Search results for: high arches

Authors: Tong-Hsien Chow

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Background: Plantar pressure measurement is an effective method for assessing plantar loading and can be applied to evaluating movement performance of the foot. The purpose of this study is to explore the sprint athletes’ plantar loading characteristics and pain profiles in static standing. Methods: Experiments were undertaken on 80 first-division college sprint athletes and 85 healthy non-sprinters. ‘JC Mat’, the optical plantar pressure measurement was applied to examining the differences between both groups in the arch index (AI), three regional and six distinct sub-regional plantar pressure distributions (PPD), and footprint characteristics. Pain assessment and self-reported health status in sprint athletes were examined for evaluating their common pain areas. Results: Findings from the control group, the males’ AI fell into the normal range. Yet, the females’ AI was classified as the high-arch type. AI values of the sprint group were found to be significantly lower than the control group. PPD were higher at the medial metatarsal bone of both feet and the lateral heel of the right foot in the sprint group, the males in particular, whereas lower at the medial and lateral longitudinal arches of both feet. Footprint characteristics tended to support the results of the AI and PPD, and this reflected the corresponding pressure profiles. For the sprint athletes, the lateral knee joint and biceps femoris were the most common musculoskeletal pains. Conclusions: The sprint athletes’ AI were generally classified as high arches, and that their PPD were categorized between the features of runners and high-arched runners. These findings also correspond to the profiles of patellofemoral pain syndrome (PFPS)-related plantar pressure. The pain profiles appeared to correspond to the symptoms of high-arched runners and PFPS. The findings reflected upon the possible link between high arches and PFPS. The correlation between high-arched runners and PFPS development is worth further studies.

Keywords: sprint athletes, arch index, plantar pressure distributions, high arches, patellofemoral pain syndrome

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Authors: Mohamed M. El Gendy, Ibrahim A. El Arabi, Rafeek W. Abdel-Missih, Omar A. Kandil

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Nonlinear analysis is one of the most important design and safety tools in structural engineering. Based on the finite-element method, a geometrical and material nonlinear analysis of large span reinforced concrete arches is carried out considering soil-structure interaction. The concrete section details and reinforcement distribution are taken into account. The behavior of soil is considered via Winkler's and continuum models. A computer program (NARC II) is specially developed in order to follow the structural behavior of large span reinforced concrete arches up to failure. The results obtained by the proposed model are compared with available literature for verification. This work confirmed that the geometrical and material nonlinearities, as well as soil structure interaction, have considerable influence on the structural response of reinforced concrete arches.

Keywords: nonlinear analysis, reinforced concrete arched structure, soil-structure interaction, geotechnical engineering

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Authors: Amin Moradi, Maryam Moeini

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It is a widely held view that Ghiyath al-Din Jamshid-e-Kashani, also known as al-Kashi (1380-1429 CE), was the first who played a significant role in the interaction between mathematicians and architects by introducing theoretical knowledge in Islamic architecture. In academic discourses, geometric rules extracted from his splendid volume titled as Key of Arithmetic has uncritically believed by historians of architecture to contemplate the whole process of arch design all throughout the Islamic buildings. His theories tried to solve the fundamental problem of structural design and to understand what makes an Islamic structure safe or unsafe. As a result, al-Kashi arrived at the conclusion that a safe state of equilibrium is achieved through a specific geometry as a rule. This paper reassesses the stability of al-Kashi's systematized principal forms to evaluate the logic of his hypothesis with a special focus on large spans. Besides the empirical experiences of the author in masonry constructions, the finite element approach was proposed considering the current standards in order to get a better understanding of the validity of geometric rules proposed by al-Kashi for the equilibrium conditions of Islamic masonry arches and vaults. The state of damage of his reference arches under loading condition confirms beyond any doubt that his conclusion of the geometrical configuration measured through his treaties present some serious operational limits and do not go further than some individualized mathematical hypothesis. Therefore, the nature of his mathematical studies regarding Islamic arches is in complete contradiction with the practical knowledge of construction methodology.

Keywords: Jamshid al-Kashani, Islamic architecture, Islamic geometry, construction equilibrium, collapse mechanism

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Authors: Mitchell Gohnert

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This paper reviews some fundamental concepts of structural optimization, which is focused on the shape of the structure. Bending stresses produce high peak stresses at each face of the member, and therefore, substantially more material is required to resist bending. The shape of the structure has a profound effect on stress levels. Stress may be reduced dramatically by simply changing the shape to accommodate natural stress flow. The main objective of structural optimization is to direct the thrust line along the axis of the member. Optimal shapes include the catenary arch or dome, triangular shapes, and columns. If the natural flow of stress matches the shape of the structures, the most optimal shape is determined. Structures, however, must resist multiple load patterns. An optimal shape is still possible by ensuring that the thrust lines fall within the middle third of the member.

Keywords: optimization, natural structures, shells, catenary, domes, arches

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Authors: Raphaël Menard, Etienne Fayette, Paul Azzopardi

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This paper presents the method to generate the geometry of an actual glass canopy project in Rennes, France, by architect Bruno Gaudin, with aim to achieve the best structural efficiency possible using only quadrangle meshing. The paper includes equation of the translational surface generated, the level of accuracy in approximating the funicular shape and the method of constructive implementation.

Keywords: funicular shape, glass canopy, glass panels, lowered arches, mathematics, penalization, shell structure

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Authors: Amaia Martinez Martinez, Martin Turek, Carlos Ventura, Jay Drew

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This study aims to assess the seismic performance of arch and dome structural systems made from easy to assemble precast blocks of recycled concrete. These systems have been developed by Lock Block Ltd. Company from Vancouver, Canada, as an extension of their currently used retaining wall system. The characterization of the seismic behavior of these structures is performed by a combination of experimental static and dynamic testing, and analytical modeling. For the experimental testing, several tilt tests, as well as a program of shake table testing were undertaken using small scale arch models. A suite of earthquakes with different characteristics from important past events are chosen and scaled properly for the dynamic testing. Shake table testing applying the ground motions in just one direction (in the weak direction of the arch) and in the three directions were conducted and compared. The models were tested with increasing intensity until collapse occurred; which determines the failure level for each earthquake. Since the failure intensity varied with type of earthquake, a sensitivity analysis of the different parameters was performed, being impulses the dominant factor. For all cases, the arches exhibited the typical four-hinge failure mechanism, which was also shown in the analytical model. Experimental testing was also performed reinforcing the arches using a steel band over the structures anchored at both ends of the arch. The models were tested with different pretension levels. The bands were instrumented with strain gauges to measure the force produced by the shaking. These forces were used to develop engineering guidelines for the design of the reinforcement needed for these systems. In addition, an analytical discrete element model was created using 3DEC software. The blocks were designed as rigid blocks, assigning all the properties to the joints including also the contribution of the interlocking shear key between blocks. The model is calibrated to the experimental static tests and validated with the obtained results from the dynamic tests. Then the model can be used to scale up the results to the full scale structure and expanding it to different configurations and boundary conditions.

Keywords: arch, discrete element model, seismic assessment, shake-table testing

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Authors: Mitchell Gohnert, Ryan Bradley

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This paper reviews some fundamental concepts of structural optimization, which are based on the type of materials used in construction and the shape of the structure. The first step in structural optimization is to break down all internal forces in a structure into fundamental stresses, which are tensions and compressions. Knowing the stress patterns directs our selection of structural shapes and the most appropriate type of construction material. In our selection of materials, it is essential to understand all construction materials have flaws, or micro-cracks, which reduce the capacity of the material, especially when subjected to tensions. Because of material defects, many construction materials perform significantly better when subjected to compressive forces. Structures are also more efficient if bending moments are eliminated. Bending stresses produce high peak stresses at each face of the member, and therefore, substantially more material is required to resist bending. The shape of the structure also has a profound effect on stress levels. Stress may be reduced dramatically by simply changing the shape. Catenary, triangular and linear shapes are the fundamental structural forms to achieve optimal stress flow. If the natural flow of stress matches the shape of the structures, the most optimal shape is determined.

Keywords: arches, economy of stresses, material strength, optimization, shells

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Authors: Baharak Shakeri, Seyed Hashem Hosseini

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The weather in deserts is hot and dry in summers, and cold and dry in winters, and difference of temperature of nights and days sometimes reaches to 28°C. People of deserts have reached some solutions to cope with this climatic condition and to decrease its annoying features. Among these solutions are: constructing houses adjacent to each other, making tall walls, using mud brick and thatch cover, constructing domical arches, cellar, and wind catcher, which are together the devices to control the adversity of hot weather in summers and cold weather in winters. Using these solutions, the people of deserts have succeeded to make the best use with the least energy consumption, and to minimize the damage on the nature and environment, and in short, they are friends of the nature, which is a step toward the objectives of green buildings.

Keywords: desert house, green building, Iran, nature

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Authors: A. Zatir, A. Mokhtari, A. Foufa, S. Zatir

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The city of Oran, like any other region of northern Algeria, is subject to frequent seismic activity, the study presented in this work will be based on an analysis of urban and architectural context of the city of Oran before the date of the earthquake of 1790, and then try to deduce the differences between the old city before and after the earthquake. The analysis developed as a specific objective to tap into the seismic history of the city of Oran parallel to its urban history. The example of the citadel of Oran indicates that constructions presenting the site of the old citadel, may present elements of resistance for face to seismic effects. Removed in city observations of these structures, showed the ingenuity of the techniques used by the ancient builders, including the good performance of domes and arches in resistance to seismic forces.

Keywords: earthquake, citadel, performance, traditional techniques, constructions

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Authors: Donatello Cardone

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Shape memory alloys (SMAs) have great potential for use in the field of civil engineering. The author of this manuscript has been involved, since 1996, in several experimental and theoretical studies on the application of SMAs in structural engineering, within national and international research projects. This paper provides an overview of the main results achieved, including the conceptual design, implementation, and testing of different SMA-based devices, namely: (i) energy-dissipating braces for RC buildings, (ii) seismic isolation devices for buildings and bridges, (iii) smart tie-rods for arches and vaults and (iv) seismic restrainers for bridges. The main advantages of using SMA-based devices in the seismic protection of structures derive from the double-flag shape of their hysteresis loops, which implies three favourable features, i.e., self-centering capability, good energy dissipation capability, and high stiffness for small displacements. The main advantages of SMA-based units for steel tie-rods are associated with the thermal behaviour of superelastic SMAs, which is antagonistic compared to that of steel. This implies a strong reduction of force changes due to air temperature variations. Finally, SMA-based seismic restrainers proved to be effective in preventing bridge deck unseating and pounding.

Keywords: seismic protection of structures, shape memory alloys, structural engineering, steel tie-rods, seismic restrainers for bridges

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Authors: Nazih Ramadan, Manal Mohy-Eldine, Amani Hanoon, Alaa Shehab

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Background and Aims: The study of fingerprints is widely used in providing a clue regarding identity. Age and gender identification from fingerprints is an important step in forensic anthropology in order to minimize the list of suspects search. The aim of this study was to determine finger ridge density and patterns among Egyptians, and to estimate age and gender using ridge densities. Materials and Methods: This study was conducted on 177 randomly-selected healthy Egyptian subjects (90 males and 87 females). They were divided into three age groups; Group (a): from 6-< 12 years, group (b) from 12-< 18 years and group (c) ≥ 18 years. Bilateral digital prints, from every subject, were obtained by the inking procedure. Ridge count per 25 mm² was determined together with assessment of ridge pattern type. Statistical analysis was done with references to different age and sex groups. Results: There was a statistical significant difference in ridge density between the different age groups; where younger ages had significantly higher ridge density than older ages. Females proved to have significantly higher ridge density than males. Also, there was a statistically significant negative correlation between age and ridge density. Ulnar loops were the most frequent pattern among Egyptians then whorls then arches then radial loops. Finally, different regression models were constructed to estimate age and gender from fingerprints ridge density. Conclusion: fingerprint ridge density can be used to identify both age and sex of subjects. Further studies are recommended on different populations, larger samples or using different methods of fingerprint recording and finger ridge counting.

Keywords: age, sex identification, Egyptian population, fingerprints, ridge density

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Authors: Vishal Puri, Pradipta Chakrabortty, Swapan Majumdar

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Precast concrete construction is the most commonly used technique for a rapid construction. This technique is very frequently used in the developed countries. Different guidelines required to utilize the potential of prefabricated construction are still not available in the developing countries. This causes over dependence on in-situ construction procedure which further affects the quality, scheduling, and duration of construction. Also with the ever increasing costs of building materials and their negative impact on the environment it has become imperative to look out for alternate construction materials which are cheap and sustainable. Bamboo and fly ash are alternate construction materials having great potential in the construction industry. Thus there is a great need to develop prefabricated components by utilizing the potential of these materials. Bamboo reinforced beams, bamboo reinforced columns and bamboo arches as researched previously have shown great prospects for prefabricated construction industry. But, many other prefabricated components still need to be studied and widely tested before their utilization in the prefabricated construction industry. In the present study, authors have showcased prefabricated bamboo reinforced wall panel for the prefabricated construction industry. It presents a detailed methodology for the development of such prefabricated panels. It also presents the flexural behavior of such panels as tested under flexural loads following ASTM guidelines. It was observed that these wall panels are much flexible and do not show brittle failure as observed in traditional brick walls. It was observed that prefabricated walls are about 42% cheaper as compared to conventional brick walls. It was also observed that prefabricated walls are considerably lighter in weight and are environment friendly. It was thus concluded that this type of wall panels are an excellent alternative for partition brick walls.

Keywords: bamboo, prefabricated walls, reinforced structure, sustainable infrastructure

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Authors: Nalluri Lakshmi Ramu, C. Venkat Nihit, Narayana Kumar, Dillep

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Masonry bridges are the iconic heritage transportation infrastructure throughout the world. Continuous increase in traffic loads and speed have kept engineers in dilemma about their structural performance and capacity. Henceforth, research community has an urgent need to propose an effective methodology and validate on real-time bridges. The presented research aims to assess the structural health of an Eighty-year-old masonry railway bridge in India using wireless accelerometer sensors. The bridge consists of 44 spans with length of 24.2 m each and individual pier is 13 m tall laid on well foundation. To calculate the dynamic characteristic properties of the bridge, ambient vibrations were recorded from the moving traffic at various speeds and the same are compared with the developed three-dimensional numerical model using finite element-based software. The conclusions about the weaker or deteriorated piers are drawn from the comparison of frequencies obtained from the experimental tests conducted on alternative spans. Masonry is a heterogeneous anisotropic material made up of incoherent materials (such as bricks, stones, and blocks). It is most likely the earliest largely used construction material. Masonry bridges, which were typically constructed of brick and stone, are still a key feature of the world's highway and railway networks. There are 1,47,523 railway bridges across India and about 15% of these bridges are built by masonry, which are around 80 to 100 year old. The cultural significance of masonry bridges cannot be overstated. These bridges are considered to be complicated due to the presence of arches, spandrel walls, piers, foundations, and soils. Due to traffic loads and vibrations, wind, rain, frost attack, high/low temperature cycles, moisture, earthquakes, river overflows, floods, scour, and soil under their foundations may cause material deterioration, opening of joints and ring separation in arch barrels, cracks in piers, loss of brick-stones and mortar joints, distortion of the arch profile. Few NDT tests like Flat jack Tests are being employed to access the homogeneity, durability of masonry structure, however there are many drawbacks because of the test. A modern approach of structural health assessment of masonry structures by vibration analysis, frequencies and stiffness properties is being explored in this paper.

Keywords: masonry bridges, condition assessment, wireless sensors, numerical analysis modal frequencies

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Authors: Sara A. Ben Lashihar

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The heritage building information modelling (HBIM) of the historical masonry buildings has expanded lately to meet the urgent needs for conservation and structural analysis. The masonry structures are unique features for ancient building architectures worldwide that have special cultural, spiritual, and historical significance. However, there is a research gap regarding the reliability of the HBIM modeling process of these structures. The HBIM modeling process of the masonry structures faces significant challenges due to the inherent complexity and uniqueness of their structural systems. Most of these processes are based on tracing the point clouds and rarely follow documents, archival records, or direct observation. The results of these techniques are highly abstracted models where the accuracy does not exceed LOD 200. The masonry assemblages, especially curved elements such as arches, vaults, and domes, are generally modeled with standard BIM components or in-place models, and the brick textures are graphically input. Hence, future investigation is necessary to establish a methodology to generate automatically parametric masonry components. These components are developed algorithmically according to mathematical and geometric accuracy and the validity of the survey data. The main aim of this paper is to provide a comprehensive review of the state of the art of the existing researches and papers that have been conducted on the HBIM modeling of the masonry structural elements and the latest approaches to achieve parametric models that have both the visual fidelity and high geometric accuracy. The paper reviewed more than 800 articles, proceedings papers, and book chapters focused on "HBIM and Masonry" keywords from 2017 to 2021. The studies were downloaded from well-known, trusted bibliographic databases such as Web of Science, Scopus, Dimensions, and Lens. As a starting point, a scientometric analysis was carried out using VOSViewer software. This software extracts the main keywords in these studies to retrieve the relevant works. It also calculates the strength of the relationships between these keywords. Subsequently, an in-depth qualitative review followed the studies with the highest frequency of occurrence and the strongest links with the topic, according to the VOSViewer's results. The qualitative review focused on the latest approaches and the future suggestions proposed in these researches. The findings of this paper can serve as a valuable reference for researchers, and BIM specialists, to make more accurate and reliable HBIM models for historic masonry buildings.

Keywords: HBIM, masonry, structure, modeling, automatic, approach, parametric

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Authors: Gulam Anwer Khan, A. Gautam

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Background: The arch of aorta is a large artery that arches over the root of the left lung and connects the ascending aorta and descending aorta. It is situated in the superior mediastinum behind the manubrium sterni. It gives off three major branches i.e. brachiocephalic trunk, left common carotid artery and left subclavian artery arising from the superior surface of arch of aorta from right to left. Material and Methods: This was a descriptive study. It was carried out in 44 cadavers, obtained during dissections for undergraduates of Department of Anatomy, Chitwan Medical College, Bharatpur, Chitwan, between March 2015 to October 2016. Cadavers of both sexes were included in the present study. The arch of aorta was dissected and exposed according to the methods described by Romanes in Cunningham’s manual of practical anatomy. Results: Out of 44 dissected cadavers, 35 (79.54%) were male and 9 (20.46%) were female cadavers. The normal branching pattern of the arch of aorta was encountered in 28 (63.64%) cadavers and the remaining 16 (36.36%) cadavers showed variations in the branching pattern of arch of aorta. Two different types of variations on the branching pattern of arch of aorta were noted in the present study, in which 12 (27.27%) cadavers had common trunk of the Arch of Aorta. In 3 (5.00%) male cadavers, we found the origin of the Thyroid ima artery. This variation was noted in 1(1.66%) female cadaver. Conclusion: The present study carried out on adult human cadavers’ revealed wide variations in the branching pattern of the arch of ao rta. These variations are of clinical significance and also very useful for the anatomists, radiologists, anesthesiologists, surgeons for practice during angiography, instrumentation, supra-aortic thoracic, head and neck surgery.

Keywords: arch of aorta, brachiocephalic trunk, left common carotid artery, left subclavian artery, Thyroidea ima artery

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Authors: Maryam Kakavand, Samira Entezari, Sara Khoshjamalfekri, Raghad Mimar

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The objective of this study is 1) to compare elite female and beginner taekwondo players in terms of plantar pressure distribution, vertical ground reaction force, contact area, mean pressure, and right and left longitudinal arches, and 2) to compare preferred and non-preferred limbs among elite players. To the best of authors’ knowledge, as of yet, there is no information available about the plantar pressure distribution and arch index among taekwondo players. Material and Methods: An analytical-comparative research method is applied. Therefore seven elite athletes and eight novice athletes were selected. The emed-C50 platform was used to assess plantar pressure distribution, vertical ground reaction force, contact area, mean pressure of different areas, and planter longitudinal arch in a second step protocol. Independent t-test and dependent t-test were used at a level of 0.05 to compare the elites and beginners' right and left feet, and preferred and non-preferred limbs among elite athletes, respectively. Results: In comparing the right and left limbs of elite and beginner groups, findings indicate that there is only a significant difference in the mean pressure of the first metatarsal of the right foot. Findings also showed a significant difference in the contact area of the toes 3, 4, 5 regions between elites’ preferred and non-preferred limbs. However, no significant difference was found between the two groups’ right and left limbs and elites’ preferred and non-preferred limbs in terms of pressure distribution, vertical ground reaction force, and arch index. Conclusion: It seems that taekwondo exercises have affected pressure distribution patterns among advanced players causing some differences in their planter pressure distribution pattern when compared to that of beginners. Therefore, taekwondo exercises may be a factor contributing to asymmetry performance in preferred and non-preferred limbs.

Keywords: planter pressure, arch index, taekwondo, elite

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Authors: V. M. Levshakov, N. A. Steshenkova, N. A. Nosyrev

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Application of hulls processing technologies, based on high-concentrated energy sources (laser and plasma technologies), allow improve shipbuilding production. It is typical for high-speed vessels construction using steel and aluminum alloys with high precision hulls required. Report describes high-performance technologies for plasma welding (using direct current of reversed polarity), laser, and hybrid laser-arc welding of hulls structures developed by JSC “SSTC”.

Keywords: flat sections, hybrid laser-arc welding, plasma welding, plasmatron

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Authors: Kyung-Hoon Jang, Jae-Hyo Park, Kwang-Yeop Jang, Dongjin Kim

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The Tesla coil is an electrical resonant transformer circuit designed by inventor Nikola Tesla in 1891. It is used to produce high voltage, low current and high frequency alternating current electricity. Tesla experimented with a number of different configurations consisting of two or sometimes three coupled resonant electric circuits. This paper focuses on development and high voltage education to apply a Tesla coil to cuisine for high quality flavor and taste conditioning as well as high voltage education under 50 kV corona discharge. The result revealed that the velocity of roasted black belly pork by Tesla coil is faster than that of conventional methods such as hot grill and steel plate etc. depending on applied voltage level and applied voltage time. Besides, carbohydrate and crude protein increased, whereas natrium and saccharides significantly decreased after lightning surge by Tesla coil. This idea will be useful in high voltage education and high voltage application.

Keywords: corona discharge, Tesla coil, high voltage application, high voltage education

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Authors: Turki Mohammed Al Mohaid

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High arousal may lead to inhibited athletic performance, or high positive arousal may enhance performance is controversial. To evaluate and review this issue, 31 athletes (all male) were induced into high pre-determined goal arousal and high arousal without pre-determined goal motivational states and tested on a standard grip strength task. Paced breathing was used to change psychological and physiological arousal. It was noted that significant increases in grip strength performance occurred when arousal was high and experienced as delighted, happy, and pleasant excitement in those with no pre-determined goal motivational states. Blood pressure, heart rate, and other indicators of physiological activity were not found to mediate between psychological arousal and performance. In a situation where athletic performance necessitates maximal motor strength over a short period, performance benefits of high arousal may be enhanced by designing a specific motivational state.

Keywords: high arousal, athletic, performance, physiological

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Authors: Shaoxi Wang, Pouya Rezai

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High aspect ratio is the necessary parts of complex microstructures. Some methods available to achieve high aspect ratio requires expensive materials or complex process; others is difficult to research simple high aspect ratio structures. The paper presents a simple and cheap two-step Polydimethylsioxane (PDMS) transferring process to get high aspect ratio single pillars, which only requires covering the PDMS mold with Brij@52 surface solution. The experimental results demonstrate the method efficiency and effective.

Keywords: high aspect ratio, microstructure, PDMS, Brij

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Authors: B. Akturk, N. Yuzer, N. Kabay

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High temperature is one of the most detrimental effects that cause important changes in concrete’s mechanical, physical, and thermo-physical properties. As a result of these changes, especially high strength concrete (HSC), may exhibit damages such as cracks and spallings. To overcome this problem, incorporating polymer fibers such as polypropylene (PP) in concrete is a very well-known method. In this study, using RRH as a sustainable material instead of PP fiber in HSC to prevent spallings and improve physical and thermo-physical properties were investigated. Therefore, seven HSC mixtures with 0.25 water to binder ratio were prepared, incorporating silica fume and blast furnace slag. PP and RRH were used at 0.2-0.5% and 0.5-3% by weight of cement, respectively. All specimens were subjected to high temperatures (20 (control), 300, 600 and 900˚C) with a heating rate of 2.5˚C/min and after cooling, residual physical and thermo-physical properties were determined.

Keywords: high temperature, high strength concrete, polypropylene fiber, raw rice husk, thermo-physical properties

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Authors: Vaishnavi Patil, K. M. Kurundkar

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Electrical Drives play a vital role in industry development and applications. Drives have an inevitable part in the needs of various fields such as industry, commercial, and domestic applications. The development of material technology, Power Electronics devices, and accompanying applications led to the focus of industry and researchers on high-speed electrical drives. Numerous articles charted the applications of electrical machines and various converters for high-speed applications. The choice depends on the application under study. This paper goals to highlight high-speed applications, main challenges, and some applications of electrical drives in the field.

Keywords: high-speed, electrical machines, drives, applications

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Authors: Noha Al Majid, Said Mazer, Moulhime El Bekkali, Catherine Algani, Mahmoud Mehdi

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A low noise figure (NF) and high linearity V-band Low Noise Amplifier (LNA) is reported in this article. The LNA compromises a three-stage cascode configuration. This LNA will be used as a part of a WPAN (Wireless Personal Area Network) receiver in the millimeter-wave band at 60 GHz. It is designed according to the MMIC technology (Monolithic Microwave Integrated Circuit) in PH 15 process from UMS foundry and uses a 0.15 μm GaAs PHEMT (Pseudomorphic High Electron Mobility Transistor). The particularity of this LNA compared to other LNAs in literature is its very low noise figure which is equal to 1 dB and its high linearity (IIP3 is about 22 dB). The LNA consumes 0.24 Watts, achieving a high gain which is about 23 dB, an input return loss better than -10 dB and an output return loss better than -8 dB.

Keywords: low noise amplifier, V-band, MMIC technology, LNA, amplifier, cascode, pseudomorphic high electron mobility transistor (PHEMT), high linearity

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Authors: Gilbert Makanda, Roelf Sypkens

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In this study we investigated the relevance of high school mathematics in university education. The paper particularly focused on whether the concepts taught in high school are enough for engineering courses at diploma level. The study identified particular concepts that are required in engineering courses whether they were adequately covered in high school. A questionnaire was used to investigate whether relevant topics were covered in high school. The respondents were 228 first year students at the Central University of Technology in the Faculty of Engineering and Information Technology. The study indicates that there are some topics such as integration, complex numbers and matrices that are not done at high schools and are required in engineering courses at university. It is further observed that some students did not cover the topics that are in the current syllabus. Female students enter the university less prepared than their male counterparts. More than 30% of the respondents in this study felt that high school mathematics was not useful for them to be able to do engineering courses.

Keywords: high school mathematics, university education, SPSS package, students' perceptions

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Authors: S. Slimani, B. Djellouli

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Novel materials and innovative device structures has become necessary for the future of CMOS. High mobility materials like Ge is a very promising material due to its high mobility and is being considered to replace Si in the channel to achieve higher drive currents and switching speeds .Various approaches to circumvent the scaling limits to benchmark the performance of nanoscale MOSFETS with different channel materials, the optimized structure is simulated within nextnano in order to highlight the quantum effects on DG MOSFETs when Si is replaced by Ge and SiO2 is replaced by ZrO2 and HfO2as the gate dielectric. The results have shown that Ge MOSFET have the highest mobility and high permittivity oxides serve to maintain high drive current. The simulations show significant improvements compared with DGMOSFET using SiO2 gate dielectric and Si channel.

Keywords: high mobility, high-k, quantum effects, SOI-DGMOSFET

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Authors: Branci Sarra, Branci Saadia

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Because of the multiplied data growth, many computer science tools have been developed to process and analyze these Big Data. High-performance computing architectures have been designed to meet the treatment needs of Big Data (view transaction processing standpoint, strategic, and tactical analytics). The purpose of this article is to provide a historical and global perspective on the recent trend of high-performance computing architectures especially what has a relation with Analytics and Data Mining.

Keywords: high performance computing, HPC, big data, data analysis

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Authors: Suat Erel, Gozde Gur

Abstract:

Background: Recently a supramalleolar type of dynamic ankle foot orthosis (DAFO) has been increasingly used to support all of the dynamic arches of the foot and redistribute the pressure under the plantar surface of the foot to reduce the muscle tone. DAFO helps to maintain balance and postural control by providing stability and proprioceptive feedback in children with disease like Cerebral Palsy, Muscular Dystrophies, Down syndrome, and congenital hypotonia. Aim: The aim of this study was to investigate the role of Dynamic ankle foot orthosis (DAFO) on temporo-spatial parameters of gait and balance in three children with hereditary spastic paraparesis (HSP). Material Method: 13, 14, and 8 years old three children with HSP were included in the study. To provide correction on weight bearing and to improve gait, DAFO was made. Lower extremity spasticity (including gastocnemius, hamstrings and hip adductor muscles) using modified Ashworth Scale (MAS) (0-5), The temporo-spatial gait parameters (walking speed, cadence, base of support, step length) and Timed Up & Go test (TUG) were evaluated. All of the assessments about gait were compared with (with DAFO and shoes) and without DAFO (with shoes only) situations. Also after six months follow up period, assessments were repeated by the same physical therapist. Results: MAS scores for lower extremity were between “2-3” for the first child, “0-2” for the second child and “1-2” for the third child. TUG scores (sec) decreased from 20.2 to 18 for case one, from 9.4 to 9 for case two and from 12,4 to 12 for case three in the condition with shoes only and also from 15,2 to 14 for case one, from 7,2 to 7,1 for case two and from 10 to 7,3 for case three in the condition with DAFO and shoes. Gait speed (m/sec) while wearing shoes only was similar but while wearing DAFO and shoes increased from 0,4 to 0,5 for case one, from 1,5 to 1,6 for case two and from 1,0 to 1,2 for case three. Base of support scores (cm) wearing shoes only decreased from 18,5 to 14 for case one, from 13 to 12 for case three and were similar as 11 for case two. While wearing DAFO and shoes, base of support decreased from 10 to 9 for case one, from 11,5 to 10 for case three and was similar as 8 for case two. Conclusion: The use of a DAFO in a patient with HSP normalized the temporo-spatial gait parameters and improved balance. Walking speed is a gold standard for evaluating gait quality. With the use of DAFO, walking speed increased in this three children with HSP. With DAFO, better TUG scores shows that functional ambulation improved. Reduction in base of support and more symmetrical step lengths with DAFO indicated better balance. These encouraging results warrant further study on wider series.

Keywords: dynamic ankle foot orthosis, gait, hereditary spastic paraparesis, balance in patient

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Authors: Endah Mastuti, Prihastuti Sudaryono

Abstract:

The rapid development of Internet usage and technology influences the academic behavior of students in high schools. One of the consequences is the emergence of academic procrastination behavior. Academic procrastination behavior is students’ procrastinate behavior in completing assignments. This study aimed to see whether there are differences in the duration of using the internet with academic procrastinate behavior among high school students in Surabaya. The number of research subject is 498 high school students. Instruments of the research are academic procrastination scale and duration of the internet usage questionnaire. The results from One Way Anova shows F value 0.241 with a significance level of 0.868 This demonstrates that there is no difference between the duration of the use of the Internet with academic procrastination behavior in high school students.

Keywords: academic procrastination, duration of internet usage, students, senior high school

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Authors: Raweyah Al-Sedairawi

Abstract:

While high-rise housing detained massive negative connotations on several societies and well-being, this typology did deliver housing demand efficiently. Despite its adverse reference due to declining precedents, high-rise housing is still in global demand. Yet the suitability of this typology is still questioned. In this research, the suitability of high-rise housing as a socio-culturally sustainable solution to meet housing demands will be examined. By questioning what is the potential of high-rise housing as a socio-culturally sustainable solution for housing demands, the research will examine some high-rise housing practices. Through reviewing the literature on the origins of high-rise housing, how and why they were developed, some unsuccessful cases, and some successful cases, with the identification of factors for successful high-rise living. Thus, the research groundings will materialize from existing patterns of housing demands. Whilst most of the literature covers the housing market from an economic, real estate, and political perspective, there is less amount that discloses occupants’ reactions towards this typology and its appropriateness for the reason that income controls individuals’ choices. To bridge the gap, the prospect of implementing the study would be effective. This will be applied through a mixture of a qualitative and a quantitative methodology by conducting questionnaires and focus groups on existing cases of high-net-worth residential towers.

Keywords: architecture, behaviors, high-rise, socio-cultural, sustainability

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Authors: Yazid Abdullahi Abubakar, Jay Mitra

Abstract:

This paper is concerned with entrepreneurial high-impact firms, which are firms that generate ‘both’ disproportionate levels of employment and sales growth, and have high levels of innovative activity. It investigates differences in factors influencing high-impact growth between indigenous and foreign firms. The study is based on an analysis of data from United Kingdom (UK) Innovation Scoreboard on 865 firms, which were divided into high-impact firms (those achieving positive growth in both sales and employment) and low-impact firms (negative or no growth in sales or employment); in order to identifying the critical differences in regional, sectorial and size related factors that facilitate knowledge spillovers and high-impact growth between indigenous and foreign firms. The findings suggest that: 1) Firms’ access to regional knowledge spillovers (from businesses and higher education institutions) is more significantly associated with high-impact growth of UK firms in comparison to foreign firms, 2) Because high-tech sectors have greater use of knowledge spillovers (compared to low-tech sectors), high-tech sectors are more associated with high-impact growth, but the relationship is stronger for UK firms compared to foreign firms, 3) Because small firms have greater need for knowledge spillovers (relative to large firms), there is a negative relationship between firm size and high-impact growth, but the negative relationship is greater for UK firms in comparison to foreign firms.

Keywords: entrepreneurship, high-growth, indigenous firms, foreign firms, small firms, large firms

Procedia PDF Downloads 428