obtained from crab shells. Two appraches were employed to store freshly matured tomatoes harvested at a breaker stage. The tomatoes were coated with the colloidal suspension and wrapped in the films. Flexible wrapping films were prepared from the colloidal suspension through solution casting using bees honey (35%) and compared to those with glycerol (25%) as plastisizers. The main output storage parameters analysed include colour development, surface spoilage, and weight loss over 20 days at a 73% relative humidity. Tomatoes covered with DeChNF-honey and chitosan-honey films remained in good condition after 20 days, while the coated samples lasted for up to 15 days, except those coated with DeChNF, and those covered with a polyethylene films or stored in a refrigerator at 9 °C. The samples covered with DeChNF films plasticized with honey showed the best resistance against weight loss. The tensile strength of the DeChNF-honey films (strength = 21.32 MPa) and the chitosan-honey films (strength = 21.86 MPa) were higher than the polyethylene films (10.9 MPa). The current work increases understanding on DeChNF as an alternative material, with additional of honey as a plasticizer, over the superior chitosan, or commercial films based on fossil resources.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082905","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}
Furahini Yoram, Nazima Dharsee, Khamza Maunda, Jumaa D. Kisukari, Geofrey F. Soko
This study assessed the efficiency of offline setup correction protocol and the use of a thermoplastic mask for head and neck cancer (HNC) patients treated with three-dimensional conformal radiotherapy at Ocean Road Cancer Institute. A prospective study was conducted from April to August 2021 to verify 62 patients’ treatment setup using an offline setup correction protocol while immobilized with a thermoplastic mask. Megavoltage images were matched with digitally reconstructed radiographs obtained during CT simulation to determine the gross set-up deviations. Box plots were used to show the deviations on three consecutive days of the first week and a successive weekly set-up verification in lateral, longitudinal, and vertical directions. The associations between thermoplastic mask types and weekly deviations were analyzed using repeated test ANOVA. A p-value ˂ 0.05 was considered statistically significant. The observed deviations after the use of correction protocol were lower in all three translational directions. There was no statistical significance between types of thermoplastic mask and setup deviations in lateral (p < 0.65), longitudinal (p = 0.19), and vertical (p = 0.12) directions. The offline correction protocol can be used in settings with limited resources and high workloads of patients. Both types of thermoplastic masks are effective in immobilizing HNC patients.
{"title":"Assessment of the Offline Setup Correction Protocol and Thermoplastic Mask Use for Head and Neck Cancer Radiotherapy: A Single Institution Experience","authors":"Furahini Yoram, Nazima Dharsee, Khamza Maunda, Jumaa D. Kisukari, Geofrey F. Soko","doi":"10.4314/tjs.v49i3.13","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.13","url":null,"abstract":"This study assessed the efficiency of offline setup correction protocol and the use of a thermoplastic mask for head and neck cancer (HNC) patients treated with three-dimensional conformal radiotherapy at Ocean Road Cancer Institute. A prospective study was conducted from April to August 2021 to verify 62 patients’ treatment setup using an offline setup correction protocol while immobilized with a thermoplastic mask. Megavoltage images were matched with digitally reconstructed radiographs obtained during CT simulation to determine the gross set-up deviations. Box plots were used to show the deviations on three consecutive days of the first week and a successive weekly set-up verification in lateral, longitudinal, and vertical directions. The associations between thermoplastic mask types and weekly deviations were analyzed using repeated test ANOVA. A p-value ˂ 0.05 was considered statistically significant. The observed deviations after the use of correction protocol were lower in all three translational directions. There was no statistical significance between types of thermoplastic mask and setup deviations in lateral (p < 0.65), longitudinal (p = 0.19), and vertical (p = 0.12) directions. The offline correction protocol can be used in settings with limited resources and high workloads of patients. Both types of thermoplastic masks are effective in immobilizing HNC patients.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082907","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}
Over the years, wireless communication has significantly improved the data rate of mobile users. The key drive behind this success is the technological advancement in wireless communication. In the physical layer, hybrid beamforming has revolutionized the way signal reaches the user by constructively adding the signal at the destination thus improving the performance. Many researchers works have proposed different algorithms to solve for optimal hybrid beamforming. However, there is no single algorithm that can achieve both high spectral efficiency and energy efficiency at the same time. This work proposes a hybrid algorithm that combines successive interference cancellation and water filling and applies this algorithm in overlapped sub-array architecture (OSA). The former can successfully optimize for analog precoding in a subarray environment as it eliminates the interference between the successive sub-arrays. While the latter can allocate the power in each data stream proportionally, thus improving the spectral efficiency. The simulation results show that the proposed algorithm with OSA can achieve a near optimal performance in comparison to fully connected hybrid beamforming (FCH) and significantly larger performance in comparison to partially connected hybrid beamforming (PCH). Moreover, the proposed algorithm achieves 89.2% energy efficiency in comparison to PCH architecture. These results show that an OSA system with the proposed algorithm provides a better tradeoff between achieved spectral efficiency (SE) and energy efficiency (EE).
{"title":"An Overlapped Sub-array Hybrid Beamforming Architecture with Successive Interference Cancellation and Water-filling in Massive MIMO Systems","authors":"Godwin Mruma Gadiel","doi":"10.4314/tjs.v49i3.5","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.5","url":null,"abstract":"Over the years, wireless communication has significantly improved the data rate of mobile users. The key drive behind this success is the technological advancement in wireless communication. In the physical layer, hybrid beamforming has revolutionized the way signal reaches the user by constructively adding the signal at the destination thus improving the performance. Many researchers works have proposed different algorithms to solve for optimal hybrid beamforming. However, there is no single algorithm that can achieve both high spectral efficiency and energy efficiency at the same time. This work proposes a hybrid algorithm that combines successive interference cancellation and water filling and applies this algorithm in overlapped sub-array architecture (OSA). The former can successfully optimize for analog precoding in a subarray environment as it eliminates the interference between the successive sub-arrays. While the latter can allocate the power in each data stream proportionally, thus improving the spectral efficiency. The simulation results show that the proposed algorithm with OSA can achieve a near optimal performance in comparison to fully connected hybrid beamforming (FCH) and significantly larger performance in comparison to partially connected hybrid beamforming (PCH). Moreover, the proposed algorithm achieves 89.2% energy efficiency in comparison to PCH architecture. These results show that an OSA system with the proposed algorithm provides a better tradeoff between achieved spectral efficiency (SE) and energy efficiency (EE).","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135083032","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}
Alex Saturday, Thomas J. Lyimo, Siajali Pamba, Susan Kangume, Jeniffer Turyatemba
Lake Bunyonyi ecosystem plays vital roles in water resource conservancy and tourism. Nevertheless, the rapid increase in human population and the unrelenting human activities are threatening the values, functions, and ecological integrity of the lake. In this study, the public perceptions of drinking water quality and its health implications in the Lake Bunyonyi Sub-catchment, Western Uganda are presented. A closed-ended questionnaire was administered to 267 respondents living within one Kilometre away from the lake shores. Besides, observation and interview methods were used to complement data collected by the questionnaire method. Results indicate that the prominent activities around the lake are peasantry and small-scale businesses attributed to soil fertility and rural tourism. Despite the lake being a popular source of drinking water in the sub-catchment, the quality of its water suffers from diffuse pollution and little has been done to avert it. This study recommends regular surveillance and water quality testing to increase people’s awareness of water quality. Besides, the local authorities should train people the alternative environmentally-friendly farming practices like afforestation with correct tree species and agro-forestry practices to increase vegetation cover and reduce soil erosion debris washed into the lake system. Environmental-friendly household water treatment methods (biosand filtration and solar disinfection) should be promoted to improve the quality of drinking water.
{"title":"Public Perceptions of Water Quality in the Lake Bunyonyi Sub-Catchment, Western Uganda","authors":"Alex Saturday, Thomas J. Lyimo, Siajali Pamba, Susan Kangume, Jeniffer Turyatemba","doi":"10.4314/tjs.v49i3.15","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.15","url":null,"abstract":"Lake Bunyonyi ecosystem plays vital roles in water resource conservancy and tourism. Nevertheless, the rapid increase in human population and the unrelenting human activities are threatening the values, functions, and ecological integrity of the lake. In this study, the public perceptions of drinking water quality and its health implications in the Lake Bunyonyi Sub-catchment, Western Uganda are presented. A closed-ended questionnaire was administered to 267 respondents living within one Kilometre away from the lake shores. Besides, observation and interview methods were used to complement data collected by the questionnaire method. Results indicate that the prominent activities around the lake are peasantry and small-scale businesses attributed to soil fertility and rural tourism. Despite the lake being a popular source of drinking water in the sub-catchment, the quality of its water suffers from diffuse pollution and little has been done to avert it. This study recommends regular surveillance and water quality testing to increase people’s awareness of water quality. Besides, the local authorities should train people the alternative environmentally-friendly farming practices like afforestation with correct tree species and agro-forestry practices to increase vegetation cover and reduce soil erosion debris washed into the lake system. Environmental-friendly household water treatment methods (biosand filtration and solar disinfection) should be promoted to improve the quality of drinking water.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082770","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}
Rukia J. Mwifunyi, Daudi C. Mnyanghwalo, Shamte J. Kawambwa
The increased dependence on the electric power grid, coupled with the increasing number of new customers, motivates the need to improve the reliability and resilience of the electric distribution systems. Modern distribution systems are becoming more resilient against power outages due to the increasing integration of Distributed Energy Resources (DERs) and the availability of efficient mechanisms for load shedding. Several studies considered fault detection and Service Restoration (SR) as separate problems without considering the implementation feasibility of integrating both solutions. To ensure the resiliency in the power system, it is important to have proper mechanisms which integrate sensing, detection, and SR as one problem while considering the load shedding and DER for improved capacity. Hence, this study proposed an IoT-based-sensor network framework with an enhanced algorithm coupled with a Binary Bat metaheuristic algorithm for SR integrating sensing, detection, and restoration. The proposed algorithms have been tested in Tanzania's electrical distribution network, considering the inclusion of DERs and load shedding. The results showed that DERs' size and locations significantly impact restoration schemes' performance with a power loss reduction of 74%. Therefore, efficient SR schemes should consider optimal DERs placement and a combination of load shedding and DERs integration for improved performance.
{"title":"Enhancing Service Restoration in Tanzanian Power Grid using Internet of Things Sensors and Renewable Energy Sources","authors":"Rukia J. Mwifunyi, Daudi C. Mnyanghwalo, Shamte J. Kawambwa","doi":"10.4314/tjs.v49i3.10","DOIUrl":"https://doi.org/10.4314/tjs.v49i3.10","url":null,"abstract":"The increased dependence on the electric power grid, coupled with the increasing number of new customers, motivates the need to improve the reliability and resilience of the electric distribution systems. Modern distribution systems are becoming more resilient against power outages due to the increasing integration of Distributed Energy Resources (DERs) and the availability of efficient mechanisms for load shedding. Several studies considered fault detection and Service Restoration (SR) as separate problems without considering the implementation feasibility of integrating both solutions. To ensure the resiliency in the power system, it is important to have proper mechanisms which integrate sensing, detection, and SR as one problem while considering the load shedding and DER for improved capacity. Hence, this study proposed an IoT-based-sensor network framework with an enhanced algorithm coupled with a Binary Bat metaheuristic algorithm for SR integrating sensing, detection, and restoration. The proposed algorithms have been tested in Tanzania's electrical distribution network, considering the inclusion of DERs and load shedding. The results showed that DERs' size and locations significantly impact restoration schemes' performance with a power loss reduction of 74%. Therefore, efficient SR schemes should consider optimal DERs placement and a combination of load shedding and DERs integration for improved performance.","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135082775","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：