Search results for: Hamid Reza Naji
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 768

Search results for: Hamid Reza Naji

438 The Application of Polymers in Enhanced Oil Recovery: Recent Trends

Authors: Reza M. Rudd, Ali Saeedi, Colin Wood

Abstract:

In this article, the latest advancements made in the applications of polymers in the enhanced hydrocarbon recovery technologies are investigated. For this purpose, different classes of polymers are reviewed and the latest progresses made in making them suitable for application under harsh reservoir conditions are discussed. The main reservoir conditions whose effects are taken into account include the temperature, rock mineralogy and brine salinity and composition. For profile modification and blocking the thief zones, polymers are used in the form of nanocomposite hydrogels. Polymers are also used as thickeners during CO2 flooding. Also, they are used in enhanced gas recovery, to inhibit the mixing of injection gas with the in-situ natural gas. This review covers the main types of polymers, their functions and the challenges in their applications, some of which are mentioned above. Included in this review are also the latest progresses made in the development of new polymeric surfactants used for surfactant flooding.

Keywords: EOR, EGR, polymer flooding, profile modification, mobility control, nanocomposite hydrogels, CO2 flooding, polymeric surfactants

Procedia PDF Downloads 535
437 Integrating Deterministic and Probabilistic Safety Assessment to Decrease Risk & Energy Consumption in a Typical PWR

Authors: Ebrahim Ghanbari, Mohammad Reza Nematollahi

Abstract:

Integrating deterministic and probabilistic safety assessment (IDPSA) is one of the most commonly used issues in the field of safety analysis of power plant accident. It has also been recognized today that the role of human error in creating these accidents is not less than systemic errors, so the human interference and system errors in fault and event sequences are necessary. The integration of these analytical topics will be reflected in the frequency of core damage and also the study of the use of water resources in an accident such as the loss of all electrical power of the plant. In this regard, the SBO accident was simulated for the pressurized water reactor in the deterministic analysis issue, and by analyzing the operator's behavior in controlling the accident, the results of the combination of deterministic and probabilistic assessment were identified. The results showed that the best performance of the plant operator would reduce the risk of an accident by 10%, as well as a decrease of 6.82 liters/second of the water sources of the plant.

Keywords: IDPSA, human error, SBO, risk

Procedia PDF Downloads 103
436 Analysis of Cannabinol and Cannabidiol affinity with GBRA1

Authors: Hamid Hossein Khezri, Afsaneh Javdani-Mallak

Abstract:

Fast inhibitory neurotransmission in the mammalian nervous system is largely mediated by GABAA receptors, chloride-selective members of the superfamily of pentameric Cys-loop receptors. Cannabidiol (CBD) is one of the members of cannabinoid compounds found in cannabis. CBD and Cannabinol (CBN), as the other extract of plant Cannabis were able to reduce myofascial pain in rats with immunosuppressive and anti-inflammatory activities. In this study, we accomplished protein-protein BLAST, and the sequence was found to be for Gamma-aminobutyric acid receptor subunit alpha-1 (GBRA1) chain A and its 3D structure was subsequently downloaded from Protein Data Bank. The structures of the ligands, cannabinol, and cannabidiol, were obtained from PubChem. After the necessary process of the obtained files, AutoDock Vina was used to perform molecular docking. Docking between the ligands and GBRA1 chain A revealed that cannabinol has a higher affinity to GBRA1 (binding energy = -7.5 kcal/mol) compared to cannabidiol (binding energy = -6.5 kcal/mol). Furthermore, cannabinol seems to be able to interact with 10 residues of the protein, out of which 3 are in the neurotransmitter-gated ion-channel transmembrane domain of GBRA1, whereas cannabidiol interacts with two other residues. Although the results of this project do not indicate the activating /or inhibitory capability of the studied compounds, it suggests that cannabinol can act as a relatively strong ligand for GBRA1.

Keywords: protein-ligand docking, cannabinol, cannabidiol, GBRA1

Procedia PDF Downloads 72
435 Appropriate Legal System for Protection of Plant Innovations in Afghanistan

Authors: Mohammad Reza Fooladi

Abstract:

Because of the importance and effect of plant innovations on economy, industry, and especially agriculture, they have been on the core attention of legislators at the national level, and have been a topic of international documents related to intellectual innovations in the recent decades. For protection of plant innovations, two legal systems (i.e. particular system based on International Convention for protection of new variety of plants, and the patent system) have been considered. Ease of access to the support and the level of support in each of these systems are different. Our attempt in this paper, in addition to describing and analyzing the characteristics of each system, is to suggest the compatible system to the industry and agriculture of Afghanistan. Due to the lack of sufficient industrial infrastructure and academic research, the particular system based on the International Convention on the protection of new variety of plants is suggested. At the same time, appropriate industrial and legal infrastructures, as well as laboratories and research centers should be provided in order that plant innovations under the patent system could also be supported.

Keywords: new varieties of plant, patent, agriculture, Afghanistan

Procedia PDF Downloads 298
434 Monte Carlo Simulation of Pion Particles

Authors: Reza Reiazi

Abstract:

Attempts to verify Geant4 hadronic physic to transport antiproton beam using standard physics list have not reach to a reasonable results because of lack of reliable cross section data or non reliable model to predict the final states of annihilated particles. Since most of the antiproton annihilation energy is carried away by recoiling nuclear fragments which are result of pions interactions with surrounding nucleons, it should be investigated if the toolkit verified for pions. Geant4 version 9.4.6.p01 was used. Dose calculation was done using 700 MeV pions hitting a water tank applying standards physic lists. We conclude Geant4 standard physics lists to predict the depth dose of Pion minus beam is not same for all investigated models. Since the nuclear fragments will deposit their energy in a small distance, they are the most important source of dose deposition in the annihilation vertex of antiproton beams.

Keywords: Monte Carlo, Pion, simulation, antiproton beam

Procedia PDF Downloads 403
433 Effect of Accelerated Ions Interacted with Al Targets Using Plasma Focus Device

Authors: Morteza Habibi, Reza Amrollahi

Abstract:

The Aluminum made targets were placed at the central part of a Fillipov type (90KJ) plasma focus cathode. These targets were exposed to perpendicular dense plasma stream incidence. Melt layer erosion by melt motion, surface smoothing, and bubble formation were some of different effects caused by diverse working conditions. Micro hardness of surface layer tends to decrease particularly in the central region of the sample where destruction is more intense. The most pronouced melt motion is registered in the region of the maximum gradient of pressure and the etching of aluminium surface is noticeable in the central part of target. The crater with a maximum depth of 200µm, and the diameter of about 8.5mm is observed close to the mountains. Adding Krypton admixture to the Deuterium gas lead to collapsing bubbles and greater surface damage.

Keywords: fillipov type plasma focus, al target interaction, bubbling effect, melt layer motion, surface smoothing

Procedia PDF Downloads 501
432 Preparation of n-type Bi2Te3 Films by Electrophoretic Deposition

Authors: Tahereh Talebi, Reza Ghomashchi, Pejman Talemi, Sima Aminorroaya

Abstract:

A high quality crack-free film of Bi2Te3 material has been deposited for the first time using electrophoretic deposition (EPD) and microstructures of various films have been investigated. One of the most important thermoelectric (TE) applications is Bi2Te3 to manufacture TE generators (TEG) which can convert waste heat into electricity targeting the global warming issue. However, the high cost of the manufacturing process of TEGs keeps them expensive and out of reach for commercialization. Therefore, utilizing EPD as a simple and cost-effective method will open new opportunities for TEG’s commercialization. This method has been recently used for advanced materials such as microelectronics and has attracted a lot of attention from both scientists and industry. In this study, the effect of media of suspensions has been investigated on the quality of the deposited films as well as their microstructure. In summary, finding an appropriate suspension is a critical step for a successful EPD process and has an important effect on both the film’s quality and its future properties.

Keywords: Bi2Te3, electrical conductivity, electrophoretic deposition, thermoelectric materials, thick films

Procedia PDF Downloads 226
431 Law and its Implementation and Consequences in Pakistan

Authors: Amir Shafiq, Asif Shahzad, Shabbar Mehmood, Muhammad Saeed, Hamid Mustafa

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Legislation includes the law or the statutes which is being reputable by a sovereign authority and generally can be implemented by the courts of law time to time to accomplish the objectives. Historically speaking upon the emergence of Pakistan in 1947, the intact laws of the British Raj remained effective after ablution by Islamic Ideology. Thus, there was an intention to begin the statutes book afresh for Pakistan's legal history. In consequence thereof, the process of developing detailed plans, procedures and mechanisms to ensure legislative and regulatory requirements are achieved began keeping in view the cultural values and the local customs. This article is an input to the enduring discussion about implementing rule of law in Pakistan whereas; the rule of law requires the harmony of laws which is mostly in the arrangement of codified state laws. Pakistan has legal plural civilizations where completely different and independent systems of law like the Mohammadan law, the state law and the traditional law exist. The prevailing practiced law in Pakistan is actually the traditional law though the said law is not acknowledged by the State. This caused the main problem of the rule of law in the difference between the state laws and the cultural values. These values, customs and so-called traditional laws are the main obstacle to enforce the State law in true letter and spirit which has caused dissatisfaction of the masses and distrust upon the judicial system of the country.

Keywords: consequences, implement, law, Pakistan

Procedia PDF Downloads 405
430 Impact of Maternal Nationality on Caesarean Section Rate Variation in a High-income Country

Authors: Saheed Shittu, Lolwa Alansari, Fahed Nattouf, Tawa Olukade, Naji Abdallah, Tamara Alshdafat, Sarra Amdouni

Abstract:

Cesarean sections (CS), a highly regarded surgical intervention for improving fetal-maternal outcomes and serving as an integral part of emergency obstetric services, are not without complications. Although CS has many advantages, it poses significant risks to both mother and child and increases healthcare expenditures in the long run. The escalating global prevalence of CS, coupled with variations in rates among immigrant populations, has prompted an inquiry into the correlation between CS rates and the nationalities of women undergoing deliveries at Al-Wakra Hospital (AWH), Qatar's second-largest public maternity hospital. This inquiry is motivated by the notable CS rate of 36%, deemed high in comparison to the 34% recorded across other Hamad Medical Corporation (HMC) maternity divisions This is Qatar's first comprehensive investigation of Caesarean section rates and nationalities. A retrospective cross-sectional study was conducted, and data for all births delivered in 2019 were retrieved from the hospital's electronic medical records. The CS rate, the crude rate, and adjusted risks of Caesarean delivery for mothers from each nationality were determined. The common indications for CS were analysed based on nationality. The association between nationality and Caesarean rates was examined using binomial logistic regression analysis considering Qatari women as a standard reference group. The correlation between the CS rate in the country of nationality and the observed CS rate in Qatar was also examined using Pearson's correlation. This study included 4,816 births from 69 different nationalities. CS was performed in 1767 women, equating to 36.5%. The nationalities with the highest CS rates were Egyptian (49.6%), Lebanese (45.5%), Filipino and Indian (both 42.2%). Qatari women recorded a CS rate of 33.4%. The major indication for elective CS was previous multiple CS (39.9%) and one prior CS, where the patient declined vaginal birth after the cesarean (VBAC) option (26.8%). A distinct pattern was noticed: elective CS was predominantly performed on Arab women, whereas emergency CS was common among women of Asian and Sub-Saharan African nationalities. Moreover, a significant correlation was found between the CS rates in Qatar and the women's countries of origin. Also, a high CS rate was linked to instances of previous CS. As a result of these insights, strategic interventions were successfully implemented at the facility to mitigate unwarranted CS, resulting in a notable reduction in CS rate from 36.5% in 2019 to 34% in 2022. This proves the efficacy of the meticulously researched approach. The focus has now shifted to reducing primary CS rates and facilitating well-informed decisions regarding childbirth methods.

Keywords: maternal nationality, caesarean section rate variation, migrants, high-income country

Procedia PDF Downloads 37
429 Key Factors of Success and Deterrent of IT Projects, Case study: Islamic Azad University, Zahedan Branch

Authors: Mohammad Reza Abidi, Zahra Nourouz Pour, Mehdi Moudi

Abstract:

In this research, firstly critical success factors and deterrent factors in implementing projects and also the factors those cause information technology productivity (IT) paradox in Islamic Azad University, Zahedan branch examined. Research method of this paper is descriptive. In fact, the researcher by using survey, proposed useful solutions. In this research, subjects’ responders to questionnaires items were based on Likert scale. In the questionnaire, economic, technical, organizational and cultural factors in the university have been assessed in order to obtain the necessary validity. We used masters and technicians of IT department’s advices to realize reliability and consistency. For the reliability test we used Cronbach’s reliability test and validity has been obtained using SPSS software. Because of the research questions and objectives, t-student test is used for hypothesis testing. Finally we analyze the findings, we offer conclusions and suggestions.

Keywords: IT projects, Islamic Azad University, success factors, deterrent factors

Procedia PDF Downloads 280
428 Degree of Bending in Axially Loaded Tubular KT-Joints of Offshore Structures: Parametric Study and Formulation

Authors: Hamid Ahmadi, Shadi Asoodeh

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The fatigue life of tubular joints commonly found in offshore industry is not only dependent on the value of hot-spot stress (HSS), but is also significantly influenced by the through-the-thickness stress distribution characterized by the degree of bending (DoB). The determination of DoB values in a tubular joint is essential for improving the accuracy of fatigue life estimation using the stress-life (S–N) method and particularly for predicting the fatigue crack growth based on the fracture mechanics (FM) approach. In the present paper, data extracted from finite element (FE) analyses of tubular KT-joints, verified against experimental data and parametric equations, was used to investigate the effects of geometrical parameters on DoB values at the crown 0˚, saddle, and crown 180˚ positions along the weld toe of central brace in tubular KT-joints subjected to axial loading. Parametric study was followed by a set of nonlinear regression analyses to derive DoB parametric formulas for the fatigue analysis of KT-joints under axial loads. The tubular KT-joint is a quite common joint type found in steel offshore structures. However, despite the crucial role of the DoB in evaluating the fatigue performance of tubular joints, this paper is the first attempt to study and formulate the DoB values in KT-joints.

Keywords: tubular KT-joint, fatigue, degree of bending (DoB), axial loading, parametric formula

Procedia PDF Downloads 335
427 Essential Oil Compounds and Antioxidant Activity for α-Thujene Rich Two Species of Artemisia

Authors: Reza Dehghani Bidgoli

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Although Artemisia species are one of the most important medicinal plants, there are a few reports on chemistry or activity of their essential oils because of low amounts of the oils in this genus. In this study, chemical composition of essential oils leaves and stems of Artemisia sieberi and Artemisia aucheri growing wild in Kashan rangelands, central Iran, have been analyzed using GC–MS technique. Analysis revealed 50 identified compounds, representing 96.55% of the oil and 23 identified compounds representing 97.83% of the oil on Artemisia sieberi and Artemisia aucheri respectively. The yield of essential oil extraction is very higher than those of previous reports. In both plants α-thujene is the main component in both of them, with an extra value, 74.42%, in aucheri species. Several compounds (some with significant compositions), were found in these varieties of Artemisia which are not recorded in previous literature. Antioxidant activities of the essential oils were evaluated for the first time in this research work using β-carotene/linoleic acid assay and found to be surprisingly attributed directly to α-pinene contents in them.

Keywords: essential oil, artemisia aucheri, artemisia sieberi, α-thujene, antioxidant activity

Procedia PDF Downloads 416
426 Compressive Response of Unidirectional Basalt Fiber/Epoxy/MWCNTs Composites

Authors: Reza Eslami-Farsani, Hamed Khosravi

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The aim of this work is to study the influence of multi-walled carbon nanotubes (MWCNTs) addition at various contents with respect to the matrix (0-0.5 wt.% at a step of 0.1 wt.%) on the compressive response of unidirectional basalt fiber (UD-BF)/epoxy composites. Toward this end, MWCNTs were firstly functionalized with 3-glycidoxypropyltrimethoxysilane (3-GPTMS) to improve their dispersion state and interfacial compatibility with the epoxy. Subsequently, UD-BF/epoxy and multiscale 3-GPTMS-MWCNTs/UD-BF/epoxy composites were prepared. The mechanical properties of the composites were determined by quasi-static compression test. The compressive strength of the composites was obtained through performing the compression test on the off-axis specimens and extracting their longitudinal compressive strength. Results demonstrated that the highest value in compressive strength was attained at 0.4 wt.% MWCNTs with 41% increase, compared to the BF/epoxy composite. Potential mechanisms behind these were implied.

Keywords: multiscale polymeric composites, unidirectional basalt fibers, multi-walled carbon nanotubes, surface modification, compressive properties

Procedia PDF Downloads 273
425 Effect of Chemical, Organic and Biological Nitrogen on Yield and Yield Components of Soybean Cultivars

Authors: Hamid Hatami

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This experiment was included two cultivars i.e. Habbit and L17 (Main factor) with six fertilizer treatments i.e. control, seed inoculated with rhyzobium, base nitrogen + top-dress urea at R2 stage, base nitrogen + seed inoculated with rhyzobium + top-dress nitrogen at R2 stage, seed treated with humax + top-dress humax at R2 stage, base nitrogen + seed treated with humax + top-dress humax at R2 stage (sub factors ), as split-plot on the basis of RCBD with 3 replications at 2014. Treatment fertilizer of base nitrogen + seed treated with humax + top- dress humax at R2 stage and base nitrogen + top-dress urea in R2 stage had a significant superiority than the other fertilizer treatment in biological yield. L17 and Habbit with base nitrogen + seed treated with humax + top-dress humax in R2 stage and yield economical 5600 and 5767 kg/ha respectively, showed the most economical yield and Habbit cultivar with control and economical yield 3085 kg/ha showed the least economical yield among all the treatments. Results showed that fertilizer treatment of base nitrogen + seed treated with humax + top-dress humax in R2 stage and Habbit variety were suitable in this study.

Keywords: soybean, humax, rhyzobium, habbit

Procedia PDF Downloads 420
424 The Effect of Culture on User Interface Design of Social Media- A Case Study on Preferences of Saudi Arabian on the Arabic User Interface of Facebook

Authors: Hana Almakky, Reza Sahandi, Jacqui Taylor

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Social media continue to grow, and user interfaces may become more appealing if cultural characteristics are incorporated into their design. Facebook was designed in the west, and the original language was English. Subsequently, the words in the user interface were translated to other languages, including Arabic. Arabic words are written from right to left, and English is written from left to right. The translated version may misrepresent the original design and users preferences may influence their culture, which should be considered in the user interface design. Previous research indicates that users are more comfortable when interacting with a user interface, which relates to their own culture. Therefore, this paper, using a survey investigates the preferences of Saudi Arabian on the Arabic version of user interface of Facebook.

Keywords: culture, social media, user interface design, Facebook, Saudi Arabia

Procedia PDF Downloads 366
423 The Role of Information Technology in the Supply Chain Management

Authors: Azar Alizadeh, Mohammad Reza Naserkhaki

Abstract:

The application of the IT systems for collecting and analyzing the data can have a significant effect on the performance of any company. In recent decade, different advancements and achievements in the field of information technology have changed the industry compared to the previous decade. The adoption and application of the information technology are one of the ways to achieve a distinctive competitive personality to the companies and their supply chain. The acceptance of the IT and its proper implementation cam reinforce and improve the cooperation between different parts of the supply chain by rapid transfer and distribution of the precise information and the application of the informational systems, leading to the increase in the supply chain efficiency. The main objective of this research is to study the effects and applications of the information technology on and in the supply chain management and to introduce the effective factors on the acceptance of information technology in the companies. Moreover, in order to understand the subject, we will investigate the role and importance of the information and electronic commerce in the supply chain and the characteristics of the supply chain based on the information flow approach.

Keywords: electronic commerce, industry, information technology, management, supply chain, system

Procedia PDF Downloads 453
422 Numerical Analysis of Jet Grouting Strengthened Pile under Lateral Loading

Authors: Reza Ziaie Moayed, Naeem Gholampoor

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Jet grouting strengthened pile (JPP) is one of composite piles used in soft ground improvement. It may improve the vertical and lateral bearing capacity effectively and it has been practically used in a considerable scale. In order to make a further research on load transfer mechanism of single JPP with and without cap under lateral loads, JPP is analyzed by means of FEM analysis. It is resulted that the JPP pile could improve lateral bearing capacity by compared with bored concrete pile which is higher for shorter pile and the biggest bending moment of JPP pile is located in the depth of around 48% of embedded length of the pile. Meanwhile, increase of JPP pile length causes to increase of peak mobilized bending moment. Also, by cap addition, JPP piles will have a much higher lateral bearing capacity and increasing in cohesion of soil layer resulted to increase of lateral bearing capacity of JPP pile. In addition, the numerical results basically coincide with the experimental results presented by other researchers.

Keywords: bending moment, FEM analysis, JPP pile, lateral bearing capacity

Procedia PDF Downloads 293
421 An Energy Efficient Clustering Approach for Underwater ‎Wireless Sensor Networks

Authors: Mohammad Reza Taherkhani‎

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Wireless sensor networks that are used to monitor a special environment, are formed from a large number of sensor nodes. The role of these sensors is to sense special parameters from ambient and to make a connection. In these networks, the most important challenge is the management of energy usage. Clustering is one of the methods that are broadly used to face this challenge. In this paper, a distributed clustering protocol based on learning automata is proposed for underwater wireless sensor networks. The proposed algorithm that is called LA-Clustering forms clusters in the same energy level, based on the energy level of nodes and the connection radius regardless of size and the structure of sensor network. The proposed approach is simulated and is compared with some other protocols with considering some metrics such as network lifetime, number of alive nodes, and number of transmitted data. The simulation results demonstrate the efficiency of the proposed approach.

Keywords: underwater sensor networks, clustering, learning automata, energy consumption

Procedia PDF Downloads 335
420 Analysis of Cannabinoid and Cannabidiol Affinity with GABRA1

Authors: Hamid Hossein Khezri, Afsaneh Javdani-Mallak

Abstract:

Fast inhibitory neurotransmission in the mammalian nervous system is largely mediated by GABAA receptors, chloride-selective members of the superfamily of pentameric Cys-loop receptors. Cannabidiol (CBD) is one of the members of cannabinoid compounds found in cannabis. CBD and Cannabinol (CBN), as the other extract of plant Cannabis, were able to reduce myofascial pain in rats with immunosuppressive and anti-inflammatory activities. In this study, we accomplished protein-protein BLAST and the sequence was found to be for Gamma-aminobutyric acid receptor subunit alpha-1 (GBRA1) chain A and its 3D structure was subsequently downloaded from Protein Data Bank. The structures of the ligands cannabinol and cannabidiol were obtained from PubChem. After a necessary process of the obtained files, AutoDock Vina was used to performing molecular docking. Docking between the ligands and GBRA1 chain A revealed that cannabinol has a higher affinity to GBRA1 (binding energy = -7.5 kcal/mol) compared to cannabidiol (binding energy = -6.5 kcal/mol). Furthermore, cannabinol seems to be able to interact with 10 residues of the protein, out of which 3 are in the neurotransmitter-gated ion-channel transmembrane domain of GBRA1, whereas cannabidiol interacts with two other residues. Although the results of this project do not indicate the activating /or inhibitory capability of the studied compounds, it suggests that cannabinol can act as a relatively strong ligand for GBRA1.

Keywords: protein-ligand docking, cannabinol, cannabidiol, GBRA1

Procedia PDF Downloads 93
419 Study of Nanocrystalline Al Doped Zns Thin Films by Chemical Bath Deposition Method

Authors: Hamid Merzouk, Djahida Touati-Talantikite, Amina Zaabar

Abstract:

New nanosized materials are in huge expansion worldwide. They play a fundamental role in various industrial applications thanks their unique and functional properties. Moreover, in recent years, a great effort has been made to the design and control fabrication of nanostructured semiconductors such zinc sulphide. In recent years, much attention has been accorded in doped and co-doped ZnS to improve the ZnS films quality. We present in this work the preparation and characterization of ZnS and Al doped ZnS thin films. Nanoparticles ZnS and Al doped ZnS films are prepared by chemical bath deposition method (CBD), for various dopant concentrations. Thin films are deposed onto commercial microscope glass slides substrates. Thiourea is used as sulfide ion source, zinc acetate as zinc ion source and manganese acetate as manganese ion source in alkaline bath at 90 °C. X-ray diffraction (XRD) analyses are carried out at room temperature on films and powders with a powder diffractometer, using CuKα radiation. The average grain size obtained from the Debye–Scherrer’s formula is around 10 nm. Films morphology is examined by scanning electron microscopy. IR spectra of representative sample are recorded with the FTIR between 400 and 4000 cm-1.The transmittance (70 %) is performed with the UV–VIS spectrometer in the wavelength range 200–800 nm. This value is enhanced by Al doping.

Keywords: ZnS, nanostructured semiconductors, thin films, chemical bath deposition

Procedia PDF Downloads 496
418 Reliability Analysis of Steel Columns under Buckling Load in Second-Order Theory

Authors: Hamed Abshari, M. Reza Emami Azadi, Madjid Sadegh Azar

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For studying the overall instability of members of steel structures, there are several methods in which overall buckling and geometrical imperfection effects are considered in analysis. In first section, these methods are compared and ability of software to apply these methods is studied. Buckling loads determined from theoretical methods and software is compared for 2D one bay, one and two stories steel frames. To consider actual condition, buckling loads of three steel frames that have various dimensions are calculated and compared. Also, uncertainties that exist in loading and modeling of structures such as geometrical imperfection, yield stress, and modulus of elasticity in buckling load of 2D framed steel structures have been studied. By performing these uncertainties to each reliability analysis procedures (first-order, second-order, and simulation methods of reliability), one index of reliability from each procedure is determined. These values are studied and compared.

Keywords: buckling, second-order theory, reliability index, steel columns

Procedia PDF Downloads 467
417 Biomimetic to Architectural Design for Increased Sustainability

Authors: Hamid Yazdani, Fatemeh Abbasi

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Biomimicry, where flora, fauna or entire ecosystems are emulated as a basis for design, is a growing area of research in the fields of architecture and engineering. This is due to both the fact that it is an inspirational source of possible new innovation and because of the potential it offers as a way to create a more sustainable and even regenerative built environment. The widespread and practical application of biomimicry as a design method remains however largely unrealised. A growing body of international research identifies various obstacles to the employment of biomimicry as an architectural design method. One barrier of particular note is the lack of a clear definition of the various approaches to biomimicry that designers can initially employ. Through a comparative literature review, and an examination of existing biomimetic technologies, this paper elaborates on distinct approaches to biomimetic design that have evolved. A framework for understanding the various forms of biomimicry has been developed, and is used to discuss the distinct advantages and disadvantages inherent in each as a design methodology. It is shown that these varied approaches may lead to different outcomes in terms of overall sustainability or regenerative potential. It is posited that a biomimetic approach to architectural design that incorporates an understanding of ecosystems could become a vehicle for creating a built environment that goes beyond simply sustaining current conditions to a restorative practice where the built environment becomes a vital component in the integration with and regeneration of natural ecosystems.

Keywords: biomimicry, bio-inspired design, ecology, ecomimicry, industrial ecology

Procedia PDF Downloads 472
416 Overview on Effectiveness of Learning Contract in Architecture Design Studios

Authors: Badiossadat Hassanpour, Reza Sirjani, Nangkuala Utaberta

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The avant-garde educational systems are striving to find a life long learning methods. Different fields and majors have test variety of proposed models, and found their difficulties and strengths. Architecture as a critical stage of education due to its characteristics which are learning by doing and critique based education and evaluation is out of this study procedure. Learning contracts is a new alternative form of evaluation of students’ achievements, while it acts as agreement about learning goals. Obtained results from studies in different fields which confirm its positive impact on students' learning in those fields and positively affected students' motivation and confidence in meeting their own learning needs, prompted us to implement this model in architecture design studio. In this implemented contract to the studio, students were asked to use the existing possibility of contract to have self assessment and examine their professional development to identify whether they are deficient or they would like to develop more expertise. The evidences of this research as well indicate that students feel positive about the learning contract and see it accommodating their individual learning needs.

Keywords: contract (LC), architecture design studio, education, student-centered learning

Procedia PDF Downloads 409
415 A Study of Cracking Behavior in Concrete Beams Reinforced With Two Different Grades of Steel

Authors: Nihal Abdel Hamid Taha

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Crack evaluation of flexure reinforced concrete (RC) member is considered an important step in the design process, since the formation of concrete cracks depends on the possibility of exposure to various conditions(pollution, humidity,..etc.). Because of the disparity between different grades of steel in the service load stresses, this affects the cracking behavior. This paper is concerned with the crack pattern and cracking load for concrete beams with T-section reinforced with two different grades of steel at the service load levels stages up to ultimate load. A practical program has been put up to investigate the difference between reinforced steel bars with yield strength 420 N/mm2 and 500 N/mm2 through six T-section reinforced beams. The beams were tested under static- monotonic two– point service loading up to ultimate failure under flexural stresses. The influence of parameters such as clear concrete cover and concrete compressive strength are considered for each of the two grades of steel used. Cracking load, spacing and width were determined. The experimental results demonstrated that increasing the concrete strength results in both of cracking and ultimate load increase, while no significant difference in yield load for the two steel grades used. It has also become obvious, that the number of cracks was more for the lower steel strength, which is followed by decrease in crack width and spacing.

Keywords: RC beams, cracking behavior, steel stress, crack width, crack spacing

Procedia PDF Downloads 32
414 Second Order MIMO Sliding Mode Controller for Nonlinear Modeled Wind Turbine

Authors: Alireza Toloei, Ahmad R. Saffary, Reza Ghasemi

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Due to the growing need for energy and limited fossil resources, the use of renewable energy, particularly wind is strongly favored. We all wind energy can’t be saved. Betz law, 59% of the total kinetic energy of the wind turbine is extracting. Therefore turbine control to achieve maximum performance and maintain stable conditions seem necessary. In this article, we plan for a horizontal axis wind turbine variable-speed variable-pitch nonlinear controller to obtain maximum output power. The model presented in this article, including a wide range of wind turbines are horizontal axis. However, the parameters used in this model is from Vestas V29 225 kW wind turbine. We designed second order sliding mode controller, which was robust in the face of changes in wind speed and it eliminated chattering by using of super twisting algorithm. Finally, using MATLAB software to simulate the results we considered the accuracy of the simulation results.

Keywords: non linear controller, robust, sliding mode, kinetic energy

Procedia PDF Downloads 471
413 A New Sign Subband Adaptive Filter Based on Dynamic Selection of Subbands

Authors: Mohammad Shams Esfand Abadi, Mehrdad Zalaghi, Reza ebrahimpour

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In this paper, we propose a sign adaptive filter algorithm with the ability of dynamic selection of subband filters which leads to low computational complexity compared with conventional sign subband adaptive filter (SSAF) algorithm. Dynamic selection criterion is based on largest reduction of the mean square deviation at each adaption. We demonstrate that this simple proposed algorithm has the same performance of the conventional SSAF and somewhat faster than it. In the presence of impulsive interferences robustness of the simple proposed algorithm as well as the conventional SSAF and outperform the conventional normalized subband adaptive filter (NSAF) algorithm. Therefore, it is preferred for environments under impulsive interferences. Simulation results are presented to verify these above considerations very well have been achieved.

Keywords: acoustic echo cancellation (AEC), normalized subband adaptive filter (NSAF), dynamic selection subband adaptive filter (DS-NSAF), sign subband adaptive filter (SSAF), impulsive noise, robust filtering

Procedia PDF Downloads 569
412 Developing a HSE-Finacial Indicator Model in Oil Industry

Authors: Reza Safari, Ali Rajabzadeh Ghatari, Raheleh Hossseinzadeh Mahabadi

Abstract:

In the present world, there are different pressures on firms such as competition, legislations, social etc. these pressures force the firms to follow “survival” as their primary goal and then growth. One of the main factors that helps firms to reach their goals is proper financial performance. To find out about the financial performance, a firm should monitors its financial performance. Financial performance affected by many factors. This research seeks to clear which financial performance indicators are most important according to Environmental situation of a firm and what are their priorities. To do so, environmental indicators specified as presented on OECD Key Environmental Indicators 2008 and so the financial performance indicators such as Profitability, Liquidity, Gearing, Investor ratios, and etc. At this stage, the affections questioned through questionnaires. After gaining the results, data analyzed using Promethee technique. By using decision matrixes extracted from those techniques an expert system designed. This expert system suggests the suitable financial performance indicators and their ranking by receiving the environment situation given environment indicators weight.

Keywords: environment indicators, financial performance indicators, promethee, expert system

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411 Tree Species Classification Using Effective Features of Polarimetric SAR and Hyperspectral Images

Authors: Milad Vahidi, Mahmod R. Sahebi, Mehrnoosh Omati, Reza Mohammadi

Abstract:

Forest management organizations need information to perform their work effectively. Remote sensing is an effective method to acquire information from the Earth. Two datasets of remote sensing images were used to classify forested regions. Firstly, all of extractable features from hyperspectral and PolSAR images were extracted. The optical features were spectral indexes related to the chemical, water contents, structural indexes, effective bands and absorption features. Also, PolSAR features were the original data, target decomposition components, and SAR discriminators features. Secondly, the particle swarm optimization (PSO) and the genetic algorithms (GA) were applied to select optimization features. Furthermore, the support vector machine (SVM) classifier was used to classify the image. The results showed that the combination of PSO and SVM had higher overall accuracy than the other cases. This combination provided overall accuracy about 90.56%. The effective features were the spectral index, the bands in shortwave infrared (SWIR) and the visible ranges and certain PolSAR features.

Keywords: hyperspectral, PolSAR, feature selection, SVM

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410 Evaluating the Fire Resistance of Offshore Tubular K-Joints Subjected to Balanced Axial Loads

Authors: Neda Azari Dodaran, Hamid Ahmadi

Abstract:

Results of 405 finite element (FE) analyses were used in the present research to study the effect of the joint geometry on the ultimate strength and initial stiffness of tubular K-joints subjected to axial loading at fire-induced elevated temperatures. The FE models were validated against the data available from experimental tests. Structural behavior under different temperatures (200ºC, 400ºC, 500ºC, and 700ºC) was investigated and compared to the behavior at ambient temperature (20ºC). A parametric study was conducted to investigate the effect of dimensionless geometrical parameters (β, γ, θ, and τ) on the ultimate strength and initial stiffness. Afterwards, ultimate strength data extracted from the FE analyses were compared with the values calculated from the equations proposed by available design codes in which the ultimate strength of the joint at elevated temperatures is obtained by replacing the yield stress of the steel at ambient temperature with the corresponding value at elevated temperature. It was indicated that this method may not have acceptable accuracy for K-joints under axial loading. Hence, a design formula was developed, through nonlinear regression analyses, to determine the ultimate strength of K-joints subjected to balanced axial loads at elevated temperatures.

Keywords: axial loading, elevated temperature, parametric equation, static strength, tubular K-joint

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409 Effect of Elastic Modulus Anisotropy on Helical Piles Behavior in Sandy Soil

Authors: Reza Ziaie Moayed, Javad Shamsi Soosahab

Abstract:

Helical piles are being used extensively in engineering applications all over the world. There are insufficient studies on the helical piles' behavior in anisotropic soils. In this paper, numerical modeling was adopted to investigate the effect of elastic modulus anisotropy on helical pile behavior resting on anisotropic sand by using a finite element limit analysis. The load-displacement behavior of helical piles under compression and tension loads is investigated in different relative densities of soils, and the effect of the ratio of horizontal elastic modulus with respect to vertical elastic modulus (EH/EV) is evaluated. The obtained results illustrate that in sandy soils, the anisotropic ratio of elastic modulus (EH/EV) has notable effect on bearing capacity of helical piles in different relative density. Therefore, it may be recommended that the effect of anisotropic condition of soil elastic modulus should be considered in helical piles behavior.

Keywords: helical piles, bearing capacity, numerical modeling, soil anisotropy

Procedia PDF Downloads 129