Volume 11, Issue 8, August 2020

Trade-off between Safety of Construction Workers and Economy in Backdrop of Covid-19

Ajaya M. Ramachandra; Rajiv Gupta

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-11
DOI: 10.5185/amlett.2020.081542

The Indian Construction industry, which contributes to 8-10% of the country's GDP, is suffering from an unprecedented crisis in the wake of the COVID-19 pandemic. The Indian Government is facing a strict trade-off between preventing and containing the spread of Coronavirus on the one hand and revitalizing the economic activities which have come to complete halt/resumed partially depending on the zone to which an area depends on the other side. Impact of the lockdown on the industry, stimulus measures announced by the Indian Government, and some other actions recommended by Industry experts' for the revival of the Construction sector are discussed in this paper. The detailed specific guidelines to be adopted by the site personnel for safely resuming the site work are presented for the benefit of Industry practitioners. Experimental study results on the stability of SARS-CoV-2 virus on surfaces of different materials are presented. Also, the potential and suitability of Construction material and technology for overcoming the current challenges posed by the pandemic is discussed. The main objective of the paper is to understand the current precarious situation of the Construction industry and the strategies to overcome it for moving forward.

Recent Applications of Magnesium Oxide (MgO) Nanoparticles in various domains

Manuel Fernandes; Kshitij RB Singh; Tanushri Sarkar; Pooja Singh; Ravindra Pratap Singh

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-10
DOI: 10.5185/amlett.2020.081543

Magnesium oxide nanoparticles have emerged as a potential candidate for meeting ends of various problems due to its unique properties such as biodegradability, non-toxicity, inhibition of biofilm growth and degradation of harmful dyes such as methyl violet and many more. Along with its easy synthesis by methods such as sol-gel technique, precipitation method, and green synthesis, it is widely applicable for toxic waste remediation, antibacterial materials, removal of industrial pollutants and also used in anti-arthritic and anti-cancer activities. Prior reviews have laid focus on singular domains whereas our review clubs three major domains i.e., clinical, agricultural and environmental that are involved in the day to day life of plants as well as animals. Besides the above information, properties, synthesis, nanotoxicity and future perspectives of magnesium oxide nanoparticles have also been elaborated in this review.

Influence of Coating Thickness on the Formability of Annealed Aluminum 2024

Irfan Mahmood Khan; Kinza Tahreem; Junaid Iqbal; Zeeshan Mehmood Khan; Fatima Anjum; Abdul Mateen

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-7
DOI: 10.5185/amlett.2020.081544

Sheet metal forming of uncoated Aluminum 2024 (Al-2024-TO) alloy was performed on conventional press with a movable punch. A set of four uncoated aluminum specimens (UCS) was formed after the application of silicone-based lubricant on the specimen surface facing punch. Variation in thickness of the specimens at different locations was one of the major concerns during forming operation which caused localized thinning and hardening of stock, resulting in a premature fracture (100 mm depth). Thin porous membranes were deposited on the specimens to enhance lubrication (by retaining the lubricant) and reduce friction between clamp and stock. Four sets of coated specimens (CS) with different film thicknesses (5 μm, 10 μm, 15 μm, and 20 μm) were anodized and formed to study the effect of coating thickness and lubricant entrapment on the formed depth. Characterization of coated specimens operation exhibited that the porous thin film with an optimum thickness of 10 μm (pore diameter of 60-68 nm) facilitated the maximum entrapment of lubricant in the pores. Enhanced lubrication for CS-2 resulted in the aggravated material flow which showed minimum hardness (60 HV), minimum thickness variation (2.82-2.90 mm), and minimum draw force (11 kN) with the maximum draw depth of 172 mm.

Nonwovens with and without Super-absorbents Surface Help Firefighters as Additional Active-Cooling to Prevent Heat-Related Deaths

Sebastian Micus; Hans-Helge Böttcher; Sibylle Schmied; Michael Haupt; Götz T. Gresser

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-6
DOI: 10.5185/amlett.2020.081545

A drawback of the Personal Protective Equipment (PPE) providing firefighters protection under extreme conditions is their insufficient dissipation of heat and sweat. As a result the body core temperature increases to dangerous levels. At the German Institutes for Textile and Fiber Research Denkendorf (DITF), intensive research is being conducted on cooling materials to protect firefighters from heat related deaths. For this purpose, an active water cooling textile, consisting of different layer constructions and absorption materials has been developed. The cooling mechanism is based on evaporation of the stored water in the absorption material. Two different constructions (an open and a closed system) with various nonwoven water absorption structures, which have been integrated into a textile layer structure, have been developed. We used superabsorbents polymer fleeces and natural viscos fleeces with different weights. In preparation the exact grammage and the absorptive capacity were measured. In addition we visualized the stream in the air-conveying layer. As main test method a special thermos-physiological measurement system has been used to measure the cooling ability of the different layer constructions. Moreover possible cooling effects can be calculated.

Enhanced Electrochemical Reduction of CO2 by Zeolitic Imidazolate Frameworks-8 Supported Silver Nanoparticles

Zhihong Zhuang; Yicheng Zhang; Liang Hu; Jianli Wang; Zhao Zhang; Weiqiang Han

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-6
DOI: 10.5185/amlett.2020.081546

Silver (Ag) is a typical catalyst for CO2 electroreduction. To improve the CO faradaic efficiency, ZIF-8 supported thiol-capped Ag nanoparticles (Ag NPs) of about 3.9 nm were facilely synthesized by reducing Ag + in ZIF-8 suspension in the presence of thiol-containing mercaptopropionic acid (MPA) molecules. MPA can induce the monodisperse Ag NPs formation, cap on the surface of Ag NPs and immobilize on ZIF-8 through coordinating with the unsaturated Zn 2+ cations. The Ag/ZIF-8 can efficiently reduce CO2 to CO with a maximum CO faradaic efficiency of 92.3% at the potential of −0.88 V (vs. RHE), higher than that of ZIF-8 and Ag/C. The performance improvement in CO2 electroreduction over Ag/ZIF-8 is probably attributed to the small-size of Ag NPs and the synergistic effect between Ag NPs and ZIF-8.

Effect of Surfactant type on the Characteristics and Bioactivity of Mesoporous Bioactive Glasses

Hediyeh Nejati Rad; Aliasghar Behnamghader; Mojgan Bagheri; Masoud Mozafari

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-7
DOI: 10.5185/amlett.2020.081547

In this study, mesoporous bioactive glass 77S was synthesized by sol-gel method using two different ionic and nonionic surfactants. Physical-chemical properties of synthesized Bioglass were studied using techniques include X-ray diffraction, scanning electron microscopy, nitrogen adsorption and Fourier transform infrared spectroscopy. The results showed that using nonionic and ionic surfactants increased specific surface area by 3 and 5 times, respectively. By determining the silicon release in three different temperatures, the activation energy values of Si-O-Si for sample with surface area of 161 and 94 m 2 /g were calculated 1/10 and 1/5 of control glass with surface area of 34 m 2 /g. The pH of sample was evaluated in solutions buffered with TRIS. pH analysis results suggested a direct relation between surface area and pH changes, the greatest increase in pH was observed in the sample with the highest surface area. Moreover, the in vitro bioactivity test was also conducted in simulated body fluid (SBF) and formation of apatite layer was evaluated by scanning electron microscopy and X-ray diffraction after a day.  

Structure Factor of Charged Microemulsion Nanodroplets Decorated with Telechelic Polymers: Experimental and Numerical Study

Rachid Ahfir; Mohammed Filali

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-9
DOI: 10.5185/amlett.2020.081548

We investigate thermodynamic and structural properties of positively charged O/W microemulsion spherical nanodroplets, suspended in salt water and decorated with telechelic polymers PEO-m and PEO-2m at low and high volume fraction F (6.98%, 26.5%) by using Small Angle Neutron Scattering (SANS). We describe and propose an effective pair potential interaction between charged colloidal particles in solution both with and without added telechelic polymers PEO-m or PEO-2m.We solve Ornstein-Zernicke (OZ) integral equation in the Hypernetted Chain (HNC) closure relation to obtain the pair correlation function g(r) and the structure factor S(q). A good agreement is found between the experimental and numerical spectra assuming the interaction potentials to be the sum of attractive and repulsive contributions in terms of decoration or bridging of the nanodroplets by the PEO polymer chains.

The Catalytic Efficiency of Au3+ metal ions and Au NPs on the Oxidation of Carbonyl Compounds by in situ Generated Na2FeO4 under Microwave Irradiation for Industrial Point of View

Anamika Srivastava; Anjali Yadav; Manish Srivastava

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-5
DOI: 10.5185/amlett.2020.081549

The catalytic activity of the Au NPs and Au 3+ metal ions used in the oxidation of carbonyl compounds by in situ generated Na2FeO4 from an industrial point of view. In the subsequent study used the chemical reduction and green method in favor of the fabrication of 30 to70nm in the size of Au NPs. Carbonyl compounds converted to aromatic and aliphatic acids by the oxidation process. Au NPs give better yield as compared to Au 3+ ion since in case of bulk metal the size is enlarged and surface area reduce but converted to nanoparticles the surface area increased so catalytic activity augmented.

Synthesis, Functionalized and Characterization of Magnetic Fe3O4 Nanoparticles Protected with MCM-41 Mesoporous

Ardeshir Shokrollahi; Salimeh Abbasi; Shaghayegh Mohammadpour Shirazi

Advanced Materials Letters, 2020, Volume 11, Issue 8, Pages 1-6
DOI: 10.5185/amlett.2020.081550

In this article the synthesis of Fe3O4@MCM-41@NH-2,6-pydc as good adsorbent with potential of many applications, by coprecipitation method, was reported. For this purpose, Fe3O4 was synthesized, then protected with MCM-41 as a shell. Afterward, Fe3O4@MCM-41 functionalized by 2,6-pyridine dicarboxylic acid (pydc) after modifying by 3-aminopropyl trimethoxysilane (APTMS). This adsorbent characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET), differential thermal analysis (DTA), thermogravimetric analyses (TGA) and derivative thermogravimetric (DTG). The vibrating sample magnetometer (VSM) has been used to investigate its magnetic properties.