scholarly journals A Little Knowledge

2003 ◽  
Vol 125 (10) ◽  
pp. 48-51
Author(s):  
Stuart B. Brown
Keyword(s):  
Power Consumption ◽  
Product Design ◽  
Crack Growth ◽  
Microelectromechanical Systems ◽  
Failure Mechanisms ◽  
Good News ◽  
Natural Evolution ◽  
Initial Product ◽  
Design Concepts

This article explains microelectromechanical systems (MEMS) design concepts that are under investigation for their application in different domains. MEMS provide numerous performance advantages. Miniaturization improves packaging and simplifies installation and maintenance. Power consumption can drop dramatically. Analysis shows that appropriate hermeticity and cleanliness remain a challenge, because sufficient contamination to introduce frequency drift may result from the migration of trace contaminants within a package itself. Many reliability issues apply to different MEMS in diverse ways. Work to date indicates that low-stress, hermetically packaged devices pose little concern about crack growth. The increasing maturity of MEMS and the emphasis on reliability represents good news for the industry, as it reflects the natural evolution from initial product design to fabrication technologies to long-term reliability. Despite current challenges, there is no fundamental constraint to reliability improvements as our knowledge of failure mechanisms and countermeasures increases.

Subcritical Crack Growth and Long-Term Strength in Rock and High-Strength and Ultra Low-Permeability Concrete

2009 ◽  
Vol 58 (6) ◽  
pp. 525-532 ◽  
Author(s):  
Yoshitaka NARA ◽  
Masafumi TAKADA ◽  
Daisuke MORI ◽  
Hitoshi OWADA ◽  
Tetsuro YONEDA ◽  
...  
Keyword(s):  
Crack Growth ◽  
Subcritical Crack Growth ◽  
High Strength ◽  
Low Permeability ◽  
Term Strength

scholarly journals Sustainable Tourism Product Development: An Application of Product Design Concepts

2021 ◽  
Vol 13 (14) ◽  
pp. 7957
Author(s):  
Marco Haid ◽  
Julia N. Albrecht
Keyword(s):  
Product Design ◽  
Sustainable Tourism ◽  
Sustainable Product Design ◽  
Structured Interviews ◽  
Design Concepts ◽  
Design For Sustainability ◽  
Tourism Product ◽  
German Speaking ◽  
Multiple Characteristics ◽  
Sustainable Product

This study examines sustainable tourism products in tourism destinations. Based on concepts of sustainable product design, our study proposes a framework for sustainable tourism products by adapting an existing Design for Sustainability Framework to consider and analyze the characteristics and themes of sustainable (tourism) products as well as their impact and scope. Using a pragmatic qualitative approach, 15 semi-structured interviews with destination managers from the German-speaking Alpine region formed the empirical basis of the study. The results emphasize key themes and multiple characteristics associated with sustainable tourism products in tourist destinations, addressing all sustainability components and design innovation levels. This study is the first to apply existing sustainable product design concepts to destination contexts and discuss their applicability for sustainable tourism products. For practitioners, this study provides support for the development of sustainable tourism products and contributes to a better understanding of the effects and levels of these products as well as sustainability marketing.

scholarly journals Metrics for Measuring Sustainable Product Design Concepts

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3469
Author(s):  
Ji Han ◽  
Pingfei Jiang ◽  
Peter R. N. Childs
Keyword(s):  
Product Design ◽  
End Of Life ◽  
Environmental Impacts ◽  
Conceptual Design ◽  
Design Stage ◽  
Sustainable Product Design ◽  
Early Design ◽  
Design Concepts ◽  
Concept Evaluation ◽  
Sustainable Product

Although products can contribute to ecosystems positively, they can cause negative environmental impacts throughout their life cycles, from obtaining raw material, production, and use, to end of life. It is reported that most negative environmental impacts are decided at early design phases, which suggests that the determination of product sustainability should be considered as early as possible, such as during the conceptual design stage, when it is still possible to modify the design concept. However, most of the existing concept evaluation methods or tools are focused on assessing the feasibility or creativity of the concepts generated, lacking the measurements of sustainability of concepts. The paper explores key factors related to sustainable design with regard to environmental impacts, and describes a set of objective measures of sustainable product design concept evaluation, namely, material, production, use, and end of life. The rationales of the four metrics are discussed, with corresponding measurements. A case study is conducted to demonstrate the use and effectiveness of the metrics for evaluating product design concepts. The paper is the first study to explore the measurement of product design sustainability focusing on the conceptual design stage. It can be used as a guideline to measure the level of sustainability of product design concepts to support designers in developing sustainable products. Most significantly, it urges the considerations of sustainability design aspects at early design phases, and also provides a new research direction in concept evaluation regarding sustainability.

scholarly journals Anticipatory Non-Green-Phenomena Determination for Designing Eco-Design Products

2021 ◽  
Vol 13 (2) ◽  
pp. 621
Author(s):  
Hsin Rau ◽  
Mary Deanne M. Lagapa ◽  
Po-Hsun Chen
Keyword(s):  
Sustainable Development ◽  
Environmental Impact ◽  
Product Design ◽  
Determination Method ◽  
Washing Machine ◽  
Product Failure ◽  
Design Concepts ◽  
The World ◽  
World Business Council

The number of consumers with green awareness have grown these days and as a result they have turned to purchase eco-friendly products. For this reason, this study aims to propose a method for eco-design based on the anticipatory failure determination method to develop eco-design products. By using eco-design concepts adopted from the World Business Council for Sustainable Development, the process will limit the failures and issues related to environmental impact in product design. The proposed method for eco-design product in this study follows the following procedure. First, we analyze product failure. Second, we propose the determination of the non-green phenomenon of the failure. Thirdly, we integrate the intensified non-green phenomenon to generate non-green hypotheses and fourthly, we eliminate each non-green phenomenon hypothesis by introducing the contradiction matrix of TRIZ for obtaining solutions. Finally, we assess alternative eco-design solutions by evaluation. To verify the practicality of the new procedure, a washing machine is used as an example for illustration.

Analysis of thermo-mechanical coupling damage behavior in long-term performance of microelectromechanical systems actuators

2021 ◽  
pp. 105678952110339
Author(s):  
Jiaxing Cheng ◽  
Zhaoxia Li
Keyword(s):  
Damage Mechanics ◽  
Microelectromechanical Systems ◽  
Mechanical Performance ◽  
Damage Model ◽  
Irreversible Damage ◽  
Damage Behavior ◽  
Thermal Actuators ◽  
Long Term Performance ◽  
Term Performance

Effective numerical analysis is significant for the optimal design and reliability evaluation of MEMS, but the complexity of multi-physical field couplings and irreversible damage accumulation in long-term performance make the analysis difficult. In the present paper, the continuum damage mechanics method is used to develop a creep damage model and conduct long-term performance analysis for MEMS thermal actuators with coupled thermo-mechanical damage behavior. The developed damage model can make a connection between the material deterioration due to microstructure changes and the macroscopic responses (the change of thermo-mechanical performance or structure failure). The numerical simulations of coupled thermo-mechanical behavior in long-term performance are implemented using the finite element method, which is validated through comparison with previous literature. The numerical results demonstrate that the proposed damage model and numerical method can provide effective assessment in the long-term performance of MEMS thermal actuators.

A Review of Crack Detection In-Line Inspection Case Studies

2010 ◽  
Author(s):  
Neil Bates ◽  
David Lee ◽  
Clifford Maier
Keyword(s):  
Crack Growth ◽  
Case Studies ◽  
Crack Detection ◽  
Growth Parameters ◽  
Probability Distributions ◽  
Low Frequency ◽  
Probability Of Failure ◽  
Probability Of Detection ◽  
Inspection Data

This paper describes case studies involving crack detection in-line inspections and fitness for service assessments that were performed based on the inspection data. The assessments were used to evaluate the immediate integrity of the pipeline based on the reported features and the long-term integrity of the pipeline based on excavation data and probabilistic SCC and fatigue crack growth simulations. Two different case studies are analyzed, which illustrate how the data from an ultrasonic crack tool inspection was used to assess threats such as low frequency electrical resistance weld seam defects and stress corrosion cracking. Specific issues, such as probability of detection/identification and the length/depth accuracy of the tool, were evaluated to determine the suitability of the tool to accurately classify and size different types of defects. The long term assessment is based on the Monte Carlo method [1], where the material properties, pipeline details, crack growth parameters, and feature dimensions are randomly selected from certain specified probability distributions to determine the probability of failure versus time for the pipeline segment. The distributions of unreported crack-related features from the excavation program are used to distribute unreported features along the pipeline. Simulated crack growth by fatigue, SCC, or a combination of the two is performed until failure by either leak or rupture is predicted. The probability of failure calculation is performed through a number of crack growth simulations for each of the reported and unreported features and tallying their respective remaining lives. The results of the probabilistic analysis were used to determine the most effective and economical means of remediation by identifying areas or crack mechanisms that contribute most to the probability of failure.

SECOND BIRTH OF TROPOSPHERIC COMMUNICATION. PHASED ANTENNA ARRAY COGNITIVE RADIO STATIONS

2020 ◽  
Author(s):  
Л.О. МЫРОВА ◽  
А.В. ШЕВЫРЕВ ◽  
С.А. МУСАЕЛЯН ◽  
И.С. ПОПОВ ◽  
В.А. ВОРОЩАК
Keyword(s):  
Cognitive Radio ◽  
Power Consumption ◽  
Low Power ◽  
Antenna Array ◽  
Radio Stations ◽  
Term Operation ◽  
Hardware Reliability ◽  
Phased Antenna Array ◽  
Technical Solutions

Рассмотрены новые прорывные технические решения по тропосферной связи на основе когнитивных радиостанций с фазированной антенной решеткой (ФАР). Показана возможность повышения (в десятки раз)аппаратурной надежности за счет исключения из состава ТРС мощных передатчиков и применения вместо них маломощных антенных приемопередающих модулей (АППМ),синфазноработающих в составе ФАР. Представлены преимуществами ТРС: возможность длительной работа без технического обслуживания, снижение вдвое энергопотребления, а также глубокая унификация построения ТРС разного класса на основе унифицированных АППМ. New breakthrough technical solutions for tropospheric communication based on cognitive radio stations with a phased antenna array (PAA) are considered. These solutions provide the possibility of increasing the hardware reliability tenfold due to exclusion of powerful transmitters from tropospheric stations (TS) and using instead of them low-power antenna receive-transmitting modules (ARTM), operating in phase as part of the PAA. The advantages of such TSs are shown that enable long-term operation without maintenance, halving power consumption, as well as deep unification of the construction of TSs of different classes based on unified ARTMs.

Creep Crack Growth Prediction of Very Long Term P91 Steel Using Extrapolated Short-Term Uniaxial Creep Data

2013 ◽  
Author(s):  
S. Maleki ◽  
A. Mehmanparast ◽  
K. M. Nikbin
Keyword(s):  
Crack Growth ◽  
Creep Crack Growth ◽  
Life Assessment ◽  
Short Term ◽  
Creep Crack ◽  
Uniaxial Creep ◽  
Laboratory Test Results ◽  
Area Of Concern ◽  
Term Creep

Practical time frames in newly developed steels, and technical and financial restrictions in test durations means that extrapolation of short-term laboratory test results to predict long-term high temperature service component failure is an area of concern when conducting a fitness for service or remaining life assessment. Recent literature presenting uniaxial creep and crack growth tests indicate that some materials show lower failure strains during longer term laboratory tests. The constraint based remaining failure ductility based NSW model crack prediction model has been shown to be capable of predicting upper/lower bounds of creep crack growth in a range of steels when data are obtained from relatively short to medium-term laboratory experiments (< 10,000 hours). This paper compares and analyses the response of the NSW model to predict long term creep crack propagation rates using a wide database of modified 9Cr material over s range of temperatures. The paper employs extrapolation methods of available uniaxial data to make viable conservative predictions of crack growth at high temperatures where at present no data is available.

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