Search results for: mechanical characteristics

Authors: I. Goual, M. S. Goual, M. K. Gueddouda, Taïbi Saïd, Abou-Bekr Nabil, A. Ferhat

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The aim of the paper is to study the hydro-mechanical behavior of a tuff and calcareous sand mixture. A first experimental phase was carried out in order to find the optimal mixture. This showed that the material composed of 80% tuff and 20% calcareous sand provides the maximum mechanical strength. The second experimental phase concerns the study of the drying-wetting behavior of the optimal mixture was carried out on slurry samples and compacted samples at the MPO. Experimental results let to deduce the parameters necessary for the prediction of the hydro-mechanical behavior of pavement formulated from tuff and calcareous sand mixtures, related to moisture. This optimal mixture satisfies the regulation rules and hence constitutes a good local eco-material, abundantly available, for the conception of pavements.

Keywords: tuff, sandy calcareous, road engineering, hydro mechanical behaviour, suction

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Authors: Irena Basaric Ikodinovic, Dragoslav Rakic, Mirjana Vukicevic, Sanja Jockovic, Jovana Jankovic Pantic

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Large long-term settlement occurs at the municipal solid waste landfills over an extended period of time which may lead to breakage of the geomembrane, damage of the cover systems, other protective systems or facilities constructed on top of a landfill. Also, municipal solid waste is an extremely heterogeneous material and its properties vary over location and time within a landfill. These material characteristics require the formulation of a new constitutive model to predict the long-term settlement of municipal solid waste. The paper presents a new constitutive model which is formulated to describe the mechanical behavior of municipal solid waste. Model is based on Modified Cam Clay model and the critical state soil mechanics framework incorporating time-dependent components: mechanical creep and biodegradation of municipal solid waste. The formulated constitutive model is optimized and defined with eight input parameters: five Modified Cam Clay parameters, one parameter for mechanical creep and two parameters for biodegradation of municipal solid waste. Thereafter, the constitutive model is implemented in the software suite for finite element analysis (ABAQUS) and numerical analysis of the experimental landfill settlement is performed. The proposed model predicts the total settlement which is in good agreement with field measured settlement at the experimental landfill.

Keywords: constitutive model, finite element analysis, municipal solid waste, settlement

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Authors: Panyarat Panthong

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This research paper was conducted to examine the association between demographic, professional and social characteristics, and self-leadership of personnel who worked at Sub-District Administrative Organization Offices in Muang District, Udon Thani Province, and to identify the degree level of self-leadership of the selected samples in relation with the study variables. A total of 89 samples were collected from the 15 Sub-District Administrative Organization Offices. The paper employed both quantitative and qualitative methods using the Chi- Square and Cramer’s V statistics for the data analysis. The findings unveiled that constructive thought strategies showed a significant existence followed by behavior- focused strategies and natural reward strategies. Moreover, the research found that the respondents’ length of time working in the position and the respondents’ self- leadership presented a significant association in terms of the behavior-focused and constructive thought strategies. On the other hand, the respondents’ demographic characteristics placed no association with the level of self-leadership in behavior-focused strategies, natural reward strategies and constructive thought strategies. It is hoped that this finding will provide informative and practical guidance for the Ministry of Interior of Thailand and Department of Local Administration of the studied province.

Keywords: demographic characteristics, professional characteristics, self- leadership, social characteristics

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Authors: Gee-Cheol Kim, Joo-Won Kang

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Structural characteristics of spatial structure are different from that of rahmen structures and it has many factors that are unpredictable experientially. Both horizontal and vertical earthquake should be considered because of seismic behaviour characteristics of spatial structures. This experimental study is conducted about seismic response characteristics of roof structure according to the effect of columns or walls, through scale model of arch structure that has the basic dynamic characteristics of spatial structure. Though remarkable response is not occurred for horizontal direction in the region of higher frequency than the region of frequency that seismic energy is concentrated, relatively large response is occurred in vertical direction. It is proved that seismic response of arch structure with column is varied according to property of column.

Keywords: arch structure, seismic response, shaking table, spatial structure

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Authors: Orose Rugchati, Sarawut Wattanawongpitak

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The Chainat 1 variety (CN1) of rice, which generally has high amylose starch, is distributed in the lower part of Northern Thailand. CN1 rice starch can be used in both food and non-food products. In this research, the CN1 rice starch from the wet-milling process was prepared by Pre-Gelatinization (Heat-Moisture Treatments, HMT) under different conditions: percentage of moisture contents (20% and 30%) and duration time in minutes (0, 30, 60, and 90) at a specific temperature 110°C. The physicochemical characteristics of CN1 rice starch modification, such as amylose content, viscosity, swelling, and solubility property, were evaluated and compared with native CN1 rice starch. The results showed that modification CN1 rice starch tends to have some characteristics better than native starch. The appearance color and starch granule of modified CN1 by HMT have more effective characteristics than native starch when increased duration time. The duration time and moisture content are significant factors to the CN1 starch characteristic by HMT. Moreover, physical modification of CN1 starch by HMT can be described as a modified rice starch providing in many applications and the advantage of biodegradability development.

Keywords: physicochemical characteristics, physical modification, pre-gelatinization, Heat-Moisture Treatments, rice starch, Chainat 1 variety (CN1)

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Authors: V. E. Bazhenov, A. V. Li, A. A. Komissarov, A. V. Koltygin, S. A. Tavolzhanskii, O. O. Voropaeva, A. M. Mukhametshina, A. A. Tokar, V. A. Bautin

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Magnesium-based alloys are considered as effective materials in the development of biodegradable implants. The magnesium alloys containing Mg, Zn, Ca as an alloying element are the subject of the particular interest. These elements are the nutrients for the human body, which provide their high biocompatibility. In this work, we investigated the effect of severe plastic deformation (SPD) on the mechanical and corrosion properties of Mg-Zn-Ca and Mg-Zn-Ca-Mn alloys containing from 2 to 4 wt.% Zn; 0.7 wt.% Ca and up to 1 wt.% Mn. Hot extrusion was used as a method of intensive plastic deformation. The temperature of hot extrusion was set to 220 °C and 300 °C. Metallographic analysis after hot extrusion shows that the grain size in the studied alloys depends on the deformation temperature. The grain size for all of investigated alloys is in the range from 3 to 7 microns, and 3 μm corresponds to the extrusion temperature of 220 °C. Analysis of mechanical properties after extrusion shows that extrusion at a temperature of 220 °C and alloying with Mn increase the strength characteristics and decrease the ductility of studied alloys. A slight anisotropy of properties in the longitudinal and transverse directions was also observed. Measurements of corrosion properties revealed that the addition of Mn to Mg-Zn-Ca alloys reduces the corrosion rate. On the other hand, increasing the Zn content in alloys increases the corrosion rate. The extrusion temperature practically does not affect the corrosion rate. Acknowledgement: The authors gratefully acknowledge the financial support of the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST «MISiS» (No K2-2019-008), implemented by a governmental decree dated 16th of March 2013, N 211.

Keywords: biocompatibility, hot extrusion, magnesium alloys, severe plastic deformation, properties

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Authors: Itumeleng Phage

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Students’ comprehension of graphs may be affected by the characteristics of the discipline in which the graph is used, the type of the task as well as the background of the students who are the readers or interpreters of the graph. This research study investigated these aspects of the graph comprehension of 152 first-year undergraduate physics students by comparing their responses to corresponding tasks in the mathematics and physics disciplines. The discipline characteristics were analysed for four task-related constructs namely coordinates, representations, area and slope. Students’ responses to corresponding visual decoding and judgement tasks set in mathematics and kinematics contexts were statistically compared. The effects of the participants’ gender, year of school completion and study course were determined as reader characteristics. The results of the empirical study indicated that participants generally transferred their mathematics knowledge on coordinates and representation of straight line graphs to the physics contexts, but not in the cases of parabolic and hyperbolic functions or area under graphs. Insufficient understanding of the slope concept contributed to weak performances on this construct in both mathematics and physics contexts. Discipline characteristics seem to play a vital role in students’ understanding, while reader characteristics had insignificant to medium effects on their responses.

Keywords: kinematics graph, discipline characteristics, constructs, coordinates, representations, area and slope

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Authors: Zhang Yu

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Shanxi Province is a province with a long history in China. The historical characteristics of Jinzhong Prefecture in Shaanxi Province are very prominent. This research has done a lot of field research and analysis, and has analyzed a large number of documents. The formation and characteristics of villages in Jinzhong Prefecture are summarized. But the remains of many areas have not been systematically discovered and analyzed. This study found that the reasons for the formation of villages are natural, cultural, traffic and economic reasons. It mainly includes water, mountain, and developed business culture during the Ming and Qing Dynasties. By analyzing the evolution characteristics of each period, the characteristics and remains of the existing villages are explained in detail. These types of relics mainly include courtyards, fortresses, and Exchange shops. This study can provide systematic guidance on the protection of future village remains.

Keywords: Jinzhong Prefecture, village, features, remains

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Authors: Siri Marthe Arbo, Afaf Saai, Sture Sørli, Mette Nedreberg

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This work aims to establish a reliable approach for optimizing a Laser Metal Deposition (LMD) process for a critical maritime component, based on the material properties and structural performance required by the maritime industry. The component of interest is a water jet impeller, for which specific requirements for material properties are defined. The developed approach is based on the assessment of the effects of LMD process parameters on microstructure and material performance of standard AM 2205 duplex stainless steel powder. Duplex stainless steel offers attractive properties for maritime applications, combining high strength, enhanced ductility and excellent corrosion resistance due to the specific amounts of ferrite and austenite. These properties are strongly affected by the microstructural characteristics in addition to microstructural defects such as porosity and welding defects, all strongly influenced by the chosen LMD process parameters. In this study, the influence of deposition speed and heat input was evaluated. First, the influences of deposition speed and heat input on the microstructure characteristics, including ferrite/austenite fraction, amount of porosity and welding defects, were evaluated. Then, the achieved mechanical properties were evaluated by standard testing methods, measuring the hardness, tensile strength and elongation, bending force and impact energy. The measured properties were compared to the requirements of the water jet impeller. The results show that the required amounts of ferrite and austenite can be achieved directly by the LMD process without post-weld heat treatments. No intermetallic phases were observed in the material produced by the investigated process parameters. A high deposition speed was found to reduce the ductility due to the formation of welding defects. An increased heat input was associated with reduced strength due to the coarsening of the ferrite/austenite microstructure. The microstructure characterizations and measured mechanical performance demonstrate the great potential of the LMD process and generate a valuable database for the optimization of the LMD process for duplex stainless steels.

Keywords: duplex stainless steel, laser metal deposition, process optimization, microstructure, mechanical properties

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Authors: Danuvasin Charoen

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Online romance scams are conducted by criminals using social networks and dating sites. These criminals use love to deceive the victims to send them money. The victims not only lose money to the criminals, but they are also heartbroken. This study investigates how online romance scams work and why people become victims to them. The researcher also identifies the characteristics of the perpetrators and victims. The data were collected from in-depth interviews with former victims and police officers responsible for the cases. By studying the methods and characteristics of the online romance scam, we can develop effective methods and policies to reduce the rates of such crimes.

Keywords: romance scam, online scam, phishing, cybercrime

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Authors: Sepehr Moradi

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The physical and mechanical property parameters, inter-relation of key dimensional and distribution profile of raw Australia Superfine Merino Wool (ASFW) and Inner Mongolia Cashmere (IMC) fibres have been studied. The relationship between the properties of these fibres is assessed using fit transformation functions obtained through correlation coefficient analysis. ASFW and IMC fibre properties are found to be both positively skewed and asymmetric in nature. Whilst fibre diameter varies along its length and both ends have a tapering shape. The basic physical features, namely linear density, true local diameter, true length and breaking load are positively correlated while their tenacity is negatively correlated. The tenacity and true length follow a second order polynomial while the true local diameter is linearly correlated. Assessment of the diameter and length is sufficient to estimate the evaluation of quality for commercial grade ASFW and IMC fibres.

Keywords: Australia Superfine Merino Wool fibre, Inner Mongolia Cashmere fibre, distribution profile, physical properties

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Authors: Abdelrahman Alghazali, Youssef Kassem, Hüseyin Çamur, Ozan Erenay

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Savonius is a drag type vertical axis wind turbine. Savonius wind turbines have a low cut-in speed and can operate at low wind speed. This makes it suitable for electricity or mechanical generation in low-power applications such as individual domestic installations. Therefore, the primary purpose of this work was to investigate the relationship between the type of Savonius rotor and the torque and mechanical power generated. And it was to illustrate how the type of rotor might play an important role in the prediction of mechanical power of wind turbine powered car. The main purpose of this paper is to predict and investigate the aerodynamic effects by means of velocity analysis on the performance of a wind turbine powered car by converting the wind energy into mechanical energy to overcome load that rotates the main shaft. The predicted results based on theoretical analysis were compared with experimental results obtained from literature. The percentage of error between the two was approximately around 20%. Prediction of the torque was done at a wind speed of 4 m/s, and an angular velocity of 130 RPM according to meteorological statistics in Northern Cyprus.

Keywords: mechanical power, torque, Savonius rotor, wind car

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Authors: Moez Selmi, Mariem Kacem, Mehrez Jamei, Philippe Dubujet

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Earth pressure balance (EPB) tunnel boring machines are designed for digging in different types of soil, especially clay soils. This operation requires the treatment of soil by lubricants to facilitate the procedure of excavation. A possible use of this soil is limited by the effect of treatment on the hydro-mechanical properties of the soil. This work aims to study the effect of a foaming agent on the hydro-mechanical properties of clay soil. The injection of the foam agent in the soil leads to create a soil matrix in which they are incorporated gas bubbles. The state of the foam in the soil is scalable thanks to the degradation of the gas bubbles in the soil.

Keywords: EPB, clay soils, foam agent, hydro-mechanical properties, degradation

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Authors: Hafiz Haseeb Nisar, Maryam Bilal

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This qualitative study was conducted to investigate the underlying dynamics, key success factors and characteristics of Pakistani business leaders. The sample included 5 top businessmen from different business sectors. They were approached through the magazine “Manager Today” office in Lahore. Semi-structured interview technique was used to understand their experiences, attitudes, styles of management and key factors in their business success. Grounded theory was employed to analyze data. The following themes emerged as characteristics of business leaders: optimism, assertiveness, professionalism, effective management style, business knowledge/ excellence, supportive family and strong faith in God. It was noted that all these were interlinked, which leads the businessmen to become a successful business tycoon of this country. The importance of this study rests in its eastern contribution to the theoretical framework of the psychology of business leaders and particularly these findings will help to realize the basic key factors of success behind a business leader in Pakistan.

Keywords: business psychology, characteristics, key personality factors, leadership

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Authors: Miron A, Tadmor R, Pinkert S

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Soil contamination is a pressing environmental concern, drawing considerable focus due to its adverse ecological and health outcomes, and the frequent occurrence of contamination incidents in recent years. The interaction between the oil pollutant and the host soil can alter the mechanical properties of the soil in a manner that can crucially affect engineering challenges associated with the stability of soil systems. The geotechnical investigation of contaminated soils has gained momentum since the Gulf War in the 1990s, when a massive amount of oil was spilled into the ocean. Over recent years, various types of soil contaminations have been studied to understand the impact of pollution type, uncovering the mechanical complexity that arises not just from the pollutant type but also from the properties of the host soil and the interplay between them. This complexity is associated with diametrically opposite effects in different soil types. For instance, while certain oils may enhance the frictional properties of cohesive soils, they can reduce the friction in granular soils. This striking difference can be attributed to the different mechanisms at play: physico-chemical interactions predominate in the former case, whereas lubrication effects are more significant in the latter. this study introduces an empirical law designed to quantify the mechanical effect of oil contamination in granular soils, factoring the properties of both the contaminating oil and the host soil. This law is achieved by comprehensive experimental research that spans a wide array of oil types and soils with unique configurations and morphologies. By integrating these diverse data points, our law facilitates accurate predictions of how oil contamination modifies the frictional characteristics of general granular soils.

Keywords: contaminated soils, lubrication, friction, granular media

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Authors: Serap Durkut, A. Eser Elcin, Y. Murat Elcin

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Stimuli-sensitive polymeric hydrogels have received extensive attention in the biomedical field due to their sensitivity to physical and chemical stimuli (temperature, pH, ionic strength, light, etc.). This study describes the rheological properties of a novel thermoresponsive poly(N-vinylcaprolactam)-g-collagen hydrogel. In the study, we first synthesized a facile and novel synthetic carboxyl group-terminated thermo-responsive poly(N-vinylcaprolactam)-COOH (PNVCL-COOH) via free radical polymerization. Further, this compound was effectively grafted with native collagen, by utilizing the covalent bond between the carboxylic acid groups at the end of the chains and amine groups of the collagen using cross-linking agent (EDC/NHS), forming PNVCL-g-Col. Newly-formed hybrid hydrogel displayed novel properties, such as increased mechanical strength and thermoresponsive characteristics. PNVCL-g-Col showed low critical solution temperature (LCST) at 38ºC, which is very close to the body temperature. Rheological studies determine structural–mechanical properties of the materials and serve as a valuable tool for characterizing. The rheological properties of hydrogels are described in terms of two dynamic mechanical properties: the elastic modulus G′ (also known as dynamic rigidity) representing the reversible stored energy of the system, and the viscous modulus G″, representing the irreversible energy loss. In order to characterize the PNVCL-g-Col, the rheological properties were measured in terms of the function of temperature and time during phase transition. Below the LCST, favorable interactions allowed the dissolution of the polymer in water via hydrogen bonding. At temperatures above the LCST, PNVCL molecules within PNVCL-g-Col aggregated due to dehydration, causing the hydrogel structure to become dense. When the temperature reached ~36ºC, both the G′ and G″ values crossed over. This indicates that PNVCL-g-Col underwent a sol-gel transition, forming an elastic network. Following temperature plateau at 38ºC, near human body temperature the sample displayed stable elastic network characteristics. The G′ and G″ values of the PNVCL-g-Col solutions sharply increased at 6-9 minute interval, due to rapid transformation into gel-like state and formation of elastic networks. Copolymerization with collagen leads to an increase in G′, as collagen structure contains a flexible polymer chain, which bestows its elastic properties. Elasticity of the proposed structure correlates with the number of intermolecular cross-links in the hydrogel network, increasing viscosity. However, at 8 minutes, G′ and G″ values sharply decreased for pure collagen solutions due to the decomposition of the elastic and viscose network. Complex viscosity is related to the mechanical performance and resistance opposing deformation of the hydrogel. Complex viscosity of PNVCL-g-Col hydrogel was drastically changed with temperature and the mechanical performance of PNVCL-g-Col hydrogel network increased, exhibiting lesser deformation. Rheological assessment of the novel thermo-responsive PNVCL-g-Col hydrogel, exhibited that the network has stronger mechanical properties due to both permanent stable covalent bonds and physical interactions, such as hydrogen- and hydrophobic bonds depending on temperature.

Keywords: poly(N-vinylcaprolactam)-g-collagen, thermoresponsive polymer, rheology, elastic modulus, stimuli-sensitive

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Authors: Venkatesan Sundaramoorthy

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The field of ceramics has undergone a remarkable transformation with the advent of additive manufacturing technologies. This comprehensive review explores the mechanical properties of additively manufactured ceramic components, focusing on key materials such as Alumina, Zirconia, and Silicon Carbide. The study delves into various authors' review technology into the various additive manufacturing techniques, including Stereolithography, Powder Bed Fusion, and Binder Jetting, highlighting their advantages and challenges. It provides a detailed analysis of the mechanical properties of these ceramics, offering insights into their hardness, strength, fracture toughness, and thermal conductivity. Factors affecting mechanical properties, such as microstructure and post-processing, are thoroughly examined. Recent advancements and future directions in 3D-printed ceramics are discussed, showcasing the potential for further optimization and innovation. This review underscores the profound implications of additive manufacturing for ceramics in industries such as aerospace, healthcare, and electronics, ushering in a new era of engineering and design possibilities for ceramic components.

Keywords: mechanical properties, additive manufacturing, ceramic materials, PBF

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Authors: Hsien Hao Teng

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This study uses numerical simulation to analyze the aerodynamic characteristics of the 53-degree Lambda wing with a sweep angle and mainly discusses the numerical simulation results and physical characteristics of the wall y+. Use the commercial software Fluent to execute Mach number 0.15; when the angle of attack attitude is between 0 degrees and 27 degrees, the physical characteristics of the overall aerodynamic force are analyzed, especially when the fluid separation and vortex structure changes are discussed under the condition of high angle of attack, it will affect The instability of pitching moment. In the numerical calculation, the use of wall y+ and turbulence model will affect the prediction of vortex generation and the difference in structure. The analysis results are compared with experimental data to discuss the trend of the aerodynamic characteristics of the Lambda wing.

Keywords: lambda wing, wall function, turbulence model, computational fluid dynamics

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Authors: Chang Soo Chon, Cheol Woong Ko, Han Sung Kim

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The aim of this study is to develop an anterior lumbar interbody fusion (ALIF) PEEK cage suitable for Korean people. In this study, CT images were obtained from Korean male (173cm, 71kg) and 3D Korean lumbar models were reconstructed based on the CT images to investigate anatomical characteristics. Major design parameters of anterior lumbar interbody fusion (ALIF) PEEK Cage were selected using the morphological measurement information of the Korean Lumbar models. Through finite element analysis and mechanical tests, the developed ALIF PEEK Cage prototype was compared with the Fidji Cage (Zimmer.Inc, USA) and it was found that the ALIF prototype showed similar and/or superior mechanical performance compared to the FidJi Cage. Also, clinical validation for the ALIF PEEK Cage prototype was carried out to check predictable troubles in surgical operations. Finally, it is considered that the convenience and stability of the prototype was clinically verified.

Keywords: inter-body anterior fusion, ALIF cage, PEEK, Korean lumbar, CT image, animal test

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Authors: Dilay Akgun Giray

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Basic insuffiency spaces of ASD diagnosed individuals can be grouped as cognitive and academic characteristics, communicational characteristics, social characteristics and emotional characteristics. Referring to the features that children with ASD exhibit on social events, it is clear they have limitations for several social skills. One of the evidence based practices which has been developed and used for the limitations of definite social skills for individuals with autism is “Social Story Method”. Social stories was designed and applied for the first time in 1991, a special education teacher, in order to acquire social skills and improve the existing social skills for children with ASD. Many studies have revealed the effectiveness of social stories for teaching the social skills to individuals with ASD. In this study, three social skills that the child ,who was diagnosed ASD, is going to need primarily will be studied with smart board. This study is multiple probe across-behavior design which is one of the single subject research models.

Keywords: authism spectrum disorders, social skills, social story, smart board

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Authors: Mochamad Chalid, Imam Prabowo

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The pollution due to non-degradable material such as plastics, has led to studies about the development of environmental-friendly material. Because of biodegradability obtained from natural sources, polylactid acid (PLA) and ijuk fiber are interesting to modify into a composite. This material is also expected to reduce the impact of environmental pollution. Surface modification of ijuk fiber through alkalinization with 0.25 M NaOH solution for 30 minutes, was aimed to enhance it’s compatibility to PLA, in order to improve properties of the composite such as the mechanical properties. Alkalinization of the ijuk fibers annihilates some surface components such as lignin, wax and hemicelloluse, so the pore on the surface clearly appeared, decreasing of the density and diameter of the ijuk fibers. The change of the ijuk fiber properties leads to increase the mechanical properties of PLA composites reinforced the ijuk fibers through strengthening of the mechanical interlocking with the PLA matrix. An addition to enhance the distribution of the fibers in the PLA matrix, the stirring during DCM solvent evaporation from the mixture of the ijuk fibers and the dissolved-PLA can reduce amount of the trapped-voids and fibers pull-out phenomena, which can decrease the mechanical properties of the composite.

Keywords: polylactic acid, Arenga pinnata, alkalinization, compatibility, adhesion, morphology, mechanical properties, volume fraction, distributiom

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Authors: O. Khalaj, B. Mašek, H. Jirková, J. Svoboda

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By using a combination of new technologies together with an unconventional use of different types of materials, specific mechanical properties and structures of the material can be achieved. Some possibilities are enabled by a combination of powder metallurgy in the preparation of a metal matrix with dispersed stable particles achieved by mechanical alloying and hot consolidation. This paper explains the thermomechanical properties of new generation of Oxide Dispersion Strengthened alloys (ODS) within three ranges of temperature with specified deformation profiles. The results show that the mechanical properties of new ODS alloys are significantly affected by the thermomechanical treatment.

Keywords: hot forming, ODS, alloys, thermomechanical, Fe-Al, Al2O3

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Authors: Solomon Tilahun Desisa, Muktar Seid Hussen

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Hibiscus macranthus is one of family Malvaceae and genus Hibiscus plant which grows mainly in western part of Ethiopia. Hibiscus macranthus is the most adaptable and abundant plant in the nation, which are used as an ornamental plant often a hedge or fence plant, and used as a firewood after harvesting the stem together with the bark, and used also as a fiber for trying different kinds of things by forming the rope. However, Hibiscus macranthus plant fibre has not been commercially exploited and extracted properly. This study of work describes the possibility of mechanical and retting methods of Hibiscus macranthus fibre extraction and characterization. Hibiscus macranthus fibre is a bast fibre which obtained naturally from the stem or stalks of the dicotyledonous plant since it is a natural cellulose plant fiber. And the fibre characterized by studying its physical and chemical properties. The physical characteristics were investigated as follows, including the length of 100-190mm, fineness of 1.0-1.2Tex, diameter under X100 microscopic view 16-21 microns, the moisture content of 12.46% and dry tenacity of 48-57cN/Tex along with breaking extension of 0.9-1.6%. Hibiscus macranthus fiber productivity was observed that 12-18% of the stem out of which more than 65% is primary long fibers. The fiber separation methods prove to decrease of non-cellulose ingredients in the order of mechanical, water and chemical methods. The color measurement also shows the raw Hibiscus macranthus fiber has a natural golden color according to YID1925 and paler look under both retting methods than mechanical separation. Finally, it is suggested that Hibiscus macranthus fibre can be used for manufacturing of natural and organic crop and coffee packages as well as super absorbent, fine and high tenacity textile products.

Keywords: Hibiscus macranthus, bast fiber, extraction, characterization

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Authors: D. Remache, M. Semaan, C. Baron, M. Pithioux, P. Chabrand, J. M. Rossi, J. L. Milan

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A good understanding of the mechanical properties of the bone implies a better understanding of its various diseases, such as osteoporosis. Berkovich nanoindentation tests were performed on the human cortical bone to extract its orthotropic parameters. The nanoindentation experiments were then simulated by the finite element method. Different configurations of interactions between the tip indenter and the bone were simulated. The orthotropic parameters of the material were identified by the inverse method for each configuration. The friction effect on the bone mechanical properties was then discussed. It was found that the inverse method using the finite element method is a very efficient method to predict the mechanical behavior of the bone.

Keywords: mechanical behavior of bone, nanoindentation, finite element analysis, inverse optimization approaches

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Authors: Malek Ali

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Composites materials of Poly (vinyl alcohol) (PVA)/Chitosan (CS) have been synthesized and characterized successfully. HNTs have been added to composites to enhance the mechanical and degradation properties by hydrogen bonding interactions, compatibility, and chemical crosslink between HNTs and PVA. PVA/CS/HNTs composites prepared with different concentration ratio. SEM micrographs of composites surface showed that more agglomeration with more chitosan ratio. Mechanical and degradation properties were characterized and the result indicates that Mechanical and degradation of 80%PVA/5%Chitosan/15%HNTs higher than the others PVA/CS/HNTs composites.

Keywords: PVA/chitosan, composites, PVA/CS/HNTs, HNTs

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Authors: Mitsuhiro Okayasu

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To better understand the lattice characteristics of lead zirconate titanate (PZT) ceramics, the lattice orientations and domain-switching characteristics have been directly examined during loading and unloading using various experimental techniques. Upon loading, the PZT ceramics are fractured linear and nonlinearly during the compressive loading process. The strain characteristics of the PZT ceramic were directly affected by both the lattice and domain switching strain. Due to the piezoelectric ceramic, electrical activity of lightning-like behavior occurs in the PZT ceramics, which attributed to the severe domain-switching leading to weak piezoelectric property. The characteristics of domain-switching and reverse switching are detected during the loading and unloading processes. The amount of domain-switching depends on the grain, due to different stress levels. In addition, two patterns of 90˚ domain-switching systems are characterized, namely (i) 90˚ turn about the tetragonal c-axis and (ii) 90˚ rotation of the tetragonal a-axis. In this case, PZT ceramic was loaded by the thermal stress at 80°C. Extent of domain switching is related to the direction of c-axis of the tetragonal structure, e.g., that axis, orientated close to the loading direction, makes severe domain switching. It is considered that there is 90˚ domain switching, but in actual, the angle of domain switching is less than 90˚, e.g., 85.4° ~ 90.0°. In situ TEM observation of the domain switching characteristics of PZT ceramic has been conducted with increasing the sample temperature from 25°C to 300°C, and the domain switching like behavior is directly observed from the lattice image, where the severe domain switching occurs less than 100°C.

Keywords: PZT, lead zirconate titanate, piezoelectric ceramic, domain switching, material property

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Authors: Maruf Yinka Kolawole, Jacob Olayiwola Aweda, Farasat Iqbal, Asif Ali, Sulaiman Abdulkareem

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Zinc is a non-ferrous metal with potential application in orthopaedic implant materials. However, its poor mechanical properties were major challenge to its application. Therefore, this paper studies the mechanical properties of biodegradable Zn-based alloy for biomedical application. Pure zinc powder with varying (0, 1, 2, 3 & 6) wt% of magnesium powders were ball milled using ball-to-powder ratio (B:P) of 10:1 at 350 rpm for 4 hours. The resulting milled powders were compacted and sintered at 300 MPa and 350 °C respectively. Microstructural, phase and mechanical properties analyses were performed following American standard of testing and measurement. The results show that magnesium has influence on the mechanical properties of zinc. The compressive strength, hardness and elastic modulus of 210 ± 8.878 MPa, 76 ± 5.707 HV and 45 ± 11.616 GPa respectively as obtained in Zn-2Mg alloy were optimum and meet the minimum requirement of biodegradable metal for orthopaedics application. These results indicate an increase of 111, 93 and 93% in compressive strength, hardness and elastic modulus respectively as compared to pure zinc. The increase in mechanical properties was adduced to effectiveness of compaction pressure and intermetallic phase formation within the matrix resulting in high dislocation density for improving strength. The study concluded that, Zn-2Mg alloy with optimum mechanical properties can therefore be considered a potential candidate for orthopaedic application.

Keywords: Biodegradable metal, Biomedical application, Mechanical properties, Powder Metallurgy, Zinc

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Authors: Peng Hao Wang, Ronald Sterkenburg, Garam Kim, Yuwei He

Abstract:

As composite materials continue to gain popularity in the aerospace industry; large airframe sections made out of composite materials are becoming the standard for aerospace manufacturers. However, the heavy utilization of these composite materials also increases the importance of the recycling of these composite materials. A team of Purdue University School of Aviation and Transportation Technology (SATT) faculty and students have partnered to investigate the characteristics of 3D printed recycled carbon fiber. A prototype of a 3D printed recycled carbon fiber part was provided by an industry partner and different sections of the prototype were used to create specimens. A furnace was utilized in order to remove the polymer from the specimens and the specimen’s fiber content and fiber length was calculated from the remaining fibers. A differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) test was also conducted on the 3D printed recycled carbon fiber prototype in order to determine the prototype’s degree of cure at different locations. The data collected from this study provided valuable information in the process improvement and understanding of 3D printed recycled carbon fiber.

Keywords: 3D printed, carbon fiber, fiber content, recycling

Procedia PDF Downloads 152

Authors: Abriak Yassine, Zri Abdeljalil, Benzerzour Mahfoud., Hadj Sadok Rachid, Abriak Nor-Edine

Abstract:

In this study, firstly, the study of the capacity reuse of dredged sediments and treated sediments with lime or cement were used in an establishment layer and the base layer of the roadway. Also, the analysis of mineral changes caused by the addition of lime or cement on the way as described in the mechanical results of stabilised sediments. After determining the quantity of lime and cement required to stabilise the sediment, the compaction characteristics were studied using the modified Proctor method. Then the evolution of the three parameters, that is, ideal water content and maximum dry density had been determined. Mechanical exhibitions can be assessed across the resistance to compression, flexibility modulus and the resistance under traction. The resistance of the formulation treated with cement addition (ROLAC®645) increase with the quantity of ROLAC®645. Traction resistances and the elastic modulus were utilized to assess the potential of the formulation as road construction materials utilizing classification diagram. The results show the various formulations with ROLAC® 645may be employed in subgrades and foundation layers for roads.

Keywords: cement, dredged, sediment, foundation layer, resistance

Procedia PDF Downloads 67

Authors: L. Kučerová, M. Bystrianský, V. Kotěšovec

Abstract:

Thermo-mechanical processing with various processing parameters was applied to 0.2%C-0.6%Mn-2S%i-0.8%Cr low alloyed high strength steel. The aim of the processing was to achieve the microstructures typical for transformation induced plasticity (TRIP) steels. Thermo-mechanical processing used in this work incorporated two or three deformation steps. The deformations were in all the cases carried out during the cooling from soaking temperatures to various bainite hold temperatures. In this way, 4-10% of retained austenite were retained in the final microstructures, consisting further of ferrite, bainite, martensite and pearlite. The complex character of TRIP steel microstructure is responsible for its good strength and ductility. The strengths achieved in this work were in the range of 740 MPa – 836 MPa with ductility A_5mm of 31-41%.

Keywords: pearlite, retained austenite, thermo-mechanical treatment, TRIP steel

Procedia PDF Downloads 265