Search results for: acid solution

Authors: Spandan Sahu, Amiya Kumar Pati, Kishanjit Kumar Khatua

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Vegetation plays a major role in deciding the flow parameters in an open channel. It enhances the aesthetic view of the revetments. The major types of vegetation in river typically comprises of herbs, grasses, weeds, trees, etc. The vegetation in an open channel usually consists of aquatic plants with complete submergence, partial submergence, floating plants. The presence of vegetative plants can have both benefits and problems. The major benefits of aquatic plants are they reduce the soil erosion, which provides the water with a free surface to move on without hindrance. The obvious problems are they retard the flow of water and reduce the hydraulic capacity of the channel. The degree to which the flow parameters are affected depends upon the density of the vegetation, degree of submergence, pattern of vegetation, vegetation species. Vegetation in open channel tends to provide resistance to flow, which in turn provides a background to study the varying trends in flow parameters having vegetative growth in the channel surface. In this paper, an experiment has been conducted on a meandering channel having sinuosity of 1.33 with rigid vegetation cover to investigate the effect on flow parameters, variation of manning’s n with degree of the denseness of vegetation, vegetation pattern and submergence criteria. The measurements have been carried out in four different cross-sections two on trough portion of the meanders, two on the crest portion. In this study, the analytical solution of Shiono and knight (SKM) for lateral distributions of depth-averaged velocity and bed shear stress have been taken into account. Dimensionless eddy viscosity and bed friction have been incorporated to modify the SKM to provide more accurate results. A mathematical model has been formulated to have a comparative analysis with the results obtained from Shiono-Knight Method.

Keywords: bed friction, depth averaged velocity, eddy viscosity, SKM

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Authors: Basavaraj R. Endigeri, S. G. Sarganachari

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Steel is widely used in machine parts, structural equipment and many other applications. In many steel structural elements, holes of different shapes and orientations are made with a view to satisfy the design requirements. The presence of holes in steel elements creates stress concentration, which eventually reduce the mechanical strength of the structure. Therefore, it is of great importance to investigate the state of stress around the holes for the safety and properties design of such elements. By literature survey, it is known that till date, there is no analytical solution to reduce the stress concentration by providing auxiliary holes at a definite location and radii in a steel plate. The numerical method can be used to determine the optimum location and radii of auxiliary holes. In the present work plate with an elliptical hole, for a steel material subjected to uniaxial load is analyzed and the effect of stress concentration is graphically represented .The introduction of auxiliary holes at a optimum location and radii with its effect on stress concentration is also represented graphically. The finite element analysis package ANSYS 11.0 is used to analyse the steel plate. The analysis is carried out using a plane 42 element. Further the ANSYS optimization model is used to determine the location and radii for optimum values of auxiliary hole to reduce stress concentration. All the results for different diameter to plate width ratio are presented graphically. The results of this study are in the form of the graphs for determining the locations and diameter of optimal auxiliary holes. The graph of stress concentration v/s central hole diameter to plate width ratio. The Finite Elements results of the study indicates that the stress concentration effect of central elliptical hole in an uniaxial loaded plate can be reduced by introducing auxiliary holes on either side of the central circular hole.

Keywords: finite element method, optimization, stress concentration factor, auxiliary holes

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Authors: Ananya Govindarajan

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Tetrahymena thermophila is a single-cell, eukaryotic organism that belongs to the Protozoa Kingdom. Tetrahymena thermophila is often used in signal transduction pathway studies because of its ability to model sensory input and the effects of environmental conditions such as chemicals and temperature. The recently discovered G37 chemorepellent receptor showed increased responsiveness to all chemorepellents. Investigating the mutant G37 Tetrahymena gene in various test solutions, including ferric chloride, ferrous sulfate, hydrogen peroxide, tetrazolium blue, potassium chloride, and dithiothreitol were performed to determine the role of oxidants and reducing agents with the mutant and wild-type cells (CU427) to assess the role of the receptor. Behavioral assays and recordings processed by ImageJ indicated that ferric chloride, hydrogen peroxide, and tetrazolium blue yielded little to no chemorepellent responses from G37 cells (<20% ARs). CU427 cells were over-responsive based on the mean percent of cells (>50% ARs). Reducing agents elicited chemorepellent responses from both G37 and CU427, in addition to potassium chloride. Cell responses were classified as over-responsive (>50% ARs). Dithiothreitol yielded unexpected results as G37 (37.0% ARs) and CU427 (38.1% ARs) had relatively similar responses and were only responsive and not over-responsive to the reducing agent test chemical solution. Ultimately, this indicates that the G37 receptor is more interactive with molecules that are reducing agents or non-oxidant compounds; G37 may be unable to sense and respond to oxidants effectively, further elucidating the pathways of the G37 strain and nature of this receptor. Results also indicate that the CSF most likely contained an oxidant, like ferric chloride. This research can be further applied to neuronal influences and how specific compounds may affect human neurons individually and their excitability as the responses model action potentials and membrane potential.

Keywords: tetrahymena thermophila, signal transduction, chemosensory, oxidant, reducing agent

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Authors: Azza A. Ali, Hebatalla I. Ahmed, Asmaa Abdelaty

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Background: Manganese (Mn) is a naturally occurring element. Exposure to high levels of Mn causes neurotoxic effects and represents an environmental risk factor. Mn neurotoxicity is poorly understood but changing of AChE activity, monoamines and oxidative stress has been established. Bisphenol A (BPA) is a synthetic compound widely used in the production of polycarbonate plastics. There is considerable debate about whether its exposure represents an environmental risk. Caffeine is one of the major contributors to the dietary antioxidants which prevent oxidative damage and may reduce the risk of chronic neurodegenerative diseases. Epigallocatechin-3-gallate is another major component of green tea and has known interactions with caffeine. It also has health-promoting effects in CNS. Objective: To evaluate the potential protective effects of Caffeine and/or EGCG against Mn-induced neurotoxicity either alone or in the presence of BPA in rats. Methods: Seven groups of rats were used and received daily for 5 weeks MnCl2.4H2O (10 mg/kg, IP) except the control group which received saline, corn oil and distilled H2O. Mn was injected either alone or in combination with each of the following: BPA (50 mg/kg, PO), caffeine (10 mg/kg, PO), EGCG (5 mg/kg, IP), caffeine + EGCG and BPA +caffeine +EGCG. All rats were examined in five behavioral tests (grid, bar, swimming, open field and Y- maze tests). Biochemical changes in monoamines, caspase-3, PGE2, GSK-3B, glutamate, acetyl cholinesterase and oxidative parameters, as well as histopathological changes in the brain, were also evaluated for all groups. Results: Mn significantly increased MDA and nitrite content as well as caspase-3, GSK-3B, PGE2 and glutamate levels while significantly decreased TAC and SOD as well as cholinesterase in the striatum. It also decreased DA, NE and 5-HT levels in the striatum and frontal cortex. BPA together with Mn enhanced oxidative stress generation induced by Mn while increased monoamine content that was decreased by Mn in rat striatum. BPA abolished neuronal degeneration induced by Mn in the hippocampus but not in the substantia nigra, striatum and cerebral cortex. Behavioral examinations showed that caffeine and EGCG co-administration had more pronounced protective effect against Mn-induced neurotoxicity than each one alone. EGCG alone or in combination with caffeine prevented neuronal degeneration in the substantia nigra, striatum, hippocampus and cerebral cortex induced by Mn while caffeine alone prevented neuronal degeneration in the substantia nigra and striatum but still showed some nuclear pyknosis in cerebral cortex and hippocampus. The marked protection of caffeine and EGCG co-administration also confirmed by the significant increase in TAC, SOD, ACHE, DA, NE and 5-HT as well as the decrease in MDA, nitrite, caspase-3, PGE2, GSK-3B, the glutamic acid in the striatum. Conclusion: Neuronal degeneration induced by Mn showed some inhibition with BPA exposure despite the enhancement in oxidative stress generation. Co-administration of EGCG and caffeine can protect against neuronal degeneration induced by Mn and improve behavioral deficits associated with its neurotoxicity. The protective effect of EGCG was more pronounced than that of caffeine even with BPA co-exposure.

Keywords: manganese, bisphenol a, caffeine, epigallocatechin-3-gallate, neurotoxicity, behavioral tests, rats

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Authors: Shashank. S. Bagane, H. N. Rajendra Prasad

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Building Information Modeling (BIM) has currently developed into a potent solution. The consistent development of BIM technology in the sphere of Architecture, Engineering, and Construction (AEC) industry has enhanced the effectiveness of construction and decision making. However, aggrandized global warming and energy crisis has impacted on building energy analysis. It is now becoming an important factor to be considered in the AEC industry. Amalgamating energy analysis in the planning and design phase of a structure has become a necessity. In the current construction industry, estimating energy usage and reducing its footprint is of high priority. The construction industry is giving more prominence to sustainability alongside energy efficiency. This demand is compelling the designers, planners, and engineers to inspect the sustainable performance throughout the building's life cycle. The current study primarily focuses on energy consumption, space arrangement, and spatial geometry of a residential building. Most commonly residential structures in India are constructed considering Vastu Shastra. Vastu designs are intended to integrate architecture with nature and utilizing geometric patterns, symmetry, and directional alignments. In the current study, a residential brick masonry structure is considered for BIM analysis, Architectural model of the structure will be created using Revit software, later the orientation and spatial arrangement will be finalized based on Vastu principles. Furthermore, the structure will be investigated for the impact of building orientation and spatial arrangements on energy using Green Building Studio software. Based on the BIM analysis of the structure, energy consumption of subsequent building orientations will be understood. A well-orientated building having good spatial arrangement can save a considerable amount of energy throughout its life cycle and reduces the need for heating and lighting which will prove to diminish energy usage and improve the energy efficiency of the residential building.

Keywords: building information modeling, energy impact, spatial geometry, vastu

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Authors: Franziska Mais, Till Gramberg

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The paper presents the development of a sustainable business model for a platform-based application tailored for sawing companies in small and medium-sized enterprises (SMEs). The focus is on the integration of sustainability principles into the design of the business model to ensure a technologically advanced, legally sound, and economically efficient solution. Easy2IoT is a research project that aims to enable companies in the prefabrication sheet metal and sheet metal processing industry to enter the Industrial Internet of Things (IIoT) with a low-threshold and cost-effective approach. The methodological approach of Easy2IoT includes an in-depth requirements analysis and customer interviews with stakeholders along the value chain. Based on these insights, actions, requirements, and potential solutions for smart services are derived. The structuring of the business ecosystem within the application plays a central role, whereby the roles of the partners, the management of the IT infrastructure and services, as well as the design of a sustainable operator model are considered. The business model is developed using the value proposition canvas, whereby a detailed analysis of the requirements for the business model is carried out, taking sustainability into account. This includes coordination with the business model patterns, according to Gassmann, and integration into a business model canvas for the Easy2IoT product. Potential obstacles and problems are identified and evaluated in order to formulate a comprehensive and sustainable business model. In addition, sustainable payment models and distribution channels are developed. In summary, the article offers a well-founded insight into the systematic development of a sustainable business model for platform-based applications in SME sawmills, with a particular focus on the synergy of ecological responsibility and economic efficiency.

Keywords: business model, sustainable business model, IIoT, IIoT-platform, industrie 4.0, big data

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Authors: Latha Krishnan, Andrew Cobley

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Epoxy resin is most widely used as matrices for composites of aerospace, automotive and electronic applications due to its outstanding mechanical properties. These properties are chiefly predetermined by the chemical structure of the prepolymer and type of hardener but can also be varied by the processing conditions such as prepolymer and hardener mixing, degassing and curing conditions. In this research, the effect of degassing on the curing behaviour and the void occurrence is experimentally evaluated for epoxy /anhydride resin system. The epoxy prepolymer was mixed with an anhydride hardener and accelerator in an appropriate quantity. In order to investigate the effect of degassing on the curing behaviour and void content of the resin, the uncured resin samples were prepared using three different methods: 1) no degassing 2) degassing on prepolymer and 3) degassing on mixed solution of prepolymer and hardener with an accelerator. The uncured resins were tested in differential scanning calorimeter (DSC) to observe the changes in curing behaviour of the above three resin samples by analysing factors such as gel temperature, peak cure temperature and heat of reaction/heat flow in curing. Additionally, the completely cured samples were tested in DSC to identify the changes in the glass transition temperature (Tg) between the three samples. In order to evaluate the effect of degassing on the void content and morphology changes in the cured epoxy resin, the fractured surfaces of cured epoxy resin were examined under the scanning electron microscope (SEM). In addition, the amount of void, void geometry and void fraction were also investigated using an optical microscope and image J software (image analysis software). It was found that degassing at different stages of resin mixing had significant effects on properties such as glass transition temperature, the void content and void size of the epoxy/anhydride resin system. For example, degassing (vacuum applied on the mixed resin) has shown higher glass transition temperature (Tg) with lower void content.

Keywords: anhydride epoxy, curing behaviour, degassing, void occurrence

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Authors: Gayatri Mahajan

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Modern Construction Technology (CT) includes a broad range of advanced techniques and practices that bound the recent developments in material technology, design methods, quantity surveying, facility management, services, structural analysis and design, and other management education. Adoption of recent digital transformation technology is the need of today to speed up the business and is also the basis of construction improvement. Incorporating and practicing the technologies such as cloud-based communication and collaboration solution, Mobile Apps and 5G,3D printing, BIM and Digital Twins, CAD / CAM, AR/ VR, Big Data, IoT, Wearables, Blockchain, Modular Construction, Offsite Manifesting, Prefabrication, Robotic, Drones and GPS controlled equipment expedite the progress in the Construction industry (CI). Resources used are journaled research articles, web/net surfing, books, thesis, reports/surveys, magazines, etc. The outline of the research organization for this study is framed at four distinct levels in context to conceptualization, resources, innovative and emerging trends in CI, and better methods for completion of the construction projects. The present study conducted during 2020-2022 reveals that implementing these technologies improves the level of standards, planning, security, well-being, sustainability, and economics too. Application uses, benefits, impact, advantages/disadvantages, limitations and challenges, and policies are dealt with to provide information to architects and builders for smooth completion of the project. Results explain that construction technology trends vary from 4 to 15 for CI, and eventually, it reaches 27 for Civil Engineering (CE). The perspective of the most recent innovations, trends, tools, challenges, and solutions is highly embraced in the field of construction. The incorporation of the above said technologies in the pandemic Covid -19 and post-pandemic might lead to a focus on finding out effective ways to adopt new-age technologies for CI.

Keywords: BIM, drones, GPS, mobile apps, 5G, modular construction, robotics, 3D printing

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Authors: Ayman H. Amer Eissa, Abdul Rahman O. Alghannam

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The agricultural crop residuals are considered one of the most important problems faced by the environmental life and farmers in the world. A study was carried out to evaluate the physical characteristics of chopped date palm stalks (fronds and leaflets). These properties are necessary to apply normal design procedures such as pneumatic conveying, fluidization, drying, and combustion. The mechanical treatment by cutting, crushing or chopping and briquetting processes are the primary step and the suitable solution for solving this problem and recycling these residuals to be transformed into useful products. So the aim of the present work to get a high quality for agriculture residues such as date palm stalks (fronds), date palm leaflets briquettes. The results obtained from measuring the mechanical properties (average shear and compressive strength) for date palm stalks at different moisture content (12.63, 33.21 and 60.54%) was (6.4, 4.7 and 3.21MPa) and (3.8, 3.18 and 2.86MPa) respectively. The modulus of elasticity and toughness were evaluated as a function of moisture content. As the moisture content of the stalk regions increased the modulus of elasticity and toughness decreased indicating a reduction in the brittleness of the stalk regions. Chopped date palm stalks (palm fronds), date palm leaflets having moisture content of 8, 10 and 12% and 8, 10 and 12.8% w.b. were dandified into briquettes without binder and with binder (urea-formaldehyde) using a screw press machine. Quality properties for briquettes were durability, compression ratio hardness, bulk density, compression ratio, resiliency, water resistance and gases emission. The optimum quality properties found for briquettes at 8 % moisture content and without binder. Where the highest compression stress and durability were 8.95, 10.39 MPa and 97.06 %, 93.64 % for date palm stalks (palm fronds), date palm leaflets briquettes, respectively. The CO and CO2 emissions for date palm stalks (fronds), date palm leaflets briquettes were less than these for loose residuals.

Keywords: residues, date palm stalks, chopper, briquetting, quality properties

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Authors: Sami Ayad, Mengshan Lee

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The Sustainable Development Goals (SDGs) were designed to be the best possible blueprint to achieve peace, prosperity, and overall, a better and more sustainable future for the Earth and all its people, and such a blueprint is needed more than ever. The SDGs face many hurdles that will prevent them from becoming a reality, one of such hurdles, arguably, is the chemical pollution and unintended chemical impacts generated through the production of various goods and resources that we consume. Chemical Alternatives Assessment has proven to be a viable solution for chemical pollution management in terms of filtering out hazardous chemicals for a greener alternative. However, the current substitution practice lacks crucial quantitative datasets (exposures and life cycle impacts) to ensure no unintended trade-offs occur in the substitution process. A Chemical Life Cycle Alternative Assessment (CLiCAA) framework is proposed as a reliable and replicable alternative to Life Cycle Based Alternative Assessment (LCAA) as it integrates chemical molecular structure analysis and Chemical Life Cycle Collaborative (CLiCC) web-based tool to fill in data gaps that the former frameworks suffer from. The CLiCAA framework consists of a four filtering layers, the first two being mandatory, with the final two being optional assessment and data extrapolation steps. Each layer includes relevant impact categories of each chemical, ranging from human to environmental impacts, that will be assessed and aggregated into unique scores for overall comparable results, with little to no data. A feasibility study will demonstrate the efficiency and accuracy of CLiCAA whilst bridging both cancer potency and exposure limit data, hoping to provide the necessary categorical impact information for every firm possible, especially those disadvantaged in terms of research and resource management.

Keywords: chemical alternative assessment, LCA, LCAA, CLiCC, CLiCAA, chemical substitution framework, cancer potency data, chemical molecular structure analysis

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Authors: Amine Alaoui Sanae, Tagjdid Reda, Loutfi Chafiqa, Melloul Merouane, Laloui Aziz, Touil Nadia, El Fahim, E. Mostafa

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Background: Rotavirus group A (RVA) strains with G8P[14] specificities are usually detected in calves and goats. However, these strains have been reported globally in humans and have often been characterized as originating from zoonotic transmissions, particularly in area where ruminants and humans live side-by-side. Whether human P[14] genotypes are two-way and can be transmitted to animal species remains to be established. Here we describe VP4 deduced amino-acid relationships of three Moroccan P[14] genotypes originating from different species and the receptiveness of an alpine goat to a human G8P[14] through an experimental infection. Material/methods: the human MA31 RVA strain was originally identified in a four years old girl presenting an acute gastroenteritis hospitalized at the pediatric care unit in Rabat Hospital in 2011. The virus was isolated and propagated in MA104 cells in the presence of trypsin. Ch_10S and 8045_S animal RVA strains were identified in fecal samples of a 2-week-old native goat and 3-week-old calf with diarrhea in 2011 in Bouaarfa and My Bousselham respectively. Genomic RNAs of all strains were subjected to a two-step RT-PCR and sequenced using the consensus primers VP4. The phylogenetic tree for MA31, Ch_10S and 8045_S VP4 and a set of published P[14] genotypes was constructed using MEGA6 software. The receptivity of MA31 strain by an eight month-old alpine goat was assayed. The animal was orally and intraperitonally inoculated with a dose of 8.5 TCID50 of virus stock at passage level 3. The shedding of the virus was tested by a real time RT-PCR assay. Results: The phylogenetic tree showed that the three Moroccan strains MA31, Ch_10S and 8045_S VP4 were highly related to each other (100% similar at the nucleotide level). They were clustered together with the B10925, Sp813, PA77 and P169 strains isolated in Belgium, Spain and Italy respectively. The Belgian strain B10925 was the most closely related to the Moroccan strains. In contrast, the 8045_S and Ch_10S strains were clustered distantly from the Tunisian calf strain B137 and the goat strain cap455 isolated in South Africa respectively. The human MA31 RVA strain was able to induce bloody diarrhea at 2 days post infection (dpi) in the alpine goat kid. RVA virus shedding started by 2 dpi (Ct value of 28) and continued until 5 dpi (Ct value of 25) with a concomitant elevation in the body temperature. Conclusions: Our study while limited to one animal, is the first study proving experimentally that a human P[14] genotype causes diarrhea and virus shedding in the goat. This result reinforce the potential role of inter- species transmission in generating novel and rare rotavirus strains such G8P[14] which infect humans.

Keywords: interspecies transmission, rotavirus, goat, human

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Authors: Sofie Verstraete, Stijn Debruyne, Frederik Desplentere

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Considering environmental issues, the interest to apply sustainable materials in industry increases. Specifically for composites, there is an emerging need for suitable materials and bonding techniques. As an alternative to traditional composites, short bio-fiber (cellulose-based flax) reinforced Polylactic Acid (PLA) is gaining popularity. However, these thermoplastic based composites show issues in adhesive bonding. This research focusses on analyzing the effects of the fibers near the bonding interphase. The research applies injection molded plate structures. A first important parameter concerns the fiber volume fraction, which directly affects adhesion characteristics of the surface. This parameter is varied between 0 (pure PLA) and 30%. Next to fiber volume fraction, the orientation of fibers near the bonding surface governs the adhesion characteristics of the injection molded parts. This parameter is not directly controlled in this work, but its effects are analyzed. Surface roughness also greatly determines surface wettability, thus adhesion. Therefore, this research work considers three different roughness conditions. Different mechanical treatments yield values up to 0.5 mm. In this preliminary research, only one adhesive type is considered. This is a two-part epoxy which is cured at 23 °C for 48 hours. In order to assure a dedicated parametric study, simple and reproduceable adhesive bonds are manufactured. Both single lap (substrate width 25 mm, thickness 3 mm, overlap length 10 mm) and double lap tests are considered since these are well documented and quite straightforward to conduct. These tests are conducted for the different substrate and surface conditions. Dog bone tensile testing is applied to retrieve the stiffness and strength characteristics of the substrates (with different fiber volume fractions). Numerical modelling (non-linear FEA) relates the effects of the considered parameters on the stiffness and strength of the different joints, obtained through the abovementioned tests. Ongoing work deals with developing dedicated numerical models, incorporating the different considered adhesion parameters. Although this work is the start of an extensive research project on the bonding characteristics of thermoplastic bio-fiber reinforced composites, some interesting results are already prominent. Firstly, a clear correlation between the surface roughness and the wettability of the substrates is observed. Given the adhesive type (and viscosity), it is noticed that an increase in surface energy is proportional to the surface roughness, to some extent. This becomes more pronounced when fiber volume fraction increases. Secondly, ultimate bond strength (single lap) also increases with increasing fiber volume fraction. On a macroscopic level, this confirms the positive effect of fibers near the adhesive bond line.

Keywords: adhesive bonding, bio-fiber reinforced composite, flax fibers, lap joint

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Authors: Sharon Waichman, Shahaf Froim, Ido Zukerman, Shmuel Barzilai, Shmual Hayun, Avi Raveh

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Boron carbide is a ceramic material with superior properties such as high chemical and thermal stability, high hardness and high wear resistance. Moreover, it has a big cross section for neutron absorption and therefore can be employed in nuclear based applications. However, an efficient attachment of boron carbide to a metal such as aluminum can be very challenging, mainly because of the formation of aluminum-carbon bonds that are unstable in humid environment, the affinity of oxygen to the metal and the different thermal expansion coefficients of the two materials that may cause internal stresses and a subsequent failure of the bond. Here, we aimed to achieving a strong and a durable attachment between the boron carbide coating and the aluminum substrate. For this purpose, we applied Ti as a thin intermediate layer that provides a gradual change in the thermal expansion coefficients of the configured layers. This layer is continuous and therefore prevents the formation of aluminum-carbon bonds. Boron carbide coatings with a thickness of 1-5 µm were deposited on the aluminum substrate by pulse-DC magnetron sputtering. Prior to the deposition of the boron carbide layer, the surface was pretreated by energetic ion plasma followed by deposition of the Ti intermediate adhesive layer in a continuous process. The properties of the Ti intermediate layer were adjusted by the bias applied to the substrate. The boron carbide/aluminum bond was evaluated by various methods and complementary techniques, such as SEM/EDS, XRD, XPS, FTIR spectroscopy and Glow Discharge Spectroscopy (GDS), in order to explore the structure, composition and the properties of the layers and to study the adherence mechanism of the boron carbide/aluminum contact. Based on the interfacial bond characteristics, we propose a desirable solution for improved adhesion of boron carbide to aluminum using a highly efficient intermediate adhesive layer.

Keywords: adhesion, boron carbide coatings, ceramic/metal bond, intermediate layer, pulsed-DC magnetron sputtering

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Authors: Rabindranath Jana, Plabani Basu, Keka Rana

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Nucleating agents are widely used to modify the properties of various polymers. The rate of crystallization and the size of the crystals have a strong impact on mechanical and optical properties of a polymer. The addition of nucleating agents to the semi-crystalline polymers provides a surface on which the crystal growth can start easily. As a consequence, fast crystal formation will result in many small crystal domains so that the cycle times for injection molding may be reduced. Moreover, the mechanical properties e.g., modulus, tensile strength, heat distortion temperature and hardness may increase. In the present work, multi-walled carbon nanotubes (MWNTs) as nucleating agents for the crystallization of poly (e-caprolactone)diol (PCL). Thus nanocomposites of PCL filled with MWNTs were prepared by solution blending. Differential scanning calorimetry (DSC) tests were carried out to study the effect of CNTs on on-isothermal crystallization of PCL. The polarizing optical microscopy (POM), and wide-angle X-ray diffraction (WAXD) were used to study the morphology and crystal structure of PCL and its nanocomposites. It is found that MWNTs act as effective nucleating agents that significantly shorten the induction period of crystallization and however, decrease the crystallization rate of PCL, exhibiting a remarkable decrease in the Avrami exponent n, surface folding energy σe and crystallization activation energy ΔE. The carbon-based fillers act as templates for hard block chains of PCL to form an ordered structure on the surface of nanoparticles during the induction period, bringing about some increase in equilibrium temperature. The melting process of PCL and its nanocomposites are also studied; the nanocomposites exhibit two melting peaks at higher crystallization temperature which mainly refer to the melting of the crystals with different crystal sizes however, PCL shows only one melting temperature.

Keywords: poly(e-caprolactone)diol, multiwalled carbon nanotubes, composite materials, nonisothermal crystallization, crystal structure, nucleation

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Authors: Akram Balaswad, Muhammad Farzik Ijaz, Shahid Parves

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In the face of growing global environmental concerns and the urgent need for sustainable material methods, the use of bio-composites has emerged as a promising solution. Bio-composites, which integrate natural fibers or agricultural wastes, offer several advantages, such as easy disposal, fewer health hazards, and reduced energy consumption during manufacturing. They also contribute to weight reduction in products, leading to lower carbon emissions and energy savings. This study focuses on the development and characterization of bio-composites using recycled aluminum, eggshell carbonized powder (ECP), and date seed powder (DSP) for engineering applications. The research will investigate the mechanical and corrosion characteristics of the bio-composites and assess their feasibility for practical use in various engineering fields. Recycled aluminum and agro-waste materials are utilized to enhance sustainability, reduce environmental impact, and promote a circular economy. The study will highlight the potential of these eco-friendly materials in improving mechanical and corrosion properties, making them suitable for a wide range of engineering applications. The fabrication process will involve sourcing materials from local sources, cleaning, processing, and fabricating composites using a stir casting technique. Statistical analysis using ANNOVA will be done to compare the amount of variation of organic reinforcement (ECP / DSP) between groups with the amount of variation within groups Characterization methods include tensile testing, Vickers macro-hardness testing, SEM analysis, and corrosion testing. This research will contribute to the development of sustainable engineering materials and support the global and local efforts towards environmentally conscious practices.

Keywords: bio-composites, sustainability, recycled aluminum, eggshell carbonized powder (ECP), date seed powder (DSP)

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Authors: Mario Alejandro Grisales, M. Daniela Chimá, Gilberto Bejarano Gaitán

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High entropy alloys (HEA) and nitride (HEN) are currently very attractive to the automotive, aerospace, metalworking and materials forming manufacturing industry, among others, for exhibiting higher mechanical properties, wear resistance, and thermal stability than binary and ternary alloys. In this work medium-entropy coatings of TiTaZrNb and the nitrides of (TiTaZrNb)Nx were synthesized on to AISI 420 and M2 steel samples by the direct current magnetron sputtering technique. The influence of the bias voltage supplied to the substrate on the microstructure, chemical- and phase composition of the matrix coating was evaluated, and the effect of nitrogen flow on the microstructural, mechanical and tribological properties of the corresponding nitrides was studied. A change in the crystalline structure from BCC for TiTaZrNb coatings to FCC for (TiTaZrNb)Nx was observed, that is associated with the incorporation of nitrogen into the matrix and the consequent formation of a solid solution of (TiTaZrNb)Nx. An increase in hardness and residual stresses was observed with increasing bias voltage for TiTaZrNb, reaching 12.8 GPa for the coating deposited with a bias of -130V. In the case of (TiTaZrNb)Nx nitride, a greater hardness of 23 GPa is achieved for the coating deposited with a N2 flow of 12 sccm, which slightly drops to 21.7 GPa for that deposited with N2 flow of 15 sccm. The slight reduction in hardness could be associated with the precipitation of the TiN and ZrN phases that are formed at higher nitrogen flows. The specific wear rate of the deposited coatings ranged between 0.5xexp13 and 0.6xexp13 N/m2. The steel substrate exhibited an average hardness of 2.0 GPa and a specific wear rate of 203.2exp13 N/m2. Both the hardness and the specific wear rate of the synthesized nitride coatings were higher than that of the steel substrate, showing a protective effect of the steel against wear.

Keywords: medium entropy coatings, hard coatings, magnetron sputtering, tribology, wear resistance

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Authors: Merve Uzuner Sahin, Kumru D. Atalay, Berna Dengiz

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In today’s competitive market, there are many alternative products that can be used in similar manner and purpose. Therefore, the utility of the product is an important issue for the preferability of the brand. This utility could be measured in terms of its functionality, durability, reliability. These all are affected by the system capabilities. Reliability is an important system design criteria for the manufacturers to be able to have high availability. Availability is the probability that a system (or a component) is operating properly to its function at a specific point in time or a specific period of times. System availability provides valuable input to estimate the production rate for the company to realize the production plan. When considering only the corrective maintenance downtime of the system, mean time between failure (MTBF) and mean time to repair (MTTR) are used to obtain system availability. Also, the MTBF and MTTR values are important measures to improve system performance by adopting suitable maintenance strategies for reliability engineers and practitioners working in a system. Failure and repair time probability distributions of each component in the system should be known for the conventional availability analysis. However, generally, companies do not have statistics or quality control departments to store such a large amount of data. Real events or situations are defined deterministically instead of using stochastic data for the complete description of real systems. A fuzzy set is an alternative theory which is used to analyze the uncertainty and vagueness in real systems. The aim of this study is to present a novel approach to compute system availability using representation of MTBF and MTTR in fuzzy numbers. Based on the experience in the system, it is decided to choose 3 different spread of MTBF and MTTR such as 15%, 20% and 25% to obtain lower and upper limits of the fuzzy numbers. To the best of our knowledge, the proposed method is the first application that is used fuzzy MTBF and fuzzy MTTR for fuzzy system availability estimation. This method is easy to apply in any repairable production system by practitioners working in industry. It is provided that the reliability engineers/managers/practitioners could analyze the system performance in a more consistent and logical manner based on fuzzy availability. This paper presents a real case study of a repairable multi-stage production line in lead-acid battery production factory in Turkey. The following is focusing on the considered wet-charging battery process which has a higher production level than the other types of battery. In this system, system components could exist only in two states, working or failed, and it is assumed that when a component in the system fails, it becomes as good as new after repair. Instead of classical methods, using fuzzy set theory and obtaining intervals for these measures would be very useful for system managers, practitioners to analyze system qualifications to find better results for their working conditions. Thus, much more detailed information about system characteristics is obtained.

Keywords: availability analysis, battery production system, fuzzy sets, triangular fuzzy numbers (TFNs)

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Authors: Merouane Salhi, Mohamed Roudane, Abdelkader Kirad

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In this work, we present a new form of characteristics method, which is a technique for solving partial differential equations. Typically, it applies to first-order equations; the aim of this method is to reduce a partial differential equation to a family of ordinary differential equations along which the solution can be integrated from some initial data. This latter developed under the real gas theory, because when the thermal and the caloric imperfections of a gas increases, the specific heat and their ratio do not remain constant anymore and start to vary with the gas parameters. The gas doesn’t stay perfect. Its state equation change and it becomes for a real gas. The presented equations of the characteristics remain valid whatever area or field of study. Here we need have inserted the developed Prandtl Meyer function in the mathematical system to find a new model when the effect of stagnation pressure is taken into account. In this case, the effects of molecular size and intermolecular attraction forces intervene to correct the state equation, the thermodynamic parameters and the value of Prandtl Meyer function. However, with the assumptions that Berthelot’s state equation accounts for molecular size and intermolecular force effects, expressions are developed for analyzing the supersonic flow for thermally and calorically imperfect gas. The supersonic parameters depend directly on the stagnation parameters of the combustion chamber. The resolution has been made by the finite differences method using the corrector predictor algorithm. As results, the developed mathematical model used to design 2D minimum length nozzles under effect of the stagnation parameters of fluid flow. A comparison for air with the perfect gas PG and high temperature models on the one hand and our results by the real gas theory on the other of nozzles shapes and characteristics are made.

Keywords: numerical methods, nozzles design, real gas, stagnation parameters, supersonic expansion, the characteristics method

Procedia PDF Downloads 245

Authors: Abdullah Kattan, Khalid Alzahrani, Saud Alsaleh, Loui Ezzat, Khalid Murad, Bader Alghamdi

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Background and Significance: Patients are often bothered by the excess skin laxity and redundancy that they are left with after losing weight. Body-contouring surgery offers a solution to this problem; however, there is scarce literature on the psychological and social effects of these surgeries. This study was conducted to assess the psychosocial impact of body-contouring surgery on patients after weight loss. Methodology: In this cross-sectional study, a specifically designed questionnaire was administered to forty three patients whom have undergone body-contouring surgery. All included patients had lost no less than 20 Kg before body-contouring surgery, and were interviewed at least 6 months after surgery. The twenty-question interviewer based questionnaire was used to assess the psychosocial status of the patients before and after undergoing body-contouring surgery. The questionnaire assessed the quality of life (social life, job performance and sexual activity), presence of symptoms of depression and overall satisfaction. Data was analyzed as paired variables in SPSS using McNemar’s test. Results: Among the 43 participants, 19 (44.2%) have undergone mammoplasty, 12 (27.9%) have undergone abdominoplasty and the remainder of the patients have undergone other various procedures including brachioplasty, thigh lifts and nick liposuction. The mean age of patients was 34 +/- 10, the sample included 24 (55.8%) females and 19 (44.2%) males. The patients’ quality of life significantly improved in the following areas; social life (P<0.001), job performance (P<0.002) and sexual activity (P<0.001). Moreover, 17 (39.5%) patients suffered symptoms of depression before body-contouring surgery; however, only 1 (2.3%) patient suffered symptoms of depression after surgery. Overall satisfaction rate was found to be 62.8%; with mammoplasty being the highest satisfaction rate procedure (66.6 %). Conclusion: Body-contouring surgery after weight loss has shown to improve the psychological and social aspects in patients. These findings have been found to be consistent with the majority of relevant published studies, further increasing reliability of our study.

Keywords: abdominoplasty, body-contouring, mammoplasty, psychosocial

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Authors: Olympia Nisiforou

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The cultural heritage of each country represents a unique and irreplaceable witness of the past. Nevertheless, on many occasions, such heritage is extremely vulnerable to natural disasters and reckless behaviors. Even if such exhibits are now located in Museums, they still receive insufficient protection due to improper environmental conditions. These external changes can negatively affect the conditions of the exhibits and contribute to inefficient maintenance in time. Hence, it is imperative to develop an innovative, low-cost system, to monitor indoor air quality systematically, since conventional methods are quite expensive and time-consuming. The present study gives an insight into the indoor air quality of the National Byzantine Museum of Cyprus. In particular, systematic measurements of particulate matter, bio-aerosols, the concentration of targeted chemical pollutants (including Volatile organic compounds (VOCs), temperature, relative humidity, and lighting conditions as well as microbial counts have been performed using conventional techniques. Measurements showed that most of the monitored physiochemical parameters did not vary significantly within the various sampling locations. Seasonal fluctuations of ammonia were observed, showing higher concentrations in the summer and lower in winter. It was found that the outdoor environment does not significantly affect indoor air quality in terms of VOC and Nitrogen oxides (NOX). A cutting-edge portable Gas Chromatography-Mass Spectrometry (GC-MS) system (TORION T-9) was used to identify and measure the concentrations of specific Volatile and Semi-volatile Organic Compounds. A large number of different VOCs and SVOCs found such as Benzene, Toluene, Xylene, Ethanol, Hexadecane, and Acetic acid, as well as some more complex compounds such as 3-ethyl-2,4-dimethyl-Isopropyl alcohol, 4,4'-biphenylene-bis-(3-aminobenzoate) and trifluoro-2,2-dimethylpropyl ester. Apart from the permanent indoor/outdoor sources (i.e., wooden frames, painted exhibits, carpets, ventilation system and outdoor air) of the above organic compounds, the concentration of some of them within the areas of the museum were found to increase when large groups of visitors were simultaneously present at a specific place within the museum. The high presence of Particulate Matter (PM), fungi and bacteria were found in the museum’s areas where carpets were present but low colonial counts were found in rooms where artworks are exhibited. Measurements mentioned above were used to validate an innovative low-cost air-quality monitoring system that has been developed within the present work. The developed system is able to monitor the average concentrations (on a bidaily basis) of several pollutants and presents several innovative features, including the prompt alerting in case of increased average concentrations of monitored pollutants, i.e., exceeding the limit values defined by the user.

Keywords: exibitions, indoor air quality , VOCs, pollution

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Authors: Drago Diaz Aleman, Jose Luis Saorin Perez, Cecile Meier, Itahisa Perez Conesa, Jorge De La Torre Cantero

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Traditional manufacturing techniques used in artistic contexts compete with highly productive and efficient industrial procedures. The craft techniques and associated business models tend to disappear under the pressure of the appearance of mass-produced products that compete in all niche markets, including those traditionally reserved for the work of art. The surplus value derived from the prestige of the author, the exclusivity of the product or the mastery of the artist, do not seem to be sufficient reasons to preserve this productive model. In the last years, the adoption of open source digital manufacturing technologies in small art workshops can favor their permanence by assuming great advantages such as easy accessibility, low cost, and free modification, adapting to specific needs of each workshop. It is possible to use pieces modeled by computer and made with FDM (Fused Deposition Modeling) 3D printers that use PLA (polylactic acid) in the procedures of artistic casting. Models printed by PLA are limited to approximate minimum sizes of 3 cm, and optimal layer height resolution is 0.1 mm. Due to these limitations, it is not the most suitable technology for artistic casting processes of smaller pieces. An alternative to solve size limitation, are printers from the type (SLS) "selective sintering by laser". And other possibility is a laser hardens, by layers, metal powder and called DMLS (Direct Metal Laser Sintering). However, due to its high cost, it is a technology that is difficult to introduce in small artistic foundries. The low-cost DLP (Digital Light Processing) type printers can offer high resolutions for a reasonable cost (around 0.02 mm on the Z axis and 0.04 mm on the X and Y axes), and can print models with castable resins that allow the subsequent direct artistic casting in precious metals or their adaptation to processes such as electroforming. In this work, the design of a DLP 3D printer is detailed, using backlit LCD screens with ultraviolet light. Its development is totally "open source" and is proposed as a kit made up of electronic components, based on Arduino and easy to access mechanical components in the market. The CAD files of its components can be manufactured in low-cost FDM 3D printers. The result is less than 500 Euros, high resolution and open-design with free access that allows not only its manufacture but also its improvement. In future works, we intend to carry out different comparative analyzes, which allow us to accurately estimate the print quality, as well as the real cost of the artistic works made with it.

Keywords: traditional artistic techniques, DLP 3D printer, artistic casting, electroforming

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Authors: Samuel Kehinde Okunade, Daniel Sunday Tolorunshagba

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Globally women are classified to be part of the vulnerable group in any environment. In a conflict-ridden environment, women being vulnerable often suffer the consequences as it relates to security and access to basic social services such as medical care. This is the situation in border communities in Nigeria where cross-border crimes are on the rife, thus, putting women at a disadvantaged position and, eventually, victims of such inimical activities. Border communities in the Saki/Iseyin area of Oyo state are a case in point where the lives of inhabitants are daily threatened most, especially women. In light of the above, this article examined the security situation of the Saki/Iseyin area of Oyo State with a view to ascertaining its status in terms of safety of lives and property. This paper also explored the experiences of women in the border communities within the area as it relates to their safety, the safety of their children, access to good health facilities in their immediate environment, and above all, how they have been able to cope or manage the situation. The qualitative research model was adopted utilizing a phenomenological case study approach. A Focused Group Discussion was conducted with 10 pregnant women and 10 mothers in Okerete and Abugudu communities while a Key Informant Interview was conducted with the women leaders in both communities of the Saki/Iseyin border area of Oyo State. The findings of the study revealed the poor state of basic infrastructure. So bad to a point that inhabitants of these communities no longer see themselves as Nigerians because they have been neglected by the government for too long. The only solution is for the government to embark on developmental projects within these communities so that they can live a good life just as those in the cities do. More importantly, this will increase the loyalty of these communities to the Nigeria state by defending and resisting all forms of cross-border criminal activities that go on along the porous borders.

Keywords: security, women, Saki/Iseyin border area, cross-border criminalities, basic infrastructure

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Authors: A. Alzeyadi, E. Loffill, R. Alkhaddar

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Continuous upflow filters can combine the nutrient (nitrogen and phosphate) and suspended solid removal in one unit process. The contaminant removal could be achieved chemically or biologically; in both processes the filter removal efficiency depends on the interaction between the packed filter media and the influent. In this paper a residence time distribution (RTD) study was carried out to understand and compare the transfer behaviour of contaminants through a selected filter media packed in a laboratory-scale continuous up flow filter; the selected filter media are limestone and white dolomite. The experimental work was conducted by injecting a tracer (red drain dye tracer –RDD) into the filtration system and then measuring the tracer concentration at the outflow as a function of time; the tracer injection was applied at hydraulic loading rates (HLRs) (3.8 to 15.2 m h-1). The results were analysed according to the cumulative distribution function F(t) to estimate the residence time of the tracer molecules inside the filter media. The mean residence time (MRT) and variance σ2 are two moments of RTD that were calculated to compare the RTD characteristics of limestone with white dolomite. The results showed that the exit-age distribution of the tracer looks better at HLRs (3.8 to 7.6 m h-1) and (3.8 m h-1) for limestone and white dolomite respectively. At these HLRs the cumulative distribution function F(t) revealed that the residence time of the tracer inside the limestone was longer than in the white dolomite; whereas all the tracer took 8 minutes to leave the white dolomite at 3.8 m h-1. On the other hand, the same amount of the tracer took 10 minutes to leave the limestone at the same HLR. In conclusion, the determination of the optimal level of hydraulic loading rate, which achieved the better influent distribution over the filtration system, helps to identify the applicability of the material as filter media. Further work will be applied to examine the efficiency of the limestone and white dolomite for phosphate removal by pumping a phosphate solution into the filter at HLRs (3.8 to 7.6 m h-1).

Keywords: filter media, hydraulic loading rate, residence time distribution, tracer

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Authors: Thomas Wetere

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Background: The coronavirus disease 2019 (COVID-19) pandemic (COVID-19) virus infection is a severe infectious disease with the highly transmissible variant, which become the global public health treat now. It has taken the life of more than 4 million people so far. What makes the disease the worst of all is no specific effective treatment available, its dynamics is not much researched and understood. Methodology: To end the global COVID-19 pandemic, implementation of multiple population-wide strategies, including vaccination, environmental factors, Government action, testing, and contact tracing, is required. In this article, a new mathematical model incorporating both temperature and government action to study the dynamics of the COVID-19 pandemic has been developed and comprehensively analysed. The model considers eight stages of infection: susceptible (S), infected Asymptomatic and Undetected(IAU ), infected Asymptomatic and detected(IAD), infected symptomatic and Undetected(ISU ), infected Symptomatic and detected(ISD), Hospitalized or threatened(H), Recovered(R) and Died(D). Results: The existence as well as non-negativity of the solution to the model is also verified, and the basic reproduction number is calculated. Besides, stability conditions are also checked, and finally, simulation results are compared with real data. The results demonstrates that effective government action will need to be combined with vaccination to end the ongoing COVID-19 pandemic. Conclusion: Vaccination and Government action are highly the crucial measures to control the COVID-19 pandemic. Besides, as the cost of vaccination might be high, we recommend an optimal control to reduce the cost and number of infected individuals. Moreover, in order to prevent COVID-19 pandemic, through the analysis of the model, the government must strictly manage the policy on COVID-19 and carry it out. This, in turn, helps for health campaigning and raising health literacy which plays a role to control the quick spread of the disease. We finally strongly believe that our study will play its own role in the current effort of controlling the pandemic.

Keywords: modeling, COVID-19, MCMC, stability

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Authors: Farzam Fatolazadeh, Kalifa Goita, Mehdi Eshagh, Shusen Wang

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The Gravity Recovery and Climate Experiment (GRACE) is a satellite mission with twin satellites for the precise determination of spatial and temporal variations in the Earth’s gravity field. The products of this mission are monthly global gravity models containing the spherical harmonic coefficients and their errors. These GRACE models can be used for estimating terrestrial water storage (TWS) variations across the globe at large scales, thereby offering an opportunity for surface and groundwater storage (GWS) assessments. Yet, the ability of GRACE to monitor changes at smaller scales is too limited for local water management authorities. This is largely due to the low spatial and temporal resolutions of its models (~200,000 km2 and one month, respectively). High-resolution GRACE data products would substantially enrich the information that is needed by local-scale decision-makers while offering the data for the regions that lack adequate in situ monitoring networks, including northern parts of Canada. Such products could eventually be obtained through downscaling. In this study, we extended the spectral combination theory to simultaneously downscale spatiotemporally the 3o spatial coarse resolution of GRACE to 0.25o degrees resolution and monthly coarse resolution to daily resolution. This method combines the monthly gravity field solution of GRACE and daily hydrological model products in the form of both low and high-frequency signals to produce high spatiotemporal resolution TWSA and GWSA products. The main contribution and originality of this study are to comprehensively and simultaneously consider GRACE and hydrological variables and their uncertainties to form the estimator in the spectral domain. Therefore, it is predicted that we reach downscale products with an acceptable accuracy.

Keywords: GRACE satellite, groundwater storage, spectral combination, terrestrial water storage

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Authors: Gila Kurtz, Dan Kohen Vacs

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Social robots (SR) is an emerging field striving to deploy computers capable of resembling human shapes and mimicking human movements, gestures, and behaviors. The evolving capability of SR to interact with human offers groundbreaking ways for learning and training opportunities. Studies show that SR can offer instructional experiences for fostering creativity, entertainment, enjoyment, and curiosity. These added values are essential for empowering instructional opportunities as gamified learning experiences. We present our project focused on deploying an activity to be experienced in an escape room aimed at team-based learning scaffolded by an SR, NAO. An escape room is a well-known approach for gamified activities focused on a simulated scenario experienced by team-based participants. Usually, the simulation takes place in a physical environment where participants must complete a series of challenges in a limited amount of time. During this experience, players learn something about the assigned topic of the room. In the current learning simulation, students must "save the nation" by locating sensitive information stolen and stored in a vault of four locks. Team members have to look for hints and solve riddles mediated by NAO. Each solution provides a unique code for opening one of the four locks. NAO is also used to provide ongoing feedback on the team's performance. We captured the proceeding of our activity and used it to conduct an evaluation study among ten experts in related areas. The experts were interviewed on their overall assessment of the learning activity and their perception of the added value related to the robot. The results were very encouraging on the feasibility that NAO can serve as a motivational tutor in adults' collaborative game-based learning. We believe that this study marks the first step toward a template for developing innovative team-based training using escape rooms supported by a humanoid robot.

Keywords: social robot, NAO, learning, team based activity, escape room

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Authors: Mebruka Mohammed, Daniel Bisrat, Asfaw Debella, Tarekegn Birhanu

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Lack of quality control standards for medicinal plants and their preparations is considered major barrier to their integration in to effective primary health care in Ethiopia. Poor quality herbal preparations led to countless adverse reactions extending to death. Denial of penetration for the Ethiopian medicinal plants in to the world’s booming herbal market is also another significant loss resulting from absence of herbal quality control system. Thus, in the present study, Gnidia stenophylla Gilg (popular antimalarial plant of south eastern Ethiopia), is standardized and a full monograph is produced that can serve as a guideline in quality control of the crude drug. Morphologically, the roots are found to be cylindrical and tapering towards the end. It has a hard, corky and friable touch with saddle brown color externally and it is relatively smooth and pale brown internally. It has got characteristic pungent odor and very bitter taste. Microscopically it has showed lignified xylem vessels, wider medullary rays with some calcium oxalate crystals, reddish brown secondary metabolite contents and slender shaped long fibres. Physicochemical standards quantified and resulted: foreign matter (5.25%), moisture content (6.69%), total ash (40.80%), acid insoluble ash (8.00%), water soluble ash (2.30%), alcohol soluble extractive (15.27%), water soluble extractive (10.98%), foaming index (100.01 ml/g), swelling index (7.60 ml/g). Phytochemically: Phenols, flavonoids, steroids, tannins and saponins were detected in the root extract; TLC and HPLC fingerprints were produced and an analytical marker was also tentatively characterized as 3-(3,4-dihydro-3,5-dihydroxy-2-(4-hydroxy-5-methylhex-1-en-2-yl)-7-methoxy-4-oxo-2H-chromen-8-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one. Residue wise pesticides (i.e. DDT, DDE, g-BHC) and radiochemical levels fall below the WHO limit while Heavy metals (i.e. Co, Ni, Cr, Pb, and Cu), total aerobic count and fungal load lie way above the WHO limit. In conclusion, the result can be taken as signal that employing non standardized medicinal plants could cause many health risks of the Ethiopian people and Africans’ at large (as 80% of inhabitants in the continent depends on it for primary health care). Therefore, following a more universal approach to herbal quality by adopting the WHO guidelines and developing monographs using the various quality parameters is inevitable to minimize quality breach and promote effective herbal drug usage.

Keywords: Gnidia stenophylla Gilg, standardization/monograph, pharmacognostic, residue/impurity, quality

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Authors: John Dorrell, Matthew Ambrosia, Abilash

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This paper employs econometric analysis to quantify the potential profit wind farms can receive by allocating excess wind energy to power bitcoin mining machines. Cryptocurrency mining consumes a substantial amount of electricity worldwide, and wind energy produces a significant amount of energy that is lost because of the intermittent nature of the resource. Supply does not always match consumer demand. By combining the weaknesses of these two technologies, we can improve efficiency and a sustainable path to mine cryptocurrencies. This paper uses historical wind energy from the ERCOT network in Texas and cryptocurrency data from 2000-2021, to create 4-year return on investment projections. Our research model incorporates the price of bitcoin, the price of the miner, the hash rate of the miner relative to the network hash rate, the block reward, the bitcoin transaction fees awarded to the miners, the mining pool fees, the cost of the electricity and the percentage of time the miner will be running to demonstrate that wind farms generate enough excess energy to mine bitcoin profitably. Excess wind energy can be used as a financial battery, which can utilize wasted electricity by changing it into economic energy. The findings of our research determine that wind energy producers can earn profit while not taking away much if any, electricity from the grid. According to our results, Bitcoin mining could give as much as 1347% and 805% return on investment with the starting dates of November 1, 2021, and November 1, 2022, respectively, using wind farm curtailment. This paper is helpful to policymakers and investors in determining efficient and sustainable ways to power our economic future. This paper proposes a practical solution for the problem of crypto mining energy consumption and creates a more sustainable energy future for Bitcoin.

Keywords: bitcoin, mining, economics, energy

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Authors: Yatimah Alias, Tilagam Marimuthu, M. R. Mahmoudian, Sharifah Mohamad

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The rapid growth of science and technology in energy and environmental fields has enlightened the substantial importance of the conducting polymer and metal composite materials engineered at nano-scale. In this study, polypyrrole-cobalt composites (PPy-Co Cs) and polypyrrole-nickel oxide composites (PPy-NiO Cs) were prepared by a simple and facile chemical polymerization method with an aqueous solution of pyrrole monomer in the presence of metal salt. These composites then fabricated into non-enzymatic hydrogen peroxide (H2O2) and glucose sensor. The morphology and composition of the composites are characterized by the Field Emission Scanning Electron Microscope, Fourier Transform Infrared Spectrum and X-ray Powder Diffraction. The obtained results were compared with the pure PPy and metal oxide particles. The structural and morphology properties of synthesized composites are different from those of pure PPy and metal oxide particles, which were attributed to the strong interaction between the PPy and the metal particles. Besides, a favorable micro-environment for the electrochemical oxidation of H2O2 and glucose was achieved on the modified glassy carbon electrode (GCE) coated with PPy-Co Cs and PPy-NiO Cs respectively, resulting in an enhanced amperometric response. Both PPy-Co/GCE and PPy-NiO/GCE give high response towards target analyte at optimum condition of 500 μl pyrrole monomer content. Furthermore, the presence of pyrrole monomer greatly increases the sensitivity of the respective modified electrode. The PPy-Co/GCE could detect H2O2 in a linear range of 20 μM to 80 mM with two linear segments (low and high concentration of H2O2) and the detection limit for both ranges is 2.05 μM and 19.64 μM, respectively. Besides, PPy-NiO/GCE exhibited good electrocatalytic behavior towards glucose oxidation in alkaline medium and could detect glucose in linear ranges of 0.01 mM to 0.50 mM and 1 mM to 20 mM with detection limit of 0.33 and 5.77 μM, respectively. The ease of modifying and the long-term stability of this sensor have made it superior to enzymatic sensors, which must kept in a critical environment.

Keywords: metal oxide, composite, non-enzymatic sensor, polypyrrole

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Authors: Victoria Bessonova, Robert Dorrell, Nina Dethlefs, Evdokia Tapoglou, Katharine York

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As the global pursuit of renewable energy intensifies, offshore wind farms have emerged as a promising solution to combat climate change. The global offshore wind installed capacity is projected to increase 56-fold by 2055. However, the impacts of climate change, particularly changes in wave climate, are not widely understood. Offshore wind installation and maintenance activities often require specific weather windows, characterized by calm seas and low wave heights, to ensure safe and efficient operations. However, climate change-induced alterations in wave characteristics can reduce the availability of suitable weather windows, leading to delays and disruptions in project timelines. it applied the operational limits of installation and maintenance vessels to past and future climate wave projections. This revealed changes in the annual and monthly accessibility of offshore wind farms at key global development locations. When accessibility is only defined by significant wave height, spatial patterns in the annual accessibility roughly follow changes in significant wave height, with increased availability where significant wave height is decreasing. This resulted in a 1-6% increase in Europe and North America and a similar decrease in South America, Australia and Asia. Monthly changes suggest unchanged or slightly decreased (1-2%) accessibility in summer months and increased (2-6%) in winter. Further assessment includes assessing the sensitivity of accessibility to operational limits defined by wave height combined with wave period and wave height combined with wind speed. Results of this assessment will be included in the presentation. These findings will help stakeholders inform climate change adaptations in installation and maintenance planning practices.

Keywords: climate change, offshore wind, offshore wind installation, operations and maintenance, wave climate, wind farm accessibility

Procedia PDF Downloads 90