scholarly journals Flexible joints in structural and multibody dynamics

2013 ◽  
Vol 4 (1) ◽  
pp. 65-77 ◽  
Author(s):  
O. A. Bauchau ◽  
S. Han

Abstract. Flexible joints, sometimes called bushing elements or force elements, are found in all structural and multibody dynamics codes. In their simplest form, flexible joints simply consist of sets of three linear and three torsional springs placed between two nodes of the model. For infinitesimal deformations, the selection of the lumped spring constants is an easy task, which can be based on a numerical simulation of the joint or on experimental measurements. If the joint undergoes finite deformations, identification of its stiffness characteristics is not so simple, specially if the joint is itself a complex system. When finite deformations occur, the definition of deformation measures becomes a critical issue. This paper proposes a family of tensorial deformation measures suitable for elastic bodies of finite dimension. These families are generated by two parameters that can be used to modify the constitutive behavior of the joint, while maintaining the tensorial nature of the deformation measures. Numerical results demonstrate the objectivity of the deformations measures, a feature that is not shared by the deformations measures presently used in the literature. The impact of the choice of the two parameters on the constitutive behavior of the flexible joint is also investigated.

Author(s):  
Olivier A. Bauchau ◽  
Leihong Li ◽  
Pierangelo Masarati ◽  
Marco Morandini

Flexible joints, sometimes called bushing elements or force elements, are found in all multibody dynamics codes. In their simplest form, flexible joints simply consist of sets of three linear and three torsional springs placed between two nodes of a multibody system. For infinitesimal deformations, the selection of the lumped spring constants is an easy task, which can be based on a numerical simulation of the joint or on experimental measurements. If the joint undergoes finite deformations, the identification of its stiffness characteristics is not so simple, especially if the joint itself is a complex system. When finite deformations occur, the definition of deformation measures becomes a critical issue. Indeed, for finite deformation, the observed nonlinear behavior of materials is partly due to material characteristics and partly due to kinematics. This paper focuses on the determination of the proper finite deformation measures for elastic bodies of finite dimension. In contrast, classical strain measures, such as the Green–Lagrange or Almansi strains, among many others, characterize finite deformations of infinitesimal elements of a body. It is argued that proper finite deformation measures must be of a tensorial nature, i.e., must present specific invariance characteristics. This requirement is satisfied if and only if the deformation measures are parallel to the eigenvector of the motion tensor.


EDUKASI ◽  
2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Hendra Karianga

Sources of revenue and expenditure of APBD (regional budget) can be allocated to finance the compulsory affairs and optional affairs in the form of programs and activities related to the improvement of public services, job creation, poverty alleviation, improvement of environmental quality, and regional economic growth. The implications of these policies is the need for funds to finance the implementation of the functions, that have become regional authority, is also increasing. In practice, regional financial management still poses a complicated issue because the regional head are reluctant to release pro-people regional budget policy, even implication of regional autonomy is likely to give birth to little kings in region causing losses to state finance and most end up in legal proceedings. This paper discusses the loss of state finance and forms of liability for losses to the state finance. The result of the study can be concluded firstly,  there are still many differences in giving meaning and definition of the loss of state finace and no standard definition of state losses, can cause difficulties. The difficulty there is in an effort to determine the amount of the state finance losses. The calculation of state/regions losses that occur today is simply assessing the suitability of the size of the budget and expenditure without considering profits earned by the community and the impact of the use of budget to the community. Secondly, the liability for losses to the state finance is the fulfillment of the consequences for a person to give or to do something in the regional financial management by giving birth to three forms of liability, namely the Criminal liability, Civil liability, and Administrative liability.Keywords: state finance losses, liability, regional finance.


2017 ◽  
Vol 3 (2) ◽  
pp. 7
Author(s):  
Saida Parvin

Women’s empowerment has been at the centre of research focus for many decades. Extant literature examined the process, outcome and various challenges. Some claimed substantial success, while others contradicted with evidence of failure. But the success remains a matter of debate due to lack of empirical evidence of actual empowerment of women around the world. The current study aimed to address this gap by taking a case study method. The study critically evaluates 20 cases carefully sampled to include representatives from the entire country of Bangladesh. The study demonstrates popular beliefs about microfinance often misguide even the borrowers and they start living in a fabricated feeling of empowerment, facing real challenges to achieve true empowerment in their lives. The impact of this finding is twofold; firstly there is a theoretical contribution, where the definition of women’s empowerment is proposed to be revisited considering findings from these cases. And lastly, the policy makers at governmental and non-governmental organisations, and multinational donor agencies need to revise their assessment tools for funding.


Author(s):  
Yoav Weizman ◽  
Ezra Baruch

Abstract In recent years, two new techniques were introduced for flip chip debug; the Laser Voltage Probing (LVP) technique and Time Resolved Light Emission Microscopy (TRLEM). Both techniques utilize the silicon’s relative transparency to wavelengths longer than the band gap. This inherent wavelength limitation, together with the shrinking dimensions of modern CMOS devices, limit the capabilities of these tools. It is known that the optical resolution limits of the LVP and TRLEM techniques are bounded by the diffraction limit which is ~1um for both tools using standard optics. This limitation was reduced with the addition of immersion lens optics. Nevertheless, even with this improvement, shrinking transistor geometry is leading to increased acquisition time, and the overlapping effect between adjacent nodes remains a critical issue. The resolution limit is an order of magnitude above the device feature densities in the < 90nm era. The scaling down of transistor geometry is leading to the inevitable consequence where more than 50% of the transistors in 90nm process have widths smaller than 0.4um. The acquisition time of such nodes becomes unreasonably long. In order to examine nodes in a dense logic cuicuit, cross talk and convolution effects between neighboring signals also need to be considered. In this paper we will demonstrate the impact that these effects may have on modern design. In order to maintain the debug capability, with the currently available analytical tools for future technologies, conceptual modification of the FA process is required. This process should start on the IC design board where the VLSI designer should be familiar with FA constraints, and thus apply features that will enable enhanced FA capabilities to the circuit in hand during the electrical design or during the physical design stages. The necessity for reliable failure analysis in real-time should dictate that the designer of advanced VLSI blocks incorporates failure analysis constraints among other design rules. The purpose of this research is to supply the scientific basis for the optimal incorporation of design rules for optical probing in the < 90nm gate era. Circuit designers are usually familiar with the nodes in the design which are critical for debug, and the type of measurement (logic or DC level) they require. The designer should enable the measurement of these signals by applying certain circuit and physical constraints. The implementation of these constraints may be done at the cell level, the block level or during the integration. We will discuss the solutions, which should be considered in order to mitigate tool limitations, and also to enable their use for next generation processes.


2021 ◽  
pp. 101053952110260
Author(s):  
Mairead Connolly ◽  
Laura Phung ◽  
Elise Farrington ◽  
Michelle J. L. Scoullar ◽  
Alyce N. Wilson ◽  
...  

Preterm birth and stillbirth are important global perinatal health indicators. Definitions of these indicators can differ between countries, affecting comparability of preterm birth and stillbirth rates across countries. This study aimed to document national-level adherence to World Health Organization (WHO) definitions of preterm birth and stillbirth in the WHO Western Pacific region. A systematic search of government health websites and 4 electronic databases was conducted. Any official report or published study describing the national definition of preterm birth or stillbirth published between 2000 and 2020 was eligible for inclusion. A total of 58 data sources from 21 countries were identified. There was considerable variation in how preterm birth and stillbirth was defined across the region. The most frequently used lower gestational age threshold for viability of preterm birth was 28 weeks gestation (range 20-28 weeks), and stillbirth was most frequently classified from 20 weeks gestation (range 12-28 weeks). High-income countries more frequently used earlier gestational ages for preterm birth and stillbirth compared with low- to middle-income countries. The findings highlight the importance of clear, standardized, internationally comparable definitions for perinatal indicators. Further research is needed to determine the impact on regional preterm birth and stillbirth rates.


Author(s):  
Nadine T. Hillock ◽  
Tracy L. Merlin ◽  
Jonathan Karnon ◽  
John Turnidge ◽  
Jaklin Eliott

Abstract Background The frameworks used by Health Technology Assessment (HTA) agencies for value assessment of medicines aim to optimize healthcare resource allocation. However, they may not be effective at capturing the value of antimicrobial drugs. Objectives To analyze stakeholder perceptions regarding how antimicrobials are assessed for value for reimbursement purposes and how the Australian HTA framework accommodates the unique attributes of antimicrobials in cost-effectiveness evaluation. Methods Eighteen individuals representing the pharmaceutical industry or policy-makers were interviewed. Interviews were transcribed verbatim, coded, and thematically analyzed. Results Key emergent themes were that reimbursement decision-making should consider the antibiotic spectrum when assessing value, risk of shortages, the impact of procurement processes on low-priced comparators, and the need for methodological transparency when antimicrobials are incorporated into the economic evaluation of other treatments. Conclusions Participants agreed that the current HTA framework for antimicrobial value assessment is inadequate to properly inform funding decisions, as the contemporary definition of cost-effectiveness fails to explicitly incorporate the risk of future resistance. Policy-makers were uncertain about how to incorporate future resistance into economic evaluations without a systematic method to capture costs avoided due to good stewardship. Lacking financial reward for the benefits of narrower-spectrum antimicrobials, companies will likely focus on developing broad-spectrum agents with wider potential use. The perceived risks of shortages have influenced the funding of generic antimicrobials in Australia, with policy-makers suggesting a willingness to pay more for assured supply. Although antibiotics often underpin the effectiveness of other medicines, it is unclear how this is incorporated into economic models.


2020 ◽  
Vol 11 (1) ◽  
pp. 38
Author(s):  
Orlando Durán ◽  
Javier Aguilar ◽  
Andrea Capaldo ◽  
Adolfo Arata

Resilience is an intrinsic characteristic of systems. Through it, the capacity of a system to react to the existence of disruptive events is expressed. A series of metrics to represent systems’ resilience have been proposed, however, only one indicator relates the availability of the system to this characteristic. With such a metric, it is possible to relate the topological aspects of a system and the resources available in order to be able to promptly respond to the loss of performance as a result of unexpected events. This work proposes the adaptation and application of such a resilience index to assess the influence of different maintenance strategies and topologies in fleets’ resilience. In addition, an application study considering an actual mining fleet is provided. A set of critical assets was identified and represented using reliability block diagrams. Monte Carlo simulation experiments were conducted and the system availability data were extracted. Resilience indexes were obtained in order to carry out the definition of the best maintenance policies in critical equipment and the assessment of the impact of modifying system redundancies. The main results of this work lead to the overall conclusion that redundancy is an important system attribute in order to improve resiliency along time.


2021 ◽  
Vol 129 ◽  
pp. 107941
Author(s):  
Erica Vassoney ◽  
Andrea Mammoliti Mochet ◽  
Maria Bozzo ◽  
Roberto Maddalena ◽  
Donatella Martinet ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2872
Author(s):  
Miroslav Uhrina ◽  
Anna Holesova ◽  
Juraj Bienik ◽  
Lukas Sevcik

This paper deals with the impact of content on the perceived video quality evaluated using the subjective Absolute Category Rating (ACR) method. The assessment was conducted on eight types of video sequences with diverse content obtained from the SJTU dataset. The sequences were encoded at 5 different constant bitrates in two widely video compression standards H.264/AVC and H.265/HEVC at Full HD and Ultra HD resolutions, which means 160 annotated video sequences were created. The length of Group of Pictures (GOP) was set to half the framerate value, as is typical for video intended for transmission over a noisy communication channel. The evaluation was performed in two laboratories: one situated at the University of Zilina, and the second at the VSB—Technical University in Ostrava. The results acquired in both laboratories reached/showed a high correlation. Notwithstanding the fact that the sequences with low Spatial Information (SI) and Temporal Information (TI) values reached better Mean Opinion Score (MOS) score than the sequences with higher SI and TI values, these two parameters are not sufficient for scene description, and this domain should be the subject of further research. The evaluation results led us to the conclusion that it is unnecessary to use the H.265/HEVC codec for compression of Full HD sequences and the compression efficiency of the H.265 codec by the Ultra HD resolution reaches the compression efficiency of both codecs by the Full HD resolution. This paper also includes the recommendations for minimum bitrate thresholds at which the video sequences at both resolutions retain good and fair subjectively perceived quality.


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