Structural Behavior of Voided Reinforced Concrete Beams Under Combined Moments

The ability of reducing the reinforced concrete beams weights without significantly affecting its structural adequacy especially when combined loads are more eventual, is the aim of present paper. Therefore, the structural behavior of reinforced concrete beams containing air voids and subjected to combined moments of equal bending moment and torsional moment was observed.Five identical beams in external dimensions and internal reinforcement were the specimens of the study. The five beams were divided into two solid, two contain series of plastic balls and one contains a single plastic pipe. The plastic balls and pipe were used to create air voids inside the beams to reduce its concrete amount for economic and environmental considerations. All the beams were tested until failure, but two from its (one solid and one contains plastic balls) were tested under pure bending moment while the rest three beams were tested under combined moments. Cracking load, ultimate load, deflection and twisting angle were measured during tests as well as angle and width of cracks at failure.The experimental results revealed the similarity in structural behavior between voided and solid tested specimens is clear even when the values are different. For the section strength, when the beam containing voids, it may be lost about (13 – 23) % of its solid ultimate strength under combined load of equal fractions of bending and torsion moments. Also, the cracking load of the beam may be unaffected by voids presence under this combined load. When deformability is focused, the voided beams stiffness against bending moment is better than the torsional one; therefore, the twisting angle can be more noticeable than the deflection. Besides, the torsional moment governs over the bending moment, so that inclined cracks caused in failure. Finally, creating the voids by small size plastic pipe can make the beam stronger but more deformable than counter beam containing big size plastic balls under the combined moments. Keywords: Structural behavior, Combined moments, Concrete amount, Voids presence, Spherical voids, Tubular voi

Ag–Cu Nanoalloy Electrocatalysts for Oxygen Reduction in Alkaline Media for Advanced Energy Conversion and Storage

Silver-based nanoalloys owing to their cost, performance and stability are an attractive electrocatalyst system for oxygen reduction reaction (ORR) in the alkaline fuel cells and metal air batteries. A systematic computational and experimental approach has been adopted to investigate their performance for ORR in alkaline environment. Firstly, genetic algorithm (GA) based calculations have been performed to look for the stable compositions and structures of these nanoalloys. Later, density functional theory (DFT) is employed to simulate the working of those stable nanoalloys in actual working conditions. Finally, the most promising nanoalloys have been synthesized by physical and chemical routes to confirm their performance in real-life conditions. It has been found that the alloying of silver with copper enhances the catalytic performance of Ag nanoparticles. The enhancement in performance can be related to the modification of the electronic and physical structure of Ag due to copper doping. The superior performance of Ag–Cu nanocatalysts in alkaline fuel cells and metal air batteries along with their modest cost and long-term stability make them a promising candidate for deployment as a catalyst for ORR in alkaline media

Pt-free silver nanoalloy electrocatalysts for oxygen reduction reaction in alkaline media

Silver nanoalloy electrocatalysts with comparable activity and better stability than commercial Pt/C for oxygen reduction reaction (ORR) in advanced metal–air batteries and fuel cells.</p

A silver-copper metallic glass electrocatalyst with high activity and stability comparable to Pt/C for zinc-air batteries

A silver–copper metallic glass (AgCu-MG) electrocatalyst has been fabricated for rechargeable zinc–air batteries by pulsed laser deposition. The AgCu-MG exceptionally enhances the ORR catalytic activity to a half-wave potential of 0.78 V vs. RHE after 1000 CV treatments in 0.1 M KOH.</p

Bimetallic Mn–Co Oxide Nanoparticles Anchored on Carbon Nanofibers Wrapped in Nitrogen-Doped Carbon for Application in Zn–Air Batteries and Supercapacitors

The exploration and rational design of cost-effective, highly active, and durable catalysts for oxygen electrochemical reaction is crucial to actualize the prospective technologies such as metal–air batteries and fuel cells. Herein manganese cobalt oxide nanoparticles anchored on carbon nanofibers and wrapped in a nitrogen-doped carbon shell (MCO/CNFs@NC) is successfully prepared. Benefiting from the synergistic effect between the core nanoparticles and nitrogen-doped carbon shell, MCO/CNFs@NC catalyst exhibits oxygen reduction reaction (ORR) activity with comparable onset potential (1.00 V vs RHE) and half-wave potential (0.76 V vs RHE) which is only about 40 mV lower than that of the state of art Pt/C catalyst. Furthermore, the MCO/CNFs@NC catalyst exceeds the Pt/C catalyst by a great margin in terms of stability in alkaline media. Additionally, MCO/CNFs@NC catalyst is strongly tolerant to methanol crossover, promising its applicability as cathode catalyst in alcohol fuel cells. Moreover, MCO/CNFs@NC catalyst exhibits the oxygen evolution reaction (OER) activity with low overpotential of 0.41 V at the current density of 10 mA cm^–2 and ORR/OER potential gap (Δ<i>E</i>) as low as 0.88 V, suggesting its strong bifunctionality. The Zn–air battery based on MCO/CNFs@NC catalyst is found to deliver a specific capacity of 695 mA h g^–1_Zn and an energy density of 778 W h kg^–1_Zn at a current density of 20 mA cm^–2. The mechanically rechargeable Zn–air battery based on MCO/CNFs@NC catalyst is also found to function continually by only reloading the consumed Zn anode and electrolyte. Furthermore, the electrically rechargeable battery based on MCO/CNFs@NC catalyst is found to function for more than 220 cycles with negligible loss of voltaic efficiency. Moreover, MCO/CNFs@NC is found to display a supercapacitive nature with a good discharge capacity of 478 F g^–1 at a discharge current density of 1 A g^–1

Medicinal plants from the Himalayan region as potential novel antimicrobial and anti-inflammatory skin treatments

Background and Objectives Adequate treatment of wounds remains one of the major medical needs globally, most notably in the regions with poor or limited access to health care. In many local and traditional systems of medicine, plants are often widely used for treating infected wounds. Aim and objectives The overarching aim of this project was selection of potential species for use in a future treatment by combining with plant resources with aspects of antimicrobial photodynamic therapy (aPDT). Specifically, we focussed on species used locally in the Himalayan region for the treatment of skin disorders and then assessed the existing pharmacological evidence for key species based on the published evidence available. Methods Database searches were performed to identify relevant publications describing local and traditional uses of plants in the Himalayan region of Bhutan, PR China, India, Nepal and Pakistan. Using the Global Biodiversity Information Facility (GBIF), species were researched in terms of their distribution including in different climatic regions, focussing on species mostly found in higher climatic zones (based on the Köppen–Geiger climate classification). For species used in three or more countries and restricted to the higher altitudes, data on safety, pharmacology, as it relates to dermatological conditions, and phytochemistry were retrieved. Key findings The study identified a total of 606 species that are used in the treatment of various skin conditions often associated with infections reported in 84 articles. Common weeds like Ageratum conyzoides and Bidens pilosa, widely used and cultivated species like Centealla asiatiaca and Prunus armenica were excluded. This ultimately led to the identification of a core group of five widely used species restricted to the Himalayan region (Cedrus deodara, Nardostachys jatamansi, Pinus wallichiana, Pinus roxburghii and Valeriana jatamansi). Conclusions Here we apply a novel approach comprising an assessment of the published information on the use of medicinal plants (i.e. local and traditional knowledge) in the context of their potential to be used in a biomedical form of clinical treatment – aPDT. Then, once sustainable sourcing based on access and benefit-sharing arrangements is in place, these species are investigated for their potential in wound treatment. Ultimately, the goal is to develop a new baseline for primary health care in some of the regions of the world with poor or limited access to health care