Fabrication and investigation of ultravialet Au-Zn<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Cd<Subscript>1–<Emphasis Type="Italic">x</Emphasis></Subscript>S-Mo-structures

For the first time fabricated and investigated the photovoltaic characteristics of Au-Zn _x Cd_1–x S-Mofilm structural injection photo detectors sensitive to narrow the ultraviolet region of the electromagnetic spectrum, based on polycrystalline Zn _x Cd_1–x S layers. It was found by adjusting the flow of ZnS and CdS coming to the surface Mo substrate can control the shape of the spectral sensitivity of the Au-Zn _x Cd_1–x S-Mo-film structural injection photo detectors. The results will allow to optimize the structure of photo detectors and solar cells based on polycrystalline thin film solar cells.     

High-efficiency UV photocells based on Zn<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Cd<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>S solid solutions

A procedure for generating UV photocells in the spectral band Δλ = 350–520 nm with internal amplification is presented. It is revealed that such photocells are characterized by a spectral sensitivity of S _λ ≈ 1.3 A/W at a spectral maximum (λ_max = 461 nm) and by an integral sensitivity of S _int ≈ (25–30) A/lm, which is higher by thousand times than similar parameters of common UV cells. It is shown that photocells based on Zn _x Cd_{1 − x} S solid solutions used as a part of a cascade photo converter make it possible to increase significantly the cascade photo converter efficiency with respect to the existing Si and CdTe photocells.     

Influence of gamma radiation on spectral photosensitivity of (Si<Subscript>2</Subscript>)<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript> (ZnSe)<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> solid solution

Increase of the photosensitivity of the pSi-n(Si₂)_{1 ? x} (ZnSe) _x (0 ≤ x ≤ 0.01) structure exposed to gamma radiation with photon energy E _ph ≥ 2.3 eV has been demonstrated. It is shown that irradiation with dose up to 10⁴ rad raises and radiation with dose up to 10⁵ rad reduces the forward current of the pSi-n(Si₂)_{1 ? x} (ZnSe) _x structure.     

The composition dependence of the effective thickness of the base layer in Al<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Ga<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>P/GaP heterophotoconverters

The dependence between the composition of Al _x Ga_{1 − x} P heterophotoconverters and the effective thickness of their base layers was established. An empirical formula to estimate the effective thickness of a base layer as a function of the composition of solid-state solution (0 ≤ x ≤ 0.8) was proposed.     

Output Feedback Robust <Emphasis Type="Italic">H</Emphasis>∞ Control with <Emphasis Type="Italic">D</Emphasis>-Stability and Variance Constraints: Parametrization Approach

In this paper, we study the problem of robust H controller design for uncertain continuous-time systems with variance and D-stability constraints. The parameter uncertainties are allowed to be unstructured but norm-bounded. The aim of this problem is the design of an output feedback controller such that, for all admissible uncertainties, the closed-loop poles be placed within a specified disk, the H norm bound constraint on the disturbance rejection attenuation be guaranteed, and the steady-state variance for each state of the closed-loop system be no more than the prescribed individual upper bound, simultaneously. A parametric design method is exploited to solve the problem addressed. Sufficient conditions for the existence of the desired controllers are derived by using the generalized inverse theory. The analytical expression of the set of desired controllers is also presented. It is shown that the obtained results can be readily extended to the dynamic output feedback case and the discrete-time case.2000 Mathematics Subject Classification. 93E15, 93B36, 93B55.This work was partially supported by the EPSRC under Grant GR/S27658/01, the Nuffield Foundation under Grant NAL/00630/G, and the Alexander von Humboldt Foundation of Germany.     

On Symmetries in Time Optimal Control,Sub-Riemannian Geometries,and the <Emphasis Type="Italic">K</Emphasis>−<Emphasis Type="Italic">P</Emphasis> Problem

The goal of this paper is to describe a method to solve a class of time optimal control problems which are equivalent to finding the sub-Riemannian minimizing geodesics on a manifold M. In particular, we assume that the manifold M is acted upon by a group G which is a symmetry group for the dynamics. The action of G on M is proper but not necessarily free. As a consequence, the orbit space M/G is not necessarily a manifold but it presents the more general structure of a stratified space. The main ingredients of the method are a reduction of the problem to the orbit space M/G and an analysis of the reachable sets on this space. We give general results relating the stratified structure of the orbit space, and its decomposition into orbit types, with the optimal synthesis. We consider in more detail the case of the so-called K?P problem where the manifold M is itself a Lie group and the group G is determined by a Cartan decomposition of M. In this case, the geodesics can be explicitly calculated and are analytic. As an illustration, we apply our method and results to the complete optimal synthesis on S O(3).     

On the possibility of applying <Emphasis Type="Italic">n</Emphasis>/(3C-SiC)–<Emphasis Type="Italic">p</Emphasis>/C<Subscript>DIAMOND</Subscript> white glow heterostructures with improved parameters in illumination systems with power consumption from solar radiation

The voltage-current characteristics and electroluminescence of a light-emitting-diode (LED) n/(3C-SiC)–p/ C_DIAMOND heterostructure with white glow without phosphor created on the basis of diamond film grown by the CVD method on n/(3C-SiC) substrates with a doped level of (5–8) × 10¹⁷ cm^–3 are considered It is shown the possibility to improve the characteristics of created LED structures by their irradiation with a flux of high-energy (5 MeV) electrons of a certain dose and heat treatment.     

Approximate Controllability of Fractional Semilinear Stochastic System of Order <Emphasis Type="Italic">α</Emphasis>∈ (1,2]

A family of dynamical control systems described by nonlinear fractional of order (1,2] stochastic differential equations in L _p spaces is considered. We discussed the approximate controllability of stochastic semilinear fractional control system of order α∈(1,2] under the assumption that the corresponding linear system is approximately controllable. A new set of sufficient conditions for approximate controllability of system are obtained by the theory of strongly continuous α-order cosine family, fixed point theorem, and stochastic analysis techniques. At the end, an example is given to illustrate the theory.     

Adjoint Orbits of <Emphasis Type="Italic">sl</Emphasis>(2, ℝ) on Real Simple Lie Algebras and Controllability

This paper shows that for any Lie group G whose Lie algebra L is the split real form of a complex simple Lie algebra, and for any arbitrary root α, there exists a Cartan decomposition of L, related to α, which characterizes some controllability properties by using the adjoint orbits of sl(2, ?). For a class of invariant control systems evolving on G, it is proved that the necessary full rank condition for controllability is also sufficient.     

Properties of tandem-junction heterophotoconverters with GaAs <Emphasis Type="Italic">p–n</Emphasis> junctions under exposure by bilaterally concentrated sunlight

Properties of GaAs/Al_xGa_1–xAs heterophotoconverters fabricated on two sides of monocrystal plates from GaP and GaAs under lighting conditions by V-shaped concentrators are described. It it found that, owing to the increased transparency of the photoconverter structure with respect to thermal photons and comparatively low GaP thermal resistance, the temperature increment of the p–n junctions and relative losses of the electrical power are notably lower than for photoconverters of the same structure on the basis of GaAs.     

An <Emphasis Type="Italic">ex post</Emphasis> criticism,based on stakeholders’ preferences,of a residential sector’s energy master plan: the case study of the Sicilian region

Energy master plans are important tools for an effective and sustainable land governance. On the other hand, the stakeholder role in setting priorities for planning energy interventions is dramatically increasing, also in the light of recently issued European directives. The priorities of energy-saving measures of the Sicilian energy and environmental master plan were originally established with the application of typical economic indicators (the cost of saved energy and the cost of avoided pollutant emissions). During the prioritization process, there was a minor contribution from stakeholders who were not directly involved in the priority-setting process but were only asked to express their opinions according to the in-force regulations. Based on more active stakeholder involvement in hierarchizing a given set of actions, as required by the recently issued directives, the University of Palermo, which participated in the development of this master plan, assessed an ex post evaluation of these established economy-based priorities, by means of the application of a multi-criteria decision analysis (MCDA) tool. The resulting changed priorities, which lead to a better policy allocation of the regional budget for energy efficiency in the building sector, confirm the preeminent role played by the stakeholders in the development of energy plans, further supported by a sensitivity analysis.     

Thermodynamic evaluations of solar cooling cogeneration cycle using NaSCN–NH<Subscript>3</Subscript> mixture

The commercial refrigeration and air conditioning consumes more electric power for its operation. The solar vapor absorption refrigeration helps to minimize the electric power usage and it is renewable. Large size of solar collector area is required for producing the standalone power as well as cooling cycle. The integration of power and cooling cycle minimizes the number of components such as heat exchanger, separator and collector area. The main objective of the work is to integrate power and cooling for two outputs with single cycle using NaSCN–NH₃ as working fluid. The advantages of NaSCN–NH₃ are having high pressure and pure ammonia vapor at the exit of the generator. The integrated cycle is made by providing the turbine at the exit of the generator along with superheater. It has three pressures of generator, condensing and sink pressure, which is depending on separator and ambient temperature. At the separator temperature of 150°C with weak solution concentration of 0.30, it produces the cogeneration output of 284.80 kW with cycle and plant thermal efficiency of 0.49 and 0.20 respectively.     

Response to: “Evaluating energy efficiency policy: understanding the ‘energy policy epistemology’ may explain the lack of demand for randomized controlled trials,” by Adam Cooper, <Emphasis Type="Italic">Energy Efficiency</Emphasis>, published online 26 January 2018

In January 2018, Adam Cooper (Energy Efficiency, 2018) published a paper that principally responds to a paper by Vine et al. (Energy Efficiency, 7, 627–640, 2014) that makes the case for promoting greater use of experimental research designs, such as randomized controlled trials (RCTs), in the evaluation of energy efficiency policy. Cooper focuses on the barriers that public policy administrators face—arguing that there are alternative, rational reasons why RCTs are not commonly used in energy policy, providing an overlapping but somewhat different “energy policy epistemology” than in Vine (2014).     

Situation and measures of China’s CO<Subscript>2</Subscript> emission mitigation after the Paris Agreement

Global response to climate change has entered the phase of full implementation of the Paris Agreement. To control the global temperature rise below 2°C, all countries must make more efforts to reduce emission. China has combined its goal of emission reduction for combating climate change with its domestic sustainable development strategy to promote energy revolution and the transition of economic development to low-carbon patterns. Through reinforcing the commitment and action before 2020, the CO₂ intensity of GDP can decrease by more than 50% by 2020 compared with that of 2005, and the external commitment target of a 40%–45% decrease can be over fulfilled. Currently, under the new economic normal, China further strengthens the policy measure, vigorously saves energy, enhances energy use efficiency and the economic output benefit, and simultaneously develops new and renewable energy and accelerates energy structural decarbonization, so that the annual decrease rate of the CO₂ intensity of GDP keeps a high level of more than 4% and remains increasing. Thus, the decrease rate of the CO₂ intensity of GDP will exceed the GDP growth rate, and then CO₂ emission will peak around 2030. This will promote the fundamental turning of economic development mode, and lay a foundation for the establishment of a sustainable energy system with near-zero emissions and with new and renewable energy as the main body in the second half of this century. China implements the concept of green low-carbon development and accelerates the low carbon transition of energy and economy to achieve win-win results in economic growth and CO₂ emission mitigation, and these policies and actions will also provide experiences for many other developing countries. On the other hand, China will continue to play a positive and constructive leading role in the implementation of the Paris Agreement internationally, and promote the construction of new mechanisms of win-win cooperation, fairness and justice and common development for global climate governance. Moreover, China will make an effort to build a community of common destiny for mankind, promote pragmatic cooperation among countries, especially among developing countries, and take combating climate change as a new development opportunity for jointly moving toward climate-friendly low-carbon economic development path.     

Which factors drive CO<Subscript>2</Subscript> emissions in EU-15? Decomposition and innovative accounting

This study breaks down carbon emissions into six effects within the 15 European Union countries group (EU-15) and analyses their evolution in four distinct periods: 1995–2000 (before European directive 2001/77/EC), 2001–2004 (after European directive 2001/77/EC and before Kyoto), 2005–2007 (after Kyoto implementation), and 2008–2010 (after Kyoto first stage), to determine which of them had more impact in the intensity of emissions. The complete decomposition technique was used to examine the carbon dioxide (CO₂) emissions and its components: carbon intensity (CI effect); changes in fossil fuels consumption towards total energy consumption (EM effect); changes in energy intensity effect (EG effect); the average renewable capacity productivity (GC effect); the change in capacity of renewable energy per capita (CP effect); and the change in population (P effect). It is shown that in the post Kyoto period there is an even greater differential in the negative changes in CO₂ emissions, which were caused by the negative contribution of the intensity variations of the effects EM, GC, CP and P that exceeded the positive changes occurred in CI and EG effects. It is also important to stress the fluctuations in CO₂ variations before and after Kyoto, turning positive changes to negative changes, especially in France, Italy and Spain, revealing the presence of heterogeneity. Moreover, the positive effect of renewable capacity per capita and the negative effect of renewable capacity productivity are the main factors influencing the reduction in CO₂ emissions during the Kyoto first stage. It is possible to infer from the results that one of the ways to reduce emissions intensity will be by increasing the renewable capacity and the productivity in energy generation and consequently through the reduction of the share of the consumption of fossil fuels.     

Synthesis of TiO<Subscript>2</Subscript> nanoparticle using sol–gel route and testing its photovoltaic performance in dye-sensitized solar cell

In the present work, sol–gel method is used to synthesize TiO₂ nanoparticle. The characterization of the prepared TiO₂ powder is done using Powder X-ray diffraction (powder XRD), Scanning Electron Microscope (SEM), Energy-Dispersive X-Ray Spectroscopy (EDS) and Ultraviolet-Visible Spectrophotometry (UV-Vis). The XRD pattern reveals formation of anatase phase TiO₂. The SEM images reveal agglomeration of nanoparticles. The absorbance spectrum of TiO₂ nanoparticles was observed with excitonic peaks at 327 nm and the band gap came out to be ~3.2 eV. This prepared TiO₂ was tested for photovoltaic performance by using it in the Dye sensitized solar cell (FTO/TiO₂/N719/KI-I₂/Pt). Conversion of solar light energy to electricity was successfully done using this TiO₂. The fabricated cell showed an open-circuit voltage (V _OC) of 587 mV and short-circuit current density (J _SC) of 5.06 mA/cm². Maximum power (P _max) generated was 1.912 mW/cm² with a fill factor (FF) of 0.644 and a conversion efficiency of 1.91%.     

Modeling China’s energy dilemma: conflicts among energy saving,energy security,and CO<Subscript>2</Subscript> mitigation

This study analyzes China’s future energy scenarios stretching until 2050 under different policy portfolios of energy security (e.g., oil import dependency) and CO₂ emissions control. Four scenarios, namely, ① business as usual, ② strong oil import dependency (OID) control, ③ strong CO₂ emissions control, and ④ twofold emphasis on OID and CO₂ emissions control, are designed. The results reveal the existence of conflicts among China’s multiple objectives, particularly energy saving, energy security, and CO₂ mitigation. Based on the analysis, an improvement in China’s efficiency in fossil energy conversion and the promotion of the utilization of non-fossil energy such as nuclear, wind, and hydro energy are recommended. The over-development of coal-derived fuels should also be avoided because of incremental coal consumption and CO₂ emissions. Furthermore, research on and development of carbon capture and storage technologies should be promoted, while the energy efficiency loss caused by integrating these technologies into energy systems should be reduced in view of the high possibility of stricter standards for CO₂ emissions in the future.     

关于出版<余热余压利用技术与案例研究专刊>征稿启事

正为贯彻落实国家及市政府关于推进节能十大工程的要求,在上海市经济和信息化委员会的领导和指导下,上海市节能监察中心、上海市节能协会联合决定"上海节能"杂志编辑出版《余热余压利用     

关于出版<余热余压利用技术与案例研究专刊>征稿启事

正为贯彻落实国家及市政府关于推进节能十大工程的要求,在上海市经济和信息化委员会的领导和指导下,上海市节能监察中心、上海市节能协会联合决定"上海节能"杂志编辑出版《余热余压利用技术与案     

Steam reforming of ethanol into hydrogen-rich gas using microwave Ar/water “tornado” – Type plasma

Microwave plasma steam reforming of ethanol under vortex gas flow and atmospheric pressure conditions has been investigated. The main gas products of the steam reforming are H₂ and CO as detected by mass spectrometry and Fourier transform infrared spectroscopy. A “black” carbon deposit on the wall has been observed. A previously developed theoretical model for ethanol decomposition accounting for the gas thermal balance and the chemical kinetics has been further extended to account for the addition of steam to the argon/ethanol feeding background gas. The mechanisms of ethanol and water decomposition depend on the ethanol/steam ratio, and several hydrogen production regimes have been identified and discussed. An integral reaction scheme for ethanol/water decomposition is suggested.