DEVELOPMENT OF THE OPTIMAL DESIGN OF A CYCLONE APPARATUS WITH A FLUIDIZED BED FOR THE PROCESS OF METALS PNEUMATIC SEPARATION IN THE COMPOSITION OF INDUSTRIAL WASTE

Recycling of techno genic waste accumulated in recent years in Uzbekistan is currently a pressing problem. In this regard, this paper examines the issue of studying the process of enrichment of man-made waste in a cyclone with a fluidized bed. To conduct the experiment on experimental advanced devices with extended zones five types of samples of techno genic waste with the limits of 0.072÷0.078mm, 0.064÷0.070mm, 0.057÷0.063mm, 0.046÷0.055mm and 0.041÷0.044mm have been prepared. Nomograms have been obtained using mathematical models to determine particle size limits, which ensure good separation. Experiments have been carried out on the separation of techno genic waste in three structures of a cyclone with a fluidized bed: cylindrical, cylindrical with one extended zone and cylindrical with two extended zones. The best results are obtained in a fluidized bed machine with one extended zone. The following results were obtained for a sample with a 0.041÷0.044 mm limit size: the number of Mo increased 40 times, Ag increased 20 times, Mn increased 2.5 times, Cu increased 1 time, Ti increased 6.6 times, Ni decreased 125 times and the number of Si in the selected sample decreased from 20% to 12%.

Occurrence of ESBLs in Clinical Isolates of Klebsiella Species and Comparative Analysis of Phenotypic Detection Methods

Aims: Drug resistance enzymes like beta-lactamases and Extended-Spectrum Beta- Lactamases (ESBLs) are mostly produced in the response of mutation and a few other factors. These enzymes are plasmid-mediated that can confer resistance against several β-lactam agents including cephalosporin and extended-spectrum cephalosporin. This study is conducted to determine the frequency of ESBL producing Klebsiella strains and to compare the phenotypic detection methods among various clinical samples collected from a commercial centralized Microbiology diagnostic laboratory. Materials and Methods: 125 Klebsiella strains were collected for this study. After identification and susceptibility testing, the phenotypic characterization of ESBL producing K. pneumoniae (n=89) and K. oxytoca (n=36) species was performed by using the double disc synergy test and the combination disc test. Results: In our study, 80 (64%) Klebsiella isolates were found to be ESBL positive due to their ability to produce an extended zone of inhibition with combination disc whereas 45 (36%) isolates were ESBL negative with no extended zone of inhibition. The phenotypic findings obtained by using the combination disc method and double disc synergy method were re-confirmed by molecular methods. By comparing the phenotypic finding with the genotypic results, we identified 80 (64%) Klebsiella isolates as ESBL positive and 45 (36%) isolates as ESBL negative. These genotypic findings of the ESBL producing strains were similar to the results obtained from the combination disc method. It also confirmed that the double disc synergy test was unable to detect 47 ESBL producing klebsiella strains. Conclusion: For implementing strict infection control policy and to stop the spread of resistant strains, it is important to detect ESBL producing isolates more rapidly. A suitable antimicrobial therapy can be started timely with the early detection of resistance enzymes either phenotypically or genotypically. It has been proved that the combination disc test can be used more reliably and preferably as compared to the double disc synergy test for the detection of ESBL enzymes produced by Klebsiella strains.

Comparative analysis of reinforced concrete tee beams reinforcement methods

Due to the increase in requirements for transport facilities, there is a need to strengthen them. The article is devoted to the analysis of reinforcement methods for load-bearing reinforced concrete structures of transport structures. The author notes in what period of the bridge’s life, it needs reinforcement, what difficulties are associated with reinforcing structures, and what are the main amplification methods that exist today. In order to select the optimal amplification method, it is necessary to carry out verification calculations, study the zone requiring amplification, take into account how many times the load-bearing capacity will increase and whether additional force effects will occur. This article describes the advantages and disadvantages of reinforcing by welding additional reinforcement and bonding composite material. The author calculated the amplification of the extended zone of the T-section reinforced concrete beam of the superstructure with additional reinforcement and composite materials. Based on the calculations made, recommendations have been put forward on the relevance of using one or another method of reinforcing the structure.

A cost-effective method for tranquility mapping using open environmental data

In this study, we propose a cost-effective method for tranquillity mapping using multi-criteria analysis and open geospatial data. We apply this method in an extended zone around a major Greek highway trespassing areas of high natural value. Composite criteria are developed through analytic functions and geostatistical methods to reflect either barriers or enablers of tranquillity. The results indicate that it is possible to identify tranquility zones which are spatially plausible. To verify the validity of the results, we calculate the Kappa coefficient (0.71) and the overall accuracy (80%) using preference data obtained from non-specialized photo-interpreters in a sample of places on Google Earth. We believe that this method can inform planning, especially in countries with a weak landscape policy.

Recalculation of Laboratory Tests with the Extended Zone Method

The Advanced Calculation Method given in EN 1992-1-2 is accepted by engineers and building authorities for the determination of the fire resistance of reinforced concrete structures. It has been developed originally for the recalculation of laboratory tests: the time of failure is calculated for a given layout of reinforcement. But in the structural analysis of concrete columns, the area of reinforcement has to be calculated for a desired fire resistance. Design methods and strategies, which are suitable for the design of concrete compression members, require constant material properties and strain limits, which are not given for the Advanced Calculation Method. Therefore Achenbach and Morgenthal have proposed an extension of the Zone Method by Hertz, suitable for the implementation in commercial design software. In this paper, this Extended Zone Method is used to recalculate laboratory tests to determine the accuracy of this method. A statistical analysis of the results is performed to evaluate the statistical key data of the Extended Zone Method.

Ice-shelf fracture due to viscoelastic flexure stress induced by fill/drain cycles of supraglacial lakes

Using a previously derived treatment of viscoelastic flexure of floating ice shelves, we simulated multiple years of evolution of a single, axisymmetric supraglacial lake when it is subjected to annual fill/drain cycles. Our viscoelastic treatment follows the assumptions of the well-known thin-beam and thin-plate analysis but, crucially, also covers power-law creep rheology. As the ice-shelf surface does not completely return to its un-flexed position after a 1-year fill/drain cycle, the lake basin deepens with each successive cycle. This deepening process is significantly amplified when lake-bottom ablation is taken into account. We evaluate the timescale over which a typical lake reaches a sufficient depth such that ice-shelf fracture can occur well beyond the lake itself in response to lake filling/drainage. We show that, although this is unlikely during one fill/drain cycle, fracture is possible after multiple years assuming surface meltwater availability is unlimited. This extended zone of potential fracture implies that flexural stresses in response to a single lake filling/drainage event can cause neighbouring lakes to drain, which, in turn, can cause lakes farther afield to drain. Such self-stimulating behaviour may have accounted for the sudden, widespread appearance of a fracture system that drove the Larsen B Ice Shelf to break-up in 2002.

How to Enhance Efficiency and Accuracy of the Over-Deterministic Method Used for Determination of the Coefficients of the Higher-Order Terms in Williams Expansion

Using higher-order terms of the Williams expansion is necessary for assessment of fracture behavior of quasi-brittle materials. Multi-parameter fracture mechanics enables more accurate determination of the stress/displacement field even in a larger distance from the crack tip, thus the extended zone with non-elastic behavior typical for this kind of material can be well described. The so-called over-deterministic method (ODM) seems to be a suitable tool for the higher-order terms coefficients calculation, but its utilization exhibits some limitations. Therefore, extensive analyses have been performed in order to summarize recommendations regarding the mesh sensitivity, boundary conditions influence, etc. List of pieces of advice and author’s experiences presented in the end of this work should contribute to more accurate and effective utilization of the ODM.