bluuebunny/crossref_metadata_2025 huggingface dataset:
Heteroepitaxial Growth of GaP Photocathode by Hydride Vapor Phase Epitaxy for Water Splitting and CO2 Reduction
Authors: Strömberg Axel , Yuan Yanqi , Li Feng , Manavaimaran Balaji , Lourdudoss Sebastian , Zhang Peng , Sun Yanting
Published: November 2022

Heteroepitaxial Zn-doped p-GaP was grown on (001) GaAs, (001) Si and (111) Si substrates by hydride vapor phase epitaxy for solar-driven photoelectrochemical applications of hydrogen generation by water splitting and CO2 reduction. Growth of GaP on Si was realized through the implementation of a low-temperature buffer layer, and the morphology and crystalline quality were enhanced by optimizing the precursor flows and pre-heating ambient substrate. The p-GaP/GaAs and p-GaP/Si samples were processed to photoelectrodes with an amorphous TiO2 coating for CO2 reduction and a combination of TiO2 layer and mesoporous tungsten phosphide catalyst for water splitting. P-GaP/GaAs with suitable Zn-doping concentration exhibited photoelectrochemical performance comparable to homoepitaxial p-GaP/GaP for water splitting and CO2 reduction. Degradation of photocurrent in p-GaP/Si photoelectrodes is observed in PEC water splitting due to the high density of defects arising from heteroepitaxial growth.
Recent Progress of Hydrogenation and Hydrogenolysis Catalysts Derived from Layered Double Hydroxides
Authors: Wang Zhihui , Zhang Wei , Li Cuiqing , Zhang Chen
Published: November 2022

Layered double hydroxides (LDHs), also known as hydrotalcite-like compounds, are widely used in many fields due to their unique structural advantages. Based on LDHs, a wide range of metal catalysts could be synthesized with high metal dispersion, tunable acid-base properties, facile but flexible preparation methods, strong metal-support interaction, and thermal stability. Owing to these outstanding advantages, LDH-derived materials manifest great potential as catalysts, particularly in hydrogenation and hydrogenolysis reactions. More than 200 papers published in the past five years in this field clearly indicated the rapid development of these materials. In this respect, it is imperative and essential to provide a timely review to summarize the current progress and motivate greater research effort on hydrogenation and hydrogenolysis catalysts derived from LDHs. In this review, the applications of LDH-derived materials as heterogeneous catalysts in various hydrogenation and hydrogenolysis reactions were comprehensively discussed. Hydrogenation of unsaturated chemical bonds, hydrodeoxygenation of oxygenated compounds, hydrogenolysis of carbon–carbon bonds and hydrogenation of nitrites and nitriles were described. This review demonstrates the extraordinary potentials of LDH-derived catalysts in hydrogenation and hydrogenolysis reactions, and it is undoubted that LDH-derived catalysts will play an even more significant role in the foreseeable future.
Are There Associations between Seminal Plasma Advanced Oxidation Protein Products and Selected Redox-Associated Biochemical Parameters in Infertile Male Patients? A Preliminary Report
Authors: Janiszewska Ewa , Kokot Izabela , Kmieciak Agnieszka , Gilowska Iwona , Faundez Ricardo , Kratz Ewa Maria
Published: November 2022

Oxidative stress (OS) is one of the reasons for male infertility. Seminal plasma contains a multitude of enzymes and ions which influence OS and thus may affect male fertility. The aim of the study was to check for associations between seminal plasma advanced oxidation protein products (AOPP) concentrations and levels of selected biochemical parameters (total protein, iron, uric acid, magnesium, calcium) in infertile men, and establish whether they are associated with sperm disorders. Seminal plasma AOPP, as well as total protein, iron, uric acid, calcium, and magnesium concentrations, were determined for the following patient groups: normozoospermic (N; n = 33), teratozoospermic (T; n = 30), asthenoteratozoospermic (AT; n = 18), and oligoasthenoteratozoospermic (OAT; n = 28). AOPP concentrations were significantly higher in N and T groups in comparison to AT and OAT groups. Total protein concentrations were significantly lower in the T group in comparison to the AT and OAT groups, whereas iron concentrations significantly decreased in the OAT group in comparison to the T and N patients. AOPP differentiates AT patients from men with other sperm disorders. Our results suggest that asthenozoospermia may be connected with total protein levels. Insufficient iron levels may reflect a decrease in sperm count.
Computational Portable Microscopes for Point-of-Care-Test and Tele-Diagnosis
Authors: Bian Yinxu , Xing Tao , Jiao Kerong , Kong Qingqing , Wang Jiaxiong , Yang Xiaofei , Yang Shenmin , Jiang Yannan , Shen Renbing , Shen Hua , Kuang Cuifang
Published: November 2022

In bio-medical mobile workstations, e.g., the prevention of epidemic viruses/bacteria, outdoor field medical treatment and bio-chemical pollution monitoring, the conventional bench-top microscopic imaging equipment is limited. The comprehensive multi-mode (bright/dark field imaging, fluorescence excitation imaging, polarized light imaging, and differential interference microscopy imaging, etc.) biomedical microscopy imaging systems are generally large in size and expensive. They also require professional operation, which means high labor-cost, money-cost and time-cost. These characteristics prevent them from being applied in bio-medical mobile workstations. The bio-medical mobile workstations need microscopy systems which are inexpensive and able to handle fast, timely and large-scale deployment. The development of lightweight, low-cost and portable microscopic imaging devices can meet these demands. Presently, for the increasing needs of point-of-care-test and tele-diagnosis, high-performance computational portable microscopes are widely developed. Bluetooth modules, WLAN modules and 3G/4G/5G modules generally feature very small sizes and low prices. And industrial imaging lens, microscopy objective lens, and CMOS/CCD photoelectric image sensors are also available in small sizes and at low prices. Here we review and discuss these typical computational, portable and low-cost microscopes by refined specifications and schematics, from the aspect of optics, electronic, algorithms principle and typical bio-medical applications.
Evaluation of Tissue Ischemia/Reperfusion Injury in Lung Recipients Supported by Intraoperative Extracorporeal Membrane Oxygenation: A Single-Center Pilot Study
Authors: Calabrese Fiorella , Pezzuto Federica , Fortarezza Francesco , Lunardi Francesca , Faccioli Eleonora , Lorenzoni Giulia , Boscolo Annalisa , Sella Nicolò , Gregori Dario , Schiavon Marco , Navalesi Paolo , Dell’Amore Andrea , Rea Federico
Published: November 2022

Intraoperative veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) as intraoperative hemodynamic support during lung transplantation is becoming a standard practice due to promising clinical results. Nevertheless, studies on tissue/molecular pathways investigating ischemia/reperfusion injury are still lacking. Patients receiving a bilateral lung transplantation between January 2012 and December 2018 at the University Hospital of Padova were included in this retrospective single-center observational study. The present study aimed to investigate ischemia/reperfusion injury in 51 tissue specimens obtained from 13 recipients supported by intraoperative VA-ECMO and 38 who were not. Several tissue analyses, including apoptosis evaluation and inducible nitric oxide synthase expression, were performed on the biopsies at the time of transplantation. Lung samples from the ECMO group (both pre- and post-reperfusion) were comparable, or for some parameters better, than samples from the non-ECMO group. Leukocyte margination was significantly lower in the ECMO group than in the non-ECMO group. Primary graft dysfunction, mainly at 24 and 48 h, was correlated with the tissue injury score of the post-reperfusion biopsy. The interquartile ranges for all morphological parameters showed high grade variability between pre- and post-reperfusion in the non-ECMO group. These preliminary data support the use of intraoperative ECMO based on lower lung tissue ischemia/reperfusion injury. Larger case series are mandatory to confirm our findings.
Tapestry Thinking: An Interview with Dr. Nalini Nadkarni on an Unexpected Life in Science
Authors: Logan Alan C. , Nadkarni Nalini M.
Published: November 2022

In the ongoing series of Nova Interviews, Challenges Advisory Board member Alan C. Logan meets with thought leaders, scientists, scholars, healthcare professionals, artisans and visionaries concerned about health at the scales of persons, places, and the planet. In this interview, Dr. Nalini M. Nadkarni, of the University of Utah, responds to a set of questions posed by Nova for Challenges. For over forty years, Dr. Nadkarni has been studying the fragility and resiliency of rainforest ecosystems. During this time, Dr. Nadkarni has prioritized science communication with an emphasis on highlighting the interdisciplinary relevancy of research findings. Dr. Nadkarni has worked to promote an integrative way of thinking about the various branches of science and medicine, with an eye toward shifting public policy. Her research career has taken her where only a small minority of scientists have traveled—from remote cloud forests to segregated housing within prison facilities. Dr. Nadkarni successfully challenged the Mattel Corporation to update their globally-recognized toy, Barbie, with women in science in mind. Here, Dr. Nadkarni reflects on the early influences that shaped her career, updates Challenges on the latest directions of her work, and discusses the ways in which the canopy ecosystem can help us understand the complex interconnected challenges of our time.
Corrosion Behaviors of Fe-22Cr-16Mn-0.55N High-Nitrogen Austenitic Stainless Steel in 3.5% NaCl Solution
Authors: Xu Song , Gao Fengyin , Han Jianyang , Xiong Shangfeng , Duan Xinyu , Zha Fanglin , Yu Bing , Yang Lanlan , Qiao Yanxin , Zheng Zhibin , Chen Jian
Published: November 2022

In this study, the corrosion behavior of the high-nitrogen austenitic stainless steel (HNS) Fe-22Cr-16Mn-0.55N before and after solution treatment (ST) in 3.5% NaCl solution has been investigated. The effect of a solution temperature of 1100 °C and heat preservation for 30 min on the corrosion resistance and passive film protection of HNS steel was studied. Open-circuit potential, potentiodynamic polarization and electrochemical impedance tests were used to assess the corrosion resistance of treated and untreated steels. In addition, potentiostatic polarization and XPS techniques together with Mott–Schottky curves were applied to determine the composition and properties of the passive films. The results showed that after solution treatment, the grain size of HNS decreased and the grain became more uniform. Although corrosion occurred on HNSs both before and after treatment, solution treatment resulted in greater compactness in passive films, leading to lower carrier density, lower corrosion current density and better corrosion resistance.
Assessing Consumers’ Preference and Loyalty towards Biopolymer Films for Food Active Packaging
Authors: Socaciu Maria-Ioana , Câmpian Veronica , Dabija Dan-Cristian , Fogarasi Melinda , Semeniuc Cristina Anamaria , Podar Andersina Simina , Vodnar Dan Cristian
Published: November 2022

Contemporary society faces numerous food-related challenges: on the one hand, it is becoming increasingly difficult to ensure that people have access to fresh, nutritious, and safe food products around the world, while on the other hand, consumers from ‘low income’ countries are starving, while food products are sometimes discarded because it is difficult to prolong shelf-life. To overcome such challenges, edible active films, called biopolymer films, were developed as materials to cover or wrap food products to extend their shelf-life, as they can offer additional protection. Therefore, this article aims to study consumers’ preference and loyalty towards the innovative, active, green, and sustainable characteristics of biopolymer films for the active packaging of food products. A quantitative empirical investigation was carried out among consumers in an emerging market, pinpointing their behavior toward such a novel food packaging material. The conceptual model designed was assessed using structural equation modelling. The results show that consumers tend to accept and prefer biopolymer-film packaging, as it maintains the characteristics of the product and thus extends its shelf-life. The results also revealed consumers’ openness to eco-sustainable consumption and willingness to pay more for the benefits of this packaging.
Bi2O3-Assisted Sintering of Na3Zr2Si2PO12 Electrolyte for Solid-State Sodium Metal Batteries
Authors: Cen Shangxu , Mei Wentao , Xing Xiangyuan , Zeng Yiwei , Mao Zhiyong , Wang Dajian , Chen Jingjing , Dong Chenlong
Published: November 2022

Solid-state sodium metal batteries using non-flammable solid-state electrolytes are recognized as next-generation energy storage technology in view of their merits of high safety and low cost. However, the lower ion conductivity (below the application requirements of 10−3 S cm−1) and interface issues that exist in electrolytes/electrodes for most solid-state electrolytes hinder their practical application. In this paper, NASICON-type Na3Zr2Si2PO12 (NZSP) electrolytes with enhanced ion conductivity are synthesized by the Bi2O3-assisted sintering method. The influence of the Bi2O3 sintering agent content on the crystalline phase, microstructure, density and ion conductivity as well as the electrochemical performances applied in batteries for the obtained NZSP electrolytes are investigated in detail. With the presence of Bi2O3, the formed Na3Bi(PO4)2 impurity increased the Si/P ratio in the NASICON structure with higher Na+ occupancy, then enhanced the ionic conductivity to a level of 1.27 × 10−3 S cm−1. Unfortunately, the Bi2O3-assisted sintered NZSP shows a degradation in the cycling stability when applied to solid-state sodium batteries because of the decreased interfacial stability with Na anodes. The formation of a Bi-Na alloy during cycling might be conducive to Na dendrite growth in electrolytes, degrading the cycling performance. This work presents a facial method to improve the ion conductivity of NASICON-type electrolytes and gives insight into the interface issues of solid-state sodium metal batteries.
Stability and Application Properties of Surfactant-Free Cosmetic Emulsions: An Instrumental Approach to Evaluate Their Potential
Authors: Tafuro Giovanni , Di Domenico Elisa , Costantini Alessia , Francescato Stefano , Busata Laura , Baratto Giovanni , Semenzato Alessandra
Published: November 2022

Technological innovation in the cosmetic field must necessarily consider not only the safety and efficacy requirements but also the growing attention to environmental issues and the need for sensory pleasure during application to satisfy the consumers’ expectations. This work aimed to formulate an oil-in-water fluid emulsion stabilized by the combination of organic and inorganic powders, namely Zea mays starch and zinc oxide associated at different ratios in presence of a polysaccharidic rheological modifier. After verifying the physical stability of the prototypes with a mechanical stress test in a centrifuge, the rheological analyses were conducted in continuous and oscillatory flow conditions, and the immersion/de-immersion test, conducted using a texture analyzer, allowed identifying the system with the viscoelastic characteristics and the parameters of textures, such as firmness, consistency, and adhesiveness, more suitable for the formulation of skin-care products with low viscosity and high spreadability. Finally, we studied the compatibility of the powders with sunscreen filters and pigments, to optimize the systems and assess their potential use in finished products.
Mechanical and Microstructural Behavior of Tempered CPM® 3V High-Density Sintered Tool Steel
Authors: Hanson Stephen A. C. , Vadiraja Sudhakar
Published: November 2022

The tempering response of CPM® 3V tool steel was investigated via a hardening and tempering heat treatment, tensile testing, fractography, and microstructural evaluation. CPM® 3V tool steel is manufactured using Crucible Particle Metallurgy (CPM®), a proprietary high-density sintering technique developed by Crucible Industries. The hardening and tempering heat treatments were applied to ASTM E8 standard test specimens. Tempering temperature was the experimental variable. The following samples were prepared: As-Hardened (no tempering); tempered at 450 °C, 550 °C, 650 °C, and 700 °C; and As-Received (annealed). Ultimate tensile strength and the yield strength of each treatment was determined using the ASTM E8 standard tensile test. The failed specimens were examined for mode of fracture at macro- and microscopic scales. Reflected light microscopy and a scanning electron microscope (SEM) was used for microstructural characterization. Testing and analysis established the samples tempered at <550 °C were dominated by brittle failure while samples tempered at >550 °C experienced ductile failure. The 550 °C treatment showed mixed ductile and brittle fracture features. This study found that CPM® 3V can be optimized for strength, with good tensile toughness, at a 550 °C tempering temperature. This is consistent with Crucible Industries’ recommended tempering temperature for good wear resistance and toughness.
Direct Phasing of Coiled-Coil Protein Crystals
Authors: Fu Ruijiang , Su Wu-Pei , He Hongxing
Published: November 2022

Coiled-coil proteins consisting of multiple copies of helices take part in transmembrane transportation and oligomerization, and are used for drug delivery. Cross-alpha amyloid-like coiled-coil structures, in which tens of short helices align perpendicular to the fibril axis, often resist molecular replacement due to the uncertainty to position each helix. Eight coiled-coil structures already solved and posted in the protein data bank are reconstructed ab initio to demonstrate the direct phasing results. Non-crystallographic symmetry and intermediate-resolution diffraction data are considered for direct phasing. The retrieved phases have a mean phase error around 30∼40°. The calculated density map is ready for model building, and the reconstructed model agrees with the deposited structure. The results indicate that direct phasing is an efficient approach to construct the protein envelope from scratch, build each helix without model bias which is also used to confirm the prediction of AlphaFold and RosettaFold, and solve the whole structure of coiled-coil proteins.
Variation in Gemological Characteristics in Tsavorites with Different Tones from East Africa
Authors: Ma Yuanmeng , Guo Ying
Published: November 2022

In this paper, the influencing factors of the color and the gemological changes of tsavorites with different tones from East Africa were studied. The gemological characteristics of 35 different green tones in tsavorites were collected based on the results of color measurement, X-ray fluorescence, ultraviolet–visible, infrared and Raman spectroscopy. V and Cr are responsible for the samples’ color: with the increase of vanadium content, lightness L* and chroma C* decreased while hue h° increased, and the hue tends to blueish green. The color of tsavorite is related significantly to the absorption bands at about 430 nm and 605 nm through the UV-VIS spectrum. Under long-wave ultraviolet light, the samples show inert or red fluorescence. The G, H, and I peaks of the infrared spectrum are shifted towards the long-wave direction with the reduction of the V content. The peaks at 275 nm, 412 nm and 545 nm on the Raman spectrum tend to move towards the direction of decreasing wavelength with the increase of V content.
Resilience and Species Accumulation across Seafloor Habitat Transitions in a Northern New Zealand Harbour
Authors: Mangan Stephanie , Bulmer Richard H. , Greenfield Barry L. , Hailes Sarah F. , Carter Kelly , Hewitt Judi E. , Lohrer Andrew M.
Published: November 2022

Biodiversity is crucial for maintaining ecosystem stability and functionality under increasing anthropogenic stress. Part of this resilience comes from having many species performing the same function (functional redundancy) leading to the quantification of community composition and functional redundancy in relation to increasing stress. However, much of the research within coastal ecosystems focuses on distinct areas, rather than whole ecosystems. Here, we investigate the relationship between biodiversity and functional redundancy across two environmental gradients (sediment mud content and water column depth) and different habitat types following a survey of benthic macrofauna and sediment characteristics at 24 sites within Whangārei Harbour, New Zealand. We observed strong gradients in biodiversity which fragmented communities into fewer species that were a subset of the wider community. The lowest biodiversity was observed at muddy, intertidal and shallow subtidal sites which also had the lowest predicted functional redundancy. We show the stronger influence of water column depth on predicted functional redundancy than sediment mud content, highlighting the importance of subtidal regions. Overall, our study highlights the importance of studying the individual contributions of different areas in a landscape to characterise effective colonist pool size and how this can be used to predict recovery potential following disturbance.
Does Temporal and Spatial Diet Alteration Lead to Successful Adaptation of the Eastern Imperial Eagle, a Top Predator?
Authors: Demerdzhiev Dimitar , Boev Zlatozar , Dobrev Dobromir , Nedyalkov Nedko , Petrov Tseno
Published: November 2022

Predator–prey interactions may be linked to different temporal or spatial patterns, including dynamics in prey populations. Therefore, understanding the adaptive capacity and how top predators respond to shifts in prey abundance and availability is crucial for their conservation. In this study, we investigated the diet pattern of the endangered Eastern Imperial Eagle facing long-term and large-scale changes. We studied the abundance variation of its profitable prey, sousliks, and how it reflected on eagle population trajectories in a regional and temporal context. We found a significant diet alteration expressed in large decrease of brown hare (β2 = −0.83), poultry (β2 = −0.81), gulls (β2 = −0.71), and water birds (β2 = −0.57), and an obvious increase of northern white-breasted hedgehog (β2 = 0.61) and doves (β2 = 0.60). Raptors and owls raised their participation (β2 = 0.44), but white stork and different reptiles supplied more biomass. Abundance of European souslik decreased through the studied periods (adjusted R2 = 0.25, p < 0.001) which accounted for the lower proportion of this prey in the eagle’s diet. Nevertheless, the eagle population successfully adapted and significantly increased (β2 = 0.97) in most of the distribution area. The trophic strategy used by this top predator related to opportunistic foraging represents an ecological advantage that allows the species to adapt to different habitats and guarantees its future. The observed prolonged diet alteration could result in a significant negative attitude among different groups such as hunters, pigeon fanciers, and poultry keepers towards eagles. Therefore, enhanced communication with key stakeholders is needed. Conservation efforts should be focused also on the preservation of the species’ main foraging habitats and the restoration of damaged ones so as to maintain the good conditions of both primary food source and subsequent prey.
Description of a New Species of the Genus Cryptomonas (Cryptophyceae: Cryptomonadales), Isolated from Soils in a Tropical Forest
Authors: Martynenko Nikita , Kezlya Elena , Gusev Evgeniy
Published: November 2022

A new species, Cryptomonas tropica sp. nov., is described from Cat Tien National Park (Vietnam) based on morphological and molecular data. Strains of the new species were isolated from soil, which is an unusual environment for photosynthetic cryptomonads. This species has elliptical cells in ventral view and a single plastid notched into several irregular lobes without microscopically visible pyrenoids. Phylogenetic relationships inferred from nuclear-encoded SSU, LSU, ITS2 rDNA and psbA cpDNA show that the new species forms an independent branch on the phylogenetic tree of the genus Cryptomonas. In all phylogenetic analyses, this lineage was sister to clades containing other small-celled, pyrenoid-less species: Cryptomonas erosa, C. parmana, C. macilenta, C. obovoidea and C. commutata. C. tropica has been observed in two distant localities in Cat Tien National Park.
Detection and Morphological Analysis of Micro-Ruptured Cortical Arteries in Subdural Hematoma: Three-Dimensional Visualization Using the Tissue-Clearing Clear, Unobstructed, Brain/Body Imaging Cocktails and Computational Analysis Method
Authors: Funayama Kazuhisa , Tainaka Kazuki , Koyama Akihide , Katsuragi-Go Rieka , Nishikawa-Harada Natsumi , Higuchi Ryoko , Aoyama Takashi , Watanabe Hiraku , Takahashi Naoya , Takatsuka Hisakazu
Published: November 2022

One of the causes of bleeding in subdural hematoma is cortical artery rupture, which is difficult to detect at autopsy. Therefore, reports of autopsy cases with this condition are limited and hence, the pathogenesis of subdural hematoma remains unclear. Herein, for the detection and morphological analysis of cortical artery ruptures as the bleeding sources of subdural hematoma, we used the tissue-clearing CUBIC (clear, unobstructed, brain/body imaging cocktails and computational analysis) method with light-sheet fluorescence microscopy and reconstructed the two-dimensional and three-dimensional images. Using the CUBIC method, we could clearly visualize and detect cortical artery ruptures that were missed by conventional methods. Indeed, the CUBIC method enables three-dimensional morphological analysis of cortical arteries including the ruptured area, and the creation of cross-sectional two-dimensional images in any direction, which are similar to histopathological images. This highlights the effectiveness of the CUBIC method for subdural hematoma analysis.
The Price for Inclusion: Financial/Educational Dilemmas in the Inclusive School System in Denmark
Authors: Tegtmejer Thyge
Published: November 2022

This qualitative case study investigates the rationales, dilemmas, and shortcomings of the so-called “inclusion-promoting steering models” in which Danish schools have to pay a price for every student they cannot include in their school. For more than 10 years, the government has promoted such financial steering models and a rising number of municipalities have adopted the system, so that more than one-half of the existing Danish municipalities work with them. According to its advocates, this model supports the inclusion of students in schools in several direct ways. This case study shows that this model is based on some strong rationales, as it offers opportunities to promote the development of inclusive schools. However, the study also reveals that this comes at a price, as the model sometimes poses difficult dilemmas on school leaders and hinders the inclusion of all students.
Using an Evidence-Informed Approach to Improve Students’ Higher Order Thinking Skills
Authors: Hubers Mireille Desirée
Published: November 2022

This study aimed to determine why university students performed relatively low on a writing assignment. In phase 1, questionnaire and performance data were collected and analyzed. This evidence-informed approach revealed that students’ relatively low performance was caused by their relatively underdeveloped higher order thinking skills. A six-step research-informed procedure was designed to assist students’ development of these skills. In turn, questionnaire data, performance data and observational data were collected in phase 2 to determine the effectiveness of the design and the quality of the implementation. The results indicated that students improved their higher order thinking skills. Alternative explanations did not play a role; the designed procedure was implemented with high fidelity and positively rated by the students. This study can aid university teachers in designing course materials for the development of students’ higher order thinking skills.
Methodology for Improving High-Power Harmonic Measurement Accuracy and Stability
Authors: Wang Lei , Zhang Jinyi
Published: November 2022

With continued dimension scaling of the semiconductor devices, the parasitic parameters become increasingly obvious and it affects the device performance directly. The harmonic distortion is one of the key factors to limit the RF system bandwidth resource and channel capability. Therefore, it is crucial to precisely extract the nonlinear index of the device and system. High-precision harmonic distortion extraction on a device’s intrinsic characteristics could be beneficial not only to device modeling but also to circuit design. However, the harmonic distortion measurement is highly sensitive to the peripheral circuit and instrumentations, especially in high power stimulus; its repeatability and stability are also hard to control. This paper aims to contribute to the subject by extending the measurement methodology, combining isolation compensation with a dual trace phase tuning (DTPT) technique to obtain the optimal harmonic value. As shown by the experiment results, the optimized approach could achieve high measurements of both accuracy and stability. The proposed methodology is validated with measurement data and compared with conventional measurement architecture. The assessment results prove that the proposed methodology could improve 30.66% and 28.84% measurement accuracy both on second and third harmonics. Simultaneously, the proposed methodology decreases gauge repeatability and reproducibility (GRR) from 56.49% to 7.13%.
How Multi-Criterion Optimized Control Methods Improve Effectiveness of Multi-Zone Building Heating System Upgrading
Authors: Esmaeilzadeh Ahmad , Deal Brian , Yousefi-Koma Aghil , Zakerzadeh Mohammad Reza
Published: November 2022

This paper aims to develop multi-objective optimized control methods to improve the performance of retrofitting building heating systems in reducing consumed energy as well as providing comfortable temperature in a multi-zone building. While researchers evaluate various controllers in specific systems, providing a comprehensive controller for retrofitting the existing heating systems of multi-zone buildings is less investigated. A case study approach with a four-story residential building is simulated. The building energy consumption is modeled by EnergyPlus. The model is validated with energy data. Then, the building steam system model is upgraded, and in the other case, renewed by a hydronic system instead of a steam one. Three optimized controller groups are developed, including Model Predictive Controller (MPC), fuzzy controllers (Fuzzy Logic Controller (FLC) and an Optimized Fuzzy Sliding Mode Controller (OFSMC)), and optimized traditional ones. These controllers were applied to the upgraded steam and hydronic heating systems. The control methods affected the tuning of the boiler feed flow by regulating the condensing cycle and circulating the pump flow of the hydronic system. Accordingly, renewing the heating system improves energy efficiency by up to 29% by implementing a hydronic system instead of the steam one. The fuzzy controllers increased renewing effectiveness by providing comfortable temperatures and reducing building environmental footprints by up to 95% and 12%, respectively, compared with an on/off controller baseline.
Smart Energy for a Smart City: A Review of Polish Urban Development Plans
Authors: Yarashynskaya Aksana , Prus Piotr
Published: November 2022

Smart Energy is a key element of a Smart City concept and understanding the current state and prospective developments of Smart Energy approaches is essential for the effective and efficient energy supply for the needs of the exponentially growing energy demands of contemporary cities. This review analyzes the inclusion of the Smart Energy agenda in Polish Smart City development plans applying content analysis methodology. The stakeholders’ involvement, spatial dimensions, Smart Energy conceptions, and Smart Energy key sectors were identified as the most commonly referenced Smart Energy agenda components. Stakeholders’ involvement in Smart Energy agendas covers all the crucial key actors—universities, local businesses, and public governance institutions. The spatial dimension components of the Smart Energy agenda comprise the individual, city, regional (sub-regional), country, and international (EU) levels, with the natural dominance of the city’s level. The Smart Energy conceptions component shows a profound disparity in the referencing frequency of the four “core” Smart Energy conceptions (renewable energy, energy efficiency, energy-saving technologies, and energy security) and “peripheral” Smart Energy conceptions. Buildings, transportation, lighting, and manufacturing sectors were found to be the only sectors referenced in reviewed urban development plans with regard to the Smart Energy agenda. The research results contribute to the better understanding of the Polish Smart Energy and Smart City planning landscapes and can be helpful in improving the cities’ spatial planning strategies.
Geology and Geochemistry of the Hydrocarbon Compositional Changes in the Triassic Montney Formation, Western Canada
Authors: Chalmers Gareth R. L. , Lacerda Silva Pablo , Bustin Amanda A. , Sanlorenzo Andrea , Bustin R. Marc
Published: November 2022

The geochemistry of produced fluids has been investigated in the Triassic Montney Formation in the Western Canadian Sedimentary Basin (WCSB). Understanding the geochemistry of produced fluids is a valuable tool in the exploration and development of a complex petroleum system such as the Montney Formation. The petroleum system changes from in situ unconventional reservoirs in the west to more conventional reservoirs that contain migrated hydrocarbons to the east. The workflow of basin modeling and mapping of isomer ratio calculations for butane and pentane as well as the mapping of excess methane percentage was used to highlight areas of gas compositional changes in the Montney Formation play area. This workflow shows the migration of hydrocarbons from deeper, more mature areas to less mature areas in the east through discrete pathways. Methane has migrated along structural elements such as the Fort St. John Graben as well as areas that have seen changes in higher permeability lithologies (i.e., well 14-23-74-8W6M). Excess methane percentage calculations highlight changes due to fluid mixing from hydrocarbon migration. The regional maturation polynomial regression line was used to determine the gas dryness percentage for each well on the basis of its maturation level determined by the butane isomer ratio. The deviation from the calculated gas dryness according to the regression was determined as an excess methane percentage. The British Columbia (BC) Montney play appears to have hydrocarbon compositions that reflect an in situ generation, while the Montney play in Alberta (AB) has a higher proportion of its hydrocarbon volumes from migrated hydrocarbons. The workflow provides a better understanding of the hydrocarbon system to optimize operations and increase production efficiency. Understanding the distribution of gas compositions within a play area will provide key information on the liquid and gas phases present and an understanding of how gas composition may change over the well life, as well as helping to maximize liquid recovery during well operations.
Tuning Model Predictive Control for Rigorous Operation of the Dalsfoss Hydropower Plant
Authors: Jeong Changhun , Sharma Roshan
Published: November 2022

Model predictive control is considered an attractive control strategy for the operation of hydropower station systems. It is due to the operational constraints or requirements of the hydropower system for safe and eco-friendly operation. However, it is mandatory to tune the model predictive control to achieve its best and most efficient performance. This paper determines the appropriate tunning on the weight parameters and the length of the prediction horizon for implementing model predictive control on the Dalsfoss hydropower system. For that, several test sets of the weight parameter for the optimal control problem and different lengths of the prediction horizon are simulated and compared.
Recurrent Wavelet Fuzzy Neural Network-Based Reference Compensation Current Control Strategy for Shunt Active Power Filter
Authors: Chen Cheng-I , Chen Yeong-Chin , Chen Chung-Hsien
Published: November 2022

The usage of a shunt active power filter (SAPF) is one of the helpful means to mitigate the reactive power and harmonic current of a power grid. The compensation performance of the SAPF is related to the accuracy of the reference voltage extraction from the utility grid, the control stability of the DC-link voltage regulation, and the synchronization between the source voltage and the reference compensation current. To modify the performance of the SAPF for the harmonic compensation, the control strategy of the SAPF reference compensation current based on the recurrent wavelet fuzzy neural network (RWFNN) is proposed in this paper. There are three sections in the proposed control strategy, including the regulated fundamental positive-sequence extraction (section A), DC-link voltage regulation (section B), and calculation of reference compensation current (section C). By regulating the analysis mechanism with the variation of fundamental frequency in the section A, the accurate reference voltage would be obtained. The control stability for the regulation of the DC-link voltage can be accomplished by applying the RWFNN-based controller in the section B. With the synchronized reference voltage in the section A and the estimated control current in the section B, the reference compensation current can be correctly obtained in the section C. From the case studies with the real-time simulator produced by OPAL-RT Technologies Inc., the effectiveness of proposed control strategy for the SAPF reference compensation current can be verified.
A Comprehensive Review on Current Performance, Challenges and Progress in Thin-Film Solar Cells
Authors: Sivaraj Santhosh , Rathanasamy Rajasekar , Kaliyannan Gobinath Velu , Panchal Hitesh , Jawad Alrubaie Ali , Musa Jaber Mustafa , Said Zafar , Memon Saim
Published: November 2022

Due to the recent surge in silicon demand for solar modules, thin-film photovoltaic (PV) modules have a potential to penetrate the market in significant numbers. As an alternate candidate, thin film technologies in PVs have the ability to achieve better performance. The competing thin-film PV technologies have the flexibility to adapt to any sort of curvature compared to rigid solar cells (SCs). Due to the peculiar characteristics of newer solar materials, stability issues, reflection losses, advancements in electrode materials and dopant materials with a photoactive layer are current challenges driving the industrial-academic voyage of development of solar materials for the betterment of Photo-conversion Efficiency (PCE). Based on the photoactive materials used over time, SC evolution was broadly classified into first, second and third generation SCs. In this review, the basic working mechanisms, various materials used, drawbacks and stability issues of different SCs are discussed extensively. Thin film SCs tend to absorb certain elastic deformations due to their flexible nature and to a certain extent. According to the NREL efficiency chart, multi-junctional SCs exhibit enhanced efficiency as compared to the other SCs. Among the third-generation SCs, the perovskite/Si tandem architecture shows a maximum efficiency of approximately 29%. Thin film flexible SCs find application in various sectors such as automobile, defense and/or energy storage devices
Prototyping and Experimental Investigation of Digital Hydraulically Driven Knee Exoskeleton
Authors: Rituraj Rituraj , Scheidl Rudolf , Ladner Peter , Lauber Martin , Plöckinger Andreas
Published: November 2022

Digital hydraulic drives are known for their superior efficiency, power density, and robustness. Such advantages make them an attractive alternative (to electric drives) for actuation of exoskeleton devices. This work presents development of a prototype for such a digital hydraulically driven knee exoskeleton and its experimental testing. The device uses two miniature hydraulic cylinders and a novel mechanism to translate the linear motion to rotary motion. The device is controlled via a passive control method in the stance phase and a simplified model predictive control method in the swing phase. In this work, the design of the exoskeleton device is optimized with respect to compactness and weight. Next, the features of the design are further refined to ensure that the device is able to support the operational loads. This design is then realized into a prototype with a mixture of inhouse manufactured parts and procured components. Finally, via experimental tests, the performance of the design and the control strategy are investigated. Certain drawbacks related to valve size and overall weight are observed in the prototype, which will be addressed in future studies.
Optimal Management of Energy Communities Hosting a Fleet of Electric Vehicles
Authors: Zanvettor Giovanni Gino , Casini Marco , Giannitrapani Antonio , Paoletti Simone , Vicino Antonio
Published: November 2022

In this paper, we study the problem of managing an energy community hosting a fleet of electric vehicles for rent. On the day ahead, service requests for electric vehicles are submitted to the community. Then, the optimal request-to-vehicle assignment has to be found, as well as the optimal charging schedule of vehicle batteries. A suitable model is presented and included in an existing energy community architecture. The overall community management problem is formulated as a bi-level model, featuring two nested optimization problems. The optimal request-to-vehicle assignment requires the solution of a mixed-integer linear program. To reduce the computational complexity, a heuristic solution to the assignment problem is presented. Numerical results show that participation in the community grants a remarkable reduction in the electric vehicle charging cost. The adoption of the heuristic assignment solution provides a dramatic reduction in the computation time required to solve the bi-level model. At the same time, the level of suboptimality introduced appears to be negligible, being less than 1% in most of the considered cases.
Recent Progress in Transparent Conductive Materials for Photovoltaics
Authors: Maurya Sandeep Kumar , Galvan Hazel Rose , Gautam Gaurav , Xu Xiaojie
Published: November 2022

Transparent conducting materials (TCMs) are essential components for a variety of optoelectronic devices, such as photovoltaics, displays and touch screens. In recent years, extensive efforts have been made to develop TCMs with both high electrical conductivity and optical transmittance. Based on material types, they can be mainly categorized into the following classes: metal oxides, metal nanowire networks, carbon-material-based TCMs (graphene and carbon nanotube networks) and conjugated conductive polymers (PEDOT:PSS). This review will discuss the fundamental electrical and optical properties, typical fabrication methods and the applications in solar cells for each class of TCMs and highlight the current challenges and potential future research directions.
Thermocouple Effective Length under Sinusoidal Gas Temperature Condition
Authors: Huang Qinghuang , Liu Zhiwei , Li Xingyou , Wang Peiyong
Published: November 2022

When a thermocouple is used to measure gas temperature, the measured temperature is the thermocouple bead temperature, which is not equal to the gas temperature. The bead temperature results from its energy balance. Through the wire convection and conduction, the temperature of the bead is related to the gas temperature within a certain geometric range around it, and this range is quantified by the effective length. Under the sinusoidal incoming gas temperature condition, the analytical expression for the effective length is deduced, and its accuracy is validated by the one-dimensional numerical solution. The differences between the analytical and numerical effective lengths are less than 10.5% for the test cases. Similar to that under the uniform incoming gas temperature condition, the effective length under the sinusoidal gas temperature condition increases with the thermal conductivity and the diameter of the wire and decreases with the heat transfer coefficient of the wire. The influence of the amplitude, wavelength and phase of the gas temperature on the effective length are very weak, meaning that the theoretical expression under the uniform gas temperature can calculate the effective length under the non-uniform gas temperature with good accuracy.
Numerical Investigations of the Vertical Axis Wind Turbine with Guide Vane
Authors: Kołodziejczyk Krzysztof , Ptak Radosław
Published: November 2022

More than ever, the generation of energy from renewable sources has become one of the most critical and challenging areas of human activity. This is the result of a number of factors acting simultaneously, including the highly publicized greenhouse effect, the need to reduce CO2 emissions, the dwindling of natural resources and thus the need to protect them, including the preservation of wealth (among other natural resources) for future generations. This paper presents a numerical investigation of the operation of a vertical axis wind turbine with guide vanes. The work analyzes the obtained power on the turbine rotor for different numbers of rotor blades and different numbers of guide vanes, as well as for different proportions of the width of the rotor ring and the guide ring. The analyses carried out point to the potential feasibility of using this type of design in practice. The obtained power coefficient is higher than that of classical vertical axis wind turbines. The analyses also indicate that the proposed design solution can be optimized to increase the efficiency of wind energy extraction.