Energy Input Mode Research Articles

Effects of energy input modes on energy efficiency and berry quality in continuous microwave drying

To elucidate the effects of energy input modes on energy efficiency and berry quality in continuous microwave drying, four energy input modes with variational working ways of magnetrons were investigated by using numerical simulation and bench experiments in a continuous microwave dryer. Energy efficiency was divided into absorption and conversion efficiency to study the change rule of drying process, and the retention rate of anthocyanins of berry’s representative nutrition ingredient was studied considering both of the temperature and its uniformity. Results indicate that the energy input modes affect the absorption efficiency by changing the distribution uniformity of electric field of material layer, and the conversion efficiency by altering the matching degree between the energy allocation and drying characteristics of berry, which are both determined by the ways of working magnetrons of different energy input modes. The conversion efficiency has a greater influence on the final energy efficiency, so the energy input mode should be paid attention to the provision of microwave energy by selecting proper way of working magnetrons according to the drying characteristics. The effect of temperature uniformity on anthocyanin degradation is more obvious with average temperature increasing gradually, where better uniformity of electric field strength should be provided to guarantee the quality of dried berry by adjusting the energy input mode. The research results provide significant insights to optimize the energy input mode of taking into account both the energy efficiency and dried quality of material.

Control of a high-voltage discharge-pulse installation when implementing technological modes of an electrochemical explosion

Studying the high-voltage electrochemical explosion as a control object has established a significant impact exerted by the modes of controlled energy input into a discharge channel on the efficiency of exothermal energy conversion. Dependence has been derived of the specific energy efficiency of the release of chemical energy by an exothermic mixture on the distribution of the total introduced electrical energy among successive discharge pulses. This has made it possible, based on the rules proposed here, to determine the initial conditions for the control algorithm of a discharge-pulse installation, which implements the high-voltage electrochemical explosion technological modes, providing maximum effectiveness of exothermal transformations.It has been shown that the considerable stochasticity of processes during exothermal transformations under a mode of explosive combustion does not make it possible to use control systems that regulate only the initial conditions for an electrochemical explosion. Such systems do not ensure the preset discharge modes at each implementation. The need for ongoing control over the process of exothermal transformations has been substantiated, in order to prevent the reduction of pressure in a discharge channel below the allowable value that maintains the exothermic reaction of explosive combustion. The performed correlation analysis of the relationship between the values of current pressure in a discharge channel and the discharge electrical characteristics has revealed that there is a dense enough information interrelation between them. Therefore, it has been proposed to use, as the information signals that indirectly determine the pressure in a discharge channel, the operationally defined electrical characteristics of a discharge.An algorithm has been built and a system has been developed to control a high-voltage discharge-pulse installation that implements a high-voltage electrochemical explosion. Control over the mode of energy input in the process of explosive transformation makes it possible to avoid the extinction of the exothermal reaction at an accidental, due to the stochasticity of the process, reduction in pressure to the maximum allowable value in the period between the discharge pulses. Due to this, the unproductive losses of an exothermic mixture are eliminated, the losses of chemical and electrical energy are reduced, and the amount of total energy released is increased, without increasing the introduced electric energy, at each implementation of a high-voltage electrochemical explosion

The energy input mode influence on the efficiency of plasma water treatment in a bubble chamber

The optimal time interval was found for plasma treatment of liquid using distilled water as an example. The positive effect of plasma-active water on the agricultural crops growth is shown. The synchronization task of chemically active particles formation and their entry into the liquid has been revealed.

Influence of process parameters on the correlation between in-situ process monitoring data and the mechanical properties of Ti-6Al-4V non-stochastic cellular structures

Selective Laser Melting (SLM) facilitates the formation of complex, stochastic or non-stochastic, metallic cellular structures. There is a high level of interest in these structures recently, particularly due to their high strength to weight ratios and osteoconductive properties. While the ability to in-situ monitor the SLM process is of key importance for future quality control methods.In this work lattice structures were fabricated, using the single exposure scanning strategy, on a Renishaw 500M SLM machine. The build process was also monitored using a co-axial in-situ process monitoring system.It was found that by increasing the energy input, through increasing the laser power and/or exposure time, the lattice strut diameters, within the 1.5 mm diamond unit cells, increased from 119 to 293 μm, resulting in the major pore diameter decreasing from 1106 to 932 μm. The effect of systematically altering the laser beam spot size on the cellular structures was also evaluated. It was observed that by doubling the laser beam spot size, that there was a 17% reduction in strut diameter and a 22% reduction in mechanical strength of the structures. It was also observed that at constant energy input levels, the lattice structures created using a focused laser exhibited an 81% lower mechanical strength than the structures created using a de-focused laser. Thus, demonstrating that the mode of energy input is critical to achieving the desired strength in these structures.Based on the outputs from the in-situ monitoring system, a broadly linear correlation was obtained between the laser input energy, the associated process monitoring data generated and the mechanical strength of the lattice structures.

Vibration at structural resonance frequency of hydrophilic substrates enhances biofilm removal

Biological fouling damages both human health and industry by causing infection, corrosion, structural failure, and drag on marine ships. Current efforts to clean bio-fouled surfaces by externally applying intensive mechanical energy often result in relapsed cell growth. Therefore, this study examines the extent that cell-structure interactions are orchestrated by vibration frequency, voltage-induced energy input mode, and surface energy to clean bio-fouled surfaces. This study was conducted with a tough polyacrylamide gel-coated polypropylene substrate attached to a flexible dielectric actuator that can vibrate when an oscillatory voltage is applied. We found that the maximum biofilm removal occurs by vibrating the gel-coated surface at the structural resonance frequency using a square wave input voltage. In addition, tuning the surface energy of the substrate was necessary for biofilm removal by decreasing the bacterial adhesive force. The findings from this study can be broadly applicable to assembling various advanced anti-fouling medical and industrial devices.

Effects of Energy Input on the Laboratory Column Flotation of Fine Coal

This study explored the effects of energy input and different energy increase patterns on the separation performance of a laboratory cyclonic–static microbubble flotation column in fine coal flotation. The energy input was changed by adjusting the circulating pump power and pulp residence time. Continuous flotation tests were designed by using five feed rates (i.e., different pulp residence time), which were 53.33, 80.00, 106.40, 133.60, and 160.00 g/min, and various useful power of the circulating pump (22.44, 30.14, 38.50, 46.86, 56.10, and 64.46 W). Results show that concentrate combustible recovery initially increased before reaching saturation distribution with increasing energy input absolute value. An ash content of 10.90% and combustible matter recovery of 92.84% were obtained at the energy input of 10098.00 J which is called the flotation saturation energy Es. Es is the essential condition and guarantee for a complete flotation process. A low ash content of clean coal was obtained with low energy input. With the increase of energy consumption, the additional coals recovered were coarse particles with low ash content and fine particles with high ash content. However, the ash content did not exhibit a significant change with the increase of energy input in this investigation. During the flotation process, a minimum critical flotation time T and critical circulation pump useful power P are required. If the P and T of a variable are less than the critical value, high combustible matter recovery could not be obtained by adding another variable to increase energy input. A reasonable mode of energy input was proposed that the absolute value of the energy input reaches Es; meanwhile, it ensures that each value of the P and T is greater than the critical values.

A New Technique for Removing Unburned Carbon from Coal Fly Ash at an Industrial Scale

Removal of unburned carbon from the high-carbon fly ash (HCFA) is essential when it is used as an admixture in cement concrete. This article deals with processing of the HCFA from the Guangdong province of China. A cyclonic-static microbubble flotation column (FCSMC), a novel device with the characteristics of internal recycling process and multiple mineralization steps, was used to separate unburned carbon from ash materials. A commercial flotation plant with a handling capacity of 110 ton coal fly ash (dry basis) per hour was set up. Using the optimum operational parameters, a clean ash with loss on ignition (LOI) of 3.08% and a removal rate of unburned carbon (RUC) of 80.41% was obtained. The calorific value of the unburned carbon products reached 3534 cal/g. Industrial-scale flotation tests on the circulation pulp pressure demonstrated that the energy input mode and internal recycling process of FCSMC separator was effective in removing unburned carbon from HCFA.

Evaluation on Thermal Adjusting Effect of PCM Cooling Vest by Thermal Manikin

Abstract. In this paper the hot steel work environment is simulated and a thermal manikin is utilized to evaluate the thermal adjusting effect of a cooling vest incorporated with PCM packs of gel. Two control modes of the thermal manikin, the constant energy input mode and the constant skin temperature mode are used respectively to evaluate the cooling vest’s thermal adjusting effect. The experiment demonstrates that the cooling vest can alleviate the manikin’s skin temperature. When the constant energy input control mode is used, the manikin’s body parts covered by PCMs have lower skin temperature than other body parts; When the constant skin temperature mode is used, the manikin’s chest and back part, followed by the abdomen and buttocks part have the highest energy cost.

Formation of a spall cavity in a dielectric during electrical explosion

The wave dynamics of the stress-strain state of a solid dielectric during electrical explosion near its surface is analyzed. A quantitative model of an electrical explosion is developed which describes the operation of a high-voltage generator, the expansion of the discharge channel, and the generation and distribution of shock-wave perturbations. Two mechanisms of formation of a spall cavity on the surface of the solid are considered: the less energetic mechanism implemented by means of the waves reflected from the surface, and the more energetic mechanism in which result from the action of a direct wave of compressive stresses. The effects of the reflection surface shape and the mode of energy input into the channel on the possible fracture pattern are estimated.

Influence of laser energy input mode on joint interface characteristics in laser brazing with Cu-base filler metal

The flange butt joints of 1 mm-thick galvanized steel sheets were brazed with CuSi3 as filler metal at different laser heating modes. The microstructures and element distributions of joint interface were investigated by SEM and EDS. The results show that there is no obvious interface layer with the circular individual beam heating and lamellar Fe-Si intermetallic compound layer is found with dual-beam laser spot heating. With the irradiation of rectangular laser spot, the joint interface layer is also formed. The layer thickness is larger than that of dual-beam brazing and the layer shape is flat so that intermetallic compounds trend to grow into cellular crystals. Moreover, the interface layer shape also depends on its position in the joint. Under the high heat input, dendritic or granular intermetallic compounds dispersively distribute in brazing seam adjacent to the interface, which is caused by the melting or dissolving of the base metal. According to the results, the brazing quality can be controlled by laser heating mode and processing parameters.

Laser processing of a SiC/Al-alloy metal matrix composite

Preliminary studies were conducted on the laser processing of SiC/A356-Al alloy metal matrix composite (MMC) for such applications as welding/joining and cutting. The SiC/A356-Al MMC was processed using several different laser specific energies. Microstructural observations after laser processing revealed that the extent of reinforced material (SiC)-matrix (A356-Al) reaction is directly proportional to the laser energy input. As energy input increased, SiC particle dissolution became greater and aluminum carbide formation increased in both size and quantity. It appears possible to control substantial change (physical and chemical) in SiC particles during processing by controlling the amount and mode of energy input.

An experimental investigation of variable energy blast waves

The results of an experimental investigation of spherical blast waves are reported. Shock trajectories and flow field densities are compared with approximate and/or numerical predictions. The numerical predictions are based upon a finite difference formulation of the conservation equations in Lagrangian coordinates. Experimentally, blast waves in air and chloroform have been induced by focusing the output of a high energy pulsed ruby laser onto a flat target to form a hemispherical field. Both Q-switched and open lase output were used. The open lase mode results in an approximation of linear energy input. Flow field data were obtained during and subsequent to the energy input interval using a Mach-Zehnder interferometer in conjunction with a high speed rotating mirror framing camera. Shock trajectories in the form of radius-time ( R- t) plots were obtained from the camera records. These shock trajectories were found at early times to follow similarity predictions of R ∼ t 2/5 for instantaneous energy input and R ∼ t 3/5 for linear energy input, while at later times they tended to follow the approximate/numerical predictions. Radial density profiles, obtained from interferometric records through Abel integral inversion techniques, agreed with the following predictions. Starting at the shock front and progressing radially inward, it is predicted that for instantaneous energy input, the density decreases rapidly at first and gradually thereafter, asymptotically approaching zero at the blast wave center. Conversely, for the linear energy input mode, the density initially decreases gradually, but then the gradient steepens and the density rapidly approaches zero close to the shock front, thus forming a shell-like region near the shock front.

Effect of parameters of the discharge circuit on the mode of energy input into the gas in a self-sustained discharge

A model is proposed for calculating the characteristics of volumetric gas discharges used in the pumping of electric-discharge lasers. The dependence of the mode of energy input into the plasma of the gas discharge on the parameters of the discharge circuit is discussed.