Miracle-dz/UniFAR-FTUs huggingface dataset:
Synthesis and characterization of infrared quantum dots

This thesis focuses on the development of synthetic methods to create applicationready quantum dots (QDs) in the infrared for biological imaging and optoelectronic devices. I concentrated primarily on controlling the size and size distribution of indium arsenide and cadmium arsenide QDs. In the nanocrystal community, classical nucleation and growth is often invoked to explain size focusing. However, this model lacks predictive power and contradicts what is known about the chemistry of QD growth. I try to relate my experimental approach and my conclusions to our understanding of the mechanism of particle growth. This approach led me to explore the role of precursor conversion rate in the growth of III-V QDs and to develop a continuous injection synthesis method that I used to make both III-V and cadmium arsenide QDs. Cadmium arsenide (Cd 3As 2 ) is a narrow gap semiconductor that can form QDs with tunable emission between 530nm and 2000nm. I developed a synthetic strategy to precisely control the size of Cd3As 2 QDs while maintaining a narrow size distribution. Continuous precursor injection was used to drive growth and suppress size broadening. The quantum yields of Cd 3As 2 QDs produced using this method ranged as high as 80%, and their emission is tunable over a broad range with narrow linewidths. However, they were found to be unstable in ambient conditions. Nevertheless, by processing in inert conditions we were able to make a crude photodetector that demonstrates that Cd3As 2 QDs are sufficiently stable for use in optoelectronic devices. Although growth of a Cd3 P2 shell provided enough added stability to observe emission after ligand exchange into water, these core-shell structures do not seem to be robust enough for biological applications. Indium arsenide (InAs) QDs are more easily stabilized with a core-shell structure. However, the spectral linewidths are broad and existing synthetic techniques produce only small particles with limited spectral tunability. Models predicted that decreasing precursor reactivity would produce larger, more monodisperse particles. Therefore, I chemically modified the group-V precursor to reduce reactivity. I made a library of group-V precursors, and I developed a framework for comparing the QDs that they produced and measuring the kinetics of precursor conversion and particle growth.
Tapered hollow waveguide multiplexer for multi-wavelength VCSEL array

A tapered hollow waveguide multiplexer is proposed to combine the output of a multi-wavelength VCSEL array. The design of the proposed hollow waveguide is presented based on ray optics. We demonstrated the multiplexing of 4- channel output of a VCSEL array for coupling into a multi-mode fiber with the tapered hollow waveguide. The wavelength of each channel was allocated with adjusting driving current. The proposed hollow waveguide multiplexer is useful for realizing compact and low-cost WDM transceivers with a multi-wavelength VCSEL array for high capacity short reach optical networks.
Estimation of parameters of gas diffusion in models of microtransfactions of different type by the method of molecular dynamics

Estimation of gas transport parameters in organic nano-porous materials, such as kerogens, is important for understanding the fundamentals of the processes that co-produce natural gas. In this regard, the description and numerical parameterization of the processes of transfer of components of natural gas occurring at the micro level in organic nano-porous materials is of interest both from fundamental and practical points of view, including the search for possible ways to optimize the yield of natural gas and boost recoil. The purpose of this study is to study the methods of molecular modeling and the molecular dynamics of the mechanisms of gas transport in structures that mimic organic nano-porous materials, and the numerical evaluation of mass transfer parameters.
Materials selection for life cycle design

The use of recycled materials is increasingly important worldwide as product take-back and producer responsibility legislation are mandated, product labeling programs are adopted, and sustainability goals are promoted. In this paper, we review materials selection guidelines and provide over one hundred references. We distinguish between component level and product level materials selection guidelines. We discuss the relationship between the life cycle timeline and the impact of the materials selection guidelines. We illustrate how materials selection decisions impact distribution, consumer use, repair and refurbishment, and other end-of-life activities. Finally, we survey both qualitative and quantitative materials selection methods. We summarize the development of models to assist designers with (i) insights into end-of-life product management strategy, (ii) use of recycled materials, and (iii) design selection with integrated consideration of materials, manufacturing, and end-of-life impacts.
Nearly real-time monitoring of gearbox vibration signal using DWT

Gearbox diagnosis is challenging in engineering because the vibration signals from a gearbox are complex. The spectral analysis carried out for monitoring the mechanical transmission has a substantial limitation for realizing a real-time monitoring process. To overcome this shortcoming, it was decided to introduce a nearly real-time technique that, while maintaining a high specificity, is able to provide greater sensitivity for detecting significative variations of vibration signal. That kind of approach, as will be discussed in this paper, should earlier detect dynamical irregularity inside the gearbox. The aim is to perform a nearly real-time monitoring in order to stop the duration test faster than the methods reported in our previous papers.
Enhanced phase retrieval for non-ideal in-line phase contrast x-ray imaging based on deep learning

In-line X-ray phase contrast imaging (IL-PCI) is a promising technology for clinical diagnosis because of its great advantage in distinguishing low contrast tissues and simple structure to implement. In order to recover the phase projections from the phase contrast measurements, conventional phase retrieval methods were developed based on assumptions such as homogeneous material, weak attenuation, and thus suffered from limited generalizability, practicability and feasibility. Deep learning-based methods have been proposed for phase retrieval and great success has been achieved. While the practical physical model of phase contrast imaging hasn’t been fully considered including the non-ideal effects of finite size of the x-ray micro focal spot, finite pixel size of the detector and the system noise. In this paper, a convolutional network based on generative adversarial network is proposed to retrieve the phase projections with fully considering the non-ideal effects in IL-PCI. The network composed of a generating network from which the phase projections were retrieved and a discriminating network from which the difference between the output of generation network and the reference phase projection is processed and backpropagated to the input of the network. Phase contrast measurements of the microspheres phantom were simulated and retrieved by the conventional methods and the proposed network. Results show the superiority of the proposed network in spatial resolution and noise suppression compared with the conventional method.
An analysis of recruitment sources and employee turnover in Scottish construction organizations

The aim of this research is to test the hypothesis that particular recruitment sources are associated with employee turnover within certain construction organizations. Hypothesis validity would enable management of similar organizations, through the use of more favourable recruitment sources, to reduce or eliminate the employment of individuals who may yield shortened periods of tenure. In the research, 15 recruitment sources used by construction organizations to obtain new employees are compared in terms of their influence on employee tenure and turnover. Personnel records of construction organizations were analysed and from this analysis sources identified which are associated with lower turnover rates and also of stable or longer employee tenure. For each of the organizations considered, specific sources are shown to be indicators of stable employee tenure. Conversely, each organization demonstrates sources which are shown to be associated with high levels of employee turnover.
Eco-comparison between ceramic and epoxy based populated PWBs

Goal of the study is the ecological comparison between ceramic and epoxy based populated printed wiring boards (PWB) by using generic modeled LCA. All relevant differences of the product systems, their manufacturing as well as effects in and from the following life cycle stages are taken into consideration. The methodology of "generic modules based LCA" is used to realize the modeling of two product systems that are marked by so many and different characteristics and application fields. This approach consists of forming flexible modules allowing parameter variation that contain pre-modeled parts and subassemblies. It was already presented formerly and its applicability is proven. Both products focusing on the populated PWBs are modular structured. The LCA modules reflect this structure and allow the calculation of eco-profiles. Also, specific technical issues have to be regarded that a meaningful comparison can take place. For instance the ceramic based hybrid PWB uses pastes with electrical functions like resistors. The paper demonstrates the ecological profiles of both product systems assuming the same functionality and taking into consideration significant technical issues. The comparison shows which modules are affected and how they have been adapted to provide a comparable functional unit. It results in a comprehensive appraisal and evaluation of ecological benefits and burdens. All significant effects-product internal and of their periphery-caused by the differences of epoxy based and ceramic based populated printed wiring boards are discussed, evaluated and interpreted.
Silicon lens-coupled bow-tie InGaAs-based broadband terahertz sensor operating at room temperature

A passive detection scheme for broadband, 10 GHz-2.52 THz, sensing at room temperature is demonstrated using a hemispherical silicon lens-coupled diode of an asymmetrically-shaped bow-tie geometrical form. The device is fabricated from an MBE-grown In/sub 0.54/Ga/sub 0.46/As wafer as mesas of 3 /spl mu/m depth produced by wet etching. The detector exhibits voltage sensitivity about 5 V/W below 1 THz.
Use of Reduction-Effectiveness Ratios to Evaluate Reduced Traffic Data Collection Plans

Because of budget shortfalls in recent years, state departments of transportation (DOTs) must adjust their traffic data collection plans by reducing data collection locations or extending data collection cycles; however, few studies have been performed to evaluate the cost-effectiveness of various efforts to reduce data collection. This study developed a quantitative method for evaluating the impact of various reduced plans for traffic data collection on the overall accuracy of the annual average daily traffic (AADT) estimation. The mean absolute percentage error is calculated to compare the accuracy of 10 reduced data collection plans with a base plan. In addition, a reduction-effectiveness ratio (i.e., the percentage of reduced data collection cost to the percentage of increased AADT estimation error) is proposed. Results from this study show that the current practice, which randomly selects data collection sites on the basis of different cycles, performs well in maintaining AADT estimation accuracy but may not be the most cost-effective approach. Results also show that certain types of sites, such as rural sites, lower-AADT sites, and sites with higher AADT variation, tend to produce larger errors if they are not counted. The results imply that the proposed method both provides a quantitative means with which to evaluate plans for reduced data collection and suggests ways to enhance current data collection and traffic estimation practices. The method also enriches the information provided to state departments of transportation for effective and informed decision making with limited resources.
Projeto TEC-LEC: Modelo de nova metodologia em EAD incorporando os recursos da telemática

This article presents a distance learning course creating a learning community's model. Published materials and net services that compose the course are avaible in two servers - penta.ufrgs.br and psico.lec. ufrgs.br. The objective in to ofter virtual constructivist learning environments dor inservice teachers. Initially, all particpants are teachers working on the project EducaDi/CNPq/1997. In time, participation will be opened tio all interested teachers. The course is organized in five independent modules, with no particular sequence to be followed. Other modules are expected to be proposed and put online by students joining the course. Forms ans CGIs organize the virtual spaces to support and stimulate interation between the lerning community. The portfolios assessment accommodate individual and group studies and project development reports. They constitute the major constructionist resources in the course. Reports will be analyzed, discussed and criticized in co-operative ways within the learning community. The course's menu presents registration form, portifolio assessment,discussion forum (IRC, videoconference), library, guest book and events database.
A programmable filter with self-tuning for DMT VDSL receiver

This paper presents a programmable filter with a self-tuning mechanism. Conformed with the DMT-VDSL (discrete multi-tone very-high-speed digital subscriber loop) system, the filter is configured as a 4-th order Chebyshev low-pass filter with programmable bandwidth in which the ripple is set to 0.5 dB. The cut-off frequencies are 1.104/spl times/2/sup n/ MHz, where n is 0, 1, 2, 3, 4, corresponding to different transmission rates. The filter is self-tuned by the proposed tuning mechanism that is based on the relation between DC and fundamental components of a filtered clock signal. Peak-and-valley detection is employed to observe the two frequency components in the time domain. Implemented in 0.35 /spl mu/m 1P4M digital CMOS technology, the circuit occupies an active area of 1.3/spl times/1.4 mm/sup 2/. According to the post-layout simulation, it achieves 55 dB THD using 2 V supply voltage while the output swing is 120 mV/sub pp/. The power consumption for the core filter is 2.8 mW, whereas the overall system, including the filter, the output buffer, and the tuning circuits, consumes 28 mW power.
Optimization-based non-linear yaw moment control law for stabilizing vehicle lateral dynamics

Abstract For a direct yaw moment control (DYC) system, using an external yaw moment that is as low as possible for stabilizing the vehicle-handling dynamics in the non-linear regimes can be considered as an important advantage. In this paper, to achieve this aim, an optimization-based side-slip tracking law is developed for DYC by the response prediction of a continuous non-linear vehicle dynamics model. A new desired model for the vehicle side-slip angle based on the linear vehicle model and tyre-road conditions is presented to be tracked by the controller. Two versions of the proposed non-linear control law are considered here and the performances of the two versions are compared. The derived control law has an analytical closed form in which online numerical computations in optimization are not required. The effectiveness of the designed controller is investigated by simulations of various manoeuvres using a developed, non-linear, full-vehicle dynamic model. The simulation results indicate that a satisfactory handling performance through a reduced external yaw moment can be achieved when the proposed optimal controller is applied.
Software-based simulation for preprocedural assessment of Tubridge flow diverter sizing: a validation study

Background: The purpose of this single-center retrospective review was to validate the use of a software-based simulation of Tubridge flow diverter (FD) in the treatment of intracranial aneurysms. In a single-center cohort of 17 patients undergoing aneurysm treatment with the Tubridge flow divert, we analyzed their pre- and post-procedural angiographic studies to compare the manufacturer-given nominal length (NL), software calculated simulated length (SL), and the actual measured length (ML) of the flow divert using software. Results: Data for the 3 lengths of all 17 patients treated with Tubridge flow diverts were collected and analyzed in this study. Error discrepancy was calculated by mean squared error (ML to NL 10.64; SL to NL 9.95 p>0.05), mean absolute error (ML to NL 2.64; SL to NL 2.60 p>0.05), and mean error (NL to ML 1.26; SL to ML 2.59 p>0.05). Conclusions: The SL was usually greater than the NL given by the manufacturer, indicating significant change in length in most cases. The residual comparing the ML to the NL was significant, as was when comparing the SL to the NL. The assessment of the Tubridge flow diverter using software simulation is safe and effective and the accurate calculating of FD length contributed to the right-sized FD for optimal placement in intracranial vasculature.
Design Construction of Beam Structured Vertical Drive SMA Thin Film Actuator for Small Tactile Display

Wataru Yoshikawa Non-member (Kyoto University, wataru@nms.me.kyoto-u.ac.jp) Akio Sasabe Non-member (ROHM.CO.LTD, Akio.Sasabe@dsn.rohm.co.jp) Kouji Sugano Member (Kyoto University, sugano@me.kyoto-u.ac.jp) Toshiyuki Tsuchiya Member (Kyoto University, tutti@me.kyoto-u.ac.jp) Akira Ishida Non-member (National Institute for Material Science, ISHIDA.Akira@nims.go.jp) Osamu Tabata Senior Member (Kyoto University, tabata@me.kyoto-u.ac.jp)
Anticipatory cash transfers in climate disaster response

This document supplements the original pre-analysis plan (available at https://www.socialscienceregistry.org/trials/6576 ) last updated November 30, 2020. It follows preparatory analysis of anonymised data. Blind to the outcomes, we revise the construction of treatment and control groups. Blind to treatment status, we update the measurement of some outcomes.
Fluctuations in space-charge-limited currents

The paper shows that the fluctuations in the anode current of a space-charge-limited valve can be calculated in a manner exactly similar to the calculation of the thermal agitation noise in a metallic conductor, in terms of the electron transits. Corresponding values of the noise ratio, or ? smoothing factor,? are derived; they are found to be in agreement with experimental data from a variety of sources. The ratio is a function of eV/(k? ), and is only slightly dependent upon the ratio of anode diameter to cathode diameter of the valve.
Horn Antennas and Dual-Polarized Circuits in Substrate Integrated Waveguide (SIW) Technology

The Substrate Integrated Waveguide (SIW) technology is a very promising candidate to provide widespread commercial solutions for modern communications systems. Its main advantage is the possibility to integrate passive/active components and antennas in the same substrate by using standard manufacturing processes, such as the Printed Circuits Board (PCB) processing technique. Nevertheless, the production of low-cost SIW devices is inherently linked to commercially available substrates and fabrication methods. In particular, these constraints usually limit (a) the frequency range of operation of certain SIW antennas and (b) the possibility of creating multimode structures dealing with orthogonal polarizations. The motivation of this PhD thesis is to overcome these two limitations by proposing innovative SIW components based on PCBs in order to favour the compatibility with existing systems and to lower their cost. Hence, the usage of the SIW technology would be extended towards new applications and scenarios. One type of antenna strongly affected by the limitation (a) is the H-plane SIW horn antenna. While standard horns are employed in many applications and in a wide range of frequencies, their counterparts in SIW technology are restricted to the Ka-band and above. At lower frequencies, commercial substrates are electrically thin and the performances of these end-fire antennas severely diminish. To solve this problem, a novel low-profile SIW horn antenna has been designed to be used at the Ku-band and below, while offering wideband characteristics. In addition, the horn shape has been further optimized to reduce the antenna footprint for a given directivity. In order to overcome the limitation (b), a substrate integrated guide able to simultaneously carry orthogonally polarized modes has been developed: the so called Extended Substrate Integrated Waveguide (ESIW). An ESIW dual-polarized system composed of an Orthomode Transducer (OMT) feeding a dual-polarized horn antenna has been designed and experimentally verified. The overall combination of concepts and ideas proposed in this thesis opens the door towards new SIW components that can increase the capacity, robustness and compactness ofmodern communication systems.
The Role of Dense Gas Dynamics on Organic Rankine Cycle Turbine Performance

In this paper we investigate the real gas flows which occur within Organic Rankine Cycle (ORC) turbines. A new method for the design of nozzles operating with dense gases is discussed, and applied to the case of a high pressure ratio turbine vane. A Navier-Stokes method which uses equations of states for a variety of working fluids typical of ORC turbines is then applied to the turbine vanes to determine the vane performance. The results suggest that the choice of working fluid has a significant influence on the turbine efficiency.
Enhancement of a unimorph actuator performance implementing the nonlinear characteristics of piezoceramic wafer (3203HD, CTS)

In this study, the actuation displacement and blocking force of the LIPCA (Lightweight Piezo-Composite Actuator) under various combination of the external compressive load and prescribed voltage have been numerically and experimentally examined. For numerical analysis, the full three-dimensional model of the LIPCA including two end-tabs in the simply supported configuration was used and the measured nonlinear behavior of the bare piezoceramic wafer (3203HD, CTS) was implemented in the geometrically nonlinear finite element analysis. The central out-of-plane displacement of the LIPCA was measured while applying various electric fields and compressive loads at the same time. Dummy weights were added at the center of the LIPCA until the LIPCA cannot produce additional central actuation displacement for a given excitation voltage and the sum of the dummy weight was regarded as the blocking force. The numerical results acquired by geometrical/material nonlinear finite element analysis and the measured data showed a good agreement even for high electric field and compressive load. The investigation showed that the actuation displacement and blocking force of the LIPCA were significantly increased by pre-applied compressive load. At the same electric field, the actuation displacements of the LIPCA under nearly buckling load could be about two times larger than those without compressive load. The results also indicate that the positive voltage should be better applied to the actuator than the negative voltage. Therefore, the high negative electric field, which causes the polarization switching in the piezoceramic wafer, can be avoided in applications. At +150V, the blocking force of the compressed actuator under near buckling load was also increased around 26% higher than that of the actuator without compressive load.