A concept of water usage efficiency to support water reduction in manufacturing industry

Increasing pressures on freshwater supplies, continuity of supply uncertainties, and costs linked to legislative compliance, such as for wastewater treatment, are driving water use reduction up the agenda of manufacturing businesses. A survey is presented of current analysis methods and tools generally available to industry to analyze environmental impact of, and to manage, water use. These include life cycle analysis, water footprinting, strategic planning, water auditing, and process integration. It is identified that the methods surveyed do not provide insight into the operational requirements from individual process steps for water, instead taking such requirements as a given. We argue that such understanding is required for a proactive approach to long-term water usage reduction, in which sustainability is taken into account at the design stage for both process and product. As a first step to achieving this, we propose a concept of water usage efficiency which can be used to evaluate current and proposed processes and products. Three measures of efficiency are defined, supported by a framework of a detailed categorization and representation of water flows within a production system. The calculation of the efficiency measures is illustrated using the example of a tomato sauce production line. Finally, the elements required to create a useable tool based on the efficiency measures are discussed

TESTING THE INCOMPLETE ARBITRATE HYPOTHESIS: EVIDENCE FROM AUSTRALIAN WHOLESALE SUPERANNUATION FUNDS

This paper tests the efficiency of capital markets when information is costly to obtain by analysing the performance of Australian wholesale superannuation funds specialising in the management of domestic equity portfolios from 1991 through 1999. Using a fund regression approach, the paper finds evidence that is consistent with an incomplete arbitrage function, with investment managers generating returns sufficiently high to compensate them for the increased costs of active asset selection. Risk-adjusted returns in the Australian superannuation fund industry, net of management fees and expenses, are comparable to the returns from a passive asset selection policy.Superannuation funds, Australia

A robust sequential hypothesis testing method for brake squeal localisation

This contribution deals with the in situ detection and localisation of brake squeal in an automobile. As brake squeal is emitted from regions known a priori, i.e., near the wheels, the localisation is treated as a hypothesis testing problem. Distributed microphone arrays, situated under the automobile, are used to capture the directional properties of the sound field generated by a squealing brake. The spatial characteristics of the sampled sound field is then used to formulate the hypothesis tests. However, in contrast to standard hypothesis testing approaches of this kind, the propagation environment is complex and time-varying. Coupled with inaccuracies in the knowledge of the sensor and source positions as well as sensor gain mismatches, modelling the sound field is difficult and standard approaches fail in this case. A previously proposed approach implicitly tried to account for such incomplete system knowledge and was based on ad hoc likelihood formulations. The current paper builds upon this approach and proposes a second approach, based on more solid theoretical foundations, that can systematically account for the model uncertainties. Results from tests in a real setting show that the proposed approach is more consistent than the prior state-of-the-art. In both approaches, the tasks of detection and localisation are decoupled for complexity reasons. The localisation (hypothesis testing) is subject to a prior detection of brake squeal and identification of the squeal frequencies. The approaches used for the detection and identification of squeal frequencies are also presented. The paper, further, briefly addresses some practical issues related to array design and placement. (C) 2019 Author(s)

Sensitivity and Linearity of Superconducting Radio-Frequency Single-Electron Transistors: Effects of Quantum Charge Fluctuations

We have investigated the effects of quantum fluctuations of quasiparticles on the operation of superconducting radio-frequency single-electron transistors (RF-SETs) for large values of the quasiparticle cotunneling parameter $\alpha=8E_{J}/E_{c}$, where $E_{J}$ and $E_{c}$ are the Josephson and charging energies. We find that for $\alpha>1$, subgap RF-SET operation is still feasible despite quantum fluctuations that renormalize the SET charging energy and wash out quasiparticle tunneling thresholds. Surprisingly, such RF-SETs show linearity and signal-to-noise ratio superior to those obtained when quantum fluctuations are weak, while still demonstrating excellent charge sensitivity.Comment: Submitted to Phys. Rev. Let

String spectra near some null cosmological singularities

We construct cosmological spacetimes with null Kasner-like singularities as purely gravitational solutions with no other background fields turned on. These can be recast as anisotropic plane-wave spacetimes by coordinate transformations. We analyse string quantization to find the spectrum of string modes in these backgrounds. The classical string modes can be solved for exactly in these time-dependent backgrounds, which enables a detailed study of the near singularity string spectrum, (time-dependent) oscillator masses and wavefunctions. We find that for low lying string modes(finite oscillation number), the classical near-singularity string mode functions are non-divergent for various families of singularities. Furthermore, for any infinitesimal regularization of the vicinity of the singularity, we find a tower of string modes of ultra-high oscillation number which propagate essentially freely in the background. The resulting picture suggests that string interactions are non-negligible near the singularity.Comment: Latex, 30pgs; v2. minor clarifications, references adde

LOW ALTITUDE AIRSHIPS FOR SEAMLESS MOBILE COMMUNICATION IN AIR TRAVEL

The Aviation Administration policy prohibits the use of mobile phones in Aircraft during transition for the reason it may harm their communication system due to Electromagnetic interference. In case the user wants to access cellular network at higher altitudes, base station access is a problem. Large number of channels are allocated to a single user moving at high speed by various Base Stations in the vicinity to service the request requiring more resources. Low Altitude Platforms (LAPs) are provided in the form of Base stations in the Airships with antennas projected upwards which has direct link with the Ground Station. LAPs using LongEndurance Multi-Intelligence Vehicle (LEMVs) equipped with an engine for mobility and stable positioning against rough winds are utilized. This paper proposes a system that allows the passengers to use their mobiles in Aircraft using LAPs as an intermediate system between Aircraft and Ground station. As the Aircraft is dynamic, it has to change its link frequently with the Airships, MANETs using AODV protocol is established in the prototype using NS2 to provide the service and the results are encouraging

Fast tunnel rates in Si/SiGe one-electron single and double quantum dots

We report the fabrication and measurement of one-electron single and double quantum dots with fast tunnel rates in a Si/SiGe heterostructure. Achieving fast tunnel rates in few-electron dots can be challenging, in part due to the large electron effective mass in Si. Using charge sensing, we identify signatures of tunnel rates in and out of the dot that are fast or slow compared to the measurement rate. Such signatures provide a means to calibrate the absolute electron number and verify single electron occupation. Pulsed gate voltage measurements are used to validate the approach.Comment: 4 pages, double column, 3 figure

Single-electron quantum dot in Si/SiGe with integrated charge-sensing

Single-electron occupation is an essential component to measurement and manipulation of spin in quantum dots, capabilities that are important for quantum information processing. Si/SiGe is of interest for semiconductor spin qubits, but single-electron quantum dots have not yet been achieved in this system. We report the fabrication and measurement of a top-gated quantum dot occupied by a single electron in a Si/SiGe heterostructure. Transport through the quantum dot is directly correlated with charge-sensing from an integrated quantum point contact, and this charge-sensing is used to confirm single-electron occupancy in the quantum dot.Comment: 3 pages, 3 figures, accepted version, to appear in Applied Physics Letter

Derandomization of auctions

We study the role of randomization in seller optimal (i.e., profit maximization) auctions. Bayesian optimal auctions (e.g., Myerson, 1981) assume that the valuations of the agents are random draws from a distribution and prior-free optimal auctions either are randomized (e.g., Goldberg et al., 2006) or assume the valuations are randomized (e.g., Segal, 2003). Is randomization fundamental to profit maximization in auctions? Our main result is a general approach to derandomize single-item multi-unit unit-demand auctions while approximately preserving their performance (i.e., revenue). Our general technique is constructive but not computationally tractable. We complement the general result with the explicit and computationally-simple derandomization of a particular auction. Our results are obtained through analogy to hat puzzles that are interesting in their own right