This thesis contains an analysis of the activities of logistics research and development corporation Honeywell HTS CZ o. z., on an annual breakdown. It forms the basis for selection of individual consignments of customs regulations and practical application of VAT and other research organizations operating in various sectors. Forms section contains changes to the existing system of customs regulations and logistics department recommendation system settings for different types of organizations that will lead to financial savings.

Short term assignments to other countries are increasing and it is important to take note of the associated potential tax compliance requirements. South Africa is part of the Southern African Development Community (SADC) whose main objective is to advance the development and economic growth of the member countries through regional integration. It is difficult for persons with limited or no international tax background to identify potential taxes when going on short term assignments to other SADC countries as very little has been published with regard to the procedure to follow. The procedure to follow and the main tax concepts (corporate tax, personal tax, VAT and withholding tax) have not been published in a user friendly, holistic format to enable such persons to identify potential tax implications. In this research a conceptual tax-compliance framework was created and tested to enable persons to follow the procedure to identify potential taxes that could be triggered when going on short term assignments. It also enables them to have an understanding of the concepts of the main tax principles applicable in SADC countries that have double tax agreements in place with South Africa. / Dissertation (MCom)--University of Pretoria, 2013. / lmchunu2014 / Taxation / unrestricted

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Магистерская диссертация посвящена исследованию проблем внедрения цифровых технологий в налоговом администрировании России. Выпускная квалификационная работа состоит из введения, трех глав, заключения, списка использованных источников и приложений. В первой главе рассмотрены теоретические аспекты цифровизации процесса налогового контроля. Во второй главе проведен анализ эффективности внедрения цифровизации налогового контроля по налогу на добавленную стоимость в аспекте собираемости этого налога. Третья глава посвящена направлениям совершенствования процессов цифровизации налогового контроля в России. / The master's thesis is devoted to the study of the problems of introducing digital technologies in the tax administration of Russia. The final qualifying work consists of an introduction, three chapters, a conclusion, a list of sources and applications. The first chapter examines the theoretical aspects of digitalization of the tax control process. The second chapter analyzes the effectiveness of the implementation of digitalization of tax control on value added tax in terms of the collection of this tax. The third chapter is devoted to the directions of improving the processes of digitalization of tax control in Russia.

Ultrasound directed self-assembly (DSA) utilizes the acoustic radiation force associated with a standing ultrasound wave field to organize particles dispersed in a fluid medium into specific patterns. The ability to tailor the organization and packing density of spherical particles using ultrasound DSA in a viscous fluid medium is crucial in the context of (additive) manufacturing of engineered materials with tailored properties. However, the fundamental physics of the ultrasound DSA process in a viscous fluid medium, and the relationship between the ultrasound DSA process parameters and the specific patterns of particles that result from it, are not well-understood. Researchers have theoretically described the acoustic radiation force and the acoustic interaction force that act on spherical particles in a standing ultrasound wave field in both inviscid and viscous media. In addition, they have solved the forward and inverse ultrasound DSA problem in an inviscid medium, in which they relate the patterns of particles and the ultrasound DSA operating parameters. However, no theoretical model exists that allows simulating the steady-state and transient local particle packing density in a viscous medium during ultrasound DSA. Thus, in this dissertation, we (i) theoretically derive and experimentally validate a model to determine the steady-state locations where spherical particles assemble during ultrasound DSA as a function of medium viscosity and particle volume fraction. (ii) We also theoretically derive and experimentally validate a model to quantify the steady-state and transient local packing density of spherical particles within the pattern features that result from ultrasound DSA. Using these models, we quantify and predict the locations where spherical particles assemble during ultrasound DSA in a viscous medium, considering the effects of medium viscosity and particle volume fraction. We demonstrate that the deviation between locations where particles assemble in viscous and inviscid media first increases and then decreases with increasing particle volume fraction and medium viscosity, which we explain by means of the sound propagation velocity of the mixture. In addition, we quantify and predict the steady-state and transient local packing density of spherical particles within the pattern features, using ultrasound DSA in combination with vat photopolymerization (VP). We show that the steady-state local particle packing density increases with increasing particle volume fraction and increases with decreasing particle size. We also show that the transient local particle packing density increases with increasing particle volume fraction, decreasing particle size, and decreasing fluid medium viscosity. Increasing particle size and decreasing fluid medium viscosity decreases the time to reach steady-state. Finally, we implement single and multiple scattering in the calculation of the acoustic radiation force for spherical particles in a viscous medium and quantify their relative contributions to the calculation of the acoustic radiation force as a function of ultrasound DSA operating parameters and material properties. We demonstrate that the deviation between considering single and multiple scattering may reach up to 100%, depending on the ultrasound DSA process parameters and material properties. Also, increasing the particle volume fraction increases the need to account for multiple scattering. Quantifying and predicting the local packing density of spherical particles during ultrasound DSA in a viscous medium, as a function of ultrasound DSA process parameters is crucial towards using ultrasound DSA in engineering applications, in particular (additive) manufacturing of engineered polymer matrix composite materials with tailored properties whose properties depend on the spatial organization and packing density of particles in the matrix material. / Doctor of Philosophy / Ultrasound directed self-assembly (DSA) is a technique that uses ultrasound waves to arrange small particles submerged in a fluid into specific patterns. When combined with other manufacturing techniques, ultrasound DSA can be used to fabricate composite materials that derive their properties from the spatial organization of particles in a matrix material. However, ultrasound DSA in viscous fluids is not well-understood. Researchers have studied the forces associated with ultrasound waves that move small spherical particles in an inviscid fluid medium (fluids that experience little to no internal resistance to flow), and they have demonstrated intricate control of the patterns of particles that form using ultrasound DSA. However, that knowledge is not currently available for ultrasound DSA in viscous media. In this dissertation, we develop and evaluate theoretical models to understand ultrasound DSA of small spherical particles in a viscous fluid medium. We simulate where particles organize and how densely they pack together. We also determine the difference of the time-dependent motion of particles in a viscous fluid compared to that in an inviscid fluid medium and relate the difference to the number of particles submerged in the fluid and the viscosity of the fluid. Additionally, we examine the effect of particle size and fluid viscosity on the speed by which the particles reach their final location. We also study how ultrasound waves interact with multiple small particles in a viscous fluid, focusing on the forces that move these particles. We explore two models that account for single and multiple ultrasound wave scattering. Scattering is the process by which ultrasound waves deflect in different directions when they encounter a particle. The results show that the difference between single and multiple scattering models can be significant, depending on the ultrasound DSA process parameters and the properties of the fluid and particles. In general, the importance of accounting for multiple scattering increases with the number of particles submerged in the fluid. Understanding particle packing density when using ultrasound DSA in a viscous fluid is essential in many engineering applications, in particular manufacturing of composite materials that derive their properties from the spatial arrangement of particles in a matrix material.

Multiphase systems provide an opportunity to develop both novel processing methods and create advanced materials through combining the properties of dissimilar phases in a synergistic manner. In this work, we detail the halogenation of poly(ether ether ketone) (PEEK) through both solution-state and gel-state functionalization methods. The multiphase gel-state chemistry restricts functionalization to the amorphous regions of the semi-crystalline parent homopolymer and generates a copolymer with a blocky microstructure. Solution-state functionalization yields random copolymers which provide matched sets to the blocky analogs for fundamental investigations into the effects of polymer microstructure on material properties. Halogenating PEEK using N-halosuccinimides allows for direct installation of pendant halogens along the polymer backbone with facile control of halogen identity. For both bromination and iodination, blocky halogenation of PEEK provides faster crystallization kinetics, higher glass transition (Tg) and melting temperatures as well as superior crystallizability than random halogenation. When comparing halogen identity, increasing halogen size results in increased Tgs, decreased backbone planarity, and for copolymers with blocky microstructures, an earlier onset of phase separation. Increasing halogen size also results in decreased crystallizability and crystallization kinetics, however, these deleterious effects are mitigated in blocky microstructures due to colocalization of the pristine repeat units. Iodination also results in greater flame resistance than bromination for PEEK-based copolymers, and preserved crystallizability allows for the generation of flame retardant aerogels. Direct halogenation of PEEK in the gel-state also provided a reactive microstructural template for subsequent functionalization. Through the use of copper mediated cross-coupling chemistries, the aryl halide functionalities were leveraged to decorate the polymer backbone with pendant perfluoroalkyl chains. The blocky perfluoro alkyl PEEK demonstrated preserved crystallizability and serves as a candidate for compatibilization of poly(tetrafluoroethylene)-PEEK polymer blends. Superacid-modified PEEK was synthesized through a similar methodology and demonstrated over 50,000% increased hygroscopicity relative to the parent homopolymer, and exhibited preserved crystallizability. Multiphase systems were also designed to additively manufacture reinforced elastomers through vat photopolymerization using a degradable scaffold approach that challenged the current paradigm that the scaffold only serves as a geometrical template in vat photopolymerization. The scaffold crosslinks were cleaved through a reactive extraction process that liberated the glassy photopolymer backbone and resulted in over 200% increased ultimate strain and 50% increased ultimate stress relative to a control that was subjected to a neutral extraction. Lastly, thermoresponsive micellar ligands were synthesized as a multiphase approach to environmental remediation of metal-contaminated aqueous systems. / Doctor of Philosophy / Multiphase systems, such as a mixture of oil and water, are of great interest due to their ability to exhibit a multitude of properties from one material. Minimizing the size of the phases, through a technique called compatibilization, often improves the properties of the material. A common example is salad dressing, where the oil phase is compartmentalized into microscopic particles using surface-active molecules known as surfactants. Surfactants, also known as amphiphiles, partition to the interface between different phases due to the surfactants being comprised of dissimilar molecular constituents. One way to generate polymeric amphiphiles, where a polymer is a large molecule comprised of a molecular chain of repeating units, is through synthesizing block copolymers. Block copolymers have blocks of different constituents that are colocalized through covalent bonds in the polymer backbone and often exhibit phase separated structures, allowing for enhanced transport properties such as is seen in membranes. Using semi-crystalline polymers in membranes allows for enhanced mechanical integrity, as the crystallites act as physical crosslinks, or tie points, similar to the knots in a 3D rope ladder. These molecular knots limit the distance that the linear segments of the rope ladder can stretch, which in membranes leads to reduced swelling and increased mechanical performance. In this work we use semi-crystalline polymers to generate blocky copolymers through the use of halogenation. Halogenation installs halogen moieties as pendant groups on the polymer backbone, which can then by used as a chemical handle for subsequent reactions to further incorporate functionality into the copolymer and achieve desired properties such as proton (hydrogen nuclei) transport in fuel cell membranes. Halogenation also allows for the generation of blocky semi-crystalline copolymers for compatibilizing polymer blends of materials like poly(tetrafluoroethylene) and poly(ether ether ketone). Also in this work, we discuss the additive manufacturing of mechanically reinforced elastomers. An elastomer is another type of crosslinked network, and a mechanically reinforced elastomer can be through of as a 3D rope ladder where some of the linear segments of rope are replaced with steel bars, thus increasing the amount of work required to deform the network. The last multiphase systems discussed are similar to salad dressing, where there is a continuous water phase and a microscopic particle phase. The microscopic particles in this work are amphiphilic block copolymers that change their solubility in water with temperature and also have functionalities that should allow for the binding of metals from water-based systems.

Polysiloxanes represent a unique class of synthetic polymers, employing a completely inorganic backbone structure comprised of repeating –(Si–O)n– 'siloxane' main chain linkages. This results in an assortment of diverse properties exclusive to the siloxane bond that clearly distinguish them from the –(C–C)n– backbone of purely organic polymers. Previous work has elucidated a methodology for fabricating flexible and elastic crosslinked poly(dimethyl siloxane) (PDMS) constructs with high Mc through a simultaneous crosslinking and chain-extension methodology. However, these constructs suffer the poor mechanical properties typical of lower molecular weight crosslinked siloxanes (e.g. modulus, tear strength, and strain at break). Filled PDMS networks represent another important class of elastomers in which fillers, namely silica and siloxane-based fillers, impart improved mechanical properties to otherwise weak PDMS networks. This work demonstrates that proper silicon-based reinforcing agent selection (e.g. siloxane-based MQ copolymer nanoparticles) and incorporation provides a synergistic enhancement to mechanical properties, whilst maintaining a low viscosity liquid composition, at high loading content, without the use of co-solvents or heating. Rheological analysis evaluates the viscosity while photorheology and photocalorimetry measurements evaluate rate and extent of curing of the various MQ-loaded formulations, demonstrating theoretical printability up to 40 wt% MQ copolymer nanoparticle incorporation. Dynamic mechanical analysis (DMA) and tensile testing evaluated thermomechanical and mechanical properties of the cured nanocomposites as a function of MQ loading content, demonstrating a 3-fold increase in ultimate stress at 50 wt% MQ copolymer nanoparticle incorporation. VP AM of the 40 wt% MQ-loaded, photo-active PDMS formulation demonstrates facile amenability of photo-active PDMS formulations with high MQ-loading content to 3D printing processes with promising results. PDMS polyureas represent an important class of elastomers with unique properties derived from the synergy between the nonpolar nature, unusual flexibility, and low glass transition temperature (Tg) afforded by the backbone siloxane linkages (-Si-O)n- of PDMS and the exceptional hydrogen bond ordering and strength evoked by the bidentate hydrogen bonding of urea. The work herein presents an improved melt polycondensation synthetic methodology, which strategically harnesses the spontaneous pyrolytic degradation of urea to afford a series of PDMS polyureas via reactions at high temperatures in the presence of telechelic amine-terminated oligomeric poly(dimethyl siloxane) (PDMS1.6k-NH2) and optional 1,3-bis(3-aminopropyl)tetramethyldisiloxane (BATS) chain extender. This melt polycondensation approach uniquely circumvents the accustomed prerequisite of isocyanate monomer, solvent, and metal catalysts to afford isocyanate-free PDMS polyureas using bio-derived urea with the only reaction byproduct being ammonia, a fundamental raw ingredient for agricultural and industrial products. As professed above, reinforcement of polysiloxane materials is ascertained via the incorporation of reinforcing fillers or nanoparticles (typically fumed silica) or blocky or segmented development of polymer chains eliciting microphase separation, in order to cajole the elongation potential of polysiloxanes. Herein, a facile approach is detailed towards the synergistic fortification of PDMS-based materials through a collaborative effort between both primary methods of polysiloxane reinforcement. A novel one-pot methodology towards the facile, in situ incorporation of siloxane-based MQ copolymer nanoparticles into segmented PDMS polyureas to afford MQ-loaded thermoplastic and thermoplastic elastomer PDMS polyureas is detailed. The isocyanate-free melt polycondensation achieves visible melt dispersibility of MQ copolymer nanoparticles (good optical clarity) and affords segmented PDMS polyureas while in the presence of MQ nanoparticles, up to 40 wt% MQ, avoiding post-polymerization solvent based mixing, the only other reported alternative. Incorporation of MQ copolymer nanoparticles into segmented PDMS polyureas provides significant enhancements to modulus and ultimate stress properties: results resemble traditional filler effects and are contrary to previous studies and works discussed in Chapter 2 implementing MQ copolymer nanoparticles into chemically-crosslinked PDMS networks. In situ MQ-loaded, isocyanate-free, segmented PDMS polyureas remain compression moldable, affording transparent, free-standing films. / Master of Science / Polysiloxanes, also referred to as 'silicones' encompass a unique and important class of polymers harboring an inorganic backbone. Polysiloxanes, especially poly(dimethyl siloxane) (PDMS) the flagship polymer of the family, observe widespread utilization throughout industry and academia thanks to a plethora of desirable properties such as their incredible elongation potential, stability to irradiation, and facile chemical tunability. A major complication with the utilization of polysiloxanes for mechanical purposes is their poor resistance to defect propagation and material failure. As a result polysiloxane materials ubiquitously observe reinforcement in some fashion: reinforcement is achieved either through the physical or chemical incorporation of a reinforcing agent, such as fumed silica, or through the implementation of a chemical functionality that facilitates reinforcement via phase separation and strong associative properties, such as hydrogen bonding. This research tackles polysiloxane reinforcement via both of these strategies. Facile chemical modification permits the construction PDMS polymer chains that incorporate hydrogen bonding motifs, which phase separate to afford hydrogen bond-reinforced phases that instill vast improvements to elastic behavior, mechanical and elongation properties, and upper-use temperature. Novel nanocomposite formulation through the incorporation of MQ nanoparticles (which observe widespread usage in cosmetics) facilitate further routes toward improved mechanical and elongation properties. Furthermore, with growing interest in additive manufacturing strategies, which permit the construction of complex geometries via an additive approach (as opposed to conventional manufacturing processes, which require subtractive approaches and are limited in geometric complexity), great interest lies in the capability to additively manufacture polysiloxane-based materials. This work also illustrates the development of an MQ-reinforced polysiloxane system that is amenable to conventional vat photopolymerization additive manufacturing: chemical modification of PDMS polymer chains permits the installation of UV-activatable crosslinking motifs, allowing solid geometries to be constructed from a liquid precursor formulation.

It is a truism that the legal system lags behind societal and technological developments. The common system of VAT is no exception. The objective of this thesis is to examine how the existing VAT rules applies to virtual assets, in particular NFTs and purchasable collectibles in computer games. The aim is to study how transactions with these assets are classified from a VAT perspective and to evaluate whether this classification is compatible with the VAT neutrality principle and the function of VAT as a general tax on final consumption.  One finding related to the classification part of this thesis is that these transactions, which often involve a token and an underlying asset, are treated as a composite supply of services and not a supply of goods for VAT purposes. This implies that the special scheme for second-hand goods cannot be applied. Other classification aspects to assess whether the supply falls within the scope of VAT and whether the supply is taxed or exempt, are also analyzed. There is no ground for NFTs or other virtual assets to be exempt generally. Though, certain types or functions for NFTs may be exempt as financial transactions. The evaluation concludes that the existing rules are partly adapted to handle transactions with these types of virtual assets conducted in a virtual environment. However, the existing rules could lead to an unmotivated double taxation, which may preclude the pursuit of economic activities.

Yes / Three-dimensional printing (3DP) has demonstrated great potential for multi-material fabrication because of its capability for printing bespoke and spatially separated material conformations. Such a concept could revolutionise the pharmaceutical industry, enabling the production of personalised, multi-layered drug products on demand. Here, we developed a novel stereolithographic (SLA) 3D printing method that, for the first time, can be used to fabricate multi-layer constructs (polypills) with variable drug content and/or shape. Using this technique, six drugs, including paracetamol, cffeine, naproxen, chloramphenicol, prednisolone and aspirin, were printed with dfferent geometries and material compositions. Drug distribution was visualised using Raman microscopy, which showed that whilst separate layers were successfully printed, several of the drugs diffused across the layers depending on their amorphous or crystalline phase. The printed constructs demonstrated excellent physical properties and the different material inclusions enabled distinct drug release profiles of the six actives within dissolution tests. For the first time, this paper demonstrates the feasibility of SLA printing as an innovative platform for multi-drug therapy production, facilitating a new era of personalised polypills.