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1.
In the present work, the use of cylindrical turbulators in a double pipe heat exchanger has been investigated. Cylindrical fin type of turbulators has been placed circumferentially separated by 90° on the outer side of an inner pipe at a regular pitch. Experimental studies were undertaken for different air flow rates in a turbulent regime whose Reynolds number range between 2500 and 10000. Heat transfer characteristics like Nu and friction factor have been experimentally determined. Parametric studies were conducted by changing the pitch and also the orientation of the turbulators. Nu and friction factor were found to increase as the pitch is reduced. A model with alternatively changed orientation outperformed others by exhibiting highest Nu and reduced friction factor. 相似文献
2.
Jhansi Rani Sunkara Sathish Mohan Botsa 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2020,94(2):392-400
Russian Journal of Physical Chemistry A - Recently the researchers have shown great interest on photocatalysis, especially in dyes degradation by nanocomposites under visible light. In this work,... 相似文献
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Christopher J. Otolski A. Mohan Raj Vaidhyanathan Ramamurthy Christopher G. Elles 《Chemical science》2020,11(35):9513
Ultrafast transient absorption spectroscopy reveals new excited-state dynamics following excitation of trans-azobenzene (t-Az) and several alkyl-substituted t-Az derivatives encapsulated in a water-soluble supramolecular host–guest complex. Encapsulation increases the excited-state lifetimes and alters the yields of the trans → cis photoisomerization reaction compared with solution. Kinetic modeling of the transient spectra for unsubstituted t-Az following nπ* and ππ* excitation reveals steric trapping of excited-state species, as well as an adiabatic excited-state trans → cis isomerization pathway for confined molecules that is not observed in solution. Analysis of the transient spectra following ππ* excitation for a series of 4-alkyl and 4,4′-dialkyl substituted t-Az molecules suggests that additional crowding due to lengthening of the alkyl tails results in deeper trapping of the excited-state species, including distorted trans and cis structures. The variation of the dynamics due to crowding in the confined environment provides new evidence to explain the violation of Kasha''s rule for nπ* and ππ* excitation of azobenzenes based on competition between in-plane inversion and out-of-plane rotation channels.Ultrafast transient absorption spectroscopy reveals new excited-state dynamics following excitation of trans-azobenzene (t-Az) and several alkyl-substituted t-Az derivatives encapsulated in a water-soluble supramolecular host–guest complex. 相似文献
5.
<正>Polyoxometalates (POMs), a class of discrete anionic metal oxides in groups Ⅴ and Ⅵ, are constructed via the condensation of metal oxide polyhedral (MO_x, M=W~(Ⅵ), Mo~(Ⅵ),V~Ⅴ, Nb, Ta, etc. and x=4–7) with each other in a corner-,edge-, or rarely in a face-sharing manner [1–3]. Up to now,the broadening family of POM derivatives ranges from small 相似文献
6.
天然气水合物作为一种储量大、无污染的清洁能源近些年受到了广泛关注. 近20年来,中国进行了较大范围的陆海域天然气水合物储层勘探与储量预测.2017年,中国地质调查局牵头对南海神狐海域的天然气水合物进行了基于降压渗流原理的试验性开采.国内外已进行的水合物试采工程面临着气体产量低、出砂较多等问题,其最主要的原因之一是开发过程中沉积物内复杂多相渗流机理尚不明晰.本文综述了平行毛细管模型、Kozeny模型等广泛应用于天然气水合物开发渗流分析的理论模型,对比分析了水合物开发多尺度渗流过程模拟方法,简述了国内外含水合物沉积物渗透率测试、渗流过程中沉积物物性演变以及水合物开采室内模拟等方面的渗流实验进展,总结了矿场尺度的天然气水合物储层开采过程中产气数值模拟手段,展望了多相渗流模型、储层原位含水合物样品室内测试及结构与物性演化、矿场尺度数值模拟与水平井压裂技术等应用研究的未来方向与挑战. 相似文献
7.
C.E. Satheesh Pushpanathan N. Sathish Kumar P. Raghavendra Kumara Ramasamy Karvembu Amar Hosamani M. Nethaji 《应用有机金属化学》2019,33(10)
Two new half‐sandwich Ru (II)(p‐cymene) complexes ( 1 and 2 ) containing dopamine‐based (N, O) Schiff base ligands ( L 1 H and L 2 H ) were synthesized and characterized by FT‐IR, UV–Visible and 1H & 13C NMR spectral techniques, and elemental analyses. The spectroscopic and analytical data revealed monobasic bidentate coordination of the ligands with Ru ion. The molecular structures of L 1 H , L 2 H and 2 were further confirmed by single crystal X‐ray diffraction study. Complexes 1 and 2 have been employed as catalysts in the transfer hydrogenation of ketones using 2‐propanol as a hydrogen source at 85 °C under base‐free condition. Good to the excellent yield of secondary alcohols, gram scale synthesis, and high TON and TOF made this catalytic system interesting. 相似文献
8.
Jilloju Parameshwara Chary Persoons Leentje Kurapati Sathish Kumar Schols Dominique De Jonghe Steven Daelemans Dirk Vedula Rajeswar Rao 《Molecular diversity》2022,26(3):1357-1371
A new series of (?±)-(3-(3,5-dimethyl-1H-pyrazol-1-yl)-6-phenyl-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-7-yl)(phenyl)methanones were efficiently synthesized starting from 4-amino-5-hydrazinyl-4H-1,2,4-triazole-3-thiol 1, acetyl acetone 2, various aromatic and heterocyclic aldehydes 3 and phenacyl bromides 4. All the newly synthesized compounds were tested for their antiviral and antitumoral activity. It was shown that subtle structural variations on the phenyl moiety allowed to tune biological properties toward antiviral or antitumoral activity. Mode-of-action studies revealed that the antitumoral activity was due to inhibition of tubulin polymerization.
Graphic abstract 相似文献9.
Journal of Solid State Electrochemistry - Development of high-performance energy storage devices is a vital research area to meet the present-day energy demand. In the work carried toward the... 相似文献
10.
Chinmoy Biswas Prof. Venugopal Rao Soma Dr. Prabhakar Chetti Dr. Sai Santosh Kumar Raavi 《Chemphyschem》2021,22(24):2562-2572
An all-inclusive investigation of the ultrafast excited state relaxation dynamics of a triphenylmethane derivative molecule, New Fuchsine (NF), using a combined approach of density functional theory (DFT), femtosecond transient absorption spectroscopy (fs-TAS), and photoluminescence spectroscopy is presented in this work. The DFT calculations confirmed the formation of twisted molecular structure in the excited state of NF in ethanol solution with bond rotation of ≈86°. TAS measurements of NF solution exhibited ultrafast ground state-recovery pathway via a conical intersection confirming an ultrafast structural reorientation. On the contrary, TAS measurements of NF thin-film exhibited a longer excited-state lifetime suggesting a hindered molecular twisted state formed as an intermediate step. Photophysical kinetic models are proposed to globally fit the fs-TAS data establishing the twisted intramolecular charge transfer (TICT) state mediated ground state recovery for NF in solution and thin film, respectively. Temperature-dependent photoluminescence study of NF film provided a clear insight into the effect of rotational motion of phenyl rings in NF molecules over the TICT mediated emission. 相似文献