Thermodynamic and Numerical Analysis of Tangentially Fired Boiler for Increasing Efficiency and Reducing Environmental Pollution

The evaluation of heat transfer and fluid mechanics mechanisms to increase the thermal efficiency and combustion quality in heavy industries, such as power plants, are important and significant issues in the field of engineering sciences, which can lead to significant advances. In this regard, the present paper has been developed with thermodynamic and numerical simulations of the MONTAZER GHAEM Power Plant boiler to study the increase in efficiency and reduce environmental pollution. Also in this research, the results of practical tests have been used to verify the simulations. The thermodynamic simulation results show that the required fuel consumption of the burners in current operating conditions is not 9.1 kg/s, but it is 8.1 kg/s. The low efficiency of the set, which leads to the injection of more than the required amount of fuel to the boiler, cause the non-corresponding power generation for injected fuel, which results in the reduction of the plant thermal efficiency from 36.4% to 33.9%. The results of computational fluid dynamics show that the lightness of natural gas combustion products and, the no-flow accumulation in the lower parts of the furnace, reduce the produced steam, which results in power loss at the exit. Numerical results also show that the highest rate of NOX production occurs near the burners due to the high flame temperature and high oxygen mass fraction and consequently, the non-uniform distribution of heat in the furnace

Study on the sustainability of FPC produced from Kilka (Clupeonella engrauliformis, C. grimmi and C. cultriventris) in two vacuum packaging and modified atmosphere packaging at different environmental factors

Fish protein concentrate (FPC) is a healthy, sustainable and high nutritive product which sanitized produced from fishes in which, protein and other nutrients are more concentrated than in fresh fishes. The aim of this research is to study on the sustainability of FPC produced from Kilka (Clupeonella engrauliformis , C. grimmi and C. cultriventris) in two Vaccum Packaging and Modified Atmosphere Packaging at different environmental factors during six months. In our study the analysis of FPC protein showed 91.2%, lipid: 0.5%, ash: 3.6%, moisture: 2.3%, Total Volatile Nitrogen: 10 ml/100gr and peroxide: 5meq/kg. Amino acids and fatty acids were also determined. Bacteria and Fungi were lower than 1000 colony. Samples are kept in different condition of temperature (5, 20 and 35 degree centigrade), humidity (25, 40 and 90 percent) and light and dark environment in six month. Lipid rate in FPC after 6 months in VP and MAP (60% C02, 30 % N2 and 10% O2), packages was decreased but was not significant (P>0.05). It was also detected that increase temperature lead to more decrease in lipid content. Protein rate of FPC was decreased from 91.2% to 73.6% during six months at 35°C in VP Package and from 91.2% to 69.4% in MAP package. These changes were significant (P<0.05). TVN and PV rate in FPC after 6 months in VP and MAP packages was increased but was significant (P<0.05). Amino acids and fatty acids were also determined. But more changes in MAP packages was detected

Adaptation of Line Operations Safety Audit (LOSA) to Dispatch Operations (DOSA)

Purpose: Dispatch Operations Safety Audit (DOSA) is a proactive and predictive method in safety management system that detects the capabilities and pitfalls of dispatcher performance. In this study, Dispatch-Line Operations Safety Audit is carried out in an airline and results are analyzed and discussed. Design/methodology: The method of DOSA implementation for flight operations officers is similar to LOSA for flight crew. Findings: Results show that DOSA has an important effect on Threat and Error Management (TEM) in the Operations Control Center (OCC). Originality/value: Potential applications of this research include the better threat and error management in OCC with the implementation of DOSA as well as identification of threats and errors types for FOOs in OCC. Also, distribution of threats and errors in different phases of dispatch shift is discussed, therefore syllabuses of training courses can be provided with respect to threat and error types for flight operations officers.Peer Reviewe

Protein and lipid changes of FPC produced from Caspian Sea kilkas in VP and MAP during storage at different temperatures

Fish Protein Concentrate (FPC) is a healthy, sustainable and high nutritive product that produced from fish and protein and other nutrients are more concentrated than in the fresh fish. The aim of this research is to study the sustainability of FPC produced from Kilka (combination of three Caspian Sea Kilka species, Clupeonella engrauliformis, C. grimmi and C. cultriventris which were not identified and processed separately) in VP (Vacuum Packaging) and MAP (Modified Atmosphere Packaging) at different temperatures during six months of storage. According to result of chemical analysis performed, protein content was evaluated 91.2%, lipid 0.5%, ash 3.6%, moisture 2.3%, TVN 10 mg/100g and peroxide 5 meq/kg in the produced FPC before packing. Amino acids and fatty acids were also determined. Lipid amount in FPC after 6 months at 35°C in VP changed from 0.50 to 0.45 and in MAP (combined of 60% CO2, 30% N2 and 10% O2), decreased from 0.50 to 0.36. It was also detected that increase in temperature leads to more decrease in lipid content but it was not significant (P>0.05). Protein content of FPC has changed from 91.2% to 73.6% during six months at 35°C in VP and 69.4% in MAP. But at 5°C, protein contents were changed from 91.2% to 88.4% and 81.2% in VP and MAP, respectively; these changes were significant (P<0.05) but the decrease in MAP was again more than VP

Phase Identification and Size Evaluation of Mechanically Alloyed Cu-Mg-Ni Powders

Ternary mixture of Cu, Mg, and Ni with the nominal composition of nanocrystalline Cu50Mg25Ni25 (in at.%) was milled for 25 hours. Analysis of an X‐ray diffraction pattern (XRD) and transmission electron microscopy (TEM) was used to characterize the chemical phases and microstructure of the final product, which is shown to consist of ternary alloy of Cu‐Mg‐Ni with FCC structure along with small amounts of FCC MgO and Mg0.85Cu0.15. The good agreement between the size values obtained by XRD and TEM is attributed to the formation of defect‐free grains with no substructure during ball milling. Dynamic recrystallization may be a possible mechanism for the emergence of such small grains (<20 nm). The particle size distribution and morphological changes of Cu–Mg–Ni powders were also analyzed by scanning electron microscopy (SEM). According to the SEM results, the particle size of the powders decreased with increasing milling time. Lattice parameter of the Cu‐Mg‐Ni ternary FCC alloy formed during mechanical alloying increased with increase in milling time from 3.61 to 3.65 Å after 20 hours milling

Determination of nutrient values of the bivalve Anodonta cygnea in Selkeh area of the Anzali Lagoon during autumn and spring

Anzali Lagoon is one of the most important aquatic ecosystems of Iran which was registered as a Ramsar Convention site in 1999. This valuable ecosystem is located in the south west shores of the Caspian Sea, in Guilan Province. We randomly collected 30 and 20 samples of the bivalve Anodonta cygnea in autumn 2004 and spring 2005 respectively. The Selkeh area was chosen for the sampling because of its availability during autumn. The area receives water from the southern part of the lagoon basin. Nutrient content of the soft tissue of the bivalve was measured. Live sampled bivalves were transferred to laboratory and their length, width, height; total body weight and wet weight of the internal soft part were measured. Moisture, ash, protein, T.V.N, lipid and amino acid contents in soft tissue were also determined. Moisture content in spring and autumn samples were 84.84% and 83.6%, respectively. Ash content in autumn samples was higher than spring samples, being 4% and 2.32%, respectively. Assessment showed protein content in the autumn samples to be 12% while in spring samples this was 10.5%. T.V.N content in autumn and spring samples were 0.031 and 0.003% respectively. Measurements showed that autumn bivalves had 4% lipid content whereas this value in spring samples was 3%. We found Sixtheen amino acids, including seven essential ones in the samples

Tin-doped Indium Oxide (ITO) Nanocrystal Superlattices (Surface Chemistry, Charge Transport, and Sensing Applications)

This cumulative dissertation is based on three publications. It investigates the surface chemistry of nanocrystals (NC), charge transport in NC superlattices, and energy level alignment at organic/inorganic interfaces. The materials of choice are tin-doped indium oxide (ITO) NCs as well as the organic semiconductors metal-4,4',4″,4‴-tetraaminophthalocyanine (M4APc) and perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA). A wet chemical approach is used to synthesize the NCs and to control the doping concentration. Macroscopic superlattices of ITO NCs are prepared by a Langmuir-type self-assembly at the air/liquid interface followed by simultaneous ligand exchange with Cu4APc. X-ray photoelectron spectroscopy (XPS), grazing-incidence small-angle X-ray scattering (GISAXS), and ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy are used to track the chemical changes on the nanocrystals’ surface before and after ligand exchange and develop a detailed picture of the various components which dominate the surface chemistry of this material. It is demonstrated that the semiconductor molecules largely replace the native surfactant from the ITO NC surface and act as cross-linkers between neighboring particles. Transport measurements reveal a significant increase in electrical conductance, suggesting that Cu4APc provides efficient electronic coupling for neighboring ITO NCs. This material provides the opportunity to study charge and spin transport through phthalocyanine monolayers. Next, the choice of the metal center of M4APc is expanded to Cu, Co, Fe, Ni, and Zn. These ligands are incorporated into the array of ITO NCs, and the charge carrier transport and resistance-mediated vapor sensing are investigated. Varying the metal center provides the opportunity to systematically study the sole effect of the tunneling barrier height on charge transport through the nanocrystal array, while all other parameters are kept constant. Transport measurements, focusing on the effect of the metal center of the ligand, reveal a ligand-dependent increase in electrical conductance. The resulting I–V characteristics as well as the temperature dependence of the zero-voltage conductance indicates that at low temperatures, transport across the arrays occurs via a sequence of inelastic cotunneling events. At higher temperatures, a crossover to 3D Mott variable range hopping (VRH) mechanism is observed. The vapor sensitivity of chemiresistors made from ITO NCs arrays is investigated by dosing the sensors with four different analytes and concentrations as low as 100 ppm. By testing different classes of analytes, different selectivities of the materials is also registered, depending on whether the analytes behave more vapor- or more gas-like. Finally, a wide range of substrates (unreactive, reactive or passivated metals and polymers) with different work functions and coupling interactions are used to investigate the electronic structure at the substrate/PTCDA interface by XPS, ultraviolet photoelectron spectroscopy (UPS), and electrostatic calculations. For thick layers of PTCDA, nearly unchanged electron and hole injection barriers on all substrates are observed without any dependence on the type of substrate. For few monolayers of PTCDA, this seemingly universal Fermi level pinning is perturbed depending on the nature of the substrate and the thickness. This behavior is explained with a large induced density of interface states. Using standard electrostatic calculation models as well as introducing extensions to previously reported approaches, the origin of universal Fermi level pinning and its underlying mechanism is investigated. The simulation results demonstrate how the shape of the DOS near the interface has long-range influence on key parameters (e.g. the barrier to charge injection) of the entire organic film.Die vorliegende kumulative Dissertation basiert auf drei Publikationen. Sie behandelt die Oberflächenchemie von Nanokristallen (NC), Ladungstransport in NC Übergittern und die Energieniveauausrichtung an organisch/anorganischen Grenzflächen. Bei den untersuchten Materialien handelt es sich um Indiumzinnoxid (ITO) NCs und organische Halbleiter der Metall-4,4',4″,4‴-tetraaminophthalocyanine (M4APc) und Perylen-3,4,9,10-tetracarbonsäuredianhydrid (PTCDA). Eine nasschemische Herangehensweise wird für die Synthese der NCs und die Kontrolle ihrer Dotierungskonzentration gewählt. Durch eine Langmuir-artige selbst-Assemblierung an der Flüssig-Gas-Grenzfläche mit parallel ablaufendem Ligandenaustausch mit Cu4APc werden makroskopische Übergitter aus ITO-NCs hergestellt. Röntgenphotoelektronenspektroskopie (XPS), Röntgenkleinwinkelstreuung unter streifendem Einfall (GISAXS) und UV/Vis/NIR-Spektroskopie werden verwendet, um die chemischen Veränderungen der Oberfläche der Nanokristalle vor und nach Ligandenaustausch zu verfolgen und um ein detailliertes Bild der unterschiedlichen Komponenten zu erhalten, die die Oberflächenchemie dieses Materials dominieren. Es wird gezeigt, dass die halbleitenden Moleküle die ursprünglichen Liganden von der ITO Oberfläche größtenteils ersetzen und als Vernetzer zwischen benachbarten Partikeln fungieren. Transportmessungen weisen eine signifikante Erhöhung der elektrischen Leitfähigkeit auf und legen damit nahe, dass Cu4APc zu einer effizienten elektronischen Kopplung benachbarter ITO NCs führt. Dieses Material bietet die Möglichkeit, Ladungs- und Spintransport durch Phthalocyaninmonolagen zu untersuchen. Im nächsten Schritt wird die Wahl des Metallzentrums von M4APc auf Cu, Co, Fe, Ni und Zn ausgedehnt. Diese Liganden sind in die Anordnung der ITO NCs integriert, und es werden Ladungsträgertransport sowie die Widerstands-abhängige Detektion von Dampf dieser hybriden Materialien untersucht. Die Variation des Metallzentrums ermöglicht es, systematisch den alleinigen Effekt der Höhe der Tunnelbarriere auf den Ladungstransport durch die Nanokristallanordnung zu untersuchen, während alle anderen Parameter konstant gehalten werden. Transportmessungen, die sich auf den Effekt des Metallzentrums des Liganden fokussieren, zeigen eine Liganden-abhängige Erhöhung der elektrischen Leitfähigkeit. Die resultierende I-V-Kennlinie und die Temperaturabhängigkeit Leitfähigkeit im Niedrigfeld deuten darauf hin, dass bei niedrigen Temperaturen Ladungstransport durch das Gitter durch eine Sequenz von inelastischen Ko-Tunnelereignissen erfolgt. Bei höheren Temperaturen wird ein Übergang zum 3D Mott-VRH Mechanismus beobachtet. Die Empfindlichkeit der Chemosensoren, die aus ITO NCs Anordnungen bestehen, wird gegenüber Dämpfen untersucht, indem die Sensoren mit vier unterschiedlichen Analyten und Konzentrationen – bis hinab zu 100 ppm – beladen werden. Es zeigt sich durch Untersuchung verschiedener Analytenarten, dass das Material unterschiedliche Selektivitäten aufweist, die davon abhängen, ob sich die Analyten eher dampf- oder gasartig verhalten. Zuletzt wird eine Vielzahl an Substraten (inerte, reaktive oder passivierte Metalle und Polymere) mit unterschiedlichen Austrittsarbeiten und Kopplungswechselwirkungen eingesetzt, um die elektronische Struktur der Substrat/PTCDA Grenzfläche mittels XPS, Ultraviolettphotoelektronenspektroskopie (UPS) und elektrostatischen Berechnungen zu untersuchen. Bei dicken PTCDA-Schichten werden, ohne eine Abhängigkeit von der Art des Substrates ausmachen zu können, nahezu unveränderte Elektronen- und Lochinjektionsbarrieren auf allen Substraten beobachtet. Für wenige Monolagen an PTCDA wird diese scheinbare universelle Fixierung des Ferminiveaus abhängig von der Natur des Substrats und der Filmdicke gestört. Dieses Verhalten wird mit einer großen induzierten Grenzflächenzustandsdichte erklärt. Durch Verwendung von standardmäßigen elektrostatischen Kalkulationsmodellen und durch Einführung von Erweiterungen zu bereits berichteten Herangehensweisen wird der Ursprung der universellen Fixierung des Ferminiveaus und dessen zugrundeliegender Mechanismus untersucht. Die Simulationsergebnisse demonstrieren, wie die Form der Zustandsdichte in der Nähe der Oberfläche einen Einfluss langer Reichweite auf Schlüsselparameter (z. Bsp. die Barriere der Ladungsträgerinjektion) des gesamten organischen Films hat

Application of Land Surface Temperature Extracted from Satellite Images for Zoning Reference Evapotranspiration

Reference evapotranspiration is one the most important climatic parameters to determine crop water requirement, climatic and hydrological studies and water resources management. The aim of this study was spatial estimating and zoning of reference evapotranspiration using the MODIS sensor images performed for Sefidroud basin. For this purpose, among the MODIS sensor products, Land Surface Temperature was selected and based on that, daily values of maximum and minimum air temperatures were modeled for studied area using Multiple Linear Regression and non-linear model of Support Vector Machines-based. Then, map of reference evapotranspiration zoning was prepared for studied area using Hargreaves-Samani method. Afterwards, by developing a linear regression model, the extracted reference evapotranspiration from Hargreaves-Samani method was converted to the FAO-Penman-Monteith method and based on that, map of reference evapotranspiration zoning on the basis of the FAO-Penman-Monteith method was extracted for the study area. Based on performed analyses, Support Vector Machine and Multiple Linear Regression models were selected to model minimum and maximum air temperatures, respectively and by applying cross validation method, the adjusted coefficient of determination for these models obtained was 0.81 and 0.92. The results showed that it is possible to make spatial estimation of reference evapotranspiration with an appropriate accuracy by considering an algorithm on the basis of combining satellite-based Land Surface Temperatures and statistical models. Zoning of reference evapotranspiration for any region can be extracted by only having some meteorological data in few point stations and by utilization from the satellite-extracted Land Surface Temperatures

Numerical Simulation of Flow Separation Control using Multiple DBD Plasma Actuators

A numerical simulation method is employed to investigate the effect of the steady multiple plasma body forces on the flow field of stalled NACA 0015 airfoil. The plasma body forces created by multiple Dielectric Barrier Discharge (DBD) actuators are modeled with a phenomenological plasma method coupled with 2-dimensional compressible turbulent flow equations. The body force distribution is assumed to vary linearly in the triangular region around the actuator. The equations are solved using adual-timeimplicit finite volume method on unstructured grids. In this paper, the responses of the separated flow field to the effects of single and multiple DBD actuators over the broad range of angles of attack ( 9^0-〖30〗^0) are studied. The effects of the actuators positions on the flow field are also investigated. It is shown that the DBD have a significant effect on flow separation control in low Reynolds number aerodynamics