A study of the mechanisms of corrosion inhibition of AA2024-T3 by vanadates using the split cell technique

The mechanisms of corrosion inhibition of AA2024-T3 by vanadates were studied in this work using the split cell technique and polarization curves. The electrochemical behavior of clear solutions containing metavanadates and orange solutions containing decavanadates was clearly distinctive. Injection of metavanadates to the cathode side of the different split cell setups greatly reduced the galvanic current, indicating a potent inhibition of the oxygen reduction kinetics. The galvanic current never exhibited a transient current peak, suggesting that metavanadates inhibit AA2024-T3 corrosion by a mechanism that does not involve electrochemical reduction. Injection of metavanadate to the anode side of the different split cells had no effect on the galvanic current. Injection of orange decavanadate to the cathode side of the AA2024-T3 split cell resulted in a large current peak, associated with the electrochemical reduction of decavanadate. However, decavanadates did not impart significant corrosion protection.     

Stabilization of the Barkhausen Noise Parameters

The Barkhausen noise was measured in nonoriented Fe–3%Si steel with different average grain sizes. Air gaps between the yoke and the measured objects were also varied during the measurements. The change of the grain size was achieved by different combinations of cold rolling and heat treatment processes. The rise of the gap size degraded the level of the Barkhausen noise and caused that the parameters of the Barkhausen noise, such as the amplitude of the Barkhausen noise's envelope, decreased. In order to suppress the influence of the air gap size on the measurement results, we analyzed the amplitude probability distribution of the Barkhausen noise and we found that the distribution at small levels of the voltage practically does not change with the grain size, but it increases with rise of the gap size. This change of the amplitude probability distribution with the gap size was used to correct the amplitude of the Barkhausen noise's envelope. It was shown that the correction essentially increases the precision of the evaluation of the grain size at varying air gap. Similar technique can be used also to decrease the error of evaluation of other microstructural changes of ferromagnetic materials using the Barkhausen noise method, without measuring and feedback setting the defined waveform of the magnetic field in the sample. For this method to be applicable, several conditions should be met, especially the level of the Barkhausen noise should be essentially higher than the level of the disturbing noise.      

Interdependence of Distortion and Residual Stress Relaxation of Cold-Rolled Bearing Rings During Heating

This article discusses the distortion behavior during heating of bearing rings produced by cold rolling. The residual stress relaxation was characterized intensively and correlated to the distortion behavior. In the initial state, the rings show compressive residual stresses in tangential and axial direction with almost no variations along the circumference. Because of the cold-rolling process, the entire cross section is affected by residual stresses. The rings present a characteristic size change between the soaking temperatures 773 K and 823 K (500 °C and 550 °C), which can be correlated with the macroresidual stress relaxation in the core of the rings. Changes in roundness deviation were found, but the amplitude of oval and triangular shape increases continuously until austenitizing temperature is reached. As the macrostress relaxation is already completed at 873 K (600 °C), another mechanism should be responsible for these distortions. A correlation between amplitude of the oval shape and decrease of full width at half maximum seems to be present. This may indicate that inhomogeneous recrystallization happens along the circumference of the rings. A triangular shape may result from the influence of the loading tool used as rings are positioned on three contact points during the stress relief treatment.     

Identification of halothane genotypes by calcium accumulation and their meat quality using live pigs

The three halothane genotypes (NN, Nn, and nm) were identified by measuring the capacity for Ca²⁺ accumulation by sarcoplasmic reticulum in whole muscle homogenate preparations of M. longissimus dorsi with a Ca²⁺ specific electrode at 35°C. Significant differences (P < 0·001) in deterioration (%) of Ca²⁺ accumulation, 12% for NN, 35% for Nn, and 81% for nn pigs, were observed after ageing the whole muscle homogenate preparations for 24 h in ice.

Predictions of meat quality in live pigs (n = 34) based on the values for water-holding capacity, assessed as fluid (g/0·5 g wet wt LD), and pH (fluid) by using small biopsy LD samples (Cheah et al. 1993) were performed on all the halothane genotypes. The halothane genotype NN (n = 11) showed a fluid value of 0·37 ± 0·01 and a pH (fluid) value of 6·62 ± 0·03 as compared with 0·61 ± 0·02 and 5·84 ± 0·04, respectively, for the halothane genotype nn (n = 13). The Nn pigs (n = 10) showed fluid (0·49 ± 0·03) and pH (fluid) (6·19 ± 0·11) values between those values observed for the two homozygotes (NN and nn). Predictions of meat quality in live pigs from biopsy LD muscles were confirmed from assessments on post-mortem LD muscles based on pH₁ and fibre optic probe (FOP) measurements.

The extent of deterioration (%) in Ca²⁺ accumulation showed high correlations with fluid (r = −0·861) and pH (fluid) (r = −0·831) in the biopsy LD samples, and with pH₁ (r = 0·663), FOP (r = −0·812), and drip (%) loss (r = −0·777) in the post-mortem LD samples.     

Shock

Shock is a consequence of disturbed circulation and decreased blood perfusion of tissues which, on the whole, cause functional and morphological impairments of organic systems. Occurrence of shock is not high, but it is significant due to bad prognosis and high mortality rate. CLASSIFICATION: This is one of the classifications of shock: cardiogenic, extracardiogenic-obstructive, oligentic and distributive shock. PATHOPHYSIOLOGIC MECHANISMS OF SHOCK: Regardless of the cause of shock, the clinical picture is dominated by hypotension mostly caused by decrease of minute volume (septic shock may be an exception--minute volume might be high). Due to hypotension a lot of compensatory mechanisms are activated and in the beginning showing the compensatory phase of disease and if nothing is done decompensatory and in the end irreversible phase of shock occurs with fatal outcome. The clinical picture depends on the etiology of shock, type of shock, but it also has certain specificities. PROGNOSIS: The prognosis depends on the clinical picture dominated by the following symptoms: hypotension, decreased diuresis, acidosis, consciousness disorders, tachypnea, peripheral cyanosis, cold and damp skin. MANAGEMENT: These patients are managed in intensive care units, where the following parameters are followed-up: arterial pressure, central venous pressure, minute heart volume, systemic vascular resistance, diuresis, continual follow-up of heart rate, breathing and consciousness. In treatment of shock it is necessary to: normalize the circulatory volume, establish electrolyte balance, regulate glycemia and acid-base status, compensate the volume, calm the patient and alleviate pain.     

Hydrolysis and esterification of acylglycerols and analogs in aqueous medium catalyzed by microbial lipases

The stereoselectivity of microbial lipases from Chromobacterium viscosum (CVL) and Rhizopus arrhizus (RAL) towards monoacylglycerols (rac-1(3)-oleoylglycerol and 2-oleoylglycerol), diacylglycerols (1,3-dioleoylglycerol and rac-1,2(2,3)-dioleoylglycerol) and 2-O-ether analogs (rac-1(3)-oleoyl-2-O-hexadecylglycerol and rac-1(3)-octanoyl-2-O-hexadecylglycerol) was determined. The results of the hydrolysis of 2-O-ether analogs confirmed the importance of the substituent at C-2 of acylglycerols in the stereoselective recognition by microbial lipases and also showed that acylation of mono- and diradylglycerols with oleic acid overlaps the hydrolysis reaction in aqueous medium. With the short-chain, water-soluble octanoic acid no significant esterification occurred. Using rac-1,2(2,3)-dioleoylglycerol as a substrate for the hydrolysis with RAL and CVL, the appearance of 1,3-dioleoylglycerol and of 1(3)-monooleoylglycerol was demonstrated. The possibility of chemical vs. enzyme-catalyzed isomerization of 1,2-dioleoylglycerol and of 2-oleoylglycerol is discussed.     

Susceptibility of meat lactic acid bacterla to antibiotics

In APT broth culture penicillin was more inhibitory to frozen-thawed meat lactic acid bacteria (MIC of 1·3 to 5·0 μg ml⁻¹) than, in decreasing order of inhibition, chlortetracycline, neomycin and streptomycin. Streptomycin, chlortetracycline and neomycin inhibited the fermentative activity of P. pentosaceus more than penicillin and neomycin was most inhibitory to L. plantarum. The fermentative activity of P. pentosaceus, in meat, was inhibited by antibiotics more than that of L. plantarum (90 vs 30%).     

Simulation of statistical variability in nano-CMOS transistors using drift-diffusion, Monte Carlo and non-equilibrium Green’s function techniques

In this paper, we present models and tools developed and used by the Device Modelling Group at the University of Glasgow to study statistical variability introduced by the discreteness of charge and matter in contemporary and future Nano-CMOS transistors. The models and tools, based on Drift-Diffusion (DD), Monte Carlo (MC) and Non-Equilibrium Green’s Function (NEGF) techniques, are encapsulated in the Glasgow 3D statistical ‘atomistic’ device simulator. The simulator can handle most of the known sources of statistical variability including Random Discrete Dopants (RDD), Line Edge Roughness (LER), Thickness Fluctuations in the Oxide (OTF) and Body (BTF), granularity of the Poly-Silicon (PSG), Metal Gate (MGG) and High-κ (HKG), and oxide trapped charges (OTC). The results of the statistical simulations are verified with respect to measurements carried out on fabricated devices. Predictions about the magnitude of the statistical variability in future generations of nano-CMOS devices are also presented.     

W5O14 Nanowires

We report on the synthesis of quasi‐1D W₅O₁₄ crystals using NiI₂ as a growth promoter. Photoelectron spectroscopy revealed the metallic conductivity of the W₅O₁₄ nanowires, which was also confirmed by direct‐transport measurements on a double‐stranded nanowire. Scanning electron microscopy and transmission electron‐diffraction data are correlated with details of crystal growth revealing the possible mechanism of the formation of this rarely synthesized phase, which was reported as a homogeneous phase only in 1978 by McColm et al., and in the meantime has been declared as a compound that is rare.