ABSTRACT. This study investigates the effect of silica fume (SF) and ground granulated blast furnace slag (GGBFS) on the durability properties of concrete subjected to compressive damage.Portland cement wasreplaced by 10% SF and 60% of GGBFS as a replacement of Portland cement.Thirty-six concrete cylinders (100 x 200 mm) were subjected to three compressive preloading levels (50%, 75%, and 90% of the ultimate strength capacity).After 28 days of curing, the concrete specimens were experimentally tested for electrical resistivity, rapid chloride penetration (RCPT) and the chloride migration.The experimental results showed that the SF increases the compressive strength of concrete by 50% of control concrete.Besides, the GGBFS improves the durability of concrete with the highest electrical resistivity about 4 and 1.85 times the OPC and SF concrete results, respectively. The chloride permeability in GGBFS was found to be about 78% and 65% less than OPC and SF concrete, respectively. The chloride migration coefficient increases in the control samples subjected to 90% compressive damage.However, the replacement of Portland cement with SF and GGBFS improved the concrete durability when subjected to compressive damage up to 90% of the compressive strength

Abstract. As a result of the high improvement rate of carbon nanotubes (CNTs) fabrication process and its tremendous important applications in various fields, the manuscript is devoted to the study of CNTs effective parameters for the case of nano-dimensional networks. It is also called Carbon nanotube networks (CANETs). Parameters such as density, allowable adjacent distance, phase angles and radius of CNTs are determined. Isotropy performance as a function of these CNTs parameters is discussed. This allows us to determine the suitable phase angles and adjacent distance between each one CNT and other in the case of random distribution. Also, the relation between the FET conductance and mobility between the transmitter and receiver destination as a function of different CNTs parameters are theoretically studied. From the resultsobtained, one can recognize that the CNTs properties play an important role for determining the CANETs behaviour. One of the effective CNTs parameters is the longitudinal length, LCNT as it is commonly used in various CANETs figure of merit factors. According to the calculated values of CNTs length and radius, the allowable adjacent distance that achieves high FET conductance is between 3-15nm. The phase angle between CNTs is essential for achieving the intersections, nanonodes, in the path between the destination terminals. As a consequence of random distribution of CNTs in a specified area, the wide range of phase angles is studied from 1.5° to 75° with two degree increments in each step. The important fact that is concluded from the results is that the ability to apply phase angle modulation in the CANETs and its advantages to secure the data until it reaches to the terminal in shortest data path distance. Moreover, the obtained FET mobility values (50-150 cm2/Vs) under considered conditions give the facility to fabricate the CNTs in nanodimensional practical phase processes.

ABSTRACT. The exchange of the medical patient’s information through the Internet, known as Telemedicine, has become imperative. Indeed, for practical purposes, patient files have to be shared to several medical locations (with different specializations, for example) and insurance companies. On the other hand, the privacy and security of a patient’s health information has to be safeguarded. Through the Internet, the patient’s health information can be disclosed or tampered, either accidentally or maliciously. To address this issue, intensive research has been conducted in the last decade to ensure the secure and safe transmission of such information through medical image steganography. This issue is of supreme importance when conducting remote surgeries, also known as Tele-surgery, wherein a doctor is performing surgery on a patient who does not physically share the same location. In this case, real-time security is absolutely needed. As this domain still requires much research, we propose a new steganography technique based on image clustering of the Region of Non-Interest (RONI) of the image. This new technique demonstrates that while the Region of Interest (ROI) in medical image is not used in this process, the robustness against some attacks, such as rotation and cropping, is still highly effective. Results show that this robustness is related to the size of duplication of the embedded stego-information and the dispersal rate of this duplication.

Abstract. This paper introduces a pedagogical method for the derivation of all irredundant dependency sets (IDSs) (and a minimal cover (MC) of the dependency set for relational databases. The paper utilizes an established equivalence between relational database functional dependencies (FDs) and a fragment of switching algebra that is typically built of Horn clauses. Therefore, the paper proposes the employment of various tools of switching theory in the domain of relational databases. In particular, the paper obtains the IDSs and MC of a database dependency set by employing a Variable-Entered Cover Table (VECT) to construct a presence or Petrick Function (PF). The proposed procedure is presented in detail and demonstrated via two illustrative examples. The traditional database approach, adopted by almost all textbooks on relational databases and based on the heuristic application of inference axioms, does not decide whether there is a unique IDS or multiple ones, and does not produce multiple IDSs when these exist. The present procedure, however, produces all (or, at least, as many as required) IDSs, and decides which among them are minimal covers. The present procedure is validated via Karnaugh maps and directed graphs. The paper demonstrates that the current covering problem is of exponential complexity and hence intractable. However, this complexity issue is not of much concern for the current pedagogical application to relational databases.