Modeling Intermittent Drying of Wood under Rapidly Varying Temperature and Humidity Conditions with the Lumped Reaction Engineering Approach (L-REA)

For improving product quality and minimizing energy consumption during drying, intermittent drying is often recommended. The mathematical models that are used to describe intermittent drying are usually transport phenomena based, complex models. In this study, the lumped reaction engineering approach (L-REA) is implemented to model wood drying under rapid periodically changed drying air temperature and humidity with high number of cycles of intermittency. The equilibrium activation energy (ΔE _v,b ), an important parameter for REA approach, is evaluated according to the corresponding drying air temperature and humidity in each drying section. The results of modeling suggest the L-REA works well with the experimental data. The simplicity of the L-REA is obvious and is hoped to be used in an industrial setting more readily. The L-REA can be used for sustainable processing in industries to assist in energy audit and management.     

Fed batch enzymatic saccharification of newspaper cellulosics improves the sugar content in the hydrolysates and eventually the ethanol fermentation by Saccharomyces cerevisiae

The newspaper is comprised of (w w^?1) holocellulose (70.0%) with substantial amount of lignin (16.0%). Bioconversion of the carbohydrate component of newspaper to sugars by enzymatic saccharification, and its fermentation to ethanol was investigated. Of various enzymatic treatments using cellulase, xylanase and laccase, cellulase enzyme system was found to deink the newspaper most efficiently. The saccharification of deinked paper pulp using enzyme cocktail containing exoglucanase (20 U g^?1), β-glucosidase (60 U g^?1) and xylanase (80 U g^?1) resulted in 59.8% saccharification. Among additives, 1% (v v^?1) Tween 80 and 10 mol m^?3 CoCl₂ improved the enzymatic hydrolysis of newspaper maximally, releasing 14.64 g L^?1 sugars. The fed batch enzymatic saccharification of the newspaper increased the sugar concentration in hydrolysate from 14.64 g L^?1 to 38.21 g L^?1. Moreover, the batch and fed batch enzymatic hydrolysates when fermented with Saccharomyces cerevisiae produced 5.64 g L^?1 and 14.77 g L^?1 ethanol, respectively.     

Stress Spikes in Pin and Hanger System of Truss Bridge

Several functional problems have been reported on pin and hanger system truss bridges, such as frozen pins, stress spikes in hangers, lack of expansion joint movements, etc. It has been difficult to develop a pin and hanger retrofit strategy because the cause for the observed problems is usually unknown. This paper presents a study performed on the pin and hanger system of one such bridge—the Newburgh Beacon bridge. Extensive field testing performed so far has failed to identify the cause for the observed stress spikes. The concept of misalignment loading is developed in this article to explain the observed behavior. Stress spikes predicted using this concept matched very well with the observed stress spikes. Finally, the use of misalignment loading to evaluate other truss members is also discussed.     

Switched-capacitor filters

A novel technique for building active filters using switched-capacitor (SC) circuits is proposed. Principles of operation, methods of control, analysis, and design of a typical SC filter are presented. To assess its effectiveness, the technique is used to control input current harmonics in a phase-controlled converter. It is shown that a wide range of harmonics can be controlled using a single filter     

An Improved Pinchoff Equivalent Circuit Model for Determining PHEMT Model Parameters for Millimeterwave Application

An improved equivalent circuit model under pinchoff condition for extracting parasitic model parameters for Double Heterojunction δ-doped PHEMTs is presented. Good prediction for S parameters and noise performance are obtained up to 40GHz. A modified parameter extraction technique based on this new model was use to determine a PHEMT equivalent circuit model. Signification improvements of the accuracy of S parameters are obtained by using the new pinchoff model.     

Contouring of Diffused Objects by Using Lensless Fourier Transform Digital Holography and Dual‐Index Immersion Method

Abstract: A simple method for contouring of diffused objects by using lensless Fourier transform digital holography and dual‐index immersion method is presented. It is noticed that to get more accurate results speckle noise should be eliminated/reduced from the reconstructed phase map from digital holograms. Speckle noise is handled by 5 × 5 median filtering. Depth contour interval up to a maximum of 0.12 mm could be achieved without making the interference phase fringes overcrowded.     

Simplified method of calculating legendre coefficients for computing optical properties of colorants

The Kubelka-Munk (K-M) theory is widely used for instrumental colour measurement and colorant formulation in modern colour technology. The K-M theory is derived with certain assumptions and hence has several limitations. A more rigorous theory called the many-flux (M-F) technique was recently proposed by Mudgett and Richards to overcome the limitations of the K-M theory. Application of the M-F technique requires lengthy computations and hence is not suitable for industrial organizations for day-to-day work. It has been shown that the limitations of the K-M theory and the complexity of the M-F technique can be significantly reduced if simple equations are developed to calculate Legendre coefficients. Empirical equations to calculate Legendre coefficients (a_n/a_o, n = 1,2) are developed. The validity and utility of these equations have been confirmed by computing K-M scattering coefficients and phase functions, and comparing them with those computed using Mie-theory values. The use of these equations to determine the values of refractive index of colorants is also shown. The work reported in this article simplifies to some extent the computation of reflectance using the M-F technique and enable the estimation of K-M scattering coefficients with change in size of pigments. Utility of the proposed equations is established by computing reflectance by the M-F technique and comparing it with values obtained by using rigorous Mie equations for Legendre coefficients.     

Seismic strength of adobe masonry

The most important soil characteristies from the viewpoint of the strength of adobe masonry are first studied. Subsequently, based on the acquired knowledge, the effect of some natural additives to the soil is investigated. Simple field tests, devised to identify the most adequate materials for adobe construction and to be easily transmitted to the potential adobe builder are finally proposed.     

Application of the reaction engineering approach (REA) to model cyclic drying of thin layers of polyvinyl alcohol (PVA)/glycerol/water mixture

Rapid development of industrial polymer-based product requires considerable research in polymer drying. Cyclic or intermittent drying is used occasionally to save energy and improve product quality. Most published studies employ diffusion-based models. Reaction engineering approach (REA) is a lumped parameter model which is comparably simple and is now applied to cyclic situation for the first time. New definitions of equilibrium activation energy (ΔE_v,b) had to be introduced. With these definitions, very reasonable agreement between the predicted and published experimental data is shown. It has advantage over the diffusion model where in general complex diffusivity functions are used and had to be established using experimental data anyway. REA may be used in plant-wide simulations, where the drying kinetics has to be coupled with many other equations to be solved together. In this case, the computation time would be generally reduced if there is no need to solve the spatial distribution of water content inside the product.     

Effect of infestation (Callosobruchus Chinensis L.) of chick peas (bengal gram) on biological utilization of proteins

Bengal gram (Cicer aritinum) was infested with Callosobruchis Chinensis (L.) at 20%, 40% and 60% level of infestation and fed to rats for 40 days. Effect of incorporation of uninfested and infested bengal gram on feed intake, weight gain, protein efficiency ratio (PER), true protein digestibility (TPD), biological value (BV), net protein utilization(NPU) and changes in internal organs were studied. Inclusion of infested grains had significant effect on the utilization of proteins. Diets having 60% infested grains had lower PER, TPD, BV and NPU. With increase in level of infestation weight of liver, kidney and spleen decreased significantly.