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811.
812.
Philip J. Valent David K. Young William B. Sawyer Thomas D. Wright 《Journal of Marine Systems》1998,14(3-4)
The Naval Research Laboratory (NRL), with industry and university participation, conducted an assessment of the concept of isolating certain wastes (i.e., sewage sludge, fly ash from municipal incinerators, and contaminated dredged material) on the oceans' abyssal seafloor. In this assessment the advantages, disadvantages, and economic and environmental viability of potential engineering methods for achieving abyssal waste isolation were identified and compared. This paper presents background to the Abyssal Plains Waste Isolation (APWI) Project, describes the characteristics of the waste streams and quantities potentially available for disposal via the abyssal isolation concept, summarizes regulations affecting use of the abyssal seafloor for disposal of wastes, and introduces the technical and scientific premises underlying implementation of the concept. 相似文献
813.
Jung-Hwan Lee 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,33(6):373-390
In the dynamic simulation of vehicle straight line motion, a vehicle model usually drifts from its intended straight path even in the case of no external input. This is particularly true when a tire model based on experimental data is used. The purpose of this paper is to provide an enhancement of a basic understanding of a tire/vehicle system behavior in the straight line motion and to identify the effect of the tire on that motion. Through the analysis of a two degrees of freedom vehicle model, tire characteristic which causes a lateral drift in the straight line motion is identified. Then the results are confirmed from vehicle test and the simulations with a more complex full-car model. 相似文献
814.
In this paper we address the following question: how much is a ship-owner willing to pay in order to convert his single-hull vessel to a double-hull vessel? Our research is motivated by a recent article in Tradewinds, according to which owners have become reluctant in scrapping their vessels by turning them into double hull from single hull. We apply a structural no-arbitrage condition for deriving and estimating 'good-deal' bounds. 相似文献
815.
816.
In this article, we analyze the linear stability of tandem offloading systems in wind, current, and waves. The wind and current forces are evaluated with the help of published experimental data, while the hydrodynamic coefficients and wave drift forces are rigorously estimated by using a three-dimensional singularity distribution method based on potential theory. The bow hawser and mooring lines are described quasistatically by elastic catenary equations. In order to examine the linear static and dynamic stability of the system, the equations for surge, sway, and yaw are linearized. The effect of design parameters such as turret position, mooring stiffness, and hawser length and stiffness on stability is investigated based on linearized model. The stability analysis clarifies the mechanism of the limit cycle for tandem offloading systems, which is known as fishtailing motion. The theoretical results of the shape and amplitude of the limit cycle are found to be in good agreement with those of simulations and experiments. 相似文献
817.
This paper aims to analyze the charter contract management of major container shipping companies in response to fluctuations in shipping market conditions in terms of contract duration using data of containerships between 2010 and 2016. Duration analysis was conducted to examine the relationship between charter duration and shipping market conditions. Moreover, this paper explores the causes of Hanjin Shipping Company’s bankruptcy, drawing managerial implications. Test results from Cox PH (Proportional Hazard) model show that most container shipping companies in Europe having net earnings purchased large vessels instead of chartering vessels, while some ocean carriers featuring poor financial performance, in particular the Hanjin Shipping Company, chartered bigger ships with higher charter rates and longer duration. Contract charter rates and duration of Hanjin Shipping Company featured greater risk compared to competitors. 相似文献
818.
Learning-based traffic control algorithms have recently been explored as an alternative to existing traffic control logics. The reinforcement learning (RL) algorithm is being spotlighted in the field of adaptive traffic signal control. However, no report has described the implementation of an RL-based algorithm in an actual intersection. Most previous RL studies adopted conventional traffic parameters, such as delays and queue lengths to represent a traffic state, which cannot be exactly measured on-site in real time. Furthermore, the traffic parameters cannot fully account for the complexity of an actual traffic state. The present study suggests a novel artificial intelligence that uses only video images of an intersection to represent its traffic state rather than using handcrafted features. In simulation experiments using a real intersection, consecutive aerial video frames fully addressed the traffic state of an independent four-legged intersection, and an image-based RL model outperformed both the actual operation of fixed signals and a fully actuated operation. 相似文献
819.
The goal of this research is to investigate the application of low-cost climate control seats (CCSs) using a Heating, Ventilation and Air-conditioning system (HVAC). CCSs are being vigorously developed because demands on passengers’ thermal comfort are increasing recently. Nevertheless, current CCSs–thermo-electric devices (TED) that have been applied for both heating and cooling systems, have been used in limited luxury cars only. HVAC-type CCSs are proper for effective delivery of conditioned air due to thermal comfort and close proximity to passengers. In this study, experimental results show that HVAC-type CCSs have superior cooling performance and slightly worse heating performance than that of TED-type CCSs. In the case of HVAC-type CCSs, compared to TED-type CCSs, airflow volume was increased approximately 3.7–7.3 m3/h and surface temperature of seats was reduced by about 5 °C. And the maximum cool-down performance of HVAC-type CCSs was similar to the Base (Non HVAC-type CCSs). In addition, in passengers’ subjective evaluation, the HVAC-type CCSs, the former recorded twelve minutes to reach the comfort rate five both in cooling and heating test, meanwhile, TED-type CCSs are nineteen minutes and ten minutes each both in the cooling and heating test. 相似文献
820.