Search results for: advanced high strength steel

Authors: Huseyin Zengin, Muhammet Emre Turan, Yunus Turen, Hayrettin Ahlatci, Yavuz Sun

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This study aimed for understanding the effects of dilute Nb additions on the austenite microstructure of microalloyed steels at five different reheating temperatures from 950 °C to 1300 °C. Four microalloyed high-carbon steels having 0.8 %wt C were examined in which three of them had varying Nb concentrations from 0.005 wt% to 0.02 wt% and one of them had no Nb concentration. The quantitative metallographic techniques were used to measure the average prior austenite grain size in order to compare the grain growth pinning effects of Nb precipitates as a function of reheating temperature. Due to the higher stability of the precipitates with increasing Nb concentrations, the grain coarsening temperature that resulted in inefficient grain growth impediment and a bimodal grain distribution in the microstructure, showed an increase with increasing Nb concentration. The respective grain coarsening temperatures (T_GC) in an ascending order for the steels having 0.005 wt% Nb, 0.01 wt% Nb and 0.02 wt% Nb were 950 °C, 1050 °C and 1150 °C. According to these observed grain coarsening temperatures, an approximation was made considering the complete dissolution temperature (T_DISS) of second phase particles as T_GC=T_DISS-300. On the other hand, the plain carbon steel did not show abnormal grain growth behaviour due to the absence of second phase particles. It was also observed that the higher the Nb concentration, the smaller the average prior austenite grain size although the small increments in Nb concenration did not change the average grain size considerably.

Keywords: microalloyed steels, prior austenite grains, second phase particles, grain coarsening temperature

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Authors: Loha Hashimy, Isabella Castillo

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In today's rapidly evolving technological landscape, the importance of precise navigation and mapping systems cannot be understated. As various sectors undergo transformative changes, the market potential for Advanced Mapping and Management Systems (AMMS) emerges as a critical focus area. The Galileo/GNSS-Based Autonomous Mobile Mapping System (GAMMS) project, specifically targeted toward high-definition mapping (HDM), endeavours to provide insights into this market within the broader context of the geomatics and navigation fields. With the growing integration of Autonomous Vehicles (AVs) into our transportation systems, the relevance and demand for sophisticated mapping solutions like HDM have become increasingly pertinent. The research employed a meticulous, lean, stepwise, and interconnected methodology to ensure a comprehensive assessment. Beginning with the identification of pivotal project results, the study progressed into a systematic market screening. This was complemented by an exhaustive desk research phase that delved into existing literature, data, and trends. To ensure the holistic validity of the findings, extensive consultations were conducted. Academia and industry experts provided invaluable insights through interviews, questionnaires, and surveys. This multi-faceted approach facilitated a layered analysis, juxtaposing secondary data with primary inputs, ensuring that the conclusions were both accurate and actionable. Our investigation unearthed a plethora of drivers steering the HD maps landscape. These ranged from technological leaps, nuanced market demands, and influential economic factors to overarching socio-political shifts. The meteoric rise of Autonomous Vehicles (AVs) and the shift towards app-based transportation solutions, such as Uber, stood out as significant market pull factors. A nuanced PESTEL analysis further enriched our understanding, shedding light on political, economic, social, technological, environmental, and legal facets influencing the HD maps market trajectory. Simultaneously, potential roadblocks were identified. Notable among these were barriers related to high initial costs, concerns around data quality, and the challenges posed by a fragmented and evolving regulatory landscape. The GAMMS project serves as a beacon, illuminating the vast opportunities that lie ahead for the HD mapping sector. It underscores the indispensable role of HDM in enhancing navigation, ensuring safety, and providing pinpoint, accurate location services. As our world becomes more interconnected and reliant on technology, HD maps emerge as a linchpin, bridging gaps and enabling seamless experiences. The research findings accentuate the imperative for stakeholders across industries to recognize and harness the potential of HD mapping, especially as we stand on the cusp of a transportation revolution heralded by Autonomous Vehicles and advanced geomatic solutions.

Keywords: high-definition mapping (HDM), autonomous vehicles, PESTEL analysis, market drivers

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Authors: Lamaa Sellami, Bechir Alaya

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Nowadays, video-on-demand (VoD) applications are becoming one of the tendencies driving vehicular network users. In this paper, considering the unpredictable vehicle density, the unexpected acceleration or deceleration of the different cars included in the vehicular traffic load, and the limited radio range of the employed communication scheme, we introduce the “Dynamic Vehicular Clustering” (DVC) algorithm as a new scheme for video streaming systems over VANET. The proposed algorithm takes advantage of the concept of small cells and the introduction of wireless backhauls, inspired by the different features and the performance of the Long Term Evolution (LTE)- Advanced network. The proposed clustering algorithm considers multiple characteristics such as the vehicle’s position and acceleration to reduce latency and packet loss. Therefore, each cluster is counted as a small cell containing vehicular nodes and an access point that is elected regarding some particular specifications.

Keywords: video-on-demand, vehicular ad-hoc network, mobility, vehicular traffic load, small cell, wireless backhaul, LTE-advanced, latency, packet loss

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Authors: S. J. Shahidzadeh Tabatabaei, A. M. Fattahi

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Modal analysis of an FGM plate containing the ceramic phase of Al2O3 and metal phase of stainless steel 304 was performed using ABAQUS, with the assumptions that the material has an elastic mechanical behavior and its Young modulus and density are varying in thickness direction. For this purpose, a subroutine was written in FORTRAN and linked with ABAQUS. First, a simulation was performed in accordance to other researcher’s model, and then after comparing the obtained results, the accuracy of the present study was verified. The obtained results for natural frequency and mode shapes indicate good performance of user-written subroutine as well as FEM model used in present study. After verification of obtained results, the effect of clamping condition and the material type (i.e. the parameter n) was investigated. In this respect, finite element analysis was carried out in fully clamped condition for different values of n. The results indicate that the natural frequency decreases with increase of n, since with increase of n, the amount of ceramic phase in FGM plate decreases, while the amount of metal phase increases, leading to decrease of the plate stiffness and hence, natural frequency, as the Young modulus of Al2O3 is equal to 380 GPa and the Young modulus of stainless steel 304 is equal to 207 GPa.

Keywords: FGM plates, modal analysis, natural frequency, finite element method

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Authors: Bardia Khafaf, Mehrdad Ghaffari, Amir Hussein Samakar

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It is currently desirable to use Hollow Square Sections (HSS) in moment resistant structures in construction of building because they offer fewer restrictions for designing and more useful space while adhering to build design codes. This paper present a through bolt connection in HSS column. This connection meets building code standards that require the moment resistant connections to deflect and absorb energy resulting from gravity and seismic loads. Connection through bolts is installed and pretension to provide the connection strength needed to make a beam–column moment rigid zone. A rigid joint is typically used to resist lateral forces by holding columns and beams fixed in relation to one another. With bolted moment frames using HSS columns, a through–bolt connection could be used to secure the beam and end plate to the column. However, when multiple columns and beams are used to span a length of building, the use of through-bolts would necessities aligning multiple beams simultaneously to the columns. In the case of a linear span, the assembly process requires the holes of a first beam end plate to be aligned with through bolt holes in a column and aligning the holes of a second, opposing beam plate with the column through bolt, then inserting the through bolts in each hole for tightening with nuts and washers. In moment resistant building, a problem arises when assembling beams to columns where multiple beams and columns are required. Through bolt, moment connections are among the economical, practical and not difficult rigid steel connection for HSS column building. In this paper, the results of numerous analytical studies performed for moment structures with HSS columns with through bolt based on AISC standard codes are shown.

Keywords: through bolt, moment resistant connection, HSS columns section, construction engineering

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Authors: A. Khalina, K. Shaharuddin, M. S. Wahab, M. P. Saiman, H. A. Aisyah

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This paper investigates the effect of alkali treatment and mechanical properties of kenaf (Hibiscus cannabinus) fibre for the development of yarn. Two different fibre sources are used for the yarn production. Kenaf fibres were treated with sodium hydroxide (NaOH) in the concentration of 3, 6, 9, and 12% prior to fibre opening process and tested for their tensile strength and Young’s modulus. Then, the selected fibres were introduced to fibre opener at three different opening processing parameters; namely, speed of roller feeder, small drum, and big drum. The diameter size, surface morphology, and fibre durability towards machine of the fibres were characterized. The results show that concentrations of NaOH used have greater effects on fibre mechanical properties. From this study, the tensile and modulus properties of the treated fibres for both types have improved significantly as compared to untreated fibres, especially at the optimum level of 6% NaOH. It is also interesting to highlight that 6% NaOH is the optimum concentration for the alkaline treatment. The untreated and treated fibres at 6% NaOH were then introduced to fibre opener, and it was found that the treated fibre produced higher fibre diameter with better surface morphology compared to the untreated fibre. Higher speed parameter during opening was found to produce higher yield of opened-kenaf fibres.

Keywords: alkaline treatment, kenaf fibre, tensile strength, yarn production

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Authors: C. H. Jeon, Y. H. Kim, G. A. Lee

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Reducing resource consumption and carbon dioxide emission are recognized as urgent issues. One way of resolving these issues is to reduce product weight. Magnesium alloys are considered promising candidates because of their lightness. Various studies have been conducted on using magnesium alloy instead of conventional iron or aluminum in mechanical parts, due to the light weight and superior specific strength of magnesium alloy. However, even stronger magnesium alloys are needed for mechanical parts. One common way to enhance the strength of magnesium alloy is by extruding the ingot. In order to enhance the mechanical properties, magnesium alloy ingot were extruded at various extrusion ratios. Relationship between extrusion ratio and mechanical properties was examined on extruded material of magnesium alloy. And Textures and microstructures of the extruded materials were investigated.

Keywords: extrusion, extrusion ratio, magnesium, mechanical property, lightweight material

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Authors: Bertalan Jillek, Péter Szabó, Judit Kopniczky, István Szabó, Balázs Patczai, Kinga Turzó

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Hip and knee prostheses are one of the most frequently used medical implants, that can significantly improve patients’ quality of life. Long term success and biointegration of these prostheses depend on several factors, like bulk and surface characteristics, construction and biocompatibility of the material. The applied surgical technique, the general health condition and life-quality of the patient are also determinant factors. Medical devices used in orthopedic surgeries have different surfaces depending on their function inside the human body. Surface roughness of these implants determines the interaction with the surrounding tissues. Numerous modifications have been applied in the recent decades to improve a specific property of an implant. Our goal was to compare the surface characteristics of typical implant materials used in orthopedic surgery and traumatology. Morphological and chemical structure of Vortex plate anodized titanium, cemented THR (total hip replacement) stem high nitrogen REX steel (SS), uncemented THR stem and cup titanium (Ti) alloy with titanium plasma spray coating (TPS), cemented cup and uncemented acetabular liner HXL and UHMWPE and TKR (total knee replacement) femoral component CoCrMo alloy (Sanatmetal Ltd, Hungary) discs were examined. Visualization and elemental analysis were made by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Surface roughness was determined by atomic force microscopy (AFM) and profilometry. SEM and AFM revealed the morphological and roughness features of the examined materials. TPS Ti presented the highest Ra value (25 ± 2 μm, followed by CoCrMo alloy (535 ± 19 nm), Ti (227 ± 15 nm) and stainless steel (170 ± 11 nm). The roughness of the HXL and UHMWPE surfaces was in the same range, 147 ± 13 nm and 144 ± 15 nm, respectively. EDS confirmed typical elements on the investigated prosthesis materials: Vortex plate Ti (Ti, O, P); TPS Ti (Ti, O, Al); SS (Fe, Cr, Ni, C) CoCrMo (Co, Cr, Mo), HXL (C, Al, Ni) and UHMWPE (C, Al). The results indicate that the surface of prosthesis materials have significantly different features and the applied investigation methods are suitable for their characterization. Contact angle measurements and in vitro cell culture testing are further planned to test their surface energy characteristics and biocompatibility.

Keywords: morphology, PE, roughness, titanium

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Authors: Mouna Ettoumi, Jouini Marouen, Carmen Mihaela Neculita, Salah Bouhlel, Lucie Coudert, Mostafa Benzaazoua, Y. Taha

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In the context of sustainable development and circular economy, waste valorization is considered a promising alternative to overcome issues related to their disposal or elimination. The aim of this study is to evaluate the potential use of phosphate sludges (tailings) from the Kef Shfeir mine site (Gafsa, Tunisia) as an alternative material in the production of fired bricks. To do so, representative samples of raw phosphate treatment sludges were collected and characterized for their physical, chemical, mineralogical and environmental characteristics. Then, the raw materials were baked at different temperatures (900°C, 1000°C, and 1100°C) for bricks making. Afterward, fired bricks were characterized for their physical (particle size distribution, density, and plasticity), chemical (XRF and digestion), mineralogical (XRD) and mechanical (flexural strength) properties as well as for their environmental behavior (TCLP, SPLP, and CTEU-9) to ensure whether they meet the required construction standards. Results showed that the raw materials had low density (2.47g/cm 3), were non-plastic and were mainly composed of fluoroapatite (15.6%), calcite (23.1%) and clays (22.2% - mainly as heulandite, vermiculite and palygorskite). With respect to the environmental behavior, all metals (e.g., Pb, Zn, As, Cr, Ba, Cd) complied with the requirements set by the USEPA. In addition, fired bricks had varying porosity (9-13%), firing shrinking (5.2-7.5%), water absorption (12.5-17.2%) and flexural strength (3.86-13.4 MPa). Noteworthy, an improvement in the properties (porosity, firing shrinking, water absorption, and flexural strength) of manufactured fired bricks was observed with the increase of firing temperature from 900 to 1100°C. All the measured properties complied with the construction norms and requirements. Moreover, regardless of the firing temperature, the environmental behavior of metals obeyed the requirements of the USEPA standards. Finally, fired bricks could be produced at high temperatures (1000°C) based on 100% of phosphate sludge without any substitution or addition of either chemical agents or binders. This sustainable brick-making process could be a promising approach for the Phosphate Company to partially manage these wastes, which are considered “non-profitable” for the moment and preserve soils that are exploited presently.

Keywords: phosphate treatment sludge, mine waste, backed bricks, waste valorization

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Authors: Tanapon Keatsamarn, Chuchart Pintavirooj

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Foot pressure measurement provides necessary information for diagnosis diseases, foot insole design, disorder prevention and other application. In this paper, dynamic foot pressure measurement is presented for pressure measuring with high resolution and accuracy. The dynamic foot pressure measurement system consists of hardware and software system. The hardware system uses a transparent acrylic plate and uses steel as the base. The glossy white paper is placed on the top of the transparent acrylic plate and covering with a black acrylic on the system to block external light. Lighting from LED strip entering around the transparent acrylic plate. The optical sensors, the digital cameras, are underneath the acrylic plate facing upwards. They have connected with software system to process and record foot pressure video in avi file. Visual Studio 2017 is used for software system using OpenCV library.

Keywords: foot, foot pressure, image processing, optical sensors

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Authors: Kailash Ghimire, Manoj Thapa

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This study focuses on early identification of deficiencies in pre-required areas of students who are enrolled in College Algebra and Calculus I classes. The students were given pre-diagnostic tests on the first day of the class before they are provided with the syllabus. The tests consist of prerequisite, uniform and advanced content outlined by the University System of Georgia (USG). The results show that 48% of students in College Algebra are lacking prerequisite skills while 52% of Calculus I students are lacking prerequisite skills but, interestingly these students are prior exposed to uniform content and advanced content. The study is still in progress and this paper contains the outcome from Fall 2017 and Spring 2018. In this paper, early intervention used in these classes: two days vs three days meeting a week and students’ self-assessment using exam wrappers and their effectiveness on students’ learning will also be discussed. A result of this study shows that there is an improvement on Drop, Fail and Withdraw (DFW) rates by 7%-10% compared to those in previous semesters.

Keywords: student at risk, diagnostic tests, identification, intervention, normalization gain, validity of tests

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Authors: L. Musak, J. Valachova, T. Vasicko, O. Osina

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Introduction: Stainless steel is resistant to electrochemical corrosion by passivation. Welders are greatly exposed to welding fumes of toxic metals, which added to this steel. The content of chromium (Cr) in steel was above 11.5%, Ni and Mo from 2 to 6.5%. The aim of the study was the evaluation of occupational exposure to Cr, chromosome analysis and valuation of individual susceptibility polymorphism of gene CCND1 c.870 G>A. Materials and Methods: The exposed group was consisted from 117 welders of stainless steels. The average age was 38.43 years and average exposure time 7.14 years. Smokers represented 40.17%. The control group consisted of 123 non-exposed workers with an average age of 39.74 years and time employment 16.67 years. Smokers accounted for 22.76%. Analysis of Cr in blood and urine was performed by atomic absorption spectrophotometry (AAS Varian SpectraAA 30P) with electrothermal decomposition of the sample in the graphite furnace. For the evaluation of chromosomal aberrations (CA) was used cytogenetic analysis of peripheral blood lymphocytes, gene polymorphism was determined by PCR-RFLP reaction using appropriate primers and restriction enzymes. For statistical analysis was used the Mann-Whitney U-test. Results: The mean Cr level in exposed group was 0.095 mmol/l (0.019 min-max 0.504). No value does exceed the average normal value. The average value Cr in urine was 7.9 mmol/mol creatinine (min 0.026 to max 19.26). The total number of CA was 1.86% in compared to 1.70% controls. (CTA-type 0.90% vs 0.80% and CSA-type 0.96% vs 0.90%). In the number of total CA was observed statistical difference between smokers and non-smokers of exposed group (S-1.57% vs. NS-2.04%, P<0.05). In CCND1 gene polymorphisms was observed the increasing of the total CA with wild-type allele (WT) via heterozygous to the VAR genotype (1.44%<1.82%<2.13%). There was observed a statistically higher incidence of CTA-type aberrations in variant genotypes between exposed and control groups (1.22% vs. 0.59%, P<0.05). Discussion and conclusions: The work place is usually higher source of exposure to harmful factors. Workers need consistently and checked frequently health control. In assessing the risk of adverse effects of metals is important to consider their persistence, behavior and bioavailability. Prolonged exposure to carcinogens may not manifest symptoms of poisoning, but delayed effects may occur, which resulted in a higher incidence of malignant tumors.

Keywords: genotoxicity, chromium, stainless steels, welders

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Authors: Adan Valdez, Shawn Gallaher, James Morison, Jordan Aragon

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Global climate change has impacted atmospheric temperatures contributing to rising sea levels, decreasing sea ice, and increased freshening of high latitude oceans. This freshening has contributed to increased stratification inhibiting local mixing and nutrient transport and modifying regional circulations in polar oceans. In recent years, the Western Arctic has seen an increase in freshwater volume at an average rate of 397+-116 km3/year. The majority of the freshwater volume resides in the Beaufort Gyre surface lens driven by anticyclonic wind forcing, sea ice melt, and Arctic river runoff. The total climatological freshwater content is typically defined as water fresher than 34.8. The near-isothermal nature of Arctic seawater and non-linearities in the equation of state for near-freezing waters result in a salinity driven pycnocline as opposed to the temperature driven density structure seen in the lower latitudes. In this study, we investigate the relationship between freshwater content and remotely sensed dynamic ocean topography (DOT). In-situ measurements of freshwater content are useful in providing information on the freshening rate of the Beaufort Gyre; however, their collection is costly and time consuming. NASA’s Advanced Topographic Laser Altimeter System (ATLAS) derived dynamic ocean topography (DOT), and Air Expendable CTD (AXCTD) derived Freshwater Content are used to develop a linear regression model. In-situ data for the regression model is collected across the 150° West meridian, which typically defines the centerline of the Beaufort Gyre. Two freshwater content models are determined by integrating the freshwater volume between the surface and an isopycnal corresponding to reference salinities of 28.7 and 34.8. These salinities correspond to those of the winter pycnocline and total climatological freshwater content, respectively. Using each model, we determine the strength of the linear relationship between freshwater content and satellite derived DOT. The result of this modeling study could provide a future predictive capability of freshwater volume changes in the Beaufort-Chukchi Sea using non in-situ methods. Successful employment of the ICESat-2’s DOT approximation of freshwater content could potentially reduce reliance on field deployment platforms to characterize physical ocean properties.

Keywords: ICESat-2, dynamic ocean topography, freshwater content, beaufort gyre

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Authors: Bo Yang, Hali̇l Ceylan, Ali Ulvi̇ Uzer

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This experimental study was performed to investigate the effect of biofuel co-products (BCPs) with sulfur-free lignin addition on the unconsolidated on strength and durability behavior in pavement soil stabilization subjected to freezing–thawing cycles. For strength behavior, a series of unconfined compression tests were conducted. Mass losses were also calculated after freezing–thawing cycles as criteria for durability behavior. To investigate the effect of the biofuel co-products on the durability behavior of the four type’s soils, mass losses were calculated after 12 freezing–thawing cycles. The co-products tested are promising additives for improving durability under freeze-thaw conditions, and each type has specific advantages.

Keywords: durability, mass lose, freezing–thawing test, bio-energy co-product, soil stabilization

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Authors: G. N. Simonian, R. F. Basalah, F. T. Abd El Halim, F. F. Abd El Latif, A. M. Adel, A. M. El Shafey.

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Carboxymethyl cellulose (CMC) is an anionic water soluble polymer that has been introduced in paper coating as a strength agent. One of the main objectives of this research is to investigate the influence of CMC concentration in improving the strength properties of paper fiber. In this work, we coated the paper sheets; Xerox paper sheets by different concentration of carboxymethyl cellulose solution (0.1, 0.5, 1, 1.5, 2, 3%) w/v. The mechanical properties; breaking length and tearing resistance (tear factor) were measured for the treated and untreated paper specimens. The retained polymer in the coated paper samples were also calculated. The more the concentration of the coating material; CMC increases, the more the mechanical properties; breaking length and tear factor increases. It can be concluded that CMC enhance the improvement of the mechanical properties of paper sheets result in increasing paper stability. The aim of the present research was also to study the effects on the vessel element structure and vessel picking tendency of the coated paper sheets. In addition to the improved strength properties of the treated sheet, a significant decrease in the vessel picking tendency was expected whereas refining of the original paper sheets (untreated paper sheets) improved mainly the bonding ability of fibers, CMC effectively enhanced the bonding of vessels as well. Moreover, film structures were formed in the fibrillated areas of the coated paper specimens, and they were concluded to reinforce the bonding within the sheet. Also, fragmentation of vessel elements through CMC modification was found to be important and results in a decreasing picking tendency which reflects in a good printability. Moreover, Scanning – Electron Microscope (SEM) images are represented to specifically explain the improved bonding ability of vessels and fibers after CMC modification. Finally, CMC modification enhance paper mechanical properties and print quality.

Keywords: carboxymethyl cellulose (CMC), breaking length, tear factor, vessel picking, printing, concentration

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Authors: Rishabh Nagpal, Riya Uchagaonkar, Venkata Naga Narasimha Ashish Mernedi, Ahmed Hambaba

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The rapid evolution of technology in the communication sector continually seeks to bridge the gap between different communities, notably between the deaf community and the hearing world. This project develops a comprehensive American Sign Language (ASL) recognition system, leveraging the advanced capabilities of convolutional neural networks (CNNs) and vision transformers (ViTs) to interpret and translate ASL in real-time. The primary objective of this system is to provide an effective communication tool that enables seamless interaction through accurate sign language interpretation. The architecture of the proposed system integrates dual networks -VGG16 for precise spatial feature extraction and vision transformers for contextual understanding of the sign language gestures. The system processes live input, extracting critical features through these sophisticated neural network models, and combines them to enhance gesture recognition accuracy. This integration facilitates a robust understanding of ASL by capturing detailed nuances and broader gesture dynamics. The system is evaluated through a series of tests that measure its efficiency and accuracy in real-world scenarios. Results indicate a high level of precision in recognizing diverse ASL signs, substantiating the potential of this technology in practical applications. Challenges such as enhancing the system’s ability to operate in varied environmental conditions and further expanding the dataset for training were identified and discussed. Future work will refine the model’s adaptability and incorporate haptic feedback to enhance the interactivity and richness of the user experience. This project demonstrates the feasibility of an advanced ASL recognition system and lays the groundwork for future innovations in assistive communication technologies.

Keywords: sign language, computer vision, vision transformer, VGG16, CNN

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Authors: Kirstin Burger, Paul Watts, Nicole Vorster

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Green chemistry focuses on synthesis which has a low negative impact on the environment. This research focuses on synthesizing novel compounds from an all-natural Eucalyptus citriodora oil. Eight novel plasticizer compounds are synthesized and optimized using flow chemistry technology. A precursor to one novel compound can be synthesized from the lauric acid present in coconut oil. Key parameters, such as catalyst screening and loading, reaction time, temperature, residence time using flow chemistry techniques is investigated. The compounds are characterised using GC-MS, FT-IR, 1H and 13C-NMR techniques, X-ray crystallography. The efficiency of the compounds is compared to two commercial plasticizers, i.e. Dibutyl phthalate and Eastman 168. Several PVC-plasticized film formulations are produced using the bio-based novel compounds. Tensile strength, stress at fracture and percentage elongation are tested. The property of having increasing plasticizer percentage in the film formulations is investigated, ranging from 3, 6, 9 and 12%. The diastereoisomers of each compound are separated and formulated into PVC films, and differences in tensile strength are measured. Leaching tests, flexibility, and change in glass transition temperatures for PVC-plasticized films is recorded. Research objective includes using these novel compounds as a green bio-plasticizer alternative in plastic products for infants. The inhibitory effect of the compounds on six pathogens effecting infants are studied, namely; Escherichia coli, Staphylococcus aureus, Shigella sonnei, Pseudomonas putida, Salmonella choleraesuis and Klebsiella oxytoca.

Keywords: bio-based compounds, plasticizer, tensile strength, microbiological inhibition , synthesis

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Authors: Lan Zhang, Cailing Zhang

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In recent years, many face anti-spoofing algorithms have high detection accuracy when detecting 2D face anti-spoofing or 3D mask face anti-spoofing alone in the field of face anti-spoofing, but their detection performance is greatly reduced in multidimensional and cross-datasets tests. The rPPG method used for face anti-spoofing uses the unique vital information of real face to judge real faces and face anti-spoofing, so rPPG method has strong stability compared with other methods, but its detection rate of 2D face anti-spoofing needs to be improved. Therefore, in this paper, we improve an rPPG(Remote Photoplethysmography) method(MrPPG) for face anti-spoofing which through color space fusion, using the correlation of pulse signals between real face regions and background regions, and introducing the cyclic neural network (LSTM) method to improve accuracy in 2D face anti-spoofing. Meanwhile, the MrPPG also has high accuracy and good stability in face anti-spoofing of multi-dimensional and cross-data datasets. The improved method was validated on Replay-Attack, CASIA-FASD, Siw and HKBU_MARs_V2 datasets, the experimental results show that the performance and stability of the improved algorithm proposed in this paper is superior to many advanced algorithms.

Keywords: face anti-spoofing, face presentation attack detection, remote photoplethysmography, MrPPG

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Authors: Aynur Aker, Hasan Kaya

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Al-12.6wt.%Si-%2wt.Co alloy was prepared in a graphite crucible under vacuum atmosphere. The samples were directionally solidified upwards with different growth rate at constant temperature gradient using by Bridgman–type growth apparatus. The values of microstructures (λ) was measured from transverse sections of the samples. The microhardness (HV), ultimate tensile strength (σ) and electrical resistivity (ρ) of the directional solidification samples were also measured. Influence of the growth rate and spacings on microhardness, ultimate tensile strength and electrical resistivity were investigated and the relationships between them were experimentally obtained by using regression analysis. The results obtained in present work were compared with the previous similar experimental results obtained for binary and ternary alloys.

Keywords: directional solidification, Al-Si-Co alloy, mechanical properties, electrical properties

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Authors: Yujiang Wu

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As electrical machine (e-machine) power density re-querulents become more stringent in vehicle electrification, mounting a temperature sensor for e-machine stator windings becomes increasingly difficult. This can lead to higher manufacturing costs, complicated harnesses, and reduced reliability. In this paper, we propose a deep-learning method for predicting electric machine winding temperature, which can either replace the sensor entirely or serve as a backup to the existing sensor. We compare the performance of our method, the stateful long short-term memory networks (LSTM) with truncated backpropagation through time (TBTT), with that of linear regression, as well as stateless LSTM with/without residual connection. Our results demonstrate the strength of combining stateful LSTM and TBTT in tackling nonlinear time series prediction problems with long sequence lengths. Additionally, in industrial applications, high-temperature region prediction accuracy is more important because winding temperature sensing is typically used for derating machine power when the temperature is high. To evaluate the performance of our algorithm, we developed a temperature-stratified MSE. We propose a simple but effective data preprocessing trick to improve the high-temperature region prediction accuracy. Our experimental results demonstrate the effectiveness of our proposed method in accurately predicting winding temperature, particularly in high-temperature regions, while also reducing manufacturing costs and improving reliability.

Keywords: deep learning, electrical machine, functional safety, long short-term memory networks (LSTM), thermal management, time series prediction

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Authors: S. Alsubari, M. Y. M. Zuhri, S. M. Sapuan, M. R. Ishaks

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Sandwich structures based on cellular cores are increasingly being utilized as energy-absorbing components in the industry. However, determining ideal structural configurations remains challenging. This chapter compares the compression properties of flax fiber-reinforced polylactic acid (PLA) of empty honeycomb core, foam-filled honeycomb and double cell wall square interlocking core sandwich structure under quasi-static compression loading. The square interlocking core is fabricated through a slotting technique, whereas the honeycomb core is made using a corrugated mold that was initially used to create the corrugated core composite profile, which is then cut into corrugated webs and assembled to form the honeycomb core. The sandwich structures are tested at a crosshead displacement rate of 2 mm/min. The experimental results showed that honeycomb outperformed the square interlocking core in terms of their strength capability and SEA by around 14% and 34%, respectively. It is observed that the foam-filled honeycomb collapse in a progressive mode, exhibiting noticeable advantages over the empty honeycomb; this is attributed to the interaction between the honeycomb wall and foam filler. Interestingly, the average SEAs of foam-filled and empty honeycomb cores have no significant difference, around 8.7kJ/kg and 8.2kJ/kg, respectively. In contrast, its strength capability is clearly pronounced, in which the foam-filled core outperforms the empty counterparts by around 33%. Finally, the results for empty and foam-filled cores were significantly superior to aluminum cores published in the literature.

Keywords: compressive strength, flax, honeycomb core, specific energy absorption

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Authors: R. Devicharan

Abstract:

In a short span 3D Printing is expected to play a vital role in our life. The possibility of creativity and speed in manufacturing through various 3D printing processes is infinite. This study is performed on the FDM (Fused Deposition Modelling) method of 3D printing, which is one of the pre-dominant methods of 3D printing technologies. This study focuses on physical properties of the objects produced by 3D printing which determine the applications of the 3D printed objects. This paper specifically aims at the study of the tensile strength and the folding endurance of the 3D printed objects through the FDM (Fused Deposition Modelling) method using the ABS (Acronitirile Butadiene Styrene) and PLA (Poly Lactic Acid) plastic materials. The study is performed on a controlled environment and the specific machine settings. Appropriate tables, graphs are plotted and research analysis techniques will be utilized to analyse, verify and validate the experiment results.

Keywords: FDM process, 3D printing, ABS for 3D printing, PLA for 3D printing, rapid prototyping

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Authors: Xun Sun, Le Li, Ce Mo, Lei Mo, Ruiming Wang, Guosheng Ding

Abstract:

Cognitive control plays a central role in information processing, which is comprised of various components including response suppression and inhibitory control. Response suppression is considered to inhibit the irrelevant response during the cognitive process; while inhibitory control to inhibit the irrelevant stimulus in the process of cognition. Both of them undertake distinct functions for the cognitive control, so as to enhance the performances in behavior. Among numerous factors on cognitive control, bilingual experience is a substantial and indispensible factor. It has been reported that bilingual experience can influence the neural activity of cognitive control as whole. However, it still remains unknown how the neural influences specifically present on the components of cognitive control imposed by bilingualism. In order to explore the further issue, the study applied fMRI, used anti-saccade paradigm and compared the cerebral activations between high and low proficient Chinese-English bilinguals. Meanwhile, the study provided experimental evidence for the brain plasticity of language, and offered necessary bases on the interplay between language and cognitive control. The results showed that response suppression recruited the middle frontal gyrus (MFG) in low proficient Chinese-English bilinguals, but the inferior patrietal lobe in high proficient Chinese-English bilinguals. Inhibitory control engaged the superior temporal gyrus (STG) and middle temporal gyrus (MTG) in low proficient Chinese-English bilinguals, yet the right insula cortex was more active in high proficient Chinese-English bilinguals during the process. These findings illustrate insights that bilingual experience has neural influences on different components of cognitive control. Compared with low proficient bilinguals, high proficient bilinguals turn to activate advanced neural areas for the processing of cognitive control. In addition, with the acquisition and accumulation of language, language experience takes effect on the brain plasticity and changes the neural basis of cognitive control.

Keywords: bilingual experience, cognitive control, inhibition control, response suppression

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Authors: M. L. Burnwal, P. Raychowdhury

Abstract:

Earthquake leads to adverse effects on buildings resting on soft soils. Mitigating the response of shallow foundations on soft soil with different methods reduces settlement and provides foundation stability. Few methods such as the rocking foundation (used in Performance-based design), deep foundation, prefabricated drain, grouting, and Vibro-compaction are used to control the pore pressure and enhance the strength of the loose soils. One of the problems with these methods is that the settlement is uncontrollable, leading to differential settlement of the footings, further leading to the collapse of buildings. The present study investigates the utility of geosynthetics as a potential improvement of the subsoil to reduce the earthquake-induced settlement of structures. A steel moment-resisting frame building resting on loose liquefiable dry soil, subjected to Uttarkashi 1991 and Chamba 1995 earthquakes, is used for the soil-structure interaction (SSI) analysis. The continuum model can simultaneously simulate structure, soil, interfaces, and geogrids in the OpenSees framework. Soil is modeled with PressureDependentMultiYield (PDMY) material models with Quad element that provides stress-strain at gauss points and is calibrated to predict the behavior of Ganga sand. The model analyzed with a tied degree of freedom contact reveals that the system responses align with the shake table experimental results. An attempt is made to study the responses of footing structure and geosynthetics with unreinforced and reinforced bases with varying parameters. The result shows that geogrid reinforces shallow foundation effectively reduces the settlement by 60%.

Keywords: settlement, shallow foundation, SSI, continuum FEM

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Authors: Petcharat  Kerdonfag, Surasak Taneepanichskul, Winai Wadwongtham

Abstract:

Industrial noise is usually considered as the main impact of the environmental health and safety because its exposure can cause permanently serious hearing damage. Despite providing strictly hearing protection standards and campaigning extensively encouraging public health awareness among industrial workers in Thailand, hazard noise-induced hearing loss has dramatically been massive obstacles for workers’ health. The aims of the study were to explore and specify the hearing threshold levels among steel industrial workers responsible in which higher noise levels of work zone and to examine the relationships of hearing loss and workers’ age and the length of employment in Samut Prakan province, Thailand. Cross-sectional study design was done. Ninety-three steel industrial workers in the designated zone of higher noise (> 85dBA) with more than 1 year of employment from two factories by simple random sampling and available to participate in were assessed by the audiometric screening at regional Samut Prakan hospital. Data of doing screening were collected from October to December, 2016 by the occupational medicine physician and a qualified occupational nurse. All participants were examined by the same examiners for the validity. An Audiometric testing was performed at least 14 hours after the last noise exposure from the workplace. Workers’ age and the length of employment were gathered by the developed occupational record form. Results: The range of workers’ age was from 23 to 59 years, (Mean = 41.67, SD = 9.69) and the length of employment was from 1 to 39 years, (Mean = 13.99, SD = 9.88). Fifty three (60.0%) out of all participants have been exposing to the hazard of noise in the workplace for more than 10 years. Twenty-three (24.7%) of them have been exposing to the hazard of noise less than or equal to 5 years. Seventeen (18.3%) of them have been exposing to the hazard of noise for 5 to 10 years. Using the cut point of less than or equal to 25 dBA of hearing thresholds, the average means of hearing thresholds for participants at 4, 6, and 8 kHz were 31.34, 29.62, and 25.64 dB, respectively for the right ear and 40.15, 32.20, and 25.48 dB for the left ear, respectively. The more developing age of workers in the work zone with hazard of noise, the more the hearing thresholds would be increasing at frequencies of 4, 6, and 8 kHz (p =.012, p =.026, p =.024) for the right ear, respectively and for the left ear only at the frequency 4 kHz (p =.009). Conclusion: The participants’ age in the hazard of noise work zone was significantly associated with the hearing loss in different levels while the length of participants’ employment was not significantly associated with the hearing loss. Thus hearing threshold levels among industrial workers would be regularly assessed and needed to be protected at the beginning of working.

Keywords: hearing threshold levels, hazard of noise, hearing loss, audiometric testing

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Authors: G. Minak, D. Ghelli, A. Zucchelli

Abstract:

This paper presents the results of an experimental characterization of a glass fibre-epoxy composite. The behavior of the traditional two-phase composite has been compared with the one of a new three-phase composite where the epoxy matrix was modified by addition of a 3% weight fraction of montmorillonite nano-particles. Two different types of nano-clays, Cloisite® 30B and RXG7000, produced by Southern Clay Products Inc., have been considered. Three-point bending tests, both monotonic and cyclic, were carried out. A strong reduction of the ultimate flexural strength upon nano-modification has been observed in quasi-static tests. Fatigue tests yielded a smaller strength loss. In both quasi-static and fatigue tests a more pronounced tendency to delamination has been noticed in three-phase composites, especially in the case of 30B nano-clay, with respect to the standard two-phase glass fiber composite.

Keywords: bending fatigue, epoxy resin, glass fiber, montmorillonite

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Authors: Emilio A. Berny-Brandt, Sonia E. Ruiz

Abstract:

Steel tubular towers serving as support structures for large wind turbines are subject to several hundred million stress cycles arising from the turbulent nature of the wind. This causes high-cycle fatigue which can govern tower design. The practice of maintaining the support structure after wind turbines reach its typical 20-year design life have become common, but without quantifying the changes in the reliability on the tower. There are several studies on this topic, but most of them are based on the S-N curve approach using the Miner’s rule damage summation method, the de-facto standard in the wind industry. However, the qualitative nature of Miner’s method makes desirable the use of fracture mechanics to measure the effects of fatigue in the capacity curve of the structure, which is important in order to evaluate the integrity and reliability of these towers. Temporal and spatially varying wind speed time histories are simulated based on power spectral density and coherence functions. Simulations are then applied to a SAP2000 finite element model and step-by-step analysis is used to obtain the stress time histories for a range of representative wind speeds expected during service conditions of the wind turbine. Rainflow method is then used to obtain cycle and stress range information of each of these time histories and a statistical analysis is performed to obtain the distribution parameters of each variable. Monte Carlo simulation is used here to evaluate crack growth over time in the tower base using the Paris-Erdogan equation. A nonlinear static pushover analysis to assess the capacity curve of the structure after a number of years is performed. The capacity curves are then used to evaluate the changes in reliability of a steel tower located in Oaxaca, Mexico, where wind energy facilities are expected to grow in the near future. Results show that fatigue on the tower base can have significant effects on the structural capacity of the wind turbine, especially after the 20-year design life when the crack growth curve starts behaving exponentially.

Keywords: crack growth, fatigue, Monte Carlo simulation, structural reliability, wind turbines

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Authors: Lin Huang, Bo Wang, Armando Borgna

Abstract:

Dehydration of glycerol to acrolein was conducted with solid acid catalysts in liquid phase in a batch reactor and in gas phase in a fix-bed reactor, respectively. In the liquid-phase reaction, ZSM-5, H3PO4-modified ZSM-5 and heteropolyacids including H3PW12O40•xH2O (HPW) and Cs2.5H0.5PW12O40 (CsPW) were studied as catalysts. High temperatures and high boiling point solvents such as sulfolane improved the selectivity to acrolein through suppressing the formation of polyglycerols and coke. Catalytic results and temperature-programmed desorption of ammonia showed that the yield of acrolein increased with increasing catalyst acidity within the range of weak acid strength. Weak acid sites favored the selectivity to acrolein whereas strong acid sites promoted the formation of coke. ZSM-5 possessing only acid sites led to a high acrolein yield, while heteropolyacid catalysts with strong acid sites produced a low acrolein yield. In the gas-phase reaction, HPW and CsPW supported on metal oxides such as SiO2, γ-Al2O3, SiO2-Al2O3, ZrO2 and silicate TUD-1 were studied as catalysts. HPW/TUD-1 was most active for the production of acrolein, followed by HPW/SiO2. An acrolein yield of 61 % was obtained over HPW/TUD-1. X-ray diffraction study suggested that HPW and CsPW were stable and more dispersed on SiO2, silicate TUD-1 and SiO2-Al2O3. It was found that the structures of HPW and CsPW were destroyed by interaction with γ-Al2O3 and ZrO2. Compared to CsPW/TUD-1, the higher acrolein yield with HPW/TUD-1 may be attributed to more Brønsted acid sites on HPW/TUD-1, based on preliminary pyridine adsorption IR study.

Keywords: dehydration, glycerol, acrolein, solid acid catalysts, gas-phase, liquid-phase

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Authors: Hazal Yılmaz, Hale Karakaş

Abstract:

In the scope of the study, it is aimed to investigate and review the performance of denim fabrics that are foam washed. Foam washing was compared as an alternative to stone washing in terms of sustainability and performance parameters. For this purpose, seven different denim fabrics, which are both stone washed and foam washed separately in 3 different washing durations (30-60-90 mins), were compared. In the study, the same fabrics were processed with both foam and stone separately. The washing process steps were reviewed, and their water consumption values were compared. After washing, a total of 42 fabric samples were obtained, and tensile strength, tear strength, abrasion, weight loss after abrasion, rubbing fastness, color fastness tests were carried out on the fabric samples. The obtained test results were reviewed and evaluated. As a result of tests, it has been observed that the performance of foam washed fabrics in terms of tensile, tear strength and rubbing fastness test results are better than stone washed fabrics, and it has been seen that foam washed fabrics' color fastness test results are as stone washed. As a result of all these tests, it can be seen that foam washing is an alternative to stone washing due to its performance parameters and its sustainability performance with less water usage.

Keywords: denim fabrics, denim washing, foam washing, performance properties, stone washing, sustainability

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Authors: Taha Ahmed Özbey, Sedat Nazlıbilek, Alparslan Çağrı Yapıcı

Abstract:

Combline cavity filters have gained significant attention in recent years due to their exceptional narrowband characteristics, high unloaded Q, remarkable out-of-band rejection, and versatile post-manufacturing tuning capabilities. These filters play a vital role in various wireless communication systems, radar applications, and other advanced technologies where stringent frequency selectivity and superior performance are required. This paper represents combined cavity filter design and implementation by coupling matrix synthesis. Limited filter length, 50 dB out-of-band rejection, and agile design were aimed. To do so, CAD tools and intuitive methods were used.

Keywords: cavity, band pass filter, cavity combline filter, coupling matrix synthesis

Procedia PDF Downloads 72