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Artykuły w czasopismach na temat "VARING LOAD CONDITIONS"
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Lee. "Analysis of segment lining cracking load considering axial force by varying boundary condition". Journal of Korean Tunnelling and Underground Space Association 16, nr 2 (2014): 173. http://dx.doi.org/10.9711/ktaj.2014.16.2.173.
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Palmer, Kyle D., Mark A. Severy, Charles E. Chamberlin, Anthony J. Eggink i Arne E. Jacobson. "Performance Analysis of a Biomass Gasifier Genset at Varying Operating Conditions". Applied Engineering in Agriculture 34, nr 1 (2018): 135–43. http://dx.doi.org/10.13031/aea.12414.
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Abstract. An All Power Labs PP20 gasifier generation set (Berkeley, Calif.) was tested to evaluate its suitability for powering biomass conversion technologies (BCT) at remote forest operations sites. Feedstock of the species tanoak (), coast redwood (), and Douglas fir () were tested at moisture contents of 15% and 25% (wet basis). The PP20 was connected to a load bank with five different load profiles designed to simulate possible BCT loads. Two parameters of power quality, voltage variability, and frequency deviation, were determined to be within acceptable limits. The unit also successfully powered a remote biochar operation in Branscomb, California. Emissions of the PP20, when compared to diesel generator regulations, would meet non-methane hydrocarbons (NMHC) and NOX requirements but exceed the CO emissions limits by a factor of ten. The CO emissions could be reduced by adding a catalytic converter. The results indicate that it is possible to use a PP20 unit to provide electric power for the highly variable loads of a BCT system. Keywords: Bioenergy, Biomass conversion technology, Gasification, Renewable energy.
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Rittmann, Bruce E. "The Effect of Load Fluctuations on the Effluent Concentration Produced by Fixed-Film Reactors". Water Science and Technology 17, nr 2-3 (1.02.1985): 45–52. http://dx.doi.org/10.2166/wst.1985.0118.
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Although time-varying loads to biological treatment processes are common, typical kinetic models are based on steady-state loads and conditions. This paper uses nonsteady-state kinetics to demonstrate the impact of load variations on the effluent concentration and load from fixed-bed biofilm reactors. The different responses for reactors having average loads that are high, intermediate, and low are compared. In most cases, time-varying input loading, in comparison with steady input loading, causes an increase in average effluent concentration; however, certain combinations of load variation and reactor type allow better performance than do steady-state loads.
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Sato, J. A., F. J. Vecchio i H. M. Andre. "Scale-model testing of reinforced concrete under impact loading conditions". Canadian Journal of Civil Engineering 16, nr 4 (1.08.1989): 459–66. http://dx.doi.org/10.1139/l89-075.
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Aspects of scaling theory relating to the response of reinforced concrete structures under impact load conditions are reviewed. Details for modelling concrete and reinforcement, to be consistent with similitude requirements, are also discussed. A test program is described in which models of varying size were constructed, drop tested, and compared with prototype response. An analysis of the test data is made, indicating that, within certain limitations, the predictions of scaling theory are applicable to reinforced concrete subjected to extreme impact loads. Key words: cracking, impact, loads, modelling, reinforced concrete, scaling, stresses, structures, tests.
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Arseneau, R. "The performance of demand meters under varying load conditions". IEEE Transactions on Power Delivery 8, nr 4 (1993): 1708–11. http://dx.doi.org/10.1109/61.248277.
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Zeng, Zhiping, Guanghui Hu, Xiangdong Huang, Weidong Wang, Ayoub Abdullah Senan Qahtan, Abdulmumin Ahmed Shuaibu i Jundong Wang. "Statics performance of heavy-haul railway low-vibration track (LVT) under varying loading condition with the finite element method". Science Progress 104, nr 4 (październik 2021): 003685042110363. http://dx.doi.org/10.1177/00368504211036330.
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Low-Vibration Tracks (LVTs) are widely used in subway tunnels for their excellent performance, but the application in heavy-duty railways still requires a lot of feasibility studies. In this study, the statics performance of LVT under different axle loads, load direction, and load position is explored using the finite element software Abaqus. The Timoshenk beam element and nonlinear spring element 3D solid element are used to represent rails, fasteners, and the other track structure respectively. The paper established the finite element model of LVT to study the mechanical characteristics of low vibration track structure under varying loading condition. The applied loads are determined according to the Heavy-Haul Railway Track Structure Design Code. The results shows: (1) The deformation and stress of the LVT structure show a linear relationship with the increase of the axle load. (2) Slab end loading and lateral load are more unfavorable to the stress and deformation of the track structure. When slab end is loaded with vertical load, the vertical load is distributed on four supporting blocks along the longitudinal direction with a ratio of 1:4:4:1, and the lateral direction is mainly borne by two adjacent fastener nodes with the total load proportion of 47% and 47% respectively. (3) The LVT structure can guarantee the safety of static performance under 30 t axle load and the maximum axle load should not exceed 36 t. The paper provides a guideline for the construction and maintenance of LVT structure in heavy haul railway.
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Feiyan Fan, Feiyan Fan, Jiazhen Hou Feiyan Fan i Tanghuai Fan Jiazhen Hou. "Fault Diagnosis under Varying Working Conditions with Domain Adversarial Capsule Networks". 電腦學刊 33, nr 3 (czerwiec 2022): 135–46. http://dx.doi.org/10.53106/199115992022063303011.
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<p>Most existing studies that develop fault diagnosis methods focus on performance under steady operation while overlooking adaptability under varying working conditions. This results in the low generalization of the fault diagnosis methods. In this study, a novel deep transfer learning architecture is proposed for fault diagnosis under varying working conditions. A modified capsule network is developed by combining the domain adversarial framework and classical capsule network to simultaneously recognize the machinery fault and working conditions. The novelty of the proposed architecture mainly lies in the integration of the domain adversarial mechanism and capsule network. The idea of the domain adversarial mechanism is exploited in transfer learning, which can achieve a promising performance in cross-condition fault diagnosis tasks. With the novel architecture, learned features exhibit identical or very similar distributions in the source and target domains. Hence, the deep learning architecture trained in one working condition can be applicable to discriminative conditions without being hindered by the shift between the two domains. The proposed method is applied to analyze vibrations of a bearing system acquired under different working conditions, i.e., loads and rolling speed. The experimental results indicate that the proposed method outperforms other state-of-the-art methods in fault diagnosis under varying working conditions.</p> <p> </p>
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Mullings, Hannah, i Tim Stallard. "Impact of spatially varying flow conditions on the prediction of fatigue loads of a tidal turbine". International Marine Energy Journal 5, nr 1 (21.06.2022): 103–11. http://dx.doi.org/10.36688/imej.5.103-111.
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Site development for tidal turbines relies upon a good understanding of the onset flow conditions, with disk averaged velocity typically used as a reference to define turbine power and mean loading. This work investigates the variation of onset flow conditions which occur for the same disk averaged velocity. Analysis builds upon data previously acquired during the measurement campaign conducted for the ReDAPT project using bed mounted ADCPs \cite{Sellar2018}. These measurements define the turbulence characteristics and vertical shear profiles over the rotor plane which are incorporated into an efficient blade element method for prediction of unsteady blade loads. This method allows efficient calculation of blade loading for multiple onset shear and turbulence profiles, each with the same disk average velocity, to determine the cyclic loading which contributes towards fatigue. Predictions of fatigue loads from measured profiles are compared with predictions from profiles predicted for the same location with a MIKE3 model \cite{Gunn2014}. Within the water depth two vertical positions are analysed, with vertical shear profiles from measurements and a multi-parameter model used to define the onset. For a near-bed location, use of the averaged predicted velocity profiles neglecting variation of turbulence intensity with flow-speed provides fatigue loads to within 1\% of predictions obtained using all measured profiles of velocity and corresponding turbulence intensity. For the near-surface location, the same approach under predicts fatigue loads by 16-19\%. This is partly due to the occurrence of a wider range of turbulence intensities. Since this is nearly constant with flow-speed a scaling factor is applied to load cycles from predicted profiles to estimate the aggregated fatigue load obtained using all measured conditions, providing confidence that accumulated fatigue loads can be predicted efficiently from velocity profiles obtained from shallow water models.
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Antoniadou, I., G. Manson, W. J. Staszewski, T. Barszcz i K. Worden. "A time–frequency analysis approach for condition monitoring of a wind turbine gearbox under varying load conditions". Mechanical Systems and Signal Processing 64-65 (grudzień 2015): 188–216. http://dx.doi.org/10.1016/j.ymssp.2015.03.003.
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Pichler, Kurt, Edwin Lughofer, Markus Pichler, Thomas Buchegger, Erich Peter Klement i Matthias Huschenbett. "Fault detection in reciprocating compressor valves under varying load conditions". Mechanical Systems and Signal Processing 70-71 (marzec 2016): 104–19. http://dx.doi.org/10.1016/j.ymssp.2015.09.005.
Pełny tekst źródłaRozprawy doktorskie na temat "VARING LOAD CONDITIONS"
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Malmgren, Lars. "Shotcrete rock support exposed to varying load conditions". Licentiate thesis, Luleå, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17604.
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Field and laboratory tests and analyses This Licentiate thesis deals with the function of shotcrete as rock support. An extensive failure mapping of shotcrete in the Kiirunavaara mine has been conducted to improve the understanding of the performance of shotcrete. Furthermore, the adhesion strength obtained for different types of scaling/cleaning methods and the relationship between adhesion and compressive strength were investigated in field tests in the mine. The failure mapping showed that most of the observed failures of shotcrete are in areas with a thin shotcrete layer (Godkänd; 2001; 20070313 (ysko)
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Zhu, Dan. "Electric Distribution Reliability Analysis Considering Time-varying Load, Weather Conditions and Reconfiguration with Distributed Generation". Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/26557.
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This dissertation is a systematic study of electric power distribution system
reliability evaluation and improvement. Reliability evaluation of electric power systems
has traditionally been an integral part of planning and operation. Changes in the electric
utility coupled with aging electric apparatus create a need for more realistic techniques
for power system reliability modeling.
This work presents a reliability evaluation technique that combines set theory and
Graph Trace Analysis (GTA). Unlike the traditional Markov approach, this technique
provides a fast solution for large system reliability evaluation by managing computer
memory efficiently with iterators, assuming a single failure at a time. A reconfiguration
for restoration algorithm is also created to enhance the accuracy of the reliability
evaluation, considering multiple concurrent failures. As opposed to most restoration
simulation methods used in reliability analysis, which convert restoration problems into
mathematical models and only can solve radial systems, this new algorithm seeks the
reconfiguration solution from topology characteristics of the network itself. As a result
the new reconfiguration algorithm can handle systems with loops.
In analyzing system reliability, this research takes into account time-varying load
patterns, and seeks approaches that are financially justified. An exhaustive search scheme
is used to calculate optimal locations for Distributed Generators (DG) from the reliability
point of view. A Discrete Ascent Optimal Programming (DAOP) load shifting approach
is proposed to provide low cost, reliability improvement solutions.
As weather conditions have an important effect on distribution component failure
rates, the influence of different types of storms has been incorporated into this study.
Storm outage models are created based on ten yearsâ worth of weather and power outage
data. An observer is designed to predict the number of outages for an approaching or on
going storm. A circuit corridor model is applied to investigate the relationship between
power outages and lightning activity.Ph. D.
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Karhu, A. (Anssi). "Behavior of the RF power amplifier under a varying load condition in 5G mMIMO base station". Master's thesis, University of Oulu, 2018. http://urn.fi/URN:NBN:fi:oulu-201809122771.
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RF power amplifier is located at the backend of the transmitter before the filter and the antenna. To ensure ideal operation, known output impedance of the power amplifier is matched to the load impedance with help of matching network. Load impedance is traditionally provided by the circulator which has good isolation properties and stable load property. Higher frequencies are investigated in future 5G technology to obtain wider available bandwidths and meet increased capacity requirements. Higher frequencies have shorter wavelength which leads to smaller cell sizes due to their poorer propagation capability. As many RF components, also antennas have properties that are relative to wavelength. Higher frequency thus enables to integrate more antenna elements to base station structure, which is called massive MIMO (mMIMO) structure. By adjusting excitation signals of each element, wanted beam forms and beam directions are achieved. The possibility for the removal of the circulator from the power amplifier output was investigated in this thesis. In mMIMO structure number of transmitting branches is huge, so there is potential to achieve cost savings and increase the integration level if the removal is feasible. However, transistor output would be then altered to highly frequency and power dependent load, because the antenna input impedance is affected by the coupling effects from neighboring elements as a function of beam steering functionality. Thanks to good isolation properties of the circulator, power amplifier is not altered to that in traditional base station design. Additionally, circulator protects the transistor from reflecting waves, as they are routed to the termination. The device under test was optimized to 3.4 GHz-3.6 GHz frequency band and was connected as a balanced structure. The goal in this thesis was to investigate how the removal is changing the behavior of the power amplifier compared to the design where the circulator exists. Investigation was carried out by examining the basic RF performance parameters and quality of the feedback response for the digital pre-distorter (DPD). Simulation models turned out to be inadequate to simulate the performance under a varying load condition properly and accurate correlation between simulations and hardware measurements was not achieved. However, hardware implementation and measurement results showed up a potential, but there also occurred a big variation over the operation bandwidth. There occurred 8.3% unit variation in the efficiency figures in the circulatorless design over the bandwidth while it was just 2% units in the design where circulator existed. Peak power quantities varied 1.5 dB and. 0.5 dB respectively. Also, the effect on the DPD feedback response was more severe than expected as the ripple in the response was 4 dB in the circulatorless design while it was within acceptable limits in the design where the circulator existed. Therefore, more investigation would be needed in the future to ensure the proper performance over the bandwidthTehovahvistin sijaitsee tukiasemarakenteen lähetysketjun loppupäässä ennen suodatinta ja antennia, ja on tukiaseman eniten tehoa kuluttava osa. Jotta tehovahvistin toimisi ideaalisesti, sen tiedetty lähtöimpedanssi sovitetaan sovitusverkon välityksellä kuormaimpedanssiin, joka perinteisesti on hyvän isolaatiokyvyn omaavan sirkulaattorin tuottama kuorma. Tulevaisuuden 5G-teknologiassa signaalitaajuus tulee useimmissa tapauksissa kasvamaan, sillä vapaata taajuuskaistaa ei juurikaan ole enää saatavilla nykyisillä langattoman tiedonsiirron käyttöön osoitetuilla taajuusalueilla. Tätä lisäkapasiteettia on välttämätöntä saada, jotta huimasti kasvavaan langattoman tiedonsiirron tarpeeseen kyetään vastaamaan. Korkeammat taajuudet tarkoittavat lyhyempiä aallonpituuksia, joiden myötä signaalin etenemiskyky heikkenee ja tukiasemien solukoot pienenevät väistämättä. Kuten RF-komponentit usein, myös antennielementit omaavat useita aallonpituudesta riippuvia parametreja. Täten taajuuden kasvattaminen sallii myös antennielementtien määrän kasvattamisen, jolloin puhutaan Massive MIMO (mMIMO) rakenteessa. Näiden antennielementtien välisiä konfiguraatioita muuttamalla saadaan aikaan haluttuja keilakuvioita ja kyetään myös suuntaamaan keiloja haluttuun suuntaan. Tätä kutsutaan keilanmuodostukseksi (engl. beamforming). Tässä työssä tutkittiin päätesirkulaattorin poistamisen mahdollisuutta tehovahvistimen lähdöstä 5G mMIMO -tukiasemarakenteessa. Lähetysketjujen suuresta määrästä johtuen integrointitason kasvattaminen omaa suuren potentiaalin kustannussäästöihin, ja sirkulaattorin poistaminen varsin isokokoisena ja hintavana komponenttina olisi myös yksi vaihtoehto niiden saavuttamiseksi. Tällöin tehovahvistimen näkemä kuorma on kuitenkin taajuuden ja tehon funktiona vaihteleva, sillä antennin tuloimpedanssiin vaikuttaa esimerkiksi kytkeytymisefektit viereisistä antennielementeistä eri keilanmuodostus konfiguraatioiden funktiona. Perinteisessä toteutuksessa sirkulaattori siis stabiloi hyvän isolaatio-ominaisuutensa ansiosta tätä vaihtelevaa kuormaa tehovahvistimen näkökulmasta, sekä myös suojaa tehovahvistinta takaisin heijastuvilta aalloilta. Työ toteutettiin tutkimalla, miten sirkulaattorin poisto vaikuttaa tehovahvistimen toimintaan verrattuna toteutukseen jossa sirkulaattori on olemassa. Tutkittava integroitu Doherty vahvistin oli optimoitu taajuusalueelle 3,4–3,6 GHz ja oli kytketty balansoiduksi rakenteeksi. Työssä käytetyt simulointimallit osoittautuivat liian vajavaisiksi, joten tehovahvistimen suorituskykyä ei pystytty täysin mallintamaan. Käytännön mittaukset osoittivat kuitenkin potentiaalia, mutta myös suurta suorituskykyvaihtelua taajuuskaistan yli. Hyötysuhdeluvut vaihtelivat 8,3% yksikköä ja piikkiteho kyvykkyys 1,5 dB taajuuskaistan yli toteutuksessa jossa sirkulaattori oli poistettu vastaavien lukujen ollessa 2% yksikköä ja 0,5 dB toteutuksessa jossa sirkulaattori oli olemassa. Lisää kehitys- ja tutkimustyötä tarvittaisi, jotta tehovahvistimen käyttäytyminen saataisi varmistettua koko taajuuskaistan ylitse
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Rai, Manpreet Kaur. "Understanding the role of the episodic buffer of working memory in inferential reading comprehension in L1 and L2 readers under varying conditions of cognitive load and domain knowledge". Diss., Kansas State University, 2014. http://hdl.handle.net/2097/18232.
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Doctor of PhilosophyDepartment of Psychological Sciences
Richard Jackson Harris
In recent years, Baddeley (2010) has added a new component, the episodic buffer, to his Working Memory (WM) model. The episodic buffer binds information from long-term memory (LTM) to the central executive but has been researched very little, especially with respect to its use with a second language. In fact, Juffs and Harrington (2011) stated, “To date there has been no research on the possible role of the episodic buffer in L2 learning and use” (p. 140). One goal of this study was to do just that. Domain knowledge (DK) in baseball (Experiment 1) and English proficiency levels (Experiment 2) were used as proxies for difficulty level to study how inference processing under different conditions of domain knowledge and cognitive load in native (L1) and non-native (L2) English readers contribute to understanding the episodic buffer. In Experiment 1, 67 participants varying in domain knowledge about baseball read stories related to baseball with or without a concurrent cognitive load task of responding to tones while reading; they then answered comprehension questions of varying degrees of inferential difficulty. In Experiment 2, three groups varying in English reading proficiency, split into groups based on their lexical decision task scores (72 native, 40 intermediate, 40 beginner readers) read general stories with or without cognitive load and answered comprehension questions requiring varying degrees of inferential difficulty. Accuracy and Reaction Time (RT) were differentially affected by working memory (OSpan), cognitive load, and inferential complexity. In Experiment 1, greater DK explained variance in effectiveness (accuracy) and efficiency (RT) as inferential complexity increased. In Experiment 2 OSpan was needed even at lower levels of inferential complexity for beginning readers. Surprisingly, for both experiments, participants responded faster under cognitive load conditions, although not at the expense of accuracy. This suggests that the episodic buffer is important for different levels of DK and proficiency, especially as the task becomes more difficult. Theoretical and practical implications of these findings are discussed.
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Alapää, Pär. "Remediation of Contaminated Groundwater Using a SpinChem® Rotating Bed Reactor : Competitive Sorption of Metal(loid)s in Complex Solutions under Varying Geochemical Conditions". Thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-69987.
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The potential of utilizing a new form of chemical processing technology called SpinChem® Rotating Bed Reactor (RBR), in combination with different reactive materials, for the purpose of remediating multi-contaminated aquifers under changing environmental conditions, was investigated using laboratory studies and geochemical models. Four different reactive materials, or combinations thereof, were tested: heat-treated peat powder combined with zero-valent iron (ZVI); IronPeat, which consists of peat powder coated with a ferriferous hydrosol (FFH); and a powdered steel waste product. Results showed that the powdered steel waste was compatible with the technology while the peat-based sorbents were not. However, there were no indications that the kinetics of the sorption reactions increased. This was attributed to the fact that the rate-limiting steps, for the binding of the studied metal(loid)s onto iron oxide, are generally considered to be dependent on the later stages of the sorption process related to diffusion mechanisms and not to the rate of mass transfer through the bulk liquid phase, which is what primarily is increased through application of the SpinChem® RBR technology.
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SINGH, OMPRAKASH. "IDENTIFICATION OF WEAK BUSES AND IMPROVING VOLTAGE PROFILE UNDER VARING LOAD CONDITIONS USING STATCOM IN IEEE-14 BUS POWER SYSTEM". Thesis, 2014. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19409.
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The whole world faces energy shortages, power scenario in present. There is a deficit
between energy demand and energy supplied. The per capita energy consumption indicates
the living standard of the society of the country and also it shows the development of the
country. Every country is trying to harness the energy obtained from natural resources and
maximize it, due to the limited resources of the fossil fuels. The major issue in these problem
is the voltage collapse of transmission system which is most suffered by the frequent
variations load. In this project, we focus on the detection and identification of weakest busses
under variation load. Voltage variation problem increase day-by-day with increasing load
demand power. Therefore the efficiency and power quality of power is become poor for
consumer service due to increasing load demand, voltage goes down. Thus the system
stability or voltage profile is poor at various buses in an interconnected power system under
varying load conditions (varying load 0 to 50% increasing). Hence the voltage magnitudes
and angles also change which are responsible for voltage instability which have major result
in blackout.
For the continuation power flow voltage magnitude, angle, real and reactive power should be
maintained so that voltage stability improved.
Finding the weakest buses during increasing load by Newton-Raphson method with
MATLAB programming and compare all results with original results with and without
STATCOM in an interconnected in IEEE 14 bus power system. As the results the voltage at
the buses goes below to specified voltage profile lower limit 0.98 p.u. during heavy load
conditions or voltage may exceed voltage profile upper limit 1.0 p.u. during light load
conditions, at there identified weakest buses allocation for the adjusted FACTS controllers to
improve voltage profile limit (0.98 p.u or 1.0 p.u ) of IEEE-14 bus power system to
maintained reactive power in IEEE-14 power system.
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Ahmed, Intesar. "Investigation of single and multiple faults under varying load conditions using multiple sensor types to improve condition monitoring of induction machines". 2008. http://hdl.handle.net/2440/58576.
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Condition monitoring involves taking measurements on an induction motor while it is operating in order to detect faults. For this purpose normally a single sensor type, for example current is used to detect broken rotor bar using fault frequency components only under the full-load condition or a limited number of load cases. The correlations among the different types of sensors and their ability to diagnose single and multiple faults over a wide range of loads have not been the focused in previous research. Furthermore, to detect different faults in machines using any fault frequency components, it is important to investigate the variability in its amplitude to other effects apart from fault severity and load. This area has also often been neglected in the literature on condition monitoring. The stator current and axial flux have been widely used as suitable sensors for detecting different faults i.e. broken rotor bar and eccentricity faults in motors. Apart from detecting the broken rotor bar faults in generalized form, the use of instantaneous power signal has often been neglected in the literature condition monitoring. This thesis aims to improve machine condition monitoring and includes accurate and reliable detection of single and multiple faults (faults in the presence of other faults) in induction machines over a wide range of loads of rated output by using current, flux and instantaneous power as the best diagnostic medium. The research presents the following specific tasks: A comprehensive real database from non–invasive sensor measurements, i.e. vibration measurements, axial flux, 3-phase voltage, 3-phase current and speed measurements of induction motor is obtained by using laboratory testing on a large set of identical motors with different single and multiple faults. Means for introducing these faults of varying severity have been developed for this study. The collected data from the studied machines has been analysed using a custom-written analysis programme to detect the severity of different faults in the machines. This helps to improve the accuracy and reliability in detecting of single and multiple faults in motors using fault frequency components from current, axial flux and instantaneous power spectra. This research emphasises the importance of instantaneous power as a medium of detecting different single and multiple faults in induction motor under varying load conditions. This enables the possibility of obtaining accurate and reliable diagnostic medium to detect different faults existing in machines, which is vital in providing a new direction for future studies into condition monitoring. Another feature of this report is to check the variability in healthy motors due to: test repeatability, difference between nominally identical motors, and differences between the phases of the same motor. This has been achieved by conducting extensive series of laboratory tests to examine fault frequency amplitudes versus fault severity, load, and other factors such as test repeatability and machine phases. The information about the variations in the amplitudes of the fault frequency components is used to check the accuracy and reliability of the experimental set-up, which is necessary for the practical application of the results to reliably detect the different faults in the machines reliably. Finally, this study also considers the detection of eccentricity faults using fault frequency amplitudes as a function of average eccentricity, instead of as a function of load under different levels of loading. This has not been reported in previous studies.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1298314
Thesis (Ph.D.)-- University of Adelaide, School of Electrical and Electronic Engineering, 2008
Książki na temat "VARING LOAD CONDITIONS"
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Wyatt, Laura A., i Michael Doherty. Morphological aspects of pathology. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199668847.003.0003.
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Osteoarthritis (OA) is the commonest condition to affect synovial joints, but although any synovial joint can be affected, most studies of pathology relate to large joints (knees and hips). OA involves the whole joint and pathological alterations typically occur in all joint tissues. Established OA is characterized by a mixture of tissue loss and new tissue production resulting in focal loss of articular hyaline cartilage together with bone remodelling and osteophyte formation. Articular cartilage may show increased thickness in the earliest stages of OA with increased numbers of hypertrophic chondrocytes, followed by progressive decline in matrix components, thickness, and chondrocyte number. Surface fibrillation and vertical clefts become evident in mid- to end-stage OA and eventual complete loss of cartilage can occur, predominantly in maximum load-bearing regions, with subsequent eburnation and furrowing of bone. Bone remodelling may lead to alteration of bone shape and variable trabecular thickness in subchondral bone, whilst subchondral microfractures may result in localized osteonecrosis, fibrosis, and ‘cysts’. Endochondral ossification of new fibrocartilage produced predominantly at the joint margin produces characteristic bony osteophytes. The synovium shows areas of hyperplasia with varying amounts of lymphocyte aggregates and inclusion of osteochondral ‘loose’ bodies, and the outer fibrous capsule thickens to help stabilize the compromised joint. Synovial fluid increases in volume but decreases in viscosity. Periarticular changes include type II muscle atrophy and enthesophytes.
Części książek na temat "VARING LOAD CONDITIONS"
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Bokhari, Shahid H. "Varying Load Conditions". W The Kluwer International Series in Engineering and Computer Science, 71–93. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4613-2003-6_5.
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Loukopoulos, Panagiotis, George Zolkiewski, Ian Bennett, Suresh Sampath, Pericles Pilidis, Fang Duan i David Mba. "Reciprocating Compressor Valve Leakage Detection Under Varying Load Conditions". W Lecture Notes in Mechanical Engineering, 405–14. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95711-1_40.
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Fahrnberger, Günter. "Reliable Condition Monitoring of Telecommunication Services with Time-Varying Load Characteristic". W Distributed Computing and Internet Technology, 173–88. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-72344-0_14.
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Randall, Robert B., Nader Sawalhi i Michael Coats. "Separation of Gear and Bearing Fault Signals from a Wind Turbine Transmission under Varying Speed and Load". W Condition Monitoring of Machinery in Non-Stationary Operations, 3–12. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-28768-8_1.
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Lao, Keng-Weng, Man-Chung Wong i NingYi Dai. "Various Design Techniques of Co-phase Traction Power with Railway HPQC for Varying Load". W Co-phase Traction Power Supply with Railway Hybrid Power Quality Conditioner, 113–84. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0438-5_4.
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Zhang, Jun, Jian Wang, Xike Li, Ligang Yao i Xianzeng Liu. "Lateral-Torsional-Coupled Model Based Dynamic Analyses of Spur Gears Under Time-Varying External Load Conditions with Surface Wear". W Nonlinear Systems and Complexity, 107–33. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94301-1_5.
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Sharif Khodaei, Zahra, i Stephen Grigg. "Aerospace Requirements". W Structural Health Monitoring Damage Detection Systems for Aerospace, 73–85. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-72192-3_4.
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AbstractThis chapter covers the overview of requirements arising in the aerospace industry for operating a structural health monitoring (SHM) system. The requirements are based on existing standards and guidelines and include both requirements on the physical components of the system (such as sensors, data acquisition systems and connectors) and their functional requirements (such as reliability, confidence measure and probability of detection). Emphasis has been given to on-board and ground-based components because they have different functionality requirements. An important factor in the reliability of the system is the effect of the environment and operational loads on the reliability of the diagnosis and, consequently, prognosis. The recommended guidelines for testing the reliability of the system under varying operational conditions are presented. This chapter is then finalized by reporting on methodologies for optimal sensor number and placement, based on different sensor technologies and different optimization algorithms.
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Barklage, Alexander, i Rolf Radespiel. "Interaction of Wake and Propulsive Jet Flow of a Generic Space Launcher". W Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 129–43. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53847-7_8.
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Abstract This work investigates the interaction of the afterbody flow with the propulsive jet flow on a generic space launcher equipped with two alternative nozzle concepts and different afterbody geometries. The flow phenomena are characterized by experimental measurements and numerical URANS and LES simulations. Investigations concern a configuration with a conventional truncated ideal contour nozzle and a configuration with an unconventional dual-bell nozzle. In order to attenuate the dynamic loads on the nozzle fairing, passive flow control devices at the base of the launcher main body are investigated on the configuration with TIC nozzle. The nozzle Reynolds number and the afterbody geometry are varied for the configuration with dual-bell nozzle. The results for integrated nozzles show a shift of the nozzle pressure ratio for transition from sea-level to altitude mode to significant lower levels. The afterbody geometry is varied including a reattaching and non-reattaching outer flow on the nozzle fairing. Investigations are performed at supersonic outer flow conditions with a Mach number of $$Ma_\infty =3$$. It turns out, that a reattachment of the outer flow on the nozzle fairing leads to an unstable nozzle operation.
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Mado, Ismit. "Identification of Predicted Load Cluster Pattern Power Generation Parameters Based on Descriptive Time Series Analysis". W Model-Based Control Engineering - Recent Design and Implementations for Varied Applications. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.99126.
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This chapter describes the process of identifying a power generation system. This is important because in principle the system parameters as a whole are not linear and uncertain. For this reason, it is necessary to carry out an identification process using an experimental approach that is able to represent the system as a whole. The technique used in this identification process is Prediction Error Minimization (PEM) as a tool available in Matlab. Identification is done by simulating changes in the value of frequency, voltage and electrical power due to changes in load. The change in load over time is a characteristic of the time series pattern. Through descriptive analytic approach, the cluster load is patterned for each load operating condition. Through load clusters, the identification results of power generation systems are obtained based on their operating conditions. This chapter presents validated parameter estimates for each change in instantaneous load conditions. The simulation results obtained better performance between the actual output and the identification model, namely the calculation of the Intergal Absolute Error (IAE), with MAPE for the average frequency value of 73.95 percent, nominal voltage of 0.23 percent, and electric power of 23.46 percent.
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Cruz, S. M. A., i A. J. Marques Cardoso. "Discriminating Between Rotor Asymmetries and Time-Varying Loads in Three-Phase Induction Motors". W Condition Monitoring and Diagnostic Engineering Management, 319–27. Elsevier, 2001. http://dx.doi.org/10.1016/b978-008044036-1/50037-8.
Pełny tekst źródłaStreszczenia konferencji na temat "VARING LOAD CONDITIONS"
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Böttcher, Jonas, Jaroslaw Szwedowicz, Martin Jahn i Marcus Neubauer. "Shape Memory Actuator System for Passive Cooling Air Adjustment in Mechanical Design". W ASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/smasis2013-3040.
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Passive control of cooling processes is in designs best interest. Coolant medium flow to hot components must be kept at minimum acceptable level from lifting perspective to achieve maximum process efficiency. Required cooling of the hot components depends directly on engine power setting, which in general requires a relative complex system for monitoring critical parameters and adjusting coolant’s amount with engine load. Concerning the operation reliability, pseudoplastic shape memory alloys offer a high simplicity in the design of adjustment mechanisms with large operating displacements. As the shape memory effect is induced by temperature changes, the behavior of shape memory actuators and therefore the coolant’s amount can be adjusted to the load conditions of the engine by using appropriate shape memory materials. In this paper an actuator based on a shape memory membrane using the extrinsic two-way effect is presented to vary the cross-sectional area of a cooling air channel with respect to the engine operation. The reset of the mechanism after one temperature cycle of heating and cooling is realized by using a leaf spring element, which is in varing mechanical contact with the shape memory membrane depending on the hysteresis of the entire system. Maximum displacements of the system are attained for spring forces between the force generated by the shape memory membrane in the martensitic and austenitic state. Thus, the system mechanism exhibits two non-linearities of pseudoplastic shape memory characteristic and contact mechanics with friction. For this purpose experimental investigations were carried out to acquire the fundamental force displacement behavior of the shape memory membrane to design the optimal shape of the leaf spring element. The forces required to deform the shape memory membrane in the martensitic and austenitic state were measured with respect to the membranes displacement using a load cell and a linear variable differential transformer. The displacements of the membrane were introduced using a linear bearing system. The calculations for the design of an optimal leaf spring and especially its initial shape were carried out using a discrete multi body system consisting of beam elements and torsional springs. The leaf spring with the calculated optimal shape was fabricated and incorporated into the system. The displacement behavior of the system during heating and cooling was measured using an optical distance sensor. For the analyzed temperature range up to 100 °C, the paper describes the methodological appropriacy and relevance towards the application domain for evaluated temperatures.
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Chakraborty, Monisha, i Debanjan Parbat. "Fractal analysis of sEMG signal under varying load conditions". W 2016 2nd International Conference on Control, Instrumentation, Energy & Communication (CIEC). IEEE, 2016. http://dx.doi.org/10.1109/ciec.2016.7513833.
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Cheng, Chong, Hanfei Mei, Victor Giurgiutiu, Shenfang Yuan, Fang Fang i Robin James. "Simulation of guided wave under varying temperature and load conditions". W Health Monitoring of Structural and Biological Systems IX, redaktorzy Paul Fromme i Zhongqing Su. SPIE, 2020. http://dx.doi.org/10.1117/12.2559702.
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Ramakrishnan, Kishore Ranganath, Shoaib Ahmed, Srinath Ekkad, Federico Liberatore i Yin-Hsiang Ho. "Characterization of Transient Wall Heat Load for a Low NOx Lean Premixed Swirl Stabilized Can Combustor Under Reacting Conditions". W ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14429.
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Abstract Modern combustor design optimization is contingent on the accurate characterization of the combustor flame side heat loads. Knowledge of regions of high and low heat loads on the liner wall helps designers optimize the cooling designs. The present work focuses on the experimental measurement of the transient heat load along a fused silica (quartz) optical can combustor under reacting conditions for a swirl stabilized premixed methane-air flame. Equivalence ratio was varied from 0.55 to 0.65. Reynolds number based on combustor diameter was varied from 12500 to 18000, where the preheated air temperature was approximately 373 K. The percentage of pilot fuel was varied from 6% to 10% of the main fuel flow rate. Inner and outer walls of the liner were painted with a high temperature flat black paint with an azimuthal offset to aid in infrared measurement of the wall temperature using an infrared camera. Particle Image Velocimetry (PIV) was employed to visualize the flow field for various reacting conditions studied in this work. Based on the heat transfer study, a detailed report of transient heat load along the length of the liner wall for varying reacting conditions has been presented here. The location of impingement of the flame onto the liner and velocity of the flow field were obtained from PIV measurements. Wall heat load at various planes along the length of the liner have been presented. Repeatability of this transient experiment was within 10% between eight different runs for various locations along the length of the liner, except for the region close to flame impingement zone. In the impingement zone, liner heat load varied by about 25% between different runs. It was observed that the change in heat load upstream of the location of impingement on the liner was insignificant with change in pilot ratio as the system tends towards a steady state, contrary to the regions downstream. Higher Reynolds number and equivalence ratios increased the heat load on the liner as expected.
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Ganesh, V., i Chidambaram Subramanian. "Variable Braking Force Using Intelligent Twin Calipers". W ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86594.
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Automobile Braking System is one of the most important sub systems of the vehicle. It is the primary safety system since the stopping of the vehicle is majorly dependent on this system. This system utilises the frictional force between the tire and the road to stop the vehicle. The braking force required by the vehicle is governed by two factors. One of them is the coefficient of friction between the tire and the road surface, the other one is the load on the vehicle. Thus, required braking force to halt the vehicle with the minimum possible stopping distance varies with the load in the vehicle. If the applied braking force is greater than the required brake force, wheel gets locked which results in increased stopping distance. In order to prevent the wheel lock at low load conditions, a variable braking force system is developed. In Motorcycles, the pillion load majorly contributes to the overall weight. Thus, the amount of braking force required to stop with minimum stopping distance also varies drastically with respect to pillion load condition. Hence, the amount of braking force developed between the road surface and the tire is varied in the variable braking force system. In this project, variable brake force system is achieved by varying the effective disc radius. The maximum braking force developed between the ground and the tire is controlled based on the pillion load on the motor cycle, if friction is present between the tire and the ground. Two calipers are mounted on the brake disc of which one is fixed at a constant distance (constant effective disc radius – 67mm) and the other is movable depending on the load on the motorcycle. The movable caliper slides upwards and downwards such that the effective disc radius is varied based on the pillion load. Using a load cell, the load of the vehicle is determined. A microcontroller is programmed to move the caliper with the help of a stepper motor based on the load on the motorcycle. This way, the effective disc radius is varied for various loads on the motorcycle.
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Von Hagel, Kayla, Shreyas Joglekar, Mark Pankow i Scott M. Ferguson. "Exploring Composite Panels Using Multi-Objective Optimization and Varying Load Conditions". W 15th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2014. http://dx.doi.org/10.2514/6.2014-3161.
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Mutama, Kuda R., i Norm Duperron. "Load Cycling of a 242 MW Coal Fired Steam Turbine Plant Designed for Base Load Operations". W ASME 2010 Power Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/power2010-27306.
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The TS Power Plant (TSPP) is a 242 MW gross coal fired power plant designed to operate base loaded. The plant is new and began commercial operations in June 2008. Due to high volumes of snow fall in the northwest the availability of low cost hydropower in 2009 reduced power demand from TSPP and other coal based generating stations. Moreover in 2009 natural gas prices fell to the lowest point in years making energy from newer more efficient combined cycle power plants very favorable. This paper examines the performance of TSPP under varying load output conditions with regard to key plant equipment such as the boiler, steam turbine generator and air quality systems for the flue gas. The plant was being operated from minimum load without firing oil (80 NMW) to sometimes full load conditions (218 NMW). Load changes were experienced on an hour to hour basis for several months. Load changes varied from 40 NMW increasing to 60 NMW decreasing during the 20 minute load change window during the hour. The boiler has three coal pulverizers. The boiler can achieve full load operations with two pulverizers, however all three pulverizers are ran at times for reliability. At loads less than 140 NMW the plant can operate one pulverizer but operations at loads lower than 80 NMW requires oil burners for flame stabilization. Transition points from one pulverizer to two pulverizer operations also cause challenges during load changes. However examining plant operating data over the load ranges has shown that TSPP has performed very well despite the varying load schedule. The plant heat rate is a good indicator as to how well the plant has performed. The heat rate has varied from under 10,000 Btu/kwhr at low loads (< 100 MW net) to around 9,400 Btu/kWhr at higher loads (> 175 MWnet). A summary of plant boiler and turbine data under various loads is also presented in this paper as well as balance of plant equipment.
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Draycott, Samuel, Jeffrey Steynor, Anup Nambiar, Brian Sellar i Vengatesan Venugopal. "Tidal Turbine Load Variability in Following and Opposing Irregular Wave Conditions". W ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18701.
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Abstract Waves induce large loads on tidal turbines, yet the effect of irregular waves, particularly those which oppose the current direction, have received little attention. Here we experimentally assess the loading resulting from 24 irregular combined wave-current cases, statistically presenting the load variability acting on a 1:15 scale tidal turbine. Comparisons are made between following and opposing conditions of equivalent wave parameters, and the effect of varying frequency and amplitude is assessed. Example load distributions are also shown, along with streamwise variation of significant wave height around the turbine. It is concluded that both opposing and following conditions must be assessed to effectively de-risk tidal turbine design: large differences are observed both in terms of the nature & magnitude of the resulting loads and the wave interaction with the surrounding flow field.
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Ahmed, K. J., Nur Izzati Zainal, Sabihul Hafiz, R. Mizan, Sheroz Khan i Anis Nurashikin Bt Nordin. "Wireless Power Transmission - exploring source to load inductive link under resonance and varying load condition". W 2016 IEEE Student Conference on Research and Development (SCOReD). IEEE, 2016. http://dx.doi.org/10.1109/scored.2016.7810045.
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Eskelinen, Petri, Ilmari Repo, Kari Aho i Frans Laakso. "On HSUPA Open Loop Switched Antenna Transmit Diversity Performance in Varying Load Conditions". W 2011 IEEE Vehicular Technology Conference (VTC 2011-Spring). IEEE, 2011. http://dx.doi.org/10.1109/vetecs.2011.5956588.
Pełny tekst źródłaRaporty organizacyjne na temat "VARING LOAD CONDITIONS"
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Fowler. L51754 Field Application of Electronic Gas Admission with Cylinder Pressure Feedback for LB Engines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), czerwiec 1996. http://dx.doi.org/10.55274/r0010363.
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�The purpose of this project was to evaluate the performance of electronic fuel gas admission valves and effects of continuous automatic cylinder balancing of large bore natural gas engines under actual field conditions. These goals have already been met under laboratory conditions at the Colorado State University Engines and Energy Conversion Laboratory in Fort Collins. The specific project objectives were to:1. Extend the feasibility of electronic fuel gas admission valves where gas valve timing and duration are varied to optimize fuel control and charge mixing from the laboratory environment to actual field applications. 2. Extend the feasibility of closed loop control using in-cylinder pressure sensors to achieve continuous, automatic power cylinder balancing from the laboratory environment to actual field applications. 3. Repeat the benefits of automatic continuous cylinder balancing shown in the laboratory testing under actual field conditions (i.e. fuel savings, improved cylinder misfire rates, improved emissions levels). In order to accomplish these objectives, the Woodward Governor Company AutoBalance TM 5000 control system was installed and tested at four host sites. Although the specific test plan differed slightly for the four host sites, the focus of the test program was consistent. The primary objective was to evaluate the effects of engine balance and the performance of the control system by testing a matrix of varying engine loads and speeds. Load and speed are the two primary control parameters affecting engine balance. Other tests were conducted to determine the effects of the electronic gas admission valve (EGAV) configuration (i.e. start of admission, end of admission, and duration).
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Wilmont, Martyn, Greg Van Boven i Tom Jack. GRI-96-0452_1 Stress Corrosion Cracking Under Field Simulated Conditions I. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), listopad 1997. http://dx.doi.org/10.55274/r0011963.
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Electrochemical measurements have been performed on polished and mill scaled steel samples. The solutions investigated have included carbonate bicarbonate mixtures of varying pH as well as solutions of neutral pH such as NS4. Results indicate that the mechanism of corrosion associated with the carbonate bicarbonate environments involves passive film formation. No such passivation is observed for solutions associated with neutral pH SCC. Electrochemical corrosion rates measured on polished steel specimens exposed to NS4 solutions in the pH range 5 to 6.8 were in the region of 5 x 10e-1 to 1 x 10e-2 mm/s. However, rates obtained on mill scaled surfaces went much lower and in the region of 5 x 10e-10 mm/s. Field determined crack propagation rates are estimated to be in the region of 2 x 10e-8 mm/s. Whilst the laboratory determined corrosion rates are lower than the field propagation rate it should be remembered that the laboratory rates were obtained on unstressed specimens. The application of load would be expected to increase the corrosion rate and may indicate that stress focused dissolution process may be sufficient to explain the propagation of neutral pH stress corrosion cracks. However, as hydrogen evolution is the most likely cathodic reaction involved in the mechanism of neutral pH SCC the role of hydrogen in the crack propagation mechanism may also be important.
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Schiller, Brandon, Tara Hutchinson i Kelly Cobeen. Cripple Wall Small-Component - Test Program: Comparisons (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/lohh5109.
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This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER) and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4 (WG4): Testing, whose central focus was to experimentally investigate the seismic performance of retrofit and existing cripple walls. Amongst the body of reports from WG4, in the present report, a suite of four small cripple wall test phases, in total 28 specimens, are cross compared with varied exterior finishes, namely stucco (wet) and non-stucco (dry) exterior finishes. Details representative of era specific construction, specifically the most vulnerable pre-1960s construction are of predominant focus in the present effort. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load onto cripple walls of 12 ft in length and 2 ft or 6 ft in height. All specimens in this report were constructed with the same boundary conditions and tested with the same vertical load. Parameters addressed in this report include: wet exterior finishes (stucco over framing, stucco over horizontal lumber sheathing, and stucco over diagonal lumber sheathing); and dry exterior finishes (horizontal siding, horizontal siding over diagonal sheathing, and T1-11 wood structural panels) with attention towards cripple wall height and the retrofit condition. The present report provides only a brief overview of the test program and setup; whereas a series of three prior reports present results of test groupings nominally by exterior finish type (wet versus dry). As such, herein the focus is to cross compare key measurements and observations of the in-plane seismic behavior of all 28 specimens.
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Author, Unknown. PR-203-027-R01 Evaluation of Screen Testing Program for J-Lay Connections. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), marzec 1992. http://dx.doi.org/10.55274/r0012125.
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This report discusses the results of a testing program designed to simulate the operational conditions imposed on a J-lay installed, 13%" subsea pipeline assembled with mechanical connections. The program objective was to gain an understanding of the long-term sealing integrity of various mechanical connections. The connections were subjected to combinations of cyclic internal pressure, cyclic temperature, axial compression, and reverse torsion. The testing results show that the mechanically interlocked Reflange C-Con II connection and two premium threaded connections, the Hunting Fox and Sumitomo Varn Ace, when assembled utilizing suitable bonding agents, successfully resisted the imposed loads of this testing program. In addition, the selection of a proper bonding agent or adhesive to prevent reverse torque back out proved to be important as several of these agents were unreliable in preventing back out failures. The testing conditions applied to the mechanical connections in this test program are believed to be conservative, exceeding the maximum that in-service, J-lay installed pipelines are likely to experience. Therefore, this test program may be used to select a pipeline connection for this duty.
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Mohr, H. O. PR-209-9217-R01 Mechanical Connections for J-lay. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), lipiec 1994. http://dx.doi.org/10.55274/r0012126.
Pełny tekst źródłaStreszczenie:
This report discusses the results of a testing program designed to simulate the operational conditions imposed on a J-lay installed, 13%" subsea pipeline assembled with mechanical connections. The program objective was to gain an understanding of the long-term sealing integrity of various mechanical connections. The connections were subjected to combinations of cyclic internal pressure, cyclic temperature, axial compression, and reverse torsion. The testing results show that the mechanically interlocked Reflange C-Con II connection and two premium threaded connections, the Hunting Fox and Sumitomo Varn Ace, when assembled utilizing suitable bonding agents, successfully resisted the imposed loads of this testing program. In addition, the selection of a proper bonding agent or adhesive to prevent reverse torque back out proved to be important as several of these agents were unreliable in preventing back out failures. The testing conditions applied to the mechanical connections in this test program are believed to be conservative, exceeding the maximum that in-service, J-lay installed pipelines are likely to experience. Therefore, this test program may be used to select a pipeline connection for this duty.
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Cobeen, Kelly, Vahid Mahdavifar, Tara Hutchinson, Brandon Schiller, David Welch, Grace Kang i Yousef Bozorgnia. Large-Component Seismic Testing for Existing and Retrofitted Single-Family Wood-Frame Dwellings (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/hxyx5257.
Pełny tekst źródłaStreszczenie:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. Quantifying the difference of seismic performance of un-retrofitted and retrofitted single-family wood-frame houses has become increasingly important in California due to the high seismicity of the state. Inadequate lateral bracing of cripple walls and inadequate sill bolting are the primary reasons for damage to residential homes, even in the event of moderate earthquakes. Physical testing tasks were conducted by Working Group 4 (WG4), with testing carried out at the University of California San Diego (UCSD) and University of California Berkeley (UCB). The primary objectives of the testing were as follows: (1) development of descriptions of load-deflection behavior of components and connections for use by Working Group 5 in development of numerical modeling; and (2) collection of descriptions of damage at varying levels of peak transient drift for use by Working Group 6 in development of fragility functions. Both UCSD and UCB testing included companion specimens tested with and without retrofit. This report documents the portions of the WG4 testing conducted at UCB: two large-component cripple wall tests (Tests AL-1 and AL-2), one test of cripple wall load-path connections (Test B-1), and two tests of dwelling superstructure construction (Tests C-1 and C-2). Included in this report are details of specimen design and construction, instrumentation, loading protocols, test data, testing observations, discussion, and conclusions.
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Schiller, Brandon, Tara Hutchinson i Kelly Cobeen. Comparison of the Response of Small- and Large-Component Cripple Wall Specimens Tested under Simulated Seismic Loading (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/iyca1674.
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This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4: Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. Two testing programs were conducted; the University of California, Berkeley (UC Berkeley) focused on large-component tests; and the University of California San Diego (UC San Diego) focused on small-component tests. The primary objectives of the tests were to develop descriptions of the load-deflection behavior of components and connections for use by Working Group 5 in developing numerical models and collect descriptions of damage at varying levels of drift for use by Working Group 6 in developing fragility functions. This report considers two large-component cripple wall tests performed at UC Berkeley and several small-component tests performed at UC San Diego that resembled the testing details of the large-component tests. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load on cripple wall assemblies. The details of the tests are representative of era-specific construction, specifically the most vulnerable pre-1945 construction. All cripple walls tested were 2 ft high and finished with stucco over horizontal lumber sheathing. Specimens were tested in both the retrofitted and unretrofitted condition. The large-component tests were constructed as three-dimensional components (with a 20-ft 4-ft floor plan) and included the cripple wall and a single-story superstructure above. The small-component tests were constructed as 12-ft-long two-dimensional components and included only the cripple wall. The pairing of small- and large-component tests was considered to make a direct comparison to determine the following: (1) how closely small-component specimen response could emulate the response of the large-component specimens; and (2) what boundary conditions in the small-component specimens led to the best match the response of the large-component specimens. The answers to these questions are intended to help identify best practices for the future design of cripple walls in residential housing, with particular interest in: (1) supporting the realistic design of small-component specimens that may capture the response large-component specimen response; and (2) to qualitatively determine where the small-component tests fall in the range of lower- to upper-bound estimation of strength and deformation capacity for the purposes of numerical modelling. Through these comparisons, the experiments will ultimately advance numerical modeling tools, which will in turn help generate seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings. To this end, details of the test specimens, measured as well as physical observations, and comparisons between the two test programs are summarized in this report.
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Kerber, Steve. Study of the Effectiveness of Fire Service Vertical Ventilation and Suppression Tactics in Single Family Homes. UL Firefighter Safety Research Institute, czerwiec 2013. http://dx.doi.org/10.54206/102376/iwzc6477.
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Under the United States Department of Homeland Security (DHS) Assistance to Firefighter Grant Program, Underwriters Laboratories examined fire service ventilation and suppression practices as well as the impact of changes in modern house geometries. There has been a steady change in the residential fire environment over the past several decades. These changes include larger homes, more open floor plans and volumes, and increased synthetic fuel loads. This investigation examined the influence of these changes to the fire behavior and subsequent impact on firefighter tactics relative to horizontal and vertical ventilation and suppression. It is anticipated that the results of this investigation will be incorporated into improved firefighting tactics and decision making to reduce firefighter injuries and fatalities. Vertical ventilation has been used successfully but also resulted in firefighter fatalities in the past, as it is not easily coordinated with suppression and other fire ground tasks such as horizontal ventilation. It is not straightforward for firefighters to train on the effects of vertical ventilation since fire service training structures and props do not allow for ventilation-limited fire conditions with representative fuel loads and floor plans that will be encountered on the fire ground. Thus, guidance on the effectiveness of vertical ventilation comes from experience gained during real incidents, but under many different fire ground conditions. This has made it difficult to develop comprehensive guidance on the coordination of vertical ventilation with other firefighter tactics, and how these tactics may influence the fire dynamics in the burning home. The purpose of this study was to improve the understanding of the fire dynamics associated with the use of vertical ventilation so that it may be more effectively deployed on the fire ground. Two houses were constructed in the large fire facility of Underwriters Laboratories in Northbrook, IL. The first house was a one-story house (1200 ft, three bedrooms, one bathroom) with a total of 8 rooms. The second house was a two-story house (3200 ft, four bedrooms, two and a half bathrooms) with a total of 12 rooms. The second house featured a modern open floor plan, two-story great room and open foyer. A total of seventeen experiments were conducted varying the ventilation locations and the number of ventilation openings. Ventilation scenarios included ventilating the front door and a window near the seat of the fire (with modern and legacy furnishings) to link to the previous research on horizontal ventilation, opening the front door and ventilating over the fire and remote from the fire. Additional experiments examined controlling the front door, making different sized ventilation holes in the roof and the impact of exterior hose streams. The results from the experiments led to identification of tactical considerations for the fire service to integrate into their education and fire ground strategies and tactics where applicable.
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Maupin, Julie, i Dr Michael Mamoun. DTPH56-06-T-0004 Plastic Pipe Failure, Risk, and Threat Analysis. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), marzec 2006. http://dx.doi.org/10.55274/r0012119.
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Reports, publications, papers, and databases were reviewed to better define risks and threats to plastic gas distribution piping. Failure modes were described for plastic PE piping with the most significant being slow crack growth (SCG). Short-term mechanical tests such as tensile, quick burst, melt index, and density tests did not show a correlation with a material's susceptibility to SCG failure. The bend-back test was able to visually identify 1971 low-ductile inner wall materials. PENT test failure times were reported for materials manufactured during the period1972-1985. The PENT test did not show correlations with the material's susceptibility to SCG failure for these materials. Life expectancy was determined to be a key measure of the susceptibility of PE gas pipe materials to SCG field failures. Long-term hydrostatic stress-rupture data combined with the Rate Process Method or with the Bi-Directional Shift Functions predicted the remaining life expectancy of several PE materials at 60�F average field temperature under varying loading conditions. Data showed rock impingement loads and pipe squeeze-offs can result in the greatest reduction in remaining life expectancy. Lower operating field temperatures and pressures significantly increased the predicted remaining life expectancy of PE materials. Fifty-five PE pipe samples that failed in field service were examined in the laboratory to identify the root cause of the failures. Eight of the samples underwent in-depth analysis, which included density and melts index tests and differential scanning calorimetry, infrared spectroscopy, and microscopic examination of the fracture surfaces. The samples were combined with another set of additional data resulting in 45 material, 36 procedural, 12 quality control, and 7 miscellaneous failures. A separate categorization method attributed a total of 321 failures to their respective pipe/component, with most occurring at joints. RCP in large diameter PE materials was investigated through laboratory testing. Critical pressure was determined for 6 pipe materials. The critical temperature was determined for 3 materials.
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Some complex approaches to training micro-cycles formation among cadetsweightlifters taking into account biotypes. Ilyas N. Ibragimov, Zinaida M. Kuznetsova, Ilsiyar Sh. Mutaeva, marzec 2021. http://dx.doi.org/10.14526/2070-4798-2021-16-1-39-46.
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Training cadets-weightlifters at all stages has a multipurpose orientation, that is why it is important to define and plan a rational combination of the training means use. Distribution of such micro structures in the cycle of training, as the days, months of training, provides effective volume, intensity and other values of physical load distribution. The structure of training cadets-weightlifters is based on taking into account the regularities and principles of sports training as the condition for physical readiness and working capacity increase. Any power oriented sports demands components characteristics in the structure of micro cycles. We consider the methodology of the training lessons organization by the example of the micro cycle of training taking into account bioenergetic profile of cadets-weightlifters. We revealed the necessity to distribute the macro cycle to structural components as the condition for the effectiveness of different variants of the training effects distribution. Materials and methods. We analyzed the range of training lessons among cadets-weightlifters in order to create the variants of gradual training problems solution according to the kinds of training. We analyzed training programs of cadets taking into consideration the level of readiness and their bioenergetic profiles. We created the content of the training work in the micro cycle of the preparatory period for cadets-weightlifters with different bioenergetic profiles. The main material of the research includes the ratio of the training effects volume in one micro cycle taking into account cadets’ bioenergetic profile. Cadets-weightlifters from Tyumen Higher Military-Engineering Command College (military Institute) took part in the research (Tyumen, Russia). Results. We created the content of the training work by the example of one micro cycle for cadets-weightlifters taking into account bioenergetic profile. The created variant of the training loads structure includes the main means of training taking into account the kind of training. Realization orientation in five regimens of work fulfillment with the effectiveness estimation of a total load within one lesson and a week in general is estimated according to a point system. Conclusion. The created variant of a micro cycle considers kinds of training realization taking into account the percentage of the ratio. Taking into account bioenergetic profiles helps to discuss strong and weak sides of muscle activity energy supply mechanisms. We consider the ability to fulfill a long-term aerobic load among the representatives of the 1st and the 2nd bioenergetic profiles. The representatives of the 3rd and the 4th biotype are inclined to fulfill the mixed load. The representatives of the 5th biotype are characterized by higher degree of anaerobic abilities demonstration. The technology of planning the means taking into account the regimens of work realization with point system helps to increase physical working capacity and rehabilitation processes in cadets’ organisms.