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861.
This study describes an automatic berthing system with mooring lines. It is designed to be berthed by using mooring device on the upper deck of a ship. It is to berth once maintaining parallel with the quay by controlling both forward and aft breast lines. Berthing method is used through length adjustment of mooring lines connected between ship and quay by controlling the angular velocity and the torque of hydraulic motor in mooring device. The study is conducted under three changing conditions of draft, such as even-keel, rise of the gravity center and trim to stern. Variables affecting berthing stability are determined based on the control performance of each condition. Bond graphs method is used to model the system. Controller is designed as PID control method of reference-model algorithm. The control program is composed of synchronous control system based on the equations derived with the numerical analysis. The tank test is conducted to verify the usefulness of the control program. 相似文献
862.
Tabish U. Ansari N. Ojha R. Chandrasekar C. Balaji Narendra Singh Sachin S. Gunthe 《Journal of Atmospheric Chemistry》2016,73(4):363-380
The spatial distribution of trace gases exhibit large spatial heterogeneity over the Indian region with an elevated pollution loading over densely populated Gangetic Plains (IGP). The contending role and importance of anthropogenic emissions and meteorology in deciding the trace gases level and distribution over Indian region, however, is poorly investigated. In this paper, we use an online regional chemistry transport model (WRF/Chem) to simulate the spatial distribution of trace gases over Indian region during one representative month of only three meteorological seasons namely winter, spring/summer and monsoon. The base simulation, using anthropogenic emissions from SEAC4RS inventory, is used to simulate the general meteorological conditions and the realistic spatial distribution of trace gases. A sensitivity simulation is conducted after removing the spatial heterogeneity in the anthropogenic emissions, i.e., with spatially uniform emissions to decouple the role of anthropogenic emissions and meteorology and their role in controlling the distribution of trace gases over India. The concentration levels of Ozone, CO, SO2 and NO2 were found to be lower over IGP when the emissions are uniform over India. A comparison of the base run with the sensitivity run highlights that meteorology plays a dominant role in controlling the spatial distribution of relatively longer-lived species like CO and secondary species like Ozone while short-lived species like NOX and SO2 are predominantly controlled by the spatial variability in anthropogenic emissions over the Indian region. 相似文献
863.
Prof. F. S. Zanon 《Pure and Applied Geophysics》1952,22(1-2):97-107
Riassunto Si conferma, con un nuovo settennio di osservazioni, il valore già altre volte determinato dall'A. dellatemperatura critica di antèsi per ilTaxus baccata. E con un ventennio di osservazioni si determina il valore dell'analogo elemento biologico per ilPunica granatum.
Summary We confirm with a new septennium of observations the value that has been already other times determined by the author of the critical temperature of antèsi for the Taxus baccata and with a period of twenty years of observations we determine the value of the analogous biologic element for the Punica granatum.相似文献
864.
A. A. Cheremisin P. V. Novikov I. S. Shnipov V. V. Bychkov B. M. Shevtsov 《Geomagnetism and Aeronomy》2012,52(5):653-663
Lidar observations during 2007–2008 in Kamchatka revealed aerosol layers in the upper stratosphere at heights of 35–50 km and in the mesosphere at heights of 60–75 km. It is well known that forces of gas-kinetic nature, i.e., photophoretic forces, act on aerosol particles that absorb solar radiation and terrestrial IR radiation; these forces can counteract the gravitational force and even lead to the levitation of these particles at particular heights. The accumulation of particles at these heights may lead to the formation of aerosol layers. We calculated these forces for the conditions of lidar observations in Kamchatka. Aerosol layers were observed at heights where particle levitation can occur. Thus, the stratospheric and mesospheric aerosol layers, detected at heights of 30–50 and 60–75 km, respectively, may be due to the effect of the photophoretic force on aerosol particles. 相似文献
865.
Rens J. H. Masselink Tobias Heckmann Arnaud J. A. M. Temme Niels S. Anders Harm P. A. Gooren Saskia D. Keesstra 《水文研究》2017,31(1):207-220
Hydrological connectivity describes the physical coupling (linkages) of different elements within a landscape regarding (sub‐) surface flows. A firm understanding of hydrological connectivity is important for catchment management applications, for example, habitat and species protection, and for flood resistance and resilience improvement. Thinking about (geomorphological) systems as networks can lead to new insights, which has also been recognized within the scientific community, seeing the recent increase in the use of network (graph) theory within the geosciences. Network theory supports the analysis and understanding of complex systems by providing data structures for modelling objects and their linkages, and a versatile toolbox to quantitatively appraise network structure and properties. The objective of this study was to characterize and quantify overland flow connectivity dynamics on hillslopes in a humid sub‐Mediterranean environment by using a combination of high‐resolution digital‐terrain models, overland flow sensors and a network approach. Results showed that there are significant differences between overland flow connectivity on agricultural areas and semi‐natural shrubs areas. Significant positive correlations between connectivity and precipitation characteristics were found. Significant negative correlations between connectivity and soil moisture were found, most likely because of soil water repellency and/or soil surface crusting. The combination of structural networks and dynamic networks for determining potential connectivity and actual connectivity proved a powerful tool for analysing overland flow connectivity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
866.
In this letter we develop a new concept, the negative alpha filter, which we suggest has application for quantitative estimation of surface parameters beneath vegetation using polarimetric synthetic aperture radar (SAR) interferometry (POLInSAR). We first derive the filter and then validate it using simulations of L-band coherent forest scattering. We then show initial results of applying the filter to airborne data from the German Aerospace Center's E-SAR L-band sensor. 相似文献
867.
We have obtained Bianchi type-III cosmological model with strange quark matter attached to the string cloud in general relativity.
For solving the Einstein’s field equations the relation [C=A
n
] between metric coefficients C and A is used. Also, some physical and kinematic properties of the model are discussed.The results are analogous to results obtained
by Yilmaz (Gen. Rel. Grav. 38:1397–1406, 2006). 相似文献
868.
869.
In this paper the probability of green water occurrence is investigated by taking into account the threshold of the vertical relative motion exceeding the freeboard. The number of wetting of the unit/vessel is predicted using probabilistic method. This paper compares the significant load, due to shipping of green water with the works of other researchers, and the loads are found to be close with the results presented in this paper. There is no direct relation between the velocities in the waves and the water velocity over the deck. The water velocities around the bow are heavily distributed by the presence of the bow. This scenario makes the flow very complex for schematic modelling. 相似文献
870.
Christine S McCulloch 《Area》2006,38(1):24-33
Public participation in transparent decisionmaking has been proposed as a panacea for environmental protection. Bargaining theory suggests drawbacks to transparency such as hardening of attitudes and intransigence. Yet achievement of consensus on environmental values for integrated water resource management demands public involvement. Historical study of attempts to prevent reservoir construction in upland valleys designated for protection of nature suggests that 'closed-door' bargaining proved more effective for environmentalists than open, public debate. Records now open for analysis of disputes over Teesdale and Farndale, 1950–1970, allow comparisons to be made between behind-the-scenes deliberations and 'open-door' public discussion. The ambition of progressing from public participation to devolution of environmental decisionmaking and responsibility to the local scale demands more conceptualization of the process of decisionmaking on water resource development. 相似文献