Shock Raman spectra and structural transformation of powdered TKX-50 by the plate impact experiments combined with real-time Raman detection

As an energetic material of great interest,the work capacity of dihydroxylammonium 5,5’-bistetrazole-1,1’-diolate(TKX-50)has been questioned recently.Although some research groups have explored the reasons for the low working ability of TKX-50,the plane impact experiment on powdered TKX-50 is obviously closer to the practical application,and the conclusions based on this are more guiding.Hence,we performed shock Hugoniot measurements of powdered TKX-50 between 5.65 and 16.29 GPa.The plane impact experiments of powdered TKX-50 were carried out and the shocked Raman spectra were collected.By Raman spectroscopy analysis,a new peak of powdered TKX-50 was found between19.47 GPa and 24.96 GPa,which may be caused by decomposition/phase transition and was related with the low work capacity.

Study of the reaction mechanism for preparing powdered activated coke with SO_(2)adsorption capability via one-step rapid activation method under flue gas atmosphere

In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.

Effect of powdered activated carbon on Chinese traditional medicine wastewater treatment in submerged membrane bioreactor with electronic control backwashing

Chinese traditional medicine wastewater, rich in macromolecule and easy to foam in aerobic biodegradation such as Glycosides, was treated by two identical bench-scale aerobic submerged membrane bioreactors （SMBRs） operated in parallel under the same feed, equipped with the same electronic control backwashing device. One was used as the control SMBR （CSMBR） while the other was dosed with powdered activated carbon （PAC） （PAC-amended SMBR, PSMBR）. The backwashing interval was 5 min. One suction period was about 90 min by adjusting preestablished backwashing vacuum and pump frequency. The average flux of CSMBR during a steady periodic state of 24 d （576 h） was 5.87 L/h with average hydraulic residence time （HRT） of 5.97 h and that of PSMBR during a steady periodic state of 30 d （720 h） was 5.85 L/h with average HRT of 5.99 h. The average total chemical oxygen demand （COD） removal efficiency of CSMBR was 89.29% with average organic loading rate （OLR） at 4.16 kg COD/（m^3.d） while that of PSMBR was 89.79% with average OLR at 5.50 kg COD/（m^3.d）. COD concentration in the effluent of both SMBRs achieved the second level of the general wastewater effluent standard GB8978-1996 for the raw medicine material industry （300 mg/L）. Hence, SMBR with electronic control backwashing was a viable process for medium-strength Chinese traditional medicine wastewater treatment. Moreover, the increasing rates of preestablished backwashing vacuum, pump frequency, and vacuum and flux loss caused by mixed liquor in PSMBR all lagged compared to those in CSMBR; thus the actual operating time of the PSMBR system without membrane cleaning was extended by up to 1.25 times in contrast with the CSMBR system, and the average total COD removal efficiency of PSMBR was enhanced with higher average OLR.

DYNAMIC RHEOLOGICAL BEHAVIOR OF POLYPROPYLENE FILLED WITH ULTRA-FINE POWDERED RUBBER PARTICLES

Dynamic rheological characteristics of polypropylene (PP) filled with ultra-fine full-vulcanized powdered rubber (UFPR) composed of styrene-butadiene copolymer were studied through dynamic rheological measurements on an Advanced Rheometric Expansion System (ARES). A specific viscoelastic phenomenon, i.e. 'the second plateau', appeared at low frequencies, and exhibits a certain dependence on the amount of rubber particles and the dispersion state in the matrix. This phenomenon is attributed to the formation of aggregation structure of rubber particles. The analyses of Cole-Cole diagrams of the dynamic viscoelastic functions suggest that the heterogeneity of the composites is enhanced on increasing both particle content and temperature.

The Survey of Cronobacter spp.(formerly Enterbacter sakazakii) in Infant and Follow-up Powdered Formula in China in 2012

Objective To determine Cronobacter spp. contamination in infant and follow-up powdered formula in China. Methods All of 2282 samples were collected from the retail markets in China from January 2012 to December 2012, and analyzed for Cronobacter spp. by the Chinese National Food Safety Standard. Characterization of the isolates was analyzed by pulsed-field gel electrophoresis（PFGE） with XbaI and Spe I restriction enzymes. Results Cronobacter spp. strains were isolated from 25 samples, and the positive rates in infant powdered formulas and follow-up powdered formulas were 0.90%（10/1011） and 1.18%（15/1271）, respectively. Analysis of variable data regarding different purchasing store formats, seasonality, and production locations as well as comparison of infant versus follow-up formulas did not reveal statistically significant factors. During the sampling period, one of six surveillance zones did exhibit a statistically significant trend towards higher positive rate. PFGE characterization of Cronobacter spp. to elucidate genetic diversity revealed only three pairs of Cronobacter spp. out of 25 having the same PFGE patterns. Conclusion The current investigation indicated a lower positive rate of Cronobacter spp. in the powdered formula in China. This evidence suggested contamination originating from multiple different sources during the manufacturing process.

Evaluation of Powdered Activated Carbon Treatment Process in Petrochemical Wastewater Purification

The powdered activated carbon treatment(PACT) process has been widely used in many industrial fields, however,very few PACT processes are built for petrochemical wastewater treatment in China. An industrial PACT unit launched in a petrochemical plant was introduced and evaluated from both the practice and mechanism study. Practically, the PACT process showed excellent capability in pollutants removal, shock resistance, toxicity tolerance, and the COD and ammoniumN in effluent of PACT unit assisted by PAC was equal to 15.5 mg/L and 0.7 mg/L lower than that without PAC addition,respectively. The wet oxidation regeneration unit was quite efficient in supplying regenerated PAC, and, however, the hard calcium sulphate scale and the high pollutant concentration solution needed to be carefully controlled. Moreover, although the carbon balance showed that the adsorption capability of regenerated PAC was negligible, the biological tests proved that the regenerated PAC increased microbe activity up to 17% more than pure activated sludge system, which was almost compatible with the fresh activated carbon.

Detection and Molecular Characterization of <i>Cronobacter sakazakii</i>Isolated from Powdered Infant Formula (PIF) from North Central Region, Nigeria

Cronobacter sakazakii is an emerging ubiquitous and opportunistic pathogen that currently contaminates a wide spectrum of foods including powdered milk and poses a lethal threat to neonates, the elderly and persons with immune deficiencies. They cause life threatening neonatal meningitis, septicemia, and necrotizing enterocolitis. A total of 360 samples of powdered infant formula were collected from postnatal hospital attendees reconstituting the PIF for their children in the North Central region of Nigeria where cases of infant mortality are very high and presenting as enterocolitis and diarrhea. Pre-enriched samples were cultured in chromogenic Cronobacter broth and were then further sub-cultured into a chromogenic Cronobacter sakazakii agar. They were positive, exhibiting yellowish cultures typical of Cronobacter sakazakii. Biochemical tests of the isolates were also carried out and indicated the presence of Cronobacter sakazakii. The isolates were then characterized molecularly using specie specific PCR detection of Cronobacter sakazakii. The targeted genes of interest were ompA gene and CPA gene. The isolates tested showed bands for ompA gene on electrophoresis imager and were confirmed as Cronobacter sakazakii. In Nigeria, majority of infants are still fed with PIF. There is no existing data on the detection of Cronobacter sakazakii previously reported in the North central region of Nigeria hence the need to carry out the present study. The result of the study demonstrated the need for effective prevention and control measures as contamination of PIF with Cronobacter sakazakii constituted potential public health risk to neonates and infants.

Study on Inorganic Flocculant Prepared from Powdered Coal Ashes

The feasibility of preparing flocculant from powdered coal ashes is studied in detail. By means of orthogonal tests, the influence of various factors, such as the activation temperature, the activation time, the ratio of CaO to Al2O3, the hydrochloric acid concentration, the reaction time and the reaction temperature, on preparation is investigated, and the hest operating condition is determined.

Fast adsorption of microcystin-LR by Fe(Ⅲ)-modified powdered activated carbon

Microcystins(MCs) are cyclic hepatotoxic peptides produced by the bloom-forming cyanobacterium Microcystis and present a public health hazard to humans and livestock. The removal of MCs from contaminated water with powdered activated carbon(PAC) has been employed as a simple and economic treatment strategy. In this study, PAC-Fe(Ⅲ) was prepared and utilized for the fast and efficient removal of MCs from water. PAC-Fe(Ⅲ) exhibited superior microcystin-LR(MC-LR) removal capacity and efficiency compared to the unmodified PAC. The MC-LR removal efficiency of PAC-Fe(Ⅲ) increased with decreasing p H within the pH range of 4.3 to 9.6. PAC-Fe(Ⅲ) could be reused for 3 times by methanol elution while the MC-LR removal efficiency was still over 70 percent. The removal efficiency was positively correlated to the ionic strength of water and negatively correlated to alkalinity. Natural organic matter(NOM) such as humic acid(HA) and salicylic acid(SA) generated low interference with MC-LR adsorption by PAC-Fe(Ⅲ). The complexation reaction between Fe^(3+) in PAC-Fe(Ⅲ) and the functional groups of MCLR was suggested as the key mechanism of MC-LR removal by PAC-Fe(Ⅲ). The results suggest that Femodified PAC is a promising material for the treatment of MC-contaminated waters.

Study on Regeneration of Powdered Activated Carbon by Electron Beam

The powdered activated carbon which had adsorbed phenylglycine solution from pharmaceutics factory can be regenerated by mean of irradiation of high-energy electron beams in oxygen, nitrogen and water vapor respectively. The effects of radiation dose and beam current on regeneration of activated carbon in different atmosphere were studied. Differential scanning calorimetry (DSC) and the iodine number of activated carbon were used to monitor the change of carbon adsorption. The results show that the powder activated carbon polluted with phenlglycine could be regenerated effectively by irradiation of high energy electron beams in nitrogen stream. The generation did not need high temperature, and the weight loss of carbon and energy consumption were minimum.

Adsorption Characteristics of the Powdered Activated Carbon on Pesticide in the Water

The adsorption characteristics of the powdered activated carbon on four kinds of pesticides （ dichlorvos, chlorothalonil, lindane and chlorphyrifos） were studied, and the influential factors of adsorption effect were discussed. Results showed that the powdered activated carbon could effectively remove the above four kinds of pesticides. It was rapid adsorption period before 30 min, and removal rate has reached 90%. Adsorption kinetics of the powdered activated carbon on pesticides corresponded with quasi-two-level kinetic equation, and both Freundlich and Langmuir adsorption isotherms could simulate the adsorption process of the activated carbon on pesticide well. Competitive adsorption between small-molecule organics in the water diverting from Yellow River and Desticides on microDore of the activated carbon would occur.

Distribution of Colloidal and Powdered Activated Carbon for the <i>in Situ</i>Treatment of Groundwater

The use of in situ technologies for the treatment of groundwater containing various compounds of concern are widely accepted. These technologies include chemical reduction, chemical oxidation, anaerobic and aerobic bioremediation, and adsorption, among others. One requirement for the successful application of these technologies is the delivery of the remedial reagent(s) to the compounds of concern. A rapidly evolving in situ technology is the injection of adsorptive media such as activated carbon and ion-exchange resin including powdered or colloidal activated carbon. Activated carbon has a long-demonstrated history of effectiveness for the removal of various organic and inorganic compounds in above ground water treatment systems. However, due to constraints related to the particle size and physical properties of the activated carbon, the in situ application of activated carbon has been limited. Recent developments in the manufacturing of activated carbon have created a smaller particle size allowing activated carbon to be applied in situ. To evaluate if powdered and colloidal activated carbon can be effectively distributed in aquifers, the two types of carbon were injected using direct push technology adjacent to each other at four sites with varying geology. Evaluation of distribution was completed by sampling the aquifer prior to and post-injection for total organic carbon. The results of the studies indicated that both forms of activated carbon were effectively delivered to the targeted injection zones with both carbon types being detected at least seven meters away from the point of injection. The colloidal form of the activated carbon showed good distribution throughout the four targeted zones of injection with 93 percent of the samples collected having colloidal activated carbon present within them whereas the powdered activated carbon cells were more susceptible to aquifer heterogeneity with only 67 percent of the samples collected having activated carbon present. Preferential accumulation of activated carbon was observed in high horizontal hydraulic conductivity seams, especially within the powdered activated carbon cells. These results suggested that the powdered form of activated carbon was more suspectable at the four sites to heterogeneity within the aquifer than the colloidal form of activated carbon. Sampling of monitoring well screens installed prior to the injection of the two forms of activated carbon showed preferential accumulation of powdered activated carbon within the sand pack, which could result in sampling bias.

Study of Factors Affecting Medical Incident: 2 Powdered Medication Dispensing

Medical incidents have been collected, analyzed and built up preventive measures by each medical institution for a long time. For powdered medication, there is the problem that it is difficult to tell at a glance the quantity of the active ingredient in the medication that has been dispensed and the quantities that have been mixed together. Therefore, special prevention measures are considered essential. In this study, we examined the work content of pharmacists’ powdered medication dispensing, using an eye-tracking technology of measuring a human eye movement, and studied on factors that affect medical incident. Participants were five pharmacists with 8 to 26 years of working experience (expert), and five pharmacists with less than one year of working experience (newcomer). Gaze measurement experiments were implemented for powdered medication dispensing during regular work activity. The gaze measurement equipment used was Tobii Pro Glasses 2. Based on the results of the eye tracking, newcomer had a longer dispensing time than expert for all powdered medication dispensing. In particular, it was suggested that there is a close relationship to “years of experience” and “weighing and mixing skills.” Experts did unwasted and efficient movements, when preparing the dispensing apparatus, taking medications from the shelves, and scanning the barcode in the powders dispensing checking system. These movements led to shorter working time in experts. In contrast, newcomer had individual differences at the dispensing. Even with the same pharmacist, the work progression differed depending upon the prescription. Therefore, it is thought that the factor of common error was inadequate check and overlooked. The state that it’s messy on the workplace is also considered highly likely to cause dispensing mistakes. At the weighing, expert started weighing after the inspection of the prescription and checking weighed amount. However, certain newcomer dispensed to depend on the powders dispensing checking system only for the weighing process, without the inspection of the prescription or checking weighed amount. Irregular doses for infants and older patients require fine adjustments;therefore, the powders dispensing checking system may not find all dispensing errors. It is important for a pharmacist to, first, be written calculated weight on the prescription and checked by themselves, and next to begin dispensation work. In the future, as well as the powdered medication dispensing, it is necessary to make use of measures for preventing errors in the various dispensing process, such as the medication inspection, sterile products preparation, clinical practice et al.

Part 1: Synthesis and Evaluation of Novel Nano Scale Powdered Polyurethane Acrylate Binders

Some new an aqueous polyurethane acrylate (waterborne binder) based on polyethylene glycol with different M. wt. mixed with polyol were carried out. Seven different polyurethane acrylate co-polymers were prepared aiming at substituting the two hydroxyl groups of polyethylene glycol (6000, 12,000 and 20,000 g/mol) and two primary hydroxyl groups of polyol through their reaction with corresponding calculated amounts of either isophorone diisoyanate or toluene diisocyanate and caped the remaining isocyanate group with either hydroxy ethyl acrylate or hydroxy propyl methacrylate to get on the polyurethane acrylate polymers [PUA]. From DSC measurement the result of Tg of synthesized PUA are in range from -8.78℃ to 36.4℃. So they can classify as soft binders. The infrared spectra, rheological properties, viscosity measurement, the weight average molecular weight, of the synthesize binders were investigated.

STUDY ON THE FUNCTION OF REINFORCED RUBBER OF MODIFIED POWDERED COAL ASH

The powdered coal ash (PCA) was classified, then the ash particle (- 45μm) was modified by a surface active agent and obtained modified powder coal ash (MPCA). The character of the MPC was investigated, when it was used as a new type reinforced filler of rubber.The results show that MPCA can replace or party replace carbon black or silica as reinforced fillers of rubbers.

Dynamic membrane bioreactor performance enhancement by powdered activated carbon addition:Evaluation of sludge morphological,aggregative and microbial properties

The effects of powdered activated carbon(PAC) addition on sludge morphological, aggregative and microbial properties in a dynamic membrane bioreactor(DMBR) were investigated to explore the enhancement mechanism of pollutants removal and filtration performance. Sludge properties were analyzed through various analytical measurements. The results showed that the improved sludge aggregation ability and the evolution of microbial communities affected sludge morphology in PAC-DMBR, as evidenced by the formation of large, regularly shaped and strengthened sludge flocs. The modifications of sludge characteristics promoted the formation process and filtration flux of the dynamic membrane(DM) layer. Additionally, PAC addition did not exert very significant influence on the propagation of eukaryotes(protists and metazoans)and microbial metabolic activity. High-throughput pyrosequencing results indicated that adding PAC improved the bacterial diversity in activated sludge, as PAC addition brought about additional microenvironment in the form of biological PAC(BPAC), which promoted the enrichment of Acinetobacter(13.9%), Comamonas(2.9%), Flavobacterium(0.31%) and Pseudomonas(0.62%), all contributing to sludge flocs formation and several(such as Acinetobacter) capable of biodegrading relatively complex organics. Therefore, PAC addition could favorably modify sludge properties from various aspects and thus enhance the DMBR performance.

Simultaneous removal of ammonia and N-nitrosamine precursors from high ammonia water by zeolite and powdered activated carbon

When adding sufficient chlorine to achieve breakpoint chlorination to source water containing high concentration of ammonia during drinking water treatment, high concentrations of disinfection by-products（DBPs） may form. If N-nitrosamine precursors are present, highly toxic N-nitrosamines, primarily N-nitrosodimethylamine（NDMA）, may also form. Removing their precursors before disinfection should be a more effective way to minimize these DBPs formation. In this study, zeolites and activated carbon were examined for ammonia and N-nitrosamine precursor removal when incorporated into drinking water treatment processes.The test results indicate that Mordenite zeolite can remove ammonia and five of seven N-nitrosamine precursors efficiently by single step adsorption test. The practical applicability was evaluated by simulation of typical drinking water treatment processes using six-gang stirring system. The Mordenite zeolite was applied at the steps of lime softening, alum coagulation, and alum coagulation with powdered activated carbon（PAC） sorption. While the lime softening process resulted in poor zeolite performance, alum coagulation did not impact ammonia and N-nitrosamine precursor removal. During alum coagulation, more than67% ammonia and 70%–100% N-nitrosamine precursors were removed by Mordenite zeolite（except 3-（dimethylaminomethyl）indole（DMAI） and 4-dimethylaminoantipyrine（DMAP））. PAC effectively removed DMAI and DMAP when added during alum coagulation. A combination of the zeolite and PAC selected efficiently removed ammonia and all tested seven N-nitrosamine precursors（dimethylamine（DMA）, ethylmethylamine（EMA）, diethylamine（DEA）, dipropylamine（DPA）, trimethylamine（TMA）, DMAP, and DMAI） during the alum coagulation process.

Ammonia removal from low-strength municipal wastewater by powdered resin combined with simultaneous recovery as struvite

Low-strength municipal wastewater is considered to be a recoverable nutrient resource with economic and environmental benefits.Thus,various technologies for nutrient removal and recovery have been developed.In this paper,powdered ion exchange resin was employed for ammonia removal and recovery from imitated low-strength municipal wastewater.The effects of various working conditions(powdered resin dosage,initial concentration,and pH value)were studied in batch experiments to investigate the feasibility of the approach and to achieve performance optimization.The maximum adsorption capacity determined by the Langmuir model was 44.39 mg/g,which is comparable to traditional ion exchange resin.Further,the effects of co-existing cations(Ca^(2+),Mg^(2+),K^(+))were studied.Based on the above experiments,recovery of ammonia as struvite was successfully achieved by a proposed two-stage crystallization process coupled with a powdered resin ion exchange process.Scanning electron microscopy(SEM)and X-ray diffractometry(XRD)results revealed that struvite crystals were successfully gained in alkaline conditions(pH=10).This research demonstrates that a powdered resin and two-stage crystallization process provide an innovative and promising means for highly efficient and easy recovery from low-strength municipal wastewater.

Removal of bromate ion using powdered activated carbon

Bromate ion （BrO3-） removal from drinking water by powdered activated carbons （PACs） in bath mode was evaluated under various operational conditions. Six kinds of PACs, including wood-based carbon, fruit-based carbon, coal-based carbon, and these three carbons thermally deoxidized in a nitrogen atmosphere, were selected to investigate their capacity on BrO3- removal. With the highest zeta potential value and being richly mesoporous, coal-based carbon had a high and an excellent BrO3- adsorption efficiency. The removal content of BrO3- by per gram of coal-based carbon was 0.45 mg within 5 hr in 100 μg/L bromate solution. The surface characteristics of PACs and bromide formation revealed that both physical and chemical PACs properties simultaneously affected the adsorptionreduction process. Under acidic conditions, PACs possessed high zeta value and adequate basic groups and exhibited neutral or positive charges, promoting BrO3- adsorption-reduction on the carbon surface. Interestingly, the PACs thermally deoxidized in N2 atmosphere optimized their properties, e.g. increasing their zeta values and decreasing the oxygen content which accelerated the BrO3- removal rate. The maximum adsorption capacity of fruit-based carbon was the highest among all tested carbons （99.6 mg/g）, possibly due to its highest pore volume. Remarkably, the thermal regeneration of PACs in N2 atmosphere could completely recover the adsorption capacity of PACs. The kinetic data obtained from carbons was analyzed using pseudo second-order and intraparticle diffusion models, with results showing that the intraparticle diffusion was the more applicable model to describe adsorption of BrO3- onto PACs.

Removal of phenol by powdered activated carbon adsorption

In this study, the adsorption performance of powdered activated carbon （PAC） on phenol was investi- gated in aqueous solutions. Batch adsorption studies were performed to evaluate the effects of various experimental parameters like PAC type, PAC dose, initial solution pH, temperature and pre-oxidation on the adsorption of phenol by PAC and establish the adsorption kinetics, thermo- dynamics and isothermal models. The results indicated that PAC adsorption is an effective method to remove phenol from water, and the effects of all the five factors on adsorption of phenol were significant. The adsorption rate of phenol by PAC was rapid, and more than 80% phenol could be absorbed by PAC within the initial 10 min. The adsorption process can be well described by pseudo- second-order adsorption kinetic model with rate constant amounted to 0.0313, 0.0305 and 0.0241 mg.μg .min -1 with coal, coconut shell and bamboo charcoal. The equilibrium data of phenol absorbed onto PAC were analyzed by Langmuir, Freundlich and Tempkin adsorp- tion isotherms and Freundlich adsorption isotherm model gave the best correlation with the experimental data. Thermodynamic parameters such as the standard Gibbs free energy （△G0）, enthalpy （△H0） and entropy （△S0） obtained in this study indicated that the adsorption of phenol by PAC is spontaneous, exothermic and entropy decreasing.