Studies on Tolerance Level Against Antheraea mylitta Cytoplasmic Polyhedrosis Virus (AmCPV) in Different Eco-races of Tropical Tasar Silkworm, Antheraea Mylitta Drury

( G. P. Singh ),( S. B. Zeya ),( A. K. Srivastava ),( N. G. Ojha ),( N. Suryanarayana ) 한국잠사학회 2008 International Journal of Industrial Entomology Vol.17 No.1

Pathogenic infection in tasar silkworm, Antheraea mylitta Drury is common and there is a breed specific response regarding tolerance. Hence, the tolerance level of three eco-races of tasar silkworm viz. Daba, Sarihan and Raily to Antheraea mylitta cytoplasmic polyhedrosis virus (AmCPV) infection was tested. The survival of Daba, Sarihan and Raily eco-races was significantly different (p<0.05) when challenged with the same concentration (1 x 10(5) polyhedra/ml) of AmCPV. Daba eco-race was more tolerant to the AmCPV infection having higher survival (65.7%) and LC50 values (1000893.17 polyhedra/ml) of AmCPV followed by Sarihan eco-race (50.7% survival and LC50 value of AmCPV 187203.6168 polyhedra/ml) and Raily ecorace (24.3% survival and LC50 value of AmCPV 5176.37 polyhedra/ml). The tolerance level of Daba and Sarihan eco-races against AmCPV was more than two times than Raily eco-race.

Studies on Tolerance Level Against Antheraea mylitta Cytoplasmic Polyhedrosis Virus (AmCPV) in Different Eco-races of Tropical Tasar Silkworm, Antheraea Mylitta Drury

Singh, G.P.,Zeya, S.B.,Srivastava, A.K.,Ojha, N.G.,Suryanarayana, N. Korean Society of Sericultural Science 2008 International Journal of Industrial Entomology Vol.17 No.1

Pathogenic infection in tasar silkworm, Antheraea mylitta Drury is common and there is a breed specific response regarding tolerance. Hence, the tolerance level of three eco-races of tasar silkworm viz. Daba, Sarihan and Raily to Antheraea mylitta cytoplasmic polyhedrosis virus (AmCPV) infection was tested. The survival of Daba, Sarihan and Raily eco-races was significantly different (p<0.05) when challenged with the same concentration ($1{\times}10^5$ polyhedra/ml) of AmCPV. Daba eco-race was more tolerant to the AmCPV infection having higher survival (65.7%) and $LC_{50}$ values (1000893.17 polyhedra/ml) of AmCPV followed by Sarihan eco-race (50.7% survival and $LC_{50}$ value of AmCPV 187203.6168 polyhedra/ml) and Raily eco-race (24.3% survival and $LC_{50}$ value of AmCPV 5176.37 polyhedra/ml). The tolerance level of Daba and Sarihan eco-races against AmCPV was more than two times than Raily eco-race.

Optimization and evaluation of ultra high-performance concrete

P. N. Ojha,P. N. Ojha,Abhishek Singh,Brijesh Singh,V. V. Arora 아시아콘크리트학회 2020 Journal of Asian Concrete Federation Vol.6 No.1

Ultra-High Performance Concrete (UHPC) has been defined as a cementitious based compo-site material with compressive strength above 150 MPa and enhanced durability via its discontinuous pore structure. The microstructure of UHPC is denser and more homogeneous in comparison to conventional concrete. UHPC has several advantages over conventional concrete but the use of it is limited due to the high cost and limited design codes. Methodology for production and development of UHPC needs to be established. The paper covers both optimization and evaluation of Ultra-High-Performance Concrete along with highlighting the importance of packing density, mixing procedure and curing regimes containing a high volume of mineral admixture and ultrafine materials. Cementitious content of all the mixes in the study was kept in the range of 1000 kg/m3 and water to binder ratio was kept as 0.17. This study focuses on the methodology to be adopted for optimizing the packing density of UHPC, the challenges associated with it and their influence on compressive strength.

Evaluation of Polymer Modified Mortar and Bonding Agent for Structural Repair

Ojha P N,Kaura Puneet,Singh Brijesh,Daniel Y N,Kumar Nitesh 아시아콘크리트학회 2021 Journal of Asian Concrete Federation Vol.7 No.2

Polymer modified mortar is found to be suitable for structural repair and strengthening of damage structural elements. Conventional mortar is not preferred in repair of concrete since it has inferior mechanical property and durability performance. Polymer based mortar is an alternative to conventional mortar with enhanced mechanical properties. However, there are limited specifications and guidelines available for specifying PMM mixes for structural repair work. The research work aims to evaluate the mechanical performance of polymer based mortar with varying concentration of styrene butadiene rubber latex at laboratory scale. Another aspect in repair of corrosion damage structures is the bond between the substrate concrete and repair mortar. In order to study the effectiveness of bonding agents, the performance evaluation of bonding agents has been evaluated using slant shear test and pull-off test as per ASTM C 882 and EN 1542 respectively. Findings of study indicates that at 8-10 percent concentration of dry polymer solid by cement mass in polymer based mortar is the optimum dosage. Styrene-butadiene rubber based polymer mortar showed improvement in flow in comparison to normal mortar however, mixes with crushed sand shows decrease in flow which is due to presence of more fines. Slant shear and pull-off test method shows epoxy bonding agent give better bond strength as compared to SBR latex.

Neuroprotective Effects of Antidepressants via Upregulation of Neurotrophic Factors in the MPTP Model of Parkinson’s Disease

Shadfar, S.,Kim, Y. G.,Katila, N.,Neupane, S.,Ojha, U.,Bhurtel, S.,Srivastav, S.,Jeong, G. S.,Park, P. H.,Hong, J. T. HUMANA PRESS INC 2018 Molecular Neurobiology Vol.55 No.1

<P>Neurotrophic factors are essential for neuronal survival, plasticity, and development and have been implicated in the action mechanism of antidepressants. In this study, we assessed the neurotrophic factor-inducing and neuroprotective properties of antidepressants. In the first part of the study, we found that fluoxetine, imipramine, and milnacipran (i.p., 20 mg/kg/day for 1 week or 3 weeks) upregulated brain-derived neurotrophic factor in the striatum and substantia nigra both at 1 week and 3 weeks. In contrast, an increase in the glial-derived neurotrophic factor was more obvious at 3 weeks after the antidepressants treatment. Specifically, it was found that fluoxetine and imipramine are more potent in raising the levels of neurotrophic factors than milnacipran. Furthermore, antidepressants elevated the phosphorylation of extracellular signal-regulated-protein kinase (ERK1/2) and the serine/threonine kinase Akt. In the second part of the study, we compared the neuroprotective effects of fluoxetine, imipramine, and milnacipran in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson's disease. Pretreament with fluoxetine, imipramine or milnacipran for 3 weeks reduced MPTP-induced dopaminergic neurodegeneration and microglial activation in the nigrostriatal pathway. Neurochemical analysis by HPLC exhibited that antidepressants attenuated the depletion of striatal dopamine. In consistent, beam test showed that behavioral impairment was ameliorated by antidepressants. Neuroprotective effects were more prominent in the fluoxetine or imipramine treatment group than in milnacipran treatment group. Finally, we found that neuroprotection of the antidepressants against 1-methyl-4-phenylpyridinium neurotoxicity in SH-SY5Y cells was attenuated by ERK or Akt inhibitor. These results indicate that neuroprotection by antidepressants might be associated with the induction of neurotrophic factors, and antidepressant could be a potential therapeutic intervention for treatment of Parkinson's disease.</P>

Experimental investigations on substitution of natural sand in concrete with copper slag and blast furnace slag

P.N. Ojha,A. Singh,B. SIngh 아시아콘크리트학회 2021 Journal of Asian Concrete Federation Vol.7 No.1

The constant decrease in the availability of good quality natural sand across the globe has led to increasing investigations on the possibility of utilizing by-products obtained from different industries as a replacement for natural sand. Copper slag and blast furnace slag are by-products of metallurgical processes occurring during copper and pig iron production, respectively. The substitution of natural sand using copper slag and blast furnace slag in plain and reinforced concrete has been permitted in Indian Standard IS: 383-2016 up to a certain percentage as replacing natural sand in concrete. In the present study, investigations were carried out to check the feasibility of increasing copper slag and blast furnace slag as a substitution of natural sand in concrete. Conventional (Natural) sand was replaced (by volume) with copper slag (0%, 25%, 50% & 75%), Granulated Blast Furnace Slag (GBFS) (0%, 30%, 60% & 100%) and Air-Cooled Blast Furnace Slag (ACBFS) (0%, 30%, 60% & 100%). Concrete mixes were examined by substituting conventional sand with copper and blast furnace slag in different proportions and were evaluated for different mechanical properties and durabil-ity-related parameters. Leaching studies were also carried out on selected concrete samples.

Comparison of creep models and experimental verification of creep coefficients for normal and high strength concrete

P. N. Ojha,Brijesh Singh,Abhishek Singh,Vikas Patel 아시아콘크리트학회 2020 Journal of Asian Concrete Federation Vol.6 No.2

A concrete structure when subjected to sustained load presents progressive strain over time, which is associated with the creep phenomenon. The creep characteristic of high strength concrete as-sumes importance in the back drop of increase in prestressed concrete constructions. The paper covers the comparison of creep coefficients with different creep models like Bazant’s B-3, ACI, AASHTO, GL-2000 and FIB model code 2010 for concrete mixes having water to cementitious ratio of 0.47, 0.36, 0.27 and 0.20. The comparison of different models are done for a relative humidity of 60 percent and design life of 100 years. For comparison of creep coefficient using different models the age at loading are kept as 7, 28 and 365 days. Thereafter, values are compared with experimentally obtained results of concrete mixes having water to cementitious ratio of 0.47 and 0.20 for age at loading of 28 days and up to 180 days loading period. Time induced creep strain of high strength concrete is determined using creep rig of capacity 2000 kN. Creep strains are measured at regular time intervals on concrete designed with water to cementitious ratio of 0.47 and 0.20 wherein fly ash and silica fume were also used.

Evaluation of mechanical and durability properties of con-crete made with Indian bottom ash as replacement of fine ag-gregate

P. N. Ojha,Amit Trivedi,Brijesh Singh,Abhishek Singh 아시아콘크리트학회 2020 Journal of Asian Concrete Federation Vol.6 No.2

Bottom ash is a major by-product of the coal-based power generation process and it has particle size ranging from 45 μm to 150 μm. As per current provisions of IS: 383-2016, bottom ash can be used as replacement of natural fine aggregate up to 25% in case of lean concrete (less than M15 Grade) only. However, its use in reinforced and plain concrete is not permitted. Therefore, it is imperative to study the feasibility of using coal based bottom ash as a replacement of conventional fine aggregates (i.e., natural and crushed sand) in plain and reinforced concrete to increase the utilization of this industrial byproduct. In this study, natural and crushed sand were replaced with bottom ash at various percent-ages for prepa-ration of concrete and study its effect on fresh, hardened and durability properties of concrete. Bottom ash was collected from Vindhyachal thermal power plant of India. Experimental studies were conducted at w/c ratio of 0.65 and 0.40. Concrete mixes were studied and analyzed for various mechanical and durability properties. Based on fresh concrete properties i.e., workability, slump retention and strength development, it was observed that up to 50% replacement of conventional fine aggregate with bottom ash is technically feasible.

Assessment of a fire damaged reinforced concrete building

Arup Ghatak,P.N. Ojha,Singh Brijesh,Singh Abhishek,Reddy TVG,Mohapatra B N 아시아콘크리트학회 2021 Journal of Asian Concrete Federation Vol.7 No.1

A proper condition assessment of reinforced concrete structure after a fire event involves field and laboratory work to determine the extent of fire in order to design an appropriate and cost effective repair scheme. The present paper presents a case study where an attempt has been made to carry out a condition assessment of a fire damaged building in a systematic manner. The approach adopted broadly consisted of questioning of on-site personnel, a detailed visual survey, on-site non-destructive / partially-destructive tests, collection of in-situ samples from site along with some laboratory based investigations on samples collected from site. Differential Thermal Analysis (DTA), X-Ray Diffraction (XRD) Analysis and Scanning Electron Microscopy (SEM) Imaging were conducted for microstructural characterization and analysis of concrete to correlate, corroborate and validate the results obtained through on-site assessment. Since the building was an old structure, carbonation depth in structural members was also evaluated. Finally, based on the visual inspections indicating the condition of surface and structural elements such as spalling, exposure and condition of reinforcement, cracks, honeycombing etc. along with NonDestructive Test / Laboratory test results, the repair methodology of structural members are presented.

NUMERICAL ASSESSMENT OF FILTRATION EQUATIONS

C . S . P .Ojha,N . J . D . Graham 대한환경공학회 2000 Environmental Engineering Research Vol.5 No.1