Grain size effect on behaviour and microstructure of a warm deformed Ti-IF steel

The effect of grain size on the deformation behaviour in the fenite region of a Titanium stabilized Interstitial Free steel was investigated by hot torsion. The initial work hardening regime is followed by a softening regime where a broad peak stress develops. The peak stress and the stress at final strain were relatively insensitive to grain size. However, at low values of the Zener-Hollomon parameter, the strain to the peak stress was strongly dependent on the grain size. A series of microstructural parameters were examined to explain these observations.

Improving golf performance with a warm up conditioning programme

Objectives: To determine whether a golf specific warm up programme (both immediately prior to play and after performing it five times a week for 5 weeks) improved performance in 10 male golfers compared with 10 controls matched for age, sex, and handicap.

Methods: Twenty male golfers were matched for age (±2 years) and handicap (±1 stroke). Club head speed was assessed by two dimensional video analysis in a laboratory setting. In week 1, all golfers performed 10 strokes. In weeks 2 and 7, the controls underwent the same procedure as in week 1. The exercise group performed the golf specific warm up followed by their 10 strokes. Between weeks 2 and 7, the exercise group performed the specially designed warm up five times a week for 5 weeks.

Results: The mean club head speeds of the exercise group improved at each testing week. Between weeks 1 and 2, golfers in the exercise group improved their club head speed on average by 3–6 m/s (12.8%), and between weeks 1 and 7, they increased their club head speeds by 7–10 m/s (24.0%). With the exception of one golfer whose club head speed varied by 1.7 m/s, the mean club head speeds of the golfers in the control group hardly varied over the testing period (range: 0.3–0.8 m/s). A significant difference (p = 0.029) was found between the mean club head speeds of the exercise and control groups over the duration of the study, and a significant interaction over time (p<0.001) was also found.

Conclusions: This study has shown that golfers’ performances will be significantly improved by undertaking a golf specific warm up programme compared with not performing the warm up.

Grain size effect on the warm deformation behaviour of a Ti-IF steel

The effect of grain size on the warm deformation behaviour of a titanium stabilized interstitial free (IF) steel was investigated using hot torsion. The initial work hardening regime is followed by the development of a broad stress peak after which work softening occurs. The hypothetical saturation stress (Estrin–Mecking model) and the stress at final strain were relatively insensitive to grain size. However, the strain to the peak stress was strongly dependent on the grain size at low values of the Zener–Hollomon parameter. A simple phenomenological approach, using a combined Estrin–Mecking model and an Avrami type equation, was used to model the flow curves. The hypothetical saturation stress, the stress at final strain and the strain to peak stress were modelled using three different hyperbolic sine laws. A comparison with independent data from the literature shows that the apparent activation energy of deformation determined in this work (Q=372 kJ/mol) can be used to rationalize the steady-state stress in compression data found in the literature.

Identification of an integral plasma membrane pool of protein kinase C in mammalian tissues and cells

Protein kinase C (PKC) is a family of serine/threonine protein kinases that are pivotal in cellular regulation. Since its discovery in 1977, PKCs have been known as cytosolic and peripheral membrane proteins. However, there are reports that PKC can insert into phospholipids vesicles in vitro. Given the intimate relationship between the plasma membrane and the activation of PKC, it is important to determine whether such “membrane-inserted” form of PKC exists in mammalian cells or tissues. Here, we report the identification of an integral plasma membrane pool for all the 10 PKC isozymes in vivo by their ability to partition into the detergent-rich phase in Triton X-114 phase partitioning, and by their resistance to extractions with 0.2 M sodium carbonate (pH 11.5), 2 M urea and 2 M sodium chloride. The endogenous integral membrane pool of PKC in mouse fibroblasts is found to be acutely regulated by phorbol ester or diacylglycerol, suggesting that this pool of PKC may participate in cellular processes known to be regulated by PKC. At least for PKCα, the C2–V3 region at the regulatory domain of the kinase is responsible for membrane integration. Further exploration of the function of this novel integral plasma membrane pool of PKC will not only shed new light on molecular mechanisms underlying its cellular functions but also provide new strategies for pharmaceutical modulation of this important group of kinases.

Dynamic softening of ferrite during large strain warm deformation of a plain-carbon steel

The evolution of dynamic ferrite softening in a plain-carbon steel was investigated by torsion tests during warm deformation at 810 °C, in the two-phase (ferrite + austenite) region, and strain rate of 0.1 s−1 with different strains up to 50. The warm flow behaviour and ferrite microstructural parameters, such as grain size, misorientation angle across ferrite/ferrite boundaries, and the fraction of high-angle and low-angle grain/subgrain boundaries were quantified using electron back scatter diffraction. The results show that with increasing strain up to not, vert, similar2, the ferrite grain size and fraction of high-angle boundaries rapidly decrease and the fraction of low-angle boundaries increases. However, these parameters remain approximately unchanged with increasing strain from not, vert, similar2 to 50. The dynamic softening mechanism observed during large strain ferritic deformation is explained by dynamic recovery and continuous dynamic recrystallization.

Characterization on ferrite microstructure evolution during large strain warm torsion testing of plain low carbon steel

Ferrite grain/subgrain structures evolution during the extended dynamic softening of a plain low carbon steel was investigated throughout the large strain warm deformation by hot torsion. Microstructural analysis with electron back-scattering diffraction (EBSD) scanning electron microscope (FEG/SEM) was carried out on the ferrite microstructural parameters. The results showed that the warm flow stress–strain curves are similar to those affected only by dynamic softening and an extended warm flow softening is seen during large strain deformation up to 30. Furthermore, with an increase in strain up to ~ vert, similar1 the grain size of ferrite, misorientation angle and fraction of high-angle boundaries gradually decrease and fraction of low-angle boundaries increases. With a further increase in the strain beyond ~, vert, similar2, these parameters remain approximately unchanged. No evidence of discontinuous dynamic recrystallisation involving nucleation and growth of new grains was found within ferrite. Therefore, the dynamic softening mechanism observed during large strain ferritic deformation is explained by continuous dynamic recrystallization (CDRX).

Contingent valuation in health care and the persistence of embedding effects without the warm glow

This paper reports a test of the presence of embedding effects in a health care contingent valuation study. A within-subject, mixed qualitative–quantitative approach was used to identify and explain the presence of embedding in estimates of willingness to pay for vaccinations. Embedding effects persisted despite controlling for known causes and did so even among respondents who perceived the effect to be anomalous. Results from the qualitative interviews suggest that embedding effects arise for varied reasons but might be indicative of incomplete preferences. It is questionable, however, whether survey techniques can be better designed to encourage values clarification.