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Author(s):  
Julio Villalba ◽  
Javier Hormigo

AbstractThis article proposes a family of high-radix floating-point representation to efficiently deal with floating-point addition in FPGA devices with no native floating-point support. Since variable shifter implementation (required in any FP adder) has a very high cost in FPGA, high-radix formats considerably reduce the number of possible shifts, decreasing the execution time and area highly. Although the high-radix format produces also a significant penalty in the implementation of multipliers, the experimental results show that the adder improvement overweights the multiplication penalty for most of the practical and common cases (digital filters, matrix multiplications, etc.). We also provide the designer with guidelines on selecting a suitable radix as a function of the ratio between the number of additions and multiplications of the targeted algorithm. For applications with similar numbers of additions and multiplications, the high-radix version may be up to 26% faster and even having a wider dynamic range and using higher number of significant bits. Furthermore, thanks to the proposed efficient converters between the standard IEEE-754 format and our internal high-radix format, the cost of the input/output conversions in FPGA accelerators is negligible.


Author(s):  
Lagerstrand Kerstin ◽  
Hebelka Hanna ◽  
Brisby Helerna

Abstract Purpose It is suggested that non-specific low back pain (LBP) can be related to nerve ingrowth along granulation tissue in disc fissures, extending into the outer layers of the annulus fibrosus. Present study aimed to investigate if machine-learning modelling of magnetic resonance imaging (MRI) data can classify such fissures as well as pain, provoked by discography, with plausible accuracy and precision. Methods The study was based on previously collected data from 30 LBP patients (age = 26–64 years, 11 males). Pressure-controlled discography was performed in 86 discs with pain-positive discograms, categorized as concordant pain-response at a pressure ≤ 50 psi and for each patient one negative control disc. The CT-discograms were used for categorization of fissures. MRI values and standard deviations were extracted from the midsagittal part and from 5 different sub-regions of the discs. Machine-learning algorithms were trained on the extracted MRI markers to classify discs with fissures extending into the outer annulus or not, as well as to classify discs as painful or non-painful. Results Discs with outer annular fissures were classified in MRI with very high precision (mean of 10 repeated testings: 99%) and accuracy (mean: 97%) using machine-learning modelling, but the pain model only demonstrated moderate diagnostic accuracy (mean accuracy: 69%; precision: 71%). Conclusion The present study showed that machine-learning modelling based on MRI can classify outer annular fissures with very high diagnostic accuracy and, hence, enable individualized diagnostics. However, the model only demonstrated moderate diagnostic accuracy regarding pain that could be assigned to either a non-sufficient model or the used pain reference.


Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1482
Author(s):  
Shaopeng Yang ◽  
Peifeng Cheng ◽  
Fangzhong Hu ◽  
Wenchao Yu ◽  
Chi Zhang ◽  
...  

As research of the high cycle fatigue of carburized gear steel could not meet the status quo of longer and longer service lives, research of very high cycle fatigue (VHCF) performance has become the focus of current research. The VHCF properties of case-hardening steel 18CrNiMo7-6 after being carburized with gradient hardness distribution were investigated by means of ultrasonic fatigue tests. The results showed that the carburized specimens with a case hardness of 705 HV and core hardness of 530 HV showed VHCF phenomenon, and the fatigue lives continuously increased to even 109 cycles as the stress amplitude decreased to about 500 MPa. Observations of the fracture surfaces of the fatigue specimens showed that the fatigue crack initiation sites were located in the transition area with the hardness at about 580 HV. It was found that the transition area had low VHCF properties, since the core did not show VHCF phenomenon, and the case had a higher hardness. A fine microstructure was observed in the granular bright facet (GBF) area, and the stress intensity factor ΔKGBF was measured to be 3.04 MPam−1/2. The 109 cycles fatigue life was predicted based on the inclusion size, and the 1010 cycles fatigue life was 490 MPa based on the prediction model.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260575
Author(s):  
AbdulAzeez A. Anjorin ◽  
Ismail A. Odetokun ◽  
Ajibola I. Abioye ◽  
Hager Elnadi ◽  
Mfon Valencia Umoren ◽  
...  

The economic and humanistic impact of COVID-19 pandemic is enormous globally. No definitive treatment exists, hence accelerated development and approval of COVID-19 vaccines, offers a unique opportunity for COVID-19 prevention and control. Vaccine hesitancy may limit the success of vaccine distribution in Africa, therefore we assessed the potentials for coronavirus vaccine hesitancy and its determinants among Africans. An online cross-sectional African-wide survey was administered in Arabic, English, and French languages. Questions on demographics, self-reported health status, vaccine literacy, knowledge and perception on vaccines, past experience, behavior, infection risk, willingness to receive and affordability of the SARS-COV-2 vaccine were asked. Data were subjected to descriptive and inferential statistics. A total of 5,416 individuals completed the survey. Approximately, 94% were residents of 34 African countries while the other Africans live in the Diaspora. Only 63% of all participants surveyed were willing to receive the COVID-19 vaccination as soon as possible and 79% were worried about its side effects. Thirty-nine percent expressed concerns of vaccine-associated infection. The odds of vaccine hesitancy was 0.28 (95% CI: 0.22, 0.30) among those who believed their risk of infection was very high, compared to those who believed otherwise. The odds of vaccine hesitancy was one-fifth (OR = 0.21, 95% CI: 0.16, 0.28) among those who believed their risk of falling sick was very high, compared to those who believed their risk of falling very sick was very low. The OR of vaccine hesitancy was 2.72 (95% CI: 2.24, 3.31) among those who have previously refused a vaccine for themselves or their child compared to counterparts with no self-reported history of vaccine hesitancy. Participants want the vaccines to be mandatory (40%), provided free of charge (78%) and distributed in homes and offices (44%). COVID-19 vaccine hesitancy is substantial among Africans based on perceived risk of coronavirus infection and past experiences.


2021 ◽  
Vol 25 (12) ◽  
pp. 65-71
Author(s):  
A.M. Koshelkov ◽  
L.P. Mayorova

The TPH-in-soil of three functional zones (industrial, residential, agro-residential) of Khabarovsk have been studied. Areas of acceptable, low, moderately hazardous, moderate, high and very high pollution levels have been identified. It has been found that the TPH-in-soil of different urban functional areas differs significantly. For statistical processing of experimental data, the Boxplots method ("box-and-whiskers diagram") has been used. It has been proposed to switch to the median value of the aggregate sample of the TPH-in-soil in residential and agro-residential areas as the baseline data.


Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 952
Author(s):  
Dewu Yue ◽  
Ximing Rong ◽  
Shun Han ◽  
Peijiang Cao ◽  
Yuxiang Zeng ◽  
...  

Black phosphorus (BP), a single elemental two-dimensional (2D) material with a sizable band gap, meets several critical material requirements in the development of future nanoelectronic applications. This work reports the ambipolar characteristics of few-layer BP, induced using 2D transparent hexagonal boron nitride (h-BN) capping. The 2D h-BN capping have several advantages over conventional Al2O3 capping in flexible and transparent 2D device applications. The h-BN capping technique was used to achieve an electron mobility in the BP devices of 73 cm2V−1s−1, thereby demonstrating n-type behavior. The ambipolar BP devices exhibited ultrafast photodetector behavior with a very high photoresponsivity of 1980 mA/W over the ultraviolet (UV), visible, and infrared (IR) spectral ranges. The h-BN capping process offers a feasible approach to fabricating n-type behavior BP semiconductors and high photoresponse BP photodetectors.


Author(s):  
Weiqian Chi ◽  
Wenjing Wang ◽  
Chengqi Sun

Additively manufactured (AM) alloy usually inevitably contains defects during the manufacturing processor or service process. Defects, as a harmful factor, could significantly reduce the fatigue performance of materials. This paper shows that the location and introduced form of defects play an important role in high cycle and very high cycle fatigue (VHCF) behavior of selective laser melting Ti-6Al-4V alloy. S-N curve descends linearly for internal defects induced failure. While for artificial surface defects induced failure, S-N curve descends at first and then exhibits a plateau region feature. We also observed competition of interior crack initiation with the fine granular area feature in VHCF regime. The paper indicates that only the size or the stress intensity factor range of the defect is not an appropriate parameter describing the effect of defects on the fatigue crack initiation. Finally, the effect of artificial surface defects on high cycle and VHCF strength is modeled, i.e. the fatigue strength   σ, fatigue life  N and defect size area (square root of projection area of defect perpendicular to principal stress direction) is expressed as  σ = CN ( area)  for  N and  σ = CN ( area)  for  N≥N, where  C,  a and  n are constants, N is the number of cycles at the knee point.


2021 ◽  
Vol 9 (11) ◽  
pp. 431-444
Author(s):  
Gilly B. Ferrando ◽  
◽  
Jerlyn G. Balones ◽  

This study determined the mediating effect of symptoms of anxiety on the relationship between appraisal and teaching competence of teachers in elementary and secondary schools of San Isidro North and South Districts. The descriptive-correlational research design was utilized in this study employing stratified random sampling with 300 sampled teachers. Data collection was made through administration of survey questionnaires. Three sets of adapted survey questionnaires were used and were subjected for content validity and reliability test. The analysis of data was done using the Mean, Pearson-r, Multiple Regression Analysis and Medgraph using Sobel z-test. The results revealed that the level of appraisal and teaching competence of teachers were very high and the level of symptoms of anxiety was high. A positive significant relationship between appraisal and teaching competence, appraisal and symptoms of anxiety, and symptoms of anxiety and teaching competence was proven in the study. Further, the findings showed that symptoms of anxiety played a partial mediation, thus, it cannot fully account on the influence of appraisal towards teaching competence. Although teachers manifested a high level of symptoms of anxiety, still, they showed a very high level of appraisal and a very high level of teaching competence. Moreover, a high level of symptoms of anxiety did not hinder teachers capability to be very highly competent in teaching.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryan Warr ◽  
Matthew C. Jewell ◽  
Neil Mitchell ◽  
Alexander Rack ◽  
Jack Swanson ◽  
...  

AbstractTwo sections of heat-treated (HT) and non-heat-treated (NHT) Cable-in-Conduit Conductor (CICC) of a design similar to the ITER tokomak have been imaged using very high energy X-ray tomography at the ESRF beamline ID19. The sample images were collected at four temperatures down to 77 K. These results showed a greater degree of movement, bundle distortion and touching strands in the NHT sample. The HT sample showed non-linear movements with temperature especially close to 77 K; increasing non-circularity of the superconducting fibre bundles towards the periphery of the CICC, and touching bundles throughout the CICC. The images have highlighted where future design might improve potential weakness, in particular at the outer perimeters of the conductor and the individual sub-cable, ‘petal’ wraps.


2021 ◽  
Vol 1 (2) ◽  
pp. 215-219
Author(s):  
Nurul Hikmah ◽  
Nani Kurniati ◽  
Tabita Wahyu Triutami ◽  
Ulfa Lu’luilmaknun ◽  
Dwi Novitasari

This community service activity was carried out with the aim of increasing the professionalism of senior high school teachers at SMAN 7 Mataram through Classroom Action Research (CAR). This training activity is intended for teachers at SMAN 7 Mataram. The implementation of activities is presented in a workshop approach through lectures, discussions, questions and answers, and simulations. The presentation includes material on CAR, data analysis in CAR accompanied by several examples of proposal drafts and scientific publications related to CAR. The very high motivation of the participants was seen during the implementation of community service activities, in addition to the very positive response of the participants with an enthusiasm level of 90% seen during the implementation of this community service. The level of teacher satisfaction is very high with this activity and they have high hopes that further activities will be held as assistance for CAR activities in schools and are able to produce scientific papers that are worthy of publication.


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