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Structure loss impairs the quality of monocrystalline ingots and represents a major productivity loss for crystal growers. If structure loss could be predicted in advance it could help reduce the lost production time or preventive measures could be initiated. For this reason, feature engineering and machine learning by long short-term memory (LSTM) is used to assess if structure loss could be predicted from sensor data collected during growth of ingots. The method is not able to predict structure loss in advance, and the predictions may likely be based on the length of the signal, which is shortened for structure loss ingots as their growth is interrupted, and not actual features in the sensor readings.

In the production of monocrystalline silicon by the Czochralski process, structure loss frequently reduces yield and increases production time. Structure loss means the transition from monocrystalline to multicrystalline structure. It is typically preceded by generation of dislocations and slip. Previous work concluded that a pinhole (i.e. a cavity from gas bubble in the melt) was the main cause of structure loss in an n-type Czochralski ingot. In the present study, seven industrial n-type Czochralski silicon ingots were investigated to assess whether pinholes frequently contribute to cause structure loss. Pinholes were found within 5 cm above the position where dislocations were generated in four out of the seven ingots. Slices were cut with the pinholes at one surface and etched with Sopori etchant. The pinholes did not appear to have affected the arrangements of etch pits in these samples and investigation of pinholes did not reveal the cause of structure loss. Furthermore, there were not significantly higher pinhole frequency before structure loss compared to ingots without structure loss among 4041 industrial ingots. Modeling of thermal stresses showed stress concentration around a pinhole, and it gives new insight into the level of stress the ingot can endure without generating dislocations and slip.

Background Surveillance is the backbone of infectious diseases control but an outbreak of a new pathogen to a developing country may have devastating consequences given less prepared healthcare systems in such countries. In October 2015, there was a sharp rise of febrile illnesses reported in Dairot Fever Hospital which prompted the general department for fever hospitals in the Egyptian ministry of health (MOH) to constitute a scientific committee for field visit study in Dairot fever hospital. Methods The committee held meetings at Dairot fever hospital, educated local healthcare providers, examined all isolated patients and requested samples of 118 isolated patients to be sent to central laboratories of MOH. Entomological services were also part of the committee and surveillance was started in the affected area. Results Out of 118 samples, 28 came back positive for Dengue virus type 1 by ELISA and PCR. Entomological surveillance revealed the presence of Aedes aegypti larvae and adult mosquito at the sites where cases were living; consequently, entomological control measures for dengue vector were immediately set leading to a dramatic decline in the density of adult mosquito (from 23% to 0%) and larvae (from 25% to 0.5%). Conclusion The prompt response of the MOH in Egypt led to rapid control of Dengue fever outbreak but educating healthcare workers about possible imported infectious diseases would have halted the outbreak much earlier which shows the importance of Infectious Diseases training in developing countries. Disclosures All authors: No reported disclosures.

Statement of problem. Several 1-bottle dentin adhesive resins have been introduced to the market; however, their shear bond strength still requires further investigation. Purpose. This study was designed to evaluate the shear bond strength of five 1-bottle fifth generation dentin adhesive resin materials. Material and methods. Bond 1, Single Bond, One-Step, Prime & Bond 2.1, and Tenure Quick with fluoride were evaluated. Tenure All-Surface Bonding System, a fourth generation dentin adhesive resin, was used as the control group. Twelve specimens were prepared from each material, and the shear bond strength was measured by using a universal testing machine at a crosshead speed of 0.5 mm/min. Fracture patterns were studied with the use of light and SEM. The results were analyzed with the use of ANOVA. Results. The mean shear bond strength for each resin was as follows: Bond 1: 18.36 ± 3.19 MPa; Single Bond: 16.22 ± 2.11 MPa; One-Step: 22.51 ± 3.69 MPa; Prime & Bond: 16.64 ± 3.66 MPa; Tenure Quick: 16.43 ± 3.2 MPa; and Tenure All-Surface Bonding System: 15.06 ± 3.5 MPa. The shear bond strength values of One-Step dentin adhesive resin showed significant differences compared with the other 5 groups ( P P >.1). Eighty percent or more of the specimens for each adhesive failed at the dentin/adhesive interface. An exception was Tenure All-Surface Bonding System in which all specimens failed at the dentin/adhesive interface. Conclusion. The 1-bottle systems tested bond to dentin with a strength similar to that of the control group. In addition, the shear bond strengths of 4 of the 1-bottle systems tested were not significantly different. (J Prosthet Dent 2000;84:408-12.)

This study evaluated the effect of veneering Dicor castable ceramic with Vitadur N and Dicor Plus feldspathic porcelains. A biaxial flexure test was conducted on five groups of specimens (Dicor castable ceramic, Vitadur N dentinal porcelain, Dicor Plus dentinal porcelain, Dicor core veneered with Vitadur N and Dicor core veneered with Dicor Plus castable ceramic). Each group consisted of 10 disks of nearly identical dimensions with a 1.98 ± 0.04 mm thickness and 15.7 ± 0.35 mm in diameter. Statistical analysis indicated that there was neither significant difference ( p > 0.05) between mean flexural strength of Dicor Plus and Vitadur N ceramic or Vitadur N and Dicor/Vitadur N ceramic specimens. The mean flexural strength of Dicor/Vitadur N specimens was significantly lower than the mean flexural strength of Dicor ceramic specimens. Conversely, there was no significant difference between mean flexural strength of Dicor ceramic and Dicor/Dicor Plus ceramic specimens. Scanning electron microscope (SEM) examinations of Dicor/Dicor Plus ceramic specimens suggested better wetting of Dicor core by Dicor Plus ceramic with lower incidence of porosity at the interface. However, Dicor/Vitadur N ceramic specimens exhibited a higher incidence of porosity at the interface. This indicated that lamination of Dicor castable ceramic material with feldspathic porcelain for esthetics could be attained without sacrificing strength of the original material, provided that appropriate veneering material was selected.

Non disponible / Not available, La maîtrise de la formation des microstructures, qui apparaissent lors de la solidification de l'acier coulé en continu, est importante car ces microstructures sont en grande partie responsables de la qualité des produits coulés. Dans cet objectif, la modélisation numérique peut être d'une grande utilité. L'objectif de ce travail est de construire un modèle 2-D de solidification en coulée continue de l'acier en se basant sur un modèle de solidification en lingots déjà disponible. L'approche utilisée consiste à coupler les aspects macroscopiques de transferts thermiques avec les aspects microscopiques de croissances colonnaire et équiaxe. A l'échelle macroscopique, les échanges de chaleur sont calculés par un modèle thermique classique. L'équation de conservation de l'énergie, sans prise en compte de la convection dans les zones liquide et pâteuse, est résolue à l'aide de la méthode des volumes finis, en utilisant la méthode enthalpique. A l'échelle microscopique, le modèle proposé tient compte de la surfusion chimique à la pointe des dendrites colonnaires et équiaxes dont la cinétique de croissance, applicable à un alliage multiconstitué, est contrôlée par la diffusion dans le liquide. La solidification colonnaire est décrite en utilisant un chemin de solidification "tronqué". Pour traiter la solidification équiaxe, un modèle de croissance qui considère une fraction interne de solide variable dans les grains a été utilisé. Pour prédire la position de la transition colonnaire-équiaxe (T.C.E.), un critère de blocage a été introduit. Le modèle a été appliqué à des conditions typiques de coulée-continue et les prédictions des calculs ont été comparées à des mesures expérimentales. Le modèle permet de rendre compte des tendances observées sur l'influence de paramètres tels que la surchauffe et la densité de grains sur la position de la transition.