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1.
Experiments on slider lubricant interactions and lubricant transfer using TFC sliders 总被引:1,自引:1,他引:0
Future magnetic storage density targets (>4 Tb/in. 2) require subnanometer physical clearances that pose a tremendous challenge to the head disk interface (HDI) design. A detailed understanding of slider-lubricant interactions at small clearances and contact is important to not only address magnetic spacing calibration and long term HDI reliability but also to meet additional challenges imposed by future recording architectures such as heat assisted magnetic recording (HAMR). In this work, the behavior of the disk lubricant is investigated through controlled tests using TFC sliders which are actuated to proximity (i.e. backoff) and into contact (i.e. overpush) on one specific half of the disk per rotation by synchronization with the spindle index. Observations for lubricant distribution in contact tests (i.e. overpush) reveal an accumulation of lubricant on the disk near the onset of contact suggesting a migration of lubricant from the slider to the disk as the slider approaches the disk. Experiments also reveal that there is a similar deposition of lubricant even in the absence of contact for backoff tests. Furthermore, light contact tests result in significant lubricant rippling and depletion with associated slider dynamics. The lubricant rippling frequencies correlate well with the slider’s vibration frequencies. Interestingly, strong overpush may lead to stable slider dynamics (for certain air bearing designs) that is also associated with noticeably lower lubricant distribution (compared to the light contact case), and the greatest lubricant changes are observed only at the onset and the end of contact. This paper reveals the complex nature of slider-lubricant interactions under near-contact and contact conditions, and it highlights the need for further studies on the topic to help design a HDI for recording architectures of the future. 相似文献
2.
BACKGROUND: Hydronephrosis secondary to pelviureteric junction (PUJ) obstruction is common in infancy and childhood. Pyeloplasty has until recently been the accepted method of management, but alternative endo-urological techniques have evolved in the last decade. METHODS: Published results of conventional pyeloplasty for primary PUJ obstruction in children were compared with published results of endo-urological procedures. RESULTS: Sixty-six pyeloplasties were performed in 61 children in a 6-year period. During a similar period, 63 primary endo-urological procedures were reported in the literature. The success rate after pyeloplasty was 95.5% compared with 65% after endo-urology. CONCLUSIONS: Conventional pyeloplasty is superior to endo-urology and should remain the gold standard for the treatment of primary PUJ obstruction in children. 相似文献
3.
Avula Edukondalu T. Sripathi Shaik Kareem Ahmmad Syed Rahman K. Sivakumar 《Journal of Electronic Materials》2017,46(2):808-816
Glass with compositions xK2O-(30 ? x)Li2O-10WO3-60B2O3 for 0 ≤ x ≤ 30 mol.% have been prepared using the normal melt quenching technique. The optical reflection and absorption spectra were recorded at room temperature in the wavelength range 300–800 nm. From the absorption edge studies, the values of the optical band gap (E opt) and Urbach energy (ΔE) have been evaluated. The values of E opt and ΔE vary non-linearly with composition parameter, showing the mixed alkali effect. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple Di-Domenico model. 相似文献
4.
Chalcogenide thin films are used as the recording medium for phase change-type optical memory discs. The films are switched
between amorphous and crystalline states using the heat of a focussed laser beam. Large reflectivity differences between amorphous
and crystalline states are then used to store and retrieve the information. An active chalcogenide layer for this purpose
should have a high optical absorption coefficient (α), and good structural and thermal stability. It should be possible to
switch the chalcogenide layer between amorphous and crystalline states repeatedly within a short duration, the optical contrast
should be high, and the material must have large cycling capability. Keeping the above requirements in mind, we have carried
out systematic investigation of structural, optical and crystallization behaviour of thin films of various compositions of
GaGeTe, Sb2Te3 and BiSe. These studies have shown that these materials can be good candidates for use as recording media in erasable phase-change
optical recording. 相似文献
5.
Y. Sripathi G. B. Reddy L. K. Malhotra 《Journal of Materials Science: Materials in Electronics》1992,3(3):164-167
Bi
x
Se1–x
thin films have been studied because of their structural and optical properties with a view to judging their suitability as the recording medium in phase-change type optical recording. Amorphous films deposited at room temperature were crystallized by thermal annealing. X-ray diffraction analysis and surface morphological studies are reported. A maximum reflectivity difference of 25% at =830 nm was obtained upon amorphous-to-crystalline transition. The optical constants calculated by the Newton-Raphson method using the experimental transmittance, reflectance and thickness data are reported. 相似文献
6.
In this paper, a new layered cellular manufacturing system is proposed to form dedicated, shared and remainder cells to deal with the probabilistic demand, and later its performance is compared with the classical cellular manufacturing system. In the layered cellular design, each family may need more than one cell to cover capacity requirements. The proposed approach for layered cellular design involves five stages: (1) product clustering, (2) identifying number of cells and demand coverage probabilities, (3) determining cell types using the proposed heuristic procedure, (4) performing simulation to determine operating conditions and (5) statistical analysis to pick the best design configuration among layered cellular designs. Simulation and statistical analysis are performed to help identify the best design within and among both layered cellular design and classical cellular design. It was observed that as the number of part families increased, the number of machines needed to process the parts decreased first. Then the number of machines started to increase once again as the number of part families continued to increase. Another observation was that the average flow time and total WIP were not always the lowest when additional machines were used by the system. The last and the most important observation was that the layered cellular system provided much better results than the classical cellular system when high demand fluctuation was observed. 相似文献
7.
Utilizing Low‐Cost Eggshell Particles to Enhance the Mechanical Response of Mg–2.5Zn Magnesium Alloy Matrix 下载免费PDF全文
Gururaj Parande Vyasaraj Manakari Sripathi Dev Sharma Kopparthy Manoj Gupta 《Advanced Engineering Materials》2018,20(5)
8.
Aarti Sripathi BhattDenthaje Krishna Bhat 《Materials Science and Engineering: B》2012,177(2):127-131
Organic-inorganic nanocomposites are gaining importance in the recent times as polymer electrolyte membranes. In the present work, composites were prepared by combining nano sized Co3O4 and poly(vinyledene fluoride) (PVDF), using spin coating technique. The surface of the PVDF/Co3O4 system characterized through field emission scanning electron microscopy (FESEM) revealed a porous structure of the films. The nanoparticles tend to aggregate on the surface and inside the pores, leading to a decrease in the porosity with an increase in Co3O4 content. Co3O4 nanoparticles prohibit crystallization of the polymer. Differential scanning calorimetry (DSC) studies revealed a decrease in crystallinity of PVDF/Co3O4 system with an increase in the oxide content. Magnetic property studies of the composite films revealed that with an increase in Co3O4 content, the saturation magnetization values of the nanocomposites increased linearly, showing successful incorporation of the nanoparticles in the polymer matrix. Further, ionic conductivity of the composite films was evaluated from electrochemical impedance spectroscopy. Addition of Co3O4 nanoparticles enhanced the conductivity of PVDF/Co3O4 system. 相似文献
9.
Autoimmune serological testing is a useful aid for identifying a paraneoplastic basis for sporadic motor neuron disease. A 67-year-old woman with ovarian carcinoma presented with progressive weakness. Neurological examination was suggestive of motor neuron disease with signs of upper motor neuron disorder. Electromyography revealed severe motor neuronopathy of the upper extremities. Characteristic type 1 Purkinje cell antibodies (anti-Yo antibody) was detected in the serum diluted at 1:61,400. 相似文献
10.
The causes of visual loss in 1411 children attending schools for the blind in different geographical areas in India are described. Ninety-three percent (1318) of the children were severely visually impaired (SVI) or blind (i.e. corrected acuity in the better eye of <20/200 [<6/60]). In 60% of SVI/blind children vision loss was attributable to factors operating in the prenatal period, in 47% the prenatal factors were known and definite, and in 13% prenatal factors were the most probable causes. Hereditary retinal dystrophies and albinism were seen in 19% of SVI/blind children and 23% had congenital ocular anomalies. There were variations in the relative importance of different causes by state. The observed pattern of causes of visual loss is intermediate between those seen in industrialised countries and in the poorest developing countries. This suggests that strategies to combat childhood blindness in India need to address concurrently both preventable and treatable causes. The need for aetiological studies, particularly on anophthalmos and microphthalmos, is highlighted. 相似文献