plastic sphere
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Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3493
Author(s):  
Maria Montserrat Rivera del Alamo ◽  
Tiina Reilas ◽  
Karolina Lukasik ◽  
Antonio M. Galvão ◽  
Marc Yeste ◽  
...  

Intrauterine devices (IUDs) are used in mares to suppress oestrous behaviour, but the underlying mechanism is yet to be elucidated. The presence of an embryo or an IUD prevents cyclooxygenase-2 (COX-2) and, subsequently, prostaglandin (PG) release and luteolysis. However, inflammation may also be involved. Endometrial inflammatory markers in uterine lavage fluid were measured on Day 10 (EXP 1, n = 25) and Day 15 (EXP 2, n = 27) after ovulation in inseminated mares, non-pregnant or pregnant, and in mares in which a small plastic sphere had been inserted into the uterus 4 (EXP 1) or 3 days (EXP 2) after ovulation. Uterine lavage fluid samples were analysed for nitric oxide (NO), prostaglandin E2 (PGE2) (only Exp. 1), prostaglandin F2α (PGF2α), inhibin A and cytokines, and blood samples for progesterone and oestradiol. On Day 10, the concentration of PGF2α was lower (p < 0.05) in the IUD group than in pregnant mares. The concentration of the modulatory cytokine IL-10 was significantly higher in the IUD group in comparison to non-pregnant mares, and inhibin A was significantly higher in IUD mares than in the pregnant counterparts on Day 15. The results suggest that the presence of IUD causes endometrial inflammation which is at a resolution stage on Day 15.


2021 ◽  
Author(s):  
Yanchao Chai

Abstract More and more researches about microplastics (MPs) have been emerging, as the environmental MPs are detected ubiquitously. Various kinds of MPs have been added heavily as exogenous pollution in toxicological experiments. This perspective is intended to figure out utilization situation of MPs in laboratory and discrepancies between the choice of experiment material and environmental composition of MPs. Here we show, the total number of MPs utilized in 204 articles could be equivalent to that contained in 1015 kg dry wastewater treatment sludge, or comparable to the total existing mass in 600 km− 2 South Pacific subtropical gyre. This means that laboratory could be becoming a potential hotspot of MPs pollution as there is no criterion aiming at treatment of MPs-rich experiment waste. In addition, commercial Polystyrene (PS) microsphere with size less 1 µm was one popular experiment material, which is inconsistent with predominant composition of environmental MPs. That probably overestimate the adverse outcome of MPs as these purchased plastic sphere lack representativeness for actual environmental MPs. This work would shed light on the control and calibration of choice of MPs material in the future research.


2018 ◽  
Vol 68 (5) ◽  
pp. 500-504 ◽  
Author(s):  
Praveen Kumar B ◽  
Bhupender Rawal ◽  
KM Rajan

Ultimate properties of a porous ceramic is highly process dependent. In this study, prevalent porous ceramics fabrication methods (Freeze casting, Foam reticulation and Burnable Plastic Sphere (BURPS) method) have been compared by fabricating the porous lead zirconate titanate (PZT) based piezoelectric ceramics. Field Emission Scanning electron microscopy (FESEM) studies were carried out to study the pore size and distribution of the ceramics. Hydrostatic co-efficients increased tremendously on incorporation of porosity which led to Hydrostatic Figure of Merit of 7480 in Foam reticulation samples (porosity 86%). The three dimensionally interconnected networks in the freeze casted samples led to lowest acoustic impedance (6 MRayls) despite not having the lowest density.


2016 ◽  
Vol 723 ◽  
pp. 363-368 ◽  
Author(s):  
P.M. Ogar ◽  
D.B. Gorokhov

The paper is devoted to the definition of the deformation during indentation of the sphere and its relationship with the tensile deformation. Proposed by different authors methods of determining the deformation of the contact are considered. The results of their researches may vary significantly. It is shown that in the last decade to determine the deformation, the finite element analysis taking into account the "sink-in/pile-up", i.e. an elastic sinking in and plastic piling up of the material on the edges of the indent during the indentation process is widely used. The purpose of this research is to determine the relationship between tension deformation and sphere indentation deformation with taking into account the last achievements in the field of finite-element modeling of elastic-plastic sphere indentation. It is considered two methods of determining of deformation. One uses the equation proposed by S.I. Bulychev, in which the Mayer’s index is determined from the results of finite element analysis. The second method use the energy concept of hardness. It is based on the assumption that within the range of uniform deformation during uniaxial tension and during sphere indentation, the same energy is consumed to the plastic displacement of the part of the material volume out of limits of initial volume. They have close results. The corresponding graphic relations are shown.


2016 ◽  
Vol 95 ◽  
pp. 132-138
Author(s):  
Wenping Song ◽  
Longqiu Li ◽  
Andrey Ovcharenko ◽  
Frank E. Talke

2014 ◽  
Vol 32 (4) ◽  
pp. 549-556 ◽  
Author(s):  
M. Temporal ◽  
B. Canaud ◽  
W.J. Garbett ◽  
R. Ramis

AbstractA spherical target irradiated by laser beams located at 49o and 131° with respect to the polar axis has been considered. The illumination model has been used to evaluate the irradiation non-uniformity assuming circular and elliptical super-Gaussian laser intensity profiles and the irradiation scheme has been optimized by means of the polar direct drive technique. A parametric study has been performed providing the irradiation non-uniformity as a function of the polar direct drive displacement and of the laser intensity profile parameters. Moreover, two-dimensional axis-symmetric hydrodynamic simulations have been performed for a plastic sphere irradiated by laser beams characterized by a constant flat temporal power pulse. In these simulations, the front of the inward shock wave has been tracked providing the time-evolution of any non-uniformity. The results provided by the two methods — illumination model and hydrodynamic data — have been compared and it is found that the illumination model reproduces the main behavior exhibited by the hydrodynamic data. The two models provide compatible values for the optimum polar direct drive parameter and similar optimal super-Gaussian profiles.


2013 ◽  
Vol 61 ◽  
pp. 120-128 ◽  
Author(s):  
Xi Shi ◽  
Aizhong Wu ◽  
Changming Zhu ◽  
Shaoxing Qu

Author(s):  
Wenping Song ◽  
Andrey Ovcharenko ◽  
Longqiu Li ◽  
Guangyu Zhang ◽  
Frank E. Talke

Transient thermo-mechanical contact between a rigid sphere sliding over an elastic-plastic sphere with a larger radius is studied using finite element analysis. Plastic deformation and temperature rise in the contact zone between the two spheres are investigated.


2012 ◽  
Vol 472-475 ◽  
pp. 1693-1697 ◽  
Author(s):  
Nasrul Amri Mohd Amin ◽  
Frank Bruno ◽  
Martin Belusko

The utilisation of phase change material (PCM) for thermal energy storage (TES) can significantly enhance the energy savings achievable with renewable thermal systems. Sphere based packed bed systems have been used as TES for many years. However, due to the thermal resistance within these systems, the heat transfer is limited and not all the PCM can be used effectively. This study focuses on heat transfer enhancement options for single PCM sphere in a TES system. An experimental investigation has been conducted using water as the PCM. The thermal performance of plain plastic sphere containing PCM has been compared to plastic sphere encapsulated with conducting pins. The heat transfer rate of the sphere with conducting pins was more than 34% that of the sphere without pins.


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