Robust design of liquid column vibration absorber in seismic vibration mitigation considering random system parameter

Debbarma, Rama,Chakraborty, Subrata Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.6

The optimum design of liquid column dampers in seismic vibration control considering system parameter uncertainty is usually performed by minimizing the unconditional response of a structure without any consideration to the variation of damper performance due to uncertainty. However, the system so designed may be sensitive to the variations of input system parameters due to uncertainty. The present study is concerned with robust design optimization (RDO) of liquid column vibration absorber (LCVA) considering random system parameters characterizing the primary structure and ground motion model. The RDO is obtained by minimizing the weighted sum of the mean value of the root mean square displacement of the primary structure as well as its standard deviation. A numerical study elucidates the importance of the RDO procedure for design of LCVA system by comparing the RDO results with the results obtained by the conventional stochastic structural optimization procedure and the unconditional response based optimization.

Growth of Time-Dependent Strain in Reinforced Cement Concrete and Pre-stressed Concrete Flexural Members

Debbarma, Swarup Rn.,Saha, Showmen Korea Concrete Institute 2012 International Journal of Concrete Structures and M Vol.6 No.2

This paper presents the differences in growth of time-dependent strain values in reinforced cement concrete (RCC) and pre-stressed concrete (PSC) flexural members through experiment. It was observed that at any particular age, the time-dependent strain values were less in RCC beams than in PSC beams of identical size and grade of concrete. Variables considered in the study were percentage area of reinforcement, span of members for RCC beams and eccentricity of applied pre-stress force for PSC beams. In RCC beams the time-dependent strain values increases with reduction in percentage area of reinforcement and in PSC beams eccentricity directly influences the growth of time-dependent strain. With increase in age, a non-uniform strain develops across the depth of beams which influence the growth of concave curvature in RCC beams and convex curvature in PSC beams. The experimentally obtained strain values were compared with predicted strain values of similar size and grade of plane concrete (PC) beam using ACI 318 Model Code and found more than RCC beams but less than PSC beams.

Influence of doping of mercury atom(s) on optoelectronic properties of binary cadmium chalcogenides - A density functional theory based investigation with different exchange-correlation functionals and including spin-orbit coupling

Manish Debbarma,Utpal Sarkar,Bimal Debnath,Sayantika Chanda,Debankita Ghosh,Rahul Bhattacharjee,Surya Chattopadhyaya 한국물리학회 2018 Current Applied Physics Vol.18 No.6

Influence of doping of mercury atom(s) on optoelectronic properties of binary cadmium chalcogenides have been investigated theoretically by designing the mercury doped cadmium chalcogenide ternary alloys in B3 phase at some specific Hg-concentrations and studying their optoelectronic properties using DFT based FP-LAPW methodology. The structural properties are computed using WC-GGA, while spin-orbit coupling included electronic and optical properties are computed using TB-mBJ, EV-GGA, B3LYP and WC-GGA exchange-correlation functionals. In addition, electronic properties of mercury chalcogenides are calculated precisely using the GGA+U functionals. The concentration dependence of lattice parameter and bulk modulus of each of the HgxCd1−xS, HgxCd1−xSe, HgxCd1−xTe alloy systems show almost linearity. For each of the alloy systems, band gap decreases almost linearly with increase in Hg-concentration in the unit cell and contribution from charge exchange to the band gap bowing is larger than that from for each of the volume deformation and structural relaxation. Also, covalent bonding exists between different constituent atoms in each compound. Optical properties of each specimen are computed from their spectra of dielectric function, refractive index, extinction coefficient, normal incidence reflectivity, optical conductivity, optical absorption coefficient and energy loss function. Several calculated results have been compared with available experimental and other theoretical data.

Density Functional Calculations of Elastic and Thermal Properties of Zinc-Blende Mercury–Cadmium-Chalcogenide Ternary Alloys

Manish Debbarma,Subhendu Das,Bimal Debnath,Debankita Ghosh,Sayantika Chanda,Rahul Bhattacharjee,Surya Chattopadhyaya 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

Density functional calculations are carried out on elastic and thermal properties of zinc-blende specimens within HgxCd1−xS,HgxCd1−xSe and HgxCd1−xTe ternary systems. Elastic stiffness constants decrease almost linearly with increasing Hg-concentrationin each system. Each cubic sample is mechanically and dynamically stable, elastically anisotropic, compressibleagainst elastic deformation, ductile and fairly plastic. The hardness of specimens in each system reduces almost linearly withenhancement in Hg-composition. Mixed kind of bonding with dominancy of ionic bonding over covalent, central nature ofinteratomic forces and bond bending over stretching exist in all specimens. In each system, covalency, Debye temperature andfrequency, Debye temperature for acoustic phonon, thermal conductivity and melting temperature of specimens decreases,while Philip ionicity and Gruneisen parameter increases with increasing Hg-concentration.

Robust design of liquid column vibration absorber in seismic vibration mitigation considering random system parameter

Rama Debbarma,Subrata Chakraborty 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.6

The optimum design of liquid column dampers in seismic vibration control considering systemparameter uncertainty is usually performed by minimizing the unconditional response of a structure withoutany consideration to the variation of damper performance due to uncertainty. However, the system sodesigned may be sensitive to the variations of input system parameters due to uncertainty. The present studyis concerned with robust design optimization (RDO) of liquid column vibration absorber (LCVA)considering random system parameters characterizing the primary structure and ground motion model. TheRDO is obtained by minimizing the weighted sum of the mean value of the root mean square displacementof the primary structure as well as its standard deviation. A numerical study elucidates the importance of theRDO procedure for design of LCVA system by comparing the RDO results with the results obtained by theconventional stochastic structural optimization procedure and the unconditional response basedoptimization.

Biodegradation of e-plastic waste by using indigenous bacteria

( Prasenjit Debbarma ),( Reeta Goel ),( M. G. H. Zaidi ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

The industrial revolution followed by technological development successively paved the way to a new era in human civilization. In no case, this revolution will decline, thus, making anthropogenic environmental pollution a major global issue. In the present scenario, e-waste accumulation and management is seriously a daunting task that needs to be tackled efficiently. Traditional methods because of their disadvantages have fuelled the use of biological tools to recover the precious metals present in e-waste and to promote the studies of bioleaching and biodegradation processes. Nevertheless, biodegradation studies of and using raw e-plastic waste is scanty in literatures. Therefore, indigenous soil bacteria are explored through enrichment culture approach followed by screening, identification, construction of bacterial consortia and their application for in situ degradation of e-plastic waste. In this study, potential bacteria namely Achromobacter insolitus strain PE2 (MF943156), Acinetobacter nosocomialis strain PE5 (MF943157), Pseudomonas lalkuanensis Novel strain PE8 (MF943158/CP043311), Pseudomonas aeruginosa strain PE10 (MF943159) and Stenotrophomonas pavanii strain PE15 (MF943160) are identified as e-plastic degraders. Their 16S rDNA sequences have been deposited in NCBI GenBank database for their easy accessibility to scientific community. Pseudomonas lalkuanensis sp. nov. strain PE8 (CP043311) was significantly found to be novel culture and its complete genome sequencing has been done and published. Moreover, two new novel bacterial consortia have been developed viz. C-1 and C-2 for biodegradation of e-waste. Nonetheless, one technology/patent which relates to a direct and standardized protocol for e-waste biodegradation in presence of bacterial consortium have recently published by Indian patent office (201811049946) which can be explored further for sustainable management of e-waste. Conclusively, the findings from this research work could be explored for large scale biodegradation of synthetic polymeric e-waste subsequently. Therefore, this study provides degradation and/or fermentation platform for biological recycling of e-waste under in situ conditions. Further, it will enrich the e-plastic degrading bacteria database and this will provide the directive for development of e-plastic degrading bacterial consortia for sustainable strategies.

Growth of Time-Dependent Strain in Reinforced Cement Concrete and Pre-stressed Concrete Flexural Members

Swarup Rn. Debbarma,Showmen Saha 한국콘크리트학회 2012 International Journal of Concrete Structures and M Vol.6 No.2

This paper presents the differences in growth of time-dependent strain values in reinforced cement concrete (RCC) and pre-stressed concrete (PSC) flexural members through experiment. It was observed that at any particular age, the time-dependent strain values were less in RCC beams than in PSC beams of identical size and grade of concrete. Variables considered in the study were percentage area of reinforcement, span of members for RCC beams and eccentricity of applied pre-stress force for PSC beams. In RCC beams the time-dependent strain values increases with reduction in percentage area of reinforcement and in PSC beams eccentricity directly influences the growth of time-dependent strain. With increase in age, a non-uniform strain develops across the depth of beams which influence the growth of concave curvature in RCC beams and convex curvature in PSC beams. The experimentally obtained strain values were compared with predicted strain values of similar size and grade of plane concrete (PC) beam using ACI 318 Model Code and found more than RCC beams but less than PSC beams.

Pressure-settlement behavior of square and rectangular skirted footings resting on sand

Khatri, Vishwas Nandkishor,Debbarma, S.P.,Dutta, Rakesh Kumar,Mohanty, Bijayananda Techno-Press 2017 Geomechanics & engineering Vol.12 No.4

The present study deals with the Pressure-settlement behavior of square and rectangular skirted footing resting on sand and subjected to a vertical load through a laboratory experimental study. A series of load tests were conducted in the model test tank to evaluate the improvement in pressure-settlement behavior and bearing capacity of square and rectangular model footings with and without structural skirt. The footing of width 5 cm and 6 cm and length/width ratio of 1 and 2 was used. The relative density of sand was maintained at 30%, 50%, 70%, and 87% respectively. The depth of skirt was varied from 0.25 B to 1.0 B. All the tests were carried out using a strain controlled loading frame of 50 kN capacity. The strain rate for all test was kept 0.24 mm/min. The results of present study reveal that, the use of structural skirt improves the bearing capacity of footing significantly. The improvement in bearing capacity was observed almost linearly proportional to the depth of skirt. The improvement in bearing capacity of skirted footings over footing without skirt was observed in the range of 33.3% to 68.5%, 68.9% to 127% and 146.7% to 262% for a skirt depth of 0.25 B, 0.50 B and 1.0 B respectively. The skirted footings were found more effective for sand at relative density of 30% and 50% than at relative density of 70% and 87%. The bearing capacity was found to increase linearly with footing width for footings with and without skirts. This observation was found to be consistent for footings with different skirt depths and for relative density of sand i.e., 30%, 50%, 70%, and 87%. The obtained results from the study for footing with and without skirts were comparable with available solutions from literature.

Flipped Reposition Laminoplasty for Excision of Intradural Extramedullary Tumors in the Thoracolumbar Spine: A Case Series of 14 Patients

Ramesh Kumar,Ijack Debbarma,Tankeshwar Boruah,Atul Sareen,Mohit Kumar Patralekh,Ashish Dagar,Shaffaf Abdul Kareem 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.3

Study Design: A retrospective study was done to assess the outcome of the new technique of flipped reposition laminoplasty for excision of intradural extramedullary (IDEM) spinal tumors of the thoracolumbar region.Purpose: To describe flipped reposition laminoplasty technique and evaluate its outcomes. Overview of Literature: Laminectomy has been the conventional approach for the surgical excision of IDEM spinal tumors, but it has potential postoperative complications. Laminoplasty maintains the posterior arch of the spine and avoids complications seen in Laminectomy, such as instability, epidural scarring, and kyphotic deformity.Methods: Fourteen patients (nine females and five males) diagnosed with IDEM tumors of the thoracolumbar region operated between 2016 and 2018 were included in this study. Pathologically, five cases were schwannomas; four cases were meningiomas; two cases were ependymomas; and one case each was lymphoma, neurofibroma, and teratoma. All patients had their neurological deficits documented using the American Spinal Injury Association (ASIA) impairment scale. After completion of all preanesthetic formalities, the patients were operated upon by a single surgeon using the flipped reposition laminoplasty technique. Follow-up was done at 1, 3, 6, and 12 months post operation and yearly thereafter.Results: The mean age of the patients was 35.28 years (14–65 years), and the mean follow-up duration was 17 months (6–26 months). Two patients were assessed with ASIA grade A neurology, one patient improved to ASIA grade B, whereas the other did not improve. Two patients improved from ASIA grade B to ASIA grade D, and seven patients with ASIA grades C and D improved to ASIA grade E. Fusion at the osteotomy site was seen in 92.85% (13 out of 14) cases on one side within 6 months post operation. Fusion was seen in all the cases within 1 year post operation.Conclusions: Flipped reposition laminoplasty is an excellent technique providing adequate exposure and additional stability postoperatively.

Molecular genetics and functional genomics of abiotic stressresponsive genes in oilseed rape (Brassica napus L.): a review of recent advances and future

Channakeshavaiah Chikkaputtaiah,Johni Debbarma,Indrani Baruah,Lenka Havlickova,Hari Prasanna Deka Boruah,Vladislav Curn 한국식물생명공학회 2017 Plant biotechnology reports Vol.11 No.6

Abiotic stresses are the key factors which negatively influence plant development and productivity and are the main cause of extensive agricultural production losses worldwide. Brassica napus is an oilseed crop of global economic significance and major contributor to the total oilseed production, quite often encounters abiotic stresses, resulting in reduced agricultural productivity. Hence, there is an immediate need being felt to raise B. napus cultivars which would be more suitable for various abiotic stress conditions presently and in the years to come. Biotechnology and molecular plant breeding has emerged as an important tool for molecular understanding of plant response to various abiotic stresses. Currently, various stress-responsive genes and mechanisms have been identified and functionally characterized in model plant Arabidopsis and other major crop plants such as Oryza sativa and Zea mays. However, very inadequate success has been achieved in this direction in a major oilseed crop such as B. napus. In this review, we present the latest methods and approaches of studying abiotic stress in B. napus. In this review, we describe the genes functioning as markers for crop breeding and discuss the recent progress and advances in genome editing by break through CRISPR/Cas9 multigene– multiplex approaches for developing multiple abiotic stress tolerance with our on-going research as a scheme. We also throw some light on molecular genetics, plant breeding and abiotic stress biotechnology of B. napus which offer a new prospective on the research directions for the practical plant breeding and functional genomics of B. napus in response to different abiotic stress conditions.