A process chain for integrating microfluidic interconnection elements by micro- overmoulding of thermoplastic elastomers

This paper presents a process chain for in-line integration of microfluidic interconnection elements by a variant of micro-injection moulding (mu IM). A SEBS-based thermoplastic elastomer (TPE) was moulded over polymethylmethacrylate (PMMA) to produce a hybrid microfluidic structure with an aspect ratio of 2. The process chain implemented micro-milling for fabricating micro-structured tool inserts, and mu IM and micro-overmoulding was used for replication. A two-plate mould was used for moulding the substrate, whilst a three-plate mould with a replaceable insert was used for TPE overmoulding. The presented application was an interconnect system for a microfluidic device, which enabled direct fitting of standard tubes into microfluidic substrates. A leakage test showed that the interconnection was leak-proof within a range of flow rates between 0.32 and 0.62 ml min(-1)

Automated analysis of radar imagery of Venus: handling lack of ground truth

Lack of verifiable ground truth is a common problem in remote sensing image analysis. For example, consider the synthetic aperture radar (SAR) image data of Venus obtained by the Magellan spacecraft. Planetary scientists are interested in automatically cataloging the locations of all the small volcanoes in this data set; however, the problem is very difficult and cannot be performed with perfect reliability even by human experts. Thus, training and evaluating the performance of an automatic algorithm on this data set must be handled carefully. We discuss the use of weighted free-response receiver-operating characteristics (wFROCs) for evaluating detection performance when the “ground truth” is subjective. In particular, we evaluate the relative detection performance of humans and automatic algorithms. Our experimental results indicate that proper assessment of the uncertainty in “ground truth” is essential in applications of this nature

Creating movable interfaces by micro-powder injection moulding

This paper presents a novel in situ technique to produce articulated components with high-precision, micro-scale movable interfaces by micro-powder injection moulding (μPIM). The presented process route is based on the use of micro-scale sacrificial layer between the movable subcomponents which is eliminated during the debinding step, creating a dimensionally-controlled, micro-scale mobile interface. The fabrication technique combines the advantages of micro-powder overmoulding, catalytic debinding and sintering. The demonstrated example was a finger bone prosthesis joint consisting of two sub-components with an interface between components of 200 μm in size. The geometries of the sub-components were designed such that they are inseparable throughout the process whilst allowing them to move relative to each other after the debinding stage. The components produced showed the feasibility of the process route to produce readily-assembled meso-, and potentially micro-, scale articulated system

The influence of hydrodynamics and particle size on the rejection properties of ultrafiltration membranes

A mathematical model based on the flow hydrodynamics is developed to calculate the treatment efficiency of ultrafiltration process. This model relates the treatment efficiency with the consideration of both fixed parameters and variable parameters. The fixed parameters are function of the intrinsic rejection coefficient, diffusion coefficient, and viscosity whereas the variable parameters can be related to the fluid velocity, volume flux, and cartridge dimensions. The model has been examined by solutions with solutes that have different molecular weights. The experimental data fits the proposed mathematical model very closely suggesting its suitability to evaluate the rejection efficiency in ultrafiltration. As such the mathematical model can be used to evaluate the intrinsic rejection coefficient that can be used to determine the solvent flux in Kedem Katchalisky model. The role of the particle size is investigated by using a log -log plot of the intrinsic rejection coefficient and the solute molecular weight. Results shows that modeling of the intrinsic rejection coefficient as log normal probability distribution function is possible. Fluid velocity on the membrane cartridge as an important parameter in the design of ultrafiltration systems

Fungi - an Amalgam of Toxins and Antibiotics: a Mini- Review

Fungi are eukaryotes with many functions. Earlier, fungi were classified in the plant kingdom but were later classified as a separate kingdom due to their unique cell walls. Fungi are heterotrophs like animals and are more closely related to animals. The perception of fungi is inconspicuous due to their small sizes and their ability to grow symbiotically in plants, animals, other fungi, and parasites. Fungi are used for their nutrition, fermentation potential, and bactericidal potential. However, fungi are also toxic due to certain bioactive compounds known as mycotoxins. Candida and Aspergillus are invasive species that contribute to a high percentage of mycoses in oncological and haematological patients. The mortality rate due to invasive aspergillosis and candidiasis is high, at 4% and 2%, respectively. In the agriculture sector, a significant contributor to damage to crops globally is the invasion of filamentous fungi. Fungi invasion destroys over 125 million tons of wheat, rice, soybeans, potatoes, and maize annually. If prevented, 600 million people may be fed. Therefore, it is vital to consider the dual role of fungi, therapeutic, and pathogenic

African American muslim fathers and the factors that influence their notion of fatherhood

This is a qualitative study that explores African American Muslim father notion of fatherhood. Sixteen African American Sunni Muslims participated in the study. Over 90 percent of the research respondents are converts to Islam. These men perceive their conversion as a reclaiming of their heritage stripped from them when their African ancestors were forcibly taken from Africa and brought to America as slave. While this group of father have been omitted from researchers attention, they are integral members of the African American community. By making Islam the center of their lives these African American Muslim fathers see an active relationship with their children as being essential to their social identities as Muslim men and also as African American men. While sharing similar social challenge as the men in the general African American community these Muslim father have found marriage and commitment to their children not only as a way of fulfilling their religious obligations but also as a way of over coming those difficult challenges that most African American men face living in the United States

Flatness optimization of micro-injection moulded parts: The case of a PMMA microfluidic component

Micro-injection moulding (µ-IM) has attracted a lot of interest because of its potential for the production of low-cost, miniaturized parts in high-volume. Applications of this technology are, amongst others, microfluidic components for lab-on-a-chip devices and micro-optical components. In both cases, the control of the part flatness is a key aspect to maintaining the component's functionality. The objective of this work is to determine the factors affecting the flatness of a polymer part manufactured by µ-IM and to control the manufacturing process with the aim of minimizing the in-process part deformation. As a case study, a PMMA microfluidic substrate with overall dimensions of 10 mm diameter and 1 mm thickness was investigated by designing a µ-IM experiment having flatness as the experimental response. The part flatness was measured using a micro-coordinate measuring machine. Finite elements analysis was also carried out to study the optimal ejection pin configuration. The results of this work show that the control of the µ-IM process conditions can improve the flatness of the polymer part up to about 15 µm. Part flatness as low as 4 µm can be achieved by modifying the design of the ejection system according to suggested guideline

Attention focussing and anomaly detection in real-time systems monitoring

In real-time monitoring situations, more information is not necessarily better. When faced with complex emergency situations, operators can experience information overload and a compromising of their ability to react quickly and correctly. We describe an approach to focusing operator attention in real-time systems monitoring based on a set of empirical and model-based measures for determining the relative importance of sensor data

A Complexity and Quality Evaluation of Block Based Motion Estimation Algorithms

Motion estimation is a method, by which temporal redundancies are reduced, which is an important aspect of video compression algorithms. In this paper we present a comparison among some of the well-known block based motion estimation algorithms. A performance evaluation of these algorithms is proposed to decide the best algorithm from the point of view of complexity and quality for noise-free video sequences and also for noisy video sequences.