Search results for: soil strength

Authors: Rahman Davtalab

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Florida is one of the most vulnerable states to natural disasters among the 50 states of the USA. The state exposed by tropical storms, hurricanes, storm surge, landslide, etc. Besides, the mentioned natural phenomena, global warming, sea-level rise, and other anthropogenic environmental changes make a very complicated and unpredictable system for decision-makers. In this study, we tried to highlight the effects of climate change and sea-level rise on surface water and groundwater systems for three different geographical locations in Florida; Main Canal of Jacksonville Beach (in the northeast of Florida adjacent to the Atlantic Ocean), Grace Lake in central Florida, far away from surrounded coastal line, and Mc Dill in Florida and adjacent to Tampa Bay and Mexican Gulf. An integrated hydrologic and hydraulic model was developed and simulated for all three cases, including surface water, groundwater, or a combination of both. For the case study of Main Canal-Jacksonville Beach, the investigation showed that a 76 cm sea-level rise in time horizon 2060 could increase the flow velocity of the tide cycle for the main canal's outlet and headwater. This case also revealed how the sea level rise could change the tide duration, potentially affecting the coastal ecosystem. As expected, sea-level rise can raise the groundwater level. Therefore, for the Mc Dill case, the effect of groundwater rise on soil storage and the performance of stormwater retention ponds is investigated. The study showed that sea-level rise increased the pond’s seasonal high water up to 40 cm by time horizon 2060. The reliability of the retention pond is dropped from 99% for the current condition to 54% for the future. The results also proved that the retention pond could not retain and infiltrate the designed treatment volume within 72 hours, which is a significant indication of increasing pollutants in the future. Grace Lake case study investigates the effects of climate change on groundwater recharge. This study showed that using the dynamically downscaled data of the groundwater recharge can decline up to 24% by the mid-21st century.

Keywords: groundwater, surface water, Florida, retention pond, tide, sea level rise

Procedia PDF Downloads 185

Authors: Ahmet Kurklu, Abdussamed Sarp, Gokmen Arikan, Akin Eren, Arif Ulu, Ferit Cakir

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Our natural resources are diminishing day by day with the needs of the growing world population. There is a danger that these resources will be depleted if they are not used in a controlled manner. As a result of the rapid increase in the consumption of limited natural resources, one of the issues where studies have gained importance is recycling. Many countries have carried out various research and development activities on recycling and reuse to prevent wastage of resources. For sustainable and healthy living, the limited amount of raw material resources in nature should be consumed consciously, and the necessary awareness should be given for recycling activities. One of the sectors where the consumption of raw materials is high is the construction sector. With the changing consumption habits of the evolving technology in the construction sector, the need to use special concrete along with the normal concrete has arisen. With the increasing need for specialty concretes, polymer concrete, which was discovered in the early 1900s, has evolved to the present day. Polymer concretes are special concretes with high strength, water impermeability, resistance to chemical action, and low surface roughness. Thanks to these properties, they find wide applications in many fields such as swimming pools, drainage systems, repair works. In the study, the effect of using recycled aggregates instead of natural aggregates in the production of polymer concrete on the performance of polymer concrete is investigated. In the experiments conducted for this purpose, the use of natural aggregate is reduced at certain rates, and instead, recycled aggregate is added at the same rate. The recycled aggregate to be used in the study is obtained from the polymer concrete drainage channel production facility of Mert Casting Co., Istanbul, Turkey. In order to clearly observe the effect of recycled materials on the product in the study, the other components (resin, hardener, accelerator, and additive) are kept constant in the concrete mix. In the study, fresh and hardened concrete tests are to be carried out on the mixes to be prepared.

Keywords: concrete, mechanical properties, polymer concrete, recycle aggregate

Procedia PDF Downloads 144

Authors: Altilio Rosa, Chirico Francesco, Foglia Goffredo

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In recent years, the number of Unmanned Aerial Vehicles (UAVs) has significantly increased. The rapid development of commercial and recreational drones makes them an important part of our society. Despite the growing list of their applications, these vehicles pose a huge threat to civil and military installations: detection, classification and neutralization of such flying objects become an urgent need. Radar is an effective remote sensing tool for detecting and tracking flying objects, but scenarios characterized by the presence of a high number of tracks related to flying birds make especially challenging the drone detection task: operator PPI is cluttered with a huge number of potential threats and his reaction time can be severely affected. Flying birds compared to UAVs show similar velocity, RADAR cross-section and, in general, similar characteristics. Building from the absence of a single feature that is able to distinguish UAVs and birds, this paper uses a multiple features approach where an original feature selection technique is developed to feed binary classifiers trained to distinguish birds and UAVs. RADAR tracks acquired on the field and related to different UAVs and birds performing various trajectories were used to extract specifically designed target movement-related features based on velocity, trajectory and signal strength. An optimization strategy based on a genetic algorithm is also introduced to select the optimal subset of features and to estimate the performance of several classification algorithms (Neural network, SVM, Logistic regression…) both in terms of the number of selected features and misclassification error. Results show that the proposed methods are able to reduce the dimension of the data space and to remove almost all non-drone false targets with a suitable classification accuracy (higher than 95%).

Keywords: birds, classification, machine learning, UAVs

Procedia PDF Downloads 221

Authors: Oiane Ruiz de Azua, Salvador Borros, Nuria Agullo, Jordi Arbusa

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Tackiness is described as the ability to spontaneously form a bond to another material under light pressures within a short application time. During the first few minutes of the adhesive's curing, it is necessary to have enough tack to keep the substrates together while cohesion is increasing within the adhesive. This property plays a key role in the manufacturing process of pieces. Epoxy adhesives, unlike other adhesives, usually present low tackiness before curing; however, there is very little literature about the use of tackifiers in epoxy adhesives, except for the high molecular weight epoxy additives. In the present work, a tetrafunctional epoxy resin based on Bisphenol-A and Sulfanilamide has been synthesized in order to be used as a tackifier. This additive offers improved specific adhesion to two-component (2K) epoxy adhesives. The dosage of the tackifier has to be done carefully not to alter the mechanical and rheological properties of the adhesive. The synthetized product has been analyzed by FTIR and ¹H-NMR analysis, and the effect of the addition of 1 wt % of the tackifier on rheological properties, viscoelastic behavior, and mechanical properties has been studied. On one hand, the addition of the product in the epoxy resin part showed a significant increase in tackiness regarding the neat epoxy resin. On the other hand, tackiness of the whole formulation was also increased. Curing time of the adhesive has not undergone any relevant changes with the tackifier addition. Regarding viscoelastic properties, Storage Modulus (G') and Loss Modulus (G'') remain also unchanged at ambient temperature. Probably, in case higher tackifier concentration would be added, differences in viscoelastic properties would be observed. The study of mechanical properties shows that hardness and tensile strength also keep their values unchanged regarding neat two component adhesive. In conclusion, the addition of 1 wt % of sulfanilamide/epoxy enhanced the tackiness of the epoxy resin part, improves tack without modifying significantly either the rheological, the mechanical, or the viscoelastic properties of the product. Thus, the sulfanilamide presented could be a good candidate to be used as an additive to the 2k epoxy formulation for the manufacturing process of pieces.

Keywords: epoxy adhesive, manufacturing process of pieces, sulfanilamide, tackifiers

Procedia PDF Downloads 183

Authors: Cristina-Corina Bențea, Teodora-Mihaela Iconomescu, Laurențiu-Gabriel Talaghir, Claudiu Mereuță, Anamaria Berdilă

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The study aims to examine the relationships between motor abilities, self-evaluation of athletic competence, and demographic characteristics in a sample of late-childhood participants. Defined as physical elements that enable the movements, motor skills are classified according to movement precision as gross and fine motor skills. Across their development, children enhance their ability to coordinate the limbs to produce different actions. In educational settings, they perform various instructional activities that involve the improvement of their athletic prowess and are taught how to strengthen their gross and fine motor abilities. Also, in relation to their activities, children tend to evaluate themselves differently across the various domains of their life. Starting from childhood, athletic competence is one of the area-specific evaluations of competence that refers to one’s ability to do well at sports, including outdoor games. Method: The sample consisted of fifty-eight primary school children, thirty girls, and twenty-eight boys, with ages between 8-10 years. The Bruininks-Oseretsky test of motor proficiency was used to assess both gross and fine motor skills in eight specific areas (fine motor precision, fine motor integration, manual dexterity, bilateral coordination, balance, running speed and agility, upper-limb coordination, strength). Athletic competence self-perceived was assessed with one of the six subscales of the Self-Perception Profile for Children. Results: Were examined both the relationships between each motor skills scale and subscales and between motor skills and general self-perceived athletic competence. Results indicated correlations between the athletic competence and four motor skills subscales depending on the gender and age of the children. The findings of the study were discussed related to the possibility to improve children's physical proficiency in educational settings according to the level of self-perceived athletic competence.

Keywords: gross motor skills, fine motor skills, athletic competence, self-evaluation, children, education

Procedia PDF Downloads 85

Authors: Apoorva Bamal, Agnieszka Indiana Olbert

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Floods are known to be one of the most devastating hydro-climatic events, impacting a wide range of stakeholders in terms of environmental, social and economic losses. With difference in inundation durations and level of impact, flood hazards are of different degrees and strength. Amongst various set of domains being impacted by floods, environmental degradation in terms of water quality deterioration is one of the majorly effected but less highlighted domains across the world. The degraded water quality is caused by numerous natural and anthropogenic factors that are both point and non-point sources of pollution. Therefore, it is essential to understand the nature and source of the water pollution due to flooding. The major impact of floods is not only on the physico-chemical water quality parameters, but also on the biological elements leading to a vivid influence on the aquatic ecosystem. This deteriorated water quality is impacting many water categories viz. agriculture, drinking water, aquatic habitat, and miscellaneous services requiring an appropriate water quality to survive. This study identifies, reviews, evaluates and assesses multiple researches done across the world to determine the impact of floods on water quality. With a detailed statistical analysis of top relevant researches, this study is a synopsis of the methods used in assessment of impact of floods on water quality in different geographies, and identifying the gaps for further abridgement. As per majority of the studies, different flood magnitudes have varied impact on the water quality parameters leading to either increased or decreased values as compared to the recommended values for various categories. There is also an evident shift of the biological elements in the impacted waters leading to a change in its phenology and inhabitants of the specified water body. This physical, chemical and biological water quality degradation by floods is dependent upon its duration, extent, magnitude and flow direction. Therefore, this research provides an overview into the multiple impacts of floods on water quality, along with a roadmap of way forward to an efficient and uniform linkage of floods and impacted water quality dynamics.

Keywords: floods, statistical analysis, water pollution, water quality

Procedia PDF Downloads 81

Authors: Ghazi Abdul Rehman Qasmi

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Islam is the preacher and torch-bearer of unity and solidarity. All the followers of Islam are advised to be united. Islam strongly condemns those elements which disunite the unity of Muslim Ummah. Like pearls in a rosary, Islam has united the Muslims from all over the world in the wreath of unity and forbade the Muslims to avoid separation and to be disintegrated. The aspect of unity is prominent in all divine injunctions and about worship. By offering five times obligatory congregational prayers, passion of mutual love and affection is increased and on the auspicious days like Friday, Eid-ul-fiter and Eid-ul-azha, majority of the Muslims come together at central places to offer these congregational prayers. Thus unity and harmony among the Muslims can be seen. Similarly the Muslim pilgrims from all over the world eliminate all kind of worldly discrimination to perform many rituals of pilgrimage while wearing white color cloth as a dress. Pilgrimage is a demonstration of Islamic strength. When the Muslims from all over the world perform the same activities together and they offer their prayers under the leadership of one leader (IMAM). Muslims come together on the occasion of pilgrimage to perform Tawaf (seven circuits,first three circuits at a hurried pace(Rammal) and followed by four times, more closely, at a leisurely pace, round the Holy Kaabah to perform circumambulation known as Tawaf in religious terminology,Saee(running or walking briskly seven times between two small hills Safa&Marwa), Ramy-al-jamarat (throwing pebbles at the stone pillars, symbolizing the devil). In this way dignity and sublimity of Islam is increased and unity and integrity of Muslim Ummah is promoted also. By studying the life history of Hazrat Muhammad (P.B.U.H) we come to know that our Holy Prophet (P.B.U.H) has put emphasis on unity and integrity. We have to follow the Islamic teachings to create awareness among the members of Muslim Ummah. In the light of the Holy Quran and Sunnah, we have to utilize all the sources and potential for this noble cause.

Keywords: unity, Ummah, sources, Islamic teaching

Procedia PDF Downloads 294

Authors: Mohamed Gherbi

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The informal trade has invaded the Algerian cities, especially in their peripherals. About 1368 informal markets have been registrated during 2013 where the important ones are known by Doubaï Markets. They appeared since the adoption of the new system of the economy market in 1990. It permitted the intervention of new actors: the importers but also the fake ones. The majority of them were 'ex-Trabendistes' who have chosen to settle and invest in big and small cities of center and east of Algeria, mainly Algiers, El Eulma, Aïn El Fekroun, Tadjnenent, and Aïn M’lila. This study will focus on the case of the city of El Eulma which contains more of 1000 importers (most of them are fake). They have changed the image and architecture of some important streets of the city, without respecting rules of urbanism such as those included in the building permit for instance. The case of 'Doubaï' place in El Eulma illustrates this situation. This area is not covered by a Soil Occupation Plan (responsible of the design of urban spaces), even if this last covers other zones nearby surrounding of it. These importers helped by the wholesale and retail traders installed in 'Doubaï' place, have converted spaces inside and outside of residential buildings in deposits and sales of goods. They have squatted sidewalks to expose their goods imported predominantly from the South-East Asian countries. The scenery that reigns resembles partly to the bazaar of the Middle East and Chinese cities like Yiwu. These signs characterize the local ambiance and give the particularity to this part of the city. A customer tide from different cities and outside of Algeria comes daily to visit this district. The other zones surrounding have underwent the same change and have followed the model of 'Doubaï' place. Consequently, the mechanical movement has finished by stifling an important part of the city and the prices of land and real estate have reached exorbitant values and can be compared to prices charged in Paris due to the rampant speculation that has reached alarming dimensions. Similarly, renting commercial premises did not escape this logic. This paper will explain the reasons responsible of this change, the logic of importers through their acts in different spaces of the city.

Keywords: Doubaï place, design of urban spaces, fake importers, informal trade

Procedia PDF Downloads 415

Authors: B. J. Babalola, M. B. Shongwe

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Spark Plasma Sintering technique is a novel processing method that produces limited grain growth and highly dense variety of materials; alloys, superalloys, and carbides just to mention a few. However, initial particle size and spark plasma sintering parameters are factors which influence the grain growth and mechanical properties of sintered materials. Ni-Cr alloys are regarded as the most promising alloys for aerospace turbine blades, owing to the fact that they meet the basic requirements of desirable mechanical strength at high temperatures and good resistance to oxidation. The conventional method of producing this alloy often results in excessive grain growth and porosity levels that are detrimental to its mechanical properties. The effect of sintering temperature was evaluated on the microstructure and mechanical properties of the nanostructured Ni-17Cr alloy. Nickel and chromium powder were milled using high energy ball milling independently for 30 hours, milling speed of 400 revs/min and ball to powder ratio (BPR) of 10:1. The milled powders were mixed in the composition of Nickel having 83 wt % and chromium, 17 wt %. This was sintered at varied temperatures from 800°C, 900°C, 1000°C, 1100°C and 1200°C. The structural characteristics such as porosity, grain size, fracture surface and hardness were analyzed by scan electron microscopy and X-ray diffraction, Archimedes densitometry, micro-hardness tester. The corresponding results indicated an increase in the densification and hardness property of the alloy as the temperature increases. The residual porosity of the alloy reduces with respect to the sintering temperature and in contrast, the grain size was enhanced. The study of the mechanical properties, including hardness, densification shows that optimum properties were obtained for the sintering temperature of 1100°C. The advantages of high sinterability of Ni-17Cr alloy using milled powders and microstructural details were discussed.

Keywords: densification, grain growth, milling, nanostructured materials, sintering temperature

Procedia PDF Downloads 402

Authors: Thomas Nally, Jane Ireland, Roxanne Khan, Philip Birch

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Intimate Partner Violence (IPV), a significant societal problem, affects individuals worldwide. However, the strategies victims use to keep safe are under-researched. IPV is significantly under-reported, and services often are not able to be accessed by all victims. Thus they are likely to use their own strategies to manage their victimization before being able to seek support. Two studies were completed to understand these strategies. A systematic review of the literature and study completed with professionals who work with victims was undertaken to understand this area. In study one, a systematic review of the literature (n=61 papers), were analyzed using Thematic Analysis. The results indicated that victims use a large array of behaviors to increase their sense of safety and coping with emotions but also experience significant barriers to help-seeking. In study 2, sixty-nine professionals completed a measure exploring the likelihood and effectiveness of various victim strategies regarding increasing their sense of safety. Strategies included in the measure were obtained from those identified in study 1. Findings indicated that professionals perceived victims of IPV to be more likely to employ safety strategies and coping behaviors that may be ineffective but not help-seeking behaviors. Further, the responses were analyzed using Cluster Analysis. Safety strategies resulted in five clusters; perpetrator-directed strategies, prevention strategies, cognitive reappraisal, safety planning and avoidance strategies. Help-Seeking resulted in six clusters; information or practical support, abuse-related support, emotional support, secondary support and informal support. Finally, coping resulted in four clusters; emotional coping, self-directed coping, thought recording/change and cognitive coping. Both studies indicate that victims may use a variety of strategies to manage their safety besides seeking help. Professionals working with victims, using a strength-based approach, should understand what is used and is effective for victims who are unable to leave the relationships or access external support.

Keywords: intimate partner violence, help-seeking, professional support, victims, victim coping, victim safety

Procedia PDF Downloads 186

Authors: Fikru Fentaw Abera

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Climate changes alter regional hydrologic conditions and results in a variety of impacts on water resource systems. Such hydrologic changes will affect almost every aspect of human well-being. The goal of this paper is to assess the impact of climate change on the hydrology of Upper Guder catchment located in northwest of Ethiopia. The GCM derived scenarios (HadCM3 A2a & B2a SRES emission scenarios) experiments were used for the climate projection. The statistical downscaling model (SDSM) was used to generate future possible local meteorological variables in the study area. The down-scaled data were then used as input to the soil and water assessment tool (SWAT) model to simulate the corresponding future stream flow regime in Upper Guder catchment of the Abay River Basin. A semi distributed hydrological model, SWAT was developed and Generalized Likelihood Uncertainty Estimation (GLUE) was utilized for uncertainty analysis. GLUE is linked with SWAT in the Calibration and Uncertainty Program known as SWAT-CUP. Three benchmark periods simulated for this study were 2020s, 2050s and 2080s. The time series generated by GCM of HadCM3 A2a and B2a and Statistical Downscaling Model (SDSM) indicate a significant increasing trend in maximum and minimum temperature values and a slight increasing trend in precipitation for both A2a and B2a emission scenarios in both Gedo and Tikur Inch stations for all three bench mark periods. The hydrologic impact analysis made with the downscaled temperature and precipitation time series as input to the hydrological model SWAT suggested for both A2a and B2a emission scenarios. The model output shows that there may be an annual increase in flow volume up to 35% for both emission scenarios in three benchmark periods in the future. All seasons show an increase in flow volume for both A2a and B2a emission scenarios for all time horizons. Potential evapotranspiration in the catchment also will increase annually on average 3-15% for the 2020s and 7-25% for the 2050s and 2080s for both A2a and B2a emissions scenarios.

Keywords: climate change, Guder sub-basin, GCM, SDSM, SWAT, SWAT-CUP, GLUE

Procedia PDF Downloads 364

Authors: Pedro P. Drumond, Priscilla M. Moura, Marcia M. L. P. Coelho

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The purpose of On-site Stormwater Detention (OSD) system is to promote the detention of addition stormwater runoff caused by impervious areas, in order to maintain the peak flow the same as the pre-urbanization condition. In recent decades, these systems have been built in many cities around the world. However, its real efficiency continues to be unknown due to the lack of research, especially with regard to monitoring its real performance. Thus, this study aims to compare the water level monitoring data of an OSD built in Belo Horizonte/Brazil with the results of theoretical methods simulations, usually adopted in OSD design. There were made two theoretical simulations, one using the Rational Method and Modified Puls method and another using the Soil Conservation Service (SCS) method and Modified Puls method. The monitoring data were obtained with a water level sensor, installed inside the reservoir and connected to a data logger. The comparison of OSD performance was made for 48 rainfall events recorded from April/2015 to March/2017. The comparison of maximum water levels in the OSD showed that the results of the simulations with Rational/Puls and SCS/Puls methods were, on average 33% and 73%, respectively, lower than those monitored. The Rational/Puls results were significantly higher than the SCS/Puls results, only in the events with greater frequency. In the events with average recurrence interval of 5, 10 and 200 years, the maximum water heights were similar in both simulations. Also, the results showed that the duration of rainfall events was close to the duration of monitored hydrograph. The rising time and recession time of the hydrographs calculated with the Rational Method represented better the monitored hydrograph than SCS Method. The comparison indicates that the real discharge coefficient value could be higher than 0.61, adopted in Puls simulations. New researches evaluating OSD real performance should be developed. In order to verify the peak flow damping efficiency and the value of the discharge coefficient is necessary to monitor the inflow and outflow of an OSD, in addition to monitor the water level inside it.

Keywords: best management practices, on-site stormwater detention, source control, urban drainage

Procedia PDF Downloads 188

Authors: Md. Jisan Ahmed, M. A. Taher

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One of the cities in Bangladesh that is developing the fastest is Narayanganj City Corporation. In 2011, the municipality of Narayanganj was transformed into a city corporation, with 27 wards combining Kadamrasul Municipality, Siddhirganj Municipality, and Narayanganj Town. It is also one of Bangladesh's most important industrial centers in Bangladesh. Narayanganj City Corporation (NCC), which has had high development growth, is also generating more solid waste on a high per-capita basis. Because of the increasing rate of population expansion, business activity, industrial development, and fast urbanization, NCC is today creating more waste than ever before. The enormous amount of solid garbage produced in NCC is currently causing air pollution, soil contamination, water pollution, drainage system blockages, and an unpleasant urban environment. The study aimed to find out the amount of solid waste produced per day in NCC by exploring the waste composition and potentiality of resource recovery from the produced solid waste. This study considered household surveys, polythene bag surveys, questionnaire surveys in commercial and industrial sectors, KIIs, FGDs, and lab tests to identify the total amount of waste generated in NCC with waste composition and potentiality for energy recovery from the generated waste. This study has explored that NCC is producing about 922 tons of solid waste per day from households, commercial activities, and industrial sectors where the existing waste collection rate by NCC authority is only about 50% of total generated waste. This study has also explored that about 75% of daily-produced solid waste is perishable with comparatively high moisture content whereas 18 % and 7% are non-perishable and hazardous. It is also explored that there is no resource recovery plant for solid waste management in NCC. On the other hand, this study has explored that the calorific value of the produced solid waste favors resource recovery like waste to electricity. The generated solid waste composition is also in favor of waste-to-biogas, and waste-to-compost fertilizer production. This study has advocated that initiatives need to develop a solid waste management plant in NCC for resource recovery from solid waste. This research may provide a quick overview of the rate of solid waste generation, its composition, and the potential for resource recovery from solid waste in Bangladesh's metropolitan regions. It can also provide information and knowledge to other trash departments in different cities and municipalities in Bangladesh.

Keywords: solid waste, waste composition, waste management, resource recovery from solid waste

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Authors: Tichaona Nharingo, Hope Tauya, Mambo Moyo

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Wood ash has been demonstrated to have favourable adsorption capacity for heavy metal ions but suffers the application problem of difficult to separate/isolate from the batch adsorption systems. Fabrication of wood ash beads using multifunctional group and non-toxic carbohydrate, alginate, may improve the applicability of wood ash in environmental pollutant remediation. In this work, alginate-wood ash beads (AWAB) were fabricated and applied to the removal of cadmium ions from aqueous systems. The beads were characterized by FTIR, TGA/DSC, SEM-EDX and their pHZPC before and after the adsorption of Cd(II) ions. Important adsorption parameters i.e. pH, AWAB dosage, contact time and ionic strength were optimized and the effect of initial concentration of Cd(II) ions to the adsorption process was established. Adsorption kinetics, adsorption isotherms, adsorption mechanism and application of AWAB to real water samples spiked with Cd(II) ions were ascertained. The composite adsorbent was characterized by a heterogeneous macro pore surface comprising of metal oxides, multiple hydroxyl groups and carbonyl groups that were involved in electrostatic interaction and Lewis acid-base interactions with the Cd(II) ions. The pseudo second order and the Freundlich isotherm models best fitted the adsorption kinetics and isotherm data respectively suggesting chemical sorption process and surface heterogeneity. The presence of Pb(II) ions inhibited the adsorption of Cd(II) ions (reduced by 40 %) attributed to the competition for the adsorption sites. The Cd(II) loaded beads could be regenerated using 0.1 M HCl and could be applied to four sorption-desorption cycles without significant loss in its initial adsorption capacity. The high maximum adsorption capacity, stability, selectivity and reusability of AWAB make the adsorbent ideal for application in the removal of Cd(II) ions from real water samples. Column type adsorption experiments need to be explored to establish the potential of the adsorbent in removing Cd(II) ions using continuous flow systems.

Keywords: adsorption, Cd(II) ions, regeneration, wastewater, wood ash-alginate beads

Procedia PDF Downloads 245

Authors: Vera Wilden, Benno Hoffmeister, Markus Feldmann

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Glued laminated timber (glulam) is a preferred choice for long span girders, e.g., for gyms or storage halls. While the material provides sufficient strength to resist the bending moments, large spans lead to increased slenderness of such members and to a higher susceptibility to stability issues, in particular to lateral torsional buckling (LTB). Rules for the determination of the ultimate LTB resistance are provided by Eurocode 5. The verifications of the resistance may be performed using the so called equivalent member method or by means of theory 2nd order calculations (direct method), considering equivalent imperfections. Both methods have significant limitations concerning their applicability; the equivalent member method is limited to rather simple cases; the direct method is missing detailed provisions regarding imperfections and requirements for numerical modeling. In this paper, the results of a test series on slender glulam beams in three- and four-point bending are presented. The tests were performed in an innovative, newly developed testing rig, allowing for a very precise definition of loading and boundary conditions. The load was introduced by a hydraulic jack, which follows the lateral deformation of the beam by means of a servo-controller, coupled with the tested member and keeping the load direction vertically. The deformation-controlled tests allowed for the identification of the ultimate limit state (governed by elastic stability) and the corresponding deformations. Prior to the tests, the structural and geometrical imperfections were determined and used later in the numerical models. After the stability tests, the nearly undamaged members were tested again in pure bending until reaching the ultimate moment resistance of the cross-section. These results, accompanied by numerical studies, were compared to resistance values obtained using both methods according to Eurocode 5.

Keywords: experimental tests, glued laminated timber, lateral torsional buckling, numerical simulation

Procedia PDF Downloads 237

Authors: Shima Taheri, Simon Clark

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Concrete is an essential building material used in the majority of structures. Degradation of concrete over time increases the life-cycle cost of an asset with an estimated annual cost of billions of dollars to national economies. Most of the concrete failure occurs due to cracks, which propagate through a structure and cause weakening leading to failure. Stopping crack propagation is thus the key to protecting concrete structures from failure and is the best way to prevent inconveniences and catastrophes. Furthermore, the majority of cracks occur deep within the concrete in inaccessible areas and are invisible to normal inspection. Few materials intrinsically possess self-healing ability, but one that does is concrete. However, self-healing in concrete is limited to small dormant cracks in a moist environment and is difficult to control. In this project, we developed a method for self-healing of nascent fractures in concrete components through the automatic release of self-curing healing agents encapsulated in breakable nano- and micro-structures. The Poly(methyl methacrylate) (PMMA) based two-part adhesive is encapsulated in core-shell structures with brittle/weak inert shell, synthesized via miniemulsion/solvent evaporation polymerization. Stress fields associated with propagating cracks can break these capsules releasing the healing agents at the point where they are needed. The shell thickness is playing an important role in preserving the content until the final setting of concrete. The capsules can also be surface functionalized with carboxyl groups to overcome the homogenous mixing issues. Currently, this formulated self-healing system can replace up to 1% of cement in a concrete formulation. Increasing this amount to 5-7% in the concrete formulation without compromising compression strength and shrinkage properties, is still under investigation. This self-healing system will not only increase the durability of structures by stopping crack propagation but also allow the use of less cement in concrete construction, thereby adding to the global effort for CO2 emission reduction.

Keywords: self-healing concrete, concrete crack, concrete deterioration, durability

Procedia PDF Downloads 117

Authors: May Haggag, Ezzat Fahmy, Mohamed Abdel-Mooty, Sherif Safar

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Sandwich sections have a very complex nature due to variability of behavior of different materials within the section. Cracking, crushing and yielding capacity of constituent materials enforces high complexity of the section. Furthermore, slippage between the different layers adds to the section complex behavior. Conventional methods implemented in current industrial guidelines do not account for the above complexities. Thus, a throughout study is needed to understand the true behavior of the sandwich panels thus, increase the ability to use them effectively and efficiently. The purpose of this paper is to conduct numerical investigation using ANSYS software for the structural behavior of sandwich wall section under eccentric loading. Sandwich walls studied herein are composed of two RC faces, a foam core and linking shear connectors. Faces are modeled using solid elements and reinforcement together with connectors are modeled using link elements. The analysis conducted herein is nonlinear static analysis incorporating material nonlinearity, crashing and crushing of concrete and yielding of steel. The model is validated by comparing it to test results in literature. After validation, the model is used to establish extensive parametric analysis to investigate the effect of three key parameters on the axial force bending moment interaction diagram of the walls. These parameters are the concrete compressive strength, face thickness and number of shear connectors. Furthermore, the results of the parametric study are used to predict a coefficient that links the interaction diagram of a solid wall to that of a sandwich wall. The equation is predicted using the parametric study data and regression analysis. The predicted α was used to construct the interaction diagram of the investigated wall and the results were compared with ANSYS results and showed good agreement.

Keywords: sandwich walls, interaction diagrams, numerical modeling, eccentricity, reinforced concrete

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Authors: Lim Pey Huan

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Yi-Kuan-Tao has been developing in Malaysia for nearly 60 years. It was initially introduced from mainland China and later from Taiwan starting from the 1970s. Yi-Kuan-Tao was considered a 'new religion' for the local Chinese community in Malaysia in its early stages, as Chinese immigrants primarily practiced Taoism, Buddhism, Christianity, or Catholicism upon settling in the region. The overseas propagation and development of Yi-Kuan-Tao today primarily occur through Taiwanese temples, which began spreading abroad as early as 1949. Particularly since the 1970s, with the rapid economic growth of Taiwan, various branches of Taiwanese Yi-Kuan-Tao have gained economic strength to propagate abroad, further expanding the influence of Yi-Kuan-Tao overseas. Southeast Asia is the region out from Taiwan where the propagation and development of Yi-Kuan-Tao are fastest and most concentrated. With approximately over 6 million Chinese inhabitants, Malaysia's pursuit of traditional Chinese culture has led to a flourishing interest in Yi-Kuan-Tao, particularly its advocacy of the unity of Confucianism, Buddhism, and Taoism, with an emphasis on promoting Confucian thought. Moreover, Taiwan's rapid economic development since the 1970s has enabled Yi-Kuan-Tao to allocate significant human and financial resources for external propagation efforts. Additionally, Malaysia's government has adopted a relatively tolerant policy towards religion since that time, further fostering the flourishing development of Yi-Kuan-Tao in Malaysia. Furthermore, this thesis aims to strengthen the lineage and continuity of the Yi-Kuan-Tao tradition, particularly the branch of Fa Yi Chong De, through the perspective of Heavenly Mandate (天命). By examining the different origins and ethnic backgrounds, it investigates how the Malaysian Chinese community has experienced different changes through the cultural baptism of religion, thus delving into the religious influence of Yi-Kuan-Tao. Given that the Fa Yi Chong De Academy in Taiwan is currently in an active development and construction phase, academic works related to Yi-Kuan-Tao will lay a more solid academic foundation for the future establishment of the academy.

Keywords: initial exploration, cultural shifts, Yi-Kuan-Tao, Malaysian Chinese community

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Authors: Ákos Tótin

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In crop production the most modern hybrids are available for us, therefore the yield and yield stability is determined by the agro-technology. The purpose of the experiment is to adapt the modern agrotechnology to the new type of hybrids. The long-term experiment was set up in 2015-2016 on chernozem soil in the Hajdúság (eastern Hungary). The plots were set up in 75 thousand ha-1 plant density. We examined some mainly use hybrids of Hungary. The conducted studies are: germination dynamic, growing dynamic and the effect of annual weather for the yield. We use three different sowing date as early, average and late, and measure how many plant germinated during the germination process. In the experiment, we observed the germination dynamics in 6 hybrid in 4 replication. In each replication, we counted the germinated plants in 2m long 2 row wide area. Data will be shown in the average of the 6 hybrid and 4 replication. Growing dynamics were measured from the 10cm (4-6 leaf) plant highness. We measured 10 plants’ height in two weeks replication. The yield was measured buy a special plot harvester - the Sampo Rosenlew 2010 – what measured the weight of the harvested plot and also took a sample from it. We determined the water content of the samples for the water release dynamics. After it, we calculated the yield (t/ha) of each plot at 14% of moisture content to compare them. We evaluated the data using Microsoft Excel 2015. The annual weather in each crop year define the maize germination dynamics because the amount of heat is determinative for the plants. In cooler crop year the weather is prolonged the germination. At the 2015 crop year the weather was cold in the beginning what prolonged the first sowing germination. But the second and third sowing germinated faster. In the 2016 crop year the weather was much favorable for plants so the first sowing germinated faster than in the previous year. After it the weather cooled down, therefore the second and third sowing germinated slower than the last year. The statistical data analysis program determined that there is a significant difference between the early and late sowing date growing dynamics. In 2015 the first sowing date had the highest amount of yield. The second biggest yield was in the average sowing time. The late sowing date has lowest amount of yield.

Keywords: germination, maize, sowing date, yield

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Authors: Masami Usui

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After 9/11, the American literary scene was confronted with new perspectives that enabled both writers and readers to recognize the hidden aspects of their political, economic, legal, social, and cultural phenomena. There appeared an argument over new and challenging multicultural aspects after 9/11 and this argument is presented by a tension of space related to 9/11. In Amy Waldman’s the Submission (2011), designing both the memorial park and the family network has a significant meaning in establishing the progress of understanding from multiple perspectives. The most intriguing and controversial topic of racism is reflected in the Submission, where one young architect’s blind entry to the competition for the memorial of Ground Zero is nominated, yet he is confronted with strong objections and hostility as soon as he turns out to be a Muslim named Mohammad Khan. This ‘Khan’ issue, immediately enlarged into a social controversial issue on American soil, causes repeated acts of hostility to Muslim women by ignorant citizens all over America. His idea of the park is to design a new concept of tracing the cultural background of the open space. Against his will, his name is identified as the ‘ingredient’ of the networking of the resistant community with his supporters: on the other hand, the post 9/11 hysteria and victimization is presented in such family associations as the Angry Family Members and Grieving Family Members. These rapidly expanding networks, whether political or not, constructed by the internet, embody the contemporary societal connection and representation. The contemporary quest for the significance of human relationships is recognized as a quest for global peace. Designing both the memorial park and the communication networks strengthens a process of facing the shared conflicts and healing the survivors’ trauma. The tension between the idea and networking of the Garden for the memorial site and the collapse of Ground Zero signifies the double mission of the site: to establish the space to ease the wounded and to remember the catastrophe. Reading the design of these icons of 9/11 in the Submission means that decoding the myth of globalization and its representations in this century.

Keywords: American literature, cultural studies, globalization, literature of catastrophe

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Authors: Ali Göksenli, Barlas Eryürek

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In this study, failure analysis of pipe system at a micro hydroelectric power plant is investigated. Failure occurred at the pipe system in the powerhouse during shut down operation of the water flow by a valve. This locking had caused a sudden shock wave, also called “Water-hammer effect”, resulting in noise and inside pressure increase. After visual investigation of the effect of the shock wave on the system, a circumference crack was observed at the pipe flange weld region. To establish the reason for crack formation, calculations of pressure and stress values at pipe, flange and welding seams were carried out and concluded that safety factor was high (2.2), indicating that no faulty design existed. By further analysis, pipe system and hydroelectric power plant was examined. After observations it is determined that the plant did not include a ventilation nozzle (air trap), that prevents the system of sudden pressure increase inside the pipes which is caused by water-hammer effect. Analyses were carried out to identify the influence of water-hammer effect on inside pressure increase and it was concluded that, according Jowkowsky’s equation, shut down time is effective on inside pressure increase. The valve closing time was uncertain but by a shut down time of even one minute, inside pressure would increase by 7.6 bar (working pressure was 34.6 bar). Detailed investigations were also carried out on the assembly of the pipe-flange system by considering technical drawings. It was concluded that the pipe-flange system was not installed according to the instructions. Two of five weld seams were not applied and one weld was carried out faulty. This incorrect and inadequate weld seams resulted in; insufficient connection of the pipe to the flange constituting a strong notch effect at weld seam regions, increase in stress values and the decrease of strength and safety factor

Keywords: failure analysis, hydroelectric plant, crack, shock wave, welding seam

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Authors: Muhammad Abid

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The ultimate goal of this research was to produce a cold galvanizing compound (CGC) at reduced pigment volume concentration (PVC) to protect metallic structures from corrosion. The influence of the partial replacement of Zn dust by nano-layered graphene (NGr) and Zn metal nanoparticles on the electrochemical, morphological, rheological, and mechanical properties of CGC was investigated. EIS was used to explore the electrochemical nature of coatings. The EIS results revealed that the partial replacement of Zn by NGr and Zn nanoparticles enhanced the cathodic protection at reduced PVC (4:1) by improving the electrical contact between the Zn particles and the metal substrate. The Tafel scan was conducted to support the cathodic behaviour of the coatings. The sample formulated solely with Zn at PVC 4:1 was found to be dominated in physical barrier characteristics over cathodic protection. By increasing the concentration of NGr in the formulation, the corrosion potential shifted towards a more negative side. The coating with 1.5% NGr showed the highest galvanic action at reduced PVC. FE-SEM confirmed the interconnected network of conducting particles. The coating without NGr and Zn nanoparticles at PVC 4:1 showed significant gaps between the Zn dust particles. The novelty was evidenced when micrographs showed the consistent distribution of NGr and Zn nanoparticles all over the surface, which acted as a bridge between spherical Zn particles and provided cathodic protection at a reduced PVC. The layered structure of graphene also improved the physical shielding effect of the coatings, which limited the diffusion of electrolytes and corrosion products (oxides/hydroxides) into the coatings, which was reflected by the salt spray test. The rheological properties of coatings showed good liquid/fluid properties. All the coatings showed excellent adhesion but had different strength values. A real-time scratch resistance assessment showed all the coatings had good scratch resistance.

Keywords: protective coatings, anti-corrosion, galvanization, graphene, nanomaterials, polymers

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Authors: Siti Napsiyah, Ismet Firdaus, Lisma Dyawati Fuaida, Ellies Sukmawati

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This paper examines the existence, role, and challenge of Family Service Agency, in Bahasa Indonesia known as Lembaga Konsultasi Kesejahteraan Keluarga (LK3) of Syarif Hidayatullah State Islamic University (UIN) Jakarta. It has been established since 2012. It is an official agency under the Ministry of Social Affairs of Indonesia. The establishment of LK3 aims to provide psychosocial services for families of students who has psychosocial problem in their life. The study also aims to explore the trend of psychosocial problems of its client (student) for the past three years (2014-2016). The research method of the study is using a qualitative social work research method. A review of selected data of the client of LK3 UIN Syarif Hidayatullah Jakarta around five main issues: Family background, psychosocial mapping, potential resources, student coping mechanism strategy, client strength and network. The study also uses a review of academic performance report as well as an interview and observation. The findings show that the trend of psychosocial problems of the client of LK3 UIN Syarif Hidayatullah Jakarta vary as follow: bad academic performance, low income family, broken home, domestic violence, disability, mental disorder, sexual abuse, and the like. LK3 UIN Syarif Hidayatullah Jakarta has significant roles to provide psychosocial support and services for the survival of the students to deal with their psychosocial problems. Social worker of LK3 performs indigenous social work practice: individual counseling, family counseling, group therapy, home visit, case conference, Islamic Spiritual Approach, and Spiritual Emotional Freedom Technique (SEPT).

Keywords: psychosocial, indigenizing social work, resiliency, coping mechanism

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Authors: Simmi Chopra

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In the last few years, there has been a surge of Autoimmune diseases that have become more like an epidemic all over the world. The reasons vary from stress, insufficient sleep, smoking, genetics, environmental pollution, adulterated foods, and a diet full of “the deadly white,” which is white sugar and white flour. Most of the people diagnosed with these diseases are given steroids, opioids, supplements, or elimination diets to manage their lives, but most of them continue suffering to varying degrees. On the other hand, Ayurveda can help manage autoimmune problems effectively. Ayurveda is a 5000 years old holistic medical system from India that has an individualistic approach where health problems are looked at from the lens of balancing body and mind and by targeting the root cause of the problem. A combination of diet and lifestyle according to Ayurvedic principles, Ayurvedic herbal formulations and Ayurvedic therapies can help in the management of autoimmune and other chronic diseases. Panchkarma, which is an intense six weeks detox method, helps balance our body and mind, and has been very effective in managing autoimmune problems. The paper will introduce the basic concepts of Ayurveda and describe the terminologies- doshas, agni and ama. The paper will discuss the importance of diet and lifestyle according to the individual’s imbalance in the three functional parameters - doshas, which govern every aspect of our body and mind, our cells and tissues. The significance of agni, which can be correlated to digestive strength and ama, which can be correlated to toxins that are formed in our body leading to health problems, will be outlined. The Ayurvedic pathophysiology of autoimmune diseases will be discussed with emphasis on Rheumatoid arthritis, Multiple sclerosis and Psoriasis. Ayurvedic management will be discussed for these autoimmune conditions. As Ayurveda is an individualistic system, one protocol will not work for everyone. Therefore, case studies with Ayurvedic protocols for the above autoimmune disease will be presented. Conclusion: Ayurveda can help in managing as well as arresting the progression of autoimmune problems. Ayurveda is an ancient medical system, is much more needed today than ever. It is a tried and tested holistic system which has been practiced for the past many generations in India.

Keywords: ayurveda, autoimmune, diseases, nutrition

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Authors: Natasha Botha, Gary Corderely, Helen M. Inglis

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With the move to cleaner energy applications the transport industry is working towards on-board hydrogen, or compressed natural gas-fuelled vehicles. A popular method for storage is to use composite overwrapped pressure vessels (COPV) because of their high strength to weight ratios. The proper design of these COPVs are according to international standards; this study aims to provide a preliminary design for a 350 Bar Type IV COPV (i.e. a polymer liner with a composite overwrap). Netting analysis, a popular analytical approach, is used as a first step to generate an initial design concept for the composite winding. This design is further improved upon by following the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel standards, Section X: Fibre-reinforced composite pressure vessels. A design program based on these two approaches is developed using Python. A numerical model of a burst test simulation is developed based on the two approaches and compared. The results indicate that the netting analysis provides a good preliminary design, while the ASME-based design is more robust and accurate as it includes a better approximation of the material behaviour. Netting analysis is an easy method to follow when considering an initial concept design for the composite winding when not all the material characteristics are known. Once these characteristics have been fully defined with experimental testing, an ASME-based design should always be followed to ensure that all designs conform to international standards and practices. Future work entails more detailed numerical testing of the design for improvement, this will include the boss design. Once finalised prototype manufacturing and experimental testing will be conducted, and the results used to improve on the COPV design.

Keywords: composite overwrapped pressure vessel, netting analysis, design, American Society of Mechanical Engineers section x, fiber-reinforced, hydrogen storage

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Authors: Camilla Elphick, Graham Hole, Samuel Hutton, Graham Pike

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Pupil size has been found to change irrespective of luminosity, suggesting that it can be used to make inferences about cognitive processes, such as cognitive load. To see whether identifying a target requires a different cognitive load to rejecting distractors, the effect of viewing a target (compared with viewing distractors) on pupil size was investigated using a sequential video lineup procedure with two lineup sessions. Forty one participants were chosen randomly via the university. Pupil sizes were recorded when viewing pre target distractors and post target distractors and compared to pupil size when viewing the target. Overall, pupil size was significantly larger when viewing the target compared with viewing distractors. In the first session, pupil size changes were significantly different between participants who identified the target (Hits) and those who did not. Specifically, the pupil size of Hits reduced significantly after viewing the target (by 26%), suggesting that cognitive load reduced following identification. The pupil sizes of Misses (who made no identification) and False Alarms (who misidentified a distractor) did not reduce, suggesting that the cognitive load remained high in participants who failed to make the correct identification. In the second session, pupil sizes were smaller overall, suggesting that cognitive load was smaller in this session, and there was no significant difference between Hits, Misses and False Alarms. Furthermore, while the frequency of Hits increased, so did False Alarms. These two findings suggest that the benefits of including a second session remain uncertain, as the second session neither provided greater accuracy nor a reliable way to measure it. It is concluded that pupil size is a measure of face recognition strength in the first session of a target present lineup procedure. However, it is still not known whether cognitive load is an adequate explanation for this, or whether cognitive engagement might describe the effect more appropriately. If cognitive load and cognitive engagement can be teased apart with further investigation, this would have positive implications for understanding eyewitness identification. Nevertheless, this research has the potential to provide a tool for improving the reliability of lineup procedures.

Keywords: cognitive load, eyewitness identification, face recognition, pupillometry

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Authors: Noura El-Ahmady El-Naggar

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L-asparaginase is an important enzyme as therapeutic agents used in combination therapy with other drugs in the treatment of acute lymphoblastic leukemia in children. L-asparaginase producing actinomycete strain, NEAE-K, was isolated from soil sample and identified on the basis of morphological, cultural, physiological and biochemical properties, together with 16S rDNA sequence as new subsp. Streptomyces rochei subsp. chromatogenes NEAE-K and sequencing product (1532 bp) was deposited in the GenBank database under accession number KJ200343. The study was conducted to screen parameters affecting the production of L-asparaginase by Streptomyces rochei subsp. chromatogenes NEAE-K on solid state fermentation using Plackett–Burman experimental design. Sixteen different independent variables including incubation time, moisture content, inoculum size, temperature, pH, soybean meal+ wheat bran, dextrose, fructose, L-asparagine, yeast extract, KNO3, K2HPO4, MgSO4.7H2O, NaCl, FeSO4. 7H2O, CaCl2, and three dummy variables were screened in Plackett–Burman experimental design of 20 trials. The most significant independent variables affecting enzyme production (dextrose, L-asparagine and K2HPO4) were further optimized by the central composite design. As a result, a medium of the following formula is the optimum for producing an extracellular L-asparaginase by Streptomyces rochei subsp. chromatogenes NEAE-K from solid state fermentation: g/L (soybean meal+ wheat bran 15, dextrose 3, fructose 4, L-asparagine 8, yeast extract 2, KNO3 1, K2HPO4 2, MgSO4.7H2O 0.5, NaCl 0.1, FeSO4. 7H2O 0.02, CaCl2 0.01), incubation time 7 days, moisture content 50%, inoculum size 3 mL, temperature 30°C, pH 8.5.

Keywords: streptomyces rochei subsp. chromatogenes neae-k, 16s rrna, identification, solid state fermentation, l-asparaginase production, plackett-burman design, central composite design

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Authors: Allaw Kamel, Al-Chami Leila

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It is important to reduce the human influence on natural resources by identifying an appropriate land use. Moreover, it is essential to carry out the scientific land evaluation. Such kind of analysis allows identifying the main factors of agricultural production and enables decision makers to develop crop management in order to increase the land capability. The key is to match the type and intensity of land use with its natural capability. Therefore; in order to benefit from these areas and invest them to obtain good agricultural production, they must be organized and managed in full. Lebanon suffers from the unorganized agricultural use. We take south Lebanon as a study area, it is the most fertile ground and has a variety of crops. The study aims to identify and locate the most suitable area to cultivate thirteen type of permanent trees which are: apples, avocados, stone fruits in coastal regions and stone fruits in mountain regions, bananas, citrus, loquats, figs, pistachios, mangoes, olives, pomegranates, and grapes. Several geographical factors are taken as criterion for selection of the best location to cultivate. Soil, rainfall, PH, temperature, and elevation are main inputs to create the final map. Input data of each factor is managed, visualized and analyzed using Geographic Information System (GIS). Management GIS tools are implemented to produce input maps capable of identifying suitable areas related to each index. The combination of the different indices map generates the final output map of the suitable place to get the best permanent tree productivity. The output map is reclassified into three suitability classes: low, moderate, and high suitability. Results show different locations suitable for different kinds of trees. Results also reflect the importance of GIS in helping decision makers finding a most suitable location for every tree to get more productivity and a variety in crops.

Keywords: agricultural production, crop management, geographical factors, Geographic Information System, GIS, land capability, permanent trees, suitable location

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Authors: Reza Eslami-Farsani, Hamed Khosravi, Saba Fayazzadeh

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Lightweight and efficient structures have the aim to enhance the efficiency of the components in various industries. Toward this end, composites are one of the most widely used materials because of durability, high strength and modulus, and low weight. One type of the advanced composites is grid-stiffened composite (GSC) structures which have been extensively considered in aerospace, automotive, and aircraft industries. They are one of the top candidates for replacing some of the traditional components which are used here. Although there are a good number of published surveys on the design aspects and fabrication of GSC structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Matrix modification using nanoparticles is an effective method to enhance the flexural properties of the fibrous composites. In the present study, a silane coupling agent (3-glycidoxypropyltrimethoxysilane/3-GPTS) was introduced onto the silica (SiO2) nanoparticle surface and its effects on the three-point flexural response of isogrid E-glass/epoxy composites were assessed. Based on the fourier transform infrared spectrometer (FTIR) spectra, it was inferred that the 3-GPTS coupling agent was successfully grafted onto the surface of SiO2 nanoparticles after modification. Flexural test revealed an improvement of 16%, 14%, and 36% in stiffness, maximum load and energy absorption of the isogrid specimen filled with 3 wt.% 3-GPTS/SiO2 compared to the neat one. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. Also, 3-GPTMS functionalization had a positive effect on the flexural behavior of the multiscale isogrid composites. In conclusion, this study suggests that the addition of modified silica nanoparticles is a promising method to improve the flexural properties of the grid-stiffened fibrous composite structures.

Keywords: isogrid-stiffened composite panels, silica nanoparticles, surface modification, flexural properties, energy absorption

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Authors: Asif Arshid, Ying Huang, Denver Tolliver

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Finite Element (FE) method coupled with ever-increasing computational powers has substantially advanced the reliability of deterministic three dimensional structural analyses of a structure with uniform material properties. However, railways trackbed is made up of diverse group of materials including steel, wood, rock and soil, while each material has its own varying levels of heterogeneity and imperfections. It is observed that the application of probabilistic methods for trackbed structural analysis while incorporating the material and geometric variabilities is deeply underworked. The authors developed and validated a 3-dimensional FE based numerical trackbed model and in this study, they investigated the influence of variability in Young modulus and thicknesses of granular layers (Ballast and Subgrade) on the reliability index (-index) of the subgrade layer. The influence of these factors is accounted for by changing their Coefficients of Variance (COV) while keeping their means constant. These variations are formulated using Gaussian Normal distribution. Two failure mechanisms in subgrade namely Progressive Shear Failure and Excessive Plastic Deformation are examined. Preliminary results of risk-based probabilistic analysis for Progressive Shear Failure revealed that the variations in Ballast depth are the most influential factor for vertical stress at the top of subgrade surface. Whereas, in case of Excessive Plastic Deformations in subgrade layer, the variations in its own depth and Young modulus proved to be most important while ballast properties remained almost indifferent. For both these failure moods, it is also observed that the reliability index for subgrade failure increases with the increase in COV of ballast depth and subgrade Young modulus. The findings of this work is of particular significance in studying the combined effect of construction imperfections and variations in ground conditions on the structural performance of railroad trackbed and evaluating the associated risk involved. In addition, it also provides an additional tool to supplement the deterministic analysis procedures and decision making for railroad maintenance.

Keywords: finite element analysis, numerical modeling, probabilistic methods, risk and reliability analysis, subgrade

Procedia PDF Downloads 139