bluuebunny/crossref_metadata_2025 huggingface dataset:
Disentangling the Frames, the State of Research on the Alphavirus 6K and TF Proteins
Authors: Ramsey Jolene , Mukhopadhyay Suchetana
Published: August 2017

For 30 years it was thought the alphavirus 6K gene encoded a single 6 kDa protein. However, through a bioinformatics search 10 years ago, it was discovered that there is a frameshifting event and two proteins, 6K and transframe (TF), are translated from the 6K gene. Thus, many functions attributed to the 6K protein needed reevaluation to determine if they properly belong to 6K, TF, or both proteins. In this mini-review, we reevaluate the past research on 6K and put those results in context where there are two proteins, 6K and TF, instead of one. Additionally, we discuss the most cogent outstanding questions for 6K and TF research, including their collective importance in alphavirus budding and their potential importance in disease based on the latest virulence data.
Targeting Persistent Human Papillomavirus Infection
Authors: Shanmugasundaram Srinidhi , You Jianxin
Published: August 2017

While the majority of Human papillomavirus (HPV) infections are transient and cleared within a couple of years following exposure, 10–20% of infections persist latently, leading to disease progression and, ultimately, various forms of invasive cancer. Despite the clinical efficiency of recently developed multivalent prophylactic HPV vaccines, these preventive measures are not effective against pre-existing infection. Additionally, considering that the burden associated with HPV is greatest in regions with limited access to preventative vaccination, the development of effective therapies targeting persistent infection remains imperative. This review discusses not only the mechanisms underlying persistent HPV infection, but also the promise of immunomodulatory therapeutic vaccines and small-molecular inhibitors, which aim to augment the host immune response against the viral infection as well as obstruct critical viral–host interactions.
Estimation of Water Demand in Water Distribution Systems Using Particle Swarm Optimization
Authors: Letting Lawrence , Hamam Yskandar , Abu-Mahfouz Adnan
Published: August 2017

Demand estimation in a water distribution network provides crucial data for monitoring and controlling systems. Because of budgetary and physical constraints, there is a need to estimate water demand from a limited number of sensor measurements. The demand estimation problem is underdetermined because of the limited sensor data and the implicit relationships between nodal demands and pressure heads. A simulation optimization technique using the water distribution network hydraulic model and an evolutionary algorithm is a potential solution to the demand estimation problem. This paper presents a detailed process simulation model for water demand estimation using the particle swarm optimization (PSO) algorithm. Nodal water demands and pipe flows are estimated when the number of estimated parameters is more than the number of measured values. The water demand at each node is determined by using the PSO algorithm to identify a corresponding demand multiplier. The demand multipliers are encoded with varying step sizes and the optimization algorithm particles are also discretized in order to improve the computation time. The sensitivity of the estimated water demand to uncertainty in demand multiplier discrete values and uncertainty in measured parameters is investigated. The sensor placement locations are selected using an analysis of the sensitivity of measured nodal heads and pipe flows to the change in the water demand. The results show that nodal demands and pipe flows can be accurately determined from a limited number of sensors.
Distributed Hydrological Modeling: Determination of Theoretical Hydraulic Potential & Streamflow Simulation of Extreme Hydrometeorological Events
Authors: Ibarra-Zavaleta Sara , Landgrave Rosario , Romero-López Rabindranarth , Poulin Annie , Arango-Miranda Raúl
Published: August 2017

The progressive change in climatic conditions worldwide has increased frequency and severity of extreme hydrometeorological events (EHEs). México is an example that has been affected by the occurrence of EHE leading to economic, social, and environmental losses. The objective of this research was to apply a Canadian distributed hydrological model (DHM) to tropical conditions and to evaluate its capacity to simulate flows in a basin in the central Gulf of Mexico. In addition, the DHM (once calibrated and validated) was used to calculate the theoretical hydraulic power (THP) and the performance to predict streamflow before the presence of an EHE. The results of the DHM show that the goodness of fit indicators between the observed and simulated flows in the calibration process Nash-Sutcliffe efficiency (NSE) = 0.83, ratio of the root mean square error to the standard deviation of measured data (RSR) = 0.41, and percent bias (PBIAS) = −4.3) and validation (NSE = 0.775, RSR = 0.4735, and PBIAS = 2.45) are satisfactory. The DHM showed its applicability: determination of THP showed that the mean flows are in synchrony with the order of the river reaches and streamflow simulation of 13 EHEs (NSE = 0.78 ± 0.13, RSR = 0.46 ± 0.14 and PBIAS = −0.48 ± 7.5) confirmed a reliable efficiency. This work can serve as a tool for identifying vulnerabilities before floods and for the rational and sustainable management of water resources.
Wet Spells and Associated Moisture Sources Anomalies across Danube River Basin
Authors: Ciric Danica , Nieto Raquel , Ramos Alexandre , Drumond Anita , Gimeno Luis
Published: August 2017

The Danube River Basin is the second longest catchment basin in Europe and exhibits intense climatological diversity. In recent decades, the frequency and intensity of daily precipitation extremes have suffered from an increment in many parts of the world, including Central and Eastern Europe. Wet spells are defined by the number of consecutive rainy days with different thresholds. The identification of wet spells and their trends in the rainfall time is very important for many sectors, such as agriculture, ecology, hydrology and water resources. Wet spells can lead to extreme events and cause floods and other disasters. In this study, we will attempt to characterise global precipitation in the context of wet spells and associated precipitation depth of wet spells in the Danube River Basin area using daily precipitation data, as well as analysing different approaches to identifying wet spells. The ten most intense wet spells were detected, and the most intense, which occurred on 23 September 1996, was studied in depth in terms of precipitation and associated anomalies, the synoptic situation and the anomalous transport of moisture using a Lagrangian approach. The existence of a marked west-east dipole in the field of sea level pressure between the Atlantic Ocean and the eastern Mediterranean leads to the anomalous moisture transport from the Northern Atlantic Ocean to the Mediterranean Sea, where a higher available amount of moisture existed, and subsequently penetrated within the low positioned over the Danube River Basin. In addition, an Atmospheric River was also responsible for the wet conditions in the Danube River Basin. The combination of all these factors was responsible for the extreme precipitation linked with the wet spell.
Recent Sedimentation Rates of Shallow Lakes in the Middle and Lower Reaches of the Yangtze River: Patterns, Controlling Factors and Implications for Lake Management
Authors: Xu Min , Dong Xuhui , Yang Xiangdong , Chen Xu , Zhang Qinghui , Liu Qian , Wang Rong , Yao Min , Davidson Thomas , Jeppesen Erik
Published: August 2017

Significantly increased sedimentation rates (SRs) in lakes worldwide in recent decades due to higher inputs of silt and eutrophication have led to significant environmental problems such as lake size diminishment and degraded water quality. Many lakes in the middle and lower reaches of the Yangtze River basin (MLYB) have followed this pattern. For effective lake management, it is essential to understand the pattern and drivers of SRs in these lakes. Fourteen typical lakes in the MLYB were chosen to examine the spatiotemporal patterns of SRs and identify the drivers over different time periods. Since 1900, SRs increased from <0.2 to 0.3–0.6 g·cm−2·year−1, particularly notable during 1930–1990. Combined with climatic factors, SR correlated negatively with lake (catchment) size and abundance of aquatic vegetation, whereas other lake features including nutrient status did not contribute significantly to the variation in SRs, due to the fast decomposition processes of organic matter in shallow lakes. Detrimental land use practices especially reclamation for croplands and rapid urbanization was revealed to elevate SRs pronouncedly. We propose various management strategies aiming to maintain SR reference condition at ~0.16 ± 0.08 g·cm−2·year−1, which is analogous to the SR value between 1850 and 1900.
Measuring Recovery to Build up Metrics of Flood Resilience Based on Pollutant Discharge Data: A Case Study in East China
Authors: Song Jinglu , Huang Bo , Li Rongrong
Published: August 2017

Building “disaster-resilient” rather than “disaster-resistant” cities/communities requires the development of response capabilities to natural disasters and subsequent recovery. This study devises a new method to measure resilience via recovery capability to validate indicators from social, economic, infrastructural, and environmental domains. The pollutant discharge data (waste-water and waste-gas discharge/emission data) of local power plants, sewage treatment plants and main factories were used to monitor recovery process of both people’s living and local industrial production as the waste water/gas is released irregularly during the short disaster-hit period. A time series analysis of such data was employed to detect the disturbance on these infrastructures from disasters and to assess community recovery capability. A recent record-breaking flash flood in Changzhou, a city in eastern-central China, was selected as a case study. We used ordinal logistic regression to identify leading proxies of flood resilience. A combination of six variables related to socioeconomic factors, infrastructure development and the environment, stood out and explained 61.4% of the variance in measured recovery capability. These findings substantiate the possibility of using recovery measurement based on pollutant discharge to validate resilience metrics, and contribute more solid evidences for policy-makers and urban planners to make corresponding measures for resilience enhancement.
Simulation and Regulation of Market Operation in Hydro-Dominated Environment: The Yunnan Case
Authors: Chen Fu , Liu Benxi , Cheng Chuntian , Mirchi Ali
Published: August 2017

This paper presents an integrated method to obtain optimal market operation and regulation with the objective of reducing the market price and increasing the electricity consumption in hydro-dominated electricity markets, in which giant cascaded hydropower facilities along different rivers are main power suppliers. To this end, a comprehensive indicator composed of market prices and electricity consumption is proposed to evaluate the situation of hydro-dominated market operation. Moreover, an iterative algorithm is proposed to investigate the strategic behaviors of power suppliers and to simulate the operation of the market. Furthermore, an integrated solution methodology based on a multi-core parallel tabu genetic algorithm (MPTGA) is proposed to provide the optimal assignment of bilateral contracts, considering the market simulation, in order to achieve the optimal market regulation. The results from the case study, with real data based on Yunnan’s electricity market, demonstrate that the proposed indicator and method are effective and efficient to simulate and regulate the market operation, and the effects of MPTGA are discussed last.
Fourteen polymorphic microsatellite markers for a widespread limestone endemic, Carex eburnea (Cyperaceae: Carex sect. Albae)
Authors: Gillespie Emily L. , Pauley Annabella G. , Haffner Megan L. , Hay Nikolai M. , Estep Matt C. , Murrell Zack E.
Published: August 2017

Premise of the study:

Microsatellite primers were developed for a widespread limestone endemic sedge, Carex eburnea, to facilitate investigation of the genetic diversity and phylogeography of this taxon and its closest relative, C. mckittrickensis.

Methods and Results:

Forty‐eight primer pairs were designed from Illumina sequence data and screened for suitability. Fourteen of these primer pairs were polymorphic and generated one to seven alleles per locus. Cross‐species amplifications were conducted for all four members of Carex sect. Albae.

Conclusions:

These primer pairs can be used to assess the genetic diversity and population structure in future studies of C. eburnea and C. mckittrickensis, and likely in other members of Carex sect. Albae.
Kepler Data on KIC 7341653: A Nearby M Dwarf with Monster Flares and a Phase-coherent Variability
Authors: Makarov Valeri V. , Goldin Alexey
Published: August 2017

KIC 7341653 is one of several late-type M dwarfs observed by the main mission of Kepler with peculiar infrared colors placing them in the domain of suspected young stellar objects (YSO). It is likely associated with a powerful X-ray emitter with X-ray flares. Kepler light curves reveal two distinct types of activity: frequent flares lasting from less than 30 minutes to a few hours, and a periodic variability with a period of 0.5463441(7) days. The largest detected flare increased the flux in the Kepler passband by a factor of 2.8 and released an estimated 4 × 1034 erg of energy in the Kepler band. Segmented periodogram analysis reveals that the amplitude of the periodic variation was subject to secular changes, dropping from peak values around 20 ppt to below 5 ppt toward the end of the mission, while the phase varied periodically with an amplitude of 0.15 rad and period 362(3) days. Two possible interpretations of the phase periodicity are discussed: a migrating long-lived photospheric spot, and a Doppler frequency shift generated by a solar-mass faint companion, such as a white dwarf.
RADYN Simulations of Non-thermal and Thermal Models of Ellerman Bombs
Authors: Hong Jie , Carlsson Mats , Ding M. D.
Published: August 2017

Ellerman bombs (EBs) are brightenings in the Hα line wings that are believed to be caused by magnetic reconnection in the lower atmosphere. To study the response and evolution of the chromospheric line profiles, we perform radiative hydrodynamic simulations of EBs using both non-thermal and thermal models. Overall, these models can generate line profiles that are similar to observations. However, in non-thermal models we find dimming in the Hα line wings and continuum when the heating begins, while for the thermal models dimming occurs only in the Hα line core, and with a longer lifetime. This difference in line profiles can be used to determine whether an EB is dominated by non-thermal heating or thermal heating. In our simulations, if a higher heating rate is applied, then the Hα line will be unrealistically strong and there are still no clear UV burst signatures.
The Evolution of the Phase Lags Associated with the Type-C Quasi-periodic Oscillation in GX 339–4 during the 2006/2007 Outburst
Authors: Zhang Liang , Wang Yanan , Méndez Mariano , Chen Li , Qu Jinlu , Altamirano Diego , Belloni Tomaso
Published: August 2017

We present the evolution of the phase lags associated with the type-C QPO in GX 339–4 during the rising phase of the 2006/2007 outburst. We find that the phase lags at the QPO frequency are always positive (hard) and show very different behavior between QPOs with frequencies below and above ∼1.7 Hz: when the QPO frequency is below ∼1.7 Hz, the phase lags increase both with QPO frequency and energy, while when the QPO frequency is above ∼1.7 Hz, the phase lags remain more or less constant. When the QPO frequency is higher than ∼1.7 Hz, a broad feature is always present in the lag–energy spectra at around 6.5 keV, suggesting that the reflection component may have a significant contribution to the phase lags. Below ∼1.7 Hz, the QPO rms first decreases with energy and then turns to almost flat, while above ∼1.7 Hz, the QPO rms increases with energy. During the transition from the low-hard state to the hard-intermediate state, the second harmonic and subharmonic of this QPO appear in the power density spectra. The second-harmonic and subharmonic phase lags show very similar evolutions for their centroid frequencies. However, the energy dependence of the second-harmonic and subharmonic phase lags are quite different. Our results suggest that, at different phases of the outburst, different mechanisms may be responsible for the phase lags of the QPO. We briefly discuss the possible scenarios for producing the lags.
Anchoring Polar Magnetic Field in a Stationary Thick Accretion Disk
Authors: Samadi Maryam , Abbassi Shahram
Published: August 2017

We investigate the properties of a hot accretion flow bathed in a poloidal magnetic field. We consider an axisymmetric viscous-resistive flow in the steady-state configuration. We assume that the dominant mechanism of energy dissipation is due to turbulence viscosity and magnetic diffusivity. A certain fraction of that energy can be advected toward the central compact object. We employ the self-similar method in the radial direction to find a system of ODEs with just one varible, θ in the spherical coordinates. For the existence and maintenance of a purely poloidal magnetic field in a rotating thick disk, we find that the necessary condition is a constant value of angular velocity along a magnetic field line. We obtain an analytical solution for the poloidal magnetic flux. We explore possible changes in the vertical structure of the disk under the influences of symmetric and asymmetric magnetic fields. Our results reveal that a polar magnetic field with even symmetry about the equatorial plane makes the disk vertically thin. Moreover, the accretion rate decreases when we consider a strong magnetic field. Finally, we notice that hot magnetized accretion flows can be fully advected even in a slim shape.
Discovery of the genus Nipponodipogon Ishikawa in the Oriental region, with description of two new species from China (Hymenoptera, Pompilidae)
Authors: Loktionov Valery M. , Lelej Arkady S. , Xu Zai-fu
Published: August 2017

The genusNipponodipogonIshikawa, 1965 is newly recorded from China (Guangdong, Hainan, and Yunnan) and the Oriental Region. Two new species,N. orientalisLoktionov, Lelej & Xu,sp. n.(Guangdong, Hainan, Yunnan) andN. shimizuiLoktionov, Lelej & Xu,sp. n.(Guangdong, Yunnan), are described and illustrated. The updated key to the species based on Shimizu et al. (2015) is given.
Iglesia, en Assy
Authors: Novarina Maurice
Published: August 2017

Esta iglesia, de aspecto recio y rústico, construida con materiales nobles y tradicionales —madera de abeto y piedra del país—, consigue darnos a entender, a primera vista, el propósito de su proyectista, acusando el carácter de construcción religiosa de montaña, sobre el fondo imponente de los altos picos nevados o cubiertos de espesa arboleda. Está situada en Assy —alta Saboya—, a 1.200 m de altura, y en sus cercanías existen varios sanatorios antituberculosos.
Iglesia, en Hinderburg
Authors: Bohn Dominikus
Published: August 2017

La iglesia de San José, emplazada en una amplia avenida de edificación alta, está concebida como una unidad arquitectónica concentrada, de gran volumen y armónica proporción de masas. Dos capillas, ciegas a la fachada principal y de 20 m de altura, se adelantan frente a la nave y rodean el antepatio, que está decorado con motivos primitivos del cristianismo.
Estructura prefabricada de una nave industrial
Authors: Swetchine Jean , Lebret R.
Published: August 2017

En la zona norte de París, barriada de Aubervilliers, se ha construido un almacén industrial por cuenta de la Société Générale de Fonderie, de 110 X110 m en planta. La cubierta de esta construcción, de elementos prefabricados, está constituida por una serie de lucernarios formando diente de sierra. En este trabajo se describen los principios de cálculo estático, métodos constructivos y de fabricación y montaje de los elementos estructurales.
El “Schokbeton”, en la prefabricación
Authors: Glastra van Loon F. P.
Published: August 2017

El Schokbeton es un material de composición semejante a la del hormigón ordinario, diferenciándose de éste, esencialmente, por el proceso particular que se emplea en su fabricación.
Traviesas de hormigón armado
Authors: Editorial Equipo
Published: August 2017

La sustitución de las traviesas de madera por otras de hormigón, fue idea concebida desde los comienzos del hormigón armado, a fines del siglo pasado, y tan criticada y experimentada, que hoy puede decirse que la utilización de la traviesa de hormigón armado ha pasado, definitivamente, del estado experimental al de empleo ordinario en la explotación de las vías férreas.
Prefabricación en madera. El sistema H B
Authors: Editorial Equipo
Published: August 2017

Los elementos HB constituyen una nueva forma de empleo de la madera en la construcción de pabellones industriales. El elemento HB fundamental se compone de una sección "I", en la cual tanto el alma como las alas están formadas por secciones normales de madera, cuyas fuerzas internas se transmiten por un sistema combinado de encolado y clavado.
Vigas prefabricadas ligeras para cubiertas de grandes luces. Procedimientos Barredo - pretensado
Authors: Editorial Equipo
Published: August 2017

Entre las múltiples aplicaciones del hormigón pretensado, se encuentran, y quizá como una de las soluciones más destacadas, las de prefabricación. Es decir, aquellas construcciones en que el elemento resistente ha sido construido mediante la utilización de unas piezas de mayor o menor tamaño, fabricadas independientemente antes de la construcción, y que, posteriormente, han sido unidas solidariamente mediante la adición de las armaduras pretesas.
Grúas ligeras
Authors: Editorial Equipo
Published: August 2017

Tipos y modelos de las más recientes innovaciones alemanas en materia de maquinaria auxiliar para la elevación de materiales en obras de edificación y extensibles a la construcción en general.
Effect on Aluminium Metal Matrix Composite Reinforced with Nano Sized Silica Particles
Authors: Nallusamy S. , Logeshwaran J.
Published: August 2017

In recent times, it could be observed that metal matrix composites receive considerable importance on account of improved properties compared to unreinforced alloys which includes high specific strength, specific modulus, damping capacity and good wear resistance. Interest in composites containing low density and low cost reinforcements has been since growing. Among various discontinuous particulate, silica is one of the most inexpensive and low density reinforcement available in large quantities. Hence, composites with aluminium oxide as reinforcement after the in-situ reaction of aluminium and silica are likely to overcome the cost barrier for wide spread applications in automotive and small engine applications. It is therefore expected that the incorporation of aluminium oxide particles in aluminium alloy will improve the mechanical properties of base material that will see increased usage in aircraft application due to reduced weight. In this research an effect on aluminum matrix composite reinforced with nano sized silica particles with different weight percentage was carried out. From the results it was found that the composites with 4 to 6wt% particle volume fraction to be the best with good tensile strength, yield stress and percentage elongation.
Thermal Conductivity Enhancement by Adding Nanoparticles to Ionic Liquids
Authors: Minea Alina Adriana , Moldoveanu Madalina Georgiana , Dodun Oana
Published: August 2017

Ionanofluids are a very new class of nanofluids having ionic liquids as the base fluid. Thermophysical properties of base ionic liquids (ILs) and nanoparticle enhanced ionic liquids (NEILs) are part of studying a new class of fluids for heat transfer. NEILs are formed by dispersing different volume fractions of nanoparticles in a base ionic liquid. In this article, only the thermal conductivity enhancement was considered for comparison of the different ionanofluids. NEILs show enhanced thermal conductivity compared to the base ILs. Maximum thermal conductivity enhancement was observed by adding 1 % MWCNT to [C4mim][(CF3SO2)2N] ionic liquid. However, if 0.05% MWCNT are added to [(C6)3PC14)][NTf2] no enhancement in thermal conductivity was noticed.
Computational Methods for the Assessment of Nanofluids in Abrasive Processes
Authors: Karkalos Nikolaos E. , Markopoulos Angelos P.
Published: August 2017

Metal cutting processes such as machining or abrasive processes are related to the production of relatively large amounts of heat, as a result of the intense contact of workpiece and cutting tool. For that reason, it is often necessary to employ a cooling fluid in order to alleviate the intense and usually undesired heat-induced effects on the workpiece. Due to the cost and environmental concerns regarding cutting fluids, the heat absorbing efficiency and quantity of cutting fluids employed is always a concern. In the present work, the effect of cutting fluid type in the temperature profile of the workpiece during grinding is investigated and useful conclusions are drawn, concerning the efficiency of nanofluids as cutting fluids.
Optimization of Nickel Alloy Turning Considering the Tool in Different Wear Phases
Authors: Zębala Wojciech
Published: August 2017

Paper presents some turning process optimization investigations, concerning modeling of tool wear when turning a difficult-to-cut material like nickel based alloy. The workpiece was an aircraft engine part in the form of disc. The aim of the research was an optimization of the cutting data (feed rate) for the purpose to improve the cutting process (stabilization of the cutting force course along the tool path) and increase the material removal rate (efficiency of the machining). A “force material model”, based on the tool behavior in its different wear phases was established.
Effect of Cutting Feed and Chip Size Ratio on Cutting Force
Authors: Kundrák János , Makkai Tamás , Deszpoth István
Published: August 2017

In producing parts, besides increasing accuracy and maintaining/improving the cut surface quality, the main effort of the manufacturers is to improve the productivity/profit. In face milling this aim can be achieved first of all by increasing cutting speed and feed. The importance of feed impact analysis is justified by the general effort to prefabricate parts near net shape, if possible by one pass material removal. If the manufacturing is done by one pass, the surface rate (Aw, mm2/min) can be increased by the increase of feed. It fz feed is increased, the feed per tooth (keeping ap at constant value) ap/fz ratio is changed and as a consequence also the load on cutting edges and the character of chip deformation. The increase in the feed and the change in the chip cross section shape influence the cutting forces and the efficiency. In this paper, the changes in the cutting force components with different feed rates are demonstrated, while the value of the feed is increased 16-fold.
Design and Machining of the Femoral Component of Total Knee Implant
Authors: Markopoulos Angelos P. , Karkalos Nikolaos E. , Galanis Nikolaos I. , Manolakos Dimitrios E.
Published: August 2017

Manufacturing of medical implants constitutes always a challenge, regarding the constraints involved for these applications, e.g. need for suitable materials or appropriate dimensional tolerances. The aforementioned pose also challenges for the machining process itself, regarding the appropriate machining conditions and machine tool setup and so it is considered as a subject of interest. In the present work, the manufacturing process for knee implants, especially for the femoral component of this type of implants, is discussed, encompassing all the stages from design and planning of each step of the process up to actual machining of the implant component. Finally, the surface quality of the implant after finishing process is assessed for each of the three different finishing processes applied, in order to determine the suitable machining parameters required.
Study on Spindle Vibration and Surface Finish in Turning of Al 7075
Authors: Şahinoğlu Abidin , Karabulut Şener , Güllü Abdulkadir
Published: August 2017

In this study, the relationship between the spindle vibration and surface roughness was investigated and the effect of the cutting parameters on surface roughness and spindle vibration during the machining of Aluminum alloy 7075 (Al 7075) were determined. Experimental studies have been carried out on a CNC turning machine using coated cemented carbide cutting tools under dry cutting environment. L64 full factorial design of experiments was used to investigate the optimal machining parameters for spindle vibration and surface roughness. The influences of machining parameters on vibration and surface roughness were evaluated by using analysis of variance (ANOVA) and main effect plots. The results revealed that the feed rate was the most effective cutting parameters on spindle vibration and surface roughness. The machine tool vibration amplitude and surface roughness values were significantly increased with increasing cutting feed. The depth of cut and cutting speed have the least effect on the spindle vibration and indicated an insignificant effect on surface roughness. Mathematical equations were developed to predict the vibration and surface roughness values using the regression analysis.
Experimental Investigation of Cutting Conditions from the View of Force Load at High Speed Milling
Authors: Řehoř Jan , Fulemová Jaroslava , Vagaská Alena , Gombár Miroslav , Monkova Katarina
Published: August 2017

The article deals with the experimental investigation of cutting conditions from the view of force load during machining high alloyed tool steel EŠ 419556 (standard by Škoda a.s. Pilsen, based on DIN 1.2326) at high speed milling. The aim of presented research is investigation of the most favourable contact and cutting conditions to minimize the power load of the cutting edge. Processing of measurement results within presented investigation was focused only on the components of cutting force FC (tangent) and FCN (normal) that adequately characterize the cutting process. The experiments were also carried out at cutting depth (ap) changing during high speed milling. The obtained results are presented in the paper by means of graphs that clearly show the behaviour of cutting force components at given conditions.
Choosing Profile Shift Coefficients for Spur Gears
Authors: Tomori Zoltán , Szente József , Vadászné Bognár Gabriella
Published: August 2017

Methods used earlier for choosing profile shift coefficients were based on presumed advantages without physical proof justifying them. In this paper a new method is proposed which guaranties a positive influence on gear failures and on the operational conditions of gear pairs.
New Challenges for Quality Assurance of Manufacturing Processes in Industry 4.0
Authors: Illés Béla , Tamás Péter , Dobos Péter , Skapinyecz Róbert
Published: August 2017

Nowadays the flexibility and specific cost of manufacturing have a relevant role in the competitiveness of the companies. In our opinion the most important objective of Industry 4.0 is the realization of intermittent manufacturing at mass production’s productivity and specific cost. This aim can be only reached by creating more complex manufacturing systems. The increase in manufacturing complexity results in new challenges in the quality assurance of manufacturing processes. We can collect new types of data that enable the improvement of product and process service quality. This paper introduces the essence of Industry 4.0, as well as the new challenges for the quality assurance of manufacturing processes. Possible research directions for overcoming challenges are also presented.
A Method for Determination of the Minimal Thickness of the Cutting Layer during Precision Machining Performed with the Indexable Cutting Tools
Authors: Krajewska-Śpiewak Joanna , Gawlik Józef
Published: August 2017

Under the influence of the pressure caused by the application of the cutting edge on the surface of the workpiece elastic waves are generated. Waves propagate in the material in every possible direction and can be identify by specialized measuring equipment. Acoustic emission phenomenon was used to determine the beginning of decohesion process. The article presents a new method for determination of the decohesion process during peripheral milling performed with the indexable cutting tools on samples made out of titanium based alloy and nickel based alloy.
Supply Chain Design of Manufacturing Processes with Blending Technologies
Authors: Bányainé Tóth Ágota , Illés Béla , Schenk Fabian
Published: August 2017

Blending technologies play an important role in manufacturing. The design and operation of manufacturing processes using blending technologies represent a special range of manufacturing related logistics because the integrated approach of technological and logistic parameters is very significant. This research proposes an integrated model of supply of manufacturing processes using blending technologies. After a careful literature review, this paper introduces a mathematical model to formulate the problem of supply chain design for blending technologies. The integrated model includes the optimal purchasing strategy depending on the characteristics of components to be mixed in the desired proportion and the costs of supply. The integrated model will be described as a linear programming problem. Numerical results with different datasets demonstrate how the proposed model takes technological and logistic aspects into consideration.
Examining the Integration Possibilities for Lean Tools and Simulation Modeling
Authors: Tamás Péter , Illés Béla
Published: August 2017

Nowadays the application mode of the tool and rule systems of the lean philosophy plays a relevant role in the competitiveness of companies. Basically, the advantage is realized by reduction of logistics wastes. In our opinion integration of the more important lean tools (VSM, SMED, Kanban) with simulation modeling may be necessary in many cases in order to increase efficiency in manufacturing/production processes. The paper presents these possibilities. In addition, it outlines research directions in connection with the examined areas.
Fabrication and Application of Polyethylenimine/Ca-Alginate Blended Hydrogel Fibers as High-Capacity Adsorbents for Recovery of Gold from Acidic Solutions
Authors: Bediako John Kwame , Song Myung Hee , Yun Yeoung Sang
Published: August 2017

High-capacity polyethylenimine (PEI)/Ca-alginate blended hydrogel fibers were fabricated via three steps, viz. electrostatic blending of PEI and alginate, ionotropic gelation of alginate and CaCl2, and fixing of PEI into the Ca-alginate matrix, using glutaraldehyde (GA) as a crosslinker. Two crosslinking approaches resulted in different stabilities and gold uptake capacities of the prepared sorbents. Post-crosslinking approach was more efficient than pre-crosslinking likely owing to the better crosslinking efficiency, leading to better stability and sorption capacity. Furthermore, X-ray diffraction (XRD) study revealed the reduction of Au (III) to metallic gold, Au (0) in the crosslinked fibers. The Au (0) predominancy was confirmed with a metal desorption study. The present study thus demonstrates the possibility of recovering metallic gold from aqueous solutions by direct adsorption-coupled-reduction approach using GA-crosslinked PEI/Ca-alginate fibers.
Bioleaching of Supergene Porphyry Copper Ores from Sungai Mak Gorontalo of Indonesia by an Iron- and Sulfur-Oxidizing Mixotrophic Bacterium
Authors: Chaerun Siti Khodijah , Putri Frideni Yushandiana , Mubarok Mohammad Zaki , Minwal Wahyudin Prawira , Ichlas Zela Tanlega
Published: August 2017

Environmentally friendly mining technologies have to be developed extensively to avoid the impact of mining activities with respect to environmental concern. One example of such technology is bioleaching which has been developed worldwide and is regarded as an appropriate technology for the extraction of metals from polymetallic ores such as supergene porphyry copper ores, mainly consisting of secondary copper sulfides, including chalcocite (Cu2S), covellite (CuS), or oxide minerals, i.e., cuprite (Cu2O) and tenorite (CuO). The extraction process for this complex ore generally requires high temperature, high pressure and/or high acid concentration. For the economic extraction of valuable copper from such ores, the bioleaching of supergene porphyry copper ore from Sungai Max in Southeast Sulawesi of Indonesia was investigated in shake-flask experiments at room temperature (28 °C) for 14 days using an iron- and sulfur-oxidizing bacterium (Alicyclobacillus sp.) indigenous to an Indonesian mine site. The main mineralogical composition of gangue minerals contained in this ore sample included quartz, muscovite, kaolinite and alunite. The relatively high copper extraction efficiencies were obtained over a 14-day period of the bioleaching experiments as a function of pH, pulp density and NaCl concentration. Therefore, the findings of this study provide the first information of bioleaching process of supergene porphyry copper ores in Indonesia that may highly be useful for developing an economical and environmentally friendly extraction process of such complex ores.
Biodesulfurization of a Coarse-Grained High Sulfur Coal in a Full-Scale Packed-Bed Bioreactor
Authors: Milan Ahmad Doodkanlou , Ahmadi Ali , Hosseini Seyed Mohammad Raouf
Published: August 2017

Biodesulfurization of a high-sulfur and medium-ash coal product was carried out in a 5-m tall packed bed bioreactor using a mixed culture of iron- and sulfur- oxidizing microorganisms. The feed coal (4 tones) was obtained from a heavy media cyclone product from Takht-Zeitoon coal mine (Tabas, Iran) with a density of -1.4 g/cm3 and a grain size of 0.5-25 mm, having the ash and sulfur contents of 14.92% and 2.46%, respectively. The pilot scale process was performed in a semi-continuous mode with a solution injection rate of 2.5-4.5 lit/min/m2, aeration rate of 4-12 m3/h/m2 and solution pH of 1.7-2, over a period of 190 days. Iron and sulfate ions were controlled during the process in two 1500-L stirred tank reactors by goethite and gypsum precipitation processes, respectively. The column biodesphurization in a period of 170 days was followed by a washing step with HCl to remove sulfate precipitates. Results showed that the total sulfur and ash contents reached to 1.69% and 11.04%, respectively, which were corresponded to 31% sulfur removal and 26% ash removal. It was indicated that biodesulfurization has a good industrial potential to treat coarse-grained high sulfur coals.
Microbial Survey on Industrial Bioleaching Heap by High-Throughput 16S Sequencing and Metagenomics Analysis
Authors: Acosta Mauricio , Galleguillos Pedro A. , Guajardo Mariela , Demergasso Cecilia
Published: August 2017

Bioleaching processes are usually open systems where introduced and native microorganisms survive to changes in pH, temperature, salt and metal concentration, among others. Spatial and temporal description of the microbial community could be relevant for better comprehension of copper extraction process and help in the development of operative procedures to improve the metal extraction. We performed metagenomics and high-throughput sequencing of 16S rRNA genes analyses on samples from Escondida mine bioleaching heap and laboratory columns tests. Archaeal community structure in samples was assessed using three pairs of Archaea-specific primers, and results were highly depending on the primers pairs used. Similarly, three pairs of Bacteria-specific primers were used to assess the bacterial community. Moreover, according to the metagenomics analysis, At. thiooxidans, F. acidarmanus, Leptospirillum spp., Acidiphilium sp. JA12-A1, Acidiphilium spp., At. ferrivorans, and Leptospirillum ferriphilum were the most representative microorganisms. The repercussion of the different methodologies and outputs in the characterization of the bioleaching microbial community is discussed. A better understanding of the microbial community in bioleaching processes could improve the analysis regarding environmental changes in the heap process, its metallurgical performance and, can be used to assist in the decision-making process.
Comparison of Reductive and Oxidative Bioleaching of Jarosite for Valuable Metals Recovery
Authors: Mäkinen Jarno , Salo Marja , Hassinen Hanna , Kinnunen Päivi
Published: August 2017

Jarosite is a typical stream of zinc refineries, with high production rates and possible release of metal-contaminated seepage waters during long-term storage in respective disposal sites. Jarosite contains remarkable concentrations of valuable metals, like several weight percentages of zinc and lead, in addition to lower concentrations of copper, silver, germanium, gallium and indium. In this study, jarosite was treated with reductive and oxidative bioleaching for valuable metals recovery. The reductive bioleaching was seen to enhance iron liberation, by transforming the dissolved Fe(III) to Fe(II), while in the oxidative bioleaching iron liberation was lower. Zinc, copper, indium, gallium and germanium dissolution rates were rather identical with both methods. In reactor experiments, the zinc and copper yields were higher than in flask experiments resulting at best in the leaching yield of 35% and 38% for zinc and copper, respectively. Indium and gallium yields were between 5-8%, but approximately 40% of germanium was leached.
Influence of CO2 Supplementation on the Bioleaching of a Copper Concentrate from Kupferschiefer Ore
Authors: Guézennec Anne Gwénaëlle , Joulian Catherine , Jacob Jérôme , Bodenan Françoise , d'Hugues Patrick , Hedrich Sabrina
Published: August 2017

In bioleaching processes using autotrophic bacteria, CO2 is the carbon source for the growth of the microorganisms and its availability is dependent on gas mass transfer. The objective of this study was to investigate the demand in CO2 in complex copper concentrate bioleaching operations and to optimize CO2 supply. Batch tests in 2L-stirred reactors at 10%w/v solid load were performed to study the need for CO2-supplementation and to determine the adequate CO2 partial pressure in the gas inlet. The results show that Fe oxidation (and thus microbial activity) is delayed when air is injected without CO2-supplementation. CO2-supplementation improves leaching kinetics since Cu dissolution rate increases from 84 mg/L/h with air solely to 120 mg/L/h when CO2 is added to air. The study proposes also a methodology to determine G/L transfer components and to asses CO2 limitations in the system. It shows that the microorganisms are not only sensitive to the transfer rate of CO2 from the gas to the liquid phase, but also to the availability of CO2 in solution.
Unravelling the Complexity of Heap Bioleaching
Authors: Petersen Jochen
Published: August 2017

Heap and dump leaching of sulphide minerals have become well-established techniques for the processing of low grade ores, especially of copper, over the past 30 years. The oxidative dissolution of sulphides in heaps can be significantly enhanced by microbial colonies, but the complexities of the heap leach process overall often counteract the potential advantages, or prevent microbial colonisation and bioleaching in the first place.
This overview discusses the multiple layers of complexities that govern percolation leaching processes, such as the interactions between mineral grains, particle pores and leach solution, microbial responses to solution chemistry typical of heaps, solution and solute transport in heterogeneous unsaturated ore beds, as well as heap aeration and microbial response to CO2 supply. It becomes clear that economically successful heap bioleaching hinges on careful engineering and operation of the heap process as a whole to create an environment in which microbial colonies can thrive and the value metal is released sufficiently rapidly into solution.
Copper Heap Bioleach Microbiology - Progress and Challenges
Authors: Roberto Frank F.
Published: August 2017

Molecular approaches to studying the microbiology of copper bioleach heaps have greatly increased our knowledge of the microbial diversity in these environments. Nevertheless, technical and operational challenges exist that prevent obtaining samples from commercial-scale heaps necessary to improve our understanding of the temporal changes that occur during heap maturation and the progression of copper leaching.
From Knowledge to Best Practices in Bioleaching
Authors: Demergasso Cecilia , Véliz Roberto , Galleguillos Pedro A. , Marín Sabrina , Acosta Mauricio , Zepeda Víctor J. , Bekios Juan , Zeballos Jaqueline
Published: August 2017

The huge industrial data recorded by several years in copper bioleaching operations represents an opportunity for the technology improvement. A systematic approach is being developed to get insights from the field data from an industrial process and to deliver the obtained knowledge with the aim to serve as the foundation for optimal industrial decision making even in presence of inherent process variations. The development of this Decision Support System (DSS) considers a Q-PCR array, a database for data logging and storage, the application of suitable statistical and computational tools for data analyses and knowledge acquiring and finally the creation of a system of knowledge translation to transform it into action (operational suggestions). The user can accurately retrieve data and design similar matches to the historic operation to get e.g. the expected metallurgical performance of a strip based on its mineralogical parameters. In addition, the user can get computed information and recommendations that should be analyzed. We will discuss the process followed to construct the base of knowledge of the DSS.
The Mechanism of In and Ge Occurrence in Sphalerite Crystal and the Influence on Properties: A DFT (Density Function Theory) Simulation
Authors: Tong Lin Lin , Yang Hong Ying , Xu Jia Ning , Xu Peng Cheng , Li Chao
Published: August 2017

In and Ge can be found in Sphalerite crystal which can influence bio-leaching properties of Sphalerite significantly. Occurrence states of In and Ge in Sphalerite crystal and their influence on Sphalerite was calculated by Castep package. The most stable occurrence states are In and Ge substitute for Zn atom in Sphalerite crystal. When In and Ge existed in Sphalerite crystal, the Density of states (DOS) of Sphalerite crystal moved to left, meaning a more reducibility structure. It can explain why In and Ge bearing Sphalerite is easier to bio-leach than the pure sphalerite.
Innovative Biohydrometallurgical Approaches in the EU Project FAME
Authors: Reichel Susan , Martin Mirko , Bryan Christopher G. , Vila Cristina , Fiúza António , Reimer Wolfgang
Published: August 2017

The FAME (Flexible and Mobile Economic Processing Technologies) project targets the development of flexible and economic processing technologies for small and low-grade European ore deposits with complex mineralogy, targeting greisen, skarn and pegmatite ores. Amongst the valuable elements to be recovered are W, Sn, Li and minor constituents like In, Ge, Ga, Nb or Ta. To improve the processing of by-product sulfides to recover critical elements like In or Ga and to develop innovative processing strategies for raw materials, biohydrometallurgical technologies are investigated. There are different approaches in FAME for the biohydrometallurgical recovery of valuable metals from low grade ores: 1) the extraction of Li from zinnwaldite and lepidolite, 2) the heap leaching of low grade sulfide ore unsuitable for conventional processing to recover Zn and In, and 3) the bioleaching of sulfide concentrates in a two-stage tank process for recovery of Zn and Cu. So far the most promising results were achieved for heap-leaching of low-grade Zn-In ores achieving 7.4 ppm In in the leaching solution and for Li extraction (28%) from zinnwaldite.