Milk Price Volatility and its Determinants

The classified pricing of fluid milk under the Federal Milk Marketing Orders (FMMO) system combined with the cash settlement feature of Class IIII milk futures contracts generate a unique volatility pattern of these futures markets in the sense that the volatility gradually decreases as the USDA price announcement dates approaching in the month. Focusing on the evolution of volatility in Class III milk futures market, this study quantifies the relative importance of a set of factors driving milk price variation. While volatilities in both corn futures market and financial market Granger-cause the milk price volatility, the impact of financial market is more persistent. Besides embedded seasonality, market demand and supply conditions in the dairy market, cheese in this case, as well as changes in the U.S. exchange rates are found to have positive and statistically significant impacts on milk price volatility. While speculation positively affects milk futures markets, the effect was found insignificant.Cash settlement, impulse responses, milk pricing, realized volatility, speculation, Agricultural and Food Policy, Q11, Q14.,

Deconfinement Phase Transition Heating and Thermal Evolution of Neutron Stars

The deconfinement phase transition will lead to the release of latent heat during spins down of neutron stars if the transition is the first-order one.We have investigated the thermal evolution of neutron stars undergoing such deconfinement phase transition. The results show that neutron stars may be heated to higher temperature.This feature could be particularly interesting for high temperature of low-magnetic field millisecond pulsar at late stage.Comment: 4 pages, to be published by American Institute of Physics, ed. D.Lai, X.D.Li and Y.F.Yuan, as the Proceedings of the conference Astrophysics of Compact Object

Influence of Central Siberian snow‐albedo feedback on the spring East Asian dust cycle and connection with the preceding winter Arctic oscillation

The Asian dust cycle has significant effects on the climate and environment, while its spatiotemporal variability and change mechanisms are not yet completely understood. Reanalysis data from the Modern‐Era Retrospective Analysis for Research and Applications, version 2 (MERRA2), data set are used to explore the spatiotemporal distribution of the East Asian dust cycle and possible reasons for the interannual variations. Based on the empirical orthogonal function analysis, the dominant mode of dust emissions from the East Asian deserts in the dust season (spring) shows that the Gobi Desert contributes most of the interannual variance of dust emissions in East Asia. The patterns of the regional circulation, temperature, and radiation are analyzed by regressing these variables against the principal component time series of the first empirical orthogonal function mode. The results show that the enhanced dust emissions are associated with a cyclonic circulation anomaly and cooling in the lower and middle troposphere over Central Siberia. The cooling is attributed to local snow‐albedo and cloud‐albedo feedbacks. The surface cooling is conducive to maintain the snow cover, whereas the cooling in the middle troposphere is associated with the increase of the relative humidity and cloud cover. The increased snow and cloud cover reflect more shortwave radiation, tending to maintain or amplify the surface cooling. It is also found that the negative phase of the Arctic Oscillation in winter initiates the surface cooling in the next spring and results in positive snow‐albedo and cloud feedbacks in Central Siberia, eventually enhancing the East Asian dust cycle

Intraseasonal variability of winter precipitation over Central Asia and the Western Tibetan plateau from 1979 to 2013 and its relationship with the North Atlantic Oscillation

Winter precipitation over Central Asia and the western Tibetan Plateau (CAWTP) is mainly a result of the interaction between the westerly circulation and the high mountains around the plateau. Empirical Orthogonal Functions (EOFs), Singular Value Decomposition (SVD), linear regression and composite analysis were used to analyze winter daily precipitation and other meteorological elements in this region from 1979 to 2013, in order to understand how interactions between the regional circulation and topography affect the intraseasonal variability in precipitation. The SVD analysis shows that the winter daily precipitation variability distribution is characterized by a dipole pattern with opposite signs over the northern Pamir Plateau and over the Karakoram Himalaya, similar to the second mode of EOF analysis. This dipole pattern of precipitation anomaly is associated with local anomalies in both the 700 hPa moisture transport and the 500 hPa geopotential height and is probably caused by oscillations in the regional and large-scale circulations, which can influence the westerly disturbance tracks and water vapor transport. The linear regression shows that the anomalous mid-tropospheric circulation over CAWTP corresponds to an anti-phase variation of the 500 hPa geopotential height anomalies over the southern and northern North Atlantic 10 days earlier (at 95% significance level), that bears a similarity to the North Atlantic Oscillation (NAO). The composite analysis reveals that the NAO impacts the downstream regions including CAWTP by controlling south-north two branches of the middle latitude westerly circulation around the Eurasian border. During the positive phases of the NAO, the northern branch of the westerly circulation goes around the northwest Tibetan Plateau, whereas the southern branch encounters the southwest Tibetan Plateau, which leads to reduced precipitation over the northern Pamir Plateau and increased precipitation over the Karakoram Himalaya, and vice versa

GROUND REACTON FORCE OF TABLE TENNIS PLAYERS WHEN USING FOREHAND ATTACK AND LOOP DRIVE TECHNIQUE

The subjects were 10 excellent ping-pong players in China. The table tennis techniques of the forehand attack and forehand loop drive were tested, using the measurement methods of the KISTLER force-plate system. The results showed that the biggest GRF of the attack technique in vertical direction was higher than the loop drive technique, and the biggest GRF of the attack technique in left-right direction and the fore-aft direction were mostly lower than the loop drive technique

Structural analysis of floating pipes of the fish cage in currents

A numerical model is developed to investigate the structural performance and stress distribution of floating pipes of fish cage subjected to the flow. The modeling approach is based on the joint use of the finite element method using the shell elements to simulate the floating pipes and the hydrodynamic force model improved from the Morison’s equation and lumped-mass method. The hydrodynamic response of the fish cage and forces on the floating pipes can be obtained by the Morison’s equation and lumped-mass method. The stress and deformation of the floating pipes can be evaluated using the finite element method. Using an appropriate iterative scheme, the stress distribution and maximum stress of the floating pipes can be obtained using the proposed model. To validate the numerical model, the numerical results were compared with the data obtained from corresponding physical model tests. The comparisons show the numerical results agree well with the experimental data. On that basis, the simulations of floating pipes in currents are performed to investigate the maximum stress and the critical locations. Simulations of the fish cage in different flow velocity are performed. The effect of the velocity on the deformations and stress of the floating pipes is analyzed. The simulations results show that the stress and deformations drastically increases with the increase of flow velocity. Comparing results of floating pipes with different mooring line arrangements indicates that increasing mooring lines can efficiently lower the stress of the floating pipes. The simulation of the SPM cage system with multiple net cages in current is preformed and the results show the middle cage is most dangerous for the tripartite-cage system

Numerical Research About the Internal Flow of Steam-jet Vacuum Pump: Evaluation of Turbulence Models and Determination of the Shock-mixing Layer

AbstractSteam-jet vacuum pump is widely used in a range of applications. This paper evaluated the performance of four well-known turbulence models for predicting and understanding the internal flow of a steam-jet vacuum pump first. With the help of a commercial computational fluid dynamics (CFD) code ANSYS-Fluent 6.3, the simulation results obtained from the concerned turbulence models were compared with experimental values, the k-omega-SST model was chosen as a tool model for carrying out numerical simulations. Then, based on the simulation results obtained from specific operating conditions, a method for locating the shock-mixing layer was put forward. The shape of the shock-mixing layer shows that the secondary steam does not mix with the primary steam immediately after being induced into the mixing chamber of the pump; actually, they maintain their independence till the shocking position instead. After the shock happens, the shock-mixing layer disappear, the two fluid in the pump begin to mix with each other and discharge to the next stage with almost the same state. Based on the shape of the shock-mixing layer and the supersonic region of the secondary steam, a detailed analysis for the flow duct of the secondary steam was carried out. It is found that the throat of the secondary steam flow duct plays a crucial role in maintaining a stable operating state and the length of the throat reflects the back pressure endurance for the pump