Dip-pen nanolithography (DPN) is a scanning probe microscopy-based nanofabrication method that relies on a fluid-coated atomic force microscope probe for the deposition of material on a substrate with nanometer-scale resolution. The ability to tailor the structure and chemical composition of materials at the nanometer length scale is enabling in elds ranging from medical diagnostics to nano-electronics. While DPN is among the highest resolution additive manufacturing techniques to date, the conguration of ink on the probe and the process of ink transport are poorly understood. Specically, the inking and patterning procedures are susceptible to variations in the ambient environmental conditions and currently not all aspects of the processes are reliably controlled. Thus, a key challenge barring the widespread adoption of DPN beyond a research tool is reproducibility. We hypothesize that closed-loop control over the inking and patterning process could address this irreproducibility, however techniques to monitor the quantity and concentration of ink on the tip of the probe have not been yet developed. Here, we study the mechanics of atomic force microscope (AFM) probes throughout the inking and patterning process to understand if the behavior of the ink can be studied in situ. In particular, we develop an approach for conning ink to the tip of an AFM probe, which is critical for reliable patterning and modeling the mechanics of the probe. Then, we nd that the quantity of ink on an AFM probe can be determined in situ by observing the shift in the natural frequency of the probe. Finally, we show that this method allows for the observation and quantication of the ink deposited on a substrate, in real time. Collectively, these approaches lay the groundwork for a closed-loop implementation of DPN in which the inking and patterning processes are performed with drastically improved reliability. Given that these techniques are easily implemented on any commercial AFM, we expect that they could lead to new applications in the study of nanoscale soft materials. / 2017-11-04T00:00:00Z

Narrow gaps in overlapping structural steel surfaces are problematic when being hot-dip galvanized due to the potential for trapped cleaning solutions between the surfaces. A seal-weld is often used to prevent the cleaning solutions from penetrating this gap. However, these welds are not necessary used for strength, and add fabrication costs because of the additional weld. The purpose of this research is to provide alternatives, which fall under two major categories, to the seal-weld fabrication process. The first one was motivated by the steel fabrication industry and uses a commercial silicone caulk to seal the narrow gap instead of a seal-weld. The second was motivated by the galvanizing industry and increases the narrow gap to a minimum of 3/32 in. to allow free flowing of the liquids including viscous molten zinc. 45 specimens in six different overlapping configurations were tested. Three experimental tasks were performed as part of this research: two different types of silicone caulks were used to partially substitute the seal-weld to prevent fluid penetration; an accelerated corrosion test was performed to determine the long-term corrosion resistance of each configuration; and a coating layer evaluation was performed to investigate the bond of the metallurgical layer between the steel and the coating. Results indicate that silicone only partially prevented the penetration of the cleaning solutions into the gap but performed poorly when fully galvanized. Also, the accelerated corrosion and coating investigations indicated that the suggested caulks and the 3/32 in. gap were not as efficient as the seal-weld solution. / Master of Science / Hot-dip galvanizing is a corrosion protective process for steel. The process involves dipping the base material into a series of different baths. The first set of baths are the cleaning baths and the last bath is the zinc coating bath. In the cleaning baths, certain chemicals are applied to clean the steel surface from oxides and rusts and to prepare the steel for a better zinc coating. When steel members that are fabricated with narrow gaps between overlapping surfaces are subjected to the galvanizing process, the quality of the zinc coating is often inferior along the interface between the two surfaces. This problem occurs because the cleaning solutions—which have a lower viscosity than zinc—get trapped inside the gap while the molten zinc cannot galvanize narrow gaps due to its high viscosity. For this reason, overlapping steel members are seal-welded to prevent such issues. Since seal-welding is not efficient from a fabrication standpoint, the purpose of this research is to provide alternative geometrical overlapping surface configurations. These configurations were subjected to the galvanizing process. To evaluate their performance, three separate tasks were applied through this investigation. The first task involved sealing the gap with commercial silicone sealants instead of a seal-weld, the second task was an accelerated corrosion test, and finally a bond investigation of the coating of the overlapping surfaces was performed. Results have shown that the proposed alternatives did not provide an improved detail for overlapping steel surfaces compared to the existing seal-weld.

It is essential to develop a new type of nanocomposite biomedical implant coatings that consist of bioactive ceramics and polymers, as well as customized surface characteristics. These coatings play a vital role in enhancing cell adhesion, proliferation, and interlocking at the interface between bone tissue and the implant. This development is crucial for prolonging the durability of orthopaedic implants. The utilization of combined colloidal and electrochemical processing techniques, specifically EPD and dip coating, enables the fabrication of these novel multi-component materials with relative simplicity. Additionally, they can be utilized to create nanostructures and surface topography that imitate the composition of human skeletal tissue on a nanoscale level. In addition, colloidal-electrochemical processing techniques can be easily scaled up for clinical product development and mass manufacture, unlike many regularly utilized nanotechnology processing techniques. The absence of efficient and biocompatible dispersants and extractors is a significant obstacle to the widespread use of colloidal-electrochemical methods for fabricating novel biomaterials in EPD, as the success of this process relies on the utilization of a stable colloidal precursor. Biomimetics, sometimes known as gaining inspiration from the natural world, is one way to generating effective dispersion and extracting agents. Using this methodology, we identified novel extracting agents. These agents proved to be highly effective in extracting particles and forming composite films that combined organic and inorganic components, containing different sized of silica particles and polyvinylidene fluoride (PVDF). By extending the method, biomimetic inspiration was derived from the human digestive system, to use bile acid salts (BAS) as solubilizing, charging, dispersing and film-forming agents for the preparation of composite coatings, containing water insoluble drugs and proteins. These coatings have the potential to be utilized for targeted administration of antibiotics, thereby preventing surgical infections after implantation. Furthermore, the inclusion of BAS surfactants enables the solubilization and dispersion of hydrophobic drugs and molecules, as well as the creation of composite films with functional properties using EPD. Moreover, a novel technique is devised for the anodic EPD of alginic acid polymer (AlgH) and composite films that contain drug molecules within the AlgH matrix. This approach entailed utilizing L-arginine as an alkalizing agent to enhance the solubility of medicines that have low solubility in water. AlgH and medication molecules are dissolved in water and then deposited via anodic EPD. Dip coating remains a challenging task when it comes to depositing high concentrations of non-toxic solvents containing high molecular weight (MW) polymers, such as poly(ethyl methacrylate) (PEMA) and poly(methyl methacrylate) (PMMA). In this study, we initially suggested the utilization of water-isopropanol as a co-solvent for dissolving high molecular weight PMMA at high concentrations. Additionally, we utilized an advanced dispersion agent to facilitate the solubilization of PEMA. It was discovered that water molecules can surround and solvate the carbonyl groups of the polymers. This technology avoided the use of noxious solvents and a protracted heating process for their elimination. In addition, these coatings have the potential to be integrated with advanced inorganic particles, such as drugs, diamond and HA, for use in biomedical applications. / Thesis / Doctor of Philosophy (PhD) / There is a need to develop new coatings and manufacturing procedures for biomedical implant materials in order to extend the lifespan of orthopaedic implants used in clinical settings and avoid the need for expensive and unpleasant revision surgeries. Bioactive coatings enhance the durability of orthopaedic implants by reducing scar tissue formation and inflammation, while also increasing the chemical and physical bond between the synthetic implant and natural bone. As bone is a natural composite material, our goal in designing replacement materials is to replicate the inherent chemical composition and structure of human bone. Electrophoretic deposition (EPD) is a manufacturing technology that holds significant potential for creating composite coatings that imitate the structure of natural bone. This approach involves the application of an electric field to deposit charged materials onto a conductive substrate. The primary challenge in the manufacturing process of materials utilizing EPD is the tendency of particles in the precursor suspension to coagulate and distribute unevenly. This ultimately results in unwanted characteristics in the final coatings. An effective method to overcome this problem is by use dispersing agents, which are tiny molecules with either positive or negative charges that disperse particles in a suspension through electrostatic repulsion, physical separation, or a mix of both. Traditional dispersing agents have proven effective in various applications; nevertheless, their toxicity renders them unsuitable for the production of biological materials. This study presents the identification of novel dispersion agents, biomedical coatings, and manufacturing techniques for creating coatings that enhance the durability of implants and possess additional functionalities, such as biosensing for disease detection.

No presente trabalho foram obtidos e caracterizados filmes finos de SnO2 e SnO2:Sb preparados pelo processo sol-gel. Estes filmes foram estudados através da influência do número de camadas nas suas propriedades ótico-eletroquímicas. Foi observado que a densidade de carga para um filme de SnO2:Sb de 5 camadas foi de 40 mC/cm2, tornando-se um excelente candidato como contra-eletrodo para aplicação em janelas eletrocrômicas. Os filmes de SnO2 e SnO2:Sb também foram estudados utilizando técnicas eletroquímicas: cronoamperometria e voltametria cíclica cujo o enfoque na análise foi o de intercalação de lítio em função da carga inserida. As medidas de transmissão ótica na região de ultravioletainfravermelho próximo revelaram que estes filmes possuem leve coloração azul, evidenciadas pela mudança do espectro UV-Vis em 8% entre estado colorido e descolorido; Por espectroscopia no infravermelho dos sóis, foi possível observar bandas características dos grupos de moléculas presentes em alcóxido, confirmando a formação do alcóxido de estanho enquanto dos precipitados apenas evidências da formação do óxido de estanho. As morfologias dos filmes estudadas por Microscopia Eletrônica de Varredura (MEV) e Microscopia de Força Atômica (AFM) demonstraram que o filme apresenta pequenos riscos, provavelmente devido a presença de Sb, e por AFM obtidas informações da rugosidade e do tamanho de grão, sendo estes valores de 100 nm e 104 nm respectivamente. A partir do espectro do filme por EDX foi possível confirmar a presença de estanho e antimônio nos filmes. A estrutura dos xerogéis e dos sóis para deposição dos filmes estudada por difração de raios-X é a casseterite. Por fim Análises Térmicas (DSC/TGA) demonstram que à 60oC um pico endotérmico correspondendo à liberação de água e uma perda da massa de 6,3 %, e na faixa de 450C um pequeno aumento da linha de base no sentido exotérmico atribuído a cristalização do SnO2:Sb na fase casseterite, com perda de massa de 33%. / In this study were obtained and characterized thin films of SnO2 and SnO2: Sb prepared by the sol-gel process. These films were studied through the influence of the number of layers in its optical-electrochemical properties. It was observed that the density of charge for a film of SnO2: Sb, 5 layers was 40 mC/cm2, making it an excellent candidate as counter-electrode for use in electrochromic windows. The films of SnO2 and SnO2: Sb also were studied using electrochemical techniques: chronoamperometry and cyclic voltammetry with a focus on analysis of intercalation of lithium according to load inserted. Measures of optical transmission in the ultraviolet region of near-infrared revealed that these films have light blue colour, highlighted by the changing spectrum of UV-Vis by 8% between state and colorful discolour; In the infrared spectroscopy, in solution has been possible to see bands characteristics groups of molecules present in alkoxide, confirming the formation of alkoxide of tin while the precipitated only evidence of the formation formation of tin oxide. The morphologies of the films studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) showed that the film presents little risk, probably because the presence of Sb, and the information obtained by the AFM roughness and the size of grain, and these values of 100 nm and 104 nm respectively. From the spectrum of the film by EDX were unable to confirm the presence of tin and antimony in the films. The structure of xerogel and solution for deposition of films studied by X-rays diffraction is the cassiterite. Finally Thermal Analysis (DSC / TGA) show that the 60oC a peak endothermical corresponding to the release of water and a loss of the mass of 6.3%, and in the 450ºC a small increase from baseline in the sense attributed range of exothermically the crystallization of SnO2:Sb during casseterite, with mass loss of 33%.

Student Number : 0400486V - MSc (Eng) dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / The Voltage Dip Test Facility at the University of the Witwatersrand utilises a resistive load during testing of variable speed drives. This method produces valuable results regarding the performance of drives under dip conditions. It has been shown that load type does influence the performance of drives and this variation cannot be tested under current conditions as only linear loading is attainable with resistive loads. This thesis proposes a programmable load based on the concept of field-oriented control of an induction motor. The concepts involved with field-oriented control are discussed and shown to be suitable for this application. An implementation strategy utilising custom-designed software and an off-the-shelf VSD is developed and executed. The performance of the programmable load is analysed under both steady-state and dynamic conditions.

The work aimed to identify the needs that still permeated the tools of analysis and detect plagiarism for further development of a new tool, called Miss Marple, which met the requirements identified in the course of research, besides continuing the work called DIP - Evidence of Plagiarism Detector. The research conducted in this work allowed the survey of the characteristics of each tool enabling trace a comparative study between them and the development of the new tool. The validation of the developed tool was performed in two modes of travel, and distance, and by evaluating the usability of the tool. The results showed that Miss Marple tool, developed, presented good results in the analysis of percentage signs of plagiarism coming to an accuracy of approximately 100% and got the best processing time when compared with three of the tools that were studied (Sniffer plagiarism, Plagius detector and VIPER). In addition to the processing time and consistency analysis of evidence of plagiarism, another factor that deserves mention is the construction of the repository file submitted for analysis, which provides the user access to the texts with similar passages that are stored locally on your hardware. / O trabalho desenvolvido objetivou identificar as necessidades que ainda permeavam as ferramentas de análise e detecção de indícios de plágio para posterior desenvolvimento de uma nova ferramenta, denominada Miss Marple, a qual atendesse aos requisitos identificados no decorrer das pesquisas, além de dar continuidade ao trabalho desenvolvido denominado DIP - Detector de Indícios de Plágio. As pesquisas realizadas no decorrer deste estudo possibilitaram o levantamento das características de cada ferramenta estudada, possibilitando tracejar um comparativo entre as mesmas e o desenvolvimento da nova ferramenta. A validação da ferramenta desenvolvida foi realizada em duas modalidades de curso, presencial e a distância, além da avaliação de usabilidade da ferramenta. Os resultados alcançados evidenciaram que a ferramenta Miss Marple, desenvolvida, apresentou bons resultados nas análises de percentual de indícios de plágio chegando a uma precisão aproximada de 100% e obteve o melhor tempo de processamento quando comparada com três das ferramentas que foram estudadas (Farejador de Plágio, Plagius detector e VIPER). Além do tempo de processamento e consistência da análise de indícios de plágio, outro fator que merece destaque é a construção do repositório de análise por arquivo submetido, o qual proporciona ao usuário o acesso aos textos com trechos similares que ficam armazenados localmente em seu hardware.

No presente trabalho foram obtidos e caracterizados filmes finos de SnO2 e SnO2:Sb preparados pelo processo sol-gel. Estes filmes foram estudados através da influência do número de camadas nas suas propriedades ótico-eletroquímicas. Foi observado que a densidade de carga para um filme de SnO2:Sb de 5 camadas foi de 40 mC/cm2, tornando-se um excelente candidato como contra-eletrodo para aplicação em janelas eletrocrômicas. Os filmes de SnO2 e SnO2:Sb também foram estudados utilizando técnicas eletroquímicas: cronoamperometria e voltametria cíclica cujo o enfoque na análise foi o de intercalação de lítio em função da carga inserida. As medidas de transmissão ótica na região de ultravioletainfravermelho próximo revelaram que estes filmes possuem leve coloração azul, evidenciadas pela mudança do espectro UV-Vis em 8% entre estado colorido e descolorido; Por espectroscopia no infravermelho dos sóis, foi possível observar bandas características dos grupos de moléculas presentes em alcóxido, confirmando a formação do alcóxido de estanho enquanto dos precipitados apenas evidências da formação do óxido de estanho. As morfologias dos filmes estudadas por Microscopia Eletrônica de Varredura (MEV) e Microscopia de Força Atômica (AFM) demonstraram que o filme apresenta pequenos riscos, provavelmente devido a presença de Sb, e por AFM obtidas informações da rugosidade e do tamanho de grão, sendo estes valores de 100 nm e 104 nm respectivamente. A partir do espectro do filme por EDX foi possível confirmar a presença de estanho e antimônio nos filmes. A estrutura dos xerogéis e dos sóis para deposição dos filmes estudada por difração de raios-X é a casseterite. Por fim Análises Térmicas (DSC/TGA) demonstram que à 60oC um pico endotérmico correspondendo à liberação de água e uma perda da massa de 6,3 %, e na faixa de 450C um pequeno aumento da linha de base no sentido exotérmico atribuído a cristalização do SnO2:Sb na fase casseterite, com perda de massa de 33%. / In this study were obtained and characterized thin films of SnO2 and SnO2: Sb prepared by the sol-gel process. These films were studied through the influence of the number of layers in its optical-electrochemical properties. It was observed that the density of charge for a film of SnO2: Sb, 5 layers was 40 mC/cm2, making it an excellent candidate as counter-electrode for use in electrochromic windows. The films of SnO2 and SnO2: Sb also were studied using electrochemical techniques: chronoamperometry and cyclic voltammetry with a focus on analysis of intercalation of lithium according to load inserted. Measures of optical transmission in the ultraviolet region of near-infrared revealed that these films have light blue colour, highlighted by the changing spectrum of UV-Vis by 8% between state and colorful discolour; In the infrared spectroscopy, in solution has been possible to see bands characteristics groups of molecules present in alkoxide, confirming the formation of alkoxide of tin while the precipitated only evidence of the formation formation of tin oxide. The morphologies of the films studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) showed that the film presents little risk, probably because the presence of Sb, and the information obtained by the AFM roughness and the size of grain, and these values of 100 nm and 104 nm respectively. From the spectrum of the film by EDX were unable to confirm the presence of tin and antimony in the films. The structure of xerogel and solution for deposition of films studied by X-rays diffraction is the cassiterite. Finally Thermal Analysis (DSC / TGA) show that the 60oC a peak endothermical corresponding to the release of water and a loss of the mass of 6.3%, and in the 450ºC a small increase from baseline in the sense attributed range of exothermically the crystallization of SnO2:Sb during casseterite, with mass loss of 33%.

This thesis focuses on reliability when testing gear efficiency and on how gear mesh efficiency can be increased without detrimental effects on the gears. Test equipment commonly used in gear research was analysed to identify important parameters for gear efficiency testing. The effect of the bearing model's load-dependent losses on gear mesh efficiency was also investigated. Two different surface finishes of gears, ground and superfinished, were investigated to determine how two different load levels during running-in affect gear mesh efficiency and changes in surface roughness. Efficiency and gear temperature were also measured for ground and superfinished gears with dip lubrication, as well as two different forms of spray lubrication (before and after gear mesh contact). Tests on a gear test rig, showed that different assemblies of the same test setup can yield different measurements of torque loss. The applied bearing model had a significant effect on the estimated gear mesh efficiency. The mesh efficiency of ground gears is affected by the running-in procedure, with a higher running-in load resulting in a higher mesh efficiency than a lower load. This effect was not seen for superfinished gears, which show the same gear mesh efficiency for both running-in loads. Gearbox efficiency increased with spray lubrication rather than dip lubrication. The gear mesh efficiency increased, and thus gear temperatures were reduced, when superfinished gears were used rather than ground gears. A lower gear temperature was measured when gears were spray lubricated at the mesh inlet rather than the mesh outlet. / <p>QC 20170314</p>

Y company started in 1988 positioned to be the largest and the most advanced coated steel producer. Y company (includes the plant in China)Owned seven continuous hot-dup galvanizing lines , five continuous pre-painting lines¡A6 cold rolling mills and 2 pickling lines .Y company has become not only the biggest coated steel producer in Taiwan ,Mainland China and South East Asia , but also one of the 15th largest producers of coated steel products in the world. Y company is able to offer a wide range of finished products to meet the needs of our customers one-stop shopping need. Y company is a coated ¡V steel producer which produce hot¡Vdip galvanized coils and pre-painted coils by means of the manufacturing process of pickling ,cold rolling ,hot-dip galvanizing and pre-painting .On recent ten years ,the steel market changes sharply, but Y company keep growing continuously , the key factor is to establish the strategic alliance with F company to replace electroplating steel sheet with hot-dip galvanized in computer cases . This research is studying the experience story, which we have overcame a number of difficulties during the period developed the ¡§replacing electroplating steel sheet with hot-dip galvanized in computer cases ¡¨and ¡§developing environmentally- friendly steel ¡¨. it is a story that the strategic alliance strenghthen organization ¡Fand after organization empowerment ¡Ait made the relationship between the members of the strategic alliance more closely. This story is to show the difficulties and challenges what we face by means of the Narrative Inquiry and hope to achieve the next success for the next opportunity on the basis of meanings from this story .

A method offering precise control over the synthesis conditions to obtain carbon nanotube (CNT) samples of a single chirality (metallic or semi-conducting) is presented. Using this nanolithographic method of catalyst deposition, the location of CNT growth is also precisely defined. This technique obviates three significant hurdles that are preventing the exploitation of CNT in micro- and nano-devices. Microelectronic applications (e.g., interconnects, CNT gates, etc.) require precisely defined locations and spatial density, as well as precisely defined chirality for the synthesized CNT. Conventional CVD synthesis techniques typically yield a mixture of CNT (semi-conducting and metallic types) that grow at random locations on a substrate in high number density, which leads to extreme difficulty in application integration. Dip Pen Nanolithography (DPN) techniques were used to deposit the catalysts at precisely defined locations on a substrate and to precisely control the catalyst composition as well as the size of the patterned catalyst. After deposition of catalysts, a low temperature Chemical Vapor Deposition (CVD) process at atmospheric pressure was used to synthesize CNT. Various types of catalysts (Ni, Co, Fe, Pd, Pt, and Rh) were deposited in the form of metal salt solutions or nano-particle solutions. Various characterization studies before and after CVD synthesis of CNT at the location of the deposited catalysts showed that the CNT were of a single chirality (metallic or semiconducting) as well as a single diameter (with a very narrow range of variability). Additionally, X-ray photoelectron spectroscopy (XPS) was used to characterize the deposited samples before and after the CVD, as was lateral force microscopy (LFM) for determination of the successful deposition of the catalyst material immediately after DPN as well as following the CVD synthesis of the samples. The diameter of the CNT determines the chirality. The diameter of the CNT measured by TEM was found to be consistent with the chirality measurements obtained from Raman Spectroscopy for the different samples. Hence, the results showed that CNT samples of a single chirality can be obtained by this technique. The results show that the chirality of the synthesized CNT can be controlled by changing the synthesis conditions (e.g., size of the catalyst patterns, composition of the catalysts, temperature of CVD, gas flow rates, etc.).