bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generalized Method of Effective Field in Linear Peridynamic Micromechanics of Random Structure Composites
Authors: Buryachenko Valeriy A. 
Published: February 2021

Abstract
A statistically homogeneous random matrix medium with the bond-based peridynamic properties of constituents is considered. For the media subjected to remote homogeneous volumetric boundary loading, one proved that the effective behavior of this media is governing by conventional effective constitutive equation which is the same as for the local elasticity theory. The average is performed over the surface of the extended inclusion phase rather than over an entire space. Any spatial derivatives of displacement fields are not required. The basic hypotheses of locally elastic micromechanics are generalized to their peri-static counterparts. In particular, in the generalized method of effective field proposed, the effective field is evaluated from self-consistent estimations by the use of closing of a corresponding integral equation in the framework of the quasi-crystalline approximation. In so doing, the classical effective field hypothesis is relaxed, and the hypothesis of the ellipsoidal symmetry of the random structure of CMs is not used. One demonstrates some similarity and difference with respect to other methods (the dilute approximation and Mori-Tanaka approach) proposed before in peridynamic micromechanics of CMs. Comparative numerical analyses of these methods are performed for 1D case.
Automating Aircraft Exterior Inspection With Robotics and Machine Learning Technologies
Authors: Sun Yufeng , Ma Ou 
Published: February 2021

Abstract
Most aircraft exterior inspections require human workers to visually detect defects such as dents, cracks, leaking, broken or missing parts, etc., and manually measure the parameters of the identified defects, which is a time-consuming process and it is also error-prone if the human inspector is not fully focused. This situation can be alleviated by the advance in computer vision and robotics for saving time and relieving human workers from such repetitive and stressful tasks. However, the challenge of automated robotic inspection for aircraft exterior remains due to the very large inspected area, full-coverage requirement and sometimes insufficient digital model available for planning the inspection path. This paper presents a two-stage approach to automate visual inspection of aircraft exterior surface in a static environment such as a MRO shop by a mobile manipulator equipped with a consumer-grade RGB-D camera following an optimal inspection trajectory learned from a low-resolution point cloud model of the aircraft when a proper CAD model of the aircraft is unavailable. In the first stage, a low-cost RGB-D camera is used to acquire a coarse point cloud model of the whole or interested area of the aircraft. In the second stage, a full coverage inspection path is learned based on the coarse model using a reinforcement learning process, which is our focus of this work.
Optimization of Chessboard Scanning Strategy Using Genetic Algorithm in Multi-Laser Additive Manufacturing Process
Authors: Malekipour Ehsan , Valladares Homero , Shin Yung , El-Mounayri Hazim 
Published: February 2021

Abstract
Residual stress and manufacturing time are two serious challenges that hinder the widespread industry adoption and implementation of the powder-bed fusion (PBF) process. Commercial Multi-Laser PBF (ML-PBF) systems have been developed by several vendors in recent years, which dramatically increase the production rate by employing more heat sources (up to 4 laser beams). Although numerous research works conducted toward mitigation of the effects of residual stress on printed parts in the Single Laser PBF (SL-PBF) process, no research work on this topic has been reported for the ML-PBF process to date.
One of the most efficient real-time approaches to mitigate the influence of residual stress and as such the process lead time effectively is to improve the scanning strategy. This approach can be also implemented effectively in the ML-PBF process. In this work, we extend the previously developed GAMP (Genetic Algorithm Maximum Path) strategy for optimizing the scanning path in ML-PBF. The E-GAMP (the Extended GAMP) strategy manipulates the printing topology of the islands and generates more thermally efficient scanning patterns for the chessboard scanning strategy in ML-PBF. This strategy extends the single thermal heat source to multiple ones (2 as well as 3 lasers). To validate the effectiveness of the proposed strategy, we simulate the thermal distribution throughout a simple rectangular layer by ABAQUS for both the traditional successive scanning strategy and the E-GAMP strategy. The results demonstrate that the E-GAMP strategy considerably decreases the manufacturing time while it reduces the maximum temperature gradient, or in other words, generates a more uniform temperature distribution throughout the exposure layer.
Corrosion Evaluation of a Navy MK50 Weapon Station Friction Brake Assembly
Authors: Romsland Ruby , McDonald Kenneth J. 
Published: February 2021

Abstract
The presence of corrosion on or within structures is of major concern as corrosion reduces the integrity of the materials which could potentially result in large-scale failures of structures and equipment.1 The United States Navy is an organization that actively works to prevent large equipment failure due to corrosion. One such problem is the corrosion of the friction brake assembly on the MK50 Weapon Station, which has recently been experiencing corrosion between the friction brake and its set screw preventing it from operating correctly. The friction brake was known to be stainless steel; however, the set screw was of unknown composition. Through elemental analysis it was determined that the MK50 Weapons Station friction brake set screw was similar in composition to commonly available black oxide coated steel screws. Electrochemical polarization measurements of the friction brake assembly components revealed that the set screw and the friction brake were electrochemically dissimilar metals which resulted in the galvanic corrosion of the assembly when out at sea. The electrochemical polarization measurements of a stainless steel screw showed a corrosion potential similar to that of the friction brake; therefore, replacing the current set screw with a stainless steel screw would decrease the galvanic potential difference between the set screw and the friction brake. This proposed solution is expected to slow or prevent further corrosion of the MK50 Weapon Station ensuring the combat readiness of the equipment.
Effect of Alloying Elements Concentration and Processing Parameters on the Structural and Mechanical Properties of Lightweight Magnesium Alloys
Authors: Rawles Jessica , Fialkova Svitlana , Xu Zhigang , Sankar Jagannathan 
Published: February 2021

Abstract
Magnesium is utilized as a light-weight metal in the aerospace and automotive industries, and recently draws a lot of attention in biomedical research due to its biodegradable and biocompatible properties [1–3]. With Zinc being a biocompatible element, magnesium-zinc alloys have been very attractive for such applications.
Mechanical properties including yield strength, tensile strength and hardness values of magnesium alloys are reported to be improved with the adding of alloying elements such as Zn, Zr, Al, Y and some rare earth elements.
In our study we observe the improvement of mechanical properties Vicker’s Hardness (VH) for Mg-Zn-Ca alloys with a fixed content of calcium and varying amounts of zinc alloying elements.
Potential Outcome:
Potentially new developed alloys could be used for lightweight materials for aerospace, automotive, and biomedical application.
Conceptual Design of an In-Pipe Displacement System Applicable for Oil Well Production Column
Authors: Figliuolo Saulo Queiroz , Beal Valter Estevão , Mascarenhas Luis Alberto Breda , Romero Albino Juan Carlos , Santos Hugo Francisco Lisboa 
Published: February 2021

Abstract
Oil well production rate should be maintained during its lifecycle and maintenance interventions are necessary to reach this goal. Production engineer teams work on different ways to make the production stable and to enhance the oil recovery from the reservoirs. However, interventions are necessary to maintain or recover the production rate. Some problems that cause maintenance are malfunctioning/wear of equipment, clogging/obstruction and operational mistakes. These maintenances are required using expensive equipment, especially on offshore operations.
In order to reduce the overall cost of interventions, robotic systems have been proposed. In this work, a conceptual development for a robotic production column well intervention system is proposed. This equipment should be strong enough to resist oil well environmental characteristics. Nowadays, the challenge involves high pressure and high temperature wells, high flow rates, a long/deep well and other very hostile features. Even though, this device has to be very slim and lightweight because it will be responsible for carrying on other systems (measurement / inspection tools, completion tools, etc.) displacing into the oil well production column. On the other hand, it needs to have highly efficient power consumption since the power availability is usually limited in the actuation environment of this autonomous equipment.
In order to guarantee the achievement of the desirable requirements, the design team followed the best practices of the product development process aided by a design for lifecycle guidelines.
Low Cost Cooling Device for High Power LED Lamps
Authors: Martinez-Vega Pamela , Lopez-Badillo Araceli , Luviano-Ortiz J. Luis , Hernandez-Guerrero Abel , Cervantes Jaime G. 
Published: February 2021

Abstract
The modern world progressively demands more energy; according to forecasts energy consumption will grow at an average annual rate of 3 percent. Therefore, it is necessary to purchase products or devices that are efficient and environmentally friendly. Technology in LED (Light Emitting Diode) lighting is presented as an alternative to energy saving, since LEDs have proven to be extremely efficient, have a long service life and their cost-effective ratio is very good. However, the heat emitted by the LED chip must be dissipated effectively, since the overheating of the chip reduces the efficiency and lifetime of the lamp. Therefore, heat sinks that are reliable, efficient and inexpensive should be designed and built. The present work proposes new designs for heat sinks in LED lamps, some of the models in the design of the fins refer to the Fibonacci series. The models proposed in the present work that have a significant advantage are the Type 1E Model (5.2% mass savings and better thermal efficiency of 8.33%), GR Type 1 Model (3.12% lighter and 3.33% more efficient) and the GRL Type Model (4. 51% mass savings and 5.55% thermally more efficient) compared to the Type 2 Reference Model proposed by Jang et al. [12].
Load Distributions in Bolted Single Lap Joints Under Non-Central Tensile Shear Loading
Authors: Sinthusiri Chaiwat , Nassar Sayed A. 
Published: February 2021

Abstract
This study uses beam theory-based model to investigate a numerically calibrated bolt load distributions in a preloaded two-bolt single lap joint under non-central tensile shear loading. Linear spring-based modeling is used for the two preloaded bolts and substrates. In practice, due to geometric tolerance may not necessarily pass through the joint centerline causing an additional moment loading. Thus, the sharing load would not be equally distributed between all the bolt in the joint. The effect of various joint parameter, bolt preload and off-center location of the tensile shear loading is investigated and discussed. Proposed model would be useful in enhancing the reliability and safety of bolted joints.
Numerical Modeling and Analysis to Formulate Mechanical and Tactile Behavior of Skin
Authors: Yamamoto Tomohisa , Sakuma Atsushi 
Published: February 2021

Abstract
Tactile sensation by touching motion is one of the basic functions for human beings to recognize the characteristics and information of objects. It is known that information about touched objects is recognized through deformation of the skin, but it is difficult to physically clarify the mechanism of such sensations. In addition, there are several types of mechanoreceptors related to tactile sensation in human skin, and it is necessary to digitize the sensation in consideration of its response characteristics. The purpose of this study is to propose the product design method that recalls physical properties from mechanical information inside the skin in order to evaluate the relationship between human skin deformation and physical properties of touched objects. Humans can recognize the shape and softness of an object by pressing the skin against the surface of the object. The behavior inside the skin can be discussed by modeling the contact between human skin and rigid sphere and analyzing it mechanically by numerical simulation. Finite element method (FEM) was adopted as the numerical analysis method for this elucidation, and the three-layer laminated solid having the epidermis, dermis, and subcutaneous was developed as the numerical model, and mechanical information inside the skin was discussed.
The Effectiveness of Equipment Provisions on Rural Middle School Students’ Physical Activity During Lunch Recess
Authors: Yu Hyeonho , Kulinna Pamela H. , Mulhearn Shannon C. 
Published: February 2021

Background: Environmental provisions can boost students’ discretionary participation in physical activity (PA) during lunchtime at school. This study investigated the effectiveness of providing PA equipment as an environmental intervention on middle school students’ PA levels and stakeholders’ perceptions of the effectiveness of equipment provisions during school lunch recess. Methods: A baseline–intervention research design was used in this study with a first baseline phase followed by an intervention phase (ie, equipment provision phase). A total of 514 students at 2 middle schools (school 1 and school 2) in a rural area of the western United States were observed directly using the System for Observing Play and Leisure Activity in Youth instrument. Interviews were conducted with stakeholders. Paired-sample t tests and visual analysis were conducted to explore differences in PA levels by gender, and common comparison (with trustworthiness measures) was used with the interview data. Results: The overall percentage of moderate to vigorous PA levels was increased in both schools (ranging from 8.0% to 24.0%). In school 2, there was a significant difference in seventh- and eighth-grade students’ moderate to vigorous PA levels from the baseline. Three major themes were identified: (1) unmotivated, (2) unequipped, and (3) unquestionable changes (with students becoming more active). Conclusions: Environmental supports (access, equipment, and supervision) significantly and positively influenced middle school students’ lunchtime PA levels.
Perceived hazardous physical work environments and job-related affective well-being of navy officers aboard the Republic of Korea Navy ships and submarines in South Korea
Authors: Jo Doseon , Koh C K 
Published: February 2021

IntroductionNavy ships and submarines are important military measures that protect the Republic of Korea. They also comprise naval officers’ workplace. However, few studies have examined naval officers’ working environment and their job-related well-being. This study aimed to explore exposure to hazardous work environments among navy officers aboard ships and submarines and their association with job-related affective well-being.MethodsThis was a cross-sectional descriptive study. The sample comprised 146 officers from 4 navy ships and 98 officers from 5 submarines. Items of exposure to the eight types of hazardous work environments and the Job-related Affective Well-being Scale (JAWS) were included in the self-report survey questionnaires.ResultsThe most common hazards reported by officers aboard navy ships were vibration (63.7%) and air pollution (56.2%). For submarine officers, these hazards were lack of personal space (72.4%) and air pollution (67.3%). The average JAWS score for ship officers and submarine officers was 69.81 (SD=10.89) and 70.50 (SD=10.83), respectively. For ship officers, exposure to air pollution, noise, vibration, thermal discomfort during summer or winter and lack of personal space were significantly correlated with lower JAWS scores. For submarine officers, exposure to fire, burning or electrical shock, air pollution, noise, thermal discomfort during summer or winter and lack of personal space were significantly correlated with lower JAWS scores.ConclusionsThis study revealed that some naval officers aboard ships or submarines are exposed to hazardous work environments. Moreover, certain types of hazardous work environments were associated with naval officers’ job-related affective well-being.
Suicide capacity within the ideation-to-action framework: a scoping review protocol
Authors: Bayliss Luke T , Lamont-Mills Andrea , du Plessis Carol , Morgan Talia 
Published: February 2021

IntroductionA core facilitator of the transition from suicidal thoughts to suicide attempt is the individual’s capacity for suicide. Suicide capacity is a theoretically universal concept adaptable for specific groups that is hypothesised to comprise three contributing factors: acquired capability, for example, previous self-harm; dispositional, such as genetic influences and practical, knowledge of and access to lethal means. Given that suicide capacity as a concept is continuing to develop, a review and synthesis of the current literature is timely to ensure future research and development of suicide prevention strategies are based on evidential knowledge. The aim of this review is to map the available evidence to provide an overview of factors that contribute to an adult’s capacity for suicide.Methods and analysisThis review will encompass five stages. Studies will be identified through broad search strings applied to 11 academic databases: Academic Search Ultimate, APA PsycArticles, APA PsycINFO, CINAHL, Psychology & Behavioural Sciences, & Sociology Source Ultimate via EBSCOHost Megafile Ultimate; PubMed; Science Direct; Wiley Online; Taylor & Francis and ProQuest dissertations and theses. Grey literature databases and key suicide organisations will also be searched for relevant literature. Two reviewers will independently screen titles and abstracts then review full texts to identify articles meeting inclusion criteria. Articles will be assessed for eligibility based on suicide attempt history, primary research study design, language and publication date. Data from eligible full texts will be extracted using a predesigned template for analysis. The synthesisation method will be textual narrative synthesis with an incorporated quality appraisal checklist tool.Ethics and disseminationEthics approval is not required for this scoping review as no human participants are involved. Study findings will be shared with key suicide organisations, through peer-reviewed publications, and conference presentations.
Recreational substance use among patients with premature atherosclerotic cardiovascular disease
Authors: Mahtta Dhruv , Ramsey David , Krittanawong Chayakrit , Al Rifai Mahmoud , Khurram Nasir , Samad Zainab , Jneid Hani , Ballantyne Christie , Petersen Laura A , Virani Salim S 
Published: February 2021

ObjectiveDespite an upsurge in the incidence of atherosclerotic cardiovascular diseases (ASCVD) among young adults, the attributable risk of recreational substance use among young patients has been incompletely evaluated. We evaluated the association of all recreational substances with premature and extremely premature ASCVD.MethodsIn a cross-sectional analysis using the 2014–2015 nationwide Veterans Affairs Healthcare database and the Veterans wIth premaTure AtheroscLerosis (VITAL) registry, patients were categorised as having premature, extremely premature or non-premature ASCVD. Premature ASCVD was defined as having first ASCVD event at age <55 years for men and <65 years for women. Extremely premature was defined as having first ASCVD event at age <40 years while non-premature ASCVD was defined as having first ASCVD event at age ≥55 years for men and ≥65 years for women. Patients with premature ASCVD (n=135 703) and those with extremely premature ASCVD (n=7716) were compared against patients with non-premature ASCVD (n=1 112 455). Multivariable logistic regression models were used to study the independent association of all recreational substances with premature and extremely premature ASCVD.ResultsCompared with patients with non-premature ASCVD, patients with premature ASCVD had a higher use of tobacco (62.9% vs 40.6%), alcohol (31.8% vs 14.8%), cocaine (12.9% vs 2.5%), amphetamine (2.9% vs 0.5%) and cannabis (12.5% vs 2.7%) (p<0.01 for all comparisons). In adjusted models, the use of tobacco (OR 1.97, 95% CI 1.94 to 2.00), alcohol (OR 1.50, 95% CI 1.47 to 1.52), cocaine (OR 2.44, 95% CI 2.38 to 2.50), amphetamine (OR 2.74, 95% CI 2.62 to 2.87), cannabis (OR 2.65, 95% CI 2.59 to 2.71) and other drugs (OR 2.53, 95% CI 2.47 to 2.59) was independently associated with premature ASCVD. Patients with polysubstance use had a graded response with the highest risk (~9-fold) of premature ASCVD among patients with use of ≥4 recreational substances. Similar trends were observed among patients with extremely premature ASCVD. Gender interactions with substance use were significant (p-interaction <0.05), with recreational substance use and premature ASCVD showing stronger associations among women than in men with premature ASCVD.ConclusionsAll subgroups of recreational substances were independently associated with a higher likelihood of premature and extremely premature ASCVD. Recreational substance use confers a greater magnitude of risk for premature ASCVD among women. A graded response relationship exists between increasing number of recreational substances used and higher likelihood of early-onset ASCVD.
CLINICAL AND ULTRASONOGRAPHIC CORRELATION OF PES ANSERINUS BURSITIS
Authors: Deepak Joshi Ameya , Gupta Shefali , Shukla Aradhana , Gaur Anil K. 
Published: February 2021

Purpose: Pes anserinus bursitis is a commonly overlooked cause of medial knee pain. It is diagnosed clinically and involves tendons/bursa or both. Majority of studies fail to provide imaging evidence of tendon/bursal pathology in clinically diagnosed patients. This study documents the ultrasonographic findings associated with clinically diagnosed pes anserinus bursitis and correlates between clinical and positive ultrasonographic findings. Methods: A cross-sectional study was done in outpatient department settings of physical medicine and rehabilitation department in participants with clinically diagnosed pes anserinus bursitis. Clinically evaluation was done by Physiatrist and ultrasonographic evaluation by a radiologist. Patient characteristics, clinical findings and ultrasonographic features were documented and studied. Results: In the evaluated 67 knees, Pes anserinus tendonitis (53.73%) with statistical significance ([Formula: see text].0001) was found on ultrasonography over bursitis (2.99%). Abnormal findings involving medial collateral ligament (38.81%), medial meniscus (26.87%), suprapatellar recess (47.76%), and other structures (17.91%) were also documented. Age, gender, body mass index, and duration had no effect on presence of positive ultrasonographic findings. Conclusion: Ultrasonographic changes of tendonitis involving pes anserinus tendons correlate with clinically diagnosed pes anserinus bursitis. The ultrasonography also helps in identifying potential sources of pain other than pes anserinus tendon or bursa in such cases.