bluuebunny/crossref_metadata_2025 huggingface dataset:
Element Segregation and Electrical Properties of PMN-32PT Grown Using the Bridgman Method
Authors: Wang Sijia , Xi Zengzhe , Fang Pinyang , Li Xiaojuan , Long Wei , He Aiguo
Published: February 2019

A single crystal with nominal composition Pb(Mg1/3Nb2/3)O3-32PbTiO3 (PMN-32PT) was grown by the Bridgman technique. Crystal orientation was determined using the rotating orientation X-ray diffraction (RO-XRD). Element distribution was measured along different directions using inductively coupled plasma-mass spectrometry (ICP-MS). The effect of the element segregation along axial and radial directions on the electrical properties of the PMN-32PT crystal was investigated. It is indicated that the electrical properties of the samples along the axial direction were strongly dependent on the PT (PbTiO3) content. With the increase of the PT content, the piezoelectric coefficient and remnant polarization were improved. Differently, the electrical properties of the samples along the radial direction were mainly determined by the ratio of the Nb and Mg. The reasons for the element segregation and electrical properties varied with the composition were discussed.
Influence of Selected Saccharides on the Precipitation of Calcium-Vaterite Mixtures by the CO2 Bubbling Method
Authors: Konopacka-Łyskawa Donata , Czaplicka Natalia , Kościelska Barbara , Łapiński Marcin , Gębicki Jacek
Published: February 2019

Calcium carbonate is a compound existing in living organisms and produced for many biomedical applications. In this work, calcium carbonate was synthesized by a CO2 bubbling method using ammonia as a CO2 absorption promotor. Glucose, fructose, sucrose, and trehalose were added into the reaction mixture to modify characteristics of precipitated calcium carbonate particles. To determine the polymorphic form of produced calcium carbonate particles, Fourier transform infrared spectroscopy (FTIR-ATR) and X-ray diffraction (XRD) analysis were performed. Scanning electron microscopy (SEM) was used to estimate the size and shape of produced particles. Mixtures of vaterite and calcite were synthesized in all experiments. The percentage content of the vaterite in the samples depended on used additive. The highest concentration of vaterite (90%) was produced from a solution containing sucrose, while the lowest concentration (2%) was when fructose was added. Saccharides affected the rate of CO2 absorption, which resulted in a change in the precipitation rate and, therefore, the polymorphic composition of calcium carbonate obtained in the presence of saccharides was more varied.
Hierarchical Core/Shell Structured Ag@Ni(OH)2 Nanospheres as Binder-Free Electrodes for High Performance Supercapacitors
Authors: Lv Sa , Chu Xuefeng , Yang Fan , Wang Huan , Yang Jia , Chi Yaodan , Yang Xiaotian
Published: February 2019

Hierarchical Ag@Ni(OH)2 nanospheres were achieved directly on copper foam substrate through a convenient two-step process. Ag nanoflowers were formed on copper substrate by galvanic replacement technology between AgNO3 and copper foam followed by electrodeposition of a layer of Ni(OH)2. Ag nanostructures as cores not only dominated the final morphology of the composites, but also improved the electrical conductivity, increased the specific surface area of the active electrode material, and even directly participated in the electrochemical reactions. The resulted Ag@Ni(OH)2 nanospheres could be directly used as high-performance binder-free electrodes and exhibited enhanced electrochemical performance with a high specific capacitance of 1.864 F cm−2 and long cycling lifespans of 90.43% capacity retaining after 3000 cycles.
Mitochondrial Genomes from New Zealand’s Extinct Adzebills (Aves: Aptornithidae: Aptornis) Support a Sister-Taxon Relationship with the Afro-Madagascan Sarothruridae
Authors: Boast Alexander P. , Chapman Brendan , Herrera Michael B. , Worthy Trevor H. , Scofield R. Paul , Tennyson Alan J. D. , Houde Peter , Bunce Michael , Cooper Alan , Mitchell Kieren J.
Published: February 2019

The recently extinct New Zealand adzebills (Aptornithidae, Aptornis spp.) were an enigmatic group of large flightless birds that have long eluded precise taxonomic assignment as they do not closely resemble any extant birds. Adzebills were nearly wingless, weighed approximately 16–19 kg, and possessed massive adze-like reinforced bills whose function remains unknown. Using hybridisation enrichment and high-throughput sequencing of DNA extracted from subfossil bone and eggshell, near-complete mitochondrial genomes were successfully assembled from the two Quaternary adzebill species: the North Island Adzebill (Aptornis otidiformis) and South Island Adzebill (A. defossor). Molecular phylogenetic analyses confirm that adzebills are members of the Ralloidea (rails and allies) and are sister-taxon to the Sarothruridae, which our results suggest comprises the Madagascan wood rails (Mentocrex, two likely sp.) in addition to the tiny (<50 gram) rail-like Afro-Madagascan flufftails (Sarothrura, 9 spp.). Node age estimates indicate that the split between adzebills and Sarothruridae occurred ~39.6 Ma, suggesting that the ancestors of the adzebills arrived in New Zealand by long-distance dispersal rather than continental vicariance. This newly identified biogeographic link between physically distant New Zealand and Afro-Madagascar, echoed by the relationship between the New Zealand kiwi (Apterygiformes) and Madagascan elephant-birds (Aepyornithiformes), suggests that the adzebill’s near relatives were formerly more widespread. In addition, our estimate for the divergence time between the two Quaternary adzebill species (0.2–2.3 Ma) coincides with the emergence of a land-bridge between the North and South islands of New Zealand (ca. 1.5–2 Ma). This relatively recent divergence suggests that North Island adzebills are the result of a relatively recent dispersal from the South Island, from which the earliest (Miocene) adzebill fossil has been described.
Macroscopic Cluster Organizations Change the Complexity of Neural Activity
Authors: Park Jihoon , Ichinose Koki , Kawai Yuji , Suzuki Junichi , Asada Minoru , Mori Hiroki
Published: February 2019

In this study, simulations are conducted using a network model to examine how the macroscopic network in the brain is related to the complexity of activity for each region. The network model is composed of multiple neuron groups, each of which consists of spiking neurons with different topological properties of a macroscopic network based on the Watts and Strogatz model. The complexity of spontaneous activity is analyzed using multiscale entropy, and the structural properties of the network are analyzed using complex network theory. Experimental results show that a macroscopic structure with high clustering and high degree centrality increases the firing rates of neurons in a neuron group and enhances intraconnections from the excitatory neurons to inhibitory neurons in a neuron group. As a result, the intensity of the specific frequency components of neural activity increases. This decreases the complexity of neural activity. Finally, we discuss the research relevance of the complexity of the brain activity.
Secrecy Performance Enhancement for Underlay Cognitive Radio Networks Employing Cooperative Multi-Hop Transmission with and without Presence of Hardware Impairments
Authors: Tran Tin Phu , The Hung Dang , Nguyen Tan N. , Duy Tran Trung , Voznak Miroslav
Published: February 2019

In this paper, we consider a cooperative multi-hop secured transmission protocol to underlay cognitive radio networks. In the proposed protocol, a secondary source attempts to transmit its data to a secondary destination with the assistance of multiple secondary relays. In addition, there exists a secondary eavesdropper who tries to overhear the source data. Under a maximum interference level required by a primary user, the secondary source and relay nodes must adjust their transmit power. We first formulate effective signal-to-interference-plus-noise ratio (SINR) as well as secrecy capacity under the constraints of the maximum transmit power, the interference threshold and the hardware impairment level. Furthermore, when the hardware impairment level is relaxed, we derive exact and asymptotic expressions of end-to-end secrecy outage probability over Rayleigh fading channels by using the recursive method. The derived expressions were verified by simulations, in which the proposed scheme outperformed the conventional multi-hop direct transmission protocol.
Exploring Turkish Pre-Service Teachers’ Perceptions and Views of Digital Literacy
Authors: Ata Rıdvan , Yıldırım Kasım
Published: February 2019

This study aims to investigate digital literacy perceptions of preservice teachers, and to identify quantity characteristics of first and second year preservice teachers’ digital literacy at a public university in Turkey. That is, pre-service teachers’ perceptions of digital literacy and their patterns of knowledge and use of digital literacy were measured within the scope of this study. Multiple sources of data, including a Likert scale and open-ended questions were collected to address the topic. Various statistical techniques and tests such as ANOVA, t-test, and Tukey HSD test were used in the analysis of the obtained data. Qualitative data was analyzed by using the content analysis method. The findings indicated that the model showed a good fit with the data and standardized regression weights indicated that attitude, technical, cognitive, and social factors were significant predictors of digital literacy. In addition, it was identified that the pre-service teachers had high and positive perceptions of digital literacy. However, it was observed in the open-ended questions that they lack the refined cognitive skills to find, evaluate, create, and communicate. The findings were then discussed in light of the relevant literature.
A Nonisolated Three-Port DC–DC Converter with Continuous Input and Output Currents Based on Cuk Topology for PV/Fuel Cell Applications
Authors: Chandrasekar Balaji , Nallaperumal Chellammal , Dash Subranshu Sekhar
Published: February 2019

A nonisolated three-port DC–DC converter based on Cuk topology (NI-TPC) to handle the renewable sources (RS) is proposed in this paper. This converter includes two unidirectional input ports accommodating both a fuel cell (FC) and photovoltaic (PV) cell; and one output port with DC load. Due to the inductors at all the ports, it claims the advantage of continuous input and output currents. Additionally, it uses less number of switches, diodes and inductors compared with conventional ‘n-1’ separate Cuk converters. Synthesis procedure for a generalized n-port DC–DC structure is explained. The derivation law based on conventional Cuk converter, operating principle, design calculation, and analysis are presented in detail, and then the analysis is validated through simulation and a 100W prototype, verifying the performance of the proposed NI-TPC converter.
Small-Signal Stability Criteria in AC Distribution Systems—A Review
Authors: Rahman Atta Ur , Syed Irtaza , Ullah Mukhtar
Published: February 2019

AC distribution grid is prone to instability due to negative impedance and constant power nature of the load if it is dominant with power electronics-based components. There are various time-domain and frequency-domain modelling methods which use various methodologies and analytical tools. Also, there are many small-signal stability analysis (SSSA) methods and their different variants for different specific conditions and situation. This paper presents a review of SSSA methods in AC distribution grid using impedance-based models in a synchronous reference frame (SRF). By simplifying and converting the system into load and source subsystem, the impedances of both subsystems are determined by perturbation method. For a single-phase system, Hilbert transform can be used to derive the equivalent SRF model. Afterwards, the Nyquist stability criterion can be used for stability analysis.
Ultra-Short Pulsed Laser Annealing Effects on MoS2 Transistors with Asymmetric and Symmetric Contacts
Authors: Kwon Hyeokjin , Baik Seunghun , Jang Jae Eun , Jang Jaewon , Kim Sunkook , Grigoropoulos Costas P. , Kwon Hyuk-Jun
Published: February 2019

The ultra-short pulsed laser annealing process enhances the performance of MoS2 thin film transistors (TFTs) without thermal damage on plastic substrates. However, there has been insufficient investigation into how much improvement can be brought about by the laser process. In this paper, we observed how the parameters of TFTs, i.e., mobility, subthreshold swing, Ion/Ioff ratio, and Vth, changed as the TFTs’ contacts were (1) not annealed, (2) annealed on one side, or (3) annealed on both sides. The results showed that the linear effective mobility (μeff_lin) increased from 13.14 [cm2/Vs] (not annealed) to 18.84 (one side annealed) to 24.91 (both sides annealed). Also, Ion/Ioff ratio increased from 2.27 × 10 5 (not annealed) to 3.14 × 10 5 (one side annealed) to 4.81 × 10 5   (both sides annealed), with Vth shifting to negative direction. Analyzing the main reason for the improvement through the Y function method (YFM), we found that both the contact resistance (Rc) and the channel interface resistance (Rch) improves after the pulsed laser annealings under different conditions. Moreover, the Rc enhances more dramatically than the Rch does. In conclusion, our picosecond laser annealing improves the performance of TFTs (especially, the Rc) in direct proportion to the number of annealings applied. The results will contribute to the investigation about correlations between the laser annealing process and the performance of devices.
A 5GS/s 8-bit ADC with Self-Calibration in 0.18 μm SiGe BiCMOS Technology
Authors: Wang Dong , Luan Jian , Guo Xuan , Zhou Lei , Wu Danyu , Liu Huasen , Ding Hao , Wu Jin , Liu Xinyu
Published: February 2019

A 5 GS/s 8-bit analog-to-digital converter (ADC) implemented in 0.18 μm SiGe BiCMOS technology has been demonstrated. The proposed ADC is based on two-channel time-interleaved architecture, and each sub-ADC employs a two-stage cascaded folding and interpolating topology of radix-4. An open loop track-and-hold amplifier with enhanced linearity is designed to meet the dynamic performance requirement. The on-chip self-calibration technique is introduced to compensate the interleaving mismatches between two sub-ADCs. Measurement results show that the spurious free dynamic range (SFDR) stays above 44.8 dB with a peak of 53.52 dB, and the effective number of bits (ENOB) is greater than 5.8 bit with a maximum of 6.97 bit up to 2.5 GS/s. The ADC exhibits a differential nonlinearity (DNL) of -0.31/+0.23 LSB (least significant bit) and an integral nonlinearity (INL) of -0.68/+0.68 LSB, respectively. The chip occupies an area of 3.9 × 3.6 mm2, consumes a total power of 2.8 W, and achieves a figure of merit (FoM) of 10 pJ/conversion step.
Combustion and Emission Enhancement of a Spark Ignition Two-Stroke Cycle Engine Utilizing Internal and External Exhaust Gas Recirculation Approach at Low-Load Operation
Authors: Mahmoudzadeh Andwari Amin , Pesyridis Apostolos , Esfahanian Vahid , Said Mohd Farid Muhamad
Published: February 2019

Two-stroke cycle engines have always been prominent due to their distinctive advantage incorporating high power-to-weight ratio, however the drawbacks are poor combustion efficiency, fuel short-circuiting and excessive emission of uHC and CO. These problems are apparent at low-load and speed regions and are the major obstacle to their global acceptance. The deficiencies can be addressed by increasing the in-cylinder average charge temperature employing Exhaust Gas Recirculation (EGR). An experimental study is conducted to investigate the influence of utilizing EGR techniques, including Internal and External EGR, on combustion misfiring occurrence, combustion stability and exhaust emissions using a single cylinder two-stroke SI engine at idling, low and mid-load conditions. From the results, it is observed since the average in-cylinder charge temperature is increased, due to utilizing EGRs, engine’s low and mid-load irregular combustions (misfire) and exhaust emissions are remarkably supressed and almost all of misfire cycles eliminated depending on the percentage of EGRs. In terms of combustion stability, it is agreed in general the application of EGRs improves the cyclic variation of IMEP, Pmax and CA10 compared to conventional operation. However, applying Ex-EGR compared to In-EGR will deteriorate cyclic variability of IMEP and CA10.
Low-Temperature Performance of Al-air Batteries
Authors: Zuo Yuxin , Yu Ying , Zuo Chuncheng , Ning Chuanlong , Liu Hao , Gu Zhiqing , Cao Qianqian , Shen Ciming
Published: February 2019

High demand for batteries with a wide operating temperature range is on the rise with the development of wearable electronic devices, especially electric vehicles used in cold regions. Al–air batteries for electric vehicles have triggered worldwide interest due to their excellent theoretical energy density and safety. In this study, the low-temperature performance of Al–air batteries is tested for the first time. The effects of temperature and electrolyte concentrations on the discharge performance are then studied in detail. The discharge voltage is significantly influenced by the temperature. The low temperature could significantly depress the hydrogen evolution reaction of Al anodes. The Al–air batteries reached an extraordinary capacity of 2480 mAh/g, with 31 wt% KOH electrolyte at −15 °C. Moreover, the Al–air batteries at 0 °C exhibited higher discharge voltage and power densities than those at 15 and −15 °C. This study provides an important reference for future studies to improve low-temperature performance of Al–air batteries.
Proposed Strategies for Improving Poor Hygrothermal Conditions in Museum Exhibition Rooms and Their Impact on Energy Demand
Authors: Ferdyn-Grygierek Joanna , Grygierek Krzysztof
Published: February 2019

In museums, poor microclimate conditions, especially large changes in relative humidity and temperature, can lead to serious deterioration of the exhibits. Properly designed heating, ventilation, and air conditioning (HVAC) systems for precise control of the air parameters are required. However, due to the financial restrictions of museums, complex air-conditioning systems are often not feasible. In this study, we tested and propose novel methods to reduce the short- and long-term fluctuations in the relative humidity in exhibition rooms of a Polish museum. The methods only include indoor temperature and ventilation airflow control strategies, without the use of (de)humidification equipment. The analysis is based on simulations using EnergyPlus software. A multi-zone thermal model of the museum building was validated and calibrated with measured data. A full calendar year was simulated for five control cases (including the current method used) and two internal heat gain schedules. The energy demand for heating and cooling for each case was calculated. The combination of temperature control and adequate ventilation using ambient airflow allows for dramatic improvement in the microclimate conditions. The proportion of the year when the instantaneous indoor relative humidity is ±5% from set point decreased from 85% to 20%. A significant effect was obtained over the summer months.
Stability of Split-Level Gob-Side Entry in Ultra-Thick Coal Seams: A Case Study at Xiegou Mine
Authors: Zhang Junwen
Published: February 2019

Split-level longwall gob-side entry (SLGE) has been applied as a special form of small gate pillar mining (or non-coal pillar mining) in thick coal seams. The stability of the coal pillar directly affects the rationality of the layout of the SLGE. Starting from the mining-induced influence around the SLGE, this paper compares the mechanical properties of coal under different mining effects, and studies the rationality of “zero pillar” location against the Xiegou coal mine. The study shows that the key to success of the application of the SLGE is the existence of an intact zone within the triangular coal pillar in spite of double disturbances due to tunneling and coal mining extraction. Laboratory testing shows that the density and uniaxial compressive strength of rock specimens obtained from the triangular coal pillar are smaller than that from the other part of the panel which is concluded to be due to the varied degree of mining-induced influence. The numerical modeling results show that most of the triangular coal pillar is intact after extraction of the panel, and that the peak stress is located in the solid coal beyond the triangular coal pillar. The plastic zone of the triangular coal pillar is only about 1 m after the excavation of the tail gate of the next split-level panel. The physical modeling shows that the tail gate of the next panel is in the destressed zone with only a very small stress fluctuation during the extraction of the next panel. The study shows that the location of the SLGE at Xiegou coal mine is reasonable. SLGE is preferable for ultra-thick coal seams.
The Effects of Electrification on School Enrollment in Bangladesh: Short- and Long-Run Perspectives
Authors: Alam Mohammad Jahangir , Kaneko Shinji
Published: February 2019

This paper aims to show the impact of access to electricity on school enrollment in Bangladesh. It offers an empirical investigation of the relationship between access to electricity and school enrollment statuses, such as grade progression, repetition, and non-attendance. The data were taken from Bangladesh’s Multiple Indicator Cluster Survey (MICS) database 2012–2013 provided by the Bangladesh Bureau of Statistics (BBS) and UNICEF; the data include two years of grading information for children of ages ranging from 5–15. We applied the propensity score matching (PSM) and the Markov schooling transition model using matched sample data. The results show that access to electricity has a significant positive effect on grade progression and a significant negative effect on non-attendance in the short run as well as in the long run. The simulation result shows that the non-attendance rate is lower and the school enrollment rate for children grades 9-11 is higher in the electrified areas compared to unelectrified areas. This result suggests that access to electricity is an important strategic indicator for increasing school enrollment in both primary and secondary schools.
Experimental Study on Factors Affecting the Performance of Foamy Oil Recovery
Authors: Lv Weifeng , Du Dongxing , Yang Jiru , Jia Ninghong , Li Tong , Wang Rong
Published: February 2019

The flow characteristics of dissolved gas driven processes in some heavy oil reservoirs, such as low gas–oil ratio and higher oil recovery rate than expected, are quite different from conventional oil production processes. Foamy oil is considered one of the main reasons behind such a production phenomenon. In this paper, the factors affecting the performance of foamy oil recovery were experimentally investigated in a sandpack medium with the assistance of computed tomography (CT) technology to help further the understanding of the mechanism. Five different experiments were applied and the results showed that (1) the linear pressure drop production model had a similar oil recovery to that of the step-down mode; (2) increasing the depletion rate could be more favorable to the oil recovery rate; (3) under a constant gas–oil ratio, raising the temperature had little impact on oil recovery, but showed obvious impact on the production curve; and (4) with higher permeability, there were more residual oil at the end of the displacement process. Lastly, a dry gas huff and puff experiment was conducted and the decreased oil saturation was observed in the inlet section, while no obvious effect was remarked in the outlet region of the medium.
Planning of a Resilient Underground Distribution Network Using Georeferenced Data
Authors: Valenzuela Alex , Inga Esteban , Simani Silvio
Published: February 2019

This study describes a practical methodology for a resilient planning and routing of power distribution networks considering real scenarios based on georeferenced data. Customers’ demand and their location are the basis for distribution transformer allocation considering the minimal construction costs and reduction of utility’s budget. MST (Minimum Spanning Tree) techniques are implemented to determine the optimal location of distribution transformers and Medium voltage network routing. Additionally, the allocation of tie points is determined to minimise the total load shedding when unusual and extreme events are faced by the distribution grid, improving reliability and resilience reducing downtime during those events. The proposed methodology provides a coverage of 100%, supplying electricity to the totality of customers within statutory limits during normal and unusual conditions.
Thermo-Electric Energy Storage with Solar Heat Integration: Exergy and Exergo-Economic Analysis
Authors: Fiaschi Daniele , Manfrida Giampaolo , Petela Karolina , Talluri Lorenzo
Published: February 2019

A Thermo-Electric Energy Storage (TEES) system is proposed to provide peak-load support (1–2 daily hours of operation) for distributed users using small/medium-size photovoltaic systems (4 to 50 kWe). The purpose is to complement the PV with a reliable storage system that cancompensate the produc tivity/load mismatch, aiming at off-grid operation. The proposed TEES applies sensible heat storage, using insulated warm-water reservoirs at 120/160 °C, and cold storage at −10/−20 °C (water and ethylene glycol). The power cycle is a trans-critical CO2 unit including recuperation; in the storage mode, a supercritical heat pump restores heat to the hot reservoir, while a cooling cycle cools the cold reservoir; both the heat pump and cooling cycle operate on photovoltaic (PV) energy, and benefit from solar heat integration at low–medium temperatures (80–120 °C). This allows the achievement of a marginal round-trip efficiency (electric-to-electric) in the range of 50% (not considering solar heat integration).The TEES system is analysed with different resource conditions and parameters settings (hot storage temperature, pressure levels for all cycles, ambient temperature, etc.), making reference to standard days of each month of the year; exergy and exergo-economic analyses are performed to identify the critical items in the complete system and the cost of stored electricity.
Identification and Prioritization of Risk Factors in an Electrical Generator Based on the Hybrid FMEA Framework
Authors: Alrifaey Moath , Sai Hong Tang , Supeni Eris Elianddy , As’arry Azizan , Ang Chun Kit
Published: February 2019

The oil and gas industry is looking for ways to accurately identify and prioritize the failure modes (FMs) of the equipment. Failure mode and effect analysis (FMEA) is the most important tool used in the maintenance approach for the prevention of malfunctioning of the equipment. Current developments in the FMEA technique are mainly focused on addressing the drawbacks of the conventional risk priority number calculations, but the group effects and interrelationships of FMs on other measurements are neglected. In the present study, a hybrid distribution risk assessment framework was proposed to fill these gaps based on the combination of modified linguistic FMEA (LFMEA), Analytic Network Process (ANP), and Decision Making Trial and Evaluation Laboratory (DEMATEL) techniques. The hybrid framework of FMEA was conducted in a hazardous environment at a power generation unit in an oil and gas plant located in Yemen. The results show that mechanical and gas leakage FM in electrical generators posed a greater risk, which critically affects other FMs within the plant. It was observed that the suggested framework produced a precise ranking of FMs, with a clear relationship among FMs. Also, the comparisons of the proposed framework with previous studies demonstrated the multidisciplinary applications of the present framework.
3D-Basin Modelling of the Lishui Sag: Research of Hydrocarbon Potential, Petroleum Generation and Migration
Authors: Zhang Jinliang , Guo Jiaqi , Liu Jinshui , Shen Wenlong , Li Na , Xu Guangchen
Published: February 2019

The Lishui Sag is located in the southeastern part of the Taibei Depression, in the East China Sea basin, where the sag is the major hydrocarbon accumulation zone. A three dimensional modelling approach was used to estimate the mass of petroleum generation and accumulated during the evolution of the basin. Calibration of the model, based on measured maturity (vitrinite reflectance) and borehole temperatures, took into consideration two main periods of erosion events: a late Cretaceous to early Paleocene event, and an Oligocene erosion event. The maturation histories of the main source rock formations were reconstructed and show that the peak maturities have been reached in the west central part of the basin. Our study included source rock analysis, measurement of fluid inclusion homogenization temperatures, and basin history modelling to define the source rock properties, the thermal evolution and hydrocarbon generation history, and possible hydrocarbon accumulation processes in the Lishui Sag. The study found that the main hydrocarbon source for the Lishui Sag are argillaceous source rocks in the Yueguifeng Formation. The hydrocarbon generation period lasted from 58 Ma to 32 Ma. The first period of hydrocarbon accumulation lasted from 51.8 Ma to 32 Ma, and the second period lasted from 23 Ma to the present. The accumulation zones mainly located in the structural high and lithologic-fault screened reservoir filling with the hydrocarbon migrated from the deep sag in the south west direction.
Synthesis and Optimal Operation of Smart Microgrids Serving a Cluster of Buildings on a Campus with Centralized and Distributed Hybrid Renewable Energy Units
Authors: Testi Daniele , Conti Paolo , Schito Eva , Urbanucci Luca , D’Ettorre Francesco
Published: February 2019

Micro-district heating networks based on cogeneration plants and renewable energy technologies are considered efficient, viable and environmentally-friendly solutions to realizing smart multi-energy microgrids. Nonetheless, the energy production from renewable sources is intermittent and stochastic, and cogeneration units are characterized by fixed power-to-heat ratios, which are incompatible with fluctuating thermal and electric demands. These drawbacks can be partially overcome by smart operational controls that are capable of maximizing the energy system performance. Moreover, electrically driven heat pumps may add flexibility to the system, by shifting thermal loads into electric loads. In this paper, a novel configuration for smart multi-energy microgrids, which combines centralized and distributed energy units is proposed. A centralized cogeneration system, consisting of an internal combustion engine is connected to a micro-district heating network. Distributed electric heat pumps assist the thermal production at the building level, giving operational flexibility to the system and supporting the integration of renewable energy technologies, i.e., wind turbines, photovoltaic panels, and solar thermal collectors. The proposed configuration was tested in a hypothetical case study, namely, a University Campus located in Trieste, Italy. The system operation is based on a cost-optimal control strategy and the effect of the size of the cogeneration unit and heat pumps was investigated. A comparison with a conventional configuration, without distributed heat pumps, was also performed. The results show that the proposed configuration outperformed the conventional one, leading to a total-cost saving of around 8%, a carbon emission reduction of 11%, and a primary energy saving of 8%.
Design and Control of Coupled Inductor DC–DC Converters for MVDC Ship Power Systems
Authors: Balsamo Flavio , Lauria Davide , Mottola Fabio
Published: February 2019

This paper deals with the design and control aspects of modern ship power systems within the paradigm of an all-electric ship. The widespread use of power electronic converters is central in this context due to the technological advances in automation systems and the integration of the electrical propulsion systems and other components, such as electrical energy storage systems and renewable energy sources. The issue to address in this scenario is related to the request of increased performances in dynamic operation while pursuing advantages in terms of energy savings and overall system security. In addition, the presence of large load changes requires providing robustness of the control in terms of system stability. This paper is focused on medium voltage direct current (MVDC) ship power systems and the design and control of coupled inductor DC–DC converters. The load is handled in terms of a constant power model, which generally is considered the most critical case for testing the stability of the system. The robustness of the design procedure, which is verified numerically against large and rapid load variations, allowed us to confirm the feasibility and the attractiveness of the design and the control proposal.
Driving Forces of Energy-Related CO2 Emissions Based on Expanded IPAT Decomposition Analysis: Evidence from ASEAN and Four Selected Countries
Authors: Chontanawat Jaruwan
Published: February 2019

ASEAN is a dynamic and diverse region which has experienced rapid urbanization and population growth. Their energy demand grew by 60% in the last 15 years. In 2013, about 3.6% of global greenhouse-gas emissions was emitted from this region and the share is expected to rise substantially. Hence, a better understanding of driving forces of the changes in CO2 emissions is important to tackle global climate change and develop appropriate policies. Using IPAT combined with variance analysis, this study aims to identify the main driving factors of CO2 emissions for ASEAN and four selected countries (Indonesia, Malaysia, Philippines and Thailand) during 1971–2013. The results show that population growth and economic growth were the main driving factors for increasing CO2 emissions for most of the countries. Fossil fuels play an important role in increasing CO2 emissions, however the growth in emissions was compensated by improved energy efficiency and carbon intensity of fossil energy. The results imply that to decouple energy use from high levels of emissions is important. Proper energy management through fuel substitution and decreasing emission intensity through technological upgrades have considerable potential to cut emissions.
Modelling Load Profiles of Heat Pumps
Authors: Conrad Jochen , Greif Simon
Published: February 2019

Approximately one quarter of energy-related emissions in Germany are caused by the domestic sector. At 81%, the largest share of these emissions is due to heat supply. Many measures are available to reduce these emissions. One of these measures, which is considered to play an important role in many studies, is the replacement of fossil-fired boilers with electric heat pumps. In order to be able to analyse the impact of high penetrations of heat pumps on the energy system, the coefficient of performance (COP) must be modelled with high temporal resolution. In this study, a methodology is presented on how to calculate high-resolution COPs and the electrical load of heat pumps based on thermal load curves and temperature time series. The COP is determined by the reciprocal Carnot factor. Since heat pumps are often designed bivalently due to the cost structure, the methodology described can also be used for evaluating the combination of immersion heater and heat pump (here for the air/water heat pump). As a result the theoretical hourly COPs determined are calibrated with annual performance factors from field tests. The modelled COPs show clear differences. Currently, mostly air source heat pumps are installed in Germany. If this trend continues, the maximum electrical load of the heat supply will increase more than would be the case with higher shares of ground source heat pumps.
Energy Embedded in Food Loss Management and in the Production of Uneaten Food: Seeking a Sustainable Pathway
Authors: Hoehn Daniel , Margallo María , Laso Jara , García-Herrero Isabel , Bala Alba , Fullana-i-Palmer Pere , Irabien Angel , Aldaco Rubén
Published: February 2019

Recently, important efforts have been made to define food loss management strategies. Most strategies have mainly been focused on mass and energy recovery through mixed food loss in centralised recovery models. This work aims to highlight the need to address a decentralised food loss management, in order to manage the different fractions and on each of the different stages of the food supply chain. For this purpose, an energy flow analysis is made, through the calculation of the primary energy demand of four stages and 11 food categories of the Spanish food supply chain in 2015. The energy efficiency assessment is conducted under a resource use perspective, using the energy return on investment (EROI) ratio, and a circular economy perspective, developing an Energy return on investment – Circular economy index (EROIce), based on a food waste-to-energy-to-food approach. Results suggest that the embodied energy loss consist of 17% of the total primary energy demand, and related to the food categories, the vegetarian diet appears to be the most efficient, followed by the pescetarian diet. Comparing food energy loss values with the estimated energy provided for one consumer, it is highlighted the fact that the food energy loss generated by two to three persons amounts to one person's total daily intake. Moreover, cereals is the category responsible for the highest percentage on the total food energy loss (44%); following by meat, fish and seafood and vegetables. When the results of food energy loss and embodied energy loss are related, it is observed that categories such as meat and fish and seafood have a very high primary energy demand to produce less food, besides that the parts of the food supply chain with more energy recovery potential are the beginning and the end. Finally, the EROIce analysis shows that in the categories of meat, fish and seafood and cereals, anaerobic digestion and composting is the best option for energy recovery. From the results, it is discussed the possibility to developed local digesters at the beginning and end of the food supply chain, as well as to developed double digesters installations for hydrogen recovery from cereals loss, and methane recovery from mixed food loss.
Thermal Insulating and Mechanical Properties of Cellulose Nanofibrils Modified Polyurethane Foam Composite as Structural Insulated Material
Authors: Leng Weiqi , Pan Biao
Published: February 2019

Cellulose nanofibrils (CNF) modified polyurethane foam (PUF) has great potential as a structural insulated material in wood construction industry. In this study, PUF modified with spray-dried CNF was fabricated and the physical and mechanical performance were studied. Results showed that CNF had an impact on the foam microstructure by increasing the precursor viscosity and imposing resistant strength upon foaming. In addition, the intrinsic high mechanical strength of CNF imparted an extra resistant force against cells expansion during the foaming process and formed smaller cells which reduced the chance of creating defective cells. The mechanical performance of the foam composite was significantly improved by introducing CNF into the PUF matrix. Compared with the PUF control, the specific bending strength, specific tensile strength, and specific compression strength increased up to three-fold for the CNF modified PUF. The thermal conductivity of PUF composite was mainly influenced by the closed cell size. The introduction of CNF improved thermal insulating performance, with a decreased thermal conductivity from 0.0439 W/mK to 0.02724 W/mK.
Pesticide Residues and Stuck Fermentation in Wine: New Evidences Indicate the Urgent Need of Tailored Regulations
Authors: Russo Pasquale , Berbegal Carmen , De Ceglie Cristina , Grieco Francesco , Spano Giuseppe , Capozzi Vittorio
Published: February 2019

For three consecutive years, an Italian winery in Apulia has dealt with sudden alcoholic stuck fermentation in the early stages of vinification process, i.e., typical defects addressable to bacterial spoilage. After a prescreening trial, we assessed, for the first time, the influence of the commercial fungicide preparation Ridomil Gold® (Combi Pepite), containing Metalaxyl-M (4.85%) and Folpet (40%) as active principles, on the growth of several yeasts (Saccharomyces cerevisiae and non-Saccharomyces spp.) and lactic acid bacteria of oenological interest. We also tested, separately and in combination, the effects of Metalaxyl-M and Folpet molecules on microbial growth both in culture media and in grape must. We recalled the attention on Folpet negative effect on yeasts, extending its inhibitory spectrum on non-Saccharomyces (e.g., Candida spp.). Moreover, we highlighted a synergic effect of Metalaxyl-M and Folpet used together and a possible inhibitory role of the fungicide excipients. Interestingly, we identified the autochthonous S. cerevisiae strain E4 as moderately resistant to the Folpet toxicity. Our findings clearly indicate the urgent need for integrating the screening procedures for admission of pesticides for use on wine grape with trials testing their effects on the physiology of protechnological microbes.
Fire Risk Assessment of Combustible Exterior Cladding Using a Collective Numerical Database
Authors: Chen Timothy Bo Yuan , Yuen Anthony Chun Yin , Yeoh Guan Heng , Yang Wei , Chan Qing Nian
Published: February 2019

Recent high-profile building fires involving highly-combustible external cladding panels in Australia as well as Dubai, China, and the United Kingdom have created a heightened awareness by the public, government, and commercial entities to act on the risks associated with non-compliant building structures. In this paper, a database of fire events involving combustible aluminium composite panels was developed based on (i) review of relevant major fire events in Australia and other countries, and (ii) numerical simulation of the ignitability, fire spread, and toxic emissions associated with composite panels. Through the application of large-eddy-simulation (LES)-based computational fire field models, the associated risks for a standardized two-storey building with external cladding was considered in this study. A total of sixteen simulation cases with different initial sizes of the fire and different air cavity widths in the exterior cladding assembly were examined to investigate the tolerable situations and their influences. It was discovered that for most cases, with an initial fire size greater than 400 kW/m−2, the fire will spread from the first to second floor before the allowed egress time period.
Bacterial Production and Control of Biogenic Amines in Asian Fermented Soybean Foods
Authors: Mah Jae-Hyung , Park Young , Jin Young , Lee Jun-Hee , Hwang Han-Joon
Published: February 2019

Fermented soybean foods possess significant health-promoting effects and are consumed worldwide, especially within Asia, but less attention has been paid to the safety of the foods. Since fermented soybean foods contain abundant amino acids and biogenic amine-producing microorganisms, it is necessary to understand the presence of biogenic amines in the foods. The amounts of biogenic amines in most products have been reported to be within safe levels. Conversely, certain products contain vasoactive biogenic amines greater than toxic levels. Nonetheless, government legislation regulating biogenic amines in fermented soybean foods is not found throughout the world. Therefore, it is necessary to provide strategies to reduce biogenic amine formation in the foods. Alongside numerous existing intervention methods, the use of Bacillus starter cultures capable of degrading and/or incapable of producing biogenic amines has been proposed as a guaranteed way to reduce biogenic amines in fermented soybean foods, considering that Bacillus species have been known as fermenting microorganisms responsible for biogenic amine formation in the foods. Molecular genetic studies of Bacillus genes involved in the formation and degradation of biogenic amines would be helpful in selecting starter cultures. This review summarizes the presence and control strategies of biogenic amines in fermented soybean foods.
Fractal Image Interpolation: A Tutorial and New Result
Authors: Kok Chi Wah , Tam Wing Shan
Published: February 2019

This paper reviews the implementation of fractal based image interpolation, the associated visual artifacts of the interpolated images, and various techniques, including novel contributions, that alleviate these awkward visual artifacts to achieve visually pleasant interpolated image. The fractal interpolation methods considered in this paper are based on the plain Iterative Function System (IFS) in spatial domain without additional transformation, where we believe that the benefits of additional transformation can be added onto the presented study without complication. Simulation results are presented to demonstrate the discussed techniques, together with the pros and cons of each techniques. Finally, a novel spatial domain interleave layer has been proposed to add to the IFS image system for improving the performance of the system from image zooming to interpolation with the preservation of the pixel intensity from the original low resolution image.
Calcium-Dependent RTX Domains in the Development of Protein Hydrogels
Authors: Bulutoglu Beyza , Banta Scott
Published: February 2019

The RTX domains found in some pathogenic proteins encode repetitive peptide sequences that reversibly bind calcium and fold into the unique the β-roll secondary structure. Several of these domains have been studied in isolation, yielding key insights into their structure/function relationships. These domains are increasingly being used in protein engineering applications, where the calcium-induced control over structure can be exploited to gain new functions. Here we review recent advances in the use of RTX domains in the creation of calcium responsive biomaterials.
Supramolecular Strategy Effects on Chitosan Bead Stability in Acidic Media: A Comparative Study
Authors: Worthen Andrew J. , Irving Kelly S. , Lapitsky Yakov
Published: February 2019

Chitosan beads attract interest in diverse applications, including drug delivery, biocatalysis and water treatment. They can be formed through several supramolecular pathways, ranging from phase inversion in alkaline solutions, to the ionic crosslinking of chitosan with multivalent anions, to polyelectrolyte or surfactant/polyelectrolyte complexation. Many chitosan bead uses require control over their stability to dissolution. To help elucidate how this stability depends on the choice of supramolecular gelation chemistry, we present a comparative study of chitosan bead stability in acidic aqueous media using three common classes of supramolecular chitosan beads: (1) alkaline solution-derived beads, prepared through simple precipitation in NaOH solution; (2) ionically-crosslinked beads, prepared using tripolyphosphate (TPP); and (3) surfactant-crosslinked beads prepared via surfactant/polyelectrolyte complexation using sodium salts of dodecyl sulfate (SDS), caprate (NaC10) and laurate (NaC12). Highly variable bead stabilities with dissimilar sensitivities to pH were achieved using these methods. At low pH levels (e.g., pH 1.2), chitosan/SDS beads were the most stable, requiring roughly 2 days to dissolve. In weakly acidic media (at pH 3.0–5.0), however, chitosan/TPP beads exhibited the highest stability, remaining intact throughout the entire experiment. Beads prepared using only NaOH solution (i.e., without ionic crosslinking or surfactant complexation) were the least stable, except at pH 5.0, where the NaC10 and NaC12-derived beads dissolved slightly faster. Collectively, these findings provide further guidelines for tailoring supramolecular chitosan bead stability in acidic media.