http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Development of new inner diaphragms for a H-beam and composite box column joint
Mahbub Khan,Brian Uy,Jin W Kim 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.3
This paper presents an experimental and a numerical investigation of a H-beam – composite box column joint fabricated with two new inner diaphragms and a continuous inner diaphragm. The main objective of the current research project is to investigate the structural performance of the newly developed inner diaphragms under a cyclic loading protocol. Hysteretic behaviour of the composite joints is analysed to investigate the structural performance of the new and continuous inner diaphragms. This paper compares the result of the finite element (FE) models with the new and continuous inner diaphragms against their counterpart experimental results. To produce a design criterion for the newly developed inner diaphragms, yielding or failure area of the inner diaphragms under tensile stress is analysed from the FE results.
Mahbub Hasan,Jong-Gu Choi,Hafeza Akter,Sang-Suk Lee 한국자기학회 2022 Journal of Magnetics Vol.27 No.4
The suppression of cytokine storm in severe coronavirus disease 2019 (COVID-19) patients can be treated with monoclonal antibody therapy against CD3 for T cell receptor inhibition. An optimized liquid phase as a CD3 antibody-magnetic nanoparticle (Ab-MNP) conjugate can inhibit the overactivation of T cells. We aim to analyze the distribution of Fe in the spleen after acute administration of silica-conjugated amine magnetite (Fe3O4) nanoparticles (35 nm) delivered by intravenous injection. The Fe element distribution and concentration levels in spleen tissue were analyzed using energy dispersive spectroscopy (EDS) and inductively coupled plasmamass spectrometry (ICP-MS). The experimental result is a difference in the concentration of Fe elements, which was 1.89×103 mg/kg in the spleen of a control mouse not administered with MNPs, whereas increases significantly to 1.93×103 mg/kg in that of a mouse administered with MNPs. Further, time kinetic analysis of biochemical and immunological parameters is required to confirm its suitability in bio-administration.
Strengthening of steel-concrete composite beams with composite slab
Mahbube Subhani,Muhammad Ikramul Kabir,Riyadh Al-Ameri 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.1
Steel-concrete composite beam with profiled steel sheet has gained its popularity in the last two decades. Due to the ageing of these structures, retrofitting in terms of flexural strength is necessary to ensure that the aged structures can carry the increased traffic load throughout their design life. The steel ribs, which presented in the profiled steel deck, limit the use of shear connectors. This leads to a poor degree of composite action between the concrete slab and steel beam compared to the solid slab situation. As a result, the shear connectors that connects the slab and beam will be subjected to higher shear stress which may also require strengthening to increase the load carrying capacity of an existing composite structure. While most of the available studies focus on the strengthening of longitudinal shear and flexural strength separately, the present work investigates the effect of both flexural and longitudinal shear strengthening of steel-concrete composite beam with composite slab in terms of failure modes, ultimate load carrying capacity, ductility, end-slip, strain profile and interface differential strain. The flexural strengthening was conducted using carbon fibre reinforced polymer (CFRP) or steel plate on the soffit of the steel I-beam, while longitudinal shear capacity was enhanced using post-installed high strength bolts. Moreover, a combination of both the longitudinal shear and flexural strengthening techniques was also implemented (hybrid strengthening). It is concluded that hybrid strengthening improved the ultimate load carrying capacity and reduce slip and interface differential strain that lead to improved composite action. However, hybrid strengthening resulted in brittle failure mode that decreased ductility of the beam.
Timber-FRP composite beam subjected to negative bending
Mahbube Subhani,Anastasia Globa,Jules Moloney 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.73 No.3
In the previous studies, the authors proposed the use of laminated veneer lumber – carbon fiber reinforced polymer (LVL-CFRP) composite beams for structural application. Bond strength of the LVL-to-CFRP interface and flexural strengthening schemes to increase the bending capacity subjected to positive and negative moment were discussed in the previous works. In this article, theoretical models are proposed to predict the moment capacity when the LVL-CFRP beams are subjected to negative moment. Two common failure modes – CFRP fracture and debonding of CFRP are considered. The non-linear model proposed for positive moment is modified for negative moment to determine the section moment capacity. For the debonding based failure, previously developed bond strength model for CFRP-to-LVL interface is implemented. The theoretical models are validated against the experimental results and then use to determine the moment-rotation behaviour and rotational rigidity to compare the efficacy of various strengthening techniques. It is found that combined use of bi- and uni-directional CFRP U-wrap at the joint performs well in terms of both moment capacity and rotational rigidity.
Flow interference between two tripped cylinders
Md. Mahbub Alam,김상일,Dilip Kumar Maiti 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.2
Flow interference is investigated between two tripped cylinders of identical diameter D at stagger angle α= 0° ~ 180° and gap spacing ratio P* (= P/D) = 0.1 ~ 5, where α is the angle between the freestream velocity and the line connecting the cylinder centers, and P is the gap width between the cylinders. Two tripwires, each of diameter 0.1D, were attached on each cylinder at azimuthal angle b= ±30°, respectively. Time-mean drag coefficient (CD) and fluctuating drag (CDf) and lift (CLf) coefficients on the two tripped cylinders were measured and compared with those on plain cylinders. We also conducted surface pressure measurements to assimilate the fluid dynamics around the cylinders. CD, CDf and CLf all for the plain cylinders are strong function of α and P* due to strong mutual interference between the cylinders, connected to six interactions (Alam and Meyer 2011), namely boundary layer and cylinder, shear-layer/wake and cylinder, shear layer and shear layer, vortex and cylinder, vortex and shear layer, and vortex and vortex interactions. CD, CDf and CLf are very large for vortex and cylinder, vortex and shear layer, and vortex and vortex interactions, i.e., the interactions where vortex is involved. On the other hand, the interference as well as the strong interactions involving vortices is suppressed for the tripped cylinders, resulting in insignificant variations in CD, CDf and CLf with α and P*. In most of the (α, P* ) region, the suppressions in CD, CDf and CLf are about 58%, 65% and 85%, respectively, with maximum suppressions 60%, 80% and 90%.
Md Mahbub Hossain,Abida Sultana,Neetu Purohit 한국역학회 2020 Epidemiology and Health Vol.42 No.-
OBJECTIVES: Transmission of infectious diseases is often prevented by quarantine and isolation of the populations at risk. These approaches restrict the mobility, social interactions, and daily activities of the affected individuals. In recent coronavirus disease 2019 (COVID-19) pandemic, quarantine and isolation are being adopted in many contexts, which necessitates an evaluation of global evidence on how such measures impact the mental health outcomes among populations. This umbrella review aimed to synthesize the available evidence on mental health outcomes of quarantine and isolation for preventing infectious diseases. METHODS: We searched nine major databases and additional sources and included articles if they were systematically conducted reviews, published as peer-reviewed journal articles, and reported mental health outcomes of quarantine or isolation in any population. RESULTS: Among 1,364 citations, only eight reviews met our criteria. Most of the primary studies in those reviews were conducted in high-income nations and in hospital settings. These articles reported a high burden of mental health problems among patients, informal caregivers, and healthcare providers who experienced quarantine or isolation. Prevalent mental health problems among the affected individuals include depression, anxiety, mood disorders, psychological distress, posttraumatic stress disorder, insomnia, fear, stigmatization, low self-esteem, lack of self-control, and other adverse mental health outcomes. CONCLUSIONS: This umbrella review found severe mental health problems among individuals and populations who have undergone quarantine and isolation in different contexts. This evidence necessitates multipronged interventions including policy measures for strengthening mental health services globally and promoting psychosocial wellbeing among high-risk populations.