ABSTRACT
Since December 2019, COVID-19 infection rates have risen considerably, and the virus is currently widespread around the world. Following the COVID-19 outbreak, the production of medical waste has skyrocketed. Disposable face masks are considered medical waste. Alternative measures must be implemented to assist in reducing medical waste disposal, which can result in serious public health problems and have a negative influence on the environment. In this regard, this research was conducted to investigate the effect of disposable face mask (DFM) ash with varied rates ranging from 5% to 20% by weight on bitumen with a 5% increment to be utilised as an alternative material in asphalt pavement. A series of physical and rheological tests were conducted on the bitumen samples to study the behavior of the DFM ash in bituminous material. Overall, the physical and rheological test results revealed that introducing 20% DFM ash to the modified bitumen was unable to achieve the same properties as with the conventional SMA14 asphalt binder. However, the modified bitumen penetration grade PEN 60/70 has improved the properties and quality of the asphalt in the flexible pavement. In addition, utilising the DFM waste in road construction would be a sustainable technique for protecting the environment by minimising face mask waste caused by the COVID-19 epidemic while lowering the pavement's construction cost. These research findings may be commercialised to generate revenue in the construction industry for sustainable transportation pathways.
ABSTRACT
The rapid response to the COVID-19 pandemic has resulted in increased municipal waste in the form of used face masks (FMs), which pose a global threat to the environment. To mitigate this, the study explores the applicability of shredded FMs as alternative reinforcing material in sands. Laboratory-grade Ottawa sand and naturally collected sea sand are adopted as the base sands for testing. The primary physical properties of the base materials and the FMs are first examined, and the soil particles are imaged via scanning electron microscopy. Thirty consolidated undrained (CU) triaxial compression tests were conducted to evaluate the effects of the weight fraction of FM, FM length, and the initial effective mean stress on the undrained shear strength parameters of the sands. The experimental results proved that FM inclusion can lead to a substantial improvement in the undrained shear strength of the sands;however, such improvement was sensitive to the initial effective mean stress, with higher undrained shear strength gains associated with lower initial effective mean stress. For a given FM content, the critical state ratio and angle of friction at the critical state increased with the FM length. Finally, the results revealed that FM-reinforced sands exhibit dilative and strain-hardening behaviors.
ABSTRACT
A variety of graphical invariants have been described and tested, offering lots of applications in the fields of nanochemistry, computational networks and in different scientific research areas. One commonly studied group of invariants is the topological index, which allows to research the chemical, biological, and physical properties of a chemical structure. Topological indexes are numerical quantities that can be used to describe the properties of the molecular graph. In this article, we draw from the analytically closed formulas of certain molecular structures of coronavirus such as Ribavirin, Sofosbuvir and Oseltamivir by calculating temperature based topological indices.
ABSTRACT
To understand the complex phenomena in social space and monitor the dynamic changes in people's tracks, we need more cross-scale data. However, when we retrieve data, we often ignore the impact of multi-scale, resulting in incomplete results. To solve this problem, we proposed a management method of multi-granularity dimensions for spatiotemporal data. This method systematically described dimension granularity and the fuzzy caused by dimension granularity, and used multi-scale integer coding technology to organize and manage multi-granularity dimensions, and realized the integrity of the data query results according to the correlation between the different scale codes. We simulated the time and band data for the experiment. The experimental results showed that: (1) this method effectively solves the problem of incomplete query results of the intersection query method. (2) Compared with traditional string encoding, the query efficiency of multiscale integer encoding is twice as high. (3) The proportion of different dimension granularity has an impact on the query effect of multi-scale integer coding. When the proportion of fine-grained data is high, the advantage of multi-scale integer coding is greater.
ABSTRACT
Stoneware is a ceramic material with low porosity and high mechanical properties, such as the modulus of rupture. It is essentially made of clay, feldspar and quartz and is sintered to create a mixture of glass and crystalline phases. With the projected growth rate of the global ceramics market size and the country's development plan for 2023–2028, it is imperative that alternative raw materials for the manufacture of ceramic products be sourced so that the importation of these materials, such as feldspar, be minimized, if not eliminated. Cinder in the Philippines is mainly used as a filling material in pavements and residential areas. In this study, this resource is utilized as partial and full replacement of feldspar in a typical ternary diagram for stoneware production. Bars were formed from different formulations by the slip casting method and were sintered at 1200 °C. Physical and mechanical properties of the bars, such as shrinkage, loss on ignition, water absorption, apparent porosity and modulus of rupture were determined. Thermo-physical analyses were also carried out on the raw materials and on formulated powders. Meeting the requirements of the various quality standards for ceramics, the partial replacement of feldspar with black cinder (LF, LFBQ and LFBH) is feasible for wall and roof applications while full replacement of feldspar with black cinder (LB) is suitable for wider use as wall, floor, vitrified, industrial and roof tiles.
ABSTRACT
Orange-fleshed sweet potato (OFSP) and pumpkin fruit are underutilized crops with great potential for the production of high-quality bread with health-enhancing properties. However, the incorporation of nonconventional flour in bread formula may influence the dough and bread quality properties. This study investigated the effect of partial substitution of wheat flour with OFSP (10–50%) and pumpkin flour (10–40%), baking temperature (150–200 °C) and baking time (15–25 min) on the quality properties of the composite dough and bread using response surface methodology (RSM). Dough rheological, bread physical and textural properties were analyzed, modelled and optimized using RSM. Satisfactory regression models were developed for the dough and bread quality attributes (R2 > 0.98). The dough development time, crust redness, hardness, and chewiness values increased while optimum water absorption of dough, specific volume, lightness, springiness, and resilience of bread decreased significantly (p < 0.05) with increasing incorporation of OFSP and pumpkin flour in the bread formula. Additionally, the specific volume, crust redness, crumb hardness, and chewiness of the composite bread increased significantly (p < 0.05) with increasing baking temperature from 150 to 180 °C but reduced at higher baking temperatures (≥ 190 °C). The staling rate declined with increased OFSP and pumpkin flour whereas increasing the baking temperature and time increased the bread staling rate. The optimized formula for the composite bread was 78.5% wheat flour, 11.5% OFSP flour, 10.0% pumpkin flour, and baking conditions of 160 °C for 20 min. The result of the study has potential applications in the bakery industry for the development of functional bread.
ABSTRACT
A better understanding of the fluid dynamics of disease transmission by disintegrated respiratory droplets has been the focus of great attention since the recent outbreak of COVID-19. In particular, human respiratory activities such as coughing, sneezing and even talking and eating expel a large amount of pathogen-laden droplets. Particularly, during eating or drinking, the physical properties of saliva can be changed. In this study, we investigate the atomization morphology of expelled artificial saliva mixtures from the perspective of varying fluid physical properties, specifically surface tension and dynamic viscosity. Using high-speed shadowgraph experiments on artificial saliva, we visualize and analyse the disintegration of saliva liquid sheets into ligaments and droplets. We find that the viscosity and surface tension affect the droplet size formed from expelled saliva and follow scaling laws that have been previously observed and predicted for constant shear viscosity. We conclude that the changes in physical properties of saliva induced by eating and drinking tend to favour the formation of smaller droplets during sneezing or coughing, which could drive the airborne transmission pathway of pathogens. Furthermore, we derive a theoretical model based on scaling arguments that shows the breakup time of ligaments produced from the artificial saliva mixtures is dependent on the capillary number.
ABSTRACT
Ionizable lipids with branched tails have been used in lipid nanoparticles (LNPs)-based messenger RNA (mRNA) therapeutics like COVID-19 vaccines. However, due to the limited commercial availability of branched ingredients, a systematic analysis of how the branched tails affect LNP quality has been lacking to date. Herein, a-branched tail lipids are focused, as they can be synthesized from simple commercially available chemicals, and the length of each chain can be independently controlled. Furthermore, symmetry and total carbon number can be used to describe a-branched tails, facilitating the design of a systematic lipid library to elucidate "structure-property-function" relationships. Consequently, a lipid library is developed containing 32 different types of a-branched tails. This library is used to demonstrate that branched chains increase LNP microviscosity and headgroup ionization ability in an acidic environment, which in turn enhances the stability and in vivo efficacy of mRNA-LNPs. Of the branched lipids, CL4F 8-6 LNPs carrying Cas9 mRNA and sgRNA could achieve 54% genome editing and 77% protein reduction with a single dose of 2.5 mg kg(-1). This mechanism-based data on branched lipids is expected to provide insights into rational lipid design and effective gene therapy in the future.
ABSTRACT
The COVID-19 pandemic and its related restrictions forced the reorganization of learning methodology and gave a central role to remote learning. Laboratory experiments are the most affected activity, and several alternatives were described. This work proposes to create calculation tools by simply programming in Visual Basic of Excel to emulate the data acquisition of specific laboratory experiments. The approach appears useful in experiments with a simple setup followed by data analysis. The experiment of gas volumetric properties allows fixing pressure and temperature conditions and measuring the occupied volume. The developed program emulates such operations and reports a computed volume. Further data reduction is the same in both procedures. Such a virtual experience was successfully used with groups of over 100 students. The results obtained were satisfactory compared with those obtained in the laboratory. Detailed analysis of the grades shows that acquired skills are comparable in both methodologies. Consequently, the virtual approach is a flexible option for remote laboratory teaching to complement traditional experimentation. Published 2022 by American Chemical Society and Division of Chemical Education, Inc.
ABSTRACT
Natural aggregates are being depleted due to the high demand for road and building construction and need to be replaced with alternative materials. This study investigated the potential of using Palm kernel shells (PaKS) as a partial replacement for natural aggregates (NA) and waste plastics (WP) as a binder. The physical and volumetric properties of the different asphaltic mixes (AM) were assessed using the Marshall Method. The bitumen content of the mix design samples was varied from 4.0% to 7.5% of the total weight of aggregates utilized. According to the Marshall parameters, at 5.5% bitumen content, the maximum Marshall Stability value of the different mix designs increased from 9.8 kN to 12.1 kN and the flow value increased from 3.0 mm to 3.7 mm. The experimental results based on the optimum bitumen content determined by the Marshall method demonstrate that PaKS and WP can be utilized to modify AM. However, additional tests will be needed to evaluate the use of this composition in road construction.
ABSTRACT
Ionizable lipids with branched tails have been used in lipid nanoparticles (LNPs)-based messenger RNA (mRNA) therapeutics like COVID-19 vaccines. However, due to the limited commercial availability of branched ingredients, a systematic analysis of how the branched tails affect LNP quality has been lacking to date. Herein, alpha-branched tail lipids are focused, as they can be synthesized from simple commercially available chemicals, and the length of each chain can be independently controlled. Furthermore, symmetry and total carbon number can be used to describe alpha-branched tails, facilitating the design of a systematic lipid library to elucidate "structure-property-function" relationships. Consequently, a lipid library is developed containing 32 different types of alpha-branched tails. This library is used to demonstrate that branched chains increase LNP microviscosity and headgroup ionization ability in an acidic environment, which in turn enhances the stability and in vivo efficacy of mRNA-LNPs. Of the branched lipids, CL4F 8-6 LNPs carrying Cas9 mRNA and sgRNA could achieve 54% genome editing and 77% protein reduction with a single dose of 2.5 mg kg(-1). This mechanism-based data on branched lipids is expected to provide insights into rational lipid design and effective gene therapy in the future.
ABSTRACT
Topological indices are an important method for understanding the fundamental topology of chemical structures. Quantitative structure properties relationship (QSPR) is an analytical approach for breaking down a molecule into a sequence of numerical values that describe the chemical and physical characteristics of the molecule. In this article, we have developed the QSPR analysis between eigenvalue-based topological indices and physical properties of COVID-19 drugs to predict the significance level of eigenvalue based indices. We have to use MATLAB for the computation of indices and SPSS for analysis. We show that positive interia index, signless Laplacian Estrada index and Randic energy are the best predictors of molar reactivity, polar surface area and molecular weight, respectively.
ABSTRACT
To clarify the most suitable fish paste for preparing lion's head meatballs, this study investigated the effect of adding 6 different silver carp fish pastes: fresh unwashed (group 1-1), fresh washed (group 1-2), frozen unwashed without antifreeze agent (group 2-1), frozen washed without antifreeze agent (group 2-2), frozen unwashed with antifreeze agent (group 3-1), and frozen washed with antifreeze agent (group 3-2) on the basic nutrients, color, texture properties, waterholding capacity, sensory and flavor properties, thiobarbituric acid reactive substance (TBARs) value, and total volatile basic nitrogen (TVB-N) content of pork/fish composite meatballs. The results showed that the contents of protein and fat in meatballs from groups 2-1 and 2-2 were lower than those in groups 3-1 and 3-2, and the contents of water, protein and fat were 61.68%, 11.32% and 19.41% for group 2-1, and 62.45%, 11.09% and 19.33% for group 2-2, respectively. The gel properties, hardness, elasticity, cohesion, and sensory quality of groups 3-1 and 3-2 were significantly higher than those of groups 2-1 and 2-2 (P < 0.05), but there was no significant difference compared with groups 1-1 and 1-2. The odor response value of groups 3 was lower than that of groups 1, and groups 3 had the highest sweetness value (3 039.66) and lowest bitterness value (534.59). The TBARs value and TVB-N content in groups 1-2, 2-2, and 3-2 (with washed fish paste) were significantly lower than those in groups 1-1, 2-1 and 3-1 (with unwashed fish paste) (P < 0.05). Since fresh fish paste is not easy to store and subject to spoilage, frozen washed fish paste with antifreeze agent can be used to produce composite meatballs.
ABSTRACT
Since the year 2020, the use of plastic as a strategy to mitigate the spread of COVID-19 disease has been given substantial attention. Global environmental contamination of plastic creates waste and is a known threat to soil ecosystems as a main sink of microplastics. However, there is still considerable uncertainty about microplastics controlling soil properties alteration. Therefore, we carried out an incubation experiment with soil and Carex stenophylla Wahlenb., which are the dominant soil and grass species in semi-arid regions. We investigated the effect of polymer polyethylene terephthalate (PET) concentrations (0%, 1%, 3%, and 5%) on C. stenophylla growth and soil ammonium-N and nitrate-N, organic matter content, pH, soil aggregates, and soil respiration. When soils were exposed to PET microplastics, fewer seeds germinated (62.8 ± 32%) but not significantly (p value > 0.05) when soils were treated to 0, 1, 3, and 0.5% PET. Shoot height was also not effectively reduced with PET. The soil pH was considerably lower when exposed to higher PET compared to all other treatments with the soil exposed to 5% w/w PET for both unplanted and planted, being 0.84 and 0.54 units, respectively, lower than the controls. The soil microbial respiration under exposure to PET was considerably increased in comparison to control samples. Moreover, the presence of PET resulted in potential alterations of soil stability, and with PET present soil stability increased. In conclusion, PET microplastics cannot significantly affect the development of C. stenophylla but could affect crucial soil properties. In addition, changes occurred with increased variability in soil ammonium-N and nitrate-N, particularly at a high PET ratio.
Subject(s)
Ammonium Compounds , COVID-19 , Ecosystem , Microplastics , Nitrates , Plastics , Poaceae , Polyethylene Terephthalates , Soil/chemistryABSTRACT
Growth of a fluid-infused patch on a thin porous layer, e.g. on a piece of paper or cloth, is related to the transmission of virus particles through exhaled droplets and aerosols. We present a theoretical model to describe how a wet patch develops gradually through imbibition, once a sessile droplet attaches at a permeable surface and drains gradually into a thin porous layer. Two limiting cases are considered based on different assumptions on the motion of the contact line during the coupled process of drop drainage and patch growth: (i) the apparent contact angle remains unchanged, so the radius of a sessile droplet decreases with time;and (ii) the location of the contact line remains pinned, so the contact angle decreases as time progresses. The model leads to evolution pathways for both the droplet and the fluid film within the porous layer, without introducing arbitrary fitting parameters. Potential implications of the model and its solutions are also discussed briefly in the context of the outspread of COVID-19, employing physical parameters for exhaled droplets, paper and cloth.
ABSTRACT
The use of disposable face masks increased rapidly among the general public to control the COVID-19 spread. Eventually, it increased the disposal of masks and their associated impacts on environmental pollution. Hence, this study aims to analyze the impact of nonwoven fabric structural parameters and weathering on the microfiber release characteristics. Spunbond polypropylene nonwoven with four different weights and meltblown nonwoven with two different weights were used in this study to analyze microfiber release at dry, and wet conditions to simulate improper disposal in the environment. Exposure to sunlight significantly increases the microfiber release from 35 to 50% for spunbond fabric and 56-89% for meltblown fabric. Weathering in sunlight structurally affected the tensile properties of the polypropylene fibers due to photodegradation. The study showed that each mask can produce 1.5 × 102 and 3.45 × 101 mg of microfiber/mask respectively in dry and wet states. In the case of structural parameters, a higher GSM (grams per square meter), abrasion resistance, bursting strength, and thickness showed a positive correlation with microfiber release in both fabrics. Significantly a higher microfiber release was reported with meltblown fabric than the spunbond for a given GSM. The presence of finer fibers and more fibers per unit area in meltblown fabric was noted as the main cause. Nonwoven fabric GSM and the number of fibers in a specific area showed a higher influence on microfiber release. Based on the mask consumption reported in the literature, India alone can produce around 4.27 × 102 tons of microfibers/week as an average of dry and wet conditions. The study suggests that the proper selection of physical parameters can significantly reduce the microfiber fiber release at all stages.
Subject(s)
COVID-19 , Masks , Humans , India , Polypropylenes , TextilesABSTRACT
Indoor air quality is increasingly recognized as a serious health hazard in many international environments. During the recent pandemic, this concern was amplified as Covid-19-related mortality closely correlated with poor air quality. Even a comparatively small decline in the Air Quality Index (AQI) can be linked to a sharp mortality increase. Worsening air quality levels are compounded by distinct air-quality issues in different geographical areas. In the face of this serious and wide-ranging threat, the common solution-introducing a high MERV-rated filter-comes up short, as these filters create back pressure that often exceeds the capacity of the HVAC systems in which they are installed. High-backpressure filters also use more energy and require frequent filter changes, making them more expensive to maintain and bad for the environment. This paper describes a new form of electrostatic filtration that is ideal for international markets since it has a uniform performance, low back pressure, is energy efficient, and can be tuned to perform at a range of filtration levels depending on demand. Developed at the University of Washington, the technology features porous electrodes that collect and hold, a large capacity of particles regardless of their size and physical properties. This paper will describe the technology, prototype testing, including a 6-month pilot installation, and will detail how the technology can be used to achieve on-demand MERV 15 filtration levels in systems that require continuous low back pressure and reduced energy consumption.
ABSTRACT
One of the important requirements for service robots is attracting people by attractiveness and to be able to exchange messages with people. With reference to the traditional Japanese puppet show, Ningyo Joruri, we have independently developed OSONO, which is a physical robot, with high-quality choreography. In this paper, we report questionnaire evaluations on OSONO targeting a puppeteer expert group and compare with existing questionnaire results targeting the ordinary person. This shows that the method of creating OSONO and its choreography is effective in widely general. Additionally, we develop a remote evaluations system so that we can conduct questionnaires of OSONO in a short time for more evaluators. We also verify the effectiveness of this remote evaluation system. This system can be expected as a substitute for the conventional face-to-face evaluation, which is becoming difficult to conduct it due to the pandemic of COVID-19. © 2021 IEEE.
ABSTRACT
Wastewater‐Based Epidemiology (WBE) is widely used to monitor the progression of the current SARS‐CoV‐2 pandemic at local levels. In this review, we address the different approaches to the steps needed for this surveillance: sampling wastewaters (WWs), concentrating the virus from the samples and quantifying them by qPCR, focusing on the main limitations of the methodologies used. Factors that can influence SARS‐CoV‐2 monitoring in WWs include: (i) physical parameters as temperature that can hamper the detection in warm seasons and tropical regions, (ii) sampling methodologies and timetables, being composite samples and Moore swabs the less variable and more sensitive approaches, (iii) virus concentration methodologies that need to be feasible and practicable in simpler laboratories and (iv) detection methodologies that should tend to use faster and cost‐effective procedures. The efficiency of WW treatments and the use of WWs for SARS‐CoV‐2 variants detection are also addressed. Furthermore, we discuss the need for the development of common standardized protocols, although these must be versatile enough to comprise variations among target communities. WBE screening of risk populations will allow for the prediction of future outbreaks, thus alerting authorities to implement early action measurements.
ABSTRACT
This article argues that guns, as objects used in and for crime, have received insufficient criminological attention. It proposes a socio-material perspective for taking crime guns seriously as material agents in the ways many serious crimes are planned and executed. Drawing in part upon affordance theory, the perspective links the ‘objective’ physical properties of guns to their allure and take up for the purposes of carrying out crime. Guns are powerful organising objects in the commission of crime, it is argued, capable of provoking as well as enabling a range of threatening and harmful activities. The perspective is developed drawing upon interview data from a large qualitative study of convicted gun criminals. These data enable the notion of materiality to be considered at different stages of criminal career, particularly prior to first criminal gun use through to enforced or voluntary desistance. The article concludes with a consideration of policy options suggested by the socio-material perspective. In a post-Covid 19 world in which guns have gained greater salience in many countries, it is argued that the need to ‘dematerialise’ gun attraction and use has never been greater.