Cooperative caging and transport using autonomous aquatic surface vehicles

We present a study on the cooperative control of two autonomous surface vehicles performing a caging and transport mission on the water surface. The two vehicles, connected to each other by means of a floating flexible rope, are required to capture a floating target from a given location, and transport it to a designated position. We focus on the coordination and control strategy to meet these requirements, and on its implementation on two under-actuated vehicles. We describe a multi-layered control architecture which achieves the goal, followed by simulation studies and field experiments with the two vehicles caging and transporting a floating target on the surface of a lake.     

Iodine‐Mediated Copper‐Catalyzed Efficient α‐C(sp2)‐Thiomethylation of α‐Oxoketene Dithioacetals with Dimethyl Sulfoxide in One Pot

The direct α‐Csp² H functionalization and thiomethylation of α‐oxoketene dithioacetals (DTAs) has been accomplished with dimethyl sulfoxide (DMSO) in the presence of iodine and a copper(I) salt for the first time. A prerequisite is the in situ iodination of the α‐Csp² atom of dithioacetals that could offer other reaction channels. The operationally simple one‐pot protocol includes region‐defined consecutive iodination and sulfenylation of the challenging α‐Csp² H bond of dithioacetals employing cheap and readily available reagents. DMSO here plays a dual role as thiomethyl source and solvent.

     

A novel image fusion framework for night-vision navigation and surveillance

The night-vision image fusion plays a critical role in detecting targets and obstructions in low light or total darkness, which has great importance for pedestrian recognition, vehicle navigation, surveillance and monitoring applications. The central idea is to fuse low-light visible and infrared imagery into a single output. In this paper, we describe a new fusion framework for spatially registered visual and infrared images. The proposed framework utilizes the properties of fractal dimension and phase congruency in the non-subsampled contourlet transform (NSCT) domain. The proposed framework applies multiscale NSCT on visual and IR images to get low- and high-frequency bands. The varied frequency bands of the transformed images are then fused while exploiting their characteristics. Finally, the inverse NSCT is performed to get the fused image. The performance of the proposed framework is validated by extensive experiments on different scene imaginary, where the definite advantages are demonstrated subjectively and objectively.     

Shear velocity-based uncertainty quantification for rock joint shear strength

Bulletin of Engineering Geology and the Environment - The shear strength of rock joints is an important property required in order to analyze the stability of rock slopes and tunnels. However,...     

Geometrical Variability Impact on the Performance of Sub - 3 nm Gate-All-Around Stacked Nanosheet FET

Silicon - To meet the scaling targets and continue with Moore’s Law, the transition from FinFET to Gate-All-Around (GAA) nanosheet Field Effect Transistors (FETs) is the necessity for...     

Ag2O–Al2O3–ZrO2 Trimetallic Nanocatalyst for High Performance Photodegradation of Nicosulfuron Herbicide

Topics in Catalysis - In the present study, Ag2O–Al2O3–ZrO2 based trimetallic oxide nanocatalyst was designed using simple microwave assisted reduction method. It was characterized...     

Texture modeling in carbon-carbon composites based on mesophase precursor matrices

A computational modeling study of texture formation in carbon-carbon composites based on carbon fibers and carbonaceous mesophase precursors is presented. The modeling predictions on texture formation and disclination structures are quantitatively validated with extensive experimental data. The number and type of disclinations displayed by the carbonaceous mesophase matrix is shown to be governed by the elasticity of the mesophase, the carbon fiber-mesophase interfacial energy, the size of the fibers, and positional arrangement of the fibers. The simulations provide new insights on the fundamental principles that govern texturing and disclination nucleation, and on how to control the structure of carbon-carbon composites through fiber concentration, fiber cross-section, and fiber-matrix interaction.     

RFID-enabled item-level product information revelation

We consider a homogeneous product market and the incentive for oligopolists to share item-level product information with their customers. Enabled by Radio Frequency Identification technology, each firm has the option to record and reveal item-level information of a proportion of its products. We consider a two-stage game where each firm first decides its production plan and then determines its level of information revelation. With a constant clearance discount rate, we derive pure strategy equilibria that are subgame perfect and demonstrate that complete information sharing is the unique Nash equilibrium for the game when the common demand is volatile and that no information revelation is the unique Nash equilibrium when demand is not volatile. Furthermore, we show that the Nash equilibrium is the same with a decreasing clearance discount rate and that neither complete information revelation nor zero information revelation is consistent with an equilibrium with an increasing discount rate. Results are similar in a duopoly non-homogeneous product market scenario.     

Thermodynamic models for vapor-liquid equilibria of nitrogen + oxygen + carbon dioxide at low temperatures

For the design and optimization of CO₂ recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry’s law constants, are proposed for the ternary mixture N₂ + O₂ + CO₂. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry’s law constants of N₂ and O₂ in CO₂ are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry’s law constants, is developed to reliably describe the VLE in the CO₂-rich region.     

Study of the microbial diversity and antimicrobial properties of Irish edible brown seaweeds

Brown Irish edible seaweeds, Himanthalia elongata, Laminaria sachharina and Laminaria digitata, were evaluated for the microbiota in raw and heat processed form. Raw seaweeds showed complete absence of aerobic mesophiles, halophiles, yeasts and molds. However, heating at 85 °C for 15 min resulted in spore germination. Bacterial counts as high as 10⁷ were observed for aerobic mesophiles and halophiles. Heating above 95 °C for 15 min resulted in complete inactivation of surface microflora. Bacteria belonging to Bacillaceae, Paenibacillaceae, Moraxellaceae and Enterobacteriaceae family were identified by 16S rRNA sequencing. In vitro antimicrobial activity of the methanolic extracts of the seaweed on food pathogenic and food spoilage bacteria were also evaluated. The seaweeds in their raw state had almost 100% inhibition against Listeria monocytogenes; 98% and 93% inhibition was achieved against Pseudomonas aeruginosa by H. elongata and L. saccharina extracts, respectively. Heating the seaweeds resulted in the reduction of antimicrobial activity as compared to raw. The effect was more pronounced against Gram negative bacteria.