Search results for: metals transition

Authors: A. Threepanich, S. Youngme, P. Praipipat

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Although ground egg shells had the ability to eliminate lead in water, their efficiency may decrease in a case of contaminating of other cations such as Na⁺, Ca²⁺ in the water. The development of ground egg shells may solve this problem in which metal oxides are a good choice for this case since they have the ability to remove any heavy metals including lead in the water. Therefore, this study attempts to use this advantage for improving ground egg shells for the specific lead removal efficiency in the water. X-ray fluorescence (XRF) technique was used for the chemical element contents analysis of ground egg shells (GES) and ground egg shells with metal oxide (GESM), and Transmission electron microscope (TEM) technique was used to examine the material sizes. The batch test studies were designed to investigate the factor effects on dose (5, 10, 15 grams), pH (5, 7, 9), and settling time (1, 3, 5 hours) for the lead removal efficiency in the water. The XRF analysis results showed GES contained calcium (Ca) 91.41% and Silicon (Si) 4.03% and GESM contained calcium (Ca) 91.41%, Silicon (Si) 4.03%, and Iron (Fe) 3.05%. TEM results confirmed the sizes of GES and GESM in the range of 1-20 nm. The batch test studies showed the best optimum conditions for the lead removal in the water of GES and GESM in dose, pH, and settling time were 10 grams, pH 9, 5 hours and 5 grams, pH 9, 3 hours, respectively. The competing ions (Na⁺ and Ca²⁺) study reported GESM had the higher % lead removal efficiency than GES at 90% and 60%, respectively. Therefore, this result can confirm that adding of metal oxide to ground egg shells helps to improve the lead removal efficiency in the water.

Keywords: nano material, ground egg shells, metal oxide, lead

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Authors: C. Benhamideche

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Fluoroaluminate glasses have been reported as the earliest heavy metal fluoride glasses. By comparison with flurozirconate glasses, they offer a set of similar optical features, but also some differences in their elastic and chemical properties. In practice they have been less developed because their stability against devitrification is smaller than that of the most stable fluoroziconates. The purpose of this study was to investigate glass formation in systems AlF3-YF3-PbF2-MgF2-MF2 (M= Li, Na, K). Synthesis was implemented at room atmosphere using the ammonium fluoride processing. After fining, the liquid was into a preheated brass mold, then annealed below the glass transition temperature for several hours. The samples were polished for optical measurements. Glass formation has been investigated in a systematic way, using pseudo ternary systems in order to allow parameters to vary at the same time. We have chosen the most stable glass compositions for the determination of the physical properties. These properties including characteristic temperatures, density and proprieties elastic. Glass stability increases in multicomponent glasses. Bulk samples have been prepared for physical characterization. These glasses have a potential interest for passive optical fibers because they are less sensitive to water attack than ZBLAN glass, mechanically stronger. It is expected they could have a larger damage threshold for laser power transmission.

Keywords: fluoride glass, aluminium fluoride, thermal properties, density, proprieties elastic

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Authors: Wang Liguang, Zhang Xueqing

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The build-operate-transfer (BOT) project delivery system has provided effective routes to mobilize private sector funds, innovative technologies, management skills and operational efficiencies for public infrastructure development and have been widely used in China during the last 20 years. Many BOT projects in China will be smoothly transferred to the government soon and the transfer stage, which is considered as the last stage, must be studied carefully and handled well to achieve the overall success of BOT projects. There will be many issues faced by both the public sector and private sector in the transfer stage of BOT projects, including project post-assessment, technology and documents transfer, personal training and staff transition, etc. and sometimes additional legislation is needed for future operation and management of facilities. However, most previous studies focused on the bidding, financing, and building and operation stages instead of transfer stage. This research identifies nine key issues in the transfer stage of BOT projects through a comprehensive study on three cases in China, and the expert interview and expert discussion meetings are held to validate the key issues and give detail analysis. A proposed framework of transfer management is prepared based on the experiences derived and lessons drawn from the case studies and expert interview and discussions, which is expected to improve the transfer management of BOT projects in practice.

Keywords: BOT project, key issues, transfer management, transfer stage

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Authors: Gurjeet Singh, M. K. Pradhan, Ajay Verma

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The plastic industry plays very important role in the economy of any country. It is generally among the leading share of the economy of the country. Since metals and their alloys are very rarely available on the earth. So to produce plastic products and components, which finds application in many industrial as well as household consumer products is beneficial. Since 50% plastic products are manufactured by injection moulding process. For production of better quality product, we have to control quality characteristics and performance of the product. The process parameters plays a significant role in production of plastic, hence the control of process parameter is essential. In this paper the effect of the parameters selection on injection moulding process has been described. It is to define suitable parameters in producing plastic product. Selecting the process parameter by trial and error is neither desirable nor acceptable, as it is often tends to increase the cost and time. Hence optimization of processing parameter of injection moulding process is essential. The experiments were designed with Taguchi’s orthogonal array to achieve the result with least number of experiments. Here Plastic material polypropylene is studied. Tensile strength test of material is done on universal testing machine, which is produced by injection moulding machine. By using Taguchi technique with the help of MiniTab-14 software the best value of injection pressure, melt temperature, packing pressure and packing time is obtained. We found that process parameter packing pressure contribute more in production of good tensile plastic product.

Keywords: injection moulding, tensile strength, poly-propylene, Taguchi

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Authors: A. L. R. Rangel, J. A. M. Chaves, A. P. R. Alves Claro

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Surface modification of titanium and its alloys using TiO2 nanotube growth has been widely studied for biomedical field due to excellent interaction between implant and biological environment. The success of this treatment is directly related to anatase phase formation (TiO2 phase) which affects the cells growth. The aim of this study was to evaluate the phases formed in the nanotubes growth on the Ti-15Mo surface. Nanotubes were grown by electrochemical anodization of the alloy in ammonium fluoride based glycerol electrolyte for 24 hours at 20V. Then, the samples were annealed at 200°,400°, 450°, 500°, 600°, and 800° C for 1 hour. Contact angles measurements, scanning electron microscopy images and X rays diffraction analysis (XRD) were carried out for all samples. Raman Spectroscopy was used to evaluate TiO2 phases transformation in nanotubes samples as well. The results of XRD showed anatase formation for lower temperatures, while at 800 ° C the rutile phase was observed all over the surface. Raman spectra indicate that this phase transition occurs between 500 and 600 °C. The different phases formed have influenced the nanotubes morphologies, since higher annealing temperatures induced agglutination of the TiO2 layer, disrupting the tubular structure. On the other hand, the nanotubes drastically reduced the contact angle, regardless the annealing temperature.

Keywords: nanotubes, TiO2, titanium alloys, Ti-15Mo

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Authors: Behrooz Movahedi

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Fe-based amorphous feedstock powders are used as the matrix into which various ratios of hard B4C nanoparticles (0, 5, 10, 15, 20 vol.%) as reinforcing agents were prepared using a planetary high-energy mechanical milling. The ball-milled nanocomposite feedstock powders were also sprayed by means of high-velocity oxygen fuel (HVOF) technique. The characteristics of the powder particles and the prepared coating depending on their microstructures and nanohardness were examined in detail using nanoindentation tester. The results showed that the formation of the Fe-based amorphous phase was noticed over the course of high-energy ball milling. It is interesting to note that the nanocomposite coating is divided into two regions, namely, a full amorphous phase region and homogeneous dispersion of B4C nanoparticles with a scale of 10–50 nm in a residual amorphous matrix. As the B4C content increases, the nanohardness of the composite coatings increases, but the fracture toughness begins to decrease at the B4C content higher than 20 vol.%. The optimal mechanical properties are obtained with 15 vol.% B4C due to the suitable content and uniform distribution of nanoparticles. Consequently, the changes in mechanical properties of the coatings were attributed to the changes in the brittle to ductile transition by adding B4C nanoparticles.

Keywords: Fe-based amorphous, B₄C nanoparticles, nanocomposite coating, HVOF

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Authors: Dina H. Gabr, Mona A. El Bannan

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With growing worldwide concern for global warming, green finance has become the fuel that pushes the world to act in combating and mitigating climate change. Coupled with adopting the Paris Agreement and the United Nations Sustainable Development Goals, Green finance became a vital tool in creating a pathway to sustainable development, as it connects the financial world with environmental and societal benefits. This paper provides a comprehensive review of the concepts and definitions of green finance and the importance of 'green' impact investments today. The core challenge in combating climate change is reducing and controlling Greenhouse gas emissions; therefore, this study explores the solutions green finance provides putting emphasis on the use of renewable energy, which is necessary for enhancing the transition to the green economy. With increasing attention to the concept of green finance, multiple forms of green investments and financial tools have come to fruition; the most prominent are green bonds. The rise of green bonds, a debt market to finance climate solutions, provide a promising mechanism for sustainable finance. Following the review, this paper compiles a comprehensive green bond dataset, presenting a statistical study of the evolution of the green bonds market from its first appearance in 2006 until 2021.

Keywords: climate change, GHG emissions, green bonds, green finance, sustainable finance

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Authors: Loredana Elena Nita, Maria Bercea, Aurica P. Chiriac, Iordana Neamtu

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The paper is devoted to the behavior of gels based on poly(itaconic anhydride-co-3, 9-divinyl-2, 4, 8, 10-tetraoxaspiro (5.5) undecane) copolymers, with different ratio between the comonomers, and hyaluronic acid (HA). The gel formation was investigated by small-amplitude oscillatory shear measurements following the viscoelastic behavior as a function of gel composition, temperature and shear conditions. Hyaluronic acid was investigated in the same conditions and its rheological behavior is typical to viscous fluids. In the case of the copolymers, the ratio between the two comonomers influences the viscoelastic behavior, a higher content of itaconic anhydride favoring the gel formation. Also, the sol-gel transition was evaluated according to Winter-Chambon criterion that identifies the gelation point when the viscoelastic moduli (G’ and G”) behave similarly as a function of oscillation frequency. From rheological measurements, an optimum composition was evidenced for which the system presents a typical gel-like behavior at 37 °C: the elastic modulus is higher than the viscous modulus and they are not dependent on the oscillation frequency. The formation of the 3D macroporous network was also evidenced by FTIR spectra, SEM microscopy and chemical imaging. These hydrogels present a high potential as drug delivery systems.

Keywords: copolymer, viscoelasticity, gelation, 3D network

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Authors: Masami Usui

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The 21th century has already witnessed the rapid globalization of catastrophes caused by layered political, social, religious, cultural, and environmental conflicts. The post 9/11 literature that reflects these characteristics retells the experiences of those who are, whether directly or indirectly, involved in the globalized catastrophes of enlarging and endangering their boundaries and consequences. With an Irish-Turkish origin, a Dutch and British educational background, and as an American green-card holder, Joseph O’Neill challenges this changing circumstances of the expanding crisis. In his controversial novel, Netherland (2008), O’Neill embodies the deeply-rooted compromises, the transplanted conflicts, and human internalized crisis in post 9/11 New York City. O’Neill presents to us the transition between Netherland to New York with a post-colonial perspective. This internalized conflicts are revised in The Dog (2014) in which a newly-constructing and expanding global city of gold, Dubai, represents the transitional location from New York City. Through these two novels, words and voices are migrating beyond cultural and political boundaries and discussing what a collective mind embodies in this globalized society.  

Keywords: American literature, global literature, cultural studies, political science

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Authors: Habib Onsori, Somayeh Akrami, Mohammad Rahmati

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Deafness is the most common sensory disorder with the frequency of 1/1000 in many populations. Mutations in the GJB2 (CX26) gene at the DFNB1 locus on chromosome 13q12 are associated with congenital hearing loss. Approximately 80% of congenital hearing loss cases are recessively inherited and 15% dominantly inherited. Mutations of the GJB2 gene, encoding gap junction protein Connexin 26 (Cx26), are the most common cause of hereditary congenital hearing loss in many countries. This report presents two cases of different mutations from Iranian patients with bilateral hearing loss. DNA studies were performed for the GJB2 gene by PCR and sequencing methods. In one of them, direct sequencing of the gene showed a heterozygous T→C transition at nucleotide 604 resulting in a cysteine to arginine amino acid substitution at codon 202 (C202R) in the fourth extracellular domain (TM4) of the protein. The analyses indicate that the C202R mutation appeared de novo in the proband with a possible dominant effect (GenBank: KF 638275). In the other one, DNA sequencing revealed a compound heterozygous mutation (35delG, 363delC) in the Cx26 gene that is strongly associated with congenital non-syndromic hearing loss (NSHL). So screening the mutations for hearing loss individuals referring to genetics counseling centers before marriage and or pregnancy is recommended.

Keywords: CX26, deafness, GJB2, mutation

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Authors: Okikiola Olusanu

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The us/other relationship between the colonizer and the colonized, which continues to inform the oppression of Africans and highlights the intersectional oppression of postcolonial African women because of the colonialization of the identity of African women, inspired this poem. It reflects 'the body' and the 'embodied' as it journeys through the constructed distance between the white feminine body and colonized bodies in the context of travel. Through vivid imagery, repetition, and powerful language, this poem analyzes the effect of otherness on African women as they struggle with their internalized otherness and a poor sense of belonging, which hinges on the politics of difference which makes it impossible to complement the sameness of another within the liminal space of transition. This poem examines the discourse on the complexities of migration for the African woman by critically examining bodies, space, mobility, and how they interact. Our focus is on their relationship and how it affects African women's place and pace when moving to and through the First World. Through literary and feminist perspectives, this study aims to represent the portrait of the African woman and to decolonize the concept of border. It seeks to address the uniqueness of the African woman’s body, not as the same or different, but as distinct and wholesome to foster fairness, friendship, belonging, and equity in travel. To develop our argument and to establish our findings, we look at the dynamics of the oppression of the postcolonial African woman's body and her resistance.

Keywords: body, identity, African woman, decolonization

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Authors: Littlelet N. Scarlet, Kamaluddin Abdur-Rashid, Paul T. Maragh, Tara Dasgupta

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Aminophosphines are a privileged class of ancillary ligands with emerging importance in homogeneous catalysis. The unique combination of soft phosphorus (P) and hard nitrogen (N) centres affords a variety of transition metal complexes as potential pre-catalysts for synthetically useful reactions. Herein three ligand systems will be reported; two bidentate ligands - (S)-8-(diphenyl-phosphino)-1,2,3,4-tetrahydronaphthalen-1-amine, (S)THNANH2, and (Rc)-1-((Sp)-2-diphenylphosphino) ferrocenylethylamine, (RcSp)PPFNH2 - and a tridentate (Rc)-1-((Sp)-2-diphenylphosphino) ferrocenylimino-pyridine, (RcSp)PPFNNH2 ligand; the latter prepared from the condensation of selected ferrocene aminophosphines with pyridine-2-carboxaldehyde. Suitable combinations of these aminophosphine ligands with ruthenium precursors have afforded highly efficient systems for the asymmetric hydrogenation and transfer hydrogenation of selected ketones in 2-propanol. The Ru-(S)THNANH2 precatalyst was the most efficient in the asymmetric hydrogenation of selected ketones with 100% conversions within 4 hours at a catalyst loading of 0.1 mol%. The Ru-(RcSp)PPFNNH2 precatalyst was the most efficient in the asymmetric transfer hydrogenation of the ketones with conversions as high as 98% with 0.1 mol% catalyst. However, the enantioselectivities were generally low.

Keywords: aminophosphine, asymmetric hydrogenation, homogeneous catalysis, ruthenium (II), transfer hydrogenation

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Authors: Nomthandazo Precious Sibiya, Thembisile Patience Mahlangu, Sudesh Rathilal

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Heavy metal removal is critical in the wastewater treatment process due to its numerous harmful effects on human and aquatic life. There are several chemical and physical techniques for removing heavy metals from wastewater, including ion exchange, reverse osmosis, adsorption, electrodialysis, and ultrafiltration. However, adsorption technology has captivated researchers for years due to its low cost, high efficiency, and compatible with the environment. In this study, the adsorption effectiveness of three modified agro-waste materials was explored for the removal of lead from synthetic wastewater: banana peels (BP), orange peels (OP), and sugarcane bagasse (SB). The magnetite (Fe₃O₄) is incorporated with BP, OP, and SB at a ratio of 1:1 to create magnetic biosorbents. Characterization of biosorbents was carried out using and scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX) to investigate surface morphology and elemental compositions, respectively. A series of batch experiments were carried out to investigate the effects of adsorbent mass, agitation time, and initial pH concentration on adsorption behaviour, as well as adsorption isotherms and kinetics. The removal efficiency of lead by the modified agro-waste materials proved to be superior to that of non-modified agro-waste materials. The proof of concept was achieved, and agro-waste materials can be paired with adsorption technology to effectively remove lead from aqueous media. The use of agricultural waste as biosorbents will aid in waste reduction and management.

Keywords: adsorption, isotherms, kinetics, agro waste, nanoparticles, batch

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Authors: Abouzar Kaboudian, Ravi Chaithanya Mysa, Boo Cheong Khoo, Rajeev Kumar Jaiman

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Vortex induced vibrations can significantly affect the effectiveness of structures in aerospace as well as offshore marine industries. The oscillatory nature of the forces resulting from the vortex shedding around bluff bodies can result in undesirable effects such as increased loading, stresses, deflections, vibrations and noise in the structures, and also reduced fatigue life of the structures. To date, most studies concentrate on either the free oscillations or the prescribed motion of the bluff bodies. However, the structures in operation are usually subject to the external oscillatory forces (e.g. due to the platform motions in offshore industries). In this work, we present the effects of the external cross-flow forces on the vortex-induced vibrations of an oscillating cylinder. The effects of the amplitude, as well as the frequency of the external force on the fluid-forces on the oscillating cylinder are carefully studied and presented. Moreover, we present the transition of the response to be dominated by the vortex-induced-vibrations to the range where it is mostly dictated by the external oscillatory forces. Furthermore, we will discuss how the external forces can affect the flow structures around a cylinder. All results are compared against free oscillations of the cylinder.

Keywords: circular cylinder, external force, vortex-shedding, VIV

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Authors: Kolela J Nyembwe, Darlington C. Ashiegbu, Herman J. Potgieter

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Over the past few decades, the demand for metals has increased significantly. This has led to a decrease and decline of high-grade ore over time and an increase in mineral complexity and matrix heterogeneity. In addition to that, there are rising concerns about greener processes and a sustainable environment. Due to these challenges, the mining and metal industry has been forced to develop new technologies that are able to economically process and recover metallic values from low-grade ores, materials having a metal content locked up in industrially processed residues (tailings and slag), and complex matrix mineral deposits. Several methods to address these issues have been developed, among which are ionic liquids (IL), heap leaching, and bioleaching. Recently, the gas phase extraction technique has been gaining interest because it eliminates many of the problems encountered in conventional mineral processing methods. The technique relies on the formation of volatile metal complexes, which can be removed from the residual solids by a carrier gas. The complexes can then be reduced using the appropriate method to obtain the metal and regenerate-recover the organic extractant. Laboratory work on the gas phase have been conducted for the extraction and recovery of aluminium (Al), iron (Fe), copper (Cu), chrome (Cr), nickel (Ni), lead (Pb), and vanadium V. In all cases the extraction revealed to depend of temperature and mineral surface area. The process technology appears very promising, offers the feasibility of recirculation, organic reagent regeneration, and has the potential to deliver on all promises of a “greener” process.

Keywords: gas-phase extraction, hydrometallurgy, low-grade ore, sustainable environment

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Authors: Harikrishna Yadav Nanganuru, Narasimhulu Korrapati

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The demand for the lead (Pb) in the battery industry has been growing for last twenty years. On an average about 2.35 million tons of lead is used in the battery industry. According to the survey of supply and demand battery industry is using 75% of lead produced every year. Due to the increase in battery scrap, secondary lead production has been increasing in this decade. Europe and USA together account for 75% of the world’s secondary lead production. The effluent from used battery scrap consists of high concentrations of lead. Unauthorized disposal of spent batteries, which contain intolerable concentration of lead, into landfills or municipal water canals causes release of Pb into the environment. Lead is one of the toxic heavy metals that have large damaging effects on the human health. Due to its persistence and toxicity, the presence of Pb in drinking water is considered as a special concern. Accumulation of Pb in the human body for long period of time can result in the malfunctioning of some organs. Many technologies have been developed for the removal of lead using microorganisms. In this paper, effluent was taken from the spent battery scrap and was characterized by inductively coupled plasma atomic emission spectrometer. Microorganisms play an important role in removal of lead from the contaminated sites. So, the bacteria were isolated from the effluent. Optimum conditions for the microbial growth and applied for the lead removal. These bacterial cells were immobilized and used for the removal of Pb from the known concentration of metal solution. Scanning electron microscopic (SEM) studies were shown that the Pb was efficiently adsorbed by the immobilized bacteria. From the results of Atomic Absorption Spectroscopy (AAS), 83.40 percentage of Pb was removed in a batch culture.

Keywords: adsorption, effluent, immobilization, lead (Pb)

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Authors: Hosein Ghahremani, MohammadReza Khoshchehre, Pejman Hakemi

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This study involves numerical simulations of a vertical plate-type photo-bioreactor to investigate the performance of Microalgae Spirulina and Control and optimization of parameters for the digital controller by Taguchi method that MATLAB software and Qualitek-4 has been made. Since the addition of parameters such as temperature, dissolved carbon dioxide, biomass, and ... Some new physical parameters such as light intensity and physiological conditions like photosynthetic efficiency and light inhibitors are involved in biological processes, control is facing many challenges. Not only facilitate the commercial production photo-bioreactor Microalgae as feed for aquaculture and food supplements are efficient systems but also as a possible platform for the production of active molecules such as antibiotics or innovative anti-tumor agents, carbon dioxide removal and removal of heavy metals from wastewater is used. Digital controller is designed for controlling the light bioreactor until Microalgae growth rate and carbon dioxide concentration inside the bioreactor is investigated. The optimal values of the controller parameters of the S/N and ANOVA analysis software Qualitek-4 obtained With Reaction curve, Cohen-Con and Ziegler-Nichols method were compared. The sum of the squared error obtained for each of the control methods mentioned, the Taguchi method as the best method for controlling the light intensity was selected photo-bioreactor. This method compared to control methods listed the higher stability and a shorter interval to be answered.

Keywords: photo-bioreactor, control and optimization, Light intensity, Taguchi method

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Authors: Tuba Kizilirmak

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Distinct properties of porous metamaterials have been largely processed for biomedicine requiring a three-dimensional (3D) porous structure engaged with fine mechanical features, biodegradation ability, and biocompatibility. Applications of metamaterials are (i) porous orthopedic and dental implants; (ii) in vitro cell culture of metamaterials and bone regeneration of metamaterials in vivo; (iii) macro-, micro, and nano-level porous metamaterials for sensors, diagnosis, and drug delivery. There are some specific properties to design metamaterials for tissue engineering. These are surface to volume ratio, pore size, and interconnection degrees are selected to control cell behavior and bone ingrowth. In this study, additive manufacturing technique selective laser melting will be used to print the scaffolds. Selective Laser Melting prints the 3D components according to designed 3D CAD models and manufactured materials, adding layers progressively by layer. This study aims to design metamaterials with Ti6Al4V material, which gives benefit in respect of mechanical and biological properties. Ti6Al4V scaffolds will support cell attachment by conferring a suitable area for cell adhesion. This study will control the osteoblast cell attachment on Ti6Al4V scaffolds after the determination of optimum stiffness and other mechanical properties which are close to mechanical properties of bone. Before we produce the samples, we will use a modeling technique to simulate the mechanical behavior of samples. These samples include different lattice models with varying amounts of porosity and density.

Keywords: additive manufacturing, titanium lattices, metamaterials, porous metals

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Authors: Nicolae Constantin, Ştefan Sorohan

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The small and medium wind turbines are running in quite different conditions as compared to the big ones. Consequently, they need also a different approach concerning the structural health monitoring (SHM) issues. There are four main differences between the above mentioned categories: (i) significantly smaller dimensions, (ii) considerably higher rotation speed, (iii) generally small distance between the turbine and the energy consumer and (iv) monitoring assumed in many situations by the owner. In such conditions, nondestructive inspections (NDI) have to be made as much as possible with affordable, yet effective techniques, requiring portable and accessible equipment. Additionally, the turbines and accessories should be easy to mount, dispose and repair. As the materials used for such unit can be metals, composites and combined, the technologies should be adapted accordingly. An example in which the two materials co-exist is the situation in which the damaged metallic skin of a blade is repaired with a composite patch. The paper presents the inspection of the bonding state of the patch, using portable ultrasonic equipment, able to put in place the Lamb wave method, which proves efficient in global and local inspections as well. The equipment is relatively easy to handle and can be borrowed from specialized laboratories or used by a community of small wind turbine users, upon the case. This evaluation is the first in a row, aimed to evaluate efficiency of NDI performed with rather accessible, less sophisticated equipment and related inspection techniques, having field inspection capabilities. The main goal is to extend such inspection procedures to other components of the wind power unit, such as the support tower, water storage tanks, etc.

Keywords: structural health monitoring, small wind turbines, non-destructive inspection, field inspection capabilities

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Authors: Patrick T. Aquino, Jimwel B. Balunday, Cephas Olivier V. Cabatit, Mary Grace Q. Razonable

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In 2023, the Philippine Department of Energy (PDOE) published the National Energy Efficiency and Conservation Plan (NEECP) and Roadmap 2023-2050 to be the basis of a comprehensive program for the efficient supply and economical use of energy. The building sector, as one of the most energy-intensive sectors, shall conform to the energy-conserving design to reduce the use of energy. The concept of Net-Zero Energy Building (NZEB), and its definitions promote to improve energy efficiency of the buildings. The PDOE partnered with Meralco Power Academy to survey and conduct focus group discussions to establish the readiness into NZE-aspiring buildings of government entities. This paper outlines important NZEB principles, best practices from other countries, issues and gaps relating to energy management program, and the recommendations on the development of a framework for NZEB under government building in the Philippines. Results revealed the limitation on specific data to establish a baseline building energy efficiency performance index and significant energy uses; the need to update the Guidelines for Energy Conservation Design of Buildings, including NZEB definition and requirements; appropriate enabling infrastructures and programs to transition government buildings into NZE-aspiring buildings to Nearly Zero Energy Buildings by 2050.

Keywords: NZEB, energy efficiency, buildings, Philippines

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Authors: Nor-Edine Abriak, Mouhamadou Amar, Mahfoud Benzerzour

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The transition to a more sustainable economy is directed by a reduction in the consumption of raw materials in equivalent production. The recovery of byproducts and especially the dredged sediment as mineral addition in cements matrix represents an alternative to reduce raw material consumption and construction sector’s carbon footprint. However, the efficient use of sediment requires adequate and optimal treatment. Several processing techniques have so far been applied in order to improve some physicochemical properties. The heat treatment by calcination was effective in removing the organic fraction and activates the pozzolanic properties. In this article, the effect of the optimized heat treatment of marine sediments in the physico-mechanical and environmental properties of mortars are shown. A finding is that the optimal substitution of a portion of cement by treated sediments by calcination at 750 °C helps to maintain or improve the mechanical properties of the cement matrix in comparison with a standard reference mortar. The use of calcined sediment enhances mortar behavior in terms of mechanical strength and durability. From an environmental point of view and life cycle, mortars formulated containing treated sediments are considered inert with respect to the inert waste storage facilities reference (ISDI-France).

Keywords: sediment, calcination, cement, reuse

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Authors: S. Alqarni, J. C. McCann, A. Palladino, J. J. Loor

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Seven fistulated Holstein cows were used from 3 weeks prepartum to 4 weeks postpartum to determine the relative abundance of 7 different species of ruminal microorganisms. The prepartum diet was based on corn silage. In the postpartum, diet included ground corn, grain by-products, and alfalfa haylage. Ruminal digesta were collected at five times: -14, -7, 10, 20, and 28 days around parturition. Total DNA from ruminal digesta was isolated and real-time quantitative PCR was used to determine the relative abundance of bacterial species. Eubacterium ruminantium and Selenomonas ruminantium were not affected by time (P>0.05). Megasphaera elsdenii and Prevotella bryantii increased significantly postpartum (P<0.001). Conversely, Butyrivibrio proteoclasticus decreased gradually from -14 through 28 days (P<0.001). Fibrobacter succinogenes was affected by time being lowest at day 10 (P=0.02) while Anaerovibrio lipolytica recorded the lowest abundance at -7 d followed by an increase by 20 days postpartum (P<0.001). Overall, these results indicate that changes in diet after parturition affect the abundance of ruminal bacteria, particularly M. elsdenii (a lactate-utilizing bacteria) and P. bryantii (a starch-degrading bacteria) which increased markedly after parturition likely as a consequence of a higher concentrate intake.

Keywords: rumen bacteria, transition cows, rumen metabolism, peripartal period

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Authors: Khamael M. Abualnaja, Lidija Šiller, Ben R. Horrocks

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The structural characterization of silicon nano crystals (SiNCs) have been carried out using transmission electron microscope (TEM) and atomic force microscopy (AFM). SiNCs are crystalline with an average diameter of 65 nm. Erbium trichloride was added to silicon nano crystals using a simple chemical procedure. Erbium is useful in this context because it has a narrow emission band at ⋍1536 nm which corresponds to a standard optical telecommunication wavelength. The optical properties of SiNCs and erbium-mixed SiNCs samples have been characterized using UV-vis spectroscopy, confocal Raman spectroscopy and photoluminescence spectroscopy (PL). SiNCs and erbium-mixed SiNCs samples exhibit an orange PL emission peak at around 595 nm that arise from radiative recombination of Si. Erbium-mixed SiNCs also shows a weak PL emission peak at ⋍1536 nm that attributed to the intra-4f transition in erbium ions. The intensity of the PL peak of Si in erbium-mixed SiNCs is increased in the intensity up to ×3 as compared to pure SiNCs. It was observed that intensity of 1536 nm peak decreased dramatically in the presence of silicon nano crystals and the PL emission peak of silicon nano crystals is increased. Therefore, the resulted data present that the energy transfer from erbium ions to SiNCs due to the chemical mixing method which used in this work.

Keywords: Silicon Nanocrystals (SiNCs), Erbium Ion, photoluminescence, energy transfer

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Authors: M. A. Karakassides, M. Baikousi, A. Kouloumpis, D. Gournis

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Nanocomposites of Carbon Nanorods (CNRs) with Polystyrene (PS), have been synthesized successfully by means of in situ polymerization process and characterized. Firstly, carbon nanorods with graphitic structure were prepared by the standard synthetic procedure of CMK-3 using MCM-41 as template, instead of SBA-15, and sucrose as carbon source. In order to create an organophilic surface on CNRs, two parts of modification were realized: surface chemical oxidation (CNRs-ox) according to the Staudenmaier’s method and the attachment of octadecylamine molecules on the functional groups of CNRs-ox (CNRs-ODA The nanocomposite materials of polystyrene with CNRs-ODA, were prepared by a solution-precipitation method at three nanoadditive to polymer loadings (1, 3 and 5 wt. %). The as derived nanocomposites were studied with a combination of characterization and analytical techniques. Especially, Fourier-transform infrared (FT-IR) and Raman spectroscopies were used for the chemical and structural characterization of the pristine materials and the derived nanocomposites while the morphology of nanocomposites and the dispersion of the carbon nanorods were analyzed by atomic force and scanning electron microscopy techniques. Tensile testing and thermogravimetric analysis (TGA) along with differential scanning calorimetry (DSC) were also used to examine the mechanical properties and thermal stability -glass transition temperature of PS after the incorporation of CNRs-ODA nanorods. The results showed that the thermal and mechanical properties of the PS/ CNRs-ODA nanocomposites gradually improved with increasing of CNRs-ODA loading.

Keywords: nanocomposites, polystyrene, carbon, nanorods

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Authors: Sylvia Acquah

Abstract:

The assumption that social enterprises are empowering has strong theoretical support, but empirical verification is anecdotal at best. Social enterprises blend social goal with an enterprising idea and therefore in theory these enterprises should provide meaningful jobs that are empowering. Whether jobs created are meaningful, or whether these organizations are practicing social entrepreneurship remains unexplored key questions. This paper addresses these key questions through a comprehensive literature review and an ethnographical study of a Domiciliary Home Care Social Enterprise in the UK. The social entrepreneurs, management and 9 staff members were observed, interviewed and achieves were reviewed and analyzed. In this study, the social entrepreneur’s vision was lost in transition during management change and the organization was only identified as a social enterprise by name. The organization that was set up to tackle lack of continuity in care and create a family of independent carers, was eventually closed down overnight and subjected to investigation by social services and the local council. Also, the ineffectiveness of the organization led to staff being stressed and without the support of the management to help rectify the issues; staff started displaying symptoms of burnout. Social enterprise managers should not only focus on profit maximization or generation, but should equally live up to the core tenets of the enterprise and effectively communicate and gain buy-in of all employees for any changes. Further, there ought to be an independent organization that regulates social enterprises to ensure that they are adhering to their social goals.

Keywords: ethnography, carer, social, enterprise

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Authors: Guozhen Li, Philip Hall, Nick Miles, Tao Wu

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This paper presents a numerical investigation of two horizontally mounted four-lobed swirl pipes in terms of swirl induction effectiveness into flows passing through them. The swirl flows induced by the two swirl pipes have the potential to improve the efficiency of Clean-In-Place procedures in a closed processing system by local intensification of hydrodynamic impact on the internal pipe surface. Pressure losses, swirl development within the two swirl pipe, swirl induction effectiveness, swirl decay and wall shear stress variation downstream of two swirl pipes are analyzed and compared. It was found that a shorter length of swirl inducing pipe used in joint with transition pipes is more effective in swirl induction than when a longer one is used, in that it has a less constraint to the induced swirl and results in slightly higher swirl intensity just downstream of it with the expense of a smaller pressure loss. The wall shear stress downstream of the shorter swirl pipe is also slightly larger than that downstream of the longer swirl pipe due to the slightly higher swirl intensity induced by the shorter swirl pipe. The advantage of the shorter swirl pipe in terms of swirl induction is more significant in flows with a larger Reynolds Number.

Keywords: swirl pipe, swirl effectiveness, CFD, wall shear stress, swirl intensity

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Authors: Anyia Nduka, Aslan Bin Amad Senin

Abstract:

Taking a behavioral perspective of Organization Culture, Strategic Leadership, and performance (OC, SLP). We examine the role of Strategic Leadership as key vicious mechanism linking OC,SLP to the organizational capacities. Given the increasing degree of dependence of modern businesses on the use and scientific discovery of relevant data, research efforts around the entire globe have been accelerated. In today's corporate world, Strategic Leadership is still the most sustainable option of performance and competitive advantage. This is why it is critical to gain a deep understanding of research area and to strengthen new collaborative networks in efforts to support research transition towards these integrative efforts. This bibliometric analysis is aimed to examine global trends in OC,SLP research based on publication output, author co-authorships, and co-occurrences of author keywords among authors and affiliated countries. 2829 journal articles were retrieved from the Scopus database Between 1974 and 2021. From the research findings, there is a significant increase in number of publications with strong global collaboration (e.g., USA & UK). We also discovered that while most countries/territories without affiliations were centered in developing countries, the outstanding performance of Asian countries and the volume of their collaborations should be emulated.

Keywords: organizational culture, strategic leadership, organizational resilience, performance

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Authors: G. K. Awari, Vishwajeet V. Ambade, S. W. Rajurkar

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The field of additive manufacturing is growing, and discoveries are being made. 3D printing machines are also being developed to accommodate a wider range of 3D printing materials, including plastics, metals (metal AM powders), composites, filaments, and other materials. There are numerous printing materials available for industrial additive manufacturing. Such materials have their unique characteristics, advantages, and disadvantages. In order to avoid errors in additive manufacturing, key elements such as 3D printing material type, texture, cost, printing technique and procedure, and so on must be examined. It can be complex to select the best material for a particular job. Polylactic acid (PLA) is made from sugar cane or cornstarch, both of which are renewable resources. "Black plastic" is another name for it. Because it is safe to use and print, it is frequently used in primary and secondary schools. This is also how FDM screen printing is done. PLA is simple to print because of its low warping impact. It's also possible to print it on a cold surface. When opposed to ABS, it allows for sharper edges and features to be printed. This material comes in a wide range of colours. Polylactic acid (PLA) is the most common material used in fused deposition modelling (FDM). PLA can be used to print a wide range of components, including medical implants, household items, and mechanical parts. The mechanical behaviour of the printed item is affected by variations in infill patterns that are subjected to compressive tests in the current investigation to examine their behaviour under compressive stresses.

Keywords: fused deposition modelling, polylactic acid, infill density, infill pattern, compressive strength

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Authors: R. Shrestha, D. P. Subedi, R. B. Tyata, C. S. Wong,

Abstract:

In this paper, a technique for the determination of electron temperatures and electron densities in atmospheric pressure Argon/air discharge by the analysis of optical emission spectra (OES) is reported. The discharge was produced using a high voltage (0-20) kV power supply operating at a frequency of 27 kHz in parallel electrode system, with glass as dielectric. The dielectric layers covering the electrodes act as current limiters and prevent the transition to an arc discharge. Optical emission spectra in the range of (300nm-850nm) were recorded for the discharge with different inter electrode gap keeping electric field constant. Electron temperature (Te) and electron density (ne) are estimated from electrical and optical methods. Electron density was calculated using power balance method. The optical methods are related with line intensity ratio from the relative intensities of Ar-I and Ar-II lines in Argon plasma. The electron density calculated by using line intensity ratio method was compared with the electron density calculated by stark broadening method. The effect of dielectric thickness on plasma parameters (Te and ne) have also been studied and found that Te and ne increases as thickness of dielectric decrease for same inter electrode distance and applied voltage.

Keywords: electron density, electron temperature, optical emission spectra,

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Authors: Hamza Javar Magnier, Leslie V. Woodcock

Abstract:

It has been reported that at temperatures above the critical there is no “continuity of liquid and gas”, as originally hypothesized by van der Waals. Rather, both gas and liquid phases, with characteristic properties as such, extend to supercritical temperatures. Each phase is bounded by the locus of a percolation transition, i.e. a higher-order thermodynamic phase change associated with percolation of gas clusters in a large void, or liquid interstitial vacancies in a large cluster. Between these two-phase bounds, it is reported there exists a mesophase that resembles an otherwise homogeneous dispersion of gas micro-bubbles in liquid (foam) and a dispersion of liquid micro-droplets in gas (mist). Such a colloidal-like state of a pure one-component fluid represents a hitherto unchartered equilibrium state of matter besides pure solid, liquid or gas. Here we provide compelling evidence, from molecular dynamics (MD) simulations, for the existence of this supercritical mesophase and its colloidal nature. We report preliminary results of computer simulations for a model fluid using a simplistic representation of atoms or molecules, i.e. a hard-core repulsion with an attraction so short that the atoms are referred to as “adhesive spheres”. Molecular clusters, and hence percolation transitions, are unambiguously defined. Graphics of color-coded clusters show colloidal characteristics of the supercritical mesophase.

Keywords: critical phenomena, mesophase, supercritical, square-well, critical parameters

Procedia PDF Downloads 426