Toolpath Planning Methodology for Multi-Gantry Fused Filament Fabrication 3D Printing

Additive manufacturing (AM) has revolutionized the way industries manufacture and prototype products. Fused filament fabrication (FFF) is one of the most popular processes in AM as it is inexpensive, requires low maintenance, and has high material utilization. However, the biggest drawback that prevents FFF printing from being widely implemented in large-scale production is the cycle time. The most practical approach is to allow multiple collaborating printheads to work simultaneously on different parts of the same object. However, little research has been introduced to support the aforementioned approach. Hence a new toolpath planning methodology is proposed in this paper. The objectives are to create a collision-free toolpath for each printhead while maintaining the mechanical performance of the printed model. The proposed method utilizes the Tabu Search heuristic and a combination of two subroutines: collision checking and collision resolution (TS-CCR). A computer simulation was used to compare the performance of the proposed method with the industry-standard approach in terms of cycle time. Physical experimentation is conducted to validate the mechanical strength of the TS-CCR specimens. The experiment also validated that the proposed toolpath can be executed on a custom multi-gantry setup without a collision. Experimental results indicated that the proposed TS-CCR can create toolpaths with shorter makespans than the current standard approach while achieving better ultimate tensile strength (UTS). This research represents opportunities for developing general toolpath planning for concurrent 3D printing

Utilizing the Organizational Power of DNA Scaffolds for New Nanophotonic Applications

AbstractRapid development of DNA technology has provided a feasible route to creating nanoscale materials. DNA acts as a self‐assembled nanoscaffold capable of assuming any three‐dimensional shape. The ability to integrate dyes and new optical materials such as quantum dots and plasmonic nanoparticles precisely onto these architectures provides new ways to exploit their near‐ and far‐field interactions. A fundamental understanding of these optical processes will help drive development of next‐generation photonic nanomaterials. This review is focused on latest progress in DNA‐based photonic materials and highlights DNA scaffolds for rapidly assembling and prototyping nanoscale optical devices. Three areas are discussed including intrinsically active DNA structures displaying chiral properties, DNA scaffolds hosting plasmonic nanomaterials, and fluorophore‐labeled DNAs that engage in Förster resonance energy transfer and give rise to complex molecular photonic wires. An explanation of what is desired from these optical processes when harnessed sets the tone for what DNA scaffolds are providing toward each focus. Examples from the literature illustrate current progress along with a discussion of challenges to overcome for further improvements. Opportunities to integrate diverse classes of optically active molecules including light‐generating enzymes, fluorescent proteins, nanoclusters, and metal–chelates in new structural combinations on DNA scaffolds are also highlighted

Enhanced conservation biological control of light brown apple moth in vineyards

The light brown apple moth (LBAM), Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is the most damaging insect pest of wine grapes in Australia. Biological control contributes to the management of LBAM. This project aims to enhance the conservation biological control of LBAM by examining how the provision of alternative hosts and native flowering plants can sustain parasitoids like Dolichogenidea tasmanica (Cameron) (Hymenoptera: Braconidae). Native plants and alternative host insects that could support conservation biological control of LBAM in South Australian vineyards are evaluated. The contribution that D. tasmanica makes to biological control of LBAM would be more reliable if this wasp parasitises common alternative hosts, maintains populations on them when the grapevines are dormant, and then moves to attack LBAM when it reinvades vineyards. This study examined the foraging behaviour of D. tasmanica on LBAM and two tortricid species that are associated with vineyards, Acropolitis rudisana (Walker) and Merophyas divulsana (Walker). The reciprocal responses of these insect hosts were also studied to determine their susceptibility to wasp attack. During behavioural assays, all hosts were accepted by D. tasmanica with high parasitism rates. The parasitoid responded differently to different host species. These experiments indicate that populations of D. tasmanica should be conserved, and LBAM more reliably suppressed, if the alternative hosts, M. divulsana and A. rudisana, are present. Host choice between E. postvittana and M. dilvusana by D. tasmanica was also studied in a wind tunnel, where the wasp could express its natural searching behaviour. Choices tests were conducted to examine how natal hosts, host stages and the wasp’s experiences could affect the landing selections of D. tasmanica. Developmental outcomes of parasitoids on different host species were also examined. D. tasmanica exhibited no clear preference for either host. Host species did not affect the body size of the wasp, but did influence its developmental time, probably as a result of differences in the host’s body sizes. The sex ratio of the wasp did not vary between these host species. These results suggest that M. divulsana is a promising alternative host species to support parasitoid populations in vineyards. A field study was conducted to evaluate the potential impacts of candidate plants on biological control of leafrollers, especially LBAM. Five species were planted beside vineyards to provide shelter, nectar and alternative hosts for beneficial insects. The plants were Bursaria spinosa, Leptospermum lanigerum, Hakea mitchellii, Melaleuca lanceolata and Myoporum petiolatum. Similar leafroller abundances and parasitism rates were found between vineyard rows adjacent to the native plants compared to rows furthest from them. The absence of a difference was possibly due to the proximity of the experimental treatment areas and the movement of parasitoids. The results, including increasing parasitoid diversity over time, imply potential benefits of the plants for better leafroller management. The results from my studies suggest that selected supplementary resources can benefit parasitoids and thereby stabilise or enhance biological control of LBAM in vineyards. This research provides a foundation to develop strategies to better suppress LBAM by facilitating more stable biological control.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 201

Pour un développement respectueux de la ville de Hué et de ses environs : respecter les valeurs caractéristiques des villages traditionnels dans le bassin de la rivière des Parfums

This research focuses on the issues of the respectful development of Hue City and its surroundings, with a specific emphasis on the conservation and the regeneration of qualities, which constitute the peculiarity of this city and surrounding villages. The research is built in the context where the urbanization and the proliferation of new urban areas and new residential neighborhoods led to numerous threats and hazards to the city and resulted in the loss of characteristic values of this area. The hypotheses of the research concern the relationship between conservation, regeneration and sustainable management of heritage, water system and characteristics values of the traditional villages with the environmental development, the economic development, the social and cultural development of this territory. The main corpus used in this thesis is the data mapping GIS 2010 Hue and the ancient maps , these documents, historical works for Hue city and study villages, and interviews, survey questionnaires, photographic records collected during our field survey in Hue. Thanks to the analytical methodology, especially the cartographic analysis and the onsite survey methodology, we can define the specific characteristics of this area and demonstrate the main threats and hazards to the city and the surroundings caused by the urbanization. In this research, we also aim at offering what to do in order to reach a friendly development of the ecological environment, the quality of life and the comfort of local citizens, the potential of the local economy as well as the characteristic values of Hue City and surrounding villages.Ce travail de recherche se concentre sur les questions du développement respectueux de la ville de Hué et de ses environs, en accordant une importance spécifique à la conservation et la mise en valeur des qualités faisant la particularité de cette ville et des villages avoisinants. La recherche est construite dans le contexte où le processus d'urbanisation et la prolifération des nouvelles zones urbaines et des nouveaux quartiers résidentiels ont entraîné de nombreuses menaces et dangers pour cette ville et ont engendré la perte des valeurs caractéristiques de ce territoire. Les hypothèses de la recherche abordent les relations entre la conservation, la mise en valeur et la gestion durable du patrimoine, du système de l'eau et des valeurs caractéristiques des villages d'ores et déjà inscrits dans le développement environnemental, économique, socioculturel de ce territoire. Les corpus principaux utilisés dans cette thèse, sont des données de cartographique GIS Hué 2010 et des cartes anciennes traitées par la l'analyse cartographique et l'analyse comparative des documents, des ouvrages historiques concernant la ville de Hué et des villages d'étude, ainsi que des entretiens, des questionnaires d'enquête, des relevés photographiques récoltés lors de nos séjours d'étude de terrain à Hué. Grâce à la méthodologie d'analyse, surtout l'analyse cartographique et la méthodologie d'enquête de terrain, nous pouvons définir des caractères spécifiques de ce territoire et démontrer des menaces et des dangers principaux pour cette ville et ses environs face aux processus d'urbanisation. Dans la recherche, nous avons également l'ambition de proposer ce qu'il faudrait mettre en œuvre pour un développement respectueux de l'environnement écologique, de la qualité de vie et du bien-être des habitants, des potentiels de l'économie locale, et de même que des valeurs caractéristiques de la ville de Hué et des villages avoisinants

Nanoscale Photonic Devices Fabricated Using DNA Nanostructures

In the field of DNA nanotechnology, self-assembly is being advanced as the key technology for the creation of nanoscale structures. Popular and effective DNA nanotechnology methods of producing nanoscale structures are branched DNA junctions and DNA origami. DNA nanostructures have recently been employed as scaffolds for the bottom-up arrangement of proteins, as well as semiconductor and metallic nanoparticles, with nanometer precision. Such structures are expected to exhibit unique optical properties and may enable new photonic devices. Conversely, the majority of photonic devices for optical waveguide are fabricated using top-down processes. However, the cost and controllability of complex nanostructures using top-down processes imposes significant challenges. As an alternative to top-down processes, work will be presented demonstrating the use of DNA self-assembly processes to fabricate nanoscale photonic devices for optical waveguide. To fabricate photonic devices using DNA self-assembly, DNA nanostructures were used as scaffolds to configure light emitting molecules so as to create a near-field energy transfer waveguide. Spectrophotometry was used to characterize the device operation. The spectral results indicate that DNA nanostructures functionalized with light emitting molecules can transfer energy through a three molecule system with 28% efficiency, demonstrating the potential of using DNA nanostructures for future photonic devices for optical waveguide

Damage detection in structural health monitoring using combination of deep neural networks

Structural Health Monitoring is a process of continuous evaluation of infrastructure status. In order to be able to detect the damage status, data collected from sensors have to be processed to identify the difference between the damaged and the undamaged states. In recent years, convolution neural network has been applied to detect the structural damage and with positive results. This paper proposes a new method of damage detection using combination of deep neural networks. The method uses a convolution neural network to extract deep features in time series and Long Short Term Memory network to find a statistically significant correlation of each lagged features in time series data. These two types of features are combined to increase discrimination ability compared to deep features only. Finally, the fully connected layer will be used to classify the time series into normal and damaged states. The accuracy of damaged detection was tested on a benchmark dataset from Los Alamos National Laboratory and the result shows that hybrid features provided a highly accurate damage identification

Participatory Land Use Planning for Climate-Smart Villages: Guidelines and References

Participatory land-use planning (PLUP) refers to a bottom-up method of analyzing land and water resources. In its current form, PLUP integrates inputs about climate change and sea level rise to help the community utilize the resources within its vicinities. In utilizing its resources, the community will be able to improve the people’s livelihoods and help them sustain such resources for the benefit of the next generations. This publication in implementing PLUP focused on climate-smart adaptation in Climate-Smart Villages (CSVs)

An Analysis of COVID-19 Vaccine Hesitancy in the U.S. at the County Level

Reluctance or refusal to get vaccinated, referred to as vaccine hesitancy (VH), has hindered the efforts of COVID-19 vaccination campaigns. It is important to understand what factors impact VH behavior. This information can help design public health interventions that could potentially increase vaccine uptake. We develop a random forest (RF) classification model that uses a wide variety of data to determine what factors affected VH at the county level during 2021. We consider static factors (such as gender, race, political affiliation, etc.) and dynamic factors (such as Google searches, social media postings, Stringency Index, etc.). Our model found political affiliation and the number of Google searches to be the most relevant factors in determining VH behavior. The RF classification model grouped counties of the U.S. into 5 clusters. VH is lowest in cluster 1 and highest in cluster 5. Most of the people who live in cluster 1 are democrat, are more internet-inquisitive (are more prone to seek information from multiple sources on the internet), have the longest life expectancy, have a college degree, have the highest income per capita, live in metropolitan areas. Most people who live in cluster 5 are republicans, are the least internet-inquisitive, have the shortest life expectancy, do not have a college degree, have the lowest income per capita, and live in non-metropolitan areas. Our model found that counties in cluster 1 were most responsive to vaccination-related policies and COVID-19 restrictions. These strategies did not have an impact on the VH of counties in cluster 5.Comment: 28 pages, 12 figures, 4 table

Inverse kinematic control algorithm for a welding robot - positioner system to trace a 3D complex curve

The welding robots equipped with rotary positioners have been widely used in several manufacturing industries. However, for welding a 3D complex weld seam, a great deal of points should be created to ensure the weld path smooth. This is a boring job and is a great challenge - rotary positioner system since the robot and the positioner must move simultaneously at the same time. Therefore, in this article, a new inverse kinematics solution is proposed to generate the movement codes for a six DOFs welding robot incorporated with a rotary positioner. In the algorithm, the kinematic error is minimized, and the actual welding error is controlled so that it is always less than an allowable limit. It has shown that the proposed algorithm is useful in developing an offline CAD-based programming tool for robots when welding complex 3D paths. The use of the algorithm increases the accuracy of the end-effector positioning and orientation, and reduces the time for teaching a welding robot - positioner system. Simulation scenarios demonstrate the potency of the suggested method