Academic literature on the topic 'Cortex m-series'
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Journal articles on the topic "Cortex m-series"
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Vaculik, L., and M. Penhaker. "High Efficiency Code Optimization in ARM Cortex-M Series Processor." IFAC Proceedings Volumes 46, no. 28 (2013): 312–15. http://dx.doi.org/10.3182/20130925-3-cz-3023.00109.
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Eastwood, Sharon L., Nigel J. Cairns, and Paul J. Harrison. "Synaptophysin gene expression in schizophrenia." British Journal of Psychiatry 176, no. 3 (2000): 236–42. http://dx.doi.org/10.1192/bjp.176.3.236.
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BackgroundDecreased expression of proteins such as synaptophysin in the hippocampus and prefrontal cortex in schizophrenia is suggestive of synaptic pathology. However, the overall profile of changes is unclear.AimsTo investigate synaptophysin gene expression in the cerebral cortex in schizophrenia.MethodThe dorsolateral prefrontal (Brodmann area [BA] 9/46), anterior cingulate (BA 24), superior temporal (BA 22) and occipital (BA 17) cortex were studied in two series of brains, totalling 19 cases and 19 controls. Synaptophysin was measured by immunoautoradiography and immunoblotting. Synaptophysin messenger RNA (m RNA) was measured using in situ hybridisation.ResultsSynaptophysin was unchanged in schizophrenia, except for a reduction in BA 17 of one brain series. Synaptophysin mRNA was decreased in BA 17, and in BA 22 in the women with schizophrenia. No alterations were seen in BA 9/46.ConclusionsSynaptophysin expression is decreased in some cortical areas in schizophrenia. The alterations affect the mRNA more than the protein, and have an unexpected regional distribution. The characteristics of the implied synaptic pathology remain to be determined.
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Wooten, Dustin W., Ansel T. Hillmer, Jeffrey M. Moirano, et al. "Measurement of 5-HT1A Receptor Density and in-vivo Binding Parameters of [18F]mefway in the Nonhuman Primate." Journal of Cerebral Blood Flow & Metabolism 32, no. 8 (2012): 1546–58. http://dx.doi.org/10.1038/jcbfm.2012.43.
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The goal of this work was to characterize the in-vivo behavior of [18F]mefway as a suitable positron emission tomography (PET) radiotracer for the assay of 5-hydroxytryptamine1A (5-HT1A) receptor density ( Bmax). Six rhesus monkeys were studied using a multiple-injection (M-I) protocol consisting of three sequential bolus injections of [18F]mefway. Injection times and amounts of unlabeled mefway were optimized for the precise measurement of Bmax and specific binding parameters koff and kon for estimation of apparent KD. The PET time series were acquired for 180 minutes with arterial sampling performed throughout. Compartmental analysis using the arterial input function was performed to obtain estimates for K1, k2, koff, Bmax, and KDapp in the cerebral cortex and raphe nuclei (RN) using a model that accounted for nontracer doses of mefway. Averaged over subjects, highest binding was seen in the mesial temporal and dorsal anterior cingulate cortices with Bmax values of 42±8 and 36±8 pmol/mL, respectively, and lower values in the superior temporal cortex, RN, and parietal cortex of 24±4, 19±4, and 13±2 pmol/mL, respectively. The KDapp of mefway for the 5-HT1A receptor sites was 4.3±1.3 nmol/L. In conclusion, these results show that M-I [18F]mefway PET experiments can be used for the in-vivo measurement of 5-HT1A receptor density.
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Liu, Qin, Antonio Ulloa, and Barry Horwitz. "Using a Large-scale Neural Model of Cortical Object Processing to Investigate the Neural Substrate for Managing Multiple Items in Short-term Memory." Journal of Cognitive Neuroscience 29, no. 11 (2017): 1860–76. http://dx.doi.org/10.1162/jocn_a_01163.
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Many cognitive and computational models have been proposed to help understand working memory. In this article, we present a simulation study of cortical processing of visual objects during several working memory tasks using an extended version of a previously constructed large-scale neural model [Tagamets, M. A., & Horwitz, B. Integrating electrophysiological and anatomical experimental data to create a large-scale model that simulates a delayed match-to-sample human brain imaging study. Cerebral Cortex, 8, 310–320, 1998]. The original model consisted of arrays of Wilson–Cowan type of neuronal populations representing primary and secondary visual cortices, inferotemporal (IT) cortex, and pFC. We added a module representing entorhinal cortex, which functions as a gating module. We successfully implemented multiple working memory tasks using the same model and produced neuronal patterns in visual cortex, IT cortex, and pFC that match experimental findings. These working memory tasks can include distractor stimuli or can require that multiple items be retained in mind during a delay period (Sternberg's task). Besides electrophysiology data and behavioral data, we also generated fMRI BOLD time series from our simulation. Our results support the involvement of IT cortex in working memory maintenance and suggest the cortical architecture underlying the neural mechanisms mediating particular working memory tasks. Furthermore, we noticed that, during simulations of memorizing a list of objects, the first and last items in the sequence were recalled best, which may implicate the neural mechanism behind this important psychological effect (i.e., the primacy and recency effect).
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Widden, Paul. "The morphology of vesicular – arbuscular mycorrhizae in Clintonia borealis and Medeola virginiana." Canadian Journal of Botany 74, no. 5 (1996): 679–85. http://dx.doi.org/10.1139/b96-086.
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During a survey of the vesicular–arbuscular mycorrhizal (VAM) associations of forest herbs in a deciduous forest in the southern Laurentian mountains in Quebec, two liliaceous species, Clintonia borealis and Medeola virginiana, revealed very distinctive morphology. In both species, once the epidermis was penetrated, the fungus spread towards the centre of the root via intracellular hyphae until the innermost layer of the cortex was reached, at which point the fungus spread laterally and tangentially through the cortical cells adjacent to the endodermis via a series of banana-shaped projections (bobbits). These eventually differentiated into the arbuscules and the VAM might spread from this inner cortical layer back into the outer cortical layers. In C. borealis, the hyphae coiled in the cortex, and vesicles were formed in the upper cortical cells. In M. virginiana, no coiling took place, but extensive diverticulae were produced by the intracellular hyphae in the cortical cells, close to their point of exit, and vesicles were produced in the inner cortex as swellings from the bobbits. These two mycorrhizae have some similarities to one in Colchicum autumnale described by I. Gallaud (1905. Rev. Gen. Bot. 17). Keywords: vesicular–arbuscular mycorrhizae, Clintonia borealis, Medeola virginiana, Liliaceae, morphology.
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Paudyal, Arjun, Hans Degens, Guus C. Baan, et al. "Changes in muscle–tendon unit length–force characteristics following experimentally induced photothrombotic stroke cannot be explained by changes in muscle belly structure." European Journal of Applied Physiology 121, no. 9 (2021): 2509–19. http://dx.doi.org/10.1007/s00421-021-04729-x.
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Abstract Purpose The aim of this study was to assess the effects of experimentally induced photothrombotic stroke on structural and mechanical properties of rat m. flexor carpi ulnaris. Methods Two groups of Young-adult male Sprague–Dawley rats were measured: stroke (n = 9) and control (n = 7). Photothrombotic stroke was induced in the forelimb region of the primary sensorimotor cortex. Four weeks later, muscle–tendon unit and muscle belly length–force characteristics of the m. flexor carpi ulnaris, mechanical interaction with the neighbouring m. palmaris longus, the number of sarcomeres in series within muscle fibres, and the physiological cross-sectional area were measured. Results Stroke resulted in higher force and stiffness of the m. flexor carpi ulnaris at optimum muscle–tendon unit length, but only for the passive conditions. Stroke did not alter the length–force characteristics of m. flexor carpi ulnaris muscle belly, morphological characteristics, and the extent of mechanical interaction with m. palmaris longus muscle. Conclusion The higher passive force and passive stiffness at the muscle–tendon unit level in the absence of changes in structural and mechanical characteristics of the muscle belly indicates that the experimentally induced stroke resulted in an increased stiffness of the tendon.
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Che, Zhi-Ping, Jin-Ming Yang, Di Sun, et al. "Combinatorial Synthesis of A Series of Paeonol-based Phenylsulfonyl hydrazone Derivatives as Insecticidal Agents." Combinatorial Chemistry & High Throughput Screening 23, no. 3 (2020): 232–38. http://dx.doi.org/10.2174/1386207323666200127121129.
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Background: Plant secondary metabolites play an essential role in the discovery of novel insecticide due to their unique sources and potential target sites. Paeonol, the main phenolic components in Moutan Cortex, is recognized as a safe and potent botanical insecticide to many insects. The structural modification of paeonol in this study into phenylsulfonylhydrazone derivatives is proved an effective approach for the development of novel insecticides, those derivatives being more toxic than paeonol. However, there have been no reports on the insecticidal activity of paeonol-based phenylsulfonylhydrazone derivatives in controlling Mythimna separata. Methods: We have been working to discover biorational natural products-based insecticides. Twelve novel paeonol-based phenylsulfonylhydrazone derivatives have been successfully prepared by structural modification of paeonol, and the insecticidal activity against M. separata by the leafdipping method at the concentration of 1 mg/mL has been evaluated. Results: Insecticidal activity revealed that out of 12 title compounds, derivatives 5c and 5f displayed the best against M. separate with the FMR both of 53.6% than toosendanin (FMR = 50.0%). Conclusion: The results suggested that for the paeonol-based phenylsulfonylhydrazone series derivatives, the proper substituent of arylsulfonyl R at the hydroxyl position of paeonol was very important for their insecticidal activity. These preliminary results will pave the way for further modification of paeonol in the development of potential new insecticides.
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Calvert, Gemma A., and Ruth Campbell. "Reading Speech from Still and Moving Faces: The Neural Substrates of Visible Speech." Journal of Cognitive Neuroscience 15, no. 1 (2003): 57–70. http://dx.doi.org/10.1162/089892903321107828.
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Speech is perceived both by ear and by eye. Unlike heard speech, some seen speech gestures can be captured in stilled image sequences. Previous studies have shown that in hearing people, natural time-varying silent seen speech can access the auditory cortex (left superior temporal regions). Using functional magnetic resonance imaging (fMRI), the present study explored the extent to which this circuitry was activated when seen speech was deprived of its time-varying characteristics. In the scanner, hearing participants were instructed to look for a prespecified visible speech target sequence (“voo” or “ahv”) among other monosyllables. In one condition, the image sequence comprised a series of stilled key frames showing apical gestures (e.g., separate frames for “v” and “oo” [from the target] or “ee” and “m” [i.e., from nontarget syllables]). In the other condition, natural speech movement of the same overall segment duration was seen. In contrast to a baseline condition in which the letter “V” was superimposed on a resting face, stilled speech face images generated activation in posterior cortical regions associated with the perception of biological movement, despite the lack of apparent movement in the speech image sequence. Activation was also detected in traditional speech-processing regions including the left inferior frontal (Broca's) area, left superior temporal sulcus (STS), and left supramarginal gyrus (the dorsal aspect of Wernicke's area). Stilled speech sequences also generated activation in the ventral premotor cortex and anterior inferior parietal sulcus bilaterally. Moving faces generated significantly greater cortical activation than stilled face sequences, and in similar regions. However, a number of differences between stilled and moving speech were also observed. In the visual cortex, stilled faces generated relatively more activation in primary visual regions (V1/V2), while visual movement areas (V5/MT+) were activated to a greater extent by moving faces. Cortical regions activated more by naturally moving speaking faces included the auditory cortex (Brodmann's Areas 41/42; lateral parts of Heschl's gyrus) and the left STS and inferior frontal gyrus. Seen speech with normal time-varying characteristics appears to have preferential access to “purely” auditory processing regions specialized for language, possibly via acquired dynamic audiovisual integration mechanisms in STS. When seen speech lacks natural time-varying characteristics, access to speech-processing systems in the left temporal lobe may be achieved predominantly via action-based speech representations, realized in the ventral premotor cortex.
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Williams, Brian J., Dima Suki, Benjamin D. Fox, et al. "Stereotactic radiosurgery for metastatic brain tumors: a comprehensive review of complications." Journal of Neurosurgery 111, no. 3 (2009): 439–48. http://dx.doi.org/10.3171/2008.11.jns08984.
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Object Stereotactic radiosurgery (SRS) is commonly used to treat brain metastases. Complications associated with this treatment are underreported. The authors reviewed a large series of patients who underwent SRS for brain metastases to identify complications and factors predicting their occurrence. Methods Prospectively collected clinical data from 273 patients undergoing SRS for 1 or 2 brain metastases at The University of Texas M. D. Anderson Cancer Center between June 1993 and December 2004 were reviewed. Patients who had received prior treatment for their tumor, including whole-brain radiation, SRS, or surgery, were excluded from the study. Data on adverse neurological and nonneurological outcomes following treatment were collected. Results Three hundred sixteen lesions were treated. Complications were associated with 127 (40%) of 316 treated lesions. New neurological complications were associated with 101 (32%) of 316 lesions. The onset of seizure was the most common complication, occurring in 41 (13%) of 316 SRS cases. On multivariate analysis, progressing primary cancer (hazard ratio [HR] = 2.4, 95% CI 1.6–3.6, p < 0.001), tumor location in eloquent cortex (HR = 2.3, 95% CI 1.6–3.4, p < 0.001), and lower (< 15 Gy) SRS dose (HR = 2.1, 95% CI 1.1–4.2, p = 0.04) were significantly associated with new complications. On multivariate analysis, a tumor location in the eloquent cortex (HR = 2.5, 95% CI 1.6–3.8, p < 0.001) and progressing primary cancer (HR = 1.6, 95% CI 1.1–2.5, p = 0.03) were significantly associated with new neurological complications. Conclusions The authors showed that new neurological and nonneurological complications were associated with 40% of SRS treatments for brain metastases. Patients with lesions in functional brain regions have a significantly increased risk of treatment-related complications.
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Nahon, P., G. Coffe, H. Guyader, et al. "Identification of the epiplasmins, a new set of cortical proteins of the membrane cytoskeleton in Paramecium." Journal of Cell Science 104, no. 4 (1993): 975–90. http://dx.doi.org/10.1242/jcs.104.4.975.
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In most ciliates, the epiplasm, a superficial cytoskeletal layer of variable thickness, both surrounds basal bodies and interacts tightly with adjacent membrane networks; it constitutes the predominant structure in Paramecium cell ghosts. Previous indirect data suggested several cortical proteins as potential constituents of the epiplasm. New sharp monoclonal antibodies presented in this paper, positive both on immunotransfers and in immunocytochemical tests carried out on permeabilized cells and ultrathin sections, definitively identify the epiplasmins: a set of about twenty protein bands ranging from 45 to 33 kDa and making up the bulk of the epiplasmic layer. The complete epiplasmin pattern characterized from gradient-purified cortex is also present in unfractionated whole cells, confirming that the pattern is not generated artifactually. Comparative one-step extractions, performed either in 1 M KI or in 4 M urea, solubilize the epiplasmins as a whole, indicating that all of them share very similar biochemical properties. Two-dimensional electrophoresis shows the great complexity of this epiplasmin group. Epiplasmin solubilization properties are discussed with respect to other models of membrane-cytoskeleton interaction developed among protists and metazoans and also to intermediate filaments, specially lamins. Immunofluorescent labelling combined with confocal microscopy permits a more detailed study of epiplasm formation at the level of the fission furrow, with new insights into two successive steps of epiplasm growth. A first series of interspecific reactions has been carried out with one of the anti- epiplasmin antibodies, yielding results which are discussed in an evolutionary framework.
Dissertations / Theses on the topic "Cortex m-series"
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Fredriksson, Tomas, and Rickard Svensson. "Analysis of machine learning for human motion pattern recognition on embedded devices." Thesis, KTH, Mekatronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-246087.
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With an increased amount of connected devices and the recent surge of artificial intelligence, the two technologies need more attention to fully bloom as a useful tool for creating new and exciting products. As machine learning traditionally is implemented on computers and online servers this thesis explores the possibility to extend machine learning to an embedded environment. This evaluation of existing machine learning in embedded systems with limited processing capa-bilities has been carried out in the specific context of an application involving classification of basic human movements. Previous research and implementations indicate that it is possible with some limitations, this thesis aims to answer which hardware limitation is affecting clas-sification and what classification accuracy the system can reach on an embedded device. The tests included human motion data from an existing dataset and included four different machine learning algorithms on three devices. Support Vector Machine (SVM) are found to be performing best com-pared to CART, Random Forest and AdaBoost. It reached a classification accuracy of 84,69% between six different included motions with a clas-sification time of 16,88 ms per classification on a Cortex M4 processor. This is the same classification accuracy as the one obtained on the host computer with more computational capabilities. Other hardware and machine learning algorithm combinations had a slight decrease in clas-sification accuracy and an increase in classification time. Conclusions could be drawn that memory on the embedded device affect which al-gorithms could be run and the complexity of data that can be extracted in form of features. Processing speed is mostly affecting classification time. Additionally the performance of the machine learning system is connected to the type of data that is to be observed, which means that the performance of different setups differ depending on the use case.<br>Antalet uppkopplade enheter ökar och det senaste uppsvinget av ar-tificiell intelligens driver forskningen framåt till att kombinera de två teknologierna för att både förbättra existerande produkter och utveckla nya. Maskininlärning är traditionellt sett implementerat på kraftfulla system så därför undersöker den här masteruppsatsen potentialen i att utvidga maskininlärning till att köras på inbyggda system. Den här undersökningen av existerande maskinlärningsalgoritmer, implemen-terade på begränsad hårdvara, har utförts med fokus på att klassificera grundläggande mänskliga rörelser. Tidigare forskning och implemen-tation visar på att det ska vara möjligt med vissa begränsningar. Den här uppsatsen vill svara på vilken hårvarubegränsning som påverkar klassificering mest samt vilken klassificeringsgrad systemet kan nå på den begränsande hårdvaran. Testerna inkluderade mänsklig rörelsedata från ett existerande dataset och inkluderade fyra olika maskininlärningsalgoritmer på tre olika system. SVM presterade bäst i jämförelse med CART, Random Forest och AdaBoost. Den nådde en klassifikationsgrad på 84,69% på de sex inkluderade rörelsetyperna med en klassifikationstid på 16,88 ms per klassificering på en Cortex M processor. Detta är samma klassifikations-grad som en vanlig persondator når med betydligt mer beräknings-resurserresurser. Andra hårdvaru- och algoritm-kombinationer visar en liten minskning i klassificeringsgrad och ökning i klassificeringstid. Slutsatser kan dras att minnet på det inbyggda systemet påverkar vilka algoritmer som kunde köras samt komplexiteten i datan som kunde extraheras i form av attribut (features). Processeringshastighet påverkar mest klassificeringstid. Slutligen är prestandan för maskininlärningsy-stemet bunden till typen av data som ska klassificeras, vilket betyder att olika uppsättningar av algoritmer och hårdvara påverkar prestandan olika beroende på användningsområde.
Books on the topic "Cortex m-series"
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Hank, Karsten, Frank Schulz-Nieswandt, Michael Wagner, and Susanne Zank, eds. Alternsforschung. Nomos Verlagsgesellschaft mbH & Co. KG, 2019. http://dx.doi.org/10.5771/9783845276687.
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This handbook aims to provide an overview of knowledge about age and ageing in ‘Western’ societies at the beginning of the 21st century, which is intended to be equally suitable for research and practice. It focuses on relevant contributions from the social and behavioural sciences and their access to selected aspects of age and ageing. Its main topics can be described as quintessential core subjects, e.g. theories of ageing, socio-economic situation and inequalities, mental and physical health, social networks and social participation. These are supplemented by contributions on often marginalised topics and ‘emerging topics’ such as very old age, experiences of violence and delinquency, sexuality, and the spirituality and ethics of ageing. Finally, a series of topics relevant to everyday life and research practice (e.g. age and technology and data collection among the elderly) form a third central component of the book. With contributions by Heike Baranzke | Hermann Brandenburg | Susanne Brose | Josef Ehmer | Yvonne Eisenmann | Lea Ellwardt | Marcel Erlinghagen | Uwe Fachinger | Luise Geithner | Thomas Görgen | Bernadette Groebe | Helen Güther | Hans Gutzmann | Karsten Hank | Peter Häussermann | Rolf G. Heinze | Kira Hower | Anna Janhsen | Roman Kaspar | Daniela Klaus | Lars-Oliver Klotz | Franziska Kunz | Lisa Luft | Katharina Mahne | Michael Neise | Frank Oswald | Johannes Pantel | Susanne Penger | Holger Pfaff | M. Christina Polidori | Christian Rietz | Charlotte Şahin | Anna Schlomann | Holger Schmidt | Laura Schmidt | Wiebke Schmitz | Katrin Schneiders | Frank Schulz-Nieswandt | Andreas Simm | Julia Simonson | Anja Steinbach | Stephanie Stock | Julia Strupp | Clemens Tesch-Römer | Claudia Vogel | Raymond Voltz | Michael Wagner | Hans-Werner Wahl | Inka Wilhelm | Christiane Woopen | Susanne Zank
Conference papers on the topic "Cortex m-series"
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Mei, Joseph S., Lawrence J. Shadle, Paul Yue, and Esmail R. Monazam. "Hydrodynamics of a Transport Reactor Operating in Dense Suspension Upflow Conditions for Coal Combustion Applications." In 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78088.
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A series of experiments were conducted in the 0.3-meter diameter, 15.45-m high cold flow circulating fluid bed (CFB) test facility at the National Energy Technology Laboratory (NETL) of the U. S. Department of Energy. Operation of the CFB demonstrated that high density conditions can be achieved throughout the entire riser with sufficiently high solid fluxes in a riser taller than what has been previously reported in the literature. Tests were conducted on Geldart type B, 60 μm diameter, glass beads at two different gas velocities (5.1 and 7.8 m/s). The riser’s axial solids fraction profile provided distinct characteristics that enabled us to differentiate between dense suspension upflow (DSU) and core annular flow regimes. The apparent solids holdup in the riser exceeded 7% when operating in DSU. A fiber optic probe was used to measure particle velocities near the wall 8.5 m above the solids entry. These measurements did not always record upward particle velocities when in DSU conditions. A number of possible reasons are identified and discussed. Solid fluxes greater than 250 kg/m2-s for 5.1 m/s and 350 kg/m2-s at 7.8 m/s appeared to be sufficient to achieve DSU conditions. The trend in the measured particle velocities near the wall was also consistent with these transitions. The transition from core annular conditions to DSU operations depended upon both gas velocity and solids flux and was in good agreement with an existing correlation found in the literature.
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Oh, Chang H., and Eung S. Kim. "Validations of CFD Code for Density-Gradient Driven Air Ingress Stratified Flow." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29807.
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Air ingress into a very high temperature gas-cooled reactor (VHTR) is an important phenomenon to consider because the air oxidizes the reactor core and lower plenum where the graphite structure supports the core region in the gas turbine modular helium reactor (GT-MHR) design, thus jeopardizing the reactor’s safety. Validating the computational fluid dynamics (CFD) code used to analyze the air ingress phenomena is therefore an essential part of the safety analysis and the ultimate computation required for licensing. An experimental data set collected by ETH Zurich on a lock exchange experiment (Grobelbauser et al., Lowe et al. 2002; Lowe et al. 2005; and Shin et al. 2004) was selected for the validation. The experiment was based on a series of lock exchange flows with gases of different density ratios varying from 0.046 to 0.9 in a closed channel of a square cross-section. The focus was on the quantitative measurement of front velocities of the gravity current flows. The experiment results cover the full range of gas intrusions—heavy as well as light—for the gravity current flows in the lock exchange situations. FLUENT CFD code (ANSYS Fluent 2008) was used. The calculated results showed very good agreement with the experimental data. A number of tables and comparison plots are included to summarize the estimated current speeds. The current speed obtained by experimental data was 1.25 m/s and that of the simulation was 1.19 m/s. This result indicates that the deviation of the simulation is only 4.8% that of the experimental data.
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Teigen, Sigurd Henrik, Joakim K. Lindvall, Ilija Samardzija, and Roar I. Hansen. "Station-Keeping Trials in Ice: Ice and Metocean Conditions." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-78620.
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In March 2017, Statoil performed station-keeping trials in drifting ice in the Bay of Bothnia with the two anchor handling tug supply vessels Magne Viking and Tor Viking. During the trials observations of ice and metocean conditions were performed via a range of platforms and techniques. The purpose of the observations was to document the main physical parameters affecting the station-keeping vessel and ice management vessel, as well as giving tactical information on ice conditions and input to simultaneous numerical simulations. Measurements of meteorological parameters (wind speed, wind direction, air temperature, etc.) were done from the two vessels and supplemented with manual observations. Ice drift was independently measured by drifting ice trackers and ADCPs (also measuring ocean current) moored on the sea bed. Measurements of ice thickness were carried out with moored Ice Profiling Sensors (IPSs) and manual ice core samples, which were also analyzed for salinity and temperature profiles. The IPS ice thickness data was later processed together with the ice drift to provide 2D spatial data. The deepest ice ridge keels ranged from 5.4 m at the site with the most benign ice conditions to 10.9 m at the most severe site. Ridge frequency also increased from 2 ridges km−1 to 16 ridges km−1 at the most severe site (given a keel threshold of 3 m). In the present study, statistical summaries of the different time series collected at the sites of the station-keeping trials are presented, highlighting the variability in the ice conditions. Using the vessel tracks and overall drift of the broken channels, ice thickness and drift measurements are classified as being inside or outside the managed ice zone.
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Rahm, Michael, and Franz Evegren. "Structural Fire Integrity Testing of Lightweight Structures." In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54418.
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To reduce environmental impact and to manage weight in shipping and offshore, lightweight structures are becoming increasingly important. A critical issue for loadbearing structures is their structural fire integrity. It is generally evaluated by loaded furnace fire resistance tests based on ISO 834. As part of the EU project BESST, a series of such tests were performed with typical lightweight fiber reinforced polymer (FRP) composite sandwich structures. The purpose was to determine whether structural fire integrity is sensitive to the design load, design method and safety factor against buckling. In particular was examined whether the temperature at the interface between the exposed laminate and the core is critical for structural integrity and how it depends on the applied loading. Independence of the applied load would make performance solely a matter of heat transfer, which would significantly reduce necessary testing. The tests were carried out with starting point in an insulated sandwich panel system, certified as a 60 minute Fire Resisting Division (FRD-60) for high-speed craft in accordance with the Fire Test Procedures (FTP) Code. The structure consisted of 1.3 mm glass fiber reinforced polyester laminates surrounding a cross linked PVC foam core called Divinycell H80 (80 kg/m3). It was constructed for a 7 kN/m design load, which is the loading applied in the FTP Code furnace test for high-speed craft. Hence, with a conventional safety factor against buckling of 2.5 it was designed to resist a critical load of 17.4 kN/m. With basis in this design, tests were performed with structures where the thickness of the laminates or core had been altered and with adjusted safety factor against the applied loading. In addition, a test was performed with a stiffened panel. Firstly it was noted that 60 minutes of fire resistance was not achieved in most of the tests, which was a consequence of an alteration in the FTP Code test procedures. The FRD-60 structure used as starting point was certified before the 2010 edition of the FTP Code was ratified. This harmonized the test procedure between laboratories and gave a slightly tougher temperature development than when the structure was certified. However, the test results are still valid and show a small variation in the time to failure in the tests with unstiffened sandwich structures, ranging between 51 and 58.5 minutes. Changing the safety factor from 2.5 to 1.5 resulted in a relatively small decrease in time to failure of 3 minutes. The stiffened test showed that structural resistance is better achieved by use of stiffeners than by thick laminates. Furthermore, applying this as a design principle and using a safety factor of 2.5 leaves a test variation between 55 and 58.5 minutes. The temperature at the exposed laminate-core interface was quite similar in the tests at the time of failure. This excludes the test when the laminate thickness was increased as a measure for structural improvement. In conclusion, the test series shows that fire resistance bulkhead testing of insulated FRP composite panels can be simplified and does not have to be performed with varying design loads. To achieve conservative evaluation, a design concept should be evaluated by testing the panel designed for the highest applicable load level, not by testing a weak panel at 7 kN/m loading. This applies to non-stiffened solutions.
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Vieira, R. E., M. Parsi, C. F. Torres, et al. "Experimental Study of Vertical Gas-Liquid Pipe Flow for Annular and Liquid Loading Conditions Using Dual Wire-Mesh Sensors." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21849.
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In gas well production, liquid is produced in two forms, droplets entrained in the gas core and liquid film flowing on the tubing wall. For most of the gas well life cycle, the predominant flow pattern is annular flow. As gas wells mature, the produced gas flow rate reduces decreasing the liquid carrying capability initiating the condition where the liquid film is unstable and flow pattern changes from fully co-current annular flow to partially co-current annular flow. The measurement and visualization of annular flow and liquid loading characteristics is of great importance from a technical point of view for process control or from a theoretical point of view for the improvement and validation of current modeling approaches. In this experimental investigation, a Wire-Mesh technique based on conductance measurements was applied to enhance the understanding of the air-water flow in vertical pipes. The flow test section consisting of a 76 mm ID pipe, 18 m long, was employed to generate annular flow and liquid loading at low pressure conditions. A 16×16 wire configuration sensor is used to determine the void fraction within the cross-section of the pipe. Data sets were collected with a sampling frequency of 10,000 Hz. Physical flow parameters were extracted based on processed raw measured data obtained by the sensors using signal processing. In this work, the principle of Wire-Mesh Sensors and the methodology of flow parameter extraction are described. From the obtained raw data, time series of void fraction, mean local void fraction distribution, characteristic frequencies and structure velocities are determined for different liquid and gas superficial velocities that ranged from 0.005 to 0.1 m/s and from 10 to 40 m/s, respectively. In order to investigate dependence of liquid loading phenomenon on viscosity, three different liquid viscosities were used. Results from the Wire-Mesh Sensors are compared with results obtained from previous experimental work using Quick Closing Valves and existing modeling approaches available in the literature.
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Kisselev, Arcadii E., Valerii F. Strizhov, Alexander D. Vasiliev, Vladimir I. Nalivayev, and Nikolay Ya Parshin. "Modeling of Thermal Hydraulics Features of Top Water Reflood Experiment PARAMETER-SF3 Using SOCRAT/V2 Code." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75516.
Full textAbstract:
The PARAMETER-SF3 test conditions simulated a severe LOCA (Loss of Coolant Accident) nuclear power plant sequence in which the overheated up to 1700÷2300K core would be reflooded from the top and the bottom in occasion of ECCS (Emergency Core Cooling System) recovery. The test was successfully conducted at the NPO “LUTCH”, Podolsk, Russia, in October 31, 2008, and was the third of four experiments of series PARAMETER-SF. PARAMETER facility of NPO “LUTCH”, Podolsk, is designed for studies of the VVER fuel assemblies behavior under conditions simulating design basis, beyond design basis and severe accidents. The test bundle was made up of 19 fuel rod simulators with a length of approximately 3.12 m (heated rod simulators) and 2.92 m (unheated rod simulator). Heating was carried out electrically using 4-mm-diameter tantalum heating elements installed in the center of the rods and surrounded by annular UO2 pellets. The rod cladding was identical to that used in VVERs: Zr1%Nb, 9.13 mm outside diameter, 0.7 mm wall thickness. After the maximum cladding temperature of about 1900K was reached in the bundle during PARAMETER-SF3 test, the top flooding was initiated. The thermal hydraulic and SFD (Severe Fuel Damage) best estimate numerical complex SOCRAT/V2 was used for the calculation of PARAMETER-SF3 experiment. The counter-current flow limitation (CCFL) model was implemented to best estimate numerical code SOCRAT/V2 developed for modeling thermal hydraulics and severe accident phenomena in a reactor. Thermal hydraulics in PARAMETER-SF3 experiment played very important role and its adequate modeling is important for the thermal analysis. The results obtained by the complex SOCRAT/V2 were compared with experimental data concerning different aspects of thermal hydraulics behavior including the CCFL phenomenon during the reflood. The temperature experimental data were found to be in a good agreement with calculated results. It is indicative of the adequacy of modeling the complicated thermo-hydraulic behavior in the PARAMETER-SF3 test.
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Vasiliev, Alexander D. "Application of Thermal Hydraulic Code SOCRAT/V2 to Top Water Reflood Experiment PARAMETER-SF3." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-10960.
Full textAbstract:
The PARAMETER-SF3 test conditions simulated a severe LOCA (Loss of Coolant Accident) nuclear power plant sequence in which the overheated up to 1700–2300K core would be reflooded from the top and the bottom in occasion of ECCS (Emergency Core Cooling System) recovery. The test was successfully conducted at the NPO “LUTCH”, Podolsk, Russia, in October 31, 2008, and was the third of four experiments of series PARAMETER-SF. PARAMETER facility of NPO “LUTCH”, Podolsk, is designed for studies of the VVER fuel assemblies behavior under conditions simulating design basis, beyond design basis and severe accidents. The test bundle was made up of 19 fuel rod simulators with a length of approximately 3.12 m (heated rod simulators) and 2.92 m (unheated rod simulator). Heating was carried out electrically using 4-mm-diameter tantalum heating elements installed in the center of the rods and surrounded by annular UO2 pellets. The rod cladding was identical to that used in VVERs: Zr1%Nb, 9.13 mm outside diameter, 0.7 mm wall thickness. After the maximum cladding temperature of about 1900K was reached in the bundle during PARAMETER-SF3 test, the top flooding was initiated. The thermal hydraulic and SFD (Severe Fuel Damage) best estimate numerical complex SOCRAT/V2 was used for the calculation of PARAMETER-SF3 experiment. The counter-current flow limitation (CCFL) model was implemented to best estimate numerical code SOCRAT/V2 developed for modeling thermal hydraulics and severe accident phenomena in a reactor. Thermal hydraulics in PARAMETER-SF3 experiment played very important role and its adequate modeling is important for the thermal analysis. The results obtained by the complex SOCRAT/V2 were compared with experimental data concerning different aspects of thermal hydraulics behavior including the CCFL phenomenon during the reflood. The temperature experimental data were found to be in a good agreement with calculated results. It is indicative of the adequacy of modeling the complicated thermo-hydraulic behavior in the PARAMETER-SF3 test.
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Ariadji, T. "Full Field EOR Implementation of A Low Cost Surfactant Continuous Injection at Arahan-Banjarsari, South Sumatra." In Digital Technical Conference. Indonesian Petroleum Association, 2020. http://dx.doi.org/10.29118/ipa20-e-375.
Full textAbstract:
The objective of this paper is to describe a series of laboratory work results in conjunction with successful implementation of the surfactant (micellar) continuous injection in the Muara Enim sand of the Arahan-Banjarsari Field, South Sumatra. A series of lab tests were conducted using field cores and fluids taken from the Arahan-Banjarsari (AR-BS) field. The tests included phase behavior, mixture viscosity measurement, spontaneous imbibition, and static isotherm adsorption tests. Several surfactant formulas had been tested to find the most consistent and most suitable to the reservoir conditions. The surfactant injection was started in March 2009 into three AR wells. The injection was divided into 4 stages with initial concentration of 0.45% and the final concentration of 0.1%. Total volume of micellar solution injected in 110 days was 52,365 bbls. An increase in oil production was observed not only in two AR wells but also in 8 wells in the neighboring BS field (500 meters distance) after 140 days since injection of micellar solution started with injection rates of 200-250 bpd. Two BS wells were reopened and produced 28% and 54% water cut (the water cut before the two wells were shut in was 19% and 76%). This micellar solution injection managed to decrease the decline rate of 70% to 26% per year, increase production rate from AR and BS fields from 90 bopd to a peak of 220 bopd in 5 months since injection started, and reserves enhancement of 183 M bbls (10% OOIP) during 3.5 years of continuous injection. The low cost, full scale chemical EOR leads to changes in the common understanding about micellar flooding and shows a high impact on oil recovery of 183 Mbls (AB-5c sand with OOIP of 1.8 MMSTB).
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Fagundes, Diego F., Khader I. Rammah, Marcio S. S. Almeida, Julio Pequeno, Jose Renato M. S. Oliveira, and Ricardo Garske Borges. "Strength Behaviour Analysis of an Offshore Brazilian Marine Clay." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83008.
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The main purpose of this paper is to describe the geotechnical behaviour of a deep water marine clay obtained from Campos basin oil field located offshore the state of Rio de Janeiro in Brazil. The soil samples were obtained at a depth of about 1500 m using a Kullenberg piston corer. Characterization tests were undertaken on the clay samples, including water content, Atterberg limits, particle size distribution and specific density. Isotropic and anisotropic undrained triaxial tests were also carried out on both normal and over-consolidated samples to assess both the conventional strength and Cam-clay parameters. Additionally, oedometer tests were performed to evaluate the compressibility of both undisturbed and reconstituted soil samples. Finally, a series of T-bar penetrometer tests were performed on the mini-drum geotechnical centrifuge at COPPE, the University of Rio de Janeiro to establish the undrained shear strength profile. The results obtained from the T-bar tests were compared with the theoretical strength curves that were established based on the Cam-clay parameters derived from the laboratory tests. The results obtained in this study indicated a useful methodology to assess and capture the behaviour of marine clay. The assessment of strength behaviour of marine clay is quite essential in modelling of wide range of soil-offshore structure interaction problems such as pipelines, mudmats and anchors.
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Arason, Magnús, Olafur S. Haraldsson, and Steve Christer. "A curved footbridge with hidden extras." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.1995.
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<p>For improved safety and ease of travel for pedestrians and cyclists across the busy 4-lane main road Breidholtsbraut in the suburb of Breidholt in Reykjavik, Iceland, the Icelandic Road and Coastal Administration and Reykjavik City Council engaged EFLA Consulting Engineers and Studio Granda Architects for the design of a footbridge over the road. The bridge is an 86-m long, post-tensioned concrete girder in four spans and follows a curved alignment that plays on the landscaped surroundings. The attractive shape of the underside of the concrete girder is formed by a series of arcs; the cross-section having been used before by the design team to good effect. Aiming for minimized inspection and maintenance costs, the end abutments of the bridge are supported through a concealed concrete hinge, eliminating the need for bearings and construction joints. The stainless-steel wire mesh handrail was embedded into the concrete deck post casting, using a carefully planned core drilling procedure. The bridge does not have a support in the road central reserve, and this has allowed the bridge construction to proceed with only a few, short closures of the busy underlying road. The result is a well-received addition to the collection of Reykjavik footbridges.</p>