Modification of technology and aerodynamics of moving hot bulk materials

Variants of pneumatic transport with temperature data of the material are given. Methods for protecting the container from thermal heating are listed. An unloading device for cargo containers for pipeline transport of hot bulk materials has been developed. The proposed system of two integral equations will make it possible to calculate with sufficient accuracy the required compressed air pressure, geometric parameters of aerodynamic ridges for a given length of the unloading section of rotating containers and their translational speed. The presence of aerodynamic ridges will reduce the loss of energy from friction when moving containers in a spiral.

Numerical design and studies of multipurpose concentrated solar thermal heating system

Solar thermal energy systems are future sustainable solutions for both domestic as well as industrial use. Solar thermal systems operating in medium temperature range (373-673 K) require concentrated solar-thermal heating (CSH). In this work, a comprehensive numerical tool is developed to design and study multipurpose on-sun CSH system. The model uses a combined Monte-Carlo ray tracing, finite difference method and all heat transfer modes. The model is validated with in-house experiment, which demonstrates its predictive capability. Next, the tool is used to optimise the cavity receiver geometry and predict the performance of the optimised CSH system under different direct normal irradiance (DNI) conditions. A CSH system using Therminol D12 as HTF is presented. Therminol D12 HTF based system is predicted to take longer time than the system using water as HTF, for heating water to a specified temperature because of the heat exchanger effectiveness. However, the designed CSH system using Therminol D12 can attain higher temperatures than water without pressurization and through the heat exchanger can be used as multipurpose system suitable for cooking, laundry, sterilization, process industry etc.

Ultra-fast Cu-based A3-coupling catalysts: faceted Cu2O microcrystals as efficient catalyst-delivery systems in batch and flow conditions

Cu(I) catalysts were studied for the synthesis of a propargylamine via A3-coupling of aldehyde, amine, and alkyne, under solvent-free and low loading conditions, using batch microwave or flow thermal heating. We explore ultra-low loading conditions with Cu(I) salts as ultra fast and active catalysts featuring TOFs above 105 h-1. Well-defined octahedral and cubic Cu2O microcrystals were also successfully applied and compared to this reaction. Both types of microcrystals exhibited excellent catalytic activities within minutes, via in-situ generation of low dose of Cu(I) ions within the reaction medium, to achieve TON beyond 2000 and recycling up to 10 times in a flow reactor. The study of the catalytic system demonstrated that the activity was surface-structure dependent and allowed for the design of low Cu contamination A3-coupling systems, affording a product at the decigram scale, with Cu contamination below FDA recommendations for drug synthesis, without the need for a purification procedure.

Microwave-assisted photooxidation of sulfoxides

We demonstrated microwave-assisted photooxidation of sulfoxides to the corresponding sulfones using ethynylbenzene as a photosensitizer. Efficiency of the photooxidation was higher under microwave irradiation than under conventional thermal heating conditions. Under the conditions, ethynylbenzene promoted the oxidation more efficiently than conventional photosensitizers benzophenone, anthracene, and rose bengal. Ethynylbenzene, whose T1 state is extremely resistant to intersystem crossing to the ground state, was suitable to this reaction because spectroscopic and related reported studies suggested that this non-thermal effect was caused by elongating lifetime of the T1 state by microwave. This is the first study in which ethynylbenzene is used as a photosensitizer in a microwave-assisted photoreaction.

INFLUENCE OF SURFACE PRE-HEATING ON THE NITRIDING DEPTH OF STEEL 25CrMoVA USED COMPLEX ION-PLASMA TREATMENT

In the method of nitriding elements, various methods of their thermal heating are used. The simplest heating method in ion-plasma nitriding is heating by bombarding the surface first with low-energy gas ions and then with metal ions with energies up to several kiloelectronvolt. Elements exposed to ion bombardment have a welldeveloped surface that is free from contaminants and facilitates the diffusion of nitrogen into the depth of the metal during nitriding. The paper studies the effect of various preliminary heating methods on the nitriding depth in the complex ion-plasma hardening technology of 25CrMoVA steel. A JSM 7000-1F scanning electron microscope equipped with an X-ray spectral energy dispersive microanalysis attachment was used to diagnose changes occurring on the surface of the samples and at depth; the hardness was measured using a Nanoindentor G200 device. The preliminary heating of the samples was carried out both with the use of bombardment with Ti or Mo ions, and without its direct effect on the heated surface. In the experiment, differences in the depth of hardening of the nitrided layer of steel are observed when it is heated in different ways. When bombarded with Mo ions, the greatest depths of hardening were obtained in comparison with other preliminary heating conditions. It is shown that these differences are associated with the features of the morphology of the steel surface formed as a result of sputtering processes. The formation of nitride compounds in its surface layer can serve as a barrier that slows down the penetration of nitrogen into the metal. It is shown that with complex treatment in the process of deposition of a nitride coating on the surface of nitrided steel, an additional increase in the depth of hardening of the nitrided layer occurs.

A Comparative Study of Fabricating IrOx Electrodes by High Temperature Carbonate Oxidation and Cyclic Thermal Oxidation and Quenching Process

IrOx electrodes were fabricated by cyclic thermal heating and water quenching (CHQ) process and high temperature carbonate oxidation (HCO), respectively. By examining the E-pH relationship, response rate, potential drift behavior of the fabricated electrodes, the electrodes prepared by CHQ process seemed to show better comprehensive performance. Characterization tests such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS) were used to characterize the fabricated IrOx electrodes and find out the reason for the better performance of the electrodes prepared by CHQ process. Morphology tests indicate that the CHQ electrode shows a multi-layer structure with more ion channels, which could provide larger surface area for the H+ response process. Furthermore, combining the XPS, Raman and EIS tests etc., more effective response composition, better crystal quality, and smaller response reaction resistance of surface IrOx film could account for the better performance of the CHQ-fabricated IrOx electrode. The film formation process, H+ response mechanism, as well as the response behavior difference between the two kinds of the electrodes are further elaborated.

Impacts of Thermal Heating Phosphogypsum on the Physiochemical Properties of Blast Furnace Slag Cement

Within approximately 50 years, 1.0 × 108 tons of Phosphogypsum have already been produced and collected. Nearly 85 percent PG byproduct has been stored, only15 percent has been reprocessed. Lowering disposal of waste materials offers both environmental and economic advantages. Physical and chemical characteristics of Blast furnace slag cement after partial and full replacing of raw gypsum with samples prepared from BFSC-PG at various temperatures (200–1000°C) are formed by blending different proportions with PG have been studied. The results validated the application of calcined Phosphogypsum at 800 and 1000 degrees Celsius rather than raw gypsum in cement manufacturing.