bluuebunny/crossref_metadata_2025 huggingface dataset:
Treating melasma with the 1064 nm Nd:YAG laser with a 650‐microsecond pulse duration: A clinical evaluation
Authors: Greywal Tanya , Ortiz Arisa
Published: November 2021

Background

The effective treatment of melasma remains a challenge that necessitates a multifaceted approach that includes strict sun protection, bleaching creams, chemical peels, and laser therapy. The 1064 nm Nd:YAG laser with a 650‐microsecond pulse duration provides a safe option for all skin types.

Methods

We treated 10 patients with the 1064 nm Nd:YAG laser with a 650‐microsecond pulse duration. Treatments were performed every 2–4 weeks.

Results

Using a conservative treatment protocol, lightening of melasma occurred as early as 3 weeks post‐treatment, with all subjects requiring several treatment sessions to achieve adequate resolution of their melasma. The majority of subjects experienced up to 25% improvement after two treatments, and an even more noticeable improvement after the 3rd treatment session. None reported any associated pain or discomfort.

Conclusions

Advantages of this laser modality include essentially no pain or downtime, lower risk of rebound, and the ability to safely treat all skin types with melasma. Therefore, the 1064 nm Nd:YAG laser with a 650‐microsecond pulse duration serves as a treatment option for melasma.
Self‐care behaviours and related cultural factors among Chinese immigrants with cardiovascular disease in western countries: an integrative review
Authors: Zeng Ling , Perry Lin , Xu Xiaoyue
Published: November 2021

Aims and objectives

This review aimed to demonstrate the self‐care behaviours of first‐generation Chinese immigrants with cardiovascular disease in western countries and identify related cultural factors.

Background

Self‐care is the cornerstone to mitigate disease symptoms and maintain health status. Chinese immigrants to western countries, operating within a cross‐cultural context, may find self‐care to manage their cardiovascular disease challenging.

Design

An integrative review was conducted.

Methods

Seven databases were searched Scopus, ProQuest Health & Medicine, Medline (Ovid), Embase (Ovid), AMED (Ovid), PsycINFO and CINAHL, with output limited to peer‐reviewed studies published from 2000 to 2020 in English or Chinese. Initially, 2037 papers were screened. Six papers were retained and critiqued using the Joanna Briggs Institute critical appraisal tools. Deductive and inductive approaches were utilised to analyse the findings. The PRISMA 2020 checklist informed review reportage.

Result

In general, Chinese immigrants with cardiovascular disease took an active role in management of their cardiovascular disease, including through diet and activity adaptation and adherence to western medication. Families also played a significant role in disease decision‐making and management. However, language and cultural barriers impeded their access to health information and resources in host countries.

Relevance to clinical practice

Understanding self‐care behaviours and associated cultural factors among Chinese immigrants with cardiovascular disease is important to improve nurses’ culturally sensitive practices and provide tailored health education interventions to promote self‐care behaviours among immigrant populations. The scarcity of literature on self‐care behaviours among Chinese first‐generation immigrants with cardiovascular disease indicates the need for further research in this area. Development of culturally and linguistically sensitive health resources and education programs is urgently needed.
Participation in a time of climate crisis
Authors: ARMENI CHIARA , LEE MARIA
Published: November 2021

The climate crisis puts real pressure on legal guarantees of public participation in decision making. This pressure comes from a number of directions, but we are particularly concerned with the technocratic erosion of routines of participation, in a turn to expertise rather than democracy for legitimate decision making. At the same time, populists resist the constraints imposed on their power by legal rights of participation. We argue, however, that the climate crisis, while putting pressure on participation, also reinforces its necessity, and the limitations of technocratic decision making. Politics is unavoidable, even and especially in a crisis. Law, or its silence, contributes to the context, the place, and the meaning of participation, and we study its strangely underexplored role in shaping participation on the ground.
Anterior decompression of persistent vertebral artery occlusion caused by the cervical facet joint originated osteophyte
Authors: Ren Yilong , Chen Huairui , Zhang Chi , Xie Ning
Published: November 2021

Background

Persistent vertebral artery occlusion caused by compression of cervical facet joint originated osteophyte is exceptional rare. The authors sought to achieve adequate decompression of the vertebral artery (VA) with less stability decrease and movement restriction via the anterior approach, and to the authors' knowledge, no case of anterior decompression of this condition has been reported, and combination of intraoperative indocyanine green (ICG) angiography in the setting of VA decompression is also rare.

Case presentation

A 77‐year‐old man presented continuous vertigo, unsteady gait and dysphagia with no relationship to the head movement. Preoperative computed tomography angiography (CTA) and digital substraction angiography (DSA) examination revealed the left vertebral artery was severely compressed at C4‐5 level with approximately 95% occlusion due to a left C4‐5 facet joint originated large osteophyte. Successful anterior decompression was performed without fusion and intraoperative ICG fluorescence angiography proved excellent blood flow. After surgery, vertebrobasilar insufficiency symptoms remarkably improved with no neurological deficits and no recurrence at 12 months' follow‐up.

Conclusions

The authors' therapeutic strategy of anterior decompression was successful in treating VA compression due to facet joint overgrowth with adequate exposure, no stability decrease and movement restriction, and lower rates of neck pain and blood loss.
Role of aripiprazole in the management of behavioural and psychological symptoms of dementia: a narrative review
Authors: Álvarez‐Fernández Baldomero , Bernal‐López M. Rosa , Gómez‐Huelgas Ricardo
Published: November 2021

Behavioural and psychological symptoms of dementia affect in a great way quality of life of both patients and their caregivers, which increases the risk of patient institutionalisation when such symptoms are poorly controlled. One of the drugs that are used for controlling behavioural and psychological symptoms of dementia (BPSD) is aripiprazole. This narrative review aims to solve three basic questions. Is aripiprazole useful for the management of these symptoms? Does aripiprazole play a substantial role regarding safety and efficacy, compared with the other pharmacological options available for the same purpose? Has aripiprazole gained importance in treatment regimens of these symptoms, in current clinical practice? We conclude that aripiprazole is effective to manage BPSD. Moreover, it has shown a good safety profile compared with other antipsychotics in advanced disease and frail patients. Thus, aripiprazole has gained importance in current management algorithms for dementia patients mainly due to its efficacy regarding rapid control of agitation and aggressiveness.
Exposure to intimate partner aggression during childhood is associated with blunted skin conductance recovery following stress in early adulthood
Authors: Rawn Kyle P. , Keller Peggy S.
Published: November 2021

This study examines skin conductance level (SCL) trajectories and childhood exposure to intimate partner aggression (IPA) committed between parents in a sample of college students. Although IPA among parents does not directly involve children, children frequently see or are exposed to IPA first‐hand when it occurs. This exposure to IPA increases risks for psychopathology and emotional or behavioral difficulties for children or adolescents later in life. However, research has not yet examined the stress response patterns of individuals exposed to IPA, nor how reactivity to stress may be altered based on this exposure. Participants included 161 college students who completed questionnaires assessing demographics, mental health, and exposure to IPA, and also reported on family functioning and parental drinking habits. Additionally, participants completed a three‐minute mirror tracing task followed by a three‐minute recovery period while SCL was monitored. Multilevel modeling was used to assess whether frequency or level of exposure to IPA was related to trajectories of SCL. Neither variable was related to SCL trajectories during the mirror‐tracing task. However, both frequency and level of exposure were related to SCL trajectories during the recovery period, such that for participants reporting higher levels of either IPA exposure variable, SCL trajectories during recovery declined less rapidly and did not decline to as low of a level compared to participants reporting lower levels of IPA exposure. This blunted SCL recovery may be due to wear and tear from repeated innervation, or a calibrating of the SCL response to adapt to a volatile home environment.
Adolescents’ perioperative experiences in relation to inpatient and outpatient elective surgery – a qualitative study
Authors: Pestana‐Santos Marcia , Pestana‐Santos Adriana , Santos Margarida Reis , Lomba Lurdes
Published: November 2021

Background

Perioperative experience can be very distressing in adolescence if not managed properly by healthcare professionals. In the clinical context, the emotional expression of the adolescent is less spontaneous, which makes the assessment of anxiety, pain or even the desire to be involved in the perioperative process, difficult. Listening to their perioperative experiences will permit an understanding of their difficulties and expectations, regardless of the surgical intervention undergone.

Aim

To explore the adolescents’ perioperative experiences in relation to inpatient and outpatient elective surgery.

Methods

Qualitative exploratory study, with thematic analysis approach. A purposive sample of 40 adolescents aged 14–18 years and in the perioperative period, from two paediatric surgery settings in a university hospital, was questioned from January to July 2020. Data were collected using a semi‐structured interview and analysed inductively with qualitative thematic analysis.

Results

The data yielded one major theme, five themes, and 14 sub‐themes. The major theme, Adolescent in perioperative period, included the five themes: (1) emotional and psychological aspects; (2) physical aspects; (3) social aspects; (4) organizational aspects; (5) previous surgical experience. Adolescents expressed fear of the unknown, anxiety, difficulty in pain control, and feelings of autonomy loss. Issues related to withdrawal from school and friends is also a focus of adolescent concern during the perioperative period. Despite showing satisfaction with the way they were cared for, they complained about the lack of pre‐ and post‐operative preparation.

Conclusion

There are aspects that should be considered when caring for adolescents in perioperative period. As far as possible, programmes to prevent adolescents’ anxiety in perioperative period should be designed in a holistic perspective, with aim at the psychological, physical, sociocultural, and organisational aspects.
An Assessment of Third‐Party Reporting of Close Ties to Measure Sensitive Behaviors: The Confidante Method to Measure Abortion Incidence in Ethiopia and Uganda
Authors: Giorgio Margaret , Sully Elizabeth , Chiu Doris W.
Published: November 2021

Indirect estimation techniques are important tools for measuring sensitive and stigmatized behaviors. This includes third‐party reporting methods, which have become increasingly common in the field of abortion measurement, where direct survey approaches notoriously lead to underreporting. This paper provides the first in‐depth assessment of one of the most widely used of these techniques in the field of abortion measurement: the confidante method. We outline six key assumptions behind the confidante method and describe how violations of these assumptions can bias resulting estimates. Using data from modules added to the performance monitoring for action surveys in Uganda and Ethiopia in 2018, we compute one‐year abortion incidence estimates using the confidante method. We also perform a validation check, using the method to estimate intrauterine device /implant use. Our results revealed implementation problems in both settings. Several of the method's foundational assumptions were violated, and efforts to adjust for these violations either failed or only partially addressed the resulting bias. Our validation check also failed, resulting in a gross overestimate of intrauterine device/implant use. These results have implications more broadly for the potential biases that can be introduced in using third‐party reporting of close ties to measure other sensitive or stigmatized behaviors.
“Easy” and “hard” issues: Attitude extremity and a role of the need to evaluate
Authors: Lee Heysung
Published: November 2021

Background

This article addresses the topic of issue polarization among the mass public, focusing on the classic typology of “easy” and “hard” issues (Carmines and Stimson, 1980) and the influence of the individual‐level motivational variable, which is the need to evaluate.

Objective

Carmines and Stimson (1980) suggest that issues are characterized by their “hardness,” the degree of how much issues are easy to understand and make political evaluations. This article contends that the NTE would positively relate to attitude extremity of “hard” issues, which require extensive motivations for political judgment but would not necessarily be associated with attitude extremity of “easy” issues, which do not require such motivations.

Methods

In the analyses, four “easy” issues (abortion, same‐sex marriage, affirmative action, and gun control) and four “hard” issues (immigration, tax, health care, and climate change) were selected to compare the effects of the NTE on attitude extremity, based on previous literature. The data of 2016 American National Election Survey was used to test the hypotheses.

Results

The analyses using the data of the 2016 American National Election Survey supported the hypotheses by showing that the need to evaluate was related to increased attitude extremity on all “hard” issues, whereas need to evaluate was not associated with extremity on “easy” issues except the issue of affirmative action.

Conclusion

Need to evaluate is related to attitude extremity on “easy” and “hard” issues.
Has Williamson's Claim that Knowledge Is the most General Factive Mental State Been Disproved?
Authors: Ask Zaar Balder Edmund
Published: November 2021

In this paper, I evaluate some recent attacks on Williamson's claim that knowledge is the most general factive stative propositional attitude. Two types of approaches are discussed: The first approach attempts to show that there are factive mental states denoted by factive mental state operators that are not cases of knowing. The second approach aims to show that there are factive mental states that to Williamson count as cases of knowing, but nonetheless fail to entail a corresponding belief. If either of these approaches were successful, it would potentially be damaging for Williamson's theory of knowledge. I argue that recent arguments that exemplify these approaches are unconvincing.
Recovery of platelet‐rich red blood cells and acquisition of convalescent plasma with a novel gravity‐driven blood separation device
Authors: Osemwengie Dion , Lagerberg Johan W. , Vlaar Richard , Gouwerok Erik , Go Mya , Nierich Arno P. , de Korte Dirk
Published: November 2021

Objectives

Our objectives were to determine the separation characteristics and blood product quality of a gravity‐driven microfiltration blood separation system (HemoClear, The Netherlands).

Background

A range of centrifugal blood separation devices, including intraoperative cell salvage devices (cell savers) and apheresis machines, are available to assist in preparing both allogenic and autologous blood products. These devices are expensive to operate and require extensive training.

Methods and Materials

Nine whole blood units were collected under standard conditions and analysed for haematological parameters, thromboelastographic properties, platelet morphology and activation, and red blood cell (RBC) deformability and morphology. Three whole blood units were separated by means of the HemoClear device, into a liquid and cellular component. The cellular component was diluted with SAGM and cold stored for 14 days. To simulate cell salvage six whole blood units were diluted with isotonic saline, followed by multiple HemoClear separation rounds.

Results

The recovery of both RBCs (100 ± 1.6%) and white blood cells (99 ± 4.5%) after undiluted filtration were very high, while platelet recovery was high (83 ± 3.0%). During the filtration, and cold storage after filtration storage both the non‐deformable RBC fraction and the RBC maximum elongation remained stable. Parameters of thromboelastography indicated that platelets remain functional after filtration and after 7 days of cold storage. In the cell salvage simulation the total protein load in the cellular fraction was reduced by 65 ± 4.1% after one washing round and 84 ± 1.9% after two consecutive washing rounds.

Conclusion

The novel blood filter studied effectively separates whole blood into diluted plasma and platelet‐rich RBCs. Moreover, the device effectively washed diluted whole blood, driving over 80% of proteins to the liquid component.
Development of a preoperative risk score predicting allogeneic red blood cell transfusion in children undergoing spinal fusion
Authors: Eisler Lisa , Chihuri Stanford , Lenke Lawrence G. , Sun Lena S. , Faraoni David , Li Guohua
Published: November 2021

Background

Children undergoing spinal fusion often receive blood products. The goal of this study was to develop a preoperative score to help physicians identify those who are at risk of allogeneic red blood cell (RBC) transfusion.

Study design and methods

This retrospective study of children undergoing spinal fusion in the ACS‐NSQIP Pediatric database (2016–2019) aimed at identifying risk factors associated with allogeneic RBC transfusion. Univariable logistic regression and multivariable logistic regression were performed using preoperative patient characteristics and aided in the creation of a simplified scoring system.

Results

Out of 13,929 total patients, 2990 (21.5%) were transfused. We created a risk score based on 10 independent predictors of transfusion: age, sex, race, weight < 3rd percentile, American Society of Anesthesiologists physical status classification, cardiac risk factors, hematologic disease, preoperative anemia, deformity type, and number of spinal levels to be fused. Patients in both the training and testing cohorts were assigned a score ranging from 0 (lowest risk) to 21 (highest risk). The developed transfusion risk score showed 77% accuracy in distinguishing patients who did not receive a transfusion during or soon after surgery (AUROC 0.7736 [95% CI, 0.7619–0.7852]) in the training cohort and 77% accuracy (AUROC 0.7732 [95% CI, 0.7554–0.7910]) in the testing cohort.

Discussion

Our score, based on routinely available preoperative data, accurately estimates the risk of allogeneic RBC transfusion in pediatric patients undergoing spinal fusion. Future studies will inform whether patient blood management interventions targeted to high‐risk patients can help reduce the need for transfusion and improve outcomes.
Donor citrate reactions influence the phenotype of apheresis platelets following storage
Authors: van der Wal Dianne E. , Davis April M. , Marks Denese C.
Published: November 2021

Background

Platelet collection and processing methods, as well as donor attributes, can influence platelet function and quality during ex vivo storage. In this study, activation and procoagulant responses in platelets collected from donors experiencing a citrate reaction (CR) were investigated.

Study design and methods

Apheresis platelet components (n = 54) were stored in 100% autologous plasma and tested on days 1 and 5 post‐collection. Platelet components were categorized into two groups according to whether the donor had experienced a CR during donation (n = 10; non‐CR group, n = 44). Platelet aggregation was initiated with collagen and thrombin. Platelet phenotype was characterized by flow cytometry. Fibrinogen binding was assessed following collagen + thrombin stimulation (COATed platelets), and procoagulant activity was assessed using a procoagulant phospholipid assay (PPL). Platelet microparticle (PMP) subsets were enumerated by flow cytometry.

Results

Basal von Willebrand factor (VWF) binding was higher in the CR donations when compared with the non‐CR group. Collagen aggregation was significantly higher in platelets from CR donations, in contrast to aggregation induced by thrombin. The proportion of phosphatidylserine (PS) positive PMP and PPL clotting time were higher in the CR group, in contrast to the number of basal PS+ platelets and COATed platelets following stimulation.

Conclusion

Platelets donated by donors who experienced a CR during donation had higher platelet activation response and possibly a more procoagulant PMP phenotype, suggesting that this donor reaction might lead to increased platelet activation.
Severe acute hypoxia impairs recovery of voluntary muscle activation after sustained submaximal elbow flexion
Authors: McKeown Daniel J. , McNeil Chris J. , Brotherton Emily J. , Simmonds Michael J. , Kavanagh Justin J.
Published: November 2021

The purpose of this study was to determine how severe acute hypoxia alters neural mechanisms during, and following, a sustained fatiguing contraction. Fifteen participants (25 ± 3.2 years, six female) were exposed to a sham condition and a hypoxia condition where they performed a 10 min elbow flexor contraction at 20% of maximal torque. For hypoxia, peripheral blood oxygen saturation () was titrated to 80% over a 15 min period and maintained for 2 h. Maximal voluntary contraction torque, EMG root mean square, voluntary activation, rating of perceived muscle fatigue, and corticospinal excitability (motor‐evoked potential) and inhibition (silent period duration) were then assessed before, during and for 6 min after the fatiguing contraction. No hypoxia‐related effects were identified for neuromuscular variables during the fatigue task. However, for recovery, voluntary activation assessed by motor point stimulation of biceps brachii was lower for hypoxia than sham at 4 min (sham: 89% ± 7%; hypoxia: 80% ± 12%; P = 0.023) and 6 min (sham: 90% ± 7%; hypoxia: 78% ± 11%; P = 0.040). Similarly, voluntary activation (P = 0.01) and motor‐evoked potential area (P = 0.002) in response to transcranial magnetic stimulation of the motor cortex were 10% and 11% lower during recovery for hypoxia compared to sham, respectively. Although an of 80% did not affect neural activity during the fatiguing task, motor cortical output and corticospinal excitability were reduced during recovery in the hypoxic environment. This was probably due to hypoxia‐related mechanisms involving supraspinal motor circuits.

image

Key points

Acute hypoxia has been shown to impair voluntary activation of muscle and alter the excitability of the corticospinal motor pathway during exercise.

However, little is known about how hypoxia alters the recovery of the motor system after performing fatiguing exercise.

Here we assessed hypoxia‐related responses of motor pathways both during active contractions and during recovery from active contractions, with transcranial magnetic stimulation and motor point stimulation of the biceps brachii.

Fatiguing exercise caused reductions in voluntary activation, which was exacerbated during recovery from a 10 min sustained elbow flexion in a hypoxic environment.

These results suggest that reductions in blood oxygen concentration impair the ability of motor pathways in the CNS to recover from fatiguing exercise, which is probably due to hypoxia‐induced mechanisms that reduce output from the motor cortex.
Lactate ions induce synaptic plasticity to enhance output from the central respiratory network
Authors: Bueschke Nikolaus , Amaral‐Silva Lara , Hu Min , Santin Joseph M.
Published: November 2021

Lactate ion sensing has emerged as a process that regulates ventilation during metabolic challenges. Most work has focused on peripheral sensing of lactate for the control of breathing. However, lactate also rises in the central nervous system (CNS) during disturbances to blood gas homeostasis and exercise. Using an amphibian model, we recently showed that lactate ions, independently of pH and pyruvate metabolism, act directly in the brainstem to increase respiratory‐related motor outflow. This response had a long washout time and corresponded with potentiated excitatory synaptic strength of respiratory motoneurons. Thus, we tested the hypothesis that lactate ions enhance respiratory output using cellular mechanisms associated with long‐term synaptic plasticity within motoneurons. In this study, we confirm that 2 mM sodium lactate, but not sodium pyruvate, increases respiratory motor output in brainstem‐spinal cord preparations, persisting for 2 h upon the removal of lactate. Lactate also led to prolonged increases in the amplitude of AMPA‐glutamate receptor (AMPAR) currents in individual motoneurons from brainstem slices. Both motor facilitation and AMPAR potentiation by lactate required classic effectors of synaptic plasticity, L‐type Ca2+ channels and NMDA receptors, as part of the transduction process but did not correspond with increased expression of immediate‐early genes often associated with activity‐dependent neuronal plasticity. Altogether these results show that lactate ions enhance respiratory motor output by inducing conserved mechanisms of synaptic plasticity and suggest a new mechanism that may contribute to coupling ventilation to metabolic demands in vertebrates.

Key points

Lactate ions, independently of pH and metabolism, induce long‐term increases in respiratory‐related motor outflow in American bullfrogs.

Lactate triggers a persistent increase in strength of AMPA‐glutamatergic synapses onto respiratory motor neurons.

Long‐term plasticity of motor output and synaptic strength by lactate involves L‐type Ca2+ channels and NMDA‐receptors as part of the transduction process.

Enhanced AMPA receptor function in response to lactate in the intact network is causal for motor plasticity.

In sum, well‐conserved synaptic plasticity mechanisms couple the brainstem lactate ion concentration to respiratory motor drive in vertebrates.
Olivocochlear projections contribute to superior intensity coding in cochlear nucleus small cells
Authors: Hockley Adam , Wu Calvin , Shore Susan E.
Published: November 2021

Understanding communication signals, especially in noisy environments, is crucial to social interactions. Yet, as we age, acoustic signals can be disrupted by cochlear damage and the subsequent auditory nerve fibre degeneration. The most vulnerable medium‐ and high‐threshold‐auditory nerve fibres innervate various cell types in the cochlear nucleus, among which the small cells are unique in receiving this input exclusively. Furthermore, small cells project to medial olivocochlear (MOC) neurons, which in turn send branched collaterals back into the small cell cap. Here, we use single‐unit recordings to characterise small cell firing characteristics and demonstrate superior intensity coding in this cell class. We show converse effects when activating/blocking the MOC system, demonstrating that small‐cell unique coding properties are facilitated by direct cholinergic input from the MOC system. Small cells also maintain tone‐level coding in the presence of background noise. Finally, small cells precisely code low‐frequency modulation more accurately than other ventral cochlear nucleus cell types, demonstrating accurate envelope coding that may be important for vocalisation processing. These results highlight the small cell olivocochlear circuit as a key player in signal processing in noisy environments, which may be selectively degraded in ageing or after noise insult.

Key points

Cochlear nucleus small cells receive input from low/medium spontaneous rate auditory nerve fibres and medial olivocochlear neurons.

Electrical stimulation of medial olivocochlear neurons in the ventral nucleus of the trapezoid body and blocking cholinergic input to small cells using atropine demonstrates an excitatory cholinergic input to small cells, which increases responses to suprathreshold sound.

Unique inputs to small cells produce superior sound intensity coding.

This coding of intensity is preserved in the presence of background noise, an effect exclusive to this cell type in the cochlear nucleus.

These results suggest that small cells serve an essential function in the ascending auditory system, which may be relevant to disorders such as hidden hearing loss.
Sensors in Autonomous Vehicles: A Survey
Authors: Ayala Rodrigo , Mohd Tauheed Khan
Published: November 2021

Research and technology in autonomous vehicles is beginning to become well recognized among computer scientists and engineers. Autonomous vehicles contain a combination of global positioning system (GPS), light detection and ranging (LIDAR), cameras, radio detection and ranging (RADAR), and ultrasonic sensors (which are hardly ever included). These autonomous vehicles use no less than two sensing modalities and usually have three or more. The goal of this research is to determine which sensor to use depending on the functionality of the autonomous vehicle and analyze the similarities and differences of sensor configurations (which may come from different industries too). This study summarizes sensors in four industries: personal vehicles, public transportation, smart farming, and logistics. In addition, the paper includes advantages and disadvantages of how each sensor configuration are helpful by taking into consideration the activity that has to be achieved in the autonomous vehicle. A table of results is incorporated to organize most of the sensors’ availability in the market and their advantages and disadvantages. After comparing each sensor configuration, recommendations are going to be proposed for different scenarios in which some types of sensors will be more useful than others.
Free Vibrations of Composite Shallow Circular Cylindrical Shell Panels With a Bonded Central Stiffening Shell Strip
Authors: Yuceoglu U. , Özerciyes V.
Published: November 2021

This study is concerned with the “Free Vibrations of Composite Shallow Circular Cylindrical Shells or Shell Panels with a Central Stiffening Shell Strip”. The upper and lower shell elements of the stiffened composite system are considered as dissimilar, orthotropic shallow shells. The upper relatively narrow stiffening shell strip is centrally located and adhesively bonded to the lower main shell element In the theoretical formulation, a “First Order Shear Deformation Shell Theory (FSDST)” is employed. The complete set of the shallow shell dynamic equations (including the stress resultant-displacement and the constitutive equations) and the equations of the thin flexible, adhesive layer are first reduced to a set of first order system of ordinary differential equations. This final set forms the governing equations of the problem. Then, they are integrated by means of the “Modified Transfer Matrix Method”. In the adhesive layer, the “hard” and the “soft” adhesive effects are considered. It was found that the material characteristics of the adhesive layer influence the mode shapes and the corresponding natural frequencies of the composite shallow shell panel system. Additionally, some parametric studies on the natural frequencies are presented.
Piezoelectric Actuation for Smart Sandwich Structures: Closed Form Solutions
Authors: Abramovich H.
Published: November 2021

A new piezoelectric actuation mechanism for smart sandwich structures is investigated and its performances are compared with the traditional one, which is based on an induced bending moment This piezoelectric mechanism deals with inducing shear forces and it is the result of piezoelectric materials, which are constrained and poled perpendicular to the applied electric field direction (across the thickness).

The three-coupled equations of motion of a general non-symmetric piezolaminated composite beam subjected to axial and lateral tractions with the new actuation mechanism are derived. The displacement field is based on a first order shear deformation theory. The static case is investigated for continuous piezoelectric layers and for piezoelectric patches embedded into the carrying beam. Closed form solutions for the bending angle and the axial and lateral displacements along the beam are presented for various configurations of lay-up, boundary conditions and lateral tractions.
Dynamic Fracture Toughness of a Unidirectional Graphite/Epoxy Composite
Authors: Liu C. , Rosakis A. J. , Stout M. G.
Published: November 2021

In this investigation, we studied the process of dynamic crack propagation in a fiber-reinforced composite material using the optical Coherent Gradient Sensing (CGS) technique combined with high-speed photography. The mode-I fracture toughness of the unidirectional graphite/epoxy composite, IM7/8551-7, as a function of the crack-tip speed, was measured quantitatively. It was found that up to the Rayleigh wave speed of the composite material, the mode-I fracture toughness is a decreasing function of the crack-tip velocity. This behavior is similar to that observed in the dynamic crack propagation along interfaces between two homogeneous solids.
On the Prediction of Damping in Composite and Sandwich Structures
Authors: Birman Victor , Byrd Larry W.
Published: November 2021

The paper outlines two methodologies for the analytical evaluation of the loss factor in composite laminates and in sandwich structures. One of these methods is based on the analysis of free vibrations, while the second approach utilizes mechanics of materials. The loss factor can be predicted both for specially orthotropic as well as for generally orthotropic laminae, subjected to axial stresses and/or transverse shear. The results for the loss factor of the laminae are in good agreement with available experimental data. As follows from numerical examples, the loss factor of polymer-matrix composites increases with the lamination angle and experiences relatively small variations at large values of these angles.
Interactive Buckling of Sandwich Plates Under Compression
Authors: Sridharan Srinivasan , Sunjung Kim , El-Sayed Sami I.
Published: November 2021

Compressive behavior of two classes of “sandwich” structures is investigated. These structures have for their principal load bearing components two relatively stiff parallel horizontal sheets which are interconnected in one of the following ways: (i) by a highly compliant core material such as foam, or (ii) a set of discrete stiffeners connecting the parallel (top and bottom) sheets. In case (i), the structure can buckle in either a local mode in which the core and the facing bend together or a wrinkling mode in which the facing sheet undergoes severe bending with the core subjected to deformation in the transverse plane. It is found that these plates have neither post buckling stiffness nor do they exhibit any imperfection-sensitivity. In case (ii) the point of principal interest is the interaction of local and overall buckling. For the case of coincident local and overall buckling, it is found that 30% reduction in the maximum load can occur for modest levels of imperfections as a result of modal interaction.
See Labs Run: A Design-Oriented Laboratory for Teaching Dynamic Systems
Authors: Cham Jorge G. , Stafford Brandon , Cutkosky Mark R.
Published: November 2021

Design engineers must have an intuitive understanding of the behavior of dynamic systems. Teaching the mathematical tools for analyzing and designing dynamic systems presents the challenge of maintaining the connection to the physical world. This paper describes a novel sequence of undergraduate laboratory experiments that illustrates basic concepts in dynamic system analysis and motivates their use as design tools. The approach taken connects the laboratory sessions with a design goal for a dynamic mechanical device that the students can see, touch, re-design and modify. The device used is called the “Dashpod,” a simple, pneumatically-actuated, self-stabilizing, dynamic hopping machine. Through coordinated laboratory sessions and lectures, students used classroom concepts to improve the machine’s hopping motion. This paper describes the purpose and design of the Dashpod, presents examples of how it was integrated into laboratory exercises and shows results of student evaluations.
Abutment Hammering Tool for Dental Implants
Authors: O’Callaghan John , Birichi Robert , Goddard Timothy , Jagodnik John , Westbrock Sean
Published: November 2021

One method for installing dental prosthetics uses components fastened with a tapered interference fit. An abutment is fastened into an implant to provide an anchor for the prosthesis. The current method of installation involves hammering with a dental mallet, which provides inconsistent force. A proposal to replace this method is presented. The mechanics of the taper lock were examined to determine the optimal seating force. The chosen design was analyzed for potential weaknesses. A proof of concept prototype was fabricated and a prototype is being manufactured for further analysis. Experimentation indicates that the variance of applied force is significantly reduced.
Design of a Mobility Mechanism for a Rescue and Surveillance Vehicle
Authors: Shah Amip J. , Resciniti Michael L.
Published: November 2021

Even though there may not be any survivors, rescue workers routinely risk their own lives in the hope of saving victims of accidents or natural disasters. However, inaccessibility to the disaster site often delays rescue efforts, thereby reducing the chances of survival. Students at Rowan University have proposed the construction of a rescue and surveillance vehicle (RSV) — a remote-controlled, mobile system designed to provide rescuers with means of finding survivors without having to needlessly risk their own lives. This paper describes the overall concept behind the RSV while focusing on the design and construction of a mobility mechanism to provide universal navigability.
Bumpless Build-Up Layer Packaging
Authors: Towle Steven N. , Braunisch Henning , Hu Chuan , Emery Richard D. , Vandentop Gilroy J.
Published: November 2021

Bumpless Build-Up Layer (BBUL) is a novel package developed to meet future packaging technology requirements. The BBUL package provides the advantages of small electrical loop inductance and reduced thermomechanical stresses on low dielectric constant (low-k) die materials. Furthermore, it allows for high lead count, ready integration of multiple electronic and optical components [such as logic, memory, radio frequency, microelectromechanical systems (MEMS), among others], and inherent scalability. In the present paper we investigate and discuss some of the process, routing, electrical, thermal, and mechanical attributes of BBUL.
Experimental Determination of the Forced-Convection Gas-to-Wall Heat Transfer Coefficient in a Packed Bed for High Temperature Thermal Energy Storage
Authors: Nsofor Emmanuel C. , Adebiyi George A.
Published: November 2021

Measurements of the gas-to-wall forced convection heat transfer coefficient in a packed bed, high-temperature, thermal energy storage system were carried out. The maximum temperature attained was 1000°C. Effects of media property variations with temperature were incorporated along with detailed uncertainty analysis. Results were correlated in terms of Nusselt number, Prandtl number and Reynolds number. The operating fluid during energy storage was flue gas and air during recovery, making this more applicable to industrial waste recovery and similar systems. Similar studies used air for both storage and recovery and developed correlations from experiments at either room temperature or slightly above. Few associated results with corresponding uncertainty margins. Due to substantial uncertainties associated with the measurements of this heat transfer coefficient, it is significant to note that no firm conclusions can be reached on the validity or otherwise of existing similar correlations for which the uncertainty margins were not reported.
Modeling of Transient Two-Phase Liquid-Liquid Flow in Pipelines
Authors: Núñez-Solís R. , Fairuzov Yuri V.
Published: November 2021

A study of transient oil-water flow in hilly-terrain pipelines is described in the present paper. Numerical simulation of terrain slug propagation during the line startup is performed using a novel computer code, mFLOW, for modeling transient flow of two immiscible liquids in pipelines. It is shown that a startup slug may propagate through the system without deformation of its front and tail or may dissipate. The mechanisms of slug dissipation are discussed. It is shown that the fluid pressure response is governed mainly by the process of water holdup wave propagation. It is demonstrated that the analysis of fluid transients in pipelines conveying oil-water mixtures provides useful information for the evaluation of the risk of over-pressurization during the startup period.
Characterization of Visually Detected Coherent Motions in the Turbulent Boundary Layer
Authors: Hirschi Christopher Robin
Published: November 2021

Research over the past 40 years indicates that coherent motions within the turbulent boundary layer account for disproportionate contributions to momentum transport (Robinson, 1991). To better understand these motions, low-Reynolds number turbulent boundary layer experiments were conducted to investigate the instantaneous velocity and vorticity fields associated with near-wall coherent motion interactions. The present study identifies and explores the most prevalent flow characteristics associated with the vertical transport of injected passive marker from the viscous sublayer.
Experimental and Numerical Hydrodynamic Modeling of an Underwater Manipulator
Authors: Khanicheh A. , Tehranian A. , Meghdari A. , Sadeghipour M. S.
Published: November 2021

This paper presents the kinematics and dynamic modeling of a three-link (3-DOF) underwater manipulator where the effects of hydrodynamic forces are investigated. In our investigation, drag and added mass coefficients are not considered as constants. In contrast, the drag coefficient is a variable with respect to all relative parameters. Experiments were conducted to validate the hydrodynamic model for a one degree-of-freedom manipulator up to a three degrees-of-freedom manipulator. Finally, the numerical and experimental results are compared and thoroughly discussed.
Parallel, Multi-Zone, Multi-Block Solver to Study Arterial Branches in Human Vascular System
Authors: Tadjfar M. , Himeno R.
Published: November 2021

The unsteady, three-dimensional, incompressible Navier-Stokes equations are solved numerically to study arterial branches in human vascular system. The solver is capable of dealing with moving boundaries and moving grids. It is designed to handle complex, three-dimensional vascular systems. The computational domain is divided into multiple block subdomains. At each cross section the plane is divided into twelve sub-zones to allow flexibility for handling complex geometries and, if needed, appropriate parallel data partitioning. A second-order in time and third-order upwind finite volume method for solving time-accurate incompressible flows based on pseudo-compressibility and dual time-stepping technique is used. For parallel execution, the flow domain is partitioned. Communication between the subdomains of the flow on Riken’s VPP/700E supercomputer is implemented using MPI message-passing library. The code is capable of running on both shared and/or distributed memory architectures.
Instability and Heat Transfer in Mixed Convection Flow in a Horizontal Duct With Discrete Heat Sources
Authors: Wang Qinghua , Jaluria Yogesh
Published: November 2021

Three dimensional mixed convection flow in a horizontal rectangular duct at low Reynolds numbers 5 ≤ Re ≤ 100 has been investigated numerically. Multiple strip heat sources are flushed-mounted on the bottom surface, modeling IC chips on PCBs. Two different flow patterns were observed. For Re ≥ 20, and Gr ≤ 1.5 × 104, only steady longitudinal rolls appear in the channel. The discontinuous deployment of heat sources on the bottom makes the longitudinal rolls expand and shrink periodically. The unsteady flow consists of steady longitudinal rolls near the side walls and traveling transverse rolls at the core region of the channel. The traveling velocity of the transverse rolls was found to be equal to the mean velocity of the forced flow. The implications of these observations to the cooling of electronic equipment are discussed.
Transient Convective Heat Transfer of Air Jet Impinging Onto a Confined Ceramic-Based MCM Disk
Authors: Su W. S. , Liu L. K. , Hung Y. H.
Published: November 2021

Transient heat transfer behavior from a horizontally confined ceramic-based MCM disk with jet impingement has been systematically explored. The relevant parameters influencing heat transfer performance are the steady-state Grashof number, jet Reynolds number, and ratio of jet separation distance to nozzle diameter. In addition, an effective time, ton, representing a certain transient time when the mixed convection effect due to jet impingement and buoyancy becomes significant relative to heat conduction, is introduced. Both the transient chip and average Nusselt numbers on the MCM disk surface decrease with time in a very beginning period of 0 ≤ t < ton, whereas it gradually increases or keeps constant with time and finally approaches the steady-state value in the period of ton ≤ t < ts. As compared with the steady-state results, if the transient chip and average heat transfer behaviors may be considered as a superposition of a series of quasi-steady states, the transient chip and average Nusselt numbers in all the present transient experiments can be properly predicted by the existing steady-state correlations when t ≥ 4 min in the power-on transient period.
Integrated Heterogeneous Design of Semiconductor Heat Sink via Scaled Direct Micro-Modeling, Upper Scale VAT Simulation and Experiment: Comparison and Verification of Properties
Authors: Travkin V. S. , Sergievsky E. D. , Krinitsky E. V. , Catton I.
Published: November 2021

The thermal and hydrodynamic characteristic of straight-channel longitudinal fin heat sink under forced air-cooling is studied experimentally and numerically using a Phoenics 3.3 (CHAM, UK) CFD software. The aim of the study is to simulate and compare the viability of employing Phoenics code as effective and efficient means gathering the vast amount of data required to adequately quantify heat sink characteristics on the lower scale with the two scale experimental data reduced according to requirements of VAT. For this case is analyzed the basic homogeneous heat transfer performance features and shown insolvency of using heat transfer and effectiveness parameter. A number of data reduction parameters and procedures were developed using scaling heterogeneous formulation by volume averaging theory (VAT). Analysis brought in this work supports the procedures used to connect the two scale VAT experiment with the full lower scale direct numerical modeling for the semiconductor heat sink.