检索结果-南通市图书馆

Towards Increasing Data Availability for Meteorological Services: Inter-Comparison of Meteorological Data from a Synoptic Weather Station and Two Automatic Weather Stations in Kenya

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Climate Change 2021年第3期10卷 300-316页

作者： Richard Muita Paul Kucera Stella Aura David Muchemi David Gikungu samuel mwangi Martin Steinson Paul Oloo Nicholas Maingi Ezekiel Muigai Mwaura Kamau Kenya Meteorological Department Institute for Meteorological Training and Research Nairobi Kenya University Corporation for Atmospheric Research/National Centre for Atmospheric Research (UCAR/NCAR) Boulder USA

Meteorological data is useful for varied applications and sectors ranging from weather and climate forecasting, landscape planning to disaster management among others. However, the availability of these data requires a good network of manual meteorological stations and other support systems for its collection, recording, processing, archiving, communication and dissemination. In sub-Saharan Africa, such networks are limited due to low investment and capacity. To bridge this gap, the National Meteorological Services in Kenya and few others from African countries have moved to install a number of Automatic Weather Stations (AWSs) in the past decade including a few additions from private institutions and individuals. Although these AWSs have the potential to improve the existing observation network and the early warning systems in the region, the quality and capacity of the data collected from the stations are not well exploited. This is mainly due to low confidence, by data users, in electronically observed data. In this study, we set out to confirm that electronically observed data is of comparable quality to a human observer recorded data, and can thus be used to bridge data gaps at temporal and spatial scales. To assess this potential, we applied the simple Pearson correlation method and other statistical tests and approaches by conducting inter-comparison analysis of weather observations from the manual synoptic station and data from two Automatic Weather Stations (TAHMO and 3D-PAWS) co-located at KMD Headquarters to establish existing consistencies and variances in several weather parameters. Results show there is comparable consistency in most of the weather parameters between the three stations. Strong associations were noted between the TAHMO and manual station data for minimum (r = 0.65) and maximum temperatures (r = 0.86) and the maximum temperature between TAHMO and 3DPAWS (r = 0.56). Similar associations were indicated for surface pressure (r = 0.99) and R

关键词： Meteorological Data Manual Weather Station Automatic Weather Station Correlation

Growth Parameters of DK8031 Maize Variety as Affected by Varying Irrigation and Nitrogen Fertilizer Rates in Embu County, Kenya

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Science and Engineering(A) 2015年第8期4卷 432-444页

作者： Charles Nyambane Onyari Antony mwangi Kibe samuel Mwonga Department of Land and Water Management Embu University EMB U 6-60100 Kenya Department of Crops Horticulture and Soils Egerton University EGERTON 536 Kenya

Determination of crop growth parameters of maize helps assess the performance of the crop for food security. A study was conducted in two seasons covering 2012 and 2013 to establish optimal irrigation and nitrogen fertilizer rates for drought tolerant hybrid maize （Zea mays L.）, DK8031 variety, in sandy loam soils using furrow irrigation. Four additive irrigation levels （119.05 mm, 238.10 mm, 357.15 mm and 476.2 mm） were allocated the main plots while five nitrogen fertilizer rates （0 kg/ha, 60, 75 kg/ha, 90 kg/ha and 100 kg/ha） were allocated the sub-plots. Both irrigation and nitrogen fertilizer treatments significantly enhanced crop growth parameters under consideration. Stand count per treatment plot, plant height and number of leaves per ranged from 45-59 plants/plot, 215-238 cm and 14-16 leaves respectively. It was concluded that use of supplementary irrigation and phased nitrogen fertilizer rates for maize growing in areas such as Embu can greatly promote crop growth.

关键词： Maize irrigation nitrogen fertilizer rates plant height leaves per plant.

Serotypes and Antimicrobial Susceptibility Patterns of Nasopharyngeal Pneumococci Isolated from HIV-Infected Children in Selected Pediatric Clinics in Nairobi, Kenya

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Medical Microbiology 2016年第1期6卷 42-52页

作者： Catherine N. mwangi Gunturu Revathi Anne W. Muigai samuel Kariuki Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya Aga Khan University Hospital Nairobi Kenya Kenya Medical Research Institute Nairobi Kenya

Background: Streptococcus pneumoniae (pneumococcus) is one of the most frequent causes of bacterial infection in children and is a leading cause of otitis, sinusitis, pneumonia, and meningitis worldwide. Nasopharyngeal colonization is a risk factor for pneumococcal disease, a leading cause of complications and death in infants. HIV-infected persons are at high risk of invasive pneumococcal disease. Method: Nasopharyngeal swabs were collected from 296 HIV infected children below five years recruited from Gertrude’s Children hospital and Nazareth Hospital Nairobi, Kenya. The nasopharyngeal swabs were processed to isolate S. pneumoniae, which were serotyped and tested for drug susceptibility. Results: The carriage prevalence of S. pneumoniae in the study was 30.4% while the isolated serotypes were (in order of decreasing frequency): 35B, 19F, 3, 13, 15A, 11A, 16F, 7C and 23A. Most of the serotypes were resistant to the commonly used antibiotics but all were susceptible to vancomycin and chloramphenicol. Conclusion: Carriage prevalence of nasopharyngeal S. pneumonia in HIV infected children was lower than that of similar prevalence studies in children. Most of the S. pneumoniae isolates were however non pneumococcal vaccine isolates.

关键词： Streptococcus pneumoniae Nasopharynx Serotypes HIV Children PCV

Optimization of Extrusion Process Parameters of Recycled High-Density Polyethylene-Thermoplastic Starch Composite for Fused Filament Fabrication

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Composite Materials 2023年第4期13卷 69-86页

作者： Grace Njeri Wamuti James Wamai mwangi samuel Kabini Karanja Leif Micke Henning Zeidler Pan African University Institute of Basic Sciences Technology and Innovation Nairobi Republic of Kenya Department of Mechatronic Engineering Jomo Kenyatta University of Agriculture and Technology Nairobi Republic of Kenya Chair of Additive Manufacturing Technische Universit&aumlt Bergakademie Freiberg Freiberg Germany

High-density poly-ethylene (HDPE) is a nonbiodegradable recyclable plastic which is widely utilized in single use packaging applications. Consequently, it constitutes a significant amount of plastic waste found in landfills. From literature, it has been shown that parts produced using composites of HDPE with carbohydrate-based polymers, such as thermoplastic starch (TPS), experience mechanical degradation through hydrolytic degradation process. The possible utilization of recycled-HDPE (rHDPE) and TPS composite in nonconventional manufacturing processes such as Fused filament fabrication (FFF) has however not been explored. This study explores the potential application of rHDPE and TPS composites in FFF and optimizes the extrusion process parameters used in rHDPE-TPS filament production process. Taguchi method was utilized to analyze the extrusion process. The extrusion process parameters studied were the spooling speed, extrusion speed and the extrusion temperatures. The response variable studied was the filament diameter. In this research, the maximum TPS content achieved during filament production was 40 wt%. This filament was however challenging to use in FFF printers due to frequent nozzle clogging. Printing was therefore done with filaments that contained 0 - 30 wt% TPS. The experimental results showed that the most significant parameter in extrusion process was the spooling speed, followed by extrusion speed. Extrusion temperature had the least significant influence on the filament diameter. It was observed that increase in TPS content resulted in reduced warping and increased rate of hydrolytic degradation. Mechanical properties of printed parts were investigated and the results showed that increasing TPS content resulted in reduction in tensile strength, reduction in compression strength and increase in stiffness. The findings of this research provide valuable insights to plastic recycling industries and researchers regarding the utilization of recycled HDP

关键词： Additive Manufacturing (AM) Fused Filament Fabrication (FFF) High Density Polyethylene (HDPE) Thermoplastic Starch (TPS) Bio-Composite

Characterization and Modeling of Mechanical Properties of Additively Manufactured Coconut Fiber-Reinforced Polypropylene Composites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2024年第6期14卷 95-112页

作者： George Mosi Bernard W. Ikua samuel K. Kabini James W. mwangi Department of Mechatronic Engineering Jomo Kenyatta University of Agriculture and Technology Juja Kenya

In the face of the increased global campaign to minimize the emission of greenhouse gases and the need for sustainability in manufacturing, there is a great deal of research focusing on environmentally benign and renewable materials as a substitute for synthetic and petroleum-based products. Natural fiber-reinforced polymeric composites have recently been proposed as a viable alternative to synthetic materials. The current work investigates the suitability of coconut fiber-reinforced polypropylene as a structural material. The coconut fiber-reinforced polypropylene composites were developed. Samples of coconut fiber/polypropylene (PP) composites were prepared using Fused Filament Fabrication (FFF). Tests were then conducted on the mechanical properties of the composites for different proportions of coconut fibers. The results obtained indicate that the composites loaded with 2 wt% exhibited the highest tensile and flexural strength, while the ones loaded with 3 wt% had the highest compression strength. The ultimate tensile and flexural strength at 2 wt% were determined to be 34.13 MPa and 70.47 MPa respectively. The compression strength at 3 wt% was found to be 37.88 MPa. Compared to pure polypropylene, the addition of coconut fibers increased the tensile, flexural, and compression strength of the composite. In the study, an artificial neural network model was proposed to predict the mechanical properties of polymeric composites based on the proportion of fibers. The model was found to predict data with high accuracy.

关键词： Additive Manufacturing Artificial Neural Network Mechanical Properties Natural Fibers Polypropylene