Impact Dynamics of Single-Layered Graphene Sheets in Multibody Framework Using Nonlocal-Based-ANCF Modeling

2019 ◽  
Vol 19 (09) ◽  
pp. 1950099
Author(s):  
Qingtao Wang ◽  
Yang Zhang ◽  
Qixin Zhu ◽  
Zhaojun Pang
Keyword(s):  
Pair Potential ◽  
Gold Atom ◽  
Nonlocal Elasticity Theory ◽  
Nonlocal Theory ◽  
Impact Dynamics ◽  
Graphene Sheets ◽  
Dynamic Simulations ◽  
Definition Of ◽  
Vdw Force ◽  
The Impact

A new nonlinear model based on the absolute nodal coordinate formulation (ANCF) and the nonlocal elasticity theory is proposed to investigate the single-layered graphene sheets (SLGSs) impacted by nanoparticles. The geometrical definition of SLGSs is described by using the ANCF thin plate element, and the strain energy is expressed by using the nonlocal theory. The Lennard–Jones pair potential is adopted to model the van der Waals (vdW) force between SLGSs and nanoparticles. The impact dynamics of the system is simulated in multibody framework by using the generalized-alpha numerical integration method. The impact response of the gold atom–SLGSs system is simulated to validate the performance of the proposed model. Three impact dynamic simulations are conducted to investigate the influence of nanoparticles on the impact dynamics of SLGSs. The results show that the coupling of SLGSs vibration and vdW force led to the amplitude inconsistence of [Formula: see text]-position for nanoparticles.

Nonlinear Large Deformation of Graphene Sheets Using a Nonlocal-Based ANCF Method

2019 ◽  
Vol 11 (04) ◽  
pp. 1950037 ◽  
Author(s):  
Qingtao Wang ◽  
Zhen Zhao ◽  
Yang Zhang ◽  
Zhaojun Pang ◽  
Fuzhou Niu
Keyword(s):  
Large Deformation ◽  
Nonlocal Elasticity Theory ◽  
Nonlocal Theory ◽  
Elastic Force ◽  
Graphene Sheets ◽  
Deformation Problem ◽  
Proposed Model ◽  
Large Deformation Problem ◽  
Loading Modes ◽  
Definition Of

A novel nonlinear model of single-layered graphene sheets (SLGSs) subject to large deformation is proposed using the absolute nodal coordinate formulation (ANCF) and the nonlocal elasticity theory. The geometrical definition of SLGSs is described by ANCF thin plate element while the strain energy is expressed by nonlocal theory. Then, the formulation of elastic force and the Jacobian of the elastic force is derived. We verify the proposed model by comparing the results with other published results and conduct corresponding numerical case study to clarify the influence of boundary conditions (BCs), nonlocal parameters, side length and aspect ratio. Large deformation problem of SLGSs with several BCs and different loading modes are simulated to study the mechanical nonlinearity of the SLGSs.

The nonlocal parameter for three-dimensional nonlocal elasticity analyses of square graphene sheets: An exact buckling analysis

2021 ◽  
pp. 239779142110298
Author(s):  
Abusaleh Naderi
Keyword(s):  
Nonlocal Elasticity ◽  
Nonlocal Parameter ◽  
Three Dimensional ◽  
Nonlocal Elasticity Theory ◽  
Graphene Sheets ◽  
Two Dimensional ◽  
Dynamic Simulations ◽  
Buckling Stress ◽  
Simplifying Assumptions ◽  
Comparison Of The Results

This paper studies buckling problem of square nano-plates under uniform biaxial pressure through using three-dimensional nonlocal elasticity theory. Equations of stability are solved analytically for square nano-plates with simple supports using a Navier-type method. Critical buckling stress is presented for nano square plates with different thickness-length and nonlocal parameter-length ratios. The critical buckling stress is also reported using different local (classical) and nonlocal two-dimensional plate theories constructed essentially based on some simplifying assumptions. Comparison of the results of two-dimensional and three-dimensional theories for both local and nonlocal cases shows that the nonlocal two-dimensional plate theories are not as accurate as the local two-dimensional ones. This issue however reveals importance of the nonlocal three-dimensional solutions. Finally, through comparison of the numerical results with those obtained from molecular dynamic simulations, the value of the nonlocal parameter is calibrated for square graphene sheets. This parameter can be also used for the other nonlocal three-dimensional mechanical analyses of square graphene sheets to find accurate solutions.

PERTANGGUNGJAWABAN KERUGIAN NEGARA DALAM PENGELOLAAN KEUANGAN DAERAH

EDUKASI ◽  
2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Hendra Karianga
Keyword(s):  
Financial Management ◽  
Criminal Liability ◽  
The State ◽  
Legal Proceedings ◽  
Regional Finance ◽  
Regional Budget ◽  
State Finance ◽  
Budget Policy ◽  
Definition Of ◽  
The Impact

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.

Empowering Women Entrepreneurs Through Microfinance - A Case of Rural Bangladesh

2017 ◽  
Vol 3 (2) ◽  
pp. 7
Author(s):  
Saida Parvin
Keyword(s):  
Women's Empowerment ◽  
Assessment Tools ◽  
Women’S Empowerment ◽  
Case Study Method ◽  
Policy Makers ◽  
Theoretical Contribution ◽  
Donor Agencies ◽  
Definition Of ◽  
The Impact

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.

Simulation of the Impact of Higher Ammonia Recycle Loads Caused by Upgrading Anaerobic Sludge Digesters

2005 ◽  
Vol 40 (4) ◽  
pp. 491-499 ◽  
Author(s):  
Jeremy T. Kraemer ◽  
David M. Bagley
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Anaerobic Sludge ◽  
Content Increase ◽  
Limited Information ◽  
Dynamic Simulations ◽  
Treatment Train ◽  
Temperature Liquid ◽  
The Impact

Abstract Upgrading conventional single-stage mesophilic anaerobic digestion to an advanced digestion technology can increase sludge stability, reduce pathogen content, increase biogas production, and also increase ammonia concentrations recycled back to the liquid treatment train. Limited information is available to assess whether the higher ammonia recycle loads from an anaerobic sludge digestion upgrade would lead to higher discharge effluent ammonia concentrations. Biowin, a commercially available wastewater treatment plant simulation package, was used to predict the effects of anaerobic digestion upgrades on the liquid train performance, especially effluent ammonia concentrations. A factorial analysis indicated that the influent total Kjeldahl nitrogen (TKN) and influent alkalinity each had a 50-fold larger influence on the effluent NH3 concentration than either the ambient temperature, liquid train SRT or anaerobic digestion efficiency. Dynamic simulations indicated that the diurnal variation in effluent NH3 concentration was 9 times higher than the increase due to higher digester VSR. Higher recycle NH3 loads caused by upgrades to advanced digestion techniques can likely be adequately managed by scheduling dewatering to coincide with periods of low influent TKN load and ensuring sufficient alkalinity for nitrification.

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

Defining Preterm Birth and Stillbirth in the Western Pacific: A Systematic Review

2021 ◽  
pp. 101053952110260
Author(s):  
Mairead Connolly ◽  
Laura Phung ◽  
Elise Farrington ◽  
Michelle J. L. Scoullar ◽  
Alyce N. Wilson ◽  
...  
Keyword(s):  
Preterm Birth ◽  
National Level ◽  
Health Indicators ◽  
Western Pacific ◽  
World Health ◽  
Middle Income ◽  
Middle Income Countries ◽  
Definition Of ◽  
Health Organization ◽  
The Impact

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.

Value assessment of antimicrobials and the implications for development, access, and funding of effective treatments: Australian stakeholder perspective

2020 ◽  
pp. 1-7
Author(s):  
Nadine T. Hillock ◽  
Tracy L. Merlin ◽  
Jonathan Karnon ◽  
John Turnidge ◽  
Jaklin Eliott
Keyword(s):  
Cost Effectiveness ◽  
Healthcare Resource ◽  
Economic Evaluations ◽  
Value Assessment ◽  
Antimicrobial Drugs ◽  
Policy Makers ◽  
Stakeholder Perspective ◽  
Definition Of ◽  
The Impact ◽  
Potential Use

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.

scholarly journals Fleet Resilience: Evaluating Maintenance Strategies in Critical Equipment

2020 ◽  
Vol 11 (1) ◽  
pp. 38
Author(s):  
Orlando Durán ◽  
Javier Aguilar ◽  
Andrea Capaldo ◽  
Adolfo Arata
Keyword(s):  
Application Study ◽  
System Availability ◽  
Maintenance Strategies ◽  
Resilience Index ◽  
Reliability Block Diagrams ◽  
Maintenance Policies ◽  
Definition Of ◽  
The Impact ◽  
Important System ◽  
Intrinsic Characteristic

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.

Sign in / Sign up

Export Citation Format

Share Document