This communication presents the experimental study and performance analysis of a solar air heater with and without phase change
material (PCM) viz. paraffin wax and hytherm oil. There are three different arrangements viz. without PCM, with PCM and with
hytherm oil to study the comparative performance of this experimental system. Inlet, outlet temperatures and radiation with
respect to time have been recorded and found that the output temperature in case with thermal energy storage (TES) is higher
than that of without TES, besides, the outlet temperature with paraffin wax is slightly greater than that of with hytherm
oil. Also there is no energy gain in the evening in case of without TES but in case of with TES there is a heat gain for around
4 h in the evening which gives the backup for hot air for around four more hours which is the main advantage of this systems
with TES. Based on the data, the efficiency of the system has been calculated and it is noted that the efficiency in the case
of heat storage is higher than that of without TES, besides the efficiency in the case of the paraffin wax is slightly higher
than that of the hytherm oil case. 相似文献
A model for the quasistatic evolution of martensitic phase boundaries is presented. The model is essentially the gradient
flow of an energy that can contain elastic energy due to the underlying change in crystal structure in the course of the phase
transformation and surface energy penalizing the area of the phase boundary. This leads to a free boundary problem with a
nonlocal velocity that arises from a coupling to the elasticity equation. We show existence of solutions under a technical
convergence condition using an implicit time-discretization. 相似文献
Shape-memory alloys undergo a solid-to-solid phase transformation involving a change of crystal structure. We examine model
problems in the scalar setting motivated by the situation when this transformation is induced by the application of stress
in a polycrystalline material made of numerous grains of the same crystalline solid with varying orientations. We show that
the onset of transformation in a granular polycrystal with homogeneous elasticity is in fact predicted accurately by the so-called
Sachs bound based on the ansatz of uniform stress. We also present a simple example where the onset of phase transformation
is given by the Sachs bound, and the extent of phase transformation is given by the constant strain Taylor bound. Finally
we discuss the stress–strain relations of the general problem using Milton–Serkov bounds. 相似文献
Summary: We report a new method for the preparation of polyaniline nanoballs by using HAuCl4 as an oxidizing agent. During the reaction, aniline is oxidized and forms polyaniline whilst the hydrogen tetrachloroaurate is reduced and forms gold nanoparticles. These gold nanoparticles are found to decorate the nanoballs.
The resultant precipitate and corresponding TEM image of the gold‐nanoparticle covered polyaniline nanoball. 相似文献
Multimodal approaches combined with various nanomaterials and advanced techniques have been developed for synergistic cancer treatment. Among various therapies, conventional chemotherapy (CHT) is a direct cancer treatment that can produce unintended side effects due to nonspecific action on both the tumor and normal cells; patient-friendly photothermal therapy (PTT) may be able to treat embedded tumors in vital regions with minimal invasion but does not guarantee complete removal of cancers. However, the combination of CHT-PTT may provide a promising tool for direct cancer treatment with minimal side effects. In this regard, nanostructured materials, such as gold nanorods with tuned size and surface characteristics, are key components designed to enhance the heating capacity and active or passive delivery of drugs to the tumor site. In this review, the pioneering work synergizing CHT and PTT is summarized, and the current state-of-the-art in the development of inorganic and organic nanocomposites for combinational therapy is described. 相似文献
A series of (C9H7)2Zr(OAr)Cl and (C9H7)2Zr(OAr)2 complexes, where Ar = C6H5, p-ClC6H4, α-C10H7, or β-C10H7, have been synthesised by the reaction of bis(indenyl)zirconium(IV)-dichloride with an appropriate phenol in a 1:1 and 1:2 molar ratio in refluxing benzene in the presence of triethylamine. These complexes have been characterised by elemental analyses, conductance measurements and spectral (IR, 1H NMR and electronic) studies. 相似文献
Benzyltriethylammonium tetracosathioheptamolybdate [(C6H5CH2N(Et)3)6Mo7S24] has been found to be a superior sulfur transfer reagent for the conversion of alkyl halides to the corresponding disulfides in excellent yields under very mild reaction conditions. 相似文献
We propose a variant of the time-dependent multi-configuration Hartree method within the framework of Fourier grid Hamiltonian
method. The workability of the method proposed is demonstrated with a well-known coupled two-mode problem. 相似文献
The kinetics of isothermal decomposition of solid K2Zr2(O2)2F6·2H2O have been studied in the temperature range 100–226° under vacuum. The fractional decomposition has been determined by measuring the pressure of evolved oxygen during pyrolysis with the help of a McLeod gauge. The values ranged from 0.05 to 0.62. The vs. t data showed that the kinetics are deceleratory throughout the course of the reaction. The initial part of the decomposition reaction could be best described by a unimolecular decay law, while the later stages obey contracting volume kinetics. The activation energies have been determined and the respective values for the above stages are 13.6 and 6.9 kcal·mole–1.
Zusammenfassung Die Kinetik der isothermen Zersetzung von festen K2Zr2(O2)2F6·2H2O wurde im Temperaturbereich von 100–226° im Vakuum untersucht. Die fraktionierte Zersetzung wurde durch Messung des Druckes des während der Pyrolyse entwickelten Sauerstoffs mit einem McLeod-Manometer bestimmt. Die -Werte variierten von 0.05 bis 0.62. Die -t Daten zeigen, daß die Kinetik im Verlauf der Reaktion herabgesetzt wird. Der erste Teil der Zersetzungsreaktion konnte am besten durch ein unimolekulares Zerfallgesetzt beschrieben werden, während die späteren Phasen der Kinetik der Volumenkontraktion gehorchten. Die Aktivierungsenergien wurden berechnet und die entsprechenden Werte für obige Reaktionen ergaben sich 13.6 bzw. 6.9 Kcal mol–1.