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81.
This paper describes some basic considerations in the design and development of a horizontal axis windmill intended primarily
for irrigation in small farms from shallow open wells. This windmill has six triangular sails sweeping a circle of 10 m diameter
and is an adaptation from Greek sail windmills. For the construction of this windmill all efforts were made to use materials
and parts readily available in the hardware market except for the gear boxes. The cost of material and the parts is Rs. 7,000/-
excluding the cost of machining and fabrication. Preliminary performance tests have indicated a pumping rate of 6000–11000
litres/hr over a head of 6.85 m in wind speeds of 10–16 km/hr. 相似文献
82.
The administration of calcitonin (4 MRC units injected intraperitoneally daily for 42 days) caused hypocalcaemia, hypophosphataemia and a decrease in the serum acid phosphatase level in adult Indian palm squirrels, Funambulus pennanti. Hypocalcaemia and the decrease in the serum acid phosphatase level persisted up to 21 days but the hypophosphataemic effect continued throughout the experiment. The serum calcium level increased from day 28 up to day 35 and the serum acid phosphatase level reached the control level at 28 days. At the close of the experiment (42 days), both serum calcium and acid phosphatase levels were again decreased. Calcitonin-induced hypocalcaemia resulted in hypertrophy of calcitonin cells which were densely packed with secretory granules up to day 21 of the treatment. Thereafter they displayed both hypertrophy and hyperplasia till the end of the experiment. Some calcitonin cells showed degranulation after 35 and 42 days of treatment. Few lead-haematoxylin-positive calcitonin cells with collapsed membranes and pyknotic nuclei were also seen in the lumina of the thyroid follicles toweards the close of the experiment. Parathyroid chief cells showed hypertrophy from 21 to 35 days of the treatment. From day 28 to the close of the experiment they released their secretory product. After 42 days of experimental treatment a growth-promoting effect of calcitonin was observed (increase in body weight and femur weight. 相似文献
83.
In this paper a method to determine the appropriateness of energy resources in rural applications is discussed. Feasible energy
resources are comparatively evaluated using eight attributes representing the criteria of appropriateness. ‘Appropriateness’
is defined as a linear combination of attribute weights multiplied by attribute attainment levels which have been mapped into
utility for decision-makers. The uncertainty in data is handled using Monte-Carlo techniques. Sample results indicate a set
of dominant energy resources for a particular task. This method can be applied in real-life decision making concerning energy
resources for rural applications. 相似文献
84.
85.
Kathiravan Krishnamurthy Jagdish C. Tewari Joseph Irudayaraj Ali Demirci 《Food and Bioprocess Technology》2010,3(1):93-104
Pulsed UV light and infrared heat-treated Staphylococcus aureus cells were analyzed using transmission electron microscopy to identify the cell damage due to the treatment process. A 5-s
treatment with pulsed UV light resulted in complete inactivation of S. aureus even after enrichment. The temperature increase during the pulsed UV light treatment was insignificant, which suggested a
nonthermal treatment. S. aureus was also infrared heat treated using an infrared heating system with six infrared lamps. Five milliliters of S. aureus cells in phosphate buffer was treated at 700°C lamp temperature for 20 min. The microscopic observation clearly indicated
that there was cell wall damage, cytoplasmic membrane shrinkage, cellular content leakage, and mesosome disintegration after
both pulsed UV light and infrared treatments. Fourier transform infrared microspectrometry was successfully used to classify
the pulsed UV light and infrared heat-treated S. aureus by discriminant analysis. 相似文献
86.
Swapan K. Das Mahasweta Nandi Saurav Giri Asim Bhaumik 《Microporous and mesoporous materials》2009,117(1-2):362-367
A new mesoporous iron(III) borate material has been synthesized hydrothermally by using supramolecular assembly of cationic (cetyltrimethylammonium bromide, CTAB) or anionic (sodiumdodecyl sulfate, SDS) surfactant as structure directing agent (SDA) during co-condensation of Fe(III) and H3BO3 under controlled pH condition. Powder X-ray diffraction, N2 sorption, HRTEM, FE-SEM-EDS, AAS, FT-IR and UV–Vis spectroscopic tools, Mössbauer and magnetization measurements are used to characterize the nanostructure, porosity, morphology, chemical composition and magnetic properties. Template molecules can be removed from the as-synthesized material by two consecutive HCl–EtOH extraction and the template-free sample showed good surface area with a peak pore width of ca. 2.6 nm. Spectroscopic results suggested the octahedral coordination of Fe(III) in the FeBO3 framework. Magnetic measurements suggested the coexistence of antiferromagnetic core and the glassy magnetic behavior. The glassy magnetic behavior is ascribed to the dominant surface magnetism for mesoporous FeBO3. Acid catalytic properties of this material in liquid phase benzylation of mesityline and anisole have been studied. 相似文献
87.
88.
Muhammad Ahmad Asim Ali Khan Muhammad Amin Hafiz M. Asif Sobia Baig 《International Journal of Communication Systems》2019,32(14)
Quadrifilar helix antenna (QHA) has its applications in satellite communications. This paper presents the performance optimisation of input and radiation characteristics of QHA in the presence of infinite and finite metallic ground planes. For the infinite ground plane, it has been observed that input parameters such as impedance and voltage standing wave ratio (VSWR) are stable, and the antenna has broader half power beamwidth (HPBW). Smaller metallic platforms that act as finite ground planes produce better 3‐dB axial ratio beamwidth and boresight axial ratio. Deployment of QHA on smaller metallic platforms such as nanosatellites and CubeSats enhances the circularly polarised beamwidth of the antenna with improved boresight axial ratio. However, on large low earth orbit (LEO) satellites, stable input characteristics and broader HPBW have been achieved at the cost of narrow circularly polarised beamwidth and degraded boresight axial ratio. 相似文献
89.
Muhammad Farooq Muhammad Asim Muhammad Imran Shahid Imran Jameel Ahmad Muhammad Rizwan Younis 《Scientometrics》2018,117(3):1733-1753
This work describes the contribution of researchers in the field of the energy from Pakistan in the period 1990–2016. A scientometric approach was applied to analyze the scientific publications in the field using the Scopus Elsevier database. Different aspects of the publications were analyzed, such as publication type, major research areas, journals, citations, authorship pattern, affiliations as well as the keyword occurrence frequency. The present research trends are analyzed and future research directions are outlined. The impact factor, h-index and number of citations were used to investigate the strength of active institutes, authors, and journals in the field of the energy in Pakistan. From 1990 to 2016, 991 articles have been published by 2139 authors from 213 research institutes. The total number of citations and impact factor are 10,287 and 2301 respectively, corresponding to 10 citations per paper and an impact factor of 2.32 per publication. The research articles originate primarily from COMSATS, NUST, PIEAS, and PINSTECH. Pakistan has published 60% of publication with the collaboration of the foreign institutes, mainly from the United States, the United Kingdom, China and Malaysia. The core research activities in the field are mainly focused on resource assessment, energy policy, energy efficiency, feasibility study, energy economics, and performance assessment. The most productive journal, author, institution, are renewable & sustainable energy review, Shahbaz M., and COMSATS, respectively. 相似文献
90.
Standard potentials of Eθ of the silver-silver iodide electrode in ethanol + water and propan-2-ol + water mixtures have been determined from the emf of the cell Pt, H2 (g, 1 atm)|HI(itm), solvent| Agl-Ag at seven temperatures ranging from 10 to 40° for ethanol and from 5 to 35° for propan-2-ol. Free energies ΔSgqitt of transfer HI obtained therefrom have been briefly discussed in the light of ion-solvent interactions and solvent structure. 相似文献