bluuebunny/crossref_metadata_2025 huggingface dataset:
Wafer-Scale Fabrication of Silicon Film on Lithium Niobate on Insulator (LNOI)
Authors: Chen Yang , Zhao Xiaomeng , Li Zhongxu , Ke Xinjian , Wang Chengli , Zhou Min , Li Wenqin , Huang Kai , Ou Xin
Published: October 2022

Hybrid integration of silicon photonics with lithium niobate (LN) devices provides a promising route to enable an excellent modulation performance in silicon photonic integrated circuits. To realize this purpose, a substrate containing a Si film on an LNOI substrate, called Si on the LNOI structure, was analyzed and fabricated. The mode propagation properties in the Si-on-LNOI structure were simulated in detail and a vertical adiabatic coupler (VAC) between the Si waveguide and LN waveguide was simulated to help in the determination of the dimension of this structure. A 4-inch wafer-scale Si on an LNOI hybrid structure was fabricated through the ion-cut process. This structure has a single-crystalline quality, high thickness uniformity, smooth surface, and sharp bonding interface, which are practical for realizing low loss and high coupling efficiency.
Pemigatinib in Intrahepatic Cholangiocarcinoma: A Work in Progress
Authors: Gadaleta-Caldarola Gennaro , Rizzo Alessandro , Dadduzio Vincenzo , Lombardi Lucia , Gadaleta-Caldarola Arianna , Infusino Stefania , Cusmai Antonio , Citrigno Claudia , Palmiotti Gennaro
Published: October 2022

Cholangiocarcinoma (CCA) is the second most frequent primary liver cancer, following hepatocellular carcinoma (HCC). Progress in the molecular understanding of CCA has led to the development of several agents, including FGFR inhibitors, such as pemigatinib, whose approval has marked a new era in this hepatobiliary malignancy. However, a number of questions remain unanswered, including the development of secondary resistance and the role of combination therapies, including FGFR inhibitors. Herein, we specifically focus on the current challenges and future research directions of pemigatinib use in CCA patients.
Meet Me Halfway: Will Photoperiodic Responses of Interpopulation Hybrids of the Brown Marmorated Stink Bug Halyomorpha halys (Hemiptera: Heteroptera: Pentatomidae) Promote or Constrain Subsequent Invasions?
Authors: Reznik Sergey Ya. , Karpun Natalia N. , Dolgovskaya Margarita Yu. , Saulich Aida Kh. , Musolin Dmitry L.
Published: October 2022

Biological invasions often result from multiple invasion events. In the case of several subsequent invasive episodes, ‘newcomers’ are usually poorly adapted to local environmental conditions in contrast to the representatives of the already-established invasive population of the same species. Therefore, the mode of inheritance of life-history features determining the survival and performance of interpopulation hybrids is an important component of invasiveness. We investigated the mode of inheritance of the photoperiodic response in the brown marmorated stink bug, Halyomorpha halys, by crossing between the native population of South Korea and the invasive population of the Black Sea coast of Russia. The aim of this study was to predict the overwintering potential of the progeny from possible crosses between representatives of the native and invasive populations. The pre-adult development time and the incidence of winter adult diapause in the progeny of the interpopulation crosses were close to the average of the values recorded in ‘pure’ (unmixed) crosses. Female and male genotypes were equally important in the determination of these characters. Such a mode of inheritance is most likely determined by a polygenic control and would only partially promote subsequent invasion events from the native South Asian range of H. halys into Europe.
Acanthosis Nigricans: Pointer of Endocrine Entities
Authors: Radu Andreea-Maria , Carsote Mara , Dumitrascu Mihai Cristian , Sandru Florica
Published: October 2022

Acanthosis nigricans (AN) has been reported in relation to insulin resistance (IR). We aim to review AN through an endocrine and metabolic perspective focusing on IR in association with metabolic complications such as obesity, diabetes mellitus (DM), and metabolic syndrome (MS) with/without polycystic ovary syndrome (PCOS). We revised English papers on PubMed covering publications from the last 5 years. The current prevalence of AN varies from 4.5 to 74% (or even 100%, depending on the studied population), with equal distribution among females and males. Despite higher incidence with an age-dependent pattern, an alarming escalation of cases has been noted for obesity and MS in younger populations. Most frequent IR-associated sites are the neck, axilla, and knuckles, but unusual locations such as the face have also been reported. Quantitative scales such as Burke have been used to describe the severity of the dermatosis, particularly in correlation with IR elements. Dermoscopic examination are required, for instance, in cases with sulcus cutis, hyperpigmented spots, crista cutis, and papillary projections. A skin biopsy may be necessary, but it is not the rule. Both IR that clinically manifests with or without obesity/MS correlates with AN; most studies are cross-sectional, with only a few longitudinal. The approach varied from screening during school periodic checkups/protocols/programs to subgroups of individuals who were already known to be at high cardio-metabolic risk. AN was associated with type2DM, as well as type 1DM. Females with PCOS may already display metabolic complications in 60–80% of cases, with AN belonging to the associated skin spectrum. AN management depends on underlying conditions, and specific dermatological therapy is not generally required, unless the patient achieves metabolic control, has severe skin lesions, or desires cosmetic improvement. In IR cases, lifestyle interventions can help, including weight control up to bariatric surgery. In addition, metformin is a key player in the field of oral medication against DM type 2, a drug whose indication is extended to PCOS and even to AN itself, outside the specific panel of glucose anomalies. In terms of cosmetic intervention, limited data have been published on melatonin, urea cream, topical retinoids, vitamin D analogs, or alexandrite laser. In conclusion, awareness of IR and its associated clinical features is essential to provide prompt recognition of underlying conditions. AN represents a useful non-invasive surrogate marker of this spectrum in both children and adults. The pivotal role of this dermatosis could massively improve endocrine and metabolic assessments.
Novel Ex Vivo DOAC Removal Methods Reduce Interference in Lupus Anticoagulant Testing
Authors: Savola Paula , Lemponen Marja , Joutsi-Korhonen Lotta , Helin Tuukka A.
Published: October 2022

Direct oral anticoagulants (DOAC) interfere in laboratory coagulation testing. The aim here was to study how commercial DOAC removal methods, DOAC Filter® and DOAC-Stop™, perform to eliminate DOAC concentrations and false positive results in lupus anticoagulant (LAC) testing. We acquired 50 patient samples with high concentrations of DOACs: apixaban (n = 18, range 68–572 ng/mL), dabigatran (n = 8, range 47–154 ng/mL), edoxaban (n = 8, range 35–580 ng/mL) and rivaroxaban (n = 16, range 69–285 ng/mL). DOACs were removed ex vivo with either DOAC Filter® (n = 28) or DOAC-Stop™ (n = 22). Additionally, commercial control and calibrator samples were studied (n = 13 for DOAC Filter®, n = 14 for DOAC-Stop™). LAC screening was performed before and after DOAC removal. Both DOAC Filter® and DOAC-Stop™ were effective in removing DOAC concentrations in samples: DOAC concentrations decreased to median of 0 ng/mL (range 0–48 ng/mL). Only one sample had more than residual 25 ng/mL of DOAC (apixaban). Before DOAC removal, 96% (48/50) of patient samples and over 90% (12/13 DOAC Filter®, 13/14 DOAC-Stop™) of control/calibrator samples were positive in the LAC screening. In patient samples, LAC screening turned negative in 61% (17/28) after DOAC Filter® and 45% (10/22) after DOAC-Stop™ treatment. All control samples became negative after DOAC removal. In conclusion, DOAC removal ex vivo reduces false positives in LAC screening. DOAC removal halved the need for confirmation or mixing tests- Although a subset of patients would require further testing, DOAC removal reduces unnecessary repeated LAC testing.
Two Gingival Cell Lines Response to Different Dental Implant Abutment Materials: An In Vitro Study
Authors: Osman Muataz A. , Kushnerev Evgeny , Alamoush Rasha A. , Seymour Kevin. G. , Yates Julian M.
Published: October 2022

Objectives: This study aimed to investigate the response of human gingival fibroblasts (HGFB) and human gingival keratinocytes (HGKC) towards different dental implant abutment materials. Methods: Five materials were investigated: (1) titanium (Ti), (2) titanium nitride (TiN), (3) cobalt-chromium (CoCr), (4) zirconia (ZrO2), and (5) modified polyether ether ketone (m-PEEK). Both cell lines were cultured, expanded, and seeded in accordance with the protocol of their supplier. Cell proliferation and cytotoxicity were evaluated at days 1, 3, 5, and 10 using colourimetric viability and cytotoxicity assays. Data were analysed via two-way ANOVA, one-way ANOVA, and Tukey’s post hoc test (p < 0.05 for all tests). Results: There was a statistically significant difference in cell proliferation of HGKC and HGFB cells in contact with different abutment materials at different time points, with no significant interaction between different materials. There was a significant effect on cell proliferation and cytotoxicity with different exposure times (p < 0.0001) for each material. Cell proliferation rates were comparable for both cell lines at the beginning of the study, however, HGFB showed higher proliferation rates for all materials at day 10 with better proliferation activities with ZrO and m-PEEK (40.27%) and (48.38%) respectively. HGKC showed significant interactions (p < 0.0001) in cytotoxicity between different materials. Conclusion: The present in vitro assessment investigated the biocompatibility of different abutment materials with soft tissue cells (HGFB and HGKC). The findings suggest that m-PEEK and TiN are biologically compatible materials with human cells that represent the soft tissue and can be considered as alternative implant abutment materials to Ti and ZrO2, especially when the aesthetic is of concern.
Probabilistic Pairwise Model Comparisons Based on Bootstrap Estimators of the Kullback–Leibler Discrepancy
Authors: Dajles Andres , Cavanaugh Joseph
Published: October 2022

When choosing between two candidate models, classical hypothesis testing presents two main limitations: first, the models being tested have to be nested, and second, one of the candidate models must subsume the structure of the true data-generating model. Discrepancy measures have been used as an alternative method to select models without the need to rely upon the aforementioned assumptions. In this paper, we utilize a bootstrap approximation of the Kullback–Leibler discrepancy (BD) to estimate the probability that the fitted null model is closer to the underlying generating model than the fitted alternative model. We propose correcting for the bias of the BD estimator either by adding a bootstrap-based correction or by adding the number of parameters in the candidate model. We exemplify the effect of these corrections on the estimator of the discrepancy probability and explore their behavior in different model comparison settings.
Flows of Substances in Networks and Network Channels: Selected Results and Applications
Authors: Dimitrova Zlatinka
Published: October 2022

This review paper is devoted to a brief overview of results and models concerning flows in networks and channels of networks. First of all, we conduct a survey of the literature in several areas of research connected to these flows. Then, we mention certain basic mathematical models of flows in networks that are based on differential equations. We give special attention to several models for flows of substances in channels of networks. For stationary cases of these flows, we present probability distributions connected to the substance in the nodes of the channel for two basic models: the model of a channel with many arms modeled by differential equations and the model of a simple channel with flows of substances modeled by difference equations. The probability distributions obtained contain as specific cases any probability distribution of a discrete random variable that takes values of 0,1,…. We also mention applications of the considered models, such as applications for modeling migration flows. Special attention is given to the connection of the theory of stationary flows in channels of networks and the theory of the growth of random networks.
A Hyper-Chaotically Encrypted Robust Digital Image Watermarking Method with Large Capacity Using Compress Sensing on a Hybrid Domain
Authors: Yang Zhen , Sun Qingwei , Qi Yunliang , Li Shouliang , Ren Fengyuan
Published: October 2022

The digital watermarking technique is a quite promising technique for both image copyright protection and secure transmission. However, many existing techniques are not as one might have expected for robustness and capacity simultaneously. In this paper, we propose a robust semi-blind image watermarking scheme with a high capacity. Firstly, we perform a discrete wavelet transformation (DWT) transformation on the carrier image. Then, the watermark images are compressed via a compressive sampling technique for saving storage space. Thirdly, a Combination of One and Two-Dimensional Chaotic Map based on the Tent and Logistic map (TL-COTDCM) is used to scramble the compressed watermark image with high security and dramatically reduce the false positive problem (FPP). Finally, a singular value decomposition (SVD) component is used to embed into the decomposed carrier image to finish the embedding process. With this scheme, eight 256×256 grayscale watermark images are perfectly embedded into a 512×512 carrier image, the capacity of which is eight times over that of the existing watermark techniques on average. The scheme has been tested through several common attacks on high strength, and the experiment results show the superiority of our method via the two most used evaluation indicators, normalized correlation coefficient (NCC) values and the peak signal-to-noise ratio (PSNR). Our method outperforms the state-of-the-art in the aspects of robustness, security, and capacity of digital watermarking, which exhibits great potential in multimedia application in the immediate future.
Predicting Bitcoin (BTC) Price in the Context of Economic Theories: A Machine Learning Approach
Authors: Erfanian Sahar , Zhou Yewang , Razzaq Amar , Abbas Azhar , Safeer Asif Ali , Li Teng
Published: October 2022

Bitcoin (BTC)—the first cryptocurrency—is a decentralized network used to make private, anonymous, peer-to-peer transactions worldwide, yet there are numerous issues in its pricing due to its arbitrary nature, thus limiting its use due to skepticism among businesses and households. However, there is a vast scope of machine learning approaches to predict future prices precisely. One of the major problems with previous research on BTC price predictions is that they are primarily empirical research lacking sufficient analytical support to back up the claims. Therefore, this study aims to solve the BTC price prediction problem in the context of both macroeconomic and microeconomic theories by applying new machine learning methods. Previous work, however, shows mixed evidence of the superiority of machine learning over statistical analysis and vice versa, so more research is needed. This paper applies comparative approaches, including ordinary least squares (OLS), Ensemble learning, support vector regression (SVR), and multilayer perceptron (MLP), to investigate whether the macroeconomic, microeconomic, technical, and blockchain indicators based on economic theories predict the BTC price or not. The findings point out that some technical indicators are significant short-run BTC price predictors, thus confirming the validity of technical analysis. Moreover, macroeconomic and blockchain indicators are found to be significant long-term predictors, implying that supply, demand, and cost-based pricing theories are the underlying theories of BTC price prediction. Likewise, SVR is found to be superior to other machine learning and traditional models. This research’s innovation is looking at BTC price prediction through theoretical aspects. The overall findings show that SVR is superior to other machine learning models and traditional models. This paper has several contributions. It can contribute to international finance to be used as a reference for setting asset pricing and improved investment decision-making. It also contributes to the economics of BTC price prediction by introducing its theoretical background. Moreover, as the authors still doubt whether machine learning can beat the traditional methods in BTC price prediction, this research contributes to machine learning configuration and helping developers use it as a benchmark.
Template Attack of LWE/LWR-Based Schemes with Cyclic Message Rotation
Authors: Chang Yajing , Yan Yingjian , Zhu Chunsheng , Guo Pengfei
Published: October 2022

The side-channel security of lattice-based post-quantum cryptography has gained extensive attention since the standardization of post-quantum cryptography. Based on the leakage mechanism in the decapsulation stage of LWE/LWR-based post-quantum cryptography, a message recovery method, with templates and cyclic message rotation targeting the message decoding operation, was proposed. The templates were constructed for the intermediate state based on the Hamming weight model and cyclic message rotation was used to construct special ciphertexts. Using the power leakage during operation, secret messages in the LWE/LWR-based schemes were recovered. The proposed method was verified on CRYSTAL-Kyber. The experimental results demonstrated that this method could successfully recover the secret messages used in the encapsulation stage, thereby recovering the shared key. Compared with existing methods, the power traces required for templates and attack were both reduced. The success rate was significantly increased under the low SNR, indicating a better performance with lower recovery cost. The message recovery success rate could reach 99.6% with sufficient SNR.
Home Range, Movement and Activity Patterns of Six vulture Species Using Satellite Telemetry in Saurashtra landscape, Gujarat, India
Authors: Ram Mohan , Sahu Aradhana , Tikadar Shyamal , Gadhavi Devesh , Rather Tahir Ali , Jhala Lahar , Zala Yashpal
Published: October 2022

The information on the ranging behaviour and migration pattern of vultures is of critical conservation importance. Vultures’ range over vast areas in human-dominated landscapes where anthropogenic activities may influence their long-term survival. This paper uses the satellite telemetry of 11 individuals of six vulture species to assess their home ranges and seasonal movement patterns. The study aimed to find daily and monthly distances covered by vultures, their home range size, and the influence of breeding season on resource utilisation and activity rates. A total of 114,820 locations were collected between October 2020 and November 2021. The results indicate that the size of the core area is smaller during the breeding season of the resident species, such as the Indian vulture (Gyps indicus), white-rumped vulture (Gyps bengalensis), and red-headed vulture (Sarcogyps calvus) than the non-breeding season. vulture’s daily and monthly movement (mean) also decreased in the breeding season. The annual home range and core areas, calculated as 95% and 50%Utilisation Distribution differed between breeding and non-breeding seasons. The migratory vultures moved significantly longer distances across days and months than the resident species. Their annual migration patterns also differed with respect to time and migration routes.
Intention to Use E-Payments from the Perspective of the Unified Theory of Acceptance and Use of Technology (UTAUT): Evidence from Yemen
Authors: Alduais Fahd , Al-Smadi Mohammad O.
Published: October 2022

This study explores the challenges facing the current e-payment systems and investigates the main factors that support using the e-payment system. This study used a cross-sectional approach. An online survey was conducted on Yemeni consumers as part of the collection of data. The data from 486 questionnaires were analyzed using smartPLS4 and Jamovi software for structural model analysis and statistical analysis. According to the PLS-SEM results, the structural model shows that R2 is 0.757, which explains the variances in behavioral intention via all the constructs. Statistically, the intention to use e-payment systems is significantly and positively influenced by performance and effort expectancies and social influence. In contrast, facilitation conditions are significantly and negatively correlated with behavioral intention. This is attributed to consumers’ view of the infrastructure of Internet services, which does not contribute to the behavioral intention and acceptance of using electronic payment in Yemen. Contrary to expectations, age does not moderate the relationship between performance expectancy, social influence, and intention to use e-payment systems; hence, the related hypothesis was not supported. This study provides valuable suggestions for policymakers, designers, developers, and researchers, enabling them to better understand the critical aspects of using the electronic payment system. This study developed a model for predicting the likelihood of acceptance of electronic payments in a country that has not given adequate attention to this issue. An application and evaluation of the UTAUT model in Yemen are presented in this study.
Collaborative Crowdsourced Software Testing
Authors: Alyahya Sultan
Published: October 2022

Crowdsourced software testing (CST) uses a crowd of testers to conduct software testing. Currently, the microtasking model is used in CST; in it, a testing task is sent to individual testers who work separately from each other. Several studies mentioned that the quality of test reports produced by individuals was a drawback because a large number of invalid defects were submitted. Additionally, individual workers tended to catch the simple defects, not those with high complexity. This research explored the effect of having pairs of collaborating testers working together to produce one final test report. We conducted an experiment with 75 workers to measure the effect of this approach in terms of (1) the total number of unique valid defects detected, (2) the total number of invalid defects reported, and (3) the possibility of detecting more difficult defects. The findings show that testers who worked in collaborating pairs can be as effective in detecting defects as an individual worker; the differences between them are marginal. However, CST significantly affects the quality of test reports submitted in two dimensions: it helps reduce the number of invalid defects and also helps detect more difficult defects. The findings are promising and suggest that CST platforms can benefit from new mechanisms that allow for the formation of teams of two individuals who can participate in doing testing jobs.
Expected Area-Based Real-Time Routing Protocol for Supporting Mobile Sinks in Wireless Sensor Networks
Authors: Nam Youngju , Choi Hyunseok , Shin Yongje , Park Soochang , Lee Euisin
Published: October 2022

To deliver real-time data within a desired time deadline, a spatiotemporal approach has been proposed in wireless sensor networks. In the approach, real-time data can be delivered with a delivery speed calculated by both the distance from a source to a static sink and the desired time deadline. In the case of a mobile sink, because the distance from a source to the sink would be dynamically changed due to its movement, real-time data cannot be delivered due to the inability to calculate a delivery speed. Thus, we propose a novel real-time routing protocol, called EAR2 (expected area-based real-time routing) for mobile sinks. Instead of the immediate distance, EAR2 considers the static distance to the expected area of a mobile sink’s location using its movement speed. To satisfy the desired time deadline, EAR2 guarantees that the total summation of the unicasting time to the expected area and the flooding time within the expected area can be smaller than the deadline. To do this, EAR2 calculates a data delivery speed by using the static distance and the unicasting time and exploits the flooding time observed from various network environments. Because EAR2 has a high flooding time and data loss problems due to a single flooding point, we propose a protocol called EAR2M with multiple flooding points, which reduces the flooding time and enhances the reliability of data transmission. We also propose two extensions of EAR2M, called EAR2M_R and EAR2M_E for efficient data transmission from a source to multiple flooding points. They aim to reduce the transmission delay and the energy consumption for efficient data transmission among multiple flooding points, respectively. Simulation results show that EAR2 improves the deadline miss ratio and the energy consumption, with averages improvements of 47.17% and 29.99% over the existing schemes, respectively. Furthermore, EAR2M with four flooding points enhances the deadline miss ratio and the energy consumption by an average of 12.69% and 131.86% over EAR2.
Temperature–Magnetic Field Dual-Parameter Sensor Based on Circular Lattice Photonic Crystal Fiber
Authors: Wang Daobin , Huang Quansheng , Yang Jiahuan , Yuan Lihua
Published: October 2022

This paper proposed and investigated a sensor that could simultaneously measure temperature and magnetic fields. The key component of this sensor was a photonic crystal fiber with a length of only 1 cm, whose air holes were arranged in a circular lattice symmetry. In order to increase the birefringence of the fiber, we introduced well-designed point defects into the photonic lattice. The deficient pores were filled with a magneto-fluidic material (MF) that sensed temperature and magnetic fields through changes in its refractive index. The outer layer of the fiber cladding was coated with a thin film of Indium tin oxide (ITO), which was in direct contact with ethanol. The surface plasmon resonance created by ITO was used to achieve dual-parameter demodulation and solve the cross-sensitivity problem. The photonic crystal fiber and other optical components made up a Sagnac interferometer, which was used to measure the transmission spectrum of the Sagnac interference. At the same time, the loss spectrum due to the surface plasmon resonance was measured. The variation in temperature and magnetic field was directly related to the shift in the resonance wavelengths of the transmission and loss spectra, thus enabling simultaneous dual-parameter measurements. We investigated the sensing performance of the sensor numerically. The results showed a wavelength sensitivity of 7.6 nm/°C and 0.75 nm/mT, with a resolution of 1.316 × 10−3 °C and 1.333 × 10−3 mT for temperature and magnetic field, respectively. Compared with other sensors, the key component of the proposed sensor is only 1 cm in length, which makes it compact and easy to manufacture. The geometric parameters, such as the position and radius of the pores, are less likely to deviate from the ideal values, which helps to reduce the impact of manufacturing tolerances on the sensing performance.
Comprehensive Computational Model for Coupled Fluid Flow, Mass Transfer, and Light Supply in Tubular Photobioreactors Equipped with Glass Sponges
Authors: Mink Albert , Schediwy Kira , Posten Clemens , Nirschl Hermann , Simonis Stephan , Krause Mathias J.
Published: October 2022

The design and optimization of photobioreactor(s) (PBR) benefit from the development of robust and quantitatively accurate computational fluid dynamics (CFD) models, which incorporate the complex interplay of fundamental phenomena. In the present work, we propose a comprehensive computational model for tubular photobioreactors equipped with glass sponges. The simulation model requires a minimum of at least three submodels for hydrodynamics, light supply, and biomass kinetics, respectively. First, by modeling the hydrodynamics, the light–dark cycles can be detected and the mixing characteristics of the flow (besides the mass transport) can be analyzed. Second, the radiative transport model is deployed to predict the local light intensities according to the wavelength of the light and scattering characteristics of the culture. The third submodel implements the biomass growth kinetic by coupling the local light intensities to hydrodynamic information of the CO2 concentration, which allows to predict the algal growth. In combination, the novel mesoscopic simulation model is applied to a tubular PBR with transparent walls and an internal sponge structure. We showcase the coupled simulation results and validate specific submodel outcomes by comparing the experiments. The overall flow velocity, light distribution, and light intensities for individual algae trajectories are extracted and discussed. Conclusively, such insights into complex hydrodynamics and homogeneous illumination are very promising for CFD-based optimization of PBR.
Legal Regulations of Restrictions of Air Pollution Made by Mobile Positive Pressure Fans—The Case Study for Europe: A Review
Authors: Warguła Łukasz , Kaczmarzyk Piotr
Published: October 2022

This paper presents a review of mobile positive pressure ventilation fans for use in rescue operations available on the European market in correlation with the approval regulations of the drive units. The authors determined the approval limits for harmful compound emissions by their power units, as applicable within the European Union. The purpose of this paper is to estimate the emissions of harmful compounds from the exhausts of rescue fan power units. It was demonstrated that electric fans are not in direct competition with internal combustion fans because they are provided in different power ranges, and 74% of the electric fan market falls between 1.1 kW and 2.2 kW, whereas fans powered by combustion engines are offered in a much higher power range from 0.7 kW to 92 kW, and the most popular power range offered by manufacturers is from 3.4 kW to 6.3 kW (57% of the market). On the basis of the limits derived from approval tests it can be demonstrated that 90% of engines on the European market which are used in fans (spark ignition (SI) engine up to 19 kW) are allowed carbon monoxide (CO) emissions of 610 g/kWh and hydrocarbon and nitrogen oxide emissions (HC + NOx) of 8 g/kWh.
The Influence of Fracturing Fluid Volume on the Productivity of Coalbed Methane Wells in the Southern Qinshui Basin
Authors: Chen Wenwen , Wang Xiaoming , Tu Mingkai , Qu Fengjiao , Chao Weiwei , Chen Wei , Hou Shihui
Published: October 2022

Hydraulic fracturing is the main technical means for the reservoir stimulation of coalbed methane (CBM) vertical wells. The design of fracturing fluid volume (FFV) is mainly through numerical simulation, and the numerical simulation method does not fully consider the water block damage caused by the leakage of fracturing fluid into the reservoir. In this work, the variance analysis method was used to analyze the production data of 1238 CBM vertical wells in the Fanzhuang block and Zhengzhuang block of the Qinshui Basin, to clarify the relationship between the FFV and the peak gas production (PGP) under the different ratios of critical desorption pressure to reservoir pressure (Rc/r), and to reveal the controlling mechanism of fracturing fluid on CBM migration. The results show that both the FFV and Rc/r have a significant impact on gas production. When Rc/r < 0.5, the PGP decreases with the increase of the FFV, and the FFV that is beneficial to gas production is 200–500 m3. When Rc/r > 0.5, the PGP increases first and then decreases with the increase of FFV. Specifically, the FFV that is favorable for gas production is 500–700 m3. Excessive FFV does not significantly increase the length of fractures due to leaks in the coal reservoir. Instead, it is more likely to invade and stay in smaller pores, causing water block damage and reducing gas production. Reservoirs with high Rc/r have larger displacement pressure, which can effectively overcome the resistance of liquid migration in pores, thereby reducing the damage of the water block. Therefore, different reservoir conditions need to match the appropriate fracturing scale. This study can provide guidance for the optimal design of hydraulic fracturing parameters for CBM wells.
Analysis and Synthesis of Coordinated Control Systems for Automated Road Vehicles
Authors: Németh Balázs
Published: October 2022

Through the automation of road vehicles, several smart actuators have been developed, with which various automated and autonomous functionalities can be performed [...]
Optimization Process Applied in the Thermal and Luminous Design of High Power LED Luminaires
Authors: Barbosa Jose Luiz F. , Coimbra Antonio P. , Simon Dan , Calixto Wesley P.
Published: October 2022

This work proposes the design of an optimization method for high-power LED luminaires with the introduction of new evaluation metrics. A luminaire geometry computational method is deployed to conduct thermal and optical analysis. This current effort novels by designing a tool that enables the analysis of uniformity for individual luminaire over the target plane in accordance with international regulatory standards. Additionally, adequate thermal management is conducted to guarantee nominal operation standard values determined by LED vendors. The results of this optimization method present luminaire models with different geometries that allow the stabilization of the temperature within the safety and uniform illuminance distribution thresholds. The resulting solution proposes the design of a 2×2 HP-LED rectangular luminaire. During simulations, the temperature of the LED reaches a maximum value of 73.9∘ C in a steady state with a uniform index of 0.228 for its individual luminaire. The overall uniform index identified for two separate and adjacent luminaire points in a pedestrian walk is 0.5413 with a minimal illuminance of 36.95 lx, maximum illuminance of 93.65 lx and average illuminance of 68.27 lx. Overall, we conclude that the currently adopted metric, which takes into consideration only the ratio between the minimum and the average illuminance, is not efficient and it cannot distinguish different luminaire geometry standards according to their uniform illuminance distribution. The metric proposed and designed in this work is capable of evaluating illuminance and thermal threshold criteria, as well as classifying different sorts of luminaries.
Real-Time Measurements of Formaldehyde Emissions from Modern Vehicles
Authors: Suarez-Bertoa Ricardo , Selleri Tommaso , Gioria Roberto , Melas Anastasios D. , Ferrarese Christian , Franzetti Jacopo , Arlitt Bertold , Nagura Naoki , Hanada Takaaki , Giechaskiel Barouch
Published: October 2022

Formaldehyde (HCHO), a carcinogenic carbonyl compound and precursor of tropospheric ozone, can be found in vehicle exhaust. Even though the continuous monitoring of HCHO has been recommended, the real-world emissions from the road transport sector are not commonly available. The main reason for this knowledge gap has been the difficulty to measure HCHO in real-time and during real-world testing. This, for instance, increases the uncertainty of the O3 simulated by air quality models. The present study investigates real-time HCHO measurements comparing three Fourier Transform InfraRed spectrometers (FTIRs) and one Quantum Cascade Laser InfraRed spectrometer (QCL-IR) directly sampling from the exhaust of one gasoline passenger car, one Diesel commercial vehicle and one Diesel heavy-duty vehicle, all meeting recent European emission standards (Euro 6/VI). Non-negligible emissions of HCHO were measured from the Diesel light-duty vehicle, with emissions increasing as temperature decreased. Relatively low emissions were measured for the gasoline car and the Diesel heavy-duty vehicle. The results showed a good correlation between the different instruments under all the conditions tested (in most cases R2 > 0.9). Moreover, it was shown that HCHO can be accurately measured during on-road and real-world-like tests using instruments based on FTIR and QCL-IR technologies.
Law and Mechanism Study on Salt Resistance of Nonionic Surfactant (Alkyl Glycoside) Foam
Authors: Xiao Bao , Ye Zhongbin , Wang Junqi , Tang Lei , Lai Nanjun
Published: October 2022

In this paper, the effects of three cations, Ca2+, Mg2+, and Na+, on the stability of APG foams were investigated experimentally. The results show that cations can slow down the process of liquid drainage and coarsening of APG foam, which is beneficial to the stability of the foam. The salt resistance mechanism of nonionic surfactant (APG) was investigated by molecular dynamics simulation and compared with that of anionic surfactant (SDS) foam. Firstly, the distribution characteristics of cations in APG foam and SDS foam were explored. It was found that the cations in the APG foam were mainly distributed in the water layer away from the head groups, and the cations in the SDS foam were more likely to appear near the head groups. Then, the hydration of the head groups and the cation was investigated. The results show that cations have little effect on the number of water molecules in the hydration layer of APG head groups but will reduce the diffusion capacity of water molecules and increase the water retention capacity of the foam film, thereby enhancing the foam stability. The addition of cations will reduce the water retention capacity of the SDS foam film. In addition, the behavior of surfactant head and tail groups was also analyzed. It was found that the cations made the head groups of APG more inclined to be aligned perpendicular to the liquid interface, and the tail groups were more inclined to realize a cross-arrangement and cover the gas–liquid interface. This can not only slow down the gas phase mass transfer process of the adjacent foam and slow down the coarsening process of the foam but also increase the viscoelasticity and anti-disturbance ability of the foam film. The cations will weaken the staggered arrangement of the SDS molecular tail groups, and at the same time, will cause the SDS molecules to aggregate, which greatly reduces the stability of the foam.
Germination Energy, Germination Capacity and Microflora of Allium cepa L. Seeds after RF Plasma Conditioning
Authors: Pawłat Joanna , Starek-Wójcicka Agnieszka , Kopacki Marek , Terebun Piotr , Kwiatkowski Michał , Sujak Agnieszka , Pascuzzi Simone , Santoro Francesco , Andrejko Dariusz
Published: October 2022

This paper presents the results of an experiment on the effect of the cold plasma (He+O2 or He+Air) pre-sowing stimulation of seeds of the Wolska cultivar of onion on the process of their germination. Four groups of seeds characterized by different exposure times (60, 120, 240 and 480 s) were used. Untreated seeds were used as a control. The distance between the electrode and the tested material was 50 mm. Pre-sowing plasma stimulation improved germination parameters such as germination capacity and germination energy for all the tested groups relative to the control. The highest fractions of germinated seeds were observed for an exposure time of 120 s. Analysis of the data showed a statistically significant impact of RF plasma on the seed germination parameters of the onion. SEM analysis showed that the interaction with plasma produced tension in the cells, leading to a change in their shape. No visible damage to the onion seed cells was observed, apart from the effect of depletion of the upper wax layer. The best influence on pathogenic fungi was when the group of seeds underwent 240 and 480 s of exposure to plasma fumigation, especially using the He+Air RF plasma jet.
Modeling of Thermal-Lag Engine with Validation by Experimental Data
Authors: Cheng Chin-Hsiang , Phung Duc-Thuan
Published: October 2022

Thermal-lag engines are external combustion engines with a single moving piston. This feature leads to lower manufacturing and maintenance costs than traditional Stirling engines. Although the original concept of thermal-lag engines was invented roughly 35 years ago, the information on thermal-lag engines is still limited. Therefore, this study focuses on thermal-lag engine performance by developing a three-dimensional computational fluid dynamics (CFD) model. The grid independence check and the time step independence check are firstly performed to select the number of elements and size of the time step for simulation. The CFD model is then validated by the experimental data, which were collected by measuring an existing prototype engine. It has been found that the CFD predictions are well fitted to the experimental data over the range of engine speed from 200 to 1600 rpm at temperatures of 1173 or 1273 K. Furthermore, the CFD model predicts that the maximum engine power is 21.1 W while the prototype engine practically generates the highest power of 22.35 W at 1000 rpm and 1273 K. Finally, a further parametric study shows that crank radius, piston diameter, working gas mass, working gas species, and heating temperature significantly affect engine power.
Energy Management System for Grid-Connected Nanogrid during COVID-19
Authors: Jamal Saif , Pasupuleti Jagadeesh , Rahmat Nur Azzammudin , Tan Nadia M. L.
Published: October 2022

An effective energy management system (EMS) was designed based on the Stateflow (SF) approach for a grid-connected nanogrid (NG) composed of a photovoltaic (PV) array with a battery bank and supercapacitor (SC) energy storage system (ESS). The PV energy system, battery bank and SC (ESS), dual active bridge DC/DC converters, DC/AC inverters, control algorithms, and controllers were developed to test the operation of the NG. The average and high-frequency power components are separated using frequency division of the ESS power utilizing a low-pass filter; the average power is absorbed by the battery bank, while the high-frequency power is absorbed by the SC. The aim of this paper is to design an EMS to manage the energy of a grid-connected NG system considering the availability of the PV array, ESS, and demand requirements. Different scenarios of operation were tested to check the EMS behaviour during the day with a random demand profile, including: (1) a PV array with the grid supplying the load without an EMS; (2) a PV array, batteries, and the grid supplying the load with an EMS; (3) a PV array, batteries, an SC, and the grid supplying the load with an EMS; (4) a PV array, batteries, an SC, and the grid supplying the load with an EMS, with load profile reduction by 20% due to COVID-19. As per the simulation results, the proposed EMS enables the flow of power in the NG system and demonstrates the impact on the ESS by minimising carbon emissions via a reduction in grid consumption. Furthermore, the SF method is regarded as a helpful alternative to popular design approaches employing conventional software tools.
Development of a Simple Methodology Using Meteorological Data to Evaluate Concentrating Solar Power Production Capacity
Authors: Tavares Ailton M. , Conceição Ricardo , Lopes Francisco M. , Silva Hugo G.
Published: October 2022

Evaluation of the Concentrating Solar Power capacity factor is critical to support decision making on possible regional energy investments. For such evaluations, the System Advisor Model is used to perform capacity factor assessments. Among the required data, information concerning direct normal irradiance is fundamental. In this context, the Engerer model is used to estimate direct normal irradiance hourly values out of global horizontal irradiance ground measurements and other observed meteorological variables. Model parameters were calibrated for direct normal irradiance measurements in Évora (Southern Portugal), being then applied to a network of 90 stations, part of the Portuguese Meteorological Service. From the modelled direct normal irradiance, and for stations that comprise 20 years of data, typical meteorological years were determined. Finally, to identify locations of interest for possible installations of Concentrating Solar Power systems, annual direct normal irradiance availabilities and the respective capacity factor, for a predefined power plant using the System Advisor Model, were produced. Results show annual direct normal irradiance availabilities and capacity factors of up to ~2310 kWh/m2 and ~36.2% in Castro Marim and in Faro, respectively. Moreover, this study supports energy policies that would promote Concentrating Solar Power investments in Southern Portugal (Alentejo and Algarve regions) and eastern centre Portugal (Beira Interior region), which have capacity factors above 30%.
Assessment of the Impact of Flow Changes and Water Management Rules in the Dam Reservoir on Energy Generation at the Jeziorsko Hydropower Plant
Authors: Nowak Bogumił , Andrzejak Anna , Filipiak Grzegorz , Ptak Mariusz , Sojka Mariusz
Published: October 2022

This paper presents the impact of flow changes in the Warta River and water management rules regarding the Jeziorsko dam reservoir on the energy production by the hydropower plant in the period 1995–2021. The Jeziorsko dam reservoir was built in 1986. It is the second largest dam reservoir in Poland in terms of surface area. In 1994, a hydropower plant with an installed capacity of 4.89 MW started operation. The study results show the average annual energy production from 1995 to 2021 at a level of 18,718 MWh. On the other hand, energy production largely changed from year to year, from 12,432 MWh (in 2019) to 26,916 MWh (in 2001). The droughts that have occurred in the Warta River basin over the past two decades have had a major impact on energy production. As a consequence of the drought, it was not possible to maintain the required water level in the reservoir. Moreover, a change in the rules for the reservoir’s management that led to lower water levels in the reservoir by 1.5 m between April and June was important from the point of view of energy production. Improving the efficiency of energy production requires changing the rules of water management in the reservoir. More flexible reservoir operation schemes should be considered, including operational management based on meteorological and hydrological forecasts. Moreover, other criteria should also be considered, such as maintaining environmental flows, ensuring protection from flooding, and operating a nature reserve around the reservoir.
Analysis of Particle Emissions from a Jet Engine Including Conditions of Afterburner Use
Authors: Jasiński Remigiusz
Published: October 2022

Particle emissions from aircraft engines are mainly related to the emission of particles with very small diameters. The phenomena of the formation of particles in various operating conditions of turbine engines are known. However, it is difficult to find the results of research on the use of the afterburner in the literature. Increased aviation activity within military airports and situations such as air shows are associated with a very intense emission of particles, and pose a direct threat to human health. This article presents an analysis of particulate matter emissions from a military aircraft engine, with particular emphasis on operation with an afterburner. The parameters of the emission of particles determined were: PM Number Emissions Index (EIN), Particle Number Emissions Intensity (EN), PM Mass Emission Index (EIM), PM Mass Emission Intensity (EM), Differential Particle Number Emission Index, Differential Particle Volume Emission Index, and Differential Particle Mass Emission Index. The value of EIN for the afterburner use was the lowest among the whole operation range of the engine and was equal to 1.3 × 1015 particles per kilogram. The use of an afterburner resulted in a sharp increase in the EIM coefficient, which reached 670 mg/kg. Despite a very large increase in fuel consumption, the EIM coefficient turned out to be over 60 times greater than in the case of 100% engine thrust.