Sharif Digital Repository

Energy use in buildings contributes a large part in global energy demand. To reduce energy use in this group of consumers, specially in cold seasons, an automatic control technique is proposed. In this paper, a model predictive controller (MPC) is employed to minimize the boiler activation time. The method uses the building model and incorporates the weather forecast data to act on the actuator in an optimal fashion while treating the user comfort constraints. This technique, as a part, can be embedded into the building energy management system. The building model parameters are obtained via an online identification process using unscented kalman filter (UKF). This identification is... 

This paper proposes a multi-unit building model, in which the parameters are obtained via an online identification process. The identification process is carried out on-the-fly so it can update the best model of the building units. A model predictive controller (MPC) is also employed that uses the prediction of the building model, as well as the weather forecast data and acts on the heating boiler in an optimal fashion. In addition, since the controller is designed for a multi-unit building, it is crucial to estimate the amount of the delay that takes the hot flow to reach the units. This paper presents a very simple method for the delay identification based on unscented kalman filter. For... 

In order to design Button Beam Position Monitors (BPMs) for synchrotron facilities, one algorithm by C# have been developed which can calculate all required parameters to analyze optimal design based on vacuum chamber and button dimensions. Beam position monitors are required to get beam stabilities on submicron levels. For this purpose, different parameters such as capacitance, sensitivity versus bandwidth, intrinsic resolution, induced charge and voltage on buttons are calculated. Less intrinsic resolution and high sensitivity and capacitance are desired. To calculate induced charge and voltage on each button, Poisson's equation has been solved by Green method. For sensitivities... 

A large portion of the railway bridge stock in many countries is comprised of masonry arch bridges. During recent years, more attention has been paid to the maintenance of such structures. Rehabilitation and retrofitting methods have been proposed to enhance the performance of masonry arch bridges and extend their service life. Because a large portion of forces exerted on such structures comes from the railway track and passing trains, structural elements are added to the track to reduce the forces transmitted to bridges. One such element is the ballast mat, which, according to suppliers, has a positive impact on the structural performance of the track. This paper tries to assess the effects... 

In this paper, we present an MPEG-2 video decoder implemented in our ODYSSEY design methodology. We start with an ASIP tailored to the JPEG decompression algorithm. We extend that ASIP by required software routines such that the extended ASIP can now perform MPEG2 decoding while still benefiting from hardware units common between JPEG and MPEG2. This demonstrates the ability of our approach in extending an already manufactured ASIP, which was tailored to a given application, such that it implements new, yet related applications. The implementation platform is a VirtexII-Pro FPGA. The hardware part is implemented in VHDL, and the software runs on a PowerPC processor. Experimental results show... 

In this paper, we present a JPEG decoder implemented in our ODYSSEY design methodology. We start with an object-oriented JPEG decoder model. The total operation from modeling to implementation is done automatically by our EDA tool-set in about 10 hours. The resultant system is a JPEG decoder ASIP whose hardware part is implemented on FPGA logic blocks and software part runs on a MicroBlaze processor. This ASIP can be extended by software routines to implement the motion JPEG or MPEG2 decoding algorithms. We implemented our system on ML402 FPGA-based prototype board. Experimental results show that our ASIP implementation is comparable to other approaches while our approach enables quick and... 

The growing complexity of today's embedded systems demands new methodologies and tools to manage the problems of analysis, design, implementation, and validation of complex-embedded systems. Focusing on this issue, this paper describes a design and implementation toolset using our ODYSSEY methodology, which advocates object-oriented (OO) modeling of embedded systems and its ASIP-based implementation. The proposed approach promotes a smooth transition from high-level object-oriented specification to the final embedded system, which is composed of hardware and software components. The transition from higher to lower abstraction levels is facilitated by the use of our GUI, which supports the... 

Prediction of supersolubility and the width of the metastable zone has been a major concern among the workers in the field of industrial crystallization. Operation of crystallizers under the optimum supersaturation low enough to attain the desired product quality (Median Particle Size, Crystal Size Distribution (CSD), Shape, Purity) being one motif. The inherent relationship between the subject and the most fundamental concepts of crystallization being the other. Studying the conditions of primary homogenous nucleation and the crystal growth kinetics has been conducted for a wide range of inorganic materials. A simple probabilistic term called chance of having the desirable species... 

Drop formation in cross-junction micro-channels is numerically studied using the lattice Boltzmann method with pseudo-potential model. To verify the simulation, the results are compared to previous numerical and experimental data. Furthermore, the effects of capillary number, flow rate ratio, contact angle, and viscosity ratio on the flow patterns, drop length, and interval between drops are investigated and highlighted. The results show that the drop forming process has different regimes, namely, jetting, drop, and squeezing regimes. Also, it is shown that increasing in the flow rate ratio in the squeezing regime causes increment in drop length and decrement in drops interval distance. On... 

In the present study, the effect of the number of stages of Tesla Micro-Valve (TMV), as well as the dependency of Reynolds number, Re, on the valve performance has been analyzed. For this purpose, different layouts include one to four-stage with different sizes are investigated numerically. The main criterion for evaluation of valves performance is diodicity, Di. Unsteady and steady flow in valve have been simulated and compared. It is shown that although there are some difference but the trend is similar for both responses. Finally, 2-D and steady state computations of the fluid flow have been utilized that reveal a strong dependence of Di on Re and pressure drop, ΔP. The results showed... 

In this study, the performance of Tesla-type microvalves, used in micropumps for low frequency driving force, is examined. Three-dimensional and unsteady numerical analysis of fluid flow inside a valveless reciprocating micropump in the range of low working frequencies is carried out. Reciprocating movement of flow actuator provides the actuation and pumping of the working fluid. Ferrofluidic valveless micropump is one practical sample of this kind of micropumps that operate in the range of low working frequencies. To model the reciprocating movement of flow actuator, two time varying functions that includes sinusoidal and step excitation are employed. Also, the performance of... 

A family of Zn(II) complexes with naphthadiaza-crown macrocyclic host molecules (Ln = L1-L4) were prepared and characterized employing mass spectrometry, elemental microanalysis, 1H, 13C NMR, IR, UV–vis, fluorescence spectroscopy. The fluorescence study on [M(II)Ln]2+(M = Zn with n = 1–4, Hg with n = 5) complexes denoted on the presence of a notable selective supramolecular interaction with C60 in two different solvents, namely N-Methyl-2-pyrrolidone (NMP) and chloroform for both [Zn(II)L4]2+ and [Hg(II)L5]2+. Employing both UV–vis and fluorescence spectroscopy, 1:1 mol ratio were determined for [M(II)Ln]2+/C60 by applying the Job's plots. Comparing with their free ligands Ln interactions,... 

An efficient and one-pot procedure is described for the synthesis of a variety of derivatives of 1,2-dihydrobenzo[f]chromen-3-ones and 3,4-dihydrochromen-2-ones under solvent-free conditions via a pseudo-four-component domino reaction of acetic anhydride, aryl aldehydes, glycine-based dithiocarbamates, and phenols/naphthols in the presence of l-proline and H4[Si(W3O10)4].xH2O as green catalysts. All products were made under the green strategy for the synthesis of corresponding products with excellent yields (up to 94%) and diastereoselectivity. © 2021 Taylor & Francis Group, LLC  

This study reports on the simulation of temperature distribution of human tooth under a laser beam based on non-Fourier models. The temperature in the tooth depth that directly results from the conduction heat transfer process is caused by the lengthy thermal relaxation time in the tooth layers. A detailed tooth composed of enamel, dentin, and pulp with unstructured shape, uneven boundaries, and realistic thicknesses was considered. A finite difference scheme was separately adopted to solve time-dependent equations in solid layers and soft tissue of the tooth. In this study, a dual-phase-lag non-Fourier heat conduction model was applied to evaluate temperature distribution induced by laser... 

In this study, a dental short pulse laser with a Gaussian beam profile was applied normally to the top surface of a mineral organ i.e. the human tooth for a root canal therapy. A numerical method of finite difference is adopted to solve the time-dependent heat transfer equation. The real boundary conditions of thermal insulation on the sharp segment of the root canal and periodic heat flux on the top boundary of the tooth were applied. The comparison of a three-phase-lag (TPL) bio-heat transfer model with other heat transfer studies has shown that this new bio-heat model (TPL) could accurately predict the thermal behaviour of a non-homogeneous structure such as the human tooth. It was... 

Load Balancing has many applications in various systems, but specifically plays a major role in the efficiency of parallel and distributed systems. In these systems, by load balancing we mean scheduling the jobs in a way that every job could be executed concurrently while it is mapped to a processing unit, such as a processor (in a multi-processor system) or a computer (in a grid computer). By developing effective methods the whole program time execution will be decreased and process utilization will be optimized. In this paper, a solution is proposed for dynamic load balancing. Because of the NP-hard nature of the problem, heuristic methods are desired. A simple scheduling method, Round... 

A novel and efficient multicomponent reaction for the synthesis of polysubstituted pyrrolidine derivatives is described under catalyst-free conditions using ultrasonic irradiation. The reactions were performed via a one-pot four-component condensation of secondary amines, carbon disulfide, isocyanides, and gem-dicyano olefins at room temperature to afford polysubstituted pyrrolidines diastereoselectively in 56-96% yields. This is the first report of a Mumm-type rearrangement with dithiocarbamates followed by intramolecular cyclization, which leads to the preparation of the key structure of pyrrolidine. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche...