Wirelessly Powered Drug-Free and Anti-Infective Smart Bandage for Chronic Wound Care.

We present a wirelessly powered ultraviolet-C (UVC) radiation-based disinfecting bandage for sterilization and treatment in chronic wound care and management. The bandage contains embedded low-power UV light-emitting diodes (LEDs) in the 265 to 285 nm range with the light emission controlled via a microcontroller. An inductive coil is seamlessly concealed in the fabric bandage and coupled with a rectifier circuit to enable 6.78 MHz wireless power transfer (WPT). The maximum WPT efficiency of the coils is 83% in free space and 75% on the body at a coupling distance of 4.5 cm. Measurements show that the UVC LEDs are emitting radiant power of about 0.6 mW and 6.8 mW with and without fabric bandage, respectively, when wirelessly powered. The ability of the bandage to inactivate microorganisms was examined in a laboratory which shows that the system can effectively eradicate Gram-negative bacteria, Pseudoalteromonas sp. D41 strain, on surfaces in six hours. The proposed smart bandage system is low-cost, battery-free, flexible and can be easily mounted on the human body and, therefore, shows great promise for the treatment of persistent infections in chronic wound care.

The Staircase Drive-A Novel Actuator Design Optimised for Daisy-Chaining and Minimum Stress Load Coupling.

This work presents a novel type of actuator that improves over the standard cantilever by permitting daisy-chaining while minimising stress to the joint connecting to the load. A detailed structural and functional comparison of the proposed device against the cantilever actuator as a baseline is given, led by a brief revision of the cantilever actuator as the state-of-the-art that highlights its limitations with respect to daisy-chaining and the stress it inherently creates within the joint connecting to the load when attempting out-of-plane displacement without rotation. Simulations of both devices' performance confirm that the newly proposed device yields the targeted displacement profile that both enables the daisy-chaining of such a device into a higher-order actuator for increased displacement and reduce stress in the joint with the load. This comes at the cost of reduced maximum displacement compared to the cantilever, which can be overcome by daisy-chaining. The proposed device's performance is further evaluated on the basis of manufactured prototypes measured by means of a laser scanning vibrometer. The prototype was manufactured on a 150 µm alumina substrate, and both electrodes and piezoelectric layer were deposited in a thick-film printing process.

An Experimental Comparison of IoT-Based and Traditional Irrigation Scheduling on a Flood-Irrigated Subtropical Lemon Farm.

Over recent years, the demand for supplies of freshwater is escalating with the increasing food demand of a fast-growing population. The agriculture sector of Pakistan contributes to 26% of its GDP and employs 43% of the entire labor force. However, the currently used traditional farming methods such as flood irrigation and rotating water allocation system (Warabandi) results in excess and untimely water usage, as well as low crop yield. Internet of things (IoT) solutions based on real-time farm sensor data and intelligent decision support systems have led to many smart farming solutions, thus improving water utilization. The objective of this study was to compare and optimize water usage in a 2-acre lemon farm test site in Gadap, Karachi, for a 9-month duration, by deploying an indigenously developed IoT device and an agriculture-based decision support system (DSS). The sensor data are wirelessly collected over the cloud and a mobile application, as well as a web-based information visualization, and a DSS system makes irrigation recommendations. The DSS system is based on weather data (temperature and humidity), real time in situ sensor data from the IoT device deployed in the farm, and crop data (Kc and crop type). These data are supplied to the Penman-Monteith and crop coefficient model to make recommendations for irrigation schedules in the test site. The results show impressive water savings (~50%) combined with increased yield (35%) when compared with water usage and crop yields in a neighboring 2-acre lemon farm where traditional irrigation scheduling was employed and where harsh conditions sometimes resulted in temperatures in excess of 50 °C.

A thin-reflector microfluidic resonator for continuous-flow concentration of microorganisms: a new approach to water quality analysis using acoustofluidics.

An acoustofluidic device has been developed for concentrating vegetative bacteria in a continuous-flow format. We show that it is possible to overcome the disruptive effects of acoustic streaming which typically dominate for small target particles, and demonstrate flow rates compatible with the testing of drinking water. The device consists of a thin-reflector multi-layered resonator, in which bacteria in suspension are levitated towards a glass surface under the action of acoustic radiation forces. In order to achieve robust device performance over long-term operation, functional tests have been carried out to (i) maintain device integrity over time and stabilise its resonance frequency, (ii) optimise the operational acoustic parameters, and (iii) minimise bacterial adhesion on the inner surfaces. Using the developed device, a significant increase in bacterial concentration has been achieved, up to a maximum of ~60-fold. The concentration performance of thin-reflector resonators was found to be superior to comparable half-wave resonators.

Characterisation of Crevice and Pit Solution Chemistries Using Capillary Electrophoresis with Contactless Conductivity Detector.

The ability to predict structural degradation in-service is often limited by a lack of understanding of the evolving chemical species occurring within a range of different microenvironments associated with corrosion sites. Capillary electrophoresis (CE) is capable of analysing nanolitre solution volumes with widely disparate concentrations of ionic species, thereby producing accurate and reliable results for the analysis of the chemical compositions found within microenvironment corrosion solutions, such as those found at crevice and pit corrosion sites. In this study, CE with contactless conductivity detection (CCD) has been used to characterize pitting and crevice corrosion solution chemistries for the first time. By using the capillary electrophoresis with contactless conductivity detection (CE-CCD) system, direct and simultaneous detection of seven metal cations (Cu2+, Ni2+, Fe3+, Fe2+, Cr3+, Mn2+, and Al3+) and chloride anions was achieved with a buffer solution of 10 mM 2,6-pyridinedicarboxylic acid and 0.5 mM cetyltrimethylammonium hydroxide at pH 4 using a pre-column complexation method. The detection limits obtained for the metal cations and chloride anions were 100 and 10 ppb, respectively. The CE-CCD methodology has been demonstrated to be a versatile technique capable of speciation and quantifying the ionic species generated within artificial pit (a pencil electrode) and crevice corrosion geometries for carbon steels and nickel-aluminium bronze, thus allowing the evolution of the solution chemistry to be assessed with time and the identification of the key corrosion analyte targets for structural health monitoring.

A new 2-D model of a thin annular disk using a modified assumption.

The work describes an improved 2-D model for a thin annulus by using a modified assumption with regard to coupled vibration. With this approach, the impedance spectrum and displacements due to radial modes, both in radial and thickness direction of a thin ring, are obtained. Bending displacement is investigated by finite element analysis (FEA) and matches our model. The bending in the thickness direction is coupled to radial modes and shows several node circles in the high radial overtone frequency range. The model is validated by FEA with excellent agreement between the new theory and FEA results.