Atikur Rahman - Academia.edu (original) (raw)

Papers by Atikur Rahman

Pierre Lecointre,1,2 Timothée Mouterde,1,2 Antonio Checco,3 Charles T. Black,4 Atikur Rahman,5 Ch... more Pierre Lecointre,1,2 Timothée Mouterde,1,2 Antonio Checco,3 Charles T. Black,4 Atikur Rahman,5 Christophe Clanet,1,2 and David Quéré1,2,* 1Physique et Mécanique des Milieux Hétérogènes, UMR 7636 du CNRS, ESPCI, 75005 Paris, France 2Laboratoire d’Hydrodynamique de l’X, UMR 7646 du CNRS, École polytechnique, 91128 Palaiseau, France 3Mechanical Engineering Department, Stony Brook University, Stony Brook, New York 11794, USA 4Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA 5Department of Physics, Indian Institute of Science Education and Research (IISER)-Pune, Maharashtra 411008, India

Bulletin of the American Physical Society, 2015

Runoff from open animal feeding operation is a major source of non-point pollution. Vegetative fi... more Runoff from open animal feeding operation is a major source of non-point pollution. Vegetative filter strips (VFS) are one of the effective ways in controlling non-point source pollution. In this study, performance of a vegetative filter strip situated at down slope end of a beef feedlot was evaluated under eastern North Dakota climatic conditions. Two automatic ISCO samplers were installed to collect runoff water entering and leaving the vegetative filter strip. Runoff samples were analyzed for solids, nutrients, pH, and conductivity using standard methods. Results indicated that VFS was effective in reducing concentration of total solids (TS) by 33.7%, total suspended solids (TSS) by 68.0%, total phosphorous (TP) by 29.9%, ortho-phosphorous (OP) by 19.3%, ammonium nitrogen (NH4-N) by 31.8%, total Kjeldahl nitrogen (TKN) by 35.6%, and potassium (K) by 19.8%. Nitrate nitrogen (NO3-N) concentrations at the outlet samples increased as expected, and the buffer was not effective in redu...

Field Crops Research, 2021

Abstract Increasing Boro (irrigated dry season) rice production in the saline coastal zone (CZ) i... more Abstract Increasing Boro (irrigated dry season) rice production in the saline coastal zone (CZ) is part of the Bangladesh Government strategy for meeting its Sustainable Development Goals (SDG’s). However salinity and fresh water shortages during the Rabi (dry) season result in large areas of land remaining uncropped and under-utilised in the CZ, with crop yields below potential. We evaluated a range of options for increasing Boro rice production and farmer profit in this region. These included changes to sowing dates in combination with different polder sluice-gate management strategies aimed at increasing irrigation water supply and cropping area. We employed a case-study approach, using a combination of field experimentation, APSIM cropping systems modelling, and economic analysis, focussing on Satkhira District, Khulna Division. We found the most profitable strategies were to establish Boro rice crops in mid-November, around a month earlier than current farmer practice, on larger portions of land irrigated using river water supplied via the polder canal network. This offers significant increases in both farmer profit and regional production (up to 4x). The reasons for the gains are dual – (1) potential rice yields are higher; and (2) early sowing unleashes the potential of extensive fresh-water availability to greatly increase cropping area, because at that time river salinity levels are low and unlimited amounts of suitable irrigation water are available. Under current practices with later sowing dates (around mid-December), these early-season water resources are hardly used. To achieve the advantages of early-sowing, certain system changes are necessary. Firstly, farmers must adopt early-maturing transplanted Aman (T. Aman) rice cultivars in the monsoon season. Secondly, they must synchronise agronomic timings with fellow farmers in polder sluice-gate management zones to allow efficient gate operation and timely drainage of stagnant monsoon waters from fields in October, followed by early-season establishment of Boro rice crops. The applicability of our findings will vary geographically in the CZ, as a function of prevailing dynamics of river salinity, water tables, soils and climate. To understand the economics at a national scale, our analysis should be extended on a regional basis to estimate regional production gains possible, as well as to assess environmental health risks – particularly related to increased salinization of polder soils. Our analysis suggests that substantial investment in further research and achieving the required social and agronomic changes may be warranted.

Journal of The Institution of Engineers (India): Series D, 2020

Cerium oxide film was developed on Superni-75, via electroless method using cerium acetate and tr... more Cerium oxide film was developed on Superni-75, via electroless method using cerium acetate and triethanolamine. Hot corrosion studies were conducted on bare substrate and the cerium oxide-coated superalloy after exposure to a molten salt environment of Na 2 SO 4-60%V 2 O 5 at 900°C under cyclic conditions. The weight change measurements were taken to calculate the cyclic hot corrosion kinetics of the coatings at 900°C. The structural features of the samples were characterized by SEM/EDS and XRD. It was observed that the corrosion rate of cerium oxide-coated superalloy is lower than that of the uncoated superalloy due to the formation of dense and protective oxide scale over the surface of the coatings. In spite of the combined effect of thermal cycling and an aggressive environment, the weight variation per unit area was found to decrease as the cerium concentration increased. Cerium oxide film was able to impede the movement of ions, thereby reducing the short-circuit diffusion of ions. Also, there was an improvement in resistance to spallation in the coated specimens with increase in cerium concentration.

Environmental Engineering and Management Journal, 2013

Nutrient runoff is an environmental concern. There is a need for a robust method of predicting nu... more Nutrient runoff is an environmental concern. There is a need for a robust method of predicting nutrient concentrations in runoff from feedlots to facilitate management practices. To investigate the feasibility of using multiple linear regression (MLR) and artificial neural network (ANN) in predicting nutrients in runoff, simple water quality paramters (e.g., pH and EC) of runoff from a feedlot in North Dakota, USA, were used to train an ANN. Both models accurately predicted potassium concentration based on inputs pH and electrical conductivity (EC). The ANN approach, however, used in this study gave a better prediction than multiple linear regression models. It may be concluded that ANN may be a useful tool for predicting nutrients concentration in runoff using pH and EC, when expensive and time-consuming analytical data are not available, and this information may be used for implementing measures to minimize environmental concerns.

Sādhanā, 2019

The present work was aimed at analysing the oxidation behaviour of three nickel-based superalloys... more The present work was aimed at analysing the oxidation behaviour of three nickel-based superalloys-Superni 718, Superni 75 and Superni 750, by conducting in-situ study in the secondary chamber of a medical waste incinerator at 800-850°C for 1000 h. It was observed that among the three superalloys, Superni 75 is best suited for such an environment. This was concluded by comparing the weight change after 100 h for total 1000 h, constituting 10 thermal cycles. The morphology of the oxide scale formed on the substrate was analysed using FE-SEM. The elemental composition was obtained by EDS. The depth profiling of the scale was done using the XPS technique. The chemical composition was also examined by the XRD analysis. The superior oxidation property of Superni 75 is due to the higher Ni-Cr content. The oxidation resistance of the nickel-based superalloys in the aggressive environment of medical waste incinerator is attributed to the presence of chromia oxide-Cr 2 O 3 and spinel NiCr 2 O 4 .

Nature Materials, 2017

Nanometre-scale features with special shapes impart a broad spectrum of unique properties to the ... more Nanometre-scale features with special shapes impart a broad spectrum of unique properties to the surface of insects. These properties are essential for the animal's survival, and include the low light reflectance of moth eyes, the oil repellency of springtail carapaces and the ultra-adhesive nature of palmtree bugs. Antireflective mosquito eyes and cicada wings are also known to exhibit some antifogging and self-cleaning properties. In all cases, the combination of small feature size and optimal shape provides exceptional surface properties. In this work, we investigate the underlying antifogging mechanism in model materials designed to mimic natural systems, and explain the importance of the texture's feature size and shape. While exposure to fog strongly compromises the water-repellency of hydrophobic structures, this failure can be minimized by scaling the texture down to nanosize. This undesired e ect even becomes non-measurable if the hydrophobic surface consists of nanocones, which generate antifogging e ciency close to unity and water departure of droplets smaller than 2 µm. A lthough textured hydrophobic materials show spectacular water-repellency, which causes millimetre-size drops to bounce off such surfaces 1,2 , they generally get wet when exposed to fogs or to humid atmosphere 3-9. Droplets of a size comparable to that of the surface features can nucleate and grow within-rather than atop-the texture, and this so-called Wenzel state destroys superhydrophobicity 6-9. Water strongly pinned in this way remains stuck as dew accumulates, resulting in hydrophiliclike behaviour. A large drop contacting this infused solid will also be pinned, owing to the multiple bridges provided by the subjacent wet patches. In humid air, water drops of any size between mist and rain get captured on the previously repellent material, even when it is tilted 3-5. These considerations suggest that more effective antifogging might result from scaling the texture sizes to the submicrometre range 10,11 , which has other practical benefits such as rendering the coating robust against pressure 12 , or enhancing optical transparency 13 and heat transfer 14,15. It has been reported that droplets of 10-100 µm condensing on nanotextures can remain mobile enough to allow an efficient transfer of surface energy gained in coalescence to kinetic energy, causing them to sometimes jump off the surface 15-18. This property has been observed on solids with two-tier roughness 19-21 or colloids 22 , and on cicadae wings covered with nanocones 11-thus potentially self-cleaned by fogs.

Nature Communications, 2016

Self-assembly is a powerful paradigm, wherein molecules spontaneously form ordered phases exhibit... more Self-assembly is a powerful paradigm, wherein molecules spontaneously form ordered phases exhibiting well-defined nanoscale periodicity and shapes. However, the inherent energyminimization aspect of self-assembly yields a very limited set of morphologies, such as lamellae or hexagonally packed cylinders. Here, we show how soft self-assembling materials-block copolymer thin films-can be manipulated to form a diverse library of previously unreported morphologies. In this iterative assembly process, each polymer layer acts as both a structural component of the final morphology and a template for directing the order of subsequent layers. Specifically, block copolymer films are immobilized on surfaces, and template successive layers through subtle surface topography. This strategy generates an enormous variety of three-dimensional morphologies that are absent in the native block copolymer phase diagram.

Computational Condensed Matter, 2016

A new Laves phase superconductor NbBe 2 , prototype with MgCu 2 , having maximum T c ~2.6 K has b... more A new Laves phase superconductor NbBe 2 , prototype with MgCu 2 , having maximum T c ~2.6 K has been reported very recently. Based on first-principle calculations, we systematically study the structural, elastic, mechanical, electronic, thermal and superconducting properties of the newly reported superconducting intermetallic compound NbBe 2. The study of Cauchy pressure and Pugh's ratio reveal the brittle manner of NbBe 2. This compound exhibits metallic conductivity and the Nb-Be bonds have a covalent feature in which the contribution of Nb-4d state is dominant near Fermi level. The Debye temperature of NbBe 2 is 664.54 K calculated using our elastic constants data. We obtain the heat capacity (C v) of NbBe 2 at ambient condition is 20.75 cal/cell K using quasi-harmonic model. Finally, we investigate the electronphonon coupling constant, phonon dispersion curve and density of states which indicates that the compound under study is a weakly coupled BCS superconductor.

Clin Cancer Res 7 3698 S 3698 S, Nov 1, 2001

American Scientific Research Journal For Engineering Technology and Sciences, Feb 19, 2015

The recent discovery of iron-based superconductors has evoked eagerness for extensive research on... more The recent discovery of iron-based superconductors has evoked eagerness for extensive research on these materials because they form the second high-temperature superconductor family after the copper oxide superconductors and impart an expectation for materials with a higher transition temperature (T c). It has also been clarified that they have peculiar physical properties including an unconventional pairing mechanism and superconducting properties preferable for application such as a high upper critical field and small anisotropy. Iron-based superconductors are the new star in the world of solid state physics. The stunning discovery of superconductivity in iron-based materials has exposed a new family of high-temperature superconductors with properties that are both similar to and different than those of the copper-oxide family of superconductors. With transition temperatures approaching the boiling point of liquid nitrogen, these materials promise to provide a rich playground to study the fundamentals of superconductivity, while advancing the prospects for widespread technological applications. In this review paper we have studied the iron-based superconductors, their classifications, different properties and applications.

Scientific Reports, 2016

The dependence of the wettability of graphene on the nature of the underlying substrate remains o... more The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.

Nature Communications

Materials providing broadband light antireflection have applications as highly transparent window... more Materials providing broadband light antireflection have applications as highly transparent window coatings, military camouflage, and coatings for efficiently coupling light into solar cells and out of light emitting diodes. In this work, densely packed silicon nanotextures with feature sizes smaller than 50 nanometers enhance the broadband antireflection compared to that predicted by their geometry alone. A significant fraction of the nanotexture volume comprises a surface layer whose optical properties differ substantially from those of the bulk, providing the key to improved performance. The nanotexture reflectivity is quantitatively well modeled after accounting for both its profile and changes in refractive index at the surface. We employ block copolymer self assembly for precise and tunable nanotexture design in the range of ~10 to 70 nanometers across macroscopic solar cell areas. Implementing this efficient antireflection approach in crystalline silicon solar cells significan...

Environmental engineering and management journal

Nature Communications, 2015

Self-assembly of block copolymers is a powerful motif for spontaneously forming well-defined nano... more Self-assembly of block copolymers is a powerful motif for spontaneously forming well-defined nanostructures over macroscopic areas. Yet, the inherent energy minimization criteria of self-assembly give rise to a limited library of structures; diblock copolymers naturally form spheres on a cubic lattice, hexagonally packed cylinders and alternating lamellae. Here, we demonstrate multicomponent nanomeshes with any desired lattice symmetry. We exploit photothermal annealing to rapidly order and align block copolymer phases over macroscopic areas, combined with conversion of the self-assembled organic phase into inorganic replicas. Repeated photothermal processing independently aligns successive layers, providing full control of the size, symmetry and composition of the nanoscale unit cell. We construct a variety of symmetries, most of which are not natively formed by block copolymers, including squares, rhombuses, rectangles and triangles. In fact, we demonstrate all possible two-dimensional Bravais lattices. Finally, we elucidate the influence of nanostructure on the electrical and optical properties of nanomeshes.

American Journal of Modern Physics, 2015

The term "MAX phase" refers to a very interesting and important class of layered ternary transiti... more The term "MAX phase" refers to a very interesting and important class of layered ternary transition-metal carbides and nitrides with a novel combination of both metal and ceramic-like properties that have made these materials highly regarded candidates for numerous technological and engineering applications. A relatively new class of transition metal layered compounds M n+1 AX n , (MAX phases) where M is an early transition metal, A is a group A element most likely Al, and X is C or N with n = 1, 2, 3………..Due to their unique structural arrangements and directional bonding, these ternary compounds possess some very outstanding mechanical and chemical properties such as damage-resistance, oxidation resistance, excellent thermal and electric conductivity, machinability, and fully reversible dislocation-based deformation. These properties can be explored in the search for new phases and their composites to meet the performance goals of advanced materials with applications in fossil energy conversion technology. Systematic and detailed computational studies on MAX phase compounds can provide fundamental understanding of the key characteristics that lead to these desirable properties and to the discovery of other new and better alloys.In this paper, we review on structural, electronic, optical and mechanical properties of around 50 MAX phase compounds and their applications. From the comparative study on the result of these compounds we think that this paper will enable to researcher to explore and predict new MAX phases and new composite alloys with better physical properties as advanced materials for various applications at extreme conditions.

Journal of Advanced Physics, 2015

Journal of Nanostructure in Chemistry, 2015

Magnesium aluminate spinel nanoparticles with different concentration of alumina(x = 0.1, 0.2, 0.... more Magnesium aluminate spinel nanoparticles with different concentration of alumina(x = 0.1, 0.2, 0.3, 0.4 and 0.54) are synthesized by solid state reaction method. The synthesized products are characterized by powder X-ray diffraction and UV-Vis spectroscopy. The prepared nanoparticles exhibit a cubic structure with average crystallite size 25.4, 30.1, 31.2, 29.6 and 19.5 nm, respectively. The band gap values of magnesium aluminate spinel nanopartciles are found to increases with increase in alumina concentration(x = 0.1 to 0.54). Photocatalytic studies of the magnesium aluminate spinel nanoparticles are done by taking methylene blue as pollutants. Their degradation behavior has been discussed.

Surface Engineering, 2011

Oxidation behaviour of low carbon and low alloyed steels at different Ni-Cr coatings thickness ar... more Oxidation behaviour of low carbon and low alloyed steels at different Ni-Cr coatings thickness are studied, and also investigated the resistance offered by different coating thickness. Hardness of low alloy steel was increased from 202 to 342 VHN whereas that of mild steel was increased from 148 to 309 VHN after the application of coatings. Parabolic rate constant (Kp) for high temperature oxidation of bare, 200-250µm, and 250-300µm thick Ni-Cr coated low alloy steel were calculated to be 787.192, 0.235608, and 0.501787 (×10-10g2cm-4s-1) respectively, whereas that of mild steel were calculated to be 1104.49, 0.0309172, and 0.0978113 (×10-10 g2cm-4s-1) respectively.