bluuebunny/crossref_metadata_2025 huggingface dataset:
Affinity Selection in Germinal Centers: Cautionary Tales and New Opportunities
Authors: Faro Jose , Castro Mario
Published: April 2021

Our current quantitative knowledge of the kinetics of antibody-mediated immunity is partly based on idealized experiments throughout the last decades. However, new experimental techniques often render contradictory quantitative outcomes that shake previously uncontroversial assumptions. This has been the case in the field of T-cell receptors, where recent techniques for measuring the 2-dimensional rate constants of T-cell receptor–ligand interactions exposed results contradictory to those obtained with techniques measuring 3-dimensional interactions. Recently, we have developed a mathematical framework to rationalize those discrepancies, focusing on the proper fine-grained description of the underlying kinetic steps involved in the immune synapse. In this perspective article, we apply this approach to unveil potential blind spots in the case of B-cell receptors (BCR) and to rethink the interactions between B cells and follicular dendritic cells (FDC) during the germinal center (GC) reaction. Also, we elaborate on the concept of “catch bonds” and on the recent observations that B-cell synapses retract and pull antigen generating a “retracting force”, and propose some testable predictions that can lead to future research.
Dual Impact of a Benzimidazole Resistant β-Tubulin on Microtubule Behavior in Fission Yeast
Authors: Minagawa Mamika , Shirato Minamo , Toya Mika , Sato Masamitsu
Published: April 2021

The cytoskeleton microtubule consists of polymerized αβ-tubulin dimers and plays essential roles in many cellular events. Reagents that inhibit microtubule behaviors have been developed as antifungal, antiparasitic, and anticancer drugs. Benzimidazole compounds, including thiabendazole (TBZ), carbendazim (MBC), and nocodazole, are prevailing microtubule poisons that target β-tubulin and inhibit microtubule polymerization. The molecular basis, however, as to how the drug acts on β-tubulin remains controversial. Here, we characterize the S. pombe β-tubulin mutant nda3-TB101, which was previously isolated as a mutant resistance to benzimidazole. The mutation site tyrosine at position 50 is located in the interface of two lateral β-tubulin proteins and at the gate of a putative binging pocket for benzimidazole. Our observation revealed two properties of the mutant tubulin. First, the dynamics of cellular microtubules comprising the mutant β-tubulin were stabilized in the absence of benzimidazole. Second, the mutant protein reduced the affinity to benzimidazole in vitro. We therefore conclude that the mutant β-tubulin Nda3-TB101 exerts a dual effect on microtubule behaviors: the mutant β-tubulin stabilizes microtubules and is insensitive to benzimidazole drugs. This notion fine-tunes the current elusive molecular model regarding binding of benzimidazole to β-tubulin.
A Paper-Based Potentiometric Platform for Determination of Water Hardness
Authors: Bouhoun Mohammed L. , Blondeau Pascal , Louafi Yamina , Andrade Francisco J.
Published: April 2021

A novel paper-based potentiometric platform for the simple and fast monitoring of water hardness is presented. First, potentiometric ion-selective electrodes for calcium and magnesium printed on a paper substrate were built and optimized. These sensors, which display near-Nernstian sensitivity, were used for the determination of the concentration of these cations and the calculation of the water hardness. Second, the incorporation of a solid-state reference electrode allowed building an integrated paper-based potentiometric cell for the determination of the hardness of artificial and real samples (mineral waters). The validation of the results shows good ability to predict hardness in the conventional scale. Truly decentralized measurements were demonstrated by integration of a miniaturized instrument and dedicated software in a portable device. The measurements were able to be performed in just under two minutes, including a two-point calibration. Since the method is simple to use and cost-effective, it can be implemented in domestic and industrial settings.
Incorporating Cascade Effects of Genetic Testing in Economic Evaluation: A Scoping Review of Methodological Challenges
Authors: Cernat Alexandra , Hayeems Robin Z. , Prosser Lisa A. , Ungar Wendy J.
Published: April 2021

Cascade genetic testing is indicated for family members of individuals testing positive on a genetic test, and is particularly relevant for child health because of their vulnerability and the long-term health and economic implications. Cascade testing has patient- and health system-level implications; however cascade costs and health effects are not routinely considered in economic evaluation. The methodological challenges associated with incorporating cascade effects in economic evaluation require examination. The purpose of this scoping review was to identify published economic evaluations that considered cascade genetic testing. Citation databases were searched for English-language economic evaluations reporting on cascade genetic testing. Nineteen publications were included. In four, genetic testing was used to identify new index patients—cascade effects were also considered; thirteen assessed cascade genetic testing strategies for the identification of at-risk relatives; and two calculated the costs of cascade genetic testing as a secondary objective. Methodological challenges associated with incorporating cascade effects in economic evaluation are related to study design, costing, measurement and valuation of health outcomes, and modeling. As health economic studies may currently be underestimating both the cost and health benefits attributable to genetic technologies through omission of cascade effects, development of methods to address these difficulties is required.
Quality Characteristics of Semi-Moist Apricot-Cornflakes: Effect of Different Composite Coating Application and Storage Time
Authors: Sakooei-Vayghan Roghieh , Peighambardoust Seyed Hadi , Domínguez Rubén , Pateiro Mirian , Lorenzo José M.
Published: April 2021

The effect of different composite coatings on quality of semi-moist apricot cubes mixed with cornflakes was investigated during 180 days of storage. The apricot cubes were osmotically dehydrated (OD) and coated before hot-air drying (HAD) at 60 °C. Chitosan-bees wax (CBW) and whey protein isolate-bees wax-oleic acid (WPI-BW-OA) coatings were applied after HAD and the samples were added to cornflakes. Application of OD and pectin-ascorbic acid (Pec-AA) coating (prior to HAD) and WPI-BW-OA coating (after HAD) led to significant retention of total phenol compounds, β-carotene and antioxidant activity in apricot cubes compared to uncoated and CBW-coated samples. WPI-BW-OA-coated samples gave significantly higher L* values (lighter color) and b* values (more creamy or yellowish color) and lower a* values (less reddish color) and browning values than control followed by CBW-coated apricots at any time of storage (p < 0.05). The rate of apricot moisture loss and cornflakes moisture gain was higher in uncoated apricot cubes, followed by CBW- and WPI-BW-OA-coated samples. Application of WPI-BW-OA coating was effective in retaining the crispness measured by lower firmness (Fmax) values in cornflakes upon storage. Based on the obtained results, WPI-BW-OA coating allowed effectively preserving the quality characteristics of semi-moist apricot cubes and cornflakes components in the mixed state.
Effects of Wollastonite on Fire Properties of Particleboard Made from Wood and Chicken Feather Fibers
Authors: Taghiyari Hamid R. , Militz Holger , Antov Petar , Papadopoulos Antonios N.
Published: April 2021

The present study was carried out primarily to investigate the fire properties of particleboards with 5% and 10% feather content. With regard to the flammability of chicken feathers, separate sets of panels were produced with 10% wollastonite content to determine to what extent it could help mitigate the negative effects of the addition of flammable feathers on the fire properties. It was concluded that the inclusion of 5% of chicken feathers can be considered the optimum level, enough to procure part of the ever-growing needs for new sources of raw material in particleboard manufacturing factories, without sacrificing the important fire properties. Moreover, the addition of 10% wollastonite is recommended to significantly improve the fire properties, making the panels more secure in applications with higher risks of fire. It is further stated thata chicken feather content of 10% is not recommended as it significantly deteriorates all properties (including physical, mechanical, and fire properties).
Improved Noise and Device Performances of AlGaN/GaN HEMTs with In Situ Silicon Carbon Nitride (SiCN) Cap Layer
Authors: Choi Yeo-Jin , Lee Jae-Hoon , Choi Jin-Seok , An Sung-Jin , Hwang Young-Min , Roh Jae-Seung , Im Ki-Sik
Published: April 2021

We investigated the effects of in situ silicon carbon nitride (SiCN) cap layer of AlGaN/GaN high-electron mobility transistors (HEMTs) on DC, capacitance-voltage (C-V) and low-frequency noise (LFN). The proposed device with SiCN cap layer exhibited enhanced drain current, reduced gate leakage current, low interface trap density (Dit), and high on/off ratio thanks to the passivation effect, compared to the device without SiCN cap layer. Both devices clearly showed 1/f noise behavior with carrier number fluctuations (CNF), regardless of the existence of SiCN cap layer. The proposed device presented the relative low trap density (Nit) and reduced access noise due to the effective surface passivation in source-drain access region compared to the device without SiCN cap layer. From the improved DC, C-V and noise results of the proposed device, the in situ SiCN cap layer plays an important role in the passivation layer and gate oxide layer in AlGaN/GaN HEMT.
Calcite Nanocrystals Investigated Using X-ray Absorption Spectroscopy
Authors: Singh Varsha , Paidi Anil Kumar , Shim Cheol-Hwee , Kim So-Hee , Won Sung-Ok , Singh Jitendra Pal , Lee Sangsul , Chae Keun-Hwa
Published: April 2021

For the present work, calcite nanocrystals were grown by annealing precursors at 500 °C. These precursors were obtained by three different thermal schemes. Among these schemes, two involve heating at 100 °C for 16 h and 16 + 24 h, respectively. In the third scheme, heating was performed at 100 °C for 16 h, followed by annealing at 300 °C for 24 h. X-ray diffraction studies, followed by Fourier transform infrared and Raman spectroscopic studies, exhibited the formation of calcite phase of calcium carbonate. Transmission electron microscopy showed that particle sizes of synthesized calcite nanocrystals were in the range of 25–40 nm. Onsets of shape change were also observed with different thermal schemes, using these measurements. X-ray absorption spectroscopy envisaged that the coordination numbers of Ca-O and Ca-Ca shell were not influenced by the thermal schemes; however, bond lengths of these shells were modified. This study in the near edge region evidenced the manifestation of a local electronic structure of calcite when kept in an open environment, depending upon different thermal schemes.
Dispersion Diagram of Trigonal Piezoelectric Phononic Structures with Langasite Inclusions
Authors: Miranda Edson , Aranas Clodualdo , Rodrigues Samuel , Silva Hélio , Reis Gedeon , Paiva Antônio , Dos Santos José
Published: April 2021

The dispersion relation of elastic Bloch waves in 1-3 piezoelectric phononic structures (PPnSs) with Langasite (La3Ga5SiO14) inclusions in a polymeric matrix is reported. Langasite presents promising material properties, for instance good temperature behaviour, high piezoelectric coupling, low acoustic loss and high quality factor. Furthermore, Langasite belongs to the point group 32 and has a trigonal structure. Thus, the 2-D bulk wave propagation in periodic systems with Langasite inclusions cannot be decoupled into XY and Z modes. The improved plane wave expansion (IPWE) is used to obtain the dispersion diagram of the bulk Bloch waves in 1-3 PPnSs considering the classical elasticity theory and D3 symmetry. Full band gaps are obtained for a broad range of frequency. The piezoelectricity enhances significantly the band gap widths and opens up a narrow band gap in lower frequencies for a filling fraction of 0.5. This study should be useful for surface acoustic wave (SAW) filter and 1-3 piezocomposite transducer design using PPnSs with Langasite.
Design of Comb Crack Resistant Milling Inserts: A Comparison of Stresses, Crack Propagation, and Deformation Behavior between Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 CVD Coatings
Authors: Moreno Maiara , El Azhari Idriss , Apel Daniel , Meixner Matthias , Wan Wei , Pinto Haroldo , Soldera Flavio , Mücklich Frank , García José
Published: April 2021

Investigations on comb crack resistance of milling inserts coated with chemical vapor deposition (CVD) Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 showed a distinct wear evolution in both systems. Wear studies revealed that the appearance of comb cracks is connected to the initial CVD cooling crack network. Micropillar compression tests indicated a brittle intergranular fracture mechanism for the Ti(C,N) layer and a transgranular fracture accompanied with signs of plastic deformation for the Zr(C,N) coating. Additionally, for the Zr(C,N) based system, a compressive stress condition in the temperature range of interest (200–600 °C) was determined by in-situ synchrotron X-ray diffraction. The set of residual compressive stresses together with the ability of the Zr(C,N) layer to deform plastically are key features that explain the enhanced resistance to comb crack wear of the Zr(C,N) based system in milling of cast iron.
Dissolved Oxygen-And Temperature-Dependent Simulation of the Population Dynamics of Moon Jellyfish (Aurelia coerulea) Polyps
Authors: Jin Hongsung , Kim Kwangyoung , Choi Ilsu , Han Dongyeob
Published: April 2021

As the extent of hypoxia in coastal waters increases, the survivorship of jellyfish polyps relative to that of competing sessile organisms often increases, enabling them to reproduce more prolifically, leading to a medusa bloom in the following year. Quantifying the population of polyps can be used to predict when these blooms will occur. We used a time-delayed logistic equation to quantify the response to variable dissolved oxygen (DO) concentrations and temperatures in a population of moon jellyfish (Aurelia coerulea) polyps on substrates that carried competing sessile organisms. The availability of substrate depends on the DO threshold for each competitor, and substrates only become available to the polyps during hypoxic periods. We used the median sublethal concentration (SLC50) thresholds of hypoxia for different groups of benthic organisms to calculate the DO-dependent survivorship of A. coerulea polyps competing on the substrate. Since the median lethal time (LT50) for cnidarians is close to 240 h, we chose a 10-day delay in the time-delayed logistic equation. The carrying capacity is determined every 10 days depending on DO concentrations and temperature. The polyps reproduce by budding at a temperature-dependent rate after settling on the substrate during the hypoxic period, and thus, the annual polyp reproduction rate is determined by multiplying the temperature-dependent budding rate by the DO-dependent survivorship. The duration of hypoxia is a key factor determining the polyp population, which can increase more as the duration of hypoxia increases. Modeling simulations were compared to observed data. In this model, the DO and temperature distribution data make it possible to quantify variations in the population of the A. coerulea polyps, which can be used to predict the abundance and appearance of medusa the following year.
Incidence and Clinical Implications of Autoimmune Thyroiditis in the Development of Acne in Young Patients
Authors: Endres Laura , Tit Delia Mirela , Bungau Simona , Pascalau Nicoleta Anamaria , Maghiar Țodan Laura , Bimbo-Szuhai Erika , Iancu Gabriela Mariana , Negrut Nicoleta
Published: April 2021

Autoimmune thyroiditis (AIT) is on the rise among the population, and is frequently associated with patients with acne vulgaris, especially females aged between 18–55 years old. The connection between the two is not fully elucidated. In this study, 236 patients diagnosed with acne in the dermatological office of the private Pelican Hospital and in few private dermatological offices from Oradea, Romania, during January 2018–December 2020, aged between 12 and 55 years old, were endocrinologically investigated to determine AIT and its influence on the severity of the acne. The values for the thyroid antibodies and thyroid-stimulating hormone (TSH) were determined for all of the subjects. The frequency of AIT in the study group was 72% and was associated with severe acne (p < 0.001). Patients with AIT with normal or hypofunction had more frequent severe acne than those with hyperfunction (p < 0.001, p = 0.002). The TSH and anti thyroidperoxidase (TPO) values did not influence the severity of the acne (p = 0.494; p = 0.111), while the anti-TG values were associated with severe acne (p = 0.007). The risk analysis indicated that raised values of anti-TPO (2.91 times greater) correlated with high anti-thyroglobulin (TG) values (4.36 times greater) doubled the risk of developing severe acne in patients. In acne evolution, the existence of AIT involves significant modifications.
Kinesiophobia in Stroke Patients, Multiple Sclerosis and Parkinson’s Disesase
Authors: Wasiuk-Zowada Dagmara , Knapik Andrzej , Szefler-Derela Justyna , Brzęk Anna , Krzystanek Ewa
Published: April 2021

Background: Stroke (S), multiple sclerosis (MS), Parkinson’s disease (PD) are chronic neurological diseases that are a challange for public health and represent a real social problem. Physical activity (PA) improves functional performance, reduces various symptoms in PD and MS, in stroke- reduced neurological impairment of patients and provides a chance for independence. One of the main obstacles in successful rehabilitation is patients’ movement passivity. The reason might be the psychological aspects, in particular fear of movement—kinesiophobia. Aim: To determine how many patients with S, MS, and PD suffer from kinsiophobia and what factors influence this process. Methods: Fifty patients after stroke, eighty one MS patients and sixty one PD patients were consecutively recruited from hospital and outpatients clinics. The sociodemographic data, self- assesment of fitness, Visual Analogue Scale (VAS) for pain, Tampa Scale of Kinesiophobia (TSK) and The Modified Baecke Questionnarie for Older Adults for physical activity were collected. A score >37 was considered to indicate a high level of kinesiophobia according to the TSK. Results: High level of kinesiophobia was shown in 66.67% of the subjects. TSK medians in particular illnesses were above the cut-off score and amounted: S—42.50 points; MS—38 points; PD—42.00 points. Regression showed 15% of fluctuation of variance (R2 = 0.1498; p < 0.0001), where regression factor showed: for mobility self-assessment: b = −0.2137 and for the age b = 0.0065. Conclusions: Kinesiophobia among the patients suffering from S, MS and PD concerns most of the subjects. Predictors of kinesiophobia are: limitations connected with functioning and age. The meaning of kinesiophobia in neurological disorders requires further research.
A Residual Network and FPGA Based Real-Time Depth Map Enhancement System
Authors: Li Zhenni , Sun Haoyi , Gao Yuliang , Wang Jiao
Published: April 2021

Depth maps obtained through sensors are often unsatisfactory because of their low-resolution and noise interference. In this paper, we propose a real-time depth map enhancement system based on a residual network which uses dual channels to process depth maps and intensity maps respectively and cancels the preprocessing process, and the algorithm proposed can achieve real-time processing speed at more than 30 fps. Furthermore, the FPGA design and implementation for depth sensing is also introduced. In this FPGA design, intensity image and depth image are captured by the dual-camera synchronous acquisition system as the input of neural network. Experiments on various depth map restoration shows our algorithms has better performance than existing LRMC, DE-CNN and DDTF algorithms on standard datasets and has a better depth map super-resolution, and our FPGA completed the test of the system to ensure that the data throughput of the USB 3.0 interface of the acquisition system is stable at 226 Mbps, and support dual-camera to work at full speed, that is, 54 fps@ (1280 × 960 + 328 × 248 × 3).
Continuance Intention of Augmented Reality Textbooks in Basic Design Course
Authors: Chen Jiang-Jie , Hsu Yen , Wei Wei , Yang Chun
Published: April 2021

The Basic Design course can help students understand design principles and visual art elements It is a compulsory basic course for the department of art and design in many universities. In recent years, Augmented Reality (AR) technology has found its way into the field of design education and has become a popular textbook tool in teaching courses. There are not many pieces of research on the application of AR in design courses. Therefore, this study attempts to explore the factors that affect students’ acceptance of AR textbooks in Basic Design course and their continuance intention for AR textbooks. This study first focused on students with experience in using AR textbooks. Open-ended questions were used to collect factors that allow AR textbooks to be used in the design curriculum; then questionnaire surveys and factor analysis were conducted and the research hypotheses are presented. Then, the research hypotheses were verified through reliability and validity as well as structural equation modeling. Three factors and 15 items for students to accept AR textbooks in the Basic Design course were summarized in the research results, including the three factors named “Visual Attraction”, “Knowledge-ability”, and “Situational Experience”. The analysis of differences showed significant differences in gender among these three factors and no significant differences between grades and departments. Also, it was found from the analysis results of the structural equation model that the factors of “Visual Attraction” and “Knowledge-ability” both had a positive effect on the continuance intention, of which “Knowledge-ability” was the most important influencing factor. The results of this study can help the application and development of AR textbooks in the Basic Design course.
Efficient CH4/CO2 Gas Mixture Separation through Nanoporous Graphene Membrane Designs
Authors: Razmara Naiyer , Kirch Alexsandro , Meneghini Julio Romano , Miranda Caetano Rodrigues
Published: April 2021

Nanoporous graphene membranes have drawn special attention in the gas-separation processes due to their unique structure and properties. The complexity of the physical understanding of such membrane designs restricts their widespread use for gas-separation applications. In the present study, we strive to propose promising designs to face this technical challenge. In this regard, we investigated the permeation and separation of the mixture of adsorptive gases CO2 and CH4 through a two-stage bilayer sub-nanometer porous graphene membrane design using molecular dynamics simulation. A CH4/CO2 gashouse mixture with 80 mol% CH4 composition was generated using the benchmarked force-fields and was forced to cross through the porous graphene membrane design by a constant piston velocity. Three chambers are considered to be feeding, transferring, and capturing to examine the permeation and separation of molecules under the effect of the two-stage membrane. The main objective is to investigate the multistage membrane and bilayer effect simultaneously. The permeation and separation of the CO2 and CH4 molecules while crossing through the membrane are significantly influenced by the pore offset distance (W) and the interlayer spacing (H) of the bilayer nanoporous graphene membrane. Linear configurations (W = 0 Å) and those with the offset distance of 10 Å and 20 Å were examined by varying the interlayer spacing between 8 Å, 12 Å, and 16 Å. The inline configuration with an interlayer spacing of 12 Å is the most effective design among the examined configurations in terms of optimum separation performance and high CO2 and CH4 permeability. Furthermore, increasing the interlayer distance to 16 Å results in bulk-like behavior rather than membrane-like behavior, indicating the optimum parameters for high selectivity and permeation. Our findings present an appropriate design for the effective separation of CH4/CO2 gas mixtures by testing novel nanoporous graphene configurations.
Anaerobic Co-Digestion of Tannery and Slaughterhouse Wastewater for Solids Reduction and Resource Recovery: Effect of Sulfate Concentration and Inoculum to Substrate Ratio
Authors: Mpofu Ashton B. , Kibangou Victoria A. , Kaira Walusungu M. , Oyekola Oluwaseun O. , Welz Pamela J.
Published: April 2021

Anaerobic digestion is considered unsuitable for the bioremediation of tannery effluent due to process inhibition, mainly due to high concentrations of sulfur species, and the accumulation of H2S and/or NH3. This study using the standardized biochemical methane potential protocol showed that efficient processing is possible with slaughterhouse wastewater, provided sufficient functional biomass is present at the start of the process and the SO42− concentration is below inhibition threshold. Methanogenic activity (K = 13.4–17.5 and µm = 0.15–0.27) and CH4 yields were high when reactors were operated ISR ≥ 3 and/or lower SO42− ≤ 710 mg/L while high SO42− ≥ 1960 mg/L and ISR < 3.0 caused almost complete inhibition regardless of corresponding ISR and SO42−. The theoretical optimum operating conditions (922 mg/L SO42−, ISR = 3.72) are expected to generate 361 mL biogas/gVS, 235 mL CH4/gVS with reduction efficiencies of 27.5% VS, 27.4% TS, 75.1% TOC, 75.6% SO42−, and 41.1% COD. This implies that tannery sludge will be reduced by about 27% (dry mass) and SO42− by 76%, with a fraction of it recovered as S0. The models displayed a perfect fit to the cumulative CH4 yields with high precision in the order Logistic > Cone > modified Gompertz > first order.
Surface Deformations Resulting from Abandoned Mining Excavations
Authors: Strzałkowski Piotr , Ścigała Roman , Szafulera Katarzyna , Kołodziej Konrad
Published: April 2021

The occurrence of surface discontinuous deformations in post-mining areas is currently a significant and important problem, due to both the frequency of their occurrence and the threat they pose to public safety. This paper presents the results of research concerning the possibility of sinkhole formation in the areas of abandoned mining excavations. For the purpose of assessing the condition of the rock mass disturbed by the existence of numerous mining excavations, electrical resistivity tomography investigations were carried out for the selected area where mining was undertaken in the past at shallow depths and many underground workings accessing the deposit exist. The sinkhole hazard was also analysed theoretically with a new original model based on the solution of A. Sałustowicz’s pressure arch theory.
Numerical Assessment and Parametric Optimization of a Piezoelectric Wind Energy Harvester for IoT-Based Applications
Authors: Sheeraz Muhammad Abdullah , Malik Muhammad Sohail , Rehman Khalid , Elahi Hassan , Butt Zubair , Ahmad Iftikhar , Eugeni Marco , Gaudenzi Paolo
Published: April 2021

In the 21st century, researchers have been showing keen interest in the areas of wireless networking and internet of things (IoT) devices. Conventionally, batteries have been used to power these networks; however, due to the limited lifespan of batteries and with the recent advancements in piezoelectric technology, there is a dramatic increase in renewable energy harvesting devices. In this research, an eco-friendly wind energy harvesting device based on the piezoelectric technique is analytically modeled, numerically simulated, and statistically optimized for low power applications. MATLAB toolbox SIMSCAPE is utilized to simulate the proposed wind energy harvester in which a windmill is used to produce rotational motion due to the kinetic energy of wind. The windmill’s rotational shaft is further connected to the rotary to linear converter (RLC) and vibration enhancement mechanism (VEM) for the generation of translational mechanical vibration. Consequently, due to these alternative linear vibrations, the piezoelectric stack produces sufficient electrical output. The output response of the energy harvester is analyzed for the various conditions of piezoelectric thickness, wind speed, rotor angular velocity, and VEM stiffness. It is observed that the electrical power of the proposed harvester is proportional to the cube of wind speed and is inversely proportional to the number of rotor blades. Furthermore, an optimization strategy based on the full factorial design of the experiment is developed and implemented on MINITAB 18.0 for evaluating the statistical performance of the proposed harvester. It is noticed that a design with 3 rotor-blades, having 3 mm piezoelectric thickness, and 40 Nm−1 stiffness generates the optimum electrical response of the harvester.
A Gate-to-Gate Life Cycle Assessment for the CO2-EOR Operations at Farnsworth Unit (FWU)
Authors: Morgan Anthony , Grigg Reid , Ampomah William
Published: April 2021

Greenhouse gas (GHG) emissions related to the Farnsworth Unit’s (FWU) carbon dioxide enhanced oil recovery (CO2-EOR) operations were accounted for through a gate-to-gate life cycle assessment (LCA) for a period of about 10 years, since start of injection to 2020, and predictions of 18 additional years of the CO2-EOR operation were made. The CO2 source for the FWU project has been 100% anthropogenically derived from the exhaust of an ethanol plant and a fertilizer plant. A cumulative amount of 5.25 × 106 tonnes of oil has been recovered through the injection of 1.64 × 106 tonnes of purchased CO2, of which 92% was stored during the 10-year period. An LCA analysis conducted on the various unit emissions of the FWU process yielded a net negative (positive storage) of 1.31 × 106 tonnes of CO2 equivalent, representing 79% of purchased CO2. An optimized 18-year forecasted analysis estimated 86% storage of the forecasted 3.21 × 106 tonnes of purchased CO2 with an equivalent 2.90 × 106 tonnes of crude oil produced by 2038. Major contributors to emissions were flaring/venting and energy usage for equipment. Improvements on the energy efficiency of equipment would reduce emissions further but this could be challenging. Improvement of injection capacity and elimination of venting/flaring or fugitive gas are methods more likely to be utilized for reducing net emissions and are the cases used for the optimized scenario in this work. This LCA illustrated the potential for the CO2-EOR operations in the FWU to store more CO2 with minimal emissions.
A CFD-Based Comparison of Different Positive Displacement Pumps for Application in Future Automatic Transmission Systems
Authors: Lobsinger Thomas , Hieronymus Timm , Schwarze Hubert , Brenner Gunther
Published: April 2021

The efficiency requirements for hydraulic pumps applied in automatic transmissions in future generations of automobiles will increase continuously. In addition, the pumps must be able to cope with multiphase flows to a certain extent. Given this background, a balanced vane pump (BVP), an internal gear pump (IGP) and a three-dimensional geared tumbling multi chamber (TMC) pump are analyzed and compared by a computational fluid dynamics (CFD) approach with ANSYS CFX and TwinMesh. Furthermore, test bench measurements are conducted to obtain experimental data to validate the numerical results. The obtained numerical results show a reasonable agreement with the experimental data. In the first CFD setup, the conveying characteristics of the pumps with pure oil regarding volumetric efficiencies, cavitation onset and pressure ripple are compared. Both the IGP and the BVP show high volumetric efficiencies and low pressure ripples whereas the TMC shows a weaker performance regarding these objectives. In the second CFD setup, an oil-bubbly air multiphase flow with different inlet volume fractions (IGVF) is investigated. It can be shown that free air changes the pumping characteristics significantly by increasing pressure and mass flow ripple and diminishing the volumetric efficiency as well as the required driving torque. The compression ratios of the pumps appear to be an important parameter that determines how the multiphase flow is handled regarding pressure and mass flow ripple. Overall, the BVP and the IGP show both a similar strong performance with and without free air. In the current development state, the TMC pump shows an inferior performance because of its lower compression ratio and therefore needs further optimization.
How Smart Meter Data Analysis Can Support Understanding the Impact of Occupant Behavior on Building Energy Performance: A Comprehensive Review
Authors: Adams Jacqueline Nicole , Bélafi Zsófia Deme , Horváth Miklós , Kocsis János Balázs , Csoknyai Tamás
Published: April 2021

The goal of this literature review was to outline the research currently conducted on smart meter (SM) adoption and its connection to building occupant behavior to better understand both SM technology and SM customers. We compiled our findings from the existing literature and developed a holistic understanding of the socio-demographic factors that lead to more or less energy use, the methods used to group and cluster occupants on the basis of energy use, how occupant energy use profiles are developed, and which socio-psychological determinants may influence SM adoption. Our results highlight 11 demographic variables that impact building energy use, find 9 methods commonly used to profile occupants on the basis of energy usage, and highlight 13 socio-psychological variables than can be utilized to better understand SM adoption intentions. The review findings two major deficiencies in the existing literature. First, this review highlights the lack of existing interdisciplinary research that combines occupant behavior with SM data and a clear socio-psychological framework. Second, this review underscores certain data limitations in existing SM research, with most research being conducted only on residential or office buildings and geographically in North America or Western Europe. Final policy recommendations center on increased need for interdisciplinary SM research and the need for an expanded understanding of occupant behavior and SM research across different geographies.
Economic Analysis of the Investments in Battery Energy Storage Systems: Review and Current Perspectives
Authors: Rotella Junior Paulo , Rocha Luiz Célio Souza , Morioka Sandra Naomi , Bolis Ivan , Chicco Gianfranco , Mazza Andrea , Janda Karel
Published: April 2021

Sources such as solar and wind energy are intermittent, and this is seen as a barrier to their wide utilization. The increasing grid integration of intermittent renewable energy sources generation significantly changes the scenario of distribution grid operations. Such operational challenges are minimized by the incorporation of the energy storage system, which plays an important role in improving the stability and the reliability of the grid. This study provides the review of the state-of-the-art in the literature on the economic analysis of battery energy storage systems. The paper makes evident the growing interest of batteries as energy storage systems to improve techno-economic viability of renewable energy systems; provides a comprehensive overview of key methodological possibilities for researchers interested in economic analysis of battery energy storage systems; indicates the need to use adequate economic indicators for investment decisions; and identifies key research topics of the analyzed literature: (i) photovoltaic systems with battery energy storage systems for residential areas, (ii) comparison between energy storage technologies, (iii) power quality improvement. The last key contribution is the proposed research agenda.
A Multilayer Brushless DC Motor for Heavy Lift Drones
Authors: Carev Vadim , Roháč Jan , Šipoš Martin , Schmirler Michal
Published: April 2021

This paper describes the concept of a multilayer brushless DC motor which is suitable for use on unmanned aerial vehicles (UAVs) and capable of carrying a heavy payload. The paper deals with a unique multilayer structure, using three standard stators placed in parallel with a single rotor body, to increase the torque even under low-speed conditions. In this solution, nine inner windings can use different star/delta interconnections to optimize the performance of the BLDC motor on demand. The proposed multilayer BLDC motor solution utilizes the main advantages of BLDC motors, ensuring highly reliable operation, and thus enabling a BLDC motor to be applied to UAVs. This paper gives an overview of the design, assumes an extension with an electronic inner winding switching capability, and provides practical details about realization, testing, and experimental verification. Practical measurements and obtained data are utilized to confirm the approach.
Design of All-Small-Molecule Organic Solar Cells Approaching 14% Efficiency via Isometric Terminal Alkyl Chain Engineering
Authors: Chen Haiyan , Tang Hua , Hu Dingqin , Xiao Yiqun , Fu Jiehao , Lv Jie , Yu Qingqing , Xiao Zeyun , Lu Xinhui , Hu Hanlin , Lu Shirong
Published: April 2021

Morphology is crucial to determining the photovoltaic performance of organic solar cells (OSCs). However, manipulating morphology involving only small-molecule donors and acceptors is extremely challenging. Herein, a simple terminal alkyl chain engineering process is introduced to fine-tune the morphology towards high-performance all-small-molecule (ASM) OSCs. We successfully chose a chlorinated two-dimension benzo[1,2-b:4,5-b′]dithiophene (BDT) central unit and two isomeric alkyl cyanoacetate as the end-capped moieties to conveniently synthesize two isomeric small-molecule donors, namely, BT-RO-Cl and BT-REH-Cl, each bearing linear n-octyl (O) as the terminal alkyl chain and another branched 2-ethylhexyl (EH) as the terminal alkyl chain. The terminal alkyl chain engineering process provided BT-RO-Cl with 13.35% efficiency and BT-REH-Cl with 13.90% efficiency ASM OSCs, both with Y6 as the electron acceptor. The successful performance resulted from uniform phase separation and the favorable combination of face-on and edge-on molecular stacking of blended small-molecule donors and acceptors, which formed a fluent 3D transport channel and thus delivered high and balanced carrier mobilities. These findings demonstrate that alkyl chain engineering can finely control the morphology of ASM OSCs, and provides an alternative for the optimal design of small-molecule materials towards high-performance ASM OSCs.
Image Preprocessing for Outdoor Luminescence Inspection of Large Photovoltaic Parks
Authors: Kölblin Pascal , Bartler Alexander , Füller Marvin
Published: April 2021

Electroluminescence (EL) measurements allow one to detect damages and/or defective parts in photovoltaic systems. In principle, it seems possible to predict the complete current/voltage curve from such pictures even automatically. However, such a precise analysis requires image corrections and calibrations, because vignetting and lens distortion cause signal and spatial distortions. Earlier works on crystalline silicon modules used the cell gap joints (CGJ) as calibration pattern. Unfortunately, this procedure fails if the detection of the gaps is not accurate or if the contrast in the images is low. Here, we enhance the automated camera calibration algorithm with a reliable pattern detection and analyze quantitatively the quality of the process. Our method uses an iterative Hough transform to detect line structures and uses three key figures (KF) to separate detected busbars from cell gaps. This method allows a reliable identification of all cell gaps, even in noisy images or if disconnected edges in PV cells exist or potential induced degradation leads to a low contrast between active cell area and background. In our dataset, a subset of 30 EL images (72 cell each) forming grid (5×11) lead to consistent calibration results. We apply the calibration process to 997 single module EL images of PV modules and evaluate our results with a random subset of 40 images. After lens distortion correction and perspective correction, we analyze the residual deviation between ideal target grid points and the previously detected CGJ after applied distortion and perspective correction. For all of the 2200 control points in the 40 evaluation images, we achieve a deviation of less than or equal to 3 pixels. For 50% of the control points, a deviation of of less than or equal to 1 pixel is reached.
SWIPT-Assisted Energy Efficiency Optimization in 5G/B5G Cooperative IoT Network
Authors: Amjad Maliha , Chughtai Omer , Naeem Muhammad , Ejaz Waleed
Published: April 2021

Resource use in point-to-point and point-to-multipoint communication emerges with the tremendous growth in wireless communication technologies. One of the technologies is wireless power transfer which may be used to provide sufficient resources for energy-constrained networks. With the implication of cooperative communication in 5G/B5G and the Internet of Things (IoT), simultaneous wireless information and power transfer (SWIPT)-assisted energy efficiency and appropriate resource use become challenging tasks. In this paper, multiple IoT-enabled devices are deployed to cooperate with the source node through intermediate/relay nodes powered by radio-frequency (RF) energy. The relay forwards the desired information generated by the source node to the IoT devices with the fusion of decode/amplify processes and charges itself at the same time through energy harvesting technology. In this regard, a problem with throughput, energy efficiency, and joint throughput with user admission maximization is formulated while assuring the useful, practical network constraints, which contemplate the upper/lower bounds of power transmitted by the source node, channel condition, and energy harvesting. The formulated problem is a mixed-integer non-linear problem (MINLP). To solve the formulated problem, the rate of individual IoT-enabled devices (b/s), number of selected IoT devices, and the sum-rate maximization are prosecuted for no-cooperation, cooperation with diversity, and cooperation without diversity. Moreover, a comparison of the outer approximation algorithm (OAA) and mesh adaptive direct search algorithm (MADS) for non-linear optimization with the exhaustive search algorithm is provided. The results with reference to the complexity of the algorithms have also been evaluated which show that 4.68×10−10 OAA and 7.81×10−11 MADS as a percent of ESA, respectively. Numerous simulations are carried out to exhibit the usefulness of the analysis to achieve the convergence to ε-optimal solution.
Life Cycle Perspectives of Using Non-Pelleted vs. Pelleted Corn Stover in a Cellulosic Biorefinery
Authors: Nahar Nurun , Pandey Ramsharan , Pourhashem Ghasideh , Ripplinger David , Pryor Scott W.
Published: April 2021

Cellulosic biorefineries have attracted interest due to the growing energy security and environmental concerns related to fossil fuel-based energy and chemicals. Using pelleted biomass as a biorefinery feedstock can reduce their processing inputs while improving biomass handling and transportation. However, it is still questionable whether energy and emission savings from feedstock transportation and processing can justify pelletization. A life cycle assessment approach was used to compare energy consumption and greenhouse gas (GHG) emissions from pelleted and non-pelleted corn stover as a biorefinery feedstock. Operations considered were pelleting, transportation, and soaking in aqueous ammonia (SAA) pretreatment. Despite greater GHG emissions (up to 25 times higher than the transportation) generated from the pelleting process, the model showed a significant opportunity to offset and even reduce overall GHG emissions considering the pretreatment process benefits. Our process energy analysis showed that SAA pretreatment of pelleted biomass required significantly lower energy inputs (56%) due to the lower-severity pretreatment’s effectiveness. Higher pretreatment solid loadings are allowed when pelleted biomass is used and this reduces the process chemicals and water requirements by 56% and 49%, respectively. This study demonstrated that the SAA pretreatment of pelleted biomass might be a feasible option as the cellulosic biorefinery feedstock.
Co-Combustion of Biomass with Coal in Grate Water Boilers at Low Load Boiler Operation
Authors: Nowak Krzysztof , Rabczak Sławomir
Published: April 2021

Environmental protection, and in particular air protection against pollution, is an extremely important element of the global policy of many countries. The problem of air pollution is particularly important in Poland, where the heating market is one of the largest in Europe and is based in 74% on the use of fossil fuels, in particular hard coal. One of the technological solutions for the implementation of cleaner fuels is the co-combustion of coal and biomass. This process enables the reduction of harmful pollutants such as CO2, SO2, and can be implemented in existing boilers. Heating boilers achieve the highest design efficiency during optimal load at the level of 85–95% of nominal power. Under such conditions, heat production is most efficient. During operation, boilers are often started, extinguished or run below rated output, resulting in increased emissions. This publication presents the results of measurements of efficiency and concentrations of pollutants in the WR water boiler during operation below the technical minimum. Hard coal was cofired in the boiler with biomass of wood origin. It was noted that the amount of biomass had a significant impact on the boiler efficiency and pollutant emission. Based on the research, it was also noted that it was possible to make a qualitative prediction of these parameters. The obtained results are an introduction to a deeper analysis and further research on the correlation between the amount of biomass and boiler power and the efficiency and concentration of pollutants.
Combustion Modes and Unsteady Characteristics during the Condition Transition of a Scramjet Combustor
Authors: Jia Dongpeng , Pan Yu , Wang Ning , Liu Chaoyang , Yang Kai
Published: April 2021

To investigate the combustion modes and unsteady characteristics during the condition transition of a scramjet combustor, a series of experiments were carried out under the condition of Mach 2.52 supersonic incoming flow, the corresponding stagnation pressure and temperature of which were 1.6 MPa and 1486 K, respectively. A fuel supply system that could dynamically adjust the injection pressure was adopted to simulate the condition transition stage of a scramjet. Based on the advanced combustion diagnosis technique, the transient chemiluminescence image and the wall pressure were recorded during the whole combustion process. Three typical modes of turbulent combustion occurred when the injection pressure drop gradually increased. The jet flame was stable after the condition transition when the injection pressure drop was relatively low. An unstable combustion phenomenon accompanied by intermittent local extinction and reignition could be found near the blowout limits. With a further increase in the injection pressure drop, the flame was blown out quickly during the transition process. In addition, the flame development characteristics during condition transition under stable combustion mode and the effect of injection pressure drop were studied in detail. During the process of switching between the two conditions, the area and light intensity of the flame decreased over time, and the wall pressure was accordingly reduced. As the increase in injection pressure dropped, the intensity of chemical reactions deceased obviously and the transition time became longer.