Prime Variables Research Articles

Purification of reduced upgraded titania slag by iron removal using mild acids

In this study, we focused on removal of iron from upgraded titania slag (UGS) that has been reduced by hydrogen gas, magnesium powder and salts at 750°C for 5h. Reduced UGS is mainly composed of titanium hydride and oxide impurities that include iron, silicon, aluminum, and magnesium. Mild concentrations of hydrochloric and boric acids were used in this investigation to remove iron from reduced UGS. The concentration of hydrochloric and boric acids and the leaching temperature have been chosen as the prime variables to identify the optimum conditions and leaching characteristics for purification of reduced UGS. Both ambient pressure leaching and elevated pressure leaching were performed to assess the rate of iron removal from reduced UGS without titanium loss. It was observed that under the constraint that 1% (w/w) of titanium hydride loss is the maximum amount tolerable, 0.1M hydrochloric acid at 140°C was found to be the most effective conditions for iron removal (87.63%). A factorial design of experiment for equation modeling with three main factors (temperature, concentration of hydrochloric and boric acids) was performed and associated modeling results were in good agreement with experimental data. The overall rate of reaction seems to follow interfacial reaction controlled kinetics. The calculated activation energy of the reaction is 73.9kJ/mol.

One Diophantine inequality with integer and prime variables

In this paper, we show that if $\lambda_{1}$ , $\lambda_{2}$ , $\lambda_{3}$ , $\lambda_{4}$ are positive real numbers, at least one of the ratios $\lambda_{i}/\lambda_{j}$ ( $1\leq i< j\leq4$ ) is irrational, then the inequality $|\lambda_{1}x_{1}^{2}+\lambda_{2}x_{2}^{3}+\lambda_{3}x_{3}^{4} +\lambda_{4}x_{4}^{5}-p-\frac{1}{2}|<\frac{1}{2}$ has infinite solutions with natural numbers $x_{1}$ , $x_{2}$ , $x_{3}$ , $x_{4}$ and prime p.

Panel zone deformation demands in steel moment resisting frames

Energy is dissipated by yielding at beam ends in steel moment resisting frames subjected to earthquakes. In addition, the column panel zone can be proportioned to participate in energy dissipation. AISC360, Eurocode 3, and FEMA-355D specifications have different philosophies for the design of panel zones which lead to different amounts of deformation demands. This paper presents a numerical study undertaken to quantify the deformation demands in panel zones proportioned according to different specifications. Pursuant to this goal, the panel zone design requirements of three specifications were compared first to identify differences and similarities. A parametric study was conducted by considering the beam depth, axial load level on columns, thickness of panel zone, and seismic hazard as the prime variables. Archetypes were analyzed by employing three-dimensional explicit nonlinear finite element time history analyses. The analysis results revealed that designs according to AISC360 and Eurocode 3 resulted in significant amounts of yielding of the panel zone while the designs according to FEMA 355D resulted in minimal amount of yielding. The panel zone deformation demands were quantified and an equation used to estimate the deformation levels was developed herein.

On Lagrange’s four squares theorem with almost prime variables

Abstract In 1994, Brüdern and Fouvry [1] initiated the investigation of Lagrange’s four squares theorem with almost prime variables. In this paper, we prove that every sufficiently large integer, congruent to 4 modulo 24, can be represented as a sum of four squares of integers, each of which has at most four prime factors. Instead of the four-dimensional vector sieve developed by Brüdern and Fouvry [1], we establish this result by combining the three-dimensional sieve and the switching principle.

Displacement amplification factors for steel eccentrically braced frames

SummaryInelastic deformation capacity of links is a factor that significantly influences design of steel eccentrically braced frames (EBFs). The link rotation angle is used to describe inelastic link deformation. The link rotation angle is generally calculated by making use of design story drifts that in turn are calculated by modifying the elastic displacements by a displacement amplification factor. This paper presents a numerical study undertaken to evaluate the displacement amplification factor given in ASCE7‐10 for EBFs and the rigid‐plastic mechanism used for calculating link rotation angles. A total of 72 EBFs were designed by considering the number of stories, the bay width, the link length to bay width ratio, and the seismic hazard level as the prime variables. All structures were analyzed using elastic and inelastic time history analyses. The results indicated that the displacement amplification factor given in ASCE7‐10 provides unconservative estimates of the story drifts. On the other hand, the rigid‐plastic mechanism provides conservative estimates of link rotations. Based on the results of the numerical study, a new set of displacement amplification factors that vary along the height of the structure and modifications to the rigid‐plastic mechanism were developed. In light of the proposed modifications, the EBFs were redesigned and analyzed using inelastic time history analysis. The results indicated that the proposed modifications provide improvements for the displacement amplification factor and link rotation angle calculation procedures. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Spatial prediction of soil water content in karst area using prime terrain variables as auxiliary cokriging variable

In karst areas, accurately measuring and managing the spatial variability of soil water content (SWC) is very critical in settling numerous issues such as karst rocky desertification, ecosystem reconstruction, etc. In these areas, SWC exhibits strong spatial dependence, and it is a time and labor consuming procedure to measure its spatial variability. Therefore, estimation of this kind of soil property at an acceptable level of accuracy is of great significance. This study was conducted to evaluate and compare the spatial estimation of SWC by using ordinary kriging (OK) and cokriging (COK) methods with prime terrain variables, tending to predict SWC using limited available sample data for a 2,363.7 km2 study area in Mashan County, Guangxi Zhuang Autonomous Region, Southwest China. The measured SWC ranged from 3.36 to 26.69 %, with a mean of 17.34 %. The correlation analysis between SWC and prime terrain variables indicated that SWC showed significantly positive correlation with elevation (r is 0.46, P < 0.01), and significantly negative correlation with slope (r is −0.30, P < 0.01); however, SWC was not significantly correlated with aspect in the study area. Therefore, elevation and slope were used as auxiliary data together for SWC prediction using COK method, and mean error (ME) and root mean square error were adopted to validate the prediction of SWC by these methods. Results indicated that COK with prime terrain variables data was superior to OK with relative improvement of 28.52 % in the case of limited available data, and also revealed that such elevation and slope data have the potential to improve the precision and reliability of SWC prediction as useful auxiliary variables.

Fundamental periods of steel eccentrically braced frames

SummaryThis paper describes formulation of a hand method that can be used to estimate the computed fundamental periods of vibration of building structures in general and steel eccentrically braced frames (EBFs) in particular. The developed method uses the Rayleigh's method as a basis and utilizes the roof drift ratio (RDR) under seismic forces as a parameter. To obtain RDR, more than 4000 EBFs were designed by considering the seismic hazard, number of stories, braced bay width and link length to bay width ratio as prime variables. A model was developed to estimate RDR, which depends on the rigid plastic deformation mechanism for a typical EBF. The method was verified using design data produced as a part of this work as well as data published in literature. The verifications indicate that the proposed formulation is capable of providing acceptable estimates of the computed period. When compared with existing empirical period–height relationships, the proposed formulation offers closer estimates with reduced scatter. The method was further refined to derive new period–height relationships for two different seismicity regions. The accuracy of the relationship for high seismic regions was verified using measured periods of EBF buildings. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Modeling the Effect of Temperature and Precipitation on Crop Residue Potential for the North Central Region of the United States

In an effort to advance fuel security in this era of increasing fuel demand and climate change, crop residue can play an important role by serving as an alternative source of biofuel feedstock. Crop grain yield and residue production are tied to the changing climate over regional and global scale. Precipitation and temperature are among the prime climate variables that drive agricultural production across the globe. This study was carried out to understand the effect of temperature and precipitation on spatial distribution of crop residue yield potential at regional scale. Spatial autoregressive models were fitted for county level crop residue yield potential (as a major potential biomass feedstock) in the north central region of the United States using daily mean temperature and total precipitation during the crop growing season. The results of this observational study found the linear increasing trend in crop residue yield potential in most of the states across north central region of USA. Crop residue potential was also identified to have significant spatial variability. The influences of temperature and precipitation on crop residue yield potential exhibited significant interactions. Positive interaction effects were observed in states including Iowa, North Dakota, and Wisconsin. Negative interaction effects of daily mean temperature and total precipitation were observed in states including Illinois and Indiana. These results emphasize that the availability of crop residues for biofuels feedstocks will be sensitive to climatic variability and that these sensitivities will vary geographically.

Multivariate regression analysis of prime variables affecting ophthalmic patients’ satisfaction in a resource limited economy

The aim of the present study was to appraise prime dependent variables of ophthalmic patients’ satisfaction in a Nigerian public eye care facility with a view to boosting service uptake. It was a cross sectional study conducted between March and May 2012 in our centre. Consecutive clinic patients (n=251) that met study’s criteria were recruited. The patients filled interviewer-administered structured questionnaires. A total of 251 patients were analyzed comprising 139 males (55.4%) and 112 females (44.6%). Male:female ratio=1:0.8. The ages of the patients studied ranged from 17 to 92 years with a mean of 37.2 years±15.57. Bivariate analysis, validated by multiple logistic regression, showed P values of 0.021, 0.008, 0.036, 0.008 and 0.004 for privacy, comfort during eye exam, fairness (non-partiality), thoroughness of examination and expectation, respectively. Satisfaction with overall quality of services was 80.1%. The services of any eye facility should be patient-driven to attain desired goals; therefore the identified areas of patients’ dissatisfaction should be addressed for effective service uptake.

Can Macroeconomic Factors Lead Stock Returns in India?

This paper explores dynamic relation between macroeconomic variables and stock prices in India under a Vector Auto Regression framework during 2000- 2012 using monthly data. Variance Decompositions and Impulse responses have been employed to determine how long it would take for the effect of variables to work through the system. The study found money supply, interest rate and exchange rate are the prime economic variables which could make significant impact on stock return volatility. Inflation rate and Index of Industrial Production have shown very negligible influence on the stock prices. Variance Decompositions and Impulse Responses found money supply as the strongest factor influencing stock market in the long-run. When the impact of interest rate and exchange rate are found of very short term, the shocks put forth by FIIs do not cause any significant variation in the movement of nifty prices. Highly integrated structure of monetary system and its linkage with financial sector leads to the conclusion that any variable which has a negative effect on cash flows shall be in a negative relationship with the stock prices. So the monetary policy could be viewed as an effectual instrument in the hands of the government to stabilize stock market.

On pairs of quadratic equations in primes and powers of 2

In this short paper, it is proved that every pair of large positive even integers satisfying some necessary conditions can be represented in the form of a pair of quadratic equations in prime variables and k powers of 2. In particular, we have k = 584 . We also consider the similar result for cubic equations.

Metabolic profiling reveals that time related physiological changes in mammalian cell perfusion cultures are bioreactor scale independent

Metabolic profiling was used to characterize the time course of cell physiology both in laboratory- and manufacturing-scale mammalian cell perfusion cultures. Two independent experiments were performed involving three vials from the same BHK cell bank, used to inoculate three laboratory-scale bioreactors, from which four manufacturing-scale cultures were initiated. It was shown that metabolomic analysis can indeed enhance the prime variable dataset for the monitoring of perfusion cultures by providing a higher resolution view of the metabolic state. Metabolic profiles could capture physiological state shifts over the course of the perfusion cultures and indicated a metabolic “signature” of the phase transitions, which was not observable from prime variable data. Specifically, the vast majority of metabolites had lower concentrations in the middle compared to the other two phases. Notably, metabolomics provided orthogonal (to prime variables) evidence that all cultures followed this same metabolic state shift with cell age, independently of bioreactor scale.

ETA: Robust software for determination of cell specific rates from extracellular time courses

Accurate quantification of cell specific rates and their uncertainties is of critical importance for assessing metabolic phenotypes of cultured cells. We applied two different methods of regression and error analysis to estimate specific metabolic rates from time-course measurements obtained in exponentially growing cell cultures. Using simulated data sets to compute specific rates of growth, glucose uptake, and lactate excretion, we found that Gaussian error propagation from prime variables to the final calculated rates was the most accurate method for estimating parameter uncertainty. We incorporated this method into a MATLAB-based software package called Extracellular Time-Course Analysis (ETA), which automates the analysis workflow required to (i) compute cell specific metabolic rates and their uncertainties; (ii) test the goodness-of-fit of the experimental data to the regression model; and (iii) rapidly compare the results across multiple experiments. ETA was used to estimate the uptake or excretion rate of glucose, lactate, and 18 different amino acids in a B-cell model of c-Myc-driven cancer. We found that P493-6 cells with High Myc expression increased their specific uptake of glutamine, arginine, serine, lysine, and branched-chain amino acids by two- to threefold in comparison to low Myc cells, but exhibited only modest increases in glucose uptake and lactate excretion. By making the ETA software package freely available to the scientific community, we expect that it will become an important tool for rigorous estimation of specific rates required for metabolic flux analysis and other quantitative metabolic studies.

Metabolomics and Network Biology for sensitive monitoring of how growth environment changes affect the physiology of industrial-scale perfusion cultures

Metabolomic analysis can indeed enhance the prime variable dataset for the monitoring of perfusion cultures by providing a higher resolution view of the metabolic state. Metabolic profiles can capture physiological state shifts over the course of the perfusion cultures and indicate a metabolic “signature” of the phase transitions, which is not observable from prime variable data. Notably, metabolomics provides orthogonal (to prime variables) evidence that all cultures follow this same metabolic state shift with cell age, independently of bioreactor scale. Additionally, this analysis can increase the information content of process development experiments by helping better understand the impact of changes in bioreactor operating conditions on cell physiology. In this context, metabolic profiling could be integrated into the monitoring of cell physiology in perfusion cultures.

Some applications of the double large sieve

We sharpen a procedure of Cao and Zhai (J Theorie Nombres Bordeaux,11: 407–423, 1999) to estimate the sum $$\begin{aligned} \sum _{m\sim M} \sum _{n\sim N} a_m b_n \, e\left(\frac{F m^\alpha n^\beta }{M^\alpha N^\beta }\right) \end{aligned}$$ with \(|a_m|,\ |b_n| \le 1\). We apply this to give bounds for the discrepancy (mod 1) of the sequence \(\{p^c: p\le X\}\) where \(p\) is a prime variable, in the range \(\frac{130}{79}\le c \le \frac{11}{5}\). An alternative strategy is used for the range \(1.48 \le c \le \frac{130}{79}\). We use further exponential sum estimates to show that for large \(R>0\), and a small constant \(\eta >0\), the inequality $$\begin{aligned} \left| p_1^c+p_2^c+p_3^c+p_4^c+p_5^c - R\right| < R^{-\eta } \end{aligned}$$ holds for many prime tuples, provided \(2<c\le 2.041\). This improves work of Cao and Zhai (Monatsh Math, 150:173–179, 2007) and a theorem claimed by Shi and Liu (Monatsh Math, published online, 2012).

A Diophantine problem with a prime and three squares of primes

We prove that if λ 1 , λ 2 , λ 3 and λ 4 are non-zero real numbers, not all of the same sign, λ 1 / λ 2 is irrational, and ϖ is any real number then, for any ε > 0 , the inequality | λ 1 p 1 + λ 2 p 2 2 + λ 3 p 3 2 + λ 4 p 4 2 + ϖ | ⩽ ( max j p j ) − 1 / 18 + ε has infinitely many solutions in prime variables p 1 , … , p 4 .

Stress on Validity and Reliability in Selection Process: Occupational Psychologist’s Perspective Comparing with Other Features

Reliability and Validity are considered as two prime variables by the occupational psychologists. In consideration to selection process, both are reemphasized by the occupational psychologists over the years. This paper discusses the use of reliability and validity in the selection process. First, how the occupational psychologists reinforced the need of validity and reliability in selection process are discussed. Secondly, how reliability and validity can be achieved and when it is lost by examining their use from Job analysis to selection decision process. The essay also argues whether this rigor is rational in English and outside English context and also throws the light on other imperatives in comparison to Reliability and Validity by examining different labour markets. Thorndike’s (1971) model of Reliability and Selection methods Validity in different organisations and scenarios have been evaluated and the study concludes that occupational psychologists rigour in selection process is rather realistic. Other dynamics are being reasonably considered but do not have equal or greater importance.

ON PAIRS OF LINEAR EQUATIONS IN FOUR PRIME VARIABLES AND POWERS OF TWO

AbstractIn this paper, we consider the simultaneous representation of pairs of positive integers. We show that every pair of large positive even integers can be represented in the form of a pair of linear equations in four prime variables and k powers of two. Here, k=63 in general and k=31 under the generalised Riemann hypothesis.

Kloosterman sums with prime variable

Kloosterman sums with prime variable

The Role of Individual Differences in Promoting Front Liners to Become Customer-Oriented: A Case of the Hotel Industry in Malaysia

As other service industry, hoteliers are highly relying on their contact employees known as front liners to deliver services to customers. Therefore, the behaviors of front liners can influence customers' perceptions of a hotel service. Customer-orientation behavior of employees has become a prime variable of interest for organizations wishing to successfully market their products. However, previous researches on this area have stressed the need for a better understanding of the process relating to customer orientation behavior and its influencing factors. This paper investigates the influence of organizational commitment, self-efficacy and intrinsic job motivation of front liners on customer-orientation behavior.