Academic literature on the topic 'Asymmetric info'
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Journal articles on the topic "Asymmetric info"
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Kuleshov, Sergey, Aleksandra Zaytseva, and Iliya Shalnev. "Distributed system of virtual machines for self-organized networks." Information and Control Systems, no. 5 (October 16, 2019): 30–37. http://dx.doi.org/10.31799/1684-8853-2019-5-30-37.
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Introduction: Active data, being fragments of executable code transmitted between the nodes of an active network, are an effectivemechanism for the operation of software-reconfigurable distributed systems. Previously, in the works devoted to active data, not enoughattention was paid to the implementation of the runtime environment (the processor) for the executable code of active data, as well asto the issues of building hypervisors and load balancing in distributed systems. Purpose: Developing principles for the construction of virtual machines with active data, providing the reconfigurability of the target devices and network flexibility in general. Evaluatingthe possibility of using the existing approaches to load balancing for networks with active data. Methods: Our study uses the principlesof software-defined system development, the conception of active data, theoretical foundations and technology of virtualization.Results: Is has been proposed to use a distributed system of virtual machines as an active data execution environment, based on theobject-oriented approach to creating distributed applications. Each node of such a distributed system of virtual machines can act aseither a control or slave node during the object interaction. Based on the developed approach, we proposed to solve the problem ofbuilding a network of repeaters using active data, considering an unmanned aerial vehicle as an element of an active info-communicationnetwork which supports the active data technology. Since a distributed system of virtual machines enables asymmetric distribution ofdecentralized network nodes, a method has been developed for a distributed system whose nodes are unmanned aerial vehicles and acontrol node, to control the asymmetry value by creating objects of various decomposition levels. Practical relevance: The proposedmethods provide a way to control the resource consumption of the nodes of a distributed software-reconfigurable network and theamount of network data transmitted. For dynamic management of the load on the network nodes, a resource manager architecture anda resource allocation algorithm are developed.
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Cai, Wenju, and Peter van Rensch. "Austral Summer Teleconnections of Indo-Pacific Variability: Their Nonlinearity and Impacts on Australian Climate." Journal of Climate 26, no. 9 (April 26, 2013): 2796–810. http://dx.doi.org/10.1175/jcli-d-12-00458.1.
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Abstract In austral summer, El Niño–Southern Oscillation (ENSO) covaries with the Indian Ocean Basin Mode (IOBM) and with the southern annular mode (SAM). The present study addresses how the IOBM and the SAM modulate the impact of ENSO on Australia. The authors show that the modulating effect of the SAM is limited; in particular, the SAM does not modify the ENSO teleconnection pattern. However, the IOBM extends ENSO-induced convection anomalies westward over northern Australia and over the eastern Indian Ocean, whereby extending the ENSO tropical teleconnection to the northwest of Australia. The IOBM also generates an equivalent-barotropic Rossby wave train through convection anomalies over northern Australia. The wave train shares an anomaly center over the Tasman Sea latitudes with the Pacific–South American (PSA) pattern, shifting the anomaly center of the PSA pattern to within a closer proximity to Australia. There is a strong asymmetry in the IOBM modulating effect. During an IOBM negative phase, which tends to coincide with La Niña events, the rainfall increase is far greater than the reduction during a positive IOBM phase, which tends to coincide with El Niño events. This modulation asymmetry is consistent with an asymmetry in the ENSO–rainfall teleconnection over Australia, in which the La Niña–rainfall teleconnection is stronger than the El Niño–rainfall teleconnection. This asymmetric ENSO–rainfall teleconnection ensures a higher coherence of northern Australia convective anomalies with La Niña or with a negative phase of the IOBM, hence a greater modification of the PSA pattern, underpinning the asymmetric modulating role of the IOBM.
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Ohba, Masamichi, and Masahiro Watanabe. "Role of the Indo-Pacific Interbasin Coupling in Predicting Asymmetric ENSO Transition and Duration." Journal of Climate 25, no. 9 (May 2012): 3321–35. http://dx.doi.org/10.1175/jcli-d-11-00409.1.
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Warm and cold phases of El Niño–Southern Oscillation (ENSO) exhibit a significant asymmetry in their transition/duration such that El Niño tends to shift rapidly to La Niña after the mature phase, whereas La Niña tends to persist for up to 2 yr. The possible role of sea surface temperature (SST) anomalies in the Indian Ocean (IO) in this ENSO asymmetry is investigated using a coupled general circulation model (CGCM). Decoupled-IO experiments are conducted to assess asymmetric IO feedbacks to the ongoing ENSO evolution in the Pacific. Identical-twin forecast experiments show that a coupling of the IO extends the skillful prediction of the ENSO warm phase by about one year, which was about 8 months in the absence of the IO coupling, in which a significant drop of the prediction skill around the boreal spring (known as the spring prediction barrier) is found. The effect of IO coupling on the predictability of the Pacific SST is significantly weaker in the decay phase of La Niña. Warm IO SST anomalies associated with El Niño enhance surface easterlies over the equatorial western Pacific and hence facilitate the El Niño decay. However, this mechanism cannot be applied to cold IO SST anomalies during La Niña. The result of these CGCM experiments estimates that approximately one-half of the ENSO asymmetry arises from the phase-dependent nature of the Indo-Pacific interbasin coupling.
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Gabriel, Ute, Pascal M. Gygax, and Elisabeth A. Kuhn. "Neutralising linguistic sexism: Promising but cumbersome?" Group Processes & Intergroup Relations 21, no. 5 (July 19, 2018): 844–58. http://dx.doi.org/10.1177/1368430218771742.
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The generic use of grammatically (or lexically) gender-marked nouns and pronouns (GM) to refer to women and men in Indo-European languages has been criticised as gender-asymmetric since the 1970s. Two main strategies for eliminating asymmetry have been suggested: visibility by feminisation and de-gendering by neutralisation. Feminisation strategies seek to contribute to women’s visibility in discourse by explicitly and symmetrically referring to women and men, thus continuing to highlight gender boundaries. In contrast, neutralisation strategies downplay gender boundaries by promoting the use of unmarked nouns and pronouns. We discuss feminisation and neutralisation strategies and review: (a) evidence (from our own work and that of others) on the effect of neutralisation and feminisation strategies on speakers’ and readers’ mental representations of gender and associated behaviours, and (b) evidence on individual variables facilitating and hampering the successful implementation of a less asymmetric—and therefore more gender-fair—language use. Based on this review, we suggest, in particular, to use feminisation strategies in contexts that are already gendered, and to use neutralisation strategies in nongendered ones (hence keeping the context gender-neutral).
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Feng, Juan, Jianping Li, Fred Kucharski, Yaqi Wang, Cheng Sun, Fei Xie, and Yun Yang. "Modulation of the Meridional Structures of the Indo-Pacific Warm Pool on the Response of the Hadley Circulation to Tropical SST." Journal of Climate 31, no. 21 (November 2018): 8971–84. http://dx.doi.org/10.1175/jcli-d-18-0305.1.
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By decomposing the variations of the Hadley circulation (HC) and tropical zonal-mean sea surface temperature (SST) into the equatorially asymmetric (HEA for HC, SEA for SST) and symmetric (HES for HC, SES for SST) components, the varying response of the HC to different SST meridional structures under warm and cold conditions of the Indo-Pacific warm pool (IPWP) is investigated over the period 1979–2016. The response of the HC to SST evidences an asymmetric variation between warm and cold IPWP conditions; that is, the response ratio of HEA to SEA relative to that of HES to SES is ~5 under warm conditions and ~2 under cold conditions. This asymmetry is primarily due to a decrease in the HEA-to-SEA ratio under cold IPWP conditions, and is driven by changes in the meridional distribution of SST anomalies. Equatorial asymmetric (symmetric) SST anomalies are dominated by warm (cold) IPWP conditions. Thus, variations of SEA are suppressed under cold IPWP conditions, contributing to the observed weakening of the HEA-to-SEA ratio. The results presented here indicate that the HC is more sensitive to the underlying SST when the IPWP is warmer, during which the variation of SEA is enhanced, suggesting a recent strengthening of the response of the HC to SST, as the IPWP has warmed over the past several decades, and highlighting the importance of the IPWP meridional structures rather than the overall warming of the HC.
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Ngonyani, Deo. "Sentential Negation and Verb Movement in Bantu Languages." Annual Meeting of the Berkeley Linguistics Society 28, no. 1 (August 14, 2002): 201. http://dx.doi.org/10.3765/bls.v28i1.3835.
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This paper explores a well-known asymmetry between negation marking main clauses and subordinate clauses in Bantu languages (Gilldemann 1999:551, Meeussen 1967:114). It is noted that pre-initial negation marking is usually restricted to main clauses, while post-initial marking is rarely restricted. Various studies have explored the diachronic origins of the various strategies. This paper focuses on how the strategies are constrained by clause structure. It is argued that negation projects a NegP as an element of Infl. Asymmetrical negation marking is due to two NegPs, one selecting TP, and the other selected by TP.
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Jacobsen, Ushma Chauhan. "Knowledge Asymmetry in Action." HERMES - Journal of Language and Communication in Business 27, no. 53 (December 2, 2014): 57. http://dx.doi.org/10.7146/hjlcb.v27i53.20950.
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<p align="LEFT">This article forges a connection between knowledge asymmetry and intercultural communication to challenge extant understandings of knowledge asymmetry as a static and stable condition that infl uences the processes and outcomes of interactive encounters that promote learning. The article draws its empirical material from ethnographic fieldwork at a training course on climate change that involved the participation of development practitioners, policy makers and civil servants working in broad professional arenas such as engineering, agriculture, water management and urban development in Sri Lanka, Kenya, Egypt, Bangladesh, Uganda, Tanzania, Vietnam and Denmark. The material is represented in the form of ethnographic vignettes to demonstrate knowledge asymmetry ‘in action’: how knowledge asymmetry is far from a static and stable condition, but rather how it emerges and disappears as participants summon, articulate, dismiss, ridicule, ignore or explore the rich pools of their culture/knowledge differences during the training course interaction. The article aligns itself to Barth’s (2002) conceptualization of culture as knowledge and to contemporary understandings of intercultural communication that privilege sensitivities to the webs of geo-historical relations and macro power and economic asymmetries that structure and inform intercultural relationships. The article also emphasizes the relevance of seeing knowledge asymmetry as a concept-metaphor (Moore 2004).</p>
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Lattari, Eduardo, Eduardo Portugal, Renato Sobral Monteiro Junior, Bruno Ribeiro Ramalho Oliveira, Tony Meireles Santos, Gioia Mura, Federica Sancassiani, et al. "Acute Affective Responses and Frontal Electroencephalographic Asymmetry to Prescribed and Self-selected Exercise." Clinical Practice & Epidemiology in Mental Health 12, no. 1 (October 31, 2016): 108–19. http://dx.doi.org/10.2174/1745017901612010108.
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Objective: Our goal was to compare affective responses and frontal electroencephalographic alpha asymmetry induced by prescribed exercise (PE) and self-selected exercise (SS). Method: Twenty active participants underwent a submaximal exercise test to estimate maximal oxygen consumption (VO2max). Participants enrolled a cross-over randomized study where each participant completed three conditions: PE (50%PVO2max), SS and Control. The electroencephalography was performed before and after exercise. The feeling scale, felt arousal scale and heart rate were recorded before, during and after each condition. The ratings of perceived exertion were recorded during and after each condition. Results: The heart rate and ratings of perceived exertion showed higher values in the PE and SS conditions compared to controls, with no differences between the PE and SS conditions. For the feeling scale, the SS presented higher values compared to the PE and Control conditions. The felt arousal scale presented higher values in the PE and SS conditions compared to control. There was no interaction between condition and moment, or main effect for condition and moment for frontal alpha asymmetry (InF4-InF3). Conclusion: The SS provided better affective responses compared to PE, thus can consider self-selected intensity as an appropriate option. In general, no frontal alpha asymmetry was seen due to an exercise intervention.
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Idrissa, Hama. "Profile of Congenital Cardiopathies in Paediatric Departments A and B of the National Hospital Niamey National Hospital (Research article)." Journal of Clinical Research and Reports 11, no. 4 (October 5, 2022): 01–06. http://dx.doi.org/10.31579/2690-1919/267.
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Aim: The aim of this study was to determine the extent of congenital heart disease in the population of children, for a better management and prevention strategy. Materials and Methods: This was a descriptive and cross-sectional study over a period of 4 years 10 months from January 2016 to October 2020 (retrospective over 4 years and prospective over 10 months) at the National Hospital of Niamey; Were included in our study all patients aged 0 to 21 with congenital heart disease confirmed by cardiac ultrasound who were hospitalized or monitored externally. Our data were analyzed by Epi Info software in version 7.2.2.6. 24. Descriptive and analytical statistics were used: the mean with standard deviation (SD) (for normal distributive variations), odds ratio (OR) and the median (Me) for the description of asymmetric distributive values. The comparison of the proportions was also carried out; to do this we used the statistical test of chi2. The test is significant if p <0.05 Results: The gender ratio was 1.005 in favour of men. The median age of our patients was 16.8 months with extremes ranging from 0 months to 247 months, the most represented age group is 29 days to 24 months with 81.1%. The majority of our patients (62.4%) came from urban areas, parental consanguinity was present in 42.2% of cases. 55.3% of our patients had reported a notion of recurrent respiratory infection. Respiratory distress was found in 29.5% of cases, followed by fatigue during feedings (16.7%). Tachycardia was found in 72.2% of our patients, 49.6% were undernourished. Heart murmur was found in 80.3% of our patients, 4.4% had Down's syndrome. Cardiomegaly was found in 64.4% of our patients, 15.7% had pulmonary hypervascularization. CIV was found in 27.03% followed by T4F, CAV, and CIA with 20.39 respectively; 17.20 and 16.95%. Surgery was indicated in 68.3%. Anemia was found in 55% of our patients, 49.6% had hyperleukocytosis. Antibiotic treatment was started in 72.7% of cases, 31.2% had benefited from diuretics, 23.8% from iron supplementation, 10.3% was on beta blockers. 18.7% had received surgical treatment, PAH and endocarditis were found in 1 and 0.73% of cases, respectively. 34.1% were awaiting surgery. The recorded death rate was 27.3%. Conclusion: Congenital heart disease is becoming more and more frequent and constitutes a very important health problem in our pediatric departments. They are dominated by CIVs and T4s. The diagnosis and their management are still difficult due to the lack of diagnostic and therapeutic means.
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Yates, Anthony D., and Sam Zukoff. "The phonology of Anatolian reduplication." Indo-European Linguistics 6, no. 1 (December 5, 2018): 201–70. http://dx.doi.org/10.1163/22125892-00601001.
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Abstract In this paper we develop a synchronic and diachronic analysis of the phonology of partial reduplication in the Anatolian branch of Indo-European. We argue that the reduplicative patterns of Hittite and Luwian differ from Proto-Anatolian, which exhibited an asymmetric treatment of verbal stems with initial consonant clusters: full copying of sibilant-stop clusters, but partial copying of stop-sonorant clusters. We contend that the phonological constraint driving this asymmetry, No Poorly-Cued Repetitions (Zukoff 2017a), was demoted within the separate prehistories of Hittite and Luwian due to independent phonological changes eliminating the distinction between these cluster types. Furthermore, we show that the proposed set of diachronic constraint re-rankings in Hittite and Luwian can be explained under Maximally Informative Recursive Constraint Demotion, a minor reformulation of the Recursive Constraint Demotion algorithm (RCD; Tesar 1995, Tesar and Smolensky 1998, 2000) that favors the high ranking of maximally informative winner-preferring constraints.
Dissertations / Theses on the topic "Asymmetric info"
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BONAZZI, LEDA MARIA. "Essays on Entry in Vertical Relationships." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/258913.
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Dall'inizio degli anni '90, i problemi di contrattazione verticale e le loro implicazioni sono stati ampiamente studiati nella letteratura dell'Organizzazione Industriale. Infatti, l'analisi della relazione tra mercati upstream e downstream è importante non solo per valutare l'impatto che le diverse forme di contratti hanno sul benessere totale e sul surplus del consumatore, ma anche per comprendere la caratterizzazione della struttura del mercato. Questa tesi è divisa in due capitoli riguardanti la contrattazione verticale e la struttura del mercato. Tenuto conto del fatto che sono presenti numerosi elementi che giocano un ruolo interessante, come la contrattazione sotto l'informazione asimmetrica, le decisioni di entrata e la scelta del mercato da parte delle imprese verticali, tutto il lavoro è orientato ad un’analisi di come questi elementi interagiscono tra loro e come le diverse forme di accordi contrattuali tra produttori e dettaglianti (two-part tariffs, i contratti lineari, la clausola di mantenimento dei prezzi di rivendita o il quantity forcing) influiscano sulle decisioni di ingresso e sulla scelta del mercato. Inoltre, una novità di questo articolo è considerare la struttura del mercato come endogena e studiare le conseguenze di questa ipotesi, aggiungendo nuove intuizioni a questo fiorente filone di letteratura.Since the beginning of 90's, vertical contracting issues and their implications have been widely studied in the Industrial Organization literature. For instance, analyzing the relationship between upstream and downstream markets is important not only to evaluate the impact that the different forms of vertical contracts have on total welfare and on consumer surplus, but also to better understand market structure. This thesis is organized in two chapters dealing with vertical contracting and market structure. Since, in this set-up there are many elements playing an interesting role, like contracting under asymmetric information, entry decisions and market choice by vertical related firm, throughout the work there is an analysis of how these elements interact between each others, and how different forms of contractual agreements between manufacturers and retailers, as two-part tariffs, resale price maintenance and quantity forcing, affect entry decisions and market choice. A novelty of this thesis is to consider market structure as endogenous and to study the consequences of this assumption, by adding new insights to the burgeoning existing literature on entry in vertical relationships.
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Bena, Luvuyo Clifford. "Investigations into the asymmetric reduction of ketones." Thesis, University of Port Elizabeth, 2003. http://hdl.handle.net/10948/323.
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A six-step synthesis of salbutamol from methyl salicylate with an overall yield of 17% has been completed, although the yield was not optimised. In the process, Zn(BH4)2 was found to selectively reduce a ketone carbonyl group in the presence of an ester unit. In contrast, borane was found to reduce both the ketone and ester carbonyl groups. Reduction of phenacyl bromide with borane in the presence of chiral catalysts based on (R)-alaninol and (R,S)-ephidrine resulted a measure of enantioselectivity in the product. However, the configuration of the alcohol obtained in the case of (R)-alaninol was contrary to expectations based both on experimental trends observed elsewhere as well as our own theoretical predictions. The asymmetric reduction of methyl 5-bromoacetyl-2-benzyloxybenzoate was accomplished with both borane and Zn(BH4)2 in the presence of a range of chiral catalysts. Optically active products were obtained in all cases, although the optical rotations were significantly smaller in the case of Zn(BH4)2. Unfortunately, we were not successful in determining the enantiomeric excesses of these reactions. The use of a NMR lanthanide shift reagent resulted in a complex spectrum that was impossible to interpret unambiguously. This presumably arises from the presence of several Lewis base sites in the product at which complexation with the shift reagent can take place. It was also not possible to determine the optical rotation of salbutamol itself owing to the relatively small amount of material obtained. A conformational analysis of salbutamol, where NMR data was correlated with molecular modelling results, was successfully carried out and revealed a strong preference for that conformer family characterised by O–C–C–N and Ar–C–C–N torsion angles of ca. 60º and 180º, respectively. Interestingly, these conformers are found to be stabilised by OH…N rather than NH…O hydrogen bonding. This study has also confirmed the effectiveness of the MMFF94 force field for conformational analysis studies in compounds of this kind. Lastly, a relatively simple method for modelling the BH3/oxazaborolidine reduction of ketones at the PM3 semiempirical MO level of approximation was devised. This approach has provided insights into the mechanism of the reaction and has furthermore enabled us to predict the enantioselectivities likely to result from various catalysts and ketones. In comparing our theoretical and experimental findings, an anomalous result was observed in the case of (R)-alaninol; this will have to be investigated further, particularly at the experimental level. However, we believe that our approach provides a sound basis for aiding the design and screening of new, potentially better catalysts.
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Evans, Gareth J. S. "Theoretical investigation into asymmetric iminium ion organocatalysis." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/55527/.
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The scope of this thesis covered three main areas of this emerging area of chemistry. A reaction pathway is proposed for the formation of iminium ion intermediates from the reaction of secondary amines with carbonyl compounds. This suggests the deprotonation of the amine as the rate-determining step. The effect of modification of amine structure on this pathway was studied, and rationalised using Atoms-in-Molecules analysis. Molecular properties were used to describe a range of secondary amines with an aim to find a relationship between composition and reactivity. A number of catalytic candidates were suggested for synthesis. Two reaction types that directly and indirectly utilise iminium ions as catalysts or intermediates were covered. This included studies of model amines, as well as those in current use as asymmetric catalysts. The Diels-Alder reaction was studied in depth for a number of iminium ions. The alpha-acyloxylation of enamines was also studied, and reaction profiles in gas-phase and solvent identified, and possible mechanisms of asymmetric induction explored.
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Jankowski, Piotr. "New insights into asymmetric hydrogenation using monodentate phosphorus ligands." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551301.
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The synthesis and coordination chemistry of monodentate phosphorus ligands that span a range of stereoelectronic effects is the topic of this thesis. It is shown that many Rh complexes of the type [Rh(L)2(olefin)]BF4 (L = ligand) exhibit restricted Rh-P bond rotation, which is slow enough to be observed on the NMR timescale. Variable temperature NMR studies of a range of Rh complexes of mono ph os ligands reveal similarities in the observed pattern, suggesting that the M-P restricted rotation is a more general phenomenon of the cis-ligated square planar complexes. OFT calculations and solid state analysis are employed to shed light on the structures of the Cl- and C2-symmetrical rotamers observed in the NMR spectra. The improvement of the separation of enantiomers of optically active 1,3,5,7- tetramethyl-4,6,8-trioxa-2-phospha-adamantane, CgPH is reported, allowing the recovery of the previously inaccessible a-CgPH. Optically active a-CgPH yields a highly selective catalyst in the asymmetric hydrogenation of various olefins, producing ee of up to 95%. Rh complexes of CgPH are extensively studied by NMR techniques and OFT calculations in order to understand the unexpectedly high enantioselectivity obtained with Rh-CgPH catalysts; it is proposed that the enantioselectivity arises from the presence of a Cl-symmetrical rotamer in solution. A series of 3,3' -dimethylphosphonite ligands of a type (binolate)PR (R = Me, iPr, Cy, tBu) are synthesised and their coordination chemistry is investigated. Most of the ligands upon reaction with [Rh(cod)2]BF 4 produce complexes of a type [Rh(L)2(cod)]BF4• The tBu-phosphonite does not follow this reactivity pattern, presumably due to the steric bulk of the ligand, making the incorporation of two ligands in the cis arrangement unfavourable. Of all the above mentioned ligands, the iPr- and Cy-phosphonite are the best catalysts for the hydrogenation of a- dehydroaminoacid derivative substrates, methyl-(Z)-a-acetamidocinnamate (up to 94%) and methyl-a-acetamidoacrylate (up to 97%), but they are less selective for dimethylitaconate (up to 75%). A series of ligands bearing extended aromatic systems are synthesised in order to probe the possibility of the backbone formation using pi-pi interactions in cis square planar complexes. Some circumstantial evidence for the interactions have been observed and the presence of the extended pi systems is shown not to be beneficial on the asymmetric hydrogenation outcome.
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Bowman, Iain Niall Reginald. "A study of mass injection into an asymmetric supersonic wake." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386256.
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Mazloumi, Khatebeh. "An investigation into a series of asymmetric intramolecular Nicholas cyclisation reactions." Thesis, Kingston University, 2013. http://eprints.kingston.ac.uk/27740/.
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The Nicholas reaction is the reaction of a cobalt-stabilised propargyl cation with a nucleophile and the aim of this project was to attempt this reaction with a chiral substrate in an effort to effect an asymmetric Nicholas reaction. A range of contemporary techniques were applied to reach this goal. Initially an attempt was made to reproduce an earlier successful racemic synthesis of a fused carbocyclic compound using a chiral precursor. It was envisaged that this would be approached using a 1,4-conjugate addition to an enone using a chiral ligand to install the C-3 alkenyl group selectively. Although the conjugate addition reactions were successful, using well tried and tested ligands, the enantiomeric excesses were very low and unfortunately a suitable chelating catalyst that prevent fulfil the requirements was not identified at this stage of the investigation. The next approach made use of an asymmetric alkynylation reaction to an aldehyde. This was successfully carried out using a Carreira asymmetric alkynylation reaction to afford optically active propargyl alcohols with good to excellent enantiomeric excess (50%-82% ees). The desired optical active propargyl alcohols were then complexed, with dicobalt octacarbonyl, to afford the corresponding dicobalt hexacarbonyl complexes. These then successfully underwent the corresponding Nicholas cyclisation reaction to afford, after oxidative decomplexation of the cobalt species, a range of optically active chromane and isochromanes with ees of (45%-81%). In a second study a series of optically active benzopyran derivatives were also successfully synthesised, using the same methodology, again with high levels of enantiomeric excess (87% - 94%). In the final phase of this investigations it was explored the use of chiral derivatives of the chiral pool molecule citronellal as well as an achiral analogue in an effort to afford novel chiral aldehydes for propargylation and cyclisation. The new chiral centres were successfully installed using chiral auxiliary technology however unexpectedly difficulties were encountered in the removal of the chiral auxiliary. A lack of time, in order to further explore the removal step, unfortunately meant that this was put on hold for further studies.
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Valette, Damien. "Studies into asymmetric Diels-Alder reactions of anthracene derivatives using cationic oxazaborolidines." Thesis, University of Sheffield, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544175.
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Brawn, Peter. "An investigation into the asymmetric synthesis of novel benzopyrans for biological evaluation." Thesis, Kingston University, 2012. http://eprints.kingston.ac.uk/24046/.
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The aim of this project was to prepare a novel range of dicobalt hexacarbonyl-alkyne complexes for testing as anticancer agents and benzopyrans as antihypertensives. In addition an investigating into the stereoselectivity of the Nicholas reaction will be undetaken. Hypertension and cancer are two very different dieases that are becoming more prevalent in modern life. Interest in antiproliferatory compounds containing metallic substituents has intensified since the serendipitous discovery of cisplatin in 1969. More recently Co-ASS, a dicobalt hexacarbonyl alkyne complex derived from aspirin, was found to out perform Cisplatin in the inhibition of MCF-7 breast cancer cells. This has led to a number of cobalt-alkyne complexes being found to possess anticancer activity. The preparation of a range novel cobalt-alkyne complexes is herein described along with the testing of their efficacy against CaCo-2 cancer cells. This Study showed that the presence of aromatic ring substituents had a large detrimental effect on their activity with the unsubstituted counterpart eliciting an IC50 value of 16.02 µM relative to >100 µM for the substituted counterparts. The observed IC50 of 16.02 is similar to those found in the literature for the cobalt-alkyne complexes of propargyl amides Co-ASSAM and Co-Phthal giving values of 8.8 and 22.2 repectively on MCF-7 cells. Benzopyrans are known to relax smooth muscle by activating transmembrane potassium channels. Cromakalim, the bench mark potassium channel activator however is not used clinically due to undesirable side effects. This has led to a large amount of work into the preparation of novel benzopyrans that maintain this activity whilst eliminating these side effects. Although the novel benzopyrans prepared were shown to be less active, as vasorelaxants, compared to cromakalim, they do, show greater activity compared to compounds that had been previously prepared within the Tyrrell group. Finally we show the exclusive cis diastereoselective nature of our studied Nicholas reaction in the simultaneous formation of two chiral centres. The effect of chiral induction on the formation of these two centres is also investigated showing the ee of the Nicholas reaction to be >99% and a de of 68% in the most selective instance.
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Lamping, Logan Joseph. "An investigation into an asymmetric fuel nozzle in a GE CFM56-5B burner." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/12061.
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Cornish, Alix. "Investigations into chiral adsorption systems relevant to asymmetric heterogeneous catalysis on metal surfaces." Thesis, University of Reading, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553037.
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Two chiral adsorption systems are investigated, adsorption of a known chiral modifier, alanine, onto Ni surfaces and the interaction of chiral homoserine on intrinsically chiral Cu {531}. Alanine is known to act as a chiral modifier in the enantioselective hydrogenation of ~-ketoesters, but the reaction mechanism has yet to be determined. Two approaches are employed to investigate how alanine acts as a chiral modifier. Adsorption onto single crystal Ni{111} and {11O} surfaces is studied by XPS and angle resolved NEXAFS. It was shown that in the chemisorbed layer, alanine adsorbs in an anionic state with a deprotonated carboxylate group on both surfaces. This arrangement was also observed for achiral glycine on Ni {Ill}. A triangular adsorption footprint is created with surface bonds between both carboxylate oxygen atoms and the amino nitrogen. The growth of zwitterionc multi layer alanine is also observed for both systems but on Ni{11O} the multi layer is shown to segregate into alanine crystallites with a Stranskiy-Krastanov-like morphology at 240 K. On Ni {111}, the tilt angle of the carboxylate group from the surface is 45' compared to 55' on the Ni {Il O}, determined by angle resolved NEXAFS. Decomposition of these amino acids is shown to proceed via initial cleavage of the Ca-COO bond to release CO2 followed by cleavage of the Ca-CH3 bond to ultimately produce (Hx)C=N and atomic carbon. On the Ni {11O} surface, these final decomposition products coexist until -700 K whereas on Ni {Ill} only atomic species exist on the surface after 450 K, for both alanine and glycine. Ultimately, the atomic N recombines to form N2 which is detected by TPD at mass 28 and 14 amu. The second approach involved alanine adsorption on polycrystalline Ni. Previous experiments to probe this system had either been performed in UHV on single crystal surfaces, or in solution based studies with high surface area catalyst particles. This complexity gap is a poignant problem in the attempt to understand the mechanistic details of this reaction. Polycrystals were seen as a bridge between these two systems since they offer several different surface terminations and boundaries, which are analogous to reactive, defect sites on catalyst particles. PEEM and LEEM were successfully used to identify the surface facets of polycrystalline Ni and allowed the application of several surface science techniques. The oxidation of poly crystalline Ni is successfully probed using PEEM and LEEM. For oxygen exposure at temperatures of 473 K and higher, spatially resolved NEXAFS spectra clearly identify NiO crystallites in the I urn range with areas of clean Ni surface between them. Certain boundary regions are devoid of crystalIites. For lower temperatures a uniform chemisorbed oxygen layer with a different spectroscopic signature is formed. The same technique was applied to study alanine adsorption. It is shown that alanine is capable of restructuring grain boundaries of polycrystalline Ni, possibly creating chiral facets, where the enantioselective reaction could occur. The adsorption of homoserine on chiral Cu{531} was performed to improve our understanding of the interactions between chiral molecules and chiral substrates, specifically, the influence of longer side chains. XPS and angle resolved NEXAFS experiments were performed to probe enantiomeric differences. Homoserine was found to exist on the surface in an anionic state involving a deprotonated carboxylate group and a neutral amino group. It was found that three surface bonds are always made, one from the amino nitrogen and one from each of the carboxylate oxygen atoms, creating a triangular footprint, typical for a-amino acids. Under certain conditions; 50% saturation coverage of D-homoserine and also 85 and 100% saturation coverage of L- homoserine, the alcohol side chain makes an additional bond to the surface via the oxygen atom, creating a rectangular footprint. Both enantiomers are shown to occupy both adsorption sites equally but a 12' rotational difference in adsorption between the two enantiomers is found to exist for low coverages.
Books on the topic "Asymmetric info"
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North, Jill. Time in Thermodynamics. Edited by Craig Callender. Oxford University Press, 2011. http://dx.doi.org/10.1093/oxfordhb/9780199298204.003.0011.
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It is often claimed, or hoped, that some temporal asymmetries are explained by the thermodynamic asymmetry in time. Thermodynamics, the macroscopic physics of pressure, temperature, volume, and so on, describes many temporally asymmetric processes. Heat flows spontaneously from hot objects to cold objects (in closed systems), never the reverse. More generally, systems spontaneously move from non-equilibrium states to equilibrium states, never the reverse. Delving into the foundations of statistical mechanics, this chapter reviews the many open questions in that field as they relate to temporal asymmetry. Taking a stand on many of them, it tackles questions about the nature of probabilities, the role of boundary conditions, and even the nature and scope of statistical mechanics.
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Renic, Neil C. Asymmetric Killing. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198851462.001.0001.
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This book offers an engaging and historically informed account of the moral challenge of radically asymmetric violence—warfare conducted by one party in the near-complete absence of physical risk, across the full scope of a conflict zone. What role does physical risk and material threat play in the justifications for killing in war? And crucially, is there a point at which battlefield violence becomes so one-directional as to undermine the moral basis for its use? In order to answers these questions, Asymmetric Killing delves into the morally contested terrain of the warrior ethos and Just War Tradition, locating the historical and contemporary role of reciprocal risk within both. This book also engages two historical episodes of battlefield asymmetry, military sniping and manned aerial bombing. Both modes of violence generated an imbalance of risk between opponents so profound as to call into question their permissibility. These now-resolved controversies will then be contrasted with the UAV-exclusive violence of the United States, robotic killing conducted in the absence of a significant military ground presence in conflict theatres such as Pakistan, Yemen, and Somalia. As will be revealed, the radical asymmetry of this latter case is distinct, undermining reciprocal risk at the structural level of war. Beyond its more resolvable tension with the warrior ethos, UAV-exclusive violence represents a fundamental challenge to the very coherence of the moral justifications for killing in war.
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Zagajewski, Adam. Asymmetry. FSG Adult, 2019.
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Zagajewski, Adam. Asymmetry: Poems. Farrar, Straus & Giroux, 2018.
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Zagajewski, Adam. Asymmetry: Poems. Farrar, Straus and Giroux, 2018.
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Knight, Alec. An Asymmetric Comparative International Law Approach to Treaty Interpretation. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190697570.003.0020.
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This chapter illustrates an asymmetric comparative international law approach to treaty interpretation through the example of the CEDAW Committee’s greater willingness to go beyond a margin of appreciation to tolerate progressive deviations rather than regressive deviations in the interpretation of CEDAW’s provisions. Section I examines the interactions between the CEDAW Committee and states parties. Section II discusses how the Committee’s asymmetric approach to treaty interpretation fits within a comparative international law project. Section III provides an introduction to the CEDAW Committee. Section IV illustrates the CEDAW Committee’s inflexible treatment of Muslim states parties’ reservations to the Convention, which constitute regressive deviations. Section V analyzes the Committee’s permissive treatment of the Scandinavian approach to CEDAW. Section VI explores how the asymmetric approach allows states to develop interpretations of treaties. Section VII concludes and describes potential future avenues of research into the asymmetric comparative international law approach to treaty interpretation.
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Hoerl, Christoph, Teresa McCormack, and Alison Fernandes, eds. Temporal Asymmetries in Philosophy and Psychology. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780198862901.001.0001.
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Humans’ attitudes towards an event often vary depending on whether the event has already happened or has yet to take place. The dread felt at the thought of a forthcoming examination turns into relief once it is over. People also value past events less than future ones—offering less pay for work already carried out than for the same work to be carried out in the future, as recent research in psychology shows. This volume brings together philosophers and psychologists with a shared interest in such psychological past/future asymmetries. It asks questions such as: What different kinds of psychological past/future asymmetries are there, and how are they related? Under what conditions do humans exhibit them? To what extent do they reflect features of time itself, or particular beliefs people have about time? Are they rational, or at least rationally permissible, or should we aspire to being temporally neutral? What exactly does temporal neutrality consist in?
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Kachelriess, Michael. Baryogenesis. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198802877.003.0022.
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This chapter shows that a baryon asymmetry can be generated only if the Sakharov conditions are satisfied. The required departure from thermal equilibrium can be realised either in first-order phase transitions or in out-of-equilibrium decays. Sphaleron transitions as a possible way to transfer a lepton into a baryon asymmetry are covered and the Boltzmann equation governing the baryon asymmetry generated in particle decays is derived. A brief review of baryogenesis during the electroweak phase transition is presented.
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Maher, Kristen Hill, and David Carruthers. Unequal Neighbors. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197557198.001.0001.
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San Diego and Tijuana are the site of a national border enforcement spectacle, but they are also neighboring cities with deeply intertwined histories, cultures, and economies. In Unequal Neighbors: Place Stigma and the Making of a Local Border, Kristen Hill Maher and David Carruthers shift attention from the national border to a local one, examining the role of place stigma in reinforcing actual and imagined inequalities between these cities. Widespread “bordered imaginaries” in San Diego represent it as a place of economic vitality, safety, and order, while stigmatizing Tijuana as a zone of poverty, crime, and corruption. These dualisms misrepresent complex realities on the ground, but they also have real material effects: the vision of a local border benefits some actors in the region while undermining others. Based on a wide range of original empirical materials, the book examines how asymmetries between these cities have been produced and reinforced through stigmatizing representations of Tijuana in media, everyday talk, economic relations, and local tourism discourse and practices. However, both place stigma and borders are subject to contestation, and the study also examines “debordering” practices and counternarratives about Tijuana’s image. While the details of the study are particular to this corner of the world, the processes it documents offer a window into the making of unequal neighbors more broadly. The dynamics of this case present a framework for understanding how inequalities between places rest in part on cultural practices that produce asymmetric borders.
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Marmodoro, Anna. Aristotelian Powers at Work. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198796572.003.0005.
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This paper puts powers to work by developing a broadly Aristotelian account of causation, built on the fundamental idea (which Aristotle found in Plato, attributed by him to Heraclitus) that causation is a mutual interaction between powers. On this Aristotelian view, causal powers manifest them-selves in dependence on the manifestation of their mutual partners. (See also Heil, this volume; Mumford, this volume; and Martin 2008.) The manifestations of two causal power partners are co-determined, co-varying, and co-extensive in time. (See Marmodoro 2006.) Yet, causation has a direction and is thus asymmetric. This asymmetry is what underpins metaphysically the distinction between causal agent and patient. The proposed Aristotelian analysis of the interaction between mutually manifesting causal powers is distinctive, in that it pays justice to the intuition that there is agency in causation. That is, agency is not a metaphorical way of describing what causal powers do. For some powers, it is a way of being that instantiates the non-anthropomorphic sense in which powers are causal agents. This point is brought out in the paper in relation to the explanation of the concept of change. In an Aristotelian fashion, the paper argues that the distinction be-tween agent and patient in causation is pivotal to offering a realist account of causation that does not reify the interaction of the reciprocal causal partners into a relation. On the proposed view, the interaction between mutually manifesting causal partners consists in the power of one substance being realized in another substance. Specifically, the agent’s causal powers metaphysically belong to the agent, but come to be realized in the patient. The significance of this is that the interaction of the agent’s and the patient’s powers is not a relation; rather, it is an ex-tension of the constitution of the agent onto the patient, which occurs when agent and patient interact and their powers are mutually manifested. Thus the proposed Aristotelian account of causation explains the mutual interaction between manifestation partners—potentiality, agency, and change—as irreducible to one another, but interconnected.
Book chapters on the topic "Asymmetric info"
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Ojala, Jari. "Maritime Information Networks between Northern and Southern Europe during the Eighteenth century." In Atti delle «Settimane di Studi» e altri Convegni, 183–94. Florence: Firenze University Press, 2019. http://dx.doi.org/10.36253/978-88-6453-857-0.10.
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International trade during the 18th century is a case in point through which to study in-depth the challenges of asymmetric information. The challenges can be divided into three categories: availability, reliability and usability of information. This article discusses the organization of trade and shipping between Northern and Southern Europe. The access, reliability and use of information were problems for merchant-shipowners during the 18th century. The solutions adopted were partly contradictory: the aim to reduce information asymmetry on one determinant, might incur costs on the other.
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Andrade, Neelam N., Paul Mathai, and Neha Aggarwal. "Facial Asymmetry." In Oral and Maxillofacial Surgery for the Clinician, 1549–76. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-1346-6_70.
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AbstractAny abnormality of the soft or hard tissues of the face can lead to asymmetry. This could be a consequence of a congenital anomaly, a developmental or an acquired defect. Asymmetry can be progressive in nature, while those acquired due to trauma or ablative surgeries are non- progressive. It is prudent for the clinician to consider the aetiology of the asymmetry, the extent and its severity in all three dimensions in order to provide an optimal treatment plan. Besides, it is important to take into consideration factors such as growth, timing of treatment and psychological aspirations of the patients. The present chapter will discuss the etiopathogenesis and classifications, clinical considerations and diagnosis, evaluation and treatment planning of facial asymmetries. Few interesting case scenarios will also be discussed for a better understanding of clinical presentations and various surgical procedures available for management.
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Šunjić, Vitomir, and Vesna Petrović Peroković. "Stereoisomers and Stereoselective Reactions—“Departure into Third Dimension”." In Organic Chemistry from Retrosynthesis to Asymmetric Synthesis, 51–66. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-29926-6_3.
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Alexander, Nicholas A., Faiz A. Noor, and Khalid Javed. "Response of asymmetric buildings to ground motion phase component." In Seismic Design Practice into the Next Century, 99–106. London: Routledge, 2022. http://dx.doi.org/10.1201/9780203740026-14.
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Alexander, Nicholas A., Faiz A. Noor, and Khalid Javed. "Response of asymmetric buildings to ground motion phase component." In Seismic Design Practice into the Next Century, 99–106. London: Routledge, 2022. http://dx.doi.org/10.1201/9780203740026-14.
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Alexander, Nicholas A., Faiz A. Noor, and Khalid Javed. "Response of asymmetric buildings to ground motion phase component." In Seismic Design Practice into the Next Century, 99–106. London: Routledge, 2022. http://dx.doi.org/10.1201/9780203740026-14.
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Anshul Khandelwal, Kamal Poddar, and Debopam Das. "Investigations into Asymmetric Oscillations of a Symmetric Airfoil." In Fluid Mechanics and Fluid Power – Contemporary Research, 185–94. New Delhi: Springer India, 2016. http://dx.doi.org/10.1007/978-81-322-2743-4_19.
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Adomeit, Hannes. "Russia’s Strategic Outlook and Policies: What Role for China?" In Russia-China Relations, 17–39. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97012-3_2.
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AbstractThis examination deals with the mental maps and basic assumptions underlying Russia’s foreign policy and how these relate to China. I will take issue with the narrative, advanced in particular by Kremlin officials and pro-Putin apologists in the West, that Russia’s “pivot to Asia,” with China as its centerpiece, can be understood as the consequence of the West having rejected Putin’s outstretched hand for close cooperation, Russia’s exclusion from an all-European security structure by pushing NATO’s eastward expansion, and finally the imposition of economic sanctions. This, to complete the account, had left Russia with no other option but to turn to Asia. Such interpretations will be shown to be fundamentally flawed. Putin’s China policies fit squarely into both the Russian power elite’s global strategic outlook and its narrow perception of what is needed to hold on to power domestically. The benefits accruing to Russia from its liaison with China can be found in military, economic, and systemic dimensions, and they are for the most part asymmetric in favor of the Kremlin. The asymmetries may cause problems in the future, but for the time being, they are carefully managed so that they will not spin out of control.
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Konstantinidis, Stavros, Mitja Mastnak, and Juraj Šebej. "Partitioning a Symmetric Rational Relation into Two Asymmetric Rational Relations." In Implementation and Application of Automata, 171–83. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-23679-3_14.
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Wiktor, Jan W., and Katarzyna Sanak-Kosmowska. "Trends in further research into information asymmetry in online advertising and the manipulation of e-consumer behaviour." In Information Asymmetry in Online Advertising, 190–200. London: Routledge, 2021. http://dx.doi.org/10.4324/9781003134121-12.
Full textConference papers on the topic "Asymmetric info"
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He, Qifan, and Mohammed F. Daqaq. "Influence of Potential Function Asymmetries on the Performance of Nonlinear Energy Harvesters Under White Noise." In ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-34397.
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To improve the broadband transduction capabilities of vibratory energy harvesters (VEHs) under random and non-stationary excitations, many researchers have resorted to purposefully introducing nonlinearities into the restoring force of the harvester. While performing this task, it is often very challenging to maintain a perfectly symmetric restoring force which usually yields a VEH with an asymmetric potential energy function. This paper investigates the influence of potential function asymmetries on the performance of nonlinear VEHs under white noise inputs. To that end, a quadratic nonlinearity is introduced into the restoring force of the harvester and its influence on the mean power for both mono- and bi-stable potentials is investigated. It is shown that, for VEHs with a mono-stable potential function, the mean output power increases with the degree of potential function asymmetry. On the other hand, for energy harvesters with a bi-stable potential function, asymmetries in the restoring force appear to worsen performance especially for low to moderate noise intensities. When the noise intensity becomes sufficiently large, the influence of the potential function’s asymmetry on the mean power diminishes. Results also reveal that a VEH with a symmetric bi-stable potential function produces higher mean power levels than the one with the most asymmetric mono-stable potential. As such, it is concluded that a VEH with a bi-stable symmetric potential is most desirable to improve performance under white noise.
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Kim, Geunsoo, and Limei Peng. "Asymmetric service provisioning in elastic optical networks." In 2017 International Conference on Information and Communications (ICIC). IEEE, 2017. http://dx.doi.org/10.1109/infoc.2017.8001666.
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Faucher, Colette, and Malika Machtoune. "PSYMDEV, a System Intended for Assisting the Military Analyst to Construct Psychological Messages." In Applied Human Factors and Ergonomics Conference. AHFE International, 2019. http://dx.doi.org/10.54941/ahfe100196.
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In asymmetric conflicts, the Armed Forces generally have to intervene in countries where the internal peace is in danger. They must make the local population an ally in order for them to be able to deploy the necessary military actions with its support. For this purpose, psychological operations (PSYOPS) are used to shape people’s behaviors and feelings by spreading out messages thanks to different media (tracts, loudspeakers, video clips, etc.). In this paper, we present PSYMDEV (PSYchological Message DEViser), a system that helps the military analyst to construct messages that trigger specific feelings in members of the population selected by social criteria like age or political opinion and called the info-targets. Given such a sociocultural group and a feeling that the latter must feel, the system provides a twofold-situation that consists of, on the one hand, a categorization-situation meant to induce a positive or negative initial state of mind in the info-targets depending on the type of feeling to be triggered through a psychological mechanism inspired by theories stemming from Social Psychology and an action-situation aiming at effectively triggering the specific feeling through a psychological process explained by the Intergroup Emotion Theory, an extension of the Appraisal Theory of Emotions. These situations are illustrated by means of images or a film or some auditive elements, thanks to adapted media generally used by the military like tracts or video clips, for example. Therefore, the twofold-situation gives birth to a psychological message intended to trigger a feeling. After presenting the theories underlying the system and its overall structure and functioning, we more specifically focus on the conception of a categorization-situation.
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Yang, C. C., and Alex J. S. Wang. "Logic functions using asymmetric nonlinear coupling at a fiber coupler." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.wu5.
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Although nonlinear coupling at a coupler has been widely studied for all-optical ultrafast switching, use of nonlinear coupling for logic functions has not been reported. In this paper, the phenomena of asymmetric nonlinear coupling at a fiber coupler are presented. By asymmetric nonlinear coupler, we mean a coupler in which the Kerr effects in the two waveguides are different when the same power is launched into each waveguide. The difference in Kerr effect can be implemented by controlling the nonlinear constant or waveguide thickness. Although the nonlinear effect is asymmetric in such a coupler, linear coupling is still symmetric, otherwise energy cannot be conserved. It is found that, in the chosen range of coupler asymmetry, input energy tends to appear in the waveguide of larger nonlinearity at the output end of a half beat-length coupler when only one waveguide is excited. When both waveguides are excited, the energy distribution between the two output ports depend on the relative phase of the two input signals. By appropriately choosing the coupler asymmetry and the relative phase of the input signals, nor, and, or. and xor gates are implemented using a half beat-length coupler.
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Pray, Carl M., and Stephen A. Hambric. "Finite Element Study of Harmonic Forcing Function Scattering Mechanisms for Cylindrical Structures." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32686.
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Low frequency sound radiation from cylindrical structures is generally dominated by radiation from low order (M=0, 1) circumferential harmonic modes. The high order circumferential harmonic modes are inefficient radiators below the coincidence frequency. For cylindrical structures excited by low frequency, high circumferential order (e.g. N=10) forcing functions, the radiated sound will be dominated by radiation from the low order modes if the forcing function is scattered by structural asymmetries into these modes. In this study, cylindrical structures of varying levels of asymmetry are examined using finite element analysis to quantify the scattering of order N harmonic forcing functions into order M structural response harmonics. First, purely axially-symmetric structures are examined to verify the analysis method used. The models examined include a finite cylinder with constant cross-section and a finite cylinder with tapered cross-section. The constant cross-section cylinder is analyzed in vacuo, and the tapered cylinder is analyzed both in vacuo and with water loading. These structures show no harmonic scattering, as would be expected. Next, a finite tapered cylinder with cyclically symmetric impedance discontinuities and a finite tapered cylinder with an asymmetric large impedance discontinuities are analyzed, both with water loading, to determine the impact of structural discontinuity on the harmonic scattering and radiated sound spectra. The periodic and single discontinuities both show significant scattering into low order circumferential modes and corresponding increases in radiated sound.
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Tripathi, Abhinav, and Zongxuan Sun. "Nonlinear Feedforward Control for Electrohydraulic Actuators With Asymmetric Piston Areas." In ASME 2016 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/dscc2016-9721.
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This paper presents a new design method of a nonlinear feedforward controller for electrohydraulic actuators with asymmetric piston areas. While the use of flatness based inversion of the plant model to design a feedforward controller has been reported for electrohydraulic actuators with symmetric piston area, the extension of this method to actuators with asymmetric piston areas is non-trivial. In asymmetric electrohydraulic actuators, the areas of the hydraulic piston are different in the two chambers, and hence, the amount of fluid going into one chamber of the actuator is not equal to the amount of fluid coming out of the other. This asymmetry leads to loss of flatness, and hence, flatness based inversion of the plant is no longer possible. In this paper, we present a method for calculation of the feedforward control signal for a given trajectory by numerically solving the inverse problem for the system. We demonstrate the effectiveness of the proposed feedforward controller by simulation of trajectory tracking in an asymmetric electrohydraulic actuator. For benchmarking, the tracking performance has been compared with three other feedforward schemes: a linearized model based Zero Phase Error Tracking (ZPET) feedforward controller, a nonlinear feedforward controller implementing an approximate plant inversion based on differential flatness, and a pressure feedback based feedforward controller.
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Yılmaz, Tufan Gürkan, Oğuz Doğan, Celalettin Yüce, and Fatih Karpat. "Improvement of Loading Capacity of Internal Spur Gear With Using Asymmetric Trochoid Profile." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71009.
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Today, with numerous advantages such as reduced sliding velocity and wear, higher transmission ratio, higher running efficiency etc., internal spur gears are used in several industrial applications. An internal gear is generated by pinion cutters towards inside of gear blank opposite of external gear. In this study, bending stress of internal spur gear with the asymmetric trochoid profile is investigated. Asymmetry is ensured by using pinion cutter has different tip radius value on its right and left side. This situation is allowed to use larger tip radius on one side. The limit value of tip radius is defined with taking into account cutter addendum height and interference possibility for the given pinion gear parameters. On the other side, asymmetry on the involute region is also examined. Firstly, a mathematical equation of pinion cutter is derived then points of internal gear are obtained by using coordinate transformation, differential geometry and gearing theory in MATLAB. Points of internal gear are exported to CATIA to realize the 3D design. Case studies are conducted for determining the relation between tip radius and pressure angle on bending stress separately with ANSYS program. According to preliminary results, using asymmetric trochoid profile reduces approximately 16% bending stress of internal spur gear.
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Hegde, Shreyas, Laith Zori, Rubens Campregher, and Robert Kielb. "Impact of Aerodynamic Asymmetry on the Embedded Rotor Forcing and Mistuned Blade Response." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-78101.
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Abstract This paper continues previous research by the current authors in a series of papers describing the impact of multi-row interaction on the forced response behavior of embedded compressor rotors. Specifically, this work dives into an aspect of the embedded rotor forcing that has been sparsely addressed in literature — the impact of an asymmetry in the upstream stator on the forcing function and blade vibration. Although the concept of introducing an asymmetry was introduced nearly 50 years ago, no papers in literature talk about the impact of multi-row interaction with an upstream asymmetric stator in place. All of the current authors’ previous work has discussed the impact of symmetric stators exciting a rotor upstream and downstream. This impact has been quantified at multiple torsional mode crossing some of which result in one-half of the asymmetric stator exciting the rotor and a crossing which results in the downstream stator exciting the rotor. Due to the inability of model reduction methods to model this phenomenon, full wheel computational domains were utilized for all simulations. A commercial code CFX was used for all simulations. In all of the multi-row cases investigated, only a single row excites the rotor. The additional downstream row serves as a reflecting wall that reflects physical waves, which leads to interference. The second section of this paper describes the details of the in-house mistuning code utilized to predict the blade responses of the individual rotor blades in the system. One of the inputs to this code is the modal force obtained using unsteady CFD in the paper’s first section. The in-house code is based on the FMM, which couples both aero and structural dynamics to predict the blade responses. The key conclusions from this study were: 1) An asymmetry in the upstream stator results in a significant reduction in the forcing function at the crossing frequency. However, the magnitude of forcing could remain significant with a shift to a ‘sideband’ frequency. 2) Introducing an asymmetry is beneficial only when the asymmetric stator excites the rotor and not when any of the other rows excites the rotor. 3) The impact of physical wave reflections was constructive at all torsional mode crossings in line with the earlier conclusions. 4) The mistuned response was well predicted by the FMM at all crossings despite the presence of significant blade disk interaction at these crossings.
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Dunklin, Jeremy R., Gregory T. Forcherio, Keith R. Berry, and D. Keith Roper. "Asymmetric gold nanoparticle reduction into polydimethylsiloxane thin films." In SPIE NanoScience + Engineering, edited by Allan D. Boardman. SPIE, 2014. http://dx.doi.org/10.1117/12.2061908.
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Geatches, Rachel M., Susan V. Dewar, and Richard V. Penty. "Vertical couplers: all-optical switch design." In Nonlinear Optics: Materials, Fundamentals and Applications. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/nlo.1996.nme.1.
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Nonlinear directional couplers (NLDCs) have been shown to have great potential as the basis for all-optical switching devices (reviewed, for example by Agrawal and Boyd [1]). The potential for nonlinear switching has been demonstrated in InGaAsP NLDCs, by utilizing resonant non-linearities near the band gap, i.e., λ = 1.55μm, thereby requiring moderate switching powers [2]. However, the required swiching power is higher than that ideally required for semiconductor laser optical sources and so it is important that this is minimised. Significant reductions in switching power have been predicted in coupled fibers with asymmetric configurations when compared to corresponding symmetric designs [3]. Chen et al also forecast further reductions in switching power by matching gain in one guide to loss in the other. We have studied the design of asymmetric semiconductor couplers, where the coupling is finely balanced, and predict the switching power to be substantially reduced when compared with symmetric designs. These investigations are now being extended to vertical configurations, which are expected to have significant advantages over the more conventional horizontal designs. By adopting a vertical configuration, the waveguiding regions can be realistically closer together, thereby reducing the coupling length, which will allow for a minimum of loss over the distance required for switching. Furthermore, the geometrical asymmetry of the coupler can be maximized, by coupling a planar-guide to a rib-guide. Likewise material asymmetry can be introduced easily into a vertical configuration. Finally, by having the guides in different planes, the doping requirements needed for biasing in order to induce gain (at transparency), can be more easily realised.
Reports on the topic "Asymmetric info"
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Halling, Alfred Mike, Xian Ping Lu, and /Fermilab. Observation of the Coalescing of Beam Into an Asymmetric RF Bucket by Stochastic Cooling. Office of Scientific and Technical Information (OSTI), January 1993. http://dx.doi.org/10.2172/984615.
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Razin, Assaf, Efraim Sadka, and Chi-Wa Yuen. Channeling Domestic Savings into Productive Investment Under Asymmetric Information: The Essential Role of Foreign Direct Investment. Cambridge, MA: National Bureau of Economic Research, December 1997. http://dx.doi.org/10.3386/w6338.
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Thompson, Joshua M. Measurement of CP-Violating Asymmetries In Neutral B Meson Decays Into Three Kaons. Office of Scientific and Technical Information (OSTI), December 2008. http://dx.doi.org/10.2172/943483.
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Chang, Darwin. CP Asymmetry in the Higgs Decay into the Top Pair Due to the Stop Mixing. Office of Scientific and Technical Information (OSTI), July 2001. http://dx.doi.org/10.2172/784960.
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Dallapiccola, Carlo. Measurement of Branching Fractions and Search for CP-violating Charge Asymmetries in Charmless Two-body B Decays into Pions and Kaons. Office of Scientific and Technical Information (OSTI), July 2001. http://dx.doi.org/10.2172/787183.
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Kucherova, Hanna, Anastasiia Didenko, Olena Kravets, Yuliia Honcharenko, and Aleksandr Uchitel. Scenario forecasting information transparency of subjects' under uncertainty and development of the knowledge economy. [б. в.], October 2020. http://dx.doi.org/10.31812/123456789/4469.
Full textAbstract:
Topicality of modeling information transparency is determined by the influence it has on the effectiveness of management decisions made by an economic entity in the context of uncertainty and information asymmetry. It has been found that information transparency is a poorly structured category which acts as a qualitative characteristic of information and at certain levels forms an additional spectrum of properties of the information that has been adequately perceived or processed. As a result of structuring knowledge about the factor environment, a fuzzy cognitive model of information transparency was constructed in the form of a weighted digraph. Structural analysis and scenario forecasting of optimal alternatives of the fuzzy cognitive model made it possible to evaluate the classes of factors, identify their limited relations, establish the centrality of the roles of information transparency and information and communication security in the system built and evaluate their importance when modeling the situation self-development. Information visibility, reliability and availability have been found to have the strongest impact on the system. Taking into account different initial weights of the key factors — information transparency and information and communication security — the study substantiates the strategic ways for economic entities to achieve their goals in the context of uncertainty and information asymmetry, which allows us to use this approach as a tool for strategic management in the information environment.
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Goeckeritz, Joel, Nathan Schank, Ryan L Wood, Beverly L Roeder, and Alonzo D Cook. Use of Urinary Bladder Matrix Conduits in a Rat Model of Sciatic Nerve Regeneration after Nerve Transection Injury. Science Repository, December 2022. http://dx.doi.org/10.31487/j.rgm.2022.03.01.
Full textAbstract:
Previous research has demonstrated the use of single-channel porcine-derived urinary bladder matrix (UBM) conduits in segmental-loss, peripheral nerve repairs as comparable to criterion-standard nerve autografts. This study aimed to replicate and expand upon this research with additional novel UBM conduits and coupled therapies. Fifty-four Wistar Albino rats were divided into 6 groups, and each underwent a surgical neurectomy to remove a 7-millimeter section of the sciatic nerve. Bridging of this nerve gap and treatment for each group was as follows: i) reverse autograft—the segmented nerve was reversed 180 degrees and used to reconnect the proximal and distal nerve stumps; ii) the nerve gap was bridged via a silicone conduit; iii) a single-channel UBM conduit; iv) a multi-channel UBM conduit; v) a single-channel UBM conduit identical to group 3 coupled with fortnightly transcutaneous electrical nerve stimulation (TENS); vi) or, a multi-channel UBM conduit identical to group 4 coupled with fortnightly TENS. The extent of nerve recovery was assessed by behavioural parameters: foot fault asymmetry scoring measured weekly for six weeks; electrophysiological parameters: compound muscle action potential (CMAP) amplitudes, measured at weeks 0 and 6; and morphological parameters: total fascicle areas, myelinated fiber counts, fiber densities, and fiber sizes measured at week 6. All the above parameters demonstrated recovery of the test groups (3-6) as being either comparable or less than that of reverse autograft, but none were shown to outperform reverse autograft. As such, UBM conduits may yet prove to be an effective treatment to repair relatively short segmental peripheral nerve injuries, but further research is required to demonstrate greater efficacy over nerve autografts.
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Goeckeritz, Joel, Nathan Schank, Ryan L Wood, Beverly L Roeder, and Alonzo D Cook. Use of Urinary Bladder Matrix Conduits in a Rat Model of Sciatic Nerve Regeneration after Nerve Transection Injury. Science Repository, December 2022. http://dx.doi.org/10.31487/j.rgm.2022.03.01.sup.
Full textAbstract:
Previous research has demonstrated the use of single-channel porcine-derived urinary bladder matrix (UBM) conduits in segmental-loss, peripheral nerve repairs as comparable to criterion-standard nerve autografts. This study aimed to replicate and expand upon this research with additional novel UBM conduits and coupled therapies. Fifty-four Wistar Albino rats were divided into 6 groups, and each underwent a surgical neurectomy to remove a 7-millimeter section of the sciatic nerve. Bridging of this nerve gap and treatment for each group was as follows: i) reverse autograft—the segmented nerve was reversed 180 degrees and used to reconnect the proximal and distal nerve stumps; ii) the nerve gap was bridged via a silicone conduit; iii) a single-channel UBM conduit; iv) a multi-channel UBM conduit; v) a single-channel UBM conduit identical to group 3 coupled with fortnightly transcutaneous electrical nerve stimulation (TENS); vi) or, a multi-channel UBM conduit identical to group 4 coupled with fortnightly TENS. The extent of nerve recovery was assessed by behavioural parameters: foot fault asymmetry scoring measured weekly for six weeks; electrophysiological parameters: compound muscle action potential (CMAP) amplitudes, measured at weeks 0 and 6; and morphological parameters: total fascicle areas, myelinated fiber counts, fiber densities, and fiber sizes measured at week 6. All the above parameters demonstrated recovery of the test groups (3-6) as being either comparable or less than that of reverse autograft, but none were shown to outperform reverse autograft. As such, UBM conduits may yet prove to be an effective treatment to repair relatively short segmental peripheral nerve injuries, but further research is required to demonstrate greater efficacy over nerve autografts.