Search results for: point clouds
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5022

Search results for: point clouds

4092 Levels of Students’ Understandings of Electric Field Due to a Continuous Charged Distribution: A Case Study of a Uniformly Charged Insulating Rod

Authors: Thanida Sujarittham, Narumon Emarat, Jintawat Tanamatayarat, Kwan Arayathanitkul, Suchai Nopparatjamjomras

Abstract:

Electric field is an important fundamental concept in electrostatics. In high-school, generally Thai students have already learned about definition of electric field, electric field due to a point charge, and superposition of electric fields due to multiple-point charges. Those are the prerequisite basic knowledge students holding before entrancing universities. In the first-year university level, students will be quickly revised those basic knowledge and will be then introduced to a more complicated topic—electric field due to continuous charged distributions. We initially found that our freshman students, who were from the Faculty of Science and enrolled in the introductory physic course (SCPY 158), often seriously struggled with the basic physics concepts—superposition of electric fields and inverse square law and mathematics being relevant to this topic. These also then resulted on students’ understanding of advanced topics within the course such as Gauss's law, electric potential difference, and capacitance. Therefore, it is very important to determine students' understanding of electric field due to continuous charged distributions. The open-ended question about sketching net electric field vectors from a uniformly charged insulating rod was administered to 260 freshman science students as pre- and post-tests. All of their responses were analyzed and classified into five levels of understandings. To get deep understanding of each level, 30 students were interviewed toward their individual responses. The pre-test result found was that about 90% of students had incorrect understanding. Even after completing the lectures, there were only 26.5% of them could provide correct responses. Up to 50% had confusions and irrelevant ideas. The result implies that teaching methods in Thai high schools may be problematic. In addition for our benefit, these students’ alternative conceptions identified could be used as a guideline for developing the instructional method currently used in the course especially for teaching electrostatics.

Keywords: alternative conceptions, electric field of continuous charged distributions, inverse square law, levels of student understandings, superposition principle

Procedia PDF Downloads 295
4091 Map UI Design of IoT Application Based on Passenger Evacuation Behaviors in Underground Station

Authors: Meng-Cong Zheng

Abstract:

When the public space is in an emergency, how to quickly establish spatial cognition and emergency shelter in the closed underground space is the urgent task. This study takes Taipei Station as the research base and aims to apply the use of Internet of things (IoT) application for underground evacuation mobility design. The first experiment identified passengers' evacuation behaviors and spatial cognition in underground spaces by wayfinding tasks and thinking aloud, then defined the design conditions of User Interface (UI) and proposed the UI design.  The second experiment evaluated the UI design based on passengers' evacuation behaviors by wayfinding tasks and think aloud again as same as the first experiment. The first experiment found that the design conditions that the subjects were most concerned about were "map" and hoping to learn the relative position of themselves with other landmarks by the map and watch the overall route. "Position" needs to be accurately labeled to determine the location in underground space. Each step of the escape instructions should be presented clearly in "navigation bar." The "message bar" should be informed of the next or final target exit. In the second experiment with the UI design, we found that the "spatial map" distinguishing between walking and non-walking areas with shades of color is useful. The addition of 2.5D maps of the UI design increased the user's perception of space. Amending the color of the corner diagram in the "escape route" also reduces the confusion between the symbol and other diagrams. The larger volume of toilets and elevators can be a judgment of users' relative location in "Hardware facilities." Fire extinguisher icon should be highlighted. "Fire point tips" of the UI design indicated fire with a graphical fireball can convey precise information to the escaped person. "Fire point tips" of the UI design indicated fire with a graphical fireball can convey precise information to the escaped person. However, "Compass and return to present location" are less used in underground space.

Keywords: evacuation behaviors, IoT application, map UI design, underground station

Procedia PDF Downloads 207
4090 Computation of Radiotherapy Treatment Plans Based on CT to ED Conversion Curves

Authors: B. Petrović, L. Rutonjski, M. Baucal, M. Teodorović, O. Čudić, B. Basarić

Abstract:

Radiotherapy treatment planning computers use CT data of the patient. For the computation of a treatment plan, treatment planning system must have an information on electron densities of tissues scanned by CT. This information is given by the conversion curve CT (CT number) to ED (electron density), or simply calibration curve. Every treatment planning system (TPS) has built in default CT to ED conversion curves, for the CTs of different manufacturers. However, it is always recommended to verify the CT to ED conversion curve before actual clinical use. Objective of this study was to check how the default curve already provided matches the curve actually measured on a specific CT, and how much it influences the calculation of a treatment planning computer. The examined CT scanners were from the same manufacturer, but four different scanners from three generations. The measurements of all calibration curves were done with the dedicated phantom CIRS 062M Electron Density Phantom. The phantom was scanned, and according to real HU values read at the CT console computer, CT to ED conversion curves were generated for different materials, for same tube voltage 140 kV. Another phantom, CIRS Thorax 002 LFC which represents an average human torso in proportion, density and two-dimensional structure, was used for verification. The treatment planning was done on CT slices of scanned CIRS LFC 002 phantom, for selected cases. Interest points were set in the lungs, and in the spinal cord, and doses recorded in TPS. The overall calculated treatment times for four scanners and default scanner did not differ more than 0.8%. Overall interest point dose in bone differed max 0.6% while for single fields was maximum 2.7% (lateral field). Overall interest point dose in lungs differed max 1.1% while for single fields was maximum 2.6% (lateral field). It is known that user should verify the CT to ED conversion curve, but often, developing countries are facing lack of QA equipment, and often use default data provided. We have concluded that the CT to ED curves obtained differ in certain points of a curve, generally in the region of higher densities. This influences the treatment planning result which is not significant, but definitely does make difference in the calculated dose.

Keywords: Computation of treatment plan, conversion curve, radiotherapy, electron density

Procedia PDF Downloads 486
4089 Detecting Natural Fractures and Modeling Them to Optimize Field Development Plan in Libyan Deep Sandstone Reservoir (Case Study)

Authors: Tarek Duzan

Abstract:

Fractures are a fundamental property of most reservoirs. Despite their abundance, they remain difficult to detect and quantify. The most effective characterization of fractured reservoirs is accomplished by integrating geological, geophysical, and engineering data. Detection of fractures and defines their relative contribution is crucial in the early stages of exploration and later in the production of any field. Because fractures could completely change our thoughts, efforts, and planning to produce a specific field properly. From the structural point of view, all reservoirs are fractured to some point of extent. North Gialo field is thought to be a naturally fractured reservoir to some extent. Historically, natural fractured reservoirs are more complicated in terms of their exploration and production efforts, and most geologists tend to deny the presence of fractures as an effective variable. Our aim in this paper is to determine the degree of fracturing, and consequently, our evaluation and planning can be done properly and efficiently from day one. The challenging part in this field is that there is no enough data and straightforward well testing that can let us completely comfortable with the idea of fracturing; however, we cannot ignore the fractures completely. Logging images, available well testing, and limited core studies are our tools in this stage to evaluate, model, and predict possible fracture effects in this reservoir. The aims of this study are both fundamental and practical—to improve the prediction and diagnosis of natural-fracture attributes in N. Gialo hydrocarbon reservoirs and accurately simulate their influence on production. Moreover, the production of this field comes from 2-phase plan; a self depletion of oil and then gas injection period for pressure maintenance and increasing ultimate recovery factor. Therefore, well understanding of fracturing network is essential before proceeding with the targeted plan. New analytical methods will lead to more realistic characterization of fractured and faulted reservoir rocks. These methods will produce data that can enhance well test and seismic interpretations, and that can readily be used in reservoir simulators.

Keywords: natural fracture, sandstone reservoir, geological, geophysical, and engineering data

Procedia PDF Downloads 93
4088 Physicochemical and Microbiological Assessment of Source and Stored Domestic Water from Three Local Governments in Ile-Ife, Nigeria

Authors: Mary A. Bisi-Johnson, Kehinde A. Adediran, Saheed A. Akinola, Hamzat A. Oyelade

Abstract:

Some of the main problems man contends with are the quantity (source and amount) and quality of water in Nigeria. Scarcity leads to water being obtained from various sources and microbiological contaminations of the water may thus occur between the collection point and the point of usage. Thus, this study aims to assess the general and microbiological quality of domestic water sources and household stored water used within selected areas in Ile-Ife, South-Western part of Nigeria for microbial contaminants. Physicochemical and microbiological examination were carried out on 45 source and stored water samples collected from well and spring in three different local government areas i.e. Ife east, Ife-south, and Ife-north. Physicochemical analysis included pH value, temperature, total dissolved solid, dissolved oxygen, and biochemical oxygen demand. Microbiology involved most probable number analysis, total coliform, heterotrophic plate, faecal coliform, and streptococcus count. The result of the physicochemical analysis of samples showed anomalies compared to acceptable standards with the pH value of 7.20-8.60 for stored and 6.50-7.80 for source samples as the total dissolved solids (TDS of stored 20-70mg/L, source 352-691mg/L), dissolved oxygen (DO of stored 1.60-9.60mg/L, source 1.60-4.80mg/L), biochemical oxygen demand (BOD stored 0.80-3.60mg/L, source 0.60-5.40mg/L). General microbiological quality indicated that both stored and source samples with the exception of a sample were not within acceptable range as indicated by analysis of the MPN/100ml which ranges (stored 290-1100mg/L, source 9-1100mg/L). Apart from high counts, most samples did not meet the World Health Organization standard for drinking water with the presence of some pathogenic bacteria and fungi such as Salmonella and Aspergillus spp. To annul these constraints, standard treatment methods should be adopted to make water free from contaminants. This will help identify common and likely water related infection origin within the communities and thus help guide in terms of interventions required to prevent the general populace from such infections.

Keywords: domestic, microbiology, physicochemical, quality, water

Procedia PDF Downloads 360
4087 [Keynote Talk]: Discovering Liouville-Type Problems for p-Energy Minimizing Maps in Closed Half-Ellipsoids by Calculus Variation Method

Authors: Lina Wu, Jia Liu, Ye Li

Abstract:

The goal of this project is to investigate constant properties (called the Liouville-type Problem) for a p-stable map as a local or global minimum of a p-energy functional where the domain is a Euclidean space and the target space is a closed half-ellipsoid. The First and Second Variation Formulas for a p-energy functional has been applied in the Calculus Variation Method as computation techniques. Stokes’ Theorem, Cauchy-Schwarz Inequality, Hardy-Sobolev type Inequalities, and the Bochner Formula as estimation techniques have been used to estimate the lower bound and the upper bound of the derived p-Harmonic Stability Inequality. One challenging point in this project is to construct a family of variation maps such that the images of variation maps must be guaranteed in a closed half-ellipsoid. The other challenging point is to find a contradiction between the lower bound and the upper bound in an analysis of p-Harmonic Stability Inequality when a p-energy minimizing map is not constant. Therefore, the possibility of a non-constant p-energy minimizing map has been ruled out and the constant property for a p-energy minimizing map has been obtained. Our research finding is to explore the constant property for a p-stable map from a Euclidean space into a closed half-ellipsoid in a certain range of p. The certain range of p is determined by the dimension values of a Euclidean space (the domain) and an ellipsoid (the target space). The certain range of p is also bounded by the curvature values on an ellipsoid (that is, the ratio of the longest axis to the shortest axis). Regarding Liouville-type results for a p-stable map, our research finding on an ellipsoid is a generalization of mathematicians’ results on a sphere. Our result is also an extension of mathematicians’ Liouville-type results from a special ellipsoid with only one parameter to any ellipsoid with (n+1) parameters in the general setting.

Keywords: Bochner formula, Calculus Stokes' Theorem, Cauchy-Schwarz Inequality, first and second variation formulas, Liouville-type problem, p-harmonic map

Procedia PDF Downloads 274
4086 Reliability Levels of Reinforced Concrete Bridges Obtained by Mixing Approaches

Authors: Adrián D. García-Soto, Alejandro Hernández-Martínez, Jesús G. Valdés-Vázquez, Reyna A. Vizguerra-Alvarez

Abstract:

Reinforced concrete bridges designed by code are intended to achieve target reliability levels adequate for the geographical environment where the code is applicable. Several methods can be used to estimate such reliability levels. Many of them require the establishment of an explicit limit state function (LSF). When such LSF is not available as a close-form expression, the simulation techniques are often employed. The simulation methods are computing intensive and time consuming. Note that if the reliability of real bridges designed by code is of interest, numerical schemes, the finite element method (FEM) or computational mechanics could be required. In these cases, it can be quite difficult (or impossible) to establish a close-form of the LSF, and the simulation techniques may be necessary to compute reliability levels. To overcome the need for a large number of simulations when no explicit LSF is available, the point estimate method (PEM) could be considered as an alternative. It has the advantage that only the probabilistic moments of the random variables are required. However, in the PEM, fitting of the resulting moments of the LSF to a probability density function (PDF) is needed. In the present study, a very simple alternative which allows the assessment of the reliability levels when no explicit LSF is available and without the need of extensive simulations is employed. The alternative includes the use of the PEM, and its applicability is shown by assessing reliability levels of reinforced concrete bridges in Mexico when a numerical scheme is required. Comparisons with results by using the Monte Carlo simulation (MCS) technique are included. To overcome the problem of approximating the probabilistic moments from the PEM to a PDF, a well-known distribution is employed. The approach mixes the PEM and other classic reliability method (first order reliability method, FORM). The results in the present study are in good agreement whit those computed with the MCS. Therefore, the alternative of mixing the reliability methods is a very valuable option to determine reliability levels when no close form of the LSF is available, or if numerical schemes, the FEM or computational mechanics are employed.

Keywords: structural reliability, reinforced concrete bridges, combined approach, point estimate method, monte carlo simulation

Procedia PDF Downloads 346
4085 Leça da Palmeira Revisited: Sixty-Seven Years of Recurring Work by Álvaro Siza

Authors: Eduardo Jorge Cabral dos Santos Fernandes

Abstract:

Over the last sixty-seven years, Portuguese architect Álvaro Siza Vieira designed several interventions for the Leça da Palmeira waterfront. With this paper, we aim to analyze the history of this set of projects in a chronological approach, seeking to understand the connections that can be established between them. Born in Matosinhos, a fishing and industrial village located near Porto, Álvaro Siza built a remarkable relationship with Leça da Palmeira (a neighboring village located to the north) from a personal and professional point of view throughout his life: it was there that he got married (in the small chapel located next to the Boa Nova lighthouse) and it was there that he designed his first works of great impact, the Boa Nova Tea House and the Ocean Swimming Pool, today classified as national monuments. These two works were the subject of several projects spaced over time, including recent restoration interventions designed by the same author. However, the marks of Siza's intervention in this territory are not limited to these two cases; there were other projects designed for this territory, which we also intend to analyze: the monument to the poet António Nobre (1967-80), the unbuilt project for a restaurant next to Piscina das Marés (presented in 1966 and redesigned in 1993), the reorganization of the Avenida da Liberdade (with a first project, not carried out, in 1965-74, and a reformulation carried out between 1998 and 2006) and, finally, the project for the new APDL facilities, which completes Avenida da Liberdade to the south (1995). Altogether, these interventions are so striking in this territory, from a landscape, formal, functional, and tectonic point of view, that it is difficult to imagine this waterfront without their presence. In all cases, the relationship with the site explains many of the design options. Time after time, the conditions of the pre-existing territory (also affected by the previous interventions of Siza) were considered, so each project created a new circumstance, conditioning the following interventions. This paper is part of a more comprehensive project, which aims to analyze the work of Álvaro Siza in its fundamental relationship with the site.

Keywords: Álvaro Siza, contextualism, Leça da Palmeira, landscape

Procedia PDF Downloads 31
4084 Euthanasia with Reference to Defective Newborns: An Analysis

Authors: Nibedita Priyadarsini

Abstract:

It is said that Ethics has a wide range of application which mainly deals with human life and human behavior. All ethical decisions are ultimately concerned with life and death. Both life and death must be considered dignified. Medical ethics with its different topics mostly deals with life and death concepts among which euthanasia is one. Various types of debates continue over Euthanasia long since. The question of putting an end to someone’s life has aroused controversial in legal sphere as well as in moral sphere. To permit or not to permit has remained an enigma the world over. Modern medicine is in the stage of transcending limits that cannot be set aside. The morality of allowing people to die without treatment has become more important as methods of treatment have become more sophisticated. Allowing someone to die states an essential recognition that there is some point in any terminal illness when further curative treatment has no purpose and the patient in such situation should allow dying a natural death in comfort, peace, and dignity, without any interference from medical science and technology. But taking a human life is in general sense is illogical in itself. It can be said that when we kill someone, we cause the death; whereas if we merely let someone die, then we will not be responsible for anyone’s death. This point is often made in connection with the euthanasia cases and which is often debatable. Euthanasia in the pediatric age group involves some important issues that are different from those of adult issues. The main distinction that occurs is that the infants and newborns and young children are not able to decide about their future as the adult does. In certain cases, where the child born with some serious deformities with no hope of recovery, in that cases doctor decide not to perform surgery in order to remove the blockage, and let the baby die. Our aim in this paper is to examine, whether it is ethically justified to withhold or to apply euthanasia on the part of the defective infant. What to do with severely defective infants from earliest time if got to know that they are not going to survive at all? Here, it will deal mostly with the ethics in deciding the relevant ethical concerns in the practice of euthanasia with the defective newborns issues. Some cases in relation to disabled infants and newborn baby will be taken in order to show what to do in a critical condition, that the patient and family members undergoes and under which condition those could be eradicated, if not all but some. The final choice must be with the benefit of the patient.

Keywords: ethics, medical ethics, euthanasia, defective newborns

Procedia PDF Downloads 204
4083 Initial Palaeotsunami and Historical Tsunami in the Makran Subduction Zone of the Northwest Indian Ocean

Authors: Mohammad Mokhtari, Mehdi Masoodi, Parvaneh Faridi

Abstract:

history of tsunami generating earthquakes along the Makran Subduction Zone provides evidence of the potential tsunami hazard for the whole coastal area. In comparison with other subduction zone in the world, the Makran region of southern Pakistan and southeastern Iran remains low seismicity. Also, it is one of the least studied area in the northwest of the Indian Ocean regarding tsunami studies. We present a review of studies dealing with the historical /and ongoing palaeotsunamis supported by IGCP of UNESCO in the Makran Subduction Zone. The historical tsunami presented here includes about nine tsunamis in the Makran Subduction Zone, of which over 7 tsunamis occur in the eastern Makran. Tsunami is not as common in the western Makran as in the eastern Makran, where a database of historical events exists. The historically well-documented event is related to the 1945 earthquake with a magnitude of 8.1moment magnitude and tsunami in the western and eastern Makran. There are no details as to whether a tsunami was generated by a seismic event before 1945 off western Makran. But several potentially large tsunamigenic events in the MSZ before 1945 occurred in 325 B.C., 1008, 1483, 1524, 1765, 1851, 1864, and 1897. Here we will present new findings from a historical point of view, immediately, we would like to emphasize that the area needs to be considered with higher research investigation. As mentioned above, a palaeotsunami (geological evidence) is now being planned, and here we will present the first phase result. From a risk point of view, the study shows as preliminary achievement within 20 minutes the wave reaches to Iranian as well Pakistan and Oman coastal zone with very much destructive tsunami waves capable of inundating destructive effect. It is important to note that all the coastal areas of all states surrounding the MSZ are being developed very rapidly, so any event would have a devastating effect on this region. Although several papers published about modelling, seismology, tsunami deposits in the last decades; as Makran is a forgotten subduction zone, more data such as the main crustal structure, fault location, and its related parameter are required.

Keywords: historical tsunami, Indian ocean, makran subduction zone, palaeotsunami

Procedia PDF Downloads 131
4082 Some Tips for Increasing Online Services Safety

Authors: Mohsen Rezaee

Abstract:

Although robust security softwares, including anti-viruses, anti-spywares, anti-spam and firewalls are amalgamated with new technologies such as safe zone, hybrid cloud, sand box and etc., and although it can be said that they have managed to prepare highest level of security against viruses, spywares and other malwares in 2012, in fact, hacker attacks to websites are increasingly becoming more and more complicated. Because of security matters developments it can be said it was expected to happen so. Here in this work we try to point out some functional and vital notes to enhance security on the web, enabling the user to browse safely in unlimited web world and to use virtual space securely.

Keywords: firewalls, security, web services, computer science

Procedia PDF Downloads 404
4081 Analysis of Cultural Influences on Quality Management by Comparison of Japanese and German Enterprises

Authors: Hermann Luecken, Young Won Park, Judith M. Puetter

Abstract:

Quality is known to be the accordance of product characteristics and customer requirements. Both the customer requirements and the assessment of the characteristics of the product with regard to the fulfillment of customer requirements are subject to cultural influences. Of course, the processes itself which lead to product manufacturing is also subject to cultural influences. In the first point, the cultural background of the customer influences the quality, in the second point, it is the cultural background of the employees and the company that influences the process itself. In times of globalization products are manufactured at different locations around the world, but typically the quality management system of the country in which the mother company is based is used. This leads to significantly different results in terms of productivity, product quality and process efficiency at the different locations, although the same quality management system is in use. The aim of an efficient and effective quality management system is therefore not doing the same at all locations, but to have the same result at all locations. In the past, standardization was used to achieve the same results. Recent investigations show that this is not the best way to achieve the same characteristics of product quality and production performance. In the present work, it is shown that the consideration of cultural aspects in the design of processes, production systems, and quality management systems results in a significantly higher efficiency and a quality improvement. Both Japanese and German companies were investigated with comparative interviews. The background of this selection is that in most cases the cultural difference regarding industrial processes between Germany and Japan is high. At the same time, however, the customer expectations regarding the product quality are very similar. Interviews were conducted with experts from German and Japanese companies; in particular, companies were selected that operate production facilities both in Germany and in Japan. The comparison shows that the cultural influence on the respective production performance is significant. Companies that adapt the design of their quality management and production systems to the country where the production site is located have a significantly higher productivity and a significantly higher quality of the product than companies that work with a centralized system.

Keywords: comparison of German and Japanese production systems, cultural influence on quality management, expert interviews, process efficiency

Procedia PDF Downloads 160
4080 A Holistic Approach for Technical Product Optimization

Authors: Harald Lang, Michael Bader, A. Buchroithner

Abstract:

Holistic methods covering the development process as a whole – e.g. systems engineering – have established themselves in product design. However, technical product optimization, representing improvements in efficiency and/or minimization of loss, usually applies to single components of a system. A holistic approach is being defined based on a hierarchical point of view of systems engineering. This is subsequently presented using the example of an electromechanical flywheel energy storage system for automotive applications.

Keywords: design, product development, product optimization, systems engineering

Procedia PDF Downloads 624
4079 Nonequilibrium Effects in Photoinduced Ultrafast Charge Transfer Reactions

Authors: Valentina A. Mikhailova, Serguei V. Feskov, Anatoly I. Ivanov

Abstract:

In the last decade the nonequilibrium charge transfer have attracted considerable interest from the scientific community. Examples of such processes are the charge recombination in excited donor-acceptor complexes and the intramolecular electron transfer from the second excited electronic state. In these reactions the charge transfer proceeds predominantly in the nonequilibrium mode. In the excited donor-acceptor complexes the nuclear nonequilibrium is created by the pump pulse. The intramolecular electron transfer from the second excited electronic state is an example where the nuclear nonequilibrium is created by the forward electron transfer. The kinetics of these nonequilibrium reactions demonstrate a number of peculiar properties. Most important from them are: (i) the absence of the Marcus normal region in the free energy gap law for the charge recombination in excited donor-acceptor complexes, (ii) extremely low quantum yield of thermalized charge separated state in the ultrafast charge transfer from the second excited state, (iii) the nonexponential charge recombination dynamics in excited donor-acceptor complexes, (iv) the dependence of the charge transfer rate constant on the excitation pulse frequency. This report shows that most of these kinetic features can be well reproduced in the framework of stochastic point-transition multichannel model. The model involves an explicit description of the nonequilibrium excited state formation by the pump pulse and accounts for the reorganization of intramolecular high-frequency vibrational modes, for their relaxation as well as for the solvent relaxation. The model is able to quantitatively reproduce complex nonequilibrium charge transfer kinetics observed in modern experiments. The interpretation of the nonequilibrium effects from a unified point of view in the terms of the multichannel point transition stochastic model allows to see similarities and differences of electron transfer mechanism in various molecular donor-acceptor systems and formulates general regularities inherent in these phenomena. The nonequilibrium effects in photoinduced ultrafast charge transfer which have been studied for the last 10 years are analyzed. The methods of suppression of the ultrafast charge recombination, similarities and dissimilarities of electron transfer mechanism in different molecular donor-acceptor systems are discussed. The extremely low quantum yield of the thermalized charge separated state observed in the ultrafast charge transfer from the second excited state in the complex consisting of 1,2,4-trimethoxybenzene and tetracyanoethylene in acetonitrile solution directly demonstrates that its effectiveness can be close to unity. This experimental finding supports the idea that the nonequilibrium charge recombination in the excited donor-acceptor complexes can be also very effective so that the part of thermalized complexes is negligible. It is discussed the regularities inherent to the equilibrium and nonequilibrium reactions. Their fundamental differences are analyzed. Namely the opposite dependencies of the charge transfer rates on the dynamical properties of the solvent. The increase of the solvent viscosity results in decreasing the thermal rate and vice versa increasing the nonequilibrium rate. The dependencies of the rates on the solvent reorganization energy and the free energy gap also can considerably differ. This work was supported by the Russian Science Foundation (Grant No. 16-13-10122).

Keywords: Charge recombination, higher excited states, free energy gap law, nonequilibrium

Procedia PDF Downloads 325
4078 A Study on Shear Field Test Method in Timber Shear Modulus Determination Using Stereo Vision System

Authors: Niaz Gharavi, Hexin Zhang

Abstract:

In the structural timber design, the shear modulus of the timber beam is an important factor that needs to be determined accurately. According to BS EN 408, shear modulus can be determined using torsion test or shear field test method. Although torsion test creates pure shear status in the beam, it does not represent the real-life situation when the beam is in the service. On the other hand, shear field test method creates similar loading situation as in reality. The latter method is based on shear distortion measurement of the beam at the zone with the constant transverse load in the standardized four-point bending test as indicated in BS EN 408. Current testing practice code advised using two metallic arms act as an instrument to measure the diagonal displacement of the constructing square. Timber is not a homogenous material, but a heterogeneous and this characteristic makes timber to undergo a non-uniform deformation. Therefore, the dimensions and the location of the constructing square in the area with the constant transverse force might alter the shear modulus determination. This study aimed to investigate the impact of the shape, size, and location of the square in the shear field test method. A binocular stereo vision system was developed to capture the 3D displacement of a grid of target points. This approach is an accurate and non-contact method to extract the 3D coordination of targeted object using two cameras. Two group of three glue laminated beams were produced and tested by the mean of four-point bending test according to BS EN 408. Group one constructed using two materials, laminated bamboo lumber and structurally graded C24 timber and group two consisted only structurally graded C24 timber. Analysis of Variance (ANOVA) was performed on the acquired data to evaluate the significance of size and location of the square in the determination of shear modulus of the beam. The results have shown that the size of the square is an affecting factor in shear modulus determination. However, the location of the square in the area with the constant shear force does not affect the shear modulus.

Keywords: shear field test method, BS EN 408, timber shear modulus, photogrammetry approach

Procedia PDF Downloads 211
4077 Altered States of Consciousness in Narrative Cinema: Subjective Film Sound

Authors: Mladen Milicevic

Abstract:

In this paper, subjective film sound will be addressed as it gets represented in narrative cinema. First, 'meta-diegetic' sound will be briefly explained followed by transition to “oneiric” sound. The representation of oneiric sound refers to a situation where film characters are experiencing some sort of an altered state of consciousness. Looking at an antlered state of consciousness in terms of human brain processes will point out to the cinematic ways of expression, which 'mimic' those processes. Using several examples for different films will illustrate these points.

Keywords: oneiric, ASC, film, sound

Procedia PDF Downloads 374
4076 Human Pressure Threaten Swayne’s Hartebeest to Point of Local Extinction from the Savannah Plains of Nech Sar National Park, South Rift Valley, Ethiopia

Authors: Simon Shibru, Karen Vancampenhout, Jozef Deckers, Herwig Leirs

Abstract:

We investigated the population size of the endemic and endangered Swayne’s Hartebeest (Alcelaphus buselaphus swaynei) in Nech Sar National Park from 2012 to 2014 and document the major threats why the species is on the verge of local extinction. The park was once known for its abundant density of Swayne’s Hartebeest. We used direct total count methods for a census. We administered semi-structured interviews and open-ended questionnaires with senior scouts who are the member of the local communities. Historical records were obtained to evaluate the population trends of the animals since 1974. The density of the animal decreased from 65 in 1974 to 1 individual per 100 km2 in 2014 with a decline of 98.5% in the past 40 years. The respondents agreed that the conservation status of the park was in its worst condition ever now with only 2 Swayne’s Hartebeest left, with a rapid decline from 4 individuals in 2012 and 12 individuals in 2009. Mainly hunting and habitat loss, but also the unsuitable season of reproduction and shortage of forage as minor factors were identified as threats for a local extinction of the Swayne’s Hartebeests. On the other hand, predation, fire, disease, and ticks were not considered a cause for the declining trend. Hunting happens mostly out of some kind of revenge since the local community thought that they were pushed out from the land because of the presence of Swayne's Hartebeest in the area. Respondents agreed that the revenge action of the local communities was in response to their unwillingness to be displaced from the park in 1982/3. This conflict situation is resulting from the exclusionary wildlife management policy of the country. We conclude that the human interventions in general and illegal hunting, in particular, pushed the Swayne’s Hartebeest to a point of local extinction. Therefore, we recommend inclusive wildlife management approach for continuing existence of the park together with its natural resources so that sustainable use of the resources is in place.

Keywords: hunting, habitat destruction, local extinction, Nech Sar National Park, Swayne’s Hartebeest

Procedia PDF Downloads 474
4075 Key Findings on Rapid Syntax Screening Test for Children

Authors: Shyamani Hettiarachchi, Thilini Lokubalasuriya, Shakeela Saleem, Dinusha Nonis, Isuru Dharmaratne, Lakshika Udugama

Abstract:

Introduction: Late identification of language difficulties in children could result in long-term negative consequences for communication, literacy and self-esteem. This highlights the need for early identification and intervention for speech, language and communication difficulties. Speech and language therapy is a relatively new profession in Sri Lanka and at present, there are no formal standardized screening tools to assess language skills in Sinhala-speaking children. The development and validation of a short, accurate screening tool to enable the identification of children with syntactic difficulties in Sinhala is a current need. Aims: 1) To develop test items for a Sinhala Syntactic Structures (S3 Short Form) test on children aged between 3;0 to 5;0 years 2) To validate the test of Sinhala Syntactic Structures (S3 Short Form) on children aged between 3; 0 to 5; 0 years Methods: The Sinhala Syntactic Structures (S3 Short Form) was devised based on the Renfrew Action Picture Test. As Sinhala contains post-positions in contrast to English, the principles of the Renfrew Action Picture Test were followed to gain an information score and a grammar score but the test devised reflected the linguistic-specificity and complexity of Sinhala and the pictures were in keeping with the culture of the country. This included the dative case marker ‘to give something to her’ (/ejɑ:ʈə/ meaning ‘to her’), the instrumental case marker ‘to get something from’ (/ejɑ:gən/ meaning ‘from him’ or /gɑhən/ meaning ‘from the tree’), possessive noun (/ɑmmɑge:/ meaning ‘mother’s’ or /gɑhe:/ meaning ‘of the tree’ or /male:/ meaning ‘of the flower’) and plural markers (/bɑllɑ:/ bɑllo:/ meaning ‘dog/dogs’, /mɑlə/mɑl/ meaning ‘flower/flowers’, /gɑsə/gɑs/ meaning ‘tree/trees’ and /wɑlɑ:kulə/wɑlɑ:kulu/ meaning ‘cloud/clouds’). The picture targets included socio-culturally appropriate scenes of the Sri Lankan New Year celebration, elephant procession and the Buddhist ‘Wesak’ ceremony. The test was piloted with a group of 60 participants and necessary changes made. In phase 1, the test was administered to 100 Sinhala-speaking children aged between 3; 0 and 5; 0 years in one district. In this presentation on phase 2, the test was administered to another 100 Sinhala-speaking children aged between 3; 0 to 5; 0 in three districts. In phase 2, the selection of the test items was assessed via measures of content validity, test-retest reliability and inter-rater reliability. The age of acquisition of each syntactic structure was determined using content and grammar scores which were statistically analysed using t-tests and one-way ANOVAs. Results: High percentage agreement was found on test-retest reliability on content validity and Pearson correlation measures and on inter-rater reliability. As predicted, there was a statistically significant influence of age on the production of syntactic structures at p<0.05. Conclusions: As the target test items included generated the information and the syntactic structures expected, the test could be used as a quick syntactic screening tool with preschool children.

Keywords: Sinhala, screening, syntax, language

Procedia PDF Downloads 340
4074 Cultural Orientation as a Moderator between Social Support Needs and Psychological Well-Being among Canadian University Students

Authors: Allison Streutker, Josephine Tan

Abstract:

Universities across Canada have experienced unprecedented growth in international student enrollment from across the world. As cultural diversity in Canada and other countries increases, understanding the social support needs of all students is important for providing them with the assistance they need to thrive psychologically and academically. Those from individualistic cultural orientations tend to seek explicit social support, which involves expressly asking for assistance in times of stress. However, those from collectivistic cultural orientations are more likely to seek implicit social support, where encouragement is obtained from spending time among valued social groups without explicitly talking about problems. This study explored whether the relationship between the type of social support needs (implicit or explicit) and psychological and academic functioning might be moderated by cultural orientations (individualistic, collectivistic) among university students. Participants were 110 university students (70 women, 40 men; mean age = 24.8 years, SD = 6.6). They completed the Individualism and Collectivism Scale (ICS), Perceived Stress Scale (PSS), Interpersonal Support Evaluation List (ISEL) which assesses implicit and explicit social support, Satisfaction with Life Scale (SWLS), Scale of Positive and Negative Experience (SPANE) which yields positive and negative experience scores, Flourishing Scale (FS), and reported their grade point average (GPA) as a measure of academic performance. Moderated regression analysis demonstrated that, for those scoring lower on individualism, reporting lower level of implicit support predicted higher levels of perceived stress. For those scoring higher on individualism, lower levels of explicit social support predicted higher levels of perceived stress and a greater number of negative experiences. Generally, higher levels of implicit support were associated with greater satisfaction with life for all students, with the association becoming stronger among students with higher collectivism scores. No other significant findings were found. The results point to the value of considering the cultural orientations of students when designing programs to maintain and improve their sense of well-being.

Keywords: cultural orientation, social support, university students, well-being

Procedia PDF Downloads 236
4073 Investigating University Students' Attitudes towards Infertility in Terms of Socio-Demographic Variables

Authors: Yelda Kağnıcı, Seçil Seymenler, Bahar Baran, Erol Esen, Barışcan Öztürk, Ender Siyez, Diğdem M. Siyez

Abstract:

Infertility is the inability to reproduce after twelve months or longer unprotected sexual relationship. Although infertility is not a life threatening illness, it is considered as a serious problem for both the individual and the society. At this point, the importance of examining attitudes towards infertility is critical. Negative attitudes towards infertility may postpone individuals’ help seeking behaviors. The aim of this study is to investigate university students’ attitudes towards infertility in terms of socio-demographic variables (gender, age, taking sexual health education, existence of an infertile individual in the social network, plans about having child and behaviors about health). The sample of the study was 9693 university students attending to 21 universities in Turkey. Of the 9693 students, % 51.6 (n = 5002) were female, % 48.4 (n = 4691) were male. The data was collected by Attitudes toward Infertility Scale developed by researchers and Personal Information Form. In data analysis first frequencies were calculated, then in order to test whether there were significant differences in attitudes towards infertility scores of university students in terms of socio-demographic variables, one way ANOVA was conducted. According to the results, it was found that female students, students who had sexual health education, who have sexual relationship experience, who have an infertile individual in their social networks, who have child plans, who have high caffeine usage and who use alcohol regularly have more positive attitudes towards infertility. On the other hand, attitudes towards infidelity did not show significant differences in terms of age and cigarette usage. When the results of the study were evaluated in general, it was seen that university students’ attitudes towards infertility were negative. The attitudes of students who have high caffeine and alcohols usage were high. It can be considered that these students are aware that their social habits are risky. Female students’ positive attitudes might be explained by their gender role. The results point out that in order to decrease university students’ negative attitudes towards infertility, there is a necessity to develop preventive programs in universities.

Keywords: infertility, attitudes, sex, university students

Procedia PDF Downloads 247
4072 Management Trainee Program

Authors: Ambreen Amir Ali

Abstract:

In todays’ dynamic environment, it has become very crucial to have comprehensive management trainee program to hire future leaders of organization. It is being proved that fresh graduates mostly join organizations because of its institution but later on they leave organization because of their immediate manager or supervisor. The concept of coaching and mentoring in talent management systems are very important, because mentors are those who can advise, facilitate, help and support new entrants to advance in their career. When it comes to going for talent hunt, one point needs to be highlighted that MTs are the raw talent for your organization, now it’s the responsibility of employers to nourish them, polish and developed them so that they can enthusiastically take care of senior leadership roles.

Keywords: management trainee, retention, leadership roles, coaching

Procedia PDF Downloads 636
4071 Big Data Analysis on the Development of Jinan’s Consumption Centers under the Influence of E-Commerce

Authors: Hang Wang, Xiaoming Gao

Abstract:

The rapid development of e-commerce has significantly transformed consumer behavior and urban consumption patterns worldwide. This study explores the impact of e-commerce on the development and spatial distribution of consumption centers, with a particular focus on Jinan City, China. Traditionally, urban consumption centers are defined by physical commercial spaces, such as shopping malls and markets. However, the rise of e-commerce has introduced a shift towards virtual consumption hubs, with a corresponding impact on physical retail locations. Utilizing Gaode POI (Point of Interest) data, this research aims to provide a comprehensive analysis of the spatial distribution of consumption centers in Jinan, comparing e-commerce-driven virtual consumption hubs with traditional physical consumption centers. The study methodology involves gathering and analyzing POI data, focusing on logistics distribution for e-commerce activities and mobile charging point locations to represent offline consumption behavior. A spatial clustering technique is applied to examine the concentration of commercial activities and to identify emerging trends in consumption patterns. The findings reveal a clear differentiation between e-commerce and physical consumption centers in Jinan. E-commerce activities are dispersed across a wider geographic area, correlating closely with residential zones and logistics centers, while traditional consumption hubs remain concentrated around historical and commercial areas such as Honglou and the old city center. Additionally, the research identifies an ongoing transition within Jinan’s consumption landscape, with online and offline retail coexisting, though at different spatial and functional levels. This study contributes to urban planning by providing insights into how e-commerce is reshaping consumption behaviors and spatial structures in cities like Jinan. By leveraging big data analytics, the research offers a valuable tool for urban designers and planners to adapt to the evolving demands of digital commerce and to optimize the spatial layout of city infrastructure to better serve the needs of modern consumers.

Keywords: big data, consumption centers, e-commerce, urban planning, jinan

Procedia PDF Downloads 20
4070 Dissociation of CDS from CVA Valuation Under Notation Changes

Authors: R. Henry, J-B. Paulin, St. Fauchille, Ph. Delord, K. Benkirane, A. Brunel

Abstract:

In this paper, the CVA computation of interest rate swap is presented based on its rating. Rating and probability default given by Moody’s Investors Service are used to calculate our CVA for a specific swap with different maturities. With this computation, the influence of rating variation can be shown on CVA. The application is made to the analysis of Greek CDS variation during the period of Greek crisis between 2008 and 2011. The main point is the determination of correlation between the fluctuation of Greek CDS cumulative value and the variation of swap CVA due to change of rating

Keywords: CDS, computation, CVA, Greek crisis, interest rate swap, maturity, rating, swap

Procedia PDF Downloads 309
4069 MIMO Radar-Based System for Structural Health Monitoring and Geophysical Applications

Authors: Davide D’Aria, Paolo Falcone, Luigi Maggi, Aldo Cero, Giovanni Amoroso

Abstract:

The paper presents a methodology for real-time structural health monitoring and geophysical applications. The key elements of the system are a high performance MIMO RADAR sensor, an optical camera and a dedicated set of software algorithms encompassing interferometry, tomography and photogrammetry. The MIMO Radar sensor proposed in this work, provides an extremely high sensitivity to displacements making the system able to react to tiny deformations (up to tens of microns) with a time scale which spans from milliseconds to hours. The MIMO feature of the system makes the system capable of providing a set of two-dimensional images of the observed scene, each mapped on the azimuth-range directions with noticeably resolution in both the dimensions and with an outstanding repetition rate. The back-scattered energy, which is distributed in the 3D space, is projected on a 2D plane, where each pixel has as coordinates the Line-Of-Sight distance and the cross-range azimuthal angle. At the same time, the high performing processing unit allows to sense the observed scene with remarkable refresh periods (up to milliseconds), thus opening the way for combined static and dynamic structural health monitoring. Thanks to the smart TX/RX antenna array layout, the MIMO data can be processed through a tomographic approach to reconstruct the three-dimensional map of the observed scene. This 3D point cloud is then accurately mapped on a 2D digital optical image through photogrammetric techniques, allowing for easy and straightforward interpretations of the measurements. Once the three-dimensional image is reconstructed, a 'repeat-pass' interferometric approach is exploited to provide the user of the system with high frequency three-dimensional motion/vibration estimation of each point of the reconstructed image. At this stage, the methodology leverages consolidated atmospheric correction algorithms to provide reliable displacement and vibration measurements.

Keywords: interferometry, MIMO RADAR, SAR, tomography

Procedia PDF Downloads 195
4068 Hermitical Landscapes: The Congregation of Saint Paul of Serra De Ossa

Authors: Rolando Volzone

Abstract:

The Congregation of Saint Paul of Serra de Ossa (Ossa Mountain) was founded in 1482, originated by the eremitic movement of the homens da pobre vida (poor life men), which is documented since 1366. The community of hermits expanded up to the first half of the 15th century, mostly in southern Portugal in the Alentejo region. In 1578, following a process of institutionalization led by the Church, an autonomous congregation was set up, affiliated in the Hungarian Order of Saint Paul the First Hermit, until 1834, when the decree of dissolution of the religious orders disbanded all the convents and monasteries in Portugal. The architectural evidences that reached our days as a legacy of the hermitical movement in Serra de Ossa, although studied and analysed from an historical point of view, are still little known with respect to the architectural characteristics of its physical implantation and its relationship with the natural systems. This research intends to expose the appropriation process of the locus eremus as a starting point for the interpretation of this landscape, evidencing the close relationship between the religious experience and the physical space chosen to reach the perfection of the soul. The locus eremus is thus determined not only by practical aspects such as the absolute and relative location, orography, existence of water resources, or the King’s favoring to the religious and settlement action of the hermits, but also by spiritual aspects related to the symbolism of the physical elements present and the solitary walk of these men. These aspects, combined with the built architectural elements and other exerted human action, may be fertile ground for the definition of a hypothetical hermitical landscape based on the sufficiently distinctive characteristics that sustain it. The landscape built by these hermits is established as a cultural and material heritage, and its preservation is of utmost importance. They deeply understood this place and took advantage of its natural resources, manipulating them in an ecological and economically sustainable way, respecting the place, without overcoming its own genius loci but becoming part of it.

Keywords: architecture, congregation of Saint Paul of Serra de Ossa, heremitical landscape, locus eremus

Procedia PDF Downloads 233
4067 Identification of the Usage of Some Special Places in the Prehistoric Site of Tapeh Zagheh through Multi-Elemental Chemical Analysis of the Soil Samples

Authors: Iraj Rezaei, Kamal Al Din Niknami

Abstract:

Tapeh Zagheh is an important prehistoric site located in the central plateau of Iran, which has settlement layers of the Neolithic and Chalcolithic periods. For this research, 38 soil samples were collected from different parts of the site, as well as two samples from its outside as witnesses. Then the samples were analyzed by XRF. The purpose of this research was to identify some places with special usage for human activities in Tapeh Zagheh by measuring the amount of some special elements in the soil. The result of XRF analysis shows a significant amount of P and K in samples No.3 (fourth floor) and No.4 (third floor), probably due to certain activities such as food preparation and consumption. Samples No.9 and No.10 can be considered suitable examples of the hearths of the prehistoric period in the central plateau of Iran. The color of these samples was completely darkened due to the presence of ash, charcoal, and burnt materials. According to the XRF results, the soil of these hearths has very high amounts of elements such as P, Ca, Mn, S, K, and significant amounts of Ti, Fe, and Na. In addition, the elemental composition of sample No. 14, which was taken from a home waster, also has very high amounts of P, Mn, Mg, Ti, and Fe and high amounts of K and Ca. Sample No. 11, which is related to soil containing large amounts of waster of the kiln, along with a very strong increase in Cl and Na, the amount of elements such as K, Mg, and S has also increased significantly. It seems that the reason for the increase of elements such as Ti and Fe in some Tapeh Zagheh floors (for example, samples number 1, 2, 3, 4, 5) was the use of materials such as ocher mud or fire ash in the composition of these floors. Sample No. 13, which was taken from an oven located in the FIX trench, has very high amounts of Mn, Ti, and Fe and high amounts of P and Ca. Sample No. 15, which is related to House No. VII (probably related to a pen or a place where animals were kept) has much more phosphate compared to the control samples, which is probably due to the addition of animal excrement and urine to the soil. Sample No. 29 was taken from the north of the industrial area of Zagheh village (place of pottery kilns). The very low amount of index elements in sample No. 29 shows that the industrial activities did not extend to the mentioned point, and therefore, the range of this point can be considered as the boundary between the residential part of the Zagheh village and its industrial part.

Keywords: prehistory, multi-elemental analysis, Tapeh Zagheh, XRF

Procedia PDF Downloads 92
4066 Formalizing the Sense Relation of Hyponymy from Logical Point of View: A Study of Mathematical Linguistics in Farsi

Authors: Maryam Ramezankhani

Abstract:

The present research tries to study the possibility of formalizing the sense relation of hyponymy. It applied mathematical tools and also uses mathematical logic concepts especially those from propositional logic. In order to do so, firstly, it goes over the definitions of hyponymy presented in linguistic dictionaries and semantic textbooks. Then, it introduces a formal translation of the sense relation of hyponymy. Lastly, it examines the efficiency of the suggested formula by some examples of natural language.

Keywords: sense relations, hyponymy, formalizing, words’ sense relation, formalizing sense relations

Procedia PDF Downloads 239
4065 Towards Developing A Rural South African Child Into An Engineering Graduates With Conceptual And Critical Thinking Skills

Authors: Betty Kibirige

Abstract:

Students entering the University of Zululand (UNIZULU) Science Faculty mostly come with skills that allow them to prepare for exams and pass them in order to satisfy requirements for entry into a tertiary Institution. Some students hail from deep rural schools with limited facilities, while others come from well-resourced schools. Personal experience has shown that it may take a student the whole time at a tertiary institution following the same skills as those acquired in high school as a sure means of entering the next level in their development, namely a postgraduate program. While it is apparent that at this point in human history, it is totally impossible to teach all the possible content in any one subject, many academics approach teaching and learning from the traditional point of view. It therefore became apparent to explore ways of developing a graduate that will be able to approach life with skills that allows them to navigate knowledge by applying conceptual and critical thinking skills. Recently, the Science Faculty at the University of Zululand introduced two Engineering programs. In an endeavour to approach the development of the Engineering graduate in this institution to be able to tackle problem-solving in the present-day excessive information availability, it became necessary to study and review approaches used by various academics in order to settle for a possible best approach to the challenge at hand. This paper focuses on the development of a deep rural child in a graduate with conceptual and critical thinking skills as major attributes possessed upon graduation. For this purpose, various approaches were studied. A combination of these approaches was repackaged to form an approach that may appear novel to UNIZULU and the rural child, especially for the Engineering discipline. The approach was checked by offering quiz questions to students participating in an engineering module, observing test scores in the targeted module and make comparative studies. Test results are discussed in the article. It was concluded that students’ graduate attributes could be tailored subconsciously to indeed include conceptual and critical thinking skills, but through more than one approach depending mainly on the student's high school background.

Keywords: graduate attributes, conceptual skills, critical thinking skills, traditional approach

Procedia PDF Downloads 242
4064 Chemical and Biomolecular Detection at a Polarizable Electrical Interface

Authors: Nicholas Mavrogiannis, Francesca Crivellari, Zachary Gagnon

Abstract:

Development of low-cost, rapid, sensitive and portable biosensing systems are important for the detection and prevention of disease in developing countries, biowarfare/antiterrorism applications, environmental monitoring, point-of-care diagnostic testing and for basic biological research. Currently, the most established commercially available and widespread assays for portable point of care detection and disease testing are paper-based dipstick and lateral flow test strips. These paper-based devices are often small, cheap and simple to operate. The last three decades in particular have seen an emergence in these assays in diagnostic settings for detection of pregnancy, HIV/AIDS, blood glucose, Influenza, urinary protein, cardiovascular disease, respiratory infections and blood chemistries. Such assays are widely available largely because they are inexpensive, lightweight, and portable, are simple to operate, and a few platforms are capable of multiplexed detection for a small number of sample targets. However, there is a critical need for sensitive, quantitative and multiplexed detection capabilities for point-of-care diagnostics and for the detection and prevention of disease in the developing world that cannot be satisfied by current state-of-the-art paper-based assays. For example, applications including the detection of cardiac and cancer biomarkers and biothreat applications require sensitive multiplexed detection of analytes in the nM and pM range, and cannot currently be satisfied with current inexpensive portable platforms due to their lack of sensitivity, quantitative capabilities and often unreliable performance. In this talk, inexpensive label-free biomolecular detection at liquid interfaces using a newly discovered electrokinetic phenomenon known as fluidic dielectrophoresis (fDEP) is demonstrated. The electrokinetic approach involves exploiting the electrical mismatches between two aqueous liquid streams forced to flow side-by-side in a microfluidic T-channel. In this system, one fluid stream is engineered to have a higher conductivity relative to its neighbor which has a higher permittivity. When a “low” frequency (< 1 MHz) alternating current (AC) electrical field is applied normal to this fluidic electrical interface the fluid stream with high conductivity displaces into the low conductive stream. Conversely, when a “high” frequency (20MHz) AC electric field is applied, the high permittivity stream deflects across the microfluidic channel. There is, however, a critical frequency sensitive to the electrical differences between each fluid phase – the fDEP crossover frequency – between these two events where no fluid deflection is observed, and the interface remains fixed when exposed to an external field. To perform biomolecular detection, two streams flow side-by-side in a microfluidic T-channel: one fluid stream with an analyte of choice and an adjacent stream with a specific receptor to the chosen target. The two fluid streams merge and the fDEP crossover frequency is measured at different axial positions down the resulting liquid

Keywords: biodetection, fluidic dielectrophoresis, interfacial polarization, liquid interface

Procedia PDF Downloads 446
4063 Existence and Uniqueness of Solutions to Singular Higher Order Two-Point BVPs on Time Scales

Authors: Zhenjie Liu

Abstract:

This paper investigates the existence and uniqueness of solutions for singular higher order boundary value problems on time scales by using mixed monotone method. The theorems obtained are very general. For the different time scale, the problem may be the corresponding continuous or discrete boundary value problem.

Keywords: mixed monotone operator, boundary value problem, time scale, green's function, positive solution, singularity

Procedia PDF Downloads 256