Physically-Realizable Uniform Temperature Boundary Condition Specification on a Wall of an Enclosure: Part I – Problem Investigation

Designing an experimental apparatus requires considerable amount of planning. Despite proper planning, one can easily overlook a design such as the standard uniform temperature boundary condition applied to all or portion of a wall of an experimental apparatus. Although this boundary condition is mathematically simple and precise, achieving it physically may not be that simple. This paper addresses one such three-dimensional natural convection heat transfer apparatus that was designed to measure benchmark Nusselt numbers at various Rayleigh numbers with uniform temperatures specified at two walls of the enclosure. It was found that the effect of thermal spreading/constriction resistance on one wall where this uniform temperature condition was prescribed was significant, and as a result, the uniform temperature profile based on the initial design was not physically achieved. In support of this non-uniform temperature observation, this paper presents a thermal resistance model of a plate (which is a portion of this overall heat transfer apparatus) to explain the observed temperature non-uniformity. The results obtained from the current model are validated with measured data, and in terms of a temperature difference between two locations on the plate, the approximate analytical solution is well within the experimental error of 0.03K

Physically-Realizable Uniform Temperature Boundary Condition Specification on a Wall of an Enclosure: Part II – Problem Solution

Temperature measurements along one side of the rectangular plate showed severe temperature non-uniformity along one side of a wall of a cubical experimental apparatus where the uniform temperature was physically desired. Despite proper planning and analyses, this non-uniformity was high enough that a benchmark study could not be carried out to the desired accuracy of about one percent error. This paper presents and extends analyses made previously based on the modifications to the original design of the apparatus to reduce the temperature non-uniformity on the wall by adding an auxiliary heater around a wall where the uniform temperature was desired. A detailed mathematical analysis shows significant reduction in temperature non-uniformity from about four percent (based on the initial design) to less than one percent (for the modified design). By examining the temperature difference between two locations on the plate, the predicted temperature difference obtained through mathematical analyses show excellent agreement with the measured temperature difference. The temperature non-uniformity along the boundary of a wall was reduced to less than one percent of the overall temperature difference

EFFECTS OF REHABILITATION ON BACK MUSCLE CONTRACTION PATTERNS OF LOW BACK PAIN PATIENTS

The aims of this study were to conduct a comparative investigation of muscle function between low back pain (LBP) patients and normal subjects, as well as to explore whether intensive rehabilitation can change back muscle contraction synergy. 20 normal subjects and 20 patients with chronic LBP were asked to perform symmetrical and asymmetrical tasks. LBP patients were tested in the weeks immediately before and after 12-week LBP rehabilitation treatment. Tasks include “carrying” weights up and down with a 45° left rotation. Eight channel surface EMG electrodes were placed on the surface of paraspinal muscles. correlation between right and left corresponding muscles as well as between pre- and post-treatment were calculated. Lifting capacity for LBP patients were also measured before and after treatment. EMG profiles showed that the muscle activity strategies varied between normal subjects and LBP patients. The correlation coefficients for spinal muscles have shown very reproducible intra-subject muscle contraction synergies. Unbalanced EMG patterns found in LBP patients under symmetrical tasks were not affected by rehabilitation treatment

Synergistic co-cultivation of activated sludge and microalgae in enhancing lipid production and N-laden wastewater treatment

The influence of inoculation ratios of activated sludge and microalgae were investigated in this study in the aspects of biomass yield, lipid yield and total nitrogen (TN) removal efficiency. It was observed that mixed culture of activated sludge/microalgae with the ratio 1:1 and 1:0.75 achieved a maximum lipid production up to 0.144 g/L and 0.133 g/L as compared with microalgae culture alone, which was only 0.081 g/L. The highest total nitrogen (TN) removal was observed with 1:1 and 1:0.75 ratios of activated sludge/microalgae cultures ranging from 96.3-96.9% removal efficiency, which was an improvement of about 90% removal efficiency compared to the activated sludge culture (6.25±0.08%). The flocculation efficiency was generally improved in mixed cultures of activated sludge andmicroalgae in comparison with only activated sludge culture and microalgae culture alone.Keywords: activated sludge; microalgae; co-cultivation; lipid; nitrogen removal

A compact and reconfigurable silicon nitride time-bin entanglement circuit

Photonic chip based time-bin entanglement has attracted significant attention because of its potential for quantum communication and computation. Useful time-bin entanglement systems must be able to generate, manipulate and analyze entangled photons on a photonic chip for stable, scalable and reconfigurable operation. Here we report the first time-bin entanglement photonic chip that integrates time-bin generation, wavelength demultiplexing and entanglement analysis. A two-photon interference fringe with an 88.4% visibility is measured (without subtracting any noise), indicating the high performance of the chip. Our approach, based on a silicon nitride photonic circuit, which combines the low-loss characteristic of silica and tight integration features of silicon, paves the way for scalable real-world quantum information processors.Comment: 4 pages, 5 figure

Repeat-Until-Success quantum computing using stationary and flying qubits

We introduce an architecture for robust and scalable quantum computation using both stationary qubits (e.g. single photon sources made out of trapped atoms, molecules, ions, quantum dots, or defect centers in solids) and flying qubits (e.g. photons). Our scheme solves some of the most pressing problems in existing non-hybrid proposals, which include the difficulty of scaling conventional stationary qubit approaches, and the lack of practical means for storing single photons in linear optics setups. We combine elements of two previous proposals for distributed quantum computing, namely the efficient photon-loss tolerant build up of cluster states by Barrett and Kok [Phys. Rev. A 71, 060310(R) (2005)] with the idea of Repeat-Until-Success (RUS) quantum computing by Lim et al. [Phys. Rev. Lett. 95, 030505 (2005)]. This idea can be used to perform eventually deterministic two-qubit logic gates on spatially separated stationary qubits via photon pair measurements. Under non-ideal conditions, where photon loss is a possibility, the resulting gates can still be used to build graph states for one-way quantum computing. In this paper, we describe the RUS method, present possible experimental realizations, and analyse the generation of graph states.Comment: 14 pages, 7 figures, minor changes, references and a discussion on the effect of photon dark counts adde

A monte-carlo floating-point unit for self-validating arithmetic

Monte-Carlo arithmetic is a form of self-validating arith-metic that accounts for the effect of rounding errors. We have implemented a floating point unit that can perform ei-ther IEEE 754 or Monte-Carlo floating point computation, allowing hardware accelerated validation of results during execution. Experiments show that our approach has a mod-est hardware overhead and allows the propagation of round-ing error to be accurately estimated

Multimodal hyperscanning reveals that synchrony of body and mind are distinct in mother-child dyads

Hyperscanning studies have begun to unravel the brain mechanisms underlying social interaction, indicating a functional role for interpersonal neural synchronization (INS), yet the mechanisms that drive INS are poorly understood. The current study, thus, addresses whether INS is functionally-distinct from synchrony in other systems – specifically the autonomic nervous system and motor behavior. To test this, we used concurrent functional near-infrared spectroscopy - electrocardiography recordings, while N = 34 mother-child and stranger-child dyads engaged in cooperative and competitive tasks. Only in the neural domain was a higher synchrony for mother-child compared to stranger-child dyads observed. Further, autonomic nervous system and neural synchrony were positively related during competition but not during cooperation. These results suggest that synchrony in different behavioral and biological systems may reflect distinct processes. Furthermore, they show that increased mother-child INS is unlikely to be explained solely by shared arousal and behavioral similarities, supporting recent theories that postulate that INS is higher in close relationships