bluuebunny/crossref_metadata_2025 huggingface dataset:
DABCO-mediated [3+3] cycloaddition of azomethine imines with in situ generated nitrile oxides from hydroximoyl chlorides
Authors: Fang Qing-Yun , Jin Hai-Shan , Wang Ru-Bing , Zhao Li-Ming
Published: August 2019

A novel cross 1,3-dipolar cycloaddition between azomethine imines with in situ generated nitrile oxides has been developed.
C–H alkenylation/cyclization and sulfamidation of 2-phenylisatogens usingN-oxide as a directing group
Authors: Guo Lingmei , Tang Baolan , Nie Ruifang , Liu Yanzhao , Lv Shan , Wang Huijing , Guo Li , Hai Li , Wu Yong
Published: August 2019

Ru(ii)-Catalyzed C–H alkenylation/cyclization and Ir(iii)-catalyzed C–H sulfamidation provided indol-3-one derivatives and sulfamidated 2-phenylisatogens respectively, with good yields and excellent functional group tolerance.
Structural, charge density and bond length variations in c-Y2O3influenced by progressive cerium additions
Authors: Kalaivani S. , Ponnilavan V. , Kumar P. Nandha , Kannan S.
Published: August 2019

Cerium occupancy induces expansion of the cubic Y2O3unit cell and yields a dense microstructure alongside enhanced mechanical properties.
Cohesive properties of the crystalline phases of twenty proteinogenic α-aminoacids from first-principles calculations
Authors: Červinka Ctirad , Fulem Michal
Published: August 2019

Sublimation enthalpies and proton transfer energies are calculated with a fair accuracy from the first principles for the complete 20 proteinogenic amino acid set.
Oriented assembly of CdS nanocrystals via dynamic surface modification-tailored particle interaction
Authors: Xue Xiaogang , Chi Hualin , Zhang Xiuyun , Xu Juan , Xiong Jian , Zheng Jinsheng
Published: August 2019

Dynamic hydroxyl modification-induced oriented assembly tailors the morphologies and defects, generating yellow, orange, red and cyan emissions of CdS nanocrystals.
Steric control of dioxygen activation pathways for MnII complexes supported by pentadentate, amide-containing ligands
Authors: Parham Joshua D. , Wijeratne Gayan B. , Mayfield Jaycee R. , Jackson Timothy A.
Published: August 2019

Steric control of dioxygen activation is demonstrated through O2 titration and isotopic labeling experiments for two Mn(ii) complexes.
Pb7F12Cl2: a promising infrared nonlinear optical material with high laser damage threshold
Authors: Wu Qi , Liu Xian , Liang Fei , Xu Siran , Pi Hongbing , Han Xue , Liu Yang , Lin Zheshuai , Li Yanjun
Published: August 2019

This study reports, for the first time, the second-harmonic generation (SHG) property of Pb7F12Cl2as a promising infrared nonlinear optical (NLO) material.
Inhibiting polysulfide shuttling using dual-functional nanowire/nanotube modified layers for highly stable lithium–sulfur batteries
Authors: Wang Yizhou , Liu Wenhui , Liu Ruiqing , Pan Peifeng , Suo Liyao , Chen Jun , Feng Xiaomiao , Wang Xizhang , Ma Yanwen , Huang Wei
Published: August 2019

Dual-functional MnO2 nanowire/CNT modified layers were prepared to inhibit the polysulfide shuttle effect utilizing their strong adsorption capability and high conductivity.
Enantioselective photooxygenation of β-dicarbonyl compounds in batch and flow photomicroreactors
Authors: Tang Xiao-Fei , Zhao Jing-Nan , Wu Yu-Feng , Zheng Ze-Hao , Feng Shi-Hao , Yu Zong-Yi , Liu Guang-Zhi , Meng Qing-Wei
Published: August 2019

A series of C-2′ modified cinchonine-derived phase-transfer catalysts were synthesized and applied to the photo-organocatalytic aerobic oxidation of β-dicarbonyl compounds in batch and flow photomicroreactors.
Three-state switching in a double-pole change-over nanoswitch controlled by redox-dependent self-sorting
Authors: Gaikwad Sudhakar , Özer Merve Sinem , Pramanik Susnata , Schmittel Michael
Published: August 2019

Entangled toggling leads to a rare case of a double-pole change-over switching. Since two connections are cleaved in a correlated manner, it represents an intriguing modus operandi of molecular nanoswitching.
Triflic anhydride mediated synthesis of 3,4-dihydroquinazolines: a three-component one-pot tandem procedure
Authors: Magyar Christina L. , Wall Tyler J. , Davies Steven B. , Campbell Molly V. , Barna Haven A. , Smith Sydney R. , Savich Christopher J. , Mosey R. Adam
Published: August 2019

A triflic anhydride mediated one-pot tandem reaction involving a Pictet–Spengler-like annulation step has been developed for the synthesis of 3,4-dihydroquinazolines.
Efficient and stable CsPbI3 perovskite quantum dots enabled by in situ ytterbium doping for photovoltaic applications
Authors: Shi Junwei , Li Fangchao , Yuan Jianyu , Ling Xufeng , Zhou Sijie , Qian Yuli , Ma Wanli
Published: August 2019

Colloidal perovskite nanocrystals, or quantum dots (QDs), have quickly emerged and exhibited unique opportunities for optoelectronic applications.
A novel small molecule A2A adenosine receptor agonist, indirubin-3′-monoxime, alleviates lipid-induced inflammation and insulin resistance in 3T3-L1 adipocytes
Authors: Choudhary Saynaz A. , Bora Nikita , Banerjee Dipanjan , Arora Leena , Das Anindhya Sundar , Yadav Rakesh , Klotz Karl-Norbert , Pal Durba , Jha Anupam Nath , Dasgupta Suman
Published: August 2019

Saturated free fatty acid-induced adipocyte inflammation plays a pivotal role in implementing insulin resistance and type 2 diabetes. Recent reports suggest A2A adenosine receptor (A2AAR) could be an attractive choice to counteract adipocyte inflammation and insulin resistance. Thus, an effective A2AAR agonist devoid of any toxicity is highly appealing. Here, we report that indirubin-3′-monoxime (I3M), a derivative of the bisindole alkaloid indirubin, efficiently binds and activates A2AAR which leads to the attenuation of lipid-induced adipocyte inflammation and insulin resistance. Using a combination of in silico virtual screening of potential anti-diabetic candidates and in vitro study on insulin-resistant model of 3T3-L1 adipocytes, we determined I3M through A2AAR activation markedly prevents lipid-induced impairment of the insulin signaling pathway in adipocytes without any toxic effects. While I3M restrains lipid-induced adipocyte inflammation by inhibiting NF-κB dependent pro-inflammatory cytokines expression, it also augments cAMP-mediated CREB activation and anti-inflammatory state in adipocytes. However, these attributes were compromised when cells were pretreated with the A2AAR antagonist, SCH 58261 or siRNA mediated knockdown of A2AAR. I3M, therefore, could be a valuable option to intervene adipocyte inflammation and thus showing promise for the management of insulin resistance and type 2 diabetes.
ISAR imaging of manoeuvring target with gapped data using chirp‐GAPES
Authors: Huang Darong , Guo Xinrong , Zhang Zenghui , Yu Wenxian
Published: August 2019

In inverse synthetic aperture radar (ISAR) imaging, the synthetic aperture is gapped where the echoes during some periods are not valid caused by various reasons such as interference or jamming. Usually, the gapped‐data amplitude and phase estimation (GAPES) is implemented to estimate the amplitude and phase of a sinusoidal signal. However, for the reason of the non‐cooperative motion of manoeuvring targets, the Doppler frequencies are usually time‐varying, and hence the echoes become chirps. As a result, the GAPES technique fails because of the spreading effects due to the time‐varying frequency of each scatterer contribution. In this Letter, a novel algorithm which extended the GAPES algorithm is proposed, for the ISAR imaging of manoeuvring targets with gapped data. Finally, the measured data of Yake‐42 is utilised to verify the computational effectiveness of the presented method.
Exploring credentials of Wi‐Fi sensors as a complementary transport data: an Indian experience
Authors: Gore Ninad , Arkatkar Shriniwas , Joshi Gaurang , Bhaskar Ashish
Published: August 2019

This study investigates the performance of Wi‐Fi sensors positioned at varying lateral and vertical positions on data collection efficiency under prevailing traffic conditions in India. Investigation revealed that penetration rate (a measure of performance of sensor) is significantly influenced by height and lateral position of the sensor. Time gap (time‐headway) between successive detection for varying height and the lateral position was modelled using statistical distribution to investigate, how height and lateral positions of sensor influences its performance. It was observed that the variation in time headway causes variation in the number of detections and hence, affects the performance of the sensor. A new performance measure named time‐to‐detection was developed from the observed distribution of headways and it was observed that time‐to‐detection is significantly influenced by the sensor location. Further, in addition to lateral and vertical positions, stream speed was also observed to have a significant effect on the sensor performance. Field observed headway and headway values computed using sensor data were thereafter correlated to optimise the sensor location in terms of its vertical and lateral positions. Based on the headway distribution analysis, the study recommends installing a Wi‐Fi sensor mainly at ground level along the median to capture temporal variations in traffic parameters more effectively.
Electromagnetic scattering characteristics of foil in hypersonic plasma turbulence
Authors: Jiangting Li , Teng Gong , Lixin Guo
Published: August 2019

To investigate the electromagnetic scattering problem related to a foil in a turbulent hypersonic plasma environment, the scattering field formulas for hypersonic plasma turbulence were improved by applying the anisotropic power spectrum. Using the theory of electromagnetic scattering of a conducting object, the second moment of a conducting object's scattering field is obtained in the hypersonic plasma turbulence. Finally, the backscattering cross‐section of the foil surrounded by the hypersonic plasma turbulence was calculated. The results showed that the fractal dimension led to an increase in the complexity of the hypersonic turbulent structure, and thus had a greater influence on the electromagnetic wave scattering. The scattering cross‐section of the foil in the hypersonic turbulence decreases rapidly. Meanwhile, the anisotropic parameters in the model represent scale‐dependent stretching of the turbulent eddy. As the anisotropic parameters of the turbulence increase, there will be less scattering of the hypersonic turbulence. At this point, the total scattering cross‐section of the foil in hypersonic plasma turbulence increases gradually. By improving the aerodynamic shape of the aircraft, it can produce a large number of anisotropic turbulent eddies which can effectively improve the passive jamming capability when the foil is cast.
Fault diagnosis in grid‐connected PV NPC inverters by a model‐based and data processing combined approach
Authors: Pecina Sánchez José Aagel , Campos‐Delgado Daniel U. , Espinoza‐Trejo Diego R. , Valdez‐Fernández Andres A. , De Angelo Cristian H.
Published: August 2019

This study presents a fault detection and isolation (FDI) method for open‐circuit faults (OCFs) in the switching devices of a grid‐connected neutral‐point‐clamped (NPC) inverter for photovoltaic (PV) applications. The proposed methodology addresses the fault diagnosis problem by a combined model‐based and data processing perspective to study single and simultaneous faults in the NPC inverter. For the model‐based scheme, a bank of sliding‐mode proportional–integral observers is suggested to estimate the fault profiles under an additive model. Thus, from the estimated fault profiles, and by performing a directional residual evaluation in a fixed reference frame, single and simultaneous fault scenarios can be isolated in the NPC inverter. However, for some fault classes, there is some ambiguity by just the model‐based approach that is overcome by employing the average line currents to construct extra fault signatures. The proposed FDI scheme only requires the measurements of line currents and grid voltages in the diagnosis media and can isolate single OCFs and simultaneous OCFs in the order or lower than a fundamental period of the grid frequency. Our new FDI methodology is validated through experimental data from a practical PV system in a closed‐loop grid‐connected NPC inverter under single and simultaneous OCF conditions.
Quasi‐discrete modelling of PMSM phase currents in drives with low switching‐to‐fundamental frequency ratio
Authors: Jarzebowicz Leszek
Published: August 2019

This study proposes a new quasi‐discrete approach to modelling the permanent magnet synchronous motor (PMSM). The quasi‐discrete modelling reflects the impact of continuous rotor movement, which takes place during a control cycle, on the shape of motor current waveforms. This provides much improvement in current modelling accuracy under inverter low switching‐to‐fundamental frequency operation. The proposed approach may be used in predictive control to compute current at forthcoming instants or in classical control to improve precision of determining mean current feedback. The superior accuracy of the quasi‐discrete model is confirmed by simulation and experiment for an exemplary PMSM drive operating at inverter switching frequency of 5 kHz and fundamental frequency reaching 400 Hz.
Modified step‐down series‐capacitor buck converter with insertion of a Valley‐Fill structure
Authors: Vecchia Mauricio Dalla , Van den Broeck Giel , Ravyts Simon , Tant Jeroen , Driesen Johan
Published: August 2019

This study proposes a step‐down converter based on the non‐synchronous series‐capacitor buck converter. Instead of the regular capacitor of the series topology, the Valley‐Fill capacitor‐diode structure is inserted in order to extend the step‐down conversion ratio of the converter from D/2 to D/3, which leads to a gain ranging from 0 to 1/6, since the maximum allowed duty cycle is D = 0.5. The power stage employs only two active switches, five diodes, two capacitors and two inductors. The study investigates the mechanism of the Valley‐Fill structure, analyses the pulse width modulation stages during a switching period, theoretically derives the gain considering ideal and non‐ideal components, characterises the current distribution for the inductors and the voltage and current stresses among the power semiconductors and capacitors of the power stage. The proposed topology will be qualitatively and quantitatively compared to state‐of‐the‐art step‐down converters with similar gain. The study includes simulation and experimental results for a 300 V/12 V prototype up to 100 W of power and operating at 100 kHz switching frequency.
Optimal cascaded predictive control for photovoltaic systems: application based on predictive emulator
Authors: Remache Seif El Islam , Cherif Ali Yahia , Barra Kamel
Published: August 2019

The present study sheds new light on advanced control methods of photovoltaic (PV) emulators using finite set model predictive control (FS‐MPC). In the first part of the study, a predictive PV emulator (P‐PVE) based on a Buck converter is proposed and tested under hard climatic conditions and load variations. The high performance of the P‐PVE in terms of dynamic response, reference tracking, accuracy, simplicity, and efficiency is confirmed experimentally when compared with those of the commonly used one based PI controller. The second part of the study proposes an efficient cascaded predictive control (CPC) method applied on two topologies of PV systems, namely the stand‐alone system and the grid‐connected system. In each topology, the P‐PVE is cascaded to a maximum power point tracking Boost converter in order to track efficiently the maximum power point. In addition to the high performance offered by the FS‐MPC, the proposed control strategy allows to control all cascaded converters at the same time in one stage instead of controlling them separately, thus providing more flexibility and simple controllability. Extensive experimental results are done confirming the correctness and the effectiveness of the proposed CPC under hard climatic conditions, even in the presence of distorted grid voltage.
Evolutionary multi‐objective optimisation of the pulse burst waveform in solid‐state VHF moving target detection radar
Authors: Jevtić Miloš , Zogović Nikola , Graovac Stevica
Published: August 2019

A solid‐state, very high frequency (VHF) band, moving target detection air surveillance radar requires a complex pulse burst waveform to mitigate the visibility issues originating from the blind Doppler intervals and range eclipsing. The waveform employs multiple pulse repetition frequencies to mitigate the effects of the blind Doppler intervals and interleaves short and long pulses to mitigate range eclipsing. In the authors’ previous works, they pointed out that the waveform design is a multi‐objective optimisation problem and defined the mathematical model of the waveform optimisation problem. They also presented how the exact Pareto optimal (PO) set can be determined by means of exhaustive search. In this paper, they improve the mathematical model of the waveform optimisation problem by altering the way in which one of the objective functions is calculated and adding a new constraint, which eliminates meaningless solutions. Finally, they propose a solution method based on a multi‐objective evolutionary algorithm. The performance evaluation test indicates that compared to the exhaustive search, the proposed method provides a solution that is insignificantly different. However, the proposed method is more scalable and requires over three orders of magnitude smaller number of comparisons to determine the PO set, which makes it more viable for the online waveform adaptation.
Collaborative forward‐looking imaging and reconnaissance technology for manned/unmanned aerial vehicles
Authors: Meng Ziqiang , Li Xiaoming , Lu Chengjun , Zhu Daiyin
Published: August 2019

With the imaging advantage of bistatic forward‐looking synthetic aperture radar, collaborative forward‐looking imaging and reconnaissance technology for manned/unmanned aerial vehicles could be performed, in which unmanned aerial vehicle can realise two‐dimensional (2‐D) and high‐resolution imaging and further attacking targets in its straight‐ahead position. However, there exists more complicated space‐variance property in this special configuration than traditional mono‐static SAR. Such property will lead to performance deterioration of imaging if not corrected effectively. To address this problem, 2‐D frequency spectrum with high precision is first obtained based on squint minimisation method here, and then a novel‐phase space‐variance correction method is developed through polynomial fitting. Imaging focus performance on targets could be improved significantly with authors’ method. Several simulations for scattering targets confirm its validity.
High‐resolution distributed ISAR imaging by OMP method
Authors: Li Yuanyuan , Fu Yaowen , Zhang Wenpeng
Published: August 2019

The distributed inverse synthetic aperture radar (ISAR) technique can form multiple virtual sensors and has the potential to increase the cross‐range resolution by exploiting the multi‐channel echoes. In the existing imaging approaches, the echoes acquired from different virtual sensors are rearranged into an equivalent single‐channel ISAR signal firstly. Then, the missing data between the observation angles of any two adjacent sensors is restored by interpolation. Thus, the echo with long observation time can be acquired. After the fast Fourier transform on this echo, the improved cross‐range resolution image can be acquired. However, when the gaps are large, the recovered missing data is very inaccurate. Secondly, if the target rotates non‐uniformly and the change of the observation angle is not a linear function with the slow time, the equivalent single‐channel ISAR echo cannot be obtained by interpolation. Therefore, this study aims to avoid these drawbacks and get desired distributed ISAR imaging results. After sparse representation of the distributed ISAR echoes, the orthogonal matching pursuit algorithm is used to position the scatterers in every range bin and the final high‐resolution ISAR image can be obtained. Simulations show the effectiveness of the proposed method to deal with aforementioned problems.
The VIMOS Public Extragalactic Redshift Survey (VIPERS)
Authors: Gargiulo A. , Cucciati O. , Garilli B. , Scodeggio M. , Bolzonella M. , Zamorani G. , De Lucia G. , Krywult J. , Guzzo L. , Granett B. R. , de la Torre S. , Abbas U. , Adami C. , Arnouts S. , Bottini D. , Cappi A. , Franzetti P. , Fritz A. , Haines C. , Hawken A. J. , Iovino A. , Le Brun V. , Le Fèvre O. , Maccagni D. , Małek K. , Marulli F. , Moutard T. , Polletta M. , Pollo A. , Tasca L. A. M. , Tojeiro R. , Vergani D. , Zanichelli A. , Bel J. , Branchini E. , Coupon J. , Ilbert O. , Moscardini L. , Peacock J. A.
Published: August 2019

We use the unparalleled statistics of the VIPERS survey to investigate the relation between the surface mean stellar mass density Σ = ℳ/(2 πRe2) of massive passive galaxies (MPGs, ℳ ≥ 1011 M⊙) and their local environment in the redshift range 0.5 ≤ z ≤ 0.8. Passive galaxies were selected on the basis of their NUVrK colors (∼900 objects), and the environment was defined as the galaxy density contrast, δ, using the fifth nearest-neighbor approach. The analysis of Σ versus δ was carried out in two stellar mass bins. In galaxies with ℳ ≤ 2 × 1011 M⊙, no correlation between Σ and δ is observed. This implies that the accretion of satellite galaxies, which is more frequent in denser environments (groups or cluster outskirts) and efficient in reducing the galaxy Σ, is not relevant in the formation and evolution of these systems. Conversely, in galaxies with ℳ > 2 × 1011 M⊙, we find an excess of MPGs with low Σ and a deficit of high-Σ MPGs in the densest regions with respect to other environments. We interpret this result as due to the migration of some high-Σ MPGs (< 1% of the total population of MPGs) into low-Σ MPGs, probably through mergers or cannibalism of small satellites. In summary, our results imply that the accretion of satellite galaxies has a marginal role in the mass-assembly history of most MPGs. We have previously found that the number density of VIPERS massive star-forming galaxies (MSFGs) declines rapidily from z = 0.8 to z = 0.5, which mirrors the rapid increase in the number density of MPGs. This indicates that the MSFGs at z ≥ 0.8 migrate to the MPG population. Here, we investigate the Σ–δ relation of MSFGs at z ≥ 0.8 and find that it is consistent within 1σ with that of low-Σ MPGs at z ≤ 0.8. Thus, the results of this and our previous paper show that MSFGs at z ≥ 0.8 are consistent in terms of number and environment with being the progenitors of low-Σ MPGs at z <  0.8.
Experimental Evaluation of the Ability of an Auxiliary Heating Device to Reduce the Condensation Risk around Built-in Wardrobes of Apartment Buildings in Winter
Authors: Lee Chae Lyn , Lee Hyun Hwa , Lim Jae Han , Song Seung Yeong
Published: August 2019

Recently, there has been an increase in the condensation and mould problems of apartment buildings in Korea owing to the high insulation and high air-tightness performance of buildings, which increase energy savings. Condensation is generally found in winter on furniture back panels and adjacent surfaces of the wall, floor, and ceiling. These problems are related to the weather conditions and indoor room conditions in winter. To solve these problems, an auxiliary heating device that can be installed was developed. The purpose of this study was to evaluate condensation risk in the condensation vulnerable areas around built-in furniture of apartment buildings by installing an auxiliary heating device. The experimental results reveal that condensation risk can be reduced by comparing the thermal environment around the built-in furniture with and without installation of an auxiliary heating device in winter. Furthermore, they reveal that it is possible to increase the surface temperature of vulnerable areas around built-in wardrobe by applying an auxiliary heating device to minimize condensation problems by using a minimum device.
Thermal Comfort Analysis in Naturally-Ventilated Handball Arena Utilizing CFD Techniques
Authors: Masoud Ahmed A. , Khalil Essam E. , Ibrahim Abdelmaged H. , ElBialy Esmail M.
Published: August 2019

This work investigates the feasibility and thermal comfort of using natural ventilation in order to achieve thermal comfort in a handball arena with realistic dimensions and a full occupation of 4300 persons in the Gulf area. The work numerically simulates the temperature and velocity fields inside the full arena using computational fluid dynamics techniques at different internal loads, prevailing wind speeds, prevailing wind temperatures and prevailing wind angles. The work generates certain air opening configuration to be used for natural ventilation and the results show that natural ventilation is feasible if the following conditions are met simultaneously: the occupation density is 25% or less, sitting in the prevailing wind side, the lighting load does not exceed 50% of its full capacity, the prevailing wind temperature does not exceed 30 °C and the prevailing wind velocity is in range 3-4 m/s, where the upper limit arises from the requirement to avoid high velocities in the playing area. These conditions can be met during the training time and during parts of the day and over parts of the year hours making this method conditionally feasible.
Review on the Surface Heat Transfer Coefficients of Radiant Systems
Authors: Shinoda Jun , Kazanci Ongun B. , Tanabe Shin-ichi , Olesen Bjarne W.
Published: August 2019

Heat transfer coefficients are often used to describe the thermal behaviour of radiant systems and how it transfers heat between the cooled/heated surface and the room. In addition to current standards, numerous studies have been conducted to obtain the heat transfer coefficients through experiments and simulations. However, inconsistency is evident in the values or expressions suggested. Thus, this study investigated possible sources of discrepancy through an extensive literature review on articles and standards that focused on the heat transfer coefficients at the cooled/heated surface. Measurement data provided by different authors were extracted to compare both the amount of heat transfer and the actual heat transfer coefficients. Consequently, suggested values and expressions were used to predict the measurement data in other articles to examine their accuracy. Comparison of the results showed that the radiant heat transfer coefficients had a consistent value throughout the literature and had prediction error within ±20%. However, larger deviations and prediction errors were seen in the total and convective heat transfer. It was suggested that some of the sources of error may have been the calculation procedure of each heat transfer mechanism, choice of reference temperature and its measurement height/position, and room dimensions.
Analysis of Backward and Forward Effects on a Grooved Co-axial Heat Exchanger by Response Surface Methodology
Authors: GÜNGÖR Şahin , AYDIN Levent , CEYHAN Umut , KAYA Büşra , KARADENİZ Ziya Haktan
Published: August 2019

In the literature, it is proved that grooved pipe models are thermally more efficient than the smooth pipe model. Different than the previous studies in which the groove dimensions are constant along the pipe, we study the effect of groove radius and the gap between adjacent grooves on the local heat transfer coefficients using computational fluid dynamics software. The grooved section consists of three sub-sections to see the effects of groove dimension in stream-wise flow direction. We vary the radius of circular grooves parametrically in each section to optimize the local groove radius throughout the pipe. We couple the fluid flow (1200<Re<24000) with energy equations, and the grooved sections are set as heated wall at constant temperature of 350 K. The optimal mesh has been selected by performing mesh independence study and finer mesh has been used in heated wall section. The radii of grooves are varied from 2 to 6 mm with an increment of 0.2 mm considering the manufacturability of the pipe, to do so we use the design of experiments (DOE). All DOE tools in ANSYS software are examined and compared with full factorial results. After DOE process, local heat transfer coefficient values of all groove parts are examined by response surface methodology (RSM).
Effects on the Ventilation of a Two-Storey Building under Different Thermal Conditions
Authors: Röder Tim , Mathis Paul , Müller Dirk
Published: August 2019

In this paper it is shown how the air flow rate of decentralized ventilation devices can be affected by a staircase of a two-storey building under different thermal conditions. Since these devices need local fans for supplying the requested volume flow, pressure loads have a significant impact on the delivered volume flow rates. Regarding this, the study comprises two analyses: First, a CFD-model is developed to simulate the ventilation air flow through a simplified staircase. By varying parameters for rooms’ temperature and ventilation direction, the hydrostatic pressure in the staircase is evaluated. The simulations – characterized by high Archimedes numbers – are successfully validated with findings from preliminary work. In a second part, the pressure conditions inside the staircase are referred to outside conditions. Consequently, a static pressure difference at the ventilation device on each storey can be observed.

We found that the deliverable volume air flow rate can decrease up to 10 % from the nominal flow rate due to temperature differences between the storeys and outside. Therefore, heat recovery and ventilation effectiveness may also be impaired.
Design of a dew point evaporative cooler for buildings in Mediterranean climate
Authors: Abada Djallel , Maalouf Chadi , MOUSSA Tala , Boudjabi Amel Ferial , Polidori Guillaume , Rouag-Saffidine Djamila , Sotehi Oualid , Derghout Zoheir , Wurtz Etienne
Published: August 2019

Refreshing air remains a crucial problem in warm climates where electricity consumption for air conditioning has become excessive and irrational for several years, notably in Algeria. Research in this field is increasingly oriented towards new techniques that can reduce costs and environmental impacts. Among these techniques, the evaporative dew point cooling technology is the most promising as it can cool outdoor air to temperatures below its wet bulb temperature. The aim of this work is to model and design a dew point cooler for french and algerian climates. This model is used to study the effect of the cooler parameters such as its length, water temperature and working air ratio on its cooling effectiveness and supply temperature.
Odor Problems in Toilets with Reduced Ventilation Frequencies
Authors: Kimura Madoka , Akimoto Takashi , Hirasuga Nobuhiro , Sakamoto Yu , Yamakita Sakurako , Sakakibara Hikari
Published: August 2019

Japan’s toilets are generally ventilated 15 times per hour. Despite the development in toilets, the ventilation frequency in toilets has not been changed in recent times. Therefore, there is a possibility that toilets are being excessively ventilated. Reducing the ventilation frequency increases the return air to the heat exchanger and improves the efficiency of the heat exchanger. For an optimal ventilation frequency, we introduce a system that could control the exhaust air using sensors. The primary issue is the odor caused by reducing the ventilation frequency. In this study, we aim to eliminate the odor as quickly as possible by providing an exhaust port at the bottom of the wall (hereinafter referred as “baseboard deodorization”). First, we examined the relationship among the odor sensor, human’s olfactory odor identification and ventilation volumes with the toilet in operation to verify the usefulness of the sensors. Next, the air environment was analyzed using computational fluid dynamics (CFD). The results of the measurements and questionnaire survey indicate a correlation between the degree of contamination in the air and the odor intensity. The CFD analyses demonstrated, even after the frequency of ventilation reduced to 5 times per hour, that the ammonia concentration obtained was equivalent to 15 times per hour. To solve the odor problem due to the ventilation reduction, it is important to evacuate air immediately after the odor is generated. Among others, it was observed that a baseboard deodorization system contributes significantly to the reduction in ammonia concentration.
Comfort and satisfaction of patients, visitors and staff with patient rooms at inpatient wards, a pilot study
Authors: Eijkelenboom AnneMarie , Blok Geke A. , Bluyssen Philomena M.
Published: August 2019

The indoor environmental quality, control, layout and appearance may affect comfort and satisfaction of patients, as well as visitors and staff in hospitals. Due to differences in activities, duration of stay and health status, needs of the different groups may vary. In order to design hospitals, which positively support comfort and satisfaction of all occupants, information is needed about satisfaction and the perceived importance of different factors. This study compared comfort and satisfaction of patients, visitors and staff with inpatient bedrooms (single and multiple bedrooms). A questionnaire was designed with rating scale questions; 499 respondents participated. The groups varied in their satisfaction. Staff was the least satisfied group. All groups were most satisfied with the appearance of the patient room and least satisfied with control. A qualitative study on control may strengthen the validity of the questionnaire for future research. In order to gain more insight in the importance of different aspects, an extension of the questionnaire, regarding questions about health.
The CO2 conditions within the baby cots of day care centres
Authors: Braun Gert-Jan , Zeiler Wim
Published: August 2019

The indoor quality of an occupied space is very important for the well-being of its occupants, especially in the case of young children. Although nowadays little children spend a lot of their time in day care centres, relatively little is known about the effects of different indoor environmental factors present in these day care centres. Therefore this research investigated the indoor air quality of the sleeping accommodation of two Dutch day care centre as well as the conditions with the baby cots. Besides an extensive literature research actual measurements were performed in two day care cent to find out the indoor air conditions within baby cots. The results of the detailed studies were compared with the results of earlier Dutch studies in day care centres. Although, our latest findings were not as bad as results from our earlier case studies, still more attention is needed to get a better understanding of the current situation in which babies sleep.
Effects of Wellness Conscious Buildings on the Well-being and Comfort of Workers
Authors: Nakamura Sosui , Tanabe Shin-ichi , Fujisawa Junta , Takai Emi , Tsushima Sayana , Ogata Masayuki , Tsuneoka Yugo , Iida Takayoshi , Uno Yoshitaka , Nomura Ryoko , Ukiana Tomo-oki
Published: August 2019

In recent years, Mental and physical health of office workers is regarded as a problem and the office buildings which improve workers’ wellness. The WELL Building Standard was announced with the aim of improving the health condition of building users in 2014. The purpose of this study is to demonstrate the improvement of the health condition of the office workers who work at the office applying WELL Building Standard. To achieve this purpose, low-score office and high-score office for WELL Building Standard scores were created by changing the indoor environment and furniture in the office, and subject experiments in which we perform the work were conducted in each condition. From the experimental results, we propose environmental control and introduction furniture to verify changes in health condition of office workers, to improve the wellness of building users, and to bring synergy effects to health. It was confirmed that working at plural spaces which workers chose themselves.
The effect of the contaminant emission rate on the velocity field and contaminant distribution with the presence of an obstacle in a large space
Authors: Zhang Qianru , Zhi Chengqiang , Huang Yixiang , Ye Wei , Gao Jun , Zhang Xu
Published: August 2019

In the industrial field, the prediction of the contaminant gas distribution is very meaningful. However, when the leakage is high, not only the contaminant distribution will not follow the pattern of the original flowfield, but the contaminant buoyancy or negative buoyancy will affect the flowfield conversely. In this study, we focus on the effect of the contaminant emission rate on the velocity field and contaminant distribution with an obstacle in a large space by means of CFD simulation. Two leaking positions and five emission rates of the source have been taken into consideration. When the emission rate is high enough, the flowfield structure will be altered and new vortexes will appear. The contaminant dimensionless concentration distribution is totally different from the low-emission-rate conditions. The flammable region becomes significant, which leads to the potential risk of explosion.
The notion of comfort, from word to concept
Authors: Dună Ştefan , Silviu Doboşi Ioan , Mihăilă Dragoș , Teodorescu Daniel , Troi Laura
Published: August 2019

The notion of comfort emerged from a background of constraints caused by environmental, social, psychological, technological etc. factors, as a human attitude and endeavor to diminish these constraints and then to improve other elements that could ensure a different quality standard of life. In the last two decades, one can perceive an intensification of the efforts put into revealing the factors, together with their limitations, which contribute to achieving the state of comfort in various types of buildings considered isolated or in relation to others, in a rural or urban setting, and putting them into a standardized format that is to be taken into account. The increasing debates between specialists on the one hand and between specialists and occupants/users/residents on the other hand regarding the addition of new factors or the preeminence of their importance generates the re-contextualization of the notion of “comfort”, whose elements are presented in this study. The last chapter proposes a different approach and understanding of the notion of comfort which can thus become a concept that finds its starting point in the way man is structured as a living being and takes
Archetype definition for analysing retrofit solutions in urban areas in Europe
Authors: De Carli Michele , Carnieletto Laura , Di Bella Antonino , Graci Samantha , Emmi Giuseppe , Zarrella Angelo , Baseggio Nicola , Belliardi Marco , Rossi Leonardo , Mulè Stagno Luciano , Badenes Borja , Urchueguía Javier , Sanner Burkhard , Cadelano Gianluca , Bernardi Adriana
Published: August 2019

Ground Source Heat Pumps (GSHP) are gaining interest for many applications and a very difficult task is to look at their affordability in urban environments with limited spaces. For this reason, the EU project GEO4CIVHIC has been funded. In order to set up different cases with different levels of retrofit and try to generalize results, the project focuses the activity on archetypes, i.e. buildings which may represent the usual type of building which may be found more frequently in urban environments around Europe. The analysis of the archetypes has been based on literature review and analysing the existing databases of buildings in Europe. The work allowed to determine a reference building for single family house and a building representing an apartment block for multi-users. In this latest case two types of possible uses have been examined: residential building and office building. In order to set up different levels of retrofit and cost-effective solutions, three different climates have been defined: warm climate, mild climate and cold climate. The climatic conditions do not only affect the energy demand of the building and the peak power needed for heating and cooling, but also determine different ways of buildings’ construction and define different levels of insulation. Last but not least, the buildings have been also subdivided into existing buildings, i.e. built up from 1960 to 2000 and historic buildings, i.e. buildings earlier than 1960. The paper presents the first step of the research which permitted to define the different archetypes, their dimensions and way they are constructed. Moreover, the different simulations allowed to define the energy needs of the buildings as well as the peak power for heating and cooling. This allows to create a matrix for the different levels of retrofit solutions which will be associated to related costs for a cost-benefit analysis to check the most achievable solutions.
Thermal Zones Modelling for an Energy Efficient Commercial Building – Case Study
Authors: Tamaş (Papuc) Elena Camelia , Hera Dragoş , Flamaropol Gianni , Ţârlea Graţiela Maria
Published: August 2019

Our paper is referring to a commercial building having a good thermal insulation, compacted shape with three basements, from which two are for parking and technical areas in the underground, and the other floors are mainly for retail, technical rooms, offices and a terrace for walking and events. The methodology used in our building thermal zones modelling analysis is including: all used measured areas within the building; all materials related to the building envelope with high thermal efficiency values; all activities performed within the respective areas; the heating and cooling activities for each zone; the lighting and controls used for each zone; the building geometry related to the data requirements, loads, air conditioning and lighting systems areas; the building usage schedules; Heating Ventilation and Air Conditioning (HVAC) and electrical system specifications along the weather data. The building thermal zones modelling simulation was performed based on the air set point temperature, ventilation fresh air rate and the room destination. After monitoring the building along four operational years, the energy consumptions for heating and cooling systems were obtained for each thermal zone and for the entire building. Some technical measures to improve the building energy performances are proposed based on the monitoring period.
Cost-efficient Nearly Zero-Energy Buildings
Authors: Erhorn-Kluttig Heike , Erhorn Hans , Illner Micha
Published: August 2019

The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and also even higher energy performance levels throughout all EU countries. However, most of the high performance buildings realised so far result in higher investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU H2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The focus is on multi-family houses. In each of the four participating countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of marketready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies.
Quicker Measurement of Walls’ Thermal Resistance Following an Extension to ISO 9869 Average Method
Authors: Rasooli Arash , Itard Laure
Published: August 2019

Determination of the thermo-physical characteristics of the buildings’ components is crucial to illustrate their thermal behavior and therefore their energy consumption. Along the same line, accurate determination of the thermal resistance of the building walls falls into one the most important targets. Following the difference between in-lab, and on site thermal performance of walls, in-situ measurements have been highly recommended. The most well-known practice for in-situ measurement of walls’ thermal resistance is the Average Method of ISO 9869, using one heat flux meter and two thermocouples. The method, in comparison with other existing methods is quite straight-forward and therefore, is applied widely in large scale. Despite its simplicity, this method usually needs a relatively long time to reach an acceptable result. The current paper deals with a modification to the ISO 9869 method, making it in many situations much quicker than its original state. Through simulation of walls of different typologies, it is shown in which cases the measurement period becomes longer than expected. It is demonstrated how the addition of a heat flux meter to the aforementioned equipment can lead to a much quicker achievement of the thermal resistance, following the rest of the instructions of the standard method.
Potential of spatial use patterns for developing localized conditioning systems to reduce energy consumption
Authors: Van Loy Nick , Verbeeck Griet , Knapen Elke
Published: August 2019

In this paper, the spatial use of three underused semi-detached dwellings in Belgium is discussed. The exact user patterns of residents within rooms have been monitored during one week. In the analysis, a distinction has been made between spaces where people move through and have a higher metabolic rate and places where residents stay or sit for a longer time. The analysis shows that residents use some of the rooms only partially and others only for circulation. Furthermore, residents stay only at particular places in the room for a longer period of time. These zones or places are linked to the common activities. Nowadays, most dwellings are heated by a single-zone heating system that heats multiple rooms completely at the same time. However, the spatial use of residents not only shows that particular places in a room are used, but also that they are used at different times. This research illustrates the potential of spatial use patterns for the development of heating systems that are better adapted to the effective spatial use, the activity patterns and corresponding required temperature in residential buildings. This could result in a lower overall ambient temperature and an improved energy efficiency of the building.
Experimental performance analysis of a multiple-source and multiple-use heat pump system: a predictive ANN model of sky-source heat pump
Authors: Wen Ke , Ooka Ryozo , Hino Toshiyuki , Liu Mingzhe , Lee Doyun , Choi Wonjun , Ikeda Shintaro , Palasz Djafar Reza
Published: August 2019

In this study, an artificial neural network (ANN) was used to model the thermal performance of a novel direct-expansion solar-assisted sky-source heat pump (SSHP) during winter. The input parameters of the ANN take into account the weather conditions, water loop characteristics, and the compressor characteristics of the SSHP. The following four output parameters were adopted to evaluate the SSHP performance: the outlet water temperature of the water loop, electricity consumption, heat production, and the coefficient of performance. To increase the accuracy of the ANN and simultaneously investigate the effects of each of the input parameters on the performance of the SSHP, the combination of input parameters for the validation data set was varied in multiple case studies. Additionally, learning curves were introduced to clarify the relationship between the training data size and the generalization performance of the ANN. Finally, the ANNs with the best performance were selected and evaluated based on the test data set by using metrics such as the root mean square error. The reported results demonstrated that the ANN model has comparatively high SSHP winter performance prediction accuracy.