Abstract  This paper presents a proprietary process developed to manufacture organic montmorillonite (OMMT)- reinforced and isocyanate (-NCO) -blocked pouring-type polyurethane (BPPU) nanocomposites. The BPPU polymer was prepared from phenol- blocked blends of toluene diisocyanate (TDI), polyethylene glycol and 3,3'-dichloro-4,4'-diamido diphenyl methane (MOCA). The physical and mechanical properties of OMMT reinforced BPPU composites have been studied. BPPU samples containing 4 phr OMMT exhibited excellent mechanical properties because of the exfoliation and intercalation of the organic silicate layers.

Abstract  The printed circuit board (PCB) is an important part of electrical and electronic equipment, and its disposal and the recovery of useful materials from waste PCBs (WPCBs) are key issues for waste electrical and electronic equipment. Waste PCB compositions and their pyrolysis characteristics were analyzed in this study. In addition, the volatile organic compound (VOC) exhaust was controlled by an iron-impregnated alumina oxide catalyst. Results indicated that carbon and oxygen were the dominant components (hundreds mg/g) of the raw materials, and other elements such as nitrogen, bromine, and copper were several decades mg/g. Exhaust constituents of CO, H2, CH4, CO2, and NOx, were 60-115, 0.4-4.0, 1.1-10, 30-95, and 0-0.7mg/g, corresponding to temperatures ranging from 200 to 500°C. When the pyrolysis temperature was lower than 300°C, aromatics and paraffins were the major species, contributing 90% of ozone precursor VOCs, and an increase in the pyrolysis temperature corresponded to a decrease in the fraction of aromatic emission factors. Methanol, ethylacetate, acetone, dichloromethane, tetrachloromethane and acrylonitrile were the main species of oxygenated and chlorinated VOCs. The emission factors of some brominated compounds, i.e., bromoform, bromophenol, and dibromophenol, were higher at temperatures over 400°C. When VOC exhaust was flowed through the bed of Fe-impregnated Al2O3, the emission of ozone precursor VOCs could be reduced by 70-80%.

Abstract  Diphenyl carbonate (DPC) is considered as a substitution for phosgene to synthesize polycarbonate resins. Conventional production of DPC involves reactions of phosgene and phenol. However, the phosgene process has drawbacks such as environmental and safety problems associated with using highly toxic phosgene as the reagent, which results in the formation of chlorine salts, and copious amounts of methylene chloride as the solvent. For these reasons, environmentally friendly processes for DPC production without using phosgene have been proposed and developed in the past decades. So far, the most promising alternatives appear to be the transesterification of dimethyl carbonate (DMC) and phenol, the direct oxidative carbonylation of phenol, and transesterification of dialkyl oxalates and phenol. This paper attempts to review recent literature concerning process design and catalytic chemistry for these phosgene-free approaches. The advantages and disadvantages are discussed for each reaction. Strategies to overcome potential problems are provided. The perspectives to improve catalytic efficiency of phosgene-free process are proposed. (c) 2006 Elsevier B.V. All rights reserved.

Abstract  Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench‐top reactors and in serum bottle tests. Three continuously mixed daily batch‐fed reactor systems were evaluated: anaerobic, aerobic, and sequential‐anaerobic‐aerobic (sequential). Glucose, acetate, benzoate, and phenol were fed as growth substrates to both the anaerobic and aerobic systems. Methane and toluene were also added to the aerobic systems to induce cometabolic degradation of the feed CACs. The anaerobic culture degraded seven of the feed CACs. The specialized aerobic cultures degraded all but three of the highly chlorinated CACs. The sequential system outperformed either of the other systems alone by degrading 10 of the feed CACs: chloroform, carbon tetrachloride, 1,1‐dichloroethane, 1,1,1‐trichloroethane, hexachloroethane, 1,1‐dichloroethylene, trans‐1,2‐dichloroethylene, trichloroethylene, perchloroethylene, and 1,2,3‐trichloropropane, plus the anaerobic metabolites: dichloromethane and cis‐1,2‐dichloroethylene. Sequential treatment did not show significant removal of 2‐chloropropene, or 1,1‐dichloropropene. Cultures from each of the reactors were used in bottle tests to determine relative CAC degradation rates. Maximum degradation rates observed for individual CACs ranged from 20 to 150 μg per gram volatile suspended solids per day.

Abstract  Seven aliphatic dicarboxylic acids (C3-C9) along with phthalic acid, pinic acid and pinonic acid were determined in 35 aerosol (PM10) samples collected over the year at Vavihill sampling station in south of Sweden. Mixture of dichloromethane and methanol (ratio 1:3) was preferred over water for extraction of samples and extraction was assisted by ultrasonic agitation. Analytes were derivatized using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) containing 1% trimethylsilyl chloride and analyzed using gas chromatography/mass spectrometry. Among studied analytes, azelaic acid was found maximum with an average concentration of 6.0 plus or minus 3.6 ng m super(-3) and minimum concentration was found for pimelic acid (1.06 plus or minus 0.63 ng m super(-3)). A correlation coefficients analysis was used for defining the possible sources of analytes. Higher dicarboxylic acids (C7-C9) showed a strong correlation with each other (correlation coefficients (r) range, 0.96-0.97). Pinic and pinonic acids showed an increase in concentration during summer. Lower carbon number dicarboxylic acids (C3-C6) and phthalic acid were found strongly correlated, but showed a poor correlation with higher carbon number dicarboxylic acids (C7-C9), suggesting a different source for them. Biomass burning, vehicle exhaust, photo-oxidation of volatile organic compounds (natural and anthropogenic emissions) were possible sources for dicarboxylic acids.

Abstract  The feasibility of the enhanced immunization with diphtheria toxoid-loaded bioerodible microspheres was examined by investigating the serum antibody levels and lethal test in vivo. PLGA polymer was selected based on the properties such as degradability, tissue compatibility, and ease of particulate preparation. The double emulsion solvent extraction method was employed for the fabrication of microspheres to control the release of diphtheria toxoid. Dichloromethane or ethyl acetate was applied as an organic phase and poly (vinyl alcohol) as a secondary emulsion stabilizer during fabrication procedure. Diphtheria toxoid can be microencapsulated using PLGA copolymer without a loss of its immunogenicity. The results from the in vivo study with bioerodible microsphere indicated that immunogenic response, expressed as ELISA IgG titers, was significantly higher than the conventional antigen for 8 weeks after single injection. Consequently, these microspheres could provide the controlled release of antigens for developing enhanced vaccine formulations as a parenteral carrier system.

Abstract  In this research, the quality of drinking well waters from 14 districts around Seoul metropolitan city, Korea was assessed by measuring a number of parameters with established guideline (e.g., arsenic, fluoride, nitrate nitrogen, benzene, 1,2-dichloroethene, dichloromethane, copper, and lead) and without such criteria (e.g., hardness, chloride ion, sulfate ion, ammonia nitrogen, aluminum, iron, manganese, and zinc). Physical parameters such as evaporation residue (or total dissolved solids) and turbidity were also measured. The importance of each parameter in well waters was examined in terms of the magnitude and exceedance frequency of guideline values established by international (and national) health agencies. The results of this study indicate that among the eight parameters with well-established guidelines (e.g., WHO), arsenic and lead (guideline value of 0.01 mg L(-1) for both) recorded the highest exceedance frequency of 18 and 16 well samples ranging in 0.06-136 and 2-9 mg L(-1), respectively. As such, a number of water quality parameters measured from many well waters in this urban area were in critical levels which require immediate attention for treatment and continuous monitoring.

Abstract  Using Successive-Ionic-Layer-Adsorption-and-Reaction deposition technique, TiO2 films on polyvinyl chloride (PVC) and glass substrates were prepared. The photocatalytic and antibacterial activities of TiO2 films on PVC were evaluated by monitoring the photo-decomposition of 2-(phosphonomethylamino)acetic acid and Micrococcus lutes (odor causing bacteria). Photocatalytic degradation of methylene blue under UV source over as-made, hydrothermal and furnace annealed TiO2 films, and commercial TiO2 pellets were examined. (C) 2010 Elsevier B.V. All rights reserved.

Abstract  This study aimed to characterize spatial/ temporal variations of ambient volatile organic compounds (VOCs) using a community-scale monitoring approach and identify the main sources of concern in Paterson, NJ, an urban area with mixed sources of VOCs. VOC samples were simultaneously collected from three local source-dominated (i.e., commercial, industrial, and mobile) sites in Paterson and one background site in Chester, NJ (located similar to 58 km southwest of Paterson). Samples were collected using the EPA TO-15 method from midnight to midnight, one in every sixth day over one year. Among the 60 analyzed VOCs, ten VOCs (acetylene, benzene, dichloromethane, ethylbenzene, methyl ethyl ketone, styrene, toluene, m, p-xylene, o-xylene, and p-dichlorobenzene) were selected to examine their spatial/temporal variations. All of the 10 VOCs in Paterson were significantly higher than the background site (p < 0.01). Ethylbenzene, m, p-xylene, o-xylene, and pdichlorobenzene measured at the commercial site were significantly higher than the industrial/mobile sites (p < 0.01). Seven VOCs (acetylene, benzene, dichloromethane, methyl ethyl ketone, styrene, toluene, and p-dichlorobenzene) were significantly different by season (p < 0.05), that is, higher in cold seasons than in warm seasons. In addition, dichloromethane, methyl ethyl ketone, and toluene were significantly higher on weekdays than weekend days (p < 0.05). These results are consistent with literature data, indicating the impact of anthropogenic VOC sources on air pollution in Paterson. Positive Matrix Factorization (PMF) analysis was applied for 24-hour integrated VOC measurements in Paterson over one year and identified six contributing factors, including motor vehicle exhausts (20%), solvents uses (19%), industrial emissions (16%), mobile+ stationery sources (12%), small shop emissions (11%), and others (22%). Additional locational analysis confirmed the identified sources were well matched with point sources located upwind in Paterson. The study demonstrated the community-scale monitoring approach can capture spatial variation of VOCs in an urban community with mixed VOC sources. It also provided robust data to identify major sources of concern in the community.

Abstract  Chlorinated volatile organic compounds (CVOCs) are hazardous and potent environmental pollutants. Catalytic combustion has been regarded as one of the most promising technologies to eliminate CVOCs emissions. CH2Cl2 is difficult to be oxidized among CVOCs. A catalyst with high activity for CVOCs oxidation is desirable. In this paper, CrOx/Al2O3 catalysts with different Cr contents were prepared using a deposition-precipitation method and tested for CH2Cl2 oxidation. The highest activity was obtained over the catalyst with 18% Cr content, with a complete oxidation of CH2Cl2 at 350 degrees C. Characterization results indicated that both high oxidation state Cr species (Cr(VI) species) and crystalline Cr2O3 existed in the CrOx/Al2O3 catalysts, and the average valence of Cr species in the catalysts decreased with Cr content. It was found that the reaction rate for CH2Cl2 oxidation increased with increasing average valence of Cr, which indicated that high oxidation state Cr species were probably the active phase for the reaction. (C) 2011 Elsevier B.V. All rights reserved.

Abstract  Techniques for examining the consistency of results reported in epidemiologic and toxicologic studies were described and illustrated using methylene-chloride (75092) (MC). Data were taken from the mouse component of a longterm inhalation bioassay of MC toxicity and carcinogenicity in B6C3F1-mice and F344-rats by the National Toxicology Program (NTP) and a study of lung andliver cancer mortality among Kodak company workers exposed to MC vapor (Kodak study). The NTP study found that MC induced liver and lung cancer in mice and mammary tumors in rats. No increase in mortality from lung or liver cancer was found in the Kodak study. The techniques involved adjusting for different lengths of followup in humans versus mice using a multistage carcinogenesis riskassessment model, defining an appropriate dose metric that would produce equivalent risks for humans and mice, and calculating standardized mortality ratios (SMRs) by applying the multistage carcinogenesis model to the mouse bioassay data after adjusting the Kodak study data for the healthy worker effect. Confidence intervals (CIs) were computed for the SMRs obtained in the Kodak study and compared with predicted CIs derived from applying the multistagecarcinogenesis model to the mouse bioassay data. Adjusting for the healthy worker effect decreased the number of expected deaths from lung and liver cancerin the Kodak study; however, none of the SMRs exceeded unity. The CIs of the SMRs predicted by applying the multistage carcinogenesis model to the mouse datawere clearly nested within those obtained in the Kodak study. The authors conclude that the negative results obtained in the Kodak study are not inconsistent with predictions from the mouse bioassay data after adjusting for differences in study protocol, the healthy worker effects, and statistical variability.

Abstract  The ability of a specific method from the Manual of Analytical Methods of NIOSH to determine chlorodifluoromethane (75456) in workplace air was studied. The method under study was Method 1020, which was recommended by OSHA for this determination. As Method 1020 was developed originally for detection of a liquid, and the current recommendation was to use the method for determination of a gas, this proposed use was tested by NIOSH. The tests indicated that the capacity of the 100/50 milligram (mg) charcoal sorbent bed was limited, the standard preparation procedure was incorrect for a gas analyte, and the analyte had low solubility in carbon-disulfide. Method 1018 for dichlorodifluoromethane (75718) used two coconut shell charcoal tubes in series, a 400/200mg tube followed by a 100/50mg tube, desorbed with methylene-chloride. Test atmospheres for 0.5 to two times the permissible exposure limit for chlorodifluoromethane were generated for the study. Changes were made in the standard preparation procedure and the gas chromatograph was equipped with a capillary column to make the method more suitable for this purpose. By making these revisions to the method, a 96.5% recovery was obtained along with a total precision for the method of 7.1% for chlorodifluoromethane. The method presented no significant bias. The authors conclude that the revised Method 1018 is suitable for determining chlorodifluoromethane in workplace air.

Abstract  Various protonic zeolites (H-Y, H-ZSM-5, and H-MOR) were tested for the total combustion of dichloromethane (DCM) as a model reaction for the catalytic destruction of chlorinated organic pollutants. The order of catalytic activity decreased in the following order: H-MOR > H-ZSM-5 > H-Y Strong Bronsted acidity played a determining role in controlling the active catalytic behavior as revealed by TPD of ammonia and IR measurements of adsorbed pyridine. DCM oxidative decomposition gave rise to CO and HCl as main products along with small amounts of CO2 and Cl-2. In addition, methyl chloride was detected as a reaction intermediate between 250 and 500degreesC The presence of water in the feed stream led to an inhibition of the zeolite activity and resulted in a noticeable change in the reaction product distribution. Water effectively promoted the selectivity toward environmentally desirable reaction products, that is, HCl and CO2, and completely suppressed the formation of methyl chloride.

Abstract  A detailed investigation was conducted into the concentration of polycyclic aromatic hydrocarbons (PAHs) associated with PM10 particles collected during 2012 in an urban area in Cordoba, Argentina. Their composition was studied and the lifetime lung cancer risk resulting from exposure to total and individual PAHs was estimated. Samples of PM10 were collected daily on fiber glass filters with PAHs being extracted with methylene chloride and analyzed by HPLC. Mean PAH concentrations were higher during autumn and winter. In contrast, during warm months, high ambient temperature and wind speed contributed to a decrease in the PAH ambient concentrations. The PAH levels found in the present study were within the range of those reported in other polluted urban areas. However risk factors calculated for exposure to individual and cumulative PAHs exceeded the carcinogenic benchmark level of 1 × 10(-6) early in childhood, implying that these PAH concentrations represent a serious risk to public health.

Abstract  Poly(ortho ester) (POE) nanoparticles were prepared by two different emulsification techniques: novel double emulsion solvent diffusion (DESD) and double emulsion solvent evaporation (DESE). We investigated the effect of sonication time/speed, type of organic phase solvents, polymer concentration, organic/aqueous phase ratio, surfactant type and concentration on the mean particle sizes of obtained POE nanoparticles by both DESD and DESE methods. Different organic solvents [ethyl acetate, methyl ethyl ketone, acetone, dichloromethane and chloroform] were used with several stabilizers [pluronic F 68, didodecyl dimethyl ammonium bromide, poly(vinyl alcohol), and sodium dodecyl sulfate]. The particle size of nanoparticles was observed by the dynamic light scattering method and transmission electron microscopy. We assumed that combining the double emulsion system with a partially water-soluble organic solvent, ethyl acetate, would result in better encapsulation efficiency of water-soluble drugs in nanoparticles and the utilization of both biocompatible surfactants and solvents. As a model drug, we used vancomycin hydrochloride, a hydrophilic low molecular weight glycopeptide antibiotic. The new nanoparticle preparation technique, DESD, resulted in improved formulation characteristics including smaller size, lower size distribution, higher encapsulation yield, and more biocompatible ingredients with unaltered bioactivity of vancomycin hydrochloride in comparison to classical DESE method used to load hydrophilic molecules. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  Modified Ball clay (MBC) and chitosan composite (MBC-CH) was prepared and its application for methylene blue (MB) adsorption from aqueous solution in an industrial prototype fixed-bed column adsorption was investigated. Morphological structure and functional groups of the MBC-CH were determined by scanning electron spectroscopy and Fourier transform infrared spectroscopy analysis, respectively. Batch adsorption studies revealed that MB adsorption on MBC-CH increased with increase in initial concentration and solution pH 4-12. Study on effect of some inorganic salts on MB adsorption revealed that sodium sulphate anions (SO42-) had greater inhibition effect than those of sodium chloride and sodium bicarbonate on both MBC and MBC-CH. The effects of initial concentration (30-300 mg/L), adsorbent bed height (2.5-4.5 cm) and influent flow rate (5-10 mL/min) on fixed-bed column adsorption breakthrough curves were evaluated. Column sorption capacities were 70 mg/g for MBC and 142 mg/g for MBC-CH. Dynamic modeling analysis revealed that Bohart-Adams model can best be used to predict the effluent breakthrough curves for successful design of MB adsorption than Yoon-Nelson model. Adsorption system failure studies showed that the adsorbents were resilient with some improvement observed at time of exhaustion and increased volume of effluent treated. The MBC-CH had above 50% adsorption uptake capacity after five regeneration cycles, this was higher than MBC. Adsorption of MB on MBC-CH was spontaneous, endothermic and had great affinity between the adsorbate and adsorbent. The findings of this study revealed that MBC-CH is a potential adsorbent for cationic dye pollution remediation. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  Comprehensive two-dimensional gas chromatography (GC × GC) utilizing a flow modulator was applied to study particulate polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in the urban atmosphere. Samples were collected onto quartz fiber filters using a PM2.5 sampler at Megacity Shanghai, China. Sample preparation included extraction into n-hexane-dichloromethane mixture and cleanup on silver-impregnated silica column. Analyses were performed well with GC × GC-FID and GC × GC-TOFMS equipment. Average particulate PAHs and n-alkane concentrations were in the range of 40-100 ng/m(3) and 120-500 pg/m(3), respectively. It is alarming to note that PAHs and n-alkane concentrations were increasing with urban PM2.5 values and exceeded the air quality standards in many sampling events. Among them, 2-ring, 3-ring, and 4-ring PAHs accounted for the majority of total PAHs, and C10-15 accounted for the majority of particulate n-alkanes. Potential sources of PAHs in PM2.5 were identified using the diagnostic ratios between PAHs. Local emission sources such as combustion from gasoline and diesel engines were the main contributors of particulate-associated PAHs, while long-range transport had minor contribution to the particulate PAHs. Additionally, we determined the overall carcinogenicity of the samples based on PAH concentrations by a dose addition model and found that the overall carcinogenicity during polluted period was obviously higher than during good air quality period.

Abstract  A full analytical procedure involving extraction and clean-up is presented for the determination of the tri-, tetra-, penta- and hexa-chlorobenzenes in sediments. For this study, the gas chromatography coupled to electronic capture detection was used.

The samples were dried with sodium sulphate and Soxhlet extracted for 16 hours with dichloromethane. Then this solvent was replaced by hexane and the resulting solution was concentrated in a rotary evaporator The clean-up process consisted of elution through a mixed silica column followed by a treatment with activated copper turnings to remove the sulphur The sample was then concentrated down to 2 mL by nitrogen stream. The internal standard, 1,4-dibromobenzene, was added to the sample prior to the extraction, whereas the injection standard, 1,3,5-tribromobenzene, was added right before the sample was injected through the chromatographic system.

The limits of quantification ranged from 71 to 500pg g(-1) (dry weight). The reproducibility in the peak areas within a day was better for the compounds with increasing number of chlorines, whereas the reproducibility over time studies provided no significant differences in the peak areas in consecutive days.

The method was successfully applied to the determination of polychlorobenzenes in a certified sediment and, finally, it was applied to the determination of these compounds in several sections of a sediment core from Esthwaite Water Lake (United Kingdom).

Abstract  Nanocrystalline titanium oxide (TiO(2)) is a promising material as a photocatalyst for photodecomposition of hazardous organic pollutants under illumination, because it is cheap, safe, environmentally benign, and chemically stable. However, the control of particle size and monodispersity of TiO(2) is a challenging task. The use of MCM-41, an inorganic template of uniform pore size (2-10 nm), can overcome this difficulty and produce stable nanoparticles of uniform size and shape. In an attempt to extend light absorption of the TiO(2)-based photocatalyst towards the visible light range and eliminate the rapid recombination of excited electrons/holes during photoreaction, a new photocatalyst (25%TiO(2)-loaded W-MCM-41) powder was prepared. W-MCM-41, with different ratios of Si to W (Si/W = 25, 50, 75), was synthesized by a hydrothermal method and loaded with 25 wt% TiO(2) utilizing a sol-gel method. In order to compare the photocatalytic activity of our sample, titania-loaded plain MCM-41 was also prepared. These materials were characterized by various physiochemical techniques such as UV-visible absorption spectroscopy, x-ray diffraction, nitrogen adsorption-desorption isotherm measurement, Fourier transform infrared (FT-IR) spectroscopy, and transmission electron microscopy. The photocatalytic activity of the prepared samples was evaluated using methyl orange as a model organic compound. It was found that the photodegradation ability of 25% TiO(2)-loaded W-MCM-41 was highly related to the amount of W atoms present in the sample; the optimum atomic ratio of Si to W was 25. It has been confirmed that the recombination rate of electrons/holes in 25%TiO(2)/W-MCM-41 declined due to the existence of W atoms in the sample.

Abstract  We searched MEDLINE and EMBASE for epidemiologic studies on occupational exposure to methylene chloride and risk of cancer. Estimates of study-specific odds ratios (ORs) were calculated using inverse-variance-weighted fixed-effects models and random-effects models. Statistical tests for heterogeneity were applied.

We summarized data from five cohort studies and 13 case-control studies. The pooled OR for multiple myeloma was (OR 2.04; 95 % CI 1.31-3.17) in relation to occupational exposure to methylene chloride but not for non-Hodgkin's lymphoma, leukemia, breast, bronchus, trachea and lung, brain and other CNS, biliary passages and liver, prostate, pancreas, and rectum. Furthermore, we focused on specific outcomes for non-Hodgkin's lymphoma and multiple myeloma because of exposure misclassification. The pooling OR for non-Hodgkin's lymphoma and multiple myeloma was 1.42 (95 % CI 1.10-1.83) with moderate degree of heterogeneity among the studies (I (2) = 26.9 %, p = 0.205).

We found an excess risk of multiple myeloma. The non-Hodgkin's lymphoma and leukemia that have shown weak effects should be investigated further.

Abstract  As part of a study examining the possible effects of organochlorine compounds on juvenile northern elephant seals (Mirounga angustirostris), blubber and blood samples were taken from animals present on the Ario Nuevo (California) rookery, and from animals admitted for rehabilitation at The Marine Mammal Center (Sausalito, CA). Blubber samples were collected from immobilized seals. A pre-cleaned 6mm K-medic biopsy punch was used to extract the blubber from a 1 cm incision near the hip, near the dorsal mid point. Blood samples were taken from the extradural vein; two mL of serum was analyzed for organochlorine compounds. Blubber samples (approximately 0.1g) were ground with Na2SO4 and extracted with 20 mL hexane:methylene chloride (1:1). Sera samples were extracted using commercial available disposable C18 columns. The extracts were separate on a micro-Florisil column, and analyzed by HRGC-ECD. Lipid determination in the serum was obtained colorimetric analysis with 20 mu

Abstract  The stability of liquid jet of dichloromethane in dense carbon dioxide was investigated in an aerosol solvent extraction system (ASES). The stability experiments were carried out at pressures ranging 30-150 bar and a temperature of 308 K, with a nozzle size diameter of 0.254 mm. Interfacial tensions of dichloromethane-carbon dioxide system were measured using a capillary rise method to correlate the stability of liquid jets with a dimensionless number. A new dimensionless number, Z*, was proposed to define an atomization flow regime of the liquid jets in dense carbon dioxide. (C) 2008 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. A Number 1 fuel heating oil was studied for the organo-nitrogen content. The organo-nitrogen compounds were isolated by mild acid extraction followed by silica gel adsorption. Three extracts were studied - a basic nitrogen extract in methylene chloride, a nonbasic nitrogen extract in methylene chloride. The major constituents of each extract were identified by GC. There were seven major classes of nitrogen compounds detected in each extract. These compounds included alkyl-substituted carbazole, indole, pyrazine, pyridine, pyrroles, quinolines and tetrahydroquinolines. The nitrogen content and disturbution was compared to both tar-sands and shale derived fuels./POISONING

Abstract  Recent studies have focused on enantiomeric behaviors of chiral organochlorine pesticides (OCPs) in biotic matrix because they provide insights into the biotransformation processes of chiral OCPs. In the present paper, a double in-line column chromatographic method was developed to effectively remove the lipid impurity in different biotic samples for clean-up of OCPs. After an initial Soxhlet extraction of OCPs from the biotic samples by a mixture of acetone and dichloromethane (DCM), dimethyl sulfoxide (DMSO) was directly added to the extract, and low boiling point solvents (acetone and DCM) were then evaporated. OCPs remained in DMSO were eluted via column 1 filled with silicon gel, and subsequently passed through column 2 packed with 15% deactivated florisil. This novel method was characterized by significant time and solvent savings. The recovery rates of alpha-HCH (hexachlorocyclohexane), beta-HCH, gamma-HCH and delta-HCH were 78.5+/-3.1%, 72.4+/-7.7%, 72+/-4.0% and 70.0+/-8.7%, respectively, and 92.5+/-3.8%, 79.7+/-6.7% and 83.4+/-6.5% for 1,1-dichloro-2-(2-chlorophenyl)-2-(4- chlorophenyl) ethylene (o,p'-DDE), 1,1-dichloro-2-(2-chlorophenyl)-2-(4-chloro phenyl)ethane (o,p'-DDD) and 1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl) ethane (o,p'-DDT), separately. In addition, the separation efficiencies of the target compounds by both achiral and chiral gas chromatographic columns were satisfactory using the established method. Therefore, the double in-line column chromatography was a useful alternative method for pretreatment of OCPs in different biotic samples.