Effect of Ca-substitution on the magnetic and dielectric properties of Mn-Zn ferrites

Spinel Mn-Zn ferrites with composition MnxZn0.4Ca0.6-2xFe2+xO4,where x = 0.10, 0.15, 0.20, 0.25 and 0.30 have been prepared by conventional ceramic technique sintered at 1300 °C for 4 hours. The influence of Ca-substitution on various properties of Mn-Zn ferrites have been studied in this work. Investigations were carried out by the measurements of Curie temperature, permeability, loss tangent, Q-factor, dielectric constant and AC resistivity of the samples. Curie temperature (Tc), the real part of initial permeability (µ´), loss tangent (tan ?), and AC resistivity have been found to be decreased while the Q-factor increases with the increase in Ca-content. The frequency characteristics of the dielectric constant and AC resistivity have been found to be decreased as the frequency increases. Maxwell-Wagner interfacial type of dielectric polarization was observed with the addition of Ca-content over the entire range of frequency considered

Utilization of bio-oil for cooking and lighting

Among the available alternative sources of energy in Bangladesh bio-oil is recognized to be a promising alternative energy source. Bio-oil can be extracted by pyrolysis as well as expelling or solvent extractionmethod. In these days bio-oil is merely used in vehicles and power plants after some up gradation .However, it is not used for domestic purposes like cooking and lighting due to its high density and viscosity. This paper outlines the design of a gravity stove to use high dense and viscous bio-oil for cooking purpose. For this, Pongamia pinnata (karanj) oil extracted by solvent extraction method is used as fuel fed under gravity force. Efficiency of gravity stove with high dense and viscous bio-oil (karanj) is 11.81% which of kerosene stove is 17.80% also the discharge of karanj oil through gravity stove is sufficient for continuous burning. Thus, bio-oil can be effective replacement of kerosene for domestic purposes

Solar assisted fast pyrolysis: A novel approach of renewable energy production

Biofuel produced by fast pyrolysis from biomass is a promising candidate. The heart of the system is a reactor which is directly or indirectly heated to approximately 500°C by exhaust gases from a combustor that burns pyrolysis gas and some of the by-product char. In most of the cases, external biomass heater is used as heating source of the system while internal electrical heating is recently implemented as source of reactor heating. However, this heating system causes biomass or other conventional forms of fuel consumption to produce renewable energy and contributes to environmental pollution. In order to overcome these, the feasibility of incorporating solar energy with fast pyrolysis has been investigated. The main advantages of solar reactor heating include renewable source of energy, comparatively simpler devices, and no environmental pollution. A lab scale pyrolysis setup has been examined along with 1.2 m diameter parabolic reflector concentrator that provides hot exhaust gas up to 162°C. The study shows that about 32.4% carbon dioxide (CO2) emissions and almost one-third portion of fuel cost are reduced by incorporating solar heating system. Successful implementation of this proposed solar assisted pyrolysis would open a prospective window of renewable energy

ATTRITION OF SPHERICAL ELECTRODE CARBON PARTICLES DURING BATCH FLUIDIZED COMBUSTION.

Spherical electrode carbon particles prepared from carbon rods of dry cell batteries have been used to study the attrition behaviour in a bubbling fluidized bed combustor. Experiments have been conducted in a 40 mm I. D. and 1 m high fluidized bed combustor operated at 1 m/s superficial velocity. The bed was operated with nitrogen and with two different oxygen concentrations at 850 degree C to study the effect of combustion on attrition of these particles. The experimental technique used allowed the time resolution of attrited fines generation, providing detailed curves of attrition rates as a function of time. Attrition rate constants have been evaluated. Results show an enhancement of attrition due to combustion even for spherical, homogeneous and smooth particles

Solar pyrolysis: Converting waste into asset using solar energy

This chapter focuses on the incorporation of solar energy into pyrolysis reactor heating and investigates its feasibility in replacement of conventional heating. At the beginning of the chapter, an overview of pyrolysis and the historical background of pyrolysis are discussed. Furthermore, the chapter presents the issues and challenges of conventional heating of reactor during thermal decomposition of biomass. The background of solar heating and different approaches along with its updated design concepts are presented to give attention for integrating solar-assisted heating reactor in pyrolysis. The chapter also depicts the applications and feasibility of solar-integrated pyrolysis technology. At the end, possible challenges and future development scope of solar-integrated pyrolysis technology are explained. Keywords Biomass heater,,Pyrolysis, Renewable energy, Solar heating, Solar pyrolysi

Influence of ultrasonic dual mode mixing on the morphology, molecular structure and thermo-physical properties of a SiO₂-epoxy nanocomposite adhesive

<div><p>Silica nanoparticles (~15 nm) were introduced in an epoxy adhesive using an ultrasonic dual mode mixing route at different amplitudes to tune the thermo-physical properties. Processing at higher amplitude resulted in a homogeneous distribution of less clustered nanoparticles. Glass transition temperature, thermal stability, and activation energy of nanocomposites processed at 55% of amplitude showed a significant enhancement for a very low nanoparticle content of 0.5 wt%. Incorporation of a higher nanoparticle content from 2 to 5 wt% declines the properties of the composite possibly due to increasing the number of clusters rather than the cluster size which may adversely affect the cross-linking density of the base polymer.</p></div

Feasibility analysis of implementing anaerobic digestion as a potential energy source in Bangladesh

Biogas technology is one of the prevalent alternative ways to mitigate energy crisis in Bangladesh. This approach of renewable energy is becoming popular to the rural population due to its economic viability and environmental attractiveness. The aim of this review paper is to illustrate the current status of domestic biogas plants in Bangladesh. The study also assesses the total biomass potential including livestock manure and agricultural residue available for biogas generation. The assessment shows that the total estimated amount of residues is 106.27 million tons comprises 42.49 million tons from agricultural residue, and 63.78 million tons from livestock manure and municipal solid waste (MSW) which is equivalent to 5.045 billion m3 of biogas. The economic analysis of 2.0 m3, 2.6 m3, and 3.2 m3 family size biogas plants are found to be a viable option in substitution of biomass and other commercial energy. The reliable supply of low-cost feed materials for biogas production has found to be an important factor to make the plant more feasible.</p