Materials Literature
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The dryout heat flux applicable to light water reactor fuel elements covered with porous deposits characterized by the presence of “steam channels,” or chimneys, is determined by the “wicking” or “choking” limit. The results of a study of these limits show that the dryout heat flux for thick, dense, or small particle…
Knowledge of the effective multiplication factor (keff) of variously configured damaged fuel at Three Mile Island Unit 2 (TMI-2) has greatly affected ongoing defueling operations. A recent DOT 4.3 discrete ordinates analysis has extended prior postaccident analyses of keff to “best-estimate”predictions of criticality…
Abstract The regularities of thermal degradation of Al(OH) 3 powders and the compositions of polydimethylsiloxane and fire retardant with different particle sizes (from 2 μm to 45 μm) were studied by the use of dynamic thermogravimetry (TG), mass spectrometry (MS) and high‐temperature pyrolysis. It was shown that the…
Abstract Recent studies have shown that the amount and rate of absorption of gases and organic liquids and vapors in rigid and plasticized PVC can be correlated with their molecular dimensions, solvent power, and thermodynamic activity. The amount absorbed at equilibrium depends upon the solvent power of the diffusant…
The electrical impedance of a disc-shaped sample of polycrystalline UO2 has been measured over a frequency range of 10 Hz to 10 MHz at temperatures between 108 and 380 K. Three distinct regions in the impedance profiles were observed; these have been associated with the region near the metallic electrodes, with the bu…
The successful preparation of Ta2S2C at 1150 °C has been found to be intimately linked to the presence of halogens in the reaction. Adventitious chlorine obtained either through the use of excess carbon or of graphite crucibles was apparently responsible for previously successful reactions. The purposeful introduction…
Abstract Unsymmetrically quinone-substituted porphyrin dimers were synthesized. The fluorescence of the both porphyrins in these models was effectively quenched by the attached quinone.
The Amphora species epiphytic on some freshwater species of fibulate diatoms is investigated and allocated to Amphora copulata var. epiphytica var. nov.
This study is the first to make a direct comparison between the distorting mirror and the distorting videocamera with the same group of nonclinical subjects. It also establishes the internal consistency, the test-retest reliability and the convergent validity of both techniques. Analysis indicates, as with other studi…
Stable icosahedral phases of Al-Fe-Cu and Al-Li-Cu, which are recognized as icosahedral quasicrystals corresponding to face-centered and simple 6D-hypercubic lattices, respectively, were examined by high-resolution electron microscopy with the incident beam parallel to the two-fold symmetry axis. Images observed were…
Abstract Polymandelide was prepared in 77% yield by reaction of α‐bromophenylacetic acid and triethylamine. The product was characterized by 1 H‐ and 13 C‐NMR and IR spectra and isolation and identification of mandelic acid from hydrolysis of the polymer. The NMR spectra indicate the presence of tacticity at CH in the…
TODAY'S modern aeroplanes require light weight components to satisfy the aeroplane's flight performance requirements. More than ever before new designs require commercially pure titanium (Grades A40, A55, and A70) because of the needs for high ductility associated with moderate strength, high corrosion resistance and…
The adsorption of polymeric sulphonated naphthalene formaldehyde (SNF) and sulphonated melamine formaldehyde (SMF) on to titanium dioxide and calcium carbonate has been measured in aqueous media. The magnitude of these adsorptions is strongly dependent on electrostatic interaction irrespective of the pH value. This re…
Long-distance transport of 14C-labelled (photo)assimilates was studied in Fucus serratus. Movement of label followed the source-sink relationship: the growing apical regions of this alga acted as a strong sink. The distribution of the 14C translocate, as determined from the low molecular weight fraction of the midrib,…
Hydrogen permeation and diffusivity were studied electrochemically at temperatures between 283 and 343 K at constant current for annealed and hardened AISI 420 and annealed AISI 430 stainless steel. Permeation rate, effective diffusivity, and solubility were calculated from these data. Annealed AISI 420 shows higher p…
This paper is concerned with the optimization of a double-rove spinning process in the short staple spinning system, using Box and Hunter's technique of a central compound rotatable design. The influences of strand spacing, twist, and spindle speed on yarn tensile and regularity properties are discussed.
Etude par microscopie electronique en transmission de la non stoechiometrie, des phenomenes d'intercroissance et des assemblages des differentes couches dans les mineraux du titre de formule generale M 8 O 12 (M=Mn,Fe,Ca,Si)
An update of the taxa assigned to the genus Mastogloia is given. An estimated 410 taxa have been described as at November 1988. A cross-reference database of the similarities existing between 164 recently described taxa and 83 well-known ones is also reported. This may facilitate the identification of troublesome spec…
Abstract Alkylammonium benzene-, pyridine-3-, p-toluene-, and p-ethylbenzenesulfonates were found to be smectogenic when the cation carries an octyl or longer alkyl group. The thermal stability of the mesophase usually reaches its maximum at the octadecylammonium salt. The temperature range of stable existence is in t…
Steady-state and transient photoconductivity measurements have been made at different temperatures and intensities on the amorphous and partially crystallised films of Se 75 Te 25 prepared by vacuum evaporation. Partial crystallisation is achieved by annealing the films at a particular temperature near the crystallisa…