Fluorine (F) recovery from wet process phosphoric acid (WPA) is essential for sustainable resource utilization and environmental protection. This work systematically investigates the F recovery mechanism by air stripping from three simulated systems: H3PO4- H2SiF6-H2O, H3PO4- HF-H2O, H3PO4- H2SiF6-HF-Al3+-H2O, and from two industrial systems: WPA and WPA-Al3+ under different stripping temperatures (60–110 ℃) and stripping times (0–120 min). The influence on the existence form of F, the content of Al3+ cations and the addition of active silica on the F removal rate in the phosphoric acid solution is studied by analyzing the changes in the contents of F, P and Si. The results indicate that the F in the form of H2SiF6 is more easily released from the phosphoric acid solution than that in the form of HF. While, the release of F is inhibited in the presence of the Al3+ in the solution due to the formation of Al-F complexes that are characterized by 19F NMR, 31Si NMR and FTIR techniques. Interestingly, the addition of active silica can promote the conversion of HF to H2SiF6 in the solution and significantly improve the release rate of F. The researching results can provide an important guidance for industrial practice of WPA.

Mass production of high-quality carbon nanotubes (CNTs) remains a challenge, requiring the development of new wetimpregnated catalyst suitable for the catalytic chemical vapor deposition (CCVD) of CNTs in a fluidized bed reactor. For the successful development of a new catalyst, a highly robust system to synthesize CNTs must be established. Here, we systematically investigated the robustness of CNT synthesis by CCVD using a wet-impregnated catalyst. We statistically tested four factors that could potentially affect the robustness of CNT synthesis system, focusing on carbon yield and IG/ID. First, we tested the effect of vacuum baking before CNT growth. F test and CV equality test concluded that vacuum baking recipe did not significantly reduce the variability of the CNT synthesis. Second, we tested the batch-to-batch variation of catalysts. The results of t test and one-way analysis of variance indicate that there is significant difference in carbon yield and IG/ID among catalysts from different batches. Third, we confirmed that there is spatial non-uniformity of wet-impregnated catalysts within a batch when they are produced in large scale. Finally, we developed a multi-step heating recipe to mitigate the temperature overshooting during the CNT synthesis. The multi-step recipe increased the mean of carbon yield, but did not influence the variability of CNT synthesis. We believe that our research can contribute to the establishment of a robust CNT synthesis system and development of new wet-impregnated catalysts.

The purpose of this study was to evaluate the forage maize varieties and sowing date under wet seasons conditions and determined the effects on yield in Cambodia. In this study, the number of days from sowing to silking was approximately nine longer in May and June than in July, August, and September. The number of days from silking to harvest was seven shorter in May and June than in July, August, and September. The variety with the least decrease in ear height was ‘BT5666’, and the variety with the least decrease in ear height ration was ‘CP888’. On the other hand, in sowing days, ear height ratio decreased in September. The best sowing season in ear length, ear width, number of ears and number of grains per row was in May. In this study, ‘BT5666’ was the variety with significant decrease with a 90% reduction in yield. The results indicate that the yield was high during the sowing period in May and in June because of the appropriate precipitation, temperature, and solar radiation. However, August and September had significantly reduce in yield by high precipitation and low solar radiation.

Graphene-based materials show excellent properties in various applications because of their electrical properties, large surface areas, and high tolerance for chemical modification. The use of wet-process is a promising way for their mass production. Heteroatom doping is one of the common methods to improve their electrical, physical, and electrochemical properties. In this work, we develop a new route for the production B-doped graphene-based materials using low-temperature wet-process, which is the reaction between graphene oxide suspensions and a BH3 adduct in tetrahydrofuran under reflux. Elemental mapping images show well-dispersed B atoms along the materials. Various spectroscopic characterizations confirm the reduction of the graphene oxide and incorporation of B atoms into the carbon network as high as ~ 2 at%. The materials showed electrocatalytic activity for oxygen reduction reactions.

본 연구에서는 강화되는 황산화물 및 입자상물질의 배출규제를 만족시키기 위한 후처리장치로 습식전기집진기에 대한 실험적 연구를 수행하였다. 실험을 위해 선박용 중유(HFO, 황함유량 약 2.1%)를 연료로 사용하는 선박용 4행정 디젤엔진(STX-MAN B&W)을 활용 하였으며, 연돌에 설치된 습식전기집진기 입/출구에서 측정을 실시하였다. 미세먼지 측정을 위해서는 광학식 계측기(OPA-102) 및 중량농 도측정방식(Method 5 Isokinetic Train)을 이용하였으며, 황산화물 계측을 위해서는 FT-IR(DX-4000)을 사용하였다. 엔진부하는 50%, 75%, 100%로 변화시키면서 실험을 실시하였다. 실험 결과로, 엔진부하가 50%에서 100%로 변화함에 따라 미세먼지 저감 효율은 모든 부하 조건에서 94~98% 정도의 높은 저감 효율을 나타내었다. 추가적으로 습식전기집진기 퀜칭존에서 배기가스의 온도를 낮추는 과정 중 세정액에 의한 이산화황(SO2) 저감을 확인할 수 있었으며, 저감율은 엔진부하에 따라 55%~81%로 확인되었다.

This study investigated the physicochemical properties and acceptability of yellow layer cake prepared using various levels of wet-milled rice flour (RF). RF was used to substitute 0% (control group), 15% (RF-15 group), 30% (RF-30 group) and 45% (RF-45 group) of wheat flour (WF) to manufacture yellow layer cakes. The substitution of WF with RF showed no significant effect on the pH but decreased the specific gravity and viscosity of the batter. Baking loss rates ranged from 4.65% to 5.03%, showing no significant difference among samples. In the color measurement, the experimental groups showed higher redness (a) and yellowness (b) than the control group (p<0.05). The experimental groups showed lower gumminess and chewiness than the control group. According to the results of intensity measurement of sensory properties, the RF-30 and RF-45 groups showed stronger intensities for darkness, sweetness, moistness and softness than the control group. The acceptance test found that the RF-45 group had significantly higher or similar results for all acceptance attributes than the control group. These results indicate that RF addition as a replacement of WF at a ratio of 45% is optimal for producing yellow layer cakes.

In this work, TiO2 3D nanostructures (TF30) were prepared via a facile wet chemical process using ammonium hexafluorotitanate. The synthesized 3D TiO2 nanostructures exhibited well-defined crystalline and hierarchical structures assembled from TiO2 nanorods with different thicknesses and diameters, which comprised numerous small beads. Moreover, the maximum specific surface area of TiO2 3D nanostructures was observed to be 191 m2g-1, with concentration of F ions on the surface being 2 at%. The TiO2 3D nanostructures were tested as photocatalysts under UV irradiation using Rhodamine B solution in order to determine their photocatalytic performance. The TiO2 3D nanostructures showed a higher photocatalytic activity than that of the other TiO2 samples, which was likely associated with the combined effects of a high crystallinity, unique features of the hierarchical structure, a high specific surface area, and the advantage of adsorbing F ions.

As a case study on aspect ratio behavior, Kaolin, zeolite, TiO2, pozzolan and diatomaceous earth minerals are investigated using wet milling with 0.3 mm media. The grinding process using small media of 0.3 pai is suitable for current work processing applications. Primary particles with average particle size distribution D50, ~6 μm are shifted to submicron size, D50 ~0.6 μm after grinding. Grinding of particles is characterized by various size parameters such as sphericity as geometric shape, equivalent diameter, and average particle size distribution. Herein, we systematically provide an overview of factors affecting the primary particle size reduction. Energy consumption for grinding is determined using classical grinding laws, including Rittinger's and Kick's laws. Submicron size is obtained at maximum frictional shear stress. Alterations in properties of wettability, heat resistance, thermal conductivity, and adhesion increase with increasing particle surface area. In the comparison of the aspect ratio of the submicron powder, the air heat conductivity and the total heat release amount increase 68 % and 2 times, respectively.

생육, 습식 숙성육, 건식 숙성육을 종류별 3종을 구입하여 냉장 상태로 보관하면서 pH, 휘발성 염기질소(VBN), 미생물 정량, 우점균을 분석하였다. 초기 생육, 건식 숙성 육의 중온균은 3.3-3.9 Log CFU/g, 습식 숙성육은 경우 5.4 Log CFU/g 이였으나, 냉장으로 18일 보관 후 생육과 건식 숙성육에 존재하는 중온균은 6.1-6.4 Log CFU/g로 증가하였다. 습식 숙성육의 경우 Lactic acid bacteria (LAB) 는 냉장 보관시 4.5-6.0 Log CFU/g으로 나타났으나, 건식 숙성육에서는 검출되지 않았다. 저장 기간이 길어짐에 따라 중온균, 저온균, LAB, 효모 및 곰팡이 수가 증가하였으나, 식품매개 병원성 미생물은 검출되지 않았다. 식육의 오염 및 부패 판단은 7 Log CFU/g 이상으로 규정하고 있어 본 연구 결과에 의하면 12일 이상 냉장 보관하였을 경우 6-7 Log CFU/g으로 기준을 초과하였다. 이 때 VBN이 평균 15 mg%으로 부패의 초기 단계로 판단 할 수 있었다. 냉장 보관에 따른 우점 미생물은 다양한 양상으로 나타냈 다. 생육에서는 초기 우점균으로 S. saprophyticus가 분석 되었으나, VBN이 증가함에 따라 Carnobacterium divergens 가 우점하는 양상을 나타냈다. 습식 숙성육에서 Carnobacterium divergens가 냉장보관 초기에 우점 미생물로 분석되었으나, 이후 Lactobacillus sakei가 우점균으로 분석되었다. 건식 숙성육의 경우 Dermacoccus nishinomiyaensis 가 냉장보관 초기에 우점하였으나 이후 Pseudomonas fragi 가 우점균으로 변화하였다. 부패의 초기 단계에서 특정 박 테리아의 역할 외에도 부패, 향기 분석 및 숙성 육류의 성분 변화에 대한 연구를 수행하여 숙성 육류의 안전한 유통 및 보관에 활용할 수 있다고 판단된다.

A facile one-pot wet chemical process to prepare pure anatase TiO2 hollow structures using ammonium hexafluorotitanate as a precursor is developed. By defining the formic acid ratio, we fabricate TiO2 hollow structures containing fluorine on the surface. The TiO2 hollow sphere is composed of an anatase phase containing fluorine by various analytical techniques. A possible formation mechanism for the obtained hollow samples by self-transformation and Ostwald ripening is proposed. The TiO2 hollow structures containing fluorine exhibits 1.2 - 2.7 times higher performance than their counterparts in photocatalytic activity. The enhanced photocatalytic activity of the TiO2 hollow structures is attributed to the combined effects of high crystallinity, specific surface area (62 m2g-1), and the advantage of surface fluorine ions (at 8%) having strong electron-withdrawing ability of the surface ≡ Ti-F groups reduces the recombination of photogenerated electrons and holes.

In this study, the quality characteristics and antioxidant activities of wet noodles added with doraji (Platycodon grandiflourm) powder at concentrations of 1%, 2%, 3%, and 4%, respectively, were investigated. The crude protein, crude fat, crude ash, crude fiber, and moisture contents of the dried doraji powder were 11.00%, 0.95%, 4.10%, 29.64%, and 6.21%, respectively. As the added amount of doraji powder increased, weight, volume, and water absorption of the wet noodles after cooking decreased. However, the turbidity of the soup increased. Color L values of wet and cooked noodles decreased, while a and b values increased by the addition of doraji powder. Texture measurement indicated that hardness, cohesiveness, springiness, and chewiness of the cooked noodles decreased by addition of doraji powder. The total polyphenol contents and DPPH radical scavenging activity in wet noodles added with doraji powder increased with increasing amounts of doraji powder. Finally, sensory evaluation of wet noodles added with doraji powder revealed that taste significantly decreased. However, flavor, color, texture, appearance, and overall acceptance scores for the 1% addition group ranked significantly higher than those of the other groups. In conclusion, these findings suggest that doraji powder could be used as functional food ingredients.

The objective of this study was to investigate the effects of dry-aging and wet-aging conditions on the chemical composition, meat quality traits (color, water holding capacity, cooking loss, WBSF and pH) and shelf-life TBARS (2-thiobarbituric acid reactive substances) and VBN (volatile basic nitrogen) of loin (M. longissimus thoracis), sirloin (M. glutaeusmedus) and top-round (M. semimembranosus) cuts of Hanwoo cows. The dry-aging condition (temperature ℃, relative humidity %) was done for 60 d as 2℃, 65％, 20 d＋2℃, 75％, 20 d＋4℃, 85％, 20 d while, the wet-aging was done for 60 d at 1℃, 85%. Results revealed that moisture content was significantly higher in the dry-aged samples than that of the wet-aged samples at 60 d (p<0.05). The a*- and b*-values were significantly higher in 3 cuts as compared with those treated with wet-aging condition. During the dry-aging time, the WHC significantly increased in the loin and sirloin and they were significantly higher than wet-aging condition at 40 d and 60 d (p<0.05). The WBSF values significantly decreased with increased aging time and there was no significant difference between two aging methods. The TBARS and VBN contents significantly increased with increased aging time for all the wet- and dry-aged cuts, and their levels still fell within the acceptable standard limit. Generally, the TBARS and VBN contents were significantly higher in the dry-aged cuts, probably due to the increased levels of protein and fatty acids oxidations. Based on the results obtained in the present study, it can be suggested that application of dry-aging method can improve the quality characteristics of beef.