Academic literature on the topic 'Dynamic processes during acceleration'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Dynamic processes during acceleration.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Dynamic processes during acceleration"
1
Pomante, A., L. P. J. Selen, and W. P. Medendorp. "Perception of the dynamic visual vertical during sinusoidal linear motion." Journal of Neurophysiology 118, no. 4 (October 1, 2017): 2499–506. http://dx.doi.org/10.1152/jn.00439.2017.
Full textAbstract:
The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical—as a proxy for the tilt percept—during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s2peak acceleration, 80 cm displacement). While subjects ( n=10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model’s prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical.NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the disambiguation of linear acceleration and spatial orientation. We discuss the dynamics of these illusory percepts in terms of a dynamic Bayesian model that combines uncertainty in the vestibular signals with priors based on the natural statistics of head motion.
2
Zheng, Jingjing, Abuduwaili Abulikemu, Yan Wang, Meini Kong, and Yiwei Liu. "Convection Initiation Associated with the Merger of an Immature Sea-Breeze Front and a Gust Front in Bohai Bay Region, North China: A Case Study." Atmosphere 13, no. 5 (May 6, 2022): 750. http://dx.doi.org/10.3390/atmos13050750.
Full textAbstract:
The mechanism for convection initiation (CI) associated with the merger of an immature sea-breeze front (SBF) and gust front (GF) that occurred in North China on 31 July 2010 was investigated based on both observations and Weather Research and Forecasting (WRF) model simulation. The results show that many CIs occurred continuously in the merging area, and eventually resulted in an intense mesoscale convective system (MCS). The WRF simulation captured the general features of the SBF, GF, their merger processes and associated CIs, as well as the resulting MCS. Quantitative Lagrangian vertical momentum budgets, in which the vertical acceleration was decomposed into dynamic and buoyant components, were conducted along the backward trajectories of air parcels within a convective cell initiated in the merger processes. It was found that both of the dynamic and buoyant accelerations played important roles for the CI. The buoyant acceleration was dominated by the warming due to the latent heat release within the convective cell. Further decomposition of the dynamic acceleration showed the vertical twisting and extension contributed significantly to the dynamic acceleration, while the horizontal curvature was rather small. The vertical twisting was generated due to the vertical shear of horizontal wind, while the extension indicated convergences owing to a mid-level blocking convergence effect and squeezing, and (or) merging of the convergent leading edges of both fronts during their merger processes. The weak convergent leading edge of the immature SBF played an important role for the formation of the convergences.
3
Carey, Jonathan M., Chris I. Massey, Barbara Lyndsell, and David N. Petley. "Displacement mechanisms of slow-moving landslides in response to changes in porewater pressure and dynamic stress." Earth Surface Dynamics 7, no. 3 (August 6, 2019): 707–22. http://dx.doi.org/10.5194/esurf-7-707-2019.
Full textAbstract:
Abstract. Although slow-moving landslides represent a substantial hazard, their detailed mechanisms are still comparatively poorly understood. We have conducted a suite of innovative laboratory experiments using novel equipment to simulate a range of porewater pressure and dynamic stress scenarios on samples collected from a slow-moving landslide complex in New Zealand. We have sought to understand how changes in porewater pressure and ground acceleration during earthquakes influence the movement patterns of slow-moving landslides. Our experiments show that during periods of elevated porewater pressure, displacement rates are influenced by two components: first an absolute stress state component (normal effective stress state) and second a transient stress state component (the rate of change of normal effective stress). During dynamic shear cycles, displacement rates are controlled by the extent to which the forces operating at the shear surface exceed the stress state at the yield acceleration point. The results indicate that during strong earthquake accelerations, strain will increase rapidly with relatively minor increases in the out-of-balance forces. Similar behaviour is seen for the generation of movement through increased porewater pressures. Our results show how the mechanisms of shear zone deformation control the movement patterns of large slow-moving translational landslides, and how they may be mobilised by strong earthquakes and significant rain events.
4
Oh, Ji-Hyun, Xianan Jiang, Duane E. Waliser, Mitchell W. Moncrieff, Richard H. Johnson, and Paul Ciesielski. "A Momentum Budget Analysis of Westerly Wind Events Associated with the Madden–Julian Oscillation during DYNAMO." Journal of the Atmospheric Sciences 72, no. 10 (October 1, 2015): 3780–99. http://dx.doi.org/10.1175/jas-d-15-0044.1.
Full textAbstract:
Abstract The Dynamics of the Madden–Julian Oscillation (DYNAMO) field campaign was conducted over the Indian Ocean (IO) from October 2011 to February 2012 to investigate the initiation of the Madden–Julian oscillation (MJO). Three MJOs accompanying westerly wind events (WWEs) occurred in late October, late November, and late December 2011. Momentum budget analysis is conducted to understand the contributions of the dynamical processes involved in the wind evolution associated with the MJO over the IO during DYNAMO using European Centre for Medium-Range Weather Forecasts analysis. This analysis shows that westerly acceleration at lower levels associated with the MJO active phase generally appears to be maintained by the pressure gradient force (PGF), which could be partly canceled by meridional advection of the zonal wind. Westerly acceleration in the midtroposphere tends to be mostly attributable to vertical advection. The results herein imply that there is no simple linear dynamic model that can capture the WWEs associated with the MJO and that nonlinear processes have to be considered. In addition, the MJO in November (MJO2), accompanied by two WWEs (WWE1 and WWE2) spaced a few days apart, is diagnosed. Unlike other WWEs during DYNAMO, horizontal advection is more responsible for the westerly acceleration in the lower troposphere for WWE2 than the PGF. Interactions between the MJO2 envelope and convectively coupled waves (CCWs) are analyzed to illuminate the dynamical contribution of these synoptic-scale equatorial waves to the WWEs. The authors suggest that different developing processes among WWEs can be attributed to different types of CCWs.
5
Hsu, Cheng-Hsing, Jun-Liang Chen, Shan-Chi Yuan, and Kuang-Yuan Kung. "CFD Simulations on the Rotor Dynamics of a Horizontal Axis Wind Turbine Activated from Stationary." Applied Mechanics 2, no. 1 (March 5, 2021): 147–58. http://dx.doi.org/10.3390/applmech2010009.
Full textAbstract:
The adaptive dynamic mesh, user-defined functions, and six degrees of freedom (6DOF) solver provided in ANSYS FLUENT 14 are engaged to simulate the activating processes of the rotor of the Grumman WS33 wind system. The rotor is activated from stationary to steady operation driven by a steady or periodic wind flow and its kinematic properties and power generation during the activating processes. The angular velocity and angular acceleration are calculated directly by the post-processed real-time 6DOF solver without presuming a known rotating speed to the computational grid frame. The maximum angular velocity of the rotor is approximately proportional to the driving wind speed, and its maximal angular acceleration is also closely proportional to the square of the driving wind speed. The evolution curves of the normalized rotor angular velocities and accelerations are almost identical due to the self-similarity properties of the rotor angular velocities and accelerations. The angular velocity of the rotor will reach its steady value. One can use these steady angular velocities to predict the mechanical power generations of the rotor. The momentum analysis theory and the blade element momentum method are applied to predicted power generations and reveal good agreements with experimental data in the low wind speed range.
6
Zhang, Yanbing, Tiehua Ma, Hongyan Zhang, Yaoyan Wu, Zhibo Wu, and Junzhi Yu. "Ground Simulation Tests in Two-Dimensional Dynamic Acceleration Environment." Applied Sciences 10, no. 3 (January 30, 2020): 910. http://dx.doi.org/10.3390/app10030910.
Full textAbstract:
Acceleration environment (AE) simulation tests have been widely applied in various areas such as aviation, space, environmental medicine, medical science, biomedicine, and materials. Most existing AE simulation test methods adopt impact and flight overload simulation separately, which cannot realize the synchronous controllable loading of two-dimensional (2-D) dynamic acceleration. In this paper, we propose and implement an AE simulation test method using an air-cannon-started compound centrifugal turntable. Specifically, our method emphasizes two processes, i.e., orderly transition from impact overload to steady-state overload and synchronous loading of 2-D dynamic AE. To further facilitate the method verification in AE, we develop a specialized simulation test platform. During field tests, axial acceleration of the unit being tested reached 20 g in 0.12 s at the launching stage and radial acceleration raised from zero g to 40 g in 0.5 s at the flight stage, achieving simulation of the 2-D dynamic AE. The obtained results show the effectiveness of the proposed simulation method, shedding light on updated design and control of impact simulation tests on the structures of crystal oscillator circuit, acceleration sensors, and related instruments.
7
Mašek, Bohuslav, Hana Jirková, Jiří Malina, and Štěpán Jeníček. "Advanced Material-Technological Modelling of Complex Dynamic Thermomechanical Processes." Materials Science Forum 654-656 (June 2010): 1594–97. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1594.
Full textAbstract:
Material-technological modelling has made great progress over recent years, thanks to the new possibilities opened up by developments in sensor technology, and especially in new methods of control, supported by innovative electronic elements and electronic circuits. One such device, developed for material-technological modelling, is the thermomechanical simulator which was established in the laboratories of the Research Centre of Forming Technologies FORTECH, in Pilsen, in the Czech Republic. Thanks to new knowledge and technical equipment the majority of technological processes or even technological chains can be modelled. The most considerable and most important innovation in the material-technological modelling process is the significant acceleration and increased precision of the modelling process. The present technology even allows modelling of highly dynamic processes, such as wire rolling including all thermodynamical effects. This paper presents the broad possibilities of the most modern material-technological modelling. The process of detecting technical and manufacturing problems during rolling and the possibilities of failure elimination are introduced in a practical example.
8
Jin, Yong, Daehyeon Kim, Sugeun Jeong, and Hoyeon Kim. "Analysis of Multilayered Ground Amplification Characteristics by Scaled-Down Model Tests." Applied Sciences 12, no. 7 (March 28, 2022): 3432. http://dx.doi.org/10.3390/app12073432.
Full textAbstract:
During an earthquake, seismic waves travel through different media through the source to reach the surface. It is very necessary to study the dynamic characteristics of soil between different layers during earthquake. In order to explore the dynamic characteristics of soil under the action of ground seismic input motion, scaled-down model tests were carried out through 1 g shaking table tests based on a laminar shear box. After creating a dense lower ground with a sample of mixed silica and silty soil, and a loose upper ground with sand, the acceleration was measured by applying seismic loading through the 1 g shaking table test. Through the Peak ground acceleration, Spectral acceleration and Spectral acceleration amplification factors, the magnification variation and differences of each depth of the model and the dynamic characteristics of soil between different layers were displayed. In order to verify the reliability of the experimental data, a one-dimensional ground response analysis was carried out using DEEPSOIL software. The approximate results obtained by comparing each other can provide a basis for the accuracy of the experimental results.
9
Popescu, Radu. "Finite element assessment of the effects of seismic loading rate on soil liquefaction." Canadian Geotechnical Journal 39, no. 2 (April 1, 2002): 331–44. http://dx.doi.org/10.1139/t01-098.
Full textAbstract:
The influence of frequency content of seismic excitation on the extent and pattern of pore-water pressure build-up in saturated soil deposits is addressed. Seismic acceleration time histories are generated as uniformly modulated nonstationary stochastic processes, in accordance with prescribed response spectra and prescribed modulating functions. Based on numerical examples, it is shown that the interplay between the frequency content of seismic excitation and the dynamic characteristics of the soil system and their evolution during and after the earthquake have important implications on the dynamic response.Key words: seismic motion, frequency content, finite elements, soil dynamics.
10
Zhang, Xu, Yan Ma, Chun Mei Yang, and Li Fu. "Dynamic Analysis and Design of the Rhombic Drive of Stirling Engine." Advanced Materials Research 429 (January 2012): 165–71. http://dx.doi.org/10.4028/www.scientific.net/amr.429.165.
Full textAbstract:
The rhombic drive of Stirling engine has been designed in the article, and motion analysis have been carried out according with the requirements of mechanism design in structure. The kinematics mathematical models have been established for rhombic mechanism and the simulation analyses have been carried with the three-dimensional software for the rhombic drive. It makes a point out the optimum position relationship among the link of the rhombic drive during the four processes of the Stirling cycle, and has conducted a mathematical description of piston displacement, velocity and acceleration which drove by the rhombic drive. The simulation curves have showed the relative relationship of position, velocity and acceleration between the two pistons during the body movement. Based on these researches constructive ideas have been offered to improve the rhombic drive in the paper and laid the root for the optimal design of the Stirling engine in theory.
Dissertations / Theses on the topic "Dynamic processes during acceleration"
1
Кожушко, Андрій Павлович. "Підвищення техніко-економічних показників колісних тракторів з безступінчастими трансмісіями раціональною зміною параметрів регулювання гідромашин в процесі розгону." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/20967.
Full textAbstract:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2016 р.
Дисертацію присвячено підвищенню техніко-економічних показників машинно-тракторних агрегатів з гідрооб'ємно-механічними трансмісіями за рахунок використання раціональних законів зміни параметрів регулювання гідромашин гідрооб'ємної передачі в процесі розгону. Складена комплексна математична модель систем машинно-тракторного агрегату, вдосконалено математичний опис зміни сили тяги на гаку шляхом урахування процесу заглиблення плуга в процесі виходу на технологічний режим при виконанні операції "оранка". Встановлено вплив зміни робочого об'єму гідромотору при різних законах зміни параметрів регулювання гідромашин гідрооб'ємної передачі на динаміку розгону машинно-тракторного агрегату. Визначено вплив зміни часу розгону машинно-тракторного агрегату при різних законах зміни параметрів регулювання гідромашин гідрооб'ємної передачі. Сформовано раціональні закони зміни параметрів регулювання гідромашин гідрооб'ємної передачі, при яких підвищуються техніко-економічні показники машинно-тракторного агрегату.The dissertation for obtaining a scientific degree of Candidate of Science (Technology) on the specialty 05.22.02 – automobiles and tractors. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2016. Dissertation is devoted to improve the technical and economic performance of wheeled tractors with hydrovolumetric mechanical transmission by detecting changes in the parameters of rational regulation of hydromachines during acceleration. Compiled complex mathematical model of the system tractor units improved the mathematical description of the changes tractive force on the hook by taking into account the process of deepening the plow in entering the technological mode of operation "plowing". The influence of changes in the working volume hydraulic parameters changes various laws regulating hydraulic machines hydrovolumetric transmission to dynamics of dispersal tractor unit. The influence of changes in time acceleration tractor unit under various laws of parameters regulating hydraulic machines hydrovolumetric transmission. Formed rational laws change control parameters of hydrovolumetric gear in which the increase of technical and economic parameters of the machine and tractor unit.
2
Кожушко, Андрій Павлович. "Підвищення техніко-економічних показників колісних тракторів з безступінчастими трансмісіями раціональною зміною параметрів регулювання гідромашин в процесі розгону." Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/20971.
Full textAbstract:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2016 р. Дисертацію присвячено підвищенню техніко-економічних показників машинно-тракторних агрегатів з гідрооб'ємно-механічними трансмісіями за рахунок використання раціональних законів зміни параметрів регулювання гідромашин гідрооб'ємної передачі в процесі розгону. Складена комплексна математична модель систем машинно-тракторного агрегату, вдосконалено математичний опис зміни сили тяги на гаку шляхом урахування процесу заглиблення плуга в процесі виходу на технологічний режим при виконанні операції "оранка". Встановлено вплив зміни робочого об'єму гідромотору при різних законах зміни параметрів регулювання гідромашин гідрооб'ємної передачі на динаміку розгону машинно-тракторного агрегату. Визначено вплив зміни часу розгону машинно-тракторного агрегату при різних законах зміни параметрів регулювання гідромашин гідрооб'ємної передачі. Сформовано раціональні закони зміни параметрів регулювання гідромашин гідрооб'ємної передачі, при яких підвищуються техніко-економічні показники машинно-тракторного агрегату.The dissertation for obtaining a scientific degree of Candidate of Science (Technology) on the specialty 05.22.02 – automobiles and tractors. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2016. Dissertation is devoted to improve the technical and economic performance of wheeled tractors with hydrovolumetric mechanical transmission by detecting changes in the parameters of rational regulation of hydromachines during acceleration. Compiled complex mathematical model of the system tractor units improved the mathematical description of the changes tractive force on the hook by taking into account the process of deepening the plow in entering the technological mode of operation "plowing". The influence of changes in the working volume hydraulic parameters changes various laws regulating hydraulic machines hydrovolumetric transmission to dynamics of dispersal tractor unit. The influence of changes in time acceleration tractor unit under various laws of parameters regulating hydraulic machines hydrovolumetric transmission. Formed rational laws change control parameters of hydrovolumetric gear in which the increase of technical and economic parameters of the machine and tractor unit.
3
Fernandes, Ana Miguel. "Dynamic regulation of co-transcriptional processes during neuronal maturation." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21603.
Full textAbstract:
Koordinierte Phosphorylierung der C-terminale Domäne von RNA Polymerase II (RNAPII) ist essentiell für eine effiziente Kupplung von naszierender RNA Synthese und co-transkriptionalem RNA Prozessierens. Zirkuläre RNAs (circRNAs) sind eine neue Klasse von RNA Molekülen mit hoher Prävalenz in neuronalen Zelltypen. Die Biogenese von circRNAs ist noch ungeklärt, insbesondere die Frage warum das Intron upstream der circRNA während der Transkription des circRNA Exons zurückbehalten wird um Rück-Spleißen zu ermöglichen. Verschiede Belege suggerieren, dass unzulängliche Rekrutierung des Spleiceosoms zur circRNA Formation führen kann.
In dieser Arbeit untersuche ich die Mechanismen die zu Defekten in der Erkennung und des Spleißens des Introns upstream der circRNA führen. Mit diesem Ziel erfasste ich die genomweite Verteilung von chromatinassoziierter RNAPII mit verschiedenen Phosphorylierungen, sowie Spleißfaktoren und Transkriptionsreglern mittels ChIP-seq in neuronaler Differenzierung von murinen embryonalen Stammzellen zu dopaminergen und Motoneuronen. Während der gesamten Differenzierung, aber insbesondere in den differenzieren Neuronen, konnten circRNAs detektiert werden. In meiner Arbeit finde ich, dass circRNAs detektiert werden, wenn Gene hohe Levels an mRNA exprimieren und, dass die Produktion von circRNA mit einer Dysbalance zwischen dem Laden der RNA-Polymerase II auf die DNA und dem Rekruitieren der Splice-Maschinerie zusammen hängt. Um funktionell mit den Pausier-Mechanismen der RNA-Polymerase II zu interferieren, habe ich einen ''promotor-proximal-pausing'' Faktor depletiert. Dabei stellte ich fest, dass diese Depletion genügt, um die circRNA Levels in embryonalen Stamzellen zu erhöhen. Die Ergebnisse die in dieser Arbeit gezeigt werden, beschreiben die Beteiligung des Pausierens der RNA-Polymerase II and der Formierung von circRNAs.Coordinated phosphorylation of RNA polymerase II (RNAPII) C-terminal domain is essential for efficient coupling of nascent RNA synthesis with co-transcriptional RNA processing events. Circular RNAs (circRNAs) are a novel class of RNAs whose biogenesis remains ill understood, namely why the upstream intron is not spliced before the circRNA-exon is fully transcribed. Indirect evidence suggests that altered spliceosome recruitment can lead to circRNA formation. To investigate the mechanisms that may be involved in deficient recognition and splicing of introns upstream of exons included in circRNAs, I mapped the chromatin occupancy of RNAPII phosphorylated forms, splicing factors, and transcription regulators by ChIP-seq during mouse ESC differentiation to dopaminergic and spinal motor neurons. CircRNAs are detected throughout differentiation, peaking in differentiated neurons, as expected. I found that circRNAs are detected when genes express high levels of mRNA, and that circRNA production is associated with an imbalance between RNAPII loading and recruitment of the splicing machinery. To mechanistically interfere with pausing mechanisms, I depleted an RNAPII promoter-proximal pausing factor, and found that it was sufficient to increase the formation of circRNAs in stem cells. Results shown in this work implicate RNAPII regulation mechanisms in the formation of circRNAs.
4
Figueroa, Michael. "Dynamic Analysis of a Light Wood-Framed Structure during Fire Conditions." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-theses/777.
Full textAbstract:
The purpose of this project is to create a theoretical dynamic analysis model to assess the dynamic response of light, wood-framed structures before and after fire conditions. This information is useful for predicting the damage to structural integrity due to a fire. The mass and stiffness matrices used for the dynamic model are derived from a standard residential building created for an existing project at WPI funded through the DHS/FEMA/USFA Assistance to Firefighters Grant program. The damping matrix is derived via the Rayleigh Damping Method using the mass and stiffness matrices obtained through SAP. Then, theoretical impact forces are applied to the developed dynamic model, and the acceleration response is estimated using Matlab. Both acceleration time history and frequency responses are used as the evaluation method. Finally, the dynamic model is integrated with a fire simulation model to investigate the impact of fire conditions on dynamic responses of residential buildings. The results show that frequencies can shift due to the structural degradation due to fire.
5
Lisman, Peter Jacob. "Slow Isoinertial Cervical Strength Training Does Not Alter Dynamic Stabilization of the Head and Neck During a Standard Football Tackle." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/317.
Full textAbstract:
The sternocleidomastoid (SCM) and upper trapezius (UT) muscles are the primary dynamic stabilizers of the head and neck and likely attenuate head acceleration with direct and indirect impacts. Increasing the strength of the SCM and UT through cervical resistance training has been recommended to prevent concussions in football players. The purpose of this study was to examine the effects of an eight-week isoinertial cervical resistance training program on SCM and UT muscle activity (EMG) and kinematic responses of the head and neck during a standard football tackle in college-aged males. Sixteen college-aged males (21.6 ± 2.8 y, 94.6 ± 13.3 kg) with previous high school football or rugby playing experience completed an eight-week isoinertial cervical resistance training program consisting of three sets of 10 repetitions of neck extension, flexion, right and left lateral flexion at 60-80% of 10 repetition maximum two to three times a week. Isometric cervical strength, neck girth, EMG, and kinematic responses of the head and neck during a standard football tackle were measured before and after training. All kinematic data were gathered using a three-dimensional motion capturing system. Training resulted in 7 and 10% increases in isometric cervical extension and left lateral flexion strength, respectively, but no changes were seen in isometric flexion or right lateral flexion strength or neck girth. Additionally, training had no influence on the EMG responses of the SCM or UT, peak linear (7.23 vs. 7.59 g, p = 0.115; pre- vs. post-training) or angular (431.96 vs. 452.37 rad/s2, p = 0.864) head accelerations during the standard football tackle. The UT demonstrated approximately 40% higher absolute EMG activity than the SCM during tackling both before and after training. Under the current experimental conditions, despite modest increases in isometric cervical extension and left lateral flexion strength, the eight-week isoinertial cervical resistance training program failed to augment dynamic stabilization of the head and neck during a standard football tackle in college-aged males. Future research should examine the effects of both slow speed load-intensive and high speed low-to-moderate load intensity isoinertial training as well as plyometric training in decreasing head acceleration during football tackling for injury prevention purposes.
6
Fernandes, Ana Miguel [Verfasser]. "Dynamic regulation of co-transcriptional processes during neuronal maturation / Ana Miguel Fernandes." Berlin : Humboldt-Universität zu Berlin, 2020. http://d-nb.info/1216502897/34.
Full text
7
MARTÍN, DE AZCÁRATE LAURA. "Muscle contributions to body mass center acceleration during the first stance of sprint running." Thesis, KTH, Mekanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-250027.
Full textAbstract:
The best results in a sprint running are based upon covering the distance in the shortest possible time, and therefore performance has to be maximized. To achieve the best performance, the sprinter has to develop the greatest forward acceleration, reach his/her maximal speed, and keep it over the run. The greatest anteroposterior acceleration is generated in the first stance of a sprint due to the greatest propulsive force production. Thus, the first step was selected to study induced accelerations by the main muscles of the lower limb. Since a wider step width was founded out to help with force generation during long foot-ground contacts, an elite sprinter with a wide step width was selected. Ankle plantarflexors were the main contributors to body propulsion and support, while knee extensors decelerated forward propulsion but induced medial accelerations. Hip extensors and hip adductors did not offer a remarkable contribution to body COM acceleration in any direction.
8
Chou, Yen-Liang. "Relaxation phenomena during non-equilibrium growth." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/28574.
Full textAbstract:
The surface width, a global quantity that depends on time, is used to characterize the temporal evolution of growing surfaces. One of the most successful concepts for describing the property of the surface width is the famous Family-Vicsek scaling relation. We discuss an extended scaling relation that yields a complete description for various growth models.
For two linear Langevin equations, namely the Edwards-Wilkinson equation and the Mullins-Herring equation, we furthermore study analytically the behavior of global quantities related to the surface width or to a quantity which is conjugated to the diffusion constant. The global quantities depend in a non-trivial way on two different times. We discuss the dynamical scaling forms of global correlation and response functions.
For global functions related to the surface width, we show that the scaling behavior of the response can depend on how the system is perturbed. Different dynamic regimes, characterized by a power-law or by an exponential relaxation, are identified, and a dynamic phase diagram is constructed. We discuss global fluctuation-dissipation ratios and how to use them for the characterization of non-equilibrium growth processes. We also numerically study the same two-time quantities for the non-linear Kardar-Parisi-Zhang equation.
For global functions related to the quantity which is conjugated to the diffusion constant of the linear Langevin equations, we show that the integrated response is proportional to the correlation in the linear response regime. In the aging regime, the autocorrelation and autoresponse exponents are identical and the aging exponent for the response is equal to the aging exponent for the correlation. We investigate the non-equilibrium fluctuation-dissipation theorem for non-equilibrium states based on this quantity. In the non-linear response regime a certain dissipation-fluctuation ratio approximates unity for small waiting times but approaches the ratio of perturbed and unperturbed diffusion constants for larger waiting times.Ph. D.
9
Kirby, Tyler. "GLOBAL-SCALE ANALYSIS OF THE DYNAMIC TRANSCRIPTIONAL ADAPTATIONS WITHIN SKELETAL MUSCLE DURING HYPERTROPHIC GROWTH." UKnowledge, 2015. http://uknowledge.uky.edu/physiology_etds/22.
Full textAbstract:
Skeletal muscle possesses remarkable plasticity in responses to altered mechanical load. An established murine model used to increase mechanical load on a muscle is the surgical removal of the gastrocnemius and soleus muscles, thereby placing a functional overload on the plantaris muscle. As a consequence, there is hypertrophic growth of the plantaris muscle. We used this model to study the molecular mechanisms regulating skeletal muscle hypertrophy.
Aged skeletal muscle demonstrates blunted hypertrophic growth in response to functional overload. We hypothesized that an alteration in gene expression would contribute to the blunted hypertrophic response observed with aging. However, the difference in gene expression was modest, with cluster analysis showing a similar pattern of expression between the two groups. Despite ribosomal protein gene expression being higher in the aged group, ribosome biogenesis was significantly lower in aged compared with young skeletal muscle in response to the hypertrophic stimulus (50% versus 2.5-fold, respectively). The failure to fully up-regulate pre-47S ribosomal RNA (rRNA) expression in old skeletal muscle undergoing hypertrophy indicated ribosomal DNA transcription by RNA polymerase I was impaired. Contrary to our hypothesis, the findings of the study suggest that impaired ribosome biogenesis was a primary factor underlying the blunted hypertrophic response observed in old skeletal muscle rather than dramatic differences in gene expression.
As it appears ribosomal biogenesis may limit muscle hypertrophy, we assessed the dynamic changes in global transcriptional output during muscle hypertrophy, as the majority of global transcription is dedicated to ribosome biogenesis during periods of rapid growth. Metabolic labeling of nascent RNA using 5-ethynyl uridine permitted the assessment of cell type specific changes in global transcription and how this transcription is distributed within the myofiber. Using this approach, we demonstrate that myofibers are the most transcriptionally active cell-type in skeletal muscle, and furthermore, myonuclei are able to dramatically upregulate global transcription during muscle hypertrophy. Interestingly, the myonuclear accretion that occurs with hypertrophy actually results in lower transcriptional output across nuclei within the muscle fiber relative to sham conditions. These findings argue against the notion that nuclear accretion in skeletal muscle is necessary to increase the transcriptional capacity of the cell in order to support a growth response.
10
Vilaplana, Francisco. "Modelling the degradation processes in high-impact polystyrene during the first use and subsequent recycling." Licentiate thesis, Stockholm : Institutionen för fiber- och polymerteknologi, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4407.
Full textBooks on the topic "Dynamic processes during acceleration"
1
Rubtsov, Nickolai, Mikhail Alymov, Alexander Kalinin, Alexey Vinogradov, Alexey Rodionov, and Kirill Troshin. Remote studies of combustion and explosion processes based on optoelectronic methods. au: AUS PUBLISHERS, 2022. http://dx.doi.org/10.26526/monography_62876066a124d8.04785158.
Full textAbstract:
The main objective of this book is to acquaint the reader with the main modern problems of
the multisensor data analysis and opportunities of the hyperspectral shooting being carried out in the
wide range of wavelengths from ultraviolet to the infrared range, visualization of the fast combustion
processes of flame propagation and flame acceleration, the limit phenomena at flame ignition and
propagation. The book can be useful to students of the high courses and scientists dealing with problems
of optical spectroscopy, vizualisation, digital recognizing images and gaseous combustion.
The main goal of this book is to bring to the attention of the reader the main modern
problems of multisensory data analysis and the possibilities of hyperspectral imaging, carried out
in a broad wave-length range from ultraviolet to infrared by methods of visualizing fast combustion
processes, propagation and flames acceleration, and limiting phenomena during ignition and flame
propagation. The book can be useful for students of higher courses and experimental scientists dealing
with problems of optical spectroscopy, visualization, pattern recognition and gas combustion.
2
Kent, Lia, and Rui Feijo, eds. The Dead as Ancestors, Martyrs, and Heroes in Timor-Leste. NL Amsterdam: Amsterdam University Press, 2020. http://dx.doi.org/10.5117/9789463724319.
Full textAbstract:
During the 24-year Indonesian occupation of East Timor, thousands of people died, or were killed, in circumstances that did not allow the required death rituals to be performed. Since the nation’s independence, families and communities have invested considerable time, effort and resources in fulfilling their obligations to the dead. These obligations are imbued with urgency because the dead are ascribed agency and can play a benevolent or malevolent role in the lives of the living. These grassroots initiatives run, sometimes critically, in parallel with official programs that seek to transform particular dead bodies into public symbols of heroism, sacrifice and nationhood. The Dead as Ancestors, Martyrs, and Heroes in Timor-Leste focuses on the dynamic interplay between the potent presence of the dead in everyday life and their symbolic usefulness to the state. It underlines how the dead shape relationships amongst families, communities and the nation-state, and open an important window into — are in fact pivotal to — processes of state and nation formation.
3
Mitchell, Thomas M., Marion Y. Thomas, and Harsha S. Bhat. Fault Zone Dynamic Processes: Evolution of Fault Properties During Seismic Rupture. American Geophysical Union, 2017.
Find full text
4
Mitchell, Thomas M., Marion Y. Thomas, and Harsha S. Bhat. Fault Zone Dynamic Processes: Evolution of Fault Properties During Seismic Rupture. American Geophysical Union, 2017.
Find full text
5
The Use of Systems Engineering Processes and Tools to Develop a System Dynamic Simulation Model of Engineering Support During the Development Phase of an Acquisition Program. Storming Media, 2001.
Find full text
6
Herzog, Tamar. Identities and Processes of Identification in the Atlantic World. Edited by Nicholas Canny and Philip Morgan. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780199210879.013.0028.
Full textAbstract:
We tend to think about the inhabitants of the Atlantic world as members of discrete groups. We thus argue that ‘Spaniards’ had encountered ‘Indians’, ‘Europeans’ competed with one another, and ‘Africans’ were imported as slaves. Although these categories may be meaningful to us, like all identities and processes of identification, they were dynamic constructions in constant flux. Having gradually emerged during the early modern period and to a great extent because of the engagement with the Atlantic world, their creation involved both confrontation and dialogue and it allowed for competing interpretations. Not only were these identities and processes of identification highly complex, other group solidarities that were just as important — such as the division between people of different religions, nobles and commoners, local citizens and foreigners — mediated between them, on occasions breaking them apart. This article discusses identities and processes of identification in the Atlantic world. It also examines how people inhabiting the Atlantic world are differentiated according to religion.
7
Larsen, Christa, Jenny Kipper, Alfons Schmid, and Ciprian Panzaru, eds. Transformations of Regional and Local Labour Markets Across Europe in Pandemic and Post-Pandemic Times. Rainer Hampp Verlag, 2021. http://dx.doi.org/10.5771/9783957104007.
Full textAbstract:
The European Network on Regional Labour Market Monitoring publishes annual anthologies to gather perspectives from all over Europe and beyond on current topics related to regional and local labour markets. In the anthology of 2021, over 30 network members from ten countries reflect on the effects of the COVID-19 pandemic and state interventions or other measures in different localities and circumstances. They provide analyses on a variety of framework conditions of regional and local labour markets and their influence on the effects of the COVID-19 pandemic. Furthermore, the authors shed light on state interventions and other measures from a comparative perspective. Discussions on the acceleration of social inequality, digitalisation and structural changes during the COVID-19 pandemic complement their multifaceted approaches. Overall, the authors provide information on data, as well as methodological and conceptual approaches that can be applied in regional and local labour market observatories to help regions and localities in their processes of digital, social and sustainable transition.
8
Puttler, Leon I., Robert A. Zucker, and Hiram E. Fitzgerald. Developmental Science, Alcohol Use Disorders, and the Risk–Resilience Continuum. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190676001.003.0001.
Full textAbstract:
The origins and expression of addiction are best understood within the context of developmental processes and dynamic systems organization and change. For some individuals, these dynamic processes lead to risk cumulative or cascade effects that embody adverse childhood experiences that exacerbate risk; predict early onset of drinking, smoking, or other substance use; and often lead to a substance use disorder (SUD) during the transitions to adolescence and emergent adulthood. In other cases, protective factors within or outside of the individual’s immediate family enable embodiment of normative stress regulatory systems and neural networks that support resilience and prevention of SUDs. A case study is provided to illustrate these processes and principles of the organization of addictive behavior. Finally, a model of risk to resilience captures the flow of development and the extent to which individual-experience relationships contribute to risk and resilience.
9
Leech-Wilkinson, Daniel. Musical shape and feeling. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199351411.003.0028.
Full textAbstract:
The concept of shape is widely used by musicians in talking and thinking about performance, yet the mechanisms that afford links between music and shape are little understood. Work on the psychodynamics of everyday life by Daniel Stern and on embodiment by Mark Johnson suggests relationships between the multiple dynamics of musical sound and the dynamics of feeling and motion. Recent work on multisensory and precognitive sensory perception and on the role of bimodal neurons in the sensorimotor system helps to explain how shape, as a percept representing changing quantity in any sensory mode, may be invoked by dynamic processes at many stages of perception and cognition. These processes enable ‘shape’ to do flexible and useful work for musicians needing to describe the quality of musical phenomena that are fundamental to everyday musical practice and yet too complex to calculate during performance.
10
Anger, Klaus, Steffen Harzsch, and Martin Thiel, eds. Developmental Biology and Larval Ecology. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190648954.001.0001.
Full textAbstract:
This volume examines Developmental Biology and Larval Ecology, Chapters in this volume synthesize our current understanding of early crustacean development from the egg through the embryonic and larval phase. The first part of this volume focuses on the fundamental aspects of crustacean embryonic development. The second part of the book provides an account of the larval phase of crustaceans and describes processes that influence the development from hatching to an adult-like juvenile. The third and final part of the book explores ecological interactions during the planktonic phase and how crustacean larvae manage to find food, navigate the dynamic water column, and avoid predators in a medium that offers few refuges. Collectively, these fifteen chapters provide a thorough overview of our present knowledge across the major themes in crustacean developmental biology and larval ecology. We expect this volume will be valuable to scholars and students who are interested in gaining deeper insights into the processes that lead from a single cell to subsequent stages of life and how - growing organisms face the challenges posed by their environment.
Book chapters on the topic "Dynamic processes during acceleration"
1
Rubtsov, Nickolai, Mikhail Alymov, Alexander Kalinin, Alexey Vinogradov, Alexey Rodionov, and Kirill Troshin. "Determining the gas-dynamic and kinetic features of the penetration of methane-oxygen flames through obstacles by using 4D spectroscopy and high-speed filming." In Remote studies of combustion and explosion processes based on optoelectronic methods, 152–201. au: AUS PUBLISHERS, 2022. http://dx.doi.org/10.26526/chapter_62876066c1f968.61934614.
Full textAbstract:
The main objective of this book is to acquaint the reader with the main modern problems of the multisensor data analysis and opportunities of the hyperspectral shooting being carried out in the wide range of wavelengths from ultraviolet to the infrared range, visualization of the fast combustion processes of flame propagation and flame acceleration, the limit phenomena at flame ignition and propagation. The book can be useful to students of the high courses and scientists dealing with problems of optical spectroscopy, vizualisation, digital recognizing images and gaseous combustion. The main goal of this book is to bring to the attention of the reader the main modern problems of multisensory data analysis and the possibilities of hyperspectral imaging, carried out in a broad wave-length range from ultraviolet to infrared by methods of visualizing fast combustion processes, propagation and flames acceleration, and limiting phenomena during ignition and flame propagation. The book can be useful for students of higher courses and experimental scientists dealing with problems of optical spectroscopy, visualization, pattern recognition and gas combustion.
2
Passelègue, François X., Soumaya Latour, Alexandre Schubnel, Stefan Nielsen, Harsha S. Bhat, and Raúl Madariaga. "Influence of Fault Strength on Precursory Processes During Laboratory Earthquakes." In Fault Zone Dynamic Processes, 229–42. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119156895.ch12.
Full text
3
Tanaka, Ken-ichi. "Surface Compounds Formed on Single-Crystal Metal Surfaces During Catalysis." In Dynamic Processes on Solid Surfaces, 115–47. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1636-5_6.
Full text
4
Iiyama, J. Toshimichi, Kazuhiro Suzuki, Masaki Akaogi, Tadao Nishiyama, Koichiro Fujimoto, and Yasuhiro Kato. "Material Transfer during Metamorphic Processes: Experimental Approaches." In Dynamic Processes of Material Transport and Transformation in the Earth’s Interior, 119–37. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-3314-2_9.
Full text
5
Pihnastyi, Oleh, Georgii Kozhevnikov, and Pavel Vasyuchenko. "Analysis of Dynamic Stresses During Acceleration and Deceleration of a Conveyor Belt (Maxwell Element Model)." In Integrated Computer Technologies in Mechanical Engineering - 2021, 270–80. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94259-5_24.
Full text
6
Hrytsay, Ihor, and Vadym Stupnytskyy. "Advanced Computerized Simulation and Analysis of Dynamic Processes During the Gear Hobbing." In Lecture Notes in Mechanical Engineering, 85–97. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-40724-7_9.
Full text
7
Fujimoto, M., and L. S. Chou. "Limits of Dynamic Balance Control Derived by Center of Mass Acceleration during Sit-to-Stand Movement." In IFMBE Proceedings, 489–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14515-5_125.
Full text
8
Rubtsov, Nickolai, Mikhail Alymov, Alexander Kalinin, Alexey Vinogradov, Alexey Rodionov, and Kirill Troshin. "Optoelectronic devices and methods for studying combustion and explosion processes." In Remote studies of combustion and explosion processes based on optoelectronic methods, 29–45. au: AUS PUBLISHERS, 2022. http://dx.doi.org/10.26526/chapter_62876066b5f307.71425279.
Full textAbstract:
The main objective of this book is to acquaint the reader with the main modern problems of the multisensor data analysis and opportunities of the hyperspectral shooting being carried out in the wide range of wavelengths from ultraviolet to the infrared range, visualization of the fast combustion processes of flame propagation and flame acceleration, the limit phenomena at flame ignition and propagation. The book can be useful to students of the high courses and scientists dealing with problems of optical spectroscopy, vizualisation, digital recognizing images and gaseous combustion. The main goal of this book is to bring to the attention of the reader the main modern problems of multisensory data analysis and the possibilities of hyperspectral imaging, carried out in a broad wave-length range from ultraviolet to infrared by methods of visualizing fast combustion processes, propagation and flames acceleration, and limiting phenomena during ignition and flame propagation. The book can be useful for students of higher courses and experimental scientists dealing with problems of optical spectroscopy, visualization, pattern recognition and gas combustion.
9
Rubtsov, Nickolai, Mikhail Alymov, Alexander Kalinin, Alexey Vinogradov, Alexey Rodionov, and Kirill Troshin. "The use of high-speed optical multidimensional technique to determine the characteristics of ignition and combustion of 40% H2 - air mix in the presence of platinum metal." In Remote studies of combustion and explosion processes based on optoelectronic methods, 126–51. au: AUS PUBLISHERS, 2022. http://dx.doi.org/10.26526/chapter_62876066bef2a8.05945792.
Full textAbstract:
The main objective of this book is to acquaint the reader with the main modern problems of the multisensor data analysis and opportunities of the hyperspectral shooting being carried out in the wide range of wavelengths from ultraviolet to the infrared range, visualization of the fast combustion processes of flame propagation and flame acceleration, the limit phenomena at flame ignition and propagation. The book can be useful to students of the high courses and scientists dealing with problems of optical spectroscopy, vizualisation, digital recognizing images and gaseous combustion. The main goal of this book is to bring to the attention of the reader the main modern problems of multisensory data analysis and the possibilities of hyperspectral imaging, carried out in a broad wave-length range from ultraviolet to infrared by methods of visualizing fast combustion processes, propagation and flames acceleration, and limiting phenomena during ignition and flame propagation. The book can be useful for students of higher courses and experimental scientists dealing with problems of optical spectroscopy, visualization, pattern recognition and gas combustion.
10
Rubtsov, Nickolai, Mikhail Alymov, Alexander Kalinin, Alexey Vinogradov, Alexey Rodionov, and Kirill Troshin. "Study of the combustion of hydrogen-air and hydrogen-hydrocarbon (C1- C6) -air mixtures over the surface of palladium metal with the combined use of a hyperspectral sensor and high-speed color filming." In Remote studies of combustion and explosion processes based on optoelectronic methods, 202–36. au: AUS PUBLISHERS, 2022. http://dx.doi.org/10.26526/chapter_62876066c51665.20097229.
Full textAbstract:
The main objective of this book is to acquaint the reader with the main modern problems of the multisensor data analysis and opportunities of the hyperspectral shooting being carried out in the wide range of wavelengths from ultraviolet to the infrared range, visualization of the fast combustion processes of flame propagation and flame acceleration, the limit phenomena at flame ignition and propagation. The book can be useful to students of the high courses and scientists dealing with problems of optical spectroscopy, vizualisation, digital recognizing images and gaseous combustion. The main goal of this book is to bring to the attention of the reader the main modern problems of multisensory data analysis and the possibilities of hyperspectral imaging, carried out in a broad wave-length range from ultraviolet to infrared by methods of visualizing fast combustion processes, propagation and flames acceleration, and limiting phenomena during ignition and flame propagation. The book can be useful for students of higher courses and experimental scientists dealing with problems of optical spectroscopy, visualization, pattern recognition and gas combustion.
Conference papers on the topic "Dynamic processes during acceleration"
1
Lam, Paul C., P. Ruby Mawasha, and Ted Conway. "Transient Behavior of Seated Human Body During Input From Caudophalad Acceleration." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2528.
Full textAbstract:
Abstract The objective of this study, is to investigate the dynamic transient response of a four degree-of-freedom lumped parameter model of the seated human body subjected to caudocephalad loading (acceleration from tail to head). The caudocephalad loading used in the model simulated the ejection process of a seated pilot from a high-speed aircraft. During ejection, ejection velocities are high and are developed over short distances hence, the accelerations are also high (10–40 g’s). The model indicates that even though acceleration is applied over short time duration (typically less than 0.25 seconds), serious bodily injury can result due to high dynamic load factor for the frequency range of body resonances.
2
Roy, Hardik, and Rathindranath Maiti. "Dynamics During Speed Ratio Change of a Double Roller Full Toroidal Traction Drive." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72164.
Full textAbstract:
The dynamics of the speed ratio change process of a double roller full toroidal variator (DFTV) is presented. Speed ratio variation process is observed by finding settling time and efficiency during the ratio variation. A numerical model is developed and simulated using computer software. Contact analyses between roller and discs are based on Hertz theory. The traction and spin moment coefficients are estimated using elasto-hydrodynamic lubrication (EHL) theory. Equation for maximum acceleration of output shaft is derived in terms of maximum output torque. Finally, a procedure to obtain maximum efficiency keeping certain dynamic speed ratio change requirements is discussed.
3
Matsumoto, Toshinori, Masatoshi Sato, Tomoyuki Sugiyama, and Yu Maruyama. "Fluid Dynamic Analysis on Hydrogen Deflagration in Vertical Flow Channel With Annular Obstacles." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-67520.
Full textAbstract:
Hydrogen combustion including deflagration and detonation could become a significant threat to the integrity of containment vessel or reactor building in a severe accident of nuclear power stations. In the present study, numerical analyses were carried out for the ENACCEF No.153 test to develop computational techniques to evaluate the flame acceleration phenomenon during the hydrogen deflagration. This experiment investigated flame propagation in the hydrogen-air premixed gas in a vertical channel with flow obstacles. The reactingFoam solver of the open source CFD code, OpenFOAM, was used for the present analysis. Nineteen elementary chemical reactions were considered for the overall process of the hydrogen combustion. For a turbulent flow, renormalization group (RNG) k-ε two-equation model was used in combination with wall functions. Three manners of nodalization were applied and its influences on the flame propagation acceleration were discussed.
4
Yepifanov, Sergiy V., Roman L. Zelenskyi, and Igor Loboda. "Modeling the GTE Under Its Dynamic Heating Conditions." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26258.
Full textAbstract:
A modern gas turbine engine (GTE) is a complex non-linear dynamic system with the mutual effect of gas-dynamic and thermal processes in its components. The engine development requires the precise real-time simulation of all main operating modes. One of the most complex operating modes for modeling is “cold stabilization”, which is the rotors acceleration without completely heated up the turbine elements. The dynamic heating problem is a topical practical issue. Solving the problem requires coordinating a gas-path model with heat and stress models, which is also a significant scientific problem. The phenomenon of interest is the radial clearances change during engines operation and its influence on engines static and dynamic performances. To consider the clearance change, it is necessary to synthesize the quick proceeding stress-state models (QPSSM) of a rotor and a casing for the initial temperature and dynamic heating. The unique feature of the QPSSM of GTEs is separate equation sets, which allow the heat exchange between structure elements and the gas (air) and the displacements of the turbine rotor and the casing. This ability appears as a result of determining the effect of each factor on different structural elements of the engine. The presented method significantly simplifies the model identification, which can be performed based on a precise calculation of the unsteady temperature fields of the structural elements and the variation of the radial clearance. Thus, the present paper addresses a new method to model the engine dynamics considering its heating up. The method is based on the integration of three models: the gas-path dynamics model, the clearance dynamics model and the model of the clearance effect on the efficiency. The paper also comprises the program implementation of the models. The method was tested by applying to a particular turbofan engine.
5
Wei, Yixiong, Qifu Wang, Yingjun Wang, Yunbao Huang, and Linchi Zhang. "Acceleration of Modal Analysis by FMM Based on DRBEM." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70596.
Full textAbstract:
This paper proposes a novel algorithm to accelerate the process of modal analysis in 3D elastodynamic problems in BEM (boundary element method) with high accuracy. Because of low efficiency and high cost, conventional BEM is rarely used for solving 3D elastodynamics problems in engineering problems. With applying the DRBEM (dual reciprocity boundary element method) to form new integral equations of 3D elastodynamics problems to reduce time complexity by using reciprocity method twice, we introduce modified FMM (fast multipole method) to simplify the computation process and improve the efficiency from O(n2) to O(n) in matrix multiplication. The main features in this method are: (1) Position Location (PL) algorithm is used to eliminate one layer of nested loops in conventional FMM, and which achieve a good performance in efficiency; (2) time dimension integrations in the element of matrices are canceled for high efficiency; (3) instead of the interaction between points, we apply point to element interaction method for saving plenty of the CPU cost in modified FMM; (4) it does not need to compute complex dynamic fundamental solutions which are necessary in conventional BEM. In this algorithm, the corresponding eigenvalue problem is solved by Hessenberg matrix and QR reduction algorithm iteratively. We have tested our method in numerical examples during last section, and have observed significant optimal results in efficiency and accuracy.
6
Hou, Senhao, Xiaoqiang Tang, Yuheng Wang, and Dianjun Wang. "Research on Dynamic Characteristics of the High-Speed Cable Force Transmission." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23293.
Full textAbstract:
Abstract During the landing and detection missions of the Moon, Mars, and asteroids, due to the complexity and unpredictability of the landing process, it is necessary and critical to carry out simulation tests on the ground to simulate the stress state during the separation of the backshell from the lander. A high-speed cable-driven mechanism adopted. The cable force is different at the end actuator and the drum. There are many factors causing this difference, such as high acceleration, cable stiffness, cable density, cable length. In this paper, the cable force transmission of spacecraft during high-speed separation is studied. The dynamic model of high-speed cable-driven mechanism is established based on Newton principle, then the trial function is introduced, and the second-order partial differential equation is solved by using the method of space discretization. The force relationship of the cable in the process of motion is obtained, and the influencing factors of the cable force are explored. Finally, the correctness of the research content in this paper is verified by numerical simulation and experiment. The results show that the model can accurately simulate the force state of the cable, and it has guiding significance for the active high-speed separation test of spacecraft.
7
Wang, Pingxin, Xiaoting Rui, Jianshu Zhang, Hailong Yu, and Hongtao Zhu. "Dynamical Optimization of Tracked Vehicle Based on Riccati Transfer Matrix Method and PSO Algorithm." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85733.
Full textAbstract:
Aiming at the problems of complex modeling and low calculation efficiency during dynamical optimization of tracked vehicles, a method for the closed-loop system called Riccati transfer matrix method for multibody system is proposed. In order to reduce the vibration acceleration of track shoes in the driving process, this paper uses the PSO algorithm and utilizes a strategy of decreasing the inertia weight to optimize the structural parameters of tracked vehicles. The research shows that the root mean square of vibration acceleration of track shoes above the support rollers is obviously reduced. This method provides a theoretical reference for the design of tracked vehicles and is beneficial to the dynamic design of complex systems.
8
Zhu, Zi-Qin, Li-Wu Fan, Min-Jie Liu, and Yi Zeng. "Heat Transfer During Constrained Melting of Graphite-Based Nanofluids in a Spherical Capsule." In ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6316.
Full textAbstract:
Transient heat transfer during constrained melting of graphite-based solid-liquid phase change nanofluids in a spherical capsule was investigated experimentally. Nanofluids filled with self-prepared graphite nanosheets (GNSs) were prepared at various loadings up to 1% by weight, using a straight-chain saturated fatty alcohol, i.e., 1-dodecanol (C12H26O), with a nominal melting point of 22 °C as the base fluid. In-house measured thermal properties were adopted for data reduction, including thermal conductivity, dynamic viscosity, latent heat of fusion, specific heat capacity and density. A proper experimental approach depended on volume expansion was figured out to monitor the melting process of nano-enhanced phase change fluid in a spherical capsule indirectly and qualitatively characterize the process. A variety of boundary temperatures were also adopted to vary the intensity of natural convection. It was shown that under low boundary temperatures, a monotonous melting acceleration came into being while increasing the loading due to the monotonously increased thermal conductivity of the nanofluids. While increasing the boundary temperature leads to more intensive natural convection that in turn slowed down melting under the influence of nanoparticles because the contribution by natural convection is significantly suppressed by the dramatically grown dynamic viscosity, e.g., more than 60-fold increase at the loading of 1 wt.%. The melting rate is determined by the competition between the enhanced heat conduction and deteriorated natural convection.
9
Spies, Irina, Axel Schumacher, Stephan Knappmann, Bastian Rheingans, Jolanta Janczak-Rusch, and Lars P. H. Jeurgens. "Acceleration measurements during reactive bonding processes." In 2017 21st European Microelectronics and Packaging Conference (EMPC) & Exhibition. IEEE, 2017. http://dx.doi.org/10.23919/empc.2017.8346881.
Full text
10
Ortega, Arturo, Ausberto Rivera, Ole Jørgen Nydal, and Carl M. Larsen. "On the Dynamic Response of Flexible Risers Caused by Internal Slug Flow." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83316.
Full textAbstract:
Slug flow through flexible risers is a frequent phenomenon which occurs during production of a mixture of oil and gas. The dynamic nature of the slug pattern induces time varying forces, which leads to structural vibrations of the riser. These vibrations can produce large deflections and stresses, which can leave it to fail by fatigue, excessive bending or local buckling. In this work the influence from slug flow on the structural dynamic response of a lazy wave flexible riser is analyzed using a computational tool consisting of one program for calculation of slug flow dynamics, and another program for structural dynamic response. Both programs apply a time integration method, and since slug flow will lead to dynamic motion response of the riser, and riser motion dynamics will influence slug flow dynamics, the two codes need to exchange information during the integration process. Information exchange is established by making a federation based on High Level Architecture (HLA). The federation is composed of SLUGIT and RISANANL. SLUGGIT is a two-phase flow code written in C++ which simulates dynamic slug flow through pipes and riser using a Lagrangian tracking model. RISANANL is a FORTRAN program for static and dynamic structural analysis of slender marine structures based on a finite element formulation. Using the HLA standard these two programs can carry out synchronized time integration and exchange information for each time step. In this work the structural analysis code accomplishes the dynamic response using a linear finite element (FE) formulation. Hence, forces from centripetal acceleration of the internal flow, relative velocity between the riser and surrounding water, and varying gravity of the pipe and content will be accounted for in the dynamic analysis. Displacements, stresses, internal pressure, and outlet flow rates of liquid and gas will be accounted for. The results encourage us to carry out a fully non-linear finite element analysis, in order to have a better understanding of the dynamic behaviour of flexible risers undergoing an unsteady internal two-phase flow.
Reports on the topic "Dynamic processes during acceleration"
1
Chovnyuk, Yuriy, Michail Dikterjuk, Svetlana Komotskaya, and Ivan Kadikalo. Substantiation of equivalent circuits of rota-tion mechanisms of load-lifting cranes, their dynamic analysis and optimization during the processes of starting and braking. Gіrnichі, budіvelnі, dorozhnі ta melіorativnі mashini, April 2019. http://dx.doi.org/10.31493/gbdmm1892.0101.
Full text
2
Tsur, Yacov, David Zilberman, Uri Shani, Amos Zemel, and David Sunding. Dynamic intraseasonal irrigation management under water scarcity, water quality, irrigation technology and environmental constraints. United States Department of Agriculture, March 2007. http://dx.doi.org/10.32747/2007.7696507.bard.
Full textAbstract:
In this project we studied optimal use and adoption of sophisticated irrigation technologies. The stated objectives in the original proposal were to develop a conceptual framework for analyzing intra-season timing of water application rates with implications for crop and irrigation technology selection. We proposed to base the analysis on an intra-seasonal, dynamic, agro-economic model of plants' water demand, paying special attention to contamination of groundwater and soil in intensively cultivated areas that increasingly rely on water of lesser quality. The framework developed in the project integrates (i) a bio-physical model of water flow in the vadose zone and water uptake by plants and yield response with (ii) a dynamic management model to determine the optimal intra-season irrigation policy. It consists of a dynamic optimization model to determine irrigation rates at each point of time during the growing season and aggregation relating harvested yield with accumulated water input. The detailed dynamic approach provides a description of yield production processes at the plant’s level, and serves to determine intra-season irrigation decisions. Data derived from extensive field experiments were used to calibrate the model's parameters. We use the framework to establish the substitution between irrigation technology (capital) and water inputs; this is an important property of irrigation water productivity that has been overlooked in the literature. Another important feature investigated is the possibility to substitute fresh and saline water with a minimal productivity loss. The effects of soil properties and crop characteristics on optimal technology adoption have also been studied. We find that sandy soil, with low water holding capacity, is more conducive to adoption of sophisticated drip irrigation, as compared to heavier soils in which drainage losses are significantly smaller.
3
Yaron, Zvi, Abigail Elizur, Martin Schreibman, and Yonathan Zohar. Advancing Puberty in the Black Carp (Mylopharyngodon piceus) and the Striped Bass (Morone saxatilis). United States Department of Agriculture, January 2000. http://dx.doi.org/10.32747/2000.7695841.bard.
Full textAbstract:
Both the genes and cDNA sequences encoding the b-subunits of black carp LH and FSH were isolated, cloned and sequenced. Sequence analysis of the bcFSHb and LHb5'flanking regions revealed that the promoter region of both genes contains canonical TATA sequences, 30 bp and 17 bp upstream of the transcription start site of FSHb and LHb genes, respectively. In addition, they include several sequences of cis-acting motifs, required for inducible and tissue-specific transcriptional regulation: the gonadotropin-specific element (GSE), GnRH responsive element (GRE), half sites of estrogen and androgen response elements, cAMP response element, and AP1. Several methods have been employed by the Israeli team to purify the recombinant b subunits (EtOH precipitation, gel filtration and lentil lectin). While the final objective to produce pure recombinantGtH subunits has not yet been achieved, we have covered much ground towards this goal. The black carp ovary showed a gradual increase in both mass and oocyte diameter. First postvitellogenic oocytes were found in 5 yr old fish. At this age, the testes already contained spermatozoa. The circulating LH levels increased from 0.5 ng/ml in 4 yr old fish to >5ng/ml in 5 yr old fish. In vivo challenge experiments in black carp showed the initial LH response of the pituitary to GnRH in 4 yr old fish. The response was further augmented in 5 yr old fish. The increase in estradiol level in response to gonadotropic stimulation was first noted in 4 yr old fish but this response was much stronger in the following year. In vivo experiments on the FSHb and LHb mRNA levels in response to GnRH were carried out on common carp as a model for synchronom spawning cyprinids. These experiments showed the prevalence of FSHP in maturing fish while LHP mRNA was prevalent in mature fish, especially in females. The gonadal fat-pad was found to originate from the retroperitoneal mesoderm and not from the genital ridge, thus differing from that reported in certain amphibians This tissue possibly serves as the major source of sex steroids in the immature black carp. However, such a function is taken over by the developing gonads in 4 yr old fish. In the striped bass, we described the ontogeny of the neuro-endocrine parameters along the brain-pituitary-gonadal axis during the first four years of life, throughout gonadal development and the onset of puberty. We also described the responsiveness of the reproductive axis to long-term hormonal manipulations at various stages of gonadal development. Most males reached complete sexual maturity during the first year of life. Puberty was initiated during the third year of life in most females, but this first reproductive cycle did not lead to the acquisition of full sexual maturity. This finding indicates that more than one reproductive cycle may be required before adulthood is reached. Out of the three native GnRHs present in striped bass, only sbGnRH and cGnRH II increased concomitantly with the progress of gonadal development and the onset of puberty. This finding, together with data on GtH synthesis and release, suggests that while sbGnRH and cGnRH II may be involved in the regulation of puberty in striped bass, these neuropeptides are not limiting factors to the onset of puberty. Plasma LH levels remained low in all fish, suggesting that LH plays only a minor role in early gonadal development. This hypothesis was further supported by the finding that experimentally elevated plasma LH levels did not result in the induction of complete ovarian and testicular development. The acquisition of complete puberty in 4 yr old females was associated with a rise in the mRNA levels of all GtH subunit genes, including a 218-fold increase in the mRNA levels of bFSH. mRNA levels of the a and PLH subunits increased only 11- and 8-fold, respectively. Although data on plasma FSH levels are unavailable, the dramatic increase in bFSH mRNA suggests a pivotal role for this hormone in regulating the onset and completion of puberty in striped bass. The hormonal regulation of the onset of puberty and of GtH synthesis and release was studied by chronic administration of testosterone (T) and/or an analog of gonadotropin-releasing hormone (G). Sustained administration of T+G increased the mRNA levels of the PLH subunit to the values characteristic of sexually mature fish, and also increased the plasma levels of LH. However, these changes did not result in the acceleration of sexual maturation. The mRNA levels of the bFSH subunit were slightly stimulated, but remained about 1/10 of the values characteristic of sexually mature fish. It is concluded that the stimulation of FSH gene expression and release does not lead to the acceleration of sexual maturity, and that the failure to sufficiently stimulate the bFSH subunit gene expression may underlie the inability of the treatments to advance sexual maturity. Consequently, FSH is suggested to be the key hormone to the initiation and completion of puberty in striped bass. Future efforts to induce precocious puberty in striped bass should focus on understanding the regulation of FSH synthesis and release and on developing technologies to induce these processes. Definite formulation of hormonal manipulation to advance puberty in the striped bass and the black carp seems to be premature at this stage. However, the project has already yielded a great number of experimental tools of DNA technology, slow-release systems and endocrine information on the process of puberty. These systems and certain protocols have been already utilized successfully to advance maturation in other fish (e.g. grey mullet) and will form a base for further study on fish puberty.
4
Snyder, Victor A., Dani Or, Amos Hadas, and S. Assouline. Characterization of Post-Tillage Soil Fragmentation and Rejoining Affecting Soil Pore Space Evolution and Transport Properties. United States Department of Agriculture, April 2002. http://dx.doi.org/10.32747/2002.7580670.bard.
Full textAbstract:
Tillage modifies soil structure, altering conditions for plant growth and transport processes through the soil. However, the resulting loose structure is unstable and susceptible to collapse due to aggregate fragmentation during wetting and drying cycles, and coalescense of moist aggregates by internal capillary forces and external compactive stresses. Presently, limited understanding of these complex processes often leads to consideration of the soil plow layer as a static porous medium. With the purpose of filling some of this knowledge gap, the objectives of this Project were to: 1) Identify and quantify the major factors causing breakdown of primary soil fragments produced by tillage into smaller secondary fragments; 2) Identify and quantify the. physical processes involved in the coalescence of primary and secondary fragments and surfaces of weakness; 3) Measure temporal changes in pore-size distributions and hydraulic properties of reconstructed aggregate beds as a function of specified initial conditions and wetting/drying events; and 4) Construct a process-based model of post-tillage changes in soil structural and hydraulic properties of the plow layer and validate it against field experiments. A dynamic theory of capillary-driven plastic deformation of adjoining aggregates was developed, where instantaneous rate of change in geometry of aggregates and inter-aggregate pores was related to current geometry of the solid-gas-liquid system and measured soil rheological functions. The theory and supporting data showed that consolidation of aggregate beds is largely an event-driven process, restricted to a fairly narrow range of soil water contents where capillary suction is great enough to generate coalescence but where soil mechanical strength is still low enough to allow plastic deforn1ation of aggregates. The theory was also used to explain effects of transient external loading on compaction of aggregate beds. A stochastic forInalism was developed for modeling soil pore space evolution, based on the Fokker Planck equation (FPE). Analytical solutions for the FPE were developed, with parameters which can be measured empirically or related to the mechanistic aggregate deformation model. Pre-existing results from field experiments were used to illustrate how the FPE formalism can be applied to field data. Fragmentation of soil clods after tillage was observed to be an event-driven (as opposed to continuous) process that occurred only during wetting, and only as clods approached the saturation point. The major mechanism of fragmentation of large aggregates seemed to be differential soil swelling behind the wetting front. Aggregate "explosion" due to air entrapment seemed limited to small aggregates wetted simultaneously over their entire surface. Breakdown of large aggregates from 11 clay soils during successive wetting and drying cycles produced fragment size distributions which differed primarily by a scale factor l (essentially equivalent to the Van Bavel mean weight diameter), so that evolution of fragment size distributions could be modeled in terms of changes in l. For a given number of wetting and drying cycles, l decreased systematically with increasing plasticity index. When air-dry soil clods were slightly weakened by a single wetting event, and then allowed to "age" for six weeks at constant high water content, drop-shatter resistance in aged relative to non-aged clods was found to increase in proportion to plasticity index. This seemed consistent with the rheological model, which predicts faster plastic coalescence around small voids and sharp cracks (with resulting soil strengthening) in soils with low resistance to plastic yield and flow. A new theory of crack growth in "idealized" elastoplastic materials was formulated, with potential application to soil fracture phenomena. The theory was preliminarily (and successfully) tested using carbon steel, a ductile material which closely approximates ideal elastoplastic behavior, and for which the necessary fracture data existed in the literature.
5
Chen, Junping, Zach Adam, and Arie Admon. The Role of FtsH11 Protease in Chloroplast Biogenesis and Maintenance at Elevated Temperatures in Model and Crop Plants. United States Department of Agriculture, May 2013. http://dx.doi.org/10.32747/2013.7699845.bard.
Full textAbstract:
specific objectives of this proposal were to: 1) determine the location, topology, and oligomerization of FtsH11 protease; 2) identify the substrate/s of FtsH11 and the downstream components involved in maintaining thermostability of chloroplasts; 3) identify new elements involved in FtsH11 protease regulatory network related to HT adaptation processes in chloroplast; 4) Study the role of FtsH11 homologs from crop species in HT tolerance. Background to the topic: HT-tolerant varieties that maintain high photosynthetic efficiency at HT, and cope better with daily and seasonal temperature fluctuations are in great need to alleviate the effect of global warming on food production. Photosynthesis is a very complex process requiring accurate coordination of many complex systems and constant adjustments to the changing environments. Proteolytic activities mediated by various proteases in chloroplast are essential part of this process and critical for maintaining normal chloroplast functions under HT. However, little is known about mechanisms that contribute to adaptation of photosynthetic processes to HT. Our study has shown that a chloroplast-targeted Arabidopsis FtsH11 protease plays an essential and specific role in maintaining thermostability of thylakoids and normal photosynthesis at moderate HT. We hypothesized that FtsH11 homologs recently identified in other plant species might have roles similarly to that of AtFtsH1. Thus, dissecting the underlying mechanisms of FtsH11 in the adaptation mechanisms in chloroplasts to HT stress and other elements involved will aid our effort to produce more agricultural products in less favorable environments. Major conclusions, solutions, achievements - Identified the chloroplast inner envelope membrane localization of FtsH11. - Revealed a specific association of FtsH11 with the a and b subunits of CPN60. - Identified the involvement of ARC6, a protein coordinates chloroplast division machineries in plants, in FtsH11 mediated HT adaptation process in chloroplast. -Reveal possible association of a polyribonucleotide nucleotidyltransferase (cpPNPase), coded by At3G03710, with FtsH11 mediated HT adaptation process in chloroplast. - Mapped 4 additional loci in FtsH11 mediated HT adaptation network in chloroplast. - Demonstrated importance of the proteolytic activity of FtsH11 for thermotolerance, in addition to the ATPase activity. - Demonstrated a conserved role of plant FtsH11 proteases in chloroplast biogenesis and in maintaining structural and functional thermostability of chloroplast at elevated temperatures. Implications, both scientific and agricultural:Three different components interacting with FtsH11 were identified during the course of this study. At present, it is not known whether these proteins are directly involved in FtsH11mediated thermotolerance network in chloroplast and/or how these elements are interrelated. Studies aiming to connect the dot among biological functions of these networks are underway in both labs. Nevertheless, in bacteria where it was first studied, FtsH functions in heat shock response by regulating transcription level of σ32, a heat chock factor regulates HSPsexpression. FtsH also involves in control of biosynthesis of membrane components and quality control of membrane proteins etc. In plants, both Arc 6 and CPN60 identified in this study are essential in chloroplast division and developments as mutation of either one impairs chloroplast division in Arabidopsis. The facts that we have found the specific association of both α and β CPN60 with FtsH11 protein biochemically, the suppression/ enhancement of ftsh11 thermosensitive phenotype by arc6 /pnp allele genetically, implicate inter-connection of these networks via FtsH11 mediated network(s) in regulating the dynamic adaptation processes of chloroplast to temperature increases at transcriptional, translational and post-translational levels. The conserved role of FtsH11 proteases in maintaining thermostability of chloroplast at HT demonstrated here provides a foundation for improving crop photosynthetic performance at high temperatures.
6
Hovav, Ran, Peggy Ozias-Akins, and Scott A. Jackson. The genetics of pod-filling in peanut under water-limiting conditions. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597923.bard.
Full textAbstract:
Pod-filling, an important yield-determining stage is strongly influenced by water stress. This is particularly true for peanut (Arachishypogaea), wherein pods are developed underground and are directly affected by the water condition. Pod-filling in peanut has a significant genetic component as well, since genotypes are considerably varied in their pod-fill (PF) and seed-fill (SF) potential. The goals of this research were to: Examine the effects of genotype, irrigation, and genotype X irrigation on PF and SF. Detect global changes in mRNA and metabolites levels that accompany PF and SF. Explore the response of the duplicate peanut pod transcriptome to drought stress. Study how entire duplicated PF regulatory processes are networked within a polyploid organism. Discover locus-specific SNP markers and map pod quality traits under different environments. The research included genotypes and segregating populations from Israel and US that are varied in PF, SF and their tolerance to water deficit. Initially, an extensive field trial was conducted to investigate the effects of genotype, irrigation, and genotype X irrigation on PF and SF. Significant irrigation and genotypic effect was observed for the two main PF related traits, "seed ratio" and "dead-end ratio", demonstrating that reduction in irrigation directly influences the developing pods as a result of low water potential. Although the Irrigation × Genotype interaction was not statistically significant, one genotype (line 53) was found to be more sensitive to low irrigation treatments. Two RNAseq studies were simultaneously conducted in IL and the USA to characterize expression changes that accompany shell ("source") and seed ("sink") biogenesis in peanut. Both studies showed that SF and PF processes are very dynamic and undergo very rapid change in the accumulation of RNA, nutrients, and oil. Some genotypes differ in transcript accumulation rates, which can explain their difference in SF and PF potential; like cvHanoch that was found to be more enriched than line 53 in processes involving the generation of metabolites and energy at the beginning of seed development. Interestingly, an opposite situation was found in pericarp development, wherein rapid cell wall maturation processes were up-regulated in line 53. Although no significant effect was found for the irrigation level on seed transcriptome in general, and particularly on subgenomic assignment (that was found almost comparable to a 1:1 for A- and B- subgenomes), more specific homoeologous expression changes associated with particular biosynthesis pathways were found. For example, some significant A- and B- biases were observed in particular parts of the oil related gene expression network and several candidate genes with potential influence on oil content and SF were further examined. Substation achievement of the current program was the development and application of new SNP detection and mapping methods for peanut. Two major efforts on this direction were performed. In IL, a GBS approach was developed to map pod quality traits on Hanoch X 53 F2/F3 generations. Although the GBS approach was found to be less effective for our genetic system, it still succeeded to find significant mapping locations for several traits like testa color (linkage A10), number of seeds/pods (A5) and pod wart resistance (B7). In the USA, a SNP array was developed and applied for peanut, which is based on whole genome re-sequencing of 20 genotypes. This chip was used to map pod quality related traits in a Tifrunner x NC3033 RIL population. It was phenotyped for three years, including a new x-ray method to phenotype seed-fill and seed density. The total map size was 1229.7 cM with 1320 markers assigned. Based on this linkage map, 21 QTLs were identified for the traits 16/64 weight, kernel percentage, seed and pod weight, double pod and pod area. Collectively, this research serves as the first fundamental effort in peanut for understanding the PF and SF components, as a whole, and as influenced by the irrigation level. Results of the proposed study will also generate information and materials that will benefit peanut breeding by facilitating selection for reduced linkage drag during introgression of disease resistance traits into elite cultivars. BARD Report - Project4540 Page 2 of 10
7
Chamovitz, Daniel, and Albrecht Von Arnim. Translational regulation and light signal transduction in plants: the link between eIF3 and the COP9 signalosome. United States Department of Agriculture, November 2006. http://dx.doi.org/10.32747/2006.7696515.bard.
Full textAbstract:
The COP9 signalosome (CSN) is an eight-subunit protein complex that is highly conserved among eukaryotes. Genetic analysis of the signalosome in the plant model species Arabidopsis thaliana has shown that the signalosome is a repressor of light dependent seedling development as mutant Arabidopsis seedlings that lack this complex develop in complete darkness as if exposed to light. These mutant plants die following the seedling stage, even when exposed to light, indicating that the COP9 signalosome also has a central role in the regulation of normal photomorphogenic development. The biochemical mode of action of the signalosome and its position in eukaryotic cell signaling pathways is a matter of controversy and ongoing investigation, and recent results place the CSN at the juncture of kinase signaling pathways and ubiquitin-mediated protein degradation. We have shown that one of the many CSN functions may relate to the regulation of translation through the interaction of the CSN with its related complex, eukaryotic initiation factor (eIF3). While we have established a physical connection between eIF3 subunits and CSN subunits, the physiological and developmental significance of this interaction is still unknown. In an effort to understand the biochemical activity of the signalosome, and its role in regulating translation, we originally proposed to dissect the contribution of "h" subunit of eIF3 (eIF3h) along the following specific aims: (i) Isolation and phenotypic characterization of an Arabidopsis loss-of-function allele for eIF3h from insertional mutagenesis libraries; (ii) Creation of designed gain and loss of function alleles for eIF3h on the basis of its nucleocytoplasmic distribution and its yeast-two-hybrid interactions with other eIF3 and signalosome partner proteins; (iii) Determining the contribution of eIF3h and its interaction with the signalosome by expressing specific mutants of eIF3h in the eIF3h- loss-of function background. During the course of the research, these goals were modified to include examining the genetic interaction between csn and eif3h mutations. More importantly, we extended our effort toward the genetic analysis of mutations in the eIF3e subunit, which also interacts with the CSN. Through the course of this research program we have made several critical scientific discoveries, all concerned with the apparent diametrically opposed roles of eIF3h and eIF3e. We showed that: 1) While eIF3e is essential for growth and development, eIF3h is not essential for growth or basal translation; 2) While eIF3e has a negative role in translational regulation, eIF3h is positively required for efficient translation of transcripts with complex 5' UTR sequences; 3) Over-accumulation of eIF3e and loss-of-function of eIF3h both lead to cop phenotypes in dark-grown seedlings. These results were published in one publication (Kim et al., Plant Cell 2004) and in a second manuscript currently in revision for Embo J. Are results have led to a paradigm shift in translation research – eIF3 is now viewed in all systems as a dynamic entity that contains regulatory subuits that affect translational efficiency. In the long-term agronomic outlook, the proposed research has implications that may be far reaching. Many important plant processes, including developmental and physiological responses to light, abiotic stress, photosynthate, and hormones operate in part by modulating protein translation [23, 24, 40, 75]. Translational regulation is slowly coming of age as a mechanism for regulating foreign gene expression in plants, beginning with translational enhancers [84, 85] and more recently, coordinating the expression of multiple transgenes using internal ribosome entry sites. Our contribution to understanding the molecular mode of action of a protein complex as fundamental as eIF3 is likely to lead to advances that will be applicable in the foreseeable future.
8
Monetary Policy Report - January 2022. Banco de la República, March 2022. http://dx.doi.org/10.32468/inf-pol-mont-eng.tr1-2022.
Full textAbstract:
Macroeconomic summary Several factors contributed to an increase in projected inflation on the forecast horizon, keeping it above the target rate. These included inflation in December that surpassed expectations (5.62%), indexation to higher inflation rates for various baskets in the consumer price index (CPI), a significant real increase in the legal minimum wage, persistent external and domestic inflationary supply shocks, and heightened exchange rate pressures. The CPI for foods was affected by the persistence of external and domestic supply shocks and was the most significant contributor to unexpectedly high inflation in the fourth quarter. Price adjustments for fuels and certain utilities can explain the acceleration in inflation for regulated items, which was more significant than anticipated. Prices in the CPI for goods excluding food and regulated items also rose more than expected. This was partly due to a smaller effect on prices from the national government’s VAT-free day than anticipated by the technical staff and more persistent external pressures, including via peso depreciation. By contrast, the CPI for services excluding food and regulated items accelerated less than expected, partly reflecting strong competition in the communications sector. This was the only major CPI basket for which prices increased below the target inflation rate. The technical staff revised its inflation forecast upward in response to certain external shocks (prices, costs, and depreciation) and domestic shocks (e.g., on meat products) that were stronger and more persistent than anticipated in the previous report. Observed inflation and a real increase in the legal minimum wage also exceeded expectations, which would boost inflation by affecting price indexation, labor costs, and inflation expectations. The technical staff now expects year-end headline inflation of 4.3% in 2022 and 3.4% in 2023; core inflation is projected to be 4.5% and 3.6%, respectively. These forecasts consider the lapse of certain price relief measures associated with the COVID-19 health emergency, which would contribute to temporarily keeping inflation above the target on the forecast horizon. It is important to note that these estimates continue to contain a significant degree of uncertainty, mainly related to the development of external and domestic supply shocks and their ultimate effects on prices. Other contributing factors include high price volatility and measurement uncertainty related to the extension of Colombia’s health emergency and tax relief measures (such as the VAT-free days) associated with the Social Investment Law (Ley de Inversión Social). The as-yet uncertain magnitude of the effects of a recent real increase in the legal minimum wage (that was high by historical standards) and high observed and expected inflation, are additional factors weighing on the overall uncertainty of the estimates in this report. The size of excess productive capacity remaining in the economy and the degree to which it is closing are also uncertain, as the evolution of the pandemic continues to represent a significant forecast risk. margin, could be less dynamic than expected. And the normalization of monetary policy in the United States could come more quickly than projected in this report, which could negatively affect international financing costs. Finally, there remains a significant degree of uncertainty related to the duration of supply chocks and the degree to which macroeconomic and political conditions could negatively affect the recovery in investment. The technical staff revised its GDP growth projection for 2022 from 4.7% to 4.3% (Graph 1.3). This revision accounts for the likelihood that a larger portion of the recent positive dynamic in private consumption would be transitory than previously expected. This estimate also contemplates less dynamic investment behavior than forecast in the previous report amid less favorable financial conditions and a highly uncertain investment environment. Third-quarter GDP growth (12.9%), which was similar to projections from the October report, and the fourth-quarter growth forecast (8.7%) reflect a positive consumption trend, which has been revised upward. This dynamic has been driven by both public and private spending. Investment growth, meanwhile, has been weaker than forecast. Available fourth-quarter data suggest that consumption spending for the period would have exceeded estimates from October, thanks to three consecutive months that included VAT-free days, a relatively low COVID-19 caseload, and mobility indicators similar to their pre-pandemic levels. By contrast, the most recently available figures on new housing developments and machinery and equipment imports suggest that investment, while continuing to rise, is growing at a slower rate than anticipated in the previous report. The trade deficit is expected to have widened, as imports would have grown at a high level and outpaced exports. Given the above, the technical staff now expects fourth-quarter economic growth of 8.7%, with overall growth for 2021 of 9.9%. Several factors should continue to contribute to output recovery in 2022, though some of these may be less significant than previously forecast. International financial conditions are expected to be less favorable, though external demand should continue to recover and terms of trade continue to increase amid higher projected oil prices. Lower unemployment rates and subsequent positive effects on household income, despite increased inflation, would also boost output recovery, as would progress in the national vaccination campaign. The technical staff expects that the conditions that have favored recent high levels of consumption would be, in large part, transitory. Consumption spending is expected to grow at a slower rate in 2022. Gross fixed capital formation (GFCF) would continue to recover, approaching its pre-pandemic level, though at a slower rate than anticipated in the previous report. This would be due to lower observed GFCF levels and the potential impact of political and fiscal uncertainty. Meanwhile, the policy interest rate would be less expansionary as the process of monetary policy normalization continues. Given the above, growth in 2022 is forecast to decelerate to 4.3% (previously 4.7%). In 2023, that figure (3.1%) is projected to converge to levels closer to the potential growth rate. In this case, excess productive capacity would be expected to tighten at a similar rate as projected in the previous report. The trade deficit would tighten more than previously projected on the forecast horizon, due to expectations of an improved export dynamic and moderation in imports. The growth forecast for 2022 considers a low basis of comparison from the first half of 2021. However, there remain significant downside risks to this forecast. The current projection does not, for example, account for any additional effects on economic activity resulting from further waves of COVID-19. High private consumption levels, which have already surpassed pre-pandemic levels by a large margin, could be less dynamic than expected. And the normalization of monetary policy in the United States could come more quickly than projected in this report, which could negatively affect international financing costs. Finally, there remains a significant degree of uncertainty related to the duration of supply chocks and the degree to which macroeconomic and political conditions could negatively affect the recovery in investment. External demand for Colombian goods and services should continue to recover amid significant global inflation pressures, high oil prices, and less favorable international financial conditions than those estimated in October. Economic activity among Colombia’s major trade partners recovered in 2021 amid countries reopening and ample international liquidity. However, that growth has been somewhat restricted by global supply chain disruptions and new outbreaks of COVID-19. The technical staff has revised its growth forecast for Colombia’s main trade partners from 6.3% to 6.9% for 2021, and from 3.4% to 3.3% for 2022; trade partner economies are expected to grow 2.6% in 2023. Colombia’s annual terms of trade increased in 2021, largely on higher oil, coffee, and coal prices. This improvement came despite increased prices for goods and services imports. The expected oil price trajectory has been revised upward, partly to supply restrictions and lagging investment in the sector that would offset reduced growth forecasts in some major economies. Elevated freight and raw materials costs and supply chain disruptions continue to affect global goods production, and have led to increases in global prices. Coupled with the recovery in global demand, this has put upward pressure on external inflation. Several emerging market economies have continued to normalize monetary policy in this context. Meanwhile, in the United States, the Federal Reserve has anticipated an end to its asset buying program. U.S. inflation in December (7.0%) was again surprisingly high and market average inflation forecasts for 2022 have increased. The Fed is expected to increase its policy rate during the first quarter of 2022, with quarterly increases anticipated over the rest of the year. For its part, Colombia’s sovereign risk premium has increased and is forecast to remain on a higher path, to levels above the 15-year-average, on the forecast horizon. This would be partly due to the effects of a less expansionary monetary policy in the United States and the accumulation of macroeconomic imbalances in Colombia. Given the above, international financial conditions are projected to be less favorable than anticipated in the October report. The increase in Colombia’s external financing costs could be more significant if upward pressures on inflation in the United States persist and monetary policy is normalized more quickly than contemplated in this report. As detailed in Section 2.3, uncertainty surrounding international financial conditions continues to be unusually high. Along with other considerations, recent concerns over the potential effects of new COVID-19 variants, the persistence of global supply chain disruptions, energy crises in certain countries, growing geopolitical tensions, and a more significant deceleration in China are all factors underlying this uncertainty. The changing macroeconomic environment toward greater inflation and unanchoring risks on inflation expectations imply a reduction in the space available for monetary policy stimulus. Recovery in domestic demand and a reduction in excess productive capacity have come in line with the technical staff’s expectations from the October report. Some upside risks to inflation have materialized, while medium-term inflation expectations have increased and are above the 3% target. Monetary policy remains expansionary. Significant global inflationary pressures and the unexpected increase in the CPI in December point to more persistent effects from recent supply shocks. Core inflation is trending upward, but remains below the 3% target. Headline and core inflation projections have increased on the forecast horizon and are above the target rate through the end of 2023. Meanwhile, the expected dynamism of domestic demand would be in line with low levels of excess productive capacity. An accumulation of macroeconomic imbalances in Colombia and the increased likelihood of a faster normalization of monetary policy in the United States would put upward pressure on sovereign risk perceptions in a more persistent manner, with implications for the exchange rate and the natural rate of interest. Persistent disruptions to international supply chains, a high real increase in the legal minimum wage, and the indexation of various baskets in the CPI to higher inflation rates could affect price expectations and push inflation above the target more persistently. These factors suggest that the space to maintain monetary stimulus has continued to diminish, though monetary policy remains expansionary. 1.2 Monetary policy decision Banco de la República’s board of directors (BDBR) in its meetings in December 2021 and January 2022 voted to continue normalizing monetary policy. The BDBR voted by a majority in these two meetings to increase the benchmark interest rate by 50 and 100 basis points, respectively, bringing the policy rate to 4.0%.