bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of dietary fibre level and body weight of pigs on nutrient digestibility and available energy in high‐fibre diet based on wheat bran or sunflower meal
Authors: Lyu Zhiqian , Zang Jianjun , Lai Changhua , Li Ping , Ma Dongli , Zhao Jinbiao , Zhang Shuai , Huang Chengfei
Published: September 2019

The objectives of this study were (a) to investigate the effect of body weight (BW) on available energy in fibre‐rich diets containing two NDF levels; and (b) to evaluate the effect of fibre type and NDF level on AA digestibility. In Exp. 1, barrows (24 at 33.4 ± 1.1 kg; 24 at 86.8 ± 3.3 kg) were randomly allotted to 4 diets containing a high protein basal (HPB), a low protein basal (LPB), 70% HPB + 30% wheat bran (WB) (HPB‐WB) and 70% LPB + 30% sunflower meal (SFM) (LPB‐SFM). In Exp. 2, barrows (24 at 33.5 ± 1.8 kg; 24 at 87.0 ± 3.8 kg) were randomly allotted to 4 diets containing no SFM with 12% NDF (SFM0LF), no SFM with 16% NDF (SFM0HF), 24% SFM with 12% NDF (SFM24LF) and 24% SFM with 16% NDF (SFM24HF). In Exp. 3, twelve barrows (35.5 ± 3.4 kg) fitted with T‐cannulas were allotted to two 6 × 4 Youden square design with 6 diets (4 same diets as in Exp. 2 and 2 nitrogen‐free diets). The concentration of DE, ME and ATTD of GE, CP, NDF and ADF in diets was greater (p < .01) when fed to 90 kg pigs compared with 30 kg pigs. The ME in ingredients was not affected by BW. The ATTD of NDF was negatively correlated with the CF (r = −.98; p < .01), ADF (r = −.99; p < .01) and ADL content (r = −.96; p < .01). The ME of diets was negatively correlated with the ATTD of CF (r = −.98; p < .01). The addition of SFM increased the standardized ileal digestibility (SID) of Met (p < .05). In conclusion, diets rich in fibre had different nutritional values at different pig weight stages. The AA digestibility depends mainly on chemical composition of diets.
A wall with integrity: surveillance and maintenance of the plant cell wall under stress
Authors: Rui Yue , Dinneny José R.
Published: September 2019

The structural and functional integrity of the cell wall needs to be constantly monitored and fine‐tuned to allow for growth while preventing mechanical failure. Many studies have advanced our understanding of the pathways that contribute to cell wall biosynthesis and how these pathways are regulated by external and internal cues. Recent evidence also supports a model in which certain aspects of the wall itself may act as growth‐regulating signals. Molecular components of the signaling pathways that sense and maintain cell wall integrity have begun to be revealed, including signals arising in the wall, sensors that detect changes at the cell surface, and downstream signal transduction modules. Abiotic and biotic stress conditions provide new contexts for the study of cell wall integrity, but the nature and consequences of wall disruptions due to various stressors require further investigation. A deeper understanding of cell wall signaling will provide insights into the growth regulatory mechanisms that allow plants to survive in changing environments.
Effects of resveratrol supplementation on bone biomarkers: a systematic review and meta‐analysis
Authors: Asis Marzieh , Hemmati Niloufar , Moradi Sajjad , Nagulapalli Venkata Kalyan C. , Mohammadi Elham , Farzaei Mohammad Hosein , Bishayee Anupam
Published: September 2019

The current study presents a comprehensive systematic review and meta‐analysis of randomized controlled trials (RCTs) on resveratrol and bone health biomarkers. PubMed, Scopus, and Web of Science (until September 2018) were searched to identify the potential RCTs with information on resveratrol supplementation and bone metabolism biomarkers. Mean differences (MD) were analyzed using a random‐effects model. Pooling six RCTs (eight treatment arms with 264 subjects) together identified no significant reduction of serum Ca, osteocalcin, C‐terminal telopeptide of type I collagen, and procollagen I N‐terminal propeptide values after resveratrol supplementation over placebo treatment. However, a significant increase in serum alkaline phosphatase (ALP) (MD: 5.69 mg/mL, 95% CI: 3.58–7.80, I2 = 95.7%, P < 0.001) and bone alkaline phosphatase (BAP) (MD: 10.57 mmHg, 95% CI: 5.36–15.78, I2 = 99.2%, P < 0.001) values was observed after resveratrol treatment relative to placebo. The findings of this study indicate that resveratrol supplementation increased some key bone biomarkers, such as ALP and BAP. Further precise clinical trials of the effects of resveratrol supplementation on bone health should be conducted.
Clinical Trial Assessment Principles of National Class III Medical Devices in China
Authors: Min Yue , Gao Jin‐tao , Wu Jing , Zhai Bao , Han Dan , Liu Bin
Published: September 2019

Class III medical devices are defined as those which are implanted inside the human body and applied to maintain normal life and retain original tissue or organic functions. Because these devices are associated with high risk, their effectiveness and safety should be strictly monitored and clinically investigated. The aim of clinical investigation of these medical devices is to ensure the acceptability of their effectiveness and safety levels. On designing the clinical trial, the investigator should determine the indices to assess the effectiveness and safety of medical devices, select reasonable data‐analyzing methods, and pay attention to several other issues. Although some guidelines on specific class III medical devices have illustrated those aspects in detail, there is still no comprehensive report that details all those principles and methodologies. This article aims to summarize the common features among the instruction principles and provide technological support for the clinical study of class III medical devices.
Os Acromiale: Reviews and Current Perspectives
Authors: You Tian , Frostick Simon , Zhang Wen‐tao , Yin Qi
Published: September 2019

Os acromiale is a developmental defect which results from the lack of an osseous union between the ossification centers of the acromion, leading to the fibrocartilaginous tissue connection. The prevalence of os acromiale is 1% to 15%, and is quite common in the African American population. Os acromiale in adults is easily diagnosed by symptoms and X‐ray, particularly on the axillary view; however, the differential diagnosis of adolescents may require MRI or SPECT–CT. Generally, nonoperative therapy for symptomatic os acromiale should be started, including physiotherapy, nonsteroidal anti‐inflammatory drugs, and injections. Surgical treatment is indicated after failed conservative treatment. In symptomatic patients with fixable acromiale, the tension band technique should be used to make the anterior aspect of the acromion elevated from the humerus head. In patients with small fragments which are unsuitable for reattachment, excision might be the best therapeutic option and lead to good outcomes. Whether using internal fixation or resection, the arthroscopic technique results in a better outcome and fewer complications, especially in older patients or athletes with overhead movement, because of the high incidence of shoulder impingement or rotator cuff tears which can be treated concurrently.
DREB/CBF expression in wheat and barley using the stress‐inducible promoters of HD‐Zip I genes: impact on plant development, stress tolerance and yield
Authors: Yang Yunfei , Al‐Baidhani Hadi Hussein Joudah , Harris John , Riboni Matteo , Li Yuan , Mazonka Iryna , Bazanova Natalia , Chirkova Larissa , Sarfraz Hussain Syed , Hrmova Maria , Haefele Stephan , Lopato Sergiy , Kovalchuk Nataliya
Published: September 2019

Networks of transcription factors regulate diverse physiological processes in plants to ensure that plants respond to abiotic stresses rapidly and efficiently. In this study, expression of two DREB/CBF genes, TaDREB3 and TaCBF5L, was modulated in transgenic wheat and barley, by using stress‐responsive promoters HDZI‐3 and HDZI‐4. The promoters were derived from the durum wheat genes encoding the γ‐clade TFs of the HD‐Zip class I subfamily. The activities of tested promoters were induced by drought and cold in leaves of both transgenic species. Differences in sensitivity of promoters to drought strength were dependent on drought tolerance levels of cultivars used for generation of transgenic lines. Expression of the DREB/CBF genes under both promoters improved drought and frost tolerance of transgenic barley, and frost tolerance of transgenic wheat seedlings. Expression levels of the putative TaCBF5L downstream genes in leaves of transgenic wheat seedlings were up‐regulated under severe drought, and up‐ or down‐regulated under frost, compared to those of control seedlings. The application of TaCBF5L driven by the HDZI‐4 promoter led to the significant increase of the grain yield of transgenic wheat, compared to that of the control wild‐type plants, when severe drought was applied during flowering; although no yield improvements were observed when plants grew under well‐watered conditions or moderate drought. Our findings suggest that the studied HDZI promoters combined with the DREB/CBF factors could be used in transgenic cereal plants for improvement of abiotic stress tolerance, and the reduction of negative influence of transgenes on plant development and grain yields.
Laser Lights and Designer Drugs: New Techniques for Descending Levels of Mechanisms “in a Single Bound”?
Authors: Bickle John
Published: September 2019

Optogenetics and DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) are important research tools in recent neurobiology. These tools allow unprecedented control over activity in specifically targeted neurons in behaving animals. Two approaches in philosophy of neuroscience, mechanism and ruthless reductionism, provide explicit accounts of experiments and results using tools like these, but each offers a different picture about how levels of mechanisms relate. I argue here that the ruthless reductionist’s direct mind‐to‐cellular/molecular activities linkages “in a single bound” better fits with both the experimental designs using these tools and some of the scientists’ own judgments about their results than does the mechanist’s “nested hierarchies of mechanisms‐within‐mechanisms.” So at least some important work in current neuroscience appears to be ruthlessly reductive. Mechanism may not correctly characterize all current work in neuroscience, despite its recent popularity.
One week, but not 12 hours, of cast immobilization alters promotor DNA methylation patterns in the nNOS gene in mouse skeletal muscle
Authors: Tomiga Yuki , Ito Ai , Sudo Mizuki , Ando Soichi , Eshima Hiroaki , Sakai Kazuya , Nakashima Shihoko , Uehara Yoshinari , Tanaka Hiroaki , Soejima Hidenobu , Higaki Yasuki
Published: September 2019

Key points

DNA methylation may play an important role in regulating gene expression in skeletal muscle to adapt to physical activity and inactivity.

Neuronal nitric oxide synthase (nNOS) in skeletal muscle is a key regulator of skeletal muscle mass; however, it is unclear whether nNOS expression is regulated by DNA methylation.

We found that 1 week of cast immobilization increased nNOS DNA methylation levels and downregulated nNOS gene expression in atrophic slow‐twitch soleus muscle from the mouse leg. These changes were not detected in non‐atrophic fast‐twitch extensor digitorum longus muscle.

Twelve hours of cast immobilization decreased nNOS gene expression, whereas nNOS DNA methylation levels were unchanged, suggesting that downregulation of nNOS gene expression by short‐term muscle inactivity is independent of the DNA methylation pattern.

These findings contribute to a better understanding of the maintenance of skeletal muscle mass and prevention of muscle atrophy by epigenetic mechanisms via the nNOS/NO pathway.

DNA methylation is a mechanism that controls gene expression in skeletal muscle under various environmental stimuli, such as physical activity and inactivity. Neuronal nitric oxide synthase (nNOS) regulates muscle atrophy in skeletal muscle. However, the mechanisms regulating nNOS expression in atrophic muscle remain unclear. We hypothesized that nNOS expression in atrophic muscle is regulated by DNA methylation of the nNOS promotor in soleus (Sol; slow‐twitch fibre dominant) and extensor digitorum longus (EDL; fast‐twitch fibre dominant) muscles. One week of cast immobilization induced significant muscle atrophy in Sol but not in EDL. We showed that 1 week of cast immobilization increased nNOS DNA methylation levels in Sol, although only a minor change was detected in EDL. Consistent with the increased DNA methylation levels in atrophic Sol, the gene expression levels of total nNOS and nNOSµ (i.e. the major splicing variant of nNOS in skeletal muscle) decreased. The abundance of the nNOS protein and cell membrane (especially type IIa fibre) immunoreactivity also decreased in atrophic Sol. These changes were not observed in EDL after 1 week of cast immobilization. Furthermore, despite the lack of significant atrophy, 12 h of cast immobilization decreased gene expression levels of total nNOS and nNOSµ in Sol. However, no association was detected between nNOS DNA methylation and gene expression. The expression of the nNOSβ gene, another splicing variant of nNOS, in EDL was unchanged by cast immobilization, whereas its expression was not detected in Sol. We concluded that chronic adaptation of nNOS gene expression in cast immobilized muscle may involve nNOS DNA methylation.
A Novel Method of Residual Strain Analysis Via a Non-Bonded Interface Technique in Combination With the Circular Grid Analysis Method
Authors: Gorman Brandon , Farhat Zoheir , Warkentin Andrew
Published: September 2019

A novel non-bonded interface technique (NBIT) is used to analyze internal residual strain by combining a pre-split sample of AISI 4340 steel with the circular grid residual strain analysis technique. NBIT is compared with an implicit non-linear finite element (FE) model using LS-DYNA. A split FE model was compared with a quarter FE model to determine the split interface that causes an average difference of 9.0% on the residual von Mises strain field from a 588.6 N indentation. The homogeneous FE quarter model was then compared with the experimental split model using 588.6, 981.0, and 1471.5 N indentation forces. An average displacement difference of 3.92 µm was found when comparing the experimental split and FE homogeneous samples from a 588.6 N indentation. The internal residual major and minor principal strains from the split experimental sample and homogeneous FE model were compared for each indentation force. The minor principal strain results show the 588.6, 981.0, and 1471.5 N indentation forces resulted in a difference between the experimental split and homogeneous FE model of 28.5%, 34.8%, and 26.0%, respectively. The difference between the comparisons was explained by the inability of the FE model to simulate local non-homogeneous material properties such as grain composition and orientation whereas NBIT does. NBIT can be used for micro- or macro-scale residual strain analysis as the spatial resolution is highly adjustable.
A Review on Wear Between Railway Wheels and Rails Under Environmental Conditions
Authors: Zhu Yi , Wang Wenjian , Lewis Roger , Yan Wenyi , Lewis Stephen R. , Ding Haohao
Published: September 2019

The wheel-rail contact is an open system contact, which is subjected to various environmental conditions, such as temperature, humidity, water, and even leaves. All these environmental factors influence wheel-rail wear. Classical wheel-rail wear has been extensively studied under dry and clean conditions previously. However, with changes in environmental conditions, the wear rate and wear mechanism can change. This paper reviews recent contributions to wheel-rail wear with a special focus on the influence of environmental conditions. The main part includes the basics of wheel-rail wear, experimental methodology, wear and rolling contact fatigue (RCF), and some measures to counter these degradation mechanisms.
Review on the Dynamics of Isothermal Liquid Bridges
Authors: Montanero José M. , Ponce-Torres Alberto
Published: September 2019

In this review, we describe both theoretical and experimental results on the dynamics of liquid bridges under isothermal conditions with fixed triple contact lines. These two major restrictions allow us to focus on a well-defined body of literature, which has not as yet been reviewed in a comprehensive way. Attention is mainly paid to liquid bridges suspended in air, although studies about the liquid–liquid configuration are also taken into account. We travel the path from equilibrium to nonlinear dynamics of both Newtonian liquid bridges and those made of complex fluids. Specifically, we consider equilibrium shapes and their stability, linear dynamics in free and forced oscillations under varied conditions, weakly nonlinear behavior leading to streaming flows, fully nonlinear motion arising during stretching and breakup of liquid bridges, and problems related to rheological effects and the presence of surfactant monolayers. Although attention is mainly paid to fundamental aspects of these problems, some applications derived from the results are also mentioned. In this way, we intend to connect the two approaches to the liquid bridge problem, something that both theoreticians and experimentalists may find interesting.
Design and Testing of a Linear-Driven Electro-Hydrostatic Actuator
Authors: Wang Zimeng , Jiao Zongxia , Li Xinglu
Published: September 2019

This paper presents a novel hydrostatic actuator, which is named as linear-driven electro-hydrostatic actuator (LEHA). In an LEHA, the actuator is driven by a novel collaborative rectification pump (CRP), which incorporates two miniature cylinders and two spool valves. Specifically, the CRP is driven by two linear oscillating motors, which are designed and optimized to generate reciprocating motion at high frequency with adequate stroke. CRP offers a highly novel linear fluid pump with flexibility in bi-directionally driving. In this paper, schematic of LEHA is first presented and its kinematic flow rate equation is derived. Then the design of CRP, linear oscillating motor, as well as the whole LEHA prototype is introduced. Performance of the LEHA is demonstrated through a series of experiments and simulation, and analysis of the results is also included.
Ductile Failure Predictions for the Three-Point Bending Test of a Complex Geometry Made From Aluminum Alloy
Authors: Kubík Petr , Šebek František , Zapletal Josef , Petruška Jindřich , Návrat Tomáš
Published: September 2019

The ductile failure predictions have been an issue in many engineering applications. It begins with a design of machines and tools, continues with an evaluation of manufacturing processes, and last but not least ends with the assessment of various structures. The paper deals with a predictability of used criteria for a random structure of aluminum alloy 2024-T351, which was performed under the conditions of room temperature three-point bending. The bi-failure mode creates a space for the numerical studies of various approaches and gives an insight into the model performance. The plasticity was described by Lode-dependent yield criterion, which was coupled with several pressure and Lode-dependent fracture models to form a continuum damage mechanics approach via the material weakening. It was incorporated through a nonlinear damage accumulation, which was finally implemented using Fortran 77 subroutine into abaqus/explicit. All the models exhibited a good ability of crack onset prediction in terms of the force responses and realistic predictability of the crack propagation. The field of deformations was successfully compared with experimental data obtained by an optical method.
Fatigue Prediction for Molded Wafer-Level Package During Temperature Cycling
Authors: Chuang Wan-Chun , Chen Wei-Long
Published: September 2019

A molded wafer-level package simulation model was successfully developed for calculating solder ball fatigue life during a temperature cycle test (TCT), revealing that the most crucial factor affecting fatigue life, rather than being the maximal stress in solder balls, is the equivalent strain range in solder balls during the creep effect. Accordingly, in a TCT, the fatigue life of the solder balls, which are located from the outer edge to the center, is negatively correlated with the equivalent strain range; the earliest solder balls to rupture are those located at the outer edges, which have the highest equivalent strain range but not the highest stress. Regarding the fatigue life distribution, the simulation results differed from the experiment results by only 6.4%. Additionally, the effects of mold compound protection type and thickness on fatigue life were investigated. When the thickness was changed from 85 to 25 μm, the solder ball fatigue life increased to approximately 1230 cycles, which satisfies the production standard of 500 cycles and is 1.86 times longer than the fatigue life in the existing production line. Reduction in mold compound thickness reduced the amount of material required to 29% of that in the current production line. The model established in this study is expected to be applied in future integrated circuit package design for product reliability.
Model-Based Nonlinear Control of the Dielectric Elastomer Actuator With High Robustness and Precision
Authors: Zhang Mingqi , Cao Xunuo , Chen Xiangping , Zhang Zhen , Chen Zheng , Li Tiefeng
Published: September 2019

Dielectric elastomers (DEs) is one of the promising artificial muscle for soft robots and flexible devices. As one of the key issues for practical applications, the control of DE actuators remains challenging due to the large actuation, electromechanical coupling, and viscoelastic dissipation. Feedforward control and proportional integral derivative (PID) feedback control are recently studied for the control of DE actuators. The control performance is still limited due to the complex dynamic behavior of DE actuators with both nonlinearities and modeling uncertainties. This paper proposes a model-based feedback control for DE actuator, considering nonlinearity of large deformation, electromechanical coupling, and the modeling uncertainties. A nonlinear motion model is proposed and verified by parameter identification experiments. Based on the nonlinear model, we demonstrate a robust control strategy including nonlinear model compensation and robust feedback to decrease the tracking error. The experimental results verify that the control strategy possesses excellent validity to the DE actuator with improved performance compared to the previous strategy of feedforward and PID feedback control. The system design and control strategy of this paper may guide the future design and application of DE actuators, soft robots, and flexible devices.
The Modeling of Redundantly Actuated Mechanical Systems
Authors: Wang Yaojun , Belzile Bruno , Angeles Jorge , Li Qinchuan
Published: September 2019

Dynamics modeling is essential in the design and control of mechanical systems, the focus of the paper being redundantly actuated systems, which bring about special challenges. The authors resort to the natural orthogonal complement (NOC), based on an adaptation of screw theory, to derive the dynamics model. Benefiting from the elimination of the constraint wrenches, the NOC offers a simple, systematic alternative to the modeling of redundantly actuated mechanical systems. The optimum actuator-torque distribution is determined via Euclidean-norm minimization; then, by relying on the QR-decomposition, an efficient and robust method is produced to compute explicitly the right Moore–Penrose generalized inverse of the coefficient matrix. The methodology is illustrated via a case study involving a redundantly actuated parallel-kinematics machine with three degrees of freedom and four actuators.
Rule-Based Alternator Control Using Predicted Velocity for Energy Management Strategy
Authors: Shin Jaewook , Kim Haksu , Baek Seungeon , Sunwoo Myoungho , Han Manbae
Published: September 2019

The market concern of improvement of vehicle safety and its convenience to drive a vehicle has resulted in the growth of the demand for vehicular electronic equipment. This trend requires additional power in the vehicle and thus makes prone to the increase of fuel consumption for vehicles equipped with internal combustion engines. To minimize this fuel consumption, an efficient energy management (EM) strategy for the electrical system of alternator and battery is required. This paper proposes a successful EM strategy based on the rule-based alternator control using predictive information. The proposed strategy reduces fuel consumption by charging batteries using the residual kinetic energy during deceleration. In particular, we predict electrical energy that is recovered by the residual energy using a Markov chain-based velocity prediction algorithm. The accommodation of predicted electrical energy and current vehicle information determines one of the three predefined control modes, such as charge, hold, and discharge, depending on vehicle driving states. This control mode determines the power generation from the alternator and controls the amount of torque to the vehicle electrical system. The proposed strategy is verified through simulation and experiment. The simulation with the new EM strategy is validated as comparing the operation difference with a conventional proportional-integral (PI) control algorithm under the same driver behaviors. Further validation in real vehicle driving experiment shows that fuel consumption was reduced by 2.1% compared to the conventional PI control algorithm.
Low-Dielectric Constant Nanoporous Epoxy for Electronic Packaging
Authors: Jiang Jisu , Keller Landon , Kohl Paul A.
Published: September 2019

Epoxide functionalized poly(propylene carbonate) (ePPC) was included in an epoxy resin formulation and thermally decomposed to create nanoporous epoxy film. The dielectric constant of the porous epoxy was lower than the epoxy formulation control. The introduction of 30% porosity in the epoxy lowered the dielectric constant from 3.78 to 2.76. A postporosity chemical treatment further lowered the dielectric constant. Hexamethyldisilazane (HMDS) was used to terminate the pore walls with the hydrophobic silane layer and reduce both the dielectric constant and tangent loss of the porous epoxy. Two different styrene maleic anhydride crosslinking agents were used in the epoxy formulation, styrene maleic anhydride 2000 (SMA2000) and styrene maleic anhydride 4000 (SMA4000). The effect of the maleic anhydride concentration within SMA on the electrical, mechanical, and thermal properties of porous epoxy film was evaluated. Epoxy films crosslinked with SMA2000 resulted in films with a higher dielectric constant compared to films prepared with SMA4000 due to higher mole fraction of maleic anhydride within SMA2000. However, SMA2000 crosslinked films yielded films with better mechanical and thermal properties. SMA2000 crosslinked films with 30% porosity had a coefficient of thermal expansion (CTE) of 35.2 ppm/K and glass transition temperature of 143 °C.
Longitudinal–Flexural–Torsional Dynamic Behavior of Liquid-Filled Pipelines: An Analytic Solution
Authors: Pavlou Dimitrios G.
Published: September 2019

The 14 partial differential equation system describing the longitudinal–flexural–torsional dynamic behavior of liquid-filled pipelines contains coupled equations due to mutual boundary conditions and Poisson contraction ratio terms. Solutions of the above system are available in the frequency-domain or in the time-domain (method of characteristics (MOC)). In this paper, an analytic solution in the domain of time and space is achieved. Double integral transform, namely, finite sine Fourier transform (FSFT) and Laplace transform, is applied to the derived system of the 14 fourth-order partial differential equations, yielding an algebraic system in terms of the transformed variables. The inversion of the FSFT is an easy task, but the analytic inversion of the Laplace transforms is very challenging. Both integral transform inversions of the 14 transformed variables are successfully performed, and an analytic matrix formula in the domain of time and space along with numerical results is obtained.
On the Hydraulics of Downward Sloping Pipes With Entrapped Air Pockets
Authors: Warda H. A. , Wahba E. M. , Ahmed E. N.
Published: September 2019

In this study, air–water flow in a downward sloping pipe subsequent to the entrapping of an air pocket is investigated both numerically and experimentally. A transient, two-dimensional computational fluid dynamics model is applied to study the different possible flow regimes and their associated phenomena. The numerical model is based on the Reynolds-averaged Navier–Stokes (RANS) equations and the volume of fluid (VOF) method. Both numerical and experimental investigations provide visualization for the hydraulic jump, the blowback regime, and the full gas transport regime. The numerical results predict that the flow structure in the pipe downstream the toe of the hydraulic jump is subdivided into three distinct regions including the jet layer, the shear zone, and the circulation region, which agrees qualitatively with the previous investigations of the hydraulic jump characteristics in open channel flow. Numerical results are in reasonable agreement with the experimental measurements of the circulation length and the hydraulic jump head loss.
A Numerical and Experimental Study on the Fabrication GaN Films by Chemical Vapor Deposition
Authors: Wong Sun , Jaluria Yogesh
Published: September 2019

Computational modeling and simulation are employed to study a rotating susceptor vertical impinging chemical vapor deposition (CVD) reactor to predict GaN film deposition. Many metal-organic chemical vapor deposition reactor manufacturers use prior experience to design and fabricate CVD reactors without a fundamental basis for the process and information on the optimal conditions for the deposition. Through trial and error, they fine tune the gas flow parameters, heater temperatures, chamber pressure, and concentration of species gases for optimal growth. However, expensive raw precursor gas and time are wasted through this method. A computational model is an important step in the CVD reactor design and GaN growth prediction. It can be used to model and optimize the reactor to yield favorable operating conditions. In this paper, a simple geometry consisting of a rotating susceptor and flow guide is considered. The focus is on gallium nitride (GaN) thin films. The study shows how the computational model can benefit reactor design. It also presents comparisons between model prediction results and experimental data from a physical, practical, system. Commercially available software is used, with appropriate modifications, and the results obtained are discussed in detail.
A Simulative and Experimental Approach Toward Eddy Current Nondestructive Evaluation of Manufacturing Flaws and Operational Damage in CFRP Composites
Authors: James Robin , Faisal Haider Mohammad , Giurgiutiu Victor , Lilienthal David
Published: September 2019

The manufacturing process of carbon fiber reinforced polymer (CFRP) composite structures can introduce many characteristic defects and flaws such as fiber misorientation, fiber waviness, and wrinkling. Therefore, it becomes increasingly important to detect the presence of these defects at the earliest stages of development. Eddy current testing (ECT) is a nondestructive inspection (NDI) technique that has been proven quite effective in detection of damage in metallic structures. However, NDI of composite structures has mainly relied on other methods such as ultrasonic testing (UT) and X-ray to name a few and not much on ECT. In this paper, the authors explore the possibility of using ECT in NDI of CFRP composites by conducting simulations and experiments thereafter. This research is based on the fact that the CFRP displays some low-level electrical conductivity due to the inherent conductivity of the carbon fibers. This low-level conductivity may permit eddy current pathways to cause the flow of eddy currents in the CFRP composites that can be exploited for nondestructive damage detection. An invention disclosure describing our high-frequency ECT method has also been processed. First, the multiphysics finite element method (FEM) simulation was used to simulate the detection of various types of manufacturing flaws and operational damage in CFRP composites such as fiber misorientation, waviness, wrinkling, and so on. Thereafter, ECT experiments were conducted on CFRP specimens with various manufacturing flaws using the Eddyfi Reddy eddy current array (ECA) system.
A Two-Dimensional Experimental and Numerical Study of Moonpools With Recess
Authors: Ravinthrakumar Senthuran , Kristiansen Trygve , Ommani Babak
Published: September 2019

Moonpool resonance is investigated in a two-dimensional setting in terms of regular, forced heave motions of a model with moonpool with different rectangular-shaped recess configurations. A recess is a reduced draft zone in the moonpool. Dedicated experiments were carried out. The model consisted of two boxes of 40 cm width each, with a distance of 20 cm between them. Recess configurations varying between 5 cm and 10 cm in length and 5 cm in height were tested. Different drafts were also tested. A large number of forcing periods and five forcing amplitudes were tested. A time-domain boundary element method (BEM) code based on the linear potential flow theory was implemented to investigate the resonance periods, mode shapes, as well as the moonpool response as predicted by the (linear) potential flow theory. Dominant physical effects were discussed, in particular damping due to flow separation from the sharp corners of the moonpool inlet and recess. The effect of the recess on the piston-mode behavior is discussed. The nondimensional moonpool response suggests strong viscous damping at the piston-mode resonance. The viscous BEM (VBEM) simulations demonstrate improvement over inviscid BEM, although further improvement of the method is needed. The VBEM simulations are, in general, in good agreement with the experiments. For the largest recess case, some discrepancies are observed in the amplitude-dependent response amplitude operators (RAOs). The piston-mode shapes are clearly different from the near flat free-surface elevation for a moonpool without recess, consistent with the recently published theory.
Improving the Tribological Properties of Al-7Fe-5Ni Alloys via Friction Stir Processing
Authors: Fekri Soustani M. , Taghiabadi R. , Jafarzadegan M. , Shahriyari F. , Rahmani A.
Published: September 2019

Due to the limited solid-solubility of Fe and Ni in Al, coarse brittle intermetallics rich in Fe and/or Ni are inevitably formed in the as-cast microstructure of Al-Fe-Ni alloys. Upon formation, Fe(Ni)-rich intermetallics significantly deteriorate the properties and restrict the application of alloy in as-cast condition. The purpose of this study was to investigate the effect of friction stir processing (FSP) on microstructure and tribological properties of cast Al-7Fe-5Ni alloy. The dry sliding wear tests were done by using a pin-on-disk type machine under the applied pressures of 1, 2, and 3 MPa, sliding distance of 1000 m, at room temperature. According to the results, FSP (1250 rpm and 8 mm/min) effectively refined the microstructure, especially the coarse primary Al9FeNi intermetallics and eliminated the alloy casting-related defects. FSP also converted the large columnar grains of the cast alloys to the ultrafine equiaxed grains. These microstructural changes enhanced the substrate mechanical properties thereby increased its resistance against sliding-induced plastic flow, leading to the higher tribolayer stability on the surface, and accordingly, higher wear resistance. The results showed that applying 1-pass FSP reduced the wear by 13% and 53% under applied pressures of 1 and 3 MPa, respectively. The friction results also revealed that, compared with the as-cast sample, FSPed samples exhibited lower friction coefficient and friction coefficient fluctuations.
The Benefit of Using Multiple Thin Tanks Versus a Short Big Tank for Thermal Storage in Ceramic-Sphere Packed Bed With Airflow
Authors: Wang Yan , Li Peiwen , Wang Zhifeng , Yang Bei , Yuan Guofeng
Published: September 2019

To make a better thermal storage system that uses air as the heat transfer fluid flowing through a packed-bed of ceramic spheres (Al2O3) as thermal storage materials, the present work studied cases using multiple small-diameter thin tanks to replace a large-diameter big tank while keeping the same total volume and the same air flow rate. Performance analysis of thermal storage has been conducted for comparison and optimization. The long flow passage and faster flow velocity of air in the small-diameter tanks was found to significantly benefit thermal storage performance compared with that of a short big tank. It resulted in a longer duration of discharge of high-temperature airflow, if the same operation time is applied to the two situations. The faster airflow enhances the heat transfer between air and thermal storage material, although it incurs larger pressure loss. Overall, the energy storage efficiency of using several thin tanks can be significantly better than that of using a big short tank if the height-to-diameter ratio in the multiple thin tanks is properly optimized. The optimization methodology and results are of great significance to the development of thermal storage systems that use air as heat transfer fluid and rocks or ceramic spheres as the packed-bed material for thermal storage.
Effects of alternative and natural prey on body size, locomotion and dispersal of Neoseiulus bicaudus (Acari: Phytoseiidae)

Authors: Su Jie , Liu Min , Fu Zhen-Shi , Zhu An-Di , Zhang Jian Ping
Published: September 2019

Prey are very important for the mass rearing of natural enemies and can affect the efficiency and quality of natural enemy products. Locomotion is important in dispersal of predatory mites on plants, and such activity is affected by body size and prey availability. The study evaluates the effects of prey (alternative prey: Tyrophagus putrescentiae Schrank and natural prey: Tetranychus turkestani Ugarov & Nikolskii) on the body size, locomotion and dispersal of the predatory mite Neoseiulus bicaudus Wainstein. When fed the alternative prey, the body size and locomotion of N. bicaudus were significantly lower than when fed the natural prey. However, the dispersal of N. bicaudus fed the two prey types was similar. The results suggest that long-term feeding on alternative prey could decrease the body size and locomotion of N. bicaudus. Nevertheless, the negative effects of alternative prey did not appear to affect the dispersal of N. bicaudus. The likely reason is that the type of prey does not affect the ability of the predatory mite to locate spider mites. In other words, when it fed alternative prey, N. bicaudus could still successfully disperse and locate spider mite-infested plants in the same way as when fed the natural prey.
Bark beetle associated trematurid mites (Acari: Uropodina: Trematuridae) from Asian Russia with description of a new species

Authors: Kontschán Jeno , Szőcs Gábor , Kiss Balázs , Khaustov Alexander A.
Published: September 2019

A new Oodinychus Berlese, 1917 species, O. scolytana sp. nov., was discovered and described from the galleries of bark beetles Polygraphus proximus Blandford from two different parts of Asian Russia. New associations are given for the trematurid mites and bark beetle species. Three bark beetle associated species from the Trichouropoda ovalis-group are moved into the genus Oodinychus as O. hirsuta (Hirschmann, 1972) comb. nov., O. rafalski (Wiśniewski & Hirschmann, 1984) comb. nov. and O. wilkinsoni (Hirschmann &Wiśniewski, 1986) comb. nov. Also, Oodinychus egypticus Abo-Shnaf, El-Bishlawy & Allam, 2018 is transferred to the genus Nenteria Oudemans, 1915.
The Mud Run
Authors: Reese Jason
Published: September 2019

This case study explores the pricing, marketing, and budgeting issues facing a participant obstacle racing event. Students will act as new board members of a junior chamber of commerce, the host organization of a multi-year obstacle racing event. The board is tasked with making decisions about the event related to price setting for entry fees, marketing strategy (including advertising), and budgeting. With the goal of increasing the number of runners, as well as the profit, students will need to use historical data from the event to make informed, data driven decisions. The primary learning objectives include evaluating the various pricing methods available to sports organizations and strategic budget development.
Electrode-free nanopore sensing by DiffusiOptoPhysiology
Authors: Wang Yuqin , Wang Yu , Du Xiaoyu , Yan Shuanghong , Zhang Panke , Chen Hong-Yuan , Huang Shuo
Published: September 2019

Microscopic imaging methods facilitate single-molecule nanopore sensing without the need of electronic connections.
Rock-paper-scissors: Engineered population dynamics increase genetic stability
Authors: Liao Michael J. , Din M. Omar , Tsimring Lev , Hasty Jeff
Published: September 2019

Stabilizing synthetic gene circuits

Making synthetic gene circuits in bacteria is one thing, but making them stable under selective pressure with high mutation rates is another. Liao
et al.
addressed this problem with an ecological strategy in which they created three strains of bacteria, each of which could kill or be killed by one of the other strains (see the Perspective by Johnston and Collins). Once the first strain of bacteria hosting the engineered circuit underwent mutations that decreased function, the system could be “rebooted” by addition of another strain that killed the first but also contained the desired synthetic circuit, allowing its function to proceed unperturbed. This strategy provides a way to control synthetic ecosystems and maintain synthetic gene circuits without using traditional selection to maintain plasmids with antibiotics.

Science
, this issue p.
1045
; see also p.
986
Boltzmann generators: Sampling equilibrium states of many-body systems with deep learning
Authors: Noé Frank , Olsson Simon , Köhler Jonas , Wu Hao
Published: September 2019

Efficient sampling of equilibrium states

Molecular dynamics or Monte Carlo methods can be used to sample equilibrium states, but these methods become computationally expensive for complex systems, where the transition from one equilibrium state to another may only occur through rare events. Noé
et al.
used neural networks and deep learning to generate distributions of independent soft condensed-matter samples at equilibrium (see the Perspective by Tuckerman). Supervised training is used to construct invertible transformations between the coordinates of the complex system of interest and simple Gaussian coordinates of the same dimensionality. Thus, configurations can be sampled in this simpler coordinate system and then transformed back into the complex one using the correct statistical weighting.

Science
, this issue p.
eaaw1147
; see also p.
982
Molecular basis and biological function of variability in spatial genome organization
Authors: Finn Elizabeth H. , Misteli Tom
Published: September 2019

Heterogeneity in genome organization

How the genome is organized in the three-dimensional space of the cell nucleus influences the activity of gene expression. Finn and Misteli review features of genome architecture and cell- and allele-specific variability in spatial genome organization. They also connect stochasticity in gene transcription and variability in genome organization and discuss the functional consequences of genome variability at the cell and population levels in development and disease.

Science
, this issue p.
eaaw9498
Revolutions in agriculture chart a course for targeted breeding of old and new crops
Authors: Eshed Yuval , Lippman Zachary B.
Published: September 2019

Growing more and better food

Increasing human populations demand more productive agriculture, which in turn relies on crop plants adjusted for high-yield systems. Eshed and Lippman review how genetic tuning of the signaling systems that regulate flowering and plant architecture can be applied to crops. Crops that flower sooner might be adaptable to regions with shorter growing seasons, and compact plant shapes might facilitate agricultural management. The universality of these plant hormone systems facilitates application to a range of crops, from the orphan crop teff to the well-known wheat.

Science
, this issue p.
eaax0025
Evolution of a 72-Kilobase Cointegrant, Conjugative Multiresistance Plasmid in Community-Associated Methicillin-Resistant Staphylococcus aureus Isolates from the Early 1990s
Authors: Yui Eto Karina , Firth Neville , Davis Amy M. , Kwong Stephen M. , Krysiak Marcelina , Lee Yung Thin , O’Brien Frances G. , Grubb Warren B. , Coombs Geoffrey W. , Bond Charles S. , Ramsay Joshua P.
Published: September 2019

Horizontal transfer of plasmids encoding antimicrobial resistance and virulence determinants has been instrumental in
Staphylococcus aureus
evolution, including the emergence of community-associated methicillin-resistant
S. aureus
(CA-MRSA). In the early 1990s, the first CA-MRSA strain isolated in Western Australia (WA), WA-5, encoded cadmium, tetracycline, and penicillin resistance genes on plasmid pWBG753 (∼30 kb).
Canopy structure in Late Cretaceous and Paleocene forests as reconstructed from carbon isotope analyses of fossil leaves
Authors: Graham Heather V. , Herrera Fabiany , Jaramillo Carlos , Wing Scott L. , Freeman Katherine H.
Published: September 2019

While modern forests have their origin in the diversification and expansion of angiosperms in the Late Cretaceous and early Cenozoic, it is unclear whether the rise of closed-canopy tropical rainforests preceded or followed the end-Cretaceous extinction. The “canopy effect” is a strong vertical gradient in the carbon isotope (δ13C) composition of leaves in modern closed-canopy forests that could serve as a proxy signature for canopy structure in ancient forests. To test this, we report measurements of the carbon isotope composition of nearly 200 fossil angiosperm leaves from two localities in the Paleocene Cerrejón Formation and one locality in the Maastrichtian Guaduas Formation of Colombia. Leaves from one Cerrejón fossil assemblage deposited in a small fluvial channel exhibited a 6.3‰ range in δ13C, consistent with a closed-canopy forest. Carbon isotope values from lacustrine sediments in the Cerrejón Formation had a range of 3.3‰, consistent with vegetation along a lake edge. An even-narrower range of δ13C values (2.7‰) was observed for a leaf assemblage recovered from the Cretaceous Guaduas Formation, and suggests vegetation with an open canopy structure. Carbon isotope fractionation by Late Cretaceous and early Paleogene leaves was in all cases similar to that by modern relatives, consistent with estimates of low atmospheric CO2 during this time period. This study confirms other lines of evidence suggesting that closed-canopy forests in tropical South America existed by the late Paleocene, and fails to find isotopic evidence for a closed-canopy forest in the Cretaceous.