Maintaining component dimensions in metal injection molding (MIM) is difficult because of significant component shrinkage in the sintering step and shrinkage variation. Most of the shrinkage variation in MIM is due to density inhomogeneity in moldings (greens), induced in the injection molding step. Therefore, the focus of this research was to clarify the relationship between injection molding parameters and shrinkage of a ring-shaped component molded into a four-cavity split mold. Material used in research was Catamold 310N in the form of ready to mold granules. An experiment, according to a 2k factorial design, was performed to evaluate the effects of holding pressure profiling on shrinkage at different levels of coolant temperatures and fill rates. Results showed that the interaction of holding profile and coolant temperature has the most influence on the mean shrinkage. This finding offers a possibility to maintain the component dimensions in MIM by using the revealed interconnection between holding pressure profile and mean shrinkage.
Multi-purpose reservoir Modrac is the most important water resource in Tuzla canton. Ecologically acceptable flow on dam Modrac is not adjusted with the latest Rulebook about methods of determining ecologically acceptable flow. This article shows the methods used to determine ecologically acceptable flow on the Modrac dam, respecting the fact that reservoir Modrac is declared as protected water resource. The given calculation of ecologically acceptable flow is made for II level of evaluation.
Aims: Assessing the effects of whole blood viscosity (WBV) on prognosis and deterioration in cardiac parameters in COVID-19 patients after recovery using cardiac magnetic resonance imaging (CMRI) and echocardiography is the purpose of this study. Methods: The study involved 70 patients. Patients who had COVID-19 pneumonia were admitted to the hospital. All patients met the eligibility criteria if they remained symptom-free of respiratory and cardiac symptoms and had negative swab test results at the end of the isolation period, for at least two weeks following the positive swab test result. Transthoracic echocardiography was performed within 24 hours prior to CMRI. WBV was measured in centipoises (cP) at 208 seconds-1 shear rate. The median value of WBV was calculated for the entire study population, which was subsequently utilized to divide the population into two subgroups. These were designated as high WBV and low WBV subgroups. Results: Elevated levels of hemoglobin, hematocrit, total protein, C-reactive protein, D-dimer, and fibrinogen were observed in individuals with high WBV. Conversely, TAPSE, S, and FAC were notably reduced in those with high WBV. Notably, CMRI revealed significant increases in native T1, native T2 mapping signal, and extracellular volume among patients with high WBV. Furthermore, in individuals with high WBV, there was a significant decrease in right ventricle stroke volume and right ventricle ejection fraction, accompanied by a notable increase in right ventricle end-systolic volume. Conclusion: WBV values measured during hospital admission may have early and late prognostic importance for COVID-19 infection.
Antibiotics constitute a group of medications used to treat infections caused by bacteria and their colonization. A casual understanding of the importance of rational antibiotic use results in antimicrobial resistance, leading to the ineffectiveness of the drug when it is most needed. Today, a pressing issue is bacterial resistance to antibiotics, one of the reasons being poor antibiotic management and insufficient knowledge about them. The purpose and objective of this research were to assess the knowledge and use of antibiotics among students of the Faculty of Health Sciences at the University of Sarajevo. This study involved 151 students, including 125 females (83%) and 26 males (17%). The survey comprised questions about general data on the significance and use of antibiotics. The importance of understanding antibiotics and knowing how to use them for specific problems is discussed in Chapter 3. of this scientific research paper.
Fused deposition modelling (FDM) is one of the mostly used additive technologies, due to its ability to produce complex parts with good mechanical properties. The selection of FDM process parameters is crucial to achieve good mechanical properties of the manufactured parts. Therefore, in this paper, a hybrid multi-criteria decision-making (MCDM) approach based on Preference Selection Index (PSI) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is proposed for the selection of optimal process parameters in FDM printing of polylactic acid (PLA) parts. Printing temperature, layer thickness and raster angle were considered as input process parameters. In order to prove the effectiveness of the proposed hybrid PSI – TOPSIS method, the obtained results were compared with the results obtained with different MCDM methods. The obtained best option of process parameters was confirmed by other MCDM methods. The optimal combination of process parameters to achieve the maximal flexural strength, maximal flexural modulus and maximal compressive strength is selected using the hybrid PSI-TOPSIS method. The results show that the hybrid PSI-TOPSIS approach could be used for optimisation process parameters for any machining process.
Each year, millions of birds migrate nocturnally over the North Sea basin, an area designated for significant offshore wind energy development. Wind turbines can harm aerial wildlife through collisions and barrier effects, especially when birds fly at low altitudes below the wind turbine rotor tip. We aim to quantify seasonal and nightly differences in flight altitudes of nocturnal bird migration over the North Sea and identify how weather influences low‐altitude flight to inform wind turbine curtailment procedures for reducing bird fatalities. We used bird tracking radars at Borssele and Luchterduinen offshore wind parks, 22 and 23 km from the western Dutch coast, to monitor altitude distributions during migration. We show that median flight altitude was higher in spring compared to autumn at Borssele (spring: 285.5 m, autumn: 169.2 m; p < .001, effect size [ES] = 0.0001) and Luchterduinen (spring: 133.8 m, autumn: 126.0 m; p < .001, ES = 0.002) and below wind turbine rotor tip in both seasons. On most nights in both seasons, the majority of migrants flew predominantly at low altitudes, except for intense migration nights in spring in Borssele where, on 87% of these nights, migration mainly occurred at high altitudes. The most important predictors of low‐altitude migration in both seasons were day of year and wind assistance. Birds chose altitudes with the most favorable wind conditions for migration in both seasons. The relationship between day of year and low‐altitude migration fraction suggests that different species migrate at different altitudes. In spring, birds were flying lower at the beginning and the end of the night, reflecting departures and arrivals of birds, while radar location in autumn was a good predictor of low‐altitude flights, indicating that different local migratory axes have distinct altitude distributions. Our findings suggest that mitigation measures offshore may be more effective during autumn than spring, especially on nights with more supportive wind conditions at altitudes below 300 m.
Introduction Multi-shell diffusion Magnetic Resonance Imaging (dMRI) data has been widely used to characterise white matter microstructure in several neurodegenerative diseases. The lack of standardised dMRI protocols often implies the acquisition of redundant measurements, resulting in prolonged acquisition times. In this study, we investigate the impact of the number of gradient directions on Diffusion Tensor Imaging (DTI) and on Neurite Orientation Dispersion and Density Imaging (NODDI) metrics. Methods Data from 124 healthy controls collected in three different longitudinal studies were included. Using an in-house algorithm, we reduced the number of gradient directions in each data shell. We estimated DTI and NODDI measures on six white matter bundles clinically relevant for neurodegenerative diseases. Results Fractional Anisotropy (FA) measures on bundles where data were sampled at the 30% rate, showed a median L1 distance of up to 3.92% and a 95% CI of (1.74, 8.97)% when compared to those obtained at reference sampling. Mean Diffusivity (MD) reached up to 4.31% and a 95% CI of (1.60, 16.98)% on the same premises. At a sampling rate of 50%, we obtained a median of 3.90% and a 95% CI of (1.99, 16.65)% in FA, and 5.49% with a 95% CI of (2.14, 21.68)% in MD. The Intra-Cellular volume fraction (ICvf) median L1 distance was up to 2.83% with a 95% CI of (1.98, 4.82)% at a 30% sampling rate and 3.95% with a 95% CI of (2.39, 7.81)% at a 50% sampling rate. The volume difference of the reconstructed white matter at reference and 50% sampling reached a maximum of (2.09 ± 0.81)%. Discussion In conclusion, DTI and NODDI measures reported at reference sampling were comparable to those obtained when the number of dMRI volumes was reduced by up to 30%. Close to reference DTI and NODDI metrics were estimated with a significant reduction in acquisition time using three shells, respectively with: 4 directions at a b value of 700 s/mm2, 14 at 1000 s/mm2, and 32 at 2000 s/mm2. The study revealed aspects that can be important for large-scale clinical studies on bundle-specific diffusion MRI.
Objectives: The purpose of the present study was to assess neck-to-height ratio (NtHR) and its possible association with other anthropometric measures of obesity and blood pressure (BP) values in Bosnian university students stratified by new 2017 American College of Cardiology/American Heart Association Task Force hypertension (HT) guidelines.Methods: The present study included 417 subjects with median age 20 (19-21) years that were divided into normal BP, elevated BP, stage 1 HT, and stage 2 HT groups based on BP measurements using auscultatory methods. Standard anthropometric indices including neck circumference (NC) were measured. NtHR (cm/m) was calculated in each participant based on the NC and height. Differences between groups were assessed by Kruskal-Wallis followed by Man-Whitney test and correlations were determined by Spearman test.Results: The prevalence of elevated BP was 19.2%, stage 1 HT 21.6%, and stage 2 HT 11.0 %. NtHR was highest in the stage 2 HT group. NtHR correlated significantly with all anthropometric measures in all groups. No correlation between NtHR, systolic BP, and diastolic BP was found, except in the stage 1 HT group, where a significant correlation between NtHR and systolic BP was uncovered.Conclusions: Based on the observed correlations between NtHR and standard measures of obesity, NtHR could be included in clinical practice, since it is simple and does not induce discomfort. The high prevalence of elevated BP found in the present study suggests HT prevention requires the implementation of programs aimed at promoting healthy dietary habits, physical activity, as well as effective stress management and coping mechanisms.
The Teaching and Learning International Survey (TALIS) collects data from representative samples of teachers and principals across the world about their practices and work conditions, school and classroom contexts, and attitudes, motivation, and satisfaction with their profession and jobs. Given the growth of participating countries, the number of constructs assessed, and the volume of publications based on secondary analyses of the freely available data, it is reasonable to claim that TALIS represents one of the major data sources in the field of international educational research. This study provides a systematic literature review of secondary analyses of TALIS data, summarising the past 15 years of TALIS research. The review includes a synthesis of 238 peer‐reviewed journal articles, providing bibliographical information about articles as well as the scope and impact of analysis of TALIS data across time, countries, and populations. Moreover, the article summarises information about the most prevalent research themes that have been investigated. The findings highlight the importance of TALIS data in the broader educational research scope, emphasising themes such as teacher characteristics, and teacher professional practices. Lastly, the review provides insights into methodological approaches to study and analyse TALIS data and calls for more caution in analysing complex survey data with respect to how clustering and multigroup design are handled.
With the development and implementation of the 5G systems worldwide, the shortages and imperfections that limit the functions and services of 5G networks were made apparent. This generation should enable its users to access unseen services and applications and a better quality of service in comparison to its predecessors. However, aside from the apparent importance of 6G networks, the possibilities, use cases, applications, and services that this technology would provide are yet to be explored. Our intention with this paper is to research the papers and compare the differences in requirements, capabilities, services, and use cases between 5G and 6G.
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