Academic literature on the topic 'Calibrable facets'
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Journal articles on the topic "Calibrable facets"
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Watson, Victoria Theresa, and Andrew Scott Medeiros. "The value of paleolimnology in reconstructing and managing ecosystem vulnerability: a systematic map." FACETS 6, no. 1 (January 1, 2021): 517–36. http://dx.doi.org/10.1139/facets-2020-0067.
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Vulnerability can measure an ecosystem’s susceptibility to change as a result of pressure or disturbance, but can be difficult to quantify. Reconstructions of past climate using paleolimnological methods can create a baseline to calibrate future projections of vulnerability, which can improve ecosystem management and conservation plans. Here, we conduct a systematic map to analyze the range and extent that paleolimnological published studies incorporated the concept of vulnerability. Additional themes of monitoring, management, conservation, restoration, or ecological integrity were also included. A total of 52 relevant unique articles were found, a majority of which were conducted in Europe or North America since 2011. Common themes identified included management and adaptation, with the latter heavily focussed on climate change or disturbance. From this, we can infer that the use of paleolimnology to discuss the concept of vulnerability is an emerging field. We argue that paleolimnology plays a valid role in the reconstruction of ecosystem vulnerability due to its capacity to broaden the scope of long-term monitoring, as well as its potential to help establish management and restoration plans. The use of paleolimnology in vulnerability analysis will provide a clearer lens of changes over time; therefore, it should be frequently implemented as a tool for vulnerability assessment.
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Coibion, Olivier, and Yuriy Gorodnichenko. "Information Rigidity and the Expectations Formation Process: A Simple Framework and New Facts." American Economic Review 105, no. 8 (August 1, 2015): 2644–78. http://dx.doi.org/10.1257/aer.20110306.
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We propose a new approach to test the full-information rational expectations hypothesis which can identify whether rejections of the null arise from information rigidities. This approach quantifies the economic significance of departures from the null and the underlying degree of information rigidity. Applying this approach to US and international data of professional forecasters and other agents yields pervasive evidence consistent with the presence of information rigidities. These results therefore provide a set of stylized facts which can be used to calibrate imperfect information models. Finally, we document evidence of state-dependence in the expectations formation process. (JEL C53, D83, D84, E13, E31, E37)
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Weigelt, Oliver, J. Charlotte Seidel, Lucy Erber, Johannes Wendsche, Yasemin Z. Varol, Gerald M. Weiher, Petra Gierer, Claudia Sciannimanica, Richard Janzen, and Christine J. Syrek. "Too Committed to Switch Off—Capturing and Organizing the Full Range of Work-Related Rumination from Detachment to Overcommitment." International Journal of Environmental Research and Public Health 20, no. 4 (February 17, 2023): 3573. http://dx.doi.org/10.3390/ijerph20043573.
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Work-related thoughts during off-job time have been studied extensively in occupational health psychology and related fields. We provide a focused review of the research on overcommitment—a component within the effort–reward imbalance model—and aim to connect this line of research to the most commonly studied aspects of work-related rumination. Drawing on this integrative review, we analyze survey data on ten facets of work-related rumination, namely (1) overcommitment, (2) psychological detachment, (3) affective rumination, (4) problem-solving pondering, (5) positive work reflection, (6) negative work reflection, (7) distraction, (8) cognitive irritation, (9) emotional irritation, and (10) inability to recover. First, we apply exploratory factor analysis to self-reported survey data from 357 employees to calibrate overcommitment items and to position overcommitment within the nomological net of work-related rumination constructs. Second, we leverage apply confirmatory factor analysis to self-reported survey data from 388 employees to provide a more specific test of uniqueness vs. overlap among these constructs. Third, we apply relative weight analysis to assess the unique criterion-related validity of each work-related rumination facet regarding (1) physical fatigue, (2) cognitive fatigue, (3) emotional fatigue, (4) burnout, (5) psychosomatic complaints, and (6) satisfaction with life. Our results suggest that several measures of work-related rumination (e.g., overcommitment and cognitive irritation) can be used interchangeably. Emotional irritation and affective rumination emerge as the strongest unique predictors of fatigue, burnout, psychosomatic complaints, and satisfaction with life. Our study is intended to assist researchers in making informed decisions on selecting scales for their research and paves the way for integrating research on the effort–reward imbalance and work-related rumination.
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Hsieh, Tsung-Han, Ming-Xian Lin, Kuan-Ting Yeh, and Tsukasa Watanabe. "Calibration of a Rotary Encoder and a Polygon Using a Two-Autocollimator Method." Applied Sciences 13, no. 3 (January 31, 2023): 1865. http://dx.doi.org/10.3390/app13031865.
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In this work, we propose a two-autocollimator method in which all pitch angle deviations of a polygon and angle errors of a rotary encoder can be calibrated simultaneously. A polygon with any number of faces can be calibrated. Any face of the polygon has is a measurement cycle of one. Compared to a traditional method, cross-calibration calibrates a rotary encoder and a polygon. This method can simultaneously calibrate all pitch angle deviations of the polygon and angle errors of the rotary encoder. The measurement cycle depends on how many faces the polygon has. There are 24 measurement cycles for a 24-faced polygon. In the experiment, we use two autocollimators to calibrate a 24-faced polygon and the SelfA rotary encoder to conduct the proposed two-autocollimator method. According to the uncertainty evaluation, the expanded uncertainty is 0.46”. For a 95% confidence level, the coverage factor is 2.00. To verify all pitch angle deviations, the shift-angle method, based on cross-calibration, uses one autocollimator to measure the same polygon. The difference in pitch angle deviations is smaller than ± 0.28”. The maximum En-value is 0.58. The SelfA rotary encoder comprises 12 read heads and calibrates using self-calibration. The difference in angle errors is smaller than ± 0.27”. The maximum En-value is 0.59. The two En-values mean that the proposed two-autocollimator method is practical.
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Tseng, Wen-Ta, Tzi-Ying Su, and John-Michael L. Nix. "Validating Translation Test Items via the Many-Facet Rasch Model." Psychological Reports 122, no. 2 (April 11, 2018): 748–72. http://dx.doi.org/10.1177/0033294118768664.
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This study applied the many-facet Rasch model to assess learners’ translation ability in an English as a foreign language context. Few attempts have been made in extant research to detect and calibrate rater severity in the domain of translation testing. To fill the research gap, this study documented the process of validating a test of Chinese-to-English sentence translation and modeled raters’ scoring propensity defined by harshness or leniency, expert/novice effects on severity, and concomitant effects on item difficulty. Two hundred twenty-five, third-year senior high school Taiwanese students and six educators from tertiary and secondary educational institutions served as participants. The students’ mean age was 17.80 years ( SD = 1.20, range 17–19). The exam consisted of 10 translation items adapted from two entrance exam tests. The results showed that this subjectively scored performance assessment exhibited robust unidimensionality, thus reliably measuring translation ability free from unmodeled disturbances. Furthermore, discrepancies in ratings between novice and expert raters were also identified and modeled by the many-facet Rasch model. The implications for applying the many-facet Rasch model in translation tests at the tertiary level were discussed.
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Oliva, A., S. Akamatsu, and P. G. Schyns. "Chromatic Cues for Face Detection in Natural Scenes." Perception 26, no. 1_suppl (August 1997): 294. http://dx.doi.org/10.1068/v970316.
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One of the challenging problems of human and machine vision is the detection of objects against complex backgrounds. Our research addresses the question of how faces can be very quickly detected in naturalistic scenes on the basis of luminance and chromatic cues. Although luminance information varies with pose and illumination differences, chromatic information is by and large invariant under these transformations. Hence, chromatic information might be a very powerful cue for segmentation and detection. We compared faces of different pigmentation against background scenes of different colours. Specifically, colour histograms were computed in a perceptually uniform colour space (L*u*v*). We computed the Euclidian distances between the averages of the colour histograms of faces and scenes in L*u*v*. This metric was used to calibrate the contrast between face and scene colour in the experimental design. In a face detection task, subjects saw faces against scene backgrounds at a different distance in colour space. Each combination face - scene was presented for 120 ms (to prevent saccadic explorations), and the subject's task was to indicate whether or not a face was present. Controls involved face - scene pairs on an isoluminant background. Results revealed that luminance information did not affect detection on the basis of chromatic cues. Importantly, the metric of detectability in L*u*v* space between scene and faces predicted reaction times to detection.
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Alshaibani, Abdullah, Sylvia Carrell, Li-Hsin Tseng, Jungmin Shin, and Alexander Quinn. "Privacy-Preserving Face Redaction Using Crowdsourcing." Proceedings of the AAAI Conference on Human Computation and Crowdsourcing 8 (October 1, 2020): 13–22. http://dx.doi.org/10.1609/hcomp.v8i1.7459.
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Redaction of private information from images is the kind of tedious, yet context-independent, task for which crowdsourcing is especially well suited. Despite tremendous progress, machine learning is not keeping pace with the needs of sensitive applications in which inadvertent disclosure could have real-world consequences. Human workers can detect faces that machines cannot; however, an open call to crowds would entail disclosure. We present IntoFocus, a method for engaging crowd workers to redact faces from images without disclosing the facial identities of people depicted. The method works iteratively, starting with a heavily filtered form of the image, and gradually reducing the strength of the filter, with a different set of workers reviewing the image at each step. IntoFocus exploits the gap between the filter level at which a face becomes unidentifiable and the level at which it becomes undetectable. To calibrate the algorithm, we performed a perceptual study of detection and identification of faces in images filtered with the median filter. We present the system design, the results of the perception study, and the results of a summative evaluation of the system
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Sun, W., R. R. Baize, C. Lukashin, and Y. Hu. "Deriving polarization properties of desert-reflected solar spectra with PARASOL data." Atmospheric Chemistry and Physics 15, no. 13 (July 15, 2015): 7725–34. http://dx.doi.org/10.5194/acp-15-7725-2015.
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Abstract. One of the major objectives of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) is to conduct highly accurate spectral observations to provide an on-orbit inter-calibration standard for relevant Earth-observing sensors with various channels. To calibrate an Earth-observing sensor's measurements with the highly accurate data from the CLARREO, errors in the measurements caused by the sensor's sensitivity to the polarization state of light must be corrected. For correction of the measurement errors due to the light's polarization, both the instrument's dependence on the incident polarization state and the on-orbit knowledge of the polarization state of light as a function of observed scene type, viewing geometry, and solar wavelength are required. In this study, an algorithm for deriving the spectral polarization state of solar light from the desert is reported. The desert/bare land surface is assumed to be composed of two types of areas: fine sand grains with diffuse reflection (Lambertian non-polarizer) and quartz-rich sand particles with facets of various orientations (specular-reflection polarizer). The Adding–Doubling Radiative Transfer Model (ADRTM) is applied to integrate the atmospheric absorption and scattering in the system. Empirical models are adopted in obtaining the diffuse spectral reflectance of sands and the optical depth of the dust aerosols over the desert. The ratio of non-polarizer area to polarizer area and the angular distribution of the facet orientations are determined by fitting the modeled polarization states of light to the measurements at three polarized channels (490, 670, and 865 nm) by the Polarization and Anisotropy of Reflectances for Atmospheric Science instrument coupled with Observations from a Lidar (PARASOL). Based on this physical model of the surface, the desert-reflected solar light's polarization state at any wavelength in the whole solar spectra can be calculated with the ADRTM.
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Bonnefoy, Léa E., Jean-François Lestrade, Emmanuel Lellouch, Alice Le Gall, Cédric Leyrat, Nicolas Ponthieu, and Bilal Ladjelate. "Probing the subsurface of the two faces of Iapetus." EPJ Web of Conferences 228 (2020): 00006. http://dx.doi.org/10.1051/epjconf/202022800006.
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Saturn’s moon Iapetus, which is in synchronous rotation, is covered by an optically dark material mainly on its leading side, while its trailing side is significantly brighter. Because longer wavelengths probe deeper into the subsurface, observing both sides at a variety of wavelengths brings to light possible changes in thermal, compositional, and physical properties with depth. We have observed Iapetus’s leading and trailing hemispheres at 1.2 and 2.0 mm, using the NIKA2 camera mounted on the IRAM 30-m telescope, and compared our observations to others performed at mm to cm wavelengths. We calibrate our observations on Titan, which is simultaneously observed within the field of view. Due to the proximity of Saturn, it is sometimes difficult to separate Iapetus’s and Titan’s flux from that of Saturn, detected in the telescope’s side lobes. Preliminary results show that the trailing hemisphere brightness temperatures at the two wavelengths are equal within error bars, unlike the prediction made by Ries (2012)[1]. On the leading side, we report a steep spectral slope of increasing brightness temperature (by 10 K) from 1.2 to 2.0 mm, which may indicate rapidly varying emissivities within the top few centimeters of the surface. Comparison to a diffuse scattering model and a thermal model will be necessary to further constrain the thermophysical properties of the subsurface of Iapetus’s two faces.
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Faberman, R. Jason, Andreas I. Mueller, Aysegül Sahin, and Giorgio Topa. "Job Search Behavior Among the Employed and Non‐Employed." Econometrica 90, no. 4 (2022): 1743–79. http://dx.doi.org/10.3982/ecta18582.
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We develop a unique survey that focuses on the job search behavior of individuals regardless of their labor force status and field it annually starting in 2013. We use our survey to study the relationship between search effort and outcomes for the employed and non‐employed. Three important facts stand out: (1) on‐the‐job search is pervasive, and is more intense at the lower rungs of the job ladder; (2) the employed are at least three times more effective than the unemployed in job search; and (3) the employed receive better job offers than the unemployed. We set up a general equilibrium model of on‐the‐job search with endogenous search effort, calibrate it to fit our new facts, and find that the search effort of the employed is highly elastic. We show that search effort substantially amplifies labor market responses to productivity shocks over the business cycle.
Dissertations / Theses on the topic "Calibrable facets"
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Amato, Stefano. "Some results on anisotropic mean curvature and other phase transition models." Doctoral thesis, SISSA, 2015. http://hdl.handle.net/20.500.11767/4859.
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The present thesis is divided into three parts. In the first part, we analyze a
suitable regularization — which we call nonlinear multidomain model — of the
motion of a hypersurface under smooth anisotropic mean curvature flow. The
second part of the thesis deals with crystalline mean curvature of facets of a
solid set of R^3 . Finally, in the third part we study a phase-transition model for
Plateau’s type problems based on the theory of coverings and of BV functions.
Book chapters on the topic "Calibrable facets"
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Lee, Jack T., and Rajani Naidoo. "Complicit Reproductions in the Global South: Courting World Class Universities and Global Rankings." In Evaluating Education: Normative Systems and Institutional Practices, 77–91. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7598-3_6.
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AbstractThe proliferation of global rankings has led to vigorous debates about the dominance of world-class universities and the encroaching institutional isomorphism in higher education. Specifically, the narrow metrics of rankings celebrate STEM research and institutional reputation at the expense of the humanist roots of higher education: teaching, self-cultivation, and community engagement. This critique on global rankings faces an equally vocal demand that a country must develop world-class universities in order to remain economically competitive in the global era – an instrumental logic that attracts devotees in both advanced economies as well as developing economies. Ironically, policymakers in both contexts simultaneously lament the prevalence of rankings and calibrate strategies to promote success in league tables. Although rankings attract scrutiny in both higher education policymaking and research, the implications of these metrics on higher education in the Global South receive little attention. The discourse is largely focused on top and mid ranking institutions, which are often located in the Global North. In the Global South, global rankings and the concept of world-class universities act through subtle yet powerful mechanisms to shape the contours of higher education. For many institutions and states in the Global South, the fervour is less about creating a world-class university and more about establishing links with well ranked universities (domestically and internationally). Therefore, while the explicit goal is not to build a world-class university, policymakers are nevertheless complicit in reproducing the hegemony of global rankings. This chapter will examine the activities in which global rankings exert tremendous pressure on the Global South: curriculum development, student mobility, faculty recruitment, research partnerships, and strategic planning. In mapping out the mechanisms of reproduction, the goal is to highlight the pervasive influence of global rankings and the complicity in reproduction rather than paint a binary division between the global and local dimensions of higher education.
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Bavelas, Janet Beavin. "Meaning and Understanding as an Interactional Process." In Face-to-Face Dialogue, 145–62. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780190913366.003.0009.
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Individualistic theories locate meaning in a word, a context, or a speaker’s intention. Several authors have criticized these as an implicit conduit metaphor, in which meaning is packaged in language and passed from one person to another. Others have described meaning instead as an interactive process but have provided few specifics about this process. Our research team started with G. H. Mead’s triadic model and proposed a second-by-second process of three steps with which a speaker and addressee assure mutual understanding: (a) The speaker presents information new to the dialogue; (b) their addressee responds with an implicit or explicit display of understanding; and (c) the speaker acknowledges this response as sufficient evidence of understanding. With each successive triad, speaker and addressee calibrate each other’s understanding. We operationalized and tested this model on a random sample of getting-acquainted conversations and confirmed continuous three-step sequences, about every 5 seconds, throughout the dialogues.
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Bavelas, Janet Beavin. "A Summary So Far." In Face-to-Face Dialogue, 197–200. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780190913366.003.0012.
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The research in this book arose from curiosity about the workings of face-to-face dialogue, which is the basic form of language use. Our research team has applied microanalysis of face-to-face dialogue to interaction rather than individuals and to co-speech gestures rather than nonverbal communication. The research section began with an intensive study of how narrators and addressees influence each other during story-telling. Then it traced the discovery of an unsuspected effect of dialogue, which (unlike monologue) favors analogic or iconic forms such as hand and facial gestures, figurative language, and direct quotations. Numerous studies showed essential contributions of hand and facial co-speech gestures to both the topic and the process of having a dialogue. Finally, we documented a three-step, moment-by-moment process with which interlocutors calibrate their mutual understanding. The final chapters described studies that applied our microanalysis method to computer-medicated communication, infant autism, and medical and psychotherapeutic dialogues.
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Saria, Vaibhav. "In False Brothers, Evil Awakens." In Hijras, Lovers, Brothers, 62–99. Fordham University Press, 2021. http://dx.doi.org/10.5422/fordham/9780823294701.003.0003.
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This chapter studies the relationship that hijras have with various members of their family, focusing on the fraternal bond as it occupies the Archimedean point or pivot that reveals how hijras calibrate their relationship with the various members of their family in light of the fact they used to be men, but are not anymore. The presence of a hijra within the family, gauged through such things as the anxiety of property transmission and inheritance, calls for reconfiguring the accepted notions of kinship, care, and asceticism that often define anthropological investigations of sexuality.
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Lounsberry, Barbara. "Warnings." In Virginia Woolf, the War Without, the War Within, 101–37. University Press of Florida, 2018. http://dx.doi.org/10.5744/florida/9780813056937.003.0004.
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“By the summer of 1934,” Hermione Lee writes, Hitler's “ambitions and his methods were fully apparent.” In the mid-1930s, Nazis issue regulations to eliminate women doctors and lawyers in Germany. German universities reduce the female quota of students to just ten percent. On October 28, 1934, Oswald Mosley stages a vicious attack on Jews during a British Union of Fascists rally at the Royal Albert Hall. Beyond these alarming national and international threats, Woolf faces inner personal (and artistic) loss and outer public attack, as she writes in her diary. She starts to speak of “warnings” in this journal. However, André Gide’s Pages de Journal, 1929–32 give her new direction in August 1934. In September, Guy de Maupassant's travel diary Sur l’eau (Afloat) particularly helps her to navigate through Roger Fry's unexpected death. She both enters its words in her diary and uses Afloat for a key moment in her novel The Years. In October, Alice James's Journal helps Woolf calibrate British women's social and sexual lives in the first decades of The Years and shows her—as do Gide's and Maupassant's diaries—a fierce fight, both without and within, between constraint and freedom.
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Blais, Jean-Guy, Bernard Charlin, Julie Grondin, Carole Lambert, Nathalie Loye, and Robert Gagnon. "Estimation du degré d’accord entre des experts lors du calibrage d’un test de concordance de script avec le modèle à facettes de Rasch." In Des mécanismes pour assurer la validité de l'interprétation de la mesure en éducation, 139–62. Presses de l'Université du Québec, 2011. http://dx.doi.org/10.2307/j.ctv18phchp.10.
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O'Donoghue, Cathal. "Labour-Supply Behaviour." In Practical Microsimulation Modelling, 115–49. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198852872.003.0005.
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In the preceding chapters, the focus was on simulating policies that aim to reduce poverty, generate revenue, or redistribute resources. However, many public policies also try to incentivize behaviour, such as those to improve labour participation or supply, or to change behaviours in relation to savings or pollution. Social- and fiscal-policy instruments face a fundamental trade-off. An instrument that performs well from an income-maintenance perspective may have unintended behavioural consequences. This chapter considers the structure of instruments that have an explicit goal to improve behavioural response, particularly focusing on in-work benefits. The chapter also describes how to use a microsimulation mode to simulate the inputs required for the estimation of a behavioural-econometric model, and then estimates a revealed-preference-choice model. The chapter then describes a method often used in microsimulation models to calibrate choice models for simulation purposes. In terms of measurement issues related to the behavioural analysis, we describe the design and use of replacement rates. The chapter concludes by undertaking a simulation of the introduction of a change in in-work benefits.
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Mespoulet, Jérôme, and Pierre Louis Hereil. "An Overview of Theoretical and Experimental Techniques for Material Behavior Characterization in Shock Physics." In Critical Energy Infrastructure Protection. IOS Press, 2022. http://dx.doi.org/10.3233/nicsp220005.
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Shock Physics that deals with material behavior at a very high strain rate (in the order of material propagation speed) reveals more and more its importance in engineering applications (automotive, defense, aeronautic, space, energy, etc.), geophysics (earth’s behavior, asteroid impacts) or astrophysics (planets and stars behavior). Nowadays, this term is used more often when classical high-speed dynamics reach their physical limits. After a short introduction to shock physics, an application to lightweight armor is used to illustrate the importance of coupling tuned experiments with simulations for dynamic material studies: In fact, lightweight armors of soldiers are in constant evolution to optimize protection efficiency. In this area, more and more complex simulations are investigated with compound structures including polymeric foam, composite, metal, and ceramic. Even if numerical capabilities are in perpetual evolution, there is a constant need of improving the knowledge of individual material response in the strain, strain rate regime closed to the threat. Collecting parameters for Equation Of State (EOS), strength and/or rupture models to fit material models is thus mandatory to ensure reliable numerical investigations. Since 2015, THIOT INGENIERIE Shock Physics Laboratory has been selected by the French Ministry Of Defense (MOD) Land Systems to perform materials characterization in three main families of ballistic materials. Parallel to those tasks, in-house simulations done by the dynamic material department have shown a very good agreement with validation tests based on the dynamic material characterizations. A coupled approach between laboratory experiments and numerical simulations has shown its relevance with ceramic, [1], an Ultra High Molecular Weight Polyethylene composite (UHMWPE) [2] and a polymeric foam [3]. For all those materials, the BBA methodology has been used to calibrate EOS, strength, and damage models by conducting a step-by-step procedure with a dual approach, mixing together experimental tests and numerical works simultaneously.
Conference papers on the topic "Calibrable facets"
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Glaser, Carrie, Joel Mazza, and John Frame. "Empowering Completion Engineers to Calibrate Petrophysical Facies Models to Hydraulic Fracturing Treatment Responses." In Unconventional Resources Technology Conference. Tulsa, OK, USA: American Association of Petroleum Geologists, 2019. http://dx.doi.org/10.15530/urtec-2019-1001.
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Conkol, Gary K. "Climate Change and Global Warming - The Forgotten Factors." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-70096.
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Abstract The recent global pandemic has provided an unparalleled opportunity to examine and potentially calibrate our responses to Global Warming. Since 1992 there has been much debate but also vast deployment of technology from satellites to atmospheric monitoring stations to study climate change and, specifically, global warming. Copious amounts of atmospheric temperature and Greenhouse Gas (GHG) data have been continuously recorded. Data throughout the 2019 pandemic to present, now provide the rare opportunity to test understanding of Global Warming and resulting Climate Change. Herein, changes in temperature and Green House Gases with respect to the time, during which global activities shut down or were significantly decreased, are used to design a multi-faceted approach to further examine our understanding and actions relative to Global Warming. A combination of perturbation and sensitivity analysis are proposed to draw attention to short and long-term efforts that have the potential to help further understand and calibrate efforts to manage Global Warming. The primary focus is to utilize changes noted during the pandemic to inform calculations and global warming predictions and actions.
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Bardetsky, Alexander, Helmi Attia, and Mohamed Elbestawi. "A Fracture Mechanics Approach to the Prediction of Tool Wear in Dry High Speed Machining of Aluminum Cast Alloys: Part 2 — Model Calibration and Verification." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80640.
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Experimental study has been carried out to establish the effect of cutting conditions (speed, feed, and depth of cut) on the cutting forces and time variation of carbide tool wear data in high-speed machining (face milling) of Al-Si cast alloys that are commonly used in the automotive industry. The experimental setup and force measurement system are described. The test results are used to calibrate and validate the fracture mechanics-based tool wear model developed in Part 1 of this work. The model calibration is conducted for two combinations of cutting speed and a feed rate, which represent a lower and upper limit of the range of cutting conditions. The calibrated model is then validated for a wide range of cutting conditions. This validation is performed by comparing the experimental tool wear data with the tool wear predicted by calibrated cutting tool wear model. The prediction errors were found to be less then 7%, demonstrating the accuracy of the object oriented finite element (OOFE) modeling of the crack propagation process in the cobalt binder. It also demonstrates its capability in capturing the physics of the wear process. This is attributed to the fact that the OOF model incorporates the real microstructure of the tool material.
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Meskell, Craig. "On the Underlying Fluid Mechanics Responsible for Damping Controlled Fluidelastic Instability in Tube Arrays." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71468.
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Granger and Paidoussis hypothesized that damping controlled fluidelastic instability is in fact due to the generation and convection of vorticity. In this paper a simple wake model consisting of a convecting vortex sheet is proposed to represent the transient nature of fluidelastic forces present in a tube array. Using this model, the memory function proposed by Granger and Paidoussis has been obtained by numerical integration without the need to calibrate the model with experimental data. The resulting function is found to compare well with the first and second order approximations which were determined empirically. However, the current model does not exhibit the physically unrealistic features of the approximations. Furthermore, the memory function has been combined with experimental data for the static fluid force to produce a prediction of the critical velocity for a range of mass damping parameter. This stability threshold is in reasonable agreement with experimental data. Therefore it is concluded that vorticity transport is in fact the mechanism responsible for damping controlled fluidelastic instability.
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Yao, Jiang, Prabhav Saraswat, Manoj Chinnakonda, Juan A. Hurtado, Victor Oancea, and Subham Sett. "A Computationally Efficient and Accurate Lumbar Spine Model." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14473.
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The design of spine implants requires a good understanding of spine kinematics and loading conditions. Realistic simulation of each functional spinal unit (FSU) requires capturing complicated contact and deformation of biological tissues in a computationally efficient manner. Specifically, the complexities include contacts in intervertebral and facet joints, restraints of spine ligaments, as well as realistic material properties of soft tissues. The variation in the stiffness among different FSUs is often neglected in spine modeling, which might be crucial for spine function. A hybrid approach for lumbar spine modeling was established that combined motion capture experiments, kinematic spine modeling and detailed finite element modeling. Motion capture data during flexion was collected and used to drive the spine model. For computational efficiency each FSU was modeled as an intervertebral connector (joint) element with different elastic behavior at each level. The connector behavior was calibrated using experimental data on the whole lumbar spinal motion (Wong et al. 2006) and cadaveric moment-rotation relationship of L45 (Heurer et al. 2007). Then the predicted stiffness for L23 was used to calibrate the material properties of a detailed FEM of L23.
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Bouzida, Yasmina, Eduardo Adrian Cazeneuve, Angelos Mavromatidis, Khalfan Al Ali, and Thomas Leythaeuser. "Reservoir Characterization, Bridging the Scale from Micro to Macro." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211693-ms.
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Abstract This paper describes the reservoir characterization of a carbonate formation using acoustic and borehole imaging log in a novel way. Interpretation of the interplay between stratigraphic and structural reservoir elements allows additional understanding of the hydrocarbon trapping mechanism and informs decisions on the well testing program and future well placement. High-resolution Borehole Images (BHI) have historically been one of the most widespread geological evaluation tools and they continue to be a cornerstone for providing precise data on the facies and fractures intersected by the well. The shallow depth of investigation of wellbore imaging tools can now also be usefully augmented by the acoustic, Dipole shear processing. Patented Deep Shear Wave Image (DSWI) methodology allows identification of geological interfaces with a depth of investigation up to 110 feet away from the borehole. The processed data bridges the gap between wellbore images and field scale seismic data and so can guide meaningful reservoir descriptions and fracture characterization at the geo-cellular mode scale. Combination of the two separate imaging measurements compensates for the limitation of each logging tool's capabilities and helps increase the range of feature detection from near borehole to as much as 110 or more feet away from the well. The statistically rich borehole imaging data can be used to help confirm the detailed characteristic of these features and how the facies/lithology affect the fracture properties. BHI also calibrate the DSWI features true azimuth, while the DSWI data can help confirm fracture hierarchies and fracture bed interaction away from the borehole. The current study highlighted that the different scales of measurement allow additional quantified analysis of the fracture hierarchy and leads to proposal of conceptual fracture models that recognize bed-bound and non-bed-bound fractures sets. The reservoir itself is highly stratified with intercalations of limestone, mudstone and evaporite. Hydrocarbon (HC) presence, defined by an acoustic derived HC Index (but validated with conventional resistivity logging), suggests that oil is preferentially trapped in successive porous layers, but enhanced in some intervals by the additional presence of fractures. The Reservoir pressure points have indicated that only main faults-oriented NNW-SSE could potentially compartmentalized the reservoir. Additional wells and data integration are needed to confirm it. The DSWI is also useful to calibrate the poor to moderate seismic data in this field by detecting sub-seismic features that have an impact on the reservoir and helps in updating the geological and reservoir model.
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Mabrouk, Ibrahim. "Integrating XRD and Well Logging Data to Establish Electro-Facies and Permeability Models for an Unconventional Heterogeneous Tight Gas Reservoir, Obaiyed Giant Gas Field." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/208626-stu.
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Abstract Formation evaluation in heterogeneous reservoirs can be very challenging especially in fields that extend over several kilometers in area where the permeability varies from 0.1 mD up to 1000 D within the same porosity. The porosity, hydrocarbon saturation and net sand thickness in most of Obaiyed field wells are consistent; hence, the productivity of these wells is enormously dependent on the reservoir permeability. Since the permeability is highly heterogeneous, initial production rate of the wells varies between few MMSCFD to almost one hundred MMSCFD. The huge permeability variation led to a tremendous uncertainty in the dynamic modeling, which resulted in an inaccurate production forecast affecting the field economics estimation. Understanding permeability distribution and heterogeneity in Obaiyed field is the key factor for establishing a realistic permeability model, which will lead to a successful field development strategy. Extensive work was performed to understand key factors that govern the permeability in Obaiyed using the data of 1-kilometer length of cores acquired in more than 50 wells covering different reservoir properties in the field. Core data were used to separate the reservoir into different Hydraulic Flow Units (HFU) according to Amaefule's work performed on the Kozeny-Carmen model. Afterwards, a correlation between the HFU and well logs was established using IPSOM Electro-Facies module in order to define the flow units in un-cored wells. The result of this correlation was used to calibrate a Porosity-Permeability relationship for each flow unit. The next step was examining the clay-type distribution and diagenesis in each flow unit using the petrographic analysis (XRD) results from the core xdata. All factors controlling the permeability can now be represented in hydraulic flow units which are considered as a method of measurement of the reservoir quality. Consequently, property maps were constructed showing the location and continuity of each of the flow units, leading to a more deterministic approach in the well placement process. Based on this new work methodology, a production cut-off criteria relating the reservoir productivity to both clay minerals presence and percentages was established for multiple wells scenarios. As a result, the development strategy of the field changed from only vertical wells to include horizontal wells as well which proved to be the only economic approach to produce the Illite dominated zones. This paper presents a workflow to provide a representative estimation of permeability in extremely heterogeneous reservoirs especially the ones dominated by complex clay distribution.
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George, Derosh, Marc Madou, and Edwin A. Peraza Hernandez. "Characterization and Design of Programmable Self-Folding Polymer Films." In ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/smasis2020-2286.
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Abstract This paper presents the characterization and design aspects of a novel fabrication method that integrates photolithography and self-folding to create polymer polyhedral structures. A two-step UV exposure process is used to produce patterned polymer films with flexible folds of low cross-linking density and stiff faces of high cross-linking density. Solvent is diffused into the folds during the development step of the photolithography process due to their low cross-linking density. The solvent concentration is non-uniform across the thickness of the folds and causes a strain gradient at these regions when the solvent is removed by heating the films, which enables self-folding. Experiments are performed to calibrate an equation that relates the dimensions of the folds and their achieved fold angle. An analytical model is introduced to elucidate the form of the equation and provide physical meaning to the calibration parameter. The formula is incorporated into a computational implementation of the unfolding polyhedra method that considers smoothly bent folds. This method, enhanced with the experimentally calibrated formula, enables the design of planar films programmed to self-fold into target three-dimensional shapes when heated. Polyhedral shapes are fabricated to demonstrate the developed method for origami-based fabrication. A parametric study quantifying the accuracy of the designed polyhedral forms with smooth folds as compared against those with idealized creased folds is performed.
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Adel Gabry, Mohamed, Ibrahim Eltaleb, M. Y. Soliman, S. M. Farouq-Ali, Paul J. Cook, Florian A. Soom, and Yves Guglielmi. "Validation of Continuous Wavelet Transform Closure Detection Technique Using Strain Measurements." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212360-ms.
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Abstract Although closure detection has a crucial role in hydraulic fracturing operations, significant debate surrounds the various methodologies to determine its value. Several competing methodologies have been presented in the literature that sometimesyield significantly different estimates of closure pressure and time. The conventional techniques rely on assumptions that may be competing or even contradictory. The continuous wavelets transform technique is a data transform technique that convolves the pressure and/or temperature data using a short wavy signal called "wavelet". The wavelet transform provides a representation of the pressure signal by letting the translation and scale parameters of the wavelets vary continuously. That enables the analyst to find the details of the pressure data by observing the wavelet energy spectrum for the monitored signal (pressure and/or temperature) signal. In this case the event of contact between two fracture faces and complete fracture closure is clearly identified. As a part of The EGS Collab project, a series of fracture injection tests have been conducted to estimate the minimum principal stress with direct observation of well bore deformation using the SIMFIP tool (Step-Rate Injection Method for Fracture In-Situ Properties). The tool monitors the deformation using strain gauges as a fracture opens and closes during multiple tests. The publicly available data provide a great opportunity to experimentally calibrate the new technique for detecting the closure event using continuous wavelet transform. The effect of fracture closure events and fracture faces contact events detected using continuous wavelet transform were compared to the experimental measured deformation. The continuous wavelet transform technique for closure detection showed an agreement with the deformation measurement. The effect of the presence of natural fractures and complex fracture closure events were recognized using the continuous wavelet transform technique. The Contineous Wavelet Transform (CWT) is a global technique that can be applied to the pressure decline data without requiring further information about the reservoir geomechanical parameters or pumping data. The technique can be easily embedded in machine learning algorithms for hydraulic fracturing diagnostics.
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Rice, M. C., C. A. Fleischer, D. D. R. Cartie, and Marc Zupan. "Light Weight Sandwich Panels for Yacht Hull Structures." In SNAME 17th Chesapeake Sailing Yacht Symposium. SNAME, 2005. http://dx.doi.org/10.5957/csys-2005-016.
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Improving lightweight structures is a continuous challenge for yacht hull structural components. Sandwich beams consisting of strong face sheets and a low density core have gained application as weight efficient structures subjected to bending loads. The sandwich structure provides good stiffness by keeping the face sheets at a fixed distance with considerable weight reduction over a statically equivalent monolithic panel. New fabrication technologies now allow for hybrid sandwich structures, known as X-cor to be manufactured. X-cor panels consist of carbon fiber face sheets separated by a closed cell polymer foam core reinforced with carbon fiber or metallic (Titanium or Steel) pins. The pins are inserted into the light weight foam core in the out-of-plane direction and extend from face sheet to face sheet. Pin orientation and concentration can be varied providing a large design space for scientist and designer to explore and to improve material performance. The effect of core thickness, pin reinforcing and polymer foam core on the out-of-plane axial compression response of these panel will be presented. The through thickness three- point simply supported bending behavior of these reinforced panels is used to evaluate the core shear, stretch, face sheet failure characteristics of the structures. Explicit experimental observations are used to develop and calibrate analytical energy balance models to generate failure mode maps describing the panel collapse load as a function of geometry. Multi-scale effective modeling, blurring the distinction between structural and material behavior, will enable optimization of the X-cor sandwich structures in light of Yacht hull design requirements. The mechanical response of X-cor sandwich panels will be compared to current Yacht hull materials using material selection charts, and demonstrator components presented.