6,640 research outputs found
Growth of Certain Tree Species in Fly Ash Amended Soil
The study reports on the use of fly ash on the growth of five tree species namely Subabul (Leucaena leucocephala), Chakundi (Cassia siamea) Black sins (Albizia lebbek), Shisham (Dalbergia sissoo) and Gamhar (Gmelina arborea). Out off ivespecies, theformerfourare nitrogenfixers belonging to thefarnilyLeguminsae and the last one viz. Gamhar is an excellent fast growing timber tree species
belonging to thefamily Verbenaceae. The experiment was conducted in cement pots for one year (August 1993 to August 1994) in completely randomised design (CRD)
with five treatments and four replications to record the growth parameters viz. collar diameter, height, number of leaves and leaf area at 30 days interval. The five treatments were : T (No fly ash, only 20 kg soil), Tl (Soil + 5% Fly ash), T2 (Soil + 10%fy ash), T3 (Soil + 20% f 1y ash) and T, (Soil + 50% fly ash). Results reveal that
collar diameter, height, number of leaves and leaf area of all the five tree species increased progressively up to 20% Fly ash addition to acid soils of Chotanagpur region. It was also observed that 50%f ly ash addition on soil was superior to control (no fly ash, only soil) in respect of all growth parameters except number of leaves and leaf area ofBlack sins, Subabul and Gamhar, and collar diameter of Chakundi and Gamhar. In general, fly ash addition to soil had a beneficial impact on the growth of the above mentioned tree species. These tree species are recommended
for afforestation and reforestation of waste lands at 20% fly ash (w/w) levels
Towards the Formal Reliability Analysis of Oil and Gas Pipelines
It is customary to assess the reliability of underground oil and gas
pipelines in the presence of excessive loading and corrosion effects to ensure
a leak-free transport of hazardous materials. The main idea behind this
reliability analysis is to model the given pipeline system as a Reliability
Block Diagram (RBD) of segments such that the reliability of an individual
pipeline segment can be represented by a random variable. Traditionally,
computer simulation is used to perform this reliability analysis but it
provides approximate results and requires an enormous amount of CPU time for
attaining reasonable estimates. Due to its approximate nature, simulation is
not very suitable for analyzing safety-critical systems like oil and gas
pipelines, where even minor analysis flaws may result in catastrophic
consequences. As an accurate alternative, we propose to use a
higher-order-logic theorem prover (HOL) for the reliability analysis of
pipelines. As a first step towards this idea, this paper provides a
higher-order-logic formalization of reliability and the series RBD using the
HOL theorem prover. For illustration, we present the formal analysis of a
simple pipeline that can be modeled as a series RBD of segments with
exponentially distributed failure times.Comment: 15 page
Coupling and tuning of modal frequencies in direct current biased microelectromechanical systems arrays
Understanding the coupling of different modal frequencies and their tuning mechanisms has become essential to design multi-frequency MEMS devices. In this work, we fabricate a MEMS beam with fixed boundaries separated from two side electrodes and a bottom electrode. Subsequently, we perform experiments to obtain the frequency variation of in-plane and out-of-plane mechanical modes of the microbeam with respect to both DC bias and laser heating. We show that the frequencies of the two modes coincide at a certain DC bias, which in turn can also be varied due to temperature. Subsequently, we develop a theoretical model to predict the variation of the two modes and their coupling due to a variable gap between the microbeam and electrodes, initial tension, and fringing field coefficients. Finally, we discuss the influence of frequency tuning parameters in arrays of 3, 33, and 40 microbeams, respectively. It is also found that the frequency bandwidth of a microbeam array can be increased to as high as 25 kHz for a 40 microbeam array with a DC bias of 80 V
Implementation of the CRPA model in the GENIE event generator and analysis of nuclear effects in low-energy transfer neutrino-nucleus interactions
We present the implementation and validation of the Hartree-Fock continuum
random phase approximation (HF-CRPA) model in the GENIE neutrino-nucleus
interaction event generator and a comparison of the subsequent predictions to
experimental measurements of lepton kinematics from interactions with no mesons
in the final state. These predictions are also compared to those of other
models available in GENIE. It is shown that, with respect to these models,
HF-CRPA predicts a significantly different evolution of the cross section when
moving between different interaction targets, when considering incoming
anti-neutrinos compared to neutrinos and when changing neutrino energies. These
differences are most apparent for interactions with low energy and momentum
transfer. It is also clear that the impact of nucleon correlations within the
HF-CRPA framework is very different than in GENIE's standard implementation of
RPA corrections. Since many neutrino oscillation experiments rely on their
input model to extrapolate between targets, flavours, and neutrino energies,
the newly implemented HF-CRPA model provides a useful means to verify that such
differences between models are appropriately covered in oscillation analysis
systematic error budgets.Comment: 13 pages, 12 figures. Significant update from previous versio
The spectral form factor is not self-averaging
The spectral form factor, k(t), is the Fourier transform of the two level
correlation function C(x), which is the averaged probability for finding two
energy levels spaced x mean level spacings apart. The average is over a piece
of the spectrum of width W in the neighborhood of energy E0. An additional
ensemble average is traditionally carried out, as in random matrix theory.
Recently a theoretical calculation of k(t) for a single system, with an energy
average only, found interesting nonuniversal semiclassical effects at times t
approximately unity in units of {Planck's constant) /(mean level spacing). This
is of great interest if k(t) is self-averaging, i.e, if the properties of a
typical member of the ensemble are the same as the ensemble average properties.
We here argue that this is not always the case, and that for many important
systems an ensemble average is essential to see detailed properties of k(t). In
other systems, notably the Riemann zeta function, it is likely possible to see
the properties by an analysis of the spectrum.Comment: 4 pages, RevTex, no figures, submitted to Phys. Rev. Lett., permanent
e-mail address, [email protected]
Utilization of lignocellulosic waste for ethanol production: Enzymatic digestibility and fermentation of pretreated shea tree sawdust
Enzymatic hydrolysis and fermentation methods were evaluated on alkaline peroxide pretreated shea tree
sawdust conversion to ethanol. Optimum pretreatment conditions of 120 oC reaction temperature, 30 min reaction time,
and 20 mL L−1 of water hydrogen peroxide concentration (1%(v/v)H2O2) solubilized 679 g kg−1 of hemicellulose and
172 g kg−1 of lignin. 617 g kg−1 cellulose was retained in the solid fraction. The maximum yield of reducing sugar with
optimized enzyme loadings by two enzyme preparations (cellulase and β-glucosidase) was 165 g kg−1 of dry biomass.
The ethanol yield was 7.35 g L−1 after 72 h incubation period under the following conditions: 2% cellulose loading,
enzyme concentration was 25 FPU (g cellulose)−1 loading, yeast inoculums was 10% (v/v), 32 oC, and pH 4.8. The
pretreatments gave information about the hindrances caused by lignin presence in lignocellulosic materials and that
hemicelluloses are better hydrolyzed than lignin, thereby enhancing enzymatic digestibility of the sawdust materia
Parity Effects in Eigenvalue Correlators, Parametric and Crossover Correlators in Random Matrix Models: Application to Mesoscopic systems
This paper summarizes some work I've been doing on eigenvalue correlators of
Random Matrix Models which show some interesting behaviour. First we consider
matrix models with gaps in there spectrum or density of eigenvalues. The
density-density correlators of these models depend on whether N, where N is the
size of the matrix, takes even or odd values. The fact that this dependence
persists in the large N thermodynamic limit is an unusual property and may have
consequences in the study of one electron effects in mesoscopic systems.
Secondly, we study the parametric and cross correlators of the Harish
Chandra-Itzykson-Zuber matrix model. The analytic expressions determine how the
correlators change as a parameter (e.g. the strength of a perturbation in the
hamiltonian of the chaotic system or external magnetic field on a sample of
material) is varied. The results are relevant for the conductance fluctuations
in disordered mesoscopic systems.Comment: 12 pages, Latex, 2 Figure
Non-destructive Quality Monitoring of Fresh Fruits and Vegetables
Quality determines the shelf life as well as selling price of fresh fruit or vegetable and therefore, quality monitoring and testing of fresh commodities have paramount importance in their postharvest handling and supply chain management. Most of the methods used to assess fruits and vegetables quality are destructive in nature. Now-a-days, various mechanical, optical, electromagnetic, and dynamic non-destructive methods are gaining importance due to ease in operations, faster turn over and reliability. Some of the non-destructive techniques (NDT) are currently being used in laboratories, research institutions and food packaging and processing industries, whereas, some methods are still at developmental stage. Various NDT with respect to their principle and applications such as impact test, electronic nose, time-resolved reflectance spectrometry (TSR), near infrared spectroscopy (NIR), nuclear magnetic resonance (NMR), X-Ray, ultra sonic, acoustic impulse response method, electrical conductivity methods etc., are discussed in this review
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