Experimental Study of Two-phase Seperators for Vapor Compression Systems in Household Appliances

Two-phase separation offers an increase in refrigeration system efficiency with the added benefit of using a passive component. Although, a large amount research has been established in the refrigeration field for high mass flux systems, there is still ample opportunity to expand this application and knowledge in the refrigeration home appliances sector which require lower mass flux. The objective of this study was to evaluate the design of liquid-vapor gravity separators for low mass flux systems (1.5 – 3.5 lbm/ft^2hr). In the experimental method, the independent parameters varied were: Inlet Quality, Inlet Pressure, Inlet Mass Flow, Top Branch Flow Ratio and Separator Geometry. The dependent parameter was determined as, x_2, the Outlet Vapor Branch Quality. The two separator geometries which were designed, fabricated, and tested varied in aspect ratio, which is defined as the ratio of the height to the body diameter of the separator. The aspect ratio of the first geometry was 10, and it consisted of a tall separator height (4.125 in) with a narrow separator body diameter (0.423 in). The second geometry had an aspect ratio of 2, and it consisted of a short separator height (1.75 in) with a wide separator body diameter (0.742 in). The separator body was made of clear PVC tubing material in order visualize the flow conditions at different operating points. The results of the study showed that both geometries perform similarly. At low and high liquid Reynolds number, the flows characteristically show no significant vapor shearing and no vapor exiting through the liquid branch, as long as a liquid build-up was visually present in the separator; this indicates that vapor phase momentum is not high enough to penetrate through the high bulk viscosity of the liquid phase. Therefore, evaluating the vapor quality through the vapor branch was explicitly carried out by assuming the vapor quality through the liquid branch as 0. Thus, the results indicate that the primary factor to influence separation in this study was the balance maintained between the inlet quality and top branch flow ratio. Overall, separation was not highly sensitive to the rest of the factors in the tested ranges applicable to small scale refrigeration appliances. When inlet quality was greater than top branch flow ratio, no clear liquid-vapor interface was present and the mixture entering the separator was characteristic of misty flow, thus no liquid buildup was found within the separator.  However when the inlet quality was less than the top branch flow ratio, the liquid-vapor interface was visible and a liquid build-up was observed within the separator vessel

Control and Morphology Optimization of Passive Asymmetric Structures for Robotic Swimming

Aquatic creatures exhibit remarkable adaptations of their body to efficiently interact with the surrounding fluid. The tight coupling between their morphology, motion, and the environment are highly complex but serves as a valuable example when creating biomimetic structures in soft robotic swimmers. We focus on the use of asymmetry in structures to aid thrust generation and maneuverability. Designs of structures with asymmetric profiles are explored so that we can use morphology to `shape' the thrust generation. We propose combining simple simulation with automatic data-driven methods to explore their interactions with the fluid. The asymmetric structure with its co-optimized morphology and controller is able to produce 2.5 times the useful thrust compared to a baseline symmetric structure. Furthermore these asymmetric feather-like arms are validated on a robotic system capable of forward swimming motion while the same robot fitted with a plain feather is not able to move forward

Anterior nasal versus nasal mid-turbinate sampling for a SARS-CoV-2 antigen-detecting rapid test: does localisation or professional collection matter?

INTRODUCTION: Most SARS-CoV-2 antigen-detecting rapid diagnostic tests require nasopharyngeal sampling, which is frequently perceived as uncomfortable and requires healthcare professionals, thus limiting scale-up. Nasal sampling could enable self-sampling and increase acceptability. The term nasal sampling is often not used uniformly and sampling protocols differ. METHODS: This manufacturer-independent, prospective diagnostic accuracy study, compared professional anterior nasal and nasal mid-turbinate sampling for a WHO-listed SARS-CoV-2 antigen-detecting rapid diagnostic test. The second group of participants collected a nasal mid-turbinate sample themselves and underwent a professional nasopharyngeal swab for comparison. The reference standard was real-time polymerase chain reaction (RT-PCR) using combined oro-/nasopharyngeal sampling. Individuals with high suspicion of SARS-CoV-2 infection were tested. Sensitivity, specificity, and percent agreement were calculated. Self-sampling was observed without intervention. Feasibility was evaluated by observer and participant questionnaires. RESULTS: Among 132 symptomatic adults, both professional anterior nasal and nasal mid-turbinate sampling yielded a sensitivity of 86.1% (31/36 RT-PCR positives detected; 95%CI: 71.3-93.9) and a specificity of 100.0% (95%CI: 95.7-100). The positive percent agreement was 100% (95%CI: 89.0-100). Among 96 additional adults, self nasal mid-turbinate and professional nasopharyngeal sampling yielded an identical sensitivity of 91.2% (31/34; 95%CI 77.0-97.0). Specificity was 98.4% (95%CI: 91.4-99.9) with nasal mid-turbinate and 100.0% (95%CI: 94.2-100) with nasopharyngeal sampling. The positive percent agreement was 96.8% (95%CI: 83.8-99.8). Most participants (85.3%) considered self-sampling as easy to perform. CONCLUSION: Professional anterior nasal and nasal mid-turbinate sampling are of equivalent accuracy for an antigen-detecting rapid diagnostic test in ambulatory symptomatic adults. Participants were able to reliably perform nasal mid-turbinate sampling themselves, following written and illustrated instructions. Nasal self-sampling will facilitate scaling of SARS-CoV-2 antigen testing

Local Water Loop : Vorstudie für einen energie- und wasserautarken Waschmaschinenbetrieb

Während der Bedarf an Süsswasser weltweit stetig steigt, wird dessen Verfügbarkeit immer knapper. Um dem entgegenzuwirken, ist die lokale Behandlung und Wiederverwendung von Grauwasser ein vielversprechender Ansatz. Von besonderem Interesse sind der Einsatz von grünen Wänden, als platzsparende Alternative zu Pflanzenkläranlagen, und Filtersäulen zur biologischen Reinigung des Abwassers. Im vorliegenden Projekt wurden die Grundlagen für einen energie- und wasserautarken Waschmaschinenbetrieb, basierend auf der biologischen Reinigungstechnologie, erarbeitet. Es wurde eine Reihe von Experimenten durchgeführt, um Waschmaschinenabwasser zu charakterisieren, eine geeignete Vorreinigung auszuwählen, ein geeignetes Filtersubstrat für die grüne Wand zu identifizieren, die Keimbelastung zu analysieren und den Energieautarkiegrad zu bestimmen und zu optimieren. Die Analyse des Waschmaschinenabwassers zeigte, dass ein Grossteil der Verschmutzung im Abwasser vom Waschmittel selbst stammt. Daher ist die Verwendung eines ökologischen Waschmittels und dessen korrekte Dosierung essenziell für einen ressourceneffizienten Betrieb. Für die physikalisch-mechanische Vorreinigung wurden ein Sandfilter und ein Feinfilter getestet. Aufgrund der hohen Faserbelastung im Waschmaschinenabwasser zeigte sich der Sandfilter als ungeeignet, da er schnell verstopfte. Stattdessen konnte mit dem Feinfilter eine gute Vorreinigung erzielt werden. Die Faserbelastung im Waschmaschinenabwasser betrug durchschnittlich 25 mg/L vor der Vorreinigung und konnte durch den Feinfilter auf 2 mg/L reduziert werden. Die Analyse der Reinigungsleistung verschiedener Substrate für die grüne Wand, darunter Vulkaponic, Vulkaponic/Pflanzenkohle-Mischung und Perlit, zeigte, dass mit reinem Vulkaponic die besten Ergebnisse erzielt wurden. Die Reinigungseffizienz von Vulkaponic betrug im Durchschnitt 85%, während die Mischung aus Vulkaponic und Pflanzenkohle eine Reinigungsleistung von 78% aufwies. Perlit erreichte eine Reinigungsleistung von 62%. Die Keimbelastung im Kreislaufsystem der Waschmaschine nimmt nach der Reinigung und UV-Behandlung stetig ab, sodass die Wasserqualität den Anforderungen an Badegewässer entspricht. Die Konzentration der aeroben mesophilen Keime sank von 130’000 KBE/mL auf 1’400 KBE/mL nach der UV-Behandlung. Dies bestätigt die Effektivität der angewandten Reinigungs- und Desinfektionsverfahren. Um den Energieautarkiegrad über ein Jahr zu bestimmen, wurden die gemessenen Werte auf ein Jahr extrapoliert. In der jetzigen Ausführung kann somit ein Autarkiegrad von 30% erzielt werden. Durch den Einsatz zusätzlicher Optimierungsmassnahmen wie die Nutzung von zusätzlichen Solarpanels und einer optimierten Steuerung kann dieser Wert auf 66% erhöht werden. Am Zielstandort in Kapstadt, Südafrika könnte damit ein Autarkiegrad von 86% erreicht werden. Die gewonnenen Erkenntnisse aus den Experimenten dienen dazu, den energie- und wasserautarken Waschmaschinenbetrieb in Folgeprojekten weiterzuentwickeln und zu optimieren

Quantifying sources of variability in infancy research using the infant-directed-speech preference

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure. (This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 798658.

Stratospheric aerosol - Observations, processes, and impact on climate

Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes

Proton diffusion along the membrane surface of thylakoids is not enhanced over that in bulk water

In photosynthesis and respiration ATP synthesis is powered by a transmembrane protonmotive force. Membrane bound proton pumps and proton translocating ATPsynthases are coupled by lateral proton flow. Whether it leads through the aqueous bulk phases (chemiosmotic theory) or whether it is confined to the membrane or the membrane water interface, is still controversial. Another related controversy is whether or not proton diffusion along the interface between a phospholipid membrane and water is enhanced over the one in bulk water. Thylakoid membranes of plant chloroplasts are intrinsically closely apposed (≈5 nm). To study lateral proton diffusion along the narrow interfacial domain between adjacent thylakoid membranes, we stimulated the proton pumps by a flash of light. This generates an alkalinization jump. In the absence of ADP the membrane is relatively proton tight. Therefore, the alkalinization jump relaxes into the medium. The relaxation kinetics as function of pH and added buffers were studied by flash spectrophotometry. The results were compared with a theory dealing with the diffusion of protons, hydroxyl ions, and mobile buffers plus the action of fixed buffers. We came to the conclusion that the lateral diffusion coefficient both, for H(+) and for OH(-) was less or of same magnitude as in bulk water

{Bis[2-(diisopropylphosphanyl)ethyl]amine}carbonyl(tetrahydroborato)cobalt(I)

In the structure of title borohydride pincer complex, [Co(BH4)(C16H37NP2)(CO)], the cobalt(I) metal exhibits a distorted square-pyramidal coordination geometry with the basal positions occupied by the P and N atoms of the tridentate ligand and by the C atom of the carbon monoxide ligand. In the crystal, molecules interact only by van der Waals forces