WorldWideScience

Sample records for stabilizing effects mse

  1. Design parameters and methodology for mechanically stabilized earth (MSE) walls.

    Science.gov (United States)

    2014-10-01

    Since its appearance in 1970s, mechanically stabilized earth (MSE) walls have become a majority among all types of retaining walls due to their economics and satisfactory performance. The Texas Department of Transportation (TxDOT) has primarily adopt...

  2. Interaction between drilled shaft and mechanically stabilized earth (MSE) wall : project summary.

    Science.gov (United States)

    2015-08-31

    Drilled shafts are being constructed within the reinforced zone of mechanically stabilized earth (MSE) walls (Figure 1). The drilled shafts may be subjected to horizontal loads and push against the front of the wall. Distress of MSE wall panels has b...

  3. Development of LRFD resistance factors for mechanically stabilized earth (MSE) walls : [technical summary].

    Science.gov (United States)

    2013-12-01

    Bridge approach embankments and many other : transportation-related applications make use of : reinforced earth retaining structures. Mechanically : Stabilized Earth (MSE) walls are designed under : the Load and Resistance Factor Design (LRFD) : meth...

  4. 0-6716 : design parameters and methodology for mechanically stabilized earth (MSE) walls.

    Science.gov (United States)

    2013-08-01

    Since their appearance in the 1970s, mechanically : stabilized earth (MSE) walls have become a majority : among all types of retaining walls due to their economics : and satisfactory performance. The Texas Department of : Transportation (TxDOT) has p...

  5. Evaluation of geofabric in undercut on MSE wall stability : executive summary report.

    Science.gov (United States)

    2011-05-01

    Compaction of granular base materials at sites with fine grained native soils often causes unwanted material loss due to penetration. In 2007, ODOT began placing geofabrics in the undercut of MSE walls at the soil/ granular material interface to faci...

  6. What side effects are problematic for patients prescribed antipsychotic medication? The Maudsley Side Effects (MSE) measure for antipsychotic medication.

    Science.gov (United States)

    Wykes, T; Evans, J; Paton, C; Barnes, T R E; Taylor, D; Bentall, R; Dalton, B; Ruffell, T; Rose, D; Vitoratou, S

    2017-10-01

    Capturing service users' perspectives can highlight additional and different concerns to those of clinicians, but there are no up to date, self-report psychometrically sound measures of side effects of antipsychotic medications. Aim To develop a psychometrically sound measure to identify antipsychotic side effects important to service users, the Maudsley Side Effects (MSE) measure. An initial item bank was subjected to a Delphi exercise (n = 9) with psychiatrists and pharmacists, followed by service user focus groups and expert panels (n = 15) to determine item relevance and language. Feasibility and comprehensive psychometric properties were established in two samples (N43 and N50). We investigated whether we could predict the three most important side effects for individuals from their frequency, severity and life impact. MSE is a 53-item measure with good reliability and validity. Poorer mental and physical health, but not psychotic symptoms, was related to side-effect burden. Seventy-nine percent of items were chosen as one of the three most important effects. Severity, impact and distress only predicted 'putting on weight' which was more distressing, more severe and had more life impact in those for whom it was most important. MSE is a self-report questionnaire that identifies reliably the side-effect burden as experienced by patients. Identifying key side effects important to patients can act as a starting point for joint decision making on the type and the dose of medication.

  7. The effect of Er on MSE measurements of q, a new technique for measuring Er, and a test of the neoclassical electric field

    International Nuclear Information System (INIS)

    Zarnstorff, M.C.; Synakowski, E.J.

    1996-10-01

    Previous analysis of motional-Stark Effect (MSE) data to measure the q-profile ignored contributions from the plasma electric field. The MSE measurements are shown to be sensitive to the electric field and require significant corrections for plasmas with large rotation velocities or pressure gradients. MSE measurements from rotating plasmas on the Tokamak Fusion Test Reactor (TFTR) confirm the significance of these corrections and verify their magnitude. Several attractive configurations are considered for future MSE-based diagnostics for measuring the plasma radial electric field. MSE data from TFTR is analyzed to determine the change in the radial electric field between two plasmas. The measured electric field quantitatively agrees with the predictions of neoclassical theory. These results confirm the utility of a MSE electric field measurement

  8. Evaluation of corrosion of metallic reinforcements and connections in MSE retaining walls.

    Science.gov (United States)

    2008-05-01

    Mechanically Stabilized Earth (MSE) retaining walls have become the dominant retained wall system on ODOT projects. The permanent MSE walls constructed on ODOT projects, in recent years, use metallic reinforcements and facing connections buried direc...

  9. Modeling and analysis to quantify MSE wall behavior and performance.

    Science.gov (United States)

    2009-08-01

    To better understand potential sources of adverse performance of mechanically stabilized earth (MSE) walls, a suite of analytical models was studied using the computer program FLAC, a numerical modeling computer program widely used in geotechnical en...

  10. Progress on the MSE diagnostic for ITER

    International Nuclear Information System (INIS)

    Lotte, Ph.; Giannella, R.; Von Hellermann, M.; Kuldkepp, M.; Rachlew, E.; Malaquias, A.; Costley, A.; Walker, C.

    2004-01-01

    The Motional Stark Effect (MSE) diagnostic is now considered as an essential diagnostic for an accurate determination of current profiles in tokamak discharges. It mainly allows a measurement of the direction of the total magnetic field, a very powerful constraint for the determination of the safety factor profile. The realisation of such a diagnostic on ITER implies to face new challenges, because of the bigger size of the machine and of its hard environment. Now, most of the foreseen difficulties have been examined, solutions envisaged, and we propose to review them in this paper. This article is divided into 3 parts: 1) principle of the MSE diagnostic and its feasibility at higher Lorentz electric fields, 2) spatial and time resolution of the diagnostic, and 3) the light collection system

  11. Nondestructive evaluation of mechanically stabilized earth walls with frequency-modulated continuous wave (FM-CW) radar.

    Science.gov (United States)

    2014-06-01

    Effective techniques for a nondestructive evaluation of mechanically stabilized earth (MSE) walls during normal operation : or immediately after an earthquake event are yet to be developed. MSE walls often have a rough surface finishing for the : pur...

  12. Analytical and Numerical Evaluation of Limit States of MSE Wall Structure

    Directory of Open Access Journals (Sweden)

    Drusa Marián

    2016-12-01

    Full Text Available Simplification of the design of Mechanically Stabilized Earth wall structures (MSE wall or MSEW is now an important factor that helps us not only to save a time and costs, but also to achieve the desired results more reliably. It is quite common way in practice, that the designer of a section of motorway or railway line gives order for design to a supplier of geosynthetics materials. However, supplier company has experience and skills, but a general designer does not review the safety level of design and its efficiency, and is simply incorporating into the overall design of the construction project. Actually, large number of analytical computational methods for analysis and design of MSE walls or similar structures are known. The problem of these analytical methods is the verification of deformations and global stability of structure. The article aims to clarify two methods of calculating the internal stability of MSE wall and their comparison with FEM numerical model. Comparison of design approaches allows us to draft an effective retaining wall and tells us about the appropriateness of using a reinforcing element.

  13. Route 22 Over Liberty Avenue and Conrail Hillside Township, Union County, Monitoring of Tensar MSE Walls

    Science.gov (United States)

    2011-12-01

    This report discusses the application of Tensar geogrids as the reinforcement elements in the : construction of mechanically stabilized earth (MSE) walls on the Route 22 over Conrail and Liberty : Avenue bridge replacement project in Hillside, NJ. As...

  14. Lateral resistance of piles near vertical MSE abutment walls.

    Science.gov (United States)

    2013-03-01

    Full scale lateral load tests were performed on eight piles located at various distances behind MSE walls. The objective of the testing was to determine the effect of spacing from the wall on the lateral resistance of the piles and on the force induc...

  15. Status of PEM-based polarimetric MSE development at KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Jinseok; Chung, Jinil; Oh, Seungtae; Ko, Wonha [National Fusion Research Institute, Daejeon (Korea, Republic of); Bock, Maarten de; Ong, Henry; Lange, Guido [Eindhoven University of Technology, Eindhoven (Netherlands)

    2014-10-15

    A multi-chord PEM (photo elastic modulator)-based polarimetric motional Stark effect (MSE) system is under development for the KSTAR tokamak. The conceptual design for the front optics was optimized to preserve not only the polarization state of the input light for the MSE measurements but also the signal intensity of the existing charge exchange spectroscopy (CES) system that will share the front optics with the MSE. The optics design incorporates how to determine the number of channels and the number of fibers for each channel. A dielectric coating will be applied on the mirror to minimize the relative reflectivity and the phase shift between the two orthogonal polarization components of the incident light. Lenses with low stress-birefringence constants will be adopted to minimize non-linear and random changes in the polarization through the lenses, which is a trade-off with the rather high Faraday rotation in the lenses because the latter effect is linear and can be relatively easily calibrated out. Intensive spectrum measurements and their comparisons with the simulated spectra are done to assist the design of the bandpass filter system that will also use tilting stages to remotely control the passband. Following the system installation in 2014, the MSE measurements are expected to be performed during the 2015 KSTAR campaign.

  16. Assessing corrosion of MSE wall reinforcement.

    Science.gov (United States)

    2010-09-01

    The primary objective of this study was to extract reinforcement coupons from select MSE walls and document the extent of corrosion. In doing this, a baseline has been established against which coupons extracted in the future can be compared. A secon...

  17. MHD marking using the MSE polarimeter optics in ILW JET plasmas

    CERN Document Server

    Reyes Cortes, S.; Alves, D.; Baruzzo, M.; Bernardo, J.; Buratti, P.; Coelho, R.; Challis, C.; Chapman, I.; Hawkes, N.; Hender, T.C.; Hobirk, J.; Joffrin, E.

    2016-01-01

    In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

  18. Intra-shot MSE Calibration Technique For LHCD Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Jinseok; Scott, Steve; Shiraiwa, Syun' ichi; Greenwald, Martin; Parker, Ronald; Wallace, Gregory

    2009-11-23

    The spurious drift in pitch angle of order several degrees measured by the Motional Stark Effect (MSE) diagnostic in the Alcator C-Mod tokamak1 over the course of an experimental run day has precluded direct utilization of independent absolute calibrations. Recently, the underlying cause of the drift has been identified as thermal stress-induced birefringence in a set of in-vessel lenses. The shot-to-shot drift can be avoided by using MSE to measure only the change in pitch angle between a reference phase and a phase of physical interest within a single plasma discharge. This intra-shot calibration technique has been applied to the Lower Hybrid Current Drive (LHCD) experiments and the measured current profiles qualitatively demonstrate several predictions of LHCD theory such as an inverse dependence of current drive efficiency on the parallel refractive index and the presence of off-axis current drive.

  19. Networks, Micro Small Enterprises (MSE'S) and Performance: the ...

    African Journals Online (AJOL)

    This paper examines the role of informal personal networks in determining. Micro Small Enterprises (MSE's) success in Kenya. It adopts the network perspective theoretical approach. Empirically, the paper finds that MSE's in. Kenya get around market failures and lack of formal institutions through entrepreneurial personal ...

  20. MSE observatory: a revised and optimized astronomical facility

    Science.gov (United States)

    Bauman, Steven E.; Angers, Mathieu; Benedict, Tom; Crampton, David; Flagey, Nicolas; Gedig, Mike; Green, Greg; Liu, Andy; Lo, David; Loewen, Nathan; McConnachie, Alan; Murowinski, Rick; Racine, René; Salmon, Derrick; Stiemer, Siegfried; Szeto, Kei; Wu, Di

    2016-07-01

    The Canada-France-Hawaii-Telescope Corporation (CFHT) plans to repurpose its observatory on the summit of Maunakea and operate a (60 segment) 11.25m aperture wide field spectroscopic survey telescope, the Maunakea Spectroscopic Explorer (MSE). The prime focus telescope will be equipped with dedicated instrumentation to take advantage of one of the best sites in the northern hemisphere and offer its users the ability to perform large surveys. Central themes of the development plan are reusing and upgrading wherever possible. MSE will reuse the CFHT site and build upon the existing observatory infrastructure, using the same building and telescope pier as CFHT, while minimizing environmental impact on the summit. MSE will require structural support upgrades to the building to meet the latest building seismic code requirements and accommodate a new larger telescope and upgraded enclosure. It will be necessary to replace the current dome since a larger slit opening is needed for a larger telescope. MSE will use a thermal management system to remove heat generated by loads from the building, flush excess heat from lower levels, and maintain the observing environment temperature. This paper describes the design approach for redeveloping the CFHT facility for MSE. Once the project is completed the new facility will be almost indistinguishable on the outside from the current CFHT observatory. Past experience and lessons learned from CFHT staff and the astronomical community will be used to create a modern, optimized, and transformative scientific data collecting machine.

  1. 172 Networks, Micro Small Enterprises (MSE'S) and Performance ...

    African Journals Online (AJOL)

    User

    Abeka, Evance Ochieng' - Dept. of Economics, School of Economics. & Business ... Abstract. This paper examines the role of informal personal networks in determining. Micro Small Enterprises (MSE's) success in Kenya. It adopts the network .... Social Network Approach looks at how network relationships influence small.

  2. Effects of molecule stabilization energies on radical reactions: G3 and G3(MP2) model chemistries applied to benzylic systems.

    Science.gov (United States)

    Rogers, Donald W; Zavitsas, Andreas A; Matsunaga, Nikita

    2009-11-05

    We have carried out G3 and G3(MP2) calculations of the molecule stabilization energies (MSEs) brought about by 11 common substituent groups in the meta and para positions of benzyl fluoride. We find that MSE is a function of the tendency of the substituent to donate or to withdraw electrons, such that a classic Hammett plot can be drawn. We propose that, in general, the direction of the benzylic Z-X dipole of YC6H4ZX is the major factor controlling the sign of the slope of Hammett plots of benzylic atom abstractions by radicals. When the Z-X dipole is pointed away from the substituted ring, electron withdrawing substituents destabilize the molecule, contributing to a decrease of the Z-X bond dissociation energy, and electron donating substituents stabilize it. The reverse is true when the dipole is reversed. This proposal is supported by 13C NMR results and by a survey of relevant benzylic and quasi-benzylic hydrogen or halogen atom abstractions studied experimentally. Calculations at the G3 level of theory demonstrate an increase in the bond dissociation energy of p-YC6H4CH2-H with increasing electron withdrawing ability of Y, contrary to results of previous lower level calculations. MSE values of substituted benzyl fluorides (p-YC6H4CH2F) correlate well with allylic MSE (trans-YCH=CHCH2F) and quantify the relative efficacy of transmission of electronic effects by vinylogy.

  3. MSE measurements for sawtooth and non-inductive current drive studies in KSTAR

    Science.gov (United States)

    Ko, J.; Park, H.; Bea, Y. S.; Chung, J.; Jeon, Y. M.

    2016-10-01

    Two major topics where the measurement of the magnetic-field-line rotational transform profiles in toroidal plasma systems include the long-standing issue of complete versus incomplete reconnection model of the sawtooth instability and the issue with future reactor-relevant tokamak devices in which non-inductive steady state current sustainment is essential. The motional Stark effect (MSE) diagnostic based on the photoelastic-modulator (PEM) approach is one of the most reliable means to measure the internal magnetic pitch, and thus the rotational transform, or its reciprocal (q), profiles. The MSE system has been commissioned for the Korea Superconducting Tokamak Advanced Research (KSTAR) along with the development of various techniques to minimize systematic offset errors such as Faraday rotation and mis-alignment of the bandpass filters. The diagnostic has revealed the central q is well correlated with the sawtooth oscillation, maintaining its value above unity during the MHD quiescent period and that the response of the q profile to external current drive such as electron cyclotron wave injection not only involves the local change of the pitch angle gradient but also a significant shift of the magnetic topology due to the wave energy transport. Work supported by the Ministry of Science, ICT and Future Planning, Korea.

  4. On the MSE Performance and Optimization of Regularized Problems

    KAUST Repository

    Alrashdi, Ayed

    2016-11-01

    The amount of data that has been measured, transmitted/received, and stored in the recent years has dramatically increased. So, today, we are in the world of big data. Fortunately, in many applications, we can take advantages of possible structures and patterns in the data to overcome the curse of dimensionality. The most well known structures include sparsity, low-rankness, block sparsity. This includes a wide range of applications such as machine learning, medical imaging, signal processing, social networks and computer vision. This also led to a specific interest in recovering signals from noisy compressed measurements (Compressed Sensing (CS) problem). Such problems are generally ill-posed unless the signal is structured. The structure can be captured by a regularizer function. This gives rise to a potential interest in regularized inverse problems, where the process of reconstructing the structured signal can be modeled as a regularized problem. This thesis particularly focuses on finding the optimal regularization parameter for such problems, such as ridge regression, LASSO, square-root LASSO and low-rank Generalized LASSO. Our goal is to optimally tune the regularizer to minimize the mean-squared error (MSE) of the solution when the noise variance or structure parameters are unknown. The analysis is based on the framework of the Convex Gaussian Min-max Theorem (CGMT) that has been used recently to precisely predict performance errors.

  5. Hemostatic chemical constituents from natural medicine Toddalia asiatica root bark by LC-ESI Q-TOF MSE

    OpenAIRE

    Zhang, Xiaoyan; Sun, Wenbo; Yang, Zhou; Liang, Yan; Zhou, Wei; Tang, Lei

    2017-01-01

    Background Toddalia asiatica root bark as an effective hemostatic natural medicine or Chinese materia medica was applied in China for long history, its complex drug action mechanisms and unclear substance basis have been constraining the development of this drug. Results An intelligentized strategy by LC-ESI Q-TOF MSE was presented in this study for rapid identification of hemostatic chemical constituents from this natural medicine. Chromatographic separation was performed on a C18 column (15...

  6. Stabilizing effect of epoxidized sunflower oil as a secondary stabilizer for Ca/Hg stabilized PVC

    Directory of Open Access Journals (Sweden)

    2008-01-01

    Full Text Available Unsaturated triglyceride oil sunflower was epoxidized and characterized by chemical and spectroscopic methods. Epoxidized sunflower oil (ESO was used as an organic thermal co-stabilizer for rigid poly(vinyl chloride (PVC in the presence of tricalcium dicitrate (Ca3(C6H5O72 and mercury (II acetate (Hg(CH3COO2. The thermo-oxidative degradation of PVC was studied in the presence of these ternary stabilizer systems at 170, 180, 190 and 200°C in N2 atmosphere. The effects of metal carboxylate combination Ca/Hg in the absence and in the presence of epoxidized sunflower oil on static heat treatment of PVC have been studied. The formation of polyene sequences was investigated by UV-visible and FT-IR spectroscopy and by comparing viscosity data obtained in the presence and in the absence of the additives. It was found that the additives retard the rate of degradation and reduce the extent of polymer chain scission associated with the thermal degradation of poly(vinyl chloride. Synergistic effects were found when stabilizer was blended in 50:50 weight ratios with either. It was found that ESO exerted a stabilizing effect on the degradation of PVC. The activation energy for degraded PVC in absence of stabilizers was 38.6 kJ•mol–1 and in the presence of Ca/Hg and Ca/Hg/ESO were 53.3 and 64.7 kJ•mol–1 respectively. In order of compare the efficiency of the epoxidized sunflower oil with these metal soap stabilizers, thermal stabilities were evaluated on the basis of evolved hydrogen chloride determined by conductometry technique and degree of discoloration are discussed.

  7. Magnetic field amplitude and pitch angle measurements using Spectral MSE on EAST

    Science.gov (United States)

    Liao, Ken; Rowan, William; Fu, Jia; Li, Ying-Ying; Lyu, Bo; Marchuk, Oleksandr; Ralchenko, Yuri

    2017-10-01

    We have developed the Spectral Motional Stark Effect technique for measuring magnetic field amplitude and pitch angle on EAST. The experiments were conducted using the tangential co-injection heating beam at A port and Beam Emission Spectroscopy array at D port. A spatial calibration of the observation channels was conducted before the campaign. As a first check, the measured magnetic field amplitude was compared to prediction. Since the toroidal field is dominant, we recovered the expected 1/R shape over the spatial range 1.75account the effect of the Lorentz field was used to predict the beam populations. The initial comparison is to an EFIT reconstruction. We are investigating sources of errors using a combination of simulations and calibrations arising from hardware non-idealities and approximations in the analysis. We are also investigating improvements in the EAST spectral MSE diagnostic. Supported by the U.S. DOE, Office of Fusion Energy Sciences under Award DE-SC0010500, National Magnetic Confinement Fusion Science Program of China under Grant No. 2015GB103003 and National Natural Science Foundation of China (No. 11605242).

  8. MSE spectrograph optical design: a novel pupil slicing technique

    Science.gov (United States)

    Spanò, P.

    2014-07-01

    The Maunakea Spectroscopic Explorer shall be mainly devoted to perform deep, wide-field, spectroscopic surveys at spectral resolutions from ~2000 to ~20000, at visible and near-infrared wavelengths. Simultaneous spectral coverage at low resolution is required, while at high resolution only selected windows can be covered. Moreover, very high multiplexing (3200 objects) must be obtained at low resolution. At higher resolutions a decreased number of objects (~800) can be observed. To meet such high demanding requirements, a fiber-fed multi-object spectrograph concept has been designed by pupil-slicing the collimated beam, followed by multiple dispersive and camera optics. Different resolution modes are obtained by introducing anamorphic lenslets in front of the fiber arrays. The spectrograph is able to switch between three resolution modes (2000, 6500, 20000) by removing the anamorphic lenses and exchanging gratings. Camera lenses are fixed in place to increase stability. To enhance throughput, VPH first-order gratings has been preferred over echelle gratings. Moreover, throughput is kept high over all wavelength ranges by splitting light into more arms by dichroic beamsplitters and optimizing efficiency for each channel by proper selection of glass materials, coatings, and grating parameters.

  9. Effect and Stability of Leadership Training.

    Science.gov (United States)

    Peterson, Peter B.

    The purpose of this study was to investigate the effect of U.S. Army Engineer Officer Candidate training and the stability of this training when measured again years after departure from Officer Candidate School. A self-description inventory was administered at the beginning of a 6-month training program, again near the end of the program, and…

  10. Usage-Centered Design Approach in Design of Malaysia Sexuality Education (MSE) Courseware

    Science.gov (United States)

    Chan, S. L.; Jaafar, A.

    The problems amongst juveniles increased every year, especially rape case of minor. Therefore, the government of Malaysia has introduced the National Sexuality Education Guideline on 2005. An early study related to the perception of teachers and students toward the sexuality education curriculum taught in secondary schools currently was carried out in 2008. The study showed that there are big gaps between the perception of the teachers and the students towards several issues of Malaysia sexuality education today. The Malaysia Sexuality Education (MSE) courseware was designed based on few learning theories approach. Then MSE was executed through a comprehensive methodology which the model ADDIE integrated with Usage-Centered Design to achieve high usability courseware. In conclusion, the effort of developing the MSE is hopefully will be a solution to the current problem that happens in Malaysia sexuality education now.

  11. Rf effects on plasma stability: Final report

    International Nuclear Information System (INIS)

    Krall, N.A.

    1986-12-01

    A program of study on the effect of high frequency waves on low frequency stability of plasma was concluded. The inclusion of electromagnetic modes completed the survey of mode types and wave number geometry, and a calculation in cylindrical geometry validated the slab model calculations. Application of the method to drift and trapped particle instabilities confirmed the relevance of rf processes to tokamaks and ionospheric plasmas, in addition to the mirror devices for which they were originally explored

  12. Effect of core stability exercise on postural stability in children with Down syndrome

    OpenAIRE

    Sobhy M. Aly

    2016-01-01

    Down syndrome is one of the commonest causes of developmental delay in children. Postural stability problems often exist with Down syndrome. To investigate the effect of core stability exercises on postural stability in children with down syndrome. Thirty children (21 boys and 9 girls) with down syndrome, with ages ranged from 6 to 10 years were participated in this study. They were assigned randomlyinto study and control group. Study group received core stability exercises and conventional p...

  13. Effect of Viscosity on Liquid Curtain Stability

    Science.gov (United States)

    Mohammad Karim, Alireza; Suszynski, Wieslaw; Francis, Lorraine; Carvalho, Marcio; Dow Chemical Company Collaboration; PUC Rio Collaboration; University of Minnesota, Twin Cities Collaboration

    2016-11-01

    The effect of viscosity on the stability of Newtonian liquid curtains was explored by high-speed visualization. Glycerol/water solutions with viscosity ranging from 19.1 to 210 mPa.s were used as coating liquids. The experimental set-up used a slide die delivery and steel tube edge guides. The velocity along curtain at different positions was measured by tracking small particles at different flow conditions. The measurements revealed that away from edge guides, velocity is well described by free fall effect. However, close to edge guides, liquid moves slower, revealing formation of a viscous boundary layer. The size of boundary layer and velocity near edge guides are strong function of viscosity. The critical condition was determined by examining flow rate below which curtain broke. Curtain failure was initiated by growth of a hole within liquid curtain, close to edge guides. Visualization results showed that the hole forms in a circular shape then becomes elliptical as it grows faster in vertical direction compared to horizontal direction. As viscosity rises, minimum flow rate for destabilization of curtain increased, indicating connection between interaction with edge guides and curtain stability. We would like to acknowledge the financial support from the Dow Chemical Company.

  14. Min-Max MSE-based Interference Alignment for Transceiver Designs in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    H. H. Kha

    2017-04-01

    Full Text Available This paper is concerned with an optimal design of the precoders and receive filters for cognitive radio (CR networks in which multiple secondary users (SUs share the same frequency band with multiple primary users (PUs. To cope with interference and to achieve fairness among users, we develop an interference alignment (IA scheme by minimizing the maximum mean squared error (Min-Max MSE of the received signals. Since the Min-Max MSE design problems are nonconvex in the design matrix variables of the precoders and receive filters, we develop an alternating optimization algorithm with provable convergence to iteratively find the optimal solutions. In each iteration, the precoder design problems can be recast as second order cone program (SOCP while the optimal receive filters can be derived in closed-form solutions. Finally, numerical results are provided to demonstrate the superiority of the proposed method as compared to previous work in terms of the information rate and bit error rate.

  15. Weighted-MSE based on saliency map for assessing video quality of H.264 video streams

    Science.gov (United States)

    Boujut, H.; Benois-Pineau, J.; Hadar, O.; Ahmed, T.; Bonnet, P.

    2011-01-01

    Human vision system is very complex and has been studied for many years specifically for purposes of efficient encoding of visual, e.g. video content from digital TV. There have been physiological and psychological evidences which indicate that viewers do not pay equal attention to all exposed visual information, but only focus on certain areas known as focus of attention (FOA) or saliency regions. In this work, we propose a novel based objective quality assessment metric, for assessing the perceptual quality of decoded video sequences affected by transmission errors and packed loses. The proposed method weights the Mean Square Error (MSE), Weighted-MSE (WMSE), according to the calculated saliency map at each pixel. Our method was validated trough subjective quality experiments.

  16. Effects of joint stabilizers on proprioception and stability: A systematic review and meta-analysis.

    Science.gov (United States)

    Ghai, Shashank; Driller, Matthew; Ghai, Ishan

    2017-05-01

    The current review and meta-analysis systematically investigated the effect of joint stabilizers on proprioception, postural stability, and neurological activity. Systematic identification of published literature was performed on online databases; Scopus, PEDro, SportDiscus, and EMBASE, followed by a critical PEDro methodological quality appraisal. Data from the studies were extracted and summarized in a tabular format. Of 2954 records, 50 studies, involving 1443 participants met our inclusion criteria. In the included studies, 60% of studies reported significant enhancements (p  0.05) and 21% of studies reported no effects of joint stabilizers on proprioception and/or postural stability. Meta-analysis of pooled studies demonstrated beneficial effects of joint stabilizers on the knee (95% CI: 0.35°-0.61°) and ankle (at 10: 0.1°-0.65°) joint proprioception, and negligible effects on postural stability (-0.28°-0.19°). The pooled evidence suggests that application of joint stabilizers enhances joint proprioception and stability by not merely altering the mechanical stability of the underlying musculoskeletal structures but by also causing subtle changes in cerebral haemodynamics and musculoskeletal activation. These findings support clinical implications of joint stabilizers as a prophylactic and rehabilitation measure in modern sports and rehabilitation settings. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Report on single beam stability - coherent effects

    International Nuclear Information System (INIS)

    Brouzet, E.; Gareyte, J.; Hofmann, A.; Laclare, J.C.; Leleux, G.; Miles, J.; Schindl, K.H.

    1980-01-01

    Group 1A was concerned with single beam stability, coherent effects. Theory is available. Most of the material for this work was drawn from F.J. Sacherer theory which has been left in reasonably good shape in the sense that given any coupling impedance, its effect on the beam can be estimated. The EBI computer program was extensively used in this respect. We still lack thorough knowledge of the SPS coupling impedance. Accordingly our results rest on a model. This model should be too unrealistic since it originates from various data of the SPS and other machines. Nevertheless any complementary information about the SPS impedance would be welcome. Broad-band impedance and parasitic effects on transverse and longitudinal motions will be reviewed. We shall mainly focus on the 270 GeV case with six equidistant bunches and 10 11 particles per bunch. For other schemes results can be obtained in a similar fashion. Some relevant figures will be given for the situation at injection. (orig.)

  18. Effects of core muscle stability training on the weight distribution and stability of the elderly

    OpenAIRE

    Kang, Kwon-Young

    2015-01-01

    [Purpose] This study investigated the effects of core muscle stability training on the weight distribution and stability of the elderly. [Subjects and Methods] Thirty elderly persons were randomly divided into an experimental group which performed core strengthening exercises, and a control group which performed standard strengthening exercises for 8 weeks. A Tetrax Interactive Balance System was used to evaluate the weight distribution index (WDI) and the stability index (SI). [Results] The ...

  19. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  20. Effects of phosphoramides on wood dimensional stability

    Science.gov (United States)

    Hong-Lin. Lee; George C. Chen; Roger M. Rowell

    2000-01-01

    To evaluate the dimensional stability of phosphoramide-reacted wood, wood was reacted with a mixture which was derived from compounding phosphorus pentoxide and each of 12 amines including alkyl, halophenyl, and phenyl amines in N,N-dimethylformamide. Dimensional stability of such reacted wood was analyzed by antishrink efficiency (ASE) using the water-soak method....

  1. Effect of core stability exercise on postural stability in children with Down syndrome

    Directory of Open Access Journals (Sweden)

    Sobhy M. Aly

    2016-10-01

    Full Text Available Down syndrome is one of the commonest causes of developmental delay in children. Postural stability problems often exist with Down syndrome. To investigate the effect of core stability exercises on postural stability in children with down syndrome. Thirty children (21 boys and 9 girls with down syndrome, with ages ranged from 6 to 10 years were participated in this study. They were assigned randomlyinto study and control group. Study group received core stability exercises and conventional physical therapy program while control group received Conventional physical therapy program. The duration of treatment was 8 weeks. Postural stability was evaluated pre and post treatment by Biodex *Balance System. There was a significant decrease in anteroposterior, mediolateral, and overall stability indices of the study group compared with control group post treatment (p <0.001. Both groups showed a significant decrease in anteroposterior, mediolateral, and overall stability indices post treatment compared with pre treatment (p < 0.001. Eight weeks of core stability exercises is effective in improving postural stabilityand balance of children with Down syndrome. Core stability exercises should be considered as important part of the rehabilitation program for childrenwith Down syndrome.

  2. Analysis of the water dynamics for the MSE-COIL and theMST-COIL

    CERN Document Server

    Massidda, L; Kadi, Y; Balhan, B

    2005-01-01

    In this report, we present the technical specification for the numerical model and the study of the acoustic wave propagation in the water tubes of the extraction septum magnet (MSE) and the thin magnetic septum (MST) in the event of an asynchronous firing of the extraction kickers (MKE). The deposited energy densities, estimated by the high-energy particle transport code FLUKA, were converted to internal heat generation rates according to the time dependence of the extracted beam. The transient response to this thermal load was obtained by simulating power deposition and acoustic wave propagation by the spectral-element code ELSE.

  3. Life beyond MSE and R2 — improving validation of predictive models with observations

    Science.gov (United States)

    Papritz, Andreas; Nussbaum, Madlene

    2017-04-01

    Machine learning and statistical predictive methods are evaluated by the closeness of predictions to observations of a test dataset. Common criteria for rating predictive methods are bias and mean square error (MSE), characterizing systematic and random prediction errors. Many studies also report R2-values, but their meaning is not always clear (correlation between observations and predictions or MSE skill score; Wilks, 2011). The same criteria are also used for choosing tuning parameters of predictive procedures by cross-validation and bagging (e.g. Hastie et al., 2009). For evident reasons, atmospheric sciences have developed a rich box of tools for forecast verification. Specific criteria have been proposed for evaluating deterministic and probabilistic predictions of binary, multinomial, ordinal and continuous responses (see reviews by Wilks, 2011, Jollie and Stephenson, 2012 and Gneiting et al., 2007). It appears that these techniques are not very well-known in the geosciences community interested in machine learning. In our presentation we review techniques that offer more insight into proximity of data and predictions than bias, MSE and R2 alone. We mention here only examples: (i) Graphing observations vs. predictions is usually more appropriate than the reverse (Piñeiro et al., 2008). (ii) The decomposition of the Brier score score (= MSE for probabilistic predictions of binary yes/no data) into reliability and resolution reveals (conditional) bias and capability of discriminating yes/no observations by the predictions. We illustrate the approaches by applications from digital soil mapping studies. Gneiting, T., Balabdaoui, F., and Raftery, A. E. (2007). Probabilistic forecasts, calibration and sharpness. Journal of the Royal Statistical Society Series B, 69, 243-268. Hastie, T., Tibshirani, R., and Friedman, J. (2009). The Elements of Statistical Learning; Data Mining, Inference and Prediction. Springer, New York, second edition. Jolliffe, I. T. and

  4. Atomic physics effects on dissipative toroidal drift wave stability

    International Nuclear Information System (INIS)

    Beer, M.A.; Hahm, T.S.

    1992-02-01

    The effects of atomic physics processes such as ionization, charge exchange, and radiation on the linear stability of dissipative drift waves are investigated in toroidal geometry both numerically and analytically. For typical TFTR and TEXT edge parameters, overall linear stability is determined by the competition between the destabilizing influence of ionization and the stabilizing effect due to the electron temperature gradient. An analytical expression for the linear marginal stability condition, η e crit , is derived. The instability is most likely to occur at the extreme edge of tokamaks with a significant ionization source and a steep electron density gradient

  5. Effect of Chemical Stabilizers in Silver Nanoparticle Suspensions on Nanotoxicity

    International Nuclear Information System (INIS)

    Bae, Eun Joo; Park, Hee Jin; Park, Jun Su; Yoon, Je Yong; Yi, Jong Heop; Kim, Young Hun; Choi, Kyung Hee

    2011-01-01

    Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers

  6. Effect of Chemical Stabilizers in Silver Nanoparticle Suspensions on Nanotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Eun Joo; Park, Hee Jin; Park, Jun Su; Yoon, Je Yong; Yi, Jong Heop [Seoul National University, Seoul (Korea, Republic of); Kim, Young Hun [Kwangwoon University, Seoul (Korea, Republic of); Choi, Kyung Hee [National Institute of Environmental Research, Incheon (Korea, Republic of)

    2011-02-15

    Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers.

  7. Salmon calcitonin: conformational changes and stabilizer effects

    Directory of Open Access Journals (Sweden)

    Shan-Yang Lin

    2015-11-01

    Full Text Available The therapeutic activity of peptides or protein drugs is highly dependent on their conformational structure. The protein structure is flexible and responds to external conditions, which may compromise the protein's native conformation and influence its physical and chemical stability. The physical and chemical stability of peptides or protein drugs are important characteristics of biopharmaceutical products. Calcitonin (CT is a polypeptide hormone that participates in diverse physiological functions in humans; therefore, it is a potentially useful protein for investigations of different aspects of pharmacology and drug delivery systems. Of the different types of CT available for clinical use, salmon CT (sCT is one of the most potent. In this review article, the commercially available sCT was selected as a suitable peptide candidate for the discussion of its stability and conformational changes in the aqueous and solid states using Fourier transform infrared (FTIR spectroscopic analysis under different external conditions, including pH, temperature, drying method, and added excipients. Particularly, excipients that have been optimized as stabilizers of sCT in aqueous solution and as lyophilized and spray-dried drug formulations are also discussed.

  8. Power distribution effects on boiling water reactor stability

    International Nuclear Information System (INIS)

    Damiano, B.; March-Leuba, J.

    1989-01-01

    The work presented in this paper deals with the effects of spatial power distributions on the stability of boiling water reactors (BWRs). It is shown that a conservative power distribution exists for which the stability is minimal. These results are relevant because they imply that bounding stability calculations are possible and, thus, a worst-possible scenario may be defined for a particular BWR geometry. These bounding calculations may, then, be used to determine the maximum expected limit-cycle peak powers

  9. Effect of training on the slackline on postural stabilization

    OpenAIRE

    Brožková, Martina

    2015-01-01

    Title: Effect of training on the slackline on postural stabilization Objectives: The aim of this study was to determine whether training on the slackline affects postural stabilization of sample of sport aktive population. The aim was to detect changes in postural stabilization immediately after the first training (30 minutes) on the slackline and after long-term training on the slackline. Another aim was to determine to what extent influenced measurement on Posturomed itself postural stabili...

  10. Understanding the stabilizing effects of IT on organizations

    NARCIS (Netherlands)

    Boogaard, Martin; Huysman, Marleen H.

    1994-01-01

    In the literature, two distinct ways in which the application of IT stabilizes organizations are indicated. The first stabilizing effect concerns the difficult, time-consuming, and costly adjustments of existing ISs when changes to ISs have to be made. Consequently, when circumstances change

  11. Effects of attentional focus on walking stability in elderly

    NARCIS (Netherlands)

    de Melker Worms, Jonathan L.A.; Stins, John F.; van Wegen, Erwin E.H.; Verschueren, Sabine M.P.; Beek, Peter J.; Loram, Ian D.

    2017-01-01

    Introduction Balance performance in the elderly is related to psychological factors such as attentional focus. We investigated the effects of internal vs. external focus of attention and fall history on walking stability in healthy older adults. Method Walking stability of twenty-eight healthy older

  12. Stabilizing Agents for Drug Nanocrystals: Effect on Bioavailability

    Directory of Open Access Journals (Sweden)

    Annika Tuomela

    2016-05-01

    Full Text Available Drug nanocrystals are a versatile option for drug delivery purposes, and while the number of poorly soluble drug materials is all the time increasing, more research in this area is performed. Drug nanocrystals have a simple structure—a solid drug core is surrounded by a layer of stabilizing agent. However, despite the considerably simple structure, the selection of an appropriate stabilizer for a certain drug can be challenging. Mostly, the stabilizer selection is based purely on the requirement of physical stability, e.g., maintaining the nanosized particle size as long as possible after the formation of drug nanocrystals. However, it is also worth taking into account that stabilizer can affect the bioavailability in the final formulation via interactions with cells and cell layers. In addition, formation of nanocrystals is only one process step, and for the final formulation, more excipients are often added to the composition. The role of the stabilizers in the final formulation can be more than only stabilizing the nanocrystal particle size. A good example is the stabilizer’s role as cryoprotectant during freeze drying. In this review, the stabilizing effect, role of stabilizers in final nanocrystalline formulations, challenges in reaching in vitro–in vivo correlation with nanocrystalline products, and stabilizers’ effect on higher bioavailability are discussed.

  13. Effects of core muscle stability training on the weight distribution and stability of the elderly.

    Science.gov (United States)

    Kang, Kwon-Young

    2015-10-01

    [Purpose] This study investigated the effects of core muscle stability training on the weight distribution and stability of the elderly. [Subjects and Methods] Thirty elderly persons were randomly divided into an experimental group which performed core strengthening exercises, and a control group which performed standard strengthening exercises for 8 weeks. A Tetrax Interactive Balance System was used to evaluate the weight distribution index (WDI) and the stability index (SI). [Results] The experimental group showed a significant improvement in terms of WDI and the SI. However, the control group showed no significant improvement in either. [Conclusion] Core muscle stability training should be considered as a therapeutic method for the elderly to improve their WDI, and SI, and as a fall prevention measure.

  14. [Stabilization and long-term effect of chromium contaminated soil].

    Science.gov (United States)

    Wang, Jing; Luo, Qi-Shi; Zhang, Chang-Bo; Tan, Liang; Li, Xu

    2013-10-01

    Short-term (3 d and 28 d) and long-term (1 a) stabilization effects of Cr contaminated soil were investigated through nature curing, using four amendments including ferrous sulfide, ferrous sulfate, zero-valent iron and sodium dithionite. The results indicated that ferrous sulfide and zero-valent iron were not helpful for the stabilization of Cr(VI) when directly used because of their poor solubility and immobility. Ferrous sulfate could effectively and rapidly decrease total leaching Cr and Cr(VI) content. The stabilization effect was further promoted by the generation of iron hydroxides after long-term curing. Sodium dithionite also had positive effect on soil stabilization. Appropriate addition ratio of the two chemicals could help maintain the soil pH in range of 6-8.

  15. Numerical Study on Soil Arching Effects of Stabilizing Piles

    OpenAIRE

    Fan, Fusong; Chen, Guangqi; Hu, Xinli; Wang, Wei

    2015-01-01

    The Soil arching effect, the transfer of soil pressure from the yielding soil to the piles support, is a phenomena commonly encountered in geotechnical engineering for stabilizing landslides. In this paper, the (finite element method) FEM and (discontinuous deformation analysis) DDA were used to study on the soil arching effects of stabilizing piles in landslides. This paper proposes a method for two dimensional numerical simulation to perform three dimensional soil-pile interaction so that t...

  16. Survivin counteracts the therapeutic effect of microtubule de-stabilizers by stabilizing tubulin polymers

    Directory of Open Access Journals (Sweden)

    Hsieh Hsing-Pang

    2009-07-01

    Full Text Available Abstract Background Survivin is a dual function protein. It inhibits the apoptosis of cells by inhibiting caspases, and also promotes cell growth by stabilizing microtubules during mitosis. Over-expression of survivin has been demonstrated to induce drug-resistance to various chemo-therapeutic agents such as cisplatin (DNA damaging agent and paclitaxel (microtubule stabilizer in cancers. However, survivin-induced resistance to microtubule de-stabilizers such as Vinca alkaloids and Combretastatin A-4 (CA-4-related compounds were seldom demonstrated in the past. Furthermore, the question remains as to whether survivin plays a dominant role in processing cytokinesis or inhibiting caspases activity in cells treated with anti-mitotic compounds. The purpose of this study is to evaluate the effect of survivin on the resistance and susceptibility of human cancer cells to microtubule de-stabilizer-induced cell death. Results BPR0L075 is a CA-4 analog that induces microtubule de-polymerization and subsequent caspase-dependent apoptosis. To study the relationship between the expression of survivin and the resistance to microtubule de-stabilizers, a KB-derived BPR0L075-resistant cancer cell line, KB-L30, was generated for this study. Here, we found that survivin was over-expressed in the KB-L30 cells. Down-regulation of survivin by siRNA induced hyper-sensitivity to BPR0L075 in KB cells and partially re-stored sensitivity to BPR0L075 in KB-L30 cells. Western blot analysis revealed that down-regulation of survivin induced microtubule de-stabilization in both KB and KB-L30 cells. However, the same treatment did not enhance the down-stream caspase-3/-7 activities in BPR0L075-treated KB cells. Translocation of a caspase-independent apoptosis-related molecule, apoptosis-inducing factor (AIF, from cytoplasm to the nucleus was observed in survivin-targeted KB cells under BPR0L075 treatment. Conclusion In this study, survivin plays an important role in the

  17. Longitudinal static stability requirements for wing in ground effect vehicle

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2015-03-01

    Full Text Available The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

  18. Effects of Initial Stance of Quadruped Trotting on Walking Stability

    Directory of Open Access Journals (Sweden)

    Peisun Ma

    2008-11-01

    Full Text Available It is very important for quadruped walking machine to keep its stability in high speed walking. It has been indicated that moment around the supporting diagonal line of quadruped in trotting gait largely influences walking stability. In this paper, moment around the supporting diagonal line of quadruped in trotting gait is modeled and its effects on body attitude are analyzed. The degree of influence varies with different initial stances of quadruped and we get the optimal initial stance of quadruped in trotting gait with maximal walking stability. Simulation results are presented.

  19. Boiling water reactor stability revisited: The effects of flashing

    Energy Technology Data Exchange (ETDEWEB)

    Yadigaroglu, G. [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH, ETH-Zentrum, CLT-C1, CH-8092 Zurich (Switzerland)]. E-mail: yadi@ethz.ch; Askari, B. [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH, ETH-Zentrum, CLT-C1, CH-8092 Zurich (Switzerland)

    2005-05-01

    There are numerous investigations of two-phase flow stability with particular emphasis to BWR stability; these have become increasingly sophisticated and complete over the years. The basic features of a new development and frequency-domain code capable of considering all the channels (bundles) in a BWR, flashing of the coolant at low pressure, full coupling with 3D, two-group neutronics, etc. are described. The basic thermal-hydraulic model is used to study the effects of flashing on stability in a BWR-like channel. The behavior of the channel is highly dynamic. Contrary to what could have been intuitively guessed, the effect of flashing is stabilizing; the reasons and mechanisms leading to this are discussed.

  20. Boiling water reactor stability revisited: The effects of flashing

    International Nuclear Information System (INIS)

    Yadigaroglu, G.; Askari, B.

    2005-01-01

    There are numerous investigations of two-phase flow stability with particular emphasis to BWR stability; these have become increasingly sophisticated and complete over the years. The basic features of a new development and frequency-domain code capable of considering all the channels (bundles) in a BWR, flashing of the coolant at low pressure, full coupling with 3D, two-group neutronics, etc. are described. The basic thermal-hydraulic model is used to study the effects of flashing on stability in a BWR-like channel. The behavior of the channel is highly dynamic. Contrary to what could have been intuitively guessed, the effect of flashing is stabilizing; the reasons and mechanisms leading to this are discussed

  1. The effects of mercury on genomic stability in corn

    Science.gov (United States)

    Taşpınar, Mahmut Sinan; Sıǧmaz, Burcu; Aǧar, Güleray; Aydın, Murat

    2017-04-01

    It is a true that heavy metals have an effect plant species like affecting all of the living organisms into the existing environments. Heavy metals have hazardous effects on living organism. Several plant species have been used bio-indicators in order to determine the effects on genetic toxicity of heavy metal pollution so far. The aim of this paper detects the effects of Mercury chloride (HgCl2) were investigated on genetic stability/or DNA damage in maize seedlings. The results showed that all mercury doses used cause a decrease in the genomic template stability, while they cause an increase in the RAPDs profile changes (DNA damage).

  2. [Rapidly identify oligosaccharides in Morinda officinalis by UPLC-Q-TOF-MSE].

    Science.gov (United States)

    Hao, Qing-Xiu; Kang, Li-Ping; Zhu, Shou-Dong; Yu, Yi; Hu, Ming-Hua; Ma, Fang-Li; Zhou, Jie; Guo, Lan-Ping

    2018-03-01

    In this paper, an approach was applied for separation and identification of oligosaccharides in Morinda officinalis How by Ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) with collision energy. The separation was carried out on an ACQUITY UPLC BEH Amide C₁₈(2.1mm×100 mm,1.7 μm) with gradient elution using acetonitrile(A) and water(B) containing 0.1% ammonia as mobile phase at a flow rate of 0.2 mL·min⁻¹. The column temperature was maintained at 40 °C. The information of accurate mass and characteristic fragment ion were acquired by MSE in ESI negative mode in low and high collision energy. The chemical structures and formula of oligosaccharides were obtained and identified by the software of UNIFI and Masslynx 4.1 based on the accurate mass, fragment ions, neutral losses, mass error, reference substance, isotope information, the intensity of fragments, and retention time. A total of 19 inulin oligosaccharide structures were identified including D(+)-sucrose, 1-kestose, nystose, 1F-fructofuranosyl nystose and other inulin oligosaccharides (DP 5-18). This research provided important information about the inulin oligosaccharides in M. officinalis. The results would provide scientific basis for innovative utilization of M. officinalis. Copyright© by the Chinese Pharmaceutical Association.

  3. The effects of abdominal muscle coactivation on lumbar spine stability.

    Science.gov (United States)

    Gardner-Morse, M G; Stokes, I A

    1998-01-01

    A biomechanical model of the lumbar spine was used to calculate the effects of abdominal muscle coactivation on spinal stability. To estimate the effects of abdominal muscle coactivation on lumbar spine stability, muscle fatigue rate, and lumbar spine compression forces. The activation of human trunk muscles has been found to involve coactivation of antagonistic muscles, which has not been adequately predicted by biomechanical models. Antagonistic activation of abdominal muscles might produce flexion moments resulting from abdominal pressurization. Qualitatively, antagonistic activity also has been attributed to the need to stabilize the spine. Spinal loads and spinal stability were calculated for maximum and submaximum (40%, 60% and 80%) efforts in extension and lateral bending using a previously published, anatomically realistic biomechanical model of the lumbar spine and its musculature. Three different antagonistic abdominal muscle coactivation patterns were imposed, and results were compared with those found in a model with no imposed coactivation. Results were quantified in terms of the sum of cubed muscle stresses (sigma sigma m3, which is related to the muscle fatigue rate), the maximum compressive loading on the lumbar spine, and the critical value of the muscle stiffness parameter (q) required for the spine to be stable. Forcing antagonistic coactivation increased stability, but at the cost of an increase in sigma sigma m3 and a small increase in maximum spinal compression. These analyses provide estimates of the effects of antagonistic abdominal muscle coactivation, indicating that its probable role is to stabilize the spine.

  4. Aeroelastic effects on stability and control of hingeless rotor helicopters

    Science.gov (United States)

    Celi, Roberto

    1988-01-01

    The combined effect of torsional flexibility and offset of the aerodynamic center relative to the elastic axis on the stability and control of a hingeless rotor helicopter in forward flight is studied in this paper. The aeroelastic model of the blade is based on fully coupled flap-lag-torsion equations of motion, which include kinematic nonlinearities due to moderate deflections. The equations are discretized using a finite element Galerkin method in space, and a classical Galerkin method in time. The vehicle trim calculations are coupled to the blade aeroelastic response calculations. Quasilinearization is used to compute aeroelastic stability. Reducing torsional stiffness and moving the elastic axis ahead of the aerodynamic center strongly stabilizes the phugoid mode without reducing control sensitivity. Aeroelastic stability calculations must accompany flight dynamics calculations to prevent aeroelastic instabilities that might easily go undetected.

  5. Stability-increasing effects of anthocyanin glycosyl acylation.

    Science.gov (United States)

    Zhao, Chang-Ling; Yu, Yu-Qi; Chen, Zhong-Jian; Wen, Guo-Song; Wei, Fu-Gang; Zheng, Quan; Wang, Chong-De; Xiao, Xing-Lei

    2017-01-01

    This review comprehensively summarizes the existing knowledge regarding the chemical implications of anthocyanin glycosyl acylation, the effects of acylation on the stability of acylated anthocyanins and the corresponding mechanisms. Anthocyanin glycosyl acylation commonly refers to the phenomenon in which the hydroxyl groups of anthocyanin glycosyls are esterified by aliphatic or aromatic acids, which is synthetically represented by the acylation sites as well as the types and numbers of acyl groups. Generally, glycosyl acylation increases the in vitro and in vivo chemical stability of acylated anthocyanins, and the mechanisms primarily involve physicochemical, stereochemical, photochemical, biochemical or environmental aspects under specific conditions. Additionally, the acylation sites as well as the types and numbers of acyl groups influence the stability of acylated anthocyanins to different degrees. This review could provide insight into the optimization of the stability of anthocyanins as well as the application of suitable anthocyanins in food, pharmaceutical and cosmetic industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Aging effects on vertical graphene nanosheets and their thermal stability

    Science.gov (United States)

    Ghosh, S.; Polaki, S. R.; Ajikumar, P. K.; Krishna, N. G.; Kamruddin, M.

    2018-03-01

    The present study investigates environmental aging effects and thermal stability of vertical graphene nanosheets (VGN). Self-organized VGN is synthesized by plasma enhanced chemical vapor deposition and exposed to ambient conditions over 6-month period to examine its aging behavior. A systematic inspection is carried out on morphology, chemical structure, wettability and electrical property by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, water contact angle and four-probe resistivity measurements at regular intervals, respectively. Detailed microscopic and spectroscopic analysis substantiated the retention of graphitic quality and surface chemistry of VGN over the test period. An unchanged sheet resistance and hydrophobicity reveals its electrical and wetting stability over the time, respectively. Thermogravimetric analysis ensures an excellent thermal stability of VGN up to 575 °C in ambient atmosphere. These findings of long-term morphological, structural, wetting, electrical and thermal stability of VGN validate their potential utilization for the next-generation device applications.

  7. Quantifying Effectiveness of Streambank Stabilization Practices on Cedar River, Nebraska

    Directory of Open Access Journals (Sweden)

    Naisargi Dave

    2017-11-01

    Full Text Available Excessive sediment is a major pollutant to surface waters worldwide. In some watersheds, streambanks are a significant source of this sediment, leading to the expenditure of billions of dollars in stabilization projects. Although costly streambank stabilization projects have been implemented worldwide, long-term monitoring to quantify their success is lacking. There is a critical need to document the long-term success of streambank restoration projects. The objectives of this research were to (1 quantify streambank retreat before and after the stabilization of 18 streambanks on the Cedar River in North Central Nebraska, USA; (2 assess the impact of a large flood event; and (3 determine the most cost-efficient stabilization practice. The stabilized streambanks included jetties (10, rock-toe protection (1, slope reduction/gravel bank (1, a retaining wall (1, rock vanes (2, and tree revetments (3. Streambank retreat and accumulation were quantified using aerial images from 1993 to 2016. Though streambank retreat has been significant throughout the study period, a breached dam in 2010 caused major flooding and streambank erosion on the Cedar River. This large-scale flood enabled us to quantify the effect of one extreme event and evaluate the effectiveness of the stabilized streambanks. With a 70% success rate, jetties were the most cost-efficient practice and yielded the most deposition. If minimal risk is unacceptable, a more costly yet immobile practice such as a gravel bank or retaining wall is recommended.

  8. Effect of Amphiphilic Alkyl Chain Length Upon Purified LATEX Stability

    International Nuclear Information System (INIS)

    Amira Amir Hassan; Amir Hashim Mohd Yatim

    2015-01-01

    Rubber particles in purified latex (PL) are stabilized by a film of protein and fatty acid soap (surfactant). Saturated straight-chain fatty acid soaps can assist an enhancement of latex stability. However, whether the alkyl chain length plays an important role in increasing the stability is still an issue. The aim of this study is to investigate the effect of alkyl chain length of anionic surfactant on the stability of purified latex. The fatty acid soap of decanoate (9), laurate (11), sodium dodecyl sulphate (SDS) (12) and palmitate (15) were used. The numbers in parentheses indicating the number of carbon present in alkyl chain of the soap. The results showed that the impact of alkyl chain length on the stability of latex is in the order of laurate > decanoate > SDS > palmitate > purified latex accordingly. The alkyl chain length does giving a significant effect on latex stability after longer stirring time. The particle size of latex with the presence of surfactant is greater compare to a single particle itself due to extension of particles diameter. Thus suitable interaction of the nonpolar tail of surfactant with the hydrophobic regions of latex surface played a major role in maintaining a stable latex system. (author)

  9. Cardiovascular Effects of Antidepressants and Mood Stabilizers

    Directory of Open Access Journals (Sweden)

    Javad Maleki

    2007-09-01

    Full Text Available  Depression is a serious disorder in today’s society, with the estimates of lifetime prevalence being as high as 21% of the general population in some developed countries. As defined by the American Psychiatric Association, depression is a heterogeneous disorder often manifested with symptoms at the psychological, behavioral, and physiological levels. Such patients are often reluctant to take synthetic antidepressants in their appropriate doses due to their anticipated side effects including inability to drive a car, dry mouth, constipation, and sexual dysfunction. As a therapeutic alternative, effective herbal drugs may offer advantages in terms of safety and tolerability, possibly also improving patient compliance. The advent of the first antidepressants, Monoamine Oxidase Inhibitors (MAOIs and Tricyclic Antidepressants (TCAs, in the 1950s and 1960s represented a dramatic leap forward in the clinical management of depression. The subsequent development of the Selective Serotonin Reuptake Inhibitors (SSRIs and the Serotonin Norepinephrine Reuptake Inhibitor (SNRI venlafaxine in the past decade and a half has greatly enhanced the treatment of depression by offering patients medications that are as effective as the older agents but are generally more tolerable and safer in an overdose. The introduction of atypical antidepressants, such as bupropion, nefazadone, and mirtazapine, has added substantially to the available pharmacopoeia for depression. Nonetheless, rates of remission tend to be low and the risk of relapse and recurrence remains high. One of the concerns regarding the safety of antidepressant is its potential risk of cardiotoxicity and cardiovascular side effects. In this review, we will focus on the cardiovascular side effects of different types of antidepressants.

  10. Cardiovascular Effects of Antidepressants and Mood Stabilizers

    Directory of Open Access Journals (Sweden)

    Shahin Akhondzadeh

    2007-08-01

    Full Text Available Depression is a serious disorder in today’s society, with the estimates of lifetime prevalence being as high as 21% of the general population in some developed countries. As defined by the American Psychiatric Association, depression is a heterogeneous disorder often manifested with symptoms at the psychological, behavioral, and physiological levels. Such patients are often reluctant to take synthetic antidepressants in their appropriate doses due to their anticipated side effects including inability to drive a car, dry mouth, constipation, and sexual dysfunction. As a therapeutic alternative, effective herbal drugs may offer advantages in terms of safety and tolerability, possibly also improving patient compliance. The advent of the first antidepressants, Monoamine Oxidase Inhibitors (MAOIs and Tricyclic Antidepressants (TCAs, in the 1950s and 1960s represented a dramatic leap forward in the clinical management of depression. The subsequent development of the Selective Serotonin Reuptake Inhibitors (SSRIs and the Serotonin Norepinephrine Reuptake Inhibitor (SNRI venlafaxine in the past decade and a half has greatly enhanced the treatment of depression by offering patients medications that are as effective as the older agents but are generally more tolerable and safer in an overdose. The introduction of atypical antidepressants, such as bupropion, nefazadone, and mirtazapine, has added substantially to the available pharmacopoeia for depression. Nonetheless, rates of remission tend to be low and the risk of relapse and recurrence remains high. One of the concerns regarding the safety of antidepressant is its potential risk of cardiotoxicity and cardiovascular side effects. In this review, we will focus on the cardiovascular side effects of different types of antidepressants.

  11. Effect of Cesium Pressure on Thermionic Stability

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1969-08-01

    It is shown that under certain conditions of heat input, reservoir temperature, and load voltage or resistance a thermionic converter can equilibrate at two radically different operation points, corresponding to conditions of high and low cesium coverage. Moreover, abrupt transitions between these operating regimes, accompanied by a temperature rise of hundreds of degrees, can occur whenever the critical heat generation rate for a given reservoir temperature is exceeded. To provide an adequate safety margin against such an occurrence, thermionic systems must be operated at relatively high cesium pressures, even though this may cause some performance degradation. This paper consists of two parts. The first explains the above effect with reference to a single converter. The second part illustrates the effect of cesium reservoir temperatures on the dynamic behavior of an open-loop thermionic reactor following a small reactivity perturbation.

  12. The Effect of Zeolite on Aggregate Stability Indices

    Directory of Open Access Journals (Sweden)

    F. Sohrab

    2016-02-01

    Full Text Available Introduction: Soil structural stability affects the profitability and sustainability of agricultural systems. Particle size distribution (PSD and aggregate stability are the important characteristics of soil. Aggregate stability has a significant impact on the development of the root system, water and carbon cycle and soil resistance against soil erosion. Soil aggregate stability, defined as the ability of the aggregates to remain intact when subject to a given stress, is an important soil property that affects the movement and storage of water, aeration, erosion, biological activity and growth of crops. Dry soil aggregate stability (Mean Weight Diameter (MWD, Geometric Mean Diameter (GMD and Wet Aggregate Stability (WAS are important indices for evaluating soil aggregate stability.To improve soil physical properties, including modifying aggregate, using various additives (organic, inorganic and chemicals, zeolites are among what has been studied.According to traditional definition, zeolites are hydratealuminosilicates of alkaline and alkaline-earth minerals. Their structure is made up of a framework of[SiO4]−4 and [AlO4]−5 tetrahedron linked to each other's cornersby sharing oxygen atoms. The substitution of Si+4 by Al+3 intetrahedral sites results inmore negative charges and a high cation exchange capacity.Zeolites, as natural cation exchangers, are suitable substitutes to remove toxic cations. Among the natural zeolites,Clinoptilolite seems to be the most efficient ion exchanger and ion-selective material forremoving and stabilizing heavy metals.Due to theexisting insufficient technical information on the effects of using different levels of zeolite on physical properties of different types of soils in Iran, the aim of this research was to assess the effects of two different types of zeolite (Clinoptilolite natural zeolite, Z4, and Synthetic zeolite, A4 on aggregate stability indicesof soil. Materials and Methods: In this study at first

  13. Effects of Longwall subsidence on escarpment stability

    International Nuclear Information System (INIS)

    Shea-Albin, V.R.

    1992-01-01

    Increasing pressure from State and Federal agencies to mitigate mining-induced subsidence damage to overlying structures has presented a unique problem to the coal industry in the western United States. Because sandstone escarpments are an environmental issue, millions of tons of coal reserves that underlie these escarpments risk being classified as unminable by regulatory agencies. At this time, the effect of subsidence on escarpments has not been well documented or characterized. The Bureau of Mines is using numerical modeling techniques to analyze escarpment response to longwall mining. Two- and three-dimensional finite element models have been constructed for a study area near Price, Utah, where longwall panels were mined near an escarpment. This paper includes preliminary results showing that the pattern of subsidence surrounding the escarpment can be simulated through numerical modeling

  14. Nonlinear and Non-ideal Effects on FRC Stability

    International Nuclear Information System (INIS)

    Belova, E.V.; Davidson, R.C.; Ji, H.; Yamada, M.

    2002-01-01

    New computational results are presented which advance the understanding of the stability properties of the Field-Reversed Configuration (FRC). We present results of hybrid and two-fluid (Hall-MHD) simulations of prolate FRCs in strongly kinetic and small-gyroradius, MHD-like regimes. The n = 1 tilt instability mechanism and stabilizing factors are investigated in detail including nonlinear and resonant particle effects, particle losses along the open field lines, and Hall stabilization. It is shown that the Hall effect determines the mode rotation and change in the linear mode structure in the kinetic regime; however, the reduction in the growth rate is mostly due to the finite Larmor radius effects. Resonant particle effects are important in the large gyroradius regime regardless of the separatrix shape, and even in cases when a large fraction of the particle orbits are stochastic. Particle loss along the open field lines has a destabilizing effect on the tilt mode and contributes to the ion spin up in toroidal direction. The nonlinear evolution of unstable modes in both kinetic and small-gyroradius FRCs is shown to be considerably slower than that in MHD simulations. Our simulation results demonstrate that a combination of kinetic and nonlinear effects is a key for understanding the experimentally observed FRC stability properties

  15. Effect of acidification on carrot (Daucus carota) juice cloud stability.

    Science.gov (United States)

    Schultz, Alison K; Barrett, Diane M; Dungan, Stephanie R

    2014-11-26

    Effects of acidity on cloud stability in pasteurized carrot juice were examined over the pH range of 3.5-6.2. Cloud sedimentation, particle diameter, and ζ potential were measured at each pH condition to quantify juice cloud stability and clarification during 3 days of storage. Acidification below pH 4.9 resulted in a less negative ζ potential, an increased particle size, and an unstable cloud, leading to juice clarification. As the acidity increased, clarification occurred more rapidly and to a greater extent. Only a weak effect of ionic strength was observed when sodium salts were added to the juice, but the addition of calcium salts significantly reduced the cloud stability.

  16. Rapid determination of selenium in three kinds of biological standard reference materials using {sup 77m}Se nuclide

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jong Hwa; Kim, Sun Ha; Chung, Yong Sam; Kim, Young Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    A number of researches on essential trace elements have been performed in the field of human nutrition and health studies. From this viewpoint, selenium is well known as a strong antioxidant trace element for scavenging free radicals and a fast analytical technique of selenium in biological samples is indispensable for the satisfaction of a customer's request. This study was aimed at establishing an analytical method for the determination of the selenium in biological samples by a neutron activation analysis using the {sup 77m}Se short-lived nuclide. For this purpose, three NIST SRMs were chosen and the concentrations of the selenium were determined under prefixed analytical conditions such as the irradiation time, cooling time and measuring time. The measured values were compared with the certified values. In addition, the detection limits and measurement uncertainty were evaluated for the analytical results using {sup 77m}Se.

  17. String effective actions and cosmological stability of scalar potentials

    CERN Document Server

    García-Bellido, J; Garcia-Bellido, Juan; Quiros, Mariano

    1992-01-01

    The cosmology of the string effective action, including one loop string threshold corrections, is analyzed for static compactifications. The stability of the minima of a general supersymmetry breaking potential is studied in the presence of radiation. In particular, it is shown that the radiation bath makes the minima with negative cosmological constant unstable.

  18. Stability analysis of sandy slope considering anisotropy effect in ...

    Indian Academy of Sciences (India)

    This paper aims to investigate the effect of anisotropy of shear strength parameter on the stability of a sandy slope by performing the limit equilibrium analysis. Because of scarcity of mathematical equation for anisotropic friction angle of sand, at first, all results of principal stress rotation tests are processed by artificial neural ...

  19. The effect of stability treatmetn on the surface energetics of ...

    African Journals Online (AJOL)

    The effect of stability treatmetn on the surface energetics of inhalation grade lactose. IP Okoye. Abstract. No Abstract. Global Journal of Pure and Applied Physics Vol. 14 (1) 2008 pp.85-88. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  20. Effect of Guanidium Hydrochloride on the Stability of Horse Skeletal ...

    African Journals Online (AJOL)

    The stability of the three dimensional structure of horse skeletal muscle myoglobin was investigated using visible spectroscopy. Guanidium hydrochloride (GuHCl) of concentrations 0.4 – 0.8M have no observable effect on the three dimensional structure as indicated by monitoring the absorbance at 420nm. However, higher ...

  1. Effects of some storage conditions on the stability of hydrocortisone ...

    African Journals Online (AJOL)

    In this study, the effects of some environmental storage conditionslight, temperature and humidity on the stability of the steroidal drug, hydrocortisone sodium succinate injection were investigated. The drug samples were stored at varying conditions of light, temperature (0°C, 28°C and 60°C) and humidity, after which each ...

  2. Stabilization effect of Weibel modes due to inverse bremsstrahlung ...

    Indian Academy of Sciences (India)

    2016-11-04

    Nov 4, 2016 ... Abstract. In this work, the Weibel instability due to inverse bremsstrahlung absorption in laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by Weibel instability with the laser wave field is explicitly showed. The main result obtained in ...

  3. Effects of Preservative Techniques on the Storage Stability of ...

    African Journals Online (AJOL)

    The effect of different preservative techniques on the storage stability of sorghum stem sheath beverage was studied. A portion of the beverage samples were pasteurized at 75oC for 15 mins, another pasteurized and refrigerated and the other pasteurized and preserved with 0.1% sodium benzoate and they were studied at ...

  4. Effect of some stabilizing agents on globule characteristics and ...

    African Journals Online (AJOL)

    This study investigated the effects of some stabilizing agents (cassava, maize and bentonite mucilages) on globule characteristics and rheological properties of oil in water emulsions. Emulsions were prepared by mixing varying proportions of the mucilages with Arachis oil in the ratio of 60:40 (oil: water) with the aid of a ...

  5. Roughness effects on the thermal stability of thin films

    NARCIS (Netherlands)

    Palasantzas, George

    1997-01-01

    In this work, we investigate interface roughness effects on the energetic terms that play a key role on the thermal stability of thin silicide films. The roughness is modeled as a self-affine structure with power spectrum ~σ^2ξ^2(1+aq^2ξ^2)^-1-H convoluted with a domain size distribution ∝

  6. Operational Stability of Organic Field‐Effect Transistors

    NARCIS (Netherlands)

    Bobbert, P.A.; Sharma, A.; Matthijssen, S.J.G.; Kemerink, M.; de Leeuw, D.M.

    2012-01-01

    Organic field-effect transistors (OFETs) are considered in technological applications for which low cost or mechanical flexibility are crucial factors. The environmental stability of the organic semiconductors used in OFETs has improved to a level that is now sufficient for commercialization.

  7. Copolymer adsorption and the effect on colloidal stability

    NARCIS (Netherlands)

    Bijsterbosch, H.D.

    1998-01-01

    The main aim of the work described in this thesis is to study the effect of different types of copolymers on the stability of aqueous oxide dispersions. Such dispersions are a major component in water-borne paints. In order to obtain a better insight in steric stabilisation we first investigated the

  8. Stabilization effect of Weibel modes due to inverse bremsstrahlung ...

    Indian Academy of Sciences (India)

    In this work, the Weibel instability due to inverse bremsstrahlung absorption in laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by Weibel instability with the laser wave field is explicitly showed. The main result obtained in this work is that the inclusion ...

  9. Effect of different microencapsulation materials on stability of ...

    African Journals Online (AJOL)

    The aim of this work was to investigate the effect of different microencapsulation materials on the stability of probiotic bacterium (Lactobacillus plantarum DSM 20174). Microencapsulation methods with alginates were carried out using sodium chloride, canola oil, olive oil, and chitosan. The recorded data showed that the ...

  10. Effect of fluoride ion on the stability of DNA hairpin

    Science.gov (United States)

    Liu, Chao; Zhai, Weili; Gong, Hongling; Liu, Yanhui; Chen, Hu

    2017-06-01

    Fluoride prevents tooth decay as an additive in oral hygiene products, while high dose intake of fluoride from contaminated drinking water leads to fluorosis. Here we studied the effect of fluoride ion on the stability of DNA double helix using magnetic tweezers. The equilibrium critical force decreases with increasing concentration of fluoride in the range from 1 mM to 100 mM. Our results give the first quantitative measurement of DNA stability in the presence of fluoride ion, which might disturb DNA-related biological processes to cause fluorosis.

  11. Finite-Larmor-radius effects on z-pinch stability

    Science.gov (United States)

    Scheffel, Jan; Faghihi, Mostafa

    1989-06-01

    The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. We use the incompressible FLR MHD model; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2r dp/dr + m2B2/μ0 ≥ 0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the FLR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but not absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the crosssection for wavelengths λ/a ≤ 1, where a denotes the pinch radius. As a general z-pinch result a critical line-density limit Nmax = 5 × 1018 m-1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 1020 m-1.

  12. Wellbore stability in shales considering chemo-poroelastic effects

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Ewerton M.P.; Pastor, Jorge A.S.C.; Fontoura, Sergio A.B.; Rabe, Claudio [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil. Grupo de Tecnologia e Engenharia de Petroleo

    2004-07-01

    Under compaction and low geothermal gradients are deep water characteristics. Both under compaction and low geothermal gradients generate considerable thickness of smectite-rich shales. These rocks are the major source of wellbore stability problems, because they are susceptible to adverse physico-chemical reactions when in contact with inadequate drilling fluids. Due shales are low permeability rocks diffusion processes dominate the changes of pore pressure around wellbore. Diffusion of fluids, ions and temperature occurs in shales during drilling and demand a fully coupled modelling taking account these factors. Despite temperature importance, in this paper wellbore stability in shales is analyzed through a model that considers only the coupling between poroelastic and physico-chemical effects. The coupled equations are solved analytically and have been implemented in a computational simulator with user-friendly interface. Time-dependent simulations of wellbore stability in shales are presented for a typical deep water scenario. The results show that physico-chemical effects change pore pressure around wellbore and have high impact on the wellbore stability. (author)

  13. Evolution of the central safety factor during stabilized sawtooth instabilities at KSTAR

    Science.gov (United States)

    Messmer, M. C. C.; Ko, J.; Chung, J.; Woo, M. H.; Lee, K.-D.; Jaspers, R. J. E.

    2018-01-01

    A motional Stark effect (MSE) diagnostic has recently been installed in the KSTAR tokamak. A difficulty faced at KSTAR and common to other MSE diagnostics is calibration of the system for absolute measurements. In this report we present our novel calibration routine and discuss first results, evaluating the evolution of the the central safety factor during sawtooth instabilities. The calibration scheme ensures that the bandpass filters typically used in MSE systems are aligned correctly and identifies and removes systematic offsets present in the measurement. This is verified by comparing the reconstructed safety factor profile against various discharges where the locations of rational q surfaces have been obtained from MHD markers. The calibration is applied to analyse the evolution of q 0 in a shot where the sawteeth are stabilized by neutral beam injection. Within the analysed sawtooth periods q 0 drops below unity during the quiescent phase and relaxes close to or slightly above unity at the sawtooth crash. This finding is in line with the classical Kadomtsev model of full magnetic reconnection and earlier findings at JET.

  14. Substituent Effects on the Stability and Antioxidant Activity of Spirodiazaselenuranes

    Directory of Open Access Journals (Sweden)

    Devappa S. Lamani

    2015-07-01

    Full Text Available Spirodiazaselenuranes are structurally interesting compounds and the stability of these compounds depends highly on the nature of the substituents attached to the nitrogen atoms. Aromatic substituents are known to play important roles in stabilizing the Se-N bonds in spiro compounds. In this study, several spirodiazaselenuranes are synthesized by introducing benzylic and aliphatic substituents to understand their effect on the stability of the Se-N bonds and the antioxidant activity. Replacement of phenyl substituent by benzyl/alkyl groups significantly reduces the stability of the spirodiazaselenuranes and slows down the oxidative cyclization process. The selenium centre in the spiro compounds undergoes further oxidation to produce the corresponding selenurane oxides, which are stable at room temperature. Comparison of the glutathione peroxidase (GPx mimetic activity of the compounds showed that the diaryl selenides having heterocyclic rings are significantly more active due to the facile oxidation of the selenium centre. However, the activity is reduced significantly for compounds having aliphatic substituents. In addition to GPx activity, the compounds also inhibit peroxynitrite-mediated nitration and oxidation reaction of protein and small molecules, respectively. The experimental observations suggest that the antioxidant activity is increased considerably upon substitution of the aromatic group with the benzylic/aliphatic substituents on the nitrogen atoms.

  15. The Condensation effect on the two-phase flow stability

    International Nuclear Information System (INIS)

    Abdou Mohamed, Hesham Nagah

    2005-01-01

    A one-dimensional analytical model has been developed to be used for the linear analysis of density-wave oscillations in a parallel heated channel and a natural circulation loop.The heater and the riser sections are divided into a single-phase and a two-phase region.The two-phase region is represented by the drift-flux model. The model accounts for aphasic slip and subcooled boiling.The localized friction at the heater and the riser exit is treated considering the two-phase mixture.Also the effects of the condensation in the riser and the change in the system pressure have been studied.The exact equation for the heated channel and the total loop pressure drop is perturbed around the steady state.he stability characteristics of the heated channel and the loop are investigated using the Root finding method criterion.The results are summarized on instability maps in the plane of subcooled boiling number vs. phase change number (i.e., inlet subcooling vs. heater heat flux).The predictions of the model are compared with experimental results published in open literature. The results show that, the treatment effect of localized friction in two-phase mixtures stabilizes the system and improves the agreement of the calculations with the experimental results.For a parallel heated channel, the results indicate a more stable system with high inlet restriction, low outlet restriction, and high inlet velocity. And for a natural circulation loop, an increase in the inlet restriction broadened the range of the continuous circulation mode and stabilized the system, a decrease in the exit restriction or the liquid charging level shifted to the right the range of the continuous circulation mode and stabilized the system and an increase in the riser condensation shifted to the right the range of the continuous circulation mode and stabilized the system.The results show that the model agrees well with the available experimental data. In particular, the results show the significance of

  16. Local effect of equilibrium current on tearing mode stability

    International Nuclear Information System (INIS)

    Cozzani, F.

    1985-12-01

    The local effect of the equilibrium current on the linear stability of low poloidal number tearing modes in tokamaks is investigated analytically. The plasma response inside the tearing layer is derived from fluid theory and the local equilibrium current is shown to couple to the mode dynamics through its gradient, which is proportional to the local electron temperature gradient under the approximations used in the analysis. The relevant eigenmode equations, expressing Ampere's law and the plasma quasineutrality condition, respectively, are suitably combined in a single integral equation, from which a variational principle is formulated to derive the mode dispersion relations for several cases of interest. The local equilibrium current is treated as a small perturbation of the known results for the m greater than or equal to 2 and the m = 1 tearing modes in the collisional regime, and the m greater than or equal to 2 tearing mode in the semicollisional regime; its effect is found to enhance stabilization for the m greater than or equal to 2 drift-tearing mode in the collisional regime, whereas the m = 1 growth rate is very slightly increased and the stabilizing effect of the parallel thermal conduction on the m greater than or equal to 2 mode in the semicollisional regime is slightly reduced

  17. Stabilization effect of Weibel modes in relativistic laser fusion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Belghit, Slimen, E-mail: Belghit.slimen@gmail.com; Sid, Abdelaziz, E-mail: Sid-abdelaziz@hotmail.com [Laboratoire de Physique des rayonnements et de leurs interactions avec la matière (PRIMALAB), département de Physique, faculté des Sciences de la Matière, Université de Batna 1, 05000DZ, Batna (Algeria)

    2016-06-15

    In this work, the Weibel instability (WI) due to inverse bremsstrahlung (IB) absorption in a laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by WI with the laser wave field is explicitly shown. In this study, the relativistic effects are taken into account. Here, the basic equation is the relativistic Fokker-Planck (F-P) equation. The main obtained result is that the coupling of self-generated magnetic field with the laser wave causes a stabilizing effect of excited Weibel modes. We found a decrease in the spectral range of Weibel unstable modes. This decreasing is accompanied by a reduction of two orders in the growth rate of instable Weibel modes or even stabilization of these modes. It has been shown that the previous analysis of the Weibel instability due to IB has overestimated the values of the generated magnetic fields. Therefore, the generation of magnetic fields by the WI due to IB should not affect the experiences of an inertial confinement fusion.

  18. Stabilizing Effects of Bacterial Biofilms: EPS Penetration and Redistribution of Bed Stability Down the Sediment Profile

    Science.gov (United States)

    Chen, X. D.; Zhang, C. K.; Zhou, Z.; Gong, Z.; Zhou, J. J.; Tao, J. F.; Paterson, D. M.; Feng, Q.

    2017-12-01

    Biofilms, consisting of microorganisms and their secreted extracellular polymeric substances (EPSs), serve as "ecosystem engineers" stabilizing sedimentary environments. Natural sediment bed provides an excellent substratum for biofilm growth. The porous structure and rich nutrients allow the EPS matrix to spread deeper into the bed. A series of laboratory-controlled experiments were conducted to investigate sediment colonization of Bacillus subtilis and the penetration of EPS into the sediment bed with incubation time. In addition to EPS accumulation on the bed surface, EPS also penetrated downward. However, EPS distribution developed strong vertical heterogeneity with a much higher content in the surface layer than in the bottom layer. Scanning electron microscope images of vertical layers also displayed different micromorphological properties of sediment-EPS matrix. In addition, colloidal and bound EPSs exhibited distinctive distribution patterns. After the full incubation, the biosedimentary beds were eroded to test the variation of bed stability induced by biological effects. This research provides an important reference for the prediction of sediment transport and hence deepens the understanding of the biologically mediated sediment system and broadens the scope of the burgeoning research field of "biomorphodynamics."

  19. Thermodynamic stabilization of precipitates through interface segregation: Chemical effects

    Science.gov (United States)

    Kadambi, Sourabh B.; Patala, Srikanth

    2017-09-01

    Precipitation hardening, which relies on a high density of intermetallic precipitates, is a commonly utilized technique for strengthening structural alloys. At high temperatures, however, the precipitates often coarsen to reduce the excess energy of the interface, resulting in a significant reduction in the strengthening achieved. In certain ternary alloys, secondary solute segregation to the interface has been observed to result in the formation of a high density of nanosized precipitates that provide enhanced strength and are resistant to coarsening. To understand the chemical effects involved, and to identify such segregating systems, we develop a thermodynamic model using the framework of the regular nanocrystalline solution model. For various global compositions, temperatures, and thermodynamic parameters, we evaluate equilibrium configurations of a Mg-Sn-Zn alloy by minimizing the Gibbs free energy function with respect to region-specific (bulk solid solution, interface, and precipitate) concentrations and sizes. The results show that Mg2Sn precipitates can be stabilized to nanoscale sizes through Zn segregation to the Mg /Mg2Sn interface, and the precipitates can be stabilized against coarsening at high temperatures through strong Mg-Zn interface interaction. Together with the inclusion of elastic strain energy effects, kinetic contributions, and the input of computationally informed interface parameters in the future, the model is expected to provide a more realistic prediction of segregation and precipitate stabilization in ternary alloys of structural importance.

  20. Radion stabilization by stringy effects in general relativity

    International Nuclear Information System (INIS)

    Patil, Subodh P.; Brandenberger, Robert

    2005-01-01

    We consider the effects of a gas of closed strings (treated quantum mechanically) on a background where one dimension is compactified on a circle. After we address the effects of a time-dependent background on aspects of the string spectrum that concern us, we derive the energy-momentum tensor for a string gas and investigate the resulting space-time dynamics. We show that a variety of trajectories are possible for the radius of the compactified dimension, depending on the nature of the string gas, including a demonstration within the context of general relativity (i.e. without a dilaton) of a solution where the radius of the extra dimension oscillates about the self-dual radius, without invoking matter that violates the various energy conditions. In particular, we find that in the case where the string gas is in thermal equilibrium, the radius of the compactified dimension dynamically stabilizes at the self-dual radius, after which a period of usual Friedmann-Robertson-Walker cosmology of the three uncompactified dimensions can set in. We show that our radion stabilization mechanism requires a stringy realization of inflation as scalar field driven inflation invalidates our mechanism. We also show that our stabilization mechanism is consistent with observational bounds

  1. Analysis of membrane proteome by data-dependent LC-MS/MS combined with data-independent LC-MSE technique

    Directory of Open Access Journals (Sweden)

    Joseph Kwon

    2010-03-01

    Full Text Available Proteomics work resembles the search for a needle in a haystack. The identification of protein biomarker requires the removal of the false protein data from the whole protein mixture. For high quality proteomic data, even a strict filtration step using the false discovery rate (FDR is insufficient for obtaining perfect protein information from the biological samples. In this study, the cyanobacterial whole membrane fraction was applied to the data-dependent analysis (DDA mode of LC-MS/MS, which was used along with the data-independent LC-MSE technique in order to evaluate the membrane proteomic data. Furthermore, the identified MSE-information (MSE-i data based on the peptide mass and the retention time were validated by the other database search, i.e., the probability-based MASCOT and de novo search engine PEAKS. In this present study, 208 cyanobacterial proteins with FDR of 5% were identified using the data-independent nano-UPLC/MSE acquisition with the Protein Lynx Global Server (PLGS, and 56 of these proteins were the predicted membrane proteins. When a total of 208 MSE-i proteomic data were applied to the DDA mode of LC-MS/MS, the number of identified membrane proteins was 26 and 33 from MASCOT and PEAKS with a FDR of 5%, respectively. The number of totally overlapped membrane proteins was 25. Therefore, the data-independent LC-MSE identified more proteins with a high confidence.

  2. Noise stabilization effects in models of interdisciplinary physics

    Science.gov (United States)

    Spagnolo, B.; Augello, G.; Caldara, P.; Fiasconaro, A.; La Cognata, A.; Pizzolato, N.; Valenti, D.; Dubkov, A. A.; Pankratov, A. L.

    2009-06-01

    Metastability is a generic feature of many nonlinear systems, and the problem of the lifetime of metastable states involves fundamental aspects of nonequilibrium statistical mechanics. The investigation of noise-induced phenomena in far from equilibrium systems is one of the approaches used to understand the behaviour of physical and biological complex systems. The enhancement of the lifetime of metastable states through the noise enhanced stability effect and the role played by the resonant activation phenomenon will be discussed in models of interdisciplinary physics: (i) polymer translocation dynamics; (ii) transient regime of FitzHugh-Nagumo model; (iii) market stability in a nonlinear Heston model; (iv) dynamics of Josephson junctions; (v) metastability in a quantum bitable system.

  3. Effect of nose bluntness on boundary layer stability and transition

    Science.gov (United States)

    Malik, M. R.; Spall, R. E.; Chang, C.-L.

    1990-01-01

    The effect of nose bluntness on boundary layer instability is studied theoretically for a Mach 8 flow past a 7 degree semivertex cone. The basic flow is computed by solving the parabolized Navier-Stokes equations. Linear stability analysis of the basic flow reveals that, with small amount of bluntness, the critical Reynolds number for the onset of instability increases by an order of magnitude compared to the sharp cone value. The computed second mode frequencies are also in reasonable agreement with the experimental results. The results are used to explain the effect of unit Reynolds number on transition present in the quiet aeroballistic range data.

  4. Liquid Self-Balancing Device Effects on Flexible Rotor Stability

    Directory of Open Access Journals (Sweden)

    Leonardo Urbiola-Soto

    2013-01-01

    Full Text Available Nearly a century ago, the liquid self-balancing device was first introduced by M. LeBlanc for passive balancing of turbine rotors. Although of common use in many types or rotating machines nowadays, little information is available on the unbalance response and stability characteristics of this device. Experimental fluid flow visualization evidences that radial and traverse circulatory waves arise due to the interaction of the fluid backward rotation and the baffle boards within the self-balancer annular cavity. The otherwise destabilizing force induced by trapped fluids in hollow rotors, becomes a stabilizing mechanism when the cavity is equipped with adequate baffle boards. Further experiments using Particle Image Velocimetry (PIV enable to assess the active fluid mass fraction to be one-third of the total fluid mass. An analytical model is introduced to study the effects of the active fluid mass fraction on a flexible rotor supported by flexible supports excited by bwo different destabilizing mechanisms; rotor internal friction damping and aerodynamic cross-coupling. It is found that the fluid radial and traverse forces contribute to the balancing action and to improve the rotor stability, respectively.

  5. Design and installation of the MSE septum system in the new LSS4 extraction channel of the SPS

    CERN Document Server

    Balhan, B; Guinand, R; Luiz, F; Rizzo, A; Weterings, W; CERN. Geneva. AB Department

    2003-01-01

    For the extraction of the beam from the Super Proton Synchrotron (SPS) to ring 2 of the Large Hadron Collider (LHC) and the CERN Neutrino to Gran Sasso (CNGS) facility, a new fast-extraction system has been installed in the long straight section LSS4 of the SPS. Besides extraction bumpers, enlarged aperture quadrupoles and extraction kicker magnets (MKE), six conventional DC septum magnets (MSE) are used. These magnets are mounted on a single mobile retractable support girder, which is motorised in order to optimise the local SPS aperture during setting up. The MSE septa are connected by a so-called plug-in system to a rigid water-cooled bus bar, which itself is powered by water-cooled cables. In order to avoid destruction of the septum magnet coils by direct impact of the extracted beam, a dilution element (TPSG) has been placed immediately upstream of the first septum coil. The whole system is kept at the required vacuum pressure by ion pumps attached to separate modules (MP). In this note we present the de...

  6. Stabilization of the Electroweak Vacuum by a Scalar Threshold Effect

    CERN Document Server

    Elias-Miro, Joan; Giudice, Gian F.; Lee, Hyun Min; Strumia, Alessandro

    2012-01-01

    We show how a heavy scalar singlet with a large vacuum expectation value can evade the potential instability of the Standard Model electroweak vacuum. The quartic interaction between the heavy scalar singlet and the Higgs doublet leads to a positive tree-level threshold correction for the Higgs quartic coupling, which is very effective in stabilizing the potential. We provide examples, such as the see-saw, invisible axion and unitarized Higgs inflation, where the proposed mechanism is automatically implemented in well-defined ranges of Higgs masses.

  7. The effect of simulated acid rain on the stabilization of cadmium in contaminated agricultural soils treated with stabilizing agents.

    Science.gov (United States)

    Zhu, Hao; Wu, Chunfa; Wang, Jun; Zhang, Xumei

    2018-04-16

    Stabilization technology is one of widely used remediation technologies for cadmium (Cd)-contaminated agricultural soils, but stabilized Cd in soil may be activated again when external conditions such as acid rain occurred. Therefore, it is necessary to study the effect of acid rain on the performance of different stabilizing agents on Cd-polluted agriculture soils. In this study, Cd-contaminated soils were treated with mono-calcium phosphate (MCP), mono-ammonium phosphate (MAP), and artificial zeolite (AZ) respectively and incubated 3 months. These treatments were followed by two types of simulated acid rain (sulfuric acid rain and mixed acid rain) with three levels of acidity (pH = 3.0, 4.0, and 5.6). The chemical forms of Cd in the soils were determined by Tessier's sequential extraction procedure, and the leaching toxicities of Cd in the soils were assessed by toxicity characteristic leaching procedure (TCLP). The results show that the three stabilizing agents could decrease the mobility of Cd in soil to some degree with or without simulated acid rain (SAR) treatment. The stabilization performances followed the order of AZ Acid rain soaking promoted the activation of Cd in stabilized soil, and both anion composition and pH of acid rain were two important factors that influenced the stabilization effect of Cd.

  8. The application of methylation specific electrophoresis (MSE to DNA methylation analysis of the 5' CpG island of mucin in cancer cells

    Directory of Open Access Journals (Sweden)

    Yokoyama Seiya

    2012-02-01

    Full Text Available Abstract Background Methylation of CpG sites in genomic DNA plays an important role in gene regulation and especially in gene silencing. We have reported mechanisms of epigenetic regulation for expression of mucins, which are markers of malignancy potential and early detection of human neoplasms. Epigenetic changes in promoter regions appear to be the first step in expression of mucins. Thus, detection of promoter methylation status is important for early diagnosis of cancer, monitoring of tumor behavior, and evaluating the response of tumors to targeted therapy. However, conventional analytical methods for DNA methylation require a large amount of DNA and have low sensitivity. Methods Here, we report a modified version of the bisulfite-DGGE (denaturing gradient gel electrophoresis using a nested PCR approach. We designated this method as methylation specific electrophoresis (MSE. The MSE method is comprised of the following steps: (a bisulfite treatment of genomic DNA, (b amplification of the target DNA by a nested PCR approach and (c applying to DGGE. To examine whether the MSE method is able to analyze DNA methylation of mucin genes in various samples, we apply it to DNA obtained from state cell lines, ethanol-fixed colonic crypts and human pancreatic juices. Result The MSE method greatly decreases the amount of input DNA. The lower detection limit for distinguishing different methylation status is Conclusions The MSE method can provide a qualitative information of methylated sequence profile. The MSE method allows sensitive and specific analysis of the DNA methylation pattern of almost any block of multiple CpG sites. The MSE method can be applied to analysis of DNA methylation status in many different clinical samples, and this may facilitate identification of new risk markers.

  9. Effects of Sound on Postural Stability during Quiet Standing

    Directory of Open Access Journals (Sweden)

    Park Sung

    2011-12-01

    Full Text Available Abstract Loss of postural stability can increase the likelihood of slips and falls in workplaces. The present study intended to extend understanding of the effects of frequency and pressure level of sound on postural stability during standing. Eleven male subjects participated. Standing on a force platform, the subjects' center of pressures were measured under different combinations of pressure level and frequency of the sound. Variables such as the position variability of COP and the length of postural sway path in anterior-posterior (AP and medio-lateral (ML direction were evaluated. Subjective ratings of perceived disturbance at each experimental condition were also obtained using a 7-point rating scale. Results showed that the length of sway path and the position variability of COP increased as the frequency of sound increased in posterior-anterior axis. The effect of sound pressure level, however, was not significant on both the postural sway length and the position variability of COP. These results suggested substantial disturbance of standing balance system among subjects exposed to high frequency noise. The results implied that physical workers should be alerted that their abilities of postural balance could be degraded significantly as disturbance caused by a sound existed.

  10. Pressure effects on the thermal stability of silicon carbide fibers

    Science.gov (United States)

    Jaskowiak, Martha H.; Dicarlo, James A.

    1989-01-01

    Commercially available polymer derived SiC fibers were treated at temperatures from 1000 to 2200 C in vacuum and argon gas pressure of 1 and 1360 atm. Effects of gas pressure on the thermal stability of the fibers were determined through property comparison between the pressure treated fibers and vacuum treated fibers. Investigation of the thermal stability included studies of the fiber microstructure, weight loss, grain growth, and tensile strength. The 1360 atm argon gas treatment was found to shift the onset of fiber weight loss from 1200 to above 1500 C. Grain growth and tensile strength degradation were correlated with weight loss and were thus also inhibited by high pressure treatments. Additional heat treatment in 1 atm argon of the fibers initially treated at 1360 atm argon caused further weight loss and tensile strength degradation, thus indicating that high pressure inert gas conditions would be effective only in delaying fiber strength degradation. However, if the high gas pressure could be maintained throughout composite fabrication, then the composites could be processed at higher temperatures.

  11. Effect of heating on the stability of quinolones in milk.

    Science.gov (United States)

    Roca, M; Castillo, M; Marti, P; Althaus, R L; Molina, M P

    2010-05-12

    Nowadays, the possible public health risk associated with the presence of quinolone residues and other antibiotics in milk is well-known, but there is a lack of information about the effect milk processing temperatures have on the presence of antimicrobial residues. The aim of this work was to determine the effect of different temperatures and heating times on the concentration of quinolones in milk by employing liquid chromatographic equipment analysis with fluorescence detection. In order to determine the thermo-stability of these compounds, the first-order kinetic model was applied, and the activation energies, half-lives, and percentages of degradation of each compound were calculated. Results showed that quinolones are very resistant to different heat treatments with maximum losses of concentration of 12.71% for ciprofloxacin and 12.01% for norfloxacin at 120 degrees C and 20 min. The high stability of quinolones represents a significant risk to human health because the residues of these antibiotics can remain in milk after heat treatment and, therefore, can reach the dairy industry and consumers.

  12. Effects of sound on postural stability during quiet standing.

    Science.gov (United States)

    Park, Sung Ha; Lee, Kichol; Lockhart, Thurmon; Kim, Sukwon

    2011-12-15

    Loss of postural stability can increase the likelihood of slips and falls in workplaces. The present study intended to extend understanding of the effects of frequency and pressure level of sound on postural stability during standing. Eleven male subjects participated. Standing on a force platform, the subjects' center of pressures were measured under different combinations of pressure level and frequency of the sound. Variables such as the position variability of COP and the length of postural sway path in anterior-posterior (AP) and medio-lateral (ML) direction were evaluated. Subjective ratings of perceived disturbance at each experimental condition were also obtained using a 7-point rating scale. Results showed that the length of sway path and the position variability of COP increased as the frequency of sound increased in posterior-anterior axis. The effect of sound pressure level, however, was not significant on both the postural sway length and the position variability of COP. These results suggested substantial disturbance of standing balance system among subjects exposed to high frequency noise. The results implied that physical workers should be alerted that their abilities of postural balance could be degraded significantly as disturbance caused by a sound existed.

  13. A piloted simulator investigation of static stability and stability/control augmentation effects on helicopter handling qualities for instrument approach

    Science.gov (United States)

    Lebacqz, J. V.; Forrest, R. D.

    1980-01-01

    A ground simulator experiment was conducted on the Flight Simulator for Advanced Aircraft at Ames Research Center to investigate the influence of several static stability and stability/control augmentation design parameters on helicopter flying qualities during terminal area operations in instrument conditions. Effects of light turbulence were included. Two levels of static stability in each rotational axis (pitch, roll, yaw) were examined for a hingeless rotor configuration. The variations in pitch and roll were: (1) stable and (2) neutral static stability; in yaw there were two stable levels. Four types of stability/control augmentation were also examined for the lower level of static stability in each axis. This latter investigation covered three helicopter rotor types: hingeless, articulated, and teetering. Four pilots performed a total of 105 evaluations of these parameters for a representative VOR instrument approach task. Pilot rating results indicate the acceptability of neutral static stability longitudinally and laterally and the need for pitch-roll attitude augmentation to achieve a satisfactory system.

  14. Immobilization of uranium by biomaterial stabilized FeS nanoparticles: Effects of stabilizer and enrichment mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Dadong [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Ren, Xuemei, E-mail: renxm_nana@163.com [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Wen, Jun; Hu, Sheng; Xiong, Jie; Jiang, Tao [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, Xiaolin, E-mail: xlwang@caep.ac.cn [China Academy of Engineering Physics, Mianyang 621900 (China); Wang, Xiangke, E-mail: xkwang@ncepu.edu.cn [School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China)

    2016-01-25

    Highlights: • FeS can be stabilized by sodium carboxymethyl cellulose and gelatin. • Gelatin–FeS show best performance in U(VI) removal. • Adsorption–reduction immobilization of U(VI) is the major mechanism. - Abstract: Iron sulfide (FeS) nanoparticles have been recognized as effective scavengers for multi-valent metal ions. However, the aggregation of FeS nanoparticles in aqueous solution greatly restricts their application in real work. Herein, different biomaterial-FeS nanoparticles were developed for the in-situ immobilization of uranium(VI) in radioactive waste management. TEM images suggested that sodium carboxymethyl cellulose (CMC) and gelatin can effectively suppress the aggregation of FeS nanoparticles in aqueous solutions. The resulting CMC–FeS and gelatin–FeS were stable in aqueous solutions and showed high adsorption capacity for U(VI). Specially, gelatin–FeS showed the best performance in U(VI) adsorption–reduction immobilization under experimental conditions. The maximum enrichment capacity of U(VI) on CMC–FeS and gelatin–FeS at pH 5.0 and 20 °C achieved to ∼430 and ∼556 mg/g, respectively. Additionally, gelatin–FeS and CMC–FeS nanoparticles presented excellent tolerance to environmental salinity. The immobilized U(VI) on the surfaces of CMC–FeS and gelatin–FeS remained stable more than one year. These findings highlight the possibility of using ggelatin–FeS for efficient immobilization of U(VI) from radioactive wastewater.

  15. Effect of Rice Husk Ash on Soil Stabilization

    OpenAIRE

    Muhammad Qasim; Aroj Bashir; Mubashar Tanvir; Malik Muhammad Anees

    2015-01-01

    The soil frequently is fragile and has low stability in heavy loading. The objective of this study is to review the stabilization of soil using sustainable methods. Some strengthening approaches are available for stabilization of expansive soils. These methods consist of stabilization with soil replacement, chemical additives, moisture control, rewetting, surcharge loading, compaction control and thermal methods. The disadvantages may be associated with all these methods due to ineffectivenes...

  16. Global stability of discrete-time recurrent neural networks with impulse effects

    International Nuclear Information System (INIS)

    Zhou, L; Li, C; Wan, J

    2008-01-01

    This paper formulates and studies a class of discrete-time recurrent neural networks with impulse effects. A stability criterion, which characterizes the effects of impulse and stability property of the corresponding impulse-free networks on the stability of the impulsive networks in an aggregate form, is established. Two simplified and numerically tractable criteria are also provided

  17. Erythrocyte membrane stabilization effect and antioxidant activity of methyl methacrylate

    International Nuclear Information System (INIS)

    Popov, B.

    2004-01-01

    Methyl methacrylate (MMK) is a synthetic product with mild impact on human health that is not well studied on cellular basis. Here, human erythrocytes were used to investigate the effects MMK exerts on acid and heat-induced hemolysis. Biphasic effect of MMK was observed for acid-induced hemolysis; i.e., protection at low (0 - 0.05% v/v) and stimulation at higher (0.1- 0.4% v/v) concentrations. The maximal protective effect was produced at 0.03% (v/v). At this concentration MMK increased the temperatures of heat denaturation of erythrocyte membrane proteins, spectrin and integral proteins, by about 2 0 C and inhibited the heat-induced hemolysis by 20 %. This membrane stabilization effect of MMK is similar to that produced by some anti-inflammatory and antirheumatic drugs. The increased acid resistance possibly indicated anti-oxidant properties of MMK. The nonenzymatic antioxidant activity test evidenced that MMK has no superoxide dismutase-like activity but demonstrates strong catalase-like activity (about 900 kU/mmol at 0.05-0.1 mmol/l concentration). The results indicate that at low concentration MMK exerts benign effect on cellular membrane that could find therapeutic usage. (author)

  18. Biochar carbon stability and effect on greenhouse gas emissions

    DEFF Research Database (Denmark)

    Bruun, Esben Wilson; Cross, Andrew; Hammond, Jim

    2016-01-01

    As demonstrated by several scientific studies there is no doubt that biochar in general is very recalcitrant compared to other organic matter additions and soil organic matter fractions and also that it is possible to sequester carbon at a climate change relevant time scale (~100 years or more......) by soil application of biochar. However, the carbon stability of biochar in soil is strongly correlated with the degree of thermal alteration of the original feedstock (the lower the temperature, the larger the labile fraction) and in depth understanding of the technology used and its effect...... on the biochar quality is necessary in order to produce the most beneficial biochars for soil application. Beside carbon sequestration in soil biochar may improve the GHG balance by reducing N2O and CH4 soil emissions, although contrasting results are found in the literature. The mechanisms behind...

  19. Effect of kinesio-taping on ankle joint stability

    Directory of Open Access Journals (Sweden)

    Mervat A. Mohamed

    2016-05-01

    Full Text Available Ankle Instability is characterized by recurrent giving way and often develops after repeated lateral ankle sprains. Kinesiotape is more elastic than traditional athletic tape and is becoming increasingly popular. It is reported to decrease pain, improve muscle function, circulation and proprioception, however, research examining the effects of Kinesiotape in ankle instability is limited. The objective of this study was to determine if applying Kinesiotape to unstable ankle may improve performance in the Star Excursion Balance Test (SEBT, which has been shown to be a sensitive and reliable measure for quantifying dynamic balance. Thirty subjects with first degree ankle sprain were participated in this study. SEBT was used to test the subject dynamic balance under three conditions; without taping, with white athletic tape and with kinesiotape. One way repeated measure ANOVA using Greenhouse-Geisser corrections were conducted to evaluate differences in SEBT for the three conditions. Pairwise comparison of the outcome measures in the three occasions (without taping, with athletic taping, and with kinesio taping revealed statistically significant differences of all outcomes between occasion 1 (without taping and occasion 2 (with athletic taping favoring the athletic taping (p < 0.05. Also, a statistically significant difference between occasion 1 (without taping and occasion 3 (with kinesio taping were found (p < 0.05 favoring kinesio taping. Moreover, pairwise comparison of the ankle stability outcomes using athletic taping versus kinesio taping indicated a statistically significant difference (p < 0.05 in favor of kinesio taping measures. Conclusion: kinesiotape has superior effect than athletic tape in patients with first degree ankle sprain and can be used safely for improving ankle joint stability.

  20. Distribution of chloride, pH, resistivity, and sulfate levels in backfill for mechanically-stabilized earth walls and implications for corrosion testing : [summary].

    Science.gov (United States)

    2015-04-01

    Road construction projects often require mechanically stabilized earth (MSE), earthwork : construction in which soil is retained by walls and reinforced with wire mesh, metal strips, : and structural geosynthetics (geotextile or geogrid). The fill so...

  1. Distribution of chloride, pH, resistivity, and sulfate levels in backfill for mechanically-stabilized earth walls and implications for corrosion testing.

    Science.gov (United States)

    2015-05-01

    The ultimate goals of this research were to improve quality, speed completion, and reduce risk in mechanically-stabilized : earth (MSE) wall projects. Research objectives were to assure (1) that variability in the corrosion properties of soil (pH, : ...

  2. Synthesis, crystal structure, near-IR photoelectric response of two 1-D selenides: [Cu2MSe5]·[Mn(H+-en)2(en)] (M=Ge, Sn)

    Science.gov (United States)

    Zhang, Yingying; Hu, Dandan; Yang, Huajun; Lin, Jian; Wu, Tao

    2017-07-01

    Reported here are two solvothermally synthesized metal selenides, namely [Cu2MSe5][Mn(H+-en)2(en)] (M = Ge (1) and Sn (2), and en=ethanediamine). The two isostructural compounds feature a 1-D anionic chain of [Cu2MSe5]4- with the existence of strong Cu•••Cu interaction. The estimated optical band gap was determined to be 1.69 eV for 1 and 1.49 eV for 2, indicating their semiconducting nature. Interestingly, 2 exhibits NIR-triggered photoelectric response, which make it potential semiconductor sensor used in photoelectric devices.

  3. Central bank independence and its effect on money market stability

    Directory of Open Access Journals (Sweden)

    MSc. Anera Alishani

    2012-06-01

    Full Text Available Since 1990s many countries have moved toward greater central bank independence (CBI by either amending their Central Bank’s laws or writing them de novo. Also countries of Western Balkans and many other transition countries have moved toward greater CBI. There are many potential benefits associated with greater CBI, and one of them is stable growth of money and liquidity. For a given level of money market development the hypothesis is that a more independent CB is likely to promote more stable growth of money supply (Dželetović et al., 2008. As a result the main research task of this work is to estimate the effects of CBI on money market growth for five Western Balkans countries and five other European transition countries. Because the empirical studies were very limited for the relationship between CBI and money market growth, there were no clear conclusions. In addition, there were different measuring methodologies that attempt to quantify the extent of legal and actual CBI. Related to the main research task, this dissertation has examined the effects of CBI on money market stability (proxied by bank deposit growth for a sample of 10 countries for a period from 1999-2009 by using fixed effect model. Through this methodology different regressions have been estimated, but the results were not robust and there are no clear finding on the relationship between CBI and money market growth.

  4. On the permanent hip-stabilizing effect of atmospheric pressure.

    Science.gov (United States)

    Prietzel, Torsten; Hammer, Niels; Schleifenbaum, Stefan; Kaßebaum, Eric; Farag, Mohamed; von Salis-Soglio, Georg

    2014-08-22

    Hip joint dislocations related to total hip arthroplasty (THA) are a common complication especially in the early postoperative course. The surgical approach, the alignment of the prosthetic components, the range of motion and the muscle tone are known factors influencing the risk of dislocation. A further factor that is discussed until today is atmospheric pressure which is not taken into account in the present THA concepts. The aim of this study was to investigate the impact of atmospheric pressure on hip joint stability. Five joint models (Ø 28-44 mm), consisting of THA components were hermetically sealed with a rubber capsule, filled with a defined amount of fluid and exposed to varying ambient pressure. Displacement and pressure sensors were used to record the extent of dislocation related to intraarticular and ambient pressure. In 200 experiments spontaneous dislocations of the different sized joint models were reliably observed once the ambient pressure was lower than 6.0 kPa. Increasing the ambient pressure above 6.0 kPa immediately and persistently reduced the joint models until the ambient pressure was lowered again. Displacement always exceeded half the diameter of the joint model and was independent of gravity effects. This experimental study gives strong evidence that the hip joint is permanently stabilized by atmospheric pressure, confirming the theories of Weber and Weber (1836). On basis of these findings the use of larger prosthetic heads, capsular repair and the deployment of an intracapsular Redon drain are proposed to substantially decrease the risk of dislocation after THA. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Effect of various teas on color stability of resin composites.

    Science.gov (United States)

    Dinç Ata, Gül; Gokay, Osman; Müjdeci, Arzu; Kivrak, Tugba Congara; Mokhtari Tavana, Armin

    2017-12-01

    To investigate the effect of various teas on color stability of resin composites. Two methacrylate-based (Arabesk Top, Grandio) and a silorane-based (Filtek Silorane) resin composites were used. 110 cylindrical samples of each resin composite were prepared (2 mm thickness and 8 mm diameter), polished and stored in distilled water (37°C for 24 hours). They were randomly divided into 11 groups (n= 10) and color measurements were taken. Then the samples were immersed in tap water (control), a black tea, a green tea or one of the eight herbal-fruit teas (37°C for 1 week) and subsequently subjected to the final color measurements. The color change of samples (ΔE*) was calculated, data were subjected to two-way ANOVA and Tukey's HSD tests. Teas, resin composites and their interactions were significant (P= 0.000). All the teas and control caused color changes in all three resin composites. Rosehip tea caused the most color changes, while tap water showed the least in all resin composites. Arabesk Top had the most staining potential in all the teas and control, whereas Filtek Silorane was the most stain resistant except Grandio immersed in sage tea. Color stability of all resin composites used were affected from both structure of resin materials and constituents of teas used. All resin composites were susceptible to staining by all teas especially rosehip tea. Arabesk Top composite showed the greatest color susceptibility in all teas and Filtek Silorane the least with one exception. Color of resin composites can be negatively affected from teas consumed. Clinicians should advise patients that drinking different kind of teas could intensify surface staining of resin based restorations.

  6. Effect of fixed aqueous layer thickness of polymeric stabilizers on zeta potential and stability of aripiprazole nanosuspensions.

    Science.gov (United States)

    Abdelbary, Aly A; Li, Xiaoling; El-Nabarawi, Mohamed; Elassasy, Abdelhalim; Jasti, Bhaskara

    2013-01-01

    The aim of this study was to evaluate the effect of the thickness of adsorbed polymer layer (also known as Fixed Aqueous Layer Thickness, FALT) of polymeric stabilizers on zeta potential and stability of nanoparticles in a suspension. Aripiprazole, a poorly water soluble drug was used as a model drug to evaluate rationale for increased FALT and to understand the effect of hydrophilicity and hydrophobicity of polymeric stabilizers on FALT of aripiprazole nanosuspensions. The nanosuspensions were prepared by media milling and Pluronic F68, Pluronic F127, Hydroxypropyl methylcellulose (HPMC) and Hydroxypropyl cellulose (HPC) were used as polymeric stabilizers. The particle size (immediately after preparation and after 1 week of storage at 25°C) and zeta potential of aripiprazole nanosuspensions were determined. For Pluronics, FALT was determined theoretically whereas for HPMC and HPC it was calculated as Debye Huckel parameter from the zeta potential dependence on the ionic strength. An increase in FALT resulted in reduced zeta potential. With an increase in FALT of polymers used, the stability of nanosuspensions showed improvement. Furthermore, a linear correlation was shown to exist between the FALT and length of hydrophilic chains in Pluronics.

  7. Contrasting effects of diversity on the temporal stability of plant populations

    NARCIS (Netherlands)

    Ruijven, van J.; Berendse, F.

    2007-01-01

    Recent theoretical and empirical work suggests that diversity enhances the temporal stability of a community. However, the effect of diversity on the stability of the individual populations within the community remains unclear. Some models predict a decrease of population stability with diversity,

  8. Steam Turbine Control Valve Stiction Effect on Power System Stability

    International Nuclear Information System (INIS)

    Halimi, B.

    2010-01-01

    One of the most important problems in power system dynamic stability is low frequency oscillations. This kind of oscillation has significant effects on the stability and security of the power system. In some previous papers, a fact was introduced that a steam pressure continuous fluctuation in turbine steam inlet pipeline may lead to a kind of low frequency oscillation of power systems. Generally, in a power generation plant, steam turbine system composes of some main components, i.e. a boiler or steam generator, stop valves, control valves and turbines that are connected by piping. In the conventional system, the turbine system is composed with a lot of stop and control valves. The steam is provided by a boiler or steam generator. In an abnormal case, the stop valve shuts of the steal flow to the turbine. The steam flow to the turbine is regulated by controlling the control valves. The control valves are provided to regulate the flow of steam to the turbine for starting, increasing or decreasing the power, and also maintaining speed control with the turbine governor system. Unfortunately, the control valve has inherent static friction (stiction) nonlinearity characteristics. Industrial surveys indicated that about 20-30% of all control loops oscillate due to valve problem caused by this nonlinear characteristic. In this paper, steam turbine control valve stiction effect on power system oscillation is presented. To analyze the stiction characteristic effect, firstly a model of control valve and its stiction characteristic are derived by using Newton's laws. A complete tandem steam prime mover, including a speed governing system, a four-stage steam turbine, and a shaft with up to for masses is adopted to analyze the performance of the steam turbine. The governor system consists of some important parts, i.e. a proportional controller, speed relay, control valve with its stiction characteristic, and stem lift position of control valve controller. The steam turbine has

  9. [Effects of colorants on yttria stabilized tetragonal zirconia polycrystals powder].

    Science.gov (United States)

    Wang, Bo; Chen, Jianfeng; Zhang, Yanchun; Wang, Ru

    2015-10-01

    To evaluate the effect of Fe2O3 and CeO2 as colorants on yttria stabilized tetragonal zirconia poly-crystals (Y-TZP) powder. The spray granulation slurry of colored zirconia was prepared with different concentrations of Fe2O3 (0.15%) and CeO2 (4%), which were added in Y-TZP. Zirconia powder was made by spray granulation. The powder specimens were divided into three groups: uncolored zirconia, Fe2O3 (0.15%) zirconia, and CeO2 (4%) zirconia. The particle morphologies of the powder specimens were measured with a laser particle size analyzer and an optical microscope. The differences in D50 among the three groups were statistically significant (PCeO2 and uncolored zirconia (PCeO2 (P>0.05). Mostly spherical powder was observed in the three groups. Fe2O3 as a colorant can affect particles, whereas CeO2 has no effect.

  10. Agglomeration of Celecoxib by Quasi Emulsion Solvent Diffusion Method: Effect of Stabilizer

    Directory of Open Access Journals (Sweden)

    Maryam Maghsoodi

    2016-12-01

    Full Text Available Purpose: The quasi-emulsion solvent diffusion (QESD has evolved into an effective technique to manufacture agglomerates of API crystals. Although, the proposed technique showed benefits, such as cost effectiveness, that is considerably sensitive to the choice of a stabilizer, which agonizes from a absence of systemic understanding in this field. In the present study, the combination of different solvents and stabilizers were compared to investigate any connections between the solvents and stabilizers. Methods: Agglomerates of celecoxib were prepared by QESD method using four different stabilizers (Tween 80, HPMC, PVP and SLS and three different solvents (methyl acetate, ethyl acetate and isopropyl acetate. The solid state of obtained particles was investigated by differential scanning calorimetry (DSC and Fourier transform infrared (FT-IR spectroscopy. The agglomerated were also evaluated in term of production yield, distribution of particles and dissolution behavior. Results: The results showed that the effectiveness of stabilizer in terms of particle size and particle size distribution is specific to each solvent candidate. A stabilizer with a lower HLB value is preferred which actually increased its effectiveness with the solvent candidates with higher lipophilicity. HPMC appeared to be the most versatile stabilizer because it showed a better stabilizing effect compared to other stabilizers in all solvents used. Conclusion: This study demonstrated that the efficiency of stabilizers in forming the celecoxib agglomerates by QESD was influenced by the HLB of the stabilizer and lipophilicity of the solvents.

  11. Effects of task and category membership on representation stability

    Directory of Open Access Journals (Sweden)

    Céline Manetta

    2011-01-01

    Full Text Available This study examined the within-subject stability of 150 participants who performed both a sorting task and a property-generation task over multiple sessions, focusing on three concrete concept categories (food, animals and bathroom products. We hypothesized that (1 the within-subject stability would be higher in the sorting task than in the property-generation task and (2 the nature of the category would influence both the within-subject stability of the classification groups in the sorting task and the properties generated to define these groups. The results show that the within-subject stability of conceptual representations depends both on the task and on the nature of the category. The stability of the representations was greater in the sorting task than in the property-generation task and in the food category. These results are discussed from a longitudinal perspective.

  12. WAEI/MSE: uma instância do processo WAE para micro e pequenas empresas de software = WAEI/MSE: an instance of the WAE process for micro and small software enterprises

    Directory of Open Access Journals (Sweden)

    Francisco Virginio Maracci

    2009-04-01

    Full Text Available Em Micro e Pequenas Empresas de Software (MPEs, geralmente, não há umprocesso sistemático de desenvolvimento de software. Um dos motivos é que essas empresas consideram os processos tradicionais extensos. Assim, normalmente, essas empresas são classificadas em nível 1 de maturidade do CMMI (Capability Maturity Model Integration. O objetivo deste artigo é apresentar uma instância do processo WAE (WebApplication Extension, a fim de auxiliar especificamente as MPEs que desenvolvem software Web a alavancarem o nível de capacidade de seu processo de desenvolvimento de software. A instância foi validada durante sua aplicação no desenvolvimento de um software comercialcom o apoio da Coordenadoria de Web da Unoeste e em outros três estudos de caso. In Micro and Small Enterprises (MSE of software, there is usuallynot a systematic software development process. One of the reasons is that these enterprises consider the traditional processes extensive. Thus, these enterprises are usually classified in level 1 of maturity of the CMMI (Capability Maturity Model Integration. The objective ofthis paper is to present a proposal for a software development process, in order to aid specifically MSEs that build Web software, to help them increase the capacity level of their processes. The process was validated during its application in development of software with the support of the Unoeste Web Coordination.

  13. Current aspects on bonding effectiveness and stability in adhesive dentistry.

    Science.gov (United States)

    Cardoso, M V; de Almeida Neves, A; Mine, A; Coutinho, E; Van Landuyt, K; De Munck, J; Van Meerbeek, B

    2011-06-01

    Improved dental adhesive technology has extensively influenced modern concepts in restorative dentistry. In light of minimal-invasive dentistry, this new approach promotes a more conservative cavity design, which basically relies on the effectiveness of current enamel-dentine adhesives. Nowadays, the interaction of adhesives with the dental substrate is based on two different strategies, commonly described as an etch-and-rinse and a self-etch approach. In an attempt to simplify the bonding technique, manufacturers have decreased the number of steps necessary for the accomplishment of the bonding procedure. As a consequence, two-step etch-and-rinse and one-step (self-etch) adhesives were introduced and gained rapid popularity in the dental market due to their claimed user-friendliness and lower technique sensitivity. However, many concerns have been raised on the bonding effectiveness of these simplified adhesives, especially in terms of durability, although this tends to be very material dependent. In order to blend all the adhesive components into one single solution, one-step adhesives were made more acidic and hydrophilic. Unfortunately, these properties induce a wide variety of seemingly unrelated problems that may jeopardize the effectiveness and stability of adhesion to the dental substrate. Being more susceptible to water sorption and thus nanoleakage, these adhesives are more prone to bond degradation and tend to fail prematurely as compared to their multi-step counterparts. Incidentally, another factor that may interfere with the bonding effectiveness of adhesives is the technique used for caries removal and cavity preparation. Several tools are on the market today to effectively remove carious tissue, thereby respecting the current trend of minimum intervention. Despite their promising performance, such techniques modify the tooth substrate in different aspects, possibly affecting bonding effectiveness. Altogether, we may conclude that not only the

  14. Effectiveness of electronic stability control on single-vehicle accidents.

    Science.gov (United States)

    Lyckegaard, Allan; Hels, Tove; Bernhoft, Inger Marie

    2015-01-01

    This study aims at evaluating the effectiveness of electronic stability control (ESC) on single-vehicle injury accidents while controlling for a number of confounders influencing the accident risk. Using police-registered injury accidents from 2004 to 2011 in Denmark with cars manufactured in the period 1998 to 2011 and the principle of induced exposure, 2 measures of the effectiveness of ESC were calculated: The crude odds ratio and the adjusted odds ratio, the latter by means of logistic regression. The logistic regression controlled for a number of confounding factors, of which the following were significant. For the driver: Age, gender, driving experience, valid driving license, and seat belt use. For the vehicle: Year of registration, weight, and ESC. For the accident surroundings: Visibility, light, and location. Finally, for the road: Speed limit, surface, and section characteristics. The present study calculated the crude odds ratio for ESC-equipped cars of getting in a single-vehicle injury accident as 0.40 (95% confidence interval [CI], 0.34-0.47) and the adjusted odds ratio as 0.69 (95% CI, 0.54-0.88). No difference was found in the effectiveness of ESC across the injury severity categories (slight, severe, and fatal). In line with previous results, this study concludes that ESC reduces the risk for single-vehicle injury accidents by 31% when controlling for various confounding factors related to the driver, the car, and the accident surroundings. Furthermore, it is concluded that it is important to control for human factors (at a minimum age and gender) in analyses where evaluations of this type are performed.

  15. Finite Larmor radius effects on the stability properties of internal modes of a z-pinch

    International Nuclear Information System (INIS)

    Aakerstedt, H.O.

    1987-01-01

    From the Vlasov-fluid model a set of approximate stability equations describing the stability of a cylindrically symmetric z-pinch is derived. The equations are derived in the limit of small gyroradius and include first order kinetic effects such as finite ion Larmor radius effects and resonant ion effects. Neglecting the resonant ion terms, we explicitly solve this set of equations for a constant current density profile leading to a dispersion relation. FLR effects are shown for the case of m=1 internal mode to be stabilizing and for large wavenumbers k, using a trial function approach, absolute stabilization is found. (author)

  16. The effect of curcumin on the stability of Aβ dimers.

    Science.gov (United States)

    Zhao, Li Na; Chiu, See-Wing; Benoit, Jérôme; Chew, Lock Yue; Mu, Yuguang

    2012-06-28

    Aβ oligomers are potential targets for the diagnosis and therapy of Alzheimer's disease (AD). On the other hand, the molecule curcumin has been shown to possess significant therapeutic potential in many areas. In this paper, we use all-atom explicit solvent molecular dynamics simulations to study the effect of curcumin on the stability of Aβ amyloid protein oligomers. We observed that curcumin decreases the β-sheet secondary structural content within the Aβ oligomers without reducing the contacts between the monomers. The breaking of the β-sheet is found to be preceded by a deformation of the β-sheet structure due to hydrophobic interaction from the nearby curcumin. Furthermore, the π-stacking interaction between curcumin (keto ring and enol ring) and the aromatic residues of Aβ, which exists throughout the simulations, has also contributed to the diminishing of the β-sheet structure. Our analysis of the underwrapped amide-carbonyl hydrogen bonds reveals several stable dehydrons of the oligomer, especially the dehydron pair 34L and 41I, which curcumin tends to hover over. We have examined the paths of curcumin on the Aβ proteins and determined the common routes where curcumin lingers as it traverses around the Aβ. In consequence, our study has provided a detailed interaction picture between curcumin and the Aβ oligomers.

  17. Toward the Effective Use of Military Veterinarians in Stability Operations

    National Research Council Canada - National Science Library

    Moore, Melinda; Fisher, Gail

    2008-01-01

    ... operations, all core missions and of equal importance. In active theaters such as Afghanistan and Iraq, medical civil-military stability operations figure prominently and include activities carried out by military veterinarians...

  18. Lactose in dairy ingredients: Effect on processing and storage stability.

    Science.gov (United States)

    Huppertz, Thom; Gazi, Inge

    2016-08-01

    Lactose is the main carbohydrate in the milk of most species. It is present in virtually all dry dairy ingredients, with levels ranging from lactose powders. The presence of lactose has a strong effect on ingredient processing and stability. Lactose can negatively influence powder properties and lead to undesirable effects, such as the stickiness of powder resulting in fouling during drying, or caking and related phenomena during storage. In addition, being a reducing carbohydrate, lactose can also participate in the Maillard reaction with free amino groups of proteins, peptides, and free AA. In this review, the influence of the presence (or absence) of lactose on physiochemical properties of dairy ingredients is reviewed, with particular emphasis on behavior during processing and storage. Particularly important features in this respect are whether lactose is in the (glassy) amorphous phase or in the crystalline phase, which is strongly affected by precrystallization conditions (e.g., in lactose, permeate, and whey powders) and by drying conditions. Furthermore, the moisture content and water activity of the ingredients are important parameters to consider, as they determine both mobility and reactivity, influencing Maillard reactions and concomitant browning, the crystallization of amorphous lactose during storage of dairy ingredients, glass transitions temperatures, and associated stickiness and caking phenomena. For the stickiness and caking, a crucial aspect to take into account is powder particle surface composition in relation to the bulk powder. Lactose is typically underrepresented at the powder surface, as a result of which deviations between observed lactose-induced caking and stickiness temperatures, and determined glass transition temperatures arise. By considering lactose as an integral part of ingredient composition along with all other compositional and environmental properties, lactose behavior in dairy ingredients can be understood, controlled, and

  19. Plutonium Stabilization in Zircon: Effects of Self-Radiation

    International Nuclear Information System (INIS)

    Weber, William J.; Hess, Nancy J.; Williford, Ralph E.; Heinisch, Howard L.; Begg, Bruce D.; Conradson, Steven D.; Ewing, Rodney C.; K.K.S. Pillay and K.C. Kim

    2000-01-01

    Zircon is the most thoroughly studied of all candidate ceramic phases for the stabilization of plutonium. Self-radiation damage from alpha-decay of the Pu can significantly affect the structure and properties of zircon. Two types of synthetic Pu-containing zircons, prepared in 1981, have provided an opportunity to characterize in detail the effects of Pu decay on the structure and properties of zircon and to make unique comparisons to observations of radiation effects in natural zircons. One set of zircon samples contained Pu-238; while the other set of samples contained Pu-239. In both instances, the Pu was substituted directly for Zr. The zircons containing Pu-238, with its 87.7 year half-life, provided a means of accelerating the alpha-decay rate by a factor of 250 when compared to the zircons containing Pu-239. Self-radiation from Pu decay in zircon results in the simultaneous accumulation of point defects and amorphous domains that eventually lead to a completely amorphous state. The swelling in zircon increases sigmoidally with dose and is well saturated at the highest dose. In all cases, the swelling can be accurately modeled based on the contributions from crystalline and amorphous components. Detailed X-ray absorption spectroscopy and X-ray diffraction methods have characterized the short-range and long-range structures of each zircon type. The amorphous state of zircon is consistent with the loss of long-range order and edge-sharing relationships between silica and zirconia polyhedra. Despite this, a distorted zircon structure and stoichiometry, which consists of silica and zirconia polyhedra that have rotated relative to each other, is retained over length scales up to 0.5 nm. Atomic-scale computer simulations have also been used to study defect accumulation and amorphization in zircon. The simulation results for the amorphous fraction as a function of alpha-decay dose are in excellent agreement with the experimental results

  20. Alignment and girder position of MSE septa in the new LSS4 extraction channel of the SPS

    CERN Document Server

    Balhan, B; Rizzo, A; Weterings, W; CERN. Geneva. SPS and LHC Division

    2002-01-01

    For the extraction of the beam from the Super Proton Synchrotron (SPS) to ring 2 of the Large Hadron Collider (LHC) and the CERN Neutrino to Gran Sasso (CNGS)facility, a new fast-extraction system is being constructed in the long straight section LSS4 of the SPS. Besides extraction bumpers, enlarged aperture quadrupoles and extraction kicker magnets (MKE), six conventional DC septum magnets (MSE) are used. These magnets are mounted on a single rigid support girder, pre-aligned so as to follow the trajectory of the extracted beam and optimise the available aperture. The girder has been motorised in order to optimise the local SPS aperture during setting up, so as to avoid the risk of circulating beam impact on the septum coils. In this note, we briefly present the trajectory and apertures of the beam, we describe the calculations and methods that have been used to determine the magnet position on the girder, and finally we report on the details of the girder movement and alignment.

  1. [Study on effect of demethoxycurcumin in Curcuma long on stability of curcumin].

    Science.gov (United States)

    Han, Gang; Bi, Rui; Le, Quan; Zhao, Lin-Lin; Dong, Yue; Lin, Qing-Hui

    2008-04-01

    To investigate effect of demethoxycurcumin on stability of curcumin. To add the demethoxycurcumin to pure curcumin, the change of curcumin was determined by HPLC and the dynamics of curcumin degradation was investigated. The stability both obtained from alcohol and demethoxycurcumin improved the stabilization of curcumin, the demi-period of curcumin prolonged with the addition of demethoxycurcumin. The commixture of curcumin and demethoxycurcumin are more stable than pure curcumin at the same conditions. Stability of curcumin is improved by demethoxycurcumin,it is crude stabilizing agent.

  2. [Study on effect of different extracts in curcuma long on stability of curcumin].

    Science.gov (United States)

    Han, Gang; Liu, Zheng-Meng; Wang, Xiao-Yan; Wang, Yan-Nan

    2007-05-01

    To investigate effects of different extracted fractions from Curcumia long on the stability of curcumin. There are some constituents that can stabilize curcumin. To add the extracts obtained from C. long were water, alcohol, acetone, ether, ethyl acetate, petroleum ether to pure solution of curcumin. To determine the change of curcumin by high performance liquid chromatography (HPLC). To investigate the dynamics of curcumin degradation. The stability obtained from alcohol, acetone, ether, ethyl ether all improved the stabilization of curcumin. 80% Alcohol extract had the optimal stabilizineg ability for curcumin. The extracts from alcohol are more stable than pure curcumin at same conditions. The stability of curcumin is improved by alcohol extracts.

  3. EFFECTIVENESS OF CORE STABILIZATION EXERCISES AND MOTOR CONTROL EXERCISES IN PATIENTS WITH LOW BACK ACHE

    OpenAIRE

    Vikranth .G .R; Lawrence Mathias; Mohd Meraj Ghori

    2015-01-01

    Background: Motor control exercises are isolated strengthening exercise for the deep spinal muscles (transverse abdominus, multifidus) whereas Core stability is achieved by global strengthening of the core muscles. There are not much studies available in the literature done or studied the short term effect of the motor control and core stabilization on subjects with low back pain. Therefore, the purpose of this study to find the comparative effect of motor control exercises versus core stabil...

  4. INVESTIGATION WITH MODAL ANALYSIS OF EFFECTS OF HIGH PV PENETRATION ON POWER SYSTEM VOLTAGE STABILITY

    OpenAIRE

    YILDIRIM, Burak

    2017-01-01

    This paper shows the effects of high PVintegration on the power system voltage stability. PV power plant was appliedto the IEEE 30 bus test system. Modal analysis method is used to show theeffect of PV integration on power system voltage stability. The power rate ofsynchronous generator in the IEEE 30 bus system is increased to show the powersystem stability effect of high PV penetration and then the PV generation withthe same power rate is connected appropriate bus in power system. The modal...

  5. Effects of polishing procedures on color stability of composite resins.

    Science.gov (United States)

    Güler, Ahmet Umut; Güler, Eda; Yücel, Ali Cağin; Ertaş, Ertan

    2009-01-01

    The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DeltaE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (alpha=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish

  6. Effects of polishing procedures on color stability of composite resins

    Directory of Open Access Journals (Sweden)

    Ahmet Umut Güler

    2009-04-01

    Full Text Available The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme. Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd, polishing discs then diamond polishing paste (PdP, polishing discs then a liquid polishing system (Biscover (PdB, and combinations of these (PdPB were used. Unpolished specimens served as the control (C. The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DE* were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (a=0.05. The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme. The posterior (Filtek P60 and universal (Filtek Z250 composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA, were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme and universal (Quadrant LC composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish

  7. Label-free LC-MSe in tissue and serum reveals protein networks underlying differences between benign and malignant serous ovarian tumors.

    Directory of Open Access Journals (Sweden)

    Wouter Wegdam

    Full Text Available PURPOSE: To identify proteins and (molecular/biological pathways associated with differences between benign and malignant epithelial ovarian tumors. EXPERIMENTAL PROCEDURES: Serum of six patients with a serous adenocarcinoma of the ovary was collected before treatment, with a control group consisting of six matched patients with a serous cystadenoma. In addition to the serum, homogeneous regions of cells exhibiting uniform histology were isolated from benign and cancerous tissue by laser microdissection. We subsequently employed label-free liquid chromatography tandem mass spectrometry (LC-MSe to identify proteins in these serum and tissues samples. Analyses of differential expression between samples were performed using Bioconductor packages and in-house scripts in the statistical software package R. Hierarchical clustering and pathway enrichment analyses were performed, as well as network enrichment and interactome analysis using MetaCore. RESULTS: In total, we identified 20 and 71 proteins that were significantly differentially expressed between benign and malignant serum and tissue samples, respectively. The differentially expressed protein sets in serum and tissue largely differed with only 2 proteins in common. MetaCore network analysis, however inferred GCR-alpha and Sp1 as common transcriptional regulators. Interactome analysis highlighted 14-3-3 zeta/delta, 14-3-3 beta/alpha, Alpha-actinin 4, HSP60, and PCBP1 as critical proteins in the tumor proteome signature based on their relative overconnectivity. The data have been deposited to the ProteomeXchange with identifier PXD001084. DISCUSSION: Our analysis identified proteins with both novel and previously known associations to ovarian cancer biology. Despite the small overlap between differentially expressed protein sets in serum and tissue, APOA1 and Serotransferrin were significantly lower expressed in both serum and cancer tissue samples, suggesting a tissue-derived effect in serum

  8. Effect of citronella essential oil fractions as oil phase on emulsion stability

    Science.gov (United States)

    Septiyanti, Melati; Meliana, Yenny; Agustian, Egi

    2017-11-01

    The emulsion system consists of water, oil and surfactant. In order to create stable emulsion system, the composition and formulation between water phase, surfactant and oil phase are very important. Essential oil such as citronella oil has been known as active ingredient which has ability as insect repellent. This research studied the effect of citronella oil and its fraction as oil phase on emulsion stability. The cycle stability test was conducted to check the emulsion stability and it was monitored by pH, density, viscosity, particle size, refractive index, zeta potential, physical appearance and FTIR for 4 weeks. Citronellal fraction has better stability compared to citronella oil and rhodinol fraction with slight change of physical and chemical properties before and after the cycle stability test. However, it is need further study to enhance the stability of the emulsion stability for this formulation.

  9. Effect of land use patterns on stability and distributions of organic ...

    African Journals Online (AJOL)

    user

    2011-10-10

    Oct 10, 2011 ... The objectives of this study were to elucidate the effects of different land use patterns on soil aggregate stability and the distribution of ... (Tisdall and Oades, 1982). The stability of aggregates has substantial effects on soil ..... economic benefits of owning them in study areas. Thus, rational land use was one ...

  10. Motional stark effect upgrades on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Rice, B.W.; Nilson, D.G.; Wroblewski, D.

    1994-04-01

    The measurement and control of the plasma current density profile (or q profile) is critical to the advanced tokamak program on DIII-D. A complete understanding of the stability and transport properties of advanced operating regimes requires detail poloidal field measurements over the entire plasma radius from the core to the edge. In support of this effort, the authors have recently completed an upgrade of the existing MSE diagnostic, increasing the number of channels from 8 to 16. A new viewing geometry has been added to the outer edge of the plasma which improves the radial resolution in this region from 10 cm to < 4 cm. This view requires the use of a reflector that has been designed to minimize polarization amplitude and phase effects. Vacuum-compatible polarizers have also been added to the instrument for in-situ calibration. Future use of the MSE diagnostic for feedback control of the q profile will also be discussed.

  11. Nonneutralized charge effects on tokamak edge magnetohydrodynamic stability

    International Nuclear Information System (INIS)

    Zheng, Linjin; Horton, W.; Miura, H.; Shi, T.H.; Wang, H.Q.

    2016-01-01

    Owing to the large ion orbits, excessive electrons can accumulate at tokamak edge. We find that the nonneutralized electrons at tokamak edge can contribute an electric compressive stress in the direction parallel to magnetic field by their mutual repulsive force. By extending the Chew–Goldburger–Low theory (Chew et al., 1956 [13]), it is shown that this newly recognized compressive stress can significantly change the plasma average magnetic well, so that a stabilization of magnetohydrodynamic modes in the pedestal can result. This linear stability regime helps to explain why in certain parameter regimes the tokamak high confinement can be rather quiet as observed experimentally.

  12. Grazing weakens temporal stabilizing effects of diversity in the Eurasian steppe.

    Science.gov (United States)

    Ren, Haiyan; Taube, Friedhelm; Stein, Claudia; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

    2018-01-01

    Many biodiversity experiments have demonstrated that plant diversity can stabilize productivity in experimental grasslands. However, less is known about how diversity-stability relationships are mediated by grazing. Grazing is known for causing species losses, but its effects on plant functional groups (PFGs) composition and species asynchrony, which are closely correlated with ecosystem stability, remain unclear. We conducted a six-year grazing experiment in a semi-arid steppe, using seven levels of grazing intensity (0, 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 sheep per hectare) and two grazing systems (i.e., a traditional, continuous grazing system during the growing period (TGS), and a mixed one rotating grazing and mowing annually (MGS)), to examine the effects of grazing system and grazing intensity on the abundance and composition of PFGs and diversity-stability relationships. Ecosystem stability was similar between mixed and continuous grazing treatments. However, within the two grazing systems, stability was maintained through different pathways, that is, along with grazing intensity, persistence biomass variations in MGS, and compensatory interactions of PFGs in their biomass variations in TGS. Ecosystem temporal stability was not decreased by species loss but rather remain unchanged by the strong compensatory effects between PFGs, or a higher grazing-induced decrease in species asynchrony at higher diversity, and a higher grazing-induced increase in the temporal variation of productivity in diverse communities. Ecosystem stability of aboveground net primary production was not related to species richness in both grazing systems. High grazing intensity weakened the temporal stabilizing effects of diversity in this semi-arid grassland. Our results demonstrate that the productivity of dominant PFGs is more important than species richness for maximizing stability in this system. This study distinguishes grazing intensity and grazing system from diversity effects on

  13. Detailed DFT studies of the electronic structure and optical properties of KBaMSe{sub 3} (M = As, Sb)

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Sikander; Khan, Saleem Ayaz; Khan, Wilayat [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Muhammad, Saleh; Udin, Haleem [Materials Modeling Lab, Department of Physics, Hazara University, Mansehra (Pakistan); Murtaza, G., E-mail: murtaza@icp.edu.pk [Materials Modeling Laboratory, Department of Physics, Islamia College University, Peshawar (Pakistan); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, Mascara 29000 (Algeria); Shah, Fahad Ali [Materials Modeling Lab, Department of Physics, Hazara University, Mansehra (Pakistan); Minar, Jan [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Ahmed, W.K. [ERU, College of Engineering, United Arab Emirates University, Al Ain (United Arab Emirates)

    2015-09-25

    Highlights: • The compounds are studied by FP-LAPW method within LDA, GGA, EV-GGA approximations. • All the compounds show indirect band gap nature. • Bonding nature is mixed covalent and ionic. • High absorption peaks and reflectivity ensures there utility in optoelectronic devices. - Abstract: Bonding nature as well as the electronic band structure, electronic charge density and optical properties of KBaMSe{sub 3} (M = As, Sb) compounds have been calculated using a full-potential augmented plane wave (FP-LAPW) method within the density functional theory. The exchange–correlation potential was handled with LDA and PBE-GGA approximations. Moreover, the Engel–Vosko generalized gradient approximation (EV-GGA) and the modified Beck–Johnson potential (mBJ) were also applied to improve the electronic band structure calculations. The study of band structure shows that KBaAsSe{sub 3}/KBaSbSe{sub 3} compounds have an indirect band gap of 2.08/2.10 eV which are in close agreement with the experimental data. The bonding nature has been studied as well using the electronic charge density (ECD) contour in the (1 0 1) crystallographic plane. It has been revealed that As/Sb–O atoms forms a strong covalent, while Ba–Se atoms form weak covalent bonding and the ionic bonding is mainly found between K and Ba atoms. Moreover, the complex dielectric function, absorption coefficient, refractive index, energy-loss spectrum and reflectivity have been estimated. From the reflectivity spectra, we found that KBaAsSe{sub 3} compound shows greater reflectivity than KBaSbSe{sub 3}, which means that KBaAsSe{sub 3} compound can be used as shielding material in visible and also in ultra violet region.

  14. Effect of nanoliposomes on the stabilization of incorporated retinol

    African Journals Online (AJOL)

    GREGORY

    2010-09-13

    Sep 13, 2010 ... vision, cellular differentiation, organ development during embryonic and fetal development, and membrane .... However, UV light did not significantly affect the stability of retinol in nanoliposomes. .... measurement of cholesterol-containing liposome on mica by atomic force microcopy. J. Colloid Interf. Sci.

  15. Driving-induced stability with long-range effects

    Czech Academy of Sciences Publication Activity Database

    Basu, U.; De Buyl, P.; Maes, Ch.; Netočný, Karel

    2016-01-01

    Roč. 115, č. 3 (2016), 1-7, č. článku 30007. ISSN 0295-5075 Institutional support: RVO:68378271 Keywords : stochastic thermodynamics * nonequilibrium steady states * stability enhancement Subject RIV: BE - Theoretical Physics Impact factor: 1.957, year: 2016

  16. Stability analysis of sandy slope considering anisotropy effect in ...

    Indian Academy of Sciences (India)

    1Faculty of Engineering, Azarbaijan Shahid Madani University, ... 2School of Civil Engineering, Iran University of Science and Technology, ..... material. 4.3 Stability analysis result. For each analysis case with specified geometrical configuration for slope, a wide range of slip surfaces are considered by establishing a grid of ...

  17. The effect of betaine on the foam stability: Molecular simulation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fengfeng [Chemistry Engineering Department, Zibo Vocational Institute, Zibo 255314 (China); Key laboratory of Colloid and Interface Chemistry, Shandong University, Jinan 250100 (China); Liu, Guokui [Key laboratory of Colloid and Interface Chemistry, Shandong University, Jinan 250100 (China); Yuan, Shiling, E-mail: shilingyuan@sdu.edu.cn [Key laboratory of Colloid and Interface Chemistry, Shandong University, Jinan 250100 (China)

    2017-06-15

    Highlights: • The reasons of betaine to enhance the stability of foam films are investigated by molecular simulation. • An electrostatic structure is formed at the air/water interface due to the electrostatic interaction. • The electrostatic structure becomes denser with the increasing concentration of betaine. - Abstract: Zwitterionic betaines are widely used as foam boosters due to these can enhance the stability of foam films. In this paper, mechanistic insights of betaine to improve the stability of alkyl-polyoxyethylene carboxylate (AEC) foam are provided by molecular simulation. In the simulation, we observe the electropositive nitrogen atoms in betaine interact with the electronegative sulfur atoms, an electrostatic structure is formed at the air/water interface. Interaction energies of the mixed surfactants are calculated by the quantum chemistry methods. The calculations show betaine-AEC and betaine–betaine possess attractive interaction, and that AEC–AEC has repulsion to each other. In the other words, the repulsion between the headgroups of anionic surfactants is relaxed by betaine. Additionally, the influence of concentration of betaine on the stability of foam films is also simulated. The RDF and coordination numbers show that the electrostatic structures become denser with the increasing concentration of betaine. Therefore, entry barrier is enhanced accordingly. The SMD simulation also demonstrates the same variation tendency of entry barrier. The simulation details provide vital supplements to experiments.

  18. Grazing weakens temporal stabilizing effects of diversity in the Eurasian steppe

    OpenAIRE

    Ren, Haiyan; Taube, Friedhelm; Stein, Claudia; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

    2017-01-01

    Abstract Many biodiversity experiments have demonstrated that plant diversity can stabilize productivity in experimental grasslands. However, less is known about how diversity–stability relationships are mediated by grazing. Grazing is known for causing species losses, but its effects on plant functional groups (PFGs) composition and species asynchrony, which are closely correlated with ecosystem stability, remain unclear. We conducted a six‐year grazing experiment in a semi‐arid steppe, usin...

  19. Stochastic description of compounds stability under irradiation: Temperature, flux and cascade size effects

    International Nuclear Information System (INIS)

    Doan, N.V.; Martin, G.; Haider, F.; Bellon, P.

    1989-01-01

    Assessing cascade size effects on compound stability under irradiation requires a safe stochastic description of the order-disorder transition under external forcing. To address multidimensional order parameter structures, we introduce the Kubo Ansatz technique and apply it to the FCC lattice. Irradiation-induced stabilization of unexpected structures is predicted: a diagram for the respective stability of L1 2 , L1 0 and disordered FCC solid solution is established

  20. STATCOM's Effects on Stability Improvement of Induction Generator based Wind Turbine Systems

    DEFF Research Database (Denmark)

    Hu, Y; Chen, Zhe

    2009-01-01

    Large number of wind turbines are being installed and connected to power systems. In some countries or networks, the penetration level of wind power is significant high so as to affect the power system operation and control. Consequently, the stable operation of wind turbine systems is very impor...... important for power system stability. This paper studies the effect of STATCOM on stability improvement of a wind turbine system. The function of the STATCOM in improving the system stability has been demonstrated....

  1. Crowding effect on helix-coil transition: Beyond entropic stabilization

    International Nuclear Information System (INIS)

    Koutsioubas, A.; Lairez, D.; Combet, S.; Longeville, S.; Fadda, G. C.; Zalczer, G.

    2012-01-01

    We report circular dichroism measurements on the helix-coil transition of poly(L-glutamic acid) in solution with polyethylene glycol (PEG) as a crowding agent. The PEG solutions have been characterized by small angle neutron scattering and are well described by the picture of a network of mesh size ξ, usual for semi-dilute chains in good solvent. We show that the increase of PEG concentration stabilizes the helices and increases the transition temperature. But more unexpectedly, we also notice that the increase of concentration of crowding agent reduces the mean helix extent at the transition, or in other words reduces its cooperativity. This result cannot be taken into account for by an entropic stabilization mechanism. Comparing the mean length of helices at the transition and the mesh size of the PEG network, our results strongly suggest two regimes: helices shorter or longer than the mesh size.

  2. Stabilization effect of fission source in coupled Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Borge; Dufek, Jan [Div. of Nuclear Reactor Technology, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm (Sweden)

    2017-08-15

    A fission source can act as a stabilization element in coupled Monte Carlo simulations. We have observed this while studying numerical instabilities in nonlinear steady-state simulations performed by a Monte Carlo criticality solver that is coupled to a xenon feedback solver via fixed-point iteration. While fixed-point iteration is known to be numerically unstable for some problems, resulting in large spatial oscillations of the neutron flux distribution, we show that it is possible to stabilize it by reducing the number of Monte Carlo criticality cycles simulated within each iteration step. While global convergence is ensured, development of any possible numerical instability is prevented by not allowing the fission source to converge fully within a single iteration step, which is achieved by setting a small number of criticality cycles per iteration step. Moreover, under these conditions, the fission source may converge even faster than in criticality calculations with no feedback, as we demonstrate in our numerical test simulations.

  3. Effect of flow rate on stability of unconsolidated producing sands

    Energy Technology Data Exchange (ETDEWEB)

    Tippie, D.B.; Kohlhaas, C.A.

    1973-01-01

    Stabilization of unconsolidated sand during production by sand arching was confirmed with a sandpack model of a well completion. Fluid was flowed radially through a sand pack which was loaded vertically to simulate overburden pressure. Flow rates were gradually increased to the point at which sand flowed and the arch then examined. Larger arches resulted from higher flow rates. Critical rate for the sand production depended on rate history as well as rate magnitude and arch size.

  4. The effects of tether placement on antibody stability on surfaces

    Science.gov (United States)

    Grawe, Rebecca W.; Knotts, Thomas A.

    2017-06-01

    Despite their potential benefits, antibody microarrays have fallen short of performing reliably and have not found widespread use outside of the research setting. Experimental techniques have been unable to determine what is occurring on the surface of an atomic level, so molecular simulation has emerged as the primary method of investigating protein/surface interactions. Simulations of small proteins have indicated that the stability of the protein is a function of the residue on the protein where a tether is placed. The purpose of this research is to see whether these findings also apply to antibodies, with their greater size and complexity. To determine this, 24 tethering locations were selected on the antibody Protein Data Bank (PDB) ID: 1IGT. Replica exchange simulations were run on two different surfaces, one hydrophobic and one hydrophilic, to determine the degree to which these tethering sites stabilize or destabilize the antibody. Results showed that antibodies tethered to hydrophobic surfaces were in general less stable than antibodies tethered to hydrophilic surfaces. Moreover, the stability of the antibody was a function of the tether location on hydrophobic surfaces but not hydrophilic surfaces.

  5. Enhancing effect of calcium and vanadium ions on thermal stability of bromoperoxidase from Corallina pilulifera.

    Science.gov (United States)

    Garcia-Rodriguez, Esther; Ohshiro, Takashi; Aibara, Toshiaki; Izumi, Yoshikazu; Littlechild, Jennifer

    2005-05-01

    Bromoperoxidase from the macro-alga Corallina pilulifera is an enzyme that possesses vanadate in the catalytic center, and shows a significant thermostability and stability toward organic solvents. The structural analysis of the recombinant enzyme overexpressed in yeast revealed that it contains one calcium atom per subunit. This has been confirmed by inductively coupled plasma emission spectrometry experiments. The study of the effect of metal ions on the apo-enzyme stability has shown that the calcium ion significantly increased the enzyme stability. In addition, vanadate also increased the thermostability and strontium and magnesium ions had similar effects as calcium. The holo-enzyme shows high stability in a range of organic solvents. The effect of the different ions and solvents on the structure of the enzyme has been studied by circular dichroism experiments. The high stability of the enzyme in the presence of organic solvents is useful for its application as a biocatalyst.

  6. Effect of corner radius in stabilizing the low-Re flow past a cylinder

    KAUST Repository

    Zhang, Wei

    2017-08-03

    We perform global linear stability analysis on low-Re flow past an isolated cylinder with rounded corners. The objective of the present work is to investigate the effect of the cylinder geometry (corner radius) on the stability characteristics of the flow. Our investigation sheds light on new physics that the flow can be stabilized by partially rounding the cylinder in the critical and weakly super-critical flow regimes. The flow is first stabilized and then gradually destabilized as the cylinder varies from square to circular geometry. The sensitivity analysis reveals that the variation of stability is attributed to the different spatial variation trends of the backflow velocity in the near- and far-wake regions for various cylinder geometries. The results from the stability analysis are also verified with those of the direct simulations and very good agreement is achieved.

  7. Molten salt extraction (MSE) of americium from plutonium metal in CaCl2-KCl-PuCl3 and CaCl2-PuCl3 salt systems

    International Nuclear Information System (INIS)

    Dodson, K.E.

    1992-01-01

    Molten salt extraction (MSE) of americium-241 from reactor-grade plutonium has been developed using plutonium trichloride salt in stationary furnaces. Batch runs with oxidized and oxide-free metal have been conducted at temperature ranges between 750 and 945C, and plutonium trichloride concentrations from one to one hundred mole percent. Salt-to-metal ratios of 0.10, 0.15, and 0 30 were examined. The solvent salt was either eutectic 74 mole percent CaCl 2 endash 26 mole percent KCl or pure CaCl 2 . Evidence of trivalent product americium, and effects of temperature, salt-to-metal ratio, and oxide contamination on the americium extraction efficiency are given. 24 refs, 20 figs, 13 tabs

  8. UPLC-MSE Profiling of Phytoplankton Metabolites: Application to the Identification of Pigments and Structural Analysis of Metabolites in Porphyridium purpureum

    Directory of Open Access Journals (Sweden)

    Camille Juin

    2015-04-01

    Full Text Available A fast and high-resolution UPLC-MSE analysis was used to identify phytoplankton pigments in an ethanol extract of Porphyridium purpureum (Pp devoid of phycobiliproteins. In a first step, 22 standard pigments were analyzed by UPLC-MSE to build a database including retention time and accurate masses of parent and fragment ions. Using this database, seven pigments or derivatives previously reported in Pp were unequivocally identified: β,β-carotene, chlorophyll a, zeaxanthin, chlorophyllide a, pheophorbide a, pheophytin a, and cryptoxanthin. Minor amounts of Divinyl chlorophyll a, a chemotaxonomic pigment marker for prochlorophytes, were also unequivocally identified using the database. Additional analysis of ionization and fragmentation patterns indicated the presence of ions that could correspond to hydroxylated derivatives of chlorophyll a and pheophytin a, produced during the ethanolic extraction, as well as previously described galactosyldiacylglycerols, the thylakoid coenzyme plastoquinone, and gracilamide B, a molecule previously reported in the red seaweed Gracillaria asiatica. These data point to UPLC-MSE as an efficient technique to identify phytoplankton pigments for which standards are available, and demonstrate its major interest as a complementary method for the structural elucidation of ionizable marine molecules.

  9. Effect of transition metal ions on the conductivity and stability of stabilized zirconia

    DEFF Research Database (Denmark)

    Lybye, D.; Mogensen, Mogens Bjerg

    2007-01-01

    operation temperatures and changes in temperature or oxygen partial pressure together with long-term operation are seen to induce partial destabilisation and even phase changes. In order to avoid these effects co-doping has proven helpful. Based on experimental data available in literature, we discus...

  10. Exploitation of the complex chemistry of hindered amine stabilizers in effective plastics stabilization

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Jan; Pilař, Jan; Nešpůrek, Stanislav

    2007-01-01

    Roč. 13, č. 3 (2007), s. 119-132 ISSN 1083-5601. [International Plastics Additives and Modifiers Conference Addcon World /12./. Cologne, 17.10.2006-18.10.2006] R&D Projects: GA AV ČR KAN400720701 Institutional research plan: CEZ:AV0Z40500505 Keywords : HAS mechanism * thermostabilizing effect * HAS deactivation by acids Subject RIV: CA - Inorganic Chemistry Impact factor: 0.685, year: 2007

  11. The effect of platelet-rich fibrin on implant stability.

    Science.gov (United States)

    Öncü, Elif; Alaaddinoğlu, E Emine

    2015-01-01

    Achieving accelerated implant osseointegration could make immediate or early loading of implants more predictable. Platelet-rich fibrin (PRF) is frequently used to accelerate soft and hard tissue healing. The activated platelets in PRF release growth factors, resulting in cellular proliferation, collagen synthesis, and osteoid production. The aim of this study was to compare the stability of dental implants inserted in a one-stage surgical protocol with or without PRF application. Twenty healthy patients with adequate alveolar bone and two or more adjacent missing teeth extracted at least 6 months previously were included in this study. A minimum of two tapered implants (Ankylos, Dentsply/Friadent) were placed in each patient. After surgical preparation of the implant sockets, PRF that had been prepared preoperatively was placed randomly into one of the sockets (PRF+). The acellular plasma portion of PRF was used to wet the implant placed into the PRF-coated socket. Resonance frequency measurements were made after implant placement and at 1 week and 1 month postoperatively. Mean implant stability quotients (ISQs) of the PRF+ implants was 69.3 ± 10.5, and mean ISQs for the PRF- implants was 64.5 ± 12.2 at the end of the first week. The mean ISQs at 4 weeks postoperatively were 77.1 ± 7.1 for the PRF+ group and 70.5 ± 7.7 for the PRF- group. In this study, PRF application increased implant stability during the early healing period, as evidenced by higher ISQ values. Simple application of this material seems to provide faster osseointegration.

  12. Effect of asynchronous updating on the stability of cellular automata

    International Nuclear Information System (INIS)

    Baetens, J.M.; Van der Weeën, P.; De Baets, B.

    2012-01-01

    Highlights: ► An upper bound on the Lyapunov exponent of asynchronously updated CA is established. ► The employed update method has repercussions on the stability of CAs. ► A decision on the employed update method should be taken with care. ► Substantial discrepancies arise between synchronously and asynchronously updated CA. ► Discrepancies between different asynchronous update schemes are less pronounced. - Abstract: Although cellular automata (CAs) were conceptualized as utter discrete mathematical models in which the states of all their spatial entities are updated simultaneously at every consecutive time step, i.e. synchronously, various CA-based models that rely on so-called asynchronous update methods have been constructed in order to overcome the limitations that are tied up with the classical way of evolving CAs. So far, only a few researchers have addressed the consequences of this way of updating on the evolved spatio-temporal patterns, and the reachable stationary states. In this paper, we exploit Lyapunov exponents to determine to what extent the stability of the rules within a family of totalistic CAs is affected by the underlying update method. For that purpose, we derive an upper bound on the maximum Lyapunov exponent of asynchronously iterated CAs, and show its validity, after which we present a comparative study between the Lyapunov exponents obtained for five different update methods, namely one synchronous method and four well-established asynchronous methods. It is found that the stability of CAs is seriously affected if one of the latter methods is employed, whereas the discrepancies arising between the different asynchronous methods are far less pronounced and, finally, we discuss the repercussions of our findings on the development of CA-based models.

  13. Thermal stability for the effective use of commercial catalase

    Directory of Open Access Journals (Sweden)

    Miłek J.

    2014-12-01

    Full Text Available Catalase with the commercial catalase name Terminox Ultra is widely used in the textile industry in bleaching processes. This enzyme is used to catalyse the decomposition of residual hydrogen peroxide into oxygen and water. In this study catalase was kept for about 30 hours in water baths in a temperature range from 35 to 70°C. For the first time, the kinetics of thermal deactivation of this enzyme was examined using an oxygen electrode. Stability of the enzyme depends strongly on temperature and its half-life times are 0.0014 h and 7.6 h, at 35 and 70°C, respectively.

  14. Gravitational stability and screening effect from D extra timelike dimensions

    International Nuclear Information System (INIS)

    Matsuda, Satoshi; Seki, Shigenori

    2001-01-01

    We study (3+1)+D dimensional spacetime, where D extra dimensions are timelike. Compactification of the D timelike dimensions leads to tachyonic Kaluza-Klein gravitons. We calculate the gravitational self-energies of massive spherical bodies due to the tachyonic exchange, discuss their stability, and find that the gravitational force is screened in a certain number of the extra dimensions. We also derive the exact relationship between the Newton constants in the full (4+D)-dimensional spacetime with the D extra times and the ordinary Newton constant of our 4-dimensional world

  15. An Effective Distributed Model for Power System Transient Stability Analysis

    Directory of Open Access Journals (Sweden)

    MUTHU, B. M.

    2011-08-01

    Full Text Available The modern power systems consist of many interconnected synchronous generators having different inertia constants, connected with large transmission network and ever increasing demand for power exchange. The size of the power system grows exponentially due to increase in power demand. The data required for various power system applications have been stored in different formats in a heterogeneous environment. The power system applications themselves have been developed and deployed in different platforms and language paradigms. Interoperability between power system applications becomes a major issue because of the heterogeneous nature. The main aim of the paper is to develop a generalized distributed model for carrying out power system stability analysis. The more flexible and loosely coupled JAX-RPC model has been developed for representing transient stability analysis in large interconnected power systems. The proposed model includes Pre-Fault, During-Fault, Post-Fault and Swing Curve services which are accessible to the remote power system clients when the system is subjected to large disturbances. A generalized XML based model for data representation has also been proposed for exchanging data in order to enhance the interoperability between legacy power system applications. The performance measure, Round Trip Time (RTT is estimated for different power systems using the proposed JAX-RPC model and compared with the results obtained using traditional client-server and Java RMI models.

  16. Stabilization effect of fission source in coupled Monte Carlo simulations

    Directory of Open Access Journals (Sweden)

    Börge Olsen

    2017-08-01

    Full Text Available A fission source can act as a stabilization element in coupled Monte Carlo simulations. We have observed this while studying numerical instabilities in nonlinear steady-state simulations performed by a Monte Carlo criticality solver that is coupled to a xenon feedback solver via fixed-point iteration. While fixed-point iteration is known to be numerically unstable for some problems, resulting in large spatial oscillations of the neutron flux distribution, we show that it is possible to stabilize it by reducing the number of Monte Carlo criticality cycles simulated within each iteration step. While global convergence is ensured, development of any possible numerical instability is prevented by not allowing the fission source to converge fully within a single iteration step, which is achieved by setting a small number of criticality cycles per iteration step. Moreover, under these conditions, the fission source may converge even faster than in criticality calculations with no feedback, as we demonstrate in our numerical test simulations.

  17. Investigation of the effects of human body stability on joint angles’ prediction

    Energy Technology Data Exchange (ETDEWEB)

    Pasha Zanoosi, A. A., E-mail: aliakbar.pasha@yahoo.com, E-mail: aliakbar.pasha@qiau.ac.ir [Islamic Azad University, Faculty of Industrial & Mechanical Engineering, Qazvin Branch (Iran, Islamic Republic of); Naderi, D.; Sadeghi-Mehr, M.; Feri, M. [Bu Ali-Sina University, Mechanical Engineering Department, Faculty of Engineering (Iran, Islamic Republic of); Beheshtiha, A. Sh. [Leibniz Universität Hannover, Institute of Mechanics and Computational Mechanics (Germany); Fallahnejad, K. [Flinders University, Discipline of Mechanical Engineering, School of Computer Science, Engineering and Mathematics (Australia)

    2015-10-15

    Loosing stability control in elderly or paralyzed has motivated researchers to study how a stability control system works and how to determine its state at every time instant. Studying the stability of a human body is not only an important problem from a scientific viewpoint, but also finally leads to new designs of prostheses and orthoses and rehabilitation methods. Computer modeling enables researchers to study and describe the reactions and propose a suitable and optimized motion pattern to strengthen the neuromuscular system and helps a human body maintain its stability. A perturbation as a tilting is exposed to an underfoot plate of a musculoskeletal model of the body to study the stability. The studied model of a human body included four links and three degrees of freedom with eight muscles in the sagittal plane. Lagrangian dynamics was used for deriving equations of motion and muscles were modeled using Hill’s model. Using experimental data of joint trajectories for a human body under tilting perturbation, forward dynamics has been applied to predict joint trajectories and muscle activation. This study investigated the effects of stability on predicting body joints’ motion. A new stability function for a human body, based on the zero moment point, has been employed in a forward dynamics procedure using a direct collocation method. A multi-objective optimization based on genetic algorithm has been proposed to employ stability as a robotic objective function along with muscle stresses as a biological objective function. The obtained results for joints’ motion were compared to experimental data. The results show that, for this type of perturbations, muscle stresses are in conflict with body stability. This means that more body stability requires more stresses in muscles and reverse. Results also show the effects of the stability objective function in better prediction of joint trajectories.

  18. Investigation of the effects of human body stability on joint angles’ prediction

    International Nuclear Information System (INIS)

    Pasha Zanoosi, A. A.; Naderi, D.; Sadeghi-Mehr, M.; Feri, M.; Beheshtiha, A. Sh.; Fallahnejad, K.

    2015-01-01

    Loosing stability control in elderly or paralyzed has motivated researchers to study how a stability control system works and how to determine its state at every time instant. Studying the stability of a human body is not only an important problem from a scientific viewpoint, but also finally leads to new designs of prostheses and orthoses and rehabilitation methods. Computer modeling enables researchers to study and describe the reactions and propose a suitable and optimized motion pattern to strengthen the neuromuscular system and helps a human body maintain its stability. A perturbation as a tilting is exposed to an underfoot plate of a musculoskeletal model of the body to study the stability. The studied model of a human body included four links and three degrees of freedom with eight muscles in the sagittal plane. Lagrangian dynamics was used for deriving equations of motion and muscles were modeled using Hill’s model. Using experimental data of joint trajectories for a human body under tilting perturbation, forward dynamics has been applied to predict joint trajectories and muscle activation. This study investigated the effects of stability on predicting body joints’ motion. A new stability function for a human body, based on the zero moment point, has been employed in a forward dynamics procedure using a direct collocation method. A multi-objective optimization based on genetic algorithm has been proposed to employ stability as a robotic objective function along with muscle stresses as a biological objective function. The obtained results for joints’ motion were compared to experimental data. The results show that, for this type of perturbations, muscle stresses are in conflict with body stability. This means that more body stability requires more stresses in muscles and reverse. Results also show the effects of the stability objective function in better prediction of joint trajectories

  19. The effectiveness of core stabilization exercise in adolescent idiopathic scoliosis: A randomized controlled trial.

    Science.gov (United States)

    Gür, Gözde; Ayhan, Cigdem; Yakut, Yavuz

    2017-06-01

    Core stabilization training is used to improve postural balance in musculoskeletal problems. The purpose of this study was to investigate the effectiveness of stabilization training in adolescent idiopathic scoliosis. A randomized controlled trial, pretest-posttest design. In total, 25 subjects with adolescent idiopathic scoliosis were randomly divided into two groups: stabilization group ( n = 12) and control group ( n = 13). The stabilization group received core stabilization in addition to traditional rehabilitation, and the control group received traditional rehabilitation for 10 weeks. Assessment included Cobb's angle on radiograph, apical vertebral rotation in Adam's test, trunk asymmetry (Posterior Trunk Symmetry Index), cosmetic trunk deformity (Trunk Appearance Perception Scale), and quality of life (Scoliosis Research Society-22 questionnaire). Inter-group comparisons showed significantly greater improvements in the mean change in lumbar apical vertebral rotation degree and the pain domain of Scoliosis Research Society-22 in the stabilization group than those in the control group ( p adolescent idiopathic scoliosis. Clinical relevance Stabilization exercises are more effective in reducing rotation deformity and pain than traditional exercises in the conservative rehabilitation of adolescent idiopathic scoliosis. These improvements suggest that stabilization training should be added to rehabilitation programs in adolescent idiopathic scoliosis.

  20. Experimental research of "microcable in a microconduct" system stability to effect of freezing water

    Science.gov (United States)

    Andreev, Vladimir A.; Burdin, Vladimir A.; Nikulina, Tatiana G.; Alekhin, Ivan N.; Gavryushin, Sergey A.; Nikulin, Aleksey G.; Praporshchikov, Denis E.

    2011-12-01

    Results of experimental researches of "optical microcable in a microduct" system stability to effect of freezing water are presented. It is shown this system is steadier to water freezing in comparison to lighten optical cable in protective polymer tube.

  1. Polyvinylpyrrolidone Matrix as an Effective Reducing Agent and Stabilizer during Reception of Silver Nanoparticles in Composites

    OpenAIRE

    Semenyuk, Nataliya; Kostiv, Ulyana; Dudok, Galyna; Nechay, Jaroslav; Skorokhoda, Volodymyr

    2013-01-01

    The use of polyvinylpyrrolidone matrix as an effective reducing agent and stabilizer during reception of silver nanoparticles in composites is substantiated. The influence of various factors on patterns of obtaining silver nanoparticles and their size.

  2. Stabilization and destabilization effects of the electric field on stochastic precipitate pattern

    NARCIS (Netherlands)

    Lagzi, István; Izsak, F.

    2004-01-01

    Stabilization and destabilization effects of an applied electric field on the Liesegang pattern formation in low concentration gradient were studied with numerical model simulations. In the absence of an electric field pattern formation exhibits increasingly stochastic behaviour as the initial

  3. SURFACE CHEMICAL EFFECTS ON COLLOID STABILITY AND TRANSPORT THROUGH NATURAL POROUS MEDIA

    Science.gov (United States)

    Surface chemical effects on colloidal stability and transport through porous media were investigated using laboratory column techniques. Approximately 100 nm diameter, spherical, iron oxide particles were synthesized as the mobile colloidal phase. The column packing material was ...

  4. Strong Effect of Azodye Layer Thickness on RM-Stabilized Photoalignment

    Science.gov (United States)

    2017-05-21

    Strong Effect of Azodye Layer Thickness on RM-Stabilized Photoalignment Colin McGinty*, Valerie Finnemeyer**, Robert Reich**, Harry Clark...vertical alignment on these substrates. For the thinner BY layers, we do not see this strong evidence of out of plane reorientation. The out of...In this report we show the surprising effect that thin azodye layers demonstrate improved stability over those that are thicker. Figure 6

  5. The Effects of Organosulfur Compounds upon the Storage Stability of Jet A Fuel

    Science.gov (United States)

    1981-08-14

    0 The Effects of Organosulfur Compounds Upon the Storage Stability of Jet A Fuel,, Cpt., Frederick C. Heneman HQDA, MTLPERCEN (bAPC-OPP-E) 200...CLASSIFICATION OF THIS PAGE(Wen Data nterd) V-%. T-2503 THE EFFECTS OF ORGANOSULFUR COMPOUNDS UPON THE STORAGE STABILITY OF JET A FUEL Ac-s ion For 7 Di... organosulfur bases was developed via measurement of their resonance chemical shifts in proton NMR. Linear plots of log gm. deposit vs. change in chemical shift

  6. Effect of natural polyphenol on the oxidative stability of pecan oil.

    Science.gov (United States)

    Zhang, Yuan-Yuan; Zhang, Fang; Thakur, Kiran; Ci, Ao-Te; Wang, Hao; Zhang, Jian-Guo; Wei, Zhao-Jun

    2017-10-05

    We evaluated the antioxidant activity of natural polyphenols which gives high oxidative stability to the pecan oil. The in vitro DPPH radical scavenging, reducing power and total antioxidant activity of tested antioxidants demonstrated that tannic acid displayed the highest DPPH scavenging activity and provided the largest reducing power. During storage of pecan oil, based on oxidative stability tests, we further evaluated the protective effect of polyphenols and synthetic antioxidants on the oxidative stability of pecan oil. The results showed that caffeic acid inhibited oxidation of pecan oil effectively. Sesamol and catechin showed slight improvement in oxidative stability, while ferulic acid, erucic acid and rutin had no effect. Taken together, compared with synthetic antioxidants (TBHQ, BHT, BHA), caffeic acid was observed to be stronger than BHT and BHA and was close to TBHQ. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Tilt mode stability scaling in field-reversed configurations with finite Larmor radius effect

    International Nuclear Information System (INIS)

    Iwasawa, Naotaka; Ishida, Akio; Steinhauer, Loren C.

    2000-01-01

    The marginal stability of a static plasma with finite-Larmor-radius (FLR) effects depends on a combination of the FLR effect and the ideal magnetohydrodynamic (MHD) potential energy. For the tilt mode in a field-reversed configuration (FRC) previous computations of these two factors led to a prediction of stability for S * ≤(3-5)E where S * is the macroscale parameter (separatrix radius/ion skin depth) and E is the elongation (separatrix half length/separatrix radius). This prediction explained the observed stability of most experiments. However, recent computations of actual MHD eigenfunctions indicate that the MHD growth rate has a much weaker scaling with elongation than previously believed. As a consequence, most of the long-lived, stable FRC experiments lie in the region predicted to be unstable. It appears then that the stability of FRC experiments is not explained by FLR effects in a static equilibrium. (c) 2000 American Institute of Physics

  8. Effect of arm swing strategy on local dynamic stability of human gait.

    Science.gov (United States)

    Punt, Michiel; Bruijn, Sjoerd M; Wittink, Harriet; van Dieën, Jaap H

    2015-02-01

    Falling causes long term disability and can even lead to death. Most falls occur during gait. Therefore improving gait stability might be beneficial for people at risk of falling. Recently arm swing has been shown to influence gait stability. However at present it remains unknown which mode of arm swing creates the most stable gait. To examine how different modes of arm swing affect gait stability. Ten healthy young male subjects volunteered for this study. All subjects walked with four different arm swing instructions at seven different gait speeds. The Xsens motion capture suit was used to capture gait kinematics. Basic gait parameters, variability and stability measures were calculated. We found an increased stability in the medio-lateral direction with excessive arm swing in comparison to normal arm swing at all gait speeds. Moreover, excessive arm swing increased stability in the anterior-posterior and vertical direction at low gait speeds. Ipsilateral and inphase arm swing did not differ compared to a normal arm swing. Excessive arm swing is a promising gait manipulation to improve local dynamic stability. For excessive arm swing in the ML direction there appears to be converging evidence. The effect of excessive arm swing on more clinically relevant groups like the more fall prone elderly or stroke survivors is worth further investigating. Excessive arm swing significantly increases local dynamic stability of human gait. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Effect of Shot Peening on the Fatigue Strength of Automotive Tubular Stabilizer Bars DC 218

    Directory of Open Access Journals (Sweden)

    Wittek A.M.

    2016-12-01

    Full Text Available This paper concerns issues related to the development of designs of stabilizer bars for new motor vehicle models. It involves not only the designing of a stabilizer bar with the shape required by the manufacturer, but also the preparation of bending and heat treatment processes as well as the performance of strength and fatigue tests. In the prototype development phase, the simulations techniques (FEM may be used to assess the design. The article contains a detailed analysis of a stabilizer bar designated with the DC 218 VA symbol. Performed numerical strength and fatigue calculations showed that the developed stabilizer bar design with the desired shape did not achieve the required number of fatigue cycles. It was also proven at the test stand by testing a prototype stabilizer bar. Therefore, it was suggested to supplement the technological process with an additional shot peening operation whose main aim was to reduce the length of microcracks on the stabilizer bar’s surface. This effect was confirmed during comparative metallographic tests of not shot – peened and shot – peened stabilizer bars. After shot peening, the analysed stabilizer bar reached a fatigue strength which exceeded the limits set by the manufacturer.

  10. Effects of q and high beta on tokamak stability

    International Nuclear Information System (INIS)

    Brickhouse, N.S.; Callen, J.D.; Dexter, R.N.

    1984-08-01

    In the Columbia University Torus II tokamak plasmas have been studied with volume averaged toroidal beta values as high as 15%. Experimental equilibria have been compared with a 2D free boundary MHD equilibrium code PSEC. The stability of these equilibria has been computed using PEST, the predictions of which are compatible with an observed instability in Torus II which may be characterized as a high toroidal mode number ballooning fluctuation. In the University of Wisconsin Tokapole II tokamak disruptive instability behavior is investigated, with plasma able to be confined on closed magnetic surfaces in the scrape-off region, as the cylindrical edge safety factor is varied from q approx. 3 to q approx. 0.5. It is observed that at q/sub a/ approx. 3 major disruption activity occurs without current terminations, at q/sub a/ less than or equal to 2 well-confined plasmas are obtained without major disruption, and at q/sub a/ approx. 0.5 only partial reconnection accompanies minor disruptions

  11. Quantization Effects and Stabilization of the Fast-Kalman Algorithm

    Directory of Open Access Journals (Sweden)

    Constantin Papaodysseus

    2001-10-01

    Full Text Available The exact and actual cause of the failure of the fast-Kalman algorithm due to the generation and propagation of finite-precision or quantization error is presented. It is demonstrated that out of all the formulas that constitute this fast Recursive Least Squares (RLS scheme only three generate an amount of finite-precision error that consistently propagates in the subsequent iterations and eventually makes the algorithm fail after a certain number of recursions. Moreover, it is shown that there is a very limited number of specific formulas that transmit the generated finite-precision error, while there is another class of formulas that lift or “relax” this error. In addition, a number of general propositions is presented that allow for the calculation of the exact number of erroneous digits with which the various quantities of the fast-Kalman scheme are computed, including the filter coefficients. On the basis of the previous analysis a method of stabilization of the fast-Kalman algorithm is developed and is presented here, a method that allows for the fast-Kalman algorithm to follow very difficult signals such as music, speech, environmental noise, and other nonstationary ones. Finally, a general methodology is pointed out, that allows for the development of new algorithms which, intrinsically, suffer far less of finite-precision problems.

  12. The effect of wood extractives on the thermal stability of different wood species

    Energy Technology Data Exchange (ETDEWEB)

    Shebani, A.N.; Reenen, A.J. van [Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, Matieland 7602 (South Africa); Meincken, M. [Department of Forest and Wood Science, University of Stellenbosch, Private Bag X1, Matieland 7602 (South Africa)], E-mail: mmein@sun.ac.za

    2008-05-30

    This study compares the thermal stability of different wood species, which is an important factor for the production of wood-polymer composites (WPCs), and investigates the effect of extraction on thermal properties. The chemical composition of four wood species -Quercus alba, Pinus radiata, Eucalyptus grandis and Acacia cyclops - has been determined, as the species is expected to affect the thermal stability of wood. Subsequently, the hot-water (HW) extractives, ethanol/cyclohexane (E/C) extractives and both extractives were eliminated from the wood via Soxhlet extraction and the thermal stability of the wood determined with thermogravimetric analysis (TGA) under identical conditions. The results suggest that a higher cellulose and lignin content leads to better thermal stability of wood in different temperature regimes. In all cases, the removal of extractives improved the thermal stability of the wood. The effect of combined extractions was more pronounced than of an individual extraction and E/C-extraction caused less improvement in the thermal stability of wood than HW extraction. The degradation of the investigated wood extractives occurred at low rates over a broad temperature range. Pure cellulose exhibited superior thermal stability compared to wood, but differences were observed between the investigated wood species.

  13. Effect of buffer systems and disaccharides concentration on Podoviridae coliphage stability during freeze drying and storage.

    Science.gov (United States)

    Dini, C; de Urraza, P J

    2013-06-01

    The aims of this study were to determine the stability of Podoviridae coliphage CA933P during lyophilization and storage in different media, and to establish similarities between the results obtained and those expected through mechanisms described for proteins stabilization during freeze-drying. PBS and SM buffer were assayed as lyophilization media. The effect of inorganic salts concentration as well as the addition of disaccharides on phage stability during freeze-drying and storage was also studied. The addition of low sucrose concentration (0.1 mol l⁻¹) to SM buffer stabilized phage during freezing and drying steps of the lyophilization process, but higher sugar concentrations were detrimental to phage stability during freeze-drying. Sucrose stabilized phage during storage for at least 120 days. The lyoprotective effect of low concentrations of disaccharides during the drying step of the lyophilization of proteins as well as the stabilization of the freeze-dried product in time correlated with the results obtained for phage CA933P. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Chemical stabilization of baiji sand dunes in iraq 1. Effect of some soil stabilizers on the infiltration rate of sand

    OpenAIRE

    Ahmed, Naif B. [نايف بكر احمد

    1995-01-01

    In this study, the effect of soil chemical stabilizers including polyvinyl alcohol 125,000 (PVA) (0.2% and 0.4%); ferquatac resin emulsion RB-50 (F.E.) (0.14, 0.18, 0.2 and 0.4 lm'2); bitumen emulsion Al-55 (B.E.) (0.3, 0.4, 0.5 and 1.0 lm"2); aquapol resin 35-0019 (Aql) (0.33% and 0.66%) and aquapol resin 35-0031 (Aq2) (150, 175, 200 and 250 gm m ) on the infiltration rate of Baiji dunes sand was investigated. The results indicated that, both PVA concentrations increased the infiltration rat...

  15. Effect of virtual mass on the characteristics and the numerical stability in two-phase flows

    International Nuclear Information System (INIS)

    No, H.C.; Kazimi, M.S.

    1981-04-01

    It is known that the typical six equation two-fluid model of the two-phase flow possesses complex characteristics, exhibits unbounded instabilities in the short-wavelength limit and constitutes an ill-posed initial value problem. Among the suggestions to overcome these difficulties, one model for the virtual mass force terms were studied here, because the virtual mass represents real physical effects to accomplish the dissipation for numerical stability. It was found that the virtual mass has a profound effect upon the mathematical characteristic and numerical stability. Here a quantitative bound on the coefficient of the virtual mass terms was suggested for mathematical hyperbolicity and numerical stability. It was concluded that the finite difference scheme with the virtual mass model is restricted only by the convective stability conditions with the above suggested value

  16. Effective stability around the Cassini state in the spin-orbit problem

    Science.gov (United States)

    Sansottera, Marco; Lhotka, Christoph; Lemaître, Anne

    2014-05-01

    We investigate the long-time stability in the neighborhood of the Cassini state in the conservative spin-orbit problem. Starting with an expansion of the Hamiltonian in the canonical Andoyer-Delaunay variables, we construct a high-order Birkhoff normal form and give an estimate of the effective stability time in the Nekhoroshev sense. By extensively using algebraic manipulations on a computer, we explicitly apply our method to the rotation of Titan. We obtain physical bounds of Titan's latitudinal and longitudinal librations, finding a stability time greatly exceeding the estimated age of the Universe. In addition, we study the dependence of the effective stability time on three relevant physical parameters: the orbital inclination, , the mean precession of the ascending node of Titan orbit, , and the polar moment of inertia,.

  17. The stabilizing effect of streaks on Tollmien-Schlichting and oblique waves: A parametric study

    Science.gov (United States)

    Bagheri, Shervin; Hanifi, Ardeshir

    2007-07-01

    The stabilizing effect of finite amplitude streaks on the linear growth of unstable perturbations [Tollmien-Schlichting (TS) and oblique waves] is numerically investigated by means of the nonlinear parabolized stability equations. We have found that for stabilization of a TS-wave, there exists an "optimal" spanwise spacing of the streaks. These streaks reach their maximum amplitudes close to the first neutral point of the TS-wave and induce the largest distortion of the mean flow in the unstable region of the TS-wave. For such a distribution, the required streak amplitude for complete stabilization of a given TS-wave is considerably lower than for β =0.45, which is the optimal for streak growth and used in previous studies. We have also observed a damping effect of streaks on the growth rate of oblique waves in Blasius boundary layer and for TS-waves in Falkner-Skan boundary layers.

  18. Effect of thermal aging on stability of transformer oil based temperature sensitive magnetic fluids

    Science.gov (United States)

    Kaur, Navjot; Chudasama, Bhupendra

    2018-04-01

    Synthesizing stable temperature sensitive magnetic fluids with tunable magnetic properties that can be used as coolant in transformers is of great interest, however not exploited commercially due to the lack of its stability at elevated temperatures in bulk quantities. The task is quite challenging as the performance parameters of magnetic fluids are strongly influenced by thermal aging. In this article, we report the effect of thermal aging on colloidal stability and magnetic properties of Mn1-xZnxFe2O4 magnetic fluids prepared in industrial grade transformer oil. As-synthesized magnetic fluids possess good dispersion stability and tunable magnetic properties. Effect of accelerated thermal aging on the dispersion stability and magnetic properties have been evaluated by photon correlation spectroscopy and vibration sample magnetometry, respectively. Magnetic fluids are stable under accelerated aging at elevated temperatures (from 50 °C to 125 °C), which is critical for their efficient performance in high power transformers.

  19. The effect of effective microorganisms (EM on EBPR in modified contact stabilization system

    Directory of Open Access Journals (Sweden)

    Ehab M. Rashed

    2015-12-01

    Full Text Available Excessive phosphorus can cause eutrophication in water bodies and needs to be reduced in most wastewaters before discharge to receiving waters. The enhanced biological phosphorus removal (EBPR process has been shown to be an economical and environmentally compatible method for reducing phosphorus from wastewaters. The experiment has been performed in order to investigate the effect of using effective microorganisms (EM as an application of Enhanced Biological Phosphorous Removal (EBPR in modified contact stabilization activated sludge system by using contact tank as a phosphorus uptake zone and using thickener tank as a phosphorus release zone. The study involved the construction of a pilot plant which was setup in the Quhafa Wastewater Treatment Plant (WWTP, Al Fayoum, Egypt. Then the uptake and release of total phosphorus were determined through two batch tests using sludge samples from thickener and stabilization tanks. Results showed the removal efficiencies of Chemical Oxygen Demand (COD, Biological Oxygen Demand (BOD5 and total phosphorus (TP of this pilot plant were 93%, 93% and 90%, respectively. On the other hand the results of batch tests showed that the reason for high ability of phosphorus removal by this pilot plant is related to the high performance of microorganisms for phosphorus accumulation. Finally providing activated EM to the anaerobic zone was to improve fermentation by achieving the enhancement of the performance of phosphorus accumulating organisms (PAOs and then increase phosphorous release resulting in the decrease of the average effluent phosphorus concentration.

  20. On the stability analysis of a general discrete-time population model involving predation and Allee effects

    International Nuclear Information System (INIS)

    Merdan, H.; Duman, O.

    2009-01-01

    This paper presents the stability analysis of equilibrium points of a general discrete-time population dynamics involving predation with and without Allee effects which occur at low population density. The mathematical analysis and numerical simulations show that the Allee effect has a stabilizing role on the local stability of the positive equilibrium points of this model.

  1. Effect of natural antioxidants on the stability of ostrich meat during storage

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Arab, E. A.; Abu-Salem, F. M.

    2010-07-01

    Meat from the ostrich is becoming increasingly popular throughout the world. The aim of the current study was to evaluate the effects of different antioxidants such as ascorbic acid (AA), {alpha}-tocopherol (Toc) and rosemary herb (Ros) on the stability of ostrich meat during storage. The chemical composition of ostrich meat showed low fat content (1.5 %) combined with high protein content (22.4 %). The combination of AA Ros, Toc Ros and AA Toc was more effective in reducing the thiobarbituric acid (TBA) and peroxide values. The antioxidant showed insignificant effects on acidity as oleic acid. The addition of the efficient role of AA, Toc and Ros showed an improvement in the color stability of ostrich steaks and the combined treatment was more effective in color stability. In conclusion, the addition of AA, Toc and Ros had a positive effect on aroma quality, rancidity and discoloration of refrigerated ostrich meat. (Author) 41 refs.

  2. The Effect of Wearing Different Types of Respirators on Postural Stability and Comfort

    OpenAIRE

    Farhang Akbar-Khanzadeh; Sandra M. Woolley; Kent Huang

    2012-01-01

    Respirators are commonly used to protect workers against workplace airborne contaminants, but this equipment may become a safety hazard by creating discomfort, disorientation and postural instability.Although postural stability is critical to workers, especially those working near moving objects or on surfaces where a loss of balance may become life threatening, little attention has been given to the effect of respirators on wearers’ postural stability. The purpose of this study was to examin...

  3. Effect of tune modulation on the transverse stability of storage ring

    International Nuclear Information System (INIS)

    Yang Jiancheng; Xia Jiawen; Wu Junxia; Xia Guoxing; Liu Wei; Yin Xuejun; Liu Yong; Zhou Xuemei; Mao Lijun

    2004-01-01

    The transverse stability is a critical issue in circular accelerator. In this paper, authors analysed the effect of tune modulation on a FODO lattice with sextupole nonlinear through estimating the dynamic aperture including the influence of the distortion along the phase. It turned out that the tune modulation decreases the stability of particle in storage ring, the extent of this decrease depends largely on the amplitude and tune of modulation. (author)

  4. Effect of repeated immersion solution cycles on the color stability of denture tooth acrylic resins

    OpenAIRE

    Paulo Maurício Batista da Silva; Emílio José Tabaré Rodríguez Acosta; Matheus Jacobina; Luciana de Rezende Pinto; Vinícius Carvalho Porto

    2011-01-01

    OBJECTIVE: Chemical solutions have been widely used for disinfection of dentures, but their effect on color stability of denture tooth acrylic resins after repeated procedures is still unclear. The aim of this in vitro study was to evaluate whether repeated cycles of chemical disinfectants affected the color stability of two denture tooth acrylic resins. MATERIAL AND METHODS: Sixty disc-shaped specimens (40 mm x 3 mm) were fabricated from two different brands (Artiplus and Trilux) of denture ...

  5. Effect of Nano-Scale Roughness on Particle Wetting and on Particle-Mediated Emulsion Stability

    Science.gov (United States)

    San Miguel, Adriana; Behrens, Sven

    2012-02-01

    Colloidal particles can strongly adsorb to liquid interfaces and stabilize emulsions against droplet coalescence, the effectiveness of which depends crucially on the particle wettability. From the study of macroscopic solids, surface wetting is known to be influenced strongly by nano-scale roughness (as seen e.g. in the ``Lotus effect'' or in anti-fog coatings); similarly, strong effects of particle roughness on particle-stabilized emulsions should be expected. Here we report the first experimental study of particle wetting and particle-mediated emulsion stability in which particle roughness could be varied continuously without varying the surface chemistry. We demonstrate an enabling method for preparing particles and macroscopic substrates with tunable nano-roughness and correlate the extent of roughness quantitatively with surface wetting (measured via the three-phase contact angle) and with emulsion stability (quantifiable via the maximum capillary pressure). Our results confirm a dramatic influence of roughness on wetting, emulsion stability, and even the type of emulsion formed (o/w vs. w/o) upon mixing oil with an aqueous particle dispersion. Whether particle roughness benefits emulsion stability or not is seen to depend on both the size and shape of the surface features.

  6. Solvation effect on isomer stability and electronic structures of protonated serotonin

    Science.gov (United States)

    Omidyan, Reza; Amanollahi, Zohreh; Azimi, Gholamhassan

    2017-07-01

    Microsolvation effect on geometry and transition energies of protonated serotonin has been investigated by MP2 and CC2 quantum chemical methods. Also, conductor-like screening model, implemented recently in the MP2 and ADC(2) methods, was examined to address the bulk water environment's effect on the isomer stability and electronic transition energies of protonated serotonin. It has been predicted that the dipole moment of gas phase isomers plays the main role on the isomer stabilization in water solution and electronic transition shifts. Also, both red- and blue-shift effects have been predicted to take place on electronic transition energies, upon hydration.

  7. Stability analysis of sandy slope considering anisotropy effect in ...

    Indian Academy of Sciences (India)

    Studying the role of anisotropy in response to geotechnical structure requires the constitutive model which comprehensively accounts the effect of anisotropy on the mechanical behavior of soil. Casagrande & Carillo (1944) have presented a closed-form equation for relating between the soil cohesion in Mohr–Columb ...

  8. Evaluation of the simultaneous effects of a heat stabilized starter ...

    African Journals Online (AJOL)

    This study evaluates the simultaneous effect of dried starter concentration and fermentation duration on the quality characteristics of the African opaque sorghum beer using response surface methodology. The aim was to improve the beer quality and to optimize its fermentation process. Results show that the granule starter ...

  9. Effects of heat treatment on density, dimensional stability and color ...

    African Journals Online (AJOL)

    The purpose of this study was to evaluate the effect of heat treatment on some physical properties and color change of Pinus nigra wood which has high industrial use potential and large growing stocks in Turkey. Wood samples which comprised the material of the study were obtained from an industrial plant. Samples were ...

  10. Effect of Moringa oleifera marinade on microbial stability of smoke ...

    African Journals Online (AJOL)

    The study examined the antimicrobial effect of Moringa oleifera marinade on smoke-dried catfish stored at ambient temperature (37±20C) for two months. The experimental treatments are the control, 1%, 2% and 3% (w/v) Moringa oleifera Marinade (MOM) and 5% Brine (w/v) solutions. Seventy-five fishes of average weight ...

  11. Effects of vasodilator and esmolol-induced hemodynamic stability on ...

    African Journals Online (AJOL)

    Objective: To investigate the effect of continuous intravenous injection of nicardipine and/or nitroglycerin with or without esmolol on the occurrence of early post-operative cognitive dysfunction (POCD) in elderly patients. Methods: Elderly patients (n=340) who underwent radiofrequency ablation for atrial fibrillation were ...

  12. Effect of Surfactants on Plasmid DNA Stability and Release from ...

    African Journals Online (AJOL)

    Purpose: To evaluate the effect of surfactants on plasmid DNA during preparation and release from polylactic glycolide (PLGA) microspheres. Methods: Various surfactants, both ionic and non-ionic (Span, Tween, Triton X100, cetyltrimethylammonium bromide and sodium dodecyl sulphate), were added during the ...

  13. Reproducibility and stability of C60 based organic field effect transistor

    Science.gov (United States)

    Ahmed, Rizwan; Sams, Michael; Simbrunner, Clemens; Ullah, Mujeeb; Rehman, Kamila; Schwabegger, Günther; Sitter, H.; Ostermann, Timm

    2012-01-01

    A comprehensive study concerning the reproducibility and stability of organic n-type field effect transistors is presented. C60 based OFETs were chosen to investigate the fabrication reproducibility and the long term stability because C60 is a high mobility n-type material. We fabricated 48 transistors and each transistor was measured for 24 h inside the glove box. To test for life time stability – long term measurements up to three months have been undertaken. We report about the fluctuations in the device parameters of all investigated transistors by comparing the transfer characteristics, and on/off ratio for short time and long time measurements. C60 based OFETs showed good reproducibility and stability for short time measurements and a decay for long time measurements. PMID:22368321

  14. Effects of inserted depth of wall penetration on basal stability of foundation pits

    Science.gov (United States)

    Zhou, Aizhao; Shen, Hao; Sun, Jinguo

    2017-05-01

    Evaluation of basal heave stability is one of important design checks for excavations in soft clays. The commonly used classical calculation method based on limit equilibrium theory and the safety coefficient formula recommended by the current code, do not consider the influence of supporting structure of foundation pit depth heave stability, which results in conservative. Considering the wall stiffness and strength, the effective stress changes in different depth of soil, the frictional resistance between the retaining wall and the passive zone, the vertical shear resistance of the soil behind the wall and other factors. The modified safety factor calculation formula of foundation pit stability is presented, comparison analysis of calculation method combined with examples. The calculation results show that the safety factor of foundation pit stability is improved considering the influence of supporting structure depth, the calculation results are more reasonable.

  15. The Effects of Matched Filter on Stable Performance of Semistrapdown Inertially Stabilized Platform

    Directory of Open Access Journals (Sweden)

    Feng Liu

    2016-01-01

    Full Text Available To enhance the optimization performance of matched filter and further improve line of sight (LOS stability of platform in inertial space, the proposed matched filter algorithm is conducted by adjusting matched filter coefficients of first-order low pass filter utilizing the regional search method based on invariance principle. The coefficients of the fraction molecule and denominator of proposed regional search algorithm are altered instead of denominator coefficients only being modified. Simulations are performed to verify the validity of inside factors performed with stabilization control model and quartz rate sensor (QRS mathematical model. The stable angular error is sharply alleviated, so the decoupling accuracy of airborne semistrapdown inertially stabilized platform is largely promoted. The optimization matched filter can effectively increase stability of LOS in inertial space.

  16. The effect of gamma irradiation on the stability of cemented Winfrith reactor (SGHWR) sludge

    International Nuclear Information System (INIS)

    Holland, T.R.

    1985-01-01

    The effects of prolonged self-irradiation within cemented Winfrith SGHWR sludge have been investigated by exposing simulant material to a CO-60 source. Measurements of dimensional stability and radiolysis have been used in this assessment of radiation stability. The dimensional stability of the cement matrix was unaffected by an irradiation intensity which greatly exceeded the expected lifetime dose, and radiolysis rates have followed those which have previously been observed by other researchers. Data obtained for the release of radiolytic hydrogen has allowed a prediction to be made of release from the full-size product, during decay of the principal radioactive species, Co-60. A method has been developed for the determination of dimensional stability using non-standard sized specimens and is appended. (author)

  17. Testing the effect of a microbial-based soil amendment on aggregate stability and erodibility

    DEFF Research Database (Denmark)

    Malozo, Mponda; Iversen, Bo Vangsø; Heckrath, Goswin Johann

    Minimizing soil erosion is essential for maintaining proper soil quality and thus preserving soil productivity. The erodibility of a soil is closely linked to its structural stability as well as its infiltrability. This study focuses on testing the effect of two different soil amendments on soil...... aggregate stability and erodibility. Two commercial products, gypsum and a microbial-based solution were used for the experiment and were tested on two Danish sandy loamy soils as well on a sandy soil from Tanzania. The carrier of the microbial-based product, a glycerol solution, was tested as well....... In the laboratory, soils were treated with the soil amendments in a two-step procedure at controlled water contents following aerobic incubation in closed containers. Water-aggregate stability and clay dispersion were measured on soil aggregates less than 8 mm in diameter. Aggregate stability was measured...

  18. [Effects of loess soil stabilization on Lolium perenne L. growth and root activity].

    Science.gov (United States)

    Liu, Yue-mei; Zhang, Xing-chang; Wang, Dan-dan

    2011-10-01

    Taking the loess soils with bulk density 1.2 g cm(-3), 1.3 g cm(-3), and 1.4 g cm(-3) from Ansai, Shaanxi Province as test objects, a pot experiment was conducted to study the effects of different amendment amount of soil stabilizer (EN-1 stabilizer) on the growth and root activity of ryegrass (Lolium perenne L.). Within the range of the bulk densities, the leaf chlorophyll content, root activity, root/shoot ratio, root biomass, and plant biomass of L. perenne all decreased with increasing soil bulk density, and were higher under the amendment of EN-1 stabilizer, as compared with the control. With increasing amendment amount of EN-1 stabilizer, the leaf chlorophyll content, root activity, root/shoot ratio, root biomass, and plant biomass had a trend of increased first and decreased then. Soil bulk density and stabilizer amendment amount had significant interactive effect on the root biomass and plant biomass. Overall, the values of the test indices were the highest under 1.3 g cm(-3) soil bulk density and 0.15% EN-1 stabilizer amendment amount.

  19. The effect of leg preference on postural stability in healthy athletes.

    Science.gov (United States)

    Huurnink, Arnold; Fransz, Duncan P; Kingma, Idsart; Hupperets, Maarten D W; van Dieën, Jaap H

    2014-01-03

    In research regarding postural stability, leg preference is often tested and controlled for. However, leg preference may vary between tasks. As athletes are a group of interest for postural stability testing, we evaluated the effect of five leg preference tasks categorization (step up, hop, ball kick, balance, pick up) on single-leg postural stability of 16 field hockey athletes. The 'center of pressure speed' was calculated as the primary outcome variable of single-leg postural stability. Secondary variables were 'mean length of the GRF vector in the horizontal plane', 'mean length of the ankle angular velocity vector', and 'mean length of the hip angular velocity vector', as well as the separate outcomes per degree of freedom. Results showed that leg preference was inconsistent between leg preference tasks. Moreover, the primary and secondary variables yielded no significant difference between the preferred and non-preferred legs, regardless of the applied leg preference task categorization (p>0.05). The present findings do not support the usability of leg preference tasks in controlling for bias of postural stability. In conclusion, none of the applied leg preference tasks revealed a significant effect on postural stability in healthy field hockey athletes. © 2013 Published by Elsevier Ltd.

  20. Effect of speed on local dynamic stability of locomotion under different task constraints in running.

    Science.gov (United States)

    Mehdizadeh, Sina; Arshi, Ahmed Reza; Davids, Keith

    2014-01-01

    A number of studies have investigated effects of speed on local dynamic stability of walking, although this relationship has been rarely investigated under changing task constraints, such as during forward and backward running. To rectify this gap in the literature, the aim of this study was to investigate the effect of running speed on local dynamic stability of forward and backward running on a treadmill. Fifteen healthy male participants took part in this study. Participants ran in forward and backward directions at speeds of 80%, 100% and 120% of their preferred running speed. The three-dimensional motion of a C7 marker was recorded using a motion capture system. Local dynamic stability of the marker was quantified using short- and long-term largest finite-time Lyapunov exponents (LyE). Results showed that short-term largest finite-time LyE values increased with participant speed meaning that local dynamic stability decreased with increasing speed. Long-term largest finite-time LyEs, however, remained unaffected as speed increased. Results of this study indicated that, as in walking, slow running is more stable than fast running. These findings improve understanding of how stability is regulated when constraints on the speed of movements is altered. Implications for the design of rehabilitation or sport practice programmes suggest how task constraints could be manipulated to facilitate adaptations in locomotion stability during athletic training.

  1. Effectiveness of electronic stability control on single-vehicle accidents

    DEFF Research Database (Denmark)

    Lyckegaard, Allan; Hels, Tove; Bernhoft, Inger Marie

    2015-01-01

    the following were significant. For the driver: Age, gender, driving experience, valid driving license, and seat belt use. For the vehicle: Year of registration, weight, and ESC. For the accident surroundings: Visibility, light, and location. Finally, for the road: Speed limit, surface, and section...... manufactured in the period 1998 to 2011 and the principle of induced exposure, 2 measures of the effectiveness of ESC were calculated: The crude odds ratio and the adjusted odds ratio, the latter by means of logistic regression. The logistic regression controlled for a number of confounding factors, of which...... characteristics. Results: The present study calculated the crude odds ratio for ESC-equipped cars of getting in a single-vehicle injury accident as 0.40 (95% confidence interval [CI], 0.34-0.47) and the adjusted odds ratio as 0.69 (95% CI, 0.54-0.88). No difference was found in the effectiveness of ESC across...

  2. Flow shear stabilization of rotating plasmas due to the Coriolis effect

    NARCIS (Netherlands)

    Haverkort, J. W.; de Blank, H. J.

    2012-01-01

    A radially decreasing toroidal rotation frequency can have a stabilizing effect on nonaxisymmetric magnetohydrodynamic (MHD) instabilities. We show that this is a consequence of the Coriolis effect that induces a restoring pressure gradient force when plasma is perturbed radially. In a rotating

  3. Flow shear stabilization of rotating plasmas due to the Coriolis effect

    NARCIS (Netherlands)

    J.W. Haverkort (Willem); H.J. de Blank

    2012-01-01

    htmlabstractA radially decreasing toroidal rotation frequency can have a stabilizing effect on nonaxisymmetric magnetohydrodynamic (MHD) instabilities. We show that this is a consequence of the Coriolis effect that induces a restoring pressure gradient force when plasma is perturbed radially. In a

  4. The effects of public perception of Yar'adua's leadership on stability ...

    African Journals Online (AJOL)

    This work is an attempt to use the factors of legitimacy, political will, charisma, political culture, popular participation, political stability and social integration; identified by the respondents as the highpoints for determining the effectiveness and efficiency of the president, to assess the effectiveness and efficiency of President ...

  5. Effect of cooling water on stability of NLC linac components

    Energy Technology Data Exchange (ETDEWEB)

    F. Le Pimpec et al.

    2003-02-11

    Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.

  6. Effect of Cooling Water on Stability of NLC Linac Components

    Energy Technology Data Exchange (ETDEWEB)

    Le Pimpec, Frederic

    2002-11-01

    Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.

  7. Effects of noxious stimulation to the back or calf muscles on gait stability.

    Science.gov (United States)

    van den Hoorn, Wolbert; Hug, François; Hodges, Paul W; Bruijn, Sjoerd M; van Dieën, Jaap H

    2015-11-26

    Gait stability is the ability to deal with small perturbations that naturally occur during walking. Changes in motor control caused by pain could affect this ability. This study investigated whether nociceptive stimulation (hypertonic saline injection) in a low back (LBP) or calf (CalfP) muscle affects gait stability. Sixteen participants walked on a treadmill at 0.94ms(-1) and 1.67ms(-1), while thorax kinematics were recorded using 3D-motion capture. From 110 strides, stability (local divergence exponent, LDE), stride-to-stride variability and root mean squares (RMS) of thorax linear velocities were calculated along the three movement axes. At 0.94ms(-1), independent of movement axes, gait stability was lower (higher LDE) and stride-to-stride variability was higher, during LBP and CalfP than no pain. This was more pronounced during CalfP, likely explained by the biomechanical function of calf muscles in gait, as supported by greater mediolateral RMS and stance time asymmetry than in LBP and no pain. At 1.67ms(-1), independent of movement axes, gait stability was greater and stride-to-stride variability was smaller with LBP than no pain and CalfP, whereas CalfP was not different from no pain. Opposite effects of LBP on gait stability between speeds suggests a more protective strategy at the faster speed. Although mediolateral RMS was greater and participants had more asymmetric stance times with CalfP than LBP and no pain, limited effect of CalfP at the faster speed could relate to greater kinematic constraints and smaller effects of calf muscle activity on propulsion at this speed. In conclusion, pain effects on gait stability depend on pain location and walking speed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Effect of Magnetic Shear and Plasma Compressibility on Ideal Interchange Mode Stability

    Science.gov (United States)

    Mirnov, V. V.; Hegna, C. C.

    2003-10-01

    We analyze the stability of a localized ideal interchange mode in a cylindrical screw pinch equilibrium. In the general case, the screw pinch magnetic configuration has magnetic shear. From the Energy Principle, it follows that the most dangerous interchange perturbations, k_||=0, are incompressible, and marginal stability is given by Suydam's criterion. In the particular case of a screw pinch without axial field (Z-pinch), the magnetic configuration is shear free and, correspondingly, the stabilizing effect of shear vanishes. In this case, the magnetic field is pure poloidal, and the resonance condition of interchange modes, k_||=0, corresponds to m=0 "sausage"-like perturbations. For these modes, the effect of plasma compressibility becomes important and, in some sense, it replaces the stabilizing effect of magnetic shear. We investigate the transition between these two stabilizing mechanisms as the equilibrium changes from one with magnetic shear to a magnetic shear free configuration. This is of interest for closed systems with rational surfaces where dq/dr arrow 0 as well as for non paraxial open traps and magnetic dipoles where the effect of plasma compression plays important role.

  9. Effect of hydroxypropyl-β-cyclodextrin on the stability of cisapride in oral suspensions

    Directory of Open Access Journals (Sweden)

    Jutima Boonleang

    2010-12-01

    Full Text Available Cisapride (CIS is a gastrointestinal prokinetic agent. It has been associated with rare, but serious cardiac side effects.However, it does not affect psychomotor functions or induce central depressant adverse effects. As liquid formulations arerequired in a number of cases, an oral suspension of CIS was developed from CIS tablets. The objective of this study was toinvestigate the effect of hydroxypropyl--cyclodextrin (HP--CD on the stability of CIS in oral suspension with an ultimateaim to formulate a more stable CIS oral suspension. Six batches of CIS oral suspensions, namely, 0 (control, 0.3, 1.6, and 3%HP--CD containing formulations were prepared. They were stored at 5°C and 30°C. The amounts of CIS in the suspensionswere determined by a validated stability-indicating HPLC-DAD method. The stability was assessed based on the 90%remaining. The changes in the amounts of CIS over time were statistically analyzed by ANOVA and ANCOVA. At 5°C, HP--CD had no significant effect on the stability of CIS. CIS in all four formulations was stable for at least 12.5 months. At 30°C,HP--CD affected the stability of CIS. CIS was most stable in 0.3% HP--CD containing formulation with the observed t90 ofapproximately 11 months as compared to 7 months in control formulation.

  10. Effect of Core Stability Training on Trunk Function, Standing Balance, and Mobility in Stroke Patients.

    Science.gov (United States)

    Haruyama, Koshiro; Kawakami, Michiyuki; Otsuka, Tomoyoshi

    2017-03-01

    Trunk function is important for standing balance, mobility, and functional outcome after stroke, but few studies have evaluated the effects of exercises aimed at improving core stability in stroke patients. To investigate the effectiveness of core stability training on trunk function, standing balance, and mobility in stroke patients. An assessor-blinded, randomized controlled trial was undertaken in a stroke rehabilitation ward, with 32 participants randomly assigned to an experimental group or a control group (n = 16 each). The experimental group received 400 minutes of core stability training in place of conventional programs within total training time, while the control group received only conventional programs. Primary outcome measures were evaluated using the Trunk Impairment Scale (TIS), which reflects trunk function. Secondary outcome measures were evaluated by pelvic tilt active range of motion in the sagittal plane, the Balance Evaluation Systems Test-brief version (Brief-BESTest), Functional Reach test, Timed Up-and-Go test (TUG), and Functional Ambulation Categories (FAC). A general linear repeated-measures model was used to analyze the results. A treatment effect was found for the experimental group on the dynamic balance subscale and total score of the TIS ( P = .002 and P Core stability training has beneficial effects on trunk function, standing balance, and mobility in stroke patients. Our findings might provide support for introducing core stability training in stroke rehabilitation.

  11. Climatic effects of nuclear war: The role of atmospheric stability and ground heat fluxes

    International Nuclear Information System (INIS)

    Mitchell, J.F.B.; Slingo, A.

    1988-01-01

    Most studies of the climatic effects of nuclear war have used atmospheric models with simple representations of important physical processes. In this work, a model is used which treats the diurnal cycle of insolation, and includes surface and boundary layer parameterizations which take into account static stability and a four-layer soil model. Three idealized experiments are described in which a band of smoke is prescribed over northern mid-latitudes in In the experiment, the standard model is used, in the second the effect of deep soil layers is ignored and in the third the stability dependence in the surface and boundary layer processes is removed. It is found that the inclusion of deep soil layers decreases the surface cooling by about 20%, whereas the inclusion of stability effects increases the cooling by about the same amount, though conclusions will depend to some extent on the model used. copyright American Geophysical Union 1988

  12. Pressure effects on catalytic properties and structural stability of human paraoxonase

    Energy Technology Data Exchange (ETDEWEB)

    Clery-Barraud, C; Leva, J; Bakdouri, N E; Renault, F; Masson, P; Rochu, D [Departement de Toxicologie, Centre de Recherches du Service de Sante des Armees, BP 87, 38702 La Tronche cedex (France)], E-mail: cclerybarraud@crssa.net

    2008-07-15

    Human paraoxonase (HuPON1) is a candidate as catalytic bioscavenger for pre-treatment and therapy of poisoning by organophosphate compounds. HuPON1 is a hydrophobic protein associated with a partner, the human phosphate binding protein (HPBP) in plasma high density lipoproteins. The relationship between the composition and the size of multimeric states of HuPON1 is not well understood. Moreover the effect of HPBP's presence on enzyme catalytic mechanisms and stability is unclear. We investigated the effect of hydrostatic pressure and temperature on structural stability and activity of different PON1 preparations (hybrid recombinant PON1, natural HuPON1 free of its partner or in the presence of 50% w/w HPBP). We showed that PON1 exists under several multimeric forms and that the binding of HPBP amends the size of the hetero-oligomeric states and exerts a stabilizing effect on the activity of PON1.

  13. Pressure effects on catalytic properties and structural stability of human paraoxonase

    Science.gov (United States)

    Cléry-Barraud, C.; Leva, J.; Bakdouri, N. E.; Renault, F.; Masson, P.; Rochu, D.

    2008-07-01

    Human paraoxonase (HuPON1) is a candidate as catalytic bioscavenger for pre-treatment and therapy of poisoning by organophosphate compounds. HuPON1 is a hydrophobic protein associated with a partner, the human phosphate binding protein (HPBP) in plasma high density lipoproteins. The relationship between the composition and the size of multimeric states of HuPON1 is not well understood. Moreover the effect of HPBP's presence on enzyme catalytic mechanisms and stability is unclear. We investigated the effect of hydrostatic pressure and temperature on structural stability and activity of different PON1 preparations (hybrid recombinant PON1, natural HuPON1 free of its partner or in the presence of 50% w/w HPBP). We showed that PON1 exists under several multimeric forms and that the binding of HPBP amends the size of the hetero-oligomeric states and exerts a stabilizing effect on the activity of PON1.

  14. The Effects of Electroless Nickel Plating Bath Conditions on Stability of Solution and Properties of Deposit

    International Nuclear Information System (INIS)

    Huh, Jin; Lee, Jae Ho

    2000-01-01

    Electroless depositions of nickel were conducted in different bath conditions to find optimum conditions of electroless nickel plating at low operating temperature and pH. The effect of complexing reagent on stability of plating solution was investigated. Sodium citrate complexed plating solution is more stable than sodium pyrophosphate complexed solution. The effects of nickel salt concentration, reducing agent, complexing agent and inhibitor on deposition rate was investigated. The effects of pH on deposition rate and content of phosphorous in deposited nickel were also analyzed. Electroless deposited nickel become crystallized with increasing pH due to lower phosphorous content. In optimum operating bath condition, deposition rate was 7 μm/hr at 60 .deg. C and pH 10.0 without stabilizer. The rate was decreased with stabilizer concentration

  15. Preventive effects of stretching and stabilization exercises on muscle fatigue in mobile phone users.

    Science.gov (United States)

    Kim, Hye-Young; Yeun, Young-Ran; Kim, Sung-Joong

    2016-09-01

    [Purpose] The purpose of this study was to investigate the preventive effects of stretching and stabilization exercises on muscle fatigue of the neck erector spine and upper trapezius muscles. [Subjects and Methods] The subjects of this study were 26 healthy university students (14 males and 12 females). Each subject was assigned randomly to each of three study groups in order to prevent order effect. The three groups included in this study were the no-exercise, stretching exercise, and neck stabilization exercise groups. The median electromyographic frequency was used as a gauge of muscle fatigue. [Results] Decreased muscle fatigue was demonstrated by an increase in the median electromyographic frequency values in all the four muscle groups in the comparison between conditions 1 and 3. In particular, statistically significant differences were found between the two conditions in the right upper trapezius muscle group. [Conclusion] These findings suggest that the effect of stretching and stabilization exercises can reduce muscle fatigue in mobile phone users.

  16. Computing Stability Effects of Mutations in Human Superoxide Dismutase 1

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2014-01-01

    displayed less structural sensitivity, with the standard deviation from different high-resolution structures down to ∼0.2 kcal/mol. Structures of variable resolution and number of protein copies locally affected specific sites, emphasizing the use of state-relevant crystal structures when such sites...... are of interest, but had little impact on overall batch estimates. Protein-interaction effects (as a mimic of crystal packing) were small for the more accurate methods. Thus, batch computations, relevant to, e.g., comparisons of disease/nondisease mutant sets or different clades in phylogenetic trees, are much...... (glycine has a low structural propensity) or water colocalization with glycine....

  17. Changing circulation structure and precipitation characteristics in Asian monsoon regions: greenhouse warming vs. aerosol effects

    Science.gov (United States)

    Lau, William K. M.; Kim, Kyu-Myong; Ruby Leung, L.

    2017-12-01

    Using model outputs from CMIP5 historical integrations, we have investigated the relative roles of anthropogenic emissions of greenhouse gases (GHG) and aerosols in changing the characteristics of the large-scale circulation and rainfall in Asian summer monsoon (ASM) regions. Under GHG warming, a strong positive trend in low-level moist static energy (MSE) is found over ASM regions, associated with increasing large-scale land-sea thermal contrast from 1870s to present. During the same period, a mid-tropospheric convective barrier (MCB) due to widespread reduction in relative humidity in the mid- and lower troposphere is strengthening over the ASM regions, in conjunction with expanding areas of anomalous subsidence associated with the Deep Tropical Squeeze (Lau and Kim in Proc Natl Acad Sci 12:3630-3635, 2015). The opposing effects of MSE and MCB lead to enhanced total ASM rainfall, but only a partial strengthening of the southern portion of the monsoon meridional circulation, coupled to anomalous multi-cellular overturning motions over ASM land. Including anthropogenic aerosol emissions strongly masks MSE but enhances MCB via increased stability in the lower troposphere, resulting in an overall weakened ASM circulation with suppressed rainfall. Analyses of rainfall characteristics indicate that under GHG, overall precipitation efficiency over the ASM region is reduced, manifesting in less moderate but more extreme heavy rain events. Under combined effects of GHG and aerosols, precipitation efficiency is unchanged, with more moderate, but less extreme rainfall.

  18. Effect of external conditions on the stability of enzymically synthesized carthamin

    Directory of Open Access Journals (Sweden)

    Koshi Saito

    2014-01-01

    Full Text Available Enzymically synthesized carthamin was subjected to testing of its stability under various conditions. It easily turned to unknown reddish-yellow or orange-yellow substances in water. This instability was further accelerated by the presence of a sulfhydryl reagent and or at higher temperature. In a typical result, the rate of the discolouration was calculated to be 21 nmol carthamin h-1 at 20 °C in water and rose to 44.0 nmol carthamin h-1 at 60 °C in water containing 1.0 mM 2-mercaptoethanol. Organic solvents such as methanol, ethanol and acetone showed little effect on carthamin discolouration, while the stability of carthamin in these solvents was gradually decreased by rising temperature. In various buffers, in the acidic range. carthamin was relatively stable, whereas, it turned unstable on the basic side. All of the thiol reagents tested were unfavourable for retaining stability of carthamin in solutions. 2-Mercaptoethanol, reduced glutathione and thioglycollic acid exhibited the strongest degrading effect on the pigment. At the 1.0 mM level, 2-mercaptoethanol reduced the absorption peak at 517 nm by 0.02 min-1, which corresponded to 0.12 nmol carthamin cm-3 min-1 L-Methionine, L-ascorbic and D-araboascorbic acids were found to be strong bathochromic effectors For example, L-methionine rised AA 517 nm up to 0.01 min-1, whose value equaled to 0-1 nmol carthamin cm-3 min-1 at 30 °C Carthamin was absorbed and adsorbed and stabilized by many macro-molecular Substances. Among the compounds tested, cellulose was found to be the most effective stabilizer. The stabilization effect of cellulose was specific for carthamin and the term "SAITO EFFECT" is proposed for it. This effect was reduced by hydrolysis of the carthamin-adsorbed cellulose with Asperqillus cellulase in an incubation system

  19. Phenomenology and thermo-hydraulic stability of the CAREM-25 reactor: Evaluation of subcooled boiling effect

    International Nuclear Information System (INIS)

    Acuna, F.M.; Marcel, C.P.; Zanocco, P.G.; Delmastro, D.F.

    2012-01-01

    In this article the phenomenology present in self/pressurized, integral, natural circulation, low thermodynamic quality nuclear reactors similar to CAREM-25 is investigated. In particular, analytical relations for the mass flow rate, the core mean enthalpy and the location of the two phase boundary are derived in terms of the so-called natural variables of the system: the nuclear power, the condensation power and the system pressure. In addition, some consequences of the flashing phenomenon in the reactor thermal-hydraulics are discussed emphasizing those affecting the reactor stability. The reactor stability performance was studied by using the HUARPE code which is a low diffusive code. The stability results obtained by neglecting the subcooled effect in the system are presented in the so-called the stability maps in which the results are presented for a wide range of conditions. The stability effect caused by the presence of subcooled boiling in the reactor core was also examined. In order to investigate such a consequence, the code was slightly modified such that the predicted vapor profile in the hot leg is similar to that estimated by RELAP system code at steady state conditions. The simple implemented algorithm allows varying a free parameter with which a broad number of cases can be studied. This is important since the subcooled boiling predictions generally have large uncertainties and therefore to cover a large number of situations is desired to derive confident conclusions. The results show the existence of vapor created by means of subcooled boiling enhances the system stability for a wide range of conditions. For this reason from this preliminary investigation, it is concluded neglecting the subcooled effect in CAREM-25 stability studies is a conservative criterion (author))

  20. Effect of cariogenic challenge on the stability of dentin bonds

    Directory of Open Access Journals (Sweden)

    Fernanda Blos BORGES

    2014-01-01

    Full Text Available Objective: The oral environment is subject to biofilm accumulation and cariogenic challenge, and few studies exist on the effect of these factors on the bond strength of adhesive systems. The aim of this study was to test if the exposure of adhesive interfaces to cariogenic challenge under biofilm accumulation could promote higher degradation than the exposure to biofilm accumulation alone. Material And Methods: Five molars were ground until exposure of medium dentin and then restored (Single Bond 2 and Z250 3M ESPE. The tooth/resin sets were cut to obtain beam-shaped specimens, which were distributed according to the aging conditions (n=20: water for 24 h (control; biofilm under cariogenic challenge for 3, 5 or 10 days; biofilm without cariogenic challenge for 10 days; and water for 3 months. Microcosm biofilms were formed from human saliva and grown in a saliva analogue medium, supplemented or not with sucrose to promote cariogenic challenge. Specimens were tested for microtensile bond strength, and failure modes were classified using light microscopy. Bond strength data were analyzed using ANOVA and failure modes were analyzed using ANOVA on ranks (α=0.05. Results: No significant differences in bond strength were detected among the aging methods (P=0.248. The aging period was associated with an increase in the frequency of adhesive failures for the groups aged for 10 days or longer (P<0.001. Conclusion: Aging leads to a higher prevalence of interfacial adhesive failures, although this effect is not associated with cariogenic challenge or reduction in bond strengths.

  1. Hydrodynamic stability of thermoviscous liquid film inside a rotating horizontal cylinder: Heating and cooling effects

    Science.gov (United States)

    Kumawat, Tara Chand; Tiwari, Naveen

    2018-03-01

    Steady two-dimensional solutions and their stability analysis are presented for thin film of a thermoviscous liquid flowing inside a cylinder rotating about its horizontal axis. The inner surface of the cylinder is either uniformly hotter or colder than the enveloping air. The mass, momentum, and energy equations are simplified using thin-film approximation. The analytically obtained film thickness evolution equation consists of various dimensionless parameters such as gravitational number, Bond number, Biot number, thermoviscosity number, and Marangoni number. The viscosity of the liquid is considered as an exponential function of temperature. The viscosity increases (decreases) within the film thickness away from the inner surface of the cylinder when the surface is uniformly hotter (colder) than the atmosphere. For hotter (colder) surface, the film thickness on the rising side decreases (increases) when convective heat transfer at the free surface is increased. The surface tension gradient at the free surface generates Marangoni stress that has a destabilizing (stabilizing) effect on the thin film flow in the case of a hotter (colder) cylinder. The thermoviscosity number stabilizes (destabilizes) the flow on a heating (cooling) surface and this effect increases with an increase in the heat transfer at the free surface. For a hotter surface and in the presence of Marangoni stress, the convective heat transfer at the interface has the destabilizing effect for small values of the Biot number and assumes a stabilizing role for larger values. Non-linear simulations show consistency with the linear stability analysis.

  2. Effects of stabilizers on the heat transfer characteristics of a nuclear waste canister

    International Nuclear Information System (INIS)

    Vafai, K.; Ettefagh, J.

    1986-07-01

    This report summarizes the feasibility and the effectiveness of using stabilizers (internal metal structural components) to augment the heat transfer characteristics of a nuclear waste canister. The problem was modeled as a transient two-dimensional heat transfer in two physical domains - the stabilizer and the wedge (a 30-degree-angle canister segment), which includes the heat-producing spent-fuel rods. This problem is solved by a simultaneous and interrelated numerical investigation of the two domains in cartesian and polar coordinate systems. The numerical investigations were performed for three cases. In the first case, conduction was assumed to be the dominant mechanism for heat transfer. The second case assumed that radiation was the dominant mechanism, and in the third case both radiation and conduction were considered as mechanisms of heat transfer. The results show that for typical conditions in a waste package design, the stabilizers are quite effective in reducing the overall temperature in a waste canister. Furthermore, the results show that increasing the stabilizer thickness over the thickness specified in the present design has a negligible effect on the temperature distribution in the canister. Finally, the presence of the stabilizers was found to shift the location of the peak temperature areas in the waste canister

  3. Head stability during quiet sitting in children with cerebral palsy: effect of vision and trunk support.

    Science.gov (United States)

    Saavedra, Sandra; Woollacott, Marjorie; van Donkelaar, Paul

    2010-02-01

    Deficits in postural control are one of the hallmarks of disability in children with cerebral palsy (CP). Yet, much remains unknown regarding the etiology of postural deficits in these children. Here we evaluated postural control at a simplified task level by measuring head stability during quiet sitting while systematically manipulating the level of trunk support and vision in 15 children with CP (6-16 years), 26 typically developing (TD) children (4-14 years), and 11 adults. While TD children did not differ significantly from adults, children with CP had greater head movement than adults in both the sagittal and frontal planes under all conditions except frontal plane movement with Torso Support. Vision did not affect head stability in the sagittal plane for any group while it had differential effects on head stability in the frontal plane. Lack of vision improved head stability in adults and older TD children while destabilizing the head in young children (TD and CP) during the most unstable sitting position. Moreover, vision affected children with CP differently depending on their movement disorder. Children with spastic CP performed worse with eyes closed while those with dyskinetic CP had improved head stability with eyes closed. Our results demonstrate that children with mild to moderate CP have deficits in head stability even during quiet sitting.

  4. Effect of hydrate formation-dissociation on emulsion stability using DSC and visual techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lachance, J.W.; Dendy Sloan, E.; Koh, C.A. [Colorado School of Mines, Golden, CO (United States). Center for Hydrates Research

    2008-07-01

    Many flow assurance operators are now focusing on preventing hydrates from agglomerating and forming plugs within pipelines. A key factor in reducing plug formation in oil-dominated systems is the stability of emulsified water in gas hydrate formation. In this study, differential scanning calorimetry (DSC) studies were used to show that gas hydrate formation has a destabilizing effect on water and oil emulsions, and can result in a free water phase through the coalescence and agglomeration of dissociated hydrate particles. The study focused on investigating the ability of the hydrates to stay segregated with hydrate formation. The stability of water-in-oil emulsions with hydrate formation was investigated with a range of different crude oils with varying emulsion stability levels. Thermal properties were measured at both atmospheric and pressurized conditions. Thermocouples in the calorimetric furnace were used to measure the temperature difference between reference and sample cells. Emulsion stability was measured over a 1-month time period. Results of the study showed that hydrate formation and dissociation destabilizes emulsions. However, the asphaltene fraction in crude oils resists hydrate-induced destabilization. The stability of the emulsion increased when asphaltene content increased. It was concluded that emulsion stability is a key factor in preventing agglomeration in flow lines. 14 refs., 3 tabs., 8 figs.

  5. EFFECTS OF THE BACK-FILLING TO THE STABILITY OF A CAISSON

    Science.gov (United States)

    Kikuchi, Yoshiaki; Shinsha, Hiroshi; Kawamura, Kensuke; Eguchi, Shinya

    The back-filling improves the stability of a caisson used for breakwater against wave force. But, the extent of the improvement of the stability is affected by the interaction among the back-filling and the caisson and the foundation. A series of the model loading experiments was carried out to clarify the effects of the interaction to the stability. In this series of experiments, horizontal static load was applied to the model caisson having back-filling. Sliding failure surface was estimated from the deformation of rubble mound and back-filling. Passive earth pressure by back-filling calculated by wedge theory was compared with the experimental results. New stability evaluation method considering circular arc failure mode was developed and evaluated its validity. Followings are main conclusions in this research; 1) Increment of stability of a caisson against wave force can be estimated from wedge theory. 2) Both sliding and bearing capacity stability were considered in one time using newly developed evaluation method considering circular arc failure mode.

  6. Radiosterilization and steam autoclaving sterilization effects on phosphite antioxidant stability

    Science.gov (United States)

    Yagoubi, N.; Boucherie, P.; Ferrier, D.

    1997-08-01

    While the radiosterilization by γ rays, is mainly employed for medical devices, this procedure is not commonly used to sterilize and decontaminate raw material and finished product used in the pharmaceutical industry. Depending on the countries, the requirements for obtaining approval to treat this class of product with γ rays may be different. Usually it is the responsibility of the manufacturer to demonstrate not only the integrity of the irradiated product, but olso its efficiency, safety and quality. Our work consists of a comparative study of the effects of γ radiotreatment at 25 kGy and steam sterilisation on phosphite antioxidant incorporated in polypropylene. The γ radiosensitivity compared with thermolability of this antioxidant was studied by reversed phase HPLC, Fourier Transform Infrared (IRFT) and Differential Scanning Calorimetry (DSC). The results obtained proved that the phosphite incorporated into the polymer and treated with the two types of sterilisation is rapidly oxidized in phosphate. Nevertheless, this oxidation is more important when using radiotreatment at 25 kGy.

  7. Thermal stability of the krypton Hall effect thruster

    Directory of Open Access Journals (Sweden)

    Szelecka Agnieszka

    2017-03-01

    Full Text Available The Krypton Large IMpulse Thruster (KLIMT ESA/PECS project, which has been implemented in the Institute of Plasma Physics and Laser Microfusion (IPPLM and now is approaching its final phase, was aimed at incremental development of a ~500 W class Hall effect thruster (HET. Xenon, predominantly used as a propellant in the state-of-the-art HETs, is extremely expensive. Krypton has been considered as a cheaper alternative since more than fifteen years; however, to the best knowledge of the authors, there has not been a HET model especially designed for this noble gas. To address this issue, KLIMT has been geared towards operation primarily with krypton. During the project, three subsequent prototype versions of the thruster were designed, manufactured and tested, aimed at gradual improvement of each next exemplar. In the current paper, the heat loads in new engine have been discussed. It has been shown that thermal equilibrium of the thruster is gained within the safety limits of the materials used. Extensive testing with both gases was performed to compare KLIMT’s thermal behaviour when supplied with krypton and xenon propellants.

  8. Climate targets and cost-effective climate stabilization pathways

    Directory of Open Access Journals (Sweden)

    Held H.

    2015-01-01

    Full Text Available Climate economics has developed two main tools to derive an economically adequate response to the climate problem. Cost benefit analysis weighs in any available information on mitigation costs and benefits and thereby derives an “optimal” global mean temperature. Quite the contrary, cost effectiveness analysis allows deriving costs of potential policy targets and the corresponding cost- minimizing investment paths. The article highlights pros and cons of both approaches and then focusses on the implications of a policy that strives at limiting global warming to 2 °C compared to pre-industrial values. The related mitigation costs and changes in the energy sector are summarized according to the IPCC report of 2014. The article then points to conceptual difficulties when internalizing uncertainty in these types of analyses and suggests pragmatic solutions. Key statements on mitigation economics remain valid under uncertainty when being given the adequate interpretation. Furthermore, the expected economic value of perfect climate information is found to be on the order of hundreds of billions of Euro per year if a 2°-policy were requested. Finally, the prospects of climate policy are sketched.

  9. Climate targets and cost-effective climate stabilization pathways

    Science.gov (United States)

    Held, H.

    2015-08-01

    Climate economics has developed two main tools to derive an economically adequate response to the climate problem. Cost benefit analysis weighs in any available information on mitigation costs and benefits and thereby derives an "optimal" global mean temperature. Quite the contrary, cost effectiveness analysis allows deriving costs of potential policy targets and the corresponding cost- minimizing investment paths. The article highlights pros and cons of both approaches and then focusses on the implications of a policy that strives at limiting global warming to 2 °C compared to pre-industrial values. The related mitigation costs and changes in the energy sector are summarized according to the IPCC report of 2014. The article then points to conceptual difficulties when internalizing uncertainty in these types of analyses and suggests pragmatic solutions. Key statements on mitigation economics remain valid under uncertainty when being given the adequate interpretation. Furthermore, the expected economic value of perfect climate information is found to be on the order of hundreds of billions of Euro per year if a 2°-policy were requested. Finally, the prospects of climate policy are sketched.

  10. Static stability analysis of embedded flexoelectric nanoplates considering surface effects

    Science.gov (United States)

    Ebrahimi, Farzad; Barati, Mohammad Reza

    2017-10-01

    In this paper, electromechanical buckling behavior of size-dependent flexoelectric nanoplates is investigated based on nonlocal and surface elasticity theories. Flexoelectricity represents the coupling between strain gradients and electrical polarizations. Flexoelectric nanoplates can tolerate higher buckling loads compared with conventional piezoelectric nanoplates, especially at lower thicknesses. The flexoelectric nanoplate is in contact with a two-parameter elastic foundation, which consists of infinite linear springs and a shear layer. Nonlocal elasticity theory of Eringen is applied in the analysis of flexoelectric nanoplates for the first time. The residual surface stresses which are usually neglected in the modeling of flexoelectric nanoplates are incorporated into nonlocal elasticity to provide better understanding of the physics of the problem. Applying an analytical solution which satisfies various boundary conditions, the governing equations obtained from Hamilton's principle are solved. The reliability of the present approach is verified by comparing the obtained results with those provided in literature. Finally, the influences of nonlocal parameter, surface effect, plate geometrical parameters, elastic foundation and boundary conditions on the buckling characteristics of flexoelectric nanoplates are explored.

  11. Effect of Cement Replacement with Carbide Waste on the Strength of Stabilized Clay Subgrade

    Directory of Open Access Journals (Sweden)

    Muntohar A.S.

    2016-03-01

    Full Text Available Cement is commonly used for soil stabilization and many other ground improvement techniques. Cement is believed to be very good to improve the compressive and split-tensile strength of clay subgrades. In some application cement could be partly or fully replaced with carbide waste. This research is to study the effectiveness of the cement replacement and to find the maximum carbide waste content to be allowed for a clay subgrade. The quantities of cement replaced with the carbide waste were 30, 50, 70, 90, and 100% by its mass. The results show that replacing the cement with carbide waste decreased both the compressive and split tensile strength. Replacing cement content with carbide waste reduced its ability for stabilization. The carbide waste content should be less than 70% of the cement to provide a sufficient stabilizing effect on a clay subgrade.

  12. Investigation of transient stabilizing control effects on turbine-generator shaft torques

    Energy Technology Data Exchange (ETDEWEB)

    Aliyu, U.O.; Choku, A.U.

    1982-08-03

    In this paper, the implementations of some specific transient stabilizing control means, exemplified by dynamic braking resistor, forced excitation and fast turbine valving, are investigated from the view-point of their potential effects on the torsional stresses in a turbine generator shaft system. For the purpose of this study, a state space digital simulation model of one machine infinite bus system is employed whereupon the interactions between the transient stabilizing control schemes, electrical and mechanical subsystems are well represented. The results of the phenomenon under investigation are presented and some pertinent conclusion drawn. In addition, the relative effects of the control means implementations on the turbine generator shaft torques are compared and their benefits from the standpoint of power system stability are discussed.

  13. Effects of high hydrostatic pressure or hydrophobic modification on thermal stability of xanthine oxidase.

    Science.gov (United States)

    Halalipour, Ali; Duff, Michael R; Howell, Elizabeth E; Reyes-De-Corcuera, José I

    2017-08-01

    The effect of high hydrostatic pressure (HHP) on the kinetics of thermal inactivation of xanthine oxidase (XOx) from bovine milk was studied. Inactivation of XOx followed pseudo-first-order kinetics at 0.1-300MPa and 55.0-70.0°C. High pressure up to at least 300MPa stabilized XOx at all the studied temperatures. The highest stabilization effect of HHP on XOx was at 200-300MPa at 55.0 and 58.6°C, and at 250-300MPa at 62.3-70.0°C. The stability of XOx increased 9.5 times at 300MPa and 70.0°C compared to atmospheric pressure at the same temperature. The activation energy of inactivation of XOx decreased with pressure and was 1.9 times less at 300MPa (97.0±8.2kJmol -1 ) than at 0.1MPa (181.7±12.1kJmol -1 ). High pressure decreased the dependence of the rate constant of inactivation to temperature effects compared to atmospheric pressure. The stabilizing effect of HHP on XOx was highest at 70.0°C where the activation volume of inactivation of XOx was 28.9±2.9cm 3 mol -1 . A second approach to try to increase XOx stability involved hydrophobic modification using aniline or benzoate. However, the thermal stability of XOx remained unaffected after 8-14 modifications of carboxyl side groups per XOx monomer with aniline, or 12-17 modifications of amino side groups per XOx monomer with benzoate. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Computational stability appraisal of rectangular natural circulation loop: Effect of loop inclination

    International Nuclear Information System (INIS)

    Krishnani, Mayur; Basu, Dipankar N.

    2017-01-01

    Highlights: • Computational model developed for single-phase rectangular natural circulation loop. • Role of loop inclination to vertical on thermalhydraulic stability is explored. • Inclination has strong stabilizing effect due to lower effective gravitation force. • Increase in tilt angle reduces settling time and highest amplitude of oscillation. • An angle of 15° is suggested for the selected loop geometry. - Abstract: Controlling stability behavior of single-phase natural circulation loops, without significantly affecting its steady-state characteristics, is a topic of wide research interest. Present study explores the role of loop inclination on a particular loop geometry. Accordingly a 3D computational model of a rectangular loop is developed and transient conservation equations are solved to obtain the temporal variation in flow parameters. Starting from the quiescent state, simulations are performed for selected sets of operating conditions and also with a few selected inclination angles. System experiences instability at higher heater powers and also with higher sink temperatures. Inclination is found to have a strong stabilizing influence owing to the reduction in the effective gravitational acceleration and subsequent decline in local buoyancy effects. The settling time and highest amplitude of oscillations substantially reduces for a stable system with a small inclination. Typically-unstable systems can also suppress the oscillations, when subjected to tilting, within a reasonable period of time. It is possible to stabilize the loop within shorter time span by increasing the tilt angle, but at the expense of reduction in steady-state flow rate. Overall a tilt angle of 15° is suggested for the selected geometry. Results from the 3D model is compared with the predictions from an indigenous 1D code. While similar qualitative influence of inclination is observed, the 1D model predicts early appearance of the stability threshold and hence hints

  15. Effect of class F fly ash on fine sand compaction through soil stabilization.

    Science.gov (United States)

    Mahvash, Siavash; López-Querol, Susana; Bahadori-Jahromi, Ali

    2017-03-01

    This paper presents the results of an experimental investigation carried out to evaluate the effect of fly ash (FA) on fine sand compaction and its suitability as a material for embankments. The literature review demonstrates the lack of research on stabilization of sandy material using FA. The study is concerned with the role of FA content in stabilized soil physical characteristics. The main aim of this paper is to determine the optimum quantity of FA content for stabilization of this type of soil. This is achieved through particle size distribution and compaction (standard proctor) tests. The sand was stabilized with three proportions of FA (5%, 10% and 15%) and constant cement content of 3% was used as an activator. For better comparison, the sand was also stabilized by 3% cement only so that the effect of FA could be observed more clearly. The results were in line with the literature for other types of soil, i.e. as the % of FA increases, reduction in maximum dry density and higher optimum moisture content were observed.

  16. The Effect of Core Stability Training on Functional Movement Patterns in Collegiate Athletes.

    Science.gov (United States)

    Bagherian, Sajad; Ghasempoor, Khodayar; Rahnama, Nader; Wikstrom, Erik A

    2018-02-06

    Pre-participation examinations are the standard approach for assessing poor movement quality that would increase musculoskeletal injury risk. However, little is known about how core stability influences functional movement patterns. The primary purpose of this study was to determine the effect of an 8-week core stability program on functional movement patterns in collegiate athletes. The secondary purpose was to determine if the core stability training program would be more effective in those with worse movement quality (i.e. ≤14 baseline FMS score). Quasi-experimental design. Athletic Training Facility. One-hundred collegiate athletes. Functional movement patterns included the Functional Movement Screen (FMS), Lateral step down (LSD) and Y balance test (YBT) and were assessed before and after the 8-week program. Participants were placed into 1 of the 2 groups: intervention and control. The intervention group was required to complete a core stability training program that met 3 times per week for 8-week. Significant group x time interactions demonstrated improvements in FMS, LSD and YBT scores in the experimental group relative to the control group (pcore stability training program enhances functional movement patterns and dynamic postural control in collegiate athletes. The benefits are more pronounced in collegiate athletes with poor movement quality.

  17. Assessing the effects of slippery steel beam coatings to ironworkers' gait stability.

    Science.gov (United States)

    Kim, Hyunsoo; Ahn, Changbum R; Stentz, Terry L; Jebelli, Houtan

    2018-04-01

    Since ironworkers walk and perform their tasks on steel beams, identifying the effects of slippery steel beam surfaces on ironworkers' gait stability-which can be related to safety risk-is critical. However, there is no accepted or validated standard for measuring the slipperiness of coated steel beams, which makes evaluating and controlling for slipperiness a challenge. In this context, this study investigated the effect of the slipperiness of steel beam coatings on ironworkers' gait stability. Accordingly, to identify the relationships between coefficient of friction, perceived slipperiness, and gait stability-represented as the Maximum Lyaponuv exponent (Max LE)-an experiment was conducted with eight different surfaces and sixteen subjects with varying experience as ironworkers. The experiment's results indicate that the slipperiness of the various surfaces greatly affect ironworkers' gait stability while they walk on coated steel beam surfaces. In detail, the Max LE of two subject groups-experienced and inexperienced ironworkers-highly correlated with both the dynamic coefficient of friction values measured by following ANSI B101.3 and with the subjective rating scores of the inexperienced subject group. Unlike subjective rating scores-which were particularly incongruent among experienced workers-the Max LE of inexperienced and experienced subjects has a consistent pattern. This study result highlights an opportunity for using gait stability measurements to quantify and differentiate the safety risks caused by slippery coated steel beams in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The acute effects of vibration training on balance and stability amongst soccer players.

    Science.gov (United States)

    Cloak, Ross; Nevill, Alan; Wyon, Matthew

    2016-01-01

    Acute whole body vibration training (WBVT) is a tool used amongst coaches to improve performance prior to activity. Its effects on other fitness components, such as balance and stability, along with how different populations respond are less well understood. The aim of the current research is to determine the effect of acute WBVT on balance and stability amongst elite and amateur soccer players. Forty-four healthy male soccer players (22 elite and 22 amateur) were assigned to a treatment or control group. The intervention group then performed 3 × 60 seconds static squat on vibration platform at 40 Hz (±4 mm) with Y balance test (YBT) scores and dynamic postural stability index (DPSI) measured pre and post. DPSI was significantly lower in the elite players in the acute WBVT compared to amateur players (F1, 40= 6.80; P = 0.013). YBT anterior reach distance showed a significant improvement in both amateur and elite players in the acute WBVT group (F1, 40= 32.36; P difference in responses to acute high frequency vibration between elite and amateur players during a landing stability task. The results indicate that acute WBVT improves anterior YBT reach distances through a possible improvement in flexibility amongst both elite and amateur players. In conclusion, acute WBVT training appears to improve stability amongst elite soccer players in comparison to amateur players, the exact reasoning behind this difference requires further investigation.

  19. Simulating the effect of hydrate dissociation on wellhead stability during oil and gas development in deepwater

    Science.gov (United States)

    Li, Qingchao; Cheng, Yuanfang; Zhang, Huaiwen; Yan, Chuanliang; Liu, Yuwen

    2018-02-01

    It is well known that methane hydrate has been identified as an alternative resource due to its massive reserves and clean property. However, hydrate dissociation during oil and gas development (OGD) process in deep water can affect the stability of subsea equipment and formation. Currently, there is a serious lack of studies over quantitative assessment on the effects of hydrate dissociation on wellhead stability. In order to solve this problem, ABAQUS finite element software was used to develop a model and to evaluate the behavior of wellhead caused by hydrate dissociation. The factors that affect the wellhead stability include dissociation range, depth of hydrate formation and mechanical properties of dissociated hydrate region. Based on these, series of simulations were carried out to determine the wellhead displacement. The results revealed that, continuous dissociation of hydrate in homogeneous and isotropic formations can causes the non-linear increment in vertical displacement of wellhead. The displacement of wellhead showed good agreement with the settlement of overlying formations under the same conditions. In addition, the shallower and thicker hydrate formation can aggravate the influence of hydrate dissociation on the wellhead stability. Further, it was observed that with the declining elastic modulus and Poisson's ratio, the wellhead displacement increases. Hence, these findings not only confirm the effect of hydrate dissociation on the wellhead stability, but also lend support to the actions, such as cooling the drilling fluid, which can reduce the hydrate dissociation range and further make deepwater operations safer and more efficient.

  20. EFFECT OF CORE STABILITY TRAINING ON DYNAMIC BALANCE IN HEALTHY YOUNG ADULTS - A RANDOMIZED CONTROLLED TRIAL

    Directory of Open Access Journals (Sweden)

    Dhvani N Shah

    2014-10-01

    Full Text Available Background: Balance is a key component of normal daily activities. Therefore, it is necessary to find various programs to improve balance. The core functions to maintain postural alignment and balance during functional activities. The purpose was to study the effects of the core stability training on dynamic balance in healthy, young adults. Methods: It was an interventional study, in which 60 healthy young adults were selected. They were randomly divided into two groups of 30 each, one being experimental group and other control group. Measurement of their height, weight, BMI and leg length was taken. Subjects in both the groups were assessed for core stability with pressure biofeedback unit (PBU and dynamic balance using Star Excursion Balance Test (SEBT pre and post intervention. Subjects in the experimental group underwent progressive core stability training program for six weeks (3days/week and control group was refrained from any type of structured training program. Results: There was statistically significant improvement in core stability and dynamic balance of the experimental group after six weeks of intervention. Conclusion: It is concluded that core stability training of six weeks duration is effective in improving dynamic balance in healthy, young adults.

  1. Stability of Peer Victimization in Early Adolescence: Effects of Timing and Duration

    Science.gov (United States)

    Rueger, Sandra Yu; Malecki, Christine Kerres; Demaray, Michelle Kilpatrick

    2011-01-01

    The current study investigated the stability of peer victimization and the impact of the timing and duration of victimization on psychological and academic outcomes for boys and girls on a sample of 863 middle school students. Results demonstrated strong support for the onset hypothesis and concurrent effects of maladjustment in anxiety,…

  2. Aeolian sand transport and its effects on the stability of Miramar-Caranzalem beach

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, G.V.; Sastry, J.S.

    Removal of sand by wind from the beach at Miramar-Caranzalem, Goa, has been found to effect its stability over a relatively longer time scale. This aeolian sand transport has been computed for this strip of the beach utilising the relation between...

  3. The Effects of pH and Heat Treatment Processing on the Stability of ...

    African Journals Online (AJOL)

    This study was carried out to investigate the effects of pH and heat treatment processing on stability and natural food colours used in dairy products. A repeated laboratory experiment was conducted in which loss of colour intensity or change in shade of natural food colours used in acid and nearly neutral dairy products at ...

  4. Effect of land use patterns on stability and distributions of organic ...

    African Journals Online (AJOL)

    Soil aggregation is important for the resistance of land surfaces to erosion, and it influences the ability of soils to remain productive. At the same time, it is also an important process of carbon sequestration. The objectives of this study were to elucidate the effects of different land use patterns on soil aggregate stability and the ...

  5. Effect of thermal stabilizers (Ba/Cd/Zn metal salts carboxylate and ...

    African Journals Online (AJOL)

    structures or the drop of the glass transition temperature to lower values consequently to chain scission reactions. The effects of stabilizers on PVC decomposition can be investigated by thermogravimetry. Of course, this method is not sensitive enough to be processed without elimination of volatile fragments as for example ...

  6. Effects of Some Chemical Food Additives on the Shelf-Life Stability ...

    African Journals Online (AJOL)

    Effects of Some Chemical Food Additives on the Shelf-Life Stability of Plantain Chips Stored at Ambient Temperature. ... Conclusion: The chemical additives conferred antimicrobial, antioxidant and preservative properties on the plantain chips and therefore prolonged the shelf life up to four weeks. Keywords: Plantain chips ...

  7. Effect of flat insoles with different shore A values on posture stability in diabetic neuropathy

    NARCIS (Netherlands)

    Van Geffen, J.A.; Dijkstra, P.U.; Hof, A.L.; Halbertsma, J.P.K.; Postema, K.

    The objective of the study was to determine whether insoles with a low Shore A value (15 degrees) as prescribed for patients with a diabetic neuropathy have a negative effect on posture stability because these insoles may reduce somatosensory input under the feet. It was conducted in the Center for

  8. Effect of Co on the magnetism and phase stability of lithiated ...

    Indian Academy of Sciences (India)

    Unknown

    Effect of Co on the magnetism and phase stability of lithiated manganese oxides. R PRASAD*, R BENEDEK† and M M THACKERAY†. Department of Physics, Indian Institute of Technology, Kanpur 208 016, India. †Chemical Technology Division, Argonne National Laboratory, Argonne, IL 60439, USA. Abstract. We present ...

  9. Stability of inter-joint coordination during circle drawing: Effects of shoulder-joint articular properties

    NARCIS (Netherlands)

    Bosga, J.; Meulenbroek, R.G.J.; Swinnen, S.P.

    2003-01-01

    The present study addressed the effect of articular conformity of the shoulder joint on the stability of inter-joint coordination during circular drawing movements. Twelve right-handed participants performed clockwise and counter-clockwise circular drawing movements at nine locations in the

  10. Evaluation of the effects of enzyme-based liquid chemical stabilizers on subgrade soils

    CSIR Research Space (South Africa)

    Mgangira, Martin B

    2009-07-01

    Full Text Available The purpose of this study was to asses the strength of enzyme treated soil material. Thus the aim of the paper is to present laboratory results on the effects of two enzyme-based liquid chemicals as soil stabilizers. Soil samples were prepared...

  11. Impulsive effects on global asymptotic stability of delay BAM neural networks

    International Nuclear Information System (INIS)

    Chen Jun; Cui Baotong

    2008-01-01

    Based on the proper Lyapunov functions and the Jacobsthal liner inequality, some sufficient conditions are presented in this paper for global asymptotic stability of delay bidirectional associative memory neural networks with impulses. The obtained results are independently of the delay parameters and can be easily verified. Also, some remarks and an illustrative example are given to demonstrate the effectiveness of the obtained results

  12. Effect of constant heat flux at outer cylinder on stability of viscous ...

    African Journals Online (AJOL)

    DR OKE

    However, in many chemical, electrical and mechanical engineering applications the temperature of both cylinders cannot remain the same. Thus, due to the change in the temperature of both cylinders, there exist a temperature gradient and the stability of the fluid flow is affected by the temperature gradient. The effects of a ...

  13. Effect of stabilization exercise on pain and quality of life of patients ...

    African Journals Online (AJOL)

    Patients with chronic low back pain have lower quality of life compared to patients with other chronic diseases and the general population. This study was designed to assess the effect of stabilization exercises on the quality of life of patients with non-specific chronic low back pain (NSCLBP). A total of 23 patients with ...

  14. Evaluation of the effect of temperature on the stability of metal soaps ...

    African Journals Online (AJOL)

    The thermal stability of calcium and zinc dicarboxylates was studied. The kinetics of the decomposition was studied thermogravimetrically at various temperatures. The rates of the first stage decomposition were used to assess the effect of temperature on the susceptibility of the metal soaps of dicarboxylic acids to ...

  15. The Effects of Radiation on the Linear Stability of a horizontal layer ...

    African Journals Online (AJOL)

    The effect of radiation on the onset of Rayleigh-Benard convection is studied in the case of a radiating Newtonian fluid in a fluid-saturated horizontal porous layer heated from below. The radiative heat transfer is treated using the differential approximation for optically thin limiting case. The linear stability theory is employed ...

  16. Some inelastic effects of thermal cycling on yttria-stabilized zirconia

    Science.gov (United States)

    Hendricks, R. C.; Mcdonald, G.; Bill, R. C.

    1982-01-01

    The effects of inelastic behavior of yttria-stabilized zirconia (YSZ) materials were analyzed. The results show these materials to be sensitive to small changes in temperature and are supported by measurements of inelastic behavior in disc and bar specimens at temperatures as low as 1010 C (1850 F). At higher thermomechanical loadings, the test specimens can deform to strains above 1 percent.

  17. Glycerol, trehalose and glycerol–trehalose mixture effects on thermal stabilization of OCT

    Energy Technology Data Exchange (ETDEWEB)

    Barreca, D., E-mail: dbarreca@unime.it [Dipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy); Laganà, G. [Dipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy); Magazù, S.; Migliardo, F. [Dipartimento di Fisica, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy); Bellocco, E. [Dipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy)

    2013-10-16

    Highlights: • Trehalose influences both enzymatic activity and conformational changes of enzyme. • The results obtained by INS and QENS show a switching-off of the fast dynamics at very low glycerol content. • The diffusive dynamics is slowing down at very low glycerol concentration. • The mixtures of trehalose/glycerol lose the thermal stabilizing effects of pure compounds. - Abstract: The stabilization effects of trehalose, glycerol and their mixtures on ornithine carbamoyltransferase catalytic activity has been studied as a function of temperature by complementary techniques. The obtained results show that the kinematic viscosities of trehalose (1.0 M) and protein mixture are higher than the one of glycerol plus protein. Changing the trehalose/glycerol ratio, we notice a decrease of the kinematic viscosity values at almost all the analyzed ratio. In particular, the solution composed of 95% trehalose-5% glycerol shows a peculiar behavior. Moreover the trehalose (1.0 M) solution shows the higher OCT thermal stabilization at 343 K, while all the other solutions show minor effects. The smallest stabilizing effect is revealed for the solution that shows the maximum kinematic viscosity. These results support Inelastic Neutron Scattering (INS) and Quasi Elastic Neutron Scattering (QENS) findings, which pointed out a slowing down of the relaxation and diffusive dynamics in some investigated samples.

  18. Effect of different stabilizers on the antibacterial activity of “ginger ...

    African Journals Online (AJOL)

    The effect of five stabilizers i.e. citric acid, sodium metabisulfite, sodium benzoate, olive oil and ascorbic acid mixed in the ginger - garlic paste were evaluated against five pathogens (E.coli, Staphylococcus aureus, Salmonella typhi, Proteus mirabilis and Enterobacter aerogenes). Activity of the control paste decreased ...

  19. The effects of permeability and radiation on the stability of plane ...

    African Journals Online (AJOL)

    A study on the effects of permeability and radiation on Couette-Poiseuille flow stability was carried out. Solutions to the governing hydrodynamic equations was developed using the method of undetermined coefficients. On the basis of linear theory using analysis of normal modes, it was observed that both parameters, ...

  20. EFFECTIVENESS OF CORE STABILIZATION EXERCISES AND MOTOR CONTROL EXERCISES IN PATIENTS WITH LOW BACK ACHE

    Directory of Open Access Journals (Sweden)

    Vikranth .G .R

    2015-06-01

    Full Text Available Background: Motor control exercises are isolated strengthening exercise for the deep spinal muscles (transverse abdominus, multifidus whereas Core stability is achieved by global strengthening of the core muscles. There are not much studies available in the literature done or studied the short term effect of the motor control and core stabilization on subjects with low back pain. Therefore, the purpose of this study to find the comparative effect of motor control exercises versus core stabilization exercises on improvement of pain and disability in subjects with mechanical low back pain. Method: An experimental study design, 30 subjects with non-specific mechanical low back pain were randomized into 2 groups with 15 subjects each in Group A and Group B. Subjects in Group A received Motor control exercises and subjects in Group B received Core stability exercises. Both the group received conventional exercises. The duration of intervention was given for two weeks. Outcome measurements such as pain using VAS, Functional disability using Oswestry Disability Index Questionnaire were measured before and after two weeks of intervention. Results: Analysis using paired ‘t’ test and wilcoxon signed rank test found that there is a statistically significant improvement (p<0.05 in pain, functional disability within the groups. Comparative analysis using independent ‘t’ test and Mann Whitney U test for comparison of difference in improvement in VAS and ODI between two groups, it was found that there was significant difference in improvement of VAS and ODI between groups. Group-A showed better improvement in VAS and ODI compared to Group B with an effect size of 1.47 and 0.99 respectively. Conclusion: It is concluded that the Motor control exercises showed statistically significant improvement in reducing back pain and disability when compared to the Core Stabilization exercises. Thus, performing Motor Control exercises reduces pain and disability

  1. Effect of variations in rainfall intensity on slope stability in Singapore

    Directory of Open Access Journals (Sweden)

    Christofer Kristo

    2017-12-01

    Full Text Available Numerous scientific evidence has given credence to the true existence and deleterious impacts of climate change. One aspect of climate change is the variations in rainfall patterns, which affect the flux boundary condition across ground surface. A possible disastrous consequence of this change is the occurrence of rainfall-induced slope failures. This paper aims to investigate the variations in rainfall patterns in Singapore and its effect on slope stability. Singapore's historical rainfall data from Seletar and Paya Lebar weather stations for the period of 1985–2009 were obtained and analysed by duration using linear regression. A general increasing trend was observed in both weather stations, with a possible shift to longer duration rainfall events, despite being statistically insignificant according to the Mann-Kendall test. Using the derived trends, projected rainfall intensities in 2050 and 2100 were used in the seepage and slope stability analyses performed on a typical residual soil slope in Singapore. A significant reduction in factor of safety was observed in the next 50 years, with only a marginal decrease in factor of safety in the subsequent 50 years. This indicates a possible detrimental effect of variations in rainfall patterns on slope stability in Singapore, especially in the next 50 years. The statistical analyses on rainfall data from Seletar and Paya Lebar weather stations for the period of 1985–2009 indicated that rainfall intensity tend to increase over the years, with a possible shift to longer duration rainfall events in the future. The stability analyses showed a significant decrease in factor of safety from 2003 to 2050 due to increase in rainfall intensity, suggesting that a climate change might have existed beyond 2009 with possibly detrimental effects to slope stability. Keywords: Climate change, Rainfall, Seepage, Slope stability

  2. Does the dynamic sling effect of the Latarjet procedure improve shoulder stability? A biomechanical evaluation.

    Science.gov (United States)

    Giles, Joshua W; Boons, Harm W; Elkinson, Ilia; Faber, Kenneth J; Ferreira, Louis M; Johnson, James A; Athwal, George S

    2013-06-01

    Glenohumeral instability with glenoid bone loss is commonly treated with the Latarjet procedure. The procedure involves transfer of the coracoid and conjoint tendon, which is thought to provide a stabilizing sling effect; however, its significance is unknown. This study evaluated the effects of the Latarjet procedure, with and without conjoint tendon loading, on shoulder stability and range of motion (ROM). A custom simulator was used to evaluate anterior shoulder stability and ROM in 8 cadaveric shoulders. Testing conditions included intact, 30% glenoid defect, and Latarjet with and without conjoint loading. Unloaded and 10-N loaded states were tested in adduction and 90° abduction. Outcome variables included dislocation, stiffness (neutral and 60° external rotation), and internal-external rotational ROM. All 30% defects dislocated in abduction external rotation. The loaded Latarjet prevented dislocation in all specimens, whereas the unloaded Latarjet stabilized 6 of 8 specimens. In abduction external rotation, there were no significant differences in stiffness between loaded and unloaded transfers (P = .176). In adduction, there were no significant differences between the intact and the loaded Latarjet (P ≥ .228); however, in neutral rotation, the unloaded Latarjet (P = .015) and the 30% defects (P = .011) were significantly less stiff. Rotational ROM in abduction was significantly reduced with the loaded Latarjet (P = .014) compared with unloaded Latarjet, and no differences were found in adduction. These findings indicate that glenohumeral stability is improved, but not fully restored to intact, with conjoint tendon loading. The results support the existence of the sling effect and its importance in augmenting stability provided by the transferred coracoid. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  3. Effect of core stabilization exercises on functional disability in patients with chronic low back pain

    Directory of Open Access Journals (Sweden)

    Amila Kapetanovic

    2016-04-01

    Full Text Available Introduction: The aim of this study was to assess core stabilization exercise effects in reducing functional disability in patients with chronic low back pain (CLBP.Methods: This study included total of 90 patients aged 40 to 60 years. After a ten-day rehabilitation program the patients from an examination group (n = 30 performed home exercise program five times a week, patients from a first control group (n = 30 three times a week, while patients from a second control group (n = 30 did not perform the exercises at all. The patients performed core stabilization exercises of moderate intensity once a day in 30 minutes sessions. The patient's functional disability was estimated using the Oswestry Disability Index (ODI.Results: After two months of rehabilitation there was a statistically significant increase in functional ability in patients who performed the core stabilization exercises five times a week(p = 0.0001 and in patients who performed the core stabilization exercises three times per week (p = 0.0001. A statistically significant difference in functional ability was not recorded in patients who did not perform the exercises. The analysis of the average values of the ODI differences at the beginning and after two months of rehabilitation showed a statistically significant difference between the group who did not perform the exercises and the group who performed the core stabilization exercises three times a week (p = 0.0001, and between the group who did not perform the exercises and the group who performed the core stabilization exercises five times a week (p = 0.0001.Conclusions: The implementation of the core stabilization exercises leads to a reduction of functional disability in patients with CLBP.

  4. Effect of Filler Concentration on Thermal Stability of Vinyl Copolymer Elastomer (VCE) Composites

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dali [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hubbard, Kevin Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Devlin, David James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Henderson, Kevin C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pacheco, Robin Montoya [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-06

    To study the thermal stability of vinyl copolymer elastomer (VCE) in its composite form, systematic TGA characterizations were conducted in both nonisothermal and isothermal modes. The effects of filler concentration on the aging behaviors of the VCE/filler composites were investigated under nitroplasticizer (NP) environment. FTIR characterization was used to probe the structural changes in the VCE polymer before and after the thermal treatments. This study suggests that the filler concentration significantly deteriorates the thermal stability of NP at a moderate temperature (< 70 °C). The degradation of NP, in turn, accelerates the aging process of the VCE polymer in its composite form.

  5. Mathematical modeling of photoinitiated coating degradation: Effects of coating glass transition temperature and light stabilizers

    DEFF Research Database (Denmark)

    Kiil, Søren; G.de With, R.A.T.M.Van Benthem

    2013-01-01

    A mathematical model, describing coating degradation mechanisms of thermoset coatings exposed to ultraviolet radiation and humidity at constant temperature, was extended to simulate the behavior of a coating with a low glass transition temperature. The effects of adding light stabilizers (a UV......, and simulates the transient development of an oxidation zone. Simulations are in good agreement with experimental data for a fast degrading epoxy-amine coating with a glass transition temperature of −50°C. It was found that the degradation rate of the non-stabilized coating was influenced significantly...

  6. Stability of car following with human memory effects and automatic headway compensation.

    Science.gov (United States)

    Sipahi, Rifat; Niculescu, Silviu-Iulian

    2010-10-13

    This paper addresses the study of some appropriate control strategies in order to guarantee the exponential stability of a class of deterministic microscopic car-following models including human drivers' memory effects and automated headway controllers. More precisely, the delayed action/decision of human drivers is represented using distributed delays with a gap and the considered automated controller is of proportional derivative type. The analysis is performed in both delay parameter and controller gain parameter spaces, and appropriate algorithms are proposed. Surprisingly, large delays and/or gains improve stability for the corresponding closed-loop schemes. Finally, some illustrative examples as well as various interpretations of the results complete the presentation.

  7. The effect and the amendment of thermoregulation to the stability of radon concentration in radon chamber

    International Nuclear Information System (INIS)

    Zhang Xiongjie; Wang Renbo; Qu Jinhui; Tang Bin; Zhu Zhifu; Man Zaigang

    2010-01-01

    When the temperature in the airtight radon chamber was adjusted, it would induce the frequent changes of the air pressure in chamber, then the radon concentration in the radon chamber would continuously reduce, which could seriously destroy the stability of the radon concentration in radon chamber. In this paper, on the study of the effect reasons to the stability of radon concentration in airtight radon chamber due to the thermoregulation, a new amendment scheme was put forward, and the solutions of the relevant parameters were discussed. The amendment scheme had been successfully applied to HD-6 radon chamber, and achieved good results. (authors)

  8. Effects of Resin Refining on the Chemical and Physical Stability of Sardine Oils

    OpenAIRE

    Irianto, Hari Eko

    2014-01-01

    The effect of resin refining on the stability of sardine oil was studied. Fish canning waste oil and fish meal processing waste oil were used in the experiment. The oils were refined by passing through the resin packed column at fish oil and resin ration of 1 : 1.            The fish oil stability was investigated using Schaal oven method by placing the oil in an oven at 63 ± 2oC and the sample was withdrawn after 0, 2, 4, 7 and 11 days. Resin refining improved fish oil quality as indicated b...

  9. Stabilizing effects of a fiber bridge on delamination under compressive load

    Energy Technology Data Exchange (ETDEWEB)

    Daridon, L. [Laboratoire de Mecanique des Multimateriaux Industriels, Strasbourg (France); Zidani, K. [Batna Univ. (Algeria)

    2000-07-01

    Propagation, due to local buckling, of an existing crack in composite plates under compressive load is modelized by an assembly of beams associated with a damageable component localized at crack tip, identified as a fiber bridge. Based upon the model's predictions, an extensive parametric study exhibits a strong stabilizing effect for the fiber bridge. Even for deeply located cracks, the stabilizing length is likely to be reduced by a factor two to four. We finally give a concrete example of prediction of crack propagation behaviour based on parameter values issuing from a DCB test. (orig.)

  10. The effect of walking speed on local dynamic stability is sensitive to calculation methods

    DEFF Research Database (Denmark)

    Stenum, Jan; Bruijn, Sjoerd M; Jensen, Bente Rona

    2014-01-01

    Local dynamic stability has been assessed by the short-term local divergence exponent (λS), which quantifies the average rate of logarithmic divergence of infinitesimally close trajectories in state space. Both increased and decreased local dynamic stability at faster walking speeds have been...... reported. This might pertain to methodological differences in calculating λS. Therefore, the aim was to test if different calculation methods would induce different effects of walking speed on local dynamic stability. Ten young healthy participants walked on a treadmill at five speeds (60%, 80%, 100%, 120......% and 140% of preferred walking speed) for 3min each, while upper body accelerations in three directions were sampled. From these time-series, λS was calculated by three different methods using: (a) a fixed time interval and expressed as logarithmic divergence per stride-time (λS-a), (b) a fixed number...

  11. Experimental and Numerical Investigation of Effect of Air Stability on Exhaled Air Dispersion

    DEFF Research Database (Denmark)

    Xu, Chunwen; Gong, Guangcai; Nielsen, Peter Vilhelm

    2014-01-01

    As more and more investigations have reported the influence of thermal stratification indoors on contaminant dispersion, this paper focuses on investigating this phenomenon from the perspective of air stability which is defined in accordance with atmospheric stability. One breathing thermal manikin...... studies. As the thermal stratification under displacement ventilation blocks the vertical movement of exhaled air, the exhaled contaminant may be trapped between temperature stratifications. As the dispersion of contaminant is closely related to the health of human indoors, the temperature structure...... was used for experimental study, and a numerical person was built to simulate the manikin. The velocity, temperature and concentration of tracer gas in exhaled air are affected by air stability to different degrees. The similarity of this effect among these parameters can also be observed through numerical...

  12. THE EFFECTS OF INOCULANT LACTIC ACID BACTERIA ON THE FERMENTATION AND AEROBIC STABILITY OF SUNFLOWER SILAGE

    Directory of Open Access Journals (Sweden)

    Fisun Koc

    2009-12-01

    Full Text Available This study was carried out to determine the effects of actic acid bacterial inoculant on the fermentation and aerobic stability of sunflower silages. Sunflower was harvested at the milk stage. Inoculant-1174 (Pioneer®,USA was used as homofermentative lactic acid bacterial inoculant. Inoculant was applied 6.00 log10 cfu/g silage levels. Silages with no additive served as controls. After treatment, the chopped sunflower was ensiled in the PVC type laboratory silos. Three silos for each group were sampled for chemical and microbiological analysis on days 2, 4, 7, 14, 21, 28 and 56 after ensiling. At the end of the ensiling period, all silages were subjected to an aerobic stability test for 14 days. Neither inoculant improved the fermentation parameters of sunflower silages. At the end of the ensiling period, inoculant increased lactic acid bacteria (LAB and decreased yeast and mould numbers of silages. Inoculant treatment did not affect aerobic stability of silages.

  13. Stabilizing effect of passive conductors with arbitrary shape for positional instabilities

    International Nuclear Information System (INIS)

    Seki, Shogo; Ninomiya, Hiromasa; Yoshida, Hidetoshi

    1983-10-01

    For positional instabilities in the tokamak, the stabilizing index nsub(s) is an adequate parameter to characterize the stabilizing effect produced by several kinds of passive conductors around a plasma column such as vacuum vessel and poloidal field coils. Since a system of passive conductors with arbitrary shape can be involved into multiple L-R circuits, this parameter nsub(s) of those passive conductors is expressed in a simple form by using a method of the eigen mode expansion of multiple L-R circuits. This parameter nsub(s) is very useful to estimate not only a growth rate of positional instability and its feedback stabilization but also an inward shift of plasma column due to a minor disruption. (author)

  14. Demonstration Results on the Effects of Mercury Speciation on the Stabilization of Wastes

    International Nuclear Information System (INIS)

    Conley, T.B.; Hulet, G.A.; Morris, M.I.; Osborne-Lee, I.W.

    1999-01-01

    Mercury-contaminated wastes are currently being stored at approximately 19 Department of Energy sites, the volume of which is estimated to be about 16m(sup)3. These wastes exist in various forms including soil, sludges, and debris, which present a particular challenge regarding possible mercury stabilization methods. This reports provides the test results of three vendors, Allied Technology Group, IT Corporation, and Nuclear Fuel Services, Inc., that demonstrate the effects of mercury speciation on the stabilization of the mercury wastes. Mercury present in concentrations that exceed 260 parts per million must be removed by extraction methods and requires stabilization to ensure that the final wasteforms leach less than 0.2mg/L of mercury by the Toxicity Characteristic Leaching Procedure or 0.025 mg/L using the Universal Treatment Standard

  15. Game Theoretical Analysis on Cooperation Stability and Incentive Effectiveness in Community Networks.

    Science.gov (United States)

    Song, Kaida; Wang, Rui; Liu, Yi; Qian, Depei; Zhang, Han; Cai, Jihong

    2015-01-01

    Community networks, the distinguishing feature of which is membership admittance, appear on P2P networks, social networks, and conventional Web networks. Joining the network costs money, time or network bandwidth, but the individuals get access to special resources owned by the community in return. The prosperity and stability of the community are determined by both the policy of admittance and the attraction of the privileges gained by joining. However, some misbehaving users can get the dedicated resources with some illicit and low-cost approaches, which introduce instability into the community, a phenomenon that will destroy the membership policy. In this paper, we analyze on the stability using game theory on such a phenomenon. We propose a game-theoretical model of stability analysis in community networks and provide conditions for a stable community. We then extend the model to analyze the effectiveness of different incentive policies, which could be used when the community cannot maintain its members in certain situations. Then we verify those models through a simulation. Finally, we discuss several ways to promote community network's stability by adjusting the network's properties and give some proposal on the designs of these types of networks from the points of game theory and stability.

  16. Game Theoretical Analysis on Cooperation Stability and Incentive Effectiveness in Community Networks.

    Directory of Open Access Journals (Sweden)

    Kaida Song

    Full Text Available Community networks, the distinguishing feature of which is membership admittance, appear on P2P networks, social networks, and conventional Web networks. Joining the network costs money, time or network bandwidth, but the individuals get access to special resources owned by the community in return. The prosperity and stability of the community are determined by both the policy of admittance and the attraction of the privileges gained by joining. However, some misbehaving users can get the dedicated resources with some illicit and low-cost approaches, which introduce instability into the community, a phenomenon that will destroy the membership policy. In this paper, we analyze on the stability using game theory on such a phenomenon. We propose a game-theoretical model of stability analysis in community networks and provide conditions for a stable community. We then extend the model to analyze the effectiveness of different incentive policies, which could be used when the community cannot maintain its members in certain situations. Then we verify those models through a simulation. Finally, we discuss several ways to promote community network's stability by adjusting the network's properties and give some proposal on the designs of these types of networks from the points of game theory and stability.

  17. Effects of noise on postural stability when in the standing position.

    Science.gov (United States)

    Azevedo, Rui; Teixeira, Nuno; Abade, Eduardo; Carvalho, Alberto

    2016-04-06

    Loss of postural stability may result in postural imbalance and can increase the risk of slips and falls in the workplace. This study intended to provide new insight into the effects of noise on postural stability when in the standing position. Twenty healthy subjects voluntarily participated in this study. Their postural stability was analysed using a baropodometry platform under 4 different sets of conditions: i) standing position, without any noise and without wearing ear protectors; ii) standing position, without any noise and wearing ear protectors; iii) standing position, with noise and without wearing ear protectors; iv) standing position, with noise and wearing ear protectors. The results showed that noise at different sound frequencies (400, 2000, 4000 and 8000 Hz) at a level of 95-100 dBA did not affect the participants' postural stability when in the standing position. No significant differences were found in postural balance when participants were exposed to sound with or without ear protectors. Short duration, sensory inputs (i.e. vision) and the absence of physical workloads appear to facilitate postural stability.

  18. The effect of emulsifier on the stability of irradiated LA-TZ latex

    International Nuclear Information System (INIS)

    Made Sumarti K; Utama, Marga; Puspitasari, Tita

    1998-01-01

    The effect of six kinds of stabilizer on the stability of the concentrated LA-TZ latex which contains n-BA have been studied. The six stabilizers are: 1. Naphthalene sulfonic acid formaldehyde condensate, 2. Sodium dialkyl sulfosuccinate, 3. Triethanol amine lauryl sulfate, 4. Sodium polyoxyethylene alkyl phenol ether sulfate, 5. Dodecyl benzene sulfonic acid (Neopelex FS), and 6. Ammonium laurat. The concentrations of the stabilizers are in the range of 0,1 to 0,3% and of the n-BA is 5phr (per hundred rubber). The field natural rubber latex was stabilized by Tetramethyl tiuram disulfide - Zine oxide (TMTD-ZnO) and ammonium gas, and was concentrated by centrifuge. The obtain concentrated LA-TZ latex was added by the n-BA and was kept with various storage time i.e. o, 2, 4, 6, 18, and 24 hours. It was found that the stable latex was irradiated by 15 kGy dose and the physical properties was tested, then the maximum tensile strength of 223,3 kg/cm 2 was found on Neopelex FS concentrate at 0,1%. (authors)

  19. Effect of heavy atoms on the thermal stability of α-amylase from Aspergillus oryzae.

    Directory of Open Access Journals (Sweden)

    Michihiro Sugahara

    Full Text Available Currently, there are no versatile and established methods for improving stability of proteins. In an entirely different approach from conventional techniques such as mutagenesis, we attempted to enhance enzyme stability of α-amylase from Aspergillus oryzae using a heavy-atom derivatization technique. We evaluated changes in stability using differential scanning calorimetry (DSC. Candidate heavy atoms were identified using the Heavy-Atom Database System HATODAS, a Web-based tool designed to assist in heavy-atom derivatization of proteins for X-ray crystallography. The denaturation temperature of α-amylase derivatized with gadolinium (Gd or samarium (Sm ions increased by 6.2 or 5.7°C, respectively, compared to that of the native protein (60.6°C. The binding of six Gd ions was confirmed by X-ray crystallography of the enzyme at 1.5 Å resolution. DSC and dynamic light-scattering data revealed a correlation between stability and the aggregation state upon addition of Gd ions. These results show that HATODAS search is an effective tool for selecting heavy atoms for stabilization of this protein.

  20. Rheological Characteristics of Weak Rock Mass and Effects on the Long-Term Stability of Slopes

    Science.gov (United States)

    Yang, Tianhong; Xu, Tao; Liu, Hongyuan; Zhang, Chunming; Wang, Shanyong; Rui, Yongqin; Shen, Li

    2014-11-01

    The creep deformation behavior of the northern slope of an open-pit mine is introduced. Direct shear creep tests are then conducted for the samples taken from the northern slope to study the rheological characteristics of the rock mass. The experimental results are analyzed afterwards using an empirical method to develop a rheological model for the rock mass. The proposed rheological model is finally applied to understand the creep behavior of the northern slope, predict the long-term stability, and guide appropriate measures to be taken at suitable times to increase the factor of safety to ensure stability. Through this study, a failure criterion is proposed to predict the long-term stability of the slope based on the rheological characteristics of the rock mass and a critical deformation rate is adopted to determine when appropriate measures should be taken to ensure slope stability. The method has been successfully applied for stability analysis and engineering management of the toppling and slippage of the northern slope of the open-pit mine. This success in application indicates that it is theoretically accurate, practically feasible, and highly cost-effective.

  1. Linear time delay methods and stability analyses of the human spine. Effects of neuromuscular reflex response.

    Science.gov (United States)

    Franklin, Timothy C; Granata, Kevin P; Madigan, Michael L; Hendricks, Scott L

    2008-08-01

    Linear stability methods were applied to a biomechanical model of the human musculoskeletal spine to investigate effects of reflex gain and reflex delay on stability. Equations of motion represented a dynamic 18 degrees-of-freedom rigid-body model with time-delayed reflexes. Optimal muscle activation levels were identified by minimizing metabolic power with the constraints of equilibrium and stability with zero reflex time delay. Muscle activation levels and associated muscle forces were used to find the delay margin, i.e., the maximum reflex delay for which the system was stable. Results demonstrated that stiffness due to antagonistic co-contraction necessary for stability declined with increased proportional reflex gain. Reflex delay limited the maximum acceptable proportional reflex gain, i.e., long reflex delay required smaller maximum reflex gain to avoid instability. As differential reflex gain increased, there was a small increase in acceptable reflex delay. However, differential reflex gain with values near intrinsic damping caused the delay margin to approach zero. Forward-dynamic simulations of the fully nonlinear time-delayed system verified the linear results. The linear methods accurately found the delay margin below which the nonlinear system was asymptotically stable. These methods may aid future investigations in the role of reflexes in musculoskeletal stability.

  2. Effects of electron doping on the stability of the metal hydride NaH

    Science.gov (United States)

    Olea-Amezcua, M. A.; Rivas-Silva, J. F.; de la Peña-Seaman, O.; Heid, R.; Bohnen, K. P.

    2017-04-01

    Alkali and alkali-earth metal hydrides have high volumetric and gravimetric hydrogen densities, but due to their high thermodynamic stability, they possess high dehydrogenation temperatures which may be reduced by transforming these compounds into less stable states/configurations. We present a systematic computational study of the electron doping effects on the stability of the alkali metal hydride NaH substituted with Mg, using the self-consistent version of the virtual crystal approximation to model the alloy Na1-x Mg x H. The phonon dispersions were studied paying special attention to the crystal stability and the correlations with the electronic structure taking into account the zero point energy contribution. We found that substitution of Na by Mg in the hydride invokes a reduction of the frequencies, leading to dynamical instabilities for Mg content of 25%. The microscopic origin of these instabilities could be related to the formation of ellipsoidal Fermi surfaces centered at the L point due to the metallization of the hydride by the Mg substitution. Applying the quasiharmonic approximation, thermodynamic properties like heat capacities, vibrational entropies and vibrational free energies as a function of temperature at zero pressure are obtained. These properties determine an upper temperature for the thermodynamic stability of the hydride, which decreases from 600 K for NaH to 300 K at 20% Mg concentration. This significant reduction of the stability range indicates that dehydrogenation could be favoured by electron doping of NaH.

  3. Fuel effects on the stability of turbulent flames with compositionally inhomogeneous inlets

    KAUST Repository

    Guiberti, T. F.

    2016-10-11

    This paper reports an analysis of the influence of fuels on the stabilization of turbulent piloted jet flames with inhomogeneous inlets. The burner is identical to that used earlier by the Sydney Group and employs two concentric tubes within the pilot stream. The inner tube, carrying fuel, can be recessed, leading to a varying degree of inhomogeneity in mixing with the outer air stream. Three fuels are tested: dimethyl ether (DME), liquefied petroleum gas (LPG), and compressed natural gas (CNG). It is found that improvement in flame stability at the optimal compositional inhomogeneity is highest for CNG and lowest for DME. Three possible reasons for this different enhancement in stability are investigated: mixing patterns, pilot effects, and fuel chemistry. Numerical simulations realized in the injection tube highlight similarities and differences in the mixing patterns for all three fuels and demonstrate that mixing cannot explain the different stability gains. Changing the heat release rates from the pilot affects the three fuels in similar ways and this also implies that the pilot stream is unlikely to be responsible for the observed differences. Fuel reactivity is identified as a key factor in enhancing stability at some optimal compositional inhomogeneity. This is confirmed by inference from joint images of PLIF-OH and PLIF-CHO, collected at a repetition rate of 10kHz in turbulent flames of DME, and from one-dimensional calculations of laminar flames using detailed chemistry for DME, CNG, and LPG.

  4. Role of negative hyperconjugation and anomeric effects in the stabilization of the intermediate in SNV reactions.

    Science.gov (United States)

    Karni, Miriam; Bernasconi, Claude F; Rappoport, Zvi

    2008-04-18

    The role of negative hyperconjugation and anomeric and polar effects in stabilizing the XZHCbetaCalphaYY'- intermediates in SNV reactions was studied computationally by DFT methods. Destabilizing steric effects are also discussed. The following ions were studied: X = CH3O, CH3S, CF3CH2O and Y = Y' = Z = H (7b-7d), Y = Y' = H, Z = CH3O, CH3S, CF3CH2O (7e-7i), YY' = Meldrum's acid-like moiety (Mu), Z = H, (8b-8d), and YY' = Mu, Z = CH3O, CH3S, CF3CH2O (8e-8i). The electron-withdrawing Mu substituent at Calpha stabilizes considerably the intermediates and allows their accumulation. The hyperconjugation ability (HCA) (i.e., the stabilization due to 2p(Calpha) --> sigma*(Cbeta-X) interaction) in 8b-8d follows the order (for X, kcal/mol) CH3S (8.5) > CF3CH2O (7.6) approximately CH3O (7.5). The HCA in 8b-8d is significantly smaller than that in 7b-7d due to charge delocalization in Mu in the former. The calculated solvent (1:1 DMSO/H2O) effect is small. The stability of disubstituted ions (7e-7i and 8e-8i) is larger than that of monosubstituted ions due to additional stabilization by negative hyperconjugation and an anomeric effect. However, steric repulsion between the geminal Cbeta substituents destabilizes these ions. The steric effects are larger when one or both substituents are CH3S. The anomeric stabilization (the energy difference between the anti,anti and gauche,gauche conformers) in the disubstituted anions contributes only a small fraction to their total stabilization. Its order (for the following X/Z pairs, kcal/mol) is CF3CH2O/CH3S (8i, 4.9) > CF3CH2O/CH3O (8h, 3.9) > CH3O/CH3S (8g, 3.3) > CH3S/CH3S (8f, 2.9) > CH3O/CH3O (8e, 2.4). Significantly larger anomeric effects of ca. 8-9 kcal/mol are calculated for the corresponding conjugate acids.

  5. Formation of stable and metastable phases in reciprocal systems PbSe + MI2 = MSe + PbI2 (M = Hg, Mn, Sn)

    International Nuclear Information System (INIS)

    Odin, I.N.; Grin'ko, V.V.; Kozlovskij, V.F.; Safronov, E.V.; Gapanovich, M.V.

    2004-01-01

    Using data of differential thermal, X-ray phase and microstructural analyses, phase diagrams of reciprocal systems PbSe + MI 2 = MSe + PbI 2 (M=Hg (1), Mn (2), Sn (3)) were constructed. It was ascertained that the HgSe-PbI 2 diagonal in system 1 is stable. Transformations leading to crystallization of metastable ternary compound formed in the system PbSe-PbI 2 and metastable polytypes of lead iodide in systems 1 and 2 in the range of temperatures from 620 to 685 K were studied. New intermediate metastable phases in systems 1, 2 and 3 were prepared by melt quenching. Crystal lattice parameters of the phases crystallizing in the CdCl 2 structural type were defined [ru

  6. Effect of preparation methods on dispersion stability and electrochemical performance of graphene sheets

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Li, E-mail: chenli1981@lut.cn; Li, Na; Zhang, Mingxia; Li, Pinnan; Lin, Zhengping

    2017-05-15

    Chemical exfoliation is one of the most important strategies for preparing graphene. The aggregation of graphene sheets severely prevents graphene from exhibiting excellent properties. However, there are no attempts to investigate the effect of preparation methods on the dispersity of graphene sheets. In this study, three chemical exfoliation methods, including Hummers method, modified Hummers method, and improved method, were used to prepare graphene sheets. The influence of preparation methods on the structure, dispersion stability in organic solvents, and electrochemical properties of graphene sheets were investigated. Fourier transform infrared microscopy, Raman spectra, transmission electron microscopy, and UV–vis spectrophotometry were employed to analyze the structure of the as-prepared graphene sheets. The results showed that graphene prepared by improved method exhibits excellent dispersity and stability in organic solvents without any additional stabilizer or modifier, which is attributed to the completely exfoliation and regular structure. Moreover, cyclic voltammetric and electrochemical impedance spectroscopy measurements showed that graphene prepared by improved method exhibits superior electrochemical properties than that prepared by the other two methods. - Graphical abstract: Graphene oxides with different oxidation degree were obtained via three methods, and then graphene with different crystal structures were created by chemical reduction of exfoliated graphene oxides. - Highlights: • Graphene oxides with different oxidation degree were obtained via three oxidation methods. • The influence of oxidation methods on microstructure of graphene was investigated. • The effect of oxidation methods on dispersion stability of graphene was investigated. • The effect of oxidation methods on electrochemical properties of graphene was discussed.

  7. Relative Effects of Asymmetry and Wall Slip on the Stability of Plane Channel Flow

    Directory of Open Access Journals (Sweden)

    Sukhendu Ghosh

    2017-12-01

    Full Text Available The effect of wall velocity slip on the stability of a pressure-driven two-dimensional asymmetric channel flow is examined by considering Navier slip condition on the channel walls. The two-parameter families of mean velocity profiles are considered to approximate the underlying asymmetric basic flow. Competing effects of skewness and maximum velocity on the stability of the flow are explored for a range of model parameters. The Orr–Sommerfeld system of the asymmetric flow is solved using a Chebyshev spectral collocation method for both symmetric and non-symmetric type slip boundary conditions. Numerical results indicate that moderate asymmetry in the basic flow has a significant role on the stability of the Poiseuille-kind parallel/nearly parallel flows. Wall slip shows a passive control on the instability of the asymmetric flow by increasing or decreasing the critical Reynolds number and the set of unstable wave numbers. The stabilizing/destabilizing effect of slip velocity on the flow instability is weak or strong depending on the presence of velocity slip at the upper or lower wall. Velocity slip has a profound grip on the flow behaviour by changing the shear rate inside the perturbed flow.

  8. Effect of preparation methods on dispersion stability and electrochemical performance of graphene sheets

    International Nuclear Information System (INIS)

    Chen, Li; Li, Na; Zhang, Mingxia; Li, Pinnan; Lin, Zhengping

    2017-01-01

    Chemical exfoliation is one of the most important strategies for preparing graphene. The aggregation of graphene sheets severely prevents graphene from exhibiting excellent properties. However, there are no attempts to investigate the effect of preparation methods on the dispersity of graphene sheets. In this study, three chemical exfoliation methods, including Hummers method, modified Hummers method, and improved method, were used to prepare graphene sheets. The influence of preparation methods on the structure, dispersion stability in organic solvents, and electrochemical properties of graphene sheets were investigated. Fourier transform infrared microscopy, Raman spectra, transmission electron microscopy, and UV–vis spectrophotometry were employed to analyze the structure of the as-prepared graphene sheets. The results showed that graphene prepared by improved method exhibits excellent dispersity and stability in organic solvents without any additional stabilizer or modifier, which is attributed to the completely exfoliation and regular structure. Moreover, cyclic voltammetric and electrochemical impedance spectroscopy measurements showed that graphene prepared by improved method exhibits superior electrochemical properties than that prepared by the other two methods. - Graphical abstract: Graphene oxides with different oxidation degree were obtained via three methods, and then graphene with different crystal structures were created by chemical reduction of exfoliated graphene oxides. - Highlights: • Graphene oxides with different oxidation degree were obtained via three oxidation methods. • The influence of oxidation methods on microstructure of graphene was investigated. • The effect of oxidation methods on dispersion stability of graphene was investigated. • The effect of oxidation methods on electrochemical properties of graphene was discussed.

  9. TPGS-Stabilized Curcumin Nanoparticles Exhibit Superior Effect on Carrageenan-Induced Inflammation in Wistar Rat

    Directory of Open Access Journals (Sweden)

    Heni Rachmawati

    2016-08-01

    Full Text Available Curcumin, a hydrophobic polyphenol compound derived from the rhizome of the Curcuma genus, has a wide spectrum of biological and pharmacological applications. Previously, curcumin nanoparticles with different stabilizers had been produced successfully in order to enhance solubility and per oral absorption. In the present study, we tested the anti-inflammatory effect of d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS-stabilized curcumin nanoparticles in vivo. Lambda-carrageenan (λ-carrageenan was used to induce inflammation in rats; it was given by an intraplantar route and intrapelurally through surgery in the pleurisy test. In the λ-carrageenan-induced edema model, TPGS-stabilized curcumin nanoparticles were given orally one hour before induction and at 0.5, 4.5, and 8.5 h after induction with two different doses (1.8 and 0.9 mg/kg body weight (BW. Sodium diclofenac with a dose of 4.5 mg/kg BW was used as a standard drug. A physical mixture of curcumin-TPGS was also used as a comparison with a higher dose of 60 mg/kg BW. The anti-inflammatory effect was assessed on the edema in the carrageenan-induced paw edema model and by the volume of exudate as well as the number of leukocytes reduced in the pleurisy test. TPGS-stabilized curcumin nanoparticles with lower doses showed better anti-inflammatory effects, indicating the greater absorption capability through the gastrointestinal tract.

  10. Effect of dispersing and stabilizing additives on rheological characteristics of the upgraded brown coal water mixture

    International Nuclear Information System (INIS)

    Umar, Datin Fatia; Muta'alim; Usui, Hiromoto; Komoda, Yoshiyuki

    2009-01-01

    Upgraded brown coal water mixture (UBCWM) preparation by using an Indonesian upgraded coal produced by upgraded brown coal (UBC) process, was carried out to study the effect of dispersing and stabilizing additives on rheological behavior of the UBCWM. Three kinds of anionic dispersing additives, naphthalene sulfonic formaldehyde condensate (NSF), poly (meth) acrylate (PMA) and poly styrene sulfonic acid (PSS) and three kinds of stabilizing additives, carboxyl methyl cellulose (CMC), rhansam gum (S-194) and gellan gum (S-60) were used in this study. Results indicate that the addition of NSF 0.3 wt.% together with S-194 0.01 wt.% is effective in preparing UBCWM with good slurryability and stability, based on its rheological characteristics with the apparent viscosity at shear rate of 100 s - 1 and yield stress at zero point of shear rate. The rheological behavior of all of the UBCWM that prepared, exhibits non-Newtonian Bingham plastic. From the economical point of view, the price of S-194 is expensive. On the other hand, CMC is cheap and abundant. Therefore, the addition of CMC 0.01 wt.% together with NSF 0.3 wt.% is also effective in preparing UBCWM with good fluidity and stability. (author)

  11. Effect of hesperidin dietary supplementation on hen performance, egg quality and yolk oxidative stability.

    Science.gov (United States)

    Goliomytis, M; Orfanou, H; Petrou, E; Charismiadou, M A; Simitzis, P E; Deligeorgis, S G

    2014-02-01

    1. The purpose of this study was to evaluate the effects of dietary supplementation with hesperidin (one or 3 g/kg of feed) for 31 d on the performance, egg quality and yolk oxidative stability of brown and white laying hens (26-wk old). 2. Supplementation with hesperidin did not affect egg production, egg weight and egg quality traits. 3. No hesperidin effect on yolk and plasma cholesterol was observed. A strain effect was found with lower total and per g yolk cholesterol of brown hens in comparison to the white ones. 4. Oxidative stability of egg yolk, expressed as ng MDA/g yolk, was significantly improved in the hesperidin groups even from the first week of supplementation. At the same time, a significant improvement in the oxidative stability of egg yolk due to the incorporation of hesperidin in hens' diet was observed after 30 and 90 d of storage at 20°C and 4°C, respectively. 5. No hesperidin by strain interaction was detected for any of the traits measured. 6. In conclusion, incorporation of hesperidin to laying hens' feed did not affect productive and egg qualitative traits. On the other hand, dietary hesperidin supplementation significantly improved oxidative stability of both fresh and stored eggs. Antioxidant properties of hesperidin seem to make it a promising natural agent for improving the shelf life of eggs.

  12. Effects of nuclear electromagnetic pulse (EMP) on synchronous stability of the electric power system

    International Nuclear Information System (INIS)

    Manweiler, R.W.

    1975-11-01

    The effects of a nuclear electromagnetic pulse (EMP) on the synchronous stability of the electric power transmission and distribution systems are evaluated. The various modes of coupling of EMP to the power system are briefly discussed, with particular emphasis on those perturbations affecting the synchronous stability of the transmission system. A brief review of the fundamental concepts of the stability problem is given, with a discussion of the general characteristics of transient analysis. A model is developed to represent single sets as well as repetitive sets of multiple faults on the distribution systems, as might be produced by EMP. The results of many numerical stability calculations are presented to illustrate the transmission system's response from different types of perturbations. The important parameters of both multiple and repetitive faults are studied, including the dependence of the response on the size of the perturbed area, the fault density, and the effective impedance between the fault location and the transmission system. Both major load reduction and the effect of the opening of tie lines at the time of perturbation are also studied. We conclude that there is a high probability that EMP can induce perturbations on the distribution networks causing a large portion of the transmission network in the perturbed area to lose synchronism. The result would be an immediate and massive power failure

  13. Rubber effect and stabilization of martensites in noble metal based alloys

    International Nuclear Information System (INIS)

    Marukawa, K.; Takezawa, K.; Hoshi, H.

    1999-01-01

    In a previous paper, it has been pointed out that the rubber effect and stabilization of the martensite phase are caused by short range reordering during aging [K. Marukawa, K. Tsuchiya, Scripta Metall. Mater. 32 (1995) 77]. This view was further examined by experimental and theoretical studies. It has been found that the change in electrical resistivity produced by aging is well correlated with magnitudes of these effects. The relation between the short range order parameters and the representative quantities of these effects was formulated on the basis of thermodynamics. Quantitative evaluation was performed by numerical calculations utilizing the Monte Carlo method. It was found that the rubber effect is prominent when the aging temperature is in the vicinity of the order-disorder transition temperature. It was also shown that in most cases disordering or lowering in the long range order causes the stabilization. (orig.)

  14. Identifying the effects of parameter uncertainty on the reliability of riverbank stability modelling

    Science.gov (United States)

    Samadi, A.; Amiri-Tokaldany, E.; Darby, S. E.

    2009-05-01

    Bank retreat is a key process in fluvial dynamics affecting a wide range of physical, ecological and socioeconomic issues in the fluvial environment. To predict the undesirable effects of bank retreat and to inform effective measures to prevent it, a wide range of bank stability models have been presented in the literature. These models typically express bank stability by defining a factor of safety as the ratio of driving and resisting forces acting on the incipient failure block. These forces are affected by a range of controlling factors that include such aspects as the bank profile (bank height and angle), the geotechnical properties of the bank materials, as well as the hydrological status of the riverbanks. In this paper we evaluate the extent to which uncertainties in the parameterization of these controlling factors feed through to influence the reliability of the resulting bank stability estimate. This is achieved by employing a simple model of riverbank stability with respect to planar failure (which is the most common type of bank stability model) in a series of sensitivity tests and Monte Carlo analyses to identify, for each model parameter, the range of values that induce significant changes in the simulated factor of safety. These identified parameter value ranges are compared to empirically derived parameter uncertainties to determine whether they are likely to confound the reliability of the resulting bank stability calculations. Our results show that parameter uncertainties are typically high enough that the likelihood of generating unreliable predictions is typically very high (> ˜ 80% for predictions requiring a precision of < ± 15%). Because parameter uncertainties are derived primarily from the natural variability of the parameters, rather than measurement errors, much more careful attention should be paid to field sampling strategies, such that the parameter uncertainties and consequent prediction unreliabilities can be quantified more

  15. The Effects of Lyophilization on the Physico-Chemical Stability of Sirolimus Liposomes

    Directory of Open Access Journals (Sweden)

    Parvin Zakeri-Milani

    2013-02-01

    Full Text Available Purpose: The major limitation in the widespread use of liposome drug delivery system is its instability. Lyophilization is a promising approach to ensure the long-term stability of liposomes. The aim of this study was to prepare sirolimus-loaded liposomes, study their stability and investigate the effect of lyophilization either in the presence or in the absence of lyoprotectant on liposome properties. Methods: Two types of multi-lamellar liposomes, conventional and fusogenic, containing sirolimus were prepared by modified thin film hydration method with different ratio of dipalmitoylphosphatidylcholine (DPPC, cholesterol and dioleoylphosphoethanolamine (DOPE, and were lyophilized with or without dextrose as lyoprotectant. Chemical stability investigation was performed at 4°C and 25°C until 6 months using a validated HPLC method. Physical stability was studied with determination of particle size (PS and encapsulation efficiency (EE % of formulations through 6 months. Results: Chemical stability test at 4°C and 25°C until 6 months showed that drug content of liposomes decreased 8.4% and 20.2% respectively. Initial mean EE % and PS were 72.8 % and 582 nm respectively. After 6 months mean EE % for suspended form, lyophilized without lyoprotectant and lyophilized with lyoprotectant were 54.8 %, 62.3% and 67.1 % at 4°C and 48.2%, 60.4 % and 66.8 % at 25°C respectively. Corresponding data for mean PS were 8229 nm, 2397 nm and 688nm at 4°C and 9362 nm, 1944 nm and 737 nm at 25°C respectively. Conclusion: It is concluded that lyophilization with and without dextrose could increase shelf life of liposome and dextrose has lyoprotectant effect that stabilized liposomes in the lyophilization process.

  16. Effects of internal gas pressure on the microstructure and dimensional stability of ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, R.A.; Tally, C.W.; Solomon, A.A.

    1976-01-01

    A new technique has been developed to study the effects of internal and external gas pressure on the dimensional stability and microstructure of ceramics. Preliminary results obtained on pellets of CoO indicate no significant effect of ambient pressure on sintering rates, but at pressures greater than 100 psig, anisotropic shrinkage was observed. After pore closure, reduction of shrinkage was observed. After pore closure, reduction of external pressure led to de-densification or swelling of the sintered body. 9 figures.

  17. Effects of modified β-cyclodextrin on thermal stability and conformation of lysozyme

    International Nuclear Information System (INIS)

    Kamiyama, Tadashi; Satoh, Megumi; Tateishi, Takahiro; Nojiri, Tomoaki; Takeuchi, Daisuke; Kimura, Takayoshi

    2012-01-01

    Highlights: ► Effects of cyclodextrin on stability and conformation of lysozyme were clarified. ► The CD influences the hydrophobic interaction of lysozyme by the inclusion. ► The CD relatively destabilized the folded state by stabilizing the unfolded state. ► The destabilization depends on the concentration and the substituent of CD. ► The conformation of lysozyme was more spread at unfolded state by inclusion of CD. - Abstract: Effects of cyclic oligosaccharide cyclodextrin (CD) on stability and conformation of lysozyme were clarified thermodynamically and rheologically by DSC, viscosity, and circular dichroism measurements. The modified β-CD relatively destabilized the folded state of lysozyme by stabilizing the unfolded state due to inclusion of hydrophobic part into the hydrophobic interior of CD. The order of higher destabilization effect was acetyl-β-CD > methyl-β-CD > hydroxypropyl-β-CD. Apparent number of bound CD to unfolded state for methyl-, hydroxypropyl-, and acetyl-β-CD is 6.7 ± 0.7, 4.2 ± 1.1, and 18.6 ± 4.3 and the binding constant is 5.5 ± 0.8, 6.7 ± 2.4, and 4.4 ± 1.2 L mol −1 , respectively. The viscosity for unfolded state was increased with an increase in the each modified β-CD concentration, suggesting that the inclusion of CD on a part of hydrophobic core at unfolded state leads to break the hydrophobic core, then lysozyme would be more spread structure. The substituent of CD can accelerate instability by directly breaking hydrogen bond and/or can restrain instability by increase in hydrophobic interaction. The fact that the each modified CDs has different destabilization effect shows a possibility to control the stability of protein by the substitution of CD.

  18. Anti-inflammatory Effects of Magnolia sieboldii Extract in ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of Magnolia sieboldii extract (MSE) on the production of pro- inflammatory cytokines by macrophage. Methods: The whole plant of M. sieboldii was extracted with methanol at room temperature. The in vitro anti-inflammatory activity of MSE was investigated on lipopolysaccharide ...

  19. Anti-inflammatory Effects of Magnolia sieboldii Extract in ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of Magnolia sieboldii extract (MSE) on the production of proinflammatory cytokines by macrophage. Methods: The whole plant of M. sieboldii was extracted with methanol at room temperature. The in vitro anti-inflammatory activity of MSE was investigated on lipopolysaccharide ...

  20. Effect of dietary ethanol extracts of mango (Mangifera indica L.) on lipid oxidation and the color of chicken meat during frozen storage.

    Science.gov (United States)

    Freitas, Ednardo Rodrigues; da Silva Borges, Ângela; Pereira, Ana Lúcia Fernandes; Abreu, Virgínia Kelly Gonçalves; Trevisan, Maria Teresa Salles; Watanabe, Pedro Henrique

    2015-12-01

    The aim of this study was to evaluate the dietary effect of mango extracts on lipid stability and the coloring of broiler chicken breast meat during frozen storage. The treatments consisted of broiler chicken diet without antioxidants (control) and diets containing antioxidants: 200 ppm of butylated hydroxytoluene (BHT), 200 ppm of mango peel extract (MPE), 400 ppm of MPE, 200 ppm of mango seed extract (MSE), and 400 ppm of MSE. The broiler breasts were stored for 90 days and analysis of lipid oxidation and color was performed every 30 days. The thiobarbituric acid reactive substances values increased during storage and at 90 days, but the 400 ppm MSE treatment yielded lower values, indicating greater antioxidant activity. During storage, the lightness values decreased and the redness increased. Additions of 200 ppm BHT and 400 ppm MPE increased yellowness at 60 days of storage. Thus, mango peel and seed extracts added to broiler chicken diets reduce lipid oxidation and maintain color in breast meat during frozen storage, with mango seed extract at 400 ppm being the most effective. © 2015 Poultry Science Association Inc.

  1. Effectiveness of the Vertical Gas Ventilation Pipes for Promoting Waste Stabilization in Post-Closure Phase

    Directory of Open Access Journals (Sweden)

    Yasumasa Tojo

    2015-06-01

    Full Text Available To make inside of the municipal solid waste (MSW landfill aerobic as much as possible is thought to be preferable for promoting waste stabilization, reducing pollutant's load in leachate, minimizing greenhouse gas emission and shortening post-closure-care period. In Japan, installation of semi-aerobic landfill structure has widely spread in order to promote waste stabilization in MSW landfill from 1980s. In semi-aerobic landfill structure, outlet of main leachate collection pipe is opened to atmosphere. Heat generated by aerobic degradation of waste causes natural convection and natural aeration arises from the outlet of leachate collection pipe to the gas vents. It is so-called stack effect. This air flow is thought to be effective for purifying leachate flowing through drainage layer and leachate collection pipes. And it is also thought to be contributing to expanding aerobic region in waste layer in landfill. Recently, measures attempting the promotion of waste stabilization are taken at several landfills at where stabilization of waste delays, in which many vertical gas vents are newly installed and close structure to semi-aerobic landfill is created. However, in many cases, these gas vents are not connected to leachate collection pipes. Many vertical gas vents are just installed without scientific proof regarding whether they can contribute for waste stabilization. In this study, how such installation of gas vents is effective for waste stabilization and aerobization of waste layer was discussed by numerical analysis. In numerical analysis, heat transfer, gas movement by pressure, gas diffusion, biological degradation of organic matter, and heat generation by biodegradation were taken into account. Simulations were carried out by using the general purpose simulator of finite element method. Three types of landfill structure were assumed. As the results, the following information were obtained. In dig-down type landfill, installation of gas

  2. Ecological effects of overshooting stabilization targets for greenhouse gases for California plant species

    Science.gov (United States)

    Ries, L. P.; Hannah, L.; Thorne, J.; Seo, C.

    2008-12-01

    Stabilization of global greenhouse gas (GHG) concentrations at or below 350 ppm may be required to avoid catastrophic changes to the climate system. Although the level of stabilization is a primary concern, the pathway to reaching the target should also be considered as some pathways in reaching these goals could have more "dangerous impacts" than others. Since atmospheric GHG stands at 385pppm, achieving a 350ppm target will require overshoot - an exceedance of the target for several decades, followed by a gradual decline back to target levels. The UN Framework Convention on Climate Change aims to stabilize greenhouse gas concentrations to avoid dangerous interference with the climate. The EU has set a goal of 2 C warming. However the current trajectory of greenhouse gas emissions and associated temperature change suggest we are in danger of exceeding these goals and are committed to a certain degree of warming. Ecosystems are one benchmark of acceptable change in international policy, so are a relevant test of the value of low stabilization targets. The biological consequences of overshoot are unknown. Here we simulate the ecological effects of an overshoot strategy for the first time, for a series of California plants. We find that the portion of the species' range defined by the bioclimatic envelope is an important factor in determining the effects of an overshoot scenario and varies between species.

  3. Non-local effects of point mutations on the stability of a protein module

    Science.gov (United States)

    Chwastyk, Mateusz; Vera, Andrés M.; Galera-Prat, Albert; Gunnoo, Melissabye; Thompson, Damien; Carrión-Vázquez, Mariano; Cieplak, Marek

    2017-09-01

    We combine experimental and theoretical methods to assess the effect of a set of point mutations on c7A, a highly mechanostable type I cohesin module from scaffoldin CipA from Clostridium thermocellum. We propose a novel robust and computationally expedient theoretical method to determine the effects of point mutations on protein structure and stability. We use all-atom simulations to predict structural shifts with respect to the native protein and then analyze the mutants using a coarse-grained model. We examine transitions in contacts between residues and find that changes in the contact map usually involve a non-local component that can extend up to 50 Å. We have identified mutations that may lead to a substantial increase in mechanical and thermodynamic stabilities by making systematic substitutions into alanine and phenylalanine in c7A. Experimental measurements of the mechanical stability and circular dichroism data agree qualitatively with the predictions provided the thermal stability is calculated using only the contacts within the secondary structures.

  4. The Effect of Color Selection on the Color Stability of the Resin Cement

    Directory of Open Access Journals (Sweden)

    Merve Çakırbay Tanış

    2017-11-01

    Full Text Available Objective: The aim of this study was to determine effect of shade selection on resin cement’s color stability. Materials and Methods: Ten resin cement samples in dimensions of 10 mm diameter and 2 mm thickness for each group [group 1: Translucent base and translucent catalyst, group 2: Bleach XL (B1 base and yellow (A3 catalyst, group 3: White (A1 base and A3 catalyst] totally 30 samples were prepared. Color coordinates of each sample were recorded after polymerization and 5000 thermal cycles. Color variation (ΔE was calculated for each sample and statistical analyses were performed. Results: The lowest ΔE values were obtained for group 1. Group 2 showed higher ΔE values than group 3 however there were no statistical difference. Conclusion: Translucent base and translucent catalyst mixture showed clinically acceptable color stability while B1 base and A3 catalyst and A1 base and A3 catalyst mixtures did not show clinically acceptable color stability. Shade of the resin cement partially effected its color stability.

  5. Effects of prefabricated ankle orthoses on postural stability in basketball players with chronic ankle instability.

    Science.gov (United States)

    Faraji, Elahe; Daneshmandi, Hassan; Atri, Ahmad Ebrahimi; Onvani, Vahid; Namjoo, Faride Rezaee

    2012-12-01

    Ankle sprain is one of the most common injuries among athletes and instability and injury to this joint is responsible for long time loss of physical and recreational activity. Also, it can impose high costs to sport teams. Prevention of this injury is an important concern of practice and rehabilitation. One way of reducing the possibility of ankle joint injury is using an ankle orthosis. The present study aimed at inspecting the effects of two ankle orthoses on dynamic and semi-dynamic postural stability in athletes with chronic ankle instability (CAI). Twenty basketball players with CAI and fifteen non-injured athletes volunteered to participate in this study. Biodex Balance System was used to assess the participants' postural stability in bilateral position at level 8 and level 2. Repeated measures analysis of variance (ANOVA) was performed in order to examine the effects of ankle orthoses. Statistical significance level was determined at Pankle supports on dynamic and semi-dynamic postural stability in the two groups and results indicated there wasn't significant difference between groups. According to our results the orthoses improved both dynamic and semi-dynamic postural stability. Therefore, orthoses can prevent injury and its reoccurrence.

  6. Protein Stability during Hot Melt Extrusion: The Effect of Extrusion Temperature, Hydrophilicity of Polymers and Sugar Glass Pre-stabilization

    NARCIS (Netherlands)

    Teekamp, Naomi; Olinga, Peter; Frijlink, Henderik W.; Hinrichs, Wouter

    2015-01-01

    Purpose Biodegradable polymers have been widely investigated for controlled release formulations for protein delivery. However, the processing stability of proteins remains a major challenge. The aim of this research is to assess the influence of the hot melt extrusion process on the activity of a

  7. Protein Stability during Hot Melt Extrusion : The Effect of Extrusion Temperature, Hydrophilicity of Polymers and Sugar Glass Pre-stabilization

    NARCIS (Netherlands)

    Teekamp, Naomi; Olinga, Peter; Hinrichs, Wouter; Frijlink, Henderik W.

    2015-01-01

    Purpose Biodegradable polymers have been widely investigated for controlled release formulations for protein delivery. However, the processing stability of proteins remains a major challenge. The aim of this research is to assess the influence of the hot melt extrusion process on the activity of a

  8. Effect of rosemary extract and TBHQ on the stability of radish seed oil

    International Nuclear Information System (INIS)

    Gongling, Z.; Yancheng, G.

    2016-01-01

    The effects of rosemary extract (RE) and tert-Butylhydroquinone (TBHQ) on the storage stability of radish seed oil were studied according to the change of the acid value, peroxide value, tocopherol and sulforaphene in radish seed oil. The results showed that under conditions of accelerated oxidation by (60+-1) degree C, the storage stability of the radish seed oil with antioxidants could be significantly improved, among which TBHQ was better than RE. Besides, RE and TBHQ had a synergistic effect on antioxidation. The compound of 0.01% RE and 0.01% TBHQ had a better antioxidation effect than 0.07% RE and 0.02% TBHQ respectively, which recommended it can be a suitable antioxidant of radish seed oil. (author)

  9. Effect of diatomic islands on step morphological stability of a terrace edge in molecular beam epitaxy

    International Nuclear Information System (INIS)

    Lin, S.; Chu, H.-S.

    1999-01-01

    The effect of two-dimensional diatomic-island nucleation on the linear stability of the step morphology during molecular beam epitaxy is investigated numerically via shooting methods. It is found that the effect of diatomic islands on the step morphological stability is significant. The greater the effects of diatomic islands, the more stable the step morphology. Increasing capture efficiency can decrease the critical surface capillary length and shift the critical wave number toward short-wavelength regimes. The unstable region is shrunk with increasing capture efficiency. Further, increasing flux coverage and/or surface coverage can decrease the critical surface capillary length and shift the critical wave number toward short-wavelength regimes. (orig.)

  10. No effect of odor-induced memory reactivation during REM sleep on declarative memory stability

    Directory of Open Access Journals (Sweden)

    Maren Jasmin Cordi

    2014-09-01

    Full Text Available Memory reactivations in hippocampal brain areas are critically involved in memory consolidation processes during sleep. In particular, specific firing patterns of hippocampal place cells observed during learning are replayed during subsequent sleep and rest in rodents. In humans, experimentally inducing hippocampal memory reactivations during slow-wave sleep (but not during wakefulness benefits consolidation and immediately stabilizes declarative memories against future interference. Importantly, spontaneous hippocampal replay activity can also be observed during rapid-eye movement (REM sleep and some authors have suggested that replay during REM sleep is related to processes of memory consolidation. However, the functional role of reactivations during REM sleep for memory stability is still unclear. Here, we reactivated memories during REM sleep and examined its consequences for the stability of declarative memories. After three hours of early, slow-wave sleep (SWS rich sleep, 16 healthy young adults learned a 2-D object location task in the presence of a contextual odor. During subsequent REM sleep, participants were either re-exposed to the odor or to an odorless vehicle, in a counterbalanced within subject design. Reactivation was followed by an interference learning task to probe memory stability after awakening. We show that odor-induced memory reactivation during REM sleep does not stabilize memories against future interference. We propose that the beneficial effect of reactivation during sleep on memory stability might be critically linked to processes characterizing SWS including, e.g., slow oscillatory activity, sleep spindles or low cholinergic tone, which are required for a successful redistribution of memories from medial temporal lobe regions to neocortical long-term stores.

  11. Effect of Stabilization on Morphology Polystyrene and Supercritical Carbon Dioxide Thermoplastic Foams

    Directory of Open Access Journals (Sweden)

    Mozafar Mokhtari Motameni Shirvan

    2016-01-01

    Full Text Available Microcellular thermoplastic foams can be usually produced in a one-step batch system using a physical foaming agent which is dissolved in a polymer system under specific pressure and temperature, higher than the critical condition of solvent and the glass transition temperature of polymer and solvent mixture. By application of a sudden pressure drop the foam structure is formed through stages of nucleation, growth and coalescence. After pressure drop, if the foam temperature is reduced below the glass transition of the gas-polymer mixture, the cells stop growing which results in a foam with stabilized morphology. This stabilization stage has not been thoroughly focused in previous studies. In this work, polystyrene as a polymer system and supercritical carbon dioxide as a solvent were used at 18.5 MPa pressure and different temperatures. The stabilization process took place within milliseconds and helped to a better understanding of cellular structure in thermoplastic foams. In this mechanism, the nucleation takes place in the phase transition of solvent molecules at supercritical state to the gas state and the formation of very small nuclei containing gas molecules between polymer chains. The energy originated from the nuclei growth is in competition with the elastic energy of polymer chains, and the predominance of one type of energy over another determines the final cell size. The results showed that the effect of stabilization process on the structure of the foam depended on the foaming temperature. Stabilization at 110°C resulted in a 50% cell size reduction and a 60% cell density promotion, while at lower temperatures, the stabilization led to greater cell size and reduced cell density.

  12. Effects of Hall current and electrical resistivity on the stability of gravitating anisotropic quantum plasma

    Science.gov (United States)

    Bhakta, S.; Prajapati, R. P.

    2018-02-01

    The effects of Hall current and finite electrical resistivity are studied on the stability of uniformly rotating and self-gravitating anisotropic quantum plasma. The generalized Ohm's law modified by Hall current and electrical resistivity is used along with the quantum magnetohydrodynamic fluid equations. The general dispersion relation is derived using normal mode analysis and discussed in the parallel and perpendicular propagations. In the parallel propagation, the Jeans instability criterion, expression of critical Jeans wavenumber, and Jeans length are found to be independent of non-ideal effects and uniform rotation but in perpendicular propagation only rotation affects the Jeans instability criterion. The unstable gravitating mode modified by Bohm potential and the stable Alfven mode modified by non-ideal effects are obtained separately. The criterion of firehose instability remains unaffected due to the presence of non-ideal effects. In the perpendicular propagation, finite electrical resistivity and quantum pressure anisotropy modify the dispersion relation, whereas no effect of Hall current was observed in the dispersion characteristics. The Hall current, finite electrical resistivity, rotation, and quantum corrections stabilize the growth rate. The stability of the dynamical system is analyzed using the Routh-Hurwitz criterion.

  13. Effects of wastewater sludge and its detergents on the stability of rotavirus

    Energy Technology Data Exchange (ETDEWEB)

    Ward, R.L. (Sandia Labs., Albuquerque, NM); Ashley, C.S.

    1980-06-01

    Wastewater sludge reduced the heat required to inactivate rotavirus SA-11, and ionic detergents were identified as the sludge components responsible for this effect. A similar result was found previously with reovirus. The quantitative effects of individual ionic detergents on rotavirus and reovirus were very different, and rotavirus was found to be extremely sensitive to several of these detergents. However, neither virus was destabilized by nonionic detergents. On the contrary, rotavirus was stabilized by a nonionic detergent against the potent destabilizing effects of the ionic detergent sodium dodecyl sulfate. The destabilizing effects of both cationic and anionic detergents on rotavirus were greatly altered by changes in the pH of the medium.

  14. Disulfide bond effects on protein stability: designed variants of Cucurbita maxima trypsin inhibitor-V.

    Science.gov (United States)

    Zavodszky, M; Chen, C W; Huang, J K; Zolkiewski, M; Wen, L; Krishnamoorthi, R

    2001-01-01

    Attempts to increase protein stability by insertion of novel disulfide bonds have not always been successful. According to the two current models, cross-links enhance stability mainly through denatured state effects. We have investigated the effects of removal and addition of disulfide cross-links, protein flexibility in the vicinity of a cross-link, and disulfide loop size on the stability of Cucurbita maxima trypsin inhibitor-V (CMTI-V; 7 kD) by differential scanning calorimetry. CMTI-V offers the advantage of a large, flexible, and solvent-exposed loop not involved in extensive intra-molecular interactions. We have uncovered a negative correlation between retention time in hydrophobic column chromatography, a measure of protein hydrophobicity, and melting temperature (T(m)), an indicator of native state stabilization, for CMTI-V and its variants. In conjunction with the complete set of thermodynamic parameters of denaturation, this has led to the following deductions: (1) In the less stable, disulfide-removed C3S/C48S (Delta Delta G(d)(50 degrees C) = -4 kcal/mole; Delta T(m) = -22 degrees C), the native state is destabilized more than the denatured state; this also applies to the less-stable CMTI-V* (Delta Delta G(d)(50 degrees C) = -3 kcal/mole; Delta T(m) = -11 degrees C), in which the disulfide-containing loop is opened by specific hydrolysis of the Lys(44)-Asp(45) peptide bond; (2) In the less stable, disulfide-inserted E38C/W54C (Delta Delta G(d)(50 degrees C) = -1 kcal/mole; Delta T(m) = +2 degrees C), the denatured state is more stabilized than the native state; and (3) In the more stable, disulfide-engineered V42C/R52C (Delta Delta G(d)(50 degrees C) = +1 kcal/mole; Delta T(m) = +17 degrees C), the native state is more stabilized than the denatured state. These results show that a cross-link stabilizes both native and denatured states, and differential stabilization of the two states causes either loss or gain in protein stability. Removal of hydrogen

  15. Differential Effects of Hydrophobic Core Packing Residues for Thermodynamic and Mechanical Stability of a Hyperthermophilic Protein.

    Science.gov (United States)

    Tych, Katarzyna M; Batchelor, Matthew; Hoffmann, Toni; Wilson, Michael C; Hughes, Megan L; Paci, Emanuele; Brockwell, David J; Dougan, Lorna

    2016-07-26

    Proteins from organisms that have adapted to environmental extremes provide attractive systems to explore and determine the origins of protein stability. Improved hydrophobic core packing and decreased loop-length flexibility can increase the thermodynamic stability of proteins from hyperthermophilic organisms. However, their impact on protein mechanical stability is not known. Here, we use protein engineering, biophysical characterization, single-molecule force spectroscopy (SMFS), and molecular dynamics (MD) simulations to measure the effect of altering hydrophobic core packing on the stability of the cold shock protein TmCSP from the hyperthermophilic bacterium Thermotoga maritima. We make two variants of TmCSP in which a mutation is made to reduce the size of aliphatic groups from buried hydrophobic side chains. In the first, a mutation is introduced in a long loop (TmCSP L40A); in the other, the mutation is introduced on the C-terminal β-strand (TmCSP V62A). We use MD simulations to confirm that the mutant TmCSP L40A shows the most significant increase in loop flexibility, and mutant TmCSP V62A shows greater disruption to the core packing. We measure the thermodynamic stability (ΔGD-N) of the mutated proteins and show that there is a more significant reduction for TmCSP L40A (ΔΔG = 63%) than TmCSP V62A (ΔΔG = 47%), as might be expected on the basis of the relative reduction in the size of the side chain. By contrast, SMFS measures the mechanical stability (ΔG*) and shows a greater reduction for TmCSP V62A (ΔΔG* = 8.4%) than TmCSP L40A (ΔΔG* = 2.5%). While the impact on the mechanical stability is subtle, the results demonstrate the power of tuning noncovalent interactions to modulate both the thermodynamic and mechanical stability of a protein. Such understanding and control provide the opportunity to design proteins with optimized thermodynamic and mechanical properties.

  16. Aerodynamic Characteristics of a Feathered Dinosaur Measured Using Physical Models. Effects of Form on Static Stability and Control Effectiveness

    Science.gov (United States)

    Evangelista, Dennis; Cardona, Griselda; Guenther-Gleason, Eric; Huynh, Tony; Kwong, Austin; Marks, Dylan; Ray, Neil; Tisbe, Adrian; Tse, Kyle; Koehl, Mimi

    2014-01-01

    We report the effects of posture and morphology on the static aerodynamic stability and control effectiveness of physical models based on the feathered dinosaur, Microraptor gui, from the Cretaceous of China. Postures had similar lift and drag coefficients and were broadly similar when simplified metrics of gliding were considered, but they exhibited different stability characteristics depending on the position of the legs and the presence of feathers on the legs and the tail. Both stability and the function of appendages in generating maneuvering forces and torques changed as the glide angle or angle of attack were changed. These are significant because they represent an aerial environment that may have shifted during the evolution of directed aerial descent and other aerial behaviors. Certain movements were particularly effective (symmetric movements of the wings and tail in pitch, asymmetric wing movements, some tail movements). Other appendages altered their function from creating yaws at high angle of attack to rolls at low angle of attack, or reversed their function entirely. While M. gui lived after Archaeopteryx and likely represents a side experiment with feathered morphology, the general patterns of stability and control effectiveness suggested from the manipulations of forelimb, hindlimb and tail morphology here may help understand the evolution of flight control aerodynamics in vertebrates. Though these results rest on a single specimen, as further fossils with different morphologies are tested, the findings here could be applied in a phylogenetic context to reveal biomechanical constraints on extinct flyers arising from the need to maneuver. PMID:24454820

  17. Effect of Ratio of Visco-Elastic Material Viscosity to Fluid Viscosity on Stability of Flexible Pipe Flow

    Science.gov (United States)

    ANBUKUMAR, S.; KUMAR, MUNENDRA

    2017-08-01

    In the present study, a flexible pipe has been considered to study the effect of ratio of visco-elastic material viscosity to fluid viscosity on the stability of flexible laminar pipe flow with axi-symmetric disturbances. The effect of thickness of visco-elastic material on the stability of flexible pipe flow with outer rigid shroud has also been studied. The stability curves are drawn for various values of the ratio of visco-elastic material viscosity to fluid viscosity. It is observed that stability of flow is increasing by decreasing the ratio of visco-elastic material viscosity to fluid viscosity.

  18. Effect of a new pelvic stabilizer (T-POD) on reduction of pelvic volume and haemodynamic stability in unstable pelvic fractures.

    NARCIS (Netherlands)

    Tan, E.C.T.H.; Stigt, S.F. van; Vugt, A.B. van

    2010-01-01

    BACKGROUND: Pelvic fractures, often the result of high energy blunt trauma, are associated with severe morbidity and mortality. A new pelvic stabilizer (T-POD) provides secure and effective simultaneous circumferential compression of the pelvis. METHODS: In this study we describe 15 patients with a

  19. Effect of stabilizers, oil level and structure on the growth of Zygosaccharomyces bailii and on physical stability of model systems simulating acid sauces.

    Science.gov (United States)

    Zalazar, Aldana L; Gliemmo, María F; Campos, Carmen A

    2016-07-01

    The effect of xanthan gum, guar gum, oil and the structure promoted by these compounds on the growth of Zygosaccharomyces bailii and on physical stability of emulsified systems simulating acid sauces was studied. Furthermore, the effect of yeast growth on physical stability of emulsions was also evaluated. Yeast growth was evaluated by plate count and modeled by the modified Gompertz equation. Emulsions characteristics and their stability were determined by droplet size, zeta potential and rheological measurements. The latter was also used to evaluate structure's effect on yeast growth. Physical characteristics of emulsions depended on system composition. Yeasts slightly affected droplet size. Z. bailii growth was satisfactorily modeled by the modified Gompertz equation. The specific growth rate (μ m ) and the asymptotic value (A) obtained depended on xanthan gum, guar gum and oil content. Furthermore, the structure promoted by these compounds exerted a significant effect on growth. In general, an increase in the solid character and yield stress through the addition of xanthan gum promoted a decrease in A parameter. On the contrary, a decrease in the solid character through the addition of guar gum promoted an increase in the A parameter. The results obtained stressed that stabilizers, oil and their structuring ability play an important role on Z. bailii growth. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Laboratory research on tailings stabilization methods and their effectiveness in radiation containment

    International Nuclear Information System (INIS)

    Macbeth, P.J.; Jensen, C.M.; Rogers, V.C.; Overmyer, R.F.

    1978-04-01

    This report describes a study of various methods, techniques, and materials for stabilizing uranium mill tailings to reduce radon exhalation. Radon emanation from tailings particles, radon exhalation from tailings, and methods that could be used to reduce radon exhalation from tailings piles are discussed. Surface radon flux and soil gas concentrations were measured in experiment chambers or columns consisting of uranium tailings and various types and thicknesses of cover materials. The applicability of diffusion theory was examined and effective diffusion coefficients were determined for clay, soil, and sand. The variation of radon flux with atmospheric effects and moisture also was investigated. The effectiveness of several types of chemical stabilizers for both volumetric and surface application in reducing radon exhalation is reported. Some volumetric stabilizers reduced radon flux by 90 percent or more. Radon flux was determined through the use of charcoal gas mask canisters, and flux accumulation chambers sampled by Lucas cells. Both of these techniques are described. Soil gas concentration was sampled with Lucas cells and counted with a sodium iodide scintillation spectrometer system. Emanating power of uranium tailings was measured for several particle sizes and found to be relatively constant at about 20 percent. Two types of grasses were found that would grow in tailings if sufficient water and fertilizer were provided. The effect of vegetation on radon exhalation was not determined

  1. ARTHROMETRIC EVALUATION OF STABILIZING EFFECT OF KNEE FUNCTIONAL BRACING AT DIFFERENT FLEXION ANGLES

    Directory of Open Access Journals (Sweden)

    Saeedeh Seyed Mohseni

    2009-06-01

    Full Text Available Previous in-vivo investigations on the stabilizing efficacy of knee bracing for ACL reconstructed patients have been often limited to 20-30 degrees of knee flexion. In this study, the effectiveness of a uniaxial hinged functional brace to improve the knee stability was assessed at 30, 60 and 90 degrees of knee flexion. Arthrometry tests were conducted on 15 healthy subjects before and following wearing the brace and the tibial displacements were measured at up to 150 N anterior forces. Results indicated that functional bracing has a significant stabilizing effect throughout the range of knee flexion examined (p < 0.05. The rate of effectiveness, however, was not consistent across the flexion range, e.g., 50% at 30 degrees and only 4% at 90 degrees. It was suggested that accurate sizing and fitting as well as attention to correct hinge placement relative to the femoral condyles can limit brace migration and improve its effectiveness in mid and deep knee flexion. With using adaptive limb fittings, through flexible pads, and a polycentric joint a more significant improvement of the overall brace performance and efficacy might be obtained

  2. Effect of cinnamaldehyde on oxidative stability of several fats and oils at elevated temperatures

    Directory of Open Access Journals (Sweden)

    Tuğba İnanç Horuz

    2015-12-01

    Full Text Available Natural antioxidants recently have gained popularity since synthetic ones have toxic and carcinogenic effects. In the present study, effect of temperature (120, 150 and 180°C and cinnamaldehyde on oxidative stability of several oils (olive, hazelnut and palm oils and fats (milkfat and butter was examined. In order to compare the results with the synthetic antioxidant, butylated hydroxy toluene (BHT was used at a concentration of 200 ppm. This level is the legal maximum limit allowed. Experiments were conducted by using a PetroOxy device, a rapid small scale oxidation stability test. According to induction time values obtained by PetroOxy device, the stability of oils drastically decreased with increasing temperature. Cinnamaldehyde had no significant effect (p > 0.05 on all fat and oil samples compared to control (no antioxidant added and BHT added samples. BHT significantly increased induction times of all fat and oil samples at lower temperatures. However, it was not effective at 180°C (p < 0.05. It can be concluded that cinnamaldehyde could not be considered as a good alternative to BHT for preservation of fats and oils at high temperatures.

  3. Development of lyophilization cycle and effect of excipients on the stability of catalase during lyophilization

    Science.gov (United States)

    Lale, Shantanu V; Goyal, Monu; Bansal, Arvind K

    2011-01-01

    Introduction: The purpose of the present study was to screen excipients such as amino acids and non-aqueous solvents for their stabilizing effect on catalase, a model protein, for lyophilization. The present study also includes optimization of lyophilization cycle for catalase formulations, which is essential from the commercial point of view, since lyophilization is an extremely costly process. Materials and Methods: Activity of catalase was determined using catalase activity assay. Differential scanning calorimetry was used to determine eutectic melting temperature of the frozen catalase solution, which is essential for the optimization of lyophilization cycle. Results: When catalase was lyophilized without excipients, it was found that about 65-78% of the initial activity of catalase was lost during the lyophilization process in a concentration dependent manner. The maximum stability of catalase during lyophilization was observed at pH 7.0. Amino acids like alanine, glycine, lysine, serine and 4-hydroxy proline showed strong stabilizing effect on catalase during lyophilization by protecting catalase activity above 95%, whereas valine and cysteine hydrochloride showed destabilizing effect on catalase. Non-aqueous solvents such as dimethyl formamide, dimethyl sulphoxide, polyethylene glycol (PEG) 200, PEG 400, PEG 600 and ethylene glycol also showed destabilizing effect on catalase during lyophilization. Conclusions: In order to prevent loss of catalase activity during lyophilization of catalase, use of amino acids like alanine, glycine, lysine, serine and 4-hydroxy proline in optimum concentration is highly advisable. PMID:23071946

  4. Sulfate anion stabilization of native ribonuclease A both by anion binding and by the Hofmeister effect.

    Science.gov (United States)

    Ramos, Carlos H I; Baldwin, Robert L

    2002-07-01

    Data are reported for T(m), the temperature midpoint of the thermal unfolding curve, of ribonuclease A, versus pH (range 2-9) and salt concentration (range 0-1 M) for two salts, Na(2)SO(4) and NaCl. The results show stabilization by sulfate via anion-specific binding in the concentration range 0-0.1 M and via the Hofmeister effect in the concentration range 0.1-1.0 M. The increase in T(m) caused by anion binding at 0.1 M sulfate is 20 degrees at pH 2 but only 1 degree at pH 9, where the net proton charge on the protein is near 0. The 10 degrees increase in T(m) between 0.1 and 1.0 M Na(2)SO(4), caused by the Hofmeister effect, is independent of pH. A striking property of the NaCl results is the absence of any significant stabilization by 0.1 M NaCl, which indicates that any Debye screening is small. pH-dependent stabilization is produced by 1 M NaCl: the increase in T(m) between 0 and 1.0 M is 14 degrees at pH 2 but only 1 degree at pH 9. The 14 degree increase at pH 2 may result from anion binding or from both binding and Debye screening. Taken together, the results for Na(2)SO(4) and NaCl show that native ribonuclease A is stabilized at low pH in the same manner as molten globule forms of cytochrome c and apomyoglobin, which are stabilized at low pH by low concentrations of sulfate but only by high concentrations of chloride.

  5. Microstructure and rheology of particle stabilized emulsions: Effects of particle shape and inter-particle interactions.

    Science.gov (United States)

    Katepalli, Hari; John, Vijay T; Tripathi, Anubhav; Bose, Arijit

    2017-01-01

    Using fumed and spherical silica particles of similar hydrodynamic size, we investigated the effects of particle shape and inter-particle interactions on the formation, stability and rheology of bromohexadecane-in-water Pickering emulsions. The interparticle interactions were varied from repulsive to attractive by modifying the salt concentration in the aqueous phase. Optical microscope images revealed smaller droplet sizes for the fumed silica stabilized emulsions. All the emulsions remained stable for several weeks. Cryo-SEM images of the emulsion droplets showed a hexagonally packed single layer of particles at oil-water interfaces in emulsions stabilized with silica spheres, irrespective of the nature of the inter-particle interactions. Thus, entropic, excluded volume interactions dominate the fate of spherical particles at oil-water interfaces. On the other hand, closely packed layers of particles were observed at oil-water interfaces for the fumed silica stabilized emulsions for both attractive and repulsive interparticle interactions. At the high salt concentrations, attractive inter-particles interactions led to aggregation of fumed silica particles, and multiple layers of these particles were then observed on the droplet surfaces. A network of fumed silica particles was also observed between the emulsion droplets, suggesting that enthalpic interactions are responsible for the determining particle configurations at oil-water interfaces as well as in the aqueous phase. Steady shear viscosity measurements over a range of shear stresses, as well as oscillatory shear measurements at 1Hz confirm the presence of a network in fumed silica suspensions and emulsions, and the lack of such a network when spherical particles are used. The fractal structure of fumed silica leads to several contact points and particle interlocking in the water as well as on the bromohexadecane-water interfaces, with corresponding effects on the structure and rheology of the emulsions

  6. Effect of active arm swing to local dynamic stability during walking.

    Science.gov (United States)

    Wu, Yu; Li, Yue; Liu, An-Min; Xiao, Fei; Wang, Yin-Zhi; Hu, Fei; Chen, Jin-Ling; Dai, Ke-Rong; Gu, Dong-Yun

    2016-02-01

    Arm swing is an essential component in regulating dynamic stability of the whole body during walking, while the contribution of active arm swing to local dynamic stability of different motion segments remains unclear. This study investigated the effects of arm swing under natural arm swing condition and active arm swing condition on local dynamic stability and gait variability of the trunk segments (C7 and T10 joint) and lower extremity joints (hip, knee and ankle joint). The local divergence exponents (λs) and mean standard deviation over strides (MeanSD) of 24 young healthy adults were calculated while they were walking on treadmill with two arm swing conditions at their preferred walking speed (PWS). We found that in medial-lateral direction, both λs and MeanSD values of the trunk segments (C7 and T10 joint) in active arm swing condition were significantly lower than those in natural arm swing condition (parm swing conditions (p>0.05, respectively). In anterior-posterior and vertical direction, neither λs nor MeanSD values of all body segments showed significant difference between two arm swing conditions (p>0.05, respectively). These findings indicate that active arm swing may help to improve the local dynamic stability of the trunk segments in medial-lateral direction. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Effect of confining stress and fluid properties on arch stability in unconsolidated sands

    Energy Technology Data Exchange (ETDEWEB)

    Cleary, M.P.; Kohlhaas, C.A.; Melvan, J.J.

    1979-01-01

    A cylindrical sand pack, 52.75 in. long x 16 in. in diameter, was used to study the stability of unconsolidated sands across casing perforations. Bottom-hole producing conditions were approximated with overburden stresses of 250, 750, 1500, 2250, and 3000 psig. Fluid saturations consisted of an irreducible water phase and liquid hydrocarbons. The sand used was gopher state 20/40 frac sand, and the different hydrocarbon fluids investigated were kerosine and mineral spirits. The observed mechanism of sand stabilization around a well bore was the formation of sand arches across a perforation opening; an observation consistent with those of earlier investigations. Hence, sand instability was recorded at the moment of failure of sand arches. Arch structure is a function of the stress distribution in a sand pack. Maximum arch size and stability were also found to be a function of confining stress. The effect of different hydrocarbons on arch stability manifests itself in the cohesive forces in the pendular saturation of the wetting phase at the arch wall.

  8. Effect of Alkaline Activator to Fly Ash Ratio for Geopolymer Stabilized Soil

    Directory of Open Access Journals (Sweden)

    Abdullah Muhammad Sofian

    2017-01-01

    Full Text Available Geopolymer technology have been developed and explored especially in the construction material field. However, lack of research related to geopolymer stabilized soil. In this research, the utilization of geopolymer has been investigated to stabilize the soil including the factors that affecting the geopolymerization process. Unconfined compressive test (UCT used as indicator to the strength development and hence evaluating the performance of geopolymer stabilized soil. This paper focusing on the effect of fly ash/alkaline activator ratio, Na2SiO3/NaOH ratio and curing time on geopolymer stabilized soil. A various mix design at different fly ash/alkaline activator ratio, Na2SiO3/NaOH ratio were prepared and cured for 7 and 28 days. Molarity and the percentage of geopolymer to soil were fixed at 10 molar and 8 percent respectively. Then, the UCT tests were carried out on 38mm diameter x 76mm height specimens. The highest strength obtained at the fly ash/alkaline activator ratio 2.5 and Na2SiO3/NaOH ratio 2.0 at 28 days curing time.

  9. The copper nanoparticles catalysed reduction of substituted nitrobenzenes: effect of nanoparticle stabilizers

    Science.gov (United States)

    Santhanalakshmi, J.; Parimala, L.

    2012-09-01

    Copper nanoparticles are prepared and size characterized using FESEM and HRTEM. Poly ethylene glycol (PEG), carboxy methyl cellulose (CMC) and poly N vinyl pyrrolidone (PVP) are used as the nanoparticle stabilizers. The reduction reactions of fourteen differently aromatic ring substituted nitro benzenes are carried out with NaBH4 solution catalyzed by the copper nanoparticles with PEG, CMC and PVP as stabilizers. Using time variance UV absorbance spectra, the progress of the reactions are kinetically monitored, the parameters such as product % yield, time of reaction and rate coefficient values are determined and used for deducing the comparative catalytic efficiency. The copper nanoparticles as synthesized using biopolymers such as PEG and CMC produce better reaction parameters than the PVP stabilized Cu nps. Also the effect of substituents in the aromatic ring of the nitro compounds reveals that -I substituents containing nitro compounds are better catalyzed than the +I substituents. The sizes of the three Cu nps are found to be 6, 12 and 15 nm corresponding to PEG, CMC and PVP stabilizers respectively.

  10. Stochastic description of cascade size effects on phase stability under irradiation

    International Nuclear Information System (INIS)

    Martin, G.; Bellon, P.

    1988-01-01

    Cascade size may affect phase stability under irradiation because of two distinct contributions: the replacement to displacement cross section ratio depends on the deposited energy density; ballistic jumps which tend to disorder ordere compounds occur by bursts (of size b), while thermal jumps which restored long range order occur one by one. The latter effect cannot be handled by standard rate theory. A stochastic treatment of the problem, based on a Fokker Planck approximation of the relevant master equation is summarized. It is shown that the possible values of the long range order parameter under irradiation are not affected by the size b of the bursts, but that the respective stability of the former is b dependent. As a consequence, the stability diagram of phases under irradiation varies with b. Such a diagram is computed for the Ni 4 Mo system where three structures are competing: the disordered solid solution, D1 a and DO 23 . A broadening by 100K of the stability domain of the short range ordered structure to the expense of the long range ordered one is predicted when increasing b from 1 to 100. The stochastic potentials introduced in the present treatment are by no means free energies of some constrained state. They can however be computed in a mean field type approximation. 23 refs

  11. Effect of wing form on the hydrodynamic characteristics and dynamic stability of an underwater glider

    Directory of Open Access Journals (Sweden)

    Muhammad Yasar Javaid

    2017-07-01

    Full Text Available We are developing a prototype underwater glider for subsea payload delivery. The idea is to use a glider to deliver payloads for subsea installations. In this type of application, the hydrodynamic forces and dynamic stability of the glider is of particular importance, as it has implications on the glider's endurance and operation. In this work, the effect of two different wing forms, rectangular and tapered, on the hydrodynamic characteristics and dynamic stability of the glider were investigated, to determine the optimal wing form. To determine the hydrodynamic characteristics, tow tank resistance tests were carried out using a model fitted alternately with a rectangular wing and tapered wing. Steady-state CFD analysis was conducted using the hydrodynamic coefficients obtained from the tests, to obtain the lift, drag and hydrodynamic derivatives at different angular velocities. The results show that the rectangular wing provides larger lift forces but with a reduced stability envelope. Conversely, the tapered wing exhibits lower lift force but improved dynamic stability.

  12. Effect of liquid density differences on boiling two-phase flow stability

    International Nuclear Information System (INIS)

    Furuya, Masahiro; Manera, Annalisa; Bragt, David D.B.; Hagen, Tim H.J.J. van der; Kruijf, Willy J.M.de

    2002-01-01

    In order to investigate the effect of considering liquid density dependence on local fluid temperature in the thermal-hydraulic stability, a linear stability analysis is performed for a boiling natural circulation loop with an adiabatic riser. Type-I and Type-II instabilities were to investigate according to Fukuda-Kobori's classification. Type-I instability is dominant when the flow quality is low, while Type-II instability is relevant at high flow quality. Type-II instability is well known as the typical density wave oscillation. Neglecting liquid density differences yields estimates of Type-II instability margins that are too small, due to both a change in system-dynamics features and in the operational point. On the other hand, neglecting liquid density differences yields estimates of Type-I stability margins that are too large, especially due to a change in the operational point. Neglecting density differences is thus non-conservative in this case. Therefore, it is highly recommended to include liquid density dependence on the fluid subcooling in the stability analysis if a flow loop with an adiabatic rise is operated under the condition of low flow quality. (author)

  13. Enhanced stability of black phosphorus field-effect transistors with SiO₂ passivation.

    Science.gov (United States)

    Wan, Bensong; Yang, Bingchao; Wang, Yue; Zhang, Junying; Zeng, Zhongming; Liu, Zhongyuan; Wang, Wenhong

    2015-10-30

    Few-layer black phosphorus (BP) has attracted much attention due to its high mobility and suitable band gap for potential applic5ations in optoelectronics and flexible devices. However, its instability under ambient conditions limits its practical applications. Our investigations indicate that by passivation of the mechanically exfoliated BP flakes with a SiO2 layer, the fabricated BP field-effect transistors (FETs) exhibit greatly enhanced environmental stability. Compared to the unpassivated BP devices, which show a fast drop of on/off current ratio by a factor of 10 after one week of ambient exposure, the SiO2-passivated BP devices display a high retained on/off current ratio of over 600 after one week of exposure, just a little lower than the initial value of 810. Our investigations provide an effective route to passivate the few-layer BPs for enhancement of their environmental stability.

  14. DFT study of stabilization effects on N-doped graphene for ORR catalysis

    DEFF Research Database (Denmark)

    Reda, Mateusz; Hansen, Heine Anton; Vegge, Tejs

    2018-01-01

    is explained by a high reactivity of *O and *O2, which possess empty O(sp) states. At 6.25% N, the reaction environment is found to comprise *O and free nitrogen spectators. Finally, strong *O solvation is found to be present in a broader class of systems, comprising all materials where the ORR occurs on a 2nd...... solvation stabilizes all ORR intermediates, having a greater impact on *O and *O2, than on *OH and *OOH, in contrast to metal and oxide catalysts. Synergistic stabilization of *O caused by both effects reaches remarkably a high value of 1.5 eV for nitrogen concentrations above 4.2% N. Such a strong effect...... row element. Including at least a single explicit water layer is paramount to achieve the correct description of the ORR intermediates adsorption energies on these materials....

  15. Precipitation Effect on Mechanical Properties and Phase Stability of High Manganese Steel

    Science.gov (United States)

    Bae, Cheoljun; Kim, Rosa; Lee, Un-Hae; Kim, Jongryoul

    2017-09-01

    High manganese (Mn) steels are attractive for automotive applications due to their excellent tensile strength and superior elongation. However, the relatively low yield strength of Mn steels compared to other advanced high-strength steels is a critical problem limiting their use in structural parts. In order to increase the yield strength, the precipitation hardening effect of Mn steels was investigated by the addition of carbide-forming elements. Changes in the austenite phase stability were also evaluated in terms of stacking fault energy (SFE). As a result, fine V(C,N) precipitates were found to increase the yield strength effectively but to lower the SFE by the consumption of matrix carbons. For achieving precipitation hardening without sacrificing austenite stability, the soluble carbon content was discussed.

  16. THE EFFECT OF DIFFERENT EXPOSURE CONDITIONS ON THE CHARACTERISTICS OF THE MINERAL MATRICES STABILIZING HAZARDOUS WASTE

    Directory of Open Access Journals (Sweden)

    Anna Król

    2016-05-01

    Full Text Available Mineral binders are more and more often used in the difficult process of disposal of inorganic hazardous waste containing heavy metals. Composites solidifying hazardous waste are deposited in the environment, which exposes them to the interaction of many variable factors. The paper presents the effect of different exposure conditions on physical and mechanical properties of concrete stabilizing galvanic sewage sludge (GO. The effect of the cyclic freezing and thawing, carbon dioxide (carbonation and high temperatures (200 °C, 400 °C, 600 °C on the properties of stabilizing matrices has been described. The results, in most cases, show a loss of durability of composites solidifying sewage sludge (GO by the influence of external conditions.

  17. Effects of Dynamic Misalignements and Feedback Performance on Luminosity Stability in Linear Colliders

    CERN Document Server

    Seryi, Andrei; Raubenheimer, T O; Tenenbaum, P G; Woodley, M; Schulte, Daniel

    2003-01-01

    The performance of high energy linear colliders depends critically on the stability with which they can maintain the collisions of nanometer-size beams. Ground motion and vibration, among other effects, will produce dynamic misalignments which can offset the beams at the collision point. A system of train-to-train and intra-train beam-beam feedbacks, possibly combined with additional beam-independent active systems, is planned to compensate for these effects. Extensive simulation studies of ground motion and luminosity stabilization have been performed as part of the work of the International Linear Collider Technical Review Committee [1]. This paper presents a comparison of the expected performance for TESLA, JLC/NLC and CLIC under various assumptions about feedbacks and the level of ground motion.

  18. Dietary supplementation of garlic and rosemary: effects on colour stability and lipid oxidation in lamb meat

    Directory of Open Access Journals (Sweden)

    M. Scafizzari

    2010-01-01

    Full Text Available The colour of fresh meat is an important criterion consumers take into consideration when purchasing meat. Meat colour depends on the occurrence of chemical and microbial deterioration processes. The role of vitamin E and other antioxidants on ruminant meat colour stability and prevention of lipid oxidation has been widely investigated (Macit et al., 2003; Realini et al., 2004. Many natural herbs and plant extracts exert antioxidant effects such as garlic (Yin and Cheng, 2003 and rosemary (Sánchez-Escalante et al., 2001. Their use as additives for animal feeding may be a valid alternative to synthetic antioxidants since they show beneficial effects also on animal welfare and other physiological functions (Tedesco, 2001. The aim of this study was to evaluate whether garlic and rosemary dietary supplementation as compared with vitamin E affects lamb meat colour and lipid stability during storage.

  19. Lake restoration with aluminium, bentonite and Phoslock: the effect on sediment stability and light attenuation

    DEFF Research Database (Denmark)

    Egemose, Sara; Reitzel, Kasper; Flindt, Mogens

    treatments on aluminium mobility, sediment stability or light climate. A laboratory flume experiment including three shallow Danish lakes was conducted. We measured the effects of aluminium, Phoslock (a commercial product), bentonite, and a combination of bentonite/aluminium. Each treatment caused a varying...... consolidation of the sediment. The largest consolidation occurred using Phoslock- and bentonite-addition followed by bentonite/aluminium-addition, whereas aluminium alone had no effect. Sediment stability thresholds were measured before and after addition. Especially Phoslock, but also bentonite and bentonite....../aluminium increased sediment erosion threshold, with respectively 200%, 43% and 57%. Aluminium, bentonite/aluminium, and Phoslock improved the light conditions in the water phase, with respectively 60%, 57% and 50%, whereas bentonite created higher turbidity. Conclusively aluminium improved the light conditions...

  20. Anti-gastritis and wound healing effects of Momordicae Semen extract and its active component.

    Science.gov (United States)

    Jung, Kiwon; Chin, Young-Won; Chung, Yoon Hee; Park, Yang Hae; Yoo, Hunseung; Min, Dong Sun; Lee, Bongyong; Kim, Jinwoong

    2013-02-01

    Momordicae Semen, Momordica cochinchinensis Springer (Cucurbitaceae), has long been known to effectively relieve boils, rheumatic pain, and hemorrhoids. In this study, we investigated whether Momordicae Semen extract (MSE) has anti-gastritis effects in various rodent models and also explored possible mechanisms for the gastroprotective effects of MSE. MSE provided remarkable protective effects, comparable to those of rebamipide, in ethanol- and diclofenac-induced acute gastritis. In addition, it has demonstrated protective effect in a Helicobacter pylori-insulted chronic gastritis model. MSE also showed wound healing effect on cutaneous injury of mice and stimulated calcitonin gene-related peptide and somatostatin receptors, which may be related to its anti-gastritis effects. In a single oral dose toxicity study, the approximate lethal dose of MSE was determined at >2000 mg/kg/day. The NOAEL was set to be 2000 mg/kg/day from the repeated oral dose toxicity study. Moreover, momordica saponin I, a major ingredient of MSE, treatment decreased gastric mucosa damage indices in the ethanol- and diclofenac-induced acute gastritis models. The results suggest that MSE could be a promising gastroprotective herbal medicine and momordica saponin I might be used as an active marker compound for MSE.

  1. The effect of exchange-correlation on change and stability of crystal structure

    International Nuclear Information System (INIS)

    Yazdani, A.; Niazi, M.; Alimardan, V.

    2007-01-01

    Since exchange interaction energy has effect on band structure via polarization of spin of free electron, then can directly effects formation crystal structure. Therefore exchange-correlation is able to have an effect on determination of crystal structure or its change and stability. This energy is subject to fluctuation range of electrons between conduction band and valance band or density of electrons which due to increase the entropy of system, via Gibss Energy .We investigated these factors: 1) Size of ions 2) Density of States 3) Range of inter atomic and pair-potential.

  2. Scaling behaviour of the effective chiral action and stability of the chiral soliton

    International Nuclear Information System (INIS)

    Reinhardt, H.

    1986-12-01

    The effective chiral action is evaluated within a novel improved heat-kernel expansion, which includes gradients of the chiral field in a non-perturbative way. The exact scaling behaviour of the effective action of a localized chiral field with respect to changing its spatial size is found. From this it is proved that the radiatively induced derivative terms cannot absolutely stabilize the chiral soliton against collapsing. The collapsing of the soliton is, however, accompanied by a vanishing of the baryon charge. It is argued that the effective chiral action constrained to a fixed baryon number may still admit stable soliton configurations. (orig.)

  3. The effect of protein complexation on the mechanical stability of Im9.

    Science.gov (United States)

    Hann, Eleanore; Kirkpatrick, Nadine; Kleanthous, Colin; Smith, D Alastair; Radford, Sheena E; Brockwell, David J

    2007-05-01

    Force mode microscopy can be used to examine the effect of mechanical manipulation on the noncovalent interactions that stabilize proteins and their complexes. Here we describe the effect of complexation by the high affinity protein ligand E9 on the mechanical resistance of the simple four-helical protein, Im9. When concatenated into a construct of alternating I27 domains, Im9 unfolded below the thermal noise limit of the instrument ( approximately 20 pN). Complexation of E9 had little effect on the mechanical resistance of Im9 (unfolding force approximately 30 pN) despite the high avidity of this complex (K(d) approximately 10 fM).

  4. Effects of Outlets on Cracking Risk and Integral Stability of Super-High Arch Dams

    OpenAIRE

    Lin, Peng; Liu, Hongyuan; Li, Qingbin; Hu, Hang

    2014-01-01

    In this paper, case study on outlet cracking is first conducted for the Goupitan and Xiaowan arch dams. A nonlinear FEM method is then implemented to study effects of the outlets on integral stability of the Xiluodu arch dam under two loading conditions, i.e., normal loading and overloading conditions. On the basis of the case study and the numerical modelling, the outlet cracking mechanism, risk, and corresponding reinforcement measures are discussed. Furthermore, the numerical simulation re...

  5. Effects of different encapsulation agents and drying process on stability of betalains extract

    OpenAIRE

    Ravichandran, Kavitha; Palaniraj, Ravichandran; Saw, Nay Min Min Thaw; Gabr, Ahmed M. M.; Ahmed, Abdelrahman R.; Knorr, Dietrich; Smetanska, Iryna

    2012-01-01

    Red beet plants are rich in betalains that can be used as food natural colorants. Betalains were extracted from red beet and encapsulated with different carrier agents and freeze or spray dried. Effect of different encapsulating agents as maltodextrin, guar gum, gum Arabic, pectin and xanthan gum with different concentration (as encapsulating agents) were studied on the betalain stability. Encapsulated betalains with xanthan gum with maltodextrin showed about 65 % more recovery than the contr...

  6. The Effects of growing Indian military potential on South Asian stability

    Science.gov (United States)

    2017-06-09

    response. Both sides will then be engaged in a series of actions and counteractions leading to a potential ascent up the escalation ladder. If...national power and military potential . The dangerous outcome associated with these actions is the primary cause of instability in South Asia. In this...THE EFFECTS OF GROWING INDIAN MILITARY POTENTIAL ON SOUTH ASIAN STABILITY A thesis presented to the Faculty of the U.S. Army

  7. Effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction

    OpenAIRE

    Shim, Jae-Kwang; Choi, Ho-Suk; Shin, Jun-Ho

    2015-01-01

    [Purpose] This study examined the effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 16 adults who underwent arthroscopic anterior cruciate reconstruction and neuromuscular training. The Lysholm scale was used to assess functional disorders on the affected knee joint. A KT-2000 arthrometer was used to measure anterior displacement of the tibia against the femur. Surface electromyography was used t...

  8. Leaching of concrete : the leaching process : extrapolation of deterioration : effect on the structural stability

    OpenAIRE

    Fagerlund, Göran

    2000-01-01

    The leaching process when water attacks concrete, and the effect of leaching on the strength and durability of a concrete structure, is analysed theoretically. Technique for prediction of the future leaching and structural stability is outlined. The analysis is to a certain extent supported by data from literature. The leaching process is divided in five different types: 1: Pure surface leaching 2: Surface leaching involving erosion 3: Homogeneous leaching over the entire structure 4...

  9. Hydrodynamic Fluid Film Bearings and Their Effect on the Stability of Rotating Machinery

    Science.gov (United States)

    2006-11-01

    Refer to [2] for details on the analytical solution of Eqn. (18). This is not the case for squeeze film dampers (SFDs), however, since the long...on Finite Length Sealed Squeeze Film Dampers , L. San Andrés & J.M. Vance, ASLE Transactions, 30, 3, pp. 384-393, 1987. [5] Turbomachinery...RTO-EN-AVT-143 10 - 1 Hydrodynamic Fluid Film Bearings and Their Effect on the Stability of Rotating Machinery Luis San Andrés Mast

  10. Stabilizing effect of gas conductivity evolution on the resistive sausage mode of a propagating beam

    International Nuclear Information System (INIS)

    Lampe, M.; Joyce, G.

    1983-01-01

    Previous theoretical work has shown that a highly current-neutralized charged particle beam propagating in a preionized plasma channel of fixed conductivity is subject to a resistive sausage instability. It is shown that the instability is stabilized, for the case of beam propagation into an initially un-ionized gas, when the effect of beam-collisional ionization on the gas conductivity is modeled fully self-consistently

  11. Effect of habitat degradation on competition, carrying capacity, and species assemblage stability.

    Science.gov (United States)

    Calizza, Edoardo; Costantini, Maria Letizia; Careddu, Giulio; Rossi, Loreto

    2017-08-01

    Changes in species' trophic niches due to habitat degradation can affect intra- and interspecific competition, with implications for biodiversity persistence. Difficulties of measuring species' interactions in the field limit our comprehension of competition outcomes along disturbance gradients. Thus, information on how habitat degradation can destabilize food webs is scarce, hindering predictions regarding responses of multispecies systems to environmental changes. Seagrass ecosystems are undergoing degradation. We address effects of Posidonia oceanica coverage reduction on the trophic organization of a macroinvertebrate community in the Tyrrhenian Sea (Italy), hypothesizing increased trophic generalism, niche overlap among species and thus competition and decreased community stability due to degraded conditions. Census data, isotopic analysis, and Bayesian mixing models were used to quantify the trophic niches of three abundant invertebrate species, and intra- and interspecific isotopic and resource-use similarity across locations differing in seagrass coverage. This allowed the computation of (1) competition strength, with respect to each other and remaining less abundant species and (2) habitat carrying capacity. To explore effects of the spatial scale on the interactions, we considered both individual locations and the entire study area ("'meadow scale"). We observed that community stability and habitat carrying capacity decreased as P. oceanica coverage declined, whereas niche width, similarity of resource use and interspecific competition strength between species increased. Competition was stronger, and stability lower, at the meadow scale than at the location scale. Indirect effects of competition and the spatial compartmentalization of species interactions increased stability. Results emphasized the importance of trophic niche modifications for understanding effects of habitat loss on biodiversity persistence. Calculation of competition coefficients based

  12. System Performance of an Inertially Stabilized Gimbal Platform with Friction, Resonance, and Vibration Effects

    OpenAIRE

    Jia, Ruting; Nandikolla, Vidya K.; Haggart, Gary; Volk, Charles; Tazartes, Daniel

    2017-01-01

    The research work evaluates the quality of the sensor to perform measurements and documents its effects on the performance of the system. It also evaluates if this performance changes due to the environments and other system parameters. These environments and parameters include vibration, system friction, structural resonance, and dynamic system input. The analysis is done by modeling a gimbal camera system that requires angular measurements from inertial sensors and gyros for stabilization. ...

  13. Effect of mobilities and electric field on the stability of magnetized positive column

    International Nuclear Information System (INIS)

    Dogra, V.K.; Uberoi, M.S.

    1983-01-01

    The effect of ratio of the mobilities of electrons and ions and non-dimensional electric field, on the stability of magnetized positive column for all unstable modes is studied in a self-consistent formulation for the perturbations of plasma density and electric potential. The minimum non-dimensional electric field at which magnetized positive column becomes unstable for different ratios of the mobilities of electrons and ions is also investigated. (author)

  14. Effects of smartphone texting on the visual perception and dynamic walking stability

    OpenAIRE

    Lim, Jongil; Chang, Seung Ho; Lee, Jihyun; Kim, Kijeong

    2017-01-01

    Mobile phone use while walking can cause dual-task interference and increases safety risks by increasing attentional and cognitive demands. While the interference effect on cognitive function has been examined extensively, how perception of the environment and walking dynamics are affected by mobile phone use while walking is not well understood. The amount of visual information loss and its consequent impact on dynamic walking stability was examined in this study. Young adults (mean, 20.3 ye...

  15. Development of lyophilization cycle and effect of excipients on the stability of catalase during lyophilization

    OpenAIRE

    Lale, Shantanu V; Goyal, Monu; Bansal, Arvind K

    2011-01-01

    Introduction: The purpose of the present study was to screen excipients such as amino acids and non-aqueous solvents for their stabilizing effect on catalase, a model protein, for lyophilization. The present study also includes optimization of lyophilization cycle for catalase formulations, which is essential from the commercial point of view, since lyophilization is an extremely costly process. Materials and Methods: Activity of catalase was determined using catalase activity assay. Differen...

  16. Effect of Storage Period on Dimensional Stability of Alginplus and Hydrogum 5

    OpenAIRE

    Shima Aalaei; Rohollah Ganj-Khanloo; Fatemeh Gholami

    2017-01-01

    Objectives: This study aimed to evaluate the effect of storage period on dimensional stability of Alginplus and Hydrogum 5.Materials and Methods: In this in vitro experimental study, 60 impressions were taken of an upper jaw typodont, including 10 impressions for each storage period to be tested (12 minutes, 24 and 120 hours) for each type of alginate. Then, the impressions were stored in an incubator with stable temperature and humidity, and poured using a type III dental stone. Subsequently...

  17. Effects of Lumbar Core Stability Exercise Programme on Knee Pain, Range of Motion, and Function Post Anterior Cruciate Ligament Reconstruction

    Directory of Open Access Journals (Sweden)

    Priyanka Panchal

    2017-12-01

    Conclusion: Institutional conventional exercise protocol is effective in reducing pain and improving the ROM post and lumbar core stability exercise programme is effective in improving function, post ACL reconstruction.

  18. Study on the Effect of Air Throttling on Flame Stabilization of an Ethylene Fueled Scramjet Combustor

    Directory of Open Access Journals (Sweden)

    Ye Tian

    2015-01-01

    Full Text Available The effect of air throttling on flame stabilization of an ethylene fueled scramjet combustor was investigated by numerical simulation and experiments in this paper. The results were obtained under the inflow condition with Mach number of 2.0, total temperature of 900 K, total pressure of 0.8 MPa, and total equivalence ratio of 0.5. The shock train generated by air throttling had a big effect on the flow structure of the scramjet combustor. Compared with the combustor without air throttling, the flow field with air throttling had a lower velocity and higher pressure, temperature, and vortices intensity. Air throttling was an effective way to achieve flame stabilization; the combustion in the combustor without air throttling was nearly blowout. In the experiment, the combustion was nearly blowout with air throttling location of 745 mm, and the fuel/air mixture in the combustor with air throttling location of 875 mm was burned intensively. It was important to choose the location and time sequence of air throttling for fuel ignition and flame stabilization. The numerical simulation results agreed well with experimental measurements.

  19. Salt effects on the conformational stability of the visual G-protein-coupled receptor rhodopsin.

    Science.gov (United States)

    Reyes-Alcaraz, Arfaxad; Martínez-Archundia, Marlet; Ramon, Eva; Garriga, Pere

    2011-12-07

    Membrane protein stability is a key parameter with important physiological and practical implications. Inorganic salts affect protein stability, but the mechanisms of their interactions with membrane proteins are not completely understood. We have undertaken the study of a prototypical G-protein-coupled receptor, the α-helical membrane protein rhodopsin from vertebrate retina, and explored the effects of inorganic salts on the thermal decay properties of both its inactive and photoactivated states. Under high salt concentrations, rhodopsin significantly increased its activation enthalpy change for thermal bleaching, whereas acid denaturation affected the formation of a denatured loose-bundle state for both the active and inactive conformations. This behavior seems to correlate with changes in protonated Schiff-base hydrolysis. However, chromophore regeneration with the 11-cis-retinal chromophore and MetarhodopsinII decay kinetics were slower only in the presence of sodium chloride, suggesting that in this case, the underlying phenomenon may be linked to the activation of rhodopsin and the retinal release processes. Furthermore, the melting temperature, determined by means of circular dichroism and differential scanning calorimetry measurements, was increased in the presence of high salt concentrations. The observed effects on rhodopsin could indicate that salts favor electrostatic interactions in the retinal binding pocket and indirectly favor hydrophobic interactions at the membrane protein receptor core. These effects can be exploited in applications where the stability of membrane proteins in solution is highly desirable. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  20. Salt Effects on the Conformational Stability of the Visual G-Protein-Coupled Receptor Rhodopsin

    Science.gov (United States)

    Reyes-Alcaraz, Arfaxad; Martínez-Archundia, Marlet; Ramon, Eva; Garriga, Pere

    2011-01-01

    Membrane protein stability is a key parameter with important physiological and practical implications. Inorganic salts affect protein stability, but the mechanisms of their interactions with membrane proteins are not completely understood. We have undertaken the study of a prototypical G-protein-coupled receptor, the α-helical membrane protein rhodopsin from vertebrate retina, and explored the effects of inorganic salts on the thermal decay properties of both its inactive and photoactivated states. Under high salt concentrations, rhodopsin significantly increased its activation enthalpy change for thermal bleaching, whereas acid denaturation affected the formation of a denatured loose-bundle state for both the active and inactive conformations. This behavior seems to correlate with changes in protonated Schiff-base hydrolysis. However, chromophore regeneration with the 11-cis-retinal chromophore and MetarhodopsinII decay kinetics were slower only in the presence of sodium chloride, suggesting that in this case, the underlying phenomenon may be linked to the activation of rhodopsin and the retinal release processes. Furthermore, the melting temperature, determined by means of circular dichroism and differential scanning calorimetry measurements, was increased in the presence of high salt concentrations. The observed effects on rhodopsin could indicate that salts favor electrostatic interactions in the retinal binding pocket and indirectly favor hydrophobic interactions at the membrane protein receptor core. These effects can be exploited in applications where the stability of membrane proteins in solution is highly desirable. PMID:22261069

  1. Effects of Fourteen-Day Bed Rest on Trunk Stabilizing Functions in Aging Adults

    Directory of Open Access Journals (Sweden)

    Nejc Sarabon

    2015-01-01

    Full Text Available Bed rest has been shown to have detrimental effects on structural and functional characteristics of the trunk muscles, possibly affecting trunk and spinal stability. This is especially important in populations such as aging adults with often altered trunk stabilizing functions. This study examined the effects of a fourteen-day bed rest on anticipatory postural adjustments and postural reflex responses of the abdominal wall and back muscles in sixteen adult men. Postural activation of trunk muscles was measured using voluntary quick arm movement and sudden arm loading paradigm. Measurements were conducted prior to the bed rest, immediately after, and fourteen days after the bed rest. Immediately after the bed rest, latencies of anticipatory postural adjustments showed significant shortening, especially for the obliquus internus and externus muscles. After a fourteen-day recuperation period, anticipatory postural adjustments reached a near to complete recovery. On the contrary, reactive response latencies increased from pre-bed-rest to both post-bed-rest measurement sessions. Results indicate an important effect of bed rest on stabilizing functions of the trunk muscles in elderly adults. Moreover, there proved to be a significant deterioration of postural reactive responses that outlasted the 14-day post-bed-rest rehabilitation.

  2. Soil aggregate stability as an indicator for eco-engineering effectiveness?

    Science.gov (United States)

    Graf, Frank

    2015-04-01

    Eco-engineering aims at stabilising soil and slopes by applying technical and biological measures. Engineering structures are commonly well defined, immediately usable and operative, and their stability effects quantifiable and verifiable. Differently, the use of plants requires more restrictive boundary conditions and the protection potential is rarely easily calculable and develop-ing as a function of growth rate. Although the use of vegetation is widely appreciated and their stabilising effect recognised, there is an increasing demand on sound facts on its efficiency, in particular, in relation to time. Conclusively, a certain necessity has been recognised to monitor, assess and quantify the effectiveness of ecological restora-tion measures in order to facilitate the transfer of technology and knowledge. Recent theoretical models emphasize the im-portance of taking an integrated monitoring approach that considers multiple variables. However, limited financial and time resources often prevent such comprehensive assessments. A solution to this problem may be to use integrated indicators that reflect multiple aspects and, therefore, allow extensive information on ecosystem status to be gathered in a relatively short time. Among various other indicators, such as fractal dimension of soil particle size distribution or microbiological parameters, soil aggregate stability seems the most appropriate indicator with regard to protecting slopes from superficial soil failure as it is critical to both plant growth and soil structure. Soil aggregation processes play a crucial role in re-establishing soil structure and function and, conclusively, for successful and sustainable re-colonisation. Whereas the key role of soil aggregate stability in ecosystem functioning is well known concerning water, gas, and nutrient fluxes, only limited information is available with regard to soil mechanical and geotechnical aspects. Correspondingly, in the last couple of years several studies

  3. EFFECT OF SHOULDER SIDE PACK ON DYNAMIC POSTURAL STABILITY IN YOUNG HEALTHY FEMALE

    Directory of Open Access Journals (Sweden)

    Enas ELsayed Mohamed Abutaleb

    2016-06-01

    Full Text Available Background: Control of balance is a complex motor skill that involves integration of sensory inputs and the planning and execution of flexible movement patterns. Carrying side packs is famous in our society especially shoulder side packs. Most students carry shoulder side packs and they don't care about the way to carry them to be more balanced. The purpose of the study is to investigate the effect of carrying shoulder side pack on dynamic postural stability and to determine the best way of carrying a shoulder side pack either on the dominant side or non-dominant side that doesn’t affect dynamic postural stability in young healthy female. Methods: Sixty female volunteers aged from 18 to 25 years old participated in the study. Biodex balance system was used to measure the dynamic postural stability in three different occasions (without carrying a shoulder side pack, with carrying a shoulder side pack on the dominant side, and on the non-dominant side with a rest period in between. Results: Repeated measure analysis of variance (ANOVA followed by Bonferroni post hoc test were used to compare dynamic posture balance without carrying and during carrying a shoulder side pack on dominant and non-dominant sides. Analysis revealed that overall, anteroposterior and mediolateral stability indexes reduced significantly (P<0.0001 when carrying shoulder side pack on dominant side in comparison with when carrying shoulder side pack on non-dominant side and without carrying bag. Conclusion: It was concluded that carrying a shoulder side pack on the non-dominant side didn't disturb the postural stability when compared to carrying on the dominant side so, we recommend the students to carry shoulder side packs on the non-dominant side.

  4. The Dynamic Evaluation of Rock Slope Stability Considering the Effects of Microseismic Damage

    Science.gov (United States)

    Xu, N. W.; Dai, F.; Liang, Z. Z.; Zhou, Z.; Sha, C.; Tang, C. A.

    2014-03-01

    A state-of-the-art microseismic monitoring system has been implemented at the left bank slope of the Jinping first stage hydropower station since June 2009. The main objectives are to ensure slope safety under continuous excavation at the left slope, and, very recently, the safety of the concrete arch dam. The safety of the excavated slope is investigated through the development of fast and accurate real-time event location techniques aimed at assessing the evolution and migration of the seismic activity, as well as through the development of prediction capabilities for rock slope instability. Myriads of seismic events at the slope have been recorded by the microseismic monitoring system. Regions of damaged rock mass have been identified and delineated on the basis of the tempo-spatial distribution analysis of microseismic activity during the periods of excavation and consolidation grouting. However, how to effectively utilize the abundant microseismic data in order to quantify the stability of the slope remains a challenge. In this paper, a rock mass damage evolutional model based on microseismic data is proposed, combined with a 3D finite element method (FEM) model for feedback analysis of the left bank slope stability. The model elements with microseismic damage are interrogated and the deteriorated mechanical parameters determined accordingly. The relationship between microseismic activities induced by rock mass damage during slope instability, strength degradation, and dynamic instability of the slope are explored, and the slope stability is quantitatively evaluated. The results indicate that a constitutive relation considering microseismic damage is concordant with the simulation results and the influence of rock mass damage can be allowed for its feedback analysis of 3D slope stability. In addition, the safety coefficient of the rock slope considering microseismic damage is reduced by a value of 0.11, in comparison to the virgin rock slope model. Our results

  5. Induced current in superconducting coils and its effect on dynamic stability

    International Nuclear Information System (INIS)

    Wang Haibin; Zhou Youhe; Zheng Xiaojing

    2003-01-01

    An analysis of the dynamic stability of the superconducting coils in tokamak-type fusion reactor has been performed, when the induced current and its effect on the dynamic stability have been taken into account from the theory of magnetism captured by the superconducting coil. Based on the theory of curved beams and the Biot-Savart law, a theoretical model of the magneto-elastic interactions among the deformation of the coils, the electromagnetic force exerted on the coils and the induced current of the coils has been established. From the numerical analysis of a three-coil superconducting partial torus, it is found that the induced current due to the coil vibration is very small when a steady current is applied in the coil, therefore there is a little effect of the current on the mechanical behavior of the coil. When the structure is subjected to a transient electromagnetic force due to a rapid change of pulse current, the influence of induced current on the mechanical behavior becomes notable. That is to say, the range of magneto-elastic dynamic stability becomes smaller due to the induced current in the superconducting partial torus when pulse current is applied in the coils

  6. Effect of ohmic heating processing conditions on color stability of fungal pigments.

    Science.gov (United States)

    Aguilar-Machado, Diederich; Morales-Oyervides, Lourdes; Contreras-Esquivel, Juan C; Aguilar, Cristóbal; Méndez-Zavala, Alejandro; Raso, Javier; Montañez, Julio

    2017-06-01

    The aim of this work was to analyze the effect of ohmic heating processing conditions on the color stability of a red pigment extract produced by Penicillium purpurogenum GH2 suspended in a buffer solution (pH 6) and in a beverage model system (pH 4). Color stability of pigmented extract was evaluated in the range of 60-90 ℃. The degradation pattern of pigments was well described by the first-order (fractional conversion) and Bigelow model. Degradation rate constants ranged between 0.009 and 0.088 min -1 in systems evaluated. Significant differences in the rate constant values of the ohmic heating-treated samples in comparison with conventional thermal treatment suggested a possible effect of the oscillating electric field generated during ohmic heating. The thermodynamic analysis also indicated differences in the color degradation mechanism during ohmic heating specifically when the pigment was suspended in the beverage model system. In general, red pigments produced by P. purpurogenum GH2 presented good thermal stability under the range of the evaluated experimental conditions, showing potential future applications in pasteurized food matrices using ohmic heating treatment.

  7. Carpal boss: effect of wedge excision depth on third carpometacarpal joint stability.

    Science.gov (United States)

    Vermeulen, G M; de With, M C J; Bleys, R L A W; Schuurman, A H

    2009-01-01

    We hypothesize that carpal-metacarpal (CMC) instability after carpal boss wedge excision is not caused only by damage to the dorsal ligament but mainly depends on the depth of the bony resection. To test our hypothesis, this study analyzes the effect of wedge excisions with different depths (0, 15%, 35%, 55% of the third CMC joint) and the effect of different forces (0, 50, 100 N.m) on the stability (measured as the passive flexion) of the third CMC joint using 12 fresh-frozen human cadaver wrists. The passive flexion is defined as the increase in angular motion of the third CMC joint and represents change in stability during flexion of the joint. The results show that the mean passive flexion measured in the wedge excisions of 15% and 35% of the joint did not differ from that of neutral controls. Joints analyzed after a 55% wedge excision showed a significant increase in angular motion (increased passive flexion). This relates to the 50 N.m as well as the 100 N.m loaded test position. This study shows that a wedge excision of clinically applicable depth of 35% does not create instability during flexion of the third CMC joint when loaded with physiologically relevant forces. Yet an extended and hardly clinically relevant 55% wedge excision results in a change in stability of the joint. To prevent instability when performing a wedge excision for symptomatic carpal boss, care must be taken to avoid excisions that exceed 35% of the third CMC joint.

  8. The effect of unicycle riding course on trunk strength and trunk stability functions in children.

    Science.gov (United States)

    Kocjan, Andrej; Sarabon, Nejc

    2017-07-24

    The aim of the study was to assess the effect of unicycling on trunk strength and timing of automatic stability actions of the selected trunk muscles (multifidus, obliquus externus, erector spine). Twenty healthy 12-year-old children (12 boys, 8 girls; age 12.1 ± 0.2 yrs; body height 1.57 ± 0.05 m; body mass 52.8 ± 10.6 kg) were assigned to experimental and control group. Experimental group performed a supervised 12-session course of unicycling. Trunk strength was measured with a multi-purpose diagnostic machine in frontal and sagittal planes in standing position. Trunk reflex responses and anticipatory actions were assessed through unexpected loading over the hands and rapid shoulder flexion, respectively. After the intervention, strength increased significantly (p muscles (p < 0.001). Anticipatory postural adaptations improved significantly (p < 0.05) in multifidus and obliquus externus of the experimental group only. Unicycling proved to be an effective and funny tool to develop proximal stability and strength, which prevents low back pain and improves the efficiency of energy transfer between body segments. To improve the efficiency of physical education classes, unicycling should be considered a useful tool to increase trunk strength and stability among prepubertal children.

  9. Effects of process conditions on chlorine generation and storage stability of electrolyzed deep ocean water.

    Science.gov (United States)

    Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

    2015-12-01

    Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmentally friendly. We investigated the effects of platinum plating of electrode, electrode size, cell potential, and additional stirring on electrolysis properties of deep ocean water (DOW) and DOW concentration products. We also studied the relationships between quality properties of electrolyzed DOW and their storage stability. Results indicated that concentrating DOW to 1.7 times increased chlorine level in the electrolyzed DOW without affecting electric and current efficiencies of the electrolysis process. Increasing magnesium and potassium levels in DOW decreased chlorine level in the electrolyzed DOW as well as electric and current efficiencies of the electrolysis process. Additional stirring could not increase electrolysis efficiency of small electrolyzer. Large electrode, high electric potential and/or small electrolyzing cell increased chlorine production rate but decreased electric and current efficiencies. High electrolysis intensity decreased storage stability of the electrolyzed seawater and the effects of electrolysis on DOW gradually subsided in storage. DOW has similar electrolysis properties to surface seawater, but its purity and stability are better. Therefore, electrolyzed DOW should have better potential for applications on postharvest cleaning and disinfection of ready-to-eat fresh produce. Copyright © 2015. Published by Elsevier B.V.

  10. Effects of shoulder stabilization exercise on pain and functional recovery of shoulder impingement syndrome patients.

    Science.gov (United States)

    Park, Sang-In; Choi, Yong-Kyu; Lee, Jung-Ho; Kim, Young-Min

    2013-11-01

    [Purpose] This study examined the effects of scapular stabilization exercises immediately after surgery on pain and function in patients diagnosed with shoulder impingement syndrome. [Subjects] The subjects were assigned by random sampling to an experimental group (n=15) to which stabilization exercise was applied and a control group (n=15) to which ordinary physical treatment was applied. [Methods] To evaluate the degree of pain, a 100 mm visual analogue scale (VAS) was used. The Constant-Murley Scale (CMS) was used to evaluate the functions of the shoulder joints. To determine the range of motion, a goniometer was used to measure range of shoulder motion. The simple shoulder test (SST) was used to determine the condition of the shoulder joints of the subjects. [Results] There were significant differences in all the items of the experimental group. The results of comparison of the therapeutic effect in the experimental and control groups revealed significant differences in active abduction, passive abduction, VAS, SST, and the CMS, except for pain. [Conclusion] The results suggest that shoulder stabilization exercise positively affects pain alleviation and functional recovery in shoulder impingement patients.

  11. Rainfall induced stability on the basis of unsaturated effective stress principle for Busan landslide

    Science.gov (United States)

    Oh, Seboong; Achmad Zaky, Fauzi; Ko, Jae Young; Lee, Jaewoo

    2017-04-01

    Heavy rainfall-induced landslide is one of major climatic problems in Korea. This study reports infiltration and stability analyses on both actual failure and non-failure areas. Three out of eight areas in Busan have been recognized to experience actual failure due to prolonged precipitation. Using the stochastic rainfall intensity, the measured hydromechanical properties, and the prescribed initial conditions, the one-dimensional infiltration model assessed the infiltration behavior in unsaturated conditions for 24 hours. To examine the stability of shallow layers, infinite slope model was conducted using generalized effective stress framework based on transient infiltration analysis. The failures could be simulated as time dependent variation of both saturation and pore water pressure, and time dependent reduction of factor of safety into 1.0. It is also shown that the transient infiltration and stability analyses can reconstruct failure events under the generalized effective stress framework. Acknowledgements: This research is supported by grant from Korean NRF (2015R1A2A2A01003933), which are greatly appreciated.

  12. The effects of carrying extra weight on ankle stability in adolescent basketball players.

    Science.gov (United States)

    Ozunlu, Nihan; Basari, Gul Oznur; Baltaci, Gul

    2010-01-01

    The purpose of this study was to investigate the effects of weight on ankle stability in adolescent basketball players. 20 non-injured subjects (age=11.05+/-1.5 years) were included in this study. Each subject performed a 15min warm-up by running or riding a stationary bike. The Star Excursion Balance Test (SEBT), single-leg balance test (performed with eyes open and eyes closed) and vertical jump test were performed with dominant lower extremity. 1 week later, same tests were performed with a schoolbag. The schoolbag contained weight bars as 20% of the players own body weight. Only posteromedial component of SEBT had significant difference between non-weight measurement and weighted measurement (p=0.004). Single-leg stance test performed with eyes open (p=0.006) and closed (p=0.001) had significant difference between non-weight measurement and weighted measurement. Also the vertical jump test had significant difference between non-weight measurement and weighted measurement (p=0.001). These findings indicate that 20% weight of their own body weight does not affect dynamic ankle stability and postural limitations, which are magnified by advancing weight. We are confident in our conclusions because of the three-way interaction noted with posterior/medial with weight in SEBT. Furthermore, Star Excursion Balance test is more effective both weight and non-weight in measuring functional stability of the ankle. Copyright 2010 Elsevier Ltd. All rights reserved.

  13. Investigation of the Effects of Abutment and Implant Length on Stability of Short Dental Implants

    Directory of Open Access Journals (Sweden)

    Eda OZYILMAZ

    2015-01-01

    Full Text Available The use of dental implants to solve different problems in dentistry has been growing rapidly. The success rates of dental implants are also very important for patients. Depending on the bone level of patients, short dental implants are very popular and widely used by many dentists. Although many dentists are using short dental implants frequently, It can be guessed that there can be stability problems because of crown to implant ratios. In this study, it is aimed to find out the effects of dental implant and abutment lengths on stability of short dental implants. 3 different short dental implant design made with the use of Solidworks 2013. Abutment lengths were 3,5 mm, 4 mm, 4,5 mm, 5 mm and implant lengths were 5 mm, 6 mm, 7 mm for each model. Human mandible model is transferred from Computed Tomography. Then, each implant model is mounted to modeled mandible and Finite Element Analysis is performed for each model. In order to see the effects of implant number on stability, we performed same analysis by placing 4 implants to the mandible

  14. Modelling the effect of gas injections on the stability of asphaltene-containing crude oils

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Moorwood, T. [Infochem, Munich (Germany); Merino Garcia, D.; Pena Diez, J.L. [Repsol YPF, Madrid (Spain)

    2008-07-01

    In oil fields where asphaltene deposits occur, they present major remediation problems and can halt production due to flow blockage. Crude oils which precipitate asphaltenes generally contain both asphaltene molecules and lighter resin molecules. Resins are thought to solvate the asphaltene molecules, thus stabilizing the solution, while light gases have the opposite effect. In order to model asphaltene phase behaviour, it is important to understand the impact of adding gas to asphaltene-containing crudes. This study presented several experimental investigations of gas injection into asphaltene-containing crudes. The trends of asphaltene destabilization were discussed. The injection gases ranged from pure gases to a gas condensate. The data were modelled using a conventional equation of state together with an extra term that considered the association between asphaltene molecules and their solvation by resins. Since the model could simultaneously described the gas, oil and asphaltene phases, it was possible to calculate phase stability and phase equilibria. However, a different model had to be used to obtain the gas-oil equilibrium because the use of solubility parameters only allows the stability of the asphaltene phase to be calculated. The model correctly predicted that the gases will promote asphaltene precipitation. In its original form, the model tended to over-predict the trend. The optimal parameter values needed to represent all the available experimental data were determined. The extent to which the effect of gas injection on asphaltenes can be predicted was then discussed.

  15. Effect of okra cell wall and polysaccharide on physical properties and stability of ice cream.

    Science.gov (United States)

    Yuennan, Pilapa; Sajjaanantakul, Tanaboon; Goff, H Douglas

    2014-08-01

    Stabilizers are used in ice cream to increase mix viscosity, promote smooth texture, and improve frozen stability. In this study, the effects of varying concentrations (0.00%, 0.15%, 0.30%, and 0.45%) of okra cell wall (OKW) and its corresponding water-soluble polysaccharide (OKP) on the physical characteristics of ice cream were determined. Ice cream mix viscosity was measured as well as overrun, meltdown, and consumer acceptability. Ice recrystallization was determined after ice cream was subjected to temperature cycling in the range of -10 to -20 °C for 10 cycles. Mix viscosity increased significantly as the concentrations of OKW and OKP increased. The addition of either OKW or OKP at 0.15% to 0.45% significantly improved the melting resistance of ice cream. OKW and OKP at 0.15% did not affect sensory perception score for flavor, texture, and overall liking of the ice cream. OKW and OKP (0.15%) reduced ice crystal growth to 107% and 87%, respectively, as compared to 132% for the control (0.00%). Thus, our results suggested the potential use of OKW and OKP at 0.15% as a stabilizer to control ice cream quality and retard ice recrystallization. OKP, however, at 0.15% exhibited greater effect on viscosity increase and on ice recrystallization inhibition than OKW. © 2014 Institute of Food Technologists®

  16. 3D Microstructure Effects in Ni-YSZ Anodes: Prediction of Effective Transport Properties and Optimization of Redox Stability

    Directory of Open Access Journals (Sweden)

    Omar M. Pecho

    2015-08-01

    Full Text Available This study investigates the influence of microstructure on the effective ionic and electrical conductivities of Ni-YSZ (yttria-stabilized zirconia anodes. Fine, medium, and coarse microstructures are exposed to redox cycling at 950 °C. FIB (focused ion beam-tomography and image analysis are used to quantify the effective (connected volume fraction (Φeff, constriction factor (β, and tortuosity (τ. The effective conductivity (σeff is described as the product of intrinsic conductivity (σ0 and the so-called microstructure-factor (M: σeff = σ0*M. Two different methods are used to evaluate the M-factor: (1 by prediction using a recently established relationship, Mpred = εβ0.36/τ5.17, and (2 by numerical simulation that provides conductivity, from which the simulated M-factor can be deduced (Msim. Both methods give complementary and consistent information about the effective transport properties and the redox degradation mechanism. The initial microstructure has a strong influence on effective conductivities and their degradation. Finer anodes have higher initial conductivities but undergo more intensive Ni coarsening. Coarser anodes have a more stable Ni phase but exhibit lower YSZ stability due to lower sintering activity. Consequently, in order to improve redox stability, it is proposed to use mixtures of fine and coarse powders in different proportions for functional anode and current collector layers.

  17. Effects of different encapsulation agents and drying process on stability of betalains extract.

    Science.gov (United States)

    Ravichandran, Kavitha; Palaniraj, Ravichandran; Saw, Nay Min Min Thaw; Gabr, Ahmed M M; Ahmed, Abdelrahman R; Knorr, Dietrich; Smetanska, Iryna

    2014-09-01

    Red beet plants are rich in betalains that can be used as food natural colorants. Betalains were extracted from red beet and encapsulated with different carrier agents and freeze or spray dried. Effect of different encapsulating agents as maltodextrin, guar gum, gum Arabic, pectin and xanthan gum with different concentration (as encapsulating agents) were studied on the betalain stability. Encapsulated betalains with xanthan gum with maltodextrin showed about 65 % more recovery than the control. Encapsulation showed a higher recovery of betalains during freeze drying by 1.3 times than during spray drying. Spray dried samples has L* (lightness) higher than the freeze dried samples. The variations of maltodextrin with xanthan and guar gum freeze dried have highest chroma value of 21. The stabilization of pure betalain pigments may boost the use of these colouring molecules in the food industry and promote their application.

  18. Finite ion velocity effects on the stability of Pierce-like diodes

    International Nuclear Information System (INIS)

    Kolinsky, H.; Schamel, H.

    1994-01-01

    The stability of Pierce-like plasma diodes is investigated for arbitrary ion injection velocities. A recently developed integral formalism that accounts for ion dynamical effects is applied to derive a generalized dispersion relation for electrostatic perturbations. Its evaluation exhibits several new features, such as the appearance of growing oscillatory modes, which become Pierce--Buneman modes in the limit of initially resting ions, and of weakly damped oscillatory modes, which become undamped ion plasma oscillations in this limit. The stability of this bounded plasma system is shown to be controlled by the new control parameter at signga=α(1+at signgm) 1/2 , where α is the Pierce parameter and at signgm≡m ev 2 e0 /m iv 2 i0 the ratio of electron and ion kinetic energy at the emitter

  19. Effect of van der Waals interactions on the stability of SiC polytypes

    Energy Technology Data Exchange (ETDEWEB)

    Kawanishi, Sakiko, E-mail: s-kawa@tagen.tohoku.ac.jp; Mizoguchi, Teruyasu [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

    2016-05-07

    Density functional theory calculations with a correction of the long-range dispersion force, namely, the van der Waals (vdW) force, are performed for SiC polytypes. The lattice parameters are in good agreement with those obtained from the experiments. Furthermore, the stability of the polytypes in the experiments, which show 3C-SiC as the most stable, is reproduced by the present calculations. The effects of the vdW force on the electronic structure and the stability of polytypes are discussed. We observe that the vdW interaction is more sensitive to the cubic site than the hexagonal site. Thus, the influence of the vdW force increases with decreasing the hexagonality of the polytype, which results in the confirmation that the most stable polytype is 3C-SiC.

  20. Effects of PEG size on structure, function and stability of PEGylated BSA

    DEFF Research Database (Denmark)

    Plesner, Bitten; Fee, Conan J.; Westh, Peter

    2011-01-01

    The effects of PEGylation on the structural, thermal and functional stability of bovine serum albumin (BSA) were investigated using BSA and 6 linear mono-PEGylated BSA compounds. The secondary and tertiary structure of BSA measured by circular dichroism (CD) was independent of PEGylation....... In contrast, the thermal stability of BSA was affected by PEGylation. The apparent unfolding temperature Tmax measured by differential scanning calorimetry (DSC) decreased with PEGylation, whereas the temperature of aggregation, Tagg, measured by dynamic light scattering (DLS) increased with PEGylation....... The unfolding temperature and the temperature of aggregation were both independent of the molecular weight of the PEG chain. Possible functional changes of BSA after PEGylation were measured by Isothermal Titration Calorimetry (ITC), where the binding of sodium dodecyl sulphate (SDS) to BSA and PEGylated BSA...

  1. Effects of sodium diacetate on the fermentation profile, chemical composition and aerobic stability of alfalfa silage

    Science.gov (United States)

    Yuan, XianJun; Wen, AiYou; Desta, Seare T.; Wang, Jian; Shao, Tao

    2017-01-01

    Objective The objective of this study was to evaluate the effect of sodium diacetate (SDA) on fermentation profile, chemical composition and aerobic stability of alfalfa (Medicago sativa L.) silage. Methods Fresh alfalfa was ensiled with various concentrations of SDA (0, 3, 5, 7, and 9 g/kg of fresh forage). After 60 days of the ensiling, the samples were collected to examine the fermentative quality, chemical composition and aerobic stability. Results The application of SDA significantly (pensiling. Alfalfa silages treated with SDA at 7 g/kg had highest Flieg’s point and remained stable more than 9 d during aerobic exposure under humid and hot conditions in southern China. Conclusion SDA may be used as an additive for alfalfa silages at a level of 7 g/kg. PMID:28111451

  2. Effect of a cathode buffer layer on the stability of organic solar cells

    International Nuclear Information System (INIS)

    Wang, Danbei; Zeng, Wenjin; Chen, Shilin; Su, Xiaodan; Wang, Jin; Zhang, Hongmei

    2015-01-01

    We present the effect of a cathode buffer layer on the performance and stability of organic photovoltaics (OPVs) based on a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Six kinds of cathode buffer layers, i.e. lithium fluoride, sodium chloride, NaCl/Mg, tris-(8-hydroxy-quinoline) aluminum, bathocuproine and 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene, were inserted between the photoactive layer and an Al cathode, which played a dominant role in the device’s performance. Devices with the cathode buffer layers above exhibited improved performance. The degradation of these devices with encapsulation was further investigated in an inert atmosphere. The results indicated that devices with inorganic cathode buffer layers exhibited better stability than those with organic cathode buffer layers. (paper)

  3. Radial effects in heating and thermal stability of a sub-ignited tokamak

    International Nuclear Information System (INIS)

    Fuchs, V.; Shoucri, M.M.; Thibaudeau, G.; Harten, L.; Bers, A.

    1982-02-01

    The existence of thermally stable sub-ignited equilibria of a tokamak reactor, sustained in operation by a feedback-controlled supplementary heating source, is demonstrated. The establishment of stability depends on a number of radially non-uniform, nonlinear processes whose effect is analyzed. One-dimensional (radial) stability analyses of model transport equations, together with numerical results from a 1-D transport code, are used in studying the heating of DT-plasmas in the thermonuclear regime. Plasma core supplementary heating is found to be a thermally more stable process than bulk heating. In the presence of impurity line radiation, however, core-heated temperature profiles may collapse, contracting inward from the limiter, the result of an instability caused by the increasing nature of the radiative cooling rate, with decreasing temperature. Conditions are established for the realization of a sub-ignited high-Q, toroidal reactor plasma with appreciable output power

  4. Effect of base media on the stability of annatto dye in industrial products

    International Nuclear Information System (INIS)

    Audetuyi, A.O.; Lajide, L.; Popoola, A.V.

    2006-01-01

    Colour stability of the versatile annatto dye was examined to monitor the effects of base media on industrial products. The dye was incorporated in two media, namely, palm kernel oil used in products such as body cream and soap, and paraffin wax used in shoe polish and household candle wax. These products were exposed to various light conditions for a specific period before assessment. The melting point of the dye was determined as 176-178 degree C with a molar absorptivity of 13,600 mol/sub -1/ cm/sub -1/ at 545 nm. It imparted its brilliant yellow/orange colouration in industrial products as the colour stability depends on the compounding base media of the products. Losses of beta-carotene was higher and faster in nonaqueous environment as paraffin wax showed low fastness rating values, than in the palm kernel oil based aqueous medium products. (author)

  5. In vitro cytotoxicity of iron oxide nanoparticles: effects of chitosan and polyvinyl alcohol as stabilizing agents

    Science.gov (United States)

    Tran, Phong A.; Nguyen, Hiep T.; Fox, Kate; Tran, Nhiem

    2018-03-01

    Iron oxide magnetic nanoparticles have significant potential in biomedical applications such as in diagnosis, imaging and therapeutic agent delivery. The choice of stabilizers and surface functionalization is important as it is known to strongly influence the cytotoxicity of the nanoparticles. The present study aimed at investigating the effects of surface charges on the cytotoxicity of iron oxide nanoparticles. We used a co-precipitation method to synthesize iron oxide nanoparticles which were then stabilized with either chitosan (CS) or polyvinyl alcohol (PVA) which have net positive charge and zero charge at physiological pH, respectively. The nanoparticles were characterized in terms of size, charges and chemical oxidation state. Cytotoxicity of the nanoparticles was assessed using mouse fibroblast cells and was correlated with surface charges of the nanoparticles and their aggregation.

  6. Dual-tasking effects on dynamic postural stability in athletes with and without anterior cruciate ligament reconstruction

    NARCIS (Netherlands)

    Mohammadi-Rad, Shahrzad; Salavati, Mahyar; Ebrahimi-Takamjani, Ismail; Akhbari, Behnam; Sherafat, Shiva; Negahban, Hossein; Lali, Pezhman; Mazaheri, Masood

    2016-01-01

    Purpose: To compare the effect of dual tasking on postural stability between patients with anterior cruciate ligament reconstruction (ACL-R) and healthy controls. Methods: Single-limb postural stability was assessed in 17 athletes with ACL-R and 17 healthy matched athletes while standing on a Biodex

  7. Evaluation of nutritional and chemical composition of yacon syrup using 1H NMR and UPLC-ESI-Q-TOF-MSE.

    Science.gov (United States)

    Silva, Maria de Fátima Gomes da; Dionísio, Ana Paula; Abreu, Fernando Antonio Pinto de; Brito, Edy Sousa de; Wurlitzer, Nedio Jair; Silva, Lorena Mara Alexandre E; Ribeiro, Paulo Riceli Vasconcelos; Rodrigues, Sueli; Taniguchi, Carlos Alberto Kenji; Pontes, Dorasilvia Ferreira

    2018-04-15

    A complete characterization of yacon syrup was performed by analytical techniques, including NMR and UPLC-QTOF-MS E . The effect of the different stages of yacon syrup production on fructooligosaccharides (FOS) and chlorogenic acid (CGA) contents were also evaluated. As a result, in addition to higher levels of FOS and CGA, some mineral elements, such as K, Ca and P, and essential amino acids, such as tryptophan, valine, and threonine, were determined in yacon syrup. Twenty-five compounds were putatively identified, and the main compounds were phenolics derived from quinic and trans-cinnamic acids. Considering the different stages of yacon syrup production, the results indicate that the contents of FOS and CGA were maintained in the pulping, enzymatic maceration and microfiltration, leading to a concentration of these components in the last stage of processing (vacuum concentration). These results will be used to fortify this innovative and promising product in the area of functional foods. Copyright © 2017. Published by Elsevier Ltd.

  8. Effect of thermal protectants on the stability of bovine milk immunoglobulin G

    International Nuclear Information System (INIS)

    Chen, C.C.; Chang, H.M.

    1998-01-01

    pH stability, thermal stability, and the effect of homogenization and ultrasonic treatment on the stability of bovine milk immunoglobulin G (IgG) in model systems was studied. Separated IgG (0.02 mg/mL) was found to be unstable and susceptible to denaturation when incubated at pH 4 or 10 or thermally treated at temperature 75 degrees C. IgG in the colostrum, on the other hand, was found to be much more stable than in whey or in PBS when thermally treated at temperatures in the range of 75-100 degrees C. The residual IgC content reduced more sharply with increasing heating times, and almost no IgG content was detected when IgG in PBS (0.15 M NaCl/0.01 M phosphate buffer, pH 7.0) was heated at 95 degrees C for 15 s, whereas the corresponding residual IgG contents in whey and colostrum were found to be 42 and 59%, respectively. For IgG in PBS heated at 95 degrees C for 15 s, addition of 5% fructose or maltose displayed most remarkable protection effects by raising the residual IgG content to 31%, followed by sucrose, lactose, glucose, and galactose. However, extravagant addition ( 30%) to IgG in PBS led to a decline in residual IgG content. Addition of 0.4% glutamic acid and 2% glycine to IgG in PBS heated at 95 degrees C for 15 s also remarkably improved the residual IgG content by 13.5 and 26.7%, respectively. Glycerol and sugar alcohol, such as sorbitol, stabilized IgG during the thermal treatment

  9. Effectiveness of Conventional Rehabilitation Therapy on Postural Stability and Clinic in Stroke Patients with Hemiplegia

    Directory of Open Access Journals (Sweden)

    Ahmet Inanir

    2013-06-01

    Full Text Available Objective: The aim of the present study was to determine the effectiviness of conventional rehabilitation in patients with stroke on static and dynamic balance as well as clinical assessment Methods: Twelve patients with stroke, 7 (58.33% of them being male and 5 (41.66% female, ranging from 51 to 75 in age who were treated in Physical Medicine and Rehabilitation clinic were involved in this study. The patients were treated with conventional rehabilitation. All individuals were evaluated using balance tests before (Group 1 and after (Group 2 the treatment. Balance level and postural control has been assessed through Berg Balance Scale (BBS, Trunk Control Test (TCT and Biodex Stability System (BSS, motor level through BMIE, ambulation state through Functional Ambulatory Scale (FAS and functional state in daily activities through Functional Independence Measure (FIM. The same tests were repeated while the patients were being discharged. Results: The mean age of the study population was 65,83±4,38 years, the average Body Mas Index (BMI was 30,55±6,94. In the evaluations according to FIM, FAS, TCT and BBS differences between the mean of patients before and after the rehabilitation were significantly higher for the post-treatment (p=0.001, p=0.001, p=0.001 and p=0.001, respectively. In the evaluations according to Overall Stability Index (OSI, Antero-Posterior Stability Index (APSI and Medio-Lateral Stability Index (MLSI differences between the mean of patients before and after the rehabilitation were significantly higher for the pre-treatment (p=0.001, p=0.001 and p=0.001, respectively. Conclusion: It can be stated that this approach is effective and useful in restoring static and dynamic balance as well as in obtaining an effective improvement in the treatment of patients with stroke through conventional treatment. [Cukurova Med J 2013; 38(3.000: 446-455

  10. Strong Stability Preserving Explicit Runge--Kutta Methods of Maximal Effective Order

    KAUST Repository

    Hadjimichael, Yiannis

    2013-07-23

    We apply the concept of effective order to strong stability preserving (SSP) explicit Runge--Kutta methods. Relative to classical Runge--Kutta methods, methods with an effective order of accuracy are designed to satisfy a relaxed set of order conditions but yield higher order accuracy when composed with special starting and stopping methods. We show that this allows the construction of four-stage SSP methods with effective order four (such methods cannot have classical order four). However, we also prove that effective order five methods---like classical order five methods---require the use of nonpositive weights and so cannot be SSP. By numerical optimization, we construct explicit SSP Runge--Kutta methods up to effective order four and establish the optimality of many of them. Numerical experiments demonstrate the validity of these methods in practice.

  11. The effects of temperature on the formation and stability of bipolarons in conjugated polymers

    Science.gov (United States)

    Meng, Yan; Guo, Guang-jie; Wang, Ya-dong; Li, Yin-feng; An, Zhong

    2017-04-01

    Within the one-dimensional tight-binding Su-Schrieffer-Heeger (SSH) model modified to include thermal effects and electron-electron interactions, the transition from polaron to bipolaron and the formation of bipolaron induced by injecting charges are separately simulated using a nonadiabatic evolution method. For the transition process, it is found that with the temperature effects taken into account, two separate polarons with the same charge and antiparallel spins can recombine into a bipolaron. The results show that with the temperature increasing, the time taken for the recombination of two polarons decreases. The effects of different distances between the polarons are also numerically simulated. For the bipolaron formation, we investigate the evolution of two charges injected into a polymer chain with the thermal effects. We find that the bipolaron is always quickly formed and its dynamical stability is less sensitive to the temperature change. Thermal effects can only affect the degree of the charges localization.

  12. Effect of meniscus replacement fixation technique on restoration of knee contact mechanics and stability.

    Science.gov (United States)

    D'Lima, D D; Chen, P C; Kessler, O; Hoenecke, H R; Colwell, C W

    2011-06-01

    The menisci are important biomechanical components of the knee. We developed and validated a finite element model of meniscal replacement to assess the effect of surgical fixation technique on contact behavior and knee stability. The geometry of femoral and tibial articular cartilage and menisci was segmented from magnetic resonance images of a normal cadaver knee using MIMICS (Materialise, Leuven, Belgium). A finite element mesh was generated using HyperWorks (Altair Inc, Santa Ana, CA). A finite element solver (Abaqus v6.9, Simulia, Providence, RI) was used to compute contact area and stresses under axial loading and to assess stability (reaction force generated during anteroposterior translation of the femur). The natural and surgical attachments of the meniscal horns and peripheral rim were simulated using springs. After total meniscectomy, femoral contact area decreased by 26% with a concomitant increase in average contact stresses (36%) and peak contact stresses (33%). Replacing the meniscus without suturing the horns did little to restore femoral contact area. Suturing the horns increased contact area and reduced peak contact stresses. Increasing suture stiffness correlated with increased meniscal contact stresses as a greater proportion of tibiofemoral load was transferred to the meniscus. A small incremental benefit was seen of simulated bone plug fixation over the suture construct with the highest stiffness (50 N/mm). Suturing the rim did little to change contact conditions. The nominal anteroposterior stiffness reduced by 3.1 N/mm after meniscectomy. In contrast to contact area and stress, stiffness of the horn fixation sutures had a smaller effect on anteroposterior stability. On the other hand suturing the rim of the meniscus affected anteroposterior stability to a much larger degree. This model emphasizes the importance of the meniscus in knee biomechanics. Appropriate meniscal replacement fixation techniques are likely to be critical to the clinical

  13. Effects of monohydric alcohols and polyols on the thermal stability of a protein

    Science.gov (United States)

    Murakami, Shota; Kinoshita, Masahiro

    2016-03-01

    The thermal stability of a protein is lowered by the addition of a monohydric alcohol, and this effect becomes larger as the size of hydrophobic group in an alcohol molecule increases. By contrast, it is enhanced by the addition of a polyol possessing two or more hydroxyl groups per molecule, and this effect becomes larger as the number of hydroxyl groups increases. Here, we show that all of these experimental observations can be reproduced even in a quantitative sense by rigid-body models focused on the entropic effect originating from the translational displacement of solvent molecules. The solvent is either pure water or water-cosolvent solution. Three monohydric alcohols and five polyols are considered as cosolvents. In the rigid-body models, a protein is a fused hard spheres accounting for the polyatomic structure in the atomic detail, and the solvent is formed by hard spheres or a binary mixture of hard spheres with different diameters. The effective diameter of cosolvent molecules and the packing fractions of water and cosolvent, which are crucially important parameters, are carefully estimated using the experimental data of properties such as the density of solid crystal of cosolvent, parameters in the pertinent cosolvent-cosolvent interaction potential, and density of water-cosolvent solution. We employ the morphometric approach combined with the integral equation theory, which is best suited to the physical interpretation of the calculation result. It is argued that the degree of solvent crowding in the bulk is the key factor. When it is made more serious by the cosolvent addition, the solvent-entropy gain upon protein folding is magnified, leading to the enhanced thermal stability. When it is made less serious, the opposite is true. The mechanism of the effects of monohydric alcohols and polyols is physically the same as that of sugars. However, when the rigid-body models are employed for the effect of urea, its addition is predicted to enhance the

  14. Effect of ultrasonic waves on the stability of all-trans lutein and its degradation kinetics.

    Science.gov (United States)

    Song, Jiang-Feng; Li, Da-Jing; Pang, Hui-Li; Liu, Chun-Quan

    2015-11-01

    Ultrasound treatment has been widely applied in the extraction of biologically active compounds including carotenoids. However, there are few reports on their effects on the stability of these compounds. In the present study, the stability of all-trans lutein, one of the carotenoids, was investigated under the action of ultrasound. Results showed that ultrasound induced the isomerization of all-trans lutein to its isomers, namely to 13-cis lutein, 13'-cis lutein, 9-cis lutein and 9'-cis lutein as analyzed by HPLC coupled with DAD and LC-MS; and the percentage of the isomerization increased with increasing both ultrasonic frequency and power. The stability of all-trans lutein in dichloromethane was worst among multiple kinds of solvents. Interestingly, the retention rate of all-trans lutein improved as the temperature increased, which runs counter to the Arrhenius law. Under ultrasound irradiation, the degradation mechanism might be different with various temperatures, the degradation of all-trans lutein followed first-order kinetics at 20°C, while second-order kinetics was followed at 30-50°C. As the ultrasonic reaction time prolonged, lutein epoxidation nearly occurred. Those results presented here emphasized that UAE techniques should be carefully used in the extraction of all-trans lutein. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Thermal-hydraulics stability of natural circulation BWR under startup. Flashing effects

    International Nuclear Information System (INIS)

    Hu, Rui; Kazimi, Mujid S.

    2009-01-01

    To help achieve the necessary natural circulation flow, a fairly long chimney is installed in a boiling natural circulation reactor like the ESBWR. In such systems, thermal-hydraulic stability during low pressure start-up should be examined while considering the flashing induced by the pressure drop in the channel and the chimney due to gravity head. In this work, a BWR stability analysis code in the frequency domain, named FISTAB (Flashing-Induced STability Analysis for BWR), was developed to address the issue of flashing-induced instability. A thermal-hydraulics non-homogeneous equilibrium model (NHEM) based on a drift flux formulation along with a lumped fuel dynamics model is incorporated in the work. The vapor generation rate is derived from the mixture energy conservation equation while considering the effect of flashing. The functionality of the FISTAB code was confirmed by comparison to experimental results from SIRIUS-N facility at CRIEPI, Japan. Both stationary and perturbation results agree well with the experimental results. (author)

  16. The effect of high pressures on the yoghurt from milk with the stabilizer

    International Nuclear Information System (INIS)

    Reps, A; Jankowska, A; Wisniewska, K

    2008-01-01

    The effect of high pressures on the microbiological and physio-chemical properties of yoghurt was investigated. The best results were obtained when the yoghurt was manufactured from milk with the addition of MYO 752 stabilizer (starch, gelatin, pectin) selected from 10 stabilizers. Yoghurt manufactured with the addition of 0, 6% MYO 752 stabilizer was processed at the pressure of 400-600 MPa/15 min. in the range of 50 MPa. Pressurization caused a total reduction of number of Lactobacillus delbrueckii ssp. Bulgaricus and reduced the number of Streptococcus thermophilus by 1-2 orders of magnitude. Pressurized and non-pressurized yoghurts characterized of a homogenous consistency and typical plain yoghurt taste. The decrease of the number of living bacteria was observed in yoghurts during the storage. The acidity of pressurized yoghurts remained on the some level at the temperature of 4 0 C and 20 0 C. The more intensive antibacterial activity of microflora was observed in yoghurts storaged at 20 0 C in comparison with yoghurts storaged at 4 0 C. Disadvantageous changes of the pressurized yoghurts consistency were not found. The taste and aroma of yoghurts remained without any changes

  17. Effects of Sulfate, Chloride, and Bicarbonate on Iron Stability in a PVC-U Drinking Pipe.

    Science.gov (United States)

    Wang, Jiaying; Tao, Tao; Yan, Hexiang

    2017-06-19

    In order to describe iron stability in plastic pipes and to ensure the drinking water security, the influence factors and rules for iron adsorption and release were studied, dependent on the Unplasticized poly (vinyl chloride) (PVC-U) drinking pipes employed in this research. In this paper, sulfate, chloride, and bicarbonate, as well as synthesized models, were chosen to investigate the iron stability on the inner wall of PVC-U drinking pipes. The existence of the three kinds of anions could significantly affect the process of iron adsorption, and a positive association was found between the level of anion concentration and the adsorption rate. However, the scaling formed on the inner surface of the pipes would be released into the water under certain conditions. The Larson Index (LI), used for a synthetic consideration of anion effects on iron stability, was selected to investigate the iron release under multi-factor conditions. Moreover, a well fitted linear model was established to gain a better understanding of iron release under multi-factor conditions. The simulation results demonstrated that the linear model was better fitted than the LI model for the prediction of iron release.

  18. The effect of tooth loss on gait stability of community-dwelling older adults.

    Science.gov (United States)

    Brand, Christina; Bridenbaugh, Stephanie A; Perkovac, Mateja; Glenz, Fabienne; Besimo, Christian E; Sendi, Pedram; Kressig, Reto W; Marinello, Carlo P

    2015-12-01

    To investigate the effects of tooth loss on gait stability in a healthy elderly population. A case-control study was conducted among healthy and prosthetically well-restored seniors over the age of 65 years. The test group comprised 24 edentulous participants who were restored with complete dentures in the upper jaw and an overdenture fixed on two implants in the lower jaw. The control group comprised 25 dentate participants who either still had their natural teeth or were restored with conventional fixed partial dentures. Gait stability was evaluated by measuring the parameters 'gait velocity' and 'cycle-time variability' during self-selected normal walking speed and under dual-task performance conditions. Measurements were conducted using the GAITRite(®) electronic walkway system. Dentated and fixed restored participants (the control group) had a significantly higher gait velocity compared with denture wearers (the test group) under both normal walking (p = 0.03) and dual-task performance conditions (p = 0.01). In each test condition, among edentulous participants, gait velocity did not significantly differ according to whether the participant wore their dentures. The present results suggest that tooth loss in healthy seniors is associated with lower gait velocity and therefore may have a negative impact on gait stability. © 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

  19. Effect of extraction process on composition, oxidative stability and rheological properties of purslane seed oil.

    Science.gov (United States)

    Delfan-Hosseini, Sasan; Nayebzadeh, Kooshan; Mirmoghtadaie, Leila; Kavosi, Maryam; Hosseini, Seyede Marzieh

    2017-05-01

    Purslane seed oil could be considered as potential nutritious oil due to its desirable fatty acid composition and other biological active compounds. In this study the effect of three extraction procedure including solvent extraction, cold pressing and microwave pretreatment (MW) followed by cold pressing on oil yield, physicochemical properties, oxidative stability and rheological behaviors of oil was investigated. Solvent extracted oil had the highest extraction yield (72.31%). Pretreatment by microwave before cold press extraction resulted in an increase in extraction yield, total phenolic compound (TPC) and antioxidant activity. Cold press extracted oil had the lowest oxidative stability (4.64h). This property was greatly enhanced by microwave irradiation, so that the longest oxidative stability was found in MW-cold press extracted oil with 9.67h. Furthermore, all extracted oils demonstrated Newtonian flow behaviors. MW-cold press extracted oil had the greatest apparent viscosity and highest sensitivity to temperature changes (E a =29.18kJ/mol -1 ). Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. The effect of high pressures on the yoghurt from milk with the stabilizer

    Science.gov (United States)

    Reps, A.; Jankowska, A.; Wiśniewska, K.

    2008-07-01

    The effect of high pressures on the microbiological and physio-chemical properties of yoghurt was investigated. The best results were obtained when the yoghurt was manufactured from milk with the addition of MYO 752 stabilizer (starch, gelatin, pectin) selected from 10 stabilizers. Yoghurt manufactured with the addition of 0, 6% MYO 752 stabilizer was processed at the pressure of 400-600 MPa/15 min. in the range of 50 MPa. Pressurization caused a total reduction of number of Lactobacillus delbrueckii ssp. Bulgaricus and reduced the number of Streptococcus thermophilus by 1-2 orders of magnitude. Pressurized and non-pressurized yoghurts characterized of a homogenous consistency and typical plain yoghurt taste. The decrease of the number of living bacteria was observed in yoghurts during the storage. The acidity of pressurized yoghurts remained on the some level at the temperature of 4°C and 20°C. The more intensive antibacterial activity of microflora was observed in yoghurts storaged at 20°C in comparison with yoghurts storaged at 4°C. Disadvantageous changes of the pressurized yoghurts consistency were not found. The taste and aroma of yoghurts remained without any changes.

  1. The effect of high pressures on the yoghurt from milk with the stabilizer

    Energy Technology Data Exchange (ETDEWEB)

    Reps, A; Jankowska, A; Wisniewska, K [Chair of Food Biotechnology, University of Warmia and Mazury, Heweliusza str 1., 10-724 Olsztyn (Poland)], E-mail: arnold.reps@uwm.edu.pl

    2008-07-15

    The effect of high pressures on the microbiological and physio-chemical properties of yoghurt was investigated. The best results were obtained when the yoghurt was manufactured from milk with the addition of MYO 752 stabilizer (starch, gelatin, pectin) selected from 10 stabilizers. Yoghurt manufactured with the addition of 0, 6% MYO 752 stabilizer was processed at the pressure of 400-600 MPa/15 min. in the range of 50 MPa. Pressurization caused a total reduction of number of Lactobacillus delbrueckii ssp. Bulgaricus and reduced the number of Streptococcus thermophilus by 1-2 orders of magnitude. Pressurized and non-pressurized yoghurts characterized of a homogenous consistency and typical plain yoghurt taste. The decrease of the number of living bacteria was observed in yoghurts during the storage. The acidity of pressurized yoghurts remained on the some level at the temperature of 4{sup 0}C and 20{sup 0}C. The more intensive antibacterial activity of microflora was observed in yoghurts storaged at 20{sup 0}C in comparison with yoghurts storaged at 4{sup 0}C. Disadvantageous changes of the pressurized yoghurts consistency were not found. The taste and aroma of yoghurts remained without any changes.

  2. Effect of adding natural pozzolana on geotechnical properties of lime-stabilized clayey soil

    Directory of Open Access Journals (Sweden)

    Aref al-Swaidani

    2016-10-01

    Full Text Available Clayey soils in Syria cover a total area of more than 20,000 km2 of the country, most of which are located in the southwestern region. In many places of the country, the clayey soils caused severe damage to infrastructures. Extensive studies have been carried out on the stabilization of clayey soils using lime. Syria is rich in both lime and natural pozzolana. However, few works have been conducted to investigate the influence of adding natural pozzolana on the geotechnical properties of lime-treated clayey soils. The aim of this paper is to understand the effect of adding natural pozzolana on some geotechnical properties of lime-stabilized clayey soils. Natural pozzolana and lime are added to soil within the range of 0%–20% and 0%–8%, respectively. Consistency, compaction, California bearing ratio (CBR and linear shrinkage properties are particularly investigated. The test results show that the investigated properties of lime-treated clayey soils can be considerably enhanced when the natural pozzolana is added as a stabilizing agent. Analysis results of scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDX show significant changes in the microstructure of the treated clayey soil. A better flocculation of clayey particles and further formation of cementing materials in the natural pozzolana-lime-treated clayey soil are clearly observed.

  3. Effects of plasma shape and profiles on edge stability in DIII-D

    International Nuclear Information System (INIS)

    Lao, L.L.; Ferron, J.R.; Miller, R.L.

    2001-01-01

    The results of recent experimental and theoretical studies concerning the effects of plasma shape and current and pressure profiles on edge instabilities in DIII-D are presented. Magnetic oscillations with toroidal mode number n∼2-9 and a fast growth time γ -1 =20-150μs are often observed prior to the first giant type I ELM in discharges with moderate squareness. High n ideal ballooning second stability access encourages edge instabilities by facilitating the buildup of the edge pressure gradient and bootstrap current density which destabilize the intermediate to low n modes. Analysis suggests that discharges with large edge pressure gradient and bootstrap current density are more unstable to n>1 modes. Calculations and experimental results show that ELM amplitude and frequency can be varied by controlling access to the second ballooning stability regime at the edge through variation of the squareness of the discharge shape. A new method is proposed to control edge instabilities by reducing access to the second ballooning stability regime at the edge using high order local perturbation of the plasma shape in the outboard bad curvature region. (author)

  4. Effects of plasma shape and profiles on edge stability in DIII-D

    International Nuclear Information System (INIS)

    Lao, L.L.; Chan, V.S.; Chen, L.

    1998-12-01

    The results of recent experimental and theoretical studies concerning the effects of plasma shape and current and pressure profiles on edge instabilities in DIII-D are presented. Magnetic oscillations with toroidal mode number n ∼ 2--9 and a fast growth time γ -1 = 20--150 micros are often observed prior to the first giant type 1 ELM in discharges with moderate squareness. High n ideal ballooning second stability access encourages edge instabilities by facilitating the buildup of the edge pressure gradient and bootstrap current density which destabilize the intermediate to low n modes. Analysis suggests that discharges with large edge pressure gradient and bootstrap current density are more unstable to n > 1 modes. Calculations and experimental results show that ELM amplitude and frequency can be varied by controlling access to the second ballooning stability regime at the edge through variation of the squareness of the discharge shape. A new method is proposed to control edge instabilities by reducing access to the second ballooning stability regime at the edge using high order local perturbation of the plasma shape in the outboard bad curvature region

  5. Effects of the Electronic Doping In the Stability of the Metal Hydride NaH

    Science.gov (United States)

    Olea-Amezcua, Monica-Araceli; Rivas-Silva, Juan-Francisco; de La Peña-Seaman, Omar; Heid, Rolf; Bohnen, Klaus-Peter

    2015-03-01

    Despite metal hydrides light weight and high hydrogen volumetric densities, the Hydrogen desorption process requires excessively high temperatures due to their high stability. Attempts for improvement the hydrogenation properties have been focus on the introduction of defects, impurities and doping on the metal hydride. We present a systematic study of the electronic doping effects on the stability of a model system, NaH doped with magnesium, forming the alloying system Na1-xMgxH. We use the density functional theory (DFT) and the self-consistent version of the virtual crystal approximation (VCA) to model the doping of NaH with Mg. The evolution of the ground state structural and electronic properties is analyzed as a function of Mg-content. The full-phonon dispersion, calculated by the linear response theory (LRT) and density functional perturbation theory (DFPT), is analyzed for several Mg-concentrations, paying special attention to the crystal stability and the correlations with the electronic structure. Applying the quasiharmonic approximation (QHA), the free energy from zero-point motion is obtained, and its influence on the properties under study is analyzed. This work is partially supported by the VIEP-BUAP (OMPS-EXC14-I) and CONACYT-Mexico (No. 221807) projects.

  6. Dispersibility and emulsion-stabilizing effect of cellulose nanowhiskers esterified by vinyl acetate and vinyl cinnamate.

    Science.gov (United States)

    Sèbe, Gilles; Ham-Pichavant, Frédérique; Pecastaings, Gilles

    2013-08-12

    The surface of cotton cellulose nanowhiskers (CNW's) was esterified by vinyl acetate (VAc) and vinyl cinnamate (VCin), in the presence of potassium carbonate as catalyst. Reactions were performed under microwave activation and monitored by Fourier transform infrared (FT-IR) spectroscopy. The supramolecular structure of CNW's before and after modification was characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). Distinctively from the acetylation treatment, an increase in particles dimensions was noted after esterification with VCin, which was assigned to π-π stacking interactions that may exist between cinnamoyl moieties. The dispersibility and emulsion stabilizing effect of acylated CNW's was examined in ethyl acetate, toluene, and cyclohexane, three organic solvents of medium to low polarity. The acylated nanoparticles could never be dispersed in toluene nor cyclohexane, but they formed stable dispersions in ethyl acetate while remaining dispersible in water. Stable ethyl acetate-in-water, toluene-in-water, and cyclohexane-in-water emulsions were successfully prepared with CNW's grafted with acetyl moieties, whereas the VCin-treated particles could stabilize only the cyclohexane-in-water emulsions. The impact of esterification treatment on emulsion stability and droplets size was particularly discussed.

  7. Effect of nightguard vital bleaching gel on the color stability of provisional restorative materials.

    Science.gov (United States)

    Bajunaid, Salwa Omar

    2016-01-01

    To assess the hypothesis that there was no difference in effect of 10% and 15% tooth bleaching agents on color stability of materials used for provisional fixed dental prosthesis. Fifteen samples from two materials used for provisional fixed dental prosthesis: methacrylate-based and composite-based materials and 15 preformed polycarbonate crowns soaked in bleaching gel or distilled water. Spectrophotometer recorded color of specimens at baseline, after 3, 7, and 14 days. Data were statistically analyzed using two-factor ANOVA test to compare the color stability of tested materials. Methyl-based provisional material exhibited statistically higher color change when exposed to 10% and 15% bleaching gel (delta EFNx01: 9.0 and 11.1, respectively) as compared to distilled water (delta EFNx01: 2.9). Delta EFNx01 of composite-based material specimens exposed to distilled water was statistically higher (6.3) than specimens exposed to 10% and 15% bleaching gel (1.5 and 1.1, respectively). Polycarbonate crowns showed a statistically lower color change when exposed to 15% (0.9) than to 10% bleaching gel (5.1) or distilled water (5.5). Composite-based provisional material showed highest color stability when exposed to vital tooth bleaching gel, whereas methacrylate-based material was the least color stable. Polycarbonate crowns were more color stable when exposed to 15% bleaching gel as opposed to 10% bleaching gel.

  8. Effects of rapid maxillary expansion on head posture, postural stability, and fall risk

    Directory of Open Access Journals (Sweden)

    Fatih Celebi

    2017-01-01

    Full Text Available Objective: The aim of this study was to investigate the effects of rapid maxillary expansion (RME on head posture, postural stability, and fall risk. Materials and Methods: A sample of 51 adolescent patients was randomly divided into two groups. In the first group, which consisted of 28 patients (15 females and 13 males, RME was performed as a part of routine orthodontic treatment. The remaining 23 individuals (12 females and 11 males served as the control group. Lateral cephalometric radiographs taken in natural head position, postural stability, and fall risk scores were obtained during the first visit. They were repeated on average 3.8 months and 3.5 months later for the study and control groups, respectively. The changes were analyzed using the Wilcoxon signed-rank test, paired samples t-test, Mann–Whitney U-test, and independent samples t-test. Results: As a result of RME, a statistically significant decrease was detected in the fall risk score (P < 0.05 in the study group, while the head position and postural stability remained unchanged. For the control group, no significant changes were observed in all measurements. Conclusions: The result of the present study suggests that RME has a capacity of improving fall risk.

  9. Effects of smartphone texting on the visual perception and dynamic walking stability.

    Science.gov (United States)

    Lim, Jongil; Chang, Seung Ho; Lee, Jihyun; Kim, Kijeong

    2017-02-01

    Mobile phone use while walking can cause dual-task interference and increases safety risks by increasing attentional and cognitive demands. While the interference effect on cognitive function has been examined extensively, how perception of the environment and walking dynamics are affected by mobile phone use while walking is not well understood. The amount of visual information loss and its consequent impact on dynamic walking stability was examined in this study. Young adults (mean, 20.3 years) volunteered and walked on a treadmill while texting and attending to visual tasks simultaneously. Performance of visual task, field of regard loss, and margin of stability under dual-task conditions were compared with those of single-task conditions (i.e., visual task only). The results revealed that the size of visual field and visual acuity demand were varied across the visual task conditions. Approximately half of the visual cues provided during texting while walking were not perceived as compared to the visual task only condition. The field of regard loss also increased with increased dual-task cost of mobile phone use. Dynamic walking stability, however, showed no significant differences between the conditions. Taken together, the results demonstrate that the loss of situational awareness is unavoidable and occurs simultaneously with decrements in concurrent task performance. The study indicates the importance of considering the nature of attentional resources for the studies in dual-task paradigm and may provide practical information to improve the safe use of mobile phones while walking.

  10. Stability of alkali-metal hydrides: effects of n-type doping

    Science.gov (United States)

    Olea Amezcua, Monica Araceli; de La Peña Seaman, Omar; Rivas Silva, Juan Francisco; Heid, Rolf; Bohnen, Klaus-Peter

    Metal hydrides could be considered ideal solid-state hydrogen storage systems, they have light weight and high hydrogen volumetric densities, but the hydrogen desorption process requires excessively high temperatures due to their high stability. Efforts have been performed to improve their dehydrogenation properties, based on the introduction of defects, impurities and doping. We present a systematic study of the n-type (electronic) doping effects on the stability of two alkali-metal hydrides: Na1-xMgxH and Li1-xBexH. These systems have been studied within the framework of density functional perturbation theory, using a mixed-basis pseudopotential method and the self-consistent version of the virtual crystal approximation to model the doping. The full-phonon dispersions are analyzed for several doping content, paying special attention to the crystal stability. It is found a doping content threshold for each system, where they are close to dynamical instabilities, which are related to charge redistribution in interstitial zones. Applying the quasiharmonic approximation, the vibrational free energy, the linear thermal expansion and heat capacities are obtained for both hydrides systems and are analyzed as a function of the doping content. This work is partially supported by the VIEP-BUAP 2016 and CONACYT-México (No.221807) projects.

  11. Effects of Sulfate, Chloride, and Bicarbonate on Iron Stability in a PVC-U Drinking Pipe

    Directory of Open Access Journals (Sweden)

    Jiaying Wang

    2017-06-01

    Full Text Available In order to describe iron stability in plastic pipes and to ensure the drinking water security, the influence factors and rules for iron adsorption and release were studied, dependent on the Unplasticized poly (vinyl chloride (PVC-U drinking pipes employed in this research. In this paper, sulfate, chloride, and bicarbonate, as well as synthesized models, were chosen to investigate the iron stability on the inner wall of PVC-U drinking pipes. The existence of the three kinds of anions could significantly affect the process of iron adsorption, and a positive association was found between the level of anion concentration and the adsorption rate. However, the scaling formed on the inner surface of the pipes would be released into the water under certain conditions. The Larson Index (LI, used for a synthetic consideration of anion effects on iron stability, was selected to investigate the iron release under multi-factor conditions. Moreover, a well fitted linear model was established to gain a better understanding of iron release under multi-factor conditions. The simulation results demonstrated that the linear model was better fitted than the LI model for the prediction of iron release.

  12. Effect of grape pomace on fermentation quality and aerobic stability of sweet sorghum silage.

    Science.gov (United States)

    Li, Ping; Shen, Yixin; You, Minghong; Zhang, Yu; Yan, Jiajun; Li, Daxue; Bai, Shiqie

    2017-10-01

    The objective of this study was to evaluate the effect of grape pomace (GP) with different adding levels (0%, 5%, 10% and 15%, fresh matter basis), alone (GP-LAB) or in combine with an inoculant LAB (GP+LAB), on the fermentation quality and aerobic stability of sweet sorghum silage. After 90 days of ensiling in vacuumized mini-silos, silages were subject to a 7-day aerobic stability test, in which chemical, microbial and polyphenol composition were measured. In the GP-LAB group, adding GP decreased (P butyric acid in silage. In the GP+LAB group, adding GP increased (P butyric acid concentration in silage. Polyphenol level was reduced (P fermentation. During aerobic exposure, the fungi count, pH value and silage temperature increased (P fermentation products, microbial counts, chemical and polyphenol composition were considered, the use of 10% GP+LAB at ensiling could provide a valuable source for improved fermentation quality and aerobic stability of sweet sorghum silage. © 2017 Japanese Society of Animal Science.

  13. The Effects of Core Stability Exercise on the Dynamic Balance of Volleyball Players

    Directory of Open Access Journals (Sweden)

    Hassan Sadeghi

    2013-12-01

    Full Text Available Dynamic balance is a key component of injury prevention and rehabilitation in sports. Training the core muscles has been hypothesized as an intervention for improving balance. However, there is a lack of current scientific evidence to support this claim. The purpose of this study was to evaluate the effects of a core stability program on dynamic balance of volleyball players as measured with the Star Excursion Balance Test (SEBT. Thirty healthy participants were divided into 2 groups: control and exercise groups. All participants performed the SEBT before and after 8-week exercise time. During the 8-week time, the exercise group performed a core stability program, whereas the control group abstained from any new exercise. These results also illustrated there was significant differences in the scores for pre-test and post-test of all direction according SEBT in the experimental group. An independent sample t-test was conducted to compare experimental and control group (F=43.573, Sig=0.000. These results were a significant difference in the scores for control and experimental groups. Maximum excursion distances improved for the exercise group, compared with the control group. This result justifies the hypothesis that core strengthening can improve dynamic postural control during landing of volleyball players significantly. Keywords: Core stabilization; volleyball player; dynamic balance; SEBT

  14. Aerodynamic characteristics of a feathered dinosaur measured using physical models. Effects of form on static stability and control effectiveness.

    Directory of Open Access Journals (Sweden)

    Dennis Evangelista

    Full Text Available We report the effects of posture and morphology on the static aerodynamic stability and control effectiveness of physical models based on the feathered dinosaur, [Formula: see text]Microraptor gui, from the Cretaceous of China. Postures had similar lift and drag coefficients and were broadly similar when simplified metrics of gliding were considered, but they exhibited different stability characteristics depending on the position of the legs and the presence of feathers on the legs and the tail. Both stability and the function of appendages in generating maneuvering forces and torques changed as the glide angle or angle of attack were changed. These are significant because they represent an aerial environment that may have shifted during the evolution of directed aerial descent and other aerial behaviors. Certain movements were particularly effective (symmetric movements of the wings and tail in pitch, asymmetric wing movements, some tail movements. Other appendages altered their function from creating yaws at high angle of attack to rolls at low angle of attack, or reversed their function entirely. While [Formula: see text]M. gui lived after [Formula: see text]Archaeopteryx and likely represents a side experiment with feathered morphology, the general patterns of stability and control effectiveness suggested from the manipulations of forelimb, hindlimb and tail morphology here may help understand the evolution of flight control aerodynamics in vertebrates. Though these results rest on a single specimen, as further fossils with different morphologies are tested, the findings here could be applied in a phylogenetic context to reveal biomechanical constraints on extinct flyers arising from the need to maneuver.

  15. Stabilizing effect of biochar on soil extracellular enzymes after a denaturing stress.

    Science.gov (United States)

    Elzobair, Khalid A; Stromberger, Mary E; Ippolito, James A

    2016-01-01

    Stabilizing extracellular enzymes may maintain enzymatic activity while protecting enzymes from proteolysis and denaturation. A study determined whether a fast pyrolysis hardwood biochar (CQuest™) would reduce evaporative losses, subsequently stabilizing soil extracellular enzymes and prohibiting potential enzymatic activity loss following a denaturing stress (microwaving). Soil was incubated in the presence of biochar (0%, 1%, 2%, 5%, or 10% by wt.) for 36 days and then exposed to microwave energies (0, 400, 800, 1600, or 3200 J g(-1) soil). Soil enzymes (β-glucosidase, β-d-cellobiosidase, N-acetyl-β-glucosaminidase, phosphatase, leucine aminopeptidase, β-xylosidase) were analyzed by fluorescence-based assays. Biochar amendment reduced leucine aminopeptidase and β-xylosidase potential activity after the incubation period and prior to stress exposure. The 10% biochar rate reduced soil water loss at the lowest stress level (400 J microwave energy g(-1) soil). Enzyme stabilization was demonstrated for β-xylosidase; intermediate biochar application rates prevented a complete loss of this enzyme's potential activity after soil was exposed to 400 (1% biochar treatment) or 1600 (5% biochar treatment) J microwave energy g(-1) soil. Remaining enzyme potential activities were not affected by biochar, and activities decreased with increasing stress levels. We concluded that biochar has the potential to reduce evaporative soil water losses and stabilize certain extracellular enzymes where activity is maintained after a denaturing stress; this effect was biochar rate and enzyme dependent. While biochar may reduce the potential activity of certain soil extracellular enzymes, this phenomenon was not universal as the majority of enzymes assayed in this study were unaffected by exposure to biochar. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Stability effects of singularities in force-controlled robotic assist devices

    Science.gov (United States)

    Luecke, Greg R.

    2002-02-01

    Force feedback is being used as an interface between humans and material handling equipment to provide an intuitive method to control large and bulky payloads. Powered actuation in the lift assist device compensates for the inertial characteristics of the manipulator and the payload to provide effortless control and handling of manufacturing parts, components, and assemblies. The use of these Intelligent Assist Devices (IAD) is being explored to prevent worker injury, enhance material handling performance, and increase productivity in the workplace. The IAD also provides the capability to shape and control motion in the workspace during routine operations. Virtual barriers can be developed to protect fixed objects in the workspace, and regions can be programmed that attract the work piece to a certain position and orientation. However, the robot is still under complete control of the human operator, with the trajectory being determined and commanded using the judgment of the operator to complete a given task. In many cases, the IAD is built in a configuration that may have singular points inside the workspace. These singularities can cause problems when the unstructured trajectory commands from the human cause interaction between the IAD and the virtual walls and fixtures at positions close to these singularities. The research presented here explores the stability effects of the interactions between the powered manipulator and the virtual surfaces when controlled by the operator. Because of the flexible nature of the human decisions determining the real time work piece paths, manipulator singularities that occur in conjunction with the virtual surfaces raise stability issues in the performance around these singularities. We examine these stability issues in the context of a particular IAD configuration, and present analytic results for the performance and stability of these systems in response to the real-time trajectory modification of the human operator.

  17. Effect of chamber stabilization software on efficiency and chatter in a porcine lens model.

    Science.gov (United States)

    Wright, Alex J; Thomson, Rhett S; Bernhisel, Ashlie A; Zaugg, Brian; Barlow, William R; Pettey, Jeff H; Olson, Randall J

    2017-11-01

    To evaluate the effects of the use of programmable chamber stabilization software (Chamber Stabilization Environment) settings on efficiency and chatter in a porcine lens model. John A. Moran Eye Center Laboratory, University of Utah, Salt Lake City, Utah, USA. Experimental study. Porcine eyes were dissected and the lenses extracted. The lenses were then hardened and processed for the experiment. Phacoemulsification of the lens fragments was performed with the Whitestar Signature Pro with the Whitestar handpiece and a 0.9 mm straight Dewey tip with a 30-degree bevel. All arms of the study were run in peristaltic mode with 50 mL/minute aspiration, 100 cm bottle height, and on 100% power. The chamber stabilization software setting was used for each of the 4 study arms with a maximum vacuum of 500 mm Hg. Arm 1 included 20 runs with the up time set to 2000 milliseconds. Arm 2 was performed with similar settings but with an up time of 0 millisecond. Arms 3 and 4 were run with up times of 1000 milliseconds and 500 milliseconds, respectively. The mean efficiency time of each run was as follows: 0 millisecond = 1.4 seconds, 500 milliseconds = 0.95 seconds, 1000 milliseconds = 0.88 seconds, 2000 milliseconds = 0.93 seconds. When compared with 0 millisecond, each of the other arms were significantly faster. Chatter events were comparable between the study arms. The chamber stabilization software does not decrease efficiency when compared with full vacuum on if at least 500 milliseconds of up time is maintained. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. The effects of a protein osmolyte on the stability of the integral membrane protein glycerol facilitator.

    Science.gov (United States)

    Baturin, Simon; Galka, Jamie J; Piyadasa, Hadeesha; Gajjeraman, S; O'Neil, Joe D

    2014-12-01

    Osmolytes are naturally occurring molecules used by a wide variety of organisms to stabilize proteins under extreme conditions of temperature, salinity, hydrostatic pressure, denaturant concentration, and desiccation. The effects of the osmolyte trimethylamine N-oxide (TMAO) as well as the influence of detergent head group and acyl chain length on the stability of the Escherichia coli integral membrane protein glycerol facilitator (GF) tetramer to thermal and chemical denaturation by sodium dodecyl sulphate (SDS) are reported. TMAO promotes the association of the normally tetrameric α-helical protein into higher order oligomers in dodecyl-maltoside (DDM), but not in tetradecyl-maltoside (TDM), lyso-lauroylphosphatidyl choline (LLPC), or lyso-myristoylphosphatidyl choline (LMPC), as determined by dynamic light scattering (DLS); an octameric complex is particularly stable as indicated by SDS polyacrylamide gel electrophoresis. TMAO increases the heat stability of the GF tetramer an average of 10 °C in the 4 detergents and also protects the protein from denaturation by SDS. However, it did not promote re-association to the tetramer when added to SDS-dissociated protein. TMAO also promotes the formation of rod-like detergent micelles, and DLS was found to be useful for monitoring the structure of the protein and the redistribution of detergent during thermal dissociation of the protein. The protein is more thermally stable in detergents with the phosphatidylcholine head group (LLPC and LMPC) than in the maltoside detergents. The implications of the results for osmolyte mechanism, membrane protein stability, and protein-protein interactions are discussed.

  19. Synergistic effects of surfactants and sugars on lipoplex stability during freeze-drying and rehydration.

    Science.gov (United States)

    Yu, Jinxiang; Anchordoquy, Thomas J

    2009-09-01

    The stability of nonviral vectors during freeze-drying has been well-studied, and it has been established that sugars can protect lipoplexes during freeze-drying. However low levels of damage are often observed after freeze-drying, and this damage is more evident in dilute lipoplex preparations. By investigating the stability of lipoplexes after each step in the freeze-drying cycle (i.e., freezing, primary drying, and secondary drying), we strive to understand the mechanisms responsible for damage and identify improved stabilization strategies. N-(1-(2,3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride (DOTAP)-cholesterol/plasmid DNA lipoplexes were prepared at an equimolar DOTAP-cholesterol ratio, and a 3:1 DOTAP(+)-DNA(-) charge ratio. Our experiments indicate that despite sufficient levels of "stabilizing" sugars, significant damage is still evident when dilute lipoplex preparations are subjected to freeze-drying. Analysis of the different stages of freeze-drying suggests that significant damage occurs during freezing, and that sugars have a limited capacity to protect against this freezing-induced damage. Similar effects have been observed in studies with proteins, and surfactants have been employed in protein formulations to protect against surface-induced damage, for example, at the ice crystal, solid, air, or sugar glass surfaces. However, the use of surfactants in a lipid-based formulation is inherently risky due to the potential for altering/solubilizing the lipid delivery vehicle. Our data indicate that judicious use of surfactants can reduce surface-induced damage and result in better preservation of lipoplex size and transfection activity after freeze-drying.

  20. Maternal effects on offspring consumption can stabilize fluctuating predator-prey systems.

    Science.gov (United States)

    Garbutt, Jennie S; Little, Tom J; Hoyle, Andy

    2015-12-07

    Maternal effects, where the conditions experienced by mothers affect the phenotype of their offspring, are widespread in nature and have the potential to influence population dynamics. However, they are very rarely included in models of population dynamics. Here, we investigate a recently discovered maternal effect, where maternal food availability affects the feeding rate of offspring so that well-fed mothers produce fast-feeding offspring. To understand how this maternal effect influences population dynamics, we explore novel predator-prey models where the consumption rate of predators is modified by changes in maternal prey availability. We address the 'paradox of enrichment', a theoretical prediction that nutrient enrichment destabilizes populations, leading to cycling behaviour and an increased risk of extinction, which has proved difficult to confirm in the wild. Our models show that enriched populations can be stabilized by maternal effects on feeding rate, thus presenting an intriguing potential explanation for the general absence of 'paradox of enrichment' behaviour in natural populations. This stabilizing influence should also reduce a population's risk of extinction and vulnerability to harvesting. © 2015 The Author(s).

  1. Dynamic stability of functionally graded nanobeam based on nonlocal Timoshenko theory considering surface effects

    Science.gov (United States)

    Saffari, Shahab; Hashemian, Mohammad; Toghraie, Davood

    2017-09-01

    Based on nonlocal Timoshenko beam theory, dynamic stability of functionally graded (FG) nanobeam under axial and thermal loading was investigated. Surface stress effects were implemented according to Gurtin-Murdoch continuum theory. Using power law distribution for FGM and von Karman geometric nonlinearity, governing equations were derived based on Hamilton's principle. The developed nonlocal models have the capability of interpreting small scale effects. Pasternak elastic medium was employed to represent the interaction of the FG nanobeam and the surrounding elastic medium. A parametric study was conducted to focus influences of the static load factor, temperature change, gradient index, nonlocal parameter, slenderness ratio, surface effect and springs constants of the elastic medium on the dynamic instability region (DIR) of the FG beam with simply-supported boundary conditions. It was found that differences between DIRs predicted by local and nonlocal beam theories are significant for beams with lower aspect ratio. Moreover, it was observed that in contrast to high temperature environments, at low temperatures, increasing the temperature change moves the origin of the DIR to higher excitation frequency zone and leads to further stability. Considering surface stress effects shifts the DIR of FG beam to higher frequency zone, also increasing the gradient index enhances the frequency of DIR.

  2. Effect of body aerodynamics on the dynamic flight stability of the hawkmoth Manduca sexta.

    Science.gov (United States)

    Nguyen, Anh Tuan; Han, Jong-Seob; Han, Jae-Hung

    2016-12-14

    This study explores the effects of the body aerodynamics on the dynamic flight stability of an insect at various different forward flight speeds. The insect model, whose morphological parameters are based on measurement data from the hawkmoth Manduca sexta, is treated as an open-loop six-degree-of-freedom dynamic system. The aerodynamic forces and moments acting on the insect are computed by an aerodynamic model that combines the unsteady panel method and the extended unsteady vortex-lattice method. The aerodynamic model is then coupled to a multi-body dynamic code to solve the system of motion equations. First, the trimmed flight conditions of insect models with and without consideration of the body aerodynamics are obtained using a trim search algorithm. Subsequently, the effects of the body aerodynamics on the dynamic flight stability are analysed through modal structures, i.e., eigenvalues and eigenvectors in this case, which are based on linearized equations of motion. The solutions from the nonlinear and linearized equations of motion due to gust disturbances are obtained, and the effects of the body aerodynamics are also investigated through these solutions. The results showed the important effect of the body aerodynamics at high-speed forward flight (in this paper at 4.0 and 5.0 m s -1 ) and the movement trends of eigenvalues when the body aerodynamics is included.

  3. An 8-week Aquatic Exercise Program is Effective at Improving Gait Stability of the Elderly

    Science.gov (United States)

    Lim, Hee Sung; Roh, Su Yeon; Yoon, Sukhoon

    2013-01-01

    [Purpose] The purpose of this study was to investigate the effect of 8 weeks aquatic exercise on the gait stability of the elderly using dynamic factors: center of mass (COM), velocity of center of mass (COMV), and center of pressure (COP). [Subjects] Eleven elderly participants (age: 77.18 ± 4.96 yrs, height: 149.48 ± 3.61 cm, body mass: 56.94 ± 6.62 kg, and leg length: 82.36 ± 2.98 cm), participated in this study. [Methods] To identify the 8-week aquatic training effect, 3-D motion analysis with 7 infrared cameras and one force plate, was performed. [Results] For the COM-COP inclination angles, significantly decreased medial inclination angles were shown in both the posterior and anterior swing phases. For the COMV-COP inclination angles, decreased medial inclination angles were shown in both the posterior and anterior swing phases, but significant difference was found only in the posterior phase. [Conclusion] The results suggest that 8 weeks aquatic exercise is effective at improving the gait stability of the elderly. Further studies should extend the training period to gain statistically significant results for the effect of aquatic exercise in the anterior-posterior direction. PMID:24396212

  4. An experimental study on the effects of temperature and magnetic field strength on the magnetorheological fluid stability and MR effect.

    Science.gov (United States)

    Rabbani, Yahya; Ashtiani, Mahshid; Hashemabadi, Seyed Hassan

    2015-06-14

    In this study, the stability and rheological properties of a suspension of carbonyl iron microparticles (CIMs) in silicone oil were investigated within a temperature range of 10 to 85 °C. The effect of adding two hydrophobic (stearic and palmitic) acids on the stability and magnetorheological effect of a suspension of CIMs in silicone oil was studied. According to the results, for preparing a stable and efficient magnetorheological (MR) fluid, additives should be utilized. Therefore, 3 wt% of stearic acid was added to the MR fluid which led to an enhancement of the fluid stability over 92% at 25 °C. By investigating shear stress variation due to the changes in the shear rate for acid-based MR fluids, the maximum yield stress was obtained by fitting the Bingham plastic rheological model at high shear rates. Based on the existing correlations of yield stress and either temperature or magnetic field strength, a new model was fitted to the experimental data to monitor the simultaneous effect of magnetic field strength and temperature on the maximum yield stress. The results demonstrated that as the magnetic field intensified or the temperature decreased, the maximum yield stress increased dramatically. In addition, when the MR fluid reached its magnetic saturation, the viscosity of fluid depended only on the shear rate.

  5. The Effects of Price Stabilization on Short-Term Returns of IPOs

    Directory of Open Access Journals (Sweden)

    Douglas Beserra Pinheiro

    2011-12-01

    Full Text Available During the price stabilization in IPOs the underwriter repurchases part of the issue (ASC for aftermarket short covering. Such activity raises question about its real purpose: to keep price artificially high and deceive investors, or avoid price fluctuation resulting from the initial flow of information and the action of flippers. Our analysis indicates that in the post stabilization period stabilized IPOs underperform non-stabilized ones; the higher the intensity of the stabilization the lower are post-stabilization returns; IPOs for which the overallotment is fully covered in the ASC underperform non-stabilized IPOs in the post-stabilization period; the same does not happen when the ASC is only partial. Therefore, both views of the stabilization process are partially right: in some cases, stabilization is used to avoid price volatility and in other cases to keep price artificially high.

  6. Effect of one-step polishing system on the color stability of nanocomposites.

    Science.gov (United States)

    Alawjali, S S; Lui, J L

    2013-08-01

    This study was to compare the effect of three different one-step polishing systems on the color stability of three different types of nanocomposites after immersion in coffee for one day and seven days and determine which nanocomposite material has the best color stability following polishing with each of the one-step polishing system. The nanocomposites tested were Tetric EvoCeram, Grandio and Herculite Précis. A total of 120 discs (40/nanocomposite, 8mm×2mm) were fabricated. Ten specimens for each nanocomposite cured under Mylar strips served as the control. The other specimens were polished with OptraPol, OneGloss and Occlubrush immersed in coffee (Nescafé) up to seven days. Color measurements were made with a spectrophotometer at baseline and after one and seven days. Two way repeated measure ANOVA, two way ANOVA and Bonferroni tests were used for statistical analyses (P<0.05). The immersion time was a significant factor in the discoloration of the nanocomposites. The effect of three one-step polishing systems on the color stability was also significant. The color change values of the materials cured against Mylar strips were the greatest. The lowest mean color change values were from the Occlubrush polished groups. The effect of the three different types of nanocomposite on the color change was significant. The highest color change values were with Tetric EvoCeram groups. The lowest color change values were with Herculite Précis groups. The color change of nanocomposite resins is affected by the type of composite, polishing procedure and the period of immersion in the staining agent. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. First Principles Calculations of Transition Metal Binary Alloys: Phase Stability and Surface Effects

    Science.gov (United States)

    Aspera, Susan Meñez; Arevalo, Ryan Lacdao; Shimizu, Koji; Kishida, Ryo; Kojima, Kazuki; Linh, Nguyen Hoang; Nakanishi, Hiroshi; Kasai, Hideaki

    2017-06-01

    The phase stability and surface effects on binary transition metal nano-alloy systems were investigated using density functional theory-based first principles calculations. In this study, we evaluated the cohesive and alloying energies of six binary metal alloy bulk systems that sample each type of alloys according to miscibility, i.e., Au-Ag and Pd-Ag for the solid solution-type alloys (SS), Pd-Ir and Pd-Rh for the high-temperature solid solution-type alloys (HTSS), and Au-Ir and Ag-Rh for the phase-separation (PS)-type alloys. Our results and analysis show consistency with experimental observations on the type of materials in the bulk phase. Varying the lattice parameter was also shown to have an effect on the stability of the bulk mixed alloy system. It was observed, particularly for the PS- and HTSS-type materials, that mixing gains energy from the increasing lattice constant. We furthermore evaluated the surface effects, which is an important factor to consider for nanoparticle-sized alloys, through analysis of the (001) and (111) surface facets. We found that the stability of the surface depends on the optimization of atomic positions and segregation of atoms near/at the surface, particularly for the HTSS and the PS types of metal alloys. Furthermore, the increase in energy for mixing atoms at the interface of the atomic boundaries of PS- and HTSS-type materials is low enough to overcome by the gain in energy through entropy. These, therefore, are the main proponents for the possibility of mixing alloys near the surface.

  8. Effect of preheat repetition on color stability of methacrylate- and silorane-based composite resins

    OpenAIRE

    Abed Kahnamouei, Mehdi; Gholizadeh, Sarah; Rikhtegaran, Sahand; Daneshpooy, Mehdi; Kimyai, Soodabeh; Alizadeh Oskoee, Parnian; Rezaei, Yashar

    2017-01-01

    Background. The aim of this study was to investigate the effect of preheating methacrylate- and silorane-based composite resins on their color stability up to 40 times at 55‒60°C. Methods. Seventy-six methacrylate and silorane-based composite resin samples, with a diameter of 10 mm and a height of 2 mm, were divided into 4 groups (n=19). After the samples were prepared, their color parameters were determined using a reflective spectrophotometer. The composite resin samples were separately sto...

  9. Effect of the thermal stabilization temperature on the change in the texture of polyacrylonitrile fiber

    Science.gov (United States)

    Fazlitdinova, A. G.; Tyumentsev, V. A.

    2015-11-01

    The effect of temperature of isothermal treatment on the change in sizes L 010 of coherent scattering regions and texture of a polyacrylonitrile fiber during its transition to the structure of a thermally stabilized fiber is analyzed using X-ray structure analysis. An increase in the thermostabilization temperature at a constant stretching load stimulates simultaneously a more active increase in size L 010 and texturing of polyacrylonitrile fibers at the initial stage. Active evolution of the phase transformation at temperatures 275-290°C during further thermostabilization is accompanied by a substantial decrease in the texture of the polymer that has not experienced the phase transformation by this instant.

  10. Effect of nitrogen alloying of stainless steels on their corrosion stability

    International Nuclear Information System (INIS)

    Chigal, V.; Knyazheva, V.M.; Pitter, Ya.; Babich, S.G.; Bogolyubskij, S.D.

    1986-01-01

    Results of corrosion tests and structural investigations of 03Cr18Ni10 and 03Cr18Ni10Mo3 steels without nitrogen and with nitrogen content of 0.15-0.3% are presented. Corrosion-electrochemical behaviour of Cr20Ni20 steel with ultralow carbon content (0.004-0.006%) and nitrogen content with 0-0.5% as well as Cr 2 N nitride behaviour are investigated. A conclusion is made on nitrogen and excessive nitride phase effect on corrosion stability of steel in corrosive media with different reduction-oxidation properties

  11. Effect of Inverter Power Source Characteristics on Welding Stability and Heat Affected Zone Dimensions

    Science.gov (United States)

    Il’yaschenko, D. P.; Chinakhov, D. A.; Mamadaliev, R. A.

    2018-01-01

    The paper presents results the research in the effect of power sources dynamic characteristics on stability of melting and electrode metal transfer to the weld pool shielded metal arc welding. It is proved that when applying inverter-type welding power sources, heat and mass transfer characteristics change, arc gap short-circuit time and drop generation time are reduced. This leads to reduction of weld pool heat content and contraction of the heat-affected zone by 36% in comparison the same parameters obtained using a diode rectifier.

  12. THE EFFECT OF MOUTHRINSES ON COLOR STABILITY OF SONICFILL AND A NANOHYBRID COMPOSITE

    OpenAIRE

    Öztürk Bozkurt, Funda; Toz Akalın, Tuğba; Genç, Gencay; Korkmaz Ceyhan, Yonca

    2016-01-01

    Purpose: The aim of this study was to evaluate the effects of 4 mouth rinses on the color stability of two different resin composites. Materials and Methods: A2 shade sonic-activated bulk fill material SonicFill (Kerr) and conventional nanohybrid composite Filtek Z550 (3M ESPE) were used. Forty disc-shaped specimens (10 mm x 2 mm) were fabricated for both composites and finished using 400-grit SiC paper and polished. After polishing and immersing in distilled water ...

  13. Effect of steady deflections on the aeroelastic stability of a turbine blade

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2011-01-01

    This paper deals with effects of geometric non-linearities on the aeroelastic stability of a steady-state defl ected blade. Today, wind turbine blades are long and slender structures that can have a considerable steady-state defl ection which affects the dynamic behaviour of the blade. The fl...... apwise blade defl ection causes the edgewise blade motion to couple to torsional blade motion and thereby to the aerodynamics through the angle of attack. The analysis shows that in the worst case for this particular blade, the edgewise damping can be decreased by half. Copyright © 2010 John Wiley & Sons......, Ltd....

  14. Effect of vertical quasiperiodic vibrations on the stability of the free surface of an inviscid liquid layer

    Directory of Open Access Journals (Sweden)

    Belhaq M.

    2012-07-01

    Full Text Available The aim of the present paper is to examine the effect of the vertical quasiperiodic oscillations on the stability of the free surface of an ideal horizontal liquid layer. The quasiperiodic motion considered here is characterized by two incommensurate frequencies ω1 and ω2. The governing system of equations is reduced to a quasiperiodic Mathieu equation. In this situation, using the harmonic balance method developed by Rand et al. [10, 11] and Hill’s determinants, we determine the marginal stability curves. We show that the quasiperiodic excitation produces a stabilizing or a estabilizing effect and is strongly depending on the ratio of the frequencies.

  15. Effects of amphiphilic diblock copolymer on drug nanoparticle formation and stability

    Science.gov (United States)

    Zhu, Zhengxi

    2013-01-01

    This study systematically compares the effects of amphiphilic diblock copolymer (di-BCP) on stabilizing hydrophobic drug nanoparticles formed by flash nanoprecipitation (FNP), and provides a guideline on choosing suitable di-BCPs. Four widely used di-BCPs, i.e., polystyrene-block-poly(ethylene glycol) (PS-b-PEG), polycaprolactone-block-poly(ethylene glycol) (PCL-b-PEG), polylactide-block-poly(ethylene glycol) (PLA-b-PEG), and poly(lactic-co-glycolic acid) (PLGA-b-PEG), and β-carotene as a model drug were used. The study showed that PLGA-b-PEG was the most suitable one, whose hydrophobic block was biodegradable and noncrystallizable as well as had relatively high glass transition temperature (Tg) and a right solubility parameter (δ). The molecular weight of PLGA block over the range from 5k to 15k showed an insignificant effect on controlling the particle size. Amorphous drug particles with a high drug loading of over 83 wt% can be achieved. Much remarkable evidence supported the nanoparticles with kinetically frozen and nonequilibrium packing structures of polymer chains rather than either the micelles or micellar nanoparticles with two well segregated polymer blocks. The thermodynamic effects of the drug and BCP on the particle stability, size and structures were discussed by using solubility parameters. PMID:24070569

  16. Nucleating Effect of Carbon Nanoparticles and Their Influence on the Thermal and Chemical Stability of Polypropylene

    Directory of Open Access Journals (Sweden)

    F. Avalos-Belmontes

    2012-01-01

    Full Text Available The effect of carbon nanofibers (CNFs and carbon nanotubes (CNTs on the thermal and chemical stability of polypropylene (PP when subjected to oxidation in a strong acid medium was studied. The effect of CNFs and CNTs on the crystalline morphology and the melting and crystallization temperatures was also studied. The thermal stability increased markedly; the decomposition temperature, for example, increased from 293∘C for pure PP to 312 and 320∘C for PP with CNFs and CNTs, respectively. The crystallization temperature increased perceptibly with the addition of CNTs or CNFs, from 107∘C for pure PP to 112 and 114∘C for PP with CNFs and CNTs, respectively. The oxidative degradation with nitric acid produced a reduction in molecular weight; however, this negative effect was less pronounced in the PP compositions with carbon nanoparticles. After 8 hours in nitric acid, this reduction was from 141,000 to 68,000 (for pure PP, to 75,000 (for PP-CNFs, and 79,500 (for PP-CNTs. X-ray diffraction showed that the alpha type crystallinity remains, irrespective of the nucleating agent. Finally, the intensity ratio between the (040 (at 16.7∘ and the (110 (at 13.9∘ reflections increased, which was taken as an indication of an increasing nucleating efficiency.

  17. Efficiency, effectiveness and treatment stability of clear aligners: A systematic review and meta-analysis.

    Science.gov (United States)

    Zheng, M; Liu, R; Ni, Z; Yu, Z

    2017-08-01

    The objective of this study was to perform a systematic review of the orthodontic literature with regard to efficiency, effectiveness and stability of treatment outcome with clear aligners compared with treatment with conventional brackets. An electronic search without time or language restrictions was undertaken in October 2014 in the following electronic databases: Google Scholar, the Cochrane Oral Health Group's Trials Register, Scopus, CENTRAL, MEDLINE via OVID, EMBASE via OVID and Web of Science. We also searched the reference lists of relevant articles. Quality assessment of the included articles was performed. Two authors were responsible for study selection, validity assessment and data extraction. Four controlled clinical trials including a total of 252 participants satisfied the inclusion criteria. We grouped the trials into four main comparisons. One randomized controlled trial was classified as level 1B evidence, and three cohort studies were classified as level 2B evidence. Clear aligners appear to have a significant advantage with regard to chair time and treatment duration in mild-to-moderate cases based on several cross-sectional studies. No other differences in stability and occlusal characteristics after treatment were found between the two systems. Despite claims about the effectiveness of clear aligners, evidence is generally lacking. Shortened treatment duration and chair time in mild-to-moderate cases appear to be the only significant effectiveness of clear aligners over conventional systems that are supported by the current evidence. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Stabilizing and destabilizing effects on plasma membrane Ca(2+)-ATPase activity.

    Science.gov (United States)

    Kosk-Kosicka, D; Wawrzynow, A; Roszczynska, G

    1994-10-12

    We have examined the temperature-dependent effects of several organic compounds on the activity of the purified Ca(2+)-ATPase of erythrocytes. The monomeric enzyme was activated either by interaction with calmodulin or by oligomerization in the absence of calmodulin. Of the four homologous solute series studied including polyols, alkanols, aprotic solvents, and N-methyl derivatives of formamide and acetamide only polyols stabilized the enzyme over a broad range of concentration and temperature. Similarity of Ca(2+)-ATPase activity patterns at 25 and 37 degrees C and in the presence of glycerol is in agreement with indirect, stabilizing interactions. Glycerol also protected the Ca(2+)-ATPase from thermal denaturation at 45 degrees C. Within each homologous series, inhibitory effects increased with increasing solute concentration and with increasing structural similarity to detergents, indicating that direct destabilizing interactions are responsible for the observed inhibition. These were comparable to the destabilizing effect of urea. Oligomers were more resistant to all inhibitory solutes as compared to calmodulin-activated monomers suggesting that the nonpolar patches of the oligomerized enzyme are less accessible to solutes.

  19. Analysis of nonlinear vibrations and stability of rotating asymmetrical nano-shafts incorporating surface energy effects

    Science.gov (United States)

    Ghodousi, Maryam; Shahgholi, Majid; Payganeh, Gholamhassan

    2018-03-01

    The objective of the present work is to investigate the nonlinear vibrations of the rotating asymmetrical nano-shafts by considering surface effect. In order to compute the surface stress tensor, the surface elasticity theory is used. The governing nonlinear equations of motion are obtained with the aid of variational approach. Bubnov-Galerkin is a very effective method for exploiting the reduced-order model of the equations of motion. The averaging method is employed to analyze the reduced-order model of the system. For this purpose, the well-known Van der Pol transformation in the complex form and angle-action transformation are utilized. The effect of surface stress on the forward and backward speeds, steady state responses of the system, fixed points, close orbits and stability of the solutions is examined. The preliminary results of the research show that the absolute values of forward and backward whirling speeds in the presence of surface effect with positive residual surface stress are higher than those of regarding the system without surface effect and in the presence of surface effect with negative residual surface stress. In addition, it is seen that the undamped rotating asymmetrical nano-shaft, for specified value of detuning parameter, in the absence or presence of surface effect has various number of stable and unstable periodic solutions. Besides, there is different number of separatrix (homoclinic orbit type). Furthermore, bifurcations, number of solutions and their stability for damped rotating asymmetrical nano-shaft are investigated. Also, the above results have been obtained for rotating symmetrical nano-shaft.

  20. A new kind of shape-stabilized PCMs with positive temperature coefficient (PTC) effect

    International Nuclear Information System (INIS)

    Cheng, Wen-long; Wu, Wan-fan; Song, Jia-liang; Liu, Yi; Yuan, Shuai; Liu, Na

    2014-01-01

    Highlights: • A new kind of shape-stabilized PCMs with PTC effect is first prepared. • It provides a potential means for the thermal control of the electronic devices. • The switching temperature of the materials is about 25 °C. • The most appropriate component of the material is found out by experimental study. • The NTC effect of the new PCMs is eliminated effectively by heat treatment. - Abstract: A new kind of shape-stabilized phase change materials (PCMs) with positive temperature coefficient (PTC) effect was prepared in this paper. The materials were prepared by adding graphite powder (GP) to the paraffin/low density polyethylene (LDPE) composite and the PTC characteristic was found by adjusting the component ratio of the material. Then the physical structures and thermal properties of the materials were investigated and the effect of various GP mass fractions and paraffin/LDPE mass proportions on the PTC behavior of the materials was studied experimentally. The results showed that the switching temperature of the materials was about 25 °C (room temperature) which approached to the first phase change temperature of paraffin dispersed in the materials. The PTC behavior of the materials was the best when the GP mass fraction and the mass proportion of LDPE/paraffin were 40 wt% and 30:70, respectively. Furthermore, the negative temperature coefficient (NTC) effect of the materials could be eliminated effectively with heat treatment. This new kind of materials is different from the former PTC materials which the switching temperatures focus on high temperature ranges. It makes up for the defect of previous materials that the switching temperatures only range in high temperature rather than room temperature and provides a potential means for the thermal control of the electronic devices or other room temperature thermal control applications

  1. Compressibility effects on ideal and kinetic ballooning modes and elimination of finite Larmor radius stabilization

    International Nuclear Information System (INIS)

    Kotschenreuther, M.

    1985-07-01

    The dynamics of ideal and kinetic ballooning modes are considered analytically including parallel ion dynamics, but without electron dissipation. For ideal modes, parallel dynamics predominantly determine the growth rate when β is within approx.30% of the ideal threshold, resulting in a substantial reduction in growth rate. Compressibility also eliminates the stabilization effects of finite Larmor radius (FLR); FLR effects (when temperature gradients are neglected) can even increase the growth rate above the MHD value. Temperature gradients accentuate this by adding a new source of free energy independent of the MHD drive, in this region of ballooning coordinate corresponding in MHD to the continuum. Analytic dispersion relations are derived demonstrating the effects above; the formalism emphasizes the similarities between the ideal MHD and kinetic cases

  2. Generation-dependent effect of PAMAM dendrimers on human insulin fibrillation and thermal stability.

    Science.gov (United States)

    Nowacka, Olga; Milowska, Katarzyna; Belica-Pacha, Sylwia; Palecz, Bartlomiej; Šipošová, Katarina; Gazova, Zuzana; Bryszewska, Maria

    2016-01-01

    We have studied the effect of polyamidoamine (PAMAM) dendrimers of various generations on the thermal stability and fibrillation of human insulin. Thermostability of human insulin used differential scanning calorimetry (DSC), which showed two phase-transitions for insulin at 60 and 82°C. After adding dendrimers at 0.6 μmol/l, the first peaks disappeared and the second peaks were higher. We posited that, in the presence of dendrimers, the dimers in the solution were transformed into hexamers. The effect of dendrimers on insulin fibrillation was monitored by measuring ThT fluorescence, and visualization of insulin fibrils by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The effect of PAMAM dendrimers on insulin fibrillation was strongly dependent on the dendrimers generation and dendrimer:protein ratio. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. The Effect of Different Perturbations on the Stability Analysis of Light Water Reactors

    International Nuclear Information System (INIS)

    Dykin, Victor

    2010-09-01

    Neutron noise analysis techniques are studied and developed, with primary use of determining the stability of Boiling Water Reactors (BWRs). In particular, the role of a specific perturbation prevailing in Light Water Reactors, the propagating density perturbation, in the stability of BWRs and on the noise field of LWRs in general, is investigated by considering three topics. In the first topics, we investigate how the neutronic response of the reactor, usually described as a second order system driven by a white noise driving force, is affected by a non-white driving force. This latter arises from the reactivity effect of the propagating density perturbations. The investigation is performed by using spectral and correlation analysis. Propagating perturbations with different velocities are analyzed. We investigate how the accuracy of the determination of the so-called decay ratio (DR) of the system, based on the assumption of white noise driving force, deteriorates with deviations from the white noise character of the driving force. In the second topics, the space dependence of the neutron noise, induced by propagating density perturbations, represented through the perturbation of the absorption, is determined and discussed. A full analytical solution was obtained by the use of the Green's function technique. The solution was analyzed for different frequencies and different system sizes. An interesting new interference effect between the point-kinetic and space-dependent components of the induced noise was discovered and interpreted in physical terms. In the last topics, a non-linear stability analysis of a BWR is performed, using so called Reduced Order Model (ROM) techniques. A ROM is usually constructed by reducing the full set of 3D space-time dependent neutron-kinetics, thermal-hydraulics and heat transfer equations to time-dependent ones, by considering space dependence in a lumped parameter model (one or two discrete channels). The main novelty of our work

  4. The Effect of Visual Stimuli on Stability and Complexity of Postural Control

    Directory of Open Access Journals (Sweden)

    Haizhen Luo

    2018-02-01

    Full Text Available Visual input could benefit balance control or increase postural sway, and it is far from fully understanding the effect of visual stimuli on postural stability and its underlying mechanism. In this study, the effect of different visual inputs on stability and complexity of postural control was examined by analyzing the mean velocity (MV, SD, and fuzzy approximate entropy (fApEn of the center of pressure (COP signal during quiet upright standing. We designed five visual exposure conditions: eyes-closed, eyes-open (EO, and three virtual reality (VR scenes (VR1–VR3. The VR scenes were a limited field view of an optokinetic drum rotating around yaw (VR1, pitch (VR2, and roll (VR3 axes, respectively. Sixteen healthy subjects were involved in the experiment, and their COP trajectories were assessed from the force plate data. MV, SD, and fApEn of the COP in anterior–posterior (AP, medial–lateral (ML directions were calculated. Two-way analysis of variance with repeated measures was conducted to test the statistical significance. We found that all the three parameters obtained the lowest values in the EO condition, and highest in the VR3 condition. We also found that the active neuromuscular intervention, indicated by fApEn, in response to changing the visual exposure conditions were more adaptive in AP direction, and the stability, indicated by SD, in ML direction reflected the changes of visual scenes. MV was found to capture both instability and active neuromuscular control dynamics. It seemed that the three parameters provided compensatory information about the postural control in the immersive virtual environment.

  5. Effect of dynamic muscular stabilization technique on low back pain of different durations.

    Science.gov (United States)

    Kumar, Suraj; Sharma, Vijai P; Aggarwal, Anoop; Shukla, Rakesh; Dev, Ravi

    2012-01-01

    Low back pain (LBP) has multi-factorial origin and its treatment varies considerably. Multidisciplinary pain programs have shown their effectiveness in the management of LBP but it is not documented whether subjects with difference in chronicity (duration) of pain will respond differently to these regimes. Dynamic muscular stabilization technique (DMST) is an active approach of stabilizing training for lumbar area which involves the training for the co-contraction of the transverse abdominis and multifidus muscles. This study determines the efficacy of Dynamic Muscular Stabilization Technique (DMST) in LBP of different durations. Follow-up, comparative study. Physical medicine and rehabilitation department (PMR) of university. Total 72 patients were categorized in 5 groups on the basis of duration (chronicity) of their low back pain. The documentation of chronicity was done on the basis of subjective questionnaire. All subjects were treated with DMST. Pain was the primary outcome measure while physical strength (back pressure change: BPC, abdominal pressure changes: APC), physical ability (walking, stair climbing, stand ups) and quality of life (QOL) were the secondary. Variables were assessed at baseline (day 0), 3 months (day 90) and at the end of the follow up (day 180). Variables (Pain, BPC, APC, Walking, Stair climbing, Stand ups and QOL) significantly improved on 90th and 180th day while compared to the baseline. Therefore irrespective of the chronicity of pain, all chronic pain patients will respond positively to the DMST treatment. This study concludes that DMST intervention is an effective rehabilitation technique for all chronic low back pain patients irrespective of the duration (chronicity) of their pain.

  6. Method of effecting fast turbine valving for improvement of power system stability

    International Nuclear Information System (INIS)

    Park, R.H.

    1981-01-01

    As a improved way of effecting fast valving of turbines of power system steam-electric generating units for the purpose of improving the stability of power transmission over transmission circuits to which their generators make connection, when stability is threatened by line faults and certain other stability endangering events, the heretofore employed and/or advocated practice of automatically closing intercept valves at fastest available closing speed in response to a fast valving signal, and thereafter automatically fully reopening them in a matter of seconds, is modified by providing to reopen the valves only partially to and thereafter retain them at a preset partially open position. For best results the process of what can be termed sustained partial reopening is so effected as to result in its completion within a fraction of a second following the peak of the first forward swing of the generator rotor. Control valves may be either held open, or automatically fully or partly closed and thereafter fully opened in a preprogrammed manner, or automatically moved to and thereafter held in a partly closed position, by means of a preprogrammed process of repositioning in which the valves may optionally be first fully or partly closed and thereafter partly reopened. Avoidance of discharge of steam through high pressure safety valves can be had with use of suitably controlled power operated valves that discharge steam to the condenser or to atmosphere. Where there is an intermediate pressure turbine that is supplied with superheated steam, use of sustained partial control valve closure, if employed, is supplemented by provision for reduction of rate of heat release within the steam generator in order to protect the reheater from overheating. As a way to restrict increase of reheat pressure of fossil fuel installations, and to minimize increase in the msr (Moisture separator-reheater) pressure of nuclear units, provision is optionally made of normally closed by-pass v

  7. Effects of stabilization training on trunk muscularity and physical performances in youth soccer players.

    Science.gov (United States)

    Hoshikawa, Yoshihiro; Iida, Tomomi; Muramatsu, Masataka; Ii, Nozomi; Nakajima, Yoshiharu; Chumank, Kentaro; Kanehisa, Hiroaki

    2013-11-01

    The purpose of the present study was to examine the effects of stabilization training on trunk muscularity and physical performances in youth male soccer players aged 12-13 yrs (n = 28). The subjects allocated to training (TG, n = 16) performed a stabilization exercise program consisting of 5 exercises (elbow-toe, elbow-heel, side bridge, modified 1-legged squat, and bent-knee push-up) 4 times per week and a training program specific to soccer 6 times per week, whereas the others (control, n = 12) conducted the soccer training only for 6 months. Before and after the intervention, the cross-sectional areas (CSAs) of 5 muscles (rectus abdominus, oblique, psoas major, quadratus lumborum, and erector spinae) were determined using magnetic resonance imaging. Furthermore, peak torques during hip extension and flexion at 1.05 rad/second, heights of squat and countermovement jumps, and time taken to sprint 15 m were also measured. After 6 months, both groups significantly increased the CSAs of the 5 muscle groups (TG: 4.4-13.4%, control: 5.5-10.9%) and improved sprint time (TG: -1.4%, control: -1.6%), without significant effect of group, but only TG significantly increased the heights of squat (5.0%) and countermovement (6.8%) jumps. In addition, a greater increase in hip extension torque was found in TG (40.8%) than in control (17.4%). The current results indicate that, at least in early adolescent soccer players, adding stabilization exercise to soccer training cannot increase the trunk muscularity, but it will improve hip extensor strength and vertical jump performance.

  8. The Effect of Core Stabilization Training Program on the Balance of Mentally Retarded Educable Students

    Directory of Open Access Journals (Sweden)

    Hassan Daneshmandi

    2013-10-01

    Full Text Available Objective: The purpose of this study was to evaluate the effect of core stabilization training program on the balance of mentally retarded educable students. Materials & Methods: The research was use Application of Quasi-experimental design with pretest and posttest control group. Our subjects included 31 students boys mentally retarded in the two groups (control, 14 patients with a mean age of 11.07±3.02years, height 152±7.86cm, weight 44.07 ± 8.08kg and (17experimental group with a mean age 11.23 ± 1.95years, height 147±7.07cm, weighing 38.11±4.85kg of the sample selected. Demographic data includes: height, weight and medical records and also the IQ of them were collected. The training program of experimental group that for 6 weeks, 3 times a week in the first three weeks experimental group performed exercise the 2 sets with 5 repetitions and three the second week of 2 sets with 10 repetitions and for evaluate used the dynamic balance Y test. For analysis data used the paired T test and independent test. Results: Results showed significant differences in mean posterior-lateral and posterior-medial in the experimental group in post-test (P&le0.05. Conclusion: People with mental retardation compared with normal people have problems with delays in motor development that seems to cause deficit in the balance. Due to the lack of balance in the people with mental retarded and the importance of balance in daily activities and the effects of core stability training on the balance was showed this training improve balance in these individuals, on base of the results of this research the core stability exercises can be performed for mental retarded by coaches and teachers.

  9. Seminal fluid from men with agenesis of the Wolffian ducts: zinc-binding properties and effects on sperm chromatin stability.

    Science.gov (United States)

    Kvist, U; Kjellberg, S; Björndahl, L; Soufir, J C; Arver, S

    1990-08-01

    Zinc-binding properties were studied in 'prostatic fluid', i.e. in seminal plasma from patients with agenesis of the Wolffian ducts, and in split-ejaculate fractions dominated by seminal vesicular fluid. The effect of seminal fluid, with different zinc-binding properties, on the stability of zinc-dependent sperm chromatin was assessed by exposing sperm to 1% sodium dodecyl sulphate (SDS) for 60 min. Citrate was the only zinc ligand in 'prostatic fluid', as revealed by gel chromatography. Zinc in this fluid enhanced the stability of sperm chromatin. In contrast, the stability of sperm chromatin was decreased in seminal plasma dominated by vesicular fluid. These results are in accordance with the concept that prostatic fluid ensures the appropriate zinc content and stability of sperm chromatin, whereas abundance of vesicular fluid may jeopardize chromatin stability by reducing chromatin zinc content.

  10. To what extent does not wearing shoes affect the local dynamic stability of walking?: effect size and intrasession repeatability.

    Science.gov (United States)

    Terrier, Philippe; Reynard, Fabienne

    2014-04-01

    Local dynamic stability (stability) quantifies how a system responds to small perturbations. Several experimental and clinical findings have highlighted the association between gait stability and fall risk. Walking without shoes is known to slightly modify gait parameters. Barefoot walking may cause unusual sensory feedback to individuals accustomed to shod walking, and this may affect stability. The objective was therefore to compare the stability of shod and barefoot walking in healthy individuals and to analyze the intrasession repeatability. Forty participants traversed a 70 m indoor corridor wearing normal shoes in one trial and walking barefoot in a second trial. Trunk accelerations were recorded with a 3D-accelerometer attached to the lower back. The stability was computed using the finite-time maximal Lyapunov exponent method. Absolute agreement between the forward and backward paths was estimated with the intraclass correlation coefficient (ICC). Barefoot walking did not significantly modify the stability as compared with shod walking (average standardized effect size: +0.11). The intrasession repeatability was high (ICC: 0.73-0.81) and slightly higher in barefoot walking condition (ICC: 0.81-0.87). Therefore, it seems that barefoot walking can be used to evaluate stability without introducing a bias as compared with shod walking, and with a sufficient reliability.

  11. EFFECTS OF CORE STABILIZATION PROGRAM AND CONVENTIONAL EXERCISES IN THE MANAGEMENT OF PATIENTS WITH CHRONIC MECHANICAL LOW BACK PAIN

    Directory of Open Access Journals (Sweden)

    Suresh Babu Reddy .A

    2015-04-01

    Full Text Available Background: Conventional back care exercises are advocated to treat the pain and to strengthen the involved muscles. There will be possibility of the pain getting recurred due to disproportionate balance and stability in the muscles. The core stabilization is major trend in rehabilitation, it aims at improving stability during functional activities, balance, flexibility, strength training and effectively manage the pain as well. Objective: To find the efficacy of the concept of core stabilization when compared to conventional back care exercises in patients with chronic mechanical low back pain. Methods: Forty patients with chronic Mechanical Low back pain were selected through purposive sampling and were randomly assigned into control group who received conventional back exercises and SWD (n=20, experimental group who received core stabilization and SWD (n=20. Both the groups received SWD, along with conventional back exercises for one group and core stabilization for the other group three days a week for 6 weeks. The treatment outcome was assessed using visual analogue scale, Rolland Morris Disability Questionnaire and Lumbar range of motion using goniometer. Results: After a 6 weeks training period the core stabilization group scored significantly higher than the conventional group for VAS (p=0.05 RMDQ (p=0.05 whereas ROM improved higher in conventional group (p=0.05. Conclusion: After the treatment sessions Core stabilization group registered a significant improvement when compared to conventional back care exercises in improving function and in relieving pain.

  12. Effects of ionic strength and sugars on the aggregation propensity of monoclonal antibodies: influence of colloidal and conformational stabilities.

    Science.gov (United States)

    Saito, Shuntaro; Hasegawa, Jun; Kobayashi, Naoki; Tomitsuka, Toshiaki; Uchiyama, Susumu; Fukui, Kiichi

    2013-05-01

    To develop a general strategy for optimizing monoclonal antibody (MAb) formulations. Colloidal stabilities of four representative MAbs solutions were assessed based on the second virial coefficient (B 2) at 20°C and 40°C, and net charges at different NaCl concentrations, and/or in the presence of sugars. Conformational stabilities were evaluated from the unfolding temperatures. The aggregation propensities were determined at 40°C and after freeze-thawing. The electrostatic potential of antibody surfaces was simulated for the development of rational formulations. Similar B 2 values were obtained at 20°C and 40°C, implying little dependence on temperature. B 2 correlated quantitatively with aggregation propensities at 40°C. The net charge partly correlated with colloidal stability. Salts stabilized or destabilized MAbs, depending on repulsive or attractive interactions. Sugars improved the aggregation propensity under freeze-thaw stress through improved conformational stability. Uneven and even distributions of potential surfaces were attributed to attractive and strong repulsive electrostatic interactions. Assessment of colloidal stability at the lowest ionic strength is particularly effective for the development of formulations. If necessary, salts are added to enhance the colloidal stability. Sugars further improved aggregation propensities by enhancing conformational stability. These behaviors are rationally predictable according to the surface potentials of MAbs.

  13. Effect of stump flexion contracture with and without prosthetic alignment intervention towards postural stability among transtibial prosthesis users

    Science.gov (United States)

    Ghazali, M. F.; Razak, N. A. Abd; Abu Osman, N. A.; Gholizadeh, H.

    2017-06-01

    Knee flexion contracture on a stump side is a phenomenon in which the stump cannot move in normal range of motion (ROM) or cannot be fully extended. This study has been carried out by using Biodex Stability System (BSS) in order to investigate the effect of stump flexion contracture towards the postural stability among the transtibial prosthesis users with the intervention of alignment accommodation. The BSS provides the reading of anterior-posterior stability index (APSI), medial-lateral stability index (MLSI), and overall stability index (OSI). Higher reading of the index indicates lesser stability. Each of the subjects had been tested in three different sessions that were Visit 1 (before contracture improvement), Visit 2 (after contracture improvement without alignment readjustment), and Visit 3 (after contracture improvement with alignment readjustment). The APSI reading was significantly higher during Visit 2 compared to Visit 1 and Visit 3. The OSI during Visit 2 was also found significantly higher compared to Visit 3. In Visit 2, the degree of contracture was significantly improved with 44.1% less than Visit 1. The stability index in anterior-posterior aspect (APSI) was proven to be lower as the prosthetic alignment was adjusted according to the ROM of knee. This finding explained that the alignment set up based on the adaptation with the stump’s ROM can contribute positively in maintaining postural stability.

  14. Rotation and toroidal magnetic field effects on the stability of two-component jets

    Science.gov (United States)

    Millas, Dimitrios; Keppens, Rony; Meliani, Zakaria

    2017-09-01

    Several observations of astrophysical jets show evidence of a structure in the direction perpendicular to the jet axis, leading to the development of 'spine and sheath' models of jets. Most studies focus on a two-component jet consisting of a highly relativistic inner jet and a slower - but still relativistic - outer jet surrounded by an unmagnetized environment. These jets are believed to be susceptible to a relativistic Rayleigh-Taylor-type instability, depending on the effective inertia ratio of the two components. We extend previous studies by taking into account the presence of a non-zero toroidal magnetic field. Different values of magnetization are examined to detect possible differences in the evolution and stability of the jet. We find that the toroidal field, above a certain level of magnetization σ, roughly equal to 0.01, can stabilize the jet against the previously mentioned instabilities and that there is a clear trend in the behaviour of the average Lorentz factor and the effective radius of the jet when we continuously increase the magnetization. The simulations are performed using the relativistic MHD module from the open source, parallel, grid adaptive, mpi-amrvac code.

  15. Effects of grab bar on utilized friction and dynamic stability when elderly people enter the bathtub.

    Science.gov (United States)

    Sekiguchi, Yusuke; Kato, Tomohisa; Honda, Keita; Kanetaka, Hiroyasu; Izumi, Shin-Ichi

    2017-08-01

    The effect of the grab bar on dynamic stability when elderly people enter the bathtub remains unclear. The purpose of the present study is to examine the age-related effect of the grab bar on dynamic stability during lateral stepping over an obstacle when entering bathtub. Sixteen young, healthy adults and sixteen elderly adults participated. The subjects performed lateral stepping over an obstacle with and without vertical and horizontal bars. Displacement and velocity of the center of mass and utilized friction, which is the required coefficient of friction to avoid slipping, were simultaneously measured by a three-dimensional motion analysis system and two force plates. A post hoc test for two-way ANOVA revealed that velocity of the center of mass in the vertical direction (pbar were significantly slower and smaller than those without the grab bar in young and elderly people. Moreover, the utilized friction at push off of the trailing leg with the vertical bar in elderly people was lower (pbar. The use of each grab bar while performing a lateral step over an obstacle may help maintaining balance in lateral and vertical directions. However, use of the vertical bar while lateral stepping over an object in elderly people may need low utilized friction to prevent slipping. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Effectiveness of cement-based systems for stabilization and solidification of spent pot liner inorganic fraction.

    Science.gov (United States)

    Silveira, B I; Dantas, A E M; Blasques, J E M; Santos, R K P

    2003-03-17

    Approximately 7000 t of spent pot liner (SPL) wastes are generated annually from activities associated with Alumi;nio Brasileiro S.A. (ALBRAS) plant located at Barcarena, Pará state, Brazil. The inorganic fraction of SPL contains high level of toxic compounds like cyanide and fluoride; its safe disposal has been the subject of serious discussions in Brazil. This study evaluated the option of a cement-based stabilization/solidification system as an effective means for safe disposal of SPL inorganic fraction in the field. The studies were carried out with concrete hexagonal blocks manufactured with a constant mass of 10% (w/w) of waste, 20% (w/w) of cement, and varied percentages of water, coarse aggregate, sand, and additives. The concrete matrices porosity and compressive strength were controlled by using microsilica (MS) and superplaticizer (SP). The results showed an average pH values for the SPL inorganic fraction and fragmented blocks of 10.2 and 11.1, respectively. Mixing the waste with concrete ingredients the solidification/stabilization effectiveness for the leachable cyanides and fluorides were of 59.33 and 57.95%, respectively. The results showed that the water/cement (W/C) ratio reduction through superplasticizer addition improved the compressive strength and the required value of 35 MPa was reached with blocks manufactured with 10 and 15% (weight of cement) of microsilica, after 28 days of curing time. Copyright 2003 Elsevier Science B.V.

  17. The effects of gallic/ferulic/caffeic acids on colour intensification and anthocyanin stability.

    Science.gov (United States)

    Qian, Bing-Jun; Liu, Jian-Hua; Zhao, Shu-Juan; Cai, Jian-Xiong; Jing, Pu

    2017-08-01

    The mechanism by which copigments stabilize colour, by protecting anthocyanin chromophores from nucleophilic attack, seems well accepted. This study was to determine effects of gallic/ferulic/caffeic acids on colour intensification and anthocyanin stability. Molecular dynamics simulations were applied to explore molecular interactions. Phenolic acids intensified the colour by 19%∼27%. Colour fading during heating followed first-order reactions with half-lives of 3.66, 9.64, 3.50, and 3.39h, whereas anthocyanin degradation, determined by the pH differential method (or HPLC-PDA), followed second-order reactions with half-lives of 3.29 (3.40), 3.43 (3.39), 2.29 (0.39), and 2.72 (0.32)h alone or with gallic/ferulic/caffeic acids, respectively, suggesting that anthocyanin degradation was faster than the colour fading. The strongest protection of gallic acids might be attributed to the shortest distance (4.37Å) of its aromatic ring to the anthocyanin (AC) panel. Hyperchromic effects induced by phenolic acids were pronounced and they obscured the accelerated anthocyanin degradation due to self-association interruption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The effectiveness and long-term stability of overbite correction with incisor intrusion mechanics.

    Science.gov (United States)

    Al-Buraiki, Huda; Sadowsky, Cyril; Schneider, Bernard

    2005-01-01

    Correction of deep overbite with subsequent achievement of long-term stability is difficult. The purpose of this study was to investigate the effectiveness and long-term stability of overbite correction with incisor intrusion mechanics. The treated group consisted of 25 subjects (13 female, 12 male) with deep overbite of at least 4 mm (mean overbite, 5.9 mm). The orthodontic treatment was initiated in the late mixed or early permanent dentition, and all patients were treated nonextraction. All patients had lateral cephalometric radiographs taken at pretreatment (T1), posttreatment (T2), and postretention (T3). The treatment included cervical headgear and lever arches to intrude mainly the maxillary incisors and occasionally the mandibular incisors. Premolars were not included in the fixed appliances during the treatment. The untreated group consisted of 25 age- and sex-matched subjects from the Bolton Growth Study. The mechanics used were effective in overbite correction. During the posttreatment period, overbite increased by 0.7 mm. Although this change was statistically significant, the amount was small and is considered clinically insignificant, given the severity of the overbite pretreatment. Furthermore, a net overbite correction (T3-T1) of 3.3 mm and postretention overbite on 2.6 mm is an excellent clinical outcome.

  19. Atypical effects of incorporated surfactants on stability and dissolution properties of amorphous polymeric dispersions.

    Science.gov (United States)

    Al-Obaidi, Hisham; Lawrence, M Jayne; Buckton, Graham

    2016-11-01

    To understand the impact of ionic and non-ionic surfactants on the dissolution and stability properties of amorphous polymeric dispersions using griseofulvin (GF) as a model for poorly soluble drugs. Solid dispersions of the poorly water-soluble drug, griseofulvin (GF) and the polymers, poly(vinylpyrrolidone) (PVP) and poly(2-hydroxypropyl methacrylate) (PHPMA), have been prepared by spray drying and bead milling and the effect of the ionic and non-ionic surfactants, namely sodium dodecyl sulphate (SDS) and Tween-80, on the physico-chemical properties of the solid dispersions studied. The X-ray powder diffraction data and hot-stage microscopy showed a fast re-crystallisation of GF. While dynamic vapour sorption (DVS) measurements indicated an increased water uptake, slow dissolution rates were observed for the solid dispersions incorporating surfactants. The order by which surfactants free dispersions were prepared seemed critical as indicated by DVS and thermal analysis. Dispersions prepared by milling with SDS showed significantly better stability than spray-dried dispersions (drug remained amorphous for more than 6 months) as well as improved dissolution profile. We suggest that surfactants can hinder the dissolution by promoting aggregation of polymeric chains, however that effect depends mainly on how the particles were prepared. © 2016 Royal Pharmaceutical Society.

  20. Flashing in riser and its effect on flow stability in natural circulation system

    International Nuclear Information System (INIS)

    Wu Xinxin; Wu Shaorong; Jiang Shengyao; Zhou Lei; Tong Yunxian; Zhang Youjie; Han Bing

    1991-09-01

    The experimental investigation was performed in the full scale thermo-hydraulic simulation test loop (HRTL-5) for the 5 MW-Heating Reactor at Institute of Nuclear Energy Technology, Tsinghua University. Under different pressures the flashing in riser of natural circulation system and its effect on flow stability were studied by the method of visual observation in synchronism with data recording. The results show that the lower the system pressure, the more obvious the flashing in the riser, and the stronger the effect on flow stability in the natural circulation system. Under very low pressure even if subcooling at the exit of heated test section is relatively higher, the flashing riser will appears due to gradual energy accumulation by strong thermodynamic non-equilibrium process. Consequently, a long period flow oscillation is stimulated in the system, and the time of period can be up to 40 s. When the system pressure reaches to 1.5 MPa, the flashing in riser is vanished. Based on these experiments, the mechanism of flashing in riser and the flow instability stimulated by the flashing are basically explained

  1. [Effects of soil properties on the stabilization process of cadmium in Cd alone and Cd-Pb contaminated soils].

    Science.gov (United States)

    Wu, Man; Xu, Ming-Gang; Zhang, Wen-Ju; Wu, Hai-Wen

    2012-07-01

    In order to clarify the effects of soil properties on the stabilization process of the cadmium (Cd) added, 11 different soils were collected and incubated under a moisture content of 65%-70% at 25 degrees C. The changes of available Cd contents with incubation time (in 360 days) in Cd and Cd-Pb contaminated treatments were determined. The stabilization process was simulated using dynamic equations. The results showed that after 1.0 mg x kg(-1) Cd or 500 mg x kg(-1) Pb + 1.0 mg x kg(-1) Cd were added into the soil, the available Cd content decreased rapidly during the first 15 days, and then the decreasing rate slowed down, with an equilibrium content reached after 60 days' incubation. In Cd-Pb contaminated soils, the presence of Pb increased the content of available Cd. The stabilization process of Cd could be well described by the second-order equation and the first order exponential decay; meanwhile, dynamic parameters including equilibrium content and stabilization velocity were used to characterize the stabilization process of Cd. These two key dynamic parameters were significantly affected by soil properties. Correlation analysis and stepwise regression suggested that high pH and high cation exchange capacity (CEC) significantly retarded the availability of Cd. High pH had the paramount effect on the equilibrium content. The stabilization velocity of Cd was influenced by the soil texture. It took shorter time for Cd to get stabilized in sandy soil than in the clay.

  2. The Effects of Consecutive Supervised Functional Lumbar Stabilizing Exercises on the Postural Balance and Functional Disability in Low Back Pain

    Directory of Open Access Journals (Sweden)

    Noureddin Karimi

    2014-06-01

    Full Text Available Objectives: The aim of this study was to examine the effects of consecutively supervised core stability training on postural control and functional disability in female patients with non-specific chronic low back pain. Methods: Twenty nine female participants with non-specific chronic low back pain participated in the study. They were randomly divided into two groups: experimental group (10 days consecutively core stability exercises under physical therapist’s supervision and control group (without intervention. Before and after the intervention, stability situations, pain intensity and functional disability were assessed with Biodex, visual Analogue Scale, Oswestry and Quebec questionnaire scales respectively. Data were analyzed by using statistical methods, independent T test and ANCOVA. Results: The study results indicated no statistically significant differences in all variables except age between two groups before intervention. Analysis by ANCOVA showed a significant difference in disability, pain intensity, Overall Stability Index with Double Leg Eyes Closed, Anterior-Posterior Stability Index with Double Leg Eyes Closed and Medio-Lateral Stability Index with Double Leg Eyes Closed scores between two groups after intervention. However, other variable differences were not significant while these changes were greater in the intervention group. Discussion: The present study indicates that consecutively supervised core stability training is an effective approach in pain relief and improving postural control in female patients with non-specific chronic low back pain.

  3. Dynamic stability of running: The effects of speed and leg amputations on the maximal Lyapunov exponent

    Energy Technology Data Exchange (ETDEWEB)

    Look, Nicole [Department of Applied Mathematics, University of Colorado Boulder, Boulder, Colorado 80309 (United States); Arellano, Christopher J.; Grabowski, Alena M.; Kram, Rodger [Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado 80309 (United States); McDermott, William J. [The Orthopedic Specialty Hospital, Murray, Utah 84107 (United States); Bradley, Elizabeth [Department of Computer Science, University of Colorado Boulder, Boulder, Colorado 80309, USA and Santa Fe Institute, Santa Fe, New Mexico 87501 (United States)

    2013-12-15

    In this paper, we study dynamic stability during running, focusing on the effects of speed, and the use of a leg prosthesis. We compute and compare the maximal Lyapunov exponents of kinematic time-series data from subjects with and without unilateral transtibial amputations running at a wide range of speeds. We find that the dynamics of the affected leg with the running-specific prosthesis are less stable than the dynamics of the unaffected leg and also less stable than the biological legs of the non-amputee runners. Surprisingly, we find that the center-of-mass dynamics of runners with two intact biological legs are slightly less stable than those of runners with amputations. Our results suggest that while leg asymmetries may be associated with instability, runners may compensate for this effect by increased control of their center-of-mass dynamics.

  4. Nonlinear effects in Paul traps operated in the second stability region: analytical analysis and numerical verification.

    Science.gov (United States)

    Xiong, Caiqiao; Zhou, Xiaoyu; Zhang, Ning; Zhan, Lingpeng; Chen, Suming; Nie, Zongxiu

    2014-11-01

    Paul trap working in the second stability region has long been recognized as a possible approach for achieving high-resolution mass spectrometry (MS), which however is still far away from the experimental implementations because of the narrow working area and inefficient ion trapping. Full understanding of the ion motional behavior is helpful for solving the problem. In this article, the ion motion in a superimposed octopole field, which was characterized by the nonlinear Mathieu equation, was solved analytically using Poincare-Lighthill-Kuo (PLK) method. This method equivalently described the nonlinear disturbance by an effective quadrupole field with perturbed Mathieu parameters, a(u) and q(u), which would bring huge convenience in the studies of nonlinear ion dynamics and was, therefore, used for rapid evaluation of the nonlinear effects of ion motion. Fourth-order Runge-Kutta method (4th R-K) indicated the error of PLK for characterizing the frequency shift of ion motion was within 15%.

  5. Dynamic stability of running: The effects of speed and leg amputations on the maximal Lyapunov exponent

    International Nuclear Information System (INIS)

    Look, Nicole; Arellano, Christopher J.; Grabowski, Alena M.; Kram, Rodger; McDermott, William J.; Bradley, Elizabeth

    2013-01-01

    In this paper, we study dynamic stability during running, focusing on the effects of speed, and the use of a leg prosthesis. We compute and compare the maximal Lyapunov exponents of kinematic time-series data from subjects with and without unilateral transtibial amputations running at a wide range of speeds. We find that the dynamics of the affected leg with the running-specific prosthesis are less stable than the dynamics of the unaffected leg and also less stable than the biological legs of the non-amputee runners. Surprisingly, we find that the center-of-mass dynamics of runners with two intact biological legs are slightly less stable than those of runners with amputations. Our results suggest that while leg asymmetries may be associated with instability, runners may compensate for this effect by increased control of their center-of-mass dynamics

  6. Experimental and numerical investigation on the motorcycle front frame flexibility and its effect on stability

    Science.gov (United States)

    Cossalter, V.; Doria, A.; Massaro, M.; Taraborrelli, L.

    2015-08-01

    It is well known that front fork flexibility may have a significant effect on motorcycle stability. This work addresses the problem of developing lumped element models of the front fork from experimental results. The front forks of an enduro motorcycle and of a super sport motorcycle are characterized performing static, dynamic and modal tests by means of specific testing equipment. The concept of wheel twisting axis is proposed to characterize static and dynamic deformability of the front fork. Modal analysis results show the presence of two important modes of vibration of the front assembly in the low frequency range: the lateral mode and the longitudinal mode. Different lumped models are discussed and a new model that takes into account information obtained from static and dynamic tests is proposed. Simulations are carried out by means of a multibody code and show the effect of the front assembly deformability on the weave and wobble vibration modes.

  7. Direct and indirect effects of unilateral divorce law on marital stability.

    Science.gov (United States)

    Kneip, Thorsten; Bauer, Gerrit; Reinhold, Steffen

    2014-12-01

    Previous research examining the impact of unilateral divorce law (UDL) on the prevalence of divorce has provided mixed results. Studies based on cross-sectional cross-country/cross-state survey data have received criticism for disregarding unobserved heterogeneity across countries, as have studies using country-level panel data for failing to account for possible mediating mechanisms at the micro level. We seek to overcome both shortcomings by using individual-level event-history data from 11 European countries (SHARELIFE) and controlling for unobserved heterogeneity over countries and cohorts. We find that UDL in total increased the incidence of marital breakdown by about 20 %. This finding, however, neglects potential selection effects into marriage. Accordingly, the estimated effect of unilateral divorce laws becomes much larger when we control for age at marriage, which is used as indicator for match quality. Moreover, we find that UDL particularly affects marital stability in the presence of children.

  8. Uricase alkaline enzymosomes with enhanced stabilities and anti-hyperuricemia effects induced by favorable microenvironmental changes

    Science.gov (United States)

    Zhou, Yunli; Zhang, Mi; He, Dan; Hu, Xueyuan; Xiong, Huarong; Wu, Jianyong; Zhu, Biyue; Zhang, Jingqing

    2016-01-01

    Enzyme therapy is an effective strategy to treat diseases. Three strategies were pursued to provide the favorable microenvironments for uricase (UCU) to eventually improve its features: using the right type of buffer to constitute the liquid media where catalyze reactions take place; entrapping UCU inside the selectively permeable lipid vesicle membranes; and entrapping catalase together with UCU inside the membranes. The nanosized alkaline enzymosomes containing UCU/(UCU and catalase) (ESU/ESUC) in bicine buffer had better thermal, hypothermal, acid-base and proteolytic stabilities, in vitro and in vivo kinetic characteristics, and uric acid lowering effects. The favorable microenvironments were conducive to the establishment of the enzymosomes with superior properties. It was the first time that two therapeutic enzymes were simultaneously entrapped into one enzymosome having the right type of buffer to achieve added treatment efficacy. The development of ESU/ESUC in bicine buffer provides valuable tactics in hypouricemic therapy and enzymosomal application. PMID:26823332

  9. Effect of pulse pressure on borehole stability during shear swirling flow vibration cementing.

    Directory of Open Access Journals (Sweden)

    Zhihua Cui

    Full Text Available The shear swirling flow vibration cementing (SSFVC technique rotates the downhole eccentric cascade by circulating cementing fluid. It makes the casing eccentrically revolve at high speed around the borehole axis. It produces strong agitation action to the annulus fluid, makes it in the state of shear turbulent flow, and results in the formation of pulse pressure which affects the surrounding rock stress. This study was focused on 1 the calculation of the pulse pressure in an annular turbulent flow field based on the finite volume method, and 2 the analysis of the effect of pulse pressure on borehole stability. On the upside, the pulse pressure is conducive to enhancing the liquidity of the annulus fluid, reducing the fluid gel strength, and preventing the formation of fluid from channeling. But greater pulse pressure may cause lost circulation and even formation fracturing. Therefore, in order to ensure smooth cementing during SSFVC, the effect of pulse pressure should be considered when cementing design.

  10. Experimental Study of Hydrogen Addition Effects on a Swirl-Stabilized Methane-Air Flame

    Directory of Open Access Journals (Sweden)

    Mao Li

    2017-11-01

    Full Text Available The effects of H2 addition on a premixed methane-air flame was studied experimentally with a swirl-stabilized gas turbine model combustor. Experiments with 0%, 25%, and 50% H2 molar fraction in the fuel mixture were conducted under atmospheric pressure. The primary objectives are to study the impacts of H2 addition on flame lean blowout (LBO limits, flame shapes and anchored locations, flow field characteristics, precessing vortex core (PVC instability, as well as the CO emission performance. The flame LBO limits were identified by gradually reducing the equivalence ratio until the condition where the flame physically disappeared. The time-averaged CH chemiluminescence was used to reveal the characteristics of flame stabilization, e.g., flame structure and stabilized locations. In addition, the inverse Abel transform was applied to the time-averaged CH results so that the distribution of CH signal on the symmetric plane of the flame was obtained. The particle image velocimetry (PIV was used to detect the characteristics of the flow field with a frequency of 2 kHz. The snapshot method of POD (proper orthogonal decomposition and fast Fourier transform (FFT were adopted to capture the most prominent coherent structures in the turbulent flow field. CO emission was monitored with an exhaust probe that was installed close to the combustor exit. The experimental results indicated that the H2 addition extended the flame LBO limits and the operation range of low CO emission. The influence of H2 addition on the flame shape, location, and flow field was observed. With the assistance of POD and FFT, the combustion suppression impacts on PVC was found.

  11. The Effect of Core Stabilization Training (Six Weeks on Falling Rate in Elderly Female

    Directory of Open Access Journals (Sweden)

    Soolmaz Mahdavi

    2010-10-01

    Full Text Available Objectives: The purpose of this study was to examine the effect of core stabilization Abstract training program on falling in elderly population. Methods & Materials: For this clinical trial study, forty elderly female subject (age: 70.58±5.98 years, weight: 55.76±5.78 kg, height: 157.76±7.8 cm voluntarily participated. A week prior to starting training program the balance measured with the Berg Balance Test (BBT and subjects divided into two groups, based on obtained score in BBT low risk falling (group 1, high risk falling (group 2 groups. Then subjects divided to two control & Experimental groups. The Experimental groups performed a core stabilization program included three levels for 6- week and three times per week on the alternate day and 30 min in section. The post-test of BBT were done for two groups afterwards. Independent and dependent t-test used to analyze the data. Significant level Considered to be %0.05. Results: In group 1&2 no Significant differences shown for pretest of balance between control & experimental groups (P=0.486, P=0.193. The balance of experimental groups compared to control groups improved after training program (P=0.007, P=0.000. Rate of improvement in experimental groups 1 and 2 were 3.38% and 15/06% and fore control groups were 0.95% and 3.7% respectively. Conclusion: Core stabilization training program may improve balance and decrease falling in elderly.

  12. The effect of core stability exercises on functional capacity and fatigue in patients with multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Hosein Shahrokhi

    2017-06-01

    Full Text Available Background : Multiple sclerosis (MS is a chronic progressive disease on the central nervous system with signs and symptoms such as fatigue and reduced functional capacity. The purpose of this study was to assess the effect of core stability exercises on functional capacity and fatigue in patients with multiple sclerosis. Materials and Methods: The present quasi-experimental study used a pretest-posttest design. The subjects with the age of 20-40, expanded disability status scale (EDSS 1-4 and purposefully and voluntarily selected and randomly allocated to the experimental and control groups. Training program for groups were carried out in eight weeks, three sessions per week and each session one hour. Functional reach test (FR was used to measure functional capacity and Fatigue Severity Scale (FSS was used to measure fatigue. The data were analyzed by paired and independent sample t-test at a significance level of 0.05. Results: The results showed that core stability training led to a significant increase in functional capacity and a significant reduction in fatigue (P≤ 0.05. Also significant differences observed in functional capacity and fatigue scale in post-test between experimental and control groups (P≤ 0.05. Conclusion: According to research findings, the core stability exercises can be factor for considerable improvement in functional capacity and reduced fatigue in patients with multiple sclerosis.   . Furthermore, the respective specialists can use these exercise as a complementary treatment along with the drug therapy for patients with multiple sclerosis.

  13. Effect of seed quality on oxidative stability of cold-pressed sunflower oil

    Directory of Open Access Journals (Sweden)

    Dimić Etelka B.

    2015-01-01

    Full Text Available The objective of this study was to investigate the impact of the storage time, content of the husk and impurities in the seed mass on the oxidative stability of the cold pressed sunflower oil. The oxidative stability of oil was analyzed by the RSM (Response Surface Methodology, where the response value (output of the model was the content of oxidation products measured via specific absorbance at 232 nm for conjugated dienes and 270 nm for conjugated trienes. Analyses were performed on the fresh oil samples and oil samples tempered under the Schaal-Oven’s test conditions (96 h at 63±2ºC. It was concluded that the seed storage time had significant impact on the primary (A1%232nm and secondary (A1%270nm oil oxidation products, both before (b1-p<0,001; b1-p=0,021 and after (b1-p=0,048; b1-p=0,033 the heating of oil. The content of impurities and husks in the seeds used for pressing also had an influence of the conjugated dienes and trienes contents in both, fresh and heated oil samples. However, their impact was not statistically significant. Interaction of seed storage time, the content of impurities and husks also exert some effect on the values of these quality parameters in the fresh oil as well as in the oil after the heat treatment, even though their influence is not significant. The obtained results have shown that the cold pressed sunflower oil had a good oxidative stability at temperatures up to 63±2ºC.

  14. Effect of the drug-matrix on the stability of enalapril maleate in tablet formulations.

    Science.gov (United States)

    Al-Omari, M M; Abdelah, M K; Badwan, A A; Jaber, A M

    2001-07-01

    The chemical stability of enalapril maleate in tablet dosage forms consisting of different formulation excipients has been studied in this work. The influence of various parameters such as heat, moisture, light and the drug-matrix was investigated. The degradation of enalapril maleate has been followed by using an HPLC method, which was demonstrated to be specific, stability indicating, accurate and precise. The degradation kinetics of enalalpril maleate in phosphate buffer solutions of pH values in the range of 2.2-10.5 were observed to be psuedo first order throughout the whole pH range studied. Enalapril maleate alone showed high stability for temperature under dry and humid conditions, however it became unstable when mixed with the drug-matrix in its tablet formulations and exposed to the same conditions. The pathway of degradation of enalapril maleate was found to be pH dependent. The extent of degradation of two different enalapril maleate tablet formulations (product A of a basic drug-matrix and product B of an acidic drug-matrix) has been investigated. The degree of degradation of the product with acidic matrix was significantly less than that of the basic matrix under same temperature and humidity conditions. In fact, diketopiperazine and enalaprilat degradants were mainly associated with the degradation of the product with the acidic matrix and that with the basic matrix, respectively. Dry enalapril maleate powder showed some photolysis, which was more significant with daylight (3.3%) compared with that under UV light (0.2%). Although the product with the acidic matrix showed some photolysis but the effect was not pronounced and the % recovery of enalapril was almost complete and within the acceptable experimental errors. However, the product with the basic matrix showed almost no response for photolysis.

  15. Effects of endogenous hydrogen peroxide and glutathione on the stability of arsenic metabolites in rat bile

    International Nuclear Information System (INIS)

    Kobayashi, Yayoi; Hirano, Seishiro

    2008-01-01

    Trivalent arsenicals such as arsenite (iAs III ), monomethylarsonous acid (MMA III ) and dimethylarsinous acid (DMA III ) are more toxic than analogous pentavalent compounds such as arsenate (iAs V ), monomethylarsonic acid (MMA V ) and dimethylarsinic acid (DMA V ). It has been reported that arsenic-glutathione (As-GSH) complexes such as arsenic triglutathione (ATG) and methylarsenic diglutathione (MADG) are major metabolites in rat bile following intravenous administration of iAs III . Recently, we have shown that both ATG and MADG are unstable and easily hydrolyzed to iAs III and MMA III , respectively, and that MMA III is oxidized to MMA V in bile. In the present study we report the effects of H 2 O 2 and GSH on the stability of As-GSH complexes in rat bile. Male SD rats were injected intravenously with saline or iAs III at a dose of 0.2 or 2.0 mg As/kg body weight, and bile fluid was collected on ice for 30 min. To estimate the stability of As-GSH complexes in bile, ATG or MADG was added to untreated, heat-treated, catalase-treated, or dialyzed bile, and then incubated at 37 deg. C for 10 min. Concentrations of biliary H 2 O 2 and GSH in the higher dose group were 12.6- and 4.5-times higher than the control value, respectively. Exogenously added trivalent arsenicals were oxidized to pentavalent arsenicals in the bile depending on the biliary concentration of H 2 O 2 . Both catalase and dialysis prevented oxidation of trivalent arsenicals to the corresponding pentavalent compounds. Exogenously added GSH stabilized As-GSH complexes in bile. These results suggest that H 2 O 2 converts trivalent arsenicals to less toxic pentavalent arsenicals, whereas GSH prevents hydrolysis of As-GSH complexes and the generation of unconjugated toxic trivalent arsenicals

  16. Characterizing the collagen stabilizing effect of crosslinked chitosan nanoparticles against collagenase degradation.

    Science.gov (United States)

    Kishen, Anil; Shrestha, Suja; Shrestha, Annie; Cheng, Calvin; Goh, Cynthia

    2016-08-01

    Antibacterial and chelating properties of chitosan has been widely studied for various dental applications. To characterize the interaction between chitosan-nanoparticles (CSnp) and collagen, and understand their stabilizing effect against collagenase degradation for dentin matrix stabilization. Phase-1: a single Type I collagen-fibril model was used to study the interaction with CSnp along with carbodiimides crosslinking treatment. Degradation of the crosslinked fibrils was studied with bacterial collagenase enzyme and monitored using Fourier Transform Infrared (FTIR) spectroscopy, turbidity measurement (400nm), ninhydrin assay and Atomic Force Microscopy (AFM). Interaction of CSnp with collagenase and Type I collagen, were evaluated using SDS-PAGE, and proteolytic cleavage potential of a synthetic peptide. Phase-2: degradation of dentin collagen crosslinked with/without CSnp was evaluated using FTIR, ninhydrin assay and Scanning Electron Microscopy (SEM). Glutaraldehyde crosslinking was used as a positive control. Both native collagen-fibrils and dentin collagen after crosslinking showed higher resistance to collagenase degradation, as observed in turbidity measurements and FTIR spectra. AFM images showed the interaction of CSnp with single collagen-fibril and crosslinked collagen resisted collagenase degradation up to 54h. The collagen and collagenase both formed complexes with CSnp resulting in thickening of bands and reduction in collagen degradation. CSnp treated collagenase showed significantly reduced cleavage of the fluorescent peptides. Dentin collagen was coated with CSnp following crosslinking with significant increase in resistance to collagenase degradation. Crosslinked CSnp on collagen stabilized and enhanced the resistance of dentin matrix against bacterial collagenase degradation due to non-specific interaction with both collagen and collagenase. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Effect of varying polyglutamate chain length on the structure and stability of ferricytochrome c.

    Science.gov (United States)

    Antalík, Marián; Bágel'ová, Jaroslava; Gazová, Zuzana; Musatov, Andrej; Fedunová, Diana

    2003-03-21

    The effect of varying polyglutamate chain length on local and global stability of horse heart ferricytochrome c was studied using scanning calorimetry and spectroscopy methods. Spectral data indicate that polyglutamate chain lengths equal or greater than eight monomer units significantly change the apparent pK(a) for the alkaline transition of cytochrome c. The change in pK(a) is comparable to the value when cytochrome c is complexed with cytochrome bc(1). Glutamate and diglutamate do not significantly alter the temperature transition for cleavage of the Met(80)-heme iron bond of cytochrome c. At low ionic strength, polyglutamates consisting of eight or more glutamate monomers increase midpoint of the temperature transition from 57.3+/-0.2 to 66.9+/-0.2 degrees C. On the other hand, the denaturation temperature of cytochrome c decreases from 85.2+/-0.2 to 68.8+/-0.2 degrees C in the presence of polyglutamates with number of glutamate monomers n >or approximately equal 8. The rate constant for cyanide binding to the heme iron of cytochrome c of cytochrome c-polyglutamate complex also decreases by approximately 42.5% with n>or approximately equal 8. The binding constant for the binding of octaglutamate (m.w. approximately 1000) to cyt c was found to be 1.15 x 10(5) M(-1) at pH 8.0 and low ionic strength. The results indicate that the polyglutamate (n>or approximately equal 8) is able to increase the stability of the methionine sulfur-heme iron bond of cytochrome c in spite of structural differences that weaken the overall stability of the cyt c at neutral and slightly alkaline pH.

  18. Stabilization of red fruit-based smoothies by high-pressure processing. Part A. Effects on microbial growth, enzyme activity, antioxidant capacity and physical stability.

    Science.gov (United States)

    Hurtado, Adriana; Guàrdia, Maria Dolors; Picouet, Pierre; Jofré, Anna; Ros, José María; Bañón, Sancho

    2017-02-01

    Non-thermal pasteurization by high-pressure processing (HPP) is increasingly replacing thermal processing (TP) to maintain the properties of fresh fruit products. However, most of the research on HPP-fruit products only partially addresses fruit-pressure interaction, which limits its practical interest. The objective of this study was to assess the use of a mild HPP treatment to stabilize red fruit-based smoothies (microbial, enzymatic, oxidative and physical stability). HPP (350 MPa/10 °C/5 min) was slightly less effective than TP (85 °C/7 min) in inactivating microbes (mesophilic and psychrophilic bacteria, coliforms, yeasts and moulds) in smoothies kept at 4 °C for up to 28 days. The main limitation of using HPP was its low efficacy in inactivating oxidative (polyphenol oxidase and peroxidase) and hydrolytic (pectin methyl esterase) enzymes. Data on antioxidant status, colour parameters, browning index, transmittance, turbidity and viscosity confirmed that the HPP-smoothies have a greater tendency towards oxidation and clarification, which might lead to undesirable sensory and nutritional changes (see Part B). The microbial quality of smoothies was adequately controlled by mild HPP treatment without affecting their physical-chemical characteristics; however, oxidative and hydrolytic enzymes are highly pressure-resistant, which suggests that additional strategies should be used to stabilize smoothies. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  19. Allee effect: the story behind the stabilization or extinction of microbial ecosystem.

    Science.gov (United States)

    Goswami, Madhurankhi; Bhattacharyya, Purnita; Tribedi, Prosun

    2017-03-01

    A population exhibiting Allee effect shows a positive correlation between population fitness and population size or density. Allee effect decides the extinction or conservation of a microbial population and thus appears to be an important criterion in population ecology. The underlying factor of Allee effect that decides the stabilization and extinction of a particular population density is the threshold or the critical density of their abundance. According to Allee, microbial populations exhibit a definite, critical or threshold density, beyond which the population fitness of a particular population increases with the rise in population density and below it, the population fitness goes down with the decrease in population density. In particular, microbial population displays advantageous traits such as biofilm formation, expression of virulence genes, spore formation and many more only at a high population density. It has also been observed that microorganisms exhibiting a lower population density undergo complete extinction from the residual microbial ecosystem. In reference to Allee effect, decrease in population density or size introduces deleterious mutations among the population density through genetic drift. Mutations are carried forward to successive generations resulting in its accumulation among the population density thus reducing its microbial fitness and thereby increasing the risk of extinction of a particular microbial population. However, when the microbial load is high, the chance of genetic drift is less, and through the process of biofilm formation, the cooperation existing among the microbial population increases that increases the microbial fitness. Thus, the high microbial population through the formation of microbial biofilm stabilizes the ecosystem by increasing fitness. Taken together, microbial fitness shows positive correlation with the ecosystem conservation and negative correlation with ecosystem extinction.

  20. Study on the effect of shape-stabilized phase change materials on spacecraft thermal control in extreme thermal environment

    International Nuclear Information System (INIS)

    Wu, Wan-fan; Liu, Na; Cheng, Wen-long; Liu, Yi

    2013-01-01

    Highlights: ► A shape-stabilized PCM is used to protect the spacecraft attacked by high energy. ► Taking a satellite as example, it proves the solution given in the work is feasible. ► Low thermal conductivity makes the material above its thermal stability limit. ► It provides guidance on how to choose the shape-stabilized PCM for similar problems. - Abstract: In space, the emergencies such as short-term high heat flux is prone to cause spacecraft thermal control system faults, resulting in temperature anomalies of electronic equipment of the spacecraft and even failures in them. In order to protect the spacecraft attacked by the high energy, a new guard method is proposed. A shape-stabilized phase change material (PCM), which has high thermal conductivity and does not require being tightly packaged, is proposed to be used on the spacecraft. To prove the feasibility of using the material on spacecraft attacked by high energy, the thermal responses for spacecraft with shape-stabilized PCM are investigated in situations of normal and short-term high heat flux, in contrast to that with conventional thermal control system. The results indicate that the shape-stabilized PCM can effectively absorb the heat to prevent the thermal control system faults when the spacecraft’s outer heat flux changes dramatically and has no negative effect on spacecraft in normal heat flux. Additionally the effect of thermal conductivity of PCM on its application effectiveness is discussed