Search results for " industry."
showing 10 items of 2285 documents
Excess enthalpies of solution of primary and secondary alcohols in dodecyldimethylamine oxide micellar solutions
1987
The excess enthalpies of solution with respect to water of some primary and secondary alcohols in dodecyldimethylamine oxide (DDAO) micellar solutions were measured by mixing aqueous solutions of alcohols with surfactant solutions. Standard free energies, enthalpies and entropies were obtained from the distribution of alcohols between aqueous and micellar phases. It is shown that thermodynamics of transfer of secondary alcohols from aqueous to the DDAO micellar phase differ slightly from those of their corresponding primary alcohols, that the additivity rule holds for free energies of transfer and that enthalpy and entropy display convex curves. The present data are compared with those from…
Multiarm star polyglycerol-block-poly(HEMA) as a versatile precursor for the preparation of micellar nanocapsules with different properties
2007
Well-defined multiarm star polymer with hyperbranched polyglycerol as core and poly(2-hydroxyethyl methacrylate) (PHEMA) as arms were used as precursor for the preparation of inverted and aqueous micellar nanocapsules. The partial modification of the hydroxyl groups of PHEMA arms with aliphatic chains led to the formation of inverted micellar nanocapsules. The hydrophilic dye encapsulation capacity of the inverted micelles can be enhanced significantly by transforming the inner hydroxyl groups of PHEMA arms into quaternized amine groups. The modification of the outer and inner hydroxyl groups of PHEMA arms with polyethylene glycol acid chloride and pivaloyl chloride, respectively, resulted …
Biosorption lead(II) and nikel(II) from an aqueous solution by bacterial biomass
2010
Biosorption lead(II) and nikel(II) from an aqueous solution by bacterial biomass The optimum conditions for biosorption of Pb(II) and Ni(II) from aqueous solution were investigated, by using living and nonliving Pseudomonas fluorescens and Bacillus pumilus isolated from wastewater treatment plant. It was found that the optimum pH for Pb(II) removal by living and nonliving cells was 6.0, while 7.0 for Ni(II) removal. At the optimal conditions, metal ion biosorption was increased as the initial metal concentration increased. The binding capacity by living cells is significantly higher than that of nonliving cells at tested conditions. The maximum biosorption capacities for lead and nickel by …
Halloysite Nanotubes Loaded with Calcium Hydroxide: Alkaline Fillers for the Deacidification of Waterlogged Archeological Woods
2018
A novel green protocol for the deacidifying consolidation of waterlogged archaeological woods through aqueous dispersions of polyethylene glycol (PEG) 1500 and halloysite nanotubes containing calcium hydroxide has been designed. First, we prepared functionalized halloysite nanotubes filled with Ca(OH)2 in their lumen. The controlled and sustained release of Ca(OH)2 from the halloysite lumen extended its neutralization action over time, allowing the development of a long-term deacidification of the wood samples. A preliminary thermomechanical characterization of clay/polymer nanocomposites allows us to determine the experimental conditions to maximize the consolidation efficiency of the wood…
Preservation of fungi in archaeological charcoal
2010
During the analysis of wood charcoal remains from archaeological sites, it is common to find different microorganisms and different forms of degradation present in the plant tissue. However, one may encounter difficulties when attempting to identify these microorganisms and determine when their attack occurred. This paper focuses on preservation aspects related to the microorganisms in wood and demonstrates the structural changes that take place in different types of decayed wood after it was converted into charcoal. The study seeks to determine whether the microbial attack found in archaeological woods took place before the burning of the wood or after. Burning experiments were conducted u…
Gone to smelt iron in Courland: technology transfer in the development of an early modern industry
2019
SUMMARY: In the Duchy of Courland and Semigallia, corresponding to the southern and western parts of present-day Latvia, an iron industry based on blast-furnace technology, mainly using local bog iron ore, existed in the 17th and 18th centuries. Transfer of knowledge and skill through the recruitment of specialists from other countries of Europe was crucial to the development of this industry; technology was also re-exported to Russia and elsewhere. Recent archaeological and archaeometallurgical investigations supplement the written evidence, highlighting the specific local conditions that influenced the development of ferrous metalworking here in the early modern period. This article will …
POROSITY DETERMINATION WITH HELIUM PYCNOMETRY AS A METHOD TO CHARACTERIZE WATERLOGGED WOODS AND THE EFFICACY OF THE CONSERVATION TREATMENTS
2012
The helium pycnometer allows us to measure the cell-wall density of dry woods and the basic density of wood samples soaked with water and/or a consolidant solution if a non-volatile solvent is used. These parameters were correlated to the porosity, which for degraded waterlogged wood is related to the maximum water content. Moreover, this has revealed the possibility of investigating, by means of accurate cell-wall density determination, the efficacy of several consolidants in the treatment of waterlogged woods.
Padure (Beltes) piliakalnio (Latvija) osteologinė medžiaga: rūšių pasiskirstymas ir skerdimo technologija
2013
In the excavated Padure (Beltes) hill-fort in Latvia, cultural layers from the Late Bronze Age and the Early Iron Age (Stage 1), and the Middle Iron Age and the Late Iron Age (Stage 2), were detected, which, besides the archaeological material typical of that period, provided abundant zooarchaeological material. This article presents the investigation data from the zooarchaeological material of both stages: the data relate to the butchering techniques used, and the identification of the composition of the faunal species. The investigation was carried out in the bioarchaeological laboratory of the Institute of Baltic Region History and Archaeology at Klaipėda University. As is proven by the …
La Cova de l’Hort de Cortés-Volcán del Faro (Cullera, Ribera Baixa, País Valenciano). Datos para la discusión de las ocupaciones presolutrenses
2020
Los resultados de las excavaciones realizadas entre 1968 y 1984 en la Cova de Hort de Cortés- Volcán del Faro quedaron limitados a identificar materiales solutrenses, magdalenienses y neolíticos-calcolíticos. Una lectura crítica de la Memoria de excavaciones, publicada en 2003, permitió plantear la posibilidad de la presencia de ocupaciones anteriores, posiblemente gravetienses. En 2018 se iniciaron nuevos trabajos en el yacimiento, dentro de un proyecto que pretende recuperar información a partir de los cortes de las antiguas excavaciones. Los datos obtenidos en el área más externa (corte frontal posterior, cuadrícula O4) han permitido retomar la discusión sobre la existencia de los nivele…
The Museum of Engines and Mechanisms. More Than a Century of History of Technology
2015
The Museum of Engines and Mechanisms of the University of Palermo has preserved more than 300 pieces, which collectively narrate the evolution of science and technology in the field of fluid machines and their components and testify to the development in scientific disciplines, technologies and industrial applications over the course of more than a century. A rigorous chronological path through the various typological groups allows for a historical walk through the last 150 years, in the area of automotive, airplanes and marine engines; hydraulic machines and stationary engines; mechanical measurements and laboratory devices for scientific and educational purposes. The collection is availab…