Chitosan/lignosulfonate nanospheres as "green" biocide for controlling the microbiologically influenced corrosion of carbon steel

In this work, uniform cross-linked chitosan/lignosulfonate (CS/LS) nanospheres with an average diameter of 150-200 nm have been successfully used as a novel, environmentally friendly biocide for the inhibition of mixed sulfate-reducing bacteria (SRB) culture, thereby controlling microbiologically influenced corrosion (MIC) on carbon steel. It was found that 500 μg·mL-1 of the CS/LS nanospheres can be used efficiently for the inhibition of SRB-induced corrosion up to a maximum of 85% indicated by a two fold increase of charge transfer resistance (Rct) on the carbon steel coupons. The hydrophilic surface of CS/LS can readily bind to the negatively charged bacterial surfaces and thereby leads to the inactivation or damage of bacterial cells. In addition, the film formation ability of chitosan on the coupon surface may have formed a protective layer to prevent the biofilm formation by hindering the initial bacterial attachment, thus leading to the reduction of corrosion.Funding: This research was funded by Qatar National Research Fund QNRF, Qatar Foundation through the NPRP grant # NPRP8-286-2-118. The publication of this article was funded by the Qatar National Library

Aerial wetting contact angle measurement using confocal microscopy

A method is presented in which the wetting contact angle of a sessile drop is acquired aerially using confocal techniques to measure the radius and the height of a droplet deposited on a planar surface. The repeatability of this method is typically less than 0.25°, and often less than 0.1°, for droplet diameters less than 1 mm. To evaluate accuracy of this method, an instrument uncertainty budget is developed, which predicts a combined uncertainty of 0.91° for a 1 mm diameter water droplet with a contact angle of 110°. For droplets having diameters less than 1 mm and contact angles between 15° and 160°, these droplets approach spherical shape and their contact angles can be computed analytically with less than 1% error. For larger droplets, gravitational deformation needs to be considered

A new approach for an ultra-thin piezoresistive sensor based on solidified carbon ink film

Conventional flexible piezoresistive strain sensors that use conductive particles polymer composites exhibit thick structures with a low sensitivity to external tension. This paper presents a cost-effective method to fabricate ultra-thin and highly sensitive piezoresistive strain sensors. In our fabrication steps, carbon ink that is mainly composed of carbon black particles is solidified with a drying process to form a “paperlike,” flexible conductive film. Without any surface modification techniques, the carbon ink film is directly placed onto liquid-state PDMS and then bonded after the drying process. Following the rapid prototyping, different performance metrics of the fabricated sensors, including piezoresistivity, gauge factor, temperature dependency, elastic modulus, and repeatability are measured. Specifically, sensors fabricated with this method show a significantly improved gauge factor (~26) compared to similar flexible sensors fabricated by more complicated micro-fabrication methods. The proposed method of fabrication and the corresponding ultra-thin (~45 μm) sensor prototype may benefit the design and mass production of future wearable biomedical and healthcare sensors.Other Information Published in: Journal of Materials Science License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s10853-020-05309-8</p

Statistical Analysis for Water Quality Assessment: A Case Study of Al Wasit Nature Reserve

This study presents a comprehensive data analysis using univariate and multivariate statistical techniques as a tool to establish a baseline for the assessment of water quality parameters in environmental compartments. The Al Wasit Nature Reserve is a hypersaline wetland in the UAE with a spatial fluctuation in water parameters as water flows above ground as well as ponds forming in deeper areas and over the year due to the arid climate and seasonality. Water samples were collected at fifteen sites along the hypersaline wetland over three periods during the months of February to March 2021 as temperatures started to rise with the oncoming summer. Water quality parameters, including the temperature, pH, turbidity, dissolved oxygen (DO), oxidation-reduction potential (ORP), electrical conductivity (EC), chemical oxygen demand (COD), chloride, ammonia, and nitrates, were measured. The results of the data analysis were used to group the sites, which were divided into three groups with similar water quality characteristics. Correlation assessments between all studied parameters revealed significant differences in the values of eight of the evaluated parameters between the three identified clusters, with only the nitrate concentrations and dissolved oxygen parameters not being significant. It was found that one of the three clusters (cluster 1) performed better than the other two for most of the studied parameters. The results of this study demonstrate the applicability and the potential time and cost savings of the usage of data analysis tools for long-term data monitoring in the wetland and other environmental systems worldwide

A Review of Carbon Nanomaterials’ Synthesis via the Chemical Vapor Deposition (CVD) Method

Carbon nanomaterials have been extensively used in many applications owing to their unique thermal, electrical and mechanical properties. One of the prime challenges is the production of these nanomaterials on a large scale. This review paper summarizes the synthesis of various carbon nanomaterials via the chemical vapor deposition (CVD) method. These carbon nanomaterials include fullerenes, carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene, carbide-derived carbon (CDC), carbon nano-onion (CNO) and MXenes. Furthermore, current challenges in the synthesis and application of these nanomaterials are highlighted with suggested areas for future research

Critical Review on Nanofluids: Preparation, Characterization, and Applications

Heat transfer fluids are a crucial parameter that affects the size and costs of heat exchangers. However, the available coolants like water and oils have low thermal conductivities, which put many limitations to the development of heat transfer to achieve high performance cooling. The need for development of new classes of fluids which enhance the heat transfer capabilities attracted the attention of many researchers. In the last few decades, modern nanotechnology developed nanoparticles, which have unique thermal and electrical properties that could help improve heat transfer using nanofluids. A “nanofluid” is a fluid with suspended fine nanoparticles which increases the heat transfer properties compared with the original fluid. Nanofluids are considered a new generation of heat transfer fluids and are considered two-phase fluids of liquid solid mixtures. The efficiency of the fluid could be improved by enhancing its thermal properties, especially the thermal conductivity, and it is expected that the nanofluids will have a greater thermal conductivity than the base fluids. This paper reviews the preparation of metallic and nonmetallic nanofluids along with the stability of the produced nanofluids. Physical and thermal properties as well as a range of applications are also discussed in detail

Democratizing the Assessment of Thermal Robustness of Metal–Organic Frameworks

With the pressing need of having reliable materials for carbon dioxide capture, metal–organic frameworks (MOFs) have shown promising performance due to their flexible sign and tunable functionality by applying reticular chemistry principles. One of the main characteristics of practical MOFs is to design thermally robust candidates for sustainable functionality. Here, we introduce a comprehensive methodology for examining the thermal stability of MOFs by combining theoretical calculations and affordable experimental methods to fully describe their performance under thermal variations. We chose the prototypical MOF, HKUST-1, to assess the methodology by performing density functional theory and classical molecular dynamics simulations and validating with experiments such as in situ powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. HKUST-1 shows thermal robustness until a temperature of 240 °C at different atmospheric gases with a reversible breathing trend with temperature. This methodology is affordable as it uses minimal experimental testing and can be applied to any MOF materials to explore its suitability for practical applications