Effects Of Technical Parameters Research Articles

Rhenium extraction from dilute solution by precipitation flotation and oxidative volatilization techniques

The low mass transfer effect of dilute solution results in low recovery efficiency of critical metal Re ions from ultralow-concentration metallurgical industrial effluents. Bubble driving was an effective measure to enhance the mass transfer in the dilute solution, and bubble flotation technology was adapted to enrich and recover metal ions. In this work, the extraction of critical metal Re from dilute solutions by a precipitation flotation process was investigated. The precipitation flotation process includes ion precipitation by CTAB and ammonium salt, flocculation by PAM and air bubble flotation separation. The effects of technical parameters on Re recovery were systematically investigated. In the precipitation stage, NH4+ with a positive charge firstly reacts with the rhenate (ReO4-) with a negative charge via electrostatic action and then further reacts with CTAB to form fine CTAB(NH4ReO4) precipitate through complexation coordination. In the flocculation procedure, the particle size of precipitate flocs is elevated due to the physical polymerization of PAM polymer. In the flotation procedure, the long carbon chains on the surface of the flocs have a foaming effect due to their strong hydrophobicity, and they are trapped by the upfloated bubbles and rapidly enriched in the foams. Under the optimized conditions, the recovery efficiency of Re is 99.5% and qualified circulating water with a turbidity of 9.8 is obtained. Eventually, highly purified Re oxides (99.8%) are prepared from the Re froth product via oxidizing volatilization since the utilized organic CTAB and PAM can be burned completely during the oxidizing calcination process.

Technical Parameters Selection on CT Scans Doses Used for Adult Diagnosis in Some Governmental Hospitals in Addis Ababa, Ethiopia

This study had assessed a technical parameters selection used on CT scan for adult diagnosis doses in Tikur Anbesa and Yekatit 12 specialized hospitals in Addis Ababa, Ethiopia. Data on Head, Chest, Abdomen-Pelvic, Abdomen, Brain, HRCT-chest, L-Sacral, and PNS scan regions were collected from a sample of 132. It was analyzed through descriptive statistics on Microsoft Excel 2016. The results were presented in the table, pie chart, line graph, and histogram. The parameter, Eff.mAs, pitch, table feed, and rotation time have strong correlations with CTDIvol, r(132) =0.749, α = 0.00, r (132) = -0.794, α = 0.00, r (132) = -0.708 α = 0.00, and r (132)=0.723, α = 0.00 respectively. Eff. mAs and DLP deviate by far from mean whereas KV, Rotation time, pitch and ED were almost nearly equal. The effects of technical parameters on doses descriptors agree on the theoretical facts, but for different scan regions 120KV was used. The dose descriptors of this study were greater than the studies in other countries. The medical technologist should have selected the appropriate KV based on scan regions. Relevant authorities should monitor the radiation management implementation in CT scan medical imaging procedure in hospitals where CT scan machines are employed.

Recovery of matte from copper slag by using rubber seed oil as green reductant

The traditional fossil reductant used in the copper slag cleaning process cannot fulfill the requirements of sustainable development of the copper industry and environmental protection. Therefore, a new approach of employing renewable rubber seed oil (RSO) instead of a non-renewable fossil reductant to clean copper slag (reduce magnetite concentration and improve matte recovery) was put forward in this study. The cracking characteristics of RSO at high temperature and the effects of technical parameters (such as reduction temperature, oil amount and settling time) on the copper loss, magnetite concentration and RSO utilization degree were thoroughly investigated. The results indicated that the cracking products of RSO at high temperature were mainly composed of C and H2. Under the conditions of a temperature of 1250 °C, an injection of 4 mL of RSO, and a settling time of no less than 1.5 h, the content of magnetite was reduced to less than 1 wt.%, and the content of copper in the upper level of the slag was lowered to be less than 0.57 wt.%, which met the criteria for discarding slag industrially. The copper slag cleaning by RSO is a process of carbon neutrality. The results provide a theoretic basis for the application of bioenergy in non-ferrous metal smelting process.

Optimisation of no-tube seeding and its application in rice planting

Current rice planting operations are mainly transplanting and direct seeding. However, many operational procedures involving transplanting use poor quality of machinery resulting in high labour costs and low working efficiency. Here a no-tube seeding (NTS) method is proposed and the effects of technical parameters (travel speed, seeding wheel rotational speed and ground clearance) on the seeding quality (accuracy, dispersion and uniformity) are investigated using a single factor bench test. A multifactor bench test was carried out to optimise the technical parameters based on the requirements of different seeding rate. The optimal value of the travel speed was constant at 0.80 m s−1 at different seeding rates, the optimised range of seeding wheel rotational speed and ground clearance is 17.5–23.53 r min−1 and 81.2–85.6 mm, respectively. A field experimental comparison between NTS, traditional tube seeding (TTS) showed that the seeding quality of NTS was significantly better than that of TTS. Compared with transplanting, rice growth status at booting stage for NTS and TTS was not significantly different with rows closed. However, the number of panicles per unit area was greater which was beneficial to the formation of high yield. The maximum and average yield of NTS increased by 10.1% and 6.7% compared with TTS and compared with transplanting it maximum and average yield increased by 11.6% and 9.3% respectively. These results indicate that NTS is feasible and efficient method.

Assessment of nano-hydroxyapatite and poly (lactide-co-glycolide) nanocomposite microspheres fabricated by novel airflow shearing technique for in vivo bone repair

A novel airflow shearing method was introduced to prepare microspheres efficiently with precisely control of microsphere size and homogeneity. The effects of technical parameters in the formation of the microspheres, such as solution concentration, nozzle size and airflow strength, were investigated. By optimizing the technical parameters (8% PLGA concentration, 27–32 G nozzle size, 6–8 l/min airflow strength), nano-hydroxyapatite and poly(lactide-co-glycolide) nanocomposite (nHA/PLGA) microspheres with a diameter around 250 μm and up to 40 wt% nHA content was prepared successfully. Especially, the microspheres possessed revealed great homogeneity and unique “acorn” appearance with two sides: A hard smooth side as well as a crumpled rough side, generated in the preparation process. Furthermore, the nHA/PLGA microspheres' potential application in bone tissue engineering was studied. In vitro, enhanced proliferation and osteogenic differentiation of the MC3T3-E1 cells was observed on as-prepared nHA/PLGA microspheres with high nHA content. In vivo, the BV/TV value of the microspheres with 20 wt% nHA was up to 75% and similar to the clinical products' performance. Moreover, beside high nHA content, the rough porous surface leads to bone ingrowth, which plays an important role in accelerating bone repair. Therefore, airflow shearing method could be an effective approach to fabricate biocompatible microsphere, and the as-prepared microspheres showed unique surface state and bone repair ability and making them as potential candidates for bone tissue engineering and bone implantation clinical applications.

A Study on the Effects of Technical Parameters on the Tensile Strength of Bamboo Plywood

The application of bamboo by-products such as bamboo branches, chips to recycle and produce pressed bamboo pulp is an urgent task in Vietnam. It perfectly replaces natural wood with artificial wood embryos from bamboo powder, which has both economic benefits of reserving the source of raw materials, environmental protection The paper presents a study on the influence of technological parameters on the tensile strength of pressed bamboo plastic fiber that is a new product of a project of our laboratory.

Microstructure Evolution in Magnesium Alloy ZK60 during Cyclic Extrusion and Compression

The microstructural evolution of of as-cast ZK60 magnesium alloy processed by cyclic extrusion and compression (CEC) were studied, and the effects of technical parameters on microstructural evolution were investigated. The results show that the grains of as-cast ZK60 magnesium alloy were obviously refined and uniformed by CEC, the average grain size was decreased from original 50 ~ 60 μm to about 2 μm when the extrusion ratio was 8 with 8-passes at 350°C, and the refinement effect was increased with the rising of extrusion ratio and passes. The effect of increasing passes on grain refinement was not obvious when it exceeds 8. Nevertheless, it is beneficial for the grain homogenization.

Effects of Technical Parameters on Mechanical Expanding of Large Diameter Welding Pipe

Mechanical expanding is widely used in production of large diameter submerged-arc welding pipes. The pipe is circumferentially expanded to obtain a highly circular shape. But the crack of the metal material often happens under the action of the expanding load. To analysis this problem, it is necessary to analysis the distribution of stress in mechanical expanding forming process. So, mechanical expanding is analyzed using finite element method. Taking the expanding of X80 steel Φ1219mm×22mm×12000mm welding pipe for instance, the mechanical expanding forming process is simulated by finite element (FE) code ABAQUS. In this paper, the simulation data is validated by experiments and a comparison showed a good agreement with experiments results. The maximum mises stress of mechanical expanding is discussed. Thus, the result of research provides a basis to improve welded pipe quality.

Sensitivity Analysis of Technical Parameters on Springback in Air Bending of JCO Forming

JCO forming is one of manufacture mode widely used in production of large diameter submerged-arc welding pipes, in which JCO forming process is progressive multi-step air bending. In order to design technical parameters, it is necessary to analysis effects of technical parameters on springback in air bending of JCO forming. So, sensitivity analysis of technical parameters on springback in air bending of JCO forming is carried out using finite element method. Taking the air bending of X80 steel Φ1219mm×22mm×12000mm welding pipe for instance, the air bending is simulated by finite element (FE) code ABAQUS. In this paper, the simulation data is validated by experiments and a comparison showed a good agreement with experiments results. The sensitivity analysis of technical parameters from simulation is discussed. Thus, the results of research provides a basis to design technical parameters.

Effects of Technical Parameters on Process Stability and Microstructure during Continuous Rheo-Extrusion Process of 6201 Alloy Wire

In this paper, effects of technical parameters on process stability and microstructure during continuous rheo-extrusion process of 6201 alloy wire were investigated. The optimal process parameters for producing 6201 alloy wire are obtained. The casting temperature is from 720°C to 740°C, and the roll rotating speed is 15r/min. The 6201 alloy wire with good performance has been successfully manufactured. After heat treatment, the tensile strength of the product reaches 325 MPa and the resistivity reaches 32.47 nΩm, which is better than LHA2 conducting wire of China.

Mechanical Properties of the Regenerated Rubber Prepared by Waste Tire Powders and Fillers

Waste tire powder (WTP) was reclaimed mechanically in presence of a new composite additive which consists of reinforcing materials (RM) and toughening materials (TM), and the effects of technical parameters and additives were investigated. According to the orthogonal experiments and the range analysis, the final ranking of the significance of factors in tensile properties was determined to be as follows: TM content > curing temperature > sulfur content > TBBS content > RM content (for tensile strength) and sulfur content > curing temperature > TBBS content > TM content > RM content (for elongation at break). The optimal conditions for tensile strength and elongation at break were determined respectively. Tensile strength and elongation at break tended to decrease after an initial ascent with the RM content increased. An apparent ascent of elongation at break was observed as TM content increases. Tensile strength increased first, and then decreased.

Effects of Technical Parameters on Initial Silicon Melting in Round Cold Crucible Continuous Casting

The effects of technical parameters on initial silicon melting in cold crucible continuous casting were studied. These parameters include the materials, the shape and the position of the base, the mass of the silicon that set on the top of the base. Through experimental and theoretical analysis, the optimized parameters were finally given: the base graphite with obconical shaped should be put at the level of the second turn of the coil, and the initial silicon with 10g should be put on the base. The mechanism of these parameters affecting on the initial melting are discussed and revealed.

Experimental study on surface quality of silicon ingots prepared by electromagnetic continuous casting

The effects of technical parameters on the forming of surface defects of the silicon ingots prepared by electromagnetic continuous casting were investigated by the orthogonal experiment, and the corresponding defect formation mechanisms were discussed and established. The results indicate that the forming of the ripple and lap are mainly caused by the shrinkage of shell and controlled by the electromagnetic pressure, and the unmelted granules are those moving from the center to the edge on the liquid surface, which was directly cooled by the cold crucible wall and kept as unmelted state. The surface quality was shown to be significantly improved by increasing the input power, pulling velocity and the heat preservation time, and among them, the input power is the most important one.

Preparation and Characterization of Hydrophilic PVDF Membrane via Graft Modification by Acrylic Acid

Hydrophilic polyvinylidene fluoride (PVDF) flat ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of acrylic acid grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated, the technical parameters of preparation of hydrophilic PVDF membranes were determined, and hydrophilic PVDF flat membranes were prepared. Then, hydrophilic PVDF membranes were characterized in terms of pure water flux, contact angle, infrared spectroscopic analysis and scanning electron microscope (SEM). The results showed that acrylic acid had been grafted onto PVDF, and the hydrophilic performance of the modified membrane was better than the traditional one.

Preparation and Characterization of Hydrophilic PVDF Membrane via Graft Modification by Maleic Anhydride

Hydrophilic polyvinylidene fluoride (PVDF) flat ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of maleic anhydride grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated, the preparation technical parameters were determined, and the hydrophilic PVDF flat membranes were prepared. Then, hydrophilic PVDF membranes were characterized in terms of pure water flux, contact angle, infrared spectroscopic analysis and scanning electron microscope(SEM). The results showed that maleic anhydride had been grafted onto PVDF, and the hydrophilic performance of the modified membrane was better than the traditional one.

Study the optimum parameters of high voltage electrostatic field thawing

To improve the thawing technique and the thawing efficiency of high voltage electrostatic thawing, reducing the energy consumption, the effects of technical parameters on the thawing rate and energy consumption were investigated. Ice contained in the Petri dish was put in the high voltage electrostatic field which was made up of a multiple point pole and a plate pole. By changing the thawing voltage, the electrode spacing and the distance between the two neighboring needles, the factors related to the thawing rate and energy consumption were quantitatively studied. The results indicate that when the distance between the needle electrodes and the surface of the plate pole is constant, the thawing rate increases linearly while the thawing energy consumption increases nonlinearly with the supplied voltage. When the supplied voltage is not changed, the ice thawing rate and energy consumption are changed with the distance between the two neighboring needles. When the distance between the two neighboring needles is not changed, the ice thawing rate and energy consumption are changed with the electrode spacing. When the electrode spacing is 9cm, the thawing rate is the highest while the energy consumption is relative least, 45kV is the optimum value for thawing voltage.

Effects of Technical Parameters on the Phase Composition and Microstructure of Yb α-SiAlON Prepared by Combustion Synthesis

In this paper, Yb a-sialon powders with elongated grains have been prepared by combustion synthesis. The effects of diluents, nitrogen pressure, adding a-sialon seeds and NH4F on the phase transformation and microstructure development of the samples are discussed systematically. The experimental results show that the addition of diluents, proper nitrogen pressure and additive NH4F can facilitate the nitridation of Si. It was also found that the added a-sialon seeds and NH4F are beneficial to the nucleation and growth of elongated grains.

EFFECTS OF TECHNICAL PARAMETERS ON THE PULSED LASER DEPOSITED FERROELECTRIC FILMS

Pulsed laser deposition (PLD), which is a novel technique in producing thin films in the recent years, shows unique advantages for the deposition of ferroelectric films. Effects of technical parameters on the pulsed laser deposited ferroelectric films, including substrate temperature, oxygen pressure, post-annealing, buffer layer, target composition, energy density, wavelength, target-to-substrate distance, and laser pulse rate, are systematically reviewed in order to optimize these parameters. Processing-microstructure-property relationships of ferroelectric films by PLD are discussed. The application prospect is pointed as well.