scholarly journals Characteristics of Progressive Damage of ZnO Nanowires during Contact Sliding under Relatively Low Loads

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Kyeong Hee Kang ◽  
Hae Jin Kim ◽  
Dae-Eun Kim

ZnO nanowires have received much interest owing to their particular structural and piezoelectric properties. For widespread application of ZnO nanowires in various nanotechnologies, the mechanical reliability of the nanowires should be assessed. In this paper, the damage characteristics of vertically grown ZnO nanowires due to contact sliding against a 2 mm diameter steel ball under relatively low loads were investigated. Frictional behavior and wear characteristics of the specimens were assessed. Furthermore, contact sliding tests were performed inside an SEM to monitor the progression of damage of the nanowires. It was found that the friction coefficient was about 0.35 under all loads while the damage characteristics of the nanowires were quite different for each load. The large diameter nanowires tended to fracture earlier than the small diameter nanowires. Wear tests performed inside the SEM confirmed the surface damage characteristics observed during the friction tests.

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.


2021 ◽  
pp. 002199832098559
Author(s):  
Yun-Tao Zhu ◽  
Jun-Jiang Xiong ◽  
Chu-Yang Luo ◽  
Yi-Sen Du

This paper outlines progressive damage characteristics of screwed single-lap CFRPI-metal joints subjected to tensile loading at RT (room temperature) and 350°C. Quasi-static tensile tests were performed on screwed single-lap CCF300/AC721-30CrMnSiA joint at RT and 350°C, and the load versus displacement curve, strength and stiffness of joint were gauged and discussed. With due consideration of thermal-mechanical interaction and complex failure mechanism, a modified progressive damage model (PDM) based on the mixed failure criterion was devised to simulate progressive damage characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint, and simulations correlate well with experiments. By using the PDM, the effects of geometry dimensions on mechanical characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint were analyzed and discussed.


Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.


2013 ◽  
Vol 353-356 ◽  
pp. 459-462
Author(s):  
Ying Jie Zheng ◽  
Bin Fang ◽  
Lian Xiang Li

Pile tip absolute settlement curves and relative settlement curves of several working cases were analyzed. It is found that load-settlement curve characteristic related to the selection standard. The tip resistance initial stiffness of each case was analyzed. Results show that the small diameter pile has higher initial stiffness than large diameter pile, embedded depth has little influence on initial stiffness ratio, but increment of initial stiffness is linear with embedded depth growth.


Author(s):  
E. Rehleckaya ◽  
A. Dymkov ◽  
L. Lazarets ◽  
A. Maltsev

Purpose: Install the influence of the «small diameter of the egg» on the living mass and the reproductive qualities of chickens of meat crosses and the quail of meat breeds.Materials and methods. The selection was carried out along egg production and mass of eggs and additionally on the average small diameter of 5 eggs by value of ≥0.5σ from the average for the herd, while the evaluation on the basis of the «small diameter of the egg» was carried out in chickens aged 238 days of life, quails — 70 days of life. Calculated the average for each female and the average for the herd. For further reproduction, chickens carrying eggs with a small egg diameter ≥0.5σ from the average for the herd. Studies were held in SibNIP on quail and on the courses.Results. In the initial period of the egg laying, the individual variability of the small diameter of the egg — more than 10% (in the future, the figure decreased). The close correlation rate of the small egg diameter in the first half of the egg laying with such at the end of the bird's operation period was revealed. It has been established that the large diameter of the egg has a positive reliable connection with a lively mass, but negative with egg production. The reliable correlation rate of the small diameter of the egg with a live weight at a 42-day age, as well as with the derivation of eggs. The inheritance coefficients of the small diameter of the egg are comparable to the inheritance coefficients of the mass of eggs and significantly exceed those for a large diameter of the egg. The selection according to the small diameter of the eggs by ≥0.5σ from the average for the herd led to the fact that the chickens of the experimental groups reliably exceeded the live weight in the SB level of 1.57%, in the line G8 — by 1.35%. The superiority of a lively mass of quail of experienced groups was more pronounced than that of the chickens: the Pharaoh breed — by 4.15%, the Texas white breed is 4.22%. In relation to the derivation of eggs, a similar trend was traced. The derivation of eggs in quails of experienced groups was more than 4.59–4.98%; Country, respectively, 4.57–5.22%. Egg production of females of comparable groups of both chickens and quail was almost on the same level, and the difference was unreliable.Conclusion. It was established that a new method of breeding the poultry of the meat direction of productivity allows without decreasing egg production to increase the living mass of chickens of meat crosses by 1.5%, rewinds of meat breeds — by 4%, the derivation of eggs, respectively, by 4–5%. The method is intended for early prediction of females productivity during breeding selection.


NANO ◽  
2017 ◽  
Vol 12 (04) ◽  
pp. 1750045
Author(s):  
Jun-Xing Pan ◽  
Yu-Qi Guo ◽  
Yu-Fang Han ◽  
Min-Na Sun ◽  
Jin-Jun Zhang

Computer simulation is carried out for investigating the effect of nanoparticles on diblock copolymer morphology under cylindrical confinement. The phase diagrams of polymer nanocomposites with nanoparticle-block wetting strength and concentration of nanoparticles are obtained in different nanopores. In small diameter nanopore, there is almost no influence of nanoparticles on the diblock copolymer morphology because of the stronger confinement effect; in middle diameter nanopore, the system can self-assemble into various novel structures due to the interaction between confinement effect and nanoparticles effect; in large diameter nanopore, due to the stronger effect of nanoparticles, a disorder-order-disorder phase transition occurs with the wetting strength and concentration of nanoparticles increasing. This result can be useful in designing new nanocomposites with advanced electrical conductivity and/or mechanical strength.


2008 ◽  
Vol 4 (4) ◽  
pp. 307-317 ◽  
Author(s):  
Alexander Gow ◽  
Jerome Devaux

The insulative properties of myelin sheaths in the central and peripheral nervous systems (CNS and PNS) are widely thought to derive from the high resistance and low capacitance of the constituent membranes. Although this view adequately accounts for myelin function in large diameter fibers, it poorly reflects the behavior of small fibers that are prominent in many regions of the CNS. Herein, we develop a computational model to more accurately represent conduction in small fibers. By incorporating structural features that, hitherto, have not been simulated, we demonstrate that myelin tight junctions (TJs) improve saltatory conduction by reducing current flow through the myelin, limiting axonal membrane depolarization and restraining the activation of ion channels beneath the myelin sheath. Accordingly, our simulations provide a novel view of myelin by which TJs minimize charging of the membrane capacitance and lower the membrane time constant to improve the speed and accuracy of transmission in small diameter fibers. This study establishes possible mechanisms whereby TJs affect conduction in the absence of overt perturbations to myelin architecture and may in part explain the tremor and gait abnormalities observed in Claudin 11-null mice.


2012 ◽  
Vol 6 (1) ◽  
pp. 33-37
Author(s):  
Changbing Chen

With the increasing volume demand of silos, squat silo diameters are bigger and bigger. However, present wall pressure computation methods are mostly based on small diameter silos. To solve this problem, systematical research on the wall pressure in squat silos is of great importance. For now, in the Chinese code the wall pressure computation methods are based on the limit equilibrium theory to be calculated, which define the orientation of the failure plane in the bulk solid within the silo. The rupture angle is a key parameter to silos’ wall pressure. Therefore the value and direction of rupture angle are researched by theoretical method in this paper, which has heavy significance and provide an important basis for the large diameter silo design.


2016 ◽  
Vol 1 ◽  
Author(s):  
Dede Djuhana

<p class="TTPAbstract">In this study, we have investigated the LSPR spectra of the silver nanoparticles (Ag-NPs) coated by polyvinyl alcohol (PVA) by means of a numerical study using Bohren-Huffman-Mie (BHMie) approximation. The LSPR of Ag-NPs shifted to red-shift as the diameter size of Ag-NPs and the thickness of PVA increased. The peak of the LSPR spectra exponentially increased as the thickness increased. Interestingly, there have three characteristic of the LSPR spectra, small, intermediate, and large diameter. In small diameter, the dipole resonant mode contributed to the LSPR spectra while in large diameter, the LSPR spectra originated from the quadrupole resonant mode. In contrast to intermediate diameter, the LSPR spectra originated from the competition between the dipole and the quadrupole mode. For this reason, at small and large diameter the LSPR peak has one peak and increased then until a certain thickness showed constant. Different at intermediate diameter, the LSPR peak appeared more one peak with major peak increased then until a certain thickness trend to decrease and minor peak followed at small diameter behavior.</p>


Sign in / Sign up

Export Citation Format

Share Document