MRC Laboratory of Molecular Biology
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Demonstration of robust self-referenced continuous variable quantum key distribution over 25km fiber link
No full textWe experimentally demonstrate a practical self-referenced continuous variable quantum key distribution system composed of embedded data conversion/acquisition units and standard telecommunication components over a 25km optical fiber, with a predicted key rate of 649kbps
Truck suspension incorporating inerters to minimise road damage
No full textRoad damage caused by heavy vehicles is a serious problem experienced worldwide. This paper investigates the potential for reduction in road damage by incorporating the inerter element into truck suspension systems. Initially, quarter-car, pitch-plane and roll-plane models with two low-complexity inerter-based linear suspension layouts are investigated in the frequency domain. Reductions of the J95 road damage index for each model are identified against conventional parallel spring–damper truck suspension layouts. It is also shown that the proposed suspensions are capable of enhancing the roll stability while keeping the road damage at a given level. Subsequently, the nonlinear relationship between force and displacement as manifested by leaf springs is incorporated into the pitch-plane and roll-plane time-domain models. These confirm the potential advantage of inerter-based suspension layouts for road damage reduction
Identification of organic species with “double-sided tape” characteristics on the surface of carbonate reservoir rock
No full text© 2020 Elsevier Ltd Carbonate reservoir rocks are normally mixed-wet or oil-wet, leading to low oil recovery efficiency using water-based oil recovery methods. It is critical to understand the molecular composition of the organic material coating the surface of carbonate reservoir rock in order to design better enhanced oil recovery (EOR) methods. Herein, we extracted organic compounds from a carbonate reservoir rock and characterized their composition using high resolution mass spectrometry (HRMS). In contrast to conventional interpretation that the mixed-wet or oil-wet nature of carbonate reservoir rocks arises from the adsorption of carboxylic acids, our results demonstrated that the organic species strongly bound to carbonate reservoir rock surface are dominated by N-containing species, including a group of “sticky molecules”. Each of these molecules can form multiple hydrogen-bonds, therefore they might act as a “double-sided tape” which binds crude oil strongly to the carbonate rock surface. Furthermore, we applied atomic force microscopy (AFM) techniques to a model mineral surface with regions of positive change and negative charge which was contacted with the crude oil produced from the formation where the rock was sampled. It was found that only the organic molecules with positive charge in the oil were adsorbed onto the mineral. This supports HRMS results which suggest that the organic materials strongly bound to the carbonate reservoir rock surface are dominated by basic N-containing molecules. Overall, these findings suggest that, beside fatty acids, these “sticky molecules” might also play an important role in controlling the wetting state of carbonate reservoir rock
Evaluation of the repeatability of kinetic and temporospatial gait variables measured with a pressure-sensitive treadmill for dogs.
No full textOBJECTIVE: To evaluate intrasession and intersession repeatability of measurements for temporospatial and kinetic variables obtained with a pressure-sensitive treadmill designed for gait analysis of dogs. ANIMALS: 16 client-owned dogs. PROCEDURES: The influence of treadmill speed on accuracy of ground reaction force (GRF) measurements was assessed by simulated gait analysis at 0 to 7.5 km/h with a custom test device. A similar test was performed with 1 client-owned dog ambulating on the treadmill at 5 speeds (3 to 7 km/h) for GRF calculations. Fifteen client-owned dogs were then walked on the treadmill at 3 km/h for collection of temporospatial and kinetic data. Intrasession repeatability was determined by comparing 2 sets of measurements obtained ≤ 2 hours apart. Intersession repeatability was determined by comparing the first set of these measurements with those for a second session ≥ 4 days later. Intraclass correlation coefficients (ICCs; consistency test) and difference ratios were calculated to assess repeatability. RESULTS: Increases in treadmill speed yielded a mean 9.1% decrease in weight-normalized force data at belt speeds of up to 7.5 km/h for the test device, compared with the value when the treadmill belt was stationary. Results were similar for the dog at increasing treadmill speeds (mean decrease, 12.4%). For temporospatial data, intrasession ICCs were > 0.9 and intersession ICCs ranged from 0.75 to 0.9; for GRFs, intrasession and intersession ICCs ranged from 0.68 to 0.97 and from 0.35 to 0.78, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Repeatability of temporospatial data for healthy dogs was good to excellent; results for kinetic data varied. Further research is needed to investigate use of this system for gait analysis with larger samples of dogs and dogs with lameness
Electric vehicles and batteries as domestic storage units in the united kingdom
No full textThis paper assesses the economic feasibility of Vehicle-to-Home (V2H) and domestic battery systems in the United Kingdom (UK) via calculating the savings by switching to different tariffs. To do the analysis, a UK average Electric Vehicle (EV) and domestic battery have been established; called UKEV and UKBat respectively. The UKEV characteristics were determined by taking a weighted average from the five highest selling EVs in the UK. An arithmetic mean was found for the individual UKBat features from seven models available on the UK market. The UKEV and UKBat were compared under four scenarios. These are Ofgem's two domestic electricity profile classes (PC1, PC2) and two existing time-of-use tariffs; one with two and the other with three rates during a day. At medium battery degradation rate, maximum annual savings for the consumer was estimated to be around £94 and £147 per year for the EV and battery, respectively
Productivity growth and business model innovation
No full textOrganizational factors have been identified as a possible explanation for total factor productivity and hence the Solow paradox. We posit that business model innovation is a major organizational factor. However, there has not been any systematic study on how business model innovation affects productivity growth rates. We introduce a novel approach of measuring business model innovation using change in the net asset turnover ratio. The study shows that business model innovation contributes significantly to productivity growth across firms in the UK between 2003 and 2017. The study provides empirical support that business model innovation could partially explain the Solow productivity paradox
Theoretical investigation on graphene-supported single-atom catalysts for electrochemical CO<inf>2</inf>reduction
No full textWith the advantages of maximum metal utilization, single-atom catalysts (SACs) are emerging as promising catalysts in the CO2 reduction reaction (CO2RR) field. Herein, first-principles calculation is performed to investigate the CO2-to-CO conversion mechanism by a serial of transition metal single transition metal atom supported on graphene systems (TM@Grs) as a CO2 reduction catalyst. Among all SACs considered in this work, Cr@Grs exhibits a low limiting potential of -0.21 V, showing remarkable performance for CO2RR. To understand activity origin of CO2RR, we analyzed the effect of d-band centers of TM@Grs and investigated the charge transfer and bonding/antibonding states between the intermediates and TM atoms. These physical quantities provide a good explanation for the process of CO2RR and show the theoretical guidance for proper catalyst discovery and better carbon circulation. This journal i
Continuous Over-Current Safe Operation Area of SiC MOSFET at Cryogenic and Room Temperatures
No full textThe over-current withstanding capability of silicon carbide (SiC) MOSFET is crucial for short-circuit and over-load fault protections. This paper presents experimental investigations into continuous over-current safe operation area (SOA) of SiC MOSFET at cryogenic and room temperatures. Benefited by high cooling power from cryogenic liquid nitrogen at 77 K, cryogenic operation of SiC MOSFET results in more than 10 times of the over-current withstanding time at room temperature. In view of engineering applications, four over-current-dependent power functions are extracted to depict the operating behaviours of withstanding time and energy dissipation at 77 K and 300 K, respectively. These characterizations lay some empirical bases for exploring some over-current operating and protecting guidelines of high-reliability SiC-based power conversions
Ferroelectric-Ferroelastic Phase Transition in a Nematic Liquid Crystal.
No full textFerroelectric ordering in liquids is a fundamental question of physics. Here, we show that ferroelectric ordering of the molecules causes the formation of recently reported splay nematic liquid-crystalline phase. As shown by dielectric spectroscopy, the transition between the uniaxial and the splay nematic phase has the characteristics of a ferroelectric phase transition, which drives an orientational ferroelastic transition via flexoelectric coupling. The polarity of the splay phase was proven by second harmonic generation imaging, which additionally allowed for determination of the splay modulation period to be of the order of 5-10 microns, also confirmed by polarized optical microscopy. The observations can be quantitatively described by a Landau-de Gennes type of macroscopic theory