Sharif Digital Repository

This study investigated the influence of ultrafine fly ash (FA) on the mechanical properties, elevated temperature resistance and water stability of basalt fiber reinforced magnesium phosphate cement, and synergy mechanism was examined with the help of X-ray diffraction (XRD), thermogravimetric analysis (TGA), mercury intrusion porosimeter (MIP) and scanning electron microscopy energy dispersive spectroscopy (SEM/SEM-EDS) analysis techniques. Experimental results showed that incorporation of FA improved the mechanical properties, temperature resistance and water stability of MPC composites. TGA results exhibited that the mass loss of MPC composites was gradually reduced by increasing the... 

Innovation is considered to be a dominant cause for sustainable business success. Knowledge management and intellectual capital are powerful tools to promote innovation in the organization. Therefore, this study aims to explore the influence of knowledge management process and intellectual capital on innovation with the mediating effect of entrepreneurial orientation and moderating role of leader education level. Data were collected from a sample of 393 IT firms listed in the Pakistan Software Houses Association and applied a partial least squares structural educational modeling (SEM) technique. The results show that the knowledge management process and intellectual capital have a positive... 

Connected and Autonomous Vehicles (CAVs) are introduced to improve individuals' quality of life by offering a wide range of services. They collect a huge amount of data and exchange them with each other and the infrastructure. The collected data usually includes sensitive information about the users and the surrounding environment. Therefore, data security and privacy are among the main challenges in this industry. Blockchain, an emerging distributed ledger, has been considered by the research community as a potential solution for enhancing data security, integrity, and transparency in Intelligent Transportation Systems (ITS). However, despite the emphasis of governments on the transparency... 

In this article, a size-dependent generalized thermoelasticity model is established to appraise the small-scale effect on thermoelastic vibrations of Euler-Bernoulli nanobeams. Small-scale effect on the structure and heat conduction is captured by exploiting nonlocal strain gradient theory (NSGT) and nonclassical heat conduction model of Guyer and Krumhansl (GK model). NSGT enables the model to account for both nonlocal and strain gradient effects on structure, and GK formulation empowers the model to incorporate both nonlocal and lagging effect into heat conduction equation. The normalized forms of size-dependent equations of motion and heat conduction are provided by introducing some... 

In this article, a size-dependent generalized thermoelasticity model is established to appraise the small-scale effect on thermoelastic vibrations of Euler-Bernoulli nanobeams. Small-scale effect on the structure and heat conduction is captured by exploiting nonlocal strain gradient theory (NSGT) and nonclassical heat conduction model of Guyer and Krumhansl (GK model). NSGT enables the model to account for both nonlocal and strain gradient effects on structure, and GK formulation empowers the model to incorporate both nonlocal and lagging effect into heat conduction equation. The normalized forms of size-dependent equations of motion and heat conduction are provided by introducing some... 

Structural and dynamic properties of ions confined in nanoslits are crucial to understand the fundamental mechanism underlying a wide range of chemical and biological phenomena. K + and Cl - show similar ion mobilities in a bulk aqueous solution, whereas they exhibit a remarkable difference when transporting through an angstrom-scale channel. Our molecular dynamics simulations uncover that such discrepancy originates from the subtle differences in their hydration structures and preferable locations across the channel. Opposite charge causes different water dipolar orientations around ions, mediating the distance and tribological interactions between hydrated ions and channel's walls.... 

Big Data has various formats, substandard data models, and diverse semantics. Understanding this vast, continuous, and constantly evolving data is challenging and requires sophisticated data science pipelines that not only turn the raw data into contextual knowledge and insights but also generate meaningful and personalized narratives to facilitate the understanding and interpretation of the Big Data. Existing methods often fail to provide the necessary context and personalization to make data actionable to diverse stakeholders. To achieve this goal, we introduce the Open Story Model (OSM), a novel data science pipeline that: i) transforms the unprocessed data into a structured Knowledge... 

Analysis of microparticle size and fluorescence intensity can be used to classify microparticles. We designed and fabricated an optofluidic system that characterizes microparticles, including fluorescent microparticles and microalgae. A new type of multi-pixel photon counter (MPPC) was employed to miniaturize the device, lower its power consumption, and make it insensitive to magnetic fields. The system uses a 635 nm laser for excitation of the microparticles' fluorescence. The scattered light from the fluorescent microparticles, as well as Chlorella vulgaris and Chlorella protothecoides, were measured. Additionally, we analyzed the width and height of the measured signals generated as a... 

A non-terminated, low molecular weight, highly crystalline, linear aliphatic polyester was successfully synthesized via ester-interchange polycondensation of cis-2-butene-1,4-diol and diethyl oxalate by using of lead (II) oxide as the catalyst. No decarboxylation occurred during the optimized polymerization. Structural and Chemical identification was performed by elemental analysis, FTIR, 'H-NMR, and Mass spectroscopy. Some macrocyle species were detected in the product, according to GPC. Fragmentation patterns were suggested for the main m/e's of the mass spectrum. Thermal characterization was performed by DSC and TGA. It was found that the overall thermal stability of the polyester is... 

Lake Urmia in Iran has undergone catastrophic desiccation due to increasing anthropogenic development, especially in the agricultural sector. A paramount national goal is to restore the lake to its former healthy condition, but corresponding water governance and restoration efforts have encountered various, mostly human-related, challenges. We argue here that these challenges stem from lack of awareness and insufficient consideration of the local social conditions and the subtleties of human-water interactions, which we collectively refer to as socio-hydrological barriers. Ignorance of such socio-hydrological barriers can lead to policy efforts that are mismatched with local realities and,... 

Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model... 

In the present study, the development of a neutron noise simulator, DYN-ACNEM, using the Average Current Nodal Expansion Method (ACNEM) in 2-G, 2-D hexagonal geometries is reported. In first stage, the static neutron calculation is performed. The neutron/adjoint flux distribution and corresponding eigen-values are calculated using the algorithm developed based on power iteration method by considering the coarse meshes. The results of the static calculation are validated against the well-known IAEA-2D benchmark problem. In the second stage, the dynamic calculation is performed in the frequency domain in which the dimension of the variable space of the noise equations is lower than the time... 

In this paper, we describe the design, development and preliminary evaluation of a novel animation tool for smartphones and tablets, with the goal of improving creativity and problem-solving ability among novice users, mainly young children. The user first draws the objects with markers and crayons on paper and takes a photo with their mobile or tablet to import their drawings into the app as game sprites. They then design their animation scene and point to a part of the character and selecting its animation type from existing buttons. Hence the selected part is animated in a vertex shader while ensuring a smooth transition with the non-pointed part. The results of a preliminary evaluation... 

In this study, the SD-HACNEM (Sharif Dynamic - High order Average Current Nodal Expansion Method) neutron noise simulator in two energy groups using a second-order flux expansion method for two-dimensional rectangular X Y-geometry has been developed. In the first step, the calculations were performed for the steady state and results of ACNEM (Average Current Nodal Expansion Method) and HACNEM (High order Average Current Nodal Expansion Method) were examined and compared. To solve the problem, the power iteration algorithm has been used to calculate the distribution of neutron flux and neutron multiplication factor by considering the coarse-mesh (each fuel assembly one node). To validate the... 

Carbon-based perovskite solar cells (C-PSCs) have been considered to be promising candidates towards commercialization, due to their relatively low-production cost and excellent stability. However, the defects of the perovskite film and the mismatched energy level arrangement between perovskite layer and the carbon electrode (CE) severely limit the power conversion efficiency (PCE) of C-PSCs. Here, we incorporated pure-phase two-dimensional (2D) perovskite crystal (OA)2PbI4 (OA=n-octylammonium) as a passivation layer atop of 3D perovskite layer in C-PSCs. The modified films show significantly reduced defect state density, optimized energy level arrangement, and enhanced hydrophobicity. As a... 

We consider the stochastic queue core problem on a tree network. Our aim is to find an optimal path on a tree network subject to the average travel time of particles moving along the tree for service given by a server traversing along the optimal path. We assume that particles originating at a node on a tree network request their demands for service randomly and the server is modeled first by an M/M/1 and then by an M/G/1 queue using the FIFO discipline. We consider that all paths along which the particles travel are modeled with an M/G/c/c state-dependent queue with the particles being independent of each other having demands according to the Poisson distribution. Two algorithms are... 

We consider the stochastic queue core problem on a tree network. Our aim is to find an optimal path on a tree network subject to the average travel time of particles moving along the tree for service given by a server traversing along the optimal path. We assume that particles originating at a node on a tree network request their demands for service randomly and the server is modeled first by an M/M/1 and then by an M/G/1 queue using the FIFO discipline. We consider that all paths along which the particles travel are modeled with an M/G/c/c state-dependent queue with the particles being independent of each other having demands according to the Poisson distribution. Two algorithms are... 

Macrobenthos animals are an architect of a variety of roles including as a part of the food web of aquatic ecosystem and improve the structure of the sediment and can determine the quality of the water. Macrobenthos communities have shown their potential role in biomonitoring to analyze contaminant loads due to high sensitivity to organic pollutants along the coastal water area. Besides, it is also used to determine heavy metals and petroleum hydrocarbons in coastal water due to their long sustainability with chemicals are primarily related with industrial calamities and occupational activities. Based on above perspectives, this systematic review has shown interesting findings about the... 

Controlling networked structures has many applications in science and engineering. In this paper, we consider the problem of pinning control (pinning the dynamics into the reference state), and optimally placing the driver nodes, i.e., the nodes to which the control signal is fed. Considering the local controllability concept, a metric based on the eigenvalues of the Laplacian matrix is taken into account as a measure of controllability. We show that the proposed optimal placement strategy considerably outperforms heuristic methods including choosing hub nodes with high degree or betweenness centrality as drivers. We also study properties of optimal drivers in terms of various centrality...