scholarly journals Ударное разрушение кристаллического, аморфизованного имплантацией Ar-=SUP=-+-=/SUP=- и аморфного диоксида кремния

2022 ◽  
Vol 92 (2) ◽  
pp. 279
Author(s):  
И.П. Щербаков ◽  
А.Е. Чмель
Keyword(s):  
Comparative Analysis ◽  
Ion Implantation ◽  
Silicon Dioxide ◽  
Impact Loading ◽  
Impact Damage ◽  
Energy Distributions ◽  
Mechanical Fracture ◽  
Before And After ◽  
Oxygen Groups ◽  
The Impact

The mechanical fracture of silicon dioxide initiates the mechanoluminescence (ML) lighting due to multiple breakage of interatomic bonds with producing non-bridged oxygen groups of [Si–O–]. The detected ML signals consisted of series of pulses, the energy of which is proportional to the number of photons irradiated from the broken bonds. The comparative analysis of the energy distributions in ML series induced by the impact damage of the surface of crystalline and vitreous SiO2 before and after the Ar+-ion implantation was conducted. The interplay between random and correlated accumulation of broken bonds under the impact loading was found and discussed.

scholarly journals Impact Loading During Distracted Running Before and After Auditory Gait Retraining

2018 ◽  
Vol 39 (14) ◽  
pp. 1075-1080 ◽  
Author(s):  
Eric Ching ◽  
Winko An ◽  
Ivan Au ◽  
Janet Zhang ◽  
Zoe Chan ◽  
...  
Keyword(s):  
Visual Feedback ◽  
Impact Loading ◽  
Auditory Feedback ◽  
Loading Rate ◽  
Real Life ◽  
Gait Retraining ◽  
Positive Acceleration ◽  
Before And After ◽  
The Impact ◽  
High Sound

AbstractVisual feedback gait retraining has been reported to successfully reduce impact loading in runners, even when the runners were distracted. However, auditory feedback is more feasible in real life application. Hence, this study compared the peak positive acceleration (PPA), vertical average (VALR) and instantaneous (VILR) loading rate during distracted running before and after a course of auditory feedback gait retraining in 16 runners. The runners were asked to land with softer footfalls with and without auditory feedback. Low or high sound pitch was generated according to the impact of particular footfall, when compared with the preset target. Runners then received a course of auditory gait retraining, and after the gait retraining, runners completed a reassessment. Runners before gait retraining exhibited lower PPA, VALR and VILR with augmented auditory feedback (p<0.049). We found a reduction in PPA, VALR and VILR after gait retraining, regardless of the presence of feedback (p<0.018). However, runners after gait retraining did not demonstrate further reduction in PPA and VALR with auditory feedback (p>0.104). A small effect of auditory feedback on VILR in runners after gait retraining was observed (p=0.032). Real time auditory feedback gait retraining is effective in impact loading reduction, even when the runners were distracted.

Low Velocity Impact on Fiber Reinforced Geocomposites

2016 ◽  
Vol 827 ◽  
pp. 145-148 ◽  
Author(s):  
Sneha Samal ◽  
David Reichmann ◽  
Iva Petrikova ◽  
Bohdana Marvalova
Keyword(s):  
Impact Damage ◽  
Acoustic Vibration ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Behaviour ◽  
Reinforced Composite ◽  
Before And After ◽  
Two Parameters ◽  
The Impact

Low velocity impact strength of the fabric reinforced geocomposite has investigated in this article. Various fabrics such as carbon and E-glass were considered for reinforcement in geopolymer matrix. The primary two parameters such as low velocity, impact damage modes are explained on the E-glass and carbon based fabric geocomposite. The onset mode of damage to failure mode is examined through C-scan analysis. The quality of the composite is observed using c-scan with acoustic vibration mode of sensor before and after impact test. Then the effect of fabric and matrix on the impact behaviour is discussed. Residual strength of the composite is measured to determine post impact behaviour. It has been observed that resistance properties of E-glass reinforced composite is better than carbon fabric reinforced composite.

scholarly journals Commuting for work and neighbourhood energy consumption

2021 ◽  
Author(s):  
Dil Rowshan
Keyword(s):  
Energy Consumption ◽  
Comparative Analysis ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Travel Behavior ◽  
Active Transportation ◽  
Before And After ◽  
Motorized Vehicles ◽  
The Impact ◽  
Growth Centres

This study aimed to explore the impact of the Places to Grow Plan 2006 on travel behavior of the work commuters living in GTHA. A comparative analysis was done between the year 2001 and 2011 which represent the situations five year before and after the implementation of the Plan. Data were collected from Transportation Tomorrow Survey. The study revealed that in 2011, energy consumption by motorized vehicles increased in the Traffic Assessment Zones of GTHA around the Growth Centres designated by the Places to Grow Plan. Active transportation increased mainly in Toronto in 2011. It is apprehended that the intensification strategy of the Places to Grow Plan contributed in increasing the energy consumption of work commuters either by increasing the number of trips or length of trips made by motorized vehicles (including cars and different forms of transit) which also affect the Greenhouse Gas emissions in the atmosphere.

scholarly journals Crushing Susceptibility of Vetch Seeds Under Impact Loading

2017 ◽  
Vol 50 (4) ◽  
pp. 5-16
Author(s):  
F. Shahbazi
Keyword(s):  
Moisture Content ◽  
Impact Energy ◽  
Impact Loading ◽  
Impact Damage ◽  
Mechanical Damage ◽  
Seed Moisture Content ◽  
Mean Values ◽  
Seed Moisture ◽  
Mathematical Relationships ◽  
The Impact

AbstractMechanical damage of seeds due to harvest, handling and other process is an important factor that affects the quality and quaintly of seeds. The objective of this research was to determine the effects of moisture content and the impact energy on the breakage susceptibility of vetch seeds. The experiments were conducted at moisture contents of 7.57 to 25% (wet basis) and at the impact energies of 0.1, 0.2 and 0.3 J, using an impact damage assessment device. The results showed that impact energy, moisture content, and the interaction effects of these two variables significantly influenced the percentage breakage in vetch seeds (p<0.01). Increasing the impact energy from 0.1 to 0.3 J caused a significant increase in the mean values of seeds breakage from 41.69 to 78.67%. It was found that the relation between vetch seeds moisture content and seeds breakage was non-linear, and the extent of damaged seeds decreased significantlyas a polynomial (from 92.47 to 33.56%) with increasing moisture (from 7.57 to 17.5%) and reached a minimum at moisture level of about 17.5%. Further increase in seed moisture, however, caused an increase in the amount of seeds breakage. Mathematical relationships composed of seed moisture content and impact energy, were developed for accurately description the percentage breakage of vetch seeds under impact loading. It was found that the models have provided satisfactory results over the whole set of values for the dependent variable.

Experimental and simulation investigation on BVID and CAI behaviors of CFRP laminates manufactured by RTM technology

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fang Chen ◽  
Weixing Yao ◽  
Wen Jiang
Keyword(s):  
Compressive Strength ◽  
Impact Damage ◽  
Projection Area ◽  
Element Analysis ◽  
Mechanical Fracture ◽  
Content Type ◽  
Explicit Finite Element ◽  
Compression Load ◽  
Cfrp Laminates ◽  
The Impact

Purpose The purpose of this paper is to synthetically investigate the impact damage responses of carbon fiber reinforced polymer (CFRP) and its influence on the compression mechanical responses of CFRP laminates, including damage distribution, residual compressive strength and fracture morphology. Design/methodology/approach A progressive damage simulation model is developed to analyze the complicated damage responses of CFRP laminates that are manufactured by resin transfer method (RTM) technology. Based on the ABAQUS/explicit finite element analysis solver, a VUMAT code is proposed to descript the composite materials’ damage behaviors under both impact and compression load. Adopting this proposed model, the primary mechanical indicators of four groups’ 5284RTM/U3160 CFRP laminates with different stacking sequences are predicted. Moreover, impact and compression after impact tests are conducted to verify the accuracy of simulation results. Findings Both simulation and experimental results show that the impact damage with low visible detectability can significantly reduce composites’ compressive strength. For all four groups’ composite laminates, the residual strength ratio is around 35% or even lower. The kernel impact damage near the plates’ geometric center promotes the degradation process of local materials and finally leads to the early occurrence of mechanical fracture. In addition, the impact damage projection area is not sensitive to the parameters of stacking sequences, while the residual compression strength is proportional to the number of 0-degree layers within whole laminates. Originality/value This study helps to understand the effect of an impact event on CFRP laminates’ compressive bearing capacity and provides a numerical method in simulating the damage responses under both impact and compression load.

A Study on Low Velocity Impact of Woven Glass/Phenolic Composite Laminates Considering Environmental Effects

2005 ◽  
Vol 297-300 ◽  
pp. 1303-1308 ◽  
Author(s):  
Jae Hoon Kim ◽  
Duck Hoi Kim ◽  
Hu Shik Kim ◽  
Byoung Jun Park
Keyword(s):  
Compressive Strength ◽  
Environmental Effects ◽  
Impact Loading ◽  
Composite Laminates ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Internal Damage ◽  
The Impact ◽  
Phenolic Composite

The objectives of this study are to evaluate the internal damage and compressive residual strength of composite laminate by impact loading. To investigate the environmental effects, as-received and accelerated-aged glass/phenolic laminates are used. UT C-Scan is used to determine the impact damage characteristics and CAI tests are carried out to evaluate quantitatively the reduction of compressive strength by impact loading. The damage modes of the woven glass/phenolic laminates are evaluated. In the case of the accelerated-aged laminates, as aging time increases, initial failure energy and residual compressive strength decrease.

scholarly journals Commuting for work and neighbourhood energy consumption

2021 ◽  
Author(s):  
Dil Rowshan
Keyword(s):  
Energy Consumption ◽  
Comparative Analysis ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Travel Behavior ◽  
Active Transportation ◽  
Before And After ◽  
Motorized Vehicles ◽  
The Impact ◽  
Growth Centres

This study aimed to explore the impact of the Places to Grow Plan 2006 on travel behavior of the work commuters living in GTHA. A comparative analysis was done between the year 2001 and 2011 which represent the situations five year before and after the implementation of the Plan. Data were collected from Transportation Tomorrow Survey. The study revealed that in 2011, energy consumption by motorized vehicles increased in the Traffic Assessment Zones of GTHA around the Growth Centres designated by the Places to Grow Plan. Active transportation increased mainly in Toronto in 2011. It is apprehended that the intensification strategy of the Places to Grow Plan contributed in increasing the energy consumption of work commuters either by increasing the number of trips or length of trips made by motorized vehicles (including cars and different forms of transit) which also affect the Greenhouse Gas emissions in the atmosphere.

scholarly journals Rehabilitation of a Vehicle Impact Damaged Concrete Bridge Girder with GFRP Rebars

2018 ◽  
Vol 199 ◽  
pp. 09007
Author(s):  
Nur Yazdani ◽  
Maria Montero
Keyword(s):  
Impact Damage ◽  
Repair Process ◽  
Load Testing ◽  
Mortar Strength ◽  
Repair Mortar ◽  
Gravity Load ◽  
Before And After ◽  
Final Design ◽  
The Impact ◽  
Gfrp Rebars

Overpass bridge girders are susceptible to impact damage of over-height vehicles, creating a traffic hazard and structural deficiency. The repair for a damaged girder has to meet adequate criteria for the safety, repair time and economy. This paper presents a case study for the repair of such an impact damaged concrete girder on the Lyndon B. Johnson Express construction project, located on I-635 and I-35 freeways in Dallas, Texas. The impact caused concrete loss and exposed several restressing strands on the exterior girder. The overpass had been completed while the old route was open below, causing a temporary vertical lower clearance than the final design, leading to the impact. The novel and innovative repair process involved fiber glass (GFRP) rebars, bonding epoxy and repair mortar. These rebars enhanced the flexural capacity of the repaired section and supplemented the mortar strength. Onsite load testing was employed to verify the performance of the repaired structure. Theoretical model of the composite girder before and after repair was employed. The strain data from the model compared well with the load testing data. The repair scheme drastically increased the stiffness of the damaged girder, resulting in about 50% reduction in the bottom strains. The beneficial effect of the repair resulted in large increases in the net compressive stresses (200–300%) at the girder bottom through the increase of the section stiffness and reduction of the gravity load stresses. Stresses remained well below the elastic range for concrete and the GFRP rebars.

Comparative analysis of the impact of blood collection systems on the results of the study of indicators hemostasis system

2020 ◽  
Vol 65 (10) ◽  
pp. 607-610
Author(s):  
O. V. Petrova ◽  
O. V. Dymova ◽  
D. K. Tverdokhlebova ◽  
E. V. Smeltsova ◽  
E. V. Panova ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Visual Assessment ◽  
Blood Collection ◽  
Exclusion Criteria ◽  
Coagulation Tests ◽  
Before And After ◽  
Parametric Statistics ◽  
Inflammatory Drugs ◽  
The Impact ◽  
Routine Coagulation

Comparative analysis of the impact of blood collection systems on the results of routine coagulation tests. The aim of this study was to conduct comparative analysis of the effects of blood collection systems on the results of routine coagulation tests. The study involved practically healthy women over 18 years of age female (n=30). Inclusion criteria: practically healthy individuals. Exclusion criteria: taking non-steroidal anti-inflammatory drugs, or oral contraceptives. Blood collection was carried out in the following systems: 1 system-Vacuette Premium,2 system- Improvacuter, 3 system- BD Vacutainer® Plus. Before and after centrifugation, visual assessment of tubes was performed.No signs for the presence of clots, hemolysis, or insufficient filling was observed. In each sample we measured prothrombin time (PV, sec), activated partial thromboplastin time (APTT, sec), and fibrinogen (F, g/l) by clotting method on the automatic coagulometer «Sta Compact» («Diagnostica Stago», France). The results of laboratory analyses were processed using parametric and non - parametric statistics using The Statistica 12.0 software. At the preanalytical laboratory stage, there were no differences when using systems for blood sampling: the clots and hemolysis were not detected in the samples, the level of filling of the sistems was sufficient. Comparative analysis revealed small, though statistically significant, differences for: PT when comparing Improvacuter wiht Vacuette Premium or BD Vacutainer®; APPT when comparing Improvacuter wiht Vacuette Premium. No differences were observed for Fg levels. Our results support the data available in the literature on the effects of blood-taking systems on hemostasis , which should be taken into account when purchasing blood collection systems.

scholarly journals RESEARCHES OF THE POSSIBILITY OF ASSESSING DAMAGE TO THREE-LAYER STRUCTURES BY IMPACT DAMAGE BY METHOD OF COMPUTED X-RAY TOMOGRAPHY

2020 ◽  
pp. 20-28
Author(s):  
A. A. Larin ◽  
M. Yu. Fedotov ◽  
O. N. Budadin ◽  
S. O. Kozel’skaya ◽  
V. I. Reznichenko
Keyword(s):  
Impact Damage ◽  
Carbon Composite ◽  
General Description ◽  
Destructive Testing ◽  
X Ray ◽  
Composite Plating ◽  
Layer Structures ◽  
Before And After ◽  
Aluminum Honeycomb ◽  
The Impact

This article describes the results of researches on the assessment of the applicability of the method of computer X-ray tomography for monitoring the internal structure of three-layer structures with carbon composite cladding and aluminum honeycomb, a general description of the method is given. It has been experimentally shown that the method of computed X-ray tomography allows one to evaluate the porosity of carbon composite plating, to identify stratifications resulting from impact. Comparative results of the non-destructive testing of a three-layer carbon composite sample made by autoclave molding from a unidirectional carbon tape and an adhesive epoxy matrix and aluminum honeycomb before and after impact are presented. It was revealed that for the upper lining of a carbon composite, the maximum number of macrodefects of the type stratification occurs directly in the impact zone and adjacent local areas, and leads to a change in the geometry of the skin and honeycomb aggregate, as well as a multiple increase in porosity in comparison with the results of the preimpact test. It should be noted that in the lower skin the porosity due to impact increases slightly, evenly distributed over the volume of the skin, which indicates the occurrence of cracking in the polymer matrix of the carbon composite.Thus, the method of computer x-ray tomography is an effective tool for controlling the damage of three-layer structures by impact.

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