Computational analysis of radiative heat transfer due to rotating tube in parabolic trough solar collectors with Darcy Forchheimer porous medium

This attempt numerically investigates the heat transfer in parabolic trough solar collectors due to the rotating tube for the hybrid nanofluid flow over the Riga surface with Darcy Forchheimer’s porous medium under the effect of solar radiation. The influences of viscous dissipation and Joule heating are also considered. Equations governing the fluid flow are non-dimensionalized by implementing appropriate similarity variables. The resulting non-dimensionalized ordinary differential equations are solved using the shooting technique with Adam Bashforth and Adam Moulten’s fourth-order numerical approach. The numerical outcomes for various influential physical parameters regarding the fluid velocity, temperature, Nusselt number, and entropy generation are presented in graphical form. It is observed that the thermal profile escalates with the higher values of Reynold’s number, modified magnetic field parameter, and Prandtl number. Also, the Nusselt number diminishes with augmenting values of the Eckert number, modified magnetic field parameter, Forchheimer number, and Darcy number. The optimization of heat transfer in parabolic trough collectors is essential to improve the performance of solar collectors. The concentrated solar power technology is adequate for storing radiation energy in higher amounts.Author U.F.-G. appreciates the support of the Government of the Basque Country, Grant N. ELKARTEK 22/85 and ELKARTEK 21/10. The research is supported by Researchers Supporting Project number (RSP2023R158), King Saud University, Riyadh, Saudi Arabia

Growth and Characterization of Single Crystals ofl-Histidine Hydrochloride Monohydrate for Nonlinear Optical Applications

In the present study, we have focused on the growth of semi-organic single crystals, as they play a vital role in the generation of a terahertz pulse and its potential applications. The single crystals ofl-histidine hydrochloride monohydrate (LMHCL) were grown by slow evaporation solution growth by using deionized water as a solvent in a controlled atmosphere. Good quality crystals of the required size were obtained within 2 weeks. To estimate the lattice dimensions and get the structural information, powder x-ray diffraction (PXRD) study was performed in which we have found that the crystal belongs to the orthorhombic crystal system with space groupP2(1)2(1)2(1). The functional groups and the corresponding vibrational mode were confirmed using Fourier transform infrared (FTIR) and Raman spectroscopy, respectively. To study the optical properties UV-Vis transmission spectrum and photoluminescence (PL) were recorded. It was observed that the single crystal has a high value of transmission over a long range of wavelength which signifies that the crystal is a good candidate for nonlinear optical (NLO) applications. The UV cut-off wavelength is found to be 236 nm. The grown single crystals were studied by time-domain terahertz spectroscopy (THz-TDS) for photonic applications and the refractive indices were calculated and it is found that the refractive index is nearly equal to 3.4

Dopunska prehrana ribljim uljem poboljšala je funkciju jajnika, koncepciju i određene reprodukcijske pokazatelje kod kobila pasmine marvari

We investigated the effect of dietary fish oil supplementation on the development of the ovarian follicles, corpus luteum (CL), conceptus and certain reproductive events in Marwari mares, since it is reported to improve reproduction in cows. Accordingly, non-lactating mares (n = 20) were randomly assigned into two groups (10 per group) and fed either the control diet (CTR) or a diet enriched with fish oil (FOS) to supplement n-3 polyunsaturated fatty acids (PUFA) at the rate of 64 mg/kg body weight/day for 70 days or until 45 days post-ovulation in the mares that became pregnant. Estrus was detected using a teaser and insemination was performed using frozen thawed semen in the experimental mares. Development of the ovarian follicle, CL and conceptus were recorded using trans-rectal ultrasonography. Plasma concentrations of progesterone and estradiol were estimated by radioimmunoassay. In the FOS group, the diameter of the largest follicle from day 4 of estrus until ovulation, and the diameter of the CL on day 7 post-ovulation (D7PO) were greater (P<0.05). However, on day 15 post-ovulation (D15PO), the CL diameter increased significantly in the pregnant mares. Dietary fish oil significantly improved the development of the embryo as evidenced by an increase in the diameter of the embryonic vesicle on day 15 post-ovulation (D15PO), and the embryo proper on day 28 post ovulation (D28PO). Further, the mean plasma estradiol concentration was higher on the day of estrus onset (P<0.05) and day 4 of estrus (P<0.01) in the FOS group. Similarly, dietary fish oil significantly increased the plasma progesterone on D15PO in the pregnant mares (P<0.01). Although the duration of estrus was shorter by 19 hours (P<0.05), the length of the estrous cycle did not vary in the FOS group. A non-significant increase in the pregnancy rate was observed in the mares that received fish oil. It was concluded that dietary fish oil supplementation improved ovarian function and embryonic development in the Marwari mares.Na temelju prethodnih izvješća o poboljšanju reprodukcije krava, kod kobila pasmine marvari istražili smo učinak ribljeg ulja kao prehrambenog dodatka na razvoj folikula jajnika, žutog tijela, koncepcije i određenih reprodukcijskih pokazatelja. U skladu s ciljem, 20 kobila koje nisu bile u laktaciji je metodom slučajnog izbora podijeljeno u dvije skupine s po 10 kobila. Za razliku od kontrolne skupine, kobile u eksperimentalnoj skupini hranjene su obrokom obogaćenim ribljim uljem u obliku dodatka koji je sadržavao n-3 polinezasićene masne kiseline (PUFA), u dnevnoj količini od 64 mg na jedan kg tjelesne mase. Eksperiment je trajao 70 dana, odnosno za kobile koje su ostale gravidne do 45 dana nakon ovulacije. Estrus je praćen teaserom, a osjemenjivanje je provedeno zamrznutim sjemenom. Razvoj folikula jajnika i žutih tijela te gravidnosti praćeni su transrektalnim ultrazvukom. Koncentracija progesterona i estradiola u plazmi procijenjena je radioimunološkom metodom. U eksperimentalnoj skupini utvrđen je veći (P<0,05) promjer najvećeg folikula od 4. dana estrusa do ovulacije i veći promjer žutog tijela 7. dan nakon ovulacije. No, 15. dan nakon ovulacije promjer žutih tijela bio je signifikantno povećan kod gravidnih kobila. Obrok obogaćen ribljim uljem signifikantno je poboljšao razvoj embrija, što se očitovalo povećanjem promjera embrionalne vezikule 15. dan nakon ovulacije i povećanjem embrija 28. dan nakon ovulacije. Nadalje, u eksperimentalnoj skupini kobila srednja koncentracija estradiola u plazmi bila je veća na dan početka estrusa (P<0,05) i 4. dan estrusa (P<0,01). Slično tome, obrok obogaćen ribljim uljem kod gravidnih je kobila signifikantno (P<0,01) povećao progesteron u plazmi 15. dan nakon ovulacije. U kobila eksperimentalne skupine je, uz varijacije estrusnog ciklusa, utvrđeno i za 19 sati kraće trajanje estrusa (P<0,05). Povećana stopa gravidnosti kod kobila dohranjivanih ribljim uljem nije bila signifikantna. Zaključeno je da je hranidba s dodatkom ribljeg ulja kod kobila pasmine marvari poboljšala funkciju jajnika i razvoj embrija

Effect of MHD on unsteady oscillatory Couette flow through porous media

This paper describes the effects of a magnetic field on unsteady free convection oscillatory systems. When temperature and species concentration fluctuate with time around a non-zero constant, "Couette flow" across a porous medium occurs. The system of non-linear ODEs that governs the flow is solved analytically using the perturbation approach because the amplitude of fluctuations is very tiny. Mean flow and transient velocity, transient concentration, transient temperature, heat transfer, mean skin friction and phase and amplitude of skin friction. All have approximate solutions. The influence of different parameters on flow characteristics has been specified and discussed

Darcy-Forchheimer hybrid nanofluid flow over the rotating Riga disk in the presence of chemical reaction: Artificial neural network approach

The aim of present study is to examine the augmentation of thermal energy transfer in hybrid nanofluid flow caused by a rotating Riga disk in the presence of thermal radiation and chemical reaction. The silver and aluminium oxide nanoparticles are used to examine the thermal effect of water base fluid. The Darcy-Forchheimer model is considered to endorse the inertial and porous media effects and makes the model more realistic from the physical scenario. Levenberg-Marquardt backpropagation algorithm is considered to analyze the hybrid nanofluid’s properties. Using scaling group transformations, the governing partial differential equations are transformed into a system of ordinary differential equations. Resulting ordinary differential equations are solved numerically by applying a suitable shooting technique by MATLAB. The results obtained for the governing differential equations have been incorporated into a dataset on which the neural network has been trained. The effects of physical parameters have been analyzed for velocity, temperature, and concentration profiles. The determination, designing, convergence, verification, and stability of the Levenberg-Marquardt backpropagation neural network algorithm are validated on the assessment of achieved accuracy through performance, fit, regression, and error histogram plots for the discussed hybrid nanofluid. It is observed that fluid velocity reduces for enhanced Darcy-Forchheimer number, magnetic parameters and boosted for enhanced modified Hartmann number. Temperature profile increases by increasing the Brownian motion and thermophoresis parameters

Stress Dependent Band Gap Shift and Valence Band Studies in ZnO Nanorods

ZnO nanorods are grown on seedless and ZnO seeded glass substrates using chemical solution method and their structural, morphological, optical and valence band studies have been carried out. On seedless substrate horizontal nanorods are observed whereas for the seeded substrates vertically aligned hollow and solid nanorods grows. X-ray diffraction analysis revealed the presence of tensile stress in the vertical nanorods. Blue shift has been observed in the band gap of the vertical nanorods as compared to the horizontal nanorods which is attributed to the presence of tensile stress in the vertically aligned nanorods. Photoluminescence spectra revealed the dominance of Zinc vacancies (VZn) related defects in the nanorods and oxygen defects are found to be higher in the vertically aligned nanorods as compared to the horizontal nanorods. The difference between the Fermi level and valence band maxima for horizontal, hollow vertical and solid vertical nanorods are found to be ∼0.56 eV, ∼0.70 eV and ∼0.92 eV respectively indicating the possibility of p-type of conduction in the nanorods which has been attributed to presence of VZn defects in the ZnO nanorods

Instability in an amorphous In-Ga-Zn-O field effect transistor upon water exposure

The instability of an amorphous indium-gallium-zinc oxide (IGZO) field effect transistor is investigated upon water treatment. Electrical characteristics are measured before, immediately after and a few days after water treatment in ambient as well as in vacuum conditions. It is observed that after a few days of water exposure an IGZO field effect transistor (FET) shows relatively more stable behaviour as compared to before exposure. Transfer characteristics are found to shift negatively after immediate water exposure and in vacuum. More interestingly, after water exposure the off current is found to decrease by 1-2 orders of magnitude and remains stable even after 15 d of water exposure in ambient as well as in vacuum, whereas the on current more or less remains the same. An x-ray photoelectron spectroscopic study is carried out to investigate the qualitative and quantitative analysis of IGZO upon water exposure. The changes in the FET parameters are evaluated and attributed to the formation of excess oxygen vacancies and changes in the electronic structure of the IGZO bulk channel and at the IGZO/SiO2 interface, which can further lead to the formation of subgap states. An attempt is made to distinguish which parameters of the FET are affected by the changes in the electronic structure of the IGZO bulk channel and at the IGZO/SiO2 interface separately

A ZnO/PEDOT:PSS based inorganic/organic hetrojunction

An inorganic/organic hetrojunction has been fabricated by spin coating the p-type polymer poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on an n-type zinc oxide (ZnO) film. The ZnO film was deposited by the ultrasonically assisted chemical vapor deposition method on a patterned indium tin oxide (ITO) coated glass substrate. Gold was deposited on top of the PEDOT:PSS film by thermal evaporation. The current–voltage (I–V) characteristic of ZnO/PEDOT:PSS shows diode-like behavior. The I–V characteristic was examined in the framework of the thermionic emission model. The ideality factor and barrier height were obtained as 3.8 and 0.63 eV respectively