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A new process of activating sizing film free (removed sizing) carbon fiber (SFF-CF) mats directly with electron beam irradiation (EBI) under oxygen-rich nitrogen gas prior to lamination assembly and hot-press was found to increase bending strength of CFRTP (CF reinforced thermoplastic polypropylene (PP)) interlayered composite composed of 3 SFF-CF mats between 4 PP sheets, [PP]4[SFF-CF]3. The hot-press fabrication was performed under 4.0 MPa at 473 K for 1 min. Experimental results showed optimal condition of 0.22 MGy-EBI under 2,000 ppm-O2-rich, protective N2 atmosphere improved bending strength, σb at all accumulative probabilities, Pf over that of untreated. This could be explained by maximum number of the strong covalent bonds of CF:C:C:PP and oxygen assisted CF:C:O:C:PP bonds adhering bare SFF-CF surface to PP, instead of the weak intermolecular bonding of CF(H2O, N2, O2)PP of untreated. The optimal concentration of O2 molecules together with the EBI probably purified the SFF-CF surface simultaneously generating dangling bonds, which already naturally exist in SFF-CF as evidenced by the highest intensity ESR peak whose inflection point was at B = 323 mT. This, along with attaching O groups to the SFF-CF surface can explain the increased SFF-CF to PP adhesion sites and bending strength increase. Fracture analysis showed the optimum condition prevented ply delamination and reduced damage area along sample length appearing to increase cohesion between the difficult to adhere thermoplastic PP and SFF-CF plies to take on higher loads. Although bending strength was increased, carefulness is always highly recommended when investigating unsized CF composites.

The psychoactive plant Salvia divinorum has long been used medicinally by Indigenous people from southern Mexico, the only place where it is endemic, and is now studied by pharmaceutical researchers. I analyze competing ways the two groups "make medicine" with salvia, attending simultaneously to material/embodied and semiotic/linguistic dimensions of those practices. I introduce two concepts - stripping and enrobing - to show that differences in how the groups interact with salvia have ethical and political consequences. Those repercussions matter because salvia is but one of many plants important to marginalized groups whose ties to them are threatened by international medical interests.

Bird strike, volcanic rock, hailstones, micrometeoroids, or space debris can cause damage to aircraft and space vehicles, therefore their composite materials must have high impact resistance to maximize safety. In a 55% wt. CaCO3 compression molded short glass fiber polyester GFRP-BMC (bulk molded compound), shortening the nominal 6.4 mm fiber length formulation, by 30 min extended mixing, to 0.44 mm was found to increase Charpy impact values, auc, without a change in the compression molding equipment. Specimens were cut from square panels in a spiral configuration in conformity with ASTM D 6110-02 for orthotropic panels, the flow direction approximately radially outward from the charge. At a median-fracture probability of Pf = 0.50, extended mixing improved auc by 29%, from 7.43 to 9.59 kJm−2, and for each solidification texture angle, namely, 0 to 90 (random), 71, 45 and 18 deg, the auc increased by 25% (6.26 to 7.86 kJm−2), 18% (9.36 to 11.07 kJm−2), 35% (7.68 to 10.37 kJm−2), and 20% (6.96 to 8.36 kJm−2), respectively. This strengthening can be explained by an increased number of thermal compressive stress sites between the glass fiber and matrix due to a difference in the coefficient of thermal expansion (CTE) during cool-down, and shrinkage, with an increased number of spaces between fibers, |Sf| from 217 to approximately 2950 per mm3, enhancing impact energy.

Impact by hailstone, volcanic rock, bird strike, or also dropping tools can cause damage to aircraft materials. For maximum safety, the goal is to increase Charpy impact strength (auc) of a carbon-fiber-reinforced thermoplastic polyphenylene sulfide polymer (CFRTP-PPS) composite for potential application to commercial aircraft parts. The layup was three cross-weave CF plies alternating between four PPS plies, [PPS-CF-PPS-CF-PPS-CF-PPS], designated [PPS]4[CF]3. To strengthen, a new process for CFRP-PPS was employed applying homogeneous low voltage electron beam irradiation (HLEBI) to both sides of PPS plies prior to lamination assembly with untreated CF, followed by hot press under 4.0 MPa at 573 K for 8 min. Experimental results showed a 5 kGy HLEBI dose was at or near optimum, increasing auc at each accumulative probability, Pf. Optical microscopy of 5 kGy sample showed a reduction in main crack width with significantly reduced CF separation and pull-out; while, scanning electron microscopy (SEM) and electron dispersive X-ray (EDS) mapping showed PPS adhering to CF. Electron spin resonance (ESR) of a 5 kGy sample indicated lengthening of PPS chains as evidenced by a reduction in dangling bond peak. It Is assumed that 5 kGy HLEBI creates strong bonds at the interface while strengthening the PPS bulk. A model is proposed to illustrate the possible strengthening mechanism.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern have emerged and may pose a threat to both the efficacy of vaccines based on the original WA1/2020 strain as well as to natural immunity induced by infection with earlier SARS-CoV-2 variants. We sought to explore unanswered questions of how mutations in the spike of circulating SARS-CoV-2 variants, which have been shown to partially evade neutralizing antibodies, impact natural and vaccine-induced immunity. We adapted a Syrian hamster model of moderate to severe clinical disease for two variant strains of SARS-CoV-2: B.1.1.7 (α variant) and B.1.351 (β variant). We then assessed the protective efficacy conferred by either natural immunity from WA1/2020 infection or by vaccination with a single dose of the adenovirus serotype 26 vaccine Ad26.COV2.S. Primary infection with the WA1/2020 strain provided potent protection against weight loss and viral replication in lungs following re-challenge with WA1/2020, B.1.1.7, or B.1.351 14 days later. Ad26.COV2.S induced cross-reactive binding and neutralizing antibodies that were reduced against the B.1.351 strain compared with WA1/2020, but nevertheless still provided robust protection against B.1.351 challenge, as measured by weight loss and pathology scoring in the lungs. Taken together, these data support hamsters as a pre-clinical model to study protection against emerging variants of SARS-CoV-2 conferred by prior infection or vaccination.