A novel numerical modeling of microsecond laser beam percussion micro-drilling of Hastelloy X:experimental validation and multi-objective optimization

The paper investigates the characteristics of the laser beam percussion micro-drilling (LBPMD) process in aerospace nickel-based superalloy Hastelloy X using microsecond pulses. The quality of the drilled hole is crucial in laser beam micromachining, and selecting appropriate process parameters significantly impacts the hole’s quality. The objective is to achieve predefined hole dimensions with minimal taper angles. Additionally, the study focuses on the alteration of pulse width, which is a combination of laser pulse frequency and duty cycle. Laser power (P), duty cycle % (D), focal plane position (FPP), and laser frequency (f) are considered input parameters, while geometric features such as inlet and outlet diameters, hole taper angle, and inlet circularity are examined as process responses. ANOVA is employed to establish significant relationships between process parameters and response variations based on experimental tests. Creating a precise simulation model that accurately accounts for the moving boundary of the target material’s receding surface is a crucial and challenging task in formulating the laser heat conduction problem. It is necessary to simultaneously capture the material’s dynamic front movement and update the boundary conditions of the laser source. To model the micro-drilled hole with LBPMD, the UMESHMOTION and DFLUX subroutines, along with the arbitrary Lagrangian-Eulerian (ALE) adaptive remesh algorithm in the Abaqus™ software, are utilized. Notably, no previous numerical study has predicted the geometry of micro-drilled holes using this technique. The proposed procedure is validated through the predictions of inlet and outlet hole diameters. Special emphasis is placed on the validation of models. Consequently, the numerical model and statistical model are compared as well as the need to define model applicability. The study demonstrates that all input parameters significantly influence the inlet hole diameter, while the pulse width notably affects the taper angle and circularity. The interaction between high laser frequency and low duty cycle results in reduced pulse duration. Multi-objective optimization is performed to determine the optimal process parameter settings for desired quality characteristics, considering minimum hole taper angle, precise inlet diameter, and maximum inlet circularity of the hole as optimization criteria. The findings show that with the optimized predicted results obtained from the optimal input variables, a composite desirability of 92% can be achieved

Crustal thickness and Moho character of the fast-spreading East Pacific Rise from 9°42′N to 9°57′N from poststack-migrated 3-D MCS data

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 15 (2014): 634–657, doi:10.1002/2013GC005069.We computed crustal thickness (5740 ± 270 m) and mapped Moho reflection character using 3-D seismic data covering 658 km2 of the fast-spreading East Pacific Rise (EPR) from 9°42′N to 9°57′N. Moho reflections are imaged within ∼87% of the study area. Average crustal thickness varies little between large sections of the study area suggesting regionally uniform crustal production in the last ∼180 Ka. However, individual crustal thickness measurements differ by as much as 1.75 km indicating that the mantle melt delivery has not been uniform. Third-order, but not fourth-order ridge discontinuities are associated with changes in the Moho reflection character and/or near-axis crustal thickness. This suggests that the third-order segmentation is governed by melt distribution processes within the uppermost mantle while the fourth-order ridge segmentation arises from midcrustal to upper-crustal processes. In this light, we assign fourth-order ridge discontinuity status to the debated ridge segment boundary at ∼9°45′N and third-order status at ∼9°51.5′N to the ridge segment boundary previously interpreted as a fourth-order discontinuity. Our seismic results also suggest that the mechanism of lower-crustal accretion varies along the investigated section of the EPR but that the volume of melt delivered to the crust is mostly uniform. More efficient mantle melt extraction is inferred within the southern half of our survey area with greater proportion of the lower crust accreted from the axial magma lens than that for the northern half. This south-to-north variation in the crustal accretion style may be caused by interaction between the melt sources for the ridge and the Lamont seamounts.This research was supported by the National Science Foundation grants OCE0327872 to J. C. M., S. M. C., OCE327885 to J. P. C., OCE0624401 to M. R. N., and NSERC Discovery, CRC and CFI grants to M. R. N.2014-09-1

Constraints on melt content of off-axis magma lenses at the East Pacific Rise from analysis of 3-D seismic amplitude variation with angle of incidence

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 122 (2017): 4123–4142, doi:10.1002/2016JB013785.We use 3-D multichannel seismic data to form partial angle P wave stacks and apply amplitude variation with angle (AVA) crossplotting to assess melt content and melt distribution within two large midcrustal off-axis magma lenses (OAMLs) found along the East Pacific Rise from 9°37.5′N to 9°57′N. The signal envelope of the partial angle stacks suggests that both OAMLs are partially molten with higher average melt content and more uniform melt distribution in the southern OAML than in the northern OAML. For AVA crossplotting, the OAMLs are subdivided into seven ~1 km2 analysis windows. The AVA crossplotting results indicate that the OAMLs contain a smaller amount of melt than the axial magma lens (AML). For both OAMLs, a higher melt fraction is detected within analysis windows located close to the ridge axis than within the most distant windows. The highest average melt concentration is interpreted for the central sections of the OAMLs. The overall low OAML melt content could be indicative of melt lost due to recent off-axis eruptions, drainage to the AML, or limited mantle melt supply. Based on the results of this and earlier bathymetric, morphological, geochemical, and geophysical investigations, we propose that the melt-poor OAML state is largely the result of limited melt supply from the underlying mantle source reservoir with smaller contribution attributed to melt leakage to the AML. We hypothesize that the investigated OAMLs have a longer period of melt replenishment, lower eruption recurrence rates, and lower eruption volumes than the AML, though some could be single intrusion events.National Science Foundation; CFI; CRC2017-12-2

Architecture of on- and off-axis magma bodies at EPR 9°37–40′N and implications for oceanic crustal accretion

Crustal accretion at fast-spreading mid-ocean ridges is believed to be concentrated in a narrow zone up to a few kilometers wide centered beneath the ridge axis. However, there is increasing evidence for off-axis magmatism occurring beyond this narrow zone. Here, we present 3D multichannel seismic (MCS) images from the East Pacific Rise 9°37–40′N extending to 11 km on the ridge flanks. In the axial region, two offset axial magma bodies underlie a small ridge-axis discontinuity at ∼9°37′N, displaying an overlapping geometry similar to that of the seafloor structures above. On the ridge flanks, a series of off-axis magma lenses (OAML) are imaged: they are located 2–10 km from the ridge axis, at 700 to 1520 ms two-way travel time below seafloor (bsf) (∼1.6 to 4.5 km bsf), with variable areas ranging from 0.5 km2 to 5.2 km2. The largest body is centered 4 km east of the ridge axis and is composed of a large, continuous, flat-topped lens and a series of small, discontinuous, westward-dipping bodies along its western edge. The flat crest of the OAML lies at approximately the same depth beneath layer 2A as the axial magma lens and we infer that this OAML has formed by aggregation of ascending melts that accumulate at the base of the sheeted dike section. A cluster of reflections underlying the OAML at 1260–1510 ms bsf are observed that may be deeper lenses feeding melts to the upper lens. This largest OAML is associated with Moho travel time anomalies of 120–260 ms within a zone that extends up to 2 km from the edge of the OAML, suggesting a lower crust that is partially molten with lower crustal velocities reduced by 8–18% and/or thicker than normal by up to 1 km. Local volcanic edifices are found above two of the three OAMLs imaged in our study area and are inferred to be the eruptive products of the OAMLs. From the volume of these edifices and the Moho travel time anomalies we estimate the potential contribution of off-axis magmatism to the total volume of the crust to be ∼0.01–3%. The OAMLs imaged in our study area are present over roughly the same distance range as the zone of formation of near-axis seamounts. We speculate that OAMLs and the volcanic edifices found above them are small-scale manifestations of the off-axis magmatism that gives rise to near-axis seamounts

Effects of human and organizational deficiencies on workers’ safety behavior at a mining site in Iran

OBJECTIVES Throughout the world, mines are dangerous workplaces with high accident rates. According to the Statistical Center of Iran, the number of occupational accidents in Iranian mines has increased in recent years. This study investigated and analyzed the human and organizational deficiencies that influenced Iranian mining accidents. METHODS In this study, the data associated with 305 mining accidents were analyzed using a systems analysis approach to identify critical deficiencies in organizational influences, unsafe supervision, preconditions for unsafe acts, and workers’ unsafe acts. Partial least square structural equation modeling (PLS-SEM) was utilized to model the interactions among these deficiencies. RESULTS Organizational deficiencies had a direct positive effect on workers’ violations (path coefficient, 0.16) and workers’ errors (path coefficient, 0.23). The effect of unsafe supervision on workers’ violations and workers’ errors was also significant, with path coefficients of 0.14 and 0.20, respectively. Likewise, preconditions for unsafe acts had a significant effect on both workers’ violations (path coefficient, 0.16) and workers’ errors (path coefficient, 0.21). Moreover, organizational deficiencies had an indirect positive effect on workers’ unsafe acts, mediated by unsafe supervision and preconditions for unsafe acts. Among the variables examined in the current study, organizational influences had the strongest impact on workers’ unsafe acts. CONCLUSIONS Organizational deficiencies were found to be the main cause of accidents in the mining sector, as they affected all other aspects of system safety. In order to prevent occupational accidents, organizational deficiencies should be modified first

Investigating the Relationship between Optimal Use of Knowledge and Intellectual Capital Management among Library Managers of Public Hospitals

Today, the impact of intellectual capital is interesting for the scholars worldwide regarding the performance of the organizations, and knowledge comprises its primary core. Optimal use of knowledge contributes to explore needs of clients, leading to innovation and new valuable opportunities. Qualitatively improved services in the libraries of hospitals realizes through taking human capital and their optimal use of knowledge into consideration. The present study investigated the relationship between optimal use of knowledge and intellectual capital among library managers of public hospitals in Tehran. This study is a descriptive-correlation applied research holding all of the library managers of public hospitals in Tehran as the statistical population. The data collection was carried out via Bontis Intellectual Capital Questionnaire (2004) and Bukowitz & Williams Knowledge Management Questionnaire (1999). Cronbach's alpha was employed to measure the internal consistency reliability among the items and found at over 70%. To analyze the statistical data, the Pearson Correlation Test was used. The results showed that there were not any significant relationship between optimal use of knowledge and human resource capital and structural capital components (P>0.05). On the whole, between intellectual capital and optimal use of knowledge there is a significant relationship (P<0.05).The data analysis revealed that there is a positive and direct significant relationship with low intensity between optimal use of knowledge and intellectual capital among library managers of public hospitals in Tehran. In other words, the Foucault theory of power relation is confirme

STRAW-b (STRings for Absorption length in Water-b): the second pathfinder mission for the Pacific Ocean Neutrino Experiment

Since 2018, the potential for a high-energy neutrino telescope, named the Pacific Ocean Neutrino Experiment (P-ONE), has been thoroughly examined by two pathfinder missions, STRAW and STRAW-b, short for short for Strings for Absorption Length in Water. The P-ONE project seeks to install a neutrino detector with a one cubic kilometer volume in the Cascadia Basin's deep marine surroundings, situated near the western shores of Vancouver Island, Canada. To assess the environmental conditions and feasibility of constructing a neutrino detector of that scale, the pathfinder missions, STRAW and STRAW-b, have been deployed at a depth of 2.7 km within the designated site for P-ONE and were connected to the NEPTUNE observatory, operated by Ocean Networks Canada (ONC). While STRAW focused on analyzing the optical properties of water in the Cascadia Basin, \ac{strawb} employed cameras and spectrometers to investigate the characteristics of bioluminescence in the deep-sea environment. This report introduces the STRAW-b concept, covering its scientific objectives and the instrumentation used. Furthermore, it discusses the design considerations implemented to guarantee a secure and dependable deployment process of STRAW-b. Additionally, it showcases the data collected by battery-powered loggers, which monitored the mechanical stress on the equipment throughout the deployment. The report also offers an overview of STRAW-b's operation, with a specific emphasis on the notable advancements achieved in the data acquisition (DAQ) system and its successful integration with the server infrastructure of ONC.Comment: 20 pages, 11 figures, 2 table

Ranking Technological Capability in the Countries of the Organization for Economic Cooperation and Development with MCDM Approach

In this paper, we ranking member countries of the Organization for Economic Cooperation and Development using various indices derived from various models of technological capabilities at the national level, and Development multiple criteria decision making using technological capability. In the first method, a Library, a review of relevant literature is done. The most important criteria to evaluate the model and technological capabilities at the national level have been studied and eventually selected 14 indicators as decision criteria. Then using a simple weighted sum of decision-making techniques, TOPSIS and electree, OECD countries in terms of technological capabilities have been rated. Then, to merge the results of each technique, Copeland method is used. This research is quantitative aspects of the method in terms of investigations of applied research. Based on the research findings, America, Japan and Germany as the leading technological capabilities and economic cooperation among the member states as they develop

Unveiling the potential of renewable energy and battery utilization in real-world public lighting systems: A review

Lighting systems, as one of the biggest energy consumers on a global scale, are being upgraded based on innovative energy-saving (hereafter E-saving), energy-efficiency (E-efficiency), and energy-cost (E-cost) reduction schemes. According to research, among lighting systems, public lighting systems (PLSs) have significant potential for such energy projects. It can be realized through smart dimming, installing light-emitting diode (LED) luminaries, using renewable energy, etc. Accordingly, this work reviews the E-saving, E-efficiency, and E-cost reduction schemes for real-world PLSs by giving related techno-economic formulation. In this regard, smart control/dimming approaches via combined Internet of Things and wireless technologies, installing LED luminaires, optimal layout design, reactive power compensation, etc., are discussed by reporting the saving potentials, the payback period of the investment, and carbon reduction effects. Moreover, the use of renewable energy (including photovoltaic panels, wind turbines, pump-as-turbine systems, biomass plants, etc.) integrated with batteries to power PLSs is discussed by giving the E-cost reduction potential. Moreover, the pros/cons of previous works, the key findings of this review work, and recommendations for future works are outlined. This work shows future research directions, identifies high-potential energy projects for energy planners, and outlines the importance of renewable energy in making PLSs more environmentally friendly. Moreover, the role of energy policymakers’ financial support in expediting the widespread enforcement of energy projects is outlined by studying the payback period of projects, which is about 5–7 years (on average 5.8 years, 6.9 years, 4.9 years, and 5.6 years for E-saving, E-efficiency, combined E-saving/E-efficiency, and E-cost reduction schemes, respectively).<br/

Job Motivating Potential Score and Its Relationship with Employees' Organizational Commitment among Health Professionals

AbstractObjectivesJob motivation affects the productivity and performance, job satisfaction, and organizational commitment of the employees of each organization. Alternatively, understanding factors affecting motivation provokes a sense of creativity and innovation in employees. The purpose of this study was to investigate the relationship between jobs' motivating potential scores and employees' organizational commitment.MethodsA cross-sectional study was conducted in an educational hospital of Yazd, Iran, in 2014 and 2015. A total of 181 employees from different units of the hospital contributed to this study. We used the stratified-random sampling method for choosing the required sample from different wards. Required data were gathered using two valid questionnaires. After completing the questionnaires, collected data were analyzed using statistical software SPSS version 19. We used descriptive statistics, analysis of variance, and Spearman correlation coefficients in data analyses.ResultsResults showed that the majority of study participants rated their jobs as low motivating and the mean motivating potential score and its three components (task identity, autonomy, and feedback) were below the mean standard. The motivating potential score and its three components, including job variety, feedback, and autonomy, have a significant positive correlation with organizational commitment. These results confirm that any improvement of job characteristics will lead to organizational commitment incensement.ConclusionOur study observed a negative correlation between some motivating potential dimensions and some kinds of organizational commitment, including the correlation of task identity, skill variety, and feedback with normative commitment and the relation of task significance with affective commitment. These are surprising results that need to be studied more