Toward the Development of Load Transfer Efficiency Evaluation of Rigid Pavements by a Rolling Wheel Deflectometer

The jointed rigid pavement is currently evaluated by the Falling weight deflectometer which is rather slow for the testing of the jointed pavements. Continuous nondestructive evaluation of rigid pavements with a rolling wheel deflectometer can be used to measure the load transfer and is investigated. Load transfer is an important indicator of the rigid pavement's condition and this is the primary factor which is studied. Continuous data from experimental measurements across a joint allows for the determination of not only the load transfer efficiency provided parameters characterizing the pavement is known. A three-dimensional semi-analytical model was implemented for simulating the pavement response near a joint and used for interpretation and verification of the experimental data. Results show that this development is promising for the use of a rolling wheel deflectometer for rapid evaluation of joints

Lighting and Energy Performance of an Adaptive Shading and Daylighting System for Arid Climates

Finding the proper trade-off between blocking direct sunlight, ensuring sufficient indoor daylighting and view out is a particularly delicate task especially in arid climates, due to harsh environmental conditions. As a tentative answer to this challenge, an adaptive shading and daylighting system (Shape Variable Mashrabiya – SVM) has been developed by the authors, described in an earlier paper. In this paper, we analyze how the SVM may affect annual lighting and global primary energy performance of an office building in Abu Dhabi: the SVM was applied to east and west façades and compared to external Venetian blinds, reflective and selective glazing

Time scales involved in market emergence

In addressing the question of the time scales characteristic for the market formation, we analyze high frequency tick-by-tick data from the NYSE and from the German market. By using returns on various time scales ranging from seconds or minutes up to two days, we compare magnitude of the largest eigenvalue of the correlation matrix for the same set of securities but for different time scales. For various sets of stocks of different capitalization (and the average trading frequency), we observe a significant elevation of the largest eigenvalue with increasing time scale. Our results from the correlation matrix study go in parallel with the so-called Epps effect. There is no unique explanation of this effect and it seems that many different factors play a role here. One of such factors is randomness in transaction moments for different stocks. Another interesting conclusion to be drawn from our results is that in the contemporary markets the emergence of significant correlations occurs on time scales much smaller than in the more distant history.Comment: 13 page

Evaluation of Load transfer in rigid pavements by Rolling wheel deflectometer and Falling weight deflectometer

Rigid pavements have widespread use, e.g, in motorways and airports, due to their excellent properties such as high bearing capacity and long lifetime. However, when rigid pavements fail it is often due to bad load transfer efficiency (LTE) at its joints. Traditional methods of measuring LTE can be time consuming. Here, we study the possibility of measuring LTE using a moving load with the aim of achieving higher productivity. An experiment simulating Rolling Weight Deflectometer (RWD) measurements on a joint was carried out to gain understanding and confidence that can guide the analysis of real RWD data. Continuous data from measurements across a joint allows for determination of not only the LTE but also additional parameters characterizing the pavement and the joint. A semi-analytical model was implemented for simulating the pavement response next to a joint and used for interpretation and verification of the experimental data. The results show promise for the use of moving loads for rapid evaluation of joints

Intraday Patterns in the Cross-section of Stock Returns

Motivated by the literature on investment flows and optimal trading, we examine intraday predictability in the cross-section of stock returns. We find a striking pattern of return continuation at half-hour intervals that are exact multiples of a trading day, and this effect lasts for at least 40 trading days. Volume, order imbalance, volatility, and bid-ask spreads exhibit similar patterns, but do not explain the return patterns. We also show that short-term return reversal is driven by temporary liquidity imbalances lasting less than an hour and bid-ask bounce. Timing trades can reduce execution costs by the equivalent of the effective spread

Decomposing Intraday Dependence in Currency Markets: Evidence from the AUD/USD Spot Market

The local Hurst exponent, a measure employed to detect the presence of dependence in a time series, may also be used to investigate the source of intraday variation observed in the returns in foreign exchange markets. Given that changes in the local Hurst exponent may be due to either a time-varying range, or standard deviation, or both of these simultaneously, values for the range, standard deviation and local Hurst exponent are recorded and analyzed separately. To illustrate this approach, a high-frequency data set of the spot Australian dollar/U.S. dollar provides evidence of the returns distribution across the 24-hour trading day with time-varying dependence and volatility clearly aligning with the opening and closing of markets. This variation is attributed to the effects of liquidity and the price-discovery actions of dealers.Comment: 3 Figures, 3 Tables, 28 page

Model Channel Ion Currents in NaCl - SPC/E Solution with Applied-Field Molecular Dynamics

Using periodic boundary conditions and a constant applied field, we have simulated current flow through an 8.125 Angstrom internal diameter, rigid, atomistic channel with polar walls in a rigid membrane using explicit ions and SPC/E water. Channel and bath currents were computed from ten 10-ns trajectories for each of 10 different conditions of concentration and applied voltage. An electric field was applied uniformly throughout the system to all mobile atoms. On average, the resultant net electric field falls primarily across the membrane channel, as expected for two conductive baths separated by a membrane capacitance. The channel is rarely occupied by more than one ion. Current-voltage relations are concentration-dependent and superlinear at high concentrations.Comment: Accepted for publication in Biophysical Journa

Anticipatory freight selection in intermodal long-haul round-trips

We consider the planning problem faced by Logistic Service Providers (LSPs) transporting freights periodically, using long-haul round-trips. In each round-trip, freights are delivered and picked up at different locations within one region. Freights have time-windows and become known gradually over time. Using probabilistic knowledge about future freights, the LSP’s objective is to minimize costs over a multi-period horizon. We propose a look-ahead planning method using Approximate Dynamic Programming. Experiments show that our approach reduces costs up to 25.5% compared to a single-period optimization approach. We provide managerial insights for several intermodal long-haul round-trips settings and provide directions for further research