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Voids size distribution in gelled waxy crude oil under dynamic and static cooling

Petroleum Research 2024年第1期9卷 109-114页

作者： girma T.Chala Shaharin A.Sulaiman Department of Mechanical Engineering(Well Engineering) International College of Engineering and ManagementP.O.Box 2511C.P.O Seeb 111MuscatOman Department of Mechanical Engineering Universiti Teknologi PETRONASBandar Seri Iskandar37500TronohPerakMalaysia

Waxy crude oil is known for its high wax contents that can potentially result in gelling following sufficient cooling of the transportation line in the subsea bed at offshore *** gelling over the entire lines requires an accurately predicted restart pressure to restart the clogged and idle ***,the common way of predicting the restart pressure has been reported to result in over-designed and predicted piping *** research findings evidenced the formation of voids which would reduce the restart pressure *** study conducted in this paper is aimed at investigating the voids size distribution in gelled crude oil across and along transportation *** of experiments simulating crude oil transportation during both static and dynamic cooling were *** gelled crude oil below the pour point temperature was then scanned using a Magnetic Resonance Imaging(MRI)system to detect the voids *** resulting voids at each scanning cross-section were quantified,and their distributions were *** was observed that dynamic cooling had minimal impacts on the voids size difference along the pipeline with the difference in voids areas within 10 mm^(2) to be twice and uniform for the entire flow rates ***,voids size in statically cooled waxy crude oil was found to be highly distributed with a maximum of 6 voids size distribution in 10 mm2 *** low-end temperature had the highest size difference while the difference was decreasing with higher end *** study shows that the voids amount in dynamically cooled waxy crude oil could also be estimated with lower numbers of cross-sectional voids ***,the higher cross-sectional voids detection is recommended while estimating voids in statically cooled waxy crude oil.

关键词： Gelled crude oil Voids size distribution Dynamic cooling Static cooling

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Public Perception on the Role of Urban Green Infrastructure Development and Land Use Management in Rapidly Urbanized Countries:The Case of Hawassa City,Ethiopia

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Fudan Journal of the Humanities and Social Sciences 2024年第1期17卷 73-113页

作者： Mefekir Woldegebriel Tessema Birhanu girma Abebe Ethiopian Institute of Architecture Building Construction and City Development(EiABC)Addis Ababa UniversityAddis AbabaEthiopia

Urban green areas are essential elements of cities and contribute to the quality of life in numerous ways by maintaining and regulating the ***,increased urbanization and development have placed urban green areas under extreme pressure,while unplanned urban growth has resulted in the loss of urban landscape and *** study’s objective was the public perception on the role of urban green infrastructure and land use *** 385 sample households were selected by using random sampling *** and econometric analyses were used for analyzing both quantitative and qualitative data by using SPSS version *** the major factors influencing the urban green infrastructure by respondents perception were education,income,family size,sex of respondent,marital status,type of employment,ownership of house,participation on public involvement,and frequency of visit to nearer planning which are significant variables in the *** visited the given green structure at least twice a week,and those not done it were 47.9% and 52.1%.The amount of individuals who visited it twice a week in positive perceivers was 64%,and the amount of those who have not done it was 36%.The Chi-square value of 10.9 was very big and telling us that the frequency of visit was determinant factor of *** is vital to keep in mind that while the built-up area and the agricultural areas are rising due to urbanization,the core-ecosystem land is being“eaten”as a result of the past and present land uses inside the administrative limits,as well as the services they *** the last 6 years,the rate at which the most precious ecosystems are disappearing has *** population,which reflects the demand for these services and benefits,is still growing,putting more strain on the *** recommendations include:Public involvement in urban green space planning and development was determinant and core variable of the *** government of the

关键词： Public perceptions Land use/land cover changes Green infrastructure Recreational areas Hawassa city

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新闻剪辑阅读新闻集锦,提升词汇能力

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空中英语教室（高级版．彭蒙惠英语） 2024年第8期 16-18,42,43页

作者： Lebawit Lily girma Adele Peters 不详

酒店房价上涨最快的城市根据一份最新报告指出,从波士顿到孟买,全球各大城市的酒店房价预计将以两位数的百分比升,即使曾经预测酒店房价已经涨到最高点美国运通全球商务旅行集团发布的《2024年酒店监测报告》显示,布宜诺斯艾利斯摘得今... 详细信息

酒店房价上涨最快的城市根据一份最新报告指出,从波士顿到孟买,全球各大城市的酒店房价预计将以两位数的百分比升,即使曾经预测酒店房价已经涨到最高点美国运通全球商务旅行集团发布的《2024年酒店监测报告》显示,布宜诺斯艾利斯摘得今年桂冠,年涨幅达17%。这份报告研究了全球80多个城市的酒店价格波动情况,预测标准包括当前的挂牌价格、更广泛的宏观经济趋势、酒店开发渠道和历史数据。

关键词：商务旅行房价上涨美国运通监测报告大城市新闻集锦宏观经济历史数据

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Evaluation of modified adaptive k-means segmentation algorithm

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Computational Visual Media 2019年第4期5卷 347-361页

作者： Taye girma Debelee Friedhelm Schwenker Samuel Rahimeto Dereje Yohannes Institute of Neural Information Processing Ulm University89081UlmGermany Addis Ababa Science and Technology University Addis Ababa120611Ethiopia

Segmentation is the act of partitioning an image into different regions by creating boundaries between regions.k-means image segmentation is the simplest prevalent ***,the segmentation quality is contingent on the initial parameters(the cluster centers and their number).In this paper,a convolution-based modified adaptive k-means(MAKM)approach is proposed and evaluated using images collected from different sources(MATLAB,Berkeley image database,VOC2012,BGH,MIAS,and MRI).The evaluation shows that the proposed algorithm is superior to k-means++,fuzzy c-means,histogrambased k-means,and subtractive k-means algorithms in terms of image segmentation quality(Q-value),computational cost,and *** proposed algorithm was also compared to state-of-the-art learning-based methods in terms of IoU and MIoU;it achieved a higher MIoU value.

关键词： clustering modified adaptive k-means(MAKM) segmentation Q-value

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Effect of border planting of Eucalyptus citriodora Hook. on the growth and biomass production performance of Cymbopogon winterianus Jowitt ex Bor Grass at Wondo Genet,Southern Ethiopia

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Journal of Forestry Research 2019年第2期30卷 639-646页

作者： Berhanu girma Sisay Feleke Abdu Abdulkadir Department of Forestry College of Agriculture Wollo University Forest Resource Utilization Research Division Ethiopian Environment and Forest Research Institute Wondo Genet College of Forestry and Natural Resources Hawassa University

The use of Eucalyptus trees, in association with other plants, has the potential to reduce the growth of neighbouring plants or grasses by competing for resources or releasing allelochemicals that may cause other plants to grow slowly. Our purpose here is to assess whether border planting of Eucalyptus is harmful to the establishment,growth, and production of Cymbopogon winterianus at various distances from tree lines in the Wondo Genet Agricultural Research Center in Southern Ethiopia. Several factors were studied: growth performances and yield of aromatic grasses; soil properties, including total nitrogen,organic carbon, and moisture content; and plant leaf nutrient content(NPK) at various distances away from the Eucalyptus citriodora border line were studied. Chemical compositions of hydro-distilled essential oils obtained from selected C. winterianus grasses leaves were analysed by gas chromatography. Plant height, biomass yield, amount of essential oil yield, and essential oil composition all were significantly affected due to Eucalyptus effect in the first10-m distance as compared to beyond 10 m from the tree border line. There were increases in soil total nitrogen,organic carbon, and moisture content with decreasing distances to the Eucalyptus tree border. The result of plant leaf nutrient content(NPK) differed across treatment and distance. The pot experiment(15 cm 9 20 cm), shoot length,and number of leaves of aromatic plants varied in the degree of inhibition based on the concentration of the aqueous extract. Significantly higher inhibitions of the shoot length and number of leaf parameters were observed when using 25% fresh leaf extract compared to other extract levels.

关键词： Allelopathic Aqueous extracts Cymbopogon winterianus Eucalyptus citriodora

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Modeling effects of abiotic factors on the abundances of eight woody species in the Harana forest using artificial networks,random forest,and generalized linear models

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Ecological Processes 2023年第1期12卷 151-164页

作者： girma Ayele Bedane Gudina Legese Feyisa Feyera Senbeta Wakjira Center for Environmental Science College of Computational and Natural ScienceAddis Ababa UniversityP.O.Box 1176Addis AbabaEthiopia Centre for Environment and Development College of Development StudiesAddis Ababa UniversityAddis AbabaEthiopia

Background Abiotic factors exert different impacts on the abundance of individual tree species in the forest but little has been known about the impact of abiotic factors on the individual plant,particularly,in a tropical *** study identified the impact of abiotic factors on the abundances of Podocarpus falcatus,Croton macrostachyus,Celtis africana,Syzygium guineense,Olea capensis,Diospyros abyssinica,Feliucium decipenses,and Coffea arabica.A systematic sample design was used in the Harana forest,where 1122 plots were established to collect the abundance of *** forest(RF),artificial neural network(ANN),and generalized linear model(GLM)models were used to examine the impacts of topographic,climatic,and edaphic factors on the log abundances of woody *** RF model was used to predict the spatial distribution maps of the log abundances of each *** The RF model achieved a better prediction accuracy with R^(2)=71%and a mean squared error(MSE)of 0.28 for Feliucium *** RF model differentiated elevation,temperature,precipitation,clay,and potassium were the top variables that influenced the abundance of *** ANN model showed that elevation induced a nega-tive impact on the log abundances of all woody *** GLM model reaffirmed the negative impact of elevation on all woody species except the log abundances of Syzygium guineense and Olea *** ANN model indicated that soil organic matter(SOM)could positively affect the log abundances of all woody *** GLM showed a similar positive impact of SOM,except for a negative impact on the log abundance of Celtis africana at p<*** spatial distributions of the log abundances of Coffee arabica,Filicium decipenses,and Celtis africana were confined to the eastern parts,while the log abundance of Olea capensis was limited to the western *** The impacts of abiotic factors on the abundance of woody species may vary with *** ecological underst

关键词： Species distribution model Random forest Artificial neural network Generalized linear model Species abundance Woody species Environmental variable

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Spatial distribution of above ground carbondensity in Harana Forest,Ethiopia

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Ecological Processes 2022年第1期11卷 14-26页

作者： girma Ayele Bedane Gudina Legese Feyisa Feyera Senbeta Center for Environmental Science College of Computational and Natural ScienceAddis Ababa UniversityP.O.Box No.1176Addis AbabaEthiopia Centre for Environment and Development College of Development StudiesAddis Ababa UniversityAddis AbabaEthiopia

Background:The need for understanding spatial distribution of forest aboveground carbon density(ACD)hasincreased to improve management practices of forest *** study examined spatial distribution of theACD in the Harana Forest.A grid sampling technique was employed and three nested circular plots were establishedat each point where grids ***-related data were collected from 1122 plots while the ACD of each plotwas estimated using the established allometric *** variables in raster format were downloadedfrom open sources and resampled into a spatial resolution of 30 *** statistics were computed to summarize the ACD.A Random Forest classification model in the R-software package was used to select strong predictors,and to predict the spatial distribution of ***:The mean ACD was estimated at 131.505 ton per ha in this study *** spatial prediction showed thatthe high class of the ACD was confined to eastern and southwest parts of the Harana *** Moran’s statisticsdepicted similar observations showing the higher clustering of ACD in the eastern and southern parts of the *** higher ACD clustering was linked with the higher species richness,species diversity,tree density,tree height,clay content,and ***,the lower ACD clustering in the Harana Forest was associated with higher soilcation exchange capacity,silt content,and ***:The spatial distribution of ACD in this study area was mainly influenced by attributes of the forest standand edaphic factors in comparison to topographic and climatic *** findings could provide basis for bettermanagement and conservation of aboveground carbon storage in the Harana Forest,which may contribute to Ethiopia’s strategy of reducing carbon emission.

关键词： Aboveground carbon density Spatial modeling Prediction Random Forest Cluster Pattern

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Larvicidal activities of chinaberry,neem and Bacillus thuringiensis israelensis(Bti) to an insecticide resistant population of Anopheles arabiensis from Tolay,Southwest Ethiopia

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Asian Pacific Journal of Tropical Biomedicine 2016年第7期6卷 554-561页

作者： Assalif Demissew Meshesha Balkew Melaku girma Department of Medicine College of Medicine and Health SciencesAmbo University Aklilu Lemma Institute of Pathobiology Addis Ababa University Human Health Malaria Control DepartmentInternational Center of Insect Physiology and Ecology

Objective:To elucidate the larvicidal potency of neem, chinaberry and Bacillus thuringiensis israelensis(Bti) to larvae of Anopheles arabiensis under semi-field condition and adult susceptibility/resistance to the conventionally used insecticides in Tolay,Southwestern ***: Wild collected 3rd and 4th stage larvae were exposed to neem, and chinaberry seed powder dissolved in water and Bti in artificial containers at three treatment levels:0.2, 0.1 and 0.05 g/m^2 and controls were free of treatments. Larval and pupal mortalities were monitored daily and residual activities were determined. The experiments were replicated three times. The World Health Organization tube test for all classes of insecticides was conducted on adult Anopheles arabiensis reared from field collected larvae and pupae. Data were analyzed using STATA software version ***: In the first application, neem powder caused 88.9%, 87.9% and 79.4% larval and pupal mortality at 0.2, 0.1 and 0.05 g/m^2 after 4.3, 6.0 and 5.7 days, respectively. The corresponding killing effect of chinaberry was 80.3%, 62.1% and 30.3% after 7.0, 7.7 and 8.3days respectively. Bti at all treatments killed 100% after 24 h except 2.7 days for 0.05 g/m^*** mosquitoes were susceptible only for fenitrothion and pirimiphos-methyl with 100%mortality while resistant to deltamethrin, alpha-cypermethrin, etofenprox and dichlorodiphenyl-tricgloroethane with only 9.0%, 3.0%, 5.1% and 2.0% mortalities ***: Neem, chinaberry and Bti showed potent larvicidal and pupicidal activities. However, in the area, high level of mosquito resistance to pyrethroids and dichlorodiphenyl-tricgloroethane was seen which will pose serious challenge to vector control in the future. Therefore, using integrated approach including these botanical larvicides is warranted to manage insecticide resistance.

关键词： Larvicide Anopheles arabiensis Tolay Insecticide Resistance Botanical Bio-efficacy

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Electrochemical Biosensors for Detecting Microbial Toxins by Graphene‑Based Nanocomposites

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Journal of Analysis and Testing 2018年第1期2卷 20-25页

作者： girma Selale Geleta Zhen Zhao Zhenxin Wang State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Chinese Academy of Sciences Beijing 100039China

It is important to develop methods to determine microbial toxins at trace levels since these toxins are ubiquitous commonly found in water and foods,and pose potential threats to both human health and ecosystem *** the advantages of ultrahigh electron-transfer capability,extra-large surface area and easily functionalized ability,the graphene-based nanocomposites have been employed to fabricate electrochemical biosensors including immunosensors and aptasensors for detecting microbial toxins with high *** specificity and selectivity of the electrochemical biosensors for targeting toxins can be achieved by combining graphene nanocomposites with antibodies and/or *** graphene nanocompositebased electrochemical biosensors could become a promising technique in the detection of microbial toxins for public and environmental health protection.

关键词： Graphene nanocomposites Electrochemical immunosensors Electrochemical aptasensors Microbial toxins

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Purification,application and current market trend of natural graphite:A review

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International Journal of Mining Science and Technology 2019年第5期29卷 671-689页

作者： Allah D.Jara Amha Betemariam girma Woldetinsae Jung Yong Kim School of Materials Science and Engineering Jimma Institute of TechnologyJimma UniversityJimma P.O.Box 378Ethiopia Defense Engineering College Bishoftu P.O.Box 1041Ethiopia The Ministry of Mines Petroleum and Natural GasAddis Ababa P.O.Box 486Ethiopia School of Chemical Engineering Jimma Institute of TechnologyJimma UniversityJimma P.O.Box 378Ethiopia

Graphite has a stacked planar sp2-hybridized C6 ring structure,displaying a polymorphism with rhombohedral,hexagonal,and *** on its structure-property relationship,it affords a variety of technologically innovative applications or performances in industries,such as lithium-ion batteries,fuel cells,two dimensional graphene,water purification,electronics,fiber optics,spintronics,refractories,electrical products,electric vehicles,*** monetary value of graphite depends largely on carbon content and flake ***,the physical separation of graphite from its ore body is known to be very expensive,energy intensive and ***,this study extensively describes a current purification method for producing high-quality graphite material with impurities reaching about 10–100 mg/kg,attracting a lot of end *** also describes the potential applications of graphite materials and identifies the future scope of a new market,depending on material ***,the current and future graphite-mining countries are investigated in details.

关键词： Graphite Purification Graphene Lithium-ion battery Market Technology

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