The paper presents new studies on numerical modeling (FEM) for beam-to-column behavior under sagging and hogging bending moment when the framework is exposed to service and unexpected loads that may cause a column loss scenario. This investigation is focused on four bolts end-plate joints with 10 mm thickness which are proven experimentally to have more ductile behavior than other end-plates joints (6, 8 bolts), spite of their weakness to transfer the unexpected loads from the initial state to a residual state of the stable equilibrium, that leads to a failure of limited floor area to adjacent joints when tested experimentally (Saleh, 2014). FEM technique used in this research is an extension of the previous technique and is characterized by the use of a more sophisticated technique than the previous, discovered from the result of continuous research and the use of all the options available in the new version of commercial ABAQUS/CAD software. The elements are designed using multiple layers of specific elements of a brick arranged in such a way that the mesh nodes of the tiles should coincide with certain layers with the top of the shear inlay and in line with reinforcement, not as the former study that used thick shell elements to model the reinforced concrete slab with total negligence of reinforcing steel and bolts between the slap and the beam. This investigation is very complex because of highly nonlinear effects associated with the prediction of joint performance, such as structural imperfections, huge displacements and large rotations, inelastic properties of steel and concrete, bonding effects between steel and concrete, friction between …

The aim of the present paper is focused on nucleation onset and development morphologies of acicular ferrite and to evaluate microstructure and mechanical properties during isothermal austenite transformation in titanium free micro-alloyed steel. Isothermal treatment was carried out in the temperature range 350 to 450 C. These treatments were interrupted at different times between 2 and 1800 s in order to analyze the evolution of the microstructure. Yield stress was determined by compression testing on samples with final Microstructure. The metallographic evaluation was done by using optical and scanning electron microscopy (SEM) enabled determination of the nucleation onset at all treatments and subsequent on the development of acicular ferrite of isothermally treated titanium free micro-alloyed steel. The results show that during continuous cooling, dominantly acicular ferrite microstructure is formed. Main characteristics of acicular ferrite are intragranular nucleation and strongly disorganized microstructure with a larger ability to deflect cracks. Acicular ferrite is, therefore, widely recognized to be a desirable microstructure due to good mechanical properties.

Available transfer capability is an index to measure the security and economic viability of an interconnected system. However, to accurately determine this index, other associated parameters need to be accurately evaluated. One of these parameters is the capacity benefit margin (CBM). For efficient power generation reliability and sustainability, a certain amount of supply capacity is commonly reserved by utilities, which in most cases remain unused, to reduce the effect of generation outage. To minimize this unused reserve, utilities usually reserve a predetermined amount of tie-line capacity between interconnected areas to have access to external supply. This tie-line reserved for this purpose is termed as capacity benefit margin (CBM). In this paper a technique for computing CBM is used, the sensitivity of CBM support from other areas to the increase in load in one of the areas is investigated, and conclusively, demand side management is proposed to improve the quantification of CBM. The contribution of this work is the assessment of the CBMs support from other areas during a critical condition, using the flexibility of DSM technique. The modified 24-bus IEEE reliability test system is employed for the verification of the approach.

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ABSTRACT

Swirl stabilised combustion is one of the most widely used techniques for flame stabilisation in gas turbine combustors. Lean premixed combustion systems allow the reduction of NOx coupled with fair flame stability. The swirl mechanism produces an aerodynamic region known as central recirculation zone (CRZ) providing a low velocity region where the flame speed matches the flow velocity, thus anchoring the flame whilst serving to recycle heat and active chemical species to the root of the f

ormer. Another beneficial feature of the CRZ is the enhancement of the mixing in and around this region. However, the mixing and stabilisation processes inside of this zone have shown to be extremely complex. The level of swirl, burner outlet configuration and combustor expansion are very important variables that define the features of the CRZ.

Therefore, in this paper swirling flame dynamics are investigated using computational fluid dynamics (CFD) with commercial software (ANSYS). A new generic swirl burner operated under lean-premixed conditions was modelled. A variety of nozzles were analysed using several gaseous blends at a constant power output. The investigation was based on recognising the size and strength of the central recirculation zones. The dimensions and turbulence of the Central Recirculation Zone were measured and correlated to previous experiments. The results show how the strength and size of the recirculation zone are highly influenced by the blend and infer that it is governed by both the shear layer surrounding the Central Recirculation Zones (CRZ) and the gas composition

. The aim of the present paper is focused on post weld heat treatment qualification by

describes the results of an investigation to understand the micro structural changes that taken place in type 304L stainless steel weld deposits as function of temperature / time by showing any presence of re-crystallization and / or strain induced grain boundary migration and the dissolution of any carbide formed at grain boundaries in welding monitored by metallographic examination.

The ceaseless efforts by power system industries to promote sustainable and competitive electric power market structure in the deregulated environment have given rise to enormous research in the area of transfer capability of transmission networks. Due to high demand for electricity, transmission components are stressed to operate close to their operating limits, and this leads to a decrease in transmission efficiency. To address this issue, efficient evaluation of available transfer capability (ATC) is crucial for system planning, operation, and control. Several approaches have been proposed for ATC computation. Surprisingly, a comprehensive literature review on ATC computation is yet to be efficiently presented. Researchers have been able to come up with fast algorithms, but most of these algorithms are not accurate, and the presented accurate techniques are not fast enough for online applications. This paper presents a comprehensive review of the different approaches for ATC determination. It provides the concepts, methods, and the features of the ATC. For each technique, the state of the art of the several contributions made by researchers has been highlighted. This review reveals that there are issues regarding ATC calculation methods that need attention: the development of fast and accurate algorithm incorporating system dynamics and system uncertainties in ATC determination. Additionally, efforts on the incorporation of renewable energy generation in the ATC evaluation need to be intensified. This review will serve as one in all for researchers as well as a guide for the entrants in this field.

The main objective of this paper is to study the effect of replacing

the internal casing of water boiler that made of metallic material by a

similar one made of composite materials. An intensive theoretical study

have been carried out on domestic electrical water boiler using modeling

technique. Analysis and modeling process was performed using Finite

Element Method. Thermal conductivity which is the main parameter

affecting heat transfer has been tested for composite material as well as

for metallic materials. Results showed that it is more convenient to use

composite material for inner case of water boiler instead of metallic

material. Composite materials are lighter than metallic material, much

safer (eliminate possibility of electrical shock), and it hasn't corrosion

problems. It is found that it is possible to replace the internal case of

water boiler made of metallic material with a wall thickness of 7 mm by

an equivalent composite material case made of glass fiber with the same

thickness. Obtained results showed that seven layers of composite

materials forming similar wall thickness is an optimum case with respect

of heat transfer and thermal conductivity.

Abstract Rapid Prototyping of embedded hardware/software systems is important, because it shortens the path from specification to the final product. Prototypes play a major role in decision making, concept and design validation, feature and limit exploration, as well as design verification in every phase of the product development cycle, including product planning, requirement engineering, and product development. Rapid prototyping of embedded systems can emulate different kind of processes, through the mathematical modelling that represent their dynamic characteristics. This make easier to emulate different control strategies, which can interact with the real signals of the embedded process, making a better approach of the real response than a simple simulation. This paper presents the results of the emulation of the dynamic behaviour in the study case to work, in order to validate control strategies like PID and Fuzzy, using the concepts of rapid prototyping and hardware-in-the-loop (HIL). To achieve this objective, two embedded systems were employed, the first one to emulate the dynamics of the process, and the second one to implement the control strategy. Both systems were interconnected using the Controller Area Network protocol (CAN). The principal contribution of this work is the methodological development in the application of the control strategies through HIL 

Abstract The characteristics of non-minimum phase and static unstable of a tail controlled tactical missile are presented firstly. Then, in order to eliminate the static error, a cascade PI compensator was introduced to the classic two loop autopilot. Due to the slow tracking for command acceleration, the longitudinal three-loop autopilot design is driven based on LTI model of missile plant to stabilize the non-minimum phase static unstably missile airframe. The focus is to explain the performance and the control effect at different values of velocity and stability derivative (𝑀𝜶) of two algorithms on missile plant. The analysis is executed by establishing a standard algorithm in virtue of MATLAB/Simulink for autopilot design. The simulation results indicated that three-loop topology gives better tracking than two-loop with a cascade PI compensator at different value of stability derivative 𝑀𝜶. On the other hand, two-loop has a better response and less control effort at different velocities. fin angle and fin angle rate are less than the three loop for static unstable and stable missile.