scholarly journals Topographical mapping of the mechanical characteristics of the human neurocranium considering the role of individual layers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Johann Zwirner ◽  
Sarah Safavi ◽  
Mario Scholze ◽  
Kai Chun Li ◽  
John Neil Waddell ◽  
...  
Keyword(s):  
Bending Strength ◽  
Layered Composite ◽  
Layered Composites ◽  
Bending Tests ◽  
Three Point Bending ◽  
Failure Loads ◽  
Topographical Mapping ◽  
Positive Correlations ◽  
Age Range

AbstractThe site-dependent load-deformation behavior of the human neurocranium and the load dissipation within the three-layered composite is not well understood. This study mechanically investigated 257 human frontal, temporal, parietal and occipital neurocranial bone samples at an age range of 2 to 94 years, using three-point bending tests. Samples were tested as full-thickness three-layered composites, as well as separated with both diploë attached and removed. Right temporal samples were the thinnest samples of all tested regions (median < 5 mm; p < 0.001) and withstood lowest failure loads (median < 762 N; p < 0.001). Outer tables were thicker and showed higher failure loads (median 2.4 mm; median 264 N) than inner tables (median 1.7 mm, p < 0.001; median 132 N, p = 0.003). The presence of diploë attached to outer and inner tables led to a significant reduction in bending strength (with diploë: median < 60 MPa; without diploë: median > 90 MPa, p < 0.001). Composites (r = 0.243, p = 0.011) and inner tables with attached diploë (r = 0.214, p = 0.032) revealed positive correlations between sample thickness and age. The three-layered composite is four times more load-resistant compared to the outer table and eight times more compared to the inner table.

Bending Strength of Al2O3 Ceramics for Textiles Machinery and Elastic Wave Characteristics by Wavelet Analysis

2007 ◽  
Vol 353-358 ◽  
pp. 345-348
Author(s):  
Ki Woo Nam ◽  
B.G. Ahn ◽  
M.K. Kim ◽  
C.S. Son ◽  
Jin Wook Kim ◽  
...  
Keyword(s):  
Elastic Wave ◽  
Bending Strength ◽  
Test Results ◽  
Composite Ceramics ◽  
Bending Tests ◽  
Three Point Bending ◽  
Wave Signal ◽  
Al2o3 Composite ◽  
Signal Characteristics ◽  
Optimized Conditions

The optimized conditions of pressureless sintering were investigated in order to obtain the bending strength and the elastic wave signal of Al2O3 composite ceramics for textiles machinery. As sintering conditions, a temperature range from 1400°C to 1700°C and time from 30 minutes to 150 minutes were applied. Three-point bending tests were conducted on the sintered materials to obtain the strength property. From the test results, the optimum sintering condition was 1600°C, 100 minutes. Al2O3 composite ceramics showed that the elastic wave signal characteristics had a regular correlativity between the optimum sintering temperature and time as well as the maximum bending strength.

Fabrication of Composite Blocks Containing Alumina Bubble Particles for Porous CBN Abrasive Wheels

2012 ◽  
Vol 499 ◽  
pp. 229-234 ◽  
Author(s):  
Q. Pan ◽  
Wen Feng Ding ◽  
Jiu Hua Xu ◽  
B. Zhang ◽  
H.H. Su ◽  
...  
Keyword(s):  
Fracture Surface ◽  
Dwell Time ◽  
Bending Strength ◽  
Ti Alloy ◽  
Abrasive Wheel ◽  
Bending Tests ◽  
Three Point Bending ◽  
Abrasive Grains ◽  
Alumina Particles ◽  
Vitrified Cbn

Alumina (Al2O3) bubble particles were added into the mixture of CBN abrasive grains, Cu-Sn-Ti alloy and graphite particles to prepare the composite blocks for porous CBN abrasive wheels. The specimens were sintered at the temperature of 920°C for the dwell time of 30 min. The bending strength of the composite blocks was measured by the three-point bending tests. The fracture surface of the blocks was characterized. The results show that, the content of alumina bubble particles does not take significant effect on the mechanical strength of the composite blocks. Even the lowest strength of the composite blocks, 98 MPa, is higher than that of the vitrified CBN abra-sive wheels. Cu-Sn-Ti alloy has bonded firmly alumina particles and CBN grains by means of the chemical reaction and corresponding products. Finally, the chip space was formed through the re-moval of the ceramic wall of the alumina bubble particles within the CBN abrasive wheel during dressing.

scholarly journals Influence of the Infill Orientation on the Properties of Zirconia Parts Produced by Fused Filament Fabrication

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3158 ◽  
Author(s):  
Santiago Cano ◽  
Tanja Lube ◽  
Philipp Huber ◽  
Alberto Gallego ◽  
Juan Alfonso Naranjo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Complex Geometries ◽  
Fused Filament Fabrication ◽  
Moisture Evaporation ◽  
Bending Tests ◽  
Three Point Bending ◽  
Different Types ◽  
Fill Pattern ◽  
The Many

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.

Effect of Moisture Absorption on the Bending Strength of CFRP

2012 ◽  
Vol 450-451 ◽  
pp. 482-485 ◽  
Author(s):  
A Ying Zhang ◽  
Di Hong Li ◽  
Dong Xing Zhang
Keyword(s):  
Moisture Content ◽  
Composite Laminates ◽  
Immersion Time ◽  
Moisture Absorption ◽  
Bending Strength ◽  
Experimental Results ◽  
Bending Tests ◽  
Three Point Bending ◽  
Damage Propagation ◽  
Effect Of Moisture

The effects of moisture content on the bending strength of T300/914 composite laminates that immersed in water for 7 days and 14 days was discussed in this paper. The three-point bending tests were conducted on the composite laminates. Experimental results reveal that the moisture content in the laminates increased with immersion time and that moisture absorption accelerated damage propagation in the composite laminates. The bending strength of the unaged, aged specimens were characterized and analyzed. Compared to the unaged specimens, the bending strength of the composite laminates immersed for 7 and 14 days decreased by 6.62% and 16.98%, respectively. The results revealed that the bending strength of the aged specimens decreased with the increasing immersion time.

Bending Properties and Failure Mechanisms of Tapered 3D Braided Composites

2011 ◽  
Vol 332-334 ◽  
pp. 1468-1471 ◽  
Author(s):  
Can Can Cheng ◽  
Zhao Lin Liu ◽  
Li Fang Liu ◽  
Jian Yong Yu
Keyword(s):  
Failure Modes ◽  
Bending Strength ◽  
Failure Mechanisms ◽  
Reduction Technique ◽  
Braided Composites ◽  
Bending Properties ◽  
Bending Tests ◽  
Three Point Bending ◽  
Bending Modulus ◽  
3D Braided Composites

Tapered 3D braided composites are prepared by column yarn-reduction technique, unit yarn-reduction technique and cutting, respectively. Bending properties in the tapered regions of the composites are obtained by three-point bending tests, and SEM photographs of the fracture surfaces are observed to analyze the failure mechanisms. Results show that bending modulus and bending strength of the yarn-reduction composites are significantly higher than those of the cut composites, and the unit yarn-reduction composites are slightly stronger than the column yarn-reduction composites. The saw-tooth propagation of matrix crackings and interfacial debondings are the primary failure mechanisms of the yarn-reduction composites, while yarn breakages and yarn pulling-outs are the main failure modes of the cut composites.

An investigation on the effect of nanoparticle reinforcement and weld surface shape on bending behavior of rotary friction-welded high-density polyethylene

2021 ◽  
pp. 146442072110441
Author(s):  
Vahid Asghari ◽  
Abdolvahed Kami ◽  
Abbasali Bagheri
Keyword(s):  
High Density Polyethylene ◽  
Joint Strength ◽  
Bending Strength ◽  
Welded Joint ◽  
High Density ◽  
Surface Shape ◽  
Bending Tests ◽  
Three Point Bending ◽  
Rotary Friction Welding ◽  
Bending Behavior

In this research, high-density polyethylene rods were joined together using rotary friction-welding. The effects of nanoparticle reinforcement and weld surface shape on the welded joint strength were investigated. To this aim, high-density polyethylene rods with a length of 50 mm and a diameter of 22 mm were machined, and three weld surface shapes, that is, flat, step, and conic shapes (on male and female counterparts), were created. The high-density polyethylene rods were rotary friction-welded with the addition of ZnO and SiO2 nanoparticles. The bending strength of rotary friction-welded rods was assessed by conduction of three-point bending tests. The results showed that both the weld surface shape and nanoparticles influence the bending strength of the welded joints. It was found that the step sample welds have higher bending strength (average bending depth and force of 6.27 mm and 2027.8 N, respectively). Furthermore, except for the case of flat samples, the addition of the reinforcement nanoparticles resulted in the improvement of the bending strength of the rotary friction-welded rods.

Self-Compassion and Post Traumatic Growth: The Mediating Role of Psychological Flexibility"

2021 ◽  
Author(s):  
Pranati Misurya ◽  
nidhi udgirkar ◽  
Vasundhara Shukla ◽  
Pooja V. Anand
Keyword(s):  
Psychological Flexibility ◽  
Traumatic Experience ◽  
Adaptive Responses ◽  
Mediating Role ◽  
Self Compassion ◽  
Post Traumatic Growth ◽  
Post Traumatic ◽  
Positive Correlations ◽  
Age Range

Self-compassion and post traumatic growth have previously been associated with positive mental health and functioning. They have recently garnered increased research interest in psychotherapeutic milieu as they have also been found to promote adaptive responses to trauma. On the other hand, psychological flexibility represents a variable known to have an impact on many human abilities including the capacity to shift mindsets and behavioral responses and is increasingly being understood as a crucial trait to develop for therapeutic change. The present study sought to examine whether self-compassion would lead to post-traumatic growth as well as the mediating role of psychological flexibility in this relationship. Data was obtained from 208 participants (females=143, males=65), age range=18 to 50 years (M =27 years, S.D = 6.89) who reported being exposed to at least one traumatic experience in the last 5 years. The results found positive correlations between all the three variables used in the study. It was found that self-compassion does lead to post-traumatic growth (c’= 4.9303, CI = 0.4947 to 9.3659, p = 0.0295). Psychological flexibility proved as the mediator between self-compassion and post-traumatic growth, with indirect effect IE = 5.9091 at 95% CI = (3.2340, 8.9695). The findings add to the host of literature on positive functions served by self-compassion, specifically in its contribution towards post traumatic growth. Further, this study explicates the mediating mechanism through which self-compassion exerts its potential effects by pointing out to the role of psychological flexibility.

scholarly journals Bionic Design of the Bumper Beam Inspired by the Bending and Energy Absorption Characteristics of Bamboo

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Meng Zou ◽  
Jiafeng Song ◽  
Shucai Xu ◽  
Shengfu Liu ◽  
Zhiyong Chang
Keyword(s):  
Energy Absorption ◽  
Bending Strength ◽  
Fracture Prevention ◽  
Mass Reduction ◽  
Bamboo Culm ◽  
Bending Tests ◽  
Bumper Beam ◽  
Three Point Bending ◽  
Bending Load ◽  
Better Than

This study conducted quasistatic three-point bending tests to investigate the effect of bamboo node on the energy absorption, bending, and deformation characteristics of bamboo. Results showed that the node had a reinforcing effect on the energy absorption and bending strength of the bamboo culm subjected to bending load. The experimental results demonstrated that nodal samples (NS) significantly outperform internodal samples without node (INS). Under the three-point bending load, the main failure mode of bamboo is the fracture failure. The node also showed split and fracture prevention function obviously. Based on that, a series of bionic bumper beams were designed inspired by the bamboo node. The FEM results indicated that the performance of bionic bumpers was better than that of a normal bumper with regard to bending strength, energy absorption, and being lightweight. In particular, the bionic bumper beam has the best performance with regard to bending, energy absorption, and being lightweight compared with the normal bumper under pole impact. The characteristic of the bionic bumper beam is higher than that of the normal bumper beam by 12.3% for bending strength, 36.9% for EA, and 31.4% for SEA; moreover, there was a mass reduction of 4.9%, which still needs further optimization.

On the “Ceramic Constrained by Metal” Composite Materials

2013 ◽  
Vol 833 ◽  
pp. 266-270
Author(s):  
Chuan Sun ◽  
Yun Kai Li ◽  
Hu Wang ◽  
Ming Ming Wan ◽  
Yun Fei Wang ◽  
...  
Keyword(s):  
Brittle Failure ◽  
Room Temperature ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Metal Composite ◽  
Bending Tests ◽  
Lateral Confinement ◽  
Application Range ◽  
Three Point Bending ◽  
Metal Composite Materials

Ceramics are widely used in every field of contemporary industrial because of its many excellent properties. However, its mechanical property is great brittleness and small toughness for the characteristics of internal chemical bond, which restricts its application range to a large extent. Therefore, how to improve mechanical properties of ceramic materials has been attracted a great attention in the relevant area. For ceramics using at room temperature, a method which can avoid brittle failure by metal confinement outside of ceramics is given. And the feasibility of this method is discussed. Three point bending tests were conduct on ZrO2 ceramics with and without lateral confinement separately. Base on the much of experimental conclusion, the bending strength of ceramic with lateral confinement was improved largely.

scholarly journals CORRELATION BETWEEN HRCT SCORE AND SERUM FERRITIN IN COVID-19 PATIENTS WITH PNEUMONIA IN TERTIARY CARE HOSPITAL, MGM HOSPITAL AURANGABA

2021 ◽  
pp. 52-54
Author(s):  
Saurabh Govind Pad ◽  
Devidas Dahiph ◽  
Saurabh Kakani ◽  
Vimal Dugad
Keyword(s):  
Serum Ferritin ◽  
Pearson Correlation ◽  
Tertiary Care ◽  
P Value ◽  
Care Hospital ◽  
The Social ◽  
Severe Group ◽  
Positive Correlations ◽  
Age Range

This study was aimed to correlate the HRCT score and serum ferritin in diagnosed cases of COVID19 patients with pneumonia.During the pandemic of COVID-19,there was sudden surge in the numbers of HRCT chest scans and along with this amongst the various laboratory investigations serum ferritin was done to observe the role of cytokines which helps in disease progression.The main purpose of this study was to correlate the severity of disease on HRCT chest scan with serum ferritin levels. Aim:To correlate the HRCT score and serum ferritin in diagnosed cases of COVID19 patients with pneumonia. Materials and methods: We included 59 patients (38 men, 21 women age range 18-78years) with documented COVID19 were reviewed. All patients underwent RTPCR tests and had a noncontrast HRCT scan done at presentation. Estimation of serum ferritin was analyzed by using chemiluminescence method.The subjects were divided into three groups:mild,moderate and severe on the basis of HRCT score. Each group's HRCT score correlated with serum ferritin. The details were recorded on a prestructured proforma. The Pearson correlation coefficient test was used for correlations, and p value less than 0.05 was defined as statistically significant.The data was analyzed using Statistical Package for the Social Sciences (SPSS). Results: Out of 59 patients,21 patients were included in the mild group,31 were included in the moderate group and 7 were included in the severe group.CT severity score was found to be positively correlated with ferritin levels (p < 0.001). Strong positive correlations were found between CT scores and serum ferritin in mild (r = 0.84),Moderate (r = 0.92) and severe group (r = 0.082)

Sign in / Sign up

Export Citation Format

Share Document