Co-composting of poultry manure and rubber wood sawdust was performed with the ratio of 2：1（V/V） for a period of 60 days. An investigation was carried out to study the extracellular enzymatic activities and structu...Co-composting of poultry manure and rubber wood sawdust was performed with the ratio of 2：1（V/V） for a period of 60 days. An investigation was carried out to study the extracellular enzymatic activities and structural degradation utilizing Fourier transform infrared spectroscopy（FT-IR）, thermogravimetry and differential thermal analysis（TG/DTA）and scanning electron microscopy（SEM）. The microbial succession was also determined by using denaturing gel gradient electrophoresis（DGGE）. The compost was able to reach its highest temperature of 71°C at day 3 and stabilized between 30 and 40°C for 8 weeks.CMCase, FPase and β-glucosidase acted synergistically in order to degrade the cellulosic substrate. The xylanase activities increased gradually during the composting and reached the peak value of 11.637 U/g on day 35, followed by a sharp decline. Both Li P and Mn P activities reached their peak values on day 35 with 0.431 and 0.132 U/g respectively. The FT-IR spectra revealed an increase in aromaticity and a decrease in aliphatic compounds such as carbohydrates as decomposition proceeded. TGA/DTG data exhibited significant changes in weight loss in compost samples, indicating degradation of organic matter. SEM micrographs showed higher amounts of parenchyma exposed on the surface of rubber wood sawdust at day 60, showing significant degradation. DGGE and 16 S r DNA analyses showed that Burkholderia sp., Pandoraea sp., and Pseudomonas sp. were present throughout the composting process. Ornithinibacillus sp. and Castellaniella ginsengisoli were only found in the initial stage of the composting, while different strains of Burkholderia sp. also occurred in the later stage of composting.展开更多
Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid （IL） 1-butyl-3-methyl-imi-dazolium hydrogen sulfate （[bmim]HSO4） at ambient pressure in the presence of hy...Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid （IL） 1-butyl-3-methyl-imi-dazolium hydrogen sulfate （[bmim]HSO4） at ambient pressure in the presence of hydrogen peroxide （H2O2） and potassium peroxymonosulfate （oxone） as the oxidants. Parameters affecting leaching efficiency, such as dissolution time, IL concentration, and oxidizing agent addition, were investigated. The results show that [bmim]HSO4 is an efficient IL for the brass ash leaching, providing the dissolution efficiencies of 99%for Zn and 24.82%for Cu at a concentration of 50vol%[bmim]HSO4 in the aqueous solution without any oxidant. However, more than 99%of zinc and 82%of copper are leached by the addition of 50vol%H2O2 to the [bmim]HSO4 solution. Nevertheless, the oxone does not show the promising oxidant behavior in leaching using [bmim]HSO4.展开更多
Collagenase was isolated from fish waste (a mixture of haddock, herring, ground fish and flounder) using a Tris-buffer system. The proteins in the crude extract were precipitated using ammonium sulfate (40% - 80%) and...Collagenase was isolated from fish waste (a mixture of haddock, herring, ground fish and flounder) using a Tris-buffer system. The proteins in the crude extract were precipitated using ammonium sulfate (40% - 80%) and purified with gel-filtration chromatography using Sephadex G-100. The results showed that the collagenase enzyme was produced as a latent enzyme and was activated with bovine trypsin and potassium thiocyanate (KSCN). The enzyme activity was affected by pH and temperature. Optimal enzyme activities were found at 35?C and a pH of 7.5 when insoluble collagene type I was used as substrate and the liberated amino acids were measured in relation to L-leucine in the presence of ninhydrin. The enzyme activity was completely inhibited by the action of ethylenediaminetetraacetic acid (EDTA) suggesting that the collagenase enzyme isolated from the fish waste is a metalloproteinase enzyme requiring metal ions for enzyme activity. Dialysis against KSCN decreased the enzyme total activity and increased its specific activity. Sodium dodecyl sulphate polyacryla-mide gel electrophoresis (SDS-PAGE) indicated that the purified procollagenase enzyme have only one band at molecular weight of 50 kilodaltons (kDa). When the enzyme was cleaved with trypsin, it was found to consist of two subunits: a large unit with a molecular weight of 50 kDa and a small unit with a molecular weight of 10 kDa.展开更多
A rapid, specific, sensitive, and precise reverse-phase HPLC method for the quantitative determination of process related and degradation impurities of Apixaban, an anticoagulant drug is described. The developed RP-HP...A rapid, specific, sensitive, and precise reverse-phase HPLC method for the quantitative determination of process related and degradation impurities of Apixaban, an anticoagulant drug is described. The developed RP-HPLC method was successfully applied to the analysis of both Apixaban drug substance and drug product. The chromatographic separation was achieved on a Sigma-Aldrich’s Ascentis Express®C18 (4.6 mm × 100 mm, 2.7 μ) HPLC column with a runtime of 40 min. Mobile phase-A and mobile phase-B were phosphate buffer and acetonitrile respectively. The column oven temperature was set at 35°C and photodiode array detector was set at 225 nm. Nine process related impurities (Imp-1 to Imp-9) have been detected in test sample of Apixaban by using newly developed RP-HPLC method. Forced degradation study was carried out under acidic, alkaline, oxidative, photolytic and thermal conditions to demonstrate the stability-indicating nature of the developed RP-HPLC method. The developed method was validated as per ICH guideline and found to be specific, precise, sensitive and robust.展开更多
A new, specific, rapid and stability indicating reversed phase liquid chro-matographic (RP-LC) method for the determination of process related and degradation related impurities of Apremilast has been developed and va...A new, specific, rapid and stability indicating reversed phase liquid chro-matographic (RP-LC) method for the determination of process related and degradation related impurities of Apremilast has been developed and validated. The degradation study performed in acid, base, oxidative, photolytic, and thermal stressed conditions. Eight process related impurities (Imp-1 to Imp-8) in test sample of Apremilast have been detected by developed RP-LC method. The good chromatographic resolution between the peaks of process related impurities, degradation impurities and Apremilast has been achieved on a Synergi Max-RP 80 A (150 × 4.6 mm ID), 4 μ column. The process and degradation related impurities were characterized by mass spectrometry, 1H NMR and FT-IR spectral data. The method was validated as per ICH guideline and found to be specific, rapid, and stability indicating. The proposed RP-PLC method was successfully applied to the analysis of drug substance samples of Apremilast.展开更多
For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the proc...For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process.展开更多
This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of t...This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of two dyes(TR+CG-H3G).The Cockle Shell(CS)was used as a natural bio-adsorbent.The characterizations of CS were investigated by Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and Brunauer–Emmett–Teller(BET).The adsorption potential of Cockle Shells was tested in two cases(single and binary system)and determined by:contact time(0–60 min),bio-adsorption dose(3–15 g/L),initial concentration(10–300 mg/L),temperature(22–61°C)and pH solution(2–12).The study of bio-adsorption(equilibrium and kinetics)was conducted at 22°C.The kinetic studies demon-strated that a pseudo-second-order adsorption mechanism had a good correlation coefficient(R2≥0.999).The Langmuir isotherm modeling provided a well-defined description of TR and CG-H3G bio-adsorption on cockle shells,exhibiting maximum capacities of 29.41 and 3.69 mg/g respectively at 22°C.The thermodynamic study shows that the reaction between the TR,CG-H3G dyes molecules and the bio-adsorbent is exothermic,spontaneous in the range of 22–31°C with the aleatory character decrease at the solid-liquid interface.The study of selectivity in single and binary systems has been performed under optimal operating conditions using the industrial textile rejection pH(pH=6.04).CG-H3G dye is found to have a higher selectivity than TR in single(0–60 min)and binary systems with a range of 6–45 min,as shown by the selectivity measurement.It was discovered that CS has the capability to remove both CG-H3G and TR dyes in both simple and binary systems,making it a superior bio-adsorbent.展开更多
The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production ...The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min<sup>-1</sup>, 5358.1461 J·mol<sup>-1</sup>, 1383.03691 min<sup>-1</sup>, 51577.6100 J·mol<sup>-1</sup> respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. Organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.展开更多
This paper compares three methods for natural gas dehydration that are widely applied in industry：（1） absorption by triethylene glycol, （2） adsorption on solid desiccants and （3） condensation. A comparison is m...This paper compares three methods for natural gas dehydration that are widely applied in industry：（1） absorption by triethylene glycol, （2） adsorption on solid desiccants and （3） condensation. A comparison is made according to their energy demand and suitability for use. The energy calculations are performed on a model where 105 Nm3/h water saturated natural gas is processed at 30 °C. The pressure of the gas varies from 7 to 20 MPa. The required outlet concentration of water in natural gas is equivalent to the dew point temperature of -10 °C at gas pressure of 4 MPa.展开更多
Air-bubble generator is the key part of the self-inspiration type swirl flotation machines,whose flow field structure has a great effect on flotation.The multiphase volume of fluid(VOF),standard k-ε turbulent model a...Air-bubble generator is the key part of the self-inspiration type swirl flotation machines,whose flow field structure has a great effect on flotation.The multiphase volume of fluid(VOF),standard k-ε turbulent model and the SIMPLE method were chosen to simulate the present model;the first order upwind difference scheme was utilized to perform a discrete solution for momentum equation.The distributing law of the velocity,pressure,turbulent kinetic energy of every section along the flow direction of air-bubble generator was analyzed.The results indicate that the bubbles are heavily broken up in the middle cross section of throat sect and the entrance of diffuser sect along the flow direction,and the turbulent kinetic energy of diffuser sect is larger than the entrance of throat sect and mixing chamber.展开更多
A type of calcium coke was developed for use in the oxy-thermal process of calcium carbide production.The calcium coke was prepared by the co-pyrolysis of coking coal and calcium carbide slag, which is a solid waste g...A type of calcium coke was developed for use in the oxy-thermal process of calcium carbide production.The calcium coke was prepared by the co-pyrolysis of coking coal and calcium carbide slag, which is a solid waste generated from the chlor-alkali industry.The characteristics of the calcium cokes under different conditions were analyzed experimentally and theoretically.The results show that the thermal strength of calcium coke increased with the increase in the coking coal proportion, and the waterproof property of calcium coke also increased with increased carbonation time.The calcium coke can increase the contact area of calcium and carbon in the calcium carbide production process.Furthermore, the pore structure of the calcium coke can enhance the diffusion of gas inside the furnace, thus improving the efficiency of the oxy-thermal technology.展开更多
Pulp fiber length characterization is addressed in this article. It is .suggested that the proposed separation index H（L） is a viable index to the fiber fractionation performance for evaluating hydrocyclones. Fracti...Pulp fiber length characterization is addressed in this article. It is .suggested that the proposed separation index H（L） is a viable index to the fiber fractionation performance for evaluating hydrocyclones. Fractionation of softwood （coniferous wood） bleached chemithermomechanical pulp （BCTMP） fiber was carried out with a cylindrical hydrocyclone. Pulp fiber length characteristics in different streams were examined using the fiber quality analyzer （FQA）, and the cumulative fiber length fraction, the fiber length fraction density function and the separation index H（L） for different streams were obtained. It is found that H（L） is very useful for characterizing the fiber fractionation performance by indicating the separation capacity of hydrocyclone for individual subgroup of fibers in different streams under different operation conditions. Results of H（L） show that there exists a critical fiber length. A higher proportion of fibers longer than the critical fiber length is in the overflow stream, and a higher proportion of fibers shorter than the critical fiber length in the undertow stream. The data obtained from FQA suggest that the split ratio is the most significant parameter for fiber fractionation performance, which is the best when the split ratio is in the range between 0.14 and 0.2. The effect of feed rate on fiber fractionation performance is weak.展开更多
Bubble motions and bubble-wall interactions in stagnant liquid were experimentally investigated by high-speed CCD and PIV technique with the main feature parameters such as E?tv?s numbers Eo = 0.98–1.10, Morton numbe...Bubble motions and bubble-wall interactions in stagnant liquid were experimentally investigated by high-speed CCD and PIV technique with the main feature parameters such as E?tv?s numbers Eo = 0.98–1.10, Morton number Mo = 3.21 × 10^(-9)and Reynolds numbers Re = 180 ~ 190. The effect of bubble injecting frequency and the distance S between the gas injection nozzle and the wall on the statistical trajectory of bubbles, average velocity distribution of flow field and Reynolds shear stress were studied in detail. It was shown that the combination of bubble injecting frequency and the distance S caused different bubble motion forms and hydrodynamic characteristics.When the normalized initial distance was very little, like S*≈ 1.2(here S*= 2S/d_e, and deis the bubble equivalent diameter), bubbles ascended in a zigzag trajectory with alternant structure of high and low speed flow field around the bubbles, and the distribution of positive and negative Reynolds shear stress looked like a blob. With the increase of distance S*, bubbles' trajectory would tend to be smooth and straight from the zigzag curve. Meanwhile, with the increase of bubble injecting frequency, the camber of bubble trajectory at 20<y<60 mm had a slight increase due to the inhibitory effect from the vertical wall. Under larger spacing, such as S*≈ 3.6, the low-frequency bubbles gradually moved away from the vertical plane wall in a straight trajectory and the high-frequency bubbles gradually moved close to the vertical wall in a similar straight trajectory after an unstable camber motion. Under the circumstances, high-speed fluid was mainly distributed in the region between the wall and the bubbles, while the relative large Reynolds shear stress mainly existed in the region far away from the wall.展开更多
It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are norma...It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are normally used to preclude gas hydrate formation by shifting hydrate stability region to lower temperatures and higher pressures. Sometimes, it is difficult to avoid hydrate formation and hydrates will form anyway. In this situation, kinetic hydrate inhibitors (KHIs) can be used to postpone formation of gas hydrates by retarding hydrate nucleation and growth rate. In this study, two kinetic parameters including natural gas hydrate formation induction time and the rate of gas consumption were experimentally investigated in the presence of monoethylene glycol (MEG), L-tyrosine, and polyvinylpyrrolidone (PVP) at various concentrations in aqueous solutions. Since hydrate formation is a stochastic phenomenon, the repeatability of each kinetic parameter was evaluated several times and the average values for the hydrate formation induction times and the rates of gas consumption are reported. The results indicate that from the view point of hydrate formation induction time, 2 wt% PVP and 20 wt% MEG aqueous solutions have the highest values and are the best choices. It is also interpreted from the results that from the view point of the rate of gas consumption, 20 wt% MEG aqueous solution yields the lowest value and is the best choice. Finally, it is concluded that the combination of PVP and MEG in an aqueous solution has a simultaneous synergistic impact on natural gas hydrate formation induction time and the rate of gas consumption. Furthermore, a semi-empirical model based on chemical kinetic theory is applied to evaluate the hydrate formation induction time data. A good agreement between the experimental and calculated hydrate formation induction time data is observed.展开更多
In this study,natural mackinawite (Fe S),a chalcophilic mineral,was utilized to prepare iron/copper bimetallic oxides (Cu^(O)@Fe_(x)O_(y)) by displacement plating and calcination process.Various characterization metho...In this study,natural mackinawite (Fe S),a chalcophilic mineral,was utilized to prepare iron/copper bimetallic oxides (Cu^(O)@Fe_(x)O_(y)) by displacement plating and calcination process.Various characterization methods prove that Cu;is successfully coated on the surface of Fe S,which were further oxidized to Cu^(O),Fe_(3)O_(4)and/or Fe_(2)O_(3)during calcination process,respectively.Cu^(O)@Fe_(x)O_(y)performed highly efficient capacity to activate PMS for the degradation of various emerging pollutants including sulfamethoxazole(SMX),carbamazepine (CBZ),bisphenol A (BPA),2,4-dichlorophenol (2,4-DCP) and diclofenac (DCF) in aqueous solution.Complete removal of the above pollutants was observed after 8 min of Cu^(O)@Fe_(x)O_(y)/PMS treatment.Taking SMX as an example,the key parameters including Cu^(O)@Fe_(x)O_(y)dosage,PMS dosage and initial p H were optimized.The results show that the catalytic system can be worked in a wide p H range (3.0-9.0).The quenching experiments and electron spin resonance (ESR) test demonstrated that the main reactive oxygen species in Cu^(O)@Fe_(x)O_(y)/PMS system were hydroxyl radicals (^(·)OH) and sulfate radicals(SO_(4)^(·ˉ)),and SO_(4)^(·ˉ)was the primary reactive species.Besides,the influence of coexisting anions (i.e.,Cl^(ˉ),NO_(3)^(ˉ),HCO_(3)^(ˉ)and H_(2)PO_(4)^(ˉ)) for the degradation of SMX was explored.Cu^(O)@Fe_(x)O_(y)/PMS system can maintain good catalytic activity and reusability in different water bodies and long-term running.This work provided a green strategy to fabricate the efficient catalyst in PMS-based advanced oxidation processes.展开更多
Pulp fiber length characterization is addressed in this article. It is suggested that the proposed separation index H(L) is a viable index to the fiber fractionation performance for evaluating hydrocyclones. Fractiona...Pulp fiber length characterization is addressed in this article. It is suggested that the proposed separation index H(L) is a viable index to the fiber fractionation performance for evaluating hydrocyclones. Fractionation of softwood (coniferous wood) bleached chemithermomechanical pulp (BCTMP) fiber was carried out with a cylin- drical hydrocyclone. Pulp fiber length characteristics in different streams were examined using the fiber quality analyzer (FQA), and the cumulative fiber length fraction, the fiber length fraction density function and the separa- tion index H(L) for different streams were obtained. It is found that H(L) is very useful for characterizing the fiber fractionation performance by indicating the separation capacity of hydrocyclone for individual subgroup of fibers in different streams under different operation conditions. Results of H(L) show that there exists a critical fiber length. A higher proportion of fibers longer than the critical fiber length is in the overflow stream, and a higher proportion of fibers shorter than the critical fiber length in the underflow stream. The data obtained from FQA suggest that the split ratio is the most significant parameter for fiber fractionation performance, which is the best when the split ratio is in the range between 0.14 and 0.2. The effect of feed rate on fiber fractionation performance is weak.展开更多
Jadomycin is an antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as ...Jadomycin is an antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as a novel antibiotic and cancer treatment drug. Streptomyces venezuelae are aerobic bacteria that produce jadomycin and the size of bacterial population can significantly affect the yield of jadomycin. Therefore, the bacterial population must be accurately measured in order to standardize the reproducibility of jadomycin production process. In this study, a dehydrogenase activity measurement test, using triphenyl tetrazolium chloride (TTC), was used to measure the dehydrogenase activity of Streptomyces venezuelae during growth in maltose-yeast extract-malt extract (MYM) broth. The aims were to evaluate the effectiveness of the test for measuring microbial growth and to study the effects of the test conditions (incubation time, incubation temperature and medium pH) on triphenyl formazan (TF) yield. The results showed that the TF yield was highly correlated to the optical density. The highest TF yield was observed at a pH of 6 at all incubation times and temperature. Lower TF yields were obtained at higher temperature (40 and 50oC) compared to those obtained at lower temperatures (22 and 30oC). The difference between the yields obtained at 22oC and 30oC were not significant. The differences between incubation time were also not significant. The recommended test conditions are an incubation time of 1 hour at a temperature of 30oC and a pH of 6 followed by three extractions using methanol.展开更多
Fish mortality assessments for turbine passages are currently performed by live-animal testing with up to a hundred thousand fish per year in Germany.A propelled sensor device could act as a fish surrogate.In this con...Fish mortality assessments for turbine passages are currently performed by live-animal testing with up to a hundred thousand fish per year in Germany.A propelled sensor device could act as a fish surrogate.In this context,the study presented here investigates the state of the art via a thorough literature review on propulsion systems for aquatic robots.An evaluation of propulsion performance,weight,size and complexity of the motion achievable allows for the selection of an optimal concept for such a fish mimicking device carrying the sensors.In the second step,the design of a bioinspired soft robotic fish driven by an unconventional drive system is described.It is based on piezoceramic actuators,which allow for motion with five degrees of freedom(DOF)and the creation of complex bio-mimicking body motions.A kinematic model for the motion’s characteristics is developed,to achieve accurate position feedback with the use of strain gauges.Optical measurements validate the complex deformation of the body and deliver the basis for the calibration of the kinematic model.Finally,it can be shown,that the calibrated model presented allows the tracking of the deformation of the entire body with an accuracy of 0.1 mm.展开更多
Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is inv...Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is investigated and compared to a new generation of shape memory alloys, i.e., 60NiTi. Only limited amount of work has been done to investigate the dependency of superelasticity on loading rate of TiNi under localized compressive loads, but much work is directed towards understanding the effect of strain rate on tensile properties. Understanding the superelastic behavior helps to employ superelastic alloys in applications where high impact loading is expected as in bearings and gears. In the present study, it is found that dent resistance of Ti-Ni alloy is not significantly affected by loading rate (within the employed loading conditions). It has also been found that new-generation 60NiTi alloy exhibits superior wear and dent resistance, as well as higher hardness compared to equiatomic TiNi.展开更多
Experience from experimental studies shows that the efficiency of a column packing depends considerably on liquid flow management at the top of the column. Therefore, attention must be drawn to the need for a proper l...Experience from experimental studies shows that the efficiency of a column packing depends considerably on liquid flow management at the top of the column. Therefore, attention must be drawn to the need for a proper liquid distribution design in order to obtain good operation of the packed bed.The choice of the liquid distribution system depends on the geometry of the selected packings and on the operating conditions. One of the main parameters which determines the operation of the distribution and its influence on bed efficiency is the number of liquid feeders. Extensive systematic investigations were carried out under absorption, desorption and rectification conditions in beds of different dumped and regular packings, applying distributors with varying numbers of liquid outlets.The evaluations and modelling of the experimental results led to the determination of the proper number of feeder points, which mainly depends on the packing geometry represented by its open area and void fraction. The main results are shown in the form of diagrams and equations.展开更多
基金financially aided by Fundamental Research Grant Scheme (No. 5524376) from the Ministry of Higher Education of Malaysia and Knowledge Transfer Program Grant (KTP-6228118) from Ministry of Science, Technology and Innovation of Malaysia
文摘Co-composting of poultry manure and rubber wood sawdust was performed with the ratio of 2：1（V/V） for a period of 60 days. An investigation was carried out to study the extracellular enzymatic activities and structural degradation utilizing Fourier transform infrared spectroscopy（FT-IR）, thermogravimetry and differential thermal analysis（TG/DTA）and scanning electron microscopy（SEM）. The microbial succession was also determined by using denaturing gel gradient electrophoresis（DGGE）. The compost was able to reach its highest temperature of 71°C at day 3 and stabilized between 30 and 40°C for 8 weeks.CMCase, FPase and β-glucosidase acted synergistically in order to degrade the cellulosic substrate. The xylanase activities increased gradually during the composting and reached the peak value of 11.637 U/g on day 35, followed by a sharp decline. Both Li P and Mn P activities reached their peak values on day 35 with 0.431 and 0.132 U/g respectively. The FT-IR spectra revealed an increase in aromaticity and a decrease in aliphatic compounds such as carbohydrates as decomposition proceeded. TGA/DTG data exhibited significant changes in weight loss in compost samples, indicating degradation of organic matter. SEM micrographs showed higher amounts of parenchyma exposed on the surface of rubber wood sawdust at day 60, showing significant degradation. DGGE and 16 S r DNA analyses showed that Burkholderia sp., Pandoraea sp., and Pseudomonas sp. were present throughout the composting process. Ornithinibacillus sp. and Castellaniella ginsengisoli were only found in the initial stage of the composting, while different strains of Burkholderia sp. also occurred in the later stage of composting.
文摘Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid （IL） 1-butyl-3-methyl-imi-dazolium hydrogen sulfate （[bmim]HSO4） at ambient pressure in the presence of hydrogen peroxide （H2O2） and potassium peroxymonosulfate （oxone） as the oxidants. Parameters affecting leaching efficiency, such as dissolution time, IL concentration, and oxidizing agent addition, were investigated. The results show that [bmim]HSO4 is an efficient IL for the brass ash leaching, providing the dissolution efficiencies of 99%for Zn and 24.82%for Cu at a concentration of 50vol%[bmim]HSO4 in the aqueous solution without any oxidant. However, more than 99%of zinc and 82%of copper are leached by the addition of 50vol%H2O2 to the [bmim]HSO4 solution. Nevertheless, the oxone does not show the promising oxidant behavior in leaching using [bmim]HSO4.
文摘Collagenase was isolated from fish waste (a mixture of haddock, herring, ground fish and flounder) using a Tris-buffer system. The proteins in the crude extract were precipitated using ammonium sulfate (40% - 80%) and purified with gel-filtration chromatography using Sephadex G-100. The results showed that the collagenase enzyme was produced as a latent enzyme and was activated with bovine trypsin and potassium thiocyanate (KSCN). The enzyme activity was affected by pH and temperature. Optimal enzyme activities were found at 35?C and a pH of 7.5 when insoluble collagene type I was used as substrate and the liberated amino acids were measured in relation to L-leucine in the presence of ninhydrin. The enzyme activity was completely inhibited by the action of ethylenediaminetetraacetic acid (EDTA) suggesting that the collagenase enzyme isolated from the fish waste is a metalloproteinase enzyme requiring metal ions for enzyme activity. Dialysis against KSCN decreased the enzyme total activity and increased its specific activity. Sodium dodecyl sulphate polyacryla-mide gel electrophoresis (SDS-PAGE) indicated that the purified procollagenase enzyme have only one band at molecular weight of 50 kilodaltons (kDa). When the enzyme was cleaved with trypsin, it was found to consist of two subunits: a large unit with a molecular weight of 50 kDa and a small unit with a molecular weight of 10 kDa.
文摘A rapid, specific, sensitive, and precise reverse-phase HPLC method for the quantitative determination of process related and degradation impurities of Apixaban, an anticoagulant drug is described. The developed RP-HPLC method was successfully applied to the analysis of both Apixaban drug substance and drug product. The chromatographic separation was achieved on a Sigma-Aldrich’s Ascentis Express®C18 (4.6 mm × 100 mm, 2.7 μ) HPLC column with a runtime of 40 min. Mobile phase-A and mobile phase-B were phosphate buffer and acetonitrile respectively. The column oven temperature was set at 35°C and photodiode array detector was set at 225 nm. Nine process related impurities (Imp-1 to Imp-9) have been detected in test sample of Apixaban by using newly developed RP-HPLC method. Forced degradation study was carried out under acidic, alkaline, oxidative, photolytic and thermal conditions to demonstrate the stability-indicating nature of the developed RP-HPLC method. The developed method was validated as per ICH guideline and found to be specific, precise, sensitive and robust.
文摘A new, specific, rapid and stability indicating reversed phase liquid chro-matographic (RP-LC) method for the determination of process related and degradation related impurities of Apremilast has been developed and validated. The degradation study performed in acid, base, oxidative, photolytic, and thermal stressed conditions. Eight process related impurities (Imp-1 to Imp-8) in test sample of Apremilast have been detected by developed RP-LC method. The good chromatographic resolution between the peaks of process related impurities, degradation impurities and Apremilast has been achieved on a Synergi Max-RP 80 A (150 × 4.6 mm ID), 4 μ column. The process and degradation related impurities were characterized by mass spectrometry, 1H NMR and FT-IR spectral data. The method was validated as per ICH guideline and found to be specific, rapid, and stability indicating. The proposed RP-PLC method was successfully applied to the analysis of drug substance samples of Apremilast.
文摘For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process.
基金supported by the University Salah Boubnider-Constantine 3 (Algeria).
文摘This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of two dyes(TR+CG-H3G).The Cockle Shell(CS)was used as a natural bio-adsorbent.The characterizations of CS were investigated by Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and Brunauer–Emmett–Teller(BET).The adsorption potential of Cockle Shells was tested in two cases(single and binary system)and determined by:contact time(0–60 min),bio-adsorption dose(3–15 g/L),initial concentration(10–300 mg/L),temperature(22–61°C)and pH solution(2–12).The study of bio-adsorption(equilibrium and kinetics)was conducted at 22°C.The kinetic studies demon-strated that a pseudo-second-order adsorption mechanism had a good correlation coefficient(R2≥0.999).The Langmuir isotherm modeling provided a well-defined description of TR and CG-H3G bio-adsorption on cockle shells,exhibiting maximum capacities of 29.41 and 3.69 mg/g respectively at 22°C.The thermodynamic study shows that the reaction between the TR,CG-H3G dyes molecules and the bio-adsorbent is exothermic,spontaneous in the range of 22–31°C with the aleatory character decrease at the solid-liquid interface.The study of selectivity in single and binary systems has been performed under optimal operating conditions using the industrial textile rejection pH(pH=6.04).CG-H3G dye is found to have a higher selectivity than TR in single(0–60 min)and binary systems with a range of 6–45 min,as shown by the selectivity measurement.It was discovered that CS has the capability to remove both CG-H3G and TR dyes in both simple and binary systems,making it a superior bio-adsorbent.
文摘The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min<sup>-1</sup>, 5358.1461 J·mol<sup>-1</sup>, 1383.03691 min<sup>-1</sup>, 51577.6100 J·mol<sup>-1</sup> respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. Organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.
基金supported by the Inovation and Optimalization of Technologies for Natural Gas Dehydration(No.FR-TI1/173)
文摘This paper compares three methods for natural gas dehydration that are widely applied in industry：（1） absorption by triethylene glycol, （2） adsorption on solid desiccants and （3） condensation. A comparison is made according to their energy demand and suitability for use. The energy calculations are performed on a model where 105 Nm3/h water saturated natural gas is processed at 30 °C. The pressure of the gas varies from 7 to 20 MPa. The required outlet concentration of water in natural gas is equivalent to the dew point temperature of -10 °C at gas pressure of 4 MPa.
基金Project supported by the Scientific Research Foundation of Hebei University of Technology of China
文摘Air-bubble generator is the key part of the self-inspiration type swirl flotation machines,whose flow field structure has a great effect on flotation.The multiphase volume of fluid(VOF),standard k-ε turbulent model and the SIMPLE method were chosen to simulate the present model;the first order upwind difference scheme was utilized to perform a discrete solution for momentum equation.The distributing law of the velocity,pressure,turbulent kinetic energy of every section along the flow direction of air-bubble generator was analyzed.The results indicate that the bubbles are heavily broken up in the middle cross section of throat sect and the entrance of diffuser sect along the flow direction,and the turbulent kinetic energy of diffuser sect is larger than the entrance of throat sect and mixing chamber.
基金financially supported by the Natural Science Foundation of China (Nos.U1610101 and 21776288)the Green Process Manufacturing Innovation Research Institute, Chinese Academy of Sciences (No.IAGM-2019-A09)the funding support from Vinnova (Dn: 2018-05293)。
文摘A type of calcium coke was developed for use in the oxy-thermal process of calcium carbide production.The calcium coke was prepared by the co-pyrolysis of coking coal and calcium carbide slag, which is a solid waste generated from the chlor-alkali industry.The characteristics of the calcium cokes under different conditions were analyzed experimentally and theoretically.The results show that the thermal strength of calcium coke increased with the increase in the coking coal proportion, and the waterproof property of calcium coke also increased with increased carbonation time.The calcium coke can increase the contact area of calcium and carbon in the calcium carbide production process.Furthermore, the pore structure of the calcium coke can enhance the diffusion of gas inside the furnace, thus improving the efficiency of the oxy-thermal technology.
文摘Pulp fiber length characterization is addressed in this article. It is .suggested that the proposed separation index H（L） is a viable index to the fiber fractionation performance for evaluating hydrocyclones. Fractionation of softwood （coniferous wood） bleached chemithermomechanical pulp （BCTMP） fiber was carried out with a cylindrical hydrocyclone. Pulp fiber length characteristics in different streams were examined using the fiber quality analyzer （FQA）, and the cumulative fiber length fraction, the fiber length fraction density function and the separation index H（L） for different streams were obtained. It is found that H（L） is very useful for characterizing the fiber fractionation performance by indicating the separation capacity of hydrocyclone for individual subgroup of fibers in different streams under different operation conditions. Results of H（L） show that there exists a critical fiber length. A higher proportion of fibers longer than the critical fiber length is in the overflow stream, and a higher proportion of fibers shorter than the critical fiber length in the undertow stream. The data obtained from FQA suggest that the split ratio is the most significant parameter for fiber fractionation performance, which is the best when the split ratio is in the range between 0.14 and 0.2. The effect of feed rate on fiber fractionation performance is weak.
基金Supported by the National Natural Science Foundation of China(11572357,11602077)
文摘Bubble motions and bubble-wall interactions in stagnant liquid were experimentally investigated by high-speed CCD and PIV technique with the main feature parameters such as E?tv?s numbers Eo = 0.98–1.10, Morton number Mo = 3.21 × 10^(-9)and Reynolds numbers Re = 180 ~ 190. The effect of bubble injecting frequency and the distance S between the gas injection nozzle and the wall on the statistical trajectory of bubbles, average velocity distribution of flow field and Reynolds shear stress were studied in detail. It was shown that the combination of bubble injecting frequency and the distance S caused different bubble motion forms and hydrodynamic characteristics.When the normalized initial distance was very little, like S*≈ 1.2(here S*= 2S/d_e, and deis the bubble equivalent diameter), bubbles ascended in a zigzag trajectory with alternant structure of high and low speed flow field around the bubbles, and the distribution of positive and negative Reynolds shear stress looked like a blob. With the increase of distance S*, bubbles' trajectory would tend to be smooth and straight from the zigzag curve. Meanwhile, with the increase of bubble injecting frequency, the camber of bubble trajectory at 20<y<60 mm had a slight increase due to the inhibitory effect from the vertical wall. Under larger spacing, such as S*≈ 3.6, the low-frequency bubbles gradually moved away from the vertical plane wall in a straight trajectory and the high-frequency bubbles gradually moved close to the vertical wall in a similar straight trajectory after an unstable camber motion. Under the circumstances, high-speed fluid was mainly distributed in the region between the wall and the bubbles, while the relative large Reynolds shear stress mainly existed in the region far away from the wall.
文摘It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are normally used to preclude gas hydrate formation by shifting hydrate stability region to lower temperatures and higher pressures. Sometimes, it is difficult to avoid hydrate formation and hydrates will form anyway. In this situation, kinetic hydrate inhibitors (KHIs) can be used to postpone formation of gas hydrates by retarding hydrate nucleation and growth rate. In this study, two kinetic parameters including natural gas hydrate formation induction time and the rate of gas consumption were experimentally investigated in the presence of monoethylene glycol (MEG), L-tyrosine, and polyvinylpyrrolidone (PVP) at various concentrations in aqueous solutions. Since hydrate formation is a stochastic phenomenon, the repeatability of each kinetic parameter was evaluated several times and the average values for the hydrate formation induction times and the rates of gas consumption are reported. The results indicate that from the view point of hydrate formation induction time, 2 wt% PVP and 20 wt% MEG aqueous solutions have the highest values and are the best choices. It is also interpreted from the results that from the view point of the rate of gas consumption, 20 wt% MEG aqueous solution yields the lowest value and is the best choice. Finally, it is concluded that the combination of PVP and MEG in an aqueous solution has a simultaneous synergistic impact on natural gas hydrate formation induction time and the rate of gas consumption. Furthermore, a semi-empirical model based on chemical kinetic theory is applied to evaluate the hydrate formation induction time data. A good agreement between the experimental and calculated hydrate formation induction time data is observed.
基金financial support from National Natural Science Foundation of China (No.51878423)China Postdoctoral Science Foundation (No.2019T120843)Sichuan Science and Technology Program (No.2019YJ0091)。
文摘In this study,natural mackinawite (Fe S),a chalcophilic mineral,was utilized to prepare iron/copper bimetallic oxides (Cu^(O)@Fe_(x)O_(y)) by displacement plating and calcination process.Various characterization methods prove that Cu;is successfully coated on the surface of Fe S,which were further oxidized to Cu^(O),Fe_(3)O_(4)and/or Fe_(2)O_(3)during calcination process,respectively.Cu^(O)@Fe_(x)O_(y)performed highly efficient capacity to activate PMS for the degradation of various emerging pollutants including sulfamethoxazole(SMX),carbamazepine (CBZ),bisphenol A (BPA),2,4-dichlorophenol (2,4-DCP) and diclofenac (DCF) in aqueous solution.Complete removal of the above pollutants was observed after 8 min of Cu^(O)@Fe_(x)O_(y)/PMS treatment.Taking SMX as an example,the key parameters including Cu^(O)@Fe_(x)O_(y)dosage,PMS dosage and initial p H were optimized.The results show that the catalytic system can be worked in a wide p H range (3.0-9.0).The quenching experiments and electron spin resonance (ESR) test demonstrated that the main reactive oxygen species in Cu^(O)@Fe_(x)O_(y)/PMS system were hydroxyl radicals (^(·)OH) and sulfate radicals(SO_(4)^(·ˉ)),and SO_(4)^(·ˉ)was the primary reactive species.Besides,the influence of coexisting anions (i.e.,Cl^(ˉ),NO_(3)^(ˉ),HCO_(3)^(ˉ)and H_(2)PO_(4)^(ˉ)) for the degradation of SMX was explored.Cu^(O)@Fe_(x)O_(y)/PMS system can maintain good catalytic activity and reusability in different water bodies and long-term running.This work provided a green strategy to fabricate the efficient catalyst in PMS-based advanced oxidation processes.
基金Supported by the Natural Science and Engineering Research Council of Canada.
文摘Pulp fiber length characterization is addressed in this article. It is suggested that the proposed separation index H(L) is a viable index to the fiber fractionation performance for evaluating hydrocyclones. Fractionation of softwood (coniferous wood) bleached chemithermomechanical pulp (BCTMP) fiber was carried out with a cylin- drical hydrocyclone. Pulp fiber length characteristics in different streams were examined using the fiber quality analyzer (FQA), and the cumulative fiber length fraction, the fiber length fraction density function and the separa- tion index H(L) for different streams were obtained. It is found that H(L) is very useful for characterizing the fiber fractionation performance by indicating the separation capacity of hydrocyclone for individual subgroup of fibers in different streams under different operation conditions. Results of H(L) show that there exists a critical fiber length. A higher proportion of fibers longer than the critical fiber length is in the overflow stream, and a higher proportion of fibers shorter than the critical fiber length in the underflow stream. The data obtained from FQA suggest that the split ratio is the most significant parameter for fiber fractionation performance, which is the best when the split ratio is in the range between 0.14 and 0.2. The effect of feed rate on fiber fractionation performance is weak.
文摘Jadomycin is an antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as a novel antibiotic and cancer treatment drug. Streptomyces venezuelae are aerobic bacteria that produce jadomycin and the size of bacterial population can significantly affect the yield of jadomycin. Therefore, the bacterial population must be accurately measured in order to standardize the reproducibility of jadomycin production process. In this study, a dehydrogenase activity measurement test, using triphenyl tetrazolium chloride (TTC), was used to measure the dehydrogenase activity of Streptomyces venezuelae during growth in maltose-yeast extract-malt extract (MYM) broth. The aims were to evaluate the effectiveness of the test for measuring microbial growth and to study the effects of the test conditions (incubation time, incubation temperature and medium pH) on triphenyl formazan (TF) yield. The results showed that the TF yield was highly correlated to the optical density. The highest TF yield was observed at a pH of 6 at all incubation times and temperature. Lower TF yields were obtained at higher temperature (40 and 50oC) compared to those obtained at lower temperatures (22 and 30oC). The difference between the yields obtained at 22oC and 30oC were not significant. The differences between incubation time were also not significant. The recommended test conditions are an incubation time of 1 hour at a temperature of 30oC and a pH of 6 followed by three extractions using methanol.
基金Open Access funding enabled and organized by Projekt DEALpart of the RETERO project(https://retero.org).S.A.was funded by the German Ministry of Education and Research(BMBF)with grant number 031L0152A.
文摘Fish mortality assessments for turbine passages are currently performed by live-animal testing with up to a hundred thousand fish per year in Germany.A propelled sensor device could act as a fish surrogate.In this context,the study presented here investigates the state of the art via a thorough literature review on propulsion systems for aquatic robots.An evaluation of propulsion performance,weight,size and complexity of the motion achievable allows for the selection of an optimal concept for such a fish mimicking device carrying the sensors.In the second step,the design of a bioinspired soft robotic fish driven by an unconventional drive system is described.It is based on piezoceramic actuators,which allow for motion with five degrees of freedom(DOF)and the creation of complex bio-mimicking body motions.A kinematic model for the motion’s characteristics is developed,to achieve accurate position feedback with the use of strain gauges.Optical measurements validate the complex deformation of the body and deliver the basis for the calibration of the kinematic model.Finally,it can be shown,that the calibrated model presented allows the tracking of the deformation of the entire body with an accuracy of 0.1 mm.
文摘Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is investigated and compared to a new generation of shape memory alloys, i.e., 60NiTi. Only limited amount of work has been done to investigate the dependency of superelasticity on loading rate of TiNi under localized compressive loads, but much work is directed towards understanding the effect of strain rate on tensile properties. Understanding the superelastic behavior helps to employ superelastic alloys in applications where high impact loading is expected as in bearings and gears. In the present study, it is found that dent resistance of Ti-Ni alloy is not significantly affected by loading rate (within the employed loading conditions). It has also been found that new-generation 60NiTi alloy exhibits superior wear and dent resistance, as well as higher hardness compared to equiatomic TiNi.
文摘Experience from experimental studies shows that the efficiency of a column packing depends considerably on liquid flow management at the top of the column. Therefore, attention must be drawn to the need for a proper liquid distribution design in order to obtain good operation of the packed bed.The choice of the liquid distribution system depends on the geometry of the selected packings and on the operating conditions. One of the main parameters which determines the operation of the distribution and its influence on bed efficiency is the number of liquid feeders. Extensive systematic investigations were carried out under absorption, desorption and rectification conditions in beds of different dumped and regular packings, applying distributors with varying numbers of liquid outlets.The evaluations and modelling of the experimental results led to the determination of the proper number of feeder points, which mainly depends on the packing geometry represented by its open area and void fraction. The main results are shown in the form of diagrams and equations.
