bluuebunny/crossref_metadata_2025 huggingface dataset:
Shielding Properties of Cement Composites Filled with Commercial Biochar
Authors: Yasir Muhammad , di Summa Davide , Ruscica Giuseppe , Natali Sora Isabella , Savi Patrizia
Published: May 2020

The partial substitution of non-renewable materials in cementitious composites with eco-friendly materials is promising not only in terms of cost reduction, but also in improving the composites’ shielding properties. The water and carbon content of a commercial lignin-based biochar is analyzed with thermal gravimetric analysis. Cementitious composite samples of lignin-based biochar with 14 wt.% and 18 wt.% are realized. Good dispersion of the filler in the composites is observed by SEM analysis. The samples are fabricated in order to fit in a rectangular waveguide for measurements of the shielding effectiveness in the X-band. A shielding effectiveness of 15 dB was obtained at a frequency of 10 GHz in the case of composites with 18 wt.% biochar. Full-wave simulations are performed by fitting the measured shielding effectiveness to the simulated shielding effectiveness by varying material properties in the simulator. Analysis of the dimensional tolerances and thickness of the samples is performed with the help of full/wave simulations. Lignin-based biochar is a good candidate for partial substitution of cement in cementitious composites, as the shielding effectiveness of the composites increases substantially.
Reducing the Delay for Decoding Instructions by Predicting Their Source Register Operands
Authors: Park Sanghyun , Jun Jaeyung , Kim Changhyun , Min Gyeong Il , Lee Hun Jae , Kim Seon Wook
Published: May 2020

The fetched instructions would have data dependency with in-flight ones in the pipeline execution of a processor, so the dependency prevents the processor from executing the incoming instructions for guaranteeing the program’s correctness. The register and memory dependencies are detected in the decode and memory stages, respectively. In a small embedded processor that supports as many ISAsas possible to reduce code size, the instruction decoding to identify register usage with the dependence check generally results in long delay and sometimes a critical path in its implementation. For reducing the delay, this paper proposes two methods—One method assumes the widely used source register operand bit-fields without fully decoding the instructions. However, this assumption would cause additional stalls due to the incorrect prediction; thus, it would degrade the performance. To solve this problem, as the other method, we adopt a table-based way to store the dependence history and later use this information for more precisely predicting the dependency. We applied our methods to the commercial EISC embedded processor with the Samsung 65nm process; thus, we reduced the critical path delay and increased its maximum operating frequency by 12.5% and achieved an average 11.4% speed-up in the execution time of the EEMBC applications. We also improved the static, dynamic power consumption, and EDP by 7.2%, 8.5%, and 13.6%, respectively, despite the implementation area overhead of 2.5%.
Machine Learning Techniques for Assistive Robotics
Authors: Martinez-Martin Ester , Cazorla Miguel , Orts-Escolano Sergio
Published: May 2020

Assistive robots are a category of robots that share their area of work and interact with humans [...]
Detecting Predictable Segments of Chaotic Financial Time Series via Neural Network
Authors: Zhou Tianle , Chu Chaoyi , Xu Chaobin , Liu Weihao , Yu Hao
Published: May 2020

In this study, a new idea is proposed to analyze the financial market and detect price fluctuations, by integrating the technology of PSR (phase space reconstruction) and SOM (self organizing maps) neural network algorithms. The prediction of price and index in the financial market has always been a challenging and significant subject in time-series studies, and the prediction accuracy or the sensitivity of timely warning price fluctuations plays an important role in improving returns and avoiding risks for investors. However, it is the high volatility and chaotic dynamics of financial time series that constitute the most significantly influential factors affecting the prediction effect. As a solution, the time series is first projected into a phase space by PSR, and the phase tracks are then sliced into several parts. SOM neural network is used to cluster the phase track parts and extract the linear components in each embedded dimension. After that, LSTM (long short-term memory) is used to test the results of clustering. When there are multiple linear components in the m-dimension phase point, the superposition of these linear components still remains the linear property, and they exhibit order and periodicity in phase space, thereby providing a possibility for time series prediction. In this study, the Dow Jones index, Nikkei index, China growth enterprise market index and Chinese gold price are tested to determine the validity of the model. To summarize, the model has proven itself able to mark the unpredictable time series area and evaluate the unpredictable risk by using 1-dimension time series data.
A Comparative Analysis of Cyber-Threat Intelligence Sources, Formats and Languages
Authors: Ramsdale Andrew , Shiaeles Stavros , Kolokotronis Nicholas
Published: May 2020

The sharing of cyber-threat intelligence is an essential part of multi-layered tools used to protect systems and organisations from various threats. Structured standards, such as STIX, TAXII and CybOX, were introduced to provide a common means of sharing cyber-threat intelligence and have been subsequently much-heralded as the de facto industry standards. In this paper, we investigate the landscape of the available formats and languages, along with the publicly available sources of threat feeds, how these are implemented and their suitability for providing rich cyber-threat intelligence. We also analyse at a sample of cyber-threat intelligence feeds, the type of data they provide and the issues found in aggregating and sharing the data. Moreover, the type of data supported by various formats and languages is correlated with the data needs for several use cases related to typical security operations. The main conclusions drawn by our analysis suggest that many of the standards have a poor level of adoption and implementation, with providers opting for custom or traditional simple formats.
The Detection of Chemical Materials with a Metamaterial-Based Sensor Incorporating Oval Wing Resonators
Authors: Abdulkarim Yadgar , Deng Lianwen , Karaaslan Muharrem , Dalgaç Şekip , Mahmud Rashad , Ozkan Alkurt Fatih , Muhammadsharif Fahmi , Awl Halgurd , Huang Shengxiang , Luo Heng
Published: May 2020

The detection of branded and unbranded chemical materials is essential for the quality control assessment. In this work, a metamaterial inspired sensor is designed and fabricated, which incorporates oval-shaped wing resonators, in order to use to detect branded and unbranded diesels in the X-band frequency region. The simulation studies were carried out by using the Computer Simulation Technology (CST) Microwave studio. A transmission line was introduced into the sensor design and genetic algorithm was used to optimize the proposed structure. Parametric study was investigated by changing the permittivity, permeability of the sensor layer, width of the transmission line, materials of the substrate layer, and width of the resonator. Results showed that different factors can be considered to sense the chemical materials including the shift in resonant frequency and amplitude variation in the reflection or transmission spectrum. It was found that the sensible variation in the transmission value is about −3.2 dB, which is superior to that reported in literature. It was concluded that the sensor is highly sensitive to distinguish the branded diesel from the unbranded one, which makes it viable for detecting fluidics in the chemical industry and medicine.
Enabling Multiple Access in Visible Light Communication Using Liquid Crystal Displays: A Proof-of-Concept Study
Authors: Rahman MD Rashed , Adedara Kehinde , Ashok Ashwin
Published: May 2020

The directionality of optical signals provides an opportunity for efficient space reuse of optical links in visible light communication (VLC). Space reuse in VLC can enable multiple-access communication from multiple light emitting transmitters. Traditional VLC system design using photo-receptors requires at least one receiving photodetector element for each light emitter, thus constraining VLC to always require a light-emitter to light-receptor element pair. In this paper, we propose, design and evaluate a novel architecture for VLC that can enable multiple-access reception using a photoreceptor receiver that uses only a single photodiode. The novel design includes a liquid-crystal-display (LCD) based shutter system that can be automated to control and enable selective reception of light beams from multiple transmitters. We evaluate the feasibility of multiple access on a single photodiode from two light emitting diode (LED) transmitters and the performance of the communication link using bit-error-rate (BER) and packet-error-rate (PER) metrics. Our experiment and trace based evaluation through proof-of-concept implementation reveals the feasibility of multiple LED reception on a single photodiode. We further evaluate the system in controlled mobile settings to verify the adaptability of the receiver when the LED transmitter changes position.
A Container Orchestration Development that Optimizes the Etherpad Collaborative Editing Tool through a Novel Management System
Authors: Tapia Freddy , Mora Miguel Ángel , Fuertes Walter , Lascano Jorge Edison , Toulkeridis Theofilos
Published: May 2020

The use of collaborative tools has notably increased recently. It is common to see distinct users that need to work simultaneously on shared documents. In most cases, large companies provide tools whose implementations have been a very complicated and expensive task. Likewise, their platform deployment requirements should be robust hardware infrastructures. It becomes even more critical when their main target is to reach scalability and highavailability. Therefore, this study aims to design and implement a microservices-based collaborative architecture using assembled containers in the cloud, enabling them to deploy Etherpad instances to guarantee high availability. To ensure such a task, we developed and optimized a central management system that creates Etherpad instances and continuously interacts with other Etherpad tools running on Docker containers. This design goes from the monolithic Etherpad instantiation and handling towards a service architecture, where every Etherpad is offered as a microservice. Furthermore, the management system follows (implements) the Observer, Factory Method, Proxy, and Service Layerpopular design patterns. This allows users to gain more privacy through access to validations and shared resources. Our results indicate both the correct operation in the automation of containers’ creation for new users who register in the system and quantifiable improvement in performance.
Terahertz Synthetic Aperture Imaging with a Light Field Imaging System
Authors: Lyu Nanfang , Zuo Jian , Zhao Yuanmeng , Zhang Cunlin
Published: May 2020

In terahertz imaging systems based on Gaussian beam active illumination and focal plane array detectors, severe image distortion has been observed, which significantly reduces the resolving power of the imaging system. To solve this problem, a novel computational method, Light Field Imaging (LFI), has been introduced for terahertz imaging. A conventional transmission-type terahertz imaging system based on a gas-pumped terahertz source and terahertz Focal Plane Array Detectors (FPA) arrays is established to analyze the problem of image distortion. An experimental virtual camera array terahertz LFI system is also established. With the acquisition and reconstruction of synthetic aperture terahertz light fields, the improvement on resolving power and SNR performance have been validated.
Experimental Study on the Characteristics of Activated Coal Gangue and Coal Gangue-Based Geopolymer
Authors: Zhang Weiqing , Dong Chaowei , Huang Peng , Sun Qiang , Li Meng , Chai Jun
Published: May 2020

Coal gangue-based geopolymer (CGGP) is one of the hot spots existing in the recycling of coal gangue resources due to its good comprehensive mechanical properties. However, the coal gangue structure is stable and reactivity is poor, so the coal gangue needs to be activated before utilization. In this paper, the microstructure changes of activated coal gangue by different mechanical and thermal activation methods, as well as the mechanical properties and microstructure changes of the CGGP specimens were studied by experimental investigation. The results indicated that mechanical activation and thermal activation were two effective methods to change the reactivity of coal gangue, which consisted of destroying the stable kaolinite structure and improving the activity of coal gangue. Conversely, part of the amorphous structure in coal gangue was destroyed when the activation temperature reached 900 °C, which was not conducive to the further enhancement of coal gangue activity. For the CGGP prepared by thermally activated coal gangue and modified sodium silicate alkali solution, the uniaxial compressive strength of the CGGP specimens decreased with thermal activation temperatures of the raw coal gangue materials at 700 °C, 800 °C, and 900 °C. The main reason for this was the lower amount of the active metakaolin structure in coal gangue at 900 °C, which was not conducive to the geopolymerization process.
An Iterative Refining Approach to Design the Control of Wave Energy Converters with Numerical Modeling and Scaled HIL Testing
Authors: Delmonte Nicola , Robles Eider , Cova Paolo , Giuliani Francesco , Faÿ François Xavier , Lopez Joseba , Ruol Piero , Martinelli Luca
Published: May 2020

The aim of this work is to show that a significant increase of the efficiency of a Wave Energy Converter (WEC) can be achieved already at an early design stage, through the choice of a turbine and control regulation, by means of an accurate Wave-to-Wire (W2W) modeling that couples the hydrodynamic response calibrated in a wave flume to a Hardware-In-the-Loop (HIL) test bench with sizes and rates not matching those of the system under development. Information on this procedure is relevant to save time, because the acquisition, the installation, and the setup of a test rig are not quick and easy. Moreover, power electronics and electric machines to emulate turbines and electric generators matching the real systems are not low-cost equipment. The use of HIL is important in the development of WECs also because it allows the carrying out of tests in a controlled environment, and this is again time- and money-saving if compared to tests done on a real system installed at the sea. Furthermore, W2W modeling can be applied to several Power Take-Off (PTO) configurations to experiment different control strategies. The method here proposed, concerning a specific HIL for testing power electronics and control laws for a specific WECs, may have a more general validity.
Active Shielding Applied to an Electrified Road in a Dynamic Wireless Power Transfer (WPT) System
Authors: Cruciani Silvano , Campi Tommaso , Maradei Francesca , Feliziani Mauro
Published: May 2020

An active coil system is proposed to shield the magnetic field produced by a dynamic wireless power transfer (WPT) system used to power electric vehicles (EVs) in motion. The considered dynamic WPT is based on an electrified road with many short-track pads. A sophisticated mathematical procedure is developed to optimize the design of the active coils configuration and their excitation. By the proposed approach, the resulting magnetic field is compliant with the reference levels (RLs) of the ICNIRP (International Commission on Non-Ionizing Radiation Protection) 2010 Guidelines inside the cabin of EVs and on the side of the electrified road.
Time-Series PV Hosting Capacity Assessment with Storage Deployment
Authors: Bartecka Magdalena , Barchi Grazia , Paska Józef
Published: May 2020

Europe aims to diversify energy sources and reduce greenhouse gas emissions. On this field, large PV power growth is observed that may cause problems in existing networks. This paper examines the impact of distributed PV systems on voltage quality in a low voltage feeder in terms of the European standard EN 50160. As the standard defines allowable percentage of violation during one week period, time-series analyses are done to assess PV hosting capacity. The simulations are conducted with 10-minute step and comprise variable load profiles based on Gaussian Mixture Model and PV profiles based on a distribution with experimentally obtained parameters. In addition, the outcomes are compared with “snapshot” simulations. Next, it is examined how energy storage utilization affects the hosting capacity. Several deployments of energy storages are presented with different number and capacity. In particular, a greedy algorithm is proposed to determine the sub-optimal energy storage deployment based on the voltage deviation minimization. The simulations show that time-series analyses in comparison with snapshot analyses give completely different results and change the level of PV hosting capacity. Moreover, incorrect energy storage capacity selection and location may cause even deterioration of power quality in electrical systems with high RES penetration.
Cross-Country Comparison of Hourly Electricity Mixes for EV Charging Profiles
Authors: Noussan Michel , Neirotti Francesco
Published: May 2020

Electric vehicles, when coupled to electricity generation from renewable energy sources, can become a viable solution to decarbonize the transport sector. However, given the high variability of electricity mixes on a daily and seasonal basis, high-resolution profiles are needed for a precise analysis of the impacts of electric vehicles in terms of greenhouse gases emissions. This paper presents a comparison of different charging profiles evaluated on 10 European countries over four years, to highlight the effects of national electricity mixes and of the type of charging location on the specific emissions of EVs charging. This study, based on three archetypal charging profiles, provide a quantification of the potential influence of different charging strategies on the average emission factor of the electricity supplied to electric vehicles. The results show that the variability related to charging profiles is generally limited, with an average variation range of 6% for any given country and year, while in several countries the variability from one year to another is much larger, with an average range of 18% for any given country and charging profile.
Review of Potential and Actual Penetration of Solar Power in Vietnam
Authors: Riva Sanseverino Eleonora , Le Thi Thuy Hang , Pham Manh-Hai , Di Silvestre Maria Luisa , Nguyen Quang Ninh , Favuzza Salvatore
Published: May 2020

With the average solar radiation reaching up to 5 kWh/m2, Vietnam is considered as a country showing an excellent potential for solar power production. Since the year 2000, there have been a lot of studies about the potential of this source in Vietnam. So far, many applications of solar power have been implemented on small, medium, and large scales. In fact, the total capacity of current grid-connected solar power plants has exceeded the planned capacity by 2020 nearly 6 times. However, the studies of solar potential in Vietnam are still incomplete. The policies and mechanisms for developing solar power projects have received attention from the authorities but have not been really satisfactory. The infrastructure is still poor and the power system does not keep up with the development of modern grids. This paper reviewed the potential and actual implementation stage of photovoltaic projects in Vietnam. Moreover, the barriers and challenges of institution, technique, economy, and finance have been considered explicitly for the future development of solar energy in Vietnam.
Renewable Energy Integration for Steam Supply of Industrial Processes—A Food Processing Case Study
Authors: Hechelmann Ron-Hendrik , Seevers Jan-Peter , Otte Alexander , Sponer Jan , Stark Matthias
Published: May 2020

This study highlights the C O 2 , e -emission reduction potentials and related economic consequences for changing steam generation from fossil to renewable. Seven different utility concepts are developed, including a steam accumulator for load management. Peculiarities for the integration of biogas boilers, biomass-fuelled boilers, electrode steam boilers, biomethane-fuelled solid oxide fuel cells, micro gas turbine, solar energy systems, heat pumps and steam accumulators into a steam system with fluctuating steam demand are explained and the energy balance based models for the simulation study are described. The characteristics of batch processes, start up times and part load efficiency are considered via an annual dynamic simulation. Based on a detailed process analysis and dimensioning of the utilities and the accumulator a comprehensive simulation study is conducted for a pet food processing company having an average steam demand of 18,000 MWh at around 9 bar and 3 t/h. The results show that the highest C O 2 , e -emissions reduction of up to 63% is achieved by the transition to a solid biomass-fuelled boiler system. This leads to an increase of the operating costs by 27.8%.
Effect of Single-Row and Double-Row Passive Vortex Generators on the Deep Dynamic Stall of a Wind Turbine Airfoil
Authors: Zhu Chengyong , Wang Tongguang , Chen Jie , Zhong Wei
Published: May 2020

Passive vortex generators (VGs) have been widely applied on wind turbines to boost the aerodynamic performance. Although VGs can delay the onset of static stall, the effect of VGs on dynamic stall is still incompletely understood. Therefore, this paper aims at investigating the deep dynamic stall of NREL S809 airfoil controlled by single-row and double-row VGs. The URANS method with VGs fully resolved is used to simulate the unsteady airfoil flow. Firstly, both single-row and double-row VGs effectively suppress the flow separation and reduce the fluctuations in aerodynamic forces when the airfoil pitches up. The maximum lift coefficient is therefore increased beyond 40%, and the onset of deep dynamic stall is also delayed. This suggests that deep dynamic-stall behaviors can be properly controlled by VGs. Secondly, there is a great difference in aerodynamic performance between single-row and double-row VGs when the airfoil pitches down. Single-row VGs severely reduce the aerodynamic pitch damping by 64%, thereby undermining the torsional aeroelastic stability of airfoil. Double-row VGs quickly restore the decreased aerodynamic efficiency near the maximum angle of attack, and also significantly accelerate the flow reattachment. The second-row VGs can help the near-wall flow to withstand the adverse pressure gradient and then suppress the trailing-edge flow separation, particularly during the downstroke process. Generally, double-row VGs are better than single-row VGs concerning controlling deep dynamic stall. This work also gives a performance assessment of VGs in controlling the highly unsteady aerodynamic forces of a wind turbine airfoil.
Numerical Investigation of the Required Quantity of Inert Gas Agents in Fire Suppression Systems
Authors: Hu Xiaoqin , Kraaijeveld Arjen , Log Torgrim
Published: May 2020

Inert gas agents have the potential to be widely used in fire suppression systems due to health and safety concerns associated with active chemicals. To suppress fire while minimizing hypoxic effects in an occupied area, the discharge quantity of inert gas agents should be carefully designed to dilute the oxygen concentration to a specific threshold level. In this study, the general expressions between oxygen concentration, the discharge rate of inert gas agents, and the ventilation rate of the air-agent mixture are derived first. Then, explicit formulas to calculate the discharge/ventilation rate and the required quantity of inert gas agents are given if the discharge rate and ventilation rate both are constants. To investigate the dilution and fire extinguishing efficiencies of inert gas agents, two scenarios with a discharge of inert gas agents into an enclosure are modeled using the Fire Dynamic Simulator (FDS). The simulation results show that the average oxygen mass fraction approximately reaches the design level at the end of the discharge period. Variation in oxygen concentration along the enclosure height is analyzed. For the scenario with a fire source, oxygen mass fraction decreases fast as oxygen is consumed by the combustion process. Thus, the fire is extinguished a little earlier than the end of the discharge period.
Effects of Forces, Particle Sizes, and Moisture Contents on Mechanical Behaviour of Densified Briquettes from Ground Sunflower Stalks and Hazelnut Husks
Authors: Demirel Cimen , Gürdil Gürkan Alp Kağan , Kabutey Abraham , Herak David
Published: May 2020

Using the uniaxial compression process, the mechanical behaviour of densified briquettes from ground sunflower stalks and hazelnut husks was studied under different forces (100, 200, 300, and 400 kN), particle sizes (0, 3, 6, and 10 mm), and moisture contents (sunflower; 11.23%, 14.44%, and 16.89% w.b.) and (hazelnut; 12.64%, 14.83%, and 17.34% w.b.) at a constant speed of 5 mm min−1. For each test, the biomass material was compacted at a constant volume of 28.27 × 10−5 m3 using a 60 mm-diameter vessel. Determined parameters included densification energy (J), hardness (kN·mm−1), analytical densification energy (J), briquette volume (m3), bulk density of materials (kg·m−3), briquette bulk density (kg·m−3), and briquette volume energy (J·m−3). The ANOVA multivariate tests of significance results showed that for ground sunflower stalk briquettes, the force and particle size interactions had no significant effect (p > 0.05) on the above-mentioned parameters compared to the categorical factors, which had a significant effect (p < 0.05) similar to the effects of forces, moisture contents, and their interactions. For ground hazelnut husk briquettes, all the factors and their interactions had a significant effect on the determined parameters. These biomass materials could be attractive for the briquette market.
Analysis of the Impact of Building Integrated Photovoltaics (BIPV) on Reducing the Demand for Electricity and Heat in Buildings Located in Poland
Authors: Dobrzycki Arkadiusz , Kurz Dariusz , Mikulski Stanisław , Wodnicki Grzegorz
Published: May 2020

Based on a method to reduce energy consumption suggested in a real energy audit carried out in an industrial plant located in Poznań (city in Poland), the potential of using photovoltaic (PV) panels as wall cladding was analyzed, in order to reduce energy (electric and thermal) consumption and financial expenditure. The authors’ concept of using building integrated photovoltaic installation (BIPV) was presented and tested. This study checked whether the presence of PV modules would also affect heat transfer through the external wall of the building on which the installation is located. The analysis consisted of determining, for two variants, the heat transfer coefficients across the partition, in order to estimate the potential thermal energy savings. The first variant concerned the existing state, i.e., heat transfer through the external wall of the building, while the second included an additional partition layer in the form of photovoltaic panels. As a result, the use of panels as wall cladding allowed the improvement of the thermal parameters of the building wall (by increasing the thermal resistance of the wall), and the reduction of gas consumption for heating. The panels also generate electricity for the factory’s own needs. Payback time, compared to calculations which do not include changes in thermal parameters, was shortened from 14 to 11 years. The main reason for this is that gas consumption is reduced due to the improved heat transfer coefficient of the wall and the reduction of the heat loss of the facility. This aspect is usually overlooked when considering photovoltaic installations and, as argued by this paper, can be important.
Performance Investigation of a Two-Bed Type Adsorption Chiller with Various Adsorbents
Authors: Lee Jung-Gil , Bae Kyung Jin , Kwon Oh Kyung
Published: May 2020

In this study, the performance evaluation of an adsorption chiller (AD) system with three different adsorbents—silica-gel, aluminum fumarate, and FAM-Z01—was conducted to investigate the effects of adsorption isotherms and physical properties on the system’s performance. In addition, the performance evaluation of the AD system for a low inlet hot-water temperature of 60 °C was performed to estimate the performance of the system when operated by low quality waste heat or sustainable energy sources. For the simulation work, a two-bed type AD system is considered, and silica-gel, metal organic frameworks (MOFs), and ferro-aluminophosphate (FAPO, FAM-Z01) were employed as adsorbents. The simulation results were well matched with the laboratory-scale experimental results and the maximum coefficient of performance (COP) difference was 7%. The cooling capacity and COP of the AD system were investigated at different operating conditions to discuss the influences of the adsorbents on the system performance. Through this study, the excellence of the adsorbent, which has an S-shaped isotherm graph, was presented. In addition, the influences of the physical properties of the adsorbent were also discussed with reference to the system performance. Among the three different adsorbents employed in the AD system, the FAM-Z01 shows the best performance at inlet hot water temperature of 60 °C, which can be obtained from waste heat or sustainable energy, where the cooling capacity and COP were 5.13 kW and 0.47, respectively.
Measurements and Simulation Study of Daylight Availability and Its Impact on the Heating, Cooling and Lighting Energy Demand in an Educational Building
Authors: Rucińska Joanna , Trząski Adrian
Published: May 2020

This paper deals with the impact of the use of daylight on the overall energy demand for heating, cooling, and lighting in educational buildings. The energy performance of buildings is currently of the utmost importance as current European regulations, starting from 31st December 2020 impose that all new buildings must meet nearly zero-energy building requirements. This paper presents a study of the illuminance distribution in an educational room obtained from measurements and simulation results using two different models. One of the models, integrated with a thermal simulation software, was used to estimate the impact of daylight on the energy demand. The analysis included the use of various window types, lighting control system, reference point location, and daylight calculation model for a sample room in an educational building. Results of the analysis indicate that, due to the high share of lighting demand (reaching up to 78% of the primary energy balance), there is a need to take into account the efficiency of lighting systems during the design process to correctly determine the actual energy balance of a building, increase the quality of the design of lighting systems, as well as to select the optimal parameters of windows.
The Method of Image Singularities Employed for Oscillating Oblate Spheroids under a Free Surface
Authors: Anastasiou Eirini I. , Loukogeorgaki Eva , Chatjigeorgiou Ioannis K.
Published: May 2020

The main objective of this study is to develop a semi-analytical formulation for the radiation problem of a fully immersed spheroid in a liquid field of infinite depth. The term “spheroid” refers herein to the oblate geometry of arbitrary eccentricity and to the axisymmetric case, where the axis of symmetry is normal to the free surface. The proposed numerical approach is based on the method of image singularities, and it enables the accurate and fast calculation of the hydrodynamic coefficients for the translational degrees of freedom of the oblate spheroid. The excellent agreement of the results, with those of other investigators for the limiting case of the sphere and with those obtained using a respected boundary integral equation code, demonstrates the accuracy of the proposed methodology. Finally, extensive calculations are presented, illustrating the direct impact of the immersion depth and the slenderness of the spheroid on the hydrodynamic coefficients.
Characterization of Extra Early Spanish Clementine Varieties (Citrus clementina Hort ex Tan) as a Relevant Source of Bioactive Compounds with Antioxidant Activity
Authors: Cebadera Laura , Dias Maria Inês , Barros Lillian , Fernández-Ruiz Virginia , Cámara Rosa Mª , Del Pino Ángel , Santos-Buelga Celestino , Ferreira Isabel C.F.R. , Morales Patricia , Cámara Montaña
Published: May 2020

The most relevant nutrients and bioactive compounds (soluble sugars, dietary fiber, ascorbic acid and organic acids, individual phenolic compounds, fatty acids, and tocopherols) as well as antioxidant activity have been characterized in three extra early varieties of clementine (Citrus clementina Hort ex Tan. Basol, Clemensoon and Clemenrubí) cultivated in Valencia (Spain). Clementines are a relevant source of bioactive compounds, such as vitamin C (values around 80 mg/100 g), allowing to satisfy the recommended daily intake with the consumption of a normal portion. Sucrose was the most abundant sugar, and potassium the main mineral while manganese was the least. Fat content was very low (<0.5 mg/100 g), with palmitic acid and α-tocopherol the most abundant fatty acid and vitamin E form, respectively. Flavonoids were the predominant phenolic compounds, with narirutin/naringin and (neo)hesperidin the best represented ones. The antioxidant capacity evaluated by reducing power, DPPH, and β-carotene bleaching inhibition assays was satisfactory with values similar to those reported in other citrus fruits. Thus, this fruit is a relevant source of bioactive compounds with antioxidant properties of interest for consumers and the food industry.
Anti-Hypertensive Activity of Novel Peptides Identified from Olive Flounder (Paralichthys olivaceus) Surimi
Authors: Oh Jae-Young , Je Jun-Geon , Lee Hyo-Geun , Kim Eun-A , Kang Sang In , Lee Jung-Suck , Jeon You-Jin
Published: May 2020

There is a growing interest in the health benefits of functional foods. A benefit that has been long sought is the control of hypertension through dietary approaches. Hypertension has been implicated as a risk factor for cardiovascular disease and is therefore of clinical significance. Here, we aim to demonstrate the antihypertensive activity of novel peptides derived from surimi, a functional food ingredient made from refined fish myofibrillar proteins. Three peptides, Ile-Val-Asp-Arg (IVDR), Trp-Tyr-Lys (WYK), and Val-Ala-Ser-Val-Ile (VASVI), were isolated from surimi made from the olive flounder (Paralichthys olivaceus). Our results show that IVDR, WYK, and VASVI exhibited high Angiotensin I-converting Enzyme (ACE) inhibition activity. These peptides are also shown to increase phosphorylation of protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS), and significantly promote nitric oxide (NO) production in human umbilical vein endothelial cells. Oral administration of the peptides decreased blood pressure in spontaneously hypertensive rats (SHRs), thereby confirming that the peptides derived from surimi perform antihypertensive activity via the Akt/eNOS pathway. These results indicate that surimi made from P. olivaceus contains novel antihypertensive peptides that could be used to enhance the health benefits of food ingredients.
Quantitative Analysis of Spectinomycin and Lincomycin in Poultry Eggs by Accelerated Solvent Extraction Coupled with Gas Chromatography Tandem Mass Spectrometry
Authors: Wang Bo , Wang Yajuan , Xie Xing , Diao Zhixiang , Xie Kaizhou , Zhang Genxi , Zhang Tao , Dai Guojun
Published: May 2020

A method based on accelerated solvent extraction (ASE) coupled with gas chromatography tandem mass spectrometry (GC-MS/MS) was developed for the quantitative analysis of spectinomycin and lincomycin in poultry egg (whole egg, albumen and yolk) samples. In this work, the samples were extracted and purified using an ASE350 instrument and solid-phase extraction (SPE) cartridges, and the parameters of the ASE method were experimentally optimized. The appropriate SPE cartridges were selected, and the conditions for the derivatization reaction were optimized. After derivatization, the poultry egg (whole egg, albumen and yolk) samples were analyzed by GC-MS/MS. This study used blank poultry egg (whole egg, albumen and yolk) samples to evaluate the specificity, sensitivity, linearity, recovery and precision of the method. The linearity (5.6–2000 μg/kg for spectinomycin and 5.9–200 μg/kg for lincomycin), correlation coefficient (≥0.9991), recovery (80.0%–95.7%), precision (relative standard deviations, 1.0%–3.4%), limit of detection (2.3–4.3 μg/kg) and limit of quantification (5.6–9.5 μg/kg) of the method met the requirements for EU parameter verification. Compared with traditional liquid–liquid extraction methods, the proposed method is fast and consumes less reagents, and 24 samples can be processed at a time. Finally, the feasibility of the method was evaluated by testing real samples, and spectinomycin and lincomycin residues in poultry eggs were successfully detected.
Long-Term Outcomes in Stroke Patients with Cognitive Impairment: A Population-Based Study
Authors: Obaid Majed , Flach Clare , Marshall Iain , D. A. Wolfe Charles , Douiri Abdel
Published: May 2020

This study assesses five year outcomes of patients with cognitive deficits within the first three months after stroke. Population-based data from the South London Stroke Register between 1995 and 2018 were studied. Cognitive function was assessed using the Abbreviated-Mental-Test or Mini-Mental-State-Examination. Multivariable Poisson regression models with robust standard errors were constructed, to evaluate relative risks (RRs) and associations between post-stroke deterioration in cognitive function during the first three months on dependency, mortality, depression and institutionalisation. A total of 6504 patients with first-ever strokes were registered with a mean age of 73 (SD: 13.2). During the first three months post-stoke, approximately one-third of these stroke survivors either cognitively improved (37%), deteriorated (30%) or remained unchanged (33%). Post-stroke cognitive impairment was associated with increases, in five years, of the risks of mortality, dependency, depression and being institutionalised by RRs 30% (95% confidence interval: 1.1–1.5), 90% (1.3–2.6), 60% (1.1–2.4) and 50% (1.1–2.3), respectively. Deterioration in cognitive function by 10% or more between seven days and three months was associated with an approximate two-fold increased risk in mortality, dependency, and being institutionalised after one year, compared to stable cognitive function; RRs 80% (1.1–3.0), 70% (1.2–2.4) and two-fold (1.3–3.2), respectively. Monitoring further change to maintain cognitive abilities should be a focus to improve outcomes.
Fresh and Dry Weight Relations Are Predictors of Cycas micronesica Seed Age
Authors: Marler Thomas , Shaw Christopher
Published: May 2020

Cycas micronesica is a foundation species in several Micronesian islands and its seeds have been a historical source of starch for the island residents. The species has become endangered by invasive specialist insect herbivores and conservationists struggle with the inability to estimate the age of observed seeds. To inform this agenda, we evaluated numerous Cycas micronesica seed traits to determine if any exhibited a relationship with age and a substantial change in absolute value. Of the 30 direct and derived seed traits that we evaluated, most of them were non-linear and exhibited minimal change after about 12 months in age. The only traits that emerged as unambiguous estimators of age were the quotients derived as gametophyte fresh weight/total seed fresh weight and sarcotesta dry weight/sclerotesta dry weight. These two simple metrics can be used to accurately estimate seed age for this arborescent cycad species.
Assessment of Two Sweet Orange Cultivars Grafted on Selected Rootstocks Grown on an Inceptisol in Puerto Rico
Authors: Tirado-Corbalá Rebecca , Segarra-Carmona Alejandro , Matos-Rodríguez Manuel , Rivera-Ocasio Dania , Estévez de Jensen Consuelo , Pagán Jeniffer
Published: May 2020

Sweet oranges in Puerto Rico and other citrus-producing areas in the world have been greatly affected by the Huanglongbing disease (HLB). Historically, most of Puerto Rico’s citrus production has been located from 0–600 m above sea level, where fruit acquire a desirable color and flavor due to climatic conditions. However, higher populations of the disease vector Diaphorina citri Kuwayama have been reported at these elevations in Puerto Rico. Although only 6.4% of the land area is located above 600 m, it is composed mainly of environmentally sensitive or non-arable land where Inceptisols are the dominant soil order. For that reason, ‘Marr’s Early’ and ‘Pera’ sweet orange (Citrus sinensis) scions grafted on ‘Carrizo’, ‘HRS 802’, and ‘HRS 812’ rootstocks were planted in Alonso clay series Inceptisol (Oxic Humudepts) at 649 m in 2010. Tree growth parameters (height, diameter, canopy volume) and yield efficiency were measured. Fruit quality was determined from juice content (%), total soluble solids [°Brix], and pH. Leaf tissue analyses showed an optimum range for Ca, Mg, Na, P, B, Cu, and Zn, an indicator of tree health. A few were high (i.e., N and P) or in excess (i.e., Fe), but no clear connection to specific scions or rootstocks could be established. Tree height, tree diameter, fruit production, and juice content were higher in both sweet oranges grafted on ‘HRS 802’ compared with those on ‘HRS 812’ and ‘Carrizo’. Therefore, ‘HRS 802’ rootstock can be recommended to local farmers growing sweet oranges in Alonso series soil.
Open-Source Software Application for Hydrogeological Delineation of Potential Groundwater Recharge Zones in the Singida Semi-Arid, Fractured Aquifer, Central Tanzania
Authors: Mussa Kassim Ramadhani , Mjemah Ibrahimu Chikira , Machunda Revocatus Lazaro
Published: May 2020

This study attempted to delineate and map potential groundwater recharge zones of the Singida, semi-arid, fractured crystalline basement aquifer using open source remote sensing and GIS software. Various thematic maps such as lithology/hydrogeology, soil, land-cover/use, slope, lineament density, drainage density and rainfall distribution were integrated in QGIS software. Vector input layers were rasterized and resampled using QGIS wrap projection function to make sure that the grid cells are of the same size. Reclassification using SAGA and GRASS reclass algorithms in QGIS was carried out to realign the factor classes in a consistent scale, and reclassification to a scale of 1 to 5 was carried out to harmonize the results. The study identified a number of potential areas for groundwater recharge, groundwater exploration, groundwater development and potential areas for artificial groundwater recharge. Potential groundwater recharge zones for the Singida semi-arid fractured aquifer are restricted to areas with high lineament density, cultivated areas, grassland and flat to gentle slopes. The potential of groundwater recharge is also observed in areas with low drainage density. The delineated zones provide a good understanding of the potential recharge zones, which are a starting point for recharge zone protection. This blended approach can be utilized for carrying out suitability analysis using the weighted overlay analysis approach. Areas designated good and very good are recommended for artificial recharging structures as an alternative technique for enhancing groundwater recharge through rainwater harvesting. This will help to augment groundwater storage in this semi-arid environment.
Factors Related to Presenteeism among South Korean Workers Exposed to Workplace Psychological Adverse Social Behavior
Authors: Yi Jee-Seon , Kim Hyeoneui
Published: May 2020

Presenteeism negatively affects both individuals and society. This study identified factors of presenteeism among workers in South Korea, especially in relation to exposure to adverse social behaviors. Here, an adverse social behavior refers to any forms of workplace violence or intimidation. This study used the data from 23,164 full-time salaried employees, who participated in the fifth Korean Working Conditions Survey. This study attempted to predict presenteeism based on the exposure to adverse social behaviors and working conditions using logistic regression. Presenteeism was reported in 15.9% of the sample. Presenteeism was significantly higher among workers with the following characteristics: females, aged 40 years or older; middle school graduates; over 40 working hours a week; shift workers; no job-related safety information received; exposure to adverse social behavior and discrimination; and those with a high demand for quantitative work, low job autonomy, high emotional demands, and high job stress. The workers exposed to adverse social behavior showed a higher prevalence of presenteeism (41.2%), and low job autonomy was the most significant predictor of presenteeism. The findings of this study suggest that allowing enough autonomy in job-related roles may help alleviate presenteeism among those who have experienced adverse social behavior at work.
Statistical Modelling of the Effects of Weather Factors on Malaria Occurrence in Abuja, Nigeria
Authors: Segun Oguntade Emmanuel , Shohaimi Shamarina , Nallapan Meenakshii , Lamidi-Sarumoh Alaba Ajibola , Salari Nader
Published: May 2020

Background: despite the increase in malaria control and elimination efforts, weather patterns and ecological factors continue to serve as important drivers of malaria transmission dynamics. This study examined the statistical relationship between weather variables and malaria incidence in Abuja, Nigeria. Methodology/Principal Findings: monthly data on malaria incidence and weather variables were collected in Abuja from the year 2000 to 2013. The analysis of count outcomes was based on generalized linear models, while Pearson correlation analysis was undertaken at the bivariate level. The results showed more malaria incidence in the months with the highest rainfall recorded (June–August). Based on the negative binomial model, every unit increase in humidity corresponds to about 1.010 (95% confidence interval (CI), 1.005–1.015) times increase in malaria cases while the odds of having malaria decreases by 5.8% for every extra unit increase in temperature: 0.942 (95% CI, 0.928–0.956). At lag 1 month, there was a significant positive effect of rainfall on malaria incidence while at lag 4, temperature and humidity had significant influences. Conclusions: malaria remains a widespread infectious disease among the local subjects in the study area. Relative humidity was identified as one of the factors that influence a malaria epidemic at lag 0 while the biggest significant influence of temperature was observed at lag 4. Therefore, emphasis should be given to vector control activities and to create public health awareness on the proper usage of intervention measures such as indoor residual sprays to reduce the epidemic especially during peak periods with suitable weather conditions.