69 research outputs found

    Molecular Investigations on the Behaviours of Surface-Active Materials

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    This thesis applied molecular dynamics techniques, a powerful method based on factual observations at nanoscales, to effectively understand macroscopic and microscopic behaviors of surface-active materials in biphasic systems. First, few works have been focused on revealing the effect of naturally occurring organic materials such as naphthenic acids on the behaviors of polyaromatic compounds (known as asphaltenes that are interfacially active) during oil production. To bridge this gap, a series of MD simulations were performed to investigate the effects of molecular structures. It was revealed that naphthenic acids, depending on the solvent type, can either hinder or enhance nano-aggregation among asphaltene molecules. Furthermore, they can affect the orientations of polyaromatic molecules at the oil/water interface. The second direction of this thesis investigated biphasic systems in daily life, i.e., wastewater containing soap. The results obtained shed light on fundamental understandings and utilizations of surface-active materials during industrial applications and in our daily life

    Biopolymers from Natural Resources

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    This work covers all aspects related to the obtainment, production, design, and processing of biopolymers obtained from natural resources. Moreover, it studies characteristics related to the improvement of their performance to increase their potential application at an industrial level, in line with the concept of a global circular economy. Thus, this work firstly classifies biopolymers obtained from natural resources (e.g., biobased building blocks and biopolymers extracted directly from plants and biomass), and then summarizes several cutting-edge research works focused on enhancing the performance of biopolymers from natural resources to extend their application in the industrial sector, and contribute to the transition to more sustainable plastics

    Membranes for Water and Wastewater Treatment

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    Water is a vital element for life and the environment. Water pollution has been documented as a contributor to a wide range of health problems. In recent years, the water quality levels have suffered great deterioration because of rapid social and economic development and because it is used to “dump” a wide range of pollutants.This book entitled “Membranes for Water and Wastewater Treatment” contains featured research papers dealing with recent developments and advances in all aspects related to membranes for water and wastewater treatment: membrane processes, combined processes (including one membrane step), modified membranes, new materials, and the possibility to reduce fouling and to improve the efficiency of enhanced processes. The papers compiled in this Special Issue can be read as a response to the current needs and challenges in membrane development for water and wastewater treatment.Half of the research articles correspond to concrete and practical applications of the use of membrane processes in different fields of the industry, with the aim of treating and conditioning water and wastewater. The studies reveal the treatment of industrial streams, mining, recycled paper industry, olive mill, urban wastewater, etc. Another important percentage of studies are related to membrane modification processes, with the aim of obtaining new materials with better performance in the separation processes, thus describing the use of membranes modified with chitosan, nanoparticles, and other organic compounds. This field also includes studies related to fouling and its modeling

    Modeling and Simulation of Polymerization Processes

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    This reprint is a compilation of nine papers published in Processes, in a Special Issue on “Modeling and Simulation of Polymerization Processes”. It aimed to address both new findings on basic topics and the modeling of the emerging aspects of product design and polymerization processes. It provides a nice view of the state of the art with regard to the modeling and simulation of polymerization processes. The use of well-established methods (e.g., the method of moments) and relatively more recent modeling approaches (e.g., Monte Carlo stochastic modeling) to describe polymerization processes of long-standing interest in industry (e.g., rubber emulsion polymerization) to polymerization systems of more modern interest (e.g., RDRP and plastic pyrolysis processes) are comprehensively covered in the papers contained in this reprint

    Brain and Human Body Modeling

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    This open access book describes modern applications of computational human modeling with specific emphasis in the areas of neurology and neuroelectromagnetics, depression and cancer treatments, radio-frequency studies and wireless communications. Special consideration is also given to the use of human modeling to the computational assessment of relevant regulatory and safety requirements. Readers working on applications that may expose human subjects to electromagnetic radiation will benefit from this book’s coverage of the latest developments in computational modelling and human phantom development to assess a given technology’s safety and efficacy in a timely manner. Describes construction and application of computational human models including anatomically detailed and subject specific models; Explains new practices in computational human modeling for neuroelectromagnetics, electromagnetic safety, and exposure evaluations; Includes a survey of modern applications for which computational human models are critical; Describes cellular-level interactions between the human body and electromagnetic fields

    Understanding enhanced oil recovery (EOR) in sandstone reservoirs: the role of redox changes in clay minerals on wettability

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    A great body of research has been focused on understanding enhanced oil recovery in mature sandstone reservoirs. The benefit of further producing such mature fields is indisputable since the natural-driven oil recovery of the oil initially in place can vary from <5% to 50%, in the best-case scenario. The enhanced oil recovery methods, such as CO2 injection, steam injection, surfactant injection etc., have been established through the years, with researchers proposing mechanisms that can explain the additional oil recovery. The following pages of this thesis explore in more detail the low salinity water flooding (LSWF), a method that has gained significant ground the recent years, due to the low costs of implementation. Many mechanisms have been proposed since the 1950's, when first observations were made, with more light being shed since the late 1990's, continuously to present day. The experimental work of this PhD project focused on examining reduction-oxidation (redox) processes during oil recovery upon EOR implementation. This was approached by using iron-bearing clay minerals, with various iron content, as proxies of iron phases present in the reservoir rock. First, the wettability of those clay minerals, such as natural occurring nontronite and illite, was explored via clay mineral films, measuring the contact angle of crude oil and DI water, under reduced and oxidised conditions, with reduced clay films, exhibiting more water-wet surfaces. Then, the hydration and structural changes of a nontronite clay mineral was established with infrared spectroscopy (IR). At these experiments, the saturating cation was manipulated by clay mineral treatment, acquiring homoionic Na+, Ca2+ and K+ samples of nontronite, allowing the isolation of hydration effects and other clay mineral / cation interactions. Those IR measurements revealed a more hydrated state under partial reduction, and stronger clay mineral/ cation interaction under (partially) reduced conditions (N-IR, M-IR). Significant spectral alterations were also observed at the F-IR range, upon clay mineral reduction, with minimum effects due to cation saturation and relative humidity induced. Lastly, the thermodynamics of cation exchange reactions, using two Na+-saturated nontronites and a Na+-saturated montmorillonite, was attempted to be quantified. Two different reactions were considered for all three minerals: clay mineral- Na-->Ca and Na-->K. These experiments, conducted under fully reduced conditions, showed that the inverse of the Na-->Ca reaction is favoured (Ca favoured with ΔG <0), which supports the basic theory of LSWF, as sodium is considered a key factor for LSWF positive effect, but also how cation exchange, under such redox conditions, are exhibiting hysteresis, a key observation for better understanding such processes on clay minerals, across disciplines

    Case series of breast fillers and how things may go wrong: radiology point of view

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    INTRODUCTION: Breast augmentation is a procedure opted by women to overcome sagging breast due to breastfeeding or aging as well as small breast size. Recent years have shown the emergence of a variety of injectable materials on market as breast fillers. These injectable breast fillers have swiftly gained popularity among women, considering the minimal invasiveness of the procedure, nullifying the need for terrifying surgery. Little do they know that the procedure may pose detrimental complications, while visualization of breast parenchyma infiltrated by these fillers is also deemed substandard; posing diagnostic challenges. We present a case series of three patients with prior history of hyaluronic acid and collagen breast injections. REPORT: The first patient is a 37-year-old lady who presented to casualty with worsening shortness of breath, non-productive cough, central chest pain; associated with fever and chills for 2-weeks duration. The second patient is a 34-year-old lady who complained of cough, fever and haemoptysis; associated with shortness of breath for 1-week duration. CT in these cases revealed non thrombotic wedge-shaped peripheral air-space densities. The third patient is a 37‐year‐old female with right breast pain, swelling and redness for 2- weeks duration. Previous collagen breast injection performed 1 year ago had impeded sonographic visualization of the breast parenchyma. MRI breasts showed multiple non- enhancing round and oval shaped lesions exhibiting fat intensity. CONCLUSION: Radiologists should be familiar with the potential risks and hazards as well as limitations of imaging posed by breast fillers such that MRI is required as problem-solving tool

    Characterization of alar ligament on 3.0T MRI: a cross-sectional study in IIUM Medical Centre, Kuantan

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    INTRODUCTION: The main purpose of the study is to compare the normal anatomy of alar ligament on MRI between male and female. The specific objectives are to assess the prevalence of alar ligament visualized on MRI, to describe its characteristics in term of its course, shape and signal homogeneity and to find differences in alar ligament signal intensity between male and female. This study also aims to determine the association between the heights of respondents with alar ligament signal intensity and dimensions. MATERIALS & METHODS: 50 healthy volunteers were studied on 3.0T MR scanner Siemens Magnetom Spectra using 2-mm proton density, T2 and fat-suppression sequences. Alar ligament is depicted in 3 planes and the visualization and variability of the ligament courses, shapes and signal intensity characteristics were determined. The alar ligament dimensions were also measured. RESULTS: Alar ligament was best depicted in coronal plane, followed by sagittal and axial planes. The orientations were laterally ascending in most of the subjects (60%), predominantly oval in shaped (54%) and 67% showed inhomogenous signal. No significant difference of alar ligament signal intensity between male and female respondents. No significant association was found between the heights of the respondents with alar ligament signal intensity and dimensions. CONCLUSION: Employing a 3.0T MR scanner, the alar ligament is best portrayed on coronal plane, followed by sagittal and axial planes. However, tremendous variability of alar ligament as depicted in our data shows that caution needs to be exercised when evaluating alar ligament, especially during circumstances of injury

    Archaeometry: an Australasian perspective / edited by W. Ambrose, P. Duerden.

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