Low temperature impact strength of heavy section ductile iron castings: effects of microstructure and chemical composition

A foundry research project has been recently initiated at RTIT in order to better understand the fabrication of as-cast heavy section DI parts meeting high impact energy requirements at low temperatures. The experimental castings have the following dimensions 180 mm x 180 mm x 190 mm. The achieved as-cast Charpy impact strengths were as follows: 17 J (RT), 16 J (-20°C) and 11 J (-40°C). The foundry process, the chemical composition and the microstructure of this experimental casting are compared to the ones of various examples in order to show the detrimental effects of residual elements, microshrinkage and microcarbide on the impact properties. Finally, quality index empirical models (based on casting chemical compositions) are used to analyse the impact tests results. This paper illustrates that an adequate nodule count can contribute to reducing the detrimental effects of the residual elements and microsegregation

How a new inmate triage system could reduce the use of solitary confinement and improve prison safety

Across the political spectrum in the United States, there are growing concerns regarding the effectiveness and utility of solitary confinement - a practice also referred to as restrictive housing. However, for a country that has grown reliant on the use of solitary confinement in its prisons, there are still more questions than answers about how to reduce its use while also ensuring institutional safety and security. Ryan M. Labrecque created a new tool for use by corrections staff to triage inmates by risk. He argues that this tool can be effective in reducing the use of restrictive housing and increasing prison safety by proactively targeting high-risk inmates for treatment services upon their entry into the prison system

Sex Attraction in the House Fly, Musca Domestica L.

Author Institution: Entomology Research Division, Agric. Res. Serv., U.S.D.A., Gainesville, Fla.Attraction tests have shown that virgin female house flies attract both virgin males and females but the degree of attraction is relatively small. A tentative hypothesis of chemical sex attraction is suggested. The attraction does not appear to be due to moisture, motion, or sound effects

Studies on the Mating Behavior of the House Fly, Musca Domestica L.

Author Institution: Entomology Research Division, Agric, Res. Serv., U.S.D.A. Gainesville, Fla

The effects of childbirth on the pelvic-floor

Basically, vaginal delivery is associated with the risk of pelvic floor damage. The pelvic floor sequelae of childbirth includes anal incontinence, urinary incontinence and pelvic organ prolapse. Pathophysiology, incidence and risk factors for the development of the respective problems are reviewed. Where possible, recommendations for reducing the risk of pelvic floor damage are given

Morphology and tectonics of the Mid-Atlantic Ridge, 7°–12°S

We present swath bathymetric, gravity, and magnetic data from the Mid-Atlantic Ridge between the Ascension and the Bode Verde fracture zones, where significant ridge–hot spot interaction has been inferred. The ridge axis in this region may be divided into four segments. The central two segments exhibit rifted axial highs, while the northernmost and southernmost segments have deep rift valleys typical of slow-spreading mid-ocean ridges. Bathymetric and magnetic data indicate that both central segments have experienced ridge jumps since ~1 Ma. Mantle Bouguer anomalies (MBAs) derived from shipboard free air gravity and swath bathymetric data show deep subcircular lows centered on the new ridge axes, suggesting that mantle flow has been established beneath the new spreading centers for at least ~1 Myr. Inversion of gravity data indicates that crustal thicknesses vary by ~4 km along axis, with the thickest crust occurring beneath a large axial volcanic edifice. Once the effects of lithospheric aging have been removed, a model in which gravity variations are attributed entirely to crustal thickness variations is more consistent with data from an axis-parallel seismic line than a model that includes additional along-axis variations in mantle temperature. Both geophysical and geochemical data from the region may be explained by the melting of small (<200 km) mantle chemical heterogeneities rather than elevated temperatures. Therefore, there may be no Ascension/Circe plume

Low-Resolution Imaging Spectrometer for the Keck Telescope

The Low Resolution Imaging Spectrometer is designed for use at the Cassegrain focus of the Keck 10-m telescope. It provides the capability of acquiring low resolution (R equals 1000 to 5000) digital spectra, as well as 6 X 8 arc-minute moderately high spatial resolution (4.65 pixels/arc-second) direct images. Spectroscopy can be carried out with single slits which are 3 arc-minutes long. In addition punched multi-slits can also be employed which allow for the acquisition of at least forty spectra simultaneously. Since the instrument is designed to be as efficient as possible, it is a double spectrograph, with a dichroic splitting the blue and red light into separate optical paths after the collimator. Only the red side has been constructed thus far. With a 2048 by 2048 thinned Tektronix CCD as the detector the total efficiency of the red side at the peak of the grating blaze is predicted to be nearly 40%. Results of the commissioning observing runs will be described