Effects Of Relevant Factors Research Articles

Short-Term and Long-Term Mechanical Models of Wellbores Considering Cement Consolidation and Formation Creep

Summary With oil and gas wells extending deeper and deeper, downhole conditions become increasingly complicated, and thus increasingly sophisticated wellbore models are needed. Current wellbore models usually neglect the coupling effect in the cement–consolidation process and do not sufficiently consider the whole operation process of the wellbore. To overcome these shortcomings, short–term and long–term mechanical wellbore models while considering the relevant stages in wellbore life are built. In the short–term model, wellbore–operation stages include casing running, cement displacement, and cement consolidation. The governing equation of cement consolidation while considering the coupling effect between cement hardening and volume change is presented. In the long–term model, the governing equation of formation creep while considering prestresses and initial strains is given. The elastic/viscoelastic–correspondence principle and stress–superposition method are used to simplify the derivation. Next, the effects of relevant factors on short–term and long–term wellbore stresses are analyzed. The results show that wellbore stresses caused by cement consolidation will be underestimated when the coupling effects are neglected. The most vulnerable positions for wellbore failure are on different cylinder elements under different wellbore stages. Wellbore properties, short–term stresses, and formation creep greatly affect wellbore mechanical behaviors. Therefore, the new model provides an important basis for wellbore–failure prediction and optimal design.

Determination of Heat Exchange Rate by A Triangular Heat Generating Conductive Body in an Enclosure Using CFD

This paper performs a numerical analysis of the conjugate heat exchange inside a square enclosure full of a copper-water nanofluid. The enclosure also contains a heat-generating solid triangular block (a source of heat) at the center. While the horizontal walls of the enclosure are viewed as adiabatic, its perpendicular walls are Kept up at a consistently low temperature. The second order upwind scheme is used for convective term and SIMPLE algorithm, to lead the numerical analysis and solve the discrete equations using the commercial software FLUENT15.0. The consequences of the numerical investigations are then used to clear up the effect of relevant factors, e.g. Rayleigh number, solid-volume proportion, thermal conductivity of the source of heat and transfer of heat. The result is accounted in terms of streamlines, isotherms, velocity and temperature profiles over the enclosure, and local and average Nu numbers. As per my findings, the growth of Rayleigh number and the solid volume fraction enhance the thermal performance of the enclosure. At last, the higher thermal conductivity of the source of heat is related to increases in the temperature of the nanofluid in the enclosure, the temperature of the source of heat, and the average Nu.

Experts' and Novices' Perception of Ignorance and Knowledge in Different Research Disciplines and Its Relation to Belief in Certainty of Knowledge.

Assessments of the extent of knowledge in a domain can be important since non-identified lack of knowledge may lead to decisions that do not consider the effect of relevant factors. Two studies examined experts’ and novices’ perception of their own ignorance and knowledge out of everything there is to know within their own and other disciplines and their assessments of their discipline’s, and other disciplines’ knowledge of all there is to know in each discipline. In total 380 experts and 401 students from the disciplines of history, medicine, physics, and psychology participated. The results for ignorance and knowledge assessments of one’s own knowledge were similar. Novices reported more ignorance and less knowledge in their own discipline than experts, but no differences were found in the assessments of how much is known in each discipline. General belief in certainty of knowledge was associated with the knowledge assessments and level of expertise. Finally, disciplinary differences were found both for the knowledge assessments and for belief in certainty of knowledge. Historians and physicists assessed that less was known in their own discipline out of all there is to know (approximately 40%), compared to the medics (about 50%). Historians believed least in certainty of knowledge and physicists most. Our results have practical implications for higher educational teaching and interdisciplinary collaboration.

Predictors of Psychological Evaluation Recommendations in Child Custody and Access Proceedings

Predictors of Psychological Evaluation Recommendations in Child Custody and Access Proceedings Psychologists can make an important contribution to decision making in custody and access proceedings by providing expert opinions to the courts, addressing the best interests of the child. This study aims to investigate quantified effects of indicators on recommendations of psychological evaluators in custody and access proceedings. This data is based on 179 psychological evaluations that were conducted from 2008 to 2012 at an evaluator association in Bremen, Germany. The data is assessed in a quantitative content analysis. Using logistic regression analysis, the influence of child- and parent-related factors on the recommendations of the evaluators is investigated both in custody and in access proceedings. In cases addressing child custody, substance abuse and dependency of the mother and a child's preference for living with the father are significant predictors for the evaluators' recommendation. In cases concerning visitation rights, the child refusing contact with the father and the child experiencing physical abuse are identified as significant predictors. In the present study, the effects of relevant factors on the recommendation of psychological evaluators in family proceedings were first examined on a German sample. This study thus makes an important contribution to the empirical research in the field of psychology and family law.

Kinetic, thermodynamic, optimization and reusability studies for the enzymatic synthesis of a saturated wax ester

Cetyl decanoate was synthesized by esterification reaction catalyzed by immobilized lipase from Thermomyces lanuginosus (TLL) via physical adsorption on poly-(styrene-divinylbenzene) resin (PSty–DVB). The effect of relevant factors on the ester synthesis was evaluated. In this study, a second-order reversible reaction kinetic model was proposed in order to estimate apparent kinetic constants and good agreement with experimental data was observed (0.9430≤R2≤0.9938). The reaction was found to be a spontaneous and endothermic process. The biocatalyst prepared with initial protein loading of 115mg/g of support (immobilized protein concentration of 108.7±3.1mg/g) yielded the highest initial reaction rate (113.5mM/min of reaction), then selected for subsequent tests. The reaction in heptane medium required a slight excess of cetyl alcohol (molar ratio acid:alcohol of 1:1.25) and 7.5% m/m of biocatalyst to attain a maximum conversion of 92.5% for 30min of reaction. In a solvent-free system, maximum conversion of 85.4% was observed for 50min of reaction conducted in an equimolar ratio acid:alcohol and 10% m/m of biocatalyst. The productivity for the reaction performed in heptane medium was higher than in a solvent-free system – 68.5 and 56.4mM/ming of biocatalyst, respectively. The prepared biocatalyst was more active than commercial biocatalysts such as IMMTLL–T2–150 and Lipozyme TL–IM that exhibited maximum conversion around 92% for 45 and 75min of reaction, respectively. The biocatalyst could be reused at least eight times without significant decrease of its activity.

An Acidic Injection Well Technique for Enhancement of the Removal of Copper from Contaminated Soil by Electrokinetic Remediation Process

An experimental study constituting eight different tests was performed to investigate the effect of relevant factors on the remedial efficiency of electro-kinetic process applied to clean-up Cu contaminant from three types of Iraqi soil. An efficiency enhancement scheme was employed involving pH control, acid-injection wells, and optimized potential gradient as part of the investigative program. With pH controlled within the range 2.5-3, four acid-injection wells, and a potential gradient of 0.8 V/cm; overall clean-up efficiencies of 85%, 58%, and 34% were achieved for sandy, sandy loam, and silty loam soils, respectively.

Optimal age replacement policy with replacement occurrence while the warranty is in effect

This study considers an age replacement policy (ARP) for a repairable product with an increasing failure rate with and without a product warranty. As for the warranty policy to consider in association with such an age replacement policy, we adapt a renewable minimal repair-replacement warrant (MRRW) policy with 2D factors of failure time of the product and its corresponding repair time. The expected cost rate during the life cycle of the product is utilized as a criterion to find the optimal policies for both with and without the product warranty. We determine the optimal replacement age that minimizes the objective function which evaluates the expected cost rate during the product cycle and investigate the impact of several factors on the optimal replacement age. The main objective of this study lies on the generalization of the classical age replacement policy to the situation where a renewable warranty depending on 2D factors is in effect. We present some interesting observations regarding the effect of relevant factors based on numerical analysis.

The impact of office workspace on the satisfaction of employees and their overall health - research presentation.

Background : The present article addresses the links between the real-estate factors of the workspace on employee satisfaction and their impact on the overall health of employees. The purpose of the research is to facilitate the improvement of employee health through the application of base parameters, and consequently, the changes of workspace and work processes. The research tests two hypotheses: real-estate factors have a significant impact on employee satisfaction with the workspace; and that satisfaction of employees with the workspace has a significant impact on the overall health of employees. Methodology : We carried out a quantitative research with a broad range of different questions, scales and differentials, whereby the majority of instruments was originally constructed with suitable measurement characteristics. Testing of the questionnaire with the method of internal consistency showed that the questionnaire demonstrates a high level of consistency. The entire questionnaire includes 163 variables divided into content sections: general questions, business building and workspace, workspace design, habits, conditions in the workspace, organisational culture, health care, physical health condition, mental health condition. In July and August 2010, the questionnaire was completed by 1,036 employees from entities in the service sector, i.e. the financial sector, health sector, civil service and others. All the respondents included in the research sample worked in offices. The questionnaire was anonymous in accordance with ethical standards. The results were statistically analysed with the application of factor analysis, which served as a basis for identifying the important factors, while we applied structural equation modelling for verifying the statistically significant mutual effects. Furthermore, we analysed the results and carried out statistical calculations to test the hypotheses. Results : The results show that real-estate factors of the workspace – both in terms of the assessment of business building and position of the employee, as well as the workspace design – have an impact on the satisfaction of employees, and consequently, their assessment of health. On the basis of solutions of structural equation modelling, we established that: the cleanliness of the workspace, lighting of the workspace, orientation of the workspace, regulation of lighting and regulation of air-conditioning in the premises, have a statistically significant impact on the satisfaction of employees with the workspace. With the aid of factor analysis and analysis of the structural equation modelling, as well as in accordance with the set hypotheses, we tested whether the ‘employment satisfaction’ factor affects the ‘overall health’ factor. We established a significant negative link between these two factors. Conclusions : We established a statistically significant impact of real-estate factors of the workspace on the satisfaction of employees, and consequently, the assessment of their overall health. We highlight the need for additional analysis and research of the effect of relevant factors on the health of employees, as well as monitoring thereof through preventive and periodic testing of the health of employees in the work environment.

Comparison of factors affecting injury severity in angle collisions by fault status using a random parameters bivariate ordered probit model

The extant traffic safety research literature includes numerous examples of studies that assess those factors affecting the degree of injury sustained by crash-involved motor vehicle occupants. One important methodological concern in such work is the potential correlation in injury outcomes among occupants involved in the same crash, which may be due to common unobserved factors affecting such occupants. A second concern is unobserved heterogeneity, which is reflective of parameter effects that vary across individuals and crashes. To address these concerns, a random parameters bivariate ordered probit model is estimated to examine factors affecting the degree of injury sustained by drivers involved in angle collisions. The modeling framework distinguishes between the effects of relevant factors on the injury outcomes of the at-fault and not-at-fault parties. The methodological approach allows for consideration of within-crash correlation, as well as unobserved heterogeneity, and results in significantly improved fit as compared to a series of independent models with fixed parameters. While the factors affecting injury severity are found to be similar for both drivers, the magnitudes of these effects vary between the at-fault and not-at-fault drivers. The results demonstrate that injury severity outcomes are correlated for drivers involved in the same crash. Further, the impacts of specific factors may be over- or under-estimated if such correlation is not accounted for explicitly as a part of the analysis. Various factors are found to affect driver injury severity and the random parameters framework shows these effects to vary across crashes and individuals. The analytical approach utilized provides a useful framework for injury severity analysis.

Research on Producing Biodiesel from Waste Oil with 1-Methyl-3-butyl Imidazole Hydroxide Ionic Liquid as a Catalyst

1-Methyl-3-butyl imidazole hydroxide ionic liquid, which was used as a catalyst for producing biodiesel from waste oil, was synthesized and characterized by Fourier transform-infrared spectroscopy and nuclear magnetic resonance spectroscopy. The effects of relevant factors on the transesterification were investigated by a designing orthogonal test. The physicochemical properties of the products were measured and the blending test of the produced biodiesel with 0# diesel was also examined. The experimental results showed that the 1-methyl-3-butyl imidazole hydroxide ionic liquid was a novel highly active and reusable biodiesel production catalyst. The conversion of fatty acid methyl ester reached 95.7% at the optimized reaction conditions of 3 wt% of catalyst addition amount to feed oil, 8:1 alcohol to oil molar ratio, 70°C of reaction temperature, and 110 min of reaction time. The biodiesel product indicated better fluidity at low temperature and high flash point except that the iodine value was a little high. The main physicochemical properties of the product attained to the standard of 0# diesel and the produced biodiesel could be blended with 0# diesel in all proportions before application. The performance of the diesel was improved by blending with the biodiesel.

Thermal Effect on Void Formation of Waxy Crude Oil Using Electrical Capacitance Tomography

Waxy crude oils are commonly found in many parts of the world and represent a huge amount of the global oil reserves. Precipitation of paraffin waxes during various phases creates many problems in the oil industry. Therefore, waxy crude oils create many flow assurance issues essentially linked to them and understanding of the effect of relevant factors and phenomena are of great practical importance. In process industries, the measurement of void fraction is considerably important for sustainable operations and the erroneous calculation could be the cause of many industrial accidents. The customary approach separates the two-phases first and then measures the mixture as individual components. These methods are not favorable as they may result in the disruption of incessant industrial processes. Due to these limitations, this study is aimed to analyze the gel formation behavior of a waxy crude oil under static and dynamic cooling using non-invasive/non-intrusive experimental technique; i.e. Electrical Capacitance Tomography (ECT). This paper describes a fabrication of dual-plane ECT sensor for testing of waxy crude oil at different temperature conditions. ECT images and raw data measurements have been obtained from the two planes are then normalised and then used for image reconstruction. The findings reported in this paper represent part of an ongoing investigation that may lead to develop a cross-correlation between the two planes. The outcome of the study could be used to fully understand the phenomenon of void fraction in waxy crude based on varying the temperature and also based on the design of ECT sensor.

The number of Japanese radiologic technologists will be increased in 40 years

It is essential to predict the long-term supply and demand for the number of radiologic technologists as medical resources. However, it is difficult to predict the number of Japanese radiologic technologists due to complex and intertwining factors. Our purpose in this study was to predict the future number of radiologic technologists using the concept of system dynamics (SD), and to clarify the effects of relevant factors. In order to estimate the number of Japanese radiologic technologists, we constructed a flow diagram using the concept of SD. We simulated the number of radiologic technologists for the following 4 cases: maintaining the status quo, a change in the pass rate for the national examination, a change in the post-graduate employment rate, and a change in the rate of continuing education. The result for the predicted number of radiologic technologists was 50,509 in 20 years, which is 4,394 (9.5%) more than the present number, and 50,166 in 40 years, which is 4,051 (8.8%) more than the present number. For the factors influencing the number of technologists, the influence of the pass rate on the national examination and that of the rate for post-graduate employment was larger than that of the rate of continuing education in graduate school. The number of Japanese radiologic technologists will increase until 2033 and decrease until 2042, and it does not change after 2042 in case of maintaining the status quo. Implementing the concept of SD allowed us easily to clarify the factors influencing the predicted number of radiologic technologists.

Statistical theory for a hydrogen bonding fluid system of A a D d type (IV): Depletion potential between colloid particles

The depletion potential between two colloid particles immersed in a hydrogen bonding fluid has been investigated by density functional theory. The study is motivated by the wide applications of hydrogen bonding fluids in the field of colloid science, and the effects of relevant factors on the depletion potential and depletion force between colloid particles have been studied. These factors include the size ratio of the colloid particle to the fluid molecule, the bulk density of the fluid, the functionality (the number of proton acceptors a and proton donors d) and hydrogen bonding strength as well as the colloid-fluid interaction energy. By comparing the depletion potential calculated under various conditions, it is shown that the effects of these factors on the depletion potential are very significant, and in particular in regulating the depletion force and its range.

English

Information about sweating responses during exercise recovery is insufficient and mostly controversial. In the present study, particular attention is given to sweating behavior at forehead area immediately after exercise. Simultaneous changes of some underlying factors are also addressed. Eight healthy young males (27.4±0.8 years old) volunteered for the study. They performed a constant work rate exercise (60 rpm at 50% of individual work load for VO2 peak) for 30 min. Sweating from the forehead area was measured by the weight gain of a covered filter paper disk. Simultaneous variations in tympanic temperature, heart rate and mean arterial pressure were obtained. Plasma concentrations for sodium, vasopressin, adrenalin and noradrenalin were also determined. Sweating rate increased up to the first sample taken immediately after exercise cessation (P < 0.05). All other variables measured increased during exercise and with exception of noradrenalin, which was maintained high. Other variables, on the whole, decreased during recovery period. At exercise, off-transient coincident with overshoot in sweating rate, tympanic temperature, noradrenalin and vasopressin were subject to a non significant elevation. These results suggest that, sweating from forehead area is still subject to increase at exercise off-transient. The effects of relevant factors studied here are contradictory and could not justify the increase seen in sweating at off-transient. More studies are required to elucidate the causative factor(s).

Analysis of Flowing Characteristics of Abrasive Flow Machining in Slit

Based on the equations of motion and rheological theory of abrasive flow in the slit, effect between wall slip and grinding has been analyzed and grinding flow model of abrasive flow has been built in this paper. Wall pressure, wall shear stress, wall slip and the grinding force equation of abrasive flow were derived using the model. What is important, the effects of relevant factors were analyzed. The results show that wall slip is one of the necessary conditions that in abrasive flow machining, and show that main factors influencing wall slip are viscosity coefficient , grinding coefficient of abrasive flow, and the first normal stress difference. In the meantime, the results also show that grinding force in slit wall is proportional to the entrance pressure of slit. That is to say that the grinding force of per unit length in flow direction increasing dramatically with decreasing slit height.

Optimization of preparation conditions of carboxymethyl potato starch through orthogonal experimental design

AbstractTo optimize the preparation conditions of carboxymethyl potato starch (CMPS), the effects of relevant factors on viscosity (η) of 2% CMPS aqueous solution and degree of substitution (DS) were investigated. These condition parameters included etherification temperature, alkalization and etherification time, water content in the mixed solvent, ratio of liquid volume to starch mass, molar ratio of sodium hydroxide to monochloroacetic acid, and molar ratio of monochloroacetic acid to anhydroglucose unit. After individual parameter influencing η and DS was researched one by one, an orthogonal experiment of L18 (2 × 37) was designed to identify the main factors affecting them. In light of range analysis, the comparative importance of factors impacting η and DS was obtained, separately. Results of variance analysis showed that the most effective factor to control DS was etherification temperature, whereas the influences of all factors on η were not significant. Meanwhile, η and DS of the optimized final product were found to be 12,000 mPa.s and 0.68, respectively. In addition, the structure of CMPS was characterized by Fourier transform infrared (FTIR) spectrophotometer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

β-Carotene removal from soybean oil with smectite clay using central composite design

In this study removal of β-carotene from soybean oil by adsorption on acid activated smectite clay from Serbia was investigated and a factorial 23 experimental design was applied. The effects of relevant factors, such as temperature, solid-to-liquid ratio and time, on removal of β-carotene were investigated. In order to check these factors and their effect on the removal of β-carotene, we have established a model of this technique following a methodological strategy using experiments design. The mathematical model is established using a central composite design. The model describes the changes of the measured responses of β-carotene removal efficiency according to the temperature, solid-to-liquid ratio and time. The graphical representation of this model in the space of the variables enabled us to define the optimum conditions of these parameters. The optimum conditions to obtain the maximum removal of β-carotene from soybean oil were a temperature of 80°C, a solid-to-liquid ratio of 1: 25 and a time of 1255 s. Under these optimal conditions, the experimental values agreed with the predicted values, using analysis of variance, indicating a high goodness of fit of the model used and the success of response surface methodology for optimizing adsorption β-carotene of acid activated smectite clay from soybean oil.

Synthesis and characterization of acid-activated Serbian smectite clays obtained by statistically designed experiments

Abstract Statistically designed experiments were done to study the recovery of Mg content from natural smectite clays from Serbia by hydrochloric acid leaching. The effects of relevant factors, such as temperature, leaching time, acid normality, solid-to-liquid ratio and stirring rate on leaching yield of MgO have been investigated. Experiments have been planned by the factorial design method. To test the significance of the effects, an analysis of variance has been conducted at 95% confidence intervals. The structural and adsorption properties of the starting smectite clay and the sample activated at chosen conditions were investigated by means of a model. Scanning electron microscopy (SEM) and nitrogen adsorption–desorption were used to analyze the morphological characteristic of the starting and the activated sample. The results from the nitrogen adsorption–desorption isotherms show that the activated smectite clay possess a narrow pore size distribution of about 2 nm, and a large specific surface area of 238 m2/g. The results of X-ray diffraction (XRD) and infrared analysis (IR) of starting and activated samples confirmed that smectite was the dominant mineral phase. Besides, chemical treatment of smectite clay with HCl produces an adsorbent with optimal porosity and other adsorption properties suitable for many industrial processes.

Affective affordances: Improving interface character engagement through interaction

The nature of humans interacting with interface characters (e.g. embodied agents) is not well understood. The I-PEFiC model provides an integrative perspective on human–character interaction, assuming that the processes of engagement and user interaction exchange information in explaining user responses with interface characters. An experiment using the Sims2 game was conducted to test the effects of aesthetics (beautiful versus ugly, as engagement factor) and affordances (help versus obstacle, as interaction factor) of interface characters on use intentions, user engagement, and user satisfaction. Results of the experiment showed that (1) people tended to use helpful characters more than obstructing characters, (2) user engagement was enhanced by beauty and perceived affordance of the character whereas (3) intentions to use the character were not affected by good looks, and (4) the most satisfied users were those that were engaged with the character as well as willing to use it. This stresses the importance of enhancing affordances so to increase user engagement with interface characters. The I-PEFiC model provided a valuable framework to study the (interdependent) effects of relevant factors in human–character interaction.

Study on sensing properties of tin oxide CO gas sensor with low power consumption

In this paper, the fabrication method of a new type of carbon monoxide gas sensor based on SnO x with low power consumption and its sensing characteristics have been reported. The electric conductance of this type of sensor evolves oscillation form regularly when the sensor is exposed to low level of CO gas. The oscillation amplitude is directly proportional to the concentration of CO gas over a wide range. The effects of relevant factors, such as, humidity, temperature and interference gases on the sensor properties were examined. The sensing oscillation response mechanism was also discussed.