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Search Results: 1 - 10 of 409549 matches for " Jonathan M. Budzik "
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Pyrazinamide Resistance, Mycobacterium tuberculosis Lineage and Treatment Outcomes in San Francisco, California
Jonathan M. Budzik, Leah G. Jarlsberg, Julie Higashi, Jennifer Grinsdale, Phil C. Hopewell, Midori Kato-Maeda, Payam Nahid
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095645
Abstract: Background Pyrazinamide (PZA) is a first line agent for the treatment of active tuberculosis. PZA is also considered a potent companion drug for newer regimens under development. There are limited data on the demographic, clinical, and pathogen characteristics of PZA resistant tuberculosis. Methods Using a retrospective cohort study design, we evaluated all PZA resistant M. tuberculosis (M.tb) and M. bovis cases reported in San Francisco from 1991 to 2011. Demographic, clinical, and molecular data were analyzed. M.tb lineage was determined for all PZA resistant strains and compared to PZA susceptible strains. Results PZA resistance was identified in 1.8% (50 of 2,842) of mycobacterial isolates tested, corresponding to a case rate of 0.3 per 100,000 in the population. Monoresistant PZA infection was associated with the Hispanic population ([OR], 6.3; 95% [CI], 1.97–20.16) and 48% of cases were due to M. bovis. Infection with monoresistant PZA was also associated with extrapulmonary disease ([OR], 6.0; 95% [CI], 2.70–13.26). There was no statistically significant difference between treatment failure and mortality rates in patients infected with PZA monoresistance compared to pansusceptible controls (4% vs. 8%, p = 0.51), or those with PZA and MDR resistance (PZA-MDR) compared to MDR controls (18% vs. 29%, p = 0.40). PZA resistance was not associated with M.tb lineage. Conclusions Across two decades of comprehensive epidemiologic data on tuberculosis in San Francisco County, PZA resistance was uncommon. PZA resistance caused predominantly extrapulmonary disease and was more common in Hispanics compared to other ethnicities, with nearly half the cases attributed to M. bovis. No association was found between PZA monoresistance and M.tb lineage. Treatment outcomes were not adversely influenced by the presence of PZA resistance.
Hybrid foundry patterns of bevel gears
Budzik G.,Markowski T.,Sobolak M.
Archives of Foundry Engineering , 2007,
Abstract: Possibilities of making hybrid foundry patterns of bevel gears for investment casting process are presented. Rapid prototyping of gears with complex tooth forms is possible with the use of modern methods. One of such methods is the stereo-lithography, where a pattern is obtained as a result of resin curing with laser beam. Patterns of that type are applicable in precision casting. Removing of stereo-lithographic pattern from foundry mould requires use of high temperatures. Resin burning would generate significant amounts of harmful gases. In case of a solid stereo-lithographic pattern, the pressure created during gas burning may cause the mould to crack. A gas volume reduction may be achieved by using patterns of honeycomb structure. However, this technique causes a significant worsening of accuracy of stereo-lithographic patterns in respect of their dimensions and shape. In cooperation with WSK PZL Rzeszów, the Machine Design Department of Rzeszow University of Technology carried out research on the design of hybrid stereo-lithographic patterns. Hybrid pattern consists of a section made by stereo-lithographic process and a section made of casting wax. The latter material is used for stereo-lithographic pattern filling and for mould gating system. The hybrid pattern process consists of two stages: wax melting and then the burn-out of stereolithographic pattern. Use of hybrid patterns reduces the costs of production of stereolithographic patterns. High dimensional accuracy remains preserved in this process.
The scope of application of incremental rapid prototyping methods in foundry engineering
M. Stankiewicz,G. Budzik,M. Patrza?ek,M. Wieczorowski
Archives of Foundry Engineering , 2010,
Abstract: The article presents the scope of application of selected incremental Rapid Prototyping methods in the process of manufacturing casting models, casting moulds and casts. The Rapid Prototyping methods (SL, SLA, FDM, 3DP, JS) are predominantly used for the production of models and model sets for casting moulds. The Rapid Tooling methods, such as: ZCast-3DP, ProMetalRCT and VoxelJet, enable the fabrication of casting moulds in the incremental process. The application of the RP methods in cast production makes it possible to speed up the prototype preparation process. This is particularly vital to elements of complex shapes. The time required for the manufacture of the model, the mould and the cast proper may vary from a few to several dozen hours.
The application of optical measurements for the determination of accuracy of gear wheels casts manufactured in the RT/RP process
G. Budzik,M. Oleksy,M. Grzelka,M. Wieczorowski
Archives of Foundry Engineering , 2010,
Abstract: The article discusses the possibilities of using optical measurements for defining the geometric accuracy of gear wheels casts manufactured in the rapid prototyping process. The tested gear wheel prototype was cast using an aluminum alloy. The casting mould was made by means of the three-dimensional print method (3DP) with the use of a Z510 Spectrum device. The aim of the tests was to determine the geometric accuracy of the cast made by the ZCast technology in the rapid prototyping process. The tests were conducted with the use of the coordinate optical measuring method and a GOM measuring device. The prototype measurements were made in the scanning mode. The results of the measurements, saved in the STL format with the use of the scanning device software, were compared with the gear wheel 3D-CAD nominal model. The measurements enabled the determination of the real accuracy of prototypes manufactured in casting moulds by means of the ZCast technology. The selection of the measuring method was also analyzed in terms of measurement accuracy and the RP technology precision.
The use of optical scanning for analysis of casting shape
M. Wieczorowski,M. Grzelka,G. Budzik,J. Augustyn-Pieniazek
Archives of Foundry Engineering , 2011,
Abstract: In the paper the use of optical scanning for inspection of casting shape and its accuracy was described. Optical system applied todigitization of objects determines all dimensions and shape of inspected object. This technology is used in quality control and reverse engineering. System is based on triangulation: sensor head performs projection of different patterns of fringes onto measured object and scanner tracks their distribution with two cameras. Basing on optical transform equations, a processing unit automatically and with remarkable accuracy calculates 3D coordinates for every pixel of camera. Depending on camera resolution the result of such a scan is acloud of points with up to 5 million points for every image. In the paper examples of applications for castings with different designationwas presented.
The influence of changes of combustion gas temperature during flow around the horizontal cylinder on local Nu number
M. Górska,L. Szecówka,R. Budzik
Metalurgija , 2009,
Abstract: The article the influence of changes of combustion gas temperature during flow around of horizontal cylinder on local Nu number was presented. In order to test an influence of effect waste gas temperature cycle of experimental investigations were conducted. Experimental tests were carried out on a properly designed measuring cylinder furnished with a number of thermocouples embedded along the cylinder perimeter. The cylinder was made from stainless steel of known thermal conductivity, and was cooled on the outer side through a water cooling system. The cylinder was placed horizontally in a heating chamber equipped with an axially positioned gas burner fired with natural gas. Gas and air feeds were regulated with control valves, based on combustion gas analyzer data.
The analysis of the wax foundry models fabrication process for the CPX3000 device
G. Budzik,B. Kozik,J. Bernaczek,M. Wieczorowski
Archives of Foundry Engineering , 2011,
Abstract: The paper presents possibilities of creating wax founding models by means of CPX3000 device. The device is used for Rapid Prototypingof models made of foundry wax in an incremental process. The paper also presents problems connected with choosing technologicalparameters for incremental shaping which influence the accuracy of created models. Issues connected with post-processing are alsodescribed. This process is of great importance for obtaining geometrically correct models. The analysis of parameters of cleaning models from supporting material is also presented. At present CPX3000 printer is the first used in Poland device by 3D Systems firm for creating wax models. The printer is at The Faculty of Mechanical Engineering at Rzeszów University of Technology.
Accuracy of the photogrametric measuring system for large size elements
M. Grzelka,G. Budzik,L. Marciniak,B. Gapiński
Archives of Foundry Engineering , 2011,
Abstract: The aim of this paper is to present methods of estimating and guidelines for verifying the accuracy of optical photogrammetric measuringsystems, using for measurement of large size elements. Measuring systems applied to measure workpieces of a large size which oftenreach more than 10000mm require use of appropriate standards. Those standards provided by the manufacturer of photogrammetricsystems are certified and are inspected annually. To make sure that these systems work properly there was developed a special standardVDI / VDE 2634, "Optical 3D measuring systems. Imaging systems with point - by - point probing. " According to recommendationsdescribed in this standard research on accuracy of photogrametric measuring system was conducted using K class gauge blocks dedicatedto calibrate and test accuracy of classic CMMs. The paper presents results of research of estimation the actual error of indication for sizemeasurement MPEE for photogrammetric coordinate measuring system TRITOP.
Rapid Prototyping of wax foundry models in an incremental process
B. Kozik,G. Budzik,T. Dziubek,M. Grzelka
Archives of Foundry Engineering , 2011,
Abstract: The paper presents an analysis incremental methods of creating wax founding models. There are two methods of Rapid Prototypingof wax models in an incremental process which are more and more often used in industrial practice and in scientific research.Applying Rapid Prototyping methods in the process of making casts allows for acceleration of work on preparing prototypes. It isespecially important in case of element having complicated shapes. The time of making a wax model depending on the size and the appliedRP method may vary from several to a few dozen hours.
Optical coordinate scanners applied for the inspection of large scale housings produced in foundry technology
M. Grzelka,J. Chajda,G. Budzik,A. Gessner
Archives of Foundry Engineering , 2010,
Abstract: The paper presents possibilities of the dimensional and geometry measurement of the large scale casting details with a coordinate measuring technique. In particular, the analysis has been devoted to the measurement strategy in case of the measurement of large scale detail (larger than 1000 mm) made in foundry technology, with the 3D optical scanner. The attention was paid on the possibility created by the advanced software attached to the scanner for measurement data processing. Preparation to the geometrical accuracy analysis of the measured objects consisted of the identification of particular geometrical features based on the large number of probing points, as well as the creation of the coordinate systems derived from the best-fitting algorithms which calculate the inscribed or circumscribed geometrical elements. Analysis of accuracy in every probing point has been performed through the comparison of their coordinates with nominal values set by 3D model. Application of the 3D optical coordinate scanner with advanced measurement software for the manufacturing accuracy inspection is very useful in case of large scale details produced with foundry technologies and allows to carry out full accuracy analysis of the examined detail.
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