Laser optical disk position encoder with active heads

An angular position encoder that minimizes the effects of eccentricity and other misalignments between the disk and the read stations by employing heads with beam steering optics that actively track the disk in directions along the disk radius and normal to its surface is discussed. The device adapts features prevalent in optical disk technology to the application of angular position sensing

Study of the modifications needed for effective operation NASTRAN on IBM virtual storage computers

The necessary modifications were determined to make NASTRAN operational under virtual storage operating systems (VS1 and VS2). Suggested changes are presented which will make NASTRAN operate more efficiently under these systems. Estimates of the cost and time involved in design, coding, and implementation of all suggested modifications are included

Real-time simulation of jet engines with digital computer. 1: Fabrication and characteristics of the simulator

The fabrication and performance of a real time jet engine simulator using a digital computer are discussed. The use of the simulator in developing the components and control system of a jet engine is described. Comparison of data from jet engine simulation tests with actual engine tests was conducted with good agreement

Analysis of SSD’s Performance in Database Servers

Data storage is much needed in any type of device and there are multiple mechanisms for data storage which vary from the device to device but at the end it’s a magnetic drive which holds the data and stored in the form of digital format. One predominant data storage device is hard disk drive also called as HDD. Hard disk drives are used in a wide range of systems like computers, laptops and netbooks etc., it has magnetic platter which is used for reading and writing operations. (Hard disk drive, n.d.) With the emerging technologies and modularization of web application design architecture created a need for different kind of operating system and system architecture based on the functionality. If we want a server where files need to be placed it should be designed in such a way that it needs to be good at input and output operations (I/O). (How does a hard drive work?, 2018) If we want to store videos and stream, that server should be good at asynchronous streaming functionality. If we need to store the structured/un-structured data which can be pertained to any educational institution or an organization, we can use a database server to store this data in tables and it can be used. In general, we use hard disk drives to store any kind of data in all the servers, but there will be only changes in the system architecture. The concept of HDD utilization has been constant from past 20 years. There was a huge growth in the architectural design of operating systems used for hosting database servers, but when it comes to storage HDD’s have been used for many years. With the need for speed and faster operations from the perspective of storage, solid state drives come in to picture. (SSD Advantage, n.d.)They have a different kind of architecture when compared to HDD and they are called as SSD. This paper discusses the idea of using SSD’s instead of HDD’s in database servers. We created multiple database instances for SSD’s and HDD’s and also created multiple web applications using JAVA and connected to each of these database servers to access data via REST API’s. We have run multiple tests to compare the load time of all the different database instances and generated some visual analytics how it behaves when multiple/series of get operations made on the database with the REST API. This analysis will help in finding if there are any anomalies in the behavior with increase in throughput of read and write operations

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 43)

Abstracts are provided for 128 patents and patent applications entered into the NASA scientific and technical information system during the period Jan. 1993 through Jun. 1993. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

Database machines in support of very large databases

Software database management systems were developed in response to the needs of early data processing applications. Database machine research developed as a result of certain performance deficiencies of these software systems. This thesis discusses the history of database machines designed to improve the performance of database processing and focuses primarily on the Teradata DBC/1012, the only successfully marketed database machine that supports very large databases today. Also reviewed is the response of IBM to the performance needs of its database customers; this response has been in terms of improvements in both software and hardware support for database processing. In conclusion, an analysis is made of the future of database machines, in particular the DBC/1012, in light of recent IBM enhancements and its immense customer base

Silicon micromachined SCALED technology

Silicon micromachining technology will play an important role in the fabrication of high-bandwidth servo controlled microelectromechanical (mechatronic) components for super-compact disk drives. At the University of California, Los Angeles, and the California Institute of Technology, for the last three years, we have initiated a number of industry-supported joint research projects to develop the necessary technology building blocks for an integrated drive design of the future. These efforts include a silicon read/write head microgimbal with integrated electrical and mechanical interconnects, which targets the next-generation 30% form factor pico-sliders, and an electromagnetic piggyback microactuator in super-high-track-density applications, both of which utilize state-of-the-art silicon micromachining fabrication techniques

Nanotribology and Nanomechanics of Thin Films Including Material Characterization, Mechanical Wear, Adhesion and Lubrication

The present work is dedicated to addressing nanotribological issues of ultra-thin (sub-10 nm) films at contacting interfaces. In devices such as micro-electro-mechanical systems (MEMS), thin films are deposited for specific functions. In some occasions, mechanical durability of the thin films is also important. Magnetic storage hard disk drives (HDD) are a good example where nanotribology at the head-disk interface (HDI) is extremely important. Especially in recent years, where the areal density increases exponentially and the write/read head has been brought as close to as less than 10 nm to the disk surface. As a result, direct contact is possible to occur at such small distance and such unfavorable contact will cause mechanical wear and demagnetization. Nanometer thick diamond like carbon (DLC) and lubricant films provide important protection and study of their failure mechanisms is necessary. The present thesis has conducted research to understand the nanotribology of thin films in the multilayered system used in HDDs. The majority of the work is measurement of the nanomechanical and nanotribological properties of the solid thin films with thickness of less than 20 nm. A method combining finite element analysis (FEA) and nanoindentation was proposed to extract nanomechanical properties from nanoindentation data for multilayered samples. A highly sensitive nanomechanical transducer was introduced to perform sub-5 nm shallow nanoindentation experiments on thin films deposited at different conditions. To study the tribological performance of DLC films at high temperatures up to 300 °C, the present work performs nanoscratch and nanowear tests on a 3-nm thick DLC film. The results show the wear rate of DLC films begin to increase abruptly at around 200°C and this degradation of wear resistance is irreversible. The present thesis also proposes a mathematical model to quantitatively predict the hydrodynamic lubrication effects of the molecularly thin lubricant between the head and the disk surfaces. After considering the nanorheological behavior of the lubricant, the model is able to make predictions of contacting forces and pressures and explain the tribological role of the lubricant in terms of continuum mechanics. Lastly, present thesis proposed a model considering Van der Waals forces between lubricants on the disk and on the head. The proposed model provides stricter criterion for onset of adhesion induced lubricant-transfer between the two wet surfaces and is in better agreement with Molecular Dynamics simulations than conventional models. In summary, the findings above center about nanomechanics and nanotribology at the interfaces of the magnetic storage hard disk. However, these findings can also extend their applications to other MEMS devices where tribology issues are of important concerns. The shallow nanoindentaton instrument and FEA-based characterization method can be applicable any other solid thin films. The high-temperature tribological properties of a ultra-thin DLC films utilize a unique test rig but the findings are generally instructive in understanding behaviors of DLC at high temperature. The nano-lubrication model for a lubricated single asperity can be an addition of current contact mechanics which usually neglects the presence of lubricants