scholarly journals Verification of Fatigue Damage and Prognosis Related to Degradation of Polymer-Ceramic

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5147
Author(s):  
Piotr Kosiński ◽  
Piotr Żach
Keyword(s):  
Polyvinyl Butyral ◽  
Road Accidents ◽  
The Finite Element Method ◽  
External Temperature ◽  
Fem Simulations ◽  
Head Injury Criterion ◽  
Autumn And Winter ◽  
The Impact ◽  
Temperature Heating ◽  
Twofold Decrease

Statistically, road accidents involving pedestrians occur in the autumn and winter months, when outdoor temperatures reach −30 °C. The research presented in this paper investigates the impact of a pedestrian’s head on laminated windscreen, taking into account the effects of external temperature, heating of the windscreen from the inside, and fatigue of the glass. The automotive laminated windscreen under study is made from two layers of glass and a Polyvinyl Butyral (PVB) resin bonding them together. PVB significantly changes its properties with temperature. The Finite Element Method (FEM) simulations of a pedestrian’s head hitting the windscreen of an Opel Astra II at <−30 °C, +20 °C> were performed. The obtained Head Injury Criterion (HIC) results revealed an almost twofold decrease in safety between +20 °C and −20 °C. The same test was then performed taking into account the heating of the windscreen from the inside and the fatigue of the glass layers. Surprisingly, the highest HIC value of all the cases studied was obtained at −30 °C and heating the windscreen. The nature of safety changes with temperature variation is different for the cases of heating, non-heating, and fatigue of glass layers. Glass fatigue increases pedestrian safety throughout the temperature range analysed.

Static grid carbon factors – Can we do better?

2021 ◽  
pp. 014362442199196
Author(s):  
Jamie Risner ◽  
Anna Sutherland
Keyword(s):  
Carbon Emissions ◽  
Regional Analysis ◽  
Electricity Consumption ◽  
Carbon Intensity ◽  
External Temperature ◽  
Building Regulations ◽  
Calculation Methodology ◽  
Alternative Methodology ◽  
The Uk ◽  
The Impact

The average carbon intensity (gCO2e/kWh) of electricity provided by the UK National Grid is decreasing and becoming more time variable. This paper reviews the impact on energy calculations of using various levels of data resolution (half hourly, daily, monthly and annual) and of moving to region specific data. This analysis is in two parts, one focused on the potential impact on Part L assessments and the other on reported carbon emissions for existing buildings. Analysis demonstrated that an increase in calculated emissions of up to 12% is possible when using an emissions calculation methodology employing higher resolution grid carbon intensity data. Regional analysis indicated an even larger calculation discrepancy, with some regions annual emissions increasing by a factor of ten as compared to other regions. This paper proposes a path forward for the industry to improve the accuracy of analysis by using better data sources. The proposed change in calculation methodology is analogous to moving from using an annual average external temperature to using a CIBSE weather profile for a specific city or using a future weather file. Practical application: This paper aims to quantify the inaccuracy of a calculation methodology in common use in the industry and key to building regulations (specifically Building Regulations Part L – Conservation of Fuel and Power) – translating electricity consumption into carbon emissions. It proposes an alternative methodology which improves the accuracy of the calculation based on improved data inputs.

scholarly journals The effect of the outlet angle β2 on the thermomechanical behavior of a centrifugal compressor blade

2020 ◽  
Vol 29 (1) ◽  
pp. 1-8
Author(s):  
Ahmed Allali ◽  
Sadia Belbachir ◽  
Ahmed Alami ◽  
Belhadj Boucham ◽  
Abdelkader Lousdad
Keyword(s):  
Mechanical Behavior ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Complex Form ◽  
Compressor Blade ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Mechanical Fatigue ◽  
Outlet Angle ◽  
The Impact

AbstractThe objective of this work lies in the three-dimensional study of the thermo mechanical behavior of a blade of a centrifugal compressor. Numerical modeling is performed on the computational code "ABAQUS" based on the finite element method. The aim is to study the impact of the change of types of blades, which are defined as a function of wheel output angle β2, on the stress fields and displacements coupled with the variation of the temperature.This coupling defines in a realistic way the thermo mechanical behavior of the blade where one can note the important concentrations of stresses and displacements in the different zones of its complex form as well as the effects at the edges. It will then be possible to prevent damage and cracks in the blades of the centrifugal compressor leading to its failure which can be caused by the thermal or mechanical fatigue of the material with which the wheel is manufactured.

scholarly journals Air pollution and out-of-hospital cardiac arrest risk

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
L Moderato ◽  
D Lazzeroni ◽  
A Biagi ◽  
T Spezzano ◽  
B Matrone ◽  
...  
Keyword(s):  
Air Pollution ◽  
Cardiac Arrest ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
External Temperature ◽  
Pm 2.5 ◽  
Pm10 And Pm2.5 ◽  
Short Term Exposure ◽  
The Impact ◽  
Hospital Cardiac Arrest

Abstract Introduction Out-of-hospital cardiac arrest (OHCA) is a leading cause of death worldwide; it accounts for up to 50% of all cardiovascular deaths.It is well established that ambient air pollution triggers fatal and non-fatal cardiovascular events. However, the impact of air pollution on OHCA is still controversial. The objective of this study was to investigate the impact of short-term exposure to outdoor air pollutants on the incidence of OHCA in the urban area of Piacenza, Italy, one of the most polluted area in Europe. Methods From 01/01/2010 to 31/12/2017 day-by-day PM10 and PM2.5 levels, as well as climatic data, were extracted from Environmental Protection Agency (ARPA) local monitoring stations. OHCA were extracted from the prospective registry of Community-based automated external defibrillator Cardiac arrest “Progetto Vita”. OHCA data were included: audio recordings, event information and ECG tracings. Logistic regression analysis was used to estimate the association between the risk of OHC, expressed as odds ratios (OR), associated with the PM10 and PM2.5 levels. Results Mean PM10 levels were 33±29 μg/m3 and the safety threshold (50 μg/m3) recommended by both WHO and Italian legislation has been exceeded for 535 days (17.5%). Mean PM 5 levels were 33±29 μg/m3. During the follow-up period, 880 OHCA were recorded on 750 days; the remaining 2174 days without OHCA were used as control days. Mean age of OHCA patients was 76±15 years; male gender was prevalent (55% male vs 45% female; &lt;0.001). Concentration of PM10 and PM 2.5 were significantly higher on days with the occurrence of OHCA (PM10 levels: 37.7±22 μg/m3 vs 32.7±19 μg/m3; p&lt;0.001; PM 2.5 levels: 26±16 vs 22±15 p&lt;0.001). Risk of OHCA was significantly increased with the progressive increase of PM10 (OR: 1.009, 95% CI 1.004–1.015; p&lt;0.001) and PM2.5 levels (OR 1.012, 95% CI 1.007–1.017; p&lt;0.001). Interestingly, the above mentioned results remain independent even when correct for external temperature or season (PM 2.5 levels: p=0.01 – PM 10 levels: p=0.002), Moreover, dividing PM10 values in quintiles, a 1.9 fold higher risk of cardiac arrest has been showed in the highest quintile (Highest quintile cut-off: &lt;48μg/m3) Conclusions In large cohort of patients from a high pollution area, both PM10 and PM2.5 levels are associated with the risk of Out-of-hospital cardiac arrest. PM10 and PM2.5 levels and risk of OHCA Funding Acknowledgement Type of funding source: None

scholarly journals Manufacturing, Characterisation and Mechanical Analysis of Polyacrylonitrile Membranes

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2378
Author(s):  
Mertol Tüfekci ◽  
Sevgi Güneş Durak ◽  
İnci Pir ◽  
Türkan Ormancı Acar ◽  
Güler Türkoğlu Demirkol ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Main Idea ◽  
Mechanical Analysis ◽  
Operating Conditions ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Load Carrying ◽  
The Impact ◽  
Static Behaviour ◽  
Modelling Process

To investigate the effect of polyvinylpyrrolidone (PVP) addition and consequently porosity, two different sets of membranes are manufactured, since PVP is a widely used poring agent which has an impact on the mechanical properties of the membrane material. The first set (PAN 1) includes polyacrylonitrile (PAN) and the necessary solvent while the second set (PAN 2) is made of PAN and PVP. These membranes are put through several characterisation processes including tensile testing. The obtained data are used to model the static behaviour of the membranes with different geometries but similar loading and boundary conditions that represent their operating conditions. This modelling process is undertaken by using the finite element method. The main idea is to investigate how geometry affects the load-carrying capacity of the membranes. Alongside membrane modelling, their materials are modelled with representative elements with hexagonal and rectangular pore arrays (RE) to understand the impact of porosity on the mechanical properties. Exploring the results, the best geometry is found as the elliptic membrane with the aspect ratio 4 and the better RE as the hexagonal array which can predict the elastic properties with an approximate error of 12%.

Deceleration of sliding motorcycles (mainly scooters) in accident reconstructions

2017 ◽  
Vol 232 (7) ◽  
pp. 866-876 ◽  
Author(s):  
Carlo Cialdai ◽  
Dario Vangi ◽  
Antonio Virga
Keyword(s):  
Urban Areas ◽  
Test Session ◽  
Road Accidents ◽  
Factors Affecting ◽  
Different Types ◽  
Energy Dissipated ◽  
Comparison Of The Results ◽  
Two Wheeler ◽  
The Impact ◽  
Good Agreement

This paper presents an analysis of the situation in which a two-wheeler (i.e. a motorcycle, where the term motorcycles includes scooters) falls over to the side and then successively slides; this typically occurs in road accidents involving this type of vehicle. Knowing the deceleration rate of the sliding phase allows the kinetic energy dissipated and the speed of the motorcycle just before the fall to the ground to be calculated. These parameters are very important in the analysis and reconstruction of accidents. The work presented in this paper was developed in two experimental test sessions on fully faired motorcycles which are mainly of the scooter type and widely used in urban areas. In the first session, sliding tests were carried out, with the speed in the range 10–50 km/h, on three different types of road surface. Analysis of the evidence allowed the dissipative main phases of motion of the motorcycle (the impact with the ground, the rebounds and the stabilized swiping) to be identified and some factors affecting the phenomenon to be studied. The coefficient of average deceleration was calculated using two typical equations. The second test session consisted of drag tests. In these tests, the motorcycle, which had previously laid on its side, was dragged for a few metres at a constant speed of about 20 km/h, while the drag force was measured. A comparison of the results obtained in these tests with those obtained in the sliding tests yielded very good agreement in the coefficients of deceleration.

Road barriers: modern solutions for improving traffic safety

2021 ◽  
pp. 43-48
Author(s):  
Keyword(s):  
Traffic Safety ◽  
Traffic Accident ◽  
Preventive Measures ◽  
Mechanical Damage ◽  
Road Accidents ◽  
Road Users ◽  
Urgent Task ◽  
The Moment ◽  
Energy Absorbing ◽  
The Impact

Improving the system of preventive measures aimed at reducing the severity of the consequences of road accidents is an urgent task. Road deaths are constantly increasing and there is a need for a comprehensive approach to creating safe road conditions. The purpose of this study is to analyze the promising designs of road barriers designed to prevent uncontrolled exit of vehicles from the roadway of the highway and to develop the design of energy-absorbing fencing. Barrier barriers must not only be safe for road users, but must also ensure their safety, as well as preserve the elements after hitting the fence. Analytical studies have shown that in order to reduce mechanical damage to vehicles and reduce the severity of injuries to the driver and passengers, it is necessary to develop a road fence design that allows you to extinguish the impact energy at the moment of contact between the car and the fence. Keywords: fencing, barrier, safety, traffic accident

scholarly journals Biomarkers responses in fish (Atherinella brasiliensis) of paranaguá bay, southern Brazil, for assessment of pollutant effects

2013 ◽  
Vol 61 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Ciro Alberto de Oliveira Ribeiro ◽  
Alberto Katsumiti ◽  
Patrícia França ◽  
Jocieli Maschio ◽  
Eliandra Zandoná ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Protected Areas ◽  
Aquatic Organisms ◽  
Southern Brazil ◽  
Paranaguá Bay ◽  
Fuel Oils ◽  
Polycyclic Aromatic ◽  
Biochemical Genetic ◽  
Autumn And Winter ◽  
The Impact

Paranaguá bay is a complex estuary located in southern Brazil containing three protected areas listed by UNESCO. Historically, the estuary has been affected by urban, industrial, agricultural and harbor activities, and occasional accidents. Specifically, the explosion of the Chilean ship Vicuña in December 2004 spilled methanol and crude and fuel oils which affected both protected and non-protected areas. The present study sought to investigate the pollution threat to aquatic organisms in order to evaluate the potential effects of pollutants. One hundred and twenty adult fish Atherinella brasiliensis were collected from different sites within Paranaguá estuary, including the harbor and open ocean, during summer, autumn and winter of 2005. Among the biomarkers, the somatic index, chemical analysis of bile, biochemical, genetic and morphological parameters were considered. Chemical analysis of bile showed a continuous bioavailability of polycyclic aromatic hydrocarbons (PAHs) according to proximity to the harbor site. The histopathological findings have demonstrated aconsiderable incidence of severe pathologies in the liver and gills, corroborated by biochemical disturbances and genetic damage. These findings indicate that more studies are necessary to evaluate both water quality and fish health so as to permit a better analysis of the impact of pollution in Paranaguá estuary.

scholarly journals Safety and reliability of the personal bus carriages in integrated municipal system of traffic and public transport management - analysis of literature

2018 ◽  
Vol 19 (12) ◽  
pp. 246-251
Author(s):  
Paweł Woś ◽  
Jacek Michalski
Keyword(s):  
Public Transport ◽  
Road Safety ◽  
Road Transport ◽  
The European Union ◽  
Road Accidents ◽  
Safety And Reliability ◽  
Key Indicators ◽  
The Impact ◽  
The City ◽  
The Eu

The article analyzes the city's logistics development strategies and its public transport, especially bus traffic. Statistical analysis of all road transport in the European Union (EU) has been carried out. The most important reasons for the tragic road accidents in Poland have been mixed up. Key elements of active safety and passive safety of buses and road safety were analyzed. Characterized key indicators of road safety in the EU and the probability of bus incidents. The impact on the ecology of the city of road transport was analyzed in terms of the significance of exhaust emissions of various bus designs and emissions of other pollutants.

The Performance of Steel Beam during the Cooling Phase and the Impact of Fire Parameters

2013 ◽  
Vol 404 ◽  
pp. 232-236
Author(s):  
Xiu Ying Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Solid Model ◽  
Steel Beam ◽  
Uniform Load ◽  
Cooling Process ◽  
Internal Forces ◽  
Cooling Phase ◽  
The Impact ◽  
Temperature Heating

In order to study the performance of steel beam in the cooling process, a series of numerical analysis has been carried out in this paper. The solid model of the beam was established firstly using finite element method, the beam was heated and cooled gradually under the certain uniform load, then the internal forces and deformation of the beam were analyzed in the whole fire process. Based on this, the parameters of the highest temperature, heating rate and the cooling rate were changed, and their affect on the beam performance was studied by comparing.

scholarly journals Numerical Modelling of Soil Arching in a Shallow Backfill Layer

2015 ◽  
Vol 15 (4) ◽  
pp. 127-137 ◽  
Author(s):  
Waldemar St. Szajna
Keyword(s):  
Internal Friction ◽  
Flexible Structures ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Plasticity Condition ◽  
Flow Rule ◽  
The Finite Element Method ◽  
Soil Arching ◽  
Plain Strain ◽  
The Impact

Abstract The paper presents the application of the finite element method into the modelling of soil arching. The phenomenon plays fundamental role in soil-shell flexible structures behaviour. To evaluate the influence of arching on a pressure reduction, a plain strain trapdoor under a shallow layer of backfill was simulated. The Coulomb-Mohr plasticity condition and the nonassociated flow rule were used for the soil model. The research examines the impact of the internal friction angle and the influence of the backfill layer thickness on the value of soil arching. The carried out analyses indicate that the reduction of pressures acting on a structure depends on the value of the internal friction angle, which confirms the earlier research. For a shallow backfill layer however, the reduction is only a local phenomenon and can influence only a part of the structure.

Sign in / Sign up

Export Citation Format

Share Document