Sharif Digital Repository

Al–5·6Zn, Al–5·6Zn–2·5Mg and Al–5·6Zn–2·5Mg–1·6Cu (wt-%) powder blends were compacted at 350 MPa and sintered in nitrogen at different temperatures to study microstructural evolution during sintering. Densification, dimensional changes and mechanical properties of the Al alloys were investigated. Microstructural analyses were performed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and simultaneous thermal analysis (STA) in order to determine the temperature and chemical composition of the phases formed during sintering. It was shown that various liquids and intermetallic phases including Al0·71Zn0·29 at 438°C,... 

Although flooding and its variants are widely deployed for broadcasting by different applications, there are limited results on a complete and comprehensive analytical framework describing their behavior in general cases. We have previously published results which provide an upper bound for the performance of flooding when flooded packets have the highest serving priority. In this paper, using a different and simpler approach, we develop an analytical framework for analysis of flooding in general cases where flooding packets do not receive any special priority treatment in the network. The analysis is performed for a static multi-hop ad hoc wireless network using CSMA as its MAC layer. The... 

There are applications where important and critical data should be sent to all nodes in a wireless Ad-hoc network. Flooding and its variants are typically used to achieve this target. Network coding can also be used for broadcasting in such an environment. Energy consumption in the network, coverage and total delay are all important parameters that should be considered when an algorithm is evaluated. In this article, a reliable and energy efficient single source broadcasting algorithm is proposed based on network coding. This algorithm guarantees the delivery of desired messages to all network nodes, consumes less energy compared and reduces the total delay compared to other algorithms. This... 

The purpose of this research study is to evaluate the solutions of Titanium and Aluminum alloy nanofluidic model with gyrotactic microorganisms (TAA-NFMGM) by applying stupendous knacks of Bayesian distributed adaptive neural structure (BDANS). The use of nanofluids containing gyrotactic microorganisms in combination with titanium and aluminum alloys have potential applications in diverse fields, including engineering, bioremediation, biomedical devices, biotechnology, and research depending on different factors like design of the system and use of certain microorganism. A dataset for BDANS is generated for the eight different events with Adam numerical technique for TAA-NFMGM by varying... 

This research work presents the numerical solution of the Darcy-Forchheimer flow of Casson nanofluidic model (DFFCNFM) on stretching sheets with Newtonian heating by utilizing a combination of nonlinear input-output neural networks with backpropagation of Levenberg-Marquardt computational approach. The presented study investigates the impact of electroosmosis forces on the boundary layer of the Casson nanofluid, focusing on viscous and Joule dissipations. A dataset for DFFCNFM is generated for the different events with backward differentiation formula (BDF) by varying Casson fluid parameter (β), permeability parameter (Da), electric parameter (E1), Reynolds number (Re) relative to stretching... 

The presented work examines the dynamics of convective Eyring–Powell magneto-nanofluid model (CEP-MNFM) with a stretching cylinder by using stupendous knacks of supervised stochastic Levenberg–Marquardt intelligent networks (SSLMINs). The partial differential equations governing the CEP-MNFM are reduced into coupled ODEs by incorporating the similarity transformations. The dataset of the proposed SSLMINs approach is generated with state-of-the-art Adam numerical method for seven different scenarios of CEP-MNFM including variation of radiation, Brownian diffusivity, and thermophoresis parameter, as well as, Biot, Schmidh, and Prandtl numbers. The reference dataset is further utilized for... 

Flooding and its variants are the simplest and most widely used broadcasting methods. Therefore, analysis of its performance in an ad-hoc environment using realistic assumptions is an important research topic. In this article, deploying a rigorous theoretic analysis, an upper bound on the performance of probabilistic flooding running over CSMA as a real and suitable MAC layer protocol for broadcasting scenarios is derived in a static multi-hop ad-hoc network in saturated condition. This model reveals the relation between network parameters and the performance of flooding and thus, helps the designer to have a better understanding of the effect of different design parameters. Using this... 

Flooding technique is widely using to manipulate sensor network essential activities such as synchronization, data gathering, network query and in-network information processing. Reliable and low latency data broadcasting is the primary goal in design of appropriate quality of service aware flooding algorithm. This paper proposes a new error-rate adaptive reliable data flooding strategy. Energy consumption which it the main limitation in sensor network, has been considered in optimal presented scheme. Also the tradeoff between reliability, power consumption and latency has been cared to achieve the finest devise. The simulation results have shown significant enhancement in quality of data... 

We prove the existence of relatively large Goos–Hänchen (GH) shifts for graphene in the presence of an applied strain in different crystallographic directions for p and s polarized beams. It is shown that GH shifts are smoothly increased by stretching the graphene’s lattice. Moreover, we investigate the GH effect for strained graphene as a function of Fermi energy, which can be controlled by external factors such as gate voltage. We show that applied strain along zigzag and armchair orientations gives different results for GH shifts, which could provide a proper tool for the detection of strain in graphene. © 2022 Optica Publishing Group  

The original article contained a mistake in Equation 1. The corrected Equation 1 is shown below: MX+Cx+Kx=f.The original article has been updated © Springer Nature B.V. 2022  

In this study, a general 3D distributed modeling of Trolling-Mode AFM (TR-AFM) as a nanorobot is presented to analyze the 2D manipulation process of a spherical cell. To this aim, the analysis is categorized into 3 sections. In the first section, 6 deformations of TR-AFM are taken into account, and the standard model of the system is obtained. Moreover, the system is simulated in ANSYS Workbench. The results of modal and transient analyses of the system from both analytical and software methods reveal high agreement, which confirms the accuracy of the presented analytical model. In the second section, by utilizing the 3D derived model, displacement of a spherical yeast single cell (W303)... 

The anatase phase of titania was stabilised with physically modifying particulate sol-gel process. Two major parameters, peptisation temperature and drying temperature, were identified which were responsible for retarding the anatase to rutile phase transformation, crystal growth and packing of primary particles. The critical nucleus size of transformation was controlled by natural (at 25 °C) and artificial (at 50 and 70 °C) peptisation techniques. Moreover, sintering of primary particles was controlled by cool (at 0 and 5 °C) and normal (at 25 °C) drying techniques. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed that a full conversion of titanium isopropoxide is obtained... 

Flow through the pores of granular materials has many instances in practice. Therefore, it is interesting to realize how some parameters, such as the shape of the particles affect the passing flow. Following the recent mathematical theory proposed by the authors, this paper deals with the issue of how tortuosity and permeability are influenced by the particle shape. Comparison of the results with the experimental data reveals the competency of the theory in predicting the impact of particle geometry  

Although different broadcasting techniques are widely deployed in wireless networks, there are limited comprehensive analytical frameworks to evaluate the performance of such schemes. In this paper, based on a rigorous theoretical analysis, upper bounds on the network coverage and the total number of transmissions (corresponding to network energy consumption) of flooding and its popular variant probabilistic flooding are derived. The analysis is performed for a static multihop ad hoc wireless network when the network is in saturated condition. To consider a realistic medium-access control (MAC) layer algorithm, successful signal reception is based on the protocol model, and nodes employ... 

This study concentrated on the formulation of self-flowing and an energy efficient lightweight aggregate foamed concrete (LAFC) to be employed as thermal insulation, thermal mass and structural material. Low density concrete mixtures (for the density values from 800 to 1300 kg/m3) were prepared by changing the volume of lightweight expanded clay aggregate (ECA) from 49.4% to 20.1%. Flowing properties of concrete mixtures were improved with the help of stable foam. Ordinary Portland cement (OPC) was replaced by the 5% and 10% silica fume (SF) to examine the influence of SF on the properties of LAFC. Compressive strength and tensile strength of LAFC mixtures were respectively enhanced from 6.5... 

Mobile devices are equipped with a multi-core heterogeneous processing architecture to balance the trade-off between performance and power efficiency. To take advantage of this architecture, in this paper, we propose a task scheduling algorithm that allocates the cores to computation tasks and adjusts the cores' operating frequency by using the dynamic voltage and frequency scaling (DVFS) technique. Our objective is to minimize the battery energy consumption of devices. We also consider offloading the tasks to a cloud server to address their ever increasingly computation demand. In order to design the task scheduling algorithm, we first formulate a combinatorial optimization problem. To... 

This study empirically investigates how companies listed on the Pakistan Stock Exchange (PSX) manage their earnings from 2010 to 2019. It also examines the impact of Corporate Governance (CG) on the choice of Earnings Management (EM) strategies among these companies. The study employs data from companies listed on the PSX during the period from 2010 to 2019 to test these relationships. Researchers in current research used discretionary accrual as proxy to measure the EM by using the model that was modified by Jones. Future probability is measured a year ahead cash flow taken from operation, that is, a year ahead discretionary income and a year ahead earnings’ change. To conduct empirical... 

For the present article, a pulsating heat pipe (PHP) is fabricated and tested experimentally by bending a copper tube. The effects of working fluid, heat input, charging ratio, inclination angle, magnets location, and ferrofluid (magnetic nanofluid) volumetric concentration have been investigated on the thermal performance of this PHP. Experimental results show that using ferrofluid as a working fluid improves the thermal performance of the PHP significantly. Moreover, applying a magnetic field on a ferrofluidic PHP reduces its thermal resistance. By changing the inclination angle of the PHP from vertical mode to angles close to the horizontal mode, the present PHP has a constant and...