bluuebunny/crossref_metadata_2025 huggingface dataset:
Earnings Surprises, Asymmetry of Returns, and Market-Level Changes: An Industry Study
Authors: Ho Yew-Kee , Sequeira John M.
Published: July 2017

Recent studies that examine the relationship between stock returns and unexpected earnings may be broadly categorized into two main approaches: the firm-specific approach of Skinner and Sloan (2002) and Lopez and Rees (2001), and the market-wide regime shifting behavior of Conrad, Cornell, and Landsman (2002). Although both approaches provide possible explanations for the asymmetric behavior of earnings shocks, no known study has attempted to establish which approach has stronger empirical support. In this paper, using industry sector results, we generally find stronger empirical support for the firm-specific approach as being more representative of stock price behavior.
A Preliminary Test of the Presence of Window Dressing: Evidence from Institutional Stock Trading
Authors: Bildersee John , Kahn Nathan
Published: July 2017

For years, investors and accountants have speculated that managers “window dress,” that is, undertake actions to improve their balance sheets before they issue their financial reports. Similarly, institutional money managers are said to adjust their stock portfolios before the release of their quarterly reports.

In this paper, stock market volume data for the overall market and for a number of different sample portfolios are examined to see if there is abnormal end-of-period trading activity. The results suggest that trading activity increases at the end of each quarter. This result is consistent with the window dressing hypothesis.
Determinants of Accounting Change: An Industry Analysis of Depreciation Change
Authors: Dharan Bala G. , Mascarenhas Briance
Published: July 2017

This study examines whether the large number of depreciation-related accounting changes made by oil and gas drilling firms during the early eighties can be explained by changes in earnings prospects and related changes in agency cost variables. Empirical evidence, based on all thirty contract drilling firms for which data were available, shows that a model consisting of variables representing changes in sales, rig utilization rate and income before accounting change has significant explanatory and predictive power. Compared to a model consisting only of changes in sales, leverage or dividend constraint, models containing income change and rig usage change have better identification and prediction performance. The results imply that the dramatic declines in rig utilization during the early eighties, combined with related changes in income, led to the observed accounting changes in this industry.
The Pratt-Arrow Requirement in a Fourth Degree Polynomial Utility Function
Authors: Benishay Haskel
Published: July 2017

The main objective of this paper is to show that a fourth degree polynomial utility function proposed in a recent paper, which meets the requirement of risk aversion, can be restricted further to meet the added requirement of decreasing absolute risk aversion. Secondary objectives are to show the features and advantages of the proposed function.
Intra-Industry Market Reactions to Failures of Publicly Held Savings and Loans
Authors: Blacconiere Walter G. , Bowen Robert M.
Published: July 2017

This study examines the consequences of failures involving publicly held S&Ls on the market value of surviving firms in the industry. Market reactions of surviving firms are predicted to be associated with the circumstances surrounding the failure as well as the characteristics of the surviving S&Ls. Four competing (but not mutually exclusive) hypotheses are examined.

An overall positive intra-industry market reaction was observed for the failures of eight publicly traded S&Ls during 1985 and 1986; however, this reaction was not significant at conventional levels. Cross-sectional analyses of the relation between market reactions and characteristics of failed and surviving S&Ls provides some support for the hypothesis that positive reactions were associated with a perceived reduction in competition, especially for stronger surviving S&Ls. The three remaining hypotheses (related to regulatory enforcement, regulatory resources, and the contagious effects of individual failures) receive only weak support.
Estimating the Permanent Component of Accounting Earnings Using the Unobservable Components Model: Implications for Price-Earnings Research
Authors: Ramesh K. , Thiagarajan S. Ramu
Published: July 2017

This study proposes the unobservable components (UC) model as a conceptually and statistically superior approach to modeling the stochastic properties of accounting earnings. Based on the UC model, accounting earnings are decomposed into permanent and transitory components and the earnings-return relation using these components is reexamined. Once the transitory component is eliminated from accounting earnings, the average firm-specific earnings response coefficient (ERC) estimates from regressing annual returns on earnings changes increase more than 300 percent—from 2.192 to 7.770. Using a 10-year returns model, the study documents that the stock prices in the long run predominantly reflect the permanent component of earnings. Results also suggest that the success of aggregate earnings in explaining long-window returns is due to the aggregate earnings proxying for the permanent component of earnings. Finally, the study provides evidence suggesting that no simple income statement classification scheme can effectively isolate the transitory component of earnings.
A Test of Audit Pricing in the Small-Client Segment: A Comment
Authors: Gist Willie E.
Published: July 2017

This study is the second to provide a richer test of the association between auditor size and audit fees by using three audit firm size classes in the small-client segment of the U.S. audit market. The finding of a Big 8 (now Big 6) price premium is consistent with Francis and Simon [1]. However, this price premium exists only with respect to local/regional firms. Francis und Simon showed that the Big 8 price premium exists with respect to both second-tier and local/regional firms. The present study also provides evidence of a second-tier price premium over local/regional firms. The results imply product differentiation to both Big 8 and second-tier firms. Plausible reasons for differences in results between the two studies are given.
Dispersion in Industry Price Changes and the Relative Association between Alternative Income Measures and Security Returns
Authors: Linsmeier Thomas J. , Lobo Gerald J. , Kanaan George K.
Published: July 2017

The objective of this research is to assess whether the incremental information content of current cost (CC) income and constant dollar (CD) income is time-period specific. Based on work by Lim and Sunder (1990), we predict that CC (CD) income is more likely to exhibit incremental information content over CD (CC) income when the dispersion in annual price changes across industries is large (small). Evidence provided using FASB Statement No. 33 data is consistent with these predictions. That is, CD (CC) income is shown to exhibit incremental information content over CC (CD) income in the years 1980 and 1983 (1981 and 1982). We then extend this analysis to a disclosure environment that includes historical cost (HC) income, and find that CD (CC) income also has incremental information content over HC income in those same years—1980 and 1983 (1981 and 1982). Thus, by identifying time periods when either CC income or CD income is the preferred income measure, we also are able to provide sample-wide evidence that accounting data adjusted for changing prices of productive assets provide incremental information over HC income.
Earnings Response Coefficient and Persistence: New Evidence Using Tobin's q as a Proxy for Persistence
Authors: Harikumar T. , Harter Charles I.
Published: July 2017

Prior studies have documented that the earnings response coefficient is positively related to persistence and growth and negatively related to beta and the risk-free rate. Although these studies provide interesting tests of economic theories, they do not provide a current measure of persistence. A current measure of persistence is useful for investors to assess the information content in current earnings innovations. We provide evidence that indicates a statistically significant positive relation between the earnings response coefficient and Tobin's q, thus suggesting that a firm's q ratio is a current proxy for persistence.
The Relation of Inherent and Control Risks to Audit Adjustments
Authors: Wallace Wanda A. , Kreutzfeldt Richard W.
Published: July 2017

Auditors perceive that their evaluations of clients' inherent risks and internal controls are useful in assessing the likelihood of errors. Past research has indicated descriptive power for inherent risk variables but has failed, to date, to demonstrate a systematic relation between internal controls and error rate. This study extends earlier work by using a field study to measure client attributes tied to inherent and control risks and then evaluates the effectiveness of these attributes in explaining variations in adjustment rates among 260 audit clients.

The data base has 1,506 adjustments, which are analyzed using a judgmentally selected regression model and a cost-beneficial analogy to an “all possible regressions” approach. Multiple variable relations provide statistically significant descriptive power with respect to audit adjustments.

The results suggest the plausibility of developing a model for use in audit planning that formulates a prediction of error rate based on client inherent risk and internal control attributes.
Improving the FASB's Requirements for Off-Balance-Sheet Market Risk Disclosures
Authors: Palmer Richard J. , Schwarz Thomas V.
Published: July 2017

This paper discusses the requirements and limitations associated with SFAS No. 105 market risk disclosures, empirically examines the current implementation of SFAS No. 105 in the financial disclosures of financial institutions, and proposes improvements to the market risk disclosures presently required by the FASB. The results of the empirical analysis of 35 large U.S. financial institutions show that (1) many firms indicated a concern that statement users are not able to clearly distinguish between required contract dollar amount disclosures and actual risks; (2) although most firms use instruments with OBS risk for proprietary hedging and trading, no firm provides a useful detailed breakdown of the degree of risk attributable to these different activities; (3) the greatest conformity in reporting occurs in those firms with the largest contract dollar volume (in absolute terms and as a percent of equity); and (4) very few firms take any initiative in the reporting of additional disclosures.

In light of these findings, this paper proposes a new method of market risk disclosure that is based on the margin required by exchanges and their Clearing Corporations. Margin disclosure is shown to be superior to SFAS No. 105 requirements in that it (1) directly correlates with the true risk of a firm's position, (2) is based on the entire financial position of a firm, (3) is easily obtained for even the most complex financial positions, (4) is dynamic in response to changing market conditions, (5) is determined by an independent third party whose main interest is the measurement of market risk, and (6) is a numeric rather than descriptive measure.
Financial Analyst Assessment of Company Earnings Quality
Authors: Bricker Robert , Previts Gary , Robinson Thomas , Young Stephen
Published: July 2017

This study investigates sell-side financial analysts' interpretations of the phrase “earnings quality” and their preference for accounting methods. The data are a sample consisting of 479 sell-side financial analyst full-text reports for a set of companies stratified on exchange, SIC code, and size in three recent time periods. These reports illustrate the importance placed by analysts on identifying companies' core earnings. The results show that analysts associate high earnings quality with near-term earnings predictability. This predictability is defined in an economic sense in terms of a low level of earnings volatility, and in an accounting sense in terms of management discretion over the establishment and adjustment of certain conservative reserves, allowances, and off-balance-sheet assets. Limited association was found between earnings quality and the application of conservative accounting methods, per se.
Managerial Entrenchment, Reputation and Corporate Investment Myopia
Authors: Nagarajan Nandu J. , Sivaramakrishnan K. , Sridhar Sri S.
Published: July 2017

In this paper, we demonstrate that informational asymmetries within a firm along with managerial labor market concerns can jointly result in investment myopia being equilibrium behavior. In contrast to earlier studies (like that of Shleifer and Vishny [1989]), we find that in the presence of both reputation and entrenchment incentives, managers invest in long-term projects for reputation building and short-term projects to entrench themselves. Further, we establish conditions under which delegating project selection is optimal, even though it requires that the owner tolerate short-term project selection. Finally, we present several empirical implications of our analysis.
Accounting Measures of Business Performance and Tobin's q Theory
Authors: Chen Kevin C.W. , Lee C.W. Jevons
Published: July 2017

In this paper, Tobin's q theory is applied to evaluate the informativeness of the traditional accounting measures of business performance and the measures derived from the cash recovery rate (CRR). The informativeness is defined in terms of the correlation of the performance measure and the internal rate of return implied in a ratio known as Tobin's q. The paper shows that the traditional ROI does weakly reflect the underlying profitability. The internal rate of return derived from the cash recovery rate approach, however, seems to be more informative than the ROI.
Auditors' Judgment Performance under Stress: A Test of the Predicted Relationship by Three Theoretical Models
Authors: Choo Freddie
Published: July 2017

Three competing theories of stress and judgment performance, namely, working memory capacity theory (Eysenck [1979]), cue utilization theory (Easterbrook [1959]), and coping behavior theory (Folkman [1984]) were compared for their efficacy in explaining the form of stress-induced performance changes in auditors' judgment. Two studies were conducted to test the goodness of fit of the three predicted stress-judgment relationships.

The first study was a five-phase field research that included the development of an Audit Mental Stress Scale and the usage of a complex audit judgment case. The results indicated that the cue utilization theory had a higher explanatory power than the other two competing theories. In accordance with this theory, auditors' judgment performance improved as stress increased from a low to moderate level with optimal performance efficiency occurring at a moderate level of stress, and thereafter a decrement in judgment performance at an excessive level of stress. In other words, there was an inverted U-shaped relationship between stress and judgment performance.

The second study reinforced the findings with a laboratory experiment. Forty-eight auditors were randomly assigned to four groups of 12 subjects each and the four groups assigned to one of four time pressure conditions. The auditors performed the same audit judgment case as in study one. An ANOVA that used orthogonal polynomial coefficients to test for the presence of trend was applied to identify which of the three models best fit the data. The results indicated that an inverted U-shaped curve contributed most to the data trend. The goodness of fit test once again supported the predicted relationship in Easterbrook's cue utilization theory.
The Market Impact of Early Debt Redemptions: Evidence from the Consideration of Accounting Gains and Losses
Authors: Haw In-Mu , Jung Kooyul , Kim Tae-Yong , Pastena Victor , Furnas Clifford C.
Published: July 2017

The study examines the relationship between accounting gains and losses resulting from early debt redemptions (EDRs) and abnormal returns at the initial announcement of the EDRs. We explore alternative explanations that were omitted from prior literature and test for both income-based and leverage-based explanations for the market's reaction to the EDRs. We find a positive association between the EDR income effect and abnormal returns, and negative relation with both the pre-EDR debt-equity ratio and leverage reduction resulting from the EDRs. We discriminate between alternative explanations using interaction effects between the EDR income and leverage variables. Although the overall results are consistent with the information signaling hypothesis, they also provide mixed support for the contracting hypothesis. Additional evidence indicates that the signaling effect of the EDRs is stronger for smaller firms and EDRs subject to taxes.
An Investigation into the Firm Size Effect: A Security Market Plane Approach
Authors: Hsia Chi-Cheng , Fuller Beverly R.
Published: July 2017

This paper tests the firm size effect with two different approaches. First, the “messy” and “clean” methods of Fama and French are used; the firm size effect is found to remain but only after the regression residuals are analyzed. Then a security market plane and a proxy of it are defined and the proxy security market plane is used for testing. The results indicate that the firm size effect is reliably detected and statistically “explained” by a proxy security market plane for the sample period from July 1963 to June 1986.
Does the Ownership Structure of Debt and Equity Affect the Agency Costs of Debt? Japanese Evidence
Authors: Hwang LeeSeok , Kim Yong O.
Published: July 2017

This paper examines the effect of the ownership structure (of debt and equity) on the agency problems of debt. This issue is particularly relevant for Japanese keiretsu firms. Member firms in a keiretsu are linked through business ties and reciprocal shareholdings. A central figure of the keiretsu is the main bank that serves as a corporate monitor. We hypothesize that the main bank's monitoring intensity varies with the degree of its keiretsu member banks' financial interests in the member firms. We first find that the leverage of keiretsu firms in our sample is significantly negatively related to proxies for the source of potential agency conflicts (e.g., R&D expenditures and intangible assets), implying that Japanese keiretsu firms also suffer from agency problems of debt. This is contrary to the popularly held view that Japanese firms are free of agency problems of debt since banks are often both large creditors and shareholders. We then consider the ownership structures based on debt and equity holdings by member banks and member firms within the same keiretsu. Consistent with our hypothesis, our empirical results show that agency costs of debt are pronounced among firms in which the members have low-debt and low-equity holdings, but are mitigated substantially for other firms in which the members have significant holdings of debt and/or equity, in the order of low debt and high equity, high debt and low equity, high debt and high equity.
The Materiality of Care and Nurses’ “Attitude Problem”
Authors: Tantchou Josiane Carine
Published: July 2017

Health systems in Africa have been widely studied in the social sciences. Several aspects have been addressed in particular: the provision of and access to care, working conditions, the human resources crisis, and patient–provider relations, for example. In this respect, the idea of an “attitude problem,” with health-care providers offering different services for different patients, has been suggested. Recently, researchers have studied the impact of global health initiatives on local health systems, mainly in the fight against HIV/AIDS. Others have explored why some health issues have attracted more attention than others. Despite this wealth of studies, one point remains insufficiently addressed: the materiality of care and its impact on interactions (human and nonhuman) within hospital settings. In this article, I consider the heuristic value of the uses of a maternity ward in a resource-limited country (Cameroon) to understand health workers’ so-called attitude problem, specifically, the tension characteristic of patient–provider interactions. I suggest that this tension is related to a continuous process of translation and anticipation to adapt the maternity ward’s space to everyday activities. Drawing on Akrich’s description of technical objects, and Lussault’s pragmatics of space, I attempt to show that in this context, care is also an art of tinkering with unpredictable bodies in unstable hospitals’ spaces.
Explaining sexual minorities’ disclosure: The role of trust embedded in organizational practices
Authors: Capell Ben , Tzafrir Shay S. , Enosh Guy , Dolan Simon L.
Published: July 2017

This paper reports on an empirical study that demonstrated how organizational inclusion practices and employees’ trust in their organization and supervisors affect their willingness to share personal information that could potentially lead to workplace discrimination. The findings are based on data obtained from 431 sexual- and gender-minority employees using an anonymous online survey. The results reveal that trust in the organization and the supervisor fully mediates the relationship between organizational policies and practices and workplace disclosure. In other words, in organizations where policies and practices generate trust, employees are more willing to disclose their minority identity. Our analysis also reveals how trust in the organization and the supervisor interacts with psychological variables associated with the workplace disclosure decision.
Individual Approach to the Shadow Economy
Authors: Tolla Marco
Published: July 2017

This article analyzes the relationship between the shadow economy and tax evasion in order to verify if their dynamics are substantially identical or may present elements of differentiation, even though the two aforementioned phenomena appear (on the basis of certain statistical definitions) to overlap in terms of economic values. To this end, the article proceeds by providing a series of terminological definitions that are useful to properly classify these phenomena and then it lists the main methodologies used for their quantification. Although such methods and their strengths and weaknesses are well known in economic studies, it is useful to recall them in order to underline some questions connected with the development of a model aimed at describing the approach to the shadow economy and tax evasion from a microeconomic perspective. The first question is if the underground economy can exist in absence of tax evasion and, in that case, which are the factors that allow it. A related question is how is it possible from a microeconomic perspective to estimate in percentage the overall disadvantage (fiscal and non-fiscal) deriving from the total declaration of economic activities to public authorities compared to firms that work in the underground economy? On this matter, reference to case law and regulatory measures, performed in order to create an economic-juridical parallel on the shadow economy and tax evasion, has been made with regard to the Italian legal system, so as to fit the mathematical model as much as possible to observed facts.

JEL: K42, H26, O17
Mindfulness in the middle school classroom
Authors: Doss Kristy Kowalske , Bloom Lisa
Published: July 2017

Instructors of a middle school gifted language arts class implemented a 30-day unit of study on mindfulness in order to help students learn techniques to alleviate stress, perfectionistic tendencies, and anxiety. Practicing mindfulness techniques, such as meditation, provides individuals with tools to understand the mind and body and encourages individuals to not dwell on past events or fixate on future events, appreciating the here and now and living in the moment. Some gifted students struggle with social and emotional issues such as perfectionism and anxiety, and these conditions can create a cycle of stress rooted in nervousness, agitation, and compulsive thoughts. Instructors explained the components of mindfulness, provided daily guided meditations, and encouraged students to apply the techniques in their everyday lives. Results varied for each student with some able to use the mindfulness exercises to combat problems, while others struggled with understanding the purpose or potential benefits of mindfulness.
Emotional Content in Wikipedia Articles on Negative Man-Made and Nature-Made Events
Authors: Greving Hannah , Oeberst Aileen , Kimmerle Joachim , Cress Ulrike
Published: July 2017

Wikipedia emphasizes the objectivity of content. Yet, Wikipedia articles also deal with negative events that potentially elicit intense emotions. Undesirable outcomes (e.g., earthquakes) are known to elicit sadness, while undesirable outcomes caused by others’ actions (e.g., terrorist attacks) are known to elicit anger. Internet users’ emotional responses are likely to end up in Wikipedia articles on those events as characteristics of Internet users spill over to Wikipedia articles. Therefore, we expected that Wikipedia articles on terrorist attacks contain more anger-related and less sadness-related content than articles on earthquakes. We analyzed newly created Wikipedia articles about the two events (Study 1) as well as more current versions of those Wikipedia articles after the events had already happened (Study 2). The results supported our expectations. Surprisingly, Wikipedia articles on those two events contained more emotional content than related Wikipedia talk pages (Study 3). We discuss the implications for Wikipedia and future research.
Equilibrium, kinetics and thermodynamic adsorption studies of acid dyes on adsorbent developed from kenaf core fiber
Authors: Idan Intidhar J , Abdullah Luqman C , Choong Thomas SY , Jamil Siti Nurul Ain B Md
Published: July 2017

Quaternized kenaf core fiber (QKCF) was used as an adsorbent for adsorption of anionic Acid Blue-25 (AB) and anionic Acid Green-25 (AG) dyes. Chemical treatment with (3-chloro-2-hydroxypropyl) trimethylammonium chloride under basic condition was applied in order to alter the surface properties of the raw kenaf core fiber. Adsorption studies were carried out to delineate the effect of initial dye concentration, temperature and pH on removal of dyes. The results show that the percentage removal of Acid Blue-25 and Acid Green-25 dyes were increased by increasing the concentrations of dyes. In addition, the maximum percentage removal was 99.8% and 99.65% for Acid Blue-25 and Acid Green-25, respectively. Langmuir, Freundlich and Temkin isotherm models were applied to analyze the data for dye adsorption at 15℃, 25℃, 35℃, and 45℃. The experimental data were best represented by the Langmuir model with maximum adsorption capacity of 303.03 mg/g and 344.83 mg/g for Acid Blue-25 and Acid Green-25 dyes, respectively, at 15℃, and the kinetic data for both dyes were best represented by the pseudo-second-order kinetic model. Thermodynamic studies indicated that the reactions of Acid Blue-25 and Acid Green-25 dyes were endothermic. It was concluded that QKCF adsorbent can be utilized as an efficient low-cost adsorbent for removal of anionic dyes.
Effect of Framework Charge Density on the Ion Exchange Properties of Zeolites
Authors: Townsend R. P. , Franklin K. R. , O'Connor J. F.
Published: July 2017

Members of a group of zeolites such as X and Y differ from each other only in the degree to which aluminium has isomorphously replaced silicon within the framework. As far as ion exchange properties are concerned, the effects of isomorphously increasing the number of aluminiums per unit cell are fourfold: (a) the unit cell volume increases; (b) the framework charge density increases; (c) there is a decrease in the ratio of the number of available crystallographic cationic sites to the number of framework charges on the lattice; (d) the zeolite becomes more hydrophilic. The effects of changing isomorphously the framework charge on the degree of hydrolysis, stability, and selectivity of the zeolite are discussed. The problems of attempting to correlate changes in selectivity with bulk properties of zeolites is first considered and then experimental data on hydronium exchange, the sodium/ammonium exchange in faujasites and lead exchanges in faujasites are presented. With respect to the latter, the limitations of dielectric theory are emphasized.
Characteristic Equilibrium Curves of Gas Adsorption
Authors: Costa E. , Calleja G. , Cabra L.
Published: July 2017

With the theoretical basis stated by Myers & Sircar for formulating a new characteristic equilibrium curve of adsorption on heterogeneous adsorbents, three characteristic curves of adsorption on 5A and 13X zeolites and AC–40 activated carbon have been obtained, showing a correct fit of equilibrium data of different adsorbates at various temperatures. These characteristic curves are useful for the prediction and extrapolation of adsorption isotherms on the same absorbents.
Adsorption of Aromatics on Silica Gel
Authors: Roethe K. -P. , Gutsche R. , Richter W. , Roethe A. , Caro J. , Kärger J.
Published: July 2017

Breakthrough curves of naphthalene from n-alkane solution with specific feeds typical of liquid phase processes in packed beds of silica gel which contains pores larger than the critical diameter of the naphthalene molecule are investigated. With measurements under conditions of the linear region of the adsorption isotherm it is found that the observed mass-transport is mainly determined by the mixing process in the flowing bulk phase and by mass transfer through the boundary layer at the interface between the liquid bulk phase and the adsorbent grain. In comparison with these mechanisms, the influence of molecular transport processes in the pore system of the silica gel grain is negligibly small. This information is shown to be available by a direct observation of the elementary steps of molecular transport applying the n.m.r. pulsed field gradient technique.
Surface Behaviour of β-FeOOH: Point of Zero Change and Interactions with Anions and Cations
Authors: Parida K. M.
Published: July 2017

The acid-base dissociation behaviour of the surface of β-FeOOH in aqueous suspension has been investigated by potentiometric titration. The zero point of charge of the electrical double layer of the oxide/solution interface (pH = 7·6 ± 0·1 in KNO3, NaNO3 and LiNO3 electrolytes) coincides with the pH of the isoelectric point, determined by the solid addition method. Chloride and sulphate anions are strongly adsorbed on the β-FeOOH surface and thus modify the balance of positive and negative groups on the surface. The sequence of interaction of monovalent cations with the surface is K+ = ≤ Na+ ≤ Li+. β-FeOOH appears to behave essentially in the same manner as found previously for α-FeOOH.
Relation Between the Preparation and the Morphology of Silica-Alumina Gels
Authors: González-Velasco J.R. , González-Marcos J.A. , Gutiérrez-Ortiz M.A. , Romero A.
Published: July 2017

The effect of the variables involved in the preparation of silica-alumina gels on their morphology has been analysed by experimental design techniques. Relationships between the surface area and pore volume of the gels and the variables with the greatest influence, namely precipitation rate and temperature, impregnation concentration and calcination temperature have been obtained.
Adsorption Parameters and Superficial Species in the Nickel-Alumina System
Authors: Rodriguez Raúl A.E. , Caceres Carmen V. , Blanco Blanco , Tomas Horacio J.
Published: July 2017

The equilibrium adsorption of nickel on γ-alumina was studied at 293 and 333 K. Nickel nitrate solutions in the range 0.1 - 2% (w/v, expressed as NiO) were used. Both the equilibrium constant and the number of adsorption sites increased with the adsorption temperature. Adsorption and desorption rate constants were estimated by fitting a theoretical model to the profiles obtained by impregnation of γ-alumina thin layers with nickel nitrate solutions.

Representative solid samples differing in nickel contents were studied along both isotherms by X-ray diffraction, diffuse reflectance and X-ray photoelectron spectroscopy. It is concluded that, in the composition range studied, nickel forms a partially inverted spinel (NiAl2O4); the degree of inversion being greater in the samples prepared at 293 K than in those corresponding to 333 K. Also, the dispersion of nickel species is constant for each adsorption temperature.
Heats of Adsorption and Reaction of CO on Iron/Manganese Oxide Catalysts
Authors: Möller P. , Papp H.
Published: July 2017

The heats of adsorption and reaction of CO have been measured on reduced Fe/Mn oxide catalysts of different compositions at temperatures between 263 and 543 K. The heats of adsorption depend only to a small extent on the manganese content of the catalyst and are independent of the temperature of reduction. The former fact points to a more structural than electronic effect of the manganese oxide addition. The heats of adsorption are, however, strongly dependent on measurement temperature, increasing from about 60 kJ mol-1 at 263 K to about 200 kJ mol-1 at 493 K and then decreasing again to about 180 kJ mol-1 at 543 K. This temperature dependence can be explained by consecutive reactions following CO adsorption, i.e. the Boudouard reaction, dissociation of CO and diffusion of carbon into the bulk of iron. The amount of CO adsorbed is correlated to the metallic iron content in the surfaces of the catalysts.
Adsorption of Acid on Charcoal: The pH-pKa Relationship at the Adsorption Maximum
Authors: Helmy A.K. , Ferreiro E.A. , Bussetti S.G. De
Published: July 2017

The adsorption of quinoline and/or 8-hydroxyquinoline on charcoal was studied as a function of pH and concentration for the purpose of investigating the relationship between the pH at the adsorption maximum and the pKa, of the organic acid cation. Equations based on the theory of Langmuir were derived and tested experimentally. The pH/pKa, ratio was found to depend on the constants of the adsorption reaction as well as on the ratio of cation to neutral molecules on the surface at the adsorption maximum. Individual isotherms were calculated for the cation and for the neutral molecules. These were of type III for the cation and type I for the neutral molecules, thus indicating that adsorbate/adsorbate interactions are greater than adsorbate/adsorbent interactions for the cation molecules.
Apparent and Partial Specific Sorption of Phosphate by Binary Mixtures of Hydrated Al Oxides
Authors: Helmy A.K. , Ferreiro E.A. , de Bussetti S.G.
Published: July 2017

Phosphate sorption by binary mixtures of bayerite and amorphous Al oxide has been studied at pH values of 6, 7 and 8.5 as a function of phosphate concentration and mixture composition. By application of the thermodynamic method of partial quantities, the apparent and partial specific sorption of phosphate by each component in the mixture has been calculated. It was found that sorption increased as the proportion of oxide increased in the mixtures, while the apparent and partial quantities of the oxide increased as the amount of oxide decreased at constant bayerite, pH and phosphate concentration.
Pore Diffusion Model for the Adsorption of Basic Dyestuffs onto Natural Clay in Batch Adsorbers
Authors: El-Geundi Mohammad S.
Published: July 2017

The adsorption of basic dyestuffs (Basic Blue 69 and Basic Red 22) onto natural clay has been studied using a series of batch adsorption runs. The pore diffusion model (PDM) has been developed based on external mass transfer and pore diffusion to predict the performance of a batch adsorber. A computer program has been developed to generate theoretical Sherwood number-time curves and these results were adjusted to experimental Sherwood number-time curves by means of a ‘best fit’ approach. The variables of initial dye concentration and natural clay mass have been successfully correlated using a single external mass-transfer coefficient, Ks, and a single effective pore diffusion coefficient, Deff. The Ks values are 3.3 × 10−5 and 2.6 × 10−5 m/s for Basic Blue 69 and Basic Red 22, respectively. The Deff values are 7.3 × 10−10 and 9.6 × 10−10 m2/s for Basic Blue 69 and Basic Red 22, respectively.
High-Pressure Methane Adsorption on NaX and NaY Zeolites with Different Si/Al Ratios
Authors: Mentasty L. , Woestyn A.M. , Basaldella E. , Kikot A. , Zgrablich G.
Published: July 2017

One method of increasing the storage capacity of compressed natural gas, an alternative for vehicular fuel, is by adsorbing it on to microporous solids such as zeolites or activated carbons. NaX and NaY zeolites with different Si/Al ratios have been synthesized and characterized. Experimental adsorption isotherms for CH4 on these zeolites have been obtained at different temperatures over a pressure range of 0–5 MPa using a high-pressure volumetric apparatus. Isosteric heats of adsorption have been estimated and the isotherms analyzed applying a statistical thermodynamic model. The efficiency of this solid as a methane storage system has been evaluated and compared with other sorbents. Encouraging results have been obtained.
Influence of Surface Roughness Variation on the Surface-Enhanced Raman Scattering (SERS) Signal
Authors: Kruszewski S.
Published: July 2017

The roughness of a silver electrode was changed by varying the parameters employed in the oxidation–reduction procedure. Investigations of the surface-enhanced Raman scattering (SERS) intensity as a function of parameters of the oxidation–reduction cycle (ORC) procedure and the extent of roughness have been performed. On the basis of these investigations, it is possible to conclude that deep pores on the surface have a greater influence on the SERS signal than the grain size.
Adsorption Properties of Activated Carbons Obtained from Polymer Wastes
Authors: Youssef A.M. , Alaya M.N. , Nawar N.
Published: July 2017

Non-activated carbon has been prepared by carbonizing waste products manufactured from phenol formaldehyde at 1073 K in a nitrogen atmosphere. Activated carbons were obtained by gasifying the non-activated product with air at 673 K, or with steam at 1173 K, to different levels of burn-off. The adsorption of nitrogen at 77 K and of carbon dioxide at 298 K was measured for all the carbons prepared using volumetric apparatus. The adsorption of iso-octane and α-pinene at 320 K was carried out gravimetrically using silica spring balances. The adsorption of methylene blue and of phenol from their aqueous solutions was determined spectrophotometrically. The adsorption of ammonia from its aqueous solution at 308 K was determined colorimetrically.

The surface area of the activated carbons increased with increasing percentage burn-off to reach a maximum and then decreased with further increase in percentage burn-off. Gasification with oxidizing gases changed the porosity of the carbon with the change depending on the extent of gasification. The adsorption of iso-octane and α-pinene increased with increasing percentage burn-off as a result of pore widening. The low burn-off carbons obtained from phenol formaldehyde wastes are characterized by extremely high surface areas and microporosity, and a high CO/CO2 ratio on outgassing. The carbons exhibit high phenol adsorption capacities. Ammonia adsorption is favoured on carbons of a low CO/CO2 ratio.
A Simple Method of Adsorbent Washing
Authors: Lodyga B. , Narowski R. , Lodyga A. , Leboda R.
Published: July 2017

A method and a design of an apparatus for continuous washing, under dynamic conditions, of products of surface reactions carried out on adsorbents with a highly developed surface are presented. The advantages of the method are illustrated by examples of the removal of surface mineral contaminations from active carbons (specific surface area ∼1150 m2/g) with hydrochloric acid. Application of the dynamic method reduced by several times the amount of water necessary to wash away HCl and mineral contaminations from the adsorbent surface and also substantially reduced the time necessary for the purification of a porous surface in comparison to the traditional static method.
Changes in the Adsorption Properties of Activated Carbon due to Partial Oxidation of the Surface
Authors: Youssef A.M. , El-Khouly A.A. , Ahmed A.I. , El-Shafey E.I.
Published: July 2017

The textural properties (surface area and porosity) of activated carbons change upon treatment with oxidizing solutions. The extent of this change is related to the strength of the oxidizing agent. Oxidation also changes the chemistry of the surface by forming carbon–oxygen groups which are the sites upon which the initial adsorption of water vapour takes place. The adsorption of water vapour at 300–320 K is mainly physical and the isosteric heat of adsorption decreases continuously as the surface coverage increases. The entropy of adsorption of water vapour on untreated and oxidized carbons, at different adsorption temperatures, has been calculated.
Some Peculiarities of Silica Modification Under High Reagent Pressure. I. Methodological Aspects
Authors: Sidorchuk V.V. , Tertykh V.A. , Leboda R. , Hubicki Z.
Published: July 2017

The effect of the following factors on the chemical and geometrical modification of aerosilogel (prepared from aerosil) was studied: the physicochemical characteristics of the modifying reagent pressures, the preparation conditions for the silica surface, the reaction temperature, the reagent pressures, the duration of treatment and the method employed for the modification process. The course of the surface reaction was followed by IR spectroscopy, differential thermal analysis and adsorption. During high-pressure modification, the geometrical parameters of the porous silica structure may be changed.
Variation of the Hydrodynamic Polymer Layer Thickness on Solid Surfaces with Molecular Weight and Concentration
Authors: Millot S. , Loubet J.L. , Georges J.M.
Published: July 2017

An extensive study on the determination of the 'hydrodynamic' layer thickness of polymer solutions and melt polymers was conducted with a surface force apparatus. For different concentrations and polymer molecular weights, a 'hydrodynamic layer' of fluid was detected on each solid surface which did not contribute to the flow. These thicknesses, denoted as LH, are compared to the characteristic polymer dimensions and the hydrodynamic (RH) and gyration (Rg) radii. It appears that in contrast to the molecular weight, polymer concentration has little effect on the relative hydrodynamic layer thickness (LH/2RH, LH/2Rg). Indeed, this ratio indicates that two coils of low molecular weight and one coil of high molecular weight are 'immobile' on the solid surfaces. The mechanism responsible could be entanglement of the free (unattached) chains in the bulk with immobilized chains on the surface.
Porous Structure and Adsorption Properties of Synthetic Active Carbons
Authors: Puziy A.M. , Leboda R. , Bogillo V.I. , Shkilev V.P. , Lodyga A.
Published: July 2017

The porous structures of synthetic active carbons have been examined in detail on the basis of nitrogen adsorption isotherms at 77 K using the αS method, the Dubinin–Stoeckli approach and the regularization technique. Analysis of the porosity of synthetic active carbons shows that carbons obtained under identical conditions have dissimilar adsorption properties depending on the size of the granule. The application of the Dubinin–Stoeckli equation for the characterization of strongly heterogeneous carbons overestimates the maximum amount adsorbed in the micropores. In contrast to the Dubinin–Stoeckli equation, the regularization method gives a two-peak micropore size distribution and enables adsorbents with a bimodal porous structure to be estimated.
Recycling of Industrial Solid Wastes: 'Waste' FeIII/CrIII Hydroxide as an Adsorbent for the Removal of Toxic Ions and Dyes from Wastewater
Authors: Namasivayam C. , Senthilkumar S.
Published: July 2017

'Waste' FeIII/CrIII hydroxide, generated from the treatment of CrVI in fertiliser industry effluent, was used as an adsorbent for the removal of toxic ions such as AsIII, HgII, CrIII and PO43–, and dyes such as Rhodamine-B and Procion Orange M2R, from aqueous solutions. The removal was efficient except for Procion Orange.
Thermodynamic Verification of the Theory of Volume Filling of Micropores for Adsorption on Activated Carbons
Authors: Rychlicki G. , Terzyk A.P.
Published: July 2017

The thermodynamic verification of the potential theory of adsorption for the adsorption of methanol, ethanol, carbon dichloride and carbon tetrachloride on polyfurfuryl microporous carbons is presented. Using the results of adsorption isotherm measurements at different temperatures, the condition for temperature independence of a so-called ‘characteristic’ curve was checked. It is shown that this assumption is not fulfilled for four out of eight of the cases investigated. For the systems that obey this postulate, the typical minimalization procedure for the numerical calculation of the potential theory parameters (using DR, DA and DI models), usually used by other authors, was applied. Finally the adsorption enthalpy values predicted by the potential theory of adsorption equations were calculated and compared with those measured calorimetrically.
Exploring Cloud Computing Tools to Enhance Team-Based Problem Solving for Challenging Behavior
Authors: Johnson LeAnne D.
Published: July 2017

Data-driven decision making is central to improving success of children. Actualizing the use of data is challenging when addressing the social, emotional, and behavioral needs of children across different types of early childhood programs (i.e., early childhood special education, early childhood family education, Head Start, and childcare). Exploring tools that are available through cloud computing, within systems that are being increasingly adopted by education agencies, may be advantageous. This article will describe a research-based approach to enhancing the capacity of early childhood programs to gather and use a data-driven, team-based problem-solving model that relies on cloud computing tools. A description of a cloud-based knowledge management system for behavioral incident data will be provided along with descriptions of its use by a group of early childhood programs seeking to enhance their efficiency and effectiveness when addressing challenging behavior.
Treatment with low dose fasudil for acute ischemic stroke in chronic hypertension
Authors: Chan Siu-Lung , Cipolla Marilyn J
Published: July 2017

We investigated the effect of Rho kinase inhibition on changes in cerebral blood flow (CBF), brain injury and vascular function after ischemic stroke in spontaneously hypertensive rats (SHR). Changes in core MCA and collateral perfusion were measured by a validated laser Doppler method. Animals underwent 2 h tMCAO and 2 h reperfusion. Fasudil (0.1 mg/kg, i.v.) or vehicle was given at 30 min ischemia (n = 9/group; mean (SD)). Brain injury was determined by 2,3,5-triphenyltetrazolium chloride staining. To determine the effect of fasudil on vascular function, fasudil was given 10 min before reperfusion and parenchymal arterioles studied isolated (n = 6/group; mean(SD)). Collateral perfusion was low in vehicle-treated SHR (−8(32)%) that changed minimally with fasudil (6(24)%, p > 0.05, effect size: 0.47;95% CI−0.49–1.39). Reperfusion CBF was below baseline in vehicle (−27(26)%) and fasudil (−32(25)%, p > 0.05, effect size: 0.19; 95% CI−0.74–1.11) groups, suggesting incomplete reperfusion in both groups. Fasudil had little effect on brain injury volume (28(13)% vs. 36(7)% in vehicle, p > 0.05, effect size: 0.75; 95% CI−0.24–1.66). In isolated parenchymal arterioles, myogenic tone was similar between groups (37(6)% vs. 38(10)% in vehicle, p > 0.05, effect size: 0.09; 95% CI−1.05–1.21). There were no differences with fasudil treatment vs. vehicle in perfusion, brain injury and vascular function that may be related to the low dose that had minimal blood pressure lowering effect.