Search results for: modified ground structure

Authors: Mercedeh Malekzadeh

Abstract:

Scrap tires are the source of wastes that cause the environmental problems. The major components of these tires are rubber and carbon black. These components can be used again for different applications by utilizing physical and chemical processes. Pyrolysis is a way that converts rubber portion of scrap tires to oil and gas and the carbon black recovers to pyrolytic carbon black. This pyrolytic carbon black can be used to reinforce rubber and metal, coating preparation, electronic thermal manager and so on. The porous structure of this carbon black also makes it as a suitable choice for heavy metals removal from water. In this work, the application of base treated pyrolytic carbon black was studied as an adsorbent for chromium (III) removal from water in a batch process. Pyrolytic carbon blacks in two natural and base treated forms were characterized by scanning electron microscopy and energy dispersive analysis x-ray. The effects of adsorbent dosage, contact time, initial concentration of chromium (III) and pH were considered on the adsorption process. The adsorption capacity was 19.76 mg/g. Maximum adsorption was seen after 120 min at pH=3. The equilibrium data were considered and better fitted to Langmuir model. The adsorption kinetic was evaluated and confirmed with the pseudo second order kinetic. Results have shown that the base treated pyrolytic carbon black obtained from scrap tires can be used as a cheap adsorbent for removal of chromium (III) from the water.

Keywords: chromium (III), pyrolytic carbon, scrap tire, water

Procedia PDF Downloads 184

Authors: Hussain Ali Bekhet, Nor Salwati Othman

Abstract:

Malaysia has achieved remarkable economic growth since 1957, moving toward modernization from a predominantly agriculture base to manufacturing and—now—modern services. The development policies (i.e., New Economic Policy [1970–1990], the National Development Policy [1990–2000], and Vision 2020) have been recognized as the most important drivers of this transformation. The transformation of the economic structure has moved along with rapid gross domestic product (GDP) growth, urbanization growth, and greater demand for energy from mainly fossil fuel resources, which in turn, increase CO2 emissions. Malaysia faced a great challenge to bring down the CO2 emissions without compromising economic development. Solid policies and a strategy to reduce dependencies on fossil fuel resources and reduce CO2 emissions are needed in order to achieve sustainable development. This study provides an overview of the Malaysian economic, energy, and environmental situation, and explores the existing policies and strategies related to energy and the environment. The significance is to grasp a clear picture on what types of policies and strategies Malaysia has in hand. In the future, this examination should be extended by drawing a comparison with other developed countries and highlighting several options for sustainable development.

Keywords: energy policies, energy efficiency, renewable energy, green building, Malaysia, sustainable development

Procedia PDF Downloads 227

Authors: Mourad Makhlouf, Bouabdellah Benaicha, Zoubir Benmaamar, Didier Villemin

Abstract:

The addition of combustion catalysts to ammonium perchlorate-based composite fuels can indeed significantly enhance their performance. In this work, a nanocomposite was synthesized using graphene oxide (GO) and hematite nanoparticles grafted onto graphene oxide as a catalyst support.To characterize the nanocomposite, several experimental techniques were employed, including Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). FTIR is useful for analyzing chemical bonding and functional groups, while Raman spectroscopy provides information about the vibrational modes of the materials. SEM allows for visualizing the surface morphology and structure.The thermal analysis of two mixtures, one based on AP/GO and the other on AP/GO-Fe2O3, was conducted with varying percentages. The results indicated that the nanocomposite GO-Fe2O3 acted as a catalyst, significantly accelerating the thermal decomposition process of AP. This catalytic effect ultimately led to an improvement in the energy performance of the composite fuel.Overall, the synthesis and characterization of the nanocomposite, as well as the thermal analysis, demonstrated the effectiveness of GO-Fe2O3 as a combustion catalyst in enhancing the performance of ammonium perchlorate-based composite fuels.

Keywords: composite propellants, ammonium perchlorate, nanocomposite, catalytic support, hematite nanoparticles, graphene oxide, thermal decomposition

Procedia PDF Downloads 20

Authors: Seyedehsomayeh Hosseini

Abstract:

Much attention has been paid over centuries to understanding and solving the problem of minimization of functions. Compared to linear programming and nonlinear unconstrained optimization problems, nonlinear constrained optimization problems are much more difficult. Since the procedure of finding an optimizer is a search based on the local information of the constraints and the objective function, it is very important to develop techniques using geometric properties of the constraints and the objective function. In fact, differential geometry provides a powerful tool to characterize and analyze these geometric properties. Thus, there is clearly a link between the techniques of optimization on manifolds and standard constrained optimization approaches. Furthermore, there are manifolds that are not defined as constrained sets in R^n an important example is the Grassmann manifolds. Hence, to solve optimization problems on these spaces, intrinsic methods are used. In a nondifferentiable problem, the gradient information of the objective function generally cannot be used to determine the direction in which the function is decreasing. Therefore, techniques of nonsmooth analysis are needed to deal with such a problem. As a manifold, in general, does not have a linear structure, the usual techniques, which are often used in nonsmooth analysis on linear spaces, cannot be applied and new techniques need to be developed. This paper presents necessary and sufficient conditions for a strict local minimum of extended real-valued, nonsmooth functions defined on Riemannian manifolds.

Keywords: Riemannian manifolds, nonsmooth optimization, lower semicontinuous functions, subdifferential

Procedia PDF Downloads 349

Authors: Ahmed O. Babaleye, Rafet E. Kurt

Abstract:

The global oil and gas industry is beginning to witness an increase in the number of installations moving towards decommissioning. Decommissioning of offshore installations is a complex, costly and hazardous activity, making safety one of the major concerns. Among existing removal options, complete and partial removal options pose the highest risks. Therefore, a dynamic risk model of the accidents from the two options is important to assess the risks on an overall basis. In this study, a risk-based safety model is developed to conduct quantitative risk analysis (QRA) for jacket structure systems failure. Firstly, bow-tie (BT) technique is utilised to model the causal relationship between the system failure and potential accident scenarios. Subsequently, to relax the shortcomings of BT, Bayesian Belief Networks (BBNs) were established to dynamically assess associated uncertainties and conditional dependencies. The BBN is developed through a similitude mapping of the developed bow-tie. The BBN is used to update the failure probabilities of the contributing elements through diagnostic analysis, thus, providing a case-specific and realistic safety analysis method when compared to a bow-tie. This paper presents the application of dynamic safety analysis to guide the allocation of risk control measures and consequently, drive down the avoidable cost of remediation.

Keywords: Bayesian belief network, offshore decommissioning, dynamic safety model, quantitative risk analysis

Procedia PDF Downloads 266

Authors: Amal Mohammed Alqahatni

Abstract:

This paper is a non-empirical analysis of existing literature on digital leadership competency, data-driven organizations, and dealing with AI technology (big data). This paper will provide insights into the importance of developing the leader’s analytical skills and style to be more effective for high-quality decision-making in a data-driven organization and achieve creativity during the organization's transformation to be digitalized. Despite the enormous potential that big data has, there are not enough experts in the field. Many organizations faced an issue with leadership style, which was considered an obstacle to organizational improvement. It investigates the obstacles to leadership style in this context and the challenges leaders face in coaching and development. The leader's lack of analytical skill with AI technology, such as big data tools, was noticed, as was the lack of understanding of the value of that data, resulting in poor communication with others, especially in meetings when the decision should be made. By acknowledging the different dynamics of work competency and organizational structure and culture, organizations can make the necessary adjustments to best support their leaders. This paper reviews prior research studies and applies what is known to assist with current obstacles. This paper addresses how analytical leadership will assist in overcoming challenges in a data-driven organization's work environment.

Keywords: digital leadership, big data, leadership style, digital leadership challenge

Procedia PDF Downloads 52

Authors: Ismene Ithai Bras-Ruiz

Abstract:

Learning Analytics (LA) is employed by universities not only as a tool but as a specialized ground to enhance students and professors. However, not all the academic programs apply LA with the same goal and use the same tools. In fact, LA is formed by five main fields of study (academic analytics, action research, educational data mining, recommender systems, and personalized systems). These fields can help not just to inform academic authorities about the situation of the program, but also can detect risk students, professors with needs, or general problems. The highest level applies Artificial Intelligence techniques to support learning practices. LA has adopted different techniques: statistics, ethnography, data visualization, machine learning, natural language process, and data mining. Is expected that any academic program decided what field wants to utilize on the basis of his academic interest but also his capacities related to professors, administrators, systems, logistics, data analyst, and the academic goals. The Open and Distance University System (SUAYED in Spanish) of the University National Autonomous of Mexico (UNAM), has been working for forty years as an alternative to traditional programs; one of their main supports has been the employ of new information and communications technologies (ICT). Today, UNAM has one of the largest network higher education programs, twenty-six academic programs in different faculties. This situation means that every faculty works with heterogeneous populations and academic problems. In this sense, every program has developed its own Learning Analytic techniques to improve academic issues. In this context, an investigation was carried out to know the situation of the application of LA in all the academic programs in the different faculties. The premise of the study it was that not all the faculties have utilized advanced LA techniques and it is probable that they do not know what field of study is closer to their program goals. In consequence, not all the programs know about LA but, this does not mean they do not work with LA in a veiled or, less clear sense. It is very important to know the grade of knowledge about LA for two reasons: 1) This allows to appreciate the work of the administration to improve the quality of the teaching and, 2) if it is possible to improve others LA techniques. For this purpose, it was designed three instruments to determinate the experience and knowledge in LA. These were applied to ten faculty coordinators and his personnel; thirty members were consulted (academic secretary, systems manager, or data analyst, and coordinator of the program). The final report allowed to understand that almost all the programs work with basic statistics tools and techniques, this helps the administration only to know what is happening inside de academic program, but they are not ready to move up to the next level, this means applying Artificial Intelligence or Recommender Systems to reach a personalized learning system. This situation is not related to the knowledge of LA, but the clarity of the long-term goals.

Keywords: academic improvements, analytical techniques, learning analytics, personnel expertise

Procedia PDF Downloads 115

Authors: Seungwoo Kim, Yeongcheol Cho

Abstract:

In this paper, a holonomic mobile robot is designed in omnidirectional wheels and an adaptive fuzzy controller is presented for its precise trajectories. A kind of adaptive controller based on fuzzy multi-layered algorithm is used to solve the big parametric uncertainty of motor-controlled dynamic system of 3-wheels omnidirectional mobile robot. The system parameters such as a tracking force are so time-varying due to the kinematic structure of omnidirectional wheels. The fuzzy adaptive control method is able to solve the problems of classical adaptive controller and conventional fuzzy adaptive controllers. The basic idea of new adaptive control scheme is that an adaptive controller can be constructed with parallel combination of robust controllers. This new adaptive controller uses a fuzzy multi-layered architecture which has several independent fuzzy controllers in parallel, each with different robust stability area. Out of several independent fuzzy controllers, the most suited one is selected by a system identifier which observes variations in the controlled system parameter. This paper proposes a design procedure which can be carried out mathematically and systematically from the model of a controlled system. Finally, the good performance of a holonomic mobile robot is confirmed through live tests of the tracking control task.

Keywords: fuzzy adaptive control, fuzzy multi-layered controller, holonomic mobile robot, omnidirectional wheels, robustness and stability.

Procedia PDF Downloads 340

Authors: Showkat Ahmad Bhat, Iqra Reyaz, Falaque ul Afshan, Ahmad Arif Reshi, Muneeb U. Rehman, Manzoor R. Mir, Sabhiya Majid, Sonallah, Sheikh Bilal, Ishraq Hussain

Abstract:

Background: Gastric cancer is the fourth most common cancer and the second leading cause of worldwide cancer-related deaths, with a wide variation in incidence rates across different geographical areas. The current view of cancer is that a malignancy arises from a transformation of the genetic material of a normal cell, followed by successive mutations and by chain of alterations in genes such as DNA repair genes, oncogenes, Tumor suppressor genes. Minerals are necessary for the functioning of several transcriptional factors, proteins that recognize certain DNA sequences and have been found to play a role in gastric cancer. Material Methods:The present work was a case control study and its aim was to ascertain the role of minerals and promoter hypermethylation of CpG islands of DAP-K gene in Gastric cancer patients among the Kashmiri population. Serum was extracted from all the samples and mineral estimation was done by AAS from serum, DNA was also extracted and was modified using bisulphite modification kit. Methylation-specific PCR was used for the analysis of the promoter hypermethylation status of DAP-K gene. The epigenetic analysis revealed that unlike other high risk regions, Kashmiri population has a different promoter hypermethylation profile of DAP-K gene and has different mineral profile. Results: In our study mean serum copper levels were significantly different for the two genders (p<0.05), while as no significant differences were observed for iron and zinc levels. In Methylation-specific PCR the methylation status of the promoter region of DAP-K gene was as 67.50% (27/40) of the gastric cancer tissues showed methylated DAP-K promoter and 32.50% (13/40) of the cases however showed unmethylated DAP-K promoter. Almost all 85% (17/20) of the histopathologically confirmed normal tissues showed unmethylated DAP-K promoter except only in 3 cases where DAP-K promoter was found to be methylated. The association of promoter hypermethylation with gastric cancer was evaluated by χ2 (Chi square) test and was found to be significant (P=0.0006). Occurrence of DAP-K methylation was found to be unequally distributed in males and females with more frequency in males than in females but the difference was not statistically significant (P =0.7635, Odds ratio=1.368 and 95% C.I=0.4197 to 4.456). When the frequency of DAP-K promoter methylation was compared with clinical staging of the disease, DAP-K promoter methylation was found to be certainly higher in Stage III/IV (85.71%) compared to Stage I/ II (57.69%) but the difference was not statistically significant (P =0.0673). These results suggest that DAP-K aberrant promoter hypermethylation in Kashmiri population contributes to the process of carcinogenesis in Gastric cancer and is reportedly one of the commonest epigenetic changes in the development of Gastric cancer.

Keywords: gastric cancer, minerals, AAS, hypermethylation, CpG islands, DAP-K gene

Procedia PDF Downloads 504

Authors: Anna Siegler, Sara Bigazzi, Sara Serdult, Ildiko Bokretas

Abstract:

Social identity emerging from group membership defines the representational processes of our social reality. Based on our theoretical assumption the subjective perception of identity threat leads to an instable identity structure. The need to re-establish the positive identity will lead us to strengthen group boundaries. Prejudice in our perspective offer psychological security those who thinking in exclusive barriers, and we suggest that those who identify highly with their ingroup/national identity and less with superordinate identities take distance from others and this is related to their perception of threat. In our study we used a newly developed questionnaire, the Multiple Threat and Prejudice Questionnaire (MTPQ) which measure identity threat at different dimensions of identification (national, existential, gender, religious) and the distancing of different outgroups, over and above we worked with Social Dominance Orientation (SDO) and Identification with All Humanity Scale (IWAH). We conduct one data collection (N=1482) in a Hungarian sample to examine the connection between national threat and distance-taking, and this survey includes the investigation (N=218) of identification with different group categories. Our findings confirmed that those who feel themselves threatened in their national identity aspects are less likely to identify themselves with superordinate groups and this correlation is much stronger when they think about the nation as a bio-cultural unit, while if nation defined as a social-economy entity this connection is less powerful and has just the opposite direction.

Keywords: group boundaries, identity threat, prejudice, superordinate groups

Procedia PDF Downloads 389

Authors: Kazui Sasakii, Seira Mormune-Moriya, Hiroaki Tanahashi, Shigeji Kongaya

Abstract:

Poly (3.4-ethylenedioxythiophene) doped with poly (4-styrene sulfonate) (PEDOT: PSS) attracted a great deal of attention because of its unique characteristics of flexibility, optical properties, heat resistance and colloidal dispersion in water. It is well known that when high boiling solvents such as ethylene glycol or dimethyl sulfoxide are added as a secondary dopant to the micellar structure, PEDOT microcrystallizes and becomes highly conductive. In previous study bis(4-hydroxyphenyl) sulfone (BPS) was used as a secondary dopant for PEDOT:PSS and the enhancement of the conductivity was revealed. However, ductility is one of the serious issues which limited the application of PEDOT:PSS/BPS. So far, the composition with polymer binders has been conducted, however, polymer binders decrease the conductivity of the materials. In this study, PEDOT: PSS composites with polyester (PEs) were prepared by a simple aqueous process using PEs emulsion. The structural studies revealed that PEDOT:PSS and PEs were homogeneously distributed in the composites. It was found that the properties of PEDOT:PSS were remarkably enhanced by the incorporation of PEs. According to the tensile test, the ductility of PEDOT:PSS was remarkably improved. Interestingly, the conductivity of PEDOT:PSS/PEs composites was higher than that of neat PEDOT:PSS. For example, the conductivity increased by 8% at PEs content of 25 wt%. Since PEDOT:PSS were homogeneously dispersed on the surface of PEs particles, it was assumed that the conductive pathway was constructed by PEs particles in the nanocomposites. Therefore, a significant increase in conductivity was achieved.

Keywords: polymer composites, conductivity, PEDOT:PSS, polyester

Procedia PDF Downloads 101

Authors: Ahmad Sharif Ahmadi, Yoshitaka Kajita

Abstract:

With massive population expansion and fast economic development in last decade, urban land has increasingly expanded and formed high informal development territory in Kabul city. This paper investigates integrated urbanization trends in Kabul city since the formation of the basic structure of the present city using GIS and remote sensing. This study explores the spatial and temporal difference of urban land expansion and land use categories among different time intervals, 1964-1978 and 1978-2008 from 1964 to 2008 in Kabul city. Furthermore, the goal of this paper is to understand the extent of urban land expansion and the factors driving urban land expansion in Kabul city. Many factors like population expansion, the return of refugees from neighboring countries and significant economic growth of the city affected urban land expansion. Across all the study area urban land expansion rate, population expansion rate and economic growth rate have been compared to analyze the relationship of driving forces with urban land expansion. Based on urban land change data detected by interpreting land use maps, it was found that in the entire study area the urban territory has been expanded by 14 times between 1964 and 2008.

Keywords: GIS, Kabul city, land use, urban land expansion, urbanization

Procedia PDF Downloads 319

Authors: Bunty Tomar, Shiva S.

Abstract:

Fabrication of steel and copper-based functionally graded material (FGM) through cold metal transfer-based wire arc additive manufacturing is a novel exploration. Components combining Cu and steel show significant usage in many industrial applications as they combine high corrosion resistance, ductility, thermal conductivity, and wear resistance to excellent mechanical properties. Joining steel and copper is challenging due to the mismatch in their thermo-mechanical properties. In this experiment, a functionally graded material (FGM) structure of pure copper (Cu) and 316L stainless steel (SS) was successfully developed using cold metal transfer-based wire arc additive manufacturing (CMT-WAAM). The interface of the fabricated samples was characterized under optical microscopy, field emission scanning electron microscopy, and X-ray diffraction techniques. Detailed EBSD and TEM analysis was performed to analyze the grain orientation, strain distribution, grain boundary misorientations, and formation of metastable and intermetallic phases. Mechanical characteristics of deposits was also analyzed using tensile and wear testing. This works paves the way to use CMT-WAAM to fabricate steel/copper FGMs.

Keywords: wire arc additive manufacturing (waam), cold metal transfer (cmt), metals and alloys, mechanical properties, characterization

Procedia PDF Downloads 64

Authors: Irene Capecchi, Tommaso Borghini, Iacopo Bernetti

Abstract:

One of the most common pieces of equipment still used today for pruning, felling, and processing trees is the chainsaw in forestry. However, chainsaw use highlights dangers and one of the highest rates of accidents in both professional and non-professional work. Felling is proportionally the most dangerous phase, both in severity and frequency, because of the risk of being hit by the plant the operator wants to cut down. To avoid this, a correct sequence of chainsaw cuts must be taught concerning the different conditions of the tree. Virtual reality (VR) makes it possible to virtually simulate chainsaw use without danger of injury. The limitations of the existing applications are as follow. The existing platforms are not symmetrical collaborative because the trainee is only in virtual reality, and the trainer can only see the virtual environment on a laptop or PC, and this results in an inefficient teacher-learner relationship. Therefore, most applications only involve the use of a virtual chainsaw, and the trainee thus cannot feel the real weight and inertia of a real chainsaw. Finally, existing applications simulate only a few cases of tree felling. The objectives of this research were to implement and test a symmetrical collaborative training application based on VR and mixed reality (MR) with the overlap between real and virtual chainsaws in MR. The research and training platform was developed for the Meta quest 2 head-mounted display. The research and training platform application is based on the Unity 3D engine, and Present Platform Interaction SDK (PPI-SDK) developed by Meta. PPI-SDK avoids the use of controllers and enables hand tracking and MR. With the combination of these two technologies, it was possible to overlay a virtual chainsaw with a real chainsaw in MR and synchronize their movements in VR. This ensures that the user feels the weight of the actual chainsaw, tightens the muscles, and performs the appropriate movements during the test allowing the user to learn the correct body posture. The chainsaw works only if the right sequence of cuts is made to felling the tree. Contact detection is done by Unity's physics system, which allows the interaction of objects that simulate real-world behavior. Each cut of the chainsaw is defined by a so-called collider, and the felling of the tree can only occur if the colliders are activated in the right order simulating a safe technique felling. In this way, the user can learn how to use the chainsaw safely. The system is also multiplayer, so the student and the instructor can experience VR together in a symmetrical and collaborative way. The platform simulates the following tree-felling situations with safe techniques: cutting the tree tilted forward, cutting the medium-sized tree tilted backward, cutting the large tree tilted backward, sectioning the trunk on the ground, and cutting branches. The application is being evaluated on a sample of university students through a special questionnaire. The results are expected to test both the increase in learning compared to a theoretical lecture and the immersive and telepresence of the platform.

Keywords: chainsaw, collaborative symmetric virtual reality, mixed reality, operator training

Procedia PDF Downloads 93

Authors: Kinjal Trivedi, Ramesh V. Upadhyay

Abstract:

Magnetic fluid as a nanolubricant is a most recent field of study due to its unusual properties that can be tuned by applying a magnetic field. In present work, four ball tester has been used to investigate the tribological properties of the magnetic fluid having a 4 wt% of nanoparticles. The structural characterization of fluid shows crystallite size of particle is 11.7 nm and particles are nearly spherical in nature. The magnetic characterization shows the fluid saturation magnetization is 2.2 kA/m. The magnetic field applied using permanent strip magnet (0 to 1.6 mT) on the faces of the lock nut and fixing a solenoid (0 to 50 mT) around a shaft, such that shaft rotates freely. The magnetic flux line for both the systems analyzed using finite elemental analysis. The coefficient of friction increases with the application of magnetic field using permanent strip magnet compared to zero field value. While for the solenoid, it decreases at 20 mT. The wear scar diameter is lower for 1.1 mT and 20 mT when the magnetic field applied using permanent strip magnet and solenoid, respectively. The coefficient of friction and wear scar reduced by 29 % and 7 % at 20 mT using solenoid. The worn surface analysis carried out using Scanning Electron Microscope and Atomic Force Microscope to understand the wear mechanism. The results are explained on the basis of structure formation in a magnetic fluid upon application of magnetic field. It is concluded that the tribological properties of magnetic fluid depend on magnetic field and its applied direction.

Keywords: four ball tester, magnetic fluid, nanolubricant, tribology

Procedia PDF Downloads 220

Authors: Clarinda V. Nhangumbe, Ercília Sousa

Abstract:

Weather Derivatives are financial instruments used to cover non-catastrophic weather events and can be expressed in the form of standard or plain vanilla products, structured or exotics products. The underlying asset, in this case, is the weather index, such as temperature, rainfall, humidity, wind, and snowfall. The complexity of the Weather Derivatives structure shows the weakness of the Black Scholes framework. Therefore, under the risk-neutral probability measure, the option price of a weather contract can be given as a unique solution of a two-dimensional partial differential equation (parabolic in one direction and hyperbolic in other directions), with an initial condition and subjected to adequate boundary conditions. To calculate the price of the option, one can use numerical methods such as the Monte Carlo simulations and implicit finite difference schemes conjugated with Semi-Lagrangian methods. This paper is proposed two explicit methods, namely, first-order upwind in the hyperbolic direction combined with Lax-Wendroff in the parabolic direction and first-order upwind in the hyperbolic direction combined with second-order upwind in the parabolic direction. One of the advantages of these methods is the fact that they take into consideration the boundary conditions obtained from the financial interpretation and deal efficiently with the different choices of the convection coefficients.

Keywords: incomplete markets, numerical methods, partial differential equations, stochastic process, weather derivatives

Procedia PDF Downloads 75

Authors: Elaosi Vhurumuku

Abstract:

During the past twenty years, there has been an increased interest by science educators in researching and developing teachers’ pedagogical content knowledge for teaching the nature of science (PCKNOS). While there has been this surge in interest in the idea of PCKNOS, there has not been a common understanding among NOS researchers as to how exactly the PCKNOS concept should be construed. In this paper, we analyse and evaluate published accredited journal articles on PCKNOS research. We also draw from our teaching experiences. The major points of foci are the researchers’ presentations of SMKNOS and their centres of attention regarding the elements of PCKNOS. Our content, cluster analysis, and evaluation of the studies on PCKNOS reveal that most researchers have presented SMKNOS in the form of a heuristic or a set of heuristics (targeted NOS ideas) to be mastered by teachers or learners. Furthermore, we found that most of the researchers’ attention has been on developing and recommending teacher pedagogical practices for teaching NOS. From this, we synthesize and propose a subject knowledge content structure and a pedagogical approach that we believe is relevant and appropriate for secondary school and science teacher education if the goal of science education for scientific literacy is to be achieved. The justification of our arguments is rooted in tracing and unpacking the origins and meaning of pedagogical content knowledge (PCK). From our analysis, synthesis, and evaluation, as well as teaching experiences, we distil and construct a meaning for the PCKNOS construct.

Keywords: pedagogical content knowledge, teaching, nature of science, construct, subject matter knowledge

Procedia PDF Downloads 68

Authors: M. Keršič, M. Lužnik, J. Lužnik

Abstract:

Cervical dilatation and membrane herniation before 26th week of gestation poses very high risk for extremely and very premature childbirth. Cerclage with mesh cap (mesh cerclage, MC) can greatly diminish this risk and provide additional positive effects. Between 2005 and 2014, MC has been performed in 9 patients with singleton pregnancies who had prolapsed membranes beyond external cervical/uterine os before 25th week of pregnancy (one in 29th). With patients in general anaesthesia, lithotomy and Trendelenburg position (about 25°) prolapsed membranes were repositioned in the uterine cavity, using tampon soaked in antiseptic solution (Skinsept mucosa). A circular, a type of purse-string suture (main band) with double string Ethilon 1 was applied at about 1 to 1.5 cm from the border of the external uterine os - 6 to 8 stitches were placed, so the whole external uterine os was encircled (modified McDonald). In the next step additional Ethilon 0 sutures were placed around all exposed parts of the main double circular suture and loosely tightened. On those sutures, round tailored (diameter around 6 cm) mesh (Prolene® or Gynemesh* PS) was attached. In all 9 cases, gestation was prolonged on average for 9 weeks and 4 days (67 days). In four cases maturity was achieved. Mesh was removed in 37th–38th week of pregnancy or if spontaneous labour began. In two cases, a caesarean section was performed because of breech presentation. In the first week after birth in 22nd week one new born died because of immaturity (premature birth was threatening in 18th week and then MC was placed). Ten years after first MC, 8 of 9 women with singleton pregnancy and MC performed have 8 healthy children from these pregnancies. Mesh cerclage successfully closed the opened cervical canal or uterine orifice and prevented further membrane herniation and membrane rupture. MC also provides a similar effect as with occluding the external os with suturing but without interrupting the way for excretion of abundant cervical mucus. The mesh also pulls the main circular band outwards and thus lowers the chance of suture cutting through the remaining cervix. MC prolonged gestation very successfully (mean for 9 weeks and 4 days) and thus increased possibility for survival and diminished the risk for complications in very early preterm delivered survivors in cases with cervical dilatation and membrane herniation before 26th week of gestation. Without action possibility to achieve at least 28th or 32nd week of gestation would be poor.

Keywords: cervical insufficiency, mesh cerclage, membrane protrusion, premature birth prevention, physical exam-indicated cerclage, rescue cerclage

Procedia PDF Downloads 177

Authors: S. A. Anuar, N. H. Hamid, M. H. Hashim, S. M. D. Salleh

Abstract:

This paper present the experimental work on the seismic performance of double unit tunnel form building (TFB) subjected to in-plane lateral cyclic loading. A one third scale of 3-storey double unit of TFB is tested at ±0.01%, ±0.1%, ±0.25%, ±0.5%, ±0.75% and ±1.0% drifts until the structure achieves its strength degradation. After that, the TFB is repaired and retrofitted using additional shear wall, steel angle and CFRP sheet. A similar testing approach is applied to the specimen after repair and retrofit. The crack patterns, lateral strength, stiffness, ductility and equivalent viscous damping (EVD) were analyzed and compared before and after repair and retrofit. The result indicates that the lateral strength increases by 22 in pushing direction and 27% in pulling direction. Moreover, the stiffness and ductility obtained before and after retrofit increase tremendously by 87.87% and 39.66%, respectively. Meanwhile, the energy absorption measured by equivalent viscous damping obtained after retrofit increase by 12.34% in pulling direction. It can be concluded that the proposed retrofit method is capable to increase the lateral strength capacity, stiffness and energy absorption of double unit TFB.

Keywords: tunnel form building, in-plane lateral cyclic loading, crack pattern, lateral strength, stiffness, ductility, equivalent viscous damping, repair and retrofit

Procedia PDF Downloads 338

Authors: Meenakshi Dahal

Abstract:

Generally, children start verbal communication by the age of eighteen months. Though they have difficulties in constructing complete sentences, they try to make their thought s understandable to the audience. By the age of 36 months, when they enroll in preschool, their Language and communication skills are enhanced. Children need plenty of classroom experiences that will help them to develop their oral language skills. Oral language is the primary means through which each individual child is enabled to structure, evaluate, describe and to express his/her experiences. In the context of multi lingual and multi-cultural country like Nepal, the languages used in preschool and the communities vary. In such a case, the language of instruction in the preschool is different from the language used by the children to communicate at home. Using qualitative research method the socio-cultural aspect of the language learning has been analyzed. This has been done by analyzing and exploring preschool activities as well as the language of instruction and communication in the preschools in rural Nepal. It is found that the language of instruction is different from the language of communications primarily used by the children. Teachers seldom use local language resulting in difficulties for the children to understand. Instead of recognizing their linguistic, social and cultural capitals teachers conform to using the Nepali language which the children are not familiar with. Children have to adapt to new language structures and patterns of usage resulting them to be slow in oral language and communication in the preschool. The paper concludes that teachers have to recognize the linguistic capitals of the children and schools need to be responsible to facilitate this process for all children, whatever their language background.

Keywords: children, language, preschool, socio-culture

Procedia PDF Downloads 379

Authors: D. Li

Abstract:

Optical thin films are used in a wide variety of optical components and there are many software tools programmed for advancing multilayer thin film design. The available software packages for designing the thin film structure may not provide optimum designs. Normally, almost all current software programs obtain their final designs either from optimizing a starting guess or by technique, which may or may not involve a pseudorandom process, that give different answers every time, depending upon the initial conditions. With the increasing power of personal computers, functional methods in optimization and synthesis of optical multilayer systems have been developed such as DGL Optimization, Simulated Annealing, Genetic Algorithms, Needle Optimization, Inductive Optimization and Flip-Flop Optimization. Among these, DGL Optimization has proved its efficiency in optical thin film designs. The application of the DGL optimization technique to the design of optical coating is presented. A DGL optimization technique is provided, and its main features are discussed. Guidelines on the application of the DGL optimization technique to various types of design problems are given. The innovative global optimization strategies used in a software tool, OnlyFilm, to optimize multilayer thin film designs through different filter designs are outlined. OnlyFilm is a powerful, versatile, and user-friendly thin film software on the market, which combines optimization and synthesis design capabilities with powerful analytical tools for optical thin film designers. It is also the only thin film design software that offers a true global optimization function.

Keywords: optical coatings, optimization, design software, thin film design

Procedia PDF Downloads 297

Authors: Rachida Ouysse

Abstract:

This paper proposes a constrained principal components (CnPC) estimator for efficient estimation of large-dimensional factor models when errors are cross sectionally correlated and the number of cross-sections (N) may be larger than the number of observations (T). Although principal components (PC) method is consistent for any path of the panel dimensions, it is inefficient as the errors are treated to be homoskedastic and uncorrelated. The new CnPC exploits the assumption of bounded cross-sectional dependence, which defines Chamberlain and Rothschild’s (1983) approximate factor structure, as an explicit constraint and solves a constrained PC problem. The CnPC method is computationally equivalent to the PC method applied to a regularized form of the data covariance matrix. Unlike maximum likelihood type methods, the CnPC method does not require inverting a large covariance matrix and thus is valid for panels with N ≥ T. The paper derives a convergence rate and an asymptotic normality result for the CnPC estimators of the common factors. We provide feasible estimators and show in a simulation study that they are more accurate than the PC estimator, especially for panels with N larger than T, and the generalized PC type estimators, especially for panels with N almost as large as T.

Keywords: high dimensionality, unknown factors, principal components, cross-sectional correlation, shrinkage regression, regularization, pseudo-out-of-sample forecasting

Procedia PDF Downloads 137

Authors: Khalid Al Mutairi, Mashhor Mansor, Magdy El-Bana, Saud L. Al-Rowaily, Asyraf Mansor

Abstract:

The present study was carried out in 20 islands of Farasan Archipelago in Saudi Arabia to describe the biogeography patterns of plants. A total of 191 species belonging to 129 genera and 53 families were identified. Following island biogeography theory, total plant species richness and their ecological groups were positively influenced by island size, number of habitats,elevation and were not affected by isolation. The high level of nestedness, the strong effect of area on total plant species richness and ecological groups, and the similarity of vegetation composition on the islands has several implications for conservation. In conclusion the large and richest islands in Farasan Archipelago such as Farasan Alkbir would conserve higher diversity than several smaller islands. This island also includes rare habitats like coral rocks and rare species. The invasion of the unique habitats such as wadi channels and water catchments in this island by the exotic tree Prosopis juliflora should be managed to conserve the native biodiversity. The protection of such critical habitats is very important on the other large island (e.g. Zufaf), due to their limited distribution in the country.

Keywords: island biogeography, conservation, farasan archipelago, saudi arabia, plant diversity

Procedia PDF Downloads 329

Authors: H. Beisch, J. Marx, S. Garlof, R. Shvets, I. I. Grygorchak, A. Kityk, B. Fiedler

Abstract:

Carbon materials, especially three-dimensional carbon foams, show very high potential in the application as electrode material for energy storage systems such as batteries and supercapacitors with unique fast charging and discharging times. Regarding their high specific surface areas (SSA) high specific capacities can be reached. Globugraphite is a newly developed carbon foam with an interconnected globular carbon morphology. Especially, this foam has a statistically distributed hierarchical pore structure resulting from the manufacturing process based on sintered ceramic templates which are synthetized during a final chemical vapor deposition (CVD) process. For morphology characterization scanning electron (SEM) and transmission electron microscopy (TEM) is used. In addition, the SSA is carried out by nitrogen adsorption combined with the Brunauer–Emmett–Teller (BET) theory. Electrochemical measurements in organic and inorganic electrolyte provide high energy densities and power densities resulting from ion absorption by forming an electrochemical double layer. All values are summarized in a Ragone Diagram. Finally, power densities up to 833 W/kg and energy densities up to 48 Wh/kg could be achieved. The corresponding SSA is between 376 m²/g and 859 m²/g. For organic electrolyte a specific capacity of 71 F/g at a density of 20 mg/cm³ was achieved.

Keywords: BET, CVD process, electron microscopy, Ragone diagram

Procedia PDF Downloads 163

Authors: M. Abdullah Al Faruque, Ram Balachandar

Abstract:

An experimental study with four different types of bed conditions was carried out to understand the effect of roughness in open channel flow at two different Reynolds numbers. The bed conditions include a smooth surface and three different roughness conditions which were generated using sand grains with a median diameter of 2.46 mm. The three rough conditions include a surface with distributed roughness, a surface with continuously distributed roughness and a sand bed with a permeable interface. A commercial two-component fibre-optic LDA system was used to conduct the velocity measurements. The variables of interest include the mean velocity, turbulence intensity, the correlation between the streamwise and the wall normal turbulence, Reynolds shear stress and velocity triple products. Quadrant decomposition was used to extract the magnitude of the Reynolds shear stress of the turbulent bursting events. The effect of roughness was evident throughout the flow depth. The results show that distributed roughness has the greatest roughness effect followed by the sand bed and the continuous roughness. Compared to the smooth bed, the streamwise turbulence intensity reduces but the vertical turbulence intensity increases at a location very close to the bed due to the introduction of roughness. Although the same sand grain is used to create the three different rough bed conditions, the difference in the turbulence intensity is an indication that the specific geometry of the roughness has an influence on turbulence structure.

Keywords: open channel flow, smooth and rough bed, Reynolds number, turbulence

Procedia PDF Downloads 310

Authors: Marcela Karmazínová, Michal Štrba, Miln Pilgr

Abstract:

The paper deals with the problems of the actual behavior, failure mechanism and load-carrying capacity of the special bolt connection developed and intended for the assembly connections of truss main girders of perspective railway temporary steel bridges. Within the framework of this problem solution, several types of structural details of assembly joints have been considered as the conceptual structural design. Based on the preliminary evaluation of advantages or disadvantages of these ones, in principle two basic structural configurations so-called “tooth” and “splice-plate” connections have been selected for the subsequent detailed investigation. This investigation is mainly based on the experimental verification of the actual behavior, strain and failure mechanism and corresponding strength of the connection, and on its numerical modeling using FEM. This paper is focused only on the cyclic loading (fatigue) tests results of “splice-plate” connections and their evaluation, which have already been finished. Simultaneously with the fatigue tests, the static loading tests have been realized too, but these ones, as well as FEM numerical modeling, are not the subject of this paper.

Keywords: Bolt assembly connection, cyclic loading, failure mechanisms, fatigue strength, steel structure, structural detail category, temporary railway bridge

Procedia PDF Downloads 431

Authors: Farrokh Taherkhani, Thomas Pinger, Max Gündel

Abstract:

The total economic damage caused by corrosion in Germany is estimated to be more than 3% of the GDP per year. Additionally, corrosion and suitable corrosion protection systems are also significant factors in the consideration of life cycle costs for steel hydraulic structures. In addition to classic coating systems (for example, epoxy resin or polyurethane), zinc and its alloys offer effective and very durable corrosion protection for steels. As a protective layer, hot-dip galvanizing prevents the corrosive media from penetrating into the steel matrix and acts as a sacrificial anode, which corrodes in preference to the steel. However, hot-dip galvanizing as a corrosion protection system has not yet been approved by the relevant authority, the Federal Waterways Engineering and Research Institute (BAW) in Germany. In order to make hot-dip galvanizing usable as a corrosion protection system for steel hydraulic structures in the future, different factors must be considered. These factors are (i) corrosion protection type, (ii) resistance to mechanical stress (i.e., abrasion resistance), (iii) combinability with cathodic corrosion protection, (iv) environmental effects and (v) the crack formation and propagation during hot-dip galvanizing. In this work, hot-dip galvanizing as a corrosion protection system for steel hydraulic steel structures, as well as open questions, are discussed. This paper is based on initial long-term exposure tests with corrosion protection systems consisting of hot-dip galvanizing and duplex systems.

Keywords: steel hydraulic structure, hot-dip galvanizing, corrosion, corrosion resistance, zinc coating, organic coating, duplex sytems

Procedia PDF Downloads 14

Authors: Alireza Barari

Abstract:

Physical activity and diet are factors that influence the body's structure. The purpose of this study was to compare the effects of four weeks of resistance training, and glutamine supplement consumption on growth hormone (GH), and Insulin-like growth factor 1 (IGF-1) Axis. 40 amateur male bodybuilders, participated in this study. They were randomly divided into four equal groups, Resistance (R), Glutamine (G), Resistance with Glutamine (RG), and Control (C). The R group was assigned to a four week resistance training program, three times/week, three sets of 10 exercises with 6-10 repetitions, at the 80-95% 1RM (One Repetition Maximum), with 120 seconds rest between sets), G group is consuming l-glutamine (0.1 g/kg^-1/day^-1), RG group resistance training with consuming L-glutamine, and C group continued their normal lifestyle without exercise training. GH, IGF1, IGFBP-III plasma levels were measured before and after the protocol. One-way ANOVA indicated significant change in GH, IGF, and IGFBP-III between the four groups, and the Tukey test demonstrated significant increase in GH, IGF1, IGFBP-III plasma levels in R, and RG group. Based upon these findings, we concluded that resistance training at 80-95% 1RM intensity, and resistance training along with oral glutamine shows significantly increase secretion of GH, IGF-1, and IGFBP-III in amateur males, but the addition of oral glutamine to the exercise program did not show significant difference in GH, IGF-1, and IGFBP-III.

Keywords: strength, glutamine, growth hormone, insulin-like growth factor 1

Procedia PDF Downloads 293

Authors: Wenjun Hou, Marek Perkowski

Abstract:

The Traveling Salesman problem is famous in computing and graph theory. In short, it asks for the Hamiltonian cycle of the least total weight in a given graph with N nodes. All variations on this problem, such as those with K-bounded-degree nodes, are classified as NP-complete in classical computing. Although several papers propose theoretical high-level designs of quantum algorithms for the Traveling Salesman Problem, no quantum circuit implementation of these algorithms has been created up to our best knowledge. In contrast to previous papers, the goal of this paper is not to optimize some abstract complexity measures based on the number of oracle iterations, but to be able to evaluate the real circuit and time costs of the quantum computer. Using the emerging quantum programming language Q# developed by Microsoft, which runs quantum circuits in a quantum computer simulation, an implementation of the bounded-degree problem and its respective quantum circuit were created. To apply Grover’s algorithm to this problem, a quantum oracle was designed, evaluating the cost of a particular set of edges in the graph as well as its validity as a Hamiltonian cycle. Repeating the Grover algorithm with an oracle that finds successively lower cost each time allows to transform the decision problem to an optimization problem, finding the minimum cost of Hamiltonian cycles. N log₂ K qubits are put into an equiprobablistic superposition by applying the Hadamard gate on each qubit. Within these N log₂ K qubits, the method uses an encoding in which every node is mapped to a set of its encoded edges. The oracle consists of several blocks of circuits: a custom-written edge weight adder, node index calculator, uniqueness checker, and comparator, which were all created using only quantum Toffoli gates, including its special forms, which are Feynman and Pauli X. The oracle begins by using the edge encodings specified by the qubits to calculate each node that this path visits and adding up the edge weights along the way. Next, the oracle uses the calculated nodes from the previous step and check that all the nodes are unique. Finally, the oracle checks that the calculated cost is less than the previously-calculated cost. By performing the oracle an optimal number of times, a correct answer can be generated with very high probability. The oracle of the Grover Algorithm is modified using the recalculated minimum cost value, and this procedure is repeated until the cost cannot be further reduced. This algorithm and circuit design have been verified, using several datasets, to generate correct outputs.

Keywords: quantum computing, quantum circuit optimization, quantum algorithms, hybrid quantum algorithms, quantum programming, Grover’s algorithm, traveling salesman problem, bounded-degree TSP, minimal cost, Q# language

Procedia PDF Downloads 171

Authors: Abed Ahmed, Mehrdad Asadi, Jennifer Martay

Abstract:

Stainless steel pipelines are crucial components to transportation and storage in the oil and gas industry. However, the rise of random attacks and vandalism on these pipes for their valuable transport has led to more security and protection for incoming surface impacts. These surface impacts can lead to large global deformations of the pipe and place the pipe under strain, causing the eventual failure of the pipeline. Therefore, understanding how these surface impact loads affect the pipes is vital to improving the pipes’ security and protection. In this study, experimental test and finite element analysis (FEA) have been carried out on EN3B stainless steel specimens to study the impact behaviour. Low velocity impact tests at 9 m/s with 16 kg dome impactor was used to simulate for high momentum impact for localised failure. FEA models of clamped and deformable boundaries were modelled to study the effect of the boundaries on the pipes impact behaviour on its impact resistance, using experimental and FEA approach. Comparison of experimental and FE simulation shows good correlation to the deformable boundaries in order to validate the robustness of the FE model to be implemented in pipe models with complex anisotropic structure.

Keywords: dynamic impact, deformable boundary conditions, finite element modelling, LS-DYNA, stainless steel pipe

Procedia PDF Downloads 135