Authors:V. Oslovičová, J.R. Simmonds, J.W. Snape, Z. Gálová, Z. Balážová, and I. Matušíková
Morris, C.F., Lillemo, M., Simeone, M.C., Giroux, M.J., Babb, S.L., Kidwell, K.K. 2001. Prevalence of puroindoline grain hardness genotypes among historically significant North American spring and winter wheats. Crop Sci. 41 :218
diameter aluminium probe. The test speed was 55 mm min –1 . Each sample was sliced to 12.5 mm thickness, and for two slices the force (N) required to compress the samples to 25% was measured. Hardness value (N) was evaluated. Colour analysis was determined
Authors:P. Yerlikaya, F.G. Tokay, A.C. Alp, and S. Cilay
5 mm/s from the moment it comes into contact with the surface. Ten repeat measurements were taken for each type of noodles ( n = 10). Hardness (N), cohesiveness (ratio), adhesiveness (Ns), springiness (mm) and chewiness (Nmm) were determined from
Authors:P. Figiel, W. Biedunkiewicz, and D. Grzesiak
by satisfying dispersion of particles in steel matrix and increased hardness comparing to reference sample prepared from 316L steel powder [ 8 ].
In Fig. 3 , the plots of TG u function in time and in Fig. 4 plots of DTG function in
The method described enables the determination of about 8·10−5 Ca which compares favourably with published data obtained by other radiometric methods. In 3 ml solution 0.1 mg of Ca can
be determined with a precision of ±1.5%. Iron does not interfere in moderate concentrations. The method can also be used for
the determination of water hardness in the case of very low hardness values or in turbid or coloured solutions.
DSC investigation has been performed on a Mg–RE–Y–Zr (RE=rare earth) technical alloy WE43. Hardness trend
during isothermal treatments has been correlated to the calorimetric traces
evolution and to the forming β phases with its precursors. Oversaturation
of solute elements occurs at temperatures higher than 150C, on cooling
at room temperature after the anneals. Activation energies, found under non-isothermal
conditions on artificially aged samples, suggest a slow transformation velocity,
while the hardness response is relatively fast.
Authors:J. Felföldi, I. Kertész, D. Nagy, and V. Zsom-Muha
In the case of organic production the quality assessment of the fruits and vegetables is especially important. Monitoring of the maturation and ripening process, early detection of diseases, decision about harvest date and postharvest treatment need reliable, objective and – preferably – non-destructive quality testing methods. Dynamic hardness or stiffness measurement methods (resonance, impact, wave propagation) offer very useful tools in this field, but with strong limitations in applicability area and/or physical interpretation of the measured parameters. Our objective was to develop method and appropriate portable instrumentation to measure surface hardness – as quality measure – with a nondestructive method.
The computer controlled instrument has an electromagnetically excited impactor fitted with a piezoelectric acceleration sensor, a signal conditioner and A/D converter. To ensure the uniform contact behavior (contact area) between the impactor and the tested produce of wide range of shape, spherical head was applied. Conclusively, Hertz contact theory is to be applied for evaluation of the impact signal. Instead of using empirical “hardness index” – as in the case of several existing instruments – our objective was the physical interpretation of the contact phenomena. The measured acceleration signal was mathematically processed to calculate real physical parameters (force, speed, deformation), and to characterize the process similarly to the widely used texture analyzers, penetrometers. A new hardness parameter – “dynamic elastic modulus” – was introduced. According to the methodological investigations, the measurement was found to be perfectly non-destructive for a wide range of products. Conclusively, the developed method offers a useful tool for quality evaluation of organic horticultural products.
Authors:J. Ramana, V. Raju, A. Ray, S. Gangadharan, R. Srinivasa, and A. Chandorkar
Vanadium nitride films were grown on stainless steel and silicon, with different nitrogen concentrations by varying the partial pressures of nitrogen in a DC magnetron sputtering set up. These films were characterized for their composition by proton back-scattering and their micro hardness values were correlated with their N/V ratio.
The effect of various environmental factors on the stability of aqueous solutions of amoxicillin-clavulanic acid combination in a veterinary water-soluble powder product was investigated. In the swine industry, the combination is administered via the drinking water, where both substances are quickly decomposed depending on several environmental factors. The degradation rate of the substances was determined in solutions of different water hardness levels (German hardness of 2, 6 and 10) and pH values (3.0, 7.0 and 10.0), and in troughs made of different materials (metal or plastic). Increasing the water hardness decreased the stability of both substances, amoxicillin being more stable at each hardness value than clavulanate. Amoxicillin trihydrate proved to be most stable at an acidic pH, while increasing the pH decreased its stability (P < 0.05). Maximum stability of potassium clavulanate was experienced at neutral pH, while its decomposition rate was significantly higher at acidic and alkaline pH values (P < 0.01). The stability of the amoxicillin-clavulanic acid combination depends mainly on the less stable clavulanate, although the effect of metallic ions significantly increased the decomposition rate of amoxicillin, rendering it less stable in metal troughs than clavulanate (P < 0.05). Therefore, the amoxicillin-clavulanic acid combination should be administered to the animals in soft water, at neutral pH and in plastic troughs.
Authors:Paola Bassani, E. Gariboldi, and D. Ripamonti
Heat-treatable aluminium alloys are widely used for structural applications. Their strength is obtained through age hardening
phenomena, that are sensitive to microalloying.
In the present paper the results of thermal analyses on the ageing behaviour of an Al-Cu-Mg-Si alloy with silver and zirconium
additions are presented. Specimens were water quenched after solution heat treatment, then aged at 453 K and a hardness-versus-time
plot was drawn. Samples representative of different ageing conditions were subjected to DSC scans.
Peaks were identified taking into account θ and Q phases precipitation sequences. Solution treated samples showed GP/θ″/θ′/Q
sequence, while in peak aged condition GP and θ″ precipitation peaks disappeared and a reduction of θ′ peak area was observed,
witnessing the concurrent presence of θ″ and θ′ phases at peak hardness condition. Experimental data were compared with results
from analogous investigations performed on a conventional commercial Al-Cu-Mg-Si alloy.