White Precipitate Research Articles

The Effect on the Reaction Rate By the Binder Contact with the Cathode Active Material for 2V Class Water Based Lithium Ion Battery

Introduction Batteries with high electromotive force using aqueous electrolyte solution have been developed by the control of the Hydrogen and Oxygen overvoltage. Leclanche in 1866, manganese dioxide cathode active material, zinc anode active material, and ammonium chloride aqueous solution were applied as a Leclanche battery since zinc is well known as the suitable material of which having high hydrogen overvoltage to overcome the 1.23 V restriction of the water decomposition. Further break through on higher output voltage was achieved by applying PbO2 as the cathode material of lead-acid battery due to its high oxygen overvoltage. Similar point of view may be taken into account as a key point in the development on water-based lithium batteries. The binders commonly used in the conventional lithium ion batteries are polyvinylidene fluoride and polyacrylonitrile, they may work fine as the water based lithium batteries with similar functions. Thus we examined them from the view point of the overvoltage. Experimental The two electrode cells for testing cathode active material of 2V-class water based lithium-ion battery were prepared by the following procedure. Cathode active material of LiNi1/3Mn1/3Co1/3O2 (NMC), PVDF as the binder, and acetylene black conducting reagent were mixed to be as the cathode slurry. Aluminum or titanium were used as the current collector, and zinc was used as an anode. Charging/discharging performance in 6M LiNO3 aqueous electrolyte solution was evaluated by cyclic voltammetry at a sweep rate of 0.5 mV/s. To elucidate the effect of binder, the gold wire only and NMC implanted on gold wire were prepared by coated with and without PVDF, butyral resin, SBR binders, and used as the working electrode. The counter electrode of SUS and Ag/AgCl reference electrode were used for three-electrode cell with 6M LiNO3 aqueous electrolyte solution, and the electrochemical reaction was evaluated by cyclic voltammetry at a sweep rate of 5 mV/s. Results and Discussions For the case of Al current collector, the open circuit voltage of about 2.0 V was observed after charging. However, the gas evolution, probably oxygen evolution, from the electrode surface is observed, and the reaction current became unstable due to come unstuck of active material composites from Al current collector. The pH of electrolyte solution increased from 6 to 12 during the discharging, and this may be decreased the stability of Al. During the discharging, white precipitate was observed on zinc anode and this may be attributed to Zn(OH)2. To prevent these unstable situation, the current collector was changed from Al to Ti, and the results were fine as i) oxygen evolution was suppressed, ii) unstuck of active material composites was suppressed, iii) reaction current became stable. Clearly, it was concluded that the use of Ti was the promising current collector for the 2V class water based lithium-ion battery. According to the three-electrode cell measurement, only the case of PVDF binder showed clear charging/discharging current, whereas the other case did not show any charging/discharging current. As a conclusion, the choice of Ti as the current collector and the PVDF as the binder was suitable for 2V class water based lithium-ion battery.

Synthesis of Gallium Nitride Photocatalysts By Reaction of Solution Synthesized Gallium Oxide and Solid Nitrogen Sources

Solar energy-driven water splitting is receiving considerable interest in hydrogen production as a renewable energy source. Various semiconductor materials for the photodecomposition of water have been investigated for solar energy conversion such as TiO2, TaON and BiVO4. GaN, GaN : ZnO and GaN : InN solid solution are also considered as the photoelectrochemically active material for solar energy-driven water splitting. And its band gap can be controlled by the composition of these solid solutions. We have reported a new technique to synthesize low cost GaN powder under moderate condition, Li3N or LiNH2 were used as a high reactive solid nitrogen source to improve the reaction rate and lowering the reaction temperature. A high yield and high purity GaN with wurtzite structure was synthesized [1, 2]. In this report we studied the method to synthesize GaN powders by the reaction of solution synthesized Ga2O3 powder with solid nitrogen sources. In previous reports commercially available Ga2O3 powder was used. When commercial Ga2O3 powder was used, by the inhomogeneous size, the reaction occurred partially and the yields became small. So the gallium oxide powder with homogeneous size was synthesized by the use of solution process. The photoelectrochemical properties of particulate electrode with synthesized GaN powder were also investigated. The GaCl3 was dissolved in 2-buthyl alcohol under stirring. Then the purified water was added gradually to the Ga containing solution to get the white precipitate. XRD analysis demonstrate that the synthesized powder is Ga2O3. The crucible with starting materials, Ga2O3 and Li3N were put into a sealed stainless steel reaction vessel and it was set vertically in an electric furnace. Then it was heated at 550 – 700°C, 2 hours in N2 atmosphere. After the reaction, the products were washed by alcoholic HCl solution and distilled water. Crystalline wurtzite GaN powder with several hundred nanometer size was successfully synthesized. The reaction yield for the GaN synthesis with solution processed Ga2O3 is higher than that with commercial Ga2O3 powder. Anodic photocurrent was clearly observed for the paste electrodes with GaN and this observation indicates that the GaN synthesized in this study shows n-type semiconductivity. GaN : InN solid solution was also successfully synthesized by the reaction with GaCl3, InCl3 and LiNH2. Photo-electrochemical properties of its paste electrode was also studied. References T. Zhang, A. Mabuchi, T. Sugiura, H. Minoura, Trans. Mater. Res. Soc. Jpn., 33(4), 1277-1280 (2008).T. Zhang, A. Kouyama, M. Miura and T. Sugiura, Trans. Mater. Res. Soc. Jpn., 36(3), 513-516 (2011).

Effect of hydrothermal process for inorganic alumina sol on crystal structure of alumina gel

This paper reports the effect of a hydrothermal process for alumina sol on the crystal structure of alumina gel derived from hydrothermally treated alumina sol to help push forward the development of low temperature synthesis of α-Al2O3. White precipitate of aluminum hydroxide was prepared with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution. The obtained aluminum hydroxide precipitate was peptized by using acetic acid at room temperature, which resulted in the production of a transparent alumina sol. The alumina sol was treated with a hydrothermal process and transformed into an alumina gel film by drying at room temperature. Crystallization of the alumina gel to α-Al2O3 with 900 °C annealing was dominant for a hydrothermal temperature of 100 °C and a hydrothermal time of 60 min, as production of diaspore-like species was promoted with the hydrothermal temperature and time. Excess treatments with hydrothermal processes at higher hydrothermal temperature for longer hydrothermal time prevented the alumina gel from being crystallized to α-Al2O3 because the excess hydrothermal treatments promoted production of boehmite.

Novel Mesoporous Microspheres of Al and Ni Doped LMO Spinels and Their Performance As Cathodes in Secondary Lithium Ion Batteries

1. Introduction – Lithium manganese oxides (LMO) based spinels are important cathode materials for Lithium ion batteries (LIBs). However the primary problem of these electrodes are that they suffer structural deformation owing to the Jahn-Teller distortion[1]. This reduces their lifetime and the efficiency of the battery greatly reduces with cycling. However, some improvement have been obtained by adding transition metals and/or modifying the surface area of the electrode materials. This abstract focuses on developing novel porous Ni and Al based LMO microstructures for LIB applications[2]. 2. Experimental fabrication – The LMO fabrication is done from their precursors. Initially MnCO3 microspheres are obtained from NaHCO3 and MnSO4.H2O precursors. This reaction is done in the liquid phase and once the two precursors are mixed, immediate formation of a white precipitate is noticed. Once this is obtained, the MnCO3 hollow spherical precursors are then reacted with LiOH by solid state reaction technique in stoichiometric amounts to obtain the LiAl0.1Mn1.9O4 (LAMO) and LiAl0.1Ni0.1Mn1.8O4 (LANMO) microspheres. 3. Results –Charge-discharge analysis have been performed at a constant current density of 0.5 mAcm-2by an Arbin instrument up to 4.5 V and discharged to 2V. The discharge curves follow the characteristic pattern of the LMO spinel based compounds. A phase changes is noticed during the discharge process, at ~ 4.1 V and ~ 2.75 V corresponding to the kink in the discharge. The second phase change at ~ 2.75 V is due to theJahn-Teller effect which produces a permanent deformation of the crystal lattice and steady loss of capacity. The maximum discharge capacity of the LAMO sample is 122.51 mAhg-1 and 75th cycle discharge capacity is 42.22 mAhg-1. The LANMO sample provides a 1st cycle discharge capacity of 140.49 mAhg-1 and a 75th cycle discharge capacity of 66.24 mAhg-1. The LANMO system is seen to be superior in performance as compared to the LAMO system. This is due to the stabilizing role that the added Ni has provided to the crystal lattice, improving the cathodes ability to perform stable intercalation. The performance of these electrodes is demonstrated in Figure 1(a-c). 4. Conclusions – This research provides an insight in to the study of spinels at relatively low voltages which is not so prevalent in the literature. Also a novel technique is used to produce highly porous LMO based spinel spheres which serve to have enhanced electrochemical capacity and cell performance.

Synthesis of luminescent KY3F10 nanopowder multi-doped with lanthanide ions by a co-precipitation method

A series of KY3F10 nanophosphors doped with Gd3+, Ce3+ and Eu3+ ions were obtained with the use of a co-precipitation method. The resulting products were white precipitates, consisting of spherical particles with diameter about 150–200 nm, which was confirmed using transmission electron microscopy (TEM) technique. Powder X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX) measurements confirmed appropriate structures of the nanoparticles obtained. Spectroscopic properties of the products were examined on the basis of the measured excitation/emission spectra and luminescence decay curves. The synthesized samples showed orange-red luminescence, characteristic for Eu3+ ions. The reaction process was performed in required alkaline pH adjusted with the use of ethylenediaminetetraacetic acid (EDTA) and potassium hydroxide. The samples containing large amounts of Gd3+ dopant ions exhibited a tendency to form products with different morphologies.

A two-center study for the quality control of [(18)F]FDG using FASTlab phosphate cassettes.

The GE FASTlab radiosynthesis module is routinely used for the production of [(18)F]FDG, utilizing the commercially available phosphate cassettes. Because of the observation of a white precipitate in the product vial before the product expiry time, we re-examined the quality of the produced [(18)F]FDG solution. Phosphate buffered [(18)F]FDG solution was synthesized on the FASTlab and analyzed at both National Taiwan University Hospital (NTUH) of Taiwan and Royal Brisbane and Women's Hospital (RBWH) of Australia. In addition to the standard product quality control (QC), the concentration of aluminum (Al(3+)) as probable cause of the precipitations in the [(18)F]FDG solution was analyzed by inductively coupled plasma mass spectrometry (ICP-MS at RBWH) and inductively coupled plasma optical emission spectrometry (ICP-OES at NTUH), and using three semi-quantitative methods at NTUH, Advantec(®) Alumi Check Test Strip, Quantofix(®) Aluminum Test Strip and MColortest™ Aluminum Test kit. The precipitates were observed in the [(18)F]FDG solution within 24 (NTUH) and 6 (RBWH) hours after the end of synthesis in 38-100% of the batches, dependent on the batch of the FASTlab cassettes. Addition of metal-free HCl(aq) to aliquots of [(18)F]FDG containing precipitate, followed by ICP-MS analysis revealed Al(3+) concentrations of 70-80ppm. Al(3+) concentrations of 10-12ppm were detected in [(18)F]FDG batches that did not show any precipitation. In contrast, less than 5ppm of the residual Al(3+) was detected by semi-quantitative methods in all batches. The US (USP), British (BP), European (EP) and Japanese (JP) pharmacopeias demand that [(18)F]FDG for injection should be clear and particulate free within the given shelf-life/expiration time. To avoid Al-phosphate precipitation within the product expiry time, FASTlab citrate cassettes, rather than phosphate cassettes, should be used for [(18)F]FDG production. Although testing for Al(3+) is not listed in the [(18)F]FDG monographs of the USP, BP and EP, residual Al(3+) levels should be considered in the interests of patient safety.

Chemical distribution of hazardous natural radionuclides during monazite mineral processing

It is very important to calculate the radioactivity concentration for low-grade monazite ore (50%) and different other materials produced as results of chemical processing stages to avoid the risk to workers. Chemical processing of low-grade monazite pass through different stages, washing by hydrochloric acid and digested with sulfuric acid and influence of pH on the precipitation of rare earth elements has been studied. The radioactivity concentrations of 238U(226Ra) and 232Th as well as 40K were calculated in crude low-grade ore and found to be 54,435 ± 3138, 442,105 ± 29,200 and 5841 ± 345 Bq/kg, respectively. These values are greatly higher than the exempt levels 25 Bq/kg. After chemical digestion of the ore, the results demonstrated that un-reacted material contains significant radioactivity reached to approximately 8, 13 and 23% for 238U, 232Th and 40K, respectively. The results show that 60% of 232Th are located in the digested white slurry with small portions of 238U and 40K. Most of 238U radioactivity is extracted in the green phosphoric acid which produced from conversion of P2O5 by H2SO4 into phosphoric acid. The average values of the Raeq for monazite ore, un-reacted black precipitate, white precipitate, brown precipitate and crystalline material samples were calculated and found to be 687,095 ± 44,921, 85,068 ± 5339, 388,381 ± 22,088, 313,046 ± 17,923 and 4531 ± 338 Bq/kg, respectively. The calculated values of Raeq are higher than the average world value (it must be less than 370 Bq/kg). Finally the external hazardous, internal hazardous and Iγr must be less than unity. This means that specific radiation protection program must be applied and implemented during monazite processing.

Chronic Recurrent Pseudophakic Endophthalmitis

An immunocompetentwoman in her 80s underwent uncomplicated cataract surgery in her righteye4monthspriorwithbest-correctedvisualacuity (BCVA)of20/25OD.Twoweeks prior topresentation, shereportedagradual increase inblurredvisionwith intermittent floaters in the right eyebut deniedpain or inciting events.HerBCVAwas20/50OD. Therewere large keratic precipitates, 1+ anterior chamber cell and flare, and no hypopyon. Numerous white precipitates were noted on the anterior and posterior surface of a 3-piece posterior chamber intraocular lens (Figure, A). Therewere 2+ to 3+ anterior vitreous cells and a 2–disc area chorioretinal scar along the superior retinal arcadeswith extramacular drusen, but no areasof chorioretinitis (Figure, B). B-scanultrasonography showedaposterior vitreousdetachmentandmoderatevitreousopacities.Thecontralateralphakiceyeshowedsimilardrusen but was otherwise unremarkable. The patient underwent a vitreous tap,whichwas negative for organisms, aswell as injection of intravitreal vancomycin hydrochloride and ceftazidime in the right eye. Topical prednisolone acetate and ofloxacin were started 4 times daily, and steroids were increased toevery2hourswhile awakeat follow-up.HerBCVA improved to20/30OD4days later. TheBCVAremainedexcellent andkeraticprecipitatesdissipatedby 1monthof followup, with stable findings in the posterior pole. Topical antibiotics were stopped and topical steroidswere gradually tapered. At 2months’ follow-up, however, she had recurrent anterior chamber and vitreous inflammation with mild cystoid macular edema. Quiz at jamaophthalmology.com Fundus photograph B Slitlamp photograph A

Wet Chemically Synthesized CuO Bipods and their Optical Properties.

Metal oxide nanostructures are being investigated widely due to their strong optical absorption, efficient photoluminescence, abundant of availability and structural stability which lead them as a possible substitute of Si based solar cells and many optoelectronic and sensor devices. Due to their non-toxic nature they are supposed to be promising materials for drug delivery and medical research. Among several metal oxides, cupric oxide (CuO) is being investigated nowadays due to their high transparency and visible luminescence. It is a p-type semiconductor of band gap varying from 1.3 eV to 2.1 eV depending of the structure and process of fabrication. This low band gap of CuO nanostructures leads its application in photoconductive and photothermal applications. This leads rigorous investigations on CuO nanostructures. A simple wet chemical methods has been used to synthesize CuO bipods. Predetermined amount of Copper sulphate penta-hydrate (CuSO4, 5H2O) was dissolved in double distilled de-ionized water to prepare 0.5 M solution. Predetermined amount of Lithium hydroxide (LiOH) was dissolved in de-ionized water to prepare 1 M solution. Under rigorous magnetic stirring of the LiOH solution CuSO4 solution was added drop by drop for five minutes and the stirring was maintained for 2 hours at room temperature (30°C). After the reaction a white precipitate was observed at the bottom of the flask. This solution was then aged for 24 hours. The color of the precipitate solution was turned into grey. The precipitate was filtered and subsequently washed with distilled de-ionized water thrice for the removal of unreacted salts if any. The precipitate was then dried in an ordinary furnace at 150°C for further characterization. X-ray diffraction data confirmed the formation of well crystalline CuO having monoclinic unit cell structure. The crystallite size was ~ 12 nm as calculated from the XRD pattern. Transmission electron microscope images revealed that the bipod-like structure is composed of several crystallites. The lengths of the bipods are ~ 300 nm with a waist size ~ 100 nm. The UV-visible spectroscopic data revealed a strong absorption at ~ 376 nm and the band gap was calculated to be 2.51 eV. FTIR spectrum revealed the existence of only Cu=O bonds. In the Raman shift data two strong peaks were found at 273 cm-1, and 608 cm-1 that owe to the Ag mode and Bg mode respectively. Room temperature photoluminescence spectroscopy revealed that the CuO nanoparticles exhibit broad strong emission at ~ 472 nm. After decomposing we observed three peaks at 436, 469 and 495 nm. The emission peak at 469 nm arises due to near band edge transition. The emission peak at 495 nm arises due to shallow level defect states related transitions. In conclusion, we have fabricated CuO nano-bipods using a simple wet chemical method. XRD pattern indicates the formation of well crystalline and pure CuO without any impurity. The nano-bipods exhibit sharp absorption peak at ~ 376 nm with optical band gap energy of 2.51 eV. FTIR spectrum and Raman shift data confirms the formation of CuO with the presence of Ag mode (273 cm-1) and Bg mode (608 cm-1). The fabricated CuO nano-bipods exhibit strong PL emission at 469 nm owing to the recombination of free excitons at the absorption band edge in the UV region associated with other low intense deep level emission. Few relevant patents to the topic have been reviewed and cited.

Electrospinning of GeO2–C fibers and electrochemical application in lithium-ion batteries

Abstract GeO2–C fibers were successfully synthesized using electrospinning homogeneous sol and subsequent calcination in an inert atmosphere. The spinnable sol was prepared by adding polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) in a weight ratio of 1:1 into a mixture with white precipitate produced by dropping GeCl4 into DMF. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the as-obtained fibers, and electrochemical tests were conducted to measure electrochemical performance of the electrode. The electrospun fibers have uniform diameters of ∼300 nm. After being calcined at 600 °C for 2 h in Ar, they transform to amorphous GeO2–C fibers with the same morphologies. The GeO2–C fibers exhibit excellent cycling stability with a high reversible capacity of 838.93 mA h g−1 after 100 cycles at a current density of 50 mA g−1, indicating the composite fibers could be promising anode candidates for lithium-ion batteries.

Performance of Inclined Baffle Column for Pectin Continuous Extraction Process from Cocoa Peel (Theobromacacao)

Pectin from cocoa peel was successfully prepared by extraction method in the bubble column reactor. The process could be carried out in batch and continuous, with co-current or counter current flow. Bubble pipe reactor with inclined baffle is expected to reduce the problem from gas flow patterns, jagged sloping bulkhead serves as a bubble breaker that could replace mechanical stirrer. In this study the reactor column sloping bulkhead was used as extractor to recover pectin in the cocoa peel by citric acid (1 N) solvent. Cocoa peel paste and citric acid were entered to the top of the column at 1 : 1 rate ratio by streamed using dosing pump. Nitrogen gas as a medium stirrer flowed counter current from the bottom of the column. Once extraction was completed, the liquid then precipitated by acid alcohol. Pectin solids were washed with alcohol (96%). The temperature of extraction process is maintained at 70° C. The residence time in the column material was determined by feed flow rate (cocoa paste and citric acid), and the volume of suspension that remains in the reactor (V). Residence time equation obtained is: t = (7045.86G -0.1275 )/L. The yield of yellowish white precipitate reached up to 5.2973% and methoxyl concentration reached 5,21% for 72 minutes. The experiment shows that the continuous extraction process of pectin in baffle columns is better than batch process.

Efficiency of concrete crack-healing based on biological carbonate precipitation

The aim of this study was to improve the capacity for crack-repair in concrete by developing a new way. The self-healing agent based on biological carbonate precipitation was developed. Crack-healing capacity of the cement paste specimens with this biochemical agent was researched. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the precipitation in cracks. The healing efficiency was evaluated by measuring the water permeability after crack healing as well.The experimental results show that the applied biochemical agent can successfully improve the self-healing capacity of the cement paste specimens as larger cracks can be healed. The cracks with a width of 0.48 mm in the specimens with the biochemical agent are nearly fully healed by the precipitation after 80d repair. SEM and XRD analysis results demonstrate that the white precipitation in cracks is calcium carbonate, which displays spherical crystal morphology. Meanwhile, the water permeability test result shows that the biochemical agent can significantly decrease the water permeability of the cement paste specimens, the water permeability of specimens with the biochemical agent respectively decreases by 84% and 96% after 7 d and 28 d immersion in water, however the control specimens only respectively decrease by 41% and 60%, which indicates that the bacteria-based concrete appears to be a promising approach to increase concrete durability.

No‐Lead Brass Service Valve Performance in Colorado River Water

In accordance with the Reduction of Lead in Drinking Water Act, no‐lead (<0.25%) brass service valves must now be installed for new connections or as replacements throughout distribution systems. In this study, no‐ and low‐lead (<8%) red brass corporation stops and angle‐meter service valves were evaluated for 10 months using a flow‐through pipe rig with treated Colorado River water. In both no‐ and low‐lead valves, the fraction of tin increased from a minor (<10%) to a major (>40%) element on the wetted interior surface. Corrosion changes were consistent across valve and material types, except for the formation of a white precipitate of lead on the external surface of low‐lead angle‐meter valves and nonwetted fittings. Copper enrichment from potential dezincification was identified in the pack joint fitting crevice of the angle‐meter valves. Changing to no‐lead brass is not anticipated to result in increased service valve failure rates.

The [closo-B12H11-1-IAr]− zwitterion as a precursor to monosubstituted derivatives of [closo-B12H12]2−

Reactions of [closo-B12H12]2− with ArI(OAc)2 in aqueous AcOH in the presence of [NEt4]+ or [NHEt3]+ give [closo-B12H11-1-IAr]− (1) in 74–95% yield as a white precipitate. The zwitterions decompose in CD3CN solutions with rates k = 3.30 ± 0.04 × 10−4 s−1 (Ar = Ph, 1a[NEt4]) and k = 1.96 ± 0.01 × 10−4 s−1 (Ar = C6H4OMe-4, 1b[NEt4]) at 0 °C. Reactions of the zwitterion with Me2NCHS and pyridine gave the corresponding products [closo-B12H11-1-SCHNMe2]− (2) and [closo-B12H11-1-NC5H5]− (3) isolated in 25–27% and up to 44% yield, respectively. The former anion is a protected thiol derivative, which was transformed to the sulfonium derivative [closo-B12H11-1-S(CH2)5]− (8). The molecular structure and spectroscopic properties of pyridinium zwitterion 3 were analyzed experimentally and computationally (B3LYP), and results compared with those for the [closo-B10H9-1-NC5H5]− (4) analog. Mechanisms of formation of 2–4 from appropriate aryliodonium zwitterions were analyzed with the M062x computational method.

Fungi Isolated from Maize (Zea mays L.) Grains and Production of Associated Enzyme Activities.

Filamentous fungi produce a great variety of enzymes, and research on their biotechnological potential has recently intensified. The objective of this work was to identify, at the species level, using DNA barcoding, 46 fungal isolates obtained from maize grains with rot symptoms. We also analyzed the production of extracellular amylases, cellulases, proteases and lipases of 33 of those fungal isolates. The enzymatic activities were evaluated by the formation of a clear halo or a white precipitate around the colonies in defined substrate media. The found fungi belong to the genera Talaromyces, Stenocarpella, Penicillium, Phlebiopsis, Cladosporium, Hyphopichia, Epicoccum, Trichoderma, Aspergillus, Irpex, Fusarium, Microdochium, Mucor and Sarocladium. In the genus Fusarium, the species Fusarium verticillioides was predominant and this genus presented the highest diversity, followed by the genera Aspergillus. The best genera for lipase production were Cladosporium and Penicillium; while Cladosporium, Aspergillus and Penicillium were best for cellulase activity; Hyphopichia, Aspergillus and Irpex for amylase activity; and Cladosporium and Sarocladium for proteases activity. In conclusion, a collection of fungi from maize seeds presenting rotten symptoms were obtained, among which exist important producers of hydrolases.

The effects of temperature and agitation speed on the leaching behaviors of tin and bismuth from spent lead free solder in nitric acid leach solution

Nitric acid leaching was performed to separate tin and bismuth in spent Pb-free solder. The effects of agitation speed and leaching temperatures on the leaching behaviors of tin and bismuth were investigated to recover tin and bismuth from the spent solder, respectively. The leaching efficiency of bismuth increased rapidly with increasing agitation speeds and temperatures, and the efficiency is found to be 97.8% under the following leaching conditions: nitric acid concentration of 1 k mol m− 3, agitation speed of 400 rpm, 1% pulp density, leaching temperature of 90°C, leaching time of 1 hour. In the case of tin, the leaching efficiency increased and then decreased during leaching tests, and a white precipitate was observed in the reactor. XRD results indicate that tin precipitated as stannic acid (SnO2 H2O). Consequently, bismuth and tin could be separated successfully by nitric acid leaching process.

APPLICATION OF NONINVASIVE PREGNANCY DIAGNOSIS IN BACTRIAN CAMELS (CAMELUS BACTRIANUS) USING CUBONI REACTION AND BARIUM CHLORIDE TEST.

Pregnancy diagnoses in half-tamed animals are often very complicated. This study aimed to examine the alternative noninvasive and cheap methods of pregnancy diagnosis from urine in domestic Bactrian camels (Camelus bactrianus). Urine from 14 female camels kept in four European zoologic gardens was collected and tested by two chemical tests--Cuboni reaction and barium chloride test. The Cuboni reaction was significantly (P<0.01) affected by the pregnancy status of female camels. The total accuracy of the Cuboni reaction was 70.5% but it increased significantly (P<0.05) in the time leading up to parturition. The accuracy was 100% in the 3rd third of pregnancy. Urine of nonpregnant females did not react with a solution of barium chloride while, contrary to other studies, white precipitates formed mostly (80 to 100%) in urine of pregnant females. This study concluded that the Cuboni reaction is applicable for pregnancy diagnosis in camels.

선박용 SCR 시스템 NOx 측정 및 분석 방식의 특성 연구

A method for measuring and analyzing the NOx in ships is described in NOx Technical Code 2008. The analysis device, as required by the Code, has been to use a Chemi-luminescence detection method or Heated Chemi-luminescence detection. on the other hand, selective catalytic reduction using NH3 as a reducing agent has an interference effect on the analyzer, and causes measurement error. In this study, the Chemi-luminescence detection method was examined according to how it affects the concentration of O2, CO, SO2, NH3. Fourier transform infrared spectrometry analysis equipment and measurement methods were compared. In order to confirm the effect of the physical interference of the measuring device, it was confirmed by decomposing a measuring device. Consequently, white precipitate and moisture were generated inside the chemiluminescence detection system and I found that affecting interference. The influence of interference highlights the need to consider the minimized NOx measurement method.

Switchable Spherical-Wormlike Micelle Transition in Sodium Oleate/N-(3-(Dimethylamino)propyl)-Octanamide Aqueous System Induced by Carbon Dioxide Stimuli and pH Regulation

The structure transitions of the aggregates in the sodium oleate (NaOA)/N-(3-(dimethylamino)propyl)-octanamide (DPOA) aqueous system was investigated upon CO2 stimuli. During the process of bubbling of CO2, three appearance states of sol, gel, and emulsion with little white precipitate were observed continuously. The cryo-transmission electron microscope characterization and rheological measurements exhibited that the sol–gel transition was attributed to a spherical-wormlike micelle transition. Moreover, this transition was switchable at least three cycles in the pH range of 10.91–9.56 by CO2 stimuli and pH regulation (adding NaOH), which could be explained by the protonation of DPOA and deprotonation of DPOA · H+. Bubbling of CO2 resulted in protonation of DPOA, which not only inserted into the OA– as a co-surfactant but also screened the electrostatic repulsion among OA–, corporately leading to the spherical-wormlike micelle transition. Adding NaOH caused the deprotonation of DPOA · H+ and hence reversed this transition. This surfactant system with switchable micelle transition not only displays tremendous application potential in various fields but also is of key importance in cyclic utilization of surfactant.

Perfluoro-alcohol-induced complex coacervates of polyelectrolyte-surfactant mixtures: phase behavior and analysis.

Perfluorinated alcohols and acids such as hexafluoroisopropanol (HFIP), trifluoroethanol, trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid induce coacervation and phase separation in aqueous solutions of a wide variety of individual and mixed amphiphiles [ Khaledi Langmuir 2013 , 29 , 2458 ]. This paper focuses on HFIP-induced complex coacervate formation in the mixtures of anionic polyelectrolytes, such as sodium salt of poly(methacrylic acid) (PMA) or poly(acrylic acid) (PAA) and cationic surfactants of alkyltrimethylammonium bromides. In purely aqueous media and over a wide concentration range, mixtures of PMA and CTAB form the catanionic complex (CTA(+)PM(-)) that is insoluble in water (white precipitate). Upon addition of a small percentage of HFIP, the mixture goes through phase transition and formation of two distinctly clear liquid phases. The phase diagram for the HFIP-PMA-CTAB coacervate system was studied. The coacervate volume was determined as a function of system variables such as charge ratio as well as total and individual concentrations of the system components. These results, combined with the chemical composition analysis of the separated aqueous top-phase and coacervate bottom-phase, shed light on the coacervation mechanism. The results suggest that exchange of counterions and ion-pair formation play critical roles in the coacervation process. This process facilitated by HFIP through solvation of the head groups and dehydration of the hydrophobic moieties of the catanionic complex. Because of the presence of HFIP, coacervation occurs over a wide range of concentrations and charge ratios of the oppositely charged polyelectrolyte and surfactant.