MODELLING AND SIMULATION OF FIELD EMISSION IN CARBON NANOTUBE BASED IONIZATION GAS SENSOR

Gas sensors are of main interest in the field of oil and gas industry. They are used to sense corrosive gases in the pipelines and leakage in the delivery system. One of the recently developed gas sensor that has become the focal point of research is the ionization gas sensor. This sensor technology is still in its infancy and much can be done to increase the efficiency of the sensor. In this research, a new model to study the gas detection mechanism of carbon nanotube (CNT) based ionization gas sensor has been developed. The model incorporates electron field emission property of the CNTs. The new model consists of three modules, i.e., CNT particle injection module, CNT density and aspect ratio variation module, and CNT velocity assignment module. These three modules are combined together and embedded in the standard Particle-In-Cell / Monte Carlo Collision (PIC-MCC) codes. The integrity of the enhanced PIC-MCC codes has been validated by calculating the field enhancement factor, β. Furthermore, the functionality of these codes is checked by running simulations of DC discharges in different gases and comparing the results with published experimental and simulated works. With the help of enhanced PIC-MCC codes the simulation of gas breakdown behavior with CNT field emission effects become possible for the first time. From the results, around one order of magnitude decrease in the breakdown voltages is observed when CNT is used in ionization gas sensor. The electrostatic screening effects are reduced to a minimum when inter-tube spacing is equal to the height of the CNT. Faster response time is also observed with the presence of CNT in ionization gas sensor. These results suggest that by properly controlling the growth of CNT structures, an optimized CNT based ionization gas sensor can be realized

International terrorism and its impact on civil freedoms in Iraq after 2003: A critical analysis of the right to life and personal security

Terrorism is one of the threats against which the international community, above all states, must protect their citizens. They have not only the right but also a duty to do so. States must take the greatest care to ensure that counter-terrorism does not become an all-embracing concept that could be used to justify violations of human rights. Many legal documents define terrorism as an organised system of intimidation with violence behaviour designed to generate fear in a community to accomplish the interests of certain individuals or groups, whether acting for or in opposition. The definition of terrorism is unclear, especially as the UN’s 1373 Resolution indicates a dual meaning of terrorism because one country’s terrorist can be another country’s freedom fighter and vice versa. This thesis revolves around the problems of lack of having a clear definition of the terms “international terrorism” and “terrorist acts” under the Iraqi Anti- Terrorism Act No. 13 of 2005 as well as the weaknesses of the international conventions on terrorism, which has made it difficult internationally to adopt a uniform standard in fighting terrorism. The main objective of this thesis is to analyse the impact of international terrorism on civil freedoms in Iraq after 2003 focusing mainly on the right to life and personal security by examining the Iraqi Anti-Terrorism Act No. 13 of 2005. In analysing the main objective of this thesis, one of the research questions posed is on the impact of international terrorism on civil freedoms that is, the right to life and personal security in Iraq after 2003. The methodologies adopted in this thesis are doctrinal legal research and empirical research approach. Based on the findings, the thesis concludes that the impact of international terrorism on civil freedoms in Iraq after 2003 has indeed affected the right to life and personal security. One of the recommendations put forward based on the findings is that, there is a need to amend/repeal the Iraqi Anti-Terrorism Act No. 13 of 2005 as far as the definitions of “international terrorism” and “terrorist acts” are concerned

A quest for defining terrorism in international law: The emerging consensus

The United Nations (UN) has no internationally-agreed definition of terrorism.The definitional impasse has prevented the adoption of a Comprehensive Convention on International Terrorism.Even in the immediate aftermath of 9/11 the UN failed to adopt the Convention, and the deadlock continues to this day. The prime reason is the standoff with the Organization of the Islamic Conference (OIC).The Arab Terrorism Convention and the Terrorism Convention of the Organization of the Islamic Conference defines terrorism to exclude armed struggle for liberation and self-determination.This increased its complexity and vagueness.The aim of this paper is to examine the definitional aspect of terrorism and the challenges faced in adopting a single universally accepted definition by the international community.The methodology adopted in this paper is purely a library based research focusing mainly on primary and secondary sources. The paper concludes that nations or states have to come to agreement on a definition of the term “terrorism”, for without a consensus of what constitute terrorism, nations or states could not unite against it.A general definition of terrorism is necessary in order for the international community to fight against terrorism in a precise way

Survey in Nuclear Magnetic Resonance Spectroscopy

Over the past fifty years nuclear magnetic resonance spectroscopy, commonly referred to as NMR, has become the preeminent technique for determining the structure of organic compounds. Of all the spectroscopic methods, it is the only one for which a complete analysis and interpretation of the entire spectrum is normally expected. Although larger amounts of sample are needed than for mass spectroscopy, NMR is non-destructive, and with modern instruments good data may be obtained from samples weighing less than a milligram. To be successful in using NMR as an analytical tool, it is necessary to understand the physical principles on which the methods are based. Keywords : NMR , spectra , spin , nuclear , magnetic , data.

Management System of Smart Electric Vehicles Using Software Engineering Model

In this paper, a management system for smart electric vehicle is introduced using software engineering models and installed Sensor Network (SN). Two software engineering models are proposed to construct information exchange and available resource management algorithms, in which the required performance of vehicles is obtained. The resource management algorithm adopts the LeNet-5 deep-learning model in choosing the best driving mode. The datset is achieved from the simulated sensor Network (SN). The results show the satisfied performance of the electric cars in terms of information exchange and resource management. The MQTT broker server is employed for monitoring the information exchange algorithm, where the delay time is less than 1 sec for transmitting 1000 message. The proposed system saves power by 1-8 Kwh and a storage capacity by 9-95 MB for driving 100Km

MODELLING AND SIMULATION OF FIELD EMISSION IN CARBON NANOTUBE BASED IONIZATION GAS SENSOR

Gas sensors are of main interest in the field of oil and gas industry. They are used to sense corrosive gases in the pipelines and leakage in the delivery system. One of the recently developed gas sensor that has become the focal point of research is the ionization gas sensor. This sensor technology is still in its infancy and much can be done to increase the efficiency of the sensor. In this research, a new model to study the gas detection mechanism of carbon nanotube (CNT) based ionization gas sensor has been developed. The model incorporates electron field emission property of the CNTs. The new model consists of three modules, i.e., CNT particle injection module, CNT density and aspect ratio variation module, and CNT velocity assignment module. These three modules are combined together and embedded in the standard Particle-In-Cell / Monte Carlo Collision (PIC-MCC) codes. The integrity of the enhanced PIC-MCC codes has been validated by calculating the field enhancement factor, β. Furthermore, the functionality of these codes is checked by running simulations of DC discharges in different gases and comparing the results with published experimental and simulated works. With the help of enhanced PIC-MCC codes the simulation of gas breakdown behavior with CNT field emission effects become possible for the first time. From the results, around one order of magnitude decrease in the breakdown voltages is observed when CNT is used in ionization gas sensor. The electrostatic screening effects are reduced to a minimum when inter-tube spacing is equal to the height of the CNT. Faster response time is also observed with the presence of CNT in ionization gas sensor. These results suggest that by properly controlling the growth of CNT structures, an optimized CNT based ionization gas sensor can be realized

BIOSORPTION AND RECOVERY OF HEAVY METALS FROM AQUEOUS SOLUTIONS BY EICHHORNIA CRASSIPES (WATER HYACINTH) ASH

Heavy metal’s release without treatment poses a significant threat to the environment. Heavy metals are non-biodegradable and persistent. In the present study the ash of water hyacinth (Eichhornia crassipes), was used to remove six metals from aqueous solutions through biosorption. Results of batch and column experiments showed excellent adsorption capacity. Removal of lead, chromium, zinc, cadmium, copper, and nickel was 29.83, 1.263, 1.575, 3.323, 2.984 and 1.978 µgg-1, respectively. The biosorptive capacity was maximum with pH >8.00. Desorption in µgg-1 of ash for lead, chromium, zinc, cadmium, copper, and nickel was 18.10, 9.99, 11.99, 27.54, 21.09, and 3.71 respectively. Adsorption/desorption of these metals from ash showed the potential of this technology for recovery of metals for further usages. Hydrogen adsorption was also studied with a Sievert-type apparatus. Hydrogen adsorption experiments showed significant storage capacity of water hyacinth ash

Comparison of Alternating Variable Search and Simple Methods of Optimisation for Inductively Coupled Plasma Optical Emission and Atomic Fluorescence Spectrometry

The performance of several cyclic alternating variable search (AVS) optimisation methods are compared with two simplex methods with respect to the number of changes of variable required to search a model two-factor response space. The roles of the initial step size and of the variable step size are discussed, and the information produced concerning the shape of the factor space is evaluated. An AVS method which starts with a fixed step size and then changes to a variable step size on second and subsequent cycles is compared with a variable step size simplex for the optimisation of an inductively coupled plasma optical emission spectrometer and of the atomiser, source inductively coupled plasmas in atomic fluorescence spectrometry (the ASIA system). The order in which the variables are taken in the AVS method does not affect the value of the optimum eventually found. Both methods perform satisfactorily for the optical emission work, although the AVS method provides information about the shape of the factor space which is easier to interpret than in the simplex method. However, the simplex method was not always able to satisfy the conditions for termination in the case of the atomic fluorescence studies and was much slower to implement than the AVS method as the latter used direct visual feedback from the output of the lock-in amplifier as a measure of the figure of merit (total fluorescence signal)

Robotic dry cleaner for photovoltaic solar panels: an implemented design that evaluated in iraq's weather

Arabian desert areas are suffered from high mitigation in the produced photovoltaic (PV) power due to high dusty weather. This article presents a robotic cleaner that will significantly reduce the impact of dust on the installed PV systems in these areas. The proposed robotic cleaner is simple, low cost, standalone, self-powered, portable, and connected to the cloud. ESP32 used as a controller that manages the cleaning process and monitors its PV power production, the battery's state of charge, time of the day, and weather conditions. Thanks to the ESP32 features and its ability to connect to the cloud, as an internet of things (IoT), via the ThingSpeak website. All the electrical, mechanical, and electronic design aspects are presented and implemented in this article. The results show the effectiveness and performance enhancement due to periodic cleaning using the proposed robotic cleaner. The results also show that the total percentage of the monthly normalized accumulated losses for the two scheduled cleaning photovoltaic strings with a performance improvement of 15.54% for the weekly cleaned string (WCS) 83.04% for the never cleaned string (NCS) through the tested month

Constrictive Pericarditis Presenting as Bilateral Pleural Effusion: A Report of Two Cases

Constrictive pericarditis is a rare presentation. We need a very high index of clinical suspicion to diagnose the disease. It most commonly presents secondary to tuberculosis (TB) in the developing world and post-radiation therapy in the developed world. Classically, it presents with symptoms of heart failure and as pericardial thickening or calcification on imaging studies. In hospital settings, constrictive pericarditis is not usually considered as a differential in patients presenting with pleural effusion. According to the literature, associated pleural effusions in cases of constrictive pericarditis could be left-sided. Herein, we present two unusual presentations of cases with bilateral pleural effusions. One of our cases developed constrictive pericarditis with concurrent active tuberculosis. This is a rare presentation because, normally, constrictive pericarditis is a late complication of tuberculosis. We suggest that when dealing with cases of bilateral pleural effusion, the etiology of constrictive pericarditis should be considered