bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of Solid Oxide Fuel Cell With La and Cr Co-Doped SrTiO3 as Anode
Authors: Yi Fenyun , Chen Hongyu , Li He
Published: December 2013

The La0.3Sr0.55Ti0.9Cr0.1O3-δ (LSTC10) anode material was synthesized by citric acid-nitrate process. The yttria-stabilized zirconia (YSZ) electrolyte-supported cell was fabricated by screen printing method using LSTC10 as anode and (La0.75Sr0.25)0.95MnO3-δ (LSM) as cathode. The electrochemical performance of cell was tested by using dry hydrogen as fuel and air as oxidant in the temperature range of 800–900 °C. At 900 °C, the open circuit voltage (OCV) and the maximum power density of cell are 1.08 V and 13.0 mW·cm−2, respectively. The microstructures of cell after performance testing were investigated by scanning electron microscope (SEM). The results show that the anode and cathode films are porous and closely attached to the YSZ electrolyte. LSTC10 is believed to be a kind of potential solid oxide fuel cell (SOFC) anode material.
Enhancement of Hard Disk Drive Performance by Using Thin Titanium Foil Disk Substrates
Authors: Nigam Anil , White James
Published: December 2013

In this paper an experimental study is reported to reduce the rotating inertia in a 2½″ HDD by replacing thick hard disk platters with thin, CP (commercially pure) titanium substrates in the range of 25 microns to 152 microns in thickness. The results of this work can be extended to other disk form factors [1]. The low inertia and thinness of the titanium foil platter can be exploited to allow disk drive products to be powered on/off rapidly, decreasing energy consumption. In addition, significantly faster rpms and data thru-put can be achieved. Also, many more disk platters can be housed in each unit, increasing storage capacity; while slimmer products that operate with low voltage battery power can be developed.
Multi-Body Modeling Effects on the Head-Disk Interface During Operational Shocks in Hard Disk Drives
Authors: Li Liping , Bogy David B.
Published: December 2013

Over the past decade, there has been an increase in the demand of hard disk drives (HDD) used in portable devices. In such applications HDDs are often subjected to mechanical shocks. Hence it is important to study the stability of mobile drives during operational shocks (op-shock) in order to improve their shock performance. Former numerical investigations [1–3] used either detailed structure models and simplified air bearing models or vice versa to understand the HDI response during an opshock event. In 2012, Rai and Bogy [4] proposed a method in which both the HDD components and the air bearing were modeled in detail and were coupled with each other. However, in this model the head actuator assembly (HAA) was assumed to be amounted on a fixed support and hence the flexibility of the base plate and those effects on the HAA were neglected. In this study, we model the HAA as mounted on the base plate to investigate the effects of HDD components on the shock performance of mobile drives.
Mapping of the Upper Limb Movements and Onset Detection
Authors: Vasquez Alejandra Avila , Chang Jen-Yuan (James)
Published: December 2013

Electromyogram (EMG) consists on the recording and measurement of the electrical potential generated by the activation of muscle fibers [1]. Electromyographic signals (EMGs) are directly linked to the movement performed by a person. Thus, the study of EMGs for the control prosthesis and exoskeletons has become increasingly popular in the past years. To provide a real time control of a prosthesis or exoskeleton (assistive device) to the user, the time between the movement performed by a healthy arm and the movement of the exoskeleton should be small as possible. The main objective of this paper is to map different movements of the upper limb. Moreover, detect the onset of the EMGs to determine which muscle is producing movement. Surface electrodes were used to perform the experiments in order to insure the comfort of the subjects. The analysis of the signal to detect the onset was done using Matlab. After mapping eight movements, results show that the EMGs recorded from the Trapezius muscle can be used as a discriminative to differentiate between movements performed by the arm and movements performed by the forearm and hand. This will reduce the time and number of EMG channels needed to correctly identify the movement performed by the upper limb of a subject.
The Effect of Contact Conditions on Demagnetization During Light Sliding Contact
Authors: Liu Yuliang , He Jun , He Jun , Bogy David B. , Zhang Guangyu
Published: December 2013

In order for the data areal recording density in the hard disk drive (HDD) to be further increased, the spacing between slider and disk must continue to be decreased. Some light sliding contact is unavoidable, and eventually it could result in the demagnetization of data stored in the HDD.
Effects of Varied Physical Mechanisms on the Evolution of Lubricant Interface During Heat-Assisted Magnetic Recording
Authors: Rajasekharan Ajaykumar
Published: December 2013

A concoction of various forces and physical effects (both mechanical and chemical) come into play in the depletion and evolution of the lubricant on the media during a heat-assisted magnetic recording (HAMR) process. They include the air-bearing shear and pressure, capillary pressure, thermo-capillary stress, disjoining pressure, lubricant desorption and the vapor recoil mechanism. The effects of these mechanisms and their complex interplay to stabilize/destabilize the lubricant interface is studied here numerically. Results for Z-type perfluropolyether (PFPE) lubricants with different polydispersity indices (PDI) are summarized.
Impact of Pattern Media Topography on the Tribology of Head-Disk Interfaces
Authors: Mate C. Mathew , Liu Z. , Kercher D. , Ruiz O. , Rubin K. , Bogdanov A. , Lille J. , Wu T.-W. , Albrecht T. R. , Marchon B.
Published: December 2013

Bit patterned media (BPM) is being pursued by the disk drive industry as a way of extending magnetic recording densities beyond 1 Tbits/in2 [1]. As the patterned topography of an unplanarized BPM disk generates a tribology quite different than smooth, continuous media, it is important to assess how this topography will impact the tribology of head-disk interfaces (HDI). In this paper, we quantify the impact of BPM topography on flying height modulation.
Dynamics of Reader Head Suspension on a Magnetic Scale With Grooves
Authors: Xu Zhi-Hao , Hsiao Heng-Sheng , Sung Cheng-Kuo , Chang Jen-Yuan (James)
Published: December 2013

In machine tool industry, the current trend is to use magnetic scales instead of mechanical scales or optical scales for linear position identification and control. As the demand for more accurate precision in magnetic scale, more stable reading head suspension is thought. Magnetic media with grooves, such as patterned-media, are considered to achieve ultrahigh magnetic pitch density. Patterned-media consists of land parts for magnetized N pole and grooves parts for S pole. The higher magnetic pitch density on the media, the lower magnetic flux we can measure. In order to measure reliable magnetic flux signal, the distance between the media and reader head needs to be as close as possible. During the process, aerodynamics, which caused by the reader head passing through groove parts with tiny distance between reader head and media, have an impact on reader head suspension which leads to vibration and misjudgment of measured signals. In this paper, parameter studies are conducted with the goal placed on correlating response of certain suspension vibration modes to optimal parameters in reader head suspension design.
Slot Misalignment Measurement for Archive Data Storage Using Dual Sensing Method
Authors: Lim Sung-Yong , Yang Hyunseok , Yoo SeungHon , Lee Han Baek , Choi Young Do
Published: December 2013

Disc cartridge for archive data storage is made up of multi slots array and each slot keeping a disc. However, misalignment between slot and disc is caused by various disturbances sources. The archive data storage should be operated stably, able to cope with the misalignment. Because, misalignment can cause disc crash against slot walls, and miss positioning between transfer robot and disc slot. Therefore, proper detecting misalignment method should be adopted in archive data storage. In this paper, analyze allowable misalignment and propose dual sensing method based on vision system. Suggested method can simultaneously detect the upper and lower part of slots using only one detector. Each image is split by changing each optical path intentionally through lens shifting of 4f imaging system.
Friction Induced Lateral Vibrations of a Tape Moving in Contact With a Slewing Head
Authors: Yang Hankang , Müftü Sinan
Published: December 2013

In dynamic systems, motion transfer due to frictional effects could result in quasi-harmonic oscillations and stick-slip, with potentially undesirable effects. The track-following motion of a read/write (RW) head-assembly transfers frictional forced onto the translating tape. This, in turn, has the potential to introduce unwanted dynamic motion into the system, and to affect the track following operation. In extreme cases the tape could stick onto the head-assembly, which could then create the potential for sudden release (slip) of the tape, if the restoring forces exceed the static friction forces. Due to longitudinal tape motion, stick is only a possibility during start-stop operations. However, with increasingly smoother tape, the effects of friction induced vibration (FrIV) could become problematic for the next generation of tape drives.
Identification of Critical Resonant Modes Above the Nyquist Frequency Using Multirate Inputs
Authors: Yan Weili , Du Chunling , Pang Chee Khiang
Published: December 2013

A mechanical structure embedded in a sampled-data system often contains several resonant modes above the Nyquist frequency of the system output’s sampling rate. Due to the notorious aliasing effect produced by the sampling operation, such resonant modes are difficult to be identified using conventional techniques.
Application of Vertically-Aligned Carbon Nano-Tube for Burnishing Slider in Cleaning Process of Magnetic Disk Surface
Authors: Tani Hiroshi , Konishi K. , Norimatsu W. , Kusunoki M. , Tagawa N.
Published: December 2013

Carbon nano-tubes (CNTs) have certain desirable mechanical properties such as high tensile strength and high flexibility. The frictional properties of non-lubricated CNTs have been previously investigated by certain researchers [1], [2]. In their studies, oriented CNT samples were prepared by chemical vapour deposition (CVD). However, CNTs prepared by CVD generally exhibit weak adhesion with the substrate because, in CVD, a seed layer is required for the growth of CNTs. In this study, we prepared CNTs by the surface decomposition of SiC. CNTs prepared in this manner exhibit stronger adhesion with the SiC substrate because the carbon atoms of the CNTs form a chemical bond with the SiC atoms [3]. On the other hand, the application of dynamic flying height (DFH) control technology to a hard disk drive (HDD) reduces the clearance of magnetic heads above the disk surface to a few nanometers. Further, a little bit of particles, small asperities, and small amount of smear disturb the flyability of magnetic heads. Therefore, the cleanliness of disk surfaces is the important factor for head flyability. Generally, the final tape polishing and the slider burnishing are applied in order to improve the cleanliness of disk surface in manufacturing process. In this study, we focused on the improvement of the burnishing efficiency of burnishing slider by an application of the vertically-aligned CNT for burnishing slider surface.
Illumination and Scattered Light Detection of a Minute Particle Using a Light Source Consisting of Sub-Micrometer Defect Arrays Formed on an Extremely Flat Light Waveguide Core
Authors: Ohkubo Toshifumi , Terada Nobuyuki , Yoshida Yoshikazu
Published: December 2013

A minute optical sensor combined total analysis system (TAS) is thought to be one of the most powerful functional elements needed to realize a “ubiquitous human healthcare” system. In accordance with this concept, we have proposed a fundamental structure of detecting forward and side scattered light from a small cell or particle illuminating laser power through light waveguide formed in a thin resin layer. Based on this concept, we have demonstrated its effectiveness by using a trial-manufactured optical TAS chip, supplying and detecting visible laser power by using multiple optical fibers. Acquiring further various physiological properties created by an internal structure of a particles or cells, it is necessary to illuminate them with a small and arbitrarily-shaped light source placed close vicinity to them.
Effective Parameters of an Auto-Ball Balancer and Modification of its Parameters in a Half-Height Optical Disc Drive
Authors: Oh Wonseok , Lim Seungho , Park Kyoung-Su , Park No-Cheol , Park Young-Pil , Lee Jae-Sung , Lee Han-Baek
Published: December 2013

This research investigates to analyze the effect of ABB parameters on vibration reducing performance. Experiment was performed with respect to the parameters like number of ball, size of ball, mass of pickup base, and friction properties of ABB Race.
Development of a Linear Vibration Motor With Fast Response Time for Mobile Phones
Authors: Nam J. H. , Yeon T. H. , Jang G. H.
Published: December 2013

Linear actuator has been widely used as vibration motor in mobile phones, and it generates a linear vibration through resonance in which the electromagnetic force with the application of a sinusoidal current excites the fundamental natural vibration mode of the moving mass-spring system. Figure 1 shows a linear actuator for mobile phones whose diameter and height are approximately 10 and 1 mm, respectively. The moving coil and mass are attached to a flat spring, and the radial magnetic field between the plate and the moving yoke is generated through a plate connected to the permanent magnet. The magnetic force in the air-gap between the plate and the yoke is generated according to Ampere’s law once the sinusoidal current is applied to the coil, and it excites the axial vibration mode of the linear actuator that generates the axial vibration. The linear actuators have a fast response time compared with other types of vibration motors. Currently, the response time of the linear actuators is approximately 50 msec, but the users and the application software of mobile phones are demanding increasingly faster response time. However, it is very difficult to reduce the response time while maintaining the vibration magnitude under the given constraints of volume and electric power.
Detection of Behaviors Related to Blood Pressure Change Using 6-Axis Kinetic Sensor
Authors: Dai Tingting , Lopez Guillaume , Warisawa Shin’ichi , Yamada Ichiro
Published: December 2013

Continuous blood pressure monitoring in daily life could contribute to early detection of strokes and heart attacks, as well as healthcare promotion. Understanding of what patients were doing when their blood pressure changes occurred would be much more helpful to check the causes of blood pressure changes. However, at present, patients should record their activities by filling the clinical activity record card. The activity record card is so inconvenient that handwriting all the activities becomes a burden and causes inaccuracy. Moreover, it is not able to record posture changes that are a major factor related to short-term blood pressure changes. From these reasons, automatic activities recognition method is strongly required.
Thermo-Molecular Gas-Film Lubrication (t-MGL) Analysis for Heat-Assisted Magnetic Recording Head Slider
Authors: Fukui Shigehisa , Kitagawa Naoya , Wakabayashi Ryo , Matsuoka Hiroshige
Published: December 2013

The present paper analyzes the static lubrication characteristics of a slider flying over a running boundary wall with arbitrary local temperature distributions using the thermo-molecular gas-film lubrication (t-MGL) equation. We obtain two approximate solutions: (i) a linearized solution when the temperature deviation is small (τW ≪1) and arbitrarily distributed, and (ii) a solution for the case with a very large bearing number (Λ → ∞). We herein numerically calculate the static lubrication characteristics and verify the validities of these two approximate solutions. Moreover, we calculate the characteristics for various temperature distributions produced by laser heating.
Vibration Study and Classification of Rotor Faults in PM Synchronous Motor
Authors: Yu Yinquan , Bi Chao , Jiang Quan , Lin Song , Aung Nay Lin Htun , Mamun A. A.
Published: December 2013

Both radial and axial direction Repeatable Run-Out (RRO) and none repeatable Run-Out (NRRO) of spindle motor in HDD is a big concern in high TPI requirement. Besides the reasonable spindle motor structure design which studied in [3]–[4], the fabrication tolerance of spindle motor parts should be controlled in order to minimum RRO and NRRO. As it is known, the vibration of spindle motor is mainly caused by unreasonable Unbalance Magnet Pull (UMP). Different motor parts faults (tolerance is out of the control) will generate different types of UMP which should be generate different vibration signals pattern. Though studying different vibration signals and acoustic noise pattern, the types of UMP or other faults should be detected and classified. then, the related out of tolerance controlled parts can be known. Researchers have studied vibration and acoustic signals in recent years [5][6]–[7]. In this paper, the 12 slots and 5 pole-pairs PM surface mounting Synchronous motor is modified as M1 to do experimental study. This paper can be a guideline of design high performance motor; it also can be the reference of general motor fault diagnosis.
Impact of Touchdown Detection on Bit Patterned Media Robustness
Authors: Juang Jia-Yang , Lin Kuan-Te
Published: December 2013

Bit patterned media (BPM) is considered as a revolutionary technology to enable further increase of areal density of magnetic recording beyond 1 Tbits/in2 [1]. Implementing BPM technology, however, significantly increases the complexity of the recording process, but also poses tremendous tribological challenges on the head-disk interface (HDI) [2]. One of the major challenges facing BPM is touchdown detection by thermal flying-height control (TFC), in which a minute heater located near the read/write transducers is used to thermally protrude a small portion of the slider into contact with the disk, and the contact is then detected by directly or indirectly measuring the friction, temperature rise or vibration caused by the contact [3]–[7]. Most recording heads rely on touchdown detection to achieve a desired flying height (FH), which approaches sub-1-nm regime for many of today’s commercial drives. As a result sensitive and accurate touchdown detection is of critical importance for a reliable head-disk interface by reducing contact duration and unnecessary interaction between the slider and the disk. However, the impact of touchdown on the mechanical robustness of the media has not been properly studied.
Pose Estimation and Simulation of Upper Limb Exoskeleton
Authors: Lin You-Cheng , Jog Sanket , Chang Jen-Yuan (James)
Published: December 2013

In today’s world, there has been an increase in the usage of domestic purpose robots for assisting human activities. Such robots are more effective for physically handicapped people. Sometimes during an accident, person may suffer from a stroke. A stroke occurs when there is a blood clot which blocks the flow of blood due to which a blood vessel breaks, interrupting flow to a particular area of the brain. Functions performed by that area of the brain are lost which include speech, movement, and memory. This paper deals with recovery of human arm movement loss. The wearable exoskeleton robot for upper extremity rehabilitation is taken as the research object. The virtual rehabilitation system was generated in Simulink to carry out dynamic simulation. Robotic rehabilitation has been an effective method since the early 1990’s and is proving to have a significant effect on the fast recovery of stroke affected patients.
Generation of Fuzzy Rules and Learning Algorithms for Servo Control in Holographic Data Storage System
Authors: Kim Jang Hyun , Jeong Wooyoung , Yang Hyunseok
Published: December 2013

Today many media of information storage device are formed as disks. Hence, next generation removable data storage media are shaped as disk types too. The holographic data storage system also uses a disk type photopolymer media. And then, holographic data storage system is most advanced optical memory system. Tracking servo and tilt servo control are very important research in holographic data storage system. In this paper, we propose intelligent servo control by fuzzy rules in holographic data storage system. Hence, we have found pattern of tilt servo control in holographic data storage system through fuzzy system. Fuzzy rules were generated by Genetic algorithm for controlling tilt servo. Therefore, we control tilt servo using fuzzy rules in holographic data storage system. Consequently, practical pattern of tilt servo control was found by intelligence algorithm in holographic data storage system.[1]
Modeling the Traction of a Thin Tape Guided by a Grooved Roller
Authors: Kaşıkcı Tuğçe , Müftü Sinan
Published: December 2013

The Stribeck effect describes the velocity dependence of the friction coefficient between moving components [9]. In the case of an axially translating tape, supported by a roller, air entrainment can cause reduction in the contact pressure, and hence in the tractive capacity of the interface [5]. Grooved rollers are used to prevent excessive built-up of air pressure [6,7,8,1,2]. In this work, tribology and mechanics of a tape-grooved-roller interface is modeled in order to investigate the traction as a function of tape speed, tension and groove size.
A Novel Approach to Build a Learning Controller by Combining Fuzzy Modeling, Sliding Mode, and PID Control for Robotic Applications
Authors: Zeinali Meysar
Published: December 2013

This paper presents a novel approach to combine three powerful methods of control theory and fuzzy c-means clustering algorithm to build a robust learning control for nonlinear uncertain systems such as advance robot manipulators. It is worth noting that the combination not only encompasses the features and capabilities of its components but also the limitations attributed to these techniques (e.g, stability issues of fuzzy controller and poor performance of PID controller in the presence of time-varying uncertainties) may be remedied by each other. To date different combinations of the above mentioned methods presented in the literature each having its own merits and limitations. But, for advance robotics applications such as medical robot, and space applications and with increasing complexity of the robot’s tasks, there is a pressing need for the control systems that are able to learn systematically and efficiently during the course of operation, from its own experience, from the demonstration and also in an unsupervised fashion. The controller proposed in this paper aims at building such a control system using a novel approach to combine adaptive fuzzy modeling algorithm, fuzzy c-means clustering algorithm, adaptive sliding mode control and PID controller. Based on the simulations and experimental results, the proposed controller performs remarkably well in terms of the tracking error convergence and robustness against uncertainties.
Disk Pack DFM Achieving Minimum Flight Height Variations
Authors: Huang Lidu , Ku Chiao-ping Roger , Nguyen Tony , Gong Kevin , Bhargava Puneet , Hirano Toshiki , Huang Fu-Ying
Published: December 2013

As recording area density increases, magnetic recording is approaching near contact regime. Disk deformations, both tangential and circumferential, affect magnetic head flight height (FH) significantly at this FH range, and it becomes increasingly important to magnetic reading and writing performances. Variation in manufacturing process, mechanical tolerance as well as design itself can affect disk deformation greatly. In this presentation, we present a few disk pack design improvements to minimize disk coning and disk crown. The designs are able to achieve consistent disk deformation even under significant manufacturing tolerances.
Rotary Silicon Polymeric Composite Thermal Micro-Actuator
Authors: Yang Jiaping , Tan Cheng Peng , Chong Nyok Boon , Lau Gih Keong
Published: December 2013

This paper reports a new rotary thermal micro-actuator. This new thermal actuator uses a pair of powerful silicon-polymeric composite benders to actuate a magnetic head slider into a rotation when the expandable polymer elements are resistively heated. The advantage is the rotary micro-actuator design can move the read/write head slider with a larger lateral displacement by using a new T-shape central hinge joint as compared to the previous translational design. The experimental results demonstrate that the prototyped device can reach up 314nm displacement by a 4V step voltage. The 1st mechanical resonance frequency has been pushed up to 35 kHz. Simulation shows that the micro-actuator can be subjected to 1000G shock loading under non-operation mode. The large displacement, high resonance frequency and robust shock resistance make the rotary thermal micro-actuator be very suitable for a wide range of precise positioning systems applications including dual-stage positioning systems in disk drives and resonance switches in microsystems.
Numerical Simulation of Fretting Wear at the Dimple/Gimbal Interface
Authors: Tang Zhengqiang , Fu Youyi , Talke Frank E.
Published: December 2013

A numerical model for the simulation of fretting wear at the dimple/gimbal interface of a hard disk drive suspension has been developed. The friction and wear coefficients used in the model are determined from experimental measurements. Archard’s wear equation is implemented numerically and the contact interface geometry is updated incrementally. The von Mises stress distribution and the worn surface profiles are determined.
HAMR HDD Shock Responses
Authors: Huang Lidu , Suzuki Kenzi , Huang Fu-Ying , Hirano Toshiki , Stipe Barry
Published: December 2013

Heat assisted magnetic recording (HAMR) and slim mobile hard disk drives (HDD) are being developed parallelly to maintain cost advantage over the solid state drive (SSD). Operational shock and non-operational shock capabilities are seriously challenged for the slim HDDs due to reduced stiffness (thickness). It is worse for slim HAMR drives due to additional laser diode (LD) and other necessities being added on slider. Shock tests are part of the key performance matrices that must be passed in HDD reliability tests, and the concerns for HAMR mobile drives are, 1) slider lift-off G-level degradation during op-shock, and 2) LD back-to-back hitting during non-operational shock. We studied a few potential HAMR HGA designs, also analyzed a design that improves drive op-shock performances.
Delamination of Ultra-Thin Diamond-Like Carbon Coatings on Magnetic Recording Heads Under Normal Loading
Authors: Price Michael , Ovcharenko Andrey , Thangaraj Raj , Raeymaekers Bart
Published: December 2013

Delamination between an ultra-thin amorphous carbon overcoat, a silicon adhesion layer, and permalloy substrate material of a hard drive recording head is studied during normal loading/unloading of the head disk interface. The effect of normal load and thickness of the silicon adhesion layer on delamination of the Si-permalloy and amorphous carbon-Si interfaces is quantified using a molecular dynamics model. No permanent delamination is found for contact pressures up to 100 MPa, except for the case where a silicon adhesion layer is absent.
A Robust Servo Demodulation Algorithm to Compensate for Head Velocity Induced Error
Authors: Xi Wei , Guo Guoxiao , Yu Jie
Published: December 2013

The fast growing areal density and continuous increasing demand of IOPS and throughput in hard disk drive present great challenges to servo systems on the performance of the track-follow accuracy and seek time. A high bandwidth servo system is required to meet the demand. However, the performance of the servo systems is ultimately limited by the resolution of the position signal which is demodulated form embedded servo sector. Inside the servo sector, the servo track address combining with the servo bursts provide a global position signal of read/write head. The servo track address, which is commonly encoded as gray code, provides coarse position information. Whereas the servo bursts carries the position error signal (PES) to determine the fine position information. There are multiple servo pattern schemes that have been used in hard disk drive, for example, amplitude based servo pattern, phase pattern, and dual frequency pattern [1]. The servo track address and servo bursts span multiple magnetic cycles. The head position is assumed to be unchanged when it travels through the servo sector. The assumption is valid when head is track-following or seeking at low velocity. However, when the head seeks with high velocity, the assumption induces large PE demodulation error, since the head can move as much as a few tracks when it travels through the servo sector. Thereby, it prevents us to use high servo bandwidth for pushing seeking performance. To tackle this problem, we proposed a robust PE demodulation algorithm which can eliminate the head velocity introduced error. The new demodulation algorithm can be generally applied to any servo pattern schemes. The paper is organized as follows. The servo burst modeling and problem formulations are introduced in section I. The velocity based PE demodulation algorithm is presented in section II. The paper concludes with simulation and experiment results.
Lubricant Flow and Accumulation on the Air Bearing Surface of a Hard Disk Drive
Authors: Rodriguez-Mendez Alejandro , Bogy David B.
Published: December 2013

During normal operations of a hard disk drive (HDD), a slider flies over the surface of a spinning disk lifted by a thin layer of air. The disk surface is coated by a molecularly-thin layer of lubricant to protect it against corrosion and reduce wear on the read/write head. The flying height of the slider should be as small as possible in order to achieve higher recording densities. In current HDDs the head-to-disk spacing is on the order of 1–3 nm [1]. At this ultra-low spacing lubricant from the disk often transfers to the slider’s air bearing surface (ABS) forming a thin film that imposes a significant degradation on its performance. Problems such as head instabilities, flying stiction, disk lubricant depletion and increase in head-disk spacing occur when lubricant is present on the ABS [2]. To avoid this condition, modern sliders should be able to remove the lubricant from the ABS as fast as possible. Hence, it is necessary to have a thorough understanding of the lubricant flow process and its driving forces.
An LCL-Lens Array With Electrodes of Interlaced Structure in Applications of Auto-Stereoscopic
Authors: Chao Paul C.-P. , Tu Tse-Yi , Kao Yung-Yuan
Published: December 2013

Commercial auto-stereoscopic display systems have equipped optical lenticular lens sheets in order to realize the function which is able to support two images or views to right and left eyes of viewers. In applications of auto-stereoscopic display, the method of using the lenticular lens sheet, also called time- or spatial-multiplexed method, is first proposed as a patent by Ichinose [1]. The method has more advantages, which includes high luminous performance, movable of eyes position with constant view distance and watchable of multi-viewer. Besides, it can be also easily manufactured to make it very popular. Owing to the superiority, some studies about lenticular lens sheets have been proposed. Berkel et al. [2] have proposed several researches about the method of using lenticular lens sheets on multi-view auto-stereoscopic displays, and he has also proposed that slanted lenticular lens sheets or pixels could be improved the effect of flipped image by boundaries of lens and pixel [3–5]. 2D/3D switchable display is first realized by a method of dual-lenticular lens sheets [6]. Moreover, the method of using lenticular lens sheets has been proposed to be replaced by liquid crystal, LC, lens arrays, [7–9] in order to control viewer distance based on a function of tunable focal length. For the method, some issues of LC lenses should be solved like non-smooth potential in the LC layer and to improve the lens power [10–12].
Positioning Performance Comparison Between Collocated Slider-Driven PZT Actuators and Conventional Suspension-Driven Actuators
Authors: Aruga Keiji
Published: December 2013

The recording density of hard disk drives is achieving the physical limit due to the recording magnet size limitations. Therefore, the bit density BPI (Bits per inch) is saturated. The residual aim is to increase track density TPI (tracks per inch), because reducing mechanical track misregistration has a possibility of increasing TPI. The Dual Stage Actuator using a PZT microactuator which enables better positioning accuracy, is widely used in 3.5 inch high density drives. The latest PZT actuator called a “Milli” actuator drives the whole suspension. However, the mass of the suspension is around several milli-grams, thus the reaction force of PZT driving sometimes causes excitation to attached arm resonance at 8–9 kHz. In addition, the fundamental resonance frequency of a milli-actuator is around 20–25 kHz, the sway frequency of whole suspension.
Skew Estimation and Compensation in Tape Drives With Flangeless Rollers
Authors: Tsuruta Kazuhiro , Pantazi Angeliki , Cherubini Giovanni , Jelitto Jens
Published: December 2013

Magnetic tape remains the medium of choice for long-term data storage at the lowest possible cost. Moreover, tape-cartridge capacities are expected to maintain a compound annual growth rate of about 40%, resulting in a 128 TByte tape-cartridge capacity by 2022, as forecast by the Information Storage Industry Consortium (INSIC) roadmap [1]. To achieve these capacities in future tape products, the data track width has to be aggressively reduced through ultra-precise tape head positioning.
Characterization and Simulation of MIMO Transport Systems in Tape
Authors: Cherubini Giovanni , Pantazi Angeliki , Jelitto Jens
Published: December 2013

The potential for significant capacity and performance improvements in tape storage systems appears to be substantial [1],[2]. Advances in several areas, however, are necessary to foster increases in linear and track densities and consequently achieve higher cartridge capacities and improved performance [3],[4]. Reliable and precise tape transport and track-following servomechanisms are of fundamental importance to guarantee best read-channel performance on all parallel data channels during tape operation. In particular, tight control of tension and potentially of tape-dimensional stability (TDS) variations will be necessary for moving to thinner tape material, which in turn will enable an increase in volumetric density. Figure 1 shows the block diagram of conventional tape transport and track-following servomechanisms in a tape drive [5]. A digital dual servo channel provides estimates of the tape velocity, tape longitudinal position, and head lateral position, which are derived from signals read from dedicated servo bands [6]. Hall sensors provide tape velocity information from the individual reels, which typically is used in the absence of a valid velocity estimate from the servo channel. One of the main impairments affecting the performance of tape drives is the variation of tape tension [7],[8], which may be induced by, e.g., reel eccentricities.
The Analysis of Acoustic Noise and Vibration Generated by the Multi-Layer Ceramic Capacitor
Authors: Ko Byung-Han , Jeong Sang-Geuk , Park Young-Pil , Park Kyoung-Su , Park No-cheol
Published: December 2013

In this study, we analyze the acoustic noise generated by multi-layer ceramic capacitors with the modal test and acoustic noise test. And the relationship between dynamic characteristics of circuit board and acoustic noise was investigated.
Control of Time-Varying Lateral Tape Motion in a Linear-Tape-Open Drive via Adaptive Regulation
Authors: Wang Longhao , de Callafon Raymond A.
Published: December 2013

This extended abstract summarizes a methodology along with the experimental results to adaptively reduce time-varying lateral tape motion (LTM) in a Linear Tape-Open (LTO) drive. For the adaptive regulation, the LTO actuator dynamics is modeled with a Linear Time Invariant (LTI) model and control of time-varying LTM disturbances is done via an adaptable linear feedback controller. Adaptive regulation is done via the direct estimation of a perturbation on the feedback controller. By simultaneously minimizing the variance of the Position Error Signal (PES) and the control output signal, the direct estimation of the controller perturbation is formulated as a weighted estimation problem that is implemented recursively for real-time implementation. The experimental results show a significant reduction of the variance of the PES over different tape cartridges and a constant PES variance during a complete reel-in/out operation of the tape drive.
Gimbal and Slider Vertical Motion Characterization for DSA Servo-Mechanical Design Improvement
Authors: Lu Yi , Wang Xin , Liu Yanning
Published: December 2013

The PZT motor is a critical component for dual stage actuation (DSA) in hard disk drives. When voltage is applied to PZT motors, the suspension with the motors can provide slider off-track motion. Servo control has been focusing on the slider off-track motion because the control loop is designed based on the position error signal (PES) in the off-track direction. However, along with PZT off-track actuation, gimbal and slider vertical motion is inevitably introduced, which may increase head-disk interference risks and even cause lube moguls and ABS (air-bearing surface) wear. In this paper, we present an experimental methodology to investigate the relationship of slider vertical motion and DSA voltage injection.
Intelligent Diagnosis of Bolting System Under Dynamic Impact
Authors: Chen G. (Sheng) , Huang L. , Chang J.-Y. , Chen L. B.
Published: December 2013

The properties of fasteners as significant parts in varied engineering systems have been widely investigated [1–3], from hard disk drive devices to construction ground control. These problems are complex in nature because every bolting involves different sources of nonlinear and uncertainty characteristics. The interfaces forces such as contact forces, friction forces and bonding are not known in reality. The base forces and deformation could be redistributed non-uniformly in the presence of complex loadings such as shock and impact. Most of the reported studies focused on the design issues, characterization of the linear dynamic properties and energy dissipation of bolting system as well as using bolts with integrated detecting systems or dynamometers. The capability to assess the interface properties of bolting system is important for mechatronics, mechanical, civil and mining engineering [1–4]. Even though some conventional approaches have been used to infer bolting integrity, the diagnosis technology has been lacking. This study is conducted to explore the possibility of the diagnosis bolting interface integrity under impact by using accelerometer signal. The statistical pattern identification such as artificial neural network and support vector machine is used to diagnose the bolting integrity. By integrating the analysis and experimental data, an ANN is established as a nonparametric model to predict the system properties. Numerous numerical and experimental researches have been conducted to characterize the typical bolting system, which enables extraction of varied dynamic features from different mechanisms associated with the failures. This kind of database could be used as feature to characterizing the effect of complex loads on bolting for ANN training. To further illustrate the feature extraction, we investigated system models. Due to its adaptive and nonlinear input–output transformation capabilities, artificial neural network (ANN) has been widely applied in the field of pattern and system recognition. The proposed approach is capable of monitoring the stress/strain history and integrity of bolting interface with the goal of detecting structural damage and defects. The results from simulation, testing and ANN identification demonstrated the high performance of the proposed approach compared with conventional ones. In the following, an approach is proposed to reliably estimate the dynamic properties of a bolt-surrounding solid mass specimen using its impact response signal. The developed approach can be readily extended to the bolting connection in other systems such as mechanical and mechatronics systems.
DLC Coatings Characterization on HDD Recording Heads
Authors: Daugela Antanas , Tadepalli Srinivas
Published: December 2013

New magnetic storage technology enhancements are being introduced into the HDD products to facilitate lower head media spacing and reliability. Recently, advanced components such as thermal protrusion devices, Head Disc Interface (HDI) proximity sensors, complex self-compensating AAB designs have been integrated into the recording heads. Component development and product integration teams evaluate performance of these critical head disc interfaces for tribological robustness. New HDI components could potentially bring new HDI wear mechanisms that occur under specific thermo-mechanical conditions. Characterization of recording head DLC overcoat nanoscale wear performance has always been a challenge. Historically, nano-wear tests evolved in conjunction with advances in Scanning Probe Microscopy (SPM) techniques [1] and wear resistive tools [2] like diamond tip cantilevers. Here, by controlling SPM, contact force specified wear patterns can be obtained in contact mode or dynamic mode. Decisions on DLC wear resistance can be made qualitatively by evaluating wear mark topographies.
An Efficient Thermal Actuator Design for the Thermal Flying Height Control
Authors: Li Hui , Shen Shengnan
Published: December 2013

The increasing demanding for higher capacity storage devices continues to push the recoding densities of hard disk drivers to their limit. This has led to a significant decrease in the slider-disk spacing to less than 10 nm. The active-head slider technology has recently been implemented in magnetic recording disk. The thermal flying height control (TFC) sliders are to use a small resistance heater incorporated near the read/write element. By applying a current to the heater, it can change the contour of slider due to the Joule heat induced thermal deformation, thereby controlling the flying height of the slider. Improving the power efficiency and obtaining a large reduction of the flying height are important in the application of thermal flying height control slider.
Neural-Network Based Automatic PID Gain Tuning in the Presence of Time-Varying Disturbances in Hard Disk Drives
Authors: Sun Liting , Chen Xu , Tomizuka Masayoshi
Published: December 2013

In hard disk drive (HDD) systems, disturbances commonly contain different frequency components that are time-varying in nature. Different HDD systems may subject to different excitation disturbances. In this case, it is difficult for fixed-gain PID controllers to maintain a good overall performance. When the characteristics of the disturbances change, or when servos are designed for different drive products, the PID gains have to be retuned. This paper presents automatic online gain tuning of PID controllers based on neural networks. The proposed control scheme can automatically adjust the PID parameters online in the presence of time-varying disturbances, or for different disturbances among different HDD products, and find the optimal sets of PID gains through the self-learning ability of neural networks.
Digital Genomic Quantification of Tumor-Infiltrating Lymphocytes
Authors: Robins Harlan S. , Ericson Nolan G. , Guenthoer Jamie , O’Briant Kathy C. , Tewari Muneesh , Drescher Charles W. , Bielas Jason H.
Published: December 2013

A digital DNA-based assay demonstrates an association between higher TIL counts and improved survival among women with ovarian cancer.
Both Terminal Oxidases Contribute to Fitness and Virulence during Organ-Specific Staphylococcus aureus Colonization
Authors: Götz Friedrich , Mayer Sonja
Published: December 2013

In their recent article, Hammer et al. (N. D. Hammer, M. L. Reniere, J. E. Cassat, Y. Zhang, A. O. Hirsch, M. Indriati Hood, and E. P. Skaar, mBio
4
:e00241-13, 2013) described the dual functions of the two terminal oxidases encoded by
cydBA
and
qoxABCD
in
Staphylococcus aureus
. The aerobic growth of
cydB
or
qoxB
single mutant bacteria was barely affected. However, a
cydB qoxB
double mutant was completely unable to respire and exhibited the small-colony variant phenotype that is typical of menaquinone and heme biosynthesis mutants. The authors found that the two terminal oxidases play a role in pathogenesis. In a systemic mouse infection model, it turned out that in the
cydB
mutant the bacterial burden was significantly decreased in the heart, kidneys, and liver, while in the
qoxB
mutant it was decreased only in the liver. These results illustrate that both terminal oxidases contribute to fitness and virulence, representing promising candidates for the development of antimicrobials.
Hepatic tuberculoma mimicking hepatocellular carcinoma in an immunocompetent host
Authors: Zorbas K , Koutoulidis V , Foukas P , Arkadopoulos N
Published: December 2013

Hepatic tuberculosis as a part of disseminated tuberculosis is seen in 50–80% of cases. Isolated hepatic tuberculosis is very uncommon even in countries with high prevalence of tuberculosis. It can occur as a primary case or due to reactivation of an old tubercular focus. We report a case of a 59-year-old Caucasian woman who presented with persistent right upper quadrant pain and a hepatic lesion on an abdominal CT. She had a history of pulmonary tuberculosis 15 years ago with localised lung tuberculosis treated with lobectomy and antituberculous drugs.
A reversible cause of ‘end-stage renal disease’: discrepant findings in serial duplex ultrasonograms in a suspected occlusion of a renal arterial bypass graft
Authors: Baru Ashvin , Kerns Eric Scott , Cohen David M
Published: December 2013

Duplex ultrasonography may be inaccurate due to a number of variables in operator and patient characteristics. We describe a 40-year-old woman who presented with acute kidney injury after prior complex abdominal aortic surgery that had left her with an essentially solitary functional kidney. On the basis of normal Doppler findings, she was started on dialysis. Owing to high clinical suspicion and a failure of renal function to return, a second Doppler study was performed 3 weeks after the first, revealing the characteristic tardus–parvus waveform of renal artery stenosis. The patient underwent urgent renal arterial angioplasty and stent placement. She experienced an immediate increase in urinary output, required no further dialysis, and the creatinine improved to 1.7 mg/dL (her prior renal baseline). The case illustrates an important complication of abdominal aortic aneurysm repair, draws attention to a potential source of error in the Doppler measurement, and underscores the limitations of duplex ultrasonography for excluding renal artery stenosis in the presence of high pretest probability.