Miracle-dz/UniFAR-FTUs huggingface dataset:
Analysis of typical working conditions and experimental research of friction stir welding robot for aerospace applications

In an attempt to address the limitations of single function and the poor process flexibility of existing friction stir welding equipment, a new friction stir welding robot has been developed to address practical problems in three-dimensional surface welding. Based on an analysis of the components of the robotic system, a kinematics model was established, and the forward and backward kinematics solutions were derived for the robot. An iterative nearest point algorithm, iterative closest point based on point cloud matching, was used to plan the welding trajectory for the most complex petal welding conditions, and an experimental study was conducted. The results show that the kinematic and dynamic test results were consistent with the acquired simulation curves for specific sizes of the rocket cap flaps under appropriate welding conditions. The normal error of the weld was less than 85 µm, the average tensile strength was 359 MPa, and the elongation was 7.20%, 78.0%, and 72.0% of 2A14-T6 aluminum alloy. The friction stir welding robot exhibited robust performance, and the proposed trajectory planning method is practical and effective. The appearance, geometric dimension, and mechanical properties of the weld achieved the expected criteria, and high-precision welding of large complex thin-walled surfaces is possible.
Effect of substrate on the properties of cold sprayed coating of WC-10Ni

ABSTRACT WC-10Ni powder was deposited on Al, Cu, and low carbon steel substrates by cold gas spray method under the process gas pressure of 15 and 35 bar. The effect of substrate on the deposition phenomenon, microstructure, and microhardness of the coatings was evaluated. The cross-section morphology of the coating was studied by the scanning electron microscopy (SEM). The pinning of WC particles caused a high strength between the coating and the substrate. Crack initiation and propagation during cold spraying process, due to the high level of cold working, was the main reason for the high level of porosity of the deposited coating on the Cu substrate. It was found that low carbon steel substrate, for its higher hardness compared to aluminium and copper, experienced minimum deformation. Moreover, the harder the substrate, the higher the microhardness and fracture toughness and the lower the porosity of the coating.
Why Do Workers Join Trade Unions?

This paper uses data from manufacturing firms in Kenya to analyse the determinants of trade unionism. Matched worker-firm data from a recent Kenya manufacturing enterprise survey is used to estimate a reduced-form probit model of union membership. The results show that the likelihood of being a union member decreases with schooling; but is higher for full-time, married, and city employees. We conclude that Kenyan workers become union members to protect job tenure and to improve working conditions. JEL Classification: J32, J51, J52
Reconstructing past hydrology of eastern Canadian boreal catchments using clastic varved sediments and hydro-climatic modeling: 160 years of fluvial inflows

Analysis of short sediment cores collected in Grand Lake, Labrador, revealed that this lake is an excellent candidate for the preservation of a laminated sediment record. The great depth of Grand Lake, the availability of fine sediments along its tributaries and its important seasonal river inflow have favoured the formation of a 160-year-long clastic varved sequence. Each varve represents 1 hydrological year. Varve formation is mainly related to spring discharge conditions with contributions from summer and autumn rainfall events. The statistically significant relation between varve parameters and the Naskaupi River discharge observations provided the opportunity to develop local hydrological reconstructions beyond the instrumental period. The combined detrital layer thickness and the particle size (99th percentile) series extracted from each varve yield the strongest correlations with instrumental data (r = 0.68 and 0.75 respectively) and have been used to reconstruct the respective Naskaupi River mean and maximum annual discharges over the 1856–2016 period. The reconstructed Qmean series suggest that high Q-mean years occurred during the 1920–1960 period, and a slight decrease in Q-mean took place during the second half of the 20th century. Independent reconstructions based on rainfall–runoff modelling of the watershed from historical reanalysis of global geopotential height fields display a significant correlation with the reconstructed Naskaupi River discharge based on varve physical parameters. The Grand Lake varved sequence contains a regional hydrological signal, as suggested by the statistically significant relation between the combined detrital layer thickness series and the observed Labrador region Q-mean series extracted from five watersheds of different sizes.
A total least squares solution to a 3D coordinate transformation parameters of large Euler angles with closure constrain

A new method for calculating three-dimensional (3D) coordinate transformation parameters of large Euler angles with closure constrain is presented. This method obtains the initial value by traditional seven-parameter model. Then we derive the closure constraint condition and linearize it. The constrained total least-squares (CTLS) approach is adopted to obtain corrected values under the closure constraint condition. A practical case study is presented to illustrate the effectiveness of this new model.
Improving primary frequency response in networked microgrid operations using multilayer perceptron‐driven reinforcement learning

Individual microgrids can improve the reliability of power systems during extreme events, and networked microgrids can further improve efficiency through resource sharing and increase the resilience of critical end-use loads. However, networked microgrid operations can be subject to large transients due to switching and end-use loads, which can cause dynamic instability and lead to system collapse. These transients are especially prevalent in microgrids with high penetrations of grid-following inverter-connected renewable energy resources, which do not provide the system inertia or fast frequency response needed to mitigate the transients. One potential mitigation is to engage the existing generator controls to reduce system voltage in response to a frequency deviation, thereby reducing load and improving primary frequency response. This study investigates the use of a reinforcement-learning-based controller trained over several switching transient scenarios to modify generator controls during large frequency deviations. Compared to previously used proportional–integral controllers, the proposed controller can improve primary frequency response while adapting to changes in system topologies and conditions.
Friction and wear performance of CrSiBCN coatings sliding against ceramic and metal counterparts in sea water

In order to optimize the counterpart material and subsequently improve the tribological properties of CrSiBCN coatings on transmission components in sea water, the friction behaviour of CrSiBCN coatings sliding against two ceramics and two metals was investigated. The overall relative index (RIo) of friction coefficient and wear rate was used as evaluation criterion. Experimental results showed that CrSiBCN/Al2O3 and CrSiBCN/brass tribopairs presented the worse tribological properties than the average level indicated as positive RIo (1.64 and 0.22). In contrast, CrSiBCN/SiC and CrSiBCN/GCr15 tribopairs presented the better tribological properties than the average level indicated as negative RIo (−1.45 and −0.39). On this basis, since the lubrication effect of the silica gel generated from the hydration of SiC, CrSiBCN/SiC tribopair exhibited both lower friction coefficient and lower coatings wear rate than the average values. It was indicated that SiC was the suitable counterpart material matching with CrSiBCN coatings in sea water.
Adaptive fusion of bright-field microscopy images acquired in different focal planes

CATANANTE, V. A. A. Adaptive fusion of bright-field microscopy images acquired in different focal planes. 2020. 129 p. Dissertação (Mestrado em Ciências – Ciências de Computação e Matemática Computacional) – Instituto de Ciências Matemáticas e de Computação, Universidade de São Paulo, São Carlos – SP, 2020. Microscopy is an extremely relevant technique related to tasks that deal with micrometric order structures. Its use dates back to the 17th century and tends to evolve in parallel with the evolution of human technological knowledge. Among the various applications, the fields of biological and health sciences stand out, which involve structures normally invisible to the naked eye. There are unavoidable differences in depth between the points of the surfaces and structures which yield out-of-focus blur to images. However, high quality is necessary in order to allow precise analysis in microscopy applications. In this sense, image quality assessment and image fusion are examples of techniques that may be applied to solve the issue. Recent works on such fields show that mathematical techniques such as frequency domain analysis, multiresolution analysis and convolutional neural networks are effective to quantitatively assess the quality of images. At the same time, researchers also present many novel techniques for image fusion, either based on classical tools such as edge detection or based on state-of-the-art machine learning frameworks. The aim of this work is to develop a two-stage method, consisting of a no-reference image quality assessment and an image fusion step, to perform the fusion of bright-field light microscopy images acquired in different focal planes, and propose novel bright-field microscopy image datasets of plant leaf histological samples as a benchmark for testing both quality assessment and fusion algorithms. Frequency domain analysis and statistical methods were used to obtain a quality metric and the energy of edges extracted with the Laplacian of Gaussian filter as the fusion rule. The mean Pearson’s correlation coefficient obtained for the image quality method was 0.7448, while the mean spatial frequency for the image fusion method was 0.0667.
Involving Stakeholders in Shaping Educational Legislation and Policy in Ukraine

The purpose of this research was to explore how effective the bottom-up approach to producing and shaping educational legislation is in Ukraine and to identify what observed changes take place in students if the bottom-up approach is simulated in the classroom. Qualitative instruments and observational data were used to yield the data. Those were a survey questionnaire, semistructured interview questionnaire, and focus group discussion observation checklists and moderators’ and facilitators’ reports. The data were processed using IBM SPSS Statistics 25.0. 0.1. Software. The results of the study suggest the bottom-up approach to shaping educational legislation can be considered an option or an alternative to the conventional law-making procedure, at least in the sphere of education, in Ukraine. The use of mock policymaking experience has proven to be an efficient teaching tool. The application of the simulation of the bottom-up approach in the courses entitled “Educational policy” and “National Education Policy” was found to have the potential to encourage students to participate in the processes of shaping education policy, legislation, and regulation. The approach accelerated the desire of the students to participate in the processes of shaping education policy, legislation, and regulation. It also brought a change to the students’ vision of the school structure, the content of education, and the way the teacher is motivated. The intervention also brought a positive change to the students’ behaviour as citizens and their motivation as teachers-to-be.
Consolidation mechanism, microstructural evolution and corrosion resistance of Inconel 625 coatings

The inter-relationships between geometrical properties, microstructural characteristics and corrosion resistance on one hand and laser-material interaction parameter (α) on the other hand are examined. A laser-material interaction parameter within the range of 599 ≤ α ≤ 400 J.s g−1 mm−1 imparted optimum characteristics of microstructure, microhardness and corrosion resistance. The consolidation mechanism of the coatings indicates that this parameter ensures the formation of a double ‘burn-in’ macrostructure into the substrate which imparts non-porous, crack-free and a fine interfacial microstructure. This study provides guidance in designing Inconel 625 coatings of desirable microstructures and corrosion resistance.
Multidisciplinary, Interdisciplinary, and Transdisciplinary (MIT) Learning Approach and Strategy Based on Indonesian National Qualification Framework (KKNI) Curriculum

Inadequate understanding and different perspectives of Islamic higher education (PTKIN) in Indonesia particularly the graduate schools towards Multidisciplinary, Interdisciplinary, and Transdisciplinary (MIT) approaches result in ineffective implementation of Indonesian National Qualification Framework/Kerangka Kualifikasi Nasional Indonesia (KKNI) curriculum. Yet, MIT approach is highly needed to accelerate state development. MIT study has integrated character which opens to new developments of science and methodology and will possibly create new knowledge hybrids. This research investigated MIT learning strategy and approach at graduate schools of UIN Syarif Hidayatullah Jakarta, UIN Sunan Kalijaga Yogyakarta, and UIN Maulana Malik Ibrahim Malang. The policy of MIT learning aims to enable the learning process at graduate schools to produce new comprehensive discoveries on science and humanities. Based on a qualitative research method, this showed that the graduate schools had different MIT approach and strategy in learning and this was greatly influenced by lecturer’s and decision maker’s paradigms. MIT approach was chosen respond to the nature of science, realize very complex issues, synergize various disciplines of sciences, motivate multi-sector expert collaboration, and produce new products. In short, MIT practices mean collaboration and synergy among involving people either experts with non-experts or academic with non-academic staff.
Parking pricing vs. congestion pricing: a macroscopic analysis of their impact on traffic

This paper focuses on parking pricing and congestion pricing and their short-term effects not only on traffic congestion but also on the potential revenue for a city. We develop a multimodal macroscopic traffic and parking search model based on aggregated data at the network level. Our methodology allows us to analyze how introducing parking pricing inside a network, or a congestion toll combined with a park and ride (P+R) scheme can affect the drivers’ decision between entering the network by car or using P+R. This decision directly influences the number of drivers using P+R, and this impacts, in turn, the traffic performance. We illustrate our proposed framework in a case study of an area with a high parking demand for public parking spaces within the city of Zurich, Switzerland. Results show that parking pricing combined with P+R is indeed a viable option compared to congestion pricing for improving traffic performance.
Assessing the Effectiveness of Differentiated Instructional Approaches for Teaching Math to Preschoolers with Different Levels of Executive Functions

Previous studies have found that the development of mathematical abilities, along with the development of executive functions, predict students’ subsequent academic performance. The present study aimed to assess the effectiveness of teaching the concept of area to preschool children with different levels of cognitive processes (CP) including executive functions and short-term memory. The experiment introduced the concept by using three different instructional approaches: traditional, contextual, and modeling. The sample included 100 children aged 6–7 years (M = 6.5 years), of whom 43% were boys. Each experimental condition included children with low, middle, and high levels of CP, as determined based on the NEPSY-II subtests. The children with low CP levels showed higher results in assimilating the notion of area after being taught using the contextual approach. In contrast, children with high CP levels showed a higher mastery of the concept of area following the use of the modeling approach. The results suggest the importance of CP development in building ways of mastering mathematical content. This contributes to choosing the optimal path of teaching mathematics for preschoolers, taking into account the development of their cognitive processes to improve their academic performance.
Empirical Exploration of Customer Management Focus and Its Impact on Business Performance

The aim of the study is to investigate the impact of different focus in customer management strategy on business performance. Strategies investigated in the paper are IT-focused strategy, data warehouse-focused strategy, and integra-tion-focused strategy. The effect of the strategies is examined in relation to both short-term and long-term performance. Combination of questionnaire and individual interviews was used to explore the particular dimensions of strategy focus. The sample for empirical research consisted of 195 companies from seven industry sectors in Slovakia. The findings show that different focus in strategy may bring different effects in performance outcomes. We also find that combining certain management styles may generate performance advantage
Authentically engaging youth with foster care experience: definitions and recommended strategies from youth and staff

ABSTRACT Child welfare service providers in the United States are increasingly acknowledging the importance of engaging youth with foster care experience in case planning, policy advocacy, and practice change. However, evidence for how to do this well is still quite limited. This study aims to answer two research questions: a) How do youth and staff/professionals define/conceptualize authentic youth engagement (AYE)? and b) What are youths’ and staff/professionals’ recommended strategies for authentically engaging youth? Thirty stakeholder interviews (15 youth, 15 staff/professionals) and 81 surveys (46 youth, 35 staff/professionals) were completed. Four themes emerged regarding conceptualizations of authentic youth engagement, while three themes emerged regarding recommendations for authentically engaging youth. These perspectives offer valuable insight into overcoming barriers related to authentically engaging youth in service provision, policy, and practice.
A SVM-3D Based Encoderless Control of a Fault-Tolerant PMSM Drive

This paper exhibits a novel technique to obtain an encoderless speed control of a permanent magnet synchronous motor (PMSM) in the case of a loss of one phase. The importance of this work is that it presents solutions in order to maintain the operation of the system in various conditions. This will increase the reliability of the whole drive system to meet the safety issues required in some applications. To achieve that, a fault-tolerant inverter modulated through a 3-dimension space vector pulse width modulation technique (3D-SVPWM) is used. Besides that, an algorithm to obtain the exact position of the saturation saliency in the case of a loss of one phase is introduced to achieve a closed-loop field-oriented encoderless speed control and to further enhance the reliability of the whole drive system. This algorithm is based on measuring the transient stator current responses of the motor due to the insulated-gate bipolar transistors (IGBTs) switching actions. Then according to the operating condition (normal or a loss of one phase), the saliency position signals are constructed from the dynamic current responses. Simulation results are provided to demonstrate the effectiveness of the saliency tracking technique under normal and under a loss of one phase conditions. Moreover, the results verify the maximum reliability for the whole drive system that is achieved in this work through a continuous operation of the drive system under a loss of one phase condition and under encoderless speed control.
Exploring Rice Genetic Resources to Improve Nutrient Use Efficiency

Rice, as a major staple crop, is one of the most important targets for plant breeders in an attempt to secure enough food for a growing world population. Producing nutrient efficient crops has become essential not only to attempt securing enough food for the growing population, but also to eliminate environmental consequences of using fertilizers. Nitrogen (N), phosphorus (P) and potassium (K) are major macronutrients that are rate limiting for plant growth and crop productivity. The aims of this project were to explore the genetic diversity of rice to identify genotypes with high efficiency under N, P and K deficient conditions, to identify chromosomal loci linked to NPK use efficiency using Genome Wide Association Studies (GWAS), and to manipulate a proton pump using CRISPR/Cas9 system with the aim of improving mycorrhiza-dependent nutrient uptake. Biomass and elemental analyses revealed considerable variations among 294 rice genotypes, and a subset of genotypes was identified that were relatively tolerant to NPK nutrient limitation. GWAS study revealed novel and previously known QTLs and genes with potential importance to the use efficiency of N, P and K. Alongside with N and K transporters and regulatory proteins, unexpectedly several genes involved in Na transport were identified as candidates. The CRISPR/Cas9 system was successfully applied to manipulate several candidate genes identified from GWAS, in addition to the rice H+-ATPase (OsHA1). Overall, the findings from this study can be used as a basis to conduct similar studies in other crops, which can all contribute to improve crop production, sustainable agriculture and food security.
Identification and characterization of Hydrogenophilus hirschii strain KB-DZ44 isolated from Hammam Righa hot spring in Algeria

The search for thermo- and extremophilic microorganisms as talented sources for highly stable enzymes has gained growing attention in recent research. The literature indicates that several microorganisms that have the ability to live under extreme conditions, such as thermophilic hot springs, volcanic and geothermal regions, are endowed with unique features of considerable interest to various industrial applications and processes. In this context, a thermophilic bacteria Hydrogenophilus hirschii strain KB-DZ44 was isolated from Hammam Righa hot spring in Ain Defla (Algeria). Identification of the isolate was done according to morphological, physiological, and biochemical characteristics and 16S rDNA sequence similarity as well. The temperature range for growth was 40–80 °C (opt. temp. 60 °C), pH range was 6–12 (opt. pH 6.5–7.5), and NaCl range of 0 to 4 g/L (opt.1- 1.5 g/L). 16S rDNA sequence and blast analyses confirmed that the isolate belonging to the genus Hydrogenophilus. The sequence was submitted to GenBank with accession number (KY646164).