Chemical cleaning an essential part of steam generator asset management

International Nuclear Information System (INIS)

Amman, Franz

2008-01-01

Chemical Cleaning an essential part of Steam Generator asset management accumulation of deposits is intrinsic for the operation of Steam Generators in PWRs. Such depositions often lead to reduction of thermal performance, loss of component integrity and, in some cases to power restrictions. Accordingly removal of such deposits is an essential part of the asset management of the Steam Generators in a Nuclear Power Plant. Every plant has its individual condition, history and constraints which need to be considered when planning and performing a chemical cleaning. Typical points are: - Sludge load amount and constitution of the deposits - Sludge distribution in the steam generator - Existing or expected corrosion problems - Amount and tendency of fouling for waste treatment Depending on this points the strategy for chemical cleaning shall be evolved. the range of treatment starts with very soft cleanings with a removal of approx 100 kg per steam generator and goes to a full scale cleaning which can remove up to several thousand kilograms of deposits from a steam generator. Depending on the goal to be achieved and the steam generator present an adequate cleaning method shall be selected. This requires flexible and 'customisable' cleaning methods that can be adapted to the individual needs of a plant. Such customizing of chemical cleaning methods is an essential factor for an optimized asset management of the steam generator in a nuclear power plant

Three Mile Island Nuclear Station steam generator chemical cleaning

International Nuclear Information System (INIS)

Hansen, C.A.

1992-01-01

The Three Mile Island-1 steam generators were chemically cleaned in 1991 by the B and W Nuclear Service Co. (BWNS). This secondary side cleaning was accomplished through application of the EPRI/SGOG (Electric Power Research Institute - Steam Generator Owners Group) chemical cleaning iron removal process, followed by sludge lancing. BWNS also performed on-line corrosion monitoring. Corrosion of key steam generator materials was low, and well within established limits. Liquid waste, subsequently processed by BWNS was less than expected. 7 tabs

Waste processing of chemical cleaning solutions

International Nuclear Information System (INIS)

Peters, G.A.

1991-01-01

This paper reports on chemical cleaning solutions containing high concentrations of organic chelating wastes that are difficult to reduce in volume using existing technology. Current methods for evaporating low-level radiative waste solutions often use high maintenance evaporators that can be costly and inefficient. The heat transfer surfaces of these evaporators are easily fouled, and their maintenance requires a significant labor investment. To address the volume reduction of spent, low-level radioactive, chelating-based chemical cleaning solutions, ECOSAFE Liquid Volume Reduction System (LVRS) has been developed. The LVRS is based on submerged combustion evaporator technology that was modified for treatment of low-level radiative liquid wastes. This system was developed in 1988 and was used to process 180,000 gallons of waste at Oconee Nuclear Station

EM-31 Alternative and Enhanced Chemical Cleaning Program

International Nuclear Information System (INIS)

King, Bill

2010-01-01

King's introduction to his presentation made 5 important points: (1) Numerous SRS tanks scheduled for closure (contract commitments); (2) Cannot remove all sludge by mechanical means due to obstructions; (3) Chemical removal technology needed (likely oxalic acid); (4) Post - dissolution neutralization required prior to transfer to compliant tanks; (5) Sodium oxalate salts precipitate on neutralization and have negative downstream impacts. There were three SRS chemical cleaning programs in 2010: Baseline: 8wt percent OA batch contact, ECC: 1-3 wt. percent OA with oxalate destruction, and the Alternative/Enhanced Chemical Cleaning (EM-31). This talk is on the EM-31 program.

Chemical-cleaning process evaluation: Westinghouse steam generators. Final report

International Nuclear Information System (INIS)

Cleary, W.F.; Gockley, G.B.

1983-04-01

The Steam Generator Owners Group (SGOG)/Electric Power Research Institute (EPRI) Steam Generator Secondary Side Chemical Cleaning Program, under develpment since 1978, has resulted in a generic process for the removal of accumulated corrosion products and tube deposits in the tube support plate crevices. The SGOG/EPRI Project S150-3 was established to obtain an evaluation of the generic process in regard to its applicability to Westinghouse steam generators. The results of the evaluation form the basis for recommendations for transferring the generic process to a plant specific application and identify chemical cleaning corrosion guidelines for the materials in Westinghouse Steam Generators. The results of the evaluation, recommendations for plant-specific applications and corrosion guidelines for chemical cleaning are presented in this report

Power generation from chemically cleaned coals: do environmental benefits of firing cleaner coal outweigh environmental burden of cleaning?

DEFF Research Database (Denmark)

Ryberg, Morten W.; Owsianiak, Mikolaj; Laurent, Alexis

2015-01-01

Power generation from high-ash coals is a niche technology for power generation, but coal cleaning is deemed necessary to avoid problems associated with low combustion efficiencies and to minimize environmental burdens associated with emissions of pollutants originating from ash. Here, chemical...... beneficiation of coals using acid and alkali–acid leaching procedures is evaluated as a potential coal cleaning technology employing life cycle assessment (LCA). Taking into account the environmental benefits from firing cleaner coal in pulverized coal power plants and the environmental burden of the cleaning...... itself, it is demonstrated that for a wide range of cleaning procedures and types of coal, chemical cleaning generally performs worse than combustion of the raw coals and physical cleaning using dense medium separation. These findings apply for many relevant impact categories, including climate change...

Effectuality of Cleaning Workers' Training and Cleaning Enterprises' Chemical Health Hazard Risk Profiling

Directory of Open Access Journals (Sweden)

Abdulqadir M. Suleiman

2015-12-01

Conclusion: Training of cleaning workers lacks the prerequisite for suitability and effectiveness to counter risks of chemical health hazards. There is dereliction of duty by management in the sector resulting in a lack of competence among the cleaning workers. Instituting acceptable easily attainable safety competence level for cleaners will conduce to risk reduction, and enforcement of attainment of the competence level would be a positive step.

Chemical cleaning the service water system at a nuclear power plant

International Nuclear Information System (INIS)

Brice, T.O.; Glover, W.A.

1994-01-01

Chemical cleaning a large cooling water system in a nuclear power plant presented many unique problems. The selection, qualification, and performance of the cleaning process were done using a phased approach. The piping was inspected to determine the extent of the problem. Deposit samples were removed from the service water system pipe and tested in the laboratory to determine the most effective cleaning solvent for deposit removal. An engineering study was performed to define the design parameters required to implement the system-wide chemical cleaning

Medium scale test study of chemical cleaning technique for secondary side of SG in PWR

International Nuclear Information System (INIS)

Zhang Mengqin; Zhang Shufeng; Yu Jinghua; Hou Shufeng

1997-08-01

The medium scale test study of chemical cleaning technique for removing corrosion product (Fe 3 O 4 ) in secondary side of SG in PWR has been completed. The test has been carried out in a medium scale test loop. The medium scale test evaluated the effect of the chemical cleaning technique (temperature, flow rate, cleaning time, cleaning process), the state of corrosion product deposition on magnetite (Fe 3 O 4 ) solubility and safety of materials of SG in cleaning process. The inhibitor component of chemical cleaning agent has been improved by electrochemical linear polarization method, the effect of inhibitor on corrosion resistance of materials have been examined in the medium scale test loop, the most components of chemical cleaning agent have been obtained, the EDTA is main component in cleaning agent. The electrochemical method for monitor corrosion of materials during cleaning process has been completed in the laboratory. The study of the medium scale test of chemical cleaning technique have had the optimum chemical cleaning technique for remove corrosion product in SG secondary side of PWR. (9 refs., 4 figs., 11 tabs.)

Service water chemical cleaning at River Bend gets results

International Nuclear Information System (INIS)

Brice, T.O.; Glover, W.A.

1994-01-01

The largest known Service Water System (SWS) chemical cleaning ever performed at a nuclear plant was successfully completed at, River Bend Station. Corrosion product buildup was observed during system inspections in the first operating cycle and the first refueling outage in 1987. Under deposit corrosion was followed with microbiologically influenced corrosion (MIC) occurring as a later stage under deposits. The heavy corrosion caused blockage of heat exchanger tubes, fouling of valve seats, and general flow blockage throughout the system. Various options were evaluated for restoring the SWS back to an acceptable long term operating condition. The large scale chemical cleaning performed arrested the corrosion by removing the deposits down to the bare metal surfaces and leaving behind a protective passivation layer. After the cleaning, the open recirculating SWS was converted to a closed system. The implementation of a molybdate/nitrate water treatment program with a copper corrosion inhibitor maintained at a high pH (8.5--10.5) has significantly reduced corrosion rates in the closed system. This should extend the life of the SWS piping for the remaining life of the plant. Several field tests were conducted to qualify the process and demonstrate its ability to achieve acceptable cleaning results prior to being used on a larger scale. In the summer of 1992, temporary and permanent modifications were installed to divide the SWS into two separate cleaning loops for the system wide cleaning. The SWS chemical was successfully performed and completed on schedule during the fourth refueling outage. Post cleaning inspections at various locations throughout the Service Water System showed the process to be very effective at complete deposit removal

Chemical cleaning of AGR boilers

International Nuclear Information System (INIS)

Moore, S.V.; Moore, W.; Rantell, A.

1978-01-01

AGR boilers are likely to require post service chemical cleaning to remove accumulated oxides at intervals of 15 - 35 kh. The need to clean will be based on an assessment of such factors as the development of flow imbalances through parallel tubes induced by the formation of rough oxide surfaces, an increasing risk of localised corrosion as the growth of porous oxides proceeds and the risk of tube blockage caused by the exfoliation of steam-grown oxides. The study has shown what heterogeneous multilayer oxides possessing a range of physical and chemical properties form on the alloy steels. They include porous and compact magnetites, chromium spinels and sesquioxide. Ammoniated citric acid has been shown to remove deposited and water-grown magnetites from the carbon and alloy steels but will not necessarily remove the substituted spinels grown on the alloy steels or the potentially spalling steam-grown magnetite on the A1SI 316 superheater. Citric acid supplemented with the reducing agent glyoxal completely removes all oxides from the boiler except the protective inner spinel formed on the 316. Removal of the spinels and compact magnetites occurs more by undercutting and physical detachment than by the dissolution. (author)

Chemical cleaning of Dresden Unit 1: Final report

International Nuclear Information System (INIS)

1986-05-01

The introduction of NS-1 solvent into the full primary system of Dresden Unit-1 nuclear power reactor on September 12, 1984, represented the culmination of several years of development, testing, planning, and construction. The requirement was to dissolve the highly radioactive deposits of primarily nickel ferrite without any corrosion which might compromise the reactor systems. During the actual cleaning with the NS-1 solvent, the chemical condition of the circulating solvent was measured. Iron, nickel, and radioactive cobalt all dissolved smoothly. The amount of copper in solution decreased in concentration, verifying expectations that metallic copper would plate on to clean metal surfaces. A special rinse formulation was employed after the primary cleaning steps and the ''lost'' copper was thus redissolved and removed from the system. After the cleaning was complete and the reactor had been refilled with pure water, radiation levels were measured. The most accurate of these measurements gave decontamination factors ranging well above 100, which indicated a significant removal of the radioactive deposits, and demonstrated the success of this project. Treatment of the radioactive liquid wastes from this operation required volume reduction and water purification. The primary method of processing the spent cleaning solvent and rinse water was evaporation. The resulting concentrate has been stored as a liquid, awaiting solidification to allow burial at a designated site. Water which was separated during evaporation, along with the dilute rinses, was processed by various chemical means, reevaporated, treated with activated carbon, and/or demineralized before its radionuclide and chemical content was low enough to allow it to be returned to Dresden Station for treatment or disposal. 60 figs., 31 tabs

OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F

Energy Technology Data Exchange (ETDEWEB)

Poirier, M.; Fink, S.

2011-07-22

The Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRR personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 6F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate. Some conclusions from this work are: (1) Approximately 65% of the oxalate added as oxalic acid was removed with the decanted liquid. (2) Approximately 1% of the oxalate (added to the tank as oxalic acid) formed precipitates with compounds such as nickel, manganese, sodium, and iron (II), and was dissolved with nitric acid. (3) As much as 30% of the oxalate may have decomposed forming carbon dioxide. The balance does not fully account for all the oxalate added. The offset represents the combined uncertainty in the analyses and sampling.

Chemical Agents: Personal Cleaning and Disposal of Contaminated Clothing

Science.gov (United States)

... What CDC is Doing Blog: Public Health Matters Chemical Agents: Facts About Personal Cleaning and Disposal of ... on Facebook Tweet Share Compartir Some kinds of chemical accidents or attacks may cause you to come ...

ALTERNATIVE AND ENHANCED CHEMICAL CLEANING: BASIC STUDIES RESULTS FY2010

Energy Technology Data Exchange (ETDEWEB)

King, W.; Hay, M.

2011-01-24

In an effort to develop and optimize chemical cleaning methods for the removal of sludge heels from High Level Waste tanks, solubility tests have been conducted using nonradioactive, pure metal phases. The metal phases studied included the aluminum phase gibbsite and the iron phases hematite, maghemite, goethite, lepidocrocite, magnetite, and wustite. Many of these mineral phases have been identified in radioactive, High Level Waste sludge at the Savannah River and Hanford Sites. Acids evaluated for dissolution included oxalic, nitric, and sulfuric acids and a variety of other complexing organic acids. The results of the solubility tests indicate that mixtures of oxalic acid with either nitric or sulfuric acid are the most effective cleaning solutions for the dissolution of the primary metal phases in sludge waste. Based on the results, optimized conditions for hematite dissolution in oxalic acid were selected using nitric or sulfuric acid as a supplemental proton source. Electrochemical corrosion studies were also conducted (reported separately; Wiersma, 2010) with oxalic/mineral acid mixtures to evaluate the effects of these solutions on waste tank integrity. The following specific conclusions can be drawn from the test results: (1) Oxalic acid was shown to be superior to all of the other organic acids evaluated in promoting the dissolution of the primary sludge phases. (2) All iron phases showed similar solubility trends in oxalic acid versus pH, with hematite exhibiting the lowest solubility and the slowest dissolution. (3) Greater than 90% hematite dissolution occurred in oxalic/nitric acid mixtures within one week for two hematite sources and within three weeks for a third hematite sample with a larger average particle size. This dissolution rate appears acceptable for waste tank cleaning applications. (4) Stoichiometric dissolution of iron phases in oxalic acid (based on the oxalate concentration) and the formation of the preferred 1:1 Fe to oxalate complex

Chemical cleaning as an essential part of steam generator asset management

International Nuclear Information System (INIS)

Stiepani, C.; Ammann, F.; Jones, D.; Evans, S.; Harper, K.

2010-01-01

Accumulation of deposits is intrinsic for the operation of Steam Generators in PWRs. Such depositions often lead to reduction of thermal performance, loss of component integrity and, in some cases to power restrictions. Accordingly removal of such deposits is an essential part of the asset management of the Steam Generators in a Nuclear Power Plant. Every plant has its individual condition, history and constraints which need to be considered when planning and performing a chemical cleaning. Typical points are: Sludge load amount and constitution of the deposits; Sludge distribution in the steam generator; Existing or expected corrosion problems; Amount and treatment possibilities for the waste generated. Depending on these points the strategy for chemical cleaning shall be evolved. The range of treatment starts with very soft cleanings with a removal of approx 100 kg per steam generator and goes to a full scale cleaning which can remove up to several thousand kilograms of deposits from a steam generator. Depending on the goal to be achieved and the steam generator present an adequate cleaning method shall be selected. Flexible and 'customizable' cleaning methods that can be adapted to the individual needs of a plant are therefore a must. Particular for the application of preventive cleanings where repeated or even regular application are intended, special focus has to be put on low corrosion and easy waste handling. Therefore AREVA has developed the 'C3' concept, Customized Chemical Cleaning concept. This concept covers the entire range of steam generator cleaning. Particular for the preventive maintenance cleanings processes with extreme low corrosion rates and easy waste handling are provided which make repeated applications safe and cost efficient. (author)

PWR steam generator chemical cleaning. Phase I: solvent and process development. Volume II

International Nuclear Information System (INIS)

Larrick, A.P.; Paasch, R.A.; Hall, T.M.; Schneidmiller, D.

1979-01-01

A program to demonstrate chemical cleaning methods for removing magnetite corrosion products from the annuli between steam generator tubes and the tube support plates in vertical U-tube steam generators is described. These corrosion products have caused steam generator tube ''denting'' and in some cases have caused tube failures and support plate cracking in several PWR generating plants. Laboratory studies were performed to develop a chemical cleaning solvent and application process for demonstration cleaning of the Indian Point Unit 2 steam generators. The chemical cleaning solvent and application process were successfully pilot-tested by cleaning the secondary side of one of the Indian Point Unit 1 steam generators. Although the Indian Point Unit 1 steam generators do not have a tube denting problem, the pilot test provided for testing of the solvent and process using much of the same equipment and facilities that would be used for the Indian Point Unit 2 demonstration cleaning. The chemical solvent selected for the pilot test was an inhibited 3% citric acid-3% ascorbic acid solution. The application process, injection into the steam generator through the boiler blowdown system and agitation by nitrogen sparging, was tested in a nuclear environment and with corrosion products formed during years of steam generator operation at power. The test demonstrated that the magnetite corrosion products in simulated tube-to-tube support plate annuli can be removed by chemical cleaning; that corrosion resulting from the cleaning is not excessive; and that steam generator cleaning can be accomplished with acceptable levels of radiation exposure to personnel

Steam generators secondary side chemical cleaning at Point Lepreau using the Siemen's high temperature process

International Nuclear Information System (INIS)

Verma, K.; MacNeil, C.; Odar, S.

1996-01-01

The secondary sides of all four steam generators at the Point Lepreau Nuclear Generating Stations were cleaned during the 1995 annual outage run-down using the Siemens high temperature chemical cleaning process. Traditionally all secondary side chemical cleaning exercises in CANDU as well as the other nuclear power stations in North America have been conducted using a process developed in conjunction with the Electric Power Research Institute (EPRI). The Siemens high temperature process was applied for the first time in North America at the Point Lepreau Nuclear Generating Station (PLGS). The paper discusses experiences related to the pre and post award chemical cleaning activities, chemical cleaning application, post cleaning inspection results and waste handling activities. (author)

Chemical cleaning of the Bruce A steam generators

International Nuclear Information System (INIS)

Le Surf, J.E.; Mason, J.B.; Symmons, W.R.; Yee, F.

1992-01-01

Deposits consisting mostly of oxides and salts and copper metal in the secondary side of the steam generators at the Bruce A Nuclear Generating Station have caused instability in the steam flow and loss of heat capacity, resulting in derating of the units and reduction in power production. Attempts to remove the deposits by pressure pulsing were unsuccessful. Water lancing succeeded in restoring stability, but restrictions on access prevented complete lancing of the tube support plate holes. Chemical cleaning using a modified EPRI-SGOG process has been selected as the best method of removing the deposits. A complete chemical cleaning system has been designed and fabricated for Ontario Hydro by Pacific Nuclear, with support from AECL CANDU and their suppliers. The system consists of self contained modules which are easily interconnected on site. The whole process is controlled from the Control Module, where all parameters are monitored on a computer video screen. The operator can control motorized valves, pumps and heaters from the computer key board. This system incorporates all the advanced technologies and design features that have been developed by Pacific Nuclear in the design, fabrication and operation of many systems for chemical decontamination and cleaning of nuclear systems. 2 figs

Evaluation of boiler chemical cleaning techniques

International Nuclear Information System (INIS)

1993-04-01

The EPRI/SGOG process, which has been selected by Ontario Hydro for use at the Bruce A station, is described. This process consists of alternating iron removal and copper removal steps, the two metals which comprise the bulk of the deposit in the Bruce A SGs. The iron removal solvent consists of ethylenediameinetetraacetic acid (EDTA), hydrazine, ammonium hydroxide and a proprietary corrosion inhibitor CCI-801. The copper removal solvent consists of EDTA, ethylene diamine and hydrogen peroxide. Ontario Hydro proposes to clean a bank of four SGs in parallel employing a total of six copper removal steps and four iron removal steps. Cleaning all eight SGs in a single Bruce A unit will generate 2,200 m 3 of liquid waste which will be treated by a wet air oxidation process. The iron and copper sludges will be buried in a landfill site while the liquid waste will be further treated by the Bruce sewage treatment plant. Some ammonia vapour will be generated through the wet air oxidation process and will be vented through a stack on top of the high bay of the spent solvent treatment plant. With the exception of the proprietary corrosion inhibitor, all chemicals that will be employed in the cleaning and waste treatment operations are standard industrial chemicals which are well characterized. No extraordinary hazards are anticipated with their use as long as adequate safety precautions are taken

CHEMICAL CLEANING OF NANOFILTRATION MEMBRANES FOULED BY ORGANIC MATTERS

Directory of Open Access Journals (Sweden)

CHARLENE C. H. KOO

2016-07-01

Full Text Available Membrane fouling is a term to describe non-integral substance on membrane surface which results in rapid decline of permeation flux and deteriorate the performance of membrane. Chemical cleaning agents especially like alkaline cleaners are most widely employed to restore the membrane performance. This research mainly investigated the potential use of sodium hydroxide (NaOH and sodium hypochlorite (NaOCl as the chemical cleaning agents to restore the permeate flux of organically fouled nanofiltration (NF membranes under varying applied pressure and flow condition. The performances of the cleaning protocols were quantified using flux recovery and resistance removal. The results demonstrated that NaOCl is more effective than NaOH. This observation is also in line with FTIR analysis in which the transmittance intensity showed by FTIR spectra of NaOCl is higher than that of NaOH. The results also reported that higher flux recovery and resistance removal were achieved when the fouled NF membranes were cleaned with higher concentration of chemical agents and applied pressure. However, the improvements of flux recovery and resistance removal by increasing the applied pressure were found insignificant at higher applied pressure range (16 to 18 bar than the lower applied pressure range (i.e. 12 to 14 bar. This research plays an important role by identifying the key parameters that could restore the flux of organically fouled NF membranes significantly.

Chemical cleaning's role in tube failure prevention and correction

International Nuclear Information System (INIS)

Shields, K.J.; Dooley, R.B.

2002-01-01

Properly applied, chemical cleaning is a valuable tool used to prevent tube failures involving overheating and corrosion due to waterside deposits. In many cases, however, cleaning becomes yet an additional cost associated with correction of tube failure incidents. Discussion is focused on approaches taken to appraise tube waterside cleanliness and determine the need to clean, as typically practiced in conventional fossil plants. Also presented is an assessment of the suitability and limitations of these approaches to plants with heat recovery steam generator (HRSG) units. (orig.)

Corrosion Behavior of SA508 Coupled with and without Magnetite in Chemical Cleaning Environments

International Nuclear Information System (INIS)

Son, Yeong-Ho; Jeon, Soon-Hyeok; Song, Geun Dong; Hur, Do Haeng; Lee, Jong-Hyeon

2017-01-01

To mitigate these problems, chemical cleaning process has been widely used. However, the chemical cleaning solution can affect the corrosion of SG structural materials as well as the magnetite dissolution. During the chemical cleaning process, the galvanic corrosion between SG materials and magnetite is also anticipated because they are in electrical connection. However, the corrosion measurement or monitoring for the materials has been performed without consideration of galvanic effect coupled with magnetite during the chemical cleaning process. In this study, the effect of temperature and EDTA concentration on the corrosion behavior of SA508 tubesheet material with and without magnetite was studied in chemical cleaning solutions. The galvanic corrosion behavior between SA508 and magnetite is predicted by using the mixed potential theory and its effect on the corrosion rate of SA508 is also discussed. By newly designed immersion test, it was confirmed that the extent of galvanic corrosion effect between SA508 and magnetite increased with increasing temperature and EDTA concentration. The galvanic corrosion behavior of SA508 coupled with magnetite in chemical cleaning environments was predicted by the mixed potential theory and verified by ZRA and LP technique. Galvanic coupling increased the corrosion rate of SA508 due to the shift in its potential to the anodic direction. Therefore, the galvanic corrosion effect between SA508 and magnetite should be considered when the corrosion measurement is performed during the chemical cleaning process in steam generators.

Qualification test of chemical cleaning for secondary side of steam generator in Qinshan Nuclear Power Plant

International Nuclear Information System (INIS)

Zhang Mengqin; Zhang Shufeng; Yu Jinghua; Hou Shufeng

1997-07-01

The chemical cleaning technique for removing sludge on the secondary side in Qinshan Nuclear Power Plant has been qualified. The chemical cleaning process will carry out during shutdown refuelling. The qualification test has studied the effect of chemical cleaning agent component, cleaning time on dissolution effectiveness of sludge (Fe 3 O 4 ) and to evaluate corrosion situation of main materials of SG in the cleaning process. The main component of cleaning agent is EDTA. The cleaning temperature is 20∼30 degree C. It is determined that allowable remains amount of cleaning agent (EDTA). The technique of cleaning, rinse, passivation for the chemical cleaning in Qinshan Nuclear Power Plant has been made. The qualification test shown that the technique can dissolve Fe 3 O 4 >1 g/L, the corrosion of materials is in allowable value, the allowable remains of EDTA is <0.01%. The technique character is static, ambient temperature. (9 refs., 12 tabs.)

Alternative Chemical Cleaning Methods for High Level Waste Tanks: Simulant Studies

Energy Technology Data Exchange (ETDEWEB)

Rudisill, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); King, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hay, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jones, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-11-19

Solubility testing with simulated High Level Waste tank heel solids has been conducted in order to evaluate two alternative chemical cleaning technologies for the dissolution of sludge residuals remaining in the tanks after the exhaustion of mechanical cleaning and sludge washing efforts. Tests were conducted with non-radioactive pure phase metal reagents, binary mixtures of reagents, and a Savannah River Site PUREX heel simulant to determine the effectiveness of an optimized, dilute oxalic/nitric acid cleaning reagent and pure, dilute nitric acid toward dissolving the bulk non-radioactive waste components. A focus of this testing was on minimization of oxalic acid additions during tank cleaning. For comparison purposes, separate samples were also contacted with pure, concentrated oxalic acid which is the current baseline chemical cleaning reagent. In a separate study, solubility tests were conducted with radioactive tank heel simulants using acidic and caustic permanganate-based methods focused on the “targeted” dissolution of actinide species known to be drivers for Savannah River Site tank closure Performance Assessments. Permanganate-based cleaning methods were evaluated prior to and after oxalic acid contact.

Steam Generator Chemical Cleaning Application: Korean Experience in PWR NPP

International Nuclear Information System (INIS)

Hwang, In-Ho; Varrin-Jr, Robert-D.; Little, Michael-J.; Oh, Yeon-Ok; Choo, Seong-Jib; Park, Jin-Hyeok

2012-09-01

Korea Hydro and Nuclear Power (KHNP) performed an EPRI/SGOG chemical cleaning of the secondary side of the steam generators at Ulchin Unit 3 (UCN3) in March 2011 and at Ulchin Unit 4 (UCN4) in September 2011. The steam generator chemical cleaning (SGCC) was performed with venting at the top-of-tube sheet (TTS) and at tube support plates (TSPs) 4, 5, 6, 7, 8, 9, and 10. A primary objective of this SGCC was to address outer diameter stress corrosion cracking (ODSCC), which has been observed at the TTS and TSPs in the UCN3 SGs. The EPRI/SGOG process has been shown to effectively reduce prevailing ODSCC rates at the TTS and TSPs, particularly when applied with periodic venting in this application. This was the first full-length SGCC campaign with venting performed in Korea. Ulchin Unit 3 commenced commercial operation in August 1998 and Ulchin Unit 4 commenced commercial operation in December 1999. UCN3 and UCN4 are a two-loop pressurized water reactor (PWR) of the Korea Standard Nuclear Plant (KSNP) design. The SGs contain high-temperature mill annealed (HTMA) Alloy 600 tubing and are similar in design to the Combustion Engineering CE-80. The KSNP SGs have been susceptible to outer diameter stress corrosion cracking (ODSCC), which is consistent with operating experience for other SGs containing Alloy 600HTMA tubing material. The UCN3/4 SGs have recently begun to experience ODSCC. Hankook Jungsoo Industries Co., Ltd (HaJI) was selected as the cleaning vendor by KHNP. To date, HaJI has completed five Advanced Scale Conditioning Agent (ASCA) cleaning applications and two EPRI/SGOG Steam Generator Chemical Cleaning (SGCC) campaigns for KHNP. The goal of total deposit removal of the applications were successfully achieved and the amounts are 3,579 kg at UCN3 and 3,786 kg at UCN4 which values were estimated before each cleaning by analysing ECT signal and liquid samples from the SGs. The deposits from the SGs were primarily composed of magnetite. There were no chemical

Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

KAUST Repository

Li, Zhenyu

2017-07-27

Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after cleaning with NaOCl and Alconox. Changes in the membrane structure and increased hydrophilicity in the surrounding areas of the aquaporin may be accountable for the increase in water permeability. The membrane shows stable salt rejection up to 99% after all cleaning agents were tested. A 15-day experiment with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane exhibits chemical resistance for most agents used in membrane cleaning procedures, maintaining a stable flux and high salt rejection.

Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

KAUST Repository

Li, Zhenyu; Valladares Linares, Rodrigo; Bucs, Szilard; Fortunato, Luca; Hé lix-Nielsen, Claus; Vrouwenvelder, Johannes S.; Ghaffour, NorEddine; Leiknes, TorOve; Amy, Gary

2017-01-01

Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after cleaning with NaOCl and Alconox. Changes in the membrane structure and increased hydrophilicity in the surrounding areas of the aquaporin may be accountable for the increase in water permeability. The membrane shows stable salt rejection up to 99% after all cleaning agents were tested. A 15-day experiment with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane exhibits chemical resistance for most agents used in membrane cleaning procedures, maintaining a stable flux and high salt rejection.

Steam generator chemical cleaning demonstration test No. 1 in a pot boiler

International Nuclear Information System (INIS)

Key, G.L.; Helyer, M.H.

1981-04-01

The effectiveness of the Electric Power Research Institute (EPRI Mark I) chemical cleaning solvent process was tested utilizing a 12 tube pot boiler that had previously been fouled and dented under 30 days of high chloride fault chemistry operation. Specifically, the intent of this chemical cleaning test was to: (1) dissolve sludge from the tubesheet, (2) remove non-protective magnetite from dented tube/support crevice regions, and (3) quantify the extent of corrosion of steam generator material during the test. Two laboratory cleaning demonstrations of 191 and 142 hours were performed

Development of clean chemical mechanical polishing systems; Clean CMP system

Energy Technology Data Exchange (ETDEWEB)

Tsujimura, M.; Hosokawa, M. [Ebara Corp., Tokyo (Japan)

1998-10-20

Described herein are clean chemical mechanical polishing (CMP) systems developed by Ebara. A CMP system needs advanced peripheral techniques, in addition to those for grinding adopted by the conventional system, in order to fully exhibit its inherent functions. An integrated design concept is essential for the CMP steps, including slurry supplying, polishing, washing, process controlling and waste fluid treatment. The Ebara has adopted a standard concept `Clean CMP, dry-in and dry-out of wafers,` and provided world`s highest grades of techniques for inter-layer insulating film, shallow trench isolation, plug and wiring. The head for the polishing module is specially designed by FEM, to improve homogeneity of wafers from the center to edges. The dresser is also specially designed, to improve pad surface topolody after dressing. A slurry dipsersing method is developed to reduce slurry consumption. Various washing modules, designed to have the same external shape, can be allocated to various functions. 10 figs.

Chemical-Cleaning Demonstration Test No. 2 in a mock-up steam generator

International Nuclear Information System (INIS)

Jevec, J.M.; Leedy, W.S.

1983-04-01

This report describes the results of the mockup demonstration test of the first modified baseline process under Contract S-127, Chemical Cleaning of Nuclear Steam Generators. The objective of this program is to determine the feasibility of cleaning the secondary side of nuclear steam generators with state-of-the-art chemical cleaning technology. The first step was to benchmark a baseline process. This process was then modified to attempt to eliminate the causes of unacceptable cleaning performance. The modified baseline process consists of an EDTA/H 2 O 2 -based copper solvent and a near-neutral, EDTA/N 2 H 4 -based magnetite and crevice solvent. This report also presents the results of three inhibitor evaluation mockup runs used in the evaluation of the modified baseline process

Study of chemical cleaning technique for removing sludge in secondary side of PWR SG

International Nuclear Information System (INIS)

Zhang Mengqin; Zhang Shufeng; Pan Qingchun; Yu Jinghua; Hou Shufeng

1993-12-01

The effect of components, concentration, pH, temperature, cleaning time and flowrate of chemical cleaning solvent made from EDTA mainly on Fe 3 O 4 solubility and corrosion rate of A3 carbon steel, S271 low alloy steel and 800 alloy are introduced. A small chemical cleaning test loop (30L) was built to study the cleaning technique. The effect of residue of chemical cleaning solvent on anti-corrosion performance of materials has been studied under the simulation condition of PWR (pressure water reactor) SG (steam generator) secondary side. The results show that the chemical solvent (pH = 7, 10% EDTA, 1% assistance solvent and 0.25% inhibitor A) can dissolve Fe 3 O 4 18 ∼23 g/L under the conditions of 93 +- 5 degree C, 8 hours and 112 r/min (1.8 ∼ 2.0 t/h). The corrosion rate of material is low. When the residue of EDTA is less than 0.01% there is no impact on the anti-corrosion performance of materials in PWR SG secondary side at normal operation condition (260 +- 5 degree C)

Method of cleaning oil slicks and chemical spills

International Nuclear Information System (INIS)

Billings, L.

1992-01-01

This patent describes a method of cleaning a floating chemical spill on a body of water. It comprises: providing a quantity of popular bark-based pelleted or granular product, flotation means and a flexible net having openings generally smaller than the smallest whole pellet dimension of the pelleted product, spreading the net over a chemical spill on the body of water, connecting the floatation means to the net thereby supporting the net adjacent the surface of the body of water, placing the poplar bark-based product on the net, absorbing the floating chemical spill into the product, and removing the chemical soaked product from the body of water

Tube micro-fouling, boiling and steam pressure after chemical cleaning

International Nuclear Information System (INIS)

Hu, M.H.

1998-01-01

This paper presents steam pressure trends after chemical cleaning of steam generator tubes at four plants. The paper also presents tube fouling factor that serves as an objective parameter to assess tubing boiling conditions for understanding the steam pressure trend. Available water chemistry data helps substantiate the concept of tube micro-fouling, its effect on tubing boiling, and its impact on steam pressure. All four plants experienced a first mode of decreasing steam pressure in the post-cleaning operation. After 3 to 4 months of operation, the decreasing trend stopped for three plants and then restored to a pre-cleaning value or better. The fourth plant is soil in decreasing trend after 12 months of operation. Dissolved chemicals, such as silica, titanium can precipitate on tube surface. The precipitate micro-fouling can deactivate or eliminate boiling nucleation sites. Therefore, the first phase of the post-cleaning operation suffered a decrease in steam pressure or an increase in fouling factor. It appears that micro fouling by magnetite deposit can activate or create more bubble nucleation sites. Therefore, the magnetite deposit micro-fouling results in a decrease in fouling factor, and a recovery in steam pressure. Fully understanding the boiling characteristics of the tubing at brand new, fouled and cleaned conditions requires further study of tubing surface conditions. Such study should include boiling heat transfer tests and scanning electronic microscope examination. (author)

Tank 12H Acidic Chemical Cleaning Sample Analysis And Material Balance

International Nuclear Information System (INIS)

Martino, C. J.; Reboul, S. H.; Wiersma, B. J.; Coleman, C. J.

2013-01-01

A process of Bulk Oxalic Acid (BOA) chemical cleaning was performed for Tank 12H during June and July of 2013 to remove all or a portion of the approximately 4400 gallon sludge heel. Three strikes of oxalic acid (nominally 4 wt % or 2 wt %) were used at 55 deg C and tank volumes of 96- to 140-thousand gallons. This report details the sample analysis of a scrape sample taken prior to BOA cleaning and dip samples taken during BOA cleaning. It also documents a rudimentary material balance for the Tank 12H cleaning results

The impact of chemical cleaning on separation efficiency and properties of reverse osmosis membrane

KAUST Repository

Baatiyyah, Hani

2018-04-01

One of most major concerns from both cost-effective and technical point of view in membrane process industry is membrane cleaning. The aim of the project was to investigate the variations in membrane surface properties and separation efficiency of reverse osmosis membrane. Compativtive analysis have to be performed on four RO membrane before and after exposing the virgin membrane into chemical cleaning to identify and analysis the impact of the chemical cleaning on the performance of RO membrane. Commerical chemical cleaning used in this project were caustic and acidic cleaning agent. The project’s aim is the investigation of simulation software’s precision for the four membranes performance projection at different conditions of the feed water. The assessment of the membranes performance was done in the Innovation Cluster at pilot plant that was industrial in size. The main commercial elements used were the thin-film composite membranes with a spiral-wound of 8-inch polyamide. Ultrafiltration (UF) and seawater RO membrane pretreatment process was done for the red sea sourced feed water. A pressure vessel dimensioned at 8-inch was operated in conjunction with an individual element at 8 -20 m3/hr feed flow rate, with an 8 to 12 % recovery and an average 35,000-42,000 mg/L of total dissolved solids (TDS) composition for the feed water. To achieve the project’s aim in assessing the membranes, three phase experimental stages were completed. The membranes performance was assessed in terms of their water flux, salt rejection, boron rejection, bicarbonate rejection and permeate quality. In addition, the membrane surfaces were characterized after exposing the fresh membranes with a chemical cleaning reagent. The experimental results showed an increase in both permeate flow and salt passage for all studied elements. The changes in the membranes performance were systematically explained based on the changes in the charge density and chemical structure of the membranes

PWR steam generator chemical cleaning. Phase I: Final report, Volume I

International Nuclear Information System (INIS)

1978-07-01

Two chemical cleaning solvent systems and two application methods were developed to remove the sludge in nuclear steam generators and to remove the corrosion products in the annuli between the steam generator tubes and the support plates. Laboratory testing plus subsequent pilot testing has demonstrated that, in a reasonable length of time, both solvents are capable of dissolving significant amounts of sludge, and of dissolving tightly packed magnetite in tube/support plate crevices. Further, tests have demonstrated that surface losses of the materials of construction in steam generators can be controlled to acceptable limits for the duration of the required cleaning period. Areas requiring further study and test have been identified, and a preliminary procedure for chemical cleaning nuclear steam generators has been chosen subject to quantification based on additional tests prior to actual in-plant demonstration

Disposal and handling of nuclear steam generator chemical cleaning wastes

International Nuclear Information System (INIS)

Larrick, A.P.; Schneidmiller, D.

1978-01-01

A large number of pressurized water nuclear reactor electrical generating plants have experienced a corrosion-related problem with their steam generators known as denting. Denting is a mechanical deformation of the steam generator tubes that occurs at the tube support plates. Corrosion of the tube support plates occurs within the annuli through which the tubes pass and the resulting corrosion oxides, which are larger in volume than the original metal, compress and deform the tubes. In some cases, the induced stresses have been severe enough to cause tube and/or support cracking. The problem was so severe at the Turkey Point and Surrey plants that the tubing is being replaced. For less severe cases, chemical cleaning of the oxides, and other materials which deposit in the annuli from the water, is being considered. A Department of Energy-sponsored program was conducted by Consolidated Edison Co. of New York which identified several suitable cleaning solvents and led to in-plant chemical cleaning pilot demonstrations in the Indian Point Unit 1 steam generators. Current programs to improve the technology are being conducted by the Electric Power Research Institute, and the three PWR NSSS vendors with the assistance of numerous consultants, vendors, and laboratories. These programs are expected to result in more effective, less corrosive solvents. However, after a chemical cleaning is conducted, a large problem still remains- that of disposing of the spent wastes. The paper summarizes some of the methods currently available for handling and disposal of the wastes

The AREVA customized chemical cleaning C3-concept as part of the steam generator asset management

International Nuclear Information System (INIS)

Weiss, Steffen; Drexler, Andreas

2012-09-01

In pressurized water reactors corrosion products and impurities are transported into the steam generators by feed water. Corrosion products and impurities are accumulated in the SGs as deposits and scales on the tubes, the tube support structures and the tube sheet. Depending on the location, the composition and the morphology such deposits may negatively affect the performance of the steam generators by reducing the thermal performance, changing the flow patterns and producing localized corrosion promoting conditions. Accordingly removal of deposits or deposit minimization strategies are an essential part of the asset management program of the steam generators in Nuclear Power Plants. It is evident that such a program is plant specific, depending on the individual condition prevailing. Parameters to be considered are for example: - Steam generator and balance of plant design; - Secondary side water chemistry treatment; - Deposit amount and constitution; - Deposit distribution in the steam generator; - Existing or expected corrosion problems. After evaluation of the steam generator condition a strategy for deposit minimization has to be developed. Depending on the individual situation such strategies may span from curative full scale cleanings which are capable of removing the entire sludge inventory in the range of several 1000 kg per SG to preventive cleanings that remove only a portion of the deposits in the range of several 100 kg per SG. But also other goals depending on the specific plant situation, like tube sheet sludge piles or hard scale removal, may be considered. Beside the chemical cleaning process itself also the integration of the process into the outage schedule and considerations about its impact on other maintenance activities is of great importance. It is obvious that all these requirements cannot be met easily by a standardized cleaning method, thus a customisable chemical cleaning technology is required. Based on its comprehensive experience

Benefits of integrating chemical and mechanical cleaning processes for steam generator sludge removal

International Nuclear Information System (INIS)

Varrin, R.D.; Ferriter, A.M.; Oliver, T.W.; Le Surf, J.E.

1992-01-01

This paper discusses the benefits of performing in-bundle tubesheet lancing in conjunction with chemical cleaning of PWR and PHWR steam generators in which a hard sludge pile is known to exist. The primary benefits of in-bundle lancing are to: (1) increase the exposed area of the sludge pile by cutting furrows in the surface thereby enhancing dissolution of sludge, (2) reduce the volume of solvents required since material removed by lancing does not have to be dissolved chemically, (3) improve rinsing and removal of residual solvent between iron and copper dissolution steps, and (4) allow for verification of process effectiveness by providing high quality in-bundle visual inspection. The reduction in solvent volumes can lead to a significant reduction in solvent costs and waste processing. A case study which includes an economic evaluation for a combined chemical and mechanical cleaning shows a potential cost saving of up to US$ 300,000 over use of chemical cleaning alone. 14 refs., 2 tabs., 2 figs

Steam generator secondary side chemical cleaning at Gentilly-2

International Nuclear Information System (INIS)

Plante, S.

2006-01-01

After more than 20 years of operation, the secondary side of the four steam generators at Gentilly-2 were chemically cleaned during the 2005 annual outage. The FRAMATOME ANP high temperature cleaning process used to remove magnetite loading involved stepwise injection of solvent with PHT temperature in the range 160 o C to 175 o C. The heat required to maintain the PHT temperature was provided by the operation of the main PHT pumps and the reactor core residual heat. The temperature control was accomplished by the shutdown cooling system heat exchangers. A total of 1280 kg of magnetite was removed from the four steam generators. A copper-cleaning step was applied after the iron step. The PHT has been cooled down and the steam generators drained to temporary tanks and dried in preparation of the copper step. The process has been applied at room temperature, two boilers at a time. The solvent removed a total of 116 kg of copper. During the iron step, steam flow to the feedwater tank chemically contaminate the Balance Of Plant (BOP) systems. The isolation of this path should have been part of the G2 procedures. Around 700 m3 of water had to be drained to interim storage tanks for subsequent resin treatment before disposal. Visual inspection of BO1 tubesheet and first support plate showed clean surfaces without measurable sludge pile. Upper support plates visual inspection of BO4 revealed that broach holes blockage reported in 2000 is still present in peripheral area. Following the plant restart, the medium range level measurement instability observed since several years for BO3 was no more present. As anticipated, it also has been observed that the medium and wide range level measurements have shifted down as a result of downcomer flow increase after the cleaning. The cleaning objectives were achieved regarding the fouling reduction on the steam generators secondary side but broach holes blockage of the upper support plate is still present in periphery. (author)

Annual Report, Fall 2016: Alternative Chemical Cleaning of Radioactive High Level Waste Tanks - Corrosion Test Results

International Nuclear Information System (INIS)

Wyrwas, R. B.

2016-01-01

The testing presented in this report is in support of the investigation of the Alternative Chemical Cleaning program to aid in developing strategies and technologies to chemically clean radioactive High Level Waste tanks prior to tank closure. The data and conclusions presented here were the examination of the corrosion rates of A285 carbon steel and 304L stainless steel exposed to two proposed chemical cleaning solutions: acidic permanganate (0.18 M nitric acid and 0.05M sodium permanganate) and caustic permanganate. (10 M sodium hydroxide and 0.05M sodium permanganate). These solutions have been proposed as a chemical cleaning solution for the retrieval of actinides in the sludge in the waste tanks, and were tested with both HM and PUREX sludge simulants at a 20:1 ratio.

Annual Report, Fall 2016: Alternative Chemical Cleaning of Radioactive High Level Waste Tanks - Corrosion Test Results

Energy Technology Data Exchange (ETDEWEB)

Wyrwas, R. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-09-01

The testing presented in this report is in support of the investigation of the Alternative Chemical Cleaning program to aid in developing strategies and technologies to chemically clean radioactive High Level Waste tanks prior to tank closure. The data and conclusions presented here were the examination of the corrosion rates of A285 carbon steel and 304L stainless steel exposed to two proposed chemical cleaning solutions: acidic permanganate (0.18 M nitric acid and 0.05M sodium permanganate) and caustic permanganate. (10 M sodium hydroxide and 0.05M sodium permanganate). These solutions have been proposed as a chemical cleaning solution for the retrieval of actinides in the sludge in the waste tanks, and were tested with both HM and PUREX sludge simulants at a 20:1 ratio.

Carbon steel corrosion prevention during chemical cleaning of steam generator secondary side components

International Nuclear Information System (INIS)

Fulger, M.; Lucan, D.; Velciu, L.

2009-01-01

During operation of a nuclear power plant, many contaminants, such as solid particles or dissolved species are formed in the secondary circuit, go into steam generator and deposit as scales on heat transfer tubing, support plate or as sludge on tube sheet. By accumulation of these impurities, heat transfer is reduced and the integrity of the steam generator tubing is influenced. Chemical cleaning is a qualified, efficient measure to improve steam generator corrosion performance. The corrosion mechanism can be counteracted by the chemical cleaning of the deposits on the tube sheet and the scales on the heat transfer tubing. The major component of the scales is magnetite, which can be dissolved using an organic chelating agent (ethylenediaminetetraacetic acid, EDTA) in combination with a complexing agent such as citric acid in an alkaline reducing environment. As the secondary side of SG is a conglomerate of alloys it is necessary to choose an optimal chemical cleaning solution for an efficient cleaning properties and at the same time with capability of corrosion prevention of carbon steel components during the process. The paper presents laboratory tests initiated to confirm the ability of this process to clean the SG components. The experiments followed two paths: - first, carbon steel samples have been autoclavized in specific secondary circuit solutions of steam generator to simulate the deposits constituted during operation of this equipment; - secondly, autoclavized samples have been cleaned with a solvent composed of EDTA citric acid, hydrazine of pH = 5 and temperature of 85 deg. C. Before chemical cleaning, the oxide films were characterized by surface analysis techniques including optical microscopy, scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Applied to dissolve corrosion products formed in a steam generator, the solvents based on chelating agents are aggressive toward carbon steels and corrosion inhibitors are

Influence of wet chemical cleaning on quantum efficiency of GaN photocathode

International Nuclear Information System (INIS)

Wang Xiao-Hui; Gao Pin; Wang Hong-Gang; Li Biao; Chang Ben-Kang

2013-01-01

GaN samples 1–3 are cleaned by a 2:2:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%) to de-ionized water; hydrochloric acid (37%); or a 4:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%). The samples are activated by Cs/O after the same annealing process. X-ray photoelectron spectroscopy after the different ways of wet chemical cleaning shows: sample 1 has the largest proportion of Ga, N, and O among the three samples, while its C content is the lowest. After activation the quantum efficiency curves show sample 1 has the best photocathode performance. We think the wet chemical cleaning method is a process which will mainly remove C contamination. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Development of chemical cleaning formulation for service water system of FBTR

International Nuclear Information System (INIS)

Velmurugan, S.; Narasimhan, S.V.; Das, P.C.; Mathur, P.K.

1995-01-01

Service water system of Fast Breeder Test Reactor (FBTR) was found to be corroded and at few locations, the corrosion product oxides were choking the smaller diameter pipelines. An attempt was made to develop a chemical cleaning formulation to chemically remove the oxides using a surface conditioner and chelating agents. Of the several complexants tested, hydroxyethylethylene diamine tetraacetic acid (HEDTA) was found to be better than other complexants from the point of view of oxide dissolution efficiency, solubility etc. A two stage chemical cleaning process involving conditioning of the oxide layer with 0.1% tannic acid followed by exposure of the conditioned oxide layer with a formulation containing 1% HEDTA + 0.5% Sodium Gluconate +0.2% hexamine was recommended to remove the corrosion product oxide present in the service water system. (author). 4 refs., 2 tabs

Chemical cleaning of steam generators: application to Nogent 1

International Nuclear Information System (INIS)

Fiquet, J.M.; Veysset, J.P.; Esteban, L.; Saurin, P.

1991-01-01

EDF has patented a chemical cleaning process for PWR steam generators, based on the use of a mixture or organic acids in order to dissolve iron oxides and copper with a single solution and clean dented crevices. Qualification tests have permitted to demonstrate effectiveness of the solution and its innocuousness related to steam generator materials. The process, the licence of which belongs to SOMAFER RA and Framatome has been implemented in France at Nogent. The goal was to dissolve iron oxides allowing metallic particles, aggregated on the tubesheet, to be released and mechanically removed. The effectiveness was satisfactory and this treatment is to be extended to other units. (author)

CHEMICAL AND ENERGETIC CONTENT OF CORN BEFORE AND AFTER PRE-CLEANING

Directory of Open Access Journals (Sweden)

Sandra Iara Furtado Costa Rodrigues

2015-04-01

Full Text Available The poultry industry normally has little control over the raw material that arrives at the processing plant. This experiment aimed to evaluate chemical and energetic quality of corn obtained in a feed mill before and after pre-cleaning. Twenty samples of 30 kg of corn each were taken from trucks delivering corn to the mill. The trucks were then unloaded and the material passed through a pre-cleaning process when another sample was taken. Samples were graded and physical properties evaluated: density (g/L, grain percentages of foreign material, impurities, fragments, broken, soft, insect damaged, fire-burnt, fermented, damaged, cracked and fine particles, as well as chemical composition analysis: Apparent metabolizable energy for poultry (AME, ether extract (EE, crude fiber (CF, starch (STA, water activity (WA, crude protein (CP, digestible and total lysine, methionine, cystine, threonine, tryptophan, valine, isoleucine, leucine, phenylalanine, histidine and arginine. The experiment was a randomized design with two treatments (before and after pre-cleaning and twenty replications. Data was analyzed using SAS ® and treatment differences obtained using F test. Correlations and principal components were calculated. There was a decrease in density after the pre-cleaning process, which was probably due to the removal of earth and stones rather than grain and its fractions. Significant increases were found for insect damage, fermented and damaged grain while fire-burn was significantly reduced after the pre-cleaning process. Starch increased after pre-cleaning which is a result of contaminants that normally are poor in this carbohydrate, but fiber levels increased too. Apparent metabolizable energy, aminoacids, digestible (P<0.05 and total (P<0.05 histidine, total lysine and methionine (P<0.1 levels were reduced after pre-cleaning. Density was higher when there were fewer impurities such as straw, husk or small grains. Broken corn was positively

Final status report in preparation for the chemical cleaning of Dresden-1, DNS-D1-034

International Nuclear Information System (INIS)

1981-09-01

This report discusses the status of all of the activities conducted in preparation for the chemical cleaning of the Dresden-1 Nuclear Power Plant of Commonwealth Edison of Illinois. The metallurgical testing of a solvent and its ability to remove radioactivity are reviewed. Included are all engineering details relating to the modifications to the primary system to be able to perform the chemical cleaning and to rinse the cleaning solvent out of the equipment. A facility to store and process spent cleaning solutions is described in detail. Construction activities and preoperational activities are recounted. Licensing activities, quality assurance, safety, and radiation protection are discussed. The report includes recommendations for future actions for restarting the project when approval is received. All of the efforts discussed in this Final Status Report led to the conclusion that the chemical cleaning, as planned, was feasible. All of the necessary modifications and new equipment are in place and are operational

Effectiveness of aged graffiti cleaning on granite by chemical and mechanical procedures

Science.gov (United States)

Gomes, Vera; Dionísio, Amélia; Santiago Pozo-Antonio, José

2017-04-01

Granite is one of the most common building stones in the European Cultural Heritage mainly in Northwest Iberian Peninsula. Nowadays, graffiti when a result of an act of vandalism is one of the most important threat, involving a serious risk to heritage sustainability. The cleaning is expensive and in most of the cases, the complete removal is not achieved. Many cities worldwide spend huge amounts of money in cleaning campaigns and European Commission started to create urban environment policies to prevent and eliminate graffiti and also finance projects to develop new cleaning procedures and antigraffiti coatings1,2. However, in many cases graffiti is applied in monuments and façades without antigraffiti and in real practice, they are only cleaned after being long exposure to the atmosphere, reaction with the environment (rain and atmospheric pollutants) and also with the substrate, leading changes in their physical and chemical properties. However, no scientific studies focused on graffiti aging were found and also on the influence of the aging on the cleaning effectiveness, which is always evaluated with fresh graffiti. Therefore, the need to optimize the cleaning of aged graffiti is urgent. This paper aims to study the influence of the exposition of graffiti paintings to one of the most important urban contaminant SO2 on the cleaning effectiveness of graffiti on the valuable ornamental granite Rosa Porriño. Two different chemical products and two different mechanical procedures based on low pressure projection (wet and dry) were evaluated. Four different colour graffiti paintings (red, black, blue and silver) with different compositions were tested. The criteria for assessing the global cleaning effectiveness was considering the graffiti extraction and also the damage induced on the substrate through changes in the chromatic parameters, static contact angle and surface roughness of the stones, identification of deleterious products and modification of the

PWR steam generator chemical cleaning. Phase II. Final report

International Nuclear Information System (INIS)

1980-01-01

Two techniques believed capable of chemically dissolving the corrosion products in the annuli between tubes and support plates were developed in laboratory work in Phase I of this project and were pilot tested in Indian Point Unit No. 1 steam generators. In Phase II, one of the techniques was shown to be inadequate on an actual sample taken from an Indian Point Unit No. 2 steam generator. The other technique was modified slightly, and it was demonstrated that the tube/support plate annulus could be chemically cleaned effectively

Basic environmental principles for the promotion of clean and efficient energy

International Nuclear Information System (INIS)

Hanmer, R.; Connor-Lajambe, H.

1994-01-01

The purpose of this paper is to reiterate what might be considered basic principles for promoting clean and efficient energy. These principles have very important implications for the design of energy supply and transportation facilities, but they go far beyond that to unify such design with the design, use and maintenance of many other types of facilities and goods. These principles also affect the way we consider energy security in the context of sustainable development. In annex, this paper presents the recommendation of the Council, with a list of environmentally favourable energy options. (TEC). 2 refs., Annex

Enhanced Chemical Cleaning: Effectiveness Of The UV Lamp To Decompose Oxalates

International Nuclear Information System (INIS)

Ketusky, E.; Huff, T.; Sudduth, C.

2010-01-01

Enhanced Chemical Cleaning is a new process scheduled to begin cleaning Savannah River Site High Level Waste Tanks in 2012. It is an improvement over the current chemical cleaning method, in that it minimizes downstream impacts on the High Level Waste System. It is based on a state of the art scale removal process used on the secondary side of nuclear power plants, with modifications to accommodate the unique constraints created by the tanks. Both Enhanced Chemical Cleaning and the scale removal process are founded on dissolving metal oxides/hydroxides using oxalic acid, with subsequent oxalate decomposition via hydroxylation using ozone or peroxide, and UV light as a catalyst. A divergence Enhanced Chemical Cleaning has from nuclear power scale removal is the significantly increased solids concentration during oxalate decomposition. These solids can limit the ability of the UV light to create hydroxyl radicals, either by limiting the ability of the light to penetrate through the solution, or by increasing the fouling rate on the UV light. Both will decrease the overall catalytic effectiveness, thereby decreasing the concentration of formed hydroxyl radicals. The hydroxyl radicals are the driving force behind the oxalate decomposition. To understand the impact of increased solids, testing was performed using a medium pressure UV light inside an ozone supplied Oxalate Decomposition Reactor. Using a dissolved metal sludge simulant with an initial oxalate concentration greater than 12,000 ppm, and an initial pH of about 2.0, the spent acid solution was recirculated through the reactor, while the UV light was allowed to foul. For the first few hours, the oxalate decomposition rate was about 1,300 ppm/hour. After about 3 hours, enough time for the UV lamp to foul, the oxalate decomposition rate decreased to about 500 ppm/hour. The decomposition rate then remained roughly constant for the next 16 hours. Overall, testing showed that the oxalate destruction rate decreased

Combustion behaviour of ultra clean coal obtained by chemical demineralisation

Energy Technology Data Exchange (ETDEWEB)

F. Rubiera; A. Arenillas; B. Arias; J.J. Pis; I. Suarez-Ruiz; K.M. Steel; J.W. Patrick [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

2003-10-01

The increasing environmental concern caused by the use of fossil fuels and the concomitant need for improved combustion efficiency is leading to the development of new coal cleaning and utilisation processes. However, the benefits achieved by the removal of most mineral matter from coal either by physical or chemical methods can be annulled if poor coal combustibility characteristics are attained. In this work a high volatile bituminous coal with 6% ash content was subjected to chemical demineralisation via hydrofluoric and nitric acid leaching, the ash content of the clean coal was reduced to 0.3%. The original and treated coals were devolatilised in a drop tube furnace and the structure and morphology of the resultant chars was analysed by optical and scanning electron microscopies. The reactivity characteristics of the chars were studied by isothermal combustion tests in air at different temperatures in a thermogravimetric system. Comparison of the combustion behaviour and pollutant emissions of both coals was conducted in a drop tube furnace operating at 1000{sup o}C. The results of this work indicate that the char obtained from the chemically treated coal presents very different structure, morphology and reactivity behaviour than the char from the original coal. The changes induced by the chemical treatment increased the combustion efficiency determined in the drop tube furnace, in fact higher burnout levels were obtained for the demineralised coal.

Review of cleaning techniques and their effects on the chemical composition of foliar samples

Energy Technology Data Exchange (ETDEWEB)

Rossini Oliva, S.; Raitio, H.

2003-07-01

Chemical foliar analysis is a tool widely used to study tree nutrition and to monitor the impact and extent of air pollutants. This paper reviews a number of cleaning methods, and the effects of cleaning on foliar chemistry. Cleaning may include mechanical techniques such as the use of dry or moistened tissues, shaking, blowing, and brushing, or use various washing techniques with water or other solvents. Owing to the diversity of plant species, tissue differences, etc., there is no standard procedure for all kinds of samples. Analysis of uncleaned leaves is considered a good method for assessing the degree of air contamination because it provides an estimate of the element content of the deposits on leaf surfaces or when the analysis is aimed at the investigation of transfer of elements along the food chain. Sample cleaning is recommended in order (1) to investigate the transfer rate of chemical elements from soil to plants, (2) to qualify the washoff of dry deposition from foliage and (3) to separate superficially absorbed and biomass-incorporated elements. Since there is not a standard cleaning procedure for all kinds of samples and aims, it is advised to conduct a pilot study in order to be able to establish a cleaning procedure to provide reliable foliar data. (orig.)

Chemical cleaning of PWR steam generators: application at Nogent 1

International Nuclear Information System (INIS)

Fiquet, J.M.; Veysset, J.P.; Esteban, L.; Saurin, P.

1990-01-01

EDF has developed and patented a chemical cleaning process for PWR steam generators, based on the use of a mixture of organic acids in order to: - dissolve iron oxides and copper with a single solution; - clean dented crevices. Qualification tests have permitted to demonstrate effectiveness of the solution and its inocuousness related to steam generator materials. The process, the license of which belongs to SOMAFER R.A. and FRAMATOME, has been implemented in France at Nogent. The goal was to dissolve iron oxides allowing metallic particles, aggregated on the tubesheet, to be released and mechanically removed. The effectiveness was satisfactory and this treatment is to be extended to other units [fr

A Study on an Executive Technique and Activation of Clean Production in Chemical Industry

Energy Technology Data Exchange (ETDEWEB)

Kong, Seong Yong; Lee, Hee Seok; Kim, Kang Seok [Korea Environment Institute, Seoul (Korea)

2000-12-01

Clean production does not only make the sustainable development possible through preventing the deterioration of the environmental pollution from the expansion of industrialization but also enhance the company's competitiveness. Clean production is required by all industrial fields but is the most important in chemical industry. The Government has made efforts to change the domestic industrial structure to the environmental-friendly structure through developing the research. However, the domestic industry has not yet activated overall except some large companies, which has concretized the activation of clean production. Especially, the medium and small companies are more sluggish due to the inferiority of capital and technology. With recognizing that the main body of clean production is a company, the effort based on the Government and the academic world, without companies' positive, will cannot help being limited in effects. Therefore, it is necessary to trigger the schemes that urge the companies' motivation to show the effects from the support that have concentrated in hardware like technology until now. It seems to be very important that the guidebook for clean production, which a company can easily adopt, is developed and spread. This report provides the guidebook for clean production that managers and engineers can easily understand and approach in a producing field and presents the scheme to promote clean production, for chemical industry that is seriously required clean production. Even if the presented contents are not perfect, they can be applied to the development of the Government's policy and the administrative activities of companies for clean production as a useful data. 53 refs., 5 figs., 30 tabs.

Is dry cleaning all wet?

International Nuclear Information System (INIS)

Ryan, M.

1993-01-01

Chemical solvents from dry cleaning, particularly perchloroethylene (perc), have contributed to groundwater contamination, significant levels of air pollution in and around cleaners, and chemical accumulation in food. Questions are being raised about the process of cleaning clothes with chemical, and other less toxic cleaning methods are being explored. The EPA has focused attention on the 50 year old Friedburg method of cleaning, Ecoclean, which uses no dangerous chemicals and achieves comparable results. Unfortunately, the cleaning industry is resistant to change, so cutting back on amount of clothes that need dry cleaning and making sure labels aren't exaggerating when they say dry clean only, is frequently the only consumer option now

Technological procedure for chemical cleaning prior to re-pyritization of H2O-H2S isotopic exchange installations

International Nuclear Information System (INIS)

Stefanescu, I.; Smaranda, D.; Titescu, Gh.

1996-01-01

In normal operation the anti-corrosive shielding of the GS installations undergo a slow, irreversible degradation in time so that after 6 - 8 years their protection characteristics break down. In order to put them back in operation the regeneration of anti-corrosive is required. The procedure achieved at ICIS - Rm.Valcea consists in chemical cleaning of the impaired layers and re-pyritization of the interior surface of installations. Chemical cleaning include the following operations: - mechanical cleaning; - water washing; - alkaline washing with sodium hydroxide, tri-sodium phosphate and sodium tri-polyphosphate; - final mechanical cleaning; - neutralizing washing; - chemical cleaning with phosphoric acid solution; - neutralizing washing. After applying this procedure, the surface is prepared for the pyritization regeneration of the anti-corrosive shielding which ensures the prolongation of the equipment service lifetime with another six year period

The importance of chemical components in cleaning agents for the indoor environment

DEFF Research Database (Denmark)

Vejrup, Karl Ventzel

In order to evaluate the importance for the indoor environment of chemical compounds in cleaning agents, the emission of VOCs (Volatile Organic Compounds) from 10 selected cleaning agents and the content of LAS (Linear AlkanbenzeneSulfonate) in dust samples from 7 buildings were investigated.The...... of LAS between smooth floored corridors to carpeted offices, are apparently also of importance for the LAS content in individual rooms.The amounts of LAS found in the dust samples indicated that LAS may be of importance for the indoor environment, but inadequate knowledge about how low concentrations...... investigation of VOC emission from 10 selected cleaning agents showed that it was useful to classify the VOCs into two groups: nonpolar VOCs and polar VOCs.The nonpolar VOCs consisted of several hundred different compounds, mainly terpenes typically used as perfume in cleaning agents. The nonpolar VOC...

Gas plant cleaning case history

Energy Technology Data Exchange (ETDEWEB)

Woods, B

1971-03-22

Basic steps to be taken before using any cleaning method are select a responsible group and give it full responsibility; know the problem, what type of fouling, lab samples, amount of material, time and cost; sell the idea to management; maintain the cleaning equipment; and follow up each cleaning operation. These principles have been applied to advantage in the amine contractor at Taylor, a vessel 60 ft high with 78-in. OD, containing carbon steel deck trays with stainless steel caps. The original attempt to clean with wire scrapers manually involved much lost time and several crews. There was limited space in the tray vessels, design created areas difficult to clean, working conditions were unpleasant, equipment downtime was extended, labor cost was high, and the final result was not satisfactory. Chemical cleaning was substituted, preceded by a water wash. Five hours of caustic wash with a 3% solution at 170$F were followed by a water wash, an acid wash, 1-hr neutralization with a weak soda ash solution, and finally passivation to eliminate iron oxide. For the acid wash, sulfamic acid was found best, in 10% concentration for 4 hr. Cascading was most economical, but flooding has been employed sometimes at 2-1/2 times the cost, to reach all the dark corners.

Re-establishing filtering capabilities of machined porous beryllium via chemical reduction and cleaning

International Nuclear Information System (INIS)

Randall, W.L.

1975-01-01

Porous beryllium is furnished in sheets of varying sizes and thickness; it is therefore necessary that it be machined into specified sizes. A chemical reduction and cleaning procedure was devised to remove the disrupted surface, open the sealed pores of the material, and clean entrapped contaminates from the internal structure. Dimensional stability can be closely controlled and material size is of no consequence. (U.S.)

Substantiation of basic scheme of grain cleaning machine for preparation of agricultural crops seeds

Science.gov (United States)

Giyevskiy, A. M.; Orobinsky, V. I.; Tarasenko, A. P.; Chernyshov, A. V.; Kurilov, D. O.

2018-03-01

The article presents data on the feasibility of the concept of a high-efficiency seed cleaner with the consistent use of the air flow in aspiration and the multi-tier placement of the sorting grids in grating mills. As a result of modeling, the directions for further improvement of air-screen seed cleaning machines have been identified: an increase in the proportion of sorting grids in the mills up to 70 ... 80% and an increase in the speed of the air flow in the channel of the pre-filter cleaning up to 8.0 m / s. Experiments have established the competence of using mathematical modeling of airflow in the pneumatic system with the use of a finite-volume method for solving hydrodynamic equations for substantiating the basic parameters of the pneumatic system.

ENHANCED CHEMICAL CLEANING: EFFECTIVENESS OF THE UV LAMP TO DECOMPOSE OXALATES

Energy Technology Data Exchange (ETDEWEB)

Ketusky, E.; Huff, T.; Sudduth, C.

2010-01-19

Enhanced Chemical Cleaning is a new process scheduled to begin cleaning Savannah River Site High Level Waste Tanks in 2012. It is an improvement over the current chemical cleaning method, in that it minimizes downstream impacts on the High Level Waste System. It is based on a state of the art scale removal process used on the secondary side of nuclear power plants, with modifications to accommodate the unique constraints created by the tanks. Both Enhanced Chemical Cleaning and the scale removal process are founded on dissolving metal oxides/hydroxides using oxalic acid, with subsequent oxalate decomposition via hydroxylation using ozone or peroxide, and UV light as a catalyst. A divergence Enhanced Chemical Cleaning has from nuclear power scale removal is the significantly increased solids concentration during oxalate decomposition. These solids can limit the ability of the UV light to create hydroxyl radicals, either by limiting the ability of the light to penetrate through the solution, or by increasing the fouling rate on the UV light. Both will decrease the overall catalytic effectiveness, thereby decreasing the concentration of formed hydroxyl radicals. The hydroxyl radicals are the driving force behind the oxalate decomposition. To understand the impact of increased solids, testing was performed using a medium pressure UV light inside an ozone supplied Oxalate Decomposition Reactor. Using a dissolved metal sludge simulant with an initial oxalate concentration greater than 12,000 ppm, and an initial pH of about 2.0, the spent acid solution was recirculated through the reactor, while the UV light was allowed to foul. For the first few hours, the oxalate decomposition rate was about 1,300 ppm/hour. After about 3 hours, enough time for the UV lamp to foul, the oxalate decomposition rate decreased to about 500 ppm/hour. The decomposition rate then remained roughly constant for the next 16 hours. Overall, testing showed that the oxalate destruction rate decreased

Decrudding and chemical cleaning of carbon steel components - an evaluation

International Nuclear Information System (INIS)

Gaonkar, K.B.; Elayathu, N.S.D.; Shibad, P.R.; Gadiyar, H.S.

1982-01-01

Corrosion and accumulation of corrosion products on the surfaces of structural components and plant equipments can cause se vereoperational problems during service. An illustration is the heat exchanger systems in nuclear power stations. Development and standardisation of appropriate chemical cleaning and decontamination procedures and their evaluation hence merit serious consideration. A number of chemical cleaning procedures using formulations based on hydrochloric and citric acid solutions have been examined to study their crud dissolving and derusting ability in addition to the attack on base material. The compositions were chosen: (1) along with complexing agents EDTA and ammonium citrate, (2) with pH control, and (3) with the use of inhibitors acridine, rhodine, hexamine and phenyl-thiourea. The evaluations have been made at 28 and 60 deg C. Rusted carbon steel coupons having a rust of 10-12 mg/cm 2 on the surface have been used for the purpose of the above evaluations. Data on corrosion rates of monel and cupronickel (70:30) in the descaling solutions have also been presented. Results on the above evaluation studies have been discussed. (author)

Overview of shoreline cleaning agents

International Nuclear Information System (INIS)

Clayton, J.

1992-01-01

Chemical cleaning agents may be used to promote release of stranded oil from shorelines for reasons including biological sensitivity of indigenous fauna and flora to the oil, amenity considerations of the shoreline, or concern about refloating of the oil and subsequent stranding on adjacent shorelines. While use of chemical cleaning agents may be appropriate under proper toxic responses in circumstances, certain limitations should be recognized. The potential for toxic responses in indigenous fauna and flora to the cleaning agents must be considered. Enhanced penetration of oil into permeable shorelines following treatment with chemical cleaning agents also is not desirable. However, if conditions related to toxicity and substrate permeability are determined to be acceptable, the use of chemical cleaning agents for treatment of stranded oil can be considered. Chemical agents for cleaning oiled shorelines can be grouped into three categories: (1) non-surfactant-based solvents, (2) chemical dispersants, and (3) formulations especially designed to release stranded oil from shoreline substrates (i.e., shoreline-cleaning-agents). Depending on the specific circumstances present on an oiled shoreline, it is generally desirable that chemical agents used for cleaning will release oil from shoreline substrate(s) to surface waters. Recovery of the oil can then be accomplished by mechanical procedures such as booming and skimming operations

Effectiveness of bone cleaning process using chemical and entomology approaches: time and cost.

Science.gov (United States)

Lai, Poh Soon; Khoo, Lay See; Mohd Hilmi, Saidin; Ahmad Hafizam, Hasmi; Mohd Shah, Mahmood; Nurliza, Abdullah; Nazni, Wasi Ahmad

2015-08-01

Skeletal examination is an important aspect of forensic pathology practice, requiring effective bone cleaning with minimal artefact. This study was conducted to compare between chemical and entomology methods of bone cleaning. Ten subjects between 20 and 40 years old who underwent uncomplicated medico-legal autopsies at the Institute of Forensic Medicine Malaysia were randomly chosen for this descriptive cross sectional study. The sternum bone was divided into 4 parts, each part subjected to a different cleaning method, being two chemical approaches i.e. laundry detergent and a combination of 6% hydrogen peroxide and powder sodium bicarbonate and two entomology approaches using 2nd instar maggots of Chrysomyia rufifacies and Ophyra spinigera. A scoring system for grading the outcome of cleaning was used. The effectiveness of the methods was evaluated based on average weight reduction per day and median number of days to achieve the average score of less than 1.5 within 12 days of the bone cleaning process. Using maggots was the most time-effective and costeffective method, achieving an average weight reduction of 1.4 gm per day, a median of 11.3 days to achieve the desired score and an average cost of MYR 4.10 per case to reach the desired score within 12 days. This conclusion was supported by blind validation by forensic specialists achieving a 77.8% preference for maggots. Emission scanning electron microscopy evaluation also revealed that maggots especially Chrysomyia rufifacies preserved the original condition of the bones better allowing improved elucidation of bone injuries in future real cases.

Method of and apparatus for cleaning garments and soft goods contaminated with nuclear, chemical and/or biological contaminants

International Nuclear Information System (INIS)

Fowler, D.E.

1989-01-01

A method is described for decontaminating garments, soft good or mixtures thereof contaminated with radioactive particulates, toxin, chemical, and biological contaminants comprising the steps of: (a) depositing contaminated garments, soft goods or mixtures thereof in a cleaning drum; (b) charging the drum with a cleaning solvent in which the chemical contaminants are soluble; (c) agitating the drum during a wash cycle to separate radioactive, toxin, biological particulate matter of mixtures thereof from the garments; (d) draining the drum of the dry cleaning solvent which contains suspended particulate contaminants and dissolved chemical contaminants; (e) contacting the drained solvent with both a neutralizing agent and an oxidizing agent, the neutralizing agent being selected from the group consisting of sodium hydroxide, potassium hydroxide and mixtures thereof and having a concentration greater than one (1.0) normal; (f) rinsing the garments, soft goods or mixtures thereof by circulating clean solvent from a solvent tank through the drum thereby effecting additional removal and flushing of particulate and chemical contaminants; (g) filtering the circulated solvent to remove the particulate material suspended in the solvent prior to addition to the drum; and (h) preferentially adsorbing the chemical contaminants dissolved in the circulated solvent prior to addition to the drum

Fabrication of superhydrophilic or superhydrophobic self-cleaning metal surfaces using picosecond laser pulses and chemical fluorination

Science.gov (United States)

Zheng, Buxiang; Jiang, Gedong; Wang, Wenjun; Mei, Xuesong

2016-05-01

Bioinspired superhydrophilic/phobic self-cleaning surfaces have recently drawn a lot of interest in both fundamental and applied research. A hybrid method to produce the self-cleaning property of micro/nanostructured surface using ultra-fast laser pulses followed by chemical fluorination is proposed. The typical micro/nanocomposite structures that form from microporous arrays and microgroove groups have been processed by picosecond laser on titanium alloy surface. The surface hydrophilic/phobic and self-cleaning properties of micro/nanostructures before and after fluorination with fluoroalkyl-silane were investigated using surface contact angle measurements. The results indicate that surface properties change from hydrophilic to hydrophobic after fluorination, and the micro/nanostructured surface with increased roughness contributes to the improvement of surface hydrophobicity. The micro/nanomodification can make the original hydrophilic titanium alloy surface more hydrophilic or superhydrophilic. It also can make an originally hydrophobic fluorinated titanium alloy surface more hydrophobic or superhydrophobic. The produced micro/nanostructured titanium alloy surfaces show excellent self-cleaning properties regardless of the fluorination treatment, although the fluorinated surfaces have slightly better self-cleaning properties. It is found that surface treatment using ultra-fast laser pulses and subsequent chemical fluorination is an effective way to manipulate surface wettability and obtain self-cleaning properties.

Selected works of basic research on the physics and technology of accelerator driven clean nuclear power system

International Nuclear Information System (INIS)

Zhao Zhixiang

2002-01-01

38 theses are presented in this selected works of basic research on the physics and technology of accelerator driven clean nuclear power system. It includes reactor physics and experiment, accelerators physics and technology, nuclear physics, material research and partitioning. 13 abstracts, which has been presented on magazines home and abroad, are collected in the appendix

Risk in cleaning: chemical and physical exposure.

Science.gov (United States)

Wolkoff, P; Schneider, T; Kildesø, J; Degerth, R; Jaroszewski, M; Schunk, H

1998-04-23

Cleaning is a large enterprise involving a large fraction of the workforce worldwide. A broad spectrum of cleaning agents has been developed to facilitate dust and dirt removal, for disinfection and surface maintenance. The cleaning agents are used in large quantities throughout the world. Although a complex pattern of exposure to cleaning agents and resulting health problems, such as allergies and asthma, are reported among cleaners, only a few surveys of this type of product have been performed. This paper gives a broad introduction to cleaning agents and the impact of cleaning on cleaners, occupants of indoor environments, and the quality of cleaning. Cleaning agents are usually grouped into different product categories according to their technical functions and the purpose of their use (e.g. disinfectants and surface care products). The paper also indicates the adverse health and comfort effects associated with the use of these agents in connection with the cleaning process. The paper identifies disinfectants as the most hazardous group of cleaning agents. Cleaning agents contain evaporative and non-evaporative substances. The major toxicologically significant constituents of the former are volatile organic compounds (VOCs), defined as substances with boiling points in the range of 0 degree C to about 400 degrees C. Although laboratory emission testing has shown many VOCs with quite different time-concentration profiles, few field studies have been carried out measuring the exposure of cleaners. However, both field studies and emission testing indicate that the use of cleaning agents results in a temporal increase in the overall VOC level. This increase may occur during the cleaning process and thus it can enhance the probability of increased short-term exposure of the cleaners. However, the increased levels can also be present after the cleaning and result in an overall increased VOC level that can possibly affect the indoor air quality (IAQ) perceived by

Handbook of Basic Tables for Chemical Analysis. Final report

International Nuclear Information System (INIS)

Bruno, T.J.; Svoronos, P.D.N.

1988-04-01

This work began as a slim booklet prepared by one of the authors (TJB) to accompany a course on chemical instrumentation presented at the National Bureau of Standards, Boulder Laboratories. The booklet contained tables on chromatography, spectroscopy, and chemical (wet) methods, and was intended to provide the students with enough basic data to design their own analytical methods and procedures. Shortly thereafter, with the co-authorship of Prof. Paris D. N. Svoronos, it was expanded into a more-extensive compilation entitled Basic Tables for Chemical Analysis, published as National Bureau of Standards Technical Note 1096. That work has now been expanded and updated into the present body of tables. Although there have been considerable changes since the first version of these tables, the aim has remained essentially the same. The authors have tried to provide a single source of information for those practicing scientists and research students who must use various aspects of chemical analysis in their work. In this respect, it is geared less toward the researcher in analytical chemistry than to those practitioners in other chemical disciplines who must have routine use of chemical analysis

Surface modification of titanium membrane by chemical vapor deposition and its electrochemical self-cleaning

Energy Technology Data Exchange (ETDEWEB)

Li, X.W., E-mail: lynnww@sohu.com [School of Electronic and Information Engieering, Tianjin university, Tianjin, 300072 (China); School of Electronics Information Engieering, Tianjin University of Technology, Tianjin, 300384 (China); Li, J.X. [Tianjin Polytechnic University, Tianjin 300160 (China); Gao, C.Y. [Chinese Peoples Armed Police Forces Academy, Langfang 065000 (China); Chang, M. [School of Electronic and Information Engieering, Tianjin university, Tianjin, 300072 (China); School of Electronics Information Engieering, Tianjin University of Technology, Tianjin, 300384 (China)

2011-10-15

Membrane separation is applied widely in many fields, while concentration polarization and membrane fouling, limiting its promotion and application greatly, are the bottlenecks in membrane application. Among which, membrane fouling is irreversible, membrane must be periodically cleaned or even replaced to restore permeability. Membrane cleaning has become one of Key issues in membrane separation areas. Considering incomparable electrochemical advantages of boron-doped diamond (BDD) film electrode over conventional electrode, a new composite membrane Ti/BDD, made by depositing CVD (chemical vapor deposition) boron-doped diamond film on titanium(Ti) membrane to modify porous titanium surface, that can be cleaned electrochemically is proposed. Feasibility of its preparation and application is discussed in this paper. Results shows that based on the unique electrochemical properties of diamond, cleaning level of this composite Ti/BDD membrane is significantly increased, making membrane life and efficiency improved prominently.

Surface modification of titanium membrane by chemical vapor deposition and its electrochemical self-cleaning

International Nuclear Information System (INIS)

Li, X.W.; Li, J.X.; Gao, C.Y.; Chang, M.

2011-01-01

Membrane separation is applied widely in many fields, while concentration polarization and membrane fouling, limiting its promotion and application greatly, are the bottlenecks in membrane application. Among which, membrane fouling is irreversible, membrane must be periodically cleaned or even replaced to restore permeability. Membrane cleaning has become one of Key issues in membrane separation areas. Considering incomparable electrochemical advantages of boron-doped diamond (BDD) film electrode over conventional electrode, a new composite membrane Ti/BDD, made by depositing CVD (chemical vapor deposition) boron-doped diamond film on titanium(Ti) membrane to modify porous titanium surface, that can be cleaned electrochemically is proposed. Feasibility of its preparation and application is discussed in this paper. Results shows that based on the unique electrochemical properties of diamond, cleaning level of this composite Ti/BDD membrane is significantly increased, making membrane life and efficiency improved prominently.

Electrospun Superhydrophobic Self-Cleaning Materials

Science.gov (United States)

Zhao, Yong; Wang, Nü

In this chapter, we introduce the wettability of electrospinning products. Especially, we concentrate on the fabrication, characteristics, and applications of the electrospun self-cleaning materials. Self-cleaning materials are typical nature-inspired artificial materials learning from such as lotus leaf and many other plants or animals. Self-cleaning materials usually rely on a superhydrophobic surface, which should be of low surface free energy as well as large surface roughness. Electrospinning method is such a method that could facilely shape various hydrophobic polymers into ultrathin fibers with tunable surface microstructures. It means the electrospun products are of very large specific area, which satisfy the two basic conditions in preparing superhydrophobic surfaces. Therefore, in the last decade, scientists put forward a good few of elegant approaches to fabricate superhydrophobic materials by electrospinning. These methods can be generally classified into two routes. One is a direct route that creates superhydrophobic electrospun films from hydrophobic materials. Another is an indirect route that decorates electrospun nanofibers (no matter hydrophobic or hydrophilic) with hydrophobic chemicals. We first introduce some representative works on the fabrication of superhydrophobic self-cleaning materials by electrospinning method. Then we show some applications of these superhydrophobic materials. Finally, we give a brief personal perspective on this area.

Laser cleaning on Roman coins

Science.gov (United States)

Drakaki, E.; Karydas, A. G.; Klinkenberg, B.; Kokkoris, M.; Serafetinides, A. A.; Stavrou, E.; Vlastou, R.; Zarkadas, C.

Ancient metal objects react with moisture and environmental chemicals to form various corrosion products. Because of the unique character and high value of such objects, any cleaning procedure should guarantee minimum destructiveness. The most common treatment used is mechanical stripping, in which it is difficult to avoid surface damage when employed. Lasers are currently being tested for a wide range of conservation applications. Since they are highly controllable and can be selectively applied, lasers can be used to achieve more effective and safer cleaning of archaeological artifacts and protect their surface details. The basic criterion that motivated us to use lasers to clean Roman coins was the requirement of pulsed emission, in order to minimize heat-induced damages. In fact, the laser interaction with the coins has to be short enough, to produce a fast removal of the encrustation, avoiding heat conduction into the substrate. The cleaning effects of three lasers operating at different wavelengths, namely a TEA CO2 laser emitting at 10.6 μm, an Er:YAG laser at 2.94 μm, and a 2ω-Nd:YAG laser at 532 nm have been compared on corroded Romans coins and various atomic and nuclear techniques have also been applied to evaluate the efficiency of the applied procedure.

PWR steam generator chemical cleaning, Phase I. Final report

International Nuclear Information System (INIS)

Rothstein, S.

1978-07-01

United Nuclear Industries (UNI) entered into a subcontract with Consolidated Edison Company of New York (Con Ed) on August 8, 1977, for the purpose of developing methods to chemically clean the secondary side tube to tube support crevices of the steam generators of Indian Point Nos. 1 and 2 PWR plants. This document represents the first reporting on activities performed for Phase I of this effort. Specifically, this report contains the results of a literature search performed by UNI for the purpose of determining state-of-the-art chemical solvents and methods for decontaminating nuclear reactor steam generators. The results of the search sought to accomplish two objectives: (1) identify solvents beyond those proposed at present by UNI and Con Ed for the test program, and (2) confirm the appropriateness of solvents and methods of decontamination currently in use by UNI

Reactive Ion Etching as Cleaning Method Post Chemical Mechanical Polishing for Phase Change Memory Device

International Nuclear Information System (INIS)

Min, Zhong; Zhi-Tang, Song; Bo, Liu; Song-Lin, Feng; Bomy, Chen

2008-01-01

In order to improve nano-scale phase change memory performance, a super-clean interface should be obtained after chemical mechanical polishing (CMP) of Ge 2 Sb 2 Te 5 phase change films. We use reactive ion etching (RIE) as the cleaning method. The cleaning effect is analysed by scanning electron microscopy and an energy dispersive spectrometer. The results show that particle residue on the surface has been removed. Meanwhile, Ge 2 Sb 2 Te 5 material stoichiometric content ratios are unchanged. After the top electrode is deposited, current-voltage characteristics test demonstrates that the set threshold voltage is reduced from 13 V to 2.7V and the threshold current from 0.1mA to 0.025mA. Furthermore, we analyse the RIE cleaning principle and compare it with the ultrasonic method

In-Situ Ion Source Cleaning: Review of Chemical Mechanisms and Evaluation Data at Production Fabs

International Nuclear Information System (INIS)

Kaim, R.; Bishop, S.; Byl, O.; Eldridge, D.; Marganski, P.; Mayer, J.; Sweeney, J.; Yedave, S.; Fuchs, D.; Spreitzer, S.; Vogel, J.; Dunn, J.; Lundquist, P.; Rolland, J.; Romig, T.; Newman, D.; Mitchell, M.; Ditzler, K.

2008-01-01

Since the concept of chemical in-situ ion implanter cleaning was introduced at IIT2006 [1], evaluations of the XeF 2 cleaning technology have taken place or are ongoing at more than 40 production fabs worldwide. Testing has been focused on assessing effects of cleaning in the source arc chamber and extraction regions. In this paper we describe use of the cleaning technology in a production environment and summarize evaluation data showing advantages of the technology for improving ion source life, reducing glitching, improving beam auto-tuning and avoiding species cross-contamination. More details of the evaluations are given in several separate papers submitted to this Conference. We have supplemented the fab production data with laboratory experiments designed to investigate the reactivity of XeF 2 and fundamental aspects of the source deposition and cleaning processes. These experiments are summarized here, and more details can be found in separate papers submitted to this Conference

Weld region corrosion during chemical cleaning of PWR [pressurized-water reactor] steam generators: Volume 2, Tests and analyses: Final report

International Nuclear Information System (INIS)

Barna, J.L.; Bozeka, S.A.; Jevec, J.M.

1987-07-01

The potential for preferential corrosion of steam generator weld regions during chemical cleaning using the generic SGOG solvents was investigated. The investigations included development and use of a corrosion assessment test facility which measured corrosion currents in a realistic model of the steam generator geometry in the vicinity of a specific weld during a simulated chemical dissolution of sludge consisting of essentially pure magnetite. A corrosion monitoring technique was developed and qualified. In this technique free corrosion rates measured by linear polarization techniques are added to corrosion rates calculated from galvanic current measured using a zero resistance ammeter to give an estimate of total corrosion rate for a galvanically corroding material. An analytic modeling technique was developed and proved useful in determining the size requirements for the weld region mockup used in the corrosion assessment test facility. The technique predicted galvanic corrosion rates consistent with that observed in a corrosion assessement test when polarization data used as model input were obtained on-line during the test. The test results obtained during this investigation indicated that chemical cleaning using the SGOG magnetite dissolution solvent can be performed with a small amount of corrosion of secondary side internals and pressure boundary welds. The maximum weld region corrosion measured during a typical chemical cleaning cycle to remove essentially pure magnetite sludge was about 8 mils. However, additional site specific weld region corrosion assessment testing and qualification will be required prior to chemical cleaning steam generators at a specific plant. Recommendations for site specific qualification of chemical cleaning processes and for use of process monitors and on-line corrosion instrumentation are included in this report

A study on the chemical cleaning process and its qualification test by eddy current testing

Energy Technology Data Exchange (ETDEWEB)

Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo [KHNP Central Research Institute, Daejeon (Korea, Republic of); Min, Kyoung Mahn [UMI Inc., Daejeon (Korea, Republic of)

2013-12-15

Steam Generator (SG) tube, as a barrier isolating the primary coolant system from the secondary side of nuclear power plants (NPP), must maintain the structural integrity for the public safety and their efficient power generation. So, SG tubes are subject to the periodic examination and the repairs if needed so that any defective tubes are not in service. Recently, corrosion related degradations were detected in the tubes of the domestic OPR-1000 NPP, as a form of axially oriented outer diameter stress corrosion cracking (ODSCC). According to the studies on the factors causing the heat fouling as well as developing corrosion cracking, densely scaled deposits on the secondary side of the SG tubes are mainly known to be problematic causing the adverse impacts against the soundness of the SG tubes. Therefore, the processes of various cleaning methods efficiently to dissolve and remove the deposits have been applied as well as it is imperative to maintain the structural integrity of the tubes after exposing to the cleaning agent. So qualification test (QT) should be carried out to assess the perfection of the chemical cleaning and QT is to apply the processes and to do ECT. In this paper, the chemical cleaning processes to dissolve and remove the scaled deposits are introduced and results of ECT on the artificial crack specimens to determine the effectiveness of those processes are represented.

Use of a fluorescent chemical as a quality indicator for a hospital cleaning program.

Science.gov (United States)

Blue, Jennifer; O'Neill, Cindy; Speziale, Paul; Revill, Jeff; Ramage, Lee; Ballantyne, Lisa

2008-01-01

Hamilton Health Sciences is a large teaching hospital with over 1,000 beds and consists of three acute care sites, one Regional Cancer Center and two Rehabilitation/Chronic Care facilities. An environmental cleaning pilot project was initiated at the acute care Henderson site, following an outbreak of vancomycin-resistant Enterococcus (VRE). Healthcare-associated infections (HAI) due to antibiotic-resistant organisms are increasing in Southern Ontario. Environmental cleaning plays a key role in eradicating resistant organisms that live in hospital environments, thereby helping to reduce HAIs. The environmental cleaning practices on the Orthopaedic Unit were identified as a contributing factor to the VRE outbreak after visual assessments were completed using a Brevis GlitterBug product, a chemical that fluoresces under an ultraviolet (UV) lamp. These findings led to a hospital-wide cleaning improvement initiative on all units except critical care areas. The GlitterBug potion was employed by Infection Control and Customer Support Services (CSS) as a tool to evaluate the daily cleaning of patient washrooms as well as discharge cleaning of contact precaution isolation rooms. Over a four-week period, the GlitterBug potion was applied to seven frequently touched standard targets in randomly selected patient bathrooms on each unit and 14 frequently touched targets prior to cleaning in the rooms used for isolation. The targets were then evaluated using the UV lamp to detect objects that were not cleaned and the results were recorded on a standardized form. The rate of targets cleaned versus the targets missed was calculated. The overall rate for daily cleaning of bathrooms and cleaning of isolation rooms was poor with only 23% of the targets cleaned. Based on these findings, several interventions were implemented. This resulted in a significant improvement in cleaning practices during the pilot project. Greater than 80% of the targets were cleaned compared to the baseline

Chemical cleaning of nuclear (PWR) steam generators

International Nuclear Information System (INIS)

Welty, C.S. Jr.; Mundis, J.A.

1982-01-01

This paper reports on a significant research program sponsored by a group of utilities (the Steam Generator Owners Group), which was undertaken to develop a process to chemically remove corrosion product deposits from the secondary side of pressurized water reactor (PWR) power plant steam generators. Results of this work have defined a process (solvent system and application methods) that is capable of removing sludge and tube-to-tube support plate crevice corrosion products generated during operation with all-volatile treatment (AVT) water chemistry. Considers a plant-specific test program that includes all materials in the steam generator to be cleaned and accounts for the physical locations (proximity and contact) of those materials. Points out that prior to applying the process in an operational unit, the utility, with the participation of the NSSR vendor, must define allowable total corrosion to the materials of construction of the unit

Mathematical modelling of flux recovery during chemical cleaning of tubular membrane fouled with whey proteins

Directory of Open Access Journals (Sweden)

Marković Jelena Đ.

2009-01-01

Full Text Available Membrane process efficiency in the dairy industry is impaired by the formation of deposits during filtration processes. This work describes cleaning procedures for ceramic tubular membrane (50 nm fouled with whey proteins. Also, mathematical modelling was performed to obtain models which allow deeper insight into the mechanisms involved during cleaning procedures. The caustic solutions (0.2%w/w, 0.4%w/w and 1.0%w/w NaOH and the mixture of two commercial detergents (0.8%w/w P3-ultrasil 69+0.5% w/w P3-ultrasil 67 and 1.2% P3-ultrasil 69+0.75 P3-ultrasil 67 were used as chemical cleaning agents. The results showed that the best flux recovery was achieved with 0.4%w/w NaOH solution. After analyzing the experimental data, five parameter and six parameter kinetic models were suggested for alkali and detergent cleaning, respectively. The changes of total and specific resistances, as well as the change of the effective pore diameter and deposit thickness during cleaning are estimated by applying these models.

Forecasting global developments in the basic chemical industry for environmental policy analysis

International Nuclear Information System (INIS)

Broeren, M.L.M.; Saygin, D.; Patel, M.K.

2014-01-01

The chemical sector is the largest industrial energy user, but detailed analysis of its energy use developments lags behind other energy-intensive sectors. A cost-driven forecasting model for basic chemicals production is developed, accounting for regional production costs, demand growth and stock turnover. The model determines the global production capacity placement, implementation of energy-efficient Best Practice Technology (BPT) and global carbon dioxide (CO 2 ) emissions for the period 2010–2030. Subsequently, the effects of energy and climate policies on these parameters are quantified. About 60% of new basic chemical production capacity is projected to be placed in non-OECD regions by 2030 due to low energy prices. While global production increases by 80% between 2010 and 2030, the OECD's production capacity share decreases from 40% to 20% and global emissions increase by 50%. Energy pricing and climate policies are found to reduce 2030 CO 2 emissions by 5–15% relative to the baseline developments by increasing BPT implementation. Maximum BPT implementation results in a 25% reduction. Further emission reductions require measures beyond energy-efficient technologies. The model is useful to estimate general trends related to basic chemicals production, but improved data from the chemical sector is required to expand the analysis to additional technologies and chemicals. - Highlights: • We develop a global cost-driven forecasting model for the basic chemical sector. • We study regional production, energy-efficient technology, emissions and policies. • Between 2010 and 2030, 60% of new chemicals capacity is built in non-OECD regions. • Global CO 2 emissions rise by 50%, but climate policies may limit this to 30–40%. • Measures beyond energy efficiency are needed to prevent increasing CO 2 emissions

Alternative Chemical Cleaning Methods for High Level Waste Tanks: Actual Waste Testing with SRS Tank 5F Sludge

Energy Technology Data Exchange (ETDEWEB)

King, William D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hay, Michael S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-08-30

Solubility testing with actual High Level Waste tank sludge has been conducted in order to evaluate several alternative chemical cleaning technologies for the dissolution of sludge residuals remaining in the tanks after the exhaustion of mechanical cleaning and sludge sluicing efforts. Tests were conducted with archived Savannah River Site (SRS) radioactive sludge solids that had been retrieved from Tank 5F in order to determine the effectiveness of an optimized, dilute oxalic/nitric acid cleaning reagent toward dissolving the bulk non-radioactive waste components. Solubility tests were performed by direct sludge contact with the oxalic/nitric acid reagent and with sludge that had been pretreated and acidified with dilute nitric acid. For comparison purposes, separate samples were also contacted with pure, concentrated oxalic acid following current baseline tank chemical cleaning methods. One goal of testing with the optimized reagent was to compare the total amounts of oxalic acid and water required for sludge dissolution using the baseline and optimized cleaning methods. A second objective was to compare the two methods with regard to the dissolution of actinide species known to be drivers for SRS tank closure Performance Assessments (PA). Additionally, solubility tests were conducted with Tank 5 sludge using acidic and caustic permanganate-based methods focused on the “targeted” dissolution of actinide species.

The AREVA C3 concept. Customized chemical cleaning as an essential part of steam generator asset management

International Nuclear Information System (INIS)

Weiss, Steffen

2011-01-01

As the nuclear industry moves forward and the world's power demand increases, the continued safe, reliable, and efficient operation of existing plants has become indispensable. For these plants asset management is an essential factor. A crucial part of the plant assets are the steam generators (SG). Not only that the SG tubes are by far the largest boundary between the primary and secondary sides, they are also instrumental in the overall performance of the plant. The main concern for operational lifetime is tube degradation due to either ID or OD corrosion. At the secondary side, sludge and corrosion products accumulate in the SG resulting in the buildup of secondary side deposits. Such deposits can negatively affect the SG performance in different ways, not only by reduction of the heat transfer rates and, thus, by reducing the efficiency of the SG but also as cause or promotion of different types of corrosion phenomena. The cleanliness of the secondary side of SG is of essential interest to all utilities. There is not just one solution for SG asset optimization. The utilities must weigh the pros and cons of SG cleaning, with the associated impact on outage time and cost, versus the potential benefits. Each plant that considers a SG chemical cleaning has different objectives and goals. AREVA has developed the C 3 (Customized Chemical Cleaning - or in short 'C cubed') concept in order to provide the utility with a chemical cleaning method that is tailored to the needs of the individual units and that addresses them directly. (orig.)

DEVELOPMENT OF AN INSOLUBLE SALT SIMULANT TO SUPPORT ENHANCED CHEMICAL CLEANING TESTS

International Nuclear Information System (INIS)

Eibling, R

2008-01-01

The closure process for high level waste tanks at the Savannah River Site will require dissolution of the crystallized salts that are currently stored in many of the tanks. The insoluble residue from salt dissolution is planned to be removed by an Enhanced Chemical Cleaning (ECC) process. Development of a chemical cleaning process requires an insoluble salt simulant to support evaluation tests of different cleaning methods. The Process Science and Engineering section of SRNL has been asked to develop an insoluble salt simulant for use in testing potential ECC processes (HLE-TTR-2007-017). An insoluble salt simulant has been developed based upon the residues from salt dissolution of saltcake core samples from Tank 28F. The simulant was developed for use in testing SRS waste tank chemical cleaning methods. Based on the results of the simulant development process, the following observations were developed: (1) A composition based on the presence of 10.35 grams oxalate and 4.68 grams carbonate per 100 grams solids produces a sufficiently insoluble solids simulant. (2) Aluminum observed in the solids remaining from actual waste salt dissolution tests is probably precipitated from sodium aluminate due to the low hydroxide content of the saltcake. (3) In-situ generation of aluminum hydroxide (by use of aluminate as the Al source) appears to trap additional salts in the simulant in a manner similar to that expected for actual waste samples. (4) Alternative compositions are possible with higher oxalate levels and lower carbonate levels. (5) The maximum oxalate level is limited by the required Na content of the insoluble solids. (6) Periodic mixing may help to limit crystal growth in this type of salt simulant. (7) Long term storage of an insoluble salt simulant is likely to produce a material that can not be easily removed from the storage container. Production of a relatively fresh simulant is best if pumping the simulant is necessary for testing purposes. The insoluble

Evaluation of EDTA based chemical formulations for the cleaning of monel-400 tubed steam generators

International Nuclear Information System (INIS)

Velmurugan, S.; Rufus, A.L.; Sathyaseelan, V.S.; Kumar, P.S.; Veena, S.N.; Srinivasan, M.P.; Narasimhan, S.V.

1998-01-01

The Steam Generator (SG) is an important component in any nuclear power plant which contributes significantly for the over all performance of the reactor. The failure of SG tubes occurs mainly by corrosion under accelerated conditions caused by fouling. There is continuous ingress of the corrosion products and ionic impurities from the condenser and feed train of the secondary heat transfer system. The corrosion products accumulate in the stagnant areas near the tube sheet, over the tube support plates and in the tube to tube support plate crevices. These accumulated deposits help to concentrate the aggressive impurities and induce a variety of corrosion processes affecting the structural materials and finally leading to failure of the SG tube. Scale forming impurities can deposit over the tube surfaces and result in reduction of heat transfer efficiency and over heating of the surfaces. Every effort is being made to control the transport of impurities to the steam generator. Increased blow down, installation of condensate polishers and use of all volatile amines have helped to reduce the corrosion product and ionic impurities input into the steam generators of PHWRs. Despite these efforts, failures of SG tubes in PHWRs have been reported. Hence, attempts are being made to develop chemical formulations to clean the deposits accumulated in the steam generators. The EPRI-SGOG chemical cleaning process has been tried with good success in steam generators of different designs including the steam generators of PHWRs. This paper discusses the work on the evaluation of EDTA based chemical cleaning formulations for monel-400 tubed steam generators of PHWRs. (author)

Technology for cleaning of Pb-Bi adhering to steel (1). Basic tests

International Nuclear Information System (INIS)

Saito, Shigeru; Sasa, Toshinobu; Umeno, Makoto; Kurata, Yuji; Kikuchi, Kenji; Futakawa, Masatoshi

2004-12-01

The accelerator driven system (ADS) is proposed to transmute minor actinides (MA) in high-level waste from spent fuels of nuclear power reactors. Liquid Pb-Bi alloy is a candidate material for spallation target and coolant of ADS. Pb-Bi cleaning technology is required to reduce radiation exposure during maintenance service and to decontaminate replaced components. In this study, three cleaning methods were tested; silicon oil cleaning at 170degC, mixture of acetic acid and nitric acid cleaning. Specimens were prepared by immersion in melted Pb-Bi. After silicon oil tests, most of Pb-Bi remained on the surface of the specimens. It was found that blushing was needed to remove Pb-Bi effectively. On the other hands, Pb-Bi was easily dissolved and almost removed in the mixed acid and nitric acid. Silicon oil cleaning did not affect on base metals. The surface of base metals was slightly blacked after mixed acid cleaning. F82H base metals were corroded by nitric acid. (author)

Processes of elimination of activated corrosion products. Chemical decontamination - fuel cleaning

International Nuclear Information System (INIS)

Viala, C.; Brun, C.; Neuhaus, R.; Richier, S.; Bachet, M.

2007-01-01

The abatement of the individual and collective dose of a PWR imposes to control the source term through different processes implemented during the plant exploitation. When the limits of these different optimization processes are reached, the abatement of dose rates requires the implementation of curative processes. The objective is thus to eliminate the contaminated oxides and deposits present on surfaces free of radiation flux, and eventually on surfaces under radiation flux and on the fuel itself. The chemical decontamination of equipments and systems is the main and universal remedy implemented at different levels. On the other hand, the ultrasonic cleaning of fuel assemblies is a promising process. This paper aims at illustrating these different techniques using concrete examples of application in France and abroad (decontamination during steam generator replacement, decontamination of primary pump scroll in hot workshop, decontamination of loop sections, ultrasonic cleaning of fuel). The description of these different operations stresses on their efficiency in terms of dosimetric gain, duration of implementation, generation of wastes, and recontamination following their implementation. (J.S.)

Clean Water Act

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — These data represent geographic terms used within the Clean Water Act (CWA). The CWA establishes the basic structure for regulating the addition of pollutants...

Forecasting global developments in the basic chemical industry for environmental policy analysis

NARCIS (Netherlands)

Broeren, M.L.M.|info:eu-repo/dai/nl/371687438; Saygin, D.; Patel, M.K.

The chemical sector is the largest industrial energy user, but detailed analysis of its energy use developments lags behind other energy-intensive sectors. A cost-driven forecasting model for basic chemicals production is developed, accounting for regional production costs, demand growth and stock

Materials and boiler rig testing to support chemical cleaning of once-through AGR boilers

International Nuclear Information System (INIS)

Tice, D.R.; Platts, N.; Raffel, A.S.; Rudge, A.

2002-01-01

An extensive programme of work has been carried out to evaluate two candidate inhibited cleaning solutions for possible implementation on plant, which would be the first chemical clean of an AGR boiler. The two candidate cleaning solutions considered were a Stannine-inhibited citric acid/formic acid mixture (GOM106) and inhibited hydrofluoric acid. Citric acid-based cleaning processes are widely used within the UK Power Industry. The GOM106 solution, comprising a mixture of 3% citric acid, 0.5% formic acid and 0.05% Stannine LTP inhibitor, buffered with ammonia to pH 3.5, was developed specifically for the AGR boilers during the 1970's. Although a considerable amount of materials testing work was carried out by British Energy's predecessor companies to produce a recommended cleaning procedure there were some remaining concerns with the use of GOM106, from these earlier studies, for example, an increased risk of pitting attack associated with the removal of thick 9Cr oxide deposits and a risk of unacceptable damage in critical locations such as the upper transition joints and other weld locations. Hence, additional testing was still required to validate the solution for use on plant. Inhibited hydrofluoric acid (HFA) was also evaluated as an alternative reagent to GOM106. HFA has been used extensively for cleaning mild and low'alloy steel boiler tubes in fossil-fired plant in the UK and elsewhere in Europe and is known to remove oxide quickly. Waste treatment is also easier than for the GOM106 process and some protection against damage to the boiler tube materials is provided by complexing of fluoride with ferric ion. Validation of the potential reagents and inhibitors was achieved by assessing the rate and effectiveness of oxide removal from specimens of helical boiler tubing and welds, together with establishing the extent of any metal loss or localised damage. The initial materials testing resulted in the inhibited ammoniated citric / formic acid reagent being

EM-31 Alternative And Enhanced Chemical Cleaning Program For Sludge Heel Removal - 11220

International Nuclear Information System (INIS)

King, W.; Hay, M.; Wiersma, B.; Pennebaker, F.

2010-01-01

Mixtures of oxalic acid with nitric acid have been shown to be superior to oxalic acid alone for the dissolution of iron-rich High Level Waste sludge heels. Optimized conditions resulting in minimal oxalate usage and stoichiometric iron dissolution (based on added oxalate ion) have been determined for hematite (a primary sludge iron phase) in oxalic/nitric acid mixtures. The acid mixtures performed better than expected based on the solubility of hematite in the individual acids through a synergistic effect in which the preferred 1:1 Fe:oxalate complex is formed. This allows for the minimization of oxalate additions to the waste stream. Carbon steel corrosion rates were measured in oxalic/nitric acid mixtures to evaluate the impacts of chemical cleaning with these solutions on waste tank integrity. Manageable corrosion rates were observed in the concentration ranges of interest for an acid contact timescale of 1 month. Kinetics tests involving hematite and gibbsite (a primary sludge aluminum phase) have confirmed that (ge)90% solids dissolution occurs within 3 weeks. Based on these results, the chemical cleaning conditions recommended to promote minimal oxalate usage and manageable corrosion include: 0.5 wt. % oxalic acid/0.175 M nitric acid mixture, 50 C, 2-3 week contact time with agitation.

Cleaning Services.

Science.gov (United States)

Sharpton, James L.

This curriculum guide provides cleaning services instructional materials for a ninth- and tenth-grade Coordinated Vocational Education and Training: Home and Community Services program. It includes 2 sections and 11 instructional units. Each unit of instruction consists of eight basic components: performance objectives, teacher activities,…

New catalysts for clean environment

Energy Technology Data Exchange (ETDEWEB)

Maijanen, A; Hase, A [eds.; VTT Chemical Technology, Espoo (Finland)

1997-12-31

VTT launched a Research Programme on Chemical Reaction Mechanisms (CREAM) in 1993. The three-year programme (1993-1995) has focused on reaction mechanisms relevant to process industries and aimed at developing novel catalysts and biocatalysts for forest, food, and specialty chemicals industries as well as for energy production. The preliminary results of this programme have already been presented in the first symposium organized in Espoo in September 1994. To conclude the programme the second symposium is organized in Otaniemi, Espoo on January 29 - 30, 1996. Papers by 19 speakers and 17 poster presentations of the 1996 Symposium are included in this book. The Symposium consists of four sessions: Biotechnology for Natural Fibers Processing, New Biocatalysts, Catalysts for Clean Energy, and New Opportunities for Chemical Industry. The CREAM programme has tried to foresee solutions for the problems challenged by the public concern on environmental aspects, especially dealing with industrial processes and novel use of raw materials and energy. The programme has followed the basic routes that can lead to natural and simple solutions to develop processes in the fields of forest, food fine chemicals, and energy industry. This symposium presents the results of the programme to learn and further discuss together with the international experts that have been invited as keynote speakers. (author)

New catalysts for clean environment

Energy Technology Data Exchange (ETDEWEB)

Maijanen, A.; Hase, A. [eds.] [VTT Chemical Technology, Espoo (Finland)

1996-12-31

VTT launched a Research Programme on Chemical Reaction Mechanisms (CREAM) in 1993. The three-year programme (1993-1995) has focused on reaction mechanisms relevant to process industries and aimed at developing novel catalysts and biocatalysts for forest, food, and specialty chemicals industries as well as for energy production. The preliminary results of this programme have already been presented in the first symposium organized in Espoo in September 1994. To conclude the programme the second symposium is organized in Otaniemi, Espoo on January 29 - 30, 1996. Papers by 19 speakers and 17 poster presentations of the 1996 Symposium are included in this book. The Symposium consists of four sessions: Biotechnology for Natural Fibers Processing, New Biocatalysts, Catalysts for Clean Energy, and New Opportunities for Chemical Industry. The CREAM programme has tried to foresee solutions for the problems challenged by the public concern on environmental aspects, especially dealing with industrial processes and novel use of raw materials and energy. The programme has followed the basic routes that can lead to natural and simple solutions to develop processes in the fields of forest, food fine chemicals, and energy industry. This symposium presents the results of the programme to learn and further discuss together with the international experts that have been invited as keynote speakers. (author)

Attitudes toward managing hazardous waste: What should be cleaned up and who should pay for it?

International Nuclear Information System (INIS)

Baron, J.; Kunreuther, H.; Gowda, R.

1993-01-01

Hazardous waste policy in the United States uses a liability-based approach, including strict, retroactive, and joint and several liability. To assess attitudes toward these basic principles of liability, and toward priorities for clean-up of wastes, a questionnaire was mailed to legislators, judges, executives of oil and chemical companies, environmentalists, and economists. The questionnaire consisted of abstract, simplified cases, which contrasted basic principles rather than dealing with real-world scenarios. Subjects were asked how they would allocate clean-up costs between companies and government as a function of such factors as adherence to standards, adoption of best available technology (BAT), and influence of penalties on future behavior. Most subjects felt that, if the company followed government standards or used the best available technology (BAT), it should pay for only a portion of the clean-up cost, with the government paying the rest. In general, responses did not support the principles underlying current law - strict, retroactive, and joint-and-several liability. Most subjects were more interested in polluters paying for damages than in deterrence or future benefit - even to the extent that they would have 'harmless' waste sites cleaned up. A bias was found toward complete clean-up of some sites, or 'zero risk.' Different groups of subjects gave similar answers, although more committed environmentalists were more willing to make companies pay and to clean up waste regardless of the cost. 21 refs., 3 tabs

Substrate Effect on Plasma Clean Efficiency in Plasma Enhanced Chemical Vapor Deposition System

Directory of Open Access Journals (Sweden)

Shiu-Ko JangJian

2007-01-01

Full Text Available The plasma clean in a plasma-enhanced chemical vapor deposition (PECVD system plays an important role to ensure the same chamber condition after numerous film depositions. The periodic and applicable plasma clean in deposition chamber also increases wafer yield due to less defect produced during the deposition process. In this study, the plasma clean rate (PCR of silicon oxide is investigated after the silicon nitride deposited on Cu and silicon oxide substrates by remote plasma system (RPS, respectively. The experimental results show that the PCR drastically decreases with Cu substrate compared to that with silicon oxide substrate after numerous silicon nitride depositions. To understand the substrate effect on PCR, the surface element analysis and bonding configuration are executed by X-ray photoelectron spectroscopy (XPS. The high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS is used to analyze microelement of metal ions on the surface of shower head in the PECVD chamber. According to Cu substrate, the results show that micro Cu ion and the CuOx bonding can be detected on the surface of shower head. The Cu ion contamination might grab the fluorine radicals produced by NF3 ddissociation in the RPS and that induces the drastic decrease on PCR.

Industrial use of coal and clean coal technology

Energy Technology Data Exchange (ETDEWEB)

Leibson, I; Plante, J J.M.

1990-06-01

This report builds upon two reports published in 1988, namely {ital The use of Coal in the Industrial, Commercial, Residential and Transportation Sectors} and {ital Innovative Clean Coal Technology Deployment}, and provides more specific recommendations pertaining to coal use in the US industrial sector. The first chapter addresses industrial boilers which are common to many industrial users. The subsequent nine chapters cover the following: coke, iron and steel industries; aluminium and other metals; glass, brick, ceramic, and gypsum industries; cement and lime industries; pulp and paper industry; food and kindred products; durable goods industry; textile industry; refining and chemical industry. In addition, appendices supporting the contents of the study are provided. Each chapter covers the following topics as applicable: energy overview of the industry sector being discussed; basic processes; foreign experience; impediments to coal use; incentives that could make coal a fuel of choice; current and projected use of clean coal technology; identification of coal technology needs; conclusions; recommendations.

TECHNOLOGY OF REVERSE-BLAST CORROSION CLEANING OF STEEL SHEETS PRIOR TO LASER CUTTING

Directory of Open Access Journals (Sweden)

A. N. Zguk

2017-01-01

Full Text Available Quality of surface cleaning against corrosion influences on efficiency in realization of a number of technological processes. While using bentonite clays in power fluid reverse-blast cleaning ensures formation of anticorrosion protective coating with light absorbing properties on the cleaned surface and prevents formation of the repeated corrosion. The paper presents results of the investigations pertaining to influence of reverse-blast cleaning parameters of steel sheets on quality of the cleaned surface prior to laser cutting. Processing conditions, applied compositions of power fluid and also properties of the protective film coatings on the cleaned surface have been given in the paper. The paper considers topography, morphology and chemical composition of the given coating while applying complex metal micrographic, X-ray diffraction and electronic and microscopic investigations. A complex of laser cutting (refer to gas lasers with output continuous capacity of 2.5/4.0 kW has been applied for experimental works to evaluate influence of the formed surface quality on efficiency of laser cutting process. Specimens having dimension 120×120 mm, made of steel Ст3пс, with thickness from 3 to 10 mm have been prepared for the experiments. An analysis has shown that the application of reverse-blast cleaning ensures higher speed in laser cutting by a mean of 10–20 %. The investigations have made it possible to determine optimum cleaning modes: distance from a nozzle to the surface to be cleaned, jet velocity, pressure. It has been revealed that after drying of the specimens processed by power fluid based on water with concentrations of bentonite clay and calcined soda a protective film coating with thickness of some 5–7 µm has been formed on the whole cleaned specimen surfaces. Chemical base of the coating has been formed by the elements which are included in the composition of bentonite clay being the basic component of the power fluid. 

Standard Test Method for Effects of Cleaning and Chemical Maintenance Materials on Painted Aircraft Surfaces

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This test method covers determination of the effects of cleaning solutions and liquid cleaner concentrates on painted aircraft surfaces (Note 1). Streaking, discoloration, and blistering may be determined visually. Softening is determined with a series of specially prepared pencils wherein determination of the softest pencil to rupture the paint film is made. Note 1—This test method is applicable to any paint film that is exposed to cleaning materials. MIL-PRF-85285 has been selected as a basic example. When other paint finishes are used, refer to the applicable material specification for panel preparation and system curing prior to testing. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user ...

Heat exchanger cleaning

International Nuclear Information System (INIS)

Gatewood, J.R.

1980-01-01

A survey covers the various types of heat-exchange equipment that is cleaned routinely in fossil-fired generating plants, the hydrocarbon-processing industry, pulp and paper mills, and other industries; the various types, sources, and adverse effects of deposits in heat-exchange equipment; some details of the actual procedures for high-pressure water jetting and chemical cleaning of some specific pieces of equipment, including nuclear steam generators. (DN)

Low-temperature wafer direct bonding of silicon and quartz glass by a two-step wet chemical surface cleaning

Science.gov (United States)

Wang, Chenxi; Xu, Jikai; Zeng, Xiaorun; Tian, Yanhong; Wang, Chunqing; Suga, Tadatomo

2018-02-01

We demonstrate a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning. After a post-annealing at 200 °C, strong bonding interfaces with no defects or microcracks were obtained. On the basis of the detailed surface and bonding interface characterizations, the bonding mechanism was explored and discussed. The amino groups terminated on the cleaned surfaces might contribute to the bonding strength enhancement during the annealing. This cost-effective bonding process has great potentials for silicon- and glass-based heterogeneous integrations without requiring a vacuum system.

Importance of deposit information in the design and execution of steam generator chemical cleaning

International Nuclear Information System (INIS)

Flores, O.; Remark, J.

1997-01-01

During the planning stages of the chemical cleaning of the San Onofre Nuclear Generating Station (SONGS) units 2 and 3 steam generators, it was determined that an understanding of the steam generator deposit loading and composition was essential to the design and success of the project. It was also determined that qualification testing, preferably with actual deposits from the SONGS steam generators, was also essential. SONGS units 2 and 3 have Combustion Engineering (CE)-designed pressurized water reactors. Each unit has two CE model 3410 steam generators. Each steam generator has 9350 alloy 600 tubes with 1.9-cm (3/4 in.) outside diameter. Unit 2 began commercial operation in 1983, and unit 3, in 1984. The purpose of this technical paper is to explain the effort and methodology for deposit composition, characterization, and quantification. In addition, the deposit qualification testing and design of the cleaning are discussed

Preventive acid chemical cleaning operation (PACCO) on steam generator in French nuclear power plants

International Nuclear Information System (INIS)

Traino, Jules; Ruiz Martinez, Jose Thomas; Rottner, Bernard; Vedova, Eric

2014-01-01

Steam Generators (SG) usually present important deposit loading and Tube Support Blockage, resulting from Secondary Side corrosion products. These phenomena modify SG behavior which can lead to safety, heat exchange performance and lifetime problems. In this context, a Chemical Cleaning Process (PACCO) was designed to solve the issue. After almost two years of intensive lab tests, pilot simulation and mock-ups, the chemical process was finally qualified by EDF. The aim of the work was firstly the development in laboratory of a chemical process that could eliminate partially the deposit loading, respecting the integrity of materials and gas emission limits. Secondly, the objective was the design and the implementation of the process on-site. The process has been applied successfully in 3 SG in Dampierre nuclear power plant in France on July 2013. The main results were: - Corrosion < 100 μm. - 40% of the initial deposit loading, removed by SG. (authors)

Late washing filter cleaning cycle demonstration

International Nuclear Information System (INIS)

Meyer, M.L.; McCabe, D.J.

1992-01-01

The DWPF Late Washing Facility will filter cesium and potassium tetraphenyl borate (TPB) solids using a Mott sintered metal filter, identical to the filter now used in the In-tank Precipitation Facility. The purpose of the late wash step is primarily to remove the nitrite salts from the slurry prior to delivery to DWPF. Periodic chemical cleaning of the filter will be required, presumably after each batch although the actual required frequency could not be determined on the lab-scale. Minimization of chemical cleaning solution volumes is key to maximizing the attainment of the Late Wash facility. This report summarizes work completed in experiments designed to identify minimum cleaning solution requirements

Keeping condensers clean

Energy Technology Data Exchange (ETDEWEB)

Wicker, K.

2006-04-15

The humble condenser is among the biggest contributors to a steam power plant's efficiency. But although a clean condenser can provide great economic benefit, a dirty one can raise plant heat rate, resulting in large losses of generation revenue and/or unnecessarily high fuel bills. Conventional methods for cleaning fouled tubes range form chemicals to scrapers to brushes and hydro-blasters. This article compares the available options and describes how one power station, Omaha Public Power District's 600 MW North Omaha coal-fired power station, cleaned up its act. The makeup and cooling water of all its five units comes from the Missouri River. 6 figs.

Noncontact COS charge analysis for in-line monitoring of wet cleaning processes

Science.gov (United States)

Zhang, Xiafang; Juang, Min; Tai, Sung-Shan; Chen, Kuo-in; Wossen, Ejigu; Horner, Gregory

1998-08-01

Contamination levels in chemical cleaning equipment and wafer cleanliness in general are very critical to semiconductor manufacturers. In this work, a Keithley Instruments non contact electrical tester (Quantox) is used to measure the mobile ion (Qm) contamination in a variety of cleaning processes. Results show that photoresist strip cleaning process has a higher mobile ion concentration than standard pre-diffusion cleaning process. RCA1, RCA2 and HF solutions mapping measured by the Quantox indicates some negative static charges on the surface after cleaning. This negative field appears to assist Qm removal during wet chemical cleaning. The dependence of flatband voltage and other oxide charges on various cleaning processes has also been investigated using the Quantox. The data suggests that a dipole layer has been formed by a surface reaction during chemical cleaning.

Clean coal technologies

International Nuclear Information System (INIS)

Aslanyan, G.S.

1993-01-01

According to the World Energy Council (WEC), at the beginning of the next century three main energy sources - coal, nuclear power and oil will have equal share in the world's total energy supply. This forecast is also valid for the USSR which possesses more than 40% of the world's coal resources and continuously increases its coal production (more than 700 million tons of coal are processed annually in the USSR). The stringent environmental regulations, coupled with the tendency to increase the use of coal are the reasons for developing different concepts for clean coal utilization. In this paper, the potential efficiency and environmental performance of different clean coal production cycles are considered, including technologies for coal clean-up at the pre-combustion stage, advanced clean combustion methods and flue gas cleaning systems. Integrated systems, such as combined gas-steam cycle and the pressurized fluidized bed boiler combined cycle, are also discussed. The Soviet National R and D program is studying new methods for coal utilization with high environmental performance. In this context, some basic research activities in the field of clean coal technology in the USSR are considered. Development of an efficient vortex combustor, a pressurized fluidized bed gasifier, advanced gas cleaning methods based on E-beam irradiation and plasma discharge, as well as new catalytic system, are are presented. In addition, implementation of technological innovations for retrofitting and re powering of existing power plants is discussed. (author)

Generation of dissolved organic matter and byproducts from activated sludge during contact with sodium hypochlorite and its implications to on-line chemical cleaning in MBR.

Science.gov (United States)

Cai, Weiwei; Liu, Jiaqi; Zhang, Xiangru; Ng, Wun Jern; Liu, Yu

2016-11-01

On-line chemical cleaning of membranes with sodium hypochlorite (NaClO) has been commonly employed for maintaining a constant permeability of membrane bioreactor (MBR) due to its simple and efficient operation. However, activated sludge is inevitably exposed to NaClO during this cleaning process. In spite of the broad applications of on-line chemical cleaning in MBR such as chemical cleaning-in-place (CIP) and chemical enhanced backwash (CEB), little information is currently available for the release of emerging dissolved organic matter (DOM) and byproducts from this prevalent practice. Therefore, in this study, activated sludge suspended in a phosphate buffered saline solution was exposed to different doses of NaClO in order to determine the generation of potential DOM and byproducts. The results showed the occurrence of significant DOM release (up to 24.7 mg/L as dissolved organic carbon) after exposure to NaClO for 30 min. The dominant components of the released DOM were characterized to be humic acid-like as well as protein-like substances by using an excitation-emission matrix fluorescence spectrophotometer. Furthermore, after the contact of activated sludge with NaClO, 19 kinds of chlorinated and brominated byproducts were identified by ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, eight of which were confirmed and characterized with standard compounds. Many byproducts were found to be halogenated aromatic compounds, including halopyrroles and halo(hydro)benzoquinones, which had been reported to be significantly more toxic than the halogenated aliphatic ones. Consequently, this study offers new insights into the practice of on-line chemical cleaning, and opens up a window to re-examine the current operation of MBR by looking into the generation of micropollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Flue gas cleaning chemistry

Energy Technology Data Exchange (ETDEWEB)

Gutberlet, H [VEBA Kraftwerke Ruhr AG, Gelsenkirchen (Germany)

1996-12-01

The introduction of modern flue gas cleaning technology into fossil-fueled power stations has repeatedly confronted the power station chemists with new and interesting problems over the last 15 - 20 years. Both flue gas desulphurization by lime washing and catalytic removal of nitrogen oxides are based on simple basic chemical reactions. Owing to the use of readily available starting materials, the production of safe, useful end products and, last but not least, the possibility of implementing all this on an industrial scale by means of efficient process engineering, limestone desulphurization and catalytic removal of nitrogen oxides dominate the world market and, little by little, are becoming still more widespread. The origin and thus the quality of fuels and starting materials, the firing method, the mode of operation and engineering peculiarities in each plant interact in a complex manner. Simple cause/effect relationships are frequently incapable of explaining phenomena; thinking in complex interrelationships is needed. (EG)

太阳能硅料化学清洗研究进展%Development of chemical cleaning for solar energy silicon material

Institute of Scientific and Technical Information of China (English)

申燕; 贾艳飞; 姚旭; 张健; 廉佳林

2016-01-01

Silicon as the main material of solar photovoltaic power generation in the solar photovoltaic industry, the demand for silicon material cleanliness also gradualy increases under the background of the rapid development of the market. Chemical cleaning is the main method of silicon material cleaning. In this paper, the research progress of the standard cleaning method ( RCA ) and depending on the silicon material by RCA method to develop other chemical cleaning method was reviewed.%多晶硅作为太阳能光伏发电的主要材料，在太阳能光伏产业市场迅速发展的大背景下，对硅料清洁度的需求也逐步增加。化学清洗是目前硅料清洗的主要方法。本文综述了近年来硅料化学清洗的基本方法（RCA）及根据硅料的不同由RCA法发展出的其他化学清洗方法。

Significant OH production under surface cleaning and air cleaning conditions: Impact on indoor air quality.

Science.gov (United States)

Carslaw, N; Fletcher, L; Heard, D; Ingham, T; Walker, H

2017-11-01

We report measurements of hydroxyl (OH) and hydroperoxy (HO 2 ) radicals made by laser-induced fluorescence spectroscopy in a computer classroom (i) in the absence of indoor activities (ii) during desk cleaning with a limonene-containing cleaner (iii) during operation of a commercially available "air cleaning" device. In the unmanipulated environment, the one-minute averaged OH concentration remained close to or below the limit of detection (6.5×10 5  molecule cm -3 ), whilst that of HO 2 was 1.3×10 7  molecule cm -3 . These concentrations increased to ~4×10 6 and 4×10 8  molecule cm -3 , respectively during desk cleaning. During operation of the air cleaning device, OH and HO 2 concentrations reached ~2×10 7 and ~6×10 8  molecule cm -3 respectively. The potential of these OH concentrations to initiate chemical processing is explored using a detailed chemical model for indoor air (the INDCM). The model can reproduce the measured OH and HO 2 concentrations to within 50% and often within a few % and demonstrates that the resulting secondary chemistry varies with the cleaning activity. Whilst terpene reaction products dominate the product composition following surface cleaning, those from aromatics and other VOCs are much more important during the use of the air cleaning device. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Emerging forward osmosis (FO) technologies and challenges ahead for clean water and clean energy applications

KAUST Repository

Chung, Tai-Shung; Li, Xue; Ong, Rui Chin; Ge, Qingchun; Wang, Honglei; Han, Gang

2012-01-01

The purpose of this short review is to share our understanding and perspectives with the chemical, environmental, water and osmotic power communities on FO processes in order to conduct meaningful R & D and develop effective and sustainable FO technologies for clean water and clean energy. © 2012 Elsevier Ltd. All rights reserved.

Emerging forward osmosis (FO) technologies and challenges ahead for clean water and clean energy applications

KAUST Repository

Chung, Tai-Shung

2012-08-01

The purpose of this short review is to share our understanding and perspectives with the chemical, environmental, water and osmotic power communities on FO processes in order to conduct meaningful R & D and develop effective and sustainable FO technologies for clean water and clean energy. © 2012 Elsevier Ltd. All rights reserved.

Investigation of the Pulsed Annular Gas Jet for Chemical Reactor Cleaning

Directory of Open Access Journals (Sweden)

Zvegintsev Valery Ivanovich

2012-01-01

Full Text Available The most economical technology for production of titanium dioxide pigment is plasma-chemical syntheses with the heating of the oxygen. The highlight of the given reaction is formation of a solid phase as a result of interactions between two gases, thus brings the formation of particle deposits on the reactor walls, and to disturbing the normal operation of the technological process. For the solving of the task of reactor internal walls cleaning the pulsed gaseous system was suggested and investigated, which throws circular oxygen jet along surfaces through regular intervals. Study of aerodynamic efficiency of the impulse system was carried by numerical modeling and experimentally with the help of a specially created experimental facility. The distribution of the pulsed flow velocity at the exit of cylindrical reactor was measured. The experimental results have shown that used impulse device creates a pulsed jet with high value of the specified flow rate. It allows to get high velocities that are sufficient for the particle deposits destruction and their removal away. Designed pulsed peelings system has shown high efficiency and reliability in functioning that allows us to recommend it for wide spreading in chemical industry.

Clean conditions during the erection phase

International Nuclear Information System (INIS)

Koschel, P.

1977-01-01

Following the basic requirements of the Regulatory Guide 1.37 and ANSI 45.2.1 - Standard on Cleaning of Fluid Systems and Associated Components during the Construction Phase of Nuclear Power Plants as a guideline, the implementation of cleaning operations in the pre-installation phase, the installation phase and the maintenance of clean conditions until the operational phase is covered. Specific information will be given from the practical experience point of view with the work execution under clean conditions of piping and components at the semi-finished product manufacturer, the prefabrication workshop and the on-site installation with specific reference to the various detailed procedures required by individual system builders for nuclear power plants in Germany and abroad. (orig.) [de

Commercial Cleaning Products for Chemical Decontamination: A Scoping Study

Science.gov (United States)

2014-05-01

and may injure human skin without dilution), although this approach is less favoured in a mass casualty decontamination situation than soap and water...commercial cleaning products, full strength K-O-K® liquid bleach (5.25% aqueous solution of NaOCl), dish-washing detergent Cascade® with Extra...Bleach Action Gel, OxiClean® Versatile Stain Remover Powder, and ZEP® Industrial Purple liquid cleaner (proprietary caustic cleaner containing

Discussion on cleaning and maintenance of YA system reverse osmosis membrane

International Nuclear Information System (INIS)

Zhu Yidong

2012-01-01

According to the overproof of pollution data of YA system reverse osmosis membrane in extension project, the daily maintenance company is using chemical cleaning on reverse osmosis unit to eliminate the pollution blindly, the fixed prescription, fixed dosage and high frequency of the chemical cleaning. The writer analyzed the cause of the membrane pollution and commended several chemical cleaning methods by the long-period study of the system, and also some suggestion, according to the status of operational site, for the daily maintenance. (author)

Benzotriazole removal on post-Cu CMP cleaning

International Nuclear Information System (INIS)

Tang Jiying; Liu Yuling; Sun Ming; Fan Shiyan; Li Yan

2015-01-01

This work investigates systematically the effect of FA/O II chelating agent and FA/O I surfactant in alkaline cleaning solutions on benzotriazole (BTA) removal during post-Cu CMP cleaning in GLSI under the condition of static etching. The best detergent formulation for BTA removal can be determined by optimization of the experiments of single factor and compound cleaning solution, which has been further confirmed experimentally by contact angle (CA) measurements. The resulting solution with the best formulation has been measured for the actual production line, and the results demonstrate that the obtained cleaning solution can effectively and efficiently remove BTA, CuO and abrasive SiO 2 without basically causing interfacial corrosion. This work demonstrates the possibility of developing a simple, low-cost and environmentally-friendly cleaning solution to effectively solve the issues of BTA removal on post-Cu CMP cleaning in a multi-layered copper wafer. (paper)

Update-processing steam generator cleaning solvent at Palo Verde

International Nuclear Information System (INIS)

Peters, G.

1996-01-01

Framatome Technologies Inc.(FTI) recently completed the steam generator chemical cleanings at the Palo Verde Nuclear Generating Station Units 1, 2 and 3. Over 500,000 gallons of low-level radioactive solvents were generated during these cleanings and were processed on-site. Chemical cleaning solutions containing high concentrations of organic chelating wastes are difficult to reduce in volume using standard technologies. The process that was ultimately used at Palo Verde involved three distinct processing steps: The evaporation step was conducted using FTI's submerged combustion evaporator (SCE) that has also been successfully used at Arkansas Nuclear One - Unit 1, Three Mile Island - Unit 1, and Oconee on similar waste. The polishing step of the distillate used ultrafiltration (UF) and reverse osmosis (RO) technology that was also used extensively by Ontario Hydro to assist in their processing of chemical cleaning solvent. This technology, equipment, and operations personnel were provided by Zenon Environmental, Inc. The concentrate from the evaporator was absorbed with a special open-quotes peat mossclose quotes based media that allowed it to be shipped and buried at the Environcare of Utah facility. This is the first time that this absorption media or burial site has been used for chemical cleaning solvent

Ethanol Basics

Energy Technology Data Exchange (ETDEWEB)

None

2015-01-30

Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

Permeability recovery of fouled forward osmosis membranes by chemical cleaning during a long-term operation of anaerobic osmotic membrane bioreactors treating low-strength wastewater.

Science.gov (United States)

Wang, Xinhua; Hu, Taozhan; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

2017-10-15

Anaerobic osmotic membrane bioreactor (AnOMBR) has gained increasing interests in wastewater treatment owing to its simultaneous recovery of biogas and water. However, the forward osmosis (FO) membrane fouling was severe during a long-term operation of AnOMBRs. Here, we aim to recover the permeability of fouled FO membranes by chemical cleaning. Specifically speaking, an optimal chemical cleaning procedure was searched for fouled thin film composite polyamide FO (TFC-FO) membranes in a novel microfiltration (MF) assisted AnOMBR (AnMF-OMBR). The results indicated that citric acid, disodium ethylenediaminetetraacetate (EDTA-2Na), hydrochloric acid (HCl), sodium dodecyl sulfate (SDS) and sodium hydroxide (NaOH) had a low cleaning efficiency of less than 15%, while hydrogen peroxide (H 2 O 2 ) could effectively remove foulants from the TFC-FO membrane surface (almost 100%) through oxidizing the functional group of the organic foulants and disintegrating the colloids and microbe flocs into fine particles. Nevertheless, the damage of H 2 O 2 to the TFC-FO membrane was observed when a high cleaning concentration and a long duration were applied. In this case, the optimal cleaning conditions including cleaning concentration and time for fouled TFC-FO membranes were selected through confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM) images and the flux recovery rate. The results suggested that the optimal cleaning procedure for fouled TFC-FO membranes was use of 0.5% H 2 O 2 at 25 °C for 6 h, and after that, the cleaned TFC-FO membrane had the same performance as a virgin one including water flux and rejection for organic matters and phosphorus during the operation of AnMF-OMBR. Copyright © 2017 Elsevier Ltd. All rights reserved.

Benzotriazole removal on post-Cu CMP cleaning

Science.gov (United States)

Jiying, Tang; Yuling, Liu; Ming, Sun; Shiyan, Fan; Yan, Li

2015-06-01

This work investigates systematically the effect of FA/O II chelating agent and FA/O I surfactant in alkaline cleaning solutions on benzotriazole (BTA) removal during post-Cu CMP cleaning in GLSI under the condition of static etching. The best detergent formulation for BTA removal can be determined by optimization of the experiments of single factor and compound cleaning solution, which has been further confirmed experimentally by contact angle (CA) measurements. The resulting solution with the best formulation has been measured for the actual production line, and the results demonstrate that the obtained cleaning solution can effectively and efficiently remove BTA, CuO and abrasive SiO2 without basically causing interfacial corrosion. This work demonstrates the possibility of developing a simple, low-cost and environmentally-friendly cleaning solution to effectively solve the issues of BTA removal on post-Cu CMP cleaning in a multi-layered copper wafer. Project supported by the Major National Science and Technology Special Projects (No. 2009ZX02308).

EDF feedback on recent EPRI SGOG SG chemical cleanings applications for TSP blockage reduction and heat transfer recover

International Nuclear Information System (INIS)

Dijoux, M.; De Bouvier, O.; Mercier, S.; Pages, D.; Bretelle, J.-L.; Leclercq, P.; Mermillod, A.

2010-01-01

Between 2007 and 2008, six Steam Generators Chemical Cleanings (SGCC) with the inhibitor free high temperature process were applied on EDF PWR units. The main goal was to reduce the excessive Tube Support Plate blockages observed on several units of the EDF fleet and the consequences on wide range levels and the risk of tube cracks. The heat transfer recovery was the second objective. Despite the correct results obtained, the corrosion impact of the high temperature process on internal metallic surfaces, higher than expected, and the environmental issues led EDF to move to a new cleaning process. The low temperature process developed by EPRI SGOG and applied for many years was selected for the same purpose. Some qualification laboratory tests were performed by Dominion Engineering Inc (DEI) to demonstrate the innocuousness an the efficiency of the process to achieve these goals. The EPRI SGOG process was then applied seven times by Westinghouse on the EDF units Cruas 3, Cruas 2, Belleville 1, Cattenom 1, Cattenom 3, Chinon B3 and Cattenom 4 between 2008 and 2010. All these units operate from the initial start at low AVT pH 25 o C (9,2) in the secondary circuit. Due to copper presence in the deposits to remove, the cleaning sequence 'Copper - Iron - Copper steps' was performed each time. After a short description of the process, including the specific adaptation in France, lessons learned are reported in this paper in the following areas: process monitoring, corrosion, efficiency, liquid and gaseous wastes, chemical pollution during start-up. Based on the 3 first applications in 2008, some modifications of the process were implemented, particularly for the copper step. For the units cleaned, 1100 to 4500 kg of deposits per SG have been removed, including TS sludge lancing. The reduction of TSP blockages was satisfying. The effect on steam pressure improvement and the wide range level is then discussed. The paper concludes on EDF perspectives for soft

40 CFR 262.213 - Laboratory clean-outs.

Science.gov (United States)

2010-07-01

... eligible academic entity is not required to count a hazardous waste that is an unused commercial chemical..., subpart C) generated solely during the laboratory clean-out toward its hazardous waste generator status... out, the date the laboratory clean-out begins and ends, and the volume of hazardous waste generated...

Extending CO2 cryogenic aerosol cleaning for advanced optical and EUV mask cleaning

Science.gov (United States)

Varghese, Ivin; Bowers, Charles W.; Balooch, Mehdi

2011-11-01

Cryogenic CO2 aerosol cleaning being a dry, chemically-inert and residue-free process is used in the production of optical lithography masks. It is an attractive cleaning option for the mask industry to achieve the requirement for removal of all printable soft defects and repair debris down to the 50nm printability specification. In the technique, CO2 clusters are formed by sudden expansion of liquid from high to almost atmospheric pressure through an optimally designed nozzle orifice. They are then directed on to the soft defects or debris for momentum transfer and subsequent damage free removal from the mask substrate. Unlike aggressive acid based wet cleaning, there is no degradation of the mask after processing with CO2, i.e., no critical dimension (CD) change, no transmission/phase losses, or chemical residue that leads to haze formation. Therefore no restriction on number of cleaning cycles is required to be imposed, unlike other cleaning methods. CO2 aerosol cleaning has been implemented for several years as full mask final clean in production environments at several state of the art mask shops. Over the last two years our group reported successful removal of all soft defects without damage to the fragile SRAF features, zero adders (from the cleaning and handling mechanisms) down to a 50nm printability specification. In addition, CO2 aerosol cleaning is being utilized to remove debris from Post-RAVE repair of hard defects in order to achieve the goal of no printable defects. It is expected that CO2 aerosol cleaning can be extended to extreme ultraviolet (EUV) masks. In this paper, we report advances being made in nozzle design qualification for optimum snow properties (size, velocity and flux) using Phase Doppler Anemometry (PDA) technique. In addition the two new areas of focus for CO2 aerosol cleaning i.e. pellicle glue residue removal on optical masks, and ruthenium (Ru) film on EUV masks are presented. Usually, the residue left over after the pellicle

Taking into account chemical safety for French basic nuclear installations

International Nuclear Information System (INIS)

Tabard, Laurence; Conte, Dorothee

2013-01-01

Among nuclear installations, some fuel cycle facilities present a high level of chemical hazards. In France, the TSN law of the 13 June 2006 requires taking into account all the risks generated by a basic nuclear installation (BNI). But, as most of the implementing regulatory texts are under development at this time, part of the previous regulation settled down in the 1990's is still applying: the order of the 31 December 1999 concerning technical regulation in order to prevent and to limit hazards generated by nuclear facilities; the decree of the 4 May 1995 and the order of the 26 November 1999 that deal with BNI discharges. Moreover, some parts of BNI or of nuclear sites can be submitted to the general regulation concerning chemical hazards, which is part of the environment code. As a result, even if the TSN law and its implementing decree Nr 2007-1557 of the 2 November 2007 settle clearly that safety of BNI is not only radiological, but must take into account chemical hazards, the latter aspects are still under development. Moreover the application of the existing regulation, even if complex, has helped to assess chemical risks inside BNI and nuclear sites. (authors)

An efficient, environmentally acceptable, clean up system for well completions

International Nuclear Information System (INIS)

Berg, Oe.; Saasen, A.

1996-01-01

Evaluation of different casing cleaning fluid systems has been a difficult task due to the lack of a standardised laboratory measurement technique for technical performance. In order to meet the need for a reliable evaluation of different chemicals and fluid systems used in casing cleaning, a laboratory procedure for the evaluation of casing cleaning chemicals has been developed. This procedure has been successfully applied in the development of a new environmentally acceptable casing cleaning fluid system. Two different procedures are presented. An old method where the drilling fluid was displaced down the annulus and up the drill string was found to be ineffective compared to a method where the drilling fluid was displaced up in the annulus. The application of this procedure together with the use of the new chemical additive has reduced the cost of casing cleanup operations in the range of 30-40%. 10 refs., 1 fig., 4 tabs

TESTING OF ENHANCED CHEMICAL CLEANING OF SRS ACTUAL WASTE TANK 5F AND TANK 12H SLUDGES

Energy Technology Data Exchange (ETDEWEB)

Martino, C.; King, W.

2011-08-22

Forty three of the High Level Waste (HLW) tanks at the Savannah River Site (SRS) have internal structures that hinder removal of the last approximately five thousand gallons of waste sludge solely by mechanical means. Chemical cleaning can be utilized to dissolve the sludge heel with oxalic acid (OA) and pump the material to a separate waste tank in preparation for final disposition. This dissolved sludge material is pH adjusted downstream of the dissolution process, precipitating the sludge components along with sodium oxalate solids. The large quantities of sodium oxalate and other metal oxalates formed impact downstream processes by requiring additional washing during sludge batch preparation and increase the amount of material that must be processed in the tank farm evaporator systems and the Saltstone Processing Facility. Enhanced Chemical Cleaning (ECC) was identified as a potential method for greatly reducing the impact of oxalate additions to the SRS Tank Farms without adding additional components to the waste that would extend processing or increase waste form volumes. In support of Savannah River Site (SRS) tank closure efforts, the Savannah River National Laboratory (SRNL) conducted Real Waste Testing (RWT) to evaluate an alternative to the baseline 8 wt. % OA chemical cleaning technology for tank sludge heel removal. The baseline OA technology results in the addition of significant volumes of oxalate salts to the SRS tank farm and there is insufficient space to accommodate the neutralized streams resulting from the treatment of the multiple remaining waste tanks requiring closure. ECC is a promising alternative to bulk OA cleaning, which utilizes a more dilute OA (nominally 2 wt. % at a pH of around 2) and an oxalate destruction technology. The technology is being adapted by AREVA from their decontamination technology for Nuclear Power Plant secondary side scale removal. This report contains results from the SRNL small scale testing of the ECC process

Decreasing Beam Auto Tuning Interruption Events with In-Situ Chemical Cleaning on Axcelis GSD

International Nuclear Information System (INIS)

Fuchs, Dieter; Spreitzer, Stefan; Vogl, Josef; Bishop, Steve; Eldridge, David; Kaim, Robert

2008-01-01

Ion beam auto tuning time and success rate are often major factors in the utilization and productivity of ion implanters. Tuning software frequently fails to meet specified setup times or recipe parameters, causing production stoppages and requiring manual intervention. Build-up of conductive deposits in the arc chamber and extraction gap can be one of the main causes of auto tuning problems. The deposits cause glitching and ion beam instabilities, which lead to errors in the software optimization routines. Infineon Regensburg has been testing use of XeF 2 , an in-situ chemical cleaning reagent, with positive results in reducing auto tuning interruption events.

Cleaning UF membranes with simple and formulated solutions

NARCIS (Netherlands)

Levitsky, I.; Duek, A.; Naim, R.; Arkhangelsky, E.; Gitis, V.

2012-01-01

The ultrafiltration membranes fouled by proteins are typically cleaned by consecutive soaking in alkali, surfactant and oxidizing solutions. We combined all three chemicals into a formulated cleaning agent and examined its efficiency to restore the water flux without damaging the membrane or

Optimized high temperature oxidation and cleaning at Bugey 3

International Nuclear Information System (INIS)

Ranchoux, Gilles; Wintergerst, Matthieu; Bachet, Martin; Leclercq, Stephanie; Duron, Jean-Daniel; Meunier, Jean-Pierre; Blond, Serge; Dacquait Frederic

2012-09-01

As a part of the EDF Source Term Reduction project, an experimental procedure was carried out at Bugey 3 further to the steam generator replacement. This innovative procedure consists in theory in two complementary phases /1/: - Phase 1: a SG tubes optimized oxidation performed during pre-critical hot functional tests (basic and reducing chemistry) aims to generate an as protective as possible inner oxide layer allowing to reduce the later nickel release, - Phase 2: a cleaning procedure of the primary circuit performed under acid and reducing chemical conditioning at 170 deg. C intends to dissolve and eliminate the outer oxide layer by a simultaneous purification. The objective of such a procedure is to reduce corrosion products inventory (mainly nickel) generated by the first SG tube oxidation during hot functional tests and first operation months by carrying out an appropriate cleaning procedure. Gains were expected not only on RCS and auxiliary systems contamination, dose rates and thus collective dose but also on next outages duration. The objective of this paper is to describe the process implementation at Bugey 3: effective procedure put in place, monitoring program (chemistry and dose rate measurements, EMECC campaign) and firsts results. (authors)

Results of the secondary side chemical cleaning of the steam generators

International Nuclear Information System (INIS)

Doma, A.; Patek, G.

2001-01-01

A significant amount of deposit has developed on the secondary side of the heat transfer tubes of the steam generators (SG) of the Paks Nuclear Power Plant units in course of the years. More than 99.5% of the deposit is made up of magnetite (Fe 3 O 4 ) generated in the secondary circuit of the power plant. Those deposits lead to the decrease of the heat transfer. Even more important is its role from the point of view of operational reliability of the steam generators, leak tightness between the primary and secondary sides. The first series of cleaning took place following 8-9 years of operation of the units. Following the first cleaning cycle the transport of the corrosion products into the steam generators did not change, and thus obviously new cleaning was required. Periodical cleaning of the steam generators shall be assured. (R.P.)

Characterization and electrolytic cleaning of poly(methyl methacrylate) residues on transferred chemical vapor deposited graphene

Science.gov (United States)

Sun, Jianbo; Finklea, Harry O.; Liu, Yuxin

2017-03-01

Poly(methyl methacrylate) (PMMA) residue has long been a critical challenge for practical applications of the transferred chemical vapor deposited (CVD) graphene. Thermal annealing is empirically used for the removal of the PMMA residue; however experiments imply that there are still small amounts of residues left after thermal annealing which are hard to remove with conventional methods. In this paper, the thermal degradation of the PMMA residue upon annealing was studied by Raman spectroscopy. The study reveals that post-annealing residues are generated by the elimination of methoxycarbonyl side chains in PMMA and are believed to be absorbed on graphene via the π-π interaction between the conjugated unsaturated carbon segments and graphene. The post-annealing residues are difficult to remove by further annealing in a non-oxidative atmosphere due to their thermal and chemical stability. An electrolytic cleaning method was shown to be effective in removing these post-annealing residues while preserving the underlying graphene lattice based on Raman spectroscopy and atomic force microscopy studies. Additionally, a solution-gated field effect transistor was used to study the transport properties of the transferred CVD graphene before thermal annealing, after thermal annealing, and after electrolytic cleaning, respectively. The results show that the carrier mobility was significantly improved, and that the p-doping was reduced by removing PMMA residues and post-annealing residues. These studies provide a more in-depth understanding on the thermal annealing process for the removal of the PMMA residues from transferred CVD graphene and a new approach to remove the post-annealing residues, resulting in a residue-free graphene.

Electrochemical cleaning of Sv-08G2S wire surface

International Nuclear Information System (INIS)

Kozlov, E.I.; Degtyarev, V.G.; Novikov, M.P.

1981-01-01

Results of industrial tests of the Sv-08G2S wire with different state of surface fwith technological lubrication, after mechanical cleaning, with electrochemically cleaned surface) are presented. Advantages of welding-technological properties of the wire with electroe chemically cleaned surface are shown. An operation principle of the electrochemical cleaning facility is described. A brief specf ification f of the facility is given [ru

Moderator clean-up system in a heavy water reactor

International Nuclear Information System (INIS)

Sasada, Yasuhiro; Hamamura, Kenji.

1983-01-01

Purpose: To decrease the fluctuation of the poison concentration in heavy water moderator due to a heavy water clean-up system. Constitution: To a calandria tank filled with heavy water as poison-containing moderators, are connected both end of a pipeway through which heavy water flows and to which a clean-up device is provided. Strongly basic resin is filled within the clean-up device and a cooler is disposed to a pipeway at the upstream of the clean-up device. In this structure, the temperature of heavy water at the inlet of the clean-up device at a constant level between the temperature at the exit of the cooler and the lowest temperature for the moderator to thereby decrease the fluctuation in the poison concentration in the heavy water moderator due to the heavy water clean-up device. (Moriyama, K.)

Long-term energy efficiency analysis requires solid energy statistics: The case of the German basic chemical industry

International Nuclear Information System (INIS)

Saygin, D.; Worrell, E.; Tam, C.; Trudeau, N.; Gielen, D.J.; Weiss, M.; Patel, M.K.

2012-01-01

Analyzing the chemical industry’s energy use is challenging because of the sector’s complexity and the prevailing uncertainty in energy use and production data. We develop an advanced bottom-up model (PIE-Plus) which encompasses the energy use of the 139 most important chemical processes. We apply this model in a case study to analyze the German basic chemical industry’s energy use and energy efficiency improvements in the period between 1995 and 2008. We compare our results with data from the German Energy Balances and with data published by the International Energy Agency (IEA). We find that our model covers 88% of the basic chemical industry’s total final energy use (including non-energy use) as reported in the German Energy Balances. The observed energy efficiency improvements range between 2.2 and 3.5% per year, i.e., they are on the higher side of the values typically reported in literature. Our results point to uncertainties in the basic chemical industry’s final energy use as reported in the energy statistics and the specific energy consumption values. More efforts are required to improve the quality of the national and international energy statistics to make them useable for reliable monitoring of energy efficiency improvements of the chemical industry. -- Highlights: ► An advanced model was developed to estimate German chemical industry’s energy use. ► For the base year (2000), model covers 88% of the sector’s total final energy use. ► Sector’s energy efficiency improved between 2.2 and 3.5%/yr between 1995 and 2008. ► Improved energy statistics are required for accurate monitoring of improvements.

Cleaning products and air fresheners: exposure to primary and secondary air pollutants

DEFF Research Database (Denmark)

Nazaroff, W.; Weschler, Charles J.

2004-01-01

Building occupants, including cleaning personnel, are exposed to a wide variety of airborne chemicals when cleaning agents and air fresheners are used in buildings. Certain of these chemicals are listed by the state of California as toxic air contaminants (TACs) and a subset of these are regulated...... by the US federal government as hazardous air pollutants (HAPs). California's Proposition 65 list of species recognized as carcinogens or reproductive toxicants also includes constituents of certain cleaning products and air fresheners. In addition, many cleaning agents and air fresheners contain chemicals...... that can react with other air contaminants to yield potentially harmful secondary products. For example, terpenes can react rapidly with ozone in indoor air generating many secondary pollutants, including TACs such as formaldehyde. Furthermore, ozone-terpene reactions produce the hydroxyl radical, which...

Raman enhancement on ultra-clean graphene quantum dots produced by quasi-equilibrium plasma-enhanced chemical vapor deposition.

Science.gov (United States)

Liu, Donghua; Chen, Xiaosong; Hu, Yibin; Sun, Tai; Song, Zhibo; Zheng, Yujie; Cao, Yongbin; Cai, Zhi; Cao, Min; Peng, Lan; Huang, Yuli; Du, Lei; Yang, Wuli; Chen, Gang; Wei, Dapeng; Wee, Andrew Thye Shen; Wei, Dacheng

2018-01-15

Graphene is regarded as a potential surface-enhanced Raman spectroscopy (SERS) substrate. However, the application of graphene quantum dots (GQDs) has had limited success due to material quality. Here, we develop a quasi-equilibrium plasma-enhanced chemical vapor deposition method to produce high-quality ultra-clean GQDs with sizes down to 2 nm directly on SiO 2 /Si, which are used as SERS substrates. The enhancement factor, which depends on the GQD size, is higher than conventional graphene sheets with sensitivity down to 1 × 10 -9  mol L -1 rhodamine. This is attributed to the high-quality GQDs with atomically clean surfaces and large number of edges, as well as the enhanced charge transfer between molecules and GQDs with appropriate diameters due to the existence of Van Hove singularities in the electronic density of states. This work demonstrates a sensitive SERS substrate, and is valuable for applications of GQDs in graphene-based photonics and optoelectronics.

Clean utilization of coal

International Nuclear Information System (INIS)

Yueruem, Y.

1992-01-01

This volume contains 23 lectures presented at the Advanced Study Institute on 'Chemistry and Chemical Engineering of Catalytic Solid Fuel Conversion for the Production of Clean Synthetic Fuels', which was held at Akcay, Edremit, Turkey, between 21 July and August 3, 1991. Three main subjects: structure and reactivity of coal; cleaning of coal and its products, and factors affecting the environmental balance of energy usage and solutions for the future, were discussed in the Institute and these are presented under six groups in the book: Part 1. Structure and reactivity of coal; Part 2. Factors affecting environmental balance; Part 3. Pre-usage cleaning operations and processes; Part 4. Upgrading of coal liquids and gases; Part 5. Oxygen enriched processes; and Part 6. Probable future solution for energy and pollution problems. Separate abstracts have been prepared for all the lectures

Cleaning and sterilization in biotechnological clean system. Biotechnological clean system no senjo sakkin

Energy Technology Data Exchange (ETDEWEB)

Inoue, M.

1994-02-20

Despite their usefulness for mankind, many of microorganisms are generally emphasized of the aspect of their harmfulness as decomposable and pathogenic microorganisms, apt to implant people with wrong preconception. Moreover, the food industries have a habitual practice that they leave unexpectedly unclean conditions unattended. This paper indicates such actual circumstances by quoting various examples, and introduces characteristics and test results on commercially available chemicals having excellent cleansing and sterilizing effects. High-pressure and high-temperature sterilization processes fit the purpose of preservation, but secondary contamination may occur in subsequent processing, for example, from the ceiling and walls of a work room, or operators' fingers. Problems exist there that should be considered in biotechnological clean systems. Technologies have been advanced that mix a small amount of chemicals into plastic sheets, wall materials, and floor materials so that their surfaces are kept away from growth of microorganisms for extended periods of time. About 300 kinds of chemicals have been developed, and are available commercially. 3 refs., 8 figs.

Rudimentary Cleaning Compared to Level 300A

Science.gov (United States)

Arpin, Christina Y. Pina; Stoltzfus, Joel

2012-01-01

A study was done to characterize the cleanliness level achievable when using a rudimentary cleaning process, and results were compared to JPR 5322.1G Level 300A. While it is not ideal to clean in a shop environment, some situations (e.g., field combat operations) require oxygen system hardware to be maintained and cleaned to prevent a fire hazard, even though it cannot be sent back to a precision cleaning facility. This study measured the effectiveness of basic shop cleaning. Initially, three items representing parts of an oxygen system were contaminated: a metal plate, valve body, and metal oxygen bottle. The contaminants chosen were those most likely to be introduced to the system during normal use: oil, lubricant, metal shavings/powder, sand, fingerprints, tape, lip balm, and hand lotion. The cleaning process used hot water, soap, various brushes, gaseous nitrogen, water nozzle, plastic trays, scouring pads, and a controlled shop environment. Test subjects were classified into three groups: technical professionals having an appreciation for oxygen hazards; professional precision cleaners; and a group with no previous professional knowledge of oxygen or precision cleaning. Three test subjects were in each group, and each was provided with standard cleaning equipment, a cleaning procedure, and one of each of the three test items to clean. The results indicated that the achievable cleanliness level was independent of the technical knowledge or proficiency of the personnel cleaning the items. Results also showed that achieving a Level 300 particle count was more difficult than achieving a Level A nonvolatile residue amount.

Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide.

Science.gov (United States)

Timm, Rainer; Head, Ashley R; Yngman, Sofie; Knutsson, Johan V; Hjort, Martin; McKibbin, Sarah R; Troian, Andrea; Persson, Olof; Urpelainen, Samuli; Knudsen, Jan; Schnadt, Joachim; Mikkelsen, Anders

2018-04-12

Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor-oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor-oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

EM-21 Alternative Enhanced Chemical Cleaning Program For Sludge Heel Removal

International Nuclear Information System (INIS)

Hay, M.; King, W.; Martino, C.

2009-01-01

Preliminary studies in the EM-21 Alternative Chemical Cleaning Program have focused on understanding the dissolution of Hematite (a primary sludge heel phase) in oxalic acid, with a focus on minimizing oxalic acid usage. Literature reviews, thermodynamic modeling, and experimental results have all confirmed that pH control, preferably using a supplemental proton source, is critical to oxalate minimization. With pH control, iron concentrations as high as 0.103 M have been obtained in 0.11 M oxalic acid. This is consistent with the formation of a 1:1 (iron:oxalate) complex. The solubility of Hematite in oxalic acid has been confirmed to increase by a factor of 3 when the final solution pH decreases from 5 to below 1. This is consistent with literature predictions of a shift in speciation from a 1:3 to 1:1 as the pH is lowered. Above a solution pH of 6, little Hematite dissolves. These results emphasize the importance of pH control in optimizing Hematite dissolution in oxalic acid.

On-line chemical cleaning of pipelines; Limpieza quimica de ductos en linea

Energy Technology Data Exchange (ETDEWEB)

Cross, Michael Brent [Brenntag Stinnes Logistics, Muelheim/Ruhr (Germany)

2003-07-01

The concern of efficiency and maintenance in the pipeline industry, due to fluids and sediments, has led the development of new methods of cleaning. Some methods of cleaning are described in this work with their advantages and disadvantages.

Science for Energy Technology: Strengthening the Link Between Basic Research and Industry

Energy Technology Data Exchange (ETDEWEB)

None

2010-04-01

The nation faces two severe challenges that will determine our prosperity for decades to come: assuring clean, secure, and sustainable energy to power our world, and establishing a new foundation for enduring economic and jobs growth. These challenges are linked: the global demand for clean sustainable energy is an unprecedented economic opportunity for creating jobs and exporting energy technology to the developing and developed world. But achieving the tremendous potential of clean energy technology is not easy. In contrast to traditional fossil fuel-based technologies, clean energy technologies are in their infancy, operating far below their potential, with many scientific and technological challenges to overcome. Industry is ultimately the agent for commercializing clean energy technology and for reestablishing the foundation for our economic and jobs growth. For industry to succeed in these challenges, it must overcome many roadblocks and continuously innovate new generations of renewable, sustainable, and low-carbon energy technologies such as solar energy, carbon sequestration, nuclear energy, electricity delivery and efficiency, solid state lighting, batteries and biofuels. The roadblocks to higher performing clean energy technology are not just challenges of engineering design but are also limited by scientific understanding.Innovation relies on contributions from basic research to bridge major gaps in our understanding of the phenomena that limit efficiency, performance, or lifetime of the materials or chemistries of these sustainable energy technologies. Thus, efforts aimed at understanding the scientific issues behind performance limitations can have a real and immediate impact on cost, reliability, and performance of technology, and ultimately a transformative impact on our economy. With its broad research base and unique scientific user facilities, the DOE Office of Basic Energy Sciences (BES) is ideally positioned to address these needs. BES has laid

Cleaning Challenges of High-κ/Metal Gate Structures

KAUST Repository

Hussain, Muhammad Mustafa; Shamiryan, Denis G.; Paraschiv, Vasile; Sano, Kenichi; Reinhardt, Karen A.

2010-01-01

High-κ/metal gates are used as transistors for advanced logic applications to improve speed and eliminate electrical issues associated with polySi and SiO2 gates. Various integration schemes are possible and will be discussed, such as dual gate, gate-first, and gate-last, both of which require specialized cleaning and etching steps. Specific areas of discussion will include cleaning and conditioning of the silicon surface, forming a high-quality chemical oxide, removal of the high-κ dielectric with selectivity to the SiO2 layer, cleaning and residue removal after etching, and prevention of galvanic corrosion during cleaning. © 2011 Scrivener Publishing LLC. All rights reserved.

Cleaning Challenges of High-κ/Metal Gate Structures

KAUST Repository

Hussain, Muhammad Mustafa

2010-12-20

High-κ/metal gates are used as transistors for advanced logic applications to improve speed and eliminate electrical issues associated with polySi and SiO2 gates. Various integration schemes are possible and will be discussed, such as dual gate, gate-first, and gate-last, both of which require specialized cleaning and etching steps. Specific areas of discussion will include cleaning and conditioning of the silicon surface, forming a high-quality chemical oxide, removal of the high-κ dielectric with selectivity to the SiO2 layer, cleaning and residue removal after etching, and prevention of galvanic corrosion during cleaning. © 2011 Scrivener Publishing LLC. All rights reserved.

Ethanol Basics (Fact Sheet)

Energy Technology Data Exchange (ETDEWEB)

2015-01-01

Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

Experimental investigation on cleaning of corroded ancient coins using a Nd:YAG laser

Science.gov (United States)

Zhu, Huazhong; Lu, Jian; Ni, Xiaowu; Shen, Zhonghua

2017-05-01

The objective of the work reported is to study experimentally on the removal of corrosion layer from the ancient coins using laser beam as the conservation tool. With the use of Q-switched Nd:YAG laser radiation at 1064 nm, dry laser cleaning, steam laser cleaning and chemical-assisted laser cleaning were used to find out a more suitable and efficient laser treatment for corrosion removal. Cleaning tests were performed on ancient Chinese coins. Experimental results shows that the dry laser cleaning was not successful at removing all types of corrosion crust. It was possible to remove the outer thicker layer of the corrosion products (typically known as patina), but failed on the thinner layer of cuprite. The steam laser cleaning could decrease the initial removal threshold and improve the removal efficiency especially for the oxidation with powdery structure. As for chemical-assisted laser treatment, the cleaning results demonstrate that the combination of laser and chemical reagent could provide a considerable improvement in corrosion removal compared with the conventional laser treatments. Most of the corrosion contaminant was stripped, even the cuprite layer. Moreover, no secondary pollution was formed on the cleaned surface. X-ray fluorescence was applied to determine the variation of composition of surface layer and bulk metal before and after the coins cleaned. It shows that all of the three laser treatments were efficient to reduce the chlorine concentration on the surface of the coins more than 75%.

Engineered Transport in Microporous Materials and Membranes for Clean Energy Technologies.

Science.gov (United States)

Li, Changyi; Meckler, Stephen M; Smith, Zachary P; Bachman, Jonathan E; Maserati, Lorenzo; Long, Jeffrey R; Helms, Brett A

2018-02-01

Many forward-looking clean-energy technologies hinge on the development of scalable and efficient membrane-based separations. Ongoing investment in the basic research of microporous materials is beginning to pay dividends in membrane technology maturation. Specifically, improvements in membrane selectivity, permeability, and durability are being leveraged for more efficient carbon capture, desalination, and energy storage, and the market adoption of membranes in those areas appears to be on the horizon. Herein, an overview of the microporous materials chemistry driving advanced membrane development, the clean-energy separations employing them, and the theoretical underpinnings tying membrane performance to membrane structure across multiple length scales is provided. The interplay of pore architecture and chemistry for a given set of analytes emerges as a critical design consideration dictating mass transport outcomes. Opportunities and outstanding challenges in the field are also discussed, including high-flux 2D molecular-sieving membranes, phase-change adsorbents as performance-enhancing components in composite membranes, and the need for quantitative metrologies for understanding mass transport in heterophasic materials and in micropores with unusual chemical interactions with analytes of interest. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PROBIOTIC CLEANING PREPARATIONS VERSUS CHEMICAL DISINFECTANTS

Directory of Open Access Journals (Sweden)

W. Luepcke

2017-12-01

Full Text Available Probiotic detergents are increasingly used and are a real alternative for limiting the use of chemical cleaners, chemical disinfectants and antibiotics. They therefore have a great future because they contribute to animal health, to the hygienic production of food products of animal origin and to their harmlessness and to consumer health and environmental protection where they even have a beneficial effect on the microflora apart from chemical disinfectants that have a negative impact and destroy the beneficial microflora.

Fouling and cleaning of seawater reverse osmosis membranes in Kalpakkam Nuclear Desalination Plant

International Nuclear Information System (INIS)

Murugan, V.; Rajanbabu, K.; Tiwari, S.A.; Balasubramanian, C.; Yadav, Manoj Kumar; Dangore, A.Y.; Prabhakar, S.; Tewari, P.K.

2005-01-01

Seawater reverse osmosis plant of 1800 m 3 /day capacity is a part of 6300 m 3 /day capacity Nuclear Desalination Demonstration Project, at Kalpakkam. The plant was commissioned in October 2002 and is in continuous operation. This paper deals with types of foulants, membrane cleaning procedures and the improvement in the reverse osmosis system after cleaning. This paper also describes analysis of foulants which may consist of adsorbed organic compounds, particulate matter, microorganisms, metallic oxides and chemical cleaning procedure to be adopted, which is characteristics of sea water used as the membrane foulant is very much specific with respect to the sea water constituents. The cleaning of the membranes in Kalpakkam Nuclear Desalination plant were taken up as the quality of permeate deteriorated and differential pressure across membrane had gone-up. This paper essentially deals with selection of cleaning chemicals, the experience gained in cleaning procedure adopted and effects of cleaning for the membrane system. (author)

Chemical cleaning and decontamination of equipments in Rajasthan Atomic Power Station-2, Kota, NPCIL

International Nuclear Information System (INIS)

Pal, P.K.; Saini, S.L.

2008-01-01

Heat exchanger of End Shield Cooling System of RAPS-2 made up of 70:30 cupronickel was cleaned with a cleaning solution containing 5% sulphamic acid for periods of around 10 hours at a temperature of 60 deg C. The cleaning was attempted to remove the deposit inside the tube of heat exchanger to make a path of the probe to go inside the tube for eddy current testing for measurement of wall thinning. During the campaign 20 kg of CaCO 3 and 5 kg of SiO 2 were removed. Pre-cooler of heat transport system of RAPS-2 made up of monel was cleaned with a cleaning solution containing 5% citric acid, 1% ascorbic acid and 1% NTA at 50-60 deg C temperature for about 20 hours. The cleaning was attempted to remove the deposit inside the tube of pre cooler to make a path of the probe to go inside the tube for eddy current testing for measurement of wall thinning. For the pre-cooler a decontamination factor of 2 to 3 was obtained. The paper describes about the analysis of the deposit, the cleaning process, and schematic diagram of the process. (author)

Carbon dioxide nucleation as a novel cleaning method for ultrafiltration membranes

KAUST Repository

Al Ghamdi, Mohanned

2016-12-08

The use of low-pressure membranes, mainly ultrafiltration (UF), has emerged in the last decade and began to show acceptance as a novel pretreatment process for seawater reverse osmosis (SWRO) desalination. This is mainly due to the superior water quality provided by these membranes, in addition to reduction in chemicals consumption compared to conventional methods. However, membrane fouling remains the main drawback of this technology. Therefore, frequent cleaning of these membranes is required to maintain water flux and its quality. Usually, after a series of backwash using UF permeate chemical cleaning is required under some conditions to fully recover the operating flux. Frequent chemical cleaning will probably decrease the life time of the membrane, increase costs, and will have some effects on the environment. The new cleaning method proposed in this study consists of using a solution saturated with carbon dioxide (CO2) to clean UF membranes. Under the drop in pressure, this solution will become in a supersaturated state and bubbles will start to nucleate on the surface of the membrane and its pores from this solution resulting in the removal of the fouling material deposited on the membrane. Different compositions of fouling solutions including the use of organic compounds such as sodium alginate and colloidal 5 silica with different concentrations were studied using synthetic seawater with different concentrations. This cleaning method was then compared to the backwash using Milli-Q water and showed an improved performance compared to it. An operational modification to this cleaning technique was then investigated which includs a series of sudden pressure drop during the backwash process. This enhanced technique showed an even better performance in cleaning the membrane, especially at severe fouling conditions. In most cases, the membrane permeability was fully recovered even at harsh conditions where conventional backwash failed to maintain a stable

Experimental study on air cleaning effect of clean air heat pump and its impact on ventilation requirement

DEFF Research Database (Denmark)

Fang, Lei; Sheng, Ying; Nie, Jinzhe

2017-01-01

This study investigated air purification effect of a Clean-Air Heat Pump (CAHP) which combined a desiccant wheel with a heat pump for both air cleaning and HVAC of buildings. The experiment was conducted in a field lab at four different outdoor air supply rates with and without air cleaning by CAHP....... Both sensory assessments of perceived air quality and chemical measurements of TVOC concentrations were conducted for evaluating the air cleaning performance of the CAHP. The results of experiment showed that running the CAHP improved significantly perceived air quality. At 2 L/s per person of outdoor...... air supply rate with operating the CAHP, the air quality was equivalent to the value at the higher outdoor air supply rate of 10 L/s per person without running CAHP. The TVOC measurements observed over 92% of efficiency on removal of indoor air VOCs and no VOCs accumulation on the desiccant wheel...

Impact of operation conditions, foulant adsorption, and chemical cleaning on the nanomechanical properties of ultrafiltraion hollow fiber membranes

KAUST Repository

Gutierrez, Leonardo

2018-04-06

This study analyzed the change in nanomechanical properties of ultrafiltration hollow fiber membranes harvested from pilot-scale units after twelve months of operation. Quantitative Nanomechanical Mapping technique was used to distinguish between adhesion, dissipation, deformation, and modulus while simultaneously generating a topographic image of membranes. Nanomechanical maps of virgin membranes evidenced surfaces of heterogeneous properties and were described by probability density functions. Operating conditions and feed quality exerted an impact on membranes. Clean harvested membranes showed a higher mean modulus and dissipation, and a lower deformation than virgin membranes, indicating stiffer membranes of lower elastic deformation. A significant fraction of these measurements displayed peak values deviating from the distribution; which represents regions of the membrane with properties highly differing from the probability density function. The membrane polymeric material experienced severe physicochemical changes by foulant adsorption and reaction with cleaning agents. Foulant adsorption on membranes was heterogeneous in both morphology and mechanical properties and could not be statistically described. Foulants, i.e., mainly consisting of polysaccharides and proteinaceous structures, displayed low elastic deformation and high roughness and adhesion. The presence of foulants after chemical cleaning and their high adhesion would be a direct nanoscale evidence of irreversible fouling. By the end of the operation, the Trans-Membrane Pressure experienced a 40% increase. The cleaning process was not able to fully recover the initial TMP, indicating irreversible fouling, i.e., permanent change in membrane characteristics and decrease in performance. These results suggest a link between the macroscopic properties and nanomechanical characteristics of membranes. This study advances our nanoscale understanding of the impact of fouling and operating conditions on

Characterization of Carbon-Contaminated B4C-Coated Optics after Chemically Selective Cleaning with Low-Pressure RF Plasma.

Science.gov (United States)

Moreno Fernández, H; Rogler, D; Sauthier, G; Thomasset, M; Dietsch, R; Carlino, V; Pellegrin, E

2018-01-22

Boron carbide (B 4 C) is one of the few materials that is expected to be most resilient with respect to the extremely high brilliance of the photon beam generated by free electron lasers (FELs) and is thus of considerable interest for optical applications in this field. However, as in the case of many other optics operated at light source facilities, B 4 C-coated optics are subject to ubiquitous carbon contaminations. Carbon contaminations represent a serious issue for the operation of FEL beamlines due to severe reduction of photon flux, beam coherence, creation of destructive interference, and scattering losses. A variety of B 4 C cleaning technologies were developed at different laboratories with varying success. We present a study regarding the low-pressure RF plasma cleaning of carbon contaminated B 4 C test samples via inductively coupled O 2 /Ar, H 2 /Ar, and pure O 2 RF plasma produced following previous studies using the same ibss GV10x downstream plasma source. Results regarding the chemistry, morphology as well as other aspects of the B 4 C optical coating before and after the plasma cleaning are reported. We conclude that among the above plasma processes only plasma based on pure O 2 feedstock gas exhibits the required chemical selectivity for maintaining the integrity of the B 4 C optical coatings.

Temperature control of thermal-gas-dynamical installation in cleaning oil-well tubes

Science.gov (United States)

Penner, V. A.; Martemyanov, D. B.; Pshenichnikova, V. V.

2017-08-01

The article provides the study results of cleaning oil-well tubes, the oil-well tube failure reasons for service by their types have been considered. The chemical method of cleaning oil-well tubes as the least expensive has been reviewed when acid solution moves to the interptube space mixing up with oil and liquidates paraffin and pitches deposits on the internal pipe surface. Except the chemical method of pipes cleaning the mechanical one was considered as well. Also the disadvantages -such as the low productivity of cleaning and design complexity- of this deposits removal method on the internal oil-well tube surface have been considered. An effective method for cleaning oil-well tubing from paraffin and pitches by the thermodynamic plant based on the aircraft engine has been introduced for the first time. The temperature distribution graph in the gas stream at the engine output has been given.

Steam generators secondary side chemical cleaning at Point Lepreau using the Siemens high temperature process

International Nuclear Information System (INIS)

Verma, K.; MacNeil, C.; Odar, S.; Kuhnke, K.

1997-01-01

This paper describes the chemical cleaning of the four steam generators at the Point Lepreau facility, which was accomplished as a part of a normal service outage. The steam generators had been in service for twelve years. Sludge samples showed the main elements were Fe, P and Na, with minor amounts of Ca, Mg, Mn, Cr, Zn, Cl, Cu, Ni, Ti, Si, and Pb, 90% in the form of Magnetite, substantial phosphate, and trace amounts of silicates. The steam generators were experiencing partial blockage of broached holes in the TSPs, and corrosion on tube ODs in the form of pitting and wastage. In addition heat transfer was clearly deteriorating. More than 1000 kg of magnetite and 124 kg of salts were removed from the four steam generators

Atomic hydrogen cleaning of GaAs photocathodes

International Nuclear Information System (INIS)

Poelker, M.; Price, J.; Sinclair, C.

1997-01-01

It is well known that surface contaminants on semiconductors can be removed when samples are exposed to atomic hydrogen. Atomic H reacts with oxides and carbides on the surface, forming compounds that are liberated and subsequently pumped away. Experiments at Jefferson lab with bulk GaAs in a low-voltage ultra-high vacuum H cleaning chamber have resulted in the production of photocathodes with high photoelectron yield (i.e., quantum efficiency) and long lifetime. A small, portable H cleaning apparatus also has been constructed to successfully clean GaAs samples that are later removed from the vacuum apparatus, transported through air and installed in a high-voltage laser-driven spin-polarized electron source. These results indicate that this method is a versatile and robust alternative to conventional wet chemical etching procedures usually employed to clean bulk GaAs

Ultrasonic cleaning of electrodes of wire chambers

International Nuclear Information System (INIS)

Krasnov, V.A.; Kurepin, A.B.; Razin, V.I.

1980-01-01

A technological process of cleaning electrodes and working volume surfaces of wire chambers from contaminations by the simultaneous mechanical action of the energy of ultrasonic oscillations and the chemical action of detergents is discussed. A device for cleaning wire electrodes of proportional chambers of 0.3x0.4 m is described. The device uses two ultrasonic generators with a total power of 0.5 kW. As a detergent use is made of a mixture of ethyl alcohol, gasoline and freon. In the process of cleaning production defects can be detected in the wire chambers which makes it possible to timely remove the defects. Measurements of the surface resistance of fiberglass laminate of printed drift chamber electrodes at a voltage of 2 kV showed that after completing the cleaning process the resistance increases 15-20%

Are safety data sheets for cleaning products used in Norway a factor contributing to the risk of workers exposure to chemicals?

Directory of Open Access Journals (Sweden)

Abdulqadir M. Suleiman

2014-10-01

Full Text Available Objectives: Cleaning products are considered less hazardous than those used in other sectors. Suppliers and distributors are less conscientious when it comes to informing users on health risks. The aim of the study was to elaborate on the usefulness and clarity of information in the safety data sheets (SDS for cleaning products, and considering if the use of these SDSs can be seen as a risk factor towards occupational exposure to hazardous chemicals in the sector. Material and Methods: Safety data sheets were selected based on the risk level of the product assigned in an industrial sector scheme. 320 SDSs for cleaning products were reviewed. Constituent components found in the products over a given threshold were listed and available information thereof used to assess the perceived non-hazard consideration of the chemicals. Results: The contents of the SDSs was generic and mostly incomplete. Safety measures and health information lacked sufficient specificity despite varying compositions and concentrations of components. There is generally incompatibility between mentioned sections on the suggested non-hazardous nature of the products and health effects. Not all substances used in these products have harmonized classifications, which makes them open to various classification of the products and the suggested safety measures. This results in different companies classifying similar products differently. Risk management measures and suggested personal protective equipment (PPEs are given haphazardly. Physical properties relevant to risk assessment are not included. Conclusions: The safety data sheets are ambiguous, and they lack relevant and important information. Inadequate information and risk assessment concerning the products can lead to workers being exposed to hazardous chemicals. Underestimation of the hazard contribution of the components of the products and the insufficient, non-objective mention of appropriate control and protective

Clean Slate 2 Revegetation and Monitoring Plan

International Nuclear Information System (INIS)

David Anderson

1998-01-01

This document is a reclamation plan for short-term and long-term stabilization of land disturbed by activities associated with interim clean-up of radionuclide-contaminated surface soil at Clean Slate 2 located northwest of the Nevada Test Site on the Nellis Air Force Range. Surface soils at Clean Slate 2 were contaminated as a result of the detonation of a device containing plutonium and depleted uranium using chemical explosives. Excavation of contaminated soils at Clean Slate 2 will follow procedures similar to those used during the cleanup of the Double Tracks and Clean Slate 1 sites. A maximum of approximately 33 cm (12 in) of the surface soils will be excavated and removed from the site. Near ground zero, where contamination levels are highest, approximately 2 m (7 ft) of soil may be removed. The maximum area to be excavated is estimated to be 18.4 hectares (45.4) acres. In addition to the disturbance associated with soil excavation, approximately 2.0 hectares (5.0) acres will be disturbed by the construction of staging areas and placement of support facilities. Short term stabilization consists of an application of a chemical soil stabilizer and long-term stabilizations involves the establishment of a permanent vegetative cover using selective native plant species, site preparation techniques, increasing organic matter and water holding capacity, irrigation to ensure seed germination and plant establishment. The cleanup site will be monitored to ensure success of revegetation and resuspension of soil particles is within established limits

Processing method for chemical cleaning liquid on the secondary side of steam generator

International Nuclear Information System (INIS)

Nishihara, Yukio; Inagaki, Yuzo.

1993-01-01

Upon processing nitrilotriacetate (NTA), Fe liquid wastes mainly comprising Fe and Cu liquid wastes mainly comprising ethylene diamine and Cu generated upon chemical cleaning on the secondary side of a steam generator, pH of the Fe liquid wastes is lowered to deposit and separate NTA. Then, Fe ions in a filtrates are deposited on a cathode by electrolysis, as well as remaining NTA is decomposed by oxidation at an anode by O 2 gas. Cu liquid wastes are reacted with naphthalene disulfate and Ba ions and the reaction products are separated by deposition as sludges. Remaining Cu ions in the filtrates are deposited on the cathode by electrolysis. With such procedures, concentration of COD(NTA), Fe ions and Cu ions can greatly be reduced. Further, since capacity of the device can easily be increased in this method, a great amount of liquid wastes can be processed in a relatively short period of time. (T.M.)

Characterization of Cleaning and Disinfecting Tasks and Product Use Among Hospital Occupations

Science.gov (United States)

Saito, Rena; Virji, M. Abbas; Henneberger, Paul K.; Humann, Michael J.; LeBouf, Ryan F.; Stanton, Marcia L.; Liang, Xiaoming; Stefaniak, Aleksandr B.

2016-01-01

Background Healthcare workers have an elevated prevalence of asthma and related symptoms associated with the use of cleaning/disinfecting products. The objective of this study was to identify and characterize cleaning/disinfecting tasks and products used among hospital occupations. Methods Workers from 14 occupations at five hospitals were monitored for 216 shifts, and work tasks and products used were recorded at five-minute intervals. The major chemical constituents of each product were identified from safety data sheets. Results Cleaning and disinfecting tasks were performed with a high frequency at least once per shift in many occupations. Medical equipment preparers, housekeepers, floor strippers/waxers, and endoscopy technicians spent on average 108–177 min/shift performing cleaning/disinfecting tasks. Many occupations used products containing amines and quaternary ammonium compounds for > 100 min/shift. Conclusions This analysis demonstrates that many occupations besides housekeeping incur exposures to cleaning/disinfecting products, albeit for different durations and using products containing different chemicals. PMID:25351791

Hierarchical surfaces for enhanced self-cleaning applications

Science.gov (United States)

Fernández, Ariadna; Francone, Achille; Thamdrup, Lasse H.; Johansson, Alicia; Bilenberg, Brian; Nielsen, Theodor; Guttmann, Markus; Sotomayor Torres, Clivia M.; Kehagias, Nikolaos

2017-04-01

In this study we present a flexible and adaptable fabrication method to create complex hierarchical structures over inherently hydrophobic resist materials. We have tested these surfaces for their superhydrophobic behaviour and successfully verified their self-cleaning properties. The followed approach allow us to design and produce superhydrophobic surfaces in a reproducible manner. We have analysed different combination of hierarchical micro-nanostructures for their application to self-cleaning surfaces. A static contact angle value of 170° with a hysteresis of 4° was achieved without the need of any additional chemical treatment on the fabricated hierarchical structures. Dynamic effects were analysed on these surfaces, obtaining a remarkable self-cleaning effect as well as a good robustness over impacting droplets.

Cleaning of Sodium in the Cold Trap

International Nuclear Information System (INIS)

Kim, Byung Ho; Jeong, Ji Young; Kim, Jong Man; Choi, Byung Hae; Nam, Ho Yun

2005-01-01

The purpose of a cleaning process is to remove the residual sodium adhering to the component walls once it has been properly drained. It is necessary to clean and decontaminate a component, especially the large components of the primary coolant system; such as the intermediate heat exchangers and the primary pump. Improper and inadequate cleaning has in a number of cases resulted in problems in the storage, handling, and reuse of components. Several types of failures due to improper cleaning procedures have been defined in the past. Inadequate and incomplete removal of sodium results in residues which may contain metallic sodium and alkaline compounds such as sodium hydroxide, sodium oxide, sodium carbonate, and various types of alcoholates. Reinsertion of components containing these compounds into a high-temperature sodium system can result in either the intergranular penetration characteristic of a high- oxygen sodium or an accelerated corrosion due to oxygen. The methods used for cleaning sodium equipment depend on the condition and types of equipment to be cleaned and whether the equipment is to be reused. Cleaning methods are needed that will avoid a deleterious local overheating, material surface degradation or deposits, chemical, physical, or mechanical damage, and external effects. This paper discusses a steam-nitrogen gas cleaning method for the routine applications that permits the reuse of the cold trap in sodium

16th DOE nuclear air cleaning conference: proceedings

International Nuclear Information System (INIS)

First, M.W.

1981-02-01

Major topics discussed during the Sixteenth DOE Nuclear Air Cleaning Conference were: waste treatment, including volume reduction and storage; system and component response to stress and accident conditions; Three Mile Island accident; iodine adsorption; treatment and storage of noble gas: treatment of offgases from chemical processing; aerosol; behavior; containment venting; laboratory and in-place filter-testing methods; and particulate filtration. Volume I of the Proceedings has 49 papers from the following sessions; HEPA filter test methods; noble gas separation; air cleaning system design; containment venting; iodine adsorption; reprocessing offgas cleaning; critical review; filtration; filter testing; and aerosols. Volume II contains 44 papers from the sessions on: nuclear waste treatment; critical review; noble gas treatment; carbon-14 and tritium; air cleaning system response to stress; nuclear standards and safety; round table; open end; and air cleaning technology at Three Mile Island. Abstracts are provided for all of these papers

16th DOE nuclear air cleaning conference: proceedings

International Nuclear Information System (INIS)

First, M.W.

1981-02-01

Major topics discussed during the Sixteenth DOE Nuclear Air Cleaning Conference were: waste treatment, including volume reduction and storage; system and component response to stress and accident conditions; Three Mile Island accident; iodine adsorption; treatment and storage of noble gas; treatment of offgases from chemical processing; aerosol behavior; containment venting; laboratory and in-place filter-testing methods; and particulate filtration. Volume I of the Proceedings has 49 papers from the following sessions: HEPA filter test methods; noble gas separation; air cleaning system design; containment venting; iodine adsorption; reprocessing offgas cleaning; critical review; filtration, filter testing, and aerosols. Volume II contains 44 papers from the sessions on: nuclear waste treatment; critical review; noble gas treatment; carbon-14 and tritium; air cleaning system response to stress; nuclear standards and safety; round table; open end; and air cleaning technology at Three Mile Island. Abstracts are provided for all of these papers

Measuring cavitation and its cleaning effect

NARCIS (Netherlands)

Verhaagen, B.; Fernandez Rivas, David

2016-01-01

The advantages and limitations of techniques for measuring the presence and amount of cavitation, and for quantifying the removal of contaminants, are provided. After reviewing chemical, physical, and biological studies, a universal cause for the cleaning effects of bubbles cannot yet be concluded.

How Clean is Safe? Improving the Effectiveness of Decontamination of Structures and People Following Chemical and Biological Incidents

Energy Technology Data Exchange (ETDEWEB)

Vogt (Sorensen), B.M.

2003-04-03

This report describes a U.S. Department of Energy, (DOE) Chemical and Biological National Security Program project that sought to establish what is known about decontamination of structures, objects, and people following an exposure to chemical or biological materials. Specifically we sought to identify the procedures and protocols used to determine when and how people or buildings are considered ''clean'' following decontamination. To fulfill this objective, the study systematically examined reported decontamination experiences to determine what procedures and protocols are currently employed for decontamination, the timeframe involved to initiate and complete the decontamination process, how the contaminants were identified, the factors determining when people were (or were not) decontaminated, the problems encountered during the decontamination process, how response efforts of agencies were coordinated, and the perceived social psychological effects on people who were decontaminated or who participated in the decontamination process. Findings and recommendations from the study are intended to aid decision-making and to improve the basis for determining appropriate decontamination protocols for recovery planners and policy makers for responding to chemical and biological events.

Critical flux and chemical cleaning-in-place during the long-term operation of a pilot-scale submerged membrane bioreactor for municipal wastewater treatment

KAUST Repository

Wei, Chunhai

2011-01-01

The critical flux and chemical cleaning-in-place (CIP) in a long-term operation of a pilot-scale submerged membrane bioreactor for municipal wastewater treatment were investigated. Steady filtration under high flux (30 L/(m2 h)) was successfully achieved due to effective membrane fouling control by sub-critical flux operation and chemical CIP with sodium hypochlorite (NaClO) in both trans-membrane pressure (TMP) controlling mode (cleaning with high concentration NaClO of 2000-3000 mg/L in terms of effective chorine was performed when TMP rose to 15 kPa) and time controlling mode (cleanings were performed weekly and monthly respectively with low concentration NaClO (500-1000 mg/L) and high concentration NaClO (3000 mg/L)). Microscopic analysis on membrane fibers before and after high concentration NaClO was also conducted. Images of scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that NaClO CIP could effectively remove gel layer, the dominant fouling under sub-critical flux operation. Porosity measurements indicated that NaClO CIP could partially remove pore blockage fouling. The analyses from fourier transform infrared spectrometry (FTIR) with attenuated total reflectance accessory (ATR) and energy dispersive spectrometer (EDS) demonstrated that protein-like macromolecular organics and inorganics were the important components of the fouling layer. The analysis of effluent quality before and after NaClO CIP showed no obvious effect on effluent quality. © 2010 Elsevier Ltd.

Electrochemical oxidation of some basic alcohols on multiwalled ...

Indian Academy of Sciences (India)

interest and research activities on the clean and renewable energy. The need of these clean and renewable power sources is pushing up the commercialization of fuel cells. The fuel cell is an important energy conversion system, which can directly change chemical energy to electric energy with- out charge–discharge ...

Cleaning must be well planned; Rengjoeringsopplegget maa planlegges

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

Both detergents and water may damage painted and varnished surfaces in the long run. It is therefore important to choose the right cleaning method once the rooms are put to use. It is essential that a cleaning method be found that does not require great quantities of chemicals. Professional cleaning implies that a program is used that describes in detail the cleaning operation in each room. Materials used in walls often do not tolerate much moisture. If such components are cleaned by means of too much water to which is added detergents, they may swell. These walls are exposed above all the first time they are cleaned because those doing the cleaning are not aware of the situation. Some of the detergents in current use contain hazardous components. It is very important to know the individual detergent's contents of volatile components as these may cause damage. Some detergents may lead to deterioration of the surface if incorrectly used. Some contain perfume or dyes that may develop allergies. Thus, detergents must be selected with due consideration of both the subject and the personnel. Declaration and user instruction is necessary.

CLEAN CHEMICAL SYNTHESIS IN WATER

Science.gov (United States)

Newer green chemistry approach to accomplish chemical synthesis in water is summarized. Recent global developments pertaining to C-C bond forming reactions using metallic reagents and direct use of the renewable materials such as carbohydrates without derivatization are described...

Evaporator Cleaning Studies

International Nuclear Information System (INIS)

Wilmarth, W.R.

1999-01-01

Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning

Solar photocatalytic cleaning of polluted water

International Nuclear Information System (INIS)

Bockelmann, D.

1994-01-01

Alternatively to biological, physical and chemical methods of waste water cleaning, photocatalysis can be employed. In this residue-free method, titanium dioxide particles are brought into contact with polluted water as photocatalysts. Under UV irradiation at wave-lengths below 400 nm, change carriers are generated in the semiconductor particles that act so intensely oxidizing as to completely degrade almost all organic pollutants in waste water. In this process, the ultra-violet part of the solar spectrum can be harnessed to generate oxidation equivalents. Thus, solar photocatalytic waste water cleaning is excellently suited for developing countries. (BWI) [de

Determination of the Basic Friction Angle of Rock Surfaces by Tilt Tests

Science.gov (United States)

Jang, Hyun-Sic; Zhang, Qing-Zhao; Kang, Seong-Seung; Jang, Bo-An

2018-04-01

Samples of Hwangdeung granite from Korea and Berea sandstone from USA, both containing sliding planes, were prepared by saw-cutting or polishing using either #100 or #600 grinding powders. Their basic friction angles were measured by direct shear testing, triaxial compression testing, and tilt testing. The direct shear tests and triaxial compression tests on the saw-cut, #100, and #600 surfaces indicated that the most reliable results were obtained from the #100 surface: basic friction angle of 29.4° for granite and 34.1° for sandstone. To examine the effect of surface conditions on the friction angle in tilt tests, the sliding angles were measured 50 times with two surface conditions (surfaces cleaned and not cleaned after each measurement). The initial sliding angles were high regardless of rock type and surface conditions and decreased exponentially as measurements continued. The characteristics of the sliding angles, differences between tilt tests, and dispersion between measurements in each test indicated that #100 surface produced the most reliable basic friction angle measurement. Without cleaning the surfaces, the average angles for granite (32 measurements) and sandstone (23 measurements) were similar to the basic friction angle. When 20-50 measurements without cleaning were averaged, the basic friction angle was within ± 2° for granite and ± 3° for sandstone. Sliding angles using five different tilting speeds were measured but the average was similar, indicating that tilting speed (between 0.2° and 1.6°/s) has little effect on the sliding angle. Sliding angles using four different sample sizes were measured with the best results obtained for samples larger than 8 × 8 cm.

Innovative technologies on fuel assemblies cleaning for sodium fast reactors: First considerations on cleaning process

International Nuclear Information System (INIS)

Simon, N.; Lorcet, H.; Beauchamp, F.; Guigues, E.; Lovera, P.; Fleche, J. L.; Lacroix, M.; Carra, O.; Dechelette, F.; Prele, G.; Rodriguez, G.

2012-01-01

Within the framework of Sodium Fast Reactor development, innovative fuel assembly cleaning operations are investigated to meet the GEN IV goals of safety and of process development. One of the challenges is to mitigate the Sodium Water Reaction currently used in these processes. The potential applications of aqueous solutions of mineral salts (including the possibility of using redox chemical reactions) to mitigate the Sodium Water Reaction are considered in a first part and a new experimental bench, dedicated to this study, is described. Anhydrous alternative options based on Na/CO 2 interaction are also presented. Then, in a second part, a functional study conducted on the cleaning pit is proposed. Based on experimental feedback, some calculations are carried out to estimate the sodium inventory on the fuel elements, and physical methods like hot inert gas sweeping to reduce this inventory are also presented. Finally, the implementation of these innovative solutions in cleaning pits is studied in regard to the expected performances. (authors)

Innovative technologies on fuel assemblies cleaning for sodium fast reactors: First considerations on cleaning process

Energy Technology Data Exchange (ETDEWEB)

Simon, N.; Lorcet, H.; Beauchamp, F.; Guigues, E. [CEA, DEN, DTN Cadarache, F-13108 Saint-Paul-lez-Durance (France); Lovera, P.; Fleche, J. L. [CEA, DEN, DPC Saclay, F-91191 Gif-sur-Yvette (France); Lacroix, M. [CEA, DEN, DTN Cadarache, F-13108 Saint-Paul-lez-Durance (France); Carra, O. [AREVA / NP, 10 Rue Juliette Recamier, 69003 Lyon (France); Dechelette, F. [CEA, DEN, DTN Cadarache, F-13108 Saint-Paul-lez-Durance (France); Prele, G. [EDF/SEPTEN, 12-14 avenue Dutrievoz, 69628 Villeurbane Cedex (France); Rodriguez, G. [CEA, DEN, DTN Cadarache, F-13108 Saint-Paul-lez-Durance (France)

2012-07-01

Within the framework of Sodium Fast Reactor development, innovative fuel assembly cleaning operations are investigated to meet the GEN IV goals of safety and of process development. One of the challenges is to mitigate the Sodium Water Reaction currently used in these processes. The potential applications of aqueous solutions of mineral salts (including the possibility of using redox chemical reactions) to mitigate the Sodium Water Reaction are considered in a first part and a new experimental bench, dedicated to this study, is described. Anhydrous alternative options based on Na/CO{sub 2} interaction are also presented. Then, in a second part, a functional study conducted on the cleaning pit is proposed. Based on experimental feedback, some calculations are carried out to estimate the sodium inventory on the fuel elements, and physical methods like hot inert gas sweeping to reduce this inventory are also presented. Finally, the implementation of these innovative solutions in cleaning pits is studied in regard to the expected performances. (authors)

Basics about online boiler cleaning according to the Schwandorf principle; Grundlagen zur Online-Kesselreinigung nach dem Schwandorfer Prinzip

Energy Technology Data Exchange (ETDEWEB)

Krueger, Joerg [VWT Ing.-Buero, Schwandorf (Germany); Krueger, Sascha [IBK-Verfahrenstechnik, Bad Berka (Germany)

2013-10-01

In the Schwandorf waste-to-energy (WtE) plant more than ten years ago a wet online boiler cleaning system was developed which has the capability to clean the radiation passes of (WtE-, biomass- and refuse derived fuel (RDF)) boilers without damaging the boiler. During the development it was recognised that the method of atomising the washing agent (water) is highly influencing the effectiveness of cleaning by securing parts of the boiler (membrane walls). (orig.)

Hierarchical surfaces for enhanced self-cleaning applications

International Nuclear Information System (INIS)

Fernández, Ariadna; Francone, Achille; Sotomayor Torres, Clivia M; Kehagias, Nikolaos; Thamdrup, Lasse H; Johansson, Alicia; Bilenberg, Brian; Nielsen, Theodor; Guttmann, Markus

2017-01-01

In this study we present a flexible and adaptable fabrication method to create complex hierarchical structures over inherently hydrophobic resist materials. We have tested these surfaces for their superhydrophobic behaviour and successfully verified their self-cleaning properties. The followed approach allow us to design and produce superhydrophobic surfaces in a reproducible manner. We have analysed different combination of hierarchical micro-nanostructures for their application to self-cleaning surfaces. A static contact angle value of 170° with a hysteresis of 4° was achieved without the need of any additional chemical treatment on the fabricated hierarchical structures. Dynamic effects were analysed on these surfaces, obtaining a remarkable self-cleaning effect as well as a good robustness over impacting droplets. (paper)

An investigation of sodium–CO{sub 2} interaction byproduct cleaning agent for SFR coupled with S-CO{sub 2} Brayton cycle

Energy Technology Data Exchange (ETDEWEB)

Jung, Hwa-Young, E-mail: jhy0523@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Division of SFR NSSS System Design, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Lee, Jeong Ik, E-mail: jeongiklee@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Wi, Myung-Hwan, E-mail: mhwi@kaeri.re.kr [Division of SFR NSSS System Design, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ahn, Hong Joo, E-mail: ahjoo@kaeri.re.kr [Division of Nuclear Chemistry Research, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

2016-02-15

Highlights: • Study on cleaning agent was conducted to remove Na–CO{sub 2} interaction byproducts. • Screening criteria to select candidate substances as cleaning agents were suggested. • The mixtures of Na{sub 2}CO{sub 3} with NaBrO{sub 3}, NaClO{sub 3}, or NaBF{sub 4} were thermally analyzed with the TG/DTA studies. • Three candidate substances decomposed before 600 °C and did not react with Na{sub 2}CO{sub 3}. - Abstract: One of the promising future nuclear energy systems, the Sodium-cooled Fast Reactor (SFR) has been actively developed internationally. Recently, to improve safety and economics of a SFR further, coupling supercritical CO{sub 2} power cycle was suggested. However, there can be a chemical reaction between sodium and CO{sub 2} at high temperature (more than 400 °C) when the pressure boundary fails in a sodium–CO{sub 2} heat exchanger. To ensure the performance of such a system, it is important to employ a cleaning agent to recover the system back to normal condition after the reaction. When sodium and CO{sub 2} react, solid and gaseous reaction products such as sodium carbonate (Na{sub 2}CO{sub 3}) and carbon monoxide (CO) appear. Since most of solid reaction products are hard and can deteriorate system performance, quick removal of solid reaction products becomes very important for economic performance of the system. Thus, the authors propose the conceptual method to remove the byproducts with a chemical reaction at high temperature. The chemical reaction will take place between the reaction byproducts and a cleaning agent while the cleaning agent is inert with sodium. Thus, various sodium-based compounds were first investigated and three candidate substances satisfying several criteria were selected; sodium bromate (NaBrO{sub 3}), sodium chlorate (NaClO{sub 3}), and sodium tetrafluoroborate (NaBF{sub 4}). The selected substances were thermally analyzed with the TG/DTA studies. Unfortunately, it was revealed that all candidate

Radionuclide Basics: Iodine

Science.gov (United States)

... Centers Radiation Protection Contact Us Share Radionuclide Basics: Iodine Iodine (chemical symbol I) is a chemical element. ... in the environment Iodine sources Iodine and health Iodine in the Environment All 37 isotopes of iodine ...

Poor access to basic services | IDRC - International Development ...

International Development Research Centre (IDRC) Digital Library (Canada)

2015-10-28

Oct 28, 2015 ... Poor access to basic services can foster competition and fuel conflict between groups. ... Make clean water, sanitation, electricity, and other services accessible ... Poverty, inequality, and violence in urban India: Towards more ...

[Comprehension of hazard pictograms of chemical products among cleaning workers].

Science.gov (United States)

Martí Fernández, Francesc; van der Haar, Rudolf; López López, Juan Carlos; Portell, Mariona; Torner Solé, Anna

2015-01-01

To assess the comprehension among cleaning workers of the hazard pictograms as defined by the Globally Harmonized System (GHS) of the United Nations, concerning the classification, labeling and packaging of substances and mixtures. A sample of 118 workers was surveyed on their perception of the GHS hazard pictograms. Comprehensibility was measured by the percentage of correct answers and the degree to which they reflected International Organization for Standardization and American National Standards Institute standards for minimum level of comprehension. The influence of different variables to predict comprehension capacity was assessed using a logistic regression model. Three groups of pictograms could be distinguished which were statistically differentiated by their comprehensibility. Pictograms reflecting "acute toxicity" and "flammable", were described correctly by 94% and 95% of the surveyed population, respectively. For pictograms reflecting "systemic toxicity", "corrosive", "warning", "environment" and "explosive" the frequency of correct answers ranged from 48% to 64%, whereas those for pictograms "oxidizing" and "compressed gas" were interpreted correctly by only 7% of respondents. Prognostic factors for poor comprehension included: not being familiar with the pictograms, not having received training on safe use of chemical products, being an immigrant and being 54 years of age or older. Only two pictograms exceeded minimum standards for comprehension. Training, a tool proven to be effective to improve the correct interpretation of danger symbols, should be encouraged, especially in those groups with greater comprehension difficulties. Copyright belongs to the Societat Catalana de Salut Laboral.

A novel surface cleaning method for chemical removal of fouling lead layer from chromium surfaces

International Nuclear Information System (INIS)

Gholivand, Kh.; Khosravi, M.; Hosseini, S.G.; Fathollahi, M.

2010-01-01

Most products especially metallic surfaces require cleaning treatment to remove surface contaminations that remain after processing or usage. Lead fouling is a general problem which arises from lead fouling on the chromium surfaces of bores and other interior parts of systems which have interaction with metallic lead in high temperatures and pressures. In this study, a novel chemical solution was introduced as a cleaner reagent for removing metallic lead pollution, as a fouling metal, from chromium surfaces. The cleaner aqueous solution contains hydrogen peroxide (H 2 O 2 ) as oxidizing agent of lead layer on the chromium surface and acetic acid (CH 3 COOH) as chelating agent of lead ions. The effect of some experimental parameters such as acetic acid concentration, hydrogen peroxide concentration and temperature of the cleaner solution during the operation on the efficiency of lead cleaning procedure was investigated. The results of scanning electron microscopy (SEM) showed that using this procedure, the lead pollution layer could be completely removed from real chromium surfaces without corrosion of the original surface. Finally, the optimum conditions for the complete and fast removing of lead pollution layer from chromium surfaces were proposed. The experimental results showed that at the optimum condition (acetic acid concentration 28% (V/V), hydrogen peroxide 8% (V/V) and temperature 35 deg. C), only 15-min time is needed for complete removal of 3 g fouling lead from a chromium surface.

Plasma cleaning of ITER first mirrors

Science.gov (United States)

Moser, L.; Marot, L.; Steiner, R.; Reichle, R.; Leipold, F.; Vorpahl, C.; Le Guern, F.; Walach, U.; Alberti, S.; Furno, I.; Yan, R.; Peng, J.; Ben Yaala, M.; Meyer, E.

2017-12-01

Nuclear fusion is an extremely attractive option for future generations to compete with the strong increase in energy consumption. Proper control of the fusion plasma is mandatory to reach the ambitious objectives set while preserving the machine’s integrity, which requests a large number of plasma diagnostic systems. Due to the large neutron flux expected in the International Thermonuclear Experimental Reactor (ITER), regular windows or fibre optics are unusable and were replaced by so-called metallic first mirrors (FMs) embedded in the neutron shielding, forming an optical labyrinth. Materials eroded from the first wall reactor through physical or chemical sputtering will migrate and will be deposited onto mirrors. Mirrors subject to net deposition will suffer from reflectivity losses due to the deposition of impurities. Cleaning systems of metallic FMs are required in more than 20 optical diagnostic systems in ITER. Plasma cleaning using radio frequency (RF) generated plasmas is currently being considered the most promising in situ cleaning technique. An update of recent results obtained with this technique will be presented. These include the demonstration of cleaning of several deposit types (beryllium, tungsten and beryllium proxy, i.e. aluminium) at 13.56 or 60 MHz as well as large scale cleaning (mirror size: 200 × 300 mm2). Tests under a strong magnetic field up to 3.5 T in laboratory and first experiments of RF plasma cleaning in EAST tokamak will also be discussed. A specific focus will be given on repetitive cleaning experiments performed on several FM material candidates.

Hot gas cleaning, a targeted project

Energy Technology Data Exchange (ETDEWEB)

Romey, I. [University of Essen, Essen (Germany)

1998-11-01

Advanced hot gas cleaning systems will play a key role in future integrated combined cycle technologies. IGCC demonstration plants in operation or under construction are at present equipped with conventional wet gas scrubbing and cleaning systems. Feasibility studies for those IGCC plants have shown that the total efficiency of the processes can be improved using hot gas cleaning systems. However, this technology has not been developed and tested at a technical scale. Six well-known European industrial companies and research centres jointly worked together since January 1996 on a Targeted Project `Hot Gas Cleaning` to investigate and develop new hot gas cleaning systems for advanced clean coal power generation processes. In addition project work on chemical analysis and modelling was carried out in universities in England and Germany. The latest main findings were presented at the workshop. The main project aims are summarised as follows: to increase efficiency of advanced power generation processes; to obtain a reduction of alkalis and environmental emissions e.g. SO{sub 2}, NO{sub x}, CO{sub 2} and dust; and to develop the design basis for future industrial plants based on long-term operation of laboratory, pilot and demo-plants. To cover a range of possible process routes for future hot gas cleaning systems the following research programme is under investigation: removal of trace elements by different commercial and self developed sorbents; gas separation by membranes; separation of gas turbine relevant pollutants by hot filter dust and; H{sub 2}S removal and gas dedusting at high temperatures. 13 figs.

Proceedings of the 21st DOE/NRC Nuclear Air Cleaning Conference

International Nuclear Information System (INIS)

First, M.W.; Harvard Univ., Boston, MA

1991-02-01

Separate abstracts have been prepared for the papers presented at the meeting on nuclear facility air cleaning technology in the following specific areas of interest: air cleaning technologies for the management and disposal of radioactive wastes; Canadian waste management program; radiological health effects models for nuclear power plant accident consequence analysis; filter testing; US standard codes on nuclear air and gas treatment; European community nuclear codes and standards; chemical processing off-gas cleaning; incineration and vitrification; adsorbents; nuclear codes and standards; mathematical modeling techniques; filter technology; safety; containment system venting; and nuclear air cleaning programs around the world. (MB)

Study on the flotation technology for deep-cleaning of coal slime

Energy Technology Data Exchange (ETDEWEB)

Fu Xiao-heng; Shan Xiao-yun; Jiang He-jin; Li Xiang-li [China University of Mining and Technology, Beijing (China). School of Chemical and Environmental Engineering

2006-07-01

The paper introduced the basic principle and special features of deep-cleaning of coal slime by flotation, first, separating the slime by conventional flotation to give a relatively low ash concentrate, a tailing containing an ash as high as possible, followed by flocculation-flotation to recover additional low ash concentrate. The regressive release flotation test and microphoto indicated that the middling consists mainly of intergrowth particles of coal and minerals. Comparison between deep-cleaning and conventional flotation results denoted that, at approximately same concentrate ash, its yield by deep-cleaning was 46.06 percent point higher, and at similar yield, its concentrate ash, 1.78 percent point lower. The performance by deep-cleaning is even better than that by regressive release flotation test. 4 refs., 2 figs., 6 tabs.

Correlating Cleaning Thoroughness with Effectiveness and Briefly Intervening to Affect Cleaning Outcomes: How Clean Is Cleaned?

Directory of Open Access Journals (Sweden)

Robert Clifford

Full Text Available The most efficient approach to monitoring and improving cleaning outcomes remains unresolved. We sought to extend the findings of a previous study by determining whether cleaning thoroughness (dye removal correlates with cleaning efficacy (absence of molecular or cultivable biomaterial and whether one brief educational intervention improves cleaning outcomes.Before-after trial.Newly built community hospital.90 minute training refresher with surface-specific performance results.Dye removal, measured by fluorescence, and biomaterial removal and acquisition, measured with culture and culture-independent PCR-based assays, were clandestinely assessed for eight consecutive months. At this midpoint, results were presented to the cleaning staff (intervention and assessments continued for another eight consecutive months.1273 surfaces were sampled before and after terminal room cleaning. In the short-term, dye removal increased from 40.3% to 50.0% (not significant. For the entire study period, dye removal also improved but not significantly. After the intervention, the number of rooms testing positive for specific pathogenic species by culturing decreased from 55.6% to 36.6% (not significant, and those testing positive by PCR fell from 80.6% to 53.7% (P = 0.016. For nonspecific biomaterial on surfaces: a removal of cultivable Gram-negatives (GN trended toward improvement (P = 0.056; b removal of any cultivable growth was unchanged but acquisition (detection of biomaterial on post-cleaned surfaces that were contaminant-free before cleaning worsened (P = 0.017; c removal of PCR-based detection of bacterial DNA improved (P = 0.046, but acquisition worsened (P = 0.003; d cleaning thoroughness and efficacy were not correlated.At this facility, a minor intervention or minimally more aggressive cleaning may reduce pathogen-specific contamination, but not without unintended consequences.

Development of Chemical and Mechanical Cleaning Procedures for Genesis Solar Wind Samples

Science.gov (United States)

Schmeling, M.; Jurewicz, A. J. G.; Gonzalez, C.; Allums, K. K.; Allton, J. H.

2018-01-01

The Genesis mission was the only mission returning pristine solar material to Earth since the Apollo program. Unfortunately, the return of the spacecraft on September 8, 2004 resulted in a crash landing shattering the solar wind collectors into smaller fragments and exposing them to desert soil and other debris. Thorough surface cleaning is required for almost all fragments to allow for subsequent analysis of solar wind material embedded within. However, each collector fragment calls for an individual cleaning approach, as contamination not only varies by collector material but also by sample itself.

Determination of a cleaning and decontamination process using solvents

International Nuclear Information System (INIS)

Boutot, P.; Schipfer, P.

1967-03-01

This work has been carried out on samples of the white cotton serge material of which most of the working overalls of the Nuclear Research Centre are made. The aims are: - to determine,from the decontamination and cleaning points of view, the efficiency of various solvents (white-spirit, trichloroethylene, perchlorethylene and tri-chloro-trifluoroethane) and the role of additives likely to improve the treatment; - to control the textile from the wear and shrinkage points of view; - to try to develop a basic cleaning and decontamination process as a function of the possibilities of each solvent considered. (authors) [fr

Mechanical and chemical cleaning of the tubes bundles of the moisture separator reheaters (GSS) of Nuclear power plants

International Nuclear Information System (INIS)

Guerra, Patrice; Ruiz, Jose T.; Ureta, Roman; Carreres, Cristina; Virginie, Le-Guerroue

2012-09-01

The cleaning operation concerns the 'GSS' system (GSS stands for moisture separator reheaters, MSR) which are classified as 'watch quality guarantee', not classified as safety facility and subjected to Pressure Equipment regulations. The follow-up of the operational GSS (steel carbon) of EDF nuclear power plants CP0 group reveals a clog rate due to a relevant magnetite deposits that could result in equipment damage, loss of availability and loss of plant productivity. The pressure drop between inlet and outlet of the heating steam is close to maximum design criterion. The service consisted in designing, developing, qualifying and carrying out a process which removes clog from the inside of GSS U-tubes bundle located in the vapor circuit and which respects the equipment integrity and ensures the process harmlessness. This cleaning has to enable the complete removal of deposits and oxides (magnetite) in order to recover a passage diameter and a surface finish equivalent to the origin, thus avoiding the replacement of the GSS and obtaining a considerable reduction of costs. To do so, LAINSA and SOLARCA designed, developed, qualified and operated on 14 GSS bundles, by carrying out the following operations: - Cartography of the GSS tubes bundles clogging state; - Pre-Mechanical cleaning to un-block the sealed tubes and release the inside tubes passing; - Isolation of the bundle and check of leaks of the system; - Chemical cleaning with the efficiency and harmlessness parameters follow-up: - Acid Phase by means of weak organic acids to eliminate all the deposits; - Passivation phase; - Final Rinsing respecting the customer criteria; - Drying; - Waste management and waste treatment. The implementation of this operation enables the elimination of the whole deposits (magnetite) and oxides located inside the GSS tube bundle and thus to recover a passage diameter inside the tubes, and a pressure drop close to a new system and therefore to enables the

Nondestructive evaluation of the QT on the SG tubes affected by chemical cleaning

Energy Technology Data Exchange (ETDEWEB)

Shin, Ki Seok Shin; Cheon, Keun Young; Kim, Wang Bae [Central Research Institute, Daejeon (Korea, Republic of); Min, Kyong Mahn [UMI, Daejeon (Korea, Republic of)

2012-10-15

The major mechanisms of flaws detected on the currently operating steam generator(SG) tubes are wear and stress corrosion cracking(SCC) defects. Wear defect has continuously occurred in the upper tube bundle imposed to the flow induced vibration at the interaction between tube and its support structure. Meanwhile, SCC has been formed by a variety of mixed mode, such as the corrosion susceptible material, residual stress and secondary side chemical environment of the SG tubes. Recently, corrosion related defects were detected in the domestic OPR 1000 model SG tubes especially in the egg crate tube support plate(TSP), as a form of axially oriented outer diameter stress corrosion cracking (ODSCC). Therefore, the need to take corrective measures against the corrosion defects is required and various studies have been conducted to clarify the main causes of the defects. In general, as a representing SG tube materials, Ni based alloy 600 tubes have been widely applied and also adversely shown weak properties on the corrosion cracking resistivity. According to the studies on the factors developing corrosion cracking, densely accumulated sludge pile on the secondary side of the SG tubes have been mainly attributed to the formation of the corrosion defects. Therefore, it is imperative to secure applicable and efficient sludge removal process. In this paper, the chemical cleaning processes to dissolve and remove the sludge, thus promote the integrity of the SG tubes were introduced and eddy current testing(ECT) results on the pre cracked SG tubes to determine the effectiveness of those processes were represented as well.

Dry Phosphorus silicate glass etching and surface conditioning and cleaning for multi-crystalline silicon solar cell processing

International Nuclear Information System (INIS)

Kagilik, Ahmed S.

2014-01-01

As an alternative to the wet chemical etching method, dry chemical etching processes for Phosphorus silicate glass [PSG} layer removal using Trifluormethane/Sulfur Hexafluoride (CHF 3 / SF 6 ) gas mixture in commercial silicon-nitride plasma enhanced chemical vapour deposition (SiN-PECVD) system is applied. The dependence of the solar cell performance on the etching temperature is investigated and optimized. It is found that the SiN-PECVD system temperature variation has a significant impact on the whole solar cell characteristics. A dry plasma cleaning treatment of the Si wafer surface after the PSG removal step is also investigated and developed. The cleaning step is used to remove the polymer film which is formed during the PSG etching using both oxygen and hydrogen gases. By applying an additional cleaning step, the polymer film deposited on the silicon wafer surface after PSG etching is eliminated. The effect of different plasma cleaning conditions on solar cell performance is investigated. After optimization of the plasma operating conditions, the performance of the solar cell is improved and the overall gain in efficiency of 0.6% absolute is yielded compared to a cell without any further cleaning step. On the other hand, the best solar cell characteristics can reach values close to that achieved by the conventional wet chemical etching processes demonstrating the effectiveness of the additional O 2 /H 2 post cleaning treatment.(author)

Annealing free, clean graphene transfer using alternative polymer scaffolds.

Science.gov (United States)

Wood, Joshua D; Doidge, Gregory P; Carrion, Enrique A; Koepke, Justin C; Kaitz, Joshua A; Datye, Isha; Behnam, Ashkan; Hewaparakrama, Jayan; Aruin, Basil; Chen, Yaofeng; Dong, Hefei; Haasch, Richard T; Lyding, Joseph W; Pop, Eric

2015-02-06

We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications.

Steam generator cleaning campaigns at Bruce A: 1993-1996

International Nuclear Information System (INIS)

Puzzuoli, F.V.; Leinonen, P.J.; Lowe, G.A.

1997-01-01

Boiler chemical cleaning (BOCC) and high-pressure water lancing operations were performed during the Bruce A 1993 Unit 3, 1994 Unit 3, 1995 Unit 1 and 1996 Unit 3 outages to remove secondary side deposits. High-pressure water lancing focused on three boiler areas: tube support plates, to remove broached hole deposits, hot leg U-bend supports to dislodge deposits contributing to boiler tube stress corrosion cracking and tube sheets with the aim of removing accumulated sludge piles and post BOCC insoluble residues. The chemical cleaning processes applied were modified versions of the one developed by the Electric Power Research Institute/Steam Generator Owners Group. During these BOCC operations, corrosion for several key boiler materials was monitored and was well below the specified allowances

Annealing free, clean graphene transfer using alternative polymer scaffolds

International Nuclear Information System (INIS)

Wood, Joshua D; Doidge, Gregory P; Carrion, Enrique A; Koepke, Justin C; Datye, Isha; Behnam, Ashkan; Hewaparakrama, Jayan; Aruin, Basil; Chen, Yaofeng; Lyding, Joseph W; Kaitz, Joshua A; Dong, Hefei; Haasch, Richard T; Pop, Eric

2015-01-01

We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications. (paper)

An international survey of cleaning and disinfection practices in the healthcare environment.

Science.gov (United States)

Kenters, Nikki; Gottlieb, Thomas; Hopman, Joost; Mehtar, Shaheen; Schweizer, Marin L; Tartari, Ermira; Huijskens, E G W; Voss, Andreas

2018-05-14

Antimicrobial resistance has become an urgent global health priority. Basic hygiene practices and cleaning and disinfection of the hospital environment are key in preventing pathogen cross-transmission. To our knowledge no studies have assessed the worldwide differences in cleaning and disinfection practices in healthcare facilities. The electronic survey described here was developed in order to evaluate differences in healthcare facility cleaning practices around the world. The International Society of Antimicrobial Chemotherapy (ISAC, formerly ISC), Infection Prevention and Control work group developed a survey with 30 multiple-choice questions. The questions were designed to assess the current cleaning practices in healthcare settings around the world. A total of 110 healthcare professionals, representing 23 countries participated in the online survey. In 96% of the facilities a written cleaning policy was present. Training of cleaning staff occurred in 70% of the facilities at the start of employment. Cleaning practices and monitoring of these practices varied. In summary, the survey enabled assessment and recognition of widely differing global practices in approaches to environmental cleaning and disinfection. Development of guideline recommendations for cleaning and disinfection could improve practices and set minimum standards worldwide. Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Cheap non-toxic non-corrosive method of glass cleaning evaluated by contact angle, AFM, and SEM-EDX measurements.

Science.gov (United States)

Dey, Tania; Naughton, Daragh

2017-05-01

Glass surface cleaning is the very first step in advanced coating deposition and it also finds use in conserving museum objects. However, most of the wet chemical methods of glass cleaning use toxic and corrosive chemicals like concentrated sulfuric acid (H 2 SO 4 ), piranha (a mixture of concentrated sulfuric acid and 30% hydrogen peroxide), and hydrogen fluoride (HF). On the other hand, most of the dry cleaning techniques like UV-ozone, plasma, and laser treatment require costly instruments. In this report, five eco-friendly wet chemical methods of glass cleaning were evaluated in terms of contact angle (measured by optical tensiometer), nano-scale surface roughness (measured by atomic force microscopy or AFM), and elemental composition (measured by energy dispersive x-ray spectroscopy or SEM-EDX). These glass cleaning methods are devoid of harsh chemicals and costly equipment, hence can be applied in situ in close proximity with plantation such as greenhouse or upon subtle objects such as museum artifacts. Out of these five methods, three methods are based on the chemical principle of chelation. It was found that the citric acid cleaning method gave the greatest change in contact angle within the hydrophilic regime (14.25° for new glass) indicating effective cleansing and the least surface roughness (0.178 nm for new glass) indicating no corrosive effect. One of the glass sample showed unique features which were traced backed to the history of the glass usage.

Hanford tank clean up: A guide to understanding the technical issues

International Nuclear Information System (INIS)

Gephart, R.E.; Lundgren, R.E.

1995-01-01

One of the most difficult technical challenges in cleaning up the US Department of Energy's (DOE) Hanford Site in southeast Washington State will be to process the radioactive and chemically complex waste found in the Site's 177 underground storage tanks. Solid, liquid, and sludge-like wastes are contained in 149 single- and 28 double-shelled steel tanks. These wastes contain about one half of the curies of radioactivity and mass of hazardous chemicals found on the Hanford Site. Therefore, Hanford cleanup means tank cleanup. Safely removing the waste from the tanks, separating radioactive elements from inert chemicals, and creating a final waste form for disposal will require the use of our nation's best available technology coupled with scientific advances, and an extraordinary commitment by all involved. The purpose of this guide is to inform the reader about critical issues facing tank cleanup. It is written as an information resource for the general reader as well as the technically trained person wanting to gain a basic understanding about the waste in Hanford's tanks -- how the waste was created, what is in the waste, how it is stored, and what are the key technical issues facing tank cleanup. Access to information is key to better understanding the issues and more knowledgeably participating in cleanup decisions. This guide provides such information without promoting a given cleanup approach or technology use

Hanford tank clean up: A guide to understanding the technical issues

Energy Technology Data Exchange (ETDEWEB)

Gephart, R.E.; Lundgren, R.E.

1995-12-31

One of the most difficult technical challenges in cleaning up the US Department of Energy`s (DOE) Hanford Site in southeast Washington State will be to process the radioactive and chemically complex waste found in the Site`s 177 underground storage tanks. Solid, liquid, and sludge-like wastes are contained in 149 single- and 28 double-shelled steel tanks. These wastes contain about one half of the curies of radioactivity and mass of hazardous chemicals found on the Hanford Site. Therefore, Hanford cleanup means tank cleanup. Safely removing the waste from the tanks, separating radioactive elements from inert chemicals, and creating a final waste form for disposal will require the use of our nation`s best available technology coupled with scientific advances, and an extraordinary commitment by all involved. The purpose of this guide is to inform the reader about critical issues facing tank cleanup. It is written as an information resource for the general reader as well as the technically trained person wanting to gain a basic understanding about the waste in Hanford`s tanks -- how the waste was created, what is in the waste, how it is stored, and what are the key technical issues facing tank cleanup. Access to information is key to better understanding the issues and more knowledgeably participating in cleanup decisions. This guide provides such information without promoting a given cleanup approach or technology use.

Basic Chemistry for the Cement Industry.

Science.gov (United States)

Turner, Mason

This combined student workbook and instructor's guide contains nine units for inplant classes on basic chemistry for employees in the cement industry. The nine units cover the following topics: chemical basics; measurement; history of cement; atoms; bonding and chemical formulas; solids, liquids, and gases; chemistry of Portland cement…

Water-chemical regime of a fast reactor ower complex

International Nuclear Information System (INIS)

Musikhin, R.N.; Piskunov, E.M.; Samarkin, A.A.; Yurchenko, D.S.

1983-01-01

Some peculiarities of water-chemical regime of a power compleX in Shevchenko are considered. The complex comprises a desalination unit, a gas-masout heating-and-power plant and the BN-350 reactor. The compleX is used for the production of electric and thermal energy and fresh water. The power complex peculiarity is the utilization of disalinated seawater in a technological cycle along with highly mineralized seawater with a total salt content of 13.5 g/l (for cooling) in heat exchanges. A regime of ammoniacal correction of feed water was used as a basic water-chemical regime in the initial period of the BN-350 steam generator operation. Deposits composed mainly of iron oxide slime were observed on steam generator surfaces during the operation under these conditions. A conclusion is made that the regime with chelating agent providing steam generator safe operation without chemical cleaning is the most expedient one

Frequent use of household cleaning products is associated with rhinitis in Chinese children.

Science.gov (United States)

Liu, Xudong; Lao, Xiang Qian; Wong, Claudie Chiu-Yi; Tan, Lixing; Zhang, Zilong; Wong, Tze Wai; Tse, Lap-Ah; Lau, Arthur P S; Yu, Ignatius T S

2016-09-01

Despite the popular use of household cleaning products worldwide, there is no published study investigating the health effects of these products on rhinitis in children. We sought to investigate the household use of cleaning products and rhinitis patterns in Chinese children. A total of 2299 children were recruited from 21 primary schools with wide geographic coverage in Hong Kong. Self-administered questionnaires were completed by parents/guardians to collect detailed information on respiratory symptoms and household use of 14 types of chemical cleaning products, as well as clean water. Students were categorized into 4 mutually exclusive rhinitis patterns (never, occasional, frequent, and persistent). The total chemical burden (TCB) score was used as the exposure indicator by calculating the total time of exposure to the 14 cleaning products. Multinomial logistic regression was used to assess the relationship between rhinitis patterns and the use of household cleaning products. Every 10-unit increment of TCB score was associated with an increase in the odds of occasional (odds ratio [OR], 1.21; 95% CI, 1.05-1.41), frequent (OR, 1.36; 95% CI, 1.13-1.60), and persistent (OR, 1.21; 95% CI, 1.01-1.56) rhinitis after adjustment for a wide range of potential confounders. Compared with the children within the lowest tertile of TCB scores, the adjusted ORs of occasional, frequent, and persistent rhinitis in children within the highest tertile were 1.29 (95% CI, 1.01-1.65), 1.97 (95% CI, 1.40-2.76), and 1.67 (95% CI, 1.10-2.54), respectively. Frequent use of chemical cleaning products at home is associated with an increase in the odds of rhinitis in Chinese primary school children. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Central blood circulation in children at chronic combined low dose radiation and chemical action

International Nuclear Information System (INIS)

Arinchin, A.N.

2000-01-01

The state of central blood circulation and its hormonal regulation were studied in 1465 children living permanently under chronic low dose radiation and chemical action. Basic group consisted of 1093 children (579 boys and 514 girls) . 372 children (115 boys and 227 girls permanently living on 'clean' areas) were investigated in control group. Average age was 10,8 years old in basic group and 10,4 years old in the control group. Such parameters as arterial pressure, level of lead in blood and urine, adrenaline, noradrenaline and dophamine content in urine, thyroxine, iodothyronine, prostaglandins and cyclic AMP content in the blood serum has been controlled. Hypotensive states were determined to prevail in children living permanently under chronic low dose radiation and chemical action. The main pathogenic mechanism of this defeat is consider to be a reduction of the sympathoadrenal system activity combined with a decreasing of the thyroid system activity and of cyclic AMP level as well as predominance of prostaglandin depressive activity

Preliminary cleaning tests on candidate materials for APS beamline and front end UHV components

International Nuclear Information System (INIS)

Nielsen, R.; Kuzay, T.M.

1992-01-01

Comparative cleaning tests have been done on four candidate materials for use in APS beamline and front-end vacuum components. These materials are 304 SS, 304L SS, OFHC copper, and Glidcop* (Cu-Al 2 O 3 )- Samples of each material were prepared and cleaned using two different methods. After cleaning, the sample surfaces were analyzed using ESCA (Electron Spectography for Chemical Analysis). Uncleaned samples were used as a reference. The cleaning methods and surface analysis results are further discussed

Chemical cleaning-associated generation of dissolved organic matter and halogenated byproducts in ceramic MBR: Ozone versus hypochlorite.

Science.gov (United States)

Sun, Huifang; Liu, Hang; Han, Jiarui; Zhang, Xiangru; Cheng, Fangqin; Liu, Yu

2018-04-24

This study characterized the dissolved organic matter (DOM) and byproducts generated after the exposure of activated sludge to ozone and NaClO in ceramic MBR. It was found that NaClO triggered more significant release of DOM than ozone. Proteins with the molecular weight greater than 20 kDa and humic acid like-substances were the principal components of DOM generated by NaClO, while ozone was found to effectively degrade larger biopolymers to low molecular weight substances. The results showed that more than 80% of DOM generated by NaClO and ozone could pass through the 0.2-μm ceramic membrane. Furthermore, total organic chlorine (TOCl) was determined to be the principal species of halogenated byproducts in both cases, while the generation of TOCl by NaClO was much more significant than that by ozone. Only a small fraction of TOCl was removed by the 0.2-μm ceramic membrane. More importantly, the toxic bioassays further revealed that the supernatant of sludge suspension and permeate in the MBR with NaClO cleaning exhibited higher developmental toxicity to the polychaete embryos than those by ozone. The results clearly showed that on-line chemical cleaning with ozone should be a more eco-friendly and safer approach for sustaining long-term membrane permeability in ceramic MBR. Copyright © 2018 Elsevier Ltd. All rights reserved.

PRP: The Proven Solution for Cleaning Up Oil Spills

Science.gov (United States)

2006-01-01

The basic technology behind PRP is thousands of microcapsules, tiny balls of beeswax with hollow centers. Water cannot penetrate the microcapsule s cell, but oil is absorbed right into the beeswax spheres as they float on the water s surface. This way, the contaminants, chemical compounds that originally come from crude oil such as fuels, motor oils, or petroleum hydrocarbons, are caught before they settle. PRP works well as a loose powder for cleaning up contaminants in lakes and other ecologically fragile areas. The powder can be spread over a contaminated body of water or soil, and it will absorb contaminants, contain them in isolation, and dispose of them safely. In water, it is important that PRP floats and keeps the oil on the surface, because, even if oil exposure is not immediately lethal, it can cause long-term harm if allowed to settle. Bottom-dwelling fish exposed to compounds released after oil spills may develop liver disease, in addition to reproductive and growth problems. This use of PRP is especially effective for environmental cleanup in sensitive areas like coral reefs and mangroves.

The Dalian National Laboratory for Clean Energy.

Science.gov (United States)

Zhang, Tao; Li, Can; Bao, Xinhe

2012-05-01

The Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences conducts fundamental and applied research towards chemistry and chemical engineering, with strong competence in the development of new technologies. The research in this special issue, containing 19 papers, features some of the DICP's best work on sustainable energy, use of environmental resources, and advanced materials within the framework of the Dalian National Laboratory for Clean Energy (DNL). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Clean slate corrective action investigation plan

International Nuclear Information System (INIS)

1996-05-01

The Clean Slate sites discussed in this report are situated in the central portion of the Tonopah Test Range (TTR), north of the Nevada Test Site (NTS) on the northwest portion of the Nellis Air Force Range (NAFR) which is approximately 390 kilometers (km) (240 miles [mi]) northwest of Las Vegas, Nevada. These sites were the locations for three of the four Operation Roller Coaster experiments. These experiments evaluated the dispersal of plutonium in the environment from the chemical explosion of a plutonium-bearing device. Although it was not a nuclear explosion, Operation Roller Coaster created some surface contamination which is now the subject of a corrective action strategy being implemented by the Nevada Environmental Restoration Project (NV ERP) for the U.S. Department of Energy (DOE). Corrective Action Investigation (CAI) activities will be conducted at three of the Operation Roller Coaster sites. These are Clean Slate 1 (CS-1), Clean Slate 2 (CS-2), and Clean Slate 3 (CS-3) sites, which are located on the TTR. The document that provides or references all of the specific information relative to the various investigative processes is called the Corrective Action Investigation Plan (CAIP). This CAIP has been prepared for the DOE Nevada Operations Office (DOE/NV) by IT Corporation (IT)

Clean slate corrective action investigation plan

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-05-01

The Clean Slate sites discussed in this report are situated in the central portion of the Tonopah Test Range (TTR), north of the Nevada Test Site (NTS) on the northwest portion of the Nellis Air Force Range (NAFR) which is approximately 390 kilometers (km) (240 miles [mi]) northwest of Las Vegas, Nevada. These sites were the locations for three of the four Operation Roller Coaster experiments. These experiments evaluated the dispersal of plutonium in the environment from the chemical explosion of a plutonium-bearing device. Although it was not a nuclear explosion, Operation Roller Coaster created some surface contamination which is now the subject of a corrective action strategy being implemented by the Nevada Environmental Restoration Project (NV ERP) for the U.S. Department of Energy (DOE). Corrective Action Investigation (CAI) activities will be conducted at three of the Operation Roller Coaster sites. These are Clean Slate 1 (CS-1), Clean Slate 2 (CS-2), and Clean Slate 3 (CS-3) sites, which are located on the TTR. The document that provides or references all of the specific information relative to the various investigative processes is called the Corrective Action Investigation Plan (CAIP). This CAIP has been prepared for the DOE Nevada Operations Office (DOE/NV) by IT Corporation (IT).

The successful of finite element to invent particle cleaning system by air jet in hard disk drive

Science.gov (United States)

Jai-Ngam, Nualpun; Tangchaichit, Kaitfa

2018-02-01

Hard Disk Drive manufacturing has faced very challenging with the increasing demand of high capacity drives for Cloud-based storage. Particle adhesion has also become increasingly important in HDD to gain more reliability of storage capacity. The ability to clean on surfaces is more complicated in removing such particles without damaging the surface. This research is aim to improve the particle cleaning in HSA by using finite element to develop the air flow model then invent the prototype of air cleaning system to remove particle from surface. Surface cleaning by air pressure can be applied as alternative for the removal of solid particulate contaminants that is adhering on a solid surface. These technical and economic challenges have driven the process development from traditional way that chemical solvent cleaning. The focus of this study is to develop alternative way from scrub, ultrasonic, mega sonic on surface cleaning principles to serve as a foundation for the development of new processes to meet current state-of-the-art process requirements and minimize the waste from chemical cleaning for environment safety.

Efficacy of low-pressure foam cleaning compared to conventional cleaning methods in the removal of bacteria from surfaces associated with convenience food.

Science.gov (United States)

Lambrechts, A A; Human, I S; Doughari, J H; Lues, J F R

2014-09-01

Food borne illnesses and food poisoning are cause for concern globally. The diseases are often caused by food contamination with pathogenic bacteria due largely to poor sanitary habits or storage conditions. Prevalence of some bacteria on cleaned and sanitised food contact surfaces from eight convenience food plants in Gauteng (South Africa) was investigated with the view to evaluate the efficacy of the cleaning methods used with such food contact surfaces. The microbial load of eight convenience food manufacturing plants was determined by sampling stainless steel food contact surfaces after they had been cleaned and sanitised at the end of a day's shift. Samples were analysed for Total Plate Count (TPC), Escherichia coli, Salmonella species, Staphylococcus aureus and Listeria species. Results showed that 59 % of the total areas sampled for TPC failed to comply with the legal requirements for surfaces, according to the Foodstuffs, Cosmetics and Disinfectants Act ( 0.05) in terms of Listeria species isolates obtained from both cleaning methods. The LPF method proved to be the superior cleaning option for lowering TPC counts. Regardless of cleaning method used, pathogens continued to flourish on various surfaces, including dry stainless steel, posing a contamination hazard for a considerable period depending on the contamination level and type of pathogen. Intensive training for proper chemical usage and strict procedural compliance among workers for efficient cleaning procedures is recommended.

Using Phytoremediation to Clean Up Contamination at Military Installations

International Nuclear Information System (INIS)

Zellmer, S.D.; Hinchman, R.R.; Negri, M.C.; Schneider, J.F.; Gatliff, E.G.

1997-07-01

During and following World War II, wastes from the production of munitions and other military materials were disposed of using the best available practices acceptable at that time. However, these disposal methods often contaminated soil and groundwater with organic compounds and metals that require cleanup under current regulations. An emerging technology for cleaning contaminated soils and shallow groundwater is phytoremediation, an environmentally friendly, low- cost, and low-tech process. Phytoremediation encompasses all plant- influenced biological, chemical, and physical processes that aid in the uptake, degradation, and metabolism of contaminants by either plants or free-living organisms in the plant's rhizosphere. A phytoremediation system can be viewed as a biological, solar-driven, pump-and-treat system with an extensive, self-extending uptake network (the root system) that enhances the soil and below-ground ecosystem for subsequent productive use. Argonne National Laboratory (ANL) has been conducting basic and applied research in phytoremediation since 1990. Initial greenhouse studies evaluated salt-tolerant wetland plants to clean UP and reduce the volume of salty 'produced water' from petroleum wells. Results of these studies were used to design a bioreactor for processing produced water that is being demonstrated at a natural gas well in Oklahoma; this system can reduce produced water volume by about 75% in less than eight days, representing substantial savings in waste disposal cost. During 1994, ANL conducted a TNT plant uptake and in situ remediation study in a ridge-and-furrow area used for the disposal of pink water at the Joliet Army Ammunition Plant

Using Phytoremediation to Clean Up Contamination at Military Installations

Energy Technology Data Exchange (ETDEWEB)

Zellmer, S.D.; Hinchman, R.R.; Negri, M.C.; Schneider, J.F. [Argonne National Lab., IL (United States); Gatliff, E.G. [Applied Natural Sciences, Inc., Fairfield, OH (United States)

1997-07-01

During and following World War II, wastes from the production of munitions and other military materials were disposed of using the best available practices acceptable at that time. However, these disposal methods often contaminated soil and groundwater with organic compounds and metals that require cleanup under current regulations. An emerging technology for cleaning contaminated soils and shallow groundwater is phytoremediation, an environmentally friendly, low- cost, and low-tech process. Phytoremediation encompasses all plant- influenced biological, chemical, and physical processes that aid in the uptake, degradation, and metabolism of contaminants by either plants or free-living organisms in the plant`s rhizosphere. A phytoremediation system can be viewed as a biological, solar-driven, pump-and-treat system with an extensive, self-extending uptake network (the root system) that enhances the soil and below-ground ecosystem for subsequent productive use. Argonne National Laboratory (ANL) has been conducting basic and applied research in phytoremediation since 1990. Initial greenhouse studies evaluated salt-tolerant wetland plants to clean UP and reduce the volume of salty `produced water` from petroleum wells. Results of these studies were used to design a bioreactor for processing produced water that is being demonstrated at a natural gas well in Oklahoma; this system can reduce produced water volume by about 75% in less than eight days, representing substantial savings in waste disposal cost. During 1994, ANL conducted a TNT plant uptake and in situ remediation study in a ridge-and-furrow area used for the disposal of pink water at the Joliet Army Ammunition Plant.

Effect of Managerial Ownership, Free Cash Flow and Size Company Policy on Debt (Empirical Study on Industrial Enterprises Basic and Chemicals Listed in Bei)

OpenAIRE

Hasan, Mudrika Alamsyah

2013-01-01

The purpose of this study was to obtain empirical evidence about the effect of managerial ownership structure, free cash flow and the size of the companys debt policy the Basic Industry and Chemicals companies listed on the Stock Exchange.The population in this research is the basic chemical sector companies listed on the Indonesia Stock Exchange during the last three years, is from the years 2009-2011, amounting to 43 companies, using purposive sampling and the sampling results obtained by 3...

Application of surface-enhanced Raman spectroscopy (SERS) for cleaning verification in pharmaceutical manufacture.

Science.gov (United States)

Corrigan, Damion K; Cauchi, Michael; Piletsky, Sergey; Mccrossen, Sean

2009-01-01

Cleaning verification is the process by which pharmaceutical manufacturing equipment is determined as sufficiently clean to allow manufacture to continue. Surface-enhanced Raman spectroscopy (SERS) is a very sensitive spectroscopic technique capable of detection at levels appropriate for cleaning verification. In this paper, commercially available Klarite SERS substrates were employed in order to obtain the necessary enhancement of signal for the identification of chemical species at concentrations of 1 to 10 ng/cm2, which are relevant to cleaning verification. The SERS approach was combined with principal component analysis in the identification of drug compounds recovered from a contaminated steel surface.

Dry cleaning of fluorocarbon residues by low-power electron cyclotron resonance hydrogen plasma

CERN Document Server

Lim, S H; Yuh, H K; Yoon Eui Joon; Lee, S I

1988-01-01

A low-power ( 50 W) electron cyclotron resonance hydrogen plasma cleaning process was demonstrated for the removal of fluorocarbon residue layers formed by reactive ion etching of silicon dioxide. The absence of residue layers was confirmed by in-situ reflection high energy electron diffraction and cross-sectional high resolution transmission electron microscopy. The ECR hydrogen plasma cleaning was applied to contact cleaning of a contact string structure, resulting in comparable contact resistance arising during by a conventional contact cleaning procedure. Ion-assisted chemical reaction involving reactive atomic hydrogen species generated in the plasma is attributed for the removal of fluorocarbon residue layers.

Cleaning Schedule Operations in Heat Exchanger Networks

Directory of Open Access Journals (Sweden)

Huda Hairul

2018-01-01

Full Text Available Heat exchanger networks have been known to be the essential parts in the chemical industries. Unfortunately, since the performance of heat exchanger can be decreasing in transferring the heat from hot stream into cold stream due to fouling, then cleaning the heat exchanger is needed to restore its initial performance periodically. A process of heating crude oil in a refinery plant was used as a case study. As many as eleven heat exchangers were used to heat crude oil before it was heated by a furnace to the temperature required to the crude unit distillation column. The purpose of this study is to determine the cleaning schedule of heat exchanger on the heat exchanger networks due to the decrease of the overall heat transfer coefficient by various percentage of the design value. A close study on the process of heat exchanger cleaning schedule in heat exchanger networks using the method of decreasing overall heat transfer coefficient as target. The result showed that the higher the fouling value the more often the heat exchanger is cleaned because the overall heat transfer coefficient decreases quickly.

Safety in the Chemical Laboratory: Tested Disposal Methods for Chemical Wastes from Academic Laboratories.

Science.gov (United States)

Armour, M. A.; And Others

1985-01-01

Describes procedures for disposing of dichromate cleaning solution, picric acid, organic azides, oxalic acid, chemical spills, and hydroperoxides in ethers and alkenes. These methods have been tested under laboratory conditions and are specific for individual chemicals rather than for groups of chemicals. (JN)

Identifying optimal cleaning cycles for heat exchangers subject to fouling and ageing

International Nuclear Information System (INIS)

Pogiatzis, Thomas; Ishiyama, Edward M.; Paterson, William R.; Vassiliadis, Vassilios S.; Wilson, D. Ian

2012-01-01

Fouling of heat exchangers causes reduced heat transfer and other penalties. Regular cleaning represents one widely used fouling mitigation strategy, where the schedule of cleaning actions can be optimised to minimise the cost of fouling. This paper investigates, for the first time, the situation where there are two cleaning methods available so that the mode of cleaning has to be selected as well as the cleaning interval. Ageing is assumed to convert the initial deposit, labelled 'gel', into a harder and more conductive form, labelled 'coke', which cannot be removed by one of the cleaning methods. The second method can remove both the gel layer and the coke layer, but costs more and requires the unit to be off-line longer for cleaning. Experimental data demonstrating the effects of ageing are presented. The industrial application is the comparison of cleaning-in-place methods with off-line mechanical cleaning. A process model is constructed for an isolated counter-current heat exchanger subject to fouling, where ageing is described by a simple two-layer model. Solutions generated by an NLP-based approach prove to be superior to a simpler heuristic. A series of case studies demonstrate that combinations of chemical and mechanical cleaning can be superior to mechanical cleaning alone for certain combinations of parameters.

CPICOR{trademark}: Clean power from integrated coal-ore reduction

Energy Technology Data Exchange (ETDEWEB)

Wintrell, R.; Miller, R.N.; Harbison, E.J.; LeFevre, M.O.; England, K.S.

1997-12-31

The US steel industry, in order to maintain its basic iron production, is thus moving to lower coke requirements and to the cokeless or direct production of iron. The US Department of Energy (DOE), in its Clean Coal Technology programs, has encouraged the move to new coal-based technology. The steel industry, in its search for alternative direct iron processes, has been limited to a single process, COREX{reg_sign}. The COREX{reg_sign} process, though offering commercial and environmental acceptance, produces a copious volume of offgas which must be effectively utilized to ensure an economical process. This volume, which normally exceeds the internal needs of a single steel company, offers a highly acceptable fuel for power generation. The utility companies seeking to offset future natural gas cost increases are interested in this clean fuel. The COREX{reg_sign} smelting process, when integrated with a combined cycle power generation facility (CCPG) and a cryogenic air separation unit (ASU), is an outstanding example of a new generation of environmentally compatible and highly energy efficient Clean Coal Technologies. This combination of highly integrated electric power and hot metal coproduction, has been designated CPICOR{trademark}, Clean Power from Integrated Coal/Ore Reduction.

Clean Slate 1 revegetation and monitoring plan

International Nuclear Information System (INIS)

Anderson, D.C.; Hall, D.B.

1997-07-01

This document constitutes a reclamation plan for the short-term and long-term stabilization of land disturbed by activities associated with the cleanup of radionuclide contaminated surface soil at the Clean Slate 1 site. This document has been prepared to provide general reclamation practices and procedures that will be followed during restoration of the cleanup site. The results of reclamation trials at Area 11, Area 19 and more recently the reclamation demonstration plots at the Double Tracks cleanup site, have been summarized and incorporated into this reclamation and monitoring plan. The plan also contains procedures for monitoring both the effectiveness and success of short-term and long-term soil stabilization. The Clean Slate 1 site is located on the Tonopah Test Range. The surface soils were contaminated as a result of the detonation of a device containing plutonium and depleted uranium using chemical explosives. Short-term stabilization consists of the application of a chemical soil stabilizer that is applied immediately following excavation of the contaminated soils to minimize Pu resuspension. Long-term stabilization is accomplished by the establishment of a permanent vegetation

Ecological effectiveness of oil spill countermeasures: how clean is clean?

International Nuclear Information System (INIS)

Baker, J.M.

1999-01-01

This paper with 94 references examines background levels of hydrocarbons and the difficulty of defining clean. Processes and timescales for natural cleaning, and factors affecting natural cleaning timescales are considered. Ecological advantages and disadvantages of clean-up methods are highlighted, and five case histories of oil spills are summarised. The relationships between ecological and socio-economic considerations, and the need for a net environmental benefit analysis which takes into account the advantages and disadvantages of clean-up responses and natural clean-up are discussed. A decision tree for evaluating the requirement for shore clean-up is illustrated. (UK)

Clean energy: Revisiting the challenges of industrial policy

International Nuclear Information System (INIS)

Morris, Adele C.; Nivola, Pietro S.; Schultze, Charles L.

2012-01-01

Large public investments in clean energy technology arguably constitute an industrial policy. One rationale points to market failures that have not been corrected by other policies, most notably greenhouse gas emissions and dependence on oil. Another inspiration for clean energy policy reflects economic arguments of the 1980s. It suggests strategic government investments would increase U.S. firms' market share of a growing industry and thus help American firms and workers. This paper examines the reasoning for clean energy policy and concludes that: •While a case can be made that subsidizing clean energy might help address market failures, the case may be narrower than some assert, and turning theory into sound practice is no simple feat. •An appropriate price on greenhouse gases is an essential precondition to ensuring efficient incentives to develop and deploy cost-effective emissions-abating technologies. However, efficient prices alone are unlikely to generate efficient levels of basic research and development by private firms. •Government investments in clean energy are unlikely to produce net increases in employment in the long run, in part because pushing home-grown technologies at taxpayers' expense offers no guarantee that the eventual products ultimately would not be manufactured somewhere else. •Spending on clean energy technologies is not well suited to fiscal stimulus. The authors recommend that: •Federal energy spending should invest in technologies with the lowest expected cost of abatement and highest probability of market penetration. •Funding decisions ought to be insulated – as much as possible – from rent-seeking by interest groups, purely political distortions, and the parochial preferences of legislators. - Highlights: ► Clean energy technology policy may be less justifiable than many assert, and doing it well is hard. ► The government should appropriately price greenhouse gas emissions and fund technology R and D. �

Cleaning, disinfection and sterilization of surface prion contamination.

Science.gov (United States)

McDonnell, G; Dehen, C; Perrin, A; Thomas, V; Igel-Egalon, A; Burke, P A; Deslys, J P; Comoy, E

2013-12-01

Prion contamination is a risk during device reprocessing, being difficult to remove and inactivate. Little is known of the combined effects of cleaning, disinfection and sterilization during a typical reprocessing cycle in clinical practice. To investigate the combination of cleaning, disinfection and/or sterilization on reducing the risk of surface prion contamination. In vivo test methods were used to study the impact of cleaning alone and cleaning combined with thermal disinfection and high- or low-temperature sterilization processes. A standardized test method, based on contamination of stainless steel wires with high titres of scrapie-infected brain homogenates, was used to determine infectivity reduction. Traditional chemical methods of surface decontamination against prions were confirmed to be effective, but extended steam sterilization was more variable. Steam sterilization alone reduced the risk of prion contamination under normal or extended exposure conditions, but did show significant variation. Thermal disinfection had no impact in these studies. Cleaning with certain defined formulations in combination with steam sterilization can be an effective prion decontamination process, in particular with alkaline formulations. Low-temperature, gaseous hydrogen peroxide sterilization was also confirmed to reduce infectivity in the presence and absence of cleaning. Prion decontamination is affected by the full reprocessing cycle used on contaminated surfaces. The correct use of defined cleaning, disinfection and sterilization methods as tested in this report in the scrapie infectivity assay can provide a standard precaution against prion contamination. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Nanomaterials for the cleaning and pH adjustment of vegetable-tanned leather

Science.gov (United States)

Baglioni, Michele; Bartoletti, Angelica; Bozec, Laurent; Chelazzi, David; Giorgi, Rodorico; Odlyha, Marianne; Pianorsi, Diletta; Poggi, Giovanna; Baglioni, Piero

2016-02-01

Leather artifacts in historical collections and archives are often contaminated by physical changes such as soiling, which alter their appearance and readability, and by chemical changes which occur on aging and give rise to excessive proportion of acids that promote hydrolysis of collagen, eventually leading to gelatinization and loss of mechanical properties. However, both cleaning and pH adjustment of vegetable-tanned leather pose a great challenge for conservators, owing to the sensitivity of these materials to the action of solvents, especially water-based formulations and alkaline chemicals. In this study, the cleaning of historical leather samples was optimized by confining an oil-in-water nanostructured fluid in a highly retentive chemical hydrogel, which allows the controlled release of the cleaning fluid on sensitive surfaces. The chemical gel exhibits optimal viscoelasticity, which facilitates its removal after the application without leaving residues on the object. Nanoparticles of calcium hydroxide and lactate, dispersed in 2-propanol, were used to adjust the pH up to the natural value of leather, preventing too high alkalinity which causes swelling of fibers and denaturation of the collagen. The treated samples were characterized using scanning electron microscopy, controlled environment dynamic mechanical analysis, and infrared spectroscopy. The analytical assessment validated the use of tools derived from colloid and materials science for the preservation of collagen-based artifacts.

The applied technologies to access clean water for remote communities

Science.gov (United States)

Rabindra, I. B.

2018-01-01

A lot of research is done to overcome the remote communities to access clean water, yet very little is utilized and implemented by the community. Various reasons can probably be made for, which is the application of research results is assessed less practical. The aims of this paper is seeking a practical approach, how to establish criteria for the design can be easier applied, at the proper locations, the simple construction, effectively producing a volume and quality of clean water designation. The methods used in this paper is a technological model assessment of treatment/filtering clean water produced a variety of previous research, to establish a model of appropriate technology for remote communities. Various research results collected from the study of literature, while the identification of opportunities and threats to its application is done using a SWOT analysis. This article discussion is looking for alternative models of clean water filtration technology from the previous research results, to be selected as appropriate technology, easily applied and bring of many benefits to the remote communities. The conclusions resulting from the discussion in this paper, expected to be used as the basic criteria of design model of clean water filtration technologies that can be accepted and applied effectively by the remote communities.

Pollution Law - Clean Air Act

International Nuclear Information System (INIS)

Schmitt Glaeser, W.; Meins, J.W.

1982-01-01

This volume deals with how the living space air is kept clean by means of the pollution law, focussing on the documentation of central problems of pollution law by means of selected articles and court decisions. The literature and jurisdiction available on this sector of which we can hardly keep track makes such a documentation look useful and necessary. It will make working easier for those who do not have direct access to large libraries. The only intention of the guide for the pollution law which preceeds the documentation is to outline basic problems. It is intended to provide basic information in this complex field of law. At the same time, it also constitutes a 'guide' for the documentation: By naming the documentation number in the margin of the respective passage reference is made to the documented publications which deal with the legal issues considered. Using this guide, the documentation can be easily tapped. (orig.) [de

Proceedings of the 21st DOE/NRC Nuclear Air Cleaning Conference; Sessions 1--8

Energy Technology Data Exchange (ETDEWEB)

First, M.W. [ed.] [Harvard Univ., Boston, MA (United States). Harvard Air Cleaning Lab.

1991-02-01

Separate abstracts have been prepared for the papers presented at the meeting on nuclear facility air cleaning technology in the following specific areas of interest: air cleaning technologies for the management and disposal of radioactive wastes; Canadian waste management program; radiological health effects models for nuclear power plant accident consequence analysis; filter testing; US standard codes on nuclear air and gas treatment; European community nuclear codes and standards; chemical processing off-gas cleaning; incineration and vitrification; adsorbents; nuclear codes and standards; mathematical modeling techniques; filter technology; safety; containment system venting; and nuclear air cleaning programs around the world. (MB)

Alternatives to Organic Solvents in Industrial Cleaning Processes

DEFF Research Database (Denmark)

Jacobsen, Thomas

1998-01-01

To control chemical hazards in work places, substitution of harmful substances with less harmful or non-toxic products is now a method used in many countries and in many companies. It has previously been demonstrated that it is desirable and possible to use non-volatile, low-toxic vegetable...... cleaning agents in offset printing companies instead of volatile, toxic organic solvents. The present study is based on a project with the aim of defining other industrial processes, where organic solvents used for cleaning or degreasing can be replaced by non-volatile, low-toxic products, which are based...... on esters from fatty acids of vegetable origin (vegetable esters - VE).The study indicates that industrial cleaning/degreasing with organic solvents may be substituted with VEs on metal surfaces and on some coated surfaces, in manufacture of paints and inks, use of paints, use of inks (printing), metal...

Enhancing Science Teaching through Performing Marbling Art Using Basic Solutions and Base Indicators

Science.gov (United States)

Çil, Emine; Çelik, Kevser; Maçin, Tuba; Demirbas, Gülay; Gökçimen, Özlem

2014-01-01

Basic solutions are an indispensable part of our daily life. Basic solutions are commonly used in industries such as the textile industry, oil refineries, the fertilizer industry, and pharmaceutical products. Most cleaning agents, such as soap, detergent, and bleach, and some of our foods, such as chocolate and eggs, include bases. Bases are the…

Cleaning power and abrasivity of European toothpastes.

Science.gov (United States)

Wülknitz, P

1997-11-01

For 41 toothpastes available to European consumers in 1995, the cleaning efficacy was evaluated in comparison with abrasivity on dentin (RDA value). For cleaning power assessment, a modified pellicle cleaning ratio (PCR) measurement method was developed. The method is characterized by a five-day tea-staining procedure on bovine front teeth slabs on a rotating wheel, standardized brushing of the slabs in a V8 cross-brushing machine, and brightness measurement by a chromametric technique. All tested products were in accordance with the new DIN/ISO standard 11,609 for toothpastes in terms of dentin abrasivity. Not a single product exceeded an RDA value of 200. The majority of toothpastes (80%) had an RDA value below 100. Only three products surpassed the reference in cleaning power. Most products (73%) had a cleaning power (PCR value) between 20 and 80. The correlation between cleaning power and dentin abrasion was low (r = 0.66), which can be explained with the different influence on dentin and stains by factors like abrasive type, particle surface and size, as well as the chemical influence of other toothpaste ingredients. Some major trends could be shown on the basis of abrasive types. The ratio PCR to RDA was rather good in most silica-based toothpastes. A lower ratio was found in some products containing calcium carbonate or aluminum trihydrate as the only abrasive. The addition of other abrasives, such as polishing alumina, showed improved cleaning power. Some active ingredients, especially sequenstrants such as sodium tripolyphosphate or AHBP, also improve the PCR/RDA ratio by stain-dissolving action without being abrasive. The data for some special anti-stain products did not differ significantly from standard products. Compared with data measured in 1988, a general trend toward reduced abrasivity without loss of cleaning efficacy could be noticed on the European toothpaste market. This may be mostly due to the increased use of high-performance abrasives such

Plasma Cleaning

Science.gov (United States)

Hintze, Paul E.

2016-01-01

NASA's Kennedy Space Center has developed two solvent-free precision cleaning techniques: plasma cleaning and supercritical carbon dioxide (SCCO2), that has equal performance, cost parity, and no environmental liability, as compared to existing solvent cleaning methods.

Using the Chemistry of Fireworks to Engage Students in Learning Basic Chemical Principles: A Lesson in Eco-Friendly Pyrotechnics

Science.gov (United States)

Steinhauser, Georg; Klapotke, Thomas M.

2010-01-01

Fascination with fireworks and pyrotechnics can be used for educational purposes. Several aspects of pyrochemistry such as redox reactions, flame colors, or the theory of combustion can be incorporated in the curriculum to illustrate some basic chemical principles, guaranteeing a lesson that will be engaging and memorable. Beyond classic…

Continuous cleaning of heat exchanger with recirculating fluidized bed

International Nuclear Information System (INIS)

St Kollbach, J.; Dahm, W.; Rautenbach, R.

1987-01-01

Fluidized bed heat exchangers for liquids have been studied in the United States, the Netherlands, and the Federal Republic of Germany. Between 1965 and 1970, fluidized bed heat exchangers were developed in the United States as brine heaters in seawater desalination. Furthermore, their potential in the utilization of geothermal energy was tested between 1975 and 1980. In the Netherlands, fluidized bed heat exchangers have been developed since 1973 for brine heating and heat recovery in multistage flash evaporators for seawater desalination and, since about 1980, for applications in the process industry. The authors became interested in fluidized bed heat exchangers first in 1978 in connection with wastewater evaporation. The authors emphasize that the results of all these groups were in basic agreement. They can be summarized as follows: 1. The fluidized bed will in many cases maintain totally clean surfaces and neither scaling nor fouling will occur. In cases where even a fluidized bed cannot completely prevent scaling or fouling, the thickness of the layer is controlled. In these cases stable operation maintaining acceptable overall heat transfer coefficients is possible without cleaning. 2. There are always excellent heat transfer coefficients as low superficial velocities of less than ν < 0.5 m/s. 3. The pressure losses are comparable with those in normal heat exchangers since fluidized bed heat exchangers are mostly operated at low superficial velocities. 4. Feed flow may be varied between 50 and 150% or more of the design feed flow. 5. Erosion is negligible. 6. Fluidized bed particles can be manufactured from all sorts of chemically and mechanically resistant materials, such as sand, glass, ceramics, and metals

Nanogold plasmonic photocatalysis for organic synthesis and clean energy conversion.

Science.gov (United States)

Wang, Changlong; Astruc, Didier

2014-01-01

This review provides the basic concepts, an overall survey and the state-of-the art of plasmon-based nanogold photocatalysis using visible light including fundamental understanding and major applications to organic reactions and clean energy-conversion systems. First, the basic concepts of localized surface plasmon resonance (LSPR) are recalled, then the major preparation methods of AuNP-based plasmonic photocatalysts are reviewed. The major part of the review is dedicated to the latest progress in the application of nanogold plasmonic photocatalysis to organic transformations and energy conversions, and the proposed mechanisms are discussed. In conclusion, new challenges and perspectives are proposed and analyzed.

Study on surface properties of gilt-bronze artifacts, after Nd:YAG laser cleaning

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyeyoun [Division of Restoration Technology, National Research Institute of Cultural Heritage, Daejeon (Korea, Republic of); Cho, Namchul, E-mail: nam1611@hanmail.net [Department of Cultural Heritage Conservation Science, Kongju National University, Gongju, 314-701 (Korea, Republic of); Lee, Jongmyoung [Laser Engineering Group, IMT Co. Ltd, Gyeonggi (Korea, Republic of)

2013-11-01

As numerous pores are formed at plating gilt-bronze artifacts, the metal underlying the gold is corroded and corrosion products are formed on layer of gold. Through this study, the surfaces of gilt-bronze are being investigated before and after the laser irradiation to remove corrosion products of copper by using Nd:YAG laser. For gilt-bronze specimens, laser and chemical cleaning were performed, and thereafter, surface analysis with SEM-EDS, AFM, and XPS were used to determine the surface characteristics. Experimental results show that chemical cleaning removes corrosion products of copper through dissolution but it was not removed uniformly and separated the metal substrate and the gold layer. Nevertheless, through laser cleaning, some of the corrosions were removed with some damaged areas due to certain conditions and brown residues remained. Brown residues were copper corrosion products mixed with soil left within the gilt layer. It was due to surface morphology of uneven and rough gilt layer. Hence, they did not react effectively to laser beams, and thus, remained as residues. The surface properties of gilt-bronze should be thoroughly investigated with various surface analyses to succeed in laser cleaning without damages or residues.

Controlling the cost of clean air - A new clean coal technology

International Nuclear Information System (INIS)

Kindig, J.K.; Godfrey, R.L.

1991-01-01

This article presents the authors' alternative to expensive coal combustion products clean-up by cleaning the coal, removing the sulfur, before combustion. Topics discussed include sulfur in coal and the coal cleaning process, the nature of a new coal cleaning technology, the impact on Clean Air Act compliance, and the economics of the new technology

Trajectories towards clean technology. Example of volatile organic compound emission reductions

Energy Technology Data Exchange (ETDEWEB)

Belis-Bergouignan, Marie-Claude; Oltra, Vanessa; Saint Jean, Maider [IFREDE-E3i, University Montesquieu-Bordeaux IV, Avenue Leon Duguit, Pessac 33608 (France)

2004-02-20

This article is based on the observation that, up until now, corporate investment has been limited in clean technologies despite the will of governmental authorities to stimulate them in order to cope with the demands of sustainable development. The paper deals with the issue of the development of clean technologies and the role of regulations as clean technology promoters. It tries to apprehend the characteristics and specificity of clean technology from both an empirical and a theoretical point of view, so as to understand which are the most favourable (or inversely, the most detrimental) conditions for their development. We use case studies concerning the reduction of volatile organic compound (VOC) emissions in the chemical and metallurgical industries. These two examples highlight the problems created by the shift from a 'with-solvent paradigm' to a 'solvent-free paradigm' and the way clean technology trajectories may spread within such paradigms. We show that the problem of clean technology development primarily resides in some factors that impede technological adoption, although a strong and mixed incentives framework prevails. Such impediments are sector-specific, leading to different clean technology trajectories among sectors and indicating areas of sectoral intervention that could become the cornerstones of complementary technology policy.

Ultrasonic and immersion cleaning: a comparison using aqueous and fluorocarbon solvents

International Nuclear Information System (INIS)

Bond, R.D.; Kearsey, A.

1984-11-01

Decontamination is a necessary process in reducing radiation levels in the working environment in the nuclear industry. Components from active areas which require decontamination for re-use or maintenance operations. In this report, a typical chemical cleaning process using liquid pumping, airagitation and physical movement for agitation is compared with ultrasonic cleaning, now an established cleaning process in many industries. The chosen traditional method is immersion in an agitated solution of warm SDG.3 solution; an established decontaminating reagent. The decontamination effect of this process is compared with the effect of cleaning in an ultrasonic bath containing the same reagent at the same concentration and temperature. Fluorocarbon reagents are of particular interest to the nuclear industry for they offer the ability to clean electrical components without damage, and can clean product contaminated material without the risk of criticality. Such reagents are based on 1,1,2-trichloro, 1,2,2-trifluoroethane and azeotropic mixtures. This reagent and one mixture with 6% methanol were tested under agitation and ultrasonic immersion at the same temperature. Parallel control experiments were conducted using demineralised water as the cleaning media in an agitated bath. SGG3 is a good reagent for general purpose cleaning (it can remove 99% of particulate contamination) using scrubbing, immersion or spraying techniques. There is little evidence to show that ultrasonic cleaning increases its effectiveness. For special purpose fluorocarbon solvents will give satisfactory results when used in an ultrasonic system. (author)

Facile Dry Surface Cleaning of Graphene by UV Treatment

Science.gov (United States)

Kim, Jin Hong; Haidari, Mohd Musaib; Choi, Jin Sik; Kim, Hakseong; Yu, Young-Jun; Park, Jonghyurk

2018-05-01

Graphene has been considered an ideal material for application in transparent lightweight wearable electronics due to its extraordinary mechanical, optical, and electrical properties originating from its ordered hexagonal carbon atomic lattice in a layer. Precise surface control is critical in maximizing its performance in electronic applications. Graphene grown by chemical vapor deposition is widely used but it produces polymeric residue following wet/chemical transfer process, which strongly affects its intrinsic electrical properties and limits the doping efficiency by adsorption. Here, we introduce a facile dry-cleaning method based on UV irradiation to eliminate the organic residues even after device fabrication. Through surface topography, Raman analysis, and electrical transport measurement characteristics, we confirm that the optimized UV treatment can recover the clean graphene surface and improve graphene-FET performance more effectively than thermal treatment. We propose our UV irradiation method as a systematically controllable and damage-free post process for application in large-area devices.

McClean Lake. Site Guide

International Nuclear Information System (INIS)

2016-09-01

Located over 700 kilometers northeast of Saskatoon, Areva's McClean Lake site is comprised of several uranium mines and one of the most technologically advanced uranium mills in the world - the only mill designed to process high-grade uranium ore without dilution. Areva has operated several open-pit uranium mines at the McClean Lake site, and is evaluating future mines at and near the site. The McClean Lake mill has recently undergone a multimillion-dollar upgrade and expansion, which has doubled its annual production capacity of uranium concentrate to 24 million pounds. It is the only facility in the world capable of processing high-grade uranium ore without diluting it. The mill processes the ore from the Cigar Lake mine, the world's second largest and highest-grade uranium mine. The McClean Lake site operates 365 days a year on a week-in/week-out rotation schedule for workers, over 50% of whom reside in northern Saskatchewan communities. Tailings are waste products resulting from milling uranium ore. This waste is made up of leach residue solids, waste solutions and chemical precipitates that are carefully engineered for long-term disposal. The TMF serves as the repository for all resulting tailings. This facility allows proper waste management, which minimizes potential adverse environmental effects. Mining projections indicate that the McClean Lake mill will produce tailings in excess of the existing capacity of the TMF. After evaluating a number of options, Areva has decided to pursue an expansion of this facility. Areva is developing the Surface Access Borehole Resource Extraction (SABRE) mining method, which uses a high-pressure water jet placed at the bottom of the drill hole to extract ore. Areva has conducted a series of tests with this method and is evaluating its potential for future mining operations. McClean Lake maintains its certification in ISO 14001 standards for environmental management and OHSAS 18001 standards for occupational health

A novel compound cleaning solution for benzotriazole removal after copper CMP

International Nuclear Information System (INIS)

Gu Zhangbing; Liu Yuling; Gao Baohong; Wang Chenwei; Deng Haiwen

2015-01-01

After the chemical mechanical planarization (CMP) process, the copper surface is contaminated by a mass of particles (e.g. silica) and organic residues (e.g. benzotriazole), which could do great harm to the integrated circuit, so post-CMP cleaning is essential. In particular, benzotriazole (BTA) forms a layer of Cu-BTA film with copper on the surface, which leads to a hydrophobic surface of copper. So an effective cleaning solution is needed to remove BTA from the copper surface. In this work, a new compound cleaning solution is designed to solve two major problems caused by BTA: one is removing BTA and the other is copper surface corrosion that is caused by the cleaning solution. The cleaning solution is formed of alkaline chelating agent (FA/O II type), which is used to remove BTA, and a surfactant (FA/O I type), which is used as a corrosion inhibitor. BTA removal is characterized by contact angle measurements and electrochemical techniques. The inhibiting corrosion ability of the surfactant is also characterized by electrochemical techniques. The proposed compound cleaning solution shows advantages in removing BTA without corroding the copper surface. (paper)

Effects of physical and chemical aspects on membrane fouling and cleaning using interfacial free energy analysis in forward osmosis.

Science.gov (United States)

Zhang, Wanzhu; Dong, Bingzhi

2018-05-20

Natural organic matter (NOM) in micro-polluted water purification using membranes is a critical issue to handle. Understanding the fouling mechanism in the forward osmosis (FO) process, particularly identifying the predominant factor that controls membrane fouling, could have significant effects on exerting the advantages of FO technique. Cellulose triacetate no-woven (CTA-NW) membrane is applied to experiments with a high removal efficiency (> 99%) for the model foulant. Tannic acid (TA) is used as a surrogate foulant for NOM in the membrane fouling process, thus enabling the analysis of the effects of physical and chemical aspects of water flux, retention, and adsorption. The membrane fouling behavior is affected mainly by the combined effects of the osmotic dragging force and the interaction of the pH in the working solution, foulants, and calcium ions, as demonstrated by the water flux loss and the changes of membrane retention and adsorption. The fouled CTA-NW membrane (in PRO mode) could be flux-recovered by > 85% through physical cleaning methods. The interfacial free energy analysis theory was used to analyze the membrane fouling behavior with calculating the interfacial cohesion and adhesion free energies. The cohesion free energy refers to the deposition of foulants (TA or TA combined with calcium ions) on a fouled membrane. In addition, the adhesion free energy could be used to evaluate the interaction between foulants and a clean membrane.

Reducing hazardous cleaning product use: a collaborative effort.

Science.gov (United States)

Pechter, Elise; Azaroff, Lenore S; López, Isabel; Goldstein-Gelb, Marcy

2009-01-01

Workplace hazards affecting vulnerable populations of low-wage and immigrant workers present a special challenge to the practice of occupational health. Unions, Coalition for Occupational Safety and Health (COSH) groups, and other organizations have developed worker-led approaches to promoting safety. Public health practitioners can provide support for these efforts. This article describes a successful multiyear project led by immigrant cleaning workers with their union, the Service Employees International Union (SEIU) Local 615, and with support from the Massachusetts COSH (MassCOSH) to address exposure to hazardous chemicals. After the union had identified key issues and built a strategy, the union and MassCOSH invited staff from the Massachusetts Department of Public Health's Occupational Health Surveillance Program (OHSP) to provide technical information about health effects and preventive measures. Results included eliminating the most hazardous chemicals, reducing the number of products used, banning mixing products, and improving safety training. OHSP's history of public health practice regarding cleaning products enabled staff to respond promptly. MassCOSH's staff expertise and commitment to immigrant workers allowed it to play a vital role.

Laser cleaning of sulfide scale on compressor impeller blade

International Nuclear Information System (INIS)

Tang, Q.H.; Zhou, D.; Wang, Y.L.; Liu, G.F.

2015-01-01

Highlights: • The effects of sulfide layers and fluence values on the mechanism of laser cleaning were experimentally established. • The specimen surface with sulfide scale becomes slightly smoother than that before laser cleaning. • The mechanism of laser cleaning the sulfide scale of stainless steel is spallation without oxidization. • It would avoid chemical waste and dust pollution using a fiber laser instead of using nitric acids or sandblasting. - Abstract: Sulfide scale on the surface of a compressor impeller blade can considerably reduce the impeller performance and its service life. To prepare for subsequent remanufacturing, such as plasma spraying, it needs to be removed completely. In the corrosion process on an FV(520)B stainless steel, sulfide scale is divided into two layers because of different outward diffusion rates of Cr, Ni and Fe. In this paper, the cleaning threshold values of the upper and inner layers and the damage threshold value of the substrate were investigated using a pulsed fiber laser. To obtain experimental evidence, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and 3D surface profilometry were employed to investigate the two kinds of sulfide layers on specimens before, during, and after laser cleaning.

(Preoxidation cleaning optimization for crystalline silicon)

Energy Technology Data Exchange (ETDEWEB)

1991-01-01

A series of controlled experiments has been performed in Sandia's Photovoltaic Device Fabrication Laboratory to evaluate the effect of various chemical surface treatments on the recombination lifetime of crystalline silicon wafers subjected to a high-temperature dry oxidation. From this series of experiments we have deduced a relatively simple yet effective cleaning sequence. We have also evaluated the effect of different chemical damage-removal etches for improving the recombination lifetime and surface smoothness of mechanically lapped wafers. This paper presents the methodology used, the experimental results obtained, and our experience with using this process on a continuing basis over a period of many months. 7 refs., 4 figs., 1 tab.

Cleaning the soil

International Nuclear Information System (INIS)

Stegmann, R.

1993-01-01

Volume 6 of the Hamburg Reports contains contributions from scientists from the Special Research Field 188 'Cleaning up Contaminated Soils' of the Technical University of Hamburg-Harburg and the University of Hamburg and of experts from science and from the practical field. The soil science and analytical aspects of the biological and chemical/physical treatment processes are shown and open questions specific to processes are dealt with. Scientific results are compared with practical experience here. The evaluation of treated soils for reuse in the environment is a very important question, which is explained in the first articles here. Examples of case studies are shown in the last part of the volume. (orig.) [de

Carbon Dioxide Nucleation as a Novel Cleaning Method for Sodium Alginate Fouling Removal from Reverse Osmosis Membranes desalination

KAUST Repository

Alnajjar, Heba

2017-01-01

in foulants aggregates formation. Although there are some physical techniques that can maintain the membrane performance without reducing its lifetime, only chemical cleanings are still commonly used in RO plants. In this study, a novel cleaning method

TCV mirrors cleaned by plasma

Directory of Open Access Journals (Sweden)

L. Marot

2017-08-01

Full Text Available Metallic mirrors exposed in TCV tokamak were cleaned by plasma in laboratory. A gold (Au mirror was deposited with 185–285nm of amorphous carbon (aC:D film coming from the carbon tiles of TCV. Another molybdenum (Mo mirror had a thicker deposit due to a different location within the tokamak. The thickness measurements were carried out using ellipsometry and the reflectivity measurements performed by spectrophotometry revealed a decrease of the specular reflectivity in the entire range (250–2500nm for the Mo mirror and specifically in the visible spectrum for the Au. Comparison of the simulated reflectivity using a refractive index of 1.5 and a Cauchy model for the aC:D gives good confidence on the estimated film thickness. Plasma cleaning using radio frequency directly applied to a metallic plate where the mirrors were fixed demonstrated the ability to remove the carbon deposits. A mixture of 50% hydrogen and 50% helium was used with a −200V self-bias. Due to the low sputtering yield of He and the low chemical erosion of hydrogen leading to volatile molecules, 20h of cleaning were needed for Au mirror and more than 60h for Mo mirror. Recovery of the reflectivity was not complete for the Au mirror most likely due to damage of the surface during tokamak exposure (breakdown phenomena.

Hard surface biocontrol in hospitals using microbial-based cleaning products.

Directory of Open Access Journals (Sweden)

Alberta Vandini

Full Text Available Healthcare-Associated Infections (HAIs are one of the most frequent complications occurring in healthcare facilities. Contaminated environmental surfaces provide an important potential source for transmission of many healthcare-associated pathogens, thus indicating the need for new and sustainable strategies.This study aims to evaluate the effect of a novel cleaning procedure based on the mechanism of biocontrol, on the presence and survival of several microorganisms responsible for HAIs (i.e. coliforms, Staphyloccus aureus, Clostridium difficile, and Candida albicans on hard surfaces in a hospital setting.The effect of microbial cleaning, containing spores of food grade Bacillus subtilis, Bacillus pumilus and Bacillus megaterium, in comparison with conventional cleaning protocols, was evaluated for 24 weeks in three independent hospitals (one in Belgium and two in Italy and approximately 20000 microbial surface samples were collected.Microbial cleaning, as part of the daily cleaning protocol, resulted in a reduction of HAI-related pathogens by 50 to 89%. This effect was achieved after 3-4 weeks and the reduction in the pathogen load was stable over time. Moreover, by using microbial or conventional cleaning alternatively, we found that this effect was directly related to the new procedure, as indicated by the raise in CFU/m2 when microbial cleaning was replaced by the conventional procedure. Although many questions remain regarding the actual mechanisms involved, this study demonstrates that microbial cleaning is a more effective and sustainable alternative to chemical cleaning and non-specific disinfection in healthcare facilities.This study indicates microbial cleaning as an effective strategy in continuously lowering the number of HAI-related microorganisms on surfaces. The first indications on the actual level of HAIs in the trial hospitals monitored on a continuous basis are very promising, and may pave the way for a novel and cost

Hard surface biocontrol in hospitals using microbial-based cleaning products.

Science.gov (United States)

Vandini, Alberta; Temmerman, Robin; Frabetti, Alessia; Caselli, Elisabetta; Antonioli, Paola; Balboni, Pier Giorgio; Platano, Daniela; Branchini, Alessio; Mazzacane, Sante

2014-01-01

Healthcare-Associated Infections (HAIs) are one of the most frequent complications occurring in healthcare facilities. Contaminated environmental surfaces provide an important potential source for transmission of many healthcare-associated pathogens, thus indicating the need for new and sustainable strategies. This study aims to evaluate the effect of a novel cleaning procedure based on the mechanism of biocontrol, on the presence and survival of several microorganisms responsible for HAIs (i.e. coliforms, Staphyloccus aureus, Clostridium difficile, and Candida albicans) on hard surfaces in a hospital setting. The effect of microbial cleaning, containing spores of food grade Bacillus subtilis, Bacillus pumilus and Bacillus megaterium, in comparison with conventional cleaning protocols, was evaluated for 24 weeks in three independent hospitals (one in Belgium and two in Italy) and approximately 20000 microbial surface samples were collected. Microbial cleaning, as part of the daily cleaning protocol, resulted in a reduction of HAI-related pathogens by 50 to 89%. This effect was achieved after 3-4 weeks and the reduction in the pathogen load was stable over time. Moreover, by using microbial or conventional cleaning alternatively, we found that this effect was directly related to the new procedure, as indicated by the raise in CFU/m2 when microbial cleaning was replaced by the conventional procedure. Although many questions remain regarding the actual mechanisms involved, this study demonstrates that microbial cleaning is a more effective and sustainable alternative to chemical cleaning and non-specific disinfection in healthcare facilities. This study indicates microbial cleaning as an effective strategy in continuously lowering the number of HAI-related microorganisms on surfaces. The first indications on the actual level of HAIs in the trial hospitals monitored on a continuous basis are very promising, and may pave the way for a novel and cost-effective strategy

Effects of micro- and nano-structures on the self-cleaning behaviour of lotus leaves

Science.gov (United States)

Cheng, Y. T.; Rodak, D. E.; Wong, C. A.; Hayden, C. A.

2006-03-01

When rain falls on lotus leaves water beads up with a high contact angle. The water drops promptly roll off the leaves, collecting dirt along the way. This self-cleaning ability or lotus effect has, in recent years, stimulated much research effort worldwide for a variety of applications ranging from self-cleaning window glasses, paints, and fabrics to low friction surfaces. What are the mechanisms giving rise to the lotus effect? Although chemical composition and surface structure are believed important, a systematic experimental investigation of their effects is still lacking. By altering the surface structure of the leaves while keeping their chemical composition approximately the same, we report in this study the influence of micro- and nano-scale structures on the wetting behaviour of lotus leaves. The findings of this work may help design self-cleaning surfaces and improve our understanding of wetting mechanisms.

CORAL REEF BIOLOGICAL CRITERIA: USING THE CLEAN ...

Science.gov (United States)

Coral reefs are declining at unprecedented rates worldwide due to multiple interactive stressors including climate change and land-based sources of pollution. The Clean Water Act (CWA) can be a powerful legal instrument for protecting water resources, including the biological inhabitants of coral reefs. The objective of the CWA is to restore and maintain the chemical, physical and biological integrity of water resources. Coral reef protection and restoration under the Clean Water Act begins with water quality standards - provisions of state or Federal law that consist of a designated use(s) for the waters of the United States and water quality criteria sufficient to protect the uses. Aquatic life use is the designated use that is measured by biological criteria (biocriteria). Biocriteria are expectations set by a jurisdiction for the quality and quantity of living aquatic resources in a defined waterbody. Biocriteria are an important addition to existing management tools for coral reef ecosystems. The Technical Support Document “Coral Reef Biological Criteria: Using the Clean Water Act to Protect a National Treasure” will provide a framework to aid States and Territories in their development, adoption, and implementation of coral reef biocriteria in their respective water quality standards. The Technical Support Document “Coral Reef Biological Criteria: Using the Clean Water Act to Protect a National Treasure” will provide a framework for coral re

Basic Science for a Secure Energy Future

Science.gov (United States)

Horton, Linda

2010-03-01

Anticipating a doubling in the world's energy use by the year 2050 coupled with an increasing focus on clean energy technologies, there is a national imperative for new energy technologies and improved energy efficiency. The Department of Energy's Office of Basic Energy Sciences (BES) supports fundamental research that provides the foundations for new energy technologies and supports DOE missions in energy, environment, and national security. The research crosses the full spectrum of materials and chemical sciences, as well as aspects of biosciences and geosciences, with a focus on understanding, predicting, and ultimately controlling matter and energy at electronic, atomic, and molecular levels. In addition, BES is the home for national user facilities for x-ray, neutron, nanoscale sciences, and electron beam characterization that serve over 10,000 users annually. To provide a strategic focus for these programs, BES has held a series of ``Basic Research Needs'' workshops on a number of energy topics over the past 6 years. These workshops have defined a number of research priorities in areas related to renewable, fossil, and nuclear energy -- as well as cross-cutting scientific grand challenges. These directions have helped to define the research for the recently established Energy Frontier Research Centers (EFRCs) and are foundational for the newly announced Energy Innovation Hubs. This overview will review the current BES research portfolio, including the EFRCs and user facilities, will highlight past research that has had an impact on energy technologies, and will discuss future directions as defined through the BES workshops and research opportunities.

Cleaning of road accessories with powdered sodium bicarbonate; Jutansan natrium ryu wo mochiita doro fuzokubutsu no senjo

Energy Technology Data Exchange (ETDEWEB)

Yamashita, H.; Amagori, Y.; Mori, E. [Japan Highway Public Corporation, Tokyo (Japan)

1998-06-25

A method for cleaning highway accessories with powdered sodium bicarbonate is developed, to replace mechanical cleaning by a multi-purpose vehicle or manual cleaning, and thereby to reduce road maintenance cost. It pneumatically blows sodium bicarbonate particles by a blaster connected to a water tank and compressor onto a variety of stains to remove them. The cleaning system is applicable to a variety of purposes, allowing dry and wet cleaning modes to be easily switched from each other. Sodium bicarbonate, being naturally occurring, is harmless, and its type can be freely chosen. This method was applied in FY1996 mainly to cleaning interior plates in highways, to collect the basic data. Its cleaning effectiveness has been confirmed by applying it to the internal plates, which are difficult to clean by a multi-purpose vehicle, and illuminators in tunnels, whose cleaning areas are narrow. It recovers reflectivity of plates to 85% of the initial level at the highest, and shows 3 times higher efficiency for heavily stained plates. The test was continued in FY1997. It shows an approximately 5 times higher cleaning capacity than the conventional method, greatly reducing cleaning time, especially for illuminators in tunnels. 7 figs., 5 tabs.

ANALYSIS ON TECHNOLOGICAL PROCESSES CLEANING OIL PIPELINES

Directory of Open Access Journals (Sweden)

Mariana PǍTRAŞCU

2015-05-01

Full Text Available In this paper the researches are presented concerning the technological processes of oil pipelines.We know several technologies and materials used for cleaning the sludge deposits, iron and manganese oxides, dross, stone, etc.de on the inner walls of drinking water pipes or industries.For the oil industry, methods of removal of waste materials and waste pipes and liquid and gas transport networks are operations known long, tedious and expensive. The main methods and associated problems can be summarized as follows: 1 Blowing with compressed air.2 manual or mechanical brushing, sanding with water or dry.3 Wash with water jet of high pressure, solvent or chemical solution to remove the stone and hard deposits.4 The combined methods of cleaning machines that use water jets, cutters, chains, rotary heads cutters, etc.

Influence of Dry Cleaning on the Electrical Resistance of Screen Printed Conductors on Textiles

Directory of Open Access Journals (Sweden)

Kazani Ilda

2016-09-01

Full Text Available Electrically conducting inks were screen printed on various textile substrates. The samples were dry cleaned with the usual chemicals in order to investigate the influence of the mechanical treatment on the electrical conductivity. It was found that dry cleaning has a tremendous influence on this electrical conductivity. For several samples, it is observed that the electrical resistance increases with the square of the number of dry cleaning cycles. In order to explain this observation a theoretical model and a numerical simulation have been carried out, by assuming that dry cleaning cycles introduce a crack in the conducting layer. The theoretical analysis and the numerical analysis both confirmed the experimental observations.

Effectiveness of clean-up procedures on stain susceptibility of different orthodontic adhesives

Directory of Open Access Journals (Sweden)

Swati Pundlik Mane

2014-01-01

Conclusion: Chemical-cure adhesive showed higher stain susceptibility than light-cure adhesive in all clean-up procedures. Both adhesives would show less stain susceptibility with polishing step with rubber cup and pumice.

Performances in Tank Cleaning

Directory of Open Access Journals (Sweden)

Fanel-Viorel Panaitescu

2018-03-01

Full Text Available There are several operations which must do to maximize the performance of tank cleaning. The new advanced technologies in tank cleaning have raised the standards in marine areas. There are many ways to realise optimal cleaning efficiency for different tanks. The evaluation of tank cleaning options means to start with audit of operations: how many tanks require cleaning, are there obstructions in tanks (e.g. agitators, mixers, what residue needs to be removed, are cleaning agents required or is water sufficient, what methods can used for tank cleaning. After these steps, must be verify the results and ensure that the best cleaning values can be achieved in terms of accuracy and reliability. Technology advancements have made it easier to remove stubborn residues, shorten cleaning cycle times and achieve higher levels of automation. In this paper are presented the performances in tank cleaning in accordance with legislation in force. If tank cleaning technologies are effective, then operating costs are minimal.

Genesis Solar Wind Collector Cleaning Assessment: Update on 60336 Sample Case Study

Science.gov (United States)

Goreva, Y. S.; Allums, K. K.; Gonzalez, C. P.; Jurewicz, A. J.; Burnett, D. S.; Allton, J. H.; Kuhlman, K. R.; Woolum, D.

2015-01-01

To maximize the scientific return of Genesis Solar Wind return mission it is necessary to characterize and remove a crash-derived particle and thin film surface contamination. A small subset of Genesis mission collector fragments are being subjected to extensive study via various techniques. Here we present an update on the sample 60336, a Czochralski silicon (Si-CZ) based wafer from the bulk array (B/C). This sample has undergone multiple cleaning steps (see the table below): UPW spin wash, aggressive chemical cleanings (including aqua regia, hot xylene and RCA1), as well as optical and chemical (EDS, ToF-SIMS) imaging. Contamination appeared on the surface of 60336 after the initial 2007 UPW cleaning. Aqua regia and hot xylene treatment (8/13/2013) did little to remove contaminants. The sample was UPW cleaned for the third time and imaged (9/16/13). The UPW removed the dark stains that were visible on the sample. However, some features, like "the Flounder" (a large, 100 micron feature in Fig. 1b) appeared largely intact, resisting all previous cleaning efforts. These features were likely from mobilized adhesive, derived from the Post-It notes used to stabilize samples for transport from Utah after the hard landing. To remove this contamination, an RCA step 1 organic cleaning (RCA1) was employed. Although we are still uncertain on the nature of the Flounder and why it is resistant to UPW and aqua regia/hot xylene treatment, we have found RCA1 to be suitable for its removal. It is likely that the glue from sticky pads used during collector recovery may have been a source for resistant organic contamination [9]; however [8] shows that UPW reaction with crash-derived organic contamination does not make particle removal more difficult.

Private Philanthropy and Basic Research in Mid-Twentieth Century America: The Hickrill Chemical Research Foundation.

Science.gov (United States)

Gortler, Leon; Weininger, Stephen J

2017-02-01

The Hickrill Chemical Research Foundation, located north of New York City on the estate of its patrons, Sylvan and Ruth Alice Norman Weil, had a short (1948-59) but productive life. Ruth Alice Weil received a Ph.D. in organic chemistry in 1947, directed by William von Eggers Doering of Columbia University. She intended that Hickrill contribute to cancer chemotherapy while providing resources for Doering's more speculative research. Ultimately, Doering's commitment to theoretical organic chemistry set Hickrill's research agenda. Lawrence Knox, an African American with a Harvard Ph.D., supervised the laboratory's daily activities. Hickrill's two dozen postdoctoral fellows produced path-breaking results in Hückel aromatic theory and reactive intermediate chemistry, fostering the postwar emphasis on "basic science." This essay places the Laboratory's successes in the wider context of postwar politics and scientific priorities. Private philanthropic support of basic science arose because it received little pre-World War II government support. In the immediate postwar period, modest organisations like Hickrill still met a need, but the increasing governmental defence- and non-defence-related support for science eventually rendered them unnecessary.

Decontamination of radioactive contaminated protective wear using dry cleaning solvent

International Nuclear Information System (INIS)

Muthiah, Pushpa; Chitra, S.; Paul, Biplob

2013-01-01

Liquid waste generated by conventional decontamination of radioactive contaminated cotton protective wear using detergent affects the chemical treatment of the plant. To reduce the generation of aqueous detergent waste, dry cleaning of cotton protective wear, highly soiled with oil and grease towards decontamination was tried with organic solvents. Mineral turpentine oil (MTO) among various other organic solvents was identified as a suitable organic solvent. As MTO leaves characteristic odour on the cloth, various commercial fragrances for the removal of the odour were tried. Application of the optimised dry cleaning solvent and commercial fragrance was adopted in plant scale operation. (author)

Acid leaching of coal: to produce clean fuels from Turkish lignite

Energy Technology Data Exchange (ETDEWEB)

Seferinoglu, Meryem [Mineral Research and Exploration Directorate (Turkey)], email: meryem_seferinoglu66@yahoo.com; Duzenli, Derya [Ankara Central Laboratory (Turkey)

2011-07-01

With the increasing concerns about the environment, energy producers and governments are looking at developing clean energy sources. However, Turkey has limited clean energy resources and is using low grade coal which has high sulphur content as an alternative energy source. The aim of this paper is to study the possibility of generating clean fuel from Edirne Lignite and to get a better understanding of chemical mechanisms involved in coal leaching with hydrofluoric acid (HF) solutions. Leaching was conducted on Edirne Lignite with HF solution at ambient temperature and the effects of parameters such as reaction time and concentration of acid solutions on the process were evaluated. The optimum conditions were found and it was shown that ash levels can be reduced from 28.9% to 10.5% and the calorific value increased by 500kcal/kg with the HF leaching method. This study demonstrated that the production of clean fuel from high sulphur lignite is possible.

Clean Cities Fact Sheet

Energy Technology Data Exchange (ETDEWEB)

2004-01-01

This fact sheet explains the Clean Cities Program and provides contact information for all coalitions and regional offices. It answers key questions such as: What is the Clean Cities Program? What are alternative fuels? How does the Clean Cities Program work? What sort of assistance does Clean Cities offer? What has Clean Cities accomplished? What is Clean Cities International? and Where can I find more information?

Comparative study of pulsed laser cleaning applied to weathered marble surfaces

Energy Technology Data Exchange (ETDEWEB)

Ortiz, P., E-mail: mportcal@upo.es [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain); Antúnez, V.; Ortiz, R.; Martín, J.M. [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain); Gómez, M.A. [Instituto Andaluz de Patrimonio Histórico, Camino de los Descubrimientos s/n, 41092 Seville (Spain); Hortal, A.R.; Martínez-Haya, B. [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain)

2013-10-15

The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

Comparative study of pulsed laser cleaning applied to weathered marble surfaces

International Nuclear Information System (INIS)

Ortiz, P.; Antúnez, V.; Ortiz, R.; Martín, J.M.; Gómez, M.A.; Hortal, A.R.; Martínez-Haya, B.

2013-01-01

The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

Comparative study of pulsed laser cleaning applied to weathered marble surfaces

Science.gov (United States)

Ortiz, P.; Antúnez, V.; Ortiz, R.; Martín, J. M.; Gómez, M. A.; Hortal, A. R.; Martínez-Haya, B.

2013-10-01

The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

Aspects of cleaning environmental materials for multi-element analysis, e.g. plant samples

International Nuclear Information System (INIS)

Markert, B.

1992-01-01

Cleaning of samples is often the first step in the entire procedure of sample preparation in environmental trace element research. The question must generally be raised of whether cleaning is meaningful before chemical investigations with plant material (e.g. for the determination of transfer factors in the soil/plant system) or not (e.g. for food chain analysis in the plant/animal system). The most varied cleaning procedures for plant samples are currently available ranging from dry and wet wiping of the leaf or needle surface up to the complete removal of the cuticule with the aid of chlorofom. There is at present no standardized cleaning procedure for plant samples so that it is frequently not possible to compare analytical data from different working groups studying the same plant species. (orig.)

Laser surface cleaning

International Nuclear Information System (INIS)

Freiwald, J.G.; Freiwald, D.A.

1994-01-01

The objective of this work is a laboratory demonstration that red-lead primer and two-part epoxy paints can be stripped from concrete and metal surfaces using surface cleaning systems based on pulsed-repetition CO 2 lasers. The three goals are to: (1) demonstrate coatings removal, including surface pore cleaning; (2) demonstrate that there is negligible release of ablated contaminants to the environment; and (3) demonstrate that the process will generate negligible amounts of additional waste compared to competing technologies. Phase 1 involved site visits to RMI and Fernald to assess the cleaning issues for buildings and parts. In addition, Phase 1 included detailed designs of a more powerful system for industrial cleaning rates, including laser, articulating optics, ablated-material capture suction nozzle attached to a horizontal raster scanner for floor cleaning, and filtration system. Some concept development is also being done for using robots, and for parts cleaning. In Phase 2 a transportable 6 kW system will be built and tested, with a horizontal surface scanner for cleaning paint from floors. The laboratory tests will again be instrumented. Some concept development will continue for using robots, and for parts cleaning. This report describes Phase 1 results

Flux recovery of ceramic tubular membranes fouled with whey proteins: Some aspects of membrane cleaning

Directory of Open Access Journals (Sweden)

Popović Svetlana S.

2008-01-01

Full Text Available Efficiency of membrane processes is greatly affected by the flux reduction due to the deposits formation at the surface and/or in the pores of the membrane. Efficiency of membrane processes is affected by cleaning procedure applied to regenerate flux. In this work, flux recovery of ceramic tubular membranes with 50 and 200 nm pore size was investigated. The membranes were fouled with reconstituted whey solution for 1 hour. After that, the membranes were rinsed with clean water and then cleaned with sodium hydroxide solutions or formulated detergents (combination of P3 Ultrasil 67 and P3 Ultrasil 69. Flux recovery after the rinsing step was not satisfactory although fouling resistance reduction was significant so that chemical cleaning was necessary. In the case of 50 nm membrane total flux recovery was achieved after cleaning with 1.0% (w/w sodium hydroxide solution. In the case of 200 nm membrane total flux recovery was not achieved irrespective of the cleaning agent choice and concentration. Cleaning with commercial detergent was less efficient than cleaning with the sodium hydroxide solution.

Challenges with modifications of the McClean Lake mill to process midwest ore

International Nuclear Information System (INIS)

Nguyen, T.T.; Backham, L.

2010-01-01

Midwest is a unique uranium deposit with exceptionally high arsenic content. The ore body is located 17 km west of the McClean Lake operation. The McClean Lake mill will be modified to process Midwest ore and handle solid wastes from the Midwest water treatment plant. This paper describes the modifications required of the McClean Lake mill, process challenges associated with treatment of the arsenic, and the possibility of recovering nickel and cobalt as a by-product. It also reviews the complexity in the design of the Midwest water treatment facility which incorporates reverse osmosis technology with conventional physical-chemical water treatment. (author)

Self-Cleaning Antireflective Optical Coatings

KAUST Repository

Guldin, Stefan

2013-11-13

Low-cost antireflection coatings (ARCs) on large optical surfaces are an ingredient-technology for high-performance solar cells. While nanoporous thin films that meet the zero-reflectance conditions on transparent substrates can be cheaply manufactured, their suitability for outdoor applications is limited by the lack of robustness and cleanability. Here, we present a simple method for the manufacture of robust self-cleaning ARCs. Our strategy relies on the self-assembly of a block-copolymer in combination with silica-based sol-gel chemistry and preformed TiO2 nanocrystals. The spontaneous dense packing of copolymer micelles followed by a condensation reaction results in an inverse opal-type silica morphology that is loaded with TiO2 photocatalytic hot-spots. The very low volume fraction of the inorganic network allows the optimization of the antireflecting properties of the porous ARC despite the high refractive index of the embedded photocatalytic TiO2 nanocrystals. The resulting ARCs combine high optical and self-cleaning performance and can be deposited onto flexible plastic substrates. © 2013 American Chemical Society.

Ultra-clean

International Nuclear Information System (INIS)

Hergenroether, K.

1987-01-01

No other method guarantees such a thorough cleaning of contaminated materials' surfaces. Only ultrasound can reach those cavities crevices and corners where any manual cleaning fails. Furthermore there is no cumbersome and time-consuming manual decontamination which often has to be carried out in glove boxes and hot cells. Depending on the design the cleaning effect can reach from removing adhering dirt particles to removing complete surface layers. (orig./PW) [de

Clean Energy Solutions Center: Assisting Countries with Clean Energy Policy

Science.gov (United States)

advice on financing instruments. In a recent keynote to the Climate and Clean Energy Investment Forum renewable energy technologies in the country. Informing Energy Access and Clean Energy Project Finance understanding and knowledge of how to design policies that enable financing and encourage investment in clean

Chemical pneumonitis

Science.gov (United States)

... cleaning materials such as chlorine bleach, during industrial accidents, or near swimming pools) Grain and fertilizer dust ... and the A.D.A.M. Editorial team. Chemical Emergencies ... about A.D.A.M.'s editorial policy , editorial process and privacy policy . A.D.A.M. is ...

Post-CMP cleaning for metallic contaminant removal by using a remote plasma and UV/ozone

International Nuclear Information System (INIS)

Lim, Jong Min; Jeon, Bu Yong; Lee, Chong Mu

2000-01-01

For the chemical mechanical polishing (CMP) process to be successful, it is important to establish a good post-CMP cleaning process that will remove not only slurry and particles but also metallic impurities from the polished surface. The common metallic contaminants found after oxide CMP and Cu CMP include Cu, K, and Fe. Scrubbing, a popular method for post-CMP cleaning, is effective in removing particles, but removal of metallic contaminants using this method is not so effective. In this study, the removal of Fe metallic contaminants like Fe, which are commonly found on the wafer surface after CMP processes, was investigated using remote-hydrogen-plasma and UV/O 3 cleaning techniques. Our results show that metal contaminants, including Fe, can be effectively removed by using a hydrogen-plasma or UV/O 3 cleaning technique performed under optimal process conditions. In remote plasma H 2 cleaning, contaminant removal is enhanced with decreasing plasma exposure time and increasing rf-power. The optimal process condition for the removal of the Fe impurities existing on the wafer surface is an rf-power of 100 W. Plasma cleaning for 5 min or less is effective in removing Fe contaminants, but a plasma exposure time of 1 min is more appropriate than 5 min in view of the process time, The surface roughness decreased by 30∼50 % after remote-H 2 -plasma cleaning. On the other hand, the highest efficiency of Fe-impurity removal was achieved for an UV exposure time of 30 s. The removal mechanism for the Fe contaminants in the remote-H 2 -plasma and the UV/O 3 cleaning processes is considered to be the liftoff of Fe atoms when the SiO is removed by evaporation after the chemical or native SiO 2 formed underneath the metal atoms reacts with H + and e - to form SiO

Evaluating exposure of pedestrians to airborne contaminants associated with non-potable water use for pavement cleaning.

Science.gov (United States)

Seidl, M; Da, G; Ausset, P; Haenn, S; Géhin, E; Moulin, L

2016-04-01

Climate change and increasing demography press local authorities to look after affordable water resources and replacement of drinking water for city necessities like street and pavement cleaning by more available raw water. Though, the substitution of drinking by non-drinking resources demands the evaluation of sanitary hazards. This article aims therefore to evaluate the contribution of cleaning water to the overall exposure of city dwellers in case of wet pavement cleaning using crossed physical, chemical and biological approaches. The result of tracer experiments with fluorescein show that liquid water content of the cleaning aerosol produced is about 0.24 g m(-3), rending possible a fast estimation of exposure levels. In situ analysis of the aerosol particles indicates a significant increase in particle number concentration and particle diameter, though without change in particle composition. The conventional bacterial analysis using total coliforms as tracer suggests that an important part of the contamination is issued from the pavement. The qPCR results show a more than 20-fold increase of background genome concentration for Escherichia coli and 10-fold increase for Enterococcus but a negligible contribution of the cleaning water. The fluorescence analysis of the cleaning aerosol confirms the above findings identifying pavement surface as the major contributor to aerosol organic load. The physical, chemical and microbiological approaches used make it possible to describe accurately the cleaning bioaerosol and to identify the existence of significantly higher levels of all parameters studied during the wet pavement cleaning. Though, the low level of contamination and the very short time of passage of pedestrian in the zone do not suggest a significant risk for the city dwellers. As the cleaning workers remain much longer in the impacted area, more attention should be paid to their chronic exposure.

Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: a novel platform for eco-friendly biofouling mitigation.

Science.gov (United States)

Wibisono, Yusuf; Yandi, Wetra; Golabi, Mohsen; Nugraha, Roni; Cornelissen, Emile R; Kemperman, Antoine J B; Ederth, Thomas; Nijmeijer, Kitty

2015-03-15

Biofouling is still a major challenge in the application of nanofiltration and reverse osmosis membranes. Here we present a platform approach for environmentally friendly biofouling control using a combination of a hydrogel-coated feed spacer and two-phase flow cleaning. Neutral (polyHEMA-co-PEG10MA), cationic (polyDMAEMA) and anionic (polySPMA) hydrogels have been successfully grafted onto polypropylene (PP) feed spacers via plasma-mediated UV-polymerization. These coatings maintained their chemical stability after 7 days incubation in neutral (pH 7), acidic (pH 5) and basic (pH 9) environments. Anti-biofouling properties of these coatings were evaluated by Escherichia coli attachment assay and nanofiltration experiments at a TMP of 600 kPag using tap water with additional nutrients as feed and by using optical coherence tomography. Especially the anionic polySPMA-coated PP feed spacer shows reduced attachment of E. coli and biofouling in the spacer-filled narrow channels resulting in delayed biofilm growth. Employing this highly hydrophilic coating during removal of biofouling by two-phase flow cleaning also showed enhanced cleaning efficiency, feed channel pressure drop and flux recoveries. The strong hydrophilic nature and the presence of negative charge on polySPMA are most probably responsible for the improved antifouling behavior. A combination of polySPMA-coated PP feed spacers and two-phase flow cleaning therefore is promising and an environmentally friendly approach to control biofouling in NF/RO systems employing spiral-wound membrane modules. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficient methods of nanoimprint stamp cleaning based on imprint self-cleaning effect

Energy Technology Data Exchange (ETDEWEB)

Meng Fantao; Chu Jinkui [Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, 116024 Dalian (China); Luo Gang; Zhou Ye; Carlberg, Patrick; Heidari, Babak [Obducat AB, SE-20125 Malmoe (Sweden); Maximov, Ivan; Montelius, Lars; Xu, H Q [Division of Solid State Physics, Lund University, Box 118, S-22100 Lund (Sweden); Nilsson, Lars, E-mail: ivan.maximov@ftf.lth.se [Department of Food Technology, Engineering and Nutrition, Lund University, Box 117, S-22100 Lund (Sweden)

2011-05-06

Nanoimprint lithography (NIL) is a nonconventional lithographic technique that promises low-cost, high-throughput patterning of structures with sub-10 nm resolution. Contamination of nanoimprint stamps is one of the key obstacles to industrialize the NIL technology. Here, we report two efficient approaches for removal of typical contamination of particles and residual resist from stamps: thermal and ultraviolet (UV) imprinting cleaning-both based on the self-cleaning effect of imprinting process. The contaminated stamps were imprinted onto polymer substrates and after demolding, they were treated with an organic solvent. The images of the stamp before and after the cleaning processes show that the two cleaning approaches can effectively remove contamination from stamps without destroying the stamp structures. The contact angles of the stamp before and after the cleaning processes indicate that the cleaning methods do not significantly degrade the anti-sticking layer. The cleaning processes reported in this work could also be used for substrate cleaning.

How clean is clean?---How clean is needed?

International Nuclear Information System (INIS)

Hays, A.K.

1991-01-01

This paper will provide an overview of cleaning qualifications used in a variety of industries: from small-scale manufacturer's of precision-machined products to large-scale manufacturer's of electronics (printed wiring boards and surface mount technology) and microelectronics. Cleanliness testing techniques used in the production of precision-machined products, will be described. The on-going DOD program to obtain high-reliability electronics, through the use of military specifications for cleaning and cleanliness levels, will be reviewed. In addition, the continually changing cleanroom/materials standards of the microelectronics industry will be discussed. Finally, we will speculate on the role that new and improved analytical techniques and sensor technologies will play in the factories of the future. 4 refs., 1 tab

Cleaning results of new and fouled nanofiltration membrane characterized by contact angle, updated DSPM, flux and salts rejection

International Nuclear Information System (INIS)

Al-Amoudi, Ahmed; Williams, Paul; Al-Hobaib, A.S.; Lovitt, Robert W.

2008-01-01

In membrane process industries, membrane cleaning is one of the most important concerns from both economical and scientific points of view. Though cleaning is important to recover membrane performance, an inappropriate selection of cleaning agents may result into unsatisfactory cleaning or irreparable membrane. In this study the cleaning performance has been studied with measurements of membrane contact angle, Updated Donnan steric partitioning pore model (UDSPM) and salt rejection as well as flux measurement. Thin film nanofiltration (NF) membranes such as DK, HL and DL provided by GE Osmonics are used in this study. Tests were carried out with virgin DK, HL and DL as well as fouled DK membranes. Several cleaning agents were investigated; some of them were analytical grade such as HCl, NaOH and others such as SDS, mix agents were commercial grade agents that are already in use in commercial plants. Contact angle, DSPM and salt rejection as well as flux of virgin and fouled membranes before and after chemical cleaning were measured and compared. The contact angle measurements with and without chemical cleaning of different virgin and fouled membranes revealed very interesting results which may be used to characterise the membrane surface cleanliness. The contact angle results revealed that the cleaning agents are found to modify membrane surface properties (hydrophobicity/hydrophilicity) of the treated and untreated virgin and fouled membranes. The details of these results were also investigated and are reported in the paper. However, UDSPM method did not give any valuable information about pore size of the untreated and treated NF membranes. The salt rejection level of monovalent and divalent ions before and after cleaning by high and low pH cleaning agents is also investigated and is reported in the paper

Cleaning results of new and fouled nanofiltration membrane characterized by contact angle, updated DSPM, flux and salts rejection

Energy Technology Data Exchange (ETDEWEB)

Al-Amoudi, Ahmed [Centre for complex fluids processing, Multidisciplinary Nanotechnology Centre, School of Engineering, University of Wales, Swansea SA2 8PP (United Kingdom) and Saline Water Conversion Corporation (SWCC), Saline Water Desalination Research Institute Staff (Saudi Arabia)], E-mail: 310981@swan.ac.uk; Williams, Paul [Centre for complex fluids processing, Multidisciplinary Nanotechnology Centre, School of Engineering, University of Wales, Swansea SA2 8PP (United Kingdom); Al-Hobaib, A.S. [Institute of Atomic Energy Research, King Abdulaziz City for Science And Technology, P.O. Box 6086, Riyadh 11442 (Saudi Arabia); Lovitt, Robert W. [Centre for complex fluids processing, Multidisciplinary Nanotechnology Centre, School of Engineering, University of Wales, Swansea SA2 8PP (United Kingdom)

2008-04-30

In membrane process industries, membrane cleaning is one of the most important concerns from both economical and scientific points of view. Though cleaning is important to recover membrane performance, an inappropriate selection of cleaning agents may result into unsatisfactory cleaning or irreparable membrane. In this study the cleaning performance has been studied with measurements of membrane contact angle, Updated Donnan steric partitioning pore model (UDSPM) and salt rejection as well as flux measurement. Thin film nanofiltration (NF) membranes such as DK, HL and DL provided by GE Osmonics are used in this study. Tests were carried out with virgin DK, HL and DL as well as fouled DK membranes. Several cleaning agents were investigated; some of them were analytical grade such as HCl, NaOH and others such as SDS, mix agents were commercial grade agents that are already in use in commercial plants. Contact angle, DSPM and salt rejection as well as flux of virgin and fouled membranes before and after chemical cleaning were measured and compared. The contact angle measurements with and without chemical cleaning of different virgin and fouled membranes revealed very interesting results which may be used to characterise the membrane surface cleanliness. The contact angle results revealed that the cleaning agents are found to modify membrane surface properties (hydrophobicity/hydrophilicity) of the treated and untreated virgin and fouled membranes. The details of these results were also investigated and are reported in the paper. However, UDSPM method did not give any valuable information about pore size of the untreated and treated NF membranes. The salt rejection level of monovalent and divalent ions before and after cleaning by high and low pH cleaning agents is also investigated and is reported in the paper.

NICE3 SO3 Cleaning Process in Semiconductor Manufacturing

International Nuclear Information System (INIS)

Blazek, Steve

1999-01-01

This fact sheet explains how Anon, Inc., has developed a novel method of removing photoresist--a light-sensitive material used to produce semiconductor wafers for computers--from the computer manufacturing process at reduced cost and greater efficiency. The new technology is technically superior to existing semiconductor cleaning methods and results in reduced use of hazardous chemicals

Short communication: Reactivity of diacetyl with cleaning and sanitizing agents.

Science.gov (United States)

Rincon-Delgadillo, M I; Lopez-Hernandez, A; Rankin, S A

2013-01-01

Diacetyl is used to impart a buttery flavor to numerous food products such as sour cream, cottage cheese, vegetable oil-based spreads, baked goods, and beverages. Recent studies have linked exposure to high concentrations of diacetyl and the onset of bronchiolitis obliterans. Due to the reported risks that diacetyl may pose, many food companies have altered practices to reduce worker exposure to diacetyl, including the use of personal respirators, improved air handling systems, and adequate cleaning practices. Commonly used cleaning and sanitizing agents may be reactive with diacetyl; however, the efficacy of these chemicals has not been studied in detail and remains unclear. The objective of this work was to study the reaction chemistry of diacetyl with common industrial cleaning and sanitizing chemicals. The reactions were assessed at equimolar concentrations and analyzed by gas chromatography-mass spectrometry. Peroxyacetic acid was most reactive with diacetyl (95% reduction in diacetyl), followed by sodium hypochlorite (76% reduction), and hydrogen peroxide (26% reduction). Benzalkonium chloride (BAC) did not react with diacetyl. Acetic acid was detected as the main product of reactions of diacetyl with peroxyacetic acid, sodium hypochlorite, and hydrogen peroxide. 1,1-Dichloro-2-propanone and 1,1,1-trichloropropanone were also identified as volatile reaction products in the sodium hypochlorite reactions. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Meet the biologists: Sour gas treatment uses biology rather than chemistry to clean things up

Energy Technology Data Exchange (ETDEWEB)

Budd, G.

2003-03-01

Basic elements of the new bio-desulfurization technology are described. The new process uses the commonly occurring bacterium, Thiobacillus, rather than chemical means to remove hydrogen sulfide from natural gas. Development of the process began some ten years ago in the Netherlands as a means to clean sewage water and purify water for beer. The application of removing hydrogen sulfide from natural gas evolved upon discovery that the process was able to convert hydrogen sulfide to sulfur. Key to the bio-desulfurization process is the Thiobacillus bacterium, which unlike other plant forms, relies on chemosynthesis (instead of photosynthesis) of hydrogen sulfide, oxygen and carbon dioxide for its energy requirements. The technology has applications in refineries as well as in gas processing plants. It is well suited for use in Canada where operations tend to be on the small scale (less than 50 tonnes per day). The portable unit can be moved to another location when production at a given well drops off.

SBR treatment of tank truck cleaning wastewater: sludge characteristics, chemical and ecotoxicological effluent quality.

Science.gov (United States)

Caluwé, Michel; Dobbeleers, Thomas; Daens, Dominique; Geuens, Luc; Blust, Ronny; Dries, Jan

2017-08-02

A lab-scale activated sludge sequencing batch reactor (SBR) was used to treat tank truck cleaning (TTC) wastewater with different operational strategies (identified as different stages). The first stage was an adaptation period for the seed sludge that originated from a continuous fed industrial plant treating TTC wastewater. The first stage was followed by a dynamic reactor operation based on the oxygen uptake rate (OUR). Thirdly, dynamic SBR control based on OUR treated a daily changing influent. Lastly, the reactor was operated with a gradually shortened fixed cycle. During operation, sludge settling evolved from nearly no settling to good settling sludge in 16 days. The sludge volume index improved from 200 to 70 mL gMLSS -1 in 16 days and remained stable during the whole reactor operation. The average soluble chemical oxygen demand (sCOD) removal varied from 87.0% to 91.3% in the different stages while significant differences in the food to mass ratio were observed, varying from 0.11 (stage I) to 0.37 kgCOD.(kgMLVSS day) -1 (stage III). Effluent toxicity measurements were performed with Aliivibrio fischeri, Daphnia magna and Pseudokirchneriella subcapitata. Low sensitivity of Aliivibrio was observed. A few samples were acutely toxic for Daphnia; 50% of the tested effluent samples showed an inhibition of 100% for Pseudokirchneriella.

Elimination of nuclear device in tunnel 108K. Safety of works and ecological cleanness

International Nuclear Information System (INIS)

Andrusenko, B. A.; Kuznetsov, Yu. I.; Litvinov, B. V.; Nechai, V. Z.; Smirnov, V. Z.; Zherbina, A.N.; Kozlov, E. P.; Matuschenko, A. M.; Zhantikin, T. M.; Smagulov, S. G.; Tukhvatulin, Sh. T.

1997-01-01

This paper represents the Russian and Kazakhstan specialists activity on ND elimination located in tunnel 108K at the former Semipalatinsk test site. The completed works system which is a great realized ecologically clean project for the interests of the solution of ecological problems and environment protection at the Semipalatinsk test site, is considered successively in this paper. The special attention is paid to the measures the application of which allowed to provide the absolute observance of ecological cleanness and operation safety - expertise of radiation and ecological project safety, joint radio-ecological control before and after the ND elimination, procedures of the end ND box opening, visualization and decision on the ND state, and the coordinated physical measuring as well confirming the fact of the charge BB acting and ND elimination. The paper gives the detailed comments on the realized project decisions for the stemming complex erection the use of which provided the safe disposal and sealing of chemical BB explosion products and atomized fission materials in the end box and allowed to prevent their release into the day surface. While erecting the stemming complex the new materials of stemming and stemming work technology of principle were used. The basic experiments outcomes and argumentation of the obtained experience use during the joint work while preparing and realizing the further International Agreements on the former Semipalatinsk test site, are presented in the paper conclusion

Gas storage in porous metal-organic frameworks for clean energy applications.

Science.gov (United States)

Ma, Shengqian; Zhou, Hong-Cai

2010-01-07

Depletion of fossil oil deposits and the escalating threat of global warming have put clean energy research, which includes the search for clean energy carriers such as hydrogen and methane as well as the reduction of carbon dioxide emissions, on the urgent agenda. A significant technical challenge has been recognized as the development of a viable method to efficiently trap hydrogen, methane and carbon dioxide gas molecules in a confined space for various applications. This issue can be addressed by employing highly porous materials as storage media, and porous metal-organic frameworks (MOFs) which have exceptionally high surface areas as well as chemically-tunable structures are playing an unusual role in this respect. In this feature article we provide an overview of the current status of clean energy applications of porous MOFs, including hydrogen storage, methane storage and carbon dioxide capture.

TNO experience on sodium cleaning of large plant components by vacuum distillation

Energy Technology Data Exchange (ETDEWEB)

Smit, C Ch [MT-TNO Dept. 50-MW Sodium Component Test Facility, Hengelo (Netherlands)

1978-08-01

The Intermediate Heat Exchanger and Steam generators developed within the framework of the SNR-programme are being tested in the 50 MW Test facility at Hengelo - The Netherlands. The facility was designed and built by Neratoom, and is operated by TNO, the Dutch Organisation for Applied Scientific Research. Sodium technology work, such as reported in this paper, is done in close cooperation with Neratoom and with TNO-laboratories at Apeldoorn, where several smaller sodium rigs and other facilities are available. The operation and maintenance of a large sodium test facility and sodium rigs lead to frequent cleaning of small plant components, test sections and sampling devices. The choice of method usually depends on the size of the component and the cleaning quality needed. The results are predictable and satisfactory. For large components, however, the situation is different. Although the basic cleaning methods using alcohol and moist gas are well-known, and procedures for the cleaning of small components are available, complete cleaning of tight crevices and threaded bolds cannot be guaranteed, and consequently the requalification procedure needs to include a complete disassembly and inspection of the cleaned component. For large components this policy cannot always be followed. In those cases for instance where an in-between internal inspection is required, or where only small modifications of the test object are necessary, other possibilities have to be considered. For this reason some work has been done to develop reliable vacuum distillation procedures for large components, based on the cleaning experience with small plant components. The results of these procedures applied to large plant components are reported in this paper.

TNO experience on sodium cleaning of large plant components by vacuum distillation

International Nuclear Information System (INIS)

Smit, C.Ch.

1978-01-01

The Intermediate Heat Exchanger and Steam generators developed within the framework of the SNR-programme are being tested in the 50 MW Test facility at Hengelo - The Netherlands. The facility was designed and built by Neratoom, and is operated by TNO, the Dutch Organisation for Applied Scientific Research. Sodium technology work, such as reported in this paper, is done in close cooperation with Neratoom and with TNO-laboratories at Apeldoorn, where several smaller sodium rigs and other facilities are available. The operation and maintenance of a large sodium test facility and sodium rigs lead to frequent cleaning of small plant components, test sections and sampling devices. The choice of method usually depends on the size of the component and the cleaning quality needed. The results are predictable and satisfactory. For large components, however, the situation is different. Although the basic cleaning methods using alcohol and moist gas are well-known, and procedures for the cleaning of small components are available, complete cleaning of tight crevices and threaded bolds cannot be guaranteed, and consequently the requalification procedure needs to include a complete disassembly and inspection of the cleaned component. For large components this policy cannot always be followed. In those cases for instance where an in-between internal inspection is required, or where only small modifications of the test object are necessary, other possibilities have to be considered. For this reason some work has been done to develop reliable vacuum distillation procedures for large components, based on the cleaning experience with small plant components. The results of these procedures applied to large plant components are reported in this paper

Human and Environmental Toxicity of Sodium Lauryl Sulfate (SLS): Evidence for Safe Use in Household Cleaning Products.

Science.gov (United States)

Bondi, Cara Am; Marks, Julia L; Wroblewski, Lauren B; Raatikainen, Heidi S; Lenox, Shannon R; Gebhardt, Kay E

2015-01-01

Environmental chemical exposure is a major concern for consumers of packaged goods. The complexity of chemical nomenclature and wide availability of scientific research provide detailed information but lends itself to misinterpretation by the lay person. For the surfactant sodium lauryl sulfate (SLS), this has resulted in a misunderstanding of the environmental health impact of the chemical and statements in the media that are not scientifically supported. This review demonstrates how scientific works can be misinterpreted and used in a manner that was not intended by the authors, while simultaneously providing insight into the true environmental health impact of SLS. SLS is an anionic surfactant commonly used in consumer household cleaning products. For decades, this chemical has been developing a negative reputation with consumers because of inaccurate interpretations of the scientific literature and confusion between SLS and chemicals with similar names. Here, we review the human and environmental toxicity profiles of SLS and demonstrate that it is safe for use in consumer household cleaning products.

Laser cleaning of parchment: structural, thermal and biochemical studies into the effect of wavelength and fluence

International Nuclear Information System (INIS)

Kennedy, Craig J.; Vest, Marie; Cooper, Martin; Wess, Tim J.

2004-01-01

Laser cleaning of parchment is a novel technique that has the potential to provide contactless, chemical-free cleaning of historically important documents. However, the effect of laser cleaning on the collagenous structure of parchment is still poorly understood, as is the effect of the wavelength or the energy density (fluence level) used to clean parchment. In this study, small angle X-ray scattering (SAXS), shrinkage temperature (Ts) measurements by the micro hot table technique and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of parchment samples after laser cleaning reveal the effect of cleaning to the structural, thermal and molecular characteristics of parchment, respectively. The effect of cleaning at infrared (1064 nm), green (532 nm) and ultraviolet (266 nm) wavelengths at a range of fluence levels is investigated. SAXS is used to investigate the removal of dirt from parchment. Laser cleaning at IR or green wavelengths appears not to alter the collagen diffraction pattern from SAXS, the shrinkage activity or shrinkage temperature from Ts measurements or the molecular integrity of parchment as shown by SDS-PAGE. However, parchments cleaned at the ultraviolet wavelength display structural damage and a reduction in hydrothermal stability and molecular integrity

MgB2 thin films by hybrid physical-chemical vapor deposition

International Nuclear Information System (INIS)

Xi, X.X.; Pogrebnyakov, A.V.; Xu, S.Y.; Chen, K.; Cui, Y.; Maertz, E.C.; Zhuang, C.G.; Li, Qi; Lamborn, D.R.; Redwing, J.M.; Liu, Z.K.; Soukiassian, A.; Schlom, D.G.; Weng, X.J.; Dickey, E.C.; Chen, Y.B.; Tian, W.; Pan, X.Q.; Cybart, S.A.; Dynes, R.C.

2007-01-01

Hybrid physical-chemical vapor deposition (HPCVD) has been the most effective technique for depositing MgB 2 thin films. It generates high magnesium vapor pressures and provides a clean environment for the growth of high purity MgB 2 films. The epitaxial pure MgB 2 films grown by HPCVD show higher-than-bulk T c due to tensile strain in the films. The HPCVD films are the cleanest MgB 2 materials reported, allowing basic research, such as on magnetoresistance, that reveals the two-band nature of MgB 2 . The carbon-alloyed HPCVD films demonstrate record-high H c2 values promising for high magnetic field applications. The HPCVD films and multilayers have enabled the fabrication of high quality MgB 2 Josephson junctions

Clean data

CERN Document Server

Squire, Megan

2015-01-01

If you are a data scientist of any level, beginners included, and interested in cleaning up your data, this is the book for you! Experience with Python or PHP is assumed, but no previous knowledge of data cleaning is needed.

Cleaning graphene with a titanium sacrificial layer

International Nuclear Information System (INIS)

Joiner, C. A.; Roy, T.; Hesabi, Z. R.; Vogel, E. M.; Chakrabarti, B.

2014-01-01

Graphene is a promising material for future electronic applications and chemical vapor deposition of graphene on copper is a promising method for synthesizing graphene on the wafer scale. The processing of such graphene films into electronic devices introduces a variety of contaminants which can be difficult to remove. An approach to cleaning residues from the graphene channel is presented in which a thin layer of titanium is deposited via thermal e-beam evaporation and immediately removed. This procedure does not damage the graphene as evidenced by Raman spectroscopy, greatly enhances the electrical performance of the fabricated graphene field effect transistors, and completely removes the chemical residues from the surface of the graphene channel as evidenced by x-ray photoelectron spectroscopy.

High-resolution clean-sc

NARCIS (Netherlands)

Sijtsma, P.; Snellen, M.

2016-01-01

In this paper a high-resolution extension of CLEAN-SC is proposed: HR-CLEAN-SC. Where CLEAN-SC uses peak sources in “dirty maps” to define so-called source components, HR-CLEAN-SC takes advantage of the fact that source components can likewise be derived from points at some distance from the peak,

Efficiancy of hydrogen peroxide for cleaning production areas and equipments in the radiopharmaceutical production

Energy Technology Data Exchange (ETDEWEB)

Baptista, Tatyana S.; Batista, Vanessa; Gomes, Antonio; Matsuda, Margareth; Fukumori, Neuza; Araujo, Elaine B. de, E-mail: tsbaptista@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

A great challenge in the radiopharmaceuticals production is to fulfill the Good Manufacturing Practices (GMPs), involving the validation of process and of all supporting activities such as cleaning and sanitization. The increasingly strict requirements for quality assurance system, with several norms and normative resolutions has led to a constant concern with programs and cleaning validation in pharmaceutical production. The main goal of GMP is to reduce risks inherent to pharmaceutical production, that is to reduce product contamination with microorganisms and cross-contamination. The basic requirements to prevent contamination is the development and implementation of efficient cleaning programs. In the case of clean rooms for the production of injectable radiopharmaceuticals, the requirement for cleaning programs is evidently higher due to the characteristics of these areas with hot cells for radioactive materials, where sterile radiopharmaceuticals are manipulated and distributed before administration to patients just after minutes or hours of its preparation. In the Radiopharmacy Department at IPEN it was established a cleaning program for clean rooms and hot cells using a hydrogen peroxide solution (20% proxitane alfa). The objective of this work was to assess effectiveness of this cleaning agent in reducing and/or eliminating microbial load in the clean rooms and equipment to acceptable levels in accordance with the current legislation. The analysis was conducted using results of the environmental monitoring program with and settling contact plates in clean rooms after the cleaning procedures. Furthermore, it was possible to evaluate the action of the sanitizing agent on the microbial population on the surface of equipment and clean rooms. It was also evaluated the best way to accomplish the cleaning program considering the dosimetric factor in each production process, as the main concern of pharmaceutical companies is the microbiological contamination, in

Efficiancy of hydrogen peroxide for cleaning production areas and equipments in the radiopharmaceutical production

International Nuclear Information System (INIS)

Baptista, Tatyana S.; Batista, Vanessa; Gomes, Antonio; Matsuda, Margareth; Fukumori, Neuza; Araujo, Elaine B. de

2013-01-01

A great challenge in the radiopharmaceuticals production is to fulfill the Good Manufacturing Practices (GMPs), involving the validation of process and of all supporting activities such as cleaning and sanitization. The increasingly strict requirements for quality assurance system, with several norms and normative resolutions has led to a constant concern with programs and cleaning validation in pharmaceutical production. The main goal of GMP is to reduce risks inherent to pharmaceutical production, that is to reduce product contamination with microorganisms and cross-contamination. The basic requirements to prevent contamination is the development and implementation of efficient cleaning programs. In the case of clean rooms for the production of injectable radiopharmaceuticals, the requirement for cleaning programs is evidently higher due to the characteristics of these areas with hot cells for radioactive materials, where sterile radiopharmaceuticals are manipulated and distributed before administration to patients just after minutes or hours of its preparation. In the Radiopharmacy Department at IPEN it was established a cleaning program for clean rooms and hot cells using a hydrogen peroxide solution (20% proxitane alfa). The objective of this work was to assess effectiveness of this cleaning agent in reducing and/or eliminating microbial load in the clean rooms and equipment to acceptable levels in accordance with the current legislation. The analysis was conducted using results of the environmental monitoring program with and settling contact plates in clean rooms after the cleaning procedures. Furthermore, it was possible to evaluate the action of the sanitizing agent on the microbial population on the surface of equipment and clean rooms. It was also evaluated the best way to accomplish the cleaning program considering the dosimetric factor in each production process, as the main concern of pharmaceutical companies is the microbiological contamination, in

Clean coal technologies in Japan: technological innovation in the coal industry

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-12-15

This brochure reviews the history clean coal technologies (CCT) in Japan and systematically describes the present state of CCT insofar. The brochure contains three parts. Part 1. CCT classifications; Part 2. CCT overview; and Part 3. Future outlook for CCT. The main section is part 2 which includes 1) technologies for coal resources development; 2) coal-fired power generation technologies - combustion technologies and gasification technologies; 3) iron making and general industry technologies; 4) multi-purpose coal utilization technologies - liquefaction technologies, pyrolysis technologies, powdering, fluidization, and co-utilisation technologies, and de-ashing and reforming technologies; 5) Environmental protection technologies - CO{sub 2} recovery technologies; flue gas treatment and gas cleaning technologies, and technologies to effectively use coal has; 6) basic technologies for advanced coal utilization; and 7) co-production systems.

The influence of in situ argon cleaning of GaAs on Schottky diodes and metal-semiconductor field-effect transistors

NARCIS (Netherlands)

Hassel, van J.G.; Heyker, H.C.; Kwaspen, J.J.M.

1995-01-01

The influence of in situ argon cleaning of GaAs on the electrical characteristics of Schottky diodes and metal–semiconductor field-effect transistors (MESFETs) is investigated. The beam energy was varied from 50 to 500 eV and the characteristics were compared to wet chemically cleaned devices. The

Controlling the clean room atmosphere

International Nuclear Information System (INIS)

Meeks, R.F.

1979-01-01

Several types of clean rooms are commonly in use. They include the conventional clean room, the horizontal laminar flow clean room, the vertical laminar flow clean room and a fourth type that incorporates ideas from the previous types and is known as a clean air bench or hood. These clean rooms are briefly described. The origin of contamination and methods for controlling the contamination are discussed

Dynamic analysis of the CRBRP clean-up system (three stage aqueous scrubber)

International Nuclear Information System (INIS)

Kyi, R.; Bijlani, C.; Fazekas, P.; Dajani, A.

1981-01-01

The CRBRP containment clean-up system design required the determination of the thermal-hydraulic performance of the system during its projected operating cycle. The reduced scale component tests at HEDL provided valuable information about the generic performance of the components; however, due to the limitations of the test facility the exact simulation of the actual CRBRP conditions was not feasible. A computer program was developed to permit dynamic system analysis of the full size air cleaning system. The dynamic system analysis considered the mass and energy balances across each component. In addition to the major filtration system components, the system modeling included the supporting fluid system components such as pumps, tanks and heat exchangers. Variable gas flow, temperature, chemical concentrations, and other system parameters were also modeled. Fission product heat, chemical reaction heat and heat of solution were considered. The analysis results provided sodium hydroxide solution concentrations and temperatures, gas temperatures and other variables at the various components within the air cleaning system for each calculated time interval. The accuracy of the computer modeling was verified by comparing the calculated results with HEDL test data. The comparison indicated a better than +-10% agreement with the test data. The analysis results provided the basis for the selection of the system components

Digital processing of SEM images for the assessment of evaluation indexes of cleaning interventions on Pentelic marble surfaces

International Nuclear Information System (INIS)

Moropoulou, A.; Delegou, E.T.; Vlahakis, V.; Karaviti, E.

2007-01-01

In this work, digital processing of scanning-electron-microscopy images utilized to assess cleaning interventions applied on the Pentelic marble surfaces of the National Archaeological Museum and National Library in Athens, Greece. Beside mineralogical and chemical characterization that took place by scanning-electron-microscopy with Energy Dispersive X-ray Spectroscopy, the image-analysis program EDGE was applied for estimating three evaluation indexes of the marble micro-structure. The EDGE program was developed by the U.S. Geological Survey for the evaluation of cleaning interventions applied on Philadelphia City Hall. This computer program analyzes scanning-electron-microscopy images of stone specimens cut in cross-section for measuring the fractal dimension of the exposed surfaces, the stone near-surface fracture density, the shape factor (a surface roughness factor) and the friability index which represents the physico-chemical and physico-mechanical stability of the stone surface. The results indicated that the evaluation of the marble surface micro-structure before and after cleaning is achieved by the suggested indexes, while the performance of cleaning interventions on the marble surfaces can be assessed

An Atmospheric Atomic Oxygen Source for Cleaning Smoke Damaged Art Objects

Science.gov (United States)

Banks, Bruce A.; Rutledge, Sharon K.; Norris, Mary Jo

1998-01-01

Soot and other carbonaceous combustion products deposited on the surfaces of porous ceramic, stone, ivory and paper can be difficult to remove and can have potentially unsatisfactory results using wet chemical and/or abrasive cleaning techniques. An atomic oxygen source which operates in air at atmospheric pressure, using a mixture of oxygen and helium, has been developed to produce an atomic oxygen beam which is highly effective in oxidizing soot deposited on surfaces by burning candles made of paraffin, oil or rendered animal fat. Atomic oxygen source operating conditions and the results of cleaning soot from paper, gesso, ivory, limestone and water color-painted limestone are presented,

Basis of the detection, assessment and cleaning up of sites contaminated with heavy metals

International Nuclear Information System (INIS)

Calmano, W.; Foerstner, U.

1993-01-01

The cleaning up of sites contaminated with heavy metals is still in its infancy. Depending on the type and extent of the contamination, new methods of treatment must be developed and matched to each situation. A survey is given of the groundwater contamination of soil heavy metals; the binding, availability and mobilisation of heavy metals; geo-chemical concepts for sites contaminated by heavy metals; judging the potential danger; safety measures; cleaning up processes and the reinstatement and renaturing of the soil. (orig.) [de

Solar photocatalytic cleaning of polluted water. Solare Reinigung verschmutzter Waesser mittels Photokatalyse

Energy Technology Data Exchange (ETDEWEB)

Bockelmann, D

1994-01-01

Alternatively to biological, physical and chemical methods of waste water cleaning, photocatalysis can be employed. In this residue-free method, titanium dioxide particles are brought into contact with polluted water as photocatalysts. Under UV irradiation at wave-lengths below 400 nm, change carriers are generated in the semiconductor particles that act so intensely oxidizing as to completely degrade almost all organic pollutants in waste water. In this process, the ultra-violet part of the solar spectrum can be harnessed to generate oxidation equivalents. Thus, solar photocatalytic waste water cleaning is excellently suited for developing countries. (BWI)

Comparative study of oxalic and malonic acid behaviour in the chemical cleaning of alloy 800 surfaces

International Nuclear Information System (INIS)

Garcia, Damian A.; Bruyere, Vivienne I.E.; Bordoni, Roberto A.; Olmedo, Ana M.; Morando, Pedro J.

2004-01-01

This work consisted, in a first stage, on a basic study of the dissolution mechanism of nickel ferrite in aqueous malonic acid. Powdered oxides (Ni x Fe 3-x O 4 ) were synthesized by wet procedures and heated at 750 C degrees. These oxides were characterized by conventional methods and dissolved under different experimental conditions (pH, reagent concentration, temperature, etc.) in order to determine the dissolution rates. Optimal dissolution conditions were explored and compared to the corresponding oxalic acid ones. In a second stage, these conditions were applied to oxides grown on Alloy 800 coupons. Before oxidation, all coupons were ground polished and then were exposed to hydrothermal conditions (350 C degrees, pH 25Cdegrees ≅ 10.4 -LiOH-, 20-22 days) in static autoclaves. Finally, oxidized and unoxidized coupons were treated with chemical solutions containing oxalic or malonic acid at conditions optimized in the first stage. These results were also compared to those obtained on coupons exposed to a commercial formulation, APAC (Alkaline Permanganate Ammonium Citrate), as a reference. The results on coupon descaling using APMAL (AP + Malonic), APOX (AP + oxalic) and the comparison with APAC leads to conclude that malonic acid is a reagent whose chemical behavior is much better than oxalic acid and comparable to commercial formulations. (author) [es

Petroleum storage tank cleaning using commercial microbial culture products

Energy Technology Data Exchange (ETDEWEB)

Schneider, D.R.; Entzeroth, L.C.; Timmis, A.; Whiteside, A.; Hoskins, B.C.

1995-12-31

The removal of paraffinic bottom accumulations from refinery storage tanks represents an increasingly costly area of petroleum storage management. Microorganisms can be used to reduce paraffinic bottoms by increasing the solubility of bottom material and by increasing the wax-carrying capacity of carrier oil used in the cleaning process. The economic savings of such treatments are considerable. The process is also intrinsically safer than alternative methods, as it reduces and even eliminates the need for personnel to enter the tank during the cleaning process. Both laboratory and field sample analyses can be used to document changes in tank material during the treatment process. These changes include increases in volatile content and changes in wax distribution. Several case histories illustrating these physical and chemical changes are presented along with the economics of treatment.

Alkali-assisted membrane cleaning for fouling control of anaerobic ceramic membrane bioreactor.

Science.gov (United States)

Mei, Xiaojie; Quek, Pei Jun; Wang, Zhiwei; Ng, How Yong

2017-09-01

In this study, a chemically enhanced backflush (CEB) cleaning method using NaOH solution was proposed for fouling mitigation in anaerobic membrane bioreactors (AnMBRs). Ex-situ cleaning tests revealed that NaOH dosages ranging from 0.05 to 1.30mmol/L had positive impacts on anaerobic biomass, while higher dosages (>1.30mmol/L) showed inhibition and/or toxic impacts. In-situ cleaning tests showed that anaerobic biomass could tolerate much higher NaOH concentrations due to the alkali consumption by anaerobic process and/or the buffering role of mixed liquor. More importantly, 10-20mmol-NaOH/L could significantly reduce membrane fouling rates (4-5.5 times over the AnMBR with deionized water backflush) and slightly improve methanogenic activities. COD removal efficiencies were over 87% and peaked at 20mmol-NaOH/L. However, extremely high NaOH concentration had adverse effects on filtration and treatment performance. Economic analysis indicated that 12mmol/L of NaOH was the cost-efficient and optimal fouling-control dosage for the CEB cleaning. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fundamentals and applications of dry CO2 cryogenic aerosol for photomask cleaning

Science.gov (United States)

Varghese, Ivin; Balooch, Mehdi; Bowers, Charles W.

2010-09-01

There is a dire need for the removal of all printable defects on lithography masks. As the technology node advances, smaller particles need to be efficiently removed from smaller features without any damage or adders. CO2 cryogenic aerosol cleaning is a dry, residue-free and chemically inert technique that doesn't suffer from disadvantages of conventional wet cleaning methods such as transmission/reflectivity loss, phase change, CD change, haze/progressive defects, and/or limitation on number of cleaning cycles. Ultra-pure liquid CO2 when dispensed through an optimally designed nozzle results in CO2 clusters that impart the required momentum for defect removal. Historically nanomachining debris removal has been established with this technique. Several improvements have been incorporated for cleaning of advanced node masks, which has enabled Full Mask Final Clean, a new capability that has been successfully demonstrated. The properties of the CO2 clusters can be captured utilizing the Phase Doppler Anemometry (PDA) and effect of varying process and design parameters can be verified. New nozzles have been designed to widen the cleaning process window for advanced node optical masks, without any damage to the weak primary features and/or sub-resolution assist features (SRAFs). This capability has been experimentally proven for high aspect ratio SRAFs e.g. 2.79 (52nm wide by 145 nm tall) as well as SRAFs 45nm wide by 73 nm tall. In this paper, 100% removal of soft defects that would have printed on advanced node masks is demonstrated. No printed defects larger than 50nm is observed after the CO2 cleaning. Stability of the cleaning and handling mechanisms has been demonstrated over the last 4.5 months in a production environment. The CO2 cleaning technique is expected to be effective for more advanced masks and Extreme Ultra-Violet (EUV) lithography.

Cleaning of spent solvent and method of processing cleaning liquid waste

International Nuclear Information System (INIS)

Ozawa, Masaki; Kawada, Tomio; Tamura, Nobuhiko.

1993-01-01

Spent solvents discharged from a solvent extracting step mainly comprise n-dodecane and TBP and contain nuclear fission products and solvent degradation products. The spent solvents are cleaned by using a sodium chloride free detergent comprising hydrazine oxalate and hydrazine carbonate in a solvent cleaning device. Nitric acid is added to the cleaning liquid wastes containing spent detergents extracted from the solvent cleaning device, to control an acid concentration. The detergent liquid wastes of controlled acid concentration are sent to an electrolysis oxidation bath as electrolytes and electrochemically decomposed in carbonic acid gas, nitrogen gas and hydrogen gas. The decomposed gases are processed as off gases. The decomposed liquid wastes are processed as a waste nitric acid solution. This can provide more effective cleaning. In addition, the spent detergent can be easily decomposed in a room temperature region. Accordingly, the amount of wastes can be decreased. (I.N.)

Rationale and Methods for Archival Sampling and Analysis of Atmospheric Trace Chemical Contaminants On Board Mir and Recommendations for the International Space Station

Science.gov (United States)

Perry, J. L.; James, J. T.; Cole, H. E.; Limero, T. F.; Beck, S. W.

1997-01-01

Collection and analysis of spacecraft cabin air samples are necessary to assess the cabin air quality with respect to crew health. Both toxicology and engineering disciplines work together to achieve an acceptably clean cabin atmosphere. Toxicology is concerned with limiting the risk to crew health from chemical sources, setting exposure limits, and analyzing air samples to determine how well these limits are met. Engineering provides the means for minimizing the contribution of the various contaminant generating sources by providing active contamination control equipment on board spacecraft and adhering to a rigorous material selection and control program during the design and construction of the spacecraft. A review of the rationale and objectives for sampling spacecraft cabin atmospheres is provided. The presently-available sampling equipment and methods are reviewed along with the analytical chemistry methods employed to determine trace contaminant concentrations. These methods are compared and assessed with respect to actual cabin air quality monitoring needs. Recommendations are presented with respect to the basic sampling program necessary to ensure an acceptably clean spacecraft cabin atmosphere. Also, rationale and recommendations for expanding the scope of the basic monitoring program are discussed.

Development of advanced coal cleaning process; Kodo sekitan kaishitsu gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Osaka, S [Center for Coal Utilization, Japan, Tokyo (Japan); Akimoto, A; Yamashita, T [Idemitsu Kosan Co. Ltd., Tokyo (Japan)

1996-09-01

This paper aims to develop a clean coal production process which excellently removes environmental pollutant, is low-costed, and need no particular systems for distribution of products. The result of the development was described paying attention to column flotation which is a technology to high-efficiently select particulate regions, particulate heavy media cyclone, magnetic separation, and the basic design of the process into which those above were integrated. The two-stage selection process, which is an integration of column flotation and particulate heavy media cyclone into the conventional coal preparation equipment, can produce low-ash clean coal at high separation efficiency and also suppress the rise in processing cost. This process was also effective for removal of sulfur content and trace metal elements. The use of clean coal at power plant can be effective for not only the reduction in ash treatment amount, but the aspect of boiler operation characteristics such as heat transfer efficiency of boiler furnace wall, ash related troubles, loads of electrostatic precipitator, loads of flue gas desulfurization facilities. 17 figs., 5 tabs.

Basic Soils. Revision.

Science.gov (United States)

Montana State Univ., Bozeman. Dept. of Agricultural and Industrial Education.

This curriculum guide is designed for use in teaching a course in basic soils that is intended for college freshmen. Addressed in the individual lessons of the unit are the following topics: the way in which soil is formed, the physical properties of soil, the chemical properties of soil, the biotic properties of soil, plant-soil-water…

How Do Polyethylene Glycol and Poly(sulfobetaine) Hydrogel Layers on Ultrafiltration Membranes Minimize Fouling and Stay Stable in Cleaning Chemicals?

KAUST Repository

Le, Ngoc Lieu

2017-05-18

We compare the efficiency of grafting polyethylene glycol (PEG) and poly(sulfobetaine) hydrogel layer on poly(ether imide) (PEI) hollow-fiber ultrafiltration membrane surfaces in terms of filtration performance, fouling minimization and stability in cleaning solutions. Two previously established different methods toward the two different chemistries (and both had already proven to be suited to reduce fouling significantly) are applied to the same PEI membranes. The hydrophilicity of PEI membranes is improved by the modification, as indicated by the change of contact angle value from 89° to 68° for both methods, due to the hydration layer formed in the hydrogel layers. Their pure water flux declines because of the additional permeation barrier from the hydrogel layers. However, these barriers increase protein rejection. In the exposure at a static condition, grafting PEG or poly(sulfobetaine) reduces protein adsorption to 23% or 11%, respectively. In the dynamic filtration, the hydrogel layers minimizes the flux reduction and increases the reversibility of fouling. Compared to the pristine PEI membrane that can recover its flux to 42% after hydraulic cleaning, the PEG and poly(sulfobetaine) grafted membranes can recover their flux up to 63% and 94%, respectively. Stability tests show that the poly(sulfobetaine) hydrogel layer is stable in acid, base and chlorine solutions, whereas the PEG hydrogel layer suffers alkaline hydrolysis in base and oxidation in chlorine conditions. With its chemical stability and pronounced capability of minimizing fouling, especially irreversible fouling, protective poly(sulfobetaine) hydrogel layers have great potential for various membrane-based applications.

Morphologically intelligent underactuated robot for underwater hull cleaning

DEFF Research Database (Denmark)

Souto, Daniel; Faina, Andres; López-Peña, Fernando

2015-01-01

In this paper we discuss a new type of robot for underwater hull cleaning on ships with non-magnetic hulls. This robot is based on the concept that cleaning hulls regularly, without waiting to take them out of the water, will improve the efficiency of the ships and will permit a reduction...... in the use of the chemicals that are usually employed to prevent the growth of marine life on the hull and which are generally harmful to the environment. The robot described in this paper is an underactuated morphologically adapted robot that through an appropriate morphology and making use of the forces...... and constraints of the environment solves the most difficult problems that arise when moving along hulls. Some of these are changing planes, negotiating appendices, avoiding portholes, passing corners, and other elements. This greatly simplifies the control mechanisms that are required for its operation making...

Chemical characteristics of N2O5 observed at a rural site in Beijing winter 2016: from clean to polluted air mass

Science.gov (United States)

Wang, H.; Lu, K.; Tan, Z.; Chen, X.; Wu, Z.; Zhu, Q.; Li, X.; Liu, Y.; Shang, D.; Wu, Y.; Min, H.; Zeng, L.; Schmitt, S. H.; Rohrer, F.; Kiendler-Scharr, A.; Wahner, A.; Zhang, Y.

2017-12-01

Dinitrogen pentoxide (N2O5) plays a vital role in the atmospheric oxidation, the NOX removal and the nitrate formation. A comprehensive campaign was conducted in the wintertime of 2016 in Beijing to focus on the atmospheric oxidation, new particle formation and aerosol light extinctions during the wintertime in Beijing. The site is located at a rural area in the northeast of Beijing and about 60 km away from the city center. A newly developed instrument based on the cavity enhanced absorption spectroscopy (CEAS) was deployed to measure ambient N2O5. Simultaneous measurements of the properties of particles and the relevant trace gases are available. The daily peaks of N2O5 in the clean episodes was lower than that of polluted episodes, the campaign maximum of 1.4 ppbv were captured in the most serious pollution episode. The averaged N2O5 maximum was about 120 pptv near 20:00, which is higher than that observed in summer. The uptake coefficient of N2O5 was derived from an iterative box model approach based on the Regional Atmospheric Chemical Mechanism version 2 (RACM2), constrained to observed trace gas compounds as well as the aerosol surface concentrations. The mechanisms of the chemical compounds of aerosols (measured by AMS) affects the N2O5 uptake coefficient are explored in several chemical coordinate systems. The chemical behaviors of the ambient N2O5 concentrations for this campaign is further discussed in the context of other campaigns performed in the urban and suburban areas in Beijing.

Plasma cleaning for waste minimization

Energy Technology Data Exchange (ETDEWEB)

Ward, P.P.

1993-07-01

Although plasma cleaning is a recognized substitute for solvent cleaning in removing organic contaminants, some universal problems in plasma cleaning processes prevent wider use of plasma techniques. Lack of understanding of the fundamental mechanisms of the process, unreliable endpoint detection techniques, and slow process times make plasma cleaning processes less than desirable. Our approach to address these plasma cleaning problems is described. A comparison of plasma cleaning rates of oxygen and oxygen/sulfur hexafluoride gases shows that fluorine-containing plasmas can enhance etch rates by 400% over oxygen alone. A discussion of various endpoint indication techniques is discussed and compared for application suitability. Work toward a plasma cleaning database is discussed. In addition to the global problems of plasma cleaning, an experiment where the specific mixed-waste problem of removal of machine oils from radioactive scrap metal is discussed.

WINDOW-CLEANING

CERN Multimedia

Environmental Section / ST-TFM

2001-01-01

The two-month window-cleaning session on the Meyrin, Prévessin and LEP sites will soon begin. The cleaning contractors will work from Monday to Saturday, every week from 4.00 a.m. to 8.00 p.m. The work will be organised so as to disturb users as little as possible. In any event, a work notice will be left in each office 24 hours beforehand. To prevent any damage to documents or items which could occur despite the precautions taken, please clear completely the window-sills and the area immediately around them. If, however, for valid reasons, the work cannot be done on the scheduled day, please inform the Environmental Section by telephoning: 73753 / 74233 / 72242 If you are going to be absent during this two-month period, we should be grateful if you would clear the above mentioned areas before your departure. REMINDER To allow more thorough cleaning of the entrance doors to buildings and also facilitate the weekly work of the cleaning contractors, we ask you to make use of the notice boards at the...

ALKYLATION OF ISOBUTANE WITH 2-BUTENE WITH IONIC LIQUID AS A "CLEAN" CATALYST

Science.gov (United States)

Alkylation of isobutane with 2-butene with Ionic liquid as a "clean" catalyst Kyesang Yoo, 1 Vasudevan V. Namboodiri,2 Panagiotis G. Smirniotis,*1 and Rajender S. Varma*2 1 Department of Chemical Engineering, University of Cincinnati, Cincinnati, OH 45221-0171, USA. E...

Atmosphere self-cleaning under humidity conditions and influence of the snowflakes and artificial light interaction for water dissociation simulated by the means of COMSOL

Science.gov (United States)

Cocean, A.; Cocean, I.; Cazacu, M. M.; Bulai, G.; Iacomi, F.; Gurlui, S.

2018-06-01

The self-cleaning of the atmosphere under humidity conditions is observed due to the change in emission intensity when chemical traces are investigated with DARLIOES - the advanced LIDAR based on space- and time-resolved RAMAN and breakdown spectroscopy in conditions of consistent humidity of atmosphere. The determination was performed during the night, in the wintertime under conditions of high humidity and snowfall, in urban area of Iasi. The change in chemical composition of the atmosphere detected was assumed to different chemical reactions involving presence of the water. Water dissociation that was registered during spectral measurements is explained by a simulation of the interaction between artificial light and snowflakes - virtually designed in a spherical geometry - in a wet air environment, using COMSOL Multiphysics software. The aim of the study is to explain the decrease or elimination of some of the toxic trace chemical compounds in the process of self-cleaning in other conditions than the sun light interaction for further finding application for air cleaning under artificial conditions.

Automated cleaning of electronic components

International Nuclear Information System (INIS)

Drotning, W.; Meirans, L.; Wapman, W.; Hwang, Y.; Koenig, L.; Petterson, B.

1994-01-01

Environmental and operator safety concerns are leading to the elimination of trichloroethylene and chlorofluorocarbon solvents in cleaning processes that remove rosin flux, organic and inorganic contamination, and particulates from electronic components. Present processes depend heavily on these solvents for manual spray cleaning of small components and subassemblies. Use of alternative solvent systems can lead to longer processing times and reduced quality. Automated spray cleaning can improve the quality of the cleaning process, thus enabling the productive use of environmentally conscious materials, while minimizing personnel exposure to hazardous materials. We describe the development of a prototype robotic system for cleaning electronic components in a spray cleaning workcell. An important feature of the prototype system is the capability to generate the robot paths and motions automatically from the CAD models of the part to be cleaned, and to embed cleaning process knowledge into the automatically programmed operations

Standard Test Method for Preparing Aircraft Cleaning Compounds, Liquid Type, Water Base, for Storage Stability Testing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2002-01-01

1.1 This test method covers the determination of the stability in storage, of liquid, water-base chemical cleaning compounds, used to clean the exterior surfaces of aircraft. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Power plant chemical technology

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-01

17 contributions covering topies of fossil fuel combustion, flue gas cleaning, power plant materials, corrosion, water/steam cycle chemistry, monitoring and control were presented at the annual meeting devoted to Power Plant Chemical Technology 1996 at Kolding (Denmark) 4-6 September 1996. (EG)

Successful cleaning concept for Germany's biggest reverse osmosis plant; Ein erfolgreiches Reinigungskonzept fuer die groesste Umkehrosmoseanlage Deutschlands

Energy Technology Data Exchange (ETDEWEB)

Kempen, Hermann [Kurita Europe GmbH, Viersen (Germany); Zierau, Ronald [Zellstoff-Stendal GmbH, Arneburg (Germany)

2012-07-01

During the last years, new developments for membrane material and also for treatment chemicals have resulted in higher efficiency and reliability of reverse osmosis (RO) plants. Nevertheless, especially RO plants receiving raw water from surface waters with open intake or from waste water streams are facing problems with fouling on membranes during operation. In such cases, the efficient cleaning of membranes is mandatory to ensure long-term supply of permeate in high quality and sufficient quantity. New cleaning concepts with proprietary cleaning products are gaining in importance. The successful application of such a cleaning concept at Germany's biggest RO plant is described in this paper. (orig.)

Profile of Knowledge Management, Basic Sanitation and Attitudes towards Clean and Health Community in Kupang City

Science.gov (United States)

Nikmah; Ardi, Muhammad; Yahya, Mohamad; Upa, Muhamad D. Pua; Dirawan, Gufran Darma

2017-01-01

The objective of research is to describe the knowledge and attitude of basic sanitation management community in Kupang City. This type of research is a survey research using quantitative approach. Data were collected by using the instrument in the form of test knowledge of basic sanitation management and attitude questionnaire. The data was then…

Clean fuel technology for world energy security

Energy Technology Data Exchange (ETDEWEB)

Sunjay, Sunjay

2010-09-15

Clean fuel technology is the integral part of geoengineering and green engineering with a view to global warming mitigation. Optimal utilization of natural resources coal and integration of coal & associated fuels with hydrocarbon exploration and development activities is pertinent task before geoscientist with evergreen energy vision with a view to energy security & sustainable development. Value added technologies Coal gasification,underground coal gasification & surface coal gasification converts solid coal into a gas that can be used for power generation, chemical production, as well as the option of being converted into liquid fuels.

Optimizing UF Cleaning in UF-SWRO System Using Red Sea Water

KAUST Repository

Bahshwan, Mohanad

2012-07-01

Increasing demand for fresh water in arid and semi-arid areas, similar to the Middle East, pushed for the use of seawater desalination techniques to augment freshwater. Seawater Reverse Osmosis (SWRO) is one of the techniques that have been commonly used due to its cost effectiveness. Recently, the use of Ultrafiltration (UF) was recommended as an effective pretreatment for SWRO membranes, as opposed to conventional methods (i.e. sand filtration). During UF operation, intermittent cleaning is required to remove particles and contaminants from the membrane\\'s surface and pores. The different cleaning steps consume chemicals and portion of the product water, resulting in a decrease in the overall effectiveness of the process and hence an increase in the production cost. This research focused on increasing the plant\\'s efficiency through optimizing the cleaning protocol without jeopardizing the effectiveness of the cleaning process. For that purpose, the design of experiment (DOE) focused on testing different combinations of these cleaning steps while all other parameters (such as filtration flux or backwash flux) remained constant. The only chemical used was NaOCI during the end of each experiment to restore the trans-membrane pressure (TMP) to its original state. Two trains of Dow™ Ultrafiltration SFP-2880 were run in parallel for this study. The first train (named UF1) was kept at the manufacturer\\'s recommended cleaning steps and frequencies, while the second train (named UF2) was varied according to the DOE. The normalized final TMP was compared to the normalized initial TMP to measure the fouling rate of the membrane at the end of each experiment. The research was supported by laboratory analysis to investigate the cause of the error in the data by analyzing water samples collected at different locations. Visual inspection on the results from the control unit showed that the data cannot be reproduced with the current feed water quality. Statistical analysis

Cleaning at Home and at Work in Relation to Lung Function Decline and Airway Obstruction.

Science.gov (United States)

Svanes, Øistein; Bertelsen, Randi J; Lygre, Stein H L; Carsin, Anne E; Antó, Josep M; Forsberg, Bertil; García-García, José M; Gullón, José A; Heinrich, Joachim; Holm, Mathias; Kogevinas, Manolis; Urrutia, Isabel; Leynaert, Bénédicte; Moratalla, Jesús M; Le Moual, Nicole; Lytras, Theodore; Norbäck, Dan; Nowak, Dennis; Olivieri, Mario; Pin, Isabelle; Probst-Hensch, Nicole; Schlünssen, Vivi; Sigsgaard, Torben; Skorge, Trude D; Villani, Simona; Jarvis, Debbie; Zock, Jan P; Svanes, Cecilie

2018-05-01

Cleaning tasks may imply exposure to chemical agents with potential harmful effects to the respiratory system, and increased risk of asthma and respiratory symptoms among professional cleaners and in persons cleaning at home has been reported. Long-term consequences of cleaning agents on respiratory health are, however, not well described. This study aimed to investigate long-term effects of occupational cleaning and cleaning at home on lung function decline and airway obstruction. The European Community Respiratory Health Survey (ECRHS) investigated a multicenter population-based cohort at three time points over 20 years. A total of 6,235 participants with at least one lung function measurement from 22 study centers, who in ECRHS II responded to questionnaire modules concerning cleaning activities between ECRHS I and ECRHS II, were included. The data were analyzed with mixed linear models adjusting for potential confounders. As compared with women not engaged in cleaning (ΔFEV 1  = -18.5 ml/yr), FEV 1 declined more rapidly in women responsible for cleaning at home (-22.1; P = 0.01) and occupational cleaners (-22.4; P = 0.03). The same was found for decline in FVC (ΔFVC = -8.8 ml/yr; -13.1, P = 0.02; and -15.9, P = 0.002; respectively). Both cleaning sprays and other cleaning agents were associated with accelerated FEV 1 decline (-22.0, P = 0.04; and -22.9, P = 0.004; respectively). Cleaning was not significantly associated with lung function decline in men or with FEV 1 /FVC decline or airway obstruction. Women cleaning at home or working as occupational cleaners had accelerated decline in lung function, suggesting that exposures related to cleaning activities may constitute a risk to long-term respiratory health.

Decontamination issues for chemical and biological warfare agents: how clean is clean enough?

Science.gov (United States)

Raber, E; Jin, A; Noonan, K; McGuire, R; Kirvel, R D

2001-06-01

The objective of this assessment is to determine what level of cleanup will be required to meet regulatory and stakeholder needs in the case of a chemical and/or biological incident at a civilian facility. A literature review for selected, potential chemical and biological warfare agents shows that dose information is often lacking or controversial. Environmental regulatory limits or other industrial health guidelines that could be used to help establish cleanup concentration levels for such agents are generally unavailable or not applicable for a public setting. Although dose information, cleanup criteria, and decontamination protocols all present challenges to effective planning, several decontamination approaches are available. Such approaches should be combined with risk-informed decision making to establish reasonable cleanup goals for protecting health, property, and resources. Key issues during a risk assessment are to determine exactly what constitutes a safety hazard and whether decontamination is necessary or not for a particular scenario. An important conclusion is that cleanup criteria are site dependent and stakeholder specific. The results of a modeling exercise for two outdoor scenarios are presented to reinforce this conclusion. Public perception of risk to health, public acceptance of recommendations based on scientific criteria, political support, time constraints, and economic concerns must all be addressed in the context of a specific scenario to yield effective and acceptable decontamination.

Interstellar matrices: the chemical composition and evolution of interstellar ices as observed by ISO.

Science.gov (United States)

d'Hendecourt, L; Dartois, E

2001-03-15

Matrix isolation techniques have been developed in the early sixties as a tool for studying the spectroscopic properties of out of equilibrium species (atoms, radicals, ions, reactive molecules), embedded in rare gas inert matrices at low temperatures. Cold interstellar grains surfaces are able to condense out gas phase molecules, routinely observed by radioastronomy. These grain 'mantles' can be considered as 'interstellar matrices'. However, these matrices are not clean and unreactive. They are made principally of dirty ices whose composition must be determined carefully to assess the importance of the solid state chemistry that takes place in the Interstellar Medium. Infrared spectroscopy, both in astronomy and in the laboratory, is the unique tool to determine the chemical composition of these ices. Astronomical spectra can directly be compared with laboratory ones obtained using classical matrix isolation techniques. Furthermore, dedicated experiments may be undertaken to further improve the understanding of the basic physico-chemical processes that take place in cosmic ices.

Electro-membrane processes for flue gas cleaning

Energy Technology Data Exchange (ETDEWEB)

Larsen, T. F.

1997-12-31

Various techniques for NO removal in Membrane Contactor were considered. However the NO absorption in a liquid adsorbent with chemical enhancement and its ease for regeneration, was selected as the most practicable choice. Various different compounds for chemical enhancement were studied and Fe(II)-chelate enhanced adsorbent was selected for further studies. The technical feasibility of Fe(II)-chelate enhanced adsorbent for obtaining greater than 80% NO removal have been successfully established. Even though the membrane area required for greater than 80% NO removal has been found to be about 500 m{sup 2}/MW{sub c} (compared to 50 - 150 m{sup 2}/MW{sub c}, for 95% SO{sub 2} removal, depending on the membrane characteristics), suitable Membrane Contactor design has been proposed for carrying out the process at an acceptable gas side pressure drop. The electro-membrane processes for the regeneration of adsorbents have been studied both theoretically and experimentally. The theoretical studies have concerned the study of basic functions of both the bipolar membranes and charge laden (anion/cation) membranes. Suitable experimental techniques have been devised for studying of these basic parameters (e.g. charge transport number, salt diffusion through membranes, current-voltage characteristics of bipolar membranes and electrical resistance of charge laden membranes). These parameters have further been utilized in the mechanistic model of combined membranes in an ED cell (electrodialysis). Based on these fundamental studies and analysis of process requirements, suitable configuration of ED cell has been developed and verified by experimental studies. The effect of both the stack design parameters (e.g. number of cells, membrane type and spacer design) and the operational parameters (e.g. temperature, electrolyte concentration, liquid velocity and current density) have been studied for optimization of energy consumption for regeneration of loaded adsorbents. As a result

Reactor water clean-up device

International Nuclear Information System (INIS)

Tanaka, Koji; Egashira, Yasuo; Shimada, Fumie; Igarashi, Noboru.

1983-01-01

Purpose: To save a low temperature reactor water clean-up system indispensable so far and significantly simplify the system by carrying out the reactor water clean-up solely in a high temperature reactor water clean-up system. Constitution: The reactor water clean-up device comprises a high temperature clean-up pump and a high temperature adsorption device for inorganic adsorbents. The high temperature adsorption device is filled with amphoteric ion adsorbing inorganic adsorbents, or amphoteric ion adsorbing inorganic adsorbents and anionic adsorbing inorganic adsorbents. The reactor water clean-up device introduces reactor water by the high temperature clean-up pump through a recycling system to the high temperature adsorption device for inorganic adsorbents. Since cations such as cobalt ions and anions such as chlorine ions in the reactor water are simultaneously removed in the device, a low temperature reactor water clean-up system which has been indispensable so far can be saved to realize the significant simplification for the entire system. (Seki, T.)

Basic mechanisms of photosynthesis and applications to improved production and conversion of biomass to fuels and chemical products

Energy Technology Data Exchange (ETDEWEB)

El-Sayed, M. [Georgia Institute of Tech., Atlanta, GA (United States); Greenbaum, E. [Oak Ridge National Laboratory, TN (United States); Wasielewski, M. [Argonne National Lab., IL (United States)

1996-09-01

Natural photosynthesis, the result of 3.5 billion years of evolutionary experimentation, is the best proven, functional solar energy conversion technology. It is responsible for filling the vast majority of humanity`s energy, nutritional, and materials needs. Understanding the basic physical chemical principles underlying photosynthesis as a working model system is vital to further exploitation of this natural technology. These principles can be used to improve or modify natural photosynthesis so that it is more efficient or so that it can produce unusual products such as hydrogen, methane, methanol, ethanol, diesel fuel substitutes, biodegradable materials, or other high value chemical products. Principles garnered from the natural process can also be used to design artificial photosynthetic devices that employ analogs of natural antenna and reaction center function, self-assembly and repair concepts, photoinduced charge transfer processes, photoprotection, and dark reactions that facilitate catalytic action to convert light into, useful chemical or electrical energy. The present broad understanding of many structural and functional aspects of photosynthesis has resulted from rapid recent research progress. X-ray structures of several key photosynthetic reaction centers and antenna systems are available, and the overall principles controlling photoinduced energy and electron transfer are being established.

Microbial water quality in clean water tanks following inspection and cleaning

DEFF Research Database (Denmark)

Christensen, Sarah Christine Boesgaard; Esbjørn, Anne; Mollerup, Finn

Increased bacterial counts are often registered in drinking water leaving clean water tanks after the tanks have been emptied, inspected and cleaned by flushing. To investigate the reason for the increased bacterial concentrations and consequently limit it, samples from two clean water tanks befo...... start-up of the tanks, which may indicate that a substantial part of the bacteria in the drinking water leaving the tanks originated from the sand filter. This was supported by 16S DNA analyses....

Measurement of the Residual Sodium and Reaction Compounds on a Cleaned Cold Trap

International Nuclear Information System (INIS)

Kim, Byung Ho; Jeong, Ji Young; Kim, Jong Man; Choi, Byung Hae; Nam, Ho Yun Nam

2006-01-01

The purpose of a cleaning process is to remove the residual sodium adhering to the component walls once it has been properly drained. It is necessary to clean and decontaminate a component, especially the large components of the primary coolant system; such as the intermediate heat exchangers and the primary pump. Improper and inadequate cleaning has in a number of cases resulted in problems in the storage, handling, and reuse of components. Inadequate and incomplete removal of sodium results in residues which may contain metallic sodium and alkaline compounds such as sodium hydroxide, sodium oxide, sodium carbonate, and various types of alcoholates. Reinsertion of components containing these compounds into a high-temperature sodium system can result in either a intergranular penetration characteristic of a high-oxygen sodium or an accelerated corrosion due to oxygen. Cleaning methods are needed that will avoid a deleterious local overheating, material surface degradation or deposits, a chemical, physical, or mechanical damage, and external effects. It is important to determine the levels of residual sodium that can be accepted so that those deleterious effects will not negate the reuse of the component. The purpose of this paper is to measure the amount of the sodium and the reaction compounds remaining on a component after a cleaning and prepare acceptable criteria for the reuse of components which have been subjected to a sodium cleaning

Accurate Quantitation of Water-amide Proton Exchange Rates Using the Phase-Modulated CLEAN Chemical EXchange (CLEANEX-PM) Approach with a Fast-HSQC (FHSQC) Detection Scheme

International Nuclear Information System (INIS)

Hwang, Tsang-Lin; Zijl, Peter C.M. van; Mori, Susumu

1998-01-01

Measurement of exchange rates between water and NH protons by magnetization transfer methods is often complicated by artifacts, such as intramolecular NOEs, and/or TOCSY transfer from Cα protons coincident with the water frequency, or exchange-relayed NOEs from fast exchanging hydroxyl or amine protons. By applying the Phase-Modulated CLEAN chemical EXchange (CLEANEX-PM) spin-locking sequence, 135 o (x) 120 o (-x) 110 o (x) 110 o (-x) 120 o (x) 135 o (-x) during the mixing period, these artifacts can be eliminated, revealing an unambiguous water-NH exchange spectrum. In this paper, the CLEANEX-PM mixing scheme is combined with Fast-HSQC (FHSQC) detection and used to obtain accurate chemical exchange rates from the initial slope analysis for a sample of 15N labeled staphylococcal nuclease. The results are compared to rates obtained using Water EXchange filter (WEX) II-FHSQC, and spin-echo-filtered WEX II-FHSQC measurements, and clearly identify the spurious NOE contributions in the exchange system

A Miniature Wastewater Cleaning Plant to Demonstrate Primary Treatment in the Classroom

Science.gov (United States)

Ne´el, Bastien; Cardoso, Catia; Perret, Didier; Bakker, Eric

2015-01-01

A small-scale wastewater cleaning plant is described that includes the key physical pretreatment steps followed by the chemical treatment of mud by flocculation. Water, clay particles, and riverside deposits mimicked odorless wastewater. After a demonstration of the optimization step, the flocculation process was carried out with iron(III)…

LC clean-up and GC/MS analysis of polycyclic aromatic hydrocarbons in river sediment

International Nuclear Information System (INIS)

Nondek, L.; Kuzilek, M.; Krupicka, S.

1993-01-01

An LC clean-up procedure based upon a complexation between polycyclic aromatic hydrocarbons (PAHs) and silica with chemically bonded 2,4-dinitroaniline has been combined with GC/MS. The LC pre-separation makes it possible to obtain a relatively clean fraction of PAHs free from alkanes, alkylbenzenes and naphthalenes, PCBs, chlorinated pesticides and many other interfering compounds. This fraction has been analyzed using capillary GC and mass selective detector (MSD). Substantial improvement of the MS spectra of PAHs with three or more fused benzene rings is achieved. (orig.)

Comparison of glow discharge cleaning with Taylor-type discharge cleaning on JFT-2

International Nuclear Information System (INIS)

Yokokura, Kenji; Matsuzaki, Yoshimi; Tani, Takashi

1983-01-01

Method of glow discharge cleaning (GDC) was applied to JFT-2 tokamak and the cleaning effect of GDC was compared with that of taylor-type discharge cleaning (TDC) on the same machin. Results show clearly their individual characteristics to remove light impurities. Their abilities of surface cleaning were compared each other by observing cleanliness of sample surfaces with a AES and by measuring decay times of produced gas pressures during discharge cleanings with a mass-analyser. It was shown that TDC method is better by several times than GDC method from a mass-analyser measurement. Moreover discharge cleaning time necessary to reduce light impurities in the normal plasma to a certain level was compared by monitoring time evolution of radiation loss power with a bolometer, and the time by TDC was only one fifth of that by GDC. The advantage of TDC may come from the excellently high hydrogen flux which interacts with the limiter and the wall. (author)

Biomonitoring in a clean and a multi-contaminated estuary based on biomarkers and chemical analyses in the endobenthic worm Nereis diversicolor

Energy Technology Data Exchange (ETDEWEB)

Durou, Cyril [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France) and Institut de Biologie et Ecologie Appliquees, CEREA, Universite Catholique de l' Ouest, 44 rue Rabelais, 49008 Angers Cedex 01 (France)]. E-mail: cyril.durou@uco.fr; Poirier, Laurence [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France); Amiard, Jean-Claude [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France); Budzinski, Helene [CNRS UMR 5472, LPTC, Universite de Bordeaux I, 33405 Talence (France); Gnassia-Barelli, Mauricette [UMR INRA UNSA 1112 ROSE, Faculte des Sciences, BP 71, 06108 Nice Cedex 2 (France); Lemenach, Karyn [CNRS UMR 5472, LPTC, Universite de Bordeaux I, 33405 Talence (France); Peluhet, Laurent [CNRS UMR 5472, LPTC, Universite de Bordeaux I, 33405 Talence (France); Mouneyrac, Catherine [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France); Institut de Biologie et Ecologie Appliquees, CEREA, Universite Catholique de l' Ouest, 44 rue Rabelais, 49008 Angers Cedex 01 (France); Romeo, Michele [UMR INRA UNSA 1112 ROSE, Faculte des Sciences, BP 71, 06108 Nice Cedex 2 (France); Amiard-Triquet, Claude [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France)

2007-07-15

Relationships between biochemical and physiological biomarkers (acetylcholinesterase [AChE], catalase, and glutathione S-transferase [GST] activities, thiobarbituric acid reactive substances, glycogen, lipids and proteins) and accumulated concentrations of contaminants (polychlorinated biphenyls [PCBs], polycyclic aromatic hydrocarbons and metals) were examined in the keystone species Nereis diversicolor. The chemical analyses of worms and sediments allowed the designation of the Seine estuary and the Authie estuary as a polluted and relatively clean site respectively. Worms from the Seine estuary exhibited higher GST and lower AChE activities. Generally, larger worms had higher concentrations of energy reserves. Principal component analyses clearly highlighted intersite differences: in the first plan, GST activities and chemical concentrations were inversely related to concentrations of energy reserves; in the second one, PCB concentrations and AChE activity were inversely related. Depleted levels of energy reserves could be a consequence of combating toxicants and might predict effects at higher levels of biological organization. The use of GST and AChE activities and energy reserve concentrations as biomarkers is validated in the field in this keystone species. - The use of N. diversicolor as a biomonitor of environmental quality via the measurement of biomarkers and accumulated concentrations of contaminants is validated in the field.

Silvering substrates after CO2 snow cleaning

Science.gov (United States)

Zito, Richard R.

2005-09-01

There have been some questions in the astronomical community concerning the quality of silver coatings deposited on substrates that have been cleaned with carbon dioxide snow. These questions center around the possible existence of carbonate ions left behind on the substrate by CO2. Such carbonate ions could react with deposited silver to produce insoluble silver carbonate, thereby reducing film adhesion and reflectivity. Carbonate ions could be produced from CO2 via the following mechanism. First, during CO2 snow cleaning, a small amount of moisture can condense on a surface. This is especially true if the jet of CO2 is allowed to dwell on one spot. CO2 gas can dissolve in this moisture, producing carbonic acid, which can undergo two acid dissociations to form carbonate ions. In reality, it is highly unlikely that charged carbonate ions will remain stable on a substrate for very long. As condensed water evaporates, Le Chatelier's principle will shift the equilibrium of the chain of reactions that produced carbonate back to CO2 gas. Furthermore, the hydration of CO2 reaction of CO2 with H20) is an extremely slow process, and the total dehydrogenation of carbonic acid is not favored. Living tissues that must carry out the equilibration of carbonic acid and CO2 use the enzyme carbonic anhydrase to speed up the reaction by a factor of one million. But no such enzymatic action is present on a clean mirror substrate. In short, the worst case analysis presented below shows that the ratio of silver atoms to carbonate radicals must be at least 500 million to one. The results of chemical tests presented here support this view. Furthermore, film lift-off tests, also presented in this report, show that silver film adhesion to fused silica substrates is actually enhanced by CO2 snow cleaning.

Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se2 thin-film solar cell absorbers

Science.gov (United States)

Lehmann, Jascha; Lehmann, Sebastian; Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch.; Bär, Marcus; Sadewasser, Sascha

2014-12-01

Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for "realistic" surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In1-xGax)Se2 thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH3-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is - apart from a slight change in surface composition - identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

Limonene and tetrahydrofurfuryl alcohol cleaning agent

Science.gov (United States)

Bohnert, George W.; Carter, Richard D.; Hand, Thomas E.; Powers, Michael T.

1996-05-07

The present invention is a tetrahydrofurfuryl alcohol and limonene or terpineol cleaning agent and method for formulating and/or using the cleaning agent. This cleaning agent effectively removes both polar and nonpolar contaminants from various electrical and mechanical parts and is readily used without surfactants, thereby reducing the need for additional cleaning operations. The cleaning agent is warm water rinsable without the use of surfactants. The cleaning agent can be azeotropic, enhancing ease of use in cleaning operations and ease of recycling.

Limonene and tetrahydrofurfurly alcohol cleaning agent

Science.gov (United States)

Bohnert, George W.; Carter, Richard D.; Hand, Thomas E.; Powers, Michael T.

1997-10-21

The present invention is a tetrahydrofurfuryl alcohol and limonene cleaning agent and method for formulating and/or using the cleaning agent. This cleaning agent effectively removes both polar and nonpolar contaminants from various electrical and mechanical parts and is readily used without surfactants, thereby reducing the need for additional cleaning operations. The cleaning agent is warm water rinsable without the use of surfactants. The cleaning agent can be azeotropic, enhancing ease of use in cleaning operations and ease of recycling.

Clean Hands Count

Medline Plus

Full Text Available ... has been rented. This feature is not available right now. Please try again later. Published on May ... 34 How The Clean Hands - Safe Hands System Works - Duration: 3:38. Clean Hands-Safe Hands 5, ...

Cleaning protocol for a FO membrane fouled in wastewater reuse

KAUST Repository

Valladares Linares, Rodrigo; Li, Zhenyu; Yangali-Quintanilla, Victor; Li, Qingyu; Amy, Gary L.

2013-01-01

Forward osmosis (FO) is an emerging technology which can be applied in water reuse applications. Osmosis is a natural process that involves less energy consumption than reverse osmosis (RO), and therefore can be applied as a dilution process before low-pressure RO; it is expected to compete favourably against current advanced water reuse technologies that use microfiltration/ultrafiltration and RO. The focus of this research was to assess the efficiency of different cleaning procedures to remove fouling from the surface of a FO membrane during the operation of a submerged system working in FO-mode (active layer (AL) facing feed solution) intended for secondary wastewater effluent (SWWE) recovery, using seawater as draw solution (DS), which will be diluted and can further be fed to a low-pressure RO unit to produce fresh water. Natural organic matter (NOM) fouling was expected to affect the AL, while for the support layer (SL), transparent exopolymer particles (TEP) were used as indicators of fouling due to their stickiness and propensity to enhance the attachment of other foulants in seawater on the membrane surface. The composition of the NOM fouling layer was determined after proper characterisation with a liquid chromatograph coupled with organic carbon detection (LC-OCD), showing biopolymers and protein-like substances as the main constituents. NOM fouling showed high hydraulic reversibility after a 25% flux decline was observed, up to 89.5% when in situ air scouring for 15 min was used as a cleaning technique. Chemical cleaning with a mixture of Alconox, an industrial detergent containing phosphates, and sodium EDTA showed to increase the reversibility (93.6%). Osmotic backwash using a 4% NaCl solution and DI water proved to be ineffective to recover flux due to the salt diffusion phenomena occurring at the AL. Part of the flux that could not be recovered is attributable to TEP fouling on the SL, which forms clusters clearly identifiable with an optical

Cleaning protocol for a FO membrane fouled in wastewater reuse

KAUST Repository

Valladares Linares, Rodrigo

2013-05-30

Forward osmosis (FO) is an emerging technology which can be applied in water reuse applications. Osmosis is a natural process that involves less energy consumption than reverse osmosis (RO), and therefore can be applied as a dilution process before low-pressure RO; it is expected to compete favourably against current advanced water reuse technologies that use microfiltration/ultrafiltration and RO. The focus of this research was to assess the efficiency of different cleaning procedures to remove fouling from the surface of a FO membrane during the operation of a submerged system working in FO-mode (active layer (AL) facing feed solution) intended for secondary wastewater effluent (SWWE) recovery, using seawater as draw solution (DS), which will be diluted and can further be fed to a low-pressure RO unit to produce fresh water. Natural organic matter (NOM) fouling was expected to affect the AL, while for the support layer (SL), transparent exopolymer particles (TEP) were used as indicators of fouling due to their stickiness and propensity to enhance the attachment of other foulants in seawater on the membrane surface. The composition of the NOM fouling layer was determined after proper characterisation with a liquid chromatograph coupled with organic carbon detection (LC-OCD), showing biopolymers and protein-like substances as the main constituents. NOM fouling showed high hydraulic reversibility after a 25% flux decline was observed, up to 89.5% when in situ air scouring for 15 min was used as a cleaning technique. Chemical cleaning with a mixture of Alconox, an industrial detergent containing phosphates, and sodium EDTA showed to increase the reversibility (93.6%). Osmotic backwash using a 4% NaCl solution and DI water proved to be ineffective to recover flux due to the salt diffusion phenomena occurring at the AL. Part of the flux that could not be recovered is attributable to TEP fouling on the SL, which forms clusters clearly identifiable with an optical

Investigation of Alternative Approaches for Cleaning Mott Porous Metal Filters

International Nuclear Information System (INIS)

Poirier, M.R.

2003-01-01

The Department of Energy selected Caustic Side Solvent Extraction (CSSX) as the preferred cesium removal technology for Savannah River Site (SRS) waste. As a pretreatment step for the CSSX flowsheet, the incoming salt solution that contains entrained sludge is contacted with monosodium titanate (MST) to adsorb strontium and select actinides. The resulting slurry is filtered to remove the sludge and MST. Filter fouling occurs during this process. At times, personnel can increase the filtrate rate by backpulsing or scouring. At other times, the filtrate rate drops significantly and only chemical cleaning will restore filter performance. The current baseline technology for filter cleaning uses 0.5 M oxalic acid. The Salt Processing Project (SPP) at SRS, through the Tanks Focus Area, requested an evaluation of other cleaning agents to determine their effectiveness at removing trapped sludge and MST solids compared with the baseline oxalic acid method. A review of the technical literature identified compounds that appear effective at dissolving solid compounds. Consultation with the SPP management team, engineering personnel, and researchers led to a selection of oxalic acid, nitric acid, citric acid, and ascorbic acid for testing. Tests used simulated waste and actual waste as follows. Personnel placed simulated or actual SRS High Level Waste sludge and MST in a beaker. They added the selected cleaning agents, stirred the beakers, and collected supernate samples periodically analyzing for dissolved metals

Indoor secondary pollutants from cleaning product and air freshener use in the presence of ozone

DEFF Research Database (Denmark)

Singer, B.C.; Coleman, B.K.; Destaillats, H.

2006-01-01

introduction. In the absence of reactive chemicals, the chamber ozone level was approximately 60 ppb. Ozone was substantially consumed following cleaning product use, mainly by homogeneous reaction. For the AFR, ozone consumption was weaker and heterogeneous reaction with sorbed AFR-constituent VOCs...... than 100 mu g m(-3)) in some experiments. Ozone consumption and elevated hydroxyl radical concentrations persisted for 10-12 h following brief cleaning events, indicating that secondary pollutant production can persist for extended periods. (c) 2006 Elsevier Ltd. All rights reserved....

Basic Research Needs for Clean and Efficient Combustion of 21st Century Transportation Fuels

Energy Technology Data Exchange (ETDEWEB)

McIlroy, A.; McRae, G.; Sick, V.; Siebers, D. L.; Westbrook, C. K.; Smith, P. J.; Taatjes, C.; Trouve, A.; Wagner, A. F.; Rohlfing, E.; Manley, D.; Tully, F.; Hilderbrandt, R.; Green, W.; Marceau, D.; O' Neal, J.; Lyday, M.; Cebulski, F.; Garcia, T. R.; Strong, D.

2006-11-01

To identify basic research needs and opportunities underlying utilization of evolving transportation fuels, with a focus on new or emerging science challenges that have the potential for significant long-term impact on fuel efficiency and emissions.

Clean coal technologies: A business report

International Nuclear Information System (INIS)

Anon.

1993-01-01

The book contains four sections as follows: (1) Industry trends: US energy supply and demand; The clean coal industry; Opportunities in clean coal technologies; International market for clean coal technologies; and Clean Coal Technology Program, US Energy Department; (2) Environmental policy: Clean Air Act; Midwestern states' coal policy; European Community policy; and R ampersand D in the United Kingdom; (3) Clean coal technologies: Pre-combustion technologies; Combustion technologies; and Post-combustion technologies; (4) Clean coal companies. Separate abstracts have been prepared for several sections or subsections for inclusion on the data base

Financing clean energy market creation. Clean energy ventures, venture capitalists and other investors

Energy Technology Data Exchange (ETDEWEB)

Teppo, T. [Helsinki Univ. of Technology, Espoo (Finland). Development and Management in Industry

2006-07-01

Many factors have emerged for change towards cleaner and more efficient technologies and services: climate change, increasing oil demands, and rising living standards in many parts of the world are putting an ever-increasing strain on the environment. Recently, these drivers have fueled the formation of a clean energy venture capital market where both independent venture capitalists (VCs) and corporate venture capitalists (CVCs) have invested in clean energy start-ups. Financing of clean energy market creation is the focus of this dissertation. The dissertation contributes to several bodies of literature in the area of entrepreneurship, new industry creation, corporate venturing, and venture capital research. The dissertation uses a grounded theory approach. The study is guided by three data collection approaches with an emphasis on the first two. First, interviews with European and North American VC and CVC firms that have invested in the clean energy sector were carried out. Second, a clean energy venture financing survey that consisted of qualitative, essay-format questions and some quantitative questions was carried out. Third, interviews with clean energy stakeholders were carried out in order to gain a better understanding of the emerging sector. The research results consist of three main findings. First, the research results suggest that clean energy ventures face the following three main entrepreneurial challenges: financing, market education, and growth management. A further study of three clean energy industry categories revealed additional challenges that varied according to the industry development stage. Second, the results demonstrate that, from a venture capitalist perspective, clean energy venture risk characteristics can be divided into two groups: generally recognized risk characteristics and cognitive risk characteristics. The identified generally recognized risk characteristics were market demand and adaptation, incompatibility with the VC model

Preparation of atomically clean and flat Si(1 0 0) surfaces by low-energy ion sputtering and low-temperature annealing

International Nuclear Information System (INIS)

Kim, J.C.; Ji, J.-Y.; Kline, J.S.; Tucker, J.R.; Shen, T.-C.

2003-01-01

Si(1 0 0) surfaces were prepared by wet-chemical etching followed by 0.3-1.5 keV Ar ion sputtering, either at elevated or room temperature (RT). After a brief anneal under ultrahigh vacuum (UHV) conditions, the resulting surfaces were examined by scanning tunneling microscopy. We find that wet-chemical etching alone cannot produce a clean and flat Si(1 0 0) surface. However, subsequent 300 eV Ar ion sputtering at room temperature followed by a 700 deg. C anneal yields atomically clean and flat Si(1 0 0) surfaces suitable for nanoscale device fabrication

IONIC LIQUIDS AS A CLEAN CATALYST FOR THE ALKYLATION OF ISOBUTANE WITH 2-BUTENE

Science.gov (United States)

Ionic liquids as a clean catalyst for the alkylation of isobutane with 2-buteneKyesang Yoo, a Vasudevan V. Namboodiri,b Panagiotis G. Smirniotis,*a and Rajender S. Varma*b a Department of Chemical Engineering, University of Cincinnati, Cincinnati, OH 45221-0171, USA. ...

Clean coal technology

International Nuclear Information System (INIS)

Abelson, P.H.

1990-01-01

One of the major technology challenges in the next decade will be to develop means of using coal imaginatively as a source of chemicals and in a more energy-efficient manner. The Clean Air Act will help to diminish the acid rain but will not reduce CO 2 emissions. The Department of Energy (DOE) is fostering many innovations that are likely to have a positive effect on coal usage. Of the different innovations in the use of coal fostered by DOE, two are of particular interest. One is the new pressurized fluid bed combustion (PFBC) combined-cycle demonstration. The PFBC plant now becoming operational can reduce SO 2 emissions by more than 90% and NO x emissions by 50-70%. A second new technology co-sponsored by DOE is the Encoal mild coal gasification project that will convert a sub-bituminous low-BTU coal into a useful higher BTU solid while producing significant amounts of a liquid fuel

Design of off-gas and air cleaning systems at nuclear power plants

International Nuclear Information System (INIS)

1987-01-01

The primary purpose of this report is to describe the current design of air and process off-gas cleaning technologies used in nuclear power plants (NPPs). Because of the large inventory of fission products that are produced in the fuel (i.e. in the range of 5x10 19 Bq per GW(e)·a) and the highly restrictive airborne radionuclide release limits being established by Member States, air and process off-gas cleaning technologies are constantly being improved to provide higher airborne radionuclide recovery efficiencies and a smaller probability of malfunction. For various technologies considered an attempt has been made to provide the following information: (a) Process description in terms of principles of off-gas and air cleaning, operating parameters and system performance; (b) Design for normal and accident situations; (c) Design of components with regard to construction materials, size, shape and geometry of the system, resistance to chemical and physical degradation from the operational environment, safety and quality assurance requirements

Air toxics and the 1990 Clean Air Act: Managing trace element emissions

International Nuclear Information System (INIS)

Chow, W.; Levin, L.; Miller, M.J.

1992-01-01

The US Environmental Protection Agency (EPA) has historically regulated air toxics (hazardous air pollutants) under Section 112 of the Clean Air Act. To date, EPA has established emission standards for 8 hazardous air pollutants (arsenic, asbestos, benzene, beryllium, mercury, radionuclides, coke oven emissions and vinyl chloride). The US electric utility industry was not determined to be a source category requiring regulation for any of the eight chemicals. Of the eight, radionuclides were the last species for which EPA established hazardous emissions standards. In this instance, EPA determined that the risks associated with electric utility fossil fuel power plant emissions were sufficiently low that they should not be regulated. However, the 1990 Clean Air Act Amendments require a new evaluation of the electric utility industry emissions of hazardous air pollutants. This paper summarizes the key features of the air toxics provisions of the Clean Air Act Amendments, describes EPRI's activities on the subject, and provides some preliminary insights from EPRI's research to date

NOM and TEP fouling of a forward osmosis (FO) membrane: Foulant identification and cleaning

KAUST Repository

Valladares Linares, Rodrigo

2012-12-01

The study of forward osmosis (FO) membranes has increased due to the already demonstrated advantages compared to high-energy membrane processes such as reverse osmosis (RO). This research focuses on characterization of the natural organic matter (NOM) fraction causing fouling on the active layer (AL) of a FO membrane in a novel plate and frame module configuration, facing secondary wastewater effluent as a feed solution (FS) and seawater used as a draw solution (DS). In addition, transparent exopolymer particles (TEP) were observed on the support layer (SL) of the membrane in contact with the DS. The NOM fouling layer, after characterizing the water samples and membranes used, was found to be composed of biopolymers and protein-like substances, which adversely affect the flux of water through the FO membrane. However, NOM fouling showed high reversibility, up to 90% when air scouring for 15. min is used as a cleaning technique. The irreversible fouling in this work was found to be 8.2% after chemical cleaning. On the support layer of the membrane, TEP formed clusters clearly identifiable with an optical microscope and a TEP-specific dye. Chemical cleaning with 1% NaOCl for 10. min proved to be the most effective method to remove TEP. © 2012.

NOM and TEP fouling of a forward osmosis (FO) membrane: Foulant identification and cleaning

KAUST Repository

Valladares Linares, Rodrigo; Yangali-Quintanilla, Victor; Li, Zhenyu; Amy, Gary L.

2012-01-01

The study of forward osmosis (FO) membranes has increased due to the already demonstrated advantages compared to high-energy membrane processes such as reverse osmosis (RO). This research focuses on characterization of the natural organic matter (NOM) fraction causing fouling on the active layer (AL) of a FO membrane in a novel plate and frame module configuration, facing secondary wastewater effluent as a feed solution (FS) and seawater used as a draw solution (DS). In addition, transparent exopolymer particles (TEP) were observed on the support layer (SL) of the membrane in contact with the DS. The NOM fouling layer, after characterizing the water samples and membranes used, was found to be composed of biopolymers and protein-like substances, which adversely affect the flux of water through the FO membrane. However, NOM fouling showed high reversibility, up to 90% when air scouring for 15. min is used as a cleaning technique. The irreversible fouling in this work was found to be 8.2% after chemical cleaning. On the support layer of the membrane, TEP formed clusters clearly identifiable with an optical microscope and a TEP-specific dye. Chemical cleaning with 1% NaOCl for 10. min proved to be the most effective method to remove TEP. © 2012.

Comparative researches concerning cleaning chosen construction materials surface layer using UV and IR laser radiation

International Nuclear Information System (INIS)

Napadlek, W.; Marczak, J.; Kubicki, J.; Szudrowicz, M.

2002-01-01

The paper presents comparative research studies of cleaning out of deposits and pollution disposals on different constructional materials like; steel, cast iron, aluminium, copper by using UV and IR laser radiation of wavelength λ =1.064 μm; λ = 0.532 μm; λ = 0.355 μm and λ = 0.266 μm and also impulse laser TEA CO 2 at radiation λ = 10.6 μm were used for the experiments. Achieved experimental results gave us basic information on parameters and conditions and application of each used radiation wavelength. Each kind of pollution and base material should be individually treated, selecting the length of wave and radiation energy density. Laser microtreatment allows for broad cleaning application of the surface of constructional materials as well as may be used in future during manufacturing processes as: preparation of surface for PVD technology, galvanotechnics, cleaning of the surface of machine parts etc. (author)

Wind energy basics a guide to home- and community-scale wind energy systems

CERN Document Server

Gipe, Paul

2009-01-01

The availability of clean, renewable power is without question going to be the defining challenge and goal of the 21st century, and wind will lead the way. Internationally acclaimed wind energy expert Paul Gipe is as soberly critical of past energy mistakes as he is convincingly optimistic about the future. The overwhelming challenge of transforming our world from one of fossil carbon to one of clean power seems daunting at best-and paralyzingly impractical at worst. "Wind Energy Basics" offers a solution. Wind power can realistically not only replace the lion's share of oil-, coal-, and natural gasndash; fired electrical plants in the U.S., but also can add enough extra power capacity to allow for most of the cars in the nation to run on electricity. Gipe explains why such a startlingly straightforward solution is eminently doable and can be accomplished much sooner than previously thought-and will have the capacity to resuscitate small and regional economies. "Wind Energy Basics" offers a how-to for home-ba...

The Solubility of Ozone in Deionized Water and its Cleaning Efficiency

Energy Technology Data Exchange (ETDEWEB)

Han, J.H.; Park, J.G. [Hanyang University, Seoul (Korea, Republic of); Kwak, Y.S. [Hanyang Technology Co., Ltd., Ansan (Korea, Republic of)

1998-06-01

The purpose of this study was to investigate the behavior of ozone in DI water and the reaction with wafers during the semiconductor wet cleaning process. The solubility of ozone in DI water was not only dependent on the temperature but also directly proportional to the input concentration of ozone. The lower the initial ozone concentration and the temperature, the longer the half-life time of ozone. The reaction order of ozone in DI water was calculated to be around 1.5. The redox potential reached a saturation value in 5min and slightly increased as the input ozone concentrations increased. The completely hydrophilic surface was created in 1min when HF etched silicon wafer was cleaned in ozonized DI water containing higher ozone concentrations than 2ppm. Spectroscopic ellipsometry measurements showed that the chemical oxide formed by ozonized DI water was measured to be thicker than that by piranha solution. The wafers contaminated with a non-ionic surfactant were more effectively cleaned in ozonized DI water than in piranha and ozonized piranha solutions. (author). 19 refs., 11 figs., 1 tab.

ZnO nanocrystals on SiO2/Si surfaces thermally cleaned in ultrahigh vacuum and characterized using spectroscopic photoemission and low energy electron microscopy

International Nuclear Information System (INIS)

Ericsson, Leif K. E.; Magnusson, Kjell O.; Zakharov, Alexei A.

2010-01-01

Thermal cleaning in ultrahigh vacuum of ZnO nanocrystals distributed on SiO 2 /Si surfaces has been studied using spectroscopic photoemission and low energy electron microscopy (SPELEEM). This study thus concern weakly bound ZnO nanocrystals covering only 5%-10% of the substrate. Chemical properties, crystallinity, and distribution of nanocrystals are used to correlate images acquired with the different techniques showing excellent correspondence. The nanocrystals are shown to be clean enough after thermal cleaning at 650 deg. C to be imaged by LEEM and x-ray PEEM as well as chemically analyzed by site selective x-ray photoelectron spectroscopy (μ-XPS). μ-XPS shows a sharp Zn 3d peak and resolve differences in O 1s states in oxides. The strong LEEM reflections together with the obtained chemical information indicates that the ZnO nanocrystals were thermally cleaned, but do not indicate any decomposition of the nanocrystals. μ-XPS was also used to determine the thickness of SiO 2 on Si. This article is the first to our knowledge where the versatile technique SPELEEM has been used to characterize ZnO nanocrystals.

Researches in increase of efficiency of electrokinetic process of ground cleaning from radionuclides

International Nuclear Information System (INIS)

Prozorov, L.B.; Shcheglov, M.Y.; Nikolaevsky, V.B.; Tkachenko, A.V.

2003-01-01

Potentially perspective method of decontamination of ground is electrokinetic method, which basic advantage consists in an opportunity of its application for clearing ground with low filtering by ability directly on a place of local contaminated (in situ). Thus moving the large volumes of the contaminated ground is excluded. Base of this method is the processes of electromigration and electro-osmotic, proceeding in a contaminated ground lay at imposing an electrical field of a constant current. Electrokinetic method of cleaning of ground from radionuclides provides their transfer in water-soluble, mobile form, carry as positive or negative ions under influence of an electrical field into electrode chambers with their subsequent recycling.Electrokinetic method in practice can be realized as follows: in the contaminated ground establish special electrode devices, fill their electrolyte and connect to a source of a constant current. Formed in the anode device as a result of electrochemical decomposition of water the ions of hydrogen under action of an electrical field move to the cathode, thus cooperate with a ground and superside cations of radioactive elements. Desorbed cations of contaminate act in catholyte, which periodically or continuously is exposed to clearing, for example, on sorption column. Last years the experts MosNPO Radon carry out complex researches directed on development of electrokinetic technology of cleaning ground from radionuclides and heavy metals. To the present time laboratory and bench tests of electrokinetic method are carried out. The basic attention at study of process of cleaning was given to objects contaminated Cs-137, most difficult recovery an element, which is strongly fixed by clay minerals and can enter into crystal structure. (authors)

Construction technique for a chemical plant (III)

International Nuclear Information System (INIS)

1978-08-01

This book mentions design of instrumentation and construction for a chemical plant, which deals with the change of instrumentation, construction, choice of material test, construction of thermal insulation work for a chemical plant, about classification and main materials, the problems on construction, painting plan and construction for a chemical plant such as paint and painting, safety and hygiene, cleaning of a chemical plant on the time for washing and decision of the way of washing, start up test for a chemical plant such as introduction of the check, construction and repair.

Chemical dynamics of acidity and heavy metals in a mine water-polluted soil during decontamination using clean water.

Science.gov (United States)

Chen, A; Lin, C; Lu, W; Ma, Y; Bai, Y; Chen, H; Li, J

2010-03-15

A column leaching experiment was conducted to investigate the chemical dynamics of the percolating water and washed soil during decontamination of an acidic mine water-polluted soil. The results show that leaching of the contaminated soil with clean water rapidly reduced soluble acidity and ion concentrations in the soils. However, only soil column was eliminated after 30 leaching cycles. It is likely that the stored acidity continues to be released to the percolating water over a long period of time. During the column leaching, dissolved Cu and Pb were rapidly leached out, followed by mobilization of colloidal Cu and Pb from the exchangeable and the oxide-bound fractions as a result of reduced ionic strength in the soil solution. The soluble Fe contained in the soil was rare, probably because the soil pH was not sufficiently low; marked mobility of colloidal Fe took place after the ionic strength of the percolating water was weakened and the mobilized Fe was mainly derived from iron oxides. In contrast with Cu, Pb and Fe, the concentration of leachate Zn and Mn showed a continuously decreasing trend during the entire period of the experiment. (c) 2009 Elsevier B.V. All rights reserved.

Basic research needs for management and disposal of DOE wastes

International Nuclear Information System (INIS)

Grazis, B.M.; Schulz, W.W.

1991-04-01

This document was chartered by the Department of Energy (DOE), Office of Energy Research. It identifies and describes 87 basic research needs in support of advanced technology for management and disposal of Department of Energy radioactive, hazardous chemical, and mixed wastes. A team of scientists and engineers from several DOE laboratories and sites, from academia, and from industry identified and described the basic research needs called out in this report. Special efforts were made to ensure that basic research needs related to management and disposal of any hazardous chemical wastes generated at nonnuclear DOE sites and facilities were properly identified. It is hoped that scientists in both DOE and nongovernment laboratories and institutions will find this document useful when formulating research efforts relevant to waste management and disposal. For management and disposal of DOE radioactive and mixed wastes, basic research needs are identified in nine separate action areas. Basic research needs for management and disposal of DOE hazardous chemical wastes are identified in five action areas. Sufficient description and background information are provided in the report for each particular research need to enable qualified and imaginative scientists to conceive research efforts and programs that will meet the need. 28 refs., 7 tabs

[Exposure to hazardous chemical substances in furniture industry].

Science.gov (United States)

Pośniak, Małgorzata; Kowalska, Joanna; Makhniashvili, Ivan

2005-01-01

The aim of the study was to assess the exposure to organic solvents in plants of the furniture industry. Studies were conducted in five furniture plants. Hazardous chemicals present in the air at workposts were determined by capillary gas chromatography with mass spectrometry and flame ionization detection. The analysis of air samples collected at the workposts allowed to identify the following chemicals occurring during varnishing and cleaning of furniture surface elements: acetone, butan-2-one, ethyl, isobutyl and methoxypropyl acetate, 4-methylpentan-2-on, toluene, ethylbenzene and xylenes. Indices characteristic of combined exposure ranged from 0.13 to 1.67 and exceeded the limit value at 21% of workposts. The results of the study indicate that chemicals present at representative workposts during the furniture production are harmful to health of workers, especially those involved in varnishing and cleaning of furniture elements.

Steam cleaning device

International Nuclear Information System (INIS)

Karaki, Mikio; Muraoka, Shoichi.

1985-01-01

Purpose: To clean complicated and long objects to be cleaned having a structure like that of nuclear reactor fuel assembly. Constitution: Steams are blown from the bottom of a fuel assembly and soon condensated initially at the bottom of a vertical water tank due to water filled therein. Then, since water in the tank is warmed nearly to the saturation temperature, purified water is supplied from a injection device below to the injection device above the water tank on every device. In this way, since purified water is sprayed successively from below to above and steams are condensated in each of the places, the entire fuel assembly elongated in the vertical direction can be cleaned completely. Water in the reservoir goes upward like the steam flow and is drained together with the eliminated contaminations through an overflow pipe. After the cleaning has been completed, a main steam valve is closed and the drain valve is opened to drain water. (Kawakami, Y.)

Ensuring clean air: Developing a clean air strategy for British Columbia

International Nuclear Information System (INIS)

1992-04-01

In 1992, a clean air strategy will be developed to incorporate views of British Columbians on ways to meet goals related to air quality. A discussion paper is presented to provide information to those interested in participation in developing this strategy. The paper gives information on air quality issues important to the province, including local air quality, urban smog, ozone layer depletion, and global climate change. The views and concerns expressed by stakeholders who attended the Clean Air Conference in 1991 are summarized. The process used to develop the clean air strategy is outlined and some outcomes to be anticipated from the strategy are suggested, including policies and priorities for action to ensure clean air. Air pollutants of concern are total reduced sulfur, mainly from pulp mills and gas processing plants; smoke from wood burning; sulfur dioxide from pulp mills and gas plants; hydrogen fluoride from aluminum smelting; ground-level ozone in urban areas; and acid rain. Elements of a clean air strategy include a smoke management policy, management strategies for greenhouse gases and ozone smog, ozone layer protection measures, regional air quality management plans, and long-term planning efforts in energy use, transportation modes, community design, and land use. 12 refs., 14 figs., 2 tabs

''How clean is clean'' in the United States federal and Washington State cleanup regulations

International Nuclear Information System (INIS)

Landau, H.G.

1993-01-01

The enactment of legislation and promulgation of implementing regulations generally involves the resolution of conflicting goals. Defining ''How Clean is Clean?'' in federal and state cleanup laws, regulations, and policies is no exception. Answering the ''How Clean is Clean?'' question has resulted in the identification of some important and sometimes conflicting goals. Continuing resolution of the following conflicting goals is the key to effect cleanup of hazardous waste sites: Expediency vs. Fairness; Flexibility vs. Consistency; Risk Reduction vs. Risk Causation; and Permanence vs. Cost Effectiveness

Impact of Acid Cleaning on the Performance of PVDF UF Membranes in Seawater Reverse Osmosis Pretreatment

KAUST Repository

Alsogair, Safiya

2016-01-01

required to maintain the characteristics of the membrane. This research was made with the purpose of investigating the effects of acid cleaning during chemically enhanced backwashing (CEB) on the performance of ultrafiltration (UF) membranes in seawater

Benchmarks of Global Clean Energy Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Sandor, Debra [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chung, Donald [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mann, Margaret [National Renewable Energy Lab. (NREL), Golden, CO (United States); Engel-Cox, Jill [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2017-01-01

The Clean Energy Manufacturing Analysis Center (CEMAC), sponsored by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE), provides objective analysis and up-to-date data on global supply chains and manufacturing of clean energy technologies. Benchmarks of Global Clean Energy Manufacturing sheds light on several fundamental questions about the global clean technology manufacturing enterprise: How does clean energy technology manufacturing impact national economies? What are the economic opportunities across the manufacturing supply chain? What are the global dynamics of clean energy technology manufacturing?

Diamond-cleaning investigations

International Nuclear Information System (INIS)

Derry, T.E.

Four parcels of diamonds which either had or had not been cleaned using the usual techniques, chiefly involving etch in molten potassium nitrate were supplied by De Beers Diamond Research Laboratories. Each parcel contained about 40 stones, amounting to about 10 carats. Half the diamonds in each parcel were cleaned by a standard procedure involving half an hours ultrasonic agitation in a 20% solution of the commercial detergent 'Contrad' which is effectively a surfactant and chelating agent. Visual comparisons by a number of observers who were not told the stones' histories, established that these diamonds generally had a more sparkling appearance after the cleaning procedure had been applied

National Alliance for Clean Energy Incubators New Mexico Clean Energy Incubator

Energy Technology Data Exchange (ETDEWEB)

Roberts, Suzanne S.

2004-12-15

The National Alliance for Clean Energy Incubators was established by the National Renewable Energy Laboratory (NREL) to develop an emerging network of business incubators for entrepreneurs specializing in clean energy enterprises. The Alliance provides a broad range of business services to entrepreneurs in specific geographic locales across the U.S. and in diverse clean energy technology areas such as fuel cells, alternative fuels, power generation, and renewables, to name a few. Technology Ventures Corporation (TVC) participates in the Alliance from its corporate offices in Albuquerque, NM, and from its sites in Northern and Southern New Mexico, California, and Nevada. TVC reports on the results of its attempts to accelerate the growth and success of clean energy and energy efficiency companies through its array of business support services. During the period from September 2002 through September 2004, TVC describes contributions to the Alliance including the development of 28 clients and facilitating capital raises exceeding $35M.

PETROLEUM-COLLECTING AND DISPERSING CHEMICALS FOR ...

African Journals Online (AJOL)

Preferred Customer

Films of petroleum origin reflecting sunlight rays hinder absorption of energy by water necessary for life ... Dispersing chemicals like mechanical clean-up methods have their own place in fighting oil spills. They are ... yellow color, and filtered.

Quantitative assessment of airborne exposures generated during common cleaning tasks: a pilot study

Directory of Open Access Journals (Sweden)

Perry Melissa J

2010-11-01

Full Text Available Abstract Background A growing body of epidemiologic evidence suggests an association between exposure to cleaning products with asthma and other respiratory disorders. Thus far, these studies have conducted only limited quantitative exposure assessments. Exposures from cleaning products are difficult to measure because they are complex mixtures of chemicals with a range of physicochemical properties, thus requiring multiple measurement techniques. We conducted a pilot exposure assessment study to identify methods for assessing short term, task-based airborne exposures and to quantitatively evaluate airborne exposures associated with cleaning tasks simulated under controlled work environment conditions. Methods Sink, mirror, and toilet bowl cleaning tasks were simulated in a large ventilated bathroom and a small unventilated bathroom using a general purpose, a glass, and a bathroom cleaner. All tasks were performed for 10 minutes. Airborne total volatile organic compounds (TVOC generated during the tasks were measured using a direct reading instrument (DRI with a photo ionization detector. Volatile organic ingredients of the cleaning mixtures were assessed utilizing an integrated sampling and analytic method, EPA TO-17. Ammonia air concentrations were also measured with an electrochemical sensor embedded in the DRI. Results Average TVOC concentrations calculated for 10 minute tasks ranged 0.02 - 6.49 ppm and the highest peak concentrations observed ranged 0.14-11 ppm. TVOC time concentration profiles indicated that exposures above background level remained present for about 20 minutes after cessation of the tasks. Among several targeted VOC compounds from cleaning mixtures, only 2-BE was detectable with the EPA method. The ten minute average 2- BE concentrations ranged 0.30 -21 ppm between tasks. The DRI underestimated 2-BE exposures compared to the results from the integrated method. The highest concentration of ammonia of 2.8 ppm occurred

ADULT BASIC LIFE SUPPORT ON NEAR DROWNING AT THE SCENE

Directory of Open Access Journals (Sweden)

Gd. Harry Kurnia Prawedana

2013-04-01

Full Text Available Indonesia is a popular tourist destination which has potential for drowning cases. Therefore, required knowledge of adult basic life support to be able to deal with such cases in the field. Basic life support in an act to maintain airway and assist breathing and circulation without the use of tools other than simple breathing aids. The most important factor that determines the outcome of drowning event is the duration and severity of hypoxia induced. The management of near drowning at the scene include the rescue of victim from the water, rescue breathing, chest compression, cleaning the vomit substances which allowing blockage of the airway, prevent loss of body heat, and transport the victim to nearest emergency department for evaluation and monitoring.

Sustainable development with clean coal

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-08-01

This paper discusses the opportunities available with clean coal technologies. Applications include new power plants, retrofitting and repowering of existing power plants, steelmaking, cement making, paper manufacturing, cogeneration facilities, and district heating plants. An appendix describes the clean coal technologies. These include coal preparation (physical cleaning, low-rank upgrading, bituminous coal preparation); combustion technologies (fluidized-bed combustion and NOx control); post-combustion cleaning (particulate control, sulfur dioxide control, nitrogen oxide control); and conversion with the integrated gasification combined cycle.

Clean Energy Progress Report

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

For the past several years, the IEA and others have been calling for a clean energy revolution to achieve global energy security, economic growth and climate change goals. This report analyses for the first time progress in global clean energy technology deployment against the pathways that are needed to achieve these goals. It provides an overview of technology deployment status, key policy developments and public spending on RDD&D of clean energy technologies.

Chemical kinetics and reaction dynamics

CERN Document Server

Houston, Paul L

2006-01-01

This text teaches the principles underlying modern chemical kinetics in a clear, direct fashion, using several examples to enhance basic understanding. It features solutions to selected problems, with separate sections and appendices that cover more technical applications.Each chapter is self-contained and features an introduction that identifies its basic goals, their significance, and a general plan for their achievement. This text's important aims are to demonstrate that the basic kinetic principles are essential to the solution of modern chemical problems, and to show how the underlying qu

Wet cleaning and surface characterization of Si{sub 1-x}Ge{sub x} virtual substrates after a CMP step

Energy Technology Data Exchange (ETDEWEB)

Abbadie, A. [CEA-LETI, Minatec, 17 Avenue des Martyrs, 38054 Grenoble Cedex 9 (France)], E-mail: alexandra.abbadie@soitec.fr; Hartmann, J.M. [CEA-LETI, Minatec, 17 Avenue des Martyrs, 38054 Grenoble Cedex 9 (France); Besson, P. [ST Microelectronics, 850 Rue Jean Monnet, 38 921 Crolles Cedex (France); Rouchon, D.; Martinez, E.; Holliger, P.; Di Nardo, C. [CEA-LETI, Minatec, 17 Avenue des Martyrs, 38054 Grenoble Cedex 9 (France); Campidelli, Y. [ST Microelectronics, 850 Rue Jean Monnet, 38 921 Crolles Cedex (France); Billon, T. [CEA-LETI, Minatec, 17 Avenue des Martyrs, 38054 Grenoble Cedex 9 (France)

2008-08-30

New reactants such as ozone dissolved in ultra-pure water have been widely used the last few years instead of the original Radio Corporation of America (RCA) cleaning (which is a combination of the Standard Cleaning 1 (SC1) and the Standard Cleaning 2 (SC2)). In a first part of the study (Microelectron. Eng. 83 (2006) 1986), we had quantified the efficiency of a new cleaning sequence (that calls upon HF and H{sub 2}O/O{sub 3} solutions) on polished Si{sub 1-x}Ge{sub x} virtual substrates (x = 0.2-0.5). We are discussing here the surface morphology and wetability together with the oxide thickness and structure typically obtained after this so-called 'DDC-SiGe' wet cleaning. Flat surface morphologies are found after cleaning whatever the Ge content (from 20 to 50%). Typical root mean square roughness is around 0.4 nm. We have used X-ray Photoelectron Spectroscopy to determine the characteristics of the surface termination after this 'DDC-SiGe' cleaning. An oxide mainly composed of SiO{sub 2} is formed, with a low fraction of Ge sub-oxide and GeO{sub 2}. The distribution of chemical species is not that different from the one obtained after the use of a SC1 cleaning. However, the chemical oxide formed is slightly thicker. Such a HF/O{sub 3} cleaning leads, when used on thick Ge layers grown on Si, to the formation of a really thin Ge sub-oxide. Our oxidation model assumes a competition in O{sub 3} solutions between the oxidation rates of Si and Ge atoms (faster for Si) and the dissolution of the Ge oxide formed in solution. This mechanism, which implies the formation of a slightly porous oxide, is different from the one seeming to occur in SC1-based solutions. Indeed, the addition of surfactant in a SC1 solution modifies the oxidation rate compared to standard SC1 or O{sub 3}-based solutions, suggesting a diffusion of reactants towards the interface between the SiGe and the oxide in formation, assisted by the reactions of species within the cleaning

Clean Energy Policy Analysis: Impact Analysis of Potential Clean Energy Policy Options for the Hawaii Clean Energy Initiative (HCEI)

Energy Technology Data Exchange (ETDEWEB)

Busche, S.; Doris, E.; Braccio, R.; Lippert, D.; Finch, P.; O' Toole, D.; Fetter, J.

2010-04-01

This report provides detailed analyses of 21 clean energy policy options considered by the Hawaii Clean Energy Initiative working groups for recommendation to the 2010 Hawaii State Legislature. The report considers the impact each policy may have on ratepayers, businesses, and the state in terms of energy saved, clean energy generated, and the financial costs and benefits. The analyses provide insight into the possible impacts, both qualitative and quantitative, that these policies may have in Hawaii based on the experience with these policies elsewhere. As much as possible, the analyses incorporate Hawaii-specific context to reflect the many unique aspects of energy use in the State of Hawaii.

Laser cleaning of Rakowicze sandstone

NARCIS (Netherlands)

Nijland, T.G.; Wijffels, T.J.

2003-01-01

Decisions about the cleaning of natural stone should always be made within the awareness of direct and indirect damage that may be the result of cleaning. During the last decade, laser cleaning of objects and monuments of natural stone has become increasingly popular. Whereas a considerable amount

Tests of an environmental and personnel safe cleaning process for BNL accelerator and storage ring components

International Nuclear Information System (INIS)

Foerster, C.L.; Lanni, C.; Lee, R.; Mitchell, G.; Quade, W.

1996-10-01

A large measure of the successful operation of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL) for over a decade can be attributed to the cleaning of its UHV components during and after construction. A new UHV cleaning process, which had to be environmentally and personnel safe, was needed to replace the harsh, unfriendly process which was still in use. Dow Advanced Cleaning Systems was contracted to develop a replacement process without the use of harsh chemicals and which must clean vacuum surfaces as well as the existing process. Acceptance of the replacement process was primarily based on Photon Stimulated Desorption (PSD) measurements of beam tube samples run on NSLS beam line U10B. One meter long beam tube samples were fabricated from aluminum, 304 stainless steel and oxygen free copper. Initially, coupon samples were cleaned and passed preliminary testing for the proposed process. Next, beam tube samples of each material were cleaned, and the PSD measured on beam line U10B using white light with a critical energy of 487 ev. Prior to cleaning, the samples were contaminated with a mixture of cutting oils, lubricants, vacuum oils and vacuum grease. The contaminated samples were then baked. Samples of each material were also cleaned with the existing process after the same preparation. Beam tube samples were exposed to between 10 22 and 10 23 photons per meter for a PSD measurement. Desorption yields for H 2 , CO, CO 2 , CH 4 and H 2 O are reported for both the existing cleaning and for the replacement cleaning process. Preliminary data, residual gas scans, and PSD results are given and discussed. The new process is also compared with new cleaning methods developed in other laboratories

Surface cleaning in thin film technology

International Nuclear Information System (INIS)

Mattox, D.M.

1978-01-01

A ''clean surface'' is one that contains no significant amounts of undesirable material. This paper discusses the types and origin of various contaminants. Since cleaning is often equated with adhesion, the mechanisms of adhesion to oxide, metal, and organic surfaces are reviewed and cleaning processes for these surfaces are outlined. Techniques for monitoring surface cleaning are presented, and the importance of storage of clean surfaces is discussed. An extensive bibliography is given. 4 figs., 89 references

Chemical Biodynamics Division. Annual report 1979

Energy Technology Data Exchange (ETDEWEB)

1980-08-01

The Chemical Biodynamics Division of LBL continues to conduct basic research on the dynamics of living cells and on the interaction of radiant energy with organic matter. Many aspects of this basic research are related to problems of environmental and health effects of fossil fuel combustion, solar energy conversion and chemical/ viral carcinogenesis.

Chemical Equilibrium as Balance of the Thermodynamic Forces

OpenAIRE

Zilbergleyt, B.

2004-01-01

The article sets forth comprehensive basics of thermodynamics of chemical equilibrium as balance of the thermodynamic forces. Based on the linear equations of irreversible thermodynamics, De Donder definition of the thermodynamic force, and Le Chatelier's principle, new thermodynamics of chemical equilibrium offers an explicit account for multiple chemical interactions within the system. Basic relations between energetic characteristics of chemical transformations and reaction extents are bas...

Evaluation of Consumer Product Co-occurrence to Inform Chemical Exposure

Science.gov (United States)

Consumer products are an important target of chemical innovation. Used daily for personal hygiene, home care, disinfection and cleaning, consumer products provide a host of benefits, and also an efficient delivery vehicle for a variety of chemicals into our homes and bodies. Al...

Fire protection for clean rooms

International Nuclear Information System (INIS)

Kirson, D.

1990-01-01

The fire protection engineer often must decide what size fire can be tolerated before automatic fire suppression systems actuate. Is it a wastepaper basket fire, a bushel basket fire...? In the case of state-of-the-art clean rooms, the answer clearly is not even an incipient fire. Minor fires in clean rooms can cause major losses. This paper discusses what a clean room is and gives a brief overview of the unique fire protection challenges encountered. The two major causes of fire related to clean rooms in the semiconductor industry are flammable/pyrophoric gas fires in plastic ducts and polypropylene wet bench fires. This paper concentrates on plastic ductwork in clean rooms, sprinkler protection in ductwork, and protection for wet benches

CURE: Clean use of reactor energy

International Nuclear Information System (INIS)

1990-05-01

This paper presents the results of a joint Westinghouse Hanford Company (Westinghouse Hanford)-Pacific Northwest Laboratory (PNL) study that considered the feasibility of treating radioactive waste before disposal to reduce the inventory of long-lived radionuclides, making the waste more suitable for geologic disposal. The treatment considered here is one in which waste would be chemically separated so that long-lived radionuclides can be treated using specific processes appropriate for the nuclide. The technical feasibility of enhancing repository performance by this type of treatment is considered in this report. A joint Westinghouse Hanford-PNL study group developed a concept called the Clean Use of Reactor Energy (CURE), and evaluated the potential of current technology to reduce the long-lived radionuclide content in waste from the nuclear power industry. The CURE process consists of three components: chemical separation of elements that have significant quantities of long-lived radioisotopes in the waste, exposure in a neutron flux to transmute the radioisotopes to stable nuclides, and packaging of radionuclides that cannot be transmuted easily for storage or geologic disposal. 76 refs., 32 figs., 24 tabs

7 CFR 51.2083 - Clean.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Clean. 51.2083 Section 51.2083 Agriculture Regulations... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Almonds in the Shell Definitions § 51.2083 Clean. Clean means that the shell is...

Dry-cleaning of graphene

International Nuclear Information System (INIS)

Algara-Siller, Gerardo; Lehtinen, Ossi; Kaiser, Ute; Turchanin, Andrey

2014-01-01

Studies of the structural and electronic properties of graphene in its pristine state are hindered by hydrocarbon contamination on the surfaces. Also, in many applications, contamination reduces the performance of graphene. Contamination is introduced during sample preparation and is adsorbed also directly from air. Here, we report on the development of a simple dry-cleaning method for producing large atomically clean areas in free-standing graphene. The cleanness of graphene is proven using aberration-corrected high-resolution transmission electron microscopy and electron spectroscopy

Dry-cleaning of graphene

Energy Technology Data Exchange (ETDEWEB)

Algara-Siller, Gerardo [Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, Ulm University, Albert-Einstein-Allee 11, Ulm 89081 (Germany); Department of Chemistry, Technical University Ilmenau, Weimarer Strasse 25, Ilmenau 98693 (Germany); Lehtinen, Ossi; Kaiser, Ute, E-mail: ute.kaiser@uni-ulm.de [Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, Ulm University, Albert-Einstein-Allee 11, Ulm 89081 (Germany); Turchanin, Andrey [Faculty of Physics, University of Bielefeld, Universitätsstr. 25, Bielefeld 33615 (Germany)

2014-04-14

Studies of the structural and electronic properties of graphene in its pristine state are hindered by hydrocarbon contamination on the surfaces. Also, in many applications, contamination reduces the performance of graphene. Contamination is introduced during sample preparation and is adsorbed also directly from air. Here, we report on the development of a simple dry-cleaning method for producing large atomically clean areas in free-standing graphene. The cleanness of graphene is proven using aberration-corrected high-resolution transmission electron microscopy and electron spectroscopy.

Efficient methods of piping cleaning

Directory of Open Access Journals (Sweden)

Orlov Vladimir Aleksandrovich

2014-01-01

Full Text Available The article contains the analysis of the efficient methods of piping cleaning of water supply and sanitation systems. Special attention is paid to the ice cleaning method, in course of which biological foil and various mineral and organic deposits are removed due to the ice crust buildup on the inner surface of water supply and drainage pipes. These impurities are responsible for the deterioration of the organoleptic properties of the transported drinking water or narrowing cross-section of drainage pipes. The co-authors emphasize that the use of ice compared to other methods of pipe cleaning has a number of advantages due to the relative simplicity and cheapness of the process, economical efficiency and lack of environmental risk. The equipment for performing ice cleaning is presented, its technological options, terms of cleansing operations, as well as the volumes of disposed pollution per unit length of the water supply and drainage pipelines. It is noted that ice cleaning requires careful planning in the process of cooking ice and in the process of its supply in the pipe. There are specific requirements to its quality. In particular, when you clean drinking water system the ice applied should be hygienically clean and meet sanitary requirements.In pilot projects, in particular, quantitative and qualitative analysis of sediments adsorbed by ice is conducted, as well as temperature and the duration of the process. The degree of pollution of the pipeline was estimated by the volume of the remote sediment on 1 km of pipeline. Cleaning pipelines using ice can be considered one of the methods of trenchless technologies, being a significant alternative to traditional methods of cleaning the pipes. The method can be applied in urban pipeline systems of drinking water supply for the diameters of 100—600 mm, and also to diversion collectors. In the world today 450 km of pipelines are subject to ice cleaning method.Ice cleaning method is simple

Clean and polymer-free transfer of CVD-grown graphene films on hexagonal boron nitride substrates

Science.gov (United States)

Fujihara, Miho; Ogawa, Shun; Yoshimura, Shintaro; Inoue, Ryosuke; Maniwa, Yutaka; Taniguchi, Takashi; Watanabe, Kenji; Shinohara, Hisanori; Miyata, Yasumitsu

2017-05-01

This report describes the development of a solution-assisted, polymer-free transfer method and the characterization of chemical vapor deposition (CVD)-grown graphene on hexagonal boron nitride. Raman analysis reveals that polymer-free samples have small variations in G- and 2D-mode Raman frequencies and are minimally affected by charge doping as observed for clean exfoliated graphene. Electrical measurements indicate that charge doping, hysteresis, and carrier scattering are suppressed in polymer-free samples. The results demonstrate that this method provides a simple and effective way to prepare clean heterostructures of CVD-grown, large-area graphene and other two-dimensional materials.

An experimental evaluation on air purification performance of Clean-Air Heat Pump (CAHP) air cleaner

DEFF Research Database (Denmark)

Sheng, Ying; Fang, Lei; Sun, Yuexia

2018-01-01

was 96.8%, which indicated that the most of gaseous pollutants were not accumulated in the CAHP. The regeneration temperature for the wheel could affect the air purification performance of CAHP. At 70 °C of regeneration temperature, the air-cleaning efficiency reached 96.7%. Up to 70% of the outdoor air......The escalation of energy consumption in buildings and heightened concerns about acceptable indoor air quality stimulate interest in the usage of air cleaner as an adjunct for indoor environmental conditioning. A regenerative desiccant wheel integrated into a ventilation system termed Clean-Air Heat...... Pump (CAHP) can improve the air quality during the process of dehumidification without using additional energy. An experimental study in a field lab was performed to investigate the air cleaning performance of CAHP. Photoacoustic gas analyzer-INNOVA was used to characterize chemical removal of indoor...

Construction technique for a chemical plant (I)

International Nuclear Information System (INIS)

1978-08-01

This book mentions the order of plant construction, building plant and related regulations, basic engineering design data, provide of equipment, plan and management on building plant, quality control, the budget and contract for building plant, public works for building chemical plant like road construction, basic plan and building for a chemical plant, introduction and principle on foundation improvement method, including pile foundation and design for footing, construction and installation for a chemical plant and a rotary machine for a chemical plant.

An assessment of alternatives for replacing Freon 113 in bench type electrical circuit board cleaning at Fermi National Accelerator Laboratory

International Nuclear Information System (INIS)

Isakson, K.; Vessell, A.L.

1994-07-01

Fermilab is presently phasing out all solvents containing Freon-113 (CFC-113) as part of the continuing Waste Minimization Program. These solvents are used primarily in cleaning the flux off of electronic circuit boards after soldering, specifically in bench type work. Title VI of the Clean Air Act mandates a production phase-out for ozone depleting substances, like CFC-113, by the year 2000. Our study addresses this issue by evaluating and choosing alternative non-CFC solvents to replace the CFC-1 13 solvents at Fermilab. Several potential non-CFC cleaning solvents were tested. The evaluation took place in three parts: controlled experimental evaluation, chemical composition evaluation, and employee performed evaluation. First, we performed a controlled nine-step procedure with the potential solvents where each was evaluated in categories such as cleaning effectiveness, odor, residue, type of output and drying time. Next, we listed the chemical composition of each solvent. We noted which solvents contained hydrochlorofluorocarbons because they are targeted for phase-out in the future and will be recognized as interim solutions only. Finally, after preliminary testing, five solvents were chosen as the best options. These solvents were sent to be tested by Fermilab employees who use such materials. Their opinions are valuable not only because they are knowledgeable in this field, but also because they will be using the solvents chosen to replace the CFC-113 solvents. The results favored two ''best alternatives'': Safezone Solvent Flux Remover by Miller-Stephenson and E-Series CFC Free Flux-Off 2000 by Chemtech. Another possible solution also pursued is the no-clean solder option. In our study, we were not able to thoroughly investigate the many types of no-clean solders because of time and financial constraints. The testing that was done, however, showed that no-clean solder was a viable alternative in many cases

Clean Coal Program Research Activities

Energy Technology Data Exchange (ETDEWEB)

Larry Baxter; Eric Eddings; Thomas Fletcher; Kerry Kelly; JoAnn Lighty; Ronald Pugmire; Adel Sarofim; Geoffrey Silcox; Phillip Smith; Jeremy Thornock; Jost Wendt; Kevin Whitty

2009-03-31

Although remarkable progress has been made in developing technologies for the clean and efficient utilization of coal, the biggest challenge in the utilization of coal is still the protection of the environment. Specifically, electric utilities face increasingly stringent restriction on the emissions of NO{sub x} and SO{sub x}, new mercury emission standards, and mounting pressure for the mitigation of CO{sub 2} emissions, an environmental challenge that is greater than any they have previously faced. The Utah Clean Coal Program addressed issues related to innovations for existing power plants including retrofit technologies for carbon capture and sequestration (CCS) or green field plants with CCS. The Program focused on the following areas: simulation, mercury control, oxycoal combustion, gasification, sequestration, chemical looping combustion, materials investigations and student research experiences. The goal of this program was to begin to integrate the experimental and simulation activities and to partner with NETL researchers to integrate the Program's results with those at NETL, using simulation as the vehicle for integration and innovation. The investigators also committed to training students in coal utilization technology tuned to the environmental constraints that we face in the future; to this end the Program supported approximately 12 graduate students toward the completion of their graduate degree in addition to numerous undergraduate students. With the increased importance of coal for energy independence, training of graduate and undergraduate students in the development of new technologies is critical.

Laser paper cleaning: the method of cleaning historical books

Science.gov (United States)

Zekou, Evangelini; Tsilikas, Ioannis; Chatzitheodoridis, Elias; Serafetinides, Alexander A.

2016-01-01

Conservation of cultural heritage treasures is the most important issue for transferring knowledge to the public through the next generation of students, academics, and researchers. Although this century is authenticating e-books and information by means of electronic text, still historical manuscripts as content as well as objects are the main original recourses of keeping a record of this transformation. The current work focuses on cleaning paper samples by the application of pulsed light, which is interventional. Experiments carried out using paper samples that are artificially colonized with Ulocladium chartarum. Paper is treated by Nd:YAG laser light. The available wavelength is 1064 nm, at various fluences, repetition rates and number of pulses. Two types of paper are stained with fungi colonies, which grow on substrates of clean paper, as well as on paper with ink text. The first type of paper is Whatman No.1056, which is closer to pure cellulose. The second type of paper is a page of a cultural heritage book published in 1926. Cleaning is performed using laser irradiation, thus defining the damage threshold of each sample. The treatment on paper Watman showed a yellowing, especially on areas with high concentration of fungi. The second sample was more durable to the exposure, performing the best results at higher fluences. Eventually, the paper samples are characterized, with optical microscopy and SEM/EDX analyses, prior to and after cleaning.

Twenty-second DOE/NRC nuclear air cleaning and treatment conference

International Nuclear Information System (INIS)

Bellamy, R.R.; Moeller, D.W.; First, M.W.

1992-01-01

The Twenty-Second Department of Energy/Nuclear Regulatory Commission Nuclear Air Cleaning and Treatment Conference was held Aug. 24-27, 1992, in Denver, Colo. A total of 224 air-cleaning specialists attended the conference. The United States and 12 foreign countries were represented, and the specialists were affiliated with government agencies, educational institutions, and all aspects of the nuclear industry, including utilities, architect engineers, equipment suppliers, and consultants. Several major topics were discussed, similar to areas covered at previous conferences: chemical processing off-gas cleaning; particulate filler developments, including filter testing, performance, and response to physical stress,adsorber testing and performance, including laboratory and in-place testing; waste management; system operation; codes and standards; and advanced nuclear power plants. The conference continued to provide an effective forum for direct interchange of information of both a practical and theoretical nature. International participation and interest continues, as evidenced by over 40% of the papers being sponsored by foreign interests and almost 20% of the attendees being from outside the United States. The potential for new, safer nuclear plants of an advanced design was an optimistic note during the conference. Regulatory authorities are playing a major role in providing guidance in the development of safety goals and other technical criteria for these new installations

Capillary-Force-Assisted Clean-Stamp Transfer of Two-Dimensional Materials.

Science.gov (United States)

Ma, Xuezhi; Liu, Qiushi; Xu, Da; Zhu, Yangzhi; Kim, Sanggon; Cui, Yongtao; Zhong, Lanlan; Liu, Ming

2017-11-08

A simple and clean method of transferring two-dimensional (2D) materials plays a critical role in the fabrication of 2D electronics, particularly the heterostructure devices based on the artificial vertical stacking of various 2D crystals. Currently, clean transfer techniques rely on sacrificial layers or bulky crystal flakes (e.g., hexagonal boron nitride) to pick up the 2D materials. Here, we develop a capillary-force-assisted clean-stamp technique that uses a thin layer of evaporative liquid (e.g., water) as an instant glue to increase the adhesion energy between 2D crystals and polydimethylsiloxane (PDMS) for the pick-up step. After the liquid evaporates, the adhesion energy decreases, and the 2D crystal can be released. The thin liquid layer is condensed to the PDMS surface from its vapor phase, which ensures the low contamination level on the 2D materials and largely remains their chemical and electrical properties. Using this method, we prepared graphene-based transistors with low charge-neutral concentration (3 × 10 10 cm -2 ) and high carrier mobility (up to 48 820 cm 2 V -1 s -1 at room temperature) and heterostructure optoelectronics with high operation speed. Finally, a capillary-force model is developed to explain the experiment.

Summary report of the Banff clean energy dialogue : towards a truly Canadian clean energy strategy

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

A clean energy strategy will allow Canada to seize opportunities for prosperity in a low-carbon future, while also contributing to the country's economic growth. This report outlined the conclusions drawn by representatives of major energy corporations and policy-makers who gathered to discuss Canada's clean energy plans for the future. Attendants at the meeting concluded that energy conservation and energy efficiency will play a prominent role in a successful clean energy strategy. However, a price on carbon is needed to emphasize the fundamental relationship between energy and the environment. A successful strategy will feature the following 4 overarching principles: (1) economic opportunity, (2) social responsibility, (3) environmental stewardship, and (4) international strategy in relation to trade and development of new markets. The role that federal, provincial and municipal governments will play in developing and implementing the strategy was also presented. The meeting was divided into the following 6 working sessions: (1) global context for a clean energy strategy, (2) why a Canadian clean energy strategy? Why now?, (3) key pillars of a Canadian clean energy strategy, (4) key building blocks of a national clean energy strategy, (5) a balanced Canadian framework, and (6) next steps. 1 fig.

Thermalhydraulic assessment of the Pickering NGS 'B' feed and bleed system for the hot boiler chemical clean (Siemens Process)

International Nuclear Information System (INIS)

Lorencez, Carlos M.

2000-01-01

The Hot Boiler Chemical Clean (HBCC) process from Siemens, to be used in PNGS, requires that the Heat Transport System (HTS) temperature be maintained in the range 160 to 170 o C for several days. To achieve these thermalhydraulic condition, the core decay power and the pump power of the main circulating pumps in a 3-3 configuration are employed to warm up the HTS from approximately 38 o C to 170 o C. At this point, high Bleed bias is applied to the signal of the HTS pressure controller to provide high Feed and Bleed flows, which are used to control the HTS temperature by means of the Bleed Cooler. To address any concern posed by these infrequently used HTS thermalhydraulic conditions, a detailed thermalhydraulic model of the Feed and Bleed System, that also includes the Gland Supply, Gland Return and Purification systems, was developed for the TUF code to determine the suitability of the Feed and Bleed System to conduct the HBCC. The model was then used to estimate the parameters such as Feed and Bleed flows, valve openings, pressure and temperature distributions throughout the Feed and Bleed System required for the application of HBCC. (author)

A study of drying and cleaning methods used in preparation for fluorescent penetrant inspection - Part II

International Nuclear Information System (INIS)

Brasche, L.; Lopez, R.; Larson, B.

2003-01-01

Fluorescent penetrant inspection is the most widely used method for aerospace components such as critical rotating components of gas turbine engines. Successful use of FPI begins with a clean and dry part, followed by a carefully controlled and applied FPI process, and conscientious inspection by well trained personnel. A variety of cleaning methods are in use for cleaning of titanium and nickel parts with selection based on the soils or contamination to be removed. Cleaning methods may include chemical or mechanical methods with sixteen different types studied as part of this program. Several options also exist for use in drying parts prior to FPI. Samples were generated and exposed to a range of conditions to study the effect of both drying and cleaning methods on the flaw response of FPI. Low cycle fatigue (LCF) cracks were generated in approximately 40 nickel and 40 titanium samples for evaluation of the various cleaning methods. Baseline measurements were made for each of the samples using a photometer to measure sample brightness and a UVA videomicroscope to capture digital images of the FPI indications. Samples were exposed to various contaminants, cleaned and inspected. Brightness measurements and digital images were also taken to compare to the baseline data. A comparison of oven drying to flash dry in preparation for FPI has been completed and will be reported in Part I. Comparison of the effectiveness of various cleaning methods for the contaminants will be presented in Part II. The cleaning and drying studies were completed in cooperation with Delta Airlines using cleaning, drying and FPI processes typical of engine overhaul processes and equipment. The work was completed as part of the Engine Titanium Consortium and included investigators from Honeywell, General Electric, Pratt and Whitney, and Rolls Royce

A study of drying and cleaning methods used in preparation for fluorescent penetrant inspection - Part I

International Nuclear Information System (INIS)

Brasche, L.; Lopez, R.; Larson, B.

2003-01-01

Fluorescent penetrant inspection is the most widely used method for aerospace components such as critical rotating components of gas turbine engines. Successful use of FPI begins with a clean and dry part, followed by a carefully controlled and applied FPI process, and conscientious inspection by well trained personnel. A variety of cleaning methods are in use for cleaning of titanium and nickel parts with selection based on the soils or contamination to be removed. Cleaning methods may include chemical or mechanical methods with sixteen different types studied as part of this program. Several options also exist for use in drying parts prior to FPI. Samples were generated and exposed to a range of conditions to study the effect of both drying and cleaning methods on the flaw response of FPI. Low cycle fatigue (LCF) cracks were generated in approximately 40 nickel and 40 titanium samples for evaluation of the various cleaning methods. Baseline measurements were made for each of the samples using a photometer to measure sample brightness and a UVA videomicroscope to capture digital images of the FPI indications. Samples were exposed to various contaminants, cleaned and inspected. Brightness measurements and digital images were also taken to compare to the baseline data. A comparison of oven drying to flash dry in preparation for FPI has been completed and will be reported in Part I. Comparison of the effectiveness of various cleaning methods for the contaminants will be presented in Part II. The cleaning and drying studies were completed in cooperation with Delta Airlines using cleaning, drying and FPI processes typical of engine overhaul processes and equipment. The work was completed as part of the Engine Titanium Consortium and included investigators from Honeywell, General Electric, Pratt and Whitney, and Rolls Royce

Underwater cleaning techniqued used for removal of zebra mussels at the FitzPatrick Nuclear Power Plant

International Nuclear Information System (INIS)

Hobbs, B.; Kahabka, J.

1995-01-01

This paper discusses the use of a mechanical brush cleaning technology recently used to remove biofouling from the Circulating Water (CW) System at New York Power Authority's James A. FitzPatrick Nuclear Power Plant. The FitzPatrick plant had previously used chemical molluscicide to treat zebra mussels in the CW system. Full system treatment was performed in 1992 with limited forebay/screenwell treatment in 1993. The New York Power Authority (NYPA) decided to conduct a mechanical cleaning of the intake system in 1994. Specific project objectives included: (1) Achieve a level of surface cleaniness greater than 98%; (2) Remove 100% of debris, both existing sediment and debris generated as a result of cleaning; (3) Inspect all surfaces and components, identifying any problem areas; (4) Complete the task in a time frame within the 1994-95 refueling outage schedule window, and; (5) Determine if underwater mechanical cleaning is a cost-effective zebra mussel control method suitable for future application at FitzPatrick. A pre-cleaning inspection, including underwater video photography, was conducted of each area. Cleaning was accomplished using diver-controlled, multi-brush equipment included the electro-hydraulic powered Submersible Cleaning and Maintenance Platform (SCAMP), and several designs of hand-held machines. The brushes swept all zebra mussels off surfaces, restoring concrete and metal substrates to their original condition. Sensitive areas including pump housings, standpipes, sensor piping and chlorine injection tubing, were cleaned without degradation. Submersible vortex vacuum pumps were used to remove debris from the cavity. More than 46,000 ft 2 of surface area was cleaned and over 460 cubic yards of dewatered debris were removed. As each area was completed, a post-clean inspection with photos and video was performed

Two-step chemical decontamination technology

International Nuclear Information System (INIS)

Rankin, W.N.

1992-01-01

An improved two-step chemical decontamination technique was recently developed at INEL. This memorandum documents the addition of this technology to the SRTC arsenal of decontamination technology. A two-step process using NAOH, KMnO 4 followed by HNO 3 was used for cleaning doorstops (small casks) in the SRTC High Level Caves in 1967. Subsequently, more aggressive chemical techniques have been found to be much more effective for our applications. No further work on two-step technology is planned