bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐term effect of methotrexate for childhood atopic dermatitis
Authors: Purvis Diana , Lee Martin , Agnew Karen , Birchall Nick , Dalziel Stuart R
Published: April 2019

Aim

To evaluate methotrexate (MTX) for paediatric atopic dermatitis (AD) while on and post‐treatment.

Methods

Medical records of children prescribed MTX for AD between 2011 and 2016 at Starship Children's Hospital, Auckland, New Zealand, were reviewed for demographics, dose and duration of MTX and hospitalisations for AD. In the follow‐up by telephone in 2017, parents of the patients reported response on MTX, AD relapses and use of additional systemic treatment and completed a patient‐oriented eczema measure (POEM).

Results

Forty‐three patients aged 2–16 years were included. Four (9%) had previous systemic treatment, and 14 (33%) were hospitalised (28 admissions). MTX was given at median dose of 0.33 mg/kg (interquartile range (IQR) 0.26–0.40) for a median of 17 months (IQR 7.5–20). After initiating MTX, only six (14%) were hospitalised (nine admissions). Thirty (70%) parents of patients were followed up for a median of 29 months (IQR 14–45) after discontinuing MTX. Five (17%) reported ‘no change’, 2 (7%) ‘slightly better’ and 23 (77%) ‘a lot better’ AD on MTX. Of the 25 who responded to MTX, AD relapsed in 10 (40%) at a median of 24 months post‐MTX; only four (16%) restarted MTX. Median POEM at follow‐up was 6 (IQR 1–17). Eleven (37%) were clear (POEM 0–2), 11 (37%) had mild to moderate AD (POEM 3–16), and 8 (27%) had severe AD (POEM ≥17).

Conclusions

Although a natural resolution cannot be excluded, MTX for severe AD was effective and well tolerated. Improvement was reported by 83%, and AD hospitalisation reduced by half. At a median of 2 years after discontinuing MTX, one third were clear, and one third had mild to moderate AD, suggesting persistence of benefit post‐MTX.
From Shape Shifting to Collusion in Violence: An Ethnography of Informal Relationships Between Bangladeshi Members of Parliament and Their Constituents
Authors: Ahmed Zahir
Published: April 2019

Based on an ethnography of relationships between members of Parliament (MPs) and their constituents in Bangladesh, this article shows how social and political relationships are entangled and performed, and how MPs are viewed by others and how they see themselves. Despite the diversity of politicians and constituents, some aspects of these relationships cut across MPs’ age, gender, and political background. I argue that these messy and contradictory relationships require MPs to be shape‐shifters. When MPs transgress to collude with one group of constituents to marginalize others—or even to commit violence—the representative role breaks down. Such disruptions mean understandings of representation have to be reconceptualized. Knowing how MPs make choices between competing and conflicting interests among their constituencies could enrich debates about their role specifically and about democracy more generally.
Gaza 2014 and Mizraḥi Feminism
Authors: Lavie Smadar
Published: April 2019

What is the relationship between Mizraḥi feminism and Israeli ultranationalism? What is the relevance of gender justice activism to Operation Protective Edge (the 2014 Gaza War) and Israel's foreign policy? Mizraḥi protests dissipate and disappear when the Israel‐Palestine conflict dominates the headlines. This essay connects intra‐Jewish racial and gendered dynamics to the 2014 Gaza War. It tracks sequences that began with social protest and ended with elections that bolstered Israel's political right wing. In between came bloodletting between the Israeli Defense Forces, the Palestinian Authority, and Israel's neighboring Arab states. The 2014 Gaza War was a watershed not only for the Israel‐Palestine conflict; under the smokescreen of war, Israel accelerated neoliberal economic reforms. The first victims of this restructuring were Mizraḥi single mothers. Palestinians, however, would pay the highest price for Israel's Mizraḥi‐Ashkenazi rift.
The WRKY transcription factor WRKY8 promotes resistance to pathogen infection and mediates drought and salt stress tolerance in Solanum lycopersicum
Authors: Gao Yong‐Feng , Liu Ji‐Kai , Yang Feng‐Ming , Zhang Guo‐Yan , Wang Dan , Zhang Lin , Ou Yong‐Bin , Yao Yin‐An
Published: April 2019

WRKY transcription factors play a key role in the tolerance of biotic and abiotic stresses across various crop species, but the function of some WRKY genes, particularly in tomato, remains unexplored. Here, we characterize the roles of a previously unstudied WRKY gene, SlWRKY8, in the resistance to pathogen infection and the tolerance to drought and salt stresses. Expression of SlWRKY8 was up‐regulated upon Pseudomonas syringae pv. tomato DC3000 (Pst. DC3000), abiotic stresses such as drought, salt and cold, as well as ABA and SA treatments. The SlWRKY8 protein was localized to the nucleus with no transcription activation in yeast, but it could activate W‐box‐dependent transcription in plants. The overexpression of SlWRKY8 in tomato conferred a greater resistance to the pathogen Pst. DC3000 and resulted in the increased transcription levels of two pathogen‐related genes SlPR1a1 and SlPR7. Moreover, transgenic plants displayed the alleviated wilting or chlorosis phenotype under drought and salt stresses, with higher levels of stress‐induced osmotic substances like proline and higher transcript levels of the stress‐responsive genes SlAREB, SlDREB2A and SlRD29. Stomatal aperature was smaller under drought stress in transgenic plants, maintaining higher water content in leaves compared with wild‐type plants. The oxidative pressure, indicated by the concentration of hydrogen peroxide (H2O2) and malondialdehyde (MDA), was also reduced in transgenic plants, where we also observed higher levels of antioxidant enzyme activities under stress. Overall, our results suggest that SlWRKY8 functions as a positive regulator in plant immunity against pathogen infection as well as in plant responses to drought and salt stresses.
Optimization of agar extraction from local seaweed species, Gracilaria salicornia in Tanzania
Authors: Vuai Said Ali Hamad , Mpatani Farid
Published: April 2019

This study aimed to develop agar extraction protocols for Gracilaria salicornia from Tanzania and investigate its physico‐chemical characteristics. A 33 factorial experimental design was used in the extraction of agar whereby three independent variables of NaOH concentration (10, 20 and 30% w/v), alkali pre‐treatment duration (0.5, 1 and 2 h) and extraction temperatures (115, 120 and 125°C) were used to determine the optimum conditions for production of high‐quality agar. Agar yield, gel strength, sulfate content, gelling and melting temperatures were evaluated as dependent variables. The optimal condition was observed at 30% NaOH concentration, 2 h alkali pre‐treatment duration and 120°C extraction temperature. The yield, gel strength, sulfate content, gelling and melting temperatures of the agar obtained under these conditions were 26.9 ± 0.7%, 510.3 ± 16.2 g cm−2, 0.29 ± 0.04%, 39.3°C and 88.4°C, respectively. These properties are very close to that of imported commercial agar. It was concluded that the local agar is capable of replacing imported agar for most general purposes. This offers a new possibility of using quality local agar in place of commercial agar.
Emotional regulation as a mediator between the filial behaviour of the oldest son and subjective well‐being of older parents in Pakistan
Authors: Hassan Sumara Masood Ul , Hamid Tengku Aizan , Haron Sharifah Azizah , Ibrahim Rahimah
Published: April 2019

Background

The link between the filial behaviour of an adult child and older parents’ well‐being is well entrenched, and theoretical evidence has indicated that it may be mediated by emotional regulation. Therefore, the current study aimed to examine whether emotional regulation (i.e. cognitive reappraisal and suppression) mediates the association between filial behaviour of the oldest son (i.e. the filial behaviour of respect and filial behaviour of daily maintenance) and subjective well‐being in older parents.

Methods

This correlational study recruited 400 community‐dwelling older parents in Rawalpindi Pakistan through a multistage cluster random sampling technique. Subjective well‐being was measured by Concise Measure of Subjective Well‐being; filial behaviour was examined through receipt of 12 domains; emotional regulation was assessed by using the Emotional Regulation Questionnaire. The structural equation modelling was employed to test the mediation effects.

Results

Cognitive reappraisal was found to partially mediate the relationship between filial behaviour of respect and subjective well‐being (β in direct model = 0.661, P < 0.000; β in full mediational model = 0.327, P < 0.000), but it failed to mediate between filial behaviour of daily maintenance and subjective well‐being (β in direct model = 0.080, P = 0.149; β in full mediational model = 0.030, P = 0.362). Moreover, suppression did not exert mediation effects in the associations between the filial behaviour of respect and subjective well‐being (β = 0.003, P = 0.338); and filial behaviour of daily maintenance and subjective well‐being (β = −0.004, P = 0.221).

Conclusions

Taken together, the results suggest that different dimensions of the filial behaviour of the oldest son exert differential effects on emotional regulation and subjective well‐being in older parents. Based on the current findings, there is a need to develop adaptive emotional regulatory capacity intervention programs for the development and enhancement of subjective well‐being in older parents within their familial context.
Chronic inflammation during osteoarthritis is associated with an increased expression of CD161 during advanced stage
Authors: Sachdeva Meenakshi , Aggarwal Aditya , Sharma Ravi , Randhawa Arpan , Sahni Daisy , Jacob Justin , Sharma Vinit , Aggarwal Anjali
Published: April 2019

Increasing evidence suggests a role of inflammation during the pathogenesis of osteoarthritis (OA). The local and systemic inflammation was studied in 33 patients of different KL grades, grade2 (n = 11), grade3 (n = 6) and grade4 (n = 16). The levels of cytokines, adipokines and matrix metalloproteinases (MMPs) were measured in serum and synovial fluid (SF) by flow cytometry and ELISA, respectively. The frequency of T cells and CD161 expression was measured by flow cytometry. The levels of IL‐1β, IL‐6 and IL‐10 were significantly higher in sera and SF of patients with OA as compared to healthy control's serum. Higher levels of MMP9 and leptin and lower levels of adiponectin were observed in SF as compared to serum. The MMP9 in SF and MMP13 levels in serum and SF decreased in KL grade 4 cases. In these patients, higher levels of leptin and lower levels of adiponectin were observed in SF versus patients of lower grades. There was increased infiltration of CD8+ T cells in SF of OA cases with decreased frequency in grade 4 cases. The expression of CD161 on T cells was significantly higher in SF than peripheral blood with significant upregulation in grade 4 patients. The CD161 expression had significant positive correlation with IL‐17 in the serum of patients. The ROC curves of CD161 expression significantly distinguished grade 2 and grade 4 patients. Collectively, an elevated CD161 expression on T cells in circulation and synovial compartment clearly distinguished lower and higher grade patients warranting studies to assess its role as a contributing factor towards OA progression.
From Tai‐isation to Lao‐isation: Ethnic changes in the longue durée in Northern Laos
Authors: Évrard Olivier
Published: April 2019

This article uses ethnographic data collected since 1994 in Northern Laos to reassess the modalities of Tai cultural and political influence on the Khmu, a Mon‐Khmer‐speaking highland population, and to understand why, after so many years of ‘Tai‐isation’, distinct identities still exist. For Grant Evans, who conducted fieldwork in Tai‐Dam and Sing Moon (Ksing Mul) villages at the end of the 1980s, the answer lay in the fundamentally dualistic character of Tai‐isation, which both favours assimilation and also tends to perpetuate interethnic boundaries. I will here insist on the fact that Tai‐isation does not imply only the influence of the Tai on the highland peoples’ way of life but also how the latter adapt themselves to this influence with their own cultural resources. Tai‐isation is traditionally an inclusive and therefore ambivalent process which can lead both to the assimilation of some highlanders and simultaneously to the emergence of new identity markers, myths or categories, which transform and structure interethnic relationships. State‐building and Lao nationalism have nonetheless profoundly reshaped these dynamics and Lao‐isation now operates in a radically different conceptual framework.
The genome of cowpea (Vigna unguiculata [L.] Walp.)
Authors: Lonardi Stefano , Muñoz‐Amatriaín María , Liang Qihua , Shu Shengqiang , Wanamaker Steve I. , Lo Sassoum , Tanskanen Jaakko , Schulman Alan H. , Zhu Tingting , Luo Ming‐Cheng , Alhakami Hind , Ounit Rachid , Hasan Abid Md. , Verdier Jerome , Roberts Philip A. , Santos Jansen R.P. , Ndeve Arsenio , Doležel Jaroslav , Vrána Jan , Hokin Samuel A. , Farmer Andrew D. , Cannon Steven B. , Close Timothy J.
Published: April 2019

Cowpea (Vigna unguiculata [L.] Walp.) is a major crop for worldwide food and nutritional security, especially in sub‐Saharan Africa, that is resilient to hot and drought‐prone environments. An assembly of the single‐haplotype inbred genome of cowpea IT97K‐499‐35 was developed by exploiting the synergies between single‐molecule real‐time sequencing, optical and genetic mapping, and an assembly reconciliation algorithm. A total of 519 Mb is included in the assembled sequences. Nearly half of the assembled sequence is composed of repetitive elements, which are enriched within recombination‐poor pericentromeric regions. A comparative analysis of these elements suggests that genome size differences between Vigna species are mainly attributable to changes in the amount of Gypsy retrotransposons. Conversely, genes are more abundant in more distal, high‐recombination regions of the chromosomes; there appears to be more duplication of genes within the NBS‐LRR and the SAUR‐like auxin superfamilies compared with other warm‐season legumes that have been sequenced. A surprising outcome is the identification of an inversion of 4.2 Mb among landraces and cultivars, which includes a gene that has been associated in other plants with interactions with the parasitic weed Striga gesnerioides. The genome sequence facilitated the identification of a putative syntelog for multiple organ gigantism in legumes. A revised numbering system has been adopted for cowpea chromosomes based on synteny with common bean (Phaseolus vulgaris). An estimate of nuclear genome size of 640.6 Mbp based on cytometry is presented.
Application of Bacterial Foraging Algorithm in The Allocation of DSTATCOM in 50-bus Canteen Feeder
Authors: Musa Umar , Mati Abdullahi Abdullahi , Yuvaraj Tangaraj
Published: April 2019

Voltage instability has been identified as the most critical factor responsible for poor power quality in electric power systems. The high losses experienced at the distribution level of these systems has become a major concern to power system operators, with about 10-13% of the total generation being dissipated as heat. Maintaining the system voltage within an acceptable limit will go a long way in reducing these losses and enhancing the overall system operational capability. The objective of this paper is to improve the voltage magnitude and reduce overall power losses in an existing 50-bus radial distribution feeder via the allocation of Distribution Static Compensator (DSTATCOM) using an established bacterial foraging algorithm (BFA) based model. The application of the swarm-based meta-heuristic model is extended to a three-quarter (75%) loading condition of the standard IEEE 33-bus test network and then, employed on the 50-bus Canteen feeder for both normal (100%) and three-quarter (75%) loading conditions. Comprehensive analysis was performed for both networks and the results were compared with their respective base-case scenarios. The final results of the evaluation obtained through simulation showed appreciable reduction in power losses and improvement in overall voltage profile with the allocation of DSTATCOM in both networks using the BFA based model. Voltage improvement in the region of 20.04% and active power loss reduction of 24.86% were recorded for three-quarter loading of the IEEE test network. For the 50-bus Canteen feeder, an overall voltage profile improvement of 6.13% and active power loss reduction of 22.84% were achieved for normal loading condition, whereas 2.99% and 19.71% improvement in total voltage profile and active power loss respectively were attained under three-quarter loading condition.
Aircraft Position Estimation Comparison of Multilateration System Lateration Algorithms with Different Reference Selection Techniques
Authors: Shehu Yaro Abdulmalik
Published: April 2019

The lateration algorithm is used by the multilateration (MLAT) system to estimation the position of an aircraft using a time difference of arrival (TDOA) measurement vector generated from its transponder emissions detected at spatially deployed ground station (GS)s. The accuracy at which the aircraft position is determined by the lateration algorithm depends on several factors two of which are the choice and number of reference GSs used in generating the TDOA measurement vector. This paper compares the aircraft PE accuracy of a lateration algorithm using TDOA measurement vector generated using a single and double GS reference selection techniques which are respectively based on signal-to-noise (SNR) and condition number computations. The PE accuracy comparison is carried out at some selected aircraft positions with the GSs in a square configuration distribution. Monte Carlo (MC) simulation result shows that the PE error obtained by the lateration algorithm using TDOA measurement vector generated with the double GS reference selection technique is on the average 20% less than that obtained using the single GS reference selection technique.
Personalized Design of Functional Gradient Bone Tissue Engineering Scaffold
Authors: Chen Wei , Dai Ning , Wang Jinqiang , Liu Hao , Li Dawei , Liu Lele
Published: April 2019

The porous structure of the natural bone not only has the characteristics of lightweight and high strength but also is conducive to the growth of cells and tissues due to interconnected pores. In this paper, a novel gradient-controlled parametric modeling technology is presented to design bone tissue engineering (BTE) scaffold. First of all, the method functionalizes the pore distribution in the bone tissue, and reconstructs the pore distribution of the bone tissue in combination with the pathological analysis of the bone defect area of the individual patient. Then, based on the reconstructed pore distribution, the Voronoi segmentation algorithm and the contour interface optimization method are used to reconstruct the whole model of the bone tissue. Finally, the mechanical properties of the scaffold are studied by the finite element analysis of different density gradient scaffolds. The results show that the method is highly feasible. BTE scaffold can be designed by irregular design methods and adjustment of pore distribution parameters, which is similar with natural bone in structural characteristics and biomechanical properties
Evaluation of Force Sensing Resistors for the Measurement of Interface Pressures in Lower Limb Prosthetics
Authors: Swanson Eric C. , Weathersby Ethan J. , Cagle John C. , Sanders Joan E.
Published: April 2019

Understanding the pressure distributions at the limb-socket interface is essential to the design and evaluation of prosthetic components for lower limb prosthesis users. Force sensing resistors (FSRs) are employed in prosthetics research to measure pressure at this interface due to their low cost, thin profile, and ease of use. While FSRs are known to be sensitive to many sources of error, few studies have systematically quantified these errors using test conditions relevant to lower limb prosthetics. The purpose of this study was to evaluate FSR accuracy for the measurement of lower limb prosthetics interface pressures. Two FSR models (Flexiforce A201 and Interlink 402) were subjected to a series of prosthetic-relevant tests. These tests included: (1) static compression, (2) cyclic compression, and (3) a combined static and cyclic compression protocol mimicking a variable activity (walk–sit–stand) procedure. Flexiforce sensors outperformed Interlink sensors and were then subjected to two additional tests: (4) static curvature and (5) static shear stress. Results demonstrated that FSRs experienced significant errors in all five tests. We concluded that: (1) if used carefully, FSRs can provide an estimate of prosthetic interface pressure, but these measurements should be interpreted within the expected range of possible measurement error given the setup; (2) FSRs should be calibrated in a setup that closely matches how they will be used for taking measurements; and (3) both Flexiforce and Interlink sensors can be used to estimate interface pressures; however, in most cases Flexiforce sensors are likely to provide more accurate measurements.
Basin of Attraction and Limit Cycle Oscillation Amplitude of an Ankle-Hip Model of Balance on a Balance Board
Authors: Chumacero-Polanco Erik , Yang James
Published: April 2019

The study of upright posture (UP) stability is of relevance to estimating risk of falls, especially among people with neuromuscular deficits. Several studies have addressed this problem from a system dynamic approach based on parameter bifurcation analyses, which provide the region of stability (RoS) and the delimiting bifurcation curves (usually Hopf and pitchfork) in some parameter-spaces. In contrast, our goal is to determine the effect of parameter changes on the size of the basin of attraction (BoA) of the UP equilibrium and the amplitude of the limit cycle oscillations (LCOs) emerging from the Hopf bifurcations (HBs). The BoA is an indicator of the ability of the UP to maintain balance without falling, while LCOs may explain the sway motion commonly observed during balancing. In this study, a three degree-of-freedom model for a human balancing on a balance board (BB) was developed. Analysis of the model revealed the BoAs and the amplitude of the LCOs. Results show that physical parameters (time-delays and feedback control gains) have a large impact on the size of the BoA and the amplitude of the LCOs. Particularly, the size of the BoA increases when balancing on a rigid surface and decreases when either proprioceptive or combined visual and vestibular (V&V) feedback gain is too high. With respect to the LCOs, it is shown that they emerge from both the subcritical and supercritical HBs and increase their amplitudes as some parameters vary.
Numerical Study of Solid Particle Erosion in a Centrifugal Pump for Liquid–Solid Flow
Authors: Lai Fen , Wang Yu , EI-Shahat Saeed A. , Li Guojun , Zhu Xiangyuan
Published: April 2019

Solid particle erosion is a serious issue in centrifugal pumps that may result in economic losses. Erosion prediction in centrifugal pump is complex because the flow field inside it is three-dimensional (3D) unsteady and erosion can be affected by numerous factors. In this study, solid particle erosion of the entire centrifugal pump for liquid–solid flow is investigated numerically. Two-way coupled Eulerian–Lagrangian approach is adopted to calculate the liquid–solid interaction. The reflection model proposed by Grant and Tabakoff and the erosion model proposed by the Erosion/Corrosion Research Center are combined to calculate the erosion rate and predict the erosion pattern. Results show that for the baseline case, the inlet pipe is the least eroded component, whereas the impeller is the most eroded component. The highest average and maximum erosion rates occur at the hub of impeller. The most severe erosion region of a blade is the leading edge with a curvature angle that varies from 55 deg to 60 deg. The most severe erosion region of a volute is in the vicinity of a curvature angle of 270 deg. The impeller erosion pattern, especially the middle part of the hub and the vicinity of the blade pressure side, can be greatly influenced by operation parameters, such as flow rate, particle concentration, and particle size.
Isogeometric Optimal Design of Compliant Mechanisms Using Finite Deformation Curved Beam Built-Up Structures
Authors: Choi Myung-Jin , Cho Seonho
Published: April 2019

This paper presents a configuration and sizing design optimization method for large deformation planar compliant mechanisms, using a continuum-based adjoint design sensitivity analysis (DSA) approach for built-up structures. Under the total Lagrangian formulation, the Jaumann strain formulation using the discretization of the global displacement field is employed to account for the finite deformation of arbitrarily curved Kirchhoff beams. In multipatch models, a rotational junction continuity condition is imposed using penalty and Lagrange multiplier methods. The developed adjoint DSA method can handle nonconservative loading conditions, which lead to asymmetry of tangent operator. Performance measures are displacements and rotation angles, and neutral axis configuration and cross-sectional thickness are considered as design variables. Also, analytical design sensitivity expressions for the rotation continuity condition are derived. Various compliant mechanisms including path-generators and an angular rotator are synthesized to demonstrate the applicability of the proposed method.
Data-Driven Design Space Exploration and Exploitation for Design for Additive Manufacturing
Authors: Xiong Yi , Duong Pham Luu Trung , Wang Dong , Park Sang-In , Ge Qi , Raghavan Nagarajan , Rosen David W.
Published: April 2019

Recently, design for additive manufacturing has been proposed to maximize product performance through the rational and integrated design of the product, its materials, and their manufacturing processes. Searching design solutions in such a multidimensional design space is a challenging task. Notably, no existing design support method is both rapid and tailored to the design process. In this study, we propose a holistic approach that applies data-driven methods in design search and optimization at successive stages of a design process. More specifically, a two-step surrogate model-based design method is proposed for the embodiment and detailed design stages. The Bayesian network classifier is used as the reasoning framework to explore the design space in the embodiment design stage, while the Gaussian process regression model is used as the evaluation function for an optimization method to exploit the design space in detailed design. These models are constructed based on one dataset that is created by the Latin hypercube sampling method and then refined by the Markov Chain Monte Carlo sampling method. This cost-effective data-driven approach is demonstrated in the design of a customized ankle brace that has a tunable mechanical performance by using a highly stretchable design concept with tailored stiffnesses.
Damage and Springback Analysis of Two Typical Dented Pipelines With Different Parameters
Authors: Wu Ying , Li Jiacheng , Li Linya
Published: April 2019

During pipeline construction, the pipeline may be impacted by sharp rocks or excavators. To study the failure mechanism of the pipeline, the damage degree and springback rate of the pipelines with two typical dents (transverse and longitudinal) were analyzed in terms of various factors (indenter size, pipeline size and internal pressure, and dent depth). The results reveal the following: (1) when pipeline size and internal pressure are unchanged and indenter size is changed, the integral value I used to measure the damage degree of the dented pipeline increases with increasing dent depth. When the dent depth reaches a certain value, at the same dent depth, the smaller the indenter size, the larger the damage integral value; (2) when other parameters remain unchanged, the larger the pipeline size is, the larger is the damage integral value, and the larger the internal pressure is, the smaller is the damage integral value. (3) The curves for damage and springback for the two kinds of dents are basically similar. Generally, the maximum damage of the longitudinal dent is larger than that of the transverse dent. (4) By a combination of an orthogonal experimental design and a gray correlation degree calculation, for the damage integral value of the two typical dented pipelines, the order of importance of the influential factors was obtained. (5) Formulas for the damage integral value and influence factors were fit using a nonlinear regression method, which provides a reference for calculation of pipeline damage.
A Hybrid Tracked-Wheeled Multi-Directional Mobile Robot
Authors: Ben-Tzvi Pinhas , Saab Wael
Published: April 2019

This paper presents the novel design and integration of a mobile robot with multi-directional mobility capabilities enabled via a hybrid combination of tracks and wheels. Tracked and wheeled locomotion modes are independent from one another, and are cascaded along two orthogonal axes to provide multi-directional mobility. An actuated mechanism toggles between these two modes for optimal mobility under different surface-traction conditions, and further adds an additional translational axis of mobility. That is, the robot can move in the longitudinal direction via the tracks on rugged terrain for high traction, in the lateral direction via the wheels on smooth terrain for high-speed locomotion, and along the vertical axis via the translational joint. Additionally, the robot is capable of yaw axis mobility using differential drives in both tracked and wheeled modes of operation. The paper presents design and analysis of the proposed robot along with a dynamic stabilization algorithm to prevent the robot from tipping over while carrying an external payload on inclined surfaces. Experimental results using an integrated prototype demonstrate multi-directional capabilities of the mobile platform and the dynamic stability algorithm to stabilize the robot while carrying various external payloads on inclined surfaces measuring up to 2.5 kg and 10 deg, respectively.
Design and Analysis of Reconfigurable Deployable Polyhedral Mechanisms With Straight Elements
Authors: Li Ruiming , Sun Xuemin , Chen Yaqiong , Yao Yan-an , Ding Xilun
Published: April 2019

This paper presents the construction method of a family of reconfigurable deployable polyhedral mechanisms (RDPMs) based on straight elements. First, reconfigurable straight element (RSE) is designed from two aspects: two prismatic-revolute-revolute-prismatic mechanisms aspect and reconfigurable angulated element aspect, and the kinematics and multifurcation of RSE are investigated. Then reconfigurable multiple straight elements (RMSEs) with n pairs of straight elements are proposed, RMSEs can reach two different transition configurations, the constraint conditions of RMSEs at transition configuration I and transition configuration II are analyzed with all link lengths identified. Finally, two typical polyhedra are used as a basis to construct RDPMs to verify the feasibility of the proposed construction method. A combination of half platforms and whole platforms for the first time is used in the construction of RDPMs, and the obtained mechanisms can switch between two kinds of conventional deployment configurations (the Hoberman sphere motion configuration and radially reciprocating motion configuration) and their compound configurations.
Sticking probabilities of H2O and Al(CH3)3 during atomic layer deposition of Al2O3 extracted from their impact on film conformality
Authors: Arts Karsten , Vandalon Vincent , Puurunen Riikka L. , Utriainen Mikko , Gao Feng , Kessels Wilhelmus M. M. (Erwin) , Knoops Harm C. M.
Published: April 2019

The conformality of a film grown by atomic layer deposition (ALD) is strongly affected by the reactivities of the precursor and coreactant, which can be expressed in terms of their sticking probabilities toward the surface. We show that the leading front of the thickness profile in high-aspect-ratio structures gives direct information on the sticking probabilities of the reactants under most conditions. The slope of the front has been used to determine the sticking probabilities of Al(CH3)3 and H2O during ALD of Al2O3. The determined values are (0.5–2) × 10−3 for Al(CH3)3 and (0.8–2) × 10−4 for H2O at a set-point temperature of 275 °C, corresponding to an estimated substrate temperature of ∼220 °C. Additionally, the thickness profiles reveal soft-saturation behavior during the H2O step, most dominantly at reduced temperatures, which can limit the conformality of Al2O3 grown by ALD. This work thus provides insights regarding quantitative information on sticking probabilities and conformality during ALD, which is valuable for gaining a deeper understanding of ALD kinetics.
Scandium function in “scandate” thermionic cathodes: A microspot synchrotron radiation x-ray photoelectron spectroscopy study of co-adsorbed Ba-Sc-O on W(100)
Authors: Mroz Michael V. , Kordesch Martin E. , Sadowski Jerzy T.
Published: April 2019

The coadsorption of barium, scandium, and oxygen on W(100) was investigated with microspot synchrotron radiation x-ray photoelectron spectroscopy ( μ-SRXPS) in the emission microscope at the electron-spectro-microscopy beam line at the National Synchrotron Light Source II. The Ba-Sc-O-W(100) system is a model for “scandate” thermionic electron emitters. The barium 4d, tungsten 4f, and scandium 3p (Sc3p) levels were observed after metal deposition and adsorption of oxygen. The initial deposits of metallic scandium and barium were confirmed with μ-SRXPS. After oxygen adsorption, the Sc3p peaks shifted to higher binding energy (by >4 eV), indicating the formation of Sc2O3 or a related compound. After heating to 800 °C, the barium 4d peaks were no longer observed. The shifted Sc3p peak was also absent. The results indicate that scandium acts as a cleaning agent to remove oxygen from the tungsten surface. The oxidized scandium is removed by reaction with barium and desorption below 800 °C. The temperature of desorption indicates that scandium does not remain on the surface at a temperature where a contribution to the reduction of the surface barrier to electron emission could be expected.
Privacy in a corporative office
Authors: Beristain Sergio
Published: April 2019

A corporative headquarters were installed in three floors of a new ten story building, where all the needed spaces were properly distributed as requested by the customer, which included private offices, meeting rooms, open plan offices, etc., the former two were located in one end of the two highest floors chosen, away from the stairs and elevator. Within weeks after the inauguration of the venue, the company directives noticed that some key design and production information was being leaked somehow and were not able to find out the process, which was a major problem for the company. They requested a quick and efficient solution to this matter, because they could not stop their activities, and they were not willing to lose any more information.
Echoes from the ocean’s interior: High-frequency observations of ocean phenomena
Authors: Weber Thomas C. , Mayer Larry , Lyons Anthony P. , Loranger Scott , Padilla Alexandra M. , Weidner Elizabeth F.
Published: April 2019

Recent technological advances in high-frequency (>10 kHz) sonar transducers, sonar transceivers, and sonar design have been accompanied by increased capabilities for observing ocean phenomena. These advances include the high range resolution and frequency-domain target classification capabilities associated with wideband acoustic echo sounders, the long-range high-resolution synoptic imaging capabilities associated with multibeam echo sounders and synthetic aperture sonar, and an increased focus on sensor calibration for all systems. High-frequency sonars are increasingly being used to quantify ocean phenomena at scales ranging from sub-centimeter (e.g., individual gas bubbles) to 100s of km (e.g., internal waves) to several 10s of km (e.g., thermohaline staircases). In this talk, we highlight some of the ocean processes that we have been investigating using high-frequency sonar systems, typically involving the transport of hydrocarbons, heat, energy, and fresh water into and through the ocean, and some of the (many) acoustic challenges that must be overcome to continue to increase the value of these observations.
Low frequency acoustical scattering from dynamic schools of swim bladder fish
Authors: Donoso Luis , Feuillade Christopher
Published: April 2019

A time-domain computational model is used to describe the dynamic evolutions of fish schools. The individual and ensemble fish behaviors are governed by three radial parameters, representing attraction, orientation, and repulsion zones between fishes. Different combinations of these radii cause the schools to evolve into various discoid, swarming, parallelized, or toroidal geometric forms. A previously developed model [J. Acoust. Soc. Am. 99, 196–208 (1996)] is applied to study the variations in ensemble scattering from these school types for ensonification frequencies in the swim bladder resonance region, as a function of frequency and time, and predicts distinct characteristic features for the different school geometries. In particular, this work focuses on scattering from disk-shaped schools, by examining the computed resonance response for different school dimensions, packing density, and orientation, in order to identify specific features that are determinative for this type of arrangement. The ultimate goal of this work is to achieve a better understanding of the physical basis for variations in fish school scattering levels and to obtain a detailed statistical description of these objects. [Work supported by ONRG.]
Assessment of human diaphragm function by ultrasounds
Authors: Aliverti Andrea
Published: April 2019

Thoracic ultrasound can provide a non-invasive technique for human diaphragm functional assessment, which can be used as an alternative to traditional, more challenging, and uncomfortable methods, such as transdiaphragmatic pressure measurement, fluoroscopic sniff test, nerve conduction studies, and electromyography. The variables that can be assessed using ultrasounds are (1) the static measurement of the end-expiratory diaphragm thickness (Tdi), (2) the dynamic evaluation of the ratio of inspiratory to the expiratory diaphragm thicknesses, reported as the "thickening ratio" or "thickening fraction" (TF), and (3) the diaphragmatic excursion. The measurements of Tdi and TF are performed by placing a high-frequency linear probe at the level of the zone of apposition, while diaphragm excursion is measured using a curvilinear probe placed in the subcoastal region and recording diaphragm movements in the M-mode. Intra- and inter-observer reliabilities of the measurement of Tdi and TF are high, and ultrasound estimates of Tdi are correlated to direct anatomical measurements. Tdi can be used to monitor the evolution of diaphragm weakness. The reduced values of TF are associated with diaphragmatic paresis. Diaphragm excursion is sensitive to changes in the respiratory pattern, related to diaphragm’s volume generating capacity, and can be used to identify diaphragm weakness. In intubated patients, diaphragm excursion is related to weaning outcome.
Subjective and objective assessments of pediatric and neonatal hospital soundscapes
Authors: Hasegawa Yoshimi , Ryherd Erica E.
Published: April 2019

Existing literature reveals that overall noise levels in pediatric and neonatal hospital units are exceeding acceptable ranges and exhibiting persistent noise level fluctuations over time and location. Previous studies have also revealed insights into the subjective perception of noise and explored existing noise sources and their measured acoustical properties. However, less has been done regarding clear identification of hospital noise sources related to staff annoyance in addition to detailed, informative representations of the acoustical characteristics of hospital environments. This study utilizes two methods of unsupervised learning techniques— factor analysis and clustering analysis— to assess occupant perception alongside detailed noise level measurements. Data were collected in two pediatric and neonatal hospital units to provide informative representations of the existing acoustical environments. The factor analysis results show three inherent noise categories among the various noise sources in the hospitals. The subsequent multiple linear regression demonstrates potential negative impacts of those noise categories on occupants’ psychological responses. The clustering analysis results show some relevant parameters for classifying the noise levels into a number of distinct conditions related to the activity level. This study presents new methods for screening hospital acoustical environments and allows us to gain insight into problematic hospital noise and corresponding perception.
Ambient infrasound noise in urban environments
Authors: McComas Sarah , Hayward Chris , Simpson Christopher , Stump Brian W. , McKenna Mihan H.
Published: April 2019

Associated with the emerging use of infrasound at tactical ranges (less than 50 km in complicated terrain), there is an increased need to deploy infrasound arrays in urban environments near sources of interest in order to record small signals. Initial urban deployment research demonstrated successful monitoring of a single source within 1 km utilizing rooftop infrasound arrays. In order to understand the applicability of this technique for a broader range of sources, the impact of the urban array design on noise reduction and detection of signals of interest must be assessed. These source signals, recorded within an urban scenario, are embedded in a complicated ambient noise environment with multiple coherent clutter sources and an overall decrease in the signal-to-noise ratio. Understanding these ambient acoustic field characteristics requires deconvolving observed coherent signals from time-varying atmospheric effects for different levels of urbanization. This paper presents an initial approach to instrumenting the urban environment with consideration of wind filter effects and data analysis to estimate total ambient acoustic field for a subset of urban zones. This work then provides a definition of urbanization that can be related to the infrasound wavefield. Permission to publish was granted by the Director, Geotechnical and Structures Laboratory.
Dynamic reconfiguration of two-dimensional lattices with bistable springs
Authors: Meaud Julien
Published: April 2019

This study focuses on wave propagation and reconfiguration in two-dimensional square mass-spring lattices that include bistable springs. Due to the presence of directional and/or omnidirectional bandgaps in stable deformed configurations in which some of the bistable springs are in a deformed equilibrium, these lattices have the ability to serve as reconfigurable wave filters and wave guides. In this work, we study non-linear wave propagation in response to stimulus of large amplitude. Mechanical stimuli of large amplitudes have the capability of causing a dynamic reconfiguration of the lattice to a configuration of lower potential energy, which dramatically affect wave propagation. Using numerical simulations, the influence of the stimulus amplitude, duration, and location of the applied stimulus on the reconfiguration is analyzed. The ability to alter in a predictable manner wave propagation in these lattices offers new opportunities for tunable phononic crystals.
Vibration reduction for gravitational wave detectors
Authors: Frajuca Carlos , Bortoli Fabio D. , Magalhaes Nadja S.
Published: April 2019

ultimately vibration detectors. They transform the vibrations in space-time into electrical vibrations in the electronic components of the detector. In this work, it is shown that how undesirable vibration is reduced in some of these detectors, even when it is necessary, in order to increase the general sensitivity, to incorporate in such detectors devices that vibrate alone and may compromise the overall performance.
Topology optimization of origami-inspired reconfigurable frequency selective surfaces
Authors: Fuchi Kazuko , Gillman Andrew , Buskohl Philip , Pankonien Alexander
Published: April 2019

Fold-driven reconfigurable devices have a potential to expand functional spaces beyond traditional adaptive wave propagation strategies. In particular, designs inspired by the art of origami leverage the mathematics of origami to map designs defined on two-dimensional surfaces to complex three-dimensional shapes. The design space in this paradigm is vast, so a systematic method is needed to design a device that achieves its goal. In our initial effort, we surveyed electromagnetic wave propagation properties of foldable frequency selective surfaces (FSS) and foldable and deployable antennas based on various known origami designs to identify a number of working principles of functional tuning. We incorporated these findings in the implementation of a design method that finds an origami FSS pattern that achieves the desired frequency tuning. This method is adopted from density-based topology optimization, with a notion that anything functional could be described through a distribution of an effective density of the relevant material property. A substrate is “patterned” with foldable segments parameterized through torsional springs; electromagnetically relevant conductive patterns are described as predefined surfaces that remain unchanged. This talk will discuss the lessons learned from our investigations and remaining challenges of designing fold-driven reconfigurable devices for wave propagation control.
Dedicated signal processing for lung ultrasound imaging: Can we see what we hear?
Authors: Demi Libertario
Published: April 2019

The application of ultrasound imaging to the diagnosis and monitoring of the lung condition is nowadays receiving growing attention from both the clinical and technical world. The advantages of ultrasound are in fact numerous when compared to other imaging modalities such as CT: availability at patient site, low cost, real time, and safety. However, despite the vast amount of medical evidence showing how ultrasound can be used to gather diagnostic information, dedicated technical developments are still lacking. This leaves the clinitians with the only option of using standard ultrasound scanners and probes and consequently implies that decisions are often based on imaging artifacts. Standard ultrasound imaging is in fact based on the assumption that among the structures present in the field of view, only little variations in the speed-of sound are present. This is clearly not the case with the lung, due to the presence of air. In this talk, recently developed imaging modalities and signal processing techniques dedicated to the analysis of the lung response to ultrasound will be introduced and discussed. In vitro and clinical data will be presented which show how the study of the ultrasound spectral feature could lead to a quantitative ultrasound method dedicated to the lung.