Blow Forming Research Articles

Analytical prediction of pressure‐time curve for free inflation of superplastic sheet into hemispherical dome

Abstract Blow forming is a commonly used production method to deform superplastic sheets. Several papers have appeared to analytically predict the pressurization sequence needed to control the inflation process at a desired strain rate. Some of them, however, are based on an over‐simplified assumption of uniform thickness reduction during the inflation, which often leads to non‐conservative prediction of pressure‐time path. Others have been more rigorous in the formulation, which on the other hand, results in more extensive equations requiring iterative method with a computer program. This paper presents a modified approach. Ignoring the assumption of uniform thinning, a set of physically sound yet easy‐to‐use equations for obtaining pressure‐time curves, heights of the deforming dome, and thickness variations both in space and time, are derived. The analytical results compare favorably with the experimental data and more elaborate finite element solutions.

Identifying and Helping Battered Pregnant Women

This article highlights strategies in identifying and helping battered pregnant women. Studies report that 40-60% of battered women were abused during pregnancy inflicted in the form of blows to the abdomen, injuries to the breasts and genitals, and sexual assault. Because battering during pregnancy has been a prevalent occurrence, assessment during prenatal visits is most critical. This paper outlines several assessment approaches in dealing with battered pregnant women in specific circumstances, giving important consideration to her safety due to the potential risk of homicide. A Danger Assessment tool is utilized in assessing for potential homicide. Intervening with victims of abuse is difficult. The role of the nurse is to assist in the development of problem-solving and decision-making skills while the woman is still in extreme confusion or feeling of conflicting loyalties. Routine assessment for physical and sexual abuse during the prenatal period is recommended in order to prevent further abuse thus promoting maternal-child well being.

Evidence for episodic sand-blow activity during the 1811-1812 New Madrid (Missouri) earthquake series

Four major earthquakes of the 1811-1812 New Madrid series caused widespread ground disturbance, mostly in the form of sand blows, in the alluvial valley of the Mississippi River. Although a recurrence interval of 600-700 yr has been estimated for major shocks, recent excavations at an archeological site in northeastern Arkansas revealed no evidence of ground disturbance for at least 1.3 ka prior to 1811. Sand blows attributed to the New Madrid series show that such features can have multiple episodes of sand extrusion through a single dike and vent.