397 research outputs found
Laboratory and theoretical investigation of the near critical phase behaviour of hydrocarbon-injection gas systems
Abstract unavailable please refer to PD
The origin of the FeIV=O intermediates in cytochrome aa3 oxidase
AbstractThe dioxygen reduction mechanism in cytochrome oxidases relies on proton control of the electron transfer events that drive the process. Proton delivery and proton channels in the protein that are relevant to substrate reduction and proton pumping are considered, and the current status of this area is summarized. We propose a mechanism in which the coupling of the oxygen reduction chemistry to proton translocation (P→F transition) is related to the properties of two groups of highly conserved residues, namely, His411/G386-T389 and the heme a3–propionateA–D399–H403 chain. This article is part of a Special Issue entitled: Respiratory Oxidases
Leading by example: Exploring the influence of design examples on children’s creative ideation
Creative ideation is integral to the design process; to be considered creative an idea must be
deemed both novel and appropriate. Design examples are often provided to inspire creativity
but may also constrain designers’ imaginations (design fixation), a phenomenon observed
during children’s ideation in participatory design (PD). This paper addresses a gap in the
literature by empirically investigating this phenomenon through an exploratory case study of
two game narrative design workshops involving 37 children. Children’s design ideas from
these workshops were systematically coded by two researchers following a deductive content
analysis approach and inter-rater reliability was established. Our findings show that utilising
design examples can ensure appropriateness (i.e. narrative relevance and coherence), and
albeit some design fixation more often facilitates the creative process by enabling existing
ideas to be recycled and combined with novel ideas. This research contributes potential
methodological adaptations to better foster children’s creativity during PD
Improving Midstream Urine Collection for Urine Culture through the Use of a Novel Device, FlipCatch
Background : A midstream, clean-catch urine sample is the gold standard for diagnosing urinary tract infections and determining treatment. The current method of collection is not standardized, frustrating both patients and providers. The current method results in a high rate of contaminated samples (30-40%), which often need to be repeated in order to obtain a diagnosis and antibiotic susceptibility data. A design project was conducted in order to create a more effective urine collection device with the goals of decreasing contamination and improving patient and provider experience.
Methods : We conducted interviews of patients, allied health professionals, physicians, and clinical microbiologists involved in the urine collection process in order to gain insight into current systemic flaws in urine collection (n=18). A set of design criteria were established based on interview feedback. Following conceptualization and rough prototyping, feasible designs were 3D printed in PLA (polylactic acid) filament and tested for functionality using water. Users were asked to urinate in the final design and rate its comfort and ease of use.
Results : FlipCatch is a gravity-fed urine collection device featuring an ergonomic funnel, which helps guide the stream onto a cellulose sponge mounted to a rotating arm. Once the sample is collected, staff can utilize the Vacutainer® receptacle for sample processing. User testing of the device was limited due to the small number of prototypes able to be 3D printed, but the feedback was positive.
Conclusions : FlipCatch could solve many of the current problems with urine collection, yet significant improvements still need be implemented in order for the device to be feasible. Mechanical optimization and more detailed financial analyses with updated manufacturing costs will be needed. In the future, a pilot study at Jefferson could be used to measure contamination rate and user satisfaction in FlipCatch compared to current practice
The Effect of Ultrasonic Excitation on the Electrical Properties and Microstructure of Printed Electronic Conductive Inks
Abstract: Ultrasonic Additive Manufacturing (UAM) is an advanced manufacturing technique, which enables the embedding of electronic components and interconnections within solid aluminium structures, due to the low temperature encountered during material bonding. In this study, the effects of ultrasonic excitation, caused by the UAM process, on the electrical properties and the microstructure of thermally cured screen printed silver conductive inks were investigated. The electrical resistance and the dimensions of the samples were measured and compared before and after the ultrasonic excitation. The microstructure of excited and unexcited samples was examined using combined Focused Ion Beam and Scanning Electron Microscopy (FIB/SEM) and optical microscopy. The results showed an increase in the resistivity of the silver tracks after the ultrasonic excitation, which was correlated with a change in the microstructure: the size of the silver particles increased after the excitation, suggesting that inter-particle bonding has occurred. The study also highlighted issues with short circuiting between the conductive tracks and the aluminium substrate, which were attributed to the properties of the insulating layer and the inherent roughness of the UAM substrate. However, the reduction in conductivity and observed short circuiting were sufficiently small and rare, which leads to the conclusion that printed conductive tracks can function as interconnects in conjunction with UAM, for the fabrication of novel smart metal components
Approaching the screenplay as a complex system: underlying mechanics, interrelating dynamics and the plot-algorithmic process
The advancement of theoretical screenwriting has been limited to popularized “how-to” techniques to further investigate the field. These techniques were based on internalised rules-of-thumb drawn from inductive observations of existing screenplays. Such analyses failed to provide answers to two troubling fundamental questions: first, what makes stories emerge in the context of narrative, and second, what are the underlying dynamics that allow a screenplay to function as a unified whole? The contribution of Screenplectics lies in first, by explaining how a screenplay functions synergistically, and appropriating the necessary metaphors, systemically. And second, by explaining the mechanism that is employed between compositional interactions in various structural levels that allows the coherent accumulative derivative we call story to emerge. The transition from an empirical to a theoretical perspective is achieved by examining such dynamics under the prism of holism and through the introduction of characteristics of complex systems: a network of components arranged hierarchically that interact parallel to one another in non-linear ways. This hierarchy shapes the foundation of the different layers of structure in a screenplay: deep, intermediate and surface structure. This research consolidates the notion that for the comprehension of such complex dynamics a more comprehensive theory of narrative is required
Ultrasonic Additive Manufacturing as a form-then-bond process for embedding electronic circuitry into a metal matrix
Ultrasonic Additive Manufacturing (UAM) is a hybrid manufacturing process that involves the layer-by-layer ultrasonic welding of metal foils in the solid state with periodic CNC machining to achieve the desired 3D shape. UAM enables the fabrication of metal smart structures, because it allows the embedding of various components into the metal matrix, due to the high degree of plastic metal flow and the relatively low temperatures encountered during the layer bonding process. To further the embedding capabilities of UAM, in this paper we examine the ultrasonic welding of aluminium foils with features machined prior to bonding. These pre-machined features can be stacked layer-by-layer to create pockets for the accommodation of fragile components, such as electronic circuitry, prior to encapsulation. This manufacturing approach transforms UAM into a “form-then-bond” process. By studying the deformation of aluminium foils during UAM, a statistical model was developed that allowed the prediction of the final location, dimensions and tolerances of pre-machined features for a set of UAM process parameters. The predictive power of the model was demonstrated by designing a cavity to accommodate an electronic component (i.e. a surface mount resistor) prior to its encapsulation within the metal matrix. We also further emphasised the importance of the tensioning force in the UAM process. The current work paves the way for the creation of a novel system for the fabrication of three-dimensional electronic circuits embedded into an additively manufactured complex metal composite
The effect of ultrasonic excitation on the electrical properties and microstructure of printed electronic conductive inks
Ultrasonic Additive Manufacturing (UAM) is an advanced manufacturing technique, which enables the embedding of electronic components and interconnections within solid aluminium structures, due to the low temperature encountered during material bonding. In this study, the effects of ultrasonic excitation, caused by the UAM process, on the electrical properties and the microstructure of thermally cured screen printed silver conductive inks were investigated. The electrical resistance and the dimensions of the samples were measured and compared before and after the ultrasonic excitation. The microstructure of excited and unexcited samples was examined using combined Focused Ion Beam and Scanning Electron Microscopy (FIB/SEM) and optical microscopy. The results showed an increase in the resistivity of the silver tracks after the ultrasonic excitation, which was correlated with a change in the microstructure: the size of the silver particles increased after the excitation, suggesting that inter-particle bonding has occurred. The study also highlighted issues with short circuiting between the conductive tracks and the aluminium substrate, which were attributed to the properties of the insulating layer and the inherent roughness of the UAM substrate. However, the reduction in conductivity and observed short circuiting were sufficiently small and rare, which leads to the conclusion that printed conductive tracks can function as interconnects in conjunction with UAM, for the fabrication of novel smart metal components
The effect of ultrasonic excitation on the electrical properties and microstructure of printed electronic conductive inks
Ultrasonic Additive Manufacturing (UAM) is an advanced manufacturing technique, which enables the embedding of electronic components and interconnections within solid aluminium structures, due to the low temperature encountered during material bonding. In this study, the effects of ultrasonic excitation, caused by the UAM process, on the electrical properties and the microstructure of thermally cured screen printed silver conductive inks were investigated. The electrical resistance and the dimensions of the samples were measured and compared before and after the ultrasonic excitation. The microstructure of excited and unexcited samples was examined using combined Focused Ion Beam and Scanning Electron Microscopy (FIB/SEM) and optical microscopy. The results showed an increase in the resistivity of the silver tracks after the ultrasonic excitation, which was correlated with a change in the microstructure: the size of the silver particles increased after the excitation, suggesting that inter-particle bonding has occurred. The study also highlighted issues with short circuiting between the conductive tracks and the aluminium substrate, which were attributed to the properties of the insulating layer and the inherent roughness of the UAM substrate. However, the reduction in conductivity and observed short circuiting were sufficiently small and rare, which leads to the conclusion that printed conductive tracks can function as interconnects in conjunction with UAM, for the fabrication of novel smart metal components
Predicting COVID-19 hospitalizations:The importance of healthcare hotlines, test positivity rates and vaccination coverage
In this study, we developed a negative binomial regression model for one-week ahead spatio-temporal predictions of the number of COVID-19 hospitalizations in Uppsala County, Sweden. Our model utilized weekly aggregated data on testing, vaccination, and calls to the national healthcare hotline. Variable importance analysis revealed that calls to the national healthcare hotline were the most important contributor to prediction performance when predicting COVID-19 hospitalizations. Our results support the importance of early testing, systematic registration of test results, and the value of healthcare hotline data in predicting hospitalizations. The proposed models may be applied to studies modeling hospitalizations of other viral respiratory infections in space and time assuming count data are overdispersed. Our suggested variable importance analysis enables the calculation of the effects on the predictive performance of each covariate. This can inform decisions about which types of data should be prioritized, thereby facilitating the allocation of healthcare resources.</p
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