The current investigation is deliberated the flow and heat transfer of a shear thinning fluid over a non-linear stretching sheet has variable thickness. All rheological aspects at low to high shear ...rates are accounted theoretical by using generalized Carreau model of viscosity. Theoretical flow model is formulated for boundary layer phenomena by applying boundary layer approximations and then convert it from partial differential equations to ordinary differential equations with the help of similarity transformations. The solution is obtained by numerical method and the result are displayed in the form of velocity and temperature profiles under impact of rheological and geometrical governing parameters. In addition, the results of skin friction coefficient and Nusselt number are obtained under effects of these parameters. It is found that Nusselt number is significantly decreased when stretching is increased by velocity index parameter.
This study identifies the management functions performed in non‐profit ecosanctuaries relevant to tourism in New Zealand. Following a pragmatic qualitative approach, semi‐structured interviews in and ...pertaining to eco‐sanctuaries were conducted. The findings are contextualised using principal‐agent and stewardship theory. The results reveal that non‐profit ecosanctuaries fulfil various functions alongside their core tasks, restoration and conservation. These are education and engagement with the volunteers, local community, and external stakeholders. Dependence on external funding and support is crucial for ecosanctuary management decision‐making. Lack of funding, among other factors, means that, in some instances, non‐profit organisations go beyond their core mandate by adding tourism as a commercial component to their activities. In doing so, these organisations commit to and undertake tasks such as visitor management, visitor impact management and tourism product development.
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Diese Studieidentifiziert tourismusrelevante Managementfunktionen in lokalen non‐profit Naturschutzgebieten (‘ecosanctuaries’) in Neuseeland. QualitativeDaten wurden in Interviews erhoben. Die Ergebnisse werden mithilfe von principal‐agent theory sowie stewardship theory erklärt und kontextualisiert. Neben den Kernaufgaben in Renaturierung und Konservierung werdentourismusrelevante Funktionen in Bildung, Einbindung freiwilliger Mitarbeiter, lokaler Gruppen, sowie externer Akteure wahrgenommen. Die Abhängigkeit vonexterner Finanzierung und Unterstützung beeinflusst Entscheidungen des Managementsund bestimmt die Priorisierung von Naturschutz oder Tourismusfunktionen. Mangelnde Finanzierung führt neben anderen Faktoren dazu, dass gemeinnützige Organisationen in einigen Fällen über ihr Kernmandat hinausgehen, indem sie denTourismus als kommerzielle Komponente zu ihren Aktivitäten hinzufügen. Dabeiverpflichten sich diese Organisationen zu Aufgaben wie Besuchermanagementund/oder Produktentwicklung.
Polyvinyl alcohol (PVA) is an important industrial chemical, which is used in numerous chemical engineering applications. It is important to study and predict the flow behavior of PVA solutions and ...the role of nanoparticles in heat transfer applications to be used in chemical processes on industrial scale. Therefore, the present study deals with the PVA solution-based non-Newtonian Al
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-nanofluid flow along with heat transfer over wedge. The power-law model is used for this non-Newtonian nanofluid which exhibited shear-thinning behavior. The influences of PVA and nanoparticles concentrations on the characteristics of velocity and temperature profiles are examined graphically. The impacts of these parameters on wall shear stress and convective heat transfer coefficient are also studied through tabular form. During the numerical computations, the impacts of these parameters on flow index and consistency index along with other physical properties of nanofluid are also considered. In this study, we found an improvement in heat transfer and temperature profile of fluid by distribution of Al
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nanoparticles. It is also noticed that resistance between adjacent layers of moving fluid is enhanced due to these nanoparticles which leads to decline in velocity profile and increases in shear stress at wall.
Green chemistry of nanomaterials from synthesis to diverse biomedical applications is a discussion of town in the current scientific scenario. In this work, Ocimum basilicum leaves extract was ...utilized as the reducing agent in the synthesis of ZnO nanoparticles. Green synthesized ZnO NPs mediated via Ocimum basilicum extract were decorated on the reduced graphene oxide (RGO) sheet by the simple one-step method. The prepared green synthesized RGO-ZnO nanocomposites (NCs) were characterized via the X-ray diffractometer. The average crystallite size of ZnO was 25 nm which confirmed the wurtzite hexagonal structure of ZnO. The scanning Electron Microscopy technique confirmed the spherical morphology of particle size of 31 nm. Further, Fourier Transform Infrared Spectroscopy confirms the Zn-O bond stretching in the RGO-ZnO NCs. Antioxidant activity of the green synthesized Ocimum basilicum ZnO NPs and RGO-ZnO NCs were performed by DPPH scavenging activities and found the dose-dependent. RGO-ZnO effectively inhibited the α-amylase and α-glucosidase for in vitro antidiabetic activities. Moreover, RGO-ZnO NCs showed the antibacterial potential with increasing concentration against the gram-positive (Cocci) and gram-negative (E. coli) bacterial strains. In Photocatalytic activity, the ZnO NPs and RGO-ZnO NCs were utilized as the catalyst and degraded the Rh-B dye 91.4% and 96.7% under UV–visible light. Overall, RGO-ZnO NCs showed better results in antibacterial, antidiabetic activity as well as photocatalytic activity against the pure ZnO NPs. Hence, RGO-ZnO nanocomposites have demonstrated the opportunity to be an entrancing material for photocatalysis and biological studies.
The current work reports experimental outcomes about anaerobic digestion (AD) of the organic fraction of catering solid waste to produce biogas and methane yield and solidity of the entire system. ...The possibility of developing AD as an efficient technique for food waste management has also been considered. Inoculation is an established technique to enhance biogas yield through digested sludge, rumen fluid, and slurry recirculation; although this method is proven on cattle manure, however, it is not well studied on food waste. The current study investigates the use of animal intestinal waste as inoculums to enhance biogas yield of food waste. The findings are benchmarked with cattle manure employing known digester materials of carbon steel, aluminum alloy, and at anaerobic mesophilic conditions. The inoculation was varied up to 30% by mass of the substrate materials in each case. The research finds that food waste inoculation was up to 30% using carbon steel reactor under mesophilic temperature conditions (30 ± 1 °C). The food waste produced biogas at a faster rate with a higher yield compared to cattle manure in all digester materials. The biogas yield kept increasing with increasing inoculum ratio reaching optimal at 30% in the case of both food waste and cattle manure with all the digester materials.
Graphic abstract
A type of telecommunication technology called an ultra-wideband (UWB) is used to provide a typical solution for short-range wireless communication due to large bandwidth and low power consumption in ...transmission and reception. Printed monopole antennas are considered as a preferred platform for implementing this technology because of its alluring characteristics such as light weight, low cost, ease of fabrication, integration capability with other systems, etc. Therefore, a compact-sized ultra-wideband (UWB) printed monopole antenna with improved gain and efficiency is presented in this article. Computer simulation technology microwave studio (CSTMWS) software is used to build and analyze the proposed antenna design technique. This broadband printed monopole antenna contains a jug-shaped radiator fed by a coplanar waveguide (CPW) technique. The designed UWB antenna is fabricated on a low-cost FR-4 substrate with relative permittivity of 4.3, loss tangent of 0.025, and a standard height of 1.6 mm, sized at 25 mm × 22 mm × 1.6 mm, suitable for wireless communication system. The designed UWB antenna works with maximum gain (peak gain of 4.1 dB) across the whole UWB spectrum of 3–11 GHz. The results are simulated, measured, and debated in detail. Different parametric studies based on numerical simulations are involved to arrive at the optimal design through monitoring the effects of adding cuts on the performance of the proposed antennas. Therefore, these parametric studies are optimized to achieve maximum antenna bandwidth with relatively best gain. The proposed patch antenna shape is like a jug with a handle that offers greater bandwidth, good gain, higher efficiency, and compact size.
In this work, high-silica MFI zeolite adsorbent was evaluated for selective recovery of butanol from a real ABE (acetone, butanol, and ethanol) fermentation broth by batch adsorption measurements. ...The fermentation broth was produced using a hydrolyzate originating from Kraft black liquor, an internal stream in pulp mills, i.e., a low-cost substrate. The adsorbent was very selective towards butanol and butyric acid and became nearly saturated with a mixture of butanol and butyric acid with relative amounts of butanol and butyric acid depending on the pH. The presence of phenolic compounds in significant amounts in the fermentation broths, originating from the black liquor hydrolyzate, did not affect the adsorption of butanol and butyric acid.
Glaucoma is an irreversible neurodegenerative disease, where intraocular hypertension is developed due to the increased aqueous humor and blockage of the drainage system between the iris and cornea. ...As a result, the optic nerve head, which sends visual stimulus from our eyes to the brain, is damaged, causing visual field loss and ultimately blindness. Glaucoma is considered as the sneak thief of vision because it is difficult to diagnose early, and its regular screening is highly recommended to distinguish the neurological disorder. The detection of glaucoma is costly and time-consuming and not only there always remains a good possibility of human error but also this detection method is dependent upon the availability of the resources (experienced ophthalmologists and expensive instruments). In this work, an automatic glaucoma classification technique has been developed by utilizing multiple deep learning approaches. First, a new private dataset of 634 color fundus images has been collected and annotated by two eye specialists, a pediatric ophthalmologist and a glaucoma and refractive surgeon, from Bangladesh Eye Hospital, Bangladesh. Next, various deep learning models (EfficientNet, MobileNet, DenseNet, and GoogLeNet) have been used to detect glaucoma from fundus images. The model with EfficientNet-b3 architecture achieved the best results with test accuracy, F1-score, and ROC AUC of 0.9652, 0.9512, and 0.9574, respectively, for the cropped optic cup and disc fundus photographs. We also constructed a new dataset by segmenting the blood vessels from retinal fundus images employing a U-net model trained on High-Resolution Fundus Image Database. The MobileNet v3 model trained on this dataset achieved a satisfactory test accuracy of 0.8348 and an F1-score of 0.7957. This impressive result suggests that blood vessel segmentation of fundus images can be utilized as an alternative to detect glaucoma automatically.
Conventional wastewater treatment technologies are energy-intensive and environmentally un-friendly due to the use of synthetic and expensive chemicals. This study investigates the potential of ...macroalgae and coal-based biochar (control) to remove methylene blue from simulated wastewater as well as real textile wastewater. The macroalgae and coal-based biochars adsorb more than 90% of methylene blue from simulated wastewater in only 10 min on their active surface sites. The distinct feature of the current study is that macroalgae-based biochar shows high dye removal efficiency (75%) even in real textile wastewater. Macroalgae-based biochar also shows 67% dye removal efficiency for second regeneration cycle. Langmuir isotherm (> R
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= 0.954) and pseudo-second-order models (R
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= 0.999) are well fitted to describe the monolayer homogenous biosorption and process kinetics, respectively. Thermodynamic analysis indicates that methylene blue biosorption on macroalgae and coal-based biochars is a spontaneous and endothermic process following physiosorption. The maximum biosorption capacity with macroalgae-based biochar is 353.9 mg g
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at 303 K, which is approximately 27% higher than any previous biochar study on the treatment of methylene blue. It demonstrates that macroalgae-based biochars can be used as a promising alternative adsorbent to activated carbon for textile wastewater treatment.
Graphical abstract
To meet the ever-increasing energy demands, significant amount of research is carried out to find environmentally friendly and renewable energy resources. Biodiesel production through animal fats ...such as chicken fat is considered as a lucrative option due to the presence of high concentration of triglycerides and free fatty acid content. Chicken fats also contain other organic compounds, which could affect the flow properties of biodiesel. Current study is focused on developing a robust model to analyze flow behavior/model of chicken fat oil with in-depth analysis of rheological properties such as shear stress and dynamic viscosity against shear rate and time respectively. The analysis is based on experimental results as well as mathematical model and found a good agreement between the model and the results. It was found that the viscosity of a feedstock is a critical parameter for biodiesel production. If viscosity changes drastically during chemical reaction, it leads to energy losses and ultimately increases the process cost. However, chicken fat results indicate that the viscosity of chicken fat slightly decreased in the application of the shear rate. Still, the change was very small, and viscosity restored to its original value of 0.08 Pa.S, when stressed was removed. This indicate that the chicken fat oil exhibits the time-dependent non-Newtonian thixotropy fluid which leads to its potential for biodiesel production in the transport section
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