Plastic Ones Research Articles

Performance assessment of a high-efficiency indirect dew-point evaporative cooler through three-dimensional modeling

The escalating demand for eco-friendly air cooling, driven by concerns over global warming, necessitates sustainable alternatives to air conditioners. Dew-point evaporative coolers offer a green alternative yet face challenges due to high flow resistances caused by the U-turn of the working air. Recently, we have developed a new compact counterflow dew-point cooler that eliminates the U-turn of the working air, mitigating flow resistance. In this paper, a precise three-dimensional simulation, based on fluid dynamics, heat transfer and mass transportation, is developed to assess the cooler's performance. The validation against experiments shows maximum 8 % deviation in input pressure and 3 % in product air temperature. The simulation provides insights into the cooler's operation, efficiency, and performance, which are not easily obtained experimentally. Optimal cooling coefficients of performance occurs at working ratios of 0.5–0.6. Notably, while metallic channel separator excels at higher flow rates, plastic ones like high-density polyethylene and polycarbonate match performance at lower rates. Furthermore, the cooler performs better in hotter, drier climates. In locales like Xian and New Delhi, the cooler is suitable for standalone use, while in regions like Dubai, Texas, Singapore, Beijing, and Monterrey, it can be coupled with air conditioners to enhance the ventilation and energy efficiency.

Nutrients removal in overloaded WWTP by intermittently aerated IFAS: Effects of biofilm carrier and intermittent aeration cycle

Updating of the current Urban Waste Water Treatment Directive (91/271/EEC) will demand stricter regulations for nutrients removal. In this frame, wastewater treatment plants (WWTPs) of small-to-medium potential will face new challenges for achieving process intensification. Integrating intermittent aeration (IA) and integrated fixed-film activated sludge (IFAS) technologies could be a promising solution to meet such requirements. This study analyzed how IA cycles affected nutrients removal in IFAS reactors with different biofilm carriers (e.g., plastic and sponge media). The plants responses to different carbon/nitrogen/phosphorous (C/N/P) ratios were evaluated while operating under low sludge retention time (SRT) to simulate overloaded conditions.A short IA cycle (1 h) with an aeration/not aeration ratio of 2:1 enabled high organic carbon and nitrification performances when operating at high C/N/P (11.8/1/1), whereas low denitrification and phosphorous removal yields were obtained because of the short not-aerated phase. Decreasing C/N ratio (8.8/1/1) without changing the IA cycle resulted in nitrification worsening because of the reduced metabolic kinetics of biofilm. Under such load conditions, a higher IA cycle (2 h) was necessary to improve process performance. A longer not-aerated phase was also positive for denitrification and phosphorous removal because of the establishment of anoxic and anaerobic environments within the bulk and inner biofilm layers. Besides, results suggested that sponge carriers offered advantages over plastic ones, enabling a higher biofilm retention capacity, better nutrient removal, as well as robustness and resilience to operating condition changes. This would result in simpler management systems for implementing the IA process, thus reducing process complexity and costs.

Moment capacity for steel and recycled waste plastic ducts in post-tensioned beams

Generally, in post-tension construction practices, the contractors tend to use galvanized steel ducts for cost and availability reasons. An experimental study was conducted on two duct types, galvanized steel, and recycled waste plastic. Four post-tensioned beams (PTB) were prepared 7.87 in. (200 mm) wide, 11.8 in. (300 mm) deep, and 16.40 ft (5000 mm) in length. Different parameters were used to clarify the advantage of recycled waste plastic ducts against galvanized steel. The PTB, provided with strands of 0.5 in. (12.7 mm) diameter, were tested up to flexural failure using 3 points bending machine. Minimum reinforcements were used to reinforce the PTB and resist the applied loads. The moment capacity results were compared to ACI provisions. The lower friction related to galvanized steel ducts as opposed to those of recycled waste plastic ones gives a result with a significant reduction in prestressing steel needed, regardless of the length of the system. However, it was proved that there is no loss of moment capacity by using recycled waste plastic ducts. The experimental studies were modeled using finite element software to compare the obtained results. A good correlation was noticed between both experimental and numerical results. This paper shed light on the advantages of using recycled waste plastic ducts such as corrosion resistance, lightweight, friction losses, and durability. However, the use of recycled waste plastic materials for manufacturing plastic ducts contributes effectively to sustainability and saving the environment and natural steel resources.

(196) Assessing Treatment Outcome of Primary Vaginismus Using Vaginal Dilators Among Women in Saudi Arabia

Abstract Introduction Vaginismus is a pain disorder in which it is difficult to achieve vaginal penetration due to involuntary vaginal muscle spasms. It can occur during intercourse, vaginal examination, or insertion of a menstrual cup or tampon. Risk factors include family history, negative sex views, and cultural influences such as the value placed on the hymen. Moreover, fear of pain, injury, bleeding, and losing control can play a role in the development of vaginismus. Women with vaginismus are primarily treated with gradual desensitization to penetration using vaginal dilators. However, studies that record therapy duration and success are lacking the literature. Objective This study aims to assess the success rate of gradual exposure therapy to penetration using vaginal dilators for the treatment of primary vaginismus. Methods Women diagnosed with primary vaginismus between August 1st, 2019, and December 31st, 2021 at a tertiary care center in Jeddah, Saudi Arabia were included in this study. Those under 18 and those who did not use vaginal dilators were excluded. The primary investigator collected data by contacting participants over the phone to fill out a validated questionnaire, including questions from Female Sexual Function Index (FSFI) and Pain Anxiety Symptom Scale Short Form 20 (PASS-20). We project a total number of 50 participants at the end of the recruitment period by August 31, 2022. Data is collected on paper and entered into STATA 17. Demographic data included age, duration of the marriage, presence of romantic relationship prior to marriage, and education level. Our primary outcome is the degree of treatment success according to pain level and frequency scores during and after intercourse. Results The sample included 16 eligible patients. The mean age was 28.9 years (SD +/− 3.6). Almost all participants had a bachelor's degree or higher. 70% were married for two years or less with about 37% who were married for one year or less. 70% reported having a romantic relationship before marriage. We excluded 4 patients from further analysis who had never used vaginal dilators before. 33% of those who used vaginal dilators did not report any pain during or after intercourse. Only 37.5% of those who reported pain during or after sexual intercourse stated that the pain prevented them from having sexual intercourse. Among women who had sexual intercourse, 63% suffered moderate to a very high level of pain during intercourse and 25% experienced low to moderate pain after intercourse most of the time. Approximately 83% reported treatment success with vaginal dilators, while only 17% reported no success. The largest dilator size used was 6 (27%), and the most used plastic ones (50%). About 58% preferred conducting dilation therapy sessions at home instead of the clinic. Conclusions According to our findings, more than 80% reported success with vaginal dilators for treating primary vaginismus despite still experiencing pain during or after intercourse. Interestingly more than half of the patients preferred doing exercises at home, contradicting previous studies pointing out that one session with the therapist can predict higher success in treating vaginismus. Disclosure No

A word of caution regarding breast milk: a correspondence

Properties such as durability, flexibility, plasticity, and low cost of production have led to plastics being widely used in a variety of consumer products. Global plastic production is estimated to be 370 million tonnes out of which two thirds are being manufactured in Europe and Asia1. Through atmospheric agents and photooxidation with bacteria, plastics degrade into microparticles called microplastics (MPs)2,3. Particularly, MPs enter the body through respiration, ingestions, and dermal contact. They have a myriad of harmful inflammatory effects, oxidative stress, and an increased risk of allergic diseases2,4. Studies have shown MPs are a major concern when pregnant women are exposed to foreign bodies that may reach the placenta and have adverse effects on the fetus2,3. Previously, MPs have been found in organs such as the liver, spleen, kidneys, and placenta2,3. However, a recent study by Ragusa and colleagues has identified traces of MPs in breast milk. Ragusa and colleagues evaluated 34 breast milk samples using Raman Microspectroscopy and found MPs in more than 75% of the samples (26/34)2. Both placenta and breast milk contain traces of MPs that raises risks for neonates constantly exposed to the toxic particles. Specifically, the Plasticenta study by Ragusa et al3 identified MPs originated from plastic/rubber found in a variety of products women use such as cosmetics, foundations, nail polish, textile (cotton/polyester), fragrances, lipstick, mascara, and eye shadows. Therefore, pregnant women should resort to using organically produced cosmetics that will limit toxin exposure. Should mothers stop breastfeeding completely, knowing that there are MPs in breast milk? The benefits of breastfeeding outweigh the risks that breast milk contains the best standard of nutrition that enhances the immune system and growth of the infant. Some suggestions to counter the presence of these foreign bodies can be the use of paper bags instead of plastic bags, glass bottles instead of plastic ones, and finally raising public awareness and promote laws that reduce plastic pollution in the environment. Healthcare professionals should strive to educate mothers on limiting the use of toxic elements present in cosmetics. A relevant question to ponder is where can MPs accumulate the most in the body. Currently, there is a scarcity of knowledge on how MPs accumulate in humans and which organ yields the highest content of the toxin. Therefore, apart from breastmilk containing traces of MPs, there is insufficient research on the pathological problems that neonates could potentially face in the future with regard to development or even organ damage. Ethical approval None. Sources of funding None. Author contribution M.I.S.: Conceptualisation, literature review, writing - original draft, writing - reviewing and editing. A.R.S. and T.Z.: Literature review, writing - original draft, writing - reviewing and editing. S.A.S.: Writing, reviewing and editing. Conflict of interest disclosures The authors declare that they have no financial conflict of interest with regard to the content of this report. Research registration unique identifying number (UIN) None. Guarantor Moeez I. Shiraz. Consent None. Provenance and peer review Not commissioned, externally peer reviewed.

Fast-food packaging can emit volatile PFAS

Compostable fast-food containers, designed to be more environmentally friendly than single-use plastic ones, can release toxic per- and polyfluoroalkyl substances (PFAS) into the air, according to an analysis of samples from retailers in Toronto ( Environ. Sci. Technol. Lett. 2023, DOI: 10.1021/acs.estlett.2c00926 ). The results suggest that polymers with fluorinated side chains, which are used to make paper-based food packaging grease resistant, break down over time into volatile fluorotelomer alcohols and fluorotelomer methacrylates. Researchers screened 42 samples—including molded fiber bowls, burger wrappers, and popcorn bags—for total fluorine content. The molded fiber bowls contained the highest levels. Analysis of eight of the samples revealed up to 14 PFAS in each. The most abundant PFAS in all but one of the eight samples were 6:2 fluorotelomer alcohol and 6:2 fluorotelomer methacrylate. Surprisingly, total PFAS levels dropped by up to 85% after the products were stored for 2 years, says Marta Venier ,

A Biodegradable Stereo-Complexed Poly (Lactic Acid) Drinking Straw of High Heat Resistance and Performance.

Current biodegradable drinking straws suffer from poor heat resistance and rigidity when wet, causing user dissatisfaction. Here, a fully biodegradable straw formed by stereocomplexation of poly (lactic acid) (SC-PLA) is reported. Because of the unique strong interaction and high density of link chains between stereocomplex crystallites (over 70% crystallinity), SC-PLA straws outperform their counterparts on the market. This coupled with the advantages of simple processing (solution casting and annealing) and relatively low cost (~2.06 cents per straw) makes SC-PLA drinking straws a superior substitute for plastic ones. Commercially available PLLA straws lose almost 60% of their flexural strength when wet compared to less than 5% of the SC-PLA straws proposed in this study.

Bioactive Vitamin C Content from Natural Selected Fruit Juices

The content of vitamin C in fruit juices can be lowered by alterations in storage and temperature. This study compared storage circumstances (temperature, duration, and packaging type) to determine which variable had the biggest influence on changes in the vitamin C content of juices (grapefruit, mandarin, peach, apple, pear, plum). Fruit juices held in glass (plastic) containers at 4 °C saw vitamin C losses in the range of 0.0–10.9% (2.4–17.4%) in 24 h, 1.4–22.6% (5.2–25.3%) in 48 h, and 2.8–37.0% (6.0–39.0%) in three days. By raising the storage temperature to 23 °C, vitamin C losses in glass (plastic) containers were found to be 1.4–19.1% (5.2–22.2%), 2.8–20.9% (5.9–25.9%), and 4.5–43.5% (6.0–38.7%) of the value after 24 h, 48 h, and three days, respectively. When decreasing the temperature to −18 °C in fruit juices stored in glass (plastic) containers, there were losses of vitamin C in 24 h in the range of 1.5–19.6% (3.0–20.0%), in 48 h, 4.5–26.1% (4.5–26.1%), and in three days, 6.0–43.1% (5.8–43.5%) of the value. The effect of temperature on vitamin C concentration has been proven. Fruit juice’s vitamin C is more stable when kept in glass containers as opposed to plastic ones, which have a limited shelf life.

Comparative Study about Dimensional Accuracy and Surface Finish of Constant-Breadth Cams Manufactured by FFF and CNC Milling

In this work, the design, manufacture and measurement process of constant-breadth cams is presented. The motion law of the cam was designed by means of Bézier curves and the corresponding design desmodromic constraints. The cams were manufactured in two different materials employing two different processes: PLA cams with fused filament fabrication (FFF) and aluminium cams with computer numerical control (CNC) milling. The main aim of this work is to compare both types of cams regarding dimensional accuracy and surface finish, in order to evaluate if it would be possible to temporally replace a metallic cam with a plastic one during the repair of the first one. Dimensions were measured with micrometres and surface roughness with a contact roughness meter. The results show that, in diametral dimensions, similar dimensional error values were obtained for both the 3D-printed and the machined cams. However, in longitudinal dimensions, whose direction is perpendicular to the 3D-printed layers, the 3D-printed cams showed higher dimensional error than the machined ones. The average roughness Ra in the 3D-printed cams was 20 times higher than in the milled cams. According to the results, it would be recommended to temporally replace metallic cams with plastic ones in applications of low-power transmission. Given that in the literature little information is available about the measurement of 3D-printed desmodromic cams, this work will contribute to the study and analysis of this kind of 3D printed mechanism.

Active packaging of chitosan film modified with basil oil encapsulated in silica nanoparticles as an alternate for plastic packaging materials

Active packaging based on biomaterials and essential oils is an alternate for plastic ones. But, essential oils are chemically and physiologically labile, and they have strong scents, limiting their use as antimicrobial additives in food. Thus, in this investigation, basil oil was encapsulated in silica nanoparticles (basil oil@SiNPs) and combined with chitosan films (basil oil@SiNPs@chitosan). Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), surface area and Brunauer-Emmett-Teller (BET) analysis, encapsulation and loading % were used to evaluate basil oil@SiNPs. The surface area of SiNPs decreased from 59.006 to 43.86 cm2/g due to basil oil encapsulation. The encapsulation and loading % were 81.96, 65.87, 48.48 and 43.13, 37.64, 33.44% for 2, 1.5, and 1 mL of basil oil, respectively. Fourier-transform infrared (FT-IR), XRD, thermogravimetric analysis (TG), mechanical, wettability, water vapor permeability (WVP), oxygen permeability (OP) features; water vapor sorption isotherms and antimicrobial inhibition tests were used to describe the produced basil oil@SiNPs@chitosan films. Water contact angles and activation energy increased from 89.0° to 110.9° and −11.97 to −20.40 kJ/mol, respectively after addition of basil oil@SiNPs. However, WVP decreased from 5.9580 × 10−1±0.33 to 4.2413 × 10−1±0.55 g.mm.m−2.h−1.kPa−1 and OP increased from 4.094 × 10−4±0.52 to 6.715 × 10−5±0.32 (g.m−2.day−1.atm−1). The four models Guggenheim–Anderson–de Boer (GAB), Smith, Henderson and SIPSI were suitable for describing the moisture sorption of basil oil@SiNPs@chitosan films. Basil oil@SiNPs has antimicrobial inhibition against Gram positive and negative bacteria, pathogenic yeast.

Citric acid cross-linked curcumin/chitosan/chickpea flour film: An active packaging for chicken breast storage

Since there has been an increasing interest in natural, non-toxic, and biodegradable food packages instead of plastic ones, scientists put great effort into eliminating the potential drawbacks of these biodegradable films. In this study, citric acid (CA) was utilized as a crosslinker for the films produced by chitosan (CS), chickpea flour (CF), and active agent curcumin (CUR) by a solvent casting technique. CA was introduced into the film formulations at different concentrations (0, 0.5%, 1%, 1.5% w/v), and the influence on the functional film characteristics were extensively analyzed.Increasing CA concentration in formulation caused a reduction in water vapor permeability (WVP) of the films such that the film with the highest CA concentration (1.5-CUR/CF/CS) was 62.6% more resistant to water vapor than film without CA (0-CUR/CF/CS). When CA concentration in the film formulation was increased, elongation at break (EAB) value increased from 1.64% ± 0.13%, to 11.1%± 1.21% whereas tensile strength (TS) value decreased from 7.83± 0.08 MPa to 3.58± 0.20 MPa. Contrary to expectations, antioxidant activity of the films decreased with increasing CA concentration. X-Ray Diffraction (XRD) patterns of the films proved the amorphous nature and inhibitory characteristic of CA against retrogradation. In addition to all these, CA concentration significantly influenced Thermogravimetric analysis (TGA) pattern of the films with the increasing number of degradation stages. Besides the cross-linker characteristic of CA, it also extensively enhanced the antibacterial characteristic of the films. Films formulated with 1.5% (w/v) CA (1.5-CUR/CF/CS) showed antibacterial effect against both Escherichia coli (E.coli) (ATCC 11229) and Staphylococcus aureus (S.aureus) (ATCC 43300). Finally, chicken breast packed with 1.5-CUR/CF/CS films remained below unacceptable microbial threshold limits even at the end of the 9th -day of storage compared to samples packaged with the film with no antibacterial activity.

What Hinders the Development of a Sustainable Compostable Packaging Market?

Numerous publications and expert reports indicate plastic pollution as a widespread environmental problem. About 10 million tonnes of litter end up in the seas and oceans each year. It is estimated that 80% of all litter in saltwater is mainly plastic food packaging. Facing this challenge compostable packaging seems to be an alternative to conventional plastic ones and a feasible solution. Despite the environmental opportunities of the packaging produced from bio-based biodegradable polymers, the compostable packaging market is growing relatively slowly. Therefore, the aim of the paper is to recognize the key factors hindering the expansion of the food compostable packaging market for sustainable development. To achieve this objective 29 in-depth interviews with respondents of the key groups of biopackaging market stakeholders were conducted. The results of the qualitative study allowed us to identify environmental, economic, social, and governance barriers in the light of four main problems disrupting compostable packaging market development. This is an important contribution to the business and academic discussion on the importance of compostable packaging in achieving sustainable development goals as well as implementing the circular economy concept. The paper is the effect of the international R&D project.

Revealing the feasibility and environmental benefits of replacing disposable plastic tableware in aviation catering: An AHP-LCA integrated study

Reducing disposable plastic products has been in the spotlight lately, in order to address plastic pollution. With the rapid development of air transportation, plastic waste during flight is increasing, and most of it comes from catering. To evaluate the feasibility of replacing disposable plastic tableware, we carried out an integrated analytic hierarchy process (AHP) - life cycle assessment (LCA) study. The results show no significant feasibility in replacing salad bowls, while cutleries made of stainless steel, bamboo or bio-based plastic are preferred to petroleum-based plastic ones. In particular, bio-based plastic cutlery poses the least negative environmental impacts among all the disposable alternatives. Stainless steel cutlery will have the least carbon emissions when used more than 29 times. Replacing cutleries can reduce carbon emission by 12.5 g to 25.6 g of CO2 per cutlery set, leading to a maximum reduction of 10,219.51 t/a in China's domestic flights in 2019.

Does the Element Availability Change in Soils Exposed to Bioplastics and Plastics for Six Months?

Plastic sheets are widely used in farming soil to improve the productivity of cultures. Due to their absorption capacity, plastic sheets can alter element and metal content in soils, and in turn affect soil properties. The use of biodegradable films is an attractive eco-sustainable alternative approach to overcome the environmental pollution problems due to the use of plastic films but their impacts on soil are scarcely studied. The aim of the research was to evaluate the impact of conventional plastic and bioplastic sheets on total and available concentrations of elements (Al, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn) in soils. The research was performed in mesocosm trials, filled with soil covered by conventional plastic and bioplastic sheets. After six months of exposure, soils were characterized for pH, water content, concentrations of organic and total carbon and total nitrogen, and total and available Al, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn element concentrations. The results highlighted that soils covered by bioplastic sheets showed higher total and available concentrations of elements and higher contamination factors, suggesting that bioplastic sheets represented a source of metals or a less-effective sink to these background metals in soils, compared to conventional plastic ones.

Plastic Purity and Sacred Dairy

By investigating the growing use of plastics within Mongolian dairying, this paper explores emerging microbial/social assemblages as they relate to local and imported ideas of purity and hygiene. Although many Mongolian herders prefer to use dairy equipment made from materials such as wood and hide, these items are increasingly being replaced by plastic ones. As new infrastructure connects northern herders to more extensive markets, it presents challenges for herders and for the microbial communities with whom they co-exist, placing herders under increasing pressures to compete with large-scale dairy enterprises that brand, package and distribute standardised dairy products. Looking at the changing material culture of Mongolian dairying and its relationships with microbial communities, this paper examines two emergent notions of purity: the first in which sterility is generated and contained and the second in which living dairy is harnessed and grown.

Productivity and parameters of adaptability of collection specimens of the cocksfoot

Relevance.The cocksfoot (Dactylis glomerata L.) remains an agricultural crop of high fodder value for the Komi Republic, grown both in pure form and as one of the components in grass mixtures. This forage grass is recommended for use in hayfields and pastures, being high-yielding, retaining for a long time in grass mixtures, growing quickly after mowing and grazing.Methods.In the collection nursery of the Institute of Agrobiotechnology named A.V. Zhuravsky of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences (Komi Republic, Syktyvkar), from 2016 to 2018, promising populations of cocksfoot of various ecological and geographical origin were studied by economic characteristics and parameters of adaptability, obtained from the world collection of Federal research center «N.I. Vavilov all-Russian Institute of Plant Genetic Resources – VIR»: 11 from the Northwestern Federal District of Russia (Komi Republic, Arkhangelsk, Pskov and Leningrad regions), 3 from the Ural Federal District (Tyumen and Sverdlovsk regions), 1 from the Siberian Federal District (Tomsk Region), 4 foreign samples from Northern Europe (Norway, Finland) and North America (Canada). The purpose of the research is to evaluate the yield indicator of green mass of specimens of cocksfoot in the collection nursery, to establish the parameters of adaptability and, on their basis, to select the most promising numbers for further breeding work. During the growing season during the years of research, various meteorological conditions were noted, which reflected the unstable nature of the fallout and distribution of precipitation, which made it possible to comprehensively evaluate the specimens of the cocksfoot and give them a more objective assessment based on the prevailing external environmental conditions.Results.As a result of research, it was found that according to a set of economically valuable parameters, specimens 45945, 47268 and 41826 were identified with a yield of green mass on average for two cuttings of 205–237 c/ha. Based on the obtained parameters of adaptability, specimens 36684, 47268, 33392 are classified as the most stable and plastic ones, which represent a valuable source material for further study and breeding work.

Detection and identification of potentially infectious gastrointestinal and respiratory viruses at workplaces of wastewater treatment plants with viability qPCR/RT-qPCR

This study aimed to qualitatively and quantitatively assess the prevalence of the most common respiratory and gastrointestinal viruses in the air, surface swab, and influent/effluent samples collected in wastewater treatment plants (WWTPs). Application of qPCR/RT-qPCR (quantitative polymerase chain reaction/reverse-transcription quantitative polymerase chain reaction) assays combined with PMA (propidium monoazide) dye pretreatment allowed detecting the potentially infectious and disintegrated viral particles in collected samples. In the air at workplaces in WWTPs, the most frequent isolation with the highest concentrations (reaching up to 103 gc/m3 of potentially infectious intact viral particles) were observed in case of adenoviruses (AdVs) and rotaviruses (RoVs), followed by noroviruses (NoVs). Viruses were significantly more often detected in the air samples collected with Coriolis μ impinger, than with MAS-100NT impactor. The temperature negatively (Spearman correlation: –1 < R < 0; p < 0.05), while RH (relative humidity) positively (0 < R < 1; p < 0.05) affected airborne concentrations of potentially infectious viral particles. In turn, the predominant viruses on studied surfaces were RoVs and noroviruses GII (NoV GII) with concentrations of potentially infectious virions up to 104 gc/100 cm2. In the cases of SARS-CoV-2 and presumptive SARS-CoV-2 or other coronaviruses, their concentrations reached up to 103 gc/100 cm2. The contamination level of steel surfaces in WWTPs was similar to this on plastic ones. This study revealed that the qualitative and quantitative characteristics of respiratory and gastrointestinal viruses at workplaces in WWTPs is important for proper exposure assessment and needs to be included in risk management in occupational environment with high abundance of microbial pollutants derived from wastewater.

Evaluation of Ecological Factors Regarding the Use of Disposable Containers among Khomeini Shahr Residents:A Qualitive Study

Introduction: Excessive consumption of disposable containers, and specifically the plastic ones, has adverse effects on ecosystem and the community's health. To identify ecological factors (individual, interpersonal and social) related to these containers, this study aimed to specify the most important factors according to the participants. Methods: This was a qualitative content analysis conducted through interviews with participants in different age and gender groups in Khomeini Shahr, Esfahan, in 2021, and continued until data saturation with 37 participants was reached. Data analysis was performed by qualitative content analysis method, based on the steps suggested by Elo in MAXQDA20 software. Results: The results demonstrated that the factors affecting the use of disposable containers were divided into two main categories of individual factors including four subcategories: preferences and priorities, personal beliefs, information and knowledge, fear and negative emotions. The interpersonal and social factors included nine subcategories: force of using, conflict between economic advantages and health, features and efficiency, putting foodstuff in disposable containers, hygiene elements related to health, factors related to families, social norms, the effect of advertisements, and increasing places using disposable containers. Conclusion: The results of this study indicated that comfort of use, being light and unbreakabl, ease of transportation, welfare and observing hygiene issues increased the use of containers, but paying attention to the health issues and effective educational sessions on the proper consumption of these disposable containers, can decrease the use of these containers.

CHANGE OF ENERGY CHARACTERISTICS OF LITHOSPHERE ELEMENTS DURING THEIR DEFORMATION

Purpose. The purpose of this study is to establish analytical patterns for predicting changes in stress and energy density spent on the destruction of rocks according to experimental studies. To solve this purpose in the article were set the following scientific problems: 1) analytical description of the dependence of the stress σij on the main deformation εij; 2) establishment of calculation parameters that are included in the analytical patterns; 3) analytical description and study of fracture energy density curves.&#x0D; Methodology. In the course of analytical and experimental researches of full diagrams of deformation of rocks the mathematical model of dependence of the stress on the deformation is developed. Physico-mechanical processes of all characteristic sections of the complete deformation diagram were also analyzed and described. Analysis of the resulting curve showed that the rock mass and elements of the lithosphere are not perfectly elastic or plastic objects. Along with the elastic ones, plastic ones are always present to one degree or another.&#x0D; The integration of the obtained analytical expression σ11 = f(ε11) allowed to establish the volumetric energy density spent on the destruction of the rock sample under the action of external load. The maximum activation energy for the considered rock is 0.67 MJ/m3. A comparison of the experimental and calculated values of the energy dependence u(ε1) shows a coincidence over almost the entire range of deformation changes (ε11 = 0..0.04).&#x0D; Findings. The study of rock samples at hard stress allowed to obtain a complete deformation characteristics of the rock. The curve that surrounds the deformation cycles (1) combines pre-boundary, boundary, extremal modes of deformation and destruction of rocks. Equation (4) allows us to establish that the destruction can occur at different values of energy density U(ε).&#x0D; Originality. An analytical description of the energy diagram of deformation and a complete diagram of stress change in the form of a single dependence, which takes into account the boundary and extremal areas, was developed in the work. In contrast to the method of piecewise linear approximation, this approach corresponds to the physics of the process and reduces errors in calculations.&#x0D; Practical implications. Theoretical and experimental analysis of the obtained energy fracture diagrams and complete stress change diagrams in rocks allows to estimate the bearing capacity of a rock mass or other solid body. This allows you to predict critical values of stresses and external loads to prevent failure in a timely manner.

Effect of delayed elective surgeries during COVID-19 pandemic

The field of surgery has been greatly affected during the pandemic due to the shift of resources to manage the huge numbers of COVID-19 cases. In this study, we aim to review the effect of the COVID-19 pandemic and lockdown measures on elective surgeries and the subsequent complications, in addition to the previously announced preparations and precautions for performing surgeries whenever indicated. Preparations include the availability of resources and performing each surgery in separate rooms away from other wards within the hospital to prevent any possibility of nosocomial infections. Moreover, limiting the number of individuals within the operation room and wearing personal protective equipment should be done. Limiting hospital visits and reducing in-hospital stays is also recommended. Regarding cancer operations, malignant tumors that were indicated for surgeries cannot be postponed. However, other non-malignant ones can be delayed depending on the pathologist's perspective and the symptomatology of the tumor. Besides, other surgeries like plastic and reconstructive ones can be re-scheduled. Additionally, most surgeries like urologic, orthopedic, and neurological operations can be delayed unless they are associated with a life-threatening lesion that can only be healed by surgical interference. On the other hand, palliative surgeries aiming to manage obstructions of the gastrointestinal tract cannot be delayed.