Experimental study of moment sharing in multi-joist timber-concrete composite floors from zero load up to failure

The critical T-sections of multi-joist timber-concrete composite (TCC) floors must be designed at ultimate for support shear force and midspan moment, both of which are influenced by transverse sharing, but to different extents. Prior experimental work has investigated only support reaction sharing and only up to serviceability loads. The present experimental study builds on that status quo by quantifying also moment sharing, via strain gauge layouts at quarter-span and midspan, along with reaction sharing via load cells at the supports of a multi-joist TCC specimen, over the entire load range up to failure. Use of steel mesh connectors bonded into hardwood laminated veneer lumber joists, and near geometric resemblance to a real building TCC floor recently built in London, were novel features of the specimen. The results show that midspan moment and reaction sharing both vary nonlinearly with load, but in distinctly different ways from each other (with up to almost 20% difference observed between them), in the progression between the uncracked, cracked and connection ductility regimes. In this approach reliable assessment of moment sharing depends on the quality of the recorded strains. Accordingly, the strain data were shown to be of high quality by converting these data to internal stress resultants that were then found to satisfy longitudinal equilibrium. It is concluded that this strain gauge layout is useful for future work aimed at building a database of transverse sharing of moments in TCCs

Bacteria as drug delivery vehicles

Doctor of PhilosophyDepartment of Chemical EngineeringStefan H. BossmannBoth chemotherapy for cancer treatment and antibiotic therapy for bacterial infections require systemic applications of the drug and a systemic application is always linked to a number of disadvantages. To circumvent these a targeted drug delivery system was developed. It utilizes the ability of phagocytes from the hosts own immune system to recognize and internalize antigens. Deactivated M. luteus, a non-pathogenic gram positive bacteria was loaded with high concentrations (exceeding the IC50 at least 60 fold in local intracellular concentration) the chemotherapeutics doxorubicin or DP44mt or with the bactericidal chlorhexidine. The modified bacteria is fed to phagocytes (Monocytes/Macrophages or neutrophils) and serves as protective shell for the transporting and targeting phagocyte. The phagocyte is recruited to the tumor site or site of infection and releases the drug along with the processed M. luteus via the exosome pathway upon arrival. The chlorhexidine drug delivery system was successfully tested both in vitro and in vivo, reducing the pathogen count and preventing systemic spread of a F. necrophorum infection in a mouse model. The doxorubicin drug delivery system reduced the viability of 4T1 cancer cells to 20% over the course of four days in vitro

Optimized Pulse Patterns for Anisotropic Synchronous Machines

Advanced optimized pulse patterns (OPPs) that account for the magnetic anisotropy of permanent magnet synchronous motors (PMSMs) have recently gained the attention of the automotive industry due to the improvements they offer in the current quality. However, these improvements can lead to torque quality degradation and an increased dc-link current ripple. To address this problem, a hybrid modulation scheme that combines isotropic and anisotropic OPPs is proposed in this paper to achieve the best overall performance over the whole range of operating points. To do so, as shown with the presented results, different OPPs are assessed and those with the best overall performance are selected.Peer reviewe

Variable Switching Point Predictive Current Control for Multi-Phase Permanent Magnet Synchronous Drives

Finite control set model predictive control (FCS-MPC) is a promising method for the control of multi-phase machines, due to its capability to directly account for nonlinearities and multiple controlled variables. To overcome the drawback of high current ripples and excitation of harmonic currents in the so-called xy-subsystem, several methods have been proposed in the literature so far. This paper proposes an MPC-based method that achieves high granularity of switching by not only switching at the discrete time steps, but also within the sampling interval. In doing so, the discussed algorithm, referred to as variable switching point current control (VSP2CC), produces low current distortions, while still keeping the advantages of conventional FCS-MPC, such as fast dynamic behavior during transients. To highlight the above, VSP2CC is applied to a six-phase permanent magnet synchronous machine (PMSM) and compared with conventional FCS-MPC and MPC that employs virtual voltage vectors (VV-MPC).acceptedVersionPeer reviewe

A hybrid soft solar cell based on the mycobacterial porin MspA linked to a sensitizer-viologen diad

A prototype of a nano solar cell containing the mycobacterial channel protein MspA has been successfully designed. MspA, an octameric transmembrane channel protein from Mycobacterium smegmatis, is one of the most stable proteins known to date. Eight Ruthenium(II) aminophenanthroline-viologen maleimide Diads (Ru-Diads) have been successfully bound to the MspA mutant MspAA96C via cysteine-maleimide bonds. MspA is known to form double layers in which it acts as nanoscopic surfactant. The nanostructured layer that is formed by (Ru-Diad)(8)MspA at the TiO2 electrode is photochemically active. The resulting "protein nano solar cell" features an incident photon conversion efficiency of 1% at 400 nm. This can be regarded as a proof-of-principle that stable proteins can be successfully integrated into the design of solar cells

An Experimental Assessment of Modulation Methods for Drive Trains Used In Electric Vehicles

As the number of electric automotive vehicles is rapidly growing, the need for higher efficiency and system-friendly operation of the drive train becomes more relevant and urgent. In this paper, the synchronous modulation schemes of selective harmonic elimination (SHE) and optimized pulse patterns (OPPs) are described and their performance benefits for drives used in automotive industry are highlighted. The presented experimental results based on an industrial drive demonstrate that OPPs achieve superior performance in terms of current distortions, system efficiency, and dc-link current ripple compared with conventional asynchronous space vector modulation (SVM).acceptedVersionPeer reviewe

Electrochemical activation of molecular nitrogen at the Ir/YSZ interface.

Nitrogen is often used as an inert background atmosphere in solid state studies of electrode and reaction kinetics, of solid state studies of transport phenomena, and in applications e.g. solid oxide fuel cells (SOFC), sensors and membranes. Thus, chemical and electrochemical reactions of oxides related to or with dinitrogen are not supposed and in general not considered. We demonstrate by a steady state electrochemical polarisation experiments complemented with in situphotoelectron spectroscopy (XPS) that at a temperature of 450 °C dinitrogen can be electrochemically activated at the three phase boundary between N2, a metal microelectrode and one of the most widely used solid oxide electrolytes—yttria stabilized zirconia (YSZ)—at potentials more negative than E = −1.25 V. The process is neither related to a reduction of the electrolyte nor to an adsorption process or a purely chemical reaction but is electrochemical in nature. Only at potentials more negative than E = −2 V did new components of Zr 3d and Y 3d signals with a lower formal charge appear, thus indicating electrochemical reduction of the electrolyte matrix. Theoretical model calculations suggest the presence of anionic intermediates with delocalized electrons at the electrode/electrolyte reaction interface. The ex situSIMS analysis confirmed that nitrogen is incorporated and migrates into the electrolyte beneath the electrode

Fluctuating nanomechanical systems in a high finesse optical microcavity

Confining a laser field between two high reflectivity mirrors of a high-finesse cavity can increase the probability of a given cavity photon to be scattered by an atom traversing the confined photon mode. This enhanced coupling between light and atoms is successfully employed in cavity quantum electrodynamics experiments and led to a very prolific research in quantum optics. The idea of extending such experiments to sub-wavelength sized nanomechanical systems has been recently proposed in the context of optical cavity cooling. Here we present an experiment involving a single nanorod consisting of about 10^9 atoms precisely positioned to plunge into the confined mode of a miniature high finesse Fabry-Perot cavity. We show that the optical transmission of the cavity is affected not only by the static position of the nanorod but also by its vibrational fluctuation. While an imprint of the vibration dynamics is directly detected in the optical transmission, back-action of the light field is also anticipated to quench the nanorod Brownian motion. This experiment shows the first step towards optical cavity controlled dynamics of mechanical nanostructures and opens up new perspectives for sensing and manipulation of optomechanical nanosystems.Comment: 16 pages, including 4 figure