Průtoková analýza 3/2 směrového pneumatického ventilu, pomocí softwaru Ansys CFX

The main purpose of this paper was to develop a selection method of the pneumatic connectors for directional 3/2 valve. The method was established to minimize resistance and loss of pressure in the valve with mounted pneumatic connections for the selected pipe diameters. Directional valve was modeled in 3D CAD software SolidWorks while 3D models of the air connections have been downloaded from the website of one of the leading suppliers of pneumatic. Based on developed solid model the simulation of compressed air flow in the software for computational fluid dynamics Ansys CFX was conducted. The studies using CFD methods helped to determine which air connections best meet the assumptions. Performed numerical tests enable proper selection of items to the newly designed pneumatic systems for a particular group of valves. As a consequence, this translates into a reduction in energy consumption and improve the efficiency of the entire pneumatic complex system.Článek popisuje metodu pro vyhodnocení tlakových ztrát u 3/2 směrového pneumatického ventilu s pneumatickými spojkami pro vybrané průměry rozvodů tlakového vzduchu. 3D model ventilu byl vytvořen v CAD systému SolidWorks a modely pneumatických spojek byly staženy z webu významného dodavatele pneumatických komponent. Na těchto 3D modelech pak byla provedena průtoková simulace stlačeného vzduchu s využitím simulačního systému dynamiky tekutin Ansys CFX. Využití CFD metod umožňuje stanovit, které pneumatické zapojení ventilu nejlépe splňuje stanovené předpoklady. Provedené numerické výpočty umožňují volbu vhodných prvků při návrhu nové pneumatické ventilové sestavy. Dále pak vedou ke snížení spotřeby energie a zvýšení efektivity celého pneumatického systému

Aplikace pneumatických svalů pro pneumatický delta manipulátor

The main aim of this study was to use pneumatic muscle actuators in the construction of the delta manipulator with a closed kinematic chain. The paper presents a solid models of the manipulator and the kinematic diagram. Based on the kinematic diagram and using DH notation (Denavit-Hartenberg) manipulator kinematic models was determined. On the basis of developed solid model simulation studies were conducted and the shape and size of the workspace determined. On the basis of 3D models prototype of the manipulator was constructed. Experimental studies were performed to select the regulators settings P, PI, PID for one of the pair of BMDS (Bi-Muscular Driving System) muscle-type drives. Based on integral quality indicators the used types of regulators were compared and proposed final controller. Performed experimental studies confirm the possibility of muscle control in the BMDS (Bi-Muscular Driving System) type system drives and tuning controller settings using the Ziegler-Nichols method.Hlavním cílem této studie bylo použití pneumatických svalových aktuátorů při konstrukci delta manipulátoru s uzavřeným kinematickým řetězcem. Příspěvek prezentuje solidní modely manipulátoru a kinematické schéma. Na základě kinematického schématu a použití DH (Denavitova-Hartenberg) notace byl stanoven kinematický model manipulátoru. Konstrukce byla vytvořena na základě simulačního modelu a byl určen přesný tvar a velikost. Manipulátor byl zkonstruován na základě 3D modelu prototypu. Experimentální studie byla provedena pro volbu nastavení regulátorů P, PI, PID pro jeden z dvojice svalových BMDS pohonů. Výsledný regulátor byl navržen na základě porovnání integrálních ukazatelů kvality používaných typů regulátorů. Provedená experimentální studie potvrzuje, možnost ovládání svalů v systému BMDS (Bi-muskular Driving System) a doladění nastavení pomocí metody Ziegler-Nichols

Methodology of obtaining information about societal needs : the foundations and their empirical verification

PURPOSE: This study aimed to identify the concept of a ‘societal need’, indicate sources of information about societal needs, and conduct a critical analysis of the foundations of the methodology of obtaining information about societal needs and their operationalization (social services).DESIGN/METHODOLOGY/APPROACH: The article was written based on a critical analysis of the literature and practical verification of the methodology applied in obtaining information about societal needs used in diagnosing such conditions (from the perspective of local government).FINDINGS: Society’s needs are constantly evolving, increasing in volume, and changing their quality. The method applied in this study to obtain information about societal needs of the local community restricted the range of the survey respondents (reporting societal needsbeneficiaries of social services), which points to the problem of selecting the suitable means of communication with the stakeholders relevant in this process. A diagnosis of societal needs cannot be aspect-based. Its potential is determined by the comprehensiveness of information obtained from all the parties representing the stakeholders of the social policy system.PRACTICAL IMPLICATIONS: The possibilities of practical implementation aimed at identifying societal needs to create a comprehensive range of the offered social services provided by entities from various sectors of the economy and the modernization and maintenance of services in the system of social policy.ORIGINALITY/VALUE: A critical assessment of the applied methodology for obtaining information about the societal needs of a given community and the possibilities of resolving social problems thanks to the provided social services.peer-reviewe

Light-Induced Responses of Slow Oscillatory Neurons of the Rat Olivary Pretectal Nucleus

Background: The olivary pretectal nucleus (OPN) is a small midbrain structure responsible for pupil constriction in response to eye illumination. Previous electrophysiological studies have shown that OPN neurons code light intensity levels and therefore are called luminance detectors. Recently, we described an additional population of OPN neurons, characterized by a slow rhythmic pattern of action potentials in light-on conditions. Rhythmic patterns generated by these cells last for a period of approximately 2 minutes. Methodology: To answer whether oscillatory OPN cells are light responsive and whether oscillatory activity depends on retinal afferents, we performed in vivo electrophysiology experiments on urethane anaesthetized Wistar rats. Extracellular recordings were combined with changes in light conditions (light-dark-light transitions), brief light stimulations of the contralateral eye (diverse illuminances) or intraocular injections of tetrodotoxin (TTX). Conclusions: We found that oscillatory neurons were able to fire rhythmically in darkness and were responsive to eye illumination in a manner resembling that of luminance detectors. Their firing rate increased together with the strength of the light stimulation. In addition, during the train of light pulses, we observed two profiles of responses: oscillationpreserving and oscillation-disrupting, which occurred during low- and high-illuminance stimuli presentation respectively. Moreover, we have shown that contralateral retina inactivation eliminated oscillation and significantly reduced the firin

Noncovalent Interactions of Hydrated DNA and RNA Mapped by 2D-IR Spectroscopy

Biomolecules couple to their aqueous environment through a variety of noncovalent interactions. Local structures at the surface of DNA and RNA are frequently determined by hydrogen bonds with water molecules, complemented by non-specific electrostatic and many-body interactions. Structural fluctuations of the water shell result in fluctuating Coulomb forces on polar and/or ionic groups of the biomolecular structure and in a breaking and reformation of hydrogen bonds. Two-dimensional infrared (2D-IR) spectroscopy of vibrational modes of DNA and RNA gives insight into local hydration geometries, elementary molecular dynamics, and the mechanisms behind them. In this chapter, recent results from 2D-IR spectroscopy of native and artificial DNA and RNA are presented, together with theoretical calculations of molecular couplings and molecular dynamics simulations. Backbone vibrations of DNA and RNA are established as sensitive noninvasive probes of the complex behavior of hydrated helices. The results reveal the femtosecond fluctuation dynamics of the water shell, the short-range character of Coulomb interactions, and the strength and fluctuation amplitudes of interfacial electric fields.Comment: To appear as Chapter 8 of Springer Series in Optical Sciences: Coherent Multidimensional Spectroscopy -- Editors: Cho, Minhaeng (Ed.), 201

Vibrational Spectroscopic Map, Vibrational Spectroscopy, and Intermolecular Interaction

© 2020 American Chemical Society. Vibrational spectroscopy is an essential tool in chemical analyses, biological assays, and studies of functional materials. Over the past decade, various coherent nonlinear vibrational spectroscopic techniques have been developed and enabled researchers to study time-correlations of the fluctuating frequencies that are directly related to solute-solvent dynamics, dynamical changes in molecular conformations and local electrostatic environments, chemical and biochemical reactions, protein structural dynamics and functions, characteristic processes of functional materials, and so on. In order to gain incisive and quantitative information on the local electrostatic environment, molecular conformation, protein structure and interprotein contacts, ligand binding kinetics, and electric and optical properties of functional materials, a variety of vibrational probes have been developed and site-specifically incorporated into molecular, biological, and material systems for time-resolved vibrational spectroscopic investigation. However, still, an all-encompassing theory that describes the vibrational solvatochromism, electrochromism, and dynamic fluctuation of vibrational frequencies has not been completely established mainly due to the intrinsic complexity of intermolecular interactions in condensed phases. In particular, the amount of data obtained from the linear and nonlinear vibrational spectroscopic experiments has been rapidly increasing, but the lack of a quantitative method to interpret these measurements has been one major obstacle in broadening the applications of these methods. Among various theoretical models, one of the most successful approaches is a semiempirical model generally referred to as the vibrational spectroscopic map that is based on a rigorous theory of intermolecular interactions. Recently, genetic algorithm, neural network, and machine learning approaches have been applied to the development of vibrational solvatochromism theory. In this review, we provide comprehensive descriptions of the theoretical foundation and various examples showing its extraordinary successes in the interpretations of experimental observations. In addition, a brief introduction to a newly created repository Web site (http://frequencymap.org) for vibrational spectroscopic maps is presented. We anticipate that a combination of the vibrational frequency map approach and state-of-the-art multidimensional vibrational spectroscopy will be one of the most fruitful ways to study the structure and dynamics of chemical, biological, and functional molecular systems in the future

Expression of RUNX2 and its signaling partners TCF7, FGFR1/2 in cleidocranial dysplasia

RUNX2 is a member of the PEBP2/CBF transcription factors family controlling the expression of genes whose products are essential for bone formation. Mutations in the RUNX2 gene may be associated with cleidocranial dysplasia (CCD), a rare skeletal disease characterized by stature aberrations, delayed closure of the cranial sutures, hypoplastic or aplastic clavicles, and multiple dental abnormalities. As RUNX2 is involved in many signaling pathways, we hypothesize that CCD may be associated with their changes. We determined the expression of RUNX2 and its signaling partners TCF7, involved in canonical Wnt signaling, and fibroblast growth factor receptors, FGFR1 and FGFR2 in periodontum of CCD patients and control individuals. We did not observe any differences between the level of RUNX2, TCF7 and FGFR1/2 mRNA, determined by real-time PCR, in CDD patients and controls. Therefore, RUNX2 signaling pathways with their partners TCF7 and FGFR1/2 may not be involved in CCD pathogenesis

The use of biodegradable materials in dentistry : a review of the literature

W zależności od rodzaju utraconej struktury tkankowej w obrębie układu stomatognatycznego lub przerwania jej ciągłości mogą być wykorzystywane różne biomateriały, które powinny spełniać określone właściwości mechaniczne. Stosowane implanty, skafoldy, a także śruby, mikropłytki lub klamry zazwyczaj wykonane są z tytanu lub jego stopów. Postęp w dziedzinie biomateriałów spowodował, iż współcześnie wykorzystywane są również materiały biodegradowalne, które po spełnieniu swojej funkcji reparacyjnej ulegają samoistnej degradacji (tj. nici chirurgiczne). W pracy przeanalizowano piśmiennictwo dotyczące wykorzystania materiałów biodegradowalnych w stomatologii.Depending on the type of the lost tissue within the stomatognathic system or breaking of its continuity, various biomaterials having proper mechanical properties can be used. Applied implants, scafolds as well as screws, micro-plates or clamps are usually made of titanium or its alloys. Advances in the field of biomaterials caused that nowadays biodegradable materials are used, and after their reparative function become self-degrading (ie. surgical stitches). The paper analyzes the literature regarding the use of biodegradable materials in dentistry