This study presents a novel approach for characterizing the mechanics of flow in mildly meandering open channels, specifically focusing on the development of a new vertical distribution equation for transverse velocity. Unlike existing equations in the literature that rely on complex logarithmic or integral forms or infinite series forms, which are impractical for hydraulic engineers, the proposed equation employs ordinary power functions. This new formulation offers several advantages, including the consideration of previously neglected lateral forces resulting from wind and ship movement. Comparisons with available existing equations indicate a good agreement, highlighting the accuracy, sensitivity to roughness, and applicability of the developed transverse velocity equation. Notably, the analysis reveals that wind velocities can significantly increase transverse surface and bed velocities, emphasizing the importance of considering such factors in flow characterization. Moreover, the present approach yields higher transverse surface and bed velocities compared to a well-known existing equation. The equation for transverse velocity relies on two key assumptions. Firstly, it assumes a constant turbulent viscosity throughout the flow. Secondly, it relies on the condition that the topographic steering number is less than one, allowing for the approximation of mild curvature and meandering conditions. In addition, the developed transverse velocity equation is the only equation that offers derivation for an expression for the transverse boundary shear stress. This expression accounts for the effects of the centripetal force and the transverse pressure force, providing a comprehensive understanding of the flow dynamics in meandering channels. The study further presents distinct expressions for the deviation angles of the flow velocity and the bed shear stress, enhancing our understanding of the complex mechanisms governing flow behavior in meandering channels.
Biological pest control, often known as biological pest control or biocontrol, is a sustainable and ecologically friendly method of pest management in agriculture. It entails using living organisms, including predators, parasitoids, and diseases, to control pest populations and reduce agricultural loss. The study used the experimental method. The experiment was conducted in Al Batinah South Governorate from 2019-2021 to address crop loss and pesticide overuse in tomato and cucumber crops. Then, it was extended to Al Sharqiyah North, Ad Dakhiliyah, and Al Batinah North Governorates, using biological control methods like Green lacewing and Ladybird. The study used frequencies, percentages and standard deviations as statistical methods. The study employed the experimental method. In the current study, the researcher used certain natural enemies to test their effects on protecting tomato and cucumber crops in greenhouses from harmful pests in the Sultanate of Oman. The results revealed that Green lacewing and Ladybiboth both significantly eliminated whiteflies in tomato and cucumber crops by effectively controlling their populations. The study found that both the ladybird beetle and the green lacewing insect effectively reduced pest populations in tomato and cucumber plants over 10 days. The green lacewing insect led to an average reduction of 80% in pests, while the ladybird beetle was more effective, resulting in a 70% average reduction. Thus, the novelty of this research lies in its exploration of the use of natural enemies like the green lacewing and ladybird as a sustainable, eco-friendly alternative to chemical pesticides for controlling greenhouse pests, emphasizing the importance of sustainable pest management practices and integrating natural enemies with cultural practices and monitoring techniques.
Visible derivative spectroscopy was used to interpret the sediment and phytoplankton assemblages within the old woman creek natural estuarine reserve during the summers of 2016 and 2017. A Varimax-rotated Principal Component Analysis (VPCA) of reflectance data collected from four sampling sites in 2016 identified three Varimax-rotated Principal Components (VPCs): Diatom + Illite (2016-VPC 1), Dinoflagellate Algae + Cyanobacteria + Cryptophytes (2016-VPC 2) and Cyanobacteria + Illite + Dinoflagellate Algae (2016-VPC 3). Four leading components were identified from the VPCA of 2017 data collected from six sampling sites. These include a diatom + green algae + cyanobacteria (2017-VPC 1), suspended clay (2017-VPC 2) and two dinoflagellate algae communities, each of which was associated with sediments and cyanobacteria (2017-VPC 3 and 4). Significant correlations between chlorophyll-a versus 2017-VPC 1 and 2017-VPC 2 versus total suspended solids confirm these PCs' applicability as proxies for algal abundance and suspended material/sediments, respectively. During the wet 2017 sampling period, when the mouth bar controlling the flow from the estuary to Lake Erie was open; diatom, cyanobacteria and green algae abundance in the estuary declined immediately after rainfall and increased within two to three days as the estuary recolonized with phytoplankton transported from upstream. The inflow of storm water increased the concentration of insoluble clay minerals within the estuary but declined within two to three days. Suspended sediments were transported into the lake through the estuary when the mouth bar was open. As the mouth bar progressively narrowed towards the end of the 2017 sampling period, the amount of algae and suspended material transported into the lake declined and was more concentrated in the upstream sampling sites. Observed temporal and spatial variation of sediments demonstrates the significance of the estuary environments as natural sediment retention structures.
Microalgae play a crucial role in the aquatic food chain, climate change mitigation and economic applications. Several factors, such as light, temperature, nutrients, agitation and pollutants, can significantly influence their growth. In SPIE of its importance, there is a lack of research concerning the effects of agitation on the interaction between different pollutants and phytoplanktonic microorganisms. This study aimed to investigate the impact of agitation on the growth and cellular response of Tetraselmis sp. exposed to BP3 and polyethylene nanoparticles. Results showed that agitation significantly inhibited microalgae growth, in the presence of BP3 and nanoplastic. Considering photosynthetic pigments, there was a reduction in the concentration of Chl a under agitation, regardless of contaminants. Furthermore, Chl b concentrations remained unchanged across all experimental conditions. Additionally, a noticeable increase in carotenoid levels was observed in groups with higher concentration of BP3 (with agitation) and BP3 + NP (with or without agitation). An elevation in SOD and CAT enzyme activity was observed, indicating oxidative stress. But agitation did not impact MDA levels. These findings highlight the importance of considering agitation when evaluating the interaction of pollutants with planktonic organisms in toxicological studies, enhancing the understanding of environmental stressors in natural ecosystems.
The Torean hiking trail is the newest hiking trail in Mount Rinjani National Park (TNGR). Hiking ecotourism can be an environmentally friendly alternative in managing national parks; however, if it is not adequately supervised, overtourism will occur, degrading the environment and reducing the quality of the visitor experience. To prevent this, it is necessary to know the number of visits allowed by calculating the carrying capacity of the hiking trail and ensuring the capacity is maintained. The data processing technique uses the carrying capacity calculation method by Cifuentes with modifications and correction factors that are suitable for hiking tourism. The results showed that the Torean lama hiking trail (Torean post-Sembalun Torean junction) has a physical carrying capacity of 4,516 people/day, a real carrying capacity of 532 people/day, and an effective carrying capacity of 372 people/day. In comparison, the Torean Baru hiking trail (Birisan Nangka Sembalun Torean junction) has a physical carrying capacity of 4,165 people/day, a real carrying capacity of 333 people/day, and an effective carrying capacity of 233 people/day. The carrying capacity is higher than the actual visitation levels; therefore, tourism activities on the Torean hiking trail do not indicate over-tourism in terms of the number of visits.
Facemasks are widely used worldwide to prevent inhaling airborneparticles and viruses, especially after the outbreak of COVID-19. To assess theeffectiveness of various facemasks against PM10 and PM2.5,experiments with a mannequin head were conducted at 10 and 55 LPM airflowrates. A total of 38 masks, including 26 CMs, 7 SMs, and 5 N95 masks, weretested against PM10 and PM2.5 at 55 LPM airflow rate,while 18 masks, including 10 CMs, 6 SMs, and 2 N95 masks, were tested at 10 LPMairflow rate. The surface morphology of these facemasks was examined using asimple digital microscope of 0.3 M image sensor. SMs and N95 masks had smallerpore sizes and higher porosity, resulting in higher filtering efficiency. Incontrast, CMs had larger pore sizes and lower porosity, leading to poor filtering efficiency. Theaverage pore sizes of SMs and CMs were 70 μm and 160 μm, respectively, whiletheir porosities were 99 pores/mm2 and 20 pores/mm2, respectively. N95FFRshad an average pore size of 49 μm with a porosity of 88 pores/mm2. The averagefiltering efficiency of facemasks followed the order N95 FFRs > SMs >CMs. The Prototype Cloth Masks (PTCMs) were stitched using cottonfabrics with adjustable ear straps, nose pins, and polypropylene (PP) fabric asthe filter. Their filtering efficiency was found to be nearlyequivalent to N95 masks and their performance did not deteriorate even afterfive washing and drying cycles. This facemask can help reduce particulateexposure, particularly in developing countries with high air pollution, such asthe Kathmandu Valley.
The global resilience nexus: Forging a sustainable future presents a groundbreaking framework designed to enhance global resilience through interconnected components. At its core is the cultivation of inclusive community networks, fostering collaboration, engagement and collective action. By uniting policymakers, practitioners and community members, the framework facilitates the co-creation of robust solutions. Knowledge sharing and mapping play a pivotal role, enabling the exchange of best practices, lessons learned and inventive ideas. This aids in identifying knowledge gaps, directing resilience-building efforts and fostering a culture of mutual learning and cooperation. The framework explored the intricate relationship between climate change and migration, focusing on vulnerable regions like Puerto Rico, Haiti, Senegal, Moldova and Bangladesh. By delving into the experiences of these communities, it aimed to devise strategies addressing challenges in environmental change, population dynamics, human security and public policy. The goal was to amplify adaptive capacities, reduce vulnerabilities and foster sustainable solutions for climate-induced migration and host communities. Acknowledging the pivotal role of minerals in the transition to renewable energy and the digital economy, the framework confronted associated risks like environmental degradation and social disparities. Through cross-regional and cross-sectoral stakeholder dialogues, it fostered consensus-building for policies that advance a more resilient supply chain, emphasizing environmental, social and governance considerations. Another facet addressed the convergences of environmental change, security and conflicts, scrutinizing how environmental stressors contribute to conflicts and human insecurity. The framework examined the role of sustainable environmental practices in conflict prevention and peacebuilding, aiming to cultivate a more resilient and peaceful world. Finally, it tackled global food insecurity exacerbated by climate change, inflation, the COVID-19 pandemic and geopolitical tensions. Recognizing the need to fortify agricultural systems and enhance access to nutritious food, it aimed to amplify resilience through sustainable agriculture practices, innovative food production methods and inclusive policies, ensuring food sovereignty for all.
COVID-19 disease causes millions of human deaths and huge economic losses throughout the world. To limit the disease transmission numerous attempts have been made. Several studies observed associations of weather values on COVID-19 transmission. In the current study, the impacts of weather parameters on daily COVID-19 incidences have been examined in eight different cities in Bangladesh. For this purpose, a whole one-year data set of daily COVID-19 laboratory tests and tested positive identified counts have been collected from the daily press releases of the director general of health services, Dhaka, Bangladesh for all the cities. From these data sets a percentage of positive identified rate has been calculated. As well as daily weather parameter values for all the cities have been collected from the website of world weather online for the whole year. Spearman rank correlation and quasi-poisson generalized linear model have been applied in the daily weather and COVID-19 percentage of positive identified data sets to find associations between them. Significant stable negative impacts have been observed for maximum temperature (correlation estimate: -0.25 to -0.50; model estimate: -0.15 to -0.30) and air pressure (correlation estimate: -0.10 to -0.40; model estimate: -0.08 to -0.17) in both analyses. Mixed (positive, negative, and no) effects have been noticed for other weather factors (humidity, rain, wind speed, minimum temperature, and cloud) on COVID-19 cases. Also, weekly variations of COVID-19 and weather values have been examined here. Comparatively lower values have been observed for maximum temperature during December-February and for air pressure during May-August. Hence, January-February due to lower temperatures, and July-August due to lower air pressure might be more sensitive seasons to the COVID-19 outbreak in Bangladesh. These findings might help the decision-makers of the country to initiate necessary steps before the COVID-19 seasonal outbreak.
