bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic field variations associated with umbral flashes and penumbral waves
Authors: Joshi Jayant , de la Cruz Rodríguez Jaime
Published: September 2018

Context. Umbral flashes (UF) and running penumbral waves (RPWs) in sunspot chromospheres leave a dramatic imprint in the intensity profile of the Ca II 8542 Å line. Recent studies have focussed on also explaining the observed polarization profiles, which show even more dramatic variations during the passage of these shock fronts. While most of these variations can be explained with an almost constant magnetic field as a function of time, several studies have reported changes in the inferred magnetic field strength during UF phases. These changes could be explained by opacity effects or by intrinsic changes in the magnetic field strength.

Aims. In this study we investigate the origin of these periodic variations of the magnetic field strength by analyzing a time-series of high-temporal-cadence observations acquired in the Ca II 8542 Å line with the CRISP instrument at the Swedish 1-m Solar Telescope. In particular, we analyze how the inferred geometrical height scale changes between quiescent and UF phases, and whether those changes are enough to explain the observed changes in the magnetic field, B.

Methods. We have performed non local thermodynamical equilibrium (non-LTE) data inversions with the NICOLE code of a time-series of very high spatio-temporal-resolution observations in the Ca II 8542 Å, Fe I 6301.5, and Fe I 6302.5 Å lines. We analyze in detail the variations of the different physical parameters of the model as a function of time.

Results. Our results indicate that the Ca II 8542 Å line in sunspots is greatly sensitive to magnetic fields at log τ500 = −5 (hereafter log τ = −5) during UFs and quiescence. However this optical depth value does not correspond to the same geometrical height during the two phases. Our results indicate that during UFs and RPWs the log τ = −5 is located at a higher geometrical height than during quiescence. Additionally, the inferred magnetic field values are higher in UFs (up to ∼270 G) and in RPWs (∼100 G).

Conclusions. Our results suggest that opacity changes caused by UFs and RPWs cannot explain the observed temporal variations in the magnetic field, as the line seems to form at higher geometrical heights where the field is expected to be lower.
Dissecting stellar chemical abundance space with t-SNE
Authors: Anders F. , Chiappini C. , Santiago B. X. , Matijevič G. , Queiroz A. B. , Steinmetz M. , Guiglion G.
Published: September 2018

In the era of large-scale Galactic astronomy and multi-object spectroscopic stellar surveys, the sample sizes and the number of available stellar chemical abundances have reached dimensions in which it has become difficult to process all the available information in an effective manner. In this paper we demonstrate the use of a dimensionality-reduction technique (t-distributed stochastic neighbour embedding; t-SNE) for analysing the stellar abundance-space distribution. While the non-parametric non-linear behaviour of this technique makes it difficult to estimate the significance of any abundance-space substructure found, we show that our results depend little on parameter choices and are robust to abundance errors. By reanalysing the high-resolution high-signal-to-noise solar-neighbourhood HARPS-GTO sample with t-SNE, we find clearer chemical separations of the high- and low-[α/Fe] disc sequences, hints for multiple populations in the high-[α/Fe] population, and indications that the chemical evolution of the high-[α/Fe] metal-rich stars is connected with the super-metal-rich stars. We also identify a number of chemically peculiar stars, among them a high-confidence s-process-enhanced abundance-ratio pair (HD 91345/HD 126681) with very similar ages and v

X
and v

Y
velocities, which we suggest have a common birth origin, possibly a dwarf galaxy. Our results demonstrate the potential of abundance-space t-SNE and similar methods for chemical-tagging studies with large spectroscopic surveys.
Seismic characterization of red giants going through the helium-core flash
Authors: Deheuvels S. , Belkacem K.
Published: September 2018

Context. First-ascent red giants in the approximate mass range 0.7 ≲ M/M⊙ ≲ 2 ignite helium in their degenerate core as a flash. Stellar evolution codes predict that the He flash consists of a series of consecutive subflashes. Observational evidence of the existence of the He flash and subflashes is lacking. The detection of mixed modes in red giants from space missions CoRoT and Kepler has opened new opportunities to search for such evidence.

Aims. During a subflash, the He-burning shell is convective, which splits the cavity of gravity modes in two. We here investigate how this additional cavity modifies the oscillation spectrum of the star. We also address the question of the detectability of the modes, to determine whether they could be used to seismically identify red giants passing through the He flash.

Methods. We calculate the asymptotic mode frequencies of stellar models going through a He subflash using the Jeffreys-Wentzel-Kramers-Brillouin (JWKB) approximation. To predict the detectability of the modes, we estimate their expected heights, taking into account the effects of radiative damping in the core. Our results are then compared to the oscillation spectra obtained by numerically calculating the mode frequencies during a He subflash.

Results. We show that during a He subflash, the detectable oscillation spectrum mainly consists of modes trapped in the acoustic cavity and in the outer g-mode cavity. The spectrum should thus at first sight resemble that of a core-helium-burning giant. However, we find a list of clear, detectable features that could enable us to identify red giants passing through a He subflash. In particular, during a He subflash, several modes that are trapped in the innermost g-mode cavity are expected to be detectable. We show that these modes could be identified by their frequencies or by their rotational splittings. Other features, such as the measured period spacing of gravity modes or the location of the H-burning shell within the g-mode cavity could also be used to identify stars going through a He subflash.

Conclusions. The features derived in this study can now be searched for in the large datasets provided by the CoRoT and Kepler missions.
Super star cluster feedback driving ionization, shocks and outflows in the halo of the nearby starburst ESO 338-IG04
Authors: Bik A. , Östlin G. , Menacho V. , Adamo A. , Hayes M. , Herenz E. C. , Melinder J.
Published: September 2018

Context. Stellar feedback strongly affects the interstellar medium (ISM) of galaxies. Stellar feedback in the first galaxies likely plays a major role in enabling the escape of LyC photons, which contribute to the re-ionization of the Universe. Nearby starburst galaxies serve as local analogues allowing for a spatially resolved assessment of the feedback processes in these galaxies.

Aims.We aim to characterize the feedback effects from the star clusters in the local high-redshift analogue ESO 338-IG04 on the ISM and compare the results with the properties of the most massive clusters.

Methods. We used high quality VLT/MUSE optical integral field data to derive the physical properties of the ISM such as ionization, density, shocks, and performed new fitting of the spectral energy distributions of the brightest clusters in ESO 338-IG04 from HST imaging.

Results.We find that ESO 338-IG04 has a large ionized halo which we detect to a distance of 9 kpc. We identify four Wolf-Rayet (WR) clusters based on the blue and red WR bump. We follow previously identified ionization cones and find that the ionization of the halo increases with distance. Analysis of the galaxy kinematics shows two complex outflows driven by the numerous young clusters in the galaxy. We find a ring of shocked emission traced by an enhanced [O I]/Hα ratio surrounding the starburst and at the end of the outflow. Finally we detect nitrogen enriched gas associated with the outflow, likely caused by the WR stars in the massive star clusters.

Conclusions. Photoionization dominates the central starburst and sets the ionization structure of the entire halo, resulting in a density bounded halo, facilitating the escape of LyC photons. Outside the central starburst, shocks triggered by an expanding super bubble become important. The shocks at the end of the outflow suggest interaction between the hot outflowing material and the more quiescent halo gas.
X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli
Authors: Perdelwitz V. , Czesla S. , Robrade J. , Pribulla T. , Schmitt J. H. M. M.
Published: September 2018

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components.

Aims.We extend the sample of low-mass binary systems with well-known X-ray properties.

Methods.We analyze data from a singularXMM-Newtonpointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling toolPHOEBEand data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation.

Results.We find clear evidence of orbital modulation in the UV light curve and show thatPHOEBEis fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based onPHOENIXmodels shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.
The forming and emission of high power electromagnetic pulses
Authors: Jakubiuk Kazimierz , Kowalak Daniel , Nowak Mikołaj
Published: September 2018

An impulse energy source, a power conditioning system and an electromagnetic field emitter are essential to generate an electromagnetic field pulse (EMFP) with a specific frequency bandwidth. Selected simulation results for a power conditioning system consisting of a fuse opening switch and a paraboloidal electromagnetic emitter have been presented in this article. The synthetic system examined in the simulation is powered by an impulse capacitor instead of a flux compression generator (FCG) used in practice. The obtained results confirm that pulse generation and emission of high-power EMFP is possible.
Magnetic field of a ribbon busbar of finite length
Authors: Kusiak Dariusz , Szczegielniak Tomasz , Piątek Zygmunt
Published: September 2018

Using the analytic method based on the Biot-Savart law for the electromagnetic field, the distribution of the magnetic field of a ribbon busbar of finite length has been determined. The Mathematica program was used to visualize the solutions obtained. This allowed quick field analysis after changes of geometrical or electrical parameters of systems under examination.
Immunity test of the lighting installation for electromagnetic surge disturbances
Authors: Typańska Dorota , Machczyński Wojciech
Published: September 2018

The paper presents the results of computer simulation of the operation of a lighting installation disturbed by a voltage surge of 1.2 / 50 μs. The components included in the model of the system were: voltage surge generator (accordance with the PN-EN 61000-4-5 Standard), coupling - decoupling system, over-current circuit breaker, iluminance level controller and incandescent lamp. The results of simulation tests with the results of tests carried out in an accredited electromagnetic compatibility laboratory were compared.
Analysis of efficiency of photovoltaic bifacial cells
Authors: Kurz Dariusz , Lewandowski Kamil , Szydłowska Martyna
Published: September 2018

The paper presents the characteristic features and parameters of photovoltaic bifacial cells such as BGE – Bifacial Gain Energy and BR – Bifacial Ratio. Simulation test results of power yields and efficiency from bifacial panels for different values of irradiation and BGE ratio were presented.
Measurements and calculations of capacitances of BJT and SJT made of silicon carbide
Authors: Szelągowska Joanna , Zarębski Janusz
Published: September 2018

In the paper the results of capacitance-voltage (C-V) characteristics measurements of the current controlled BJT and SJT transistors were presented, for which a programmable measuring system manufactured by Keithley was used. The results of measurements was compared with results of the calculations obtained by using the commonly used Gummel-Poon model. For comparison, the results of the measurements found in the literature and in the datasheets of the considered devices were presented as well. The temperature impact on the shape of the considered characteristics was also investigated.
Evaluation of accuracy of SiC-JFET macromodel
Authors: Bargieł Kamil , Bisewski Damian
Published: September 2018

In the paper, the results of experimental verification of the macromodel of UJN1208K JFET transistor made of silicon carbide fabricated by United Silicon Carbide, are presented. The macromodel form dedicated for PSPICE program is available on the manufacturer's website. The accuracy of the macromodel have been evaluated by comparison of selected calculated and measured static characteristics and C-V characteristics of the considered transistor. The influence of ambient temperature on the characteristics of the transistor has been evaluated, as well.
A fast switched reluctance motor controller based on FPGA
Authors: Rataj Daniel , Slawik Dennis , Wrobel Krzysztof , Tomczewski Krzysztof
Published: September 2018

The paper presents the concept and practical implementation of a switched reluctance motor control system in an FPGA programmable device. The developed control system was designed for testing high-speed motors in order to limit the delays of output signals in relation to the signals from the encoder. The controller enables the values of commutation angles and PWM voltage to be set along with current limit values, measures the values of voltages and currents, and sends the results to the computer to be archived.
Implementation of the lighting control algorithms in the KNX system
Authors: Sowa Sławomir , Gielniak Jarosław
Published: September 2018

There are many different ways of managing the lighting. The usage of appropriately selected controlling algorithms allows to increase the functionality, improve the comfort of using and introduces measurable benefits in the form of power consumption savings. In order to precisely apply the proper lighting control algorithms, it is important to know the distribution of light intensity in the room. This article is aimed at comparing different ways of lighting control and contains a control idea based on the KNX system, which is a popular building automation system. It is very useful for the implementation of lighting control criteria.
Comparison of edge detection algorithms for electric wire recognition
Authors: Kowalski Paweł , Czyżak Maciej , Smyk Robert
Published: September 2018

Edge detection is the preliminary step in image processing for object detection and recognition procedure. It allows to remove useless information and reduce amount of data before further analysis. The paper contains the comparison of edge detection algorithms optimized for detection of horizontal edges. For comparison purposes the algorithms were implemented in the developed application dedicated to detection of electric line wires. The optimized algorithms were benchmarked on a set of images of electric wires.
Triethylammonium hydrogen sulfate ionic liquid as a low-cost solvent: A short review of synthesis, analysis and applications
Authors: Zahari S. M. Shahrul Nizan Shikh , Azman Hazeeq , Karim Latifah
Published: September 2018

This review does not attempt to be comprehensive, but it briefly introduces triethylammonium hydrogen sulfate ionic liquid ([N2220][HSO4] IL), which has been regarded as a low-cost solvent. It provides guidance regarding the synthesis procedures of the IL and several routine assessments for gaining insight into the properties of the IL. The review also selects examples of applications wherein the IL has been applied. It is hoped that the review will stimulate more research utilising the [N2220][HSO4] IL across various disciplines of science and engineering.
A study on perceptions of preschool Children’s furniture design: Pictorial stimuli experiment
Authors: Tamthintha Pornchai , Palaprom Kusuma , Nawattanaprasert Kritchakhis
Published: September 2018

The preschool center there is a place for educational topreschool children before they begin compulsory education at primary school. The different of the preschool children’s furniture will affect the different perceptions of preferences and behaviors of children in the classroom. The furniture that relating the satisfaction of children. It will become the part of stimulus that attracts and motivates children and also an appropriate physical elements to encourage a learning environment. The research found that the different elements of design on the preschool children’s furniture affect the perceptions of children they prefer the follow: warm colors on children’s desk and chair while cool colors on bookshelves, and non-pattern, natural (animal) form and natural (wood) material on children’s desk, children’s chair and bookshelves.The study results can help designers in their selection of elements of design on the preschool children’s furniture, specially for classroom in the preschool center.
Development of sustainable procurement monitoring system performance based on Supply Chain Reference Operation (SCOR) and Analytical Hierarchy Process (AHP) on leather tanning industry
Authors: Waaly Arditya Nur , Ridwan Ari Yanuar , Akbar Mohammad Deni
Published: September 2018

the industrial sector in Indonesia is increasing from year to year, the increase of the industrial sector is due to the increase of export and domestic demand. Indonesia is also an option for industrial sector because Indonesia is a strategic area besides the cost in Indonesia is quite low. Increased industry will cause environmental damage due to the waste generated and the resources used. environmental damage is increasingly felt, so the government makes the regulation that is Law No.3 of 2014 which contains one of them is the industrial obligation in protecting the environment. the current perceived environmental damage makes people increasingly concerned about the importance of maintaining the environment so as to make changes in product specifications demand. Rules and changes in demand, the industry must implement the aspect of sustainable supply chain management (SSCM). SSCM has an understanding that is integrating financial, environmental, and social in the supply chain. In the implementation of sustainable supply chain required Key Performance Indicator which aims to monitor and measure the performance of companies in the application of sustainable. KPI obtained from the implementation of the SCOR model is by mapping the business process of the company in SCOR model, so that obtained 14 KPI in accordance with the company's business processes and support the sustainable implementation. KPI obtained is verified on the company to obtain KPI that can be applied at this time and got 8 KPI selected which then done weighting using AHP, weight is used to calculate the sustainable performance of company. In performing monitoring and performance measurement tools are needed in monitoring. currently the company has not monitoring system so that company can not monitor and measure performance well which resulted barrier of company in applying of sustainable supply chain.
The impact of supply chain partnership and market driven strategy on consumer behavior in buying Vocaloid Hatsune Miku products
Authors: Damar Vicio Rizky , Hartono Markus
Published: September 2018

Hatsune Miku is the first virtual singer who is currently achieving success, even up to the world level. Miku has a large number of fansbase, like a famous singer. Its popularity also helps Crypton Future Media, as the company maker of Miku, to collaborate, forming a supply chain partnership with several big companies, to bring Miku into real products, which fans can have. This literature review explores this literature study explores Miku's development ever since it was created, until it became famous, and gave rise to a unique supply chain partnership. Researcher using systematic literature review method, with the aim of understanding how big the impact of Supply Chain Partnership and Market Driven from the success of virtual singer Hatsune Miku to consumer behavior, both from the general public and fans. The impact of this unique supply chain partnership is to make consumers loyal and feel close.
Failure Modes and Effects Analysis (FMEA) for evaluation of a sugarcane machine failure
Authors: Zadry Hilma Raimona , Saputra Dendi Adi , Tabri Agung Budiman , Meilani Difana , Rahmayanti Dina
Published: September 2018

The Failure Modes and Effects Analysis (FMEA) method has been widely recognized as a tool that systematically identifies the consequences and failures of the system or process, and reduces or eliminates the chances of the failure. This study applies that method to evaluate the causes of failure in the use of sugarcane machine that have been designed in the previous studies. FMEA approach anticipated the failures at the design stage, so that a more reliable and ergonomic design can be produced for future sugarcane machine. The potential failure identified from the machine consists of capacity issues, machine maintenance, preliminary treatment, and procedures of use. The study found that capacity issues are the priority problems that cause the machine failure. Then, this study proposed some actions to reduce the risk priority number (RPN) on 12 failures.
Development of quality improvement matrix: An integrated tools for quality improvement
Authors: Muhammad Katon , Karningsih Putu Dana
Published: September 2018

Continuous quality improvement is essential to ensure the competitiveness of manufacturing industries. Design of Experiments, Statistical Process Control and Failure Mode and Effect Analysis are common tools for improving quality. This study proposes a new tool that could encompass quality improvement steps comprehensively, namely Quality Improvement Matrix. This tool integrates several techniques which are House of Quality, Failure Mode and Effect Analysis (FMEA) and Root Cause Analysis. Quality Improvement Matrix covers identification of defects and its root causes, measuring the magnitude of defects (source of defects), formulating alternatives of solutions for reducing root cause of defects and selecting effective solutions to be implemented. Quality Improvement Matrix is developed by following a similar approach as House of Risk. Thus, it also consists of two matrixes that represent two major stages. The first stage is the identification and prioritizing root causes of defect. Then, the second stage is formulating and selecting solutions for improvements.
Occupational Health And Safety (OHS) management for employees on the risk of diseases due to the intensity of computer use in the workplace/industry
Authors: Putra Andika Bagus Nur Rahma , Ihwanudin M. , Mindarta Erwin Komara , Puspitasari Poppy , Pratama M. Mirza Abdillah
Published: September 2018

The research objectives of this study are: (1) urgent problems faced by employees when using computers; (2) computer components at risk of causing physical illness; and (3) mapping of disease experienced by OHS related employees on the computer. The subjects of this study are employees in three places of work / industry how many in Malang that work with computers with a duration of at least nine hours per day. The results of this study include: 1) the urgent problems experienced by the employees of the computer user include comfort (60%), position / feet distance (60%), monitor position at the work table (55%), mouse position (55%), (70%), rest breaks (75%), sitting position (70%), work desk condition (15%), room condition (25%), and rest break time (35%); 2) components on the computer that are at risk of causing computer-related OHS diseases that are computer CPU box (5%), computer monitor (25%), computer keyboard (10%), computer mouse (20%), computer cables (10%), and computer desk-chairs (30%); and 3) high-risk diseases suffered by employees of computer users include sicca-syndrome (55%), astenopia (70%), headache-comp (85%), Repetitive Strain Injuries (RSI) syndrom (55%), and Carpal tunnel syndrome (30%).
Optimizing coal blending quality through supplier selection and order allocation: A case of cement industry
Authors: Fatrias Dicky , Tri Putri Nilda , Akbar Pri Gustari , Fae Fidela Andari
Published: September 2018

Coal combustion plays an important role in the process of burning raw mix into cement clinker. However, ensuring a uniform coal quality is quite challenging especially when cement producer adopts multi-sourcing system where different suppliers involved to supply coal demand. This research explores the optimal coal blending quality problem in SP Co., as one of the largest cement industry in Indonesia, where the coal is supplied from several suppliers characterized by heterogenous and fluctuated coal quality. In detail, the problem is to select a set of suppliers and to determine optimal order allocation of coal for supplying three cement plants distinguished by certain requirement of coal specification under some realistic constraints such as quality of coal, allocated budget of purchasing and supplier capacity. A linear programming model is proposed to solve the formulated problem and sensitivity analysis is performed to examined the robustness of the model. Using real case data, we demonstrate the usefulness and applicability of our model.
Assessment of exposure packaging worker and designing work methods using OCRA index in fertilizer producer company
Authors: Fridayati Ainun Dwi , Wiediartini  , Amrullah Haidar Natsir , Shah Muhammad , Mudjiono Urip , Hidayat Edy Prasetyo
Published: September 2018

Repetitive tasks carried out by packaging workers of fertilizer producer company. These task led to some complains of pain and fatigue on upper body part of the workers based on Nordic Body Maps (NBM) questionnaire. This is because the workers work continuously for eight hours per shift and no recovery period. This study aims to determine risk level of musculoskeletal disorders and break time calculation. In this study, using Occupational Repetitive Actions (OCRA) index to reduce the risk level. The samples according to expert judgement criteria are three workers (packer clamper, packer tailor and loader). The improvement in this study is designing work methods with break time calculation. This improvement shows the risk reduction on the left hand of the packer clamper from 4,2 to 3,4 and the right hand from 9,9 to 8,2. Risk reduction on the left hand of the packer tailor from 3,44 to 2,2 and the right hand from 5,7 to 2,26 while the risk level on the left hand of loader from 1,4 to 0,87 and in the right hand from 2,17 to 1,18.
Utilization of the dethridge wheel as a low head power generator and loss analysis
Authors: Mugisidi Dan , Heriyani Oktarina , Luhung Rizal Andi , Andrian Moh. Ramdani Dwi
Published: September 2018

Utilization of low head flow water has long been used to generate power by using water wheels and low head turbines. Dethridge wheel which is usually used as a tool to measure the flow of water has also been studied its potential to become hydro power generation. Therefore, this study aims to compare performance between overshot Dethridge wheel and undershot Dethridge wheel. For this purpose, a small scale channel for the operation of a water wheel is equipped with a digital flow meter, a pump that has a debit of up to 25 l/s, a pony brake for a torque meter, and an inverter to adjust the flow rate by changing the pump rotation. The research was conducted at Laboratory of Mechanical Engineering, UHAMKA in Jakarta, Indonesia. Flow rates vary from 5 to 11 l/s with head of 10 cm and 537 cm. The efficiency of undershot and overshot, at the peak, are 21% and 18%, respectively.
Development of an open-loop ground source cooling system for space air conditioning system in hot climate like Indonesia
Authors: Jalaluddin  , Miyara Akio , Ishikawa Shohei , Tarakka Rustan , Amijoyo Mochtar Andi
Published: September 2018

Ground source cooling system (GSCS) is promising technology to serve cooling demands of buildings. This study presents a development of an open-loop GSCS for space air conditioning at Hasanuddin University Gowa campus. Experimental study was carried-out by pumping water from well of 57 m depth and flowing the water over a heat exchanger to cool refrigerant of air conditioning (AC) unit. The performance of AC unit was investigated under actual operation with various water flowrates. The temperatures of inlet and outlet water in the heat exchanger were also measured. The system operated from 11:00 until 18:00 o’clock local time with 3 (three) flowrates such as 3.6; 6.5 and 14.3 L/min respectively. In the low flowrate, the temperature of outlet water is approximately 37 °C. However, the compressor power is also increase significantly. The coefficient of performances (COPs) of the system in average are 2.9 in the low flowrate and 3.4 in the high flowrate. Also. the result shows that the utilization of GSCS is appropriated for cooling buildings in the hot climate like Indonesia.
CFD analysis of partial slip effect on the performance of hydrodynamic lubricated journal bearings
Authors: Muchammad  , Yunianto Bambang , Tauviqirrahman Mohammad , Wicaksono Widhi Ahmad , Jamari
Published: September 2018

Slip modification of the lubricated bearing such hydrophobic coating has proven to improve the hydrodynamic performance. The present paper investigates the effect of partial slip on the journal bearing performance using computational fluid dynamic (CFD) approach. The eccentricity ratio and the placement of slip area are of particular interest. It was shown that the partial slip placement on the convergent region of the bearing generally improves the hydrodynamic performance lubrication by increasing load support. It was also found that introducing partial slip on the divergent area decreases the lubrication performance of journal bearing.
Development of Aceh iron sand to produce pig iron: studies on hardness properties
Authors: Sayuti M , Ibrahim Akhyar , Yusuf Muhammad , Putra Reza
Published: September 2018

Aceh is one of provinces in Indonesia that produces iron sand. However, Aceh iron sand has been sent to other countries in the raw form instead of the processed one, which actually can add significant economic value to the minerals and eventually can contribute to the increased Aceh’s PAD (Regional Own-source Revenue) as well as support national industry. A study has been carried out to develop of Banda Aceh iron sand to produce pig iron using reduction processes. Hardness tests and characterization of mineral were performed and the results are reported. The results show that the average hardness properties of both the sponge and the pig iron were 282, 22 HV and 377,178 HV, respectively. Chemical composition of pig iron is 2,71%C, 2,5%Si, 0,13%S, 0,12%Cr, 0,54%Mn, 0,74%Ti, 0,94%Al, 0,2%V and 92%Fe.
Microstructure and mechanical characteristics of hot forged lateritic steels
Authors: Herbirowo Satrio , Hakim Luqmanul , Adjiantoro Bintang
Published: September 2018

The current development of steel industry has constraints on the availability of raw materials, so we have developed local raw materials that are lateritic steels as a high potential for alternative manufacturing of steel. This research was conducted to understand the characteristics of lateritic steel through hot forging process by the mechanical and microstructure behaviour. The research methodology was chained by variety of preheating temperature of 800; 1000; 1200 °C and forging force from 0 until 1000 kilonewton. In case of hot forging values was obtained the impact and hardness properties also microstructure that compared with as-cast steels. The results of impact strength increased by 81.83% at the temperature of 1200 °C and the hardness increased by 4.99% at 1000 °C, for the microstructure analysis was produced the ferrite and pearlite phases with the fine grains. The chemical composition of steel is classified in low carbon steel included in lateritic steel it contains low alloy 1.78 Ni and 0.553 Cr %wt.
Effects of brass addition on the flexural strength and microstructure of porous clay/brass composites
Authors: Amin Muh , Pribadi Rubijanto Juni , Jamasri
Published: September 2018

Porous clay/brass composite was fabricated by an extrusion process with the addition up to 40 wt.% brass has been successfully done. Clay 80 wt.%, TiO210 wt.%, active carbon 5 wt.%, and polyvinyl alcohol 5 wt.% have been prepared as a matrix for this study. All of wt.% has been mentioned excluding solvent water 20 wt.% and lubricant (glycerin oil, 1 wt.%). Before the moulding process, all the raw materials were mixed to obtain homogeneity. Blending process was done by adding 20 wt.% water until the mixture turned into dough. After the moulding process, the specimens were dried at room temperature for 48 hours, and then they were sintered at 800°C for 1 hour in an electrical box furnace with heating rate 1°C/min and holding time of 1 hour. The flexural strength of specimens and the microstructure of the sintered porous bodies were also investigated. The addition of 20 wt.% brass on the composite materials showed a higher on the strength, that is 0.6 MPa and 0.38 MPa on yield strength.
Morinda citrifoliia L. as a renewable raw material for surface active agent
Authors: Trismawati  , Wikanaji D.
Published: September 2018

Surface active agent (surfactant) is a substance or a blend of substances that lower the surface tension or interfacial tension between two liquids. It contains both hydrophobic groups (its tail) and hydrophilic groups (its head). Surfactants lower the surface tension of a liquid by spreading spontaneously over its surface. To understand its suitability for raw material of surfactant, the seed of Morinda citrifolia L is extracted for its fatty acid contents and evaluated for its spreading ability into other liquid. Its fatty acid contents are analyzed by FTIR and GCMS method and its spreading ability is evaluated by its diffusion characteristic using Helle Shaw Cell. From FTIR it is known that the oil seed of Morinda citrifolia has functional groups suitable for the hydrophobic part of surfactant. From GCMS it is known that the seed of Morinda citrifolia L contains huge amount of poly unsaturated fatty acid (PUFA) of C19:2 suitable for the hydrophobic part of surfactant. From diffusion experiment using Hele Shaw Cell it is known that the spreading ability of its PUFA in oil phase is approaching its commercial synthetic surfactant has but it is not in water phase.
Effect of peroxide treatment on the structure and transparency of bacterial cellulose film
Authors: Suryanto Heru , Sutrisno Tito Arif , Muhajir M. , Zakia Neena , Yanuhar Uun
Published: September 2018

The cellulose extracts from plants are need of energy and have potential in damaging the environment so that an alternative cellulose source with more efficient results is by using bacteria to produce the cellulose fibers. This study aims to determine the effect of hydrogen peroxide (H2O2) treatment on the structure and transparency of biopolymer bacterial cellulose film (BCF). The method used is the making of BCF by utilizing pineapple peel extract and then cooking at 80°C for 120 min. with H2O2 concentration of 0%, 2.5%, 5%, and 7,5%. Drying is done in the electric oven and then observed the structure and morphology using X-ray diffraction and transparency test, respectively. The result of structure observation shows that the intensity of the highest diffraction peak lies at a diffraction angle of 22° achieved at 5% peroxide treatment with crystallinity and crystal index of 85.1% and 82.4%, respectively. Transparency testing shows that the higher the concentration of peroxide used, the better the transparency.
The inhibitive effect of tannin in Psidium guajava leaves towards 304SS corrosion in concentrated HCl
Authors: Ganda Andita N. F. , Andoko  , Setyarini P. H. , Gapsari Femiana
Published: September 2018

Tannin isolated from Psidium guajava leaves are developed to enhance the corrosion protection of austenitic stainless steel. It is used as a green inhibitor, extracted from Psidium guajava which grow in East java, Indonesia. In the present work, the corrosion inhibition properties of the tannin inhibitors were investigated in 3M HCl by polarization potentiodynamic measurements. The result reveals that tannin 1g/L could enhance the inhibition efficiency up to 91.81%.
Multi objective optimization for kerf and material removal rate in wire electrical discharge machining using Taguchi method combined grey relational analysis
Authors: Rupajati Pathya , Rasyid M. Kurniadi , Nurdin Ali
Published: September 2018

This paper investigated the multi performance characteristics of wire electrical discharge machining for an optimal machining parameters to get low kerf and high material removal rate at the same time. The machining parameters i.e arc on time, on time, servo voltage and wire feed were used in this experiment. Based on L9 orthogonal array, the signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) was used to study the machining parameters of DIN 1.2510 tool steel. Multi response characteristics were solved by Taguchi method combined grey relational analysis. Experimental results are provided to demonstrate the effectiveness of this method i.e. kerf decreased from 354 μm to 345 μm, while material removal rate (MRR) increased from 9,313 mm3/min to 13,989 mm3/min. From the optimization result validated in the confirmation experiment the machining parameters combination that could produce the optimum responses are arc on time of 2 A, pulse on time of 8 μs, servo voltage 80 V and wire feed 60 mm/min.
An Effect of Electric Current Variations and Wire Feed Rate on Low Carbon Steels Toward Tensile Strength on The Result of Gas Metal Arc Welding
Authors: Hardiansyah Taufik , Imron Moch Rofi , Handoko Johan , Solichin  , Qolik Abdul
Published: September 2018

The purpose of this study was to find out the tensile strength of GMAW welded carbon steel with electric current variation and wire feed rate. The research method used was experimental research with electric current variation of 120 A, 140 A, and 160 A and variation of wire feed rate 4 m/min and 5 m/min. The tensile strength test of sample was done by ASTM E8 / E8M-09 test standard. The result showed that the electric current variation and wire feed rate in welding of carbon steel with GMAW welding gave effect on the value of tensile strength which was varied. The electric current of 120 A and the wire feed rate of 4 m/min obtained the highest tensile strength of 52.67 kgf/mm2 and welding with electric current of 120 A and wire feed rate of 5 m/min obtained the lowest tensile strength of 48.33 kgf/mm2.
Strength analysis of connecting rods with pistons using finite element method
Authors: Andoko  , Saputro Nanang Eko
Published: September 2018

A connecting rod is the core component of an engine which has a function to transmit power released from combustion from the piston to the crankshaft. Deformation is the most commonly occurring damage to connecting rods. The connecting rods made of structural steel, aluminium alloy and titanium alloy were designed using Autodesk Inventor and analysed using ANSYS. The simulations showed the following results. The connecting rod made of structural steel had the highest maximum stress of 82.791 MPa. The connecting rod made of aluminium alloy had the highest maximum deformation of 0.84071 mm. The three connecting rod materials had the same maximum safety factor, i.e. 15.
Elastic linear analysis of CNC micro blanking machine using finite element method
Authors: Didin Zakariya Lubis , Suprayitno  , Khoiruddin A. , dan Mukhamad Andi Firismanda
Published: September 2018

This study has developed Micro Punch CNC Machine design by optimizing the function of the actuator axis implemented to make an implant plate. This research aimed to plan the simulation of CNC machine construction strength using the blanking operation application. Finite element method (FEM) was used to analyze the material strength. The research results showed that the maximum stress occurring at the punch tools was 428.17 MPa with the thickness of 0.6 mm and the maximum thickness of workpiece allowed in making the implant plate was 1.4 mm with the maximum stress of 999.09 MPa. The obtained data indicate that the most effective material to be used as the material construction in CNC micro blanking machine is St42. This case is proven by the result of the power to resist the stress and the value of maximum deformation from the comparison of both materials.
Demenz mit Lewy-Körpern
Authors: Dodel Richard , Koschel Jiri , Lorenzl Stefan , Levin Johannes , van Eimeren Thilo , Höglinger Günter
Published: September 2018

Die Demenz mit Lewy-Körpern ist histopathologisch durch die Ablagerung von α-Synuclein in Einschlusskörpern gekennzeichnet. Für die klinische Diagnose wird eine fortschreitende Demenz sowie das Auftreten von Fluktuationen der Kognition, früh im Krankheitsverlauf auftretende visuelle Halluzinationen, REM-Schlafverhaltensstörungen sowie die Symptome eines Parkinson-Syndroms zugrunde gelegt. Anhand der 2017 erschienenen neuen Kriterien soll eine bessere Trennung von anderen neurodegenerativen Erkrankungen mit Demenz möglich sein. Therapiekonzepte beinhalten die Behandlung der motorischen sowie der kognitiven Leistungseinbuße sowie die psychologischen und Verhaltenssymptome. Gegenwärtig stehen nur wenige Studien für dieses Krankheitsbild zur Verfügung, so dass Evidenz-basierte Therapieansätze nur bedingt möglich sind.
Long-Term Effects on Volume Change in Musculocutaneous Flaps after Head and Neck Reconstruction
Authors: Sakakibara Akiko , Kusumoto Junya , Sakakibara Shunsuke , Hasegawa Takumi , Akashi Masaya , Minamikawa Tsutomu , Furudoi Shungo , Hashikawa Kazunobu , Komori Takahide
Published: September 2018

Objective Musculocutaneous flap reconstruction surgery is one of the standard procedures following head and neck cancer resection. However, no previous studies have classified flaps in terms of muscle and fat or examined them after long-term follow-up. The purpose of this study was to estimate the fat and muscle volume changes in musculocutaneous flaps during long-term follow-up.

Methods We conducted a retrospective analysis of 35 patients after musculocutaneous flap reconstruction. The total, fat, and muscle volumes of the musculocutaneous flaps were measured using 3-dimensional images. Changes in flap volumes over time (1 month, 1 year [POY1], and 5 years [POY5] postoperatively) were assessed. Flap persistence was calculated using flap volumes at 1 month after reconstruction for reference.

Results Flap persistence at POY5 was 42.0% in total, 64.1% in fat, and 25.4% in muscle. Muscle persistence was significantly decreased (p < 0.0001). In a multiple regression analysis, decreased body mass index (BMI) of ≥ 5% influenced fat persistence less than muscle persistence at POY1; however, there was no significant difference at POY5. Postoperative radiation therapy was associated with a significant decrease in total flap persistence at POY1 (p = 0.046) and POY5 (p = 0.0097). Muscle persistence significantly decreased at POY5 (p = 0.0108). Age significantly influenced muscle volume at POY1 (p = 0.0072).

Conclusion Reconstruction flaps are well-preserved with high fat-to-muscle ratios. Recommendations for weight maintenance are necessary for patients less than 2 years after surgery due to the influence of BMI on fat persistence. Radiation therapy is necessary for some patients based on their disease state. Intensity-modulated radiation therapy can be offered to reduce scattering irradiation to normal tissues.
Vitamin D in Orthopädie und Unfallchirurgie
Authors: Maus U. , Lazovic D. , Seeger J. B. , Roth K. E. , Kurth A. A. , Horas K. , Maier G. S.
Published: September 2018

Der Einfluss von Vitamin D im Rahmen der Pathogenese von muskuloskeletalen Erkrankungen ist aktuell ein Thema von hohem wissenschaftlichem Interesse. Nahezu alle Altersschichten der Bevölkerung sind von einer Vitamin-D-Unterversorgung gefährdet. Vitamin D ist ein essenzieller Faktor für die Knochengesundheit und Muskelfunktion, beides Kernelemente der Orthopädie. Zahlreiche Studien zeigten einen möglichen Zusammenhang zwischen dem Serum Vitamin-D-Spiegel und orthopädisch/traumatologischen Krankheitsbildern. In diesen Beobachtungsstudien wurden diverse negative Auswirkungen eines Vitamin-D-Mangels auf das Ergebnis nach Endoprothesenoperationen und den Verlauf orthopädisch/traumatologischer Krankheitsbilder beschrieben. Die vorliegende Arbeit soll einen Überblick über dieses stetig wachsende Themengebiet bieten.
The Role of Vitamin D and the Vitamin D Receptor in Bone Oncology
Authors: Holzapfel B. M. , Jakob F. , Kurth A. A. , Maier G. , Horas K.
Published: September 2018

Vitamin D deficiency is a global health problem of enormous and increasing dimensions. In the past decades, numerous studies have centered on the role of vitamin D in the pathogenesis and course of many diseases including several types of cancer. Indeed, vitamin D has been widely acknowledged to be involved in the regulation of cell proliferation, differentiation and apoptosis in numerous cancer cells. While the full range of molecular mechanisms involveld in cancer cell growth and progression remains to be elucidated, recent research has deepened our understanding of the processes that may be affected by vitamin D or vitamin D deficiency.

In this review, we consider the properties of bone that enable cancer cells to grow and thrive within the skeleton, and the role of vitamin D and the vitamin D receptor in the process of primary and secondary cancer growth in bone.