Revisión. Los problemas de la contaminación en la industria metalúrgica.

The mineral processing and metal production have increased significantly in recent years. As a result, the amounts of waste materials and pollutants are also increasing. In many cases, technology has changed to address the problem. The processes have been modified to either reduce emissions, or replaced by others that are less polluting, albeit at a higher cost. Are briefly presented, examples of ferrous and non-ferrous industries.El procesamiento de minerales y la producción de metales han aumentado considerablemente en los últimos años. Como resultado, las cantidades de material de desecho y contaminantes también han aumentando. En muchos casos, la tecnología ha cambiado para hacer frente al problema. Los procesos han sido ya sea modificada para disminuir las emisiones, o sustituidas por otras que son menos contaminantes, aunque a un costo mayor. Se presentan brevemente, ejemplos de las industrias ferrosos y no ferrosos

Trajectory-based Human Action Recognition

Human activity recognition has been a hot topic for some time. It has several challenges, which makes this task hard and exciting for research. The sparse representation became more popular during the past decade or so. Sparse representation methods represent a video by a set of independent features. The features used in the literature are usually lowlevel features. Trajectories, as middle-level features, capture the motion of the scene, which is discriminant in most cases. Trajectories have also been proven useful for aligning small neighborhoods, before calculating the traditional descriptors. In fact, the trajectory aligned descriptors show better discriminant power than the trajectory shape descriptors proposed in the literature. However, trajectories have not been investigated thoroughly, and their full potential has not been put to the test before this work. This thesis examines trajectories, defined better trajectory shape descriptors and finally it augmented trajectories with disparity information. This thesis formally define three different trajectory extraction methods, namely interest point trajectories (IP), Lucas-Kanade based trajectories (LK), and Farnback optical flow based trajectories (FB). Their discriminant power for human activity recognition task is evaluated. Our tests reveal that LK and FB can produce similar reliable results, although the FB perform a little better in particular scenarios. These experiments demonstrate which method is suitable for the future tests. The thesis also proposes a better trajectory shape descriptor, which is a superset of existing descriptors in the literature. The examination reveals the superior discriminant power of this newly introduced descriptor. Finally, the thesis proposes a method to augment the trajectories with disparity information. Disparity information is relatively easy to extract from a stereo image, and they can capture the 3D structure of the scene. This is the first time that the disparity information fused with trajectories for human activity recognition. To test these ideas, a dataset of 27 activities performed by eleven actors is recorded and hand labelled. The tests demonstrate the discriminant power of trajectories. Namely, the proposed disparity-augmented trajectories improve the discriminant power of traditional dense trajectories by about 3.11%

The nature and frequency of marital problems which lead to divorce in Tehran, Iran : as perceived by four professional groups

The Problem. During the past several decades Iranian society has undergone substantial change. Industrialization, urbanization, and universal education have been dynamic forces in changing Iranian society. Such factors may have influenced the structure and function of the family in Iran. In addition, and perhaps related to these factors, other developments occurred. The bond of kinship began to weaken and the neighborhood changed due to a trend toward the nuclear family. The solidarity of tradition was loosened. This was especially true in Tehranian society. One important development from these changes was a more active role by women in the society. Women have been somewhat liberated from traditional restrictive practices through legislative and social development. Marriage and divorce are perhaps sensitive indices through which changes in family structure can be studied. In 1976, the ratio of divorce to marriage in Tehran was about one to three, which was the highest rate of divorce in the country since 1942 when record-keeping began. It was the intention of this study to ascertain the nature and frequency of marital problems which led to divorce in Tehran during the 1967-79 period as perceived by four different professional groups in Tehran. These problem areas were organized under three major aspects: (1) characteristics or behaviors of the wife, (2) characteristics or behaviors of the husband, and (3) general or miscellaneous factors. Procedures. The data for this descriptive study were collected by the questionnaire method from 120 randomly selected individuals of four different professional groups in Tehran. These four professional groups were: 30 practicing psychologists; 30 heads of notary public; 30 social workers; and 30 family court judges. All of these four professional groups were directly involved in some aspect of the divorce proceedings. Frequency and percentage distribution of responses to the questionnaire item were derived. These were accomplished for the composite of the four professional groups as well as for each professional group separately. Findings and Discussion. The findings of this study regarding sex behavior are consistent with those of other studies performed in Iran. Majority of the respondents considered having extra-marital relations to be detrimental to the marriage relationship for both husband and wife. Alcoholism and/or drug addiction and gambling were other problems which led to divorce. These problems previously were recognized as problems for the husband, but this study indicated that these problems are increasing among wives in Iran. The changing role of women and their participation in social life may have resulted in their involvement in alcoholism and gambling. Another cause of divorce was interference from in-laws. Iranian families, for the most part, live in extended family units. Several generations may live in the same city making frequent contact relatively easy. While such a relationship has some advantages, the tendency for in-laws to interfere in their offsprings lives can have a negative effect. Recommendation for Further Study. With regard to the information base obtained from these data and related research of the literature, the investigator recommends that further research be conducted in the following areas: (1) A replication of this study in other urban areas in different parts of Iran in an effort to substantiate the findings of the present study and extend the generalizations to a wider population; (2) A replication of this study in rural areas of Iran to investigate similarities and differences between urban and rural sources of marital discord

Desertification Assessment Using MEDALUS Method and GIS Techniques in North America Arid Environments

Desertification is a massive issue that affects many countries that have dry climates. The impacts of this phenomenon threaten the sustainability of natural resources, as well as agricultural, water, and food resources. Several factors that affect directly or indirectly desertification and making it worse are population growth, climate change, deforestation, overgrazing, natural disaster, and urbanization and other types of land development. This thesis research evaluated the desertification index in three counties in California State and three counties in New Mexico State by using the MEDALUS model (Mediterranean Desertification and Land Use) within a geographic information system (GIS). The model includes four indices that can affect desertification: soil quality, climate quality, vegetation quality, and management quality. For each quality index, several parameters were identified. For instance, soil quality index has five parameters that are slope, depth, organic matter, texture, and drainage. Each of these parameters is quantified according to MEDALUS method by giving them a sensitivity coefficient. Then the quality index obtained by combination of parameters. The final results, assessed with the proposed Land Desertification Sensitivity Index by using the MEDALUS method (based on 14 sub-indicators), showed that approximately 82% of the total study areas are critically sensitive to desertification, mainly due to aridity index, precipitation, fire risk, and land use in California counties, while in New Mexico the critical factors were organic matters, aridity index, precipitation, and land use. From the results it is clear that the MEDALUS method was appropriate to apply to study areas. In addition, this study suggests that the maps of ESAs can represent a valuable tool to promote and orientate effective policies of desertification mitigation and prevention

Towards real-time CFD simulation of in-flight icing

Despite the concerted efforts of manufacturers and certification agencies, incidents and accidents continue to happen to aircraft certificated to “Fly Into Known Icing”, falsely thought of as being “immune to in-flight icing”. The current successive process of CFD for ice shape prediction, then icing tunnel testing (experimental fluid dynamics- EFD), and finally flying in natural ice conditions (flight fluid dynamics-EFD), has many gaps that can only be filled by modern CFD. By developing compatible CFD tools able to simulate both the aerodynamics and icing in a concurrent engineering way, and by viewing the aircraft as a system and not as disjoint components, it will be shown how CFD, EFD and can be combined in a rigorous mathematical way to carry out a much faster, more complete and more thorough evaluation of the aircraft’s FIKI and result in a much safer aircraft. The Seminar will cover aspects of physical and mathematical modeling (impingement, accretion, de-icing, anti-icing, conjugate heat transfer, turbulence modeling), CFD (FEM, FVM, automatic mesh optimization) and the actual certification campaign of China’s first regional Jet, the ARJ21. The seminar will particularly focus on a reduced-order modeling (ROM) framework inching toward the calculation, via RANS, of the aerodynamics + water impingement + ice accretion + performance degradation, in real-time. The ROM methodology is based on Proper Orthogonal Decomposition, multi-dimensional interpolation and machine learning algorithms, along with an error driven iterative sampling method, to adaptively select an optimal set of snapshots. The methodology is applied for the first time to a “full aircraft” and to the “entire” icing certification envelope, providing invaluable additional data to the limited ones from icing tunnels or natural flight-testing. The level of accuracy achieved strongly supports the drive to incorporate more CFD information into in-flight icing certification and pilot training programs, leading to increased aviation safety

Characterization of Aluminum-Substituted Yttrium-Iron Garnet Nanoparticles Prepared Using the Sol-Gel Technique

This project presents preparation and characterization of aluminum substituted yttrium iron garnet (Al-YIG) nanocrystalline powders of compositional variation of Y3.0-xAlxFe5O12, where x was 0, 0.5, 1, 1.5, 2, 2.5 and 3. The samples were synthesized using sol–gel technique. The starting raw materials used to prepare Al-YIG samples were aluminum nitrate (Al(NO3)3.9H2O), yttrium nitrate (Y(NO3)3.6H2O) and iron nitrate (Fe(NO3)3.9H2O). They were weighed according to the formula above, then mixed and dissolved together in solution of citric acid (C6H8O7.H2O) for a month to form the gel form by using magnetic stirrer equipment at 350 r.p.m at room temperature. The sample was then dried at 110oC in an oven for a day to remove the unneeded water before it was calcined and crushed to obtain fine particles powder. The calcined powder at 600oC, 700oC, 800oC, 850oC and 900oC respectively, were characterized by x-ray diffraction analyzer (XRD) to confirm the garnet phase. All samples were characterized also by RF-Impedance (1 MHz-1.8 GHz) to investigate the magnetic properties. Finally, field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analyzer (EDX) were used to study the surface morphology and the elemental analysis of Al-YIG samples. The results showed that, the best garnet phase appeared when the sintering temperature was 800oC and Al-YIG nano-crystalline samples with high purity and sizes ranging from 20 to 100 nm were obtained. The magnetic measurement results of Al-YIG samples prepared by sol-gel method, gave high values of real permeability, the highest value of 5.29 was given by Y3Fe5O12 sample at about 80 MHz which was attributed to the large grain size, the highest magnetic permeability observed was due to easy movement of domain walls; and it shifted to the high frequency with increasing the amount of aluminum. The widest useful working frequency range appeared for Y3Fe5O12 sample and, also shifted to reach high range with increasing the concentration of aluminum

Electromagnetic Characterization Of Sm-Yig And Sm-Yig-Pvdf Composites Prepared Using Modified Conventional Mixing Oxide Technique

Samarium substituted-yttrium iron garnet (Sm-YIG) nanoparticles were fabricated via a modified conventional mixing oxides (MCMO) method according to the Y3-xSmxFe5O12 system (0 ≤ x ≤ 3). In this research, utilization of an organic compound (ethanol) and metal oxides in conjunction with mixing the reactants directly without adding water are the key techniques of this method. Using ethanol solution instead of water could produce nanoparticles with better homogeneity and smoother surface structure. Single-phase garnet structure of Sm-YIG nanoparticles was produced at 1350 0C sintering temperature with an average particle size ranged from 25 to 39 nm. XRD results of Sm-YIG samples at x = 2 and 2.5, presented some unknown peaks which speculated to, the time or/and sintering temperature is/are not enough to form the garnet structure phase of the samples. The true density values of 5.245 and 6.221 g.cm-3 were calculated for pure yttrium iron garnet (YIG, x=0) and samarium iron garnet (SmIG, x=3) samples, respectively which reached around 99% of the theoretical density of the samples. Real permittivities of the Sm-YIG samples presented almost flat values ranged from 7 to 10 with loss factors around 0.1 to 0.3, for YIG (x=0) and SmIG (x=3) respectively, within 10 MHz to 1 GHz frequency range. The real permeability value 19.5 is presented by pure YIG at 13.4 MHz and declined rapidly to be around 2 at 1 GHz, and decreased with increasing x. The higher permeability resulted in lower permittivity and vice versa for all the Sm-YIG samples. This work was also carried out to prepare the 10 wt% Sm-YIG in Poly-vinylidene-fluride (PVDF) composite samples and study their electromagnetic properties. Sm-YIG samples prepared via MCMO method, PVDF powder and Ethyl-methyl-ketone (MEK) were used to prepare such composites. High permittivities of composite samples observed at lower frequency range indicated to the heterogeneous conduction in the multiphase structure of the composites. The real permeabilities presented almost flat values through all the range of the frequency from 10 MHz to 1 GHz, with value of 1.06 at x=0 and 1.13 at x=3, for 10 wt% Sm-YIG loading in the composites. MCMO technique appears to be another alternative to the conventional (manufactured) technique, due to the decreasing of the particle size with better homogeneity, high purity, reduction of the cost, and high yield in a nano-scale product compared to other preparations techniques. The numerical optimization method performed using MATLAB program is to estimate the effective complex permittivity and/or permeability of each component of the 10 wt% Sm-YIG-PVDF composite samples. It is found that, the optimum impedance values are very close to the measured ones for each composite. The optimized values of the complex permittivities and permeabilities for both components [Sm-YIG and PVDF] are within the estimated ranges. The optimization process eliminated the difference between the measured impedance and the calculated one from Maxwell-Garnett (MG) formula via a specific objective function. Results of a developed formula based on MG formula with a comparison of various theoretical models including the MG, Looyenga, Bruggeman and Sen-Scala-Cohen, have been carried out and discussed with comparisons to the measurements for the 10 wt% Sm-YIG-PVDF composite samples. This was to calculate the complex permittivity and permeability of such composite materials. The lowest mean error percentage values were detected from the developed MG formula for each composite, which was different from composite to composite depend on the mole fraction x. The developed MG model appears to add a new contribution to the theoretical models to calculate the effective permittivity and permeability of mixture ferrite-polymer materials, due to its accuracy as compared with others

The preparation of ultra fine beryllium powder by the amalgam process Technical report

Beryllium powder production by electrolysis of beryllium chloride-sodium chloride molten eutectic mixtur