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Effects of Main-chain and Chain-ends on the Organogelation of Stearoyl Appended Pendant Valine Based Polymers

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Chinese Journal of Polymer Science 2019年第9期37卷 903-911页

作者： Mridula nandi Swagata Pan Dipannita Ghosh Priyadarsi De Polymer research Centre and Centre for Advanced Functional Materials Department of Chemical Sciences Indian Institute of Science Education and Research Kolkata

In this work, we investigated the effect of hydrophobic interactions between the polymeric backbone and chain-end groups on the self-assembly pathway of stearoyl appended side-chain valine（Val）-based poly（methacrylate/acrylate） homopolymers in different organic hydrocarbons. Gelation studies conducted revealed that while polymers with polyacrylate as backbone induces gelation in several organic hydrocarbons, polymers with polymethacrylate in the main-chain significantly hinders macroscopic gelation. Morphology of the organogels was analysed by field emission scanning electron microscopy（FESEM）, and mechanical strengths of the organogels were determined by rheological measurements. reversible addition-fragmentation chain transfer（rAFT） polymerization chain transfer agents（CTA）s, [r1―S―C=（S）―S―r2] with different ―r1 and ―r2 groups, have been employed to study the effect of structural variation at the chain-end on macroscopic assembly mechanism. We found that the additional interactions between terminal groups via hydrogenbonding or π-π stacking interactions or both help to build up the self-assembly pathway and thereby produces mechanically stable organogels.

关键词： Organogelation Hydrophobic interactions Poly(methacrylate/acrylate) backbone rAFT polymerization Self-assembly

Electric discharge phenomenon in dielectric and electrolyte medium

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Advances in Manufacturing 2018年第4期6卷 457-464页

作者： Mukesh Kumar Sindhu Debasish nandi Indrajit Basak Department of Mechanical Engineering. NIT Durgapur. Durgapur 713209. India Department of Mechanical Engineering JIS College of Engineering Kalyani 741235 India

Electric discharge is a common tool nowadays for machining of materials. It may be through a liquid medium or through air. Any metals, hard alloys, and nonmetals can be machined using the energy of electric discharge. In electric discharge machining (EDM), the discharge occurs between two electrodes through a liquid medium and it is applicable only for electrically con ducting materials and alloys. In electrochemical discharge machining (ECDM), the medium is an aqueous electrolyte and it is of two types. In the first type, the discharge occurs between two electrodes. One of the electrodes is the workpiece, and the other is the tool. In the second type, the discharge occurs between one electrode and an electrolyte. It is used for electrically nonconducting materials and the discharge energy is utilized maintaining the nonconducting workpiece in proximity of the discharge. All these electrical discharges are transient phenomena and do not result in a stable discharge in the form of arc. The output parameters depend on the discharge energy that requires precise control to maintain the accuracy of the machining. For micromachining, the control of the discharge is paramount both in terms of energy and pattern. Using various shaped tools, machining media with additives, different types of applied potentials, and supporting mechanical motions are some of the attempts made to improve the machining output. Optimization of these parameters for machining particular materials (or alloys) is a popular field of research. The present work is directed toward the investigation of discharge initiation and development by analyzing the cell current and discharge voltage relationship for both EDM and ECDM. The rectangular direct current (DC) pulse with different frequencies and the duty factor (on-off time ratio) are used for investigation. Observations on the voltage-current relationship are made for the external potential prior to discharge at discharge and above the discharge potenti

关键词： Electric discharge Electric discharge machining (EDM) Electrochemical discharge machining (ECDM) Pulsed direct current (DC) Duty factor

revisiting Pauwels' classification of femoral neck fractures

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World Journal of Orthopedics 2021年第11期12卷 811-815页

作者： Sumon nandi Orthopaedic Surgery Department University of Maryland School of MedicineBaltimoreMD 21201United States

Pauwels’femoral neck fracture classification is based on the biomechanical principle that shear stress and varus force increase along more vertically oriented fractures,resulting in higher risk of fracture displacement and ultimately *** principle continues to guide construct selection for femoral neck fracture internal fixation and is the foundation for treating non-union with valgus ***,with poor inter-and intra-rater reliability,dated treatment recommendations,and unreliable prognostic value,the Pauwels classification cannot be directly applied in its entirety to the management of femoral neck fractures in modern practice.

关键词： Pauwels Fracture Femoral neck Internal fixation Arthroplasty

A generic method for rock mass classification

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Journal of rock Mechanics and Geotechnical Engineering 2018年第1期10卷 102-116页

作者： Vitthal M.Khatik Arup Kr.nandi Department of Mechanical Engineering Indian Institute of TechnologyKanpur208016India Engineering Design Group CSIR-Central Mechanical Engineering Research InstituteMG AvenueDurgapur713209India

rock mass classification(rMC) is of critical importance in support design and applications to mining,tunneling and other underground excavations. Although a number of techniques are available, there exists an uncertainty in application to complex underground works. In the present work, a generic rock mass rating(GrMr) system is developed. The proposed GrMr system refers to as most commonly used techniques, and two rock load equations are suggested in terms of GrMr, which are based on the fact that whether all the rock parameters considered by the system have an influence or only few of them are influencing. The GrMr method has been validated with the data obtained from three underground coal mines in India. Then, a semi-empirical model is developed for the GrMr method using artificial neural network(ANN), and it is validated by a comparative analysis of ANN model results with that by analytical GrMr method.

关键词： rock mass classification(rMC) Generic system rock load Mathematical model Artificial neural network(ANN)

In vitro and in vivo degradability,biocompatibility and antimicrobial characteristics of Cu added iron-manganese alloy

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Journal of Materials Science & Technology 2021年第25期84卷 159-172页

作者： Santanu Mandal Vijay Kishore Madhuparna Bose Samit Kumar.nandi Mangal ro Department of Metallurgical and Materials Engineering Indian Institute of Technology-KharagpurKharagpur 721302India Department of Veterinary Surgery&radiology West Bengal University of Animal&Fishery SciencesKolkata 700037India Department of Biotechnology Indian Institute of TechnologyKharagpur 721302India

In recent years,iron(Fe)based degradable metal is explored as an alternative to permanent fracture fixation *** the present work,copper(Cu)is added in Fe-Mn system to enhance the degradation rate and antimicrobial ***-Mn-x Cu(x=0.9,5 and 10 wt.%)alloys are prepared by the meltingcasting-forging *** analysis confirms austenite phase stabilization due to the presence of Mn and *** predicted by Thermo-Calc calculations,Cu rich phase precipitations are noticed along the austenite grain *** behaviours of Cu added Fe-Mn alloys are investigated through static immersion and electrochemical polarization where enhanced degradation is found for higher Cu added *** challenged against *** bacteria,the Fe-Mn-Cu alloy media extract shows a significant bactericidal effect compare to the base *** vitro cytocompatibility studies,as determined using MG63 and MC3T3-E1 cell lines,indicate increased cell density as a function of time for all the *** implanted in rabbit femur,the newly developed alloy does not show any kind of tissue necrosis around the *** osteogenesis and higher new bone formation are observed with Fe-Mn-10 Cu alloy as evident from micro-computed tomography(μ-CT)and fluorochrome labelling.

关键词： Iron-manganese alloy Degradable metal In vitro Micro-CT

混合现实全息影像技术在多种临床常用穿刺操作教学中的应用

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卫生职业教育 2024年第8期42卷 75-79页

作者：徐艺瑄魏星包楠迪解放军总医院第二医学中心北京100853 解放军总医院第六医学中心心血管病医学部北京100037

为评价混合现实全息影像技术在实习医师胸腔、腹腔、腰椎、骨髓穿刺操作教学中的应用价值,以解放军总医院2023年招收的实习医师为研究对象,随机分为实验组和对照组,实验组采用混合现实全息影像技术教学方法,对照组采用传统模具教学方法... 详细信息

为评价混合现实全息影像技术在实习医师胸腔、腹腔、腰椎、骨髓穿刺操作教学中的应用价值,以解放军总医院2023年招收的实习医师为研究对象,随机分为实验组和对照组,实验组采用混合现实全息影像技术教学方法,对照组采用传统模具教学方法,进行胸腔、腹腔、腰椎、骨髓穿刺操作教学,并通过考试及教学满意度问卷调查比较两组教学效果的差异。实践表明,混合现实全息影像技术教学方法在胸腔、腹腔、腰椎、骨髓穿刺操作教学中应用,收到满意的教学效果,且实习医师教学满意度高。

关键词：混合现实技术全息影像穿刺操作教学

Effect of weathering on physico-chemical properties and combustion behavior of an Indian thermal coal

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International Journal of Coal Science & Technology 2019年第1期6卷 51-62页

作者： Subhajit Aich Barun Kumar.nandi Sumantra Bhattacharya Department of Fuel and Mineral Engineering Indian Institute of Technology (Indian School of Mines)Dhanbad Dhanbad Jharkhand 826004India

An open air stockpile of conical shape was formed with 3.5 m base diameter and 5 m height using 500 tons of -200 mm size rOM thermal coal on a concrete floor. Coal sample from the stockpile were collected at 30 days interval for analysis of various chemical properties like;proximate analysis, ultimate analysis, gross calorific value (GCV) and various combustion related properties such as ignition temperature, peak temperature, burnout temperature, maximum combustion rate, ignition index, burnout index, combustion performance index and combustion rate intensity index. Experimental results show that, due to weathering of coal fixed carbon decreased from 35.6% to 19.9%, elemental carb on (C) decreased from 46.6% to 28.6%, hydrogen (H) decreased from 3.3% to 2.9% and GCV decreased by up to 55% of original value during 330 days of storage of coal in an open atmosphere. Ash con tent of coal increased form 29.2% to 46.6% due to loss of combustibles. Sulfur (S) of coal was found to get increased from 0.33% to 1.08% during storage. The activation energy of coal combustion increased from 22 kJ/mol to 54 kJ/mol. Variation in combustion parameters signifies that weathering has significant negative impact on coal combustion properties as coal become difficult to ignite.

关键词： Weathering of coal TGA-DTG Combustibles Coal combustion Activation energy

Elevated basal intestinal mucosal cytokine levels in asymptomatic first-degree relatives of patients with Crohn's disease

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World Journal of Gastroenterology 2000年第1期6卷 49-52页

作者： Indaram AVK nandi S Weissman S Lam S Bailey B Blumstein M Greenberg r Bank S Division of Gastroenterology Long Island Jewish Medical CenterAlbert Einstein College of MedicineNew YorkUSA

AIM To determine levels of cytokines incolonic mucosa of asymptomatic first degreerelatives of Crohn’s disease *** Cytokines(Interleukin(IL)1-Beta,IL-2,IL-5 and IL-8)were measured using ELISAin biopsy samples of normal looking colonicmucosa of first degree relatives of Crohn’sdisease patients(n = 9)and from normalcontrols(n = 10)with no family history ofCrohn’s *** Asymptomatic first degree relativesof patients with Crohn’s disease had significantlyhigher levels of basal intestinal mucosalcytokines(IL-2,IL-5 and IL-8)than *** these increased cytokinelevels serve as phenotypic markers for a geneticpredisposition to developing Crohns diseaselater on,or whether they indicate early(pre-clinical)damage has yet to be further *** Asymptomatic first degreerelatives of Crohn’s disease patients have higherlevels of cytokines in their normal-lookingintestinal mucosa compared to normal controls,This supports the hypothesis that increasedcytokines may be a cause or an early event inthe inflammatory cascade of Crohns disease andare not merely a result of the inflammatoryprocess.

关键词： Subject headings crohns disease cytokine/analysis intestinal mucosa

relationship between proximate analysis parameters and combustion behaviour of high ash Indian coal

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International Journal of Coal Science & Technology 2020年第4期7卷 766-777页

作者： Subhajit Aich Dibyajyoti Behera Barun Kumar.nandi Sumantra Bhattacharya Department of Fuel Minerals and Metallurgical Engineering Indian Institute of Technology(Indian School of Mines)DhanbadDhanbadJharkhand 826004India

This work presents the analysis of combustion characteristics of high ash Indian coal(28%-40%)collected from different mines of Singaurali coalfield,*** the coal samples were characterized by proximate and gross calorific value *** performance of the coals were characterised using thermo-gravimetric analysis to identify the burning profile of individual *** combustion kinetic parameters such as ignition temperature,peak temperature and burnout temperature,ignition index and burnout index,combustion performance index plus rate and intensity index of combustion process,activation energy were determined to analyse the combustion behaviour of *** all these combustion properties were compared with the volatile matter,ash,fixed carbon and fuel ratio of each *** analysis shows that with increase in ash content,combustion performance initially increases and later ***,coal with(25±1.75)%volatile matter,20%-35%ash and fuel ratio 1.4-1.5 were found to be optimum for coal combustion.

关键词： TGA-DTG Proximate analysis Combustion kinetics Activation energy Burning profile