Effect of external heat source on temperature and moisture variation for composting of food waste

This paper investigates the outcome of having an external heat source on temperature and moisture variations in the food waste composting process. Food waste accumulation is a growing concern in many countries. Converting food waste into usable compost is a more desirable tactic than dumping to crowded landfill sites. Closed composting was applied in this work, which relies on a controlled but uninterrupted airflow during the organic material degradation process. However, undesirable odour released at low aeration rate due to low temperature and high moisture content found in the compost. Finding the ideal aeration rate with the least possible loss of moisture is needed, which was discussed in this paper. The vegetable-fruit waste used in the experiment was given an aeration rate of 0.3 L/min at a moisture setting of 60% and 70%. For 15 mins/day, the forced aeration was carried out at 3-day intervals. Results showed that 0.3 L/min with 60% and 70% moisture content attained best temperature peaks of 32.4°C and 31.6°C, respectively at day 13 for 28 days composting. A strong odour continued to exist with the compost and was mitigated by using an external additional heat source (light bulb). The light bulb also helped to provide a higher temperature for the compost of 41.5°C by day 1 for 10 days composting.

Design and development of natural convective solar dryer

Solar drying has emerged as a potential drying solution for agricultural products in many developing nations. The drying behavior of the product to be dried depends on many parameters of the dryer. A box-type natural convective solar dryer was developed to analyze the drying performance of Wood chips. Experiments revealed promising drying results with drying efficiency. The design of the dryer could further be enhanced by hybridization with an external heat source.

Microwave-assisted Carbon-carbon and Carbon-heteroatom Cross-coupling Reactions in Organic Synthesis

Conventionally, the organic reactions are accomplished by conductive heating with an external heat source like an oil bath. On the contrary, since its inception, the application of microwave irradiation is growing as a suitable alternate heating method in organic synthesis. Microwave heating considerably reduces the reaction time without promoting any side reactions. The fundamental synthetic organic chemistry majorly deals with transition-metal-catalyzed C–C and C–heteroatom bond formation reactions. It is one of the most important methods in contemporary chemistry resulting in a tremendous increment in the applications of these reactions during the last few years. This field has been acknowledged with a number of Nobel Prizes during the last decade (2001, 2005 and 2010). A considerable effort has been done on the continuous development of new ligands and catalysts as well as an increased understanding of the mechanisms for the improvement of the reaction condition. This review focuses on some of the latest developments in the area of cross-coupling reactions aided by microwave irradiation.

Effect of Ti Contents on the Microstructure and Mechanical Properties of Ni˗Al˗Ti System

In this work, a ternary system prepared by Ni-Al-Ti mixed powder was synthesized using self-propagation high-temperature synthesis (SHS) process. The weight of the reactant was varied using 3%, 10%, 20% and 30% of the Ti content. The mixtures were compressed in a steel die to form compacted pellets, and subsequently ignited using an external heat source to initiate the combustion process. The synthesized products were characterized using SEM, EDS, and XRD, whereas the mechanical property of the product was measured using a Vickers microhardness test. The identification of the formed phase indicates that Ni-Al, Ti-Al and Ti-Ni systems were formed during the reaction. An increase of Ti content from 3% to 10% improves the density of the synthesized product. Further increase of Ti content to 20% results in the generation of cracks. The addition of Ti with 30% leads to the formation of a porous product. The heat released by the SHS process due to the formation of several intermetallic phases was responsible for the formation of defect products. The highest hardness of the product was achieved in the product prepared by 20% Ti content. However, the higher Ti content than 20% results in hardness reduction. This work shows that the content of 10% of Ti produced a dense and hard product.

A Study on Non-Linear DPL Model for Describing Heat Transfer in Skin Tissue during Hyperthermia Treatment

The article studies the simulation-based mathematical modeling of bioheat transfer under the Dirichlet boundary condition. We used complex non-linear dual-phase-lag bioheat transfer (DPLBHT) for analyzing the temperature distribution in skin tissues during hyperthermia treatment of infected cells. The perfusion term, metabolic heat source, and external heat source were the three parts of the volumetric heat source that were used in the model. The non-linear DPLBHT model predicted a more accurate temperature within skin tissues. The finite element Runge–Kutta (4,5) (FERK (4,5)) method, which was based on two techniques, finite difference and Runge–Kutta (4,5), was applied for calculating the result in the case of our typical non-linear problem. The paper studies and presents the non-dimensional unit. Thermal damage of normal tissue was observed near zero during hyperthermia treatment. The effects of the non-dimensional time, non-dimensional space coordinate, location parameter, regional parameter, relaxation and thermalization time, metabolic heat source, associated metabolic heat source parameter, perfusion rate, associated perfusion heat source parameter, and external heat source coefficient on the dimensionless temperature profile were studied in detail during the hyperthermia treatment process.