Thermal Stresses in Cooled Heat-Releasing Elements of Electronic Devices

2009 ◽  
pp. 123-123-10
Author(s):  
A Parnas
Keyword(s):  
Thermal Stresses ◽  
Electronic Devices

The Identification of Thermal Fatigue Testing Method of Soldered Joints for Space Use

1997 ◽  
Author(s):  
M. Yonemaru ◽  
A. Shimizu ◽  
S. Matsuda ◽  
I. Seo
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Thermal Stresses ◽  
Fatigue Testing ◽  
Electronic Devices ◽  
Space Use ◽  
Test Method ◽  
Space Applications ◽  
Thermal Fatigue Life ◽  
Test Parameters

Abstract Electronic devices have been used under various thermal conditions in space applications. The temperature range often exceeds 100°C, and the electronic devices are stressed by both high and low temperatures and thermal cycles. Since repairing and reworking of the spacecraft electronic hardware cannot be performed after launch, verifying the reliability of the hardware on the ground before the launch is essential. The thermal stresses to the electronic devices' soldered joints have recently tended to increase because the devices must be made smaller and lighter. The thermal fatigue of the soldered joints must be addressed in order to achieve highly reliable flight hardware. We studied a test method to estimate the thermal fatigue life of soldered joints for space use. This paper examines the thermal fatigue life using two kinds of test methods as heat-resistant evaluation tests of soldered joints for space use, and evaluates the effect of the test parameters on the thermal fatigue life of soldered joints. We conclude that the thermal fatigue life of soldered joints cannot be estimated accurately, if the test parameters are instituted uniformly.

Atom-probe analysis of the solid-liquid interface

1995 ◽  
Vol 53 ◽  
pp. 676-677
Author(s):  
J.A. Panitz
Keyword(s):  
Molecular Level ◽  
Selective Adsorption ◽  
Electronic Devices ◽  
Atom Probe ◽  
Chemical Agent ◽  
Hostile Environment ◽  
Solid Interface ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Chemically Selective

The first few atomic layers of a solid can form a barrier between its interior and an often hostile environment. Although adsorption at the vacuum-solid interface has been studied in great detail, little is known about adsorption at the liquid-solid interface. Adsorption at a liquid-solid interface is of intrinsic interest, and is of technological importance because it provides a way to coat a surface with monolayer or multilayer structures. A pinhole free monolayer (with a reasonable dielectric constant) could lead to the development of nanoscale capacitors with unique characteristics and lithographic resists that surpass the resolution of their conventional counterparts. Chemically selective adsorption is of particular interest because it can be used to passivate a surface from external modification or change the wear and the lubrication properties of a surface to reflect new and useful properties. Immunochemical adsorption could be used to fabricate novel molecular electronic devices or to construct small, “smart”, unobtrusive sensors with the potential to detect a wide variety of preselected species at the molecular level. These might include a particular carcinogen in the environment, a specific type of explosive, a chemical agent, a virus, or even a tumor in the human body.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

Study of dislocation loops in Arsenic-Rich as-grown GaAs

1987 ◽  
Vol 45 ◽  
pp. 350-351
Author(s):  
Byung-Teak Lee
Keyword(s):  
Point Defects ◽  
Electronic Devices ◽  
Arsenic Concentration ◽  
Stoichiometric Compound ◽  
Dislocation Loops ◽  
Gaas Crystal ◽  
Ion Milling ◽  
Transmission Electron ◽  
Arsenic Source ◽  
High Arsenic

Grown-in dislocations in GaAs have been a major obstacle in utilizing this material for the potential electronic devices. Although it has been proposed in many reports that supersaturation of point defects can generate dislocation loops in growing crystals and can be a main formation mechanism of grown-in dislocations, there are very few reports on either the observation or the structural analysis of the stoichiometry-generated loops. In this work, dislocation loops in an arsenic-rich GaAs crystal have been studied by transmission electron microscopy.The single crystal with high arsenic concentration was grown using the Horizontal Bridgman method. The arsenic source temperature during the crystal growth was about 630°C whereas 617±1°C is normally believed to be optimum one to grow a stoichiometric compound. Samples with various orientations were prepared either by chemical thinning or ion milling and examined in both a JEOL JEM 200CX and a Siemens Elmiskop 102.

Educational STEM designing of virtual and real devices on the Arduino platform

2020 ◽  
pp. 17-27
Author(s):  
S. G. Grigoriev ◽  
M. V. Kurnosenko ◽  
A. M. Kostyuk
Keyword(s):  
Virtual Environments ◽  
Electronic Devices ◽  
Practical Training ◽  
Full Time ◽  
Stem Design ◽  
Face To Face ◽  
Interdisciplinary Knowledge ◽  
Virtual Modeling ◽  
Surface Mounting

The article discusses possible forms of educational STEM projects in the field of electronics and device control using Arduino controllers. As you know, the implementation of such STEM projects can be carried out not only using various electronic constructors, but also using virtual modeling environments. The knowledge obtained during modeling in virtual environments makes it possible to increase the efficiency of face-to-face practical training with a real constructor, and to improve the quality of students’ knowledge. The use of virtual modeling environments in combination with the use of real constructors provides links between distance and full-time learning. A real constructors can be used simultaneously by both the teacher and the student, jointly practicing the features of solving practical problems. The article provides examples of using a virtual environment for preliminary prototyping of circuits available in the documentation for electronic constructors, to familiarize students with the basics of designing and assembling electronic circuits using the surface mounting method and on a breadboard, as well as programming controllers on the Arduino platform that control electronic devices. This approach allows students to accelerate the assimilation of various interdisciplinary knowledge in the field of natural sciences using STEM design.

PENGGUNAAN INTERNET OF THINGS DALAM PEMASARAN PRODUK PERTANIAN

2018 ◽  
Vol 3 (2) ◽  
pp. 74
Author(s):  
Helina Apriyani ◽  
Sismadi Sismadi ◽  
Sefrika Sefrika
Keyword(s):  
Cloud Computing ◽  
Internet Of Things ◽  
Data Storage ◽  
Electronic Devices ◽  
Agricultural Products ◽  
Main Concept ◽  
Farmers Market ◽  
Incremental Method ◽  
Sales Process ◽  
Internet Connections

AbstrakInternet of things (IoT) adalah sebuah konsep yang menghubungkan komputer dan perangkat elektronik melalui internet dan dapat dikendalikan dari jarak jauh. Konsep terpenting dalam Internet of things (Iot) adalah modul sistem informasi, koneksi internet dan penyimpanan datanya dalam cloud computing. Konsep ini memiliki manfaat besar dalam perkembangan usaha dan kelangsungan bisnis perusahaan dimana hampir semua bidang menggunakan IoT untuk dapat bersaing di pasaran. Indonesia merupakan sebuah negara yang dianugerahi kekayaan alam yang melimpah ruah. Salah satu komoditi unggulan adalah produk pertanian. Penelitian ini bertujuan untuk membantu para petani dalam memasarkan produknya melalui e-commerce dengan menggunakan konsep Internet of things IoT. Metode penelitian dengan menggunakan metode incremental.  Incremental digunakan untuk mendesai produk, kemudian  diimplementasikan, dan diuji secara bertahap (setiap modul akan ditambahkan bertahap) hingga produk selesai. Hasil penelitian ini digunakan untuk membantu petani di Kabupaten Bogor untuk mendistribusikan penjualannya secara luas, meningkatkan revenue dan memutus rantai panjang proses penjualan. Kata kunci— sistem penjualan, incremental, Internet of Things (IoT), produk pertanian, Kabupaten Bogor Abstract Internet of things (IoT) is a concept that connects computers and electronic devices via the internet and can be controlled remotely. The main concept in Internet of things (IoT) is information systems, internet connections and data storage in cloud computing. This concept has great benefits in the efforts and efforts used to use IoT to be able to compete in the market. Indonesia is a country that is blessed with abundant natural resources. One of the leading commodities is agricultural products. This study aims to help farmers market their products through e-commerce using the IoT Internet of things concept. Research method using incremental method. Incremental to design the product, then implemented, and gradually delay (each module will be added gradually) until the product is finished. The results of this study are to help farmers in Bogor Regency to distribute sales widely, increase revenue and break the sales process. Keywords—sales system, incremental, Internet of Things (IoT), agricultural products, Kabupaten Bogor

A Survey on Crypto-Steganographic Schemes and A Use Case in Healthcare System

2019 ◽  
Vol 1 (2) ◽  
pp. 25-33
Author(s):  
Mei Ling Phang ◽  
Swee Huay Heng
Keyword(s):  
Social Networking ◽  
Information Sharing ◽  
Healthcare System ◽  
Double Layer ◽  
21St Century ◽  
Electronic Devices ◽  
Third Party ◽  
Use Case ◽  
Comparison Analysis ◽  
Information Assets

Information sharing has become prevalent due to the expansion of social networking in this 21st century. However, electronic devices are vulnerable to various kinds of attacks. Information might be disclosed, modified and accessed by an unauthorised third party which consequently leads to the breach of confidentiality, integrity and availability of the information. Therefore, it is of utmost importance to employ the technology of cryptography and steganography to protect information assets. Cryptography and steganography have weaknesses when they are working alone. Therefore, crypto-steganography, the combination of cryptography and steganography are introduced to overcome the weaknesses in order to provide a double layer of security and protection. This paper provides a general overview of steganography and cryptography as well as a comparison analysis of different crypto-steganographic schemes. A secure crypto-steganographic system for healthcare is then developed with the implementation and integration of the secure crypto-steganographic scheme proposed by Juneja and Sandhu. This healthcare system enables users to store and deliver message in a more secure way while achieving the main goals of both cryptography and steganography.

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