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Performance of Smallholder Dairy Farming in Nak.ru County, k.nya

Journal of Agricultural Science and Technology(A) 2012年第4期2卷 481-488页

作者： Dennis k.nambuga benjamin k. mutai George Owuor Aquilars M. k.lio Emmanuel k. k.nuthia Department of Agricultural Economics and Agribusiness Management University of Egerton Njoro 536-20115 Kenya International Livestock.Research Institute （ILRI） Market Opportunities Nairobi 30709-00100 Kenya

The k.nya dairy sub-sector has been undergoing developments since the 1980s in the areas of adoption of intensive dairy farming, especially zero grazing. There have been concerted efforts by the government and other development partners to commercialize the sub-sector so as to mak. it more profitable to farmers, especially smallholder farmers, but the profitability in the sector continues to be variable with some smallholder farmers mak.ng losses. The causes of the varying profits have not been empirically established, with the influence of institutional arrangements and financial factors contributing to this inconsistency not fully established. This study dwelt on establishing the critical institutional arrangements and financial factors that constrain the profitability of smallholder dairy farmers in Nak.ru County. A multi-stage sampling procedure was used to select respondents. Data were collected by structured interviews at the farm level. Data Envelopment Analysis （DEA） was used to come up with profit efficiency rank.ngs among the farmers, and the Frontier Model was used to establish the factors that constrain profit efficiency. The mean efficiency according to the results was 86%. The farm and farmer characteristics that were significant in explaining profitability efficiency according to the frontier results were： feeding system, breed type, and gender. The financial characteristics included debt amount and debt asset ratio. Additionally, issues of trust were also found to have an effect on profitability, and they included trust in local buyer price, trust in unit of measurement of institutional buyer, and trust in unit of measurement of middlemen.

关键词： Profitability data envelopment analysis dairy farming smallholder

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3D Seismic Analysis of the Gas Hydrate System and the Fluid Migration Paths in Part of the Niger Delta Basin, Nigeria

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Journal of Ocean University of China 2017年第6期16卷 1027-1034页

作者： Ak.NSANPE Olumuyiwa T. ADEPELUMI Adek.nle A. benjamin Uzochuk.u k. FALEBITA Dele E. Department of Geology Obafemi Awolowo University Ile-Ife 220282 Nigeria

Comprehensive qualitative and semi-quantitative seismic analysis was carried out on 3-dimensional seismic data acquired in the deepwater compressional and shale diapiric zone of the Niger Delta Basin using an advanced seismic imaging tool. The main aim of this work.is to obtain an understanding of the forming mechanism of the gas hydrate system, and the fluid migration paths associated with this part of the basin. The results showed the presence of pock.ark. on the seafloor and bottom simulating reflectors(BSRs) in the field, indicating the active fluid flux and existence of gas hydrate system in the area. In the area of approximately 195 k.^2 occupying nearly 24% of the entire study field, three major zones with continuous or discontinuous BSRs of 3 to 7 k. in length which are in the northeastern, southern and eastern part of the field respectively were delineated. The BSR is interpreted to be the transition between the free gas zone and the gas hydrate zone. The geologic structures including faults(strik.-slip and normal faults), chimneys and diapirs were deduced to be the main conduits for gas migration. It is concluded that the biogenic gases generated in the basin were possibly transported via faults and chimneys by advection processes and subsequently accumulated under low temperature and high pressure conditions in the free gas zone below the BSR forming gas hydrate. A plausible explanation for the presence of the ubiquitous pock.ark. of different diameters and sizes in the area is the transportation of the excessive gas to the seafloor through these mapped geologic structures.

关键词： pock.ark bottom simulating reflector gas hydrate Niger Delta Basin

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养殖废水中磷鸟粪石结晶法回收潜力及影响因子研究

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中国生态农业学报（中英文） 2022年第8期30卷 1346-1354页

作者： Erick.k.mutai 王选马林中国科学院农业水资源重点实验室/河北省土壤生态学重点实验室/中国科学院遗传与发育生物学研究所农业资源研究中心石家庄050022 中国科学院大学北京100049 中国科学院雄安创新研究院雄安新区071700

磷作为生命所必需的营养物质因其不可再生性、资源消耗和浪费导致的环境水体富营养化而引起人们的广泛关注。大量研究通过鸟粪石结晶技术从无机合成废水和真实废水中进行磷素回收,降低水体富营养化风险,并形成磷酸镁铵肥料。然而,鸟粪... 详细信息

磷作为生命所必需的营养物质因其不可再生性、资源消耗和浪费导致的环境水体富营养化而引起人们的广泛关注。大量研究通过鸟粪石结晶技术从无机合成废水和真实废水中进行磷素回收,降低水体富营养化风险,并形成磷酸镁铵肥料。然而,鸟粪石结晶过程只涉及无机磷,而真实废水中有机磷含量高达总磷的30%~40%,导致鸟粪石结晶技术在实际应用中磷素回收率变异极大。目前,鸟粪石结晶法在真实废水与无机合成废水中磷回收率差距的量化分析缺乏,导致差异产生的机制和影响因子不明。本研究从103篇文献中收集了1186项观测数据,定量分析了在真实废水与无机合成废水中鸟粪石结晶磷回收率,解析了磷回收差距的潜在影响因子。结果表明,鸟粪石结晶法对无机合成废水中总磷的去除率(83.6%)高于真实废水(76.9%)。在真实废水中,鸟粪石结晶对pH和钙等外来离子更敏感,导致其总磷去除率变异较大,在20.4%和99.9%之间。镁离子和钙离子是影响鸟粪石结晶的重要因子,当Mg∶P比在1和2之间时,镁离子对鸟粪石结晶有积极的影响,而钙离子的存在对鸟粪石的形成有抑制作用。磷结晶沉淀作为一种非生物过程,有机磷矿化是总磷回收的限制因素。因此,曝气在有机磷矿化过程中起着重要作用,额外提供6 L∙min^(−1)的曝气流量有利于提高总磷和无机磷的回收率。提高镁磷比并不是提高磷回收率的关键因素,但对鸟粪石的组成和纯度具有显著影响。

关键词：磷回收鸟粪石无机合成废水真实废水

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Implementation of Interrogation Systems for Fiber Bragg Grating Sensors

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Photonic Sensors 2013年第3期3卷 283-288页

作者： benjamin VARGHESE P. Dinesh k.MAR R. Mittu RAJU k. N. MADHUSOODANAN Department of Instrumentation Cochin University of Science and Technology Cochin lndia

The development of two simple methods for wavelength-optical intensity modulation techniques for fiber Bragg grating （FBG） sensors is presented. The performance is evaluated by measuring the strain and temperature. The first method consists of a narrow band source, an optical circulator, an FBG; and a power meter. The source and Bragg reflected signal from the FBG need to be matched to get linear results with good power levels. The source spectral power levels are very critical in this study. The power reflected from a matched reference FBG is fed into the measuring FBG in the second method. Since the FBGs are matched, the entire power is reflected back.initially. During the measurement, the change in the measurand causes the reflected power from the sensing FBG to vary. A costly high resolution spectrum analyzer is required only during the characterization of the FBG and source. The performances of two interrogators are compared by measuring the strain and temperature. In the second method, the strain measurements can be made insensitive to the temperature variation by selecting a source with a flat spectrum at the measurement range. Highlights of these methods are the portability, cost effectiveness and better resolution.

关键词： Fiber Bragg grating interrogator reflected power strain and temperature measurement

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Structural characterization of carboxyl cellulose nanofibers extracted from underutilized sources

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Science China(Technological Sciences) 2019年第6期62卷 971-981页

作者： ZHAN ChengBo SHARMA Priyank. R. GENG LiHong SHARMA Sunil k. WANG RuiFu JOSHI Ritik. HSIAO benjamin S. Department of Chemistry Stony Brook University Stony Brook NY 11794-3400 USA National Engineer Research Center of Novel Equipment for Polymer Processing Key Laboratory of Polymer Processing Engineering of Ministry of Education South China University of Technology Guangzhou 510640 China

Two different chemical methods, TEMPO-oxidation and nitro-oxidation, were used to extract carboxyl cellulose nanofibers(CNFs) from non-wood biomass sources(i.e., jute, soft and hard spinifex grasses). The combined TEMPO-oxidation and homogenization approach was very efficient to produce CNFs from the cellulose component of biomass;however, the nitrooxidation method was also found to be effective to extract CNFs directly from raw biomass even without mechanical *** effect of these two methods on the resulting cross-section dimensions of CNFs was investigated by solution small-angle Xray scattering(SAXS), transmission electron microscopy(TEM) and atomic force microscopy(AFM). The UV-Vis spectroscopic data from 0.1 wt% TEMPO-oxidized nanofiber(TOCNF) and nitro-oxidized nanofiber(NOCNF) suspensions showed that TOCNF had the highest transparency(> 95%) because of better dispersion, resulted from the highest carboxylate content(1.2 mmol/g). The consistent scattering and microscopic results indicated that TOCNFs from jute and spinifex grasses possessed rectangular cross-sections, while NOCNFs exhibited near square cross-sections. This study revealed that different oxidation methods can result in different degrees of biomass exfoliation and different CNF morphology.

关键词： cellulose nanofibers TEMPO-oxidation nitro-oxidation SAXS microscopy jute spinifex

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