Investigating the thermal behavior differences between beet and cane sugar sources

The melting behavior of sucrose has been well studied over a long period of time. However, one aspect that needed further study was the wide variation in melting temperature reported in the literature for sucrose, as well as other simple sugars (e.g., glucose and fructose). Based on previous work carried out in the Schmidt laboratory, the initial loss of crystalline structure in sucrose, glucose, and fructose was attributed to thermal decomposition, rather than thermodynamic melting. Recently, a number of sucrose samples were investigated in the Schmidt laboratory and a marked difference in the thermal behavior of beet versus cane sucrose samples was observed. In general, sucrose from sugarcane sources exhibited two endothermic peaks in the DSC thermogram, one small peak proceeded by one large peak; whereas, sucrose from sugarbeet sources exhibited only one large endothermic peak. The thermal behavior of both beet and cane sucrose sources also exhibited heating rate dependency, with Tmonset values for both small and large peaks increasing as heating rate increased. Overall, however, the degree of thermal stability, based on results from an ampule heating study, was much greater for beet compared to cane sucrose sources. To date, no published research was found relating the presence and magnitude of the small endothermic DSC peak to the plant source of the sucrose – suagrbeet versus sugarcane. Thus, the main objective of this research was to identify the cause and underlying mechanism of the presence of the small endothermic DSC peak in cane sucrose sources. A variety of analytical methods and techniques were applied to approach this research objective, including moisture content analysis, pH, conductivity ash content, total sulfite content measurements, single crystal X-ray diffraction (SXRD), X-ray Micro-Computed Tomography (MicroCT), Differential Scanning Calorimetry (DSC), High Performance Liquid Chromatography (HPLC), and Confocal Raman imaging and spectroscopy. From this study we found that the pH, conductivity ash, and moisture content values varied widely within and between sugar sources, and were not able to explain the small endothermic DSC peak difference between beet and cane sucrose sources. However, impurities in the mother liquor occlusions in beet, Chinese cane, and Sugar in the Raw appear to play a major role in thermally stabilizing the sucrose molecule. Beet and Chinese cane sucrose sources contained residual sulfite from the sulfitization processing step; whereas, analytical and commercial cane sources, which usually do not undergo sulfitization, were below the detection limit. Thus, sulfite content appears to explain the absence of the small endothermic DSC peak. Also, by addition of different concentrations of potassium sulfite, we were able to control the thermal behavior of laboratory-recrystallized Sigma sucrose, demonstrating that low concentrations of sulfite can completely inhibit the small endothermic DSC peak in cane sources. In the case of Sugar in the Raw, the high conductivity ash and pH appear to be responsible for inhibition of the small endothermic DSC peak. Overall, this research reveals that the composition and chemistry of the mother liquor occlusions, formed within the sucrose crystal during the crystallization process, are responsible for the thermal behavior of the various sucrose sources studied herein, In addition, this study makes a substantial contribution to the investigation of the thermal behavior of crystalline sucrose at the molecular level, since no previous research was found that explored the internal crystalline structure and vibrational modes of “as is” and heated crystalline beet and cane sucrose sources, which were examined using Micro-CT and Confocal Raman imaging and spectroscopy, respectively. Overall, this research provides a comprehensive and more detailed understanding of the thermal behavior of sucrose, regardless of its source, which, in turn, is critical to the processing of and reactions in sucrose containing foods, such as baking and caramelization

A review of developments in carbon dioxide storage

Carbon capture and storage (CCS) has been identified as an urgent, strategic and essential approach to reduce anthropogenic CO2 emissions, and mitigate the severe consequences of climate change. CO2 storage is the last step in the CCS chain and can be implemented mainly through oceanic and underground geological sequestration, and mineral carbonation. This review paper aims to provide state-of-the-art developments in CO2 storage. The review initially discussed the potential options for CO2 storage by highlighting the present status, current challenges and uncertainties associated with further deployment of established approaches (such as storage in saline aquifers and depleted oil and gas reservoirs) and feasibility demonstration of relatively newer storage concepts (such as hydrate storage and CO2-based enhanced geothermal systems). The second part of the review outlined the critical criteria that are necessary for storage site selection, including geological, geothermal, geohazards, hydrodynamic, basin maturity, and economic, societal and environmental factors. In the third section, the focus was on identification of CO2 behaviour within the reservoir during and after injection, namely injection-induced seismicity, potential leakage pathways, and long-term containment complexities associated with CO2-brine-rock interaction. In addition, a detailed review on storage capacity estimation methods based on different geological media and trapping mechanisms was provided. Finally, an overview of major CO2 storage projects, including their overall outcomes, were outlined. This review indicates that although CO2 storage is a technically proven strategy, the discussed challenges need to be addressed in order to accelerate the deployment of the technology. In addition, beside the necessity of techno-economic aspects, public acceptance of CO2 storage plays a central role in technology deployment, and the current ethical mechanisms need to be further improved

A Guide to Additive Manufacturing

This open access book gives both a theoretical and practical overview of several important aspects of additive manufacturing (AM). It is written in an educative style to enable the reader to understand and apply the material. It begins with an introduction to AM technologies and the general workflow, as well as an overview of the current standards within AM. In the following chapter, a more in-depth description is given of design optimization and simulation for AM in polymers and metals, including practical guidelines for topology optimization and the use of lattice structures. Special attention is also given to the economics of AM and when the technology offers a benefit compared to conventional manufacturing processes. This is followed by a chapter with practical insights into how AM materials and processing parameters are developed for both material extrusion and powder bed fusion. The final chapter describes functionally graded AM in various materials and technologies. Throughout the book, a large number of industrial applications are described to exemplify the benefits of AM

Gas Turbines

This book is intended to provide valuable information for the analysis and design of various gas turbine engines for different applications. The target audience for this book is design, maintenance, materials, aerospace and mechanical engineers. The design and maintenance engineers in the gas turbine and aircraft industry will benefit immensely from the integration and system discussions in the book. The chapters are of high relevance and interest to manufacturers, researchers and academicians as well

The properties and crystallization behaviour of photo-degraded polypropylene

PhD ThesisPhoto-oxidatative degradation in isotactic polypropylene (PP) has been examined in samples made by both injection and compression moulding and using different moulding conditions. Samples were exposed to ultraviolet (UV) radiation in the laboratory for periods up to 48 weeks. The specimens were tested in tension and the fracture surfaces were inspected by scanning electron microscopy. The extent of chemical degradation was assessed by gel permeation chromatography and Fourier transform infrared spectroscopy. The structural characterization of the as-moulded and UV-exposed materials was conducted by differential scanning calorimetry, X-ray diffraction, pole figure analysis, and polarized light microscopy. Filled grades of PP containing talc were also investigated. The mechanical properties of degraded PP were shown to be highly dependent on aspects like the extent and depth-profile of degradation, the character of the polymer physical structure, and the presence of filler and nucleating agent. Injection moulded bars containing weld lines were also investigated, and their mechanical properties were generally poorer than those for equivalent samples without weld regions. With most samples studied here a partial recovery in tensile properties was observed after 6-9 weeks exposure. Analysis of the fracture surfaces indicated that in the specimens with better properties the surface cracks did not propagate into the undegraded interior. An increase in the polymer crystallinity was observed during exposure, caused by rearrangement of molecule segments released by oxidative scission in the non-crystalline region. This process, called chemi-crystallization, continues until a large number of chemical defects is present within the molecules, and it results in surface cracks formed spontaneously during exposure. In injection moulded samples the pattern of surface cracks featured circular arcs radiating from the injection gate and they were correlated with the flow lines generated during mould filling. The concentration of surface cracks in these samples varied with the location in the test bar, according to local variations in crystal orientation. The crystallization of photodegraded PP from the melt was investigated under isothermal and non-isothermal conditions. The kinetics of crystallization, degree of crystallinity, and morphology were shown to depend on the molecular weight and on the presence of chemical impurities within the molecules. The crystal y-phase was formed in specimens exposed for more than 18 weeks. Double peaks were normally observed in DSC heating experiments of unfilled polypropylene and were assigned to crystal re-organization during heating. The existence of different molecule species was detected by DSC and light microscopy, and might also have contributed to the melting behaviour.CAPES, Brazilian government

A Guide to Additive Manufacturing

This open access book gives both a theoretical and practical overview of several important aspects of additive manufacturing (AM). It is written in an educative style to enable the reader to understand and apply the material. It begins with an introduction to AM technologies and the general workflow, as well as an overview of the current standards within AM. In the following chapter, a more in-depth description is given of design optimization and simulation for AM in polymers and metals, including practical guidelines for topology optimization and the use of lattice structures. Special attention is also given to the economics of AM and when the technology offers a benefit compared to conventional manufacturing processes. This is followed by a chapter with practical insights into how AM materials and processing parameters are developed for both material extrusion and powder bed fusion. The final chapter describes functionally graded AM in various materials and technologies. Throughout the book, a large number of industrial applications are described to exemplify the benefits of AM

Unveiling the nature of dark matter with direct detection experiments

The desire of discovery is an anthropic need which characterises and connects the human being over the eras. In particular, observing the sky is an instinctive drive exerted by the curiosity of the mysteries which it retains. At the present time, the tremendous advances in the exploration of space have opened even more challenges than back in the days. One of the most urgent question is unveiling the nature of dark matter (DM). As stated by Neta A. Bahcall (Professor at Princeton University), "Cosmology has revealed an amazing universe, filled with a "dark sector" that composes 95% of the energy density of our cosmos [...]" (Dark matter universe, PNAS, 2015). About one-third of this dark sector is associated to an invisible and still undetected form of matter, the so-called dark matter, whose gravitational effect manifests at all cosmological scales. Both theoretical and experimental observations based on ordinary gravity reinforced the evidences for the existence of DM, since its first appearance in the pioneering calculations of F. Zwicky (1933). This PhD project explores the hypothesis that DM is made of new particles beyond the standard model. More specifically, it focuses on those DM particles which are trapped into the galactic gravitational field and populate the galactic halo. If DM interacts with ordinary particles, extremely sensitive detectors operating in very low-background environments, are expected to detect galactic DM particles scattering off their target material. This widely employed experimental technique is known as DM direct detection and it is the focus of my studies, where I consider the further hypothesis that DM interacts with atomic nuclei. The research I conducted during my PhD program consists of two main parts: the first part focused on purely phenomenology aspects of the DM direct detection (namely on the DM annual modulation treated using a non-relativistic effective theory and on the scattering of spin-1 DM particles off polarised nuclei) and the second one is more closely connected to experimental applications. The latter has been strongly stimulated by my collaboration with the two DM direct detection experiments CRESST and COSINUS.\ua0 For CRESST, I compute the DM-nucleus cross-section for the conventional spin-dependent interactions, used to analyse the data collected with a prototype Li-based detector module, and I derive some prospects for a time dependent analysis of CRESST-III data, using a statistical frequentist approach based on Monte Carlo simulations. For COSINUS, I provide a significant extension of the pulse shape model currently used by CRESST and COSINUS in order to explain experimental observations related to the COSINUS detector response. Finally, I contribute to ongoing studies on the phonon propagation in NaI crystals based on solid state physics. This PhD thesis has been oriented to fill the gap between theoretical and experimental efforts in the DM field. This approach has facilitated the exchange of expertise, has driven the trend of my research and has stimulated the development of the ideas and methods described in this PhD thesis