A new record of pasiphaeid shrimp of the genus <Emphasis Type="Italic">Pasiphaea</Emphasis> (Crustacea: Decapoda: Caridea) in Korean waters     

Jung Nyun Kim  Jung Hwa Choi  Hyun-su Jo 《Ocean Science Journal》2016,51(3):531-534

A single specimen of the pelagic shrimps, Pasiphaea japonica Omori, 1976 (Pasiphaeidae) collected in the southeastern waters of Korea is described and illustrated. Although this species occurs widely in the Indo-West Pacific including the Japanese coast of the East/Japan Sea and the middle and southern parts of the East China Sea, this is the first record of the species and the genus in Korean waters. The species is distinguished from other congeners by the following combination of characteristics: non-carinate dorsal sixth abdominal somite with a terminal tooth, rudimentary pleurobranch on the eighth thoracic somite, merus of the first pereopod with more than eight spines, and almost entirely transparent white color.  相似文献   

Field Evaluation of the Vertical Bearing Capacity of a Screw Pretensioned Spun High-Strength Concrete Pile     

Yongkyu Choi  Dong-Chul Kim  Tae-Hyung Kim 《Marine Georesources & Geotechnology》2016,34(5):474-485

This study has evaluated the vertical bearing capacity by conducting static load tests for noise-free and vibration-free screw pretensioned spun high-strength concrete (PHC) piles installed using two different methods (end-squirting shoe and pre-boring methods). Vertical bearing capacity differences seem to occur due to the displacement of soils near the external circumference of a pile, depending on the installation method. A method by which to evaluate the bearing capacity of screw concrete piles is suggested by considering the equations that already have been used to calculate the bearing capacity of piles. Based on static load tests and analysis, the pile installed using the end-squirting shoe method was assumed to be a bored pile and it was reasonable to use the equation proposed by the Japanese Geotechnical Society. At the same time, the pile installed using the pre-boring method was deemed a low soil displacement pile and so it was reasonable to apply the equations proposed for calculating the bearing capacity of the driven pile suggested by the Architectural Institute of Japan.  相似文献   

Thermal effects on the growth and fatty acid composition of four harmful algal bloom species: Possible implications for ichthyotoxicity     

Bonggil Hyun  Se-Jong Ju  Ah-Ra Ko  Keun-Hyung Choi  Seung Won Jung  Pung-Guk Jang  Min-Chul Jang  Chang Ho Moon  Kyoungsoon Shin 《Ocean Science Journal》2016,51(3):333-342

Little is known regarding how harmful algal bloom species respond to different temperatures in terms of fatty acid production. This study examined the effects of temperature on the growth rates, cell volumes, and fatty acid concentrations and compositions of four harmful algal bloom species (HABs), Akashiwo sanguinea, Alexandrium tamarense, Chattonella ovata, and Prorocentrum minimum. The HABs species were cultured at 15, 20, 25, and 30°C in a nutrient-enriched medium. Three of the species maintained optimal growth rates over a wide range of temperatures, but A. tamarense did not. The cell volumes of each species showed little change over the temperature range. The total fatty acid concentrations in A. sanguinea, A. tamarense and C. ovata decreased as the temperature increased, but P. minimum showed no trend in this respect. Polyunsaturated fatty acids (PUFAs), the key biochemical components that maintain cell membrane fluidity and which are associated with toxicity, decreased in both concentration and proportion of total fatty acids as temperature increased, except in A. sanguinea, in which the proportion of PUFAs to the total fatty acids increased. These reductions in PUFA concentration and proportion could reduce cell membrane fluidity and toxicity in HABs; however, enhanced growth and/or ruptured cells, which are considered more toxic than intact cells, could compensate for the reduced per-cell toxicity. This phenomenon might impact on the marine ecosystem and aquaculture industry.  相似文献   

Predicting rock size distribution in mine blasting using various novel soft computing models based on meta-heuristics and machine learning algorithms     

Chengyu Xie  Hoang Nguyen  Xuan-Nam Bui  Yosoon Choi  Jian Zhou  Thao Nguyen-Trang 《地学前缘(英文版)》2021,12(3):101108

Blasting is well-known as an effective method for fragmenting or moving rock in open-pit mines. To evaluate the quality of blasting, the size of rock distribution is used as a critical criterion in blasting operations. A high percentage of oversized rocks generated by blasting operations can lead to economic and environmental damage. Therefore, this study proposed four novel intelligent models to predict the size of rock distribution in mine blasting in order to optimize blasting parameters, as well as the efficiency of blasting operation in open mines. Accordingly, a nature-inspired algorithm (i.e., firefly algorithm – FFA) and different machine learning algorithms (i.e., gradient boosting machine (GBM), support vector machine (SVM), Gaussian process (GP), and artificial neural network (ANN)) were combined for this aim, abbreviated as FFA-GBM, FFA-SVM, FFA-GP, and FFA-ANN, respectively. Subsequently, predicted results from the abovementioned models were compared with each other using three statistical indicators (e.g., mean absolute error, root-mean-squared error, and correlation coefficient) and color intensity method. For developing and simulating the size of rock in blasting operations, 136 blasting events with their images were collected and analyzed by the Split-Desktop software. In which, 111 events were randomly selected for the development and optimization of the models. Subsequently, the remaining 25 blasting events were applied to confirm the accuracy of the proposed models. Herein, blast design parameters were regarded as input variables to predict the size of rock in blasting operations. Finally, the obtained results revealed that the FFA is a robust optimization algorithm for estimating rock fragmentation in bench blasting. Among the models developed in this study, FFA-GBM provided the highest accuracy in predicting the size of fragmented rocks. The other techniques (i.e., FFA-SVM, FFA-GP, and FFA-ANN) yielded lower computational stability and efficiency. Hence, the FFA-GBM model can be used as a powerful and precise soft computing tool that can be applied to practical engineering cases aiming to improve the quality of blasting and rock fragmentation.  相似文献   

Effects of particle shape on the cushioning mechanics of rock-filled gabions     

Su  Yuchen  Choi  Clarence E. 《Acta Geotechnica》2021,16(4):1043-1052

Acta Geotechnica - Rock-filled gabions are commonly installed in front of reinforced concrete structures to reduce concentrated impact loads induced by rock fall and boulders entrained in debris...  相似文献   

Distribution and Sources of Dissolved and Particulate Heavy Metals (Mn,Co, Ni,Cu, Zn,Cd, Pb) in Masan Bay,Korea     

Park  Sojung  Choi  Mansik  Jang  Dongjun  Joe  Dongjin  Park  Kyunggue 《Ocean Science Journal》2020,55(1):49-67

Ocean Science Journal - In this study, we investigated the spatial and temporal distribution and sources of dissolved and particulate heavy metals in Masan Bay, an area that for a long time has...  相似文献   

Molecular Identification and Expression Analysis of Carbonic Anhydrase VII in Pufferfish (Takifugu rubripes)     

Sumi  Kanij Rukshana  Kim  Soo Cheol  Howlader  Jewel  Sharker  Md Rajib  Choi  Kap Seong  Choi  Sang Ki  Park  Jong-In  Nou  Ill-Sup  Kho  Kang Hee 《Ocean Science Journal》2019,54(3):363-374

Ocean Science Journal - A carbonic anhydrase VII gene, encoding 277 amino acids, was identified in the intestinal tissue of pufferfish (Takifugu rubripes). The translated protein with an 833-bp...  相似文献   

Quantitative Analysis of Micro-structural Changes in a Bituminous Coal After Exposure to Supercritical CO2 and Water     

Zhang  Guanglei  Ranjith  P. G.  Perera  M. S. A.  Lu  Yiyu  Choi  Xavier 《Natural Resources Research》2019,28(4):1639-1660

Natural Resources Research - High-volatile bituminous coal samples were reacted in deionized water with supercritical CO2 (ScCO2–water) under simulated in situ pressure and temperature...  相似文献   

Underwater autonomous manipulation for intervention missions AUVs   总被引：1，自引：0，他引：1  

Giacomo Marani  Song K. Choi  Junku Yuh 《Ocean Engineering》2009,36(1):15-23

Many underwater intervention tasks are today performed using manned submersibles or remotely operated vehicles in teleoperation mode. Autonomous underwater vehicles are mostly employed in survey applications. In fact, the low bandwidth and significant time delay inherent in acoustic subsea communications represent a considerable obstacle to remotely operate a manipulation system, making it impossible for remote controllers to react to problems in a timely manner.Nevertheless, vehicles with no physical link and with no human occupants permit intervention in dangerous areas, such as in deep ocean, under ice, in missions to retrieve hazardous objects, or in classified areas. The key element in underwater intervention performed with autonomous vehicles is autonomous manipulation. This is a challenging technology milestone, which refers to the capability of a robot system that performs intervention tasks requiring physical contacts with unstructured environments without continuous human supervision.Today, only few AUVs are equipped with manipulators. SAUVIM (Semi Autonomous Underwater Vehicle for Intervention Mission, University of Hawaii) is one of the first underwater vehicle capable of autonomous manipulation.This paper presents the solutions chosen within the development of the system in order to address the problems intrinsic to autonomous underwater manipulation. In the proposed approach, the most noticeable aspect is the increase in the level of information transferred between the system and the human supervisor.We describe one of the first trials of autonomous intervention performed by SAUVIM in the oceanic environment. To the best knowledge of the authors, no sea trials in underwater autonomous manipulation have been presented in the literature. The presented operation is an underwater recovery mission, which consists in a sequence of autonomous tasks finalized to search for the target and to securely hook a cable to it in order to bring the target to the surface.  相似文献   

Coastal environmental assessment and management by ecological simulation in Yeoja Bay, Korea     

Dae-In Lee  Jeong-Min Choi  Yeon-Gyu Lee  Moon-Ock Lee  Won-Chan Lee  Jong-Kyu Kim   《Estuarine, Coastal and Shelf Science》2008,80(4):495-508

An eco-hydrodynamic model was used to estimate the carrying capacity of pollutant loads and response of water quality to environmental change in Yeoja Bay, Korea. An energy-system model also was used to simulate the fluctuation in nutrients and organic matter in the bordering wetland. Most water quality factors showed a pulsed pattern, and the concentrations of nutrients and organic matter of seawater increased when input loads of nutrients increased due to freshwater discharge. The well-developed tidal zones and wetlands in the northern area of the bay were highly sensitive to input loads. Residence times of water, chemical oxygen demand (COD), and dissolved inorganic nitrogen (DIN) within the bay were estimated to be about 16 days, 43.2 days, and 50.2 days, respectively. Water quality reacted more sensitively to the effects of nitrogen and phosphorus input than to COD. A plan to reduce the present levels of COD and dissolved inorganic phosphorus (DIP) by 20–30% and DIN by at least 50% in pollutant loads is needed for satisfying the target water quality criteria. The natural removal rate of nutrients in wetlands by reeds was assessed to be approximately 10%.  相似文献