scholarly journals Experimental and Simulation Analysis for the Impact of a Two-Link Chain with Granular Matter

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Eliza A. Banu ◽  
Dan B. Marghitu
Keyword(s):  
Initial Velocity ◽  
Simulation Analysis ◽  
Granular Matter ◽  
Stopping Time ◽  
Kinematic Chain ◽  
Simulation Models ◽  
Resistance Force ◽  
Linear Superposition ◽  
End Point ◽  
The Impact

The resistance force of the granular matter is modeled as a linear superposition of a static (quadratic depth-dependent) resistance force and a dynamic (quadratic velocity-dependent) frictional force. The impact is defined from the moment the end point of the system comes in contact with the granular matter surface until the vertical linear velocity of the end point is zero. The variables of interest are the final depth at the end of the penetration phase and the stopping time. The results for a two-link kinematic chain with two points of contact were compared to the results obtained by applying the resistance force formulation developed to corresponding CAD simulation models. The results revealed that the final displacement increases with initial velocity, while the stopping time decreases. The sensitivity to the initial velocity was studied and an improvement to the resistance force formulated as a result. A series of expressions are proposed for the resistance force coefficients.

scholarly journals Analytical and Experimental Analysis of a Free Link in Contact with a Granular Medium

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Dan B. Marghitu ◽  
Seung Lee
Keyword(s):  
Granular Medium ◽  
Stopping Time ◽  
The Body ◽  
Resistance Force ◽  
Time Interval ◽  
The Moment ◽  
Static Resistance ◽  
The Impact ◽  
Resistance Forces ◽  
Empirical Approaches

In this study, the experimental and the simulation results for a planar free link impacting a granular medium are analyzed. The resistance force of the granular medium on the body from the moment of the impact until the body stops is very important. Horizontal and vertical static resistance forces developed by theoretical and empirical approaches are considered. The penetrating depth of the impacting end of the free link increases with the increase of the initial impacting velocity. We define the stopping time as the time interval from the moment of impact until the vertical velocity of the link end is zero. The stopping time of the end decreases as the initial velocity increases. The faster the end of the link impacts the surface of the granular medium, the sooner it will come to a stop. This phenomenon involves how rapidly a free link strikes the granular medium and how it slows down upon contact.

The Integration of Systems Dynamics and Balanced Scorecards in Strategic Healthcare Policy Simulation Analysis

2010 ◽  
Vol 2 (2) ◽  
pp. 10-34 ◽  
Author(s):  
Mahendran Maliapen ◽  
Alan Gillies
Keyword(s):  
Balanced Scorecard ◽  
Performance Metrics ◽  
Simulation Analysis ◽  
Clinical Performance ◽  
Simulation Models ◽  
Hospital Performance ◽  
Complex Model ◽  
Policy Experimentation ◽  
Balanced Scorecards ◽  
The Impact

This paper uses simulation modelling techniques and presents summarized model outputs using the balanced scorecard approach. The simulation models have been formulated with the use of empirical health, clinical and financial data extracted from clinical data warehouses of a healthcare group. By emphasising the impact of strategic financial and clinical performance measures on healthcare institutions, it is argued that hospitals, in particular, need to re-focus cost-cutting efforts in areas that do not impact clinicians, patient satisfaction or quality of care. The authors have added a real time component to business activity monitoring with the executive dashboards shown as graphs in this paper. This study demonstrates that it is possible to understand health policy interactions and improve hospital performance metrics through evaluation using balanced scorecards and normalized output data. Evidence from this research shows that the hospital executives involved were enthusiastic about the visual interactive interface that provides the transparency needed to isolate policy experimentation from complex model structures that map strategic behaviour.

scholarly journals Simulasi Perubahan Energi Per Bit Dan Derau Terhadap Jumlah Kanal Dan Cakupan WCDMA

2010 ◽  
Vol 2 (2) ◽  
pp. 47
Author(s):  
Alfin Hikmaturokhman ◽  
Hesti Susilawati ◽  
Tantiningrum Niken
Keyword(s):  
No Value ◽  
Simulation Analysis ◽  
Signal To Noise Ratio ◽  
Mobile Station ◽  
Simulation Models ◽  
Signal Strength ◽  
Bit Rate ◽  
Digital Communication System ◽  
Low Sensitivity ◽  
The Impact

Eb/No parameter is the measure of signal to noise ratio for a digital communication system, it is measured at the input to the receiver and is used as the basic measure of how strong the signal is, or in other words Eb/No indicates the fluctuation of received signal strength in the receiver. Eb/No is affected by several factors, such as speed of mobile station, propagation environment and bit rate. The variations of Eb/No value will affect to the number of offered channel and coverage in WCDMA. The impact of the variation of Eb/No value could be recognized in the result of the calculations. The purpose of this research is to build simulation models by using Delphi to view and analyze the influence of Eb/No of total channels and WCDMA coverage. The results from simulation analysis showed that the larger of Eb/No and bit rate used, the number of channels on offer will be smaller and the value of BS is low sensitivity, which means loads of traffic will also offer little that would cause the quality to be better systems and transmit power MS becomes more lower in order to maintain the value of Eb/No to avoid the drop call.  

scholarly journals Underground travel time estimation for macro simulation models, on the example of the first line in Warsaw

2014 ◽  
Vol 13 (4) ◽  
pp. 067-074
Author(s):  
Marek Bauer
Keyword(s):  
Travel Time ◽  
Stopping Time ◽  
Time Estimation ◽  
Simulation Models ◽  
Stopping Times ◽  
Travel Time Estimation ◽  
Travel Time Prediction ◽  
Running Time ◽  
Average Running Time ◽  
The Impact

In this paper, the author’s model of underground travel time prediction was presented. The structure of the model can be used to estimate the travel time of any underground line in the planning phase. The model takes into account the length and the variability of running time between stations and stopping time at these stations. Partial models of average running time depending on the length of the sections – for six periods of the working day, developed on the basis of measurements on the first underground line in Warsaw were presented. Similar models for the estimation of the standard deviation of running time were also presented. Stopping times for three types of stations, varying in terms of the average stopping time and location of the station in relation to the city center were estimated. Paper presents also a practical example of the use of the model: evaluation of the impact of additional stations on the travel time on the underground line in Warsaw.

Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality

2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira
Keyword(s):  
Amorphous Silicon ◽  
High Throughput Screening ◽  
Simulation Analysis ◽  
Low Cost ◽  
Deposition Process ◽  
Large Area ◽  
Sidewall Roughness ◽  
Sensing Applications ◽  
Fabrication Defects ◽  
The Impact

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.

Graves' disease and radioiodine therapy

2008 ◽  
Vol 47 (04) ◽  
pp. 153-166 ◽  
Author(s):  
I. Weber ◽  
W. Eschner ◽  
F. Sudbrock ◽  
M. Schmidt ◽  
M. Dietlein ◽  
...  
Keyword(s):  
Success Rate ◽  
Thyroid Function ◽  
Therapeutic Dose ◽  
Radioiodine Therapy ◽  
Antithyroid Drugs ◽  
Graves Disease ◽  
Inclusion Criteria ◽  
End Point ◽  
Point Measure ◽  
The Impact

SummaryAim: This study was performed to analyse the impact of the choice of antithyroid drugs (ATD) on the outcome of ablative radioiodine therapy (RIT) in patients with Graves' disease. Patients, material, methods: A total of 571 consecutive patients were observed for 12 months after RIT between July 2001 and June 2004. Inclusion criteria were the confirmed diagnosis of Graves' disease, compensation of hyperthyroidism and withdrawal of ATD two days before preliminary radioiodine-testing and RIT. The intended dose of 250 Gy was calculated from the results of the radioiodine test and the therapeutically achieved dose was measured by serial uptake measurements. The end-point measure was thyroid function 12 months after RIT; success was defined as elimination of hyperthyroidism. The pretreatment ATD was retrospectively correlated with the results achieved. Results: Relief from hyperthyroidism was achieved in 96 % of patients. 472 patients were treated with carbimazole or methimazole (CMI) and 61 with propylthiouracil (PTU). 38 patients had no thyrostatic drugs (ND) prior to RIT. The success rate was equal in all groups (CMI 451/472; PTU 61/61; ND 37/38; p=0.22). Conclusion: Thyrostatic treatment with PTU achieves excellent results in ablative RIT, using an accurate dosimetric approach with an achieved post-therapeutic dose of more than 200 Gy.

scholarly journals Micro-mechanical investigation of railway ballast behavior under cyclic loading in a box test using DEM: effects of elastic layers and ballast types

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kumar ◽  
Bettina Suhr ◽  
Stefan Marschnig ◽  
Peter Dietmaier ◽  
Christof Marte ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Early Stage ◽  
Damage Model ◽  
Simulation Models ◽  
Railway Track ◽  
Maintenance Cost ◽  
Particle Movement ◽  
Railway Ballast ◽  
Elastic Layers ◽  
The Impact

Abstract Ballasted tracks are the commonly used railway track systems with constant demands for reducing maintenance cost and improved performance. Elastic layers are increasingly used for improving ballasted tracks. In order to better understand the effects of elastic layers, physical understanding at the ballast particle level is crucial. Here, discrete element method (DEM) is used to investigate the effects of elastic layers – under sleeper pad ($$\text {USP}$$USP) at the sleeper/ballast interface and under ballast mat ($$\text {UBM}$$UBM) at the ballast/bottom interface – on micro-mechanical behavior of railway ballast. In the DEM model, the Conical Damage Model (CDM) is used for contact modelling. This model was calibrated in Suhr et al. (Granul Matter 20(4):70, 2018) for the simulation of two different types of ballast. The CDM model accounts for particle edge breakage, which is an important phenomenon especially at the early stage of a tamping cycle, and thus essential, when investigating the impact of elastic layers in the ballast bed. DEM results confirm that during cyclic loading, $$\text {USP}$$USP reduces the edge breakage at the sleeper/ballast interface. On the other hand, $$\text {UBM}$$UBM shows higher particle movement throughout the ballast bed. Both the edge breakage and particle movement in the ballast bed are found to influence the sleeper settlement. Micro-mechanical investigations show that the force chain in deeper regions of the ballast bed is less affected by $$\text {USP}$$USP for the two types of ballast. Conversely, dense lateral forces near to the box bottom were seen with $$\text {UBM}$$UBM. The findings are in good (qualitative) agreement with the experimental observations. Thus, DEM simulations can aid to better understand the micro-macro phenomena for railway ballast. This can help to improve the track components and track design based on simulation models taking into account the physical behavior of ballast. Graphical Abstract

P1574EFFECTS OF BRAZILIAN GREEN PROPOLIS EXTRACT (EPP-AF) ON INFLAMMATION IN HEMODIALYSIS PATIENTS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Marcelo Silveira ◽  
Flavio Teles ◽  
Erica Melo ◽  
Valeria Borges ◽  
Filipe Miranda ◽  
...  
Keyword(s):  
Control Period ◽  
Prospective Trial ◽  
Hemodialysis Patients ◽  
Intermittent Hemodialysis ◽  
Plant Materials ◽  
Propolis Extract ◽  
End Point ◽  
Number Of Patients ◽  
The Impact ◽  
Brazilian Green Propolis

Abstract Background and Aims End-stage chronic kidney disease is associated with the condition of chronic inflammation, impacting increased cardiovascular mortality in this specific population. Patients on hemodialysis are known to be predisposed to several factors that predispose to inflammation: dialysis membranes, central venous catheters, oxidative stress, fluid overload, sodium overload, uraemic toxins. Propolis, a natural resin produced by bees from plant materials, has anti-inflammatory, immunomodulatory, and anti-oxidant properties. The aim of this study was to evaluate the impact of Brazilian green propolis extract on inflammation in hemodialysis patients. Here we present preliminary results of the trial NCT04072341. Method We performed a prospective trial, open-label 9-week crossover study examining the effect of Brazilian green propolis (250mg/day, in capsules) on inflammation in hemodialysis patients. We included patients over 18 years, under intermittent hemodialysis (thrice per week), on hemodialysis for at least 1 month and until now 37 patients were included. We excluded pregnant women, cancer carried and patients who developed infection or underwent any surgical procedure during the study period. Each period was 4 weeks in duration with a 1-week washout period in between. The primary end point was change in serum level of high-sensitivity c-reactive protein (HsCRP). Secondary end point evaluated the safety of propolis use in hemodialysis patients. Results Their mean age was 58.6 ± 15.2 years (mean ± SD), and 22 (59.4%) were men. The proportion of patients with hypertension was 14 (37.8%) and diabetes was 9 (24.3%). The number of patients using arteriovenous fistula were 26 (70.2%). The HsCRP presented (mean ± SE) 5.31 ± 1.02 mg/L at baseline, 4.26 ± 0.76 mg/L after propolis period and 4.56 ± 1.32 mg/L in control period, p = 0.0042. Safety parameters were analyzed such as amylase, aspartate aminotransferase (AST) and creatine phosphokinase (CPK); there was no difference between them before and after the use of propolis. None of the participants reported any adverse effects or allergic reactions during the treatment. Conclusion Patients on hemodialysis have an increased inflammatory state. For the best of our knowledge it was the first clinical trial who demonstrated the safety of propolis in hemodialysis patients. Brazilian green propolis demonstrated a tendency to reduce inflammation in these patients.

scholarly journals Assessing asset monitoring levels for maintenance operations

2015 ◽  
Vol 26 (5) ◽  
pp. 632-659 ◽  
Author(s):  
Abdullah A Alabdulkarim ◽  
Peter Ball ◽  
Ashutosh Tiwari
Keyword(s):  
Asset Management ◽  
Business Models ◽  
Discrete Event ◽  
Dynamic Modelling ◽  
Simulation Models ◽  
Content Type ◽  
Event Simulation ◽  
Product Service ◽  
Asset Monitoring ◽  
The Impact

Purpose – Asset management has recently gained significance due to emerging business models such as Product Service Systems where the sale of asset use, rather than the sale of the asset itself, is applied. This leaves the responsibility of the maintenance tasks to fall on the shoulders of the manufacturer/supplier to provide high asset availability. The use of asset monitoring assists in providing high availability but the level of monitoring and maintenance needs to be assessed for cost effectiveness. There is a lack of available tools and understanding of their value in assessing monitoring levels. The paper aims to discuss these issues. Design/methodology/approach – This research aims to develop a dynamic modelling approach using Discrete Event Simulation (DES) to assess such maintenance systems in order to provide a better understanding of the behaviour of complex maintenance operations. Interviews were conducted and literature was analysed to gather modelling requirements. Generic models were created, followed by simulation models, to examine how maintenance operation systems behave regarding different levels of asset monitoring. Findings – This research indicates that DES discerns varying levels of complexity of maintenance operations but that more sophisticated asset monitoring levels will not necessarily result in a higher asset performance. The paper shows that it is possible to assess the impact of monitoring levels as well as make other changes to system operation that may be more or less effective. Practical implications – The proposed tool supports the maintenance operations decision makers to select the appropriate asset monitoring level that suits their operational needs. Originality/value – A novel DES approach was developed to assess asset monitoring levels for maintenance operations. In applying this quantitative approach, it was demonstrated that higher asset monitoring levels do not necessarily result in higher asset availability. The work provides a means of evaluating the constraints in the system that an asset is part of rather than focusing on the asset in isolation.

scholarly journals USMED: broadening the impact of simulation analysis methodology

2005 ◽  
Author(s):  
R.R. Barton ◽  
L.W. Schruben ◽  
J.C. Ford ◽  
D. Hopkins ◽  
D. Goldsman ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Analysis Methodology ◽  
The Impact
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