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不同冲击冷却结构对旋转效应的敏感性

工程热物理学报 2016年第1期37卷 37-41页

作者：杨力 kartikeya tyagi 任静 Srinath Ekkad 蒋洪德清华大学热能工程系北京100084 弗吉尼亚理工学院

本文针对多排孔冲击和通道之间倾斜冲击结构进行了旋转条件下数值模拟研究,通过流场和传热分析了不同结构和不同部位对旋转科氏力和离心力的敏感性。冲击射流动量较大,旋转数小,且旋转二次流发展空间不足,导致多排孔冲击结构对旋转的敏... 详细信息

本文针对多排孔冲击和通道之间倾斜冲击结构进行了旋转条件下数值模拟研究,通过流场和传热分析了不同结构和不同部位对旋转科氏力和离心力的敏感性。冲击射流动量较大,旋转数小,且旋转二次流发展空间不足,导致多排孔冲击结构对旋转的敏感性降低。通道之间双排倾斜冲击结构对旋转的影响比多排孔冲击结构敏感,主要体现在下游前缘的冲击靶面上。根据旋转数大小采用非对称的射流结构可以优化传热分布。

关键词：旋转冲击冷却科氏力

Synthesis, characterization and biocidal properties of platinum metal complexes derived from 2,6-diacetylpyridine (bis thiosemicarbazone)

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Open Journal of Inorganic Chemistry 2012年第3期2卷 41-48页

作者： Monika tyagi Sulekh Chandra Department of Chemistry Zakir Husain Delhi College (University of Delhi) J. L. N. Marg New Delhi - 110 002 India

The coordination compounds of PdII, PtII, RhIII and IrIII metal ions with a Schiff base ligand (L) i.e. 2,6- diacetylpyridine bis(thiosemicarbazone) have been synthesized and characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, IR, NMR and electronic spectral studies. On the basis of molar conductance and elemental analyses the complexes were found to have composition [M(L)]Cl2 and [M’(L)Cl]Cl2, where M = Pd(II), Pt(II) and M’ = Rh(III), Ir(III). The spectral studies reveal that the complexes possess monomeric composition. Complexes of PdII and PtII were found to have four coordinated square planar geometry whereas the complexes of RhIII and IrIII posses six coordinated octahedral geometry. The ligand field parameters were calculated using various energy level diagrams. In vitro synthesized compounds and metal salts have been tested against some species of plant pathogenic fungi and bacteria in order to assess their antimicrobial properties.

关键词： Schiff Base Platinum Metal Complexes Spectral Studies Biological Screening

Study of Eppler 423 Airfoil with Gurney Flap and Vortex Generators

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Advances in Aerospace Science and Technology 2020年第1期5卷 1-19页

作者： Sushil Chandra Rajan tyagi Aerospace Engineering Department IIT Bombay Mumbai India

In the past extensive research has been carried out, to study the effect of Gurney flap (GF) on symmetric and cambered airfoil for its usage in low Reynolds number regime. Use of GF at the trailing edge of the airfoil enhances the lift due to increase in the effective camber of the airfoil, which in turn improves the aerodynamic efficiency i.e. Cl/Cd. In the present study, Eppler 423 airfoil is used to first understand the aerodynamics of such a highly cambered airfoil and later GF of various sizes were added on it to understand the change in flow dynamics achieved by adding the GF and their impact on aerodynamic parameters such as Cl, Cd and Cl/Cd. Eppler 423 being a highly cambered airfoil produces high lift coefficient and smoother stall and by adding the GF of various sizes the performance of Eppler 423 improves tremendously and reason for this enhanced performance and effect of size of GF are presented in this paper. Vortex Generators (VG) generate counter rotating vortices that allow the flow to remain attached even at high angles of atta.k. Also, effect of adding VG at the leading edge of Eppler 423 aerofoil is presented in this paper. At last, results obtained from combination of VG at leading edge and GF at trailing edge on Eppler 423 aerofoil are discussed at length.

关键词： Eppler 423 Airfoil Gurney Flap Vortex Generators Aerodynamic Efficiency Stall

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不可逆布雷顿制冷循环的性能优化

低温工程 2004年第3期 41-44,52页

作者：林比宏 S.k.tyagi 陈金灿厦门大学物理系泉州师范学院物理系泉州362000

基于不可逆布雷顿制冷循环模型 ,导出循环制冷率和性能系数之间优化关系所应满足的方程 ,利用数值解 ,研究内不可逆性和传热不可逆性对优化性能的影响。讨论了循环的各种优化性能 ,所得结果对实际制冷系统的优化设计有一定的指导意义。

关键词：布雷顿制冷循环制冷率性能系数优化关系优化性能热力学

Biotoxicity of CdS/CdSe Core-Shell Nano-Structures

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Advances in Nanoparticles 2016年第1期5卷 1-8页

作者： Sreenu Bhanoth Anuraj S. kshirsagar Pawan k. khanna a.k.iti tyagi Anita.k. Verma Nanochemistry R & D Lab Department of Applied Chemistry Defence Institute of Advanced Technology (DIAT) Ministry of Defence Government of India Girinagar Pune-411 021 India Nano Bio-Tech Lab Department of Zoology Kirorimal College University of Delhi Delhi India

The cytotoxicity of hydrophobic QDs CdS/CdSe was tested assigning MTT assay on Human Embryonic kidney cells (HEk-293), breast cancer cells (MCF-7) and Enrichlish Ascitices Cells (EAC). Approximately 65% bio-toxicity was observed in MCF-7 for the core-shell QDs. These QDs may also find effective applications in other optoelectronic devices. CdS/CdSe core-shell hetrostructure quantum dots (QDs) were generated by chemical reaction between the respective chalcogens and cadmium metal salt. Sulphur powder was utilized for CdS core preparation while selenium was extracted from an organoselenium compound to impart CdSe shell layer at a temperature between 150℃ - 200℃. So-prepared core-shell QDs showed good optical properties. The particle size was found to be in the range of 3 - 4 nm with spherical morphology and cubic crystal structure.

关键词： Quantum Dots Metal Chalcogenides Bio-Toxicity Cell Lines

Developing Strong and Hybrid Formulation for the Single Stage Single Period Multi Commodity Warehouse Location Problem: Theoretical Framework and Empirical Investigation

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American Journal of Operations Research 2015年第3期5卷 112-128页

作者： R. R. k. Sharma Parag tyagi Vimal kumar Ajay Jha Department of Industrial & Management Engineering IIT Kanpur India

We note that the Single Stage Single Period Multi Commodity Warehouse Location Problem (SSSPMCWLP) has been first attempted by Geoffrion and Graves [1], and that they use the weak formulation (in context of contribution of this paper). We give for the first time “strong” formulation of SSSPMCWLP. We notice advantages of strong formulation over weak formulation in terms of better bounds for yielding efficient Branch and Bound solutions. However, the computation time of “strong” formulation was discovered to be higher than that of the “weak” formulation, which was a major drawba.k.in solving large size problems. To overcome this, we develop the hybrid strong formulation by adding only a few most promising demand and supply side strong constraints to the weak formulation of SSSPMCWLP. So, the formulations developed were put to test on various large size problems. Hybrid formulation is able to give better bound than the weak and takes much less CPU time than the strong formulation. So, a.k.nd of trade off is achieved allowing efficiently solving large sized SSSPMCWLP in real times using hybrid formulation.

关键词： SSUWLP SSSPMCWLP Strong and Weak Constraints Hybrid Formulation RMIP

Effect of micro-environmental factors on natural regeneration of Sal (Shorea robusta)

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Journal of Forestry Research 2011年第4期22卷 543-550页

作者： J. V. tyagi Rakesh kumar S. L. Srivastava R. D. Singh National Institute of Hydrology Jalvigyan Bhawan Roorkee - 247 667Uttarakhand India

factors viz., soil moisture and light in- tensity are important factors that affect natural regeneration in forests. These factors vary spatially depending on the overhead canopy density of the forest. The present study focused on studying the effect of variation of soil moisture and light intensity on natural regeneration of sal species （Shorea robusta） under different micro-environments due to overhead canopy of varying forest density. Experimental plots of 40m× 40m size were laid under different overhead canopy densities in a small sal forested watershed in the foot hills of Himalayas in Nainital District of Uttarakhand State, India. The plots were monitored on a long term basis for soil moisture at multi depths, light intensity and natural regeneration of sal. The results of the study revealed that the natural regeneration was highest under C1 （up to-0.30） canopy followed by C2 （0.30-0.50）, and C3 （0.50-0.70） canopies. The C3 canopy showed the dying ba.k.of sal shoots over 4 years of study. The highest R2 value of linear regression between incremental score of plot regeneration and average soil moisture content was obtained as 0.156 for average soil moisture content during months at 100 cm depth. The R2 value between incremental score of plot regeneration and annual average light intensity was obtained as 0.688 which indicated that the regeneration is largely dependent on the light intensity conditions during the year. The multiple linear regression analysis between the incremental score of regeneration and the average light intensity and average soil moisture content revealed that that about 80% of variation in regeneration is explained by both the factors.

关键词： Natural regeneration sal canopy density soil moisture,light intensity

Experimental study of laser cladding process and prediction of process parameters by artificial neural network(ANN)

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Journal of Central South University 2022年第10期29卷 3489-3502页

作者： Rashi tyagi Shakti kUMAR Mohammad Shahid RAZA Ashutosh TRIPATHI Alok kumar DAS University Centre for Research and Development Chandigarh UniversityMohali-140413India Department of Mechanical Engineering Chandigarh UniversityMohali-140413India Department of Mechanical Engineering IIT(ISM)Dhanbad-826004India Department of Mechanical Engineering IIT KharagpurIndia

Laser cladding of powder mixture of TiN and SS304 is carried out on an SS304 substrate with the help of fibre *** experiments are performed on SS304,as per the Taguchi orthogonal array(L^(16))by different combinations of controllable parameters(microhardness and clad thickness).The microhardness and clad thickness are recorded at all the experimental runs and studied using Taguchi S/N ratio and the optimum controllable parametric combination is ***,an artificial neural network(ANN)identifies different sets of optimal combinations from Taguchi method but they both got almost the same clad thickness and hardness *** micro-hardness of cladded layer is found to be6.22 times(HV_(0.5)752)the SS304 hardness(HV_(0.5)121).The presence of nitride ceramics results in a higher micro *** cladded surface is free from cra.k. and *** average clad thickness is found to be around 0.6 mm.

关键词： laser cladding Taguchi orthogonal array artificial neural network microhardness microstructure