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The self-resonating waterjet (SRWJ) has been applied in petroleum, natural gas, and mining engineering ever since its strong erosion ability in deep-hole drilling was recognized. Aiming at further improving the working efficiency of SRWJs, the effects of the exit angle of the organ-pipe nozzle on the axial pressure oscillations of the jet were experimentally studied. Six exit angles of θ = 0°, 30°, 45°, 60°, 75°, and 90° were employed in the experiment, and the axial pressure oscillation peak (Pmax) and amplitude (Pa) were used for characterizing the performance of SRWJs. It was found that the exit angle greatly affects the axial pressure oscillations, including the development trends against the standoff distance and the magnitudes of Pmax and Pa. Under testing with two inlet pressures, the exit angle of θ = 0° always resulted in the greatest Pmax and Pa within the range of the testing standoff distance. With the increase of standoff distance, both Pmax and Pa first increased and then decreased when the exit angle was 0°; while they kept decreasing when the exit angle was 30°, 45°, 60°, 75°, and 90°. Moreover, the exit angles of θ = 90° and 60°, corresponding to inlet pressures of Pi = 10 MPa and 20 MPa, led to both the minimum magnitudes of Pmax and Pa under the experimental conditions. The results also indicate that the exit angle affects the interactions between the nozzle lip and the jet and help provide information for improving the working efficiency of SRWJs in practical applications.

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Scientific retraction practices are intended to help purge the continued use of flawed research and assist in maintaining the integrity, credibility and quality of scientific literature. However, the practical effect of retraction is still vague and needs to be further explored. In this study, we analysed the citation counts and sentiments (positive/negative) of retracted articles in psychology journals from Web of Science to explore the effect of retraction. Causal inference strategies were used to measure the net effect of retractions on citation. Results show that the retraction practices induced the citation counts to reduce as expected. However, the proportion of negative citations also decreased because of retraction, indicating an unsatisfied effect. The retraction practice of high-impact factors and open access journals was more effective than other journals. The study integrated an understanding of the dissemination of erroneous publications and provided implications for liabilities involved in the whole retraction process.

PurposeThis study aims to compare the impacts of proceedings papers in the fields of social science and humanities (SSH) and science.Design/methodology/approachThis study involved not only citations but also altmetric indexes to compare the impacts of proceedings papers among multiple disciplines with 1,779,166 records from Conference Proceedings Citation Index (CPCI) in the Web of Science (WoS) in the period of 2013–2017. The mean value, concentration ratio, Lorenz curves and correlation analysis are utilized into the comparative analysis.Findings(1) Proceedings papers in science fields had higher scholarly impacts than those in SSH fields. (2) As for societal impact, clinical, pre-clinical and health still ranked first, whereas physical science and engineering and technologies were transcended by SSH fields, which is different from the scholarly impact of proceedings papers. (3) As for proceedings papers, citations and altmetric indexes have weak or moderate correlations in all six fields, indicating that altmetrics can be supplemented when assessing proceedings papers.Originality/valueThis study is expected to enhance the understanding of proceedings papers and to promote accuracy of evaluation for them by exhibiting the multidisciplinary differences of their scholarly and societal impacts.