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HALMBALSHUS – EN STUDIE MED FOKUS PÅ FUKTPROBLEM : Begränsning av fuktlasten med hjälp av fallstudier utförda i Wufi / STRAW BALE HOUSES - A STUDY WITH FOKUS ON MOISTURE PROBLEMRashed, Assad January 2021 (has links)
The purpose of this work has been to create substrates that can contribute to more moisture-proof straw bale constructions through simulations in Wufi Pro. The aim was to simulate different cases with incremental variations of different parameters and to investigate the moisture significance of the parameters. This in order to later, with the help of the results, draw conclusions about how a moisture-proof construction of straw bales can be achieved. The method of carrying out the work was to utilize; previous studies and literature on the subject, Wufi Pro 6 and Wufi Bio 3.5. The results showed that: · The moisture content of the straw layer varies, among other things, depending on the facade orientation and geographical location. For Karlstad facades to the south-east and south are most exposed to moisture when rain cover (coat or hat) is lacking. · Most exposed to moisture is the straw layers near the cold side of the outer wall. · Increasing the interior clay thickness slightly reduces the moisture content of the straw layer. · Increasing the outside clay plaster thickness slightly increases the moisture content of the straw layer to a certain thickness and then decreases the same. · Addition of outer panel and air gap reduces RH (relative humidity) in the straw layer by about 9%. · Constrution in the spring is preferable given the risk of microbial growth (for Karlstad). · Surface treatments prolong the drying time but reduce moisture in the straw layer afterwards. · Straw structures are exposed to less risk of microbial growth in warmer climates. The conclusions can be summarized as follow: · Moisture design should take into account differences in moisture load depending on facade orientations. · It is very important to protect the facade from direct rainfall. · It is desirable to have thicker plaster on the warm side of the outer wall campared to the cold side plaster (about twice as thick as the cold side plaster thickness). · Work steps that add moisture to the straw layer, such as plastering, should take place during the spring. · The building moisture must be minimized. · Increasing the diffusion density of the wall surfaces increases the drying time, which entails moisture risk in the event of moisture leaks to the straw layer. · Straw can be used as insulation in conventional buildings with moisture brakes, provided that moisture leaks caused by unforeseen damage do not occur. · If surface treatments are to be used, this should be done after the building moisture has dried out.
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Vstupní díl UHF přijímače s velmi nízkou spotřebou / Tuner for UHF Receiver with Low Power ConsuptionKaštánek, Martin January 2008 (has links)
The purpose of this work was to make a proposal for input parts of receiver for band 430 to 440 MHz. A model of chosen semiconductor triode BFP540 was created in simulation software. Possibilities how to decrease consumption of this semiconductor triode, keeping the profit, were investigated through the simulation.In compromise consumption, keeping the profit of the amplifier - an optimal operating point for this semiconductor triode UCE = 1,2 V and IC = 2 mA was found. It was tested through the testing wiring with noise microstrips conformity. Ascertained knowledge was used for construction of tuner for UHF receiver. An operating point of input amplifier of UHF receiver was owing to power supply amplifier forced for bigger effectiveness to UCE = 2,65 V and IC = 2,0 mA. Suppression of mirror frequency is provided with Helix filter of the third order, because of intermediate frequency 10,7 MHz. Mixing on intermediate frequency is made again by semiconductor triode BFP540. Selectivity of receiver is provided with intermediate frequency crystal filter 10,7 MHz with bandwidth 15 kHz. Designed input part enables reception of SSB, FM and digital types of modulation.Bandwidth intermediate frequency exit is adapted to this request To receive particular modulation , it is necessary to complete intermediate frequency signal way with appropriate intermediate frequency filter.
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Výkonový zesilovač pro pásmo krátkých vln / Shortwave power amplifierZamazal, Bořivoj January 2015 (has links)
This semestral thesis describes RF power amplifier design. In the first section of the work, the possible solutionsand a reflection on the possible solution are presented. In the second section, the principle and thesis for power amplifier design is described. In the third section, the power amplifier design, based on the theoretical knowledge, is described.
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Výkonový zesilovač pro pásmo krátkých vln / Shortwave power amplifierZamazal, Bořivoj January 2015 (has links)
This master‘s thesis describes RF power amplifier design. In the first section of the work, the possible solutions and a reflection on the possible solution are presented. In the second section, the principle and thesi for power amplifier design is described. In the third section, the power amplifier design, based on the theoretical knowledge, is described and in fourth section the finaly construction solution and real parameters are described. The last part sumarized the results of this thesis.
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Simultaneous Positioning and Communications: Hybrid Radio Architecture, Estimation Techniques, and Experimental ValidationJanuary 2019 (has links)
abstract: Limited spectral access motivates technologies that adapt to diminishing resources and increasingly cluttered environments. A joint positioning-communications system is designed and implemented on \acf{COTS} hardware. This system enables simultaneous positioning of, and communications between, nodes in a distributed network of base-stations and unmanned aerial systems (UASs). This technology offers extreme ranging precision ($<$ 5 cm) with minimal bandwidth (10 MHz), a secure communications link to protect against cyberattacks, a small form factor that enables integration into numerous platforms, and minimal resource consumption which supports high-density networks. The positioning and communications tasks are performed simultaneously with a single, co-use waveform, which efficiently utilizes limited resources and supports higher user densities. The positioning task uses a cooperative, point-to-point synchronization protocol to estimate the relative position and orientation of all users within the network. The communications task distributes positioning information between users and secures the positioning task against cyberattacks. This high-performance system is enabled by advanced time-of-arrival estimation techniques and a modern phase-accurate distributed coherence synchronization algorithm. This technology may be installed in ground-stations, ground vehicles, unmanned aerial systems, and airborne vehicles, enabling a highly-mobile, re-configurable network with numerous applications. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2019
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ELECTROMAGNETIC SIMULATION OF PARALLEL TRANSMIT RADIOFREQUENCY COILS AND HIGH PERMITTIVITY MATERIALS USING CIRCUIT-SPATIAL OPTIMIZATION WITH VIRTUAL OBSERVATION POINTSXin Li (9193727) 04 August 2020 (has links)
<p>The recent FDA regulatory clearance
for the 7 tesla Magnetic Resonance Imaging (MRI) system has led to increased
interest in clinical ultra-high field (UHF) applications. However, to robustly
achieve the expected increase in signal-to-noise ratio (SNR) at UHF, the
radiofrequency (RF) challenges need to be met, namely, problems with higher RF
power, worse <i>B<sub>1</sub><sup>+</sup></i> inhomogeneity (signal voids) and increased
tissue dielectric properties at higher frequency, all of which usually results
in increased specific absorption rate (SAR). The parallel transmission (pTx)
techniques are generally accepted as a realistic solution, providing
improvement in the <i>B<sub>1</sub><sup>+</sup></i> homogeneity with good RF efficiency while
reducing peak local SAR. We designed a hybrid circuit-spatial
domain optimization to accelerate the design of a double row pTx head coil.
The method predicted consistent coil scattering parameters, component values
and <i>B<sub>1</sub><sup>+</sup></i> field. RF shimming of the calculated field
maps matched in vivo performance. To further
increase the <i>B<sub>1</sub><sup>+</sup></i> homogeneity in tissue, we added high dielectric material (HPM) pads
near the coil, as the displacement currents in the HPM induced secondary <i>B<sub>1</sub><sup>+</sup></i> in tissue. This raises a RF safety question
of how to monitor millions of local SAR (complex valued Q-matrix) in the tissue
voxels, for any weightings (forward voltages) applied to the pTx system. We implemented
VOPs based on singular value decomposition to compress the Q-matrices with a
compression ratio >100, effectively monitoring the maximum peak local SAR
values at given weighting amplitudes.</p>
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Additively Manufactured Vanadium Dioxide (VO2) based Radio Frequency Switches and Reconfigurable ComponentsYang, Shuai 08 1900 (has links)
In a wireless system, the frequency-reconfigurable RF components are highly desired because one such component can replace multiple RF components to reduce the size, cost, and weight. Typically, the reconfigurable RF components are realized using capacitive varactors, PIN diodes, or MEMS switches. Most of these RF switches are expensive, rigid, and need tedious soldering steps, which are not suitable for futuristic flexible and wearable applications. Therefore, there is a need to have a solution for low cost, flexible, and easy to integrate RF switches.
All the above-mentioned issues can be alleviated if these switches can be simply printed at the place of interest. In this work, we have demonstrated vanadium dioxide (VO2) based RF switches that have been realized through additive manufacturing technologies (inkjet printing and screen printing), which dramatically brings the cost down to a few cents. Also, no soldering or additional attachment step is required as the switch can be simply printed on the RF component. The printed VO2 switches are configured in two types (shunt configuration and series configuration) where both types have been characterized with two activation mechanisms (thermal activation and electrical activation) up to 40 GHz. The measured insertion loss of 1-3 dB, isolation of 20-30 dB, and
switching speed of 400 ns are comparable to other non-printed and expensive RF switches.
As an application for the printed VO2 switches, a fully printed frequency reconfigurable filter has also been designed in this work. An open-ended dual-mode resonator with meandered loadings has been co-designed with the VO2 switches, resulting in a compact filter with decent insertion loss of 2.6 dB at both switchable frequency bands (4 GHz and 3.75 GHz). Moreover, the filter is flexible and highly immune to the bending effect, which is essential for wearable applications.
Finally, a multi-parameter (switch thickness, width, length, temperature) model has been established using a customized artificial neural network (ANN) to achieve a faster simulation speed. The optimized model’s average error and correlation coefficient are only 0.0003 and 0.9905, respectively, which both indicate the model’s high accuracy.
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Applications and Limitations of the Hybrid L1/L2Multicarrier Analysis MethodJanzon, Alexandra January 2021 (has links)
The multipactor phenomenon is a major concern in modern satellites that operate with highpower transmission in many frequency bands. It occurs when electrons inside RF componentsare accelerated by the RF fields. These electrons then hit walls inside the device, produc-ing secondary electrons. As the number of electrons increases, it may create noise inside thecomponent, thus deteriorating the original signal-to-noise ratio. When designing radio fre-quency equipment for space applications, it is therefore important to know at which powerlevels this occurs. Multicarrier simulations are time consuming and demand high amounts ofcomputer resources. In this thesis the hybrid L1/L2 method has been tested, which is a methodthat separates the geometric and multicarrier simulations into two parts resulting in a shortercomputation time. The conclusion is that the method is more reliable than single carrier sim-ulations, and that it can be used as a first step in the designing process of RF components.It is also a way of estimating a preliminary threshold before starting a full-scale multicarriersimulation.
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External Validation of the MMPI-A-RF with Youth with Mental Health Needs: A Systematic Examination of Symptom-Based Correlates and Interpretive StatementsSharf, Allyson J. 08 1900 (has links)
Over the last several decades, the Minnesota Multiphasic Personality Inventory - Adolescent (MMPI-A) has remained one of the most extensively studied and commonly used adolescent assessment measures. Most recently, the MMPI-A was revised, published as the Minnesota Multiphasic Personality Inventory - Adolescent Restructured Form (MMPI-A-RF). Given the infancy of the extant MMPI-A-RF literature, the current dissertation sought to be one of the first criterion studies since the test manual to establish its relevant clinical correlates in a sample of youth referred for mental health services. Following in line with previous clinical correlate research, the psychometric properties of the MMPI-A-RF were determined. Under this approach, the present study bolstered support for the construct validity of the RC scales through the identification of clinically relevant, scale and item-level correlates. In particular, the RCd and RC4 evidenced especially strong convergent and discriminant validity. As a result, the current study highlighted the MMPI-A-RF's efficacy in detecting psychopathology along the broad externalizing and internalizing spectrum. In addition, the role of gender and its effect on MMPI-A-RF clinical interpretations were explored. Practical recommendations for ensuring a gender-specific approach to MMPI-A-RF interpretation were outlined.
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Reconfigurable Dual Band Power Amplifiers for Telemetry ApplicationsNath, Urmila 30 May 2019 (has links)
No description available.
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