Use of a 3-D Wireless Power Transfer Technique as a Method for Capsule Localization

Capsule endoscopy has been heralded as a technological milestone in the diagnosis and therapeutics of gastrointestinal (GI) pathologies. The location and position of the capsule within the GI tract are important information for subsequent surgical intervention or local drug delivery. Accurate information of capsule location is therefore required during endoscopy. Although radio frequency (RF)-based, magnetic tracking and video localization have been investigated in the past, the complexity of those systems and potential inaccuracy in the localization data necessitate the scope for further research. This article proposes the dual use of a wireless power transfer (WPT) configuration as a method to enable the determination of the location of an endoscopic capsule. Measurements conducted on a homogeneous agar-based liquid phantom predict a maximum error of 12% between the calculated and measured trajectories of the capsule in a working volume of 100 mm $\times 100$ mm $\times 100$ mm

On variable frequency microwave processing of heterogeneous chip-on-board assemblies

Variable Frequency Microwave (VFM) processing of heterogeneous chip-on-board assemblies is assessed using a multiphysics modelling approach. The Frequency Agile Microwave Oven Bonding System (FAMOBS) is capable of rapidly processing individual packages on a Chip-On-Board (COB) assembly. This enables each package to be processed in an optimal manner, with temperature ramp rate, maximum temperature and process duration tailored to the specific package, a significant benefit in assemblies containing disparate package types. Such heterogeneous assemblies may contain components such as large power modules alongside smaller modules containing low thermal budget materials with highly disparate processing requirements. The analysis of two disparate packages has been assessed numerically to determine the applicability of the dual section microwave system to curing heterogeneous devices and to determine the influence of differing processing requirements of optimal process parameters

Effect of fluid dynamics and device mechanism on biofluid behaviour in microchannel systems: modelling biofluids in a microchannel biochip separator

Biofluid behaviour in microchannel systems is investigated in this paper through the modelling of a microfluidic biochip developed for the separation of blood plasma. Based on particular assumptions, the effects of some mechanical features of the microchannels on behaviour of the biofluid are explored. These include microchannel, constriction, bending channel, bifurcation as well as channel length ratio between the main and side channels. The key characteristics and effects of the microfluidic dynamics are discussed in terms of separation efficiency of the red blood cells with respect to the rest of the medium. The effects include the Fahraeus and Fahraeus-Lindqvist effects, the Zweifach-Fung bifurcation law, the cell-free layer phenomenon. The characteristics of the microfluid dynamics include the properties of the laminar flow as well as particle lateral or spinning trajectories. In this paper the fluid is modelled as a single-phase flow assuming either Newtonian or Non-Newtonian behaviours to investigate the effect of the viscosity on flow and separation efficiency. It is found that, for a flow rate controlled Newtonian flow system, viscosity and outlet pressure have little effect on velocity distribution. When the fluid is assumed to be Non-Newtonian more fluid is separated than observed in the Newtonian case, leading to reduction of the flow rate ratio between the main and side channels as well as the system pressure as a whole

The Fabrication and Integration of a 15 MHz Array Within a Biopsy Needle

It is proposed that integrating ultrasound transducer arrays at the tip of tools such as biopsy needles could enable valuable, real-time image feedback during interventional procedures. High-resolution ultrasound imaging has the potential to aid navigation of interventional tools, and to assist diagnosis or treatment via in-vivo tissue characterisation in the breast, amongst many other applications. In order to produce miniature transducer arrays incorporated within biopsy needle-sized packages (2-5 mm diameter), the challenges in micromachining and handling transducer materials at this scale must be overcome. This paper presents fabrication processes used in the micromachining of a 16 element 15 MHz PIN-PMN-PT piezocrystal-polymer composite array and its integration into an 11 G breast biopsy needle. Particular emphasis is given to the manufacturing of the 1-3 dice-and-fill piezocrystal composite, and establishing electrical interconnects. Characterisation measurements have demonstrated operation of each of the 16 elements within the needle case

Megasonic sonication for cost-effective and automatable elution of Cryptosporidium from filters and membranes

Sample processing is a highly challenging stage in the monitoring of waterborne pathogens. This step is time-consuming, requires highly trained technicians and often results in low recovery rates of pathogens. In the UK but also in other parts of the world, Cryptosporidium is the only pathogen directly tested for in routine operational monitoring. The traditional sampling process involves the filtration of 1000 L of water, semi-automated elution of the filters and membranes with recovery rates of about 30–40% typically. This paper explores the use of megasonic sonication in an attempt to increase recovery rates and reduce both the time required for processing and the number of labour-intensive steps. Results demonstrate that megasonic energy assisted elution is equally effective as the traditional manual process in terms of recovery rates. Major advantages are however offered in terms of reduction of the elution volume enabling the current centrifugation stage to be avoided. This saves time, equipment and staff costs and critically removes the step in the process that would be most challenging to automate, paving the way thereby for highly effective automated solutions to pathogens monitoring

Theoretical framework of radiation force in surface acoustic waves for modulated particle sorting

Sorting specific target entities from sample mixtures is commonly used in many macroscale laboratory processing, such as disease diagnosis or treatment. Downscaling of sorting systems enables less laboratory space and fewer quantities of sample and reagent. Such lab-on-a-chip devices can perform separation functions using passive or active sorting methods. Such a method, acoustic sorting, when used in microfluidics, offers contactless, label-free, non-invasive manipulation of target cells or particles and is therefore the topic of active current research. Our phase-modulated sorting technique complements traditional time-of-flight techniques and offers higher sensitivity separation using a periodic signal. By cycling of this periodic signal, the target entities are gradually displaced compared to the background debris, thereby achieving sorting. In this paper, we extend the knowledge on phase-modulated sorting techniques. Firstly, using numerical simulations, we confirm the sorting role of our proposed primary acoustic radiation force within surface wave devices. Secondly, a threefold agreement between analytical, numerical and experimental sorting trajectories is presented

Numerical determination of the secondary acoustic radiation force on a small sphere in a plane standing wave field

Two numerical methods based on the Finite Element Method are presented for calculating the secondary acoustic radiation force between interacting spherical particles. The first model only considers the acoustic waves scattering off a single particle, while the second model includes re-scattering effects between the two interacting spheres. The 2D axisymmetric simplified model combines the Gor’kov potential approach with acoustic simulations to find the interacting forces between two small compressible spheres in an inviscid fluid. The second model is based on 3D simulations of the acoustic field and uses the tensor integral method for direct calculation of the force. The results obtained by both models are compared with analytical equations, showing good agreement between them. The 2D and 3D models take, respectively, seconds and tens of seconds to achieve a convergence error of less than 1%. In comparison with previous models, the numerical methods presented herein can be easily implemented in commercial Finite Element software packages, where surface integrals are available, making it a suitable tool for investigating interparticle forces in acoustic manipulation devices

Electroplating for high aspect ratio vias in PCB manufacturing: enhancement capabilities of acoustic streaming

This paper considers the copper electrodeposition processes in microvias and investigates whether the quality of the electroplating process can be improved by acoustic streaming using megasonic transducers placed into a plating cell. The theoretical results show that acoustic streaming does not take place within the micro-via (either through or blind-via’s), however it does help improve cupric ion transport in the area close to the mouth of a via. This replenishment of cupric ions at the mouth of micro-via leads to better quality filling of the micro-via through diffusion compared to basic conditions. Experiments showing the improved quality of the filling of vias are also presented

Trade-offs in Computer-aided Biomimetics

Biomimetics, the application of mechanisms observed in nature to inform technical solutions, is inherently cross-disciplinary. For the most part, however, practitioners are only expert in one domain, e.g., engineering. Being a layman in the other domain, biology, can make it hard and time-consuming to find and understand relevant information. Computer-Aided Biomimetics (CAB) involves the development of computational tools to overcome this domain-expertise mismatch. Finding a bridge between engineering and biology has been challenging. Although a plethora of methodological approaches have been proposed to bridge the engineering and biology domains, Biomimetics remains adventitious and research intensive. We give an overview of previous research efforts in CAB and motivate our approach that revolves around the resolution of biological trade-offs. This is a unique approach, as previous work has always aimed to extract engineering functions from biological texts. We describe our novel CAB system that extracts trade-offs, a within-domain concept to indicate a dialectical relation between two or more biological traits. We provide a description of our dataset for the extraction of trade-offs from biology research papers, as well as our state-of-the-art Relation Extraction system. The dataset consists of over 1.5k sentences taken from biology research papers, describing a trade-off or similar high-level relation between two or more concepts. Furthermore, we provide an in-depth analysis of the information extracted by our CAB system from a corpus of 10k biology research papers. We show in a qualitative analysis that our system extracts key concepts and relations from biology research papers that are relevant to Biomimetics. Unique to our approach is that our system makes it feasible to collect a comprehensive list of the system parameters and solution principles used in biology. This enables statistical analysis, such as finding the distribution of fundamental principles among the resolution of various trade-offs. Notably, the solutions to trade-offs differ little over various hierarchical levels of biology. This makes our finding relevant to any research that aims to find desired, but underutilized, properties observed in nature

Reliability testing and stress measurement of QFN packages encapsulated by an open-ended microwave curing system

In this paper, the influence of microwave curing on the reliability of a representative electronic package is examined by reliability testing and measurement of residual stresses. A LM358 voltage regulator die was mounted to an open Quad Flat No-leads package (QFN) for reliability testing. For the stress measurement, a specifically designed stress measurement die was mounted to the QFN package. The chips were encapsulated with Hysol EO1080 thermosetting polymer material. Curing was performed using an open-ended microwave oven system equipped with in situ temperature control. Three different temperature profiles for microwave curing were selected according to the requested degree of cure and chemical composition of the cured material. A convection cure profile was selected for the control group samples. Thermal cycling and HAST tests were performed on a total number of 80 chips. 95 QFN packages with stress measurement chips were also manufactured. Increased lifetime expectancy of the microwave cured packaged chips was experimentally demonstrated and measured between 62% to 149% increased lifetime expectancy after Temperature Cycling Test (TCT), and between 63% and 331% after highly Accelerated Ageing Test (HAST) and TCT compared to conventionally cured packages. Analysis of specifically designed stress test chips showed significantly lower residual stresses ranging from 26 MPa to 58.3 MPa within the microwave cured packages compared to conventionally cured packaged chips which displayed residual stresses ranging from 54 MPa to 80.5 MPa. This article therefore provides additional confidence in the industrial relevance of the microwave curing system and its advantages compared to traditional convection oven systems