Search results for: abrasive wear

Authors: A. Vaidya-Soocheta, K. M. Wong-Hon-Lang

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Craft and fashion have always been interlinked. The combination of both often gives stunning results. The present study introduces ‘Paper Cutting Craft Techniques’ like the Japanese –Kirigami, Mexican –PapelPicado, German –Scherenschnitte, Polish –Wycinankito in textiles to develop innovative and novel design structures as embellishments and ornamentation. The project studies various ways of using these paper cutting techniques to obtain interesting features and delicate design patterns on fabrics. While paper has its advantages and related uses, it is fragile rigid and thus not appropriate for clothing. Fabric is sturdy, flexible, dimensionally stable and washable. In the present study, the cut out techniques develop creative design motifs and patterns to give an inventive and unique appeal to the fabrics. The beauty and fascination of lace in garments have always given them a nostalgic charm. Laces with their intricate and delicate complexity in combination with other materials add a feminine touch to a garment and give it a romantic, mysterious appeal. Various textured and decorative effects through fabric manipulation are experimented along with the use of paper cutting craft skills as an innovative substitute for developing lace or “Broderie Anglaise” effects on textiles. A number of assorted fabric types with varied textures were selected for the study. Techniques to avoid fraying and unraveling of the design cut fabrics were introduced. Fabrics were further manipulated by use of interesting prints with embossed effects on cut outs. Fabric layering in combination with assorted techniques such as cutting of folded fabric, printing, appliqué, embroidery, crochet, braiding, weaving added a novel exclusivity to the fabrics. The fabrics developed by these innovative methods were then tailored into garments. The study thus tested the feasibility and practicability of using these fabrics by designing a collection of evening wear garments based on the theme ‘Nostalgia’. The prototypes developed were complemented by designing fashion accessories with the crafted fabrics. Prototypes of accessories add interesting features to the study. The adaptation and application of this novel technique of paper cutting craft on textiles can be an innovative start for a new trend in textile and fashion industry. The study anticipates that this technique will open new avenues in the world of fashion to incorporate its use commercially.

Keywords: collection, fabric cutouts, nostalgia, prototypes

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Authors: Tejinder Singh Sidhu

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Hot corrosion has been recognized as a severe problem in steam-powered electricity generation plants and industrial waste incinerators as it consumes the material at an unpredictably rapid rate. Consequently, the load-carrying ability of the components reduces quickly, eventually leading to catastrophic failure. The inability to either totally prevent hot corrosion or at least detect it at an early stage has resulted in several accidents, leading to loss of life and/or destruction of infrastructures. A number of countermeasures are currently in use or under investigation to combat hot corrosion, such as using inhibitors, controlling the process parameters, designing a suitable industrial alloy, and depositing protective coatings. However, the protection system to be selected for a particular application must be practical, reliable, and economically viable. Due to the continuously rising cost of the materials as well as increased material requirements, the coating techniques have been given much more importance in recent times. Coatings can add value to products up to 10 times the cost of the coating. Among the different coating techniques, thermal spraying has grown into a well-accepted industrial technology for applying overlay coatings onto the surfaces of engineering components to allow them to function under extreme conditions of wear, erosion-corrosion, high-temperature oxidation, and hot corrosion. In this study, the hot corrosion performances of Ni-20Cr and Cr₃C₂-NiCr coatings developed by High Velocity Oxy-Fuel (HVOF) process have been studied. The coatings were developed on a Fe-based superalloy, and experiments were performed in an actual industrial environment of a coal-fired boiler. The cyclic study was carried out around the platen superheater zone where the temperature was around 1000°C. The study was conducted for 10 cycles, and one cycle was consisting of 100 hours of heating followed by 1 hour of cooling at ambient temperature. Both the coatings deposited on Fe-based superalloy imparted better hot corrosion resistance than the uncoated one. The Ni-20Cr coated superalloy performed better than the Cr₃C₂-NiCr coated in the actual working conditions of the coal fired boiler. It is found that the formation of chromium oxide at the boundaries of Ni-rich splats of the coating blocks the inward permeation of oxygen and other corrosive species to the substrate.

Keywords: hot corrosion, coating, HVOF, oxidation

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Authors: Hernan Arturo Blas López, Gustavo Henndel Lopes, Antonio Carlos Silva Costa Teixeira, Carmen Elena Flores Barreda, Patricia Araujo Pantoja

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Phenols are toxic for life and the environment and may come from many sources. Uncured phenolic monomers present in phenolic resins used as binders in grinding wheels and emery paper can contaminate industrial wastewaters in abrasives manufacture plants. Furthermore, vestiges of resol and novolacs resins generated by wear and tear of abrasives are also possible sources of water contamination by phenolics in these facilities. Fortunately, advanced oxidation by dark Fenton and photo-Fenton techniques are capable of oxidizing phenols and their degradation products up to their mineralization into H₂O and CO₂. The maximal allowable concentrations for phenols in Peruvian waterbodies is very low, such that insufficiently treated effluents from the abrasives industry are a potential environmental noncompliance. The current case study highlights findings obtained during the lab-scale application of Fenton’s and photo-assisted Fenton’s chemistries to real industrial wastewater samples from an abrasives manufacture plant in Peru. The goal was to reduce the phenolic content and sample toxicity. For this purpose, two independent variables-reaction time and effect of ultraviolet radiation–were studied as for their impacts on the concentration of total phenols, total organic carbon (TOC), biological oxygen demand (BOD) and chemical oxygen demand (COD). In this study, diluted samples (1 L) of the industrial effluent were treated with Fenton’s reagent (H₂O₂ and Fe²⁺ from FeSO₄.H₂O) during 10 min in a photochemical batch reactor (Alphatec RFS-500, Brazil) at pH 2.92. In the case of photo-Fenton tests with ultraviolet lamps of 9 W, UV-A, UV-B and UV-C lamps were evaluated. All process conditions achieved 100% of phenols degraded within 5 minutes. TOC, BOD and COD decreased by 49%, 52% and 86% respectively (all processes together). However, Fenton treatment was not capable of reducing BOD, COD and TOC below a certain value even after 10 minutes, contrarily to photo-Fenton. It was also possible to conclude that the processes here studied degrade other compounds in addition to phenols, what is an advantage. In all cases, elevated effluent dilution factors and high amounts of oxidant agent impact negatively the overall economy of the processes here investigated.

Keywords: fenton oxidation, wastewater treatment, phenols, abrasives industry

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Authors: Bulcha Belay Etana, Benny Malengier, Debelo Oljira, Janarthanan Krishnamoorthy, Lieva Vanlangenhove

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Electromyography (EMG) is a technique used to measure the electrical activity of muscles. EMG can be used to assess muscle function in a variety of settings, including clinical, research, and sports medicine. The aim of this study was to develop a wearable textile sensor for EMG monitoring. The sensor was designed to be soft, stretchable, and washable, making it suitable for long-term use. The sensor was fabricated using a conductive thread material that was embroidered onto a fabric substrate. The sensor was then connected to a microcontroller unit (MCU) and a Wi-Fi-enabled module. The MCU was programmed to acquire the EMG signal and transmit it wirelessly to the Wi-Fi-enabled module. The Wi-Fi-enabled module then sent the signal to a server, where it could be accessed by a computer or smartphone. The sensor was able to successfully acquire and transmit EMG signals from a variety of muscles. The signal quality was comparable to that of commercial EMG sensors. The development of this sensor has the potential to improve the way EMG is used in a variety of settings. The sensor is soft, stretchable, and washable, making it suitable for long-term use. This makes it ideal for use in clinical settings, where patients may need to wear the sensor for extended periods of time. The sensor is also small and lightweight, making it ideal for use in sports medicine and research settings. The data for this study was collected from a group of healthy volunteers. The volunteers were asked to perform a series of muscle contractions while the EMG signal was recorded. The data was then analyzed to assess the performance of the sensor. The EMG signals were analyzed using a variety of methods, including time-domain analysis and frequency-domain analysis. The time-domain analysis was used to extract features such as the root mean square (RMS) and average rectified value (ARV). The frequency-domain analysis was used to extract features such as the power spectrum. The question addressed by this study was whether a wearable textile sensor could be developed that is soft, stretchable, and washable and that can successfully acquire and transmit EMG signals. The results of this study demonstrate that a wearable textile sensor can be developed that meets the requirements of being soft, stretchable, washable, and capable of acquiring and transmitting EMG signals. This sensor has the potential to improve the way EMG is used in a variety of settings.

Keywords: EMG, electrode position, smart wearable, textile sensor, IoT, IoT-integrated textile sensor

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Authors: Siyamak Sarafraz, Reza Esmaeil Pour, Saeed Jamshidi, Asghar Molaei Dehkordi

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Cutting transport is one of the major problems in directional and extended reach oil and gas wells. Lack of sufficient attention to this issue may bring some troubles such as casing running, stuck pipe, excessive torque and drag, hole pack off, bit wear, decreased the rate of penetration (ROP), increased equivalent circulation density (ECD) and logging. Since it is practically impossible to directly observe the behavior of deep wells, a test setup was designed to investigate cutting transport phenomena. This experimental work carried out to scrutiny behavior of the effective variables in cutting transport. The test setup contained a test section with 17 feet long that made of a 3.28 feet long transparent glass pipe with 3 inch diameter, a storage tank with 100 liters capacity, drill pipe rotation which made of stainless steel with 1.25 inches diameter, pump to circulate drilling fluid, valve to adjust flow rate, bit and a camera to record all events which then converted to RGB images via the Image Processing Toolbox. After preparation of test process, each test performed separately, and weights of the output particles were measured and compared with each other. Observation charts were plotted to assess the behavior of viscosity, flow rate and RPM in inclinations of 0°, 30°, 60° and 90°. RPM was explored with other variables such as flow rate and viscosity in different angles. Also, effect of different flow rate was investigated in directional conditions. To access the precise results, captured image were analyzed to find out bed thickening and particles behave in the annulus. The results of this experimental study demonstrate that drill string rotation helps particles to be suspension and reduce the particle deposition cutting movement increased significantly. By raising fluid velocity, laminar flow converted to turbulence flow in the annulus. Increases in flow rate in horizontal section by considering a lower range of viscosity is more effective and improved cuttings transport performance.

Keywords: cutting transport, directional drilling, flow rate, hole cleaning, pipe rotation

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Authors: Hansraj Riteesh Bookun, Cassandra Monique Hidajat

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This pilot study investigated the efficacy of a newly designed shoe which will act as an intermittent pneumatic compression device to augment venous flow in the lower limb. The aim was to assess the degree with which a wearable intermittent compression device can increase the venous flow in the popliteal vein. Background: Deep venous thrombosis and chronic venous insufficiency are relatively common problems with significant morbidity and mortality. While mechanical and chemical thromboprophylaxis measures are in place in hospital environments (in the form of TED stockings, intermittent pneumatic compression devices, analgesia, antiplatelet and anticoagulant agents), there are limited options in a community setting. Additionally, many individuals are poorly tolerant of graduated compression stockings due to the difficulty in putting them on, their constant tightness and increased associated discomfort in warm weather. These factors may hinder the management of their chronic venous insufficiency. Method: The device is lightweight, easy to wear and comfortable, with a self-contained power source. It features a Bluetooth transmitter and can be controlled with a smartphone. It is externally almost indistinguishable from a normal shoe. During activation, two bladders are inflated -one overlying the metatarsal heads and the second at the pedal arch. The resulting cyclical increase in pressure squeezes blood into the deep venous system. This will decrease periods of stasis and potentially reduce the risk of deep venous thrombosis. The shoe was fitted to 2 healthy participants and the peak systolic velocity of flow in the popliteal vein was measured during and prior to intermittent compression phases. Assessments of total flow volume were also performed. All haemodynamic assessments were performed with ultrasound by a licensed sonographer. Results: Mean peak systolic velocity of 3.5 cm/s with standard deviation of 1.3 cm/s were obtained. There was a three fold increase in mean peak systolic velocity and five fold increase in total flow volume. Conclusion: The device augments venous flow in the leg significantly. This may contribute to lowered thromboembolic risk during periods of prolonged travel or immobility. This device may also serve as an adjunct in the treatment of chronic venous insufficiency. The study will be replicated on a larger scale in a multi—centre trial.

Keywords: venous, intermittent compression, shoe, wearable device

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Authors: Stephanie Chen, Mitja Echim, Christof Büskens

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To describe and propagate the behavior of a system mathematical models are formulated. Parameter identification is used to adapt the coefficients of the underlying laws of science. For complex systems this approach can be incomplete and hence imprecise and moreover too slow to be computed efficiently. Therefore, these models might be not applicable for the numerical optimization of real systems, since these techniques require numerous evaluations of the models. Moreover not all quantities necessary for the identification might be available and hence the system must be adapted manually. Therefore, an approach is described that generates models that overcome the before mentioned limitations by not focusing on physical laws, but on measured (sensor) data of real systems. The approach is more general since it generates models for every system detached from the scientific background. Additionally, this approach can be used in a more general sense, since it is able to automatically identify correlations in the data. The method can be classified as a multivariate data regression analysis. In contrast to many other data regression methods this variant is also able to identify correlations of products of variables and not only of single variables. This enables a far more precise and better representation of causal correlations. The basis and the explanation of this method come from an analytical background: the series expansion. Another advantage of this technique is the possibility of real-time adaptation of the generated models during operation. Herewith system changes due to aging, wear or perturbations from the environment can be taken into account, which is indispensable for realistic scenarios. Since these data driven models can be evaluated very efficiently and with high precision, they can be used in mathematical optimization algorithms that minimize a cost function, e.g. time, energy consumption, operational costs or a mixture of them, subject to additional constraints. The proposed method has successfully been tested in several complex applications and with strong industrial requirements. The generated models were able to simulate the given systems with an error in precision less than one percent. Moreover the automatic identification of the correlations was able to discover so far unknown relationships. To summarize the above mentioned approach is able to efficiently compute high precise and real-time-adaptive data-based models in different fields of industry. Combined with an effective mathematical optimization algorithm like WORHP (We Optimize Really Huge Problems) several complex systems can now be represented by a high precision model to be optimized within the user wishes. The proposed methods will be illustrated with different examples.

Keywords: adaptive modeling, automatic identification of correlations, data based modeling, optimization

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Authors: Noreen Pulte

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Prior to the 'Back to Sleep' Campaign in 1992, 1 of every 300 infants seen by Advanced Practice Providers had plagiocephaly. Insufficient attention is given to plagiocephaly and brachycephaly diagnoses in practice and pediatric education. In this talk, Nurse Practitioners and Pediatric Providers will be able to: (1) identify red flags associated with head shape abnormalities, (2) learn techniques they can teach parents to prevent head shape abnormalities, and (3) differentiate between plagiocephaly, brachycephaly, and craniosynostosis. The presenter is a Primary Care Pediatric Nurse Practitioner at Ann & Robert H. Lurie Children's Hospital of Chicago and the primary provider for its head shape abnormality clinics. She will help participants translate key information obtained from birth history, review of systems, and developmental history to understand risk factors for head shape abnormalities and progression of deformities. Synostotic and non-synostotic head shapes will be explained to help participants differentiate plagiocephaly and brachycephaly from synostotic head shapes. This knowledge is critical for the prompt referral of infants with craniosynostosis for surgical evaluation and correction. Rapid referral for craniosynostosis can possibly direct the patient to a minimally invasive surgical procedure versus a craniectomy. As for plagiocephaly and brachycephaly, this timely referral can also aid in a physical therapy referral if necessitated, which treats torticollis and aids in improving head shape. A well-timed referral to a head shape clinic can possibly eliminate the need for a helmet and/or minimize the time in a helmet. Practitioners will learn the importance of obtaining head measurements using calipers. The presenter will explain head calculations and how the calculations are interpreted to determine the severity of the head shape abnormalities. Severity defines the treatment plan. Participants will learn when to refer patients to a head shape abnormality clinic and techniques they should teach parents to perform while waiting for the referral appointment. The purpose, mechanics, and logistics of helmet therapy, including optimal time to initiate helmet therapy, recommended helmet wear-time, and tips for helmet therapy compliance, will be described. Case scenarios will be incorporated into the presenter's presentation to support learning. The salient points of the case studies will be explained and discussed. Practitioners will be able to immediately translate the knowledge and skills gained in this presentation into their clinical practice.

Keywords: plagiocephaly, brachycephaly, craniosynostosis, red flags

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Authors: Ankush Raina, Ankush Anand

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Plyometric training is a form of specialised strength training that uses fast muscular contractions to improve power and speed in sports conditioning by coaches and athletes. Despite its useful role in sports conditioning programme, the information about plyometric training on the athletes cardiovascular health especially Electrocardiogram (ECG) has not been established in the literature. The purpose of the study was to determine the effects of lower and upper body plyometric training on ECG of athletes. The study was guided by three null hypotheses. Quasi–experimental research design was adopted for the study. Seventy-two university male athletes constituted the population of the study. Thirty male athletes aged 18 to 24 years volunteered to participate in the study, but only twenty-three completed the study. The volunteered athletes were apparently healthy, physically active and free of any lower and upper extremity bone injuries for past one year and they had no medical or orthopedic injuries that may affect their participation in the study. Ten subjects were purposively assigned to one of the three groups: lower body plyometric training (LBPT), upper body plyometric training (UBPT), and control (C). Training consisted of six plyometric exercises: lower (ankle hops, squat jumps, tuck jumps) and upper body plyometric training (push-ups, medicine ball-chest throws and side throws) with moderate intensity. The general data were collated and analysed using Statistical Package for Social Science (SPSS version 22.0). The research questions were answered using mean and standard deviation, while paired samples t-test was also used to test for the hypotheses. The results revealed that athletes who were trained using LBPT had reduced ECG parameters better than those in the control group. The results also revealed that athletes who were trained using both LBPT and UBPT indicated lack of significant differences following ten weeks plyometric training than those in the control group in the ECG parameters except in Q wave, R wave and S wave (QRS) complex. Based on the findings of the study, it was recommended among others that coaches should include both LBPT and UBPT as part of athletes’ overall training programme from primary to tertiary institution to optimise performance as well as reduce the risk of cardiovascular diseases and promotes good healthy lifestyle.

Keywords: boundary lubrication, copper oxide, friction, nano diamond

Procedia PDF Downloads 124

Authors: Tolulope Aremu

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This paper is based on the idea of using deep learning methodology for optimizing production yield by tuning a few key process parameters in a manufacturing environment. The study was explicitly on how to maximize production yield and minimize operational costs by utilizing advanced neural network models, specifically Long Short-Term Memory and Convolutional Neural Networks. These models were implemented using Python-based frameworks—TensorFlow and Keras. The targets of the research are the precision molding processes in which temperature ranges between 150°C and 220°C, the pressure ranges between 5 and 15 bar, and the material flow rate ranges between 10 and 50 kg/h, which are critical parameters that have a great effect on yield. A dataset of 1 million production cycles has been considered for five continuous years, where detailed logs are present showing the exact setting of parameters and yield output. The LSTM model would model time-dependent trends in production data, while CNN analyzed the spatial correlations between parameters. Models are designed in a supervised learning manner. For the model's loss, an MSE loss function is used, optimized through the Adam optimizer. After running a total of 100 training epochs, 95% accuracy was achieved by the models recommending optimal parameter configurations. Results indicated that with the use of RSM and DOE traditional methods, there was an increase in production yield of 12%. Besides, the error margin was reduced by 8%, hence consistent quality products from the deep learning models. The monetary value was annually around $2.5 million, the cost saved from material waste, energy consumption, and equipment wear resulting from the implementation of optimized process parameters. This system was deployed in an industrial production environment with the help of a hybrid cloud system: Microsoft Azure, for data storage, and the training and deployment of their models were performed on Google Cloud AI. The functionality of real-time monitoring of the process and automatic tuning of parameters depends on cloud infrastructure. To put it into perspective, deep learning models, especially those employing LSTM and CNN, optimize the production yield by fine-tuning process parameters. Future research will consider reinforcement learning with a view to achieving further enhancement of system autonomy and scalability across various manufacturing sectors.

Keywords: production yield optimization, deep learning, tuning of process parameters, LSTM, CNN, precision manufacturing, TensorFlow, Keras, cloud infrastructure, cost saving

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Authors: Robert John Godby

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To be responsive now and in the future, workplaces must address the demands of multicultural teams as they become more common elements of the global labor force. This is especially the case for aged care due to the aging population, industry growth and migrant recruitment. This research identifies influences on and improvements for learning in these environments. Its unique contribution is to illuminate how culturally diverse workplaces can work and learn together more effectively. A mixed-methods approach was used to gather data about this topic in two phases. Firstly, the research methods included a survey of 102 aged care workers around Australia from two multi-site aged care organisations. The questionnaire elicited both quantitative and qualitative data about worker characteristics and perspectives on working and learning in aged care. Secondly, a case study of one aged care worksite was formulated drawing on worksite information and interviews with workers. A review of the literature suggests that learning in multicultural work environments is influenced by three main factors: 1) the individual workers themselves, 2) their interaction with each other and 3) the environment in which they work. There are various accounts of these three factors, how they are manifested and how they lead to a change in workers’ disposition, knowledge, or expertise when confronted with new circumstances. The study has found that a key individual factor influencing learning is cultural background. Their unique view of the world was shown to affect their approach to both their work and co-working. Interactional factors suggest that the high requirement for collaboration in aged care positively supports learning in this context; however, it can be hindered by cultural bias and spoken accent. The study also found that environmental factors, such as disruptions caused by the pandemic, were another key influence. For example, the need to wear face masks hindered the communication needed for workplace learning. This was especially challenging due to the diverse language backgrounds and abilities within the teams. Potential improvements for learning in multicultural aged care work environments were identified. These include more frequent and structured inter-peer learning (e.g. buddying), communication training (e.g. English language usage for both native and non-native speaking workers) and support for cross-cultural habitude (e.g. recognizing and adapting to cultural differences). Workplace learning in cross-cultural aged care environments is an area that is not extensively dealt with in the literature. This study addresses this gap and holds the potential to contribute practical insights to aged care and other diverse industries.

Keywords: cross-cultural learning, learning in aged care, migrant learning, workplace learning

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Authors: Nurten Akgun, Dilum Dissanayake, Neil Thorpe, Margaret C. Bell

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Cycling has gained a great attention with comparable speeds, low cost, health benefits and reducing the impact on the environment. The main challenge associated with cycling is the provision of safety for the people choosing to cycle as their main means of transport. From the road safety point of view, cyclists are considered as vulnerable road users because they are at higher risk of serious casualty in the urban network but more specifically at roundabouts. This research addresses the development of an enhanced mathematical model by including a broad spectrum of casualty related variables. These variables were geometric design measures (approach number of lanes and entry path radius), speed limit, meteorological condition variables (light, weather, road surface) and socio-demographic characteristics (age and gender), as well as contributory factors. Contributory factors included driver’s behavior related variables such as failed to look properly, sudden braking, a vehicle passing too close to a cyclist, junction overshot, failed to judge other person’s path, restart moving off at the junction, poor turn or manoeuvre and disobeyed give-way. Tyne and Wear in the UK were selected as a case study area. The cyclist casualty data was obtained from UK STATS19 National dataset. The reference categories for the regression model were set to slight and serious cyclist casualties. Therefore, binary logistic regression was applied. Binary logistic regression analysis showed that approach number of lanes was statistically significant at the 95% level of confidence. A higher number of approach lanes increased the probability of severity of cyclist casualty occurrence. In addition, sudden braking statistically significantly increased the cyclist casualty severity at the 95% level of confidence. The result concluded that cyclist casualty severity was highly related to approach a number of lanes and sudden braking. Further research should be carried out an in-depth analysis to explore connectivity of sudden braking and approach number of lanes in order to investigate the driver’s behavior at approach locations. The output of this research will inform investment in measure to improve the safety of cyclists at roundabouts.

Keywords: binary logistic regression, casualty severity, cyclist safety, roundabout

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Authors: Ahmed Tamer AlMotasem, Jens Bergström, Anders Gåård, Pavel Krakhmalev, Thijs Jan Holleboom

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In sheet metal forming processes, accumulation and transfer of sheet material to tool surfaces, often referred to as galling, is the major cause of tool failure. Initiation of galling is assumed to occur due to local adhesive wear between two surfaces. Therefore, reducing adhesion between the tool and the work sheet has a great potential to improve the tool materials galling resistance. Experimental observations and theoretical studies show that the presence of primary micro-sized carbides and/or nitrides in alloyed steels may significantly improve galling resistance. Generally, decreased adhesion between the ceramic precipitates and the sheet material counter-surface are attributed as main reason to the latter observations. On the other hand, adhesion processes occur at an atomic scale and, hence, fundamental understanding of galling can be obtained via atomic scale simulations. In the present study, molecular dynamics simulations are used, with utilizing second nearest neighbor embedded atom method potential to investigate the influence of nano-sized cementite precipitates embedded in tool atoms. The main aim of the simulations is to gain new fundamental knowledge on galling initiation mechanisms. Two tool/work piece configurations, iron/iron and iron-cementite/iron, are studied under dry sliding conditions. We find that the average frictional force decreases whereas the normal force increases for the iron-cementite/iron system, in comparison to the iron/iron configuration. Moreover, the average friction coefficient between the tool/work-piece decreases by about 10 % for the iron-cementite/iron case. The increase of the normal force in the case of iron-cementite/iron system may be attributed to the high stiffness of cementite compared to bcc iron. In order to qualitatively explain the effect of cementite on adhesion, the adhesion force between self-mated iron/iron and cementite/iron surfaces has been determined and we found that iron/cementite surface exhibits lower adhesive force than that of iron-iron surface. The variation of adhesion force with temperature was investigated up to 600 K and we found that the adhesive force, generally, decreases with increasing temperature. Structural analyses show that plastic deformation is the main deformation mechanism of the work-piece, accompanied with dislocations generation.

Keywords: adhesion, cementite, galling, molecular dynamics

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Authors: M. H. Arslan, U. K. Sahin, H. Acikgoz-Tufan, I. Gocek, I. Erdem

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Various exterior factors have perpetual effects on textile materials during wear, use and laundering in everyday life. In accordance with their frequency of use, textile materials are required to be laundered at certain intervals. The medium in which the laundering process takes place have inevitable detrimental physical and chemical effects on textile materials caused by the unique parameters of the process inherently existing. Connatural structures of various textile materials result in many different physical, chemical and mechanical characteristics. Because of their specific structures, these materials have different behaviors against several exterior factors. By modeling the behavior of commercial and test textiles as group-wise against laundering process, it is possible to disclose the relation in between these two groups of materials, which will lead to better understanding of their behaviors in terms of similarities and differences against the washing parameters of the laundering. Thus, the goal of the current research is to examine the behavior of two groups of textile materials as commercial textiles and as test textiles towards the main washing machine parameters during laundering process such as temperature, load quantity, mechanical action and level of water amount by concentrating on shrinkage, pilling, sewing defects, collar abrasion, the other defects other than sewing, whitening and overall properties of textiles. In this study, cotton fabrics were preferred as commercial textiles due to the fact that garments made of cotton are the most demanded products in the market by the textile consumers in daily life. Full factorial experimental set-up was used to design the experimental procedure. All profiles always including all of the commercial and the test textiles were laundered for 20 cycles by commercial home laundering machine to investigate the effects of the chosen parameters. For the laundering process, a modified version of ‘‘IEC 60456 Test Method’’ was utilized. The amount of detergent was altered as 0.5% gram per liter depending on varying load quantity levels. Datacolor 650®, EMPA Photographic Standards for Pilling Test and visual examination were utilized to test and characterize the textiles. Furthermore, in the current study the relation in between commercial and test textiles in terms of their performance was deeply investigated by the help of statistical analysis performed by MINITAB® package program modeling their behavior against the parameters of the laundering process. In the experimental work, the behaviors of both groups of textiles towards washing machine parameters were visually and quantitatively assessed in dry state.

Keywords: behavior against washing machine parameters, performance evaluation of textiles, statistical analysis, commercial and test textiles

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Authors: Michal Brazda, Miroslav Urbanek, Martina Koukolikova

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This work focuses on the development of functional surfaces and edges for cutting and forming tools created through the Directed Energy Deposition (DED) technology. In the context of growing challenges in modern engineering, additive technologies, especially DED, present an innovative approach to manufacturing tools for forming and cutting. One of the key features of DED is its ability to precisely and efficiently deposit Fully dense metals from powder feedstock, enabling the creation of complex geometries and optimized designs. Gradually, it becomes an increasingly attractive choice for tool production due to its ability to achieve high precision while simultaneously minimizing waste and material costs. Tools created using DED technology gain significant durability through the utilization of high-performance materials such as nickel alloys and tool steels. For high-temperature applications, Nimonic 80A alloy is applied, while for cold applications, M2 tool steel is used. The addition of ceramic materials, such as tungsten carbide, can significantly increase the tool's resistance. The introduction of functionally graded materials is a significant contribution, opening up new possibilities for gradual changes in the mechanical properties of the tool and optimizing its performance in different sections according to specific requirements. In this work, you will find an overview of individual applications and their utilization in the industry. Microstructural analyses have been conducted, providing detailed insights into the structure of individual components alongside examinations of the mechanical properties and tool life. These analyses offer a deeper understanding of the efficiency and reliability of the created tools, which is a key element for successful development in the field of cutting and forming tools. The production of functional surfaces and edges using DED technology can result in financial savings, as the entire tool doesn't have to be manufactured from expensive special alloys. The tool can be made from common steel, onto which a functional surface from special materials can be applied. Additionally, it allows for tool repairs after wear and tear, eliminating the need for producing a new part and contributing to an overall cost while reducing the environmental footprint. Overall, the combination of DED technology, functionally graded materials, and verified technologies collectively set a new standard for innovative and efficient development of cutting and forming tools in the modern industrial environment.

Keywords: additive manufacturing, directed energy deposition, DED, laser, cutting tools, forming tools, steel, nickel alloy

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Authors: D. Hilton

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The importance and significance of this research is based upon the fundamental knowledge reported in the scientific literature that physical activity is inversely associated with obesity. In addition, it is recognized there is a global epidemic of sedentariness while at the same time it is known that morbidity and mortality are associated with physical inactivity and as a result of overweight or obesity. Hence this small study in school students is an important area of research in our community. An application submitted in 2005 for the inaugural Public Health Education Research Trust [PHERT] Post Graduate Research Scholarship scheme organized by the Public Health Association of Australia [PHAA] was awarded 3rd place within Australia. The author and title was: D. Hilton, Methods to increase physical activity in school aged children [literature review, a trial using pedometers and a policy paper]. Third place is a good result, however this did not secure funding for the project, as only first place received $5000 funding. Some years later within Australia, a program commenced called the Global Children's Challenge [GCC]. Given details of the 2005 award above were included an application submission prepared for Parkhill Primary School [PPS] which is located in Victoria, Australia was successful. As a result, an excited combined grade 3/ 4 class at the school [27 students] in 2012 became recipients of these free pedometers. Ambassadors for the program were Mrs Catherine Freeman [OAM], Olympic Gold Medalist – Sydney 2000 [400 meters], while another ambassador was Mr Colin Jackson [CBE] who is a Welsh former sprint and hurdling athlete. In terms of PPS and other schools involved in 2012, website details show that the event started on 19th Sep 2012 and students were to wear the pedometer every day for 50 days [at home and at school] aiming for the recommended 15,000 steps/day recording steps taken in a booklet provided. After the finish, an analysis of the average step count for this school showed that the average steps taken / day was 14, 003 [however only a small percentage of students returned the booklets and units] as unfortunately the dates for the program coincided with school holidays so some students either forgot or misplaced the units / booklets. Unfortunately funding for this program ceased in 2013, however the lasting impact of the trial on student’s knowledge and awareness remains and in fact becomes a good grounding for students in how to monitor basic daily physical activity using a method that is easy, fun, low cost and readily accessible.

Keywords: walking, physical activity, exercise, Australian school

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Authors: Anushka Saxena, Rakhi Wahee Pratap

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Skincare textiles, an emerging field at the crossroads of textile technology and wellness, offer groundbreaking innovations that aim to enhance health and well-being through everyday wear. This research paper explores the diverse spectrum of skin-friendly textiles, with a focus on key categories such as cosmetotextiles, skincare finishes, marine collagen fabrics, and nanotextiles. These developments reflect a shift towards a more holistic approach to clothing, where garments not only serve as fashion or protection but also contribute actively to personal care and wellness. Cosmetotextiles represent a transformative fusion of beauty and textile industries, where fabrics are impregnated with active cosmetic ingredients that provide skincare benefits as they are worn. By incorporating substances such as vitamins, moisturizers, essential oils, and antioxidants, these textiles continuously release beneficial ingredients to the skin throughout the day. The result is improved skin hydration, enhanced smoothness, and targeted therapeutic effects that redefine how clothing can interact with the body. Marine collagen fabrics introduce a novel approach to skincare, harnessing collagen derived from marine life to improve skin elasticity, hydration, and overall texture. With their natural bioactive compounds, these textiles can help stimulate skin repair and rejuvenation, positioning them as a promising tool in both beauty and medical applications. Marine collagen offers the dual benefit of contributing to sustainable textiles while delivering scientifically-backed skincare benefits. Nanotextiles, on the other hand, leverage the advancements in nanotechnology by integrating nanoparticles into fabric structures. These textiles exhibit multifunctional properties, such as antimicrobial action, UV protection, and wound-healing capabilities, making them highly suitable for medical textiles. Nanotextiles provide an avenue for creating clothing that not only protects the skin from environmental aggressors but also aids in recovery, regeneration, and long-term health maintenance. This paper provides an in-depth overview of healing textiles, examining their current advancements, practical applications, and the challenges faced in their development. Furthermore, it explores the future prospects of this innovative field, particularly its potential in bridging the gap between cutting-edge technology and traditional textile practices. As consumer demand for multifunctional and health-promoting textiles grows, healing textiles present a promising solution for improving quality of life through fabric innovation.

Keywords: skincare textiles, nanotechnology, cosmetotextiles, nanotextiles, marine collagen textiles and health

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Authors: Vishnu Emani, Andreas Escher, Ellen Roche

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Background: Orthostatic hypotension (OH) is an autonomic disorder marked by a sudden drop in blood pressure upon standing resulting from autonomic dysfunction. OH is especially prevalent in elderly populations, affecting more than 30% of Americans over the age of 70. OH is one of the most significant risk factors for accidental falls in elderly populations, making it a crucial focus for medical and device therapies. Pharmacologic therapy with midodrine and fludrocortisone may alleviate hypotension but have significant adverse side effects. Abdominal passive compression devices (binders) are more effective than lower extremity compression stockings at mitigating postural hypotension, by improving venous return to the heart. However, abdominal binders are difficult to don and uncomfortable to wear, leading to poor compliance. A disadvantage of passive compression devices is their inability to selectively compress during the crucial moment of standing. We have recently developed an active compression device that applies external pressure on the abdomen during the transition from a prone to a supine position and conducted initial prototype testing. Methods: An active abdominal compression device was developed utilizing a simple, servo-driven straptightening mechanism to supply tension onto foam fabric, which applies pressure to the abdomen. Healthy volunteers (n=5) were utilized for prototype testing and were subjected to three conditions: no compression, passive compression (i.e. standard abdominal binder), and active compression (device prototype). Abdominal applied pressure during device activation was measured by a strain-gauge manometer placed between the skin and binder. Systolic (SBP) and mean (MAP) arterial blood pressure was measured by standard blood pressure cuff in supine position followed by repeat measurements at 1 minute intervals for 5 minutes following upright position. A survey tool was administered to determine scores (1-10) for comfort and ease of donning abdominal binders. Results: Abdominal pressure increased from 0 to 15±3 mmHg upon device activation for both passive and active compression devices. During the transition from supine to an upright position, both active and passive compression devices demonstrated significantly higher MAP compared to the no-compression condition (67±4, 68±5, 62±5 respectively, P<0.05), but there was no statistically significant difference in SBP or MAP when comparing active to passive compression. Active compression demonstrated significantly higher comfort scores (8.3±1) compared to passive compression (3.2±2) but lower when compared to no compression (10). Subjects universally reported that active compression device was easier to don compared to passive device. Conclusions: Active or passive abdominal compression prevents hypotension associated with postural changes. Active compression is associated with increased comfort and ease of donning compared to passive compression devices. Future trials are warranted to investigate the efficacy of our device in patients with OH.

Keywords: orthostatic hypotension, compression binder, abdominal binder, active abdominal compression

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Authors: Vicki R. Voskuil, Jorgie M. Watson

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Despite the well-established health benefits of physical activity (PA), most adolescents do not meet guidelines recommending 60 minutes of moderate to vigorous physical activity (MVPA) each day. Adolescent girls engage in less PA than boys, a difference that increases with age. By the 9th grade, only 20% of girls report meeting recommendations for PA with lower percentages for black and Hispanic girls compared to white girls. The purpose of the study was to explore the physical activity (PA) behavior and needs of adolescent girls. Study aims included assessment of adolescent girls’ PA behavior; facilitators of and barriers to PA, PA needs, and acceptability of the Fitbit-Flex 2 activity tracker. This exploratory study used a qualitative and quantitative approach. The qualitative approach involved a focus group using a semi-structured interview technique. PA was measured using the Fitbit-Flex 2 activity tracker. Steps, distance, and active minutes were recorded for one week. A Fitbit survey was also administered to assess acceptability. SPSS Version 22.0 and ATLAS.ti Version 8 were used to analyze data. Girls in the ninth grade were recruited from a high school in the Midwest (n=11). Girls were excluded if they were involved in sports or other organized PA ≥ 3 days per week, had a health condition that prevented or limited PA, or could not read and write English. Participants received a Fitbit-Flex 2 activity tracker to wear for one week. At the end of the week, girls returned the Fitbit and participated in a focus group. Girls responded to open-ended questions regarding their PA behavior and shared their ideas for future intervention efforts aimed at increasing PA among adolescents. Girls completed a survey assessing their perceptions of the Fitbit. Mean age of the girls was 15.3 years (SD=0.44). On average girls took 6,520 steps and walked 2.73 miles each day. Girls stated their favorite types of PA were walking, riding bike, and running. Most girls stated they did PA for 30 minutes or more at a time once a day or every other day. The top 3 facilitators of PA reported by girls were friends, family, and transportation. The top 3 barriers included health issues, lack of motivation, and weather. Top intervention ideas were community service projects, camps, and using a Fitbit activity tracker. Girls felt the best timing of a PA program would be in the summer. Fitbit survey results showed 100% of girls would use a Fitbit on most days if they had one. Ten (91%) girls wore the Fitbit on all days. Seven (64%) girls used the Fitbit app and all reported they liked it. Findings indicate that PA participation for this sample is consistent with previous studies. Adolescent girls are not meeting recommended daily guidelines for PA. Fitbit activity trackers were positively received by all participants and could be used in future interventions aimed at increasing PA for adolescent girls. PA interventions that take place in the summer with friends and include community service projects may increase PA and be well received by this population.

Keywords: adolescents, girls, interventions, physical activity

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Authors: Tatiana S. Ogneva

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Aluminum and nickel-based intermetallic compounds have attracted the attention of scientific community as promising materials for heat-resistant and wear-resistant coatings in such manufacturing areas as microelectronics, aircraft and rocket building and chemical industries. Magnetron sputtering makes possible to coat materials without formation of liquid phase and improves the mechanical and functional properties of nickel aluminides due to the possibility of nanoscale structure formation. The purpose of the study is the investigation of structure and properties of intermetallic coatings produced by magnetron sputtering technique. The feature of this work is the using of composite targets for sputtering, which were consisted of two semicircular sectors of cp-Ni and cp-Al. Plates of alumina, silicon, titanium and steel alloys were used as substrates. To estimate sputtering conditions on structure of intermetallic coatings, a series of samples were produced and studied in detail using scanning and transition electron microcopy and X-Ray diffraction. Besides, nanohardness and scratching tests were carried out. The varying parameters were the distance from the substrate to the target, the duration and the power of the sputtering. The thickness of the obtained intermetallic coatings varied from 0.05 to 0.5 mm depending on the sputtering conditions. The X-ray diffraction data indicated that the formation of intermetallic compounds occurred after sputtering without additional heat treatment. Sputtering at a distance not closer than 120 mm led to the formation of NiAl phase. Increase in the power of magnetron from 300 to 900 W promoted the increase of heterogeneity of the phase composition and the appearance of intermetallic phases NiAl, Ni₂Al₃, NiAl₃, and Al under the aluminum side, and NiAl, Ni₃Al, and Ni under the nickel side of the target. A similar trend is observed with increasing the distance of sputtering from 100 to 60 mm. The change in the phase composition correlates with the changing of the atomic composition of the coatings. Scanning electron microscopy revealed that the coatings have a nanoscale grain structure. In this case, the substrate material and the distance from the substrate to the magnetron have a significant effect on the structure formation process. The size of nanograins differs from 10 to 83 nm and depends not only on the sputtering modes but also on material of a substrate. Nanostructure of the material influences the level of mechanical properties. The highest level of nanohardness of the coatings deposited during 30 minutes on metallic substrates at a distance of 100 mm reached 12 GPa. It was shown that nanohardness depends on the grain size of the intermetallic compound. Scratching tests of the coatings showed a high level of adhesion of the coating to substrate without any delamination and cracking. The results of the study showed that magnetron sputtering of composite targets consisting of nickel and aluminum semicircles makes it possible to form intermetallic coatings with good mechanical properties directly in the process of sputtering without additional heat treatment.

Keywords: intermetallic coatings, magnetron sputtering, mechanical properties, structure

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Authors: Sandra Christina Gressler

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Resting is essentially the physical and mental relaxation. So, can behaviors that go beyond the merely physical relaxation to some extent be understood as a behavior of restoration? Studies on restorative environments emphasize the physical, mental and social benefits that some environments can provide and suggest that activities in natural environments reduce the stress of daily lives, promoting recovery against the daily wear. These studies, though specific in their results, do not unify the different possibilities of restoration. Considering the importance of restorative environments by promoting well-being, this research aims to verify the applicability of the theory on restorative environments in a Brazilian context, inquiring about the environment/behavior of rest. The research sought to achieve its goals by; a) identifying daily ways of how participants interact/connect with nature; b) identifying the resting environments/behavior; c) verifying if rest strategies match the restorative environments suggested by restorative studies; and d) verifying different rest strategies related to time. Workers from different companies in which certain functions require focused attention, and high school students from different schools, participated in this study. An interview was used to collect data and information. The data obtained were compared with studies of attention restoration theory and stress recovery. The collected data were analyzed through the basic descriptive inductive statistics and the use of the software ALCESTE® (Analyse Lexicale par Contexte d'un Ensemble de Segments de Texte). The open questions investigate perception of nature on a daily basis – analysis using ALCESTE; rest periods – daily, weekends and holidays – analysis using ALCESTE with tri-croisé; and resting environments and activities – analysis using a simple descriptive statistics. According to the results, environments with natural characteristics that are compatible with personal desires (physical aspects and distance) and residential environments when they fulfill the characteristics of refuge, safety, and self-expression, characteristics of primary territory, meet the requirements of restoration. Analyzes suggest that the perception of nature has a wide range that goes beyond the objects nearby and possible to be touched, as well as observation and contemplation of details. The restoration processes described in the studies of attention restoration theory occur gradually (hierarchically), starting with being away, following compatibility, fascination, and extent. They are also associated with the time that is available for rest. The relation between rest behaviors and the bio-demographic characteristics of the participants are noted. It reinforces, in studies of restoration, the need to insert not only investigations regarding the physical characteristics of the environment but also behavior, social relationship, subjective reactions, distance and time available. The complexity of the theme indicates the necessity for multimethod studies. Practical contributions provide subsidies for developing strategies to promote the welfare of the population.

Keywords: attention restoration theory, environmental psychology, rest behavior, restorative environments

Procedia PDF Downloads 197

Authors: Pedro Gomes, Luís Sá Castelo, António Lopes, Marta Maio, Pedro Mota, Adélia Avelar, António Marques Dias

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Introduction: Total Knee Arthroplasty (TKA) has contributed to improvement of patient`s quality of life, although it has been associated with some complications including component loosening and polyethylene wear. To prevent these complications various fixation techniques have been employed. Hybrid TKA with cemented tibial and cementless femoral components have shown favourable outcomes, although it still lack of consensus in the literature. Objectives: To evaluate the clinical and radiographic results of hybrid versus cemented TKA with an average 5 years follow-up and analyse the survival rates. Methods: A retrospective study of 125 TKAs performed in 92 patients at our institution, between 2006 to 2008, with a minimum follow-up of 2 years. The same prosthesis was used in all knees. Hybrid TKA fixation was performed in 96 knees, with a mean follow-up of 4,8±1,7 years (range, 2–8,3 years) and 29 TKAs received fully cemented fixation with a mean follow-up of 4,9±1,9 years (range, 2-8,3 years). Selection for hybrid fixation was nonrandomized and based on femoral component fit. The Oxford Knee Score (OKS 0-48) was evaluated for clinical assessment and Knee Society Roentgenographic Evaluation Scoring System was used for radiographic outcome. The survival rate was calculated using the Kaplan-Meier method, with failures defined as revision of either the tibial or femoral component for aseptic failures and all-causes (aseptic and infection). Analysis of survivorship data was performed using the log-rank test. SPSS (v22) was the computer program used for statistical analysis. Results: The hybrid group consisted of 72 females (75%) and 24 males (25%), with mean age 64±7 years (range, 50-78 years). The preoperative diagnosis was osteoarthritis (OA) in 94 knees (98%), rheumatoid arthritis (RA) in 1 knee (1%) and Posttraumatic arthritis (PTA) in 1 Knee (1%). The fully cemented group consisted of 23 females (79%) and 6 males (21%), with mean age 65±7 years (range, 47-78 years). The preoperative diagnosis was OA in 27 knees (93%), PTA in 2 knees (7%). The Oxford Knee Scores were similar between the 2 groups (hybrid 40,3±2,8 versus cemented 40,2±3). The percentage of radiolucencies seen on the femoral side was slightly higher in the cemented group 20,7% than the hybrid group 11,5% p0.223. In the cemented group there were significantly more Zone 4 radiolucencies compared to the hybrid group (13,8% versus 2,1% p0,026). Revisions for all causes were performed in 4 of the 96 hybrid TKAs (4,2%) and 1 of the 29 cemented TKAs (3,5%). The reason for revision was aseptic loosening in 3 hybrid TKAs and 1 of the cemented TKAs. Revision was performed for infection in 1 hybrid TKA. The hybrid group demonstrated a 7 years survival rate of 93% for all-cause failures and 94% for aseptic loosening. No significant difference in survivorship was seen between the groups for all-cause failures or aseptic failures. Conclusions: Hybrid TKA yields similar intermediate-term results and survival rates as fully cemented total knee arthroplasty and remains a viable option in knee joint replacement surgery.

Keywords: hybrid, survival rate, total knee arthroplasty, orthopaedic surgery

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Authors: A. Almurshedi, M. Atherton, C. Mares, T. Stolarski, M. Miyatake

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Transportation and handling of delicate and lightweight objects is currently a significant issue in some industries. Two common contactless movement prototype designs, ultrasonic transducer design and vibrating plate design, are compared. Both designs are based on the method of squeeze-film levitation, and this study aims to identify the limitations, and challenges of each. The designs are evaluated in terms of levitation capabilities, and characteristics. To this end, theoretical and experimental explorations are made. It is demonstrated that the ultrasonic transducer prototype design is better suited to the terms of levitation capabilities. However, the design has some operating and mechanical designing difficulties. For making accurate industrial products in micro-fabrication and nanotechnology contexts, such as semiconductor silicon wafers, micro-components and integrated circuits, non-contact oil-free, ultra-precision and low wear transport along the production line is crucial for enabling. One of the designs (design A) is called the ultrasonic chuck, for which an ultrasonic transducer (Langevin, FBI 28452 HS) comprises the main part. Whereas the other (design B), is a vibrating plate design, which consists of a plain rectangular plate made of Aluminium firmly fastened at both ends. The size of the rectangular plate is 200x100x2 mm. In addition, four rounded piezoelectric actuators of size 28 mm diameter with 0.5 mm thickness are glued to the underside of the plate. The vibrating plate is clamped at both ends in the horizontal plane through a steel supporting structure. In addition, the dynamic of levitation using the designs (A and B) has been investigated based on the squeeze film levitation (SFL). The input apparatus that is used with designs consist of a sine wave signal generator connected to an amplifier type ENP-1-1U (Echo Electronics). The latter has to be utilised to magnify the sine wave voltage that is produced by the signal generator. The measurements of the maximum levitation for three different semiconductor wafers of weights 52, 70 and 88 [g] for design A are 240, 205 and 187 [um], respectively. Whereas the physical results show that the average separation distance for a disk of 5 [g] weight for design B reaches 70 [um]. By using the methodology of squeeze film levitation, it is possible to hold an object in a non-contact manner. The analyses of the investigation outcomes signify that the non-contact levitation of design A provides more improvement than design B. However, design A is more complicated than design B in terms of its manufacturing. In order to identify an adequate non-contact SFL design, a comparison between two common such designs has been adopted for the current investigation. Specifically, the study will involve making comparisons in terms of the following issues: floating component geometries and material type constraints; final created pressure distributions; dangerous interactions with the surrounding space; working environment constraints; and complication and compactness of the mechanical design. Considering all these matters is essential for proficiently distinguish the better SFL design.

Keywords: ANSYS, floating, piezoelectric, squeeze-film

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Authors: Rebecca Dewfall, Mark Coleman, Vladimir Basabe

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Oxide scale growth is an inevitable byproduct of the high temperature processing of steel. Blister is a phenomenon that occurs due to oxide growth, where high temperatures result in the swelling of surface scale, producing a bubble-like feature. Blisters can subsequently become embedded in the steel substrate during hot rolling in the finishing mill. This rolled in scale defect causes havoc within industry, not only with wear on machinery but loss of customer satisfaction, poor surface finish, loss of material, and profit. Even though blister is a highly prevalent issue, there is still much that is not known or understood. The classic iron oxidation system is a complex multiphase system formed of wustite, magnetite, and hematite, producing multi-layered scales. Each phase will have independent properties such as thermal coefficients, growth rate, and mechanical properties, etc. Furthermore, each additional alloying element will have different affinities for oxygen and different mobilities in the oxide phases so that oxide morphologies are specific to alloy chemistry. Therefore, blister regimes can be unique to each steel grade resulting in a diverse range of formation mechanisms. Laboratory conditions were selected to simulate industrial hot rolling with temperature ranges approximate to the formation of secondary and tertiary scales in the finishing mills. Samples with composition: 0.15Wt% C, 0.1Wt% Si, 0.86Wt% Mn, 0.036Wt% Al, and 0.028Wt% Cr, were oxidised in a thermo-gravimetric analyser (TGA), with an air velocity of 10litresmin-1, at temperaturesof 800°C, 850°C, 900°C, 1000°C, 1100°C, and 1200°C respectively. Samples were held at temperature in an argon atmosphere for 10minutes, then oxidised in air for 600s, 60s, 30s, 15s, and 4s, respectively. Oxide morphology and Blisters were characterised using EBSD, WDX, nanoindentation, FIB, and FEG-SEM imaging. Blister was found to have both a nucleation and growth process. During nucleation, the scale detaches from the substrate and blisters after a very short period, roughly 10s. The steel substrate is then exposed inside of the blister and further oxidised in the reducing atmosphere of the blister, however, the atmosphere within the blister is highly dependent upon the porosity of the blister crown. The blister crown was found to be consistently between 35-40um for all heating regimes, which supports the theory that the blister inflates, and the oxide then subsequently grows underneath. Upon heating, two modes of blistering were identified. In Mode 1 it was ascertained that the stresses produced by oxide growth will increase with increasing oxide thickness. Therefore, in Mode 1 the incubation time for blister formation is shortened by increasing temperature. In Mode 2 increase in temperature will result in oxide with a high ductility and high oxide porosity. The high oxide ductility and/or porosity accommodates for the intrinsic stresses from oxide growth. Thus Mode 2 is the inverse of Mode 1, and incubation time is increased with temperature. A new phenomenon was reported whereby blister formed exclusively through cooling at elevated temperatures above mode 2.

Keywords: FEG-SEM, nucleation, oxide morphology, surface defect

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Authors: Shamsulhaq Amin

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Unbound granular materials (UGMs) are pivotal in ensuring long-term quality, especially in the layers under the surface of flexible pavements and other constructions. This study seeks to better understand the behavior of the UGMs by looking at popular models for predicting lasting deformation under various levels of stresses and load cycles. These models focus on variables such as the number of load cycles, stress levels, and features specific to materials and were evaluated on the basis of their ability to accurately predict outcomes. The study showed that these factors play a crucial role in how well the models work. Therefore, the research highlights the need to look at a wide range of stress situations to more accurately predict how much the UGMs bend or shift. The research looked at important factors, like how permanent deformation relates to the number of times a load is applied, how quickly this phenomenon happens, and the shakedown effect, in two different types of UGMs: granite and limestone. A detailed study was done over 100,000 load cycles, which provided deep insights into how these materials behave. In this study, a number of factors, such as the level of stress applied, the number of load cycles, the density of the material, and the moisture present were seen as the main factors affecting permanent deformation. It is vital to fully understand these elements for better designing pavements that last long and handle wear and tear. A series of laboratory tests were performed to evaluate the mechanical properties of materials and acquire model parameters. The testing included gradation tests, CBR tests, and Repeated load triaxial tests. The repeated load triaxial tests were crucial for studying the significant components that affect deformation. This test involved applying various stress levels to estimate model parameters. In addition, certain model parameters were established by regression analysis, and optimization was conducted to improve outcomes. Afterward, the material parameters that were acquired were used to construct graphs for each model. The graphs were subsequently compared to the outcomes obtained from the repeated load triaxial testing. Additionally, the models were evaluated to determine if they demonstrated the two inherent deformation behaviors of materials when subjected to repetitive load: the initial phase, post-compaction, and the second phase volumetric changes. In this study, using log-log graphs was key to making the complex data easier to understand. This method made the analysis clearer and helped make the findings easier to interpret, adding both precision and depth to the research. This research provides important insight into picking the right models for predicting how these materials will act under expected stress and load conditions. Moreover, it offers crucial information regarding the effect of load cycle and permanent deformation as well as the shakedown effect on granite and limestone UGMs.

Keywords: permanent deformation, unbound granular materials, load cycles, stress level

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Authors: Neeraj Vij, Amber Brennan, Jenni Winters, Hadi Salehi, Hamy Temkit, Emily Andrisevic, Mohan V. Belthur

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Idiopathic clubfoot is a common lower extremity deformity with an incidence of 1:500. The Ponseti Method is well known as the gold standard of treatment. However, there is limited functional data demonstrating correction of the clubfoot after treatment with the Ponseti method. The purpose of this study was to study the clinical and functional outcomes after the Ponseti method with the Clubfoot Disease-Specific Instrument (CDS) and pedobarography. This IRB-approved prospective study included patients aged 3-18 who were treated for idiopathic clubfoot with the Ponseti method between January 2008 and December 2018. Age-matched controls were identified through siblings of clubfoot patients and other community members. Treatment details were collected through a chart review of the included patients. Laboratory assessment included a physical exam, gait analysis, and pedobarography. The Pediatric Outcomes Data Collection Instrument and the Clubfoot Disease-Specific Instrument were also obtained on clubfoot patients (CF). The Wilcoxson rank-sum test was used to study differences between the CF patients and the typically developing (TD) patients. Statistical significance was set at p < 0.05. There were a total of 37 enrolled patients in our study. 21 were priorly treated for CF and 16 were TD. 94% of the CF patients had bilateral involvement. The age at the start of treatment was 29 days, the average total number of casts was seven to eight, and the average total number of casts after Achilles tenotomy was one. The reoccurrence rate was 25%, tenotomy was required in 94% of patients, and ≥1 tenotomy was required in 25% of patients. There were no significant differences between step length, step width, stride length, force-time integral, maximum peak pressure, foot progression angles, stance phase time, single-limb support time, double limb support time, and gait cycle time between children treated with the Ponseti method and typically developing children. The average post-treatment Pirani and Dimeglio scores were 5.50±0.58 and 15.29±1.58, respectively. The average post-treatment PODCI subscores were: Upper Extremity: 90.28, Transfers: 94.6, Sports: 86.81, Pain: 86.20, Happiness: 89.52, Global: 88.6. The average post-treatment Clubfoot Disease-Specific Instrument scores subscores were: Satisfaction: 73.93, Function: 80.32, Overall: 78.41. The Ponseti Method has a very high success rate and remains to be the gold standard in the treatment of idiopathic clubfoot. Timely management leads to good outcomes and a low need for repeated Achilles tenotomy. Children treated with the Ponseti method demonstrate good functional outcomes as measured through pedobarography. Pedobarography may have clinical utility in studying congenital foot deformities. Objective measures for hours of brace wear could represent an improvement in clubfoot care.

Keywords: functional outcomes, pediatric deformity, patient-reported outcomes, talipes equinovarus

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Authors: Rikke Lybæk, Tyge Kjær

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The Baltic Sea is suffering from nitrogen and phosphorus pollution, which causes eutrophication of the maritime environment and hence threatens the biodiversity of the Baltic Sea area. The intensified quantity of nutrients in the water has created challenges with the growth of seaweed being discarded on beaches around the sea. The cast seaweed has led to odor problems hampering the use of beach areas around the Bay of Køge in Denmark. This is the case in, e.g., Solrød Municipality, where recreational activities have been disrupted when cast seaweed pile up on the beach. Initiatives have, however, been introduced within the municipality to remove the cast seaweed from the beach and utilize it for renewable energy production at the nearby Solrød Biogas Plant, thus being co-digested with animal manure for power and heat production. This paper investigates which type of technology application’s have been applied in the effort to optimize the collection of cast seaweed, and will further reveal, how the seaweed has been pre-treated at the biogas plant to be utilized for energy production the most efficient, hereunder the challenges connected with the content of sand. Heavy metal contents in the seaweed and how it is managed will also be addressed, which is vital as the digestate is utilized as soil fertilizer on nearby farms. Finally, the paper will outline the energy production scheme connected to the use of seaweed as feedstock for biogas production, as well as the amount of nitrogen-rich fertilizer produced. The theoretical approach adopted in the paper relies on the thinking of Circular Bio-Economy, where biological materials are cascaded and re-circulated etc., to increase and extend their value and usability. The data for this research is collected as part of the EU Interreg project “Cluster On Anaerobic digestion, environmental Services, and nuTrients removAL” (COASTAL Biogas), 2014-2020. Data gathering consists of, e.g., interviews with relevant stakeholders connected to seaweed collection and operation of the biogas plant in Solrød Municipality. It further entails studies of progress and evaluation reports from the municipality, analysis of seaweed digestion results from scholars connected to the research, as well as studies of scientific literature to supplement the above. Besides this, observations and photo documentation have been applied in the field. This paper concludes, among others, that the seaweed harvester technology currently adopted is functional in the maritime environment close to the beachfront but inadequate in collecting seaweed directly on the beach. New technology hence needs to be developed to increase the efficiency of seaweed collection. It is further concluded that the amount of sand transported to Solrød Biogas Plant with the seaweed continues to pose challenges. The seaweed is pre-treated for sand in a receiving tank with a strong stirrer, washing off the sand, which ends at the bottom of the tank where collected. The seaweed is then chopped by a macerator and mixed with the other feedstock. The wear down of the receiving tank stirrer and the chopper are, however, significant, and new methods should be adopted.

Keywords: biogas, circular bio-economy, Denmark, maritime technology, cast seaweed, solrød municipality

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Authors: Giulia Colonna, Jocelyn Hoye, Bart de Laat, Gelsina Stanley, Jose Key, Alaaddin Ibrahimy, Sule Tinaz, Evan D. Morris

Abstract:

Parkinson’s disease (PD) is the second most common neurodegenerative disease and affects approximately 1% of the world’s population. Increasing evidence suggests that aerobic physical exercise can be beneficial in mitigating both motor and non-motor symptoms of the disease. In a recent pilot study of the role of exercise on PD, we sought to confirm exercise intensity by monitoring heart rate (HR). For this purpose, we asked participants to wear a chest strap heart rate monitor (Polar Electro Oy, Kempele). The device sometimes proved uncomfortable. Looking forward to larger clinical trials, it would be convenient to employ a more comfortable and user friendly device. The Fitbit Charge 4 (Fitbit Inc) is a potentially comfortable, user-friendly solution since it is a wrist-worn heart rate monitor. Polar H10 has been used in large trials, and for our purposes, we treated it as the gold standard for the beat-to-beat period (R-R interval) assessment. In previous literature, it has been shown that Fitbit Charge 4 has comparable accuracy to Polar H10 in healthy subjects. It has yet to be determined if the Fitbit is as accurate as the Polar H10 in subjects with PD or in clinical populations, generally. Goal: To compare the Fitbit Charge 4 to the Polar H10 for monitoring HR in PD subjects engaging in an intensive exercise program. Methods: A total of 596 exercise sessions from 11 subjects (6 males) were collected simultaneously by both devices. Subjects with early-stage PD (Hoehn & Yahr <=2) were enrolled in a 6 months exercise training program designed for PD patients. Subjects participated in 3 one-hour exercise sessions per week. They wore both Fitbit and Polar H10 during each session. Sessions included rest, warm-up, intensive exercise, and cool-down periods. We calculated the bias in the HR via Fitbit under rest (5min) and intensive exercise (20min) by comparing the mean HR during each of the periods to the respective means measured by the Polar (HRFitbit – HRPolar). We also measured the sensitivity and specificity of Fitbit for detecting HRs that exceed the threshold for intensive exercise, defined as 70% of an individual’s theoretical maximum HR. Different types of correlation between the two devices were investigated. Results: The mean bias was 1.68 bpm at rest and 6.29 bpm during high intensity exercise, with an overestimation by Fitbit in both conditions. The mean bias of Fitbit across both rest and intensive exercise periods was 3.98 bpm. The sensitivity of the device in identifying high intensity exercise sessions was 97.14 %. The correlation between the two devices was non-linear, suggesting a saturation tendency of Fitbit to saturate at high values of HR. Conclusion: The performance of Fitbit Charge 4 is comparable to Polar H10 for assessing exercise intensity in a cohort of PD subjects. The device should be considered a reasonable replacement for the more cumbersome chest strap technology in future similar studies of clinical populations.

Keywords: fitbit, heart rate measurements, parkinson’s disease, wrist-wearable devices

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Authors: Celine Shi Ying Lee, Jong Jian Lee

Abstract:

Background: Infectious keratitis is one of the leading causes of blindness worldwide. Prompt treatment with effective medication will control the infection early, preventing corneal scarring and visual loss. fluoroquinolones ophthalmic medication is used because of its broad-spectrum properties, potency, good intraocular penetration, and low toxicity. The study aims to evaluate the treatment outcome of corneal ulcers using Levofloxacin 1.5% ophthalmic solution (LVFX) with adjuvant oral ciprofloxacin when indicated and apply this treatment strategy in primary health care as first-line treatment. Methods: Patients with infective corneal ulcer treated in an eye center were recruited. Inclusion criteria includes Corneal infection consistent with bacterial keratitis, single or multiple small corneal ulcers. Treatment regime: LVFX hourly for the first 2 days, 2 hourly from the 3rd day, and 3 hourly on the 5th day of review. Adjuvant oral ciprofloxacin 500mg BD was administered for 5 days if there were multiple corneal ulcers or when the location of the cornea ulcer was central or paracentral. Results: 47 subjects were recruited. There were 16 (34%) males and 31 (66%) females. 40 subjects (85%) were contact lens (CL) related to corneal ulcer, and 7 subjects (15%) were non-contact lens related. 42 subjects (89%) presented with one ulcer, of which 20 of them (48%) needed adjuvant therapy. 5 subjects presented with 2 or 3 ulcers, of which 3 needed adjuvant therapy. A total of 23 subjects (49%) was given adjuvant therapy (oral ciprofloxacin 500mg BD for 5 days).21 of them (91%) were CL related. All subjects recovered fully, and the average duration of treatment was 3.7 days, with 49% of the subjects resolved on the 3rd day, 38% on the 5thday of and 13% on the 7thday. All subjects showed symptoms of relief of pain, light-sensitivity, and redness on the 3rd day with full visual recovery post-treatment. No adverse drug reactions were recorded. Conclusion: Our treatment regime demonstrated good clinical outcome as first-line treatment for corneal ulcers. A corneal ulcer is a common eye condition in Singapore, mainly due to CL wear. Pseudomonas aeruginosa is the most frequent and potentially sight-threatening pathogen involved in CL related corneal ulcer. Coagulase-negative Staphylococci, Staphylococcus aureus, and Streptococcus Pneumoniae were seen in non-CL users. All these bacteria exhibit good sensitivity rates to ciprofloxacin and levofloxacin. It is therefore logical in our study to use LVFX Eyedrops and adjuvant ciprofloxacin oral antibiotics when indicated as first line treatment for most corneal ulcers. Our study of patients, both CL related and non-CL related, have shown good clinical response and full recovery using the above treatment strategy. There was also a full restoration of visual acuity in all the patients. Eye-trained primary Healthcare practitioners can consider adopting this treatment strategy as first line treatment in patients with corneal ulcers. This is relevant during the COVID pandemic, where hospitals are overwhelmed with patients and in regions with limited access to specialist eye care. This strategy would enable early treatment with better clinical outcome.

Keywords: corneal ulcer, levofloxacin hydrate, treatment strategy, ciprofloxacin

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Authors: Bing Chen, Xiang Ni, Eric Li

Abstract:

With the population ageing, the number of patients suffering from chronic diseases is increasing, among which stroke is a high incidence for the elderly. In addition, there is a gradual increase in the number of patients with orthopedic or neurological conditions such as spinal cord injuries, nerve injuries, and other knee injuries. These diseases are chronic, with high recurrence and complications, and normal walking is difficult for such patients. Nowadays, robotic knee exoskeletons have been developed for individuals with knee impairments. However, the currently available robotic knee exoskeletons are generally developed with heavyweight, which makes the patients uncomfortable to wear, prone to wearing fatigue, shortening the wearing time, and reducing the efficiency of exoskeletons. Some lightweight materials, such as carbon fiber and titanium alloy, have been used for the development of robotic knee exoskeletons. However, this increases the cost of the exoskeletons. This paper illustrates the design of a new ultra-light and ultra-stiff truss type of lattice structure. The lattice structures are arranged in a fan shape, which can fit well with circular arc surfaces such as circular holes, and it can be utilized in the design of rods, brackets, and other parts of a robotic knee exoskeleton to reduce the weight. The metamaterial is formed by continuous arrangement and combination of small truss structure unit cells, which changes the diameter of the pillar section, geometrical size, and relative density of each unit cell. It can be made quickly through additive manufacturing techniques such as metal 3D printing. The unit cell of the truss structure is small, and the machined parts of the robotic knee exoskeleton, such as connectors, rods, and bearing brackets, can be filled and replaced by gradient arrangement and non-uniform distribution. Under the condition of satisfying the mechanical properties of the robotic knee exoskeleton, the weight of the exoskeleton is reduced, and hence, the patient’s wearing fatigue is relaxed, and the wearing time of the exoskeleton is increased. Thus, the efficiency and wearing comfort, and safety of the exoskeleton can be improved. In this paper, a brief description of the hardware design of the prototype of the robotic knee exoskeleton is first presented. Next, the design of the ultra-light and ultra-stiff truss type of lattice structures is proposed, and the mechanical analysis of the single-cell unit is performed by establishing the theoretical model. Additionally, simulations are performed to evaluate the maximum stress-bearing capacity and compressive performance of the uniform arrangement and gradient arrangement of the cells. Finally, the static analysis is performed for the cell-filled rod and the unmodified rod, respectively, and the simulation results demonstrate the effectiveness and feasibility of the designed ultra-light and ultra-stiff truss type of lattice structures. In future studies, experiments will be conducted to further evaluate the performance of the designed lattice structures.

Keywords: additive manufacturing, lattice structures, metamaterial, robotic knee exoskeleton

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