Average Ones Research Articles

Effect of viscoelastic relaxation modes on stability of extrusion film casting process modeled using multi-mode Phan-Thien-Tanner constitutive equation

• Linear stability analysis of film casting using multimode PTT model. • Addition of faster moving modes to a slower one enhances stability of the process. • Stability regions of multimodes to not match well with the corresponding averaged ones. Extrusion film casting (EFC) is a commercially important process that is used to produce a significant quantity of polymer films, sheets and coatings for both industrial and household applications. Recently, we have demonstrated the influence of polymer chain architecture on the extent of necking under isothermal as well as non-isothermal film casting operation for commercially relevant polyolefin based materials [1] , [2] , [3] , [4] . In the present research, we focus on another instability that frequently occurs in high-speed EFC process called as draw resonance. Draw resonance manifests itself as an instability that causes periodic fluctuations in both the width as well as thickness of the extruded molten film above a critical draw ratio (DR). In this work, we have carried out a linear stability analysis of the isothermal EFC process using a multi-mode Phan-Thien-Tanner (PTT) constitutive equation to determine the onset of draw resonance. We show that as the number of relaxation modes is increased there is a dramatic change in the stability regions. In particular, there is a marked variation in the stability regions obtained by simulating the multi-mode model and those obtained by taking averaged relaxation time of the modes. Additionally, as the number of faster-relaxing modes in a multi-mode spectrum is progressively increased, the process becomes increasingly stable as the level of elasticity in the melt decreases. Finally, the addition of a long relaxation mode in a multi-mode spectrum is akin to adding a long chain branch to a linear polymer that leads to a reduction in film necking and in many cases to enhanced process stability.

Lateral variation in seismic velocities and rheology beneath the Qinling-Dabie orogen

The Qinling-Dabie orogen is an important tectonic belt that trends east-west and divides continental China into northern and southern parts. Due to its strong deformation, complicated structure, multiphase structural superposition and the massive exposed high and ultrahigh metamorphic rocks, its tectonic formation and geodynamical evolution are hot research topics worldwide. Previous studies mainly focused on the regional geological or geochemical aspects, whereas the geophysical constraints are few and isolated, in particular on the orogenic scale. Here, we integrate the available P- and S-wave seismic and seismicity data, and construct the rheological structures along the Qinling-Dabie orogen. The results demonstrate that: (1) there are strong lateral variations in the crustal velocity between the western and eastern sections of the Qinling-Dabie orogen, indicating the different origin and tectonic evolution between these two parts; (2) the lateral variations are also manifested in the rheological structure. The rigid blocks, such as South China and Ordos basin (North China Craton), resist deformation and show low seismicity. The weak regions, such as the margin of Tibet and western Qinling-Dabie experience strong deformation and accumulated stress, thus show active seismicity; (3) in the lower crust of most of the HP/UHP terranes the values of P-wave velocity are higher than the global average ones; finally (4) low P- and S-wave velocities and low strength in the lower crust and lithospheric mantle beneath Dabie indicate lithospheric delamination, and/or high temperature, and partial melting condition.

Prejudicial and Stereotypical Attitudes about the Issue of Obesity: An Action Project

Scientific literature about stereotypical and prejudicial attitudes toward obese people indicates rejection toward the obese individuals and preferences toward thin and average ones, as well as a stereotypical profile that attributes to obese people traits such as weakness, laziness, and sickness, while to thin and average people characteristics as beauty, strength, health, and successfulness (Tiggemann & Anesbury, 2000; Carels & Musher-Eizenman, 2010). One of the most useful strategies for reducing the effects of negative prejudices and stereotypes toward the obesity and obese people is constituted by contact, achievable both in face to face and imagined setting. Purpose: analysis of the exposure effects to stimuli (training course about prejudice on obesity) functional to reduce negative attitudes toward obese people. Participants: 55 psychology university students at University of Catania, Sicily (Italy). Implicit and explicit measures: 1) Anti-fat Attitudes and Dislike of Fat People Scale; 2) Semantic Differential Technique for Fat and Thin People Representation and Physical Self; 3) Fat Stereotypes Questionnaire; 4) GNAT (Nosek & Banaji, 2001). All measures were used before and after the training course (for three months) about the “obesity issue”. Results (before-after the training course): a) low levels of anti-fat prejudice and of dislike of fat people; b) absence of change of fat stereotypes; c) significant increase in fat and thin people positive representation, as well as in self-representation; d) significant effects of the training course only in relation to an increase of accuracy in the GNAT application. Future suggestions regarding to the effects of the direct and imagined contact with obese people functional to reduce negative attitudes toward these target were discussed.

Attractiveness of the female body: Preference for the average or the supernormal?

The main purpose of the present study was to contrast the two hypotheses of female body attractiveness. The first is the ?preference-for-the average? hypothesis: the most attractive female body is the one that represents the average body proportions for a given population. The second is the ?preference-for-the supernormal? hypothesis: according to the so-called ?peak shift effect?, the most attractive female body is more feminine than the average. We investigated the preference for three female body characteristics: waist to hip ratio (WHR), buttocks and breasts. There were 456 participants of both genders. Using a program for computer animation (DAZ 3D) three sets of stimuli were generated (WHR, buttocks and breasts). Each set included six stimuli ranked from the lowest to the highest femininity level. Participants were asked to choose the stimulus within each set which they found most attractive (task 1) and average (task 2). One group of participants judged the body parts that were presented in the global context (whole body), while the other group judged the stimuli in the local context (isolated body parts only). Analyses have shown that the most attractive WHR, buttocks and breasts are more feminine (meaning smaller for WHR and larger for breasts and buttocks) than average ones, for both genders and in both presentation contexts. The effect of gender was obtained only for the most attractive breasts: males prefer larger breasts than females. Finally, most attractive and average WHR and breasts were less feminine in the local than in the global context. These results support the preference-for the supernormal hypothesis: all analyses have shown that both male and female participants preferred female body parts which are more feminine than those judged average.

Playing with Vincent-the-Duck in the work space: physical, playful artefacts as totems of organizational symbolism

Physical artifacts represented often in the form of animals, are used to symbolize and reinforce organizational culture. There is a difference between strong and successful organizations and the average ones, and we think the reason for this lies in how culture is expressed in visible daily routines in a unique and in playful way. Let us tell you a short story about Vincent-the-Duck. Vincent was born in an IT-Technology company almost ten years ago. Vincent’s job is to sit next to the computer table or a screen and to “be wise”. People use Vincent when they have a problem; he gives people an easy way to find a solution and to ask questions. We see walking and talking people in the meeting rooms with Vincent. They don´t need to bother any of their colleagues. Furthermore, Vincent has another role to function as a special symbol for the company; his picture is everywhere and he is celebrated in many ways. Until now. There are only few studies in organization theory regarding the physical artifacts. Images and visual artifacts are not just add-ons to verbal texts, mere transmitters of information, or means of communication: they have become an elementary mode for the construction, maintenance and transformation of meaning. Various scholars have taken up the challenge of including aspects related to visuality in their empirical research as well as in theory building. (Meyer et al. 2013, p. 490–491). We use the example of Vincent-the-Duck – an actual physical artefact symbolizing company X as a point of departure to examine how physical, playful artifacts may be used to reinforce organizational culture. Thus, we aim to find out how organizations can use tangible and physical objects to reinforce their culture and way of working? and What kind of stories are behind tangible objects, which are used to enhance organization identity? This study is based on aesthetics approach, which examines the artefact in its “beginning-in-use” in organizational settings, emphasizing material knowledge and practice in the study of organizations. Everyday organizational routine comprises artifacts that are beautiful to use, graceful to the eye or grotesque, kitsch or repellent and to which the language-in-use of organizational discursive practices attaches labels evocative of the aesthetic categories of beautiful, ugly, sublime, gracious and so on. There are artifacts that are desirable or repulsive, artifacts born from our desire for knowledge, and artifacts that spring from our desire to give form in that every human forms something. (Strati 2013, p. 25–26.) The data analysis is still on going and the results are tentative, but nevertheless, our analysis indicates that physical artefacts rare important in symbolizing and reinforcing organizational culture. Our study combines how organizational members use physical playful artifacts to construct an organizational phenomenon in the form of a totem.

Natural radioactivity investigation in Dam sediments of northeast Algeria using gamma spectroscopy

Current research paper intends to estimate the natural radioactivity levels in sediments samples collected from Beni Haroun Dam in the northeast Algeria, using high resolution HPGe detector. The mean activity concentrations values measured for the radionuclides 232Th, 226Ra and 40K are 18.9 ± 1.9, 37.3 ± 2.7 and 149.9 ± 5.5 Bq/kg, respectively. The 137Cs anthropogenic radionuclide has been observed with maximum activity concentration value of 0.8 ± 0.4 Bq/kg, which is considered an insignificant amount. In order to assess the radiological threat of gamma radiations emitted by these radionuclides on the health of the population, absorbed dose rate, annual effective dose equivalent and radiation hazard indices were had been calculated. The obtained values are compared with the world wide average ones.

On the Relationship Between Confidence Sets and Exchangeable Weights in Multiple Linear Regression

ABSTRACTWhen statistical models are employed to provide a parsimonious description of empirical relationships, the extent to which strong conclusions can be drawn rests on quantifying the uncertainty in parameter estimates. In multiple linear regression (MLR), regression weights carry two kinds of uncertainty represented by confidence sets (CSs) and exchangeable weights (EWs). Confidence sets quantify uncertainty in estimation whereas the set of EWs quantify uncertainty in the substantive interpretation of regression weights. As CSs and EWs share certain commonalities, we clarify the relationship between these two kinds of uncertainty about regression weights. We introduce a general framework describing how CSs and the set of EWs for regression weights are estimated from the likelihood-based and Wald-type approach, and establish the analytical relationship between CSs and sets of EWs. With empirical examples on posttraumatic growth of caregivers (Cadell et al., 2014; Schneider, Steele, Cadell & Hemsworth, 2011) and on graduate grade point average (Kuncel, Hezlett & Ones, 2001), we illustrate the usefulness of CSs and EWs for drawing strong scientific conclusions. We discuss the importance of considering both CSs and EWs as part of the scientific process, and provide an Online Appendix with R code for estimating Wald-type CSs and EWs for k regression weights.

Regional Differences Assessment in the Level of Economic Development and Life Quality

The main purpose of this article is to examine theoretical and methodological framework for assessing the differences in the level of economic development and quality of life in the regions.The study of existing approaches to the regional classification led to a conclusion of insufficient use of opportunities in the comparative analysis of such research angles as comparison at the federal level and examination of the situation in the territory in dynamics to determine the rates of change of the measured indicators.In connection with this, the author elaborated a method of static and dynamic analysis of differences in the level of economic development and quality of life based on the developed system of indicators, and formed a typology of regions on the basis of this system.The typology involves the division of territories into four clusters according to their level of development under static conditions (in absolute terms at the Russian level) and in dynamics (in relative terms at the national level).The end of the article presents the results of application of this method in the Siberian Federal District (SFD) (analytical framework for 2003-2013), according to which the social and economic indicators of the SFD fall significantly behind the national average ones under static conditions, but have higher dynamic estimates.In some regions, the situation varies considerably.The article also contains the methodology for determining the relationship between indicators of the level of economic development and quality of life to assess the impact of the crisis on satisfaction of the population needs.

Influence of trabecular microstructure modeling on finite element analysis of dental implant

To analyze the influence of trabecular microstructure modeling on the biomechanical distribution of implant-bone interface with a three-dimensional finite element mandible model of trabecular structure. Dental implants were embeded in the mandibles of a beagle dog. After three months of the implant installation, the mandibles with dental implants were harvested and scaned by micro-CT and cone-beam CT. Two three-dimensional finite element mandible models, trabecular microstructure(precise model) and macrostructure(simplified model), were built. The values of stress and strain of implant-bone interface were calculated using the software of Ansys 14.0. Compared with the simplified model, the precise models' average values of the implant bone interface stress increased obviously and its maximum values did not change greatly. The maximum values of quivalent stress of the precise models were 80% and 110% of the simplified model and the average values were 170% and 290% of simplified model. The maximum and average values of equivalent strain of precise models were obviously decreased, and the maximum values of the equivalent effect strain were 17% and 26% of simplified model and the average ones were 21% and 16% of simplified model respectively. Stress and strain concentrations at implant-bone interface were obvious in the simplified model. However, the distributions of stress and strain were uniform in the precise model. The precise model has significant effect on the distribution of stress and strain at implant-bone interface.

MILP-Based Dynamic Efficiency Scheduling Model of Battery Energy Storage Systems

This paper presents a methodology to determine an optimal operation schedule of a battery energy storage system (BESS) considering dynamic charging/discharging efficiencies considering the output power levels. A novel optimization problem is formulated based on the mixed integer linear programming (MILP) addressing a non-linear charging/discharging efficiency function by a stair-wise linear model. Technical constraints of BESS are also included in the MILP formulation. Test simulation results of BESS operation for the two Korean power systems show the effectiveness of the dynamic efficiency scheduling model compared to the conventional average efficiency ones.

Signal-to-noise ratio improvements in laser flow diagnostics using time-resolved image averaging and high dynamic range imaging

Two alternative image readout approaches are demonstrated to improve the signal-to-noise ratio (SNR) in temporally resolved laser-based imaging experiments of turbulent phenomena. The first method exploits the temporal decay characteristics of the phosphor screens of image intensifiers when coupled to an interline-transfer CCD camera operated in double-frame mode. Specifically, the light emitted by the phosphor screen, which has a finite decay constant, is equally distributed and recorded over the two sequential frames of the detector so that an averaged image can be reconstructed. The characterization of both detector and image intensifier showed that the technique preserves the correct quantitative information, and its applicability to reactive flows was verified using planar Rayleigh scattering and tested with the acquisition of images of both steady and turbulent partially premixed methane/air flames. The comparison between conventional Rayleigh results and the averaged ones showed that the SNR of the averaged image is higher than the conventional one; with the setup used in this work, the gain in SNR was seen to approach 30 %, for both the steady and turbulent cases. The second technique uses the two-frame readout of an interline-transfer CCD to increase the image SNR based on high dynamic range imaging, and it was tested in an unsteady non-reactive flow of Freon-12 injected in air. The result showed a 15 % increase in the SNR of the low-pixel-count regions of an image, when compared to the pixels of a conventionally averaged one.

Speed control of oil-hydraulic power take-off system for oscillating body type wave energy converters

The variable displacement oil-hydraulic pumps for the Power Take-Off (PTO) of wave energy converters must work above 80% of maximum displacement in order to have an overall efficiency of approximately 94.5%. This is achieved by controlling their rotational speed when the oil-hydraulic power fluctuates in time. Three speed control strategies have been presented, the first fixing the maximum possible speed in each sea state, the second by slowly varying the pump speed between speed peak values and average ones, and the third by working with highly variable speed reference values. The worst pump efficiency is achieved with the first strategy while the best one with the third strategy. However, the first has less impact than the third one in the pump lifecycle. On the other hand, the second strategy is used to make a trade-off between pump efficiency and lifecycle. However, this paper presents a fourth speed control strategy, which is a hybrid of the second and third strategies. So, the objectives of this paper were to know if these strategies are implementable in a test rig and also on a new PTO concept and determining what modifications should be introduced in these PTO strategies and hardware. This paper also contributes with the application of new methodologies in this field of research for the modelling of pump efficiency and pressure control, such as Neuro-Fuzzy modelling and Fuzzy Logic control systems.

Determination of the elastic moduli and residual stresses of freestanding Au-TiW bilayer thin films by nanoindentation

In this paper, we present a detailed mechanical characterization of freestanding bilayer (Au-TiW) micro-cantilevers and double clamped beams, for applications as Radio Frequency (RF)-switches Micro-Electromechanical Systems (MEMS). The testing structures have been characterized by an optical profilometer and Scanning Electron Microscopy (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDS), in order to acquire information about their geometries, composition, and the gap between the substrate underneath. Then, the micro-beams are deflected by using a specifically designed nanoindentation procedure based dynamic stiffness measurement during bending in order to extract the elastic modulus and the residual stresses of both layers. Firstly, the classic beam theory has been implemented for bilayer cantilevers enabling the extraction of elastic moduli. Then, residual stresses are estimated by deflecting double clamped beams, while implementing new analytical models for a bilayer system. The obtained elastic moduli are consistent with the average ones obtained for a single layer micro-cantilever and with nanoindentation results for TiW and Au homogeneous films. The residual stresses are in agreement with the values obtained from the double slot Focused Ion Beam (FIB) and Digital Image Correlation (DIC) procedure, providing an alternative and portable way for the assessment of residual stresses on composite double clamped micro-beams.

Variability of energy woodchips and their economic effects

Abstract The main aim of the work is to assess physical parameters of forest woodchips and their impact on the prices achieved by the supplier in transactions with a power plant. During fragmentation of logging residue, high content of green matter and contaminants negatively impacts the quality parameters that serve as basis for settlements. The analysis concerns data on the main parameters - water content, fuel value, sulphur and ash content - from 252 days of deliveries of forest chips to a power plant. The deliveries were realised from forested areas on an average about 340 km from the plant. Average water content and the resultant fuel value of forest chips was within 27-47% and 8.7-12.9 GJ×Mg-1 (appropriately), respectively. They depend on the month in which they are delivered to the power plant. The threshold values for the above-mentioned parameters are set by the plant at a real level and the suppliers have no problems with meeting them. The parameter that is most frequently exceeded is ash content (11.5% of cases). The settlement system does not differentiate on the basis of the transport distance but gives possibility to lower the settlement price when the quality parameters are not met but provides no reward for deliveries with parameters better than the average ones. On the basis of results obtained, it was calculated that average annual settlement price is lower than the contract price by about 0.20 PLN×GJ-1, which in case of the analysed company may translate into an average daily loss of about 700 PLN.

Modeling Project Manager Competency: An Integrated Mathematical Approach

AbstractAlthough the construction industry is a major component of the U.S. economy, it has been suffering from declining productivity for decades. The human element, project managers (PMs) in particular, are key in solving these persisting problems. Measurement of a PM’s overall performance is important to identify training needs and enables executives to better match competent PMs with the appropriate projects. This paper provides the construction industry with a generic mathematical formulation to reliably weigh different PM competencies. The developed data-driven mathematical model reflects the relative importance that industry practitioners place on different PM competencies while distinguishing exceptional PMs from average ones. This developed model is applied to a data set of 124 PM assessments filled by 62 PM supervisors so that each PM supervisor selected and rated an exceptional PM and an average PM. The results presented in the paper suggest that PMs should focus on developing their cognitive s...

A scale‐free network model for HIV transmission among men who have sex with men in China

Objective: The study aimed to analyze sexual networks and sex role preference as factors of HIV transmission among men who have sex with men (MSM) in China.Methods: We have developed a new scale‐free network model with a sex role preference framework to study HIV transmission among MSM. We have studied the influence of different sexual networks and the effect of different proportion of sex role preference upon HIV transmission. The results are that the average ones drawn from the scenarios have been simulated for more than 30 times.Results: Compared with the traditional mathematical model, the sexual networks provide a different prediction of the HIV transmission in the next 30 years. Without any intervention, the proportion of HIV carriers will descend after some time.Conclusions: There is significant associations among network characteristics, sex role preference, and HIV infection. Although network‐based intervention is efficient in reducing HIV transmission among MSM, there are only few studies of the characteristics of sexual network, and such gaps deserve more attention and exploration. Copyright © 2016 John Wiley & Sons, Ltd.

Objective Assessment of Nuclear and Cortical Cataracts through Scheimpflug Images: Agreement with the LOCS III Scale.

PurposeTo assess nuclear and cortical opacities through the objective analysis of Scheimpflug images, and to check the correlation with the Lens Opacity Classification System III (LOCS III).MethodsNuclear and cortical opacities were graded according to the LOCS III rules after pupil dilation. The maximum and average pixel intensity values along an elliptical mask within the lens nucleus were taken to analyse nuclear cataracts. A new metric based on the percentage of opaque pixels within a region of interest was used to analyse cortical cataracts. The percentage of opaque pixels was also calculated for half, third and quarter areas from the region of interest’s periphery.ResultsThe maximum and average intensity values along the nucleus were directly proportional to the LOCS III grade: The larger the LOCS III value, the larger maximum and average intensity ones. These metrics showed a positive and significant correlation with the LOCS grade: The larger the LOCS grade, the higher was percentage of opaque pixels along the cortex within the same mask’s size. This metric showed a significant correlation to the LOCS grade.ConclusionThe metrics used to assess nuclear opacities showed good correlation with the LOCS III. The percentage of opaque pixels showed to be a useful metric to measure objectively the severity of the cortical opacity. These metrics could be implemented in an algorithm to detect and grade lens opacities automatically and objectively.

Activities of 232Th, 226Ra, 40K, and 137Cs in surface soil and external dose assessment at two zones of Buenos Aires Province, Argentina

In the frame of establishing the radiological baseline of the Buenos Aires Province, Argentina, this work assesses the total outdoor external dose and the activity values of 40K, 226Ra, 232Th and 137Cs in superficial soils of La Plata and Lima cities. In the latter, the most important nuclear emplacement of the country is located. At La Plata, 49 sites were analyzed, which correspond to the green public spaces of the city while at Lima 6 sites around the nuclear power plants were studied. For La Plata, the external dose contribution and activity distribution maps of 40K, 226Ra, 232Th and 137Cs were obtained using the Kriging geo-statistical method. Activity values of 226Ra and 232Th resulted lower than their worldwide average ones, while the 40K levels were higher than the corresponding one. The activity dataset was analyzed together with the activity values determined previously in unperturbed soils of the region. The Pearson correlation coefficient was re-calculated, obtaining correlations more significant when all activity data were considered. No correlation between activity superficial distributions and the height above sea level or the geomorphological units was found. The activity values obtained in Lima soils lie in the range of the values determined for La Plata soils. Like in La Plata, 137Cs activity around the nuclear facility could be associated only with the nuclear power tests. The average total external annual dose for La Plata inhabitants are in the range of 0.19 to 0.25 mSv/year, similar to those determined for Lima residents. The present work complements previous reports contributing to the establishment of the radiological baseline for soils of Buenos Aires Province, Argentina, the province with the most important nuclear activities of the country.

Schema Theorem Based on Probability for Multigenic Chromosomes Genes Expression Programming

Schema theorem is the theoretical foundation of the evolutionary algorithm. This paper focuses on a new, and general schema theory for multigenic chromosomes gene expression programming. The theory is applicable to every operator in GEP via the method of probability. Not only the destruction but also the creation probability of the schema is considered in the evolutionary process. An equivalent form of general schema theory of GEP was deduced. The result shows that the individuals with high fitness values, shorter schema order, more function nodes, and the shorter the insertion sequence have the greater transmission probability than the average ones.

Smart Control of Air Climatization System in Function on the Values of Mean Local Radiant Temperature

The hygrothermal comfort indoor conditions are defined as: those environmental conditions in which an individual exposed, expresses a state of satisfaction. These conditions cannot always be achieved anywhere in an optimal way and economically; in some cases they can be obtained only in work environments specific areas. This could be explained because of air conditioning systems designing is generally performed both on the basis of the fundamental parameters’ average values, such as temperature, velocity and relative humidity (T a , v a e φ a ) and derived parameters such as operating temperature and mean radiant one (T op eT mr ). However, in some specific cases - large open-spaces or in case of radiating surfaces - the descriptors defining indoor comfort conditions, based on average values, do not provide the optimum values required during the air conditioning systems design phase. This is largely due to the variability of real environmental parameters values compared to the average ones taken as input in the calculation. The results obtained in previous scientific papers on the thermal comfort have been the driving element of this work. It offers a simple, original and clever way of thinking about the new domotic systems for air conditioning, based on the “local mean radiant temperature.” This is a very important parameter when one wants to analyze comfort in environments characterized by the presence of radiating surfaces, as will be seen hereinafter. In order to take into account the effects of radiative exchanges in the open-space workplace, where any occupant may find themselves in different temperature and humidity conditions, this paper proposes an action on the domotic climate control, with ducts and vents air distribution placed in different zones. Comparisons were performed between the parameters values representing the punctual thermal comfort, with the Predicted Mean Vote PMV, in an environment marked by radiating surfaces (i.e continuous glass) and calculated with the local radiant temperature suggested in previous works, with the corresponding values obtained always varying the air speed or the air temperature inflated from the air vents, in order to achieve the optimal comfort conditions.