Search results for: mechanical low back pain

Authors: Sang-Myung Jung, Jeong Hyun Ju, Gwang Heum Yoon, Hwa Sung Shin

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Central nervous system (CNS) consists of neuronal cell and supporting cells. Astrocytes are the most common supporting cells and play roles in metabolism between neurons and blood vessel. For this function, engineered astrocytes have been studied as a therapeutic source for CNS injury. In neural tissue engineering, nanofiber has been suggested as an effective scaffold for providing structure and mechanical properties influencing physiology. Cellulose acetate (CA) has been investigated for material to fabricate scaffold because of its biocompatibility, biodegradability and fine thermal stability. In this research, CA nanofiber was modified via heat treatment and its effect on astrocyte activity was evaluated. Adhesion and viability of astrocyte were increased in proportion to stiffness. Additionally, expression of GFAP, a marker of astrocyte activation, was increased via stiffness of scaffold. This research suggests a simple modification method to change stiffness of CA nanofiber and shows cellular behavior affecting stiffness of three-dimensional scaffold independently. For the results, we highlight that the stiffness is a factor to regulate astrocyte activity.

Keywords: astrocyte, cellulose acetate, cell therapy, stiffness of scaffold

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Authors: A. Alvaredo , R. Guzman De Villoria, P. Castell, Juan P. Fernandez-Blazquez

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Since graphene was discovered in 2004, has been considered as superb material, due to its outstanding mechanical, electrical and thermal properties. Graphene has been incorporated as reinforcement in several high performance polymers in order to obtain a good balance of properties and to get new properties as thermal or electric conductivity. As well known, the properties of semicrystalline polymer and its composites depends heavily on degree of crystallinity. In this context, our research group has studied the crystallization behavior from amorphous state of PEEK/GNP composites. The monitoring of cold crystallization processes studied by time-resolved simultaneous wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS). These techniques allowed to get an extremely relevant information about the evolution of the morphology of the PEEK/GNP composites. In addition, the thermal evolution of cold crystallization was followed by differential scanning calorimetry (DSC) as well. The experimental results showed changes in crystallization kinetics and c parameter unit cell when adding graphene. The main aim of this work is to produce PEEK/GNP composites and characterize their morphology, unit cell parameters and crystallization kinetic.

Keywords: PEEK, graphene, synchrotron, cold crystallization

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Authors: Sanjay Ranade

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Traditional film theory assumes the cinema audience in a darkened room where cinema is projected on to a white screen, and the audience suspends their sense of reality. Shifts in audiences due to changes in cultural tastes or trends have been studied for decades. In the past two decades, however, the audience, especially the youth, has shifted to digital media for the consumption of cinema. As a result, not only are audiences watching cinema on different devices, they are also consuming cinema in places and ways never imagined before. Public transport often crowded to the brim with a lot of ambient content, and a variety of workplaces have become sites for cinema viewing. Cinema is watched piecemeal and at different times of the day. Audiences use devices such as mobile phones and tablets to watch cinema. The cinema viewing experience is getting redesigned by the user. The emerging design allows the spectator to not only consume images and narratives but also produce, reproduce, and manipulate existing images and narratives, thereby participating in the process and influencing it. Spectatorship studies stress on the importance of subjectivity when dealing with the structure of the film text and the cultural and psychological implications in the engagement between the spectator and the film text. Indian cinema has been booming and contributing to global movie production significantly. In 2005 film production was 1000 films a year and doubled to 2000 by 2016. Digital technology helped push this growth in 2012. Film studies in India have had a decided Euro-American bias. The studies have chiefly analysed the content for ideological leanings or myth or as reflections of society, societal changes, or articulation of identity or presented retrospectives of directors, actors, music directors, etc. The one factor relegated to the background has been the spectator. If they have been addressed, they are treated as a collective of class or gender. India has a performative tradition going back several centuries. How Indians receive cinema is an important aspect to study with respect to film studies. This exploratory and descriptive study looked at 162 young media students studying cinema at the undergraduate and postgraduate levels. The students, speaking as many as 20 languages amongst them, were drawn from across the country’s media schools. The study looked at nine film societies registered with the Federation of Film Societies of India. A structured questionnaire was made and distributed online through media teachers for the students. The film societies were approached through the regional office of the FFSI in Mumbai. Lastly, group discussions were held in Mumbai with students and teachers of media. A group consisted of between five and twelve student participants, along with one or two teachers. All the respondents looked at themselves as spectators and shared their experiences of spectators of cinema, providing a very rich insight into Indian conditions of viewing cinema and challenges for cinema ahead.

Keywords: audience, digital, film studies, reception, reception spectatorship

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Authors: Soumya Rajan

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While delving into the heart of any organization, the structural pre-requisites which form the framework of its system, allures and sometimes invokes great interest. In an attempt to understand the ecosystem of Knowledge that existed in organizations with diverse ownership and legal blueprints, Cooperative Societies, which form a crucial part of the neo-liberal movement in India, was studied. The exploration surprisingly led to the re-designing of at least a set of premises of the researcher on the drivers of engagement in an otherwise structured trade environment. The liberal organizational structure of Cooperative Societies has been empowered with certain terminologies: Voluntary, Democratic, Equality and Distributive Justice. To condense in Hubert Calvert’ words, ‘Co-operation is a form of organization wherein persons voluntarily associated together as human beings on the basis of equality for the promotion of the economic interest of themselves.’ In India, largely the institutions which work under this principle is registered under Cooperative Societies Act of the Central or State laws. A Worker Cooperative Society which originated as a movement in the state of Kerala and spread its wings across the country - Indian Coffee House was chosen as the enterprise for further inquiry for it being a living example and a highly successful working model in the designated space. The exploratory study reached out to employees and key stakeholders of Indian Coffee House to understand the nuances of the structure and the scope it provides for engagement. The key questions which formed shape in the mind of researcher while engaging in the inquiry were: How has the organization sustained despite its principle of accepting employees with no skills into employment and later training and empowering them? How can a system which has pre-independence and post-independence (independence here means the colonial independence from Great Britain) existence seek to engage employees within the premise of equality? How was the value of socialism ingrained in a commercial enterprise which has a turnover of several hundreds of Crores each year? How did the vision of a flat structure, way back in the 1940’s find its way into the organizational structure and has continued to remain as the way of life? These questions were addressed by the Case study research that ensued and placing Knowledge as the key premise, the possibilities of engagement of the organization man was pictured. Understanding that although the macro or holistic unit of analysis is the organization, it is pivotal to understand the structures and processes which best reflect on the actors. The embedded design which was adopted in this study delivered insights from the different stakeholder actors from diverse departments. While moving through variables which define and sometimes defy bounds in rationality, the study brought to light the inherent features of the organization structure and how it influences the actors who form a crucial part of the scheme of things. The research brought forth the key enablers for engagement and specifically explored the standpoint of knowledge in the larger structure of the Cooperative Society.

Keywords: knowledge, organizational structure, engagement, worker cooperative

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Authors: A. Ibáñez, A. Martínez, A. Sánchez, M. A. León

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This article is focused on the development of a series of biodegradable and eco-friendly masterbatches based on polylactic acid (PLA) filled with almond shell to study the influence of almond shell in the properties of injected biodegradable parts. These innovative masterbatches have 20 wt % of the almond shell. Different treatments were carried out with sodium hydroxide (NaOH) and maleic anhydride (MA) to obtain better interfacial bonding between fibre and matrix. The masterbatches were produced by varying the fibre treatments (type of treatment, concentration and temperature). The masterbatches have been injected to obtain standardised test samples in order to study mechanical properties. The results show that, the some of the treated fibres present slightly higher flexural modulus and impact strength than untreated fibres. This study is part of a LIFE project (MASTALMOND) aimed to create and test at preindustrial level new coloured masterbatches based on biodegradable polymers and containing in its formulation a high percentage of almond shell, a natural waste material, which firstly will permit to cover technical requirements of two traditional industrial sectors: toy and furniture, although the results achieved could be extended to other industrial sectors.

Keywords: additivation, almond shell, biodegradable, masterbatch, PLA, injection moulding

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Authors: Pravin Gaikwad, Prakash Mahanwar

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The main objective of incorporating natural fibers such as Henequen microfibers (NF) into the High-Density Polyethylene (HDPE) polymer matrix is to reduce the cost and to enhance the mechanical as well as other properties. The Henequen microfibers were chopped manually to 5-7mm in length and added into the polymer matrix at the optimized concentration of 8 wt %. In order to facilitate the link between Henequen microfibers (NF) and HDPE matrix, coupling agent such as Glycidoxy (Epoxy) Functional Methoxy Silane (GPTS) at various concentrations from 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, and 1% by weight to the total fibers were added. The tensile strength of the composite increased marginally while % elongation at break of the composites decreased with increase in silane loading by wt %. Tensile modulus and stiffness observed increased at 0.9 wt % GPTS loading. Flexural as well as impact strength of the composite decreased with increase in GPTS loading by weight %. Dielectric strength of the composite also found increased marginally upto 0.5wt % silane loading and thereafter remained constant.

Keywords: Henequen microfibers (NF), polymer composites, HDPE, coupling agent, GPTS

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Authors: Sharifah Nabihah Syed Jaafar, Umar Adli Amran, Rasidi Roslan, Chia Chin Hua, Sarani Zakaria

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Bio-composites derived from plant fiber and bio-derived polymer, are likely more ecofriendly and demonstrate competitive performance with petroleum based. In this research, the green phenolic resin was used as a matrix and oil palm empty fruit bunch fiber (EFB) was used as filler. The matrix was synthesized from soda lignin, phenol and hydrochloric acid as a catalyst. The phenolic resin was synthesized via liquefaction and condensation to enhance the combination of phenol during the process. Later, the phenolic resin was mixed with EFB by using mechanical stirrer and was molded with hot press at 180 oC. In this research, the composites were prepared with EFB content of 5%, 10%, 15% and 20%. The samples that viewed under scanning electron microscopy (SEM) showed that the EFB filler remained embedded in the resin. From impact and hardness testing, samples 10% of EFB showed the optimum properties meanwhile sample 15% showed the optimum properties for flexural testing. Thermal stability of the composites was investigated using thermogravimetric (TGA) analysis and found that the weight loss and the activation energy (Ea) of the composites samples were decreased as the filler content increased.

Keywords: EFB, liquefaction, phenol formaldehyde, lignin

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Authors: Hai L. Tran

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In the digital age, evidence-based reporting is touted as a best practice for seeking the truth and keeping the public well-informed. Journalists are expected to rely on evidence to demonstrate the validity of a factual statement and lend credence to an individual account. Evidence can be obtained from various sources, and due to a rich supply of evidence types available, the definition of this important concept varies semantically. To promote clarity and understanding, it is necessary to break down the various types of evidence and categorize them in a more coherent, systematic way. There is a wide array of devices that digital journalists deploy as proof to back up or refute a truth claim. Evidence can take various formats, including verbal and visual materials. Verbal evidence encompasses quotes, soundbites, talking heads, testimonies, voice recordings, anecdotes, and statistics communicated through written or spoken language. There are instances where evidence is simply non-verbal, such as when natural sounds are provided without any verbalized words. On the other hand, other language-free items exhibited in photos, video footage, data visualizations, infographics, and illustrations can serve as visual evidence. Moreover, there are different sources from which evidence can be cited. Supporting materials, such as public or leaked records and documents, data, research studies, surveys, polls, or reports compiled by governments, organizations, and other entities, are frequently included as informational evidence. Proof can also come from human sources via interviews, recorded conversations, public and private gatherings, or press conferences. Expert opinions, eye-witness insights, insider observations, and official statements are some of the common examples of testimonial evidence. Digital journalism studies tend to make broad references when comparing qualitative versus quantitative forms of evidence. Meanwhile, limited efforts are being undertaken to distinguish between sister terms, such as “data,” “statistical,” and “base-rate” on one side of the spectrum and “narrative,” “anecdotal,” and “exemplar” on the other. The present study seeks to develop the evidence taxonomy, which classifies evidence through the quantitative-qualitative juxtaposition and in a hierarchical order from broad to specific. According to this scheme, data, statistics, and base rate belong to the quantitative evidence group, whereas narrative, anecdote, and exemplar fall into the qualitative evidence group. Subsequently, the taxonomical classification arranges data versus narrative at the top of the hierarchy of types of evidence, followed by statistics versus anecdote and base rate versus exemplar. This research reiterates the central role of evidence in how journalists describe and explain social phenomena and issues. By defining the various types of evidence and delineating their logical connections it helps remove a significant degree of conceptual inconsistency, ambiguity, and confusion in digital journalism studies.

Keywords: evidence, evidence forms, evidence types, taxonomy

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Authors: C. S. Paglia

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The deformation and the crystallization in a 7075-T651 friction stir weld, in particular for regions directly in contact with the mechanical action of the rotating probe, have been investigated by means of optical microscopy. The investigation enabled to identify regions of the weld differently affected by the deformation caused by the welding process. The highly deformed grains in the horizontal direction close to the plate margin were indicative of shear movements along the horizontal plane, while highly deformed grains along the plate margin in the vertical direction were indicative of vertical shear movements of opposite directions, which superimposed the shear movement along the horizontal plane. The vertical shear movements were not homogeneous through the plate thickness. The microstructure indicated that after the probe passes, the grain growth may take place under static conditions. The small grains microstructure of the nugget region, formed after the main dynamic recrystallization process, develops to an equiaxed microstructure. A material transport influenced by the rotating shoulder was also observed from the trailing to the advancing side of the weld.

Keywords: AA7075-T651, friction stir welding, deformation, crystallization

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Authors: Khatir Omar, Fekih Sidi Mohamed, Sahli Abderahmene, Benkhettou Abdelkader, Boudjemaa Ismail

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Advancements in technology have revolutionized healthcare, with notable impacts on auditory health. This study introduces an approach aimed at optimizing materials for middle ear prostheses to enhance auditory performance. We have developed a finite element (FE) model of the ear incorporating a pure titanium TORP prosthesis, validated against experimental data. Subsequently, we applied the Functionally Graded Materials (FGM) methodology, utilizing linear, exponential, and logarithmic degradation functions to modify prosthesis materials. Biocompatible materials suitable for auditory prostheses, including Stainless Steel, titanium, and Hydroxyapatite, were investigated. The findings indicate that combinations such as Stainless Steel with titanium and Hydroxyapatite offer improved outcomes compared to pure titanium and Hydroxyapatite ceramic in terms of both displacement and stress. Additionally, personalized prostheses tailored to individual patient needs are feasible, underscoring the potential for further advancements in auditory healthcare.

Keywords: middle ear, prosthesis, ossicles, FGM, vibration analysis, finite-element method

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Authors: Jeffrey A. Humenik

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Environmental, Limited Liability Corporation (EMR) provided civil construction services to the U.S. Army Corps of Engineers, Kansas City District, for the placement of a protective riprap blanket on the west bank of the Smoky Hill River, construction of 2 shore abutments and the construction of a 140 foot long sill wall spanning the Smoky Hill River in Salina, Kansas. The purpose of the project was to protect the riverbank from erosion and hold back water to a specified elevation, creating a pool to ensure adequate water intake for the municipal water supply. Geotextile matting and riprap were installed for streambank erosion protection. An inflatable bladder (AquaDam®) was designed to the specific river dimension and installed to divert the river and allow for dewatering during the construction of the sill walls and cofferdam. AquaDam® consists of water filled polyethylene tubes to create aqua barriers and divert water flow or prevent flooding. A challenge of the project was the fact that 100% of the sill wall was constructed within an active river channel. The threat of flooding of the work area, damage to the aqua dam by debris, and potential difficulty of water removal presented a unique set of challenges to the construction team. Upon completion of the West Sill Wall, floating debris punctured the AquaDam®. The manufacturing and delivery of a new AquaDam® would delay project completion by at least 6 weeks. To keep the project ahead of schedule, the decision was made to construct an earthen cofferdam reinforced with rip rap for the construction of the East Abutment and East Sill Wall section. During construction of the west sill wall section, a deep scour hole was encountered in the wall alignment that prevented EMR from using the natural rock formation as a concrete form for the lower section of the sill wall. A formwork system was constructed, that allowed the west sill wall section to be placed in two horizontal lifts of concrete poured on separate occasions. The first sectional lift was poured to fill in the scour hole and act as a footing for the second sectional lift. Concrete wall forms were set on the first lift and anchored to the surrounding riverbed in a manner that the second lift was poured in a similar fashion as a basement wall. EMR’s timely decision to keep the project moving toward completion in the face of changing conditions enabled project completion two (2) months ahead of schedule. The use of inflatable bladders is an effective and cost-efficient technology to divert river flow during construction. However, a secondary plan should be part of project design in the event debris transported by river punctures or damages the bladders.

Keywords: abutment, AquaDam®, riverbed, scour

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Authors: Luciano Tarantino

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Gas gangrene is a rare, severe infection with a very high mortality rate caused by Clostridium species. The infection causes a non-suppurative localized producing gas lesion from which harmful toxins that impair the inflammatory response cause vessel damage and multiple organ failure. Gas gangrene of the liver is very rare and develops suddenly, often as a complication of abdominal surgery and liver transplantation. The present paper deals with a case of gas gangrene of the liver that occurred after percutaneous MW ablation of hepatocellular carcinoma, resulting in progressive liver necrosis and multi-organ failure in spite of specific antibiotics administration. The patient was successfully treated with percutaneous Radiofrequency ablation. Case report: Female, 76 years old, Child A class cirrhosis, treated with synchronous insertion of 3 MW antennae for large HCC (5.5 cm) in the VIII segment. 24 hours after treatment, the patient was asymptomatic and left the hospital . 2 days later, she complained of fever, weakness, abdominal swelling, and pain. Abdominal US detected a 2.3 cm in size gas-containing area, eccentric within the large (7 cm) ablated area. The patient was promptly hospitalized with the diagnosis of anaerobic liver abscess and started antibiotic therapy with Imipenem/cilastatine+metronidazole+teicoplanine. On the fourth day, the patient was moved to the ICU because of dyspnea, congestive heart failure, atrial fibrillation, right pleural effusion, ascites, and renal failure. Blood tests demonstrated severe leukopenia and neutropenia, anemia, increased creatinine and blood nitrogen, high-level FDP, and high INR. Blood cultures were negative. At US, unenhanced CT, and CEUS, a progressive enlargement of the infected liver lesion was observed. Percutaneous drainage was attempted, but only drops of non-suppurative brownish material could be obtained. Pleural and peritoneal drainages gave serosanguineous muddy fluid. The Surgeon and the Anesthesiologist excluded any indication of surgical resection because of the high perioperative mortality risk. Therefore, we asked for the informed consent of the patient and her relatives to treat the gangrenous liver lesion by percutaneous Ablation. Under conscious sedation, percutaneous RFA of GG was performed by double insertion of 3 cool-tip needles (Covidien LDT, USA ) into the infected area. The procedure was well tolerated by the patient. A dramatic improvement in the patient's condition was observed in the subsequent 24 hours and thereafter. Fever and dyspnea disappeared. Normalization of blood tests, including creatinine, was observed within 4 days. Heart performance improved, 10 days after the RFA the patient left the hospital and was followed-up with weekly as an outpatient for 2 months and every two months thereafter. At 18 months follow-up, the patient is well compensated (Child-Pugh class B7), without any peritoneal or pleural effusion and without any HCC recurrence at imaging (US every 3 months, CT every 6 months). Percutaneous RFA could be a valuable therapy of focal GG of the liver in patients non-responder to antibiotics and when surgery and liver transplantation are not feasible. A fast and early indication is needed in case of rapid worsening of patient's conditions.

Keywords: liver tumor ablation, interventional ultrasound, liver infection, gas gangrene, radiofrequency ablation

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Authors: M. Akhondizadeh, Mohsen Khajoei, Mojtaba Khajoei

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The purpose of the present work was the design of a towing machine which was decided to be manufactured by Arman Gohar-e-Sirjan company in the Gol-e-Gohar iron ore complex in Iran. The load analysis has been conducted to determine the static and dynamic loads at the critical conditions. The inertial forces due to the velocity increment and road bump have been considered in load evaluation. The form of loading of the present machine is hauling and/or conveying the mineral machines on the mini ramp. Several stages of these forms of loading, from the initial touch of the tow and carried machine to the final position, have been assessed to determine the critical state. The stress analysis has been performed by the ANSYS software. Several geometries for the main load-carrying elements have been analyzed to have the optimum design by the minimum weight of the structure. Finally, a structure with a total weight of 38 tons has been designed with a static load-carrying capacity of 80 tons by considering the 40 tons additional capacity for dynamic effects. The stress analysis for 120 tons load gives the minimum safety factor of 1.18.

Keywords: mechanical design, stress analysis, tow structure, dynamic load, static load

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Authors: MohammadSadegh SaeediFakher, Jafar Rouzegar, Hassan Assaee

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In this research, mechanical behavior and energy absorption capacity of empty and rubber-filled brazen circular tubes under quasi-static axial loading are investigated, experimentally. The brazen tubes were cut out of commercially available brazen circular tubes with the same length and diameter. Some of the specimens were filled with rubbers with three different shores and also, an empty tube was prepared. The specimens were axially compressed between two rigid plates in a quasi-static process using a Zwick testing machine. Load-displacement diagrams and energy absorption of the tested tubes were extracted from experimental data. The results show that filling the brazen tubes with rubber causes those to absorb more energy and the energy absorption of specimens are increased by increasing the shore of rubbers. In comparison to the empty tube, the first fold for the rubber-filled tubes occurs at lower load and it can be concluded that the rubber-filled tubes are better energy absorbers than the empty tubes. Also, in contrast with the empty tubes, the tubes that were filled with lower rubber shore deform asymmetrically.

Keywords: axial compression, quasi-static loading, folding, energy absorbers, rubber-filled tubes

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Authors: Rui Zhao, Dongxu Zhang, Min Wan

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Composite materials are widely used in the fields of aviation, aerospace, and transportation due to their lightweight and high strength. Functionalization of composite structures is a hot topic in the future development of composite materials. This article proposed a polyimide-resin based composite material with a sensing function. This material can serve as a sensor to achieve deformation monitoring of metal sheets in room temperature environments. In the deformation process of metal sheets, the slope of the linear fitting line for the corresponding material resistance change rate is different in the elastic stage and the plastic strengthening stage. Therefore, the slope of the material resistance change rate can be used to characterize the deformation stage of the metal sheet. In addition, the resistance change rate of the material exhibited a good negative linear relationship with temperature in a high-temperature environment, and the determination coefficient of the linear fitting line for the change rate of material resistance in the range of 520-650℃ was 0.99. These results indicate that the material has the potential to be applied in the monitoring of mechanical properties of structural materials and temperature monitoring of high-temperature environments.

Keywords: polyimide, composite, sensing, resistance change rate

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Authors: Awni Alkhazaleh

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Latent heat storage using Phase Change Materials (PCMs) has attracted growing attention recently in the renewable energy utilization and building energy efficiency. Paraffin (PA) of low melting temperature, which is close to human comfort temperature in the range of 24-28 °C has been considered to be used in building applications. A form-stable composite Paraffin/Expanded perlite (PA-EP) has been prepared by retaining PA into porous particles of EP. DSC (Differential scanning calorimeter) is used to measure the thermal properties of PA in the form-stable composite with/without building materials. TGA (Thermal gravimetric analysis) shows that the composite is thermally stable. SEM (Scanning electron microscope) demonstrates that the layer structure of the EP particles is uniformly absorbed by PA. The mechanical properties in flexural mode have been discussed. The thermal energy storage performance has been evaluated using a small test room (100 mm ×100 mm ×100 mm) with thickness 10 mm. The flammability test of modified sample has been discussed using a cone calorimeter. The results confirm that the form-stable composite PA has the function of reducing building energy consumption.

Keywords: flammability, latent heat storage, paraffin, plasterboard

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Authors: Severino Machingambi

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Most academics entering Higher education as lecturers in South Africa do not have qualifications in Education or teaching. This creates serious problems since they are not sufficiently equipped with pedagogical approaches and theories that inform their facilitation of learning strategies. This, arguably, is one of the reasons why higher education institutions are experiencing high student failure rate. In order to mitigate this problem, it is critical that higher education institutions devise internal academic staff development programmes to capacitate academics with pedagogical skills and competencies so as to enhance the quality of student learning. This paper reported on how the Teaching and Learning Development Centre of a university used design-based research methodology to conceptualise and implement an academic staff development programme for new academics at a university of technology. This approach revolves around the designing, testing and refining of an educational intervention. Design-based research is an important methodology for understanding how, when, and why educational innovations work in practice. The need for a professional development course for academics arose due to the fact that most academics at the university did not have teaching qualifications and many of them were employed straight from industry with little understanding of pedagogical approaches. This paper examines three key aspects of the programme namely, the preliminary phase, the teaching experiment and the retrospective analysis. The preliminary phase is the stage in which the problem identification takes place. The problem that this research sought to address relates to the unsatisfactory academic performance of the majority of the students in the institution. It was therefore hypothesized that the problem could be dealt with by professionalising new academics through engagement in an academic staff development programme. The teaching experiment phase afforded researchers and participants in the programme the opportunity to test and refine the proposed intervention and the design principles upon which it was based. The teaching experiment phase revolved around the testing of the new academics professional development programme. This phase created a platform for researchers and academics in the programme to experiment with various activities and instructional strategies such as case studies, observations, discussions and portfolio building. The teaching experiment phase was followed by the retrospective analysis stage in which the research team looked back and tried to give a trustworthy account of the teaching/learning process that had taken place. A questionnaire and focus group discussions were used to collect data from participants that helped to evaluate the programme and its implementation. One of the findings of this study was that academics joining university really need an academic induction programme that inducts them into the discourse of teaching and learning. The study also revealed that existing academics can be placed on formal study programmes in which they acquire educational qualifications with a view to equip them with useful classroom discourses. The study, therefore, concludes that new and existing academics in universities should be supported through induction programmes and placement on formal studies in teaching and learning so that they are capacitated as facilitators of learning.

Keywords: academic staff, pedagogy, programme, staff development

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Authors: Sreekanth T. G., Kishorekumar S., Sowndhariya Kumar J., Karthick R., Shanmugasuriyan S.

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Composites are increasingly being used in industries due to their unique properties, such as high specific stiffness and specific strength, higher fatigue and wear resistances, and higher damage tolerance capability. Composites are prone to failures or damages that are difficult to identify, locate, and characterize due to their complex design features and complicated loading conditions. The lack of understanding of the damage mechanism of the composites leads to the uncertainties in the structural integrity and durability. Delamination is one of the most critical failure mechanisms in laminated composites because it progressively affects the mechanical performance of fiber-reinforced polymer composite structures over time. The identification and severity characterization of delamination in engineering fields such as the aviation industry is critical for both safety and economic concerns. The presence of delamination alters the vibration properties of composites, such as natural frequencies, mode shapes, and so on. In this study, numerical analysis and experimental analysis were performed on delaminated and non-delaminated glass fiber reinforced polymer (GFRP) plate, and the numerical and experimental analysis results were compared, and error percentage has been found out.

Keywords: composites, delamination, natural frequency, mode shapes

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Authors: Jun Wang, Chenglei Diao, Emanuele Pagone, Jialuo Ding, Stewart Williams

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As a crucial component in aircraft, landing gear systems are responsible for supporting the plane during parking, taxiing, takeoff, and landing. Given the need for high load-bearing capacity over extended periods, 300M ultra-high strength steel (UHSS) is often the material of choice for crafting these systems due to its exceptional strength, toughness, and fatigue resistance. In the quest for cost-effective and sustainable manufacturing solutions, Wire Arc Additive Manufacturing (WAAM) emerges as a promising alternative for fabricating 300M UHSS landing gears. This is due to its advantages in near-net-shape forming of large components, cost-efficiency, and reduced lead times. Cranfield University has conducted an extensive preliminary study on WAAM 300M UHSS, covering feature deposition, interface analysis, and post-heat treatment. Both Gas Metal Arc (GMA) and Plasma Transferred Arc (PTA)-based WAAM methods were explored, revealing their feasibility for defect-free manufacturing. However, as-deposited 300M features showed lower strength but higher ductility compared to their forged counterparts. Subsequent post-heat treatments were effective in normalising the microstructure and mechanical properties, meeting qualification standards. A 300M UHSS landing gear demonstrator was successfully created using PTA-based WAAM, showcasing the method's precision and cost-effectiveness. The demonstrator, measuring Ф200mm x 700mm, was completed in 16 hours, using 7 kg of material at a deposition rate of 1.3kg/hr. This resulted in a significant reduction in the Buy-to-Fly (BTF) ratio compared to traditional manufacturing methods, further validating WAAM's potential for this application. A "cradle-to-gate" environmental impact assessment, which considers the cumulative effects from raw material extraction to customer shipment, has revealed promising outcomes. Utilising Wire Arc Additive Manufacturing (WAAM) for landing gear components significantly reduces the need for raw material extraction and refinement compared to traditional subtractive methods. This, in turn, lessens the burden on subsequent manufacturing processes, including heat treatment, machining, and transportation. Our estimates indicate that the carbon footprint of the component could be halved when switching from traditional machining to WAAM. Similar reductions are observed in embodied energy consumption and other environmental impact indicators, such as emissions to air, water, and land. Additionally, WAAM offers the unique advantage of part repair by redepositing only the necessary material, a capability not available through conventional methods. Our research shows that WAAM-based repairs can drastically reduce environmental impact, even when accounting for additional transportation for repairs. Consequently, WAAM emerges as a pivotal technology for reducing environmental impact in manufacturing, aiding the industry in its crucial and ambitious journey towards Net Zero. This study paves the way for transformative benefits across the aerospace industry, as we integrate manufacturing into a hybrid solution that offers substantial savings and access to more sustainable technologies for critical component production.

Keywords: WAAM, aircraft landing gear, microstructure, mechanical performance, life cycle assessment

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Authors: Harvinder Kaur

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Rayleigh–Ritz method is a broadly used classical method for the calculation of the natural vibration frequency of a structure in the second or higher order. Here it is used to construct a mathematical model of relative study of the thermal effect on free transverse vibrations of clamped (c-c-c-c type) visco-elastic rectangular plate with linearly and exponentially thickness variations respectively in two directions. Researchers in the field of Engineering always make an effort for better designs of mechanical structures. In-depth study of the vibration behavior of tapered plates with diverse thickness variation under high temperature would ultimately help to finalize the accurate design of a structure. The perfect tapered structure saves weight and as well as expenses. In the present paper, the comparison has been done for deflection and time period corresponding to the first two modes of vibrations of clamped plate for various values of aspect ratio, thermal constants, and taper constants of both the cases.

Keywords: Rayleigh-Ritz Method, tapered plates, transverse vibration, thermal constant, visco-elasticity

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Authors: Sylwia Wiewiorowska, Zbigniew Muskalski

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The article presents part of research on the development of nickel plated welding wire production technology, whose application will enable the elimination of the flaws of currently manufactured welding wires. The nickel plated welding wire will be distinguished by high quality, because the Ni layer which is deposited electrochemically onto it from acid baths is characterized by very good adhesion to the steel wire surface, while the ductile nickel well deforms plastically in the drawing process and the adhesion of the Ni layer increases in the drawing process due to the occurring process of diffusion between the Ni and the steel. The Ni layer obtained in the proposed technology, despite a smaller thickness than when the wire is coated with copper, is continuous and tight, thus ensuring high corrosion resistance, as well as unsusceptible to scaling, which should provide a product that meets requirements imposed by the market. The product will also reduce, to some extent, the amount of copper brought in to steel through recycling, while the wire coating nickel introduced to the weld in the welding process is expected, to a degree, to favorably influence its mechanical properties. The paper describes the tests of the process of nickel plating of f1.96 mm-diameter wires using various nickel plating baths with different process parameters.

Keywords: steel wire, properties, welding process, Ni layer

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Authors: Aouina Nabila Yasmina, Chaoui Zine El Abiddine

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This study presents a comprehensive investigation into the elastic mean free path (EMFP) of electrons colliding with pyrimidine, a precursor to the pyrimidine bases in DNA, employing the Screen Corrected Additivity Rule (SCAR) method. The SCAR method is introduced as a novel approach that combines classical and quantum mechanical principles to elucidate the interaction of electrons with pyrimidine. One of the most fundamental properties characterizing the propagation of a particle in the nuclear medium is its mean free path. Knowledge of the elastic mean free path is essential to accurately predict the effects of radiation on biological matter, as it contributes to the distances between collisions. Additionally, the mean free path plays a role in the interpretation of almost all experiments in which an excited electron moves through a solid. Pyrimidine, the precursor of the pyrimidine bases of DNA, has interesting physicochemical properties, which make it an interesting molecule to study from a fundamental point of view. These include a relatively large dipole polarizability and dipole moment and an electronic charge cloud with a significant spatial extension, which justifies its choice in this present study.

Keywords: elastic mean free path, elastic collision, pyrimidine, SCAR

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Authors: Mohammad Reza Zamani Kouhpanji

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This paper presents a MEMS/NEMS device for fatigue and fracture characterization of nanomaterials. This device can apply static loads, cyclic loads, and their combinations in nanomechanical experiments. It is based on the electromagnetic force induced between paired parallel wires carrying electrical currents. Using this concept, the actuator and sensor parts of the device were designed and analyzed while considering the practical limitations. Since the PWCC device only uses two wires for actuation part and sensing part, its fabrication process is extremely easier than the available MEMS/NEMS devices. The total gain and phase shift of the MEMS/NEMS device were calculated and investigated. Furthermore, the maximum gain and sensitivity of the MEMS/NEMS device were studied to demonstrate the capability and usability of the device for wide range of nanomaterials samples. This device can be readily integrated into SEM/TEM instruments to provide real time study of the mechanical behaviors of nanomaterials as well as their fatigue and fracture properties, softening or hardening behaviors, and initiation and propagation of nanocracks.

Keywords: sensors and actuators, MEMS/NEMS devices, fatigue and fracture nanomechanical testing device, static and cyclic nanomechanical testing device

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Authors: William Fuentes, Melany Gil

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Numerical simulations of offshore wind turbines (OWTs) in shallow waters demand sophisticated models considering the cyclic nature of the environmental loads. For the case of an OWT founded on sands, rapid loading may cause a reduction of the effective stress of the soil surrounding the structure. This eventually leads to its settlement, tilting, or other issues affecting its serviceability. In this work, a 3D FE model of an OWT founded on sand is constructed and analyzed. Cyclic loading with different histories is applied at certain points of the tower to simulate some environmental forces. The mechanical behavior of the soil is simulated through the recently proposed ISA-hypoplastic model for sands. The Intergranular Strain Anisotropy ISA can be interpreted as an enhancement of the intergranular strain theory, often used to extend hypoplastic formulations for the simulation of cyclic loading. In contrast to previous formulations, the proposed constitutive model introduces an elastic range for small strain amplitudes, includes the cyclic mobility effect and is able to capture the cyclic behavior of sands under a larger number of cycles. The model performance is carefully evaluated on the FE dynamic analysis of the OWT.

Keywords: offshore wind turbine, monopile, ISA, hypoplasticity

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Authors: Rupesh S. Gundewar, Kanchan C. Khare

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Runoff contribution from urban areas is generally from manmade structures and few natural contributors. The manmade structures are buildings; roads and other paved areas whereas natural contributors are groundwater and overland flows etc. Runoff alleviation is done by manmade as well as natural storages. Manmade storages are storage tanks or other storage structures such as soakways or soak pits which are more common in western and European countries. Natural storages are catchment slope, infiltration, catchment length, channel rerouting, drainage density, depression storage etc. A literature survey on the manmade and natural storages/inflow has presented percentage contribution of each individually. Sanders et.al. in their research have reported that a vegetation canopy reduces runoff by 7% to 12%. Nassif et el in their research have reported that catchment slope has an impact of 16% on bare standard soil and 24% on grassed soil on rainfall runoff. Infiltration being a pervious/impervious ratio dependent parameter is catchment specific. But a literature survey has presented a range of 15% to 30% loss of rainfall runoff in various catchment study areas. Catchment length and channel rerouting too play a considerable role in reduction of rainfall runoff. Ground infiltration inflow adds to the runoff where the groundwater table is very shallow and soil saturates even in a lower intensity storm. An approximate percent contribution through this inflow and surface inflow contributes to about 2% of total runoff volume. Considering the various contributing factors in runoff it has been observed during a literature survey that integrated modelling approach needs to be considered. The traditional storm water network models are able to predict to a fair/acceptable degree of accuracy provided no interaction with receiving water (river, sea, canal etc), ground infiltration, treatment works etc. are assumed. When such interactions are significant then it becomes difficult to reproduce the actual flood extent using the traditional discrete modelling approach. As a result the correct flooding situation is very rarely addressed accurately. Since the development of spatially distributed hydrologic model the predictions have become more accurate at the cost of requiring more accurate spatial information.The integrated approach provides a greater understanding of performance of the entire catchment. It enables to identify the source of flow in the system, understand how it is conveyed and also its impact on the receiving body. It also confirms important pain points, hydraulic controls and the source of flooding which could not be easily understood with discrete modelling approach. This also enables the decision makers to identify solutions which can be spread throughout the catchment rather than being concentrated at single point where the problem exists. Thus it can be concluded from the literature survey that the representation of urban details can be a key differentiator to the successful understanding of flooding issue. The intent of this study is to accurately predict the runoff from impermeable areas from urban area in India. A representative area has been selected for which data was available and predictions have been made which are corroborated with the actual measured data.

Keywords: runoff, urbanization, impermeable response, flooding

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Authors: J. Vyas, R. Kazys, J. Sestoke

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Air-coupled ultrasonic is the contactless ultrasonic measurement approach which has become widespread for material characterization in Aerospace industry. It is always essential for the requirement of lightest weight, without compromising the durability. To archive the requirements, composite materials are widely used. This paper yields analysis of the air-coupled ultrasonics for composite materials such as CFRP (Carbon Fibre Reinforced Polymer) and GLARE (Glass Fiber Metal Laminate) and honeycombs for the design of modern aircrafts. Laser vibrometry could be the key source of characterization for the aerospace components. The air-coupled ultrasonics fundamentals, including principles, working modes and transducer arrangements used for this purpose is also recounted in brief. The emphasis of this paper is to approach the developed NDT techniques based on the ultrasonic guided waves applications and the possibilities of use of laser vibrometry in different materials with non-contact measurement of guided waves. 3D assessment technique which employs the single point laser head using, automatic scanning relocation of the material to assess the mechanical displacement including pros and cons of the composite materials for aerospace applications with defects and delaminations.

Keywords: air-coupled ultrasonics, contactless measurement, laser interferometry, NDT, ultrasonic guided waves

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Authors: Sabrina Boutaleb, Kouider Halim Benrahou, François Schosseler, Abdelouahed Tounsi, El Abbas Adda Bedia

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The use of polyurethane in different areas becomes more frequent. This is due to significant advantages they have including their lightness and resistance. However, their use requires a mastery of their mechanical performance. We will present in this work, a COAPUR 6050 which can be used to develop composite materials. COAPUR 6050 is an associative polyurethane thickener allowing fine rheological adjustment of flat or semi-gloss paints. COAPUR 6050 is characterised by its thickening efficiency at low shear rate. It is a solvent-free liquid product. It promotes good paint pick up, while maintaining a low yield point after shearing, and consequently a good levelling. We will then determine its rheological behaviour experimentally using different annular gaps. The rheological properties of COAPUR 6050 were researched by rotational rheometer (Rheometer-Mars III) using different annular gaps. There is the influence of the size of the annular gap on the behaviour as well as on the rheological parameters of the COAPUR 6050. The rheological properties data of COAPUR 6050 were regressed by nonlinear regression method and their rheological models were established, are characterized by yield pseudoplastic model. In this case, it is essential to make a viscometric correction. The latter was developed and presented in the experimental results.

Keywords: COAPUR 6050, flow’s couette, polyurethane, rheological behaviours

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Authors: K. Sandjak, B. Tiliouine

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This article presents the main results of three-dimensional (3-D) numerical investigation of asphalt pavement structures behaviour using a coupled Finite Element-Mapped Infinite Element (FE-MIE) model. The validation and numerical performance of this model are assessed by confronting critical pavement responses with Burmister’s solution and FEM simulation results for multi-layered elastic structures. The coupled model is then efficiently utilised to perform 3-D simulations of a typical asphalt pavement structure in order to investigate the impact of two tire configurations (conventional dual and new generation wide-base tires) on critical pavement response parameters. The numerical results obtained show the effectiveness and the accuracy of the coupled (FE-MIE) model. In addition, the simulation results indicate that, compared with conventional dual tire assembly, single wide base tire caused slightly greater fatigue asphalt cracking and subgrade rutting potentials and can thus be utilised in view of its potential to provide numerous mechanical, economic, and environmental benefits.

Keywords: 3-D numerical investigation, asphalt pavements, dual and wide base tires, Infinite elements

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Authors: Kim Quy Le, Duan Fei, Jia Wei Chew, Jun Zeng, Maria Fabiola Leyva

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In line with the sustainable development goal, molded fiber products play important roles in reducing plastic-based packaging. To fabricate molded fiber products, besides using conventional meshing tools, 3D printing is employed to manufacture the molded fiber screen. 3D printing technique allows printing molded fiber screens with complex geometry, flexible in pore size and shape. The 3D printed molded fiber screens are in the progress of investigation to improve the de-watering efficiency, fiber collection, mechanical strength, etc. In addition, the fiber distribution on the screen is also necessary to access the quality of the screen. Besides using experimental methods to capture the fiber distribution on screen, simulation also offers using tools to access the uniformity of fiber. In this study, the fiber was simulated using the multi-sphere model to simulate the fibers. The interaction of the fibers was able to mimic by employing the discrete element method. The fiber distribution was captured and compared to the experiment. The simulation results were able to reveal the fiber deposition layer upon layer and explain the formation of uneven thickness on the tilted area of molded fiber screen.

Keywords: 3D printing, multi-jet fusion, molded fiber screen, discrete element method

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Authors: D.Rached, M.Rabah

Abstract:

First principles calculations are carried out to investigate the structural, electronic, and elastic properties of the utraincompressible materials, namely, noble metal carbide of Rhenium carbide (ReC) in four phases, the rocksalt (NaCl-B1), zinc blende (ZB-B2), the tungsten carbide(Bh) (WC), and the nickel arsenide (NiAs-B8).The ground state properties such as the equilibrium lattice constant, elastic constants, the bulk modulus its pressure derivate, and the hardness of ReC in these phases are systematically predicted by calculations from first–principles. The corresponding calculated bulk modulus is comparable with that of diamond, especially for the B8 –type rhenium carbide (ReC), the incompressibility along the c axis is demonstrated to exceed the linear incompressibility of diamond. Our calculations confirm in the nickel arsenide (B8) structure the ReC is found to be stable with a large bulk modulus B=440 GPa and the tungsten carbide (WC) structure becomes the most more favourable with to respect B3 and B1 structures, which ReC- WC is meta-stable. Furthermore, the highest bulk modulus values in the zinc blende (B3), rock salt (B1), tungsten carbide (WC), and the nickel arsenide (B8) structures (294GPa, 401GPa, 415GPa and 447 GPa, respectively) indicates that ReC is a hard material, and is superhard compound H(B8)= 36 GPa compared with the H(diamond)=96 GPa and H(c BN)=63.10 GPa.

Keywords: DFT, FP-LMTO, mechanical properties, elasticity, high pressure, thermodynamic properties, hard material

Procedia PDF Downloads 425