Relative life cycle economic analysis of stand-alone solar PV and fossil fuel powered systems in Bangladesh with regard to load demand and market controlling factors

In this paper, relative life cycle economic analysis (LCEA) of stand-alone solar PV modules is performed with respect to portable fossil fuel driven power sources to test their commercial prospects in remote regions of Bangladesh which do not have a direct access to grid supply. Overall life time expenditures related to the power projects are analyzed and compared with the help of net present worth (NPW) theory. The influence of market controlling factors like government subsidies, excess inflation over the general trend, and price hike are established with case study of medium-scale petrol–diesel generators (0.8–10 kW) and solar photovoltaic modules (100 Wp). It is found that the cost effectiveness of conventional or ‘green’ power driven sources depends on kW rating of generators and daily demand on customer-end in the context of a developing country like Bangladesh. The demand coverage which would determine the commercial viability of renewable and non-renewable sources is calculated considering pragmatic power rating of generators available in the local market. This study is intended to assist planning of financial matters with regard to installing small to medium scale renewable projects in remote localities of Bangladesh.     

Preparation and photocatalytic H2-production on α-Fe2O3 prepared by sol-gel

In this work, the hematite α-Fe₂O₃ was synthesized by sol-gel method and characterized by X-ray diffraction and optical properties. The XRD patterns realized at different temperatures, show that pure hematite is obtained above 500 °C. The diffuse reflectance gives respectively direct and indirect optical transitions at 2.17 and 2.04 eV, in agreement with the red color. The capacitance measurement of α-Fe₂O₃ indicates p type behavior with a conduction band (?1.14 V vs. SCE), more cathodic than the H₂ evolution (～?0.8 V vs. SCE). The oxide was successfully tested for the hydrogen production under visible irradiation (29 mW cm^?2). α-Fe₂O₃ is photo-electrochemically stable in alkaline medium by hole consumption reactions involving X^2? (= SO₃^2? and S₂O₃^2?) as hole scavengers. The best photocatalytic activity for H₂ production was obtained on α-Fe₂O₃, calcined at 500 °C, in (Na₂S₂O₃ 0.025 M, pH ～ 13), with an average evolution rate of 0.015 cm³ h^?1 (mg catalyst)^?1 and a quantum efficiency of 0.26%. The system shows a tendency toward saturation, due to the competitive reduction of end products with the water reduction and the cathodic shift of the H₂ potential.     

Modeling and forecasting natural gas demand in Bangladesh

Natural gas is the major indigenous source of energy in Bangladesh and accounts for almost one-half of all primary energy used in the country. Per capita and total energy use in Bangladesh is still very small, and it is important to understand how energy, and natural gas demand will evolve in the future. We develop a dynamic econometric model to understand the natural gas demand in Bangladesh, both in the national level, and also for a few sub-sectors. Our demand model shows large long run income elasticity – around 1.5 – for aggregate demand for natural gas. Forecasts into the future also show a larger demand in the future than predicted by various national and multilateral organizations. Even then, it is possible that our forecasts could still be at the lower end of the future energy demand. Price response was statistically not different from zero, indicating that prices are possibly too low and that there is a large suppressed demand for natural gas in the country.     

The NIP Genes in Sugar Beet: Underlying Roles in Silicon Uptake and Growth Improvement

Silicon - Silicon (Si) can stimulate plant growth and stress resistance. This study aimed at elucidating the physiological responses and molecular characterization of different NIP (nodulin 26-like...     

Synthesis of methyl boron nitride film as low-k insulating film for LSI interconnection

Low dielectric constant (k) materials for the ULSI interconnect insulator are required to meet the fast development of high-speed devices. We have investigated low-k material of boron nitride containing methyl (methyl boron nitride) by using tris-di-methyl-amino-boron (TMAB) gas. The dielectric constant (k) of the film decreases with decreasing RF plasma power and the k value of the methyl BN film can be achieved as low as 1.8 at 10 W RF plasma power.Absorption band of the film was observed at 2960 cm^? 1 due to unsymmetrical stretching mode of C–H in CH₃. It is thought that increasing C–H bond with low polarizability and reducing CN bond with high polarizability can realize a lower k value. The film has also high resistivity of more than 1 × 10⁹ Ω cm and sufficient Young modulus of more than 26 GPa for the interlayer of LSI interconnection. There is a possibility that the dielectric constant can be decreased keeping the BN structure with high strength. The methyl BN film is an extremely attractive material as low-k material of next generation devices.     

Reversible Photocontrol of Microtubule Stability by Spiropyran-Conjugated Tau-Derived Peptides

Spatiotemporal modulation of microtubules by light has become an important aspect of the biological and nanotechnological applications of microtubules. We previously developed a Tau-derived peptide as a binding unit to the inside of microtubules. Here, we conjugated the Tau-derived peptide to spiropyran, which is reversibly converted to merocyanine by light, as a reversible photocontrol system to stabilize microtubules. Among the synthesized peptides with spiropyran/merocyanine at different positions, several peptides were bound to the inside of microtubules and stabilized the structures of microtubules. The peptide with spiropyran at the N-terminus induced polymerization and stabilization of microtubules, whereas the same peptide with the merocyanine form did not exert these effects. Reversible formation of microtubules/tubulin aggregates was achieved using the peptide with spiropyran conjugated at the N-terminus and irradiation with UV and visible light. Spiropyran-conjugated Tau-derived peptides would be useful for spatiotemporal modulation of microtubule stability through reversible photocontrol of binding.     

Low-temperature synthesis of bismuth titanate by modified citrate amorphous method

Bismuth titanate is a lead-free piezoelectric ceramic with outstanding properties that strictly depend on the composition and microstructure. However, bismuth-based materials are difficult to synthesize due to bismuth volatilisation that causes secondary phases and stoichiometry deviations. In this work, we propose a low-temperature chemical route, i.e. a modified amorphous citrate method, that allows a reduction of thermal treatment temperature, when compared with solid-state or other chemical routes, to obtain single-phase bismuth titanate samples. Single-phase powders with particle size under 300 nm are produced by calcination at 700 °C, and prepared into homogeneous dense pellets (density above 95%), with only isolated pores. The pellets show two distinctive features in the electrical behaviours directly associated with their mica-like microstructure: planar oriented boundaries are responsible for oxygen conduction, while the bulk is dominated by electronic conductivity. The samples show a high dielectric constant, around 200 at room temperature, while maintaining a low loss factor. The pellets also achieved a maximum polarisation of 5.85 μC/cm² and an inverse piezoelectric coefficient of 7.4 pm/V. The dielectric and piezoelectric properties obtained are comparable or superior to the state-of-the-art.     

Study of the structure,properties, scratch resistance and deformation behaviour of graded Cr-CrN-Cr(1-x)AlxN coatings

An in-depth investigation of the structure, properties, scratch adhesion characteristics of graded Cr-CrN-Cr_(1-x)Al_xN coatings synthesized onto M42 steel substrates using closed – field unbalanced magnetron sputtering (CFUBMS) was carried out. Advanced microscopy (scanning and transmission electron microscopy), focused ion beam (FIB) imaging, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and micro–scratch tests was used to investigate the microstructure, mechanical properties and scratch performance as a function of Al content. FIB and TEM investigations revealed that the coatings exhibited a distinct structure; i.e., an adhesive Cr layer, a CrN transition layer and a graded CrAlN top layer with a face centered cubic (FCC) B1 structure. A columnar morphology was exhibited by the coatings and the dimensions of the columnar grains decreased with increasing Al content. Residual stress measurements, obtained from the XRD – sin²ψ method, revealed increasing compressive stresses with increasing Al content. Furthermore, nanoindentation tests showed an increase in mechanical properties, fracture toughness index (H/E) and plastic deformation resistance (H³/E²) as the Al content increased, accompanied by a decrease in the critical load, L_C, during scratch testing implying a decrease in scratch toughness.