IR@CMERI - The Central Mechanical Engineering Research Institute (CSIR)
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Ethylenediamine assisted functionalization of self-organized poly (D, L-lactide-co-glycolide) patterned surface to enhance cancer cell isolation
No full textAbstract Protein functionalized micro-scale patterned structures are developed using a biocompatible polymer PLGA (poly (D, L-lactide-co-glycolide)) via thin film dewetting and by step-wise chemical conjugations with EDA (ethylenediamine) and anti-EpCAM (Epithelial Cell Adhesion olecule) antibodies to target the epithelial cell adhesion molecules of cancer cells. The effectiveness of such protein functionalized patterned surface is checked through cell isolation process using blood samples spiked with different cancer cells such as MCF-7, A549, MDA-MB-231. An efficient capture yield of 92% is obtained with MCF-7 cells over a two hour incubation time. The study demonstrates the effects of cell concentration and incubation time on the binding of cancer cells to the modified patterned surfaces. For the first time, a simple and inexpensive method is reported to fabricate functionalized PLGA patterned surface for an efficient isolation of cancer cells from diluted blood samples. The method shows the potential to be used as an effective platform for the development of an improved circulating tumor cell (CTC) isolation device from the clinical blood sample
Development of carbon coated NiS2 as positive electrode material for high performance asymmetric supercapacitor
No full textFacile synthesis of carbon coated NiS2 composite through one-step hydrothermal process was demonstrated. Three different composites were synthesized (NCC1, NCC2, and NCC3) by changing the stoichiometric ratio of nickel, sulphur and carbon precursor. The particle size and its distribution depend on the amount of carbon precursor and metal sulphides ratio. The carbon coating on metal sulphides significantly augmented the electrochemical properties of the supercapacitor electrodes. It was found that in an optimum ratio of carbon precursor and metal sulphide, the particles were formed uniformly as seen in the NCC2 composites and exhibited the specific capacitance of 2212 F g−1 at a specific current of 2 A g−1 in a three-electrode system. An asymmetric supercapacitor (ASC) device was fabricated with NCC2 as positive electrode and thermally reduced graphene oxide as negative electrode. The ASC device showed high specific capacitance of 184.9 F g−1 at 3 A g−1 and specific energy of 50.35 Wh Kg−1 at a specific power of ~2.26 kW kg−1. It showed ~83% retention in specific capacitance after 6000 charge-discharge cycles. High specific capacitance, specific energy and specific power of the ASC device confirmed that the NCC2 composite could be used as energy storage electrode materials for supercapacitor applications
n-alkylamino analogs of Vitamin K3: Electrochemical, DFT and anticancer activity of their oxidized and one electron reduced form
No full textSynthesis, characterization and anticancer activity of reduced form of n-alkylamino analogs of Vitamin K3 (1Na to 8Na) are undertaken. Molecular structure and molecular association of oxidized form of 2-ethylamino-3-methyl-1,4-naphthoquinone (2) and 2-hexylamino-3-methyl-1,4-naphthoquinone (6) were studied by single crystal X-ray analysis. 2 crystallize in monoclinic C2/c and 6 in P21 space group. The reduced form of eight homologated analogs of 2-(n-alkylamino)-3-methyl-1,4-naphthoquinone (1Na to 8Na) were synthesized using sodium metal as reductant at 0 °C in methanol. The formations of naphthosemiquinone radical in 1 to 6 have been confirmed from their EPR spectra. Polycrystalline powder X-band EPR spectra of 1 to 6 shows signals ∼2.0020 ± 0.0026 at 133 K. Anticancer activity of 2-(n-alkylamino)-3-methyl-1,4-naphthoquinone (1Na to 8Na) and one electron reduced forms have been evaluated against breast cancer (HeLa) cell line, 1 and 1Na showed promising anticancer activity
Silver and molybdenum disulfide nanoparticles synthesized in situ in dimethylformamide as dielectric for micro-electro discharge machining
No full textThe research focuses on the applicability of silver (Ag) and molybdenum disulfide (MOS2) nanoparticle synthesized in situ in dimethylformamide solution as dielectric material for micro-electro discharge machining. Ag nanoparticles (~120 nm size) and MOS2 nanoparticles (~20 nm size) were synthesized in dimethylformamide solution using a combination of nanoparticle solution synthesis routes. A setup for micro-electro discharge machining was developed in-house with an arrangement to generate spark at varying voltages. The setup was integrated with a precise linear height gauge to measure the spark gap during the experiments where Ag and MOS2 nanoparticles in dimethylformamide solution served as dielectric. The debris was collected and was characterized for each of the experiments. The feature size of the crater generated during the micro-electro discharge machining was also studied. The experiments were repeated with silver and MOS2 nanoparticle powder mixed with dimethylformamide as dielectric. It was observed that in situ prepared nanoparticles in dimethylformamide offered much better machining performance in terms of process stability, crater size and material removal rates. On use of in situ synthesized nanoparticle dielectric, the material removal rate increased by nearly two to three times whereas the spark gap increased by about two times
Studies on die filling of A356 Al alloy and development of a steering knuckle component using rheo pressure die casting system
No full textIn this study, a computational fluid dynamics (CFD) model is developed to investigate die filling of semi solid slurry as part of rheo pressure die casting (RPDC) system. The die filling cavity corresponds to that of an automobile steering knuckle, and the slurry is made of A356 aluminium alloy. The rheological model used in the CFD simulation is determined experimentally. The results obtained from present numerical model includes flow field of the slurry within the die cavity, viscosity evolution, solid fraction distribution, temperature and pressure distribution during solidification within cavity during die filling stage. The main objective of the study is to determine the gating arrangement, pouring temperature, and injection conditions for desirable microstructure and mechanical properties of the developed component. To study the effect of injection conditions on die filling capability of the said alloy slurry, five injection profiles are studied, with a variation in final injection velocity between 2–3.2 m/s. In order to corroborate the findings of the present study, microstructural morphology and structure-property correlation have been studied, primarily in the form of optical microscopy and macro hardness measurements, by obtaining samples from different locations of the solidified component
Thermal degradation of waste plastics under non-sweeping atmosphere: Part 1: Effect of temperature, product optimization, and degradation mechanism
No full textContinuous generation of plastic waste has prompted substantial research efforts in its utilization as a feedstock for energy generation. Pyrolysis has emerged as one of the best waste management technique for energy extraction from the plastic waste. The objective of this work is to investigate the effect of operating temperature on the liquid product yields in the pyrolysis process by non-isothermal heating. Non-catalytic thermal pyrolysis of waste polyethylene (PE) [high density polyethylene (HDPE)], waste polypropene (PP), waste polystyrene (PS), waste polyethylene terephthalate (PET) and mixed plastic waste (MPW) was carried out in a non-sweeping atmosphere in a semi-batch reactor at four different temperatures 450, 500, 550, and 600 °C. The minimum degradation temperature of the mixed and individual plastics was obtained using a thermogravimetric apparatus (TGA) at a heating rate of 20 °C/min. The TGA results show that all plastics degrade in a single step and the degradation temperatures of PS > PET > PP > HDPE, while mixed plastic degradation indicates two distinct degradation steps. Further, a waste polymer shows a lower degradation temperature than the virgin polymer. The degradation of HDPE is found to produce the maximum oil yield with minimum solid residue. The degradation of PET results in the highest amount of solid and benzoic acid as crystals and gas with no oil. Degradation of mixed plastic causes oil yield in the intermediate range of pyrolysis of individual plastic wastes. Overall, 500 °C is observed to be an optimum temperature for the recovery of low-density pyrolytic oil with the highest liquid yield. The degradation of PE and PP is found to be caused by random chain scission followed by inter and intramolecular hydrogen transfer. The degradation of PS occurs by side elimination or end chain scission followed by β-scission mechanism. The degradation of mix plastics results from random chain scission followed by β-scission mechanism. The effect of temperature on oil and gas recovery as well as recovery time was also assessed
Triazole-modified chitosan: a biomacromolecule as a new environmentally benign corrosion inhibitor for carbon steel in a hydrochloric acid solution
No full textIn this work, a new inhibitor, triazole modified chitosan, was synthesized for the first time following chemical modification of chitosan using 4-amino-5-methyl-1,2,4-triazole-3-thiol. The newly synthesized biopolymer (CS–AMT) was characterized using FTIR and NMR, and then it was evaluated as an inhibitor against corrosion of carbon steel in 1 M hydrochloric acid. The corrosion testing and evaluation were performed thoroughly employing the weight loss method, electrochemical measurements and surface analysis. A maximum corrosion inhibition efficiency of >95% was obtained at 200 mg L−1 concentration of inhibitor. The adsorption of inhibitor obeyed the Langmuir isotherm and showed physical and chemical adsorption. The electrochemical study via impedance analysis supported the adsorption of the inhibitor on the surface of carbon steel, and the potentiodynamic polarization indicated a mixed type of inhibitor behavior with cathodic predominance. To get a better insight on the interaction of inhibitor molecules with the metal surface, a detailed theoretical study was performed using DFT calculations, Fukui indices analysis and molecular dynamics (MD) simulation. The DFT study showed a lower energy gap of CS–AMT and the MD simulations showed an increased binding energy of CS–AMT compared to the parent chitosan and triazole moieties thereby supporting the experimental findings
Biodegradation of high concentration phenol using sugarcane bagasse immobilized Candida tropicalis PHB5 in a packed-bed column reactor
No full textBiodegradation of phenolic compounds in wastewater can be effectively carried out in packed bed reactors (PBRs) employing immobilized microorganisms. A low-cost, reusable immobilization matrix in PBR can provide economic advantages in large scale removal of high concentration phenol. In this study, we evaluated the efficiency and reusability of sugarcane bagasse (SCB) as a low-cost immobilization support for high strength phenol removal in recirculating upflow PBR. An isolated yeast Candida tropicalis PHB5 was immobilized onto the SCB support and packed into the reactor to assess phenol biodegradation at various influent flow rates. Scanning electron microscopy exhibited substantial cell attachment within the pith and onto the fibrous strand surface of the SCB support. The PBR showed 97% removal efficiency at the initial phenol concentration of 2400 mg L−1 and 4 mL min−1 flow rate within 54 h. Biodegradation kinetic studies revealed that the phenol biodegradation rate and biodegradation rate constant were dependent on the influent flow rate. A relatively higher rate of biodegradation (64.20 mg g−1 h−1) was found at a flow rate of 8 mL min−1, indicating rapid phenol removal in the PBR. Up to six successive batches (phenol removal >94%) were successfully applied in the PBR using an initial phenol concentration of 400–2400 mg L−1 at a flow rate of 4 mL min−1 indicating the reusability of the PBR system. The SCB-immobilized C. tropicalis could be employed as a cost-effective packing material for removal of high strength phenolic compounds in real scale PBR
Weak interactions: The architect behind the structural diversity of coordination polymer
No full textThe design and development of crystal structure is of immense significance in the realm of supramolecular chemistry. Each crystal is unique of its kind and distinguishes the different arrangement of atoms. However the assembly of these atoms is controlled by its geometry and chemical properties. This kind of structural diversity is widely observed in coordination polymers. In structural arrangement, building blocks play a major role towards architecting the different dimensionalities and accordingly such arrangements possess diverse applicability. Currently various architectures are developed with a wide variation in the building blocks. All the elements existing within the crystal structure works in union by supramolecular non-covalent interactions. The overall stability and diversity in the architecture widely depends on these weak non-covalent interactions which finally lead to different physical properties. Among the weak non-covalent interactions, hydrogen bonding, π-π interactions, Vander Waals attraction are implicitly predominating in developing individual architecture. The spatial orientation of the individual atoms or groups is significant for the development of weak interaction within the structure. The chemical environment and spatial arrangement of the building blocks also govern the distribution of the atoms or groups in the constructional arrangement. Binding arrangement between the building blocks define the diverse dimensionality or different nets of the coordination polymer. Sometimes the development of varying structure depends on the factors including growing environment like pH, solvent, counter ion of the coordination polymer etc. An in-depth introduction of the various building blocks and its importance in construction of different architecture has been discussed in this review. But the primary focus of the present review is to establish and emphasize the role of weak interactions towards architecting different coordination polymer. Our aim is to provide an obvious idea about the correlation between weak non-covalent interaction inside the architecture and the different structural diversity of coordination polymer
Review on electron beam based additive manufacturing
No full textPurpose
Electron beam-based additive manufacturing (EBAM) is an emerging technology to produce metal parts layer-by-layer. The purpose of this paper is to systematically address the research and development carried out for this technology, up till now.
Design/methodology/approach
This paper identifies several aspects of research and development in EBAM.
Findings
Electron beam has several unique advantages such as high scanning speed, energy efficiency, versatility for several materials and better part integrity because of a vacuum working environment.
Originality/value
This paper provides information on different aspects of EBAM with the current status and future scope