In situ interface engineering for probing the limit of quantum dot photovoltaic devices.

Quantum dot (QD) photovoltaic devices are attractive for their low-cost synthesis, tunable band gap and potentially high power conversion efficiency (PCE). However, the experimentally achieved efficiency to date remains far from ideal. Here, we report an in-situ fabrication and investigation of single TiO2-nanowire/CdSe-QD heterojunction solar cell (QDHSC) using a custom-designed photoelectric transmission electron microscope (TEM) holder. A mobile counter electrode is used to precisely tune the interface area for in situ photoelectrical measurements, which reveals a strong interface area dependent PCE. Theoretical simulations show that the simplified single nanowire solar cell structure can minimize the interface area and associated charge scattering to enable an efficient charge collection. Additionally, the optical antenna effect of nanowire-based QDHSCs can further enhance the absorption and boost the PCE. This study establishes a robust 'nanolab' platform in a TEM for in situ photoelectrical studies and provides valuable insight into the interfacial effects in nanoscale solar cells

Effect of dietary supplementation of cassia auriculata leaf powder on growth and immune responses of milkfish, Chanos chanos

A 30 days feeding trial was conducted to evaluate the effects of Cassia auriculata leaf powder on growth and immunomological parameters of the juveniles of Milkfish, Chanos chanos and disease resistance against Vibrio anguillarum. The juvenile fishes with an average weight of 20±3 g were stocked in four treatments each with three replicates. Four practical diets were prepared with graded level of Cassia auriculata leaf powder (CAL) at the rate of 0%, 0.5%, 1% and 1.5% and fed to four treatments respectively named as CAL0, CAL0.5, CAL1 and CAL1.5. At the end of the experiment blood samples were collected for immunological parameters. After sampling, the remaining fishes were challenged with 0.1 mL of virulent V. anguillarum suspension at a concentration of 107 CFU mL-1 and mortality was observed for 7 days. Post challenge sampling was performed for the collection of blood samples. The growth parameters such as Weight gain%, SGR%, PER were positively affected by Cassia auriculata leaf powder incorporated diet. Higher weight gain %, SGR% and PER were noticed in CAL1.5 group followed by CAL1, CAL0.5 and CAL0. The respiratory burst, lysozyme and phagocytic activities were increased with increasing level of CAL in the diet which indicates better immune response of the fishes fed with CAL. The higher respiratory burst (0.522 ± 0.03), lysozyme (70.07 ± 1.57) and phagocytic (52.91 ± 1.76) activitieswere observed in CAL1.5, CAL1 and CAL1.5 groups respectively during pre-challenge and post challenge. There was significant difference in the survival rate of control (CAL0) and CAL incorporated diet fed groups (P<0.05). Maximum survival was witnessed in CAL1 followed by CAL1.5 and least survival was in CAL0 group. The results indicate that diets supplemented with 1% CAL potentially enhance the immune system and effectively protects the host against V. anguillarum infection and thereby improve the survivability of the fish against this dreadful pathogen

Life cycle assessment of biochar production from southern pine

Biochar, a major co-product from the pyrolysis of lignocellulosic biomass is rich in carbon and is often used as a soil amendment to promote crop production and as a soil carbon sequestration medium to maintain long-term soil health of marginal lands. Pyrolysis is the thermal decomposition of biomass in the absence of oxygen to primarily produce bio-oil with biochar being a co-product. Biochar is also primarily produced from wood logs using conventional carbonization methods (eg. Missouri kilns). For sustainable production of biochar, the most sustainable production route is important for large-scale production of biochar for soil carbon sequestration applications. The main objectives of this study were to conduct the life cycle analysis of producing biochar using three major production routes (fast pyrolysis, slow pyrolysis and Missouri kiln) and to evaluate the life cycle energy and environmental impacts of biochar production from southern pinewood. Please click on the file below for full content of the abstract

Microplastic emerging pollutants – impact on microbiological diversity, diarrhea, antibiotic resistance, and bioremediation

Advanced economic development and technologies cause worldwide plastic waste to increase many folds, leaving policymakers with the dilemma of managing it. Synthetic solid particles or polymeric matrices of plastics with diverse shapes and sizes are the primary concern of environmental pollution of the marine ecosystem, freshwater, agriculture fields, atmosphere, food, drinking water, and other remote locations. Researchers demonstrated microplastics (MPs) as multifaceted stressors in the ecosystem, carrying toxic chemicals and vectors of transport, and described the implications of these hazardous chemicals on human health. MPs in the environment can adsorb organic, nitrogenous substances and other minerals. This complex system may promote microbial growth and aggregation. Continuous contact of microbes with MPs changes the internal arrangement of ions and atoms, alternating physio-chemical properties and becoming hydrophobic. These properties allow specific bacterial growth on MPs and promote bacterial resistance and transfer of resistance genes. MPs aged by ultra-violet light, temperature, and chemicals increase bacterial adsorption and antibiotic-resistance gene transfer synergistically. MPs are mitigated in the environment by aggregation of microbes, which leads to aging and loss of the crystalline structure of microplastic due to the release of enzymes that cause oxidation, demethylation and desertification, and hydrolysis of MPs. Aerobic conditions are preferred to degrade MPs in different environmental conditions for large-scale degradation of MPs. However, anaerobic degradation requires controlled conditions and specialized equipment. The use of a consortium of bacteria increases biodegradation efficiency. Among the microorganisms, fungi were the most effective at detoxicating xenobiotics in the environment due to their adaptability and ability to tolerate diverse conditions. This critical review analyses microplastic-induced microbial diversity and microbial adaptations to it. Furthermore, it describes MP's role in the cause of diarrhea, antimicrobial resistance, and spread. The potential use of bioremediation methods and pathways for eliminating MPs like phthalates and bisphenol from ecosystems is discussed in detail. Finally, suggestions are put forward for controlling and removing MPs from the environment

Free Vibrational Behavior of Bi-Directional Functionally Graded Composite Panel with and Without Porosities Using 3D Finite Element Approximations

Abstract: In the present study, the frequency characteristics of bi-directional functionally graded panels in rectangular planform with and without porosities are examined using 3D finite element approximations. In this work, the graded panel is consisted of metal and ceramic material, in which material properties vary smoothly in two directions. The material properties of this highly heterogeneous material are obtained using the Voigt model via extended power-law distribution of volume fractions. The present model is developed using a customized computer code and discretized using three dimensional solid 20-noded quadrilateral elements. The mesh refinement is carried out to conduct the convergence test and the validation test by comparing the obtained results with the previous reported results. At a later stage, a comprehensive parametric study is conducted through numerical illustrations which reveal that the geometrical and material parameters of bi-directional functionally graded panel affect its frequency characteristics, significantly

Physical properties of charred pellets after two months of storage

Six types of charred pellets: canola straw, willow, bagasse, wheat straw, switchgrass and miscanthus, were stored for a period of two months at room temperature 25±2 °C in sealed containers. The tests were part of off gassing experiment on charred and uncharred pellets. The following physical properties of the pellets were measured: bulk density, individual pellet density, Individual pellet dimensions were similar between samples but the pellet mass ranged from 0.79 g for switchgrass to 1.13 g for bagasse pellet. Please click on the file below for full content of the abstract