Needle-free injection into skin and soft matter with highly focused microjets

The development of needle-free drug injection systems is of great importance to global healthcare. However, in spite of its great potential and research history over many decades, these systems are not commonly used. One of the main problems is that existing methods use diffusive jets, which result in scattered penetration and severe deceleration of the jets, causing frequent pain and insufficient penetration. Another longstanding challenge is the development of accurate small volume injections. In this paper we employ a novel method of needle-free drug injection, using highly-focused high speed microjets, which aims to solve these challenges. We experimentally demonstrate that these unique jets are able to penetrate human skin: the focused nature of these microjets creates an injection spot smaller than a mosquito's proboscis and guarantees a high percentage of the liquid being injected. The liquid substances can be delivered to a much larger depth than conventional methods, and create a well-controlled dispersion pattern. Thanks to the excellent controllability of the microjet, small volume injections become feasible. Furthermore, the penetration dynamics is studied through experiments performed on gelatin mixtures (human soft tissue equivalent) and human skin, agreeing well with a viscous stress model which we develop. This model predicts the depth of the penetration into both human skin and soft tissue. The results presented here take needle-free injections a step closer to widespread use

Lighting the World: the first application of an open source, spatial electrification tool (OnSSET) on Sub-Saharan Africa

In September 2015, the United Nations General Assembly adopted Agenda 2030, which comprises a set of 17 Sustainable Development Goals (SDGs) defined by 169 targets. 'Ensuring access to affordable, reliable, sustainable and modern energy for all by 2030' is the seventh goal (SDG7). While access to energy refers to more than electricity, the latter is the central focus of this work. According to the World Bank's 2015 Global Tracking Framework, roughly 15% of the world's population (or 1.1 billion people) lack access to electricity, and many more rely on poor quality electricity services. The majority of those without access (87%) reside in rural areas. This paper presents results of a geographic information systems approach coupled with open access data. We present least-cost electrification strategies on a country-by-country basis for Sub-Saharan Africa. The electrification options include grid extension, mini-grid and stand-alone systems for rural, peri-urban, and urban contexts across the economy. At low levels of electricity demand there is a strong penetration of standalone technologies. However, higher electricity demand levels move the favourable electrification option from stand-alone systems to mini grid and to grid extensions

Coordinated control of multiple series FACTS devices

This paper examines the use of thyristor controlled series capacitors (TCSCs) for the redistribution of active power flows (PFs) in a transmission network and presents a simple model of a hierarchical coordinated control system for multiple devices. The TCSC is one of the representatives of the flexible AC transmission system (FACTS) devices family and is a solid-state converter that has the capability of controlling PFs in transmission lines by changing its reactance. The model is based on a sensitivity analysis of the system plus knowledge of TCSC behavior and is verified by steady state simulation. A 12 bus, 19 line, 5 TCSC system is presented as an example. It is shown that TCSCs can be very effective for controlling PFs in lines and unload overloaded lines by the coordinated actions of multiple TCSC devices, without their mutual negative influence, using locally measurable input signal

Flexible Power Control in Electric Grids

Advanced power flow control for multiple Flexible Alternative Current Transmission System (FACTS) devices is described here. An installation of multiple FACTS devices offers a great advantage concerning the flexibility of a system-wide power flow control. However, their individual unco-ordinated control actions may cause mutual negative effects. Therefore, a control tool for multiple FACTS devices capable of managing system congestions in a continuously changing deregulated environment has been developed. The controller prototype has been tested using simulation software for power systems in order to assess its performance considering different scenarios. As an example, the Swiss power system has been used in this paper

Application of fuzzy logic techniques for the coordinated power flow control by multiple series FACTS devices

This work describes the development of a fuzzy logic based control system capable of governing multiple thyristor-controlled series capacitors (TCSCs). The main purpose of the presented coordinated control system is the improvement of active power flow control in a power system. The proposed control strategy is quite simple; therefore it does not require intensive computations on on-line computers. The control system has been designed as a real time tool constantly monitoring power flows and generating appropriate control signals to each TCSC to maintain acceptable power flow levels in the normal and N-1 steady-state modes. The prototype control system has been interfaced with power system simulation software to test its effectiveness through nonlinear simulations using the Central European-CIS interconnected power system as the study case. The results obtained are presente

Optimizing a Battery Energy Storage System for Frequency Control Application in an Isolated Power System

This paper presents a method for optimal sizing and operation of a battery energy storage system (BESS) used for spinning reserve in a small isolated power system. Numerical simulations are performed on a load-frequency control (LFC) dynamic simulator of the isolated network. A novel control algorithm using adjustable state of charge limits is implemented and tested on a BESS dynamic model. An optimal sizing procedure of the BESS is developed for an isolated power system in order to achieve highest expected profitability of the device. The BESS can increase significantly the power system stability, the grid security, and the planning flexibility for a small isolated power system with low grid inertia. Meanwhile, it fulfills the frequency control requirements with a high expected economic profitability