Due to the onset of urbanization worldwide, there is an increasing demand for improving the quality of the urban environment. Odor in wastewater collection systems (WCSs) can interfere with the comfortable and safe living conditions of citizens. Additionally, it can cause economic losses, such as the corrosion of wastewater collection facilities. In this paper, the mechanism of odor generation in WCSs was summarized, and the odor concentrations and sulfide generation rates measured in domestic and foreign WCSs were comprehensively analyzed to review the characteristics of odor emission in WCSs. The complex odor intensity (dilution-tothreshold value) measured in combined domestic sewers ranged from 10 to 10,000, with a median of 100. The odorous compound with the highest contribution to complex odor intensity was hydrogen sulfide, which was the odor most frequently detected at the highest concentrations in most WCSs (its median and mean concentrations were 378.0 ppb and 3,771.2 ppb, respectively). The odor emission properties in the WCSs in Australia and Finland were similar to those of South Korea, with the median and mean concentrations of hydrogen sulfide being 1,927.5 ppb and 12,306.1 ppb, respectively. The sulfide generation rates measured in domestic and foreign WCSs ranged from 0.003 to 0.220 g m–2 h–1. In addition, the key factors affecting sulfide generation were sulfate and organic matter concentrations, pH, temperature, flow rate (retention time), dissolved oxygen concentration, and electron acceptor concentrations other than sulfate. To control odor in WCSs, various methods have been proposed to improve their anaerobic environment. These include sucking outside air into the WCSs and improving their hydraulic conditions, such as changing the slope of sewer pipes to minimize sediment deposition. Additionally, periodically removing sediments, which contain a significant amount of organic matters and sulfate-reducing bacteria, is also a useful method for controlling odor in WCSs. Since the odor compounds that contribute the highest odor intensity–and are the most frequently detected–are sulfur-containing odors such as hydrogen sulfide, the control of sulfides is crucial for controlling odor in WCSs. There are chemical control methods for the mitigation of sulfide in WCSs, including air (oxygen) injection and introducing various chemicals, such as alkalis, nitrates, iron salts, and biocides. However, most of the results of odor control using these methods were from laboratory-scale studies. Therefore, additional field-scale experiments should be conducted in WCSs to evaluate the actual effectiveness of various odor control methods. Through these field studies, the optimal conditions for each method to control odor in WCSs can be derived, and the efficiency and economic feasibility of each method can be verified.

In the decommissioning process of nuclear power plants, Ni-59, Ni-63 and Fe-55 present in radioactive waste are crucial radionuclides used as fundamental indicators in determining waste treatment methods. However, due to their low-energy emissions, the chemical separation of these two radionuclides is essential compared to others. Therefore, this study aims to evaluate the suitability of various pre-treatment methods for decommissioning waste materials by conducting characteristic assessments at each chemical separation stage. The goal is to find the most optimized pre-treatment method for the analysis of Ni-59, Ni-63 and Fe-55 in decommissioning waste. The comparative evaluation results confirm that the chemical separation procedures for Fe and Ni are very stable in terms of stepwise recovery rates and the removal of interfering radionuclides. However, decommissioning waste materials, which mainly consist of concrete, metals, etc., possess unique properties, and a significant portion may be low-radioactivity waste suitable for on-site disposal. Considering that the chemical behavior and reaction characteristics may vary at each chemical separation stage depending on the matrix properties of the materials, it is considered necessary to apply cascading chemical separation or develop and apply individual chemical separation methods. This should be done by verifying and validating their effectiveness on actual decommissioning waste materials.

Measurement of oxide ion (O2-) concentration is a basic technology required in molten salt fields, from energy storage systems to electrolytic reduction of rare earth elements or spent nuclear fuels. In a molten salt reactor, O2- ions react with actinide elements to form their oxides or oxy-chlorides to induce actinide precipitation, and promote metal corrosion to cause a failure of structural material. For these reasons, removal of O2- ions and monitoring of the O2- concentration in molten salt reactors are essential. In this study, methods using chemical and electrochemical methods were investigated for measuring the concentration of O2- ions in a molten salts. The acid-base neutralization reaction was used as a chemical analysis method. And electrochemical methods using the O2- diffusion limit current and YSZ (yttria stabilized zirconia) indicator electrode were used for measuring the O2- concentration. Finally, a modified method using porous membrane electrode was applied to monitor the O2- concentration. The O2- concentration was measured up to about 2wt% of Li2O by the method using the O2- diffusion current, up to about 4wt% by the YSZ indicator electrode, and about 6wt% by the porous membrane electrode in LiCl molten salts.

PURPOSES : In this study, the alkali aggregate reactivity and expansion characteristics of mortar mixed with waste glass (a recycled aggregate) were confirmed to verify the alkali-silica reaction (ASR) stability and review the appropriateness of the alkali aggregate reactivity test method following the replacement of recycled aggregate. METHODS : The alkali-aggregate reactivity of waste glass aggregates was measured using the chemical and physical methods described in KS F 2545 and ASTM C 1260, respectively. The reactivity was classified by comparing the results. Cement with a high-alkali content was used to simulate an environment that can induce ASR. Non-reactive fine aggregates, waste glass fine aggregates, reactive general aggregates, and Ferronickel slag aggregates were used as control groups. RESULTS : Waste glass fine aggregates were classified as reactive when applying the chemical method. In the physical method, they were classified as reactive at 100% and latent reactive at 1%, based on the mixing ratio. Additionally, we discovered that the reliability of the chemical method was low since the ASR of the aggregates was classified differently based on the evaluation method, while the results of the chemical and physical test methods were inconsistent. CONCLUSIONS : To determine the alkali reactivity of recycled aggregates, the complex use of chemical and physical methods and analysis based on the mixing ratio of the reactive aggregates are required. Small amounts of waste glass aggregate replacements affected the ASR. Because ASR reaction products can affect the long-term thermal expansion of the structure, further research is needed to use ASR aggregates in structures.

The purpose of the study is to analyze the physical and chemical characteristics of soils from the forest fire burned area in Gyeongju National Park. According to the physical characteristics of soils, soil temperatures and soil moistures in reforestation area (site 2 and 3) and natural restoration area (site 4 and 5) were higher than in control area (site 1). In terms of chemical characteristics, hydrogen exponents (pH) in reforestation area and natural restoration area were higher than in control area. The rates of available phosphoric acid (P2O5) in control area and reforestation area (site 1) had high rates, but rates in reforestation area (site 2) and in natural restoration area (site 5) had low rates. The rates of accumulated organic matter (O. M.) in reforestation area and natural restoration area were lower than in control area. The percentages of total nitrogen (T. N.) were analyzed similarly in all study areas and soils from reforestation area and natural restoration area had higher cation exchange capacity (CEC) than from control area. Therefore these results determines that soils from the forest fire burned area are being restored to normal gradually.

Graphene oxide powders prepared by two different drying processes, freeze drying and spray drying, were studied to compare the effect of the drying method on the physical properties of graphene oxide powder. The graphene oxide dispersion was prepared from graphite by chemical delamination with the aid of sulfuric acid and permanganic acid, and the dispersion was further washed and re-dispersed in a mixed solvent of water and isopropyl alcohol. A freeze drying method can feasibly minimize damage to the sample, but it requires a long process time. In contrast, spray drying is able to remove a solvent in a relatively short time, though this process requires exposure to a high temperature for a rapid evaporation of the solvent. The powders prepared by freeze drying and spray drying were characterized and compared by Raman spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and by an elemental analysis. The graphene oxide powders showed similar chemical compositions; however, the morphologies of the powders differed in that the graphene oxide prepared by spray drying had a winkled morphology and a higher apparent density compared to the powder prepared by freeze drying. The graphene oxide powders were reduced at 900˚C in an atmosphere of N2. The effect of the drying process on the properties of the reduced graphene oxide was examined by SEM, TEM and Raman spectroscopy.

The purpose of this study is the fabrication of nano-sized Fe-Co alloy powders with soft magnetic properties by the slurry mixing and hydrogen reduction (SMHR) process. 0 and powders with 99.9% purities were used for synthesizing nanostructured Fe-Co alloy powder. Nano-sized Fe-Co alloy powders were successfully fabricated using SMHR, which was performed at 50 for 1 h in H atmosphere. The fabricated Fe-Co alloy powders showed ' phase (ordered body centered cubic) with the average particle size of 45 nm. The SMHR powder exhibited low coercivity force of 32.5 Oe and saturation magnetization of 214 emu/g.

Fe-Co nanocomposite powders with different composition were prepared by chemical vapor condensation (CVC) process and their characterizations were studied by means of X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The particles having the mean size of 5~25 nm consisted of metallic cores and oxide shells. The Co contents and particle size increased with increasing the carrier gas flow rate of Co precursor. The saturation magnetization and coercivity increased with increasing Co content. and the saturation magnetization maximized at the 40 wt.%Co. The Fe-Co nanocomposite powder oxidized at showed the maximum coercivity of 1739 Oe.

Chemical properties of the different parts of watercress(Oenanthe javanica D.C.) grown and harvested from the culture fields under different cultivating methods were studied. In proximate analyses of watercress in parts, moisture contained more in stem than in root or in leaf, but crude protein and crude lipid contents were lower in stem than in root or in leaf. Crude ash in root contained up to about double amount in leaf or stem. Major mineral elements detected in watercress were Fe, Mg, Ca, and K, and their contents in root was higher than those in stem or leaf. Especially, Fe in root was significantly higher than that in stem or in leaf. Total free sugar composed mainly with fructose and glucose, was the highest in watercress from Hwasoon and followed the watercress from Jeonju and Donggok in order. Free sugar content was highest in leaf and the lowest in root. Major water-soluble vitamins were vitamin C, thiamin and biotin and the content of vitamin C was higher than others. These vitamins contained more in leaf than in stem or root. Niacin contained 6.09 mg/100 g in leaf of watercress from Hwasoon, which was much higher than others, but it was not detected in stem of watercress from Jeonju. Organic acids detected were oxalic acid, citric acid and malic acid and other 12 organic acids were not detected. In fatty acid composition, there were significant differences among watercresses from different parts and different culture fields. Linoleic acid, linolenic acid and palmitic acid were major fatty acids contained in watercress and it took about 80% of the total content. Amino acid content in leaf was higher than that in root and in stem. Glutamic acid and proline were major amino acids in stem of watercress from Jeonju and in stem of watercresses from Hwasoon and Donggok, respectively. In leaves of all three watercresses glutamic acid content was the highest.

15종의 채소류를 생채, 데침, 찜, 끓임, 볶음 조림할 때 Vit.A, Niacin, AsA 및 P, Fe, Mg, Ca, Na, K의 잔존량을 측정한 결과는 다음과 같았다. 1. 생채에서 Vit.A는 도라지, 상추, 오이의 잔존량이 높은 반면 무는 50%로 가장 낮았고 Niacin과 AsA는 전반적으로 잔존율이 높았으며 무, 상추, 돌나물, 오이, 들깻잎에서는 증가된 것으로 나타났다. 무기질에서는 P은 도라지, 양배추, 상추에서, Fe은 도라지, 양배추, 돌나물에서, Mg과 Ca은 도라지, 상추, 돌나물에서 K은 양배추와 상추에서 잔존율이 높았다. 2. 데침시에 Vit.A는 콩나물, 숙주에서, Niacin는 콩나물, 숙주, 들깻잎에서 잔존율이 높았으나 AsA는 다른 비타민에 비하여 잔존율이 크게 떨어졌다. 무기질은 P은 참취, 콩나물, 숙주에서, Fe은 참취, 숙주, 시금치에서, Mg은 들깻잎에서, Ca은 시금치, 들깻잎에서, Na은 시금치에서, K은 무, 들깻잎에서 잔존율이 높은 편이었다. 3. 찜에서 Vit.A는 양배추에서, Niacin은 가지, 양배추, 들깻잎, 오이에서, AsA는 무, 양배추, 오이에서 잔존율이 높았으며 잔존율이 아주 낮은 것은 Vit.A에서의 무와 들깻잎, AsA는 들깻잎이었다. 무기질 중 P은 양배추, 오이, 들깻잎에서, Ca은 양배추, 오이, 무에서, Na은 무, 오이, 양배추에서, K은 들깻잎, 양배추에서 잔존율이 높았다. 한편, 무기질의 잔존율이 아주 낮은 것은 Fe은 호박, 가지에서, Mg은 호박에서, Ca과 Na은 들깻잎에서, K은 가지이었다. 4. 끓임시에 Vit.A는 콩나물, 숙주에서 Niacin은 콩나물, 참취, 숙주에서 잔존율이 높은 반면 AsA는 대체로 50%이하의 낮은 잔존율을 보였다. 극히 저조한 잔존율을 보인 것은 Vit.A의 무, 호박, 참취, 시금치, AsA의 시금치, 호박, 참취, 숙주이었다. 무기질에서 P은 숙주, 호박, 참취에서, Fe은 시금치, 무, 숙주에서, Mg은 참취, 무에서 Ca은 호박, 시금치에서 잔존율이 높았고 Na와 K은 이들에 비해 잔존율이 낮은 편이었다. 그중, 극히 낮은 잔존율을 보인 것은 Fe에서 콩나물, 호박, Mg에서 시금치, 콩나물, 숙주, Na에서 콩나물, K에서 콩나물, 시금치이었다. 5. 볶음시에 Vit.A는 도라지, 당근, 시금치에서 Niacin은 도라지에서 AsA는 가지에서 잔존율이 높은 편이나, 무, 참취에서는 Niacin이 무, 참취, 도라지에서는 AsA의 잔존율이 아주 낮았다. P은 호박, 참취, 도라지, 당근에서 Fe은 참취, 도라지에서 Mg은 참취, 도라지, 당근, 호박에서 Ca과 Na은 도라지, 당근, 오이에서 K은 호박, 참취, 도라지, 당근에서 잔존율이 아주 낮았으며 가지는 모든 무기질의 잔존율이 아주 낮았으며 그 외 호박에서는 Fe이, 돌나물에서는 K이 극히 낮은 잔존율을 보였다. 조림시에는 Vit.A는 우엉에서, Niacin은 무, 우엉 모두 잔존율이 높은 반면 AsA는 둘다 낮은 편이었다. 무기질은 무에서 Fe, Ca, Na, K과 우엉에서는 Na, P, K의 잔존량이 높은 반면 우엉에서 Fe의 잔존율이 극히 낮았다. 6. 각종 조리시 비타민과 무기질의 잔존상태가 전체적으로 좋은 결과를 보인 채소의 순서는 사용된 횟수에 차이가 있으나 도라지>들깻잎, 양배추>무, 오이>참취, 상추>숙주>시금치, 우엉, 돌나물>당근, 호박>콩나물>가지로 나타났으며, 조리법 중에서 잔존율이 좋은 것은 비타민의 경우는 생채이었고 무기질은 생채, 볶음, 조림이었다. 또한 Vit.A는 생채, 볶음, 조림에서 Niacin은 생채, 조림, 찜에서 AsA는 생채에서 잔존율이 좋았으며 P은 볶음, 생채에서, Fe은 생채, 데침, 끓임, 조림, 볶음에서 Mg은 생채, 조림, 볶음에서 Ca은 생채, 찜, 끓임, 조림, 볶음에서 Na은 조림, 볶음에서 K은 생채, 조림, 볶음에서 잔존율이 좋은 편이었다.

현재(現在) 우리나라에서 재배(栽培)되고 있는 국화(菊花) 8품종(品種)을 공시(供試)하여 국화(菊花)잎선충에 대(對)한 저항성조사(抵抗性調査), 피해엽율(被害葉率)과 강우(降雨)와의 관계(關係), 그리고 관수방법(灌水方法)이 피해엽율(被害葉率)에 미치는 영향(影響)을 조사(調査)하고 몇가지 살충제의 방제효과(防除效果)에 관(關)하여 실험(實驗)한 결과(結果), l. 국화(菊花)잎선충(Aphelenchoides ritzemabosi)에 대(對)한 국화품종(菊花品種)의 저항성(抵抗性) 검정(檢定)에서 Shuhonothikara는 11.7%, Sagakiku는 14.5%로서 저항성(抵抗性)을 나타내었고 Sinrokusiogio, Dangonanako, Sintoa 등(等)은 50% 이상(以上)의 피해엽율(被害葉率)로 감수성(感受性)을 나타냈으며 Gold wave, Tenju 등(等)은 24~26%로 중간정도(中間程度)를 나타냈다. 2. 피해엽율(被害葉率)과 엽면적(葉面積), 엽후(葉厚), 기공수(氣孔數), 기공(氣孔)의 크기 및 모즙장(毛葺長) 등(等)과는 상관(相關)이 없었고 모즙수(毛葺數)와는 정(正)의 상관(相關)을 나타냈다. 3. 관수방법(灌水方法)에 따른 피해엽율(被害葉率)은 P. E. film에 의(依)한 강우(降雨)를 차단(遮斷)하고 지면관수(地面灌水)한 구(區)에서 9.4%로 가장 낮았으며, 자연상태(自然狀態)에서 지면관수(地面灌水)한 구(區)가 50%로 다음이었고 자연상태(自然狀態)에서 Spray한 구(區)가 62.4%로 가장 높게 나타났다. 4. 피해엽율(被害葉率)과 강우(降雨)와의 관계(關係)는 강우량(降雨量)보다는 강우일수(降雨日數)가 밀접(密接)한 관계(關係)를 내타내었다. 5. 살선충제의 토양처리(土壤處理)에 의(依)한 방제효과(防除效果)는 무처리구(無處理區)에 비(比)해 현저한 방제효과(防除效果)를 보여 주었으며 약제별(藥劑別)로는 Temik이 평균피해엽율(平均被害葉率)이 5%로 가장 낮게 나타났으며 무처리(無處理)나 타약제(他藥劑)에 비(比)하여 현저한 유의차(有意差)를 나타내었고 Carbofuran, Otran, Mocap 등(等) 약제간(藥劑間)에는 유의성(有意性)은 인정(認定)되지 않았으나 무처리(無處理)에 비(比)하여는 고도(高度)의 유의차(有意差)를 나타내었다.

본 시험은 Omethoate (Folimat) 외 6종의 침투성 살충제를 공시하여 수간주입에 의한 솔잎혹파리의 방제효과를 검토하는 한편 관행 Drilltlr 수간주입방법을 보다 성력적인 방향으로 개량코자 실시하여 다음과 같은 결과를 얻었다. 1. Phosalone을 제외한 Omethoate , Vamidothion (Kilval 40 EC), Methamidophos , Phosphamidon , Monocrotophos 및 Dimethoate 의 수간주입은 솔잎혹파리의 방제효과가 비교적 우수하였다. 2. 관행 Drill 식 수간주입과 개량 Mauget식 수간주입간에는 그 효과발현에 차이가 없었다. 3. 관행 Drill식 수간주입에서 주입공의 상처회복율은 인데 비하여 개량 Mauget식 수간주입에서는 완전 회복되었다. 이상의 결과를 종합하여 볼 때 개량 Mauget식을 도입하므로서 보다 성력적인 수간주입에 의한 솔잎혹파리의 방제가 가능하다고 본다.

This study was performed to analysis of chemical constituent in Polygonum multiflorum root (PMR) by different dry methods (hot-air dry, shade dry, and freeze dry). The results are summarized as followings; major free sugar were detected fructose, glucose, and sucrose in dried PMR based on various dry methods. The highest content of free sugars was found in freeze dried PMR. The four organic acids were detected in dried PMR by HPLC analysis. The content of oxalic acid in shade dried PMR was higher than the dried PMR by different dry methods. The content of total amino acid and essential amino acids were high in the orders of freeze drying > shade drying > hot-air drying. The potassium and magnesium levels of freeze dried PMR was significantly higher than the other drying method of PMR. Whereas the calcium and sodium levels were higher in hot-air dried PMR. The major fatty acids were determined the linoleic acid in PMR by different dry methods.

This study was conducted to investigate the quality properties depending on the cultivation methods (general, organic, pesticide-free) of yuza and its various parts (peel, pulp, seed). The contents of hesperidin were the highest in yuza feel grown by pesticide-free method (13.23 mg/g). The contents of naringin presented a higher content in the peel, especially which of the general (4.62 mg/g) showed the highest value. Vitamin C analysis showed the highest content in the peel, significantly varied according to the cultivation method and various parts (p<0.05). Vitamin C value was significantly highest in organic peel, which was 770.02 mg/100 g, whereas among the peel, the pulp and the seed were it the lowest in the seed. The content of total polyphenols were the highest in general peel (0.85 mg/g). Flavonoid content of pesticide-free seed was significantly higher than those of the other yuja samples which was 0.89 mg/g (p<0.05). The DPPH radical scavenging activity was relatively more active in the peel among the above-mentioned three parts, especially the pesticide-free peel was most active, which was 73.94%. The ABTS radical scavenging activity of organic peel was significantly active among the samples, which was 84.47% (p<0.05). Based on these results, it can be said that yuja has variety of useful components in the pulp and the seed as well as the peel: and thus it’s hight recommended to develop more varied yuja products.

화학 산업에서의 안전규제는 중대사고의 교훈과 안전규제에 대한 중요성을 인식하기 시작하면서 발전하였다. 본 연구에서는 세베소 2 지치에서부터 본격적으로 논의된 화학사고 관리시스템에 대해서 조사하였고, 국내에서 적용 가능한 화학물질 사고 정보 관리 시스템을 제안하였다. 이 시스템을 기반으로 1990년부터 2009년까지 국내에서 발생한 화학물질 사고를 환경부의 유해화학물질 관리법에서 관리하고 있는 사고대비물질 69종과 유독물 588종에 대해서 사고사례를 분석하였다. 이러한 화학물질 사고정보 통합 시스템은 지난 수십 년간 중대 화학사고로 인해 전 세계적으로 개정된 관계법령, 안전관리체제와 설비대책 등에 대한 조사와 이를 바탕으로 한 국내 제도개선 등에 활용을 통해 21세기를 향한 안전한국으로서의 기반을 마련할 수 있을 것으로 기대된다.