D-Scan Measurement of the Ablation Threshold and Incubation Parameter of Optical Materials in the Ultrafast Regime

AbstractMachining with ultrafast laser pulses demands the selection of correct conditions to obtain precise, and yet, efficient material extraction, in which the control of volume and physical state of the matter being etched is fundamental. Usually, the production of volumetric structures needs overlapping of many pulses, and the incubation effects and its dependence on process parameters are of prime importance. Hence, in this work this parameter and the damage thresholds for many different pulses overlapping were measured for some optical glasses with an alternative method which is faster than the traditional one, and is closer to the real machining condition

Forced marriage among men: An unrecognized problem

Forced marriage is generally viewed as a clash between culture and gender and the fact that men are also victims, in a small number of cases, escapes attention of policy makers and activists. While the overall approach to forced marriage has helped men as well they, however, have remained below the radar of public concern. A problem particular to men is their unwillingness to articulate in public forums their predicament as questions of masculinity are then raised. Ultimately men will have to break the silence, organize and mobilize collectively if they wish to see specific policies that target men

Applications of Raman spectroscopy in dentistry:Analysis of tooth structure

Tooth enamel is the most mineralized tissue in the human body, and in this article the use of Raman spectroscopy for the analysis of tooth structure, a comparison with synthetic apatites, and use in dentistry are described. Spectral peaks that are related to dental hard and soft tissues are discussed, which provide crucial data in understanding the chemical structural properties of dentin and enamel. The Raman spectrum of dentin confirms the presence of crystalline phosphate-based minerals in dentin. Both dentin and enamel consist of two primary components: an inorganic or mineral phase that closely resembles hydroxyapatite and the Raman spectrum of dentin that confirms the presence of crystalline phosphate-based minerals in dentin. Hence, the mineral phase in dentin and enamel may be characterized essentially as nonstoichiometric substituted apatite. The presence of carbonate (A and B type) incorporated in the hydroxyapatite lattice is also confirmed by the presence of spectral bands. The organic phase, which is mainly composed of type I collagen, is confirmed by the spectral bands of amide I and amide II bands, tryptophan, and phenylalanine. Furthermore, these spectral bands associated with organic and inorganic parts of the enamel and dentin are useful in predicting early formation of carries formation. © 2015 Ravikumar Ramakrishnaiah, Ghufran ur Rehman, Santhosh Basavarajappa, Abdulaziz Abdullah Al Khuraif, B. H. Durgesh, Abdul Samad Khan, and Ihtesham ur Rehman