• Food Science of Animal Resources
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• v.34 no.4
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• pp.525-532
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• 2014

This study was designed to elucidate the effect of ozone exposure on the bacteria counts and oxidative properties of ground Hanwoo beef contaminated with Escherichia coli O157:H7 at refrigeration temperature. Ground beef was inoculated with 7 Log CFU/g of E. coli O157:H7 isolated from domestic pigs and was then subjected to ozone exposure ($10{\times}10^{-6}kg\;O_3h^{-1}$) at $4^{\circ}C$ for 3 d. E. coli O157:H7, total aerobic and anaerobic bacterial growth and oxidative properties including instrumental color changes, TBARS, catalase (CAT) and glutathione peroxidase (GPx) activity were evaluated. Ozone exposure significantly prohibited (p<0.05) the growths of E. coli O157:H7, total aerobic and anaerobic bacteria in ground beef samples during storage. Ozone exposure reduced (p<0.05) the CIE $a^*$ value of samples over storage time. The CIE $L^*$ and CIE $b^*$ values of the samples fluctuated over storage time, and ozone had no clear effect. Ozone exposure increased the TBARS values during 1 to 3 d of storage (p<0.05). The CAT and GPx enzyme activities were not affected by ozone exposure until 2 and 3 d of storage, respectively. This study provides information about the use of ozone exposure as an antimicrobial agent for meat under refrigerated storage. The results of this study provide a foundation for the further application of ozone exposure by integrating an ozone generator inside a refrigerator. Further studies regarding the ozone concentrations and exposure times are needed.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.122-131
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• 2001

Pakistan being the 6$^{th}$ largest sugar producer has over 75 sugar mills with annual production capacity of about 2.4 million tons during 1996-97. The contribution of Sindh with 27 sugar mills is recorded over 50% of the total sugar production. The majority of the mills in Pakistan use the Defecation-Remelt-Phosphitation (DRP; 24 mills), Defecation-Remelt-Carbonation (DRC; 21 mills) and Defecation-Remelt Carbonation and Sulphitation (DRCS; 11 mills) process. Seven of the 75 sugar mills in Pakistan also produce industrial alcohol from molasses, a by- product of sugar manufacturing process. These sugar industries also produce fly ash, which have been found to contain unburned carbon and reach as far as four-kilo meter area with the wind direction, threatening the community health of people living around, besides posing other aesthetic problems. The untreated wastewater, in many cases, finds its way to open surface drains causing serious threat to livestock, flora and fauna. One study showed that fly ash emitted from the chimneys contain particle size ranging from 38 ${\mu}{\textrm}{m}$ to 1000 ${\mu}{\textrm}{m}$. About 50 per cent of each fly ash samples were above 300 ${\mu}{\textrm}{m}$ in size and were mostly unburned Carbon particles, which produced 85% weight loss on burning in air atmosphere at 1000${\mu}{\textrm}{m}$. This fly ash (mostly carbon) was the main cause of many health and aesthetic problems in the sugar mill vicinity. The environmental challenge for the local sugar mills is associated with liquid waste gaseous emission and solid waste. This paper discusses various waste recycling technologies and practices in sugar industries of Pakistan. The application of EM technology and Biogas technology has proved very successful in reusing the sugar industry wastewater and mud, which otherwise were going waste.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.586-591
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• 2001

This research investigated the feasibility of the accelerated carbonation of cement waste forms with carbon dioxide in a supercritical state. Hydraulic cement has been used as a main solidification matrix for the immobilization of radioactive and/or hazardous wastes. As a result of the hydration reaction for major compounds of portland cement, portlandite (Ca(OH)$_2$) is present in the hydrated cement waste form. The chemical durability of a cement form is expected to increase by converting portlandite to the less soluble calcite (CaCO$_3$). For a faster reaction of portlandite with carbon dioxide, SCCD (supercritical carbon dioxide) rather than gaseous $CO_2$, in ambient pressure is used. The cement forms fabricated with an addition of slated lime or Na-bentonite were cured under ambient conditions for 28days and then treated with SCCD in an autoclave maintained at 34$^{\circ}C$ and 80atm. After SCCD treatment, the physicochemical properties of cement matrices were analyzed to evaluate the effectiveness of accelerated carbonation reaction. Conversion of parts of portlandite to calcite by the carbonation reaction with SCCD was verified by XRD (X-ray diffraction) analysis and the composition of portlandite and calcite was estimated using thermogravimetric (TG) data. After SCCD treatment, tile cement density slightly increased by about 1.5% regardless of the SCCD treatment time. The leaching behavior of cement, tested in accordance with an ISO leach test method at 7$0^{\circ}C$ for over 300 days, showed a proportional relationship to the square root of the leaching time, so the major leaching mechanism of cement matrix was diffusion controlled. The cumulative fraction leached (CFL) of calcium decreased by more than 50% after SCCD treatment. It might be concluded that the enhancement of the characteristics of a cement matrix by an accelerated carbonation reaction with SCCD is possible to some extent.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2547-2552
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• 2010

CdS nano-particulate films were prepared at the air/water interface under Langmuir monolayers of arachidic acid (AA) via interfacial reaction between $Cd^{2+}$ ions in the subphase and $H_2S$ molecules in the gaseous phase. The films were made up of fine CdS nanoparticles with hexagonal Wurtzite crystal structure after reaction. It was revealed that the formation of CdS nano-particulate films depends largely on the experimental conditions. When the films were ripened at room temperature or an increased temperature ($60^{\circ}C$) for one day, numerous holes were appeared due to the dissolution of smaller nanoparticles and the growth of bigger nanoparticles with an improved crystallinity. When the films were ripened further, CdS rodlike nanoparticles with cubic zinc blende crystal structure appeared due to the re-nucleation and growth of CdS nanoparticles at the stacking faults and defect structures of the hexagonal CdS grains. These structures were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and X-ray diffraction (XRD). These results declare that CdS semiconductor nanoparticles formed at the air/water interface change their morphologies and crystal structures during the ripening process due to dissolution and recrystallization of the particles.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2007.11a
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• pp.187-192
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• 2007

A project is being implemented to develop the long distance energy transport technology using the chemical reactions. This project can be classified into three main research categories covering heat recovery reaction, long distance energy transport, and heat generation reaction. In this study, the methanol is selected as a system material since it shows several unique superior characteristics as follows: gaseous state of reactant and product, large heat of reaction, high yields of reaction at relatively low temperature, and also steady and economical supply. Furthermore, it is anticipated that the outcomes of this study can be widely applied to the related industries. A feasibility study was carried out to evaluate the economics of this technology which study was based on the following case: 10,000 households, 15km distance energy transportation, utilization of waste heat from power plant.

• Journal of Plant Biotechnology
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• v.34 no.2
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• pp.81-93
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• 2007

Gas hydrates are known to form by physical interactions between host water and guest gas molecules and thus can be treated as a special type of icy materials. The gas hydrates are recently highlighted because of their use to future energy source even though they were discovered naturally in the deep-sea marine sediments a long time ago. However, the present and future urgent task is to develop the efficient and safe production technology for recovering methane from gas hydrates. Here, we propose one of potential recovery processes using swapping phenomenon occurring between gaseous carbon dioxide and methane hydrate deposits. Such a swapping process provide several technological and economical advantages over conventional processes. The carbon dioxide can be directly sequestered into methane hydrate layer and simultaneously methane can be produced with a high recovery rate more than 90%. In addition, the icy powders can be effectively used as a new medium for storing hydrogen. To increase hydrogen storage capacity the icy hydrate networks need to be redesigned to create the more empty cages in which hydrogen gas can be enclathrated. Functionalized icy materials might be used in a variety of energy and environmental fields.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.60-69
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• 2007

Understanding the behavior of gas phase VOCs (volatile organic compounds) in unsaturated soils is of a great environmental importance for public health concerns. Moment analysis for the breakthrough curves (BTCs) during transport of chemicals in porous media was known to be a useful tool to evaluate the velocity, spreadness, and the skewness of the plume of the chemicals. In this study, the temporal moments of the BTCs of a group of VOCs were analyzed for the gaseous transport in an unsaturated soil. BTCs were measured using lab-scale column experiments for four different VOCs at the water saturation range of 0.04-0.46, and for eleven VOCs at a water saturation of 0.21. The central second and third moments of the VOCs were compared with the water saturation and the first moment. It was found that both central second and third moments increased with the first moment. The central third moment was, however, found to be more sensitive to the first moment.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.42-52
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• 2011

In this laboratory study, the changes in gas-exposed perchloroethene (PCE) saturation in sand during a PCE removal process were measured using gaseous tracers. The flux of fresh air through a glass column packed with PCEcontaminated, partially water-saturated sand drove the removal of PCE from the column. During the removal of PCE, methane, n-pentane, difluoromethane and chloroform were used as the non-reactive, PCE-partitioning, water-partitioning, and PCE and water-partitioning tracers, respectively. N-pentane was used to detect the PCE fraction exposed to the mobile gas. At water saturation of 0.11, only 65% of the PCE was found to be exposed to the mobile gas prior to the removal of PCE, as calculated from the n-pentane retardation factor. More PCE than that detected by n-pentane was depleted from the column due to volatilization through the aqueous phase. However, the ratio of gas-exposed to total PCE decreased on the removal of PCE, implying gas-exposed PCE was preferentially removed by vaporization. These results suggest that the water-insoluble, PCE-partitioning tracer (n-pentane in this study), along with other tracers, can be used to investigate the changes in fluid (including nonaqueous phase liquid) saturation and the removal mechanism during the remediation process.

• Journal of The Korean Dental Society of Anesthesiology
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• v.2 no.1 s.2
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• pp.1-6
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• 2002

The usage of nitrous oxide is increased for the anxious patient to dental treatment. There are two methods to induce the sedation during dental treatment. One is sedation with drugs the other no need of drugs. We discussed here about sedation with drugs. The methods of drug administration are oral, intramuscular, intravenous, inhalation. The method of oral administration of drugs are convenient to patient and doctor but poor controllability. Intramuscular method is a parenteral technique that maintains several advantages over the enteral technique. However its pales in comparison to other parenteral technique. Intravenous method represents most effective method of ensuring predictable and adequate sedation in all patients. But it has inability to reverse the action of drugs after they have been injected except some drugs (e.g., narcotics and benzodiazepine). A variety of gaseous agents may be administered by inhalation to produce sedation. In dental practice, the inhalation administration of gas means use of nitrous oxide. There are many advantages of nitrous oxide administration. First, very short latent period and rapid onset of drug action which lead to possible titration of drug concentration. With nitrous oxide, clinical effects may become noticeable as quickly as 15 to 30 seconds after inhalation. Recovery from inhalation sedation is also quite rapid. In out patient dental practice rapid recovery is very important because it permit to discharge the patient without escort and the patient return to their ordinary life without limit. To success the conscious sedation with nitrous oxide, the administrator should be keep the mind that always titration of nitrous oxide concentration during induction and treatment. Careful observation need during treatment to prevent oversedation because the adequate nitrous oxide concentration to patients changed by environmental stress. Always begins with 100% oxygen and ends with 100% oxygen to prevent diffusion hypoxia which rare in clinical practice.

• Journal of Environmental Health Sciences
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• v.32 no.2 s.89
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• pp.164-170
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• 2006

Ethylene oxide is a genotoxic carcinogen with widespread uses as industrial chemical intermediate and gaseous sterilant. 2-hydroxyethylated N-terminal valine in Hb is a good biomarker for biological monitoring of ethylene oxide exposure, because of its stability. For measuring the hemoglobin adduct formed by exposure of ethylene oxide, we studied the determination of (N-2-hydroxy-ethyl)valine(HEV) in hemoglobin adduct by using GC/MS. Firstly we synthesized HEV with 2-amino-ethanol and bromoisovaleric acid(BIVA) and confirmed it with GC/MS-FID. Its fragmentations were m/z 116(base ion, M+-45) and m/z 130(M+-31). For measuring HEV with higher sensitivity, we use derivatives which were PFPITH(pentafluorophenylisothiocianate) and TBDMS (tributyldimethylsilylation) by using Edman procedure. Its fragmentation were m/z 425(M+-57), m/z 383(M+-99) and m/z 172(M+-310) by using GC/MS. We did biological monitoring for mice inhalation exposure with 400 ppm ethylene oxide. The concentrations of hemoglobin adduct were $168{\pm}3.8\;and\;512{\pm}04$(nmol g-1 globin) at 0.5 hr/day 400 ppm ethylene oxide inhalation exposure group, and $631{\pm}17\;and\;2265{\pm}9.4$(nmol g-1 globin) at 1.0 hr/day 400 ppm ethylene oxide inhalation exposure for 1 and 4 weeks, respectively. We confirmed that (N-2-hydroxy-ethyl)valine(HEV) of hemoglobin was a good biomarker for biomonitoring of ethylene oxide exposure, and can measured with derivatives such as PFPITH(pentafluorophenylisothiocianate) and TBDMS(tributyldimethylsilylation) by using GC/MS.