bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent advances in catalytic asymmetric dihydroxylation of olefins
Authors: Ottenbacher Roman V. , Talsi Evgenii P. , Bryliakov Konstantin P.
Published: August 2019

Asymmetric dihydroxylation of olefinic groups is an extremely important synthetic transformation which has been widely utilized to obtain optically pure pharmaceuticals and other fine chemical products. In recent years, catalyst systems for the asymmetric C=C dihydroxylations have attracted significant interest, the major research efforts being focused on designing environmentally benign catalyst systems. This mini-review summarizes recent progress in the field, surveying both novel, less toxic modifications of the classical osmium-based catalysts, and the highly efficient and enantioselective non-osmium catalyst systems.

The bibliography includes 50 references.
‘Blinking’ and ‘gliding’ eigenfrequencies of oscillations of elastic bodies with blunted cuspidal sharpenings
Authors: Nazarov S. A.
Published: August 2019

The spectrum of a two-dimensional problem in elasticity theory is investigated for a bodywith a cuspidal sharpening with a short tip of lengththat is broken off. It is known that when the tip is in place, the spectrum of the problem forhas a continuous componentwith positive cut-off point. We show that each pointis a ‘blinking’ eigenvalue, that is, it is an actual eigenvalue of the problem in‘almost periodically’ in the scale of. Among families of eigenvalues, which continuously depend on, we discover ‘gliding’ eigenvalues, which fall down along the real axis at a great rate,, but then land softly on the threshold. This reveals a new way of forming the continuous spectrum of the problem for a cuspidal bodyfrom the system of discrete spectra of the problems in the,. In addition, there may be ‘hardly movable’ eigenvalues, which remain in a small neighbourhood of a fixed point for all small, in contrast to ‘gliding’ eigenvalues.

Bibliography: 30 titles.
Ontogenetic and intraspecific variability in otolith shape of anchoveta (Engraulis ringens) used to identify demographic units in the Pacific Southeast off Chile
Authors: Cerna Francisco , Saavedra-Nievas Juan Carlos , Plaza-Pasten Guido , Niklitschek Edwin , Morales-Nin Beatriz
Published: August 2019

The phenotypical variability in otolith shape of anchoveta (Engraulis ringens) was analysed in three zones (I, II and III) from north to south along the Chilean coast, using juvenile and adult fish. Generalised additive models were used to analyse shape indices and canonical discriminant analysis was used to analyse elliptical Fourier harmonics. The form factor and ellipticity indices varied significantly among the three zones, whereas roundness, circularity and rectangularity indices only showed differences between Zones I and III. Fourier reconstructed outlines for five ontogenetic stages suggested important differences among sampling zones, which were larger for sampling Zone III, where, at the same fish length, otoliths were smaller than those sampled in Zones I and II, at least at the pre-recruit stage. Elliptical Fourier descriptors showed significant differences among the three units, with a total percentage of correct classifications for juveniles of 89 and 74% for raw data and cross-validated cases respectively, compared with >85 and ~65% respectively for adult fish. The results support the hypothesis that juveniles and adults of anchoveta have remained segregated throughout their entire, or at least a fraction of, their life cycle, mainly between the extreme northward and southward zones.
Information Conservation in a Noncommutative Quantum Black Hole Based on Canonical Typicality*
Authors: He Dong-Shan
Published: August 2019

A method for calculating the radiation spectrum of an arbitrary black holes was recently proposed by Ma et al., [Europhys. Lett.
122
(2018) 30001] in which a non-thermal spectrum of a black hole can be obtained from its entropy using an approach based on canonical typicality. The non-thermal spectrum of a black hole enables a nonzero correlation between the black hole and its radiation, which can ensure that information is conserved during black hole evaporation. In this paper, by using the Kantowski-Sachs metric and Feynman-Hibbs procedure, the entropy of a noncommutative quantum black hole is calculated based on the Wheeler-DeWitt equation. Then, the radiation spectrum of the noncommutative quantum black hole is studied based on canonical typicality method. At last, the correlation between the radiation spectra is calculated. It is shown that the noncommutative effect increases the correlation among radiation and the information remains conserved for noncommutative quantum black holes.
Perfect Optical Nonreciprocity with Mechanical Driving in a Three-Mode Optomechanical System*
Authors: Zhao Li-Hua , Li Xian-Li , Lu He-Lin , Tian Xue-Dong
Published: August 2019

Nonreciprocal devices are indispensable for building quantum networks and ubiquitous in modern communication technology. Here, we study perfect optical nonreciprocity in a three-mode optomechanical system with mechanical driving. The scheme relies on the interference between optomechanical interaction and mechanical driving. We find perfect optical nonreciprocity can be achieved even though nonreciprocal phase difference is zero if we drive the system by a mechanical driving with a nonzero phase. We obtain the essential conditions for perfect optical nonreciprocity and analyze properties of the optical nonreciprocal transmission. These results can be used to control optical transmission in quantum information processing.
Aharonov-Bohm Interferometer in a T-Shaped Quantum Dot Embedded in Majorana Bound States*
Authors: Yang Fu-Bin
Published: August 2019

We theoretically study the spin-dependent transport properties of an Aharonov-Bohm (AB) interferometer composed by a T-shaped quantum dot (QD) embedded in Majorana bound states (MBS). We use the equation of motion method to calculate the conductance across the interferometer. We note that the conductance exhibits sensitive dependence on the MBS-QD coupling strength as well as the polarization strength of the leads when the phase factor of AB ring changes periodically. The conductance shows a transition from resonance to anti-resonance when the MBS-QD coupling strength changes from small to large. Also, there is different p-dependence conductance when the leads alignment changes from parallel to anti-parallel. These findings suggest that such a model could be used for a sensitive detection of MBS interactions, exploiting the high sensitivity of conductance to the AB phase in the interferometer.
Physical Properties of Group 14 in P6222 Phase: First-Principles Calculations*
Authors: Zhao Ying-Bo , Zhang Wei , Fan Qing-Yang
Published: August 2019

Two new Group IV element allotropes Si3 and Ge3 in P6222 phase are predicted in this work and their physical properties are investigated using the density functional theory. Each of the newly predicted allotropes has a superdense structure, which is mechanically, dynamically, and thermodynamically stable, as verified by elastic constants, phonon dispersion spectra and relative enthalpies, respectively. The mechanical anisotropy properties are studied in detail by illustrating the directional dependence of Young’s modulus, discussing the universal anisotropic index, and calculating shear anisotropy factors together with bulk moduli. It shows that P6222–Si3 exhibits the greater anisotropy than P6222–Ge3, and interestingly both of the newly predicted crystals appear to be isotropic in the (001) plane. Additionally, the Debye temperature, sound velocities, and the minimum thermal conductivity are examined to evaluate the thermodynamic properties of C3, Si3, and Ge3 in P6222 phase, and the electronic band structures are achieved by HSE06 hybrid functional, which indicate that P6222–C3 and –Si3 are indirect band gap semiconductors and P6222–Ge3 exhibits the metallic feature.
Generalized Hybrid Nanofluid Model with the Application of Fully Developed Mixed Convection Flow in a Vertical Microchannel*
Authors: Xu Hang , Sun Qiang
Published: August 2019

The fully developed mixed convection hybrid nanofluid flow in a vertical microchannel is examined in detail. The simplified hybrid model that omits the nonlinear terms due to the interaction of different nanoparticle volumetric fractions is derived and compared with the existing one. The generalized model describing hybrid nanofluid suspended with multiple kinds of solid particles is suggested. The argument that the corresponding nanofluid solutions obtained by the homogenous model can be recovered from the results of the regular problems through simple arithmetic operations is checked. Solutions in similarity form for this flow problem are formulated by means of a set of similarity variables. The effects of various parameters on important physical quantities are analyzed and discussed.
High-Order Lump-Type Solutions and Their Interaction Solutions to a (3+1)-Dimensional Nonlinear Evolution Equation*
Authors: Fang Tao , Wang Hui , Wang Yun-Hu , Ma Wen-Xiu
Published: August 2019

By means of the Hirota bilinear method and symbolic computation, high-order lump-type solutions and a kind of interaction solutions are presented for a (3+1)-dimensional nonlinear evolution equation. The high-order lump-type solutions of the associated Hirota bilinear equation are presented, which is a kind of positive quartic-quadratic-function solution. At the same time, the interaction solutions can also be obtained, which are linear combination solutions of quartic-quadratic-functions and hyperbolic cosine functions. Physical properties and dynamical structures of two classes of the presented solutions are demonstrated in detail by their graphs.
Resistance Calculation of Pentagonal Lattice Structure of Resistors
Authors: Owaidat M. Q. , Asad J. H.
Published: August 2019

In this study, the effective resistance between any two lattice sites in a two-dimensional pentagonal lattice structure of identical resistors is determined by means of the lattice Green’s function method. Some numerical results of the resistance for small separations between lattice sites are presented.
Optical response of an inverted InAs/GaSb quantum well in an in-plane magnetic field*
Authors: Wu Xiaoguang
Published: August 2019

The optical response of an inverted InAs/GaSb quantum well is studied theoretically. The influence of an in-plane magnetic field that is applied parallel to the quantum well is considered. This in-plane magnetic field will induce a dynamical polarization even when the electric field component of the external optical field is parallel to the quantum well. The electron–electron interaction in the quantum well system will lead to the de-polarization effect. This effect is found to be important and is taken into account in the calculation of the optical response. It is found that the main feature in the frequency dependence of the velocity–velocity correlation function remains when the velocity considered is parallel to the in-plane magnetic field. When the direction of the velocity is perpendicular to the in-plane magnetic field, the de-polarization effect will suppress the oscillatory behavior in the corresponding velocity–velocity correlation function. The in-plane magnetic field can change the band structure of the quantum well drastically from a gapped semiconductor to a no-gapped semi-metal, but it is found that the distribution of the velocity matrix elements or the optical transition matrix elements in the wave vector space has the same two-tadpole topology.
Nano-particle enhancement of diagnosis with Laser-Induced plasma spectroscopy
Authors: Sherbini A M EL , Sherbini A E EL , Parigger C G , Sherbini Th M EL
Published: August 2019

This work discusses nano-particle augmentation of signals in laser-induced plasma spectroscopy. Radiation from a Nd: YAG laser device generates optical breakdown at nano-structured target materials. Extensive scientific investigations of different types of nanomaterial explore dependencies on nanoparticle size, laser wavelength and fluence, and time delay to obtain stronger signals from nano-material than from corresponding solid bulk matter. Modelling of the measurements interprets the occurrence of enhanced detectability of atomic species. Opportunities present themselves for biological and spectrochemical synthesis.
Cancer therapy system based on gold nanoparticle / cold plasma via stimulated singlet oxygen production
Authors: Elgendy Abdelfattah T. , Abdallah Tamer
Published: August 2019

Gold nanoparticles have unique physical/chemical properties which let them very useful in several applications. In addition, to their biocompatibility which is very important for biomedical applications. Recently gold nanoparticles and reactive species of cold plasma have been successfully used for tumor cells and cancer treatment. This method depends on the type of reactive ionized species or the size of gold nanoparticles which it produces and its directed effect on the cell cycle. Our proposed novel designed system which combines both gold nanoparticles and reactive species of nitrogen and argon cold plasma is obtained. Therefore, generating singlet oxygen and reactive species with confirming gold nanoparticles stability as well as to its exposure to cold plasma at different conditions and time periods is accomplished. The analysis of this system will be done using Raman spectroscopy technique. This procedure will enhance better, direct, effective and selective targeting for different kinds of bio-threats such as tumor cells, bacteria, fungi, and virus. This innovative system may be used as a new sterilized technique for different fields such as medical and biological sector, and more promise as cancer therapy selective technique.
Evaluation of the irradiance levels delivered by non-conventional phototherapy devices for intensive Jaundice treatment
Authors: Reda S M , AbdElmaged A A , Monem A S , El-Gebaly R H , Faramawy S M
Published: August 2019

The main purpose of this research is to evaluate irradiance levels delivered by non-conventional phototherapy devices.This evaluation can help to save energy, achieve better treatment and improves available intensive phototherapy quality in use in several hospitals in Egypt. The irradiated energy and uniformity of non-conventional phototherapy devices (n=36) were evaluated at nine hospitals in Egypt. These devices were categorized as three groups including; bilibeds with LEDs, bilibed with fluorescent lamps and bilisphere. The irradiance levels were measured using a phototherapy radiometer. The results show that the irradiance levels ranged from 20.3 to 93.1μW.cm-2.nm-1 and the LEDs bilibed devices produce average irradiance levels approximately double of those results from bilisphere with fluorescent lamps. Otherwise, the bilibed with fluorescent lamps (present about 30 % of the non-conventional phototherapy devices studied) is not adequate for intensive phototherapy. Any assessment of the irradiance energy of the phototherapy devices using a suitable calibrated sensor (radiometer) is mandatory in developing countries. The phototherapy devices that produces an adequate and accurate irradiance levels would increase the degradation rate of bilirubin in the blood and hence minimize the necessity to blood transfusion substitution. LEDs bilibeds produce sufficient electromagnetic energy for jaundice treatment. It can be used alone for intensive treatment better than the bilibed with fluorescent lamps and the bilisphere.
Matter-Antimatter Physics at Low Energy
Authors: Assaad Abdel-Raouf Mohamed
Published: August 2019

The main objective of the present paper is to discuss the consequences of matter-antimatter interaction at low energy. The production of large number of cooled antimatter in laboratory and the formation of exotic atoms composed of particles and antiparticles are reviewed. Particularly, the quantum mechanical treatment of Four-Body exotic molecules is shortly discussed. The main goal of the paper is to shed light on possible novel discoveries and applications based on the coexistence of matter and antimatter.
Prediction of the received global solar irradiance for clear days – simple approach
Authors: Al-Nuaim I A , El-Adawi M K
Published: August 2019

The prediction of the global solar radiation through a distribution function q(t), W/m2 for clear days is given where “t” is the local day time.: The distribution is based on a simple model and is expressed through well-established parameters such as the length of the solar day “td” and the maximum value of the received solar irradiance qmax, w/m2 at time instant “to”.qmax is expressed in terms of the solar constant. Comparison between the computed values of q(t) and the corresponding published experimental data for Hong Kong (China), Valencia( Spain) and Makah (Saudi Arabia) are given as illustrative examples. A test for the degree of fitting is also clarified.
New handling of thermoluminescence glow curve deconvolution expressions for different kinetic orders based on OTOR model
Authors: El-Kinawy Mohamed , El-Nashar Hassan F , El-Faramawy Nabil
Published: August 2019

The exact equations of the thermoluminescence (TL) glow curve deconvolution that describe the intensity of a single TL glow peak of different order kinetics, which are obtained from the one trap-one recombination (OTOR) level model, are considered. The reformulation of the expressions of the intensities of TL glow peaks in terms of the peak intensity IM
, peak position TM
, and the activation energy ∈, for each order of kinetics are achieved. The authors developed a MATLAB computer code, which utilizes the obtained equations, to computationally deconvolute the TL glow curves. The code is used to investigate the reference glow curves of the GLOCANIN program. The obtained results agree with those previously reported by the GLOCANIN project with better values of the figure of merits FOM. The considerations of the obtained equations show promising trends to understand a peak formation for different order kinetics that belong to the OTOR level model.
Dc electric conduction mechanisms and high frequency dielectric properties of different magnetoelectric composites
Authors: Ashmawy M A , Sattar A A , El-Sayed H M , Rashad Mohamed M
Published: August 2019

Various dc conduction mechanisms and high frequency (1MHz up to 3 GHz) dielectric properties have been studied for the particulate and 0-3 core shell composites. X -ray diffraction has been used to identify the structural properties. Tetragonal and cubic structures for PZT and ferrite respectively were appeared either in the pure form or in composites form. The microstructures have been investigated by TEM and particle size distribution was calculated. The microstructure plays a significant role in the electric properties. Dc resistivity vs. temperature measurements were implemented by using ‘two probe’ method. The room temperature resistivity was large in core shell in comparison with composite due to the unique microstructure of the core shell that enhances the interfacial disability of motion of carriers and increasing the carriers hopping path. Moreover, dc electric conduction mechanisms for all investigated samples have been determined. Curie temperatures for ferrimagnetic and ferroelectric phases were the transition points between the conduction mechanisms. Curie temperature of ferrites remarkably increased in the C.S. and composite. Finally, Dielectric and ac resistivity measurements were measured at room temperature. The dielectric constant (ε’) was enlarged in the core shell rather composite while the tangent loss was reduced. These appreciable enhancements could be useful in the high frequency applications.
Structural and ferri-magnetic features of the nano-crystalline Mn0.5CdxSr0.5-xFe2O4 nanoparticles
Authors: Ghoneim A I , Meaz T M
Published: August 2019

Abstract.The as-prepared Mn0.5Cd
x
Sr0.5-x
Fe2O4 nanocrystals, (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5), were synthesized by the one-beaker and smart co-precipitation strategy, thereafter nanocrystals were well-characterized by X-ray diffraction (XRD), FT-IR spectra, higher resolution transmission electrons microscopy (HTEM) and vibrating Nano-samples magnetometry (VSM) strategies. XRD investigation proved the evolution of the single-phase spinel structure for all nano-spinels. The crystallite size R values ranged from 16.05 – to – 32.1 nm, with declining behavior with Cd2+ cationic ratio x. FT-IR absorption spectrum displayed 6-absorption bands that were related to their principle sites and main bonds. The elicited parameters were influenced by the Cd2+ cations replacement instead of Sr2+ cations. Magnetic merits proved the soft-magnetic features for all these nanocrystals, whereas, all the magnetic parameters were influenced by the replacement process with Cd2+ cations. HTEM images exhibited aggregations in these ultrafine nanoparticles. The nanoparticles sizes Z ranged from 20 – to – 35 nm a little greater compared with crystallite sizes R.
Structural, magnetic and electrical properties of nano NiCrxFe2-xO4synthesized by flash auto combustion method
Authors: Henaish A M A , Hemeda O M , Salem B I , El-Sbakhy Fatma S , Khalass Talal
Published: August 2019

The spinel Nano-ferrite system NiCrxFe2-xO4(where x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been prepared using flash auto combustion method. The XRD pattern confirms the formation of spinel Ni-Cr ferrite for the as-prepared samples. Electrical properties of as- prepared samples such dielectric constant and AC resistivity were studied in the temperature range (288- 773 K). It was observed that the AC resistivity increases by increasing Cr content and decreases by increasing frequency. The DC electrical resistivity was found to increase by increasing Cr content from 25*106to 136*106Ω.cm, whereas it was found to decrease with increasing temperature. VSM was used to study the magnetic properties of Ni-Cr ferrite at room temperature. It was found that, with increasing Cr content the (Ms) saturation magnetization decreased from 28 to 3 emu/g whereas coercivity increased from 188 to 666 (G).The magnetic moment of the system and Curie temperature decreased by increasing Cr substitution.
Efficiency enhancement of photovoltaic performance of dye sensitized solar cell using conducting polymer electrolyte of different functional group
Authors: Adel R , Abdallah T , Talaat H
Published: August 2019

Dye-sensitized solar cells (DSSCs) which have a polymer electrolyte added to with various function groups were studied to determine the effect of their composition on the efficiency of the solar cell. Four function group polymers got employed, those groups are polymethylmethacrylate (PMMA), polyvinyl acetate (PVA), polyethylene oxide (PEO) and polyacrylonitrile (PAN). The iodine salt cation is caged by the function groups which cause a positive shift in the dye HOMO level and result in a deceleration in the recombination rate more than that of ordinary iodine electrolyte. The polymer electrolyte ionic conductivity improves the rate of the dye regeneration to make it faster than ordinary iodine as well. Adding pyridine to electrolyte solution makes the conduction band of the TiO2 more negative leading to an increase in the open circuit voltage (Voc). The photo generated current (Jsc) is increased by the employed configureuration, subsequently, the solar cell photovoltaic efficiency is enlarged. PVA is with highest efficiency at 8%, unlike the rest of the polymers which show lower efficiencies.
Effect of barium addition and plasma nitriding treatment on chemical and physical properties of Al, Pb borate glass system as a developed radiation shield
Authors: Saudi H. A. , El Kameesy S. U.
Published: August 2019

The effect of the BaO addition of to aluminum, lead borate in a series of (BaO)x (B2O3)60-x (Al2O3)10 (Li2O)10 (PbO)20 glasses where x = 0 to 50 weight% have been studied through their shielding, mechanical, thermal and chemical properties. The physical parameters such as molar volume (Vm), density (ρ), and oxygen packing density (OPD) were evaluated and discussed. Moreover, the thermal stability of the investigated system increases with BaO content. The present study proved that each of the plasma nitriding treatments of the samples and/or increasing Ba content greatly improved their ability to resist scratching and corrosion. Therefore, the obtained results are candidates for the present glass system to be effectively used as a protective shield against nuclear radiations in many advanced domains.
Comprehensive assessment of advanced solar facade: thermal, optical and economic assessment
Authors: Liang R , Sun Y , Wu Y , Wilson R
Published: August 2019

In order to improve the enegy saving in building, development of glazing system has been widely conducted. CdTe PV window system has the feature of energy generation and adjustment on thermal and visual comfort, in this paper, the thermal performance of a glazing system integrated with semi-transparent CdTe solar cells with different transparency (10% and 50%) under different temperature conditions were investigated by experimental measurement (undertaken in a large climate chamber). The U-value of each PV window has been calculated. Moreover, the spectral transmittance within visible has been measured by spectrometer. This study provided comprehensive fundamental information of different CdTe PV window system for their further investigation on energy and visual comfort.
LCOE analysis of tower CSP plants using different molten salts for TES in China
Authors: Zhuang X R , Xu X H , Liu W R , Liu T L , Xu W F
Published: August 2019

In recent years, Chinese government is vigorously developing concentrating solar power (CSP) technology. It is one of the most promising renewable-based electricity generation technologies to deal with the increasing demand of electricity consumption and environmental sustainability. For the commercialization of CSP technology, low cost is a precondition. However, studies of electricity generation cost analysis for CSP systems, particularly for the tower systems, in China are quite limited. This paper conducts an economic analysis by applying the levelized cost of electricity (LCOE) model for 100 MW tower CSP plants in various locations in China with four different molten salts for thermal energy storage (TES). The results show that it’s inappropriate to build a CSP plant nearby Shenzhen and Shanghai since their LCOEs are higher than 6 RMB kWh−1. There is an optimal capacity of TES resulting in the lowest LCOE for a certain tower CSP plant. And the solar salt has lower LCOE than the other three new molten salts. In order to calculate the time when the grid parity will be reached, four scenarios for CSP development roadmap proposed by International Energy Agency (IEA) are considered in this study. It can be found that the grid parity of tower CSP electricity would be reached in the years of 2038-2041 in the case of no future penalties for the CO2 emissions, and bring forward about 7-14 years when considering the penalties for the CO2 emissions. This research can provide support for government to formulate incentive policies for the CSP industry.
A study of overcast, partly cloudy and clear skies by global illuminance and its variation features
Authors: Lou Siwei , W Li Danny H , Chen Wenqiang
Published: August 2019

The diffuse radiance and luminance distribution in the skydome can determine the solar energy on the building envelope in various orientations and under complex obstructions. The diffuse sky is anisotropic for clear and partly cloudy skies, while isotropic for overcast skies. Thus, identifying the sky conditions are essential to the sky radiance and luminance studies. Previously developed approaches using statistic data suffered from data shortage and inaccuracy. Sunlight under cloudy skies may frequently be blocked, causing the high-frequency illuminance fluctuations. The illuminance should variate smoothly under clear skies without clouds. In this work, we studied the horizontal irradiance time series, its variation frequency, and its relationship to the sky conditions determined by the luminance scan. The work contributes to identifying the sky conditions and skylight distributions using the horizontal global daylight illuminance that is measured by the fixed sensors.
Experimental study on thermal performance improvement of solar air heater using piezoelectric fan
Authors: Jiayu Hu , Chengjun Jin
Published: August 2019

This paper presents experiment research about piezoelectric fan array in solar air heater (SAH) at the frequencies 45-60Hz by using lamp array as solar radiation simulator. The effectively heat transfer coefficient (HTC) of the traditional method such as strip rib on the solar collector and enhancement by piezoelectric fan are compared in detail with different mass flow rate of the air. A prototype solar collector with dimension of 300(L)×150(W)mm is fixed in a wind tunnel in the experiment. Three configurations of piezoelectric fan array have been tested, the results show that the piezoelectric fan can increase the HTC effectively, the HTC is increased 3-3.5 times compared with smooth plate and the additional power consumption of the piezoelectric fan as low as 0.6W for 2×2 piezoelectric fan array, whereas for the pressure drop of the SAH increased no more than 5%. The resonance frequencies of the two types of piezoelectric fans in experiment are 55Hz and 53Hz respectively, the maximum amplitude and the HTC achieved at the resonance frequency. It’s an effective way for SAH application compares to other methods of heat transfer enhancement in SAH and rarely be reported in the area of SAH.
Thermo-economic analysis of integrated linear Fresnel reflector gas turbine trigeneration power plants
Authors: Dabwan Yousef N. , Gang Pei
Published: August 2019

The present work provides an economic feasibility and annual performance of integrated linear Fresnel reflector gas turbine trigeneration power plant (LFR-GTPP) that is progressively being installed to produce electricity, steam and chilled water. In order to pinpoint the best integration mode, different sizes of gas turbine and solar collector’s area have been examined and presented. Thermoflow software was used for evaluating the performance of each integrated design under consideration. The optimal solar integration sizes have been determined. Moreover, reduction in CO2 emissions due to integrating the LFR system is estimated with respect to that of the conventional trigeneration plant. For the considered trigeneration plant (that is required to produce 120.5 MW of steam, and 2500kg/s of chilled water), the study revealed that LFR-GTPP with gas turbine sizes less than 190 MWe capacities have more economic feasibility and sufficient ability for utilizing solar energy. The levelized electricity cost (LEC) for the (LFR-GTPP) varied between 4.28 USȼ and 5.6 USȼ/kWh. Furthermore, the study revealed that integrating LFR system with a conventional gas turbine trigeneration power plant in Sun Belt regions leads to a considerable avoidance in CO2 emissions compared to the conventional trigeneration plant.
Design of a seasonal storage for a solar district heating in Florence
Authors: Salvestroni M , Pierucci G , Fagioli F , Pourreza A , Messeri M , Taddei F , Hosouli S , Rashidi H , Lucia M De
Published: August 2019

The energy demand in residential sector constitutes an important fraction of the entire energy consumption (40% in EU). Solar district heating (SDH) is a key strategy to reduce use of fossil fuels in buildings. Inside the European project REPLICATE, financed by Horizon 2020 SCC1 Smart Cities and Communities, a SDH with a seasonal storage (STES) has been designed to be realized in the city of Florence. It is the first example of solar district heating with a STES in Italy. The design phase has aimed to size properly the extension of solar field and the volume of seasonal storage based on several parameters such as number of dwellings to feed, heat demand, solar resource, geology of the location and economic reasons. The paper deals with the model that has been realized through TRNSYS to describe the energy fluxes of heating plant andtheir optimization process. The computational model depicts the possible operating conditions and leads to define the control strategies of solar field and seasonal storage, integrated with commercial components that complete theplant such as gas boiler, heat pump and overall circuit. Hot water tank TES has been selected as the appropriate typology of storage for this application based on geological considerations. The thickness of insulation material and various layers have been determined. The numerical analysis fixes the volume of TES to be 3800 m3 and a solar field of about 1000 m2. The solar fraction expected by the district heating is 44%.
Research on Operation Strategy of Solar Assisted Air Source Heat Pump System
Authors: Yuhan Z , Jinshun W , Mu L , Xingxing Z , Lining Z , Weiya Z , Weijie Z , Jun W , Liang X , Weihong Z , Xinru W , Yixuan W
Published: August 2019

Solar-assisted air source heat pump (SAASHP) has greatly improved the operating efficiency of the system. However, the operational performance of the key modules in the combined system is not clear. So a solar-assisted air source heat pump radiant heating system was established and a SAASHP was monitored. The key parameters of the solar collector outlet water inlet water temperature, and water tank temperature under different combined operation modes were calculated. The solar collector heat collection efficiency, system COP, and the energy consumption ratio under the corresponding mode were given. The solar collector heat collection efficiency, system COP, and the energy consumption ratio under the corresponding mode were given. Photo thermal conversion, evaporative heat transfer, and energy conversion between the condensers. By comparing the operating characteristics of each combination mode, the characteristics of SAASHP combined operation are finally obtained.
Experimental Study on Heat Storage and Release Processes of Composite Phase Change Wall under Short Intermittent Heating Conditions
Authors: Li Yanru , Li Jin , Xu Luting , Ming Yang , Long Enshen
Published: August 2019

During intermittent heating, the short intermittent conditions are common in meeting rooms of office buildings and school classrooms. The thermal process of building envelope has coupling effects on the indoor thermal environment in the frequent start-stop of heating equipment. This paper integrated phase change materials (PCMs) with building envelope to improve its thermal performance. Measurements were carried out to study the dynamic thermal process of composite phase change wall (composite-PCW) in case 1 (heating 1h + suspension 1h) and case 2 (hating 2h + suspension 2h). Results showed that: 1) the indoor air temperature fluctuations were around 14°C and 18°C respectively for case 1 and case 2 when the indoor thermal processes reached relatively stable. 2) The heat storage of composite-PCW could maintain the inner surface temperature relatively constant, so that the inner surface temperature fluctuations were only 5°C and 6°C respectively for case 1 and case 2. 3) The heat storage utilization rates of the last cycles were 5.08% and 14.86% for case 1 and case 2. Thus, the heat transferred into the wall during the heating period was stored inside the wall to improve the indoor thermal environment by rational use to maintain the inner surface temperature during the cooling-down period.
Photocatalytic activity enhanced by photo-thermal conversion with recyclable hollow Fe3O4@TiO2 nanoparticles
Authors: Shi Lei , He Yurong
Published: August 2019

Photocatalytic nanoparticles have been applied in the utilisation of solar energy because of their excellent harvesting of solar energy for wastewater treatment and chemical synthesis. In particular, TiO2 nanoparticles exhibit unique photo-catalytic performance due to their high specific surface areas and distinctive optical properties. However, the presence of nanoparticles in solar energy systems can cause secondary pollution and severely limit large-scale application of the nanoparticles in solar technology. In the present work, recoverable hollow Fe3O4@TiO2 nanoparticles were synthesized via a modified hydrothermal method. The prepared nanoparticles exhibit superior photocatalytic activity for degrading organic pollutants (Rhodamine B), which is 33.1% higher than that of P25, and the effect of photo-thermal conversion in enhancing the photo-catalytic activity of this nanoparticles was studied, which has not been investigated in most of previous reports. This study not only reveals that photo-thermal conversion plays an important role in enhancing photocatalytic activity, but also provides an approach to significantly reduce material consumption in the design of solar devices and facilitate the efficient utilization of solar energy applications.
Performance analysis of a high concentrating photovoltaic/thermal system with a water spray cooling device
Authors: Chen Haifei , Yang Jie , Zhou Nianyong , Chen Jianfang , Zhang Yang
Published: August 2019

A high concentrating photovoltaic/thermal system based on a water spray cooling device has been investigated in this paper. The system uses point-focus Fresnel lens as a concentrator with a concentration ratio over 1000. Both of the numerical thermal and electrical models have been developed to investigate the performance of the system. Moreover, the spray cooling has been used to solve the problem of high heat flux transfer and get good temperature uniformity, which is considered as an efficient method to develop the electrical efficiency and thermal efficiency. The results show that the overall efficiency is mainly influenced by water mass flow.
Study on the comprehensive energy performance of different shading systems in China
Authors: Li X , Peng JQ , Curcija C
Published: August 2019

This study evaluates the impacts of different shading systems on the comprehensive energy performance of buildings in China. Firstly, simulation models for four shading systems were developed using THERM, WINDOW and EnergyPlus. Then, four shading systems with different qualities, setting modes and baseline window systems were defined and simulated. Two cities, Beijing and Guangzhou, were selected as representative cities for heating-dominated and cooling-dominated regions in this study. Finally, the comprehensive energy performance, including cooling electricity consumption, heating electricity consumption and lighting electricity consumption for buildings with different shading systems were analysed. The results show that in Beijing, the most suitable shading system is roller shade with D quality (the combination of performance parameters), H (half shading) setting mode and low-e glazing system, while in Guangzhou, the most suitable shading system is roller shade with A quality, F (Full shading) setting mode and low-e glazing system. Besides, buildings in Beijing with suitable shading systems can achieve at least 20% energy saving potential (including air conditioning and lighting electricity consumption) compared with buildings without shading systems and the corresponding figure for Guangzhou is 50%. The conclusions of this study provide a reference for design and selection of shading systems in different regions in China.
Influencing factor Analysis of collecting capability over a year by the panel typed solar collector for seven representative cities in Yunnan, China
Authors: yang Ming , enshen Long , kuo Xu , yanru Li , yin Zhang , zhenghao Jin
Published: August 2019

Solar energy is abundant in Yunnan province, China, and buildings in this area have a surging demand for heat supply over winter season. Targeting on seven representative cities in Yunnan, this paper analyzed the optimum tilt and azimuth angles of the panel typed solar collector within these cities over a year by applying the orthogonal method, and an improved mathematical model in calculating the collected solar radiation was also developed, and the influence of the varying tilt and azimuth angles on the solar heat collection was also analyzed. Results showed that, the collected solar radiation varied in a parabola curve and was slowly decreasing after the azimuth was reaching 0° and the dip angle was approaching the location latitude, when the azimuth angle was varying from -65° to 65° and the dip angle was increasing from 0° to 90°, respectively. And among these cities, the optimum dip angles were ranging from 29° to 33° and the optimum azimuth angles were ranging from -18° to 5°, respectively, which were within the recommended ranges of the local standard. However, the maximum decrease rates of the captured solar radiation can amount to 12.15% and 2.8%, respectively, if choosing the tilt and azimuth angles of the panel typed solar collector randomly.
Analysis on the influence of solar radiation on heating load of existing residential buildings in Western Sichuan
Authors: Huang Yi , Liu Yong
Published: August 2019

The calculation of the solar radiation heat is important to the accuracy of heating load prediction, especially in area with sufficient solar radiation, e.g. western Sichuan in China. However, only a few researches are focused on the specific effects of solar radiation heat in this area. Therefore, based on a practical residential building in Western Sichuan and the survey data, the heating load during the day and night in a heating season under different working conditions are compared in this paper. The influence of solar radiation on the heating load of residential buildings in Western Sichuan is analyzed, and the correctness of the simulation software is verified by experiments. The results show that the solar radiation will greatly increase room base temperature in the daytime. In a heating season, the heating load of the building increases by 26.12% without considering solar radiation heat. During the day (9:00 to 18:00) and night (18:00 to 9:00), the heating load increases by 35.69% and 19.80%, respectively. Besides, solar radiation mainly affects the south exterior wall in a north-south residential building. The heating load of south rooms is 27.52% less than north rooms, with 35.92% less during the day and only 22.08% less during the night.
Mechanical analysis of photovoltaic panels with various boundary condition
Authors: Li Y X , Xie L Z , Zhang T Y , Wu Y P , Sun Y Y , Ni Z C , Zhang J Q , He B
Published: August 2019

The photovoltaic (PV) panels currently existed on market are a kind of laminated plate structure, which is composed of two stiff glass skins and a soft interlayer. Some of those panels are installed on the buildings and integrated as the components of the structures, such as wall and roof. In different locations, the installations of the panels are different and the boundary conditions are not simply supported any more. The generating electricity requirement of the panels needs the mechanic behaviour of them is stable with any boundary condition. In this paper the bending behaviour of PV panels with various boundary conditions is analysed and the influence of boundary condition is studied carefully. The Kirchhoff theory which is one of the classical lamination theory (CLT) is adopted to build governing equations of photovoltaic panels under static force. A Rayleigh-Rita method is modified to solve the governing equations and calculate the static deformation and stress. Different boundary condition requires different assumptions of the deflection function and a modified general function is developed to solve that problem. A theoretical solution is derived out and used to do the numerical calculation. A bending experiment of PV panel with two opposite edges simply supported and the other two free is used to verify the correctness and accuracy of the proposed solution. Finally, the influence of different boundary condition is stated by comparing the numerical results and some guides for the PV panel installation are proposed.
Study on the hysteresis characteristic of solar thermal storage system
Authors: Mao N , Long E S , Li J , Xiao D T
Published: August 2019

The thermal storage efficiency is one of the important indicators for evaluating the operation of solar thermal storage system. Affected by the thermal inertia of the system, the analysis of the relationship between the thermal storage efficiency and solar radiation, which is inadequate at the smaller time scale. This paper measured the operation of a flat plate solar collector system, studied the hysteresis characteristics of the system’s collector efficiency changes with solar radiation, took a numerical solution method for the actual lag time of the system and finally obtained the actual influence rule of solar radiation on the collection efficiency per minute. The results show that the solar collector’s efficiency change lags behind the solar radiation by 27 min; combined the lag time, the relationship between the modified thermal storage efficiency and solar radiation also were analysed; initially the modified storage efficiency per minute increases with the solar radiation, then gradually decrease after reach a certain value, due to the overall system temperature is higher and the system temperature rise is smaller when the solar radiation is large enough; the varying curve conforms to quadratic function. It provides theoretical support and practical reference for contrasting and evaluating the thermal storage efficiency changes with solar radiation in a smaller time scale.
Skylight Sizing based on balancing Daylighting Performance and Visual Comfort in Atrium Buildings
Authors: Li Jie , Chen Xueming , Ban Qichao , Yao Jiawei
Published: August 2019

As one of the most traditional and ubiquitous elements in architecture, atrium design has remained an imperative topic. With the growing concerns of energy conversation, carbon emission, comfort, and well-being recently, atrium design optimization to match the new crises and demands becomes a big challenge. This study investigated the impact of atrium shapes and building heights to daylighting performance. It was found that round atrium performs the best, next is square, and the worst one is the rectangle. And the higher the buildings are, the worse the daylight performance is. To further guide design work, generic atrium design criteria from a view of balancing daylight performance and visual comfort was proposed. The more reliable and valid annual dynamic simulation methods and climate-based daylighting modeling metrics are adopted.
The Design of Sustainable Retrofitting Strategies and Energy-efficiency Optimization for Residential Buildings
Authors: Li Guopeng , Xu Yingqing , Fan Yue
Published: August 2019

There is a huge stock of existing residential buildings in China, with high energy consumption but low comfort, so it is of great significance to retrofit the residential buildings in order to enhance energy-efficiency of the buildings. In this paper, residential buildings, built between 1980 and 2000 in typical cities of the Northeast China, are defined as the research objects. This project tries to systematically put forward an applicable design method and an overall retrofitting plan of residential buildings. Dealing with the issues of the existing research on practical retrofitting of residential buildings in China, such as short of basic data and statistics, neglect of preliminary design planning and lack of guidance evaluation criteria, this project, based on the classification of residential building envelope system, builds a façade system information modelling database of residential buildings in typical cities of the Northeast China and abstracts a design prototype. Relying on the design prototype, Matrix method is used to organize, discover and edit the retrofit design strategies. BIM - EnergyPlus integrated technique is also introduced to evaluate and optimize the design strategies suitable for reference methods for realizing the sustainable retrofitting and energy efficiency optimization. The findings of this research will extend and improve the role and scientificity of architectural design in the retrofitting of residential buildings.