bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Evaluation of Inclusions in Bearing Steel
Authors: Muroi T , Nagasawa W , Narai H , Ohori M
Published: October 2006

The rolling contact fatigue (rcf) life of bearing steel is closely related to the steel cleanliness. To assess steel cleanliness, traditional methods such as optical image analysis and Statistics of Extreme Value are often used. The results obtained using these traditional methods of assessing steel cleanliness correlate well with the rcf life. More recently, pulse height distribution analysis (PDA) has been developed to determine steel cleanliness. Despite some issues surrounding the PDA method for assessing steel cleanliness, PDA is still considered to be superior to traditional methods for the quick assessment of nonmetallic inclusion in steels. A comparison has been made between the steel cleanliness results obtained by traditional optical image analysis and PDA to determine if the results of PDA can be used as a meaningful indicator of the rcf life of bearing steels. The comparison showed that the size of inclusions obtained by PDA agreed reasonably with the size of inclusion obtained using optical image analysis. Consequently, it should be possible to use the PDA results as an indicator of rcf life.
The Importance of Story-Telling: Research Protocols in Aboriginal Communities
Authors: Poff Deborah C.
Published: October 2006

An oral tradition and story telling culture are still central to aboriginal personal and community identity, and provide major means of remembering and conveying personal and community experience with university researchers. These stories describe stark accounts of betrayal and upset, as well as descriptions of positive experiences. They provide dramatic reminders to researchers of the importance of respectful and collaborative relationships with traditional community leaders and their members.
Essentials of the Disclosure Review Process: A Federal Perspective
Authors: Zarate Alvan O. , Zayatz Laura
Published: October 2006

Many researchers need to make arrangements to share de-identified electronic data files. However, the ways in which respondent identity may be protected are not well understood or are assumed to be the special province of large statistical agencies or specialized statisticians. Approaches to data sharing and protecting respondent identity have been pioneered by federal agencies which gather data vital to political and economic decision making. These agencies are required by statutory law both to assure confidentiality and to share data in usable form with other governmental agencies and with scholars who perform needed analyses of those data. The basic principles of disclosure limitation developed by the Census Bureau, the National Center for Health Statistics, and other federal agencies are fundamental to meeting new funding requirements to share and de-identify data, and are often referred to in the literature on data sharing. We describe how these principles are employed by the Disclosure Review Boards (DRBs) of these two agencies, and then state these principles in more general terms that are applicable to any disclosure review process. The kinds of data that academic institutions share may call for less complex or stringent DRBs and specific nondisclosure procedures different from those employed by federal agencies, but the same general principles apply. Specific application of these six principles by non-government researchers will depend on the nature of their data, their own institutional resources, and the likely future usefulness of their data.
Solving Problems of Disclosure Risk in an Academic Setting: Using a Combination of Restricted Data and Restricted Access Methods
Authors: Rodgers Willard , Nolte Michael
Published: October 2006

The health and retirement study collects a vast amount of information about a sample of the U.S. population over age 50 from biennial interviews, supplemental questionnaires, and through linkages with administrative data including Social Security earnings and benefits records and Medicare claims records. To honor its pledge to the respondents that their data will be kept confidential, but at the same time meet its objective of providing useful data to researchers, it has developed procedures for stripping sensitive information (i.e., information that could facilitate re-identification of sample members) from data sets that are publicly released, and also for providing mechanisms for qualified researchers to gain access to a variety of restricted-access data files. These mechanisms include a procedure whereby highly qualified researchers—in particular, only those who have a current grant from a federal agency—can apply to obtain restricted-access data sets for a limited amount of time, with the understanding that they will make no attempt to re-identify sample members and that they will be audited to ensure that they have adhered to the agreed-upon safeguards. For those who meet some but not all of the requirements for receiving these data, the files can be analyzed in a data enclave (a controlled, secure environment in which eligible researchers can perform analyses). This paper focuses on approaches to restricting data access that may need to be considered by investigators who plan to share their data, and by their institutional officials who will need to support that effort with appropriate infrastructure and policies. It also provides guidance to investigators and institutional review boards (IRBs) who seek access to restricted data generated and archived elsewhere.
Effect of Reduction in Water Salinity on Osmoregulation and Survival of Large Atlantic Salmon Held at High Water Temperature
Authors: Gonçalves J , Carraça S , Damasceno-Oliveira A , Fernández-Durán B , Diaz J , Wilson J , Coimbra J
Published: October 2006

We examined the possible ameliorating effects of reduced salinity (28‰) on the physiological performance of large Atlantic salmon Salmo salar initially reared at 35‰ and exhibiting osmo-ionoregulatory disturbances in high seasonal water temperatures (>18°C). Considerable differences were observed in the behavior, survival, and plasma values for cortisol, osmolality, and chloride after 3 d, with fish from the 28‰ salinity regime approaching basal levels (cortisol: 8.0 ± 1.7 mmol/L; osmolality: 374.3 ± 6.8 milliosmols per kilogram [mosmols/kg]; [Cl-]: 170.5 ± 3.8 mmol/L [mean ± SE]) and fish from full-strength seawater showing a further decrease in osmoregulatory capacity (cortisol: 33.7 ± 5.0 mmol/L; osmolality: 411.4 ± 9.7 mosmols/kg; [Cl-]: 189.1 ± 6.8 mmol/L). Two weeks later, fish kept at 28‰ still had a normal osmoregulatory capacity and exhibited a significant increase in condition factor, whereas many fish (70%) in full-strength seawater had died. These results indicate a limited capacity for maintaining osmo-ionoregulatory homeostasis in full-strength seawater during long periods at high temperature. Access to water of lower salinity appears to be essential for the survival of Atlantic salmon in this environment.
Effect of Feeding Strategies on Production Characteristics and Body Composition of Florida Pompano Reared in Marine Recirculating Systems
Authors: Weirich Charles R , Groat Derek R , Reigh Robert C , Chesney Edward J , Malone Ronald F
Published: October 2006

The effect of feeding strategies on production characteristics and body composition of Florida pompano Trachinotus carolinus reared using marine recirculating systems was evaluated in three growth trials (water temperature, 27–29°C; salinity, 23–28‰). A commercial diet (53% protein, 13% lipid) was fed in each trial. In trial 1, mean final weight of juveniles fed 5% of body weight per day (bw/d) in two, three, or six feedings for 38 d was significantly greater than that of Florida pompano fed once daily. In trial 2, Florida pompano that were fed twice daily to apparent satiation (AS) were significantly larger after 54 d than fish fed a fixed ration of 5% bw/d, regardless of initial stocking density (1.3 or 2.6 kg/m3). In trial 3, mean final weight of Florida pompano fed to AS four times daily for 133 d was significantly greater than that of fish fed to AS twice daily. Feeding rate and frequency did not affect feed conversion efficiency or body composition and had minimal effects on specific growth rate. Market-size pompano had dressed carcass yields greater than 70% and fillet yields greater than 45%. Juvenile pompano raised in recirculating systems in this study grew from an initial weight of 17 g to weights in excess of 450 g (market size) in 4–5 months and to weights in excess of 700 g in 8–9 months.
Zebra Mussels: Enhancement of Copper Toxicity by High Temperature and Its Relationship with Respiration and Metabolism
Authors: Rao D.G.V. Prasada , Khan M.A.Q.
Published: October 2006

Increase in water temperature from an ambient of 15 °C to 20 and 25 °C increased the respiration rate in zebra mussels, Dreissena polymorpha, by 50 and 175%, respectively, and increased the toxicity of copper; a 48‐hour lethal concentration to kill 50% of the organisms (LC50) of 775 μg/L at 20 °C decreased to 238 μg/L at 25 °C, and a 96‐hour LC50 of 487 μg/L at 20 °C reduced to 107 μg/L at 25 °C. The oxygen consumption rate in the presence of 150 μg/L copper decreased by 16% at 20 °C and by 50% at 25 °C. Thus, high temperatures may increase the toxicity of copper, and possibly other metals, to zebra mussels. Similar increases in heavy metal toxicity may also accompany global warming, which is expected to raise surface water temperature by 2 to 3 °C. Such temperature and heavy metal combinations may also be useful in designing field trials to control this nuisance species.
Anaerobic Biogranulation Using Phenol as the Sole Carbon Source
Authors: Tay Joo‐Hwa , He Yan‐Xin , Yan Yue‐Gen
Published: October 2006

The granulation process was extensively examined using phenol as sole carbon source in a 2‐L laboratory upflow anaerobic sludge blanket (UASB) reactor. The study was conducted mesophilically at 35 °C. Anaerobically digested sludge was used as seed after a 14‐day activation period with glucose feed. Massive initial granules were developed after 3 months of startup, grew at an accelerated pace for 6 months, then became fully grown. The granulation process can be broken into three phases: acclimation, granulation, and maturation. However, granulation with phenol proceeded more slowly than it did in UASB reactors fed with readily biodegradable carbohydrates studied previously. The granular sludge cultivated had a median diameter of 1.8 mm, phenol‐degrading activity of 0.65 g chemical oxygen demand (COD)/g volatile suspended solids (VSS)·d, and a sludge volume index of 14 mL/g. Phenol COD removal efficiency of 86% was achieved when the reactor was operating at an influent phenol concentration of 1260 mg/L (corresponding to 3000 mg COD/L), hydraulic retention time of 12 hours, and volumetric loading rate of 6 g COD/L·d. However, the lower‐than‐expected phenol COD removal efficiency could be attributed to inhibition by the high influent phenol concentration or loading. The batch test demonstrated that the sludge methanogenic activity was reduced by 52 and 75% at phenol concentrations of 420 and 840 mg/L, respectively.
Improving Aerobic Digestion by Prethickening, Staged Operation, and Aerobic–Anoxic Operation: Four Full‐Scale Demonstrations
Authors: Daigger Glen T. , Bailey Elena
Published: October 2006

Four full‐scale aerobic digesters were studied to determine the effects of prethickening, staged operation, and aerobic–anoxic operation on digester performance. Prethickening is expected to enhance aerobic digestion by reducing hydraulic flow rates, thereby allowing increased solids retention time (SRT) values and temperature elevation. Staged operation increases the plug flow characteristic of the digester, resulting in increased solids stabilization and pathogen destruction. Aerobic–anoxic operation results in denitrification, which can provide approximately neutral pH that enhances nitrification, digestion, and nitrogen removal. Results demonstrate that staging enhances digestion and reduces the SRT necessary to produce stabilized solids (i.e., one with a volatile solids reduction efficiency greater than 38% or a specific oxygen uptake rate less than 1.5 mg O2/g volatile suspended solids h). Effective pathogen destruction is also observed. Aerobic–anoxic operation at several facilities resulted in maintenance of approximately neutral pH values, enhanced digestion, near‐complete nitrification, and nitrogen removal. Prethickening resulted in autoheating at the Paris, Illinois, site, caused by the high concentration of biodegradable volatile solids in the digester feed, and at the Los Lunas, New Mexico, facility, which was specifically designed to maintain specified temperatures. The oxygen transfer capacity of the first stage must be adequate to meet the increased process oxygen requirement in that stage to allow increased digestion rates. A combination of low temperature and high solids concentration may interfere with oxygen transfer capacity. Excessive foaming can occur if adequate oxygen transfer capacity is not provided. Excellent performance can be achieved at SRT values in the 20‐ to 40‐day range at operating temperatures of 20 °C or greater.
Use of Hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine as a Nitrogen Source in Biological Treatment of Munitions Wastes
Authors: Brenner Asher , Ronen Zeev , Harel Yosi , Abeliovich Aharon
Published: October 2006

The purpose of this study was to develop a biological treatment process for the degradation of hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX), a nitramine explosive present in munitions manufacturing and processing wastes. A real waste mixture containing RDX, nitrate and nitrite (NO x), and several solvents (primarily cyclohexanone and acetone) was used as basic feed for bench‐scale experiments. Pure culture experiments indicated that bacteria can use RDX as a nitrogen source and organic solvents as carbon sources under aerobic conditions. In addition, it has been found that inorganic nitrogen compounds might interfere with the use of RDX as a nitrogen source. Because NOx are problematic constituents that should be removed anyway, anaerobic microbial denitrification was applied as a pretreatment stage to simultaneously remove NOx and organics and to form a nitrogen‐deficient environment for further aerobic degradation of RDX and residual organics. This conceptual approach was performed using two reactor systems: a two‐stage anaerobic–aerobic system and a single reactor with anaerobic and aerobic stages in its operation cycle. All laboratory reactors were operated in the sequencing batch reactor mode. Both systems achieved complete NOx removal in the denitrification stage with acetone serving as the carbon source and complete aerobic biodegradation of RDX with cyclohexanone serving as the carbon source.
Mineralogical and Physicochemical Methods To Differentiate Between Natural and Anthropogenic Sources of Chromium in Soils
Authors: Trupheme V. , Bousquet S. , Montrejaud‐Vignoles M. , Lacout J.L. , Fortune J.P. , Poujol T. , Cafferini N.
Published: October 2006

This study evaluates pollution from a former tannery by examining soils containing high concentrations of chromium (between 138 and 720 mg/kg dry matter according to the sample). This study presents an original methodology for characterizing chromium according to its two possible origins in soils: natural or anthropogenic. Conducting both a mineralogical study and a physicochemical study made it possible to clearly understand these origins. Natural chromium is particularly linked to pyroxenes, a primary mineral of the Massif Central, France, and found in large quantities in the samples studied. Anthropogenic chromium is adsorbed by vermiculites on their interfoliary sites. These clays possess a high capacity of cationic exchange and can thus attract chromium easily. In all of the samples studied, the naturally chromiferous mineral contribution was high (97 to 519 mg/kg dry matter), whereas that of the clays was low (41 to 201 mg/kg dry matter), indicating a smaller proportion of chromium introduced by humans. Natural chromium values are approximately 70 to 80%, whereas those for anthropogenic chromium are approximately 20 to 30%. This approach makes it possible to set realistic objectives for the cleanup of chromium‐contaminated soils.
Development of a Sulfate‐Reducing Biological Process To Remove Heavy Metals from Acid Mine Drainage
Authors: Steed Vicki S. , Suidan Makram T. , Gupta Munish , Miyahara Takashi , Acheson Carolyn M. , Sayles Gregory D.
Published: October 2006

The feasibility of using sulfate‐reducing bacteria to remove heavy metals from aqueous streams such as acid mine drainage was evaluated using three anaerobic reactors: an upflow anaerobic sludge blanket (UASB) reactor, a packed filter reactor, and a filter reactor that was partially packed with floating plastic pall rings. The packed filter reactors removed more than 99% of the influent metals. The performance of the partially packed reactor was superior based on effluent metal and sludge concentrations. Although the UASB reactor reduced the concentration of dissolved iron, the effluent concentration of total suspended solids remained greater than 18 g/L. This elevated solids concentration indicated that the UASB reactor was not operating as an effective clarifier, and, as a result, UASB reactor operation was discontinued after 4 months. The packed filter reactors were operated in parallel and received influent containing a combination of heavy metals. By withdrawing sludge from the bottom of these reactors, the accumulation of solids such as metal precipitates and biomass was controlled. The effluent concentrations of most metals were low, often less than drinking water standards, with the exception of manganese.
Surface Physical–Chemical Characteristics of Sludge Particulates
Authors: Wang Jianmin , Huang C.P. , Allen H.E.
Published: October 2006

The surface physical–chemical characteristics, specifically surface acidity and surface electrical properties of sludge particulates, govern the fate and transport of heavy metals in wastewater treatment systems. Surface acidity (i.e., site density and acidity strength) and surface electrical properties such as pH at the zero point of charge (pHzpc) and surface charge of primary, secondary, and tertiary sludge particulates were investigated. Alkalimetric titration was used to determine the surface site density and acidity constant. Electrophoresis was used to determine the surface electrical characteristics. Results show that the sludge surface site can be treated as a weak monoprotic acid under neutral and low pH conditions. The site density (Λm) was determined to be 2.4 × 10−3 mol/g suspended solids (SS) for primary sludge and 1.7 × 10−3 mol/g SS for secondary and tertiary sludges. The acidity constant ( pKH) was estimated to be 6.1 ± 0.5 for all sludge particulates studied. Results also showed that all sludge particulates have strong affinity toward metal ions, including potassium, sodium, and lithium ions. At the field ionic strength, the pHzpc value was approximately 2.9 ± 0.3 for all sludge particulates investigated. It was also revealed that the carboxyl moiety is the major surface functional group contributing the surface characteristics. The significance of surface physical– chemical characteristics of sludge particulates is exemplified by the metals uptake as effected by pH.
Nonsteady‐State Modeling of Multispecies Activated‐Sludge Processes
Authors: de Silva D.G. Viraj , Rittmann Bruce E.
Published: October 2006

A nonsteady‐state, multispecies model tracked reactor volume and 12 species critical for describing changes in soluble chemical oxygen demand (COD), biomass types, and nitrogen. Key to the model is its systematic partitioning of COD. The COD in all electron donors is partitioned among biomass synthesis, respiration to an electron acceptor, and soluble products released. Biomass decay is divided into respiration for maintenance energy, formation of inert biomass, and release of soluble products. Soluble products can be used as electron donors by heterotrophs, which are capable of using oxygen, nitrite, or nitrate as electron acceptors. Two modeling examples illustrate key features of the model. These demonstrate the importance of soluble products in controlling the soluble COD and indicate that different biomass types require different times to reach steady state and that a sequencing batch reactor reaches a global steady state in which concentrations of soluble species change dramatically within a cycle but biomass concentrations change relatively little.
Application of a Three‐Dimensional Electrode to the Electrochemical Removal of Copper and Zinc Ions from Diluted Solutions
Authors: Paidar Martin , Bouzek Karel , Laurich Michal , Thonstad Jomar
Published: October 2006

Electrochemical removal of copper and zinc ions from synthetic solutions simulating drainage water flowing from abandoned mines was studied. A three‐dimensional cathode was suitable for this purpose. Use of graphite felt electrodes in deoxygenated solution reduced the copper concentration in the solution from 150 to less than 0.05 mg/cubic decimeter (dm3) with a current efficiency of 68%. For successful zinc removal, it was necessary to increase the pH of the solution to values ≥10 to suppress the parasitic hydrogen evolution reaction. At these conditions, the zinc concentration in the solution could be reduced from 200 to 1.1 mg/dm3 with a current efficiency of 65%. Using a stainless steel wool cathode under identical conditions, a comparable current efficiency was achieved, but the outlet concentration of heavy metal ions increased to 22.1 mg/dm3.
Aerobic–Anaerobic Microbial Wastewater Transformations and Re‐aeration in an Air‐Injected Pressure Sewer
Authors: Tanaka Naoya , Hvitved‐Jacobsen Thorkild , Ochi Takatoshi , Sato Noriyoshi
Published: October 2006

Wastewater quality changes and re‐aeration during transport in an air‐injected pressure sewer (force main) were studied. Samples were taken from an air‐injected pressure sewer located in the northern part of Japan. The study focused on the transformations of wastewater organic matter as characterized by measurements of oxygen uptake rate. Wastewater was maintained under aerobic conditions by injecting air, which controlled sulfide formation and removed readily biodegradable substrate (SS) by aerobic microbial processes. To preserve SS, it was necessary to decrease dissolved oxygen concentration by reducing air‐injection flow rate. An aerobic–anaerobic wastewater process model for the air‐injected pressure sewer was established, and model parameters were determined based on experimental findings. It was possible to simulate transformations of wastewater organic matter, dissolved oxygen, and sulfide. The model can be applied to determine an appropriate air‐injection flow rate to control sulfide formation and reduce SS removal.
Determination of Kinetic Parameters of Ozone During Oxidations of Alachlor in Water
Authors: Beltrán Fernando J. , González Manuel , Rivas F. Javier , Acedo Benito
Published: October 2006

A study of the ozonation of the herbicide alachlor in distilled and surface water was performed. The influence of variables, including pH, water type, and free‐radical‐inhibiting substances, on the removal rate of alachlor was investigated. Alachlor was primarily removed from water through hydroxyl radical oxidation because low pH and the presence of natural substances such as carbonates significantly reduced the alachlor removal rate. Hydrogen peroxide was formed in low concentration during ozonation. Rate constants of the reactions between alachlor and ozone and between alachlor and the hydroxyl radicals were found to be 2.8 and 3.2 × 1010 L/mol·s, respectively. Because combined UV radiation and ozonation constitute one of the possible ozonation processes to treat alachlor, the quantum yield of this herbicide was determined and found to be 0.177 mol/einstein, which is a significant value compared to others found for different herbicides.
Biological Decolorization of the Azo Dye Reactive Red 2 Under Various Oxidation–Reduction Conditions
Authors: Beydilli M. Inan , Pavlostathis Spyros G. , Tincher Wayne C.
Published: October 2006

The decolorization of the azo dye reactive red 2 (RR2) was investigated under aerobic, anoxic, and methanogenic conditions. The dye was not decolorized by an aerobic culture kept under aerobic conditions for 7 days. However, incubation of the same culture under anoxic conditions resulted in RR2 decolorization with an initial rate of 40 mg/L·d and to an extent of 91.7% after the culture oxidation–reduction potential (ORP) dropped to less than ‐50 mV. A second addition of RR2 to the same culture kept under anoxic conditions resulted in a greater initial RR2 decolorization rate (86 mg/L·d) at an ORP value of –250 mV. Decolorization of RR2 at an initial dye concentration of 300 mg/L was achieved by an unacclimated methanogenic culture at an initial rate of 83 mg/L·d and without any inhibition. However, as a result of acclimation, initial RR2 decolorization rates of 523 and 1050 mg/L·d were achieved by the same methanogenic culture after 5 months and 2 years of weekly additions of 300 mg/L RR2, respectively. Dye decolorization followed Michaelis–Menten kinetics. Under methanogenic conditions and at an initial dye concentration of 300 mg/L, the maximum RR2 decolorization rate per unit biomass was 0.12 and 0.70 mg RR2/mg volatile suspended solids d without acclimation and after a 2‐year acclimation, respectively. Lack of significant RR2 decolorization was observed in autoclaved methanogenic culture controls. Therefore, the reductive cleavage of the dye azo bond resulting in the decolorization of RR2 and formation of aromatic amines was biologically mediated and is attributed to the reduced conditions created and maintained by the anoxic and anaerobic cultures. Thus, biological decolorization of reactive azo dyes is feasible under anoxic–anaerobic conditions and should be further explored for textile wastewater management.
Bound Water Content of Activated Sludge and Its Relationship to Solids Retention Time, Floc Structure, and Surface Properties
Authors: Liao B.Q. , Allen D.G. , Droppo I.G. , Leppard G.G. , Liss S.N.
Published: October 2006

The bound water (BW) content of sludge from four bench‐scale sequencing batch reactors (SBRs), fed a glucose‐based synthetic wastewater and operated at different solids retention times (SRTs), and from five full‐scale, activated‐sludge systems treating different wastewater was determined using the dilatometric technique. Storing sludge at 4 °C before analysis resulted in a lower measured BW value. The SRT and surface charge were not correlated to the BW content of sludge from the bench‐scale SBRs (SRT range of 4 to 20 days) or full‐scale systems (SRT range of 4 to 25 days). A greater BW content was strongly associated with a smaller median floc size in bench‐ and full‐scale studies, indicating the importance of floc size in relation to the BW content. In bench‐scale studies, greater levels of total extracellular polymeric substances (EPS) correlated with an observed increase in the BW content of sludge. Individual EPS components either weakly correlated to or were not associated with changes in BW. Sludge samples from the bench‐scale SBRs with greater BW content were found to have greater sludge volume index values. For the full‐scale systems studied, there was no relationship between EPS and BW content of the sludge.
A Modeling Study of Fouling Development in Membrane Bioreactors for Wastewater Treatment
Authors: Liang Shuang , Song Lianfa , Tao Guihe , Kekre Kiran Arun , Seah Harry
Published: October 2006

Membrane fouling is a primary concern in membrane bioreactors (MBRs) in wastewater treatment because it strongly affects both system stability and economic feasibility. A mathematical model was developed in this study for membrane fouling in submerged MBR systems for wastewater treatment, in which both reversible and irreversible fouling were quantified. While mixed liquor suspended solids are the major components of the reversible fouling layer, dissolved organic matter is thought to be the key foulant, in particular, responsible for the long‐term irreversible fouling of the filtration unit. The model was calibrated (parameter identification) with a set of operational data from a pilot MBR and then verified with other independent operational data from the MBR. The good agreement between theoretical predictions and operational data demonstrates that the outlined modeling concept can be successfully applied to describe membrane fouling in submerged MBR systems.
Treatment of Oily Port Wastewater Effluents Using the Ultraviolet/Hydrogen Peroxide Photodecomposition System
Authors: Siedlecka Ewa Maria , Stepnowski Piotr
Published: October 2006

This paper presents the nonselective degradation of mechanically pretreated oily wastewater by hydrogen peroxide (H 2O 2) in the presence and absence of UV irradiation. The effect of chemical oxidation on wastewater biodegradability was also examined. The exclusive use of H 2O 2 photolyzed by daylight results in quite efficient degradation rates for the low peroxide concentrations used. Higher hydrogen peroxide concentrations inhibit degradation of organic contaminants in the wastewater. The degradation rates of all contaminants are relatively high with an advanced oxidation system (UV/H 2O 2), but degradation efficiencies are not distinguishably different when 20 or 45 minutes of UV irradiation is used. The excess of H 2O 2 used in the process can inhibit phenolic degradation and may lead to the formation of a new phenolic fraction. The biodegradability of port wastewater did not increase significantly following the application of the advanced oxidation process.
Removal of Aqueous Nickel (II) Using Laterite as a Low‐Cost Adsorbent
Authors: Mukherjee Somnath , Kumar Sunil , Misra A. K. , Acharya P. C.
Published: October 2006

The present paper describes the laboratory study of laterite as a low‐cost adsorbent for removal of aqueous nickel (II). At pH 7 and a temperature of 30°C, a sorbent dose of 15 mg/L resulted in approximately 90% removal of nickel (II) from its initial concentration of 10 mg/L. A maximum removal of 98% of the adsorbate was observed with an adsorbent particle size of 210 μ with the above conditions. Batch kinetics results were described by fitting in a Langmuir isotherm. Helffrich's half‐time equation (Helffrich, 1962) has been applied to evaluate the adsorption process. It appears that film diffusion would be the rate‐limiting step. The effect of pH on the sorption process was carried out to a value of 8.0. The removal rate of nickel was found to be the function of pH of the reaction mixture. The rate of nickel uptake by laterite with the decrease in pH value has been explained on the basis of aqueous‐complex formation and the subsequent acid‐base dissociation at the solid‐solution interface.
Stormwater Quality Benefits of a Porous Friction Course and Its Effect on Pollutant Removal by Roadside Shoulders
Authors: Barrett Michael E. , Kearfott Pam , Malina Joseph F.
Published: October 2006

This project has two main objectives; the first is to documents the effect of a porous friction course overlay on the quality of highway stormwater runoff, and the second is to assess pollutant removal of a vegetated area along the side of a road from both conventional and porous pavements. The quantity and quality of stormwater runoff from a four‐lane divided highway in the Austin, Texas, area was monitored before and after the installation of a porous friction course (PFC). Observed concentrations of suspended solids and pollutants associated with particulate material were much lower in the runoff from the PFC compared with runoff from the conventional asphalt surface. The vegetated highway shoulder reduced the concentrations of many stormwater constituents from the conventional asphalt surface; however, the concentrations of these constituents in runoff produced by the PFC were so low that the vegetated area produced no further reduction in concentration.
Simultaneous Nitrification and Denitrification with Anoxic Phosphorus Uptake in a Membrane Bioreactor System
Authors: Patel Jignesh , Nakhla George
Published: October 2006

The performance of an innovative membrane bioreactor (MBR) process using anoxic phosphorus uptake with nitrification and denitrification for the treatment of municipal wastewater with respect to operational performance and effluent quality is addressed in this paper. The system was operated at steady‐state conditions with a synthetic acetate‐based wastewater at a hydraulic retention time (HRT) of 12 hours and on degritted municipal wastewater at a total system HRT of 6 hours. The MBR system was able to achieve 99% biochemical oxygen demand (BOD), chemical oxygen demand (COD), and ammonia‐nitrogen (NH4 +‐N); 98% total Kjeldahl nitrogen (TKN); and 97% phosphorus removal, producing effluent BOD, COD, NH4 +‐N, TKN, nitrate‐nitrogen, nitrite‐nitrogen, and phosphate‐phosphorus of <3, 14, 0.2, 0.26, 5.8, 0.21, and <0.01 mg/L, respectively, at the 6‐hour HRT. The comparison of the synthetic and municipal wastewater run is presented in this paper. Steady‐state mass balance on municipal wastewater was performed to reveal some key features of the modified MBR system.
Removal of Pyrene and Benzo(a)Pyrene from Contaminated Water by Sequential and Simultaneous Ozonation and Biotreatment
Authors: Yerushalmi Laleh , Nefil Sabria , Hausler Robert , Guiot Serge R.
Published: October 2006

The removal of pyrene and benzo(a)pyrene from contaminated water by sequential and simultaneous ozonation‐bioremediation techniques was investigated. During the sequential treatment, ozonation using 0.5 or 2.5 mg/L ozone was used as a pretreatment process, whereas, during the simultaneous treatment process, ozonation of hydrocarbon‐contaminated water at a predetermined duration using 0.5 mg/L ozone was made in the presence of microbial biomass. Ozonation was not beneficial for the removal of pyrene. However, despite a decreased specific biodegradation rate, ozonation improved the overall elimination of benzo(a)pyrene during both treatment processes. The overall removal of benzo(a)pyrene increased from 23 to 91% after exposure of the water to 0.5 mg/L ozone for 30 minutes during the simultaneous treatment process and further to 100% following exposure to 2.5 mg/L ozone for 60 minutes during the sequential treatment mode, demonstrating the benefits of combined ozonation‐biological treatment for the removal of polycyclic aromatic hydrocarbons.
Removal of Noro‐ and Enteroviruses, Giardia Cysts, Cryptosporidium Oocysts, and Fecal Indicators at Four Secondary Wastewater Treatment Plants in Sweden
Authors: Ottoson J. , Hansen A. , Westrell T. , Johansen K. , Norder H. , Stenström T. A.
Published: October 2006

The aim of this study was to investigate variation in the occurrence and removal of enteroviruses, noroviruses, Giardia cysts, Cryptosporidium oocysts, and the most commonly used fecal indicators in four Swedish secondary wastewater treatment plants (WWTPs). Paired samples were taken from the inlet and outlet of each WWTP. (Oo)cysts and indicators were enumerated with standard methods and viruses with a reverse transcriptase polymerase chain reaction. Giardia cysts and enteroviruses were constantly detected (mean numbers were 10 3.31 cysts and 10 4.44 polymerase chain reaction (PCR) units L −1, respectively). Oocysts were found in 5 out of 19 samples (mean number was 20 L −1). Noroviruses were found between November and February, with an average titer of 10 3.29 L −1. Mean cyst removal was 2.6 log, while noroviruses and enteroviruses were removed by 0.9 and 1.3 log, respectively. There was no correlation between the removals of pathogens and indicators (p > 0.05). Coliphage removal resembled human viral removal better than did F‐specific phage.
Thermal Hydrolysis of Secondary Scum for Control of Biological Foam
Authors: Jolis Domènec , Marneri Matina
Published: October 2006

Thermal hydrolysis of secondary scum at 9 bars and 170°C was shown to completely destroy Gordonia sp. cells and reduce its foaming potential, so that it can be recycled to headworks or sent to the solids‐handling side of the plant without the risk of causing foaming problems in the activated sludge system and anaerobic digesters. This process shows promise for biological foam control in wastewater treatment plants where solids retention time control and selective wasting cannot be applied and/or selector installation is not possible. An initial cost comparison of thermal hydrolysis and several widely accepted foam‐management strategies shows it to be competitive; however, optimization of operating pressure and temperature is necessary.
Full‐Scale Class A Biosolids Production by Two‐Stage Continuous‐Batch Thermophilic Anaerobic Digestion at the Hyperion Treatment Plant, Los Angeles, California
Authors: Iranpour Reza , Cox Huub H. J. , Fan Steve , Abkian Varouj , Minamide Traci , Kearney Ray J. , Haug Roger T.
Published: October 2006

The City of Los Angeles Hyperion Treatment Plant (HTP) (California) converted its anaerobic digesters to thermophilic operation to produce Class A biosolids. Phase IV tests demonstrated compliance of a two‐stage, continuous‐batch process with Alternative 1 of U.S. Environmental Protection Agency 40 CFR Part 503 (U.S. EPA, 1993), which defines the time–temperature requirement for batch treatment (T ≥ 56.3°C at 16‐h holding). Fecal coliforms, Salmonella sp., viable helminth ova, and enteric viruses were not detected in biosolids in the postdigestion train, including the truck‐loading facility and the farm for land application as the last points of plant control where compliance is to be demonstrated. The same results were achieved during Phase V tests, after lowering the second‐stage holding temperature to 52.6°C to reduce the elevated methyl mercaptan production that was observed during Phase IV. Hence, the Phase V process complied with Alternative 3 of 40 CFR Part 503. Currently, HTP operates its digesters under the same conditions as tested in Phase V. In 2003, monthly monitoring of the biosolids at the truck‐loading facility and the farm for land application demonstrated consistent compliance with Alternative 3.
Improving Adolescent Students' Reading Comprehension with Istart
Authors: McNamara Danielle S. , O'Reilly Tenaha P. , Best Rachel M. , Ozuru Yasuhiro
Published: October 2006

This study examines the benefits of reading strategy training on adolescent readers' comprehension of science text. Training was provided via an automated reading strategy trainer called the Interactive Strategy Trainer for Active Reading and Thinking (iSTART), which is an interactive reading strategy trainer that utilizes animated agents to provide reading strategy instruction. Half of the participants were provided with iSTART while the others (control) were given a brief demonstration of how to self-explain text. All of the students then self-explained a text about heart disease and answered text-based and bridging-inference questions. Both iSTART training and prior knowledge of reading strategies significantly contributed to the quality of self-explanations and comprehension. Adolescents with less prior knowledge about reading strategies performed significantly better on text-based questions if they received iSTART training. Conversely, for high-strategy knowledge students, iSTART improved comprehension for bridging–inference questions. Thus, students benefitted from training regardless of their prior knowledge of strategies, but these benefits translated into different comprehension gains.
The Computer Aversion, Attitudes, and Familiarity Index (CAAFI): A Measure for the Study of Computer-Related Constructs
Authors: Schulenberg Stefan E. , Yutrzenka Barbara A. , Gohm Carol L.
Published: October 2006

The purpose of this study was to systematically develop an instrument to measure computer aversion, computer attitudes, and computer familiarity. The study is an extension of previous research (Schulenberg, 2002). Development involved item generation, pilot testing, and exploratory and confirmatory factor analyses. The measure was administered to psychology students drawn from two universities ( N = 854; N = 400, respectively). The three hypothesized factors emerged, as well as an additional computer aversion factor. The measure possesses good content validity and factorial validity, as well as solid internal consistency reliability. Implications of this study, considerations, and directions for future research are discussed.
Addressing Gender Differences in Computer Ability, Attitudes and Use: The Laptop Effect
Authors: Kay Robin
Published: October 2006

The impact of gender on computer related attitudes, ability, and use has been actively documented, but little research has been done examining how to modify and reduce imbalances. The purpose of this study was to explore the effect of ubiquitous computing (24-hour access to a laptop and the Internet) on gender differences in pre-service teachers with respect to computer attitudes, ability, and use. Regarding computer attitudes, gender differences before the laptop program were observed in only one of the four constructs assessed: future intentions to use computers (behavioral attitude). There were no significant differences in attitude between males and females after the laptop program. With respect to computer ability, males reported having stronger skills in five of the ten ability constructs assessed before the laptop program (operating systems, database software, creating a web page, and programming). There were no significant gender differences in ability after the laptop program, with the exception of programming which continued to favor males. It is speculated that the gender equalization effect observed in this study could have a significant impact on the extent to which technology is used by future students, especially given recent trends in promoting the use of technology in the classroom.
Courseware Copyright: Whose Rights are Right?
Authors: Zhang Ke , Carr-Chellman Alison A.
Published: October 2006

This article discusses the difficult issues of balancing faculty and university rights and responsibilities regarding courseware developed either as commissioned or non-commissioned work in higher education. The article addresses the varied concerns among university personnel and higher education institutions, reviews two major models for developing institutional courseware copyright policies, and investigates related policies at three major universities in the United States. The investigation and discussion focus on how these policies may affect higher education institutions and instructional design faculty and service instructional designers in universities.
Dreams as the Expression of Conceptions and Concerns: A Comparison of German and American College Students
Authors: Domhoff G. William , Meyer-Gomes Katrin , Schredl Michael
Published: October 2006

Past research shows there are more similarities than differences in the dream content of college students in several industrialized democracies. This study uses new results from dreams collected in Germany to support this past finding and suggest that dreams are more similar than different because they dramatize people's conceptions and concerns in relation to personal issues, which probably do not vary as much from country to country as culture does. It is further argued that this continuity between dream content and waking concerns, when combined with other parallels between dreaming and waking cognition, can be used to develop a cognitive theory of dreams. In addition, suggestions for future research with college students in Germany, the United States, and other countries are presented as a way to link personal conceptions and cultural changes.
Radiation, Ecology and the Invalid LNT Model: The Evolutionary Imperative
Authors: Parsons Peter A.
Published: October 2006

Metabolic and energetic efficiency, and hence fitness of organisms to survive, should be maximal in their habitats. This tenet of evolutionary biology invalidates the linear-no-threshold (LNT) model for the risk consequences of environmental agents. Hormesis in response to selection for maximum metabolic and energetic efficiency, or minimum metabolic imbalance, to adapt to a stressed world dominated by oxidative stress should therefore be universal. Radiation hormetic zones extending substantially beyond common background levels, can be explained by metabolic interactions among multiple abiotic stresses. Demographic and experimental data are mainly in accord with this expectation. Therefore, non-linearity becomes the primary model for assessing risks from low-dose ionizing radiation. This is the evolutionary imperative upon which risk assessment for radiation should be based.
Helicobacter pylori infection can modulate the susceptibility of gastric mucosa cells to MNNG
Authors: Arabski Michał , Kazmierczak Paweł , Wiśniewska-Jarosińska Maria , Morawiec Zbigniew , Morawiec-Bajda Alina , Klupińska Grażyna , Drzewoski Józef , Chojnacki Jan , Błasiak Janusz
Published: October 2006

The pathogenesis of stomach cells can be associated with their susceptibility to exogenous dietary irritants, like nitrosamines such as dimethylnitrosamines (DMNA), and to the effects of non-dietary factors, including Helicobacter pylori infection. We used N-methyl-N’-nitro N-nitrosoguanidyne (MNNG) as a surrogate agent that induces a spectrum of DNA damage similar to DMNA. Using the alkaline comet assay, we showed that antioxidants — vitamins C and E, quercetin, and melatonin — reduced the genotoxic effect of MNNG in H. pylori-infected and non-infected human gastric mucosa cells (GMCs). To compare the sensitivity of the stomach and the blood, the experiment was also carried out in peripheral blood. We observed a higher level of DNA damage induced by MNNG in H. pylori-infected than in noninfected GMCs. We did not note any difference in the efficacy of the repair of the damage in either type of GMC. H. pylori infection may play an important role in the pathogenesis of GMCs, as it can modulate their susceptibility to dietary mutagens/carcinogens, thus contributing to gastric cancer.
Chi‐Squared Tests—II
Authors: Nikulin Mikhail , Voinov Vassilly
Published: October 2006

Chi‐squared goodness‐of‐fit tests for parametric families of distributions are discussed. Different methods of unknown parameters estimating are compared and some modifications of the Pearson statistic depending on methods of estimation are discussed.
Financial Time Series
Authors: Tsay Ruey S.
Published: October 2006

Financial time series analysis is concerned with theory and practice of asset valuation over time. This article introduces key features and properties of financial time series and discusses econometric and statistical methods available for analyzing such series. It also discusses recent developments in financial time series analysis in the advent of high‐frequency transaction data and in estimation of stochastic diffusion equations for derivative pricing.
Hazard Rate Estimation
Authors: Veraverbeke Noël
Published: October 2006

The literature on the topic of hazard rate estimation is reviewed. Most results are developed for randomly right censored sample data and the most popular estimators are of the kernel type. The choice of the smoothing parameter is an important issue. The incorporation of covariate information is also considered.