INTRODUCTIONKlebsiella pneumoniae is one of the main opportunistic pathogens which can cause different types of infections. Production of beta-lactamases like AmpC and ESBL mostly lead to beta-lactam ...resistance in these Gram-Negative bacteria. The aim of this study was the detection of AmpC-producing K. pneumoniae in clinical isolates.MATERIALS AND METHODSThree hundred and three isolates of K. pneumoniae were identified. Double disc method including cefoxitin with cefepime and using boronic acid with cloxacillin were performed as two phenotypic methods for detection of AmpC. Amplification of AmpC gene was performed by PCR.RESULTSEight and three isolates showed positive results in double disc method and by using boronic acid with cloxacillin, respectively. Five isolates had specific band for AmpC gene after electrophoresis.CONCLUSIONOur results were indicated the low prevalence of AmpC-producer-K. pnemoniae in Iran. On the other hand these two tested phenotypic methods showed low sensitivity for detection of AmpC.
Background: Carbapenem resistance due to the production of metallo-β -lactamase (MBL) in Gram-negative organism is an increasing public health problem. Aim: The purpose of this study is to detectMBL ...in Gram Negative bacterial isolates among Ventilator Associated Pneumonia patients. Materials and Methods: Phenotypic detection of MBL was done by three methods: 1.Modified Hodge Test (MHT) 2.Combined disc test (CDT) 3.Double Disc Synergy Test (DDST). Results: Out of 126 gram negative bacterial isolates, 80 (63.49%) showed resistance to carbapenem group of drugs. Among them maximum resistance was shown by Acinetobacter baumanii (90.32%), followed by Klebseilla pneumoniae (45.7%), Pseudomonas aeruginosa (26%). Out of 80 isolates, 66 were positive for MBL by MHT, 64 by CDT and 61 were detected positive for MBL by DDST. Conclusion: MHT and CDT were found equally efficient method to detect MBL. Maximum MBL production was detected in Acinetobacter baumanii. Simple and accurate screening test is required to prevent the spread of nosocomial strain in hospitals.
Objective: To study the influence of disc cutter spacing on rock fragmentation efficiency and optimize cutter layout and improve the efficiency of disc cutter. Method: ANSYS, a finite element ...software was used to simulate double disc cutter cutting process. Result: Find a good corresponding relationship between penetration and cutter spacing. At the process of sandstone, if disc cutter spacing as 54 ~ 55 mm, rock crushing as the largest and rock fragmentation efficiency is the highest; with the penetration of 10 mm. If disc cutter spacing as 66~68.5mm, rock crushing as the largest and rock fragmentation efficiency is the highest with the penetration of 15 mm. Changing the cutter spacing and penetration, rock stress and broken degree will also change. Conclusion: Double disc cutters change within the range of best cutter spacing, cutter spacing is proportional to the rock crushing. If the cutter distance is greater than the best cutter spacing, the ledge will be appeared. For one type of rocks, the penetration would have some effects on the optimal cutter spacing. If the penetration increases, the optimal cutter spacing increases gradually, at the time of other construction parameters unchanged.
In 2008 Holmen Paper Braviken invested in a new TMP-line. The primary stage refining system of pressurized counter-rotating double disc chip refiners in this TMP line has been investigated. The aim ...of this work was to improve the energy efficiency through optimization of the refining temperature.The specific refining energy was varied at different refining temperatures. Inlet and housing pressures were used to control temperature. There was no pressure difference between inlet and housing pressure.An increased inlet- and housing pressure (from 4.6 up to 7.1 bar(g)) and thereby refining temperature resulted in a reduction of the energy consumption to same tensile index by 80-150 kWh/adt. The largest energy reduction was attained at low refining energy levels. An increase in energy efficiency may be explained by a decrease in plate gap, probably caused by softer fibre pad and lower steam volume. At constant specific refining energy and elevated temperature, the tensile index and light scattering coefficients were higher, shives content and average fibre length were lower. These results are probably due to the increased intensity resulting from the plate gap reduction.Increased refining pressure proved to have a positive effect on energy efficiency and pulp quality in a long term trial, i.e. throughout a plate-life.
Soil injection of animal slurry is increasingly being used to mitigate odour and ammonia (NH
3) emissions, but in order to perform injection in fields with growing cereal crops, injectors that have a ...greater working width than the existing equipment are needed. To reduce crop damage, a disc injector can be used, but due to the need for a high vertical load a simple tine is used in conjunction with the discs, to penetrate the soil more easily. This study investigates how to reduce horizontal and vertical forces when operating the combination of a double disc and tine injector.
An experimental force-measuring system was built with the purpose of making simultaneous force measurements in both field and soil bin studies. Two experiments were carried out in a soil bin facility in order to find the optimal placement of the tine in relation to the discs and the best working depths for the tine and discs. A field study was also done to evaluate the amount of crop damage caused by operating a prototype injector in a growing winter wheat crop.
The measuring system was found to provide very reliable data. To reduce horizontal and vertical forces, as well as crop damage, it was found that running the double discs at approximately 40
mm and the tine at 100
mm below the soil surface gave the best results. The tine should be placed as close as practically possible to the discs, with a rake angle of 40°. At this adjustment the horizontal force demand was reduced to 30–40% of what has been reported for comparable injectors.
A method to calculate the grinding disc-to-disc distance distribution in a double-disc grinder was described. Coordinate transformation using rotation matrices was applied to calculate the ...coordinates of arbitrary points on tilted and trued disc surfaces. Effects of disc tilt angles and truing on the disc-to-disc distance distribution were investigated by calculation using this method. The results indicated that to implement the "rough finishing - finishing - spark out" process in double-disc grinding, which requires a gently spreading gap following a rapid narrowing gap between the grinding disc surfaces along the workpiece path, both fixing of proper tilting angles and truing of the grinding discs are required.
Erosion due to turbulence is a predominant factor in plant design for slurry handling. DUCOM Instruments (P) Ltd. has built a “counter rotating double disc erosion tester” to analyse surfaces for ...erosion due to turbulence. Volume loss of Stainless Steel and aluminum as a function of varying time, particle hardness, speed and slurry concentration is evaluated in this erosion tester. Individual study on the effect of corrosion on the total volume loss is conducted and found to be high in alumina slurry and low in silica slurry.
A cultura do arroz adapta-se pouco ao sistema plantio direto (SPD) em razão da maior compactação da camada superficial do solo, devido ao intenso tráfego de máquinas e não mobilização do solo. Nesse ...caso, o mecanismo utilizado na semeadora para a abertura dos sulcos com a finalidade de deposição do adubo pode ter grande importância para facilitar a penetração das raízes e aumentar a porosidade do solo. Diante disso, propôs-se este estudo com o objetivo de avaliar o desenvolvimento e a produtividade do arroz de terras altas em sistema plantio direto, em razão de mecanismos de distribuição do adubo na semeadura e de doses de N em cobertura, em Selvíria, Mato Grosso do Sul. O delineamento experimental utilizado foi em blocos casualizados, utilizando-se um esquema fatorial 2 x 6, constituído por mecanismos de distribuição do adubo (haste escarificadora e disco duplo) e de doses de N em cobertura (0, 25, 50, 75, 100 e 125 kg ha-1), com quatro repetições. Concluiu-se que os mecanismos de distribuição do fertilizante não interferiram na produtividade de grãos do arroz de terras altas; o mecanismo do tipo haste escarificadora promoveu maior altura de plantas e maior número de grãos cheios nos dois anos de cultivo; a aplicação de nitrogênio em cobertura interferiu em algumas características agronômicas, produtivas e em componentes de rendimento de engenho; a produtividade do arroz aumentou até a dose de 69 kg ha-1 de N, no primeiro ano de cultivo.
The goal with this work was to study the effect of segment design on electrical energy consumption and pulp quality in double disc TMP production. Mill scale trials were performed with refiner ...segments from Metso, which were designed based on the fluid dynamics theory. The calculated intensity for the different segments was related to the measured pulp quality. Refining with the high intensity segments (Turbine (TM)) produced pulp with similar tensile index and a significantly higher specific light scattering coefficient at certain specific energy consumption when compared with the reference segments. One drawback with the high intensity segments was the limited operating window due to fibre cutting. The trials showed that segment performance can be modelled, which facilitates the development of new segment designs.
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