8,815 research outputs found
Gender in lift irrigation schemes in East Gujarat, India
Irrigation management / Participatory management / Women in development / Woman's status / Gender / Irrigated farming / Irrigation programs / Water lifting / Communal irrigation systems / Cooperatives / Legal aspects / Decision making / Villages
Hot Spots on the Fermi Surface of Bi2212: Stripes versus Superstructure
In a recent paper Saini et al. have reported evidence for a pseudogap around
(pi,0) at room temperature in the optimally doped superconductor Bi2212. This
result is in contradiction with previous ARPES measurements. Furthermore they
observed at certain points on the Fermi surface hot spots of high spectral
intensity which they relate to the existence of stripes in the CuO planes. They
also claim to have identified a new electronic band along Gamma-M1 whose one
dimensional character provides further evidence for stripes. We demonstrate in
this Comment that all the measured features can be simply understood by
correctly considering the superstructure (umklapp) and shadow bands which occur
in Bi2212.Comment: 1 page, revtex, 1 encapsulated postscript figure (color
Hierarchical approach to 'atomistic' 3-D MOSFET simulation
We present a hierarchical approach to the 'atomistic' simulation of aggressively scaled sub-0.1-μm MOSFETs. These devices are so small that their characteristics depend on the precise location of dopant atoms within them, not just on their average density. A full-scale three-dimensional drift-diffusion atomistic simulation approach is first described and used to verify more economical, but restricted, options. To reduce processor time and memory requirements at high drain voltage, we have developed a self-consistent option based on a solution of the current continuity equation restricted to a thin slab of the channel. This is coupled to the solution of the Poisson equation in the whole simulation domain in the Gummel iteration cycles. The accuracy of this approach is investigated in comparison to the full self-consistent solution. At low drain voltage, a single solution of the nonlinear Poisson equation is sufficient to extract the current with satisfactory accuracy. In this case, the current is calculated by solving the current continuity equation in a drift approximation only, also in a thin slab containing the MOSFET channel. The regions of applicability for the different components of this hierarchical approach are illustrated in example simulations covering the random dopant-induced threshold voltage fluctuations, threshold voltage lowering, threshold voltage asymmetry, and drain current fluctuations
Constraints on the Growth and Spin of the Supermassive Black Hole in M32 From High Cadence Visible Light Observations
We present 1-second cadence observations of M32 (NGC221) with the CHIMERA
instrument at the Hale 200-inch telescope of the Palomar Observatory. Using
field stars as a baseline for relative photometry, we are able to construct a
light curve of the nucleus in the g-prime and r-prime band with 1sigma=36
milli-mag photometric stability. We derive a temporal power spectrum for the
nucleus and find no evidence for a time-variable signal above the noise as
would be expected if the nuclear black hole were accreting gas. Thus, we are
unable to constrain the spin of the black hole although future work will use
this powerful instrument to target more actively accreting black holes. Given
the black hole mass of (2.5+/-0.5)*10^6 Msun inferred from stellar kinematics,
the absence of a contribution from a nuclear time-variable signal places an
upper limit on the accretion rate which is 4.6*10^{-8} of the Eddington rate, a
factor of two more stringent than past upper limits from HST. The low mass of
the black hole despite the high stellar density suggests that the gas liberated
by stellar interactions was primarily at early cosmic times when the low-mass
black hole had a small Eddington luminosity. This is at least partly driven by
a top-heavy stellar initial mass function at early cosmic times which is an
efficient producer of stellar mass black holes. The implication is that
supermassive black holes likely arise from seeds formed through the coalescence
of 3-100 Msun mass black holes that then accrete gas produced through stellar
interaction processes.Comment: 8 pages, 3 figures, submitted to the Astrophysical Journal, comments
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Simulation-based performance prediction of an energy-harvesting facade system with selective daylight transmission
Shading devices are effective in controlling glare and solar heat gains in buildings. However, this occurs at the expense of daylight and outside view. This paper evaluates the thermal and daylight performance of Lumiduct, a sun-controlling dynamic façade system that permits only diffuse radiation inside the building, while producing electricity. This imparts Lumiduct a unique characteristic of acting as a shading device while providing useful daylight and view to the outside. The first part of the paper briefly illustrates the working principle of Lumiduct and its functional characteristics and then, introduces the basic principles of the modelling and simulation strategy used to predict its performance. To demonstrate this strategy we use TypeDLT, a TRNSYS type that performs integrated thermal and daylight simulations by coupling TRNSYS’ multi-zone building model with Radiance’s three-phase method. This strategy relies on the use of customized and time-controlled bidirectional scattering distribution functions (BSDF) to characterize the separate treatment of direct and diffuse radiation and the sun-tracking behaviour of the façade. In the second part, we demonstrate the performance of Lumiduct in comparison to a high-performance window with and without a dynamic venetian blind system as a shading device for a typical office room for the climate of Amsterdam. The results show a significantly higher daylight utilization along with a reduction in energy use of the building
Orbital Degeneracy and Peierls Instability in Triangular Lattice Superconductor IrPtTe
We have studied electronic structure of triangular lattice
IrPtTe superconductor using photoemission spectroscopy and
model calculations. Ir core-level photoemission spectra show that Ir
charge modulation established in the low temperature phase of IrTe
is suppressed by Pt doping. This observation indicates that the suppression of
charge modulation is related to the emergence of superconductivity.
Valence-band photoemission spectra of IrTe suggest that the Ir charge
modulation is accompanied by Ir orbital reconstruction. Based on the
photoemission results and model calculations, we argue that the
orbitally-induced Peierls effect governs the charge and orbital instability in
the IrPtTe.Comment: 5 pages,4 figure
Induction of Mutation in Rough Lemon (Citrus jambhiri Lush.) Using Gamma Rays
The present investigation was carried out to study variability induced by gamma rays with respect to vegetative characters and LD50 dose in Rough lemon. Rough lemon seeds were gamma irradiated at doses of 0, 4, 6 and 8 kr along with control. Seed germination decreased with increasing dose of gamma radiation. Seedling height and leaf size also decreased with increasing dose of gamma radiation, whereas, apical branching, number of branches/seedling, number of variegated / albino seedlings and number of leaves increased with increasing dose of gamma radiation. Maximum variability for seedling height, number of leaves, leaf size, colour, internode length, and per cent apical branching was observed at two months from sowing in seeds treated with 8 kr dose of gamma radiation. Variability for all characters was, however, found to be minimum in the control
Effect of Ply Orientation on Strength and Failure Mode of Pin Jointed Unidirectional Glass-epoxy Nanoclay Laminates
In the present work the effect of the different ply orientations and nano filler on the bearing strength and failure mode of the pin joints is investigated both experimentally and numerically. Glass-epoxy composite laminates were prepared with [0°/45°/90°], [0°/45°/0°] and [0°/90°/0°] ply orientations. Nanoclay filler with 1, 2, 3, 4 and 5wt% were added in the epoxy for the said orientations to prepare the pin joints. Results show that the strength of the pin joints is drastically dependent on both ply orientations and nanofiller wt%. The joint geometry i.e., the distance from the free edge of specimen to the diameter of the hole (E/D) ratio and width of the specimen to the diameter of the holes (W/D) ratio were also investigated which effected the failure mode of the joints. Tsai-Wu failure theory along with the characteristics curve method was used for the prediction of failure modes numerically
Effect of Metallic Inserts on the Strength of Pin Joints Prepared from Glass Fiber Reinforced Composites
The present study deals with the failure analysis of pin joints by varying different geometric parameters i.e., edge distance to hole diameter (E/D) ratio and width to hole diameter (W/D) ratio. Pin joints were prepared from the glass fiber reinforced laminates incorporating the metal inserts. A range of 2 to 5 and 3 to 6 was considered for E/D and W/D ratios, respectively. The stress around the hole was redistributed by incorporating the metal inserts in the hole to increase the load carrying capacity. To predict the failure loads and failure modes numerically, progressive damage analysis along with Hashin failure criteria was used in the pin joints. Strength of the pin joints increased in the range of 65 per cent to 92 per cent with metal insert due to the redistribution of the stresses around the hole. Progressive damage analysis gave a good correlation with experimental findings. Thereafter, the strength of the joint was predicted by varying the thickness of the metal inserts
Identification of Microbial Population during Oil Palm Frond (OPF) Composting using Light and Scanning Electron Microscopy
This investigation highlights the activity and diversity of fungal population observed on oil palm fronds (OPF) during composting process employing Scanning Electron Microscope (SEM) and conventional identification methods. Composting is a controlled biological decomposition process, which converts organic wastes into humus-like material. It is a process that involves microbial degradation of complex organic materials under moist, self-heating and aerobic conditions; and characterized by a succession of various microbial populations. Two white rot fungi species were introduced as inoculant, namely Trametes versicolor and Schizophyllum commune. The main objective for inoculation was to shorten the composting period and produce high quality compost. In this study, the oil palm fronds (OPF) were composted for 14 weeks, with four treatment; i) control (untreated OPF), ii) OPF treated with T. versicolor, iii) OPF treated with S. commune, iv) OPF treated with both T. versicolor and S. commune, and four replicates for each. A total of eight genera of fungi namely Aspergillus, Trichoderma, Absidia, Geotrichum, Trametes, Schizophyllum, Syncephalastrum and Beauveria species were isolated and identified from composted OPF. Although T. versicolor and S. commune were introduced as accelerating agents, the presence of other fungal species perhaps occurred due to the indigenous microflora that already existed on OPF, leading to a succession of various fungi species based on the complexity of biological process in composting substrate. Keywords: Composting, oil palm frond, white-rot fungi, inoculants, Trametes versicolor, Schizophyllum commune ABSTRAKKajian ini menumpukan kepada aktiviti dan kepelbagaian populasi kulat yang terdapat pada pelepah sawit sepanjang tempoh pengkomposan, dengan menggunakan Mikroskop Elektron Pengimbas (SEM) dan teknik identifikasi konvensional. Pengkomposan merupakan proses penguraian biologi terkawal, yang menukarkan sisa organik kepada bahan-seperti-humus. Ia adalah suatu proses yang melibatkan penguraian mikrob terhadap bahan organik kompleks dalam keadaan lembap, pemanasan-diri dan aerobik; dan proses ini dicirikan oleh sesaran pelbagai jenis populasi mikrob. Dua spesies kulat pereput putih iaitu Trametes versicolor dan Schizophyllum commune telah diperkenalkan sebagai inokula dalam pengkomposan pelepah sawit. Objektif utama inokulasi adalah untuk memendekkan tempoh pengkomposan dan menghasilkan kompos berkualiti tinggi. Dalam kajian ini, pelepah sawit dikomposkan selama 14 minggu, dengan empat rawatan yang digunakan iaitu; i) kawalan (pelepah tidak dirawat), ii) pelepah dirawat dengan T. versicolor, iii) pelepah dirawat dengan S. commune, iv) pelepah dirawat dengan T. versicolor dan S. commune, dengan empat replikasi. Secara keseluruhannya, terdapat lapan genus kulat, iaitu Aspergillus, Trichoderma, Absidia, Geotrichum, Trametes, Schizophyllum, Syncephalastrum dan Beauveria telah diasingkan dan dikenalpasti dalam kompos pelepah sawit. Walaupun T. versicolor dan S. commune telah diperkenalkan sebagai agen pecutan, kehadiran pelbagai populasi kulat lain mungkin dipengaruhi oleh mikroflora semulajadi yang hadir dalam substrat pengkomposan, serta proses sesaran pelbagai spesies kulat yang bergantung kepada proses biologi kompleks yang berlaku dalam substrat pengkomposan. Kata kunci: Pengkomposan, pelepah sawit, kulat pereput putih, inokula, Trametes versicolor, Schizophyllum commun
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