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Lentz, Rasmus. "Models of Wages and Mobility in Frictional Labor Markets with Random Search". Revue économique Vol. 51, n. 1 (27 febbraio 2024): 113–45. http://dx.doi.org/10.3917/reco.751.0113.
Testo completoAbstract (sommario):
J’étudie les modèles de détermination de l’équilibre des salaires et de la mobilité avec frictions sur le marché du travail. La recherche d’un emploi est aléatoire. La concurrence entre les entreprises se fait en termes de promesses de valeur faites aux travailleurs. La nature exacte de cette concurrence dicte la répartition des promesses de valeur dans l’économie. La mobilité des travailleurs et l’allocation des emplois sont souvent comprises directement à partir de cette partie du modèle. L’étude détaille comment les restrictions sur les contrats de travail traduisent les valeurs des contrats en salaires .
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Thibout, Charles. "Les ancrages nationaux d’une multinationale". Réseaux N° 244, n. 3 (30 settembre 2024): 187–224. http://dx.doi.org/10.3917/res.245.0187.
Testo completoAbstract (sommario):
Si le pouvoir des multinationales, et des GAFAM en particulier, apparaît comme l’un des faits politiques et économiques majeurs de notre époque, s’exerce-t-il sans frictions au contact des espaces de pouvoir nationaux qu’elles rencontrent au gré de leur internationalisation ? Cet article entend contribuer à y répondre, en analysant l’implantation de Google en France à travers le prisme de ses recrutements. Fondée sur des entretiens, l’exploitation d’archives et une analyse prosopographique, cette enquête permet de rendre compte des efforts d’adaptation produits par une multinationale du numérique pour pénétrer le marché français, alors que la firme est précocement l’objet de mobilisations hostiles et d’une mise en problème politique. L’objectif de l’article est d’analyser ce processus d’adaptation, qui passe par le recrutement de salariés et de dirigeants aux propriétés hybrides, situés à l’interface entre Google et le champ du pouvoir national. Les ancrages nationaux de ces recrues en général, et des représentants d’intérêts en particulier, aménagent des espaces de négociation où se jouent l’entrée de la firme dans le travail gouvernemental et la reconnaissance de sa légitimité à s’insérer dans certains secteurs d’action publique.
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Restrepo, María Isabel, e Diana Constanza Restrepo. "El canal del crédito bancario en Colombia: 1995-2005. Una aproximación mediante modelos de umbral." Lecturas de Economía, n. 67 (31 luglio 2009): 99–118. http://dx.doi.org/10.17533/udea.le.n67a2022.
Testo completoAbstract (sommario):
El canal del crédito bancario, que amplifica los efectos del canal tradicional de la política monetaria, hace énfasis en la estructura y las fricciones del mercado financiero como determinantes del gasto agregado. Este artículo analiza y verifica la existencia del canal del crédito bancario en Colombia estimando un modelo propuesto por Michael Gibson en 19971997, quien utiliza regresiones de umbral para determinar el impacto de la política monetaria sobre la demanda agregada. Los resultados obtenidos no permiten descartar la existencia de este mecanismo de transmisión en Colombia durante el periodo analizado, aunque éste parece operar solo a través de la política monetaria contraccionista. Palabras clave: política monetaria, mecanismos de transmisión, canal de crédito bancario, modelos de umbral. Clasificación JEL: C12, C52, E44, E52, G11. Abstract: The Bank Credit Channel, which amplifies the effects of the traditional channel of monetary policy, emphasizes on the structure and frictions of financial markets as determinants of aggregate spending. This paper aims at analyze and verify the existence of the bank credit channel in Colombia estimating a model proposed by Gibson (1997) which uses threshold regressions as a way to determine the impact of monetary policy on aggregate demand. Results do not allow dismissing the existence of this transmission mechanism in Colombia during the analyzed period, although it seems to operate only through contractionary monetary policy. Keywords: monetary policy, transmission mechanisms, bank lending channel, threshold regressions. JEL classification: C12, C52, E44, E52, G11. Résumé: Le canal du crédit bancaire amplifie les effets du canal traditionnel de la politique monétaire et met l.accent sur la structure et sur les frictions du marché financier, lesquels constituent les éléments qui déterminent de la dépense agrégée. L.objectif de cet article est d.analyser et de vérifier l.existence du canal du crédit bancaire en Colombie en estimant le modèle proposé par Michael Gibson en 1997, lequel utilise des régressions à seuil pour déterminer l.impact de la politique monétaire sur la demande agrégée. Les résultats obtenus ne permettent pas d.écarter l.existence d.un mécanisme de transmission pendant la période analysée, malgré le fait qu.il ne paraisse agir qu.à travers une politique monétaire restrictive. Mots clef: politique monétaire, mécanismes de transmission, canal du crédit bancaire, modèles à seuil. Classification JEL: C12, C52, E44, E52, G11.
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Tripier, Fabien. "Frictions de recherche sur les marchés financiers". Revue française d'économie XXVIII, n. 4 (2013): 15. http://dx.doi.org/10.3917/rfe.134.0015.
Testo completo
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Whitehall, Geoffrey, e Victoria Silva Sánchez. "In different states of indifference: movement, friction, and resistance". Relaciones Internacionales, n. 54 (24 ottobre 2023): 39–56. http://dx.doi.org/10.15366/relacionesinternacionales2023.54.002.
Testo completoAbstract (sommario):
. This article critically engages with the question of mobility in the study of international politics by centering the concept of resistance. It starts with the example of the Canadian Government blocking the Roxham Road irregular border crossing in March 2023 and Canadian officials arguing in favour of normalizing movement between the US/Canada. In general, the paper challenges the global state centric project of normalizing movement by arguing that resistance always comes first. As such, this challenge does not only ask who/what gets to move freely and when; it is centers the very resistances to normalizing movement that emerges from within and without movement itself. The paper has three sections: the first acknowledges that celebrating movement is important because it loosens the state centric study of international politics and sets borders, states, and migrants adrift in a sea of irregular movements. It creates a differential analysis of movement which I refer to as “differential encounters”. In the context of this article, recasting the state in the context of movement demands an engagement with Indigenous and migrant histories beyond the modern categories of immigrant or settler. It requires going beyond merely placing Indigenous peoples into other non-Indigenous migrations stories since it reproduces the colonial efforts to exceptionalize the immigrant experience in and through its universalization/provincialization. Such practical efforts to normalize movement allow the Canadian state to present itself as the apolitical and fixed arbiter of different movements and thereby displace the unceded mediating role inherent to Indigenous relationships to the land and its peoples. The second section shifts to an epistemological register of movements to recognize that celebrating movement can also depoliticize movements differences. Therefore, movement is not simply given; it is itself treated as diagnostic and productive by attending to the function of friction inside and between movements. Following the work of Anna Tsing, frictions are not only the product of movement but also the shapers and materializers of movement(s). They are the encounters that actualize, materialize, and define movements. They occur when movements interact, and they produce something new within the specific place-based context of differential encounters. Friction is becoming movement because nothing moves or matters without friction. This section “matters” the nine individuals, including two children, who lost their lives while being smuggled through the Akwesasne district of the St. Lawrence River, which straddles the US/Canada border. Their lives are mattered in and through the materialization of movements. Yet, in differential encounters, there can be no sovereign, disciplinary, or biopolitical accounting of bodies and lives: only frictions, movements, and resistances. These frictions both materialize and are material. They are historical and immediate. From macro to micro: the decision to deploy a particular technology is as significant as the reliability of an operation, machine, or equipment in the day to day. The political frictions between movements, as such, become the focus of studies which centre movement. To find politics one must move with resistance. To move with resistance is to open untoward frictions. Moving with resistance politicizes those very movements and frictions that have become regularized and/or normalized. The final section argues that despite the emancipatory narrative attached to privileging ontological and epistemological approaches, resistance should always be situated as a generative force that comes first. This section uses the four-part documentary series Thunder Bay (2023), by Ryan McMahonm, the award winning Anishinaabe journalist, to investigates forms of resistance in Thunder Bay, Ontario, which sits at the head of Lake Superior. The history of Thunder Bay is defined by Indigenous/settler relations —a complex of trade, employment, governance, policing, and personal frictions —and amass into the colonial frictions of the city. Thunder Bay’s purpose has not changed. It continues to exist in order to control, extract and extinguish Indigenous futures. While the documentary challenges the audience to see Thunder Bay as both an exceptional crisis in policing and as an exemplar case of continued Canadian colonialism, McMahon’s series also helps the effort in this paper to rethink the concept of resistance in the context of movement and friction. To think about resistance as coming first, the concept of resistance itself must be redefined, not as opposition or reaction, but as an enduring medium of escalation and indifference. Resisting colonialism cannot erase its constitutive frictions; colonialism is a movement responding to already existing resistance, friction and movement. As such, the colonial project remains intact, and escalation adds new opportunities for the state to escalate in turn. Thunder Bay laments that, despite the inspiring efforts of individuals and movements, Indigenous resistance is reduced to new and further instances of friction that keep the wheels of the Canadian state turning. Resistance in movement is a prior interplay of indifferently releasing one movement and politically escalating other emergent movements that resurface in the wake. The article puts special attention to the concept of indifference since “to indiffer” break or turn away from the modern state form, is to actively dismantle those escalatory forces of resistance and friction captured by the state’s ambition to appear static. However, just as resistance has come to mean opposition to movement and lost its political value, indifference has also been cast as a static apolitical form of being. Again, just as resistance escalates, it also indiffers. To indiffer evokes differing, but not in ways that contribute to a particular movement’s escalation or friction. Instead, indiffering releases, liberates, suspends both escalation and friction. This does not mean that indifference has no relationship with escalation or friction in the abstract. To indiffer is an active unattending to a movement’s particular escalation and friction. It is resisting, releasing, and forgetting and generating new frictions and movements. Yet indifference is not innocent —it is not only a weapon of the weak. The state also practices indifference. The indifferent state actively uncares about Indigenous lives because its own future requires unmaking of Indigenous future horizons. This article suggests that if resistance is no longer believed to be a willful action of the liberal subject, and resistance always comes in advance, then the frictions that unfold as movements inevitably unmap geographies of the state and open untoward irregular movements and futures.
6
Lesourne, Jacques. "Le marché et l’auto-organisation". Économie appliquée 38, n. 3 (1985): 663–701. http://dx.doi.org/10.3406/ecoap.1985.4057.
Testo completoAbstract (sommario):
The paper presents an on-going research on the occurrence of self-organization as a consequence of market dynamics. After an analysis of a labour market on which workers look for jobs, negociate with firms and adapt, as well as the latters, their requirements through time, the paper introduces successively information constraints, friction costs, location costs, information costs, then examines more complex set ups. In one of them, workers may acquire new professional abilities when employed by given firms, the structure of the future labour supply being thus randomly generated by market dynamics. It is shown in the conclusion that a market may be considered as an autopoïetic system.
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Renkin, Hadley Z. "Perverse Frictions: Pride, Dignity, and the Budapest LGBT March". Ethnos 80, n. 3 (5 marzo 2014): 409–32. http://dx.doi.org/10.1080/00141844.2013.879197.
Testo completo
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Vadacca, Luigi. "The Altotiberina Low-Angle Normal Fault (Italy) Can Fail in Moderate-Magnitude Earthquakes as a Result of Stress Transfer from Stable Creeping Fault Area". Geosciences 10, n. 4 (16 aprile 2020): 144. http://dx.doi.org/10.3390/geosciences10040144.
Testo completoAbstract (sommario):
Geological and geophysical evidence suggests that the Altotiberina low-angle (dip angle of 15–20 ° ) normal fault is active in the Umbria–Marche sector of the Northern Apennine thrust belt (Italy). The fault plane is 70 km long and 40 km wide, larger and hence potentially more destructive than the faults that generated the last major earthquakes in Italy. However, the seismic potential associated with the Altotiberina fault is strongly debated. In fact, the mechanical behavior of this fault is complex, characterized by locked fault patches with a potentially seismic behavior surrounded by aseismic creeping areas. No historical moderate (5 ≤ Mw ≤ 5.9) nor strong (6 ≤ Mw ≤ 6.9)-magnitude earthquakes are unambiguously associated with the Altotiberina fault; however, microseismicity is scattered below 5 km within the fault zone. Here we provide mechanical evidence for the potential activation of the Altotiberina fault in moderate-magnitude earthquakes due to stress transfer from creeping fault areas to locked fault patches. The tectonic extension in the Umbria–Marche crustal sector of the Northern Apennines is simulated by a geomechanical numerical model that includes slip events along the Altotiberina and its main seismic antithetic fault, the Gubbio fault. The seismic cycles on the fault planes are simulated by assuming rate-and-state friction. The spatial variation of the frictional parameters is obtained by combining the interseismic coupling degree of the Altotiberina fault with friction laboratory measurements on samples from the Zuccale low- angle normal fault located in the Elba island (Italy), considered an older exhumed analogue of Altotiberina fault. This work contributes a better estimate of the seismic potential associated with the Altotiberina fault and, more generally, to low-angle normal faults with mixed-mode slip behavior.
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Ramirez-Zamudio, Aldo, e Elmer Sanchez Davila. "Lessons from COVID’S Vaccination: External-Internal Frictions and Efficiency". Vaccines 11, n. 2 (22 gennaio 2023): 248. http://dx.doi.org/10.3390/vaccines11020248.
Testo completoAbstract (sommario):
This paper explores some economic variables that determine the emerging of new COVID-19 variants and the determinants of vaccination advances in 108 countries during a quarterly period from March 2020 to March 2022. We found that more people being fully vaccinated and more education (measured as schooling years) decrease the probability of the emergence of new COVID-19 variants, but more crowded cities and higher percentages of urban population increase that probability. Furthermore, we found that the percentage of fully vaccinated people depends positively on the country’s preparation to respond to a health crisis, educational levels, and the index of economic complexity (which measures how diverse in the production of goods and services a country is and the level of its infrastructure), and it depends negatively on the percentage of rural populations (which makes vaccination more difficult).
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Smith, Roderick A. "Kenneth Langstreth Johnson. 19 March 1925 — 21 September 2015". Biographical Memoirs of Fellows of the Royal Society 62 (gennaio 2016): 247–65. http://dx.doi.org/10.1098/rsbm.2016.0012.
Testo completoAbstract (sommario):
Kenneth Johnson, born in Barrow in 1925, studied mechanical engineering at Manchester during World War II. After some years in industry and an early appointment back in Manchester, he spent most of his academic career teaching and researching at the Engineering Department of Cambridge University. He was also a long-serving Fellow of Jesus College. He was renowned for the insightful analysis of meticulous experiments in contact mechanics. He was widely acknowledged as the doyen of this area, particularly after the publication of his seminal work of the same name. His major publications included topics in friction and wear, rheology and lubrication, rolling contact and adhesion. Important applications of his insights included the prediction of corrugations and cracks in railway lines. He was gratified when, after many years of dormancy, his ideas in adhesion were used by others to explain the climbing behaviours of insects and other small animals with soft feet. He was a devoted family man, characterized by warm personal qualities that won him many friends around the world.
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Alcantara, Christopher. "Ideas, Executive Federalism and Institutional Change: Explaining Territorial Inclusion in Canadian First Ministers' Conferences". Canadian Journal of Political Science 46, n. 1 (marzo 2013): 27–48. http://dx.doi.org/10.1017/s0008423913000152.
Testo completoAbstract (sommario):
Abstract.Official participation in Canadian First Ministers' Conferences has long been exclusive to federal and provincial first ministers. In March 1992, however, the membership of this intergovernmental arena was expanded permanently to include territorial premiers. Using the tools of historical institutionalism and drawing upon relevant literature and eleven elite interviews with former first ministers and senior civil servants, this paper seeks to explain why this instance of incremental institutional change occurred. It finds that significant friction between the institutional and ideational layers of the Canadian federation during a period of mega-constitutional reform allowed federal, provincial and territorial actors to draw upon ideas about democracy and the political and constitutional maturation of the territorial North to expand permanently the membership of First Ministers' Conferences.Résumé.Pendant longtemps, seuls les premiers ministres fédéral et provinciaux étaient admis officiellement à la conférence des premiers ministres du Canada. Toutefois, en mars 1992, ce sommet intergouvernemental était élargi en permanence de façon à accueillir les premiers ministres des territoires. À l'aide des outils de l'institutionnalisme historique, et en tirant parti de la documentation pertinente ainsi que de 11 entrevues menées auprès d'un groupe sélect d'ex-premiers ministres et de hauts fonctionnaires, cet article tente d'expliquer pourquoi nous avons assisté à un tel degré de changement constitutionnel. Nous en concluons que d'importantes frictions entre les niveaux institutionnel et idéationnel de la fédération canadienne au cours d'une période de réforme mégaconstitutionnelle ont permis aux acteurs fédéraux, provinciaux et territoriaux de s'inspirer d'idées portant sur la démocratie et sur le processus de maturation politique et constitutionnel du Nord territorial afin d'accroître en permanence le nombre de participants aux conférences des premiers ministres.
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Mathur, Ajit. "Rashtriya Seva Samsthan". Vikalpa: The Journal for Decision Makers 13, n. 3 (luglio 1988): 81–84. http://dx.doi.org/10.1177/0256090919880311.
Testo completoAbstract (sommario):
(In the January-March 1988 issue, Vikalpa carried a Diagnostic case entitled “Rashtriya Seva Samsthan.” The case was about a young executive, Victor D'Cunha, chosen to head the data processing cell in a newly set up administrative office of a public sector organization. D'Cunha runs into political problems in implementing the planning- and monitoring system. He is transferred out of that location as a response to the frictions that develop. Frustrated, the young officer quits. Ajit Mathur gives his reactions– Ed.)
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Luzardo-Luna, Ivan. "Labour frictions in interwar Britain: industrial reshuffling and the origin of mass unemployment". European Review of Economic History 24, n. 2 (26 febbraio 2019): 243–63. http://dx.doi.org/10.1093/ereh/hez001.
Testo completoAbstract (sommario):
Abstract This article estimates the matching function of the British labour market for the period of 1921–1934. Changes in matching efficiency can explain both employment resilience during the Great Depression and the high structural unemployment throughout the interwar period. Early in the 1920s, matching efficiency improved due to the development of the retail industry. However, the econometric results show a structural break in March 1927, related to a major industrial reshuffling that reduced the demand for workers in staple industries. Since these industries were geographically concentrated, there was an increase in the average distance between the unemployed and vacancies, and matching efficiency declined.
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Singh, Amit. "Technology Focus: Formation Damage (March 2023)". Journal of Petroleum Technology 75, n. 03 (1 marzo 2023): 83–84. http://dx.doi.org/10.2118/0323-0083-jpt.
Testo completoAbstract (sommario):
Identification, prevention, and remediation of formation damage during the life cycle of oil and gas wells are key for our industry to allow wells to perform to their full potential. Increased awareness of potential damage mechanisms along with improvements in laboratory testing equipment and methodologies have proven to be instrumental in efficient prevention and remediation of formation damage in production and injection wells in conventional reservoirs. While the ongoing technical studies and technology developments in the area of formation damage are heavily focused on key damage-mechanism scenarios during drilling and production, such as drilling-fluid-induced damage, scaling, clay swelling, fines migration, and incompatibility of fluid/fluid and fluid/rock in conventional sandstone and carbonate reservoirs, there are new research activities and increased applications of learnings in low-permeability unconventional reservoirs and carbon capture and storage (CCS). In low-permeability unconventional reservoirs, hydraulic fracturing has proven instrumental for economic and successful development. Injection of a large volume of fracturing fluid water is necessary to place the required quantity of proppant to generate and maintain fracture conductivity, thereby increasing the risk of fracturing-fluid-induced formation damage. New laboratory studies and field trials to select suitable preventive additives in fracturing fluid and optimize flowback processes are being deployed to prevent formation damage not only from gelling materials, friction-reducer chemicals, and water blockage but also from scaling and paraffin during production. Identification and prevention of formation-damage mechanisms affecting injectivity during CO2 injection in subsurface for CCS and CO2 enhanced oil recovery are critical. Enjoy the papers chosen this year, some of which highlight my comments and the innovation and successes achieved by our industry in identification, prevention, and remediation of formation damage in conventional reservoirs, which is expected to bring success in area of unconventional-reservoir development and carbon reduction. Recommended additional reading at OnePetro: www.onepetro.org. IPTC 22543 Formation Damage in the Hollín Sandstone: Diagnosis, Evaluation, and Stimulation Practices From Laboratory to Field Implementation, Sacha Field, Ecuador by Alvaro Izurieta, Halliburton, et al. SPE 208852 Understanding Fluid Exchange as Screens Are Run in Hole—Mitigation of Formation and Completion Damage Risks by Michael Byrne, Axis, et al. SPE 210763 Near-Wellbore Damage Associated With Formation Dry-Out and Fines Migration During CO2 Injection by Liam Alchin, The University of Adelaide, et al.
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Helfrich, Vincent, e Fanny Romestant. "Achat public et développement durable entre compatibilités et frictions de paradigmes et de pratiques : le cas de l’industrie du transport ferroviaire". Management international 20, n. 1 (4 maggio 2018): 78–93. http://dx.doi.org/10.7202/1045357ar.
Testo completoAbstract (sommario):
Cet article se propose d’analyser, selon deux niveaux de lecture, le degré de compatibilité entre les enjeux développement durable et l’utilisation des achats publics au sein des marchés de l’Union Européenne. Le premier niveau est d’ordre conceptuel, avec un questionnement de la concordance possible entre les principes théoriques, au coeur du développement durable, d’un côté et de l’idéologie européenne, sous-jacente au fonctionnement des achats publics, de l’autre. Le second niveau est d’ordre pragmatique, en interrogeant le degré d’intégration possible du développement durable dans les marchés publics. Nous appuierons nos réflexions sur le cas de l’industrie ferroviaire, à l’aide des matériaux issus d’une recherche-intervention menée au sein d’une entreprise industrielle dans ce secteur.
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Løvholt, F., G. Kaiser, S. Glimsdal, L. Scheele, C. B. Harbitz e G. Pedersen. "Modeling propagation and inundation of the 11 March 2011 Tohoku tsunami". Natural Hazards and Earth System Sciences 12, n. 4 (16 aprile 2012): 1017–28. http://dx.doi.org/10.5194/nhess-12-1017-2012.
Testo completoAbstract (sommario):
Abstract. On 11 March 2011 the Tohoku tsunami devastated the east coast of Japan, claiming thousands of casualties and destroying coastal settlements and infrastructure. In this paper tsunami generation, propagation, and inundation are modeled to hindcast the event. Earthquake source models with heterogeneous slips are developed in order to match tsunami observations, including a best fit initial sea surface elevation with water levels up to 8 m. Tsunami simulations were compared to buoys in the Pacific, showing good agreement. In the far field the frequency dispersion provided a significant reduction even for the leading wave. Furthermore, inundation simulations were performed for ten different study areas. The results compared well with run-up measurements available and trim lines derived from satellite images, but with some overestimation of the modeled surface elevation in the northern part of the Sanriku coast. For inundation modeling this work aimed at using freely available, medium-resolution data for topography, bottom friction, and bathymetry, which are easily accessible in the framework of a rapid assessment. Although these data come along with some inaccuracies, the results of the tsunami simulations suggest that their use is feasible for application in rapid tsunami hazard assessments. A heterogeneous source model is essential to simulate the observed distribution of the run-up correctly, though.
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Jadhav, P. D., S. V. Gupta, B. N. Patil, P. H. Bakane, S. M. Ghawade e S. D. Jadhao. "Study on the Engineering Properties of Whole Garlic Bulbs and Garlic Cloves for Effective Design of Processing Machinery". International Journal of Bio-resource and Stress Management 15, Oct, 10 (23 ottobre 2024): 01–07. http://dx.doi.org/10.23910/1.2024.5698.
Testo completoAbstract (sommario):
The present experiment was conducted from February, 2024 to March, 2024 at the Department of Agricultural Process Engineering, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra, India to investigate the various engineering properties of garlic bulbs and garlic cloves. The engineering properties viz., physical, gravimetric and frictional properties, were studied for whole garlic bulbs and garlic cloves by considering their importance in developing different agricultural and post-harvest processing machinery. The weight 11.41 g, length (polar diameter) 33.69 mm, width (equatorial diameter) 29.51 mm, thickness 27.58 mm, arithmetic mean diameter 30.26 mm, geometric mean diameter 30.10 mm, shape index 0.88, sphericity 0.90, surface area 63.05 cm2, cross-sectional area 53.75 cm2, bulk density 449.50 kg m-3, true density 930.45 kg m-3, porosity 51.69%, moisture content 56.70% and angle of repose of garlic bulb 50.54° were obtained. Similar properties were determined for garlic cloves. The L, a and b values for garlic bulb and garlic cloves were 82.95, 0.23, 10.66 and 74.42, 0.28, 12.48, respectively. The water activity of garlic was found to be 0.98±0.02. The coefficient of friction of the garlic bulb and garlic cloves was measured for the selected testing surfaces such as mild steel (MS), stainless steel (SS), wood, glass and fiberglass which was considered in hopper design. The compression force required to loosen the cloves from the garlic bulb was calculated as 61 N. By integrating these engineering properties into the design process, manufacturers can develop equipments or machineries that are more efficient, durable and capable of producing high-quality garlic products.
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Wang, Xiuying, Yuancang Ma, Fu Li, Qi Chen, Shujiao Sun, Honglu Ma e Rui Zhang. "Gap Filling Method and Estimation of Net Ecosystem CO2 Exchange in Alpine Wetland of Qinghai–Tibet Plateau". Sustainability 15, n. 5 (6 marzo 2023): 4652. http://dx.doi.org/10.3390/su15054652.
Testo completoAbstract (sommario):
The net ecosystem CO2 exchange (NEE) and water and energy fluxes at the alpine ecosystem level were obtained through the eddy covariance technique in an alpine wetland of the Longbao Region, Qinghai–Tibet Plateau. Our research used the NEE as the research object combined with meteorological factors. The NEE prediction model was constructed using Reddyproc and machine learning. Moreover, the effects of the data and features on the models and the selection of the model parameters were discussed. The results revealed the following information: (1) After removing the NEE outliers according to the friction wind speed thresholds of the different seasons, the NEE interpolation accuracy (R2) reached 0.65. Additionally, the NEE data dispersion decreased after removing the outliers, and the data quality improved effectively. (2) The decision coefficients (R2) of the eight kinds of combined machine learning algorithm models varied from 0.22 to 0.62, and the root mean square error (RMSE) ranged from 2.10 to 2.99 μmol s−1 m−2. Additionally, the multilayer perceptron (MLP) model had the best stability and the best interpolation effect. (3) There was a seasonal difference between the estimated values of Reddyproc and the estimated values of MLP. The monthly mean values of January, February, March, and October were lower than the monthly mean values of the latter, while the monthly mean values from April to September were higher than the monthly mean values of the latter, indicating that the prediction of the machine learning algorithm tends towards the carbon source in the cold season (nongrowing season) and tends towards the carbon sink in the warm season (growing season). (4) Reddyproc detected the outliers through the relationship between the night NEE and frictional wind speed, which made it possible to accurately estimate the nighttime flux under the condition of determining the threshold of the night frictional wind speed, thus obtaining a better NEE estimate with fewer input parameters. Before the training and prediction of the MLP model, the NEE was detected for the time series outliers, and the prediction accuracy was significantly improved, indicating that the elimination of the time series outliers is essential for NEE model training and further indicating that the understanding of the potential mechanism of the NEE is of great significance for the prediction model.
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Gallego, Francisco A., e Jose A. Tessada. "Corrigendum to “Sudden stops, financial frictions, and labor market flows: Evidence from Latin America” [J. Dev. Econ. 97(2), (March 2012)]". Journal of Development Economics 109 (luglio 2014): 56. http://dx.doi.org/10.1016/j.jdeveco.2014.03.008.
Testo completo
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Papy, Jacques. "L’échange de droits d’émission de gaz à effet de serre sous la loupe de l’analyse économique du droit". Les Cahiers de droit 54, n. 4 (2 dicembre 2013): 851–907. http://dx.doi.org/10.7202/1020654ar.
Testo completoAbstract (sommario):
Le Québec a jeté, en 2012, les bases du système de plafonnement et d’échange de droits d’émission de gaz à effet de serre. Le système pourrait, à terme, constituer l’un des maillons d’un marché commun du carbone à l’échelle de l’Amérique du Nord. Celui-ci appartient cependant à une catégorie d’instruments économiques de protection de l’environnement encore peu connue des juristes. L’exploration de l’architecture de cet instrument et l’examen des enjeux qui le traversent sont donc d’actualité. Pour ce faire, l’auteur propose une ébauche de modélisation, à la lumière de l’analyse économique du droit, de l’architecture de ce type de régime, en s’attardant plus particulièrement aux problèmes posés par l’organisation de l’échange de droits d’émission. La modélisation permet d’éclairer le rapport théorique étroit que le droit entretient avec l’efficacité économique lorsque le régulateur recourt au marché afin d’assurer la protection de l’environnement. Le modèle proposé met ainsi en lumière, de manière générale, les points de friction qui sont susceptibles de survenir aux différentes étapes de l’échange de droits d’émission et qui peuvent faire obstacle à son efficacité économique. Le modèle permet également de tirer quatre recommandations préliminaires qui pourraient être pertinentes pour le régulateur, à l’occasion de l’élaboration de la mise en oeuvre du système québécois de plafonnement et d’échange de droits d’émission de gaz à effet de serre.
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Chen, Jui-Lung. "Discussion on the Impact of Sino-US Trade War on Taiwanese Manufacturing". International Journal of Business and Management 14, n. 7 (8 giugno 2019): 70. http://dx.doi.org/10.5539/ijbm.v14n7p70.
Testo completoAbstract (sommario):
When US President Donald Trump signed the Section 301 Investigation in March 2018, the Sino-US trade war intensified, exerting a great impact on the global economy. The Trump Administration recently has piled up the economic and trade pressure on China, while China seeks to resort to the WTO dispute settlement mechanism and break the siege imposed by the trade war through the "Belt and Road Initiative". US launched a trade war against China due mainly to the huge trade deficit with China, and the trade frictions between the U.S. and China have caused turbulence on the Asian and global industrial chains. Therefore, by analyzing the recent trade conflicts between the U.S. and China and the responses given by both respectively, this paper explores the possible impact on Taiwan's manufacturing and its potential response.
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Rizwana.K, Anitha.A, Ramana.K e Kamalakannan.M. "Efficacy of Positional Release Therapy Versus Deep Transverse Frictional Massage on Quadratus Lumborum Strain among IT Workers". Indian Journal of Physiotherapy & Occupational Therapy - An International Journal 18 (21 gennaio 2024): 772–76. http://dx.doi.org/10.37506/k1xrsj74.
Testo completoAbstract (sommario):
Background: The study was designed to inspect the effectiveness of Positional Release Therapy (PRT) and DeepTransverse Frictional Massage (DTFM) on Quadratus Lumborum Strain.Purpose: The purpose of this study is to compare the efficacy of Positional Release and Deep Transverse FrictionalMassage for Quadratus Lumborum.Materials and Methods: Sixty subjects with Trigger Points in quadratus lumborum muscle were divided randomlyinto two equal groups. Group “PRT” received Positional Release Therapy five times/week while Group “DTFM”received Deep Transverse Frictional Massage five times/week for two weeks. Numeric Pain Rating Scale (NPRS),Universal Goniometer were used to evaluate subjects at two intervals (Pre-Treatment and Post-Treatment).Theentire process was performed from November 2022 to March 2023.Result: The results of the study revealed that both the interventions were effective but in terms of superiority PRTgave a significant result than DTFM.Conclusion: Based on the study results, it was concluded that PRT was found to be more effective for the treatmentof Quadratus Lumborum strain.
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Levy, Phillip D., David C. Hile, Lisa M. Hile e Michael A. Miller. "A Prospective Analysis of the Treatment of Friction Blisters with 2-Octylcyanoacrylate". Journal of the American Podiatric Medical Association 96, n. 3 (1 maggio 2006): 232–37. http://dx.doi.org/10.7547/0960232.
Testo completoAbstract (sommario):
Early military investigations of blister treatment using tissue adhesives have shown promise, finding that these agents provide pain relief, prevent infection, and allow continuation of recruit training. A trial was conducted to compare a 2-octylcyanoacrylate treatment with military standard therapy. Patients were recruited during foot evaluation at the end of a 10-km military road march. Seventy-five patients were screened, and 51 were enrolled. Twenty-six patients received 2-octylcyanoacrylate and 25 received standard treatment. A total of 80 blisters were treated (40 in each group). The mean (SD) blister size in the 2-octylcyanoacrylate group was 12.7 (6.2) mm and in the standard group was 12.0 (5.7) mm. There were no statistically significant differences in any of the baseline variables. Baseline and repeated-measures visual analog scale scores demonstrated no statistically significant differences in initial or repeat pain scores. Both groups showed a similar change across time, with a nonsignificant trend toward improvement in the standard therapy group at 10 min (28.5 versus 24.9) and in the 2-octylcyanoacrylate group at 3 days (42.9 versus 50.1). Mean Likert scores were similar, indicating no difference in patient satisfaction. Time to resumption of normal activity was similar, with one patient in each group unable to return to activity at the time of follow-up. There was a trend toward an increased proportion of patients in the 2-octylcyanoacrylate group who were able to return to normal activity within 48 hours, but this did not reach statistical significance. 2-Octylcyanoacrylate was associated with a greater degree of procedural discomfort. No infected blisters were noted in either group. (J Am Podiatr Med Assoc 96(3): 232–237, 2006)
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Ripka, S., H. Lind, M. Wangenheim, J. Wallaschek, K. Wiese e B. Wies. "Investigation of Friction Mechanisms of Siped Tire Tread Blocks on Snowy and Icy Surfaces". Tire Science and Technology 40, n. 1 (1 marzo 2012): 1–24. http://dx.doi.org/10.2346/1.3684409.
Testo completoAbstract (sommario):
Abstract REFERENCE: S. Ripka, H. Lind, M. Wangenheim, J. Wallaschek, K. Wiese, and B. Wies “Investigation of Friction Mechanisms of Siped Tire Tread Blocks on Snowy and Icy Surfaces,” Tire Science and Technology, TSTCA, Vol. 40, No. 1, January–March 2012, pp. 1–24. ABSTRACT: Due to general safety reasons and an increasing individual demand on more traffic safety, winter tires have become more and more important. This evolution results in a rising requirement of the customers concerning the tire performance on the one hand, and the effort of the tire industry to improve the tire traction performance on snow and ice on the other hand. To engineer winter tires in an effective way, the friction influencing factors as well as the contact mechanics should be well known. Normally the design and development of tires is strongly based on vehicle tests, but in modern tire development processes the simulation as well as the experimental investigation of tires and tire components in the lab have become more popular. This strategy plays an especially important role for reducing the time of development cycles but also the development costs. With simulation and experiments in lab, new challenges come up which have to be solved. Lab experiments compete with totally different problems: First of all, the environmental influences like temperature and humidity have to be controlled. Furthermore, the test tracks used inside must be comparable to the proving ground outside, hence the properties of snow and ice have to be investigated in detail. Therefore not only is it very important to understand the formation of snow and ice, but also to find characteristics of both materials which can be identified and measured with mobile measurement devices outside on the test track and inside in the lab. Within this publication a general overview of the tire tread block test method as well as the test rig, which are used for identifying relevant tread block friction mechanisms on snow and ice, will be given. The results of the measurement will be shown and the acting friction phenomena will be explained.
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Nauvarian, Demas, e Filasafia Marsya Ma'rifat. "From Friction to Acceleration: China’s Ambition for a Post-Pandemic Tianxia World Order". Global South Review 3, n. 1 (16 febbraio 2023): 62. http://dx.doi.org/10.22146/globalsouth.69759.
Testo completoAbstract (sommario):
This paper explores the relation between the Covid-19 pandemic and China’s peaceful rise. In March 2020, the Covid-19 virus outbreak was declared by World Health Organization (WHO) as a global pandemic that knows no boundaries. While China received an enormous spotlight for being the ground-zero of the pandemic, China has managed to control the pandemic effectively. Not only that, China has also even been able to help other countries by providing Covid-19 assistance to other countries in need. More significantly, however, China was in a unique position when the pandemic hit—it was in a critical period for its rising era. China’s rise has been framed as a ‘peaceful rise’ (heping jueqi). On the other hand, the pandemic forced China to re-think its national power usage while still striving to achieve an idealized order of Tianxia—all-under-heaven. This research analyses how China’s pandemic cooperation is utilized in a greater framework of peaceful rise to accelerate the establishment of Tianxia world order. This research argues that the pandemic served as a critical juncture for the status-quo liberal international order, and China took the opportunity to indirectly disrupt the order. This is evident through two main pillars of China’s pandemic cooperation: (1) asserting self-reliance by strengthening national response; (2) establishing cooperation to put China as a ‘middle kingdom.’ This research concludes that China, in some ways, successfully transform the pandemic from friction to an acceleration factor for its peaceful rise.
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Saburin, Dmitry S., e Tatiana G. Elizarova. "Modelling the Azov Sea circulation and extreme surges in 2013-2014 using the regularized shallow water equations". Russian Journal of Numerical Analysis and Mathematical Modelling 33, n. 3 (26 giugno 2018): 173–85. http://dx.doi.org/10.1515/rnam-2018-0015.
Testo completoAbstract (sommario):
Abstract A new model for calculation of circulation in shallow water basins is created based on the shallow water equations taking into account the Coriolis force and quadratic friction on the bottom. Wind effects are taken into account as forcing. The main feature of the model is a new numerical method based on regularized shallow water equations allowing one to construct the simple and sufficiently accurate numerical algorithms possessing a number of advantages over existing methods. The paper provides a detailed description of all construction steps of the model. The developed model was implemented for the water area of the Azov Sea. The paper presents the modelling of extreme surges in March 2013 and September 2014, the results of calculations are compared with observation data of hydrometeorological stations in Taganrog and Yeysk.
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Terzidis, George. "Discussion of “Simple and Accurate Friction Loss Equation for Plastic Pipe” by R. D. von Bernuth (March/April, 1990, Vol. 116, No. 2)". Journal of Irrigation and Drainage Engineering 118, n. 3 (maggio 1992): 501–4. http://dx.doi.org/10.1061/(asce)0733-9437(1992)118:3(501.2).
Testo completo
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Chen, Yifei, e Ye Li. "Analysis of Financial Risks and Stock Price Fluctuations of Enterprises under Sino-US Trade Friction". Highlights in Business, Economics and Management 21 (12 dicembre 2023): 389–93. http://dx.doi.org/10.54097/hbem.v21i.14494.
Testo completoAbstract (sommario):
In August 2017, the US initiated a Section 301 investigation against China’s trade practices, and on March 2018, the Office of the US Trade Representative accused China of unfair trade practices ranging from the forced transfer of technology to Chinese firms and intellectual property theft. For these reasons, the United States continues to impose tariffs on Chinese goods. China followed with a series of counter-measures, which became the beginning of a trade war between the two countries. It has a widespread influence on the global markets, international relations and the stability of national economies. This paper collects the stock price fluctuation and financial risk data of Intel before and after the trade war and makes a comparative analysis of the data. We explore how and when the US Trade War came and was framed. Besides China and USA, is there any other country that has had a substantial positive or negative impact from the US Trade War. Finally, we found that how the trade war affects the stock price and change the financial risk of the firms in China and the USA. According to research findings, the trade war had a negative impact on Internet stock prices and financial risks in both countries.
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Hagan, Maura E., e Dwight P. Sipler. "Combined incoherent scatter radar and Fabry-Perot interferometer measurements of frictional heating effects over Millstone Hill during March 7–10, 1989". Journal of Geophysical Research 96, A1 (1991): 289. http://dx.doi.org/10.1029/90ja02250.
Testo completo
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Tian, Rong, Xiaoyan Ma e Jianqi Zhao. "A revised mineral dust emission scheme in GEOS-Chem: improvements in dust simulations over China". Atmospheric Chemistry and Physics 21, n. 6 (22 marzo 2021): 4319–37. http://dx.doi.org/10.5194/acp-21-4319-2021.
Testo completoAbstract (sommario):
Abstract. Mineral dust plays a significant role in climate change and air quality, but large uncertainties remain in terms of dust emission prediction. In this study, we improved treatment of the dust emission process in a global 3-D chemical transport model (GEOS-Chem v12.6.0), by incorporating the geographical variation of aerodynamic roughness length (Z0), smooth roughness length (Z0s) and soil texture and by introducing the Owen effect and the formulation of the sandblasting efficiency α by Lu and Shao (1999). To investigate the impact of the modifications incorporated in the model, several sensitivity simulations were performed for a severe dust storm during 27 March to 2 April 2015 over northern China. Results show that simulated threshold friction velocity is very sensitive to the updated Z0 and Z0s field, with the relative difference ranging from 10 % to 60 % compared to the original model with a uniform value. The inclusion of the Owen effect leads to an increase in surface friction velocity, which mainly occurs in the arid and semi-arid regions of northwest China. The substitution of a fixed value of α assumed in the original scheme with one varying with friction velocity and soil texture based on observations reduces α by 50 % on average, especially over regions with sand texture. Comparisons of sensitivity simulations and measurements show that the revised scheme with the implementation of updates provides more realistic threshold friction velocities and PM10 mass concentrations. The performance of the improved model has been evaluated against surface PM10 observations as well as MODIS aerosol optical depth (AOD) values, showing that the spatial and temporal variation of mineral dust are better captured by the revised scheme. Due to the inclusion of the improvement, average PM10 concentrations at observational sites are more comparable to the observations, and the average mean bias (MB) and normalized mean bias (NMB) values are reduced from −196.29 µg m−3 and −52.79 % to −47.72 µg m−3 and −22.46 % respectively. Our study suggests that the erodibility factor, sandblasting efficiency and soil-related properties which are simply assumed in the empirical scheme may lack a physical mechanism and spatial–temporal representativeness. Further study and measurements should be conducted to obtain a more realistic and detailed map of these parameters in order to improve dust representation in the model.
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Tang, Chi-Chia, Han Xu, Lupei Zhu, Rong Huang e Yinhe Luo. "Detecting repeating aftershocks in the Three Gorges Reservoir region, Central China". Geophysical Journal International 221, n. 2 (29 gennaio 2020): 1402–11. http://dx.doi.org/10.1093/gji/ggaa049.
Testo completoAbstract (sommario):
SUMMARY Slippage on a deep fault, which cannot be directly measured, can be inferred from repeating earthquakes. Here, we use a matched filter technique (MFT) to detect missing earthquakes near the Xiannvshan fault in the Three Gorges Reservoir region of Central China. We detected 13 repeating aftershock sequences (RASs) containing 107 events after a Ms 4.4 local earthquake that occurred on 26 March 2014. The RASs occurred in the vicinity of the Ms 4.4 main shock hypocentre and were concentrated within a depth range of 4–7 km. The short-term slip rates estimated from these RASs varied from ∼0.001 to 0.31 mm d–1. The slip rates of the RASs followed an approximately logarithmic decay with RAS duration, suggesting that the deep Xiannvshan fault behaviour tended to follow the logarithmic velocity-strengthening friction law. Relatively high-stress RAS events seemed to influence the occurrence of other RAS events whereas we found no evidence that high-stress nearby events, including a Ms 4.6 local earthquake that occurred on 29 March 2014, triggered the RAS events. We suggest that the fault stress change caused by the Ms 4.4 main shock played a role in triggering the RAS events. Our results demonstrate that the MFT can effectively help identify repeating aftershocks, which could help decipher fault zone rheology.
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Qasim, Ayad F., Rasha K. Sabri e Roa’a M. Younis. "Effect of Air Pollutants on Rain Water Characteristics in Hammam Al-Aleel District/ Al-Erej Village South of Mosul City". Tikrit Journal of Engineering Sciences 19, n. 2 (30 giugno 2012): 1–12. http://dx.doi.org/10.25130/tjes.19.2.09.
Testo completoAbstract (sommario):
This study focused on Hammam Al-Aleel district/ Al-Erej village which is located south of Mosul city. This area has been suffering from spreading the air-pollutants resulted from the chimneys of Hammam Al-Aleel cement factories. Different areas were chosen for collecting samples of the rain water from December 2008 to March 2009.The study showed that rain-water is generally basic. The tests show an increase in ( EC, Mg+2, Ca+2, Cl-1, SO4-2 and NO-1), due to the air pollutants emitted from local industries. The concentration of heavy elements represented by Pb and Cd were high and this increase is due to the source of these elements from burning of the crude oil which is used in running the rotating kiln to produce the clinker in cement factory, In addition to the fuel used for running vehicle and the friction between tires and road.
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Aljber, Morhaf, Kaho Nogami, Jae-Soon Jeong, Jonathan Salar Cabrera e Han Soo Lee. "TSUNAMI MODELLING IN A BUILT-IN COASTAL ENVIRONMENT WITH ADAPTIVE MESH RIFINEMENT AND VARYING BOTTOM FRICTION". Coastal Engineering Proceedings, n. 37 (1 settembre 2023): 40. http://dx.doi.org/10.9753/icce.v37.management.40.
Testo completoAbstract (sommario):
The great Japan earthquake on March/11/2011provoked an extreme tsunami wave toward the northeastern Japanese coast. The tsunami inundation covered a wide range of territories stretching over 500 km2 and caused devastating influences that claimed more than 15,000 lives (Mori et al. (2011)). Miyagi Prefecture, the closest mainland to the epicentre, received massive tsunami waves that reached over 40 m in run-up height. Prasetyo et al. (2019) aimed to reproduce the tsunami wave inundation in Onagawa Town of Miyagi Prefecture by building a physical model using Hybrid Tsunami Open Flume in Ujigawa Open Laboratory (HyTOFU) at Kyoto University to study the inundation process by measuring the wave height and arrival time. For that purpose, two wave types were used, the (Pump-type) hydraulic bore, and the (Piston-type) solitary wave. Also, 2D and quasi-3D (Q3D) models were tested for their robustness and applied to emulate tsunami propagation in the complex coastal city model. In this study, we adopted adaptive mesh refinement (AMR) for its efficiency in tsunami modelling with Basilisk open-source flow solver for non-linear shallow water (Saint-Venant) equations and fully non-linear Boussinesq (Green-Naghdi) equations (Popinet (2015)). The numerical experiment was conducted to validate the model by comparing the wave height with the physical model experiment, the 2D, and Q3D model results by Prasetyo et al. (2019).
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Ahlm, L., E. D. Nilsson, R. Krejci, E. M. Mårtensson, M. Vogt e P. Artaxo. "Aerosol number fluxes over the Amazon rain forest during the wet season". Atmospheric Chemistry and Physics 9, n. 24 (15 dicembre 2009): 9381–400. http://dx.doi.org/10.5194/acp-9-9381-2009.
Testo completoAbstract (sommario):
Abstract. Number fluxes of particles with diameter larger than 10 nm were measured with the eddy covariance method over the Amazon rain forest during the wet season as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) campaign 2008. The primary goal was to investigate whether sources or sinks dominate the aerosol number flux in the tropical rain forest-atmosphere system. During the measurement campaign, from 12 March to 18 May, 60% of the particle fluxes pointed downward, which is a similar fraction to what has been observed over boreal forests. The net deposition flux prevailed even in the absolute cleanest atmospheric conditions during the campaign and therefore cannot be explained only by deposition of anthropogenic particles. The particle transfer velocity vt increased with increasing friction velocity and the relation is described by the equation vt = 2.4×10−3×u* where u* is the friction velocity. Upward particle fluxes often appeared in the morning hours and seem to a large extent to be an effect of entrainment fluxes into a growing mixed layer rather than primary aerosol emission. In general, the number source of primary aerosol particles within the footprint area of the measurements was small, possibly because the measured particle number fluxes reflect mostly particles less than approximately 200 nm. This is an indication that the contribution of primary biogenic aerosol particles to the aerosol population in the Amazon boundary layer may be low in terms of number concentrations. However, the possibility of horizontal variations in primary aerosol emission over the Amazon rain forest cannot be ruled out.
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de Felice, Giulio, Nihal Tutal e Nicolina Sciaraffa. "Geopolitical aspects of COVID-19 vaccines distribution". European Journal of Environment and Public Health 7, n. 3 (1 luglio 2023): em0132. http://dx.doi.org/10.29333/ejeph/12779.
Testo completoAbstract (sommario):
In December 2019, the Wuhan Municipal Health Commission (China) reported to the World Health Organization (WHO) a cluster of pneumonia cases with unknown aetiology in Wuhan City, Province of Hubei, China. In March 2020, WHO declared a pandemic. So began the spread of Sars-Cov-2 and the race to possible countermeasures. This article analyses the commercial relationships of the sale and purchase of vaccines as a measure of influence between different regions of the world. Taking all vaccines with a degree of global diffusion into account (Sputnik V, Russia; Sinovac, China; Sinopharm, China; Covishield, Oxford/AstraZeneca formulation, India; Johnson & Johnson, USA; Oxford/AstraZeneca, UK; Pfizer/BioNTech, USA; and Moderna, USA), the article examines the specific regions of distribution. The paper has two aims: Firstly, to understand if the vaccines’ distribution mirrors the geopolitical <i>status quo</i>. Secondly, to identify the territories potentially more capable of causing important, regional or global, geopolitical frictions. In order to do that, the article highlights regions with unipolar and multipolar geopolitical influences. Limitations and further possible developments of the work will be commented on in the conclusions.
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Asrowi, Ridho Hanan, Esmar Budi e Hadi Nasbey. "Development of the Wimshurst Machine as a Learning Media on Static Electricity Material for Junior High Schools". Current Steam and Education Research 1, n. 2 (31 dicembre 2023): 41–52. http://dx.doi.org/10.58797/cser.010201.
Testo completoAbstract (sommario):
This research aims to produce a learning media development product in the form of a Wimhurst machine teaching aid that can be used by teachers and students in the physics learning process. This media is expected to improve the knowledge and scientific thinking skills of grade 8 junior high school students in physics lessons on static electricity. This research was conducted in March-June 2014 at the Physics Department Laboratory, FMIPA-UNJ. The research carried out is research and development. This machine (the media) can show electric charge jumps directly from the friction between aluminum foil (sector) and brass as a rake. The results of the Wimhurst machine are learning media in the form of teaching aids that can help teachers in conveying material and can develop science process skills. The results of testing the Wimhurst machine teaching aids can attract students' interest in studying static electricity, so that students can easily understand the concept of static electricity.
37
Liana, Ulwiyah Wahdah Mufassirin, e Muhammad Arif. "The Impact of School Activities on Road Performance Using PTV Vissim Software Simulation". JSE Journal of Science and Engineering 3, n. 1 (31 luglio 2024): 23–31. http://dx.doi.org/10.30650/jse.v3i1.3991.
Testo completoAbstract (sommario):
Movement increases along with population growth and economic improvement each year. However, this is not supported by adequate transportation infrastructure, which can lead to congestion and traffic flow. The congestion of Samarinda during peak hours. One such location is Anang Hasyim Street, which has several schools along the road, including Cordova Elementary and Junior High School, SMPN 1, and SMAN 1 Samarinda. Traffic is evident during school hours, both morning and afternoon, along with an increase the number of vehicles and pedestrians. This situation leads to decline in the performance of the road segment. Road performance is a quantitative measurement that describes the conditions occurring on a road segment and serves as a parameter for road performance. This primary data such as road geometric data, traffic volume, and vehicle delays over a specific segment length. Traffic surveys were conducted over three days Monday, February 26, 2024, and Friday and Saturday, March 1-2, 2024. The survey were from 06:30-07:30 WITA,12:00-13:00 WITA, and 15:30-16:30 WITA. The analysis is based on PKJI 2023 and traffic flow simulation using PTV Vissim. The traffic results for 2024 shows the capacity of Anang Hasyim Street is 2968.154 pcu/hour, with the highest vehicle on Monday being 3079.75 pcu/hour and a degree of saturation 0.501 (LoS type A), and side friction of 500.8 incidents per hour. Meanwhile, the forecast for 2034 indicates the capacity remains 2968.154 pcu/hour, vehicle volume of 2202.83 pcu/hour, a degree of saturation 0.74 (LoS type B), and side friction of 563.33 incidents per hour.
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Walter, Bernard A., e James E. Overland. "The response of lead patterns in the Beaufort Sea to storm-scale wind forcing". Annals of Glaciology 17 (1993): 219–26. http://dx.doi.org/10.3189/s0260305500012878.
Testo completoAbstract (sommario):
With the use of time series of AVHRR imagery we examine a non-typical case of ice motion and lead pattern formation in the Beaufort Sea during a period of persistent southwesterly to southerly winds during 31 March-14 April 1991. Our goal is to suggest sea-ice rheologies through the use of satellite imagery. Ice motions were estimated by making a negative of the first image in a time sequence and combining it with a second image using a logical AND operation. Thus leads for the first day are white and those for the second day are black. For the period 31 March-5 April with westerly winds there was a slip line oriented southwest-northeast across the central Beaufort Sea and another slip line parallel to it 150 km to the north. Relative motion was 0.015 m s−1 across the slip lines. With southerly winds during 9-14 April the entire field of leads was advected to the north. Lead patterns are organized on a hierarchy of scales and the scales are a result of the particular magnitude of forcing by the atmosphere. Angles between diamond-shaped lead features with spacings of both 150 km and 10-20 km are approximately 30°, which as Erlingsson showed corresponds to an angle of internal friction of 15°. We provide an argument for the scale-invariant nature of the lead patterns and suggest that it may be possible to parameterize small-scale (less than tens of km) lead patterns.
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Walter, Bernard A., e James E. Overland. "The response of lead patterns in the Beaufort Sea to storm-scale wind forcing". Annals of Glaciology 17 (1993): 219–26. http://dx.doi.org/10.1017/s0260305500012878.
Testo completoAbstract (sommario):
With the use of time series of AVHRR imagery we examine a non-typical case of ice motion and lead pattern formation in the Beaufort Sea during a period of persistent southwesterly to southerly winds during 31 March-14 April 1991. Our goal is to suggest sea-ice rheologies through the use of satellite imagery. Ice motions were estimated by making a negative of the first image in a time sequence and combining it with a second image using a logical AND operation. Thus leads for the first day are white and those for the second day are black. For the period 31 March-5 April with westerly winds there was a slip line oriented southwest-northeast across the central Beaufort Sea and another slip line parallel to it 150 km to the north. Relative motion was 0.015 m s−1 across the slip lines. With southerly winds during 9-14 April the entire field of leads was advected to the north. Lead patterns are organized on a hierarchy of scales and the scales are a result of the particular magnitude of forcing by the atmosphere. Angles between diamond-shaped lead features with spacings of both 150 km and 10-20 km are approximately 30°, which as Erlingsson showed corresponds to an angle of internal friction of 15°. We provide an argument for the scale-invariant nature of the lead patterns and suggest that it may be possible to parameterize small-scale (less than tens of km) lead patterns.
40
Ahlm, L., E. D. Nilsson, R. Krejci, E. M. Mårtensson, M. Vogt e P. Artaxo. "Aerosol number fluxes over the Amazon rain forest during the wet season". Atmospheric Chemistry and Physics Discussions 9, n. 4 (19 agosto 2009): 17335–83. http://dx.doi.org/10.5194/acpd-9-17335-2009.
Testo completoAbstract (sommario):
Abstract. Number fluxes of particles with diameter larger than 10 nm were measured with the eddy covariance method over the Amazon rain forest during the wet season as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) campaign 2008. The primary goal was to investigate whether sources or sinks dominate the aerosol number flux in the tropical rain forest-atmosphere system. During the measurement campaign, from 12 March to 18 May, 60% of the particle fluxes pointed downward, which is a similar fraction to what has been observed over boreal forests. The particle transfer velocity vt increased with increasing friction velocity and the relation is described by the equation vt=2.4×10−3·u∗ where u∗ is the friction velocity. Upward particle fluxes often appeared in the morning hours and seem to a large extent to be an effect of entrainment fluxes into a growing mixed layer rather than primary aerosol emission. In general, primary aerosol emission had a limited impact on the total aerosol number population in this study, possibly because the measured particle number fluxes reflect mostly particles less than approximately 200 nm. The net deposition flux prevailed even in the absolute cleanest atmospheric conditions during the campaign and therefore cannot be explained only by deposition of anthropogenic particles. It seems that a significant contribution of secondary aerosol particles to the aerosol population is the most reasonable explanation for the net downward flux. This is an indication that secondary aerosol particles may dominate the aerosol number population in the Amazon boundary layer and that the contribution of primary aerosol particles may be low in terms of numbers. However, aerosol flux measurements should be repeated in a more remote area of the Amazon with less influence from anthropogenic sources before any final conclusions may be drawn.
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ADITYAWAN, MOHAMMAD BAGUS, MIN ROH, HITOSHI TANAKA, AKIRA MANO e KEIKO UDO. "INVESTIGATION OF TSUNAMI PROPAGATION CHARACTERISTICS IN RIVER AND ON LAND INDUCED BY THE GREAT EAST JAPAN EARTHQUAKE 2011". Journal of Earthquake and Tsunami 06, n. 03 (settembre 2012): 1250033. http://dx.doi.org/10.1142/s1793431112500339.
Testo completoAbstract (sommario):
The Great East Japan Earthquake of March 11, 2011 generated a massive tsunami wave that severely damaged coastal areas of Japan. Furthermore, the wave propagated into rivers, causing damage upstream far from shore. Videos recorded during this tsunami event were collected and analyzed to estimate the celerity of tsunami propagation in river and on the land. The result shows good comparison with estimation based on theoretical approaches that use water level measurement data. It was found that the tsunami celerity in river is approximately 25–30 km/h, and moved upstream with gradual deceleration. However, wave celerity on land was decreased significantly due to debris and dominant ground friction. The propagation trend in river mainstream and floodplain behaves differently in the location where the mainstream is not parallel to the embankment. Tsunami discharge and velocity in a river induced by tsunami wave were estimated based on continuity equation using the measured water level variation along the Sunaoshi River. The maximum estimated discharge is approximately 152 m3/s with the maximum velocity of 1.4 m/s.
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Islam, Farooq, Kanwal Arshad, Muhammad Asim Arif e Muhammad Salman Bashir. "POST ISOMETRIC HAMSTRING STRETCHING;". Professional Medical Journal 24, n. 08 (8 agosto 2017): 1224–31. http://dx.doi.org/10.29309/tpmj/2017.24.08.961.
Testo completoAbstract (sommario):
Objectives: Muscles and skeleton work together if any human being wants toroam around. If muscles and joint move to their full range then a free and purposeful action isachieved and goal is met for which movement was performed. If movement abnormality is seenthen its underlying cause can be tight muscle especially the hamstring in the lower extremity.Tight hamstring is quite common in normal individuals. This tightness is not desirable andneeds to be treated particularly when somebody needs to perform full range of motion withoutany difficulty. There are numerous choices to achieve this purpose. Different researchers usedifferent choices according to their own thinking. The main theme underlying this researchis to find out evidence based treatment option to treat the tight hamstring group. StudyDesign: randomized controlled trial. Place and Duration: different football clubs of Lahorefrom March 2015 to June 2015. Methodology: For this research two groups of football playerswere utilized. One group was selected for post isometric relaxation technique alone whileother group received a combination therapy containing post isometric relaxation and crossfrictional massage. Result: the p-value for the group 1 was 0.51 while for group 2 was 0.000.Conclusion: After conducting this research a conclusion was drawn that a combination ofpost isometric relaxation and cross frictional massage showed better results in releasing thetightness of hamstring than alone therapy. So a combination therapy comprising post isometricrelaxation and cross frictional massage was a better choice to treat tight hamstring.
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Ferrante, Angela, Ersilia Giordano, Francesco Clementi, Gabriele Milani e Antonio Formisano. "FE vs. DE Modeling for the Nonlinear Dynamics of a Historic Church in Central Italy". Geosciences 11, n. 5 (27 aprile 2021): 189. http://dx.doi.org/10.3390/geosciences11050189.
Testo completoAbstract (sommario):
The present research paper properly focuses on the dynamics and failure mechanisms of the masonry “Apennine Church” of Santissimo Crocifisso in Pretare, municipality of Arquata del Tronto in the province of Ascoli Piceno (Marche region, Central Italy). Such a peculiar structural type traditionally characterizes the intense seismic area of Central Italy, unfortunately almost totally damaged by the recent shock sequence of 2016. Advanced numerical modeling through discontinuous and continuous approaches were here utilized to have an insight into the dynamic properties and behavior of the structure under strong nonlinear dynamic excitations. In the discrete element approach, the non-smooth contact dynamics method, implemented in LMGC90©, was applied, adopting a full 3D detailed discretization. The church was schematized as an arrangement of rigid blocks, subjected to sliding by friction and perfect plastic collisions, with a null restitution coefficient. In the finite element approach, the concrete damaged plasticity model available in Midas FEA NX© was involved. This model allows reproducing the tensile cracking, the compressive crushing, and the degradation of the material under cyclic loads. Finally, the numerical analyses provided a valuable picture of the actual behavior of the church, thus giving useful hints for future strengthening interventions.
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Hamel, James V. "Re-evaluation of the 1941 Rock Slide at Brilliant Cut, Pittsburgh, Pennsylvania". Environmental and Engineering Geoscience 27, n. 3 (4 giugno 2021): 269–85. http://dx.doi.org/10.2113/eeg-d-20-00076.
Testo completoAbstract (sommario):
ABSTRACT On March 20, 1941, more than 110,000 yd3 (84,000 m3) of rock slumped from Brilliant Cut in Pittsburgh, Pennsylvania. Failure was triggered by water pressure buildup due to ice blockage of drainage outlets on the slope face. I investigated this slide as part of my Ph.D. research at the University of Pittsburgh in 1968–1969 and have continued to study it. Historical photographs discovered in 1997 provided new insights on the construction and failure of Brilliant Cut and led to this re-evaluation. In this paper, my 1968–1969 work is summarized and then additional geological and historical information is presented along with key observations from the historical photographs. These photographs reveal that slope excavation at Brilliant Cut in 1930–1931 removed lateral support, in turn initiating stress release and progressive failure that loosened or broke bedrock adjacent to the cut. This fractured rock mass remained marginally stable for a decade but then collapsed in March 1941. The 1941 failure was triggered by water held back in rock fractures by a frozen crust over talus and fractured rock on the slope face. A progressive failure mechanism by Brooker and Peck explains the behavior of Brilliant Cut from 1931 to 1941. Sliding Block stability analyses demonstrate the mechanism of progressive failure and suggest that friction angles were reduced gradually to near-residual values along the failure surface, with low water levels in the slope. With drainage blocked in 1941, a water level developed about 30 ft (9 m) above the basal failure surface to initiate the catastrophic failure. This water level is below that previously inferred to have existed at the time of failure.
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Liu, Song, Jia Xing, Shovan Kumar Sahu, Xiliang Liu, Shuchang Liu, Yueqi Jiang, Hongliang Zhang et al. "Wind-blown dust and its impacts on particulate matter pollution in Northern China: current and future scenarios". Environmental Research Letters 16, n. 11 (1 novembre 2021): 114041. http://dx.doi.org/10.1088/1748-9326/ac31ec.
Testo completoAbstract (sommario):
Abstract Northern China experienced two intense dust storms in March 2021, leading to reduced visibility and excessive particulate pollution. Understanding the cause of such extreme phenomena is important for further prevention. This study successfully reproduced the extreme dust storms using the Community Multiscale Air Quality model with refined bulk density of different soil types and improved spatial resolution. The wind-blown PM2.5 and PM10 are estimated to be around 15 and 120 μg m−3 in dust source areas (equal 9.6% and 31.0% in average of China), resulting in 1.1 and 2.0 times increases in PM2.5 and PM10 concentrations in populated regions of the Middle Yellow River Basin and the Beijing-Tianjin-Hebei area. The critical threshold friction velocity is the key parameter to judge whether wind-blown dust occurs. Dust flux is sensitive to the bulk soil density (increased by 4.2% and 12.6% for PM2.5 and PM10 after refined soil bulk density) and resolution (increased by 13.5% and 3.5% for PM2.5 and PM10 from 27 km to 9 km). Such results demonstrated the strong correlation between wind speed, frequency, and intensity of dust phenomena from 2013 to 2021. The wind speed can be further enhanced in dust source areas even in the context of a decline in the national average, leading to more frequent and persistent dust storms in March 2050. Only relying on coordinated emission reductions to mitigate climate change, wind-blown dust in northern China still poses considerable potential risks to air quality. Urgent actions should also be taken to improve land-use and land-cover to reduce the area of dust sources.
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Cattin, R., N. Chamot-Rooke, M. Pubellier, A. Rabaute, M. Delescluse, C. Vigny, L. Fleitout e P. Dubernet. "Stress change and effective friction coefficient along the Sumatra-Andaman-Sagaing fault system after the 26 December 2004 (Mw= 9.2) and the 28 March 2005 (Mw= 8.7) earthquakes". Geochemistry, Geophysics, Geosystems 10, n. 3 (marzo 2009): n/a. http://dx.doi.org/10.1029/2008gc002167.
Testo completo
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Kumar, Birendra, Rajen Kumar Nayak e S. N. Singh. "Experimental Analysis of the Thermo-Hydraulic Performance on a Cylindrical Parabolic Concentrating Solar Water Heater with Twisted Tape Inserts in an Absorber Tube". Zeitschrift für Naturforschung A 73, n. 5 (24 maggio 2018): 431–39. http://dx.doi.org/10.1515/zna-2018-0023.
Testo completoAbstract (sommario):
AbstractA twisted tape inserted in an absorber tube may be an excellent option to enhance the performance of a cylindrical parabolic concentrating solar collector (CPC). The present work is an experimental study of the flow and heat transfer with and without twisted tape inserts in the absorber tube of a CPC. Results are presented for mass flow rates of water, ṁ=0.0198–0.0525 kg/s, twist ratio, y=5–10 and Reynolds number, Re=2577.46–6785.55. In the present study, we found that the outlet water temperature, collector efficiency and Nusselt number (Nu) are higher in the twisted tapes as compared to those without the twisted tape inserts in the absorber tube of the CPC. For fixed mass flow rate of water ṁ, the To and η increased with the decrease in twist ratio, y, and is higher in lower twist ratio, y=5, of the twisted tapes. The whole experiment was performed at the Indian Institute of Technology (ISM) in Dhanbad, India during the months of March–April 2017. Based on the experimental data, the correlations for the Nu and friction factor were also developed.
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Carpenter, Chris. "Digital Transformation Enables Automated Real-Time Torque-and-Drag Modeling". Journal of Petroleum Technology 73, n. 01 (1 gennaio 2021): 69–70. http://dx.doi.org/10.2118/0121-0069-jpt.
Testo completoAbstract (sommario):
This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 199670, “Digital Transformation Strategy Enables Automated Real-Time Torque-and-Drag Modeling,” by Dingzhou Cao, Occidental Petroleum; Don Hender, SPE, IPCOS; and Sam Ariabod, Apex Systems, et al., prepared for the 2020 IADC/SPE International Drilling Conference, Galveston, Texas, 3-5 March. The paper has not been peer reviewed. Automated real-time torque-and-drag (RT-T&D) analysis compares real-time measurements with evergreen models to monitor and manage downhole wellbore friction, improving drilling performance and safety. Enabling RT-T&D modeling with contextual well data, rig-state detection, and RT-interval event filters poses significant challenges. The complete paper presents a solution that integrates a physics-based T&D stiff/soft string model with a real-time drilling (RTD) analytics system using a custom-built extract, transform, and load (ETL) translator and digital-transformation applications to automate the T&D modeling work flow. Methodology A T&D representational state transfer (REST) application program interface (API) was integrated with an RTD analytics system capable of receiving and processing both real-time (hookload, torque, and rig-state) and digitized (drillstring and casing components, trajectory profiles, and mud-property) well data across multiple platforms. This strategy consists of four parts: Digital transformation apps, ETL, and translator Physics-based stiff/soft string T&D model API Pre-existing data infrastructure RTD analytics system The data-flow architecture reveals a flexible design in the sense that it can accommodate different types of T&D models or any other physics-based REST API models (e.g., drillstring buckling or drilling hydraulics) and can be accessed offline for prejob/post-job planning. Drilling engineers can also leverage the RTD systems’ historical database to perform recalculations, comparative analysis, and friction calibrations. The RT-T&D model also can be deployed in a cloud environment to ensure that horizontal scalability is achieved.
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Majozi, Nobuhle P., Chris M. Mannaerts, Abel Ramoelo, Renaud Mathieu, Alecia Nickless e Wouter Verhoef. "Analysing surface energy balance closure and partitioning over a semi-arid savanna FLUXNET site in Skukuza, Kruger National Park, South Africa". Hydrology and Earth System Sciences 21, n. 7 (10 luglio 2017): 3401–15. http://dx.doi.org/10.5194/hess-21-3401-2017.
Testo completoAbstract (sommario):
Abstract. Flux towers provide essential terrestrial climate, water, and radiation budget information needed for environmental monitoring and evaluation of climate change impacts on ecosystems and society in general. They are also intended for calibration and validation of satellite-based Earth observation and monitoring efforts, such as assessment of evapotranspiration from land and vegetation surfaces using surface energy balance approaches. In this paper, 15 years of Skukuza eddy covariance data, i.e. from 2000 to 2014, were analysed for surface energy balance closure (EBC) and partitioning. The surface energy balance closure was evaluated using the ordinary least squares regression (OLS) of turbulent energy fluxes (sensible (H) and latent heat (LE)) against available energy (net radiation (Rn) less soil heat (G)), and the energy balance ratio (EBR). Partitioning of the surface energy during the wet and dry seasons was also investigated, as well as how it is affected by atmospheric vapour pressure deficit (VPD), and net radiation. After filtering years with low-quality data (2004–2008), our results show an overall mean EBR of 0.93. Seasonal variations of EBR also showed the wet season with 1.17 and spring (1.02) being closest to unity, with the dry season (0.70) having the highest imbalance. Nocturnal surface energy closure was very low at 0.26, and this was linked to low friction velocity during night-time, with results showing an increase in closure with increase in friction velocity. The energy partition analysis showed that sensible heat flux is the dominant portion of net radiation, especially between March and October, followed by latent heat flux, and lastly the soil heat flux, and during the wet season where latent heat flux dominated sensible heat flux. An increase in net radiation was characterized by an increase in both LE and H, with LE showing a higher rate of increase than H in the wet season, and the reverse happening during the dry season. An increase in VPD is correlated with a decrease in LE and increase in H during the wet season, and an increase in both fluxes during the dry season.
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Dong, X., J. S. Fu, K. Huang e D. Tong. "Model development of dust emission and heterogeneous chemistry within the Community Multiscale Air Quality modeling system and its application over East Asia". Atmospheric Chemistry and Physics Discussions 15, n. 24 (17 dicembre 2015): 35591–643. http://dx.doi.org/10.5194/acpd-15-35591-2015.
Testo completoAbstract (sommario):
Abstract. The Community Multiscale Air Quality (CMAQ) model has been further developed in terms of simulating natural wind-blown dust in this study, with a series of modifications aimed at improving the model's capability to predict the emission, transport, and chemical reactions of dust aerosols. The default parameterization of threshold friction velocity constants in the CMAQ are revised to avoid double counting of the impact of soil moisture based on the re-analysis of field experiment data; source-dependent speciation profiles for dust emission are derived based on local measurements for the Gobi and Taklamakan deserts in East Asia; and dust heterogeneous chemistry is implemented to simulate the reactions involving dust aerosol. The improved dust module in the CMAQ was applied over East Asia for March and April from 2006 to 2010. Evaluation against observations has demonstrated that simulation bias of PM10 and aerosol optical depth (AOD) is reduced from −55.42 and −31.97 % in the original CMAQ to −16.05 and −22.1 % in the revised CMAQ, respectively. Comparison with observations at the nearby Gobi stations of Duolun and Yulin indicates that applying a source-dependent profile helps reduce simulation bias for trace metals. Implementing heterogeneous chemistry is also found to result in better agreement with observations for sulfur dioxide (SO2), sulfate (SO42-), nitric acid (HNO3), nitrous oxides (NOx), and nitrate (NO3-). Investigation of a severe dust storm episode from 19 to 21 March 2010 suggests that the revised CMAQ is capable of capturing the spatial distribution and temporal variations of dust aerosols. Model evaluation indicates potential uncertainties within the excessive soil moisture fraction used by meteorological simulation. The mass contribution of fine mode aerosol in dust emission may be underestimated by 50 %. The revised revised CMAQ provides a useful tool for future studies to investigate the emission, transport, and impact of wind-blown dust over East Asia and elsewhere.