bluuebunny/crossref_metadata_2025 huggingface dataset:
SODIUM ABSORPTION SYSTEMS TOWARD SN Ia 2014J ORIGINATE ON INTERSTELLAR SCALES*
Authors: Maeda K. , Tajitsu A. , Kawabata K. S. , Foley R. J. , Honda S. , Moritani Y. , Tanaka M. , Hashimoto O. , Ishigaki M. , Simon J. D. , Phillips M. M. , Yamanaka M. , Nogami D. , Arai A. , Aoki W. , Nomoto K. , Milisavljevic D. , Mazzali P. A. , Soderberg A. M. , Schramm M. , Sato B. , Harakawa H. , Morrell N. , Arimoto N.
Published: January 2016

Na i D absorbing systems toward Type Ia supernovae (SNe Ia) have been intensively studied over the last decade with the aim of finding circumstellar material (CSM), which is an indirect probe of the progenitor system. However, it is difficult to deconvolve CSM components from non-variable, and often dominant, components created by interstellar material (ISM). We present a series of high-resolution spectra of SN Ia 2014J from before maximum brightness to ≳250 days after maximum brightness. The late-time spectrum provides unique information for determining the origin of the Na i D absorption systems. The deep late-time observation allows us to probe the environment around the SN at a large scale, extending to ≳40 pc. We find that a spectrum of diffuse light in the vicinity, but not directly in the line of sight, of the SN has absorbing systems nearly identical to those obtained for the “pure” SN line of sight. Therefore, basically all Na i D systems seen toward SN 2014J must originate from foreground material that extends to at least ∼40 pc in projection and none at the CSM scale. A fluctuation in the column densities at a scale of ∼20 pc is also identified. After subtracting the diffuse, “background” spectrum, the late-time Na i D profile along the SN line of sight is consistent with profiles near maximum brightness. The lack of variability on a ∼1 year timescale is consistent with the ISM interpretation for the gas.
ABSORPTION OSCILLATOR STRENGTHS FOR THE
(3, 4, 6)–
(10, 13, 20)–
AND
(1)–
PROGRESSIONS IN N2
Authors: Lavín C. , Velasco A. M.
Published: January 2016

Absorption oscillator strengths, calculated with the molecular quantum defect orbital method, for the

(3)–

= 0–12),

(4)–

= 0–12),

(6)–

= 0–12),

(10)–

= 0–12),

(13)–

= 0–12),

(20)–

= 0–12), and

(1)–

= 0–12) bands of molecular nitrogen are reported. The Rydberg–valence interaction between states of

symmetry has been treated through an interaction matrix that includes vibrational coupling. Due to the homogeneous interaction, the intensity distribution of the bands within each progression deviates from the Franck–Condon predictions. The present results for vibronic transitions from the

ground state agree rather well with reported high-resolution measurements. As far as we know, f-values for bands originating from v″ > 0 vibrational levels of the electronic ground state are reported here for the first time. These data may be useful in the interpretation of the extreme ultraviolet spectra from Earth’s and Titan’s atmospheres, in which several bands of the

and

progressions have been identified.
FERMI-LAT OBSERVATIONS OF SUPERNOVA REMNANT G5.7–0.1, BELIEVED TO BE INTERACTING WITH MOLECULAR CLOUDS
Authors: Joubert Timothy , Castro Daniel , Slane Patrick , Gelfand Joseph
Published: January 2016

This work reports on the detection of γ-ray emission coincident with the supernova remnant (SNR) G5.7–0.1 using data collected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The SNR is believed to be interacting with molecular clouds, based on 1720 MHz hydroxyl (OH) maser emission observations in its direction. This interaction is expected to provide targets for the production of γ-ray emission from π
0-decay. A γ-ray source was observed in the direction of SNR G5.7–0.1, positioned near the bright γ-ray source SNR W28. We model the emission from radio to γ-ray energies using a one-zone model. Following consideration of both π
0-decay and leptonically dominated emission scenarios for the MeV–TeV source, we conclude that a considerable component of the γ-ray emission must originate from the π
0-decay channel. Finally, constraints were placed on the reported ambiguity of the SNR distance through X-ray column density measurements made using XMM-Newton observations. We conclude G5.7–0.1 is a significant γ-ray source positioned at a distance of ∼3 kpc with luminosity in the 0.1–100 GeV range of L

γ
 ≈ 7.4 × 1034 erg s−1.
¿Qué distancia recorre el consumidor para comprar un coche?
Authors: Rodríguez Rodríguez Vicente , Olarte Pascual Cristina , Saco Vázquez Manuela
Published: January 2016

We have noticed that in order to locate a net of dealers it is necessary to take into account the travel distances made by buyers. Travel distances and buyer habits are determined by their environment and living area. This investigation focuses on the differences between rural and urban journeys made by consumers in Andalucía in order to purchase a car in order to show that it is possible to reduce the average distance in journeys by applying location-allocation models in the geographical location of dealers. The result of this investigation shows that the application of p-median model is useful for the manufacturer executives in the automotive companies and also for the dealers, because it lets optimize the location of a commercial network.
Mobile Device Trends in Orthopedic Surgery: Rapid Change and Future Implications
Authors: Andrawis John P. , Muzykewicz David A. , Franko Orrin I.
Published: January 2016

Mobile devices are increasingly becoming integral communication and clinical tools. Monitoring the prevalence and utilization characteristics of surgeons and trainees is critical to understanding how these new technologies can be best used in practice. The authors conducted a prospective Internet-based survey over 7 time points from August 2010 to August 2014 at all nationwide American Council for Graduate Medical Education–accredited orthopedic programs. The survey questionnaire was designed to evaluate the use of devices and mobile applications (apps) among trainees and physicians in the clinical setting. Results were analyzed and summarized for orthopedic surgeons and trainees. During the 48-month period, there were 7 time points with 467, 622, 329, 223, 237, 111, and 134 responses. Mobile device use in the clinical setting increased across all fields and levels of training during the study period. Orthopedic trainees increased their use of Smartphone apps in the clinical setting from 60% to 84%, whereas attending use increased from 41% to 61%. During this time frame, use of Apple/Android platforms increased from 45%/13% to 85%/15%, respectively. At all time points, 70% of orthopedic surgeons believed their institution/hospital should support mobile device use. As measured over a 48-month period, mobile devices have become an ubiquitous tool in the clinical setting among orthopedic surgeons and trainees. The authors expect these trends to continue and encourage providers and trainees to be aware of the limitations and risks inherent with new technology. [
Orthopedics.
2016; 39(1):e51–e56.]
Giant Cell Tumors of the Bone With Pulmonary Metastasis
Authors: Chen Chun-Chieh , Liau Chi-Ting , Chang Chih-Hsiang , Hsu Yung-Heng , Shih Hsin-Nung
Published: January 2016

Giant cell tumors of the bone are benign but locally aggressive, and they rarely metastasize to the lungs. The purpose of this study was to retrospectively review the clinical presentation, long-term outcomes, and treatment of pulmonary metastasis of these tumors. Between 1991 and 2004, a total of 168 patients with giant cell tumors of the bone were treated at the authors' institution, 7 of whom developed lung metastasis. Four of the 7 patients were men, and mean age of these patients at initial surgery was 40 years (range, 19–56 years). All patients underwent wide excision and reconstruction or curettage and bone grafting for the bony lesions. Lung metastases were detected at a mean of 44 months after the treatment of bone lesions. Five patients had multiple metastases, and 2 had solitary pulmonary metastases. Six of these patients underwent delayed treatment, locally aggressive, or multiple recurrent and surgical procedures. All of the aforementioned procedures had similar risk factors to those previously reported in the literature. One patient had multiple giant cell tumors of the bone. At last follow-up, 2 patients had died due to complications from the pulmonary metastases or chemotherapy. One patient underwent a metastasectomy 4 years after treatment due to the progression of pulmonary metastasis. The remaining 4 patients were alive and healthy after chemotherapy or conservative treatment. Therefore, early detection, adequate treatment of the primary bone lesion, conservative treatment of lung metastases, and regular long-term follow-up are recommended. [
Orthopedics.
2016; 39(1):e68–e73.]
Public and common goods in the cultural landscape // Javno in skupno dobro v kulturni pokrajini
Authors: Šmid Hribar Mateja , Bole David , Urbanc Mimi
Published: January 2016

The main purpose of this paper is to review the literature and national documents, and define the meaning and roles of various types of good in the rural cultural landscape. We identified four main categories: private good, toll good, common good, and public good. The scope, uses, and benefits of goods in the cultural landscape change over time due to, inter alia, socio-political processes and formal (non)recognition at the institutional level. Further, we discuss how public good and common good benefit the community, and the necessity of sound management and conservation of common good. In the context of public good, supporting, regulating, and cultural ecosystem services are becoming increasingly important. They are non-subtractable, but they are inextricably linked to private land. As there are many points of conflict in the use of common and public goods, their protection should be provided in the relevant legislation.Glavni namen prispevka je pregled strokovne literature in državnih dokumentov ter opredelitev pomena in vloge različnih tipov dobrega v podeželski kulturni pokrajini. Prepoznali smo štiri glavne kategorije: zasebno, plačljivo, skupno in javno dobro. Obseg, način rabe in koristi dobrega se v kulturni pokrajini spreminjajo skozi čas, tudi zaradi družbeno-političnih procesov in formalnega (ne)prepoznanja na institucionalni ravni. Poleg tega razpravljamo, kako javno in skupno dobro prinašata skupnosti koristi ter o nujnosti premišljenega upravljanja in ohranitvi skupnega dobrega. V kontekstu javnega dobrega so podporne, uravnalne in kulturne ekosistemske storitve vse pomembnejše. Z rabo sicer ne upadajo, a so neločljivo povezane z zasebnimi zemljišči. Ker obstajajo mnoge točke konflikta v rabi skupnega in javnega dobrega, je njegova zaščita pomembna tudi na zakonodajni ravni.
Determination of Dynamic Parameters for Underwater Robots with Crawler Drives
Authors: Kurc Krzysztof , Szybicki Dariusz
Published: January 2016

The paper presents methods used to determine the parameters necessary to build a mathematical model of an underwater inspection robot with a crawler drive. The parameters present in the dynamics equation will be determined by means of advanced mechatronic design tools, including: CAD/CAE software and MES modules. The robot dynamics are described by means of type II Lagrange equations for a non-holonomic system. The details of the kinetic and dynamic equation derivation are highly complex and exceed the scope of this paper. In this paper, the authors concentrate on the methods of determining such dynamic equation parameters as: hydrodynamic resistance factor, precise robot volume and weight, frontal cross-sectional surface and mass moments of inertia.
Globalized Dual Heuristic Dynamic Programming in Control of Robotic Manipulator
Authors: Szuster Marcin , Gierlak Piotr
Published: January 2016

The article focuses on the implementation of the globalized dual-heuristic dynamic programming algorithm in the discrete tracking control system of the three degrees of freedom robotic manipulator. The globalized dual-heuristic dynamic programming algorithm is included in the approximate dynamic programming algorithms family, that bases on the Bellman’s dynamic programming idea. These algorithms generally consist of the actor and the critic structures realized in a form of artificial neural networks. Moreover, the control system includes the PD controller, the supervisory term and an additional control signal. The structure of the supervisory term derives from the stability analysis, which was realized using the Lyapunov stability theorem. The control system works on-line and the neural networks’ weight adaptation process is realized in every iteration step. A series of computer simulations was realized in Matlab/Simulink software to confirm performance of the control system.
Mission Planning Training Simulator of Autonomous Surface Vehicle (ASV)
Authors: Kitowski Zygmunt
Published: January 2016

The paper presents the architecture of the mission planning training simulator of the autonomous surface vehicle (ASV) "Edredon". The structure of the simulator is based on a mission planning site, designed by the Polish-Japanese School of Computing, located in the USV command post. Its software allows not only for planning the ASV’s route but also for implementing the training process of an operator preparing the route.
Ship Motion Control System for Replenishment Operation
Authors: Gierusz Witold , Miller Anna
Published: January 2016

Underway Replenishment is a procedure whose importance is rising in shipping. It is applied both to the naval and civil vessels. That is the reason why research in this area was undertaken. In this paper idea of the ship motion control system for replenishment operations was presented. The outline of the system is described in a detail way. This system incorporates Model Predictive Controller as a main part of the proposed algorithm. The other important part of the control system is a reference trajectory for the approaching ship generation. Conducted computer simulations prove that there is a possibility to synthesize MPC controller to maintain the pair of ships parallel motion during the UNREP operation.
The Use of Hall Effect Sensors in Magnetic Levitation Systems
Authors: Sibilska-Mroziewicz Anna , Czubaj Sławomir , Ładyżyńska-Kozdraś Edyta , Sibilski Krzysztof
Published: January 2016

This paper presents a new method of non-contact measurement and control of the magnetic field strength. The article discusses at first magnetic levitation phenomena and commercial Mag-Lev suspensions systems. Then it explains the Hall effect physics and example use of Hall effect sensor in educational magnetic levitation device. Next it lists some example constructions of Hall effect sensors. Finally it reveals potential new use of Hall-sensor in control system of unmanned aircraft catapult using Meissner effect.
Optimal Compensator for Anti-Ship Missile with Vectorization of Engine Thrust
Authors: Nocoń Łukasz , Koruba Zbigniew
Published: January 2016

This paper presents a method of controlling an anti-ship missile with the use of the linear-quadratic regulator (LQR). The equations of dynamics of the flight were linearized and written in the form of equations of state. To control the anti-ship missile, a double executive gas-dynamic (moveable nozzle of exhaust gases) and aerodynamic (moveable control surfaces) system is applied. The missile flight is considered in a three dimensional space, whereas the controlling vector is comprised of four components: two components to control the height of the flight and two components to control the direction of the flight. The results are presented in a graphic form.
Design of Radio Digital Mobile Communications in Conditions of the Polish Railway
Authors: Siergiejczyk Mirosław
Published: January 2016

The article presents selected issues related to the analysis of GSM-R network and issues of planning and dimensioning of this network in terms of providing opportunities for data and voice transmission. The synthetic description of the system structure, a set of available services and the means of data transmission were presented. Then, certain conditions that should be taken into account in the connection budget were specified. Requirements for network dimensioning for determining the operating capacity of the network were specified. The volume of the telecom traffic generated within the base station transceiver affects not only the number of resources necessary to handle the traffic, but also implies the number of frequency channels necessary to be allocated.
Verification of a 2–Phase, Zero-Dimensional Model of a Multifuel Compression-Ignition Engine in Single Fuel Operation
Authors: Mikulski Maciej , Wierzbicki Sławomir , Piętak Andrzej
Published: January 2016

Improving the efficiency or work and reducing the emissions of toxic substances into the atmosphere are the two key directions of development of modern combustion engines. Improvement of engine efficiency is feasible only by increasing the precision of control thereof, which necessitates long-term operating tests. Regrettably, due to complexity of processes taking place during the combustion of fuel, these phenomena can only be tested on simulation models, based on a mathematical description of the phenomena.This paper presents the results of verification tests of the developed fuel combustion model in a multifuel compression-ignition engine for an engine running only on diesel fuel.
Economic Analysis Using Net Present Value and Payback Period: Case Study of a 9kWp Grid-Connected PV System at UTM, Johor Bahru Campus
Authors: Almaktar Mohamed , Abdul Rahman Hasimah , Hassan Mohammad Yusri
Published: January 2016

An economic study for the photovoltaic (PV) projects by the PV installer is essential to avoid the risk that may incur from the investment. This paper discusses the economic analysis of PV installations specifically for the grid connected (GC) systems. The case study is the 9 kW Solar-Home UTM system which is planned to be a showcase GC zero energy house. The house will be able to sell the excess energy back to the grid according to the Malaysian Feed-in Tariff (FiT) implemented in 2012. The economic study conducted is based on the Net Present Value (NPV) and the Pay-Back Period to determine the profitability and viability of the project. The study is believed to encourage and initiate the public to build a successful investment and contribute in the development and deployment of new clean energy sources.
Energy Analysis of Efficient Lighting System Design for Lecturing Room Using DIAlux Evo 3
Authors: Kamaruddin Mohd Athir , Arief Yanuar Z. , Ahmad Mohd Hafizi
Published: January 2016

Rate of electricity consumption is increasing due to the increasing demand every year, while the supply of natural resources is significantly reduced. This is a factor why electricity tariffs are increased and it would affect the improvement of living standards. The lighting system is one of the important elements of the building design. Effective and efficient strategy of lighting, includes natural daylighting, appropriate level of illumination, and low energy consumption. A significant cost saving can be achieved if the designers know how to design a lighting system effectively and efficiently. Therefore, the appropriate design of lighting system which meet the standard was proposed in this project. The objective of this research is to perform energy analysis of lighting system design for lecture room. The lecture room at UTM SPACE building in Kuala Lumpur was taken as a case study. Type of lighting used, existing room design, and lighting technology in the market are identified prior to the beginning of the present study. After that, the system design is implemented using the manual calculation based on lumen method and the simulation is done using DIAlux Evo 3 and AutoCAD. Two type of lighting products are compared in terms of energy consumption and cost: the compact fluorescent lamp (CFL) and the light emitting diode (LED). Then, comparison of results was performed to obtain the best lighting system. The results revealed that LED provides energy cost savings of 30% to 50% annually compared to CFL. The prediction from DIAlux Evo 3 simulation is more accurate compared to the manual calculation.
A Review of Uncertainty Sources on Weather Ground-Based Radar for Rainfall Estimation
Authors: Nikahd Ali , Hashim Mazlan , Nazemosadat Mohammad Jafar
Published: January 2016

Efforts in hydrometeorology are concentrated on finding the causes of the ground based radar uncertainty sources for rainfall estimation recently. The error sources are interactions between radar with atmosphere and topography. Radar singly often covers systematic error whereas atmospheric and topographic errors are relevant to location and precipitation pattern. This article reviews uncertainty sources on weather ground-based radar in order to rainfall estimation that have been discussed in nine main categories includes; the range effects, radar signal attenuation, beam blockage, vertical air motion and precipitation drift, ground clutter, anomalous propagation, vertical variability of the precipitation system, variability of the Z-R relationship and bright band. Topographic errors such as ground clutter and beam blockage primarily can be eliminated by attentive in site selection. Atmospheric errors such as vertical air motion and precipitation drift can filter or eliminated by calibration methods. Systematic errors include radar signal attenuation and anomalous propagation is the result of structural changes in the radar waves in space. Thus, this review is explored the characteristics of uncertainty error resources and a comprehensive appraisal of experimental procedures is provided.
Review of Oil-Filled Transformer Monitoring Technology for New User
Authors: Muhamad Nor Asiah , Kamarden Hanafiah
Published: January 2016

Distribution and power transformer is the essential part of electrical power transmission system. Abnormalities occur at the transformer can be interpreted and analysed to get the cause of faults, thus it can be further studied for monitoring ageing and condition of the transformer. A lot of studies have been done to detect as many abnormalities that can possibly arise in a transformer. For inexperienced user, it can be a bit of overwhelming to choose which studies that they can refer to. Numerous techniques and methods has been used for transformer monitoring till date and still being improved which includes: Common Electrical Tests, Power and Dissipation Factor Measurement, Partial Discharge (PD) Analysis, Frequency Response Analysis (FRA), Dielectric Response Analysis (DRA), Dissolved Gas Analysis (DGA), Dielectric Breakdown Voltage, Oil Resistivity, and Karl Fischer Titration. These techniques and methods are developed to monitor and analyse the common part of transformer which are winding, core, bushing, insulation oil, and insulation paper. This paper reviews the current improved techniques and methods in transformer monitoring according to the technology, accuracy, complexity, and cost for the past five years. A few methods and techniques can be appointed to each of classified user as a beginner, intermediate and competent. Finally, this paper suggests more improvement to be studied on the existing established methods. Some of the techniques can be combined to create a better accuracy and efficiency for fault identification, ageing estimation and condition monitoring.
Investigation on Equipment Failure Mode and Causes Using Infra-Red Thermovision Camera Images for High Voltage Electrical Connection
Authors: Osman Amir Hamzah , Adzis Zuraimy , Arief Yanuar Z. , Muhamad Nor Asiah
Published: January 2016

High voltage (HV) electrical connection hot spot scanning and monitoring is important to ensure the availability, continuity and reliability of electrical supply. The aim of this research work is to investigate HV electrical connection apparatus using infra-red thermovision camera. A database of hot spot images from infra-red thermovision scanning is needed to perform an analysis to ascertain the mode and causes of the hot spot. Eight numbers of Tenaga NasionalBerhad’s (TNB) main intakes (PMU) with different location, environment type, and load were selected to get various data to be formed a hot spot database. The database consist of HV electrical apparatus scanning image using infra-red thermovision camera to investigate the hot spot temperature reading, location and bay in dedicated PMU. The data collected from year 2010 until 2013 were analyzed to ascertain the failure modes of the HV electrical connection apparatus according to TNB condition monitoring unit standards. All objectives were achieved by performing the database, equipment failure mode and causes were ascertained are related to the load (MW) and bad workmanship during erection process. Connection apparatus with high hot spot reading were investigated, repaired or taken out from services if damage, and replaced. Solutions were proposed on the damage electrical HV electrical connection apparatus depends on the source of the problem.
Dilatometry Coupled with Mass Spectrometry as Instrument for Process Control in Sintering of Powder Metallurgy Steels
Authors: Gierl-Mayer Christian , Danninger Herbert
Published: January 2016

The production of ferrous powder metallurgical parts by the press-and-sinter route becomes more and more attractive. Today, parts are produced for loading requirements that until now only could be fulfilled by conventional produced steel components. The high mechanical properties that must be attained require the use of alloying elements so far not common in powder metallurgy because of their high affinity for oxygen. The sintering of chromium containing steels is a challenge for the whole production process, because the reduction of the surface oxides is critical for successful sintering.Dilatometry can be a useful instrument to control the sintering behaviour of the materials, especially the combination with mass spectrometry allows analysing the very complex sintering process and simultaneously monitoring the solid-gas reactions. This work shows that the sintering atmosphere plays a major role in the entire process. Degassing and deoxidation processes during sintering are demonstrated for different alloying systems (Fe, Fe-C, Fe-Mo-C, Fe-Cr-Mo-C). Dilatometry coupled with MS is shown to be a very good instrument for process control of the sintering process. The generated analytical data can be related to the mechanical properties of the sintered steels if the size of the specimen is large enough.
Rheology and Kinetics of Pressure Sintering
Authors: Kovalchenko M.S.
Published: January 2016

The rheological viscous flow model of deformable, irreversibly compressible, porous body based on mechanics of continua, and creep theory of crystalline materials, is used to describe quantitatively the sintering of powder materials with pressure in isothermal and nonisothermal conditions. Densification of the porous body occurs under action of Laplace pressure, generated by surface tension, and applied pressure. The densification kinetics of porous metals and crystalline compounds in initial and intermediate stages of sintering with static external pressure represent nonlinear steady-state creep controlled by a climb dislocation mechanism in solid matrix forming porous material. Activation energies of this mechanism are consistent with the bulk diffusion. A diffusional creep controls the pressure sintering kinetics in a later stage. The rheological models of deformable viscoelastic bodies and the associated dynamic strain theory for viscoelastic irreversibly compressible bodies, based on the energy conservation law, enable a quantitative description of their densification under dynamic loading. At the same time it is taking into account the internal energy of deformable body. The solutions of dynamic systems involve the mechanical interaction of compacting machine with this body. The simulation of impact sintering of porous metals shows that the viscosity of the matrix, that forms the porous body, and the activation energy of viscous deformation dramatically decrease with increasing initial impact velocity. This promotes the compaction of the material to practically nonporous state and enhances its mechanical properties.
Discrete Element Simulation of Machining Cracks in Brittle Materials during High Speed Cutting
Authors: He Yong , Zhang Jun , Jiang Yi Fei , Liu Hong Guang , Zhao Wan Hua
Published: January 2016

The dynamic process of cracks initiation in brittle materials during high speed cutting is primary for the analysis of material fracture mode and finished surface. Cast iron was considered in this paper and discrete element method (DEM) was employed to create a density packed bonded-particle model for studying its machining cracks. The numerical tests of split Hopkinson pressure bar (SHPB) and oblique plane impact were conducted to calibrate the dynamic behaviour of the model. The cutting simulations were carried out for a range of rake angles and cutting speeds. The results showed that both the processes of cracks initiation and the cracks distribution were different greatly under different cutting conditions and the cracks number increased with the cutting speed. In addition, within the detection zone in the model, the duration of crack initiation decreased dramatically with the increase of cutting speed in the lower range. But for the high speed cutting, the duration tended to be stable and was not affected by cutting speed and it was very close to the time of stress wave produced by cutting arriving at the zone. Furthermore, the stress state of particles’ connectors under the action of stress wave was analysed, which suggests that the stress wave is the key factor causing cracks initiation of brittle materials during high speed cutting.
Effect of Spindle Speeds on 3D Topography of Ball-End Milled Surfaces Using Wavelet Analysis Method
Authors: Liu Shuai , Zhao Jun , Qin Wen Zhen , Pang Ji Ming
Published: January 2016

Optical profiler is employed to acquire topography height data of ball-end milled die steel surface under different spindle speeds ranging from 2000rpm to 12000rpm with lead angle of 20° and tilt angle of-10°. By multi-scale wavelet analysis, measured height data are decomposed and then been reconstructed, meanwhile 3D topography and 3D roughness in different frequency bands are obtained. The results show that the changing trend of roughness with frequency band under different spindle speeds is not the same. In the high frequency bands, roughness has a tendency to increase with the increasing spindle speed. In the median frequency band, the roughness of the surface machined under low spindle speed 2000 rpm is the largest and the roughness of the surface machined under high spindle speed 12000 rpm is the lowest. In the low frequency bands, the roughness of the surface machined under low spindle speed 2000rpm is much larger than those obtained under other spindle speeds, and with the increasing spindle speed, the changing trend of roughness increases firstly then decreases.
Experimental Study on Micro Milling of Carbon Fiber Reinforced Plastics
Authors: Wu Xian , Li Liang , He Ning , Hao Xiu Qing
Published: January 2016

Recently the demands for miniature component of varying materials have been rapidly increasing in aerospace industry. Carbon fiber reinforced plastics is widely used as functional or structural material due to its superior material properties. It also is one of the difficult to machine materials because of the poor machinability. This paper presents an experimental study on micro milling of carbon fiber reinforced plastics with self-developed polycrystalline diamond tool. Cutting force and specific cutting energy are analyzed. The minimum chip thickness and carbon fiber diameter are found to have great effect on the cutting force signature peak. Tool wear mechanism of polycrystalline diamond tool also is investigated.
The Grinding and Test of Annular Milling Cutter with Double-Circular-Arc
Authors: Chen Tao , Li Xian Chuang , Wang Chang Hong , Miao Guang , Wang Yan Yan
Published: January 2016

For the problem of the non standard cutter shape cutting edge not smooth transition connection and flank face of cutting tool grinding precision difference, the influence of wheel deformation is analyzed to different grinding linear speed, and the grinding wheel deformation error compensation grinding method is studied in this work. The grinding of annular milling cutter with double-circular-arc is processed in five axis CNC tool grinder. Finally the machining precision of annular milling cutter with double-circular-arc is tested by the tool test center, the result show that the wheel grinding method based on compensation of grinding can realize smooth transition in different parts of cutting edge belt of annular milling cutter with double-circular-arc and flank grinding precision is ensured.
An Evaluation Method Based on Grey Relational Grade for Cutting Tool Performance in the Milling of Titanium Aircraft Components
Authors: Jia Yu Pei , Zhao Wei , Li Liang
Published: January 2016

Cutting tools play an important role in the cutting process of titanium aircraft components, but it is difficult to comprehensively evaluate the cutting tool performance, so the selection of appropriate cutting tool becomes extremely important. In this paper, an evaluation method using grey relational analysis for cutting tool performance was proposed. Meanwhile, in this method, a test benchmark with some typical difficult-to-machined features extracted from titanium aircraft components was designed, and the processing route was developed. Grey comprehensive evaluation models of cutting tool performance were established for the rough and finish machining respectively. Finally, the grey comprehensive evaluation models were used to evaluate the cutting tool performance in the milling experiments of the benchmarks. The results show that the grey relational comprehensive evaluation method is convenient and effective to evaluate milling tools performance for titanium aircraft components.
2D Barcode Identification Technology Application in Tool Management System for Workshop
Authors: Du Wen Ping , Li Liang , Zhao Wei
Published: January 2016

With the development of advanced automation degree industries, the requirements of network management for workshop tool become more and more urgent. A very important part in network management system is identification technology of the tool. In this paper, 2D (two-dimensional) barcode identification technology is applied in the tool information in real-time query to realize network management. The 2D barcode reading device, which is combined with the local computer decoding software, could achieve communication between production line and the server. By using 2D barcode identification technology, it could achieve network management for workshop tool, improve production efficiency and reduce the artificial error.
Experimental Analysis of Damping Fixture for Thin-Walled Workpiece Milling
Authors: Liu Dong Sheng , Luo Ming , Zhang Ding Hua
Published: January 2016

Thin-walled workpieces are widely used in the aerospace manufacturing industry in order to reduce the weight of structure and improve working efficiency. However, vibration is easy to occur in machining of thin-walled structures due to its low stiffness. Machining vibration will result in lower machining accuracy as well as machining efficiency. In order to reduce the machining vibrations of thin-wall workpieces, commonly used method is to select proper machining parameters according to the chatter stability lobes, which is generated according to the machining system parameters. However, this method requires exact system parameters to be determined, which are always changing in the machining process. In this paper, a special designed fixture with damping materials for the thin-walled workpiece is presented based on the machining vibration control theory, and analysis of the effect of vibration suppressing is obtained through the contrast of vibration tests of milling the thin-walled workpiece on the damping clamp. The damping material is used to consume vibration energy and provide support for thin-walled structure. Machining test was carried out for thin-walled structure machining to validate the effectiveness of the proposed method.
Vibration Control of HSM of Thin-Wall Titanium Alloy Components Based on Finite Element Simulation
Authors: Zhao Kang , Su Hong Hua , He Lin Jiang , Liu Ying Zhi
Published: January 2016

During high-speed machining, the vibration will result in poor workpiece surface and damage the cutting tool as well as the machine tool. It will limit the productivity and lower the quality of thin-wall titanium alloy components. Moreover, vibration occurrence is strongly affected by the dynamic response of the whole system, particularly the stiffness of workpiece-fixture system. Improper fixture layout is prone to generate vibration, especially for the flexible workpiece. Hence, it’s necessary to suppress the vibration and improve the fixture design. In this work, a finite element model of the workpiece-fixture system is built. Based on this model, the laws of the natural frequency and vibration modals under different fixturing methods are obtained, which can be used to refine fixture design. With several additional auxiliary supports, the stiffness of the workpiece-fixture system is improved and the result showed that, the natural frequencies of thin-wall titanium alloy components can be improved to a level which is too high to be reached by tool’s excitation. The result of this study is helpful to design the optimum fixture scheme of thin-wall titanium alloy components.
Growth Time Optimization of Fine Grained Diamond Coated Drills for Machining CFRP
Authors: Wang Xin Chang , Shen Xiao Tian , Zhao Tian Qi , Sun Fang Hong , Shen Bin
Published: January 2016

Carbon fiber reinforced plastics (CFRP), which are widely used in the aerospace and some other new-tech industries, are considered very difficult to machine due to the material anisotropic and inhomogeneous features. Chemical vapor deposition (CVD) diamond films are suitable as protective coatings on cutting tools for machining advanced composite materials, owing to their extremely high hardness, favorable wear resistance, low friction coefficient and high thermal conductivity. Among different types of diamond films, the fine grained diamond (FGD) film can provide much more favorable environment for machining CFRP due to the small grain size, low surface roughness and the retentivity for the sharpness of the cutting edge. In the present study, aiming at drilling CFRP, FGD films of different thicknesses are deposited on Φ3 mm drills by controlling the growth time, adopting the common-used hot filament CVD (HFCVD) technology. It can be directly proved by deposition experiments that overlong growth time can induce spontaneous film delamination and removal before the cooling stage, probably as a result of the excessive residual stress concentrated on the complicated surfaces. As demonstrated by the cutting tests, with increasing the growth time, the main failure mode of the FGD coated drill changes from film delamination to flank wear/tipping to film delamination, and the maximum tool life exists when the growth time is moderate, because the flimsy film cannot provide sufficient protective effects on the film-substrate interface and even hasn’t totally cover the substrate, while there’s relatively higher residual stress in the film that is too thick, and such the residual stress can significantly deteriorate the film-substrate adhesion. Moreover, during the life cycle of each FGD film, relatively shorter growth time often means the slightly better hole quality, attributed to the retentivity of the initial shape of the uncoated drill that is optimal designed for machining CFRP, especially the weaker passivation of the cutting edge.
Simulation of Tool Wear in Prestressed Cutting Superalloys
Authors: Peng Rui Tao , Li Jing , Tang Xin Zi , Zhou Zhuan
Published: January 2016

In high speed machining superalloys processes, tool wear is strongly influenced by the cutting temperature and contact stresses. Finite element analysis of machining can be used as a supplementary to the physical experiment, this paper provides investigations in 2D and 3D finite element modeling and simulation of prestressed cutting for GH4169 superalloy, a tool wear model for the specified tool and workpiece pair is developed based on the Usui's wear model, furthermore, tool temperature, wear rate and nodal displacement on the face of tool in prestressed cutting of superalloy is analyzed under various prestress condition and cutting parameters, and Python language is adopted to modify the Abaqus code used to allow tool wear calculation and tool geometry updating. The results of the simulation indicate that the tool wear rate increases with the increase of cutting time, and the influence of the prestress to tool wear in prestressed cutting process of shaft part is unremarkable.
Kinematical Smoothing of Rotary Axis near Singularity Point
Authors: Grandguillaume Laureen , Lavernhe Sylvain , Tournier Christophe
Published: January 2016

This paper deals with singular configurations of a 5-axis machine tool in high speed milling which may lead to the appearance of large incoherent movements of rotary axes near singularity points. These movements generate slowdowns of the actual feedrate during the execution of the tool path, which affect quality and productivity. Thus, this paper proposes a method to detect these behaviors during machining simulation and correct the tool path. Unlike the literature methods, this correction consists in modifying the tool axis orientation by going through the singularity point while respecting maximum velocity, acceleration and jerk of the rotary axis. For that purpose, the initial articular positions of the rotary axis near the singularity point are fitted with B-spline curves, modified and finally discretized for linear interpolation. Experimental investigations on a test part are carried out to show the efficiency of the method.
Grain Refinement and Thermal Stability of AISI1020 Strips Prepared by Large Strain Extrusion Machining
Authors: Zhang Jia Yang , Li Bing Lin , Zou Zhi Jie , Zou Tong , Deng Wen Jun
Published: January 2016

Low carbon steel (AISI1020) strips with grain refinement were successfully produced by large strain extrusion machining (LSEM).A finite element simulation was performed to make comprehensible the deformation behavior of LSEM process. The influence of annealing temperature and annealing time on the microstructure and mechanical properties of strips was investigated by two sets of heat treatments and Vickers hardness test. As a result, strips can maintain high hardness under 400°C but start losing it as the temperature increased to 500°C and above. When annealED at 300°C for 1~9h, hardness of strips can maintain at almost the same level as that before annealing. Obvious hardening was found when annealing at 200~300°C mainly because of the dislocations atresia. Despite of the anneal-hardening behavior, these results indicated that the extruded AISI1020 strip has a good thermal stability at temperature below 400°C.
Experimental Study on Cutting Force and Cutting Power in High Feed Milling of Ti5Al5Mo5VCrFe
Authors: Sun Hui , Xiao Hu , Li Liang
Published: January 2016

In order to improve the rough machining efficiency of titanium alloy, experiments were carried out to investigate the influence of feed per tooth on cutting force and cutting power with index-able coated carbide inserts. The curves of cutting parameters, including cutting force and cutting power, were obtained by single factor test. The results showed that, as the feed per tooth increases, the cutting force increases, especially in the direction of cutting width. All forces almost changed linearly with the changing of feed, and the cutting force of feed direction was the smallest force among the three directions of cutting force. The analytical model of tangential cutting force in the x-y plane was established. By calculating average chip thickness and relationships between tangential cutting force and measurements of cutting force to predict the cutting power, the calculation results were accurate which compared with the actual output power of the machine tool.
A Common Genetic Variant in TLR1 Enhances Human Neutrophil Priming and Impacts Length of Intensive Care Stay in Pediatric Sepsis
Authors: Whitmore Laura C. , Hook Jessica S. , Philiph Amanda R. , Hilkin Brieanna M. , Bing Xinyu , Ahn Chul , Wong Hector R. , Ferguson Polly J. , Moreland Jessica G.
Published: January 2016

Polymorphonuclear leukocytes (PMN) achieve an intermediate or primed state of activation following stimulation with certain agonists. Primed PMN have enhanced responsiveness to subsequent stimuli, which can be beneficial in eliminating microbes but may cause host tissue damage in certain disease contexts, including sepsis. As PMN priming by TLR4 agonists is well described, we hypothesized that ligation of TLR2/1 or TLR2/6 would prime PMN. Surprisingly, PMN from only a subset of donors were primed in response to the TLR2/1 agonist, Pam3CSK4, although PMN from all donors were primed by the TLR2/6 agonist, FSL-1. Priming responses included generation of intracellular and extracellular reactive oxygen species, MAPK phosphorylation, integrin activation, secondary granule exocytosis, and cytokine secretion. Genotyping studies revealed that PMN responsiveness to Pam3CSK4 was enhanced by a common single-nucleotide polymorphism (SNP) in TLR1 (rs5743618). Notably, PMN from donors with the SNP had higher surface levels of TLR1 and were demonstrated to have enhanced association of TLR1 with the endoplasmic reticulum chaperone gp96. We analyzed TLR1 genotypes in a pediatric sepsis database and found that patients with sepsis or septic shock who had a positive blood culture and were homozygous for the SNP associated with neutrophil priming had prolonged pediatric intensive care unit length of stay. We conclude that this TLR1 SNP leads to excessive PMN priming in response to cell stimulation. Based on our finding that septic children with this SNP had longer pediatric intensive care unit stays, we speculate that this SNP results in hyperinflammation in diseases such as sepsis.
Molecular Mechanisms of Airway Hyperresponsiveness in a Murine Model of Steroid-Resistant Airway Inflammation
Authors: Manni Michelle L. , Mandalapu Sivanarayana , McHugh Kevin J. , Elloso M. Merle , Dudas Paul L. , Alcorn John F.
Published: January 2016

IL-13 and IL-17A, produced mainly by Th2 and Th17 cells, respectively, have an influential role in asthma pathogenesis. We examined the role of IL-13 and IL-17A in mediating airway hyperresponsiveness (AHR), lung inflammation, and mucus metaplasia in a dual Th2/Th17 model of asthma. IL-13 and/or IL-17A were neutralized using mAbs. Th2/Th17 adoptive transfer induced a mixed asthma phenotype characterized by elevated eosinophilia and neutrophilia, tissue inflammation, mucus metaplasia, and AHR that were partially reversible with steroid treatment. Pulmonary inflammation and quasi-static lung compliance were largely unaffected by neutralization of IL-13 and/or IL-17A. However, neutralization of IL-13 alone or in combination with IL-17A significantly attenuated AHR and mucus metaplasia. Further, STAT6 activation was attenuated following IL-13 and IL-13/IL-17A Ab treatment. We next assessed the role of STAT6 in Th2/Th17-mediated allergic airway disease using STAT6−/− mice. STAT6−/− mice adoptively transferred with Th2/Th17 cells had decreased AHR compared with controls. These data suggest that IL-13 drives AHR and mucus metaplasia in a STAT6-dependent manner, without directly contributing to airway or tissue inflammation. IL-17A independently contributes to AHR, but it only partially mediates inflammation and mucus metaplasia in a mixed Th2/Th17 model of steroid-resistant asthma.