• Journal of Conservation Science
• /
• v.30 no.1
• /
• pp.95-101
• /
• 2014

Silver objects tarnish with black from reaction with sulfurous acid or hydrogen sulfide of atmospheric. Blackening of silver objects results from formation of silver sulfide($Ag_2O$) on the surface. Silver sulfide usually is usually removed by conservation treatment. There are several cleaning methods such as chemical, electrochemical and micro-abrasion cleaning, but all of them consume silver. This study investigated the safe and effective parameter of laser cleaning by test on silver coupons. Laser cleaning is a selective process for the removal of specific substances. At first, laser cleaning applied to plain silver coupons, which were not corroded, to find out the safe range of laser energy density. From results, plain silver coupons were not changed at 1064nm below $4.00J/cm^2$ and at 532nm below $2.39J/cm^2$. The corrosion layer(silver sulfide) of artifical corroded silver coupons was removed at 1064nm with $2.39J/cm^2$ by 5~10 pulses and at 532nm with $1.19J/cm^2$ by 5~10 pulses. The removal thickness of corrosion layer was about 13-25nm per a laser pulse using AES analysis. In addition, laser cleaning tested the tarnish silver rings based on the results of silver coupons. As a result of test, the black surface were clean successfully and gave luster of silver, which showed the application possibility of laser cleaning for silver objects.

• Journal of Food Hygiene and Safety
• /
• v.38 no.4
• /
• pp.228-235
• /
• 2023

Peanut is a well-known food allergen that causes adverse reactions ranging from mild urticaria to life-threatening anaphylaxis. Consumers suffering from peanut allergies should thus avoid consuming undeclared peanuts in processed foods. Therefore, effective cleaning methods are needed to remove food allergens from manufacturing facilities. To address this, wet cleaning methods with washing water at different temperatures, abstergents (peracetic acid, sodium bicarbonate, dilute sodium hypochlorite, detergent), and cleaning tools (brush, sponge, paper towel, and cotton) were investigated to remove peanuts from materials used in food manufacture, including plastics, wood, glass, and stainless steel. Peanut butter was coated on the surface of the glass, wood, stainless steel, and plastic for 30 min and cleaned using wet cleaning. The peanut residue on the cleaned surfaces was swabbed and determined using an optimized enzyme-linked immunosorbent assay (ELISA). Cleaning using a brush and hot water above 50℃ showed an effective reduction of peanut residue from the surface. However, removing peanuts from wooden surfaces was complicated. These results provide information for selecting appropriate materials in food manufacturing facilities and cleaning methods to remove food allergens. Additionally, the cleaning methods developed in this study can be applied to further research on removing other food allergens.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2012.06a
• /
• pp.194-195
• /
• 2012

• Korean Journal of Plant Resources
• /
• v.19 no.2
• /
• pp.204-208
• /
• 2006

Soybean sprout decay during its culture should be one of serious problems. The study was carried out to clarify the effect of water imbibition and acetic acid treatments on growth and morphological characters of the soybean sprouts. The soybean seeds of 3 cultivars (cv. Eunhakong, Pungsannamulkong and Junjery) imbibed in pure water or 0.l% acetic acid for 3 minutes before soaked for 6 hours into 1 ppm BA solution and aerated for 3 hours immediately before 6 day culture. On the 6th day, the sprouts were classified into 4 categories on the base of hypocotyl length; > 7cm, 4 to 7cm, > 4cm and not germinated and seed floating rate, their morphological characters, fresh fraction weights and productivity were measured. The best water imbibition for seed cleaning was to soak the seeds for 5 minutes and then to aerate soak them for 40 minutes. In Pungsannamulkong and Junjery, percentage of the sprouts with hypocotyls of longer than 4 cm was higher in water imbibition than in acetic acid treatment for seed disinfection although in Eunhakong there was no significant difference between the two treatments. Eunhakong and Junjery had greater lateral root formation rate and its number per sprout in water imbibition than in acetic acid treatment but Pungsannamulkong showed reverse result. Eunhakong and Pungsannamulkong, furthermore, had more total fresh weight in acetic acid treatment than in water imbibition but Junjery showed reverse result, although there was no significant difference between the two treatments in productivity of mass production system.

• Journal of Conservation Science
• /
• v.25 no.4
• /
• pp.451-464
• /
• 2009

To do conservation for ceramics, sometimes it needs to clean the ceramics chemically to remove stains on the ceramics, which should be performed with caution. This study will provide quantitative data about the extraction characteristics of major elements from ceramics through the soaking test to evaluate the stability of ceramic cleaning agents. As soft textured pottery(fired at $700^{\circ}C$) had high absorption, it showed higher extraction characteristics in short soaking time. Especially the strong acid among chemical cleaning agents caused the expoliation and the color change on the surface of soft textured pottery. But these color change had no effect on the physical characteristics of soft textured pottery. The hard textured pottery(fired at $1,000^{\circ}C$) is relatively stable in the cleaning agent because it is ascertained the extraction of that was not enough and also it had little chromatic and physical change by strong acid. Porcelains(Celadon, Whiteware and Puncheong ware) was safer than the soft textured pottery due to their low extraction. But it should take precautions to clean the porcelains with lots of cracklewares such like Puncheong ware chemically in connection with the extraction characteristics and their cracklewares.

• Journal of Microbiology
• /
• v.38 no.2
• /
• pp.99-104
• /
• 2000

Hydrogen peroxide has been used in cleaning the piping of an advanced high-purity water system that supplies ultra-high purity water (UHPW) for 16 megabyte DRAM semiconductor manufacturing. The level of hydrogen peroxide-resistant bacteria in UHPW water was monitored prior to and after disinfecting the piping with hydrogen peroxide. Most of the bacteria isolated after hydrogen peroxide disinfection were highly resistant to hydrogen peroxide. However, the percentage of resistant bacteria decreased with time. The hydrogen peroxide-resistant bacteria were identified as Micrococcus luteus, Bacillus cereus, Alcaligenes latus, Xanthomonas sp. and Flavobacterium indologenes. The susceptibility of the bacteria to hydrogen peroxide was tested as either planktonic cells or attached cells on glass. Attached bacteria as the biofilm on glass exhibited increased hydrogen peroxide resistnace, with the resistance increasing with respect to the age of the biofilm regrowth on piping after hydrogen peroxide treatment. In order to optimize the cleaning strategy for piping of the high-purity water system, the disinfecting effect of hydrogen preoxide and peracetic acid on the bacteria was evaluated. The combined use of hydrogen peroxide and peracetic acid was very effective in killing attached bacteria as well as planktonic bacteria.

• Textile Coloration and Finishing
• /
• v.18 no.2 s.87
• /
• pp.8-14
• /
• 2006

The pigment extraction of Opuntia ficus-indica has been conducted to develop useful natural dyes in place of synthetic dyes which are suspected to bring serious environmental pollutions. The dyeing ability on wool fabric by addition of ascorbic acid and several mordants were investigated by means of color measurement. In addition, the fastness of washing, perspiration, rubbing, light, dry cleaning, effect on bacterial reduction and UV-B protection were also investigated. From these investigation, it is suggested that the pigment extracted from Opuntia ficus-indica can be used as a source of natural dyes and the obtained result are as follows. 1. Maximum absorption band (${\lambda}max$) of Opuntia ficus-indica extract is 533nm. 2. The wool fabric dyed with Opuntia ficus-indica extract has stable color by the addition of ascorbic acid and is achieved with addition of 0.1% ascorbic acid, 0.5% several mordant, and three repeated dying at $50^{\circ}C$ for 1.5hr. 3. The wash fastness of the dyed wool fabric when it is washed with neutral detergent is more effective than alkaline detergent. The dry cleaning fastness of the dyed wool fabric is more excellent. In addition, the perspiration fastness of the dyed wool fabric is increased by mordanting method. And than the rubbing fastness of the dyed wool fabric is showed excellent under dryness and wetness. Light fastness of the dyed wool fabric, however is showed inferiority. 4. The wool fabric dyed with Opuntia ficus-indica extract is showed effective bacterial reduction and UV-B protection is increased remarkably.

• Resources Recycling
• /
• v.14 no.5 s.67
• /
• pp.40-44
• /
• 2005

The purified phosphoric acid was recovered from crude phosphoric acid with high contents of aluminium and molybdenum ions to reuse the acid as an etchant. In this work, solvent extraction was applied to recover the phosphoric acid from crude phosphoric acid. Phosphate was used as an extractant. Further cleaning and removing processes on the recovered phosphoric acid were conducted to eliminate the metallic ion impurities in the acid. The process parameters were successfully optimized, so that the finally purified acid contained less than 1 ppm of aluminium and molybdenum ion.

• Journal of Powder Materials
• /
• v.18 no.6
• /
• pp.517-525
• /
• 2011

In this study, the used DOCs, which could remove the air pollutants such as CO and HC in the exhaust gas from diesel vehicle, were remanufactured by various conditions. Their catalytic performances and characterization were also investigated. The remanufacturing process of the deactivated DOCs includes high temperature cleaning of incineration, ultrasonic cleaning for washing with acid/base solutions to remove deactivating materials deposited to the surface of the catalysts, and active component reimpregnation for reactivating catalytic activity of them. The catalytic performance tests of the remanufactured DOCs were carried out by the diesel engine dynamo systems and chassi dynamo systems in CVS-75 mode. All prepared catalysts were characterized by the optical microscopes, SEM, EDX, porosimeter and BET to investigate correlations between catalytic reactivity and surface characteristics of them. The remanufactured DOCs at various conditions showed the improved catalytic performances reaching to 90% of fresh DOC, which is attributed to remove the deactivating materials from the surface of the used DOC through the analysis of catalytic performance test and their characterization.

• The Research Journal of the Costume Culture
• /
• v.16 no.1
• /
• pp.158-165
• /
• 2008

The purpose of this study was to investigate the dyeing property and ultraviolet-cut ability on silk 100% and nylon 100% fabrics dyed with Rhus verniciflua extracts. This study was investigated K/S values, surface color, washing fastness, dry cleaning fastness and ultraviolet-cut ability of the silk and nylon fabrics dyed with Rhus verniciflua extracts under the various dyeing conditions. As mordanting were used Tin(II) Chloride dihydrate $(SnCl_2{\cdot}2H_2O)$, Copper(II) sulfate pentahydrate$(CuSO_5{\cdot}5H_2O)$, Iron(II)Chloride$(FeC_2{\cdot}4H_2O)$. pH was adjusted by sodium carbonate$(Na_2CO_3)$ and formic acid(HCOOH). The optimum dyeing temperature, dyeing time, and pH of the silk fabrics dyed with Rhus verniciflua extracts were $90^{\circ}C$, 100min, and in the nylon fabrics were $90^{\circ}C$, 45min. It were colored(munsell value) 6.4Y 7.5/4.1 in the silk fabrics and colored 4.3Y 6.6/5.9 in the nylon fabrics dyed with Rhus verniciflua extracts. Washing fastness and dry-cleaning fastness in the silk and nylon fabrics dyed with mordanting agent improved in $4{\sim}5$ grade. UV-A test showed that nylon fabrics a high rate of 92% with Rhus verniciflua extracts.