Experimental study on the energy absorption capability of circular corrugated tubes under lateral loading and axial loading

A new type of energy absorber called an expansion joint (i.e. a corrugated tube) is examined in this research. Several experiments are performed on three types of thin-walled specimen, namely circular tubes, preformed corrugated tubes and complete corrugated tubes, to investigate the energy absorption of steel specimens under different conditions for quasi-static lateral loading and axial loading. For this purpose, some steel specimens were compressed between two rigid platens in the axial direction, and the other specimens were laterally compressed. The preformed corrugated tubes and the complete corrugated tubes were produced by the hydroforming method. In each geometrical group of specimens, several tubes, which have different wall thicknesses, different inner diameters and different lengths and which are either empty or filled with polyurethane foam, were tested. Experiments show that, for a lateral load, the specific absorbed energies of the complete corrugated tubes are higher than those of the corresponding preformed corrugated tubes and circular tubes with the same characteristics. Tests show that, under lateral loading, a complete corrugated tube with a thicker wall and a smaller diameter is the optimum energy absorber system. Therefore, when a circular tube transforms into the corrugated tube, a better energy absorber system with a higher capability is achieved under lateral loading. Also, experiments show that, under axial loading, simple circular tubes with no forming process have higher specific absorbed energies than corrugated tubes do. Corrugated specimens have more controllable plastic deformation and a more regular deformation mode than simple tubes have. Tests under axial loading illustrate that, when the preformed corrugated tubes are filled with polyurethane foam, the specific absorbed energy increases by up to 74%. A comparison of the results on empty and filled specimens shows that, in some cases, the specific absorbed energies of corrugated tubes under lateral loading are higher than the specific absorbed energies of circular tubes under axial loading. This means that, by shaping the circular tubes into preformed corrugated tubes and complete corrugated tubes via the hydroforming process, a new thin-walled structure with a high specific absorbed energy during the lateral compression process is introduced

Analytical and experimental studies on stress capacity with modified wood members under combined stresses

The stress capacity of joints made of modified wood members under loading can be affected by design of joints and type of adhesive. Hence, these factors were addressed in this study by assessment of stress capacity variations in corner joints under diagonal applied compressive load induced combined stresses. The joints with mitered and butted design were constructed by application of epoxy and polyvinyl acetate (PVAc) adhesives from furfurylated wood samples with two weight percentage gains (WPGs), i.e., 20% as low level and 60% as high level. Results indicated that stress capacity in both corner joints was not significantly decreased with increasing polymerization of furfuryl alcohol (FA) in wood. Despite the high compression strength in mitered joint, the induced compression stresses were low in comparison with butted joint. The stress capacity in mitered joint bonded with epoxy adhesive enhanced with increasing the level of furfurylation. This was true for shear stress parallel to grain as well. Generally, it could be concluded that mitered joint made of furfurylated members and bonded with epoxy adhesive would be stronger than other corner joints

Building-Integrated Photovoltaic/Thermal (BIPVT): LCA of a façade-integrated prototype and issues about human health, ecosystems, resources

Building-Integrated Photovoltaic/Thermal (BIPVT) technology offers multiple advantages; however, these types of installations include materials such as Photovoltaic (PV) cells and metals which considerably influence BIPVT environmental impact. Therefore, there is a need to evaluate BIPVT environmental profile, for instance by means of Life Cycle Assessment (LCA). In light of the issues mentioned above, the present article is an LCA study that assesses the environmental performance of a BIPVT prototype that has been developed and patented at the Ulster University (Belfast, UK). The investigation places emphasis on material manufacturing, based on Cumulative Energy Demand (CED), Global Warming Potential (GWP), ReCiPe, Ecological footprint and USEtox. The results show that according to all the adopted methods/environmental indicators and based on primary materials, the PV cells and the two vessels (steel) are the components with the three highest impacts. Scenarios which include recycling of steel, plastics and brass (landfill for the other materials has been assumed), based on CED, GWP 100a and ReCiPe endpoint, have been examined. It was found that steel recycling offers a considerable impact reduction, ranging from 47% to 85%. Furthermore, the impact of the proposed BIPVT module per m2 of thermal absorber has been calculated. The results, based on primary materials, show 4.92 GJprim/m2 and 0.34 t CO2.eq/m2 (GWP 100a). In addition, according to USEtox/ecotoxicity, USEtox/human toxicity-non-cancer (scenario based on primary materials), the PV cells present the highest contributions to the total impact of the module: 55% in terms of ecotoxicity and 86% concerning human toxicity/non-cancer. A comparison with literature is provided. Moreover, a separate section of the article is about factors which influence BIPVT environmental profile, discussing parameters such as the storage materials and the end-of-life management.The authors would like to thank “Ministerio de Economía y Competitividad” of Spain for the funding (grant reference ENE2016-81040-R)

Analytical and experimental studies on stress capacity with modified wood members under combined stresses

The stress capacity of joints made of modified wood members under loading can be affected by design of joints and type of adhesive. Hence, these factors were addressed in this study by assessment of stress capacity variations in corner joints under diagonal applied compressive load induced combined stresses. The joints with mitered and butted design were constructed by application of epoxy and polyvinyl acetate (PVAc) adhesives from furfurylated wood samples with two weight percentage gains (WPGs), i.e., 20% as low level and 60% as high level. Results indicated that stress capacity in both corner joints was not significantly decreased with increasing polymerization of furfuryl alcohol (FA) in wood. Despite the high compression strength in mitered joint, the induced compression stresses were low in comparison with butted joint. The stress capacity in mitered joint bonded with epoxy adhesive enhanced with increasing the level of furfurylation. This was true for shear stress parallel to grain as well. Generally, it could be concluded that mitered joint made of furfurylated members and bonded with epoxy adhesive would be stronger than other corner joints

Physiological responses of white mustard grown in Zn-contaminated soils

Introducing zinc (Zn) biofortified vegetables capable to thrive on Zn-polluted soils might simultaneously solve both the problems of dietary Zn deficiency and environmental Zn pollution. White mustard (Sinapis alba L.) is known to thrive on soils with high Zn concentrations, thus we aimed to determine to what extent it has physiological characteristics close to known Zn hyperaccumulators for possible use of this species in phytoremediation efforts and production of Zn-biofortified crops. To achieve this, in a pot experiment plants were grown for 7 weeks in soils with normal (25.5 mg kg�1) and excess (500 and 1000 mg kg�1) Zn concentrations and assessed for metal accumulation, enrichment, translocation and tolerance. Zn accumulated mainly in shoots (861 mg kg�1) with translocation factor of 2.5 in parallel with enhanced root H+-ATPase activity but the plant Zn bioconcentration factors were less than one. Excess soil Zn increased plant biomass and activities of some reactive oxygen species scavenging enzymes without any effects on root lipid peroxidation or leaf chlorophyll contents. Despite lack of criteria for a true Zn hyperaccumulator, white mustard exhibited significant Zn trans-location capacity with tolerance to toxic Zn concentrations in tissues as reflected from its efficient antioxidant metabolism, unaltered photosynthetic pigments under excess Zn and high aboveground biomass similar to some Zn hyperaccmulators. Accordingly, the cultivation of this species has the dual advantages of phytoremediating Zn-contaminated soils and producing Zn-biofortified vegetables. © 2020, Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków

Transcriptome alterations of radish shoots exposed to cadmium can be interpreted in the context of leaf senescence

Till now few transcriptome studies have described shoot responses of heavy metal (HM)-sensitive plants to excess Cd and still a unifying model of Cd action is lacking. Using RNA-seq technique, the transcriptome responses of radish (Raphanus sativus L.) leaves to Cd stress were investigated in plants raised hydroponically under control and 5.0 mg L�1 Cd. The element was mainly accumulated in roots and led to declined biomass and photosynthetic pigments, increased H2O2 and lipid peroxidation, and the accumulation of sugars, protein thiols, and phytochelatins. Out of 524 differentially expressed genes (DEGs), 244 and 280 upregulated and downregulated ones were assigned to 82 and 115 GO terms, respectively. The upregulated DEGs were involved in osmotic regulation, protein metabolism, chelators, and carbohydrate metabolisms, whereas downregulated DEGs were related to photosynthesis, response to oxidative stress, glucosinolate, and secondary metabolite biosynthesis. Our transcriptome data suggest that Cd triggers ROS production and photosynthesis decline associated with increased proteolysis through ubiquitin�proteasome system (UPS)- and chloroplast-proteases and in this way brings about re-mobilization of N and C stores into amino acids and sugars. Meanwhile, declined glucosinolate metabolism in favor of chelator synthesis and upregulation of dehydrins as inferred from transcriptome analysis confers shoots some tolerance to the HM-derived ionic/osmotic imbalances. Thus, the induction of leaf senescence might be a major long-term response of HM-sensitive plants to Cd toxicity. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature