Track Recording Research Articles

Track deflection and stiffness measurements from a track recording car

A new innovative method for track deflection and track stiffness measurement is described and used on the iron-ore line in Sweden. The method uses two different measurement systems of longitudinal level on one axle, and by comparing them in a new way it is possible to extract the unloaded level and the effect of the loading from the loaded longitudinal level. Displacement due to loading can also be interpreted as a track stiffness value if the wheel load is simulated or measured. With this method, a new approach to condition monitoring of track is created due to the possibility of monitoring stiffness and longitudinal level at the same time using a track recording car. The method has been used in an extensive measurement campaign on the iron-ore line in the north of Sweden. Many examples are given in this paper to illustrate different track defects on ordinary track, mainly on track section (bandel) 118. Hanging sleepers and mud-pumping places have been successfully located using the new method. The method has been used in both winter and summer conditions. We have found that the track stiffness/deflection level does not vary considerably with change of season. This result is explained by the design decision in the 1980s to use soft fastener pads, which seems to have been a very good decision.

방향틀림이 KTX 주행거동에 미치는 영향 분석

궤도틀림은 철도차량의 주행안전성 및 승차감에 매우 큰 영향을 미치는 중요 인자 중 하나이다. 따라서, 차량의 주행안전성과 승차감의 확보를 위해서는 주행속도, 차량의 동적특성, 궤도틀림 검측차의 검측특성, 검측주기등을 고려하여 적정한 궤도틀림 기준을 설정하고, 관련 기준에 따라 궤도틀림을 철저히 관리하여야 한다. 본 논문에서는 궤도틀림 중에서 방향틀림이 KTX 차량의 거동에 미치는 영향을 조사하기 위하여 철도차량 동특성 해석프로그램인 VAMPIRE를 이용하여 방향틀림의 파장과 진폭에 대한 매개변수해석을 수행하였다. 방향틀림 크기와 파장에 따른 KTX의 탈선계수, 대차가속도, 차체가속도 및 궤도횡압 등의 주행거동을 조사하였으며, 방향틀림이 KTX차량의 주행안전성과 승차감에 미치는 영향을 분석하였다. 방향틀림은 차량주행안전성에 미치는 영향이 크며, KTX 주행안전성 확보를 위하여 방향틀림을 엄격하게 관리하여야 함을 알 수 있었다. Track irregularities is one of the key factors influencing the running behavior of trains. In order to ensure safety and ride comfort of train, the criteria for track irregularities should be adequately established regarding vehicle velocity, vehicle characteristics, characteristics of the track recording car, and measurement interval. Also, track maintenance should be carried out thoroughly according to the criteria for managing track irregularities. Numerical analysis was conducted to investigate the influence of track alignment on the running behavior of Korean high speed train(KTX). Various wavelengths and amplitudes of lateral alignment were considered as parameters for this study using the Vampire program, a vehicle dynamics modeling package in railway environment. Derailment, lateral load, bogie acceleration and body acceleration of numerical analysis results due to alignment were investigated. Finally, the influence of the alignment on safety and ride comfort for the KTX was evaluated. This study indicates that alignment irregularities have significant impacts on running safety, and that the criteria used to manage alignment irregularities should be restrictive to ensure the running safety of the KTX.

Robust Repetitive Perfect Tracking Control of HDDs Based on Re-learning Scheme

This paper presents an improved method of a repetitive controller based on perfect tracking control (PTC) in order to reject the variable repeatable runout (RRO) of hard disk drives (HDDs). The author's group proposed repetitive PTC (RPTC) with a switching mechanism. RPTC is realized by using periodic a signal generator (PSG) and PTC. The PSG produces a feedforward signal from the periodic disturbance, and the PTC generates a control input to cancel the periodic error in the steady state. However, we have not considered the difference between the RROs of tracks. This paper proposes a re-learning scheme by taking into account the correlation of adjacent tracks. Finally, the advantages of RPTC using the proposed scheme are demonstrated through simulations and experiments using a hard disk drive equipment with discrete track recording media (DTR). Head-positioning controllers of hard disk drives (HDDs) are generally composed of two control modes: the track- seeking mode and the track-following mode. High-speed po- sitioning and small residual vibration are important in the track-seeking mode, and the disturbance rejection perfor- mance is important in the track-following mode. Digital two-degree-of-freedom controllers generally have two samplers for the reference signal r(t) and the output y(t), and one holder on the input u(t). Therefore, there exist three time periodsTr, Ty ,a ndTu which represent the sampling time of r(t), y(t), and u(t), respectively. In the case of HDDs, the position error is detected by the discrete servo signals em- bedded in the disks. Therefore, the output sampling period Ty is decided by the number of these signals and the rotation frequency of the spindle motor. However, it is possible to set the control period Tu shorter than Ty because of the recent de- velopment of microprocessor. Thus, the servo system can be regarded as a multirate control system where Tu ≤ Ty. Then, many multirate controllers have been proposed both for the track-seeking mode and the track-following mode (1)-(3) . Recently, magnetic printing media, discrete track record- ing media (DTR) and pre-formatted media with perpendicu- lar anisotropy are studied for high track density as new gen- eration media (4) . These new generation media can record servo information in the manufacturing process of disks al- though the conventional disk uses servo track writers after disks are installed in drives. This improved technology can provide high recording density compared with conventional disks. However, it is known that the servo information of these pre-formatted media generally has large decentering from the rotating center. Therefore, higher track-following

Thickness alterations of CR-39 plastic detectors due to the heating influence: Basic theory and experimental results

Heating experiments were conducted on CR-39 polymer/plastic detector samples at temperatures between 50 and 175 °C for various time intervals from 5 to 210 min to investigate the thermal behavior of detector material. Mass and thickness of un-heated and heated polymer samples were measured. Three distinct regimes have been observed showing different degrees of changes in thickness and mass of annealed samples. The percent change of thickness was considerably higher than the mass change during heating. Thermodynamic concepts are used to explain the experimentally observed heating regimes. Role of the difference between free energies of lateral and fold surfaces in detector thickening during heating is discussed. Scanning electron microscopy (SEM) was carried out on un-heated and heated CR-39 samples to examine the surface alterations due to heating. Results are useful for researchers who employ track detectors for radiation measurements in nuclear reactors and cosmic rays. They are also interesting for researchers in related fields, like fission track dating, which consider the thermal history of track recording materials. Our quantitative data and SEM imaging suggests that structural changes, especially surface changes in CR-39 polymer are very important and need to be explored carefully through joint SEM and the Atomic Force Microscopy (AFM).

Development of track condition assessment model based on visual inspection

Inspection and evaluation of railway track conditions are usually accomplished by analysis of geometric data obtained from track recording cars. Although most geometric deviations can be recorded by these cars, track structural defects cannot be identified during automated inspections and the causes of track problems cannot be fully recognised. This limitation makes the efficiency of current maintenance approaches questionable. This research proposes a new method of track evaluation based on the observation of track structural defects. Dominant observable structural distresses were studied and a methodology was proposed to translate structural problems into a meaningful numerical rating. The contribution of a track structural defect to track quality was investigated and a track structural quality index model was developed. This index is a function of the severity and density of distress types. To examine the practicability and applicability of the new index, a practical use of the model is presented.

Intertrack Interference Mitigation on Staggered Bit-Patterned Media

One of the possible island distributions being considered for bit-patterned magnetic recording is a hexagonal array, leading to what is called staggered bit-patterned media. In this paper, we investigate the equalization techniques and bit error rate (BER) performance for two different recording methods on staggered media-namely, one array per track or single-track staggered media and two arrays per track or double-track staggered media. With single-track equalization, recording a track on two arrays may reduce intertrack interference (ITI) and outperform the single array per track recording. However, a new multitrack detection technique proposed recently can substantially mitigate ITI and dramatically change the BER performance of the two recording methods. Our investigation shows that by using this technique, the single-track staggered media can have better BER performance than double-track staggered media, even at very high areal densities.

Comparative Fitness of Irradiated Light Brown Apple Moths (Lepidoptera: Tortricidae) in a Wind Tunnel, Hedgerow, and Vineyard

Light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is the target of the sterile insect technique, but reduced moth fitness from irradiation lowers the effective overflooding ratio of sterile to wild moths. New measures of insect quality are being sought to improve field performance of irradiated insects, thus improving the cost effectiveness of this technique. Male pupae were irradiated at intervals between 0 and 300 Gy, and adult flight success was assessed in a wind tunnel equipped with flight track recording software. A dose response was evident with reduced successful search behaviors at higher irradiation doses. Irradiation at 250 Gy reduced arrival success to 49% of untreated controls, during 2-min assays. Mark-release-recapture of males irradiated at 250 Gy indicated reduced male moth recapture in hedgerows (75% of control values of 7.22% +/- 1.20 [SEM] males recaptured) and in vineyards (78% of control values 10.5% +/- 1.66% [SEM] recaptured). Males dispersed similar distances in both habitats, and overflooding ratios dropped off rapidly from the release point in both landscapes. Transects of traps with central releases proved to be an efficient method for measuring the quality of released males. Relative field performance of moths was greater than suggested by wind tunnel performance, which could be due to time differences between the two assays, two-minute wind tunnel tests compared with days in the field treatments. Release strategies involving ground releases should consider the effect of limited postrelease dispersal. Aerial release could solve this problem and warrants investigation.

The Study of Moving Images Track Recording System which Based on Mean Shift Algorithm

Intelligent tracking system based on video recording problem is a key technique in computer vision and research focus, a lot of engineering applications and video tracking technology has a close relationship. This system is a development platform for the ADSP-BF533 core, together with the VisualDSP + + integrated development and debugging environment, implementation, and optimization MeanShift tracking algorithm to achieve real-time tracking of moving target shooting can be used in sporting events, intelligent monitoring. Test data show that the system can control the PTZ camera tracking rigid and non rigid shooting targeting.

Magnetic properties and recording performances of patterned media fabricated by nitrogen ion implantation

Nitrogen ion implantation was performed on CoCrPt–SiO2 perpendicular media with a resist mask to fabricate patterned media. Signal amplitude and autocorrelation signal-to-noise ratio of the preamble pattern were measured to evaluate the quality of the pattern fabricated by the ion implantation. The signal-to-noise ratio and the jitter were closely related to the saturation magnetization of the ion-implanted area. The remained magnetization of the ion-implanted area probably affects edge roughness of the magnetic pattern. Larger reduction of the saturation magnetization at the ion-implanted area is important for obtaining higher signal quality. Off-track profiles and 747 curves were measured for 76-nm-pitch discrete track fabricated by ion implantation. The results show that discrete track recording had advantages over recording on continuous magnetic film, which indicates that the fabricated patterns were successfully isolated. The nitrogen ion implantation was effective in fabricating isolated magnetic tracks or isolated magnetic dots for the patterned media.

Numerical Solution of the Boltzmann Based Lubrication Equation for the Air-Bearing Interface Between a Skewed Slider and a Disk With Discrete Data Tracks

Discrete track recording (DTR) is a method for increasing the recording density of a data storage disk by use of a pattern arrangement of discrete tracks. The DTR track structure consists of a pattern of very narrow concentric raised areas and recessed areas underneath a magnetic recording layer. In order to design the air-bearing slider platform that houses the magnetic transducer for DTR application at very low fly heights, the influence of the disk surface topography as a surface roughness effect must be taken into account. This paper is focused on the numerical solution of the roughness averaged lubrication equation reported recently in the work of White (2010, “A Gas Lubrication Equation for High Knudsen Number Flows and Striated Rough Surfaces,” ASME J. Tribol., 132, p. 021701) and is specialized for the influence of discrete disk data tracks on the recording head slider-disk air-bearing interface subject to a nonzero skew angle formed between the slider longitudinal axis and the direction of disk motion. The generalized lubrication equation for a smooth surface bearing and appropriate for high Knudsen number analysis is quite nonlinear. And including the averaging process required for treatment of a nonsmooth disk surface, as well as the rotational transformation required to allow for a nonzero skew angle, increases further the nonlinearity and general complexity of the lubrication equation. Emphasis is placed on development of a numerical algorithm that is fast, accurate, and robust for air-bearing analysis of complex slider surfaces. The numerical solution procedure developed utilizes a time integration of the lubrication equation for both steady-state and dynamic analyses. The factored-implicit scheme, a form of the more general alternating-direction-implicit numerical approach, was chosen to deal with the two-dimensional and highly nonlinear aspects of the problem. Factoring produces tightly banded coefficient matrices and results in an algorithm that is second-order accurate in time while requiring only the solution of tridiagonal systems of linear equations in advancing the computation from one time level to the next. Numerical solutions are presented that demonstrate the performance of the computational scheme and illustrate the influence of some discrete track parameters on skewed air-bearing performance as compared with a flat surface data storage disk.

Surface-micromachined thermoelectric infrared focal-plane array with high detectivity for room temperature operation

Thermopile detectors are particularly well suited for spectral imaging, space science applications, track recording, presence detection and applications with low energy consumption. The purpose of this work is the fabrication of a surface-micromachined 2-D high detectivity thermopile array using a highly effective BiSb/Sb thermocouple materials combination. The thermoelectric array is built on 8×8 pixels with an active area of 100μm in square, which are wired directly. Thermopile structure and absorber area are manufactured upon a sacrificial layer based on polyimide, which is removed at the end of the manufacturing process. Thermoelectric layers as well as wiring layers has been patterned almost exclusively by lift-off technique in order to obtain very small structure dimension with high reliability as well as high integration level. The active area of detectors can be equipped with two absorber types for different application, a broadband colloidal silver black layer as well as a quarter wavelength arrangement for the MIR wavelength range from 8 to 14μm. The detectivity of so manufactured FPAs is about 1×109 Jones exceeding most of the state-of-the-art thermopile detectors.

Investigation of contact deformation and wear characteristics of discrete track recording media

The contact deformation and wear characteristics of smooth and discrete track recording (DTR) media are investigated using nano-indentation and nano-scratch testing. Plastic deformation of the land areas between adjacent grooves was found to be substantially larger than in the smooth regions of the same disk. Reciprocating wear tests showed that wear was more severe for discrete track disks than for smooth disks. To improve the tribology of DTR media, planarization of discrete track disks appears to be necessary.

Space flight affects motility and cytoskeletal structures in human monocyte cell line J‐111

Certain functions of immune cells in returning astronauts are known to be altered. A dramatic depression of the mitogenic in vitro activation of human lymphocytes was observed in low gravity. T-cell activation requires the interaction of different type of immune cells as T-lymphocytes and monocytes. Cell motility based on a continuous rearrangement of the cytoskeletal network within the cell is essential for cell-cell contacts. In this investigation on the International Space Station we studied the influence of low gravity on different cytoskeletal structures in adherent monocytes and their ability to migrate. J-111 monocytes were incubated on a colloid gold substrate attached to a cover slide. Migrating cells removed the colloid gold, leaving a track recording cell motility. A severe reduction of the motility of J-111 cells was found in low gravity compared to 1g in-flight and ground controls. Cell shape appeared more contracted, whereas the control cells showed the typical morphology of migrating monocytes, i.e., elongated and with pseudopodia. A qualitative and quantitative analysis of the structures of F-actin, β-tubulin and vinculin revealed that exposure of J-111 cells to low gravity affected the distribution of the different filaments and significantly reduced the fluorescence intensity of F-actin fibers. Cell motility relies on an intact structure of different cytoskeletal elements. The highly reduced motility of monocytes in low gravity must be attributed to the observed severe disruption of the cytoskeletal structures and may be one of the reasons for the dramatic depression of the in vitro activation of human lymphocytes.

A Billiards Track and Score Recording System by RFID Trigger

Billiards is a interesting game, which has been played for hundreds of years in some form. In tradition, the billiards game uses manual scoring that could neither record automatically as balls are hit into pocket nor provide backend analysis. Therefore, Our research use RFID component combined with Internet and Webcam by UML object-based analysis technologies, implemented a Billiards track and score recording system that has the characteristics of instant recording in the game,and it can understand about the contestant begin the game,or analysis athlete training by coach after the game.

Marathon Monitoring and Safety using Ad Hoc Networks

This paper proposes the use of modern communication technology that sports can be different, especially, in competition, which they are difficult to track (recording) because the rules of the competition and distance cause the effects of time recording errors in terms of accuracy and impartiality. The integrated vehicular ad hoc network (VANET) is recommended to accommodate such problems. The system is integrated by a 3G or 4G cellular wireless network. By using the general packet radio service (GPRS) to monitor closely to the athletes though the route and duration of competition, where the sports safety and clarity can also be monitored and realized.

Effect of Transition Curvature and Track Edge Fluctuation on Track Edge Noise for Narrow Track Recording

We investigated the effect of track edge noise on transition curvature and track edge fluctuation through experiments and calculations. We measured and calculated two types of recording heads that had similar magnetic write widths, but different transition curvatures. In both the measurements and calculations, track edge noise increased more at high linear density with head with larger transition curvature. This was due to wider erase band, which is considered to be noise source at the track edge. We also clarified that reducing the transition curvature and track edge fluctuation was effective to improve bit error rate, because reducing the transition curvature increases signal-to-noise ratio (SNR), especially at high linear density, and reducing the track edge fluctuation also increases SNR, especially at low linear density. Therefore, reducing both transition curvature and track edge fluctuation is necessary in order to reduce the track edge noise and consequently achieve high areal density.

Channel Modeling and Capacity Bounds for Two-Dimensional Magnetic Recording

Two-dimensional magnetic recording (TDMR) differs from traditional track recording in that the bit-size-to-grain-size ratio is drastically reduced so that the channel bits are roughly of the same sizes as those of the magnetic media grains. This is envisioned to be achieved by shingled writing, a write-process in which the corner-writer partially overwrites the previously written adjacent track, effectively writing very closely spaced narrow tracks with no guard bands. Since the tracks are very narrow, they can be read by an array of read-elements whose spacing is equal to the narrow track pitch, creating a two-dimensional (2-D) array of readback signals (the two dimensions being the cross-track and the down-track dimensions). In the absence of an array of read elements, the same 2-D readback can be obtained by progressive scans of a single read element that reads one narrow track at a time and stores the readback signal in a 2-D array. In this paper, we present simple magnetic grain media models and shingled-write process models that capture the essence of TDMR. We assume that the granular recording medium consists of randomly shaped tiles (each tile represents a grain), randomly covering the medium plane. We then derive a suitable 2-D read/write process model. Using proper information-theoretic inequalities and bounding techniques, we derive methods to bound the capacities of TDMR channels. The results reveal that information capacities in excess of 0.6 user bits per grain are possible to attain over TDMR channels.

Optical Design Challenges of Thermally Assisted Magnetic Recording Heads

We developed three home-made modeling programs to design thermally assisted magnetic recording heads: optical beam propagation method for waveguides, optical finite difference time domain method for plasmon generators, and thermal/micromagnetic finite difference method for the recording media. These models lead to the following results. To get higher throughput efficiency of the waveguide, the periodic wavy thickness of the inlet can provide better inlet coupling with laser diode light, and the wavy taper shape can improve the propagation efficiency. As for plasmon generators, the model requires waveguide, recording media and main-pole to estimate the correct performance, because the optimized design depends on all of these parts. Our proposed sharp pointed plasmon generator can provide tiny near field spot, and it must have good scalability for narrow track recording. In addition to these optics models, we performed recording process simulation. As a result, depending on the condition of the thermal spot and head field alignment, either thermal or magnetic field can be dominant in creating the final magnetic transition in the media. The signal to noise ratio and the transition curvature are greatly affected by the recording process.

Effect of dipole interaction on microwave assisted magnetization switching

Microwave assisted switching (MAS) of magnetization has attracted much attention as an alternative technique for future ultrahigh density magnetic recording. In this study, to elucidate the effect of magnetostatic interparticle interaction on MAS, we have calculated the switching behavior for a row of three uniaxial magnetic particles as a simplest case. When a dc field is applied only to one particle of the row in an ac field, MAS selectively occurs in the particle and not in the neighboring particles. This behavior may be very effective to realize narrow track recording without adjacent track erasure problem by downsizing a dc field source below an ac source. It has been also found that when both ac and dc fields are applied to all the particles, coherent magnetization precession is cooperatively induced in all the particles due to dipole-dipole interaction among neighboring particles, resulting in significant reduction of the switching field. This coherent magnetization precession is not only effective to reduce the switching field but also to suppress the effect of magnetic anisotropy dispersion, suggesting the effectiveness of MAS in granular recording media.

Effect of Transition Curvature on Signal Quality for Narrow Track Recording

Effect of Transition Curvature on Signal Quality for Narrow Track Recording