Search results for: tuning phenomenon

Authors: Samuel Ahamefula

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Turbulent motion is a highly nonlinear and complex phenomenon, and its modelling is still very challenging. In this study, we developed a hybrid computational approach to accurately simulate fluid turbulence phenomenon. The focus is coupling and transitioning between Direct Numerical Simulation (DNS) and Large Eddy Simulating Wall Models (LES-WM) regions. In the framework, high-order fidelity fluid dynamical methods are utilized to simulate the unsteady compressible Navier-Stokes equations in the Eulerian format on the unstructured moving grids. The coupling and transitioning of DNS and LES-WM are conducted through the linearly staggered Dirichlet-Neumann coupling scheme. The high-fidelity framework is verified and validated based on namely, DNS ability for capture full range of turbulent scales, giving accurate results and LES-WM efficiency in simulating near-wall turbulent boundary layer by using wall models.

Keywords: computational methods, turbulence modelling, turbulence entropy, navier-stokes equations

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Authors: Devam Sheth

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Nuclear imaging with stress myocardial perfusion (stress test) is the preferred first line investigation for noninvasive evaluation of ischaemic heart condition. The sensitivity of this test is close to 90 % making it a very reliable test. However, rarely it gives a false negative result which can be explained by the phenomenon termed as “balanced ischaemia”. We present the case of a 78 year Caucasian female without any significant past cardiac history, who presents with chest pain and shortness of breath since one day. The initial ECG and cardiac enzymes were non-impressive. Few hours later, she had some substernal chest pain along with some ST segment depression in the lateral leads. Stress test comes back negative for any significant perfusion defects. However, given her typical symptoms, she underwent a cardiac catheterization which revealed significant triple vessel disease mandating her to get a bypass surgery. This unusual phenomenon of false nuclear stress test in the setting of positive ECG changes can be explained only by balanced ischemia wherein due to global myocardial ischemia, the stress test fails to reveal relative perfusion defects in the affected segments.

Keywords: balanced, false positive, ischemia, myocardial perfusion imaging

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Authors: J. Fernandez de Canete, S. Fernandez-Calvo, I. García-Moral

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This paper presents and discusses the application of the object-oriented modelling software SIMSCAPE to hydraulic systems, with particular reference to multivariable proportional-integral-derivative (PID) control. As a result, a particular modelling approach of a double cylinder-piston coupled system is proposed and motivated, and the SIMULINK based PID tuning tool has also been used to select the proper controller parameters. The paper demonstrates the usefulness of the object-oriented approach when both physical modelling and control are tackled.

Keywords: object-oriented modeling, multivariable hydraulic system, multivariable PID control, computer simulation

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Authors: Yudhajit Datta

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Will is a phenomenon that has puzzled humanity for a long time. It is a belief that Will Power of an individual affects the success achieved by an individual in life. It is thought that a person endowed with great will power can overcome even the most crippling setbacks of life while a person with a weak will cannot make the most of life even the greatest assets. Behavioral aspects of the human experience such as will are rarely subjected to quantitative study owing to the numerous uncontrollable parameters involved. This work is an attempt to subject the phenomena of will to the test of an artificial neural network. The claim being tested is that will power of an individual largely determines success achieved in life. In the study, an attempt is made to incorporate the behavioral phenomenon of will into a computational model using data pertaining to the success of individuals obtained from an experiment. A neural network is to be trained using data based upon part of the model, and subsequently used to make predictions regarding will corresponding to data points of success. If the prediction is in agreement with the model values, the model is to be retained as a candidate. Ultimately, the best-fit model from among the many different candidates is to be selected, and used for studying the correlation between success and will.

Keywords: will power, will, success, apathy factor, random factor, characteristic function, life story

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Authors: Tianchen Dai

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Shantytowns are special historical products in china, possessing strong particularity and typicality, the theoretical value and the practical significance of which are deemed to hold great importance in the modern development of residential areas in China. The renovation planning of shantytowns can be very challenging in terms of cultural inheritance. The traditional lifestyle, one of the key elements building up residents’ perception of affiliation, should be carried forward in the renovation planning of shantytowns. Mobile vending can be considered as a rare business model survived within modern commercial environment, thanks to the unique spatial characteristics of Chinese shantytowns. This article mainly investigates the unique phenomenon of mobile vending in shantytowns, discussing the operating mechanism and rationality behind this commercial phenomenon. For humanistic concern, the innovative conservation of mobile vending, as a means to preserve the vivacious traditional lifestyle of local residents, can be realized through substantial urban design strategies, including spatial design of public space, height control of the facades, and traffic management around and inside shantytowns.

Keywords: cultural inheritance, mobile vending, renovation planning, shantytowns

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Authors: Amanda Aliende da Matta

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This communication presents an aspect of phenomenon selection in an applied hermeneutic phenomenology study on care and vulnerability: the need to consider it as a situated universal. For that, we will first present the study and its methodology. Secondly, we will expose the need to understand phenomena as situation-defined, incorporating feminist thought. In an informatics class for 14 year olds, we explained the exercise: students have to make a 5 slide presentation about a topic of their choice. A does it on streetwear, B on Cristiano Ronaldo, C on Marvel, but J did it on Down Syndrome. Introducing it to the class, J explains the physical and cognitive differences caused by trisomy; when asked to explain it further, he says: "they are angels, teacher," and shows us a poster on his cellphone that says: if you laugh at a different child he will laugh with you because his innocence outweighs your ignorance. The anecdote shows, better than any theoretical explanation, something that some vulnerable people have; something beautiful and special but difficult to define. Let's call this something caring. The research has the main objective of accounting for the experience of caregiving in vulnerability, and it will be carried out with Applied Hermeneutic Phenomenology (AHP). The method's objective is to investigate the lived human experience in its pre-reflexive dimension to know its meaning structures. Contrary to other research methods, AHP does not produce theory about a specific context but seeks the meaning of the lived experience, in its characteristic of human experience. However, it is necessary that we understand care as defined in a concrete situation. We cannot start the research with an a priori definitive concept of care, or we would fall into the mistake of closing ourselves to only what we already know, as explained by Levinas. We incorporate, then, the notion of situated universals. Loyal to phenomenology, the definition of the phenomenon should start with an investigation of the word's etymology: the word cura, in its etymological root, means care. And care comes from the Latin word cogitātus/cōgĭto, which means "to pursue something in mind" and "to consider thoroughly." The verb cōgĭto, meanwhile, is composed of co- (altogether) and agitare (to deal with or think committedly about something, to concern oneself with) / ăgĭto (to set in motion, to move). Care, therefore, has in its origin a meditation on something, a concern about something, a verb that has a sense of action and movement. To care is to act out of concern for something/someone. This etymology, though, is not the final definition of the phenomenon, but only its skeleton. It needs to be embodied in the concrete situation to become a possible lived experience. And that means that the lived experience descriptions (LEDs) should be selected by taking into consideration how and if care was engendered in that concrete experience. Defining the phenomenon has to take into consideration situated knowledge.

Keywords: applied hermeneutic phenomenology, care ethics, hermeneutics, phenomenology, situated universalism

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Authors: Shun Horikoshi, Tohru Kawabe

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This study presents performance analysis results of SMC (Sliding mode control) with changing the chattering functions applied to slip suppression problem of electric vehicles (EVs). In SMC, chattering phenomenon always occurs through high frequency switching of the control inputs. It is undesirable phenomenon and degrade the control performance, since it causes the oscillations of the control inputs. Several studies have been conducted on this problem by introducing some general saturation function. However, study about whether saturation function was really best and the performance analysis when using the other functions, weren’t being done so much. Therefore, in this paper, several candidate functions for SMC are selected and control performance of candidate functions is analyzed. In the analysis, evaluation function based on the trade-off between slip suppression performance and chattering reduction performance is proposed. The analyses are conducted in several numerical simulations of slip suppression problem of EVs. Then, we can see that there is no difference of employed candidate functions in chattering reduction performance. On the other hand, in slip suppression performance, the saturation function is excellent overall. So, we conclude the saturation function is most suitable for slip suppression sliding mode control.

Keywords: sliding mode control, chattering function, electric vehicle, slip suppression, performance analysis

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Authors: Mohammad A. Obeidat, Ayman M. Mansour

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Capturing the dynamic behavior of the heart to improve control performance, enhance robustness, and support diagnosis is very important in establishing real time models for the heart. Control Techniques and strategies have been utilized to improve system costs, reliability, and estimation accuracy for different types of systems such as biomedical, industrial, and other systems that required tuning input/output relation and/or monitoring. Simulations are performed to illustrate potential applications of the technology. In this research, a new control technology scheme is used to enhance the performance of the Af system and meet the design specifications.

Keywords: atrial fibrillation, dynamic behavior, closed loop, signal, filter

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Authors: N. David, H. O. Gao

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Air pollution is a serious environmental threat on a global scale and can cause harm to human health, morbidity and premature mortality. Reliable monitoring and control systems are therefore necessary to develop coping skills against the hazards associated with this phenomenon. However, existing environmental monitoring means often do not provide a sufficient response due to practical and technical limitations. Commercial microwave links that form the infrastructure for transmitting data between cell phone towers can be harnessed to map rain at high tempo-spatial resolution. Rainfall causes a decrease in the signal strength received by these wireless communication links allowing it to be used as a built-in sensor network to map the phenomenon. In this study, we point to the potential that lies in this system to indirectly monitor areas where air pollution is reduced. The relationship between pollutant wash-off and rainfall provides an opportunity to acquire important spatial information about air quality using existing cell-phone tower signals. Since the density of microwave communication networks is high relative to any dedicated sensor arrays, it could be possible to rely on this available observation tool for studying precipitation scavenging on air pollutants, for model needs and more.

Keywords: air pollution, commercial microwave links, rainfall, washout

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Authors: I. Valdez, J. Perdomo, M. Colindres, N. Castro

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Today, digital servo systems are extensively used in industrial manufacturing processes, robotic applications, vehicles and other areas. In such control systems, control action is provided by digital controllers with different compensation algorithms, which are designed to meet specific requirements for a given application. Due to the constant search for optimization in industrial processes, it is of interest to design digital controllers that offer ease of realization, improved computational efficiency, affordable return rates, and ease of tuning that ultimately improve the performance of the controlled actuators. There is a vast range of options of compensation algorithms that could be used, although in the industry, most controllers used are based on a PID structure. This research article compares different types of digital compensators implemented in a servo system for DC motor position control. PID compensation is evaluated on its two most common architectures: PID position form (1 DOF), and PID speed form (2 DOF). State feedback algorithms are also evaluated, testing two modern control theory techniques: discrete state observer for non-measurable variables tracking, and a linear quadratic method which allows a compromise between the theoretical optimal control and the realization that most closely matches it. The compared control systems’ performance is evaluated through simulations in the Simulink platform, in which it is attempted to model accurately each of the system’s hardware components. The criteria by which the control systems are compared are reference tracking and disturbance rejection. In this investigation, it is considered that the accurate tracking of the reference signal for a position control system is particularly important because of the frequency and the suddenness in which the control signal could change in position control applications, while disturbance rejection is considered essential because the torque applied to the motor shaft due to sudden load changes can be modeled as a disturbance that must be rejected, ensuring reference tracking. Results show that 2 DOF PID controllers exhibit high performance in terms of the benchmarks mentioned, as long as they are properly tuned. As for controllers based on state feedback, due to the nature and the advantage which state space provides for modelling MIMO, it is expected that such controllers evince ease of tuning for disturbance rejection, assuming that the designer of such controllers is experienced. An in-depth multi-dimensional analysis of preliminary research results indicate that state feedback control method is more satisfactory, but PID control method exhibits easier implementation in most control applications.

Keywords: control, DC motor, discrete PID, discrete state feedback

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Authors: Phibankhamti Ryngnga

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It is a common phenomenon worldwide that farmland has been gradually converted for urban development particularly in the 21st century keeping in mind the population increase on the other hand. Since food demand and supply are not in equilibrium in urban set up, therefore, there is a need for alternative to feed the hungry urban settlers worldwide. In this regard, urban rooftop farming is the only way out to meet the growing demand for food production with the extra benefits of making our urban areas and cities greener and when the populace is exposed to nature and vegetation, it in turn provides an array of psychological benefits, from decreased anxiety to increased productivity. Bare roofs in cities absorb and then radiate heat — a phenomenon known as the “heat island effect. This increases energy usage and contributes to the poor air quality that often plagues big cities. But Urban rooftop farming do provide many solutions to help cool buildings, ultimately reducing carbon emissions, and by growing food in the communities they serve, rooftop farmers lessen the environmental impact of food transportation. This paper will emphasise the significance of Urban roof farming in the present century which in itself a multi-solution to various city problems.

Keywords: urban, roof farming, smart solution, sustainability

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Authors: Rana Mahmoud

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This study represents a systematic study of the Operational Transconductance Amplifiers capacitance (OTA-C) filters or as it is often called Gm-C filters. OTA-C filters have been paid a great attention for the last decades. As Gm-C filters operate in an open loop topology, this makes them flexible to perform in low and high frequencies. As such, Gm-C filters can be used in various wireless communication applications. Another property of Gm-C filters is its electronic tunability, thus different filter frequency characteristics can be obtained without changing the inductance and resistance values. This can be achieved by an OTA (Operational Transconductance Amplifier) and a capacitor. By tuning the OTA transconductance, the cut-off frequency will be tuned and different frequency responses are achieved. Different high-order analog filters can be design using Gm-C filters including low pass, high pass and band pass filters. 1st and 2nd order low pass, high pass and band pass filters are presented in this paper.

Keywords: Gm-C, filters, low-pass, high-pass, band-pass

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Authors: Sung-Suk Oh, Bong-Keun Kang, Sang-Wook Park, Hui-Jin Joo, Jong-Ryul Choi, Seong-Jun Lee, Jeong-Woo Sohn

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The imaging phantom is utilized for the verification, evaluation and tuning of the medical imaging device and system. Although it could be costly, 3D printing is an ideal technique for a rapid, customized, multi-modal phantom making. In this article, we propose the multi-modal phantom using 3D printing. First of all, the Dicom images for were measured by CT (Computed Tomography) and 3D X-ray systems (PET/CT and Angio X-ray system of Siemens) and then were analyzed. Finally, the 3D modeling was processed using Dicom images. The 3D printed phantom was scanned by PET/CT and MRI systems and then evaluated.

Keywords: imaging phantom, MRI (Magnetic Resonance Imaging), PET / CT (Positron Emission Tomography / Computed Tomography), 3D printing

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Authors: Mauro Cristeche

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This work begins with a very simple question: How does the State spend? Argentina is witnessing a process of growing nationalization of social life, so it is necessary to find out the explanations of the phenomenon on the specific dynamic of the capitalist mode of production in Argentina and its transformations in the last decades. Then the new question is: what happened in Argentina that could explain this phenomenon? Since the seventies, the capital growth in Argentina faces deep competitive problems. Until that moment the agrarian wealth had worked as a compensation mechanism, but it began to find its limits. In the meantime, some important demographical and structural changes had happened. The strategy of the capitalist class had to become to seek in the cheapness of the labor force the main source of compensation of its weakness. As a result, a tendency to worsen the living conditions and fragmentation of the working class started to develop, manifested by unemployment, underemployment, and the fall of the purchasing power of the salary as a highlighted fact. As a consequence, it is suggested that the role of the State became stronger and public expenditure increased, as a historical trend, because it has to intervene to face the contradictions and constant growth problems posed by the development of capitalism in Argentina. On the one hand, the State has to guarantee the process of buying the cheapened workforce and at the same time the process of reproduction of the working class. On the other hand, it has to help to reproduce the individual capitals but needs to ‘attack’ them in different ways. This is why the role of the State is said to be the general political representative to the national portion of the total social capital. What will be studied is the dynamic of the intervention of the Argentine State in the context of the particular national process of capital growth, and its dynamics in the last decades. What this paper wants to show are the main general causes that could explain the phenomenon of nationalization of the social life and how it has impacted the life conditions of the working class and the system of rights.

Keywords: Argentina, nationalization, public policies, rights, state

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Authors: Ming Lu, Xiaojun Li, Bodi Lu, Juehui Xing

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Earthquake damage phenomenon of each large earthquake gives comprehensive and profound real test to the dynamic performance and failure mechanism of different engineering structures. Cognitive engineering structure characteristics through seismic damage phenomenon are often far superior to expensive shaking table experiments. After the earthquake, people will record a variety of different types of engineering damage photos. However, a large number of earthquake damage photographs lack sufficient information and reduce their using value. To improve the research value and the use efficiency of engineering seismic damage photographs, this paper objects to explore and show seismic damage background information, which includes the earthquake magnitude, earthquake intensity, and the damaged structure characteristics. From the research requirement in earthquake engineering field, the authors use the 2008 China Wenchuan M8.0 earthquake photographs, and provide four kinds of attribute indexes and classification, which are seismic information, structure types, earthquake damage parts and disaster causation factors. The final object is to set up an engineering structural seismic damage database based on these four attribute indicators and classification, and eventually build a website providing seismic damage photographs.

Keywords: attribute index, classification method, earthquake damage picture, engineering structure

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Authors: Rizka Yunita, Mas Aji Rizki Wijayanto

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Computational fluid dynamics (CFD) is the solution to explain how fluid dynamics behavior. In this work, we obtain the effect of channel width of two-dimensional fluid visualization. Using a horizontal water tunnel and flowing soap film, we got a visualization of continuous film that can be observe a graphical overview of the flow that occurs on a space or field in which the fluid flow. The horizontal water tunnel we used, divided into three parts, expansion area, parallel area that used to test the data, and contraction area. The width of channel is the boundary of parallel area with the originally width of 7.2 cm, and the variation of channel width we observed is about 1 cm and its times. To compute the velocity, vortex shedding, and other physical parameters of fluid, we used the cyclinder circular as an obstacle to create a von Karman vortex in fluid and analyzed that phenomenon by using Particle Imaging Velocimetry (PIV) method and comparing Reynolds number and Strouhal number from the visualization we got. More than width the channel, the film is more turbulent and have a separation zones that occurs of uncontinuous flowing fluid.

Keywords: flow visualization, width of channel, vortex, Reynolds number, Strouhal number

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Authors: Hamid Goharnejad, Milad Sadeghpoor Moalem, Mahmood Zakeri Niri, Leili Sadeghi Khalegh Abadi

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While there are many benefits to using reservoir dams, their break leads to destructive effects. From the viewpoint of International Committee of Large Dams (ICOLD), dam break means the collapse of whole or some parts of a dam; thereby the dam will be unable to hold water. Therefore, studying dam break phenomenon and prediction of its behavior and effects reduces losses and damages of the mentioned phenomenon. One of the most common types of reservoir dams is embankment dam. Overtopping in embankment dams occurs because of flood discharge system inability in release inflows to reservoir. One of the most important issues among managers and engineers to evaluate the performance of the reservoir dam rim when sliding into the storage, creating waves is large and long. In this study, the effects of floods which caused the overtopping of the dam have been investigated. It was assumed that spillway is unable to release the inflow. To determine outflow hydrograph resulting from dam break, numerical model using Flow-3D software and empirical equations was used. Results of numerical models and their comparison with empirical equations show that numerical model and empirical equations can be used to study the flood resulting from dam break.

Keywords: embankment dam break, empirical equations, Taleghan dam, Flow-3D numerical model

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Authors: Supriya H. S., Chandrakala B. M.

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Deep learning based models have been recently successful adoption for network traffic prediction. However, training a deep learning model for various prediction tasks is considered one of the critical tasks due to various reasons. This research work develops Multi-Layer Hybrid Network (MLHN) for network traffic prediction and analysis; MLHN comprises the three distinctive networks for handling the different inputs for custom feature extraction. Furthermore, an optimized and efficient parameter-tuning algorithm is introduced to enhance parameter learning. MLHN is evaluated considering the “Big Data Challenge” dataset considering the Mean Absolute Error, Root Mean Square Error and R^2as metrics; furthermore, MLHN efficiency is proved through comparison with a state-of-art approach.

Keywords: MLHN, network traffic prediction

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Authors: A. E. Agbogu

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While scholars have predicted that identity politics (or what is euphemistically referred to as ethnic politics in Nigeria) were a dying phenomenon in other parts of the world, in Nigeria, it has remained the basis of political activity and has indeed become not only the unwritten law of all calculations in the political firmament of the country but also the ultimo ratio. We intend in the paper that follows to explore the reason for this unhealthy development. The paper seeks to offer explanations for the paradoxical reality of the upsurge of ethnic politics in Nigeria when in fact, the phenomenon is apparently on a downward spiral elsewhere in the world, particularly in countries that are at par with Nigeria in terms of national development. The paper is descriptive and qualitative and has relied on available data for its source of materials. Among other things, the paper locates identity politics as a tool in the hands of a national elite that has not transcended the limitations imposes by the shackles of the parsonian particularistic polar attributes which have tended to fixate their weltanschauung or world view on attachments that are unpardonably primordial. In the event, ethnicity becomes a veritable instrument not only for cheap sectional mobilization but also a means for seeking access to the so-called national cake. It is recommended that a way out of this socio-politico malady is the creation of a political arrangement that conduces to the gravitational tendency which will lead to the transfer of loyalties away from the extant ethno-nationalities to the centre.

Keywords: ethnicism, development, crisis, identity politics

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Authors: Samira Cherid, Samir Bentata, F. Zahira Meghoufel, Sabria Terkhi, Yamina Sefir, Fatima Bendahma, Bouabdellah Bouadjemi, Ali Z. Itouni

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In this work, we examined the propagation of light in one-dimensional systems is examined by means of the random dimer model. The introduction of defect elements, randomly in the studied system, breaks down the Anderson localization and provides a set of propagating delocalized modes at the corresponding conventional dimer resonances. However, tuning suitably the defect dimer resonance on the host ones (or vice versa), the transmission magnitudes can be enhanced providing the optimized ballistic transmission regime as an average response. Hence, ballistic optical filters can be conceived at desired wavelengths.

Keywords: photonic crystals, random dimer model, ballistic resonance, localization and transmission

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Authors: Anam Gopi

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The undesired torque and flux ripple may occur in conventional direct torque control (DTC) induction motor drive. DTC can improve the system performance at low speeds by continuously tuning the regulator by adjusting the Kp, Ki values. In this Teaching Learning Based Optimization (TLBO) is proposed to adjust the parameters (Kp, Ki) of the speed controller in order to minimize torque ripple, flux ripple, and stator current distortion. The TLBO based PI controller has resulted is maintaining a constant speed of the motor irrespective of the load torque fluctuations.

Keywords: teaching learning based optimization, direct torque control, PI controller

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Authors: Richu J. Babu, Sony Mathew, Sharon Rony Jacob, Soney C. George, Jibin C. Jacob

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Human hair is a non-biodegradable waste available in plenty throughout the world but is rarely explored for applications in engineering fields. Tensile strength of human hair ranges from 170 to 220 MPa. This property of human hair can be made use in the field of making bio-composites[1]. The composite is prepared by commixing the human hair and natural rubber in a two roll mill along with additives followed by vulcanization. Here the concentration of the human hair is varied by fine-tuning the fiber length as 20 mm and sundry tests like tensile, abrasion, tear and hardness were conducted. While incrementing the fiber length up to a certain range the mechanical properties shows superior amendments.

Keywords: human hair, natural rubber, composite, vulcanization, fiber loading

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Authors: Yoonsuh Jung, Steven N. MacEachern

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Check loss function is used to define quantile regression. In the prospect of cross validation, it is also employed as a validation function when underlying truth is unknown. However, our empirical study indicates that the validation with check loss often leads to choosing an over estimated fits. In this work, we suggest a modified or L2-adjusted check loss which rounds the sharp corner in the middle of check loss. It has a large effect of guarding against over fitted model in some extent. Through various simulation settings of linear and non-linear regressions, the improvement of check loss by L2 adjustment is empirically examined. This adjustment is devised to shrink to zero as sample size grows.

Keywords: cross-validation, model selection, quantile regression, tuning parameter selection

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Authors: Natalia Alzate-Carvajal, Diego A. Acevedo-Guzman, Victor Meza-Laguna, Mario H. Farias, Luis A. Perez-Rey, Edgar Abarca-Morales, Victor A. Garcia-Ramirez, Vladimir A. Basiuk, Elena V. Basiuk

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Direct covalent functionalization of prefabricated free-standing graphene oxide paper (GOP) is considered as the only approach suitable for systematic tuning of thermal, mechanical and electronic characteristics of this important class of carbon nanomaterials. At the same time, the traditional liquid-phase functionalization protocols can compromise physical integrity of the paper-like material up to its total disintegration. To avoid such undesirable effects, we explored the possibility of employing an alternative, solvent-free strategy for facile and nondestructive functionalization of GOP with two representative aliphatic amines, 1-octadecylamine (ODA) and 1,12-diaminododecane (DAD), as well as with two aromatic amines, 1-aminopyrene (AP) and 1,5-diaminonaphthalene (DAN). The functionalization was performed under moderate heating at 150-180 °C in vacuum. Under such conditions, it proceeds through both amidation and epoxy ring opening reactions. Comparative characterization of pristine and amine-functionalized GOP mats was carried out by using Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopy (XPS), thermogravimetric (TGA) and differential thermal analysis, scanning electron and atomic force microscopy (SEM and AFM, respectively). Besides that, we compared the stability in water, wettability, electrical conductivity and elastic (Young's) modulus of GOP mats before and after amine functionalization. The highest content of organic species was obtained in the case of GOP-ODA, followed by GOP-DAD, GOP-AP and GOP-DAN samples. The covalent functionalization increased mechanical and thermal stability of GOP, as well as its electrical conductivity. The magnitude of each effect depends on the particular chemical structure of amine employed, which allows for tuning a given GOP property. Morphological characterization by using SEM showed that, compared to pristine graphene oxide paper, amine-modified GOP mats become relatively ordered layered assemblies, in which individual GO sheets are organized in a near-parallel pattern. Financial support from the National Autonomous University of Mexico (grants DGAPA-IN101118 and IN200516) and from the National Council of Science and Technology of Mexico (CONACYT, grant 250655) is greatly appreciated. The authors also thank David A. Domínguez (CNyN of UNAM) for XPS measurements and Dr. Edgar Alvarez-Zauco (Faculty of Science of UNAM) for the opportunity to use TGA equipment.

Keywords: amines, covalent functionalization, gas-phase, graphene oxide paper

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Authors: A. Bahieldin, A. Atef, S. Edris, N. O. Gadalla, S. M. Hassan, M. A. Al-Kordy, A. M. Ramadan, A. S. M. Al- Hajar, F. M. El-Domyati

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The idea of this work is based on a natural exciting phenomenon suggesting that suppression of genes related to the program cell death (or PCD) mechanism might help the plant cells to efficiently tolerate abiotic stresses. The scope of this work was the detection of PCD-related transcription factors (TFs) that might also be related to salt stress tolerance in plant. Two model plants, e.g., tobacco and Arabidopsis, were utilized in order to investigate this phenomenon. Occurrence of PCD was first proven by Evans blue staining and DNA laddering after tobacco leaf discs were treated with oxalic acid (OA) treatment (20 mM) for 24 h. A number of 31 TFs up regulated after 2 h and co-expressed with genes harboring PCD-related domains were detected via RNA-Seq analysis and annotation. These TFs were knocked down via virus induced gene silencing (VIGS), an RNA interference (RNAi) approach, and tested for their influence on triggering PCD machinery. Then, Arabidopsis SALK knocked out T-DNA insertion mutants in selected TFs analogs to those in tobacco were tested under salt stress (up to 250 mM NaCl) in order to detect the influence of different TFs on conferring salt tolerance in Arabidopsis. Involvement of a number of candidate abiotic-stress related TFs was investigated.

Keywords: VIGS, PCD, RNA-Seq, transcription factors

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Authors: Mahfoud Djebbar

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Stock dilution is a financial phenomenon resulting from the issue of additional shares by a company, or when holders convert their convertibles into new shares (capital increase). This issue and/or conversion enlarge the company’s share base that will result in marginal dilution (loss) for existing shareholders, and a benefit to new ones. Dilution issues have already been addressed in mainstream finance, particularly as far as information disclosure is concerned. However, in Islamic finance, stock dilution problems have not been deeply studied and the subject has not received sufficient attention from shariah-compatible firms, investors, and scholars. In this regard, this paper emphasises the forms, the effects of capital dilution on current shareholders as well as the ways and techniques of compensating them. And since the research in this field, in its Islamic perspective, is still in its infancy, the paper tries to analyse the phenomenon theoretically in detail using numerical examples, and expose some case studies of Shariah-compliant issuers of convertible Sukuk and how they compensate their existing shareholders. Finally, this study shows that the Sukuk issuers compensate old shareholders using the right of shuf’ah as a well known and practiced pre-emptive right in Islamic transactions centuries ago, as well as the ways conventional bond issuers use.

Keywords: compensating shareholders, convertible Sukuk, Islamic financial innovation, Shuf’ah

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Authors: Bang-Fuh Chen, Chih-Chun Chu

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The flow induced cylinder vibration or earthquake-induced cylinder motion are moving in an arbitrary direction with time. The phenomenon of flow across cylinder is highly nonlinear and a linear-superposition of flow pattern across separated oscillating direction of cylinder motion is not valid to obtain the flow pattern across a cylinder oscillating in multiple directions. A novel finite difference scheme is developed to simulate the viscous flow across an arbitrary moving circular cylinder and we call this a complete 2D (two-dimensional) flow-cylinder interaction. That is, the cylinder is simultaneously oscillating in x- and y- directions. The time-dependent domain and meshes associated with the moving cylinder are mapped to a fixed computational domain and meshes, which are time independent. The numerical results are validated by several bench mark studies. Several examples are introduced including flow across steam-wise, transverse oscillating cylinder and flow across rotating cylinder and flow across arbitrary moving cylinder. The Morison’s formula can not describe the complex interaction phenomenon between cross flow and oscillating circular cylinder. And the completed 2D computational fluid dynamic analysis should be made to obtain the correct hydrodynamic force acting on the cylinder.

Keywords: 2D cylinder, finite-difference method, flow-cylinder interaction, flow induced vibration

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Authors: Pushpa Debnath

Abstract:

Buddhism implies the ultimate methodology to obtain the acknowledgment to get out from cycling existence applied by the sutras. The Buddha’s natural methodology is the highest way of cessation from suffering existence. To be out of it, one must know the suffering before having tentativeness. According to the Buddha’s methodology, one can observe every being suffer from chronologically grasping craving. It is because lack of knowledge that the Buddha finds the four noble truths which are the basic states. These are suffering, the origin of suffering, cessation of suffering, and the path leading to the cessation of suffering. The Buddha describes that birth is suffering, aging is suffering, sickness is suffering, death is suffering, association with the unexpected is suffering, separation from the pleasant is suffering, and not receiving what one desires is suffering, In brief, the five aggregates of clinging are suffering. As the five aggregates are form, feeling, perception, mental formation, and consciousness. These are known as the matter that we identify with “You, Me” or “He.” The second truth cause of suffering is craving which has three types: craving for sense pleasures, craving for existence, and craving for non-existence. The third truth is the obliteration of craving, suffering can be eliminated to attain the Nibbana. The fourth truth is the path of liberation is the noble eight-fold path consisting of the right view, right intention, right speech, right action, right livelihood, right effort, right mindfulness, and right concentration. The six senses are the media of the eye, ear, nose, tongue, body, and mind sense faculties relating with the five aggregates and the six senses objects visual objects, sounds, smells, tastes, touch, and mind-objects that are contained by every visible being. The first five internal sense bases are material while the mind is a non-material phenomenon. Contact with the external world maintains by receiving through the six senses; visual objects through the eye, sounds through the ear, smells through the nose, tastes through the tongue, touch through the body, and mind-objects through sense faculties. These are the six senses a living being experiences by craving. Everything is conglomerated with all senses faculties through the natural phenomenon which are earth, water, fire, and air element. In this analysis, it is believed that beings are well adapted to the natural phenomenon. Everybody has fear of life because we have hatred, delusion, and anger which are the primary resources of falling into (Samsara) continuously that is the continuity of the natural way. These are the reasons for the suffering that chronically self-diluting through the threefold way. These are the roots of the entire beings suffering so the Buddha finds the enlightenment to uproot from cycling existence and the understanding of the natural consequence. When one could uproot ignorance, one could able to realize the ultimate happiness of Nirvana. From the craving of ignorance, everything starts to be present to the future which gives us mental agonies in existence.

Keywords: purification, morality, natural phenomenon, analysis, development of mind, observatory, Nirvana

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Authors: Sidi Mohamed Mesli, Mohamed Habchi, Mohamed Kotbi, Rafik Benallal, Abdelali Derouiche

Abstract:

Fluoride glasses with a nominal composition of BaMnMF7 (M = FeV assuming isomorphous replacement) have been structurally modelled through the simultaneous simulation of their neutron diffraction patterns by a reverse Monte Carlo (RMC) model and by a Rietveld for disordered materials (RDM) method. Model is consistent with an expected network of interconnected [MF6] polyhedra. The RMC results are accompanied by artificial satellite peaks. To remedy this problem, we use an extension of the RMC algorithm, which introduces an energy penalty term in acceptance criteria. This method is called the Hybrid Reverse Monte Carlo (HRMC) method. The idea of this paper is to apply the (HRMC) method to the title glasses, in order to make a study of the phenomenon nature of order and disorder by displaying and discussing the partial pair distribution functions (PDFs) g(r). We suggest that this method can be used to describe average correlations between components of fluoride glass or similar system.

Keywords: fluoride glasses, RMC simulation, neutron scattering, hybrid RMC simulation, Lennard-Jones potential, partial pair distribution functions

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Authors: Taha Ahmed Özbey, Sedat Nazlıbilek, Alparslan Çağrı Yapıcı

Abstract:

Combline cavity filters have gained significant attention in recent years due to their exceptional narrowband characteristics, high unloaded Q, remarkable out-of-band rejection, and versatile post-manufacturing tuning capabilities. These filters play a vital role in various wireless communication systems, radar applications, and other advanced technologies where stringent frequency selectivity and superior performance are required. This paper represents combined cavity filter design and implementation by coupling matrix synthesis. Limited filter length, 50 dB out-of-band rejection, and agile design were aimed. To do so, CAD tools and intuitive methods were used.

Keywords: cavity, band pass filter, cavity combline filter, coupling matrix synthesis

Procedia PDF Downloads 43