Papers by Md. Hafizur Rahman
Investigation of the right first-time distortion compensation approach in laser powder bed fusion of a thin manifold structure made of Inconel 718
Journal of Manufacturing Processes, 2021
Abstract The research work first demonstrates modelling techniques for distortion prediction of l... more Abstract The research work first demonstrates modelling techniques for distortion prediction of laser powder bed fusion (LPBF) using the inherent strain approach implemented in structural finite element analyses. The prediction of distortion is compared with experimentally measured results of a thin manifold structure made of Inconel 718. The predicted distortions were used to verify the right first-time approach for distortion compensation where the thin manifold structure was first simulated. The distortion was then compensated using mapping techniques across different source meshes, and the component was finally manufactured using LPBF. Two components were built, one with compensation and one without compensation. The results showed that the right first-time approach compensated the distortion for the majority of the part. There were areas where the compensation was not accurate due to overpredictions of the distortion.
Materials, 2021
Today, the rational combination of materials and design has enabled the development of bio-inspir... more Today, the rational combination of materials and design has enabled the development of bio-inspired lattice structures with unprecedented properties to mimic biological features. The present study aims to investigate the mechanical performance and energy absorption capacity of such sophisticated hybrid soft–hard structures with gradient lattices. The structures are designed based on the diversity of materials and graded size of the unit cells. By changing the unit cell size and arrangement, five different graded lattice structures with various relative densities made of soft and hard materials are numerically investigated. The simulations are implemented using ANSYS finite element modeling (FEM) (2020 R1, 2020, ANSYS Inc., Canonsburg, PA, USA) considering elastic-plastic and the hardening behavior of the materials and geometrical non-linearity. The numerical results are validated against experimental data on three-dimensional (3D)-printed lattices revealing the high accuracy of the ...
Agricultural Reviews, Dec 22, 2021
The diversity and abundance of insect is facing serious challenges globally in the current era. A... more The diversity and abundance of insect is facing serious challenges globally in the current era. Although the loss of biodiversity other than invertebrates has been a burning issue from a long ago, some recent reports on insect decline and its impact on agriculture have given it a crucial dimension. Studies related to insect decline revealed that 40% of insect taxa are going through the risk of decline. The current situation is the resultant of several human-influenced factors, most prominently the intensification of agriculture. Insect is one of the most diverse groups having immense effects on ecosystem as an integral part of food web which ultimately has direct effect on other organisms of environment. The most conspicuous contribution of insect is its pollination services to 80% of the flowering plants worldwide which have direct effect on human food security. Decline of pollinator insects and natural enemies of insect pests can impair the crop production due to insufficient pollination and underutilization of the insect control potential of predator insects. To resist the vulnerability of nature and to ensure food security, insect decline should be cut down by controlling anthropogenic stressors through the conservation of natural habitats, eliminating deleterious agricultural practices, implementing insect friendly policies, etc. Immediate action is necessary to alter the nature exploiting agricultural practices causing insect decline to ensure the normal functioning and integrity of entire ecosystem and for human welfare.
Promising natural products against nosocomial infections
Globally, increasing drug resistance among nosocomial infections is a growing concern for medicin... more Globally, increasing drug resistance among nosocomial infections is a growing concern for medicine, which demands effective therapeutic regimes. Along with existing major scaffolds, namely penicillin, cephalosporin, quinolones, macrolides and tetracyclines, exploring new antibiotics with novel scaffold is a pressing necessity to combat multi-drug resistant pathogens causing hospital associated infections. Therefore, this review is intended to present the latest advances in the process of drug development from natural sources. The review shows that nature can provide a variety of scaffolds, though variability in the effectiveness exists among them. Consequently, an endeavour to isolate and characterize more potential antibiotics from nature is extremely important. In this aspect, the marine environment could be a promising source as it has been comparatively ignored to date. 1. Introduction Since the first use of penicillin in the mid-twentieth century, antibiotic resistance develope...
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Papers by Md. Hafizur Rahman