Toplinski modificirano drvo za izradu glazbenih instrumenata

The unique mechanical and acoustical properties of wood and its aesthetic appeal still make it the material of choice for musical instruments. Here tropical hardwoods are typically used in musical instruments. This paper gives an overview of how the use of thermally modified wood can contribute to the use of raw materials for musical instruments. It is shown that a mild thermal treatment leads to clear changes of the measurable acoustic characteristics, such as Young’s modulus, damping and sound velocity. In conclusion, thermally modified wood (mild treatment) is a material with favorable characteristics for making musical instruments.Zbog jedinstvenih mehaničkih i akustičnih svojstava te estetskih obilježja drvo se često rabi kao materijal za izradu glazbenih instrumenata. U radu se opisuje kako uporaba toplinski modificiranog drva može pridonijeti boljoj raspoloživosti sirovine za izradu glazbenih instrumenata. Pokazalo se da blaga toplinska obrada drva dovodi do jasnih promjena mjerljivih akustičnih veličina kao što su Yangov modul elastičnosti, prigušenje i brzina zvuka. Zaključno, drvo koje je umjereno toplinski modificirano ima poželjna obilježja za izradu glazbenih instrumenata

Standards-Based Regulation of Athletic Protective Headgear - Policy Background, Mechanisms and Evaluation

This paper considers the regulatory reality of sports equipment that is at the center of this brain trauma in sports issue. It reveals that not all regulation concerning athletic head injuries occurs in the public sector. It goes on to explain that in the case of sports helmets, very little is performed by the government and explains how the private sector executes this regulation instead. Protective equipment (helmets, by and large) are regulated, or more precisely, quasi-regulated by a structure defined largely by private technical standards. This paper offers an introduction to these standards and explains the key elements and differences between the private regulatory models for helmets. It also evaluates the effectiveness of standards-based regulation of athletic headgear and concludes with recommendations for adjustments to the existing conformity assessment systems and undertakings by the helmet standards community that would serve the end of providing excellent private regulation for equipment that faces the serious challenge of reducing brain injury in sports

Neues Konzept für ein modulares Robotersystem zur automatischen Untersuchung von Zebrabärblingen in Hochdurchsatzverfahren

Es wird ein neues Konzept für die automatische Durchführung von Hochdurchsatzuntersuchungen mit Zebrabärblingen beschrieben. Kern des Konzepts ist ein modularer Grundroboter, der durch Funktionsmodule für die Bearbeitung verschiedener biologischer Fragestellung ergänzt wird. Mit den entwickelten Robotern werden bisher manuell erledigte Handhabungs- und Bildakquiseschritte automatisiert. Ein spezielles Transportsystem verbindet die Einzelroboter zu einer automatischen Gesamtprozesskette

Promjena koeficijenta upijanja vode smrekovine (Picea abies (L.) Karst.) zbog njezine termičke modifikacije

The aim of the investigations was to evaluate the infl uence of a thermal modifi cation on the water absorption behaviour of spruce (Picea abies(L.) Karst.). After recording the water uptake of wood samples by partial immersion, a water absorption coefficient of the material could be determined according to EN ISO 15148:2002. The thermal modification results in an alteration of the water absorption behaviour in dependence on the sectional area. In radial and tangential direction the water absorption decreases with the modification. In contrast, in longitudinal direction the water uptake increases.Cilj istraživanja bio je procijeniti utjecaj termičke modifikacije smrekovine (Picea abies (L.) Karst.) na svojstvo upijanja vode. Bilježenjem količine vode što ju upiju drvni uzorci nakon njihova djelomičnog uranjanja može se, prema normi EN ISO 15148:2002, odrediti koeficijent upijanja vode. Termičkom modifikacijom drva mijenja se svojstvo upijanja vode u ovisnosti o površini presjeka drva. U radijalnome i tangencijalnom smjeru upijanje vode se smanjuje u modificiranog drva. Suprotno tomu, u uzdužnom se smjeru upijanje vode povećava

Wertschöpfung: Eine kulturelle Kehre

Zum sechsten Male fanden in diesem November die Spiekerooger Klimagespräche statt. In einem ungewöhnlichen Veranstaltungsformat tauschen sich Wissenschaftler(innen) und andere Menschen darüber aus, wie die Gesellschaft die mit dem Klimawandel zusammenhängenden Herausforderungen bewältigen kann

Theorie als Notverordnung

Benötigt die Betriebswirtschaftslehre eine neue Theorie der Unternehmung zur Fundierung von Umweltmanagementsystemen? Diese Frage ist wiederholt Gegenstand der Diskussion. Mit folgendem Beitrag soll deshalb eine lockere Folge von Beiträgen im Informationsdienst eingeleitet werden, die verschiede-ne Theorieangebote für die Bearbeitung von Fragen der ökologischen Unterneh mensführung auf ihre Brauchbarkeit und Reichweite abklopfen

Armirani beton s mineraliziranim česticama drva kao element za ukrućenje smanjene gustoće

The aim of the cooperative research project was the development of a wood-cement in-situ concrete used as local fi ller and stiffening element in wooden ceiling elements. For further processing, only water should be added to the mineralized particles, whereby the amount of added water is relevant to the adjustment of the consistence and flowing characteristics. Portland cement was used as binding component. Particle residues of Scots Pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.) from sanding with 60 grit paper, as filling components, were supplied by Lignotrend GmbH, an industrial manufacturer of solid wood structural elements (cross laminated timber) and project partner. The mineralization of these wood particles has also been studied. Three different ways to accelerate the hydration of the cement and therefore to counteract the effect of the so called cement poisons were examined. Moreover, the compressive strength of hardened concrete had to be set to not less than 3.2 N/mm2, which was also examined.Cilj zajedničkog istraživanja bio je proizvesti beton od drva i cementa koji će se upotrebljavati kao punilo i kao element za ukrućivanje drvnih stropnih elemenata. Za daljnju obradu mineraliziranim česticama drva treba samo dodati vodu, pri čemu je količina dodane vode relevantna za prilagodbu konzistencije i svojstva tečljivosti betona. Kao vezivna komponenta upotrijebljen je portlandski cement, a kao punilo drvne čestice nastale brušenjem drva običnog bora (Pinus sylvestris L.) i smreke (Picea abies (L.) Karst.), i to brusnim papirom granulacije 60. Drvne čestice dobavljene su od tvrtke Lignotrend GmbH, industrijskog proizvođača strukturnih elemenata od masivnog drva (unakrsnoga lameliranog drva), koja je ujedno i partner u projektu. Mineralizacija čestica drva također je dio istraživanja. Istražena su tri različita načina ubrzavanja hidratacije cementa, a istraženi su i tim procesima suprotni učinci, tzv. otrovi cementa, kao i tlačna čvrstoća otvrdnutog betona, koja ne smije biti manja od 3,2 N / mm2