An Annular Plate Model in Arbitrary-Lagrangian-Eulerian Description for the DLR FlexibleBodies Library

The bending deformation of rotating annular plates and the associated vibration behaviour is important in engineering applications which range from automotive or railway brake systems to discs that form essential components in turbomachinery. In order to extend the capabilities of the DLR FlexibleBodies library for such use cases, a new Modelica class has been implemented which is based on the analytical description of an annular Kirchhoff plate. In addition the so-called Arbitray Langrangian-Eulerian (ALE) representation has been adopted so that rotating and non-rotating external loads may be applied conventiently to rotating plates. Besides these particularities the new class AnnularPlate completely corresponds to the concept of FlexibleBodies library with the two already available model classes Beam and ModalBody. This paper gives an overview on the theoretical background of the new class AnnularPlate, explains the usage and presents application examples

A Thermo-elastic Annular Plate Model for the Modeling of Brake Systems

The friction forces generated during braking between brake pads and discs produce high thermal gradients on the rubbing surfaces. These thermal gradients may cause braking problems such as brake fade, premature wear or hot spotting and the associated hot judder phenomenon in the frequency range below 100 Hz. Further consequences are comfort reductions, a defective braking process, inhomogeneous wear, cutbacks of the brake performance and even damage of brake components. The present paper proposes a modeling concept that is targeted on this field of application and introduces the new Modelica class ThermoelasticPlate, which is implemented in the DLR FlexibleBodies library

Undisturbed climbing fiber pruning in the cerebellar cortex of CX3CR1-deficient mice

Pruning, the elimination of excess synapses is a phenomenon of fundamental importance for correct wiring of the central nervous system. The establishment of the cerebellar climbing fiber (CF)-to-Purkinje cell (PC) synapse provides a suitable model to study pruning and pruning-relevant processes during early postnatal development. Until now, the role of microglia in pruning remains under intense investigation. Here, we analyzed migration of microglia into the cerebellar cortex during early postnatal development and their possible contribution to the elimination of CF-to-PC synapses. Microglia enrich in the PC layer at pruning-relevant time points giving rise to the possibility that microglia are actively involved in synaptic pruning. We investigated the contribution of microglial fractalkine (CX3CR1) signaling during postnatal development using genetic ablation of the CX3CR1 receptor and an in-depth histological analysis of the cerebellar cortex. We found an aberrant migration of microglia into the granule and the molecular layer. By electrophysiological analysis, we show that defective fractalkine signaling and the associated migration deficits neither affect the pruning of excess CFs nor the development of functional parallel fiber and inhibitory synapses with PCs. These findings indicate that CX3CR1 signaling is not mandatory for correct cerebellar circuit formation. Main Points - Ablation of CX3CR1 results in a transient migration defect in cerebellar microglia. - CX3CR1 is not required for functional pruning of cerebellar climbing fibers. - Functional inhibitory and parallel fiber synapse development with Purkinje cells is undisturbed in CX3CR1-deficient mice

Будівництво комплексу породного перевантаження дренажних пластів с5 і с6 шахти ім. Сташкова ВСП «ШУ ДНІПРОВСЬКЕ» ПрАТ «ДТЕК ПАВЛОГРАДВУГІЛЛЯ»

Пояснювальна записка: 89 с, 3 рис, 13 табл., 1 додаток, 8 джерел. ШАХТА ІМ. СТАШКОВА, ШТРЕК, ЖИВИЛЬНИК, НІША, БУНКЕР, КОМБАЙН, БУРОПІДРИВНІ РОБОТИ, КУТ НАХИЛУ ВИРОБКИ Об’єкт розроблення – спорудження комплексу виробок породного перевантаження шахти ім. Сташкова. Мета роботи – визначення параметрів технології спорудження комплексу виробок і обґрунтування геометричних параметрів бункеру, а саме – раціонального кута нахилу виробки. Результати та їх новизна – обґрунтування кута нахилу виробки з використанням засобів механіки тіла і теорії удару елементів гірської маси по кріпленню виробки. Новизна рішень полягає в запропонованій схемі проходки бункеру, яка містить два етапи: розбурювання передової свердловини і наступного розширення виробки буро підривним способом, що дозволяє забезпечити безпеку праці і скоротити витрати праці прохідників. Взаємозв’язок з іншими роботами – розвиток наукових тем, які стосуються питань оптимізації показників ефективності проходки, спорудження виробок і їх захисту для довготривалого використання в рамках наукових робот, які виконуються на кафедрі будівництва, геотехніки і геомеханіки Національного технічного університету «Дніпровська політехніка». Сфера застосування розробки – технології спорудження похилих і вертикальних виробок в умовах шахт Західного Донбасу. Практична значимість кваліфікаційної роботи – використання запропонованих рішень для реального будівництва комплексу виробок на шахті ім. Сташкова.Explanatory note: 89 c, 3 fig,, 13 table, 1 app, 8 sources. STASHKOVA MINE, DRIFT, FEEDER, NICHE, BUNKER, HARVESTER, DRILLING AND BLASTING WORK, WORKING ANGLE The fragmentation facility is equipped with a complex of workings of rock reexcavation of the Stashkova mine. The purpose of the work is to determine the parameters of the technology of construction of the complex of workings and substantiation of the geometrical parameters of the hopper, namely - the rational angle of inclination of the workings. The results and their novelty - justification of the angle of inclination of the workpiece with the use of body mechanics and the theory of impact of the elements of the rock mass on the roof. The novelty of the solution lies in the proposed scheme for the passage of the hopper, which contains two steps: the destruction of the advanced well and the subsequent expansion of the production of the drill in a disruptive way, which allows to ensure safety and reduce the cost of labor of the passers. Interconnection with other works - development of scientific topics related to optimization of indicators of drilling efficiency, construction of workings and their protection for long-term use within the framework of scientific works performed at the Department of Construction, Geotechnics and Geomechanics of the National Technical University "Dniprovska Polytechnic." Scope of development - technology of construction of inclined and vertical workings in the conditions of mines of Western Donbass. The practical significance of the qualification work - the use of the proposed solutions for the real construction of a complex of workings at the mine. Stashkova

A Dirac theorem for trestles *

Abstract A k-subtrestle in a graph G is a 2-connected subgraph of G of maximum degree at most k. We prove a lower bound on the order of a largest ksubtrestle of G, in terms of k and the minimum degree of G. A corollary of our result is that every 2-connected graph with n vertices and minimum degree at least 2n/(k + 2) contains a spanning k-subtrestle. This corollary is an extension of Dirac's Theorem

Bedside Measurement of Volatile Organic Compounds in the Atmosphere of Neonatal Incubators Using Ion Mobility Spectrometry

Background: Early and non-invasive diagnosis of common diseases is of great importance in the care of preterm infants. We hypothesized that volatile organic compounds (VOC) can be successfully measured in the neonatal incubator atmosphere. Methods: This is a feasibility study to investigate whether the discrimination of occupied and unoccupied neonatal incubators is possible by bedside measurement of volatile organic compounds (VOCs) on the neonatal intensive care unit. VOC profiles were measured in the incubator air using ion mobility spectrometry coupled to multi-capillary columns (BreathDiscovery B&S Analytik GmbH, Dortmund, Germany). Results: Seventeen incubators occupied by preterm infants (50 measurements) and nine unoccupied neonatal incubators were sampled, using 37 room air measurements as controls. Three VOC signals that allow the discrimination between occupied and unoccupied incubators were identified. The best discrimination was reached by peak P20 exhibiting a sensitivity, specificity, positive predictive value and negative predictive value of 94.0, 88.9, 97.3, and 72.3%, respectively. Use of a decision tree improved these values to 100.0, 88.9, 98.0, and 100.0%, respectively. Discussion: A bedside method that allows the characterization of VOC profiles in the neonatal incubator atmosphere using ion mobility spectrometry was established. Occupied and unoccupied incubators could be discriminated by characterizing VOC profiles. This technique has the potential to yield results within minutes. Thus, future studies are recommended to test the hypothesis that VOCs within neonatal incubators are useful biomarkers for non-invasive diagnostics in preterm neonates

Patterns of volatile organic compounds in excrements of preterm neonates

Background: As neonates are susceptible for many diseases, establishing noninvasive diagnostic methods is desirable. We hypothesized that volatile organic compounds (VOCs) could be successfully measured in diaper samples. Methods: We performed a feasibility study to investigate whether ambient airindependent headspace measurements of the VOC profiles of diapers from premature infants can be conducted using ion mobility spectrometer coupled with multi-capillary columns (B & S Analytik GmbH). Results: We analysed 39 diapers filled with stool (n = 10) or urine (n = 20) respectively, using empty diapers as a control (n = 9). A total of 158 different VOCs were identified, and we classified the content of the diapers (urine or stool) according to their VOC profiles with a significance level of p<0.05. Conclusions: We have developed a novel method to study headspace VOC profiles of biosamples using ion mobility spectrometry coupled with multi-capillary columns. Using this method, we have characterized the VOC profiles of stool and urine of preterm neonates. Future studies are warranted to characterize specific VOC profiles in infections and other diseases of the preterm neonate, thus establishing quick and noninvasive diagnostics in the routine care of the highly vulnerable preterm and term neonates

Detection of volatile organic compounds in headspace of Klebsiella pneumoniae and Klebsiella oxytoca colonies

Introduction: Early diagnosis of infections and sepsis is essential as adequate therapy improves the outcome. Unfortunately, current diagnostics are invasive and time-consuming, making diagnosis difficult, especially in neonatology. Novel non-invasive analytical methods might be suitable to detect an infection at an early stage and might even allow identification of the pathogen. Our aim is to identify specific profiles of volatile organic compounds (VOCs) of bacterial species. Methods: Using multicapillary column-coupled ion mobility spectrometry (MCC/ IMS), we performed headspace measurements of bacterial cultures from skin and anal swabs of premature infants obtained during weekly screening for bacterial colonization according to KRINKO. We analyzed 25 Klebsiella pneumoniae (KP) cultures on MacConkey (MC) agar plates, 25 Klebsiella oxytoca (KO) cultures on MC agar and 25 bare MC agar plates as a control group. Results: Using MCC/IMS, we identified a total of 159 VOC peaks. 85 peaks allowed discriminating KP and bare MC agar plates, and 51 peaks comparing KO and bare MC agar plates and 6 peaks between KP and KO (significance level of p < 0.05 after Bonferroni post hoc analysis), respectively. Peaks P51 (n-Decane) and P158 (Phenylethyl Alcohol), showed the best sensitivity/specificity/ positive predictive value/negative predictive value of 99.9% each (p < 0.001) for KP. P158 showed the best sensitivity/specificity/positive predictive value/negative predictive value of 99.9% each (p < 0.001) for KO. Comparing KP and KO, best differentiation was enabled using peaks P72, P97 and P16 with sensitivity/specificity/positive predictive value/negative predictive value of 76.0%, 84.0%, 82.6%, 77.8%, respectively (p < 0.05)