bluuebunny/crossref_metadata_2025 huggingface dataset:
Prospect Theory with Bounded Temporal Horizon for Modeling Prosumer Behavior in the Smart Grid
Authors: Rajabpour Mohsen , Yousefvand Mohammad , Mulligan Robert , Mandayam Narayan B.
Published: November 2021

We study prosumer decision-making in the smart grid in which a prosumer must decide whether to make a sale of solar energy units generated at her home every day or hold (store) the energy units in anticipation of a future sale at a better price. Specifically, we enhance a Prospect Theory (PT)-based behavioral model by taking into account bounded temporal horizons (a time window specified in terms of the number of days) that prosumers implicitly impose on their decision-making in arriving at “hold” or “sell” decisions of energy units. The new behavioral model for prosumers assumes that in addition to the framing and probability weighting effects imposed by classical PT, humans make decisions that will affect their lives within a bounded temporal horizon regardless of how far into the future their units may be sold. Modeling the utility of the prosumer with parameters such as the offered price on a day, the available energy units on a day, and the probabilities of the forecast prices, we fit the PT-based proposed behavioral model with bounded temporal horizons to prosumer data collected over 10 weeks from 57 homeowners who generated surplus units of solar power and had the opportunity to sell those units to the local utility at the price set that day by the utility or hold the units for sale in the future. For most participants, a model with a bounded temporal horizon in the range of 1–6 days provided a much better fit to their responses than was found for the traditional EUT-based model, thus validating the need to model PT effects (framing and probability weighting) and bounded temporal horizons imposed in prosumer decision-making.
Evaluating Consumers’ Adoption of Renewable Energy
Authors: Khalid Bilal , Urbański Mariusz , Kowalska-Sudyka Monika , Wysłocka Elżbieta , Piontek Barbara
Published: November 2021

The purpose of this study was to evaluate the consumers’ adoption of renewable energy in Poland. The study focused on finding out the factors that influence the adoption of the technology, considering its importance in conserving the environment. The study was conducted using a quantitative method, with primary data collected from 467 households using renewable energy technology in Poland. The research adopted the TAM model. The independent variables of the study included renewable energy initial cost, environmental concern, risk and trust for renewable energy, ease of use, financial incentives, and relative advantage. The dependent variable was renewable energy adoption. Structural equation modelling (SEM) was used to analyze the study hypotheses. The research found out that environmental concerns, ease of use, financial incentives, and relative advantage have a positive and significant influence on adoption of renewable energy technology in Poland. However, renewable energy initial cost and risk, and trust for renewable energy did not significantly influence renewable energy adoption. The study recommended that the stakeholders should consider the aspects of environmental concern as a key role player in pushing for adoption of renewable energy. The government, non-governmental organizations, and concerned stakeholders should consider giving incentives towards renewable energy adoption. Creating awareness regarding the benefits and strengths of renewable energy should be prioritized to the households.
Vision Analysis of the Influence of Piezoelectric Energy Harvesting on Vibration Damping of a Cantilever Beam
Authors: Grzybek Dariusz , Sioma Andrzej
Published: November 2021

A cantilever beam, manufactured from a steel-carrying substrate and two patches of Macro Fiber Composite of P2 type, was a subject of laboratory research. MFC patches were glued on both sides of the carrying substrate and were parallelly connected. An experimental determination of an optimal resistance for both energy harvesting and vibration passive damping of the cantilever beam was the purpose of the conducted laboratory research. The research contained 10 experiments in which courses of the energy-harvesting process and resistive passive damping of vibration were estimated. Energy harvesting was estimated by measurements of the generated current for the given load-resistance values. Resistive passive damping of vibration was assessed by using a vision method that enabled the displacements’ measurements of 10 selected points in the beam structure for the given shunt-resistance values. Values of both load resistance and shunt resistance were chosen on the basis of analytically calculated optimal load resistance and optimal shunt resistance. On the basis of the conducted experiments, the resistance range for which both the energy-harvesting process and the vibration-damping process are most effective was determined.
Feasibility Study on the Spread of NZEBs Using Economic Incentives
Authors: D’Agostino Diana , Esposito Milena , Minichiello Francesco , Renno Carlo
Published: November 2021

Nowadays, environmental and energy issues attract a lot of attention in the civil buildings sector, leading to the emergence of new technologies and new targets, which include Net Zero Energy Buildings (NZEBs). However, despite the great response in scientific research, the spread of NZEBs in Europe is quite limited. This is due not only to the lack of transposition of the related European Directives into the various national legislations, but also to the high initial cost of such high-performance buildings. The aim of this paper is to demonstrate how different energy retrofit strategies on existing buildings can lead to the achievement of the NZEB target if encouraged by tax incentives, at zero or almost zero cost. The introduction of tax incentives by individual EU member states would allow the spread of NZEBs that are still underdeveloped, especially in highly urbanized contexts. A suitable building energy dynamic simulation software has been used. The case study refers to a villa located in Southern Italy and for which different energy retrofit strategies are proposed to reach the NZEB target. For each case, an energy and economic evaluation is carried out to evaluate the feasibility of the interventions, exploiting the so-called “Super-Eco-Bonus 110%” incentive. The main results highlight that among the various solutions, the greatest energy cost reductions are obtained with the use of heat pump generators. Furthermore, the solution with the biomass boiler allows the use of a smaller number of photovoltaic panels to meet the yearly energy balance of the NZEB.
Experimental Study on the Stabilization Mechanism of Diffusion Flames in a Curved Impinging Spray Combustion Field in a Narrow Region
Authors: Kawahara Hideo , Furukawa Konosuke , Ogata Koichiro , Mitani Eiji , Mitani Koji
Published: November 2021

HVAF (High Velocity Air Flame) flame spraying can generate supersonic high-temperature gas jets, enabling thermal spraying at unprecedented speeds. However, there is a problem with the energy cost of this device. This study focused on combustors that used cheap liquid fuel (kerosene) as the fuel for HVAF. In this research, we have developed a compact combustor with a narrow channel as a heat source for the HVAF heat atomizer. Using this combustor, the stability of the flame formed in the combustor, the morphology of the flame, and the temperature behavior in the combustion chamber were investigated in detail. As a result, the magnitude of the swirling airflow had a great influence on the structure of the flame formed in the combustor, and the stable combustion range of the combustor could be determined. As the swirling air flow rate changes, the equivalent ratio of the entire combustor changes significantly, and the flame structure also transition from the premixed flame to the diffusion flame. From this study, it was confirmed that the temperature inside the combustor has great influence on the flame structure.
CFD Simulation of Hydrogen Generation and Methane Combustion Inside a Water Splitting Membrane Reactor
Authors: Zhao Te , Chen Chusheng , Ye Hong
Published: November 2021

Hydrogen production from water splitting remains difficult due to the low equilibrium constant (e.g., Kp ≈ 2 × 10−8 at 900 °C). The coupling of methane combustion with water splitting in an oxygen transport membrane reactor can shift the water splitting equilibrium toward dissociation by instantaneously removing O2 from the product, enabling the continuous process of water splitting and continuous generation of hydrogen, and the heat required for water splitting can be largely compensated for by methane combustion. In this work, a CFD simulation model for the coupled membrane reactor was developed and validated. The effects of the sweep gas flow rate, methane content and inlet temperature on the reactor performance were investigated. It was found that coupling of methane combustion with water splitting could significantly improve the hydrogen generation capacity of the membrane reactor. Under certain conditions, the average hydrogen yield with methane combustion could increase threefold compared to methods that used no coupling of combustion. The methane conversion decreases while the hydrogen yield increases with the increase in sweep gas flow rate or methane content. Excessive methane is required to ensure the hydrogen yield of the reactor. Increasing the inlet temperature can increase the membrane temperature, methane conversion, oxygen permeation rate and hydrogen yield.
Challenges for the Transition to Low-Temperature Heat in the UK: A Review
Authors: Reguis Antoine , Vand Behrang , Currie John
Published: November 2021

To reach net-zero emissions by 2050, buildings in the UK need to replace natural gas boilers with heat pumps and district heating. These technologies are efficient at reduced flow/return temperatures, typically 55/25 °C, while traditional heating systems are designed for 82/71 °C, and an oversized heating system can help this temperature transition. This paper reviews how heating systems have been sized over time in the UK and the degree of oversizing in existing buildings. It also reviews if lessons from other countries can be applied to the UK’s building stock. The results show that methods to size a heating system have not changed over time, but the modern level of comfort, the retrofit history of buildings and the use of margin lead to the heating system being generally oversized. It is not possible to identify a specific trend by age, use or archetype. Buildings in Scandinavia have a nascent readiness for low-temperature heat as they can use it for most of the year without retrofit. Limitations come primarily from the faults and malfunctions of such systems. In the UK, it is estimated that 10% of domestic buildings would be ready for a supply temperature of 55 °C during extreme external conditions and more buildings at part-load operation. Lessons from Scandinavia should be considered with caution. The building stock in the UK generally underperforms compared to other EU buildings, with heating systems in the UK operating at higher temperatures and with night set-back; the importance of providing a low-return temperature does not exist in the UK despite being beneficial for condensing boiler operation. Sweden and Denmark started to develop district heating technologies with limitations to supply temperatures some 40 years ago whereas the UK is only just starting to consider similar measures in 2021. Recommendations for policy makers in this context have been drawn from this review in the conclusions.
Hybrid Protection Scheme Based Optimal Overcurrent Relay Coordination Strategy for RE Integrated Power Distribution Grid
Authors: Shrivastava Aayush , Sharma Abhishek , Pandit Manjaree , Jately Vibhu , Azzopardi Brian
Published: November 2021

A directional overcurrent relay is commonly used to protect the power distribution networks of a distributed system. The selection of the appropriate settings for the relays is an important component of the protection strategies used to isolate the faulty parts of the system. The rapid growth of distributed generation (DG) systems present new challenges to these protection schemes. The effect of solar photovoltaic power plants on relay coordination is studied initially in this research work. A protection strategy was formulated to guarantee that the increased penetration of solar photovoltaic (PV) plants does not affect the relay coordination time. This paper addresses these issues associated with a high penetration of DG through the use of a hybrid protection scheme. The protection strategy is divided into two parts. The first part is based on an optimal fault current limiter value estimated with respect to constraints and the optimal time multiplier setting, and then the coordination time interval is estimated with respect to constraint in Part II. The results of these analyses show that a hybrid protection scheme can effectively handle the complexity of distributed generation (DG) and dynamic relay coordination problems. In this research, three optimization algorithms have been used for calculating the estimated value of impedance fault current limiter (Zfcl) and time multiplier setting (TMS). The response time of hybrid protection schemes is very important. If the computational time of their proposed algorithms is less than their actual computational time, then their response time to address the issue is also less. The performance in all algorithms was identified to arrive at a conclusion that the grey wolf optimized algorithm (GWO) algorithm can substantially reduce the computational time needed to implement hybrid protection algorithms. The GWO algorithm takes a computational time of 0.946 s, achieving its feasible solution in less than 1 s.
Design of a Low-Loss, Low-Cost Rolling Element Bearing System for a 5 kWh/100 kW Flywheel Energy Storage System
Authors: Haidl Peter , Buchroithner Armin
Published: November 2021

The bearings of a flywheel energy storage system (FESS) are critical machine elements, as they determine several important properties such as self-discharge, service life, maintenance intervals and most importantly cost. This paper describes the design of a low-cost, low-loss bearing system for a 5 kWh/100 kW FESS based on analytical, numerical and experimental methods. The special operating conditions of the FESS rotor (e.g., high rotational speeds, high rotor mass, vacuum) do not allow isolated consideration of the bearings alone, but require a systematic approach, taking into account aspects of rotor dynamics, thermal management, bearing loads and lubrication. The proposed design incorporates measures to mitigate both axial and radial bearing loads, by deploying resilient bearing seats and a lifting magnet for rotor weight compensation. As a consequence of minimized external loading, bearing kinematics also need to be considered during the design process. A generally valid, well-structured guideline for the design of such low-loss rolling bearing systems is presented and applied to the 5 kWh/100 kW FESS use case.
On the Wind Turbine Wake and Forest Terrain Interaction
Authors: Cheng Shyuan , Elgendi Mahmoud , Lu Fanghan , Chamorro Leonardo P.
Published: November 2021

Future wind power developments may be located in complex topographic and harsh environments; forests are one type of complex terrain that offers untapped potential for wind energy. A detailed analysis of the unsteady interaction between wind turbines and the distinct boundary layers from those terrains is necessary to ensure optimized design, operation, and life span of wind turbines and wind farms. Here, laboratory experiments were carried to explore the interaction between the wake of a horizontal-axis model wind turbine and the boundary layer flow over forest-like canopies and the modulation of forest density in the turbulent exchange. The case of the turbine in a canonical boundary layer is included for selected comparison. The experiments were performed in a wind tunnel fully covered with tree models of height H/zhub≈0.36, where zhub is the turbine hub height, which were placed in a staggered pattern sharing streamwise and transverse spacing of Δx/dc=1.3 and 2.7, where dc is the mean crown diameter of the trees. Particle image velocimetry is used to characterize the incoming flow and three fields of view in the turbine wake within x/dT∈(2,7) and covering the vertical extent of the wake. The results show a significant modulation of the forest-like canopies on the wake statistics relative to a case without forest canopies. Forest density did not induce dominant effects on the bulk features of the wake; however, a faster flow recovery, particularly in the intermediate wake, occurred with the case with less dense forest. Decomposition of the kinematic shear stress using a hyperbolic hole in the quadrant analysis reveals a substantial effect sufficiently away from the canopy top with sweep-dominated events that differentiate from ejection-dominated observed in canonical boundary layers. The comparatively high background turbulence induced by the forest reduced the modulation of the rotor in the wake; the quadrant fraction distribution in the intermediate wake exhibited similar features of the associated incoming flow.
Finite Element Analysis of Tidal Turbine Blade Subjected to Impact Loads from Sea Animals
Authors: Gavriilidis Ilias , Huang Yuner
Published: November 2021

The present work investigates structural response of tidal stream turbine blades subjected to impact loads from sea animals. A full-scale tidal turbine blade model was developed using a finite element modelling software ABAQUS, while a simplified geometry of an adult killer whale (Orcinus orca) was assumed in simulating impact on the blade. The foil profiles along the turbine blade were based on the NACA 63-8XX series, while the geometric and material properties of the sea animal were calibrated with experimental results. The numerical model simulated the dynamic response of the blade, accounting for radial velocities of the blade corresponding to real life scenarios. Different magnitudes and trajectories of the velocity vector of the sea animal were simulated, in order to investigate their influence on the turbine blade’s plastic deformation. Furthermore, multiple impacts were analysed, in order to monitor the accumulation of plastic strain in the material of the blade. Finally, the potential application of stainless steel material in tidal stream turbine blades for impact resistance was evaluated, through comparison of numerical results obtained from models using stainless steel and mild carbon steel materials.
Selection of Appropriate Dispatch Strategies for Effective Planning and Operation of a Microgrid
Authors: Shezan Sk. A. , Hasan Kazi Nazmul , Rahman Akhlaqur , Datta Manoj , Datta Ujjwal
Published: November 2021

The power system responsiveness may be improved by determining the ideal size of each component and performing a reliability analysis. This study evaluated the design and optimization of an islanded hybrid microgrid system with multiple dispatch algorithms. As the penetration of renewable power increases in microgrids, the importance and influence of efficient design and operation of islanded hybrid microgrids grow. The Kangaroo Island in South Australia served as the study’s test microgrid. The sizing of the Kangaroo Island hybrid microgrid system, which includes solar PV, wind, a diesel engine, and battery storage, was adjusted for four dispatch schemes. In this study, the following dispatch strategies were used: (i) load following, (ii) cycle charging, (iii) generator order, and (iv) combination dispatch. The CO2 emissions, net present cost (NPC), and energy cost of the islanded microgrid were all optimized (COE). The HOMER microgrid software platform was used to build all four dispatch algorithms, and DIgSILENT PowerFactory was used to analyze the power system’s responsiveness and dependability. The findings give a framework for estimating the generation mix and required resources for an islanded microgrid’s optimal functioning under various dispatch scenarios. According to the simulation results, load following is the optimum dispatch technique for an islanded hybrid microgrid that achieves the lowest cost of energy (COE) and net present cost (NPC).
Active Participation of Buildings in the Energy Networks: Dynamic/Operational Models and Control Challenges
Authors: Nikkhah Saman , Allahham Adib , Bialek Janusz W. , Walker Sara L. , Giaouris Damian , Papadopoulou Simira
Published: November 2021

New advances in small-scale generation and consumption technologies have shifted conventional buildings’ functionality towards energy-efficient active buildings (ABs). Such developments drew the attention of researchers all around the world, resulting in a variety of publications, including several review papers. This study conducts a systematic literature review so as to analyse the concepts/factors enabling active participation of buildings in the energy networks. To do so, a relatively large number of publications devoted to the subject are identified, introducing the taxonomy of control and optimisation methods for the ABs. Then, a study selection methodology is proposed to nominate potential literature that has investigated the role of ABs in the energy networks. The modelling approaches in enabling flexible ABs are identified, while the potential challenges have been highlighted. Furthermore, the citation network of included papers is illustrated by Gephi software and analysed using “ForceAtlas2” and “Yifan Hu Proportional” algorithms so as to analyse the insights and possibilities for future developments. The survey results provide a clear answer to the research question around the potential flexibility that can be offered by ABs to the energy grids, and highlights possible prospective research plans, serving as a guide to research and industry.
Single-Sided Microwave Near-Field Scanning of Pine Wood Lumber for Defect Detection
Authors: Radwan Mohamed , Thiel David V. , Espinosa Hugo G.
Published: November 2021

Defects and cracks in dried natural timber (relative permittivity 2–5) may cause structural weakness and enhanced warping in structural beams. For a pine wood beam (1200 mm × 70 mm × 70 mm), microwave reflection (S11) and transmission (S21) measurements using a cavity-backed slot antenna on the wood surface showed the variations caused by imperfections and defects in the wood. Reflection measurements at 4.4 GHz increased (>5 dB) above a major knot evident on the wood surface when the E-field was parallel to the wood grain. Similar results were observed for air cavities, independent of depth from the wood surface. The presence of a metal bolt in an air hole increased S11 by 2 dB. In comparison, transmission measurements (S21) were increased by 6 dB for a metal screw centered in the cavity. A kiln-dried pine wood sample was saturated with water to increase its moisture content from 17% to 138%. Both parallel and perpendicular E-field measurements showed a difference of more than 15 dB above an open saw-cut slot in the water-saturated beam. The insertion of a brass plate in the open slot created a 7 dB rise in the S11 measurement (p < 0.0003), while there was no significant variation for perpendicular orientation. By measuring the reflection coefficient, it was possible to detect the location of a crack through a change in its magnitude without a noticeable change (<0.01 GHz) in resonant frequency. These microwave measurements offer a simple, single-frequency non-destructive testing method of structural timber in situ, when one or more plane faces are accessible for direct antenna contact.
Analysing How Pre-Fire Habitat Legacy and Post-Fire Management Influence the Resilience of Reptiles to Fire
Authors: Muñoz Alberto , Felicísimo Ángel M. , Santos Xavier
Published: November 2021

At the landscape scale, the Mediterranean region is a mosaic of habitats occupied by plants and animals with different resilience to fire. One of these habitats, the pine plantation, is characterized by its structural simplification and susceptibility to fire. Despite its high flammability, few studies have compared the response of animal communities between pine plantations and other autochthonous woodlands. For five years after a large fire in southwestern Europe, we surveyed reptiles in two natural habitats (oak forest, scrubland) and a pine plantation managed with salvage logging, a post-fire practice which consists of the complete harvesting and removal of death burnt trees. Reptile abundance and species composition were examined to assess differences in the reptile community between these habitats. Differences between burnt and unburnt transects were limited to the first year after the fire, while, over the entire five-year period, differences in species composition and abundance were due to vegetation type instead of fire. The pine logged area showed a delay in the recovery of vegetation and also in the appearance of many reptile species after the fire. At the reptile species level, we found evidence of both positive responses to fire (for lizards with high heliothermic activity) and negative ones (for specialist snake species). Overall, our results confirm the resilience of the reptile community to fire. The mosaic of habitats in the Mediterranean region and the openness caused by fire can increase the reptile biodiversity (landscape- plus pyro-diversity effects), but some practices such as salvage logging coupled with fire regime shifts (larger and more frequent fires) can compromise the conservation of the biodiversity in fire-prone regions.
Timing of Drought Affected the Growth, Physiology, and Mortality of Mongolian Pine Saplings
Authors: Qian Hui , Dong Ai-Mei , Roitto Marja , Xiang Di-Ying , Zhang Gang , Repo Tapani , Wang Ai-Fang
Published: November 2021

Background and Objectives: More frequent and severe droughts are occurring due to climate change in northern China. In addition to intensity and duration, the timing of droughts may be decisive for its impacts on tree growth, mortality, and the whole forest ecosystem. The aim of this study was to compare the effect of drought occurring in the early- and mid-growing season on the growth and physiology of Mongolian pine (Pinus sylvestris var. mongolica Litv.) saplings. Materials and Methods: Four-year-old container saplings that were about to sprout were exposed to three treatments: (i) regular irrigation throughout the growing season (CTRL), (ii) no irrigation in the early growing season (weeks 1–5) followed by regular irrigation (EGD), (iii) no irrigation in the mid growing season (weeks 5–10), and regular irrigation in the early and late growing season (MGD). We measured the root and shoot growth, sapling mortality, and the physiological changes in the roots and needles periodically. Results: Drought in the mid growing season was more harmful than in the early growing season in terms of chlorophyll fluorescence, electrolyte leakage of needles, needle length, stem diameter increment, and sapling mortality. The high mortality in the mid growing season might be attributed to the joint effect of drought and high temperature. Drought in the early growing season decreased root growth, and the starch and soluble sugars in roots as much as the drought in the mid growing season. Abscisic acid concentration increased in fine roots, but decreased in old needles after drought. Conclusions: Special attention should be paid on forest sites susceptible to drought during afforestation in the face of ongoing climate change.
Regional Variation in Forest Canopy Height and Implications for Koala (Phascolarctos cinereus) Habitat Mapping and Forest Management
Authors: Mitchell Dave L. , Soto-Berelov Mariela , Jones Simon D.
Published: November 2021

Previous research has shown that the Koala (Phascolarctos cinereus) prefers larger trees, potentially making this a key factor influencing koala habitat quality. Generally, tree height is considered at regional scales which may overlook variation at patch or local scales. In this study, we aimed to derive a set of parameters to assist in classifying koala habitat in terms of tree height, which can then be used as an overlay for existing habitat maps. To determine canopy height variation within a specific forest community across a broad area in eastern Australia, we used freely available Airborne Laser Scanning (ALS) data and adopted a straightforward approach by extracting maximum-height ALS returns within a total of 288 30 m × 30 m “virtual” ALS plots. Our findings show that while maximum tree heights generally fall within published regional-scale parameters (mean height 33.2 m), they vary significantly between subregions (mean height 28.8–39.0 m), within subregions (e.g., mean height 21.3–29.4 m), and at local scales, the tree heights vary in response to previous land-use (mean height 28.0–34.2 m). A canopy height dataset useful for habitat management needs to recognise and incorporate these variations. To examine how this information might be synthesised into a usable map, we used a wall-to-wall canopy height map derived from ALS to investigate spatial and nonspatial clustering techniques that capture canopy height variability at both intra-subregional (100s of hectares) and local (60 hectare) scales. We found that nonspatial K-medians clustering with three or four height classes is suited to intra-subregional extents because it allows for simultaneous assessment and comparison of multiple forest community polygons. Spatially constrained clustering algorithms are suited to individual polygons, and we recommend the use of the Redcap algorithm because it delineates contiguous height classes recognisable on a map. For habitat management, an overlay combining these height classification approaches as separate attributes would provide the greatest utility at a range of scales. In addition to koala habitat management, canopy height maps could also assist in managing other fauna; identifying forest disturbance, regenerating forest, and old-growth forest; and identifying errors in existing forest maps.
Effect of Heavy Machine Traffic on Soil CO2 Concentration and Efflux in a Pinus koraiensis Thinning Stand
Authors: Kim Ikhyun , Han Sang-Kyun , Acuna Mauricio , Woo Heesung , Oh Jae-Heun , Choi Byoungkoo
Published: November 2021

Mechanized timber harvesting is cost efficient and highly productive. However, mechanized harvesting operations are often associated with several environmental problems, including soil compaction and disturbance. Soil compaction impedes air circulation between the soil and atmosphere, which in turn results in increased concentrations of CO2 within soil pores. In this study, we investigated the impact of forest machine traffic on soil conditions to determine soil CO2 efflux (Fc), and soil CO2 concentrations (Sc). Field measurements included soil bulk density (BD), soil temperature (ST), soil water content (SWC), Fc, and Sc over a 3-year period at a specific thinning operation site (Hwacheon-gun) in the Gangwon Province of Korea. To assess the soil impacts associated with machine traffic, we established four machine-treatment plots (MT) characterized by different geographical and traffic conditions. The results revealed that BD, Sc, and SWC increased significantly on the disturbed track areas (p < 0.05). Furthermore, reduced soil Fc values were measured on the soil-compacted (machine disturbed) tracks in comparison with undisturbed (control) areas. Variations in BD, SWC, and Sc were significantly different among the four MT plots. Additionally, in comparison with undisturbed areas, lower Fc and higher Sc values were obtained in compacted areas with high soil temperatures.
Wood Density and Ring Width in Quercus rotundifolia Trees in Southern Portugal
Authors: Sousa Vicelina , Silva Maria Emília , Louzada José Luís , Pereira Helena
Published: November 2021

Quercus rotundifolia Lam., known as holm oak or evergreen oak, occurs naturally in the western Mediterranean region, mainly as part of the agroforestry or agrosilvopastoral systems in Portugal (“montado”) and Spain (“dehesa”), and is economically important for acorn production. Less attention has been given to Q. rotundifolia wood, and its density variability is not known, namely related to tree growth. The wood density of 20 Q. rotundifolia trees was measured along the radial direction by X-ray densitometry and the factors responsible for ring width and wood density variation within and between trees were investigated at two sites located within the main species region in southern Portugal. Ring width was significantly different between sites, with an average of 1.81 mm and 1.55 mm. Wood density was very high and averaged between 888 kg/m3 and 914 kg/m3 but not significantly different between sites. Ring width and wood density showed a positive and significant correlation at both sites. Cambial age was the main source of variation for ring width and wood density, while between-tree effects accounted for a considerable proportion of wood density variation. The results are an important contribution for the species valorisation aiming at high-value wood products, also adding knowledge on the species growth of interest for tree selection and sustainable management.
Laws Governing Free and Actual Drying Shrinkage of 50 mm Thick Mongolian Scotch Pine Timber
Authors: Zhu Xiaodong , Zhao Jingyao , Gao Wanhui , Qian Cheng , Duan Yunjia , Niu Shuaichao , Cai Yingchun
Published: November 2021

The relationships between free shrinkage and actual shrinkage of different layers in Mongolian Scotch pine (Pinus sylvestris var. mongolica Litv.) were explored to provide basic data for the further study of drying shrinkage properties. The free shrinkage coefficients at different temperatures and the actual shrinkage strain of each layer were examined under conventional drying. The results showed high precision of free drying shrinkage of corresponding layers of thin small test strips in each layer of sawn timber. The free shrinkage increased linearly as moisture content declined. At the same temperature, the free shrinkage coefficient reached the largest values for the first layer (above 0.267%), while the smallest values were recorded for the ninth layer (below 0.249%). Except for the ninth layer, the free shrinkage coefficients in width directions of other representative layers decreased as temperature increased. At constant temperature, the difference in free shrinkage coefficient of test materials in the length direction of sawn timber was small for the first layer, but slightly larger and changed irregularly in the fifth and ninth layer direction. At the end of conventional drying, the plastic deformation of each layer in the early stage of drying showed a reducing trend or even reversal due to the effects of reverse stress and later damp heat. In sum, these findings look promising for future optimization of wood drying process.
The Size of the Assimilatory Apparatus and Its Relationship with Selected Taxation and Increment Traits in Pine (Pinus sylvestris L.) Stands
Authors: Beker Cezary , Turski Mieczysław , Kaźmierczak Katarzyna , Najgrakowski Tomasz , Jaszczak Roman , Rączka Grzegorz , Wajchman-Świtalska Sandra
Published: November 2021

Studies were carried for 200 trees coming from eight pure pine stands aged 25–95 years, growing in a fresh mixed coniferous forest habitat, in the Murowana Goślina Forest Experimental Station (52°34′ N, 17°00′ E) in western Poland. The aim of the study was to determine the size of the assimilatory apparatus of single pines (Pinus sylvestris L.): weight of leaved twigs (ugc), needle weight (ic), the volume of leaved twigs (ugo) and needle volume (io) and its relationship with selected dendrometric and increment traits of trees. The basic dendrometric traits were determined (height—h and diameter at breast height—d1.3) together with selected increments (heights—Ih5 and Ih10, diameter at breast height—Id5 and Id10, basal area at breast height—Ig5 and Ig10, volume—Iv5 and Iv10). A statistically significant linear correlation and a multiple linear correlation were shown between analysed traits, which confirms a strong relationship of the size of the assimilatory apparatus with tree increment. In this context, the strong correlation with the increment in basal area at breast height (correlation coefficient 0.8731 ÷ 0.9836) and with the increment in diameter at breast height (correlation coefficient 0.7835 ÷ 0.9581), after determining the increment in diameter at breast height requires only simple mathematical transformations to determine the increment in basal area at breast height. For the above-mentioned reasons, the increment in basal area at breast height is predisposed to be commonly used in the determination of the efficiency of the assimilatory apparatus of trees.
Indigenous Family Labor in Agroforestry Systems in the Context of Global Transformations: The Case of the Inga and Camëntsá Communities in Putumayo, Colombia
Authors: Palacios Bucheli Vandreé Julián , Cárcamo Mallen Robert Williams , Álvarez Macias Adolfo , Coral Claudia , Bokelmann Wolfgang
Published: November 2021

The Camëntsá and Inga indigenous communities still rely on agroforestry systems for their livelihood attainment, although globalization effects have also reached their settlements. Agroforestry systems, especially home gardens, are experiencing reduced size and species diversity and therefore gradually disappearing. This research aims to determine the indigenous family labor contribution to agroforestry systems as a strategy to secure their livelihoods. The methods include a census, household survey, interviews with key informants, and direct observation. Family labor contributes to reducing production costs in agroforestry systems. Three groups of households were identified from the cluster analysis to determine the family labor contribution: smaller, medium-sized, and larger farms. The smaller farms register better economic indicators compared to the other two groups. In addition, they show a positive cost–benefit ratio and profitability, which is explained by lower production costs compared to the gross income generated. Although larger farms have higher gross revenues, these households also assume higher production costs and incur higher input costs. Medium-sized farms face the worst scenario. There is a relationship between the use of family labor and the achievement of livelihoods related to economic indicators and biodiversity and the variety of species harvested on farms and used for self-consumption. Family labor helps to ensure local food security and generate income.
Aboveground Biomass of Living Trees Depends on Topographic Conditions and Tree Diversity in Temperate Montane Forests from the Slătioara-Rarău Area (Romania)
Authors: Duduman Gabriel , Barnoaiea Ionuț , Avăcăriței Daniel , Barbu Cătălina-Oana , Coșofreț Vasile-Cosmin , Dănilă Iulian-Constantin , Duduman Mihai-Leonard , Măciucă Anca , Drăgoi Marian
Published: November 2021

The study zone includes one of the largest montane old-growth forests in Europe (Slatioara UNESCO site), and understanding the structure and functioning of sill intact forests in Europe is essential for grounding management strategies for secondary forests. For this reason, we set out to analyze the dependencies between aboveground biomass (AgB), tree species and size diversity and terrain morphology, as well as the relationship between biomass and diversity, since neither of these issues have been sufficiently explored. We found that tree species diversity decreases with increased solar radiation and elevation. Tree size heterogeneity reaches its highest mean values at elevations between 1001 and 1100 m, on slopes between 50 and 60 degrees. AgB is differentiated with elevation; the highest mean AgB (293 tonnes per hectare) is recorded at elevations between 801 and 900 m, while it decreases to 79 tonnes per hectare at more than 1500 m a.s.l. It is also influenced by tree species diversity and tree size heterogeneity, with the highest AgB reached in the most complex forest ecosystems in terms of structural diversity. We showed that intact temperate montane forests develop maximum biomass for optimum species diversity and highest size heterogeneity; all three are modulated mainly by elevation.
Fungi from Galleries of the Emerald Ash Borer Produce Cankers in Ash Trees
Authors: Rajtar Nickolas N. , Held Benjamin W. , Blanchette Robert A.
Published: November 2021

The emerald ash borer (EAB, Agrilus planipennis) is a devastating invasive pest that has killed millions of ash trees in the United States and Canada. EAB was discovered in the US in 2002 and first reported in Minnesota in 2009. It attacks ash trees that are native to the United States, including Fraxinus americana (white ash), F. nigra (black ash) and F. pennsylvanica (green ash). It also attacks Chionanthus virginicus (white fringe tree). Seven species of fungi isolated and identified only from EAB-infested trees in a previous study as having the potential to cause cankers were used to test their pathogenicity in F. americana (white ash). The fungi used were Cytospora pruinosa, Diplodia mutila, Diplodia seriata, Paraconiothyrium brasiliense, Phaeoacremonium minimum, Phaeoacremonium scolyti, and Thyronectria aurigera. Two field experiments that used F. americana used two inoculation methods: woodchip and agar plug inoculations. Results indicated that all of the fungi tested caused cankers in varying amounts, as compared to the controls. The largest cankers were caused by D. mutila (270 mm2), C. pruinosa (169 mm2), and D. seriata (69 mm2). All fungi except for T. aurigera were re-isolated and sequenced to confirm Kochs’ postulates. Canker-causing fungi found in association with EAB galleries have the potential to contribute to tree dieback and mortality.
Helminths in Myomorph Rodents (Rodentia, Myomorpha) from the National Park “Smolny” and Its Surroundings (European Russia)
Authors: Kirillova Nadezhda , Ruchin Alexander , Kirillov Alexander
Published: November 2021

The National Park “Smolny” is a large forest area, located in the center of European Russia. The helminth fauna of myomorph rodents was studied for the first time within the National Park in 2018–2020. Rodents were examined by the method of complete helminthological dissection. A total of 30 species of parasites were recorded in 11 rodent species: 6 trematodes, 11 cestodes and 13 nematodes. The trematode Plagiorchis maculosus (Rudolphi, 1802) was found in Clethrionomys glareolus (Schreber, 1780) from the Russian fauna for the first time. Clethrionomys glareolus and Microtus arvalis (Pallas, 1779) are new hosts for P. maculosus and metacestode Versteria mustelae (Gmelin, 1790), respectively. The most widespread and eurybiont rodent species have the most diverse and rich helminth fauna, such as C/ glareolus (14 species), Apodemus agrarius (Pallas, 1771) (12) and Sylvaemus uralensis (Pallas, 1811) (10). The helminth fauna is less diverse in Sylvaemus flavicollis (Melchior, 1834), M. arvalis (7 species each), Microtus agrestis (Linnaeus, 1761) (5), Microtus subterraneus (de Selys-Longchamps, 1836) (3), Sicista betulina (Pallas, 1779) (2) and Arvicola amphibius (Linnaeus, 1758) (1). Comparative analysis the helminth fauna of small rodents from the National Park “Smolny” with micromammals from other regions of European Russia revealed that the high similarity with other areas reaches the helminth fauna of M. subterraneus, S. flavicollis, S. uralensis, S. betulina, A. amphibius and M. agrestis.
Towards Virtuous Cloud Data Storage Using Access Policy Hiding in Ciphertext Policy Attribute-Based Encryption
Authors: Mohd Satar Siti Dhalila , Hussin Masnida , Hanapi Zurina Mohd , Mohamed Mohamad Afendee
Published: November 2021

Managing and controlling access to the tremendous data in Cloud storage is very challenging. Due to various entities engaged in the Cloud environment, there is a high possibility of data tampering. Cloud encryption is being employed to control data access while securing Cloud data. The encrypted data are sent to Cloud storage with an access policy defined by the data owner. Only authorized users can decrypt the encrypted data. However, the access policy of the encrypted data is in readable form, which results in privacy leakage. To address this issue, we proposed a reinforcement hiding in access policy over Cloud storage by enhancing the Ciphertext Policy Attribute-based Encryption (CP-ABE) algorithm. Besides the encryption process, the reinforced CP-ABE used logical connective operations to hide the attribute value of data in the access policy. These attributes were converted into scrambled data along with a ciphertext form that provides a better unreadability feature. It means that a two-level concealed tactic is employed to secure data from any unauthorized access during a data transaction. Experimental results revealed that our reinforced CP-ABE had a low computational overhead and consumed low storage costs. Furthermore, a case study on security analysis shows that our approach is secure against a passive attack such as traffic analysis.
Configurable Hardware Core for IoT Object Detection
Authors: Miranda Pedro R. , Pestana Daniel , Lopes João D. , Duarte Rui Policarpo , Véstias Mário P. , Neto Horácio C. , de Sousa José T.
Published: November 2021

Object detection is an important task for many applications, like transportation, security, and medical applications. Many of these applications are needed on edge devices to make local decisions. Therefore, it is necessary to provide low-cost, fast solutions for object detection. This work proposes a configurable hardware core on a field-programmable gate array (FPGA) for object detection. The configurability of the core allows its deployment on target devices with diverse hardware resources. The object detection accelerator is based on YOLO, for its good accuracy at moderate computational complexity. The solution was applied to the design of a core to accelerate the Tiny-YOLOv3, based on a CNN developed for constrained environments. However, it can be applied to other YOLO versions. The core was integrated into a full system-on-chip solution and tested with the COCO dataset. It achieved a performance from 7 to 14 FPS in a low-cost ZYNQ7020 FPGA, depending on the quantization, with an accuracy reduction from 2.1 to 1.4 points of mAP50.
Improving Institutional Repositories through User-Centered Design: Indicators from a Focus Group
Authors: González-Pérez Laura Icela , Ramírez-Montoya María Soledad , García-Peñalvo Francisco José
Published: November 2021

User experience with intuitive and flexible digital platforms can be enjoyable and satisfying. A strategy to deliver such an experience is to place the users at the center of the design process and analyze their beliefs and perceptions to add appropriate platform features. This study conducted with focus groups as a qualitative method of data collection to investigate users’ preferences and develop a new landing page for institutional repositories with attractive functionalities based on their information-structural rules. The research question was: What are the motivations and experiences of users in an academic community when publishing scientific information in an institutional repository? The focus group technique used in this study had three sessions. Results showed that 50% of the participants did not know the functionalities of the institutional repository nor its benefits. Users’ perceptions of platforms such as ResearchGate or Google Scholar that provide academic production were also identified. The findings showed that motivating an academic community to use an institutional repository requires technological functions, user guidelines that identify what can or cannot be published in open access, and training programs for open access publication practices and institutional repository use. These measures align with global strategies to strengthen the digital identities of scientific communities and thus benefit open science.