bluuebunny/crossref_metadata_2025 huggingface dataset:
A Mixed Method Examination of Gender Differences in Perceptions of STEM among Iranian Americans
Authors: Folberg Abigail M. , Kaboli‐Nejad Sahra
Published: August 2020

Much of the research on gender differences in STEM pursuit has been conducted on predominantly White samples in the United States and Western Europe, where women are underrepresented in STEM. Little is known about the factors that influence STEM participation in cultures where women are overrepresented in STEM, as they are in Iran (Masood, 2006). Iranian American students (N = 92) completed measures of cultural orientation, agentic and communal goal orientations and affordances, and interest in STEM and responded to open ended questions regarding their choice of major and perceptions of STEM. Stronger orientation toward Iranian culture was associated with stronger perceptions that STEM careers afforded communal goals and greater interest in STEM among women (vs. men). Qualitative responses suggested that Iranian American students perceived STEM positively and perceived STEM as providing opportunities for agentic and communal goal fulfillment. Understanding the role of culture in perceptions of STEM is necessary to understand gender and ethnic group differences in STEM pursuit.
OsPIN9, an auxin efflux carrier, is required for the regulation of rice tiller bud outgrowth by ammonium
Authors: Hou Mengmeng , Luo Feifei , Wu Daxia , Zhang Xuhong , Lou Manman , Shen Defeng , Yan Ming , Mao Chuanzao , Fan Xiaorong , Xu Guohua , Zhang Yali
Published: August 2020

The degree of rice tillering is an important agronomic trait that can be markedly affected by nitrogen supply. However, less is known about how nitrogen‐regulated rice tillering is related to polar auxin transport.

Compared with nitrate, ammonium induced tiller development and was paralleled with increased 3H‐indole‐acetic acid (IAA) transport and greater auxin into the junctions. OsPIN9, an auxin efflux carrier, was selected as the candidate gene involved in ammonium‐regulated tillering based on GeneChip data.

Compared with wild‐type plants, ospin9 mutants had fewer tillers, and OsPIN9 overexpression increased the tiller number. Additionally, OsPIN9 was mainly expressed in vascular tissue of the junction and tiller buds, and encoded a membrane‐localised protein. Heterologous expression in Xenopus oocytes and yeast demonstrated that OsPIN9 is a functional auxin efflux transporter. More importantly, its RNA and protein levels were induced by ammonium but not by nitrate, and tiller numbers in mutants did not respond to nitrogen forms. Further advantages, including increased tiller number and grain yield, were observed in overexpression lines grown in the paddy field at a low‐nitrogen rate compared with at a high‐nitrogen rate.

Our data revealed that ammonium supply and an auxin efflux transporter co‐ordinately control tiller bud elongation in rice.
Evaluating the effect of biochar on salt leaching and nutrient retention of Yellow River Delta soil
Authors: Xiao Liang , Meng Fande
Published: August 2020

Biochar has the potential to decrease salinity and nutrient loss of saline soil. We investigated the effects of biochar amendment (0–10 g kg−1) on salinity of saline soil (2.8‰ salt) in NaCl leaching and nutrient retention by conducting column leaching experiments. The biochar was produced in situ from Salix fragilis L. via a fire‐water coupled process. The soil columns irrigated with 15 cm of water showed that biochar amendment (4 g kg−1) decreased the concentration Na+ by 25.55% in the first irrigation and to 60.30% for the second irrigation in sandy loam layer over the corresponding control (CK). Meanwhile, the sodium adsorption ratio (SAR) of soil after the first and second irrigation was 1.62 and 0.54, respectively, which were 15.2% and 49.5% lower than CK. The marked increase in saturated hydraulic conductivity (Ks) from 0.15 × 10–5 cm s−1 for CK to 0.39 × 10–5 cm s−1, following 4 g kg−1 of biochar addition, was conducive to salt leaching. Besides, biochar use (4 g kg−1) increased NH4+‐N and Olsen‐P by 63.63% and 62.50% over the CK, but accelerated NO3–‐N leaching. Since 15 cm hydrostatic pressure would result in salt accumulation of root zone, we would recommend using 4 g kg−1 of biochar, 30 cm of water to ease the problem of salt leaching from the surface horizon to the subsoil. This study would provide a guidance to remediate the saline soil in the Yellow River Delta by judicious application of biochar and irrigation.
Genetic evidence for an inhibitory role of tomosyn in insulin‐stimulated GLUT4 exocytosis
Authors: Wang Shifeng , Liu Yinghui , Crisman Lauren , Wan Chun , Miller Jessica , Yu Haijia , Shen Jingshi
Published: August 2020

Exocytosis is a vesicle fusion process driven by soluble N‐ethylmaleimide‐sensitive factor attachment protein receptors (SNAREs). A classic exocytic pathway is insulin‐stimulated translocation of the glucose transporter type 4 (GLUT4) from intracellular vesicles to the plasma membrane in adipocytes and skeletal muscles. The GLUT4 exocytic pathway plays a central role in maintaining blood glucose homeostasis and is compromised in insulin resistance and type 2 diabetes. A candidate regulator of GLUT4 exocytosis is tomosyn, a soluble protein expressed in adipocytes. Tomosyn directly binds to GLUT4 exocytic SNAREs in vitro but its role in GLUT4 exocytosis was unknown. In this work, we used CRISPR‐Cas9 genome editing to delete the two tomosyn‐encoding genes in adipocytes. We observed that both basal and insulin‐stimulated GLUT4 exocytosis was markedly elevated in the double knockout (DKO) cells. By contrast, adipocyte differentiation and insulin signaling remained intact in the DKO adipocytes. In a reconstituted liposome fusion assay, tomosyn inhibited all the SNARE complexes underlying GLUT4 exocytosis. The inhibitory activity of tomosyn was relieved by NSF and α‐SNAP, which act in concert to remove tomosyn from GLUT4 exocytic SNAREs. Together, these studies revealed an inhibitory role for tomosyn in insulin‐stimulated GLUT4 exocytosis in adipocytes. We suggest that tomosyn‐arrested SNAREs represent a reservoir of fusion capacity that could be harnessed to treat patients with insulin resistance and type 2 diabetes.
Improved biodegradation of pharmaceuticals after mild photocatalytic pretreatment
Authors: de Wilt Arnoud , Arlos Maricor J. , Servos Mark R. , Rijnaarts Huub H. M. , Langenhoff Alette A. M. , Parker Wayne J.
Published: August 2020

The combination of photocatalysis and biodegradation was investigated for the removal of nine selected pharmaceuticals as a means to reduce loadings into the environment. The combined process, consisting of a resource‐efficient mild photocatalysis and a subsequent biological treatment, was compared to single processes of intensive photocatalysis and biological treatment. The UV‐TiO2 based photocatalysis effectively removed atorvastatin, atenolol and fluoxetine (>80%). Biological treatment after mild photocatalytic pretreatment removed diclofenac effectively (>99%), while it persisted during the single biological treatment (<50%). Moreover, the biodegradation of atorvastatin, caffeine, gemfibrozil and ibuprofen was enhanced after mild photocatalytic pretreatment compared to biological treatment alone. The enhanced biodegradation of these pharmaceuticals appeared to be triggered by the biodegradation of photocatalytic products. Mild photocatalysis followed by biological treatment is an effective and resource‐efficient combination for pharmaceutical removal that could substantially reduce the loading of pharmaceuticals into the environment.
Hypothalamic–vagal oxytocinergic neurocircuitry modulates gastric emptying and motility following stress
Authors: Jiang Yanyan , Travagli R. Alberto
Published: August 2020

Key points

Stress triggers and exacerbates the symptoms of functional gastrointestinal disorders, such as delayed gastric emptying and impaired gastric motility.

Understanding the mechanisms by which the neural circuits, impaired by stress, are restored may help to identify potential targets for more effective therapeutic interventions.

Oxytocin administration or release ameliorates the stress‐induced delayed gastric emptying and motility. However, is it unclear whether the effects are mediated via the hypothalamic‐pituitary‐adrenocortical axis or the oxytocinergic projections from the paraventricular nucleus of the hypothalamus to brainstem neurones of the dorsal vagal complex.

We used Cre‐inducible designer receptors exclusively activated by designer drugs to demonstrate the fundamental role of the oxytocinergic hypothalamic–vagal projections in the gastric adaptation to stress.

Stress triggers and exacerbates the symptoms of functional gastrointestinal (GI) disorders, such as delayed gastric emptying and impaired gastric motility. The prototypical anti‐stress hormone, oxytocin (OXT), plays a major role in the modulation of gastric emptying and motility following stress. It is not clear, however, whether the amelioration of dysregulated GI functions by OXT is mediated via an effect on the hypothalamic‐pituitary‐adrenocortical axis or the oxytocinergic projections from the paraventricular nucleus of the hypothalamus (PVN) to neurones of the dorsal vagal complex (DVC). In the present study we tested the hypothesis that the activity of hypothalamic–vagal oxytocinergic neurocircuits plays a major role in the gastric adaptation to stress. Cre‐inducible designer receptors exclusively activated by designer drugs (DREADDs) were injected into the DVC of rats and retrogradely transported to allow selective expression in OXT neurones in the PVN. Following acute stress and either chronic heterotypic (CHe) or chronic homotypic (CHo) stress, gastric emptying was assessed via the [13C]‐octanoic acid breath test, and gastric tone and motility were assessed via strain gauges sewn on the surface of the stomach. Activation of the hypothalamic–vagal oxytocinergic neurocircuitry, by DREADD agonist clozapine‐N‐oxide (CNO), prevented the delayed gastric emptying observed following acute or CHe stress, and 4th ventricular administration of CNO increased gastric tone and motility. Conversely, CNO‐mediated inhibition of the hypothalamic–vagal oxytocinergic neurocircuitry prevented the CHo‐induced adaptation in gastric emptying, and an increase in gastric tone and motility. Taken together, the data support the hypothesis that hypothalamic–vagal oxytocinergic neurocircuits play a major role in the modulation of gastric emptying and motility following stress.
Experimental and Numerical Quantification of the Aerodynamic Damping of a Turbine Blisk
Authors: Meinzer Christopher E. , Seume Joerg R.
Published: August 2020

Aerodynamic damping is the key parameter to determine the stability of vibrating blade rows in turbomachinery design. Both, the assessments of flutter and forced response vibrations need an accurate estimate of the aerodynamic damping to reduce the risk of high cycle fatigue that may result in blade loss. However, only very few attempts have been made to measure the aerodynamic damping of rotating blade rows experimentally under realistic operating conditions, but always with friction damping being present. This study closes the gap by providing an experiment in which a turbine blisk is used to eliminate friction damping at the blade roots and thereby isolate aerodynamic damping. The blades are excited acoustically and the resulting nodal diameter modes are measured using an optical tip-timing system in order to realize a fully non-intrusive setup. The measured vibration data are fitted to a single degree-of-freedom model (SDOF) to determine the aerodynamic damping. The results are in good accordance with the time-linearized CFD simulation. It is observed, however, that not only the sweep rate of the acoustic excitation but also the variation of the rotational frequency during the sweep excitation, and the excitation frequency influence the apparent damping.
Inextensibility and Its Effect on the Number of Equilibria of Shallow Buckled Beams
Authors: Harvey Philip S. , Wiebe Richard , Cain Thomas M. N.
Published: August 2020

A buckled beam with shallow rise under lateral constraint is considered. The initial rise results from a prescribed end displacement. The beam is modeled as inextensible, and analytical solutions of the equilibria are obtained from a constrained energy minimization problem. For simplicity, the results are derived for the archetypal beam with pinned ends. It is found that there are an infinite number of zero lateral-load equilibria, each corresponding to an Euler buckling mode. A numerical model is used to verify the accuracy of the model and also to explore the effects of extensibility.
Energy Absorption of All-Metallic Corrugated Sandwich Cylindrical Shells Subjected to Axial Compression
Authors: Su Pengbo , Han Bin , Yang Mao , Zhao Zhongnan , Li Feihao , Zhang Qi , Zhang Qiancheng , Lu Tian Jian
Published: August 2020

The energy adsorption properties of all-metallic corrugated sandwich cylindrical shells (CSCSs) subjected to axial compression loading were investigated by the method combining experiments, finite element (FE) simulations, and theoretical analysis. CSCS specimens manufactured using two different methods, i.e., high-speed wire-cut electric discharge machining (HSWEDM) and extrusion, were tested under axial compression. While specimens fabricated separately by HSWEDM and extrusion both exhibited a stable crushing behavior, the extruded ones were much more applicable as lightweight energy absorbers because of their good energy absorption capacity, repeatability, and low cost. The numerically simulated force–displacement curve and the corresponding deformation morphologies of the CSCS compared well with those obtained from experiments. The specific folding deformation mode was revealed from both experiments and simulations. Subsequently, based upon the mode of folding deformation, a theoretical model was established to predict the mean crushing force of the CSCS construction. It was demonstrated that CSCSs with more corrugated units, smaller value of tc/tf and W/Ro could dissipate more impact energy. Such sandwich cylindrical shells exhibited better energy absorption than monolithic cylindrical shells, with an increase of at least 30%. Ultimately, the dynamic effect under the impact load was further evaluated. The dynamic amplification coefficient of CSCS decreased with the increase of the wall thickness.
Fast and Accurate Analysis of Steam Condensing Flows Using Ideal Gas Equation
Authors: Kim Changhyun , Park JaeHyeon , Baek Jehyun
Published: August 2020

When the steam is used in fluid machinery, the phase-transition can occur and it affects not only the flow fields but also the machine performance. Therefore, to achieve accurate prediction on steam condensing flow using computational fluid dynamics, the phase-transition phenomena should be considered and the proper model which can reflect the non-equilibrium characterisic is required. In the previous study of us, a non-equilibrium condensation model was implemented in T-flow, and several cases on nozzles and cascades were under the consideration. The model showed quite good predictions on the pressure variations including condensation shock. However, the pressure discrepancies in downstream regions were found in all nozzle cases, and the use of ideal gas law as equation of state seemed to be responsible for them. Therefore, IAPWS-95 or IF97 are usually adopted for wet-steam codes, but it entails highly increased computational costs. In this study, the wet-steam model is modified to ensure the accuracy of pressure in nozzle’s downstream region while maintaining the usage of ideal gas equation, which has a benefit to solve the problem quickly. The numerical results of the nozzles are compared with those of the previous wet-steam model, and the results of equilibrium condensation model are also appended. As a result, the accurate predictions are feasible by using the modified non-equilibrium condensation model. In addition, the corrections on liquid surface tension and droplet growth rate are carried out for underestimated droplet sizes and enthalpy, entropy changes throughout the nozzles are investigated.
A Novel Two-Stage Constant Force Compliant Microgripper
Authors: Ye Tingting , Ling Jie , Kang Xi , Feng Zhao , Xiao Xiaohui
Published: August 2020

The manipulating objects of the micron scale are easily damaged, hence the microgrippers, the key components in micro manipulating systems, demand precise force control, plus miniaturized size. Consequently, the constant force microgrippers, generally lack the ability to fit different sizes. To avoid the overload damage, apply multi-size microparts and simplify the control method, a novel two-stage compliant constant force microgripper is proposed in this paper. Based on the negative stiffness effect, this gripper is connected in parallel with a two-stage negative stiffness module and a positive stiffness module. Then, the elliptic integral method and the pseudo-rigid-body method are both employed to derive the kinetostatic and dynamic performances. Finally, the analytical results are validated. It is observed that two-stage constant forces of 1.33 N in 305.6 μm and 1.11 N in 330.8 μm are acquired.
Assessing Lifecycle Value Using Object-Based Modeling by Incorporating Excess and Changeability
Authors: Long Daniel , Ferguson Scott
Published: August 2020

Prior research suggests that excess (purposeful inclusion of margin beyond what is required for known system uncertainties) can limit change propagation and reduce system modifications. Reducing change costs increases system flexibility, permitting adaptions that satisfy uncertain future requirements. The benefits of excess, however, must be traded against higher costs of the initial system and likely performance decreases. Assessing the benefits and costs of excess requires evaluating what forms, locations, and magnitudes of excess inclusion are optimal. This paper improves the state-of-the-art in two ways. First, prior research has generally assessed excess in system-level properties (aggregating component properties into a single metric). The approach presented in this paper extends excess assessment to the component level so that the effects of excess on change propagation may be explicitly captured. Second, this approach holistically assesses the value of excess by evaluating both its costs and benefits. The approach borrows from Decision-Based Design and Model Based System Engineering (MBSE) in creating a generic modeling method capable of excess valuation. A desktop computer example is used for demonstrating how excess is valued in a system and the potential gains associated with excess inclusion when mining cryptocurrency. A single component optimization of the power supply capacity for the desktop is assessed to be 750 W, which balances the initial cost against the future flexibility. A system-level optimization then demonstrates the identification of critical change propagation pathways and illuminates both where and how excess may be included to inhibit change propagation. This key component was identified as the motherboard-central processing unit (CPU) slot in the tested systems.
Integrating Sequence Learning and Game Theory to Predict Design Decisions Under Competition
Authors: Bayrak Alparslan Emrah , Sha Zhenghui
Published: August 2020

Design can be viewed as a sequential and iterative search process. Fundamental understanding and computational modeling of human sequential design decisions are essential for developing new methods in design automation and human–AI collaboration. This paper presents an approach for predicting designers’ future search behaviors in a sequential design process under an unknown objective function by combining sequence learning with game theory. While the majority of existing studies focus on analyzing sequential design decisions from the descriptive and prescriptive point of view, this study is motivated to develop a predictive framework. We use data containing designers’ actual sequential search decisions under competition collected from a black-box function optimization game developed previously. We integrate the long short-term memory networks with the Delta method to predict the next sampling point with a distribution, and combine this model with a non-cooperative game to predict whether a designer will stop searching the design space or not based on their belief of the opponent’s best design. In the function optimization game, the proposed model accurately predicts 82% of the next design variable values and 92% of the next function values in the test data with an upper and lower bound, suggesting that a long short-term memory network can effectively predict the next design decisions based on their past decisions. Further, the game-theoretic model predicts that 60.8% of the participants stop searching for designs sooner than they actually do while accurately predicting when the remaining 39.2% of the participants stop. These results suggest that a majority of the designers show a strong tendency to overestimate their opponents’ performance, leading them to spend more on searching for better designs than they would have, had they known their opponents’ actual performance.
Design and Control of a Robotic Steering Mechanism for Electrophysiological Catheters
Authors: Lee Hoyul , Hu Zhenkai , Moon Youngjin , Kim Young-Hak , Nam Gi-Byoung , Choi Jaesoon
Published: August 2020

This paper proposes a catheter robot system for cardiac ablation therapy. The robot mechanism for actuating the catheter and the control methods of the catheter tip position will be suggested. The robot system consists of a front module and a handle-control module. The front module is a dual-gripper mechanism for inserting and rotating the catheter without slip between the catheter and gripper, and the handle-control module is for controlling the knob for the bending motion of the catheter. The proposed dual-gripper mechanism has the advantage of large contact surface between the grippers and the catheter, like the human finger, allowing it to form a stable grip of the catheter. However, for continuous insertion, the grippers should be controlled interactively. To achieve this, we explain the motion-planning and trajectory-generation methods. Moreover, we propose a control method that can intuitively control the position of the catheter using a mapping system as manual work. We explain the method of updating the Jacobian model in real time using two position sensors attached to the catheter. Finally, we show the simulation and experimental results to confirm the proposed mechanism and control methods useful for controlling the catheter
A Review on the Performance, Combustion, and Emission Characteristics of Spark-Ignition Engine Fueled With 2,5-Dimethylfuran Compared to Ethanol and Gasoline
Authors: Nguyen Danh Chan , Hoang Anh Tuan , Tran Quang Vinh , Hadiyanto Hadiyanto , Wattanavichien Kanit , Pham Van Viet
Published: August 2020

Currently, the supply of diminishing fossil fuel reserves, and the rise in challenges in environmental, political and economic consequences have caused the great concerns in the development of modern society; these have forced the policy-makers and researchers to look for the renewable and green energy sources. Deemed as a promising renewable alternative to traditional fossil fuels, 2,5-dimethylfuran (DMF, chemical formula C6H8O)—a derivative of furan—has the potential to relieve the growing shortage of fossil fuels while satisfying the increase in global energy demand and minimizing the adverse effects of climate change. DMF can be used as a clean source of liquid transportation biofuel given the fact that it is directly obtained from biomass-derived carbohydrates. In reviewing current DMF production methods, this review paper analyzes and presents the comparison of catalytic performance in the conversion of biomass into DMF. In addition, the applicability of DMF in spark-ignition (SI) engines is thoroughly analyzed based on the spray and flame, combustion, performance, and emission characteristics of SI engines running on DMF compared with ethanol and gasoline. More interestingly, the knocking, lubrication, and wear characteristics in SI engines fueled with DMF are also evaluated and discussed. Nonetheless, further investigation on optimization strategies on DMF production process should be conducted prior to the initiation of large-scale commercialization as well as the application of DMF to real-world SI engines.
Theoretical and Experimental Studies of Internal Cuttings Removal Bit
Authors: Cao Tong , Yu Kaian , Li Wenxing , Chen Xuyue , Zhu Hongwu
Published: August 2020

The oil and gas exploration without rig (also known as badger exploration) is a novel exploration technology that removes the need for fixed rig drilling, bringing with it the promise of huge savings in terms of time and money and its low impact on the environment. The implementation of this technology is an autonomous exploration tool, which can drill into rock using an electrically powered bit to loosen and crush the formation ahead of it, and crushed cuttings is moved through the device and deposited in the space behind it. Because there is no drilling fluid in badger drilling, a new way of transporting cuttings is urgently needed. In this paper, a new kind of bit named internal cuttings removal (ICR) bit is developed for badger exploration, and it can not only drill rock but also collect and transport cuttings to the bit behind through the inner cavity of the bit. Compared with the common polycrystalline diamond compact (PDC) bit, the junk slots are removed, but the helical blades and screw conveyor are added on the ICR bit. Theoretically, the two effects of rotating helical blades on cuttings moving are studied, based on the conditions of low and high rotating speed, respectively. Moreover, the rate of cuttings removal of the ICR bit is given in formulas, and in order to ensure the cuttings is removed from bottomhole timely, and the maximum permissible rate of penetration (ROP) of the ICR bit is proposed. Finally, two samples of the ICR bit with different structural parameters were built and tested in dry and wet rock drilling experiments, and experimental results show that the ICR bit can achieve the expected goal of ICR, but wet cuttings has a significant influence on the performance of the ICR bit. By comparing the drilling results of two bits, it can be found that the concave blade surface, a small number of blades, and small inner cone angle have the positive effects on the cuttings removal of the ICR bit. The above work is helpful for the development and implementation of badger exploration technology.
Performance of a Natural Gas Solid Oxide Fuel Cell System With and Without Carbon Capture
Authors: Iyengar Arun K. S. , Koeppel Brian J. , Keairns Dale L. , Woods Mark C. , Hackett Gregory A. , Shultz Travis R.
Published: August 2020

The fuel cell program at the United States Department of Energy (DOE) National Energy Technology Laboratory (NETL) is focused on the development of low-cost, highly efficient, and reliable fossil-fuel-based solid oxide fuel cell (SOFC) power systems that can generate environmentally friendly electric power with at least 90% carbon capture. NETL’s SOFC technology development roadmap is aligned with near-term market opportunities in the distributed generation sector to validate and advance the technology while paving the way for utility-scale natural gas (NG)- and coal-derived synthesis gas-fueled applications via progressively larger system demonstrations. The present study represents a part of a series of system evaluations being carried out at NETL to aid in prioritizing technological advances along research pathways to the realization of utility-scale SOFC systems, a transformational goal of the fuel cell program. In particular, the system performance of utility-scale NG fuel cell (NGFC) systems with and without carbon dioxide (CO2) capture is presented. The NGFC system analyzed features an external auto-thermal reformer (ATR) feeding the fuel to the SOFC system consisting of planar anode-supported SOFC with separated anode and cathode off-gas streams. In systems with CO2 capture, an air separation unit (ASU) is used to provide the oxygen for the ATR and for the combustion of unutilized fuel in the SOFC anode exhaust along with a CO2 purification unit to provide a nearly pure CO2 stream suitable for transport for usage in enhanced oil recovery (EOR) operations or for storage in underground saline formations. Remaining thermal energy in the exhaust gases is recovered in a bottoming steam Rankine cycle while supplying any process heat requirements. A reduced order model (ROM) developed at the Pacific Northwest National Laboratory (PNNL) is used to predict the SOFC performance. The ROM, while being computationally effective for system studies, provides other detailed information about the state of the stack, such as the internal temperature gradient, generally not available from simple performance models often used to represent the SOFC. Such additional information can be important in system optimization studies to preclude operation under off-design conditions that can adversely impact overall system reliability. The NGFC system performance was analyzed by varying salient system parameters, including the percent of internal (to the SOFC module) NG reformation—ranging from 0 to 100%—fuel utilization, and current density. The impact of advances in underlying SOFC technology on electrical performance was also explored.
Metrics Matter: Accurately Defining Energy Efficiency in Desalination
Authors: Bouma Andrew T. , Swaminathan Jaichander , Lienhard John H.
Published: August 2020

Energy cost contributes a large portion of the overall cost of desalinated water. Improving the energy efficiency of desalination plants is therefore a primary design goal. However, accurately evaluating and comparing the energy consumption of desalination plants that use different forms and grades of energy is difficult, especially for power–water coproduction systems in which primary energy (PE) consumption leads to both salable electricity and potable water. The power plant converts PE into grades of thermal energy and electricity usable by the desalination plant. To fully capture the thermodynamic and economic cost of energy, and to fairly compare desalination systems that use different grades of input energy, we must compare energy consumption not at the point where energy enters the desalination plant itself, but as PE consumption entering the power plant. This paper investigates a variety of metrics for comparing the energy and exergy consumption attributable to desalination in coproduction plants. Previous results have shown that reverse osmosis (RO) is approximately twice as efficient as multiple effect distillation (MED) on a PE basis. We then compare the PE consumption of MED and RO from a thermoeconomic perspective. The entropy generation at the RO membrane and in the MED effects are derived in similar terms, which enables a comparison of the overall heat transfer coefficient in an MED system to the permeability of an RO membrane. RO outperforms MED in energy efficiency because of a balance of material costs, transport coefficients, and cost of energy.
Analytical Modeling for Vapor Condensation in the Presence of Noncondensable Gas and Experimental Validation
Authors: Zhang Wei , Wang Suilin , Lianbo Mu
Published: August 2020

The sensible and latent heat transfer are two essential considerations in investigating vapor condensation in the presence of noncondensable gases. In this paper, a new model for filmwise condensation heat transfer was developed using similarity-based solution. The expression of gas–liquid interfacial temperature, film thickness, and heat transfer coefficient were derived and calculated, respectively. The analytical results showed that the temperature difference between gas–liquid interfacial and cooling surface is decreased as there is an increase in cooling surface temperature. In addition, the forced-convective condensation heat transfer and film thickness on the vertical surface were experimentally carried out. The proportion of latent heat is 62–67% and relatively larger than sensible heat in the range of wall temperature (17–32.5 °C). The experimental film thickness is less than analytical film thickness by 2–10%. It is because that the liquid film may evaporate back to water vapor in the neighboring wall area due to high temperature of flue gas. Further, a new nondimensional correlation of condensation heat transfer of flue gas is fitted with Nu = 0.62Re0.5Ja0.67 and applicable range is Re = 1000–2500, Ja = 1.7–4.4. The fitting shows a good agreement between experimental and correlated values except some points in the low Nu number. The model proposed is applicable to predict the temperature and velocity distribution for condensation heat and mass transfer of multicomponent gases.
Numerical Finger Kinematic Models Derived From Virtual Grasping of Various Cylindrical Objects With the Family of Conic Sections
Authors: Won Jong-Seob , Langari Reza , Robson Nina
Published: August 2020

In this study, a numerical framework for joint rotation configuration models of a finger is proposed. The basic idea is to replicate the finger’s geometric posture observed when the human hand grasps a cylindrical object with various cross sections. In the model development, objects with the cross section adopted from the curves of order two (the family of conic sections) are taken into consideration to realize various finger postures. In addition, four different grasp styles, which simulate the individual-specific contact pattern between the surfaces of object and finger, are modeled and applied for the formulation of numerical models. An idea on how to change flexion/extension patterns in the middle of excursion of movement is proposed and discussed. Series of numerical studies have been conducted and analyzed to evaluate the proposed models. From the results, one can see the models’ feasibility and viability as a solution to describing finger’s flexion/extension movements (FEMs) for grasping patterns.
Influence of Working Fluid on a Novel Solar Pond Coil
Authors: Yakubu M. , Shuja S. Z. , Yilbas B. S. , Al-Qahtani M.
Published: August 2020

A design configuration and selection of working fluid for solar absorption remain critical for high performance of energy harvesting process in solar pond. In this study, heating and pressure loss characteristics in a novel designed spiral-coil geometry pertinent to salt-gradient solar pond (SGSP) is examined and the thermal performance of nanofluids in the coil is assessed. Nanofluids possessing graphene, functionalized graphene nanoplatelet (fGnP), and graphene oxide (GO) at 0.06% volume concentration are considered as the working fluids in the system. In order to achieve a novel design of a spiral coil, the circular cross-sectional geometries with aspect ratios (AR) of 0.5, 1, and 2 are incorporated in the analysis. The selection of the aspect ratios of 0.5, 1, and 2 results in elliptic, circular, and oval cross sections of the coil, respectively. The findings reveal that heat transfer enhances and pressure loss reduces via increasing the mass flowrate. This is due to the formation of a stable secondary flow which causes mixing enhancement while shortening the thermal entry length. Circular and elliptic cross sections resulted in the maximum and the smallest normalized average Nusselt numbers, respectively, for low rates of flow. This is because of thermal resistance created under the large surface area-to-volume ratio; however, this effect varnishes for high mass flowrates. Graphene oxide and functionalized graphene nanoplatelet have the highest and the lowest normalized average pressure drops, respectively, for all flow rates.
Data-Driven Additive Manufacturing Constraints for Topology Optimization
Authors: Weiss Benjamin M. , Hamel Joshua M. , Ganter Mark A. , Storti Duane W.
Published: August 2020

The topology optimization (TO) of structures to be produced using additive manufacturing (AM) is explored using a data-driven constraint function that predicts the minimum producible size of small features in different shapes and orientations. This shape- and orientation-dependent manufacturing constraint, derived from experimental data, is implemented within a TO framework using a modified version of the moving morphable components (MMC) approach. Because the analytic constraint function is fully differentiable, gradient-based optimization can be used. The MMC approach is extended in this work to include a “bootstrapping” step, which provides initial component layouts to the MMC algorithm based on intermediate solid isotropic material with penalization (SIMP) topology optimization results. This “bootstrapping” approach improves convergence compared with reference MMC implementations. Results from two compliance design optimization example problems demonstrate the successful integration of the manufacturability constraint in the MMC approach, and the optimal designs produced show minor changes in topology and shape compared to designs produced using fixed-radius filters in the traditional SIMP approach. The use of this data-driven manufacturability constraint makes it possible to take better advantage of the achievable complexity in additive manufacturing processes, while resulting in typical penalties to the design objective function of around only 2% when compared with the unconstrained case.
Studies on the Influence of Stirrer Blade Design on the Microstructure and Mechanical Properties of a Novel Aluminum Metal Matrix Composite
Authors: Krishnan Pradeep Kumar , Arunachalam Ramanathan , Husain Afzal , Al-Maharbi Majid
Published: August 2020

In the present work, the influence of stirrer blade design on the dispersion of reinforcement particles in the aluminum metal matrix was studied extensively through experiments and also simulated them using the computational fluid dynamics (CFD) method. The microstructure and mechanical properties of the produced metal matrix composites (MMCs) were studied. The analysis of the microstructure was performed using an optical microscope to visualize the reinforcement distribution and binding within the matrix. Further, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were used to characterize the MMCs. The experimental density was assessed using the Archimedes method, and the theoretical density was determined using the mixture law to determine the percentage of porosity in the MMCs. Hardness, compression, and tensile testing were performed on the produced samples. A three-dimensional computational method was used to predict the flow field of aluminum melt and study the influence of the blade design on the distribution of the reinforcement. Experimental results validated the CFD recommendation on the blade design. The CFD recommendation was based on the structure, power number, and the number of blades, and accordingly, the four-blade flat stirrer (B4) design was the best. The experimental results also corroborated the CFD recommendation with the four-blade flat stirrer design achieving the highest compressive strength (642 MPa), highest hardness (45 HRB), and highest tensile strength (206 MPa) among the five different blade designs investigated.
Effect of Mechanical Properties on the Dynamics of Self-Oscillating Synthetic Vocal Folds
Authors: Burks Garret , Singh Manjot , De Vita Raffaella , Johnson Blake , Leonessa Alexander
Published: August 2020

This study focuses on the measured changes in dynamic behavior exhibited by eight synthetic vocal fold models with varying mechanical properties. Uniaxial tensile testing was conducted to determine changes in mechanical properties between materials made from silicone rubber and polydimethylsiloxane with varying mixing ratios. The results of the mechanical testing showed that the elastic modulus, E, varied from 20.6 to 437.4 kPa, the measured Poisson ratios, ν, spanned the range of 0.43–0.48, and the density, ρVF, varied from 0.86 to 1.02 g/cm3 across the eight samples. Vocal fold models were dynamically tested using a custom-built experimental setup that supplied a heated and humidified airflow to the synthetic vocal folds. The resulting sounds were recorded and analyzed to identify the change in fundamental frequency which spanned 66.8 to 342.6 Hz across the eight samples. In addition, a mathematical aeroelastic model of phonation was implemented to further investigate the relationship between the mechanical properties and phonation frequency. Finally, a proof-of-concept magnetic actuation method was demonstrated using magnetic elastomers to deform the synthetic vocal folds through the use of an electromagnet.
A Novel Virus Alters Gene Expression and Vacuolar Morphology in
Malassezia
Cells and Induces a TLR3-Mediated Inflammatory Immune Response
Authors: Park Minji , Cho Yong-Joon , Kim Donggyu , Yang Chul-Su , Lee Shi Mun , Dawson Thomas L. , Nakamizo Satoshi , Kabashima Kenji , Lee Yang Won , Jung Won Hee
Published: August 2020

Malassezia
is the most dominant fungal genus on the human skin surface and is associated with various skin diseases including dandruff and seborrheic dermatitis. Among
Malassezia
species,
Malassezia restricta
is the most widely observed species on the human skin. In the current study, we identified a novel dsRNA virus, named MrV40, in
M. restricta
and characterized the sequence and structure of the viral genome along with an independent satellite dsRNA viral segment. Moreover, expression of genes involved in ribosomal synthesis and programmed cell death was altered, indicating that virus infection affected the physiology of the fungal host cells. Our data also showed that the viral nucleic acid from MrV40 induces a TLR3-mediated inflammatory immune response in bone marrow-derived dendritic cells, indicating that a viral element likely contributes to the pathogenicity of
Malassezia
. This is the first study to identify and characterize a novel mycovirus in
Malassezia
.
RRE-Finder: a Genome-Mining Tool for Class-Independent RiPP Discovery
Authors: Kloosterman Alexander M. , Shelton Kyle E. , van Wezel Gilles P. , Medema Marnix H. , Mitchell Douglas A.
Published: August 2020

Bioinformatics-powered discovery of novel ribosomal natural products (RiPPs) has historically been hindered by the lack of a common genetic feature across RiPP classes. Herein, we introduce RRE-Finder, a method for identifying RRE domains, which are present in a majority of prokaryotic RiPP biosynthetic gene clusters (BGCs). RRE-Finder identifies RRE domains 3,000 times faster than current methods, which rely on time-consuming secondary structure prediction. Depending on user goals, RRE-Finder can operate in precision mode to accurately identify RREs present in known RiPP classes or in exploratory mode to assist with novel RiPP discovery. Employing RRE-Finder on the UniProtKB database revealed several high-confidence RREs in novel RiPP-like clusters, suggesting that many new RiPP classes remain to be discovered.
Injuries and illnesses among competitive Norwegian rhythmic gymnasts during preseason: a prospective cohort study of prevalence, incidence and risk factors
Authors: Gram Marte Charlotte Dobbertin , Clarsen Benjamin , Bø Kari
Published: August 2020

Objectives

Rhythmic gymnastics is an Olympic sport that demands high training volume from early age. We investigated the extent of, and risk factors for, injuries among competitive Norwegian rhythmic gymnasts.

Methods

One hundred and seven of 133 (80.5%) female rhythmic gymnasts (mean age: 14.5 years (SD 1.6), mean body mass index: 18.9 (SD 2.2)) participated. All gymnasts completed a baseline questionnaire and the ‘Triad-Specific Self-Report Questionnaire’. Injuries, illnesses and training hours were recorded prospectively for 15 weeks during preseason using the ‘Oslo Sports Trauma Research Center Questionnaire on Health Problems’ (OSTRC-H2).

Results

Response rate to OSTRC-H2 was 97%. Mean overuse and acute injury prevalence were 37% (95% CI: 36% to 39%) and 5% (95% CI: 4% to 6%), respectively. Incidence was 4.2 overuse injuries (95% CI: 3.6 to 4.9) and 1.0 acute injuries (95% CI: 0.5 to 1.6) per gymnast per year. Overuse injuries in knees, lower back and hip/groin represented the greatest burdens. Previous injury increased the odds of injury (OR 30.38, (95% CI: 5.04 to 183.25)), while increased age (OR 0.61 per year, (95% CI: 0.39 to 0.97)) and presence of menarche (OR: 0.20, (95% CI: 0.06 to 0.71)) reduced the odds of all injuries and substantial injuries, respectively.

Conclusions

Overuse injuries were common among Norwegian rhythmic gymnasts. Younger gymnasts had higher all-injury risk. Gymnasts who were not menstruating had higher substantial injury risk. Injury prevention interventions should start at an early age and focus on preventing knee, lower back and hip/groin injuries.
Comparing negative health indicators in male and female veterans with the Canadian general population
Authors: Hall Amy L , Sweet J , Tweel M , MacLean M B
Published: August 2020

Introduction

Sex-based information on differences between Canadian veterans and the general population is important to understand veterans’ unique health needs and identify areas requiring further research. This study compared various health indicators in male and female veterans with their Canadian counterparts.

Methods

Health indicators for recent-era Regular Force veterans (released between 1998 and 2015) were obtained from the 2016 Life After Service Survey and compared with the general population in the 2015–16 Canadian Community Health Survey using a cross-sectional approach. Age-adjusted rates and 95% CIs were calculated for males and females separately.

Results

Compared with Canadians, veterans (both sexes) reported higher prevalence of fair or poor health and mental health, needing help with one or more activity of daily living, lifetime suicidal ideation and being diagnosed with mood and anxiety disorders, post-traumatic stress disorder, migraines, back problems, chronic pain, arthritis, ever having cancer, hearing problems, chronic pain and gastrointestinal problems. A higher prevalence of cardiovascular disease (all types) and high blood pressure was observed in male veterans compared with their Canadian counterparts. Within veterans only, males reported a higher prevalence of diagnosed hearing problems and cardiovascular disease compared with females; conversely females reported a higher prevalence of diagnosed migraines, mood, anxiety and gastrointestinal disorders, and needing help with activities of daily living. These sex differences are similar to the Canadian general population. Some similarities in reporting prevalence between male and female veterans (eg, fair or poor mental health, lifetime suicidal ideation, arthritis, asthma, lifetime cancer incidence, chronic pain and diabetes) were not observed in other Canadians.

Conclusion

Male and female veterans differed from comparable Canadians, and from each other, in various areas of health. Further research is needed to explore these findings, and veteran-based policies and services should consider sex differences.