bluuebunny/crossref_metadata_2025 huggingface dataset:
Digital servitization journey in small- and medium-sized enterprises: the contribution of knowledge-intensive business firms
Authors: Rapaccini Mario , Paiola Marco , Cinquini Lino , Giannetti Riccardo
Published: February 2023

Purpose

This study aims to investigate the contribution of knowledge-intensive business services firms to small- and medium-sized manufacturers’ digital servitization journeys, addressing the standardization versus customization dichotomy of services and solutions provision.

Design/methodology/approach

To identify the challenges that small- and medium-sized firms must face in the digital servitization journey and the role that knowledge-intensive business services firms may play in the innovation processes, the authors conduct a review on two still unrelated literature streams and develop a longitudinal single-case study, with a particular focus on knowledge generation mechanisms.

Findings

Digital servitization is a particularly challenging transformational journey for minor firms. Knowledge-intensive business services firms can act as sources, facilitators, and carriers of knowledge, and they can orchestrate further contributions of other external partners and firms.

Research limitations/implications

The paper contributes to theory describing the roadmap and the role of external service providers in digital servitization journeys of smaller firms’, that are frequently excluded from mainstream research although being the backbone of European economies.

Practical implications

Digital servitization in minor manufacturing firms requires a long-term orientation and a multi-stage roadmap. Mixing standardized technology-based solutions and complementary professional services, knowledge-intensive business services firms can significantly contribute to lowering the journey’s uncertainties, operational complexity, and costs.

Originality/value

The paper sheds lights on how the collaboration between knowledge-intensive business services firms and small manufacturers generates novel knowledge and capabilities that contribute to takle the challenges of the different stages of the digital servitization roadmap.
Inclusive leadership and innovative work behaviors: a moderated mediation model
Authors: Sürücü Lütfi , Maslakçı Ahmet , Şeşen Harun
Published: February 2023

Purpose

This research aimed to determine how and why inclusive leadership is effective in innovative work behaviors (IWBs). For this purpose, a conceptual model including inclusive leadership, IWBs, psychological resilience capacity and leader–member exchange (LMX) has been proposed.

Design/methodology/approach

To test the proposed model, a questionnaire was administered to the employees of a Turkish telecommunications company located in Istanbul and Ankara. Data obtained from 459 employees selected by convenience sampling method were analyzed using SPSS-24 and PROCESS macro.

Findings

The results show that inclusive leadership has a positive effect on IWBs through psychological resilience capacity. Additionally, it has been determined that LMX plays a moderated mediation role in this relationship.

Originality/value

The research model, which is a new attempt in the literature, contributes to filling a significant gap in leadership research and presents a holistic perspective to readers and practitioners in understanding the effects of the inclusive leader on IWBs by testing the moderated mediation effect of LMX.
Inputs of seabird guano alter microbial growth, community composition and the phytoplankton–bacterial interactions in a coastal system
Authors: Justel‐Díez Maider , Delgadillo‐Nuño Erick , Gutiérrez‐Barral Alberto , García‐Otero Paula , Alonso‐Barciela Isaac , Pereira‐Villanueva Pablo , Álvarez‐Salgado Xosé Antón , Velando Alberto , Teira Eva , Fernández Emilio
Published: February 2023

Seabird guano enters coastal waters providing bioavailable substrates for microbial plankton, but their role in marine ecosystem functioning remains poorly understood. Two concentrations of the water soluble fraction (WSF) of gull guano were added to different natural microbial communities collected in surface waters from the Ría de Vigo (NW Spain) in spring, summer, and winter. Samples were incubated with or without antibiotics (to block bacterial activity) to test whether gull guano stimulated phytoplankton and bacterial growth, caused changes in taxonomic composition, and altered phytoplankton–bacteria interactions. Alteromonadales, Sphingobacteriales, Verrucomicrobia and diatoms were generally stimulated by guano. Chlorophyll a (Chl a) concentration and bacterial abundance significantly increased after additions independently of the initial ambient nutrient concentrations. Our study demonstrates, for the first time, that the addition of guano altered the phytoplankton–bacteria interaction index from neutral (i.e. phytoplankton growth was not affected by bacterial activity) to positive (i.e. phytoplankton growth was stimulated by bacterial activity) in the low‐nutrient environment occurring in spring. In contrast, when environmental nutrient concentrations were high, the interaction index changed from positive to neutral after guano additions, suggesting the presence of some secondary metabolite in the guano that is needed for phytoplankton growth, which would otherwise be supplied by bacteria.
The effect of social skills on analyst performance
Authors: Li Congcong , Lin An‐Ping , Lu Hai
Published: February 2023

Social skills are important but difficult to measure. So far, few empirical studies have examined the effect of social skills on the performance of professionals. Using the number of LinkedIn connections as a proxy for social skills, we investigate the effect of financial analysts' social skills on their performance. We use multiple ways to validate the measure of social skills and show that analysts with better social skills produce more accurate earnings forecasts and that their stock recommendations elicit stronger market reactions. Furthermore, these socially skilled analysts are more likely to be voted as All‐Star Analysts. This study provides the first large‐sample evidence highlighting the importance of social skills on financial analysts' performance.
Association between neighborhood deprivation and mortality in patients with schizophrenia and bipolar disorder—A nationwide follow‐up study
Authors: Jansåker Filip , Sundquist Jan , Sundquist Kristina , Li Xinjun
Published: February 2023

Objectives

The aim was to explore the association between neighborhood deprivation and all‐cause mortality and cause‐specific mortalities in patients with schizophrenia and bipolar disorder. A better understanding of this potential relationship may help to identify patients with schizophrenia and bipolar disorder with an increased mortality risk.

Methods

This nationwide study included practically all adults (≥30 years) diagnosed with schizophrenia (n = 34,544) and bipolar disorder (n = 64,035) in Sweden (1997–2017). The association between neighborhood deprivation and mortality was explored using Cox regression. All models were conducted in both men and women and adjusted for individual‐level sociodemographic factors and comorbidities.

Results

There was an association between level of neighborhood deprivation and all‐cause mortality in both groups. The adjusted hazard ratios for all‐cause mortality associated with high compared to low neighborhood deprivation were 1.18 (95% confidence interval 1.11–1.25) in patients with schizophrenia and 1.33 (1.26–1.41) in patients with bipolar disorder. The two most common mortality causes in both groups were coronary heart disease and cancer. The mortality due to coronary heart disease increased when neighborhood deprivation increased and reached 1.37 (1.18–1.60) in patients with schizophrenia and 1.70 (1.44–2.01) in patients with bipolar disorder living in the most deprived neighborhoods.

Conclusions

This study shows that neighborhood deprivation is an important risk factor for all‐cause mortality and most cause‐specific mortalities among patients with schizophrenia and bipolar disorder. These findings could serve as aid to policymakers when allocating healthcare resources and to clinicians who encounter patients with these conditions in deprived neighborhoods.
Bypassing of nearest labor & delivery unit is contingent on rurality, wealth, and race
Authors: Carrel Margaret , Keino Barbara C. , Novak Nicole L. , Ryckman Kelli K. , Radke Stephanie
Published: February 2023

Patient decisions to bypass the closest labor & delivery (L&D) facility in favor of other birthing locations can have consequences for the provision of health care in rural and micropolitan areas as patient volumes decline and payer mixes change. Among 220 589 uncomplicated births in Iowa, we document characteristics of birth parents who bypass their closest birthing facility, show how this bypassing behavior results in changed travel times to delivery facilities across the rural/urban divide, and indicate the parts of the state where bypassing behavior is most prevalent. From 2013 to 2019, 55.2% of deliveries occurred in facilities that were further from birthing parents' residences than the closest L&D facility. Bypassing is associated with White, non‐Hispanic race/ethnicity, and private insurance status. Although bypassing is least common among micropolitan birth parents, this group has the greatest travel burden to birthing facilities and exhibits increasing rates of bypassing over time. Perinatal quality improvement programs can target locations and populations where low‐risk birthing parents can be encouraged to deliver close to home if medically appropriate, particularly in small towns and rural areas. This can potentially alleviate the risk of obstetric deserts by ensuring L&D units maintain patient volumes necessary to continue operations.
Behavioural medicine theory‐based intervention strategies for promoting oral health
Authors: Wilson Dawn K.
Published: February 2023

Objectives

The field of Behavioural Medicine offers strategies that can minimize the need for more intensive medical treatments and can improve outcomes of these treatments and adherence to medication prescriptions or postsurgical recommendations. Thus, this paper provides scientific evidence and examples of behavioural and motivational strategies for improving adherence to oral health recommendations.

Methods

Increasing evidence from randomized controlled trials suggests that improving self‐regulation, autonomous motivation and social environmental supports for adherence are critical for improving a wide range of behaviours including oral health behaviours. Theory‐based interventions including Social Cognitive Theory (behavioural strategies) and Self‐determination theory (motivational strategies) are described and examples of their effectiveness are provided specific to oral health outcomes.

Results

Social Cognitive Theory provides a framework for building skills and self‐efficacy (self‐confidence, competence, mastery and self‐regulation) through developing action plans that target goal setting, monitoring and positive feedback within the context of providing support. Behavioural strategies, including self‐monitoring, goal setting and skill building, are all important elements for promoting long‐term lifestyle changes by targeting increases in self‐efficacy and mastery (self‐confidence and self‐regulation skills). Motivational interviewing and positive communication strategies are also discussed specific to improving oral health outcomes.

Conclusions

In sum, behavioural medicine provides an opportunity and framework for supporting patients/individuals to achieve changes in target health behaviours, including oral health recommendations.
Perceptions of the COVID‐19 pandemic's impact on communities and wildlife trade: Preliminary qualitative analysis from hunters in Vietnam, Cambodia, and Laos
Authors: Davis Elizabeth Oneita , Castaneda Marielle , Crudge Brian , Lim Thona , Roth Vichet , Glikman J. A. , Cao Trung
Published: February 2023

The COVID‐19 pandemic has accelerated efforts to engage critically with forest‐adjacent, rural, communities who rely on wildlife. We interviewed 109 hunters of wildlife across Vietnam, Cambodia, and Laos regarding the effect the COVID‐19 pandemic has had on them, as well as within their communities. We found that “negative economic impacts” was a prevalent theme due to loss of employment, rising prices, and restrictions on trade resulting from city‐wide lockdowns, factory closures, and border closures. In Vietnam, hunting was stated to have increased as young men returned to their villages; however, in Vietnam and Cambodia trade in wildlife was believed to have decreased due to the inability of middlemen traders to travel easily. Our results from Laos illustrated general economic cost, but otherwise no impact of COVID‐19 on hunting and trade in wildlife. Here, we show the complex impacts of a pandemic, with contextually specific conservation positives (such as decreased trade), and conservation negatives (such as increased hunting to supplement loss of employment). We illustrate the importance of establishing sustainable, non‐wildlife‐dependent livelihoods within rural communities, to mitigate hunting and the potential for disease transmission, and the value in engaging with hunters to understand locally and spatially specific trends in global conservation challenges.
Low species turnover of upland Amazonian birds in the absence of physical barriers
Authors: Rutt Cameron L. , Cooper W. Justin , Andretti Christian B. , Costa Thiago V. V. , Stouffer Philip C , Vargas Claudeir F. , Luther David A. , Cohn‐Haft Mario
Published: February 2023

Aim

One of the oldest and most powerful ways for ecologists to explain distinct biological communities is to invoke underlying environmental differences. But in hyper‐diverse systems, which often display high species richness and low species abundance, these sorts of community comparisons are especially challenging. The classic view for Amazonian birds posits that riverine barriers and habitat specialization determine local and regional community composition. We test the tacit, complementary assumption that similar bird communities should therefore permeate uniform habitat between major rivers, regardless of distance.

Location

Upland (terra firme) rainforests of central Amazonia.

Methods

We conducted intensive whole‐community surveys of birds in three pairs of 100‐ha plots, separated by 40–60 km. We then used dissimilarity indices, cluster analysis, and ordination to characterize differences among the six avian communities.

Results

In all, we detected 244 forest‐dependent birds, with an average of 190 species (78%) per plot. Species turnover was negligible, no unique indicator species were found among plot pairs, and all documented species were already known from a complete inventory at one of the three sites.

Main Conclusions

Our study corroborates the classic biogeographical pattern and suggests that turnover contributes little to regional avian diversity within upland forests. Using a grain size of 100 ha, this implies that upland birds perceive the environment as uniform, at least over distances of ~60 km. Therefore, to maximize both local species richness and population persistence, our findings support the conservation of very large tracts of upland rainforest. Our analyses also revealed that the avifauna at Reserva Ducke, encroached by urban sprawl from the city of Manaus, shows the hallmarks of a disturbed community, with fewer vulnerable insectivores. This defaunation signals that even an enormous preserve (10 × 10 km) in lowland Amazonia is not insulated from anthropogenic degradation within the surrounding landscape.
Commentary: Natural disaster studies on prenatal stress – moving forward – a commentary/reflection on Nomura et al. (2023)
Authors: de Weerth Carolina
Published: February 2023

This commentary is based on the premise that the goal of scientific publications is to advance knowledge and inspire scientific discussion. First, the Nomura et al. paper is briefly summarized and shortly discussed to illustrate some of the challenges faced in this field, and suggestions for improvement are made. Then, the reader is invited to take a step back and reflect on how to continue investigating the effects of natural disasters on pregnant women and their children in the best possible manner. Additional suggestions are made for much‐needed research on other types of severe maternal prenatal stress and on high‐quality interventions for natural disasters. The goal is to stimulate reflection and exchange so that future choices made by researchers, funding bodies, and policymakers lead to substantial advances in the field of prenatal stress.
Does Monetary Policy Affect Income Inequality in the Euro Area?
Authors: SAMARINA ANNA , NGUYEN ANH D.M.
Published: February 2023

This paper examines how the ECB's expansionary monetary policy affects income inequality in 10 euro area countries over the period 1999–2014. We distinguish two channels—labor‐market and financial—through which monetary policy can have distributional effects. The labor‐market channel is captured by wages and employment and the financial channel by asset prices and returns. We find that expansionary monetary policy in the euro area reduces income inequality, especially in the periphery countries. The labor‐market channel enhances the equalizing effect: monetary expansion reduces income inequality stronger by raising wages and employment. There is limited evidence for the financial channel.
Non‐surgical rhinoplasty technique: An innovative approach for nasal reshaping with hyaluronic acid fillers
Authors: Giammarioli Giulio , Liberti Alberto
Published: February 2023

Objective

Nonsurgical rhinoplasty has become increasingly popular among patients who want to improve the aesthetic aspects of their nose and do not accept the risks and/ or cost of surgical rhinoplasty. The main goal of the current paper was to present the preliminary aesthetic and clinical outcomes of an innovative injection technique for nose sculpturing with hyaluronic acid (HA) filler.

Methods

Retrospective analysis of a prospective clinical registry of patients who attended one of the study centers and were candidates for non‐surgical nose reshaping between October 2019 and November 2020. A 25 mg/mL HA filler was administered, in all the cases, by using a syringe with a fixed microneedle (30G/8mm). All patients were injected at three key nose points with the following order: (1) Tip (maximum HA injected 0.2 mL); (2) columella (maximum HA injected 0.3 mL); and (3) Radix and Dorsum (maximum HA injected 0.3 mL). Degree of patient satisfaction with the treatment was assessed by using a five‐points Likert scale. The primary endpoint was the degree of patients' satisfaction 12 months after treatment.

Results

One‐hundred‐and‐one patients (91 women) were included in the study. Fifty‐six (56%) patients underwent a unique treatment‐session and 44 (44%) subjects needed an additional touch‐up. Eighty‐five (84.2%) patients were very satisfied with the treatment results. Six (5.9%) patients reported moderate adverse events, which were successfully controlled with medical therapy.

Conclusions

Our nose sculpturing technique, by using hyaluronic acid filler, was an effective, predictable, and relatively safe procedure, that obtained a high degree of patient satisfaction.
Assessing the CO2 concentration at the surface of photosynthetic mesophyll cells
Authors: Márquez Diego A. , Stuart‐Williams Hilary , Cernusak Lucas A. , Farquhar Graham D.
Published: February 2023

We present a robust estimation of the CO2 concentration at the surface of photosynthetic mesophyll cells (cw), applicable under reasonable assumptions of assimilation distribution within the leaf. We used Capsicum annuum, Helianthus annuus and Gossypium hirsutumas model plants for our experiments.

We introduce calculations to estimate cw using independent adaxial and abaxial gas exchange measurements, and accounting for the mesophyll airspace resistances.

The cw was lower than adaxial and abaxial estimated intercellular CO2 concentrations (ci). Differences between cw and the ci of each surface were usually larger than 10 μmol mol−1. Differences between adaxial and abaxial ci ranged from a few μmol mol−1 to almost 50 μmol mol−1, where the largest differences were found at high air saturation deficits (ASD). Differences between adaxial and abaxial ci and the ci estimated by mixing both fluxes ranged from −30 to +20 μmol mol−1, where the largest differences were found under high ASD or high ambient CO2 concentrations.

Accounting for cw improves the information that can be extracted from gas exchange experiments, allowing a more detailed description of the CO2 and water vapor gradients within the leaf.
Muscle fatigue during maximal eccentric‐only, concentric‐only, and eccentric‐concentric bicep curl exercise with automated drop setting
Authors: Nuzzo James L. , Pinto Matheus D. , Nosaka Kazunori
Published: February 2023

Connected adaptive resistance exercise (CARE) machines are new technology purported to adjust resistance exercise loads in response to muscle fatigue. The present study examined muscle fatigue (strength loss, fatigue perceptions) during maximal eccentric‐only (ECCmax‐only), concentric‐only (CONmax‐only), and coupled ECC‐CON (ECCmax‐CONmax) bicep curl exercise on a CARE machine. Eleven men and nine women completed the three protocols in separate sessions and in random order. All protocols included 4 sets of 20 maximal effort muscle contractions. Strength loss was calculated as Set 4 set end load minus Set 1 highest load. The CARE machine's algorithm adjusted resistances automatically, permitting continued maximal effort repetitions without stopping. Consequently, all protocols caused substantial fatigue. Women were most susceptible to strength loss from exercise that included maximal efforts in the ECC phase, whereas men were most susceptible to strength loss from exercise that included maximal efforts in the CON phase. With ECCmax‐only exercise, ECC strength loss (mean ± SD) was similar between men (55.9 ± 14.1%) and women (56.4 ± 10.8%). However, with CONmax‐only exercise, men and women experienced 55.6 ± 6.2% and 35.3 ± 8.7% CON strength loss, respectively. With ECCmax‐CONmax exercise, men experienced greater ECC (62.9 ± 7.7%) and CON (77.0 ± 5.3%) strength loss than women (ECC: 48.5 ± 15.7%, CON: 66.2 ± 12.1%). Heightened perceptions of fatigue and pain of the exercised limb were reported after all protocols. Women generally reported more biceps pain than men. The results illustrate CARE technology delivers ECC‐only and accentuated ECC exercise feasibly. Acute responses to repeated maximal effort bicep curl exercise with such technology might differ between men and women depending on muscle contraction type.
Engine Mounting Systems for Electric Powertrains: Mounting Layouts and Design Parameters
Authors: Kaul Sudhir
Published: February 2023

The vibroacoustic characteristics of electric powertrains are well known to significantly differ from internal combustion engines. A relatively very high power-to-torque density makes a three-phase permanent-magnet synchronous motor (PMSM) very appealing for electric powertrains, but its electromagnetic characteristics typically result in high frequency noise and vibration. While the vibration response in internal combustion engines is generally evaluated up to 100 Hz, electric drive trains are known to exhibit a response ranging from 1 to 10 kHz. As a result, multiple studies in the recent literature have investigated several designs for engine mounting systems that could be used to address some of the specific issues such as internal resonances, wave effects, high frequency noise and vibration, etc. It has been widely reported in the literature that force transmissibility and noise radiation can be significantly underestimated at relatively higher frequencies without directly modeling the inertial properties of the engine mounting system. Some of the mounting system layouts that have been investigated in the literature include the three-point or four-point saddle mounting configurations, the cradle type pendulum mounting configuration, etc. This paper performs a comparative analysis for a few of the commonly used mounting system layouts to identify the pros and cons of the design strategies specifically aimed at vibration mitigation in electric powertrains. A spatial model that has been previously validated is used to compare three different mounting system layouts. Since viscoelastic properties are known to exhibit a strong influence from excitation frequencies, the spatial model that has been used in this study incorporates the properties that are associated with high frequency response of the engine mounting system. Force transmissibility plots are used to evaluate the mounting layouts and specific design parameters associated with the engine mounting system. Results indicate that the four-point saddle mounting configuration provides a good balance between transmissibility at low frequencies and high frequencies. Models presented in this study can be used to determine an optimal mounting configuration for an electric powertrain.
Testing of an Articulated Prosthetic Ankle
Authors: Davidson Michael , Daher Noha , Dudley Robert , Fryer Thomas , Schaepper Johannes , Tran Duc
Published: February 2023

This paper presents our initial evaluation of a prototype ankle prosthesis with a one degree-of-freedom joint-axis featuring a biologically correct joint-axis alignment with hydro-pneumatic passive-resistance. The purpose of this biomedical device is to improve stance stability, increase balance confidence, and reduce the contralateral limb’s kinetic stresses in gait, sitting, and standing. The objective of this case study was to test the safety and feasibility of the device on an active single-limb male amputee. A single subject with a trans-tibial amputation was fitted with the prototype ankle prosthesis and tested against his prescribed daily use prosthesis. In addition to extended walking on level ground, kinematic and kinetic measures were taken in an 18-camera motion capture lab with two in-floor force platforms. These measures assessed body symmetry in the timed-up and go (TUG) test and five times the sit-to-stand (5xSTS) test while the subject used this prototype device. Balance confidence was assessed using the activities-based balance confidence (ABC) questionnaire. While performing the 10MWT, the subject was able to ambulate at a maximum velocity of 1.34 m/s and an average of 1.32 m/s. In the six-minute walk test (6MWT), the subject was able to walk a distance of 416.84 meters (a velocity of 1.16m/s). Although kinetic symmetry did not improve, kinematic symmetry of both lower extremities did improve in sitting and standing. In total, the subject walked with the device for 2 km. We found the device safe on a single amputee subject in a controlled environment and feasible for future testing on ramps and lower level ambulators.
Exploring Alternative Methods for Simulating Lightning Mechanical Damage Effects on Carbon/Epoxy Laminates
Authors: Lee Juhyeong , Yang Bin , Fu KunKun
Published: February 2023

This study introduces three relatively simple predictive material models simulating lightning mechanical damage effects on carbon/epoxy laminates. The alternative lightning mechanical damage models proposed in this work are (1) the conventional weapons effects program (CONWEP) model, (2) the coupled eulerian-lagrangian (CEL) model, and (3) the smoothed-particle hydrodynamics (SPH) model. These models are developed for 100∼500 kA peak current amplitudes based on total chemical potential energy equivalent to lightning shock wave energy. More specifically, assuming that all lightning shock wave energy is instantaneously converted to chemical potential energy in explosive TNT, two primary factors — an TNT explosive weight and stand-off distance (referring to the distance from the explosion center to the target structure) — are determined to develop CONWEP, CEL, and SPH models. The lightning shock wave model previously published by the authors is considered as a baseline. The predicted dynamic responses (i.e., pressures, displacements, strain rates, and dynamic pressures) and corresponding failure modes are compared with those from the baseline and relevant models available in open literature.
Overall Mechanical Properties of Self-Healing Composites: Effects of Microcapsules Shape, Volume Concentration, Shell Thickness, and Material Properties
Authors: Kazemi Zahra , Azami Mohammad
Published: February 2023

The present work investigates the influence of embedding spherical and spheroidal capsules containing the healing agent within the base polymers to create a self-healing effect on the overall mechanical properties of the entire medium, using numerical and analytical homogenization approaches. The effects of geometrical and mechanical parameters, including capsule shape, the healing agent volume concentration, the capsules shell thickness, and mechanical properties on the overall responses of the self-healing composites are studied. A square-array configuration is assumed for the distribution of the capsules. This idealization enables computing the behavior of such composites computationally via FE analysis and variationally using Hashin-Shtrikman upper bound by taking a unit cell composed of a cube of the matrix with a perfectly bonded capsule at its center. The boundary conditions on the unit cell are applied in a way that the deformation of the unit cell captivates the overall mechanical responses of the entire medium. Our results show a general decrease in the overall properties of the composites, which can be alleviated by increasing the thickness of the capsules shell or using a stiffer shell. Additionally, we show that the geometry of the capsule shell plays a role in reducing the drop in the overall properties of the composite.
Compression Energy Stored in an Additively Manufactured Mesostructure
Authors: Schmitz Anne
Published: February 2023

One facet of sustainable manufacturing is minimizing material usage and waste. This is done by creating latticelike infills for components, i.e. mesostructures. The goal of this study was to quantify the compression energy absorbed by a stereolithographic (SLA) manufactured mesostructure. Fifteen specimens were printed using a Form 2 SLA printer from Formlab. After printing, the specimens were washed in isopropyl alcohol to remove any uncured resin. The specimens were printed as 80 × 80 × 20 mm blocks for compression testing. The structure of the block was a novel, open-source mesostructure designed by Andreas Bastian. The specimens were compressed in a Tinius Olsen compression testing machine. Using Matlab, these compression curves were numerically integrated to obtain energy absorbed as a function of relative displacement. The SLA structures absorbed 0.5–10.9 Joules at 40% relative displacement. As modulus of the base SLA material increased, so did the energy absorbed by the structure (r = 0.867, p < 0.001). This indicates the compression behavior SLA structures may be predicted through modeling to fine tune the structure. This fine tuning could then be used to maximize the energy absorption of the structure for a desired application, e.g. football helmet cushioning.
Simulating a Piezoelectric-Haptic MEMS Actuator in Low-Frequency Vibration
Authors: Benson Alexander , Carl Seth , Duan Shawn
Published: February 2023

When developing a haptic mouse, the authors aimed to exploit a documented phenomenon in which tangential loads to a user’s finger are aliased with positional cues. A flextension-style microelectromechanical system (MEMS) was designed to increase the range of actuation possible with the piezoelectrics preferred by nearly 10. The flextensional system converted the piezoelectric actuator into a two-degree-of-freedom (DOF) system, with the piezoactuator as a cyclic force. The actuator was intended to provide a wide range of feedback, the primary modality being the aliased positional cues with vibration as a secondary feedback mode. A single axis of the complete system was studied and designed for simplicity.

Simulations of a piezoelectric actuator vibrating with and without a human finger resting on the actuator were studied. The actuator resembles a two-DOF system without a finger. With a finger, the actuator becomes a three-DOF system. All systems were simulated using MATLAB’s ODE45 solver.

The quality of a single-degree-of-freedom reduction depended on whether the user’s finger was considered. Without a finger, no significant deviations in the system’s behavior were found; the equivalent spring, mass, and damper coefficients match those calculated by standard reduction methods without complication. The addition of a finger complicated the simulation. The frequency behavior of the single-degree-of-freedom system dropped an order of magnitude below the frequencies of the multi-degree-of-freedom system. This drop resulted in discrepancies between the simulated behavior of the multi-degree-of-freedom and its single-degree-of-freedom equivalent.
Thermo-Mechanical Behavior of Multi-Layer Deposition for Wire Arc Additive Manufacturing of Structural Steel: Wire Arc Additive Manufacturing
Authors: Kumar Amritesh , Bag Swarup , Srivastava V. C. , Amin M. Ruhul
Published: February 2023

Wire arc additive manufacturing (WAAM) process, following the directed energy deposition (DED) technique, has evolved as one of the most prominent additive manufacturing (AM) technologies to fabricate large and intricate shapes of metallic components. The physical basis of the WAAM process is associated with rapid heating, melting, layer-by-layer melt deposition, solidification, and moderate cooling rate of the fabricated part. Consequently, different regions of the additive manufactured part experience variable heating and cooling cycles due to repeated heating and cooling. The continuously varying transient thermal cycles lead to residual stresses and distortion in fabricated components, mainly influenced by the temperature gradient along the build direction. The generation of residual stress and distortion result in warping, delamination, and unfavorable fatigue properties of the AM components. The in-situ prediction of transient temperature profile and its impact on residual stresses in an arc-based DED technique is practically impossible by any contact measurement technologies. As the cooling or idle times between the successively deposited layers play a significant role in the thermomechanical behavior of as-deposited materials, the inclination towards developing a numerical model by considering different process variants in the layer-by-layer deposition process is evolving. In the present work, a finite-element-based thermo-mechanical 3D model is developed for the WAAM process by triggering the effect of the inter-pass cooling period. The model results are validated with experiments reported in independent literature. Increasing the inter-layer dwell time decreases built material’s peak temperature and residual stress. At the same time, the distribution of effective stress along the built material’s center line increases with idle times.
Evaluation of Forward-Facing Child Safety Seat Harness Retainer Clip Position in 35 mph Frontal Barrier Crash Tests
Authors: Bell Lauren , Meyer Steven , Herbst Brian
Published: February 2023

The National Highway Traffic Safety Administration (NHTSA) recommends that children ages 4 to 7 years old should travel in a forward-facing child safety seat (FFCSS) with a harness until reaching the maximum weight or height limit allowed by the car seat manufacturer. There are five types of FFCSS, including convertible, combination, all-in-one, forward-facing only, and integrated (built-in). In the United States, most of the harness systems in FFCSS also include a retainer clip or chest clip; this is a plastic clip that holds the harness shoulder straps together over the child’s chest. NHTSA, National Child Passenger Safety Board (NCPSB), and Safe Kids Worldwide recommend that with the child buckled and the straps tightened snugly, the harness retainer clip should be secured and then positioned at the child’s armpit level. According to NHTSA, the purpose of the clip is as a pre-crash positioner, holding the harness straps together for correct positioning in the event of a crash.[1]

Analysis of child dummies placed in various types of FFCSSs and in various makes and models of vehicles during 35 mph New Car Assessment Program (NCAP) frontal crash tests were used to draw conclusions relative to how the child safety seat was loaded during the collision. Comparison of the position of the clip before, during, and after the crash test was assessed. This additional data was reviewed relative to the University of Michigan Transportation Research Institute (UMTRI) Research Review’s Crash Protection for Child Passengers conclusion that “clips slide down the straps as the child presses forward or may break if sliding is restricted.”[2] Also, for a subset of the crash data collected, direct measurement of the clip displacement was measured. Analysis of this data was used to draw conclusions regarding how much clip movement is typical in a FFCSS when installed in the rear occupant positions of vehicles in a 35 mph frontal barrier crash test.
Experimental Core Flooding Test for Formation Damage During Gel Treatment
Authors: Elsharafi Mahmoud , Green Jesse
Published: February 2023

In mature oil fields, the success of gel treatment results depends on the ability of the gel to reduce the high permeable formation without damaging to low permeable formation. Formation damage refers to the extent of damage reservoir rocks face from various drilling techniques and/or chemical treatment during well completion. A dynamic filtration test was used to investigate this effect using distinct core samples, brine concentrations and preformed particle gels. The effect of high pressures applied on the particle gels on various core samples with various permeability ranges was determined. These gels were pushed into the core holder with samples and the core permeability change was calculated. Different constant pressures were used to push the piston behind the gel samples. Then, the gel was flown around the core sample and collected in the outlet container. Various hardware was used to tighten the apparatus and provide connection between brine source, syringe pump, piston accumulator, core holder, and flow outlet container. The damage on the core was evaluated by comparing the original core permeability and the core permeability after gel treatments. Pressure gauges were used to measure the pressure drop across the core samples. The penetration of the particle gels into the low permeable formations can be decreased by the best selection of gel types, particle sizes, and brine concentrations under the reservoir condition. This work results can be used to select the best gel types for the right reservoir condition such as reservoir permeability, and reservoir pressure.
Assessment of Soccer Ball Inflation Pressurizations and Risk of Brain Injury
Authors: Perkins Richard Allen , Bakhtiarydavijani Amirhamed , Prabhu Raj
Published: February 2023

In this study, we employ a finite element analysis to determine brain injury risks resulting from impacts caused by a soccer ball to the player’s head at various ball inflations. The repetitive ball-head impacts in soccer are a cause for concern considering the literature showing neurodegeneration in soccer pressures. Standard soccer ball inflation pressurizations for a size 5 ball are in-between approximately 60kPa and 110kPa; the effect of these pressurizations on injury risks has not been widely studied. This finite element analysis implements previously validated finite element models of an adult 50th percentile human head and regulation size 5 soccer ball. The results of the simulations are evaluated using existing kinematic injury metrics (HIC15 and BrIC) and peak pressure, Von Mises stress, and maximum principal strain values throughout the brain. The results of our simulations show increasing HIC15, peak pressure, and peak maximum principal strain values for increased ball pressurizations. It is found that increasing the ball pressure increases the rate of energy transfer from the soccer ball to the head, which translates to higher injury metrics and brain stresses and strains. Additionally, the peak contact area between the soccer ball and the head is inversely proportional to the ball pressurizations. Increasing soccer ball inflation pressures can lead to increased brain injury risks due to soccer heading.
Understanding the Expected Deformation of Rectangular Ductwork
Authors: Schaff Cameron , Crispi Matthew , Liu Jane , Peddieson John , Idem Stephen
Published: February 2023

A study was performed to investigate the effects of aspect ratio, material gauge, material properties, joint spacing, loading type and magnitude on the mechanical performance of rectangular ductwork. The SMACNA Industrial Duct Construction Standard (1st and 2nd Editions) rectangular ductwork design standards were reviewed, and theoretical equations contained in the existing literature were identified and evaluated. Allowing for round-off error, the calculations performed in this investigation agreed closely with the SMACNA approach. Finite element predictions of duct deformation were intermediate to the DMI experimental data and those obtained using the SMACNA design procedures, for both 10 gauge and 16 gauge wall thicknesses and twelve load cases.
Non-Linear Analysis of Beam-Reinforced Thin Plates for Modeling Rectangular Duct Systems
Authors: Crispi Matthew , Liu Jane , Peddieson John , Idem Stephen
Published: February 2023

This study introduces a beam-reinforced plate (BRP) finite element model to predict the deformation behavior of a rectangular duct system under positive gauge pressure, and further investigates the existing design procedures employed in practice. A commonly used methodology is to model rectangular duct systems subjected to internal pressure as individual thin plates to predict maximum deflections and set stress limitations. One of the assumptions these existing models are based on is to assume the stiffness of reinforcements is infinite, which obviously is not consistent with the real duct behavior. The proposed BRP model not only accounts for the deformation of the stiffeners, but also the geometric non-linearity of the plates under a uniform internal pressure. By comparing deflection predictions from a whole duct finite element model, it is shown that that the BRP model can predict the deformation behavior accurately under certain circumstances. Parametric studies were performed to understand how geometric variables affect the deflections of duct panels. Therein limitations of the proposed model are discussed and defined. Based on these limitations, further research is recommended to develop plate models that can accurately predict the behavior of complicated duct systems.
Guided Wave Damage Imaging of Composite Laminates With Least-Squares Reverse-Time Migration (LSRTM)
Authors: He Jiaze , Schwarberg Anthony
Published: February 2023

A method for adapting least-squares reverse time migration (LSRTM) for ultrasonic guided wave imaging of composite laminates is proposed in this paper. As composites become more widely used in fields such as the aerospace industry, the need for high resolution imaging in structural health monitoring (SHM) and nondestructive evaluation (NDE) is also growing. For instance, delamination is a common problem in composite laminates, which has led to a certain degree of apprehension in the use of composite materials for load-bearing structures. Although the solver-based imaging techniques using conventional reverse time migration (RTM) methods illuminate damage with a wide range of damage-scattering effects, the resulted images do not fully define the damage regions due to the limited data acquisition aperture, sensor density, frequencies/wavelengths, and incompleteness of adjoint reconstruction. Previously, we have derived the LSRTM theory and benchmarked its high-resolution damage imaging performance for isotropic plates. To improve damage imaging in composite laminates, this paper proposes to create an ultrasonic guided wave-based LSRTM method for anisotropic materials. The derivation of the forward modeling operator and the adjoint operator is presented. Numerical case studies were conducted to show the improvement of LSRTM over RTM in mapping damage in composite plates. Multiple damage sites or damage with a complex shape were created in the numerical studies based on Born approximation-based modeling.
Implementation of ANN Modeling Techniques and Genetic Algorithm in the Diameter Prediction of MWCNTs/Epoxy Nanofibers for CFRP Structures
Authors: Biswas Pias Kumar , Zende Pradnya , Dalir Hamid , Agarwal Mangilal
Published: February 2023

Electrospun multiwalled carbon nanotubes (MWCNTs)/epoxy nanofibers are placed between the layers of standard carbon fiber-reinforced polymer (CFRP) prepreg composites to improve their physical and mechanical properties. As epoxy resin is a thermosetting material, it must be electrospun carefully maintaining a specific viscosity of the epoxy, and optimizing all electrospinning parameters is both costly and time-intensive. Thus, prior to implementing the different experimental techniques, a modeling methodology is an effective tool for regulating the electrospinning process’s contributing factors. In this case, it is observed that having a smaller diameter of MWCNT/epoxy is very critical because MWCNTs stay aligned inside epoxy nanofibers with a smaller diameter than nanofibers with a bigger diameter. Those aligned MWCNTs can lead up to a 29% increase in the flexural strength of a CFRP structure. different Employing artificial neural networks (ANN) models, the present study investigates the effect of key parameters on the fiber diameter and uniformity of electrospun MWCNT/epoxy nanofibers. The goal of this work is to implement and differentiate the multilayer perceptron (MLP) feedforward backpropagation ANN, radial basis function neural network (RBFNN), and very commonly used support vector machine (SVM) methods in order to construct computational models for predicting diameter of MWCNT/epoxy nanofiber with high accuracy.
Acoustic Emission Measurement and Location Analysis of Acoustic Emission Source for Superconducting Coil Quench During Training
Authors: Hirokawa Junko , Nishimura Osamu , Hisakuni Yousuke , Kano Akira , Uehara Hideaki , Monda Tomoko , Hirohata Kenji , Ito Toshinobu , Takami Shohei , Orikasa Tomofumi , Sato Kiyokazu
Published: February 2023

Acoustic emission (AE) measurement is a non-destructive testing method that can detect high-frequency elastic waves generated by mechanical events inside an object, and is able to localize the wave source by using multiple sensors. In order to determine the mechanism causing the quench phenomenon in superconducting coil, we applied the AE method to a small ellipse-shaped coil in a training experiment. Six AE sensors were installed on the coil surface before the coil was cooled to 4 K in a vacuum vessel and excited. The current to the coil was controlled to produce a gradual increase until the quench occurred. The entire training experiment ended after over 10 quenches and all AE events that occurred in each training cycle were measured. The location of the AE source inside the coil was calculated from the difference in arrival time between sensors, and the results were plotted on an expansion plan of the coil. High-amplitude AE events appeared in areas assumed to have sufficiently high internal stress to cause concentration of strain energy.