Search results for: power distribution

Authors: Rakan Alajmi, Rahaf Alnazzawi, Yara Aljefri, Abdullah Alafif, Ali Alraddadi, Awadh Alamri

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Background: The distribution of physicians in different specialties across Saudi Arabia is determined by the career choices of medical students. Dermatology residency program is one of the highly competitive programs here in Saudi Arabia. Assessing and understanding the factors perceived to be attractive in choosing dermatology will aid the directors of the specialty programs to plan for a more balanced workforce distribution to better suit the needs of the specialties. Aim: The aim of our study is to determine and assess the factors perceived to be significantly attractive when choosing dermatology as a future specialty. Methods: The study is a cross-sectional study conducted in King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia. A validated questionnaire was sent electronically to clinical year medical students. In addition to the questionnaire, gender, grade point average, preferred specialty, and other socio-demographic data were assessed. Results: A total of 121 clinical years medical students completed the questionnaire, 8 (6.6%) preferred dermatology as a specialty. 76 (62.8%) of the participants score a grade point average of more than 4.5 and 83 students (68.6%) chose their specialty during clinical years. The appeal of being a dermatologist (P= 0.047), the portrayal of different specialities in the media (P= 0.005), and the likelihood that dermatologists can influence patients’ lives (P=0.010) were shown to be significantly attractive factors. Conclusion: There are many factors that are affecting students’ choices when choosing a medical specialty. The appeal of being a dermatologist, the portrayal of different specialities in the media, and the likelihood that dermatologists can influence patients’ lives were shown to be significantly attractive factors when choosing dermatology as a future specialty. Recognizing medical students’ specialty perception will lead them to a proper specialty tailored to their needs.

Keywords: dermatology, career choice, medical specialties, student's perception

Procedia PDF Downloads 153

Authors: Yue Wang, Fan Chen

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After the economic reform in 1978, the urbanization in China has grown fast. It urged cities to expand in an unprecedented high speed. Villages around were annexed unprepared, and it turned out to be a new type of community called 'village in city.' Two things happened here. First, the locals gave up farming and turned to secondary industry and tertiary industry, as a result of losing their land. Secondly, attracted by the high income in cities and low rent here, plenty of migrants came into the community. This area is important to a city in rapid growth for providing a transitional zone. But thanks to its passivity and low development, 'village in city' has caused lots of trouble to the city. Densities of population and construction are both high, while facilities are severely inadequate. Unplanned and illegal structures are built, which creates a complex mixed-function area and leads to a bad residential area. Besides, the locals have a strong property right consciousness for the land. It holds back the transformation and development of the community. Although the land capitalization can bring significant benefits, it’s inappropriate to make a great financial compensation to the locals, and considering the large population of city migrants, it’s important to explore the relationship among the 'village in city,' city immigrants and the city itself. Taking the example of Hangzhou, this paper analyzed the developing process, functions spatial distribution, industrial structure and current traffic system of 'village in city.' Above the research on the community, this paper put forward a common method to make urban planning through the following ways: adding city functions, building civil facilities, re-planning functions spatial distribution, changing the constitution of local industry and planning new traffic system. Under this plan, 'village in city' finally can be absorbed into cities and make its own contribution to the urbanization.

Keywords: China, city immigrant, urbanization, village in city

Procedia PDF Downloads 217

Authors: Bruna P. De Souza, Ricardo C. De Almeida

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In some cities in the State of Parana – Brazil and in other countries atmospheric bromeliads (Tillandsia spp - Bromeliaceae) are considered weeds in trees, electric power lines, satellite dishes and other artificial supports. In this study, a numerical model was developed to simulate the seed dispersal of the Tillandsia recurvata species by wind with the objective of evaluating seeds displacement in the city of Ponta Grossa – PR, Brazil, since it is considered that the region is already infested. The model simulates the dispersal of each individual seed integrating parameters from the atmospheric boundary layer (ABL) and the local wind, simulated by the Weather Research Forecasting (WRF) mesoscale atmospheric model for the 2012 to 2015 period. The dispersal model also incorporates the approximate number of bromeliads and source height data collected from most infested electric power lines. The seeds terminal velocity, which is an important input data but was not available in the literature, was measured by an experiment with fifty-one seeds of Tillandsia recurvata. Wind is the main dispersal agent acting on plumed seeds whereas atmospheric turbulence is a determinant factor to transport the seeds to distances beyond 200 meters as well as to introduce random variability in the seed dispersal process. Such variability was added to the model through the application of an Inverse Fast Fourier Transform to wind velocity components energy spectra based on boundary-layer meteorology theory and estimated from micrometeorological parameters produced by the WRF model. Seasonal and annual wind means were obtained from the surface wind data simulated by WRF for Ponta Grossa. The mean wind direction is assumed to be the most probable direction of bromeliad seed trajectory. Moreover, the atmospheric turbulence effect and dispersal distances were analyzed in order to identify likely regions of infestation around Ponta Grossa urban area. It is important to mention that this model could be applied to any species and local as long as seed’s biological data and meteorological data for the region of interest are available.

Keywords: atmospheric turbulence, bromeliad, numerical model, seed dispersal, terminal velocity, wind

Procedia PDF Downloads 141

Authors: Anastasia Stamatiou, Markus Odermatt, Dominic Leemann, Ludger J. Fischer, Joerg Worlitschek

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The successful integration of thermal energy storage in industrial processes is expected to play an important role in the energy turnaround. Latent heat storage technologies can offer more compact thermal storage at a constant temperature level, in comparison to conventional, sensible thermal storage technologies. The focus of this study is the development of latent heat storage solutions based on the Phase Change Slurry (PCS) concept. Such systems promise higher energy densities both as refrigerants and as storage media while presenting better heat transfer characteristics than conventional latent heat storage technologies. This technology is expected to deliver high thermal power and high-temperature stability which makes it ideal for storage of process heat. An evaluation of important batch processes in industrial applications set the focus on materials with a melting point in the range of 55 - 90 °C. Aluminium ammonium sulfate dodecahydrate (NH₄Al(SO₄)₂·12H₂O) was chosen as the first interesting PCM for the next steps of this study. The ability of this material to produce slurries at the relevant temperatures was demonstrated in a continuous mode in a laboratory test-rig. Critical operational and design parameters were identified.

Keywords: esters, latent heat storage, phase change materials, thermal properties

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Authors: M. J. Suriani, F. Mansor, W. Siti Maizurah, I. Nurizwani

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Silicon Carbide (SiC) is one of the Silicon-based materials, which get interested by the researcher. SiC is an emerging semiconductor material, which has received a great deal of attention due to their application in high frequency and high power systems. Although its superior characteristic for a semiconductor material, its outstanding mechanical properties, chemical inertness and thermal stability has gained important aspect for a surface coating for deployment in extreme environments. Very high frequency (VHF)-PECVD technique utilized to deposit nano ns-SiC film in which variation in chamber pressure, substrate temperature, RF power and precursor gases flow rate will be investigated in order to get a good quality of thin film coating. Characterization of the coating performed in order to study the surface morphology, structural information. This performance of coating evaluated through corrosion test to determine the effectiveness of the coating for corrosion prevention. Ns-SiC film expected to possess better corrosion resistance and optical properties, as well as preserving the metal from the marine environment. Through this research project, corrosion protection performance by applying coating will be explored to obtain a great corrosion prevention method to the shipping and oil and gas industry in Malaysia. Besides, the cost of repair and maintenance spending by the government of Malaysia can be reduced through practicing this method.

Keywords: composite materials, marine corrosion, nano-composite, nano structure–coating

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Authors: A. T. Asutosh, J. Woo, M. Kouhirostami, M. Sam, A. Khantawang, C. Cuales, W. Ryor, C. Kibert

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Climate change and global warming vortex have grown to alarming proportions. Therefore, the need for a shift in the conceptualization of energy production is paramount. Energy practices have been created in the current situation. Fossil fuels continue their prominence, at the expense of renewable sources. Despite this abundance, a large percentage of the world population still has no access to electricity but there have been encouraging signs in global movement from nonrenewable to renewable energy but means to reverse climate change have been elusive. Worldwide, organizations have put tremendous effort into innovation. Conferences and exhibitions act as a platform that allows a broad exchange of information regarding trends in the renewable energy field. The Solar Power International (SPI) conference and exhibition is a gathering of concerned activists, and probably the largest convention of its kind. This study investigates current development in the renewable energy field, analyzing means by which industry is being applied to the issue. In reviewing the 2019 SPI conference, it was found innovations in recycling and assessing the environmental impacts of the solar products that need critical attention. There is a huge movement in the electrical storage but there exists a large gap in the development of security systems. This research will focus on solar energy, but impacts will be relevant to the entire renewable energy market.

Keywords: climate change, renewable energy, solar, trends, research, solar power international, SPI

Procedia PDF Downloads 109

Authors: Ahmed Ghachem, Denis Prud’homme, Rémi-Rabasa-Lhoret, M. Brochu

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Objective: To compare the effects of a CR on body composition, lipid profile and glucose homeostasis in obese postmenopausal women with and without MetS. Methods: Secondary analyses were performed on seventy-three inactive obese postmenopausal women (age: 57.7 ± 4.8 yrs; body mass index: 32.4 ± 4.6 kg/m2) who participated in the 6-month caloric restriction arm of a study of the Montreal-Ottawa New Emerging Team. The harmonized MetS definition was used to categorized participants with MetS [n = 20, 27.39%] and without MetS [n = 53, 72.61%]. Variables of interest were: body composition (DXA), body fat distribution (CT scan), glucose homeostasis at the fasting state and during a euglycemic/hyperinsulinemic clamp, fasting lipids and resting blood pressure. Results: By design, the MetS group had a worse cardiometabolic profile; while both groups were comparable for age. Fifty-five patients out of seventy-three displayed no change in MetS status after the intervention. Twelve participants out of twenty (or 60.0%) in the MetS group had no more MetS after weight loss (P= NS); while six participants out of fifty three (or 11.3%) in the other group developed the MetS after the intervention (P= NS). Overall, indices of body composition and body fat distribution improved significantly and similarly in both groups (P between 0.03 and 0.0001). Furthermore, with the exception of triglyceride levels and triglycerides/HDL-C ratio, which decrease significantly more in the MetS group (P ≤ 0.05), no difference was observed between groups for the other variables of the cardiometabolic profile. Conclusion: Despite no overall significant effects on MetS, heterogeneous results were obtained in response to weight loss in the present study; with some improving the MetS while other displaying deteriorations. Further studies are needed in order to identify factors and phenotypes associated with positive and negative cardiometabolic responses to CR intervention.

Keywords: menopause, obesity, physical inactivity, metabolic syndrome, caloric restriction, weight loss

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Authors: Abdelhak Djoudi, Hachemi Chekireb, El Madjid Berkouk

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The doubly fed induction generator (DFIG) received recently an important consideration in medium and high power wind energy conversion systems integration, due to its advantages compared to other generators types. The stator power sliding mode control (SPSMC) proves a great efficiency judge against other control laws and schemes. In the SPSMC laws elaborated by several authors, only the slide surface tracking conditions are elaborated using Lyapunov functions, and the boundedness of the DFIG states is never treated. Some works have validated theirs approaches by experiments results in the case of specified machines, but these verifications stay insufficient to generalize to other machines range. Adding to this argument, the DFIG states boundedness demonstration is widely suggested in goal to ensure that in the application of the SPSMC, the states evaluates within theirs tolerable bounds. Our objective in the present paper is to highlight the efficiency of the SPSMC by stability analysis. The boundedness of the DFIG states such as the stator current and rotor flux is discussed. Moreover, the states trajectories are finding using analytical proves taking into consideration the SPSMC gains.

Keywords: Doubly Fed Induction Generator (DFIG), Stator Powers Sliding Mode Control (SPSMC), lyapunov function, stability, states boundedness, trajectories mathematical proves

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Authors: Anna Słupik, Krzysztof Jaworski, Anna Mosiołek, Dariusz Białoszewski

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Background: Maintaining the correct body balance is essential in the prevention of falls in the elderly, which is especially important for women because of postmenopausal osteoporosis and the serious consequences of falls. One of the exercise methods which is very popular among adults, and which may affect body balance in a positive way is the pilates method. The aim of the study was to evaluate the effect of regular pilates exercises on the ability to maintain body balance in static conditions in adult healthy women. Material and methods: The study group consisted of 20 healthy women attending pilates twice a week for at least 1 year. The control group consisted of 20 healthy women physically inactive. Women in the age range from 35 to 50 years old without pain in musculoskeletal system or other pain were only qualified to the groups. Body balance was assessed using MatScan VersaTek platform with Sway Analysis Module based on Matscan Clinical 6.7 software. The balance was evaluated under the following conditions: standing on both feet with eyes open, standing on both feet with eyes closed, one-leg standing (separately on the right and left foot) with eyes open. Each test lasted 30 seconds. The following parameters were calculated: estimated size of the ellipse of 95% confidence, the distance covered by the Center of Gravity (COG), the size of the maximum shift in the sagittal and frontal planes and load distribution between the left and right foot, as well as between rear- and forefoot. Results: It was found that there is significant difference between the groups in favor of the study group in the size of the confidence ellipse and maximum shifts of COG in the sagittal plane during standing on both feet, both with the eyes open and closed (p < 0.05). While standing on one leg both on the right and left leg, with eyes opened there was a significant difference in favor of the study group, in terms of the size of confidence ellipse, the size of the maximum shifts in the sagittal and in the frontal plane (p < 0.05). There were no differences between the distribution of load between the right and left foot (standing with both feet), nor between fore- and rear foot (in standing with both feet or one-leg). Conclusions: 1. Static balance in women exercising regularly by pilates method is better than in inactive women, which may in the future prevent falls and their consequences. 2. The observed differences in maintaining balance in frontal plane in one-leg standing may indicate a positive impact of pilates exercises on the ability to maintain global balance in terms of the reduced support surface. 3. Pilates method can be used as a form preventive therapy for all people who are expected to have problems with body balance in the future, for example in chronic neurological disorders or vestibular problems. 4. The results have shown that further prospective randomized research on a larger and more representative group is needed.

Keywords: balance exercises, body balance, pilates, pressure distribution, women

Procedia PDF Downloads 318

Authors: Staniek Halina

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The inappropriate trace elements supply such as iron(III) and chromium(III) may be risk factors of many metabolic disorders (e.g., anemia, diabetes, as well cause toxic effect). However, little is known about their mutual interactions and their impact on these disturbances. The effects of Cr(III) supplementation with a deficit or excess supply of Fe(III) in vivo conditions are not known yet. The objective of the study was to investigate the combined effect of different Fe(III) levels in the diet and simultaneous Cr(III) supplementation on the Ca distribution in organs in healthy rats. The assessment was based on a two-factor (2x3) experiment carried out on 54 female Wistar rats (Rattus norvegicus). The animals were randomly divided into 9 groups and for 6 weeks, they were fed semi-purified diets AIN-93 with three different Fe(III) levels in the diet as a factor A [control (C) 45 mg/kg (100% Recommended Daily Allowance for rodents), deficient (D) 5 mg/kg (10% RDA), and oversupply (H) 180 mg/kg (400% RDA)]. The second factor (B) was the simultaneous dietary supplementation with Cr(III) at doses of 1, 50 and 500 mg/kg of the diet. Iron(III) citrate was the source of Fe(III). The complex of Cr(III) with propionic acid, also called Cr₃ or chromium(III) propionate (CrProp), was used as a source of Cr(III) in the diet. The Ca content of analysed samples (liver, kidneys, spleen, heart, and femur) was determined with the Atomic Absorption Spectrometry (AAS) method. It was found that different dietary Fe(III) supply as well as Cr(III) supplementation independently and in combination influenced Ca metabolism in healthy rats. Regardless of the supplementation of Cr(III), the oversupply of Fe(III) (180 mg/kg) decreased the Ca content in the liver and kidneys, while it increased the Ca saturation of bone tissue. High Cr(III) doses lowered the hepatic Ca content. Moreover, it tended to decrease the Ca content in the kidneys and heart, but this effect was not statistically significant. The combined effect of the experimental factors on the Ca content in the liver and the femur was observed. With the increase in the Fe(III) content in the diet, there was a decrease in the Ca level in the liver and an increase in bone saturation, and the additional Cr(III) supplementation intensified those effects. The study proved that the different Fe(III) content in the diet, independently and in combination with Cr(III) supplementation, affected the Ca distribution in organisms of healthy rats.

Keywords: calcium, chromium(III), iron(III), rats, supplementation

Procedia PDF Downloads 198

Authors: J. F. Gonzalez-Rojo, Federico Lluesma-Rodriguez, Temoatzin Gonzalez

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Hyperloop, a new mode of transport, is gaining significance. It consists of the use of a ground-based transport system which includes a levitation system, that avoids rolling friction forces, and which has been covered with a tube, controlling the inner atmosphere lowering the aerodynamic drag forces. Thus, hyperloop is proposed as a solution to the current limitation on ground transportation. Rolling and aerodynamic problems, that limit large speeds for traditional high-speed rail or even maglev systems, are overcome using a hyperloop solution. Zeleros is one of the companies developing technology for hyperloop application worldwide. It is working on a concept that reduces the infrastructure cost and minimizes the power consumption as well as the losses associated with magnetic drag forces. For this purpose, Zeleros proposes a Hybrid ElectroMagnetic Suspension (EMS) for its prototype. In the present manuscript an active and optimal electromagnetic suspension levitation method based on nearly zero power consumption individual modules is presented. This system consists of several hybrid permanent magnet-coil levitation units that can be arranged along the vehicle. The proposed unit manages to redirect the magnetic field along a defined direction forming a magnetic circuit and minimizing the loses due to field dispersion. This is achieved using an electrical steel core. Each module can stabilize the gap distance using the coil current and either linear or non-linear control methods. The ratio between weight and levitation force for each unit is 1/10. In addition, the quotient between the lifted weight and power consumption at the target gap distance is 1/3 [kg/W]. One degree of freedom (DoF) (along the gap direction) is controlled by a single unit. However, when several units are present, a 5 DoF control (2 translational and 3 rotational) can be achieved, leading to the full attitude control of the vehicle. The proposed system has been successfully tested reaching TRL-4 in a laboratory test bench and is currently in TRL-5 state development if the module association in order to control 5 DoF is considered.

Keywords: active optimal control, electromagnetic levitation, HEMS, high-speed transport, hyperloop

Procedia PDF Downloads 146

Authors: Moses C. Siame, Kazutoshi Haga, Atsushi Shibayama

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This study investigates the removal of silica, alumina and phosphorus as impurities from Sanje iron ore using wet high-intensity magnetic separation (WHIMS). Sanje iron ore contains low-grade hematite ore found in Nampundwe area of Zambia from which iron is to be used as the feed in the steelmaking process. The chemical composition analysis using X-ray Florence spectrometer showed that Sanje low-grade ore contains 48.90 mass% of hematite (Fe₂O₃) with 34.18 mass% as an iron grade. The ore also contains silica (SiO₂) and alumina (Al₂O₃) of 31.10 mass% and 7.65 mass% respectively. The mineralogical analysis using X-ray diffraction spectrometer showed hematite and silica as the major mineral components of the ore while magnetite and alumina exist as minor mineral components. Mineral particle distribution analysis was done using scanning electron microscope with an X-ray energy dispersion spectrometry (SEM-EDS) and images showed that the average mineral size distribution of alumina-silicate gangue particles is in order of 100 μm and exists as iron-bearing interlocked particles. Magnetic separation was done using series L model 4 Magnetic Separator. The effect of various magnetic separation parameters such as magnetic flux density, particle size, and pulp density of the feed was studied during magnetic separation experiments. The ore with average particle size of 25 µm and pulp density of 2.5% was concentrated using pulp flow of 7 L/min. The results showed that 10 T was optimal magnetic flux density which enhanced the recovery of 93.08% of iron with 53.22 mass% grade. The gangue mineral particles containing 12 mass% silica and 3.94 mass% alumna remained in the concentrate, therefore the concentrate was further treated in the second stage WHIMS using the same parameters from the first stage. The second stage process recovered 83.41% of iron with 67.07 mass% grade. Silica was reduced to 2.14 mass% and alumina to 1.30 mass%. Accordingly, phosphorus was also reduced to 0.02 mass%. Therefore, the two stage magnetic separation process was established using these results.

Keywords: Sanje iron ore, magnetic separation, silica, alumina, recovery

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Authors: Santi Termprasertsakul, Jakkrich Jearviriyaboonya

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This paper studies the market power and pricing behavior of products in iron and steel industry by investigating the impact of vertical product differentiation (VPD) on exchange rate pass-through (ERPT). Vietnam has become one of the major trading partners of Thailand since 2017. The iron and steel export value to Vietnam is more than $300 million a year. Particularly, the average growth rate of importing iron and steel is approximately 30% per year. The VPD is applied to analyze the quality difference of iron and steel between Thailand and Vietnam. The 20 products in iron and steel industry are investigated. The monthly pricing behavior of Harmonized Commodity Description and Coding System 4-digit products is observed from 2010 to 2019. The Nonlinear Autoregressive Distributed Lag is also used to analyze the asymmetry of ERPT in this paper. The empirical results basically reveal an incomplete pass-through between Thai Baht and Vietnamese Dong. The ERPT also varies with the degree of VPD. The product with higher VPD, indicating higher unit values, has higher ERPT. This result suggests the higher market power of the Thai iron and steel industry. In addition, the asymmetry of ERPT exists.

Keywords: exchange rate pass-through, iron and steel industry, pricing behavior, vertical product differentiation

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Authors: H. R. Goshayeshi, M. Khalouei, S. Azarberamman

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This paper presents an experimental investigation regarding the use of Fe2O3 nano particles added to kerosene as a working fluid, under magnetic field. The experiment was made on Oscillating Heat Pipe (OHP). The experiment was performed in order to measure the temperature distribution and compare the heat transfer rate of the oscillating heat pipe with and without magnetic Field. Results showed that the addition of Fe2o3 nano particles under magnetic field improved thermal performance of OHP, compare with non-magnetic field. Furthermore applying a magnetic field enhance the heat transfer characteristic of Fe2O3 in both start up and steady state conditions. This paper presents an experimental investigation regarding the use of Fe2O3 nano particles added to kerosene as a working fluid, under magnetic field. The experiment was made on Oscillating Heat Pipe (OHP). The experiment was performed in order to measure the temperature distribution and compare the heat transfer rate of the oscillating heat pipe with and without magnetic Field. Results showed that the addition of Fe2o3 nano particles under magnetic field improved thermal performance of OHP, compare with non-magnetic field. Furthermore applying a magnetic field enhance the heat transfer characteristic of Fe2O3 in both start up and steady state conditions.

Keywords: experimental, oscillating heat pipe, heat transfer, magnetic field

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Authors: Zachary Huffman, Joana Rocha

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Wall-pressure fluctuations induced by the turbulent boundary layer (TBL) developed over aircraft are a significant source of aircraft cabin noise. Since the power spectral density (PSD) of these pressure fluctuations is directly correlated with the amount of sound radiated into the cabin, the development of accurate empirical models that predict the PSD has been an important ongoing research topic. The sound emitted can be represented from the pressure fluctuations term in the Reynoldsaveraged Navier-Stokes equations (RANS). Therefore, early TBL empirical models (including those from Lowson, Robertson, Chase, and Howe) were primarily derived by simplifying and solving the RANS for pressure fluctuation and adding appropriate scales. Most subsequent models (including Goody, Efimtsov, Laganelli, Smol’yakov, and Rackl and Weston models) were derived by making modifications to these early models or by physical principles. Overall, these models have had varying levels of accuracy, but, in general, they are most accurate under the specific Reynolds and Mach numbers they were developed for, while being less accurate under other flow conditions. Despite this, recent research into the possibility of using alternative methods for deriving the models has been rather limited. More recent studies have demonstrated that an artificial neural network model was more accurate than traditional models and could be applied more generally, but the accuracy of other machine learning techniques has not been explored. In the current study, an original model is derived using a stepwise regression algorithm in the statistical programming language R, and TBL wall-pressure fluctuations PSD data gathered at the Carleton University wind tunnel. The theoretical advantage of a stepwise regression approach is that it will automatically filter out redundant or uncorrelated input variables (through the process of feature selection), and it is computationally faster than machine learning. The main disadvantage is the potential risk of overfitting. The accuracy of the developed model is assessed by comparing it to independently sourced datasets.

Keywords: aircraft noise, machine learning, power spectral density models, regression models, turbulent boundary layer wall-pressure fluctuations

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Authors: Lukasz Grabowski, Konrad Pietrykowski, Michal Bialy

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This paper presents the results of the research to verify the combustion in aircraft piston engine Asz62-IR. This engine was modernized and a type of ignition system was developed. Due to the high costs of experiments of a nine-cylinder 1,000 hp aircraft engine, a simulation technique should be applied. Therefore, computational fluid dynamics to simulate the combustion process is a reasonable solution. Accordingly, the tests for varied ignition advance angles were carried out and the optimal value to be tested on a real engine was specified. The CFD model was created with the AVL Fire software. The engine in the research had two spark plugs for each cylinder and ignition advance angles had to be set up separately for each spark. The results of the simulation were verified by comparing the pressure in the cylinder. The courses of the indicated pressure of the engine mounted on a test stand were compared. The real course of pressure was measured with an optical sensor, mounted in a specially drilled hole between the valves. It was the OPTRAND pressure sensor, which was designed especially to engine combustion process research. The indicated pressure was measured in cylinder no 3. The engine was running at take-off power. The engine was loaded by a propeller at a special test bench. The verification of the CFD simulation results was based on the results of the test bench studies. The course of the simulated pressure obtained is within the measurement error of the optical sensor. This error is 1% and reflects the hysteresis and nonlinearity of the sensor. The real indicated pressure measured in the cylinder and the pressure taken from the simulation were compared. It can be claimed that the verification of CFD simulations based on the pressure is a success. The next step was to research on the impact of changing the ignition advance timing of spark plugs 1 and 2 on a combustion process. Moving ignition timing between 1 and 2 spark plug results in a longer and uneven firing of a mixture. The most optimal point in terms of indicated power occurs when ignition is simultaneous for both spark plugs, but so severely separated ignitions are assured that ignition will occur at all speeds and loads of engine. It should be confirmed by a bench experiment of the engine. However, this simulation research enabled us to determine the optimal ignition advance angle to be implemented into the ignition control system. This knowledge allows us to set up the ignition point with two spark plugs to achieve as large power as possible.

Keywords: CFD model, combustion, engine, simulation

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Authors: Yuri Bizzoni, Marianne Reboul

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Our program compares French and Italian translations of Homer’s Odyssey, from the XVIth to the XXth century. We focus on the third point, showing how distributional semantics systems can be used both to improve alignment between different French translations as well as between the Greek text and a French translation. Although we focus on French examples, the techniques we display are completely language independent.

Keywords: classical receptions, computational linguistics, distributional semantics, Homeric poems, machine translation, translation studies, text alignment

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Authors: Guanlin Wu, Jiajia Yao, Fang Liu, Junshuai Xue, Jincheng Zhang, Yue Hao

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Owing to the excellent thermal conductivity and ultra-wide bandgap, Aluminum nitride (AlN)/Gallium nitride (GaN) is a highly promising material to achieve high breakdown voltage and output power devices among III-nitrides. In this study, we explore the growth and characterization of polarization-induced AlN/GaN heterostructures using plasma-assisted molecular beam epitaxy (PA-MBE) on AlN-on-sapphire templates. To improve the crystal quality and demonstrate the effectiveness of the PA-MBE approach, a thick AlN buffer of 180 nm was first grown on the AlN-on sapphire template. This buffer acts as a back-barrier to enhance the breakdown characteristic and isolate leakage paths that exist in the interface between the AlN epilayer and the AlN template. A root-mean-square roughness of 0.2 nm over a scanned area of 2×2 µm2 was measured by atomic force microscopy (AFM), and the full-width at half-maximum of (002) and (102) planes on the X-ray rocking curve was 101 and 206 arcsec, respectively, using by high-resolution X-ray diffraction (HR-XRD). The electron mobility of 443 cm2/Vs with a carrier concentration of 2.50×1013 cm-2 at room temperature was achieved in the AlN/GaN heterostructures by using a polarization-induced GaN channel. The low depletion capacitance of 15 pF is resolved by the capacitance-voltage. These results indicate that the polarization-induced AlN/GaN heterostructures have great potential for next-generation high-temperature, high-frequency, and high-power electronics.

Keywords: AlN, GaN, MBE, heterostructures

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Authors: Maulita Sari Hani, Abraham B. Sianipar, Abdi Hasan, Erfa Canistya, Ismail Alaydrus, Asril Djunaidi

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Whale shark tourism offer potential benefits to support economic alternative livelihood. Since 2017, Conservation International Indonesia worked in Sumbawa to monitor whale shark distribution and identified species aggregation in Teluk Saleh. We conducted a survey on May 23th-27th, 2018 and involved 86 local community from five hamlets in Labuan Jambu village. Furthermore, forum group discussion (FGD) held with 20 village representative on July 30th, 2018. The result of frequency distribution demonstrated 95% of respondents show positive perceptions towards sustainable development of whale shark tourism with 40% willing to participate in boat rental services. The community also proposes to participate in providing other tourism services including the local guide (12%), food and beverage or F&B (8%), local transport (8%), and homestay (6%). 34% of respondents agreed to establish a new institution (under village officials) to coordinate tourism services provided by the local community. We also conducted participatory mapping with 15 key informants where the result confirmed 13 areas of whale shark aggregation with all-year-round sightings. The FGD results in 20 participants ready to start the pilot project of community-based whale shark tourism in August 2018, including 4 boat rental (3 speedboats and 1 floating cage boat), 6 homestays, 4 car rentals, 1 F&B, 1 gear rental, 2 guides, and 2 local products. In addition, we facilitate village official in establishing policy and regulations for whale shark conservation and sustainable community-based tourism through village regulation, code of conduct, best practices, and capacity building program.

Keywords: marine wildlife tourism, elasmobranch, conservation, sustainable tourism, co-management

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Authors: Willian C. De Brito, Hernan D. C. Munoz, Erlan V. C. Carvalho, Helder L. C. De Oliveira

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In order to improve commute time for small distance trips and relieve large cities traffic, a new transport category has been the subject of research and new designs worldwide. The air taxi travel market promises to change the way people live and commute by using the concept of vehicles with the ability to take-off and land vertically and to provide passenger’s transport equivalent to a car, with mobility within large cities and between cities. Today’s civil air transport remains costly and accounts for 2% of the man-made CO₂ emissions. Taking advantage of this scenario, many companies have developed their own Vertical Take Off and Landing (VTOL) design, seeking to meet comfort, safety, low cost and flight time requirements in a sustainable way. Thus, the use of green power supplies, especially batteries, and fully electric power plants is the most common choice for these arising aircrafts. However, it is still a challenge finding a feasible way to handle with the use of batteries rather than conventional petroleum-based fuels. The batteries are heavy and have an energy density still below from those of gasoline, diesel or kerosene. Therefore, despite all the clear advantages, all electric aircrafts (AEA) still have low flight autonomy and high operational cost, since the batteries must be recharged or replaced. In this sense, this paper addresses a way to optimize the energy consumption in a typical mission of an aerial taxi aircraft. The approach and landing procedure was chosen to be the subject of an optimization genetic algorithm, while final programming can be adapted for take-off and flight level changes as well. A real tilt rotor aircraft with fully electric power plant data was used to fit the derived dynamic equations of motion. Although a tilt rotor design is used as a proof of concept, it is possible to change the optimization to be applied for other design concepts, even those with independent motors for hover and cruise flight phases. For a given trajectory, the best set of control variables are calculated to provide the time history response for aircraft´s attitude, rotors RPM and thrust direction (or vertical and horizontal thrust, for independent motors designs) that, if followed, results in the minimum electric power consumption through that landing path. Safety, comfort and design constraints are assumed to give representativeness to the solution. Results are highly dependent on these constraints. For the tested cases, performance improvement ranged from 5 to 10% changing initial airspeed, altitude, flight path angle, and attitude.

Keywords: air taxi travel, all electric aircraft, batteries, energy consumption, genetic algorithm, landing performance, optimization, performance improvement, tilt rotor, VTOL design

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Authors: Kita R. Ashman, Anthony R. Rendall, Matthew R. E. Symonds, Desley A. Whisson

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Forest cover is decreasing globally, chiefly due to the conversion of forest to agricultural landscapes. In contrast, the area under plantation forestry is increasing significantly. For wildlife occupying landscapes where native forest is the dominant land cover, plantations generally represent a lower value habitat; however, plantations established on land formerly used for pasture may benefit wildlife by providing temporary forest habitat and increasing connectivity. This study investigates the influence of landscape, site, and climatic factors on koala population density in far south-west Victoria where there has been extensive plantation establishment. We conducted koala surveys and habitat characteristic assessments at 72 sites across three habitat types: plantation, native vegetation blocks, and native vegetation strips. We employed a hierarchical modeling framework for estimating abundance and constructed candidate multinomial N-mixture models to identify factors influencing the abundance of koalas. We detected higher mean koala density in plantation sites (0.85 per ha) than in either native block (0.68 per ha) or native strip sites (0.66 per ha). We found five covariates of koala density and using these variables, we spatially modeled koala abundance and discuss factors that are key in determining large-scale distribution and density of koala populations. We provide a distribution map that can be used to identify high priority areas for population management as well as the habitat of high conservation significance for koalas. This information facilitates the linkage of ecological theory with the on-ground implementation of management actions and may guide conservation planning and resource management actions to consider overall landscape configuration as well as the spatial arrangement of plantations adjacent to the remnant forest.

Keywords: abundance modelling, arboreal mammals plantations, wildlife conservation

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Authors: Florian Misoc, Cyril Okhio, Joshua Tolbert, Nick Carlin, Thomas Ramey

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This project is focused on designing a Stirling engine system for a solar-thermal-electrical system that can supply electric power to a single residential unit. Since Stirling engines are heat engines operating any available heat source, is notable for its ability to generate clean and reliable energy without emissions. Due to the need of finding alternative energy sources, the Stirling engines are making a comeback with the recent technologies, which include thermal energy conservation during the heat transfer process. Recent reviews show mounting evidence and positive test results that Stirling engines are able to produce constant energy supply that ranges from 5kW to 20kW. Solar Power source is one of the many uses for Stirling engines. Using solar energy to operate Stirling engines is an idea considered by many researchers, due to the ease of adaptability of the Stirling engine. In this project, the Stirling engine developed was designed and tested to operate from biomass source of energy, i.e., wood pellets stove, during low solar radiation, with good results. A 20% efficiency of the engine was estimated, and 18% efficiency was measured, making it suitable and appropriate for residential applications. The effort reported was aimed at exploring parameters necessary to design, build and test a ‘Solar Powered Stirling Engine (SPSE)’ using Water (H₂O) as the Heat Transfer medium, with Nitrogen as the working gas that can reach or exceed an efficiency of 20%. The main objectives of this work consisted in: converting a V-twin cylinder air compressor into an alpha-type Stirling engine, construct a Solar Water Heater, by using an automotive radiator as the high-temperature reservoir for the Stirling engine, and an array of fixed mirrors that concentrate the solar radiation on the automotive radiator/high-temperature reservoir. The low-temperature reservoir is the surrounding air at ambient temperature. This work has determined that a low-cost system is sufficiently efficient and reliable. Off-the-shelf components have been used and estimates of the ability of the Engine final design to meet the electricity needs of small residence have been determined.

Keywords: stirling engine, solar-thermal, power inverter, alternator

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Authors: Fariba Ebrahimi, Mehdi Ghorbani, Ali Salajegheh

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Comprehensively water management considers economic, environmental, technical and social and also sustainability of water resources for future generations. Grassland management implies cooperative approach and involves all stakeholders and also introduces issues to managers, decision and policy makers. Solving these issues needs integrated and system approach. According to the recognition of actors or key persons in necessary to apply cooperative management of Water. Therefore, based on stakeholder analysis and social network analysis can be used to demonstrate the most effective actors for environmental decisions. In this research, social powers according are specified to social network approach at Water utilizers’ level of Natural in Jirood catchment of Latian basin. In this paper, utilizers of water resources were recognized using field trips and then, trust and collaboration matrix produced using questionnaires. In the next step, degree centrality index were Examined. Finally, geometric position of each actor was illustrated in the network. The results of the research based on centrality index have a key role in recognition of cooperative management of Water in Jirood and also will help managers and planners of water in the case of recognition of social powers in order to organization and implementation of sustainable management of Water.

Keywords: social network analysis, water co-management, social power, centrality index, local stakeholders network, Jirood catchment

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Authors: Ahmet Calik

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In present study, the effect of adherend geometry on the tensile strength of adhesively single lap aluminum structures joint, bonded was numerically studied using by three dimensional finite element model. Six joint model were investigated. Analyses were performed in ANSYS commercial software. The results shows that the adherends shape has the highest effect on peel and shear stresses.

Keywords: adhesive, adherend, single lap joints, finite element

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Authors: Aghaei Amirkhizi Navideh, Sadjadi Soodeh Sadat, Moghaddam Banaem Leila, Athari Allaf Mitra, Johari Daha Fariba

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Dendrimers are good candidates for preparing metal nanoparticles because they can structurally and chemically well-defined templates and robust stabilizers. Poly amidoamine (PAMAM) dendrimer-based multifunctional cancer therapeutic conjugates have been designed and synthesized in pharmaceutical industry. In addition, encapsulated nanoparticle surfaces are accessible to substrates so that catalytic reactions can be carried out. For preparation of dendimer-metal nanocomposite, a dendrimer solution containing an average of 55 Yb+3 ions per dendrimer was prepared. Prior to reduction, the pH of this solution was adjusted to 7.5 using NaOH. NaBH4 was used to reduce the dendrimer-encapsulated Yb+3 to the zerovalent metal. The pH of the resulting solution was then adjusted to 3, using HClO4, to decompose excess BH4-. The UV-Vis absorption spectra of the mixture were recorded to ensure the formation of Yb-G5-NH2 complex. High-resolution electron microscopy (HRTEM) and size distribution results provide additional information about dendimer-metal nanocomposite shape, size, and size distribution of the particles. The resulting mixture was irradiated in Tehran Research Reactor 2h and neutron fluxes were 3×1011 n/cm2.Sec and the specific activity was 7MBq. Radiochemical and chemical and radionuclide quality control testes were carried. Gamma Spectroscopy and High-performance Liquid Chromatography HPLC, Thin-Layer Chromatography TLC were recorded. The injection of resulting solution to solid tumor in mice shows that it could be resized the tumor. The studies about solid tumors and nano composites show that ytterbium encapsulated-dendrimer radiopharmaceutical could be introduced as a new therapeutic for the treatment of solid tumors.

Keywords: nano-radio pharmaceutical, ytterbium, PAMAM, dendrimers

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Authors: Vinod Kumar Gupta, Narendrakumar M. Chaudhari, Suchismitha Iskepalli, Chitra Dutta

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Background-The community composition of the human microbiome is known to vary at distinct anatomical niches. But little is known about the nature of variations if any, at the genome/sub-genome levels of a specific microbial community across different niches. The present report aims to explore, as a case study, the variations in gene repertoire of 28 Prevotella reference draft genomes derived from different body-sites of human, as reported earlier by the Human Microbiome Consortium. Results-The analysis reveals the exclusive presence of 11798, 3673, 3348 and 934 gene families and exclusive absence of 17, 221, 115 and 645 gene families in Prevotella genomes derived from the human oral cavity, gastro-intestinal tracts (GIT), urogenital tract (UGT) and skin, respectively. The pan-genome for Prevotella remains “open”. Distribution of various functional COG categories differs appreciably among the habitat-specific genes, within Prevotella pan-genome and between the GIT-derived Bacteroides and Prevotella. The skin and GIT isolates of Prevotella are enriched in singletons involved in Signal transduction mechanisms, while the UGT and oral isolates show higher representation of the Defense mechanisms category. No niche-specific variations could be observed in the distribution of KEGG pathways. Conclusion-Prevotella may have developed distinct genetic strategies for adaptation to different anatomical habitats through selective, niche-specific acquisition and elimination of suitable gene-families. In addition, individual microorganisms tend to develop their own distinctive adaptive stratagems through large repertoires of singletons. Such in situ, habitat-driven refurbishment of the genetic makeup can impart substantial intra-lineage genome diversity within the microbes without perturbing their general taxonomic heritage.

Keywords: body niche adaptation, human microbiome, pangenome, Prevotella

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Authors: Sherif D. El Wakil, John Rice

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The aim of the current work was to employ the finite element method to model a slab, with a small hole across its width, undergoing plastic plane strain deformation. The computational model had, however, to be validated by comparing its results with those obtained experimentally. Since they were in good agreement, the finite element method can therefore be considered a reliable tool that can help gain better understanding of the mechanism of ductile failure in structural members having stress raisers. The finite element software used was ANSYS, and the PLANE183 element was utilized. It is a higher order 2-D, 8-node or 6-node element with quadratic displacement behavior. A bilinear stress-strain relationship was used to define the material properties, with constants similar to those of the material used in the experimental study. The model was run for several tensile loads in order to observe the progression of the plastic deformation region, and the stress concentration factor was determined in each case. The experimental study involved employing the visioplasticity technique, where a circular mesh (each circle was 0.5 mm in diameter, with 0.05 mm line thickness) was initially printed on the side of an aluminum slab having a small hole across its width. Tensile loading was then applied to produce a small increment of plastic deformation. Circles in the plastic region became ellipses, where the directions of the principal strains and stresses coincided with the major and minor axes of the ellipses. Next, we were able to determine the directions of the maximum and minimum shear stresses at the center of each ellipse, and the slip-line field was then constructed. We were then able to determine the stress at any point in the plastic deformation zone, and hence the stress concentration factor. The experimental results were found to be in good agreement with the analytical ones.

Keywords: finite element method to model a slab, slab undergoing plastic deformation, stress distribution around a circular hole, visioplasticity

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Authors: Erika K. Méndez, Carlos E. Orrego, Diana L. Manrique, Juan D. Gonzalez, Doménica Vallejo

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High moisture content in fruits generates post-harvest problems such as mechanical, biochemical, microbial and physical losses. Dehydration, which is based on the reduction of water activity of the fruit, is a common option for overcoming such losses. However, regular hot air drying could affect negatively the quality properties of the fruit due to the long residence time at high temperature. Power ultrasound (US) application during the convective drying has been used as a novel method able to enhance drying rate and, consequently, to decrease drying time. In the present study, a new approach was tested to evaluate the effect of US on the drying time, the final antioxidant activity (AA) and the total polyphenol content (TPC) of banana slices (BS), mango slices (MS) and guava slices (GS). There were also studied the drying kinetics with nine different models from which water effective diffusivities (Deff) (with or without shrinkage corrections) were calculated. Compared with the corresponding control tests, US assisted drying for fruit slices showed reductions in drying time between 16.23 and 30.19%, 11.34 and 32.73%, and 19.25 and 47.51% for the MS, BS and GS respectively. Considering shrinkage effects, Deff calculated values ranged from 1.67*10-10 to 3.18*10-10 m2/s, 3.96*10-10 and 5.57*10-10 m2/s and 4.61*10-10 to 8.16*10-10 m2/s for the BS, MS and GS samples respectively. Reductions of TPC and AA (as DPPH) were observed compared with the original content in fresh fruit data in all kinds of drying assays.

Keywords: banana, drying, effective diffusivity, guava, mango, ultrasound

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Authors: Michal Urzynicok, Krzysztof Kwiecinski

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The development of materials used in the power generation industry for the production of boilers and their parts is characterized by high steam parameters, which present new challenges. Implementation of new combinations of alloying elements that lead to the best possible mechanical properties, including creep resistance, greatly affects new steels' weldability. All new grades have to undergo many different examinations, in regards to bending and welding, in order to enable the development of fabrication technologies, ensuring failure-free production and assembly of boiler components. 12% Cr martensitic steels like THOR™ 115 or VM-12 SHC are characterized by high oxidation resistance in high-temperature environments. At the moment, VM-12 SHC can be found in many boilers where both headers and superheater coils were produced. As this material is very difficult to obtain, a search for a proper replacement has begun. A new creep strength-enhanced ferritic steel for service in supercritical and ultra-supercritical boiler applications was developed by Tenaris in Italy and it is designated as Thor™115 (Tenaris High Oxidation Resistance). As high demand in power plants occurred to replace some parts of existing installations fabricated from VM12-SHC with other alternatives, a new development of welding procedures has begun to prepare fabricators for the challenges of joining old components with new THOR™ 115 material. This paper covers the first research of welding of dissimilar joints made out of VM12-SHC and THOR™ 115.

Keywords: thor, vm12, dissimilar welding, weldability

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Authors: Ebrahim Rahmani, Siyamak Moazeni

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According to the Iraq's first constitutional law (approved 2005), Iraq is an independent with sovereignty and its governmental structure is parliamentary democratic republic and federal. Even in reforms in 2009, this article of law did not changed at all. But considering the existence of this emphasis and clarity which is mentioned in the law, different and sometimes contradictory interpretations and positions are expressed about federalism in the way that we can say, considering the importance of the matter, federalism is a focus point to create and expansion of the cold war among leaders of different groups of the country. Iraq's today political and security position has granted the suitable opportunity to Iraq's Kurdistan in appearing of the recent security crisis to increase its share from the central political power or to achieve to its independent dream. The federalism the weakest point of Iraq's territorial integrity in a way that if different groups do not come to a consensus about it and do not think about a mechanism which is accepted by all of them, this can effect on and Iraq's political stability and security. Iraq's Kurdistan follows the option of disintegration and separation under the shadow of political and security changes, even with existence of some Iraqi groups' hopes regarding the improvement of situation after parliament election and also considering Masoud Barezani's power will for separation from Iraq as well as regarding special international changes and disintegration of Karime from Ukraine and ISIS crises; concerns have been created among regional and international powers and interior players. In this article, a paradox due constitutional law about federalism, Iraq's central government view and its politicians to the matter and the regional effect of this action on region's geopolitics are reviewed as well.

Keywords: constitutional law, federalism, decomposition, Iraq's Kurdistan

Procedia PDF Downloads 328