Effect of casting method on castability of titanium and dental alloys

Titanium, once considered to be difficult to cast because of its relatively high melting point and strong chemical affinity, can now be acceptably cast using newly developed casting apparatus. The objectives of this study were to examine the castability of commercially pure (CP) titanium using an ultra high-speed centrifugal casting machine and a pressure difference-type casting unit and to compare the castability of titanium with that of conventional dental casting alloys. To determine castability, two types of patterns were used: a mesh pattern of 22 × 24 mm cut polyether thread sieve, and a saucer pattern (24 mm diameter) perforated to create four T-shaped ends. The casting equipment significantly affected the mold filling of both patterns . The castability indices obtained from both patterns of CP titanium cast in the centrifugal casting machine were significantly better than the indices of the castings produced in the pressure-difference casting unit. The radiographs of the saucer pattern cast in the centrifugal casting machine showed some pores that were fewer and smaller in size than the pores found in castings made in the pressure-difference unit. When the ultra high-speed centrifugal casting machine was used with the manufacturers recommended mold material, the castability of titanium was similar to that of gold alloy or Ni-Cr alloy cast by conventional means.     

Effect of Pd and In on mercury evaporation from amalgams

The aim of work was evaluation of voice pathology in patients with allergic rhinitis. Larynx organic pathology were found in 75% patients with coexisting allergic rhinitis in the form of Reinke's oedema, chronic hypertrophic laryngitis, larynx polyp and vocal nodules. It caused serious voice pathology (dysphonia) which was confirmed by an objective spectrographic method. Larynx organic pathology was not in 15% patients. In these cases rhinophonia was found in consequence of resonance nasal defect.     

Electrochemical reduction of CO2: Two- or three-electrode configuration

Electrocatalytical conversion of CO₂ into various chemicals like hydrocarbons and CO is regarded as a promising approach to mitigate carbon emission and, meanwhile, to provide sustainable energy and value-added chemicals. Two different reactors are used in this work. One is based upon the two-electrode configuration powered by a DC power supply or Si solar cell, which is suitable for practical applications. Another is three-electrode one powered by a potentiostat, which is feasible to study the electrode performance. Polycrystalline Cu electrode is used as the cathode, and hematite is the anode. Performance of CO₂ reduction using the two- and three-electrode configurations is studied by measuring electrode potential, cell voltage, current density, Faradaic efficiency, and reduction selectivity of CO₂. Cu cathode used here exhibits a low overpotential for CO₂ reduction, specifically for the cell with two-electrode configuration. No obvious difference can be observed between the two types of configurations at a low bias like −0.3 and −0.4 V; while the reactor with two-electrode configuration exhibits better performance at a high bias like −0.8 V than the one with three-electrode configuration. Thus, the reactors with two-electrode configuration are desirable for practical applications, specifically considering solar cells can be used as the power source to provide green and sustainable energy.     

Automated purification of dye terminator sequencing reactions: an approach to high-throughput capillary electrophoresis sequencing of large templates

Demands for higher quantity and quality of sequence data during genome sequencing projects have led to a need for completely automated reagent systems designed to isolate, process, and analyze DNA samples. While much attention has been given to methodologies aimed at increasing the throughput of sample preparation and reaction setup, purification of the products of sequencing reactions has received less scrutiny despite the profound influence that purification has on sequence quality. Commonly used and commercially available sequencing reaction cleanup methods are not optimal for purifying sequencing reactions generated from larger templates, including bacterial artificial chromosomes (BACs) and those generated by rolling circle amplification. Theoretically, these methods would not remove the original template since they only exclude small molecules and retain large molecules in the sample. If the large template remains in the purified sample, it could understandably interfere with electrokinetic injection and capillary performance. We demonstrate that the use of MagneSil^® paramagnetic particles (PMPs) to purify ABI PRISM^® BigDye^® sequencing reactions increases the quality and read length of sequences from large templates. The high-quality sequence data obtained by our procedure is independent of the size of template DNA used and can be completely automated on a variety of automated platforms.     

Application of a spatial decision support system (SDSS) to reduce soil erosion in northern Ethiopia

A spatial decision support system (SDSS) based on multi-criteria and multi-objective decision analysis is applied in a case study in Ethiopia to reduce soil erosion on the basis of reallocation of crops according to their capacity to protect the soil. The case study is carried out in the Adwa district. The SDSS has been implemented using the widespread GIS software IDRISI 32 (release 2) and with the direct involvement of local stakeholders in defining factors and constraints. These are based on land cover-land use, altitude, potential erosion, proximity to roads, water and the relative soil protective capacity of each crop species. A reduction of soil loss from an average of 4.5 t ha⁻¹ yr⁻¹ to values below the risk threshold of soil degradation (1 t ha⁻¹ yr⁻¹) would be achieved through the application of the SDSS results. The biggest impediment to the reallocation exercise, however, is the shortage of cultivable land suitable for cultivation.     

Estimating sediment yield risk of reservoirs in northern Ethiopia using expert knowledge and semi‐quantitative approaches

Reservoir siltation is a serious problem that threatens the productivity and sustainability of water‐harvesting schemes. Quantification of sediment deposition in reservoirs and understanding of its major drivers are needed to apply targeted management interventions. Most of the techniques used to estimate sediment deposition in reservoirs require extensive measurements on a frequent time basis, as well as being costly and time‐consuming. Thus, a rapid and relatively economical means of assessing the erosion susceptibility of catchments and predicting their sediment yield potential is necessary. In this study, expert‐based rankings and semi‐quantitative factorial scoring approaches were applied to assess the siltation severity of 25 reservoirs in the Tigray region of northern Ethiopia. The results were then correlated with quantitative sediment yield estimates acquired for representative sites, and a sediment yield predication model was developed for the region. The calibrated model has an efficiency and relative root mean square error (RRMSE) of 79 and 36%, respectively, which is considered adequate to assess erosion susceptibility and siltation risk of reservoirs in similar environments. The study demonstrates that expert knowledge and rapid characterization of catchments, in terms of susceptibility to erosion, are viable options for assessing siltation risks and for analysing controlling factors at a larger number of sites, with minimum costs and acceptable accuracy.