Search results for: flat slab

Authors: Jovana Jankovic Pantic, Dragoslav Rakic, Tina Djuric, Irena Basaric Ikodinovic, Snezana Bogdanovic

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Regardless of the numerous activities undertaken to reduce municipal solid waste, its annual volumes continue to grow. In Serbia, the most common and the only one form of waste disposal is at municipal landfills with daily compaction and soil covering. Municipal waste compacting is one of the basic components of the disposal process. Well compacted waste takes up less volume and allows much safer storage. In order to better predict the behavior of municipal waste at landfills, it is necessary to define compaction parameters: the maximum dry unit weight and optimal moisture content. In current geotechnical practice, the most common method of determination compaction parameters is by the standard method (Proctor compaction test) used in soil mechanics, with an eventual reduction of compaction energy. Although this methodology is accepted in newer geotechnical scientific discipline "waste mechanics", different treatments of municipal waste at the landfill itself (including pretreatment), indicate the need to change this classical approach. The main reason for that is the simulation of the operation of compactors (hedgehogs) at the landfill. Therefore, during the research, various innovative solutions are introduced, such as changing the classic flat Proctor hammer, by adding spikes, whose function is, in addition to compaction, destruction and shredding of municipal waste. The paper presents the behavior of municipal waste for four synthetic waste samples with different waste compositions (Plandište landfill). The samples were tested in standard Proctor apparatus at the same compaction energy, but with two different hammers: standard flat hammer and hammer with spikes.

Keywords: compaction, hammer with spikes, landfill, municipal solid waste, proctor compaction test

Procedia PDF Downloads 196

Authors: Nurdiani Zamhari, Abang Annuar Ehsan

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The 3 dB directional coupler is designed by using silicon-on-insulator (SOI) large cross-section and simulate by Beam Propagation Method at the communication wavelength of 1.55 µm and 1.48 µm. The geometry is shaped with rib height (H) of 6 µm and varied in step factor (r) which is 0.5, 0.6, 0.7 and 0.8. The wave guide spacing is also fixed to 5 µm and the slab width is symmetrical. In general, the 3 dB coupling lengths for four different cross-sections are several millimetre long. The 1.48 of wavelength give the longer coupling length if compare to 1.55 at the same step factor (r). Besides, the low loss propagation is achieved with less than 2 % of propagation loss.

Keywords: 3 dB directional couplers, silicon-on-insulator, symmetrical rib waveguide, OptiBPM 9

Procedia PDF Downloads 486

Authors: Mohamed I. Alzarah

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Passive dew harvesting and rainwater collection requires a very small financial investment meanwhile they can exploit a free and clean source of water in rural or remote areas. Dew condensation on greenhouse dryer cladding and assorted other surfaces was frequently noticed. Accordingly, this study was performed in order to measure the quantity of condensation in the arid regions. Dew was measured by using three different kinds of collectors which were glass of flat plate solar collector, tempered glass of photovoltaic (PV) and double sloped (25°) acrylic plexiglas of greenhouse dryer. The total amount of dew collection for three different types of collectors was measured during December 2013 to March 2014 in Alahsa, Saudi Arabia. Meteorological data were collected for one year. The condensate dew drops were collected naturally (before scraping) and by scraping once and twice. Dew began to condense most likely between 12:00 am and 6:30 am and its intensity reached the peak at about 45 min before sunrise. The cumulative dew yield on double-sloped test roof was varying with wind speed and direction. Results indicated that, wiping twice gave more dew yield compared to wiping once or collection by gravity. Dew and rain pH were neutral (close to 7) and the total mineralization was considerable. The ions concentration agrees with the World Health Organization recommendations for potable water. Using existing drying system for dew and rain harvesting cold provide a potable water source for arid region.

Keywords: PV module, flat plate solar collector, greenhouse, drying system, dew collection, water vapor, rainwater harvesting

Procedia PDF Downloads 303

Authors: Karthikeyan Kalirajan, Ashok Joshi

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An optimization problem is to setup to maximize the terminal kinetic energy of a maneuverable reentry vehicle (MaRV). The target location, the impact angle is given as constraints. The MaRV uses an explicit guidance law called Vector guidance. This law has two gains which are taken as decision variables. The problem is to find the optimal value of these gains which will result in minimum miss distance and impact angle error. Using a simple 3DOF non-rotating flat earth model and Lockheed martin HP-MARV as the reentry vehicle, the nature of solutions of the optimization problem is studied. This is achieved by carrying out a parametric study for a range of closed loop gain values and the corresponding impact angle error and the miss distance values are generated. The results show that there are well defined lower and upper bounds on the gains that result in near optimal terminal guidance solution. It is found from this study, that there exist common permissible regions (values of gains) where all constraints are met. Moreover, the permissible region lies between flat regions and hence the optimization algorithm has to be chosen carefully. It is also found that, only one of the gain values is independent and that the other dependent gain value is related through a simple straight-line expression. Moreover, to reduce the computational burden of finding the optimal value of two gains, a guidance law called Diveline guidance is discussed, which uses single gain. The derivation of the Diveline guidance law from Vector guidance law is discussed in this paper.

Keywords: Marv guidance, reentry trajectory, trajectory optimization, guidance gain selection

Procedia PDF Downloads 397

Authors: Uday S. Goel, G. Senthil Kumar, Biswajit Ghosh, V. V. Mahashabde, Dhirendra Kumar, H. Manjunath, Ritesh Kumar, Mahesh Bhagwat, Subodh Pandey

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Tata Steel Bhushan Steel Ltd.(TSBSL)’s Hot Mill at Angul , Orissa , India, was facing shape issues in Hot Rolled (HR) coils. This was resulting in a defect called as ‘Ridge’, which was appearing in subsequent cold rolling operations at various cold mills (CRM) and external customers. A collaborative project was undertaken to resolve this issue. One of the reasons identified was the strange drop in thermal crown after rolling of 20-25 coils in the finishing mill (FM ) schedule. On the shop floor, it was observed that work roll temperatures in the FM after rolling were very high and non uniform across the work roll barrel. Jammed work roll cooling nozzles, insufficient roll bite lubrication and inadequate roll cooling water quality were found to be the main reasons. Regular checking was initiated to check roll cooling nozzles health, and quick replacement done if found jammed was implemented. Improvements on roll lubrication, especially flow rates, was done. Usage of anti-peeling headers and inter stand descaling was enhanced. A subsequent project was also taken up for improving the quality of roll cooling water. Encouraging results were obtained from the project with a reduction in rejection due to ridge at CRM’s by almost 95% of the pre project start levels. Poor profile occurrence of HR coils at HSM was also reduced from a high of 32% in May’19 to <1% since Apr’20.

Keywords: hot rolling flat, shape, ridge, work roll, roll cooling nozzle, lubrication

Procedia PDF Downloads 54

Authors: Mohsen Abdelrazek Khorshid Ali Selim

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Disadvantages and errors of current concrete reinforcement methodsL: Current concrete reinforcement methods are adopted in most parts of the world in their various doctrines and names. They adopt the so-called concrete slab system, where these slabs are semi-independent and isolated from each other and from the surrounding environment of concrete columns or beams, so that the reinforcing steel does not cross from one slab to another or from one slab to adjacent columns. It or the beams surrounding it and vice versa are only a few centimeters and no more. The same applies exactly to the concrete columns that support the building, where the reinforcing steel does not extend from the slabs or beams to the inside of the columns or vice versa except for a few centimeters and no more, just as the reinforcing steel does not extend from inside the column at the top. The ceiling is only a few centimetres, and the same thing is literally repeated in the concrete beams that connect the columns and separate the slabs, where the reinforcing steel does not cross from one beam to another or from one beam to the slabs or columns adjacent to it and vice versa, except for a few centimeters, which makes the basic building elements of columns, slabs and beams They all work in isolation from each other and from the environment surrounding them from all sides. This traditional method of reinforcement may be valid and lasting in geographical areas that are not exposed to earthquakes and earthquakes, where all the loads and tensile forces in the building are constantly directed vertically downward due to gravity and are borne directly by the vertical reinforcement of the building. However, in the case of earthquakes and earthquakes, the loads and tensile forces in the building shift from the vertical direction to the horizontal direction at an angle of inclination that depends on the strength of the earthquake, and most of them are borne by the horizontal reinforcement extending between the basic elements of the building, such as columns, slabs and beams, and since the crossing of the reinforcement between each of the columns, slabs and beams between them And each other, and vice versa, does not exceed several centimeters. In any case, the tensile strength, cohesion and bonding between the various parts of the building are very weak, which causes the buildings to disintegrate and collapse in the horrific manner that we saw in the earthquake in Turkey and Syria in February 2023, which caused the collapse of tens of thousands of buildings in A few seconds later, it left more than 50,000 dead, hundreds of thousands injured, and millions displaced. Description of the new earthquake-resistant model: The idea of the new model in the reinforcement of concrete buildings and constructions is based on the theory that we have formulated as follows: [The tensile strength, cohesion and bonding between the basic parts of the concrete building (columns, beams and slabs) increases as the lengths of the reinforcing steel bars increase and they extend and branch and the different parts of the building share them with each other.] . In other words, the strength, solidity, and cohesion of concrete buildings increase and they become resistant to earthquakes as the lengths of the reinforcing steel bars increase, extend, branch, and share with the various parts of the building, such as columns, beams, and slabs. That is, the reinforcing skewers of the columns must extend in their lengths without cutting to cross from one floor to another until their end. Likewise, the reinforcing skewers of the beams must extend in their lengths without cutting to cross from one beam to another. The ends of these skewers must rest at the bottom of the columns adjacent to the beams. The same thing applies to the reinforcing skewers of the slabs where they must These skewers should be extended in their lengths without cutting to cross from one tile to another, and the ends of these skewers should rest either under the adjacent columns or inside the beams adjacent to the slabs as follows: First, reinforce the columns: The columns have the lion's share of the reinforcing steel in this model in terms of type and quantity, as the columns contain two types of reinforcing bars. The first type is large-diameter bars that emerge from the base of the building, which are the nerves of the column. These bars must extend over their normal length of 12 meters or more and extend to a height of three floors, if desired. In raising other floors, bars with the same diameter and the same length are added to the top after the second floor. The second type is bars with a smaller diameter, and they are the same ones that are used to reinforce beams and slabs, so that the bars that reinforce the beams and slabs facing each column are bent down inside this column and along the entire length of the column. This requires an order. Most engineers do not prefer it, which is to pour the entire columns and pour the roof at once, but we prefer this method because it enables us to extend the reinforcing bars of both the beams and slabs to the bottom of the columns so that the entire building becomes one concrete block that is cohesive and resistant to earthquakes. Secondly, arming the cameras: The beams' reinforcing skewers must also extend to a full length of 12 meters or more without cutting. The ends of the skewers are bent and dropped inside the column at the beginning of the beam to its bottom. Then the skewers are extended inside the beam so that their other end falls under the facing column at the end of the beam. The skewers may cross over the head of a column. Another passes through another adjacent beam and rests at the bottom of a third column, according to the lengths of each of the skewers and beams. Third, reinforcement of slabs: The slab reinforcing skewers must also extend their entire length, 12 meters or more, without cutting, distinguishing between two cases. The first case is the skewers opposite the columns, and their ends are dropped inside one of the columns. Then the skewers cross inside the adjacent slab and their other end falls below the opposite column. The skewers may cross over The head of the adjacent column passes through another adjacent slab and rests at the bottom of a third column, according to the dimensions of the slabs and the lengths of the skewers. The second case is the skewers opposite the beams, and their ends must be bent in the form of a square or rectangle according to the dimensions of the beam’s width and height, and this square or rectangle is dropped inside the beam at the beginning of the slab, and it serves as The skewers are for the beams, then the skewers are extended along the length of the slab, and at the end of the slab, the skewers are bent down to the bottom of the adjacent beam in the shape of the letter U, after which the skewers are extended inside the adjacent slab, and this is repeated in the same way inside the other adjacent beams until the end of the skewer, then it is bent downward in the form of a square or rectangle inside the beam, as happened. In its beginning.

Keywords: earthquake resistant buildings, earthquake resistant concrete constructions, new technology for reinforcement of concrete buildings, new technology in concrete reinforcement

Procedia PDF Downloads 32

Authors: Matjaz Prek

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Impact of three different combinations of cooling and ventilation systems on the indoor environmental quality (IEQ) has been studied. Comparison of chilled ceiling cooling in combination with displacement ventilation, cooling with fan coil unit and cooling with flat wall displacement outlets was performed. All three combinations were evaluated from the standpoint of whole-body and local thermal comfort criteria as well as from the standpoint of ventilation effectiveness. The comparison was made on the basis of numerical simulation with DesignBuilder and Fluent. Numerical simulations were carried out in two steps. Firstly the DesignBuilder software environment was used to model the buildings thermal performance and evaluation of the interaction between the environment and the building. Heat gains of the building and of the individual space, as well as the heat loss on the boundary surfaces in the room, were calculated. In the second step Fluent software environment was used to simulate the response of the indoor environment, evaluating the interaction between building and human, using the simulation results obtained in the first step. Among the systems presented, the ceiling cooling system in combination with displacement ventilation was found to be the most suitable as it offers a high level of thermal comfort with adequate ventilation efficiency. Fan coil cooling has proved inadequate from the standpoint of thermal comfort whereas flat wall displacement outlets were inadequate from the standpoint of ventilation effectiveness. The study showed the need in evaluating indoor environment not solely from the energy use point of view, but from the point of view of indoor environmental quality as well.

Keywords: cooling, ventilation, thermal comfort, ventilation effectiveness, indoor environmental quality, IEQ, computational fluid dynamics

Procedia PDF Downloads 157

Authors: Aleksandr I. Korobov, Natalia V. Shirgina, Aleksey I. Kokshaiskiy

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The transformation of two types of acoustic waves can occur on a flat interface between two solids at oblique incidence of longitudinal and shear bulk acoustic waves (BAW). This paper presents the results of experimental studies of the properties of reflection and propagation of longitudinal wave and generation of second and third longitudinal and shear harmonics of BAW at oblique incidence of longitudinal BAW on a flat rough boundary between two solids. The experimental sample was a rectangular isosceles pyramid made of D16 aluminum alloy with the plane parallel bases cylinder made of D16 aluminum alloy pressed to the base. The piezoelectric lithium niobate transducer with a resonance frequency of 5 MHz was secured to one face of the pyramid to generate a longitudinal wave. Longitudinal waves emitted by this transducer felt at an angle of 45° to the interface between two solids and reflected at the same angle. On the opposite face of the pyramid, and on the flat side of the cylinder was attached longitudinal transducer with resonance frequency of 10 MHz or the shear transducer with resonance frequency of 15 MHz. These transducers also effectively received signal at a frequency of 5 MHz. In the spectrum of the transmitted and reflected BAW was observed shear and longitudinal waves at a frequency of 5 MHz, as well as longitudinal harmonic at a frequency harmonic of 10 MHz and a shear harmonic at frequency of 15 MHz. The effect of reversing changing of external pressure applied to the rough interface between two solids on the value of the first and higher harmonics of the BAW at oblique incidence on the interface of the longitudinal BAW was experimentally investigated. In the spectrum of the reflected signal from the interface, there was a decrease of amplitudes of the first harmonics of the signal, and non-monotonic dependence of the second and third harmonics of shear wave with an increase of the static pressure applied to the interface. In the spectrum of the transmitted signal growth of the first longitudinal and shear harmonic amplitude and non-monotonic dependence - first increase and then decrease in the amplitude of the second and third longitudinal shear harmonic with increasing external static pressure was observed. These dependencies were hysteresis at reversing changing of external pressure. When pressure applied to the border increased, acoustic contact between the surfaces improves. This increases the energy of the transmitted elastic wave and decreases the energy of the reflected wave. The second longitudinal acoustic harmonics generation was associated with the Hertz nonlinearity on the interface of two pressed rough surfaces, the generation of the third harmonic was caused by shear hysteresis nonlinearity due to dry friction on a rough interface. This study was supported by the Russian Science Foundation (project №14-22-00042).

Keywords: generation of acoustic harmonics, hysteresis nonlinearity, Hertz nonlinearity, transformation of acoustic waves

Procedia PDF Downloads 349

Authors: Icaro V. Soares, Guilherme L. F. Brandao, Ursula D. C. Resende, Glaucio L. Siqueira

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Electrical energy can be wirelessly transmitted through resonant coupled coils that operate in the near-field region. Once in this region, the field has evanescent character, the efficiency of Resonant Wireless Power Transfer (RWPT) systems decreases proportionally with the inverse cube of distance between the transmitter and receiver coils. The commercially available RWPT systems are restricted to short and mid-range applications in which the distance between coils is lesser or equal to the coil size. An alternative to overcome this limitation is applying metamaterial structures to enhance the coupling between coils, thus reducing the field decay along the distance between them. Metamaterials can be conceived as composite materials with periodic or non-periodic structure whose unconventional electromagnetic behaviour is due to its unit cell disposition and chemical composition. This new kind of material has been used in frequency selective surfaces, invisibility cloaks, leaky-wave antennas, among other applications. However, for RWPT it is mainly applied as superlenses which are lenses that can overcome the optical limitation and are made of left-handed media, that is, a medium with negative magnetic permeability and electric permittivity. As RWPT systems usually operate at wavelengths of hundreds of meters, the metamaterial unit cell size is much smaller than the wavelength. In this case, electric and magnetic field are decoupled, therefore the double negative condition for superlenses are not required and the negative magnetic permeability is enough to produce an artificial magnetic medium. In this work, the influence of the magnetic permeability of a metamaterial slab inserted between two loosely coupled coils is studied in order to find the condition that leads to the maximum transmission efficiency. The metamaterial used is formed by a subwavelength unit cell that consist of a capacitor-loaded split ring with an inner spiral that is designed and optimized using the software Computer Simulation Technology. The unit cell permeability is experimentally characterized by the ratio of the transmission parameters between coils measured with and without the presence of the metamaterial slab. Early measurements results show that the transmission coefficient at the resonant frequency after the inclusion of the metamaterial is about three times higher than with just the two coils, which confirms the enhancement that this structure brings to RWPT systems.

Keywords: electromagnetic lens, loosely coupled coils, magnetic permeability, metamaterials, resonant wireless power transfer, subwavelength unit cells

Procedia PDF Downloads 123

Authors: Kang Lin Peng

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Space tourism emerged in 2001 and became famous in 2021, following the development of space technology. The space market is twisted because of the excess demand. Space tourism is currently rare and extremely expensive, with biased luxury product pricing, which is the seller’s market that consumers can not bargain with. Spaceship companies such as Virgin Galactic, Blue Origin, and Space X have been charged space tourism prices from 200 thousand to 55 million depending on various heights in space. There should be a reasonable price based on a fair basis. This study aims to derive a spacetime pricing model, which is different from the general pricing model on the earth’s surface. We apply general relativity theory to deduct the mathematical formula for the space tourism pricing model, which covers the traditional time-independent model. In the future, the price of space travel will be different from current flight travel when space travel is measured in lightyear units. The pricing of general commodities mainly considers the general equilibrium of supply and demand. The pricing model considers risks and returns with the dependent time variable as acceptable when commodities are on the earth’s surface, called flat spacetime. Current economic theories based on the independent time scale in the flat spacetime do not consider the curvature of spacetime. Current flight services flying the height of 6, 12, and 19 kilometers are charging with a pricing model that measures time coordinate independently. However, the emergence of space tourism is flying heights above 100 to 550 kilometers that have enlarged the spacetime curvature, which means tourists will escape from a zero curvature on the earth’s surface to the large curvature of space. Different spacetime spans should be considered in the pricing model of space travel to echo general relativity theory. Intuitively, this spacetime commodity needs to consider changing the spacetime curvature from the earth to space. We can assume the value of each spacetime curvature unit corresponding to the gradient change of each Ricci or energy-momentum tensor. Then we know how much to spend by integrating the spacetime from the earth to space. The concept is adding a price p component corresponding to the general relativity theory. The space travel pricing model degenerates into a time-independent model, which becomes a model of traditional commodity pricing. The contribution is that the deriving of the space tourism pricing model will be a breakthrough in philosophical and practical issues for space travel. The results of the space tourism pricing model extend the traditional time-independent flat spacetime mode. The pricing model embedded spacetime as the general relativity theory can better reflect the rationality and accuracy of space travel on the universal scale. The universal scale from independent-time scale to spacetime scale will bring a brand-new pricing concept for space traveling commodities. Fair and efficient spacetime economics will also bring to humans’ travel when we can travel in lightyear units in the future.

Keywords: space tourism, spacetime pricing model, general relativity theory, spacetime curvature

Procedia PDF Downloads 87

Authors: Annamária Käferné Rácz, Bence Jáger, Balázs Kövesdi, László Dunai

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Due to the numerous advantages of steel corrugated web girders, its application field is growing for bridges as well as for buildings. The global stability behavior of such girders is significantly larger than those of conventional I-girders with flat web, thus the application of the structural steel material can be significantly reduced. Design codes and specifications do not provide clear and complete rules or recommendations for the determination of the lateral torsional buckling (LTB) resistance of corrugated web girders. Therefore, the authors made a thorough investigation regarding the LTB resistance of the corrugated web girders. Finite element (FE) simulations have been performed to develop new design formulas for the determination of the LTB resistance of trapezoidally corrugated web girders. FE model is developed considering geometrical and material nonlinear analysis using equivalent geometric imperfections (GMNI analysis). The equivalent geometric imperfections involve the initial geometric imperfections and residual stresses coming from rolling, welding and flame cutting. Imperfection sensitivity analysis was performed to determine the necessary magnitudes regarding only the first eigenmodes shape imperfections. By the help of the validated FE model, an extended parametric study is carried out to investigate the LTB resistance for different trapezoidal corrugation profiles. First, the critical moment of a specific girder was calculated by FE model. The critical moments from the FE calculations are compared to the previous analytical calculation proposals. Then, nonlinear analysis was carried out to determine the ultimate resistance. Due to the numerical investigations, new proposals are developed for the determination of the LTB resistance of trapezoidally corrugated web girders through a modification factor on the design method related to the conventional flat web girders.

Keywords: corrugated web, lateral torsional buckling, critical moment, FE modeling

Procedia PDF Downloads 264

Authors: M. Jaenen, M. de Bouw, A. Verdonck, M. Leus

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During the interwar period artificial materials were often preferred, but many Antwerp architects relied on the application of wood for most of the interior finishing works and furnishings. Archival, literature and on site research of interwar suburban townhouses and the Belgian wood and furniture industry gave a new insight to the application of wood in the interwar interior. Many interwar designers favored the decorative values in all treatments of wood because of its warmth, comfort, good-wearing, and therefore, economic qualities. For the creation of a successful modern interior the texture and surface of the wood becomes as important as the color itself. This aesthetics valuation was the result of the modernization of the wood industry. The development of veneer and plywood gave the possibility to create strong, flat, long and plain wooden surfaces which are capable of retaining their shape. Also the modernization of cutting machines resulted in high quality and diversity in texture of veneer. The flat and plain plywood surfaces were modern decorated with all kinds of veneer-sliced options. In addition, wood species from the former Belgian Colony Congo were imported. Limba (Terminalia superba), kambala (Chlorophora excelsa), mubala (Pentaclethra macrophylla) and sapelli (Entandrophragma cylindricum) were used in the interior of many Antwerp interwar suburban town houses. From the thirties onwards Belgian wood firms established modern manufactures in Congo. There the local wood was dried, cut and prepared for exportation to the harbor of Antwerp. The presence of all kinds of strong and decorative Congolese wood products supported its application in the interwar interior design. The Antwerp architects combined them in their designs for doors, floors, stairs, built-in-furniture, wall paneling and movable furniture.

Keywords: Antwerp, congo, furniture, interwar

Procedia PDF Downloads 191

Authors: Mahesh Suresh Kumawat

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Steel concrete composite construction means the concrete slab is connected to the steel beam with the help of shear connectors so that they act as a single unit. In the present work, steel concrete composite with RCC options are considered for comparative study of G+9 story commercial building which is situated in earthquake zone-III and for earthquake loading, the provisions of IS: 1893(Part1)-2002 is considered. A three dimensional modeling and analysis of the structure are carried out with the help of SAP 2000 software. Equivalent Static Method of Analysis and Response spectrum analysis method are used for the analysis of both Composite & R.C.C. structures. The results are compared and it was found that composite structure is more economical.

Keywords: composite beam, column, RCC column, RCC beam, shear connector, SAP 2000 software

Procedia PDF Downloads 412

Authors: Ali H. Daraji, Ye Jianqiao

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The micro electrical devices of the wireless sensor network are continuously developed and become very small and compact with low electric power requirements using limited period life conventional batteries. The low power requirement for these devices, cost of conventional batteries and its replacement have encouraged researcher to find alternative power supply represented by energy harvesting system to provide an electric power supply with infinite period life. In the last few years, the investigation of energy harvesting for structure health monitoring has increased to powering wireless sensor network by converting waste mechanical vibration into electricity using piezoelectric sensors. Optimisation of energy harvesting is an important research topic to ensure a flowing of efficient electric power from structural vibration. The harvesting power is mainly based on the properties of piezoelectric material, dimensions of piezoelectric sensor, its position on a structure and value of an external electric load connected between sensor electrodes. Larger surface area of sensor is not granted larger power harvesting when the sensor area is covered positive and negative mechanical strain at the same time. Thus lead to reduction or cancellation of piezoelectric output power. Optimisation of energy harvesting is achieved by locating these sensors precisely and efficiently on the structure. Limited published work has investigated the energy harvesting for aircraft wing. However, most of the published studies have simplified the aircraft wing structure by a cantilever flat plate or beam. In these studies, the optimisation of energy harvesting was investigated by determination optimal value of an external electric load connected between sensor electrode terminals or by an external electric circuit or by randomly splitting piezoelectric sensor to two segments. However, the aircraft wing structures are complex than beam or flat plate and mostly constructed from flat and curved skins stiffened by stringers and ribs with more complex mechanical strain induced on the wing surfaces. This aircraft wing structure bonded with discrete macro fibre composite sensors was modelled using multiphysics finite element to optimise the energy harvesting by determination of the optimal number of sensors, location and the output resistance load. The optimal number and location of macro fibre sensors were determined based on the maximization of the open and close loop sensor output voltage using frequency response analysis. It was found different optimal distribution, locations and number of sensors bounded on the top and the bottom surfaces of the aircraft wing.

Keywords: energy harvesting, optimisation, sensor, wing

Procedia PDF Downloads 279

Authors: Anuruddha Jayasuriya, Thanakorn Pheeraphan

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In this paper, a review of different mathematical models which can be used as prediction tools to assess the time to crack reinforced concrete (RC) due to corrosion is investigated. This investigation leads to an experimental study to validate a selected prediction model. Most of these mathematical models depend upon the mechanical behaviors, chemical behaviors, electrochemical behaviors or geometric aspects of the RC members during a corrosion process. The experimental program is designed to verify the accuracy of a well-selected mathematical model from a rigorous literature study. Fundamentally, the experimental program exemplifies both one-dimensional chloride diffusion using RC squared slab elements of 500 mm by 500 mm and two-dimensional chloride diffusion using RC squared column elements of 225 mm by 225 mm by 500 mm. Each set consists of three water-to-cement ratios (w/c); 0.4, 0.5, 0.6 and two cover depths; 25 mm and 50 mm. 12 mm bars are used for column elements and 16 mm bars are used for slab elements. All the samples are subjected to accelerated chloride corrosion in a chloride bath of 5% (w/w) sodium chloride (NaCl) solution. Based on a pre-screening of different models, it is clear that the well-selected mathematical model had included mechanical properties, chemical and electrochemical properties, nature of corrosion whether it is accelerated or natural, and the amount of porous area that rust products can accommodate before exerting expansive pressure on the surrounding concrete. The experimental results have shown that the selected model for both one-dimensional and two-dimensional chloride diffusion had ±20% and ±10% respective accuracies compared to the experimental output. The half-cell potential readings are also used to see the corrosion probability, and experimental results have shown that the mass loss is proportional to the negative half-cell potential readings that are obtained. Additionally, a statistical analysis is carried out in order to determine the most influential factor that affects the time to corrode the reinforcement in the concrete due to chloride diffusion. The factors considered for this analysis are w/c, bar diameter, and cover depth. The analysis is accomplished by using Minitab statistical software, and it showed that cover depth is the significant effect on the time to crack the concrete from chloride induced corrosion than other factors considered. Thus, the time predictions can be illustrated through the selected mathematical model as it covers a wide range of factors affecting the corrosion process, and it can be used to predetermine the durability concern of RC structures that are vulnerable to chloride exposure. And eventually, it is further concluded that cover thickness plays a vital role in durability in terms of chloride diffusion.

Keywords: accelerated corrosion, chloride diffusion, corrosion cracks, passivation layer, reinforcement corrosion

Procedia PDF Downloads 186

Authors: Abdelrahman Elsehsah, Hany Madkour, Khalid Farah

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This article presents a 3-D modified non-linear elastic model in the strain space. The Helmholtz free energy function is introduced with the existence of a dissipation potential surface in the space of thermodynamic conjugate forces. The constitutive equation and the damage evolution were derived as well. The modified damage has been examined to model the nonlinear behavior of reinforced concrete (RC) slabs with an opening. A parametric study with RC was carried out to investigate the impact of different factors on the behavior of RC slabs. These factors are the opening area, the opening shape, the place of opening, and the thickness of the slabs. And the numerical results have been compared with the experimental data from literature. Finally, the model showed its ability to be applied to the structural analysis of RC slabs.

Keywords: damage mechanics, 3-D numerical analysis, RC, slab with opening

Procedia PDF Downloads 150

Authors: Nabila Ihaddadene, Razika Ihaddadene, Abdelwahaab Betka

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1973 energy crisis (rising oil prices) pushed the world to consider other alternative energy resources to existing conventional energies consisting predominantly of hydrocarbons. Renewable energies such as solar, the wind and geothermal have received renewed interest, especially to preserve nature ( the low-temperature rise of global environmental problems). Solar energy as an available, cheap and environmental friendly alternative source has various applications such as heating, cooling, drying, power generation, etc. In short, there is no life on earth without this enormous nuclear reactor, called the sun. Among available solar collector designs, flat plate collector (FPC) is low-temperature applications (heating water, space heating, etc.) due to its simple design and ease of manufacturing. Flat plate collectors are permanently fixed in position and do not track the sun (non-concentrating collectors). They operate by converting solar radiation into heat and transferring that heat to a working fluid (usually air, water, water plus antifreeze additive) flowing through them. An FPC generally consists of the main following components: glazing, absorber plate of high absorptivity, fluid tubes welded to or can be an integral part of the absorber plate, insulation and container or casing of the above-mentioned components. Insulation is of prime importance in thermal applications. There are three main families of insulation: mineral insulation; vegetal insulation and synthetic organic insulation. The old houses of the inhabitants of North Africa were built of brick made of composite material that is clay and straw. These homes are characterized by their thermal comfort; i.e. the air inside these houses is cool in summer and warm in winter. So, the material composed from clay and straw act as a thermal insulation. In this research document, the polystyrene used as insulation in the ET200 flat plate solar collector is replaced by the cheapest natural material which is clay and straw. Trials were carried out on a solar energy demonstration system (ET 200). This system contains a solar collector, water storage tank, a high power lamp simulating solar energy and a control and command cabinet. In the experimental device, the polystyrene is placed under the absorber plate and in the edges of the casing containing the components of the solar collector. In this work, we have replaced the polystyrene of the edges by the composite material. The use of the clay and straw as insulation instead of the polystyrene increases temperature difference (T2-T1) between the inlet and the outlet of the absorber by 0.9°C; thus increases the useful power transmitted to water in the solar collector. Tank Water is well heated when using the clay and straw as insulation. However, it is less heated when using the polystyrene as insulation. Clay and straw material improves also the performance of the solar collector by 5.77%. Thus, it is recommended to use this cheapest non-polluting material instead of synthetic insulation to improve the performance of the solar collector.

Keywords: clay, insulation material, polystyrene, solar collector, straw

Procedia PDF Downloads 433

Authors: Jaypalsinh Parmar, Pintu Nakrani, Bhaumik Shah

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Digital Elevation Model (DEM) is elevation data of the virtual grid on the ground. DEM can be used in application in GIS such as hydrological modelling, flood forecasting, morphometrical analysis and surveying etc.. For morphometrical analysis the stream flow network plays a very important role. DEM lacks accuracy and cannot match field data as it should for accurate results of morphometrical analysis. The present study focuses on comparing the Agree method and the conventional Shortest path method for finding out morphometric parameters in the flat region of the Lower Tapi Basin which is located in the western India. For the present study, open source SRTM (Shuttle Radar Topography Mission with 1 arc resolution) and toposheets issued by Survey of India (SOI) were used to determine the morphometric linear aspect such as stream order, number of stream, stream length, bifurcation ratio, mean stream length, mean bifurcation ratio, stream length ratio, length of overland flow, constant of channel maintenance and aerial aspect such as drainage density, stream frequency, drainage texture, form factor, circularity ratio, elongation ratio, shape factor and relief aspect such as relief ratio, gradient ratio and basin relief for 53 catchments of Lower Tapi Basin. Stream network was digitized from the available toposheets. Agree DEM was created by using the SRTM and stream network from the toposheets. The results obtained were used to demonstrate a comparison between the two methods in the flat areas.

Keywords: agree method, morphometric analysis, lower Tapi basin, shortest path method

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Authors: Maryam Bakhtyar-Pegah Akrami

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The relationship between spiritual health and spirituality is one of the important is that in recent years, the research about it is expanding and due to the rich heritage of the in this field of study and research in this important field more than before and we will come to spiritual life and healthier than before. In this research, we provide the following and the basics of Islamic Mysticism in the realm of spiritual health thoughts. This research is based on a descriptive method and comparison with analytical-method to data collected. The findings show that human beings due to this pivotal topic of full Islamic slab, and mental and physical education with the sought to reach the human place are complete, we can provide the basics along with new discussions of spiritual health help human beings to spiritual education along with our faiths in the reconstruction of the spiritual foundations of spiritual health are extremely helpful

Keywords: spirituality, health, Islam, mysticism, perfect human

Procedia PDF Downloads 136

Authors: Chang-Fa Liu, Yi-Ting Wang, Yuan Liu, Hai-Feng Wei, Lei Fang, Jin Li

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Heavy metals in sediments can cause adverse ecological effects while it exceeds a given criteria. The present study investigated sediment environmental quality, pollutant enrichment, ecological risk, and source identification for copper, cadmium, lead, zinc, mercury, and arsenic in the sediments collected from tidal flat marsh of Shuangtai estuary, China. The arithmetic mean integrated pollution index, geometric mean integrated pollution index, fuzzy integrated pollution index, and principal component score were used to characterize sediment environmental quality; fuzzy similarity and geo-accumulation Index were used to evaluate pollutant enrichment; correlation matrix, principal component analysis, and cluster analysis were used to identify source of pollution; environmental risk index and potential ecological risk index were used to assess ecological risk. The environmental qualities of sediment are classified to very low degree of contamination or low contamination. The similar order to element background of soil in the Liaohe plain is region of Sanjiaozhou, Honghaitan, Sandaogou, Xiaohe by pollutant enrichment analysis. The source identification indicates that correlations are significantly among metals except between copper and cadmium. Cadmium, lead, zinc, mercury, and arsenic will be clustered in the same clustering as the first principal component. Copper will be clustered as second principal component. The environmental risk assessment level will be scaled to no risk in the studied area. The order of potential ecological risk is As > Cd > Hg > Cu > Pb > Zn.

Keywords: ecological risk assessment, heavy metals, sediment, marsh, Shuangtai estuary

Procedia PDF Downloads 320

Authors: Meng-Jie Hsiao, Cam Nguyen

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Wide-band devices in Ku band (12-18 GHz) and K band (18-27 GHz) have received significant attention for high-data-rate communications and high-resolution sensing. Especially, devices operating around 24 GHz is attractive due to the 24-GHz unlicensed applications. One of the most important components in RF systems is power amplifier (PA). Various PAs have been developed in the Ku and K bands on GaAs, InP, and silicon (Si) processes. Although the PAs using GaAs or InP process could have better power handling and efficiency than those realized on Si, it is very hard to integrate the entire system on the same substrate for GaAs or InP. Si, on the other hand, facilitates single-chip systems. Hence, good PAs on Si substrate are desirable. Especially, Si-based PA having good linearity is necessary for next generation communication protocols implemented on Si. We report a 16.5 to 25.5 GHz Si-based PA having flat saturated power of 19.5 ± 1.5 dBm, output 1-dB power compression (OP1dB) of 16.5 ± 1.5 dBm, and 15-23 % power added efficiency (PAE). The PA consists of a drive amplifier, two main amplifiers, and lump-element Wilkinson power divider and combiner designed and fabricated in TowerJazz 0.18µm SiGe BiCMOS process having unity power gain frequency (fMAX) of more than 250 GHz. The PA is realized as a cascode amplifier implementing both heterojunction bipolar transistor (HBT) and n-channel metal–oxide–semiconductor field-effect transistor (NMOS) devices for gain, frequency response, and linearity consideration. Particularly, a body-floating technique is utilized for the NMOS devices to improve the voltage swing and eliminate parasitic capacitances. The developed PA has measured flat gain of 20 ± 1.5 dB across 16.5-25.5 GHz. At 24 GHz, the saturated power, OP1dB, and maximum PAE are 20.8 dBm, 18.1 dBm, and 23%, respectively. Its high performance makes it attractive for use in Ku/K-band, especially 24 GHz, communication and radar systems. This paper was made possible by NPRP grant # 6-241-2-102 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Keywords: power amplifiers, amplifiers, communication systems, radar systems

Procedia PDF Downloads 84

Authors: Sonia Besbes, Mahmoud El Hajem, Habib Ben Aissia, Jean Yves Champagne, Jacques Jay

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In this work, we present a computational study for the characterization of the flow in a rectangular bubble column. To simulate the dynamic characteristics of the flow, a three-dimensional transient numerical simulations based on a coupled discrete phase model (DPM) and Volume of Fluid (VOF) model are performed. Modeling of bubble column reactor is often carried out under the assumption of a flat liquid surface with a degassing boundary condition. However, the dynamic behavior of the top surface surmounting the liquid phase will to some extent influence the meandering oscillations of the bubble plume. Therefore it is important to capture the surface behavior, and the assumption of a flat surface may not be applicable. So, the modeling approach needs to account for a dynamic liquid surface induced by the rising bubble plume. The volume of fluid (VOF) model was applied for the liquid and top gas which both interacts with bubbles implemented with a discrete phase model. This model treats the bubbles as Lagrangian particles and the liquid and the top gas as Eulerian phases with a sharp interface. Two-way coupling between Eulerian phases and Lagrangian bubbles are accounted for in a single set continuous phase momentum equation for the mixture of the two Eulerian phases. The effect of gas flow rate on the dynamic and time-averaged flow properties was studied. The time averaged liquid velocity field predicted from simulations and from our previous PIV measurements shows that the liquid is entrained up flow in the wake of the bubbles and down flow near the walls. The simulated and measured vertical velocity profiles exhibit a reasonable agreement looking at the minimum velocity values near the walls and the maximum values at the column center.

Keywords: bubble column, computational fluid dynamics (CFD), coupled DPM and VOF model, hydrodynamics

Procedia PDF Downloads 349

Authors: Adel Khorramrouz, Monireh Ahmadi Bani, Ehsan Norouzi, Morvarid Lalenoor

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Background: Plantar pressure distribution measurement has been used for a long time to assess foot disorders. Plantar pressure is an important component affecting the foot and ankle function and Changes in plantar pressure distribution could indicate various foot and ankle disorders. Morphologic and mechanical properties of the foot may be important factors affecting the plantar pressure distribution. Accurate and early measurement may help to reduce the prevalence of pes planus. With recent developments in technology, new techniques such as machine learning have been used to assist clinicians in predicting patients with foot disorders. Significance of the study: This study proposes a neural network learning-based flat foot classification methodology using static foot pressure distribution. Methodologies: Data were collected from 895 patients who were referred to a foot clinic due to foot disorders. Patients with pes planus were labeled by an experienced physician based on clinical examination. Then all subjects (with and without pes planus) were evaluated for static plantar pressures distribution. Patients who were diagnosed with the flat foot in both feet were included in the study. In the next step, the leg length was normalized and the network was trained for plantar pressure mapping images. Findings: From a total of 895 image data, 581 were labeled as pes planus. A computational neural network (CNN) ran to evaluate the performance of the proposed model. The prediction accuracy of the basic CNN-based model was performed and the prediction model was derived through the proposed methodology. In the basic CNN model, the training accuracy was 79.14%, and the test accuracy was 72.09%. Conclusion: This model can be easily and simply used by patients with pes planus and doctors to predict the classification of pes planus and prescreen for possible musculoskeletal disorders related to this condition. However, more models need to be considered and compared for higher accuracy.

Keywords: foot disorder, machine learning, neural network, pes planus

Procedia PDF Downloads 326

Authors: Emre Alan, Yusuf Yamanturk, Gokay Bas

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Non-grain oriented electrical steels are high silicon containing steels in which the direction of magnetism is intended the same in any direction of the material. Major applications of non-grain-oriented electrical steels are electrical motors, generators, etc. where low magnetic losses are required. Selection of proper hot rolling process parameters is an important factor in order to produce a material that has desired magnetic properties. In this study, the effect of finishing and coiling temperatures on magnetic properties of Fe-3%Si non-grain oriented electrical steels will be investigated. Additionally, the effect of slab reheating temperature at same entry finishing temperature will be investigated by means of reduction in roughing mill pass number from 1-5 to 1-3.

Keywords: electrical steels, hot rolling, magnetic properties, roughing mill

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Authors: Farhat Imtiaz, Umar Farooq

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In this work, we developed a computational model to predict ply level failure in impacted composite laminates. Data obtained from physical testing from flat and round nose impacts of 8-, 16-, 24-ply laminates were considered. Routine inspections of the tested laminates were carried out to approximate ply by ply inflicted damage incurred. Plots consisting of load–time, load–deflection, and energy–time history were drawn to approximate the inflicted damages. Impact test generated unwanted data logged due to restrictions on testing and logging systems were also filtered. Conventional filters (built-in, statistical, and numerical) reliably predicted load thresholds for relatively thin laminates such as eight and sixteen ply panels. However, for relatively thick laminates such as twenty-four ply laminates impacted by flat nose impact generated clipped data which can just be de-noised using oscillatory algorithms. The literature search reveals that modern oscillatory data filtering and extrapolation algorithms have scarcely been utilized. This investigation reports applications of filtering and extrapolation of the clipped data utilising fast Fourier Convolution algorithm to predict load thresholds. Some of the results were related to the impact-induced damage areas identified with Ultrasonic C-scans and found to be in acceptable agreement. Based on consistent findings, utilizing of modern data filtering and extrapolation algorithms to data logged by the existing machines has efficiently enhanced data interpretations without resorting to extra resources. The algorithms could be useful for impact-induced damage approximations of similar cases.

Keywords: fibre reinforced laminates, fast Fourier algorithms, mechanical testing, data filtering and extrapolation

Procedia PDF Downloads 112

Authors: Ahmed E. Hodaib, Mohamed A. Hashem

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Dissimilar to pneumatic tyres, airless tyres or flat-proof tyres (also known as tweel) is designed to have poly-composite compound treaded around a hub of flexible spokes. The main advantage of this design is its robustness as airless tyres are impossible to deflate or to blowout at highway speeds like conventional tyres so the driver does not have to be restless about having a spare tire. A summary of the study on manufacturing of airless tyres’ mold is given. Moreover, we have proposed some advantages and disadvantages of using tweel tyres.

Keywords: airless tyres, tweel, non-pneumatic tyres, manufacturing

Procedia PDF Downloads 465

Authors: F. Bouzeboudja, K. Ait-Tahar

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The method of strengthening of concrete works by composite materials is a practice which knows currently an important development. From this perspective, we propose to make a contribution to the analysis of the behavior of concrete slabs reinforced with composite fabrics, arranged in parallel folds according to the thickness of the slab. The analysis of experimentally obtained modes of failure confirms, generally, that the ruin of the structure occurs essentially by punching. Accordingly, our work is directed to the analysis of the behavior of reinforced slabs towards the punching. An experimental investigation is realized. For that purpose, a set of trial specimens was made. The reinforced specimens are subjected to an essay of punching, by making vary the direction of the eccentricity. The first experimental results show that the ultimate loads, as well as the transition from the flexion failure mode to the punching failure mode, are governed essentially by the eccentricity.

Keywords: composites, concrete slabs, failure, laminate, punching

Procedia PDF Downloads 211

Authors: P. Brunne, K. Ciechowska, K. Gajc, K. Gawin, M. Gawin, M. Kania, J. Kindracki, Z. Kusznierewicz, D. Pączkowska, F. Perczyński, K. Pilarski, D. Rafało, E. Ryszawa, M. Sobiecki, I. Uwarowa

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Big amount of space debris constitutes nowadays a real thread for operating space crafts; therefore the main purpose of PW-Sat2’ team was to create a system that could help cleanse the Earth’s orbit after each small satellites’ mission. After 4 years of development, the motorless, low energy consumption and low weight system has been created. During series of tests, the system has shown high reliable efficiency. The PW-Sat2’s deorbit system is a square-shaped sail which covers an area of 4m². The sail surface is made of 6 μm aluminized Mylar film which is stretched across 4 diagonally placed arms, each consisting of two C-shaped flat springs and enveloped in Mylar sleeves. The sail is coiled using a special, custom designed folding stand that provides automation and repeatability of the sail unwinding tests and placed in a container with inner diameter of 85 mm. In the final configuration the deorbit system weights ca. 600 g and occupies 0.6U (in accordance with CubeSat standard). The sail’s releasing system requires minimal amount of power based on thermal knife that burns out the Dyneema wire, which holds the system before deployment. The Sail is being pushed out of the container within a safe distance (20 cm away) from the satellite. The energy for the deployment is completely assured by coiled C-shaped flat springs, which during the release, unfold the sail surface. To avoid dynamic effects on the satellite’s structure, there is the rotational link between the sail and satellite’s main body. To obtain complete knowledge about complex dynamics of the deployment, a number of experiments have been performed in varied environments. The numerical model of the dynamics of the Sail’s deployment has been built and is still under continuous development. Currently, the integration of the flight model and Deorbit Sail is performed. The launch is scheduled for February 2018. At the same time, in cooperation with United Nations Office for Outer Space Affairs, sail models and requested facilities are being prepared for the sail deployment experiment under micro-gravity and low pressure conditions at Bremen Drop Tower, Germany. Results of those tests will provide an ultimate and wide knowledge about deployment in space environment to which system will be exposed during its mission. Outcomes of the numerical model and tests will be compared afterwards and will help the team in building a reliable and correct model of a very complex phenomenon of deployment of 4 c-shaped flat springs with surface attached. The verified model could be used inter alia to investigate if the PW-Sat2’s sail is scalable and how far is it possible to go with enlarging when creating systems for bigger satellites.

Keywords: cubesat, deorbitation, sail, space, debris

Procedia PDF Downloads 265

Authors: Kangkang Tang

Abstract:

A large amount of blast furnace slag is generated in China. Most ground granulated blast furnace slag (GGBS) however ends up in low-grade applications. Blast furnace slag, ground to an appropriate fineness, can be used as a partial replacement of cementitious material in concrete. The potential for using GGBS in structural concrete, e.g. concrete beams and columns, is investigated at Xi’an Jiaotong-Liverpool University (XJTLU). With 50% of CEM I replaced with GGBS, peak hydration temperatures determined in a suspended concrete slab reduced by 20%. This beneficiary effect has not been further improved with 70% of CEM I replaced with GGBS. Partial replacement of CEM I with GGBS also has a retardation effect on the early-age strength of concrete. More GGBS concrete mixes will be conducted to identify an ‘optimum’ replacement level which will lead to a reduced thermal loading, without significantly compromising the early-age strength of concrete.

Keywords: thermal effect, GGBS, concrete strength and testing, sustainability

Procedia PDF Downloads 372

Authors: Waqas Ashraf, Yasir Nawab, Haritham Khan, Habib Awais, Shahbaz Ahmad

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Seersucker is a popular lightweight fabric widely used in men’s and women’s suiting, casual wear, children’s clothing, house robes, bed spreads and for spring and summer wear. The puckered effect generates air spaces between body and the fabric, keeping the wearer cool in hot conditions. The aim of this work was to develop knitted seersucker fabric on single cylinder weft knitting machine using plain jersey structure. Core spun cotton yarn and cotton spun yarn of same linear density were used. Core spun cotton yarn, contains cotton fiber in the sheath and elastase filament in the core. The both yarn were fed at regular interval to feeders on the machine. The loop length and yarn tension were kept constant at each feeder. The samples were then scoured and bleached. After wet processing, the fabric samples were washed and tumble dried. Parameters like loop length, stitch density and areal density were measured after conditioning these samples for 24 hours in Standard atmospheric condition. Produced sample has a regular puckering stripe along the width of the fabric with same height. The stitch density of both the flat and puckered area of relaxed fabric was found to be different .Air permeability and moisture management tests were performed. The results indicated that the knitted seersucker fabric has better wicking and moisture management properties as the flat area contact, whereas puckered area held away from the skin. Seersucker effect in knitted fabric was achieved by the difference of contraction of both sets of courses produced from different types of yarns. The seer sucker fabric produce by knitting technique is less expensive as compared to woven seer sucker fabric as there is no need of yarn preparation. The knitted seersucker fabric is more practicable for summer dresses, skirts, blouses, shirts, trousers and shorts.

Keywords: air permeability, knitted structure, moisture management, seersucker

Procedia PDF Downloads 294