Thermal Character Research Articles

Experimental Investigation on Thermal Characteristics of Hollow Ball Screw in Different Working Conditions

The text takes Z-Axis of precision machine tool as study object, and proceed the thermal character's experiment of Z-Axis feed system in different working condition (different Cooling strategy, different Feeding speed, load or not). The data of experiment shows the higher of the feed speed, the more heat is generated. Position accuracy can be increase by apply the right load and load is nearly none business with temperature rise. Cooling strategy is nearly none business with temperature rise and may cause the discretization of position accuracy.

Analysis on Thermal Character of Interface Between Rail and Armature for Electromagnetic Railgun

The thermal character of the interface between rail and armature significantly affects the launch performance of electromagnetic railguns. In this paper, the friction coefficient μ between brass and aluminum is discussed; it is found that, under hypervelocity and electrical contact conditions, μ maintains an order of magnitude of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> or less, which is smaller than that under normal conditions. A 2-D simulation model is developed to analyze the temperature character of armature contact surface caused by friction, and the simulated results concretely demonstrate the order of magnitude of μ when armature is launching in bore. Another 3-D simulation model is also developed to obtain the temperature distribution on the armature contact surface under high current. According to simulation results of interface temperature distribution, the thermal effect on armature wear and contact performance is analyzed. For an electromagnetic railgun with hypervelocity and high current, it is concluded that the heat generated by friction and high current can cause armature surface film to melt and cause armature edges of ends to be damaged. The aluminum film is helpful to improve the contact performance.

Charged Particles’ Hawking Radiation via Tunneling of Both Horizons from Reissner-Nordström-Taub-NUT Black Holes

In some recent derivations thermal characters of the inner horizon have been employed; however, the understanding of possible role that may play the inner horizons of black holes in black hole thermodynamics is still somewhat incomplete. Motivated by this problem we investigate Hawking radiation of the Reissner-Nordstrom-Taub-NUT (RNTN) black hole by considering thermal characters of both the outer and inner horizons. We apply Damour-Ruffini method and the thin film brick wall model to calculate the temperature and the entropy of the inner horizon of the RNTN black hole. The inner horizon admits thermal character with positive temperature and entropy proportional to its area, and it thus may contribute to the total entropy of the black hole in the context of Nernst theorem. Considering conservations of energy and charge and the back-reaction of emitting particles to the spacetime, the emission spectra are obtained for both the inner and outer horizons. The total emission rate is the product of the emission rates of the inner and outer horizons, and it deviates from the purely thermal spectrum and can bring some information out. Thus, the result can be treated as an explanation to the information loss paradox.

Research on Thermal Character of Inorganic High Temperature Phase Change Materials

Recently advances in testing methods and study of the inorganic salt establish the high temperature phase change energy storage materials as a promising candidate for solar thermal power generation, industrial process heat use and waste heat recovery. In this paper, a phase change model related to the warming-cooling method was established to test the phase change temperature and the heat of LiCl-NaCl(1.08-1) and Ca(NO3)2-NaNO3(4-7). The result tested by the warming-cooling method is mainly in line with the one tested by other method. The data allows a promising development of the energy storage.

Emission State Hierarchy Governed Coherence and Intensity Noise Properties of Quantum Dot Superluminescent Diodes

There is an inherent link between the coherence properties in the first and second order, depending on the quantum optical characteristics of the light emitting source. Whereas the coherence in the first order reflects the spectral distribution of radiation, the coherence in the second order describes the intensity fluctuations of photonic beams quantified by the relative intensity noise. In this paper, we demonstrate how the particularly interesting and highly complex spectral emission state hierarchy of a quasi-zero-dimensional inhomogeneously broadened quantum dot superluminescent diode governs both the coherence and intensity noise properties. We confirm that indeed a generalized Hodara formula reflecting the pure thermal emission character of the investigated quantum dot superluminescent diode quantitatively explains the experimentally observed complex intensity noise behavior just by the observed complex spectral behavior.

EFFECTIVE TEMPERATURE, HAWKING RADIATION AND QUASINORMAL MODES

Parikh and Wilczek have shown that Hawking radiation's spectrum cannot be strictly thermal. Such a nonstrictly thermal character implies that the spectrum is also not strictly continuous and thus generates a natural correspondence between Hawking radiation and black hole's quasinormal modes. This issue endorses the idea that, in an underlying unitary quantum gravity theory, black holes result in highly excited states. We use this key point to re-analyze the spectrum of black hole's quasinormal modes by introducing a black hole's effective temperature. Our analysis changes the physical understanding of such a spectrum and enables a re-examination of various results in the literature which realizes important modifications on quantum physics of black holes. In particular, the formula of the horizon's area quantization and the number of quanta of area are modified into functions of the quantum "overtone" number n. Consequently, Bekenstein–Hawking entropy, its sub-leading corrections and the number of microstates, i.e. quantities which are fundamental to realize unitary quantum gravity theory, are also modified. They become functions of the quantum overtone number too. Previous results in the literature are re-obtained in the very large n limit.

Temperature Enhancement of Zinc and Iron Separation from Chromium(III) Passivation Baths by Emulsion Pertraction Technology

This work reports the influence of the temperature on the selective removal of zinc and iron from a chromium(III) passivation bath by emulsion pertraction technology using Cyanex 272 as extractant and hollow fiber membrane contactors. The results indicate that the kinetics of the separation was largely influenced by the temperature in the range 10–40 °C. The viscosity of the organic liquid phase was measured at different temperatures and extractant concentrations, and the results were fitted to the Riedel and Grunberg and Nissan correlations. The improvement observed from 20 to 40 °C was explained by the increase in the diffusion coefficient of the zinc and iron organometallic complexes through the liquid membrane. However, the remarkably slower zinc and iron separation rates observed at 10 °C in comparison with those at 20–40 °C were attributed to a shift in the driving force due to an endothermic change of the interfacial extraction reaction. The equilibrium parameters at 10 and 20–40 °C were estimated by fitting the experimental kinetic results to the proposed mathematical model. Thus, this work addresses the thermal character of equilibrium and its relevant influence on the separation kinetics of reactive membrane systems.

Derivation of third-order nonlinear susceptibility of thin metal films as a delayed optical response

Metals typically have very large nonlinear susceptibilities, whose origin is mainly of thermal character. We model the cubic nonlinearity of thin metal films by means of a delayed response derived \textit{ab initio} from an improved version of the classic two temperature model. We validate our model by comparison with ultrafast pump-probe experiments on gold films.

Holographic Pomeron and the Schwinger mechanism

We revisit the problem of dipole-dipole scattering via exchanges of soft Pomerons in the context of holographic QCD. We show that a single closed string exchange contribution to the eikonalized dipole-dipole scattering amplitude yields a Regge behavior of the elastic amplitude; the corresponding slope and intercept are different from previous results obtained by a variational analysis of semiclassical surfaces. We provide a physical interpretation of the semiclassical worldsheets driving the Regge behavior for $(\ensuremath{-}t)&gt;0$ in terms of worldsheet instantons. The latter describe the Schwinger mechanism for string pair creation by an electric field, where the longitudinal electric field ${E}_{L}={\ensuremath{\sigma}}_{T}\mathrm{tanh}(\ensuremath{\chi}/2)$ at the origin of this nonperturbative mechanism is induced by the relative rapidity $\ensuremath{\chi}$ of the scattering dipoles. Our analysis naturally explains the diffusion in the impact parameter space encoded in the Pomeron exchange; in our picture, it is due to the Unruh temperature of accelerated strings under the electric field. We also argue for the existence of a ``micro-fireball'' in the middle of the transverse space due to the soft Pomeron exchange, which may be at the origin of the thermal character of multiparticle production in ep/pp collisions. After summing over uncorrelated multi-Pomeron exchanges, we find that the total dipole-dipole cross section obeys the Froissart unitarity bound.

Electronic phase diagram of LixCoO2revisited with potentiostatically deintercalated single crystals

Electronic phase diagram of LixCoO2 has been re-examined using potentiostatically de-intercalated single crystal samples. Stable phases of x ~ 0.87, 0.72, 0.53, 0.50, 0.43, and 0.33 were found and isolated for physical property studies. A-type and chain-type antiferromagnetic orderings have been suggested from magnetic susceptibility measurement results in x ~ 0.87 and 0.50 below ~ 10 K and 200 K, respectively, similar to those found in NaxCoO2 system. There is no Li vacancy superlattice ordering observed at room temperature for the electronically stable phase Li0.72CoO2 as revealed by synchrotron X-ray Laue diffraction. The peculiar magnetic anomaly near ~ 175 K as often found in powder samples of x ~ 0.46-0.78 cannot be isolated through this single crystal potentiostatic method, which supports the previously proposed explanation to be surface stabilized phase of significant thermal hysteresis and aging character.

Prilezhaev Dihydroxylation of Olefins in a Continuous Flow Process

Epoxidation of both terminal and non-terminal olefins with peroxy acids is a well-established and powerful tool in a wide variety of chemical processes. In an additional step, the epoxide can be readily converted into the corresponding trans-diol. Batch-wise scale-up, however, is often troublesome because of the thermal instability and explosive character of the peroxy acids involved. This article describes the design and semi-automated optimization of a continuous flow process and subsequent scale-up to preparative production volumes in an intrinsically safe manner.

Novel Ferrocene-Based Organometallic Poly(ether sulfone amide imide)s: Preparation, Characterization, and Properties

A new ferrocene-based diamine (ESAFDA) with built-in ether, sulfone, and amide groups was prepared via reaction of two synthetic precursors. Firstly, 1,1′-ferrocenedicarbonyl chloride was prepared from 1,1′-ferrocenedicarboxylic acid using oxalyl chloride. In another reaction, nucleophilic substitution reaction of 3-aminophenol with bis(4-chlorophenyl sulfone) was used for synthesis of 3,3′-(4,4′-sulfonyl bis(1,4-phenylene) bis (oxy)) dianiline (SBOD). Finally, the diamine was prepared via nucleophilic reaction of SBOD with 1,1′-ferrocenedicarbonyl chloride. The precursors and the diamine were characterized by conventional methods and the diamine was used for preparation of different ferrocene-based poly(ether sulfone amide imide)s through polycondensation with three different dianhydrides. The polymers were characterized by elemental analysis, FTIR and 1H-NMR spectroscopy. Various properties of the polymers including inherent viscosity, molecular weight, solubility, thermal stability and behavior, flame-retardant nature, mechanical properties, and crystallinity were studied. Presence of ferrocene structure in companion to ether, sulfone, and amide units in the backbone of polyimides led to improved solubility of the polymers in polar aprotic solvents and enhanced thermal stability and flame-retardant character of polyimides.

Fabrication of Pressureless Sintered β-Sialon-ZrO&lt;sub&gt;2&lt;/sub&gt; Composites

β-sialon-ZrO2composites with Si5AlON7 or Si4Al2O2N6 bonding phase were prapared in N2 atmosphere at 1550°C with Si, Al2O3, AlN and ZrO2 (Ca) as raw materials by reaction in situ pressureless sintering. Effect of Z value and content of β-sialon batch on its sintering performance, phase composition, microstructure, and thermal expansion character were investigated. Results showed that the phase of Si5AlON7 was formed in samples with β-sialon designing Z=1, and phases of Si5AlON7 and Si4Al2O2N6 were formed in samples with β-sialon designed Z=2 and β-sialon designed Z=3, respectively and Bending strength of samples increase with content of β-sialon batch. When content of β-sialon batch equals 10wt%, 15wt% and 15% respectively, the samples with β-sialon designed Z=1, Z=2, and Z=3 have lower apparent porosity, microstructure of homogeneous and compact and lower thermal expansion coefficient, respectively.

Corrosion and degradation performance of novel absorbent for CO2 capture in pilot-scale

Abstract The corrosion and degradation behavior of new blended amine absorbent specified by Toshiba were studied in the pilot plant under the condition of long-term operation. Three test campaigns of the CO2 capture were completed. One campaign was the base experiment to evaluate the thermal and oxidative degradation and corrosion character of new absorbent. Other two campaigns were operated to evaluate the influence of SO2 on the corrosion and degradation behavior of new absorbent. The results show that the SO2 removal efficiency is almost 100%. After addition of SO2 to simulated flue gas, there will be more serious amine degradation and HSS formation. The greater the SO2 concentration is, the more amine degradation and HSS formation. The point C which is outlet of the heat exchanger (rich liquid side) presents the most serious corrosion. Addition of SO2 plays an important role to form the corrosion protect films. It was difficult to form protect film and easily be destroyed at the presence of SO2 for stainless steel compared with carbon steel.

Exciting field phase effect on the entanglement death and birth phenomena for nonlinear coupler system

We consider time-evolution of the disentanglement process of once generated entangled qubit pair as a result of the phase variation of the pumping field. As a source of maximally entangled states we use the nonlinear coupler (two oscillators with Kerr-like nonlinearities) with nonlinear internal interactions. The coupler prepared in a maximally entangled state interacts afterwards with external reservoir of thermal character and pumping field as well. We show that the fact of the coupling with additional state (which can create additional entanglement with one of the 2-qubit system's previously entangled states) is an origin of interesting entanglement decay behaviour. We can observe shortening of both: entanglement death-time and entanglement birth caused by changing the phase of an external driving field.

A 3D dynamic analysis of thermal behavior during single-pass multi-layer weld-based rapid prototyping

Weld-based rapid prototyping enables the capacity of forming 3D complex parts. In rapid prototyping there exists the particular thermal cycling, being repeatedly heated at the same place, which is the basic cause of complex thermal stress. In this paper experiments are carried out to investigate the thermal characters of single-pass ten-layer deposition. Meanwhile a 3D transient heat transfer numerical simulation with temperature-dependent material properties is conducted to investigate temperature field evolution, thermal cycling character, temperature gradient and the effects of depositing directions on the thermal process of single-pass ten-layer rapid prototyping. The calculated results match the experimental measurements well. The research results show that the heat diffusion condition of molten pool becomes worse as the depositing height increases. With other parameters being constant, the heat diffusion condition can be significantly improved by optimizing the depositing directions. The heat diffusion condition of component with the same depositing directions is better than reverse directions.

The thermal character of the underwater heat exhausting source

The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water. In this paper, the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment. The results show that the thermal floating distance is related with the sailing velocity of the underwater target. The higher the velocity is, the longer the hot wake is, and the broader the hot scope is. The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity. The experimental results are accordant with the numerical simulation, and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.

Genuine multipartite nonlocality of entangled thermal states

We assess quantum non-locality of multiparty entangled thermal states by studying, quantitatively, both tripartite and quadripartite states belonging to the Greenberger-Horne-Zeilinger (GHZ), W and linear cluster-state classes and showing violation of relevant Bell-like inequalities. We discuss the conditions for maximizing the degree of violation against the local thermal character of the states and the inefficiency of the detection apparatuses. We demonstrate that such classes of multipartite entangled states can be made to last quite significantly, notwithstanding adverse operating conditions. This opens up the possibility for coherent exploitation of multipartite quantum channels made out of entangled thermal states. Our study is accompanied by a detailed description of possible generation schemes for the states analyzed.

Synthesis, Crystal Structure and Thermal Decomposition Character of an Environmentally‐Friendly Energetic Coordination Compound of [Co(NH3)4(NO3)](NO3)·0.5H2O

AbstractA new coordination compound of [Co(NH3)4(NO3)]NO3·0.5H2O was synthesized by reacting Co(NO3)2 with NH3·H2O aqueous solution. It has been characterized by using elemental analysis, FT‐IR technology, and X‐ray single crystal diffraction analysis. It belongs to the monoclinic crystal system and P(2)/n space group with the unit cell: a=0.74618(1) nm, b=2.26114(4) nm, c=1.04282(2) nm, β=92.038(1) °. The central ion Co(II) displays a stable octahedral configuration, which was constructed with the central ion Co(II), four nitrogen atoms from NH3 molecules and two oxygen atoms from NO−3. The outer sphere was NO−3 and a common crystalline water molecule, which connected the inner sphere by electrostatic force and the intermolecular force. The intermolecular and intramolecular hydrogen bonds constructed a three‐dimensional network structure, which increased the stability of the whole crystal structure. In addition, thermal decomposition character of the title complex was investigated by using TG‐DTG, DSC and FT‐IR technologies. There are two endothermic peaks and one exothermic one in the process of thermal decomposition, and the decomposition residue at 300°C is the mixture of CoO and Co2O3.

Characterization of mimetic lipid mixtures of stratum corneum

Lipid mixtures consisting of ceramide III, palmitic acid, and cholesterol were prepared at different thermal and humidity conditions. The lipid mixture, treated at temperature higher than 100 °C, displayed the similar thermal character to native human Stratum Corneum (SC), although hydration changed structural characters of the lipid mixtures as well as human SC: Hydration gave rise to the variation of lamellar distances in lipid mixtures such as lengthening of vertical repeat distance and slight-shortening of the lateral repeat distance. It also generated the configurational transition of amide groups. Since these variations depending on the heating and hydrating processes do not occur on pristine lipids, it can be confirmed that the lipid mixture forms hybrid phases by the association between heterogeneous lipids.