Quantum correlations and thermodynamic performances of two-qubit engines with local and collective baths

We investigate heat engines whose working substance is made of two coupled qubits performing a generalised Otto cycle by varying their applied magnetic field or their interaction strength during the compression and expansion strokes. During the heating and cooling strokes, the two qubits are coupled to local and common environments that are not necessarily at equilibrium. We find instances of quantum engines coupled to non equilibrium common environments exhibiting non-trivial connections to quantum correlations as witnessed by a monotonic dependence of the work produced on quantum discord and entanglement.Comment: Close to published versio

Motion estimation of objects in KC-135 microgravity

The simulated microgravity environment aboard a KC-135 aircraft flying along a parabolic trajectory was used to study the ability of an autonomous space robot to grasp a freely translating and rotating object. Since the KC-135 cabin environment and the instrumentation for the Extravehicular Activity Helper/Retriever (EVAHR) do not provide a practical intertial reference frame, estimators based on the extended Kalman filter algorithm were used to model the relative translational dynamics of the KC-135 and the EVAHR. The estimator algorithms require intensive mathematical computation and therefore, i860 real-time. Estimator design, implementation concerns, and issues specific to the KC-135 environment are discussed and the architecture of the KC-135 translational state estimator is depicted

Jody Hewgill

A portfolio of work by illustrator Jody Hewgill. More information is available at www.jodyhewgill.com

Open Source Quantitative Stress Prediction Leveraging Wearable Sensing and Machine Learning Methods

The ability to monitor physiological parameters in an individual is paramount for the evaluation of physical health and the detection of many ailments. Wearable technologies are being introduced on a widening scale to address the absence of low-cost and non-invasive health monitoring as compared to medical grade equipment and technologies. By leveraging wearable technologies to supplement or replace traditional gold-standard measurement techniques, the research community can develop a deeper multifaceted understanding of the relationship between specific physiological parameters and particular health conditions. One particular research area in which wearable technologies are beginning to see application is the quantification of physical and mental stress levels in individuals through brainwave and physiological feature monitoring. At present, these methods are time consuming, invasive, expensive, or some combination of the three. This thesis chronicles the development and application of a novel open source wearable sensing platform to the field of stress and fatigue estimation and quantization. More specifically, the garment in its current configuration monitors heart rate, blood oxygen saturation, skin temperature, respiration rate, and skin conductivity parameters to explore the relationship between these parameters and various self-reported stress measures. Utilizing machine-learning methods, subject-specific models were generated in an n=1 study which predicts the self-perceived stress level of the subject with an accuracy of between 92% and 100%. The garment was developed with a modular interface and open source code base to allow and encourage reconfiguration and customization of the sensor array for other research applications. The dataset generated in this effort spans the early stages of the COVID-19 pandemic as the subject experienced increasing levels of isolation and tracks physiological parameters across two months via daily measurements

3,3′-Di-tert-butyl-5,5′-dimethoxy­biphenyl-2,2′-diol

The title compound, C22H30O4, displays twofold rotational symmetry. The two benzene rings are almost perpendicular to each other, forming a dihedral angle of 89.8 (6)°. In the crystal, mol­ecules are linked into an extended one-dimensional chain structure via inter­molecular O—H⋯O hydrogen bonds

Reconciliation of quantum local master equations with thermodynamics

The study of open quantum systems often relies on approximate master equations derived under the assumptions of weak coupling to the environment. However when the system is made of several interacting subsystems such a derivation is in many cases very hard. An alternative method, employed especially in the modelling of transport in mesoscopic systems, consists in using {\it local} master equations containing Lindblad operators acting locally only on the corresponding subsystem. It has been shown that this approach however generates inconsistencies with the laws of thermodynamics. In this paper we demonstrate that using a microscopic model of local master equations based on repeated collisions all thermodynamic inconsistencies can be resolved by correctly taking into account the breaking of global detailed balance related to the work cost of maintaining the collisions. We provide examples based on a chain of quantum harmonic oscillators whose ends are connected to thermal reservoirs at different temperatures. We prove that this system behaves precisely as a quantum heat engine or refrigerator, with properties that are fully consistent with basic thermodynamics.Comment: Published versio

ニホンゴキョウイク ニ オケル ドラマテキアプローチ ノ カノウセイ ニ ツイテ ヒラタ オリザ 「トウキョウノート」ヲ ニホンゴカイワコウザ デ ツカッテミテ

本稿は日本語教育とくに日本語コミュニケーションにおける演劇的アプローチの可能性について論ずる。FitzGibbon(1993)が述べるように、外国語のクラスにおいてドラマの持つ有効性は数多い。1)学習(target)言語を用いて、意味のある、流れのあるインターアクションが生まれやすいこと; 2)音声、韻律上の特徴が断片的でなく、インターアクティブでコンテクストのある場面で学べること; 3)新出語彙、表現が断片的でなく、意味のあるコンテクストの中で学べること; 4)学習(target)言語を習得する上で自信が生まれること等が挙げられる。本稿の目的は3点ある。第一の目的は、中級から上級レベルの日本語学習者にとって、日本語の演劇を主教材としてドラマ的要素を取り入れた日本語コミュニケーション指導法が持つ有効性について検討することである。第二の目的は劇作家平田オリザ作の演劇を実際に日本語の授業で使用して、どのような結果が出たかを報告することにある。第三の目的はこの演劇パフォーマンスをビデオにしたものを基に日本語教材を開発した際の技術的側面について述べることにある。This paper attempts to shed light on drama as a potentially effective method for teaching Japanese, particularly communication skills. As eloquently summarized by FitzGibbons (1993), benefits of drama in the language teaching classroom are numerous: 1) “the acquisition of meaningful, fluent interaction in the target language; 2) the assimilation of phonetic and prosodic features in a contextualized and interactive manner; 3) the fully contextualized acquisition of new vocabulary and expression; 4) a sense of confidence in the learner’s ability to learn the target language. The purpose of this paper is three-fold: 1) to explore the potential benefits of using a Japanese-language play as a learning resource for communicative development for intermediate and advanced learners of Japanese; 2) to discuss the outcomes of the use of a Japanese- language play written by Hirata Oriza; 3) to discuss the technological implications of developing a CD-Rom based on the dramatization of the play by professional actors

O2 mass transfer in an oscillatory flow reactor provided with smooth periodic constrictions : individual characterization of kL and a

In the present work the superficial gas velocities ( u G ) and the oscillatory conditions (frequency and amplitude) effects on the gas–liquid mass transfer process in a novel oscillatory flow reactor provided with smooth periodic constrictions (OFR-SPC) are experimentally evaluated. The liquid-side mass transfer coefficient, k L , and the specific interfacial area, a, are studied individually. The specific interfacial area is obtained using the new automatic image analysis technique developed by Ferreira et al. (2012). The experimental results of volumetric liquid side mass transfer coefficient ( k L a ), Sauter mean diameter ( d 32 ) and gas holdup ( ε G ), and the calculated values of a and k L , are correlated with the superficial gas velocity and the power density ( P / V ), in order to be used in scale-up processes and in comparisons with the literature. The results show that k L a increases with both superficial gas velocity and oscillatory conditions, the last ones having the highest impact on the mass transfer process. The increase in the oscillation motion (frequency and amplitude) results in bubble size reduction (from ∼7 mm, without oscillation, to ∼1 mm, with oscillation), in bubble average residence time increase and, consequently, in a increase. A k L increase with d 32 decrease is observed, showing the importance of hydrodynamic phenomena on k L , specially, when very low bubbles sizes are presented in oscillatory flow reactors.This work was supported by Fundacao para a Ciencia e Tecnologia under program contract number SFRH/BPD/45637/2008

Enhanced gas-liquid mass transfer of an oscillatory constricted-tubular reactor

The mass transfer performance has been tested for gas-liquid flow in a new tubular reactor system, the oscillating mesotube (OMT), which features the oscillatory movement of fluid across a series of smooth constrictions located periodically along the vertical 4.4 mm internal diameter tube. The effect of the fluid oscillations (frequency,f, and center-to-peak amplitude, x(0), in the range of 0-20 s(-1) and 0-3 mm, respectively) on the overall volumetric mass transfer coefficient (k(L)a) has been tested by measuring the oxygen saturation levels with a fiber-optical microprobe (oxygen micro-optrode), and a mathematical model has been produced to describe the oxygen mass transport in the OMT. The oxygen mass transfer rates were about I order of magnitude higher (k(L)a values up to 0.16 s(-1)) than those values reported for gas-liquid contacting in a 50 mm internal diameter oscillatory flow reactor (OFR), for the same peak fluid oscillatory velocity, i.e., 2 pi fx(0). This represents remarkable oxygen transfer efficiencies, especially when considering the very low mean superficial gas velocity involved in this work (0.37 mm s(-1)). The narrower constrictions helped to increase the gas fraction (holdup) by reducing the rise velocity of the bubbles. However, the extent of radial mixing and the detachment of vortex rings from the surface of the periodic constrictions are actually the main causes of bubbles retention and effective gas-liquid contacting and are, thus, responsible for the enhancement of k(L)a in the OMT.N.R. thanks the Portuguese Foundation for Science and Technology (FCT) for financial support of his work (SFRH/BD/6954/2001)