Impact of plankton structure on primary productivity in two beels of West Bengal, India

Planktonic community in floodplain wetlands embodies the energy transfer through this phase and indicates trophic status of lake. Originally rich bottom coupled with a conducive physicochemical environment encourages fast colonization of the plankton population. Present investigation was carried out in two floodplain wetlands having characteristics of open (Amda beel) and closed (Suguna beel) system. The physicochemical parameters of water and soil of the investigated heels were by and large conducive for planktonic growth. The density of plankton population varied between 1,346 and 2,170 u/l in Suguna bed whereas in Amda beel it ranged from 1,030 to 1,802 u/l. Seasonal fluctuations in water column were conspicuous and mostly dependent on the replenished resources and volume, A mixed and balanced population of diversified fauna constituted the plankton population of the investigated ecosystems. Mostly the diversity was observed to be maximum during winter seasons with coincidence of favorable temperature, dissolved oxygen and other physico-chemical parameters of water besides optimum solar penetration. Richness of planktonic structure in closed system (Suguna) resulted in higher fish production (1,570,05 kg/ha/yr) than that of open system (Amda) (384.4 kg/ha/yr)

A new algorithm for continuous-discrete filtering with randomly delayed measurements

This paper is a postprint of a paper submitted to and accepted for publication in IET Control Theory & Applications and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library.The filtering of nonlinear continuous-discrete systems is widely applicable in real-life and extensive literature is available to deal with such problems. However, all of these approaches are constrained with the assumption that the current measurement is available at every time step, although delay in measurement is natural in real-life applications. To deal with this problem, we re-derive the conventional Bayesian approximation framework for solving the continuous-discrete filtering problems. In practice, the delay is often smaller than one sampling time, which is the main case considered here. During the filtering of such systems, the actual time of correspondence should be known for a measurement received at the kth time instant. In this paper, a simple and intuitively justified cost function is used to decide the time to which the measurement at kth time instant actually corresponds. The performance of the proposed filter is compared with a conventional filter based on numerical integration which ignores random delays for a continuousdiscrete tracking problem. We show that the conventional filter fails to track the target while the modification proposed in this paper successfully deals with random delays. The proposed method may be seen as a valuable addition to the tools available for continuous-discrete filtering in nonlinear systems

Active flutter suppression of a cantilever plate at supersonic speeds

Modern high-speed aircrafts are flown using the fly-by- wire system. The d y n a m i c s of automatic flight control system interacts with aircraft's structural dynamics and aerodynamics to give rise to aero servo elastic problems. Such problems can be avoided using an active control system. AS a feasibility study, active flutter suppression of a cantilever plate wing was carried out. In this study it was demonstrated that the flutter Mach number of the cantilever wing can be increased by 12.5%

Some socio-economic aspects of the fishermen of twin pronged floodplain wetlands in West Bengal

A socio-economic investigation was carried out in two fishermen cooperative societies namely Purba Helatala Fishermen Co-operative Society (E-1), Barhal Fishermen Co-operative Society (E-2), under Maldah district, West Bengal to which the beels (flood plains) under study belong. A total of 132 member fishermen, which constituted the sample, were personally interviewed. The age group of the fishermen of the sample in E-1 varied between 20 and 66 years whereas in E-2 it was 22 and 61 years. All the members of the sample belonged to Scheduled Caste (SC) community. The primary occupation of all the respondents of both the beels was observed to be fishing (100%). Maximum number of illiterate respondents was observed to 56% in E-2 and 35% in E-1. It has been observed that as many as 38.3% of fishermen were having fishing experience which ranging from 16 to 20 years in E-1 whereas it was 6 - 10 years (36.1%) in E-2. Maximum number of fishermen lived in thatched houses (41.66%) in E-1 whereas in E-2 most of them lived in houses made of corrugated tin/tile shed (41.66%). As many as 41.55% of E-1 and 30.55% of E-2 used dug-out canoes for their fishing. Maximum number of fishermen used cast net with individualistic approach (100%) followed by Gill net (E-1:41.56% and E-2:55.55%). Most of the fishermen of the sample participated in fishing activities for 241 to 270 days (41.66%) in E-2 whereas it was 211 to 240 days (33.33 %) in E-1 in a year. During fishing season as many as 40.0% of the respondents of E-1 earned on an average Rs. 801.00 to Rs. 900.00 per month whereas it was Rs. 901.00 to Rs.1,000.00 (43.05%) in case of E-2. A section of fishermen of the sample borrowed money often (51.6%) E-1 whereas it was most often (27.27%) of E-2. The respondents of E-2 made regular repayment of the loan to the maximum extent (79.48%) whereas it was 57.44% in E-1. Higher fish production vis-a-vis higher income for the fishermen was observed in the beel (E2) having close characteristic

Purification and properties of an endoglucanase from Thermoascus aurantiacus

AbstractAn Endo-cellulase was purified to homogeneity using ammonium sulfate precipitation, ion exchange and size exclusion chromatography from newly isolated strain of Thermoascus aurantiacus RBB-1. The recovery and purification fold were 13.3% and 6.6, respectively, after size exclusion chromatography. The purified cellulase has a molecular mass (M) of 35kDa. Optimum temperature for the enzyme was found to be 70°C and stability was upto 80°C for 1h. Along with higher stability at 80°C, enzyme showed half lives of 192h and 144h at 50 and 70°C respectively. The purified cellulase was optimally active at pH 4.0 and was stable over a broad pH range of 3.0–7.0. The enzyme purified showed apparent Km and Vmax values of 37mg/ml and 82.6U/min/mg protein respectively with higher salt tolerance of 10% for 1h

Linear Spatial Stability Analysis of Mixed Convection Boundary Layer over a Heated Plate

The spatial stability properties of a mixed convection boundary layer developed over a heated horizontal flat plate is investigated under the linear and quasi-parallel assumptions by solving the Orr-Sommerfeld equations. The main aim of this work is to find a critical buoyancy parameter above which a qualitative change in the stability characteristics of the mixed convection boundary layer due to the influence of heat transfer is displayed. The equilibrium flow used here is that given by the similarity solution of [1] which implies the wall temperature to vary as the inverse square root of the distance from the leading edge of the plate. The Orr-Sommerfeld equation has been solved by using the compound matrix method (CMM)-- which locates all the modes in a chosen range of complex wave number, for spatial stability analysis. Cases with different buoyancy parameters have been investigated which were earlier reported incorrectly in [2]. Results indicate modifications of the hydrodynamic mode with certain buoyancy parameter for which continuous existence of instability as the flow develops downstream. The erroneous results in the above mentioned paper is associated with the wrong choice of compound variables used in CMM and the associated dispersion relation satisfied at the wall. Key Words: Mixed Convection Flow; Orr-Sommerfeld Equation; Spatial Stability Analysis; Compound Matrix Method (CMM

Quenched growth of nanostructured lead thin films on insulating substrates

Lead island films were obtained via vacuum vapor deposition on glass and ceramic substrates at 80 K. Electrical conductance was measured during vapor condensation and further annealing of the film up to room temperature. The resistance behavior during film formation and atomic force microscopy of annealed films were used as information sources about their structure. A model for the quenched growth, based on ballistic aggregation theory, was proposed. The nanostructure, responsible for chemiresistive properties of thin lead films and the mechanism of sensor response are discussed.Comment: 2 figures; accepted to Thin Solid Film

Collinear N\'eel-type ordering in partially frustrated lattices

We consider two partially frustrated S = 1/2 antiferromagnetic spin systems on the triangular and pentagonal lattices. In an elementary plaquette of the two lattices, one bond has exchange interaction strength $\alpha$ ($\alpha \leq 1$) whereas all other bonds have exchange interaction strength unity. We show that for $\alpha$ less than a critical value $\alpha_{c}$, collinear N\'eel-type ordering is possible in the ground state. The ground state energy and the excitation spectrum have been determined using linear spin wave theory based on the Holstein-Primakoff transformation.Comment: Four pages, LaTeX, Four postscripts figures, Phys. Rev. B58, 73 (1998

The State-Vector Space for Two-Mode Parabosons and Charged Parabose Coherent States

The structure of the state-vector space for the two-mode parabose system is investigated and a complete set of state-vectors is constructed. The basis vectors are orthonormal in order $p=2$. In order $p=2$, conserved-charge parabose coherent states are constructed and an explicit completeness relation is obtained.Comment: 13 pages, LaTeX file, no figures and no macro

A magnetically recoverable nanocatalyst based on functionalized mesoporous silica

Nylon bags are used for packaging fire debris in several countries, particularly in Europe. The possibility of cross-contamination during transport from the fire scene to the laboratory, in normal casework conditions in the UK, was studied for two brands of nylon bags, using simulated heavy loaded fire debris. Three experiments were carried out with each brand, using as sample a piece of cotton fabric soaked with gasoline. One experiment was carried out using automotive paint thinner (oxygenated solvent). Each sample was sealed in a nylon bag and stored in contact with eight empty bags. The empty bags were analysed at regular intervals for a period of time up to eight weeks, using SPME and GC/MS. Cross-contamination was found for components of gasoline (toluene and C2-alkylbenzenes) in the two brands of nylon bags used, after 4 days and 2 weeks. Cross-contamination using automotive topcoat thinner was detected after 2 days