Amplification Effects of Soil Stratification on Ground Stress Waves

An analytical model is presented for the prediction of the amplification of compressional and shear waves produced by an explosion, or any other shock impact on the surface of a stratified soil deposit. This amplification is caused by multiple reflections of waves between the ground surface and an underlying parallel soil layer possessing different density and seismic velocity. The model developed may be easily applied for the protection of both buried and aboveground structures with the aid of suitable diagrams prepared in this work, which give, in a simple way, the enhancement factors by which particle velocities of direct waves should be multiplied to estimate the resultant particle velocities. The soil parameters that are taken into account in the analytical model and its simplified graphical solution are density, attenuation factor, and compressional- and shear-wave propagation velocities for the first two soil layers. Other parameters encountered are depth of the top soil layer, depth of burial of the structure, horizontal distance of the structure from the source, and trinitrotoluene equivalent of the source. The cube root scaling is considered for the attenuation of waves in soil with distance.     

On the properties of an additive increase rate accelerator

We propose AIRA, an Additive Increase Rate Accelerator. AIRA extends AIMD functionality towards adaptive increase rates, depending on the level of network contention and bandwidth availability. In this context, acceleration grows when resource availability is detected by goodput/throughput measurements and slows down when increased throughput does not translate into increased goodput as well. Thus, the gap between throughput and goodput determines the behavior of the rate accelerator.We study the properties of the extended model and propose, based on analysis and simulation, appropriate rate decrease and increase rules. Furthermore, we study conditional rules to guarantee operational success even in the presence of symptomatic, extra-ordinary events. We show that analytical rules can be derived for accelerating, either positively or negatively, the increase rate of AIMD in accordance with network dynamics. Indeed, we find that the “blind”, fixed Additive Increase rule can become an obstacle for the performance of TCP, especially when contention increases. Instead, sophisticated, contention-aware additive increase rates may preserve system stability and reduce retransmission effort, without reducing the goodput performance of TCP.     

Pre-treatment and ethanol fermentation potential of olive pulp at different dry matter concentrations

Renewable energy sources have received increased interest from the international community with biomass being one of the oldest and the most promising ones. In the concept of exploitation of agro-industrial residues, the present study investigates the pre-treatment and ethanol fermentation potential of the olive pulp, which is the semi solid residue generated from the two-phase processing of the olives for olive oil production. Wet oxidation and enzymatic hydrolysis have been applied aiming at the enhancement of carbohydrates' bioavailability. Different concentrations of enzymes and enzymatic durations have been tested. Both wet oxidation and enzymic treatment were evaluated based on the ethanol obtained in a subsequent fermentation step by Saccharomyces cerevisiae and Thermoanaerobacter mathranii. It was found that a four-day hydrolysis time was adequate for a satisfactory release of glucose and xylose. The combination of wet oxidation and enzymatic hydrolysis resulted in the glucose and xylose concentration increase of 138 and 444%, respectively, compared to 33 and 15% with only enzymes added. However, the highest ethanol production was obtained when only enzymic pre-treatment was applied, implying that wet oxidation is not a recommended pre-treatment process for olive pulp at the conditions tested. It was also showed that increased dry matter concentration did not have a negative effect on the release of sugars, indicating that the cellulose and xylan content of the olive pulp is relatively easily available. The results of the experiments in batch processes clearly emphasize that the simultaneous saccharification and fermentation (SSF) mode is advantageous in comparison with the separate hydrolysis and fermentation (SHF) mode concerning process contamination.     

Edge postprocessing using probabilistic relaxation

In this paper, we develop the theory of probabilistic relaxation when the objects to be labeled are arranged in a rectangular grid with known adjacency relations. In this case a dictionary of permissible label configurations is available. The novelty of this work lies in the inclusion of measurements concerning binary relations between the objects to be labeled. These are compared with the corresponding binary relations between the nodes of the dictionary. This way, one of the major objections to probabilistic relaxation, namely, the disregard of the data after the initial assignment of probabilities, is removed. The theory we develop is demonstrated by applying it to the problem of edge relaxation labeling. We show that the inclusion of binary relations greatly improves the performance of algorithms of this kind and compare our approach with previously developed dictionary based approaches, both theoretically and experimentally. Also, a comparison with other edge-postprocessing strategies is provided.     

Chaotic analysis of US money and velocity measures

This paper uses tools from dynamical systems theory to investigate the properties of US money and velocity series. Comparisons are made between simple-sum, Divisia and currency equivalent aggregates (of M1, M2, M3, and L), using the Anderson et al. monthly data (from January 1960 to June 1996).     

Comparative study of vision tracking methods for tracking of construction site resources

Vision tracking has significant potential for tracking resources on large scale, congested construction sites, where a small number of cameras strategically placed around the site could replace hundreds of tracking tags. The correlation of vision tracking 2D positions from multiple views can provide the 3D position. However, there are many 2D vision trackers available in the literature, and little information is available on which one is most effective for construction applications. In this paper, a comparative study of various vision tracker categories is carried out, to identify which one is most effective in tracking construction resources. Testing parameters for evaluating categories of trackers are identified, and benefits and limitations of each category are presented. The most promising trackers are tested using a database of construction operations videos. The results indicate the effectiveness of each tracker in relation to each parameter of the test, and the most suitable tracker needed to research effective 3D vision trackers of construction resources.     

Setting process of lime-based conservation mortars with barium hydroxide

This paper presents the effect of barium hydroxide on the setting mechanism of lime-based conservation mortars, when used as an additive material. The study focuses on the monitoring of the setting process and the identification of the mineral phases formed, which are essential for furthering the study of the durability of barium mixtures against chemical degradation. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and thermal analysis (DTA-TG) were used to monitor the setting processes of these mixtures and identify new phases formed. The results suggest that barium hydroxide is evenly distributed within the lime and produces a homogeneous binding material, consisting of calcite (CaCO₃), witherite (BaCO₃) and barium-calcium carbonate [BaCa(CO₃)₂]. Finally, it was found that barium carbonate can be directly bonded to calcitic aggregates and therefore increases its chemical compatibility with the binding material.     

Spoilage potential of ice-stored whole musky octopus (Eledone moschata)

The spoilage potential of fresh musky octopus ( Eledone moschata ) was determined by evaluating the changes in biochemical and physical properties, microbial growth and sensory quality of the mantle and tentacles, over a period of 18 days. Whole musky octopus, stored in melting ice from the time of harvest, had a storage life of 10 days. Early deterioration in the sensory quality resulted primarily from autolytic reactions. Pseudomonas spp. dominated the spoilage flora, reaching an average count of 10⁸ CFU g⁻¹ at the end of the trial. The bacterial metabolic end products (trimethylamine, total volatile bases) were not useful as objective indicators of freshness, and measurements of pH would only provide an indicator of decomposition. Changes in the dielectric properties of the mantle were reflective of quality deterioration, but could not yield precise information on the storage history of the cephalopod. The common sulphide producer, Shewanella putrefaciens , was not a major spoiler of ice-stored musky octopus.