The analysis of heuristics for search trees

We analyze the performance of search trees built under a variety of insertion heuristics. The main results are a method to obtain asymptotic expressions for the moments of the distribution of the search time, and a proof that this distribution is asymptotically normal.     

The use of seawater as process water at Las Luces copper-molybdenum beneficiation plant in Taltal (Chile)

Las Luces is a copper-molybdenum beneficiation plant in Taltal (Chile), owned by the Las Cenizas Mining Group (Grupo Minero Las Cenizas) of Chile. The plant comprised of conventional crushing, grinding and flotation facilities. Las Luces has treated 720,000 tpa ore since 1995. This ore was supplied from Las Cenizas’ own underground mines operating in the area.Seawater is brought to the plant from a distance of 7 km and pumped to an altitude of 178 m. In the Las Luces plant, seawater is mixed with tailings dam water in the Industrial Storage Pond. The mixed water is used in the grinding and flotation circuits. The Las Luces beneficiation plant has been successfully using seawater for over 15 years through a clever water recirculation scheme. The Las Luces plant is unusual in the sense that it has operated during this time without the use of any fresh water.Analytical data show that the dissolved salt content of the process water has increased from 36.0 g/L to 46.4 g/L or 0.7 g/L/year. Calculations suggest that this increase is largely due to solar evaporation where the evaporation rate reaches 50 m³/hectare/day.In Las Luces, the evaporation related water losses amount to 237 megalitres/year or a loss of approximately 69 days of seawater pumping to the Industrial Storage Pond. Based on this finding Las Cenizas is now investigating options to minimise the loss of water to evaporation.     

Cross cultural analysis of the use and perceptions of web Based learning systems

The main objective of this paper is to examine cultural differences and technology acceptances from students of two universities, one is from a European country: Spain, and the other is in Latin America: Chile. Both of them provide their students with e-learning platforms. The technology acceptance model (TAM) and Hofstede’s cultural dimensions are the tools used to measure the acceptance and use of web-based learning platforms and cultural diversity of respondents, respectively. In summary, we can affirm that the sample of tertiary Spanish and Chilean students are culturally different with regard to some of Hofstede’s dimensions, but their behavior of acceptance of e-learning technology globally matches according to the TAM model. This study provides relevant implications for on-line courses managers’ who have tertiary students from different nationalities.     

Fuzzy region assignment for visual tracking

In this work we propose a new approach based on fuzzy concepts and heuristic reasoning to deal with the visual data association problem in real time, considering the particular conditions of the visual data segmented from images, and the integration of higher-level information in the tracking process such as trajectory smoothness, consistency of information, and protection against predictable interactions such as overlap/occlusion, etc. The objects’ features are estimated from the segmented images using a Bayesian formulation, and the regions assigned to update the tracks are computed through a fuzzy system to integrate all the information. The algorithm is scalable, requiring linear computing resources with respect to the complexity of scenarios, and shows competitive performance with respect to other classical methods in which the number of evaluated alternatives grows exponentially with the number of objects.     

Bench-Scale and Pilot-Scale Treatment Technologies for the Removal of Total Dissolved Solids from Coal Mine Water: A Review

Coal mine water (CMW) is typically treated to remove suspended solids, acidity, and soluble metals, but high concentrations of total dissolved solids (TDS) have been reported to impact the environment at several CMW discharge points. Consequently, various states have established TDS wastewater regulations and the US EPA has proposed a benchmark conductivity limit to reduce TDS impacts in streams near mining sites. Traditional CMW treatment effectively removes some TDS components, but is not effective in removing major salt ions due to their higher solubility. This paper describes the basic principles, effectiveness, advantages, and disadvantages of various TDS removal technologies (adsorption, bioremediation, capacitive deionization, desalination, distillation, electrochemical ion exchange, electrocoagulation, electrodialysis, ion exchange, membrane filtration, precipitation, and reverse osmosis) that have at least been tested in bench- and pilot-scale experiments.     

Energy storage unit: Solid state demonstrators at 20 K and 6 K

Cryocoolers’ vibrations prevent them from being used in some sensitive applications. Stopping the cryocooler even for a short period gives rise to a steep drift of temperature. Such a drift can be significantly attenuated by adding an enthalpy reservoir to the cryocooler, separated from its cold finger by a heat switch. The whole assembly for the enthalpy reservoirs and switch is here called ESU, the energy storage unit. Two units have been built and tested based on solid state materials. One unit was designed to work up to 20 K, the other up to 6 K. This paper presents the experimental results obtained for both ESUs.Lead was used for the 20 K ESU while the ceramic GOS (Gd₂O₂S) was found adequate for the 6 K ESU. After stopping the cryocooler, a fairly slow temperature drift was measured at each ESU (from 11 to 20 K or from 3 to 6 K, respectively) while applying 10 mW for one hour, for instance. Otherwise, a temperature controlled platform experiment can use an ESU as a cold source allowing a constant temperature. Input power to the ESUs was monitored along with temperature and time. In the case of the 20 K ESU, calculations match the stored amount of energy as well as the temperature drift of the energy reservoir.A study for a high enthalpy intercept at the middle of the switch is also presented here. This intercept shall allow the attenuated temperature drift to hold for longer times. A cryogenic experiment can then be carried on using a cryocooler in a completely silent environment.     

Fluorescence from the maillard reaction and its potential applications in food science

The chemistry of the Maillard reaction involves a complex set of steps, and its interpretation represents a challenge in basic and applied aspects of Food Science. Fluorescent compounds have been recognized as important early markers of the reaction in food products since 1942. However, the recent advances in the characterization of fluorophores' development were observed in biological and biomedical areas. The in vivo non-enzymatic glycosylation of proteins produces biological effects, promoting health deterioration. The characteristic fluorescence of advanced glycosylation end products (AGEs) is similar to that of Maillard food products and represents an indicator of the level of AGE-modified proteins, but the structure of the fluorescent groups is, typically, unknown. Application of fluorescence measurement is considered a potential tool for addressing key problems of food deterioration as an early marker or index of the damage of biomolecules. Fluorophores may be precursors of the brown pigments and/or end products. A general scheme of the Maillard reaction is proposed in this article, incorporating the pool concept. A correct interpretation of the effect of environmental and compositional conditions and their influences on the reaction kinetics may help to define the meaning of fluorescence development for each particular system.