bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion-Specific and Solvent Effects on PDADMA–PSS Complexation and Multilayer Formation
Authors: Jukić Jasmina , Korade Karla , Milisav Ana-Marija , Marion Ida Delač , Kovačević Davor
Published: July 2021

Among various parameters that influence the formation of polyelectrolyte complexes and multilayers, special emphasis should be placed on ion-specific and solvent effects. In our study, we systematically examined the above-mentioned effects on poly(diallyldimethylammonium chloride) (PDADMACl)-sodium poly(4-styrenesulfonate) (NaPSS) complexation in solution and at the surface by means of dynamic light scattering, ellipsometry and atomic force microscopy measurements. As solvents, we used water and water/ethanol mixture. The obtained results confirm the importance of ion-specific and solvent effects on complexes prepared in solution, as well as on multilayers built up on a silica surface. The experiments in mixed solvent solution showed that at a higher ethanol mole fraction, the decrease in monomer titrant to titrand ratio, at which the increase in the size of complexes is observed, takes place. The difference between chloride and bromide ions was more pronounced at a higher mole fraction of ethanol and in the case of positive complex formation, suggesting that the larger amount of bromide ions could be condensed to the polycation chain. These findings are in accordance with the results we obtained for polyelectrolyte multilayers and could be helpful for designing polyelectrolyte multilayers with tuned properties needed for various applications, primarily in the field of biomedicine.
Modeling Interactions of Iron Atoms Encapsulated in Nanotubes
Authors: Alshehri Mansoor H.
Published: July 2021

The behavior and electronic structure of the carbon and boron nitride nanotubes that interact with the iron atom were studied using the Lennard–Jones potential and hybrid discrete-continuum approach. The iron-filled nanotubes were explored by means of classical applied mathematics in order to develop an understanding of the underlying mechanisms of the encapsulation of metal atoms inside nanotubes. Herein, we examined the suction energy and then the equilibrium offset positions of the iron atoms inside zigzag and armchair single-walled nanotubes, to obtain the optimal radii of the tubes and encapsulate the iron atom by determining the radii that provide the minimum interaction energies. Our observations indicate that the encapsulation behaviour depends on the radii of the nanotubes, and we predict that it is less likely for an iron atom to be enclosed inside the nanotubes when the value of the tube radius is less than ≈2.5 Å. The optimal nanotube necessary to fully enclose the iron atom has a radius of ≈4.2 for both carbon and boron nitride nanotubes, which approximately corresponds to the interaction energies of −1.8 kcal/mol. In its entirety, this work presents an approach that might further the understanding of the encapsulation of metal atoms inside nanotubes.
Investigation of CoCr Dental Alloy: Example from a Casting Workflow Standpoint
Authors: Majerič Dragana , Lazić Vojkan , Majerič Peter , Marković Aleksa , Rudolf Rebeka
Published: July 2021

Cobalt-chromium (CoCr) alloys have been used in dentistry for dental bridges, crowns and implants for decades. When using CoCr alloys, a number of fractures have occurred in the Dental Laboratory, both when handling the castings and after they have been placed in the patient’s mouth. It is assumed that the key cause of the resulting fractures of CoCr dental bridges is the casting process, which includes the preparation and mixing of the basic components of the CoCr dental alloy, unstable solidification and the final treatment of the tooth casting surface. The aim of this study was, therefore, to examine three castings differently prepared from the CoCr alloy. For the initial CoCr alloy, we selected the one supplied directly from the manufacturer; three test samples were CoCr alloy remelted four times in the same crucible, while the fourth sample was the remaining solidified alloy from the crucible, taken at the last remelting. Characterisation of the microstructure of all four samples was performed by optical and scanning electron microscopy equipped with an energy dispersive X-ray spectroscope and X-ray diffractometry. Microhardness measurements were also performed. The investigation revealed that the microstructure of the castings is composed of a CoCr alloy matrix with a eutectic interdendritic composition and interdendritic precipitates, which were rich in W and Mo. The two oxides were identified as chromium oxide with silicon content and chromium oxide, which originated from the CoCr alloy as casting residue. The high content of silicon in the chromium oxide can be attributed to the silicon oxide from the ceramic melting crucible, mixed in with the remains from the CoCr alloy melting. The second oxide showed a more regular elemental content for chromium oxide, mixed with a small quantity of impurities and the casting CoCr alloy. Based on this research, some recommendations were made for working with CoCr alloys in the Dental Laboratory, with the aim of reducing the risk of dental bridge fractures in the future.
Nanocellulose Bulk Material Prepared by Steam Treatment and Hot Press Molding: Material Processing and Machining Test
Authors: Kim Jung-Woong , Kim Hyun-Chan , Zhai Lindong , Agumba Dickens Owino , Kim Jaehwan
Published: July 2021

Nanocellulose (NC) has been spotlighted as a new building block of future materials since it has many advantages, such as being lightweight and environment-friendly and having high mechanical properties and heat resistance. However, the use of NC requires an upscale manufacturing process to maintain its advantageous properties. Herein, the process of assembling NC into a macro-scale bulk material was developed through a combination of steam treatment and hot press molding. The steam treatment was applied to an NC paste to energize the hydroxyl groups in the cellulose, followed by two stages of hot press molding, which helped in the self-assembly of NC without adhesives. Cellulose nanocrystals were used as the NC, and circular disk shape specimens were prepared. The mechanical properties of the prepared bulk material were higher than typical engineering plastics. In addition, an end mill machining test of the NC bulk material showed its machinability. This paper showed the processing feasibility of NC bulk material, which can substitute plastics.
Le Corbusier’s Urban Planning as a Cultural Legacy. An Approach to the Case of Chandigarh
Authors: Rodríguez-Lora Juan-Andrés , Rosado Ana , Navas-Carrillo Daniel
Published: July 2021

The uniqueness and importance of Le Corbusier’s work were ratified by the recognition and inclusion of 17 of his projects as heritage legacy on UNESCO’s (The United Nations Educational, Scientific and Cultural Organization) World Heritage List in 2016. Despite the disciplinary diversity of his entire career, it is his architectural work that enjoys the greatest levels of dissemination and recognition. Consequently, it is assumed that Le Corbusier’s architectural work is more protected than its urban plans. This article aims to advance the recognition of the latter. To this end, it proposes a cartographic and documentary review of his projects, a specialized bibliographic review, as well as a review of national and international databases on his built work. Of 88 built works, at least 51 have some kind of heritage protection. In any case, less attention is paid to the urban dimension of his work. The city of Chandigarh presents a series of particularities, apart from being the only Corbusierian city built, which could raise the need for its safeguarding and recognition as a cultural legacy. 20th-century urban planning, and Chandigarh in particular, require the application of criteria complementary to those usually applied in heritage protection in object-based approaches.
A Novel Approach to Classification and Reporting of Lymph Node Fine-Needle Cytology: Application of the Proposed Sydney System
Authors: Vigliar Elena , Acanfora Gennaro , Iaccarino Antonino , Mascolo Massimo , Russo Daniela , Scalia Giulia , Della Pepa Roberta , Bellevicine Claudio , Picardi Marco , Troncone Giancarlo
Published: July 2021

Fine-needle cytology (FNC) is a useful diagnostic tool in the first line evaluation of lymphadenopathy of unknown aetiology. Nevertheless, considering the large number of conditions presenting as lymphadenopathy, lymph node cytology represents a challenging scenario. Recently, an expert panel published the proposal of the Sydney system for performing classification and reporting of lymph node cytopathology; the aim of the present study was to evaluate the applicability of this system. Thus, 300 lymph node FNCs performed over 1 year were reviewed and categorized according to the Sydney system classification. Overall, n = 20 cases (6.7%) were categorized as L1-inadequate/non-diagnostic; n = 104 (34.7%) as benign (L2); n = 25 (8.3%) as atypical (L3); n = 13 (4.3%) as suspicious (L4), and n = 138 (46%) as malignant (L5). FNC diagnoses were correlated with histopathologic and clinical follow-up to assess the diagnostic accuracy and the risk of malignancy (ROM) for each diagnostic category. Statistical analysis showed the following results: sensitivity 98.47%, specificity 95.33%, positive predictive value 96.27%, negative predictive value 98.08%, and accuracy 97.06%. The ROM was 50% for the category L1, 1.92% for L2, 58.3% for L3, and 100% for L4 and L5. In conclusion, FNC coupled with ancillary techniques ensures satisfactory diagnostic accuracy and the implementation of the Sydney system may improve the practice of cytopathologists.
Large Platelet and Endothelial Extracellular Vesicles in Cord Blood of Preterm Newborns: Correlation with the Presence of Hemolysis
Authors: Hujacova Andrea , Sirc Jan , Pekarkova Kristyna , Brozova Tereza , Kostelanska Marie , Soukup Jakub , Mosko Tibor , Holada Karel , Stranak Zbynek
Published: July 2021

Different biomarkers are investigated to detect the causes of severe complications in preterm infants. Extracellular vesicles (EVs) are recognized as an important part of cell-to-cell communication, and their increased levels were reported in numerous pathological states. We aimed to increase our knowledge about the incidence of platelet and endothelial EVs in cord blood of preterm newborns using conventional flow cytometry. The presence of platelet (CD36+CD41+), activated platelet (CD41+CD62+), and endothelial (CD31+CD105+) EVs was analyzed. Immune electron microscopy was used to confirm the presence of EVs and the specificity of their labeling. The size of detected extracellular vesicles was in the range 400–2000 nm. The differences in the counts of EVs between the preterm and control group were not significant and no correlation of EVs count with gestation age was recorded. Cord blood plasma samples with free hemoglobin level > 1 mg/mL had more than threefold higher counts of CD36+CD41+ and CD41+CD62+ EVs (p < 0.001), while the count of CD31+CD105+ EVs was only moderately increased (p < 0.05). Further studies utilizing cytometers with improved sensitivity are needed to confirm that the analysis of large platelet and endothelial EVs mirrors the quantitative situation of their whole plasma assemblage.
Development and Validation of a Radiomics Nomogram for Differentiating Mycoplasma Pneumonia and Bacterial Pneumonia
Authors: Li Honglin , Li Ting , Cai Qinxin , Wang Xiaozhuan , Liao Yuting , Cheng Yuanxiong , Zhou Quan
Published: July 2021

Objectives: To develop and validate a radiological nomogram combining radiological and clinical characteristics for differentiating mycoplasma pneumonia and bacterial pneumonia with similar CT findings. Methods: A total of 100 cases of pneumonia patients receiving chest CT scan were retrospectively analyzed, including 60 patients with mycoplasma pneumonia and 40 patients with bacterial pneumonia. The patients were divided into the train set (n = 70) and the test set (n = 30). The features were extracted from chest CT images of each patient by AK analysis software, then univarite analysis, spearman correlation analysis, and least absolute shrinkage and selection operator (LASSO) were utilized for dimension reduction in training set. A radiomics model was built by multivariable logistic regression based on the selected features, and a radiomics-clinical multivariable logistic regression model was built by combining imaging radiomics and clinical risk factors (age and temperature). ROC, AUC, sensitivity, specificity, and accuracy were calculated to validate the two models. The nomogram of the radiomics-clinical was built and evaluated by calibration curve. The clinical benefit of the two models was measured by using decision curve. Results: A total of 396 texture features were extracted from each chest CT image, and 10 valuable features were screened out. In the radiomics model, the AUC, sensitivity, specificity, and accuracy for the train set is 0.877, 0.762, 0.821, 78.6%, and for the test set it is 0.810, 0.667, 0.750 and 70.0%, respectively. In the radiomics-clinical model, the AUC, sensitivity, specificity, and accuracy for the train set is 0.905, 0.976, 0.714, 87.1%, and for the test set is is 0.847, 0.889, 0.667 and 80.0%, respectively. Decision curve analysis shows that both the two models increase the clinical benefits of the patients, and the radiomics-clinical model gains higher clinical benefits, compared to the radiomics model. Conclusion: The radiomics-clinical nomogram had good performance in identifying mycoplasma pneumonia and bacterial pneumonias, which would be helpful in clinical decision-making.
Characterization of the Diagnostic Performance of a Novel COVID-19 PETIA in Comparison to Four Routine N-, S- and RBD-Antigen Based Immunoassays
Authors: Spaeth Alexander , Masetto Thomas , Brehm Jessica , Wey Leoni , Kochem Christian , Brehm Martin , Peter Christoph , Grimmler Matthias
Published: July 2021

In 2019, a novel coronavirus emerged in Wuhan in the province of Hubei, China. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) quickly spread across the globe, causing the neoteric COVID-19 pandemic. SARS-CoV-2 is commonly transmitted by droplet infection and aerosols when coughing or sneezing, as well as high-risk exposures to infected individuals by face-to-face contact without protective gear. To date, a broad variety of techniques have emerged to assess and quantify the specific antibody response of a patient towards a SARS-CoV-2 infection. Here, we report the first comprehensive comparison of five different assay systems: Enzyme-Linked Immunosorbent Assay (ELISA), Chemiluminescence Immunoassay (CLIA), Electro-Chemiluminescence Immunoassay (ECLIA), and a new Particle-Enhanced Turbidimetric Immunoassay (PETIA) for SARS-CoV-2. Furthermore, we also evaluated the suitability of N-, S1- and RBD-antigens for quantifying the SARS-CoV-2 specific immune response. Linearity and precision, overall sensitivity and specificity of the assays, stability of samples, and cross-reactivity of general viral responses, as well as common coronaviruses, were assessed. Moreover, the reactivity of all tests to seroconversion and different sample matrices was quantified. All five assays showed good overall agreement, with 76% and 87% similarity for negative and positive samples, respectively. In conclusion, all evaluated methods showed a high consistency of results and suitability for the robust quantification of the SARS-CoV-2-derived immune response.
Synchronous Thyrolipoma and Papillary Thyroid Carcinoma: A Rare but Significant Event
Authors: Kuk Mariya , Kuo Chu-Jen , Nguyen Van-Hung , Chen Chien-Chin
Published: July 2021

The presence of adipocytes within thyroid glands is a rare finding seen in thyrolipoma, diffuse lipomatosis, or thyroid teratoma. Although some cases present with multinodular goiter or autoimmune thyroiditis, the exact cause has not yet been elucidated. Among reported cases, thyrolipomas mainly occur in females and usually present as a solitary lesion. However, a few reported cases had coexisting papillary thyroid carcinomas. Herein, we present a 51-year-old female with synchronous thyrolipoma (2.0 × 1.5 × 1.3 cm) and papillary thyroid carcinoma (0.7 × 0.6 × 0.6 cm) within the same thyroid lobe. She had diabetes mellitus and hypertension and complained of anterior neck enlargement and discomfort for three months. Thyroid sonography showed multiple hypoechoic nodules, one of which was heterogeneous and ill-defined. Fine needle aspirate cytology for the ill-defined nodule was suspicious for papillary thyroid carcinoma. She subsequently received radical thyroidectomy and neck lymph node dissection. Histopathologically, one thyrolipoma and one papillary thyroid carcinoma were identified in the right lobe of the thyroid gland without metastases of lymph nodes, while other nodules were multinodular goiter. Notably, thyrolipoma may not be simply an incidental finding but might coexist with thyroid carcinomas. A brief review of the pertinent literature of prior reports is also provided.
Does Adding Standard Systematic Biopsy to Targeted Prostate Biopsy in PI-RADS 3 to 5 Lesions Enhance the Detection of Clinically Significant Prostate Cancer? Should All Patients with PI-RADS 3 Undergo Targeted Biopsy?
Authors: Gomez-Gomez Enrique , Moreno Sorribas Sara , Valero-Rosa Jose , Blanca Ana , Mesa Juan , Salguero Joseba , Carrasco-Valiente Julia , López-Ruiz Daniel , Anglada-Curado Francisco José
Published: July 2021

Introduction. Our aim was to assess the value of adding standard biopsy to targeted biopsy in cases of suspicious multiparametric magnetic resonance imaging (mp-MRI) and also to evaluate when a biopsy of a PI-RADS 3 lesion could be avoided. Methods: A retrospective study of patients who underwent targeted biopsy plus standard systematic biopsy between 2016–2019 was performed. All the 1.5 T magnetic resonance images were evaluated according to PI-RADSv.2. An analysis focusing on the clinical scenario, lesion location, and PI-RADS score was performed. Results. A total of 483 biopsies were evaluated. The mean age was 65 years, with a PSA density of 0.12 ng/mL/cc. One-hundred and two mp-MRIs were categorized as PI-RADS-3. Standard biopsy was most helpful in detecting clinically significant prostate cancer (csPCa) in patients in the active surveillance (AS) cohort (increasing the detection rate 12.2%), and in peripheral lesions (6.5%). Adding standard biopsy showed no increase in the detection rate for csPCa in patients with PI-RADS-5 lesions. Considering targeted biopsy in patients with PI-RADS 3 lesions, a higher detection rate was shown in biopsy-naïve patients versus AS and in patients with a previous negative biopsy (p = 0.002). Furthermore, in these patients, the highest rate of csPCa detection was in anterior lesions [42.9% (p = 0.067)]. Conclusions. Our results suggest that standard biopsy could be safely omitted in patients with anterior lesions and in those with PI-RADS-5 lesions. Targeted biopsy for PI-RADS-3 lesions would be less effective in peripheral lesions with a previous negative biopsy.
The Morphological and Dynamic Changes of Ultrasound in the Evaluation of Effects of Oral Steroids Treatment for Patients with Carpal Tunnel Syndrome
Authors: Yau Yun-Chain , Yang Chun-Pai , Lin Ching-Po , Tsai I-Ju , Chang Ching-Mao , Yang Cheng-Chia , Shih Po-Hsuan , Liao Yin-Yin
Published: July 2021

The role of oral steroids in carpal tunnel syndrome (CTS) remains elusive. This study aims to depict the ultrasound findings and conceivable mechanisms in relation to the efficacy of oral steroids for patients with CTS by measuring the morphological and motion changes in the median nerve. In this study, CTS patients were randomized to the oral steroid group (14 participants and 22 wrists) or nicergoline group (22 participants and 35 wrists) for 4 weeks. Both treatment arms were given global symptom score (GSS) measurements and completed an ultra-sound at baseline and at 2- and 4-weeks post-treatment. In the nerve conduction study (NCS), distal motor latency (DML) was used to assess the treatment response at baseline and 4 weeks post-treatment. The cross-sectional area (CSA) and amplitude (AMP) evaluated by the maximum lateral sliding displacement represented the morphological and dynamic changes in the median nerve, respectively. The results showed that AMP, CSA, GSS, and DML were significantly im-proved in the steroid group, as compared to the nicergoline group at weeks 2 and 4 (p < 0.05). The mean improvement in ultrasound parameters CSA (15.03% reduction) and AMP (466.09% increase) was better than the DML (7.88% reduction) parameter of NCS, and ultrasound changes were detectable as early as 2 weeks after oral steroid administration. Ultrasounds can serve as a tool for the quantitative measurement of treatment effects and can potentially elucidate the pathogenesis of CTS in a non-invasive and more effective manner.
The Correlation of the IETA Ultrasound Score with the Histopathology Results for Women with Abnormal Bleeding in Western Romania
Authors: Furau Alexandru Marius , Toma Mirela Marioara , Ionescu Cringu , Furau Cristian , Bungau Simona , Dimitriu Mihai , Tit Delia Mirela , Furau Gheorghe , Petre Izabella , Craina Marius
Published: July 2021

In the early differential diagnosis of endometrial cancer (EC), decisive and mandatory histological aspects are considered, in addition to obvious clinical manifestations. In addition, sonographic aspects are characteristic in relation to the stage, degree, and histological types of identified cancer. This bi-center retrospective observational study included 594 women with abnormal uterine bleeding outside pregnancy, for which a biopsy was performed in the Obstetrics and Gynecology Departments of the Emergency County Hospitals of Arad and Timis Counties, Romania, between 2015 and 2019. Most of the cases were represented by EC or endometrial hyperplasia (EH). Of the 594 cases, 25.5% (n = 153) were EC at women aged between 41 and 85 years. High International Endometrial Tumor Analysis (IETA) scores (3, 4) were associated with a relative risk of 2.9335 compared with other endometrial lesions (95% CI 2.3046 to 3.734, p < 0.0001, NNT 1.805). Histological aspects and pelvic ultrasound using IETA scores represent valuable noninvasive assets in diagnosing and differentiating endometrial cancer from benign uterine pathology.
Publisher’s Note: Dietetics—A New Open Access Journal
Authors: Jiang Lei , Lin Shu-Kun
Published: July 2021

Eighty-eight percent of countries face the serious burden of malnutrition of either two or three forms, such as acute and/or chronic undernutrition, micronutrient deficiencies, obesity, and diet-related diseases (including type II diabetes, cardiovascular diseases, and certain types of cancer) [...]
How to Construct Polar Codes for Ring-LWE-Based Public Key Encryption
Authors: Wang Jiabo , Ling Cong
Published: July 2021

There exists a natural trade-off in public key encryption (PKE) schemes based on ring learning with errors (RLWE), namely: we would like a wider error distribution to increase the security, but it comes at the cost of an increased decryption failure rate (DFR). A straightforward solution to this problem is the error-correcting code, which is commonly used in communication systems and already appears in some RLWE-based proposals. However, applying error-correcting codes to those cryptographic schemes is far from simply installing an add-on. Firstly, the residue error term derived by decryption has correlated coefficients, whereas most prevalent error-correcting codes with remarkable error tolerance assume the channel noise to be independent and memoryless. This explains why only simple error-correcting methods are used in existing RLWE-based PKE schemes. Secondly, the residue error term has correlated coefficients leaving accurate DFR estimation challenging even for uncoded plaintext. It can be found in the literature that a tighter DFR estimation can effectively create a DFR margin. Thirdly, most error-correcting codes are not well designed for safety considerations, e.g., syndrome decoding has a nonconstant time nature. A code good at error correcting might be weak under a variety of attacks. In this work, we propose a polar coding scheme for RLWE-based PKE. A relaxed “independence” assumption is used to derive an uncorrelated residue noise term, and a wireless communication strategy, outage, is used to construct polar codes. Furthermore, some knowledge about the residue noise is exploited to improve the decoding performance. With the parameterization of NewHope Round 2, the proposed scheme creates a considerable DRF margin, which gives a competitive security improvement compared to state-of-the-art benchmarks. Specifically, the security is improved by 28.8%, while a DFR of 2−149 is achieved a for code rate pf 0.25, n=1024,q= 12,289, and binomial parameter k=55. Moreover, polar encoding and decoding have a quasilinear complexity O(Nlog2N) and intrinsically support constant-time implementations.
Evaluation of Low-Frequency Noise in MOSFETs Used as a Key Component in Semiconductor Memory Devices
Authors: Teramoto Akinobu
Published: July 2021

Methods for evaluating low-frequency noise, such as 1/f noise and random telegraph noise, and evaluation results are described. Variability and fluctuation are critical in miniaturized semiconductor devices because signal voltage must be reduced in such devices. Especially, the signal voltage in multi-bit memories must be small. One of the most serious issues in metal-oxide-semiconductor field-effect-transistors (MOSFETs) is low-frequency noise, which occurs when the signal current flows at the interface of different materials, such as SiO2/Si. Variability of low-frequency noise increases with MOSFET shrinkage. To assess the effect of this noise on MOSFETs, we must first understand their characteristics statistically, and then, sufficient samples must be accurately evaluated in a short period. This study compares statistical evaluation methods of low-frequency noise to the trend of conventional evaluation methods, and this study’s findings are presented.
Reliability Evaluation of Photovoltaic System Considering Inverter Thermal Characteristics
Authors: Li Tianyu , Tao Shengyu , Zhang Ruixiang , Liu Zhixing , Ma Lei , Sun Jie , Sun Yaojie
Published: July 2021

The reliable operation of photovoltaic (PV) power generation systems is related to the security and stability of the power grid and is the focus of current research. At present, the reliability evaluation of PV power generation systems is mostly calculated by applying the standard failure rate of each component, ignoring the impact of thermal environment changes on the failure rate. This paper will use the fault tree theory to establish the reliability assessment method of PV power plants, model the PV power plants working in the variable environment through the hardware-in-the-loop simulation system, and analyze the influence of the thermal characteristics of the inverter’s key components on the reliability of the PV power plant. Studies have shown that the overall reliability of bus capacitors, inverters, and PV power plants is reduced by 18.4%, 30%, and 18.7%, respectively, compared to when the thermal characteristics of bus capacitors are not considered. It can be seen that thermal attenuation has a great influence on the reliability of the PV power generation system.
Concrete Cracks Detection and Monitoring Using Deep Learning-Based Multiresolution Analysis
Authors: Arbaoui Ahcene , Ouahabi Abdeldjalil , Jacques Sébastien , Hamiane Madina
Published: July 2021

In this paper, we propose a new methodology for crack detection and monitoring in concrete structures. This approach is based on a multiresolution analysis of a sample or a specimen of concrete material subjected to several types of solicitation. The image obtained by ultrasonic investigation and processed by a customized wavelet is analyzed at various scales in order to detect internal cracks and crack initiation. The ultimate objective of this work is to propose an automatic crack type identification scheme based on convolutional neural networks (CNN). In this context, crack propagation can be monitored without access to the concrete surface and the goal is to detect cracks before they are visible. This is achieved through the combination of two major data analysis tools which are wavelets and deep learning. This original procedure is shown to yield a high accuracy close to 90%. In order to evaluate the performance of the proposed CNN architectures, we also used an open access database, SDNET2018, for the automatic detection of external cracks.
Word-Based Systolic Processor for Field Multiplication and Squaring Suitable for Cryptographic Processors in Resource-Constrained IoT Systems
Authors: Ibrahim Atef , Gebali Fayez
Published: July 2021

Internet of things (IoT) technology provides practical solutions for a wide range of applications, including but not limited to, smart homes, smart cities, intelligent grid, intelligent transportation, and healthcare. Security and privacy issues in IoT are considered significant challenges that prohibit its utilization in most of these applications, especially relative to healthcare applications. Cryptographic protocols should be applied at the different layers of IoT framework, especially edge devices, to solve all security concerns. Finite-field arithmetic, particularly field multiplication and squaring, represents the core of most cryptographic protocols and their implementation primarily affects protocol performance. In this paper, we present a compact and combined two-dimensional word-based serial-in/serial-out systolic processor for field multiplication and squaring over GF(2m). The proposed structure features design flexibility to manage hardware utilization, execution time, and consumed energy. Application Specific Integrated Circuit (ASIC) Implementation results of the proposed word-serial design and the competitive ones at different embedded word-sizes show that the proposed structure realizes considerable saving in the area and consumed energy, up to 93.7% and 98.2%, respectively. The obtained results enable the implementation of restricted cryptographic primitives in resource-constrained IoT edge devices such as wearable and implantable medical devices, smart cards, and wireless sensor nodes.
Statistical Model for Mobile User Positioning Based on Social Information
Authors: Bejarano-Luque Juan Luis , Toril Matías , Fernández-Navarro Mariano , Jiménez Luis Roberto , Luna-Ramírez Salvador
Published: July 2021

In spite of the vast set of measurements provided by current mobile networks, cellular operators have problems pinpointing problematic locations because the origin of such measurements (i.e., user location) is usually not registered. At the same time, social networks generate a huge amount of data that can be used to infer population density. In this work, a data-driven model is proposed to deduce the statistical distribution of connections, exploiting the knowledge of network layout and population density in the scenario. Due to the absence of GPS measurements, the proposed method combines data from radio connection traces stored in the network management system and geolocated posts from social networks. This information is enriched with user context information inferred from data traffic attributes. The method is tested with a large trace dataset from a live Long Term Evolution (LTE) network and a database of geotagged posts from social networks collected in real-time.
Space-Compliant Design of a Millimeter-Wave GaN-on-Si Stacked Power Amplifier Cell through Electro-Magnetic and Thermal Simulations
Authors: Ramella Chiara , Pirola Marco , Florian Corrado , Colantonio Paolo
Published: July 2021

The stacked power amplifier is a widely adopted solution in CMOS technology to overcome breakdown limits. Its application to compound semiconductor technology is instead rather limited especially at very high frequency, where device parasitic reactances make the design extremely challenging, and in gallium nitride technology, which already offers high breakdown voltages. Indeed, the stacked topology can also be advantageous in such scenarios as it can enhance gain and chip compactness. Moreover, the higher supply voltages and lower supply currents beneficially impact on reliability, thus making the stacked configuration an attractive solution for space applications. This paper details the design of two stacked cells, differing in their inter-stage matching strategy, conceived for space applications at Ka-band in 100 nm GaN-on-Si technology. In particular, the design challenges related to the thermal constraints posed by space reliability and to the electro-magnetic cross-talk issues that may arise at millimeter-wave frequencies are discussed. The best cell achieves at saturation, in simulation, 3 W of output power at 36 GHz with associated gain and efficiency in excess of 7 dB and 35%, respectively.
A High-Speed Parallel Architecture for Ripple Carry Adder with Fault Detection and Localization
Authors: Akbar Muhammad Ali , Wang Bo , Bermak Amine
Published: July 2021

Ripple-carry adder (RCA) is among the most common type of adder. However, it is not preferred in many applications because of its high latency. In this paper, two architectures of high-speed parallel RCA (PRCA) along with fault detection and localization are proposed, with reduced overhead as compared with carry look-ahead adder (CLA). In the proposed approach, RCA is divided into blocks, where the initial carry input for each block will be generated by a carry look-ahead logic unit. The delay is reduced by 43.81% as compared with the conventional 64-bit RCA design. The delay is further reduced by replacing the last blocks with a single RCA-based CSeA design and becomes equal to CLA if the last three blocks are replaced with CSeA. The proposed 64-bit design of PRCA and PRCA-CSeA requires 20.31% and 22.50% area overhead as compared with the conventional RCA design. Whereas, the delay-power-area product of our proposed designs is 24.66%, and 30.94% more efficient than conventional RCA designs. With self-checking, the proposed architecture of PRCA and PRCA-CSeA with multiple-fault detection requires 42.36% and 44.35% area overhead as compared with a 64-bit self-checking RCA design.
Numerical Simulation on Cooling Effect of Working Face under Radiation Cooling Mode in Deep Well
Authors: Zhang Xiaoyan , Bu Baoyun , Liu Lang , Cao Tianrun , Ke Yaping , Du Qiangqiang
Published: July 2021

Deep mining results in an increasingly serious hazard. Based on the principle of heat transfer and radiant cooling, a three-dimensional heat transfer model of the working face was established. The influence of the inlet airflow parameter, the surrounding wall temperature and other parameters on the temperature distribution of airflow along the working face were analyzed under the radiation cooling mode. The results show that the increment of airflow temperature in several sections along the working face decreases by 0.67 °C, 0.48 °C, 0.40 °C, 0.36 °C, 0.33 °C, 0.29 °C respectively. The farther away from the airflow inlet, the more obvious the cooling effect was. The airflow temperature of the working face is positively correlated with the airflow inlet temperature and the surrounding wall temperature, and is negatively correlated with the airflow velocity. The research provides a good solution for the working face cooling of deep mines, and also provides a theoretical reference for the research on the radiation cooling technology of the working face.
Intuitive Multiphase Matrix Converter Control Procedures Applied to Power-System Phase Shifters
Authors: Szczepanik Jerzy , Sieńko Tomasz
Published: July 2021

The article presents the concept of application of a multiphase matrix converter (MMC)-based device working as a phase-shifting control device in a power system. A matrix M × M multiphase converter is a simple structure incorporating M × M bidirectional switches, connecting M input phases to M output phases (a square structure is used). The device, in this research and under proposed control, is able to build M output sinusoidal-shape phases (desired output) from parts of input voltages. The proposed MMC-based device can be considered as a new flexible AC transmission system (FACTS) apparatus. Three basic control systems that enabled the creation of output waveforms as the combination of input ones were presented. Both 6 × 6 and 12 × 12 matrix structures were introduced, since 3 × 6 and 3 × 12 transformers are already in use. The mathematical, Simulink, and laboratory models were built to extract characteristic features of the MMC. The chosen “area-based” control procedure was based on finding a common point of area representing a certain switch (connecting a certain input and a certain output) and a time-dependent trajectory. Practical application of the MMC in a power system involves not only MMC analysis, but also the study of application requirements, possible converter topologies, and the development of new, reliable control algorithms. Particular consideration was given to the simplicity of the control and the analysis of the converter properties. The proposed control procedure did not use the PWM technique, but created output in similar way to a multilevel converter.
Energy and Exergy Analysis of the Air Source Transcritical CO2 Heat Pump Water Heater Using CO2-Based Mixture as Working Fluid
Authors: Wang Yikai , He Yifan , Song Yulong , Yin Xiang , Cao Feng , Wang Xiaolin
Published: July 2021

Given the large demand nowadays for domestic hot water, and its impact on modern building energy consumption, air source transcritical CO2 heat pumps have been extensively adopted for hot water production. Since their system efficiency is limited by significant irreversibility, a CO2-based mixture could offer a promising drop-in technology to overcome this deficiency without increasing system complexity. Although many CO2 blends have been studied in previously published literature, little has been presented about the CO2/R32 mixture. Therefore, a proposed mixture for use in transcritical CO2 heat pumps was analyzed using energy and exergy analysis. Results showed that the coefficient of performance and exergy efficiency variation displayed an “M” shape trend, and the optimal CO2/R32 mixture concentration was determined as 0.9/0.1 with regard to flammability and efficiency. The irreversibility of the throttling valve was reduced from 0.031 to 0.009 kW⋅kW−1 and the total irreversibility reduction was more notable with ambient temperature variation. A case study was also conducted to examine domestic hot water demand during the year. Pure CO2 and the proposed CO2 blend were compared with regard to annual performance factor and annual exergy efficiency, and the findings could provide guidance for practical applications in the future.
Fuel Economy Improvement of Urban Buses with Development of an Eco-Drive Scoring Algorithm Using Machine Learning
Authors: Kim Kibok , Park Jinil , Lee Jonghwa
Published: July 2021

Eco-drive is a widely used concept. It can improve fuel economy for different driving behaviors such as vehicle acceleration or accelerator pedal operation, deceleration or coasting while slowing down, and gear shift timing difference. The feasibility of improving the fuel economy of urban buses by applying eco-drive was verified by analyzing data from drivers who achieved high fuel efficiencies in urban buses with a high frequency of acceleration/deceleration and frequent operation. The items that were monitored for eco-drive were: rapid take-off/acceleration/deceleration, accelerator pedal gradient, coasting rate, shift indicator violation, average engine speed, over speed, and gear shifting under low-end engine speed. The monitoring method for each monitored item was set up, and an index was produced using driving data. A fuel economy prediction model was created using machine learning to determine the contribution of each index to the fuel economy. Furthermore, the contribution of each monitoring item was analyzed using the prediction model explainer. Accordingly, points (defined as the eco-drive score) were allocated for each monitoring item. It was verified that this score can represent the eco-drive characteristics based on the relationship between the score and fuel economy. In addition, it resulted in an average annual fuel economy improvement of 12.1%.
Review on Braking Energy Management in Electric Vehicles
Authors: Vodovozov Valery , Raud Zoja , Petlenkov Eduard
Published: July 2021

The adoption of electric vehicles promises numerous benefits for modern society. At the same time, there remain significant hurdles to their wide distribution, primarily related to battery-based energy sources. This review concerns the systematization of knowledge in one of the areas of the electric vehicle control, namely, the energy management issues when using braking controllers. The braking process optimization is summarized from two aspects. First, the advantageous solutions are presented that were identified in the field of gradual and urgent braking. Second, several findings discovered in adjacent fields of automation are debated as prospects for their possible application in braking control. Following the specific classification of braking methods, a generalized braking system composition is offered, and all publications are evaluated primarily in terms of their energy recovery abilities as a global target. Then, conventional and intelligent classes of braking controllers are compared. In the first category, classic PID, threshold, and sliding-mode controllers are reviewed in terms of their energy management restrictions. The second group relates to the issues of the tire friction-slip identification and braking torque allocation between the hydraulic and electrical brakes. From this perspective, several intelligent systems are analyzed in detail, especially fuzzy logic, neural network, and their numerous associations.
Novel Twofold Use of Photographic Technique for Simultaneous Flow Boiling Image Recording and Void Fraction Computation in a Mini-Channel Experiment
Authors: Płaczkowski Krzysztof , Grabowski Mirosław , Poniewski Mieczysław E.
Published: July 2021

The paper presents a novel twofold use of the photographic technique for flow boiling heat transfer investigation in the horizontal mini-channel. The dedicated measurement system was constructed to record basic thermal and flow parameters, i.e., boiling liquid inlet and outlet temperatures and pressures, and also temperatures inside the heating block to calculate heat flux going into the liquid. A high-speed video camera equipped with synchronous movement system was applied to combine the recording of two-phase flow images with simultaneous local void fraction measurements both based on the same photographic data set. The data were collected, managed, and refined with the scripts developed in the MathWorks Matlab 2019b environment. The synchronous use of two intelligent techniques in the scripts, i.e., the background subtraction technique and the statistical analysis of individual pictures allowed obtaining reliable experimental results. The proposed method of the void fraction determination ensures high measurement accuracy.
Co-Design Optimization of Direct Drive PMSGs for Offshore Wind Turbines Based on Wind Speed Profile
Authors: Dang Linh , Ousmane Samb Serigne , Sadou Ryad , Bernard Nicolas
Published: July 2021

This paper presents a new method to optimize, from a working cycle defined by torque and speed profiles, both the design and the control strategy of permanent magnet synchronous generators (PMSGs). The case of a 10 MW direct-drive permanent magnet generator for an Offshore wind turbine was chosen to illustrate this method, which is based on the d–q axis equivalent circuit model. It allows to optimize, with a reduced computation time, the design, considering either a flux weakening control strategy (FW) or a maximum torque per Ampere control (MTPA) strategy, while respecting all the constraints—particularly the thermal constraint, which is characterized by a transient regime. The considered objective is to minimize the mass and the average electric losses over all working points. Thermal and magnetic analytical models are validated by a 2D finite element analysis (FEA).
A Review on Numerical Approach to Achieve Building Energy Efficiency for Energy, Economy and Environment (3E) Benefit
Authors: Raj Binju P , Meena Chandan Swaroop , Agarwal Nehul , Saini Lohit , Hussain Khahro Shabir , Subramaniam Umashankar , Ghosh Aritra
Published: July 2021

Increasing energy demand in buildings with a 40% global share and 30% greenhouse gas emissions has accounted for climate change and a consequent crisis encouraging improvement of building energy efficiency to achieve the combined benefit of energy, economy, and environment. For an efficient system, the optimization of different design control strategies such as building space load, occupancy, lighting, and HVAC becomes inevitable. Therefore, interdisciplinary teamwork of developers, designers, architects, and consumers to deliver a high-performance building becomes essential. This review aims to endorse the importance of Building Performance Simulation in the pre-design phase along with the challenges faced during its adaptation to implementation. A morphology chart is structured to showcase the improvement in Building Energy Efficiency by implementing Building Performance Simulation for different building energy systems and by implementing various energy efficiency strategies to achieve the 3E benefit. As a developing nation, India still lacks mass application of Building Performance Simulation tools for improving Building Energy Efficiency due to improper channelizing or implementation; thus, this framework will enable the designers, architects, researchers to contemplate variable building energy optimization scenarios.
Study on Mineral Compositions of Direct Carbonated Steel Slag by QXRD, TG, FTIR, and XPS
Authors: Wang Xue , Ni Wen , Li Jiajie , Zhang Siqi , Li Keqing
Published: July 2021

Steel slag CO2 sequestration helps mitigate global warming and decrease the stockpile of steel slag (SS). Through orthogonal design tests and single-factor tests, this paper evaluated the effects of the water/solid mass ratio (w/s), gypsum ratio (G/SS), molding pressure, and curing duration on uniaxial compressive strength (UCS) and CO2 uptake of the compacts. The results indicated that high w/s enhanced both strength and CO2 capture ability. The proper addition of gypsum helps promote UCS increase and CO2 uptake of steel slag. In addition, increasing the molding pressure can significantly improve UCS without reducing CO2 uptake. The optimum conditions in the study were a w/s of 0.20, G/SS of 1/16, and molding pressure of 27 MPa, under which conditions 1 d UCS and CO2 uptake were 55.30 MPa and 12.36%, respectively. Microanalyses showed that gypsum activates mainly mayenite in steel slag. An increase in water addition also increased the hydration and carbonation products greatly, and the strengthened molding pressure had a significant densification effect on micro-pore structures. The study gives guidance in the application of steel slag in CO2 capture and manufacturing green construction material.