scholarly journals The impact performance of bamboo oriented strand board and computed tomography technique for detecting internal damage

BioResources ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. 6707-6721
Author(s):  
Yuhui Sun ◽  
Zehui Jiang ◽  
Xiubiao Zhang ◽  
Zhengjun Sun ◽  
Xiaomeng Yang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Oriented Strand Board ◽  
Energy Levels ◽  
Time History ◽  
Ct Scanning ◽  
Projectile Energy ◽  
Impact Properties ◽  
Impact Performance ◽  
Strand Orientation ◽  
The Impact

The objective of this study was to investigate the impact performance of bamboo oriented strand board under different impact energy. Bamboo oriented strand board with two types of strand orientation distribution, both with mainly parallel aligned strand orientation (LVSL) and three-layer assembly with orthogonally oriented strands (BOSB), were prepared. The impact properties of the boards, both untreated and treated with submersion, were investigated at seven energy levels. Additionally, the damage morphology was characterized using an X-ray computed tomography (CT) scanner. The results indicated that BOSB provided a larger maximum load carrying capacity, and represented superior impact properties compared to LVSL. The shapes of force/energy–time history of BOSB and LVSL were different from projectile energy levels, and they were related to the specimen destruction forms via CT scanning. Moreover, CT scanning revealed that LVSL and BOSB exhibited similar damage behaviors, which mainly included delamination and fibers breakage. The dent depth of BOSB on the impact site was less than LVSL’s for touch types, and there was more internal fracture inside the layers of LVSL at relatively higher energy levels of 300 J and 450 J. Furthermore, BOSB still exhibited better impact performance than LVSL under the condition of submersion.

scholarly journals Dual-Energy Computed Tomography of the Liver: Uses in Clinical Practices and Applications

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 161
Author(s):  
Masakatsu Tsurusaki ◽  
Keitaro Sofue ◽  
Masatoshi Hori ◽  
Kosuke Sasaki ◽  
Kazunari Ishii ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Liver Tumors ◽  
Energy Levels ◽  
Ct Scanning ◽  
Dual Energy ◽  
Liver Imaging ◽  
X Rays ◽  
Clinical Practices ◽  
Dual Energy Computed Tomography ◽  
Noise Ratio

Dual-energy computed tomography (DECT) is an imaging technique based on data acquisition at two different energy settings. Recent advances in CT have allowed data acquisitions and simultaneous analyses of X-rays at two energy levels, and have resulted in novel developments in the field of abdominal imaging. The use of low and high X-ray tube voltages in DECT provide fused images that improve the detection of liver tumors owing to the higher contrast-to-noise ratio (CNR) of the tumor compared with the liver. The use of contrast agents in CT scanning improves image quality by enhancing the CNR and signal-to-noise ratio while reducing beam-hardening artifacts. DECT can improve detection and characterization of hepatic abnormalities, including mass lesions. The technique can also be used for the diagnosis of steatosis and iron overload. This article reviews and illustrates the different applications of DECT in liver imaging.

scholarly journals Effect of a New Grain Refiner (Al–Ti–Mg–Ce) on Hardness, Tensile, and Impact Properties of Al–7Si Alloy

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 228 ◽  
Author(s):  
Jitao Zhao ◽  
Mingfang Shi ◽  
Zhenqing Wang ◽  
Lidan Xu
Keyword(s):  
Impact Toughness ◽  
Strain Rate ◽  
Tensile Properties ◽  
Rate Sensitivity ◽  
Mechanical Tests ◽  
Hopkinson Pressure Bar ◽  
Grain Refiner ◽  
Impact Properties ◽  
Impact Performance ◽  
The Impact

Through studying the effects of the Al–5Ti-x(Mg–30%Ce) refiner on the microstructure of the Al–7Si alloy, we investigated the hardness, tensile, and impact properties of the Al–Si alloy before and after refinement. The refinement results show that Mg–30%Ce can improve the refinement effect of Al–5Ti on Al–7Si, and also refine α-Al and eutectic Si in Al–7Si. When 2%Mg–30%Ce is added, the refining effect of the aluminum–silicon alloy is most obvious. After refinement, the hardness and tensile properties of the Al–7Si alloy improve. When 2%Mg–30%Ce is added to the refiner, the tensile properties of the Al–Si alloy are the best. Dynamic mechanical tests were conducted on refined Al–7Si alloy. The impact toughness of Al–7Si–(Al–5Ti-2(Mg–30%Ce) improved and the impact toughness reached 34.91 J/cm2, which is 78.7% higher than that of Al–7Si–(Al–5Ti) specimens. The separate Hopkinson pressure bar test results show that, under a high strain rate, the strain rate sensitivity of the prepared Al–Si alloy is significant. The specimens of Al–7Si–(Al–5Ti-2(Mg–30%Ce) demonstrated the best anti-impact performance at the same velocity.

scholarly journals The Low Velocity Impact Properties of Pandanus Fiber Composites

2017 ◽  
Vol 895 ◽  
pp. 56-60 ◽  
Author(s):  
Hoo Tien Nicholas Kuan ◽  
Meng Chuen Lee ◽  
Amir Azam Khan ◽  
Marini Sawawi
Keyword(s):  
Impact Loading ◽  
Volume Fraction ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Impact Properties ◽  
Velocity Impact ◽  
Impact Performance ◽  
Biodegradable Composites ◽  
Penetration Tests ◽  
The Impact

The impact properties of biodegradable Pandanus atrocarpus composite laminate is studied. Laminate samples were fabricated using a hot compression molding technique with high-density polyethylene and extracted Pandanus fiber. Pandanus composites were tested under impact loading in order to study their relative impact performance. Under low velocity impact loading, Pandanus fiber laminates offered an excellent resistance to impact penetration. Tests have shown that increasing the volume fraction of Pandanus fiber can enhance the toughness of the composite. The biodegradable composites imply attractive properties that may be accessible for use in engineering sectors.

A Method for Assessing the Overall Impact Performance of Riot Helmets

2003 ◽  
Vol 19 (3) ◽  
pp. 246-254 ◽  
Author(s):  
Jean-Philippe Dionne ◽  
Ismail El Maach ◽  
Ahmed Shalabi ◽  
Aris Makris
Keyword(s):  
Comparative Study ◽  
Impact Energy ◽  
Energy Levels ◽  
Performance Impact ◽  
Impact Performance ◽  
Frontal Impacts ◽  
National Institute Of Justice ◽  
Crowd Control ◽  
The Face ◽  
The Impact

The objective of the present paper is to investigate the overall impact performance of various riot helmets in a comparative study. The National Institute of Justice (NIJ-0104.02) and the Canadian Standards Association (CSA-Z611-02) standards regulate the use of riot helmets in North America. Both sets of standards have a number of requirements for impact performance. Impact tests carried out with the use of a drop tower apparatus compliant with NIJ test protocols demonstrated large differences in impact attenuation level among the helmets from six manufacturers in terms of frontal and lateral impacts to the shell, and face-shield deflection. For instance, the impact energy yielding a head form acceleration of 300 g’s was measured for each helmet for frontal impacts on the helmet shell. Values ranging from 69 J up to 171 J were obtained. The energy levels of typical crowd-control threats, e.g., baton blows and projectiles, were quantified and compared with the impact energy values used in the standards. It is observed that the NIJ face-shield deflection requirement is low as compared to actual riot threats, whereas the CSA requirements are more in line with these threats. A novel method was devised to objectively assign a global impact performance score to each helmet. This method takes into account the frontal and lateral impacts to the shell as well as the face-shield deflection tests. It is based on the directional origin of the threat and the geometry of the helmets (frontal percentage area of the visor). From these global performance scores, it is possible to obtain a ranking of the various riot helmets used in the present comparative study. Based on the analysis of the global scores, it was found that appropriate protection of the face (through an impact resistant visor) is the key feature for a helmet that will be used in riot environments.

Research on the Dynamic Characteristics of a Sphere Material

2012 ◽  
Vol 246-247 ◽  
pp. 482-486
Author(s):  
Yong Cheng Wang
Keyword(s):  
Dynamic Characteristics ◽  
Split Hopkinson Pressure Bar ◽  
Polymer Materials ◽  
Butadiene Rubber ◽  
Hopkinson Pressure Bar ◽  
Impact Properties ◽  
Impact Performance ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact

In this paper, we make a research on the dynamic characteristics of a sphere material, mainly using golf as an example. Golf is composed of such as poly butadiene rubber or other synthetic rubber, ion resin, etc. and different viscoelastic materials. The viscoelastic characteristics of this material are selected as spectrometer for evaluation. However, the impact performance of the golf course materials cannot pass such a test to assess, because golf have great impact on the deformation and high strain rate viscoelastic spectrometer. On the other hand, the impact properties of the metal can be used to assess the split Hopkinson pressure bar. However, the rod is not suitable to be used to evaluate the strain wave interference and noise propagation in the impact properties of the polymer materials. Therefore, the split Hopkinson pressure bar has been modified to make it more applicable to the valuation of the polymer materials. The article is based on the concept of modified split Hopkinson pressure bar to make the golf impact evaluation of the performance materials.

Analysis of Laminate Configuration on Impact Properties of Glass Fibre Epoxy Nanocomposites

2012 ◽  
Vol 488-489 ◽  
pp. 686-690
Author(s):  
A. Thiagarajan ◽  
K. Palaniradja ◽  
N. Rajesh Mathivanan ◽  
M. Naresh
Keyword(s):  
Energy Absorption ◽  
Glass Fibre ◽  
Energy Levels ◽  
Testing Machine ◽  
Maximum Load ◽  
Epoxy Nanocomposites ◽  
Impact Properties ◽  
Glass Fibre Reinforced ◽  
Falling Weight ◽  
The Impact

The impact behaviors of glass fibre reinforced/epoxy nanocomposites were studied by experimental using instrumental falling weight testing machine at three different energy levels. Two types of laminates were prepared by hand lay-up method with varying nanoclay into the epoxy in a 1%, 3% and 5%, respectively. The structures of nanocomposites were studied using X-ray diffraction (XRD). It was found that the nanoclay was orderly exfoliated in the epoxy resin. The impact properties of maximum load and energy absorption were determined. It was observed that addition of 3% nanoclay into the epoxy, the maximum load was enhanced by 32% and energy absorption by 24% at the energy level of 24.89J. The impact fractured surface morphology of the glass fibre/epoxy nanocomposites was analyzed using scanning electron microscopy (SEM).

Effects of Straining, Aging, and Stress-Relieving on Mechanical Properties of Steels for Arctic Service

1975 ◽  
Vol 97 (2) ◽  
pp. 408-416 ◽  
Author(s):  
R. J. Jesseman ◽  
R. C. Smith
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Carbon Content ◽  
Shape Control ◽  
Energy Levels ◽  
Aged Condition ◽  
Impact Properties ◽  
Stress Relieving ◽  
The Impact

The effects of straining, straining + aging, and straining + aging + stress-relieving on tensile and Charpy V-notch impact properties were determined for several candidate arctic pipe and fitting steels. Possible compositional and processing means to maintain high as-rolled energy levels in strained + aged pipe are discussed. Heat treatment of 787 and Mn-Mo-Cb, as would be necessary in fittings, increased toughness to the level that degradation due to straining + aging was readily accommodated even at −80°F (−62°C) test temperatures. For fittings designed to −20°F (−29°C) or higher service temperatures, Armco VNT-QT with restricted carbon content and sulfide shape control provided adequate toughness in the strained + aged condition. After stress-relieving, the impact properties improved enough to allow use of this grade at −80°F (−62°C).

Influence of microstructural voids on the mechanical and impact properties in commingled E-glass/polypropylene thermoplastic composites

2002 ◽  
Vol 216 (2) ◽  
pp. 85-100 ◽  
Author(s):  
C Santulli ◽  
R Brooks ◽  
C D Rudd ◽  
A C Long
Keyword(s):  
Shear Strength ◽  
Composite Structures ◽  
Three Dimensional ◽  
Interlaminar Shear Strength ◽  
Void Content ◽  
Impact Properties ◽  
Impact Performance ◽  
Impact Tests ◽  
Interlaminar Shear ◽  
The Impact

In recent years, the compression moulding of E-glass/polypropylene commingled composites has been thoroughly investigated. In particular, in the University of Nottingham, a number of studies have been carried out, trying to correlate moulding parameters with mechanical properties and microstructural void content. However, some aspects of commingled composites have received less coverage so far and are therefore dealt with in this paper. These concern the effect of the processing conditions of these materials on interlaminar shear strength and impact properties and the influence of the synergy between processing, microstructure and properties on the impact performance of commingled composite structures. With this aim, flat plaques of E-glass/polypropylene commingled composites with a different fibre architecture (two-and three-dimensional) were non-isothermally compression moulded under various moulding conditions and then tested. The test programme included falling weight impact tests with a staircase procedure, Charpy impact tests and interlaminar shear strength (ILSS) tests. To evaluate the consolidation of the laminates, void content measurement using optical microscopy was related to ILSS and impact test results. In particular, the specific issues arising in moulding laminates with added three-dimensional fibres were studied. These include correct placement of the tow, sufficient preheating of thick laminates and nesting of the layers during moulding. The results of these tests are discussed in the light of the moulding conditions and quality, and conclusions are drawn regarding optimum moulding conditions for impact performance. Finally, indications on the reliability and possible improvement of the moulding procedure to yield a sufficient moulding quality, even with large thickness, are also provided. The knowledge acquired on material consolidation properties is applied in the manufacture of an automotive side intrusion beam: problems due to the scale effect are also discussed.

Morphology and Affinities of Ampelocissites Seeds (Vitaceae: Ampelopsis clade) from the Paleogene of Texas, USA

2020 ◽  
Vol 45 (3) ◽  
pp. 478-482
Author(s):  
Steven R. Manchester
Keyword(s):  
Computed Tomography ◽  
Cross Sections ◽  
Seed Coat ◽  
Ct Scanning ◽  
Seed Morphology ◽  
Early Eocene ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Fossil Seeds ◽  
Fossil Genus

Abstract—The type material on which the fossil genus name Ampelocissites was established in 1929 has been reexamined with the aid of X-ray micro-computed tomography (μ-CT) scanning and compared with seeds of extant taxa to assess the relationships of these fossils within the grape family, Vitaceae. The specimens were collected from a sandstone of late Paleocene or early Eocene age. Although originally inferred by Berry to be intermediate in morphology between Ampelocissus and Vitis, the newly revealed details of seed morphology indicate that these seeds represent instead the Ampelopsis clade. Digital cross sections show that the seed coat maintains its thickness over the external surfaces, but diminishes quickly in the ventral infolds. This feature, along with the elliptical chalaza and lack of an apical groove, indicate that Ampelocissites lytlensis Berry probably represents Ampelopsis or Nekemias (rather than Ampelocissus or Vitis) and that the generic name Ampelocissites may be useful for fossil seeds with morphology consistent with the Ampelopsis clade that lack sufficient characters to specify placement within one of these extant genera.

scholarly journals Simultaneous Casualty Admissions—Do they Affect Treatment in the Receiving Trauma Center?

2021 ◽  
Author(s):  
Michel Paul Johan Teuben ◽  
Carsten Mand ◽  
Laura Moosdorf ◽  
Kai Sprengel ◽  
Alba Shehu ◽  
...  
Keyword(s):  
Injury Severity ◽  
Damage Control ◽  
Ct Scanning ◽  
Mortality Rates ◽  
Trauma Centers ◽  
Simultaneous Treatment ◽  
Diagnostic Pathway ◽  
Injured Patients ◽  
The Impact ◽  
Mean Time

Abstract Background Simultaneous trauma admissions expose medical professionals to increased workload. The impact of simultaneous trauma admissions on hospital allocation, therapy, and outcome is currently unclear. We hypothesized that multiple admission-scenarios impact the diagnostic pathway and outcome. Methods The TraumaRegister DGU® was utilized. Patients admitted between 2002–2015 with an ISS ≥ 9, treated with ATLS®- algorithms were included. Group ´IND´ included individual admissions, two individuals that were admitted within 60 min of each other were selected for group ´MULT´. Patients admitted within 10 min were considered as simultaneous (´SIM´) admissions. We compared patient and trauma characteristics, treatment, and outcomes between both groups. Results 132,382 admissions were included, and 4,462/3.4% MULTiple admissions were found. The SIM-group contained 1,686/1.3% patients. The overall median injury severity score was 17 and a mean age of 48 years was found. MULT patients were more frequently admitted to level-one trauma centers (68%) than individual trauma admissions were (58%, p < 0.001). Mean time to CT-scanning (24 vs. 26/28 min) was longer in MULT / SIM patients compared to individual admissions. No differences in utilization of damage control principles were seen. Moreover, mortality rates did not differ between the groups (13.1% in regular admissions and 11.4%/10,6% in MULT/SIM patients). Conclusion This study demonstrates that simultaneous treatment of injured patients is rare. Individuals treated in parallel with other patients were more often admitted to level-one trauma centers compared with individual patients. Although diagnostics take longer, treatment principles and mortality are equal in individual admissions and simultaneously admitted patients. More studies are required to optimize health care under these conditions.

Sign in / Sign up

Export Citation Format

Share Document