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1.
Pradhan Umesh Kumar Ram Anirudh Sahu Balaram P. B. Udayakrishnan Lonkar Saurabh Kumbhar Laxmankumar 《Environmental science and pollution research international》2021,28(36):49725-49742
Environmental Science and Pollution Research - Nutrient source and transport study in tropical creeks adjacent to megacities are sparse on a regional and global scale. High-frequency chemical data... 相似文献
2.
Gunawan Juniati Permatasari Paulina Sharma Umesh 《Environment, Development and Sustainability》2022,24(9):11153-11194
Environment, Development and Sustainability - This study examines the sustainability and green banking performance of Indonesian banking sectors from their disclosures in sustainability reports... 相似文献
3.
Chandane Pradnya Jori Chandrashekhar Chaudhari Harshala Bhapkar Sunil Deshmukh Shubham Jadhav Umesh 《Environmental science and pollution research international》2020,27(6):5797-5808
Environmental Science and Pollution Research - The present study described a process for copper (Cu) bioleaching from waste printed circuit boards (PCBs). The 45 (±?0.18) mg/g Cu was... 相似文献
4.
Manish?PandeyEmail author P.?K.?Sharma Z.?Ahmad Umesh?Kumar?Singh 《Environmental Fluid Mechanics》2017,17(5):981-995
Scour is defined as the processes of removal of sediment particles from water stream bed by the erosive action of activated water, and also carries sediment away from the hydraulic structures. Scour is the main cause of pier failure. Numerous equations are available for estimating temporal and equilibrium scour depth. The present study describes the phenomenon of temporal scour depth variation at bridge piers and deals with the methods for its estimation. The accuracy of six temporal scour depth equations are also checked in this study. After graphical and statistical analysis, it was found that the relationship proposed by Oliveto and Hager (J Hydraul Eng (ASCE) 128(9):811–520, 2002) predicts temporal scour depth better than other equations. Three equations of equilibrium time of scour are also used for computing equilibrium time. Equilibrium time equation proposed by Choi and Choi (Water Environ J 30(1–2):14–21, 2016) gives better agreements with observed values. 相似文献
5.
Chetan M. Zade Umesh D. Pete Smita S. Patil Jitendra D. Bhosale Chakradhar D. Hadole Meghraj S. Kadam 《Journal of environmental science and health. Part. B》2013,48(2):136-143
Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by 1H and 13C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators. 相似文献
6.
Perrier F Richon P Gautam U Tiwari DR Shrestha P Sapkota SN 《Journal of environmental radioactivity》2007,97(2-3):220-235
The concentration activity of radon-222 has been monitored, with some interruptions, from 1997 to 2005 in the end section of a slightly rising, dead-end, 38-m long tunnel located in the Phulchoki hill, near Kathmandu, Nepal. While a high concentration varying from 6 x 10(3) Bq m(-3) to 10 x 10(3) Bq m(-3) is observed from May to September (rainy summer season), the concentration remains at a low level of about 200 Bq m(-3) from October to March (dry winter season). This reduction of radon concentration is associated with natural ventilation of the tunnel, which, contrary to expectations for a rising tunnel, takes place mainly from October to March when the outside air temperature drops below the average tunnel temperature. This interpretation is supported by temperature measurements in the atmosphere of the tunnel, a few meters away from the entrance. The temporal variations of the diurnal amplitude of this temperature indeed follow the ventilation rate deduced from the radon measurements. In the absence of significant ventilation (summer season), the radon exhalation flux at the rock surface into the tunnel atmosphere can be inferred; it exhibits a yearly variation with additional transient reductions associated with heavy rainfall, likely to be due to water infiltration. No effect of atmospheric pressure variations on the radon concentration is observed in this tunnel. This experiment illustrates how small differences in the location and geometry of a tunnel can lead to vastly different behaviours of the radon concentration versus time. This observation has consequences for the estimation of the dose rate and the practicability of radon monitoring for tectonic purposes in underground environments. 相似文献
7.
Research to alter crops for their better performance involving modern technology is underway in numerous plants, and achievements
in transgenic plants are impacting crop improvements in unparalleled ways. Striking progress has been made using genetic engineering
technology over the past two decades in manipulating genes from diverse and exotic sources, and inserting them into crop plants
for inducing desirable characteristics. RNA interference (RNAi) has recently been identified as a natural mechanism for regulation
of gene expression in all higher organisms from plants to humans and promises greater accuracy and precision to plant improvement.
The expression of any gene can be down-regulated in a highly explicit manner exclusive of affecting the expression of any
other gene by using RNAi technologies. Additional research in this field has been focused on a number of other areas including
microRNAs, hairpin RNA, and promoter methylation. Manipulating new RNAi pathways, which generate small RNA molecules to amend
gene expression in crops, can produce new quality traits and having better potentiality of protection against abiotic and
biotic stresses. Nutritional improvement, change in morphology, or enhanced secondary metabolite synthesis are some of the
other advantages of RNAi technology. In addition to its roles in regulating gene expression, RNAi is also used as a natural
defense mechanism against molecular parasites such as jumping genes and viral genetic elements that affect genome stability.
Even though much advancement has been made on the field of RNAi over the preceding few years, the full prospective of RNAi
for crop improvement remains to be fully realized. The intricacy of RNAi pathway, the molecular machineries, and how it relates
to plant development are still to be explained. 相似文献
8.
Fluoride contamination in the groundwater has got great attention in last few decades due to their toxicity, persistent capacity and accumulation in human bodies. There are several sources of fluoride in the environment and different pathways to enter in the drinking water resources, which is responsible for potential effect on human health. Presence of high concentration of fluoride ion in groundwater is a major issue and it makes the water unsuitable for drinking purpose. Availability of fluoride in groundwater indicates various geochemical processes and subsurface contamination of a particular area. Fluoride-bearing aquifers, geological factors, rate of weathering, ion-exchange reaction, residence time and leaching of subsurface contaminants are major responsible factors for availability of fluoride in groundwater. In India, several studies have reported that the groundwater of several states are contaminated with high fluoride. The undesirable level of fluoride in groundwater is one of the most natural groundwater quality problem, which affects large portion of arid and semiarid regions of India. Rajasthan, Andhra Pradesh, Telangana, Tamil Nadu, Gujarat, and West Bengal are the relatively high-fluoride-contaminated states in India. Chronic ingestion of high doses of fluoride-rich water leads to fluorosis on human and animal. Over 66 million Indian populations are at risk due to excess fluoride-contaminated water. Therefore, groundwater contamination subject to undesirable level of fluoride needs urgent attention to understand the role of geochemistry, hydrogeology and climatic factors along with anthropogenic inputs in fluoride pollution. 相似文献
9.
Soumen Maji Debasish Pal Prashanth R. Hanmaiahgari Umesh P. Gupta 《Environmental Fluid Mechanics》2017,17(4):853-877
This present study reports the results of an experimental study characterizing thorough variation of turbulent hydrodynamics and flow distribution in emergent and sparsely vegetated open channel flow. An emergent and rigid sparse vegetation patch with regular spacing between stems along the flow and transverse directions was fixed in the central region of the cross-section of open channel. Experiments were conducted in subcritical flow conditions and velocity measurements were obtained with an acoustic Doppler Velocimetry system. Large variations of the turbulence intensities, Reynolds shear stress, turbulent kinetic energy and vortical motions are found in and around the vegetation patch. At any cross-section through the interior of the vegetation patch, streamwise velocity decreases with increase in streamwise length and the velocity profiles converge from the log-law to a linear profile with increasing slope. Time-averaged lateral and vertical velocities inside the vegetation patch increase with increasing streamwise distance and converge from negative values to positive values. Turbulence intensities interior of the sparse vegetation patch are more than those of without the vegetation patch. Similar to the trend of streamwise velocity profiles inside the vegetation, turbulence intensities and longitudinal-normal Reynolds shear stress profile decreases with streamwise direction. In the interior of the vegetation patch and downstream of the trailing edge, turbulent kinetic energy profiles are exhibiting irregular fluctuations and the maximum values are occurring in the outer layer. Analysis of flow distribution confirms sparse vegetation patch is inducing a serpentine flow pattern in its vicinity. At the leading edge, flow is rushing towards the right hand sidewall, and at the trailing edge, flow is turning to the left hand sidewall. In between the leading and trailing edges, the streamlines are following a zig-zag fashion at varied degree along the streamwise and lateral directions. Immediate upstream of the leading edge and in the interior of the vegetation patch, vortex motion is clearly visible and the vortices are stretched along the width of the channel with streamwise direction. 相似文献
10.
Naik UC Srivastava S Thakur IS 《Environmental science and pollution research international》2011,19(7):3005-3014