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Strength and Performance of Steel Fiber Reinforced Concrete Post-Tensioned Flat PlatesRosenthal, Joshua Thomas 06 August 2019 (has links)
Load testing was performed on a one-third scale model steel fiber reinforced concrete post-tensioned flat plate. The specimen had nine 10ft x 10ft x 3in. bays along with a 2ft-6in. overhang. Distributed loading was applied with a whiffle tree loading system at each bay and overhang section. Throughout the test, crack widths, crack locations, deflections, concrete strains, and reinforcing bar strains were monitored. The post-tensioned flat plate was designed to just meet the maximum allowable stress requirements of ACI 318.
Minimal quantities of hairline cracks were observed after stressing the slab, and up through service-level loads, the cracks grew slightly in length and width. The slab behaved elastically through service-level loading. As factored-level loading was approached, the slab began to behave inelastically as indicated by both the load-deflection plots and the load-strain plots. A total ultimate load of 282psf (174psf of applied load) was reached when concrete crushing occurred. A 0.20in. wide full-length crack was observed running on the bottom surface of the slab between column lines 1 and 2, and a full-length crack was observed at column line 2 on the top surface of the slab. These two cracks were the leading contributors to the slab's failure.
The performance of the SFRC post-tensioned flat plate indicated that considerations should be made to remove requirements for negative moment reinforcement in post-tensioned flat plates when SFRC is used. Also, the requirements for positive moment reinforcement should be modified. Additionally, the SFRC post-tensioned flat plate exhibited excellent levels of ductility. More experimentation should be conducted to determine if the maximum tensile stress in ACI 318 can be increased for post-tensioned flat plates with SFRC. / Master of Science / Load testing was performed on a one-third scale model steel fiber reinforced concrete (SFRC) post-tensioned flat plate. Post-tensioned flat plates are a type of concrete structural system typically used as flooring. This system typically employs high-strength steel strands, which are stretched to introduce compression into the concrete, which helps prevent the onset of cracking. The specimen had nine 10ft x 10ft x 3in. bays along with a 2ft-6in. overhang. Distributed loading was applied with a whiffle tree loading system at each bay and overhang section. The whiffle tree loading system was used to allow actuators to spread out the vertical loading on the slab. During the test, crack widths, crack locations, deflections, concrete strains, and reinforcing bar strains were monitored. The post-tensioned flat plate was designed to just meet the maximum allowable stress requirements of the governing standard, ACI 318. Minimal quantities of hairline cracks were observed after stressing the slab, and up through service-level loads, the cracks grew slightly in length and width. As larger loads were applied, the cracks grew and the effects of these cracks on the slab were evidenced in the deflection and strain measurements. A total ultimate load of 282psf (174psf of applied load) was reached when concrete crushing occurred. A 0.20in. wide full-length crack was observed running on the bottom surface of the slab between column lines 1 and 2, and a full-length crack was observed at column line 2 on the top surface of the slab. These two cracks were a driving force in the slab’s failure. The performance of the SFRC post-tensioned flat plate indicated that considerations should be made to change the requirements for negative and positive moment reinforcement in post-tensioned flat plates when SFRC is used. Additionally, the SFRC post-tensioned flat plate exhibited great performance after significant cracking was present. More experimentation should be conducted to determine if the maximum allowable tensile stress in ACI 318 can be increased for post-tensioned flat plates with SFRC.
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Design and Analysis of an Innovative run-flat system for pneumatic tiresSaraswat, Abhishek 21 October 2024 (has links)
Pneumatic tires have been an essential part of the automobile since the early 20th century. Providing load carrying, braking, accelerating and turning capability as well as a certain degree isolation from the road, they fail to function without the presence of air pressure inside them. Run-flat tire systems allow the vehicle to continue running with reduced driving speeds for a certain specified range in case of loss of air pressure due to puncture or damage. In this work, the design of self-supporting and insert supported run-flat systems was approached using CAE.
Two tire FE models of sizes 175/70 R14 and 175/60 R18 were used in this study. All structural and thermal simulations were done using ABAQUS and ENDURICA software was used for fatigue life simulation. Distance travelled before failure was used as the primary parameter for design evaluation along with secondary parameters of contact patch area and contact pressure, tire temperature profiles and rolling resistance. Ride comfort and handling characteristics are important performance parameters for a tire. Thus, a limited study to quantify the effect of run-flat system on the ride and handling properties was also conducted. The target design values for maximum load were fixed according to ETRTO standards while the maximum operating speed and the desired mileage in deflated condition was fixed at 45 mph and 50 miles, respectively.
The initial part of the design process for the auxiliary supported design involved using a rigid cylindrical structure of varying height and thickness as a rim-mounted run-flat insert to get estimate of life of tire structure for different levels of deformation. The results were then used as input for designing a deformable rim mounted insert using reinforced rubber material.
For the self-supported design, the sidewall of the tire was modified to increase its section thickness from an average value of 5 mm in the original design to 10 mm and 15 mm by addition of rubber material. For each thickness value, three designs based on the location in the tire structure where the material addition began relative to the belt edges of the tire were created. The designs were compared in terms of their fatigue life and contact patch area.
For both types of run-flat designs, a candidate design, which satisfied the performance criteria, was found using the simulation results for the tire and run-flat system. It was concluded that a simulation-based approach can be used to design innovative run-flat systems for pneumatic tires. / Master of Science / Pneumatic tires have been an essential part of the automobile since the early 20th century. Providing load carrying, braking, accelerating and turning capability as well as a certain degree isolation from the road, they fail to function without the presence of air pressure inside them. Run-flat tire systems allow the vehicle to continue running with reduced driving speeds for a certain specified range in case of loss of air pressure due to puncture or damage. In this work, the design of self-supporting and insert supported run-flat systems was approached using computer aided design and simulation methods.
Two tire models of 14-inch and 18-inch wheel sizes were used in this study and distance travelled before failure when running in deflated condition was used as the primary parameter for design evaluation. Ride comfort and handling characteristics are important performance parameters for a tire. Thus, a limited study to quantify the effect of run-flat system on the ride and handling properties was also conducted. The maximum operating speed and the desired mileage in deflated condition was fixed as design targets at 45 mph and 50 miles, respectively.
For both types of run-flat designs, a candidate design, which satisfied the performance criteria, was found using the simulation results for the tire and run-flat system. It was concluded that a simulation-based approach can be used to design innovative run-flat systems for pneumatic tires.
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Práva a povinnosti člena společenství vlastníků jednotek / Rights and duties of a member of the association of owners of (residential) unitsŠebesta, David January 2012 (has links)
Rights and duties of the member of Flat owners association The purpose of my thesis is to focus on applicable law in the Czech Republic, particularly the Flat Ownership Act 72/1994 Coll. and analyze the rights and duties of the members of Unit owners association. The reason for my research is that the flat ownership and housing is one of the most important sector which affects the general public. The thesis is composed of three chapters, each of them dealing with aspects of flat ownership. Chapter one informs about historical context of housing and tries to introduce the flat ownership in general. Thesis provides information about contemporary regulation and also about relevant provisions of new coming civil code which will be applicable by 1 January 2014. Next chapter is introductory to Flat owners association and defines basic terminology. It explains a legal framework regulating the legal entity of the association and regulation of common property management. Including the internal structure and describes some relevant issues in respect with Flat owners association. Last chapter is most significant part of the thesis. The main aim is to analyze the rights and duties of flat owners and especially the members of flat owners association. The thesis concentrates on problems resulting from this...
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IMRT and Rotational IMRT (mARC) Using Flat and Unflat Photon BeamsSheta, Amal 16 August 2016 (has links) (PDF)
For more than 50 years
attening filters have been inserted into the beam path oflinacs to produce a uniform energy fluence distribution of the photon beam and make it suitable for clinical use. Recently, linacs without flattening fifilter (Flattening FilterFree - FFF) are increasingly used in radiotherapy because of its benefifits, e.g. high dose rate (2000 MU/min), reduced scattered and leakage radiation. Hypofractionated radiotherapy is interested in the high dose rate of FFF beams to shorten the treatment delivery time (TDT) especially the FFF beams have acceptable flatness at small fifieldsizes. Radiotherapy techniques that deliver intensity-modulated beams (IMBs), e.g.Tomotherapy, intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), deal with the non-uniformity of the FFF beam profifile and produce homogeneous dose to the target as FF beams do. Siemens modified the Artiste linac in order to enable photon beam delivery with and without a flattening fifilter. The VMAT version developed by Siemens for Artiste linacs as a novel radiation technique is a modulated arc therapy (mARC). mARC technique is available with single, double and multiple complete or partial arcs.
The aims of the current study were the determination of the main characteristics of 7 MV and 11 MV FFF photon beams in comparison with their corresponding 6 MV and 10 MV FF photon beams from Artiste digital linacs. Furthermore, IMRT planning comparisons using FF and FFF photon beams were performed using an Oncentra planning system. The performance of various mARC techniques were estimated and compared with Step and Shoot (S&S) IMRT by using a RayStation planning system. The mARC plans created by FF and FFF beams were evaluated to know which technique is the best. All the treatment plans were created for simple and complex shaped target volumes. The treatment plans are compared using two parameters - plan quality and treatment effi ciency. In addition to the planning study, the plan quality assurance of IMRT and mARC plans were performed using two difffferent volumetric quality assurance devices, Delta4 and Octavius 4D.
Removal of the flattening fifilter causes changes in the dosimetric features of photon beams. IMRT plans with and without flattening fifilter were clinically acceptable where both plans have similar quality. In comparison with IMRT-FF, IMRT-FFF plansrequire more MUs and for some clinical cases require longer TDT. mARC technique can deliver dose distributions that are comparable to S&S-IMRT and could be an alternative with a potential to improve the effi ciency of the IMRT treatment delivery.
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Development of a Flat Panel Detector with Avalanche Gain for Interventional RadiologyWronski, Maciej 03 March 2010 (has links)
A number of interventional procedures such as cardiac catheterization, angiography and the deployment of endovascular devices are routinely performed using x-ray fluoroscopy. To minimize the patient’s exposure to ionizing radiation, each fluoroscopic image is acquired using a very low x-ray exposure (~ 1 uR at the detector). At such an exposure, most semiconductor-based digital flat panel detectors (FPD) are not x-ray quantum noise limited (QNL) due to the presence of electronic noise which substantially degrades their imaging performance. The goal of this thesis was to investigate how a FPD based on amorphous selenium (a-Se) with internal avalanche multiplication gain could be used for QNL fluoroscopic imaging at the lowest clinical exposures while satisfying all of the requirements of a FPD for interventional radiology.
Towards this end, it was first determined whether a-Se can reliably provide avalanche multiplication gain in the solid-state. An experimental method was developed which enabled the application of sufficiently large electric field strengths across the a-Se. This method resulted in avalanche gains as high as 10000 at an applied field of 105 V/um using optical excitation. This was the first time such high avalanche gains have been reported in a solid-state detector based on an amorphous material.
Secondly, it was investigated how the solid-state a-Se avalanche detector could be used to image X-rays at diagnostic radiographic energies (~ 75 kVp). A dual-layered direct-conversion FPD architecture was proposed. It consisted of an x-ray drift region and a charge avalanche multiplication region and was found to eliminate depth-dependent gain fluctuation noise. It was shown that electric field strength non-uniformities in the a-Se do not degrade the detective quantum efficiency (DQE).
Lastly, it was determined whether the solid-state a-Se avalanche detector satisfies all of the requirements of interventional radiology. Experimental results have shown that the total noise produced by the detector is negligible and that QNL operation at the lowest fluoroscopic exposures is indeed possible without any adverse effects occurring at much larger radiographic exposures. In conclusion, no fundamental obstacles were found preventing the use of avalanche a-Se in next-generation solid-state QNL FPDs for use in interventional radiology.
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Development of a Flat Panel Detector with Avalanche Gain for Interventional RadiologyWronski, Maciej 03 March 2010 (has links)
A number of interventional procedures such as cardiac catheterization, angiography and the deployment of endovascular devices are routinely performed using x-ray fluoroscopy. To minimize the patient’s exposure to ionizing radiation, each fluoroscopic image is acquired using a very low x-ray exposure (~ 1 uR at the detector). At such an exposure, most semiconductor-based digital flat panel detectors (FPD) are not x-ray quantum noise limited (QNL) due to the presence of electronic noise which substantially degrades their imaging performance. The goal of this thesis was to investigate how a FPD based on amorphous selenium (a-Se) with internal avalanche multiplication gain could be used for QNL fluoroscopic imaging at the lowest clinical exposures while satisfying all of the requirements of a FPD for interventional radiology.
Towards this end, it was first determined whether a-Se can reliably provide avalanche multiplication gain in the solid-state. An experimental method was developed which enabled the application of sufficiently large electric field strengths across the a-Se. This method resulted in avalanche gains as high as 10000 at an applied field of 105 V/um using optical excitation. This was the first time such high avalanche gains have been reported in a solid-state detector based on an amorphous material.
Secondly, it was investigated how the solid-state a-Se avalanche detector could be used to image X-rays at diagnostic radiographic energies (~ 75 kVp). A dual-layered direct-conversion FPD architecture was proposed. It consisted of an x-ray drift region and a charge avalanche multiplication region and was found to eliminate depth-dependent gain fluctuation noise. It was shown that electric field strength non-uniformities in the a-Se do not degrade the detective quantum efficiency (DQE).
Lastly, it was determined whether the solid-state a-Se avalanche detector satisfies all of the requirements of interventional radiology. Experimental results have shown that the total noise produced by the detector is negligible and that QNL operation at the lowest fluoroscopic exposures is indeed possible without any adverse effects occurring at much larger radiographic exposures. In conclusion, no fundamental obstacles were found preventing the use of avalanche a-Se in next-generation solid-state QNL FPDs for use in interventional radiology.
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Městský polyfunkční dům na ulici Křížová, Brno / Multipurpose Town House on Křížová Street, BrnoJakůbková, Magdalena January 2011 (has links)
The project deals with the development of a gap site which forms the front line of a street in a city block. The building consists of two parts: in the southern corner a five-storey administrative building with a café and a patio is situated; the second, larger part is a block of flats with a commercial parterre connected with a pedestrain zone. The block of flats is – in accordance with the surrounding built-up area – designed as a house with access galleries, the majority of flats contain two storeys. Parking spaces are provided in the form of two underground storeys accessible from the inner block.
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Retracing the Journey of Franz Schubert’s Wanderer: Musical Fingerprints in the B-flat Sonata, D. 960Roggero, Amanda Marie 01 July 2004 (has links)
No description available.
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Městský dům - architektura kombinace funkcí / City House – Mixet Use ArchitectureSalva, Martin January 2013 (has links)
The project deals with completion a REC block buildings in Brno – Zábrdovice, defined by local roads. For the design of mass was used a porosity principle, when the site was covered with maximum static mass cutted by dynymic communication-optimal connections through the object. Object has five floors and a basement with garages and technical facilities. In the 1st floor and the part of 2nd floor are business premises, on the 2nd and 3rd level are administrative premises. On the part of a 3rd floor and in 4NP and 5th floor there are apartments. The foundations of an object is the reinforced concrete slab, the constuction systém is formed by reinforced-concrete columns with brick walls. Ceilings and staircases are monolithic reinforced concrete. Object is topped by a flat roof, part of the roof is greened.
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Nájemné bytu a faktory, které je ovlivňují ve městě Prostějov. / Apartment rent and the factors that influence it in the city of ProstějovNovák, Tomáš January 2015 (has links)
This thesis is focused on the analysis and comparison of rental apartments in Prostejov and all the factors that have the level of rents in the area of influence. The work presents textual and graphical part of a designated location according to the amount of rent in various parts of the city Prostejov flats of sizes 1 + 1, 1 + KK, 2 + 1, 2 + KK, 3 + 1, 3 + KK. These dispositions are examined and appreciation is shown in tables and graphs. The result is a calculation and comparison of individual dispositions rent flats and assess the factors that have influence on the price.
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