bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasound Promoted Synthesis and Antibacterial Activity of 5-Aryl-l,3,4-oxadiazole-2-yl Sulfanyl Derivatives
Authors: Lei Ying Jie , Wu Xin Shi , Ding Mei
Published: October 2013

In order to search for new bioactive substances containing 1,3,4-oxadiazole, some 5-aryl-l,3,4-oxadiazole-2-ylsulfanyl derivatives were synthesized from the active intermediate 5-aryl-l,3,4-oxadiazole-2-thiones, obtained from the condensation of aromatic carboxylic acid hydrazides and carbon disulfide at triethylamine alkaline solution catalyzed by propylphosphonic anhydride, followed by reaction with ethyl chloroacetate in alkaline media under ultrasound irradiation in the presence of PEG-400. The structural features were confirmed by IR, 1HNMR spectra and elemental analysis. These compounds have been screened for their good antibacterial activities against Escherichia coli, Staphyhcoccus aureus and Bacillus Subtilis.
Preparation of Barium Titanate/Polyimide Composite Film and its Dielectric Properties
Authors: Wang Ya Jun , Wu Xiao Juan
Published: October 2013

Polyimide (PI) was chosen as the matrix of the composites, barium titanate/polyimide (BT/PI) nanocomposite films were prepared with in-situ polymerization. The morphology of the samples was obtained by SEM. The factors affecting the dielectric properties are discussed. When the mass fraction of BT is 70%, the dielectric constant will be 19.32, and loss 0.00254 (at 103 Hz). The optimal solvent content and ultrasonic time were 9.2 ml and 30 min respectively. TG analysis shows that the film is stable below 500°C. The AC breakdown strength were 42 MV·m-1 and 64 MV·m-1 for 70% BT/PI and 60% BT/PI respectively, and corresponding energy storage density were 0.17 J·cm-3 and 0.30 J·cm-3 respectively.
Genome Analysis of the Psychrotolerant Acidophile Acidithiobacillus ferrivorans CF27
Authors: Talla Emmanuel , Hedrich Sabrina , Ji Bo Yang , Johnson D. Barrie , Bonnefoy Violaine
Published: October 2013

Four well-differentiated clusters have been identified among iron-oxidizing acidithiobacilli.One monophyletic group clusters withAt. ferrooxidansTand another with strains ofAt. ferrivorans. WhileAt.ferrooxidansandAt. ferrivoransshare many physiological traits, they differ in some phenotypic characteristics such as motility, pH and temperature minima, and also in terms of genes involved in ferrous iron oxidation. The genome of a strain (CF27) ofAt. ferrivorans, which is characterized by its marked propensity to form macroscopic growths and biofilms, was sequenced at Genoscope (Evry, France). Comparative genomic studies were carried with all relatedAcidithiobacillusstrains that have been sequenced to date, in order to identify genetic determinants responsible for physiological traits relating to the oxidation of iron and sulfur, and also to extracellular polymeric substances formation.
Variance Calculations for Quantitative Real-Time PCR Experiments with Multiple Levels of Replication
Authors: Soto-Rojo Susana , Glonek Gary , Demergasso Cecilia , Galleguillos Pedro A. , Solomon Patty , Tapia P. , Acosta Mauricio
Published: October 2013

Heap bioleaching is an established technology for recovering copper from low-grade sulphide ores. Recently, genetics-based approaches have been employed to characterize mineral-processing bacteria. In these approaches, data analysis is a key issue. Consequently, it is of fundamental importance to provide adequate mathematical models and statistical tools to draw reliable conclusions. The present work relates to current studies of the consortium of organisms inhabiting the bioleaching heap of the Escondida mine in Northern Chile. These studies aim to describe and understand the relationship between the dynamics of the community and the performance of the industrial process. Here, we consider a series of quantitative real-time polymerase chain reaction (PCR) experiments performed to quantify six different microorganisms at various stages of the bioleaching cycle. Establishing the reliability of the data obtained by real-time PCR requires the estimation of the error variance at several different levels. The results obtained show that the sampling component of the error variance is the dominant source of variability for most microorganisms. An estimate for the proportional reduction in residual standard deviation from the use of extraction and real-time PCR triplicates was found to range from 3% to 27% for the different organisms. This result suggests that triplicate assays would produce only a modest reduction in error variance compared to more frequent sampling from the heap.
Analysis of the Bacterial Sulphur System
Authors: Candy Rachel M. , Blight Kyle R. , Ralph David E.
Published: October 2013

Heterogeneous bacterial sulphur systems are inherently complicated. However, developing an understanding of the influence of environmental factors such as pH,Iand PCO2is important for a number of fields. Examples of these include minimising acid mine drainage and maximising metal recovery from low-grade sulphide minerals. Measuring the effect of these factors on the extent and rate of sulphur (S) oxidation is complicated by the presence and nature of solid phase elemental S. The rate and extent of S oxidation can be determined indirectly via the reaction product, H2SO4, which was quantified using pH measurements in this study. The method was critically dependent on the quality of pH data but proved effective in providing rate constants for the catalysed S oxidation reaction and yield (biomass/substrate) estimates in the range pH > 1.5. IncreasingIover the range 0.176 0.367 mol L-1decreased bacterial cell yields but increased the rate of sulphur oxidation significantly. Partial pressures of CO2in the range of 0.039 1.18% v/v produced no significant effect on the rates of S oxidation or bacterial cell yields. Bacterial cell yields were not affected in the pH range 1.5 2.5, however the rate of S oxidation increased significantly from pH 2.0 2.5. In the range pH < 1.5 the batch cultures progressed and although no reliable rate data was recorded cell yields decreased from 7.43 to 2.05 (× 1012cells mol-1) at pH 1.5 to 1.0 respectively.
Evidence for Widespread Dissimilatory Hydrogen Metabolism among Acidophilic Bacteria
Authors: Hedrich Sabrina , Johnson D. Barrie
Published: October 2013

Acidithiobacillus ferrooxidansis the only acidophilic bacterium to have been reported to grow using hydrogen as sole electron donor. Hydrogen is a potentially widely available energy source in acidic environments and therefore may have more ubiquitous use among indigenous prokaryotes than currently recognized. To test this hypothesis, thirty-seven strains of acidophilic bacteria, including 24 separate designated and proposed species, were screened for their abilities to use the dissimilatory oxidation of hydrogen to support their growth. Positive results were obtained with all strains of Group I (Acidithiobacillus ferrooxidans) and Group II (At. ferridurans) iron-oxidizing acidithiobacilli,At. caldus, the three species ofSulfobacillustested, andAcidimicrobium ferrooxidans. Growth yields approaching 1010cells ml-1were obtained for aerobic growth ofAt. ferrooxidansandAt. ferriduranson hydrogen.
A Novel Apparatus to Determine the Bio-Oxidation Kinetics of Sessile Leptospirillum ferriphilum
Authors: Duku Porogo , Minnaar Sanet H. , Harrison Susan T.L. , Petersen Jochen
Published: October 2013

A novel apparatus was developed to test the ferrous iron oxidation kinetics of Leptospirillum ferriphilum in predominantly sessile culture, by combining a CSTR under wash-out conditions with a packed bed of inert ceramic saddles. Results indicate that a dense culture of sessile bacteria is established rapidly, which achieves high oxidation rates in all experiments with a yield in terms of CO2 uptake rates comparable or higher to what has been measured in planktonic culture. However, the yield in terms of cell counts changes dramatically, indicating a substantial shift in carbon utilisation in the sessile culture. The apparatus is feasible as a method to study iron oxidation kinetics of sessile cultures, providing it is operated at sufficiently high recycle ratios.
Bio-Hydrometallurgical Processing of Non-Ferrous Metals from Copper Smelting Slag
Authors: Ilyas Sadia , Lee Jae Chun , Shin Do Yun , Kim Byung Su
Published: October 2013

Stirred tank reactor (STR) leaching of non-ferrous metals from copper smelting slag was conducted using biogenic Fe3+solution containing H2SO4. The solution was initially obtained through biooxidation of FeS2+S° byusing a moderately thermophilic microbial culture such asSulfobacillus thermosulfidooxidansat 45°C and was applied as lixiviant in STR leaching experiments. The effect of pH, pulp density, temperature and initial Fe3+concentration on leaching behavior of Cu, Fe, Zn and Ni from the slag were investigated. The presence of high concentration of Fe3+ions was found to promote the leaching of copper and nickel while inhibiting the leaching of zinc and iron. Process pH was considered as the most significant parameter and the optimum leaching results were obtained at pH 1.8 with low fayalite dissolution and jarosite precipitation. During the leaching at this pH (1.8), 25% (w/v) pulp density and 65°C temperature in presence of 20 g/L initial Fe3+concentration, maximum extraction of Cu (90%) and Ni (85%) was observed in 4 hours whereas Fe extraction was minimum (19%). A schematic flowsheet of multistage leaching process was proposed. The result obtained from multistage batch leaching experiments will be step forward for continuous stirred tank reactor leaching for industrial scale implementation.
Geochemistry and Microbiology in an Acidic, High Altitude (4,000 m) Salt Flat — High Andes, Northern Chile
Authors: Escudero Lorena V. , Bijman Jonathan , Chong Guillermo , Pueyo Juan Jose , Demergasso Cecilia
Published: October 2013

Acidic saline lake systems are an uncommon type of natural extreme environment described in Northern Chile and in Australia. These environments are considered a terrestrial analogue to certain ancient Martian terrains and a source of new material for biotechnological applications as bioleaching at high ionic strength conditions and biological systems for precipitating metal sulfides. The aim of this study is to describe the occurrence of redox couples that support prokaryotic life in the system and to obtain representative cultures of predominant microorganisms/metabolisms. Mapping of the area of interest and geochemical analysis of sediments, bedrock and water samples were performed. The original microbial community and enriched cultures were studied by direct count and culturing dependent and independent techniques. In the distal part of the alluvial fans some ponds are found with acidic brines (up to pH 1) of the Cl-SO4-Na (-Mg) type that are surrounded by yellow efflorescences. Other ponds towards the basin center progressively increase in concentration due to capillary evaporation. Brines are rich in aluminium and boron with lower concentration of manganese, lithium, iron and arsenic. An advanced hydrothermal argillic alteration affecting the country rocks, native sulfur associated to active solfataras, alunite and jarosite occurrences in sediments and chloride and sulfate efflorescent salts were evidenced. The microbial community in brines and sediments (105 and 106 cells/mL, respectively) was dominated by Firmicutes, Proteobacteria and Actinobacteria, and by Proteobacteria and Cyanobacteria, respectively. Sulphur and iron oxidation activity were detected depending on the salinity of the samples. Culture enrichments that respire and reduce As (V) and sulfate have been only obtained from sites with the highest pH (4-5). Microbial assemblages in those heterotrophic cultures were closely related to the Gamma and Betaproteobacteria, meanwhile, Rhodanobacter and Shewanella were the only microorganisms detected in the autotrophic cultures supplemented by Na2S and by H2. Relevant information to describe the occurring surface biogeochemical processes in that acidic saline system has been obtained. In addition, the occurrence of new prokaryotic genera capable of arsenic redox transformation has been evidenced in acidic systems.
Column Bioleaching Experiment of Low Grade Uranium Ore from Xiangshan Uranium Deposit
Authors: Liu Jin Hui , Liu Ya Jie , Zheng Zhi Hong , Wang Xue Gang , Zhou Yi Peng , Sun Zhan Xue , Shi Wei Jun
Published: October 2013

Xiangshan uranium deposit is the largest volcanic rock type uranium ore in China. Great number of low grade uranium ore (U < 0.03%) was stacked in the tailings dam as a waste rock in more than 50 years of exploitation, resulted in uranium resources waste. Two group column bioleaching experiments (column AB) were carried on in order to investigate uranium recovery effect by microbial for the low grade uranium ore. The bacteria for the tests was a mixture mainly composed by Acidithobacullus ferrooxidans and Leptospirrillum ferriphilum, which was isolated from the uranium minerals of Xiangshan uranium deposit and domesticated with the mineral and leachate system. The average uranium content is 0.0123%, the particle sizes for column A and B is less than 25mm The Fe2+, Fe3+ and F- average contents of the test minerals were 1.90%, 0.59% and 0.14% respectively. Results showed that uranium leaching rate calculated by uranium concentration of slag were 76.75%, 75.31% in 95days and 85 days of test column A, B respectively. Rate of acid consumption of column test A, B were 7.60% and 7.69% respectively. while the rate of acid consumption was usually more than 10% by acid leaching. These evidences suggested that microbial hydrometallurgical technology was had effective for the low grade uranium ore and significant on uranium recovery for the low grade uranium ores.
Quantification of the Microbial Community in Lateritic Deposits
Authors: Coto Pérez Orquidea , Marrero Coto Jeannette , Schippers Axel
Published: October 2013

Lateritic deposits contain oxide ores and usually consist of three layers, namely the limonitic, the saprolite and the garnieritic layer. Limonite, which comprises the top lateritic layer, is a homogeneous ore consisting mainly of goethite with which nickel is associated. Microbe-mineral interactions are of interest for biogeochemical cycles. Microorganisms which are able to mediate redox transformation of Fe-oxide containing minerals are of particular interest when effective bioremediation strategies for insoluble hydroxide and oxide minerals are designed. Quantitive real-time polymerase chain reaction (qPCR) is a culture independent method which is used for the quantification of environmental microorganisms. The aim of this work was to enumerate the microorganisms in different lateritic deposits at Moa mine (Holguin, Cuba) by qPCR and also to obtain Fe (III)-reducing enrichment cultures. A higher microbial abundance was detected in the sampling sites 5124 and 5125 and a lower one in the site 5121. Both, Archaea and Bacteria occurred in all samples except for site 5121 where Bacteria were not detected by qPCR. The Geobacteraceae which comprise Fe-(III)-reducing bacteria were detected at all five lateritic ore sites. The results indicate that these bacteria play a role fundamental in the formation of sediments with a number of oxidized or partially oxidized iron compounds such as magnetite, hematite, goethite and various Fe (III)-oxyhydroxides.
The Efficient Recovery of Cobalt from Low Grade Refractory Carrollite with Bioleaching Technology
Authors: Chen Guo Bao , Yang Hong Ying , Zhou Li Jie
Published: October 2013

Cobalt, having many diverse and critical uses, is an essential metal in today's society. However, the recovery of cobalt is difficult due to its associated mineral characteristics. A biohydrometallurgical process has been developed for cobalt recovery from low grade refractory carrollite. After direct oxidation for 6 days, 96.51 % Co and 26.32 % Cu were extracted from the ore using a pulp density of 10 %. The bioleaching solution contained 22.62 gL-1 ferric iron while the concentration of cobalt was only 0.83 gL-1. Therefore, a goethite deironization process was then conducted. Different conditions, such as pH value, temperature, standing time and oxidant concentration were studied in detail. The results showed that when the pH value was 4.0, oxidation temperature was 70 °C, standing time was 1 h, and oxidant concentration was 8%, then the iron removal and the loss of cobalt were 99.9 % and 0.5 %, respectively. The goethite precipitate had good filterability. The sum recovery of cobalt in the whole extraction process attained more than 95 %. The biohydrometallurgy process for the recovery of cobalt has economic and environmental advantages over the other methods.
Treatment of a Nickel-Copper Sulphide Concentrate Using Bioleaching
Authors: Gericke Mariekie , Robertson Stefan
Published: October 2013

This paper describes bioleach test work performed in continuously operated bench-scale reactor systems on a nickel-copper containing sulphide concentrate at 45 and 70°C, respectively. Optimisation of the process focused on determining the effects of process parameters such as residence time, grind size and feed solids concentration on the leach kinetics, metal extractions and performance of both the moderate thermophile and thermophile cultures. The results showed that nickel recoveries in excess of 96% could be achieved using a moderate grind size and leach temperatures, whereas ultrafine grinding and higher operating temperatures were required to achieve Cu extractions in excess of 93%.
Influence of Sulfate-Reducing Bacteria on the Mobility of Arsenic in Soils an "In Vitro" Study
Authors: Lopes Lillian Rabelo , Teixeira Mônica Cristina
Published: October 2013

Ouro Preto/MG/Brazil soils are rich in arsenic containing minerals that once solubilized may contaminate water or food. Arsenic (As) is toxic if ingested or inhaled. Microorganisms and organic matter plays an important role in the dynamics of As in soils and sediments affecting its mobilization. Aims: to study the mobility of arsenic in the presence of organic matter and sulfur reducing bacteria (SRB) and also to obtain some As resistant bacterial cultures. Materials: Soil samples were collected from abandoned gold mines named Old Mine, Chico Rei and Santa Rita. As content in solid samples were in a range of 465 to 1829 mg Kg-1. Soil samples (5 g) were mixed with 35 ml of 2.5 M, CaCl2, stirred (5 min) and allowed to rest at 21.0°C for 1, 30, 60, 90 and 120 days. Other set of experiments were prepared following the previous procedure with some modifications: (i) group 1, flasks with bacterial inoculum (4 ml) from an enrichment of 5 g of soil and 45 ml of liquid medium B Postgate, pH 7.0, incubated at 35°C under anaerobic conditions; (ii) group 2, flasks with (5 g) of organic matter with As (III) adsorptive capacity (powdered chicken feathers - PCF), and (iii) group 3, flasks containing bacterial inoculum and organic matter. Results: As solubility was inversely proportional to time and depends on Fe and Mn contents. The influence of microorganisms on As immobilization was more relevant than the presence of organic matter. Surprisingly, in some cases, As solubility enhanced in the presence of PCF besides its As adsorptive capacity. One microbial consortium adapted to the culturing at pH 5.0 was obtained and this is an interesting feature considering the acid pH of the studied arsenic soils. Indigenous bacteria phenotypically similar to SRB may contribute to As immobilization in natural or impacted environment.
Removal of Anionic Metalloid/Metals by PEI-Modified Corynebacterium glutamicum
Authors: Kim Namgyu , Park Munsik , Park Jongmoon , Park Donghee
Published: October 2013

An anionic biosorbent was derived from an industrial fermentation biowate, Corynebacterium glutamicum, by being cross-linked with polyethylenimine (PEI). A fiber form of the biosorbent was used to examine its potentiality of removing anionic metals such as As (V), Cr (VI) and Mn (VII) in aqueous system. As (V) and Cr (VI) were efficiently removed by the biosorbent through anionic adsorption mechanism. Sulfate ion seriously inhibited adsorption of the anionic metals through competitive inhibition with respect to the binding site of the biosorbent. In the case of Mn (VII), its removal mechanism by the biosorbent was not anionic adsorption. Mn (VII) was completely removed in aqueous phase, meanwhile, Mn (II) appeared and increased in proportion to the Mn (VII) depletion. As a result, adsorption coupled reduction was chosen as the mechanism of Mn (VII) removal by the biosorbent. In conclusion, the anionic biosorbent could be used to remove various anionic metals from aqueous solution through anionic adsorption or reduction mechanism.
Microbial Diversity in Acidic Anaerobic Sediments at the Geothermal Caviahue-Copahue System, Argentina
Authors: Willis Graciana , Hedrich Sabrina , Nancucheo Ivan , Johnson D. Barrie , Donati Edgardo R.
Published: October 2013

In this work we have examined the bacterial diversity from the hot spring sediment Agua del Limón (AL1) present at the geothermal Caviahue-Copahue system using a combination of molecular and cultivation techniques, with particular emphasis on indigenous anaerobic prokaryotes. Microorganisms involved in the iron (Acidithiobacillus ferrooxidansandLeptospirillumspp.) and sulphur (Acidithiobacillusspp., Thermotogales-like bacteria,Thiomonassp., andDesulfurellasp.) cycles were identified in the clone library. Although no obvious sulfate-reducing bacteria were detected by culture-independent techniques, several isolates related to the mesophilic, spore-forming sulfate-reducer"Desulfobacillus acidavidus"strain CL4 were isolated at 30°C and 40°C. The 16S rRNA gene of another isolate showed 94% similarity toDesulfotomaculum thermobenzoicum. Sulfate-reducing enrichment cultures of the Copahue samples were also dominated by"Dsb. acidavidus"CL4.
Health Effects from Occupational Exposure to Metalworking Fluid Mist
Authors: Semanová Petra , Kučera Marián
Published: October 2013

Metalworking fluids (MWFs) are an essential part of a technological process. They are used in machining operations for enhancing cutting process performance. The performance of MWFs depends on properties such as specific heat, viscosity, density and thermal conductivity. MWFs are used to cool and lubricate the cutting zone, flush away chips and inhibit corrosion during machining operations. On the other hand, MWFs are associated with formation of liquid aerosols (mists) that represents two types of occupational risk factors for machine operators - chemical and biological. Epidemiological assessments with machine operators in the metalworking industry have identified dermatologic and respiratory effects. The aim of this article is to review what is known about health effects from inhalation exposure to mist from various types of MWFs.
Determination of the Chip Width and the Undeformed Chip Thickness in Rotational Turning
Authors: Sztankovics István , Kundrák János
Published: October 2013

The accurate knowledge of the defining parameters of chip removal in rotational turning is necessary for the description of the complex kinematic relations. In this paper two characteristic parameters of the chip cross-sectional area undeformed equivalent chip thickness, chip width is defined. Lastly the application of the gained relation is shown for a specific example.
Advanced Materials in Sheet Metal Forming
Authors: Tisza Miklós
Published: October 2013

In this paper, some recent developments in materials applied in sheet metal forming processes will be overviewed mainly from the viewpoint of automotive industry as one of the most important application fields. If we consider the main requirements in the automotive industry we can state that there are very contradictory demands on developments. Better performance with lower consumption and lower harmful emission, more safety and comfort are hardly available simultaneously with conventional materials and conventional manufacturing processes. These requirements are the main driving forces behind the material and technological developments in sheet metal forming: application of high strength steels, low weight light alloys and the appropriate non-conventional forming processes are the main target fields of developments summarized in this paper.
Cutting Data Influence on Cutting Forces and Surface Finish during Sintered Carbide Turning
Authors: Zębala Wojciech , Kowalczyk Robert
Published: October 2013

The paper presents research of turning of super hard materials, like sintered carbides, with PCD (polycrystalline diamond) tools. Sintered carbides with cobalt, as metal binder, with good properties of abrasion resistant in high temperature environment are used as construction material. These materials, produced by a powder metallurgy process, are difficult-to-machine because of their high hardness and brittleness. In the work, a special attention was paid on the cutting force component Fc and surface finish, in the form of roughness parameter Ra, at variable cutting data (cutting speed vc, feed f and depth of cut ap). The test stand for research was consisted of the precise lathe, work piece (a tungsten carbides rod with 25% Co content), tool holder of DTGNR 2020K16 type, insert of TNGA type with PCD edges, Kistler force dynamometer and Taylor Hobson profilometer. Taguchi design and ANOVA analysis were applied.
Effect of Workpiece Hardness on Surface Microgeometry when Hard Turning with Ceramic Inserts
Authors: Maňková Ildikó , Beňo Jozef , Vrabel' Marek
Published: October 2013

Hard turning provides an alternative to grinding in some finishing operations. This paper deals with analysis of part surface finishing when turning hardened steel heat-treated on hardness of 46, 55 and 60 HRC with mixed oxide ceramic inserts. Average surface roughness Ra has been widely used in industry it is known that the single parameter Ra is inadequate to define the functionality of a surface. Two different surfaces with similar values of Ra can behave differently under loading conditions. The surface profile 2D and 3D parameters are assessed. The influence of workpiece hardness on surface roughness parameters and cutting force components is investigated. Results show that finish hard turning with mixed ceramic tool produces surface profile comparable to those produced by grinding.
Detail Study and Analysis of Durability for Selected Cutting Materials According to Taylor's Theory
Authors: Duplák Ján , Čuma Matúš , Kormoš Miroslav
Published: October 2013

The main part of Standard ISO 3685 is T-vc dependence for various cutting materials. The Standard ISO 3685 contains main properties and characteristics for three most important cutting materials those are used in engineering practice. These cutting materials are used for cutting tools made of high speed steel, cutting ceramic and sintered carbide. Some types of cutting materials are defined by means of descriptions in standards ISO, some types by means of catalogues from the manufacturer. There are a lot of types of cutting materials they have not been defined theirs properties exactly yet and theirs properties have to be defined on experiments. There is a presumption that descriptions in standards ISO are not correct and these standards have to be examined and verified, because that this fact have to be confirmed or disproved. Accuracy and completeness technical standards ISO are very important part quality of manufacturing. Article describes process how to define T-vc dependence for cutting tools made of high speed steel, cutting ceramic and sintered carbide, because were found deficiencies in valid standard ISO 3685.
Surface Integrity of Metal Spun Parts
Authors: Šugár Peter , Šugárová Jana , Petrovič Ján
Published: October 2013

Sheet metal spinning is one of the forming processes based on gradual shaping of metal blank into an axisymetric part by a roller according to a model (mandrel). Very significant feature of spinning is ability to produce components with high mechanical properties and high quality of surface layers. The paper brings the results of surface integrity analysis of mild steel parts produced by CNC multi-pass conventional metal spinning. The influence of the spindle speed, feed rate, workpiece geometry and planar anisotropy of the blank on the residual stresses distribution and microhardness of formed part surfaces is studied. For experiment design, an orthogonal array L27(313) was used and ANOVA (Analysis of Variance) was carried out. Based on the results it is determined that the geometry of the formed part (radius, conical area, cylindrical area) is the significant factor influencing both residual stresses and microhardness of the formed part surfaces.
PMMA Surface Structure within CO2 Laser Micro-Machining
Authors: Sýkorová Libuše , Šuba Oldřich , Lukovics Imrich
Published: October 2013

This article presents some possibilities of laser micro-machining. Results of the laser micro-machining surface quality of product and his utility in specific application depend on the laser parameters and the polymer material type. From the obtained scientific knowledge it follows, that the character of surface machined by laser depends on thermal conductivity of polymer. The action of laser beam is best shown on specimens from PMMA, therefore tests were carried out with this material. Optimal parameters of CO2 laser for used material are presented in given study. Visual evaluation of action laser ray on surface of PMMA was made also.
Effects of Technological Parameters on the Surface Texture of Burnished Surfaces
Authors: Varga Gyula
Published: October 2013

In this study we analysed the process of diamond burnishing. We examined the effect of burnishing technological parameters on the surface roughness of the burnished surface, and on the improvement ratio of surface roughness. Parameters taking into consideration during examinations are burnishing speed, burnishing feed, and burnishing force. We determined a formula suitable for determination of the improvement ratio of surface roughness by the Factorial Experimental Design which is valid in the examined parameter range.
Verification of Manufacturing Accuracy of Mathematically Defined Shaped Surfaces on 3D CNC Milling Machine
Authors: Kráľ Ján , Kráľ Ján
Published: October 2013

Verification of programming of various control systems and production of mathematically defined shaped surfaces on 3D CNC milling machine is a challenging technological process. Appropriate design and optimization of tool path is essential for the production of high-quality surfaces with the required accuracy and roughness. This paper presents the design of shaped surfaces in various programming means in order to evaluate both the accuracy of the shape manufactured by the production machine and also by program created shapes for control systems of 3D milling machines. Based on the analysis of mathematically defined shaped surfaces to evaluate both accuracy of shape of 3D milling machine and also applied programs for the programming of the selected control system the shaped surface "Interface" was chosen. The advantage of mathematically described surface is a better way to evaluate the accuracy compare to surface modeled e.g. by Bezier ́s curves. Mathematically described surfaces enable us to optimize their shapes by available mathematical functions. Typical example the derivatives are, which make it possible to search extremes. Verification of the shaped surfaces accuracy according to created control programs was solved using the 3D Carl-Zeiss coordinate system and also HOLOS software. Verified programs for the NC machine programming were in CATIA V5, Pro/Engineer and EqCAM. The result is an optimally designed original EqCAM program for 3D CNC milling machine programming, which generates optimal NC codes and bypasses various built-in interpolations, and by precise control at every step it is possible to achieve maximum accuracy and quality of machined surface for each 3D CNC milling machine.
Finite Element Investigation of Acetabular Cups Used During Revisionist Surgery
Authors: Monostori Renáta
Published: October 2013

Serious coxarthosis which significantly impaires the quality of life; can be diagnosed in young ages of the patient too. Therefore, nowadays the prosthesis implantation is performed in the activest life period of the patient. Besides it is known that the replacement of the prosthesis will be necessary later. When acetabular cups were measured, the results were analyzed and the differences were determined, I made a simulation to observe the differences referring to the wear. Thereafter I compared the measured and calculated results introduced in the paper.
Contact Measurement of Flatness of Parts with Low Rigidity
Authors: Samardžiová Michaela , Kováč Martin , Necpal Martin
Published: October 2013

An article deals with a measurement of flatness of thin-walled parts with low rigidity. The flatness is important for quality thin-walled parts made by milling. Measurement of the variation in the flatness of thin-walled components conventional 3-axis, high-speed 3-axis milling was done. In the first part is description of flatness and definition of thin-walled parts. Second part characterizes the measuring system, the principle of measurement and experimental setup. The last part of this work is evaluation of the experiment, which compares different factors to determinate flatness during machining of thin-walled parts.
Determination of the Mechanical Properties of Thermally Treated Recycled Glass Based on Nano-Indentation Measurement and FEM Supported Simulation
Authors: Jamal Mikdam , Morgan Michael
Published: October 2013

This paper reports on an inverse finite element modelling (FEM) simulation developed from nanoindentation measurement data. The FEM simulation was used to predict the mechanical properties of a thermally treated recycled glass. This material is a patented innovation used to manufacture abrasive media for vibratory mass finishing processes. A parametric study of the accuracy of the simulation results has been completed to verify the FEM and to assess the influence of a variation in sample size, tip geometry, frictional condition and material properties on the force displacement curves during the loading and unloading stages. Also examined were the mesh density sensitivity and the effect of object boundary condition. The model was post-processed employing novel objective optimization algorithms in order to determine comprehensive material properties. It was found from the proposed optimization algorithms that the mechanical properties of an assumed elastic perfectly plastic material can be determined using only a single indenter geometry. The nanoindentation results show that the heat treatment cycle has a substantial effect on the predicted mechanical properties of the recycled glass.
Neural Network Assisted Particle Swarm Optimization of Machining Process
Authors: Zuperl Uros , Cus Franci
Published: October 2013

In this paper, optimization system based on the artificial neural networks (ANN) and particle swarm optimization (PSO) algorithm was developed for the optimization of machining parameters for turning operation. The optimization system integrates the neural network modeling of the objective function and particle swarm optimization of turning parameters. New neural network assisted PSO algorithm is explained in detail. An objective function based on maximum profit, minimum costs and maximum cutting quality in turning operation has been used. This paper also exhibits the efficiency of the proposed optimization over the genetic algorithms (GA), ant colony optimization (ACO) and simulated annealing (SA).
Development of Assisted Filtered Cathodic Vacuum Arc Deposition of Nano-Dispersed Multi-Layered Composite Coatings on Cutting Tools
Authors: Vereschaka Alexey Anatolevich
Published: October 2013

This paper presents the results of development and application of processes for modification of various properties of working surfaces of cutting tools by condensing vapor and ion flows in assisting impulse or constant exposure to high-energy ions. The paper shows features of the technology and equipment for the formation of wear-resistant components, which modify the structure and properties of working surfaces of various edge cutting tool types in a wide range of temperatures, in order to improve tool life and reliability. Various properties of the modifying components were studied, and their ability to improve the operational efficiency of different types of carbide cutting tools for cutting various materials was shown.
A Low-Cost pH Sensor Based on RuO2 Resistor Material
Authors: Manjakkal Libu , Cvejin Katarina , Kulawik Jan , Zaraska Krzysztof , Szwagierczak Dorota
Published: October 2013

Fresh water deficiency caused by climate change calls for employing novel measures to ensure safety of drinking water supply. Wireless sensor networks can be used for monitoring hydrological conditions across wide area, allowing flow forecasting and early detection of pollutants. While there are no fundamental technological obstacles to implementation of large area sensor networks, their feasibility is constrained by unit cost of sensing nodes. This paper describes a low-cost pH sensor, intended for use in fresh water monitoring. The sensor was fabricated in a standard thick film process, and an off-the-shelf resistive paste was used as a sensing material. For the fabrication of sensor, RuO2 resistive paste was screen printed on the alumina substrate with silver conducting layer. Test solutions with pH ranging from 2 to 10 were prepared from HCl or KOH solutions. The potential difference between reference and sensing electrode (electromotive force emf of an electrochemical cell) should be proportional to the pH of a solution according to the Nernst equation. The fabricated sensor exhibits Nernstian response to pH. Influence of storage conditions on sensing performance was also investigated.
Functions and Future Applications of F1 ATPase as Nanobioengine - Powering the Nanoworld!
Authors: Magdum Sandip S.
Published: October 2013

Recent nanotechnological revolution mandates astonishing imagination about future nanoworld. Nature has ability to create nanobiomolecules which can function in extraordinary way which can be used to produce nanohybrid systems. The opportunity to use such nanobiomolecules in combination of nanomechanical systems for development of novel nanohybrid systems for their various applications needs to explore in further nanotechnological development. F1 ATPase is a subunit of ATP synthase, which is one of the biomolecular structure works on the plasma membrane of the living cell. The reversible function of F1 ATPase gives a counterclockwise rotation of γ shaft by hydrolyzing ATP and the energy released in the form of rotational torque. This rotational torque of F1 ATPase can be used to power the functional movement of nanodevice. This feature article discusses comparisons of various biomolecular motors for their powering capacities, recent developments, presents new discoveries, experimentations on F1 ATPase and its novel imaginary futuristic applications where F1 ATPase could be used as nanobioengine for powering functional nanoworld.
Performance-based financing for monitoring and evaluation of health system in Cameroon
Authors: Njoumemi Zakariaou , Fadimatou Altine
Published: October 2013

Objective: To describe the context of, types of and approaches to monitoring and evaluation and the stakeholders’ perceptions of Performance-based financing (PBF) in Cameroon.Methods: This research used secondary data, both qualitative and quantitative, from the PBF monitoring and evaluation plan, reports and documents, and information from 380 qualitative interviews of stakeholders. Data was analysed using a systematic process of triangulation of responses in tabular form to assess the contribution of PBF towards strengthening the national system of monitoring and evaluation. Descriptive statistics were presented in form of frequencies.Results: The context of decentralisation and results-based management put monitoring and evaluation at the centre of public policy actions. Performance is measured in terms of effectiveness, efficiency, equity, accountability and transparency. The expected effect of PBF is not to reinforce the monitoring and evaluation system but to increase its performance. In conception, the design of PBF relies on substantial efforts of systematic monitoring and evaluation that can strengthen the national health system. The PBF brought changes to all the organisational systems of the supply of health services according to the monitoring and evaluation objectives, which were aligned to those of the national health system and management health information. Stakeholders were positive about the resulting performance of the central tool for monitoring and evaluation of PBF.Conclusion: Several types of monitoring and evaluation are conducted in the implementation of the PBF scheme, showing great potential to strengthen the national system through the harmonisation and standardisation of indicators and norms at all levels of the national health system pyramid.
Development and Validation of RP-LC Method for the Determination of Cinnarizine/Piracetam and Cinnarizine/Heptaminol Acefyllinate in Presence of Cinnarizine Reported Degradation Products
Authors: EL-Houssini Ola M. , Zawilla Nagwan H. , Mohammad Mohammad A.
Published: October 2013

Specific stability indicating reverse-phase liquid chromatography (RP-LC) assay method (SIAM) was developed for the determination of cinnarizine (Cinn)/piracetam (Pira) and cinnarizine (Cinn)/heptaminol acefyllinate (Hept) in the presence of the reported degradation products of Cinn. A C18column and gradient mobile phase was applied for good resolution of all peaks. The detection was achieved at 210 nm and 254 nm for Cinn/Pira and Cinn/Hept, respectively. The responses were linear over concentration ranges of 20-200, 20-1000 and 25-1000 μgmL−1for Cinn, Pira, and Hept respectively. The proposed method was validated for linearity, accuracy, repeatability, intermediate precision, and robustness via statistical analysis of the data. The method was shown to be precise, accurate, reproducible, sensitive, and selective for the analysis of Cinn/Pira and Cinn/Hept in laboratory prepared mixtures and in pharmaceutical formulations.
Treatment strategies in rheumatoid arthritis
Authors: Szekanecz Zoltán
Published: October 2013

In this editorial, the author goes through the consecutive steps of rheumatoid arthritis (RA) treatment. In brief, the recent European recommendations are presented, followed by some strategic points of methotrexate (MTX) therapy. The initiation, maintenance and switch of biological therapy are discussed. After remission or low disease activity (LDA) is reached, tapering or discontinuation of biologics may be considered. Finally, the author reviews the most relevant clinical and biological markers of personalized treatment.
Usefulness of clinical tests for assessing radicular and pseudoradicular components of pain in diagnosing sciatica – a pilot study
Authors: Skorupska Elżbieta , Bednarek Agata , Urna Magdalena , Lisiński Przemysław , Sobieska Magdalena , Samborski Włodzimierz
Published: October 2013

Cel pracy: Zróżnicowana i złożona etiologia bólu z okolicy lędźwiowo-krzyżowej z promieniowaniem do kończyny dolnej wzbudza ciągłe spory i kontrowersje wokół kwestii diagnozowania i leczenia tej grupy chorych. Pacjenci, u których występuje ból odcinka lędźwiowo--krzyżowego pleców z promieniowaniem do kończyny dolnej, są dzieleni na tych, u których dolegliwości mają charakter korzeniowy i pseudokorzeniowy. Brak jednoznacznych kryteriów różnicujących te dwa komponenty bólu utrudnia ustalenie pochodzenia tych objawów. Celem pracy było zbadanie, które testy diagnostyczne mogą być przydatne w ocenie lokalizacji bólu i udziału tkanek miękkich w patomechanizmie rwy kulszowej.

Materiał i metody: Badaniu poddano 50 chorych, u których stwierdzono objawy rwy kulszowej i przeprowadzono test Lasegue’a, skrzyżowany test Lasegue’a (xSLR), test Bragarda oraz pięć testów oceniających stawy krzyżowo-biodrowe (sacroiliac joints – SI): test Yeomana, test Patricka, test Menela, test wypchnięcia i test kolców.

Wyniki: Wyniki testu Lasegue'a i testu Bragarda wykazywały istotną korelację u pacjentów z przepukliną krążka. U wszystkich pacjentów ze zmianami degeneracyjnymi krążka międzykręgowego (disc bulging) wynik testu Bragarda był negatywny. Skrzyżowany objaw Lasegue’a był dodatni tylko u pacjentów z przepukliną jądra miażdżystego. U wszystkich pacjentów, u których dodatni był wynik skrzyżowanego testu Lasegue'a, także wyniki testu Bragarda były dodatnie. Ponadto u 98% badanych dodatni był przynajmniej jeden z pięciu testów oceniających staw krzyżowo-biodrowy, wynik dla czterech pozytywnych testów stwierdzono u 20% badanych.

Wnioski: Wyniki badania pozwalają stwierdzić, że przeprowadzanie jednocześnie testów Lasegue’a i Bragarda jest uzasadnione, ale niewystarczające do potwierdzenia korzeniowego charakteru bólu rwy kulszowej. Pacjenci, u których przewlekle występują objawy rwy kulszowej wiążące się z uwypukleniem krążka, powinni być również ocenieni pod kątem zajęcia stawów krzyżowo-biodrowych.
Der unternehmungslustige Ire Bernard Connor (1666–1698)
Authors: Keitel Wolfgang
Published: October 2013

Praca doktorska irlandzkiego lekarza Bernarda Connora (1666–1698) z Reims z 1693 r., w której jest opisany tułów mężczyzny z kośćmi zrośniętymi w jeden blok kostny z powodu spondylitis ankylosans [zesztywniającego zapalenia stawów kręgosłupa], powszechnie jest uważana za pierwsze doniesienie o odnalezieniu takiego szkieletu. Informację tę należy jednak postrzegać w kontekście wcześniejszych oraz kolejno pojawiających się podobnych obserwacji w niemieckiej, a zwłaszcza angielskiej literaturze, w której znaleziska takie są opisywane – chociażby w zbiorach anatomicznych, czy też w kontekście klinicznym w większości publikacji Charlesa Hiltona Fagge z 1877 r. Tym samym długo stosowany w Niemczech eponim „choroba Marie-Strümplla-Bechterewa” jest nadal kwestionowany. Bernard Connor jest jednak z innych jeszcze powodów: medycznych i historycznych, uważany za niezwykle interesującą osobistość schyłku XVII stulecia. Jego naukowo zorientowane pisma medyczne przysporzyły mu wrogów w Kościele. Przez kilka miesięcy przebywał w Polsce jako nadworny lekarz króla Jana III Sobieskiego. W swojej trzytomowej, wydanej także w języku niemieckim, historii Polski przedstawił bardzo poglądowo ówczesne stosunki polityczne i społeczne, ale także medycynę kraju, którą postrzegał jeszcze jako bardzo zacofaną. W przeciwieństwie do tego plasują się wzorcowe w skali europejskiej osiągnięcia polskiej reumatologii u schyłku XX wieku, przedstawione na przykładzie kilku wybitnych osobistości.
Ray tracing model of the auroral kilometric radiation generation in the 3-D plasma cavity
Authors: Burinskaya T. M.
Published: October 2013

Abstract. Propagation and amplification of the auroral kilometric radiation (AKR) in a three-dimensional plasma cavity is investigated using the approximation of the geometrical optics, and taking into account both the slightly relativistic electrons propagating inside a cavity and the background cold electrons. It is shown that the global magnetic field inhomogeneity plays a key role in a wave escape from a thin plasma cavity. The main contribution to the AKR spectrum is made by waves initially generated with the component of group velocity directed to the Earth and with the optimum relationship between the wave vector components, controlling the value of the linear grow rate and duration of the ray lifetime inside a source.