Numerical Analysis of a Small Size Baffled Shell-and-Tube Heat Exchanger Using Different Nano-Fluids

In this study, numerical simulation was used to investigate the effect of adding different nano-particles into the fluid on the performance of a baffled shell-and-tube heat exchanger. A three-dimensional modeling approach was followed to analyze the effect of different nano-fluids, at various volume fractions, as applied in a baffled shell-and-tube heat exchanger. Once finished with validating the grid independency and results, we proceeded to obtain heat transfer rate, pressure drop, outlet shell temperature and exchanger effectiveness for different volume fractions and particle size of different nano-fluids. The studied nano-particles in the present work included Al₂O₃, CuO, Fe₂O₃, Cu, Fe, SiO₂, and Au, with water and ethylene glycol employed as base fluids. With constant mass flow rate for all cases, the results indicated that, the addition of nano-particles had reduced the heat transfer coefficient, pressure drop and the rate of heat transfer through the shell, even though it had increased outlet shell temperature. In other words, considering a constant heat transfer rate, the presence of nano-fluids in a baffled shell-and-tube heat exchanger is likely to be associated with increased outlet shell temperature. Another consequence presents that using ethylene glycol as base fluid leads to higher effectiveness compared with water as a base fluid in exchanger.     

Inhibitory properties of camel whey protein hydrolysates toward liver cancer cells,dipeptidyl peptidase-IV,and inflammation

This report describes an investigation of camel whey protein hydrolysates (CWPH) produced by gastric and pancreatic enzymes for their in vitro antidiabetic, anticancer, and anti-inflammatory properties. Degree of hydrolysis (DH) ranged from 8.54 to 47.53%, with hydrolysates generated using chymotrypsin for 6 h displaying the highest DH. Reverse phase-HPLC analysis showed that α-lactalbumin underwent complete degradation, with no intact α-lactalbumin detected in CWPH. The CWPH displayed enhanced antidiabetic activity compared with intact whey proteins; with pepsin- and chymotrypsin-generated CWPH displaying greater inhibition of dipeptidyl peptidase IV (DPP-IV), α-glucosidase, and α-amylase compared with trypsin-generated CWPH. The highest antiproliferative effect was observed for CWPH generated by chymotrypsin for 3 h, with only 4.5 to 6.5% viable liver cancer cells (HepG2) remaining when tested at concentrations from 400 to 1,000 µg/mL. The highest anti-inflammatory activity was manifested by CWPH generated by pepsin at 6-h hydrolysis. We report enhanced antiproliferative, antidiabetic, and anti-inflammatory activities upon hydrolysis of camel whey proteins, indicating their potential utilization as bioactive and functional ingredients.     

Analytical calculation for input impedance of a circularly‐polarized ferrite disk antenna including higher order modes

We propose an accurate analytical model for a circularly polarized antenna comprising a normally magnetized, grounded ferrite disk with a metalized top surface. The antenna is assumed to be excited by a conventional current probe. In the case of a thin ferrite disk, the electromagnetic fields of the dominant mode of the antenna do not vary in the direction normal to the disk. However, with increasing thickness of the ferrite disk, higher order modes start to affect antenna characteristics such as resonance frequency. This work presents an analysis of the structure that takes into account all higher modes of the antenna. To validate the theoretical calculations, HFSS simulations are performed. The antenna can be tuned by changing the magnetic bias field.     

Ethyl cellulose/hydroxypropyl methyl cellulose-based oleogel shortening: Effect on batter rheology and physical properties of sponge cake

This study attempts to fill the gap in ongoing research on the design, optimization, and characterization of ethyl cellulose/hydroxypropyl methyl cellulose-based (EC/HPMC-based) low-saturated oleogel-shortenings by examining their functional effects on physicochemical, and rheological properties in the cupcake and its batter. Thus, the commercial shortening was completely replaced with the oleogel-shortenings in the cake formulation and, then, characteristics of the batter (including specific gravity, emulsion stability, and rheological properties), and cake samples (specific volume, moisture content, and texture properties) were evaluated and compared with each other and the control samples (containing commercial-shortening). In short, the EC-based- and EC/HPMC-based-oleogel-shortenings-batters had more specific gravity and emulsion stability than the control-batter. Liner viscoelastic rang in EC/HPMC-based-oleogel-shortenings-batter, EC-based-oleogel-shortenings-batter, and control-batter was 0.212%, 0.159%, and 0.195%, respectively. EC/HPMC-based-oleogel-shortenings-batter had a more viscoelastic behavior than EC-based-oleogel-shortening-batter after the control-batter (p < 0.05). The results of frequency sweep and dynamic shear tests indicated a higher similarity of the rheological behavior of the EC/HPMC-based-oleogel-shortening-batter with the control-batter. The results of moisture content and texture profile analysis of the cake samples indicated a slower staling in the oleogel-shortenings containing samples, especially EC/HPMC-based-oleogel-shortening type.     

1,4-Diazabicyclo [2.2.2] Octane Functionalized Mesoporous Silica SBA-15 (SBA-15@DABCO): a Novel Highly Selective Adsorbent for Selective Separation/Preconcentration of Cr(VI) from Environmental Water Samples

Silicon - In this research, the potential application of 1,4-Diazabicyclo[2.2.2]octane (DABCO) functionalized mesoporous SBA-15 (SBA-15@DABCO) was evaluated as a new and efficient adsorbent for the...     

Green Synthesis of Chitosan-Coated Silver Nanoparticle,Characterization, Antimicrobial Activities,and Cytotoxicity Analysis in Cancerous and Normal Cell Lines

Journal of Inorganic and Organometallic Polymers and Materials - The production of silver nanoparticles (AgNPs) using chemical synthesis routes require hazardous and toxic solvents. Nowadays, there...     

Robotic date fruit harvesting using machine vision and a 5-DOF manipulator

Date fruits can be found at the highest point of the palm tree, so harvesting can be a dangerous task for humans. In this study, a robotic arm is presented to harvest date fruits. A manipulator, traveling on a U-shaped rail with four prismatic joints and one revolute joint, was designed and constructed to approach the fruits efficiently. The end-effector of the manipulator was an electric chainsaw capable of cutting the date bunch. Two cameras were located on the manipulator in perpendicular directions to capture images, which were then transmitted to a decision-making unit to control the speed of the manipulator links. The decision-making unit included three fuzzy inference systems that used the location data of the fruit bunch stems and the area of tree leaves in the images to determine the speed of electromotors of the trolley, horizontal link, and vertical link. An artificial palm tree with dimensions similar to a real palm tree was constructed to evaluate the performance of the robot. The performance of the robot was evaluated in various lighting conditions. The results showed that the introduced image processing algorithm could adequately detect the stems of the date bunches with accuracy, precision, and recall of 0.88, 0.92, and 0.96, respectively, in suitable lighting, that is, when there was sufficient natural lighting. Moreover, the experimental results revealed that the accuracy of the control system in cutting the stems was 87%, with a production loss of 5%. The proposed robot makes it possible to improve the capacity of using mechanized harvesting in date palm fields.     

Deposition Patterns of Evaporating Sodium Alginate Sessile Droplets Cross-Linked by Calcium Chloride

Controllable patterning of bio-compatible polymers in the presence of a cross-linker in evaporating bi-dispersed colloidal drops is of critical importance in functional coatings, bioprinting, and food packaging. This study investigates the effect of calcium chloride and sodium alginate concentration on the evaporative deposition and elemental distribution of dried-out patterns. Different concentrations of alginate and salt in aqueous solutions are deposited on clean glass substrates to gain a deeper understanding of the final structures. Overall, the results indicate that changing the concentrations of sodium alginate and calcium chloride can significantly alter the elemental distribution and deposition uniformity of the final patterns. The modifications in relative concentration alter the physicochemical characteristics of the solution, resulting in significant changes in the pinning time and contact angle of the droplets that correspond to the alteration of the colloidal size and concentration, ultimately resulting in significant differences in deposition patterns. The dried-out patterns are categorized based on their structures and mechanisms (crystallization, sedimentation, and adsorption) controlling the evaporative deposition, and then justified based on the competitive effects of cross-linking, crystallization, and evaporation-driven flows. Using scanning electron microscopy and energy-dispersive X-ray spectroscopy, the elemental distribution of dried-out patterns is also mapped to substantiate the discussion made.     

Adapting Shot Peening for Surface Texturing Using Customized Additive Manufactured Shots

Surface textures in engineering materials not only affect the reflective properties and aesthetics but if properly designed can modulate surface-related properties such as wettability, fatigue, wear, corrosion, and scratch resistance. Herein, a new surface texturing method is introduced based on the conventional shot peening process. Custom shots are designed, and their surface texturing capability is investigated on acrylonitrile butadiene styrene (ABS) polymer substrates. A finite-element model is developed to bombard the substrate using AISI 316 stainless steel customized shots. The generated unique textures are compared qualitatively by visual examination and quantitatively using the standard surface roughness parameters. As a proof of concept, preliminary experiments are performed using a candidate custom shot and a spherical shot to treat the ABS sheets. The results highlight the high potential of the shot peening technique paired with additive manufacturing for customizing the peening media to be used for surface texturing polymeric materials.