bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation on Intermittent Operation Characteristics of Dual-Temperature Refrigeration System Using Hydrocarbon Mixture
Authors: Chen Qi , Li Yinsong
Published: May 2022

An experimental rig of a zeotropic mixture separation condensation-based dual-temperature refrigeration cycle is built and the mixture R290/R600a is used as the refrigerant. Compared with a conventional cycle, the proposed refrigeration system demonstrates its application advantages under an on–off operation mode. Furthermore, the on–off periodic operation behaviors of this refrigeration system are experimentally investigated. The influence of a different refrigerant charge, a refrigerant mass fraction, a throttling valve opening, and ambient temperature are explored to evaluate the cyclic operation characteristics. The results reveal that the compressor average power for the duration of the compressor startup increases and the compressor duty cycle first declines then increases with the rise of the refrigerant charge. The average compressor during an on-period decreases from 104.5 W to 79.2 W and meanwhile the compressor duty cycles fluctuates between 72.1% and 96.9% as the R600a-charged concentration increases from 30% to 70%. The average power of the compressor during the on-period and the duty cycle are also sensitive to the freezer valve opening variation. Thus, the minimum energy consumption of 1.60 kWh·24 h−1 is achieved at the refrigerant charge of 300 g, a R600a-charged mass fraction of 50%, and a freezer throttling valve opening of 10%. A higher ambient temperature deteriorates heat transfer during condensation and increases the cabinets’ heat load, the compressor duty cycle, and eventually affects the daily power consumption. Generally, the present study offers an in-depth insight of cyclic operation characteristics of a separation condensation-based hydrocarbon mixture dual-temperature refrigerator under two parallel evaporators’ concurrent cooling process.
Analysis of High-Frequency Common Mode Component Characteristics of Common Mode Peak Voltage Suppression Method for Indirect Matrix Converter
Authors: Liu Haiming , Huang Linfeng , Lin Cheng , Ding Yifu , Wang Yun , Li Shanhu
Published: May 2022

A variety of modulation strategies for suppressing output common-mode voltage (CMV) of indirect matrix converters (IMC) have been proposed, but most of them mainly reduce the peak of CMV by 42.3%. The frequency-domain characteristics of CMV have not been deeply analyzed. In order to improve the theory of frequency-domain characteristics of output common-mode voltage of IMC, this paper proposed a common-mode frequency domain analysis of five common-mode voltage peak suppression modulation methods for IMC. The common-mode voltage spectrum corresponding to the five modulation methods is obtained by the triple Fourier series, and the variation laws of the output common-mode components of the five modulation methods under different modulation indexes are compared and analyzed. By comparing and analyzing the low-frequency amplitude characteristics and high-frequency amplitude characteristics of five modulation methods, the suppression performance of the five modulation methods is evaluated. Finally, experiments verify the correctness of the theoretical analysis of the frequency domain characteristics of the output common-mode voltage of the indirect matrix converter.
Active Distribution Networks with Microgrid and Distributed Energy Resources Optimization Using Hierarchical Model
Authors: Blasi Thaís M. , de Aquino Cyntia C. C. B. , Pinto Rafael S. , de Lara Filho Mauro O. , Fernandes Thelma S. P. , Vila Clodomiro U. , Aoki Alexandre R. , dos Santos Rodrigo B. , Tabarro Fabricio H.
Published: May 2022

Distribution networks have undergone a series of changes, with the insertion of distributed energy resources, such as distributed generation, energy storage systems, and demand response, allowing the consumers to produce energy and have an active role in distribution systems. Thus, it is possible to form microgrids. From the active grid’s point of view, it is necessary to plan the operation considering the distributed resources and the microgrids connected to it, aiming to ensure the maintenance of grid economy and operational safety. So, this paper presents the proposition of a hierarchical model for planning the daily operation of active distribution grids with microgrids. In this case, the entire grid operation is optimized considering the results from the microgrid optimization itself. If none of the technical constraints, for example voltage levels, are reached, the grid is optimized, however, if there are some violations in the constraints feedback is sent to the internal microgrid optimization to be run again. Several scenarios are evaluated to verify the iteration among the controls in a coordinated way allowing the optimization of the operation of microgrids, as well as of the distribution network. A coordinated and hierarchical operation of active distribution networks with microgrids, specifically when they have distributed energy resources allocated and operated in an optimized way, results in a reduction in operating costs, losses, and greater flexibility and security of the whole system.
Numerical Assessment of a Tension-Leg Platform Wind Turbine in Intermediate Water Using the Smoothed Particle Hydrodynamics Method
Authors: Tagliafierro Bonaventura , Karimirad Madjid , Martínez-Estévez Iván , Domínguez José M. , Viccione Giacomo , Crespo Alejandro J. C.
Published: May 2022

The open-source code DualSPHysics, based on the Smoothed Particle Hydrodynamics method for solving fluid mechanics problems, defines a complete numerical environment for simulating the interaction of floating structures with ocean waves, and includes external libraries to simulate kinematic- and dynamic-type restrictions. In this work, a full validation of the SPH framework using experimental data available for an experimental test campaign on a 1:37-scale floating offshore wind turbine tension-leg platform (TLP) is presented. The first set of validation cases includes a surge decay test, to assess the quality of the fluid–solid interaction, and regular wave tests, which stimulate the mooring system to a large extent. During this phase, tendons (tension legs) that are simulated by MoorDyn+ are validated. Spectral comparison shows that the model is able to capture the surge and pitch dynamic amplification that occurs around the resonant fundamental mode of vibration. This work concludes with a numerical investigation that estimates the response of TLP under extreme events defined using multiple realizations of irregular sea states; the results suggest that the tendon loads are sensitive to the sea-state realization, providing maximum tendon peak forces in a range of ±10% about the mean. Furthermore, it is shown that the load pattern that forms from considering the relative position of the tendons to the incident wave direction leads to higher forces (≈20%).
A Novel Optimal Power Allocation Control System with High Convergence Rate for DC Microgrids Cluster
Authors: Zaery Mohamed , Wang Panbao , Wang Wei , Xu Dianguo
Published: May 2022

A novel, fully distributed controller with a rapid convergence rate is developed to ensure the optimal loading dispatch for interconnected DC MGs. It comprises local and global-control levels, handling the economic load allocations in a finite-time manner, for distinct MGs and cluster of MGs, respectively. The local-control layer guarantees MG’s economic operation by matching the incremental costs (ICs) of all DGs, respecting the power equilibrium among generations and demands, DGs’ generation limits, as well as the transmission line losses. Furthermore, the economic operation of battery energy sources is considered, in the optimization problem, to strengthen the overall reliability and maximize energy arbitrage. The global controller adjusts MGs’ voltage references to determine the optimal exchanged power, between MGs, for reducing the global total generation cost (TGC). A rigorous analysis is developed to confirm the stable convergence of the developed controller. Extensive simulation case studies demonstrate the superiority of the proposed control system.
Experimental Performance Investigation of an Original Rotating Solar Still Design under Realistic Meteorological Conditions
Authors: Alqurashi Faris , Nciri Rached , Alghamdi Abdulrahman , Ali Chaouki , Nasri Faouzi
Published: May 2022

This research article proposes a novel design of solar still; furthermore, it investigates, experimentally, its thermal and productivity performances, as well as its efficiency, under the realistic meteorological conditions of the city of Gafsa, Tunisia (34.4311° N, 8.7757° E), in terms of ambient temperature and solar irradiance. The novel proposed design presents a cylindrical solar still with a rotating transparent plastic (Plexiglass) cover, wiped continuously on the inner surface. A specific technological configuration of the evaporation and condensation compartments is elaborated. A real prototype is manufactured in order to carry out the performance experimental investigation. A performance comparison is carried out between the cylindrical transparent plastic cover rotating and it being fixed, for two experimentation days presenting slightly different meteorological conditions. The experimental water and plastic cover temperatures, the hourly and the cumulative water production, as well as the hourly efficiency are deeply quantified and interpreted.
Study on the Influence of Characteristics of Pore Structure on Adsorption Capacity of Tectonic Coals in Guizhou Province
Authors: Sui Hao , Li Xijian , Pei Peng
Published: May 2022

The occurrence and migration of coalbed methane (CBM) is inseparably associated with the pore structure within the coal seams. Three Permian Longtan Formation tectonic coal samples (QL, XL, XT) from Guizhou Province were studied to determine pore size distribution and characteristics, as well as factors that influence adsorption. Adsorption test results show that all samples generally have “ink bottle”-type pores, with large pore capacity but poor connectivity. Furthermore, the fractal dimension Df, the tortuosity “τ”, and tortuous fractal dimension DT of samples were calculated. Among the studied tectonic coals, moisture, ash, tortuosity, and volatile fraction have a positive effect on the maximum adsorption capacity (VL), whereas intact coals’ tortuosity volatile has a negative correlation with the maximum adsorption capacity (VL).
Simulation of Water Influx and Gasified Gas Transport during Underground Coal Gasification with Controlled Retracting Injection Point Technology
Authors: Chen Yanpeng , Wang Tianduoyi , Zhang Jinhua , Zhang Mengyuan , Xue Junjie , Shi Juntai , Kang Yongshang , Li Shengjie
Published: May 2022

Underground coal gasification (UCG) may change the energy consumption structure from coal-dominated to gas-dominated in the years to come. Before that, three important problems need to be solved, including failure of gasification due to large amounts of water pouring into the gasifier, environmental pollution caused by gas migration to the surface, and low calorific value caused by poor control of the degree of gasification. In this study, a geological model is first established using the computer modeling group (CMG), a commercial software package for reservoir simulation. Then, the inflow of coal seam water into the gasifier during the controlled retracting injection point (CRIP) gasification process is simulated based on the geological model, and the maximum instantaneous water inflow is simulated too. Meanwhile, the migration of gasified gas is also simulated, and the migration discipline of different gases is shown. Finally, the pressure distributions in two stages are presented, pointing out the dynamic pressure characteristics during the UCG process. The results show that (a) the cavity width, production pressure, and gasifier pressure are negatively correlated with the maximum instantaneous water inflow, while the initial formation pressure, injection pressure, coal seam floor aquifer energy, and temperature are positively correlated; (b) CO2 is mainly concentrated near the production well and largely does not migrate upward, O2 migrates upward slowly, while CH4, CO and H2 migrate relatively quickly. When the injection–production pressure difference is 2 MPa, it takes 33.5 years, 40 years, and 44.6 years for CH4, CO, and H2 to migrate from a depth of 1000 m to 200 m, respectively. When the pressure difference increases to 4 MPa, the gas migration rate increases about two-fold. The aquifer (3 MPa) above a coal outcrop can slow down the upward migration rate of gas by 0.03 m/day; (c) the pressure near the production well changes more significantly than the pressure near the injection well. The overall gasifier pressure rises with gasifier width increases, and the pressure distribution always presents an asymmetric unimodal distribution during the receding process of the gas injection point. The simulation work can provide a theoretical basis for the operation parameters design and monitoring of the well deployment, ensuring the safety and reliability of on-site gasification.
40 W Continuous Wave Ce:Nd:YAG Solar Laser through a Fused Silica Light Guide
Authors: Almeida Joana , Liang Dawei , Garcia Dário , Tibúrcio Bruno D. , Costa Hugo , Catela Miguel , Guillot Emmanuel , Vistas Cláudia R.
Published: May 2022

The solar laser power scaling potential of a side-pumped Ce:Nd:YAG solar laser through a rectangular fused silica light guide was investigated by using a 2 m diameter parabolic concentrator. The laser head was formed by the light guide and a V-shaped pump cavity to efficiently couple and redistribute the concentrated solar radiation from the parabolic mirror to a 4 mm diameter, 35 mm length Ce(0.1 at.%):Nd(1.1 at.%):YAG laser rod. The rectangular light guide ensured a homogeneous distribution of the solar radiation along the laser rod, allowing it to withstand highly concentrated solar energy. With the full collection area of the parabolic mirror, the maximum continuous wave (cw) solar laser power of 40 W was measured. This, to the best of our knowledge, corresponds to the highest cw laser power obtained from a Ce:Nd:YAG medium pumped by solar radiation, representing an enhancement of two times over that of the previous side-pumped Ce:Nd:YAG solar laser and 1.19 times over the highest Cr:Nd:YAG solar laser power with a rectangular light-guide. This research proved that, with an appropriate pumping configuration, the Ce:Nd:YAG medium is very promising for scaling solar laser output power to a higher level.
Development and Comparison of Thermodynamic Equilibrium and Kinetic Approaches for Biomass Pyrolysis Modeling
Authors: Safarian Sahar , Rydén Magnus , Janssen Matty
Published: May 2022

Biomass pyrolysis is considered as a thermochemical conversion system that is performed under oxygen-depleted conditions. A large body of literature exists in which thermodynamic equilibrium (TE) and kinetic approaches have been applied to predict pyrolysis products. However, the reliability, accuracy and predictive power of both modeling approaches is an area of concern. To address these concerns, in this paper, two new simulation models based on the TE and kinetic approaches are developed using Aspen Plus, to analyze the performance of each approach. Subsequently, the results of two models are compared with modeling and experimental results available in the literature. The comparison shows that, on the one hand, the performance of the TE approach is not satisfactory and cannot be used as an effective way for pyrolysis modeling. On the other hand, the results generated by the new model based on the kinetic approach suggests that this approach is suitable for modeling biomass pyrolysis processes. Calculation of the root mean square error (RMS), to quantify the deviation of the model results from the experiment results, confirms that this kinetic model presents superior agreement with experimental data in comparison with other kinetic models in the literature. The acquired RMS for the developed kinetic method in this paper varies within the span of 1.2 to 3.2 depending on temperature (400–600 °C) and various feedstocks (pine spruce sawdust, bagasse, wood bark, beech wood and paddy straw).
A Production and Delivery Model of Hydrogen from Solar Thermal Energy in the United Arab Emirates
Authors: Joubi Abdulrahman , Akimoto Yutaro , Okajima Keiichi
Published: May 2022

Hydrogen production from surplus solar electricity as energy storage for export purposes can push towards large-scale application of solar energy in the United Arab Emirates and the Middle East region; this region’s properties of high solar irradiance and vast empty lands provide a good fit for solar technologies such as concentrated solar power and photovoltaics. However, a thorough comparison between the two solar technologies, as well as investigating the infrastructure of the United Arab Emirates for a well-to-ship hydrogen pathway, is yet to be fully carried out. Therefore, in this study we aim to provide a full model for solar hydrogen production and delivery by evaluating the potential of concentrated solar power and photovoltaics in the UAE, then comparing two different pathways for hydrogen delivery based on the location of hydrogen production sites. A Solid Oxide Cell Electrolyzer (SOEC) is used for technical comparison, while the shortest routes for hydrogen transport were analyzed using Geographical Information System (GIS). The results show that CSP technology coupled with SOEC is the most favorable pathway for large-scale hydrogen from solar energy production in the UAE for export purposes. Although PV has a slightly higher electricity potential compared to CSP, around 42 GWh/km2 to 41.1 GWh/km2, respectively, CSP show the highest productions rates of over 6 megatons of hydrogen when the electrolyzer is placed at the same site as the CSP plant, while PV generates 5.15 megatons when hydrogen is produced at the same site with PV plants; meanwhile, hydrogen from PV and CSP shows similar levels of 4.8 and 4.6 megatons of hydrogen, respectively, when electrolyzers are placed at port sites. Even considering the constraints in the UAE’s infrastructure and suggesting new shorter electrical transmission lines that could save up to 0.1 megatons of hydrogen in the second pathway, production at the same site with CSP is still the most advantageous scenario.
Comparative Research on Ventilation Characteristics of Scattering and Sample Room from Chinese Spallation Neutron Source
Authors: Wei Shengqiang , Lu Yiping , Yang Wei , Ke Yubin , Zheng Haibiao , Zhu Lingbo , Tong Jianfei , Mei Longwei , Fu Shinian , Yao Congju
Published: May 2022

Ventilation design of the scattering room and sample room in the Chinese Spallation Neutron Source (CSNS) is of great significance to maintain good indoor air quality and ensure the health of radiation workers. Based on the computational fluid dynamics (CFD) theory, the three-dimensional models of the scattering and sample rooms were established and fourteen layout schemes were simulated. Subsequently, the best schemes were selected among three typical layout schemes. On this basis, the paper presents research about the influence of changing the height of the outlet on the ventilation quality. The results show that the trend of numerical simulation is consistent with experimental data, which verifies the reliability of the numerical method. The change of the exhaust port position has an apparent influence on indoor ventilation, which reduces the air age by 4–27%. When the position of the outlet descends 0.5 m, the air age decreases by 2–11%, and this study provides guidance and suggestions for the design of the scattering and sample rooms.
Experimental and Theoretical Study of Surge Behavior in a Boil-Off Gas Centrifugal Compressor on an LNG Carrier
Authors: Lee Jinkwang , Cheon Yujin , Choi Younseok
Published: May 2022

In this study, we conducted experiments and numerical analysis on a 270 kW industrial-scale centrifugal compressor used in the fuel supply system of an LNG carrier in order to improve the lumped-parameter surge model by considering the viscosity in the pipeline and to confirm whether the improved model would be applicable. The steady and unsteady compressor performance curves were constructed using measurements and predictions, respectively. The flow through the pipeline was assumed to be both steady and unsteady, and each governing equation under the assumptions was derived in accordance with the lumped-parameter model. In the steady flow case, the surge behavior of the modified model was in a good agreement with the lumped-parameter model at surge parameter B = 4.8716. In the unsteady flow case, however, the modified model showed a deviation from the lumped-parameter model, and the simulation from the modified model described the surge behavior 5% more accurately than the lumped-parameter model. Through experiments and numerical analysis, this study showed that the present models are useful and applicable for describing the surge behavior of an industrial-scale single-stage centrifugal compressor.
Is There Spatial Dependence or Spatial Heterogeneity in the Distribution of Vegetation Greening and Browning in Southeastern China?
Authors: Chen Jin , Xu Chongmin , Lin Sen , Wu Zhilong , Qiu Rongzu , Hu Xisheng
Published: May 2022

Vegetation is an indispensable component of terrestrial ecosystems and plays an irreplaceable role in mitigation of climate change. Global vegetation changes (i.e., greening and browning) still occur frequently, however, little is known about the spatial relationships between these two processes. Based on the normalized difference vegetation index (NDVI) dataset from 1998 to 2018 in Fujian Province, China. The Theil-Sen and Mann-Kendall tests were used to explore temporal changes in vegetation growing, then the spatial relationships of greening and browning was distinguished with bivariate spatial autocorrelation analysis, and the spatial variation in the relationship between vegetation changes and driving factors was explored by the geographical detector. The results showed that from 1998 to 2018, the average NDVI value increased from 0.75 to 0.83; 89.61% of the study area experienced vegetation greening, while 5.7% experienced significant browning, with active vegetation changes occurred along roads and nearby cities. The spatial autocorrelation results showed that the spatial relationships between vegetation greening and browning were dominated by spatial heterogeneity (i.e., high greening and low browning, H-L clusters accounting for 60% and low greening and high browning, L-H clusters accounting for 14%), but we also revealed that there were still quite a few places (4%) with spatial dependence (i.e., high greening and browning, H-H clusters), occurring around urban areas and along roads. The factor detector indicated that the nighttime light intensity was among the most dominant factor of vegetation changes, followed by elevation and slope. Although the individual effect of the distance to roads was relatively weak on the vegetation changes, its indirect effect was found to be the strongest by the interaction detector, which was obtained from the interactions much larger than its independent impact. Simultaneously, the risk detector revealed that the greening preferred occurring in places with lower nighttime light intensity (<1.1 nW cm−2sr−1), higher elevation (>43.4 m) and slope (>6.3°). Moreover, we found that the vegetation changes primarily occurred within a distance of 1685.4 m from roads. Our findings could deepen the understanding of vegetation change patterns and provide advice for mitigating the impact on the vegetation changes.
Unraveling Visiting-Activity Patterns of Heterogeneous Communities for Urban-Park Planning and Design
Authors: Hui Ling-Chui , Jim Chi-Yung
Published: May 2022

Urban parks provide essential outdoor recreation space, especially for high-density cities. This study evaluated the park-visiting activity profiles of residents to inform the planning and design of community-relevant parks. The visiting and activity patterns of 465 Hong Kong adult residents were collected using a structured questionnaire. The correlations of visiting and activity patterns of the different socio-demographic groups were analyzed. Varying features of visiting and activity patterns were observed for different socio-demographic groups. Older patrons visited parks intensively for nature-enjoyment activities and had shorter travel if intended for social and physical-exercise activities. The middle-aged respondents with children mainly conducted family based recreation, visited parks more frequently, and traveled farther. The young adults reported lower patronage, but the visit frequency increased with the engagement level in outdoor and physical-exercise activities. The homemakers reported a high visit frequency and enthusiastic participation in social activities. They tended to visit more frequently and stay longer in parks for physical-exercise activities. Our study revealed the urban parks’ divergent patronage behavior and unique roles to disparate user groups. They furnished evidence to apply continually precision park planning, design, and promotion to achieve socially responsive and age-friendly parks.
Drainage Ditch Cleaning Has No Impact on the Carbon and Greenhouse Gas Balances in a Recent Forest Clear-Cut in Boreal Sweden
Authors: Tong Cheuk Hei Marcus , Nilsson Mats B. , Drott Andreas , Peichl Matthias
Published: May 2022

Ditch cleaning (DC) is increasingly applied to facilitate forest regeneration following clear-cutting in Fennoscandinavia. However, its impact on the ecosystem carbon and greenhouse gas (GHG) balances is poorly understood. We conducted chamber measurements to assess the initial DC effects on carbon dioxide (CO2) and methane (CH4) fluxes in a recent forest clear-cut on wet mineral soil in boreal Sweden. Measurements were conducted in two adjacent areas over two pre-treatments (2018/19) and two years (2020/21) after conducting DC in one area. We further assessed the spatial variation of fluxes at three distances (4, 20, 40 m) from ditches. We found that DC lowered the water table level by 12 ± 2 cm (mean ± standard error) and topsoil moisture by 0.12 ± 0.01 m3 m−3. DC had a limited initial effect on the net CO2 exchange and its component fluxes. CH4 emissions were low during the dry pre-treatment years but increased particularly in the control area during the wet years of 2020/21. Distance to ditch had no consistent effects on CO2 and CH4 fluxes. Model extrapolations suggest that annual carbon emissions decreased over the four years from 6.7 ± 1.4 to 1.6 ± 1.6 t-C ha−1 year−1, without treatment differences. Annual CH4 emissions contributed <2.5% to the carbon balance but constituted 39% of the GHG balance in the control area during 2021. Overall, our study suggests that DC modified the internal carbon cycling but without significant impact on the carbon and GHG balances.
Trembling Aspen Stand Response 15 Years after Windthrow, Salvage Harvesting, and Forest Renewal
Authors: Man Rongzhou , Rice Mya
Published: May 2022

Windthrow is a common occurrence in boreal forests, affecting wood supply and presenting regeneration challenges for forest managers. Salvage harvesting is often conducted afterwards to extract valuable wood and improve access for forest renewal activities. Research efforts, however, are generally limited to the effects of windthrow and salvage harvesting in the first few years following disturbance. In 2006, a catastrophic wind event occurred in a trembling aspen (Populus tremuloides Michx.) forest in northeastern Ontario. A field study was established with a range of silvicultural treatments from leaving after windthrow (W) to forest renewal treatments including windrow site preparation, planting, and herbicide release (WSPR). While the results of first 5-year assessment have been reported, the objective of the current study was to reassess treatment effects at 15 years post-disturbance, a stage of stand development that is more indicative of future forest conditions. Compared to the results of the earlier assessment, the 15-year assessment indicated that standing dead wood (snags) declined, whereas coarse downed wood did not change substantially over time. Post-disturbance salvage harvesting improved aspen regeneration in terms of density, stocking, and growth, but substantially reduced the proportion of conifers relative to windthrow only. Thus, salvage harvesting helped to sustain aspen composition, compared to other treatment options that increased proportions of pine and spruce trees from W to windthrow and salvage harvesting combined with windrow site preparation and planting (WSP), and from WSP to WSPR.
Potential of Using Natural and Synthetic Binder in Wood Composites
Authors: Liew Kangchiang , Tan Yufeng , Albert Charles Michael , Raman Vinodini , Boyou Michelle
Published: May 2022

The physical and mechanical properties of particleboard bonded with different cooking percentages of seaweed (Kappaphycus alvarezii), with different percentages of starch and different percentages of adhesives, and wood plastic composite (WPC) from High-Density Polyethlene (HDPE) with Acacia mangium wood powder were determined in this study. Seaweed mixed with different percentages of sulfuric acid (30%, 50%, 70%) and Sodium Hydroxide (70%, 50%, 30%) were prepared as a binder for particleboard. For a starch-based binder, different percentages of starch (10%, 15%, 20%) were prepared, before producing particleboard with different amounts of binder (20%, 25%, 30%). As for WPC, wood powders were bonded with different percentages of HDPE content (70%, 80%, 90%). Results indicated that WPC at 90% HDPE shows the best performance in the water absorption (0.07%) and thickness swelling test (2.54%). Starch-based particleboard recorded the highest Modulus of Elasticity (MOE) value (1115.07 N/mm2 at 15% starch with 30% amount of binder), while WPC (90% HDPE) and starch-based particleboard (10% starch with 20% amount of binder) both recorded the highest Modulus of Rupture (MOR) at the same value, which is 7.84 N/mm2. Starch-based particleboard has a better internal bond, which is 0.05 N/mm2. However, seaweed-based particleboard has a higher density value, which is 0.6 g/cm3.
Differential Responses of Soil Extracellular Enzyme Activity and Stoichiometric Ratios under Different Slope Aspects and Slope Positions in Larix olgensis Plantations
Authors: Wang Mingwei , Ji Li , Shen Fangyuan , Meng Jun , Wang Junlu , Shan Chengfeng , Yang Lixue
Published: May 2022

Soil enzymes play an important role in nutrient biogeochemical cycling in terrestrial ecosystems. Previous studies have emphasized the variability of soil enzyme activities and stoichiometric ratios in forest ecosystems in northern China. However, much less is known about soil enzyme activity, enzymatic stoichiometry ratios and microbial nutrient limitations in Larix olgensis plantations under different microsites. In this study, four specific extracellular enzyme activities (β-glucosidase, β-1,4-N-acetylglucosaminidase, L-leucine aminopeptidase, Acid phosphatase), and soil physicochemical properties were measured in the 0–20 cm soil layer. The results showed that slope aspect and slope position had a significant effect on soil moisture, soil bulk density, soil porosity, soil organic matter, ammonium nitrogen and nitrate-nitrogen. Meanwhile, slope aspect and slope position had a significant effect on β-glucosidase, β-1,4-N-acetylglucosaminidase, L-leucine aminopeptidase and Acid phosphatase activities while the highest activity of β-glucosidase (or β-1,4-N-acetylglucosaminidase), L-leucine aminopeptidase, and Acid phosphatase was observed in the upper slope of the east, the upper slope of the south, and the upper slope of the north; soil porosity, pH and soil organic matter were the main factors affecting soil extracellular enzyme activities. The log-transformed ratios of soil C-, N-, and P-acquiring enzyme activities were 1.00:1.06:1.17, indicating that soil microbial growth in this region was limited by N and P. Therefore, these findings highlight that N and P inputs should be considered in the management of L. olgensis plantations to improve soil microbial enzyme activity, alleviating N and P limitations.
Key Strategies Underlying the Adaptation of Mongolian Scots Pine (Pinussylvestris var. mongolica) in Sandy Land under Climate Change: A Review
Authors: Dang Hongzhong , Han Hui , Zhang Xueli , Chen Shuai , Li Mingyang , Liu Chunying
Published: May 2022

Forest degradation and mortality have been widely reported in the context of increasingly significant global climate change. As the country with the largest total tree plantation area globally, China has a great responsibility in forestry management to cope with climate change effectively. Mongolian Scots pine (Pinus sylvestris var. mongolica) was widely introduced from its natural sites in China into several other sandy land areas for establishing shelterbelt in the Three-North Shelter Forest Program, scoring outstanding achievements in terms of wind-breaking and sand-fixing. Mongolian Scots pine plantations in China cover a total area of ~800,000 hectares, with the eldest trees having >60 years. However, plantation trees have been affected by premature senescence in their middle-age stages (i.e., dieback, growth decline, and death) since the 1990s. This phenomenon has raised concerns about the suitability of Mongolian Scots pine to sandy habitats and the rationality for further afforestation, especially under the global climate change scenario. Fortunately, dieback has occurred only sporadically at specific sites and in certain years and has not spread to other regions in northern China; nevertheless, global climate change has become increasingly significant in that region. These observations reflect the strong drought resistance and adaptability of Mongolian Scots pines. In this review, we summarized the most recent findings on the ecohydrological attributes of Mongolian Scots pine during its adaptation to both fragile habitats and climate change. Five main species-specific strategies (i.e., opportunistic water absorb strategy, hydraulic failure risk avoidance strategy, water conservation strategy, functional traits adjustment strategy, rapid regeneration strategy) were summarized, providing deep insights into the tree–water relationship. Overall, the findings of this study can be applied to improve plantation management and better cope with climate-change-related drought stress.
Abandoned Fishpond Reversal to Mangrove Forest: Will the Carbon Storage Potential Match the Natural Stand 30 Years after Reforestation?
Authors: Mariano Habagat , Aguilos Maricar , Dagoc Frandel Louis , Sumalinab Bryan , Amparado Ruben
Published: May 2022

Mangroves are essential carbon reserves, and their role in carbon sequestration is remarkable. However, anthropogenic pressures such as aquaculture development threatened this highly susceptible ecosystem. Thus, the need to rehabilitate abandoned aquaculture ponds is a must to offset the ecological losses over the economic gains derived from these mangrove land-use changes. Thus, we chose a reforestation site of a once heavily utilized fishpond devastated by a tsunami in the late 1970s in Zamboanga del Sur, Philippines. We then established a similar study plot in a nearby natural mangrove forest as a point of reference. We determined the heterogeneity in vegetation and estimated the aboveground and soil carbon storage capacities. We also examined the distinct changes in species composition and zonation from the seaward towards the landward zones. About 30 years after the abandoned fishpond rehabilitation, we found the tree density of the Rhizopora mucronata Lamk. and Avicenia marina (Forsk.) Vierh-dominated reforestation site was higher (271 trees ha−1) compared to that of the Rhizophora apiculata Blume-dominated natural stand (211 trees ha−1) (p < 0.05). The total aboveground biomass at the natural mangrove forest was 202.02 Mg ha−1, which was close to that of the reforestation site (195.19 Mg ha−1) (p > 0.05). The total aboveground C in the natural mangrove forest was 90.52 Mg C ha−1, while that of the reforestation site was 87.84 Mg C ha−1 (p > 0.05). Surprisingly, the overall soil C content at the natural forest of 249.85 Mg C ha−1 was not significantly different from that of the reforestation site with 299.75 Mg C ha−1 (p > 0.05). There was an increasing soil C content trend as the soil got deeper from 0–100 cm (p < 0.05). The zonation patterns established across the landward to seaward zones did not affect the aboveground and soil carbon estimates (p > 0.05). Our study highlights the effectiveness of abandoned fishpond rehabilitation and calls for continuous restoration of the remaining abandoned aquaculture ponds in the country because of their ability to sequester and store carbon. Lastly, their potential to store huge amounts of carbon that will counterbalance anthropogenic CO2 emissions is likewise highlighted.
Vegetation Characteristics Based Climate Change Vulnerability Assessment of Temperate Forests of Western Himalaya
Authors: Pandey Rajiv , Sharma Jyoti , Singh Rajat , Rawat Monika , Saklani Himani , Tomar Pankaj Kumar , Tiwari Laxmikant , Bhatt Indra Dutt , Chand Tara , Bala Nirmalya , Panwar Vijender Pal , Semeraro Teodoro
Published: May 2022

Forests are under stress due to variety of climatic and non-climatic factors. Therefore for suitably managing the forests, vulnerability of the forests needs to be understood. The present paper attempts to estimate the vulnerability of various temperate forests of Western Himalaya due to climate change by analyzing the patterns of different taxonomical indices, based on primary data i.e., vegetation data. The paper presents a novel approach for climate change vulnerability assessment based on field data through a bottom-up approach. The vulnerability of the forests was assessed through the IPCC framework by suitably selecting indicators (taxonomy indices and climatic parameters) for the three dimensions of vulnerability i.e., exposure, sensitivity and adaptive capacity. The field data were collected from 17 different temperate forests distributed at the elevation “1600 to 3500 m” in Uttarakhand and Himachal Pradesh, India. Abundance and richness for each forest were collected by randomly laying ten quadrats of size 0.1 ha each. The analysis resulted into identifying the most and the least vulnerable temperate forests of the western Himalaya to climate change. The analysis showed that the Neoza Pine; Moist Deodar; Ban Oak and Dry Broadleaved and Coniferous forest were the most vulnerable forests in the Himalayan temperate forests due to climate change. Moreover, the variation in the levels of the vulnerability status of the selected forests was insignificant with elevational range as well as exposure to climate. The proposed method will serve for vulnerability estimation of forests due to climate change based on the actual realization of the species in the field.
Changes in the Microbiological Properties of Soils along the Gradient of the Altitude Zone of Mount Kivaka in Eastern Fennoscandia, Russia
Authors: Medvedeva Maria V. , Bakhmet Olga N.
Published: May 2022

This study was conducted on the territory of the national park Paanayarvi, located in the taiga zone of the European north. The altitude zone common in the territory of the national park is up to 350 m above sea level. The purpose of this work is to study the microbiological and biochemical properties of soils formed under conditions of a gradient of altitude zonation. This work was performed for the first time in this territory. Based on the fatty acid composition of the cell walls of microorganisms, the composition and structure of the microbial community were determined by chemato-mass spectrometry. The dominant microbocenosis of soils of undisturbed territories was revealed. Changes in prokaryotes and microscopic fungi in the gradient of the altitude zone occur in different directions, which is consistent with the work of other researchers. The results suggest that the formation of microbocenosis of soils located in different conditions of the phytocenotic environment depends on the location of the site relative to the height. The latter determines the flow of solar energy into the ecosystem and the hydrothermal regime of soils. The data obtained can be used in monitoring global climate changes, will become the basis for the formation of a general conceptual basis for the functioning of microbial communities of soils of low-mountain landscapes.
Development and Comparison of Seminested PCR, qPCR, and LAMP for the Rapid Detection of Arthrinium phaeospermum, the Causal Agent of Bamboo Blight
Authors: Zhang Han , Yang Weiyi , Xie Liling , Zhu Tianhui , Li Shuying , Han Shan , Lin Tiantian , Li Shujiang
Published: May 2022

Bambusa pervariabilis × Dendrocalamopsis grandis blight is a newly discovered disease in bamboos that has caused substantial economic loss to the affected areas. With the purpose of carrying out rapid detection of Bambusa pervariabilis × Dendrocalamopsis grandis blight caused by Arthrinium phaeospermum during the incubation period, three sets of detection assays were established: seminested PCR, real-time quantitative PCR, and LAMP. The specificity, sensitivity, and effectiveness of these assays were also detected. The results showed that the three assays were able to specifically amplify the target bands from five strains of Arthriniumphaeospermum from different sources, but none of the other 18 strains were able to obtain the specific bands. The sensitivity of the established seminested PCR, LAMP, and real-time quantitative PCR assays were 100, 10, and 1 pg/μL, respectively. The presence of A. phaeospermum could be detected in the early stage of disease using the total DNA of infected hybrid bamboo tissue as a template. The three systems established in this study are of great significance for the early diagnosis and rapid detection of hybrid bamboo blight.
Fermentation of Dairy-Relevant Sugars by Saccharomyces, Kluyveromyces, and Brettanomyces: An Exploratory Study with Implications for the Utilization of Acid Whey, Part II
Authors: Rivera Flores Viviana K. , DeMarsh Timothy A. , Gibney Patrick A. , Alcaine Samuel D.
Published: May 2022

In Greek-style yogurt production, every kilogram of product yields 2 to 3 kg of acid whey (YAW); this coproduct’s composition and low pH pose challenges for its proper valorization and reinsertion into the food supply chain. However, 240 mL of YAW contains over 9 g of lactose and represents a good source of minerals; these traits can be leveraged to develop nutritious fermented beverages. The purpose of this study is to investigate the aerobic fermentation of dairy sugars by different yeasts by characterizing these processes and their products. This will determine whether such methods provide viable options for the production of acetic-acid-containing beverages from YAW. To achieve this, yeast nitrogen base was used to prepare four growth media formulations, each supplemented with lactose, glucose, galactose, or a 1:1 mix of glucose and galactose (GLU:GAL), and each adjusted to a pH of 4.20. Fermentations were performed by pure cultures of S. cerevisiae, K. marxianus, B. claussenii, or B. bruxellensis, and were held at 25 °C with agitation at 185 rpm. For each treatment, density, pH, and microbial enumeration were measured over time to obtain process profiles, while ethanol, organic acids, and sugars were analyzed at the beginning and the end of each fermentation via HPLC, to determine resulting products. ANOVA and Tukey’s honest significant difference test at a significance level of 0.05 were used to compare residual sugars and fermentation products. Variable rates of sugar consumption were observed for each species. In GLU:GAL, B. claussenii consumed all of the glucose, left behind most of the galactose, and produced a high concentration of acetic acid. These results suggest the potential to develop versatile processes that target glucose for acetic acid production, while leaving available galactose to confer products with prebiotic properties. The development of processes for the conversion of YAW into beverages with organic acids and other healthful components not only aligns with consumers’ demands for better-for-you products, but also promotes the valorization of this otherwise underutilized dairy coproduct.
Coproduction of Microbial Oil and Carotenoids within the Circular Bioeconomy Concept: A Sequential Solid-State and Submerged Fermentation Approach
Authors: Villegas-Méndez Miguel Ángel , Montañez Julio , Contreras-Esquivel Juan Carlos , Salmerón Iván , Koutinas Apostolis , Morales-Oyervides Lourdes
Published: May 2022

The main objective of integrative biorefinery platforms is to propose efficient green methodologies addressed to obtain high-value compounds with low emissions through biochemical conversions. This work first screened the capacity of various oleaginous yeast to cosynthesize high-value biomolecules such as lipids and carotenoids. Selected strains were evaluated for their ability to coproduce such biocompounds in the waste-based media of agro-food (brewer’s spent grain, pasta processing waste and bakery waste). Carbon and nitrogen source feedstock was obtained through enzymatic hydrolysis of the agro-food waste, where up to 80% of total sugar/starch conversion was obtained. Then, the profitability of the bioprocess for microbial oil (MO) and carotenoids production by Sporobolomyces roseus CFGU-S005 was estimated via simulation using SuperPro Designer®. Results showed the benefits of establishing optimum equipment scheduling by identifying bottlenecks to increase profitability. Sensitivity analysis demonstrated the impact of MO price and batch throughput on process economics. A profitable process was achieved with a MO batch throughput of 3.7 kg/batch (ROI 31%, payback time 3.13 years). The results revealed areas that require further improvement to achieve a sustainable and competitive process for the microbial production of carotenoids and lipids.
On End-to-End Intelligent Automation of 6G Networks
Authors: Moubayed Abdallah , Shami Abdallah , Al-Dulaimi Anwer
Published: May 2022

The digital transformation of businesses and services is currently in full force, opening the world to a new set of unique challenges and opportunities. In this context, 6G promises to be the set of technologies, architectures, and paradigms that will promote the digital transformation and enable growth and sustainability by offering the means to interact and control the digital and virtual worlds that are decoupled from their physical location. One of the main challenges facing 6G networks is “end-to-end network automation”. This is because such networks have to deal with more complex infrastructure and a diverse set of heterogeneous services and fragmented use cases. Accordingly, this paper aims at envisioning the role of different enabling technologies towards end-to-end intelligent automated 6G networks. To this end, this paper first reviews the literature focusing on the orchestration and automation of next-generation networks by discussing in detail the challenges facing efficient and fully automated 6G networks. This includes automating both the operational and functional elements for 6G networks. Additionally, this paper defines some of the key technologies that will play a vital role in addressing the research gaps and tackling the aforementioned challenges. More specifically, it outlines how advanced data-driven paradigms such as reinforcement learning and federated learning can be incorporated into 6G networks for more dynamic, efficient, effective, and intelligent network automation and orchestration.