Model ingredients and peak mass production in heavy-ion collisions

We simulate the central reactions of $^{20}$Ne+$^{20}$Ne, $^{40}$Ar+$^{45}$Sc, $^{58}$Ni+$^{58}$Ni, $^{86}$Kr+$^{93}$Nb, $^{129}$Xe+$^{118}$Sn, $^{86}$Kr+$^{197}$Au, and $^{197}$Au+$^{197}$Au at different incident energies for different equations of state, different binary cross sections and different widths of Gaussians. A rise-and-fall behavior of the multiplicity of intermediate mass fragments (IMFs) is observed. The system size dependence of peak center-of-mass energy E$_{c.m.} ^{max}$ and peak IMF multiplicity $^{max}$ is also studied, where it is observed that E$_{c.m.}^{max}$ follows a linear behavior and $^{max}$ shows a power-law dependence. A comparison between two clusterization methods, the minimum spanning tree and the minimum spanning tree method with binding energy check (MSTB), is also made. We find that the MSTB method reduces the $^{max}$, especially in heavy systems. The power-law dependence is also observed for fragments of different sizes at E$_{c.m.} ^{max}$ and the power-law parameter $\tau$ is found to be close to unity in all cases except A$^{max}$.Comment: 6 Figures, 7 page

Development of Highly Active Ligands for Copper Catalyzed Atom Transfer Radical Processes

This dissertation focuses on the ligand design for atom transfer radical processes and direct reduction method. Atom transfer radical processes such as addition (ATRA), polymerization (ATRP) and cyclization (ATRC) are the fundamental organic reactions in which addition of alkyl halide via free radical means results in the formation of monoadducts or polymers. We have designed tris(2-pyridylmethyl)amine based ligands for ATRP, where systematic addition of the electron donating groups on the pyridine rings of TPMA, resulted in formation of three ligands; TPMA*1, TPMA*2 and TPMA*3. As indicated by electrochemical studies, a nearly stepwise decrease (DE~60 mV) of E1/2 values on going from [CuII(TPMA)Br][Br] to [CuII(TPMA*3)Br][Br], confirming that the presence of electron donating groups increased the reducing ability of the corresponding copper(I) complexes. The complexes were utilized for Activator Regenerated by Electron Transfer (ARGET) ATRP, the preliminary results indicated that the TPMA*2 ligand could have a higher future potential in copper catalyzed ATRP than TPMA*1 and TPMA*3. Secondly, a series of mononuclear mixed ligand copper(II) complexes with deprotonated L-amino acids (aa = glycine, alanine, phenylalanine and proline) and bidentate N-based ligands (NN = 1, 10-phenanthroline, 2, 2\u27-bipyridine), [CuII(aa)(NN)Cl] were originally designed for ATRA. However, these complexes were successfully utilized as precursors for the synthesis of copper(I) cyanide (CuCN) coordination polymers via direct reduction method. This method has provided an efficient alternative to traditionally used solvo- and hydrothermal methods, where [CuII(aa)(NN)Cl] complexes activated the cyanide functionality of the diazo radical initiator, 2, 2′-azobis(2-methylpropionitrile) (AIBN) to synthesize multi-dimensional CuCN polymers. We observed that the dimensionality of the polymers was dependent on the structure of the ligand. One-dimensional (1D) polymers were exclusively formed with the aromatic N-based ligands whereas two- (2D) and three-dimensional (3D) frameworks were synthesized with aliphatic amines. We have observed that the ligand design has successfully regulated the size of the pores along with dimensionality. The work in this dissertation provided a significant contribution in two different fields; homogenous catalysis and material synthesis. With the help of the ligand design, we were able to understand as well as regulate the atom transfer radical processes and direct reduction method

N-DOPED MULTIWALLED CARBON NANOTUBES: FUNCTIONALIZATION, CHARACTERIZATION AND APPLICATION IN LI ION BATTERIES

The focus of this dissertation is to utilize chemical functionalization as a probe to investigate the reactivity of N-doped multiwalled carbon nanotubes (N-MWCNTs). The surface of N-MWCNTs, being a set of potentially reactive graphene edges, provides a large number of reactive sites for chemical modification, so considerable changes in chemical and physical properties can be envisaged. We observed that both reduction (dissolving metal reduction/alkylation) and oxidation (H2SO4/HNO3 and H2SO4/KMnO4 mixtures) of N-MWCNTs lead to formation of interesting spiral channels and spiraled carbon nanoribbons. A variety of techniques, including TGA, SEM, TEM, XRD and surface area measurements were used to analyze these new textural changes. We have developed methods to demonstrate that specific chemistry has occurred on these new structures. To this end, we introduced metal-binding ligands that could be used as probes in imaging and spectroscopic techniques including TEM, STEM, EDX, and EELS. A proposal for the underlying structure of N-MWCNTs responsible for the formation of the new textures is presented. We have investigated the performance of our materials as potential negative electrodes for rechargeable lithium ion batteries

Wireless communication with mobile inspection robots while submerged inside oil storage tanks

Data acquisition during storage tank inspection is one of the most important aspects for petrochemical storage tank owners. Mobile inspection robots designed to enter inside a storage tank without taking the tank out of service are required to enter through manholes on the roof of the tank with openings as small as 300-millimetre diameter. These robots are controlled via an umbilical cable which supplies power to the robot, sends and receives signals to control robot motion, and transfers inspection data acquired by non-destructive testing (NDT) sensors back to NDT inspectors. It is important to localize a robot inside the tank so that NDT data indicating a defect such as corrosion pitting in tank floors or weld cracks can be mapped for subsequent monitoring and repair. Wireless communication with the robot for NDT data acquisition and localization would enable the minimization of umbilical size and its effective management which is important when a small mobile robot is supplied with a very long umbilical. This paper presents results of a study to develop a wireless communication system that uses radio frequency (RF) signals with low power (<1W) sent by a transceiver on a robot operating inside an oil storage tank which travel through an oil medium, are transmitted through steel tank walls and are captured by receivers placed in air outside the tank. Simulations using Feko software have been performed to assess the feasibility of using RF for communication in oil storage tanks with laboratory experiments conducted using vegetable oil to validate the simulations. RF signals transmitted by a robot operating inside an oil tank and received by a number of receivers placed in air around the tank has potential application as a robot localization system

Probiotics. Going on the natural way.

Science is providing us the tools to diagnose and treat the infection before it causes damage. For some decades now, bacteria known as probiotics have been added to various foods because of their beneficial effects for human health. It comprises knowledge of the relationship between diet and health and the effects of food ingredients on physiological functions and health. Probiotics are commonly consumed as part of fermented foods with specially added active live cultures; such as in yogurt or as dietary supplements. The potential application of probiotics for oral health has recently been the focus of attention for various health researchers. The number of products containing probiotics entering the market is increasing. These products usually contain streptococci, lactobacilli or bifidobacteria. The application of probiotic strategies may, in near future provide an end to many infections occurring in oral cavity. This article summarizes the currently available data on the potential benefits of probiotics for oral health and potential risks associated with them

Electron beam diagnosis for weld quality assurance

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University London.Electron beam welding is used for fabricating critical components for the aerospace and nuclear industries which demand high quality. The cost of materials and associated processes of fabrication is also very high. Therefore, manufacturing processes in these industries are highly controlled. However, it has been found that even minor changes in the electron beam gun itself can produce large variations in beam characteristics, leading to unpredictable welding performance. Hence, it is very important to ensure the beam quality prior to carrying out welds. This requires some kind of device and process to characterise the electron beam to indicate variations. A detailed review of different technologies used to develop devices to characterise electron beams has been carried out. At this time, it is uncommon for beam measurement to be carried out on production EBW equipment. Research carried out for this thesis is focused on development of a novel approach to characterise the electron beams using a slit-probe to maintain the quality of the welds. The challenge lies in deriving relevant features from the acquired probe signal which can effectively differentiate between the beams of different quality. Wavelet transformation, with its advantages over other methods for simultaneous time and frequency localization of signals, has found its application to feature extraction in many pattern based classifications. This technique has been used to analyse probe signals considering that different quality beams will possess unique signal profiles in the form of their distribution of energies with respect to frequency and time. To achieve the aim of the thesis, an experimental approach was used by carrying out melt runs on Ti-6Al-4V plates focusing on aerospace requirements, and varying beam properties and acquiring probe signals for all beam settings. Extracted features from the probe signals have been used in classification of the electron beams to ensure these will produce welds within the tolerance limits specified by aerospace standards for quality assurance. The features vector was compiled following statistical analysis to find the significant beam characteristics. By analysing the performance of classifier for different combination of parameters of the features vector, the optimum classification rate of 89.8% was achieved by using the parameters derived from wavelet coefficients for different decomposition levels. This work showed that the use of wavelet analysis and classification using features vectors enabled identification of beams that would produce welds out-of-tolerance. Keywords: Electron beam welding, probe devices, electron beam characterisation, quality assurance, wavelet transform, features vector, linear discriminant classifier, weld profiles, weld defects.Brunel University and The Welding Institute (TWI

Rechargeable Batteries Including High-Voltage Cathode and Redox Shuttle Conferring Overcharge Protection

Compounds for use as photoredox catalysts and as redox shuttles in a rechargeable battery having a high-voltage cathode providing overcharge protection capabilities are provided, including a compound according to the formula: (see patent for formula) wherein R is selected from the group consisting of alkyl, aryl, alkylaryl, alkoxyaryl, alkylcarboxyl, aryl carbonyl, haloalkyl, perfluoroalkyl, glycols, haloaryl, a negative electrolyte, and a polymer