Letteratura scientifica selezionata sul tema "Limitation du fer"
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Articoli di riviste sul tema "Limitation du fer":
1
Masum Refat, Chowdhury Mohammad, e Norsinnira Zainul Azlan. "Stretch Sensor-Based Facial Expression Recognition and Classification Using Machine Learning". International Journal of Computational Intelligence and Applications 20, n. 02 (6 aprile 2021): 2150010. http://dx.doi.org/10.1142/s1469026821500103.
Abstract (sommario):
Sensor-based Facial expression recognition (FER) is an attractive research topic. Nowadays, FER is used for different application such as smart environments and healthcare solutions. The machine can learn human emotion by using FER technology. It is the primary and essential for quantitative analysis of human sentiments. FER is an image recognition problem within the broader field of computer vision. Face detection and tracking, reliable face recognition still present a considerable challenge for researchers in computer vision and pattern recognition. First, data processing and analytics are intensive and require a large number of computation resources and memory. Second, the fundamental technical limitation is its robustness in changes in the environment. Finally, illumination variation further complicates the design of robust algorithms because of changes in shadow casts. However, sensor-based FER overcomes all these limitations. Sensor technologies, especially low-power, wireless communication, high-capacity, and data processing have made substantial progress, making it possible for sensors to evolve from low-level data collection and transmission to high-level inference. This study aims to develop a stretchable sensor-based FER system. We use random forest machine learning algorithms used for training the FER model. Commercial stretchable facial expression dataset is simulated into the anaconda software. In this research, our stretch sensor FER dataset obtained around 95% accuracy for four different emotions (Neutral, Happy, Sad, and Disgust).
2
Lek, Jeniffer Xin-Ying, e Jason Teo. "Academic Emotion Classification Using FER: A Systematic Review". Human Behavior and Emerging Technologies 2023 (3 maggio 2023): 1–27. http://dx.doi.org/10.1155/2023/9790005.
Abstract (sommario):
Facial emotion expressions are among the most potent, natural, and powerful means of human communication. Due to the COVID-19 pandemic, educational institutions worldwide are forced to switch rapidly to remote and online learning. Students are currently in an emergency state and must adapt to various and readily accessible learning methods, such as mobile learning applications or an e-learning system. A systematic literature review (SLR) is conducted to extract and synthesize information such as the emotion classifier used in the facial expression recognition (FER) system, the dataset used, the preprocessing technique applied, the feature extraction approach used, and the strength and limitation of the previous studies. Based on the search criteria, 701 publications were initially retrieved from five different digital databases, of which 48 studies have been chosen as primary studies for further analysis. Based on the findings of this study, the deep learning approach is the most frequently adopted approach in classifying student emotions during online learning. FER-2013 is the most commonly used FER dataset in FER studies, while DAiSEE is the most used academic emotion dataset. Moreover, support vector machine (SVM) is the conventional learning emotion classifier that is widely used in the FER systems, while convolutional neural network (CNN) is the most frequently used deep learning classifier. Next, it was found that the number of real-time FER systems is less than that of non-real-time FER systems. Finally, the top-1 accuracy of 94.6% was achieved by the long-term recurrent convolutional network on the academic emotion dataset, and the limitation is that it has low illumination and a lack of frontal pose.
3
Managi, Shunsuke, Jingyu Wang e Lulu Zhang. "Research progress on monitoring and assessment of forestry area for improving forest management in China". Forestry Economics Review 1, n. 1 (15 aprile 2019): 57–70. http://dx.doi.org/10.1108/fer-04-2019-0012.
Abstract (sommario):
Purpose The purpose of this paper is to provide the extensive review on dynamic monitoring of forestry area in China. Design/methodology/approach Countermeasure and suggestions were proposed for three aspects including the establishment of data sets with unified standards, top-level design of monitoring and assessment and analysis models, and establishment of the decision support platform with multiple scenario simulation. Findings Finally, the authors proposed key research area in this field, i.e., improving the systematic and optimal forest management through integrating and improving the data, models and simulation platforms and coupling the data integration system, assessment system and decision support system. Originality/value The authors explored the limitation of dynamic monitoring and state of the art research on data accumulation, professional model development and the analytical platform.
4
Shin, Soo Min, Song Soo Lim e Yongsung Cho. "Estimating economic benefits of urban conifers in terms of abatement of ultrafine dust (PM2.5)". Forestry Economics Review 2, n. 1 (20 aprile 2020): 81–96. http://dx.doi.org/10.1108/fer-01-2020-0001.
Abstract (sommario):
PurposeThis study aimed to estimate the economic benefits of PM2.5 emission abatement by Red Pine, Pinus Koraiensis and Quercus, using a metering model analyzing the amount of PM2.5 absorption in Korea.Design/methodology/approachTo estimate the economic effects of PM2.5 adsorptions by trees, the frequency of hospital visits resulting from respiratory and circulatory diseases was estimated using a Probit model based on the data from National Health and Nutrition Survey.FindingsThe results show that Quercus and Pinus Koraiensis absorb and eliminate the largest amount of PM2.5. Reducing 1 ton of PM2.5 emission through the planting of trees leads to lower incidences of respiratory and circulatory diseases equivalent to the amount of 95 million won. When the trees planted are 2-year-old Red Pine, Pinus Koraiensis and Quercus, the resulting economic benefits of the PM2.5 abatement would amount to 481 million won, 173 million won and 1,027 million won, respectively. If the trees are 80 years old, the economic benefits are estimated to be 73 billion won for Red Pine, 103 billion won for Pinus Koraiensis and 38 billion won for Quercus.Research limitations/implicationsOne limitation of this study is that the weight of PM2.5 adsorbed by each leaf area entirely depended on the experimental results from a prior study and the values are likely to be different from those actually absorbed in natural surroundings. In addition, because of the lack of data from a domestic survey on the surface of leaf area or the reload flow rate of PM2.5, this study referred to data from foreign research. Unfortunately, this specific data may not reflect climatic and terrain characteristics specific to the target country. We used the annual wind speed to calculate the reload flow rate and elimination volume; however, the figures could be more accurate with hourly or daily climate variations. When estimating the health benefits of changes in PM2.5 emissions on respiratory and circulatory diseases, more segmented access to patients' hospital visits and hospital admissions are desirable. Finally, the study focused on the three major tree species of Korea, however, a more detailed study of PM2.5 reduction by various tree types is needed in the future.Originality/valueThis paper quantitatively assessed the amount of PM2.5 adsorption by each of the three tree species. Then, the economic benefits were calculated in terms of how much money would be saved on hospital visits thanks to the reduced PM2.5 levels and lower incidences of respiratory and circulatory system diseases. The net contribution of this study was to prove the trees' function of reducing PM2.5 as it relates to human health. We focused on the most common trees in Korea and compared them to provide new information on the species.
5
Robert, Mylène, Assma El Kaddouri, Jean-Christophe Perrin, Kévin Mozet, Jérôme Dillet, Jean-Yves Morel e Olivier Lottin. "The Impact of Chemical-Mechanical Ex Situ Aging on PFSA Membranes for Fuel Cells". Membranes 11, n. 5 (18 maggio 2021): 366. http://dx.doi.org/10.3390/membranes11050366.
Abstract (sommario):
A proton-exchange membrane fuel cell (PEMFC) constitutes today one of the preferred technologies to promote hydrogen-based alternative energies. However, the large-scale deployment of PEMFCs is still hampered by insufficient durability and reliability. In particular, the degradation of the polyelectrolyte membrane, caused by harsh mechanical and chemical stresses experienced during fuel cell operation, has been identified as one of the main factors restricting the PEMFC lifetime. An innovative chemical-mechanical ex situ aging device was developed to simultaneously expose the membrane to mechanical fatigue and an oxidizing environment (i.e., free radicals) in order to reproduce conditions close to those encountered in fuel cell systems. A cyclic compressive stress of 5 or 10 MPa was applied during several hours while a degrading solution (H2O2 or a Fenton solution) was circulated in contact with the membrane. The results demonstrated that both composite Nafion™ XL and non-reinforced Nafion™ NR211 membranes are significantly degraded by the conjoint mechanical and chemical stress exposure. The fluoride emission rate (FER) was generally slightly lower with XL than with NR211, which could be attributed to the degradation mitigation strategies developed for composite XL, except when the pressure level or the aging duration were increased, suggesting a limitation of the improved durability of XL.
6
Morilla, Carla Matheus, Carla Andrea Cardoso Tanuri Caldas, Amanda Cristina Alcantara Verceze Scarpellini e Patricia Leila dos Santos. "Family resources and promotion of development of children with cerebral palsy". Journal of Human Growth and Development 27, n. 2 (6 settembre 2017): 166. http://dx.doi.org/10.7322/jhgd.122707.
Abstract (sommario):
Introduction: Cerebral palsy (CP) describes a group of permanent disorders of movement and posture, causing activity limitation, attributed to a non-progressive disorder that occurs in the developing brain. The family of a child with CP becomes essential and will be much in demand, both to drive the child’s development in a favourable environment and to maintain his health. A well-functioning family and a variety of environmental stimuli can be decisive in supporting children with CP.Objective: To analyse family dynamics and the availability of child development-promoting resources in the family environment of children with CP.Methods: We recruited a sample of 25 mothers of children with PC in the Hospital das Clínicas of Ribeirão Preto. Mothers completed the Family Adaptability and Cohesion Evaluation Scale (FACES IV), the Inventory of the Family Environment Resources (FER) and a sociodemographic questionnaire. Results: The average age of mothers was 32.3 (±7.6) years; 68 per cent had completed at least primary education and 80 per cent were living with a partner. The average age of the children was 48.0 (±15.5) months; 56 per cent were girls and 68 per cent attended day care or preschool. Moderate correlations were observed between environmental resources and family functioning (0.39<r<0.70), and the FACES IV indicative scales of good family functioning showed positive correlations with the overall score of FER.Conclusion: Children with PC have few opportunities to participate in activities outside the home, but have received a good supply of resources in their homes. Well-functioning family dynamics showed an association with a greater supply of resources in the domestic environment.
7
JAHANPOUR, H., A. SEIDAVI e A. A. QOTBI. "Effects of intensity and duration of quantitative restriction of feed on broiler performance". Journal of the Hellenic Veterinary Medical Society 65, n. 2 (21 dicembre 2017): 83. http://dx.doi.org/10.12681/jhvms.15519.
Abstract (sommario):
This study was carried out to evaluate the effects of physical feed restriction method with different intensity and duration on broiler performance. One hundred and fifty Ross-breed 308 male broiler chicks in a completely randomized design were divided into five experimental treatments. The treatments included physical limitations by 25% or 50% of recommended amount on feed of broilers in two periods of 7 or 14 days. One control group was used fed ad libitum. Each limitation’s severity level was applied in τηρεε replications of 10 birds. All experimental treatments before and after the limitation period until slaughter (day 42) were fed ad libitum. The results showed that in total period broilers under the physical limitation of feed had significantly lower feed intake than controls (P < 0.05). In this research, methods and levels of physical restriction intensity and duration of feed had no significant effect on body weight for the whole experimental period. Methods and levels of food restriction severity and duration had significant effect on feed efficiency (P < 0.05).
8
Hastings, G. "The limitations of fear messages". Tobacco Control 11, n. 1 (1 marzo 2002): 73–75. http://dx.doi.org/10.1136/tc.11.1.73.
9
Dancsik, Bálint, e Nedim Márton El-Meouch. "Who Can Refinance? The Possibilities and Limitations of Market-based Refinancing in the Case of Mortgages with a Variable Interest Rate". Financial and Economic Review 18, n. 2 (giugno 2019): 5–30. http://dx.doi.org/10.33893/fer.18.2.530.
10
Holben, Diane M., Perry A. Zirkel e Grace I. L. Caskie. "Teacher Fear of Litigation for Disciplinary Actions". Journal of School Leadership 19, n. 5 (settembre 2009): 559–85. http://dx.doi.org/10.1177/105268460901900503.
Abstract (sommario):
The present study determined the extent to which teachers’ fear of litigation limits their disciplinary actions, including any significant differences by period, demographic factors, and item type. Teachers’ perceptions of limitations placed on their disciplinary actions do not substantiate the “paralyzing fear” of litigation that inhibits student discipline, as tort reform organizations claim. Teachers perceive greater limitation for nonintervention in a student fight than for intervention, with significant differences for self and others performing the action. Demographic differences support interpreting findings within context to prevent overgeneralization. Future research should examine other job-embedded scenarios to determine appropriate discipline policies and effective professional development strategies.
Tesi sul tema "Limitation du fer":
1
Jacq, Violaine. "Influence de la biodisponibilité des nutriments sur la fixation de N2 et réponse de Crocosphaera watsonii face à la limitation en fer". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066365/document.
Abstract (sommario):
La fixation de N2, ou diazotrophie, est un processus biogéochimique majeur en raison de son apport en azote nouveau dans la couche de surface de l’océan. Cependant ses facteurs de contrôle restent mal connus. Le fer, dont les concentrations de surface sont faibles, est un élément potentiellement limitant de la fixation de N2 du fait du contenu en fer important de la nitrogénase. En raison de leur découverte récente, peu d’études ont été menées sur les cyanobactéries diazotrophes unicellulaires (UCYN) pouvant être responsables de ~50% de la fixation de N2 à l’échelle globale. Des expériences en culture ont permis de caractériser et quantifier pour la première fois la réponse d’une UCYN, Crocosphaera watsonii, face à la limitation en fer. En condition de limitation en fer, il a été observé une réduction de la croissance et des taux de fixation de N2 ainsi qu’une stratégie d’adaptation des cellules avec une diminution de leur volume. La stimulation de la croissance et de l’activité de C. watsonii cultivées en condition de limitation en fer suite à l’ajout d’une pluie saharienne artificielle a permis de mettre en évidence qu’une partie au moins du fer issu de poussières désertiques est biodisponible. En Atlantique subtropical Nord, où nous avons déterminé une forte contribution de la fixation de N2 à la production nouvelle, nous avons observé une limitation de la fixation de N2 et de la production primaire principalement par les phosphates et mis en évidence le rôle des métaux traces dans le contrôle de la fixation de N2. Un ajout de pluie saharienne a permis de stimuler systématiquement la fixation de N2 et la production primaireDespite the biogeochemical importance of N2 fixation, which represents the largest source of newly-Fixed nitrogen to the open ocean, some uncertainties remain about its controlling factors. Iron (Fe) is widely suspected as a key controlling factor due to the high Fe content of the nitrogenase complex and to its low concentration in oceanic surface seawaters. N2 fixation rates associated with unicellular N2 fixing cyanobacteria (UCYN) were estimated to be ~50% of the total N2 fixation at global scale, but as they have been recently discovered few studies have been conducted on these organisms. We performed culture experiments in order to quantify for the first time the response of an UCYN, Crocosphaera watsonii, to Fe limitation. Reduction of ambient Fe concentration led to significant decreases in growth rate and N2 fixation rates per cell and we observed an adaptive strategy to Fe limitation with a cell volume reduction. Then, the enhancement of growth and activity of C. watsonii under Fe limitation condition after artificial Saharan rain addition highlighted that at least a part of the Fe released by the dust is bioavailable. In subtropical North Atlantic, an important contribution of N2 fixation to new production was observed and we showed that primary production and N2 fixation were globally P-Limited. We revealed that trace metals play a key role in controlling N2 fixation in this area. Saharan rain addition stimulated N2 fixation, presumably by supplying these nutrients. All these results contribute to our knowledge of the control of oceanic N2 fixation and provide new insight about interactions between Fe, nitrogen and carbon biogeochemical cycles
2
Koedooder, Coco. "The interplay between Fe-limitation, carbon and light in a (photo)heterotrophic bacterium". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS170.
Abstract (sommario):
Le fer (Fe) est un élément essentiel de la croissance microbienne marine, mais est présent sous forme de trace dans les eaux de surface des océans. Chez les bactéries hétérotrophes, la limitation en Fe affecte particulièrement la production d'ATP et il a été démontré que les bactéries appliquent diverses stratégies pour faire face à la présence de limitation en Fe. Les outils génétiques nous ont permis de tester deux stratégies potentielles au sein de l'organisme modèle Photobacterium angustum S14. Le shunt glyoxylique, une voie métabolique trouvée dans les bactéries aérobies contournant plusieurs étapes de TCA, s’est révélée être régulée à la hausse sous une limitation en Fe et nous proposons que la dérivation du shunt glyoxylique réoriente le métabolisme cellulaire de la chaîne de transport d’électrons, augmentant de ce fait l'efficacité métabolique de la cellule soumise à la limitation en Fe. La protéorhodopsine, une pompe à protons activée par la lumière trouvée dans plusieurs bactéries hétérotrophes, peut atténuer le stress lié au Fe si le gradient de proton produit est couplé à l'ATP synthase. Nos résultats ont montré que la protéorhodopsine augmentait à mesure que les cellules approchaient de la phase stationnaire dans des conditions à la fois remplies de Fe et limitant en Fe, mais étaient absentes pendant la phase exponentielle. Les travaux futurs visant à élucider le rôle de la protéorhodopsine, et en particulier en ce qui concerne la limitation du Fe, devraient donc être axés sur la phase stationnaire d'une cellule bactérienne. Les résultats de ce manuscrit de thèse ont contribué à la littérature actuelle sur la polyvalence des bactéries marines hétérotrophes pour faire face à la limitation en Fe et le rôle de la protéorhodopsine et du shunt glyoxylique dans l'environnement marinIron (Fe) is an essential element for marine microbial growth but is present in trace amounts in the surface waters of the ocean. In heterotrophic bacteria, Fe-limitation particularly impacts ATP production and have been shown to implement various strategies to cope in the presence of Fe-limitation. Genetic tools enabled us to test two potential strategies within the model organism Photobacterium angustum S14. The glyoxylate shunt, a metabolic pathway found in aerobic bacteria bypassing several steps within the classic tricarboxylic acid (TCA) was shown to be upregulated under Fe-limitation and we propose that the glyoxylate shunt was able to redirect a cell’s metabolism away from Fe-limiting steps within the electron transport, thereby increasing the metabolic efficiency of the cell under Fe-limitation. Proteorhodopsin, a light activated proton pump found in several heterotrophic bacteria, could alleviate Fe-stress if the produced proton gradient is coupled to ATP synthase. Our results showed that proteorhodopsin is upregulated as cells approached the stationary phase under both Fe-replete and Fe-limiting conditions but was absent during the exponential phase. Future work in elucidating the role of proteorhodopsin, and particularly under Fe-limitation, should therefore focus on the stationary phase of a bacterial cell. The results from this thesis manuscript contributed to a culminating body of work surrounding the versatility of marine heterotrophic bacteria in coping with Fe-limitation and is an appropriate addition to the literature surrounding the role of proteorhodopsin and the glyoxylate shunt within the marine environment
3
Jacq, Violaine. "Influence de la biodisponibilité des nutriments sur la fixation de N2 et réponse de Crocosphaera watsonii face à la limitation en fer". Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066365.
Abstract (sommario):
La fixation de N2, ou diazotrophie, est un processus biogéochimique majeur en raison de son apport en azote nouveau dans la couche de surface de l’océan. Cependant ses facteurs de contrôle restent mal connus. Le fer, dont les concentrations de surface sont faibles, est un élément potentiellement limitant de la fixation de N2 du fait du contenu en fer important de la nitrogénase. En raison de leur découverte récente, peu d’études ont été menées sur les cyanobactéries diazotrophes unicellulaires (UCYN) pouvant être responsables de ~50% de la fixation de N2 à l’échelle globale. Des expériences en culture ont permis de caractériser et quantifier pour la première fois la réponse d’une UCYN, Crocosphaera watsonii, face à la limitation en fer. En condition de limitation en fer, il a été observé une réduction de la croissance et des taux de fixation de N2 ainsi qu’une stratégie d’adaptation des cellules avec une diminution de leur volume. La stimulation de la croissance et de l’activité de C. watsonii cultivées en condition de limitation en fer suite à l’ajout d’une pluie saharienne artificielle a permis de mettre en évidence qu’une partie au moins du fer issu de poussières désertiques est biodisponible. En Atlantique subtropical Nord, où nous avons déterminé une forte contribution de la fixation de N2 à la production nouvelle, nous avons observé une limitation de la fixation de N2 et de la production primaire principalement par les phosphates et mis en évidence le rôle des métaux traces dans le contrôle de la fixation de N2. Un ajout de pluie saharienne a permis de stimuler systématiquement la fixation de N2 et la production primaireDespite the biogeochemical importance of N2 fixation, which represents the largest source of newly-Fixed nitrogen to the open ocean, some uncertainties remain about its controlling factors. Iron (Fe) is widely suspected as a key controlling factor due to the high Fe content of the nitrogenase complex and to its low concentration in oceanic surface seawaters. N2 fixation rates associated with unicellular N2 fixing cyanobacteria (UCYN) were estimated to be ~50% of the total N2 fixation at global scale, but as they have been recently discovered few studies have been conducted on these organisms. We performed culture experiments in order to quantify for the first time the response of an UCYN, Crocosphaera watsonii, to Fe limitation. Reduction of ambient Fe concentration led to significant decreases in growth rate and N2 fixation rates per cell and we observed an adaptive strategy to Fe limitation with a cell volume reduction. Then, the enhancement of growth and activity of C. watsonii under Fe limitation condition after artificial Saharan rain addition highlighted that at least a part of the Fe released by the dust is bioavailable. In subtropical North Atlantic, an important contribution of N2 fixation to new production was observed and we showed that primary production and N2 fixation were globally P-Limited. We revealed that trace metals play a key role in controlling N2 fixation in this area. Saharan rain addition stimulated N2 fixation, presumably by supplying these nutrients. All these results contribute to our knowledge of the control of oceanic N2 fixation and provide new insight about interactions between Fe, nitrogen and carbon biogeochemical cycles
4
Beghoura, Houda. "Modélisation de l'impact du Fer particulaire d'origine sédimentaire sur les cycles biogéochimiques marins Air‐sea turbulent fluxes from a wave‐following platform during six experiments at sea, in JGR Oceans 124 (6), June 2019 Impact of inorganic particles of sedimentary origin on global dissolved iron and phytoplankton distribution, in JGR Oceans 124 (12), December 2019". Thesis, Brest, 2020. http://www.theses.fr/2020BRES0001.
Abstract (sommario):
Il existe encore des incertitudes importantes concernant le cycle biogéochimique du fer, sa nature et la quantification de ses sources. Ce fer dissous (dFe) est considéré comme étant la forme la plus biodisponible ce qui a induit la sous-évaluation du rôle du fer particulaire (pFe) comme une source potentielle de dFe. Pourtant, la remise en suspension des sédiments libère davantage de pFe que de dFe. Dans ce contexte, ma thèse remet en question la vision traditionnelle du rôle du fer particulaire inorganique sédimentaire (pFeinorg) et propose la première modélisation de ce dernier comme source externe de dFe. Le modèle numérique PISCES a donc été adapté pour tenir compte d’un flux supplémentaire de fer en s’appuyant sur une climatologie de la dynamique à partir de la configuration NEMOPISCES globale à 2 degrés de résolution. Les simulations mettent en exergue la sensibilité de la biomasse phytoplanctonique à la forme de fer provenant des sédiments ; les limitations en macronutriments et celles en fer sont considérablement modifiées, ainsi que les gradients côte–large de chlorophylle. Le transport plus efficace du fer en tant que pFeinorg permet d’atteindre des régions éloignées de sa source. Son accumulation et sa dissolution dans les zones de convergences induisent via downwelling l’enrichissement de la surbsurface ; à ceci s’ajoute le processus de chute de la particule. Cependant, ces processus demeurent peu étudiés. Les tests de sensibilité ont montré que le gain (absence de chute) ou la perte (chute rapide) en fer dans l’océan, ou encore la prépondérance du pFe sur le dFe seraient modulés par le taux de dissolution. En revanche, la distribution de la chlorophylle est mieux représentée dans la mesure où les processus qui régissent la distribution du PFeinorg et du dFe qui en dérive sont, de concert, pris en compte. Une manière de mieux représenter les répercussions du fer sur les cycles biogéochimiques marins, serait de mieux contraindre les processus liés au PFeinorgThere are still substantial uncertainties in the iron biogeochemical cycle, including those related to the nature and magnitude of its external sources.Dissolved iron (dFe) is considered to be the most bioavailable form, which led to the underestimation of the role of particulate iron (pFe) as a potential source of dFe. Yet sediment resuspension releases more pFe than dFe. In this context, my thesis challenge the traditional view of the role of sedimentary inorganic particulate iron (pFeinorg) and proposes the first modeling of pFeinorg as a new external source of dFe. For this purpose, the PISCES numerical model has been adapted to take into account an additional iron flux based on a climatology of dynamics from the global NEMO-PISCES configuration at 2 degrees of resolution. Simulations highlight the sensitivity of phytoplankton biomass to the sedimentderived form of iron ; macronutrient limitations and iron limitations are considerably modified, as are coastal – open ocean chlorophyll gradients.The iron is more efficiently transported as a pFeinorg, allowing it to reach regions far from its source. Its accumulation and dissolution in the zones convergence zones would allow via downwelling to enrich the subsurface; in addition to this, the process of particle sinking. However, few studies have been conducted on these processes. Sensitivity tests have shown that the gain (no sinking velocity) or loss (relatively fast sinking velocity) of iron in the ocean or the preponderance of particulate iron over dissolved iron would be modulated by the dissolution rate. However the distribution of chlorophyll is better represented to the extent that the processes governing the distribution of pFeinorg and the dFe derived from it are jointly taken into account. One way to better represent the impact of iron on marine biogeochemical cycles would be to better constrain the processes associated with pFeinorg
5
Tonnard, Manon. "Biogeochemical cycle of Iron : distribution and speciation in the North Atlantic Ocean (GA01) and the Southern Ocean (GIpr05) (GEOTRACES)". Thesis, Brest, 2018. http://www.theses.fr/2018BRES0115/document.
Abstract (sommario):
Il est désormais établi que la disponibilité en fer (Fe) contrôle environ 50% de la production primaire des océans du monde. Cependant, les processus régissant l’intensité des puits et des sources du Fe ainsi que la prédominance relative de ces sources au sein des divers bassins océaniques, sont elles-mêmes peu contraintes. Par ailleurs, une fois entrées dans le système océanique, la disponibilité et l’accessibilité des diverses formes de Fe pour les organismes marins restent incertaines. La réactivité du Fe au sein de l’environnement marin dépend de son état d’oxydoréduction et de complexation. Le fer dissous (DFe) est souvent considéré comme la fraction la plus biodisponible pour le phytoplancton et les ligands organiques du Fe augmentent vraisemblablement le temps de résidence du Fe et permettent des concentrations de DFe bien plus élevées que sa solubilité inorganique ne le permet dans l’eau de mer (10 pmol L-1).Dans ce contexte et s’inscrivant dans le programme international GEOTRACES, cette thèse a pour but principal d’implémenter notre savoir du cycle biogéochimique du Fe dans l’océan et ses interactions avec la structure des communautés phytoplanctoniques, en particulier afin de mieux contraindre les formes biodisponibles du Fe. Ainsi, les objectifs de cette thèse reposent sur trois questions scientifiques : 1) Quelles sont les distributions, sources, et puits de Fe ? 2) Quel est le lien entre la structure des communautés phytoplanctoniques et les concentrations en DFe ? 3) Comment la spéciation organique du DFe impacte ses concentrations et sa biodisponibilité ? Ces trois questions ont été explorées sur de deux zones d’études contrastées : l’océan Nord Atlantique (GEOVIDE, GA01 GEOTRACES voyage, PIs G. Sarthou and P. Lherminier) étant occasionnellement et saisonnièrement appauvri en Fe et l’océan Austral (HEOBI, GIpr05 GEOTRACES voyage, PIs A. Bowie, T. Trull, Z. Chase) l’étant de manière permanenteIt is now recognized that iron (Fe) availability dictates the efficiency of the global biological carbon pump such that any perturbation of Fe sources will lead to changes in the carbon cycles with consequences on both other major nutrient cycles and the climate system, controlling about 50% of the worldwide ocean primary production. However, the underlying processes themselves that affect the pathways releasing and trapping Fe, and the relative predominance of Fe sources among the different ocean basins are still poorly constrained. More importantly, the extent to which both the chemical and the physical speciation of Fe are available and accessible for marine organisms, once it enters the ocean, remains uncertain. The reactivity of Fe within the marine environment will depend on its redox and complexation state, with DFe generally considered the most bioavailable form for phytoplankton and Fe-binding organic ligands likely increasing the residence time of Fe that enables enhanced DFe concentrations way above its inorganic solubility in seawater (c.a. 10 pmol L-1).In this context and as part of the international GEOTRACES program, this thesis aims at improving our knowledge on Fe biogeochemical cycle in the ocean and its interactions with the phytoplankton community structure to better constrain the bioavailable forms of Fe. The objectives of this thesis revolve around three scientific questions: 1) What are the distributions, sources, and sinks of dissolved iron? 2) What is the link between the phytoplankton community structure and dissolved iron concentrations? 3) How the organic speciation of dissolved iron affects its concentrations and bioavailability for the phytoplankton community? These three questions were investigated through two contrasted areas: the North Atlantic Ocean (GEOVIDE, GA01 GEOTRACES voyage, PIs G. Sarthou and P. Lherminier) and the Southern Ocean (HEOBI, GIpr05 GEOTRACES voyage, PIs A. Bowie, T. Trull, Z. Chase) the former being occasionally seasonally depleted in Fe, the latter permanently
6
Godrant, Aurélie. "The role of superoxide in iron acquisition by marine phytoplankton". Brest, 2009. http://www.theses.fr/2009BRES2061.
Abstract (sommario):
Le rôle clef du fer dans le cycle biogéochimique du carbone et de l’azote dans l’océan a été mis en évidence au cours de la dernière décennie. Une des découvertes majeures récentes en océanographie biologique est la limitation de la croissance du phytoplancton par la disponibilité en fer dans au moins 40% de l’océan mondial. Or, la chimie de cet élément dans l’océan est particulièrement complexe et la forme sous laquelle il est disponible pour le phytoplancton reste encore mal connue. Plusieurs mécanismes sont utilisés par le phytoplancton marin pour améliorer la solubilité du fer en eau de mer et parvenir à absorber les quantités suffisantes en fer nécessaires à leur survie. Un de ces mécanismes implique la production de radicaux superoxyde en milieu extracellulaire, ce qui accroît la bio-disponibilité du fer en eau de mer en réduisant la forme Fe(III) sous forme Fe(II), plus bio-disponible aux cellules de phytoplancton. Les objectifs principaux de ce travail étaient de i) développer une méthode appropriée pour détecter la production de superoxyde en milieu extracellular par n’importe quelle cellule de phytoplancton marin, et ii) examiner la relation entre la production extracellulaire de superoxyde et l’absorption du fer par la cyanobactérie Trichodesmium erythraeum IMS101. Une méthode de détection du superoxyde a été développée, qui utilise du red-CLA ou du MCLA, deux sondes chimiluminescentes spécifiques à la détection du superoxyde, qui ont donné des résultats fiables, même sur de très faibles quantités d’échantillons. En effet, comparée aux autres méthodes employées, la détection de la production du superoxyde par microplaques permet de réduire le volume d’échantillon par 10, et de réduire le temps d’analyse de tréplicats d’un échantillon, d’un blanc et de trois standards à 10 minutes. De plus, cette méthode présente une large gamme de travail avec une limite de détection de 0,076 pmol/s, ce qui lui confère un grand avantage pour le travail sur le phytoplancton marin. Les taux de production de superoxyde en milieu extracellulaire par la cyanobatérie Trichodesmium erythraeum ont été mesurés en condition de laboratoire et allaient de 0,93 à 16,21 pmol/trichome/h. La limitation en fer des cellules de Trichodesmium résultat en une augmentation de ce taux de production, qui a été multiplié par un facteur 2,9 entre les cellules non limitées et les cellules limitées en fer. Il a aussi été montré que la production de superoxyde suivait un rythme diurne avec une forte augmentation du taux de production en milieu du cycle « jour», spécialement marqué pour les cultures maintenues en milieu pauvre en fer. Les taux de production extracellulaire de superoxyde et d’absorption du fer par Trichodesmium ont été mesurés simultanément sur des cultures pré-limitées ou non limitées en fer. Les taux d’absorption étaient 10 fois plus élevés pour les cultures non limitées, sauf lorsqu’un composé réducteur (acide ascorbique) était ajouté. Dans ce cas, les taux d’absorption des deux cultures étaient similaires. De plus, les deux cultures ont montré une plus grande aptitude à absorber le fer lié à des ligands faibles comme le citrate. Dans l’ensemble, les résultats ont montré une relation entre la production de superoxyde et l’absorption de fer par Trichodesmium, mais aucune influence directe entre ces deux processus n’a pu être démontrée. La méthode de détection du superoxyde par microplaque a été utilisée lors de campagnes sur la Grande Barrière de corail en Australie. L’analyse de deux blooms de Trichodesmium a montré de forts taux de production de superoxyde, en cohérence avec les analyses effectuées au laboratoire. De plus, l’utilisation de cette méthode (entre autres) a permis de démontrer une accumulation d’espèces Fe(II) en concentrations biologiquement significatives, quand la concentration en superoxyde dans l’eau de mer était inférieure à 1 nM. Par contre, lorsque cette concentration se trouvait supérieure à 1nM, la plupart des espèces réduites (Fe(II)) étaient réoxidées, ce qui résultait en un fort taux de production de peroxyde d’hydrogène du à la dismutation du superoxyde. Dans l’ensemble, cette étude a permis le développement d’une méthode de détection de la production de superoxyde par le phytoplancton marin en milieu extracellulaire qui peut être utilisée au laboratoire ou en conditions d’étude sur le terrain. Nous avons aussi démontré que les cellules de Trichodesmium erythraeum IMS101 produisent de grandes quantités de superoxyde, en particulier lorsqu’elles sont limitées en fer. L’étude des taux d’absorption du fer par ces même cellules a démontré une forte relation entre ce processus et la production de superoxyde par les cellules: ces résultats sont en accord avec l’hypothèse que le modèle d’absorption du fer par le phytoplancton marin «Fe’» serait fortement influencé par ce type d’organisme capable de modifier l’équilibre redox du milieu présent à la surface des cellulesIt is hypothesised that, under iron limitation, phytoplankton cells develop biochemical mechanisms to increase their iron uptake efficiency with one of these mechanisms involving the production of superoxide in the extracellular environment that increases the bioavailability of iron in seawater by reducing Fe(III) to the more soluble Fe(II). The main objectives of this work were 1) to develop an appropriate method to detect extracellular production of superoxide by marine phytoplankton, and 2) to examine the relationship between extracellular production of superoxide and iron acquisition by Trichodesmium erythraeum. A method to measure superoxyde production is described using red-CLA and MCLA probes, yielding considerable improvement for analysis compared to other available methods. Extracellular superoxide production and iron uptake rates were measured simultaneously on iron replete and iron deplete Trichodesmium erythraeum IMS 101 laboratory cultures : iron starvation leads to a 2. 9-fold increase in superoxide production rate and 10-fold decrease in the iron uptake rate (except when a reducing compound was added) compared to iron replete cultures. Extracellular superoxide production shows a pronounced circadian rythm in iron deplete cultures, but less so in iron replete cultures. Overall, no direct impact of extracellular superoxide production by Trichodesmium is observed, but both processes are shown to be related. Both iron deplete and iron replete cultures demonstrate greater ability to uptake iron bound to weaker iron-binding ligands such as citrate. Application of the method to field studies in the Great Barrier Reef lagoon showed an accumulation of biologically significant concentrations of reduced trace metals including Fe(II) when the concentration of superoxide was lower than 1 nM. When the concentration of superoxide was higher than 1 nM, most of the reduced species were oxidised resulting in high rates of hudrogen peroxide production rates, consistent with laboratory studies. Overall, this thesis permitted the development of a method to detect superoxide production rates by marine phytoplankton cells that could be used routinely in field studies. The observations are in accord with the conclusion that fit the ongoing hypothesis that the extablished Fe' uptake model for phytoplankton would be strongly influenced by such organisms that are able to modify the redox equilibrium of the solution at their cells surface
7
Lindqvist, Erica, e Maria Heimdahl. "Kvinnors upplevelse och erfarenheter av att leva med urininkontinens : En situation att acceptera och anpassa sig efter". Thesis, Högskolan Väst, Avdelningen för omvårdnad - grundnivå, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-10734.
Abstract (sommario):
Urininkontinens är ett problem alla kan drabbas av. Det innebär att personen läcker urin eller kissar på sig. Det ses som ett vanligt folkhälsoproblem i hela världen och det förekommer mest hos kvinnor. Det påverkar kvinnorna och hämmar dem i det dagliga livet. Hämningen grundar sig i rädsla och oro för att läcka samt lukta urin. Kvinnorna med urininkontinens upplever att ämnet är tabubelagt samt nedtystat och associeras med skamkänslor. De känner en daglig påverkan av urininkontinensen och den planerade livsplanen spricker med en överhängande känsla av maktlöshet samt frustration. De försöker hitta olika sätt att acceptera sina symtom men flertalet av kvinnorna ser symtomen som en oundviklig del av livet. Ett problem som kommer med stigande ålder eller en åkomma efter förlossning. Kvinnor som är äldre än femtio år har lättare att acceptera sin urininkontinens än de som är trettio år. De okontrollerade symtomen ger kvinnorna en känsla av förlorad kroppskontroll och sårbarhet. Detta kan leda till dåligt självförtroende och depression. Kvinnorna begränsas i sociala sammanhang och de hindras att utföra fysiska aktiviteter till följd av nervositet att läcka samt lukta urin. Detta upplevs som en förlust i vardagen. Kvinnorna uttrycker även en försämring i deras sexuella relationer och de känner en svårighet att vara spontana i sexuella aktiviteter. Mindre feminitet och en känsla av att inte vara fräsch uttrycks också av kvinnorna. Till följd av detta känner de en sämre självkänsla. Olika strategier används för att fungera i det dagliga livet. Vilket kan innebära att de anpassar sin klädsel och förbereder sig med extra inkontinensskydd för att dölja fläckar från läckage. De tar även alltid reda på tillgång till toaletter i offentliga miljöer. Ett annat problem dessa kvinnor upplever är ett ignorant bemötande av vårdpersonal och brist på kunskap om urininkontinens. Kvinnorna önskar en mer förstående attityd och bättre kommunikation i vården för att få möjlighet till rätt behandling. Vården har mycket att förbättra i mötet med dessa kvinnor både professionellt samt kunskapsmässigt och i öppenheten till ämnet. Det går inte att förvänta sig att kvinnorna tar sina egna besvär på allvar när inte vårdpersonalen gör det.Background: Urinary incontinence denotes an involuntary leakage from the bladder which can affect women of all ages, but leakage problems are often more common with rising age. It is a common issue, however there is a large unrecorded number of women who do not seek medical attention for their urinary incontinence. Urinary incontinence is very costly for the society because of the medical and social disability it causes the affected. Aim: To illuminate the experiences of women living with urinary incontinence Method: A literary study was done where nine scientific articles were examined and analyzed according to a five step model. Results: The women experienced their urinary incontinence as taboo and shameful. The issue was too intimate and private and therefore unnatural to talk about. Their leakage lead to fear and nervousness which made them end up in a vulnerable situation. This affected them on several emotional levels both psychosocial, psychological and physical. The women experienced an ignorance and a nonchalant attitude from their care providers which caused an hesitancy in their search of healthcare. They experienced that their bodies were unreliable which lead to a reduced spontaneity and restrictions in life. Conclusion: Urinary incontinence is not solely an issue with leaking urine, it is affecting the women's lives as a whole on many levels. The hindrance that the urinary incontinence caused the women on a daily basis made them feel a sense of loss and affected their joy and zest of life. It requires an improvement of healthcare praxis in order to meet these women in a professional and trustworthy manner.
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Fornander, Camilla, e Josefine Karlsson. "Sjuksköterskans erfarenheter i mötet med barn som far illa". Thesis, Hälsohögskolan, Högskolan i Jönköping, HHJ, Avd. för omvårdnad, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-22615.
Abstract (sommario):
Sverige har en lagstadgad anmälningsplikt som är obligatorisk för alla som i sitt arbete kommer i kontakt med barn. Lagen är tydlig med att alla misstänka missförhållanden skall anmälas. Forskning visar att anmälningsplikten inte alltid fungerar och att det bara är en liten del av de barn som riskerar att fara illa som kommer till socialtjänstens kännedom. Vidare forskning visar att få anmälningar kommer från hälso- och sjukvården. Syftet var att beskriva sjuksköterskans erfarenheter i mötet med barn som far illa eller riskerar att fara illa. Litteraturstudien genomfördes med kvalitativ design och sökningar har gjorts i CINAHL, MEDLINE och PsycINFO. Åtta artiklar ansågs relevanta. Under analysen framkom tre teman: en emotionell utmaning, att känna sig begränsad och att våga agera. Resultatet visar att sjuksköterskan blir berörd i mötet med barn som far illa. Vidare beskriver sjuksköterskan osäkerhet, bristande kunskap och brister i organisationen. Sjuksköterskans professionella trygghet beskrivs utifrån kunskap och förvärvad erfarenhet. Det är angeläget att sjuksköterskans yrkeskompetens upprätthålls samt att det finns stöd att tillgå för att utveckla omvårdnaden kring barn som far illa.In Sweden, everyone who comes in contact with children through their work has a statutory obligation to report child abuse. The law clearly states that any suspected child abuse must be reported. Research shows that the reporting does not always work. Only a small proportion of the children who might be victims of abuse come to the knowledge of Social Services. Further research shows that few notifications come from individuals within the health care system. The aim of this literature review was to describe nurses’ experiences of encounters with chil-dren who are victims of abuse or who are at risk of being abused. A qualitative design was used. CINAHL, MEDLINE and PsycINFO were used to select the articles, eight of which met the selection criteria. During the analysis, three themes emerged: An Emotional Challenge, Feeling Limited, and Daring to Act. The results show that the nurses are emotionally affected by their contact with abused children. The nurses also describe feelings of insecurity, a lack of knowledge, and organizational deficiencies. The nurses’ professional security is described as stemming from knowledge and experience. It is very important that the nurses’ professional competence is maintained and that there is support available in order to develop the care of abused children.
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Ghaffari, Navid. "Effect of amino acid limitation and supplementation in Chinese hamster ovary fed-batch cultures". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52061.
Abstract (sommario):
Fed-batch processes are the industrial norm for the production of recombinant proteins such as monoclonal antibodies (MAb) from Chinese hamster ovary (CHO) cells. Optimization of such processes is an important objective of industry process development groups. Amino acid availability is a key factor that is controlled to achieve the desired product yield and quality. In order to improve fed-batch productivity, the individual effects of limiting the three depleted amino acids were investigated for three antibody expressing CHO cell lines. Specifically, the effects of limiting glutamine, asparagine and cysteine on the cell growth, metabolism, antibody productivity and quality were investigated. Cysteine limitation was found to be detrimental to both the cell proliferation and the productivity for all three CHO cell lines. In contrast, asparagine limitation had no significant effect on either their growth or productivity. Glutamine limitation resulted in a reduction in growth but not in cell specific productivity, again for all three cell lines. Neither glutamine nor asparagine limitation significantly affected the MAb glycosylation. However, the fucosylation ratio was reduced in the absence of cysteine. It was confirmed that cysteine is a rate limiting factor for the productivity and growth of the three CHO cell lines. Replenishing cysteine after 1 day of the limitation allowed the cells to regain their growth and productivity; however, this was not observed after 2 days of cysteine limitation. Under cysteine limitation there was increased oxidative damage to the mitochondria, possibly caused by reduced synthesis of co-enzyme A which is essential for functionality of the TCA cycle. Finally, a fed-batch protocol was developed to improve the MAb productivity of CHO-DXB11 cells and the results were compared to the results with a commercial feed. Although use of the commercial feed resulted in higher maximum cell and final MAb concentrations, maintaining the levels of cysteine yielded cell specific production rates that were comparable to the commercial feed culture. Overall, the results of this study showed that amino acid limitations have varied effects on the performance of CHO cell cultures, such that it is important to focus process development efforts on the critical amino acids.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Rasran, Leonid [Verfasser]. "Impact of seed- and microsite-limitation on species diversity in fen grasslands / Leonid Rasran". Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019621184/34.
Libri sul tema "Limitation du fer":
1
Reynolds, Barnabas. Shipowners limitation of liability. Alphen aan den Rijn, The Netherlands: Kluwer Law International, 2012.
2
University of Southampton. Institute of Maritime Law., a cura di. Limitation of shipowners' liability: The new law. London: Sweet & Maxwell, 1986.
3
Griggs, Patrick. Limitation of liability for maritime claims. 3a ed. London: LLP, 1998.
4
Griggs, Patrick. Limitation of liability for maritime claims. London: Lloyd's of London Press, 1986.
5
Griggs, Patrick. Limitation of liability for maritime claims. 2a ed. London: Lloyd's of London Press, 1991.
6
United States. Congress. House. Committee on Veterans' Affairs., a cura di. Legislative history of the ten dollar attorney fee limitation in claims for veterans' benefits. Washington: U.S. G.P.O., 1987.
7
US GOVERNMENT. An Act to Authorize Extension of Time Limitation for a FERC-issued hydroelectric license. [Washington, D.C.?: U.S. G.P.O., 1996.
8
United States. Congress. House. Committee on Veterans' Affairs., a cura di. Legislative history of the ten dollar attorney fee limitation in claims for veterans' benefits. Washington: U.S. G.P.O., 1987.
9
Yeomans, Kathleen. The able gardener: Overcoming barriers of age & physical limitations. Pownal, Vt: Storey Communications, 1992.
10
United States. Congress. Senate. Committee on Energy and Natural Resources. Extension of time limitation for a FERC-issued hydroelectric license: Report (to accompany S. 611). [Washington, D.C.?: U.S. G.P.O., 1995.
Capitoli di libri sul tema "Limitation du fer":
1
Tugui, Alexandru. "The AI’s Ethical Limitations from the Societal Perspective: An AI Algorithms’ Limitation?" In Algorithms for Intelligent Systems, 27–32. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-9436-6_3.
2
Oprea, Corina. "Limitations". In The Effects of Impartiality Disclosure on Brand Objectives for No and Multiple Product Endorsements, 209–11. Wiesbaden: Springer Fachmedien Wiesbaden, 2023. http://dx.doi.org/10.1007/978-3-658-41364-4_16.
3
Uschold, Michael. "OWL Limitations". In Demystifying OWL for the Enterprise, 163–84. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-031-79482-7_7.
4
Wallwork, Adrian. "Discussing your limitations". In English for Academic Research, 109–18. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-31072-0_7.
5
Senior, Mike. "Low-End Damage Limitation". In Mixing Secrets for the Small Studio, 53–62. Second edition. | New York, NY : Routledge, 2018. | Series: Sound on Sound presents: Routledge, 2018. http://dx.doi.org/10.4324/9781315150017-4.
6
Wallwork, Adrian. "Discussing Your Limitations". In English for Writing Research Papers, 157–68. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-26094-5_9.
7
Greenberg, David J. "Know your limitations". In Screenwriting for Micro-Budget Films, 15–26. London: Routledge, 2021. http://dx.doi.org/10.4324/9781003138969-2.
8
Lange, Nick. "Limitations and Outlook". In Future Perspectives for Higher Education, 265–69. Wiesbaden: Springer Fachmedien Wiesbaden, 2023. http://dx.doi.org/10.1007/978-3-658-40712-4_12.
9
Fleming, Robert S. "Knowing One’s Limitations". In Preparing for a Successful Faculty Career, 241–44. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-50161-6_53.
10
Walker, Jeffery T., e Craig Hemmens. "Police Power and Limitations". In Legal Guide for Police, 29–34. 11th edition. | New York, NY; Milton Park, Abingdon, Oxon: Routledge, an imprint of the Taylor & Francis Group, 2019.: Routledge, 2019. http://dx.doi.org/10.4324/9780429400230-3.
Atti di convegni sul tema "Limitation du fer":
1
Zhang, Zhenyong, Yawei Zhou e Jinyuan Zhang. "Assessment on Design Factors of China’s Natural Gas Pipeline Based on Reliability-Based Design Method". In 2016 11th International Pipeline Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ipc2016-64186.
Abstract (sommario):
Although the traditional method based on stress analysis is simple and convenient, the main limitation is that it does not reflect the actual failure mechanisms (or limit states). A pipeline network database of about 40 thousand kilometers comprising 258 design cases that represent combinations of steel grade, diameter, pressure, and location class is established, in order to evaluate and improve the design factors specified in the Chinese standard “Code for design of gas transmission pipeline engineering” (GB 50251). Referring to the research report “Target Reliability Levels for the Design and Assessment of Onshore Natural Gas Pipelines” accomplished by C-FER in 2005, the critical wall thicknesses and corresponding equivalent design factors are calculated by using reliability-based method to meet specified reliability targets. The research shows that the equivalent design factors obtained by Reliability-Based Design (RBD) method tend to increase as the pipe diameters get larger. The new design factors are smaller than those specified in the design code for pipelines with small diameter in location class 1 and 2, and larger than those in the design code for the other pipelines. Therefore, design factors are modified in each location class. The new factors are specific to pipes with small diameter (D ≤ 508mm), medium diameter (508mm < D < 711mm), and large diameter (711mm ≤ D ≤ 1219mm), thus enhancing the rationality and practicability of design factors.
2
Wu, Bae-Ian. "Limitation on far-field super directivity using transformation optics". In 2013 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium). IEEE, 2013. http://dx.doi.org/10.1109/usnc-ursi.2013.6715470.
3
Shoji, Yasumasa. "Things to Concern for Finite Element Analyses". In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45718.
Abstract (sommario):
Recently FEA (Finite Element Analysis) is used in various engineering fields such as for design, verification, validation trouble-shooting and other applications. As the more users are treating FEA, the quality of analyses has become the larger issue. Finite Element Method (FEM) is just a calculation method to reproduce physical phenomena, and it has functional limitation in nature. As the software becomes more and more user-friendly, the limitation is hidden in the operation. However, as the limitation still exists in principle, users must be aware of it when using the FEA software. This paper will address about the issues that we are easily trapped in modeling, such as element selection, boundary conditions and other conditions.
4
Kuhl, J., M. Klingenstein, M. Lambsdorff, C. Moglestue, J. Rosenzweig, A. Axmann, Jo Schneider e A. Hülsmann. "Limitations of the Impulse Response of GaAs MSM-Photodetectors". In Picosecond Electronics and Optoelectronics. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/peo.1991.thc2.
Abstract (sommario):
Interdigitated Metal-Semiconductor-Metal (MSM) Schottky diodes fabricated on GaAs and other III-V compounds are sensitive high speed photodetectors for multigigabit optical data processing systems. The compatibility of the fabrication process with the process technology of planar high speed electronic devices like FET's makes them extremely attractive for ultrafast integrated optoelectronic circuits. Narrow Schottky contact spacing permitting rapid carrier extraction after photoexcitation and a small active area in order to minimize the parasistic capacitance are the key design features of these diodes. First attempts to model the intrinsic transport of photoexcited carriers in MSM-diodes by a one-dimensional Monte Carlo simulation predict temporal separation of the electron and hole current /1,2/ and durations of electron and hole pulse of a few picoseconds and several ten picoseconds, respectively. Although frequency bandwidths in excess of several ten GHz for such detectors have been reported by several groups /3,4/ a direct comparison of theoretical and experimental results and a definite identification of the performance-limiting factors is still missing, so far.
5
Li, Xiao-cong, e You-fei Tian. "Nonlinear Control of Power Limitation for Doubly-Fed Wind Power Generation System". In 2011 Asia-Pacific Power and Energy Engineering Conference (APPEEC). IEEE, 2011. http://dx.doi.org/10.1109/appeec.2011.5748770.
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HUANG, Z., G. STUPAKOV e S. REICHE. "EMITTANCE LIMITATION OF A CONDITIONED BEAM IN A STRONG FOCUSING FEL UNDULATOR". In Proceedings of the 46th Workshop of the INFN ELOISATRON Project. WORLD SCIENTIFIC, 2007. http://dx.doi.org/10.1142/9789812772176_0009.
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Ravaioli, Riccardo, Guillaume Urvoy-Keller e Chadi Barakat. "Characterizing ICMP rate limitation on routers". In 2015 IEEE International Conference on Signal Processing for Communications (ICC). IEEE, 2015. http://dx.doi.org/10.1109/icc.2015.7249285.
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Pillin, Nicolas, Catherine Dehollain e Michel J. Declercq. "Read range limitation in IF-based far-field RFID using ASK backscatter modulation". In 2009 Ph.D. Research in Microelectronics and Electronics (PRIME). IEEE, 2009. http://dx.doi.org/10.1109/rme.2009.5201297.
9
Csonka, Paul L. "Insertion Devices, Future Developments, Limitations". In International Conference on Insertion Devices for Synchrotron Sources, a cura di Ingolf E. Lindau e Roman O. Tatchyn. SPIE, 1986. http://dx.doi.org/10.1117/12.950941.
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Miller, Zachary, Massimiliano Fratoni e Vedant Mehta. "Thermomechanical Limitations of Uranium Mononitride". In Nuclear and Emerging Technologies for Space (NETS 2023). Illinois: American Nuclear Society, 2023. http://dx.doi.org/10.13182/nets23-41902.
Rapporti di organizzazioni sul tema "Limitation du fer":
1
Frey, W., e E. Tombler. TV BANDWIDTH LIMITATION FOR COMPUTER PAGE DISPLAY. Office of Scientific and Technical Information (OSTI), febbraio 1987. http://dx.doi.org/10.2172/1151183.
2
Doebert, S. Gradient Limitations for High-Frequency Accelerators. Office of Scientific and Technical Information (OSTI), settembre 2004. http://dx.doi.org/10.2172/833031.
3
Miller, Kyle, e Andrew Lohn. Onboard AI: Constraints and Limitations. Center for Security and Emerging Technology, agosto 2023. http://dx.doi.org/10.51593/2022ca008.
Abstract (sommario):
Artificial intelligence that makes news headlines, such as ChatGPT, typically runs in well-maintained data centers with an abundant supply of compute and power. However, these resources are more limited on many systems in the real world, such as drones, satellites, or ground vehicles. As a result, the AI that can run onboard these devices will often be inferior to state of the art models. That can affect their usability and the need for additional safeguards in high-risk contexts. This issue brief contextualizes these challenges and provides policymakers with recommendations on how to engage with these technologies.
4
Klote, John H., Harold E. Nelson, Scot Deal e Bernard M. Levin. Staging areas for persons with mobility limitations. Gaithersburg, MD: National Institute of Standards and Technology, 1992. http://dx.doi.org/10.6028/nist.ir.4770.
5
Johnson. L51935 Limitations of Cellulosic-Coated Electrodes. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), ottobre 2003. http://dx.doi.org/10.55274/r0010434.
Abstract (sommario):
Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for stovepipe welding of pipelines because they are well suited for deposition of one-sided welds and are capable of high deposition rates when welding downhill. Despite advances in mechanized welding technology and the development of low-hydrogen consumables suitable for pipeline girth welding, manual welding, using cellulosic-coated electrodes is still widely utilized for pipeline construction throughout the world. Several incidents involving significant hydrogen-assisted cracking in the weld metal of pipeline girth welds made using cellulosic-coated electrodes have been reported recently. Two of these cases required removal of many welds at an expense of over $4 million dollars, in spite of established procedures having been used. The objectives of this project were to identify the primary mechanisms contributing to transverse cracking of field welds and to provide recommendations regarding safe preheat/interpass temperatures that should be utilized when welding heavy-wall pipe and fittings using cellulosic-coated electrodes. Two cases of severe weld metal hydrogen-assisted cracking were investigated. In each case, the composition of the weld metal was substantially richer that would typically be expected for E8010-G electrodes. Subsequent investigation into factors influencing the composition of weld metal from cellulosic-coated electrodes revealed that arc length has a pronounced effect on carbon, manganese, and silicon recovery. The increase in composition observed with variation in arc length could not explain the extremely rich compositions observed in the cracked girth welds, however. Subsequent investigation demonstrated that it was possible to effectively double the manganese concentration and triple the silicon concentration when using cellulosic coated electrodes that have low coating moisture content.
6
Vierow, Karen. COUNTERCURRENT FLOW LIMITATION EXPERIMENTS AND MODELING FOR IMPROVED REACTOR SAFETY. Office of Scientific and Technical Information (OSTI), settembre 2008. http://dx.doi.org/10.2172/938628.
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Allemeier, R. T., J. W. Wagner e K. L. Telschow. Limitations for heterodyne detection of Brillouin scattered light. Office of Scientific and Technical Information (OSTI), gennaio 1995. http://dx.doi.org/10.2172/34422.
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Drew, Christopher T. Limitations for a Successful Army Leader Development Strategy. Fort Belvoir, VA: Defense Technical Information Center, maggio 2013. http://dx.doi.org/10.21236/ada583863.
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Syverson, Paul. Limitations on Design Principles for Public Key Protocols. Fort Belvoir, VA: Defense Technical Information Center, gennaio 1996. http://dx.doi.org/10.21236/ada465132.
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Gennett, Thomas. Position Paper: Hydrogen Spillover Limitations for Onboard Hydrogen Storage. Office of Scientific and Technical Information (OSTI), gennaio 2019. http://dx.doi.org/10.2172/1489894.