bluuebunny/crossref_metadata_2025 huggingface dataset:
Belief About Mandatory School Vaccinations and Vaccination Refusal Among Ohio Appalachian Parents: Do Demographic and Religious Factors, General Health, and Political Affiliation Play a Role?
Authors: Krok‐Schoen Jessica L. , Bernardo Brittany M. , Weier Rory C. , Peng Juan , Katz Mira L. , Reiter Paul L. , Richardson Morgan S. , Pennell Michael L. , Tatum Cathy M. , Paskett Electra D.
Published: November 2017

Purpose

To examine how demographic, general health, religious, and political characteristics influenced beliefs about mandatory school vaccinations and history of vaccination refusal for children among Ohio Appalachian parents.

Methods

In 2013 and 2014, baseline data were obtained from parents (n = 337) of girls aged 9‐17 from 12 counties in rural Ohio Appalachia enrolled in the Community Awareness, Resources and Education (CARE II) Project. Multivariate logistic regression models were used to identify correlates of parental beliefs about mandatory school vaccinations and history of refusing a doctor‐recommended vaccine for their child(ren).

Results

About 47% of parents agreed that parents should have the right to refuse mandatory school vaccinations for their child(ren). Participants who reported their political affiliation as Republican (OR = 2.45, 95% CI: 1.28‐4.66) or Independent (OR = 3.31, 95% CI: 1.70‐6.44) were more likely to agree that parents should have the right to refuse school‐mandated vaccinations than parents who reported their political affiliation as Democrat. Approximately 39% of parents reported ever refusing a vaccine for their child(ren). Participants who were female (OR = 3.90, 95% CI: 1.04‐14.58) and believed that parents should have the right to refuse mandatory school vaccinations (OR = 3.27, 95% CI: 1.90‐5.62) were more likely to report ever refusing a vaccine for their child(ren).

Conclusion

The study findings provide information to better understand factors related to vaccination refusal among parents in Appalachia Ohio that can be used to design interventions to improve vaccination uptake.
Maintaining their genetic distance: Little evidence for introgression between widely hybridizing species of Geum with contrasting mating systems
Authors: Jordan Crispin Y. , Lohse Konrad , Turner Frances , Thomson Marian , Gharbi Karim , Ennos Richard A.
Published: November 2017

Within the plant kingdom, many genera contain sister lineages with contrasting outcrossing and inbreeding mating systems that are known to hybridize. The evolutionary fate of these sister lineages is likely to be influenced by the extent to which they exchange genes. We measured gene flow between outcrossing Geum rivale and selfing Geum urbanum, sister species that hybridize in contemporary populations. We generated and used a draft genome of G. urbanum to develop dd‐RAD data scorable in both species. Coalescent analysis of RAD data from allopatric populations indicated that the species diverged 2–3 Mya, and that historical gene flow between them was extremely low (1 migrant every 25 generations). Comparison of genetic divergence between species in sympatry and allopatry, together with an analysis of allele frequencies in potential parental and hybrid populations, provided no evidence of contemporary introgression in sympatric populations. Cluster‐ and species‐specific marker analyses revealed that, apart from four early‐generation hybrids, individuals in sympatric populations fell into two genetically distinct groups that corresponded exactly to their morphological species classification with maximum individual admixture estimates of only 1–3%. However, we did observe joint segregation of four putatively introgressed SNPs across two scaffolds in the G. urbanum population that was associated with significant morphological variation, interpreted as tentative evidence for rare, recent interspecific gene flow. Overall, our results indicate that despite the presence of hybrids in contemporary populations, genetic exchange between G. rivale and G. urbanum has been extremely limited throughout their evolutionary history.
Contemporary evolution of a Lepidopteran species, Heliothis virescens, in response to modern agricultural practices
Authors: Fritz Megan L. , DeYonke Alexandra M. , Papanicolaou Alexie , Micinski Stephen , Westbrook John , Gould Fred
Published: November 2017

Adaptation to human‐induced environmental change has the potential to profoundly influence the genomic architecture of affected species. This is particularly true in agricultural ecosystems, where anthropogenic selection pressure is strong. Heliothis virescens primarily feeds on cotton in its larval stages, and US populations have been declining since the widespread planting of transgenic cotton, which endogenously expresses proteins derived from Bacillus thuringiensis (Bt). No physiological adaptation to Bt toxin has been found in the field, so adaptation in this altered environment could involve (i) shifts in host plant selection mechanisms to avoid cotton, (ii) changes in detoxification mechanisms required for cotton‐feeding vs. feeding on other hosts or (iii) loss of resistance to previously used management practices including insecticides. Here, we begin to address whether such changes occurred in H. virescens populations between 1997 and 2012, as Bt‐cotton cultivation spread through the agricultural landscape. For our study, we produced an H. virescens genome assembly and used this in concert with a ddRAD‐seq‐enabled genome scan to identify loci with significant allele frequency changes over the 15‐year period. Genetic changes at a previously described H. virescens insecticide target of selection were detectable in our genome scan and increased our confidence in this methodology. Additional loci were also detected as being under selection, and we quantified the selection strength required to elicit observed allele frequency changes at each locus. Potential contributions of genes near loci under selection to adaptive phenotypes in the H. virescens cotton system are discussed.
Comparative ecological transcriptomics and the contribution of gene expression to the evolutionary potential of a threatened fish
Authors: Brauer Chris J. , Unmack Peter J. , Beheregaray Luciano B.
Published: November 2017

Understanding whether small populations with low genetic diversity can respond to rapid environmental change via phenotypic plasticity is an outstanding research question in biology. RNA sequencing (RNA‐seq) has recently provided the opportunity to examine variation in gene expression, a surrogate for phenotypic variation, in nonmodel species. We used a comparative RNA‐seq approach to assess expression variation within and among adaptively divergent populations of a threatened freshwater fish, Nannoperca australis, found across a steep hydroclimatic gradient in the Murray–Darling Basin, Australia. These populations evolved under contrasting selective environments (e.g., dry/hot lowland; wet/cold upland) and represent opposite ends of the species’ spectrum of genetic diversity and population size. We tested the hypothesis that environmental variation among isolated populations has driven the evolution of divergent expression at ecologically important genes using differential expression (DE) analysis and an anova‐based comparative phylogenetic expression variance and evolution model framework based on 27,425 de novo assembled transcripts. Additionally, we tested whether gene expression variance within populations was correlated with levels of standing genetic diversity. We identified 290 DE candidate transcripts, 33 transcripts with evidence for high expression plasticity, and 50 candidates for divergent selection on gene expression after accounting for phylogenetic structure. Variance in gene expression appeared unrelated to levels of genetic diversity. Functional annotation of the candidate transcripts revealed that variation in water quality is an important factor influencing expression variation for N. australis. Our findings suggest that gene expression variation can contribute to the evolutionary potential of small populations.
Perceptual expansion under cognitive guidance: Lessons from language processing
Authors: Begby Endre
Published: November 2017

This paper aims to provide an empirically informed sketch of how our perceptual capacities can interact with cognitive processes to give rise to new perceptual attributives. In section 1, I present ongoing debates about the reach of perception and direct focus toward arguments offered in recent work by Tyler Burge and Ned Block. In section 2, I draw on empirical evidence relating to language processing to argue against the claim that we have no acquired, culture‐specific, high‐level perceptual attributives. In section 3, I turn to the cognitive dimension; I outline how cognitive procedures (including conceptual representation and explicit inference) can be involved in the acquisition of what ought to, nonetheless, be recognized as genuinely perceptual capacities. Finally, in section 4, I argue for the importance of distinguishing these conclusions from more familiar and radical claims about rampant “cognitive penetration” into the perceptual domain.
Effects of voltage strength during electroporation on the development and quality of in vitro‐produced porcine embryos
Authors: Nishio K , Tanihara F , Nguyen T‐V , Kunihara T , Nii M , Hirata M , Takemoto T , Otoi T
Published: November 2017

Contents

This study was conducted to determine suitable conditions for an experimental method in which the CRISPR/Cas9 system is introduced into in vitro‐produced porcine zygotes by electroporation. In the first experiment, when putative zygotes derived from in vitro fertilization (IVF) were electroporated by either unipolar or bipolar pulses, keeping the voltage, pulse duration and pulse number fixed at 30 V/mm, 1 msec and five repeats, respectively, the rate of blastocyst formation from zygotes electroporated by bipolar pulses decreased compared to zygotes electroporated by unipolar pulses. In the second experiment, the putative zygotes were electroporated by electroporation voltages ranging from 20 V/mm–40 V/mm with five 1‐msec unipolar pulses. The rate of cleavage and blastocyst formation of zygotes electroporated at 40 V/mm was significantly lower (p < .05) than that of zygotes electroporated at less than 30 V/mm. Moreover, the apoptotic nuclei indices of blastocysts derived from zygotes electroporated by voltages greater than 30 V/mm significantly increased compared with those from zygotes electroporated by voltages less than 25 V/mm (p < .05). When zygotes were electroporated with Cas9 mRNA and single‐guide RNA (sgRNA) targeting site in the FGF10 exon 3, the proportions of blastocysts with targeted genomic sequences were 7.7% (2/26) and 3.6% (1/28) in the embryos derived from zygotes electroporated at 25 V/mm and 30 V/mm, respectively. Our results indicate that electroporation at 25 V/mm may be an acceptable condition for introducing Cas9 mRNA and sgRNA into pig IVF zygotes under which the viability of the embryos is not significantly affected.
Effectiveness of controlled internal drug release device treatment to alleviate reproductive seasonality in anestrus lactating or dry Barki and Rahmani ewes during non‐breeding season
Authors: EL‐Mokadem MY , Nour El‐Din ANM , Ramadan TA , Rashad AM , Taha TA , Samak MA , Salem MH
Published: November 2017

Contents

This study aimed to evaluate the effectiveness of hormonal treatments on ovarian activity and reproductive performance in Barki and Rahmani ewes during non‐breeding season. Forty‐eight multiparous ewes, 24 Barki and 24 Rahmani ewes were divided into two groups, 12 lactating and 12 dry ewes for each breed. Controlled internal drug release (CIDR) device was inserted in all ewes for 14 days in conjunction with intramuscular 500 IU equine chronic gonadotrophin (eCG) at day of CIDR removal. Data were analysed using PROC MIXED of SAS for repeated measures. Breed, physiological status and days were used as fixed effects and individual ewes as random effects. Barki ewes recorded higher (p < .05) total number of follicles, number of large follicles, serum estradiol concentration and estradiol: progesterone (E2:P4) ratio compared to Rahmani ewes. Lactating ewes recorded higher (p < .05) number of small follicles and lower concentration of total antioxidant capacity (TAC) compared to dry ewes. Number and diameter of large follicles recorded the highest (p < .05) values accompanied with disappearance of corpora lutea at day of mating. Serum progesterone concentration recorded lower (p < .05) value at day of mating and the highest (p < .05) value at day 35 after mating. CIDR‐eCG protocol induced 100% oestrous behaviour in both breeds, but Rahmani ewes recorded longer (p < .05) oestrous duration compared to Barki. Conception failure was higher (p < .05) in Barki compared to Rahmani ewes. In conclusion, CIDR‐eCG protocol was more potent in improving ovarian activity in Barki compared to Rahmani ewes, but this protocol seems to induce hormonal imbalance in Barki ewes that resulted in increasing conception failure compared to Rahmani ewes.
Acute stimulation of a smooth muscle constrictor by oestradiol‐17β via GPER1 in bovine oviducts
Authors: Nishie T , Kobayashi Y , Kimura K , Okuda K
Published: November 2017

Contents

Oviducts play roles in reproductive processes, including gametes transport, fertilization and early embryo development. Oviductal transport is controlled by various factors such as endothelins (EDNs) and nitric oxide (NO), smooth muscle contracting and relaxing factor, respectively. EDNs and NO production depend on an ovarian steroid hormone, oestradiol‐17β (E2) and E2 quickly exerts their biological functions through G protein‐coupled oestrogen receptor 1 (GPER1), which mediates rapid intracellular signalling. Because follicular fluid which contains a high concentration of E2 enters the oviduct, we hypothesized that E2 in the follicular fluid participates via GPER1 in producing EDNs and NO. To test this hypothesis, we investigated 1) the expression and localization of GPER1 in bovine oviductal tissues and 2) rapid effects of E2 via GPER1 on EDN1, EDN2 and inducible NO synthase (iNOS) expression in cultured bovine oviductal isthmic epithelial cells. GPER1 was observed in the oviductal epithelium, stroma and smooth muscle, and its expression was highest in the isthmus. Short‐term treatments (≤1 hr) of E2 increased EDN2 mRNA expression in the isthmic epithelial cells, although E2 did not affect EDN1 and iNOS mRNA expressions. Results of GPER1‐selective agonist G‐1 and GPER1‐selective antagonist G‐15 treatments revealed acute stimulation by E2, which is mediated via GPER1. The overall findings suggested that E2 in follicular fluid rapidly stimulates EDN2 expression via GPER1 in the isthmic epithelial cells. Follicular fluid may play a role in retention of the ovulated oocyte in the end of ampulla by contracting the isthmus for successful fertilization.
Comparative analysis of ovarian transcriptomes between prolific and non‐prolific goat breeds via high‐throughput sequencing
Authors: Zi X‐D , Lu J‐Y , Zhou H , Ma L , Xia W , Xiong X‐R , Lan D‐L , Wu X‐H
Published: November 2017

Contents

To increase the current understanding of the gene expression in the pre‐ovulatory ovary and identify the key genes involved in the regulation of ovulation rate, we compared the transcriptomes of ovaries from the prolific Jintang black goat (JTG) and the non‐prolific Tibetan goat (TBG) during the follicular phase using the Illumina RNA‐Seq method. Three ovarian libraries were constructed for each breed. On average, we obtained approximately 49.2 and 45.9 million reads for each individual ovary of TBGs and JTGs, respectively, of which 79.76% and 78.67% reads were covered in the genome database. A total of 407 differentially expressed genes (DEG) were detected between these two breeds, in which 316 were upregulated, and 91 were downregulated in the ovaries of JTGs versus TBGs. Based on the results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, some of these DEGs potentially play an important role in controlling the development of ovarian follicles. SRD5A2, MSMB, STAR and 3BHSD, etc. were the most significantly differentially expressed between these two distinct breeds. In addition, each ovary expressed 1,066 versus 989 novel transcripts, and 171,829 versus 140,529 putative SNPs in TBGs versus JTBs, respectively. All data sets (GEO and dbSNP) were available via public repositories. Our study provides insight into the transcriptional regulation of the ovaries of two distinct breeds of goats that might serve as a key resource for understanding goat fecundity. SRD5A2, MSMB, STAR and 3BHSD may be associated with the high fecundity of JTGs.
Analysis of the influence of collagen fibres in the dermis on skin optical reflectance by Monte Carlo simulation in a nine‐layered skin model
Authors: Masuda Y. , Ogura Y. , Inagaki Y. , Yasui T. , Aizu Y.
Published: November 2017

Background

Collagen fibres in the dermis play an important structural role in the skin. Age‐related changes to these fibres cause wrinkles and slackness of facial skin. However, it is not clear how dermal collagen fibres affect skin colour. The purpose of this study was to clarify the influence of altered collagen fibres on skin colour, using both experimental measurement of fibre density and Monte Carlo simulations in an optical model of skin.

Methods

Reflection spectra were measured from the cheeks of 12 Japanese women (22‐65 years old) by spectral colorimeter. Two‐dimensional autocorrelation functions were calculated from second harmonics generation (SHG) images acquired from the same locations and used to calculate collagen density indices. Monte Carlo simulations of light reflectance by skin were performed using a nine‐layered model that precisely imitates skin structure. The relationship between dermal collagen fibre density and skin reflection spectra was analysed.

Results

A positive correlation was found between collagen density and skin brightness, as measured by the colour value, L* (using the L*a*b* colour space). In addition, collagen density showed a strong inverse correlation with age and with the optical absorption of dermis. The Monte Carlo simulations showed that the reflection spectrum of skin changes when the scattering coefficient of the dermis is altered. These changes were the same for simulated and experimentally measured reflection spectra.

Conclusion

When collagen fibre density in the upper dermis is decreased with age, skin colour becomes less bright because light scattering in the skin is decreased.
“Best practice” for extracorporeal photopheresis in acute and chronic graft‐versus‐host disease by Societa’ Italiana di Emaferesi and Manipolazione Cellulare and Gruppo Italiano Trapianto Midollo Osseo: a national survey to ascertain its degree of application in Italian transplant centers
Authors: Pierelli Luca , Bosi Alberto , Olivieri Attilio
Published: November 2017

BACKGROUND

A recent “best practice” promoted and published by Gruppo Italiano Trapianto Midollo Osseo (GITMO) and Societa’ Italiana di Emaferesi and Manipolazione Cellulare (SIDEM) on the use of extracorporeal photopheresis (ECP) in acute and chronic graft‐versus‐host disease (GVHD) has been tested for the degree of agreement and application among Italian transplant centers.

STUDY DESIGN AND METHODS

Twenty‐four Italian centers coordinating a pair number of transplant programs completed the Web‐based survey within the fixed deadline, representing approximately 52% of those centers that have a GITMO‐accredited allogeneic transplant program that routinely uses ECP in GVHD.

RESULTS

The level of full agreement was more than 85% for most of the answers given by the best practice (14 of 16) to the various issues. For the answers of two questions dealing with indications of ECP in acute GVHD and with safety and quality measures we observed a full agreement of 62 and 50%, respectively.

CONCLUSION

This report shows a very good success of best practice among Italian centers, indicating that, after 3 years, it seems to be still updated and useful. More discussion has been observed for safety and quality measures and, likely, this issue deserves a dedicated focus on a future consensus report.
The Effect of Metacognitive Strategies on Prospective Teachers’ Metacognitive Awareness and Self Efficacy Belief
Authors: Yıldız Hatice , Akdağ Mustafa
Published: November 2017

The purpose of the research study was to investigate the effects of the metacognitive strategies used in the course Science and Technology Instruction-II on prospective teachers’ metacognitive awareness, science teaching self efficacy belief and teacher self efficacy belief. The research group was composed of 87 third grade students from the Primary Education Department at the Faculty of Education at Cumhuriyet University in Sivas, Turkey. Experimental method with pre-test and post-test control group was used in the study. Metacognitive Awareness Inventory, Science Teaching Efficacy Beliefs Inventory-B (STEBI-B) and Teacher Self Efficacy Beliefs Inventory were utilized as pre-test and post-test. Journals and metacognitive questions were used in experimental group training. The research findings indicated that metacognitive strategies increased the prospective teachers’ metacognitive awareness and teacher self efficacy belief but they did not increase students’ science teaching self efficacy belief so much as to constitute a significant difference between the pre-test.
The effect of high fidelity simulated learning methods on physiotherapy pre-registration education: a systematic review protocol
Authors: Roberts Fiona , Cooper Kay
Published: November 2017

Review objective:

The objective of this review is to identify if high fidelity simulated learning methods are effective in enhancing clinical/practical skills compared to usual, low fidelity simulated learning methods in pre-registration physiotherapy education.
Management of skin toxicity caused by epidermal growth factor receptor inhibitors: an evidence-based implementation project
Authors: Guo Xiaolu , Peters Micah D.J. , Lu Zhenqi
Published: November 2017

EXECUTIVE SUMMARY

Background:

Epidermal growth factor receptor inhibitors (EGFRIs) bind to and inhibit epidermal growth factor receptors (EGFRs) in cancer cells, slowing/preventing tumor growth. As a type of “targeted therapy”, they have demonstrated therapeutic effects on solid tumors including colorectal, lung, and head and neck cancers. While effective, various skin reactions are associated with EGFRI therapy which can lead to dose modification or discontinuation as well as discomfort, pain and reduced quality of life. With adequate knowledge and skills, EGFRI-induced skin toxicity can be effectively managed collaboratively by clinicians and people affected by cancer.

Objectives:

This project aimed to improve management of skin toxicity caused by EGFRIs by implementing evidence-informed practice within a chemotherapy department.

Methods:

Evidence-informed recommendations for practice and corresponding audit criteria were developed based on a series of literature reviews. Current practice was reviewed against these criteria with 19 nurses and 21 patients within a chemotherapy department. Barriers to adherence to evidence-informed practice were identified and strategies to improve compliance were implemented with clinicians and patients. A follow-up audit against the criteria was used to measure changes in clinical practice.

Results:

Multiple strategies for getting research into practice appear to have been successful. The follow-up audit demonstrated large improvements in compliance across all audit criteria in comparison with baseline results with all but one criterion achieving 100% compliance. Low rates of suspected infection meant that clinical practice could not be measured for criterion 7.

Conclusions:

Auditing current practice and implementation of strategies to improve compliance with evidence-informed practice were effective. Sustaining these improvements is vital to ensure clinical practice continues to support better patient outcomes.
Experiences of women discharged less than 24 hours post vaginal birth: a systematic review protocol
Authors: Cusack Lynette , Smith Morgan Roberta
Published: November 2017

Review question:

The objective of this qualitative review is to synthesize the best available evidence on the meaning of early hospital discharge for women following a normal vaginal birth.
Experimental Application of Time-Domain Transmissibility Identification to Fault Detection and Localization in Acoustic Systems
Authors: Aljanaideh Khaled F. , Bernstein Dennis S.
Published: November 2017

This paper considers a technique for fault detection and localization based on time-domain transmissibility identification. This technique takes the advantage of unknown external (ambient) excitation to identify a sensor-to-sensor model, which is independent of the excitation signal and the initial conditions of the underlying system. In the presence of unknown external excitation, the identified transmissibility operator is used to compute the sensor-to-sensor residual, which is the discrepancy between the predicted sensor output (based on the transmissibility operator) and the actual measurements. The sensor-to-sensor residuals are used to detect, diagnose, and localize faults in sensors and system dynamics. We consider an experimental setup consisting of an acoustic system with three speakers and six microphones. Each speaker is an actuator, and each microphone is a sensor that measures the acoustic response at its location. Measurements from the six microphones are used to construct transmissibility operators, which in turn are used to detect and localize changes in the dynamics of the acoustic system or the microphones by computing the resulting one-step residuals.
Design and Fabrication of Laser-Machined Hinge Joints on Miniature Tubes for Steerable Medical Devices
Authors: Pattanshetti Shivanand , Ryu Seok Chang
Published: November 2017

With the proliferation of successful minimally invasive surgical techniques, comes the challenge of shrinking the size of surgical instruments further to facilitate use in applications such as neurosurgery, pediatric surgery, and needle procedures. This paper introduces laser machined, multi-degree-of-freedom (DOF) hinge joints embedded on tubes, as a possible means to realize such miniature instruments without the need for any assembly. A method to design such a joint for an estimated range of motion was explored. The effects of design and machining parameters on the mechanical interference, range of motion, and joint dislocation were analyzed. The extent of interference between the moving parts of the joint can be used to predict the range of motion of the joint for rigid tubes and future design optimization. The total usable workspace was also estimated using kinematic principles for a joint in series and for two sets of orthogonal joints. Our work can open up avenues to a new class of miniature robotic medical devices with hinge joints and a usable channel for drug delivery.
An Efficient Nonstandard Finite Difference Scheme for a Class of Fractional Chaotic Systems
Authors: Hajipour Mojtaba , Jajarmi Amin , Baleanu Dumitru
Published: November 2017

In this paper, we formulate a new nonstandard finite difference (NSFD) scheme to study the dynamic treatments of a class of fractional chaotic systems. To design the new proposed scheme, an appropriate nonlocal framework is applied for the discretization of nonlinear terms. This method is easy to implement and preserves some important physical properties of the considered model, e.g., fixed points and their stability. Additionally, this scheme is explicit and inexpensive to solve fractional differential equations (FDEs). From a practical point of view, the stability analysis and chaotic behavior of three novel fractional systems are provided by the proposed approach. Numerical simulations and comparative results confirm that this scheme is also successful for the fractional chaotic systems with delay arguments.
Response of a Harmonically Forced Dry Friction Damped System Under Time-Delayed State Feedback
Authors: Mitra R. K. , Banik A. K. , Chatterjee S.
Published: November 2017

Nonlinear dynamics, control, and stability analysis of dry friction damped system under state feedback control with time delay are investigated. The dry friction damped system is harmonically excited, and the nonlinearities in the equation of motion arise due to nonlinear damping and spring force. In this paper, a frequency domain-based method, viz., incremental harmonic balance method along with arc-length continuation technique (IHBC) is first employed to identify the primary responses which may be present in such system. The IHBC is then reformulated in a manner to treat the dry friction damped system under state feedback control with time delay and is applied to obtain control of responses in an efficient and systematic way. The stability of uncontrolled responses is obtained by Floquet's theory using Hsu' scheme, and the stability of the controlled responses is obtained by applying a semidiscretization method for delay differential equation (DDE).
Complete and Simplified Models for Estimating Vibration Instability of Cyclically Symmetric Ring Structures: Comparison and Verification
Authors: Wang Shiyu , Zhang Penghui , Sun Wenjia
Published: November 2017

In-plane vibration of cyclically symmetric ring structures is examined with emphasis on the comparison of instabilities estimated by complete and simplified models. The aim of this paper is to understand under what conditions and to what degree the simplified models can approach the complete model. Previous studies develop time-variant models and employ perturbation method by assuming weak support. This work casts the rotating-load problem into a nonrotating load problem. A complete model with time-invariant coefficients is developed in rotating-support-fixed frame, where the bending and extensional deformations are incorporated. It is then reduced into two simplified ones based on different deformation restrictions. Due to the time-invariant effect observed in the rotating-support-fixed frame, the eigenvalues are formulated directly by using classical vibration theory and compared based on a sample structure. The comparisons verify that the two types of models are comparable only for weak support. Furthermore, the simplified models cannot accurately predict all unstable behaviors in particular for strong support. The eigenvalues are different even in comparable regions. For verification purpose, the time-invariant models are transformed into time-variant ones in the inertial frame, based on which instabilities are estimated by using Floquét theory. Consistence between the time-invariant and -variant models verifies the comparisons.
A General Expression for the Stagnant Thermal Conductivity of Stochastic and Periodic Structures
Authors: Bai X. , Hasan C. , Mobedi M. , Nakayama A.
Published: November 2017

A general expression has been obtained to estimate thermal conductivities of both stochastic and periodic structures with high-solid thermal conductivity. An air layer partially occupied by slanted circular rods of high-thermal conductivity was considered to derive the general expression. The thermal conductivity based on this general expression was compared against that obtained from detailed three-dimensional numerical calculations. A good agreement between two sets of results substantiates the validity of the general expression for evaluating the stagnant thermal conductivity of the periodic structures. Subsequently, this expression was averaged over a hemispherical solid angle to estimate the stagnant thermal conductivity for stochastic structures such as a metal foam. The resulting expression was found identical to the one obtained by Hsu et al., Krishnan et al., and Yang and Nakayama. Thus, the general expression can be used for both stochastic and periodic structures.
Investigation of Porosity and Mechanical Properties of Graphene Nanoplatelets-Reinforced AlSi10 Mg by Selective Laser Melting
Authors: Wang Yachao , Shi Jing , Lu Shiqiang , Xiao Weihan
Published: November 2017

Graphene possesses many outstanding properties, such as high strength and light weight, making it an ideal reinforcement for metal matrix composite (MMCs). Meanwhile, fabricating MMCs through laser-assisted additive manufacturing (LAAM) has attracted much attention in recent years due to the advantages of low waste, high precision, short production lead time, and high flexibility. In this study, graphene-reinforced aluminum alloy AlSi10 Mg is fabricated using selective laser melting (SLM), a typical LAAM technique. Composite powders are prepared using high-energy ball milling. Room temperature tensile tests are conducted to evaluate the mechanical properties. Scanning electron microscopy observations are conducted to investigate the microstructure and fracture surface of obtain composite. It is found that adding graphene nanoplatelets (GNPs) significantly increases porosity, which offsets the enhancement of tensile performance as a result of GNPs addition. Decoupling effort is then made to separate the potential beneficial effects from GNPs addition and the detrimental effect from porosity increase. For this purpose, the quantitative relationship between porosity and material strength is obtained. Taking into consideration the strength reduction caused by the increased porosity, the strengthening effect of GNPs turns out to be significant, which reaches 60.2 MPa.
Effects of Linear Filter on Stability and Performance of Human-in-the-Loop Model Reference Adaptive Control Architectures
Authors: Yousefi Ehsan , Demir Didem Fatma , Sipahi Rifat , Yucelen Tansel , Yildiz Yildiray
Published: November 2017

Model reference adaptive control (MRAC) can effectively handle various challenges of the real world control problems including exogenous disturbances, system uncertainties, and degraded modes of operations. In human-in-the-loop settings, MRAC may cause unstable system trajectories. Basing on our recent work on the stability of MRAC-human dynamics, here we follow an optimization based computations to design a linear filter and study whether or not this filter inserted between the human model and MRAC could help remove such instabilities, and potentially improve performance. To this end, we present a mathematical approach to study how the error dynamics of MRAC could favorably or detrimentally influence human operator’s error dynamics in performing a certain task. An illustrative numerical example concludes the study.
An Artificial Potential Field Approach to Simulate Cooperative Adaptive Cruise Controlled Vehicles
Authors: McCrone D. Jordan , Arasteh Ehsan , Jan Fahad M.
Published: November 2017

This paper presents artificial potential field functions to assist adaptive cruise control and cooperative adaptive cruise control vehicles in a multi-lane highway in two dimensions. The artificial field functions consist of three potential fields: road potential, car potential, and velocity potential. The artificial potential field is constructed in a way to assist the vehicles in lane-keeping, speed preference, platoon forming, and obstacle avoidance. The artificial roadway barriers are constructed to keep the car on the highway, and lane boundaries are constructed so that vehicles can overcome the boundary in case lane changing is needed. Also, the shape of the velocity potential is to allow vehicles to either slow down or speed up depending on the surroundings. Static and dynamic obstacles detected by vehicle sensors are superimposed onto these potential fields. Hierarchical control schemes are introduced on top of these inherently reactive potential fields, resulting in stable platoons with short following times. A MATLAB code was generated to show that under our simulated parameters a platoon of vehicles demonstrates good throughput and traffic safety.
Control of Dynamic Systems Using Time Scaling
Authors: Rairán J. D.
Published: November 2017

Human brain capabilities to control are undeniable, but embedding that capacity in an algorithm for the control of a dynamic system has proven limited by natural human bounds such as the reaction time, which restricts the number of industrial applications using a human in the loop. Thus, the authors of this paper propose a new procedure to scale linear systems in time, which makes human control of dynamic systems not only feasible but also comfortable. The scaling method comprises moving poles and zeros of a transfer function proportionally to a scaling factor. Thus, a person controls the scaled version of the system, while the computer acquires his/her reactions, then a neural network learns those reactions. This network controls both scaled and original systems. The new control strategy controls slow and fast systems, as well as stable and unstable systems, achieving high performance for all conditions. Appropriate time scaling, and practice, facilitate the control of any dynamic system.
Controlling Solar Photovoltaic Cells Utilizing Polymer-Dispersed Liquid Crystal Technology
Authors: Baayoun Hanie O. , Chen Zheng
Published: November 2017

Solar charge controllers are currently a necessary piece of equipment when utilizing the energy from a photovoltaic system for charging purposes. However, a standard solar charge controller available today includes some drawbacks that may be crucial for specific applications. An alternate method of regulating energy from a photovoltaic panel can be accomplished by utilizing polymer-dispersed liquid crystal (PDLC) technology. Combining a solar panel with a proper PDLC material allows the input into the photovoltaic panel to be controlled. This method of power regulation can lead to increased efficiency, reduced cost, reduced weight, and increased safety when compared to a standard solar charge controller.
Realtime Application of Progressive Optimal Search and Adaptive Dynamic Programming in Multi-Source HEVs
Authors: M. Ali Ahmed , Söffker Dirk
Published: November 2017

In multi-source hybrid electric vehicles (HEVs), more degrees of freedom are introduced to the power management optimization problem. Formulation of the optimal control problem and selection of solution method significantly affect the realtime applicability of the developed strategy. Moreover, elaborate definition of objective cost function and control variables are the essences to approach the global optimal solution in real-time. In this paper, two novel developed concepts are introduced: Adaptive Dynamic Programming (ADP) and Progressive Optimal Search (POS). The problem definition and solution method are structured in each method to yield minimum fuel consumption and suit realtime applicability. The results are comparatively analyzed with respect to previous developed methods of rule-based (RB) and adaptive RB. Experimental application of the developed methods is conducted using a hardware-in-the-loop (HIL) test-rig to validate the control modules. The comparative analysis emphasizes the advantages of each method from the perspectives of trip cost minimization, charge sustenance, and realtime applicability.
Design of a Wind Tunnel Test Section for Single Airfoil Configuration With Real-Time Lift Force Control
Authors: Aguiar da Franca Aline , Abel Dirk
Published: November 2017

This article presents a concept of test section for a closed-return wind tunnel, where the lift force of an airfoil, which depends on the angle of attack, is controlled in real-time. This airfoil is used to represent a wind turbine blade. The lift force of the blades is what produces the rotor torque of the wind turbine. This torque determines the amount of energy that will be captured by the wind turbine. The linear dynamics of the motor used to change the angle of attack and the static non-linearity of the airfoil are modeled as a Wiener model. The Quadratic Dynamic Matrix Controller based on Wiener model with linearizing pre-compensation is implemented to keep the lift force constant, which is desirable to avoid mechanical loads for wind turbine applications.
An Explicit Decision Tree Approach for Automated Driving
Authors: Li Nan , Chen Hao , Kolmanovsky Ilya , Girard Anouck
Published: November 2017

In this paper, an explicit decision tree approach for automated driving is proposed. The ego vehicle operates in traffic that is modeled as a discrete-time Markov chain, the state of which is only partially observable. In this setting, the automated driving policy is generated from a decision tree algorithm offline operation to create an explicit implementation for the online use. Simulation results of an implementation of this approach for automated driving on a two-lane highway are reported to illustrate the potential of this approach.
Frequency Constrained Adaptive PID Laws for Motion Control Systems
Authors: Hsiao Tesheng , Cheng Chung-Chiang
Published: November 2017

The proportional-integral-derivative (PID) controller is widely used in motion control systems due to its simplicity and effectiveness. To achieve satisfactory performance, the PID parameters must be properly tuned. Although numerous PID tuning methods were investigated in the past, most of them were based on either time-domain or frequency-domain responses, while integration of features in both domains for PID tuning was less addressed. However, many industrial practitioners still found it difficult to compromise multiple conflicting control objectives, such as fast responses, small overshoot and tracking errors, and good robustness, with PID controllers. Moreover, it is desirable to adjust PID parameters online such that plant variations and unexpected disturbances can be compensated for more efficiently. In view of these requirements, this paper proposes an adaptive PID control law that updates its parameters online by minimizing the time-domain tracking errors subject to frequency-domain constraints that are imposed for loop shaping. By combining optimization criteria in both time and frequency domains for online parameter adjustment, the proposed PID controller can achieve good tracking performance with adequate robustness margin. Then the proposed PID law is applied to control an XZ-table driven by AC servo motors. Experimental results show that the tracking performance of the proposed controller is superior to that of a constant-gain PID controller whose parameters were tuned by the commercial Matlab/Simulink PID tuner.
Justifying the Stabilization of a Marginally Stable Ship
Authors: Shekhtman David , Luchtenburg Dirk M.
Published: November 2017

As a precursor to capsize, marginal stability, resulting from incorrect loading conditions and crew negligence, poses a serious danger to ships. Therefore, as a benchmark problem for preventing capsize, the use of an actively controlled pendulum for the stabilization of a marginally stable ship was analyzed. Lyapunov stability criteria and closed loop eigenvalues were used to evaluate the extent to which a proposed pendulum controller could cope with different ship stability conditions. Equations of motion were solved to observe the controller’s performance under different damping conditions. The behavior of the controller yielded the following results: a marginally stable ship can be stabilized, as long as there is no right hand plane zero; energy dissipation is key to the stabilization of a marginally stable ship; the controller must have knowledge of the ship’s stability to prevent controller-induced excitation; and a stabilized tilted ship is more robust to external disturbances than a stabilized upright ship.
Closed-Loop Control of the Frequency Response of the Virtual Brain Model
Authors: Beauchene Christine , Leonessa Alexander , Roy Subhradeep , Simon James , Abaid Nicole
Published: November 2017

The brain is a highly complex network and analyzing brain connectivity is a nontrivial task. Consequently, the neuroscience community created a large-scale, customizable, mathematical model which simulates brain activity called The Virtual Brain (TVB). Using TVB, we seek to control electroencephalography (EEG) measured brain states using auditory inputs, through TVB. A safe non-invasive brain stimulation method is binaural beats (BB) which arise from the brain’s interpretation of two pure tones, with a small frequency mismatch, delivered independently to each ear. A third phantom BB, whose frequency is equal to the difference of the two presented tones, is produced. This paper details the development and proof-of-concept testing of a simulation environment for an EEG-based closed-loop control of TVB using BB. Results suggest that the connectivity networks, constructed from simulated EEG, may change with certain BB stimulation frequency. In this work, we demonstrate that a linear controller can successfully modulate TVB connectivity.
Dispersion Number Identification in an Imbert Gasifier Under Parameter Uncertainty
Authors: Santamaria-Padilla Luis , Alvarez-Icaza Luis , Alvarez Jesus
Published: November 2017

The problem of identifying the dispersion number associated with the convective-radiative heat dispersion mechanism in an experimental gasification tubular reactor is addressed. The dependency of temperature response characteristics on the intensity and duration of a heat pulse input are characterized on the basis of a set of off-line experiments, finding that for the range of interest: (i) the coefficient of variation of the temporal temperature response depends almost linearly on the dispersion number, and (ii) the related function is robustly invertible with respect to model and experimental uncertainty. This results establishes the feasibility of identifying the key heat dispersion (inverse Peclet) number from a reasonable on-line heat pulse injection test.
Position and Linear Velocity Estimation for Position-Based Visual Servo Control of an Aerial Robot in GPS-Denied Environments
Authors: Guo Dejun , Leang Kam K.
Published: November 2017

This paper presents a new nonlinear adaptive vision-based observer to estimate position and linear velocity information for closed-loop position-based visual servo control of an aerial robot in GPS-denied environments. Specifically, the observer determines the position and linear velocity of the robot for closed-loop control by observing using a low-cost on-board camera at least two feature points fixed in the world frame. The nonlinear adaptive observer takes advantage of the geometry of perspective projection, and is designed to update position and velocity information in real-time. Thus, there are no constraints or assumptions on the depth and initial estimation errors. Furthermore, the proposed parameter estimator addresses the challenge in situations where GPS signals may be weak, unreliable, or nonexistent, such in valleys, canyons, and between tall buildings, or inside of a building and under dense canopy. For closed-loop tracking control using the estimated position and velocity information, a backstepping controller is employed for the underactuated aerial robot system. The Lyapunov method is used to show stability of the closed-loop system. Simulation and experimental results are presented that validate the performance of the observer and control system for hovering and tracking a circular trajectory, where both are defined in the world (lab) frame.