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211.
This paper presents an exact solution for steady-state conduction heat transfer in cylindrical composite laminates. This laminate
is cylindrical shape and in each lamina, fibers have been wound around the cylinder. In this article heat transfer in composite
laminates is being investigated, by using separation of variables method and an analytical relation for temperature distribution
in these laminates has been obtained under specific boundary conditions. Also Fourier coefficients in each layer obtain by
solving set of equations that related to thermal boundary layer conditions at inside and outside of the cylinder also thermal
continuity and heat flux continuity between each layer is considered. In this research LU factorization method has been used to solve the set of equations. 相似文献
212.
In the current research paper, a conservative system comprising of a mass grounded by linear and nonlinear springs in series connection is studied. The equation of motion for the aforementioned system has been derived as a nonlinear ordinary differential equation with inertia and static–type cubic nonlinearities. The global residue harmonic balance method is applied to obtain an approximate analytical frequency and periodic solution of the problem. Using the obtained analytical expressions, the influences of the hardening and softening nonlinear spring on the non–dimensional frequency are investigated. The results show that developing the system nonlinearity leads the displacement of the mass and the deflection of linear spring to approach each other. Moreover, comparison of the results obtained using the proposed procedure with those achieved by other methods such as numerical method, variational iteration method and harmonic balance approach demonstrates the accuracy and advantages of the current approach. 相似文献
213.
Amir Alaei Morteza Hasanzadeh Kafshgari Shahab Kashani Rahimi 《Heat and Mass Transfer》2013,49(2):285-290
New experimental results present the effects of low-frequency vibrations in a vertical heat pipe. The thermal resistance was investigated under different heat transfer rates, filling ratios and frequencies, increase of which improved the thermal performance. The vibrations were effective 33.83 % on the performance, and the best performance was estimated using the L16 array of Taguchi method, and it was achieved with the thermal resistance 0.064 K/W in the frequency 30 Hz. 相似文献
214.
Y. A. Shahab 《Magnetic resonance in chemistry : MRC》1977,9(10):580-583
Correction of measured chemical shifts by subtracting the diamagnetic contributions caused by certain substituents on various carbons of a molecule leads to data that allow a reasonable interpretation of substituent effects on chemical shifts in 13C n.m.r. spectroscopy. It is shown that both paramagnetic and diamagnetic terms increase on all carbons of a molecule when the atomic number of a substituent increases down the same group of the periodic table. An explanation of α-, β-, and γ- effects for methyl substitution using the same procedure is attempted. 相似文献
215.
Leila?FarzinEmail author Mojtaba?Shamsipur Leila?Samandari Shahab?Sheibani 《Mikrochimica acta》2018,185(5):276
This review (with 340 refs) focuses on methods for specific and sensitive detection of metabolites for diagnostic purposes, with particular emphasis on electrochemical nanomaterial-based sensors. It also covers novel candidate metabolites as potential biomarkers for diseases such as neurodegenerative diseases, autism spectrum disorder and hepatitis. Following an introduction into the field of metabolic biomarkers, a first major section classifies electrochemical biosensors according to the bioreceptor type (enzymatic, immuno, apta and peptide based sensors). A next section covers applications of nanomaterials in electrochemical biosensing (with subsections on the classification of nanomaterials, electrochemical approaches for signal generation and amplification using nanomaterials, and on nanomaterials as tags). A next large sections treats candidate metabolic biomarkers for diagnosis of diseases (in the context with metabolomics), with subsections on biomarkers for neurodegenerative diseases, autism spectrum disorder and hepatitis. The Conclusion addresses current challenges and future perspectives. 相似文献
216.
Seyyedeh Masoumeh Mousavifar Hassan Kefayati Shahab Shariati 《Journal of heterocyclic chemistry》2020,57(1):157-162
A simple, economical, three-component, and one-pot synthesis of novels spiro[indoline-3,5′-pyrido[2,3-d]pyrimidine] derivatives by condensation of dimethyl acetylene dicarboxylate, isatin derivatives, and 6-amino-1,3-dimethyluracil in presence of Fe3O4@Propylsilane@Histidine[HSO4−] as an impressive catalyst via reflux and ultrasound procedure is described. The results show that ultrasound method has several advantages such as milder condition, shorter reaction time, and higher reaction yield. 相似文献
217.
In the present work we report, for the first time, the successful on-line coupling of chiral MEKC (CMEKC) to atmospheric pressure photoionization MS (APPI-MS). Four structurally similar neutral test solutes (e.g. benzoin (BNZ) derivatives) were successfully ionized by APPI-MS. The mass spectra in the positive ion mode showed that the protonated molecular ions of BNZs are not the most abundant fragment ions. Simultaneous enantioseparation by CMEKC and on-line APPI-MS detection of four photoinitiators, hydrobenzoin, BNZ, benzoin methyl ether, benzoin ethyl ether, were achieved using an optimized molar ratio of mixed molecular micelle of two polymeric chiral surfactants (polysodium N-undecenoxy carbonyl-L-leucinate and polysodium N-undecenoyl-L,L-leucylvalinate). The CMEKC conditions, such as voltage, chiral polymeric surfactant concentration, buffer pH, and BGE concentration, were optimized using a multivariate central composite design (CCD). The sheath liquid composition (involving %v/v methanol, dopant concentration, electrolyte additive concentration, and flow rate) and spray chamber parameters (drying gas flow rate, drying gas temperature, and vaporizer temperature) were also optimized with CCD. Models built based on the CCD results and response surface method were used to analyze the interactions between factors and their effects on the responses. The final overall optimum conditions for CMEKC-APPI-MS were also predicted and found in agreement with the experimentally optimized parameters. 相似文献
218.
Khansa Jamil Sahir Hameed Khattak Anum Farrukh Sania Begum Muhammad Naeem Riaz Aish Muhammad Tahira Kamal Touqeer Taj Imran Khan Sundus Riaz Huma Batool Kaleemullah Mandokhail Sabahat Majeed Sajid Ali Khan Bangash Alia Mushtaq Shahab Bashir Imdad Kaleem Fahed Pervaiz Aamir Rasool Muhammad Ammar Amanat Ghulam Muhammad Ali 《Molecules (Basel, Switzerland)》2022,27(19)
Background: Type 2 diabetes mellitus (DM2) is a chronic and sometimes fatal condition which affects people all over the world. Nanotherapeutics have shown tremendous potential to combat chronic diseases—including DM2—as they enhance the overall impact of drugs on biological systems. Greenly synthesized silver nanoparticles (AgNPs) from Catharanthus roseus methanolic extract (C. AgNPs) were examined primarily for their cytotoxic and antidiabetic effects. Methods: Characterization of C. AgNPs was performed by UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and atomic force microscopy (AFM). The C. AgNPs were trialed on Vero cell line and afterwards on an animal model (rats). Results: The C. AgNPs showed standard structural and functional characterization as revealed by FTIR and XRD analyses. The zetapotential analysis indicated stability while EDX analysis confirmed the formation of composite capping with Ag metal. The cytotoxic effect (IC50) of C. AgNPs on Vero cell lines was found to be 568 g/mL. The animal model analyses further revealed a significant difference in water intake, food intake, body weight, urine volume, and urine sugar of tested rats after treatment with aqueous extract of C. AgNPs. Moreover, five groups of rats including control and diabetic groups (NC1, PC2, DG1, DG2, and DG3) were investigated for their blood glucose and glycemic control analysis. Conclusions: The C. AgNPs exhibited positive potential on the Vero cell line as well as on experimental rats. The lipid profile in all the diabetic groups (DG1-3) were significantly increased compared with both of the control groups (p < 0.05). The present study revealed the significance of C. AgNPs in nanotherapeutics. 相似文献
219.
Khan Shahab Ullah 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2023,77(8):1-18
The European Physical Journal D - The spectrum of quadruply ionized bismuth (Bi V) has been investigated in the vacuum ultraviolet region 190–1900 Å. Several bismuth... 相似文献