State-space realization of a describing function

The describing function is a powerful tool for characterizing nonlinear dynamical systems in the frequency domain. In some cases, it is the only available description of a nonlinear operator characterizing a certain subcomponent of the system. This paper presents a methodology to provide a state-space realization of one given describing function, in order to allow the study of the system in the time domain as well. The realization is based on Hammerstein models and Fourier–Bessel series. It can be embedded in time domain simulations of complex configurations with many nonlinear elements interacting, accurately describing the nonlinear saturation of the system. The technique is applied to an example application in the field of combustion instability, featuring self-excited thermoacoustic oscillations. We benchmark the performance of the tool comparing the results with a frequency domain analysis of the same system, obtaining good agreement between the two formulations.This work was supported by the European Research Council through project ALORS N.259620 and by the German Research Association for Combustion Engines (Forschungsvereinigung Verbrennungskraftmaschinen e.V. FVV).This is the accepted manuscript of a paper published in Nonlinear Dynamics (Ghirardo G, Ćosić B, Juniper MP, Moeck JP, Nonlinear Dynamics, 2015, doi:10.1007/s11071-015-2134-x). The final version is available at http://dx.doi.org/10.1007/s11071-015-2134-

Metastability – Markovian approach

A complete system of events of nonlinear processes in complex dynamical systems describes the evolution of the distribution. Different stages of evolution of the distribution declared stable, metastable and unstable systems. Variance of probabilistic distribution plays a crucial role in determining the state of the system. It was found that the system is metastable, when it carried Markovian processes in continuous time. Metastability is the original metallurgical phenomenon and actively exists in the structure of the materials. In a metastable state, the structural distances in material are exponentially distributed

Construction of the discourse on reality and its paradigms in Germany and Romania between the two world wars. Echoes in literature and culture Построение дискурса реальности и ее парадигмы в Германии и Румынии между двумя мировыми войнами. Отголоски в литературе и культуре

Međuratni period u Evropi je dao potencijal za konstrukciju ekstremizovanih diskursa o stvarnosti. Uprkos obimnim istorijskim istraživanjima, sličnosti u diskursu Nemačke i Rumunije, kao i uloga pojedinca u njemu, ostali su nedovoljno ispitani. Diskurs o stvarnosti predstavlja metadiskurs, koji ekstremizacijom postaje ideologija, koja, kao društveno-politički metadiskurs, nameće istorijsku i metaistorijsku analizu stvarnosti. Razmatramo imagološki aspekt diskursa o stvarnosti, slične identitarne modele i identitarnu propagandu u dve zemlje, i to kroz njihovu interakciju sa književnošću. Prva hipoteza pretpostavlja sličnosti i/ili razlike u konstrukciji uokvirenih nacionalističkih paradigmi u sličnim ideološko-političkim i kulturnim uslovima. Druga hipoteza sagledava odnos cenzura – sloboda, koji vodi do sličnih shvatanja uloge književnog autora i njegovog stvaralačkog identiteta u različitim kulturama. Pristup je multidisciplinaran, a istraživani domeni za konstrukciju diskursa o stvarnosti su kultura, književnost, istorija, mit, obrazovanje i cenzura sa propagandom. Odjeci promena u ovim domenima prikazani su kroz književna dela koja reflektuju diskurs o stvarnosti, zbog čega se na njih kratko osvrćemo, a neka podrobnije analiziramo. Dodatno, komparativnom metodom se predstavljaju slične ili različite tendencije, koje su ekstremizovale poimanje identiteta. Uočena su preslikavanja transkulturoloških modela u datom istorijskom periodu u Nemačkoj i Rumuniji: dominantne revolucionarne tendencije su putem ekstremizacije konstruisale gotovo identične diskurse o stvarnosti, koristeći različite narative. Rezultati ukazuju na važnost uloge i stepen odgovornosti pojedinca, pogotovo u turbulentnim periodima, i otvaraju nova interesantna pitanja za dalja istraživanja.The interwar period in Europe largely contributed to the construction of an extreme discourse of reality. Despite extensive historical research, the similarities in the discourse of Germany and Romania, as well as the role of the individual in it, remain insufficiently examined. The discourse of reality represents a meta-discourse, which, through extremism, becomes an ideology that, as a socio-political meta-discourse, imposes a historical and metahistorical analysis of reality. We investigate the imagological aspect of such discourses of reality, similar identity models and identity propaganda in the two countries, all through their interaction with literature. The first hypothesis presupposes similarities and/or differences in the construction of pre-set nationalist paradigms in similar ideological-political and cultural conditions. The second hypothesis observes the relationship between censorship and freedom, which leads to similar perceptions of the role of literary authors and their creative identity in different cultures. The approach is multidisciplinary, and the researched domains for the constructed discourse of reality are culture, literature, history, myth, education, and censorship with propaganda. The echoes of changes in these domains are presented through literary works that reflect the discourse, which is why we either look at them briefly or analyze them in more detail. In addition, the comparative method reveals similar or different tendencies, which caused the extremization of the perception of identity. The mapping of transcultural models in the given historical period is observed in these different countries: the dominant revolutionary tendencies through their extremism shaped almost identical discourses of reality, using different narratives. The results emphasize the importance and responsibility of the individual, especially in turbulent periods, and open new intriguing questions for further research

A model for the pavement temperature prediction at specified depth

This paper examines the existing models for predicting pavement temperatures at a certain depth and formulates a new one using the regression equation to predict the minimum and maximum pavement temperatures at the specified depth depending on the surface pavement temperature and its depth

Probing problems and priorities in oral health (care) among community dwelling elderly in the Netherlands: a mixed method study

Background: Complex dentitions and decline in adequate oral hygiene in elderly may lead to poor oral health. This may have impact on their general health, wellbeing and quality of life. With increased longevity, the problems and needs in oral health of community dwelling elderly lead to changes in oral health care needs. We identified and prioritized problems and needs in oral health of community dwelling elderly. Methods: The problems and needs in oral health of community dwelling elderly were elicited during focus groups and interviews. The list of problems and needs derived thereof was presented to 97 elderly who prioritized these. Results: Overall, older people appeared to be satisfied with their current oral health, and the maintenance and care for their oral health. Cost of care was identified as a major problem in general. There are differences in current perceived problems and needs and problems and needs anticipated for the future. Perceived current problems and needs concern dental care provision and knowledge on oral health of professionals and patients. For anticipated future problems and needs the importance of daily oral care by caregivers was prioritised, while emphasis was placed on fear of losing autonomy. Conclusion: It is important to take the perspectives and expectations of elderly into account in policy and planning of future oral health care practice, because these differ from the perspectives of dental professionals

Quantum Rainbows in Positron Transmission through Carbon Nanotubes

Here we report the results of the theoretical investigation of the transmission of channeled positrons through various short chiral single walled carbon nanotubes (SWCNT). The main question answered by this study is “What are the manifestations of the rainbow effect in the channeling of quantum particles that happens during the channeling of classical particles?” To answer this question, the corresponding classical and quantum problems were solved in parallel, critically examined, and compared with each other. Positron energies were taken to be 1 MeV when the quantum approach was necessary. The continuum positron-nanotube potential was constructed from the thermally averaged Molière’s positron-carbon potential. In the classical approach, a positron beam is considered as an ensemble of noninteracting particles. In the quantum approach, it is considered as an ensemble of noninteracting wave packages. Distributions of transmitted positrons were constructed from the numerical solutions of Newton’s equation and the time-dependent Schrödinger equation. For the transmission of 1-MeV positrons through 200-nm long SWCNT (14; 4), in addition to the central maximum, the quantum angular distribution has a prominent peak pair (close to the classical rainbows) and two smaller peaks pairs. We have shown that even though the semiclassical approximation is not strictly applicable it is useful for explanation of the observed behavior. In vicinity of the most prominent peak, i.e., the primary rainbow peak, rays interfere constructively. On one of its sides, rays become complex, which explains the exponential decay of the probability density in that region. On the other side, the ray interference alternates between constructive and destructive, thus generating two observed supernumerary rainbow peaks. The developed model was then applied for the explanation of the angular distributions of 1-MeV positrons transmitting through 200 nm long (7, 3), (8, 5), (9, 7), (14, 4), (16, 5) and (17, 7) SWCNTs. It has been shown that this explains most but not all rainbow patterns. Therefore, a new method for the identification and classification of quantum rainbows was developed relying only on the morphological properties of the positron wave function amplitude and the phase function families. This led to a detailed explanation of the way the quantum rainbows are generated. All wave packets wrinkle due to their internal focusing in a mutually coordinated way and are concentrated near the position of the corresponding classical rainbow. This explanation is general and applicable to the investigations of quantum effects occurring in various other atomic collision processes

Lipoprotein(a) Is the Best Single Marker in Assessing Unstable Angina Pectoris

This study evaluated whether statin therapy changed a diagnostic validity of lipid and inflammatory markers in ischemic heart disease (IHD) patients. Levels of lipids, lipoproteins, apolipoproteins, inflammatory markers, and atherogenic indexes were determined in 49 apparently healthy men and women, 82 patients having stable angina pectoris (SAP), 80 patients with unstable angina (USAP), and 106 patients with acute ST-elevation myocardial infarction (STEMI) treated or not treated with statins. Diagnostic accuracy of markers was determined by ROC curve analysis. Significantly lower apoA-I in all statin-treated groups and significantly higher apoB in statin-treated STEMI group compared to non-statin-treated groups were observed. CRP showed the best ROC characteristics in the assessment of STEMI patients. Lp(a) is better in the evaluation of SAP and USAP patients, considering that Lp(a) showed the highest area under the curve (AUC). Regarding atherogenic indexes, the highest AUC in SAP group was obtained for TG/apoB and in USAP and STEMI patients for TG/HDL-c. Statins lowered total cholesterol, LDL-c, and TG but fail to normalize apoA-I in patients with IHD

Evaluation of inverted-pendulum-with-rigid-legs walking locomotion models for civil engineering applications

This is the final version. Available from MDPI via the DOI in this record. Data Availability Statement: Data are contained within the article.Bipedal models for walkers, originally developed in the research field of biomechanics, have been identified as potential candidates for modelling pedestrians in structural engineering applications. These models provide insight into both the kinetics and kinematics of walking locomotion and are considered to have a significant potential to improve the vibration serviceability assessment of civil engineering structures. Despite this notion, the ability of the bipedal models to represent the key features of the walking gait and natural variability within the pedestrian population are still under-researched. This paper critically evaluates the performance of two bipedal models with rigid legs to realistically both reproduce key features of an individual pedestrian’s walking gait and represent a wide range of individuals. The evaluation is performed for walking on a rigid, rather than vibrating, structure due to the availability of experimental data and expectation that successful modelling on rigid surfaces is a necessary condition for progressing towards modelling on the vibrating structures. Ready-to-use equations are provided and the ability of the models to represent the kinematics and kinetics of individual pedestrians as well as the inter-subject variability typical of the human population is critically evaluated. It was found that the two models could generate realistic combinations of the gait parameters and their correlations, but are less successful in reproducing genuine kinetic and kinematics profiles.Engineering and Physical Sciences Research CouncilEngineering and Physical Sciences Research CouncilEuropean Union’s Horizon 2020China Scholarship Counci