Simulated and realised industrial yields in sawing of maritime pine (Pinus pinaster Ait.)

A sawing simulation software was evaluated by comparison with a real situation in the industrial sawing of maritime pine (Pinus pinaster Ait.) stems. At an operational sawmill sawing yields were measured for the conversion of logs with two sawing patterns: production of boards and production of boards and lumber. The simulation used the WoodCIM® optimisation software with similar sawing set-ups and dimensionally matching virtual logs obtained from cross cutting of 3D mathematical reconstructions of maritime pine stems. The virtual maritime pine stems and the sawing simulation software showed potential to evaluate the impact of raw material and process characteristics on the production performance. The simulated sawing yields corresponded closely to the industrial yields for the production of boards (57% volume yield). For production of lumber and boards, the simulation allowed to obtain a higher volume (45% vs. 53%). The negative impact of resin production on the sawing yields was estimated by comparing the industrial yields of resin tapped trees with matching virtual logs and showed a loss of 11% sawn wood volume, increasing with log diameter.     

Variants of codes and indecomposable languages

We continue the investigation of representing a language as a catenation of languages, each of which cannot be further decomposed in a nontrivial fashion. We study such prime decompositions, both finite and infinite ones. The notion of a length code, an extension of the notion of a code leads to general results concerning decompositions of star languages. Special emphasis is on the decomposition of regular languages. Also some open problems are mentioned.     

Conformal Hermetic Sealing of Wireless Microelectronic Implantable Chiplets by Multilayered Atomic Layer Deposition (ALD)

A hermetic sealing method of sub‐millimeter‐sized microelectronic chiplets for wireless body implants is presented by ultrathin and electromagnetically transparent atomic layer deposition (ALD) coatings. Fully 3D conformal encapsulation of wirelessly powered microdevices is demonstrated both with and without opening windows for electrophysiological measurements. The chiplets embedding custom application‐specific integrated circuits (ASICs) with radio frequency (RF) transmitters are encapsulated by a stack of alternating layers of hafnium oxide and silicon dioxide to maximize impermeability of water and ionic penetration while minimizing the volume of the packaging material. The hermeticity of the devices is characterized through accelerated aging tests in saline at T = 87 °C, while continued functionality is monitored via evaluation of backscattered RF signals (near 1 GHz) to ascertain possible degradation and electronic failure. Earliest failures of wirelessly functional devices occur after more than 180 d of immersion at 87 °C. Wireless devices having opening windows through the ALD envelope show no signs of degradation for >100 d. This implies an equivalent lifetime >10 years at T = 37 °C. This approach is readily scalable to high throughput batch processing of hundreds of microchiplets, offering a methodology for hermetic packaging of microscale biomedical chronic implants.     

In sweet harmony or in bitter discord? How cultural values and stakeholder requirements shape and users read an urban computing technology

AI & SOCIETY - Culture is, in many ways, implicated in and shapes technology design and use. Inspired by Stuart Hall’s conception of encoding/decoding, we maintain that technological...     

A low noise 0.9 GHz FBAR clock

A low noise 0.9 GHz FBAR clock consisting of an oscillator and divider circuit for single-sided-to-differential conversion for a high-speed interleaved pipeline A/D-converter was designed, realized with an in-house FBAR and a commercial 0.35 μm CMOS process, and tested. The circuit showed very good jitter and phase noise performance. A temperature coefficient of –47 ppm/K was measured.     

Photovoltaic measurement of bandgap narrowing in moderately doped silicon

Solar cells have been fabricated on n-type and p-type moderately doped Si. The shrinkage of the Si bandgap has been obtained by measuring the internal quantum efficiency in the near infrared spectrum (hv = 1.00?1.25 eV) around the fundamental absorption edge. The results agree with previous optical measurements of bandgap narrowing in Si. It is postulated that this optically-determined bandgap narrowing is the rigid shrinkage of the forbidden gap due to many-body effects. The “device bandgap narrowing” obtained by measuring the pn product in bipolar devices leads to discrepant values because (i) the density of states in the conduction and valence band is modified due to the potential fluctuations originated in the variations in local impurity density, and (ii) the influence of Fermi-Dirac statistics.     

On infinite words obtained by iterating morphisms

The paper investigates infinite words, and sets of them, associated with DOL and DTOL systems. Main emphasis is on characterization and decidability results.