bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary restriction slightly affects glucose homeostasis and delays plasma cholesterol removal in rabbits with dietary lipid lowering
Authors: Yu Qi , Liu Ruihan , Han Lijuan , Zhang Guangwei , Guan Hua , Pan Qi , Wang Siwang , Liu Enqi
Published: April 2018

Dietary restriction (DR) has been reported to have beneficial effects on atherosclerotic progression as well as lipid and glucose metabolism, but little is known about whether these effects can be enhanced or weakened by dietary lipid lowering. Here, after 12 weeks of high-cholesterol diet feeding, hypercholesterolemic rabbits were fed with either a standard chow diet ad libitum (AL) or a standard chow diet with DR for 16 weeks of dietary lipid lowering. We found that the DR group exhibited a loss of body weight, smaller internal organs, and reduced fat mass, while the AL group accumulated more subcutaneous fat than the baseline group. DR treatment slightly worsened glucose tolerance but enhanced insulin sensitivity, and a slight effect of DR on insulin secretion was also observed. After dietary cholesterol withdrawal, rabbits showed persistent lowering of total cholesterol and triglycerides in plasma. However, the DR group had significantly higher plasma total cholesterol than the AL group at most time points during weeks 7 to 16 of lipid lowering. Although both the AL and DR groups developed more severe atherosclerosis than the baseline group, DR did not improve atherosclerotic progression or the accumulation of macrophages and smooth muscle cells. We conclude that DR affected glucose and lipid metabolism but did not ameliorate atherosclerosis in rabbits when associated with lipid lowering by dietary cholesterol withdrawal.
Use of fiber optic sensing to measure distributed rail strains and determine rail seat forces under a moving train
Authors: Wheeler L.N. , Take W.A. , Hoult N.A. , Le H.
Published: April 2018

Rayleigh backscatter fiber optic sensing permits dynamic strains to be measured along an optical fiber with a gauge spacing and temporal resolution sufficient for rail applications. However, this sensing technology is highly sensitive to vibration. A 7.5 m long section of rail was instrumented with optical fiber and strain measurements were recorded during passage of a freight train slowed to 8–11 km/h. This strategy to minimize rail vibration was successful in permitting distributed dynamic rail strains to be measured under freight car loading. The measured rail strains were used to determine the rail shear forces, which were then used with the static wheel loads to determine the rail seat load for 14 consecutive sleepers as the train passed over the field monitoring site. These data were then combined with measurements of dynamic rail displacement captured using digital image correlation to infer the rail seat load–deflection relationships for individual sleepers. These relationships were observed to provide significantly more detailed information about unsupported voids and the sleeper contact stiffnesses than the traditional consideration of the relationship between applied load and rail deflection and highlights how track behavior at a monitored location can be dependent on the conditions and behavior of neighbouring sleeper.
Three-dimensional stability of compound slope using limit analysis method
Authors: Wang Long , Sun De’an , Li Lin
Published: April 2018

This paper investigates three-dimensional (3D) stability of a compound soil slope with two inclination angles using the limit analysis method. The current limit analysis involves the toe-failure, face-failure, and base-failure mechanisms of the slope, all of which are possible 3D failure mechanisms. By reducing the current compound slope to a simple slope, the validity and efficiency of the present analysis are examined by comparing the current results with published solutions. The 3D stability of a compound soil slope is studied schematically for a wide range of parameters, and the stability charts are presented. The effects of slope shape (i.e., concave and convex shapes) and depth coefficient on the slope stability are investigated graphically. The graphs of critical failure surfaces are also presented to demonstrate the effects of slope shape and depth coefficient on the failure mechanism of a compound soil slope.
Floral trait variation and links to climate in the mixed-mating annual Clarkia pulchella
Authors: Gamble Devin E. , Bontrager Megan , Angert Amy L.
Published: April 2018

The benefits of self-fertilization can vary across environments, leading to selection for different reproductive strategies and influencing the evolution of floral traits. Although stressful conditions have been suggested to favour self-pollination, the role of climate as a driver of mating-system variation is generally not well understood. Here, we investigate the contributions of local climate to intraspecific differences in mating-system traits in Clarkia pulchella Pursh in a common-garden growth chamber experiment. We also tested for plastic responses to soil moisture with watering treatments. Herkogamy (anther–stigma spacing) correlated positively with dichogamy (timing of anther–stigma receptivity) and date of first flower, and northern populations had smaller petals and flowered earlier in response to experimental drought. Watering treatment alone had little effect on traits, and dichogamy unexpectedly decreased with annual precipitation. Populations also differed in phenological response to watering treatment, based on precipitation and winter temperature of their origin, indicating that populations from cool and dry sites have greater plasticity under different levels of moisture stress. While some variation in floral traits is attributable to climate, further investigation into variation in pollinator communities and the indirect effects of climate on mating system can improve our understanding of the evolution of plant mating.
Using hierarchical models to estimate stock-specific and seasonal variation in ocean distribution, survivorship, and aggregate abundance of fall run Chinook salmon
Authors: Shelton Andrew Olaf , Satterthwaite William H. , Ward Eric J. , Feist Blake E. , Burke Brian
Published: April 2018

Ocean fisheries often target and catch aggregations comprising multiple populations or groups of a given species. Chinook salmon (Oncorhynchus tshawytscha) originating from rivers throughout the west coast of North America support mixed-stock ocean fisheries and other ecosystem components, notably as prey for marine mammals. We construct the first coastwide state-space model for fall Chinook salmon tagged fish released from California to British Columbia between 1977 and 1990 to estimate seasonal ocean distribution along the west coast of North America. We incorporate recoveries from multiple ocean fisheries and allow for regional variation in fisheries vulnerability and maturation. We show that Chinook salmon ocean distribution depends strongly on region of origin and varies seasonally, while survival showed regionally varying temporal patterns. Simulations incorporating juvenile production data provide proportional stock composition in different ocean regions and the first coastwide projections of Chinook salmon aggregate abundance. Our model provides an extendable framework that can be applied to understand drivers of Chinook salmon biology (e.g., climate effects on ocean distribution) and management effects (e.g., consequences of juvenile production changes).
Toxoplasma gondii infection induces the formation of host’s nuclear granules containing poly(A)-binding proteins
Authors: Fischer Karlee , Roberts Mikayla , Roscoe Scott , Avci Yasin , Ananvoranich Sirinart
Published: April 2018

To study the mechanism by which human host cells respond to an infection of Toxoplasma gondii, we monitored the level of poly(A)-binding protein (PABP), an indicator of translation. Here, we report an observation of the relocalization of PABPs in human host cells upon T. gondii infection. Notably, the aggregates of PABPs formed upon infection are mainly found in the nucleus, which is a different response from that found after exposure to heat shock. Pyrimethamine treatment of the infected monolayers inhibits the multiplicity of the parasite and reverses the relocalization of PABP aggregates. This active interaction between the infected mammalian host cells and T. gondii appears to be different from that caused by viral infection.
Impact of oblique magnetic viscous dissipative transport on chemically reactive micro-rotations submerged in porous medium
Authors: Mehmood Zaffar , Iqbal Z. , Maraj E.N. , Azhar Ehtsham
Published: April 2018

The present communication aims to investigate the influence of inclined magnetic field and Joule heating phenomenon in the presence of chemical reaction on micro-rotation of particles suspended in a viscoplastic fluid submerged in a porous medium. Casson fluid is considered as a viscoplastic fluid. Governing physical problem modeling and formulation is performed in the Cartesian coordinate system. A system of partial differential equations is reduced to a system of ordinary differential equations by means of suitable transformation. Nonlinear coupled system is solved numerically with the help of a shooting algorithm. Numerical investigation is carried out for strong and weak concentrations at the boundary. Emerging parameters’ effects on fluid micro-rotation velocities and temperature distribution are displayed and analyzed through graphs for strong and weak concentrations. Further, numerical values of skin friction coefficient and Nusselt number are tabulated for pertinent parameters. From the present analysis it is concluded that fluid decelerates with an increase in Casson fluid parameter, medium porosity, magnetic parameter, and inclination angle in both cases of strong concentration as well as weak concentration while it accelerates with the increase in micropolar parameter and Eckert number. Micro-rotation velocity seems to accelerate at the vicinity of stretching surface for β, K, γ, M, and Γ while it decelerates with the increase in Ec. Temperature rises with the increase in Eckert number, Biot number, inclination angle, magnetic parameter, and thermal convection parameter for strong and weak concentration. Skin friction coefficient increases with an increase in micropolar parameter, magnetic parameter, and medium porosity whereas it decreases with an increase in Casson fluid and thermal convection parameters. Nusselt number magnitude rises with an increase in K, Pr, and Bi, while it lessens with an increase in M, Ec, and γ.
Estimating the effect of electron beam interactions with biological tissues
Authors: Yüksel Zeynep , Tufan M. Çağatay
Published: April 2018

The stopping power and range for electrons in matter are the most important parameters in predicting the consequences of the electrons interacting with matter. In this work, we used our previously developed method to calculate these parameters. In our calculation method, the main parameter is the velocity-dependent electronic charge density of the target, which we obtained by using Roothaan–Hartree–Fock (RHF) wave functions. For range calculations, we used the continuous slowdown approach (CSDA), which neglects the energy-loss fluctuations so the incident particle loses its energy in a medium continuously at a rate equal to the total stopping power. The stopping power and CSDA range values have been calculated for electrons incident on brain, breast, and eye tissues. Obtained results have been compared with the available data.
Liver antioxidant and aerobic status improves after metformin and melatonin administration in a rat model of high-fat diet and mammary carcinogenesis
Authors: Kurhaluk Natalia , Bojková Bianka , Winklewski Pawel J.
Published: April 2018

Oxidative stress is involved in the development of various cancers. In the present study, the effect of long-term administration of peroral antidiabetic metformin and pineal hormone melatonin on liver antioxidant and aerobic status in female Sprague-Dawley rats carrying mammary tumors induced by N-methyl-N-nitrosourea was evaluated. Both substances were administered in a preventive and curative manner (12 days before and 16 weeks after the carcinogen application). Carcinogen administration induced oxidative stress: the level of thiobarbituric acid reactive substances (TBARS) considered as a marker of reactive oxygen species (ROS) generation in liver increased as well as the level of oxidatively modified protein content (OMP; aldehyde and ketone derivates). Metformin administration restored succinate dehydrogenase and lactate dehydrogenase activity and associated ROS production and OMP content to the level of intact rats, with predominant activation of superoxide dismutase (SOD) and glutathione reductase (GR). Melatonin alone and in combination with metformin also decreased TBARS content. OMP content decreased in all groups receiving chemoprevention. The rise in total antioxidant capacity after melatonin and particularly metformin and melatonin combination might result from the initiation of anaerobic metabolism and increasing SOD, GR, and glutathione peroxidase activity. Long-term administration of metformin and melatonin exerts antioxidant properties in liver, especially in combination.
Responses of spring-seeded cover crop roots by herbicide residues and short-term influence in soil aggregate stability and N cycling
Authors: Rojas María A. , Van Eerd Laura L. , O’Halloran Ivan P. , Sikkema Peter H. , Robinson Darren E.
Published: April 2018

Cover crop (CC) prevalence between cash crop systems is contributing to long-term sustainable crop production systems. However, herbicide residue impact on CC root growth and its subsequent effect on soil aggregation and fertility are unknown. An untreated control plus preemergence (PRE) application of saflufenacil (at 67 and 134 g a.i. ha−1)/dimethenamid-P (at 668 and 1336 g a.i. ha−1) as well as S-metolachlor (at 1600 and 3200 g a.i. ha−1)/atrazine (at 1280 and 2560 g a.i. ha−1) + mesotrione at 140 and 280 g a.i. ha−1to sweet corn (Zea mays L. var. rugosa Bonaf.) and imazethapyr (100 and 200 g a.i. ha−1) to pea (Pisum sativum L.) were made in spring 2011 and spring 2012. One year later, ryegrass (Lolium multiflorum Lam.), buckwheat (Fagopyrum esculentum Moench), sorghum–sudangrass [Sorghum bicolor (L.) Moench × S. bicolor var. sudanese (L.)], and spring wheat (Triticum aestivum L.) were seeded. Root biomass and N content, wet aggregate stability (WAS), and aggregate size plus soil mineral N (SMN) were determined. Buckwheat root biomass declined in all herbicide treatments but root N declined in imazethapyr and S-metolachlor/atrazine + mesotrione at the 2× and 1× rates, respectively. Ryegrass root biomass decreased in S-metolachlor/atrazine + mesotrione but root N content declined only at the 2× rate. Sorghum–sudangrass and spring wheat roots decreased in imazethapyr and S-metolachlor/atrazine + mesotrione at the 2× rate, respectively. Despite the impact of herbicide residues on roots, differences in aggregate size, WAS, and SMN were not detected. Findings from this study add knowledge on herbicide residue effect on CC root growth and provide useful CC seeding guidelines for growers.
Transcriptome-based identification of genes related to resistance against Botrytis elliptica in Lilium regale
Authors: Cui Qi , Liu Qiang , Gao Xue , Yan Xiao , Jia Gui-Xia
Published: April 2018

A major production constraint of lilies is gray mold caused by the necrotrophic fungus Botrytis elliptica. The molecular basis of lily plant resistance to B. elliptica remains largely unexplored. To systematically dissect transcriptomic responses, we constructed four RNA-seq libraries from the leaves of Lilium regale, a promising Chinese wild Lilium species, after B. elliptica infection for 0, 4, 12, or 24 h. The sequence reads were assembled into 96 416 unigenes, of which 7697 were differentially expressed. Profiling analysis revealed changes in gene expression, including 2261 downregulated genes and 3599 upregulated genes. Quantitative real-time polymerase chain reaction analysis of 39 defense-related unigenes confirmed that the transcriptional changes of these genes presented in the RNA-seq data were predominately affected by B. elliptica infection. Key B. elliptica modulated genes played roles in defense responses mediated by phytohormones involved in jasmonate signaling, whereas salicylic acid and ethylene were not involved. Among transcription factors, some WRKYs, MYB, and ethylene responsive factor were clearly upregulated. Additionally, a group of genes encoding known important defense-related proteins, such as receptor-like kinases, antioxidant enzymes, polyphenol oxidase, pathogenesis-related proteins, and proteins associated with phenylpropanoid metabolism, exhibited high transcript abundances. Furthermore, the expressions of selected candidate genes were induced more rapidly and strongly in the resistant genotype than in the susceptible genotype. Taken together, the results provide a better understanding of the defense responses involved in the crosstalk between the lily and B. elliptica and a valuable set of sequence data for gray mold resistant candidate gene discovery.
Potential SNPs related to microspore culture inRaphanus sativusbased on a single-marker analysis
Authors: Chung Yong Suk , Lee Yun Gyeong , Silva Renato Rodrigues , Park Suhyoung , Park Min Young , Lim Yong Pyo , Choi Sang Chul , Kim Changsoo
Published: April 2018

Radish (Raphanus sativus) is an economically important crop grown for its edible roots and leaves. It is a self-incompatible, outcrossing species, making the production of homozygous lines and the development of breeding populations difficult. However, this can be overcome with haploids production techniques using isolated microspores, providing the rapid production of homozygous lines for breeding. Thus, it would be useful to identify radishes with a high regeneration rate from microspore culture. In the current study, 96 radish cultivars or germplasms were evaluated for high regeneration rates. Also, a single-marker analysis (SMA) was applied to detect single nucleotide polymorphisms (SNPs) potentially associated with this trait using genotype-by-sequencing (GBS) technology. The regeneration rate from microspore culture of 96 lines showed a wide range, from 0% to 269.5%. From the SMA, 52 markers were detected at a p value of 0.001 and a total of 11 physically nearby genes with high levels of similarity in various species were identified as candidates for high regeneration rates. This result could be used for clarifying the genetic basis underlying these traits and developing molecular markers associated with regeneration rates and would be beneficial for generating homozygous inbred lines.
Exploring agronomic strategies to improve oat productivity and control weeds: leaf type, row spacing, and planting density
Authors: Li Pufang , Mo Fei , Li Defeng , Ma Bao-Luo , Yan Weikai , Xiong Youcai
Published: April 2018

The trade-off between crop production and weed control is a fundamental scientific issue, as it is frequently influenced by individual crop competitive ability, population density, and planting pattern. A 2 yr field study was conducted to examine the relationship between planting density and row spacing, using two contrasting oat varieties. On average, high planting density (480 plants m−2) reduced weed biomass at oat maturity by 59% in 2012 and by 56% in 2013, when compared with a low density (120 plants m−2). The droopy-leaf variety suppressed weed biomass by up to 69% and weed density up to 72%, compared with the erect-leaf variety. In a drier year, the greatest grain yield was achieved with the droopy-leaf variety under the intermediate density, while in 2013, the erect-leaf variety under the high density had similar yield to the droopy-leaf variety at the intermediate density. A general trend was that increasing plant density suppressed weed infestation, and promoted crop biomass and yield. The droopy-leaf variety exhibited a strong competitive ability under the intermediate planting density, while the erect-leaf variety had a strong competitive ability under the high density. Taken together, there was a complex variety-by-environment interaction to achieve the balance between crop production and weed suppression, which was mediated by growing-season conditions.
Rudiment resorption as a response to starvation during larval development in the sea urchin Strongylocentrotus droebachiensis
Authors: Singh A. , Pinto L. , Martin C. , Rutherford N. , Ragunathan A. , Upadhyay U. , Kapoor P. , McRae M. , Siddiqui A. , Cantelmi D. , Heyland A. , Wray G. , Stone J.R.
Published: April 2018

Phenotypic flexibility (reversible phenotypic change) enables organisms to couple internal, ontogenetic responses with external, environmental cues. Phenotypic flexibility also provides organisms with the capacity to buffer stereotypical internal, developmental processes from unpredictable external, ecological events. Echinoids exhibit dramatic phenotypic flexibility in response to variation in exogenous nutrient supplies. The extent to which echinoids display this flexibility has been explored incompletely and research hitherto has been conducted predominantly on larval structures and morphologies. We investigated experimentally the extent to which the primordial juvenile, the developing rudiment, can exhibit the first phase in phenotypic flexibility among individuals. We report for the first time on rudiment regression and complete resorption as a response to starvation during larval development in the sea urchin Strongylocentrotus droebachiensis (O.F. Müller, 1776) and identify a developmental “window of opportunity” within which this can occur. Based on our observations and previous suggestions, we speculate that sea urchin rudiments might provide means of buffering development during unfavorable conditions.
Draft Reduction by Vibratory Soil Cutting
Authors: Sulatisky M.T. , Ukrainetz P.R.
Published: April 2018

With the increasing size of cultivating and excavating equipment, engineers have been faced with the problem of transmitting large drawbar forces, yet keeping the weight of tractors or machines to a minimum. This paper shows how draft forces can be reduced significantly by vibrating the soil-cutting blade.

A fully instrumented laboratory testing facility was designed and constructed to test various types of vibrating blades. A carriage, which was pulled the length of the test bed along two parallel shafts by a hydraulic motor, supported a hydraulic servo-valve, actuator, and linkage which vibrated the blade. It was possible to conduct tests in three modes of vibration; horizontal, vertical, and at 45 degrees. Draft was recorded by a strain gauge force transducer attached to the carriage.

Preliminary testing of a knife-edged, vertical blade for laying underground cable was undertaken. The blade, which was pulled at a depth of 9 in., was vibrated at frequencies up to 30 Hz and amplitudes (zero to peak) up to 1.0 in. It was found, for example, that a frequency and amplitude of 10 Hz and 0.5 in., respectively, yielded draft force reductions as high as 80%.
Instability in Boundary-Layer Free Convection along an inclined Plate
Authors: Lee J.B. , Lock G.S.H.
Published: April 2018

This paper gives theoretical consideration to the problem of the stability of laminar, boundary-layer, free-convection flow of air along a long, inclined plane surface heated isothermally. The analysis considers two forms of small disturbance: a two-dimensional wave disturbance, and a set of longitudinal roll vortices. Development of the appropriate disturbance equations is followed by their numerical solution. The effect of inclination on the neutral stability curves for both disturbance forms is presented graphically along with a comparison of the critical Rayleigh numbers obtained from both disturbance forms.
On Buckling Paradox
Authors: Dubey R.N.
Published: April 2018

A reinterpretation of Shanley’s model of plastic loading is introduced. The new model is used to calculate buckling stress in an elastic-plastic rectangular plate under uniaxial compression. The result is a significant reduction in the buckling stress.
Optimal Design of Laminated Composite Plates Under Axial Compression
Authors: Joshi S.P. , Iyengar N.G.R.
Published: April 2018

The study is carried out for the optimum design of laminated fiber reinforced composite plates, subjected to multiple in-plane loadings. Angle-ply laminates with orthotropic laminae are considered. Thickness of plies and corresponding fiber orientations are incorporated as design variables. The constrained optimization problem is transformed into a series of unconstrained optimization problems, using an interior penalty function approach. The results have been obtained for different aspect ratios and uniform biaxial in-plane loading ratios. This study shows that the fiber orientations of the plies near mid-plane have little effect on the optimum design. There exists a particular fiber orientation angle for the over all thickness of laminate, which results in the optimum design for a plate of a given aspect ratio under a given set of loadings.
Vorticity and Vortex Dynamics in Complex Turbulent Flows
Authors: Hunt J.C.R.
Published: April 2018

Some of the basic principles of vortex dynamics arc reviewed in this paper and applied to calculating and understanding various kinds of turbulent flows. After setting out the basic equations and boundary conditions, the different principles are illustrated for special eases where different simplifications are justified. The displacement of two-dimensional vorticity is applied to two-dimensional shear flows over slender shapes (such as humps or hills on surfaces where the ‘triple-deck’ method is explained in terms of vorticity). The general changes of vorticity and velocity are related to the movement of fluid-line elements. A new geometrical proof for the changes in velocity is given. These concepts are applied to distorted turbulent flows (isotropic and anisotropic) and shear flows. Recent results on the forces on and motions of finite fluid volumes in rotational, non-uniform flows are reviewed and it is shown that the inertial or added mass effects are generally of greater importance than the distortion of the vorticity field. This gives some new insight into Prandtl’s mixing length theory. A simple class of interaction between vortices is reviewed to illustrate how the interactions differ depending on the relative strengths of the vortices. Finally, some new ideas are reviewed on vorticity shed from surfaces and how this interacts with vorticity advected onto a body from upstream.
Effects of Mechanical and Thermal Relaxations on the Stresses in a Heated Viscoelastic Continuum with a Cylindrical Hole
Authors: Misra J.C. , Kar S.B. , Samanta S.C.
Published: April 2018

The paper deals with a problem of stress analysis in a heated viscoelastic medium containing a cylindrical hole. The medium is taken to be viscoelastic in shear but elastic in bulk deformation; the linear standard model is used to characterize the viscoelastic behaviour of the material. The analysis is carried out for two different sets of conditions for the bounding surface. The applicability of the analysis put forward in the paper has been illustrated through an attempt to compute the desired expressions by using suitable numerical techniques. The computed results are found to be in good agreement with those of related previous studies.
EQUATIONS OF MOTION OF COMPLEX MULTIBODY SYSTEMS USING KINEMATICAL DIFFERENTIALS
Authors: HILLER M. , KECSKEMETHY A.
Published: April 2018

In complex multibody systems the motion of the bodies may depend on only a few degrees of freedom. For these systems, the equations of motion of minimal order, although more difficult to obtain, give a very efficient formulation. The present paper describes an approach for the automatic generation of these equations, which avoids the use of LAGRANGE-multipliers. By a particular concept, designated “kinematical differentials”, the problem of determining the partial derivatives required to state the equations of motion is reduced to a simple re-evaluation of the kinematics. These cover the solution of the global position, velocity and acceleration problems, i.e. the motion of all bodies is determined for given generalized (independent) coordinates. For their formulation and solution, the multibody system is mapped to a network of nonlinear transformation elements which are connected by linear equations. Each transformation element, designated “kinematical transformer”, corresponds to an independent multibody loop. This mapping of the constraint equations makes it possible to find closed-form solutions to the kinematics for a wide variety of technical applications, and (via kinematical differentials) leads also to an efficient formulation of the dynamics. The equations are derived for holonomic, scleronomic systems, but can also be extended to general nonholonomic systems.
BENDING ANALYSIS OF ORTHOTROPIC CONICAL SHELLS
Authors: Tong Liyong , Tabarrok B. , Wang Tsun Kuei
Published: April 2018

Using Donnell type shell theory a simple and exact procedure is presented for bending analysis of orthotropic conical shells under various loads. The solution is in the form of a power series in terms of a particularly convenient coordinate system, and its convergence radius is obtained.
EVALUATION OF MACHINED SURFACE TEXTURE USING A VISION SENSOR
Authors: Kurada S. , Bradley C.
Published: April 2018

A non-contact measurement technique was developed for the in-cycle assessment of ground surface texture. The system utilises off-the-self vision components to capture the pattern of scattered light from the surface, which is illuminated by a white light source at a shallow grazing angle. Three parameters, related to the surface texture, were derived from the pattern and correlation curves were established by plotting the three textural parameters against the corresponding average surface roughness Ra obtained from a stylus profilometer. A set of test samples, ground to a pre-determined roughness, were used to estimate the efficacy of the measurement technique. The proposed technique is fast and reliable means of extracting textural information from ground surfaces and, furthermore, it can be easily adapted to use in a production environment.
A NUMERICAL METHOD FOR THE KINEMATIC ANALYSIS OF SPATIAL MECHANISMS USING POINT COORDINATES
Authors: Attia H.A.
Published: April 2018

A numerical method for the kinematic analysis of spatial mechanisms with lower pairs is presented. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the kinematic joints. The formulation in terms of this system of coordinates is simple and it involves elementary mathematics. The method suggests a new approach for choosing and classifying the different points and links in the mechanisms. Two examples are used to demonstrate the simplicity and efficiency of the proposed method.
CALIBRATION OF THE 3-PRS PARALLEL MANIPULATOR USING A MOTION CAPTURE SYSTEM
Authors: van Driel C.G. , Carretero Juan A.
Published: April 2018

In this paper, a kinematic calibration method for the 3-PRS parallel manipulator using a motion capture system is presented. Although parallel mechanisms present numerous advantages over their serial counterparts, an accurate kinematic model must be developed to facilitate their operation. Kinematic calibration is used to accurately determine the kinematic parameters of the kinematic model to improve the overall accuracy of the mechanism. The kinematic calibration of the 3-PRS parallel manipulator will be examined by identification of the manipulator's kinematic parameters, an introduction to the motion capture system used, and the presentation of die calibration method itself. For preliminary testing purposes, a virtual model of the manipulator has been generated in CAD to validate the calibration method. The calibration method initially determines the joint locations and orientations, from which the remaining kinematic parameters can be resolved. Preliminary testing using the virtual model indicates the method is valid and can accurately determine the modelled parameters. Once the physical manipulator is operational, alterations the calibration method will be required to account for manufacturing and assembly tolerances/errors, joint offsets and noise during the static captures.
THE LAGRANGIAN DERIVATION OF KANE’S EQUATIONS
Authors: Parsa Kourosh
Published: April 2018

The Lagrangian approach to the development of dynamics equations for a multi-body system, constrained or otherwise, requires solving the forward kinematics of the system at velocity level in order to derive the kinetic energy of the system. The kinetic-energy expression should then be differentiated multiple times to derive the equations of motion of the system. Among these differentiations, the partial derivative of kinetic energy with respect to the system generalized coordinates is specially cumbersome. In this paper, we will derive this partial derivative using a novel kinematic relation for the partial derivative of angular velocity with respect to the system generalized coordinates. It will be shown that, as a result of the use of this relation, the equations of motion of the system are directly derived in the form of Kane’s equations.
ARE PARALLEL ROBOTS MORE ACCURATE THAN SERIAL ROBOTS?
Authors: Briot Sébastien , Bonev Ilian A.
Published: April 2018

It is widely claimed that parallel robots are intrinsically more accurate than serial robots because their errors are averaged instead of added cumulatively, an assertion which has not been properly addressed in the literature. This paper addresses this void by comparing the kinematic accuracy of two pairs of serial-parallel 2-DOF planar robots. Only input errors are considered and all robots are optimized for accuracy, the only constraint being that they cover a given desired workspace. The results of this comparison seem to confirm that parallel robots are less sensitive to input errors than serial robots. However, this comparison is too limited to draw any general conclusions. Besides, it is virtually impossible to make a meaningful comparison between other pairs of serial and parallel robot. Therefore, there is no simple answer to this question of superiority.
TOWARD THE DESIGN AND SIMULATION OF A NEW GENERATION OF RECONFIGURABLE SPACE MANIPULATORS USING TELESCOPING PASSIVE JOINTS
Authors: Hebert P. , Tatossian C. , Caims M. , Aghili F. , Parsa K. , Morozov A.
Published: April 2018

This work presents the analysis, simulation, design, and assembly of a three-degree-of-freedom reconfigurable robotic arm. Unlike conventional reconfigurable robots, the final design illustrated in this paper does not achieve re-configurability through modular joints; instead, it is equipped with passive telescopic joints. These passive joints allow the robotic arm to change its Denavit-Hartenberg parameters via an innovative braking system. The robotic arm itself presents many advantages; not only is it versatile to perform various tasks, but it can be packed into a small volume, as usually required for launch in space applications.
USING DOUBLE ENVELOPE METHOD ON A PLANETARY GEAR MECHANISM WITH DOUBLE CIRCULAR-ARC TOOTH
Authors: Tsai Chun-Fang , Liang Tsang-Lang , Yang Shyue-Cheng
Published: April 2018

A geometric model and mathematical model of planetary gear mechanism with double circular-arc teeth is determined using the imaginary rack cutters and double envelope concept. The mathematical model of a ring gear with double circular-arc teeth in a second envelope has been developed. In this paper, the conditions of the gear meshing and contact load of the gears are simulated by assembly errors. The goal of the stress analysis is to determine the contact stress on the planet gear and ring gear, and planet gear and sun gear. Given the assembly errors of the planetary gear mechanism including center distance error and mis-aligmment error, the maximum von-Mises stress in the planetary gear mechanism with double circular-arc teeth is analyzed using visualNastran desktop package. It is found that the center distance error is more critical to mis-alignment error.
GREENING THE UK BUILDING STOCK: Historic Trends and Low Carbon Futures 1970-2050
Authors: Brown A I , Hammond G P , Jones C I , Rogers F J
Published: April 2018

Historic trends and future projections of energy use and carbon dioxide emissions associated with the United Kingdom building stock are analysed for the period 1970-2050. Energy use in housing is found to rise at a slightly slower rate than the increase in household numbers, which totalled some 25.5 million in 2000. It appears feasible to reduce carbon dioxide (CO2) emissions in the UK domestic building stock by more than 65% by 2050. But this would require a significant take-up of energy saving measures and the adoption of various low or zero carbon (LZC) energy technologies. Non-domestic buildings consisted of some 1.98 million premises in 2000. Anticipated changes in the UK Building Regulations will lead to reductions in energy use and carbon emissions of up to 17% and 12% respectively for 2010 standard buildings. Improvements in the non-domestic building stock and industrial processing could lead to a reduction of nearly 59% in CO2 emissions, via the adoption of LZC energy technologies. Thus, the potential for ‘greening' the UK building stock – making it environmentally benign - is large, but the measures needed to achieve this would present a significant challenge to the UK government, domestic householders, and industry in the broadest sense.
PIECE-WISE CAUSAL INVERSION BY OUTPUT REDEFINITION FOR A FLEXIBLE LINK MANIPULATOR
Authors: Vakil M. , Fotouhi R. , Nikiforuk P. N.
Published: April 2018

A new causal dynamic end-effector inversion method for a single flexible link manipulator is introduced. Contrary to the available non-causal inversion technique, this method does not lead to pre-actuation and works even in the presence of the purely imaginary zeros for the transfer function. Based on this approach, the desired end-effector trajectory is divided into a finite number of segments. In each segment, the desired trajectory is redefined so that a bounded continuous torque through causal dynamic inversion is obtained. The redefinition of the desired trajectory at each segment employs summation of stable exponential functions. This leads to a family of answers for the redefined trajectory, which is an advantage for control engineers. The results of the simulation and experimental studies show the feasibility and effectiveness of this new technique.
OPTIMIZATION OF THE C3MR CYCLE WITH GENETIC ALGORITHM
Authors: Taleshbahrami Hamidreza , Saffari Hamid
Published: April 2018

The aim of this paper is thermodynamic simulation and optimization of the C3MR system with Genetic Algorithm. For this purpose, in the first step, the Peng Robinson equation of state is simulated with a code in MATLAB and then used for simulating thermodynamic properties of natural gas and refrigerants that are used in the cycle. Following that the cycle is thermodynamically simulated and composite curves for subcooling and liquefaction heat exchangers are plotted. If composite curves in heat exchangers approach, the total power will decrease. Then, the total power used by the compressors is calculated. In the next step, the thermodynamic modeling is linked with Genetic Algorithm and the total power consumed by compressors is defined as objective function. The best value resulted from optimization has 23% lower power than the base design. In addition, heat exchange curves closed together.
SIMULATION OF A ROTATING DEVICE THAT REDUCES THE AERODYNAMIC DRAG OF AN AUTOMOBILE
Authors: Gagnon Louis , Richard Marc J. , Lévesque Benoît
Published: April 2018

A two-dimensional Computational Fluid Dynamics (CFD) analysis of the Ahmed body is performed using the k-omega-SST turbulence model implemented in the OpenFOAM (OF) software. The analysis is then modified to include a rotating paddle wheel which captures energy from the swirl that forms behind the vehicle. The rotating wheel is implemented using a General Grid Interface (GGI) in the mesh. Flow energy is captured by the wheel and the power generated by the wheel reaches 16.1 W at optimal conditions. Overall drag reductions of up to 7.6% are also found as side-effects of the rotating paddle wheel. Computations are run in parallel on a dual core computer. A mesh of 30,000 cells is used. Y+ values on the walls of the vehicle range from 60 to 500. Tests are run at both fixed and variable paddle wheel angular velocities.
NUMERICAL STUDY OF A HOT-AIR-BASED AIRCRAFT WING ANTI-ICING SYSTEM USING THE BOX-BEHNKEN DoE APPROACH
Authors: Hannat Ridha , Morency François , Decoster Louis
Published: April 2018

This article proposes the use of the Box-Behnken design of experiment (DoE) methodology to study an aircraft anti-icing system. The anti-icing system consisted of a piccolo tube with round apertures for producing air jets inside a wing. Mass flow, jet to wall distance, and jet impact angle were varied, starting from an initial design, in order to maximize heat transfer effectiveness. A conjugate heat transfer procedure from commercial CFD software was used to solve for cold air external flow, compressible internal flow, and thermal conduction in the airfoil skin. The DoE methodology was validated using a single impinging jet. A quadratic model of the heat transfer effectiveness of the anti-icing system was then built using the methodology and the maximal value was sought.
STRUCTURAL SYNTHESIS OF ANCIENT CHINESE ORIGINAL CROSSBOW
Authors: Hsiao Kuo-Hung
Published: April 2018

The original crossbow was one of the most important weapons in ancient China. Since crossbows have diversified types and were widely used in ancient China after the Spring and Autumn Period (770-476 BC), the original crossbow should have many designs in different eras and regions. The aim of this work is to synthesize mechanism structures of the original crossbow. Based on the analyses of crossbows, the structural characteristics and design constraints of this device are concluded. Then, according to the concepts of generalization and specialization subject to the concluded design constraints, twelve feasible structures of mechanism that meet the technological standards of the subject’s time period are reconstructed.
APPLICATION OF HOMOGENOUS TRANSFORMATION MATRIX TO THE MODELING OF A BALL-END CUTTER
Authors: Hsieh Jung-Fa
Published: April 2018

This paper presents a comprehensive and straightforward method for the mathematical modeling of a generic ball-end cutter. In the proposed approach, a mathematical model of the rake surface is developed based on a normal helix cutting edge geometric model. A mathematical model of the flank surface is then derived based on the assumption of a constant clearance angle. The proposed model is applicable to a wide range of ball-end cutters. As a result, it provides an ideal basis for the generation of the NC equations required to machine ball-end cutters on a 6-axis CNC grinding machine.
THREE-PHASE-LAG HEAT CONDUCTION IN A FUNCTIONALLY GRADED HOLLOW CYLINDER
Authors: Akbarzadeh Abdolhamid , Fu Jiawei , Chen Zengtao
Published: April 2018

Heat conduction in a functionally graded, infinitely-long hollow cylinder is studied based on the three-phase-lag model. Material properties except the phase-lags vary according to a power-law within the cylinder. The phase-lag heat conduction equation is written in a form in which various models of heat conduction theories can be generated. The governing differential equations in the Laplace domain are solved exactly and a numerical Laplace inversion technique is employed for restoring results in the time domain. The effects of different heat conduction theories, phase-lags, geometries, and non-homogeneity indices are studied on the spatial distribution and time-history of temperature.
EMBODIMENT DESIGN OF NOVEL 5-SPEED REAR DRIVE HUBS FOR BICYCLES
Authors: Wu Yi-Chang , Wu Tze-Cheng
Published: April 2018

This paper presents embodiment design of 5-speed rear drive hubs for bicycles. A 7-link, 2-degrees of freedom (DOF) compound planetary gear train as the main body of a rear drive hub is introduced. The relationship between the number of coaxial links of a planetary gear train and the number of gear stages that a drive hub can provide with is discussed. By means of kinematic analysis, four speed ratios of the planetary gear train are derived, which represents four forward gears of the rear drive hub. By adding a direct-drive gear, five forward gears can be provided and two feasible clutching sequence tables are synthesized. Manual translational-type gear-shifting mechanisms are further designed to incorporate with the planetary gear train for appropriately controlling the gear stage. The power-flow path at each gear stage is checked to verify the feasibility of the proposed design. Finally, two novel 5-speed bicycle rear drive hubs are presented.
THE SYNTHESIS OF THE PLANAR LINKAGES WITH SYMMETRICAL CONFIGURATIONS
Authors: Chu Chia-Chun , Lu Deng-Maw
Published: April 2018

The mechanisms that employ symmetrical configurations can be found in the steering mechanisms, double open refrigerator, roof boxes, and double open windows, among others. They are useful for some special applications with kinematic symmetry. There have been studies about the linkage synthesis, especially in the research of planar closed chains, from as early as 1960s. However, no study has focused on the symmetry of planar linkages. Thus, the purpose of this paper is to present a methodology to synthesize the configurations of planar linkages. The systematic methodology can be divided into structure synthesis, configuration synthesis and results produced from three major processes. Finally, four suitable results of up to six-bar linkages can be obtained, for example. The four results include one four-bar linkage and three six-bar linkages.
On the association schemes with the thin radical series
Authors: Bagherian Javad
Published: April 2018

In this paper, we first show that the wedge product of a thin association scheme and a schurian association scheme is schurian. Then as an application of this result, we investigate the schurity problem for the association schemes having the thin radical series. We show that these association schemes are schurian under some conditions on the successive quotients of their thin radical series.