Benzoxazine resin as an interesting building block for advanced neutrons shields

2021 ◽  
pp. 095400832110218
Author(s):  
Oussama Mehelli ◽  
Mehdi Derradji ◽  
Abdelmalek Habes ◽  
Nour Elislem Leblalta ◽  
Raouf Belgacemi ◽  
...  

The design of lightweight neutrons shields has been restricted for quite some time to the use of the epoxy thermosets as the main building blocks. Meanwhile, the recent developments in the field of polymers suggest otherwise. Indeed, benzoxazine resins have taken the lead over the traditional thermosets in many exigent applications. Therefore, in a vision to introduce newer matrices with better performances and to further expand the applications of the benzoxazine resins into the nuclear field, the neutron shielding efficiency along with the thermal and thermomechanical performances of the neat benzoxazine polymer and its subsequent B4C-reinforced composites were investigated. The neutron shielding measurements were performed using an optimized experimental setup at NUR research reactor, Algiers. The neat benzoxazine polymer displayed almost similar thermal neutrons screening performances than the epoxy with a macroscopic cross-section (Σ) of a 0.724 cm− 1 equivalent to a mean free path (λ) of 0.957 cm. The effect of the particle amount was also studied to maximize the shielding ability of the developed materials. For instance, the benzoxazine composite containing 20 wt.% of B4C displayed the outstanding screening ratio of about 96% for a sample thickness of 13 mm. Finally, the remarkable findings were put into context by providing multifaceted comparisons with the available shielding materials.

2021 ◽  
Author(s):  
Chao Wang ◽  
Zhefu Li ◽  
Mengge Dong ◽  
Lu Zhang ◽  
Jianxing Liu ◽  
...  

<p>Although the various excellent properties and preparation methods of TiB<sub>2</sub>-based composites have been extensively studied, their neutron shielding properties have not received as much attention. In this article, the neutron shielding performance of the previously prepared TiB<sub>2</sub>-Al composite will be studied. The photo neutron source device was used to carry out neutron irradiation tests on test samples with a thickness of 10 mm. The average thermal neutron shielding rate of TiB<sub>2</sub>-based boron-containing composites is 17.55%, and the shielding rate increases with the increase of BN content. The macroscopic cross-section of thermal neutrons of the composites generally shows a stable trend, and when the BN content is 10%, the thermal neutrons macroscopic cross section reaches the maximum value of 7.58cm<sup>-1</sup>. With the increase of the BN content, the thermal neutron fluence rate shows a gradually decreasing trend.</p>


2011 ◽  
Vol 201-203 ◽  
pp. 2767-2771 ◽  
Author(s):  
Zhe Fu Li ◽  
Xiang Xin Xue ◽  
Tao Jiang ◽  
He Yang ◽  
Mi Zhou

Three kinds of low cost shielding materials using boron-containing ores and epoxy as starting materials were developed. The three boron-containing ores consist of natural green ore that is specific in China and the two artificial minerals that are boron-containing iron ore concentrate and boron-rich slag. They were got after natural green ore dressing and separation from blast furnace, respectively. The shielding performance of slow neutron and 60Co γ ray among the three shielding materials were compared. The results show that boron-rich slag as neutron absorber performs relative good slow neutron shielding ability, its macroscopic cross section (Σ) is 0.271cm-1 which is about 1.72 times higher than Lead-Boron Polyethylene B201 whose macroscopic cross section (Σ) is 0.158cm-1. Boron-containing iron ore concentrate/epoxy composite performs relative good 60Co γ ray shielding ability and its linear attenuation coefficient (μ) is 0.0772cm-1. The elements boron and iron that exist as compound in ore are the main reasons to affect the slow neutron shielding performance. The iron element that exists as compound in the ore has the main attribution to 60Co γ ray shielding.


2021 ◽  
Author(s):  
Chao Wang ◽  
Zhefu Li ◽  
Mengge Dong ◽  
Lu Zhang ◽  
Jianxing Liu ◽  
...  

<p>Although the various excellent properties and preparation methods of TiB<sub>2</sub>-based composites have been extensively studied, their neutron shielding properties have not received as much attention. In this article, the neutron shielding performance of the previously prepared TiB<sub>2</sub>-Al composite will be studied. The photo neutron source device was used to carry out neutron irradiation tests on test samples with a thickness of 10 mm. The average thermal neutron shielding rate of TiB<sub>2</sub>-based boron-containing composites is 17.55%, and the shielding rate increases with the increase of BN content. The macroscopic cross-section of thermal neutrons of the composites generally shows a stable trend, and when the BN content is 10%, the thermal neutrons macroscopic cross section reaches the maximum value of 7.58cm<sup>-1</sup>. With the increase of the BN content, the thermal neutron fluence rate shows a gradually decreasing trend.</p>


2017 ◽  
Vol 888 ◽  
pp. 179-183
Author(s):  
Nurazila Mat Zali ◽  
Hafizal Yazid ◽  
Megat Harun Al Rashid Megat Ahmad ◽  
Irman Abdul Rahman ◽  
Yusof Abdullah

In this work, thermoplastic natural rubber (TPNR) composites were produced through melt blending method. Boron carbide (B4C) as filler was added into the polymer blend (TPNR) with different weight percent from 0% to 30% and the effect of different B4C contents on mechanical and thermal neutron attenuation properties of TPNR composites has been studied. The phase formation in composites was analyzed using XRD technique. From the results, it showed that the incorporation of B4C fillers into TPNR matrix has enhanced the macroscopic cross section of the composites, however it lessens the tensile strength. Macroscopic cross section of the composites were increased from 3.34 cm-1 to 14.8 cm-1, while the tensile strength of the composites decreased from 3.79 MPa to 1.06 MPa with increasing B4C from 0 wt% to 30 wt%. B4C diffraction peaks were also increased in intensity with increasing B4C content.


2003 ◽  
Vol 773 ◽  
Author(s):  
C. Tamerler ◽  
S. Dinçer ◽  
D. Heidel ◽  
N. Karagûler ◽  
M. Sarikaya

AbstractProteins, one of the building blocks in organisms, not only control the assembly in biological systems but also provide most of their complex functions. It may be possible to assemble materials for practical technological applications utilizing the unique advantages provided by proteins. Here we discuss molecular biomimetic pathways in the quest for imitating biology at the molecular scale via protein engineering. We use combinatorial biology protocols to select short polypeptides that have affinity to inorganic materials and use them in assembling novel hybrid materials. We give an overview of some of the recent developments of molecular engineering towards this goal. Inorganic surface specific proteins were identified by using cell surface and phage display technologies. Examples of metal and metal oxide specific polypeptides were represented with an emphasis on certain level of specificities. The recognition and self assembling characteristics of these inorganic-binding proteins would be employed in develeopment of hybrid multifunctional materials for novel bio- and nano-technological applications.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Bernhard Mistlberger ◽  
Gherardo Vita

Abstract We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.


2011 ◽  
Vol 241 (10) ◽  
pp. 4152-4157
Author(s):  
A. Tonkunas ◽  
R. Pabarcius ◽  
G. Stankunas ◽  
L. Hutton ◽  
P. Smith ◽  
...  

Nanoscale ◽  
2016 ◽  
Vol 8 (47) ◽  
pp. 19510-19522 ◽  
Author(s):  
Adam Armada-Moreira ◽  
Essi Taipaleenmäki ◽  
Fabian Itel ◽  
Yan Zhang ◽  
Brigitte Städler

This minireview outlines recent developments in droplet microfluidics regarding the assembly of nanoparticles, Janus-shaped and other non-spherical particles, and cargo-loaded particles which could potentially be employed as building blocks in cell mimicry.


Author(s):  
Sergey V. Dorozhkin

There has been much recent activity in the research area of nanoparticles and nanocrystalline materials, in many fields of science and technology. This is due to their outstanding and unique physical, mechanical, chemical and biological characteristics. Recent developments in biomineralization have demonstrated that nano-sized particles play an important role in the formation of the hard tissues of animals. It is well established that the basic inorganic building blocks of bones and teeth of mammals are nano-sized and nanocrystalline calcium orthophosphates (in the form of apatites) of a biological origin. In mammals, tens to hundreds of nanocrystals of biological apatite are found to combine into self-assembled structures under the control of bio-organic matrixes. It was also confirmed experimentally that the structure of both dental enamel and bones could be mimicked by an oriented aggregation of nano-sized calcium orthophosphates, determined by the biomolecules. The application and prospective use of nano-sized and nanocrystalline calcium orthophosphates for clinical repair of damaged bones and teeth are also known. For example, a greater viability and a better proliferation of various cells were detected on smaller crystals of calcium orthophosphates. Furthermore, studies revealed that the differentiation of various cells was promoted by nano-sized calcium orthophosphates. Thus, the nano-sized and nanocrystalline forms of calcium orthophosphates have the potential to revolutionize the field of hard tissue engineering, in areas ranging from bone repair and augmentation to controlled drug delivery devices. This paper reviews the current state of knowledge and recent developments of various nano-sized and nanocrystalline calcium orthophosphates, covering topics from the synthesis and characterization to biomedical and clinical applications. This review also provides possible directions of future research and development.


2016 ◽  
Vol 29 (7) ◽  
pp. 849-856
Author(s):  
Tao Jiang ◽  
Chengzhen Geng ◽  
Hanmei Zhou ◽  
Ai Lu

Two kinds of glass fibers with round (RdGF) and rectangle cross-sections (RcGF) were used to reinforce polyphenylene sulfide (PPS), respectively. In this way, the effect of fiber cross-section shape on rheological and mechanical properties of the composites was studied for the first time. Results showed that the viscosity of the composites reinforced with RcGF was much lower than that of RdGF composites, owing to their higher sensitivity to flow. As a result, PPS/RcGF composites could be injection-molded at high fiber contents. Moreover, RcGF showed a better reinforcing effect on mechanical properties of PPS. So the use of RcGF could better balance the contradiction between processability and reinforcing effect for glass fiber-reinforced composites. Various characterizations were carried out to reveal the reinforcing mechanism. This work demonstrated the importance of fiber cross-section shape on design and production of fiber-reinforced composites.


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