DFT, molecular docking and ADME prediction of tenofovir drug as a promising therapeutic inhibitor of SARS-CoV-2 M-pro

In the present work, at first, DFT calculations were carried out to study the molecular structure of the tenofovir at B3LYP/MidiX level of theory and in the water as solvent. The HOMO/LUMO molecular orbitals, excitation energies and oscillator strengths of investigated drug were also calculated and presented. NBO analysis was performed to illustrate the intramolecular rehybridization and electron density delocalization. In the following, a molecular docking study was performed for screening of effective available tenofovir drug which may act as an efficient inhibitor for the SARS-CoV-2 M-pro. The binding energy value showed a good binding affinity between the tenofovir and SARS-CoV-2 Mpro with binding energy of-47.206 kcal/mol. Therefore, tenofovir can be used for possible application against the SARS-CoV-2 M-pro.

Evaluating the technological properties of fired clay bricks incorporated with palm kernel shell

Stepping up the extraction of valuable resources from the oil palm agro-industry was fraught with palm kernel shell (PKS) disposal challenges. One mitigating measure was to recover these materials for use in fired brick production. So PKS and clay materials were characterized for their physical, mineral and thermal properties. These characterizations revealed the high content of SiO2 and Al2O3 in the clay resources and the 95.60% organic content of PKS along with its estimated 21, 774.94 (kJ/kg) higher heating value (HHV). Indexed minerals from X-ray diffraction (XRD) studies of the clay material were kaolinite, quartz, calcite and goethite. Bricks prepared with the inclusion of up to 16 wt% PKS were fired at 900 and 1000 °C. For bricks fired at 1000 °C, bulk densities decreased from 2.07 to 1.54 g/cm3, apparent porosity increased up to 89.14%, water absorption increased from 100% in reference bricks to 203.54% with the addition of 16 wt% PKS. While compressive strengths decreases were in the range of 21.67–6.07 MPa, thermal insulation improved by 22%. Similar trends were established for bricks fired at 900 °C. The analyses showed that PKS addition was more effective in tailoring the technical properties of the bricks than changes in firing temperature. The marginal differences in technical properties of bricks fired at 1000 °C relative to the 900 °C fired brick units were understood from scanning electron microscopy (SEM) studies. Therefore, this research has provided compelling evidences for use of PKS in fired brick production. © 2023 Elsevier Ltd

Experimental study on the heating/cooling and temperature uniformity performance of the microchannel temperature control device for nucleic acid PCR amplification reaction of COVID-19

The nucleic acid detection is an effective way for the prevention and control of COVID-19. PCR amplification is an important process in the nucleic acid detection. At present, PCR amplification has the problem of low heating/cooling rates, and poor temperature uniformity. This paper proposes a microchannel temperature control device for the nucleic acid detection. Five groups of parallel serpentine channels are used to increase the cooling rate of the PCR amplification. A gradual thermal conductivity design is applied to the reaction module to increase the temperature uniformity. The experimental results show that the best temperature uniformity is obtained when the materials of the inner and outer layers of the reaction module are copper and aluminum alloys, respectively. The limit and average heating/cooling rate are 7.2, 6.12, 5.52 and 5.28 °C/s, respectively, when the input power of the thermoelectric cooler is 11.07 W/cm2, the temperature and flow rate of the cooling water are 15℃ and 700 ml/min, and the thermal conductivity of the thermal grease is 6 W/(m·K). Compared with the commercial fan-fin cooling method, the limit and average heating/cooling rates are increased by 38.02%, 80.82%, 86.49% and 208.77%, respectively, with the help of microchannel cooling method. © 2023 Elsevier Ltd

Recent advances of nanotechnology in COVID 19: A critical review and future perspective

The global anxiety and economic crisis causes the deadly pandemic coronavirus disease of 2019 (COVID 19) affect millions of people right now. Subsequently, this life threatened viral disease is caused due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, morbidity and mortality of infected patients are due to cytokines storm syndrome associated with lung injury and multiorgan failure caused by COVID 19. Thereafter, several methodological advances have been approved by WHO and US-FDA for the detection, diagnosis and control of this wide spreadable communicable disease but still facing multi-challenges to control. Herein, we majorly emphasize the current trends and future perspectives of nano-medicinal based approaches for the delivery of anti-COVID 19 therapeutic moieties. Interestingly, Nanoparticles (NPs) loaded with drug molecules or vaccines resemble morphological features of SARS-CoV-2 in their size (60–140 nm) and shape (circular or spherical) that particularly mimics the virus facilitating strong interaction between them. Indeed, the delivery of anti-COVID 19 cargos via a nanoparticle such as Lipidic nanoparticles, Polymeric nanoparticles, Metallic nanoparticles, and Multi-functionalized nanoparticles to overcome the drawbacks of conventional approaches, specifying the site-specific targeting with reduced drug loading and toxicities, exhibit their immense potential. Additionally, nano-technological based drug delivery with their peculiar characteristics of having low immunogenicity, tunable drug release, multidrug delivery, higher selectivity and specificity, higher efficacy and tolerability switch on the novel pathway for the prevention and treatment of COVID 19. © 2022 The Author(s)

Recycling Discarded Facemasks of COVID-19 Pandemic to New Novel Composite Thermal Insulation and Sound-Absorbing Materials

The COVID-19 pandemic has forced the whole world to wear single-use disposable facemasks for health protection. Studies have shown that about 129 billion facemasks are wasted each month, which will contaminate the environment and create a big problem in getting rid of them. These discarded facemasks are usually dumped in garbage bins, in landfills, or in some cases littering them on the streets, which creates a health hazard to human beings. In order to solve such environmental problems, the current study presents new novel composite materials developed by recycling discarded facemasks. These materials have great potential to be used for both thermal insulation and sound-absorbing for building walls. Experiments have been performed to make bound composite materials using the discarded facemasks as new raw materials with wood adhesive as a binder. The discarded facemasks were first heated for one and half-hour at 120 degrees C to kill any contaminants (biological or others). Five different composites are made: the first uses the complete facemasks, the second uses facemasks with iron nose clip only, the third uses facemasks with no both ear loops and iron nose clip, the fourth one contains the elastic ear loops only, and the fifth one has facemasks with elastic ear loops only. Coefficients of thermal conductivity for the five samples are obtained as 0.0472, 0.0519, 0.05423, 0.0619, 0.0509 (#5, e), and 0.04347 (#5, f) W/m K at 25 degrees C, respectively. The sound-absorbing coefficient for samples 1, 2, and 3 is above 0.5 in general and, at some frequencies, approaches 0.8. Results show that the soft samples with low binder concentration have a good sound absorbing coefficient at high frequency, while the one with high binder concentration has that at a low frequency for the same facemasks' mass. Mechanical properties of all samples are also reported by performing the three-point bending moment. Composite samples have a low moisture content (0.2%) and have high thermal stability up to 325 degrees C. These composite samples could replace the petrochemical and synthetic thermal insulation materials and, at the same time, get rid of the huge discarded waste facemasks, which is considered a huge environmental problem.

High-Performance Ionanofluids from Subzipped Carbon Nanotube Networks.

Investments in the transfer and storage of thermal energy along with renewable energy sources strengthen health and economic infrastructure. These factors intensify energy diversification and the more rapid post-COVID recovery of economies. Ionanofluids (INFs) composed of long multiwalled carbon nanotubes (MWCNTs) rich in sp2-hybridized atoms and ionic liquids (ILs) display excellent thermal conductivity enhancement with respect to the pure IL, high thermal stability, and attractive rheology. However, the influence of the morphology, physicochemistry of nanoparticles and the IL-nanostructure interactions on the mechanism of heat transfer and rheological properties of INFs remain unidentified. Here, we show that intertube nanolayer coalescence, supported by 1D geometry assembly, leads to the subzipping of MWCNT bundles and formation of thermal bridges toward 3D networks in the whole INF volume. We identified stable networks of straight and bent MWCNTs separated by a layer of ions at the junctions. We found that the interactions between the ultrasonication-induced breaking nanotubes and the cations were covalent in nature. Furthermore, we found that the ionic layer imposed by close MWCNT surfaces favored enrichment of the cis conformer of the bis(trifluoromethylsulfonyl)imide anion. Our results demonstrate how the molecular perfection of the MWCNT structure with its supramolecular arrangement affects the extraordinary thermal conductivity enhancement of INFs. Thus, we gave the realistic description of the interactions at the IL-CNT interface with its (super)structure and chemistry as well as the molecular structure of the continuous phase. We anticipate our results to be a starting point for more complex studies on the supramolecular zipping mechanism. For example, ionically functionalized MWCNTs toward polyionic systems─of projected and controlled nanolayers─could enable the design of even more efficient heat-transfer fluids and miniaturization of flexible electronics.

Surface Coating of Needle-Punched Nonwovens with Meltblown Nonwovens to Improve Acoustic Properties

Unlike the term sound insulation, which means reducing the penetration of noise into other areas, sound absorption means reducing the reflection and energy of the sound on the surface. It has become a highly noticed issue in recent years because the noise in our daily life is increasing day by day, and it causes some health and comfort disorders. In many areas, textiles have been used for acoustics control and noise absorption purposes. The purpose of this work is to determine the most effective media for sound absorption performance and its relation to thermal conductivity from needle-punched nonwoven, meltblown nonwoven and hybrid forms in different arrangements of these fabrics. To provide comparable samples, both needle-punched nonwoven and meltblown nonwoven samples were produced from 100% Polypropylene fibres. According to sound absorption tests, the hybrid-structured sample having a composition similar to the needle-punched nonwoven sample placed at the bottom of our study, while the meltblown nonwoven sample placed as a face layer outperformed the rest of the samples in terms of sound absorption and thermal conductivity. ‘Meltblown only’ samples had remarkably higher sound absorption efficiency than most of the samples, while the ‘needle-punched nonwoven only’ sample had the lowest sound absorption efficiency in all frequencies.

Hydrogen-rich gas production from disposable COVID-19 mask by steam gasification.

Globally, the demand for masks has increased due to the COVID-19 pandemic, resulting in 490,201 tons of waste masks disposed of per month. Since masks are used in places with a high risk of virus infection, waste masks retain the risk of virus contamination. In this study, a 1 kg/h lab-scale (diameter: 0.114 m, height: 1 m) bubbling fluidized bed gasifier was used for steam gasification (temperature: 800 °C, steam/carbon (S/C) ratio: 1.5) of waste masks. The use of a downstream reactor with activated carbon (AC) for tar cracking and the enhancement of hydrogen production was examined. Steam gasification with AC produces syngas with H2, CO, CH4, and CO2 content of 38.89, 6.40, 21.69, and 7.34 vol%, respectively. The lower heating value of the product gas was 29.66 MJ/Nm3 and the cold gas efficiency was 74.55 %. This study showed that steam gasification can be used for the utilization of waste masks and the production of hydrogen-rich gas for further applications.

Thermo-Energy Performance of Lightweight Steel Framed Constructions: A Case Study

The building sector continues to play an essential role in reducing worldwide energy consumption. The reduced consumption is accompanied by stricter regulation for the thermotechnical design of the building envelope. The redefined nearly Zero Energy Building levels that will come into force for each member state will pressure designers to rethink the constructive details so that mandatory levels can be reached, without increasing the construction costs over an optimum level but at the same time reducing greenhouse gas emissions. The paper aims to illustrate the main conclusions obtained in assessing the thermo-energy performance of a steel-framed building representing a holistically designed modular laboratory located in a moderate continental temperate climate, characteristic of the south-eastern part of the Pannonian Depression with some sub-Mediterranean influences. An extensive numerical simulation of the main junctions was performed. The thermal performance was established in terms of the main parameters, the adjusted thermal resistances and global thermal insulation coefficient. Further on, the energy consumption for heating was established, and the associated energy rating was in compliance with the Romanian regulations. A parametric study was done to illustrate the energy performance of the investigated case in the five representative climatic zones from Romania. An important conclusion of the research indicates that an emphasis must be placed on the thermotechnical design of Light Steel Framed solutions against increased thermal bridge areas caused by the steel’s high thermal conductivity for all building components to reach nZEB levels. Nevertheless, the results indicate an exemplary behaviour compared to classical solutions, but at the same time, the need for an iterative redesign so that all thermo-energy performance indicators are achieved.

Thermal conductivity and phonon scattering of AlGaN nanofilms by elastic theory and Boltzmann transport equation

Aluminum gallium nitride (AlGaN) plays an essential role in deep ultra-violet light emitting diodes and high electron mobility transistors etc. For example, 2 nm - 5 nm AlGaN nanofilms consist of the quantum wells in ultra-violet light emitting diodes, which have been attracting extensive attention since the rise of COVID 2019. Since most photons and heat are generated in these AlGaN nanofilms, the thermal properties of AlGaN nanofilms are strongly influenced by the heat dissipation of devices. In this paper, utilizing elastic theory and the Boltzmann transport equation, the phonon dispersion relations, density of states, specific heat capacities and thermal conductivities of 2 nm Al (delta) Ga1-delta N nanofilms with various delta are theoretically calculated at different temperatures. The thermal conductivity of nanofilm is significantly smaller than that of its bulk counterpart. In contrast with bulk AlGaN, due to the dominance of boundary scattering and alloy disorder scattering, the thermal conductivity of Al (delta) Ga1-delta N exhibits a similar dependence on Al concentration to bulk Al (delta) Ga1-delta N. Meanwhile, since the screening of Umklapp scattering, the saturation temperature of thermal conductivity is delayed from 50 to 100 K in bulks to about 300 K in nanofilms. The shrinkage of nanofilms' thermal conductivity is also slower than for bulks. We believe that our work will be helpful in controlling the self-heating effect of devices based on AlGaN nanofilms.

A Critical Review on Optimization of Cold-Formed Steel Members for Better Structural and Thermal Performances

The construction and building sectors are currently responsible globally for a significant share of the total energy consumption and energy-related carbon dioxide emissions. The use of Modern Methods of Construction can help reduce this, one example being the use of cold-formed steel (CFS) construction. CFS channel sections have inherent advantages, such as their high strength-to-weight ratio and excellent potential for recycling and reusing. CFS members can be rolled into different cross-sectional shapes and optimizing these shapes can further improve their load-bearing capacities, resulting in a more economical and efficient building solution. Conversely, the high thermal conductivity of steel can lead to thermal bridges, which can significantly reduce the building’s thermal performance and energy efficiency. Hence, it is also essential to consider the thermal energy performance of the CFS structures. This paper reviews the existing studies on the structural optimization of CFS sections and the thermal performance of such CFS structures. In total, over 160 articles were critically reviewed. The methodologies used in the existing literature for optimizing CFS members for both structural and thermal performances have been summarized and presented systematically. Research gaps from the existing body of knowledge have been identified, providing guidelines for future research.

Quantifying face mask comfort.

Face mask usage is one of the most effective ways to limit SARS-CoV-2 transmission, but a mask is only useful if user compliance is high. Through anonymous surveys (n = 679), it was shown that mask discomfort is the primary source of noncompliance in mask wearing. Further, through these surveys, three critical predicting variables that dictate mask comfort were identified: air resistance, water vapor permeability, and face temperature change. To validate these predicting variables in a physiological context, experiments (n = 9) were performed to measure the respiratory rate and change in face temperature while wearing different types of three commonly used masks. Finally, using values of these predicting variables from experiments and the literature, and surveys asking users to rate the comfort of various masks, three machine learning algorithms were trained and tested to generate overall comfort scores for those masks. Although all three models performed with an accuracy of approximately 70%, the multiple linear regression model provides a simple analytical expression to predict the comfort scores for common face masks provided the input predicting variables. As face mask usage is crucial during the COVID-19 pandemic, the goal of this quantitative framework to predict mask comfort is hoped to improve user experience and prevent discomfort-induced noncompliance.