검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 839

        88.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Novel eco-friendly adsorbents were prepared through pyrolysis and acid activation of raw almond leaf (RAL) to form almond leaf biochar (ALB) and chemically activated almond leaf biochar (CAL), respectively. The prepared adsorbents were characterized using TGA, FTIR, SEM–EDX, BET and XRD techniques and their physicochemical properties investigated. RAL, ALB and CAL were utilized for adsorption of BPB dye from aqueous solution using batch technique under optimum conditions. The optimum dye adsorbed by RAL, ALB and CAL were 92.83, 93.21 and 94.89%, respectively at pH 3, dye initial conc. (100 mg/L), adsorbent dose (0.04 g/25 mL), 60 min contact time and 301 K adsorption temperature. Although, Langmuir maximum monolayer adsorption capacities were found to be 365.36, 535.62 and 730.46 mg/g for RAL, ALB and CAL, respectively, but isotherm conformed to Freundlich model. Kinetic study confirmed suitability of pseudo-second-order model with rate constant 9.33 × 10–4, 9.91 × 10–4 and 12.60 × 10−4 g mg−1 min−1 for RAL, ALB and CAL, respectively. Negative values of thermodynamic parameters (ΔG and ΔH) established sequestration process to be spontaneous and exothermic. RAL, ALB and CAL were discovered to be highly efficient adsorbents that could be used in place of expensive commercial adsorbents.
        4,600원
        89.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        COVID-19가 전 세계를 강타하면서 각 국가는 대혼란에 빠졌다. 전 세계 화물교역은 80 % 이상이 해상운송을 통해 이루어지고 있어 화물과 여객을 포함한 해상운송업은 COVID-19의 큰 영향을 받는 산업으로 예측되었다. 따라서 본 연구의 목적은 코로나 팬데믹 (Coronavirus Pandemic) 발생 전후로 아시아 주요 항만 컨테이너 항구의 팬데믹 전후 운영효율성을 분석하는 것이다. 항만의 운영효율성을 분석하기 위해서 자료포락분석(DEA)을 이용하였다. 본 연구의 분석 기간은 5년(2016~2020년)으로 2016년, 2017년, 2018년, 2019년을 코로나 이전으로 하고, 2020년을 포스트 코로나 시대로 설정하였다. 또한, 분석 대상으로는 아시아 상위 10개 항구 중 동종 DMU의 DEA 요건을 충족시킨 상하이, 광저우, 선전, 닝보-저우산, 부산 및 싱가포르 총 7개 항구를 선택하였다. DEA의 CCR 및 BCC 모델의 결과는 몇 가지 비효율성이 확인되었음에도 COVID-19 팬데믹 발생 시점에서 몇 개월 이후부터는 전반적으로 운영효율성이 코로나 이전 몇 년 동안보다 상대적으로 높았음을 확인하였다. 하지만 일부 항만 (부산, 광저우)의 경우에는 더욱 나은 운영효율성을 위해서 항만의 규모와 운영의 기술적 능력 등을 제고 할 필요가 있다.
        4,300원
        98.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the effect of rumen origin lactate-utilizing bacteria (LUB) as one of the potential treatments on subacute ruminal acidosis (SARA) during in vitro challenge compared to buffering agents (NaHCO3, sea minerals, MgO) and direct-fed microorganism (yeast). We hypothesized that rumen LUB (RLUB) could be a potential treatment to treat ruminal acidosis. The supplementation level of other treatments was determined by referring to previous studies in the literature. The 108 CFU/g freeze-dried RLUB isolated from Hanwoo cattle were compared with 0.1% NaHCO3, 0.8% of MgO, 0.5% sea mineral and 0.4% yeast during in vitro SARA challenge. Rumen fluid collected from one cannulated Holstein and one Hanwoo steer fed by maize silage was mixed with 0.5g feed consisted of 0.05g forage and 0.45g concentrate. These mixtures were incubated in triplication for 3, 6, 12 and 24h. After 6h of incubation, along with MgO and sea minerals, RLUB treatment showed higher (p<0.05) ㏗ values than control with no significant differences in total volatile fatty acid concentration. However, in the same period, the propionate concentration and A:P ratio were higher in RLUB than in the other treatment (p<0.05), which might alter the fermentation pattern. On the other hand, the RLUB treatment produced a higher (p<0.05) ammonia-N concentration. Based on these results, we can conclude that RLUB might have the potential to alleviate SARA. Nonetheless, further study on its mechanism in SARA is required, especially with live animals.
        4,000원
        1 2 3 4 5