Smart water technology for leakage detection: feedback of large-scale experimentation

Recent advances in intelligent water meter technology have improved the quantitative monitoring in water supply and distribution systems. Smart meters using automated meter reading (AMR) technology allow water utilities to: (a) provide clear consumption patterns which can help customers to track and control their water usage and (b) improve active leakage targeting and leak detection capability. This paper presents a feedback about the use of AMR system to detect leakage in a large-scale experimentation, which is conducted at the Scientific Campus of the University of Lille, which stands for a small town of 25,000 users. This paper presents the demonstration site as well as its monitoring using AMR technology and how this technology allowed a rapid detection of water leakage.     

Intra-Operative Bioprinting of Hard,Soft, and Hard/Soft Composite Tissues for Craniomaxillofacial Reconstruction

Reconstruction of complex craniomaxillofacial (CMF) defects is challenging due to the highly organized layering of multiple tissue types. Such compartmentalization necessitates the precise and effective use of cells and other biologics to recapitulate the native tissue anatomy. In this study, intra-operative bioprinting (IOB) of different CMF tissues, including bone, skin, and composite (hard/soft) tissues, is demonstrated directly on rats in a surgical setting. A novel extrudable osteogenic hard tissue ink is introduced, which induced substantial bone regeneration, with ≈80% bone coverage area of calvarial defects in 6 weeks. Using droplet-based bioprinting, the soft tissue ink accelerated the reconstruction of full-thickness skin defects and facilitated up to 60% wound closure in 6 days. Most importantly, the use of a hybrid IOB approach is unveiled to reconstitute hard/soft composite tissues in a stratified arrangement with controlled spatial bioink deposition conforming the shape of a new composite defect model, which resulted in ≈80% skin wound closure in 10 days and 50% bone coverage area at Week 6. The presented approach will be absolutely unique in the clinical realm of CMF defects and will have a significant impact on translating bioprinting technologies into the clinic in the future.     

Impact of relative speed on node vicinity dynamics in VANETs

Communication protocols generally rely on the existence of very long multihop paths to reach distant nodes. They disregard, however, how often such paths indeed occur, and how long they persist, especially in highly dynamic mobile networks. In this direction, this paper evaluates quantitatively the influence of node relative speed on path establishment and maintenance, using real and synthetic vehicular network traces. We propose a methodology for vehicular network analysis where both relative speeds and hop distances are used as parameters to characterize node vicinity. Results show that contact opportunities highly depend on the relative speed and the hop distance between nodes. In sparser scenarios, the number of contacts between nodes separated by more than 3 hops or even between neighbors with relative speed above 40 km/h is negligible. This confirms the intuition that contacts at lower relative speeds and at few hop distances happen more often. In addition, contacts last longer as the number of hops between nodes decreases. Nevertheless, we can still find multihop paths able to transmit messages at high relative speeds, even though less often. We also demonstrate that relative speeds reduce the number of useful contacts more severely when compared to the hop distance. For last, we show that it is possible to increase the number of successful packet transmissions by simply applying the outcomes of this work, without any sophisticated model, avoiding the waste of resources, such as energy and bandwidth.

     

About the geometry of asymmetric fiber orientation distributions

Fiber orientation distributions (FODs) based on diffusion-sensitized magnetic resonance imaging are usually symmetric, primarily due to the nature of the diffusion. In contrast, the underlying fiber configurations are not, as bending or fanning configurations are inherently asymmetric. We propose to dismiss the symmetry of the FOD to additionally encode the asymmetry of the underlying fiber configuration. This is of particular importance for low resolution images that are common in diffusion weighted imaging. We set up the mathematical foundations and geometric interpretations of asymmetric FODs and show how one can benefit from these considerations. We infer a continuity condition that is used as a prior during FOD estimation by constrained spherical deconvolution. This new prior shows superior performance in comparison to other spatial regularization strategies in reliability and accuracy.     

Perfluorooctyl Bromide Polymeric Capsules as Dual Contrast Agents for Ultrasonography and Magnetic Resonance Imaging

Polymeric capsules with a thick shell made of biodegradable and biocompatible polymer and a liquid core of perfluorooctyl bromide (PFOB) were evaluated for stability as well as for ultrasound and magnetic resonance imaging (MRI) contrast enhancement. The method of preparation allows the mean capsule diameter to be regulated between 70 nm and 25 µm and the capsule thickness‐to‐radius ratio from 0.25 to 0.54. Capsule diameter remains stable at 37 °C in phosphate buffer for at least 4 and 6 h for nanocapsules and microcapsules, respectively. The in vitro ultrasound signal‐to‐noise ratio (SNR) was measured from 40 to 60 MHz for 6 µm and 150 nm capsules: the SNR increases with capsule concentration up to 20–25 mg mL⁻¹, and then reaches a plateau that depends on capsule diameter (13.5 ± 1.5 dB for 6 µm and 6 ± 2 dB for the 150 nm capsules). The ultrasound SNR is stable for up to 20 min for microcapsules and for several hours for nanocapsules. For nanocapsules, the thinner the shell, the larger the SNR and the more compressible the capsules. Nanocapsule suspensions imaged in vitro with a commercial ultrasound imaging system (normal and tissue harmonic imaging modes, 7–14 MHz probe) were detected down to concentrations of 12.5 mg mL⁻¹. Injections of nanocapsules (200 µg ml⁻¹) in mice in vivo reveal that the initial bolus passage presents significant ultrasound enhancement of the blood pool during hepatic imaging (7–14 MHz probe, tissue harmonic imaging mode). ¹⁹F‐MRI images were obtained in vitro at 9.4T using spin‐echo and gradient echo sequences and allow detecting nanocapsules in suspension (50 mg mL⁻¹). In conclusion, these results show initial feasibility for development of these capsules toward a dual‐modality contrast agent.     

Early voltage in heterojunction bipolar transistors: Quantum tunneling and base recombination effects

An extension of the thermionic emission expression for Early voltage V_A for heterojunction bipolar transistors including quantum mechanical tunneling and base recombination effects is provided. The theoretical model is based on a single flux treatment of the carrier transport invoking the concise notation of scattering matrices. V_A is numerically evaluated under the WKB quantum mechanical approximation for triangular and parabolic barriers. The temperature dependence of the Early voltage is simulated numerically and compared to earlier theoretical V_A predictions and actual experimental results of V_A in heterojunction bipolar transistors.     

Nanostructure optical emitters based on quasibound electron energy levels

Given two energy states (levels) in a quantum well formed by two potential barriers of finite thickness, elementary quantum mechanics tells us that the lower energy state is more tightly bound than the upper state. This produces a longer spatial confinement lifetime in the lower state than in the upper state. This ratio of lifetimes is opposite to that needed for laser action between these states. Furthermore, the lifetime of the lower energy state must be significantly shorter than the electron scattering time for the upper state. These facts have blocked the development of lasers based on these transitions. However, in this paper we report experimental and analytical results on a versatile type of semiconductor heterostructure that overcomes these difficulties. Unlike previous devices, this structure relies on an optical transition between two states which are both above-barrier quasibound states in the ‘classical’ continuum. The oscillator strength is large and the operation of the device clearly demonstrates coherent electron wave behavior. Such structures could represent the basis for a new room-temperature infrared semiconductor laser.     

A renewable single-server queueing system with priorities

A single-server queue with a triple priority system is considered in this paper. The server can fail during its occupation time and is sent for repair immediately.The stationary probabilities of the different states of the system are studied, under the assumption that the arrival time and the service time for the three kinds of customers, and the repair time, all have Poisson distributions with different parameters. The results obtained before, in [Mokaddis et al., Eighth International Congress for Statistics, Computer Science, Social and Demographic Research, Vol. 4, pp. 31–58 (1983)] in the case of a double priority, are derived from the present results as special cases. Moreover the mathematical expectation of the number of customers and the average waiting time of both kinds of customers and more characteristics of the system, in the case of double priority, are obtained. Also, in this paper, we study the system without priority, in the cases of both a triple priority system and a double priority system.     

A new technique in a cutset evaluation

This paper presents a new technique (algorithm) for deducing minimal cutsets of 2-state systems by using minimal pathsets and vice-versa. An example is introduced to demonstrate the new technique.     

Large wavelength shifts in UV-exposed 3 dB and WDM fused taperfibre couplers

The spectral response of 3 dB and 1300/1550 nm wavelength division multiplexing fused taper fibre couplers can be shifted by over 100 nm by exposing the entire coupler with intense UV light at a wavelength of 193 nm and without prior hydrogenation. There is no discernable increase in excess loss. The major contribution to these shifts for these couplers originates in the down- and up-taper regions