2,811 research outputs found
An early Byzantine alkali glazing tradition? Discussion of P. Armstrong (2020). The earliest glazed ceramics in constantinople: A regional or international phenomenon? Journal of archaeological science: Reports, 29, 102,078
No full textThe suggestion by Armstrong (2020) that the ceramics from the fifth century monastery of St. Lot, Jordan, represent evidence for an early Byzantine alkali glazing tradition is based upon a misinterpretation of an earlier study by Freestone et al. (2001). The St. Lot glazes were unintentional and formed as a result of the reaction of the kiln vapour with the clay ceramic. Evidence for an early Byzantine alkali glazing technology is called into question
Compositional analysis of archaeological glasses
No full textAbstract At CoDaWork'03 we presented work on the analysis of archaeological glass compositional data. Such data typically consist of geochemical compositions involving 10-12 variables and approximates completely compositional data if the main component, silica, is included. We suggested that what has been termed 'crude' principal component analysis (PCA) of standardized data often identified interpretable pattern in the data more readily than analyses based on log-ratio transformed data (LRA). The fundamental problem is that, in LRA, minor oxides with high relative variation, that may not be structure carrying, can dominate an analysis and obscure pattern associated with variables present at higher absolute levels. We investigate this further using subcompositional data relating to archaeological glasses found on Israeli sites. A simple model for glass-making is that it is based on a 'recipe' consisting of two 'ingredients', sand and a source of soda. Our analysis focuses on the sub-composition of components associated with the sand source. A 'crude' PCA of standardized data shows two clear compositional groups that can be interpreted in terms of different recipes being used at different periods, reflected in absolute differences in the composition. LRA analysis can be undertaken either by normalizing the data or defining a 'residual'. In either case, after some 'tuning', these groups are recovered. The results from the normalized LRA are differently interpreted as showing that the source of sand used to make the glass differed. These results are complementary. One relates to the recipe used. The other relates to the composition (and presumed sources) of one of the ingredients. It seems to be axiomatic in some expositions of LRA that statistical analysis of compositional data should focus on relative variation via the use of ratios. Our analysis suggests that absolute differences can also be informative
An investigation into technological change and organisational developments in glass production between the Byzantine and Early Islamic periods (7th-12th centuries) focussing on evidence from Israel
No full textRoman-Byzantine Palestine was a major producer of glass, and while Arab Conquest of the mid-7th century had no initial effect on glass production, around the 9th-10th century a critical technological change occurred with a shift to plant ash flux. This thesis answers several unresolved questions regarding the chronology, reasons for change and origins of the technology. Around 300 glass samples taken from 7th-13th century vessels were analysed by LA-ICP-MS. Vessels were well-contextualised of mainly diagnostic types and sourced from 19 excavated consumption sites across Israel. Four natron and four plant ash groups were identified. Vessel chronology suggested a decline in Palestinian production during the 8th century as evidenced by the appearance of low-soda recipes produced at Bet Eli’ezer, the import of Egypt II glass, and an influx of plant ash glass. Palestinian glass production appears to discontinue by the 9th century, followed by Egyptian production 50-100 years later. Investigation of the potential reasons for the shift to plant ash glass dismissed political instability and climatic change. Instead economic factors were highlighted, such as long-term pressures on natron supply due to competition from other industries, and rising costs due to state control of extraction and the imposition of tariffs during the 9th century. It was demonstrated that rising costs made natron no longer economically viable for glassmaking. Investigations into the origins of plant ash glass technologies suggested no clear link to Sasanian glassmaking practices, concluding that the technology was adopted from already known local practices. A centralised production model continued after the technological change, with raw glass being exported from Tyre to Palestine and elsewhere. Some vessels were also traded, such as wheel-cut bottles of Mesopotamia origin. Smaller compositional types hinted at the emergence of a non-centralised production model in Syria during the Abbasid period, but this was not conclusive
A 23-μW Keyword Spotting IC With Ring-Oscillator-Based Time-Domain Feature Extraction
No full textThis article presents the first keyword spotting (KWS) IC that uses a ring-oscillator-based time-domain processing technique for its analog feature extractor (FEx). Its extensive usage of time-encoding schemes allows the analog audio signal to be processed in a fully time-domain manner except for the voltage-to-time conversion stage of the analog front end. Benefiting from fundamental building blocks based on digital logic gates, it offers better technology scalability compared to conventional voltage-domain designs. Fabricated in a 65-nm CMOS process, the prototyped KWS IC occupies 2.03 mm 2 and dissipates 23- power consumption, including analog FEx and digital neural network classifier. The 16-channel time-domain FEx achieves a 54.89-dB dynamic range for 16-ms frame shift size while consuming 9.3 . The measurement result verifies that the proposed IC performs a 12-class KWS task on the Google Speech Command dataset (GSCD) with >86% accuracy and 12.4-ms latency. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic
A 15-nW per Sensor Interference-Immune Readout IC for Capacitive Touch Sensors
No full textThis paper presents a readout IC that uses an asynchronous capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. A power-efficient tracking algorithm ensures that the CDC consumes negligible power consumption in the absence of touch events. To facilitate its use in wake-on-touch applications, the CDC can be periodically triggered by a co-integrated ultra-low-power relaxation oscillator. At a 38-Hz scan rate, the readout IC consumes 15 nW per touch sensor, which is the lowest reported to date.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Glass production in Late Antiquity and the Early Islamic period: a geochemical perspective
No full textFirst millennium AD glass production was divided between a relatively small number of workshops that made raw glass and a large number of secondary workshops that fabricated vessels. Glass compositions reflect the primary glassmaking source. For most of the period, Egyptian mineral soda was fused with lime-bearing siliceous sand to produce soda-lime-silica glass. The location of the Belus glassmaking sand, which is known from the classical literature, is located on that part of the Levantine coast where iron contents are lowest. Sr-87/Sr-86 of primary glass from workshops in the Levantine region is close to that of modern seawater, and confirms the use of beach sand, which contained shell. Heavy mineral assemblages of Levantine beach sands are dominated by hornblende, hence the primary glasses are characterized by very similar trace element signatures. Glasses believed on archaeological grounds to have been made in other regions, for example in inland Egypt, may have higher Sr-87/Sr-86, reflecting terrigenous sources of lime, and have different trace element signatures. Compositional data for glasses from as far away as Britain suggest origins of the glass material in the Eastern Mediterranean. Recycling of old glass may be recognized by the presence of elevated transition metals. The use of plant ash as a flux became dominant practice in the ninth century and preliminary data for plant ash glasses from the early Islamic world indicate that primary production centres may be separated using strontium and oxygen isotopes as well as by major and trace elements
A 20-bit ±40-mV Range Read-Out IC With 50-nV Offset and 0.04% Gain Error for Bridge Transducers
No full textThis paper presents a 20-b read-out IC with ±40-mV full-scale range that is intended for use with bridge transducers. It consists of a current-feedback instrumentation amplifier (CFIA) followed by a switched-capacitor incremental ΔΣ ADC. The CFIA's offset and 1/ f noise are mitigated by chopping, while its gain accuracy and gain drift are improved by applying dynamic element matching to its input and feedback transconductors. Their mismatch is reduced by a digitally assisted correction loop, which further reduces the CFIA's gain drift. Finally, bulk-biasing and impedance-balancing techniques are used to reduce the common-mode dependency of these transconductors, which would otherwise limit the achievable gain accuracy. The combination of these techniques enables the read-out IC to achieve 140-dB CMRR, a worst-case gain error of 0.04% over a 0-2.5 V common-mode range, a maximum gain drift of 0.7 ppm/°C and an INL of 5 ppm. After applying nested-chopping, the read-out IC achieves 50-nV offset, 6-nV/°C offset drift, a thermal noise floor of 16.2 nV/√Hz and a 0.1-mHz 1/ f noise corner. Implemented in a 0.7-μm CMOS technology, the prototype read-out IC consumes 270 μA from a 5-V supply.Accepted Author ManuscriptElectronic Instrumentatio
A 15nW Per Button Noise-Immune Readout IC for Capacitive Touch Sensor
No full textThis paper presents a readout IC that uses an asynchronous charge-redistribution-based capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. Thanks to the power efficient tracking algorithm, the CDC consumes negligible power consumption in the absence of touch events. To facilitate stand-alone or wake-on-touch applications, the CDC can be periodically triggered by a co-integrated ultra-low power relaxation oscillator. At a 38 Hz scan-rate, the readout IC consumes 15 nW per touch sensor, which is the lowest reported to date.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A 1024-Channel 268 nW/pixel 36x36 μm<sup>2</sup>/ch Data-Compressive Neural Recording IC for High-Bandwidth Brain-Computer Interfaces
No full textThis paper presents a neural recording IC featuring lossy compression during digitization, thus preventing data deluge and enabling a compact active digital pixel design. The wired-OR-based compression discards unwanted baseline samples while allowing the reconstruction of spike samples. The IC features a 32x32 MEA with 36 μ m pixel pitch and consumes 268nW per pixel from a single 1V supply. It achieves 9.8 μ VRMS input-referred noise and 0.3-5kHz bandwidth, resulting in NEF/PEF of 3.7/14.1. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-Electronic
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