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4th National Anti-tuberculosis Drug Resistance Survey in Kenya

Journal of Health Science 2017年第6期5卷 282-291页

作者： Joseph Sitienei Kamene Kimenye Josephine Wahogo Bernard Langat Enos Masini obadiah njuguna Jane Ong'ang'o Sophie Matu Jeremiah Okari Maurice Maina Margret Mburu Herman Weyenga Jane Mwangi Lucy Nganga Agnes Langat Abraham Katana Hillary Kipruto Joel Kangangi Division of Leprosy Tuberculosis and Lung Disease Department of Disease Prevention and Control Ministry of Health Nairobi 20781 Kenya Kenya Medical Research Institute [KEMRI] Centre for Respiratory Diseases Research Nairobi 20781 Kenya National TB Reference Laboratory Department of Disease Prevention and Control Ministry of Health Nairobi 20781 Kenya United States Agency for International Development [USAID] Department of Population and Health Kenya and East Africa Office Nairobi 20781 Kenya U.S. Centers for Disease Control and Prevention [CDC] Nairobi 20781 Kenya Worm Health Organization [WHO] Kenya Country Office Nairobi 20781 Kenya

Introduction: Recently rapid development of drug resistant TB, particularly MDR TB (Multi Drug Resistant TB) and XDRTB (Extensively Drug-Resistant TB) possess a major threat to control of tuberculosis globally. Information on the extent of MDR-TB from Kenya is largely limited due to several factors. Monitoring of development of resistance is a vital tool in providing critical information for effective planning for TB control and in management of patients infected with TB. Methods: Cross-sectional with cluster design. Results: A total of 2,171 participants recruited into the study from 50 selected clusters. Prevalence of rifampicin resistance for new cases was 1.3% [95% CI, 0.8-2.0] and INH resistance was 5.5% [95% CI, 4.5-6.7]. MDR TB was found in 0.67% of new cases and 2.1% amongst previously treated TB cases. Discussion: Resistance to isoniazid in Kenya has been on the decline due to introduction of rifampicin in combined therapy. There was increase of MDR TB among new cases by 24% and decline in previously treated cases due to lethal impact of HIV. Conclusions: Although drug resistance TB is a growing problem in Kenya, resistance to isoniazid and rifampicin MDR TB is less than previously estimated. The country should continue to monitor drug resistance and ensure effective use of anti TB medicines.

关键词： Multi drug resistant TB Mycobacterium tuberculosis drug resistance Kenya

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Experimental investigation and optimization of the gasification parameters of macadamia nutshells in a batch-fed bubbling fluidized bed gasifier with air preheating

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Energy Storage and Saving 2023年第4期2卷 559-570页

作者： Fredrick Irungu njuguna Hiram M.Ndiritu Benson B.Gathitu Meshack Hawi Jotham Muthoka Munyalo School of Mechanical Manufacturing and Materials EngineeringJomo Kenyatta University of Agriculture and TechnologyNairobi62000-00200Kenya School of Biosystems and Environmental Engineering Jomo Kenyatta University of Agriculture and TechnologyNairobi62000-00200Kenya

Gasification of biomass waste has a significant potential to reduce environmental impact and promote sustainability by producing syngas,which is considered as renewable *** work investigated the gasification of macadamia nutshells in air-preheated,batch-fed fluidized bed *** study conducted a parametric analysis to assess the effect of equivalence ratio(ER)and air temperature on the gasifier temperature profile and its performance based on gas composition,higher heating value(HHV),and gas *** research was conducted within the range of 0.15-0.35 for the ER and 25-825℃ for the air ***-objective numerical optimization was conducted using response surface methodology(RSM).From the parametric study,a distinct temperature profile was observed along the gasifier height,with the peak temperature near the top of the fluidized bed section and the lowest temperature at the top of the *** preheating mostly favored gasification temperature at the lower part of the gasifier and showed rare significance at the *** improvement in gasifier performance was observed beyond an air temperature of 620℃,which was identified as the ideal air-preheating *** of variance(ANOVA)revealed that the ER was the most influential parameter in the production of combustible gasses,syngas HHV and gas *** preheating did not have a significant effect on methane production and gas *** most optimal values for ER and air temperature were obtained as 0.195℃ and 620℃,respectively,producing optimal values of 9.54,14.65%,2.03,4.02 MJ⋅Nm^(-3),and 1.82 Nm^(3)⋅kg^(-1) for hydrogen,carbon monoxide,methane,HHV,and gas yield,respectively.

关键词： Biomass gasification Air preheating Optimization Response surface methodology

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Examining Rate of Built-Up Areas on the Vegetation Cover along River Riara Riparian within Kiambu Town, Kenya

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Journal of Geoscience and Environment Protection 2022年第3期10卷 144-158页

作者： Charles M. Mugambi Mugwima njuguna Dennis Karanja Centre for Urban Studies Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya Department of Landscape Architecture Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

Urban river riparian spaces and their natural systems are valuable to urban dwellers;but are increasingly affected and ruined by human activities and in particular, urbanization processes. In this research, land sat and sentinel satellite imagery apt for change detection in vegetation cover, both landsat and sentinel imagery, covering the period between 1970 and 2021 in epochs of 1973, 1984, 1993, 2003, 2015 and 2021 years were used to establish the correlation between vegetation cover and built-up area along River Riara river reserve. The images were analysed to extract the built-up areas along the river reserve, including the buildings, and the rate of human settlements, which influenced vegetation cover. Normalized Difference Built-Up Index (NDBI) and Normalized Difference Vegetation Index (NDVI) were computed using the Short-Wave Infrared (SWIR) and the Near Infra-Red (NIR) bands to show the rate of change over the years. Results indicate NDVI values were high, compared to NDBI values along river Riara in the years 1973 and 1993 implying that there was more vegetation cover then. However, in the year 2021, the NDVI indicated the highest value at 0.88, with the complementary NDBI indicating the highest NDBI value at 0.47. This represents a significant increase in built-up areas since 2015 more than in previous epochs. Either, there was a significant increase in NDBI values, from 0.24 in 1993 to 0.47 in 2021. More so, the R-squared value at 0.80 informed 80% relationship between NDBI and NDVI values indicating a negative correlation.

关键词： Ecological Conservation Urban Riparian Reserves Vegetation Cover Index Built-Up Area Index NDVI NDBI

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Construction of Non-Symmetric Balanced Incomplete Block Design through Combination of Symmetric Disjoint Balanced Incomplete Block Designs

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Open Journal of Statistics 2023年第6期13卷 789-802页

作者： Troon John Benedict Onyango Fredrick Karanjah Anthony njuguna Edward Department of Economics Maasai Mara University Narok Kenya Department of Mathematics and Actuarial Science Maseno University Luanda Kenya Department of Mathematics Multimedia University Nairobi Kenya Department of Mathematics and Physical Science Maasai Mara University Narok Kenya

The existence of several non-symmetric balanced incomplete block designs (BIBDs) is still unknown. This is because the non-existence property for non-symmetric BIBDs is still not known and also the existing construction methods have not been able to construct these designs despite their design parameters satisfying the necessary conditions for the existence of BIBD. The study aimed to bridge this gap by introducing a new class of non-symmetric BIBDs. The proposed class of BIBDs is constructed through the combination of disjoint symmetric BIBDs. The study was able to determine that the total number of disjoint symmetric BIBDs (n) with parameters (v = b, r = k, λ) that can be obtained from an un-reduced BIBD with parameters (v, k) is given by n = r - λ. When the n symmetric disjoint BIBDs are combined, then a new class of symmetric BIBDs is formed with parameters v* = v, b* = nb, r* = nr, k* = k, λ* = λ, where 2≤ n ≤ r - λ. The study established that the non-existence property of this class of BIBD was that when is not a perfect square then v should be even and when v* is odd then the equation should not have a solution in integers x, y, z which are not all simultaneously zero. In conclusion, the study showed that this construction technique can be used to construct some non-symmetric BIBDs. However, one must first construct the disjoint symmetric BIBDs before one can construct the non-symmetric BIBD. Thus, the disjoint symmetric BIBDs must exist first before the non-symmetric BIBDs exist.

关键词： Disjoint Symmetric BIBD Un-Reduced BIBD Combination Symmetric BIBD Non-Symmetric BIBD Non-Existence of BIBD

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CD34-Negative B-Lymphoblastic Leukemia/Lymphoma Presenting as Cutenous Lesions at Infancy: A Case Report

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Journal of Biosciences and Medicines 2022年第4期10卷 20-25页

作者： Teresa Lotodo Festus njuguna Samson Kiprono Gilbert Olbara Nicholas Kigen Moi University Eldoret Kenya Moi Teaching and Referral Hospital Eldoret Kenya AMPATH Reference Laboratories Eldoret Kenya

Acute lymphoblastic leukemia/lymphoma is a highly aggressive neoplasm of precursor lymphoid (blast) cells. There are 2 main subtypes based on lymphoid lineage;B lymphoblastic leukemia/lymphoma (B-ALL/LBL) and T lymphoblastic leukemia/lymphoma (T-ALL/LBL). B-ALL/LBL commonly presents with fever, fatigue, bone or joint pain, bleeding or anorexia (signs of bone marrow infiltration), lymphadenopathy, hepatosplenomegaly, involvement of skin, soft tissue and testes, with a predilection for the central nervous system. Immature cell markers, such as CD34 and TdT, can help to differentiate lymphoblasts from Burkitt lymphoma which, is considered a mature high-grade B cell lymphoma that mimics lymphoblastic lymphoma/leukemia. Unfavorable prognostic factors include: infancy and adult age of diagnosis, high white blood cell count, slow response to initial therapy, central nervous system involvement at the time of diagnosis and Minimal residual disease after therapy. We present a case report of a 4 months old infant seen at a Tertiary Hospital with a rare presentation of CD34 Negative B-lymphoblastic leukemia/lymphoma presenting as cutaneous lesions in infancy.

关键词： Lymphoblastic Leukemia Flow Cytometry CD34 Negative Cutaneous Lesions Infancy

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单晶硅衬底对Si-Al合金中块体硅生长的影响

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热加工工艺 2022年第7期51卷 66-71页

作者：张鸣 Benson Kihono njuguna 谭毅李佳艳大连理工大学材料科学与工程学院辽宁大连116024

硅与合金熔体的分离及合金元素的回收再利用一直是限制Si-Al合金凝固精炼工艺进一步应用的关键问题。本文采用温度梯度区域熔炼方法在Si-Al合金中生长块体硅。通过在合金熔体的底部引入单晶硅衬底,研究单晶衬底对于块体硅生长的形貌及... 详细信息

硅与合金熔体的分离及合金元素的回收再利用一直是限制Si-Al合金凝固精炼工艺进一步应用的关键问题。本文采用温度梯度区域熔炼方法在Si-Al合金中生长块体硅。通过在合金熔体的底部引入单晶硅衬底,研究单晶衬底对于块体硅生长的形貌及杂质分布的影响。结果表明,单晶硅衬底的添加降低了合金熔体的温度梯度,块体硅以平直界面向上生长,生长速率明显变慢。在温度梯度2.4 K/mm和生长时间240 min时,块体硅的生长速率由石墨坩埚上的0.108μm/s下降至Si(100)衬底上的0.075μm/s。在相同的温度梯度和生长时间内,块体硅在Si(100)衬底上的生长速率明显快于Si(111)衬底。单晶硅衬底在块体硅生长过程中起到籽晶的作用。

关键词： Si-Al合金单晶硅衬底类单晶硅

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Grain refinement of primary silicon in hypereutectic Al-Si alloys by different P-containing compounds

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China Foundry 2021年第1期18卷 37-44页

作者： Benson Kihono njuguna Jia-yan Li Yi Tan Qian-qian Sun Peng-ting Li School of Materials Science and Engineering Dalian University of TechnologyDalian116024China State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai200444China Shandong Shanda Al&Mg Melt Technology Company Limited Jinan250061China

The grain refinement behavior of Si-3 P,Si-25 Mn-10 P,and Al-10 Si-2 Fe-3 P master alloys on hypereutectic Al-24 Si alloy was *** analysis indicates that the P-containing compounds in the three master alloys are Si P,Mn P,and Al P,*** coarse flower-like primary silicon in the Al-24 Si alloy transforms into smaller,well-distributed blocks with the addition of various master *** pouring at 840°C,the average grain size of the primary silicon refined by Si-25 Mn-10 P master alloy with a holding time of 30 min is about 18μm,which is significantly smaller than those refined by Si-3 P and Al-10 Si-2 Fe-3 P master *** grain size shows an increasing trend when the holding time is further *** holding temperature has a positive effect on the grain refinement of Si-25 Mn-10 P master *** grain refinement mechanism of the three master alloys was also discussed.

关键词： grain refinement primary silicon master alloy AlP compound

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Heredity of Lower Separation Axioms on Function Spaces

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Advances in Pure Mathematics 2014年第3期4卷 89-92页

作者： njuguna E. Muturi Department of Mathematics Egerton University Egerton Kenya

The set of continuous functions from topological space Y to topological space Z endowed with a topology forms the function space. For A subset of Y, the set of continuous functions from the space A to the space Z forms the underlying function space with an induced topology. The function space has properties of topological space dependent on the properties of the space Z, such as the T0, T1, T2 and T3 separation axioms. In this paper, we show that the underlying function space inherits the T0, T1, T2 and T3 separation axioms from the function space, and that these separation axioms are hereditary on function spaces.

关键词： Function Space Underlying Function Space Hereditary Properties

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Influence of Building Information Modelling (BIM) on Engineering Contract Management in Nairobi, Kenya

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World Journal of Engineering and Technology 2020年第3期8卷 329-346页

作者： Hellen Nyaboke Mosse Mugwima njuguna Charles Kabubo Sustainable Materials Research & Technology Centre (SMARTEC) Jomo Kenyatta University of Agriculture and Technology (JKUAT) Nairobi Kenya Centre for Urban Studies Jomo Kenyatta University of Agriculture and Technology (JKUAT) Nairobi Kenya

Building Information Modelling (BIM) is a technology and a process that has brought changes in the construction’s traditional procurement system. Kenya lacks contractual guidelines on implementation of BIM;this makes the adoption of BIM slow and difficult. Previous research has identified a gap in contractual relationships, roles and resulting risks. The objectives of this study were to investigate BIM adoption in Nairobi and to investigate the influence of BIM on Engineering Contract Management (ECM) in Nairobi Kenya. The survey research was a descriptive study with 175 responsive questionnaires. Respondents comprised of Civil Engineers, Construction Project Managers, Architects, Quantity Surveyors, Contractors and Facility Managers. Data was collected through self-administered questionnaire and in-depth interview. Descriptive analytics, correlation and Exploratory factor analysis methods were used to analyse quantitative data. Qualitative data was analysed thematically. It emerged that adoption level was at 56.6% and shallow understanding of BIM capabilities remains to be a barrier to its adoption and implementation. It also emerged that BIM improves ECM;when time, cost, quality, collaboration and return on investment improve, ECM becomes easier. Latent factors found in BIM and ECM relationship were Legal Implications, awareness and knowledge, efficiency, versatility, mandate and leadership, and competitiveness. Further, the study found out that BIM influence on ECM demands for establishment of standards, guidelines, policy, legal framework, and regulations, which can be achieved by amending the public procurement act which dictates the operation of all the other standard forms of contract. Further research should be conducted to measure whether the understanding of BIM had positively improved.

关键词： Building Information Modelling BIM Adoption Implementation Collaboration BIM Contractual Roles and Responsibilities Contract

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压电与磁力协同作用下的电子器件冷却风扇研究

压电与磁力协同作用下的电子器件冷却风扇研究

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作者： Fredrick Irungu njuguna 大连海事大学

学位级别：硕士

本文研制了一个具有多重振动的冷却风扇系统,主要用于电子器件的冷却。该系统由1个压电风扇片和6个磁力风扇片构成,这7个风扇片的端部都装有小磁铁。压电风扇片由交流电驱动,其余6个风扇片由相互之间的排斥力驱动。论文主要研究了风扇... 详细信息

本文研制了一个具有多重振动的冷却风扇系统,主要用于电子器件的冷却。该系统由1个压电风扇片和6个磁力风扇片构成,这7个风扇片的端部都装有小磁铁。压电风扇片由交流电驱动,其余6个风扇片由相互之间的排斥力驱动。论文主要研究了风扇的频率、振幅以及功率消耗,此外,还通过实验研究其冷却能力,采用了两种不同端部形状的风扇片,即,T形和I形。分析了振幅、频率、功耗、对流换热系数以及无量纲换热系数的变化情况。此外,通过CFD仿真分析了稳态下的平均温度,并与实验结果进行对比。同时对流场进行了可视化模拟。对I型风扇片,其尺寸为55×20×0.2毫米,系统在28.5 Hz的频率下,总振动幅度为64毫米;对头部为30毫米宽的T形风扇,在31.2Hz下具有61毫米的振动幅度。单个压电风扇在28 Hz下的振幅为40毫米,消耗功率为0.6W。对T型风扇在31.2 Hz下工作时,热源温度从82.59℃可降至67.51℃,而对于Ⅰ形风扇,在28 Hz下,温度可下降到71.110C。通过CFD的模拟结果可以看出,气流的速度可达1.25 m/s。

关键词：压电式风扇多振动冷却风扇系统传热 CFD模拟

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