Electric-field-directed assembly of biomolecular-derivatized nanoparticles into higher-order structures

Multilayered structures composed of biomolecule-derivatized nanoparticles can be fabricated by electric-field-directed self-assembly. A microelectrode-array device facilitates the rapid parallel electrophoretic transport and binding of biotin and streptavidin fluorescent nanoparticles to specific sites on the microarray. Control of the current, voltage, and activation time of each of the 400-microarray electrodes allows a combinatorial approach to optimize nanoparticle binding. Under optimal conditions, nanoparticle layers form within 15 s of microelectrode activation, and the directed assembly of more than 50 alternate layers of nanoparticles is complete within an hour. The final multilayered structures are removed from the support by a relatively simple lift-off process. The electric-field process allows the parallel patterned assembly of multilayer structures using extremely low concentrations of nanoparticles and produces minimal nonspecific binding to unactivated sites. These results are significant for the development of rapid, maskless nanofabrication and hierarchical integration of biomolecular-derivatized nanocomponents into higher-order materials and devices.     

Slip-flow heat transfer in microtubes with axial conduction and viscous dissipation – An extended Graetz problem

This study is an extension of the Graetz problem to include the rarefaction effect, viscous dissipation term and axial conduction with constant-wall-heat-flux thermal boundary condition. The energy equation is solved analytically by using general eigenfunction expansion. The temperature distribution and the local Nusselt number are determined in terms of confluent hypergeometric functions. The effects of the rarefaction, axial conduction and viscous dissipation on the local Nusselt number are discussed in terms of dimensionless parameters such as the Knudsen number, Peclet number and Brinkman number.     

A method of determining thermal parameters of granular coal particles during devolatilization

Fluidized bed combustion offers great potential for the utilization of high-sulphur coal and low-grade coal in an environmentally acceptable manner. Utilization of fluidized bed technology, especially for the combustion of low quality lignites, enables pollutant emission control as well as efficient combustion. The most important stage during the combustion of coal particles is devolatilization, in which various factors such as heat transfer from the surroundings to the particle surface, heat conduction within the particle, the chemicals involved, the kinetics and the transport of volatile compounds within the particle play significant roles. The heat transfer coefficient, thermal diffusivity, thermal conductivity, heating coefficient and lag factor are the most significant thermal parameters in this process. In this study, a 1-D transient heat transfer analysis is carried out for a granular coal particle during devolatilization in a fluidized bed. The particle is idealized as a spherical solid body. Models are developed to determine the thermal parameters of such particles, and are verified using experimental centre temperatures of a 10 mm granular coal particle subjected to devolatilization at a medium temperature of 960 K. The data are taken from the literature. The results show that the thermal parameters determined here are in good agreement with experimental findings.     

ACP-ADA: A Boosting Method with Data Augmentation for Improved Prediction of Anticancer Peptides

Cancer is the second-leading cause of death worldwide, and therapeutic peptides that target and destroy cancer cells have received a great deal of interest in recent years. Traditional wet experiments are expensive and inefficient for identifying novel anticancer peptides; therefore, the development of an effective computational approach is essential to recognize ACP candidates before experimental methods are used. In this study, we proposed an Ada-boosting algorithm with the base learner random forest called ACP-ADA, which integrates binary profile feature, amino acid index, and amino acid composition with a 210-dimensional feature space vector to represent the peptides. Training samples in the feature space were augmented to increase the sample size and further improve the performance of the model in the case of insufficient samples. Furthermore, we used five-fold cross-validation to find model parameters, and the cross-validation results showed that ACP-ADA outperforms existing methods for this feature combination with data augmentation in terms of performance metrics. Specifically, ACP-ADA recorded an average accuracy of 86.4% and a Mathew’s correlation coefficient of 74.01% for dataset ACP740 and 90.83% and 81.65% for dataset ACP240; consequently, it can be a very useful tool in drug development and biomedical research.     

Effects of Kosovo’s energy use scenarios and associated gas emissions on its climate change and sustainable development

Climate change will be the first truly global challenge for sustainability. Energy production and consumption from fossil fuels has central role in respect to climate change, but also to sustainability in general. Because climate change is regionally driven with global consequences and is a result of economic imperatives and social values, it requires a redefinition as to the balance of these outcomes globally and regionally in Kosovo. Kosovo as one of the richest countries with lignite in Europe, with 95–97% of the electric power production from lignite and with 90% of vehicles over 10 years old, represents one of the regions with the greatest ratio of CO₂ emissions per unit of GDP, as well as one of the countries with the most polluted atmosphere in Europe. The modelling is carried out regionally for Kosovo for two dynamical systems which are the main emitters of greenhouse gases (CO₂, CH₄, NO_x, etc.) and air pollutants (CO, SO₂, dust CH_x, etc.): electricity generation and transportation emissions systems, for the time period 2000–2025. Various energy scenarios of the future are shown. We demonstrate that a transition to environmentally compatible sustainable energy use in Kosovo is possible. Implementing the emission reduction policies and introducing new technologies in electrical power production and transportation in Kosovo ensure a sustainable future development in Kosovo, electric power production and transport that become increasingly environmentally compatible.     

New correlations for heat transfer coefficients during direct cooling of products

An analytical method for determining the heat transfer coefficients of food products being cooled in water and in air flows is presented. Food products are idealized as geometrical solid objects of regular shapes. New correlations between heat transfer coefficients and cooling coefficients are developed in simple forms for practical use in the refrigeration industry. These correlations are then used to determine the heat transfer coefficient for a cylindrical carrot cooled in air flow as an illustrative example. In addition, evaluating the heat transfer coefficients for several products using the available experimental cooling coefficient values from the literature, two new correlations between the heat transfer coefficient and the cooling coefficient are also obtained for water and air cooling applications. The results show that the correlations presented in this article can determine the heat transfer coefficients of food products forced-convection cooling in a simple and accurate manner.     

Effect of aluminum trihydrate as flame retardant on properties of a thermoplastic rubber nanocomposite

In this work, different concentrations, per hundred rubber (phr), of aluminum trihydrate (ATH) were added to thermoplastic rubber nanocomposite based on ethylene propylene diene monomer and linear low‐density polyethylene. The effect of the added compound on the flammability, rheological, mechanical properties, and electrical conductivity of the composite was studied. The results of the cone calorimeter showed a significantly reduction in the flammability of the composites occurred when the composite was treated with ATH. The peak heat release rate was reduced by about 66% when the composite was loaded with 180 phr of ATH. Moreover, the time to ignition prolonged up to 160%. The total smoke released decreased significantly as the concentrations of the ATH were increased. A reduction of about 69% in the total smoke released was observed when the composite was treated with 180 phr. The thermogravimetric analysis showed a reduction in the overall weight loss as the concentrations of ATH were increased. A reduction of about 50% of the original weight was observed when 180 phr of ATH was used. An appreciable decrease in tensile stress and strain with increasing ATH contents had been observed. The addition of ATH markedly reduced the conductivity of the thermoplastic rubber nanocomposite. Copyright © 2016 John Wiley & Sons, Ltd.     

A Numerical Study for the Role of Natural Convection in the Melting of a GaSb/InSb/GaSb Sandwich System

The role of natural convection in the melting of a GaSb/InSb/GaSb sandwich system was numerically investigated. The melting process was assumed unsteady, and the governing equations of the model were solved by the finite difference method using a boundary fixing technique. The solutal natural convection (caused by concentration gradients) in the melt enhances melting in the lower part of the sample, and the thermal natural convection (caused by temperature gradients) is responsible for the development of a melt-solid interface that is slightly concave toward the crystals. These results are in qualitative agreement with the experimental observations made previously by the authors.     

Unconditionally stable Crank-Nicolson wave-equation PML formulations for truncating FDTD domains

Efficient, accurate and unconditionally stable perfectly matched layer (PML) formulations are presented for truncating Finite Difference Time Domain grids. The formulations are based on incorporating the Crank-Nicolson scheme into the modified Helmholtz wave-equation derived in the PML region. Numerical example carried out in one-dimension is included to validate the proposed formulations.     

Optimized exponential operator coefficients for symplectic FDTD method

A new symplectic finite difference time domain scheme is introduced. The scheme uses fourth-order finite differencing for space and a symplectic scheme with a propagator of exponential differential operators for time. The coefficients of the exponential operators are obtained by optimizing the higher order terms of the growth factor for high Courant stability limit as well as by using the Taylor's series expansion of the exponential operator for up to the second-order term. When the Taylor's series expansion of the exponential operator is considered the new scheme is second-order in time, but the dispersion performance of the scheme is similar to the performance of the fourth-order symplectic schemes previously reported. The stability performance is shown to be better, and as the new scheme uses smaller number of exponential operators it also reduces the computational time. One other advantage of this scheme is that it is flexible in the choice of the coefficients, which allows the coefficients to be chosen according to performance requirements.