Atmospheric Aerosol Particle Formation: Aircraft-Based Mass Spectrometric Measurements of Gaseous and Ionic Aerosol Precursors.

The condensational growth of aerosol particles and the formation of fresh, nanometer-sized particles depend primarily upon the presence of H2SO4. Atmospheric ions produced by cosmic rays can initialize the formation of cluster ions, which subsequently may grow by mutual coagulation and condensation of H2SO4 and H2O. In the present work, measurements of the H2SO4 precursor SO2 and atmospheric cluster ions were performed using an ion trap chemical ionisation mass spectrometer(IT-CIMS)and a quadrupole mass spectrometer(QMS). The ion molecule reaction to determine atmospheric SO2 was calibrated isotopically. So problems arising from wall losses and ion hydration are circumvented in an elegant manner. The modifed IT-CIMS was integrated into the German research aircraft Falcon and successfully employed during the international aircraft campaign ITOP(International Transport of Ozone and Precursors). During another aircraft campaign, CONTRACE(Convective Transport of Trace Gases), the QMS aboard the Falcon detected atmospheric cluster ions. Significant correlations between detected small particles and clusterions were found. During ITOP a plume of strongly enhanced SO2 concentrations in the lowermost stratosphere was observed, that originated from North America by overshooting deep convection. Model simulations based on the SO2 data indicate that the measured particles can be explained by binary nucleation and growth (condensation and coagulation) of H2SO4 and H2O

Temporal interactions facilitate endemicity in the susceptible-infected-susceptible epidemic model

Data of physical contacts and face-to-face communications suggest temporally varying networks as the media on which infections take place among humans and animals. Epidemic processes on temporal networks are complicated by complexity of both network structure and temporal dimensions. Theoretical approaches are much needed for identifying key factors that affect dynamics of epidemics. In particular, what factors make some temporal networks stronger media of infection than other temporal networks is under debate. We develop a theory to understand the susceptible-infected-susceptible epidemic model on arbitrary temporal networks, where each contact is used for a finite duration. We show that temporality of networks lessens the epidemic threshold such that infections persist more easily in temporal networks than in their static counterparts. We further show that the Lie commutator bracket of the adjacency matrices at different times is a key determinant of the epidemic threshold in temporal networks. The effect of temporality on the epidemic threshold, which depends on a data set, is approximately predicted by the magnitude of a commutator norm.Comment: 8 figures, 1 tabl

Development of a stochastic model for performance characterization of a PV/VRB microgrid

Photovoltaic (PV) Microgrids have been proven to be a useful technology in providing an environmentally friendly source of energy when compared to the use of fossil fuels. Accurately characterizing the performance of a microgrid system would ensure that the system is appropriately sized to meet electrical loads without a heavy reliance on diesel generators. A microgrid that is sized properly will reduce the cost of diesel fuel, while also reducing the risk of wasting money on an oversized system. A deterministic model which was created to characterize the performance of PV microgrids based on percent of time generator running was modified in order to perform a stochastic Monte Carlo analysis. The analysis used four random variables: global horizontal irradiance (GHI), ambient temperature, vanadium redox battery state of charge (VRB SOC), and energy load. Values for these variables in the model will be generated using PDFs derived from probability plots. Data for GHI and ambient temperature were taken from a TMY3 data set for the microgrid locations. Energy load data was collected over eight months and used to characterize the energy load for one year. The VRB SOC distribution was determined using engineering judgment. Three test methods will be performed on two microgrid systems to predict the performance of each system using stochastic and deterministic methods. --Abstract, page iv

Bruno Taut: el edificio de la facultad de Ankara y el palacio Katsura de Kioto. La idea de la arquitectura en el concierto de culturas

Los viajes de ida y vuelta que Bruno Taut y su esposa realizaron en su huida de la Alemania nazi hacia oriente le permitió adquirir una visión cosmopolita de la arquitectura que pudo plasmar durante su estancia en Japón en un voluminoso tratado, Architekturüberlegungen-Reflexiones sobre la arquitectura, al que luego sumaría Architekturlehre-Enseñar arquitectura

Stress Corrosion Cracking of titanium alloys - SCC of aluminum alloys, polarization of titanium alloys in hydrogen chloride and correlation of titanium and aluminum SCC behavior Quarterly progress report, 1 Oct. 1968 - 31 Mar. 1969

Stress corrosion cracking of titanium alloys and aluminum alloy

Robot-Assisted Minimally Invasive Surgery-Surgical Robotics in the Data Age

Telesurgical robotics, as a technical solution for robot-assisted minimally invasive surgery (RAMIS), has become the first domain within medicosurgical robotics that achieved a true global clinical adoption. Its relative success (still at a low single-digit percentile total market penetration) roots in the particular human-in-the-loop control, in which the trained surgeon is always kept responsible for the clinical outcome achieved by the robot-actuated invasive tools. Nowadays, this paradigm is challenged by the need for improved surgical performance, traceability, and safety reaching beyond the human capabilities. Partially due to the technical complexity and the financial burden, the adoption of telesurgical robotics has not reached its full potential, by far. Apart from the absolutely market-dominating da Vinci surgical system, there are already 60+ emerging RAMIS robot types, out of which 15 have already achieved some form of regulatory clearance. This article aims to connect the technological advancement with the principles of commercialization, particularly looking at engineering components that are under development and have the potential to bring significant advantages to the clinical practice. Current RAMIS robots often do not exceed the functionalities deriving from their mechatronics, due to the lack of data-driven assistance and smart human–machine collaboration. Computer assistance is gradually gaining more significance within emerging RAMIS systems. Enhanced manipulation capabilities, refined sensors, advanced vision, task-level automation, smart safety features, and data integration mark together the inception of a new era in telesurgical robotics, infiltrated by machine learning (ML) and artificial intelligence (AI) solutions. Observing other domains, it is definite that a key requirement of a robust AI is the good quality data, derived from proper data acquisition and sharing to allow building solutions in real time based on ML. Emerging RAMIS technologies are reviewed both in a historical and a future perspective

Spheroidisation of metal powder by pulsed electron beam irradiation

A new powder spheroidisation process has been demonstrated using a large-area, pulsed electron beam technique. This was used to dramatically improve the surface morphology of Stellite 6 metal powder. Powder surface asperities up to 20 μm size can be eliminated by melting and incorporation into the near-surface of the particle. Surface finish is significantly improved. Agitation and rotation of particles due to a beam-induced stress wave enables the irradiation of multiples sides of particles, resulting in uniformly smoothed particles after sufficient pulses. Elemental analysis revealed no measurable contamination as a result of the process. Transmission electron microscopy showed a dense layer is produced within a zone up to 3 μm beneath the surface, with a substantially reduced grain size from ca. 2 μm diameter in the bulk to ca. 40 nm. Elemental homogenisation also was accompanied by grain refinement. The irradiated Stellite 6 showed a reduced basic flowability energy (583 mJ compared to 627 mJ for the untreated), explained by reduced particle-particle cohesion and interlocking, and an increased conditioned bulk density of 4.57 g/ml compared to 4.33 g/ml due to satellite/asperity reduction

Functional expression of TLR5 of different vertebrate species and diversification in intestinal pathogen recognition

Toll-like receptor 5 (TLR5) is activated by bacterial flagellins and plays a crucial role in the first-line defence against pathogenic bacteria and in immune homeostasis, and is highly conserved in vertebrate species. However, little comparative information is available on TLR5 functionality. In this study, we compared TLR5 activation using full-length and chimeric TLR5 of various vertebrate species (human, chicken, mouse, pig, cattle). Chimeric TLR5 receptors, consisting of human transmembrane and intracellular domains, linked to extracellular domains of animal origin, were generated and expressed. The comparison of chimeric TLR5s and their full-length counterparts revealed significant functional disparities. While porcine and chicken full-length TLR5s showed a strongly reduced functionality in human cells, all chimeric receptors were functional when challenged with TLR5 ligand Salmonella FliC. Using chimeric receptors as a tool allowed for the identification of ectodomain-dependent activation potential and partially host species-specific differences in response to various enteric bacterial strains and their purified flagellins. We conclude that both the extra- and intracellular determinants of TLR5 receptors are crucial for compatibility with the species expression background and hence for proper receptor functionality. TLR5 receptors with a common intracellular domain provide a useful system to investigate bacteria- and host-specific differences in receptor activation

Dominant g(9/2)^2 neutron configuration in the 4+1 state of 68Zn based on new g factor measurements

The $g$ factor of the $4_1^+$ state in $^{68}$Zn has been remeasured with improved energy resolution of the detectors used. The value obtained is consistent with the previous result of a negative $g$ factor thus confirming the dominant $0g_{9/2}$ neutron nature of the $4_1^+$ state. In addition, the accuracy of the $g$ factors of the $2_1^+$, $2_2^+$ and $3_1^-$ states has been improved an d their lifetimes were well reproduced. New large-scale shell model calculations based on a $^{56}$Ni core and an $0f_{5/2}1pg_{9/2}$ model space yield a theoretical value, $g(4_1^+) = +0.008$. Although the calculated value is small, it cannot fully explain the experimental value, $g(4_1^+) = -0.37(17)$. The magnitude of the deduced B(E2) of the $4_1^+$ and $2_1^+$ transition is, however, rather well described. These results demonstrate again the importance of $g$ factor measurements for nuclear structure determination s due to their specific sensitivity to detailed proton and neutron components in the nuclear wave functions.Comment: 7 pages, 3 figs, submitted to PL