- MeSH
- Elastic Modulus MeSH
- Flexural Strength MeSH
- Statistics as Topic MeSH
- Materials Testing methods instrumentation MeSH
- Dental Veneers * classification MeSH
- Dental Materials * analysis classification therapeutic use MeSH
- Dental Porcelain analysis classification therapeutic use MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
Measurement of thermal resistance of polymer sheets and fibrous layers is important in various applications including those within the engineering, ergonomics, clothing design and personal protective equipment fields. Standard methods for measurement of thermal resistance of plain materials are generally time consuming, expensive and often require the sample to be cut. Moreover, the temperature difference between the surfaces of both plates surrounding the sample must be known, as well as the sample thickness. This article describes a new measuring device named the Thermoscope. The Thermoscope is not limited by the aforementioned requirements and is able to evaluate the thermal resistance of polymer sheets and textiles by touching the sample on one surface alone. Simultaneously, the other surface is kept in thermal contact with the supporting base. The accuracy of this device was compared with the Alambeta thermal insulation tester. Effects of various base materials on measurement precision were also studied.
- MeSH
- Polymers MeSH
- Thermal Conductivity MeSH
- Materials Testing instrumentation methods MeSH
- Textiles MeSH
- Publication type
- Journal Article MeSH
This work deals with non-destructive testing of artificial joints made from the austenitic steel SUS316L based on eddy current method. The technique is appropriate for final investigation of artificial joints before insertion the prosthesis into human body to avoid repeated operations. The most commonly implanted joints - knee and hip joint are evaluated in this study. The eddy current probe consists of one coil, which has both the excitation and sensing functions. Five detects are inspected using three different frequencies. The numerical simulations from Opera software with experiments are compared in this article to obtain the most appropriate frequency. The aim of this work is evaluation which frequency provides the biggest magnitude difference between individual simulated signals with various depths if surface defects are inspected.
- Keywords
- testování umělých kloubů, vířivé proudy, austenitická ocel,
- MeSH
- Hip Prosthesis * standards MeSH
- Humans MeSH
- Joint Prosthesis standards MeSH
- Knee Prosthesis * standards MeSH
- Chromium Alloys standards MeSH
- Materials Testing * methods standards instrumentation statistics & numerical data MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Experimental modal analysis (EMA) of ultrasonic waveguides is important for many applications including design of ultrasonic surgical tools. However, most of the known sensors and instruments for measuring parameters of ultrasonic vibrations are limited to the measurements on the face surface of the ultrasonic waveguide and therefore unable to determine the spatial distribution of the parameters along its length, which in turn makes it difficult to identify natural modes and shapes. The article describes EMA of ultrasonic surgical waveguides based on the effect of inverse magnetostriction. During vibration of an ultrasonic waveguide the inverse magnetostriction generates alternating magnetic field which can be detected by means of an induction coil. Spatial resolution of the measurements can be achieved by application of the sensors with flat (spiral) induction coils. The sensors used in the study have simple design and low cost making them affordable for wide circle of scientists and engineers. The results of experimental studies implemented on exemplary waveguide for ultrasonic angioplasty made of AISI 321 steel are presented and discussed. The article also discusses the methods for theoretical and experimental determination of the sensitivity of the sensors used in the study. Experimental data are validated by comparing them to the results of computer-aided modal analysis using the finite element method (FEM) and found to be in good agreement with the results of FEM modeling (relative deviation of the vibratory displacements amplitude is about 4.7 %). As it follows from the experimental data and their comparison to the results of FEM modeling, the effect of inverse magnetostriction can be efficiently used for EMA of ultrasonic waveguides.
With growing interest in monitoring the health status of a human has raised demands on measuring systems and devices. It is important to develop monitoring system with user friendly and comfortable interface. This applies not only to setup and control but also to wearing and manipulation. Therefore, the replacement of conventional metal, rubber and selfadhesive electrodes by electrodes with thin-film conductive layer is desirable. These electrodes combine good electrical properties altogether with comfortable wearability, ease of manipulation and low-cost fabrication. The indicated factors allow these electrodes to be used in commercial measuring systems and devices. Their applicability in long term measurements is subject to meeting additional requirements, such as chemical and mechanical resistance. Abrasion caused by rubbing the human skin during standard measurements might affect the functionality of the electrode. Four types of electrodes based on Au, ITO, Graphite filled polymer and PEDOT:PSS underwent series of testing of their abrasion resistance. A surface with specific roughness and pressure force was used. A change in amplitude of testing ECG signal was measured as a function of number of abrasion cycles for all electrodes.
In the current study, well-defined polymer brushes are shown as an effective surface modification to resist the adhesion of whole blood and its components. Poly[oligo(ethylene glycol)methylether methacrylate] (poly(MeOEGMA)), poly(hydroxyethyl methacrylate) (poly(HEMA)), poly[N-(2-hydroxypropyl) methacrylamide] (poly(HPMA)), and poly(carboxybetaine acrylamide) (poly(CBAA)) brushes were grown by surface initiated atom transfer radical polymerization (SI-ATRP) and subsequently characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), dynamic contact angle measurements, atomic force microscopy (AFM), and surface plasmon resonance (SPR) spectroscopy. All brushes decreased the fouling from blood plasma over 95% and prevented the adhesion of platelets, erythrocytes, and leukocytes as evidenced by SPR and SEM measurements.
- MeSH
- Coated Materials, Biocompatible chemistry MeSH
- Biofouling MeSH
- Cell Adhesion MeSH
- Photoelectron Spectroscopy MeSH
- Blood metabolism MeSH
- Humans MeSH
- Microscopy, Atomic Force MeSH
- Platelet-Rich Plasma MeSH
- Polymerization MeSH
- Polymers chemical synthesis chemistry MeSH
- Surface Properties MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Materials Testing instrumentation MeSH
- Water MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Omezené množství nasaditelných sil složených z vysoce specializovaných jednotek a útvarů Chemického vojska Armády České republiky může působit limitně při plnění operačních úkolů souvisejících s odstraňováním následků po použití zbraní hromadného ničení či po únicích průmyslových nebezpečných látek. Článek poukazuje na některé aspekty možného využití metody QCM detekce při stanovování koncentrací proniklých toxických látek na základě průběhu permeačních křivek a po provedené kalibraci zařízení. Ukázané přístupy mohou být uplatněny nejenom ve vztahu ochrany specialistů CHV AČR ve vojenských operacích, ale následně také ve vztahu k ochraně personálu pracujícího v prostředí, kde se toxické látky vyskytují.
The restricted amount of deployable forces composed of highly specialized units of the Czech Armed Forces Chemical Corps can be limiting within the fulfillment of operational tasks connected with problems concerning the liquidation of consequences of either the employment of Weapons of Mass Destruction or the leakage of Toxic Industrial Materials. The paper points to some aspects of the possible application of the QCM method in determining the concentration of toxic substances that have penetrated, based on the course of permeation curves and after calibration of the measuring equipment. The presented approaches can be applied not only regarding the protection of Czech Armed Forces Chemical Corps specialists but subsequently also as regards the protection of personnel working in environment in which toxic compounds occur.
- Keywords
- PIEZOTEST, vojenská toxikologie,
- MeSH
- Chemical Warfare Agents * analysis adverse effects toxicity MeSH
- Calibration MeSH
- Quartz Crystal Microbalance Techniques methods instrumentation MeSH
- Hazardous Substances analysis adverse effects toxicity MeSH
- Protective Clothing * standards MeSH
- Permeability MeSH
- Occupational Exposure analysis adverse effects MeSH
- Materials Testing * methods standards instrumentation MeSH
- Toxicology MeSH
- MeSH
- Financing, Organized MeSH
- Metal Nanoparticles diagnostic use MeSH
- Rats MeSH
- Magnetics instrumentation MeSH
- Rats, Wistar MeSH
- Materials Testing methods instrumentation MeSH
- Tissue Distribution MeSH
- Ferric Compounds administration & dosage pharmacokinetics MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
Úvod a cíl práce: Mezi největší výhody keramických materiálů patří i jejich všeobecně uznávaná biologická netečnost. Cílem práce bylo hodnocení koroze polykrystalického sklem infiltrovaného materiálu In-Ceram Spinell (Vita, SRN) v běžně dostupných nápojích a roztocích in vitro. Materiál: Keramický materiál In-Ceram Spinell (Vita, SRN) byl podroben imerznímu testu, kdy byla použita následující vyluhovací média: Ice Tea Peach (Lidl Stiftung & Co. KG, DEU; pH 2,99), Freeway Cola (Lidl Stiftung & Co. KG, DEU; pH 2,42), červené víno Cabernet Sauvignon (Vinné sklepy Peter Metres KG; pH 3,59), bílé víno (Izrael; pH 3,23), džus 100% pomeranč (Relax Ltd., NZL; pH 3,76), ústní voda Colgate Plax Whitening (Colgate – Palmolive, SUI; pH 8,04), 0,9% NaCl (pH 5,35), 0,5% kyselina octová (pH 2,56), 2% kyselina citronová (pH 1,98), 0,1M HCl (pH 1,54), redestilovaná voda (pH 5,70). Vzorky uvedeného materiálu byly vyluhovány při 37 °C po dobu 7 dní. U vzorků byl hodnocen jejich hmotnostní úbytek a dále byly sledovány změny jejich barvy. Uvedená vyluhovací média byla po imerzním testu podrobena prvkové analýze pomocí optické emisní spektrometrie s indukčně vázaným plazmatem (ICP OES), kdy byl sledován nárůst koncentrací vybraných prvků. Výsledky: Největší hmotnostní úbytek byl zjištěn u vzorků testovaných v kyselině citronové. Z výsledků je patrné, že s klesajícím pH roste úbytek hmotnosti. Změna barvy byla zaznamenána u vzorků testovaných ve Freeway cole a v červeném víně, které byly pokryté různě barevnou usazeninou. Analýza pomocí ICP OES prokázala nárůst koncentrací vápníku, hořčíku, hliníku, yttria, křemíku a dalších prvků ve výluzích. Závěr: Ač bývá dentální keramika označována jako chemicky inertní materiál, při testování keramického materiálu In-Ceram Spinell, kdy jako korozní činidla sloužily vybrané nápoje a roztoky, bylo prokázáno, že tomu tak není. Klíčová slova: prvková analýza – optická emisní spektrometrie – dentální keramický materiál – In-Ceram Spinell – imerzní test – koroze
Introduction: The biocompatibility of ceramic materials belongs to the best benefits of these dental materials. Aim: Paper presents in vitro corrosive behaviour testing procedure of ceramic dental material in preselected beverages and solutions. Methods: The ceramic material In-Ceram Spinell (Vita, Germany) was immersed using following leaching agents: Ice Tea Peach (Lidl Stiftung & Co. KG, DEU; pH 2.99), Freeway Cola (Lidl Stiftung & KG, DEU; pH 2.42), red wine Cabernet Sauvignon (Wine Cellars Peter Metres KG; pH 3.59), white wine (Israel; pH 3.23), juice 100% orange (Relax Ltd., NZL; pH 3.76), mouth wash Colgate Plax Whitening (Colgate – Palmolive, SUI; pH 8.04), 0.9% NaCl (pH 5.35), 0.5% acetic acid (pH 2.56), 2% citric acid (pH 1.98), 0,1M HCl (pH 1.54), redistilled water (pH 5.70). Samples of the mentioned material were immersed at 37 °C during seven days. The change of sample masses and the change of colour was followed. After immersion test, leaching agents used we analysed using inductively coupled plasma optical emission spectrometry (ICP OES) and the increase in concentration of chosen elements was monitored. Results: The highest loss up of sample masses was found for samples tested in citric acid. The loss of material mass is related to pH. The colour change was monitored in samples treated in Freeway Cola and red wine, they came under different colour changes. ICP OES analysis demostrated the increase in concentration of calcium, magnesium, aluminium, yttrium, silica and other elements in extracts. Conclusion: Though the dental ceramics is considered to be bioinert, the corrosive behaviour of In-Ceram Spinell was monitored in the presence of currently used beverages and solutions. Key words: elementary analysis – optical emission spektrometry – dental ceramics – In-Ceram Spinell – immersion test – corrosion
- Keywords
- prvková analýza, optická emisní spektrometrie s indukčně vázaným plazmatem, imerzní test, In-Ceram Spinell, ICP OES,
- MeSH
- Biocompatible Materials MeSH
- Chemistry Techniques, Analytical MeSH
- Mass Spectrometry methods instrumentation statistics & numerical data MeSH
- Ceramics * chemistry adverse effects MeSH
- Hydrogen-Ion Concentration MeSH
- Corrosion * MeSH
- Citric Acid MeSH
- Acetic Acid MeSH
- Beverages * analysis MeSH
- Immersion MeSH
- Surface Properties MeSH
- Elements MeSH
- Solutions chemistry MeSH
- In Vitro Techniques MeSH
- Materials Testing methods instrumentation statistics & numerical data MeSH
- Mouthwashes MeSH
- Wine MeSH
- Water MeSH
- Dental Porcelain chemistry adverse effects MeSH
- Publication type
- Evaluation Study MeSH
- Research Support, Non-U.S. Gov't MeSH
