Microdrilling of Biocompatible Materials

This research studies microdrilling of biocompatible materials including commercially pure titanium, 316L stainless steel, polyether ether ketone (PEEK) and aluminum 6061-T6. A microdrilling technique that uses progressive pecking and micromist coolant is developed that allows drilling of 127 micrometers diameter microholes with an aspect ratio of 10:1. The drilling parameters, dominant wear pattern, hole positioning accuracy and effect of AlTiN tool coating are experimentally determined. The experimental data trend agrees with classical Taylor's machining equation. Despite of fragile and long microdrills, the progressive pecking cycle and micromist allowed deep hole drilling on all the tested materials. Drill wear is more pronounced at outer cutting edge due to higher cutting speeds. However, when drilling 316L stainless steel attrition wear at chisel edge is dominant. Hole quality degradation due to formation of built up edge at the drill tip is observed. Coated drill improves tool life by 122% and enhances hole quality when drilling 316L stainless steel. The hole positioning accuracy is improved by 115% and total hole diameter variation decreased from 0.11% to 0.003% per mm of drilling distance

Micromachining

To present their work in the field of micromachining, researchers from distant parts of the world have joined their efforts and contributed their ideas according to their interest and engagement. Their articles will give you the opportunity to understand the concepts of micromachining of advanced materials. Surface texturing using pico- and femto-second laser micromachining is presented, as well as the silicon-based micromachining process for flexible electronics. You can learn about the CMOS compatible wet bulk micromachining process for MEMS applications and the physical process and plasma parameters in a radio frequency hybrid plasma system for thin-film production with ion assistance. Last but not least, study on the specific coefficient in the micromachining process and multiscale simulation of influence of surface defects on nanoindentation using quasi-continuum method provides us with an insight in modelling and the simulation of micromachining processes. The editors hope that this book will allow both professionals and readers not involved in the immediate field to understand and enjoy the topic

Experimental and numerical investigations of bone drilling for the indication of bone quality during orthopaedic surgery

Bone drilling is an essential part of many orthopaedic surgical procedures, including those for internal fixation and for attaching prosthetics. Drilling into bone is a fundamental skill that can be both very simple, such as drilling through long bones, or very difficult, such as drilling through the vertebral pedicles where incorrectly drilled holes can result in nerve damage, vascular damage or fractured pedicles. Also large forces experienced during bone drilling may promote crack formation and can result in drill overrun, causing considerable damage to surrounding tissues. Therefore, it is important to understand the effect of bone material quality on the bone drilling forces to select favourable drilling conditions, and improve orthopaedic procedures. [Continues.

Classification of rock according to its mechanical properties

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A Review and Analysis of Automatic Optical Inspection and Quality Monitoring Methods in Electronics Industry

Electronics industry is one of the fastest evolving, innovative, and most competitive industries. In order to meet the high consumption demands on electronics components, quality standards of the products must be well-maintained. Automatic optical inspection (AOI) is one of the non-destructive techniques used in quality inspection of various products. This technique is considered robust and can replace human inspectors who are subjected to dull and fatigue in performing inspection tasks. A fully automated optical inspection system consists of hardware and software setups. Hardware setup include image sensor and illumination settings and is responsible to acquire the digital image, while the software part implements an inspection algorithm to extract the features of the acquired images and classify them into defected and non-defected based on the user requirements. A sorting mechanism can be used to separate the defective products from the good ones. This article provides a comprehensive review of the various AOI systems used in electronics, micro-electronics, and opto-electronics industries. In this review the defects of the commonly inspected electronic components, such as semiconductor wafers, flat panel displays, printed circuit boards and light emitting diodes, are first explained. Hardware setups used in acquiring images are then discussed in terms of the camera and lighting source selection and configuration. The inspection algorithms used for detecting the defects in the electronic components are discussed in terms of the preprocessing, feature extraction and classification tools used for this purpose. Recent articles that used deep learning algorithms are also reviewed. The article concludes by highlighting the current trends and possible future research directions.Framework of the IQONIC Project; European Union’s Horizon 2020 Research and Innovation Program

The Early Neolithic of the Eastern Fertile Crescent

The Eastern Fertile Crescent region of western Iran and eastern Iraq hosted major developments in the transition from hunter-forager to farmer-herder lifestyles through the Early Neolithic period, 10,000-7000 BC. Within the scope of the Central Zagros Archaeological Project, excavations have been conducted since 2012 at two Early Neolithic sites in the Kurdistan region of Iraq: Bestansur and Shimshara. Bestansur represents an early stage in the transition to sedentary, farming life, where the inhabitants pursued a mixed strategy of hunting, foraging, herding and cultivating, maximizing the new opportunities afforded by the warmer, wetter climate of the Early Holocene. They also constructed substantial buildings of mudbrick, including a major building with a minimum of 65 human individuals, mainly infants, buried under its floor in association with hundreds of beads. These human remains provide new insights into mortuary practices, demography, diet and disease

The Effect of Pressure on Ion Track Formation in Minerals

In many dielectrics, energetic heavy ions produce thin cylindrical damage zones along their trajectories. Massive physical and chemical changes can occur in these ion tracks with diameters of several nm. In nature, such trails are generated by spontaneous fission of 238U-nuclei. So far, irradiation experiments with heavy ions were always performed under vacuum conditions. Studies of ion-track formation in pressurized solids are expected to contribute to an improved understanding of the creation conditions for fission tracks in the Earth�s crust. Such experiments will be important for dating of geological samples using the fission-track technique. In addition, it is a question of great interest whether the energy deposition of swift heavy ions in a solid, being exposed to extreme pressure, can induce specific phase transitions. This work describes the first experiments on ion track formation under high pressures up to 140 kbar which were performed at GSI by injecting relativistic heavy ions, accelerated with the SIS-heavy-ion synchrotron, through the diamond anvils of a high-pressure cell. It turned out that high pressures can significantly affect the interaction between heavy ions and solids. The effects observed include the suppression of track formation, the complete recrystallization, and the nucleation of new phases

The ideological significance of flint in Dynastic Egypt

This thesis examines a little understood aspect of Dynastic Egypt—that of the ideology of flint. Ideology is defined as the way flint is thought of rather than used. This study is unique in examining long term chronological changes in flint ideology against the background of increased metal use, and in using together text, iconography, and archaeology: studies of Egyptian ideology traditionally privilege text. Metaphor theory is employed as an important tool to aid this study. While metaphor is frequently used in Egyptological studies of Egyptian religion, its use is rarely explicit. The dataset brings together unpublished artefacts in British museum collections; a first hand analysis of lithics from Panhesy’s house at Amarna; finds cards from recent excavations at Memphis; and textual sources, several of which have not been considered before in relation to the ideology of flint; as well as published data on Egyptian lithic material. Chronological changes in ideology surrounding flint during the Bronze and Iron Ages, a time of flint decline, are considered. Because the nature of flint decline in Egypt has been assumed rather than known, I attempt to quantify the process. Conclusions show that the ideology of flint was far from static but only loosely related to the kinetic decline of flint. Flint is shown to be connected with the goddesses who are the Eye of Re, with Re himself, with snakes and lions. New facets of flint ideology are uncovered, including the connection of the material with the northern sky and the link between the treatment of New Kingdom Theban flint concretions and the religious landscape of the area

Prediction of microdrill breakage using rough sets

This study attempts to correlate the nonlinear invariants' with the changing conditions of a drilling process through a series of condition monitoring experiments on small diameter (1 mm) drill bits. Run-to-failure tests are performed on these drill bits, and vibration data are consecutively gathered at equal time intervals. Nonlinear invariants, such as the Kolmogorov entropy and correlation dimension, and statistical parameters are calculated based on the corresponding conditions of the drill bits. By intervariations of these values between two successive measurements, a drop–rise table is created. Any variation that is within a certain threshold (±20% of the measurements in this case) is assumed to be constant. Any fluctuation above or below is assumed to be either a rise or a drop. The reduct and conflict tables then help eliminate incongruous and redundant data by the use of rough sets (RSs). Inconsistent data, which by definition is the boundary region, are classified through certainty and coverage factors. By handling inconsistencies and redundancies, 11 rules are extracted from 39 experiments, representing the underlying rules. Then 22 new experiments are used to check the validity of the rule space. The RS decision frame performs best at predicting no failure cases. It is believed that RSs are superior in dealing with real-life data over fuzzy set logic in that actual measured data are never as consistent as here and may dominate the monitoring of the manufacturing processes as it becomes more widespread.Journal ArticleAA