Direction Of Path Research Articles

Cardinal and Ordinal Directions Approach in Investigating Arrayed Solder Joints Crack Propagation of Ball Grid Array Semiconductor Packages

An accelerated reliability testing via thermal cycling test (TCT) was used to test ball grid array (BGA) components’ reliability. Five variables were observed; control sample J and samples K, L, M, and N were BGA component samples that have been exposed to TCT between 500 and 1250 cycles with the TCT profile in the range of 0 °C–100 °C. The crack orientation of the individual solder joint was analyzed along with the propagation path pattern on the solder array of the BGA component pad by analyzing the dye and pull test results that were then mapped and analyzed using the cardinal and ordinal directions approach. This is to determine the crack propagation path direction in the solder array and track the potential of warpage on the BGA package as the TCT cycles progressed. A cross section was performed on sample M with the 3-D X-ray and scanning electron microscopy (SEM) analysis to observe the solder joints’ fracture lines and surface topographies. The results showed that individual solder joint crack orientation is correlated to the crack propagation location on the BGA package. The solder joint from northwest (NW), northeast (NE), southeast (SE), and southwest (SW) of the BGA package is prone to solder crack compared to the solder joint array in the middle. A solder grain structure coarsening occurred at the crack propagation due to the high cyclic strain from the TCT.

An Optical Navigation System for Autonomous Aerospace Systems

An innovative electro-optical navigation system called Optical Navigation System (OptoNav) for Autonomous Landing consisting of a machine vision camera, and a set of co-registered structured light beacons is proposed. OptoNav is used to directly sense the altitude and two orientation states of an air vehicle with respect to the flight path direction. Motivated by autonomous landing applications involving fixed-wing aircraft, the machine vision camera is used to process the images of the runway so as to establish a moving coordinate system affixed to the runway, making use of the perspective geometry of the camera system. Three or more structured light emitters are used to make direct measurements of the range using the geometry of the perspective projection model by making use of the co-registration of the camera with respect to the structured light emitting sources. A unique formulation of the minimal relative motion states is used to directly estimate the three states of altitude, pitch and roll angle of the airframe with respect to the moving coordinates affixed to the runway. Laboratory experiments are used to validate the utility of the OptoNav sensor system.

The Effect of Job Esteem on Career Decision Level and Major Satisfaction of Hair and Beauty Major Students

The purpose of this study is to investigate the relationship between career decision level and major satisfaction among hair and beauty major students, and to present basic data and implications for hair and beauty majors' educational direction and career path. The job esteem of hair and beauty major students was found to be four sub-factors, career decision level was two factors, and satisfaction with major was three factors. Positive value, social benefit, and relative benefit of job esteem showed statistically significant results for major suitability, and social benefit, negative treatment, and relative benefit showed statistically significant results for subject satisfaction. The job esteem of hair and beauty major students is an important variable in career decision level and major satisfaction. Therefore, if students majoring in hair and beauty are satisfied with their majors and if student competency is strengthened, excellent human resources to lead the hair and beauty industry can be nurtured. Although this study was conducted with limited research subjects and variables, it is hoped that a comprehensive and practical study that considers various variables will continue in follow-up studies.

Natural Environment Protection Strategies and Green Management Style: Literature Review

The relationships between the Green Management Style (GMS) and Natural Environment Protection Strategies (NEPS) are rarely explored in scientific research. The nature of these relations is not fully explained in management sciences, and although these connections are important determinants for the choice between temporary and Sustainable Development (SD) in business organizations, they are accompanied by research gaps. The first research gap is recognized qualitatively in the literature review, which indicates the scarcity of theoretical research in the areas of NEPS and the GMS concerning Sustainable Development Goals (SGDs). The second quantitative research gap is dedicated to the rarity of empirical studies among business organizations engaged in NEPS and the GMS’s implementation. The third qualitative research gap lies in the difficulty of translating scientific assumptions from the theoretical background into business practice. This paper aims to present and explore the indicated research gaps and propose a theoretical model of the relationships between the GMS and NEPS. The adopted method used in this article is a Systematic Literature Review (SLR) supported by a bibliometric study performed in VOSviewer software. The results of the present study of relationships between the GMS and NEPS are explained by the Green Integrity Model (GIM). The green integrity between the researched elements can influence organizations’ decision-making processes related to development path directions, social and environmental responsibility, workers’ engagement, strategy communication, and organizational performance. In terms of the relationships between NEPS and the GMS, this can be seen as a part of the manner in which business organizations self-regulate.

Combustion characteristic of 2,3,3,3-tetrafluroropropene (R1234yf)

To describe the combustion process of hydrofluoroolefins (HFOs) 2,3,3,3-tetrafluroropropene (R1234yf), a kinetics mechanism was developed. On the M06–2X/6–311++G(d,p) level, dynamic calculations have been performed using the density function theory (DFT) method. Proposed R1234yf kinetic reactions included unimolecular decomposition and intermolecular reactions, such as collisions with O2, OH, and H radicals. The results indicated that R1234yf combustion is a step-by-step chain reaction involving chain initiation (unimolecular lysis and collision reaction with oxygen), chain transmission (collision reactions with free radicals), and chain termination. In conjunction with the priority rule of kinetics reactions, a schematic diagram of the primary microscopic combustion pathways for R1234yf was created at 298.15 K and 1 atm. All the simulation results could provide a data basis to establish the kinetic model of hydrofluoroolefin pyrolysis and combustion. In addition, to verify the product direction of the reaction path, experiments were conducted to determine the properties of the R1234yf combustion products.

Fatigue behaviour of re-entrant auxetic structures made of the aluminium alloy AA7075-T651

An investigation of the fatigue behaviour of the re-entrant auxetic structures made of the aluminium alloy AA 7075-T651 is presented in this study. The analysed auxetic structures represent a new class of cellular structures that show anomalous deformation responses such as negative Poisson’s ratio. In the proposed work, the influence of the unit cell orientation on the crack path and fatigue life was studied using experimental and computational approaches. The Low Cycle Fatigue (LCF) tests were performed at load control with the load ratio 0.1 in tension. In the LCF tests five loading levels were selected, and at least two tests were performed at each loading level. The same loading conditions were then applied in the computational model in the framework of the ANSYS software package, where a nonlinear kinematic material model was applied to obtain the stress–strain relationship. The strain-life approach, with consideration of the Morrow mean stress correction, was then used to obtain the fatigue life of the analysed auxetic structures. The experimental and computational results showed that the unit cell’s orientation has a minor influence on the fatigue life of both analysed auxetic structures, but impact on the direction of the fatigue failure path significantly.

Fearless Dominance and Leader Effectiveness: Lykken’s Socialization Hypothesis (WITHDRAWN)

We tested Lykken’s (1995) hypothesis that fearless dominance can lead to both adaptive and antisocial behaviors. According to Lykken, the direction of the career path of individuals high on fearless dominance is mainly influenced by their level of socialization, and prior research has found encouraging results for this hypothesis. However, research also shows that the presence of fearless dominance increases at higher levels of an organization’s hierarchy. Therefore, our goal was to test Lykken’s socialization hypothesis in a leadership context. By linking Lykken’s hypothesis to socioanalytic theory and a recent process model of leadership, we suggest that fearless dominance and successful socialization (i.e., higher educational level) influence leadership outcomes via political skill. Our sample comprises 239 leaders, their superiors (N = 239), and a total of 457 subordinates. Using moderated mediation analyses, we show that leaders high on both fearless dominance and educational level possessed greater political skill, mediating improved job performance, transformational leadership, and team performance. However, with low educational level, this mediated relation is negative. We discuss these results regarding Lykken’s hypothesis and provide an outlook for future research.

Spectrum Shaping for Multiple Link Discovery in 6G THz Systems

This paper presents a novel antenna configuration to measure directions of multiple signal sources at the receiver in a THz mobile network via a single channel measurement. Directional communication is an intrinsic attribute of THz wireless networks and the knowledge of direction should be harvested continuously to maintain link quality. Direction discovery can potentially impose an immense burden on the network that limits its communication capacity exceedingly. To utterly mitigate direction discovery overhead, we propose a novel technique called spectrum shaping capable of measuring direction, power, and relative distance of propagation paths via a single measurement. We demonstrate that the proposed technique is also able to measure the transmitter antenna orientation. We evaluate the performance of the proposed design in several scenarios and show that the introduced technique performs similar to a large array of antennas while attaining a much simpler hardware architecture. Results show that the spectrum shaping with only two antennas placed 0.5 mm, 5 mm, and 1 cm apart performs direction of arrival estimation similar to a much more complex uniform linear array equipped with 7, 60, and 120 antennas, respectively.

Strain Release Behaviour during Crack Growth of a Polymeric Beam under Elastic Loads for Self-Healing.

The response of polymeric beams made of Acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) in the form of 3D printed beams is investigated to test their elastic and plastic responses under different bending loads. Two types of 3D printed beams were designed to test their elastic and plastic responses under different bending loads. These responses were used to develop an origami capsule-based novel self-healing mechanism that can be triggered by crack propagation due to strain release in a structure. Origami capsules of TPU in the form of a cross with four small beams, either folded or elastically deformed, were embedded in a simple ABS beam. Crack propagation in the ABS beam released the strain, and the TPU capsule unfolded with the arms of the cross in the direction of the crack path, and this increased the crack resistance of the ABS beam. This increase in the crack resistance was validated in a delamination test of a double cantilever specimen under quasi-static load conditions. Repeated test results demonstrated the effect of self-healing on structural crack growth. The results show the potential of the proposed self-healing mechanism as a novel contribution to existing practices which are primarily based on external healing agents.

A Study on the Residual Stress of the Co-Based Alloy Plasma Cladding Layer.

The distribution law of residual stress in multi-channel scanned plasma cladding of Co-based alloy under different process parameters was studied by means of simulation and tests, and the optimum process parameters were optimized. The simulation model of the plasma cladding stress field was established by ABAQUS software, and the influence law of the working current, scanning speed, and scanning mode on the residual stress of the Co-based alloy multi-channel scanning was studied. A set of optimal cladding process parameters were obtained. The residual stress of the cladding layer was measured by the blind hole method and compared with the stress value in the finite element model. The results show that there is residual tensile stress on the surface of the cladding layer. The residual stress along the direction of the scanning path is greater than that along the direction of the scan sequence. The residual stress increases with the increase of the working current. The scanning speed is greater, and the residual stress is smaller. The residual stress of the short-edge scanning is greater than that of the long-edge scanning. The residual stress of the successive scanning is greater than that of the reciprocating scanning. The long-edge reciprocating scanning is the best scanning mode. The best combination of process parameters is the working current of 90 A, the scanning speed of 100 mm/min, and the long-edge reciprocating scanning mode.

Longitudinal graded porous titanium fabricated by spark plasma sintering: Design of layers, direction of crack path

The design of layers and fabrication methods strongly affect the stress bearing capacity and crack propagation in functionally graded porous titanium (FGPT). Thus, in this study, uniform and functionally graded porous titanium (in three and five-layer structures) samples were fabricated using spark plasma sintering at 440 °C and 50%vol. space holder (NaCl). Compression results proved that selecting the highest NaCl in the center of five-layered samples, besides the smoothest porosity gradient, increases energy absorption up to ≅360 % compared with the uniform foam. The architectural design, along with the energy absorption, affects the crack direction and fracture pattern remarkably. Obviously, two types of cracks path, i.e., vertical and oblique, were detected in uniform and different graded samples, which the latter direction highlighted the Griffith rupture mechanism. Meanwhile, although trumpet-like and crushed/disc fracture patterns perceived in layered structures, promptly fragmented patterns were dominated in the uniform porous sample. This work provides an appropriate method with a suitable layers arrangement to fabricate FGPTs with incredible energy absorption due to crack arresting/deflecting and homogenizing strut thickness.

Tornado Radar Images and Path Directions: An Assessment of Public Knowledge in the Southeastern United States

Abstract Due to the current use and reliance on tornado warning polygons, several published articles have concentrated on themes related to risk perception and interpretation of risk within and outside of polygons. Despite the general success of warning polygons, not everybody is able to spatially estimate their risk by looking at maps with tornado warning polygons. Using polygons in conjunction with radar images can improve comprehension and better inform protective action decision-making for tornado warnings. Additionally, a potential latent area of research is how past tornado tracks and climatological knowledge about tornado path directions may influence tornado risk perception and protective action decision-making. In this study, we surveyed 1,023 individuals across the southeastern United States. Participants were asked to rate their level of concern for a tornadic supercell moving toward two locations. They were also asked to name the direction tornadoes usually come from and travel toward in their counties. Results indicated significantly more concern about the radar reflectivity within the supercell than concern about the location of the hook echo. Additionally, the perceived directions of tornado paths across the region were inaccurate with 75% of the sample either not answering, indicating that they did not know the most common direction for tornado paths, or answering that tornadoes travel in uncommon or unrealistic path directions. The Atlanta metropolitan area was used as a case study to illustrate inaccurate perceptions of path directions.

Optimization design for dynamic characteristics of face gear drive with surface-active modification

The surface-active modification(SAM) method is proposed to decrease the vibration of the face gear drive. Firstly, the unloading performances such as the fourth-order transmission error(4-TE), the length of the contact ellipse, and the direction of the contact path are preset to modify the face gear pair. Secondly, a dynamic model is developed to attain the normal vibration acceleration(NVA) which is chosen as the optimization objective. The genetic algorithm(GA) is applied to solve the optimization model for searching for the optimal modification parameters. Thirdly, a numerical calculation is performed to investigate the influence of the modification parameters and the meshing stiffness on vibration. Besides, the bifurcation characteristics of the system are also explored. The results show that the amplitude of the loaded transmission error(ALTE) and the vibration are reduced after the optimization. Not only is vibration linked to mean meshing stiffness, but also the harmonic amplitude of meshing stiffness impacts it significantly. SAM lessens the range of chaotic motion, which helps to improve system stability. This study provides a theoretical basis for the vibration reduction of face gear pairs design.

Orientation behavior and thermal conductivity of liquid crystal polymer composites based on Three-Dimensional printing

Liquid Crystal Polymer (LCP) / hexagonal boron nitride (BN) composites are manufactured bythree-dimensional (3D)printing approach. The results confirm that 3D printing can build up LCP bulk material with highly aligned nematic domains along the printing path. Also, BN can be orderly arrangement in matrix, exhibiting the same oriented direction as LCP molecules. The degree of orientation of BN is relevant to its lateral dimension. BN with a lateral size of 50 um in LCP matrix has a much higher degree of orientation compared with BN with a lateral size of 0.5 um and 5um. The well-ordered arrangement of BN and aligned LCP result that all of the printed sample has high thermal conductivity. The printed neat LCP bulk has a thermal conductivity 0.74 W m−1 K−1 parallel to the printing path direction, being filled with 20% mass fraction of BN, it can reach to 1.77 W m−1 K−1.

Analysis of Sustainable Development of the Chinese Golf Industry from the Perspective of Environmental Social Responsibility

Purpose – The purpose of this paper is to sort out the construction of environmental social responsibility at home and abroad, analyze the logical relationship between the construction of environmental social responsibility and the sustainable development of the golf industry, and come to the conclusion that we should speed up the construction of environmental social responsibility of enterprises and form a green health industry chain with a full life cycle.
 Design/Methodology/Approach – Based the on the SWOT analysis method, based on the internal and external environment and conditions, draws a series of corresponding conclusions or strategies through investigation, research, arrangement and combination of various main inner strengths, weaknesses, external opportunities and threats closely related to the research object.
 Findings – This paper studies, Through SWOT analysis, the strategic measures for the sustainable development of Chinese golf from the perspective of environmental and social responsibility are obtained.
 Research Implications – In the management of this paper, This study makes China’s golf industry consider environmental and social benefits and realize the synergy and unity of economic, environmental, and social benefits.
 China’s golf industry’s sustainable development direction and innovation path have certain practical significance.

Clinical applications and prospects of 3D printing guide templates in orthopaedics.

BackgroundWith increasing requirements for medical effects, and huge differences among individuals, traditional surgical instruments are difficult to meet the patients' growing medical demands. 3D printing is increasingly mature, which connects to medical services critically as well. The patient specific surgical guide plate provides the condition for precision medicine in orthopaedics.MethodsIn this paper, a systematic review of the orthopedic guide template is presented, where the history of 3D-printing-guided technology, the process of guides, and basic clinical applications of orthopedic guide templates are described. Finally, the limitations of the template and possible future directions are discussed.ResultsThe technology of 3D printing surgical templates is increasingly mature, standard, and intelligent. With the help of guide templates, the surgeon can easily determine the direction and depth of the screw path, and choose the angle and range of osteotomy, increasing the precision, safety, and reliability of the procedure in various types of surgeries. It simplifies the difficult surgical steps and accelerates the growth of young and mid-career physicians. But some problems such as cost, materials, and equipment limit its development.ConclusionsIn different fields of orthopedics, the use of guide templates can significantly improve surgical accuracy, shorten the surgical time, and reduce intraoperative bleeding and radiation. With the development of 3D printing, the guide template will be standardized and simplified from design to production and use. 3D printing guides will be further sublimated in the application of orthopedics and better serve the patients.The translational potential of this paperPrecision, intelligence, and individuation are the future development direction of orthopedics. It is more and more popular as the price of printers falls and materials are developed. In addition, the technology of meta-universe, digital twin, and artificial intelligence have made revolutionary effects on template guides. We aim to summarize recent developments and applications of 3D printing guide templates for engineers and surgeons to develop more accurate and efficient templates.

Agent-Based Simulation Disaster Evacuation Awareness on Night Situation in Aceh

In 2004 at least 230,000 people were victims of the Aceh tsunami disaster. To prevent the recurrence of many victims, the Aceh government held an evacuation exercise in 2008. To improve effectiveness dan reduce the cost reduction during evacuations drills, simulation is the best option. Agent-Based Modeling is a simulation program that was employed for tsunami evacuation in Aceh. This study on tsunami evacuation using agent-based modelling presented and evaluated the different control parameters that affect the evacuation rate. Evacuation scenario during day or night has different environmental, agent base, road modelling, and population approach. The Road Network Model has explained that to analyze the effect of agents in the evacuation process, resident agents are presumed to know the direction and shortest path to the nearest evacuation points. This simulation designed in Netlogo is also able to assess the congestion possibility on the road network. The road network emphasized the different scenarios to discover the possibility of congestion points. Nighttime is proven to be the best scenario for performing the evacuation in the simulation. The key reason to select the night scenario is to maximize the effects of an evaluation of the road network. In addition, simulation using night scenarios is also expected to raise people’s awareness.

Subsurface Investigation of Voids using Ground Penetration Radar in Bismayah Site, Southern Baghdad, Central Iraq

Ground Penetration Radar investigation was used to survey the Bismayah pumping station site in Baghdad. The survey includes fifteen Ground Penetration Radar survey lines inside and outside the site, an antenna of 250 MHz was used. The total length of survey lines was about 706 m. The results of Ground Penetration Radar lines in outside station's radargrams exhibit reverberation events in the Ground Penetration Radar signal, it might be interpreted as the inverse of existing voids or noise near the surface. Grouted materials could be understood as the refractor. The results of the radargrams along the paths inside the pumping station revealed that the station collapsed in the north because the reflector of soil creep was visible in the north line path direction. After 4 m from the ground surface and right beneath the foundation base, there was a layer of loose dense river sand filled with water. It is expected that the process of soil creep caused the rush and drift of the pumping station structure towards the withdrawal of water from the well. The results show the efficiency of the Ground Penetration Radar technique in the near-surface investigation of the current study, due to the easy and time saving survey with reasonable results.

Flow Path of the Carbonate Geothermal Water in Xiong’an New Area, North China: Constraints From 14C Dating and H-O Isotopes

Studying the flow path of geothermal water in geothermal fields is an important basis for the scientific development and management of geothermal resources. However, due to the influence of engineering volume, economic benefits and demand, it is very difficult to fully grasp the flow path of deep geothermal water in large areas. The use of hydrogeochemical tracers to determine the flow path of geothermal water is a scientific and effective research method. In order to accurately describe the flow path of carbonate geothermal water in the Xiong’an New Area and its surrounding areas, this study systematically analyzed the 14C, 18O, and 2H data of carbonate and Cenozoic sandstone geothermal water, Quaternary groundwater, as well as mountain spring water of the study area. Based on these results, we can conclude that 1) The 14C, d, and 18O values are favourable clues for indicating the circulating runoff conditions and runoff paths of geothermal water. 2) The salinity of the Xushui-Wenan and Lilan transfer zone are <3 g/l, the 14C values are lower than 25000 years, the d value is higher, and the phenomenon of “18O drift” is weak, all these indicating the dominant flow path of carbonate geothermal water, featured by relative lower temperature. 3) The salinity of karst geothermal water in the southwest of Gaoyang low uplift, Rongcheng uplift and Niutuozhen uplift is > 3 g/l, the 14C values are higher than 40,000 years, the d value is lower, and the phenomenon of “18O drift” is obvious, all these indicating that the tectonic sites are the convergence areas of regional karst geothermal water, featured by relative high temperature. 4) The hydrochemical indicators combined with previous carbonate groundwater flow field indicate that the recharge of carbonate geothermal water in the Xiong’an New Area may not only drive from the western Taihang Mountains, but also along the Xushui-Wenan transfer zone and the Lilan fault, with the recharge of carbonate groundwater from the Cangxian uplift from east to west. By further identifying and defining the dominant flow path and supply direction of carbonate geothermal water in the Xiong’an New Area and surrounding areas, it provides strong support for the scientific development of regional carbonate geothermal water.

Tornado Radar Images and Path Directions: An Assessment of Public Knowledge in the Southeastern United States

Abstract Due to the current use and reliance on tornado warning polygons, several published articles have concentrated on themes related to risk perception and interpretation of risk within and outside of polygons. Despite the general success of warning polygons, not everybody is able to spatially estimate their risk by looking at maps with tornado warning polygons. Using polygons in conjunction with radar images can improve comprehension and better inform protective action decision-making for tornado warnings. Additionally, a potential latent area of research is how past tornado tracks and climatological knowledge about tornado path directions may influence tornado risk perception and protective action decision-making. In this study, we surveyed 1023 individuals across the southeastern United States. Participants were asked to rate their level of concern for a tornadic supercell moving toward two locations. They were also asked to name the direction tornadoes usually come from and travel toward in their counties. Results indicated significantly more concern about the radar reflectivity within the supercell than concern about the location of the hook echo. Additionally, the perceived directions of tornado paths across the region were inaccurate with 75 percent of the sample either not answering, indicating that they did not know the most common direction for tornado paths, or answering that tornadoes travel in uncommon or unrealistic path directions. The Atlanta metropolitan area was used as a case study to illustrate inaccurate perceptions of path directions.