Physical Properties of Dentin

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66560/2/10.1177_00220345520310031401.pd

Microstructure of Dental Amalgams Containing High and Low Copper Contents

Microstructure of commercial dental alloys and their amalgams were studied primarily by x-ray diffraction, optical metallography, scanning electron microscopy, and x-ray energy dispersive spectroscopy. X-ray diffraction revealed more phases than normally reported in these materials. Presence of new phases was discussed and their formation mechanism understood. Some phases having interacting 2θ° values with others were properly identified. Both new and conventional dental alloys and their amalgams, namely Tytin, Sybraloy, Dispersalloy, Kerr Spheraloy, Caulk Spherical, Shofu Spherical, and Caulk 20th Century Microcut were used to complete the investigation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67943/2/10.1177_00220345770560121001.pd

The Behavior and Measurement of Hygroscopic Expansion of Dental Casting Investment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67033/2/10.1177_00220345540330041201.pd

The Volumetric Contraction of Dental Gypsum Materials on Setting

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67364/2/10.1177_00220345530320030801.pd

Photoelasticity as a Research Technique for Analyzing Stresses in Dental Structures

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67063/2/10.1177_00220345550340060601.pd

Initiation of Cracks in Dental Amalgam

The force required to initiate cracks in dental amalgam beams was measured and related to the microstructure. The force measured was dependent on age and on the distribution of phases on the tension side of the beam. The Ag-Cu phase is most resistant to failure in Dispersalloy and an experimental alloy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67365/2/10.1177_00220345750540060601.pd

X-ray Diffraction Analysis of γ2 (Sn-Hg) Phase in High Copper Amalgams of Varying Mercury Content

Microstructures of high copper commercial amalgams containing varying amounts of mercury, ranging from 20% above to 25% below recommended values, were primarily investigated by x-ray diffraction. Mechanisms relating to the absence or presence of γ2 (Sn-Hg) phase in these amalgams were discussed in relation to the presence of copper and tin elements in their original alloys. The optimum mercury concentration in some amalgams was determined in order to keep them free of the γ2 (Sn-Hg) phase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66731/2/10.1177_00220345810600021001.pd

Resposta da produtividade de grãos e outras características agronômicas do trigo EMBRAPA-22 irrigado ao nitrogênio em cobertura

As doses e a época de aplicação do nitrogênio (N) podem influenciar as características agronômicas do trigo (Triticum aestivum L.) irrigado e, conseqüentemente, a produtividade de grãos. Neste sentido, foram instalados dois experimentos na Estação Experimental da Universidade Federal de Viçosa, localizada em Coimbra (MG), em 1995 e 1996. Os tratamentos foram constituídos pela combinação de quatro doses de N (30, 60, 90 e 120 kg ha-1), quatro formas de parcelamento (dose total aos 20 dias da emergência (DAE); ½ aos 20 + ½ aos 40 DAE; 1/3 aos 20 + 2/3 aos 40 DAE e 2/3 aos 20 + 1/3 aos 40 DAE) e uma testemunha (sem N em cobertura), dispostos em esquema fatorial 4 x 4 + 1, no delineamento em blocos casualizados com quatro repetições. A altura e o acamamento das plantas, a biomassa seca, o índice de colheita, a massa de mil grãos, o peso hectolítrico e a produtividade de grãos foram influenciados pelas doses de N. Em 1996, o número de espigas por metro quadrado e o número de perfilhos férteis por planta diminuíram, em conseqüência do acamamento precoce das plantas, enquanto o número de grãos por espiga e o número de grãos por metro quadrado aumentaram com o incremento nas doses de N. As formas de parcelamento influenciaram somente o acamamento das plantas