The impacts of hydropower development on rural livelihood sustenance

The existing reservoirs on the River Tana (Kenya) were mainly constructed for hydropower generation, with inadequate consideration of the long-term impacts on downstream livelihoods. We investigated the impacts of the reservoirs on people's livelihoods downstream. The results showed a few positive impacts in the vicinity of the reservoirs and numerous negative impacts downstream (i.e. reduced flood-recess agriculture and floodplain pastoralism, and escalating resource-use conflicts). Inadequate stakeholders' consultation during reservoir development was also observed. We recommend a detailed basin-wide socioeconomic assessment for future reservoir developments and controlled flood release to simulate the natural flow regime, thereby restoring indigenous flood-based livelihoods while retaining sufficient reserves for power generation.     

The cutting-wrapping problem in the textile industry: Optimal overlap of fabric lengths and defects for maximizing return based on quality

This paper deals with an important problem in the last phase of manufacturing in the textile industry. This involves cutting large lengths of fabric into smaller pieces, which are then wrapped around rolls. The quality of cloth rolls transported to the customer is specified by the quality of fabric pieces that make up the roll. A piece of fabric falls within a given quality category if some of its characteristics, such as, piece length, the number of critical defects per metre, and the defective score per metre, are compatible with the corresponding quality specifications. Naturally, the selling price per metre of fabric is proportional to the quality category. Thus, it becomes necessary to determine an optimal cutting strategy of very long woven fabric (e.g. 2000 m) into smaller pieces (e.g. each 130 m long at most), which involves a difficult continuous assignment problem of identifying the optimal cutting locations of pieces overlapping with defects of known lengths and locations. Not only must the scrap be minimized but the overall profit per metre fabric should be maximized. The two objectives may not always support each other due to relative unit selling prices of various quality categories. The solution to this problem has an immediate impact on company profit. The mathematical formulation of the problem involves numerous binary variables as well as continuous variables. A Mutative Simulated Annealing approach is proposed here to solve this problem. The solution technique is tested both on real data obtained from a textile manufacturer and hypothetical data. Results are compared against upper bounds calculated for each objective defined, as well as with a sequential heuristic designed for this problem.     

Growth, Optical, Mechanical, Dielectric and Theoretical Studies on Potassium Pentaborate Tetrahydrate (KB_5O_8·4H_2O) Single Crystal by Modified Sankaranarayanan-Ramasamy Method

A nonlinear optical single crystal of potassium pentaborate tetrahydrate (KB5O8·4H2O) has been grown from aqueous solution by using unidirectional crystal growth method of Sankaranarayanan-Ramasamy (SR) with a due modification in the growth assembly. Potassium pentaborate crystal of 60 mm length and 10 mm diameter has been grown along (100) plane with a growth rate of 3 mm per day within a period of 20 days. The grown crystal was subjected to single crystal X-ray diffraction analysis to confirm that the cry...     

Influence of CTAB surfactant on structural and optical properties of CuS and CdS nanoparticles by hydrothermal route

Metal sulphide CuS and CdS nanoparticles capped with Cetyltrimethylammonium bromide (CTAB) were synthesized by hydrothermal method. Structural, morphological, chemical composition, optical and luminescent properties were evaluated by different analytical techniques. X-ray diffraction (XRD) analysis of the CTAB capped metal sulfide nanoparticles reveals the formation of hexagonal structure. High-resolution transmission electron microscopy (HRTEM) images show that the morphology of the capped copper sulphide samples consists of hexagonal structure and capped cadmium has spherical shape and also confirms the crystalline nature of the particles with distinct lattice fringes. In FTIR spectroscopy, the composition of the CTAB capped CuS and CdS nanoparticles have been confirmed. The analysis of photoluminescence (PL) and optical transition show a red shift due to the reduction of band gap energy and it is attributed to the low defects and high crystallinity. The optical studies indicate that CuS and CdS nanoparticles with CTAB can be suitable for optoelectronic devices and photovoltaic applications.     

One-step conversion of syngas to light olefins over bifunctional metal-zeolite catalyst

Light olefins(C_2–C_4) are fundamental building blocks for the manufacture of polymers, chemical intermediates,and solvents. In this work, we realized a composite catalyst, comprising Mn_xZr _yoxides and SAPO-34 zeolite,which can convert syngas(CO + H_2) into light olefins. Mn_xZr_yoxide catalysts with different Mn/Zr molar ratios were facilely prepared using the coprecipitation method prior to physical mixing with SAPO-34 zeolite. The redox properties, surface morphology, electronic state, crystal structure, and chemical elemental composition of the catalysts were examined using H_2-TPR, SEM, XPS, XRD, and EDS techniques, respectively. Tandem reactions involved activation of CO and subsequent hydrogenation over the metal oxide catalyst, producing methanol and dimethyl ether as the main reaction intermediates, which then migrated onto SAPO-34 zeolite for light olefins synthesis. Effects of temperature, pressure and reactant gas flow rate on CO conversion and light olefins selectivity were investigated in detail. The Mn_1Zr_2/SAPO-34 catalyst(Mn/Zr ratio of 1:2) attained a CO conversion of 10.8% and light olefins selectivity of 60.7%, at an optimized temperature, pressure and GHSV of 380 °C, 3MPa and 3000 h~(-1) respectively. These findings open avenues to exploit other metal oxides with CO activation capabilities for a more efficient syngas conversion and product selectivity.     

Investment Model for Power Generation and Transmission Network Expansion in Turkey

Provision of adequate electricity is one of the major factors for industrial and commercial development. However, decisions on the expansion of electricity are bogged down by high investment requirements and nonsynchronized expansion between electricity generation and transmission systems. As a rule, the investment requirements for these types of projects are immediate but their benefits can be obtained only in the long-term basis albeit electricity planners base their decisions on immediate requirements of shorter terms. As investment funds are very hard to come by, the funds, if available, should be utilized to maximum by minimizing the investment through a synchronized expansion planning of both electricity generation and transmission systems. This paper attempts to address this opportunity. We have proposed here a mixed integer model to develop concurrent transmission and generation investments plans. The model selects new generation plants or generation capacity expansions for existing plants that are located on the interconnected network by considering explicitly congestion in the transmission network. Hence the model contributes to this area by filling in the gap between models for developing long-term power generation policies and power flow models focusing on transmission network expansion. The application of the model in Turkey’s electricity network highlights the country’s congested areas in the transmission network, which might lead to loss of load and inefficient generation capacity expansion if not tackled properly. The analysis shows that a cost efficient generation expansion is possible to realize in congested regions if proper transmission expansion decisions are made concurrently with generation expansion decisions.     

Evidence that childhood acute lymphoblastic leukemia is associated with an infectious agent linked to hygiene conditions

OBJECTIVES: The incidence of acute lymphoblastic leukemia (ALL) in children has shown temporal and geographic variation during the 20th century, with higher rates in developed nations appearing in the first half of the century, but with persisting low rates in developing nations. We sought to assess the relation of childhood ALL with hygiene conditions, an aspect of socioeconomic development affecting rates of exposure to infectious agents. METHODS: Infection patterns for hepatitis A virus (HAV), an agent with a fecal-oral route of transmission, were used to indicate hygiene conditions in different populations, with emphasis on instructive United States and Japanese data. A catalytic model was fit to these data, estimating the HAV force of infection and age-specific seroprevalence rates over time. These analyses were used to assess the temporal relationship of changes in HAV infection rates to changes in childhood leukemia mortality and incidence rates. RESULTS: We observed an inverse relationship between HAV infection prevalence and rates of childhood leukemia. Further, decreases in the HAV force of infection in the United States and Japan appear to have preceded increases in childhood leukemia rates. We describe a model based on a putative leukemia-inducing agent with a change in infection rate over time correlated with that of HAV that describes well the temporal trends in childhood leukemia rates for White children in the US and for Japanese children. CONCLUSION: The data suggest that improved public hygiene conditions, as measured by decreased prevalence of HAV infection, are associated with higher childhood ALL incidence rates. The model that we present supports the plausibility of the hypothesis that decreased childhood exposure to a leukemia-inducing agent associated with hygiene conditions leads to higher rates of ALL in children by increasing the frequency of in utero transmission caused by primary infection during pregnancy (or by increasing the number of individuals infected in early infancy because of lack of protective maternal antibodies).     

A novel approach to data collection in a case-control study of cancer and occupational exposures

BACKGROUND: In community and hospital-based case-control studies, the occupational data collected in interviews are usually limited to responses to general questions asked of all study subjects. A procedure is described in which more detailed information can be collected in an efficient, standardized and systematic way. METHODS: A generic work history is initially collected from all subjects using a computer-assisted interview. The work history includes job title, type of business, job activities, materials and chemicals, and tools and equipment used. After responses are entered into the computer by the interviewer, the computer searches a synonym file to identify possible job-specific modules relevant to the reported job. The modules are detailed questionnaires that address specific jobs administered after obtaining the generic work history. The modules are used to ask questions about the work environment; sources of exposure; factors affecting the movement of the agent from the source to the subject, such as local exhaust ventilation; and individual and job characteristics. After the interview is completed, the work history and responses to the modules are sent electronically to an industrial hygienist who reviews the information using a custom-designed software package. Where ambiguities or contradictions occur in information reported by the respondent, or for jobs for which no module had been developed, the industrial hygienist generates up to 10 additional questions per job. These questions are sent back to the interviewer for administration of a short, second interview. CONCLUSIONS: These procedures, which are being successfully implemented in an on-going case-control study of brain tumours, should improve disease risk estimates over those derived from more traditional approaches to exposure assessment.     

Investigations on the nucleation studies of sodium paranitrophenolate dihydrate single crystal

Solubility, metastable zonewidth and induction period have been estimated for the growth of sodium paranitrophenolate dihydrate (NPNa) single crystal. The interfacial energy has been calculated using experimentally determined induction period values. Nucleation parameters such as Gibbs free energy, critical energy barrier, radius, number of molecules in the critical nucleus and growth rate have been calculated. The evaluated interfacial tension values are found to be well agreed with the theoretical value derived from the solubility data. Bulk single crystals of NPNa have been grown with an aid of methanol as a solvent by slow evaporation technique.