A study on the chemical structure of phenyl acetylene radiopolymer

The structure of poly(phenyl acetylene) prepared in bulk, at room temperature by γ‐ray induced polymerization of the monomer (total radiation dose 500 kGy) has been studied by electronic and FTIR spectroscopy and compared to a cis‐rich and a trans‐rich poly(phenyl acetylene). The thermal behaviour has been studied by thermogravimetry (TGA) and by differential thermal analysis (DTA). The polymer is soluble in common solvents and is found to possess low molecular weight, oxygenated end‐groups, and defective structures in the main polymer chain which interrupt and reduce conjugation along the polyenic chain. The simplicity of its preparation opens its use in electronic and optical applications. © 2000 Society of Chemical Industry     

A clock synchronization algorithm for the performance analysis of multicomputer systems

The paper deals with the implementation of global time in multicomputer systems. After a formalization of the synchronization problem, techniques to estimate the synchronization delay and to compensate the drift error are proposed. Then SYNC_WAVE, a clock synchronization algorithm where the values of a reference clock are diffused in a wave-like manner, is described. SYNC_WAVE has no provision for fault-tolerance and is specially designed to introduce low CPU and communication overhead, in order to support performance analysis applications efficiently. An implementation of the devised algorithm in a transputer-based system is presented, showing the accuracy results obtained. Finally SYNC_WAVE is compared to other synchronization algorithms and several of its possible applications are suggested.     

Caulobacter segnis Dioxygenase CsO2: A Practical Biocatalyst for Stilbenoid Ozonolysis

Ozonolysis is a useful as well as dangerous reaction for performing alkene cleavage. On the other hand, enzymes are considered a more sustainable and safer alternative. Among them, Caulobacter segnis dioxygenase (CsO2) known so far for its ability to catalyze the coenzyme-free oxidation of vinylguaiacol into vanillin, was selected and its substrate scope evaluated towards diverse natural and synthetic stilbenoids. Under optimized conditions, CsO2 catalyzed the oxidative cleavage of the C=C double bonds of various trans-stilbenes, providing that a hydroxyl moiety was necessary in para-position of the phenyl group (e. g., resveratrol and its derivatives) for the reaction to take place, which was confirmed by modelling studies. The reactions occurred rapidly (0.5–3 h) with high conversions (95–99 %) and without formation of by-products. The resveratrol biotransformation was carried out on 50–mL scale thus confirming the feasibility of the biocatalytic system as a preparative method.     

Multi-objective optimization of the maritime cargo routing and scheduling problem

This paper addresses the multi-objective maritime cargo routing and scheduling problem, in which the delivery of bulk products from pickup to delivery ports is served by a heterogeneous fleet of vessels. A mixed integer linear programming (MILP) model is formulated to simultaneously minimize total operation costs, the scheduling makespan, and delays in selected deliveries. The model accounts for several real features, such as time windows, capacity of the vessel's compartments, and ports requirements. A fuzzy weighted max–min method was applied to solve the problem. Two heuristics were developed to effectively handle the complex generated MILP models during the solution process. Experiments were conducted to evaluate the optimization approach using real-life instances provided by a fertilizer company. Finally, a case study shows that the developed model and algorithmic framework are flexible and effective in coping with real problems, incorporating specific business rules from different companies.     

Paper-Based Printed Antenna: Investigation of Process-Induced and Climatic-Induced Performance Variability

Printing technologies have emerged as a viable method for the fabrication of various electronic components, including sensors, actuators, energy harvesters, thin-film transistors and circuits, as well as antennas. However, printing processes have limitations in terms of surface roughness and thickness. Printing conductive structures on novel substrates, such as cellulose-based sustainable paper, also leads to further challenges linked to the high surface porosity and ink carrier absorption. Herein, the variability of paper-based printed antenna performance due to different printing processes, ink carrier absorption, and temperature is investigated. The resonance frequency and gain of different printed antennas (e.g., screen, inkjet, and dispense-printed) are compared in terms of surface roughness, thickness, and resonance frequency. Screen-printed antennas show better performance compared to other printed antennas. The results show that the resonance frequency of antenna shifts 20, 30, and 50 MHz for screen printed, dispense printed, and inkjet printed respectively, from the nominal 2.6 GHz. In the case of the inkjet-printed antenna, a clear effect of skin depth is observed, due to the 0.91 $\text{μm}$ thickness. Furthermore, it is demonstrated that the permittivity/dielectric constant of the paper substrate is significantly influenced by ink carrier absorption and temperature variance.     

Laser-Induced,Green and Biocompatible Paper-Based Devices for Circular Electronics

The growing usage and consumption of electronics-integrated items into the daily routine has raised concerns on the disposal and proper recycling of these components. Here, a fully sustainable and green technology for the fabrication of different electronics on fruit-waste derived paper substrate, is reported. The process relies on the carbonization of the topmost surface of different cellulose-based substrates, derived from apple-, kiwi-, and grape-based processes, by a CO₂ laser. By optimizing the lasing parameters, electronic devices, such as capacitors, biosensors, and electrodes for food monitoring as well as heart and respiration activity analysis, are realized. Biocompatibility tests on fruit-based cellulose reveal no shortcoming for on-skin applications. The employment of such natural and plastic-free substrate allows twofold strategies for electronics recycling. As a first approach, device dissolution is achieved at room temperature within 40 days, revealing transient behavior in natural solution and leaving no harmful residuals. Alternatively, the cellulose-based electronics is reintroduced in nature, as possible support for plant seeding and growth or even soil amendment. These results demonstrate the realization of green, low-cost and circular electronics, with possible applications in smart agriculture and the Internet-of-Thing, with no waste creation and zero or even positive impact on the ecosystem.     

Alumina Nanoparticle Interfacial Buffer Layer for Low-Bandgap Lead-Tin Perovskite Solar Cells

Mixed lead-tin (Pb:Sn) halide perovskites are promising absorbers with narrow-bandgaps (1.25–1.4 eV) suitable for high-efficiency all-perovskite tandem solar cells. However, solution processing of optimally thick Pb:Sn perovskite films is notoriously difficult in comparison with their neat-Pb counterparts. This is partly due to the rapid crystallization of Sn-based perovskites, resulting in films that have a high degree of roughness. Rougher films are harder to coat conformally with subsequent layers using solution-based processing techniques leading to contact between the absorber and the top metal electrode in completed devices, resulting in a loss of V_OC, fill factor, efficiency, and stability. Herein, this study employs a non-continuous layer of alumina nanoparticles distributed on the surface of rough Pb:Sn perovskite films. Using this approach, the conformality of the subsequent electron-transport layer, which is only tens of nanometres in thickness is improved. The overall maximum-power-point-tracked efficiency improves by 65% and the steady-state V_OC improves by 28%. Application of the alumina nanoparticles as an interfacial buffer layer also results in highly reproducible Pb:Sn solar cell devices while simultaneously improving device stability at 65 °C under full spectrum simulated solar irradiance. Aged devices show a six-fold improvement in stability over pristine Pb:Sn devices, increasing their lifetime to 120 h.     

A Green Electrically Conductive Textile with Tunable Piezoresistivity and Transiency

A green textile-based conductor with controllable electrical resistance change with deformation and transiency (i.e., dissolution in water) will be the holy grail in wearable electronics since it can satisfy divergent needs with a single solution and be sustainable simultaneously. Nevertheless, designing such material is challenging since opposite requirements shall be satisfied. To solve such a problem, cotton is functionalized using conductive inks made of graphene or carbon nanofiber, a biodegradable polyvinyl alcohol binder, and environmentally friendly solvents. The electrical resistance shows an anisotropic response to bending depending on the composition of the coating and the stress direction, functioning either as a deformable compliant electrode or a tunable piezoresistor. Indeed, it can withstand thousands of bending cycles with a change in resistance of less than 5% or change its resistance by many orders of magnitude with the same deformation thanks to the combination of cotton twill and different nanofillers. A simple modification in the binder composition adding waterborne polyurethane allows the coating to go from entirely transient in water within minutes to withstanding simulated washing cycles for hours without losing its electrical conductivity. This green versatile conductor may serve opposing needs by altering the material composition and the deformation direction.     

Roboat III: An autonomous surface vessel for urban transportation

In this paper, we present our novel autonomous surface vessel platform, a full-scale Roboat for urban transportation. This 4-m-long Roboat is designed with six seats and can carry a payload of up to 1000 kg. Roboat has two main thrusters for cruising and two tunnel thrusters to accommodate docking and interconnectivity between Roboats. We build an adaptive nonlinear model predictive controller for trajectory tracking to account for payload changes while transporting passengers. We use a sparse directed graph to represent the canal topological map and then find the most time-efficient global path in a city-scale environment using the $A^{*}$ algorithm. We then employ a multiobjective algorithm's lexicographic search to generate an obstacle-free path using a point-cloud projected two-dimensional occupancy grid map. We also develop a docking mechanism to allow Roboat to “grasp” the docking station. Extensive experiments in Amsterdam waterways demonstrate that Roboat can (1) successfully track the optimal trajectories generated by the planner with varying numbers of passengers on board; (2) autonomously dock to the station without human intervention; (3) execute an autonomous water taxi task where it docks to pick up passengers, drive passengers to the destination while planning its path to avoid obstacles, and finally dock to drop off passengers.