bluuebunny/crossref_metadata_2025 huggingface dataset:
Microfluidic-Assisted Preparation of Targeted pH-Responsive Polymeric Micelles Improves Gemcitabine Effectiveness in PDAC: In Vitro Insights
Authors: Iacobazzi Rosa Maria , Arduino Ilaria , Di Fonte Roberta , Lopedota Angela Assunta , Serratì Simona , Racaniello Giuseppe , Bruno Viviana , Laquintana Valentino , Lee Byung-Chul , Silvestris Nicola , Leonetti Francesco , Denora Nunzio , Porcelli Letizia , Azzariti Amalia
Published: December 2021

Pancreatic ductal adenocarcinoma (PDAC) represents a great challenge to the successful delivery of the anticancer drugs. The intrinsic characteristics of the PDAC microenvironment and drugs resistance make it suitable for therapeutic approaches with stimulus-responsive drug delivery systems (DDSs), such as pH, within the tumor microenvironment (TME). Moreover, the high expression of uPAR in PDAC can be exploited for a drug receptor-mediated active targeting strategy. Here, a pH-responsive and uPAR-targeted Gemcitabine (Gem) DDS, consisting of polymeric micelles (Gem@TpHResMic), was formulated by microfluidic technique to obtain a preparation characterized by a narrow size distribution, good colloidal stability, and high drug-encapsulation efficiency (EE%). The Gem@TpHResMic was able to perform a controlled Gem release in an acidic environment and to selectively target uPAR-expressing tumor cells. The Gem@TpHResMic displayed relevant cellular internalization and greater antitumor properties than free Gem in 2D and 3D models of pancreatic cancer, by generating massive damage to DNA, in terms of H2AX phosphorylation and apoptosis induction. Further investigation into the physiological model of PDAC, obtained by a co-culture of tumor spheroids and cancer-associated fibroblast (CAF), highlighted that the micellar system enhanced the antitumor potential of Gem, and was demonstrated to overcome the TME-dependent drug resistance. In vivo investigation is warranted to consider this new DDS as a new approach to overcome drug resistance in PDAC.
A Comparative Study of Serum Angiogenic Biomarkers in Cirrhosis and Hepatocellular Carcinoma
Authors: Pocino Krizia , Napodano Cecilia , Marino Mariapaola , Di Santo Riccardo , Miele Luca , De Matthaeis Nicoletta , Gulli Francesca , Saporito Raffaele , Rapaccini Gian Ludovico , Ciasca Gabriele , Basile Umberto
Published: December 2021

Background: Hepatocellular carcinoma (HCC) is a global health problem associated with chronic liver disease. Its pathogenesis varies according to the underlying etiological factors, although in most cases it develops from liver cirrhosis. The disease progression is accompanied by pathological angiogenesis, which is a prerequisite that favors the development of HCC. Aims: This study aims at contributing to our understanding of the role of angiogenic factors in the progression of liver disease. For this purpose, we evaluate the clinical significance of serum angiogenic markers (VEGF, Ang-1, Ang-2, the angiopoietin receptor Tie1/2, HGF, and PECAM-1) first in cirrhotic and HCC patients separately, and then comparing cirrhotic patients with and without HCC. Materials and Methods: We enrolled 62 patients, out of whom 33 were diagnosed with HCC and 29 with liver cirrhosis without signs of neoplasia. Patients underwent venous blood sampling before and after receiving treatments for the diagnosed disease. Serum markers were evaluated using ELISA assays for Tie1 and the Bio-Plex Multiplex system for the remaining ones. Biomarker levels were investigated as a function of clinical scores for disease staging (MELD and Fibrosis Index, FI). Results: In cirrhotic patients, Ang-1 and Ang-2 correlate with MELD (ρAng-1 = −0.73, p = 2E−5) and FI (ρAng-1 = −0.52, p = 7E−3, ρAng-2 = 0.53, p = 3E−3). A reduction of Ang-2 levels (p = 0.047) and of the Ang-2/Ang-1 ratio (p = 0.031) is observed in cirrhotic patients diagnosed with viral hepatitis after antiviral treatments. In HCC patients, Ang-1 negatively correlates with FI (ρ = −0.63, p = 1E−4), and PECAM-1 positively correlates with MELD (ρ = 0.44, p = 0.01). A significant Ang-1 reduction was observed in deceased patients during the study compared to ones who survived (p = 0.01). In HCC patients, VEGF levels were increased after tumor treatment (p = 0.037). Notably, HGF levels in cirrhotic patients with HCC are significantly raised (p = 0.017) compared to that in those without HCC. Conclusions: Our results suggest that serum angiogenic markers, with emphasis on Ang-1/2, can contribute to the development of quantitative tools for liver disease staging and therapy monitoring. The comparison between cirrhotic patients with and without HCC suggests that HGF levels are potentially useful for monitoring the insurgence of HCC after a cirrhosis diagnosis. High Ang-1 levels in HCC patients appear to have a protective role as well as prognostic significance.
Classification of Clinically Significant Prostate Cancer on Multi-Parametric MRI: A Validation Study Comparing Deep Learning and Radiomics
Authors: Castillo T. Jose M. , Arif Muhammad , Starmans Martijn P. A. , Niessen Wiro J. , Bangma Chris H. , Schoots Ivo G. , Veenland Jifke F.
Published: December 2021

The computer-aided analysis of prostate multiparametric MRI (mpMRI) could improve significant-prostate-cancer (PCa) detection. Various deep-learning- and radiomics-based methods for significant-PCa segmentation or classification have been reported in the literature. To be able to assess the generalizability of the performance of these methods, using various external data sets is crucial. While both deep-learning and radiomics approaches have been compared based on the same data set of one center, the comparison of the performances of both approaches on various data sets from different centers and different scanners is lacking. The goal of this study was to compare the performance of a deep-learning model with the performance of a radiomics model for the significant-PCa diagnosis of the cohorts of various patients. We included the data from two consecutive patient cohorts from our own center (n = 371 patients), and two external sets of which one was a publicly available patient cohort (n = 195 patients) and the other contained data from patients from two hospitals (n = 79 patients). Using multiparametric MRI (mpMRI), the radiologist tumor delineations and pathology reports were collected for all patients. During training, one of our patient cohorts (n = 271 patients) was used for both the deep-learning- and radiomics-model development, and the three remaining cohorts (n = 374 patients) were kept as unseen test sets. The performances of the models were assessed in terms of their area under the receiver-operating-characteristic curve (AUC). Whereas the internal cross-validation showed a higher AUC for the deep-learning approach, the radiomics model obtained AUCs of 0.88, 0.91 and 0.65 on the independent test sets compared to AUCs of 0.70, 0.73 and 0.44 for the deep-learning model. Our radiomics model that was based on delineated regions resulted in a more accurate tool for significant-PCa classification in the three unseen test sets when compared to a fully automated deep-learning model.
Radical or Not-So-Radical Prostatectomy: Do Surgical Margins Matter?
Authors: Grypari Ioanna Maria , Zolota Vasiliki , Tzelepi Vasiliki
Published: December 2021

Prostate cancer is the second most common malignancy in men, and prostatectomy is the treatment of choice for most patients with at least low risk of progression. The presence of positive margins in the radical prostatectomy specimen is considered an adverse pathologic feature, and may prompt additional therapeutic intervention in the patients. The absence of a distinct capsule around the prostate and intraoperative manipulations that aim to minimize postoperative adverse effects, complicate its wide removal. Proper handling of the specimen during the gross processing is essential for accurate determination of the status of margins or resection. Positive margins, defined as the presence of neoplastic glands in the highlighted-with-ink margin of resection, range from 6–38%. The surgical technique, surgeon’s expertise and tumor (i.e., grade and stage) and patients’ (i.e., BMI) characteristics affect the rate of margin positivity. Extensive or multifocal and nonanterior/nonapical positive margins are linked with higher recurrence rates, especially in organ-confined disease, underscoring the need for treating these patients more aggressively. In summary, detailed description of the status of the margins should be performed in every pathology report to determine patients’ prognosis and the most appropriate therapeutic plan.
Impact of Alternative Splicing Variants on Liver Cancer Biology
Authors: Marin Jose J. G. , Reviejo Maria , Soto Meraris , Lozano Elisa , Asensio Maitane , Ortiz-Rivero Sara , Berasain Carmen , Avila Matias A. , Herraez Elisa
Published: December 2021

The two most frequent primary cancers affecting the liver, whose incidence is growing worldwide, are hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), which are among the five most lethal solid tumors with meager 5-year survival rates. The common difficulty in most cases to reach an early diagnosis, the aggressive invasiveness of both tumors, and the lack of favorable response to pharmacotherapy, either classical chemotherapy or modern targeted therapy, account for the poor outcome of these patients. Alternative splicing (AS) during pre-mRNA maturation results in changes that might affect proteins involved in different aspects of cancer biology, such as cell cycle dysregulation, cytoskeleton disorganization, migration, and adhesion, which favors carcinogenesis, tumor promotion, and progression, allowing cancer cells to escape from pharmacological treatments. Reasons accounting for cancer-associated aberrant splicing include mutations that create or disrupt splicing sites or splicing enhancers or silencers, abnormal expression of splicing factors, and impaired signaling pathways affecting the activity of the splicing machinery. Here we have reviewed the available information regarding the impact of AS on liver carcinogenesis and the development of malignant characteristics of HCC and iCCA, whose understanding is required to develop novel therapeutical approaches aimed at manipulating the phenotype of cancer cells.
Smart Designs of Mo Based Electrocatalysts for Hydrogen Evolution Reaction
Authors: Gao Xingyuan , Deng Huilin , Dai Qiuping , Zeng Quanlong , Qiu Shuxian , Lu Xihong
Published: December 2021

As a sustainable and clean energy source, hydrogen can be generated by electrolytic water splitting (i.e., a hydrogen evolution reaction, HER). Compared with conventional noble metal catalysts (e.g., Pt), Mo based materials have been deemed as a promising alternative, with a relatively low cost and comparable catalytic performances. In this review, we demonstrate a comprehensive summary of various Mo based materials, such as MoO2, MoS2 and Mo2C. Moreover, state of the art designs of the catalyst structures are presented, to improve the activity and stability for hydrogen evolution, including Mo based carbon composites, heteroatom doping and heterostructure construction. The structure–performance relationships relating to the number of active sites, electron/ion conductivity, H/H2O binding and activation energy, as well as hydrophilicity, are discussed in depth. Finally, conclusive remarks and future works are proposed.
Dunking into the Lipid Bilayer: How Direct Membrane Binding of Nucleoporins Can Contribute to Nuclear Pore Complex Structure and Assembly
Authors: Hamed Mohamed , Antonin Wolfram
Published: December 2021

Nuclear pore complexes (NPCs) mediate the selective and highly efficient transport between the cytoplasm and the nucleus. They are embedded in the two membrane structure of the nuclear envelope at sites where these two membranes are fused to pores. A few transmembrane proteins are an integral part of NPCs and thought to anchor these complexes in the nuclear envelope. In addition, a number of nucleoporins without membrane spanning domains interact with the pore membrane. Here we review our current knowledge of how these proteins interact with the membrane and how this interaction can contribute to NPC assembly, stability and function as well as shaping of the pore membrane.
Elastic Laminar Reorganization Occurs with Outward Diameter Expansion during Collateral Artery Growth and Requires Lysyl Oxidase for Stabilization
Authors: McEnaney Ryan M. , McCreary Dylan D. , Skirtich Nolan O. , Andraska Elizabeth A. , Sachdev Ulka , Tzeng Edith
Published: December 2021

When a large artery becomes occluded, hemodynamic changes stimulate remodeling of arterial networks to form collateral arteries in a process termed arteriogenesis. However, the structural changes necessary for collateral remodeling have not been defined. We hypothesize that deconstruction of the extracellular matrix is essential to remodel smaller arteries into effective collaterals. Using multiphoton microscopy, we analyzed collagen and elastin structure in maturing collateral arteries isolated from ischemic rat hindlimbs. Collateral arteries harvested at different timepoints showed progressive diameter expansion associated with striking rearrangement of internal elastic lamina (IEL) into a loose fibrous mesh, a pattern persisting at 8 weeks. Despite a 2.5-fold increase in luminal diameter, total elastin content remained unchanged in collaterals compared with control arteries. Among the collateral midzones, baseline elastic fiber content was low. Outward remodeling of these vessels with a 10–20 fold diameter increase was associated with fractures of the elastic fibers and evidence of increased wall tension, as demonstrated by the straightening of the adventitial collagen. Inhibition of lysyl oxidase (LOX) function with β-aminopropionitrile resulted in severe fragmentation or complete loss of continuity of the IEL in developing collaterals. Collateral artery development is associated with permanent redistribution of existing elastic fibers to accommodate diameter growth. We found no evidence of new elastic fiber formation. Stabilization of the arterial wall during outward remodeling is necessary and dependent on LOX activity.
Effect of Conventional and Electronic Cigarettes Smoking on the Color Stability and Translucency of Tooth Colored Restorative Materials: An In Vitro Analysis
Authors: Alnasser Hamad A. , Elhejazi Ahmed A. , Al-Abdulaziz Abdalrahman A. , Alajlan Saad S. , Habib Syed Rashid
Published: December 2021

This in vitro study compared the effects of conventional and electronic cigarettes on the aesthetics (color stability and translucency) of two types of composite resins: micro and nano-hybrid. Methods: A total of 120 specimens from two different composite materials Filtek Z250 XT (Nano-hybrid, 3M) and Filtek Z250 (Micro-hybrid, 3M) were divided into four groups (n = 30); shade A2 was used. The samples were exposed to conventional and electronic cigarette smoke via a custom made chamber device. The color values and measurements were recorded using a spectrophotometer before and after the exposure. The color and translucency were evaluated using the three-dimensional CIE Lab. Results: There was a significant change in the color (ΔE) and the translucency parameter (TP) in all of the specimens exposed to electronic cigarettes and conventional cigarettes. The results showed that the highest ΔE mean is for the nano-hybrid composite exposed to conventional cigarettes with 1.74 ΔE while the same material is 0.64 under the electronic cigarettes and the difference is significant with (p < 0.05). The micro-hybrid composite data showed less changes in color under both exposures with 0.85 ΔE mean under the conventional cigarette smoke and 0.48 under the electronic cigarette smoke with (p < 0.004). Conclusions: The conventional cigarette smoke has more effect on the color stability of the composite resins than electronic cigarettes. From a clinical point of view, the effect of smoke exposure on the tested specimens’ color, for the time duration to which the specimens were exposed, were moderate (ΔE < 2). The micro-hybrid composites showed better color stability as compared to the nano-hybrid composites.
Natural History Observations on a Population of Vesperus luridus (Coleoptera: Cerambycidae) in Central Italy
Authors: Luiselli Luca , Luiselli Raffaele , Giustini Marina , Rugiero Lorenzo , Dendi Daniele
Published: December 2021

Natural history observations were made, during August–September 2021, on a population of the ecologically poorly known Vesperus luridus (Cerambycidae) at a hilly locality of Latium, Central Italy. These beetles were searched for by night along a 170 m long transect, with the help of hand torches. During the field surveys, we recorded a total of 130 individuals, of which 128 were males and 2 females. All individuals were observed between 21 h 45 and 01 h 15, with above-ground activity peaking from 22 h 45 to 23 h 45. The minimum observed density per day showed a rapid increase to a peak at the end of August, followed by a slower decrease in the following two weeks. Mean male density was 0.32 individuals per transect m2, whereas only two females were observed (mean density = 0.006 individuals per transect m2). Most individuals were found on trees, and they appeared to be highly attracted to artificial lights. One female, situated on a tree at a height of 170 cm, was surrounded by five courting males.
One for Sorrow
Authors: Griffin Darren K.
Published: December 2021

“Did it work [...]
Exact Learning Augmented Naive Bayes Classifier
Authors: Sugahara Shouta , Ueno Maomi
Published: December 2021

Earlier studies have shown that classification accuracies of Bayesian networks (BNs) obtained by maximizing the conditional log likelihood (CLL) of a class variable, given the feature variables, were higher than those obtained by maximizing the marginal likelihood (ML). However, differences between the performances of the two scores in the earlier studies may be attributed to the fact that they used approximate learning algorithms, not exact ones. This paper compares the classification accuracies of BNs with approximate learning using CLL to those with exact learning using ML. The results demonstrate that the classification accuracies of BNs obtained by maximizing the ML are higher than those obtained by maximizing the CLL for large data. However, the results also demonstrate that the classification accuracies of exact learning BNs using the ML are much worse than those of other methods when the sample size is small and the class variable has numerous parents. To resolve the problem, we propose an exact learning augmented naive Bayes classifier (ANB), which ensures a class variable with no parents. The proposed method is guaranteed to asymptotically estimate the identical class posterior to that of the exactly learned BN. Comparison experiments demonstrated the superior performance of the proposed method.
A Probabilistic Re-Intepretation of Confidence Scores in Multi-Exit Models
Authors: Pomponi Jary , Scardapane Simone , Uncini Aurelio
Published: December 2021

In this paper, we propose a new approach to train a deep neural network with multiple intermediate auxiliary classifiers, branching from it. These ‘multi-exits’ models can be used to reduce the inference time by performing early exit on the intermediate branches, if the confidence of the prediction is higher than a threshold. They rely on the assumption that not all the samples require the same amount of processing to yield a good prediction. In this paper, we propose a way to train jointly all the branches of a multi-exit model without hyper-parameters, by weighting the predictions from each branch with a trained confidence score. Each confidence score is an approximation of the real one produced by the branch, and it is calculated and regularized while training the rest of the model. We evaluate our proposal on a set of image classification benchmarks, using different neural models and early-exit stopping criteria.
Error Probability Mitigation in Quantum Reading Using Classical Codes
Authors: Fernandes Pereira Francisco Revson , Mancini Stefano
Published: December 2021

A general framework describing the statistical discrimination of an ensemble of quantum channels is given by the name quantum reading. Several tools can be applied in quantum reading to reduce the error probability in distinguishing the ensemble of channels. Classical and quantum codes can be envisioned for this goal. The aim of this paper is to present a simple but fruitful protocol for this task using classical error-correcting codes. Three families of codes are considered: Reed–Solomon codes, BCH codes, and Reed–Muller codes. In conjunction with the use of codes, we also analyze the role of the receiver. In particular, heterodyne and Dolinar receivers are taken into consideration. The encoding and measurement schemes are connected by the probing step. As probes, we consider coherent states. In such a simple manner, interesting results are obtained. As we show, there is a threshold below which using codes surpass optimal and sophisticated schemes for any fixed rate and code. BCH codes in conjunction with Dolinar receiver turn out to be the optimal strategy for error mitigation in quantum reading.
Optimization of the Spectrum Splitting and Auction for 5th Generation Mobile Networks to Enhance Quality of Services for IoT from the Perspective of Inclusive Sharing Economy
Authors: Chiang Johannes K. , Lin Chien-Liang , Chiang Yi-Fang , Su Yushun
Published: December 2021

Fifth generation (5G) mobile networks can accomplish enhanced communication capabilities and desired to connect things in addition to people. By means of optimally splitting the spectrum to integrate more efficient segments, mobile operators can deliver better Quality of Services (QoS) for Internet of Things (IoT), even the nowadays so-called metaverse need broadband mobile communication. Drawing on the Theory of Quality Value Transformation, we developed a 5G ecosystem as a sustainable organic coalition constituted of planners, providers, and users. Most importantly, we put forward the altruism as the ethics drive for the organic cooperative evolution to sustain the inclusive sharing economy to solve the problem of the Theory of Games and Economic Behavior. On the top of the collaboration framework for the coalition game for 5G, we adopted Pareto Optimality as the target situation for the optimization via cooperative evolution and further apply ISO 25000 to define the metrics for the value of 5G corresponding to Pareto Frontier. Based on the collaboration framework as above, we conducted a survey to gather the features and costs for the 5G spectrum in relation to IoT and the financial status of the mobile operators as the constraint for the optimization. Taking Simultaneous Multi-Round Auction (SMRA) as the standard rule for spectrum auction, we developed a novel optimization program of two hybrid metaheuristics with the combination of Simulated Annealing (SA), Genetic Algorithm (GA), and Random Optimization (RO) for the multiple objectives of quality, usability, and costs. The results of the simulation show that the coalition game for 5G spectrum auction is a dynamic group decision in which the government authority and mobile operators can achieve a synergy to maximize the profits, quality score, and usability, and minimize the costs. Last but not least, the hybrid metaheuristic with SA and RO is more efficient and effective than that with GA and BO, from the perspective of inclusive sharing economy. It is the first study of its kind as we know.
Augmentation of Heat Transfer in a Circular Channel with Inline and Staggered Baffles
Authors: Al Nuwairan Muneerah , Souayeh Basma
Published: December 2021

This numerical investigation presents the effects of the position of baffles in the shape of a circle’s segment placed inside a circular channel to improve the thermal and flow performance of a solar air heater. Three different baffles’ positions with Reynolds number varying between 10,000 to 50,000 were investigated computationally. The k-omega SST model was used for solving the governing equations. Air was taken as the working fluid. Three pitch ratios (Y = 3, 4, and 5) were considered, while the height of the baffles remained fixed. The result showed an enhancement in Nusselt number, friction factor, j-factor, and thermal performance factor. Staggered exit-length baffles showed maximum enhancement in heat transfer and pressure drop, while inline inlet-length baffles showed the least enhancement. For a pitch ratio of Y = 3.0, the enhancement in all parameters was the highest, while for Y = 5.0, the enhancement in all parameters was the least. The highest thermal performance factor of 1.6 was found for SEL at Y = 3.0.
Robust Enough? Exploring Temperature-Constrained Energy Transition Pathways under Climate Uncertainty
Authors: Nicolas Claire , Tchung-Ming Stéphane , Bahn Olivier , Delage Erick
Published: December 2021

In this paper, we study how uncertainties weighing on the climate system impact the optimal technological pathways the world energy system should take to comply with stringent mitigation objectives. We use the TIAM-World model that relies on the TIMES modelling approach. Its climate module is inspired by the DICE model. Using robust optimization techniques, we assess the impact of the climate system parameter uncertainty on energy transition pathways under various climate constraints. Unlike other studies we consider all the climate system parameters which is of primary importance since: (i) parameters and outcomes of climate models are all inherently uncertain (parametric uncertainty); and (ii) the simplified models at stake summarize phenomena that are by nature complex and non-linear in a few, sometimes linear, equations so that structural uncertainty is also a major issue. The use of robust optimization allows us to identify economic energy transition pathways under climate constraints for which the outcome scenarios remain relevant for any realization of the climate parameters. In this sense, transition pathways are made robust. We find that the abatement strategies are quite different between the two temperature targets. The most stringent one is reached by investing massively in carbon removal technologies such as bioenergy with carbon capture and storage (BECCS) which have yields much lower than traditional fossil fuelled technologies.
Forecasting of Natural Gas Consumption in Poland Based on ARIMA-LSTM Hybrid Model
Authors: Manowska Anna , Rybak Aurelia , Dylong Artur , Pielot Joachim
Published: December 2021

Natural gas is one of the main energy sources in Poland and accounts for about 15% of the primary energy consumed in the country. Poland covers only 1/5 of its demand from domestic deposits. The rest is imported from Russia, Germany, Norway, the Czech Republic, Ukraine, and Central Asia. An important issue concerning the market of energy resources is the question of the direct impact of the prices of energy resources on the income of exporting and importing countries. It should also be remembered that unexpected and large fluctuations are detrimental to both exporters and importers of primary fuels. The article analyzes natural gas deposits in Poland, raw material trade and proposes a model for forecasting the volume of its consumption, which takes into account historical consumption, prices of energy resources and assumptions of Poland’s energy policy until 2040. A hybrid model was built by combining ARIMA with LSTM artificial neural networks. The validity of the constructed model was assessed using ME, MAE, RMSE and MSE. The average percentage error is 2%, which means that the model largely represents the real gas consumption course. The obtained forecasts indicate an increase in consumption by 2040.
Combined NOx and NH3 Slip Reduction in a Stoker Boiler Equipped with the Hybrid SNCR + SCR System FJBS+
Authors: Wejkowski Robert , Kalisz Sylwester , Garbacz Przemysław , Maj Izabella
Published: December 2021

The application of secondary NOx control methods in medium to low-capacity furnaces is a relatively new topic on the energy market and thus requires further research. In this paper, the results of full-scale research of SNCR and hybrid SNCR + SCR methods applied into a 29 MWth solid fuel fired stoker boiler is presented. The tests were performed for a full range of boiler loads, from 33% (12 MWth) to 103% (30 MWth) of nominal load. A novel SNCR + SCR hybrid process was demonstrated based on an enhanced in-furnace SNCR installation coupled with TiO2-WO3-V2O5 catalyst, which provides extra NOx reduction and works as an excess NH3 “catcher” as well. The performance of a brand-new catalyst was evaluated in comparison to a recovered one. The emission of NOx was reduced below 180 mg NOx/Nm3 at 6% O2, with ammonia slip in flue gas below 10 mg/Nm3. Special attention was paid to the analysis of ammonia slip in combustion products: flue gas and fly ash. An innovative and cost-effective method of ammonia removal from fly ash was presented and tested. The main idea of this method is fly ash recirculation onto the grate. As a result, ammonia content in fly ash was reduced to a level below 6.1 mg/kg.
Intelligent Service Selection in a Multi-Dimensional Environment of Cloud Providers for Internet of Things Stream Data through Cloudlets
Authors: Milani Omid , Motamedi Seyyed , Sharifian Saeed , Nazari-Heris Morteza
Published: December 2021

The expansion of Internet of Things (IoT) services and the huge amount of data generated by different sensors signify the importance of cloud computing services such as Storage as a Service more than ever. IoT traffic imposes such extra constraints on the cloud storage service as sensor data preprocessing capability and load-balancing between data centers and servers in each data center. Furthermore, service allocation should be allegiant to the quality of service (QoS). In the current work, an algorithm is proposed that addresses the QoS in storage service allocation. The proposed hybrid multi-objective water cycle and grey wolf optimizer (MWG) considers different QoS objectives (e.g., energy, processing time, transmission time, and load balancing) in both the fog and cloud Layers, which were not addressed altogether. The MATLAB script is used to simulate and implement our algorithms, and services of different servers, e.g., Amazon, Dropbox, Google Drive, etc., are considered. The MWG has 7%, 13%, and 25% improvement, respectively, in comparison with multi-objective water cycle algorithm (MOWCA), k-means based GA (KGA), and non-dominated sorting genetic algorithm (NSGAII) in metric of spacing. Moreover, the MWG has 4%, 4.7%, and 7.3% optimization in metric of quality in comparison to MOWCA, KGA, and NSGAII, respectively. The new hybrid algorithm, MWG, not only yielded to the consideration of three objectives in service selection but also improved the performance compared to the works that considered one or two objective(s). The overall optimization shows that the MWG algorithm has 7.8%, 17%, and 21.6% better performance than MOWCA, KGA, and NSGAII in the obtained best result by considering different objectives, respectively.
Energy Storage Economic Optimization Scheduling Method for Multi-Scene Demand of Peak and Frequency Modulation
Authors: Wei Wen , Wang Yali , Dai Shuangfeng , Chen Changqing , Chen Lei
Published: December 2021

Energy storage (ES) only contributes to a single-scene (peak or frequency modulation (FM)) control of the power grid, resulting in low utilization rate and high economic cost. Herein, a coordinated control method of peak modulation and FM based on the state of ES under different time scales is proposed. Firstly, for monotone peak and FM control scenarios, the ES configuration and scheduling model is constructed with the goal of maximizing net profit. Secondly, to further improve the ES utilization rate and optimize the operating cost of ES, a cooperative control method of peak modulation and FM is proposed. This method can realize the switch between peak modulation and FM control of ES and improve the ES utilization rate and system economy. Finally, the simulation results show that, compared with that of mono-peak and single-FM control, the ES efficiency of the peak-FM multiscenario optimization scheduling method is improved by 16.25% and 37.29%, respectively. The annual net income is increased by €28,021.50, the investment recovery period is shortened by 0.27 years, and the ES configuration economy is effectively improved.
Investments in Croatian RES Plants and Energy Efficient Building Retrofits: Substitutes or Complements?
Authors: Mikulić Davor , Keček Damira
Published: December 2021

Croatian energy strategy defines ambitious goals aimed at achieving energy transition toward a sustainable low-carbon society. Achieving those goals requires significant investments in the renewable energy sources and improved energy efficiency of buildings. The purpose of this paper is to estimate and compare the economic effects of the energy transition on the renewable energy supply and demand side. The estimation of the energy transition effects in Croatia in the period 2020–2050 is based on the input-output model, which identifies direct, indirect and induced effects of investments in renewable energy sources and energy efficient buildings renovation. Results of the study reveal relatively higher gross value added and employment effects induced by investments in building retrofits, but the effects of investments in renewable energy are also significant. Investments in sustainable, efficient and environmentally effective energy system could significantly contribute to Croatian GDP. While GVA effects range from 0.4% to 0.6% of annual GDP, the share of full-time equivalent jobs induced by energy transition could reach 0.5% to 1% of total employment in Croatia. Investments in RES plants and energy efficient building reconstruction are not substitutes but complements which ensure a smooth energy transition if undertaken together.
Optimal Control of Smart Distributed Power and Energy Systems
Authors: Ferro Giulio , Robba Michela , Sacile Roberto
Published: December 2021

The increase in intermittent renewable energy resources and distributed generation has led to the need for developing new controllers and management techniques for smart grids [...]
Benefits of Low Electron-Affinity Material as the N-Type Layer for Cu(In,Ga)S2 Solar Cell
Authors: Egyna Dwinanri , Nakada Kazuyoshi , Yamada Akira
Published: December 2021

Despite the potential in single- and multi-junction solar cells application, research into the wide band gap CuIn1−xGax(Se1−ySy)2 or CIG(SSe)2 solar cell material, with Eg≥1.5eV, has yet to be extensively performed to date. In this work, we conducted a numerical study into the role of the n-type layers in CIG(SSe)2 heterojunction solar cells, specifically concerning the maximum open-circuit voltage of the devices. In the first part of the study, we derived a new ideal open-circuit voltage equation for a thin-film heterojunction solar cell by taking into account the current contribution from the depletion region. The accuracy of the new equation was validated through a simulation model in the second part of the study. Another simulation model was also used to clarify the design rules of the n-type layer in a wide band gap CIG(SSe)2 solar cell. Our work stressed the importance of a positive conduction band offset on the n-/p-type interface, through the use of a low electron affinity n-type material for a solar cell with a high open-circuit voltage. Through a precise selection of the window layer material, a buffer-free CIG(SSe)2 design is sufficient to fulfill such conditions. We also proposed the specific roles of the n-type layer, i.e., as a passivation layer and selective electron contact, in the operation of CIGS2 solar cells.
Assessment of Wind and Solar Hybrid Energy for Agricultural Applications in Sudan
Authors: Khan Zafar A. , Imran Muhammad , Altamimi Abdullah , Diemuodeke Ogheneruona E. , Abdelatif Amged Osman
Published: December 2021

In addition to zero-carbon generation, the plummeting cost of renewable energy sources (RES) is enabling the increased use of distributed-generation sources. Although the RES appear to be a cheaper source of energy, without the appropriate design of the RES with a true understanding of the nature of the load, they can be an unreliable and expensive source of energy. Limited research has been aimed at designing small-scale hybrid energy systems for irrigation pumping systems, and these studies did not quantify the water requirement, or in turn the energy required to supply the irrigation water. This paper provides a comprehensive feasibility analysis of an off-grid hybrid renewable energy system for the design of a water-pumping system for irrigation applications in Sudan. A systematic and holistic framework combined with a techno-economic optimization analysis for the planning and design of hybrid renewable energy systems for small-scale irrigation water-pumping systems is presented. Different hybridization cases of solar photovoltaic, wind turbine and battery storage at 12 different sites in Sudan are simulated, evaluated, and compared, considering the crop water requirement for different crops, the borehole depth, and the stochasticity of renewable energy resources. Soil, weather, and climatic data from 12 different sites in Sudan were used for the case studies, with the key aim to find the most robust and reliable solution with the lowest system cost. The results of the case studies suggest that the selection of the system is highly dependent on the cost, the volatility of the wind speed, solar radiation, and the size of the system; at present, hybridization is not the primary option at most of sites, with the exception of two. However, with the reduction in price of wind technology, the possibility of hybrid generation will rise.
Comparison of Interleaving Methods of Parallel Connected Three-Level Bi-Directional Converters
Authors: Kim Hae-In , Kim Su-Hwan , Baek Seung-Woo , Kim Hag-Wone , Cho Kwan-Yuhl , Kim Gil-Dong
Published: December 2021

The voltage and current ripples in the three-level bi-directional converter (TLBC) can be reduced by an interleaving technique that controls a phase difference between the modules of power converter. On the other hand, the inductor current ripple in TLBC is increased due to the circulating current between the modules. In this paper, the effects of two interleaving methods on a two-phase TLBC, Z-type and N-type, are investigated and compared. In particular, capacitor current ripple, and voltage ripple are compared by two interleaving methods verified through Powersim (PSIM) simulation.
A Case Study: Sediment Erosion in Francis Turbines Operated at the San Francisco Hydropower Plant in Ecuador
Authors: Cruzatty Cristian , Jimenez Darwin , Valencia Esteban , Zambrano Ivan , Mora Christian , Luo Xianwu , Cando Edgar
Published: December 2021

The operation of various types of turbomachines is importantly affected by sediment erosion. Francis turbines used for power generation typically suffer said effects due to the fact that they are used in sediment-laden rivers and are usually operated disregarding the long-term effect of the erosion on turbine performance. This investigation seeks to study the erosion rate for the main components of the turbines located at San Francisco hydropower plant in Pastaza, Ecuador. A sediment characterization study was performed in order to determine the properties of the particles present in Pastaza River and accurately predict their effect on the turbine flow passages. A numerical approach combining liquid–solid two-phase flow simulation and an erosion model was used to analyze the erosion rates at different operating conditions and determine wear patterns in the components. As expected, the results indicated that an increase in the erosion rate was obtained for higher intake flows. However, a dramatic increase in the erosion rate was observed when the turbine was operated at near-full-load conditions, specifically when guide vane opening exceeded a 90% aperture.
Analysis of Fire Hazards Associated with the Operation of Electric Vehicles in Enclosed Structures
Authors: Dorsz Adam , Lewandowski Mirosław
Published: December 2021

The article discusses the analysis of the possible development of hazards associated with the operation of vehicles equipped with an electric drive using the example of passenger cars. The authors review the problem of the safety of people and property resulting from the occurrence of a fire in an electric passenger car, in the context of fires that have occurred in recent years. Particular attention was paid to the analysis of the state of knowledge concerning the characteristics of the fire progression in an electric car, its heat release rate curve [HRR], total heat release [THR], heat of combustion and factors affecting the fire progression. In this paper, an attempt was made to compare the fire characteristics of an electric car and a passenger car equipped with an internal combustion engine together with an estimation, using CFD simulations, of the impact on the safety of people and property in closed structures such as underground garages or road tunnels. The need for further development of research on electric cars equipped with large lithium-ion batteries in the context of their fire safety is indicated. The authors pay attention to the insufficient amount of data available to understand the fire characteristics of modern electric cars, which would enable the appropriate design of fire safety systems in building structures.
Investigation of Distribution Transformers Vibrations in Terms of Core and Winding Condition Assessment
Authors: Gielniak Jaroslaw , Czerniak Magdalena
Published: December 2021

This work refers to the criterion values used to assess the state of the active part of the transformer based on the analysis of the effective value of the total vibration acceleration and the frequency spectrum. It was proved in the work that the criteria values should be differentiated for transformers of different rated power. Transformers with lower rated power are characterized by lower RMS values of vibration acceleration than units with higher rated power, which cannot remain without impact on the criteria values. Trend analysis of the total aRMS values may reveal increasing defects before the currently applicable criteria values are exceeded. In addition, the influence of the position of the sensor on the frequency spectrum of the obtained signals was analyzed. It was proved that the sensors should be mounted in the middle of the transformer tank, between its lower part and the cover. The dependence of RMS value of vibration acceleration on no-load losses was also determined for transformers of different types but the same rated power. This relationship will not have a large share in the total vibrations of the transformer, due to slight changes in the value of aRMS occurring for all analyzed units.
3 kW Thermoelectric Generator for Natural Gas-Powered Heavy-Duty Vehicles—Holistic Development, Optimization and Validation
Authors: Heber Lars , Schwab Julian , Knobelspies Timo
Published: December 2021

Emissions from heavy-duty vehicles need to be reduced to decrease their impact on the climate and to meet future regulatory requirements. The use of a cost-optimized thermoelectric generator based on total cost of ownership is proposed for this vehicle class with natural gas engines. A holistic model environment is presented that includes all vehicle interactions. Simultaneous optimization of the heat exchanger and thermoelectric modules is required to enable high system efficiency. A generator design combining high electrical power (peak power of about 3000 W) with low negative effects was selected as a result. Numerical CFD and segmented high-temperature thermoelectric modules are used. For the first time, the possibility of an economical use of the system in the amortization period of significantly less than 2 years is available, with a fuel reduction in a conventional vehicle topology of already up to 2.8%. A significant improvement in technology maturity was achieved, and the power density of the system was significantly improved to 298 W/kg and 568 W/dm3 compared to the state of the art. A functional model successfully validated the simulation results with an average deviation of less than 6%. An electrical output power of up to 2700 W was measured.
Public Service Obligation Levy in the Context of Energy Sustainability and Security: The Cases of Ireland, Greece, Denmark and Lithuania
Authors: Karpavicius Tomas , Balezentis Tomas
Published: December 2021

Energy policy affects the functioning of the economic and financial systems of countries worldwide. This paper provides a theoretical overview of the economy–energy nexus and discusses the particular cases of the energy policy dynamics amid the sustainability goals. This paper integrates multiple perspectives on the energy–economy nexus, with a particular focus on the energy trilemma, 4As of energy security and PESTEL approach. This allows the development of a comprehensive framework for the analysis of energy security and the sustainability interaction. A review of manifestations of the different dimensions of energy security and sustainability is carried out to identify the most topical facets of the issue. Then, the cases of the selected European Union countries (Ireland, Greece, Denmark and Lithuania) are presented to highlight the effects and features of the recent energy policy changes there. Indeed, these countries apply a PSO levy mechanism on electricity tariffs and are diverse in their geopolitical situation, economic development, geographical situation and energy dependency level. The analysis of the situations of such different countries applying the PSO levy mechanism makes it possible to perform a broader and more in-depth assessment and comparison of electricity tariff regulations. Thus, the developed theoretical model is applied to identify the major outcomes of the energy policy regimes (with a focus on tariff regulation) in the selected countries.
Analysis of Triboelectrostatic Separation Process of Mixed Poly(ethylene terephthalate) and High-Density Polyethylene
Authors: Lyskawinski Wieslaw , Baranski Mariusz , Jedryczka Cezary , Mikolajewicz Jacek , Regulski Roman , Rybarczyk Dominik , Sedziak Dariusz
Published: December 2021

The aim of this study was to investigate and analyze the separation process of poly (ethylene terephthalate) and high-density polyethylene mixture. The research studied the influence of parameters of tribocharging and separation processes on the quality of separation. The research was carried out using a developed test stand consisting of a test tribocharger and a dedicated drum-type electrostatic separator. Both the separator and the tribocharger have been designed as automated test benches to assess the quality of plastic separation. In order to assess the quality of electrostatic separation of plastics, an original method based on the use of a dedicated vision system was used. The research was conducted in two stages. Firstly, the influence of the tribocharging process parameters on the efficiency of the process, i.e., the charge collected, was investigated. The next stage of the research was focused on the analysis of the influence of the separation process parameters on its effectiveness. The obtained results were presented and discussed. On the basis of the conducted research, the parameters of the tribocharging and separation processes affecting their effectiveness were determined.