Significant economic impact may be caused by the deterioration of the power quality supplied to the sensitive and expensive industrial loads. Monetary losses can be in the form of decrease in production as well as damage to industrial equipment caused by voltage related problems. Dynamic Voltage Restorers (DVR) are considered as one of the most efficient and advisable solutions that can alleviate the dynamic power quality problems. In this paper comparison of various topologies of DVR is made, with the further implementation of DVR with energy storage unit. Elaboration of the relevant control technique for voltage compensation is carried out. The results of extensive simulations in MATLAB/ SIMULINK are provided to demonstrate the effectiveness of the DVR for ensuring the power quality in response to grid disturbances.
This paper proposes a new mathematical tool to optimize controllers in the frequency domain. The new tool is much faster and less computationally intensive compared to time-integral criteria (i.e ITAE). The outcome of this research is a set of mathematical formulae that calculate optimal PID settings as a function of plant's parameters. Finally, the obtained tuning rules are tested in an application study.
In this paper, one of the recent techniques of sliding mode control (SMC), namely fullorder SMC, is applied to a nonlinear quarter car suspension model that belongs to a class of second-order nonlinear uncertain systems. The governing equations of the model are derived based on force analysis. Moreover, the full-order control law is designed to satisfy the design requirements of preventing damage and providing human comfort. Finally, the effectiveness of the proposed control is illustrated through a numerical example.
TiO2 and Cu-TiO2 thin films were deposited by e-beam evaporation and then annealed at 350 and 500?C. Film properties were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The catalytic activity was tested by monitoring the discoloration under visible light of methylene blue (MB) pre-adsorbed on the films and degradation of 2-propanol under simulated solar light in a gas phase batch reactor. Cu-doped films resulted the most reactive samples during the degradation of MB under visible radiation, whereas the rate of photodegradation of 2-propanol was the highest in pure TiO2 films due to the greater crystallinity and less electron-hole recombination phenomena.
In this study, we measured the solubility of carbon dioxide in three deep eutectic solvents (DES), (Choline chloride + Monoethanolamine, Ch-M), (Choline chloride + Diethanolamine, Ch-D) and (Choline chloride + Methyldiethanolamine, Ch-MD), for three different choline chloride:amine molar ratios of 1:6, 1:7 and 1:8. The CO2 absorption was conducted with a solvent screening set-up (SSS) and the CO2 loading was measured with a total organic carbon (TOC) analyzer. The solubility experiments were performed based on the conditions of the absorber in the post-combustion capture process (PCO2 = 15kPa and T = 40oC). Thereafter, qualitative and quantitative analysis with FTIR and HPLC were conducted to determine the extent of chemical and physical CO2 absorption. Results revealed that amine-based DESs have absorption capacity that is comparable to pure amines . The solubility of CO2 was found to increase as the molar ratio of the amine in the DES increased.
Elemental sulfur is recovered through Claus process in oil and gas industry from gas streams rich in H2S. Several contaminants in H2S Claus feed, lead to large polycyclic aromatic hydrocarbons (PAHs) and soot formation causing catalyst deactivation. Catalyst replacement increases sulfur production cost. Thus, PAHs and soot formation should be inhibited by understanding more the reactions responsible for them. In this work, a detailed reaction mechanism for PAHs growth through its armchair site mediated by methyl radicals' addition is studied. The reaction is modelled using phenanthrene with an armchair site as the reactant and pyrene as the product. The chemically accurate energetics and molecular parameters for all the species involved are determined through quantum calculations. The rate constants are evaluated using transition state theory. Based on these calculations and potential energy diagrams, the energetically favored pathways for the formation and growth of aromatic hydrocarbons in Claus furnace are presented.
Electrokinetic Low-concentration acid IOR (EK LCA-IOR) is one of the emerging IOR technologies, which involves the application of the Low-concentration acidizing integrated with electrically enhanced oil recovery (EK-EOR).This research focusses on analyzing the effectiveness of the EK LCA-IOR process in Abu Dhabi carbonates, improving the capillary number and enhancing depth of penetration. Core-flood tests were conducted at reservoir conditions and correlations have shown that the application of EK LCA-IOR, provided an additional 17-28% oil recovery as compared to waterflooding. In addition, EK LCA-IOR also improves the capillary number by 500%- 1500%, mainly due to a decrease in interfacial tension. SECTS results indicate that EK LCA-IOR precisely delivers the acid front to penetrate 60% of core-length. This study takes one step forward towards the development of EK Low-concentration acid IOR method feasible for Abu Dhabi oil fields in order to make smart waterfloods applicable for complex fractured reservoirs of UAE.
Cloud computing is a very promising technology. It became popular at a short period of time since it can serve people, organizations, companies, institutes, governments and much more. At the same time, technology doesn't stop as it keeps improving every single day. As a result digital crime became popular due to this improvement. Despite cloud computing advantages, it can represent a challenge and cause problems if it suffers a breach. Cloud forensics is a new forensic filed that apply the digital forensics in cloud computing, and due to its new age, cloud forensics encounter different types of challenges that can be categorized into technical, legal, and organizational challenges. This paper proposes solutions to both technical and legal issues that cloud forensics is facing.
The rapid technology evolution dramatically changed the users experience and reshaped the current electronic systems functionality. Gaming consoles are categorized as small scale digital devices and have evolved from just being restricted to gaming to perform computing functionality such as storing images, creating videos, accessing Internet, and watching movies. With this dramatic change in functionality, the usage of gaming console devices in criminal activities have increased; however it's still considered a vague area for today's forensic examiners. This paper highlights the challenges faced during gaming console forensic analysis and exemplifies the lack of reliable specialized forensic tools. A framework was developed to examine the current state of existing forensic acquisition and analysis tools, by exploring their applicability to gaming console engines, employing two gaming consoles Xbox-one and PlayStation-4; validating the acquired images, comparing retrieved artifacts before and after restoring the console to the factory settings, and conducting network analysis.
Cloud Storage services keep increasing in popularity as users are increasingly depending on storing data in the cloud using small scale digital devices due to the: ease of access and cost effectiveness of those services, as a consequence, an expansion is occurring in the field of cloud forensics. As a case study, three Cloud storage applications were used: Dropbox, OneDrive, and Google Drive to investigate and analyze artefacts remaining on iPad and Samsung tablets from accessing those applications. It was found that the artefacts recovered are of significant forensic value and can be used as potential evidence in the cloud forensics process concerning the client side.
