Treatment of Phenol Wastewater Using High Gravity Electrochemical Reactor with Multi-concentric Cylindrical Electrodes

A novel high gravity electrochemical reactor with multi-concentric cylindrical electrodes was used in the electrochemical treatment of 5 000 mg/L phenol-containing wastewater at a petrochemical plant, which can operate continuously and process in a large scale. The results show that the high gravity technology used in electrochemical treatment of phenol-containing wastewater can shorten the electrolysis time, decrease the electrolysis voltage, and reduce the energy consumption. The COD removal efficiency was high in the high-gravity field, and reached up to about 48%, which was about 2 times the value achieved in the normal gravity field at a processing capacity of 6 L, a high gravity factor of 80, a voltage of 12 V, an electrolysis time of 40 min, and a wastewater flowrate of 80 L/h.

Medium Optimization for Improved Ethanol Production in Very High Gravity Fermentation

An optimal medium （300 g·L^-1 initial glucose） comprising 6.3 mmol·L^-1 Mg2＋, 5.0 mmol·L^-1 Ca2＋, 15.0 g·L^-1 peptone and 21.5 g·L^-1 yeast extract was determined by uniform design to improve very high gravity （VHG） ethanol fermentation, showing over 30% increase in final ethanol （from 13.1% to 17.1%, by volume）, 29% decrease in fermentation time （from 84 to 60 h）, 80% increase in biomass formation and 26% increase in glucose utilization. Experiments also revealed physiological aspects linked to the fermentation enhancements. Compared to the control, trehalose in the cells grown in optimal fermentation medium increased 17.9-, 2.8-, 1.9-, 1.8- and 1.9-fold at the fermentation time of 12, 24, 36, 48 and 60 h, respectively. Its sharp rise at the early stage of fermentation when there was a considerable osmotic stress suggested that trehalose played an important role in promoting fermentation. Meanwhile, at the identical five fermentation time, the plasma membrane ATPase activity of the cells grown in optimal medium was 2.3, 1.8, 1.6, 1.5 and 1.3 times that of the control, respectively. Their disparities in enzymatic activity became wider when the glucose levels were dramatically changed for ethanol production, suggesting this enzyme also contributed to the fermentation improvements. Thus, medium optimization for VHG ethanol fermentation was found to trigger the increased yeast trehalose accumulation and plasma membrane ATPase activity.

Degradation of Wastewater Containing Nitrobenzene by High Gravity-Ultrasonic/Ozonation/Electrolysis Technology

The integrated high gravity-ultrasonic/ozonation/electrolysis technology was applied in the pretreatment of wastewater containing nitrobenzene. The effect ofpH value, high gravity factor, liquid flow-rate and electric current density on removal of COD and nitrobenzene compounds was investigated. Experimental results have determined the optimal pro- cess regime involving a high gravity factor of 100, an electric current density of 20 mA/cm2, a liquid flow-rate of 100 L/h, and an initial liquid pH value of 11. After the wastewater had been treated for 180 rain, the degradation of nitrobenzene and COD reached 99% and 80%, respectively, with the biochemical coefficient （BOD/COD） equating to 0.64, and the subse- quent treatment of wastewater could be carried out by conventional biochemical means. Compared with traditional aeration- ozone contactors, a rotating packed bed with high mass transfer characteristics could be used to increase the ozonation treat- ment efficiency.

Study on Industrial Application of Hydrogen Sulfide Removal by Wet Oxidation Method with High Gravity Technology

The removal of hydrogen sulfide from gas plays an important role in rational utilization of resources and environ- mental protection. In this paper, the process of hydrogen sulfide removal by wet oxidation method in a rotating packed bed was investigated in a scale for treating 10 000 Nm3/h of gas. On the basis of studying the influence of the species and con- centration of alkali source, the liquid/gas volume ratio, the high gravity factor, and the hydrogen sulfide content in feed gas on the desulfurization effect, the suitable technological conditions were obtained. The hydrogen sulfide removal efficiency could reach 98.0% under these conditions. The results of continuous operation of process facilities showed that the high gravity method has many merits including higher desulfurization rate, good stability in operation, lower liquid/gas volume ratio, greater operation elasticity, and apparent energy saving effects.

Dynamics of vehicles with high gravity centre

The vehicles with high gravity centre are more prone to roll over. The paper deals with a method of dynamics analysis of fire engines which is an example of these types of vehicle. Algorithms for generating the equations of motion have been formulated by homogenous transformations and Lagrange＇s equation. The model presented in this article consists of a system of rigid bodies connected one with another forming an open kinematic chain. Road maneuvers such as a lane change and negotiating a circular track have been presented as the main simulations when a car loses its stability. The method has been verified by comparing numerical results with results obtained by experimental measurements performed during road tests.

Influence of EDTA on the Morphology of Barium Carbonate Using High Gravity Technology

The superfine BaCO3 particles were synthesized by high gravity technology with BaCl·2H2O and Na2CO3 as the raw materials. The changes of particle size and morphology were studied by adding different amount of EDTA, and rod-like, near-spherical and cylindrical shape BaCO3 were prepared. The BaCO3 particles were analyzed and characterized by TG/SDAT, SEM, XRD and FT-IR. The results indicated that the crystal transformation temperature and decomposition temperature of BaCO3 had increased because of EDTA addition. With the increase of EDTA amount, the shape of BaCO3 changed from irregular rod-like to near-spherical then to cylindrical shape. All different shape BaCO3 adopts orthorhombic crystal systems.

Sedimentation Process and Phase Transition of Solids Under High Gravity

The recent progress and future prospects for ultra-centrifugal sedimentation in solids are described,mainly involving equipment,miscible systems and compounds.Almost 90%ultracentrifugation experiments were performed on the 1st and 2nd high-temperature ultracentrifuge which is typically operated at temperatures below 500℃ under the maximum centrifugal acceleration up to 106 g.The strong gravitational and temperature fields induce atomic-scale graded structure,grain growth and refinement,and voids accumulation caused by the atomic sedimentation in miscible systems.New structures,properties and substances are produced in some compounds.A new cantilever high-temperature ultracentrifuge with a test temperature up to 1200℃ is under construction at Zhejiang University,making it possible to simulate the composition,microstructure and property evolution of superalloys in the operating environment of aircraft engines.

MASS PRODUCTION OF NANOPARTICLES BY HIGH GRAVITY REACTIVE PRECIPITATION TECHNOLOGY WITH LOW COST

Mass production of nanoparticles at low cost has attracted much attention from industrial and academic circles. In this paper, a novel method, the high gravity reactive precipitation (HGRP) technology, of manufacturing CaCO3 nanoparticles, presently scaled-up to an annual capacity of 10,000 tons, is presented. This paper describes the process principle, the process design and experiments on the syntheses of 15-30 nm CaCO3, 30-50 nm SiO2, 20-30 nm TiO2, 20-60 nm ZnO, 20-30 nm ZnS, 30 nm SrCO3, 40-70 nm BaTiO3, stick-like nano BaCO3 as well as nano-fibrillar aluminum hydroxide measuring 1-10 nm in diameter and 50-300 nm in length, using liquid-liquid, gas-liquid and gas-liquid-solid reactant systems. The advantage of using the HGRP technology is illustrated by comparison to conventional methods.

SYNTHESIS AND APPLICATION OF NANOPARTICLES BY A HIGH GRAVITY METHOD

Fast chemical reactions involved in nanomaterials synthesis, polymerization, special chemicals production, reactive absorption, etc., are often difficult to control in terms of product quality, process efficiency and production consistency. After a theoretical analysis on such processes based on chemical reaction engineering fundamentals, an idea to intensify micromixing (mixing on the molecular scale) and mass transfer and therefore to control the process ideally was proposed. By experimental investigations of mass transfer and micromixing characteristics in the Rotating Packed Bed (RPB, or 'HIGEE' device), we achieved unique intense micromixing. This led us to the invention of using RPB as a reactor for the fabrication of nanoparticles (Chen et al., 2000).

High-gravity-assisted green synthesis of rare-earth doped calcium molybdate colloidal nanophosphors

In this work,we report an innovative route for the synthesis of rare-earth doped calcium molybdate(CaMoO4)nanophosphors by using high gravity rotating packed bed(RPB)technology and paraffin liquid as the solvent.The significant intensified mass transfer and micromixing of reactants in the RPB reactor are benefiting for homogeneous doping of rare-earth ions in the host materials,leading to nanophosphors with high quantum efficiency.The use of liquid paraffin as the solvent eliminates the safety risks associated with volatile organic compounds,increasing the potential for clean production of nanophosphors.Under excitation of deep ultraviolet(DUV)light,the CaMoO4:Na+,Eu3+nanophosphors exhibit red emission at peak wavelength of 615 nm and quantum yield of up to 35.01%.The CaMoO4:Na+,Tb3+nanophosphors exhibit green emission at peak wavelength of543 nm with quantum yield of up to 30.66%.The morphologies of the nanophosphors are tunable from nanofibers through nanorods to nanodots and the possible mechanism of controlling the formation of different nanostructures is proposed on the basis of experimental results and theoretical analysis of mesoscience.These nanophosphors are highly dispersible in organic solvents and utilized for fabricating fabrication of flexible,freestanding luminescent films based on silicone resin.We also demonstrate the red LEDs consisting of the hybrid films of CaMoO4:Na+,Eu3+nanoparticles as color-converting phosphors and DUV LEDs as illuminators,offering strong potential for future nanophosphors-basedsolid-state lighting systems.

A new method of preparing high-performance high-entropy alloys through high-gravity combustion synthesis

A new method of high-gravity combustion synthesis(HGCS)followed by post-treatment(PT)is reported for preparing high-performance high-entropy alloys(HEAs),Cr0.9FeNi2.5V0.2Al0.5 alloy,whereby cheap thermite powder is used as the raw material.In this process,the HEA melt and the ceramic melt are rapidly formed by a strong exothermic combustion synthesis reaction and completely separated under a high-gravity field.Then,the master alloy is obtained after cooling.Subsequently,the master alloy is sequentially subjected to conventional vacuum arc melting(VAM),homogenization treatment,cold rolling,and annealing treatment to realize a tensile strength,yield strength,and elongation of 1250 MPa,1075 MPa,and 2.9%,respectively.The present method is increasingly attractive due to its low cost of raw materials and the intermediate product obtained without high-temperature heating.Based on the calculation of phase separation kinetics in the high-temperature melt,it is expected that the final alloys with high performance can be prepared directly across master alloys with higher high-gravity coefficients.

Optimization of High-Gravity Chelated Iron Process for Removing H_2S Based on Response Surface Methodology

By using a mixture of N2 and H2S as the simulated APG(associated petroleum gas), the desulfurization experiment was performed in a cross-flow rotating packed bed(RPB) based on the chelated iron oxidation-reduction method. In order to determine the operating conditions of the system, the effects of the concentration of Fe3+ ions(ranging from 0.1 to 0.2 mol/L), the liquid-gas volume ratio(ranging from 15 to 25 L/m3) and the high gravity factor(ranging from 36 to 126) on the removal of H2 S were studied by means of the Box-Behnken design(BBD) under response surface methodology(RSM). The overall results have demonstrated that the BBD with an experimental design can be used effectively in the optimization of the desulfurization process. The optimal conditions based on both individualized and combined responses(at a Fe3+ ion concentration of 0.16 mol/L, a liquid-gas volume ratio of 20.67 L/m3 and a high gravity factor of 87) were found. Under this optimum condition, the desulfurization efficiency could reach 98.81% when the H2 S concentration was 7 g/m3 in APG. In this work, the sulfur product was analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the energy dispersive X-ray spectrometer(EDX). The results of analysis show that the sulfur is made of the high-purity orthorhombic crystals, which are advantageous to environmental conservation.

Kinetics and mechanism of nitrobenzene degradation by hydroxyl radicals-based ozonation process enhanced by high gravity technology

This study investigated the indirect oxidation of nitrobenzene(NB)by hydroxyl radicals(·OH)in a rotating packed bed(RPB)using competitive kinetics method with p-nitrochlorobenzene as a reference compound.The rate constants of NB with·OH are calculated to be between(1.465±0.113)×10^(9)L/(mol·s)and(2.497±0.192)×10^(9)L/(mol·s).The experimental data are fitted by the modified Arrhenius equation,where the activation energy is 4877.74 J/mol,the order of NB concentration,rotation speed,and initial pH is 0.2425,0.1400 and 0.0167,respectively.The ozonation process of NB could be enhanced by RPB,which is especially effective for highly concentrated NB-containing waste-water under alkaline conditions.The high gravity technology can accelerate ozone mass transfer and self-decomposition of ozone to produce more·OH,resulting in an increase in the indirect oxidation rate of NB by·OH and consequently effective degradation of NB in wastewater.

Fusion bonding and microstructure formation in TiB_(2)-based ceramic/metal composite materials fabricated by combustion synthesis under high gravity

The novel ceramic/metal composite materials were successfully fabricated by combustion synthesis in high gravity field.In this paper,the Ti-B_(4)C was selected as the main combustion reaction system to obtain TiB_(2)-TiC ceramic substrate,and the 1Cr18Ni9Ti stainless steel was selected as the metal substrate.It was found that the TiB_(2)-TiC/1Cr18Ni9Ti composite materials exhibited continuously graded composition and hybrid microstructure.The TiC1-x carbides and TiB_(2)platelets decreased gradually in size and volume fraction from the ceramic to stainless steel.Due to the rapid action of thermal explosion as well as the dissolution of the molten stainless steel into TiB_(2)-TiC liquid,the diffusion-controlled concentration gradient from the ceramic liquid to the alloy liquid was observed.Finally,as a result of the rapid sequent solidification of the ceramic liquid and the melt alloy surface,the laminated composite materials were achieved in multilevel,scale-span hybrid microstructure.

Simultaneous saccharification and fermentation of sweet potato powder for the production of ethanol under conditions of very high gravity

Due to its merits of drought tolerance and high yield,sweet potatoes are widely considered as a potential alterative feedstock for bioethanol production.Very high gravity(VHG)technology is an effective strategy for improving the efficiency of ethanol fermentation from starch materials.However,this technology has rarely been applied to sweet potatoes because of the high viscosity of their liquid mash.To overcome this problem,cellulase was added to reduce the high viscosity,and the optimal dosage and treatment time were 8 U/g(sweet potato powder)and 1 h,respectively.After pretreatment by cellulase,the viscosity of the VHG sweet potato mash(containing 284.2 g/L of carbohydrates)was reduced by 81%.After liquefaction and simultaneous saccharification and fer-mentation(SSF),thefinal ethanol concentration reached 15.5%(v/v),and the total sugar conversion and ethanol yields were 96.5%and 87.8%,respectively.

Effects of Coexisting Substances on Nitrobenzene Degradation with O_3/H_2O_2 Process in High-Gravity Fields

This study used nitrobenzene as the simulated pollutant to study the effects of common inorganic sodium salts and organics on nitrobenzene degradation by O_3/H_2O_2 in high-gravity fields. The experiment results showed that the highgravity technology could increase the nitrobenzene removal rate by improving the ozone transfer efficiency and ozone dissolution. Coexisting substances had different effects on the degradation kinetics of nitrobenzene in high-gravity fields. Among such substances, Na_2CO_3, NaOH, Na_3PO_4, and NaNO_3 accelerated the removal of nitrobenzene. The main action principle of nitrobenzene degradation by O_3/H_2O_2 is that the additives can increase the pH value of the solution, stimulate ozonolysis, generate hydroxyl radicals(·OH), and improve oxidation efficiency. By contrast, NaCl, NaHCO_3, NaHSO_4, ethanol(C_2H_5OH), acetic acid(CH_3COOH), formic acid(HCOOH), and tert-butyl alcohol(TBA) inhibited nitrobenzene removal. When NaHCO_3, CH_3COOH, or HCOOH were added, the pH value of the solution decreased and free radical chain reactions were hindered. However, NaCl, NaHCO_3, C_2H_5OH, and TBA consumed ·OH radicals and inhibited nitrobenzene removal.

High-precision gravity correction methods for loess plateau areas, a case study

The loess plateau is featured by a sharply undulated and remarkably incised surface. The sharp surface undulation means great variation of loess thickness. Since the loess layer exhibits significant density contrast with the underlying formation, a high frequency gravity anomaly with a certain magnitude will appear. The high frequency gravity anomaly can result in some difficulties for processing and interpreting the gravity data, thereby reducing the usefulness of gravity surveys in loess plateau areas. We carried out a high precision gravity survey in the SHJZ structural zone. During data processing, we applied terrain and loess corrections to effectively remove or suppress the gravity effect resulting from surface undulation and variation of loess thickness. We obtained high precision gravity data which matches well with other geophysical data. The comprehensive interpretation based on the final gravity data help to study local structure integrated with other published geophysical data.

Variation of gravity before the Alxa Zuoqi M5.8 earthquake

In this study, a classic survey adjustment computation method was used for data obtained in the Inner Mongolia and Ningxia gravimetric networks between September 2013 and April 2015 so as to investigate the variation of gravity before the Alxa Zuoqi M5.8 earthquake. The relationship between gravity variation and the Alxa Zuoqi M5.8 earthquake was analyzed. The results showed that： （1） the severe variation in gravity field at the test sites before the Alxa Zuoqi M5.8 earthquake, as well as the subsequent accelerated rising, might be an earthquake precursor; （2） the Alxa Zuoqi M5.8 earthquake occurred at the turning point where the high-gravity gradient zone changed from the NE direction to NW.

Detection of Gravitational Waves with Semi Classical Features and Resulting Cosmological Implications

The author argues in this document that initial vacuum state values possibly responsible for GW generation in relic conditions in the initial onset of inflation may have a temporary unsqueezed, possibly even coherent initial value, which would permit in certain models classical coherent initial gravitational wave states. Furthermore, several arguments pro and con as to if or not initial relic GW should be high frequency will be presented, with the reason given why earlier string models did NOT favor low frequency relic GW from the big bang. What is observed is that large higher dimensions above our 4 Dimensional space time, if recipients of matter-energy from collapse and re birth of the universe are enough to insure low relic GW. The existence of higher dimensions, in itself if the additional dimensions are small and compact will have no capacity to lower the frequency limit values of relic GW, as predicted by Giovannini, et al. in 1995.

Study of damage to a high concrete dam subjected to underwater shock waves

To study the effect of a strong underwater shock wave on a concrete dam, this research aims to improve hammer impact methods in model tests. Six 1:200 scale models were designed and tested under distributed impact loads. A device was deployed for a direct measurement of the impact force at the upstream face of the dams. The model dam bases were anchored to prevent displacement. The experimental results indicate that the top part of the concrete dam is a weak zone, and the impact failure initiates with a fracture on the top of the dam. The peak value of impact stress increases when the second crack appears in the concrete dam from the upstream face to the downstream face. And, the level of the second crack in the dam body is lower as the peak value of impact stress increases. In this study, dynamic analysis was conducted by calculating the results to verify the effectiveness of a device to directly measure the impact force. This method may be used to approximately forecast the damage of concrete dam and may also be useful in other engineering applications.