Simulation of Laser Thermal Interaction with Titanium Dioxide /Polyvinyl Alcohol Nanocomposite Thin Films
International Journal of Science and Engineering Applications
The aim of this work is to use the computational simulation to define the operational conditions to achieve the desired process. The diagnostic tests were used to guide the experiment where PVA composites doped with Titanium dioxide nanoparticles were irradiated with nitrogen laser in order to modify its properties. The temperature of the samples with different laser fluencies were simulated using finite element method, in COMSOL program, to predict the fluencies that is suitable to use for
... fication before reaching the decomposition temperature of the nanocomposite sample to make sure not to cause any damage. The optical and thermal properties were experimentally studied, and the results were used to define the absorption coefficient and the thermal conductivity of the studied nanocomposites Abstract: In this paper we proposed advanced technologies to provide tremendous support for network administrators by implementing a secure remote system administration app that runs on android smartphones to aid them administer their servers remotely when they (network administrators) are out stationed using their smartphones. The android app developed in eclipse establishes a secure connection with a remote server running a PHP application. The app was developed based on the Remote Frame Buffer (RFB) protocol. The RFB protocol, a display protocol has some security lapses including being vulnerable to Man-In-The-Middle (MITM) attack using a few tools and techniques. This research therefore incorporated a self-signed Secure Socket Layer (SSL) certificate in the android app to enable secure encrypted connections to be established between the android app and the remote server to ensure end-to-end security against attacks such as Man-In-The-Middle (MITM). The whole system was deployed based on client-server architecture with the hand-held smart devices as clients, providing real-time network access to network administrators to their remote servers. The secure RFB protocol proposed and implemented in the android app was compared with other existing software for remote system administration such as Remote Desktop (RDP), and RFB protocols using ICMP ping command. The results show that the average response time of the RDP protocol was 436ms, that of the RFB protocol was 496ms and that of the android app which is based on a proposed secure RFB protocol was 474ms. To evaluate the security of current remote access technologies To implement a smartphone app for remote system administration based on a proposed secure RFB protocol To evaluate the performance of existing remote access technologies as against a proposed secure RFB protocol. SYSTEM OVERVIEW The purpose of the system is to allow system administrators monitor and administer their computer networks remotely using their android smartphones. With this system, a system administrator can create a user remotely, create, view and modify text files remotely, check network status, shutdown a server and set user privileges. The system was developed based on a proposed secure RFB protocol with self-signed Secure Socket Layer (SSL) certificate incorporated into this RFB protocol to ensure endto-end encrypted connections between the smart device (client) and server. The system can be used to monitor and administer only one server at a time. Remote Server PHP processes Commands Send Command Send Response Keeps track of users and activity performed Figure 3: Flow of system. Source: Authors' construct 2015. Evaluation of existing Remote Access Technologies The All remote access systems or applications are developed based on existing and or appropriate technology or technologies. Some existing technologies available for developing remote access systems are: i. The Remote Frame Buffer (RFB) protocol The RFB protocol is a simple protocol for sending graphics to be displayed on a remote display or screen. RFB protocol places very little demand on the remote display in terms of processing power and memory demands since all processing is done at the server side. This protocol is a true thin client protocol because it has very low bandwidth requirements and shifts all processing demands to the RFB server instead of the RFB client (Kerai, 2010). The major interest in designing this protocol is to make very few requirements of the client in terms of processing (Richardson, 2010). The two remote endpoints in the RFB protocol are referred to as the RFB client or viewer and the RFB server (Baig et al., 2012). It works by simply taking rectangles of screen data from the RFB server with a given position and size and puts them into its frame buffer so that they appear in the correct place on the RFB client's screen (Masthan et al., 2013). Despite the fact that RFB protocol uses encrypted passwords and network, any communication over the network is vulnerable and can be attacked by a Man-In-The-Middle (MITM) by using a few tools and techniques (Kerai, 2010). Also, the applications of VNC which are developed based on RFB protocol are generally slower, offer fewer features and security options than Remote Desktop (RD) which is based on the RDP protocol (Masthan et al., 2013).