• Title/Summary/Keyword: specific surface

검색결과 3,823건 처리시간 0.034초

The Activity of Standard and Fast SCR over V-based Catalysts Supported on Various TiO2 (다양한 TiO2에 담지된 바나디아 촉매의 표준 및 빠른 SCR 활성)

  • Ji Eun Jeong;Yeon Jeong Jo;Inyoung Lee;Jeongkeun Lee;Chang-Yong Lee
    • Applied Chemistry for Engineering
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    • 제34권6호
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    • pp.584-589
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    • 2023
  • The physicochemical properties of VOx/TiO2 catalysts with different TiO2 supports were analyzed, and SCR reactions were performed. VOx/TiO2 catalysts were prepared by impregnation using anatase TiO2, which was manufactured by Sigma Aldrich and prepared from TiOCl2 and titanium isopropoxide (TTIP) as a precursor. They are denoted as VS, VC, and VP. The specific surface area of the VS was 1/10 or less of that of the VC and VP, and the dispersibility of vanadium oxide was relatively low. As a result of XPS analysis, the ratio of adsorbed oxygen was higher in VS and VP with Ti3+ than in VC. In VC and VP, vanadium mainly existed in V4+ and V3+ states in relation to the dispersibility of vanadium oxide. The amount of adsorbed oxygen contributed more to NH3-SCR activity than vanadium oxide dispersibility below 250 ℃, while vanadium oxide dispersibility contributed more to activity beyond 300 ℃. The fast SCR activity in all three samples was the highest at NO2/NOx = 0.5, followed by VS < VC < VP samples. It was determined that the dispersibility of vanadium oxide had a significant effect on fast NH3-SCR activity.

Effect of Co-catalyst CeO2 on NOx Reduction in PtNi/W-TiO2 Catalysts for Low-temperature H2-SCR (저온 H2-SCR용 PtNi/W-TiO2 촉매에 조촉매 CeO2가 NOx 저감에 미치는 영향)

  • Jungsoo Kim;Younghee Kim
    • Clean Technology
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    • 제29권4호
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    • pp.313-320
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    • 2023
  • In order to increase the usability of H2-SCR, the NOx removal characteristics with catalyst powder of PtNi/CeO2-W-TiO2 using Ce as a co-catalyst was synthesized and coated on a porous metal structure (PMS) were evaluated. Catalyst powder of PtNi/CeO2-W-TiO2(PtNi nanoparticles onto W-TiO2, with the incorporation of ceria (CeO2) as a co-catalysts) was synthesized and coated onto a porous metal structure (PMS) to produce a Selective Catalytic Reduction (SCR) catalyst. H2-SCR with CeO2 as a co-catalyst exhibited higher NOx removal efficiency compared to H2-SCR without CeO2. Particularly, at a 10wt% CeO2 loading ratio, the NOx removal efficiency was highest at 90℃. As the amount of catalyst coating on PMS increased, the NOx removal efficiency was improved below 90℃, but it was decreased above 120℃. When the space velocity was changed from 4,000 h-1 to 20,000 h-1, the NOx removal efficiency improved at temperatures above 120℃. It was expected that the use of the catalyst could be reduced by applying the PMS with excellent specific surface area as a support.

Study of the Static Shear Behaviors of Artificial Jointed Rock Specimens Utilizing a Compact CNS Shear Box (Compact CNS shear box를 활용한 모의 절리암석시료의 정적 전단 거동에 관한 연구)

  • Hanlim Kim;Gyeongjo Min;Gyeonggyu Kim;Youngjun Kim;Kyungjae Yun;Jusuk Yang;Sangho Bae;Sangho Cho
    • Tunnel and Underground Space
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    • 제33권6호
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    • pp.574-593
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    • 2023
  • In this study, the effectiveness and applicability of a newly designed Compact CNS shear box for conducting direct shear tests on jointed rock specimens were investigated. CNS joint shear tests were conducted on jointed rocks with Artificially generated roughness while varying the fracture surface roughness coefficient and initial normal stress conditions. In addition, displacement data were validated by Digital image correlation analysis, fracture patterns were observed, and comparative analysis was conducted with previously studied shear behavior prediction models. Furthermore, the accuracy of the displacement data was confirmed through DIC analysis, the fracture patterns were observed, and the shear properties obtained from the tests were compared with existing models that predict shear behavior. The findings exhibited a strong correlation with specific established empirical models for predicting shear behavior. Furthermore, the potential linkage between the characteristics of shear behavior and fracture patterns was deliberated. In conclusion, the CNS shear box was shown to be applicable and effective in providing data on the shear characteristics of the joint.

Effect of body weight at photostimulation on productive performance and welfare aspects of commercial layers

  • Fazal Raziq;Jibran Hussain;Sohail Ahmad;Muhammad Asif Hussain;Muhammad Tahir Khan;Assad Ullah;Muhammad Qumar;Fazal Wadood;Gull-e-Faran
    • Animal Bioscience
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    • 제37권3호
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    • pp.500-508
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    • 2024
  • Objective: Due to current selection practices for increased egg production and peak persistency, the production profile, age at maturity, and body weight criteria for commercial layers are constantly changing. Body weight and age at the time of photostimulation will thus always be the factors that need to be adequately addressed among various production systems. The current study was carried out to determine the effects of pullets' body weight (low, medium, and heavy) on their performance, welfare, physiological response, and hormonal profile. Methods: With regard to live weight, 150 16-week-old pullets were divided into three groups using a completely randomized design (CRD) and held until the 50th week. One-way analysis of variance was used to evaluate the data under the CRD, and the least significant difference test was used to distinguish between treatment means. Results: In comparison to the medium and light birds, the heavy birds had higher body weight at maturity, an earlier age at maturity, and higher egg weight, eggshell weight, eggshell thickness, egg yolk index, breaking strength, egg surface area, egg shape index, egg volume, and hormonal profile except corticosterone. However, the medium and light birds had lower feed consumption rates per dozen eggs and per kilogram of egg mass than the heavy birds. Light birds showed greater body weight gain, egg production, and egg specific gravity than the other categories. At 20 weeks of age, physiological response, welfare aspects, and catalase were non-significant; however, at 50 weeks of age, all these factors-aside from catalase-were extremely significant. Conclusion: The findings of this study indicate that layers can function at lower body weights during photostimulation; hence, dietary regimens that result in lighter pullets may be preferable. Additionally, the welfare of the birds was not compromised by the lighter weight group.

Geotechnical Properties of Pelagic Red Clay in Northeast Equatorial Pacific (북동태평양 원양성 적점토의 지질공학적 특성에 관한 연구)

  • Chi, Sang-Bum;Lee, Hyun-Bok;Hyeong, Ki-Seong;Ju, Se-Jong;Lee, Gun-Chang;Ham, Dong-Jin
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • 제13권3호
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    • pp.286-294
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    • 2008
  • In order to understand the physical properties of deep-sea sediments, which mainly consist of pelagic red clays, sediment samples were collected at 24 stations using a multiple corer in the Clarion-Clipperton fracture zone of the northeast equatorial Pacific. The sampled sediment cores were examined for the mass physical properties(i.e. grain size distribution, mean grain size, water content, specific grain density, wet bulk density, void ratio, and porosity) and the geotechnical properties(i.e. shear strength and consistency limits) with the content of biogenic opal and mineral composition. Although KR1 and KR2 areas on the same latitude are logitudinally far from each other, the mass physical properties of these areas are not distinctly different except for shear strengths. The maximum shear strength of surface sediments in KR2 area is higher than that in KR1 due to the appearance of a consolidated lower layer(Unit 3) in the sediment core from KR2.

Effect of Acid Treatment on Pd/C Catalysts for Improving Selective Hydrogenation of Phenol (페놀의 선택적 수소화 반응성 향상을 위한 Pd/C 촉매의 산 처리 효과)

  • Hayoon Park;Ye Eun Kim;Jungho Jae;Man Sig Lee
    • Clean Technology
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    • 제30권2호
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    • pp.145-156
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    • 2024
  • Carbon has a large specific area and excellent chemical stability, so research on its use as a catalyst support is actively conducted. When using carbon as a support, the pretreatment process is essential. Through pretreatment of carbon, the growth of metal nanoparticles can be controlled and the bonding strength between the support and metal particles can be improved. In this study, carbon was pretreated for surface modification and 5 wt% Pd/C catalysts were synthesized using it as a support. Catalytic activity was evaluated through phenol hydrogenation. To compare with nitric acid, which is commonly used in carbon pretreatment, carbon pretreatment was performed using organic acid. Pd/C treated with gluconic acid showed the highest activity, with 94.93% phenol conversion and 92.76% cyclohexanone selectivity. Therefore, it is expected that pretreatment of the carbon support using organic acid will not only overcome the disadvantages of inorganic acid treatment but also improve catalyst performance.

Examining the Role of ZO Protein in the Cancer Microenvironment (암 미세환경에서 ZO 단백질의 역할 고찰)

  • Min-Hye Kim;Hee-Jae Cha
    • Journal of Life Science
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    • 제34권4호
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    • pp.279-285
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    • 2024
  • The zonula occludens (ZO) protein serves as a scaffolding protein, providing structural support at the junctions between cells and the cytoplasmic surface. It acts as a bridge between integral membrane proteins and the cytoskeleton. Besides its structural role, it also participates in regulating cell growth and proliferation. Recent studies have highlighted the involvement of ZO protein in various diseases, including cancer. Specifically, research has indicated that ZO protein influences the cancer microenvironment surrounding cancer cells, thereby facilitating their growth and development. ZO proteins exert diverse functions in the cancer microenvironment, impacting processes such as angiogenesis, inflammatory responses, the epithelial-mesenchymal transition, and interactions with mesenchymal stem cells. The specific mechanisms vary depending on the type of cancer and environmental conditions. Recent research unveiled several signaling pathways involving ZO protein, which could potentially impede cancer progression in the tumor microenvironment. Consequently, these insights open avenues for novel treatment strategies. While the numerous physiological, structural, and morphological roles of ZO protein have been observed at the cellular and in vivo levels, understanding the signaling mechanisms it operates in vivo and how these mechanisms influence the cancer microenvironment remains a challenge. In this review, we delineate the characteristics and regulatory mechanisms of ZO protein in the context of the cancer microenvironment. Additionally, we propose leveraging the properties of ZO protein to devise defense mechanisms within the cancer cell environment and provide an overview of its in vivo role.

Comparison of Kinematics and Myoelectrical Activity during Deadlift, with and without Variable Banded Resistance, in Healthy, Trained Athletes

  • Everett B. Lohman;Mansoor Alameri;Fulden Cakir;Chih Chieh Chia;Maxine Shih;Owee Mulay;Kezia Marceline;Simran Jaisinghani;Gurinder Bains;Michael DeLeon;Noha Daher
    • Physical Therapy Rehabilitation Science
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    • 제13권1호
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    • pp.53-70
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    • 2024
  • Background: The conventional deadlift is a popular exercise for enhancing trunk, core, and lower extremity strength. However, its use in sports medicine is constrained by concerns of lumbar injuries, despite evidence supporting its safety and rehabilitative benefits. To optimize muscle activation using resistive bands in variable resistance therapy, we explored their feasibility in the deadlift. Design: Comparative experimental design Methods: Surface electromyography recorded muscle activity in the trunk and lower extremities during lifting, with normalization to the isometric Floor Lift using Maximal Voluntary Contraction. Kinematics were measured using inclinometer sensors to track hip and trunk sagittal plane angles. To prevent fatigue, each subject only used one of the three pairs of bands employed in the study. Results: Our study involved 45 healthy subjects (mean age: 30.4 ± 6.3 years) with similar baseline characteristics, except for years of lifting and strength-to-years-of-lifting ratio. Various resistance band groups exhibited significantly higher muscle activity than conventional deadlifts during different phases. The minimal resistance band group had notably higher muscle activity in the trunk, core, and lower extremity muscles, particularly in the end phase. The moderate resistance band group showed increased muscle activity in the mid-and end-phases. The maximum resistance band group demonstrated greater muscle activity in specific muscles during the early phase and overall higher activity in all trunk and lower extremity muscles in the mid and end phases of the deadlift (p<0.05). Conclusion: Our findings provide valuable insights into muscle activation with various resistance bands during deadlift exercise in clinical and gym settings. There appears to be a dose-response relationship between increased resistance bandwidth, external load, myoelectric activation, and range.

Smooth versus Textured Tissue Expanders: Comparison of Outcomes and Complications in 536 Implants

  • Omar Allam;Jacob Dinis;Mariana N. Almeida;Alexandra Junn;Mohammad Ali Mozaffari;Rema Shah;Lauren Chong;Olamide Olawoyin;Sumarth Mehta;Kitae Eric Park;Tomer Avraham;Michael Alperovich
    • Archives of Plastic Surgery
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    • 제51권1호
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    • pp.42-51
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    • 2024
  • Background Increasing concerns regarding the safety of textured surface implants have resulted in surgeons transitioning from textured tissue expanders (TEs) to smooth TEs. Given this change has only recently occurred, this study evaluated outcomes between smooth and textured TEs. Methods Women who underwent two-stage breast reconstruction using TEs from 2013 to 2022 were included. TE-specific variables, perioperative information, pain scores, and complications were collected. Chi-squared, t-test, and linear regression analyses were performed. Results A total of 320 patients received a total of 384 textured and 152 smooth TEs. Note that 216 patients received bilateral reconstruction. TEs were removed in 9 cases. No significant differences existed between groups regarding comorbidities. Smooth TEs had a higher proportion of prepectoral placement (p < 0.001). Smooth TEs had less fills (3±1 vs. 4±2, p < 0.001), shorter expansion periods (60±44 vs. 90±77 days, p < 0.001), smaller expander fill volumes (390±168 vs. 478±177 mL, p < 0.001), and shorter time to exchange (80±43 vs. 104±39 days, p < 0.001). Complication rates between textured and smooth TEs were comparable. Smooth TE had a greater proportion of TE replacements (p = 0.030). On regression analysis, pain scores were more closely associated with age (p = 0.018) and TE texture (p = 0.046). Additional procedures at time of TE exchange (p < 0.001) and textured TE (p = 0.017) led to longer operative times. Conclusion As many surgeons have transitioned away from textured implants, our study shows that smooth TEs have similar outcomes to the textured alternatives.

Effect of crude fibre additives ARBOCEL and VITACEL on the physicochemical properties of granulated feed mixtures for broiler chickens

  • Jakub Urban;Monika Michalczuk;Martyna Batorska;Agata Marzec;Adriana Jaroszek;Damian Bien
    • Animal Bioscience
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    • 제37권2호
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    • pp.274-283
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    • 2024
  • Objective: The aim of the study was to evaluate the physicochemical properties (nutrient composition, pH, water content and activity, sorption properties) and mechanical properties (compression force and energy) of granulated feed mixtures with various inclusion levels of crude fibre concentrates ARBOCEL and VITACEL for broiler chickens, i.e. +0.0% (control group - group C), +0.3%, +0.8%, +1.0%, +1.2%. Methods: The feed mixtures were analyzed for their physicochemical properties (nutrient composition by near-infrared spectroscopy, pH with the use a CP-401 pH meter with an IJ-44C glass electrode, water content was determined with the drying method and activity was determined with the Aqua Lab Series 3, sorption properties was determined with the static method) and mechanical properties (compression force and energy with the use TA-HD plus texture analyzer). The Guggenheim-Anderson-de Boer (GAB) model applied in the study correctly described the sorption properties of the analyzed feed mixtures in terms of water activity. Results: The fibre concentrate type affected the specific surface area of the adsorbent and equilibrium water content in the GAB monolayer (p≤0.05) (significantly statistical). The type and dose of the fibre concentrate influenced the dimensionless C and k parameters of the GAB model related to the properties of the monolayer and multilayers, respectively (p≤0.05). They also affected the pH value of the analyzed feed mixtures (p≤0.05). In addition, crude fibre type influenced water activity (p≤0.05) as well as compression energy (J) and compression force (N) (p≤0.001) (highly significantly statistical) of the feed mixtures. Conclusion: The physicochemical analyses of feed mixtures with various inclusion levels (0.3%, 0.8%, 1.0%, 1.2%) of crude fiber concentrates ARBOCEL or VITACEL demonstrated that both crude fiber types may be used in the feed industry as a feedstuff material to produce starter type mixtures for broiler chickens.