Residual Stresses in Layered Manufacturing

Layered Manufacturing processes accumulate residual stresses during materialbuildup. These stresses may cause part warping and layer delamination. This paper presents work done on investigating residual stress accumulation andp(i,rt distortion of Layered Manufactured artifacts. A simple analyticaLmodel was developed and used to determine how the number of layers and the layer thickness influences part warping. Resllits show that thin layers produce lower part deflection as compared with depositing fewer and thicker layers. In addition to the analytical work, a finite element model wasdeveloped and used to illvestigate the deposition pattern's influence on. the part deflection. Finite element model and corresponding experimental analysis showed that the geometry of the deposition pattern significantly affects the resulting part distortion. This finite element model was also used to investigate an inter-layer surface defect,. known as the Christmas Thee Step, that is associated with Shape Deposition Manufacturing. Results indicate that the features of this defect are influenced only by the material deposited close. to the part·surface and the particular material deposited. The step is not affected by the deposition pattern.Mechanical Engineerin

Stable, inflatable life raft for high seas rescue operations

Raft is easily deployed and highly maneuverable in water. It has false bottom of water ballast containers attached to underside, making it exceptionally stable platform from which swimmers can operate. Raft is attachable to external moorings

The information of high-dimensional time-bin encoded photons

We determine the shared information that can be extracted from time-bin entangled photons using frame encoding. We consider photons generated by a general down-conversion source and also model losses, dark counts and the effects of multiple photons within each frame. Furthermore, we describe a procedure for including other imperfections such as after-pulsing, detector dead-times and jitter. The results are illustrated by deriving analytic expressions for the maximum information that can be extracted from high-dimensional time-bin entangled photons generated by a spontaneous parametric down conversion. A key finding is that under realistic conditions and using standard SPAD detectors one can still choose frame size so as to extract over 10 bits per photon. These results are thus useful for experiments on high-dimensional quantum-key distribution system.Comment: 18 pages, 6 figure

Machine learning with the hierarchy‐of‐hypotheses (HoH) approach discovers novel pattern in studies on biological invasions

Research synthesis on simple yet general hypotheses and ideas is challenging in scientific disciplines studying highly context‐dependent systems such as medical, social, and biological sciences. This study shows that machine learning, equation‐free statistical modeling of artificial intelligence, is a promising synthesis tool for discovering novel patterns and the source of controversy in a general hypothesis. We apply a decision tree algorithm, assuming that evidence from various contexts can be adequately integrated in a hierarchically nested structure. As a case study, we analyzed 163 articles that studied a prominent hypothesis in invasion biology, the enemy release hypothesis. We explored if any of the nine attributes that classify each study can differentiate conclusions as classification problem. Results corroborated that machine learning can be useful for research synthesis, as the algorithm could detect patterns that had been already focused in previous narrative reviews. Compared with the previous synthesis study that assessed the same evidence collection based on experts' judgement, the algorithm has newly proposed that the studies focusing on Asian regions mostly supported the hypothesis, suggesting that more detailed investigations in these regions can enhance our understanding of the hypothesis. We suggest that machine learning algorithms can be a promising synthesis tool especially where studies (a) reformulate a general hypothesis from different perspectives, (b) use different methods or variables, or (c) report insufficient information for conducting meta‐analyses

Palynology and Age of the Alvord Creek Formation, Steens Mountain, Southeastern Oregon

The age of the Alvord Creek Formation of Steens Formation, southeastern Oregon, has been a center of controversy since Axelrod\u27s 1944 paleobotanical assignment of a Lower Pliocene age to the tuffaceous leaf-bearing shales. This date varies from earlier determinations by Chaney and MacGinitie that the flora was Mascall (Upper Miocene) equivalent. However, it is more sharply contradicted by the report of a Middle Miocene (Barstovian) fauna in the apparently overlying Steens Basalt and by a 21.3 m.y. radiometric date obtained on a basalt flow 61 meters above the leaf-bearing beds. Palynomorphs recovered from three exposures of the leaf-bearing beds show only a fair to low correspondence at the generic level with the megaflora previously reported by Axelrod and Wolfe. Several new taxa are encountered in the palynoflora including the gymnosperms Tsuga, ?Taxodium, Podocarpus, and Ephedra and the angiosperms Quercus, Ulmus, Corylus, Juglans, Fraxinus, and Nyssa. Pollen assigned to the undivided Taxaceae-Cupressaceae-Taxodiaceae group, Quercus and Abies dominate the assemblage; monolete and trilete spores are conspicuously rare. The overall composition of the palynoflora lends support to Axelrod\u27s Pliocene assignment. The abundance of Abies and other coniferous pollen combined with the lack of ferns and other typical Miocene taxa indicate a cool, dry climate such as is associated with the latest Tertiary. However, a tuff 15-20 cm above the leaf bed yielded a K/Ar date of 23.8 m.y.b.p., lowermost Miocene or even uppermost Oligocene. Stratigraphic relationships in Steens Mountain are obscure and may be complicated by normal or thrust faults, as has been suggested by some structural geologists. There is also the possibility that the K/Ar date determined for the tuff overlying the leaf bearing shales is in error. Whatever the reason(s) for the discrepant age assignments, there is not now a satisfactory resolution to the problem of discordant dating of the Alvord Creek Formation by paleobotanical and radiometric methods

Damping in quantum love affairs

In a series of recent papers we have used an operatorial technique to describe stock markets and, in a different context, {\em love affairs} and their time evolutions. The strategy proposed so far does not allow any dumping effect. In this short note we show how, within the same framework, a strictly non periodic or quasi-periodic effect can be introduced in the model by describing in some details a linear Alice-Bob love relation with damping.Comment: in press in Physica