Entropy of a non-isolated system

The main contribution of this paper is the derivation rules summarized from existing high-performance inverters with H6-type configuration, which makes novel topologies possible. In addition, a novel high-efficiency single-phase transformerless photovoltaic inverter with hybrid modulation method is also proposed and evaluated as an example. Without input split capacitors, common-mode voltage and leakage current issues in a nonisolated system with H6-type configuration are eliminated, and the feature of a three-level output voltage in the inverter bridge's middle point helps inductors and power quality optimization. The detailed operation principles with hybrid modulation strategy combined with unipolar and bipolar pulsewidth modulation schemes are presented. Experimental results of a 2200VA prototype verify the proposed topology with hybrid modulation method.

Principles and models of biological transport: Morton H. Friedman Springer-Verlag, Berlin, 1986, 260 pages, D.M. 165,-

This paper adopts a parallel system where two three-level neutral-point-clamped (NPC) inverters connect both ac and dc sides directly considering compact size, low cost, simplicity and easy expandability. But there is a potential zero-sequence circulating current (ZSCC), when the space-vector modulation method is used in the non-isolated system, then a control strategy for the ZSCC is present. The balancing problem of the DC-link capacitor voltage is inherent in the NPC inverter, it is solved throug zero-sequence voltage injection. A coordinate control strategy is then proposed to solve the two problems in NPC inverter at the same time. Experimental results validate the developed model and the proposed control scheme.

Security analysis of the “Ping–Pong” quantum communication protocol in the presence of collective-rotation noise

We investigate the quantum dynamics of Two-Level Systems (TLS) in glasses at\nlow temperatures (1 K and below). We study an ensemble of TLSs coupled to\nphonons. By integrating out the phonons within the framework of the\nGorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation, we derive\nanalytically the explicit form of the interactions among TLSs, and of the\ndissipation terms. We find that the unitary dynamics of the system shows clear\nsignatures of Many-Body Localization physics. We study numerically the time\nbehavior of the concurrence, which measures pairwise entanglement also in\nnon-isolated systems, and show that it presents a power-law decay both in the\nabsence and in the presence of dissipation, if the latter is not too large.\nThese features can be ascribed to the strong, long-tailed disorder\ncharacterizing the distributions of the model parameters. Our findings show\nthat assuming ergodicity when discussing TLS physics might not be justified for\nall kinds of experiments on low-temperature glasses.\n

The Constant Entropy Path for a Chemical Reaction

The exchange-driven growth model describes the mean-field kinetics of a population of composite particles (clusters) subject to pairwise exchange interactions. Exchange in this context means that upon interaction of two clusters, one loses a constituent unit (monomer) and the other gains this unit. Two variants of the exchange-driven growth model appear in applications. They differ in whether clusters of zero size are considered active or passive. In the active case, clusters of size zero can acquire a monomer from clusters of positive size. In the passive case they cannot, meaning that clusters reaching size zero are effectively removed from the system. We show that the large-time behavior is very different for the two variants of the model. We first consider an isolated system. In the passive case, the cluster size distribution tends towards a self-similar evolution and the typical cluster size grows as a power of time. In the active case, we identify a broad class of kernels for which the the cluster size distribution tends to a nontrivial time-independent equilibrium in which the typical cluster size is finite. We next consider a nonisolated system in which monomers are input at a constant rate. In the passive case, the cluster size distribution again attains a self-similar profile in which the typical cluster size grows as a power of time. In the active case, a surprising new behavior is found: the cluster size distribution asymptotes to the same equilibrium profile found in the isolated case but with an amplitude that increases linearly with time.

A very important class of models widely used nowadays to describe and predict, at least in stochastic terms, the behavior of many-particle systems (where the word “particle” is not meant in the purely mechanical sense: particles can be cells of a living tissue, or cars in a traffic flow, or even members of an animal or human population) is the Kinetic Theory for Active Particles, i.e., a scheme of possible generalizations and re-interpretations of the Boltzmann equation. Now, though in the literature on the subject this point is systematically disregarded, this scheme is based on Markov Chains, which are special stochastic processes with important properties they share with many natural processes. This circumstance is here carefully discussed not only to suggest the different ways in which Markov Chains can intervene in equations describing the stochastic behavior of any many-particle system, but also, as a preliminary methodological step, to point out the way in which the notion of a Markov Chain can be suitably generalized to this aim. As a final result of the discussion, we find how to develop new very plausible and likely ways to take into account possible effects of the external world on a non-isolated many-particle system, with particular attention paid to socio-economic problems.

Solar energy is one of the main types of clean and renewable energy. The scale of the photovoltaic (PV) plants is growing rapidly worldwide. Since the PV facilities are vulnerable to lightning strikes, appropriate lightning surge analysis is necessary before the power plant is constructed. The finite-difference time-domain (FDTD) method is one of the suitable ways for analyzing transient surge behaviors. With adopting an improved thin wire model, the PV frames can be simulated accurately and conveniently in the time domain analysis. In this paper, a lightning surge analysis in a photovoltaic system under a direct lightning strike based on the FDTD method. A non-isolated lightning protection system is adopted. The surge voltages between the PV frames and the negative DC cables are measured and discussed.

On time evolution of non-isolated physical systems

We discuss the problem of the generalization of Bell local hidden variable models for unstable particles as nucleons or decaying quantum bound states. We propose to extend the formalism of real deterministic hidden variables in the complex domain, in analogy with the quantum Gamow ket formalism, and we introduce a time dependent classical probability density distribution by which we implement hidden time dependence in the quantum expectation values. We suggest therefore a classical framework which may recover by asymptotic temporal limits the standard Bell stationary quantum statistical averages. Endly we discuss the possible relevance of our proposal for general non-isolated quantum systems in noninertial frames and the consequent dynamic effects of vacuum instabilities on E.P.R tests and Q.M. ensemble statistical averages.

What is the best way to consider energy in buildings? For over a century, the building industry has largely focused on ideas of insulation and isolation for its energetic practices. A growing movement of designers claim that other concepts and practices are required for the non-isolated energy systems of architecture. This book describes the history, theory and facts of the mainstream isolation technologies and the emerging alternative design approaches. It is a book on the scientific, material, and design history of building isolation; but more importantly, it is a book on isolated and non-isolated perspectives on energy in architecture. Written by a registered practicing architect with detailed technical knowledge, who is at the same time a researcher and experienced teacher, the aim is to understand the different scientific, architectural and cultural approaches to energy and to promote a non-isolated perspective: a thermodynamically accurate, ecologically powerful, culturally relevant, and architecturally ambitious perspective on energy in architecture.

Nonisolated three-phase AC/DC converter concepts facilitate more compact and more efficient realizations of future electric vehicle (EV) chargers. However, without the galvanic isolation and/or high common-mode (CM) impedance provided by an isolation transformer, nonisolated chargers must employ other means to suppress CM leakage currents to ground sufficiently and to prevent nuisance tripping of mandatory residual current devices (RCDs). Typically, the required electromagnetic interference (EMI) filters reduce high-frequency (HF) CM leakage currents to uncritical values. However, low-frequency (LF) CM voltages, e.g., generated by third-harmonic injection, may drive significant LF CM currents through the parasitic capacitances of the DC output (including the battery pack) to protective earth (PE). Therefore, considering a nonisolated three-phase buck–boost (bB) current DC-link PFC rectifier system that consists of a buck-type current-source rectifier (CSR) stage and a three-level boost-type DC/DC-stage, this article first proposes a virtual grounding control (VGC) of the DC output voltage midpoint. VGC employs the DC/DC-stage to compensate the LF (third-harmonic) CM voltage inherently generated by the CSR-stage and thus controls the LF CM voltage between the DC output midpoint and PE to zero. This enables further a direct connection of the DC output midpoint to PE, where an additionally proposed ground current control (GCC) ensures near-zero LF CM leakage current. The proposed concepts are verified with a 10-kW hardware demonstrator (power density of 6.4 kW/dm 3 or 107.5 W/in 3 and full-load peak efficiency of 98.5%) considering terra–terra (TT) and terra–neutral (TN) grounding systems. With a direct connection of the DC output midpoint to PE, GCC limits the LF CM leakage current to < 6 mA RMS, i.e., significantly below typical RCD trip levels, and, using the human-body impedance model according to UL 2202, achieves a test voltage of 110 mV that is clearly below the most stringent limit (250 mV) of the standard.

In recent years, due to various environmental protection policies and the popularity of new energy sources, photovoltaic power generation has been strongly encouraged and developed at home and abroad. Suppressing leakage current is a key issue for non-isolated PV grid-connected systems. This paper analyzes various circuit topologies proposed to suppress the leakage current based on the bridge structure. This paper will compare and analyze the representative circuit topologies among them, comparing their circuit diagrams, operating principles, pros and cons, and so on. The leakage current can be effectively suppressed by bipolar modulation, but it will produce great electromagnetic noise and full harmonic distortion, reducing system efficiency. The HERIC circuit has the highest conversion efficiency and the best leakage current suppression effect among the three half-bridge structures and three full-bridge structures summarized in this paper. By summarizing and comparing, future research efficiency will improve when similar problems arise.

This paper presents control strategy for multifunctional, three-phase, four wire AC-DC converters. The converter is named multifunctional because it operates as a battery charger and as a load power supply. In other words, two different loads in parallel are connected simultaneously to the converter. For this purpose same current and voltage signals are necessary to send to the control circuit. The indicated signals are, input main currents, output load currents, battery bank currents, voltage across of each battery bank, total output voltage, and input main voltages for feed-forward networks and current shape. The proposed converter control strategy is applied in non-isolated three-phase UPS systems. The relevant features of the proposed converter control strategy are, power factor correction, common neutral point between input and output to facilitate bypass circuit installation, symmetrical divided output voltage for inverters with neutral point, and battery current control with high power factor. Principle of operation of the control circuit and experimental results obtained from a small power scale prototype are presented.