THERMAL INSULATION EFFECTS ON ENERGY EFFICIENCY OF BUILDING STRUCTURES

This paper presents the use of Finite Element Method for heat transfer analysis. Connections wall-beam-floor structures with different positions of the thermal insulation have been analyzed and conclusions about energy efficiency and energy loss are made. Keywords: heat transfer, numerical analysis, finite elements, thermal insulation, energy efficiency

PLASTIC ANALYSIS OF STEEL FRAME STRUCTURE

This paper presents the plastic analysis of steel frame structure loaded by gravity loads. By applying the cinematic theorem of ultimate analysis, the ultimate load for the case of elastic - ideally plastic material is calculated. The identical structure was treated in the computer program SAP2000 where the zone of material reinforcement in the plastic area was covered. Keywords: Steel frame structure, plastic analysis, ultimate gravity load, material reinforcement

THE INFLUENCE OF POLYACRYLAMIDE (PAA) ON HYDROGEN EVOLUTION REACTION AT THE POLYCRYSTALLINE GOLD

The influence of polyacrylamide (PAA; Mn between 5∙103 and 1.5∙106 gmol-1 ) on hydrogen evolution reaction at the polycrystalline gold in 0.5 M H2SO4 was studied using potentiodynamic measurements (5 mV/s) in the potential range from 0 to -0.6 V/she. It was concluded that formation of protective layer of PAA, adsorbed on the electrode surface, is responsible for inhibition of hydrogen evolution reaction. The further investigations, especially on iron and steel in acid solutions (real corrosion system) confirm the effective inhibition of corrosion by PAA

Biocompatible Polymer Blends of Poly(D,L-lactic acid-co-glycolic acid) and Triblock PCL-PDMS-PCL Copolymers: Their Characterizations and Degradations

Polymer blends of poly(D,L-lactic-co-glycolic acid), PDLLGA, and triblock polycaprolactonepoly(dimethylsiloxane)-polycaprolactone (PCL-PDMS-PCL) copolymer, TEGOMER, were obtained by coprecipitation from their chloroform mixed solutions into methanol and were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), degradation tests and scanning electron microscopy (SEM). Binary blends of PDLLGA/TEGOMER were found to be partially miscible according to DSC measurements and FTIR analysis. Stressstrain results showed that addition of TEGOMER improved significantly the overall toughness of PDLLGA. Degradation of PDLLGA/TEGOMER blends was investigated in phosphate buffered saline at pH = 7.4 and 37 °C, and the morphology of the blends during degradation was examined by scanning electron microscopy

Biocompatible Polymer Blends of Poly(D,L-lactic acid-co-glycolic acid) and Triblock PCL-PDMS-PCL Copolymers: Their Characterizations and Degradations

Polymer blends of poly(D,L-lactic-co-glycolic acid), PDLLGA, and triblock polycaprolactonepoly(dimethylsiloxane)-polycaprolactone (PCL-PDMS-PCL) copolymer, TEGOMER, were obtained by coprecipitation from their chloroform mixed solutions into methanol and were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), degradation tests and scanning electron microscopy (SEM). Binary blends of PDLLGA/TEGOMER were found to be partially miscible according to DSC measurements and FTIR analysis. Stressstrain results showed that addition of TEGOMER improved significantly the overall toughness of PDLLGA. Degradation of PDLLGA/TEGOMER blends was investigated in phosphate buffered saline at pH = 7.4 and 37 °C, and the morphology of the blends during degradation was examined by scanning electron microscopy

A genetic cause of Alzheimer disease: mechanistic insights from Down syndrome

Down syndrome, caused by an extra copy of chromosome 21, is associated with a greatly increased risk of early onset Alzheimer disease. It is thought that this risk is conferred by the presence of three copies of the gene encoding amyloid precursor protein (APP), an Alzheimer risk factor, although the possession of extra copies of other chromosome 21 genes may also play a role. Further study of the mechanisms underlying the development of Alzheimer disease in Down syndrome could provide insights into the mechanisms that cause dementia in the general population

PET PACKAGING CHARACTERIZATION BY MEANS OF DIELECTRIC THERMAL ANALYSIS AND IMPEDANCE SPECTROSCOPY

Chemical inertness and physical properties like adequate gas barrier, transparency, light weight and good recyclability, have made poly(ethylene therephtalate) (PET) particularly suitable in food packaging applications, especially in beverages and drinking water. However, several studies have shown the presence of compounds not expected a priori in packed food or bottled water and other beverages. One of the possible sources of these substances is a migration of constituents like monomers, catalysts, additives, degradation products, impurities in starting substances etc, from PET packaging. Therefore, migration of possible contaminants from PET, in normal and extreme conditions, is extensively studied and huge amount of data are reported elsewhere. As the migration process from plastics is closely related to the structure and physical properties of the packaging material, the aim of this work was to study structural changes of PET packaging in different media and under different conditions, and to correlate the data with the possibilities for migration of possible contaminants into the food in contact. It was shown that both techniques, especially DETA, could indicate structural changes into the polymer material, under certain conditions related with packaging applications, which could promote migration process

Impedance characteristics of conducting polypyrrole-poly(ethylvinylether) graft films

Impedance characterization of graft copolymers of poly(2-(N-pyrrolyl)ethylvinylether) and polypyrrole (doped with BF4-) was elucidated in comparison with pure polypyrrole doped with BF4-