Stress rupture of SiC/SiC composite tubes under high-temperature steam

SiC-fiber–reinforced SiC matrix composite cladding for light water reactor fuel elements must withstand high-temperature steam oxidation in a loss-of-coolant accident scenario (LOCA). Current composite designs include an outer monolithic SiC layer, in part, to increase steam oxidation resistance. However, it is not clear how such a structure would behave under high-temperature steam in the case when the monolithic layer cracks and carbon interphases and SiC fibers are exposed to the environment. To fill this knowledge gap, stress-rupture tests of prototypic SiC composite cladding at 1000°C under steam and inert environments were conducted. The applied stress was ∼120 MPa, which was beyond the initial cracking stress. The failure lifetime under steam was 400–1300 s, while 75% of the composite specimens did not fail after 3 h of total exposure under inert gases. Microstructural observations suggest that steam oxidation activated slow crack growth in the fibers, which led to failure of the composite. The results from this study suggest that stress rupture in steam environments could be a limiting factor of the cladding under reactor LOCA conditions.     

Polymeric Nanoparticles as a Self-Adjuvanting Peptide Vaccine Delivery System: The Role of Shape

Antigens incorporated in subunit vaccines are typically poorly immunogenic, so a strong immunostimulant (adjuvant) and/or delivery system is required to boost immunogenicity. In this work, the various functional polymer nanostructures, that is, rods, worms, spheres, and tadpoles are used to develop potent peptide antigen delivery systems. The antigen PADRE-J8 (PJ8), derived from Group A Streptococcus (GAS) M-protein, is either physically mixed or chemically conjugated to polymeric nanoparticles of different shapes. The physical mixture of polymeric nanoparticles and antigen is more effective in inducing antibody production than their chemical conjugates. Moreover, rod-shaped polymeric nanoparticles in physical mixture with PJ8 elicited higher and more opsonic antibody titers than powerful complete Freund's adjuvant (CFA)-adjuvanted antigen. Herein, for the first time it is demonstrated that a) the block copolymer, in nanoparticle form, can act as an immune adjuvant, b) nanoparticle shape plays a crucial role in their immunogenicity, and c) antigen conjugation is not required, nor is antigen encapsulation or absorption.     

Simulation of high-concentration self-interactions for monoclonal antibodies from well-behaved to poorly-behaved systems

Attractive self-interactions of therapeutic proteins are linked to problematic solution behaviors at high protein concentrations such as reversible or irreversible aggregation, high viscosity, opalescence, phase separation, and low solubility. Prediction of attractive self-interactions early in development can improve the processes of formulation development and candidate selection. To that end, a coarse-grained model with explicit representation of charged sites was used to accurately predict a broad range of protein self-interactions at high protein concentrations (up to 160 mg/ml) for multiple monoclonal antibodies and formulations, including strong electrostatic attractions, with static light scattering measurements at low protein concentrations as the only experimental input. In addition, Mayer-weighted electrostatic energies for charged residues from these simulations can contribute to understanding of electrostatic interactions and guide the development of protein variants.     

TENET: a new hybrid network architecture for adversarial defense

International Journal of Information Security - Deep neural network (DNN) models are widely renowned for their resistance to random perturbations. However, researchers have found out that these...     

Image Analysis of Gluten-free Breads Prepared with Chestnut and Rice Flour and Baked in Different Ovens

In this study, the effects of chestnut flour and xanthan–guar gum blend–emulsifier DATEM mixture addition on macro- and microstructure of rice breads baked in conventional and infrared–microwave combination ovens were investigated by using the images obtained by a scanner and scanning electron microscopy (SEM). Pore area fraction, pore size distribution, and roundness values of pores were determined. The highest pore area fraction values were obtained in breads prepared by replacement of 46 % of rice flour with chestnut flour containing xanthan–guar gum blend–DATEM mixture and baked in an infrared–microwave combination oven. On the other hand, rice breads containing no additives or chestnut flour had the lowest pore area fraction values. Infrared–microwave combination baking increased both pore area fraction values and total number of pores. Infrared–microwave combination baking caused approximately 23–28 % increase in number of the small pores (0–5 mm²) in rice breads and 71 % increase in number of the large pores (>10 mm²) in chestnut–rice breads. The fiber content and larger starch granules of chestnut flour contributed towards the stabilization of gas bubbles resulting in better crumb structure. More homogenous pore distributions were observed when additives and an infrared–microwave combination oven were used. When microstructure of gluten-free breads was investigated, it was seen that starch granules in chestnut–rice breads baked in an infrared–microwave combination oven did not disintegrate completely.     

Synthesis,structural characterization,and antiproliferative/cytotoxic effects of a novel modified poly(maleic anhydride-co-vinyl acetate)/doxorubicin conjugate

Polymer Bulletin - Drug carrier, poly(maleic anhydride-co-vinyl acetate) (MAVA or poly[MA-co-VA]) copolymer, was traditionally synthesized by free radical chain polymerization reaction, in methyl...     

Investigating the effect of production process of ball mill refiner on some physical quality parameters of compound chocolate: response surface methodology approach

Chocolate compound was produced using ball mill refiner, and the effect of agitator shaft speed and refining time on the physical quality parameters (particle size, colour and steady‐state rheology) of compound chocolate was determined using response surface methodology. The shaft speed and refining time range were selected between 40–60 r.p.m. and 10–30 min, respectively. Determination coefficient of the models established for particle size, Newtonian viscosity and colour parameters (brightness, chroma and hue angle) were found to be very close to unity. Increasing shaft speed and time induced a reduction in particle size and an increase in viscosity of the samples. Temperature sweep test was also performed, and the obtained data were successfully fitted to Arrhenius equation to calculate the corresponding parameters representing temperature dependency of the compounds. The results highlighted that the establishment of such models can provide essential information in terms of optimisation of production processes regarding usage purpose of the compound chocolate.     

Dyeing,fastness, and cytotoxic properties,and phenolic constituents of Anthemis tinctoria var. tinctoria (Asteraceae)

The present study focused on dyeing, fastness, cytotoxic properties, and phenolic constituents of various types of fabrics including viscose, cotton, wool, and polyester-viscose blended fabrics with different parts of Anthemis tinctoria var. tinctoria. Comparative study was carried out between ethanol and aqueous extracts of stem, flower, and root of the plant in terms of phenolic constituents, cytotoxic activity, and dyeing properties. It was found that the quantity of phenolic constituents of ethanol and aqueous extracts was quite different. All parts of the plant extract show 0% cytotoxicity except ethanol extract of the root. All the extracts exhibit better cytotoxic activity than the standard cancer drug 5-Florouracil. Ethanol and water extracts of A. tinctoria var. tinctoria plant were used to dye fabrics, but only the water extract displayed dyeing properties. Best color strength value (K/S = 9.19) was obtained with aqueous extract of the stem in the presence of alum mordant for cotton fabrics.     

Heat pipes thermoelectric solar collectors for energy applications

This study investigates the load characteristics of heat pipe thermoelectric solar collector (HPTSC) in practice. Heat pipe thermoelectric solar collector converts the heat generated by the Sun directly into electrical energy and produces hot water as well. The maximum power in HPTSC is obtained when the internal resistance of the thermoelectric module is equal to the load resistance. It has been observed to be possible to produce both hot water and electricity by improving available solar collectors or producing new generation HPTSC. While it is possible to generate an electrical power of 160 W from a HPTSC of one square meter using the thermoelectric method, the power produced with an average photovoltaic panel with the same area is only 132 W. Accordingly, HPTSC is a superior alternative not only to available solar collectors, but also to available PV panels. HPTSC, involving three different technologies, is environmentally friendly and certainly a product that allows for more efficient use of solar energy.