Numerical simulation of an external prestressing technique for prestressed concrete end block

Murthy, A. Rama Chandra,Ganapathi, S. Chitra,Saibabu, S.,Lakshmanan, N.,Jayaraman, R.,Senthil, R. Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.33 No.5

This paper presents the details of finite element (FE) modeling and analysis of an external prestressing technique to strengthen a prestressed concrete (PSC) end block. Various methods of external prestressing techniques have been discussed. In the proposed technique, transfer of external force is in shear mode on the end block creating a complex stress distribution. The proposed technique is useful when the ends of the PSC girders are not accessible. Finite element modeling issues have been outlined. Brief description about material nonlinearity including key aspects in modeling inelastic behaviour has been provided. Finite element (FE) modeling including material, loading has been explained in depth. FE analysis for linear and nonlinear static analysis has been conducted for varying external loadings. Various responses such as out-of-plane deformation and slip have been computed and compared with the corresponding experimental observations. From the study, it has been observed that the computed slope and slip of the steel bracket under external loading is in good agreement with the corresponding experimental observations.

Remaining life prediction of concrete structural components accounting for tension softening and size effects under fatigue loading

Murthy, A. Rama Chandra,Palani, G.S.,Iyer, Nagesh R. Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.32 No.3

This paper presents analytical methodologies for remaining life prediction of plain concrete structural components considering tension softening and size effects. Non-linear fracture mechanics principles (NLFM) have been used for crack growth analysis and remaining life prediction. Various tension softening models such as linear, bi-linear, tri-linear, exponential and power curve have been presented with appropriate expressions. Size effect has been accounted for by modifying the Paris law, leading to a size adjusted Paris law, which gives crack length increment per cycle as a power function of the amplitude of a size adjusted stress intensity factor (SIF). Details of tension softening effects and size effect in the computation of SIF and remaining life prediction have been presented. Numerical studies have been conducted on three point bending concrete beams under constant amplitude loading. The predicted remaining life values with the combination of tension softening & size effects are in close agreement with the corresponding experimental values available in the literature for all the tension softening models.

Meta-analysis of GSTM1 and GSTT1 Polymorphisms and Risk of Nasopharyngeal Cancer

Murthy, Archana Krishna,Kumar, Vinod,Suresh, K.P. Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.3

Background: Studies of associations between genetic polymorphism of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) with risk of nasopharyngeal cancer (NPC) have generated conflicting results. Thus, a meta-analysis was performed to clarify the effects of GSTM1 and GSTT1 polymorphisms on the risk of developing NPC. Materials and Methods: A literature search in two electronic databases namely PubMed and EMBASE up to December 2012 was conducted and eligible papers were finally selected based on the inclusion and exclusion criteria. The pooled odds ratio (OR) and presence of heterogeneity and publication bias in those studies were evaluated. Results: A total of 9 studies concerning nasopharyngeal cancer were evaluated. Analyses of all relevant studies showed increased NPC risk to be significantly associated with the null genotypes of GSTMI (OR=1.43, 95%CI 1.24-1.66) and GSTT1 (OR=1.28, 95%CI=1.09-1.51). In addition, evidence of publication bias was detected among the studies on GSTM1 polymorphism. Conclusions: This meta-analysis demonstrated the GSTM1 and GSTT1 null genotypes are associated with an increased risk of NPC.

Barriers to Realization of Forestry Mitigation Potential in India

Murthy, Indu K,Prasad KV, Devi Institute of Forest Science 2018 Journal of Forest Science Vol.34 No.5

Implementation of mitigation options on land is important for realisation of the goals of the Paris Agreement to stabilize temperature at $2^{\circ}C$. In India, the Intended Nationally Determined Contribution (INDC) targets include a forestry goal of creation of carbon sinks of 2.5 to 3 billion tonnes by 2030. There are however, multiple barriers to implementation of forestry mitigation options in India. They include environmental, social, financial, technological and institutional barriers. The barriers are varied not just across land categories but also for a land category depending on its regional location and distribution. In addition to these barriers is the impeding climate change that places at risk realisation of the mitigation potential as rising temperatures, drought, and fires associated with projected climate change may lead to forests becoming a weaker sink or a net carbon source before the end of the century.

aarvee associates

Murthy, M 서울행정학회 2014 서울행정학회 학술대회 발표논문집 Vol.2014 No.7

Prediction of flexural behaviour of RC beams strengthened with ultra high performance fiber reinforced concrete

Murthy A, Ramachandra,Aravindan, M.,Ganesh, P. Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.3

This paper predicts the flexural behaviour of reinforced concrete (RC) beams strengthened with a precast strip of ultra-high performance fiber-reinforced concrete (UHPFRC). In the first phase, ultimate load capacity of preloaded and strengthened RC beams by UHPFRC was predicted by using various analytical models available in the literature. RC beams were preloaded under static loading approximately to 70%, 80% and 90% of ultimate load of control beams. The models such as modified Kaar and sectional analysis predicted the ultimate load in close agreement to the corresponding experimental observations. In the second phase, the famous fatigue life models such as Papakonstantinou model and Ferrier model were employed to predict the number of cycles to failure and the corresponding deflection. The models were used to predict the life of the (i) strengthened RC beams after subjecting them to different pre-loadings (70%, 80% and 90% of ultimate load) under static loading and (ii) strengthened RC beams after subjecting them to different preloading cycles under fatigue loading. In both the cases precast UHPFRC strip of 10 mm thickness is attached on the tension face. It is found that both the models predicted the number of cycles to failure and the corresponding deflection very close to the experimental values. It can be concluded that the models are found to be robust and reliable for cement based strengthening systems also. Further, the Wang model which is based on Palmgren-Miner's rule is employed to predict the no. of cycles to failure and it is found that the predicted values are in very good agreement with the corresponding experimental observations.

Ginsenosides: prospective for sustainable biotechnological production

Murthy, Hosakatte Niranjana,Georgiev, Milen I.,Kim, Yun-Soo,Jeong, Cheol-Seung,Kim, Sun-Ja,Park, So-Young,Paek, Kee-Yoeup Springer-Verlag 2014 Applied microbiology and biotechnology Vol.98 No.14

<P>Panax ginseng C.A. Meyer (ginseng) is a well-known medicinal plant that has been traditionally used in the oriental countries for centuries. Wild ginseng is a scarce and rare commodity. Field cultivation of the ginseng plant is a time-consuming and labor-intensive process. Ginsenosides, a group of glycosylated triterpenes, also known as saponins, are the principal bioactive constituents of ginseng. The use of cell and organ culture processes has been sought as a potential alternative for the efficient mass production of ginseng raw material. Various bioprocessing strategies have been developed to date. Cells and adventitious roots have been cultured in large-scale bioreactors and various strategies have been developed accordingly for the enhancement of biomass and ginsenoside accumulation. This review highlights the recent progress in the cultivation of ginseng cell and organ cultures for the production of ginsenosides from bioreactor cultures. In addition, the metabolism and biochemistry of ginsenoside biosynthesis, genomic and proteomic studies in ginseng, metabolic engineering, biosafety, toxicological evaluation, and efficacy assessment of ginseng raw material are also summarized and thoroughly discussed.</P>

Effect of steel fibres and nano silica on fracture properties of medium strength concrete

Murthy, A. Ramachandra,Ganesh, P. Techno-Press 2019 Advances in concrete construction Vol.7 No.3

This study presents the fracture properties of nano modified medium strength concrete (MSC). The nano particle used in this study is nano silica which replaces cement about 1 and 2% by weight, and the micro steel fibers are added about 0.4% volume of concrete. In addition to fracture properties, mechanical properties, namely, compressive strength, split tensile strength, and flexural strength of nano modified MSC are studied. To ensure the durability of the MSC, durability studies such as rapid chloride penetration test, sorptivity test, and water absorption test have been carried out for the nano modified MSC. From the study, it is observed that significant performance improvement in nano modified MSC in terms of strength and durability which could be attributed due to the addition pozzolanic reaction and the filler effect of nano silica. The incorporation of nano silica increases the fracture energy about 30% for mix without nano silica. Also, size independent fracture energy is arrived using two popular methods, namely, RILEM work of fracture method with $P-{\delta}$ tail correction and boundary effect method. Both the methods resulted in nearly the same size-independent $G_F$ irrespective of the notch to depth ratio of the same specimen. This shows evidence that either of the two procedures could be used in practice for analysis of cracked concrete structures.

Synthetic Approaches for the Nanoencapsulation of Fullerenes

Murthy, C. N.,Geckeler, K. E. WILEY-VCH Verlag 2006 Chem Inform Vol.37 No.41

<P>ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.</P>

Production of secondary metabolites from cell and organ cultures: strategies and approaches for biomass improvement and metabolite accumulation

Murthy, Hosakatte Niranjana,Lee, Eun-Jung,Paek, Kee-Yoeup Springer-Verlag 2014 Plant cell, tissue and organ culture Vol.118 No.1