KINETICS OF DEPOSITION OF METAL IONS TO ACTIVATED CARBON FIBERS (ACFs) WITH FLUIDIZATION

1. INTRODUCTION Study on the deposition of metal ions on ACFs indicated that such a process consists of several consecutive steps [1]: (1) transfer of the solvated ions (metal ions) from the bulk solution to the proximity of the ACFs surface; (2) absorpt…     

Investigation on spontaneous ignition of two kinds of organic material with water

A systematic investigation was performed to elucidate the cause of spontaneous ignition of Refuse Derived Fuel (RDF) and Meat Bone Meal (MBM). Heat generation in both RDF and MBM with addition of water liquid and vapor at room temperature was determined by isothermal calorimetry. Compared with water liquid, the heat of wetting by sorption of water vapor at 80% relative humidity and 25 °C was larger, which can raise the temperature of RDF and MBM more than 30 and 56 °C, respectively. Heat generation due to fermentation occurred and the temperature of RDF and MBM reached or exceeded 80 °C after 5 days for RDF and 4 days for MBM at 100% RH. The spontaneous ignition for RDF and MBM results from heat of wetting and fermentation at room temperature and a further exothermic reaction at higher temperature.     

Heat conduction, convection and radiolysis of the

A transportable water calorimeter for the determination of the quantity of absorbed dose to water in radiotherapy beams has been developed at the PTB and is presented in detail in this investigation. Heat conduction effects occurring in the calorimeter are studied for different lateral sizes of high-energy photon beams, for different depth dose distributions of electron beams and for a scanned-beam irradiation with a heavy ion beam. The corresponding correction factors are calculated and arguments are given under which conditions these can adequately be applied.     

Heat conduction effects during the calorimetric determination of absorbed dose to water in radiotherapy beams

A transportable water calorimeter for the determination of the quantity of absorbed dose to water in radiotherapy beams has been developed at the PTB and is presented in detail in this investigation. Heat conduction effects occurring in the calorimeter are studied for different lateral sizes of high-energy photon beams, for different depth dose distributions of electron beams and for a scanned-beam irradiation with a heavy ion beam. The corresponding correction factors are calculated and arguments are given under which conditions these can adequately be applied.     

Theoretical study on the molecule C30H20: five carbon–carbon single bonds linking a dodecahedrane cage and a pentaprismane cage

Using geometry optimization and DFT method at the B3LYP/6-31G* level of theory for C₃₀H₂₀, an equilibrium geometry is identified that has the form of polyhedral hydrocarbon with five carbon–carbon single bonds linking a dodecahedrane cage and a pentaprismane cage. Thus, this molecule is a tri-cage molecule with two pentaprismane cages and one dodecahedrane cage. Vibrational frequencies and the infrared spectrum are computed at the same level of theory. The heat of formation for C₃₀H₂₀ has been estimated in this paper. The heat of formation of C₃₀H₂₀ as well as the vibrational analysis indicates that this molecule enjoys sufficient stability to allow for its experimental preparation.     

Unsteady incompressible flow of magnetized aluminium oxide and titanium oxide nanoparticles with blood base fluid

In this investigation, a mixed convective nanoparticles fluid flow over an inclined plate is deliberated. The effects of slip boundary wall and magnetic field are also considered. The dimensionless governing system for the considered problem is attained by implementing recent definitions of fractional derivatives (FD). The generalized solution is obtained through the Laplace Transformation Scheme (LTS) for the momentum and thermal expressions. To improve the novelty and to demonstrate some more physical perception of the stated research work, some remarkable special cases of velocity distribution through CF and AB-fractional derivative concept are addressed, whose daily life implication is well known in the existing literature. Moreover, to evaluate the physical interest of the stated problem, the outcomes of the obtained system graphical illustrations are made by utilizing MATHEMATICA. As a result, we concluded that the aluminium oxide $A{l}_2{O}_3$ nanoparticles show more decaying behavior as compared to titanium oxide $Ti{O}_2$ nanoparticles for temperature and velocity profile. Furthermore, both fields i.e., momentum and thermal distributions are increased with the help of rising estimations parameter. Current results report novel applications in enhancement of heat transfer, thermal engineering, chemical processes, engineering and electronics devices, solar systems, extrusion processes, fission reactions etc.     

Sample evaporation in conventional GC split/splitless injectors. Part 1: Some quantitative estimates concerning heat consumption during evaporation

During sample evaporation in conventional vaporizing injection, the supply of heat to the evaporating liquid is a problem, first because the amounts of heat consumed are relatively large and, secondly, because the heat must be transferred to the sample within a very short time. Times available for evaporation, required amounts of heat, possible sources of heat, and the time required to transfer the heat to the sample liquid are discussed. It is shown that mixing with carrier gas contributes little heat to the evaporation process, but also that packings with glass wool have too low a heat capacity to deliver the required amount of heat to the evaporating sample. Transfer of heat from the insert wall to the sample easily requires several seconds, even if cooling of the vaporizing zone by 20° is accepted. Thus “flash evaporation” is usually impossible and most liquids must be held in the vaporizing chamber to allow full evaporation.     

Effect of phosphorus flame retardants on thermo-oxidative decomposition of cotton

The effect of six organophosphorus compounds, including Pyrovatex CP (PCP), diammonium phosphate (DAP), phosphoric acid (PA), tributyl phosphate (TBP), triallyl phosphate (TAP) and triallyl phosphoric triamide (TPT) on the flame retardancy of cotton cellulose was studied. PCP, PA, and DAP are more efficient compared with the other three compounds in improving the limiting oxygen index (LOI) of cotton. The effectiveness of these compounds was investigated using scanning electron microscope (SEM) images of char formed after LOI tests, char content, activation energy of decomposition and heat of combustion data. SEM images showed that DAP, PCP and PA chars maintain the surface morphology during the burning process, which might be due to the formation of a protective layer or crosslinking effect. PA, PCP, and DAP treated fabrics have a higher activation energy of decomposition, higher char content and lower heat of combustion.     

Thermodynamics of dimethylene urethane and poly(dimethylene urethane) in the range from T → 0 to 490 K at standard pressure

By high-precision dynamic calorimetry the temperature dependences of heat capacity of dimethylene urethane (DMU) between 320 and 370 K and partially crystalline poly(dimethylene urethane) (PDMU) in the range 326-490 K at standard pressure have been determined within ±1.5%. The thermodynamic characteristics of fusion of the substances, namely the temperature interval of melting, temperature, enthalpy and entropy of fusion, as well as the characteristics of devitrification and glassy state for poly(dimethylene urethane) have been estimated. The first and the second cryoscopic constants have been calculated for dimethylene urethane. The experimental data obtained in the present work and literature findings on the heat capacity of the substances were used to calculate their thermodynamic functions: the heat capacity C°_p (T), enthalpy H°(T)−H°(0), entropy S°(T) and Gibbs function G°(T)−H°(0) over the range from T→0 to (370-480) K. Based on the data, the thermodynamic characteristics of polymerization process with five-membered ring opening Δ_polH°, Δ_polS° and Δ_polG° of dimethylene urethane with the formation of linear partially crystalline poly(dimethylene urethane) have been evaluated.     

DSC study and computer modelling of the melting process in ice slurry

In order to understand the non-isothermal melting kinetics in the ice slurry, a differential scanning calorimetry (DSC) was used. Experimental results were compared to those obtained by a numerical simulation in which a general enthalpy method was applied. In this work the ice slurry studied consists of ice particles uniformly dispersed within a water-antifreeze liquid mixture. The effects of the heating rate and the initial antifreeze mass fraction are discussed. It has been found that the temperature gradients inside the sample of the solution become important if either heating rate increases or initial antifreeze mass fraction decreases.