Search results for: stress formation

Authors: Burak Bal, Demircan Canadinc

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Dynamic strain aging (DSA), resulting from the reorientation of C-Mn clusters in the core of dislocations, can provide a strain hardening mechanism. In addition, in Hadfield steel, negative strain rate sensitivity is observed due to the DSA. In our study, we incorporated dynamic strain aging onto crystal plasticity computations to predict the local instabilities and corresponding negative strain rate sensitivity. Specifically, the material response of Hadfield steel was obtained from monotonic and strain-rate jump experiments under tensile loading. The strain rate range was adjusted from 10⁻⁴ to 10⁻¹s ⁻¹. The crystal plasticity modeling of the material response was carried out based on Voce-type hardening law and corresponding Voce hardening parameters were determined. The solute pinning effect of carbon atom was incorporated to crystal plasticity simulations at microscale level by computing the shear stress contribution imposed on an arrested dislocation by carbon atom. After crystal plasticity simulations with modifying hardening rule, which takes into account the contribution of DSA, it was seen that the model successfully predicts both the role of DSA and corresponding strain rate sensitivity.

Keywords: crystal plasticity, dynamic strain aging, Hadfield steel, negative strain rate sensitivity

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Authors: H. Chassaigne, S. Gioria, J. Lobo Vicente, D. Carpi, P. Barboro, G. Tomasi, A. Kinsner-Ovaskainen, F. Rossi

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Emerging approaches in the area of exposure to nanomaterials and assessment of human health effects combine the use of in vitro systems and analytical techniques to study the perturbation of the proteome and/or the metabolome. We investigated the modification in the cytoplasmic compartment of the Balb/3T3 cell line exposed to gold nanoparticles. On one hand, the proteomic approach is quite standardized even if it requires precautions when dealing with in vitro systems. On the other hand, metabolomic analysis is challenging due to the chemical diversity of cellular metabolites that complicate data elaboration and interpretation. Differentially expressed proteins were found to cover a range of functions including stress response, cell metabolism, cell growth and cytoskeleton organization. In addition, de-regulated metabolites were annotated using the HMDB database. The "omics" fields hold huge promises in the interaction of nanoparticles with biological systems. The combination of proteomics and metabolomics data is possible however challenging.

Keywords: data processing, gold nanoparticles, in vitro systems, metabolomics, proteomics

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Authors: Anis Eloud, Mohamed Ben Amor

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Tunisia is a semi-arid country on ¾ of its territory. It is characterized by the scarcity of water resources and accentuated by climate variability. The potential water resources are estimated at 4.6 million m3 / year, of which 2.7 million m3 / year represent surface water and 1.9 million m3 / year feed all the layers that make up the renewable groundwater resources. Water available in Tunisia easily exceed health or agricultural salinity standards. Barely 50% of water resources are less than 1.5 g / l divided at 72% of surface water salinity, 20% of deep groundwater and only 8% in groundwater levels. Southern Tunisia has the largest web "of water in the country, these waters are characterized by a relatively high salinity may exceed 4 gl-1. This is the "root of many problems encountered during their operation. In the region of Djérid, Albian wells are numerous. These wells debit a geothermal water with an average flow of 390 L / s. This water is characterized by a relatively high salinity and temperature of which is around 65 ° C at the source. Which promotes the formation of limescale deposits within the water supply pipe and the cooling loss thereby increasing the load in direct relation with enormous expense and circuits to replace these lines when completely plugged. The present work is a study of geothermal water quality of the region Djérid from physico-chemical analyzes.

Keywords: water quality, salinity, geothermal, supply pipe

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Authors: Maciej Zareba, Pawel Dawid

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The integration of serious games into the onboarding process is radically changing the way organizations seek to engage and retain new employees, especially in digital generations such as Millennials (Generation Y) and Generation Z. Serious gamification uses game design elements - such as points, leaderboards and progress indicators - to create interactive, goal-oriented and engaging experiences that facilitate smoother transitions to new roles and acceptance of organizational cultures. The use of serious games in onboarding reduces the stress of starting a new job while accelerating the learning curve through mechanisms that reward achievements, such as completing milestones, connecting with other team members or learning about company values. These tools promote immediate recognition and a sense of belonging to the team and organization, thereby significantly increasing retention and engagement rates. The article also outlines the benefits of using serious games in the onboarding process. It focuses on increasing employee motivation, accelerating learning about the organization and increasing engagement in the long term. In addition, the paper outlines the potential of using a serious game - 4FactoryManager - in the onboarding process. The article provides useful information for HR professionals who are looking for innovative ways to recruit, onboard and keep the best employees in a changing labor market.

Keywords: HR, oboarding, digital generation, serious games

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Authors: Indu Lata Kanwar, Preeti K. Suresh

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The aim of this study is to fabricate hydroxyapatite based nanocomposites for local drug delivery in periodontal pockets. Hydroxyapatite is chemically similar to the mineral component of bones and hard tissues in mammals. Synthetic biocompatibility and bioactivity with human teeth and bone, making it very attractive for biomedical applications. Nanocomposite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometres (nm), or structures having nano­scale repeat distances between the different phases that make up the material. Nanostructured calcium phosphate materials play an important role in the formation of hard tissues in nature. It is reported that calcium phosphates materials in nano-size can mimic the dimensions of constituent components of calcified tissues. Nano-sized materials offer improved performances compared with conventional materials due to their large surface-to-volume ratios. The specific biological properties of the nanocomposites, as well as their interaction with cells, include the use of bioactive molecules. The approach of periodontal tissue engineering is considered promising to restore bone defect through the use of engineered materials with the aim that they will prohibit the invasion of fibrous connective tissue and help repair the function during bone regeneration.

Keywords: bioactive, hydroxyapatite, nanocomposities, periondontal

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Authors: Long Xumeng

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Place attachment focuses on the emotions and practices between people and their environment, and the influencing factors of place attachment vary depending on the nature of the place. As an important carrier of public slow-moving activities and urban culture, the feelings, cognition, and behaviors of the subjects involved in the use of mountain city trails have become the focus of research in this field. This paper will take Daijiaxiang Cliff Walkway in Yuzhong District, Chongqing City, as an example and analyze the evaluation results and correlation of each factor through questionnaire survey and field observation, using the three scales of Recreational Experience Scale, Satisfaction Scale, and Place Attachment Scale, as well as the intensity of activity, by using SPSS software. The study shows that there is a significant difference between the demographic variables of users' identity and age and the formation of place attachment; the degree of place attachment is significantly positively correlated with the emotion, industry, and service quality of recreational experience; and the recreational experience of the Mountain City Trail is significantly positively correlated with the overall satisfaction. By analyzing the influencing factors of recreational experience, satisfaction and place attachment, the corresponding conclusions and enhancement strategies were drawn to provide references for the renewal and construction of mountain city trails.

Keywords: mountain city trail, place attachment, recreational experience, satisfaction, urban renewal

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Authors: Y. Rae, A. Benaarbia, J. Hughes, Wei Sun

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This paper describes an elasto-visco-plastic computational modelling method which can be used to assess the cyclic plasticity responses of high temperature structures operating under thermo-mechanical loadings. The material constitutive equation used is an improved unified multi-axial Chaboche-Lemaitre model, which takes into account non-linear kinematic and isotropic hardening. The computational methodology is a three-dimensional framework following an implicit formulation and based on a radial return mapping algorithm. The associated user material (UMAT) code is developed and calibrated across isothermal hold-time low cycle fatigue tests for a typical turbine rotor steel for use in finite element (FE) implementation. The model is applied to a realistic industrial gas turbine rotor, where the study focuses its attention on the deformation heterogeneities and critical high stress areas within the rotor structure. The potential improvements of such FE visco-plastic approach are discussed. An integrated life assessment procedure based on R5 and visco-plasticity modelling, is also briefly addressed.

Keywords: unified visco-plasticity, thermo-mechanical, turbine rotor, finite element modelling

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Authors: Ramita Vongrat, Pornsri Sapsrithong, Manit Nithitanakul

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In this work, blends of polyamide 6 (PA6) and polybutylene terephthalate (PBT) were successfully prepared. The effect of epoxidized natural rubber (ENR-25) and n butyl acrylate glycidyl methacrylate ethylene (EBa-GMA) as a compatibilizer on properties of PA6/PBT blends was also investigated by varying amount of ENR-50 and EBa-GMA, i.e., 0, 0.1, 0.5, 5 and 10 phr. All blends were prepared and shaped by using twin-screw extruder at 230 °C and injection molding machine, respectively. All test specimens were characterized by phase morphology, impact strength, tensile, flexural properties, and hardness. The results exhibited that phase morphology of PA6/PBT blend without compatibilizer was incompatible. This could be attributed to poor interfacial adhesion between the two polymers. SEM micrographs showed that the addition of ENR-25 and EBa-GMA improved the compatibility of PA6/PBT blends. With the addition of ENR-50 as a compatibilizer, the uniformity and the maximum reduction of dispersed phase size were observed. Additionally, the results indicate that, as the amount of ENR-25 increased, and EBa-GMA increased, the mechanical properties, including stress at the peak, tensile modulus, and izod impact strength, were also improved.

Keywords: EBa-GMA, epoxidized natural rubber-25, polyamide 6, polybutylene terephthalate

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Authors: Zikora K. G. Anyaegbunam, Annabel A. Nnawuihe, Ngozi J. Anyaegbunam, Emmanuel A. Eze

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The discovery and production of new antibiotics is unavoidable in the fight against drug-resistant bacteria. However, this is only part of the problem; we have never really had medications that could completely eradicate an infection. All pathogens create a limited number of dormant persister cells that are resistant to antibiotic treatment. When the concentration of antibiotics decreases, surviving persisters repopulate the population, resulting in a recurrent chronic infection. Bacterial populations have an alternative survival strategy to withstand harsh conditions or antibiotic exposure, in addition to the well-known methods of antibiotic resistance and biofilm formation. Persister cells are a limited subset of transiently antibiotic-tolerant phenotypic variations capable of surviving high-dose antibiotic therapy. Persisters that flip back to a normal phenotype can restart growth when antibiotic pressure drops, assuring the bacterial population's survival. Persister cells have been found in every major pathogen, and they play a role in antibiotic tolerance in biofilms as well as the recalcitrance of chronic infections. Persister cells has been implicated to play a role in the establishment of antibiotic resistance, according to growing research. Thusthe need to basically elucidate the biology of persisters and how they are linked to antibiotic resistance, and as well it's link to diseases.

Keywords: persister cells, phenotypic variations, repopulation, mobile genetic transfers, antibiotic resistance

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Authors: Naci Büyükkaracığan, Hasan Uzun

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Flood is the event which damage to the surrounding lands, residential places, infrastructure and vibrant, because of the streams overflow events from its bed for several reasons. Flood is a natural formation which develops due to its region's climatic conditions, technical and topographical characteristics. However, factors causing floods with global warming caused by human activity are events such as uncontrolled urbanization. Floods in Turkey are natural disasters which cause huge economic losses after the earthquake. At the same time, the flood disaster is one of the most observed hydrometeorological disasters, compared to 30%, in Turkey. Every year, there are around 200 flood-flood disasters and the disaster as a result of financial losses of $ 100 million per year are reported to occur in public institutions. The amount allocated for carrying out investment-project activities for reducing and controlling of flood damage control are around US $ 30 million per year. The existence of a linear increase in the number of flood disasters is noteworthy due to various reasons in the last 50 years of observation. In this study, first of all, big events of the flood in Turkey and their reasons were examined. And then, the information about the work to be done in order to prevent flooding by government was given with examples. Meteorological early warning systems, flood risk maps and regulation of urban development studies are described for this purpose. As a result, recommendations regarding in the event of the occurrence of floods disaster management were issues raised.

Keywords: flood, disaster, disaster management, Türkiye

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Authors: Masoud Mahdavi

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Today, developed and industrial cities have all kinds of sewage and water transfer canals, subway tunnels, infrastructure facilities, etc., which have caused underground cavities to be created under the buildings. The presence of these cavities causes behavioral changes in the structural behavior that must be fully evaluated. In the present study, using Abaqus finite element software, the effect of cavities with 0.5 and 1.5 meters in diameter at a depth of 2.5 meters from the earth's surface (with a circular cross-section) on the performance of the foundation and the ground (soil) has been evaluated. For this purpose, the Kobe earthquake was applied to the models for 10 seconds. Also, pore water pressure and weight were considered on the models to get complete results. The results showed that by creating and increasing the diameter of circular cavities in the soil, three indicators; 1) von Mises stress, 2) displacement and 3) plastic strain have had oscillating, ascending and ascending processes, respectively, which shows the relationship between increasing the diameter index of underground cavities and structural indicators of structure-foundation-soil.

Keywords: underground excavations, foundation, structural substrates, Abaqus software, Kobe earthquake, time history analysis

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Authors: Sadia Saleem

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Infertility is a global health concern that may have a long-lasting effect on the psychosocial functioning of an individual. Rich research evidence has shown that women with infertility are at greater risk of adverse psychological experiences than men. The culture plays a risk factor when it comes to infertility. Family is considered as a central focus of a collectivistic culture like Pakistan and having children is the key factor that determines the quality of a marital relationship, individual well-being and overall standing in the society. In this collectivistic cultural context, women usually get the blame and experience more psychological distress and social isolation. A total sample of 121 (M 28.17, SD 4.73) women with primary infertility selected through purposive sampling were tested using Emotional Disclosure Questionnaire, Couple Satisfaction Index and Depression Anxiety Stress Scale. The results indicate that negative emotional disclosure positively mediates the relationship between marital satisfaction and mental health problems (p < .001) in women with primary infertility. The results are discussed in terms of psychosocial counseling and family psychoeducation in Pakistani collectivistic cultural context.

Keywords: infertility, couple satisfaction, emotional disclosure, mental health

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Authors: Belkacem Chebil Sonia, Bensalem Wacef

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The majority of ball end milling models includes only the influence of cutting parameters (cutting speed, feed rate, depth of cut). Furthermore, this influence is studied in most of works on cutting force. Therefore, this study proposes an accurate ball end milling process modeling which includes also the influence of tool workpiece inclination. In addition, a characterization of residual stresses resulting of thermo mechanical loading in the workpiece was also presented. Moreover, the study of the influence of tool workpiece inclination and cutting parameters was made on residual stresses distribution. In order to achieve the predetermination of cutting forces and residual stresses during a milling operation, a thermo mechanical three-dimensional numerical model of ball end milling was developed. Furthermore, an experimental companion of ball end milling tests was realized on a 5-axis machining center to determine the cutting forces and characterize the residual stresses. The simulation results are compared with the experiment to validate the Finite Element Model and subsequently identify the optimum inclination angle and cutting parameters.

Keywords: ball end milling, cutting forces, cutting parameters, residual stress, tool-workpiece inclination

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Authors: David Chung

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The development of seventeenth-century French harpsichord music is enigmatic in several respects. Although little is known about the formation of this style before 1650 (we have names of composers, but no surviving music), the style has attained a high degree of refinement and sophistication in the music of the earliest known masters (e.g. Chambonnières, Louis Couperin and D’Anglebert). In fact, how the seventeenth-century musicians acquired the skills of their art remains largely steeped in mystery, as the earliest major treatise on French keyboard pedagogy was not published until 1702 by Saint Lambert. This study fills this lacuna by surveying some twenty recently-rediscovered manuscripts, which offer ample materials for revisiting key issues pertaining to seventeenth-century harpsichord pedagogy. By analyzing the musical contents, the verbal information and explicit notation (such as written-out ornaments and rhythmic effects), this study provides a rich picture of the process of learning at the time, with engaging details of performance nuances often lacking in tutors and treatises. Of even greater significance, that creative skills (such as continuo and ornamentation) were taught alongside fundamental knowledge (solfèges, note values, etc.) at the earliest stage of learning offers fresh challenge for modern pedagogues to rethink how harpsichord pedagogy can be revamped to cater for our own pedagogical and aesthetic needs.

Keywords: French, harpsichord, pedagogy, seventeenth century

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Authors: Al-Braa Kashegari, Ali M. El-Halawany, Akram A. Shalabi, Sabrin R. M. Ibrahim, Hossam M. Abdallah

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Chemical investigation of Chrozophora oblongifolia resulted in the isolation of five major compounds that were identified as apeginin-7-O-glucoside (1), quercetin-3-O-glucuronic acid (2), quercetin-3-O-glacturonic acid (3), rutin (4), and 1,3,6-trigalloyl glucose (5). The identity of isolated compounds was assessed by different spectroscopic methods, including one- and two-dimensional NMR. The isolated compounds were tested for their antioxidant activity using different assays viz., DPPH, FRAP, ABTS, ORAC, and metal chelation effects. In addition, the inhibition of target enzymes involved in the metabolic syndrome, such as alpha-glucosidase and pancreatic lipase, were carried out. Moreover, the effect of the compounds on the advanced glycation end-products (AGEs) as one of the major complications of oxidative stress and hyperglycemia in metabolic syndromes were carried out using BSA‐fructose (bovine serum albumin), BSA-methylglyoxal, and arginine methylglyoxal models. The pure isolates showed a protective effect in metabolic syndromes as well as promising antioxidant activity. The results showed potent activity of compound 5 in all measured parameters meanwhile, none of the tested compounds showed activity against pancreatic lipase.

Keywords: Chrozophora oblongifolia, antioxidant, pancreatic lipase, metabolic syndromes

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Authors: Son Nguyen, Thanh Van, Ly Le

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Ca2+ - dependent calmodulin kinase IIa (CaMKIIa) has recently been found to associate with protein tau missorting and polymerization in Alzheimer’s Disease (AD). However, there has yet inhibitors targeting CaMKIIa to investigate the correlation between CaMKIIa activity and protein tau polymer formation. Combining virtual screening and our statistics in binding contribution scoring function (BCSF), we rationally identified potential compounds that bind to specific CaMKIIa active site and specificity-affinity distribution of the ligand within the active site. Using molecular dynamics simulation, we identified structural stability of CaMKIIa and potent inhibitors, and site-directed bonding, separating non-specific and specific molecular interaction features. Despite of variation in confirmation of simulation time, interactions of the potent inhibitors were found to be strongly associated with the unique chemical features extracted from molecular binding poses. In addition, competitive inhibitors within CaMKIIa showed an important molecular recognition pattern toward specific ligand features. Our approach combining virtual screening with BCSF may provide an universally applicable method for precise identification in the discovery of compounds.

Keywords: Alzheimer’s disease, Ca 2+ -dependent calmodulin kinase IIa, protein tau, molecular docking

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Authors: Abdelkrim Cheriti, Mebarka Belboukhari, Nasser Belboukhari

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Launaea Cass. is a small genus of the family Asteraceae (tribe Lactuceae, subtribe Sonchinae), consisting of 54 species, of which 9 are presented in the flora of Algeria and is mainly distributed in the South Mediterranean, Africa and SW Asia. Plants in the Launaea genus have been used ethnobotanically as bitter stomachic, for treating diarrhea, gastrointestinal tracts, as anti-inflammatory, for skin diseases, treatment of infected wounds, hepatic pains, children fever, as soporific, lactagogue, diuretic and as insecticidal. Antioxidants are vital substances, which possess the ability to protect the body from damages caused by free radical induced oxidative stress. A variety of free radical scavenging antioxidants is found in a number of dietary sources. The main objective of this study focused on the screening of antioxidant activity of Launaea nudicaulis (Asteraceae) extracts. The in vitro antioxidant activity was investigated with DPPH radical scavenging assay. The quantitative evaluation of DPPH scavenging activity showed that n-BuOH and EtOAc extracts are the most active extracts with a percentage of antiradical activity of 89,62% and 71,57% respectively.

Keywords: Launaea, phytochemical, South Algeria, Sahara, endemic specie

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Authors: Abdelghani Tahiri, Youssef Karra, Naima Ait Aabd, Abdelaziz Mimouni

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Saffron (Crocus sativus L.), the most expensive spice in the world derived from the stigmas, is an autumn-flowering and sterile triploid (2n=3x=24) geophyte species that belong to the Iridaceae family. This plant species is mainly propagated vegetatively through the formation of daughter corms from the mother one. Low multiplication rates of daughter corms under natural conditions, along with fungal contamination, significantly reduce the productivity and quality of saffron corms. The development of efficient and sustainable strategies for rapid and large-scale production of selected cultivars of saffron will be desired. For this, the main objective of this work is to improve the vegetative propagation of saffron under ex-vitro conditions. Preliminary results of the influence of increasing doses of humic substances (HS) on the growth and multiplication of corms under greenhouse conditions are evaluated. The obtained data shows that the effect of HS depends on the concentration used and the mode of application. Indeed, the application through irrigation has increased the number of shoots and corms, but it has reduced other parameters. On the other hand, the temporary treatment has improved all observed parameters except for the number of shoots and corms. Results obtained in this work suggest that it is possible to improve the propagation of saffron corms under greenhouse conditions.

Keywords: saffron, Crocus sativus L., corm, humic substances

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Authors: J. Barilla, M. Lokajíček, H. Pisaková, P. Simr

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The final biological effect of ionizing particles may be influenced strongly by some chemical substances present in cells mainly in the case of low-LET radiation. The influence of oxygen may be particularly important because oxygen is always present in living cells. The corresponding processes are then running mainly in the chemical stage of radio biological mechanism. The radical clusters formed by densely ionizing ends of primary or secondary charged particles are mainly responsible for final biological effect. The damage effect depends then on radical concentration at a time when the cluster meets a DNA molecule. It may be strongly influenced by oxygen present in a cell as oxygen may act in different directions: at small concentration of it the interaction with hydrogen radicals prevails while at higher concentrations additional efficient oxygen radicals may be formed. The basic radical concentration in individual clusters diminishes, which is influenced by two parallel processes: chemical reactions and diffusion of corresponding clusters. The given simultaneous evolution may be modeled and analyzed well with the help of Continuous Petri nets. The influence of other substances present in cells during irradiation may be studied, too. Some results concerning the impact of oxygen content will be presented.

Keywords: radiobiological mechanism, chemical phase, DSB formation, Petri nets

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Authors: Awf A. Al-Khan, Michael J. Day, Judith Nimmo, Mourad Tayebi, Stewart D. Ryan, Samantha J. Richardson, Janine A. Danks

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Osteosarcoma (OS) is the most common type of malignant primary bone tumour in dogs. In addition to their critical roles in bone formation and remodeling, parathyroid hormone-related protein (PTHrP) and its receptor (PTHR1) are involved in progression and metastasis of many types of tumours in humans. The aims of this study were to determine the localisation and expression levels of PTHrP and PTHR1 in canine OS tissues using immunohistochemistry and to investigate if this expression is correlated with survival time. Formalin-fixed, paraffin-embedded tissue samples from 44 dogs with known survival time that had been diagnosed with primary osteosarcoma were analysed for localisation of PTHrP and PTHR1. Findings showed that both PTHrP and PTHR1 were present in all OS samples. The dogs with high level of PTHR1 protein (16%) had decreased survival time (P<0.05) compared to dogs with less PTHR1 protein. PTHrP levels did not correlate with survival time (P>0.05). The results of this study indicate that the PTHR1 is expressed differently in canine OS tissues and this may be correlated with poor prognosis. This may mean that PTHR1 may be useful as a prognostic indicator in canine OS and could represent a good therapeutic target in OS.

Keywords: dog, expression, osteosarcoma, parathyroid hormone receptor 1 (PTHR1), parathyroid hormone-related protein (PTHrP), survival

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Authors: K. Raghu, M. N. Vathhsala, Naveen Aradya, Sharth

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River sand is the most preferred fine aggregate for mortar and concrete. River sand is a product of natural weathering of rocks over a period of millions of years and is mined from river beds. Sand mining has disastrous environmental consequences. The excessive mining of river bed is creating an ecological imbalance. This has lead to have restrictions imposed by ministry of environment on sand mining. Driven by the acute need for sand, stone dust or manufactured sand prepared from the crushing and screening of coarse aggregate is being used as sand in the recent past. However manufactured sand is also a natural material and has quarrying and quality issues. To reduce the burden on the environment, alternative materials to be used as fine aggregates are being extensively investigated all over the world. Looking to the quantum of requirements, quality and properties there has been a global consensus on a material – Granulated slags. Granulated slag has been proven as a suitable material for replacing natural sand / crushed fine aggregates. In developed countries, the use of granulated slag as fine aggregate to replace natural sand is well established and is in regular practice. In the present paper Granulated slag has been experimented for usage in mortar. Slags are the main by-products generated during iron and steel production in the steel industry. Over the past decades, the steel production has increased and, consequently, the higher volumes of by-products and residues generated which have driven to the reuse of these materials in an increasingly efficient way. In recent years new technologies have been developed to improve the recovery rates of slags. Increase of slags recovery and use in different fields of applications like cement making, construction and fertilizers help in preserving natural resources. In addition to the environment protection, these practices produced economic benefits, by providing sustainable solutions that can allow the steel industry to achieve its ambitious targets of “zero waste” in coming years. Slags are generated at two different stages of steel production, iron making and steel making known as BF(Blast Furnace) slag and steel slag respectively. The slagging agent or fluxes, such as lime stone, dolomite and quartzite added into BF or steel making furnaces in order to remove impurities from ore, scrap and other ferrous charges during smelting. The slag formation is the result of a complex series of physical and chemical reactions between the non-metallic charge(lime stone, dolomite, fluxes), the energy sources(coal, coke, oxygen, etc.) and refractory materials. Because of the high temperatures (about 15000 C) during their generation, slags do not contain any organic substances. Due to the fact that slags are lighter than the liquid metal, they float and get easily removed. The slags protect the metal bath from atmosphere and maintain temperature through a kind of liquid formation. These slags are in liquid state and solidified in air after dumping in the pit or granulated by impinging water systems. Generally, BF slags are granulated and used in cement making due to its high cementious properties, and steel slags are mostly dumped due to unfavourable physio-chemical conditions. The increasing dump of steel slag not only occupies a plenty of land but also wastes resources and can potentially have an impact on the environment due to water pollution. Since BF slag contains little Fe and can be used directly. BF slag has found a wide application, such as cement production, road construction, Civil Engineering work, fertilizer production, landfill daily cover, soil reclamation, prior to its application outside the iron and steel making process.

Keywords: steel slag, river sand, granulated slag, environmental

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Authors: Víctor Martínez del Rey, Kourosh Nasr Esfahani, Amir Masoud Samani Majd

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In this experimental study, the behaviors of Mixed Oxidant solution components (MOS) and sodium hypochlorite (HYPO) as the most commonly applied surface disinfectant were compared through the effectiveness of chlorine disinfection as a function of the contact time and residual chlorine. In this regard, the variation of pH, free available chlorine (FAC) concentration, and electric conductivity (EC) of disinfection solutions in different concentrations were monitored over 48 h contact time. In parallel, the plant stress activated by chlorine-based disinfectants was assessed by comparing MOS and HYPO. The elements of pH and EC in the plant-soil and their environmental impacts, spread by disinfection solutions were analyzed through several concentrations of FAC including 500 mg/L, 1000 mg/L, and 5000 mg/L in irrigated water. All the experiments were carried out at the service station of Sant Cugat, Spain. The outcomes indicated lower pH and higher durability of MOS than HYPO at the same concentration of FAC which resulted in promising stability of FAC within MOS. Furthermore, the pH and EC value of plant-soil irrigated by NaOCl solution were higher than that of MOS solution at the same FAC concentration. On-site generation of MOS as a safe chlorination option might be considered an imaginary future of smart cities.

Keywords: disinfection, free available chlorine, on-site generation, sodium hypochlorite

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Authors: Bilal Ahmad Ashwar, Inam u nisa, Asima Shah, Adil Gani, Farooq Ahmad Masoodi

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The effects of 5% BHT and green tea extracts (GTE) on the physical, barrier, mechanical, thermal and antioxidant properties of potato starch films were investigated. Results showed both BHT and GTE significantly lowered solubility of films. Addition of BHT significantly decreased water vapour transmission rate. Both BHT and GTE promoted significant increase in the elastic modulus but a decrease in % EAB, however BHT was more effective in increasing elastic modulus. Increase in glass transition temperature (Tg) and enthalpy of transition (ΔH) of films was observed with the incorporation of GTE and BHT. Scanning electron microscopy (SEM) revealed smooth surface of the films. The DPPH radical scavenging ability of both BHT and GTE films were stronger in fatty food stimulant (95% ethanol. The GTE and BHT films were individually applied to fresh beef samples and were stored at 4 0C and room temperature for 10 days. Metmyoglobin formation and lipid oxidation (TBARS) were monitored periodically. The addition of GTE extracts and BHT resulted in decreases in metmyoglobin and TBARS values. We conclude that extracts of GTE and BHT have potential as preservatives for fresh beef.

Keywords: starch film, WVTR, tensile properties, SEM, thermal analysis, DPPH scavenging activity, TBARS, metmyoglobin

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Authors: Morteza Hadi

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This research investigates the potential enhancement of the rollability of Cu-Ge-Ni alloy through the mitigation of microstructural and compositional inhomogeneities via two distinct heat treatment methods: homogenization and solution treatment. To achieve this objective, the alloy with the desired composition was fabricated using a vacuum arc remelting furnace (VAR), followed by sample preparation for microstructural, compositional, and heat treatment analyses at varying temperatures and durations. Characterization was conducted employing optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), and Vickers hardness testing. The results obtained indicate that a minimum duration of 10 hours is necessary for adequate homogenization of the alloy at 750°C. This heat treatment effectively removes coarse dendrites from the casting microstructure and significantly reduces elemental separations. However, despite these improvements, the presence of a second phase with markedly different hardness from the matrix results in poor rolling ability for the alloy. The optimal time for solution treatment at various temperatures was determined, with the most effective cycle identified as 750°C for 2 hours, followed by rapid quenching in water. This process induces the formation of a single-phase microstructure and complete elimination of the second  phase, as confirmed by X-ray diffraction analysis. Results demonstrate a reduction in hardness by 30 Vickers, and the elimination of microstructural unevenness enables successful thickness reduction by up to 50% through rolling without encountering cracking.

Keywords: Cu-Ge-Ni alloy, homogenization. solution treatment, rollability

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Authors: Rorlinda Yusof, Siti Aishah Hassan, Afifah Mohamad Radzi, Mohd Hakimie Zainal Abidin, Amran Rasli, Inderbir Sandhu

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The purpose of this study is to examine the self-identities of gifted and talented students and the relationship between self-identity and academic accomplishment. A random sample of 300 students enrolled in a secondary education programme at the Pusat GENIUS@pintar Negara was chosen as respondents of a 151-item holistic-identity component development tool. The validity of the instrument was assessed using Principal Components Analysis and Factor Analysis via an inter-Item Correlation Matrix (Loading values 0.44 to 0.86), which resulted in the formation of eight dimensions. The Cronbach's Alpha was calculated to determine the instrument's reliability (the overall result was 0.98). The results showed that students' holistic-identity profiles were relatively high (mean=4.09, standard deviation=0.449). In addition, spiritual identity received the greatest mean score (4.34) out of the eight components of identity investigated, while leadership identity received the lowest mean score (3.88). A conceptual framework for Islamic school leadership is recommended to implement spiritual values without differentiation to harmonize spiritual and intellectual intelligence among all the students. Some benchmarking studies with other centres for gifted and talented students are recommended for further research.

Keywords: holistic self-identity, academic achievement, self-development programme, counselling services, gifted and talented students

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Authors: G. A. Rombach, A. Faron

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Crack formation and growth in reinforced concrete members are, in many cases, the cause of the collapse of technical structures. Such serious failures impair structural behavior and can also damage property and persons. An intensive investigation of the crack propagation is indispensable. Numerical methods are being developed to analyze crack growth in an element and to detect fracture failure at an early stage. For reinforced concrete components, however, further research and action are required in the analysis of shear cracks. This paper presents numerical simulations and continuum mechanical modeling of bending shear crack propagation in a three-dimensional reinforced concrete beam without transverse reinforcement. The analysis will provide a further understanding of crack growth and redistribution of inner forces in concrete members. As a numerical method to map discrete cracks, the extended finite element method (XFEM) is applied. The crack propagation is compared with the smeared crack approach using concrete damage plasticity. For validation, the crack patterns of real experiments are compared with the results of the different finite element models. The evaluation is based on single span beams under bending. With the analysis, it is possible to predict the fracture behavior of concrete members.

Keywords: concrete damage plasticity, crack propagation, extended finite element method, fracture mechanics

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Authors: Rezvan Khavari

Abstract:

The Zagros fold-thrust belt in SW Iran is a part of the Alpine-Himalayan system which consists of a variety of structures with different sizes or geometries. The study area is Chamshir Dam, which is located on the Zohreh River, 20 km southeast of Gachsaran City (southwest Iran). The satellite images are valuable means available to geologists for locating geological or geomorphological features expressing regional fault or fracture systems, therefore, the satellite images were used for structural analysis of the Chamshir dam area. As well, using the DEM and geological maps, 3D Models of the area have been constructed. Then, based on these models, all the acquired fracture traces data were integrated in Geographic Information System (GIS) environment by using Arc GIS software. Based on field investigation and DEM model, main structures in the area consist of Cham Shir syncline and two fault sets, the main thrust faults with NW-SE direction and small normal faults in NE-SW direction. There are three joint sets in the study area, both of them (J1 and J3) are the main large fractures around the Chamshir dam. These fractures indeed consist with the normal faults in NE-SW direction. The third joint set in NW-SE is normal to the others. In general, according to topography, geomorphology and structural geology evidences, Chamshir dam has a potential for sliding in some parts of Gachsaran formation.

Keywords: DEM, chamshir dam, zohreh river, satellite images

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Authors: Hossam El-Sayed Emam

Abstract:

As an essential issue for life, water while it’s important for all living organisms. However, the world is dangerously facing the serious problem for the deficiency of the sources of drinking water. Within the aquatic systems, there are various gases, microbes, and other toxic ingredients (chemical compounds and heavy metals) occurred owing to the draining of agricultural and industrial wastewater, resulting in water pollution. On the other hand, fuel (gaseous, liquid, or in solid phase) is one of the extensively consumable energy sources, and owing to its origin from fossil, it contains some sulfur-, nitrogen- and oxygen-based compounds that cause serious problems (toxicity, catalyst poisoning, corrosion, and gum formation andcarcinogenic effects), to be ascribed as undesirable pollutants.MOFs as porous coordinating polymers are superiorly exploited in the adsorption and separationof contaminants for wastewater treatment and fuel purification. The inclusion of highly adsorbent materials like MOFs to be immobilized within cellulosic materialscould be investigated as a new challenge for the separation of contaminants with high efficiency and opportunity for recyclability. Therefore, the current approach ascribes the exploitation of different MOFsimmobilized within cellulose (powder, films, and fabrics)for applications in environmental. Herein, using cellulose containing MOFs in dye removal (degradation and adsorption), pharmaceutical intermediates removal, and fuel purification were summarized.

Keywords: cellulose, MOFs, dye removal, pharmaceutical intermediates, fuel purification

Procedia PDF Downloads 157

Authors: Minho Kwon, Jeonghee Lim, Yeongseok Jeong, Jongyoon Moon, Donghoon Shin, Kiyoung Kim

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In the past, the criteria and procedures for the design of concrete structures were mainly based on the stresses allowed for structural components. However, although the frequency of earthquakes has increased and the risk has increased recently, it has been difficult to determine the safety factor for earthquakes in the safety assessment of structures based on allowable stresses. Recently, limit state design method has been introduced for reinforced concrete structures, and limit state-based approach has been recognized as a more effective technique for seismic design. Therefore, in this study, the limit state of the bridge, which is a structure requiring higher stability against earthquakes, was evaluated. The finite element program LS-DYNA and twenty ground motion were used for time history analysis. The fracture caused by tensile and compression of the pier were set to the limit state. In the concrete tensile fracture, the limit state arrival rate was 100% at peak ground acceleration 0.4g. In the concrete compression fracture, the limit state arrival rate was 100% at peak ground acceleration 0.2g.

Keywords: allowable stress, limit state, safety factor, peak ground acceleration

Procedia PDF Downloads 216

Authors: A. Ghasemipanah, R. Ziaie Moayed, H. Niroumand

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Improving the geotechnical properties of soil has always been one of the issues in geotechnical engineering. Traditional materials have been used to improve and stabilize soils to date, each with its own advantages and disadvantages. Although the soil stabilization by adding materials such as cement, lime, bitumen, etc. is one of the effective methods to improve the geotechnical properties of soil, but nanoparticles are one of the newest additives which can improve the loose soils. This research is intended to study the effect of adding nanobentonite on soil engineering properties, especially the unconfined compression strength and maximum dry unit weight, using clayey soil with low liquid limit (CL) from Kerman (Iran). Nanobentonite was mixed with soil in three different percentages (i.e. 3, 5, 7% by weight of the parent soil) with different curing time (1, 7 and 28 days). The unconfined compression strength, liquid and plastic limits and plasticity index of treated specimens were measured by unconfined compression and Atterberg limits test. It was found that increase in nanobentonite content resulted in increase in the unconfined compression strength, liquid and plastic limits of the clayey soil and reduce in plasticity index.

Keywords: nanobentonite particles, clayey soil, unconfined compression stress, soil improvement.

Procedia PDF Downloads 129