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1.
Blends of polyamide 6 (PA6) and polycarbonate (PC) have been investigated, over a full range of composition, to check interactions between them. SEM observations show that the mixtures are characterized by domains of clearly segregated homophases and voids between the two polymers. DSC and DMTA data indicate the presence of two Tg' s, corresponding to two separate phases, with the Tg of the PC phase decreasing on increasing the PA6 amount. Moreover, the crystallization kinetics of PA6 is slightly showed down by the PC. Chemical reactions between the two polymers are supposed to give rise to low molar mass compounds, as shown by GPC; these species plasticize the PC and partially dissolve into the molten polyamide, causing decrease of PC Tg and reduction of overall crystallization rate of PA6. Apparent influence of PC on melting temperature and enthalpy of PA6 is also discussed. 相似文献
2.
AbstractA latent heat thermal energy storage system with phase change material (PCM) is numerically studied. To enhance the heat transfer inside the system, a highly conductive metal foam is employed with ceramic nanoparticles. The latter method of enhancement leads to a new class of material called Nano-PCM. The system under investigation is a 70-L tank filled up with pure PCM or Nano-PCM and several pipes are situated where the heat transfer fluid (HTF) flows. The pipe surfaces are assumed at constant temperature above the PCM melting temperature to simulate the heat transfer from the HTF. The enthalpy-porosity theory is applied to simulate the PCM phase change, while the porous media formulation is assumed to describe the metal foam behavior. The nano-PCM is modeled with single-phase model where the properties are the weighted-average between the fluid base and the nanoparticles. The simulations are accomplished for charging-discharging process at different porosities and nanoparticle concentration. The results are given in term of average melting fraction evolution, average temperature as function of time, average stored energy. The metal foam significantly improves the heat transfer between PCM and HTF respect to the addition of nanoparticles, reducing the charging and discharging time more than one order of magnitude. 相似文献
3.
Kai-Ming Li N. V. S. Ramakrishna N. S. Padmavathi Eleanor G. Rogan Ercole L. Cavalieri 《Polycyclic Aromatic Compounds》2013,33(1-4):207-213
Abstract (±)?Syn?dibenzo[a,l]pyrene diol epoxide (DB[a,l]PDE) and (±)?anti?DB[a,l]PDE were reacted with deoxyadenosine (dA) or deoxyguanosine (dG) in dimethylformamide at 100 °C for 30 min. The crude products were purified by reverse phase HPLC under gradient and isocratic conditions. The structure of each adduct was assigned by 1D and 2D NMR spectra and by fast atom bombardment mass spectrometry. Five adducts were isolated from the reaction of (±)?syn?DB[a,l]PDE and dA: syn?DB[a,l]PDE?N6dA?1, syn?DB[a,l]PDE?N6dA?2, syn?DB[a,l]PDE?N6dA?3, syn?DB[a,l]PDE?N6dA?4 and syn?DB[a,l]PDE?N7Ade. Four adducts were isolated from the reaction of (±)?anti?DB[a,l]PDE and dA: anti?DB[a,l]PDE?N6dA?1, anti?DB[a,l]PDE?N6dA?2, anti?DB[a,l]PDE?N6dA?3 and anti?DB[a,l]PDE?N6dA?4. Two adducts were isolated from the reaction of (±)?syn?DB[a,l]PDE and dG: (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N2dG and (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N7Gua. Two adducts were isolated from the reaction of (±)?anti?DB[a,l]PDE and dG: (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N2dG and (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N7Gua. 相似文献
4.
The profiles of DNA adducts determined for benzo[a]pyrene (BP), 7,12-dimethylbenz[a]anthracene (DMBA) and dibenzo[a,l]pyrene (DB[a,l]P) reveal that a majority of adducts are released from DNA by depurination. Papillomas were induced in mouse skin by several PAH, and mutations in the c-Harvey-ras oncogene were determined to investigate the relationship between DNA adducts and ras oncogene mutations. The pattern of mutations induced by each PAH correlated with the profile of depurinating adducts. DB[a,l]P and DMBA formed predominantly depurinating adenine adducts (78% and 79%, respectively) and consistently induced a CAA → CTA transversion in codon 61 of ras. In contrast, BP produced both guanine (46%) and adenine (25%) depurinating adducts and induced a GGC → GTC mutation in codon 13 of c-H-ras in 54% of tumors and a CAA → CTA mutation in codon 61 in 15% of tumors. These results support the hypothesis that mis-replication of unrepaired apurinic sites generated by loss of PAH-DNA adducts is responsible for transforming mutations leading to papillomas in mouse skin. 相似文献
5.
Ercole L. Cavalieri 《Polycyclic Aromatic Compounds》2013,33(1-4):223-228
Abstract A major carcinogenic risk for many human cancers may be associated with endogenous procarcinogens that are precursors to carcinogens. If natural protective mechanisms become insufficient, these procarcinogens can be activated, giving rise to formation of endogenous carcinogens. Catechol estrogens (CE), which are metabolites of the estrogens estrone and 17β-estradiol are hypothesized to be such ubiquitous procarcinogens. Their oxidation to CE semiquinones and/or quinones can generate the DNA damage that leads to the tumor initiation process. In addition, redox cycling of CE semiquinones and quinones can generate free radicals that lead to enhancement of DNA damage. The minisymposium discussing this area of research was moderated by Pentti Siiteri and introduced by Ercole Cavalieri. It included presentations by Joachin Liehr, Judith Weisz, Cyrus Creveling and Herman Adlercreutz. 相似文献
6.
van der Schaar Mihaela Alaa Ahmed M. Floto Andres Gimson Alexander Scholtes Stefan Wood Angela McKinney Eoin Jarrett Daniel Lio Pietro Ercole Ari 《Machine Learning》2021,110(1):1-14
Machine Learning - The COVID-19 global pandemic is a threat not only to the health of millions of individuals, but also to the stability of infrastructure and economies around the world. The... 相似文献
7.
Enrico Bernardo Giovanni Scarinci Paolo Bertuzzi Piero Ercole Ludovico Ramon 《Journal of Porous Materials》2010,17(3):359-365
Waste soda-lime glass, alone or mixed with wastes from the manufacturing of glass fibers, was successfully converted into
partially crystallized glass foams by a particularly simple and economic processing, consisting of a direct heating of glass
powders at temperatures from 900 to 1050 °C. The foaming operated by the oxidation of SiC, inserted as powder additive, was
found to depend on a complex combination of processing temperature, soaking time, tendency of the investigated glasses toward
devitrification, and amount of MnO2, acting as oxidation promoter. Selected combinations led to foams with a good microstructural homogeneity and mechanical
strength, suitable for application as aggregates in lightweight concrete. 相似文献
8.
George Casale Eleanor Rogan Douglas Stack Prabu Devanesan Ercole Cavalieri 《Polycyclic Aromatic Compounds》2013,33(1-4):195-201
Molecular dosimetry of depurinating DNA adducts of benzo[a]pyrene (BP) offers a promising new approach to determining risk of PAH-induced cancer. Depurinating adducts are the predominant form of BP-induced DNA damage, are excreted in urine and, importantly, are linked to cancer initiation. We have produced a monoclonal antibody (MAb) with high specific affinity for BP-6-N7Gua, a major depurinating DNA adduct of BP, and have developed a sensitive and specific competitive enzyme-linked immunosorbent assay (ELISA). The I50S (quantity producing 50% inhibition of MAb binding in the ELISA) of selected BP adducts and metabolites were determined. The results indicated 1) a high degree of discrimination between BP-6-N7Gua (I50=750 fmol) and BP (I50=900,000 fmol), 2) high affinity of the MAb for BP-6-N7Ade (I50=1,500 fmol), another major depurinating DNA adduct, and 3) specific structural requirements for MAb-adduct binding. In addition, the competitive ELISA provided an accurate determination of BP-6-N7Gua added to normal human urine, at a sensitivity of 200 fmol. 相似文献
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10.
Claudio Fontanesi Roberto Giovanardi Maria Cannio Ercole Soragni 《Journal of Applied Electrochemistry》2008,38(4):425-436
This work presents a study of a hard chromium plating process using low concentration H2CrO4 baths. In particular, the effect of different values of CrO3/H2SO4 ratio on coating properties such as adhesion, hardness, surface roughness, apparent density and microstructure were considered.
To increase the solution conductivity, avoiding long deposition times and low throwing power typical of dilute solutions,
the behaviour of various inorganic compounds was investigated. Specifically, the compounds suitable for obtaining brighter
coatings with lower surface roughness values than those obtained using Fink’s solutions were Na2SO4 and Al2(SO4)3 × 18H2O. A bath composition was identified, with a limited use of Cr(VI) in a solution able to produce coatings with a better surface
roughness than those of conventional industrial baths. 相似文献