The Effect of Process on Performance and Reliability in a One Step Silver-Glass Die Attach Adhesive

1991 ◽  
Vol 226 ◽  
Author(s):  
A.M. Conlon ◽  
C.P. Cameron ◽  
J.W. Lau

AbstractSilver-glass die attach adhesives provide a cost effective means of producing high reliability parts which can withstand the environmental testing required of electronic components. One step processing of these adhesives provides the additional advantages of increased throughput and processing flexibility compared to eutectically bonded assemblies.This paper describes the performance of a one step silver-glass die attach adhesive processed under various time and temperature conditions. The effect of peak firing temperature and dwell time on the ultimate tensile strength of the adhesive will be discussed. Tensile data from parts subjected to thermal shock, thermal cycle and high temperature aging will be presented as an indication of the material's long term reliability.

2020 ◽  
Vol 8 (9) ◽  
pp. 3010-3016 ◽  
Author(s):  
Chunhua Su ◽  
Meijia Qiu ◽  
Yipeng An ◽  
Siyuan Sun ◽  
Chuanxi Zhao ◽  
...  

Long-term stable, fast switching α-Ni(OH)2 electrodes for electrochromic energy storage application has been fabricated by one-step preheating treatment. The cost-effective fabrication is expected to expand to other metal hydroxide materials.


2020 ◽  
Vol 4 (4) ◽  
pp. 209-218
Author(s):  
S. M. Golovanov ◽  
V. I. Orlov ◽  
V. V. Fedosov

In modern conditions in the Russian Federation the equipment of spacecraft with a highly reliable electronic components is possible only through testing technical centers which act as a link between manufacturers of electronic components and their consumers. Given the lack of specialized production of electronic components of the «Space» category in our country, this is the only alternative way. Testing technical centers carry out the formation of batches of electronics for space applications by conducting additional tests of electronic components for general industrial use allowing the rejection of elements containing defects that can manifest themselves during long-term operation in outer space. A modern spacecraft contains about 100–200 thousand electronic components. Taking into account the fact that the on-board equipment of the spacecraft during its operation cannot be repaired, it is obvious that extremely high reliability requirements are imposed on the electronic components of space applications. In this regard the improvement of the methodology for increasing the reliability of the electronic components of space applications is of paramount importance for the further development of the space industry. This article outlines an approach to improving the technology of additional tests in testing technical centers, based on the use of the concepts of homogeneity of the tested batch of electronic components which makes it possible to meaningfully generate samples for destructive physical analysis and radiation resistance tests, as well as to additionally identify emission elements that are potentially unreliable elements.


2020 ◽  
Author(s):  
Wuyou Sui ◽  
Jonathan Rush ◽  
Ryan E. Rhodes

BACKGROUND The COVID-19 pandemic has dramatically changed the physical activity (PA) landscape through the closures of gyms, recreational facilities, schools, and many outdoor spaces. Physical distancing and stay-at-home public health guidelines have also reduced opportunity for PA. In turn, the popularity of online home workout and fitness videos, particularly those hosted on free video streaming platforms like YouTube and Instagram, has spiked during the pandemic. These online exercise videos offer viewers a convenient, accessible, and cost-effective means of engaging in PA, typically through regularly posted videos or discrete programs spread over a number of days. Notably, traditional PA and exercise programs often suffer from poor adherence and high dropout rates, despite many advantages over online workout programs (e.g., specialized equipment, real-time feedback, in-person social engagement). Thus, while there are clear advantages to these online fitness videos, their ability to maintain long-term engagement and adherence is unknown. OBJECTIVE This study explored patterns of engagement (i.e., for online fitness videos posted by channels since the declaration of COVID-19 over four months. A secondary objective was to examine potential moderators of engagement metrics. METHODS An environmental scan was used to identify eligible channels. Eligible channels were (i) freely available on YouTube or Instagram and (ii) posted daily or weekday series workouts OR offered quarantine-specific workout programs. Searches were conducted on June 1 and 4, 2020. Engagement metrics of views, likes, and comments were collected from videos posted between March 11 to June 26 or 30, 2020, inclusive. A series of multilevel modeling analyses were conducted to examine longitudinal changes in each of the three outcome variables (i.e., views, likes, and comments). RESULTS Ten channels were deemed eligible and included in analyses; six channels posted regularly, while the other four posted discrete workout programs. Multilevel models revealed that both views and likes significantly decreased across days. Visually, channels display the sharpest drop in engagement within the first week. Linear change estimate indicates that the number of views were initially declining by 24,700 per day, on average across all the channels. Channels that had more subscribers declined in their views, likes, and comments at a significantly faster rate compared to channels with fewer subscribers. The day of the week a video is posted, ‘virality’, and content of a video all appear to influence engagement. CONCLUSIONS Regardless of raw engagement metrics, each channel demonstrated peak engagement with the initial video followed by a decline in engagement with subsequent videos. As many countries continue to maintain restrictions on traditional PA facilities due to COVID-19, determining methods to improve engagement and adherence with online fitness videos becomes increasingly important.


2007 ◽  
Vol 39 (3) ◽  
pp. 765-780 ◽  
Author(s):  
Maria Mauceri ◽  
Jeffrey Alwang ◽  
George Norton ◽  
Victor Barrera

Potato farmers in Ecuador rely on chemical inputs to manage pests and optimize yields. Integrated pest management techniques lower production costs, reduce pesticide exposure, and improve long-term agricultural sustainability. Public extension does not, however, exist in Ecuador, and cost-effective means of communicating complex messages to producers are needed. We analyze cost-effectiveness of alternative dissemination methods, including farmer field schools (FFS), field days, pamphlets, and word-of-mouth transmission. Field days and pamphlets have strong impacts on adoption, especially considering their low costs. FFS are effective, but expensive. Evidence also indicates significant diffusion from FFS to non-FFS farmers, indicating high complementarity across methods.


1988 ◽  
Vol 1 (21) ◽  
pp. 182
Author(s):  
Orville T. Magoon ◽  
Joan L. Pope ◽  
Robert L. Sloan ◽  
Donald D. Treadwell

Appropriately designed, constructed, and maintained rubble mound seawalls are an efficient and cost-effective means of protecting erodible sections of exposed coastline. This conclusion is supported by more than 25 years of satisfactory seawall performance along the Pacific Ocean coast of Santa Cruz County, California, U.S.A. Important factors in satisfactory seawall performance include a clear understanding of the oceanographic and geologic design parameters, a vigorous inspection program during construction, and continued observation and maintenance of the structures.


2021 ◽  
Author(s):  
Pradeep Lall ◽  
Aathi Raja Ram Pandurangan ◽  
Ken Blecker

Abstract Fine Pitch Electronic Components are reinforced using epoxy potting compounds and underfills to improve reliability and survivability, in extreme environments. Potting of electronic components offers structural support, shock damping and protection for the components from environmental conditions like moisture. Potting is one of the cost-effective and viable way to improve the survivability of the electronic components. On dynamic shock loading, interfacial delamination occurs between the potting material and the PCB, which further propagates to solder interconnect failures. The interfacial properties change with long-term exposure to temperature during operating and storage conditions. Mechanics of interface delamination of the epoxy potted PCB samples with thermal aging is a primary focus on this paper. Determination of fracture parameters such as fracture toughness and strain energy release rate at steady state stress is important in selection of the potting material and the reliability study of the supplemental restraint systems. PCB/Epoxy specimens are prepared, and their fracture behavior is observed under quasi-static three-point and four-point bend loading. In three-point bending, the peak stress acts at the midpoint of the specimen. In four-point bend loading, the peak stress is along whole area of the specimen under load (load span). The curing temperature providing the best fracture resistance is selected and followed throughout the study. The samples are exposed to 100°C for 30days and 60 days. Under dynamic loading, damage at the interface is studied. The experimental results provide the peak critical load, from which the fracture toughness parameters are calculated. A comparison has been made on fracture toughness and crack initiation of the PCB/Epoxy systems, based on flexure method and thermal aging.


Author(s):  
Daniel S. Janikowski ◽  
Edward R. Blessman

The stainless steel feedwater heater specifications, ASTM A688/ASME SA 688 and ASTM A803/SA 803, were developed over 30 years ago. At that time, no one envisioned the temperatures and pressures that today’s super and ultra-critical units would operate. The increased pressures, temperatures, and expectations for reliability require special manufacturing techniques and testing for long tube life. The current ASTM/ASME specifications should be considered minimum requirements, and for long term reliability a number of additional special manufacturing processes and tests are essential. This paper summarizes many of the manufacturing and testing choices that should be specified to ensure high reliability. It identifies the advantages and disadvantages of each option and provides suggestions on what should be specified to ensure a reliable cost-effective feedwater heater tube for today’s applications.


1990 ◽  
Vol 6 (2) ◽  
pp. 203-222 ◽  
Author(s):  
G. R. McKay ◽  
H. E. Chapman ◽  
D. K. Kirkcaldie

Seismic isolation of structures has been applied in New Zealand since 1973. To date approximately 45 bridges, 3 large buildings and a few other structures have been protected with this technique. These include 40 bridges and 2 buildings designed by Works and Development Services Corporation (NZ) Ltd (WORKS). Numerous energy dissipating devices have been developed and tested by New Zealand researchers. Six of these designs have proved to be convenient and economical and have been incorporated in the seismic isolation systems of the structures built. Development work on seismic isolation devices is continuing in New Zealand and contact with specialists from other countries - in particular from Japan and the United States of America - is being maintained. Seismic isolation has been found to be a cost effective means of mitigating earthquake effects, particularly if the long term benefits of reduced seismic damage and disruption are taken into consideration.


2015 ◽  
Vol 20 (4) ◽  
pp. 242-251 ◽  
Author(s):  
Éva Kállay

Abstract. The last several decades have witnessed a substantial increase in the number of individuals suffering from both diagnosable and subsyndromal mental health problems. Consequently, the development of cost-effective treatment methods, accessible to large populations suffering from different forms of mental health problems, became imperative. A very promising intervention is the method of expressive writing (EW), which may be used in both clinically diagnosable cases and subthreshold symptomatology. This method, in which people express their feelings and thoughts related to stressful situations in writing, has been found to improve participants’ long-term psychological, physiological, behavioral, and social functioning. Based on a thorough analysis and synthesis of the published literature (also including most recent meta-analyses), the present paper presents the expressive writing method, its short- and long-term, intra-and interpersonal effects, different situations and conditions in which it has been proven to be effective, the most important mechanisms implied in the process of recovery, advantages, disadvantages, and possible pitfalls of the method, as well as variants of the original technique and future research directions.


1997 ◽  
Vol 17 (03) ◽  
pp. 161-162
Author(s):  
Thomas Hyers

SummaryProblems with unfractionated heparin as an antithrombotic have led to the development of new therapeutic agents. Of these, low molecular weight heparin shows great promise and has led to out-patient therapy of DVT/PE in selected patients. Oral anticoagulants remain the choice for long-term therapy. More cost-effective ways to give oral anticoagulants are needed.


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