Synthesis of Antibacterial Coating Using Chitosan, Polyethylene Glycol and Silver Nanoparticles and Investigation of Their Antibacterial Properties

Chitosan/ Polyethylene glycol and silver nanoparticles based antibacterial coating has been synthesized and applied to cotton cloth using sonochemical technique. In addition to the synthesis of nanoparticles using Pyrus seed extract (Green synthesis), Chitosan and PEG compound has also been used to develop the coating in this research. The coating obtained with this compound possesses good antibacterial properties and results. The study shows that the coated fabrics and silver nanoparticles show highly potent antibacterial activity towards gram negative and gram-positive bacteria. A comparison of coating with single and multiple components is studied; specifically, a comparison of pure chitosan and polyethylene glycol coating with their blend is studied. Agar plate test is performed against pseudomonas aeruginosa, Acinetobacter baumannii and methicillin-resistant staphylococcus aureus (MRSA), and the proposed process is helpful in healthcare industry and specified applications.

Electrokinetic Desalination of Compound Building Materials by Applying Electric Field

Damaging of building materials is directly connected to the salt crystallization. The present research is based on removal of NaCl from compound building materials, where a direct current (DC) electric field was applied to the mortar plus bricks system. The main objective of this work is to investigate the electrokinetic desalination methodology that can provide sufficient removal of salts. pH neutralization in the surrounding of mortar plus bricks system is crucial to obtain sufficient desalination. For this purpose, the electrodes across the brick were inserted in kaolin clay mixed with buffer agents to suppress the pH changes. Most of the experiments were performed with kaolin clay and sponge. The concentration of chloride ions and sodium ions in all the segments and clay poultice was measured using argentometric titration method and flame photometer, whereas the pH variations in the entire system was measured by using pH indicator papers. The electrokinetic desalination was found to be an efficient method as 86 % removal of chloride and 80 % removal of sodium was achieved.

The Impact of Coal and Biomass Co-Firing on the Economy of Power Plant Carbon Capture

A detailed economic evaluation was carried out to determine the impact of biomass and coal co-firing on power plant carbon capture by methods of plants equipment designing factors and performance, and the sum up of the associated breakdowns of CAPEX and OPEX. Based on the assumptions of the CO2 neutrality of biomass and likely governmental incentives to reduce CO2 emissions, the study results show that biomass and coal co-firing would result in both lower cost of carbon avoided (carbon capture) and lower incremental cost of electricity generation when MEA solvent carbon capture is applied. Two scenarios for co-firing with carbon capture, 30% biomass blending and 90% or 60% CO2 capture from stack, indicate different preference depending on lower or higher incentives.

Bulk Utilization of Red Mud in Geopolymer Based Products

Red Mud is the solid residue generated from Alumina refinery during the process of bauxite ore processing through Bayer’s process. Typical generation of red mud is 1.5 tons of red mud per ton of alumina produced. The disposal and storage of red mud has been a concern for the alumina industry since its inception, more than a hundred years ago. With the increase in alumina production, the magnitude of the problem is getting multiplied. Its alkaline nature (Na2O ~ 3-7%) and fine size make red mud unsuitable for many applications; a limited utilization is reported in cement industries as one of the raw mix components for cement. The present work deals with the utilization of red mud in geopolymer based paving blocks. Alumina, silica and alkali are the essential items required for geopolymer preparation. Having all these in red mud, the current study attempted to use the same in geopolymer based products. The focus has been on bulk utilization of red mud; target strength of 20 MPa after 28 days of curing (M20 grade) has been the goal as this strength is sufficient for many applications. The study focused on optimizing the red mud content, alkali concentration, fly ash content, etc. The samples are tested for its compressive strength and leachability. The study reveals that significant amount of red mud incorporation is possible with products conforming to USEPA 1311 norms.

Thermodynamic Analysis of Moisture Adsorption of Taraxacum Officinale’ Powder

This work aims to model the adsorption isotherms and study the essential thermodynamic properties of Taraxacum Officinale’ powder during the moisture adsorption phenomenon at three temperatures 30, 40, and 50°C. The results have been determined by the application of the thermodynamics physical principles to the equilibrium data, which are experimentally measured. The estimated values of the isokinetic and harmonic temperatures and the Gibbs free energy change revealed that the sorption process is non-spontaneous and enthalpy driven.

Study on Negative Poisson Ratio and Energy Absorption Characteristics of Embedded Arrow Honeycomb Structure

Impact collision exists widely in people's daily life and threatens people's life safety. Negative Poisson's ratio structure has good mechanical properties. Therefore, it is of great significance to design and study the energy absorption structure with negative Poisson's ratio effect. Based on the traditional symmetrical concave honeycomb structure (SCHS) with negative Poisson's ratio, two modified negative Poisson's ratio honeycomb structures are proposed by adding embedded straight rib arrow structure and embedded curved rib arrow structure, which are respectively called embedded straight rib arrow honeycomb structure (SRAH) and embedded curved rib arrow honeycomb structure (CRAH). Through finite element simulation experiment, the negative Poisson's ratio characteristics of two cellular cells were studied and the influence of structural parameters of the cells on the Poisson's ratio was discussed. ANSYS/LS-DYNA was used to analyze the energy absorption of the proposed three cellular structures at different impact velocities. Numerical simulation results show that the SRHS and CRAH have greater stress platform value, specific energy absorption and impact force efficiency than SCHS, indicating that the SRAH and CRAH exhibited better energy absorption efficiency and impact resistance performance.

Date-Palm Fiber as a Reinforcement Filler in Polymer Composites

Natural fibers offer a great advantage of being used as a reinforcement in polymer matrix composites because of the many advantages natural fibers offer over conventional reinforcement fillers. Date palm fiber is one of the most available natural fibrous materials in the Middle Eastern region to be exploited as a fiber reinforcement in polymers. In the present work, the fibers extracted from the date palm tree trunk, branches, and leaves were used for the reinforcement of the polypropylene matrix. Electron microscopic images show excellent bonding between the fiber and matrix as no fiber pullout is observed. The thermal (heat deflection temperature) and mechanical properties (Izod impact, tensile and flexural modulus) of the composites increased with an increase in the fiber loading from 20% to 60%, which in turn resulted in excellent mechanical properties in the final product. The work has immense significance in using date palm as an easily available natural resource for a useful product.

Verifying Moisture Damage Impact in Asphalt Concrete with the Aid of Nondestructive Test NDT

One of the major concerns of pavement durability is its susceptibility to moisture damage. In this investigation, non-destructive test NDT has been implemented to detect the moisture damage issue. Asphalt concrete specimens were prepared using the traditional Marshall method for wearing, binder and asphalt stabilized base course. Specimens were traversed by ultrasound pulse velocity before and after practicing the moisture damage procedure. The variation of dynamic and elastic modulus before and after the moisture damage was considered and related to tensile strength ratio TSR. It was noted that the pulse velocity decline by (11, 11.2 and 16.4) % and the dynamic modulus declines by (28, 6.6 and 28.5) % for asphalt concrete wearing, binder and base courses respectively after moisture damage. The elastic modulus exhibits no significant variation after moisture damage for wearing course while it declines by (9 and 11.7) % for binder and base courses respectively after moisture damage. It was concluded that the elastic and dynamic moduli were unable to clearly distinguish the impact of moisture damage, whereas the Seismic modulus calculated from the Ultrasonic Pulse Velocity test was effective in distinguishing such impact. The linear equation obtained with good coefficient of determination can explain 74 % of the variation in the seismic modulus after moisture damage.

Dibenzoylhydrazines as Insect Growth Modulators: Topology-Based QSAR Modelling

Dibenzoylhydrazines Xa-(C6H5)a-CO-N-(t-Bu)-NH-CO-(C6H5)b-Yb are efficient insect growth regulators with high activity and selectivity toward lepidopteran and coleopteran pests. For 123 congeneric molecules, a quantitative structure activity relationship model was built in the framework of the QSARINS package using 2D, Topology-based, PaDEL descriptors. Variable selection by GA-MLR allows building an efficient multilinear regression linking pEC50 values to nine structural variables. Robustness and quality of the model were carefully examined at various levels: data-fitting (recall), leave-one (or some) - out, internal and external validation (including random splitting), points not in depth investigated in previous works. Various Machine Learning approaches (Partial Least Squares Regression, Projection Pursuit Regression, Linear Support Vector Machine or Three Layer Perceptron Artificial Neural Network) confirm the validity of the analysis, giving highly consistent results of comparable quality, with only a slight advantage for the three-layer perceptron.

Studies on Beneficiation of Manganese Ore through High Intensity Magnetic Separator

Upgradation techniques like wet sieving and magnetic separation were used to evaluate the beneficiation potential of manganese ore. During wet sieving, manganese content in raw ore was upgraded from 27% to a maximum value of 38% in the concentrate with a recovery of 30%. Size classification was found to have no measurable effect on manganese grade in magnetic separation. In the unsieved ground ore, manganese content of 45% was achieved with a recovery of 23% and Mn/Fe ratio of 19% at a magnetic intensity of 8500 Gauss. At the same operating conditions, SiO2 was reduced from 56% in the raw ore to 30% in the magnetic fraction. So, wet sieving technique leads to a comparatively lower manganese grade but better recovery. Conversely, a magnetic separation technique produced higher manganese grade but relatively lower recovery. Blending of the upgraded manganese ore with high grade iron ore can be done to achieve the required Mn/Fe ratio.