Unified Software for Multi-Functional G-Code: A Method for Implementing Multi-Technology Additive Manufacturing

Additive manufacturing (AM) began a manufacturing revolution moving industrial production into consumer homes. With interest shifting toward multi-functional parts fabricated through AM technologies, multi-functional fabrication systems are now being developed. Merging different manufacturing technologies into a single machine is a challenge, but ongoing research in the development of multi-technology systems has shown promise. The software and automation aspects of multi-technology systems are being developed in unison. This paper explores the challenges and approaches to developing software that interfaces with multifunctional CADs and creates files for direct use in multi-technology AM machines.Mechanical Engineerin

Nanotailoring Stereolithography Resins for Unique Applications using Carbon Nanotubes

Nanostructured materials and exploiting their properties in stereolithography (SL) may open new markets for unique rapidly manufactured functional devices. Controlled amounts of multiwalled carbon nanotubes (MWCNTs) were successfully dispersed in SL epoxy-based resins and complex three-dimensional (3D) parts were successfully fabricated by means of a multi-material SL setup. The effect of the nanosized filler was evaluated using mechanical testing. Small dispersions of MWCNTs resulted in significant effects on the physical properties of the polymerized resin. A MWCNT concentration of .05 wt% (w/v) in DSM Somos® WaterShed™ 11120 resin increased the ultimate tensile stress and fracture stress an average of 17% and 37%, respectively. Electron microscopy was used to examine the morphology of the nanocomposite and results showed affinity between the MWCNTs and SL resin and identified buckled nanotubes that illustrated strong interfacial bonding. These improved physical properties may provide opportunities for using nanocomposite SL resins in end-use applications. Varying types and concentrations of nanomaterials can be used to tailor existing SL resins for particular applications.Mechanical Engineerin

Formal Verification of Neural Network Controlled Autonomous Systems

In this paper, we consider the problem of formally verifying the safety of an autonomous robot equipped with a Neural Network (NN) controller that processes LiDAR images to produce control actions. Given a workspace that is characterized by a set of polytopic obstacles, our objective is to compute the set of safe initial conditions such that a robot trajectory starting from these initial conditions is guaranteed to avoid the obstacles. Our approach is to construct a finite state abstraction of the system and use standard reachability analysis over the finite state abstraction to compute the set of the safe initial states. The first technical problem in computing the finite state abstraction is to mathematically model the imaging function that maps the robot position to the LiDAR image. To that end, we introduce the notion of imaging-adapted sets as partitions of the workspace in which the imaging function is guaranteed to be affine. We develop a polynomial-time algorithm to partition the workspace into imaging-adapted sets along with computing the corresponding affine imaging functions. Given this workspace partitioning, a discrete-time linear dynamics of the robot, and a pre-trained NN controller with Rectified Linear Unit (ReLU) nonlinearity, the second technical challenge is to analyze the behavior of the neural network. To that end, we utilize a Satisfiability Modulo Convex (SMC) encoding to enumerate all the possible segments of different ReLUs. SMC solvers then use a Boolean satisfiability solver and a convex programming solver and decompose the problem into smaller subproblems. To accelerate this process, we develop a pre-processing algorithm that could rapidly prune the space feasible ReLU segments. Finally, we demonstrate the efficiency of the proposed algorithms using numerical simulations with increasing complexity of the neural network controller

A VLT/VIMOS view of two PlanckPlanck multiple-cluster systems: structure and galaxy properties

We analysed spectroscopic data obtained with VLT-VIMOS for two multiple-cluster systems, PLCKG$214.6+36.9$ and PLCKG$334.8-38.0$, discovered via their thermal Sunyaev-Zel'dovich signal by $Planck$. Combining the Optical spectroscopy, for the redshift determination, and photometric data from galaxy surveys (SDSS, WISE, DESI), we were able to study the structure of the two multiple-cluster systems, to determine their nature and the properties of their member galaxies. We found that the two systems are populated mainly with passive galaxies and that PLCKG$214.6+36.9$ consists of a pair of clusters at redshift $z = 0.445$ and a background isolated cluster at $z = 0.498$, whereas the system PLCKG$334.8-38.0$ is a chance association of three independent clusters at redshifts $z = 0.367$, $z =0.292$, and $z = 0.33$. We also find evidence for remaining star formation activity in the highest-redshift cluster of PLCKG$214.6+36.9$, at $z = 0.498$.Comment: 12 pages, 9 Figures, 5 Tables. Submitted to A&A, comments are welcom

Study of Different Aging Conditions for Analysis of Microstructure and Mechanical Properties of F357 Alloy Fabricated in LPBF Printer

Aluminum F357 is a widely used material for casting in aerospace and additive manufacturing industry. Heat treatments are commonly applied to some aluminum alloys to modify its properties. With a further study on the aging and performance of the F357 with 3D printing technology, several industries benefit of this, military, automotive and aerospace are some examples, because the numerous components casted in service. This work presents mechanical properties of F357 specimens fabricated with EOS technology and subjected to heat treatments. Heat treatments conditions were applied to tensile specimens and tested. Furthermore, the specimens were subjected to artificial thermal aging for 100 h and 1000 h at two different temperatures (285 ºF and 350 ºF), and their mechanical properties were also determined. Finally, remarks on the comparison between the heat treatments and the effect of thermal aging on the microstructures and mechanical properties of the specimens will be presented.Mechanical Engineerin

3D Printing Multi-Functionality: Embedded RF Antennas and Components

Significant research and press has recently focused on the fabrication freedom of Additive Manufacturing (AM) to create both conceptual models and final end-use products. This flexibility allows design modifications to be immediately reflected in 3D printed structures, creating new paradigms within the manufacturing process. 3D printed products will inevitably be fabricated locally, with unit-level customization, optimized to unique mission requirements. However, for the technology to be universally adopted, the processes must be enhanced to incorporate additional technologies; such as electronics, actuation, and electromagnetics. Recently, a novel 3D printing platform, Multi3D manufacturing, was funded by the presidential initiative for revitalizing manufacturing in the USA using 3D printing (America Makes - also known as the National Additive Manufacturing Innovation Institute). The Multi3D system specifically targets 3D printed electronics in arbitrary form; and building upon the potential of this system, this paper describes RF antennas and components fabricated through the integration of material extrusion 3D printing with embedded wire, mesh, and RF elements

Genome-enabled phylogeographic investigation of the quarantine pathogen Ralstonia solanacearum race 3 biovar 2 and screening for sources of resistance against its core effectors.

Phylogeographic studies inform about routes of pathogen dissemination and are instrumental for improving import/export controls. Genomes of seventeen isolates of the bacterial wilt and potato brown rot pathogen Ralstonia solanacearum race 3 biovar 2 (R3bv2), a select agent in the USA, were thus analyzed to get insight into the phylogeography of this pathogen. Thirteen of fourteen isolates from Europe, Africa, and Asia were found to belong to a single clonal lineage while isolates from South America were genetically diverse and carried ancestral alleles at the analyzed genomic loci consistent with a South American origin of R3bv2. The R3bv2 isolates share a core repertoire of thirty-one type III-secreted effector genes representing excellent candidates to be targeted with resistance genes in breeding programs to develop durable disease resistance. Towards this goal, 27 R3bv2 effectors were tested in eggplant, tomato, pepper, tobacco, and lettuce for induction of a hypersensitive-like response indicative of recognition by cognate resistance receptors. Fifteen effectors, eight of them core effectors, triggered a response in one or more plant species. These genotypes may harbor resistance genes that could be identified and mapped, cloned and expressed in tomato or potato, for which sources of genetic resistance to R3bv2 are extremely limited.National Science Foundatio

"Kultur" als Form symbolischer Gewalt: Grenzziehungsprozesse im Kontext von Migration am Beispiel der Schweiz

Die Schweiz gilt international als Modell eines gelungenen Multikulturalismus, dann nämlich wenn es das Zusammenleben der vier Sprachgruppen (Romands, DeutschschweizerInnen, TessinerInnen, RäteromanInnen) betrifft. Ein sprachlicher wie auch religiöser Pluralismus ist und war stets ein Grundbaustein des Selbstverständnisses der „Willensnation“ Schweiz. Geht es aber um MigrantInnen präsentiert sich die Geschichte anders, denn in diesem Falle erscheinen religiöse und ethnisch-kulturelle Pluralität vorwiegend als problematisch. MigrantInnen gehören entsprechend den öffentlichen und politischen Diskursen nicht zum multikulturellen Staat, vielmehr sind Prozesse kollektiver Grenzziehungen und damit Schließungsmechanismen zu beobachten, in denen Ethnizität, Religion und Kultur zu den wichtigsten Differenzierungsmerkmale werden, wie Gemeinsamkeiten gegen innen (SchweizerInnen) und Barrieren gegen außen (Ausländer, Migranten, Muslims, etc.) hergestellt werden. Ich argumentiere in diesem Kapitel, dass sich dieser „Kulturdiskurs“ im letzten Jahrzehnt verstärkt hat und gleichzeitig semantischen Verschiebungen unterworfen war. Mittels der Grenzziehungsperspektive wird historisch nachvollzogen, wie Zuwanderung und Integration in politischen Debatten und Gesetz zunehmend kulturalisiert und ethnisiert wurden. Ein Fallbeispiel aus der Forschung dient mir anschließend der Veranschaulichung dieser theoretischen Perspektive und dieses „neuen“ Essentialismus

EFFECTS OF DIFFERENT PARAMETERS ON DED HR-1 ON LOW CYCLE FATIGUE, TENSILE STRENGTH, AND MICROSTRUCTURE

NASA HR1 alloy is an iron-nickel based material designed by NASA and derived from A286 and JBK-75 alloys. At extreme conditions, NASA HR1 possess high strength, high fatigue resistance, and high resistance to corrosion and hydrogen embrittlement. The main applications include structural components and liquid rocket engine nozzles with internal cooling channels. NASA has produced HR1 using vacuum induction melting (VIM), a considerably expensive fabrication method. Aimed to explore other more affordable and accessible manufacturing methods, HR1 specimens were fabricated under different parameters using Laser-Powder Directed Energy Deposition (LP-DED) and were heat treated through stress relief, homogenization, solution treatment and aging. The feasibility of this AM process was investigated by evaluating mechanical and microstructural analysis on specimens. This work finalizes with discussion and remarks on tensile and low-cycle fatigue properties and its relationship with microstructural features.Mechanical Engineerin