bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using chlorite ion to control nitrification
Authors: McGuire Michael J. , Lieu Nancy I. , Pearthree Marie S. 
Published: February 2018

Laboratory and field studies of five Texas distribution systems suggest that chlorite ion has significant potential for controlling nitrification in chloraminated water.Controlling nitrification is essential if chloramines are to be a viable alternative disinfectant scheme for distribution systems in all types of environments. This article reviews problems associated with nitrification and presents laboratory and field evidence for using the chlorite ion (ClO2–) to control nitrification in distribution systems. Laboratory experiments in this study showed that even low dosages of ClO2– (0.05 mg/L) can inactivate 3–4 logs of ammonia‐oxidizing bacteria (AOB) over several hours. Higher concentrations of ClO2– inactivate all of the AOB in as little as 30 minutes. Field investigations at five Texas water utilities showed that the presence of ClO2– in the distribution systems resulted in less loss of chloramines and ammonia–nitrogen and thus less nitrification than in those systems in which ClO2– was not present. The ease of use of ClO2– is compared with other, more traditional nitrification control measures.
Factors affecting filtered water turbidity
Authors: Lusardi Peter J. , Consonery Phil J. 
Published: February 2018

A study of 75 filtration plants found that operator awareness and commitment to excellence may be more important to performance than key water quality, design, and operational variables.Approximately 8 million of Pennsylvania's 12 million residents receive water from 329 surface water treatment plants. This study evaluated the performance of a subset of these plants to determine whether they are prepared to meet the turbidity treatment technique requirements of the Enhanced Surface Water Treatment Rule. Using 75 filtration plants, the authors reviewed key water quality, design, and operational variables to determine their effect on filtered water turbidity. Except for plants that did not use a coagulant, served populations of < 3,300 people, or used streams for source water, there was no strong statistical correlation between any of the variables and filtered water turbidity. Many plants were able to consistently achieve low turbidity levels despite limitations such as small system size, plant age, or high source water turbidity. The results of this study show that intangible variables such as commitment to achieving low turbidity, operator skill level, and operator attention appear to be more important than tangible variables such as source water quality, ownership type, plant age, coagulant type, and other operational or design factors.
Design and operation of high‐rate filters
Authors: Kawamura Susumu 
Published: February 2018

Practical observations improve the design and operation of filtration systems.Filtration is the fundamental system in a water treatment process train that removes suspended solids, including microorganisms such as Cryptosporidium oocysts, Giardia cysts, and parasite eggs. To constrain costs, the design of any filter should be simple, reliable, proven, easy to build, and easy to operate; and it should require the minimum capital, operation, and maintenance costs while providing maximum operational flexibility. A robust filter design should be based on knowledge, experience, and user feedback. This article provides practical guidance on the design of high‐rate filtration systems.
Alternative tests for evaluating NF fouling
Authors: DiGiano Francis A. , Arweiler Sabine , Riddick J. Arthur 
Published: February 2018

Two alternative batch tests use a smaller sample and simpler experimental setup.The batch recycle membrane test (BaReMT) and batch internal recycle membrane test (BaIReMT) were developed as simpler alternatives to the rapid bench‐scale membrane test (RBSMT) currently recommended by the Information Collection Rule for evaluating membrane treatment. All three methods were tested on a small (155‐cm2 [26‐sq‐in.]) flat sheet of membrane. Both the BaReMT and BaIReMT require a far smaller batch volume of water sample than does the RBSMT. The patterns of flux decline and recovery were similar in the BaReMT and RBSMT that used water treatment plant samples from Durham and Fayetteville, N.C. The fouling tendencies of water treatment plant samples from Durham, Fayetteville, and Raleigh, N.C. were similar. Although the mass of natural organic matter on the membrane was small, its estimated concentration in the foulant layer was large. Scanning electron and atomic force micrographs showed that not all foulants were removed from the membrane surface despite extensive cleaning. Only repeated cycles of cleaning can demonstrate the long‐term effect of the remaining foulants on flux recovery.
Sydney's 1998 water quality crisis
Authors: Clancy Jennifer L. 
Published: February 2018

Events in Sydney, Australia, illustrate the pitfalls of overreliance on pathogen monitoring data in making decisions about water treatment and public health.A drinking water quality crisis occurred in Sydney, Australia, from July through September 1998. High concentrations of Cryptosporidium oocysts and Giardia cysts were repeatedly observed in water samples collected in the distribution system, although no increase in waterborne disease was detected. The reported concentrations of both cysts and oocysts ranged from nondetects to thousands of parasites per 100 L of finished water. Based on these monitoring data, three boil‐water advisories were issued over a nine‐week period. A formal government inquiry was ordered to investigate the cause of the contamination. The author visited the facilities involved and found that the laboratory providing the monitoring data had significant quality assurance and quality control problems, rendering the protozoan data suspect. Furthermore, data from other laboratories indicated the original reports were in error. In the author's opinion, reliance on poor‐quality monitoring data created a water quality crisis when, in fact, no water quality problems or threats to public health existed.
Secondary effects of enhanced coagulation and softening
Authors: Carlson Ken , Via Steve , Bellamy Bill , Carlson Mark 
Published: February 2018

Enhanced coagulation and softening—while reducing the formation of DBPs—have secondary effects on water treatment processes that must be considered.The implementation of enhanced coagulation or enhanced softening, while reducing the formation of disinfection by‐products, will affect other treatment processes as a result of the associated changes in water chemistry and solids loading. Utilities that implement enhanced coagulation or softening will likely see secondary effects, which need to be anticipated and mitigated. The AWWA Water Industry Technical Action Fund sponsored an expert workshop with representatives from the utility, consulting, academic, and regulatory fields to identify and characterize the secondary effects of enhanced coagulation and softening and to recommend mitigation strategies. Workshop participants identified four process areas that could potentially be affected by the implementation of an enhanced coagulation or a softening process. Mitigation flowcharts are provided for each secondary effect to help utilities determine what if any course of action to pursue if enhanced coagulation or softening is implemented.
Detecting breaks in prestressing pipe wire
Authors: Atherton David L. , Morton Keith , Mergelas Brian J. 
Published: February 2018

A new electromagnetic technique for inspecting prestressed concrete pressure pipe enables nonintrusive inspection for even single broken prestressing wires.Prestressed concrete pressure pipe (CPP) is in widespread use throughout Canada and the United States, with a total of some 19,000 mi (30,000 km) of pipe in use in North America's major water utilities. Many of these lines are more than 50 years old, and half are expected to need repair or replacement over the next 20 years. To selectively maintain these lines and avoid costs from catastrophic pipe failures, utilities needed an inspection technique that was highly sensitive, reliable, effective, and economical. An innovative electromagnetic technique, based on the remote field eddy current (RFEC) inspection technique, has been developed that allows nonintrusive inspection of prestressed CPP. Full‐scale testing conducted on embedded cylinder pipes and bar‐wrapped pipelines demonstrated the new RFEC technique's sensitivity to both single and multiple breaks in prestressing wire.
Locating leaks with acoustic technology
Authors: Tafuri Anthony N. 
Published: February 2018

Researchers were able to pinpoint leaks as small as 0.1 gph using acoustic emission techniques.Many water distribution systems in this country are almost 100 years old. About 26 percent of piping in these systems is made of unlined cast iron or steel and is in poor condition. Many methods that locate leaks in these pipes are time‐consuming, costly, disruptive to operations, and unreliable at finding small leaks. This article presents the results of research conducted at the US Environmental Protection Agency's Urban Watershed Research Facility in Edison, N.J. The project sought ways to use acoustic technology to pinpoint leaks as small as 0.1 gph (0.1 mL/s) in petroleum pipelines, a regulatory requirement for those lines. Because all experiments were conducted using water and on pipelines of size and material similar to those found in many water distribution systems, results also apply to these pipelines. Although leaks of 0.1 gph (0.1 mL/s) are unusually small to search for in water distribution systems, researchers were able to locate small leaks within 1 ft (0.3 m), which is comparable to the best practice of commercially available leak‐pinpointing technology for water distribution systems.
The blue water phenomenon
Authors: Edwards Marc , Jacobs Sara , Taylor Russell J. 
Published: February 2018

Little is known for certain about the factors that initiate or propagate blue water, a perplexing copper corrosion problem.Extensive effort has been expended by utilities, consultants, and scientists to better understand factors causing outbreaks of blue water, a rare problem that occurs in relatively high pH drinking water. This work synthesizes information about initiation factors, remedial measures, and theories. Although chlorine is an effective remedial measure, little is known for certain about factors that initiate or propagate blue water.
Consumer response to public notification
Authors: Harding Anna K. , Anadu Edith C. 
Published: February 2018

A recent study offers utilities information that may help increase the effectiveness of their public notification programs.Residents of four Oregon communities were surveyed about their responses to public notification. In the two towns that had issued public notification in response to a water problem, most residents were aware of the notices and responded by boiling their water, drinking bottled water, or both. Residents in the town with a short‐term water problem were more likely than residents in the town with a long‐term problem to boil water. Most respondents in both towns favored drinking bottled water over boiling water, despite a boil‐water notice. The survey found that residents of these towns as well as those in two control communities considered the newspaper the primary source of information about their drinking water. The sources of information regarded as most reliable, however, were mail from the city water utility, followed by the county health department and newspapers. Most respondents reported they were willing to pay for drinking water improvements, particularly to correct chemical and microbiological contamination.
The plain, hard truth about pathogen monitoring
Authors: Allen Martin J. , Clancy Jennifer L. , Rice Eugene W. 
Published: February 2018

As a pretense for public health protection, pathogen monitoring is of little value and should be replaced by alternative strategies such as treatment optimization.Pathogen monitoring has concerned microbiologists for nearly a century. Over several years, numerous factors have inflated the value of pathogen monitoring for public health protection and led to such developments as the promulgation of the Information Collection Rule (ICR). Eighteen months of ICR data have only served to underscore the monitoring method's limitations. Methods 1622 and 1623 represent significant improvements but still fall short of providing information useful for compliance monitoring or public health decision‐making. To illustrate the shortcomings of pathogen monitoring, the authors cite recent cases in which poor‐quality analyses contributed to the creation of drinking water crises where none, in fact, existed. The authors propose that pathogen monitoring for protecting public health be replaced by alternative strategies such as optimizing treatment and maintaining water quality throughout storage and distribution.
Giardia and Cryptosporidium occurrence in groundwater
Authors: Moulton‐Hancock Carrie , Rose Joan B. , Vasconcelos G.J. , Harris Stephanie I. , Klonicki Patricia T. , Sturbaum Gregory D. 
Published: February 2018

Analysis of groundwater for the presence of microbiota offers researchers a way to estimate the potential for Giardia and Cryptosporidium contamination.A total of 383 groundwater samples from 166 different sites were analyzed for Cryptosporidium, Giardia, and other microbiota (1–500 μm) using immunofluorescence assay and light microscopy procedures. Analysis of the data showed 11 percent of the sites (19 of 166) were sometimes positive for Cryptosporidium, Giardia, or both. Statistical analyses determined that microbiota in eight major groups were indicative of Cryptosporidium and Giardia contamination. These groups include algae, arthropods, rotifers, fungi, nematodes, colorless flagellates, amoebae, and gastrotrichs. Cryptosporidium and Giardia occurrence also correlated positively with the three risk categories developed by the US Environmental Protection Agency to rank direct surface water influence on groundwaters (p = 0.001). However, the specific numerical scores used to determine risk categories provided no better prediction of the pathogens than the three general categories. To determine vulnerability to contamination, researchers first should investigate those groundwater sources with a diversity of microbiota.
Conventional and optimized coagulation for NOM removal
Authors: Bell‐Ajy Kimberly , Abbaszadegan Morteza , Ibrahim Eva , Verges Debbie , LeChevallier Mark 
Published: February 2018

Bench‐ and full‐scale experiments were conducted to evaluate the optimal coagulation conditions for removal of total organic carbon and disinfection by‐products.The evaluation of 16 sites with optimized coagulation (optimizing the pH of coagulation and then the coagulant dosage) provides an assessment of this coagulation technique and illustrates its capabilities to meet the requirements of the Disinfectants/Disinfection By‐products (D/DBP) Rule. Jar tests were used to determine the effectiveness of optimized coagulation for the removal of organic carbon, DBP precursors, particles, and turbidity when supernatant results were compared with conventional (baseline) treatment. Jar‐test results indicate that optimized coagulation can enhance the removal of organic carbon and DBP precursors.
The effect of hydroxyapatite nanoparticles on adipogenic differentiation of human mesenchymal stem cells
Authors: Yang Xing , Li Yuanyuan , Huang Qianli , Liu Xujie , Zhang Ranran , Feng Qingling 
Published: February 2018

AbstractDue to its excellent biocompatibility, nanosized hydroxyapatite (nHA) has drawn much attention for various applications in biomedical fields. There are growing concerns about its biosecurity; however, little is known about its effects on adipogenesis. In the present study, nHA with three different sizes were synthesized, and the in vitro effects of nHA on cell proliferation and adipogenic differentiation of human mesenchymal stem cells (hMSCs) were investigated. The results clearly show that nHA does not affect the cell viability, the lipids droplets formation, triglyceride (TG) synthesis, and the expression of adipogenic marker genes/proteins of hMSCs at concentrations lower than 50 μg/mL. It is concluded that the adipogenic differentiation potential of hMSCs is not affected by nHA at noncytotoxic concentrations. These will provide a reference for the applications of nHA in biomedical fields. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1822–1831, 2018.
Exploring acceptability of oral PrEP prior to implementation among female sex workers in South Africa
Authors: Eakle Robyn , Bourne Adam , Mbogua Judie , Mutanha Nyaradzo , Rees Helen 
Published: February 2018

AbstractIntroductionFemale sex workers (FSWs) are at high‐risk for HIV acquisition in South Africa, where the advent of new HIV prevention and treatment interventions represent the potential to significantly impact the epidemic. This paper focuses on aspects of PrEP acceptability as a new intervention within the context of a larger service delivery programme including the simultaneous rollout of early ART. This paper explores PrEP acceptability among the FGD participants as future potential users.MethodsFGDs were conducted in two clinic‐based sites in Johannesburg and Pretoria. They aimed to explore community‐level, multi‐dimensional acceptability of PrEP within the context of imminent implementation alongside early ART in the TAPS Demonstration Project. Sex worker peer educators recruited participants from varying sex work locales. Facilitation was in English with adaptation by facilitators into local languages as needed. Transcripts were translated and transcribed into English. Thematic analysis was used to analyse the data.ResultsFour FGDs were conducted in each site for a total of eight FDGs and 69 participants. Demographics were largely similar across the sites. Overall, there was strong acceptability of PrEP among participants and positive anticipation for the imminent delivery of PrEP in the local sex worker clinics. Themes arising from the discussions exploring aspects of PrEP acceptability included: awareness and understanding of PrEP; PrEP motivations including choice, control, and vulnerability, managing PrEP risks and worries; and, de‐stigmatizing and empowering PrEP delivery. Participant discussions and recommendations highlighted the importance of developing clear education and messaging to accurately convey the concept of PrEP, and intervention integration into supportive and tailored services.ConclusionsThrough the course of these FGDs, PrEP became a positive and highly anticipated prevention option among the FSWs participants who endorsed implementation in their communities. Effective integration of PrEP into existing services will include comprehensive health programming where ART is also available, appropriate messaging, and support.
Proximity effect in transient analysis of radio base stations
Authors: Chen Hongcai , Du Yaping 
Published: February 2018

AbstractThis paper presents an equivalent circuit model for calculating fast transient current distribution in radio base station system. The new model takes account of both skin and proximity effects in the simulation and achieves a fast computation by using an efficient discretization scheme. The obtained circuit is synthesized using a time domain solver, PSpice. The proposed method is validated experimentally and is applied to evaluate the lightning current in a practical radio base station. A practical system with a 20‐m tower and 7 cables is analyzed. Various surge protective devices (SPD) are installed among cables in the simulation. Comparison among different configurations reveals that proximity effect will lead to uneven current distribution in cables. Outer‐located cables will carry more currents than others which should be paid more attention.
Monostatic imaging of an embedded object using a confocal algorithm
Authors: Chouiti Sidi Mohammed , Merad Lotfi , Meriah Sidi Mohammed , Derraz Foued , Raimundo Xavier 
Published: February 2018

AbstractIn this paper, we present simulation results of monostatic configuration for microwave imaging system by using confocal algorithm to detect and localize metallic bars inserted in a concrete pillar. An ultra‐wideband antenna has been used. The dielectric property values of the model were chosen near those of the realities. However, we have changed the permittivity of the concrete pillar to study the effectiveness of the algorithm despite the introduction of different kind of concrete. Successful detection and localization of different shapes and positions of metallic bars of diameter as small as 4 mm are presented. The efficacy of the proposed algorithm was also demonstrated by adding noise to the backscattered signals before creating the image.
In vitro evaluation of controlled‐release 14% doxycycline gel for decontamination of machined and sandblasted acid‐etched implants
Authors: Patianna Giuseppe , Valente Nicola Alberto , D'Addona Antonio , Andreana Sebastiano 
Published: February 2018

AbstractBackgroundPeri‐implant infections are associated with the establishment and maturation of a bacterial biofilm characterized by a predominance of Gram‐negative fusiform anaerobic species. The decontamination of implant surfaces is then crucial for a successful peri‐implant therapy.MethodsTwenty‐one smooth and 21 rough implants, divided into four groups according to surface and treatment modality, were contaminated with Streptococcus sanguinis and then placed in an incubator with the atmosphere of 5% CO2 at 37°C for 24 hours to allow the bacteria to grow. After 24 hours, the test groups were treated with controlled release 14% doxycycline gel injecting the gel circumferentially over the surface of the implant for 3 minutes, while the control groups were irrigated with sterile saline for 1 minute. The implants were then vortexed into triptych soy broth to allow the bacteria to detach from the surface, diluted 1:100 and plated. Colony forming units (CFU) were counted 48 hours after incubation.ResultsThe use of a 14% doxycycline gel minimized CFU counts compared to control groups, with the difference being statistically significant (P < 0.05). The reduction of CFUs in the smooth test group is more marked than in the rough test group, but the difference doesn't reach statistically significance (P = 0.215).ConclusionsThe use of 14% doxycycline gel in implant surface decontamination was efficacious in this in‐vitro study. Adjunctive use of locally delivered 14% doxycycline gel might be a viable option in the management of peri‐implantitis and peri‐implant mucositis considering its efficacy in reducing bacterial colonization.