Sharif Digital Repository

The aim of this paper is to examine the characteristics and conduct of boards in non-financial Malaysian firms, with a particular emphasis on the companies’ financial leverage, using panel data spanning from 2012 to 2018. Overall, the study reveals that the relationship between board attributes and a firm’s financial leverage is significant, but mixed. Notably, we find that extremely small or large boards are ineffective in maintaining the optimal financial leverage level that benefits all stakeholders. Our study concludes that board independence is negatively correlated with financial leverage, whereas the tenure of board members is negatively associated with financial leverage.... 

This study investigates numerically the behavior of tilted angle shear connectors embedded in solid concrete slabs. Two different tilted angle connectors were used, titled angle with 112.5 and 135 degrees between the angle leg and steel beam flange. A nonlinear finite element model was developed to simulate and validate the experimental push-out tests. Parametric studies were performed to investigate the variations in concrete strength and connector's dimensions. The results indicate that the ultimate strength of a tilted angle shear connector is directly related to the square root of the concrete compressive strength. The effects of variations in the geometry of tilted angle connectors on... 

This paper investigates the behaviour of C-shaped and L-shaped angle shear connectors embedded in solid concrete slabs. An effective finite element model is proposed to simulate the push out tests of these shear connectors that encompass nonlinear material behaviour, large displacement and damage plasticity. The finite element models are validated against test results. Parametric studies using this nonlinear model are performed to investigate the variations in concrete strength and connector dimensions. The finite element analyses also confirm the test results that increasing the length of shear connector increases their shear strength proportionately. It is observed that the maximum stress... 

An accurate examination of deformability of rock samples in response to any change in stresses is deeply dependent on the reliable determination of properties of the rock as analysis inputs. Although Young’s modulus (E) can provide valuable characteristics of the rock material deformation, the direct determination of E is considered a time-consuming and complicated analysis. The present study is aimed to introduce a new hybrid intelligent model to predict the E of granitic rock samples. Hence, a series of granitic block samples were collected from the face of a water transfer tunnel excavated in Malaysia and transferred to laboratory to conduct rock index tests for E prediction. Rock index... 

An accurate examination of deformability of rock samples in response to any change in stresses is deeply dependent on the reliable determination of properties of the rock as analysis inputs. Although Young’s modulus (E) can provide valuable characteristics of the rock material deformation, the direct determination of E is considered a time-consuming and complicated analysis. The present study is aimed to introduce a new hybrid intelligent model to predict the E of granitic rock samples. Hence, a series of granitic block samples were collected from the face of a water transfer tunnel excavated in Malaysia and transferred to laboratory to conduct rock index tests for E prediction. Rock index... 

The microfluidic device, known simply as microfluidics, is an emerging technology that has become a significant tool for pharmaceutical businesses to process and analyze materials for developing, optimizing, testing, and delivering various drugs in advanced nanocarriers. Technically, microfluidics is a technique to handle small solution volumes (nanoliters to picoliters) in microchambers of different geometries and dimensions ranging from a few nanometers to hundreds of micrometers. Each year, many pharmaceutical drug delivery systems have failed clinical translation because of scale-up problems. Now, scientists are trying to find some suitable alternatives and more robust methodologies to... 

Abstract: In this investigation, monodisperse CuGaS2 nanoparticles intended for use as visible-light-absorbing materials were synthesized using a facile one-step heating method that involved dissolving the precursors copper chloride, gallium acetylacetonate, and thiourea in a solvent consisting of either oleylamine alone or a combination of oleylamine, oleic acid, and 1-octadecene. The shapes of the resulting nanoparticles were either elongated, polygonal, or a mixture of both, depending on whether the crystal structure of the nanoparticles was predominantly wurtzite, predominantly chalcopyrite, or a more balanced mixture of both wurtzite and chalcopyrite (i.e., the nanoparticles were... 

Wheat stands as the foremost cultivated crop in Pakistan, dominating in terms of acreage and production among cereals. The morphology of wheat grains has been a target of selection since the dawn of agriculture and remains a paramount focus in contemporary breeding efforts. This study sought to examine alterations in grain morphology using digital imaging across 64 bread wheat cultivars grown in Pakistan under both well-watered and water-limited conditions, while also exploring their link with the TaCWI gene. The analysis revealed a substantial range of variation in grain morphology encompassing more than 15fifteen descriptors among the cultivars. Historically significant wheat cultivars,... 

A one-pot method was used to synthesize CuInxGa1-xS2 nanoparticles by substituting In3+ with Ga3+. The samples with composition of gallium ranging from 0% to 100% were synthesized by solving copper chloride, indium trichloride, gallium acetylacetonate, and thiourea as precursors in 1-octadecene, oleylamine, and oleic acid as noncoordinating, coordinating, and capping agent solvents, respectively. Depending on the chemical composition and synthesis conditions, the morphology of the as-synthesized nanoparticles obtained was trigonal, semitrigonal, hexagonal, and quasi-spherical. X-ray photoelectron spectroscopy and X-ray diffraction confirmed that Ga3+ substituted In3+ without any segregation... 

Background: Diesel mainly consists of paraffin and thio-aromatic compounds. Sulfur present in diesel exhaust is the major challenge for oil refineries. Sulfur is an oxidizing element that discharges as acute pollutant in the environment, having adverse effects on human and animal life. Introduction: The scope of this review paper is to discuss and highlight the recent advancements in the process of desulfurization of diesel oil to explore the less energy-intensive and more economical process. Methods: Recently, different techniques are widely used for desulfurization of diesel oil to remove sulfur containing compounds from diesel. These techniques mainly involve hydrodesulfurzation,... 

Background: Water contamination by noxious heavy metals due to urbanization is a global environmental problem. Heavy metal ions pollution makes the water unsuitable for drinking and is also highly toxic to human beings and eco-system. The remediation of heavy metals is therefore very crucial. Methods: Adsorbents based on biopolymer and eco-friendly polymer composites have been developed and fabricated to remediate and remove heavy metals from the ecosystem. Results: In recent years biocomposites have been successful as cost-effective adsorbents for the remediation of various contaminants with their eco-friendly nature and sustainability. Conclusion: This review article gives an overview on... 

Magnetic spinel ferrite nanoparticles (MSF-NPs) are potential candidates for biomedical applications, especially in cancer diagnosis and therapy due to their excellent physiochemical and magnetic properties. In the current study, MSF-NPs were fabricated by sol-gel auto combustion method. The crystal structure and surface morphology were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The magnetic properties were studied by VSM (vibrating sample magnetometer). As increasing Gd3+ concentration, the saturation magnetization values decreased from (17.8-2.3) emu/g, while the coercivity decreased from (499-133) Oe at room temperature. Finally, the fabricated MSF-NPs... 

Using multiple antennas at the transmit and receive sides of a passive radar brings both the benefits of MIMO radar and passive radar. However one of the obstacles arisen in such configuration is the receive antennas placement in proper positions so that the radar performance is improved. Here we just consider the case of positioning one receiver among multiple illuminators of opportunity. Indeed it is a start for the solution of optimizing the geometry of the multiple receivers in a passive radar  

SbCl3 supported on montmorillonite K-10 is an efficient catalyst for the ring opening of epoxides with aromatic amines under solvent-free conditions and microwave irradiation to give the corresponding b-amino alcohols in high yields with high regioselectivity  

In this paper, we consider an integrated sensing and communication (ISAC) system with wireless power transfer (WPT) where an unmanned aerial vehicle (UAV)-based radar serves a group of energy-limited communication users in addition to its sensing functionality. In this architecture, the radar senses the environment in phase 1 (namely sensing phase) and mean-while, the communications users (nodes) harvest and store the energy from the radar transmit signal. The stored energy is then used for information transmission from the nodes to UAV in phase 2, i.e., uplink phase. Performance of the radar system depends on the transmit signal as well as the receive filter; the energy of the transmit... 

One of the important obstacles in MIMO (Multiple Input Multiple Output) radars is the issue of designing proper transmit signals. Indeed, the capability of signal design is a significant advantage in MIMO radars, through which, the system can achieve much better performance. Many different aspects of this performance improvement have been considered yet, and the transmit signals have been designed to attain such goal, e.g., getting higher SNR or better detector's performance at the receiver. However, an important tool for evaluating the radar's performance is its ambiguity function. In this paper, we consider the problem of transmit signal design, in order to optimize the ambiguity function... 

Two gains play key roles in recently developed MIMO wireless communication systems: "spatial diversity" gain and "spatial multiplexing" gain. The diversity gain refers to the capability to decrease the error rate of the MIMO channel, while the multiplexing gain implicitly refers to the amount of increase in the capacity of the MIMO channel. It has been shown that there is a fundamental tradeoff between these two types of gains, meaning interplay between increasing reliability (via an increase in the diversity gain) and increasing data rate (via an increase in the multiplexing gain). On the other hand, recently, MIMO radars have attracted much attention for their superior ability to enhance... 

It is a well known fact that using multiple antennas at transmit and receive sides improves the detection performance. However, in such multiple-input multiple-output (MIMO) configuration, proper positioning of transmitters and receivers is a big challenge that can have significant influence on the performance of the overall system. In addition, determining the power of each transmitter under a total power constraint is a problem that should be solved in order to enhance the performance and coverage of such a system. In this paper, we design the Neyman-Pearson detector under the Rayleigh scatter model and use it to introduce a criterion for the antenna placement at both transmit and receive... 

There has been much interest, recently, towards exploiting the Multiple-Input Multiple-Output (MIMO) technique in radar. It is shown that using multiple antennas at transmit and receive sides can improve the performance of the system. However, in order to analyze the system's performance, its ambiguity function, i.e. the ambiguity function of a MIMO radar, is needed to be defined. In this paper, beginning from the information theoretic definitions, we derive such function, specifically for a MIMO radar with widely separated antennas  

By combining the two ideas of MIMO (Multiple Input Multiple Output) and PCL (Passive Coherent Location) in radar, one can achieve the advantages of both recently developed techniques simultaneously. While using multiple antennas at the receive side provides a spatial diversity of the object to be detected, using multiple illuminators of opportunity, most importantly, makes the radar covert to the interceptors. One obstacle in such MIMO configuration is choosing the positions of the receive antennas. In this paper, after analyzing the Neyman-Pearson detector for the DVB-T based PCL, we introduce the probability of missed detection as a criterion to place the receive antenna. Here, we only...