Thermisch harden van glas

A review with 9 refs. The background of thermal hardening is discussed. Thermal prestressing is the most important method available for increasing the strength of flat glass. The topics include: introduction; phys. description of thermal prestressing of glass; effect of glass properties and process parameters on prestressing; practical aspects; and conclusions. [on SciFinder (R)

Planaire optische versterkers

Langs een glasfiber kan in de vorm van optische pulsjes verschrikkelijk veel informatie worden verzonden: de fiber heeft een zeer hoge transmissiecapaciteit. Wanneer echter voor het schakelen van de informatiestroom, of voor het regenereren van de pulsjes, de informatiestroom naar het elektrische domein omgezet moet worden en vice versa, geeft dit een enorme verlaging van deze capaciteit. Door drie Nederlandse groepen, wordt gedeeltelijk onder de paraplu van het IOP onderzoek gedaan aan een speciale klasse van planaire versterkers: nl die waarin de versterking berust op eigenschappen van zeldzame aard ionen zoals het Erbium-ion. En over dit onderzoek gaat dit artikel

Thermal behaviour of glass batch on batch heating

The heating process of a Ba-Sr glass batch was studied in a 40 L pot furnace, using a multiple thermocouple assembly. The effect of several batch parameters on the heating process was measured, including layer thickness, cullet fraction, water content, and pellets. The results were evaluated using a heat penetration batch model. In the model 2 heating stages, below and above a certain batch transition temp., ns, typically 800 to 900 Deg, are distinguished. Values for the temp.-dependent thermal diffusivity of the batch were derived from exptl. temp. distributions in the batch during heating. Below ns, the thermal diffusivity has an almost const. value of 0.4 * 10-6 m2/s for a std. (powder) batch blanket; for n > ns, the net thermal diffusivity strongly increases with temp., due to the formation of primary melt phases. For ns <n <1100 Deg, the av. value is about 1.4 * 10-6 m2/s. A 100% cullet layer has a 50% higher thermal diffusivity for n <ns; pelletizing the batch has little influence on the virtual thermal diffusivity and (extra) wetting has a retarding effect on batch heating due to extra heat absorption. As for the furnace temp., it appears that increasing the temp. of the glass melt is more effective for improving the batch heating rate than increasing the temp. of the combustion chamber. Practical recommendations are given for batch prepn., charging, and heating in industrial glass tanks. [on SciFinder (R)

Pr3+-doped GeSx-based glasses for fiber amplifiers at 1.3 mm

The luminescence of Pr3+-doped GeSx-based glasses were studied and compared with those of other sulfide and fluoride glasses. The possibility of highly pump-power-efficient fiber amplifiers based on these GeSx-contg. glasses in the telecommunications window at 1.3 mm is discussed. [on SciFinder (R)

Pr3+-doped GeSx-based glasses for fiber amplifiers at 1.3 mm

The luminescence of Pr3+-doped GeSx-based glasses were studied and compared with those of other sulfide and fluoride glasses. The possibility of highly pump-power-efficient fiber amplifiers based on these GeSx-contg. glasses in the telecommunications window at 1.3 mm is discussed. [on SciFinder (R)

Are torso asymmetry and torso displacements in a computer brace model associated with initial in-brace correction in adolescent idiopathic scoliosis?

Background: Lack of initial in-brace correction is strongly predictive for brace treatment failure in adolescent idiopathic scoliosis (AIS) patients. Computer-aided design (CAD) technology could be useful in quantifying the trunk in 3D and brace characteristics in order to further investigate the effect of brace modifications on initial in-brace correction and subsequently long-term brace treatment success. The purpose of this pilot study was to identify parameters obtained from 3D surface scans which influence the initial in-brace correction (IBC) in a Boston brace in patients with AIS.Methods: Twenty-fiveAIS patients receiving a CAD-based Boston brace were included in this pilot study consisting of 11 patients with Lenke classification type 1 and 14 with type 5 curves. The degree of torso asymmetry and segmental peak positive and negative torso displacements were analyzed with the use of patients’ 3D surface scans and brace models for potential correlations with IBC. Results: The mean IBC of the major curve on AP view was 15.9% (SD = 9.1%) for the Lenke type 1 curves, and 20.1% (SD = 13.9%) for the type 5 curves. The degree of torso asymmetry was weakly correlated with patient’s pre-brace major curve Cobb angle and negligible correlated with major curve IBC. Mostly weak or negligible correlations were observed between IBC and the twelve segmental peak displacements for both Lenke type 1 and 5 curves.Conclusion: Based on the results of this pilot study, the degree of torso asymmetry and segmental peak torso displacements in the brace model alone are not clearly associated with IBC.</p