The Extreme Function Theory for Damage Detection: An Application to Civil and Aerospace Structures

Any damaged condition is a rare occurrence for mechanical systems, as it is very unlikely to be observed. Thus, it represents an extreme deviation from the median of its probability distribution. It is, therefore, necessary to apply proper statistical solutions, i.e., Rare Event Modelling (REM). The classic tool for this aim is the Extreme Value Theory (EVT), which deals with uni- or multivariate scalar values. The Extreme Function Theory (EFT), on the other hand, is defined by enlarging the fundamental EVT concepts to whole functions. When combined with Gaussian Process Regression (GPR), the EFT is perfectly suited for mode shape-based outlier detection. In fact, it is possible to investigate the structure’s normal modes as a whole rather than focusing on their constituent data points, with quantifiable advantages. This provides a useful tool for Structural Health Monitoring, especially to reduce false alarms. This recently proposed methodology is here tested and validated both numerically and experimentally for different examples coming from Civil and Aerospace Engineering applications. One-dimensional beamlike elements with several boundary conditions are considered, as well as a two-dimensional plate-like spar and a frame structure.

Molecular bases of primary monogenic dyslipidemia

Дислипидемия - одно из наиболее распространенных метаболических нарушений, доминирующий фактор риска заболеваний сердечно-сосудистой системы. Своевременная диагностика и корректировка липидного профиля могут заметно снизить заболеваемость и смертность от сердечно-сосудистых заболеваний. Обширная гетерогенная группа заболеваний приводит к устойчивым изменениям липидного профиля. Предлагаемый обзор включает в себя описание метаболизма липидов, молекулярных основ и клинических характеристик первичных моногенных дислипидемий. Мутации двадцати пяти генов являются причиной большинства моногенных дислипидемий. На основании изменений липидного профиля выделяют пять групп фенотипов с экстремальным отклонением уровней маркеров липидного профиля: с высоким и низким уровнем липопротеинов низкой плотности, с высоким и низким уровнем липопротеинов высокой плотности, с высоким уровнем триглицеридов. Для каждого фенотипа обозначены ассоциированные гены, указан ген с чаще всего выявляемыми мутациями. Подробно описаны молекулярные основы наиболее распространенной дислипидемии, характеризующейся существенным повышением уровня липопротеинов низкой плотности - семейной гиперхолестеринемии. Генетическое тестирование пациентов с дислипидемией дает возможность постановки точного диагноза, каскадного обследования и консультирования членов семьи пациента, ранней диагностики для предотвращения или более позднего проявления осложнений. Dyslipidemia is one of the most common metabolic disorders, the dominant risk factor for diseases of the cardiovascular system. Timely diagnosis and correction of the lipid profile can significantly reduce morbidity and mortality from cardiovascular diseases. An extensive heterogeneous group of diseases leads to persistent changes in the lipid profile. This review includes a description of lipid metabolism, the molecular basis, and clinical characteristics of primary monogenic dyslipidemia. Mutations in twenty-five genes are responsible for most monogenic dyslipidemias. On the basis of changes in the lipid profile, five groups of phenotypes are distinguished with extreme deviation in the levels of lipid profile markers: with high and low levels of low density lipoproteins, with high and low levels of high density lipoproteins, with high levels of triglycerides. For each phenotype, the associated genes are indicated, the gene with the most frequently detected mutations is indicated. The molecular basis of the most common dyslipidemia, familial hypercholesterolemia, is described in detail. Genetic testing of patients with dyslipidemia makes it possible to make an accurate diagnosis, the possibility of cascade examination and counseling of the patient’s family members, the possibility of early diagnosis to prevent or later manifest complications.

Statistical method of estimation of stability of parameters of rotor blades of steam turbines of thermal power plants during manufacturing and testing

The paper is devoted to relevant issue of raising the quality and reliability of rotor blades of steam turbines. This is due to the fact that the number of failures of rotor blades exceeds 60% of all failures of steam turbines, which are in operation. The developed method of control of stability of parameters and reliability of rotor blades during their manufacturing and testing is proposed to introduce in addition to the existing method of quality control of rotor blades of steam turbines. The methods of quality control of rotor blades during the process of their manufacturing and testing according to existing normative documentation are described in detail. The form 1 “List of defects, malfunctions and failures, which have been revealed during manufacturing and testing” and form 2 “Inspection chart of stability of parameters” have been developed in addition to normative documentation. The calculation equations for estimation of stability of parameters of technological processes and reliability level have been presented. A technique for determination of extreme deviation of parameters and regulation boundaries according to preset tolerance has been developed. An example of stability control of natural oscillation frequency has been presented. The presented technique has been implemented at special purpose enterprises. An internal certificate is drawn up for each set of rotor blades at the manufacturing plant with a view to gather statistical information. This certificate is developed by the manufacturer. Information about the material certificate, the results of control, which has been carried out during the process of manufacturing and testing, with indication of deviations from the draft, the technical specifications during the testing, the description of technological process of thermal treatment of stocks etc. are noted down in the internal certificate.

Research on Cutting Remanufacture Hardness Deposited Materials in the Impactive Condition

High performance cemented carbide YG610 was adopted for remanufacture hardness deposited materials cutting experiment. The experiment results showed that the same conclusions can be drawn from two group orthogonal experiments. The influence order on cutting capability of cutting tools was: feed rate﹥cutting speed﹥ cutting depth. The cutting length of cutting tools increases monotonously with the feed rate decrease. And the effects by the cutting depth were comparatively small, which is almost negligible in hardness materials cutting. Therefore，low feed rate and large depth of cut are beneficial to keep cutting capability of cutting tools and improve manufacturing productivity. By the results of two orthogonal experiments and extreme deviation analysis, the optimal scheme for cutting parameters were achieved after calculating the best level of the factor.

Taylor Rule and the Macroeconomic Performance in Pakistan

A near-consensus position in modern macroeconomics is that policy rules have greater advantage over discretion in improving economic performance. For developing countries in particular, simple instrument rules appear to be feasible options as pre-requisites since more sophisticated targeting rules are generally lacking. Using Pakistan’s data, this study has attempted to estimate the Taylor rule and use it as monetary policy strategy to simulate the economy. Our results indicate that the State Bank of Pakistan (SBP) has not been following the Taylor rule. In fact, the actual policy has been an extreme deviation from it. On the other hand, counterfactual simulation confirms that macroeconomic performance could have been better in terms of stability of inflation and output, had the Taylor rule been adopted as monetary policy strategy. The study also establishes that further gains are possible if the parameter values of the rule are slightly modified. JEL classification: E47, E31, E52 Keywords: Taylor Rule, Macroeconomic Performance, Counterfactual Simulation

Development and the fragmented self: Longitudinal study of dissociative symptomatology in a nonclinical sample

Dissociative behaviors and their relation to both the self and self-organization were examined using the developmental psychopathology perspective in a prospective longitudinal study of high-risk children. Participants were 168 young adults (n = 79 females, n = 89 males, age = 18–19 years) considered high-risk for poor developmental outcomes at birth due to poverty. The present study investigated whether trauma, sense of self, quality of early mother–child relationship, temperament, and intelligence were related to dissociative symptomatology measured at four times across 19 years. Findings were (a) age of onset, chronicity and severity of trauma were highly correlated and predicted level of dissociation; (b) both the avoidant and disorganized patterns of attachment were strong predictors of dissociation; (c) dissociation in childhood may be a more normative response to disruption and stress, while dissociation in adolescence and young adulthood may be more indicative of psychopathology; (d) preliminary support was found for a model proposed by G. Liotti that links disorganized attachment, later trauma, and dissociation in adulthood; and (e) strong support was found for N. Waller, F. W. Putnam, and E. B. Carlson's contention that psychopathological dissociation should not be viewed as the top end of a continuum of dissociative symptomatology, but as a separate taxon that represents an extreme deviation from normal development.