Effect of addition of municipal solid waste compost (MSWC) on two metals viz. copper (Cu) and zinc (Zn) contents of submerged
rice paddies were studied. Experiments were conducted during the three consecutive wet seasons from 1997 to 1999 on rice grown
under submergence, at the Experimental Farm of Calcutta University, India. A sequential extraction method was used to determine
the metal (Cu and Zn) fractions in MSWC and cow dung manure (CDM). Both metals were significantly bound to the organic matter
and Fe and Mn oxides in MSWC and CDM. Metal content in rice straw was higher than in rice grain. Metal bound with Fe and Mn
oxides in MSWC and CDM best correlated with straw and grain metal followed by exchangeable and water soluble fractions. Carbonate,
organic matter bound and residual fractions in MSWC and CDM did not significantly correlate with rice straw and grain metal.
The MSWC would be a valuable resource for agriculture if it can be used safely, but long-term field experiments with MSWC
are needed to assess by regular monitoring of the metal loads and accumulation in soil and plants. 相似文献
As a catchment phenomenon, land use and land cover change (LULCC) has a great role in influencing the hydrological cycle. In this study, decadal LULC maps of 1985, 1995, 2005 and predicted-2025 of the Subarnarekha, Brahmani, Baitarani, Mahanadi and Nagavali River basins of eastern India were analyzed in the framework of the variable infiltration capacity (VIC) macro scale hydrologic model to estimate their relative consequences. The model simulation showed a decrease in ET with 0.0276% during 1985–1995, but a slight increase with 0.0097% during 1995–2005. Conversely, runoff and base flow showed an overall increasing trend with 0.0319 and 0.0041% respectively during 1985–1995. In response to the predicted LULC in 2025, the VIC model simulation estimated reduction of ET with 0.0851% with an increase of runoff by 0.051%. Among the vegetation parameters, leaf area index (LAI) emerged as the most sensitive one to alter the simulated water balance. LULC alterations via deforestation, urbanization, cropland expansions led to reduced canopy cover for interception and transpiration that in turn contributed to overall decrease in ET and increase in runoff and base flow. This study reiterates changes in the hydrology due to LULCC, thereby providing useful inputs for integrated water resources management in the principle of sustained ecology. 相似文献
The demand for coal from surface mining projects are on the higher side like never before for which blasting is the basic unit operation. The explosive plays an important role in blasting and also influence the explosive-rock interaction. The most common explosive type used in surface mines is emulsion explosives. This paper presents the study on the detonation velocity of bulk emulsion explosives due to variation in gassing agent and density. In this study Sodium Nitrite (NaNO2) has been used as the gas generating additive and the performance of emulsion explosives with different concentrations of gassing agents at different temperatures has been observed. This study was undertaken to also understand the cyclic variation of temperature on gassing kinetics and performance of explosive. The effect of cooling on detonic-behaviour of bulk emulsion explosives has also been studied and presented in this paper. 相似文献
We examine the management of livestock diseases from the producers‘ perspective, incorporating information and incentive asymmetries
between producers and regulators. Using a stochastic dynamic model, we examine responses to different policy options including
indemnity payments, subsidies to report at-risk animals, monitoring, and regulatory approaches to decreasing infection risks
when perverse incentives and multiple policies interact. This conceptual analysis illustrates the importance of designing
efficient combinations of regulatory and incentive-based policies.
Using intermediate degreep-mode frequency data sets for solar cycle 22, we find that the frequency shifts and magnetic activity indicators show a “hysteresis”
phenomenon. It is observed that the magnetic indices follow different paths for the ascending and descending phases of the
solar cycle while for radiative indices, the separation between the paths are well within the error limits. 相似文献
Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients
with solar cycle. Frequencies and even-order coefficients are found to change significantly with rising phase of the solar
cycle. We also find temporal variations in the rotation rate near the solar surface. 相似文献
Unstiffened steel plate shear walls (SPSWs) are used as lateral load‐resisting systems in building structures. The energy dissipation mechanism of SPSWs consists of the tension yielding of web plates and the formation of plastic hinges at the ends of horizontal boundary elements. However, vertical boundary elements (VBEs) of high‐rise SPSWs may experience high axial forces under lateral loading. This study explores the effectiveness of staggering of web plates on the reduction of VBE forces and drift response of SPSWs during an earthquake event. An analytical study has been conducted to determine the base shear reduction factor so as to match the overstrength of staggered systems with conventional SPSWs. A design methodology has been proposed for staggered SPSWs. Six‐, 9‐, and 20‐storey staggered and conventional SPSWs with varying aspect ratios are considered in this study to compare their seismic response. These study frames are modelled and analysed in OpenSEES platform. Nonlinear static and dynamic analyses are performed to compare the drift response, hinge mechanisms, and steel tonnage. Staggered SPSWs showed uniform drift distribution and reduction in interstorey drift and axial force demand on the VBEs. 相似文献
This study presents a nonlinear modelling technique for reinforced concrete (RC) frames retrofitted with metallic yielding devices to predict the seismic response using a computer software OpenSees. The numerical model considers the axial–flexure interaction, shear force–displacement response and the bond-slip characteristics of the frame members. The predicted hysteretic response has been compared with the results of slow-cyclic testing. The validated numerical model is then used to predict the seismic response of a five-story RC frame with soft-story. Nonlinear cyclic pushover and dynamic analyses are conducted to investigate the effectiveness of the proposed retrofitting scheme in enhancing the lateral strength and energy dissipation potential and in controlling the premature failure of the study frame. Analysis results showed significant improvement in the seismic response of RC frames with soft-story using the proposed retrofitting technique. 相似文献
Buckling-restrained braced frames (BRBFs) are vulnerable to relatively higher post-earthquake residual drifts under high intensity ground shakings. This is primarily due to the low axial elastic and post-elastic stiffness of buckling-restrained braces (BRBs) satisfying the design force demand requirements. In the present study, a hybrid buckling restrained bracing system consisting of a short yielding core length BRB component and a conventional buckling-type brace component connected in series has been developed with an aim to increase the axial stiffness of braces. This study is focused on the experimental investigation of six hybrid bucking restrained braces (HBRBs) to investigate their overall behavior, load-resisting capacity, strength-adjustment factors and energy dissipation potential. The main parameters varied are the cross-sectional area, the yielding length of core elements as well as the detailing of buckling-restraining system of short yielding core length BRBs. Test results showed that the HBRBs with yielding core length in the range of 30% of work-point to work-point lengths withstood an axial strain of 6% without any instability and can deliver stable and balanced hysteretic response and excellent energy dissipation under reversed cyclic loading conditions.