Rubber composites with excellent radiation shielding and flexibility are extremely important to personal protective equipments (PPEs) for protecting workers from radiation hazards, especially for ...mixed radiations. It is, however, challenging to achieve uniform dispersion of fillers and good compatibility of the interfaces in highly‐filled rubber composites that are closely related to their physical properties. In this article, lead borate@polydopamine (PBO@PDA) core–shell particles are chemically bonded with silicone rubber (SR) for co‐shielding of neutron and γ‐rays. Uniform dispersion of the core–shell particles and good compatibility of the interfaces give rise to enhanced flexibility of the rubber composites. Particularly, the SR composite with 40 wt% PBO particles displays increases of 106% in elongation at break and 490% in tensile strength to neat SR. Furthermore, the mass attenuation coefficient of γ‐rays (105 KeV) reaches 2.35 and the thermal neutron absorption rate (0.025 eV) of is 76.9%. This work takes into account the balance between radiation shielding and flexibility of rubber composites, which provides a facile strategy to fabricate excellent integrated properties of flexible materials for shielding mixed neutron and γ‐rays.
Lead borate micro–nano particles chemically bonded with silicone rubber are used to coordinately shield thermal neutrons and gamma rays.
Flexible materials with excellent radiation shielding and flexibility are essential to the personal protective equipments (PPEs) for protecting workers from nuclear radiations. However, it is an ...enormous challenge to obtain the desired materials since high loading filler in polymer nanocomposites usually promotes radiation shielding while restrains its flexibility. Here, a facile “thiol‐ene click” means is applied to chemically bond high loading boron nitride (BN) nanoparticles with silicone rubber (SR) in SR/BN nanocomposites for thermal neutron shielding. Uniform dispersion of BN nanoparticles and good compatibility of interfaces in the nanocomposites with high loading filler lead to increased flexibility instead of decrease. In particular, the nanocomposite with 40 wt% BN displays 911% of elongation at break that is about 50% enhancement to that of neat SR. Furthermore, higher loading BN in the nanocomposites means better thermal neutron shielding. Namely, enhanced thermal neutron shielding and flexibility is achieved at SR/BN nanocomposite with 40 wt% BN. The present work provides a facile strategy towards superior integrated performance of flexible materials for radiation shielding, such as wearable devices.
Chemically bonding BN nanoparticles with silicone rubber contributes to good interfacial compatibility in highly‐filled polymer nanocomposites, leading to enhanced radiation shielding and flexibility.
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•Extraction, purification and SAS were adopted to produce high purity fucoxanthin.•RSM method was used to optimize the SAS experiments.•The SAS pressure affected the purity of ...fucoxanthin more than did the injection time.
This study examines the supercritical anti-solvent (SAS) crystallization of chromatographically purified fucoxanthin from the micro-algal species of Hincksia mitchellae P.C. Silva. Two sequential medium-pressure column fractionations where the eluent was a mixed solvent of n-hexane and acetone yielded 719.8 milligrams of fucoxanthin per gram of the fraction. The mean recovery of the two-column fractionation was 85.6%. A few experiments on SAS precipitation from diethyl ether solution were performed at various pressures, injection time, temperature, feed flow rate and concentrations, thereby providing information on the effects of pressure and injection time on the purity of the resultant fucoxanthin. A central-composite response surface method was used to optimize the SAS experiments used to produce the micro-sized particulates containing 876.9mg of fucoxanthin per gram. The recovery of fucoxanthin by this SAS process was 98.3%. The SAS pressure affected the purity of fucoxanthin more than did the injection time.
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► Higher concentration of triglycerides was obtained using supercritical carbon dioxide extraction of de-shell Jatropha curcas L. seeds. ► Under an optimum pressure of 350bar, a ...temperature of 325K and a solvent to solid ratio of 82, concentration and recovery of triglycerides were 936.2mg/g and 98.1%, respectively. ► The quality of SC-CO2 extracted oil was superior to that of Soxhlet n-hexane extracted oil, providing an alternative method for biodiesel production.
This study examined the use of supercritical carbon dioxide (SC-CO2) in the extraction of triglycerides from de-shelled Jatropha curcas L. seeds. A central composite response surface methodology (RSM) was employed to evaluate the effects of pressure, temperature and solvent-to-solid ratio (SSR) on total yield (TY), concentration of triglycerides (CTG) and recovery of triglycerides (RTG). In the experiment, SC-CO2 extraction of 15g ground, de-shelled Jatropha seeds at a CO2 flow rate of 25mL/min was investigated under various pressure (250–350bar), temperature (313–333K) and SSR (60–100) conditions. The proposed quadratic model well fitted the RSM-designed data, and the statistical analyses showed that both pressure and SSR are important parameters that will significant affect the quality of extracted oil. Under a pressure of 350bar, a temperature of 325K and a SSR of 82, the values of TY, CTG and RTG were 43.0%, 936.2mg/g, and 98.1%, respectively.
Nepenthes mirabilis (Nepenthaceae) is an erect or climbing (0.5-2 m tall) herb distributed in Africa (Madagascar), south and southeast Asia, North Australia and Pacific Islands (Caroline Islands). ...There is only one species in China. It grows in wet and sandy soils places throughout forests, grasslands, swamps, mountains, roadsides, wastelands having altitudes that sea level to 400 m. It has been ranked as a VU (Vulnerable) species in China. Here we report and characterize the complete plastid genome sequence of N. mirabilis in an effort to provide genomic resources useful for its conservation. The complete plastome is 155,755 bp in length and contains the typical structure and gene content of angiosperm plastomes, including two Inverted Repeat (IR) regions of 26,415 bp, a Large Single-Copy (LSC) region of 84,997 bp and a Small Single-Copy (SSC) region of 17,928 bp. The plastome contains 113 genes, consisting of 77 unique protein-coding genes, three pseudogenes, 29 unique tRNA genes, and four unique rRNA genes. The overall A/T content in the plastome of N. mirabilis is 62.8%. Phylogenetic analyses were performed using the entire plastome, including spacers, introns, etc., and we determined that N. mirabilis 32 and Dionaea muscipula were closely related. The complete plastome sequence of N. 33 mirabilis will provide a useful resource for the conservation genetics of this species as 34 well as for the phylogenetic studies in Caryophyllales.
Scurrula notothixoides (Loranthaceae) is a hemiparasitic shrub distributed in forest margins of Southeast Asian countries. Here, we report and characterize the complete plastid genome sequence of S. ...notothixoides in an effort to provide genomic resources useful for the phylogenetic studies for Santalales. The complete plastome is 123,810 bp in length and contains the typical structure and gene content of angiosperm plastomes, including two inverted repeat (IR) regions of 23,101 bp, a large single copy (LSC) region of 71,448 bp and a small single copy (SSC) region of 6160 bp. The plastome contains 88 genes, consisting of 61 unique protein-coding genes, 23 unique tRNA genes and four unique rRNA genes. The overall A/T content in the plastome of S. notothixoides is 62.7%. Phylogenetic analyses were performed using the entire plastome, including spacers, introns, etc. and we recovered that S. notothixoides and Taxillus sutchuenensis was closely related. The complete plastome sequence of S. notothixoides will provide a useful resource for the phylogenetic studies for Santalales.
Polymer composites filled with conductive particles for high dielectric constant (high-κ) have been extensively studied due to their distinct advantages such as good processability, flexibility and ...lightweight. However, to achieve high dielectric constant usually requires high loadings of filler, which may bring conductivity leading to large dielectric loss. Here, insulative CaCO3 is uniformly coated on the surfaces of carbon nanofibers (CNFs) via a facile self-assembly route, resulting in a core-shell structured CaCO3@CNF. Blending it with epoxy resin shows an obvious enhancement in dielectric constant to neat epoxy resin due to the presence of 2.1 wt% CNFs in composite. Importantly, uniform dispersion of the core-shell structure with about 80 nm insulating shell can effectively block electron current. Then reduced dielectric loss and enhanced dielectric constant could occur simultaneously, which is significantly positive to the composites for further electric energy storage.
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•A facile self-assembly of a core-shell structure is provided.•Conductive CNFs is uniformly covered with insulating CaCO3 shell.•The CaCO3@CNF is greatly potential use for polymer dielectrics.
Hydnocarpus hainanensis Merr. is an evergreen tree with a height of 6-12 m and a diameter at breast height of 50 cm. It is distributed in Guangxi, Guizhou, Hainan, South of Yunnan Province of China. ...Here, we report and characterize the complete plastid genome sequence of H. hainanensis in an effort to provide genomic resources useful for promoting its conservation and systematics research. The plastome of H. hainanensis is found to possess a total length 163,330 bp with the typical quadripartite structure of angiosperms, containing two inverted repeats (IRs) of 26,870 bp, a large single copy (LSC) region of 91,510 bp and a small single copy (SSC) region of 18,080 bp. The plastome contains 111 genes, consisting of 78 unique protein-coding genes (seven of which are duplicated in the IR: rps12, rps7, ndhB, ycf2, rpl23, rpl2, and rps19), 29 unique tRNA genes (seven of which are duplicated in the IR, i.e. trnN
GUU
, trnR
ACG
, trnA
UGC
, trnl
GAU
, trnV
GAC
, trnL
CAA
, and trnl
CAU
) and four unique rRNA genes (5S rRNA, 4.55S rRNA, 23S rRNA, and 16S rRNA). The overall A/T content in the plastome of H. hainanensis is 63.70%. The phylogenetic analysis indicated that H. hainanensis is close to Salix rorida within Malpighiales. The complete plastome sequence of H. hainanensis will provide a useful resource for the conservation genetics of the one species as well as for the phylogenetic studies of Achariaceae.
This study examines the supercritical carbon dioxide (SC-CO₂) extraction of oryzanols contained rice bran oil from powdered rice bran. The extraction efficiencies and concentration factors of ...oryzanols, free fatty acids and triglycerides in the SC-CO₂ extracts were determined. With top-flow type SC-CO₂ extraction the total oil yield was 18.1% and the extraction efficiencies of oryzanols and triglycerides were 88.5 and 91.3% respectively, when 2750 g CO₂ was consumed during the extraction of 35 g rice bran powder. The concentration factors of oryzanols and triglycerides in SC-CO₂-extracted oil were higher than in the Soxhlet n-hexane extracted oil. SC-CO₂ extractions indicated that pressure can be used more effectively than temperature to enhance the extraction efficiency and concentration factor of oryzanols. A two-factor central composite scheme of response surface methodology was employed to determine the optimal pressure (300 bar) and temperature (313 K) for increasing the concentration of oryzanols in the SC-CO₂ extracted oil.
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