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Návrh tvářecího nástroje a zařízení k vystřižení podložky / Design of Forming Tool and Machinery for Couting out of PadKolář, Milan January 2010 (has links)
The Diploma Thesis presents a draft of designated automatic apparatus for cutting out and assembling pads for pressure control valve (DRV2). The theoretical chapter of the Thesis contains selected findings from theory and technology for material cutting. The next chapter contains design solutions for a designated apparatus for cutting and assembling pressure control valves. The pads are etched from 0,08 mm steel plates X2CrNi Mol7-12-2. The shape of the pads is etched on a 35mm-wide belt that is wound up onto a drum. The draft of this new technological facility has been elaborated in accordance with the most suitable technological variant. The cutting tool is made of steel 19 437 that is thermally processed at HRC 62-4. Estimated annual volume of production series is 2 mil. pcs. The cutting and assembly processes are executed with the aid of this designated automatic apparatus.
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Fail Operational Controls for an Independent Metering ValveRannow, Michael January 2016 (has links)
As intelligent hydraulic systems with embedded sensors become more ubiquitous, the real or perceived reliability challenge associated with sensors must be addressed to encourage their adoption. In this paper, a fault-tolerant control strategy for an intelligent independent metering valve that allows continued operation if a sensor fails is described. The twin-spool valve example utilizes position sensors to stabilize the spool positions and eliminate hysteresis, and pressure sensors to provide digital pressure compensation, electronic load sensing, and other features. An independent metering valve has redundancy provided by four sensors working together to control the flow into and out of a single actuator. Although two sensors are needed to control the flow through a spool, the controller can be reconfigured to ensure the flow is always controlled on the spool with both sensors working. To accomplish this, the concept of cross-port pressure control is introduced that uses the faulty side of the valve to maintain constant pressure on the non-faulty side. By maintaining a constant pressure, the flow in and out of the actuator are balanced. Experimental results on the boom of a backhoe demonstrate the operation of the fault tolerant control strategy.
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Investigations into Pressure Profile and Pressure Control in Wrist-Worn Health Monitoring DevicesBlack, Roger McAllister 02 August 2022 (has links) (PDF)
To aid in the design of future wearable health devices (WHDs), contact pressure between the distal forearm (wrist) and two different wrist-worn devices was investigated in this work. The first device included eight force sensors arranged in series along the length of a wristband to measure the pressure profile. The band also included a tensioner device for manually tightening the band while on a wrist. Testing was done on dummy wrists and the results were statistically significant supporting the hypothesis that areas of the wrist with lower radius of curvature will experience higher contact pressures generally and a faster rate of change in pressure as the band is tightened. The second band included a controller, actuator, and force sensors for actively controlling the contact pressure of a photoplethysmography (PPG) sensor on the wrist during user motion. A total of eight tests were performed on six human subjects to estimate previously unknown design parameters related to contact pressure control of a wrist-worn device. Participants were asked to perform several actions including tapping their finger at different rates, tossing a ball, wrist flexion and extension, and making a fist. The design parameters investigated were system stiffness, range in contact pressure caused by motion, range of motion in the radial direction required to maintain a desired pressure, arterial pulse pressure amplitude and its relation to pressure tolerance, and system response time required to maintain a constant pressure. System stiffness was observed to be greater during motion (dynamic) than during rest (static) and to increase with increasing contact pressure. The change in contact pressure caused by motion was around 18 kPa in some cases and the maximum range of motion to maintain a contact pressure was about 7 mm. The arterial pulse pressure amplitude ranged between 0.05 to 0.3 kPa. It was estimated that a maximum sensor platform speed of 30 mm/s or greater is required to maintain a constant contact pressure during large motion actions such as flexing the wrist up and down. Finally, no significant differences were observed in the PPG signal between states in which the contact pressure was controlled vs. not controlled.
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Non-pharmacological interventions to achieve blood pressure control in African patients: a systematic reviewCernota, Monique, Kroeber, Eric Sven, Demeke, Tamiru, Frese, Thomas, Getachew, Sefonias, Kantelhardt, Eva Johanna, Ngeh, Etienne Ngeh, Unverzagt, Susanne 23 January 2023 (has links)
Objectives This systematic review aims to evaluate the
evidence of non-pharmacological
strategies to improve
blood pressure (BP) control in patients with hypertension
from African countries.
Design We performed a systematic review and searched
Medline, Central, CINAHL and study registers until June
2020 for randomised studies on interventions to decrease
BP of patients with hypertension in African countries.
We assessed the study quality using the Cochrane risk
of bias tool and narratively synthesised studies on non-pharmacological
hypertension interventions.
Setting We included studies conducted in African
countries.
Participants Adult African patients with a hypertension
diagnosis.
Interventions Studies on non-pharmacological
interventions aiming to improve BP control and treatment
adherence.
Outcomes Main outcomes were BP and treatment
adherence.
Results We identified 5564 references, included 23 with
altogether 18 153 participants from six African countries.
The studies investigated educational strategies to improve
adherence (11 studies) and treatment by healthcare
professionals (5 studies), individualised treatment
strategies (2 studies), strategies on lifestyle including
physical activity (4 studies) and modified nutrition (1
study). Nearly all studies on educational strategies stated
improved adherence, but only three studies showed a
clinically relevant improvement of BP control. All studies
on individualised strategies and lifestyle changes resulted
in clinically relevant effects on BP. Due to the type of
interventions studied, risk of bias in domain blinding of
staff/participants was frequent (83%). Though incomplete
outcome data in 61% of the studies are critical, the
general study quality was reasonable.
Conclusions The identified studies offer diverse
low-cost
interventions including educative and task-shifting
strategies, individualised treatment and lifestyle
modifications to improve BP control. Especially trialled
physical activity interventions show clinically relevant BP
changes. All strategies were trialled in African countries
and may be used for recommendations in evidence-based
guidelines on hypertension in African settings.
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Contribuicoes para melhoria das metodologias de avaliacao de choque termico pressurizado em vasos de pressao de reatores PWRGOMES, PAULO de T.V. 09 October 2014 (has links)
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10555.pdf: 13498632 bytes, checksum: a2f985eebcd01db42fa692b0aad0df6d (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Contribuicoes para melhoria das metodologias de avaliacao de choque termico pressurizado em vasos de pressao de reatores PWRGOMES, PAULO de T.V. 09 October 2014 (has links)
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10555.pdf: 13498632 bytes, checksum: a2f985eebcd01db42fa692b0aad0df6d (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Design studies for stand off bomb detectionMatthew, Christopher P. January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / William L. Dunn / A prototype system for detecting explosives at standoff distances, using a signature based radiation scanning approach, is being developed at Kansas State University. The prototype will incorporate both a machine x-ray source and a machine neutron source to generate signatures from unknown samples of material. These signatures can be compared to templates measured or calculated from known explosive samples using a figure-of-merit. The machine neutron source uses the fusion of deuterium and tritium to create 14.1 MeV neutrons. Due to its radioactivity, the tritium must be sealed within the system. A new method of controlling the gas pressure with the DT generator was developed using a Zr-V-Fe getter supplied by a commercial firm. The shielding and collimation of the 14.1 MeV neutron source is accomplished using layers of steel, high-density polyethylene and borated high-density polyethylene. This thesis describes the development of the gas control method for the sealed neutron source, design studies for the shielding and collimation of the neutron source and modifications made to the building in which the prototype is being housed.
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Utilizing Valvetrain Flexibility to Influence Gas Exchange and Reduce Reliance on Exhaust Manifold Pressure Control for Efficient Diesel Engine OperationKalen Vos (6787271) 02 August 2019 (has links)
Environmental health awareness has elevated in recent years alongside the evidence that supports the need to mitigate harmful greenhouse gas (GHG) emissions
from non-renewable energy resources. The transportation sector alone significantly
contributes to the pollutants on a global scale. Although it is commonly used for
its superior energy-density and fuel efficiency, diesel engines are a significant portion
of the transportation sector that contributes to these pollutants. As a result, this
motivates novel research to simultaneously drive fuel efficiency improvements and
emissions reductions. <div><br></div><div>The aftertreatment system for a diesel engine is critical in reducing the amount of
harmful tailpipe emissions. Efficient operation of these aftertreatment systems generally requires elevated temperatures of 250◦C or above. In this effort, a flexible valvetrain will be utilized to demonstrate fuel-efficient strategies via intake valve closure
(IVC) modulation at elevated speeds and loads. In addition, thermal management
strategies will be demonstrated at low-to-moderate loads via cylinder deactivation
(CDA), cylinder cutout, exhaust valve opening (EVO) modulation, and high-speed
idle operation.</div><div><br></div><div>At elevated engine speeds, late intake valve closure (LIVC) enables improved
cylinder filling via a dynamic charging effect. It is experimentally and analytically
demonstrated that LIVC at 2200 RPM and 7.6 bar to 12.7 bar BMEP can be used to
increase the volumetric efficiency and enable higher exhaust gas recirculation fractions
without penalizing the air-to-fuel ratio. As a result, efficiency improving injection advances are implemented to achieve 1.2% and 1.9% fuel savings without sacrificing NOx penalties. In order to implement the LIVC benefits on a cammed engine,
production-viable valve profile solutions were investigated. It is demonstrated that
lost-motion-enabled and/or added-motion-enabled boot shape profiles are capable of
improving volumetric efficiency at elevated engine speeds and loads. These profiles
were also considered for one (of two) -valve modulation and two-valve modulation.
Nearly 95% of the volumetric efficiency benefits are possible using production-viable
boot or phase profiles, while 80% of the benefits are possible for single-valve modulation. </div><div><br></div><div>At curb idle, CDA and cylinder cutout operation realize stay-warm aftertreatment
thermal management improvements by leveraging their impact on the gas exchange
process. Specifically, cylinder cutout demonstrates 17% fuel savings, while CDA
demonstrates 40% fuel savings, over the conventional six-cylinder thermal calibration. Additionally, the performance of cylinder cutout is subject to the geometry of
the exhaust manifold, location of the EGR loop, and ability to control the exhaust
manifold pressure. </div><div><br></div><div>Elevating the idle speed, while maintaining the same idle load, enables improved
aftertreatment warm-up performance with engine-out NOx and PM levels no higher
than a state-of-the-art thermal calibration at conventional idle operation. Elevated
idle speeds of 1000RPM and 1200 RPM, compared to conventional idle at 800 RPM,
realized 31% to 51% increase in exhaust flow and 25◦C to 40◦C increase in engine-out
temperature, respectively. Additional engine-out temperature benefits are experimentally demonstrated at all three idle speeds considered (800, 1000, and 1200 RPM),
without compromising the exhaust flow rates or emissions, by modulating the EVO
timing. </div><div><br></div><div>At low-to-moderate loads modern diesel engines manipulate exhaust manifold
pressures to drive EGR and thermally manage the aftertreatment. In these engines
exhaust manifold pressure control is typically achieved via either a valve after the turbine, a variable geometry turbine, or wastegating. It is experimentally demonstrated that valvetrain flexibility enables efficient engine and aftertreatment operation without requiring exhaust manifold pressure control. Specifically, IVC modulation and
CDA at elevated engine speeds, along with EVO modulation, CDA, and internal EGR
at low engine speeds can match, or improve, efficiency and thermal management performance compared to a stock thermal calibration that requires exhaust manifold
pressure control.<br></div>
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Evaluating Tire Pressure Control System to Improve Productivity and Mitigate Pavement DamageMabood, Fazal 08 September 2008 (has links)
The introduction of the use of Tire Pressure Control Systems (TPCS) to improve the productivity of the Canadian trucking industry is gaining momentum. The imposition of seasonal load restrictions (SLR) on the thaw-weakened secondary roads interrupts the transportation of raw materials to processing facilities For the forestry industry in particular, this has very significant impacts on productivity and costs. FPInnovations-Feric Division (Feric) has investigated the potential for TPCS-equipped trucks to travel with full, legal loading during the SLR period without accelerating road wear and tear. The TPCS monitors and adjusts the inflation pressure of the trucks’ tires while driving and allows the operator to optimize the inflations for changes in loading, travel speed, or road quality encountered in the trip.
This thesis describes an investigation to determine whether TPCS can be used to mitigate traffic generated damage to secondary roads and also reduce the need to implement load restrictions. The project involves a partnership with the Ontario Ministry of Transportation Ontario (MTO), Forest Engineering Research Institute of Canada (FERIC), Ontario Ministry of Natural Resources (MNR) and the Centre for Pavement and Transportation Technology (CPATT) located at the University of Waterloo.
The thesis will describe the methodology, design, and instrumentation of the two test sites which are located in Dryden, Ontario and Chapleau, Ontario. In addition, repeated Portable Falling Weight Deflectometer (PFWD) testing is being carried out at these sites and the initial results of this examination and associated impacts of the environment and traffic on the road will be presented. This study also involves looking into the reliability of using the portable FWD, offering a lower cost alternative instead of the trailer mounted FWD to monitor pavement strength for the identification the SLR period. The use of innovative sensors and data collection techniques are proving to be very informative and are advancing pavement engineering knowledge. Moreover, the thesis is aimed at exploring the possibilities of achieving the current objectives of the government DOTs such as TPCS potential for addressing the timber industry in crisis, reduced road maintenance budgets, and global warming increasing road damage.
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Evaluating Tire Pressure Control System to Improve Productivity and Mitigate Pavement DamageMabood, Fazal 08 September 2008 (has links)
The introduction of the use of Tire Pressure Control Systems (TPCS) to improve the productivity of the Canadian trucking industry is gaining momentum. The imposition of seasonal load restrictions (SLR) on the thaw-weakened secondary roads interrupts the transportation of raw materials to processing facilities For the forestry industry in particular, this has very significant impacts on productivity and costs. FPInnovations-Feric Division (Feric) has investigated the potential for TPCS-equipped trucks to travel with full, legal loading during the SLR period without accelerating road wear and tear. The TPCS monitors and adjusts the inflation pressure of the trucks’ tires while driving and allows the operator to optimize the inflations for changes in loading, travel speed, or road quality encountered in the trip.
This thesis describes an investigation to determine whether TPCS can be used to mitigate traffic generated damage to secondary roads and also reduce the need to implement load restrictions. The project involves a partnership with the Ontario Ministry of Transportation Ontario (MTO), Forest Engineering Research Institute of Canada (FERIC), Ontario Ministry of Natural Resources (MNR) and the Centre for Pavement and Transportation Technology (CPATT) located at the University of Waterloo.
The thesis will describe the methodology, design, and instrumentation of the two test sites which are located in Dryden, Ontario and Chapleau, Ontario. In addition, repeated Portable Falling Weight Deflectometer (PFWD) testing is being carried out at these sites and the initial results of this examination and associated impacts of the environment and traffic on the road will be presented. This study also involves looking into the reliability of using the portable FWD, offering a lower cost alternative instead of the trailer mounted FWD to monitor pavement strength for the identification the SLR period. The use of innovative sensors and data collection techniques are proving to be very informative and are advancing pavement engineering knowledge. Moreover, the thesis is aimed at exploring the possibilities of achieving the current objectives of the government DOTs such as TPCS potential for addressing the timber industry in crisis, reduced road maintenance budgets, and global warming increasing road damage.
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