Indentation hardness test, performed with either 3 gf or 9 gf loads, preceded the development of microhardness testers using traditional indenters. In 1925, Smith and Sandland of the UK developed an indentation test that employed a square-based pyramidal indenter made from diamond. They chose the pyramidal shape with an angle of 136° between opposite faces in order to obtain hardness numbers that would be as close as possible to Brinell hardness numbers for the specimen. The Vickers test has a great advantage of using one hardness scale to test all materials.The first reference to the Vickers indenter with low loads was made
Scale for the Assessment of Negative Symptoms been developed to assess the positive and negative aspects of schizophrenia. The Scale for the Assessment of Negative Symptoms (SANS) is a rating scale to measure negative symptoms in schizophrenia. The scale was developed by Nancy Andreasen and was first published in 1984. SANS is split into 5 domains, and within each domain separate symptoms are rated from 0 (absent) to 5 (severe). The scale is closely linked to the Scale for the Assessment of Positive Symptoms (SAPS) which was published a few years later. These tools are made available for clinicians and for research purposes. Andreasen NC: Scale for