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Effect of gallium, aluminium, and chromium on silica supported V-Mg-O catalysts during oxidative dehydrogenation of propane: Kinetic study

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Journal of Natural Gas Chemistry 2008年第3期17卷 256-263页

作者： B.Ravi kumar rajeev kumar Department of Chemical Engineering Indian Institute of Technology

The oxidative dehydrogenation （ODH） of propane was conducted on gallium, aluminum, and chromium doped Si30VMgO catalysts. On doping, the concentrations of the phases responsible for the activity and selectivity increased in their concentrations. The reaction studies were conducted in a tubular steel reactor at temperatures of 753, 783, 813, and 843 K and atmospheric pressure. The total flow rates of the feed were chosen as 30, 40, 50, and 60 ml/min. The propane to oxygen ratios were chosen at 1 ： 1, 2 ： 1, and 3 ： 1, respectively. The effect of various dopants on the activity and selectivity of the catalysts was studied. Deactivation studies were conducted over all the catalysts. The kinetic data were analyzed in terms of power law models and Langmuir-Hinshelwood （LH） models. The kinetic data results were analyzed by comparing the effect of dopants. Statistical model discrimination was done for the proposed models. AIC and BIC criteria were used for discrimination of the models.

关键词： oxidative dehydrogenation propane gallium aluminum chromium kinetic

Propagation of wave at the boundary surface of transversely isotropic thermoelastic material with voids and isotropic elastic half-space

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Applied Mathematics and Mechanics(English Edition) 2010年第9期31卷 1153-1172页

作者： Rajneesh kumar rajeev kumar Department of Mathematics Kurukshetra UniversityKurukshetra 136119India

The purpose of this research is to study the effect of voids on the surface wave propagation in a layer of a transversely isotropic thermoelastic material with voids lying over an isotropic elastic half-space. The frequency equation is derived after developing a mathematical model for welded and smooth contact boundary conditions. The dispersion curves giving the phase velocity and attenuation coefficient via wave number are plotted graphically to depict the effects of voids and anisotropy for welded contact boundary conditions. The specific loss and amplitudes of the volume fraction field, the normal stress, and the temperature change for welded contact are obtained and shown graphically for a particular model to depict the voids and anisotropy effects. Some special cases are also deduced from the present investigation.

关键词： propagation of wave transverse isotropy thermoelastic with voids isotropic elastic half-spaze phase velocity attenuation coefficient

Surface Modification Aspects for Improving Biomedical Properties in Implants:A Review

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 213-241页

作者： J.Sharath kumar Rakesh kumar rajeev Verma Industrial and Production Department Dr B R Ambedkar National Institute of Technology JalandharJalandharPunjab144008India

The primary focus during surgery is to ensure successful implantation by achieving long-term and stable fixation of *** surgery is now more focused on the development of novel biomaterials intended to improve implant *** obtain a better understanding of metal implants,this article investigated the causes of material failures in certain cases and analysed a few case *** interaction between the implant and bone tissue was a crucial aspect of successful implantation,and this study explored the factors influencing this interaction as well as ways to improve *** modern approaches used for modifying implant surfaces were systematically illustrated and briefly *** spray coatings were often favoured because of their wide range of coating materials,but other substantial surface modifications(such as friction stir processing and laser surface texturing)were also used for a selection of ***,implant surfaces with desirable features,such as biocompatibility,antibacterial properties,corrosion resistance,and wear resistance,were essential for optimising implant *** systematic review's main aim is to provide exhaustive reference information and a broad overview to advance the production and design of orthopaedic implants.

关键词： Biomaterials Surface treatments Thermal spray coatings Antibacterial Biocompatibility Corrosion resistance Wear resistance

Solution and Thermodynamic Studies on Binary and Ternary Complexes of Lanthanides

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Journal of Rare Earths 2005年第4期23卷 389-396页

作者： rajeev kumar Udai P Singh Department of Chemistry Indian Institute of Technology Roorkee Roorkee-247667 IndiaDepartment of Chemistry Indian Institute of Technology Roorkee Roorkee-247667 India

The interactions of La（ Ⅲ ）, Pr（ Ⅲ ）, Nd（ Ⅲ ）, Sm（ Ⅲ ）, Eu（Ⅲ）, Gd（ Ⅲ ）, Dy（ Ⅲ ）, and Yb（ Ⅲ ） with cytosine, 5-bromocytosine, 5-azacytosine and 5-flurocytosine as primary ligands （L） and guanine （A） as secondary ligand for both binary （ 1 ： 1 ） as well as ternary （ 1 ： 1 ： 1 ） systems were investigated by potentiometric equilibrium measurements at 25, 35 and 45 ℃ in aqueous solution （ionic strength, μ = 0.1 mol·dm^-3 NaNO3）. The stability constants of the binary （ 1 ： 1 ） and ternary （ 1 ： 1 ： 1 ） metal-ligand complexes follow the following order La 〈 Pr 〈 Nd 〈 Sm 〈 Eu 〉 Gd 〈 Dy 〉 Yb. Results also indicate that the ternary lanthanide complexes of La（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Dy（Ⅲ）, and Yb（ Ⅲ ） are more stable than corresponding binary lanthanide complexes. The enthalpy （△Hf^o） and entropy （△Sf^o） changes for the formation of binary and ternary complexes were calculated from temperature coefficient data. The △△Sf^o values are positive for all the metal ligand systems. The negative △△Hf^o values indicate the extra stability of the ternary complexes by the exothermic enthalpy changes （△△Sf^o = △TSf^o - △BSf^o and △△Hf^o = △THf^o - △BHf^o where △TSf^o, △THf^o and △BSf^o, △BHf^o are the entropy and enthalpy values associated with the ternary and binary complexes, respectively）. It was also proposed that the guanine is bonded to metal ions through N1/C6 = O and N7 whereas cytosine and its derivatives are bonded through N3 atoms in ternary complexes.

关键词： lanthanide solution studies cytosine thermodynamic properties rare earths

Translocator protein and neurodegeneration: insights from Alzheimer’s disease

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Neural Regeneration Research 2025年第4期20卷 1090-1091页

作者： Arpit kumar Pradhan Rainer Rupprecht Gerhard Rammes Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München Klinikum rechts der IsarMunichGermany Graduate School of Systemic Neurosciences Ludwig-Maximilians-Universität MünchenMartinsriedGermany Department of Psychiatry and Psychotherapy University RegensburgRegensburgGermany

The 18 kDa translocator protein(TSPO)located on the outer mitochondrial membrane regulates several key cellular processes including mitochondrial homeostasis,cholesterol transport,apoptosis,cell proliferation,and maintenance of mitochondrial health(Rupprecht et al.,2022,2023).TSPO is expressed in both peripheral organs and the central nervous system,with a more pronounced expression in tissues that produce *** main reason why TSPO has garnered so much attention is because it plays a key role in neurosteroidogenesis by transferring cholesterol from the outer to the inner mitochondrial membrane,which is the rate-limiting step in neurosteroid synthesis.A cholesterol-recognizing amino acid consensus domain has been identified in the cytosolic C terminus of the TSPO protein by both in vitro and site-directed mutagenesis experiments(Li et al.,2001).However,the role of TSPO in the process of neurosteroid synthesis has been challenged by several studies,particularly TSPO knockout models,which suggest that TSPO removal does not affect the phenotype or the system’s viability(Tu et al.,2014).However,ligands targeting TSPO have been shown to enhance levels of neurosteroids which suggests that neurosteroidogenesis is one of the major functional roles mediated by the TSPO protein.

关键词： cholesterol organs

An update on the role of medical treatment including antioxidant therapy in varicocele

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Asian Journal of Andrology 2016年第2期18卷 222-228,J0004页

作者： Harshit Garg rajeev kumar Department of Urology All india Institute of Medical Sciences New Delhi India

Varicocele-associated male infertility has classically been managed using surgery or assisted reproductive techniques. With increasing evidence of oxidative stress as a pathophysiological factor in varicocele-associated infertility, medical therapy especially antioxidants might become a treatment option with lower risks. We reviewed the existing literature on the role of various medical agents in the management of male infertility attributed to varicoceles. Medical therapy is typically evaluated in three different situations such as （a） comparison of two drugs or one drug with placebo, （b） comparison of drugs versus surgery, and （c） comparison of drugs as adjuvant therapy with surgery versus drug therapy alone. Due to heterogeneity of data and lack of well-conducted studies, there is insufficient data to recommend routine use of medical therapy for men with varicocele-associated infertility and surgery remains the treatment of choice. Pregnancy and live birth rates are usually not reported in most studies and mere improvement in sperm parameters or antioxidant capacity is insufficient to support its routine use. Antioxidant therapy is a potential option due to its theoretical benefit, data from preclinical studies, and lack of major side effects. Adjuvant therapy with antioxidants after surgical repair of varicocele may improve the outcome and is a potential area for further research.

关键词： antioxidant therapy drug therapy male infertility varicocele

Effect of processing parameters on the electromagnetic radiation emission during plastic deformation and crack propagation in copper-zinc alloys

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1800-1809页

作者： kumar rajeev MISRA Ashok Department of Mechanical Engineering Birla Institute of Technology Mesra 835215 Ranchi India

This paper presents some investigations on the effect of processing parameters on the emission of electromagnetic radiation （EMR） during plastic deformation and crack propagation in copper-zinc alloys. Timing of the EMR emissions, maximum stress during crack instability, stress-intensity factor, elastic strain energy release rate, maximum EMR amplitude, RMS value of EMR amplitude, EMR frequency and electromagnetic energy release rate were analysed for the effect of rolling directions at different percentage of zinc content in Cu-Zn alloy specimens. The same parameters were also analysed for 68-32 Cu-Zn alloy specimens at different annealing temperatures and at different angles 0, to the rolling direction. EMR emissions are observed to be highly anisotropic in nature. At θ=45° to 60°, marked changes in mechanical and electromagnetic parameters were observed. Specimens annealed at 500℃, just above the recrystallization temperature, and at 700℃, when grain-size growth is rapid, EMR responses have been found to have well-defined patterns.

关键词： Radiation Plastic deformation Rolling direction Annealing Fracture

UAV Clustering Scheme for FANETs using Elbow-Hybrid Metaheuristic Techniques

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Computer Systems Science & Engineering 2021年第9期38卷 321-337页

作者： Kundan kumar rajeev Arya Department of Electronics and Communication Engineering National Institute of Technology PatnaPatna800005India

Great strides have been made to realistically deploy multiple Unmanned Aerial Vehicles(UAVs)within the commercial domain,which demands a proper coordination and reliable communication among the *** suffer from limited time of *** techniques suffer from high delay,low throughput,and early node death due to aerial topology of UAV *** deal with these issues,this paper proposes a UAV parameter vector which considers node energy,channel state information and mobility of *** intelligently estimating the proposed parameter,the state of UAV can be predicted ***,efficient clustering may be achieved by using suitable metaheuristic *** the current work,Elbow method has been used to determine optimal cluster count in the deployed *** proposed UAV parameter vector is then integrated into two popular hybrid metaheuristic algorithms,namely,water cycle-moth flame optimization(WCMFO)and Grey Wolf-Particle Swarm optimization(GWPSO),thereby enhancing the lifespan of the system.A methodology based on the holistic approach of parameter and signal formulation,estimation model for intelligent clustering,and statistical parameters for performance analysis is carried out by the energy consumption of the network and the alive node *** simulations are run to demonstrate node density variations to validate the theoretical developments for various proportions of network system *** proposed method presents significant improvement over conventional stateof-the-art methods.

关键词： Clustering elbow method hybrid UAVs FANETs energy consumption

Battery energy storage-based system damping controller for alleviating sub-synchronous oscillations in a DFIG-based wind power plant

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Protection and Control of Modern Power Systems 2023年第2期8卷 260-277页

作者： Neevatika Verma Narendra kumar rajeev kumar Department of Electrical Engineering Delhi Technological UniversityNew DelhiIndia Electrical Engineering Department Jamia Millia IslamiaNew DelhiIndia Electrical and Electronics Engineering Department KIET Group of InstitutionsGhaziabadIndia

This paper presents the issue of the Sub-synchronous resonance(SSR)phenomenon in a series compensated DFIG-based wind power plant and its alleviation using a Battery Energy Storage-based Damping Controller(BESSDCL).A supplementary damping signal is developed considering the angular speed deviation and is incorporated into the BESS control ***-area Measurement System data is used to determine the angular speed deviation.A lin-earized system model is developed to perform eigenvalue analysis,and to detect and examine unstable SSR *** variation of wind speed and three-phase fault are also taken into consideration to validate the robustness of the *** further verify the efficacy of the proposed damping controller,time-domain simulations are performed using MATLAB/*** application of the proposed BESSDCL stabilizes all the unstable system modes effectively at wind speeds of 7 m/s,9 m/s,and 11 m/s,and at 40%,50%,and 60%series compensation levels,as well three-phase fault conditions.

关键词： Battery energy storage system Damping controller Doubly-fed induction generator(DFIG) Series