bluuebunny/crossref_metadata_2025 huggingface dataset:
The Carnegie-Chicago Hubble Program. II. The Distance to IC 1613: The Tip of the Red Giant Branch and RR Lyrae Period–luminosity Relations*
Authors: Hatt Dylan , Beaton Rachael L. , Freedman Wendy L. , Madore Barry F. , Jang In-Sung , Hoyt Taylor J. , Lee Myung Gyoon , Monson Andrew J. , Rich Jeffrey A. , Scowcroft Victoria , Seibert Mark
Published: August 2017

IC 1613 is an isolated dwarf galaxy within the Local Group. Low foreground and internal extinction, low metallicity, and low crowding make it an invaluable testbed for the calibration of the local distance ladder. We present new, high-fidelity distance estimates to IC 1613 via its Tip of the Red Giant Branch (TRGB) and its RR Lyrae (RRL) variables as part of the Carnegie-Chicago Hubble Program, which seeks an alternate local route to H
0 using Population II stars. We have measured a TRGB magnitude

mag using wide-field observations obtained from the IMACS camera on the Magellan-Baade telescope. We have further constructed optical and near-infrared RRL light curves using archival BI- and new H-band observations from the ACS/WFC and WFC3/IR instruments on board the Hubble Space Telescope (HST). In advance of future Gaia data releases, we set provisional values for the TRGB luminosity via the Large Magellanic Cloud and Galactic RRL zero-points via HST parallaxes. We find corresponding true distance moduli

and

mag. We compare our results to a body of recent publications on IC 1613 and find no statistically significant difference between the distances derived from Population I and II stars.
Galaxy Zoo: Major Galaxy Mergers Are Not a Significant Quenching Pathway*
Authors: Weigel Anna K. , Schawinski Kevin , Caplar Neven , Carpineti Alfredo , Hart Ross E. , Kaviraj Sugata , Keel William C. , Kruk Sandor J. , Lintott Chris J. , Nichol Robert C. , Simmons Brooke D. , Smethurst Rebecca J.
Published: August 2017

We use stellar mass functions to study the properties and the significance of quenching through major galaxy mergers. In addition to SDSS DR7 and Galaxy Zoo 1 data, we use samples of visually selected major galaxy mergers and post-merger galaxies. We determine the stellar mass functions of the stages that we would expect major-merger-quenched galaxies to pass through on their way from the blue cloud to the red sequence: (1) major merger, (2) post-merger, (3) blue early type, (4) green early type, and (5) red early type. Based on their similar mass function shapes, we conclude that major mergers are likely to form an evolutionary sequence from star formation to quiescence via quenching. Relative to all blue galaxies, the major-merger fraction increases as a function of stellar mass. Major-merger quenching is inconsistent with the mass and environment quenching model. At

, major-merger-quenched galaxies are unlikely to constitute the majority of galaxies that transition through the green valley. Furthermore, between

, major-merger-quenched galaxies account for 1%–5% of all quenched galaxies at a given stellar mass. Major galaxy mergers are therefore not a significant quenching pathway, neither at

nor within the last 5 Gyr. The majority of red galaxies must have been quenched through an alternative quenching mechanism that causes a slow blue to red evolution.
Very Large Array Multiband Monitoring Observations of M31*
Authors: Yang Yang , Li Zhiyuan , Sjouwerman Loránt O. , Yuan Feng , Shen Zhi-Qiang
Published: August 2017

The Andromeda galaxy (M31) hosts one of the nearest and most quiescent supermassive black holes, which provides a rare, but promising opportunity for studying the physics of black hole accretion at the lowest state. We have conducted a multifrequency, multi-epoch observing campaign, using the Karl G. Jansky Very Large Array (VLA) in its extended configurations in 2011–2012, to advance our knowledge of the still poorly known radio properties of M31*. For the first time, we detect M31* at 10, 15, and 20 GHz and measure its spectral index, α ≈ −0.45 ± 0.08 (S
ν
 ∝ ν

α
), over the frequency range of 5–20 GHz. The relatively steep spectrum suggests that the observed radio flux is dominated by the optically thin part of a putative jet, which is located at no more than a few thousand Schwarzschild radii from the black hole. On the other hand, our sensitive radio images show little evidence for an extended component, perhaps except for several parsec-scale “plumes,” the nature of which remains unclear. Our data also reveal significant (a few tens of percent) flux variation of M31* at 6 GHz, on timescales of hours to days. Furthermore, a curious decrease of the mean flux density, by ∼50%, is found between VLA observations taken during 2002–2005 and our new observations, which might be associated with a substantial increase in the mean X-ray flux of M31* starting in 2006.
Pulsar Wind Bubble Blowout from a Supernova
Authors: Blondin John M. , Chevalier Roger A.
Published: August 2017

For pulsars born in supernovae, the expansion of the shocked pulsar wind nebula is initially in the freely expanding ejecta of the supernova. While the nebula is in the inner flat part of the ejecta density profile, the swept-up, accelerating shell is subject to the Rayleigh–Taylor instability. We carried out two- and three-dimensional simulations showing that the instability gives rise to filamentary structure during this initial phase but does not greatly change the dynamics of the expanding shell. The flow is effectively self-similar. If the shell is powered into the outer steep part of the density profile, the shell is subject to a robust Rayleigh–Taylor instability in which the shell is fragmented and the shocked pulsar wind breaks out through the shell. The flow is not self-similar in this phase. For a wind nebula to reach this phase requires that the deposited pulsar energy be greater than the supernova energy, or that the initial pulsar period be in the ms range for a typical 1051 erg supernova. These conditions are satisfied by some magnetar models for Type I superluminous supernovae. We also consider the Crab Nebula, which may be associated with a low energy supernova for which this scenario applies.
Capilla, en Colorado
Authors: Hunter James M.
Published: August 2017

Esta pequeña capilla, de aspecto rústico, muestra al exterior una textura muy diversa en las dos zonas que claramente presenta: una parte de fábrica de mampostería de piedra arenisca blanquecina —en despiece de prolongadas llagas horizontales e irregulares tendeles, —asimétrica de la otra, que está formada por una retícula de madera rojiza de abeto, trazada entre los pilares rítmicamente dispuestos, que sustentan los pares de la cubierta.
Iglesia, en Coventry
Authors: Levender - Twentyman - Percy Arquitectos
Published: August 2017

La iglesia de San Nicolás, en Coventry, como otras edificadas en naciones afectadas por la última conflagración mundial, se ha levantado en el solar que ocupaba una del siglo pasado, destruida por los bombardeos. El terreno es arcilloso y presenta un ligero declive hacia la carretera, lo que proporciona un desnivel favorablemente ventajoso para destacar un edificio como éste, de tipo representativo, aparte —naturalmente— de la verticalidad acusada de la torre.
Determining Stress-Strain Behavior of Zr60Cu10Al15Ni15 Bulk Metallic Glass Using Object Oriented Finite Element Analysis
Authors: Patel Ketul Arvindbhai , Karthikeyan Ganesh R. , Vincent S.
Published: August 2017

Determining mechanical properties of Bulk Metallic Glasses (BMGs) requires synthesizing of the alloys in bulk form. However obtaining metallic glass in bulk form is quite challenging due to its tendency towards crystallization. In such circumstances it is beneficial to determine the mechanical properties of materials using finite elemental analysis of microstructures. Thus, in the present investigation, using Object Oriented Finite Element Analysis (OOF2) software package, Stress-Strain analysis has been carried out on Zr60Cu10Al15Ni15 BMG to determine such mechanical properties. Specimen of Zr60Cu10Al15Ni15 BMG exhibiting three microstructurally distinct regions amorphous, partial crystalline and crystalline regions was used for this analysis. The Stress-Strain relationship have been estimated for each of the three distinct phases and the results are validated by determining the Modulus of Elasticity for all the phases and comparing it with the available experimental results from Nano-indentation test.
Luminescence White Light from CdTe/ZnSe Core/Shell Nanocrystals System
Authors: Kadim Akeel M.
Published: August 2017

The white light generation mechanism was explained depending on mixing colors from the illuminated CdTe/ZnSe core/shell nanocrystals. The color mixed in CdTe/ZnSe core/shell system were used to generate intense white light when illuminated by InGaN/GaN UV LED (λ=360 nm) the core/shell system tuned the chromaticity coordinates to (0.30, 0.32) and increased the intensity of the emitted white light. This improvement was attributed to the overlap of emission with the photoluminescence (PL) spectrum of CdTe/ZnSe core/shell which leads to a cold white light generation.
XRD and FTIR Studies of Nanocrystalline Cellulose from Water Hyacinth (Eichornia crassipes) Fiber
Authors: Asrofi Mochamad , Abral Hairul , Kasim Anwar , Pratoto Adjar
Published: August 2017

The isolation and characterization of nanocrystalline cellulose (NCC) from water hyacinth (WH) fibers were carried out. There are two treatments to obtain NCC from WH fibers by chemical and mechanical treatments. The chemical treatment involved alkalization with NaOH 25% in a highly-pressured tube, acid hydrolysis with 5M HCl, and bleaching with (NaClO2:CH3COOH) in ratio 5:2. The mechanical treatment was performed by using ultrasonic homogenizing at 12000 Rpm for 2 h. The morphological surface was observed by Transmission Electron Microscopy (TEM). TEM reported that the size of NCC was 10–40 nm. Crystallinity index and functional group analysis of the NCC WH fibers were also examined using X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. XRD reported that the crystallinity index increased significantly after chemical and mechanical treatment due to the presents of crystalline area in the WH fibers. The crystallinity index of raw fiber, digester, bleaching, and ultrasonic homogenizing were 7%, 68%, 69%, and 73% respectively. The content cellulose of final product was 68% as measured by the chemical composition test. Meanwhile, FTIR reported that WH fibers after being given chemical treatment lead the functional group change due to removal hemicellulose and lignin. The result of XRD and FTIR were indicated that the sample of NCC WH fibers presents the structure of cellulose crystal type I.
On Time Step in the Molecular Dynamics (MD) Simulation of Nanomachining
Authors: Oluwajobi Akinjide O. , Chen Xun
Published: August 2017

The study of nanoscale machining phenomena and processes are effectively been carried out by using the molecular dynamics (MD) simulation. The MD provides explanation of material behaviour that are difficult to observe or even impossible through experiments. To carry out reliable simulations, the method depends on critical issues, which include the choice of appropriate interatomic potentials and the integration time step. The selection of the timestep in the MD simulation of nanomachining is the major focus of this investigation. A too low timestep would be computationally expensive and also a too high timestep would cause chaotic behaviour in the simulation. Computational experiments were conducted to check for the range of timestep that is appropriate for the simulation of nanomachining of copper. It was observed from the total energy variations, that time step in the range of 0.1 to 0.4 fs could be used to procure stable simulations in copper, for the configuation employed.
Experimental Investigation of Effect of the Laser-Assisted Finish Turning of Ti-6Al-4V Alloy on Machinability Indicators
Authors: Habrat Witold F.
Published: August 2017

In this paper, the experimental studies of the finish turning of Ti-6Al-4V titanium alloy with the laser-assisted machining were described. For the tests, a cemented carbide tool was used. The influence of the laser heating on the microstructure of Ti-6Al-4V titanium alloy for kinematics corresponding with the turning process was determined. For a laser scanning rate of 80 m/min and laser power 1200W, the maximum depth of the melted zone was about 50 μm. The beneficial effect of laser assisted machining on components of the cutting force was established. For a cutting speed of 80 m/min, feed rate 0.1 mm/rev, depth of cut 0.25 mm and laser power 1200 W, over 60% reduction of the tangential components of cutting force was observed. The chip-breaking effect for the conventional and the laser-assisted processes was determined. Roughness parameters of the surface after the conventional and laser-assisted turning are compared.
Laser Beam Milling of Alumina Ceramics - The Impact on Material Removal Efficiency and Machined Surface Morphology
Authors: Šugár Peter , Frnčík Martin , Šugárová Jana , Sahul Miroslav
Published: August 2017

Laser machining is one of the most widely used advanced noncontact machining processes used for creating new surfaces, structures, cavities and also complex electro-mechanical devices, usually with very small dimensions, by laser radiation. It is the process in which the material’s thermophysical properties rather than mechanical properties determine the machinability. Design of process parameters is highly critical for successful material removal and high machine surface quality. In the paper the laser beam milling is experimentally studied applying the nanosecond pulse fibre laser and alumina ceramic as working material. The influence of pulse energy, pulse repetition rate, scanning speed and tracks displacement on material removal efficiency and the quality of machined surface is reported.
Development of a Polishing Jig for Machining Centres
Authors: Mitropoulos Theodore , Avrampos Panagiotis , Vosniakos George Christopher
Published: August 2017

A polishing jig was designed and manufactured to enable polishing of metal surfaces on CNC machining centres, on which these surfaces are normally finish-machined first. The jig accommodates ring-type tools rotated by a high speed spindle, rendering the machining centre’s own spindle redundant. Passive control of the polishing force is materialized through the machining centre’s Z axis displacement acting on the jig’s springs. Jig design is explained laying special emphasis on calculations pertaining to the springs employed. Functionality of the jig was tested with trochoidal polishing paths and typical results are presented in terms of peak-to-valley surface roughness attained, verifying that a uniform ‘mirror range’ finish is achievable.
The Effect of Changes in Feed Rate on Surface Integrity during Nickel Coating Grinding
Authors: Marek Martin , Novák Martin
Published: August 2017

Grinding is an important and very frequently used technology, allowing for significant gains in surface integrity. Products which have undergone surface treatment are often used in engineering. The required surface quality after grinding is one of the most important parameters. Nickel coatings as protection against corrosion are used, erosion, abrasion and as a material for the renovation of worn-out parts. This paper discusses the change of cutting conditions when samples were ground. The surface of the samples was treated with galvanically applied nickel. The data shows what level of surface roughness is achieved when choosing different cutting conditions. The results were evaluated on the basis of a comparison of the parameters of roughness. The input parameters were chosen on the basis of the practice, which was in the area carried out.
The Influence of Cutting Conditions on Surface Roughness during Steel 100Cr6 Grinding
Authors: Novák Martin , Naprstkova Natasa
Published: August 2017

Machining of tool steels is often an important used technology. Products made from these materials are often used in mechanical engineering, and quality of workpiece surface roughness after machining respective grinding is one of the important parameters that to us speak about the quality of the machining process. The paper deals with the influence of cutting conditions when grinding bearing steel 100Cr (EN ISO) on machined surface roughness. This steel belongs to a group of bearing steels.
A Method for the Determination of Theoretical Roughness in Face Milling Considering the Run-Out of the Inserts
Authors: Felho Csaba , Kundrák János
Published: August 2017

A method is introduced for determining theoretical values of roughness characteristics of surfaces generated by tools having a defined edge geometry. The method is based on the CAD modelling of the theoretical cut surface, and can be used to model practically any complex tool geometry. In application to rotating tools (e.g. face milling), besides the variety of tool designs, the setting accuracy was also taken into consideration during the determination of theoretical values due to the simultaneous cutting of more than one edge. It will be demonstrated that in addition to the determination of 2D roughness parameters, the method is suitable to determine the 3D roughness parameters as the surface topography can be more accurately described with these characteristics. Experimental data is shown to validate of the extended modelling and calculation method.
Stress Analysis of the Rotating Circular Saw Blade
Authors: Bílek Ondřej , Kovařík Martin
Published: August 2017

The article deals with the determination of parameters of longitudinal wood cutting by circular saw blade and construction of the cutting tool. A computational model was chosen to determine stress of the rotating circular saw blade. Stress analysis revealed that maximal stress caused by the temperature gradient was approximately ten times higher than the maximum stress extrapolated from centrifugal forces. In this work were determined the critical speed of the circular saw blade and the power needed to spin. The contribution of this work is the algorithm of the power required for longitudinal wood cutting wood by a circular saw blade, which allows optimal machine tool proposal. Moreover, the calculated state of stress is compared to the FEM model.
A Study of Explicit Numerical Simulations in Orthogonal Metal Cutting
Authors: Kaselouris Evaggelos , Papadoulis Theodoros , Variantza Elenh , Baroutsos Andreas , Dimitriou Vasilios
Published: August 2017

The capability of the explicit numerical methods to simulate accurately the real cutting process is investigated in this research work. Smoothed particle hydrodynamics - SPH, classical Lagrangian finite element method - FEM and Multi-Material Arbitrary Lagrangian Eulerian - ALE methods are chosen for the modeling and simulation of the orthogonal metal cutting process of AISI H13 in LS-DYNA. The cutting tool is modeled as a rigid FEM body that incrementally penetrates into the flexible deformable workpiece. At each numerical model, the dynamic elastoplastic behavior of the workpiece material is investigated by taking into account the Johnson-Cook (J-C) constitutive strength material model. The influence of the J-C parameter values found in literature to the models is explored. The obtained numerical SPH, FEM and ALE results of the estimated cutting and thrust forces, stress, plastic strain and thermal distributions are compared with results found in the literature. This comparison, leads to valuable conclusions for the performance of the three methods, concerning the approximation accuracy, model development complexity and computational time demands. Based on these conclusions the SPH method is chosen to simulate the experimentally performed orthogonal cut of AISI 1045. The obtained SPH numerical results outline its advantages among the other explicit simulation methods.
Numerical Investigation of Mechanical Induced Stress during Precision End Milling Hardened Tool Steel
Authors: Reimer Andreas , Fitzpatrick Stephen , Luo Xi Chun , Zhao Jie
Published: August 2017

Hardened tool steels are widely used materials for forming dies, due to their increased strength and hardness. However, their machinability is very poor, due to the high hardness of the material, which leads to high cutting forces and premature failure of the cutting tools. This is also associated with machining induced tensile stresses within the work piece. No full factorial design has been performed when end milling tool steel, due to the high associated costs. Instead of physical experiments, numerical models are commonly used to save cost and time. However, most of the recent research focus was only on 2D FE-Models. 2D model can be used for simulation of some simplified process, however, the results are not sufficient for accurate prediction. Therefore, a 3D FE-model of a precision end milling process with a two-flute ball nose cutter were established in this paper, in order to build a multi cutting edge model. In the FE-Model, a subroutine was implemented to model work piece hardening during the cutting process. The subroutine realised an accurate prediction of the residual stress and cutting forces. In addition, a material removal criterion was developed and implemented. The influence of cutting parameters on cutting force for end milling H13 tool steel was studied, through full factorial numerical simulations, to evaluate the effectiveness of this FEA model. Subsequently, after validation of the FEM model through machining trials, empirical models were developed for predicting cutting forces and residual stress. The cutting parameters evaluated were cutting speed, feed rate and depth of cut. In summary, it was found that the simulation and the experiments had a good agreement on the value and trend of the residual stress. The FEM model can be effectively used to predict residual stress in the machined surface.
Development of ANFIS Model for Flow Forming of Solution Annealed H30 Aluminium Tubes
Authors: Podder Bikramjit , Banerjee Prabas , Kumar K. Ramesh , Hui Nirmal Baran
Published: August 2017

Modeling of the cold flow forming process for manufacturing of tube shaped solution annealed H30 Aluminum alloy has been considered in this present study. Three inputs (feed-speed ratio, roller in-feed and roller axial stagger) and three outputs viz. spring back, ovality and internal diameter have been considered for the present study.. Adaptive network-based fuzzy inference system (ANFIS) in Matlab platform has used for modeling purposes and its performance is compared with regression model. ANFIS has completely outperformed the regression models. Percentage accuracy in predicting all the three responses are found to be very high with ANFIS models. Prediction of ovality against the test data using regression analysis is found to be extremely erroneous. It indicates that additional process parameters are involved in predicting ovality which are not captured during the experimentation.
A Heuristic Approach to Design Discrete Fractional Order Integrators without Using s-to-z Transform
Authors: Mahata Shibendu , Saha Suman Kumar , Kar Rajib , Mandal Durbadal , Banerjee Nilotpal
Published: August 2017

In this paper, a heuristic optimization technique called Harmony Search Algorithm (HSA) is efficiently employed to design Infinite Impulse Response (IIR) Discrete Fractional Order Integrators (DFOIs). Unlike the methods reported in the literature, no discretization (s-to-z transform) operator is necessary to obtain the DFOIs by using the proposed approach. To investigate the design efficiency, the HSA-based DFOIs have been evaluated against the designs based on Real coded Genetic Algorithm (RGA), Particle Swarm Optimization (PSO), and Differential Evolution (DE) using different frequency response error metrics. The reliability in the performance of the proposed DFOIs are extensively investigated by conducting various statistical tests. Comparison of fitness convergence demonstrates that HSA achieves the near global optimal solution in the least number of iterations. Thus, HSA exhibits superior computational efficiency in solving this multimodal optimization problem. The proposed DFOIs also outperform the reported designs.
Discrete Non-Integer Order Differentiator Models Using Moth-Flame Optimization Algorithm
Authors: Mahata Shibendu , Saha Suman Kumar , Kar Rajib , Mandal Durbadal
Published: August 2017

Discrete rational approximation models to the non-integer order differentiator sλ, where λ ε (0, 1), using Moth-Flame Optimization (MFO) algorithm is proposed in this paper. The proposed metaheuristic optimization approach used to design the discrete non-integer order differentiators (DNODs) does not employ any s-to-z domain mapping function to perform the discretization operation. Frequency domain characteristics of DNODs, solution reliability, and algorithm convergence performances are investigated among MFO and an advanced evolutionary algorithm called Particle Swarm Optimization with adaptive inertia weight (PSO-w). Results demonstrate the effectiveness of MFO in outperforming PSO-w in solving this non-linear and multimodal optimization problem. The proposed DNODs also exhibit better performance in comparison with the designs based on techniques such as Nelder-Mead Simplex algorithm and Cuckoo Search Algorithm published in recent literature.
Recent Developments in Desktop-Sized Machine Tools
Authors: Aurich Jan C. , Müller Christopher , Bohley Martin , Arrabiyeh Peter , Kirsch Benjamin
Published: August 2017

The miniaturization of components and the functionalization via micro structures demands for flexible and economic manufacturing processes. Micro machining, i.e. micro milling and micro grinding can meet these requirements. In this paper, desktop-sized machine tools and their components that were developed at our institute are presented. With those machine tools, micro tools can be machined and used in one clamping, allowing for increased machining quality. Grooves milled with such machine tools achieve a bottom surface roughness below 10 nanometer.
Advanced Metrology and Intelligent Quality Automation for Industry 4.0-Based Precision Manufacturing Systems
Authors: Durakbasa Numan M. , Bauer Jorge , Poszvek Günther
Published: August 2017

Intelligence is an essential feature of future development and production systems, and intelligent production is a major component of future business. To meet market demands in present and future global industrial world, manufacturing enterprises of any kind and any size must be flexible and agile enough to respond quickly to product demand changes also according technological developments especially in the field of precision engineering at micro/nanoand pico scale production. With support of AI and modern IT it is possible to realise modern cost-effective customer-driven design and manufacturing taking into account the importance and basic role of modern Integrated Management Systems - IMS and intelligent advanced metrology.This new concept can be developed on the basis of intelligent production technologies and integrated systems as well as extensive use of the IT, AI, simulation, quality autonomation, robotics, advanced metrology and advanced engineering data exchange techniques. Moreover by utilizing advanced information analytics, networked intelligent machines and instruments will be able to perform more efficiently, collaboratively and sustainably, that makes possible an agile and optimal industrial production in any kind of industry and especially in up-to-date SMEs towards Industry 4.0.
Internet of Things and Industrial Applications for Precision Machining
Authors: Benardos Panorios G. , Vosniakos George Christopher
Published: August 2017

The Internet of Things (IoT) can be regarded as an attempt to bring together the physical and the digital world by using devices for seamlessly exchanging and processing information that can be used anywhere, anytime. For industrial automation and manufacturing, the Industrial Internet of Things (IIoT) is regarded as the next step of industrial revolution that promises a step-change in productivity and operational efficiency.Precision machining is a field that has received a lot of research interest as it deals with phenomena and underlying mechanisms that are very complex and highly interacting. As the requirements and demand for products of high quality and tolerances that must be produced with shorter lead times are increasing, innovative approaches and methodologies need to be developed to compensate and IIoT offers an appropriate platform. This paper aims to present an overview of IIoT, investigate potential industrial applications for precision machining and predict future trends.
Sensor Networks for Smart Manufacturing Processes
Authors: Konyha József , Bányai Tamás
Published: August 2017

Each factory and manufacturing plant needs a flexible and reliable in-plant resource supply to serve production processes efficiently. Manufacturing systems are composed of several numbers of elements, workstations, machines and logistics resources. Production line is a complex system because of the complicated manufacturing process, multiple types, high machining difficulty and many special processes in it. In the Industry 4.0 based on smart manufacturing, it is essential to support the processes with intelligent sensor networks. In this article, we give a brief overview about sensors often used in manufacturing processes. Sensor networks generate a massive and increasing amount of data that needs to be processed. Computationally intensive algorithms are used for the data processing (image, voice and signal processing, different classification functions, numeric optimization routines). Finally, we discuss how GPGPU can improve the real-time processing of data generated by intelligent sensor networks.
Cost Reduction of Manufacturing and Assembly - Case Study
Authors: Sarka Ferenc
Published: August 2017

In this paper the results of an industrial-based examination (client: Electrolux) is described. The task of the examination was to reduce manufacturing and assembling costs of some products (vacuum cleaners, refrigerators and freezers). In the beginning of this paper a few cost reduction philosophies (TPS, Lean) are shortly introduced. Based on the carried out work, the intervention options were classified into four groups. The paper gives examples for each group. The client required that the quality of the devices should not deteriorate as a result of the interventions. The client requested an “outsider” to explore cost-cutting opportunities. The client has provided us with detailed technical documentation of the equipment and one piece of each type of products (11 different) and we could also see the production of the products in the factory. The main purpose of the work is to show what kind of cost saving opportunities can find an “outsider” in common products.
Temperature Distribution in the Machining Zone during the Turning of a Shaft Made of the AMS5643 Steel
Authors: Ślusarczyk Łukasz
Published: August 2017

The paper presents the results of laboratory measurement of temperature in the machining zone during the straight turning of a shaft made of the AMS 5643 steel. The machining trials were recorded using the FLIR 620 thermographic camera, and the ThermaCam Researcher software was used to archive and analyse the measurement results. The experimental test plan for varying machining parameters (vc, ap, f) was developed using the Taguchi method, and the ANOVA was used for statistical processing of results. The experiment involved nine trials with a coated insert and nine trials with an uncoated insert. The obtained results will be used to improve the cutting process simulation model.
Experimental Study on Micro-Machinability of Hardened Tool Steel in Profile Micro-Milling
Authors: Sredanovic Branislav , Globocki Lakic Gordana
Published: August 2017

Components miniaturization in industry leads to intensive research and development of efficient micro-technologies through research of different production processes, machines and tools. This paper presents experimental research on machinability of inclined surfaces on hardened steel workpieces with long-neck micro-end-ball mills. Workpiece is hardened AISI D2 tool steel (X155CrVMo-5). Micro-parts of this material is usually produced by non-conventional technologies such as electro-discharge machining (EDM) and laser beam machining (LBM), that allows machining of 2D or simple 3D structures. The effects of geometrical and cutting parameters on output machinability parameters in ball micro-milling were evaluated. Analysis of tool deflection, surface roughness and tool wedge wear was performed, in order to obtain the recommended cutting parameters for more precise, accurate and quality of micro-parts.
Selective Chemical and Biological Metal Recovery from Cu-Rich Bioleaching Solutions
Authors: Hedrich Sabrina , Kermer René , Aubel Tim , Martin Mirko , Schippers Axel , Johnson D. Barrie , Janneck Eberhard
Published: August 2017

Pregnant leach solutions (PLS) resulting from bioleaching of copper concentrate from Kupferschiefer are characterized by low pH and high concentrations of Fe, Cu, Zn as well as significant amounts of Ni and Co. In order to recover the valuable metals for further processing, chemical methods and a novel biological-induced technique that promotes selective metal recovery and sulfate removal from acidic liquors were applied and a process scheme was developed.
Bioleaching of Tailings Resulting from Benefication of Polymetallic Ores for Recovery of Valuable Metals
Authors: Vardanyan Narine S. , Sevoyan Garegin G. , Vardanyan Arevik K.
Published: August 2017

Concentrated tailings samples resulting from the benefication of polymetallic ores (Armenia) were exposed to bioleaching in order to recover non-ferrous and precious metals. Bioleaching of concentrated tailings samples was performed by the natural microbial consortium of drainage water. It was shown that the extent of extraction of metals from two samples of concentrated tailings by the natural microbial consortium reached 55, 56% and 63, 73% for copper and zinc, respectively. However, the application of the natural microbial consortium together with an iron- oxidizing Acidithiobacillus sp.13Zn resulted in an increase of extraction of metals from concentrated tailings to 70 - 93% for Cu and 75 - 90% for Zn. Thus, to increase the recovery of non-ferrous and precious metals, the use of a natural microbial consortium of drainage water combined with an iron- and sulfur- oxidizing Acidithiobacillus sp.13Znis proposed.
Production Development of Olimpiadinskoe Gold Processing Plant through BIONORD® Technology Processing
Authors: Belyi Aleksandr , Chernov Dmitriy , Solopova Natalia
Published: August 2017

The first production shop in Russia of refractory gold ores biooxidation using chemoautotrophic microorganisms association was launched in 2001 at Olimpiada gold recovery plant. The shop was designed for treatment of 3 million tons of Olimpiada deposit “Vostochniy” pit primary sulphide ore per year. In 2007 the BIO-2 shop designed for treatment of 5 million tons of primary sulphide ore was launched. Total capacity of the two bio-processing unit is 8 million tons of sulphide ores per year. A more advanced concept of BIO-3 shop was developed based on industrial operation and performance analysis of BIO-1 and BIO-2. The concept was based on biooxidation process automatisation with displaying control and managing parameters of the process on the monitors in control room. This allows to keep main process parameters within the specified limits and maintain process in a stable high-performance state. Installation of the automatisation systems in BIO-1 and BIO-2 shops allowed increasing the throughput of all flotation concentrate treatment shops from 870 t/day to 1200-1300 t/day. This led to production of more than 26 tons of gold in 2016. Currently JSC “Polyus” is copyright holder of patented refractory gold sulphide ores concentrate treatment technology, patented microbial association carrying out the process, and the technology itself is protected by the trademark "BIONORD".
Heap Biooxidation of Gold-Sulphide and Polymetallic Ores and Tailings
Authors: Epiforov Alexander V. , Seleznev Aleksey N. , Emelyanov Yuriy Ye. , Balikov Stanislav V. , Shketova Lyudmila Ye. , Kopylova Natalia V.
Published: August 2017

Heap biooxidation is the most economic option of treating processing plants tailings and refractory ores containing non-ferrous and precious metals and sulphides.Pyrite tailings of copper ore processing (Sample 1), tailings of sulphide copper-nickel ore processing (Sample 2) and double refractory gold-bearing ore (Sample 3) were studied.Autotrophic microorganisms Acidithiobacillusthiooxidans and Acidithiobacillusferrooxidans were used for the tests. The duration of heap biooxidation tests for Samples 1, 2 and 3 was 6, 10 and 16 months, respectively. The rates of copper and zinc recovery into solution during heap biooxidation of Sample 1 were 68% and 71%, respectively; the rates of copper and nickel recovery from Sample 2 were 50% and 75%, respectively. Base metals were extracted from solution to selective high-grade concentrates after biooxidation.Biooxidation tailings of Samples 1 and 3 were leached using an alkaline sodium cyanide solution. The recovery of gold from Sample 1 and Sample 2 was 65% and 85%, respectively.
Biogenic Hydrogen Sulfide for Cyanide Regeneration in Solutions during Cupriferous Gold Ores Processing
Authors: Faiberg Anna A. , Mikhailova Aleksandra N. , Dementiev Vladimir E. , Gudkov Sergey S.
Published: August 2017

An optimal approach to the problem of cupriferous gold ores hydrometallurgical processing is the recycling of process solutions after copper recovery and regeneration of cyanide bound in complexes. The study focuses on the copper-cyanide solutions processing technology using biogenic hydrogen sulfide for copper recovery in the form of сhalcocite, and cyanide regeneration. The strains of anaerobic sulfidogenic thermophilic microorganisms Desulfurella acetivorans and Desulfurella Kamchatkensis were used for producing hydrogen sulfide. The studies on copper precipitation and cyanide regeneration were conducted on copper-cyanide process solutions which were obtained during cyanidation of refractory cupriferous gold-bearing flotation concentrates from one of the deposits in the South Ural (Russia). Ten cycles of "Cyanidation-Regeneration" were carried out in total. The copper recovery was 86–96 %; the cyanide regeneration obtained 96 %. On an average 8.9 kg of sodium cyanide and 4.6 kg of copper sulfide were recovered from 1 m3 of solution. The sodium cyanide consumption decreased from 25.0 kg/t to 6.0 kg/t without reducing gold recovery during the CIL (carbon-in-leach) recycling process. The gold recovery was the same 63–68 %.
Investigation of Intermediates Evolutions during Bornite Bioleaching by Mesophilic Mixed Bacteria
Authors: Wang Xing Xing , Hu Ming Hao , Huang Xiao Tao , Liao Rui , Zhao Hong Bo , Hong Mao Xin , Wang Jun
Published: August 2017

In this study, bioleaching experiments, X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) were conducted to investigate the intermediates and surface species of bornite leached by mesophilic mixed bacteria of Leptospirillum. ferriphilum and Acidithiobacillus. caldus. Bioleaching experiments results showed that the mixed bacteria induced higher redox potential and significantly increased the copper extractions. In the presence of mesophilic mixed bacteria, bornite bioleaching was not inhibited by jarosite and S8. The evolution of intermediates during bornite dissolution was proposed: Cu5FeS4→ Cu9Fe9S16→CuFe2S3→CuS→Cu2+, the presence of mesophilic mixed bacteria accelerated the dissolution process. XPS spectra showed that the Cu was existed as Cu(I) species in different period, and confirmed that the presence of polysulfide and jarosite.
Bioelectrochemical Leaching of Copper Sulfide Minerals
Authors: Ranjbar Mohammad , Esmailbagi Mohammadreza , Schaffie Mahin
Published: August 2017

The objective of this study is to improve the understanding of copper sulfides dissolution and to use this knowledge for optimization of process parameters for commercial application of electrochemical bioleaching of chalcopyrite concentrates in stirred bioreactors. From the results of this study, the importance of the oxidation reduction potential (ORP) on the catalytic interaction between chalcopyrite and pyrite can be pointed out as the main parameters for successful bioprocessing of chalcopyrite concentrates. Under these conditions, the optimization of the average particle size of feed (D80) and adjusting the ORP in the range between 400-450 mV are important criteria for increasing the electrochemical bioleaching rate of chalcopyrite concentrates. It seems that the main reason for the increased copper recovery could be the control and prevention of chalcopyrite passivation resulting from improved galvanic interaction between copper sulfide minerals, here especially chalcopyrite and pyrite in the selected ORP range and the right particle size distribution of feed. At optimum conditions, the copper extraction from chalcopyrite flotation concentrate during 7 days of continuous electrochemical bioleaching operations in stirred tanks was about 95%, which should be high enough to justify the process economically.
Influence of Citrate on Metal Dissolution and Respiration Rate of Microbial Leaching Cultures
Authors: Giebner Fabian , Rolle Jessica , Helmich Joahnnes , Schlömann Michael , Schopf Simone
Published: August 2017

The application of acidophilic iron oxidizing bacteria is an established technique in tank and heap leaching of mainly sulfidic minerals. Even though bioleaching is broadly studied, there are still several issues to solve. Especially, the formation of iron precipitates, leading to co-precipitation of valuable metals, as well as the inhibition due to coating, considerably decrease the leaching efficiency. Consequently, the addition of chelating agents should result in an increased dissolution rate.However, organic acids, which have chelating characteristics, are generally regarded as highly toxic for leaching bacteria. Nonetheless, we found that both the addition of sodium citrate and citric acid leads to an increased iron oxidation rate of 42% and 84%, respectively, compared to standard culture medium without citrate. Chemical leaching tests with ZnS and ferric iron showed similar concentrations of dissolved zinc with and without citrate. However, the actual leaching efficiency is yet to be evaluated.
Biosynthesis of Copper Nanoparticles Using Aqueous Extracts of Aloe vera and Geranium and Bioleaching Solutions
Authors: Pawlowska Agnieszka , Sadowski Zygmunt
Published: August 2017

Present work deals with synthesis of copper nanoparticles at the room temperature, using two aqueous extracts prepared from green and dry leaves of Aloe vera and Geranium (Pelargonium graveolens). Finely cut leaves were placed in the flask with the distilled water. The mixture was boiled for 15 min at the temperature of 60°C. After boiling, the mixture was centrifuged and pure extract was used for copper nanoparticles synthesis. The source of copper ions was leaching solution obtained from the bioleaching of copper shale (Kupferschiefier) using chemolithotrophic bacteria such as Acidithiobacillusfrerooxidans. The bioleaching procedure was performed in the column reactor.
Biooxidation of a High-Grade Arsenopyritic Gold Ore Using a Mixed Culture of Moderate Thermophilic Microorganisms
Authors: Abdolahi Hoda , Ahmadi Ali , Zilouei Hamid , Khezri Maryam
Published: August 2017

This study investigated the biooxidation of a high-grade refractory gold ore from the Zarshouran mine (West Azarbaijan, Iran) in shake flasks and a stirred tank bioreactor (STBR) using a mixed culture of moderately thermophilic microorganisms. The influence of four critical parameters including, pH, biooxidation time, nutrient medium type and pulp density on the iron and arsenic extraction as well as gold cyanidation were evaluated in a full factorial design in shake flasks at 45 °C. Maximum iron extraction was obtained in M9K medium, pulp density of 5% (w/v), 15 days of biooxidation time and the pH of 1.6. Biooxidation in the STBR was carried out at the pulp densities of 10% and 20% (w/v), the pH of 1.7 in the M9K medium, in which dissolved oxygen, pH, redox potential, iron and arsenic concentrations were measured during the process. It was found that 61% decrement of sulphur content in the STBR led to recover 80% of gold, which was 43% higher than that in the conventional cyanidation process. It can be concluded that the oxidation of refractory arsenopyrite gold ore can achieved using a moderately thermophilic biooxidation culture.
Preliminary Study on In Situ Realtime Quantitation of Target Bacteria on the Principle of Flow Cytometry
Authors: Murakami Gen , Sugai Yuichi , Sasaki Kyuro
Published: August 2017

In-situ realtime method that can monitor the target bacteria should be used to determine the real situation of the bacteria in deep parts of heaps in heap bioleaching plants. This study suggest to apply flow cytometry technology to in-situ realtime monitoring of target bacteria. Flow cytometry is a method that can rapidly quantify the bacterial cells in bacterial suspension based on the detection of lights that are emitted from bacterial cells. In this study, we estimated the possibility of the application of flow cytometry to the selective detection of target bacteria. The bacterial culture solution that had been diluted by water including other bacteria was provided for fluorescence spectral analysis and scattered light analysis that were functions of flow cytometry. Our target bacteria could be selectively detected by those analyses in this study, therefore, it was shown that the flow cytometry could be useful for detecting target bacteria selectively. Because the measurement principle of flow cytometry is quite simple, it can be expected to be installed into deep heaps through the monitoring wells and determine the dominance of target bacteria in-situ and realtime in the future.
The Impact of Heap Self-Heating on Microbial Activity during the Bioleaching of Low-Grade Copper Sulfide Ores
Authors: Shiers Denis W. , Collinson David M. , Watling Helen R.
Published: August 2017

In this study, a dynamically-controlled column was used to evaluate two ores known to cause heap overheating. This enabled the simulation of heap self-heating under controlled conditions. The lixiviant was inoculated with a consortia of mesophilic and moderately thermophilic microorgaisms, and the impact of rapid temperature increases on biological activity and cell numbers was evaluated. During the leaching of ore sample A, the temperature lagged for 29 days before increasing rapidly from 26 to 88 °C. Cell numbers and solution potential increased concomitantly, before both were reduced as the temperature increased past maximum microbial tolerances. Cell numbers began increasing again within 10 days of reaching temperatures that would facilitate mesophilic growth being restored. During the leaching of ore B, the temperature lagged for 4 days before exhibiting a rapid increase in temperature, increasing from 30 to 76 °C over a six-day period. Cell numbers were reduced with the sudden temperature increase, and did not recover over the remainder of the experiment.