Final report of grit blasting and metal spraying trials carried out at H. M. Dockyard, Devonport

Mild steel surfaces that are to be protected by aluminium or zinc spray coatings are generally prepared by blasting with chilled iron angular grit. Previous work1had shown that a relationship exists between the grit blasting conditions (at least in terms of blasting angle and grit condition), the reflectivity of the blasted surface and the bond strength of a spray coating of aluminium on the blasted surface. An instrument has been developed that assesses the suitability of a blasted surface for subsequent spraying by measuring the reflectivity and has proved reasonably successful under laboratory conditions. The present need is to ascertain the performance of this reflectivity meter under shop and site conditions. The opportunity to carry out such tests at H.M. Dockyard, Devonport, was offered by the Ministry of Defence and a series of tests was made on 16th June, 1965

The use of process selection exercises for the training of welding technologists

Formal lectures and laboratory experiments do not give students sufficient experience of welding processes applied to specific fabrications. A series of designs has been evolved which ib.capable of being fabricated by several different methods and students are required to produce fabrication procedures for each design. Suggested procedures are then discussed in an open forum in which both staff and students participate. The use of these exercises has been found to be a useful method whereby course members can pass on their own experience to other students and in which students learn to make decisions based on available, but often incomplete, facts

Measurement of thermal cycles in the weld heat affected zone of mild steel

The thermal cycles in the mild steel parent plate adjacent to a bead on plate weld have been measured for heat inputs of 108, 54 and 42 kJ/inch, by means of embedded thermocouples connected to high response automatic recorders. The results show that decreasing the heat input increases the cooling rate and decreases the width of the heat affected zone. For thermal cycles in which the peak temperatures reached 900°C or above, two points of inflection have been noted in the temperature ranges 400° - 600°C and 950° - 1200°C. The inflection in the lower temperature range, which has been observed by other workers, has been attributed to latent heat from the exothermic transformation of austenite to ferrite. The higher inflection point, not previously reported, has been tentatively related to the solidification in the weld pool and the release of the latent heat of fusion

Effectiveness of a social support intervention on infant feeding practices : randomised controlled trial

Background: To assess whether monthly home visits from trained volunteers could improve infant feeding practices at age 12 months, a randomised controlled trial was carried out in two disadvantaged inner city London boroughs. Methods: Women attending baby clinics with their infants (312) were randomised to receive monthly home visits from trained volunteers over a 9-month period (intervention group) or standard professional care only (control group). The primary outcome was vitamin C intakes from fruit. Secondary outcomes included selected macro and micro-nutrients, infant feeding habits, supine length and weight. Data were collected at baseline when infants were aged approximately 10 weeks, and subsequently when the child was 12 and 18 months old. Results: Two-hundred and twelve women (68%) completed the trial. At both follow-up points no significant differences were found between the groups for vitamin C intakes from fruit or other nutrients. At first follow-up, however, infants in the intervention group were significantly less likely to be given goats’ or soya milks, and were more likely to have three solid meals per day. At the second follow-up, intervention group children were significantly less likely to be still using a bottle. At both follow-up points, intervention group children also consumed significantly more specific fruit and vegetables. Conclusions: Home visits from trained volunteers had no significant effect on nutrient intakes but did promote some other recommended infant feeding practices

Planetary Companions Around Two Solar Type Stars: HD 195019 and HD 217107

We have enlarged the sample of stars in the planet search at Lick Observatory. Doppler measurements of 82 new stars observed at Lick Observatory, with additional velocities from Keck Observatory, have revealed two new planet candidates. The G3V/IV star, HD 195019, exhibits Keplerian velocity variations with a period of 18.27 d, an orbital eccentricity of 0.03 +/- 0.03, and M sin i = 3.51 M_Jup. Based on a measurement of Ca II H&K emission, this star is chromospherically inactive. We estimate the metallicity of HD 195019 to be approximately solar from ubvy photometry. The second planet candidate was detected around HD 217107, a G7V star. This star exhibits a 7.12 d Keplerian period with eccentricity 0.14 +/- 0.05 and M sin i = 1.27 M_Jup. HD 217107 is also chromospherically inactive. The photometric metallicity is found to be [Fe/H] = +0.29 +/- 0.1 dex. Given the relatively short orbital period, the absence of tidal spin-up of HD 217107 provides a theoretical constraint on the upper limit of the companion mass of < 11 M_Jup.Comment: 15 pages, plus 6 figures. To appear in Jan 1999 PAS

Cerebellar modulation of memory encoding in the periaqueductal grey and fear behaviour

The pivotal role of the periaqueductal grey (PAG) in fear learning is reinforced by the identification of neurons in male rat ventrolateral PAG (vlPAG) that encode fear memory through signalling the onset and offset of an auditory-conditioned stimulus during presentation of the unreinforced conditioned tone (CS+) during retrieval. Some units only display CS+ onset or offset responses, and the two signals differ in extinction sensitivity, suggesting that they are independent of each other. In addition, understanding cerebellar contributions to survival circuits is advanced by the discovery that (i) reversible inactivation of the medial cerebellar nucleus (MCN) during fear consolidation leads in subsequent retrieval to (a) disruption of the temporal precision of vlPAG offset, but not onset responses to CS+, and (b) an increase in duration of freezing behaviour. And (ii) chemogenetic manipulation of the MCN-vlPAG projection during fear acquisition (a) reduces the occurrence of fear-related ultrasonic vocalisations, and (b) during subsequent retrieval, slows the extinction rate of fear-related freezing. These findings show that the cerebellum is part of the survival network that regulates fear memory processes at multiple timescales and in multiple ways, raising the possibility that dysfunctional interactions in the cerebellar-survival network may underlie fear-related disorders and comorbidities