scholarly journals Use of ultrasound for cleaning of components of historical vehicles in Technical Museum in Brno

2020 ◽  
Vol 64 (3) ◽  
pp. 79-86
Author(s):  
K. Rapouch ◽  
M. Mrázek
Keyword(s):  
Water Drop ◽  
Bath Temperature ◽  
Cleaning Process ◽  
Fuel System ◽  
Dissolved Metals ◽  
Cleaning Efficiency ◽  
Ultrasound Frequency ◽  
Aas Method ◽  
Ultrasound Effect

Abstract In the collections of Technical Museum in Brno, large number of historical vehicles is placed. During the operation, parts of their motors are being fouled. Frequently, they become even immobile (e. g. due to a fouled fuel system). In this case, the method using ultrasound with a suitable concentrate appears as the most suitable. In fact, ultrasound works also in inaccessible places with large efficiency. Not only the chosen solution influences the cleaning efficiency, but also parameters as time, bath temperature and ultrasound frequency. The cleaning process was evaluated according to the volume of removed dirt and by observing wettability change using the measuring of contact angle of a water drop. The ultrasound shock waves influence the surface to a certain extent also mechanically. That is why, the ultrasound effect on defects in the structure was observed. The aggressivity of cleaning concentrates was evaluated on the ground of determination of dissolved metals in the baths by ET AAS method.

Mechanism of PVA Brush Loading with Ceria Particles during Post-CMP Cleaning Process

2021 ◽  
Vol 314 ◽  
pp. 259-263
Author(s):  
Samrina Sahir ◽  
Hwi Won Cho ◽  
Nagendra Prasad Yerriboina ◽  
Tae Gon Kim ◽  
Satomi Hamada ◽  
...  
Keyword(s):  
Electrostatic Attraction ◽  
Particle Removal ◽  
Cross Contamination ◽  
Cleaning Process ◽  
Particle Loading ◽  
Cleaning Efficiency ◽  
Solution Ph ◽  
Cleaning Solution ◽  
Oppositely Charged ◽  
Process Interaction

Brush scrubbing is a well-known post CMP cleaning process. Interaction between PVA brush and the particles removed during the process must be considered while designing a cleaning process. In this work, the effect of cleaning solution pH was investigated in terms of particle removal from the wafer and subsequent loading to the PVA brush nodule. Higher cleaning of particles from wafer was observed for pH 2 and 12 cleaning solutions and poor cleaning for pH 7 cleaning solution. In contrast, the brushes were loaded heavily for pH 7 compared to pH 2 and 12. Higher electrostatic attraction between oppositely charged PVA and ceria surfaces provided higher ceria particles loading to PVA brush in acidic and neutral cleaning solutions. This particle loading to PVA brush can further effect cleaning efficiency as well as cross-contamination.

Influence of deforming of common rail diesel injectors parts on the fuel injection process

2021 ◽  
pp. 4-12
Author(s):  
Keyword(s):  
High Pressures ◽  
Fuel Injection ◽  
Experimental Studies ◽  
Common Rail ◽  
Electronic Control ◽  
Fuel System ◽  
Fuel Supply ◽  
Injection Process ◽  
Injection Cycle

Experimental studies have revealed a significant impact of deformation of Сommon Rail injector parts on the fuel supply process. High pressures alter the structure of the fuel supply cy-cle. Theforward front of the fuel supply cycle begins with the stage of unloading the deformed parts of the injector. The rear front of the fuel supply cycle ends with the stage of deformation of the injector parts. The calculated and experimental determination of cyclic fuel supply gave similar results. The developed method of determining the duration of the injection cycle stages creates a basis for experimental verification of mathematical models. Keywords: injector, Common Rail, diesel, fuel system, electronic control, needle, fuel injection

scholarly journals Comparison of Vitros Dry Slide Technology for Determination of Lithium Ions with Other Methods

2006 ◽  
Vol 6 (2) ◽  
pp. 32-36
Author(s):  
Nafija Serdarević ◽  
Ivan Malešić ◽  
Franc Kozjek
Keyword(s):  
Reference Method ◽  
Absorption Spectrometry ◽  
Lithium Carbonate ◽  
T Test ◽  
Selective Electrode ◽  
Lithium Ions ◽  
Control Precision ◽  
Aas Method ◽  
Sera Samples

The lithium ions concentration in human serum was determined using Dry-slide technology Vitros 250 Analyser (Ortho Clinical Diagnostic), atomic absorption spectrometry (AAS) method Perkin Elmer 403 and ion-selective electrode (ISE) potentiometry AVL 9181. We compared lithium ions results in sample sera between these methods. Our reference method was AAS. We analyzed lithium ions concentration in 23 sera samples of patients after oral administration of lithium carbonate (3x 300mg) Jadran, Galen Laboratory Rijeka, by dry-slide technology, AAS and ISE methods. The quality control, precision, reproducibility and accuracy for Vitros dry slide technology were assessed. We established that the main difference between AAS method and dry slide technology was not statistically significant at p< 0.05 according to Student t-test. Therefore, the dry slide technology may be a useful alternative or it may even replace other methods, such as AAS. The main difference between dry slide technology and ISE methods was statistically significant at p<0.05 using Student t-test. By ISE method, we obtained considerably higher results, which may be explained by the presence of electrolytes or medicaments interfering with lithium ions.

Atomic Absorption Spectrophotometric Method for Determination of Water-Soluble Copper in Water-Insoluble Copper Fungicides: CIPAC Collaborative Study. Comparison with Bathocuproine Method

1981 ◽  
Vol 64 (1) ◽  
pp. 75-78
Author(s):  
F Sánchez Rasero ◽  
◽  
P G Balayannis ◽  
H P Beyers ◽  
E Celma ◽  
...  
Keyword(s):  
Atomic Absorption ◽  
Collaborative Study ◽  
The United States ◽  
Atomic Absorption Spectrophotometry ◽  
Water Soluble ◽  
Absorption Spectrophotometry ◽  
Aas Method ◽  
Standard Deviations ◽  
The Difference

Abstract An atomic absorption spectrophotometric (AAS) method was collaboratively studied by 8 laboratories from Africa, the United States, Australia, and Europe. The samples were dispersed in deionized water. After centrifuging and filtering, the water-soluble copper in the filtrate was acidified and measured by atomic absorption spectrophotometry, in an airacetylene flame, at 324.7 nm. The results from 7 laboratories were satisfactory and no unfavorable comments were received. Repeatability standard deviations ranged from 0.005 to 0.023, and reproducibility standard deviations ranged from 0.012 to 0.062. When compared with the bathocuproine method, the difference in bias between both methods is not significant. They were both adopted as full CIPAC methods, with the bathocuproine method as the referee method. Both methods have been adopted official first action.

Comparison of Methods for Determining Sodium in Fertilizers

1981 ◽  
Vol 64 (3) ◽  
pp. 704-708
Author(s):  
Luis F Corominas ◽  
Víctor M Boy ◽  
Pedro Rojas
Keyword(s):  
Phosphate Rock ◽  
Collaborative Study ◽  
Ammonium Oxalate ◽  
Selective Electrode ◽  
Accuracy And Precision ◽  
Flame Emission ◽  
Aoac Method ◽  
Aoac Official ◽  
Aas Method

Abstract The AOAC official first action method, 2.147-2.150, for flame emission spectrophotometry (FES) determination of sodium in fertilizers was compared with the atomic absorption spectrophotometric (AAS) method and the sodium selective electrode (SSE) method. Ammonium oxalate, which was previously compared with water, H2SO4, HC1, and HNO3, was used to extract the sample for all 3 methods. Three synthetic NPK samples, 3 commercial samples (urea, normal superphosphate, and neutrophos), 1 phosphate rock, and 2 Magruder check samples were used for the study. Statistically significant differences were obtained in averages for most of the samples, but few differences were found in standard deviations. The AAS method showed the best accuracy and precision. Accuracy of the AOAC method is acceptable. The SSE method showed the highest deviations from the theoretical values. A collaborative study is recommended to compare the AOAC with the AAS method.

An experimental investigation of fluid flow resulting from the impact of a water drop with an unyielding dry surface

1981 ◽  
Vol 373 (1755) ◽  
pp. 419-441 ◽  
Keyword(s):  
Water Drop ◽  
Roughness Parameter ◽  
Fluid Velocities ◽  
Spatial Dimensions ◽  
Water Drops ◽  
The Moment ◽  
High Degree ◽  
First Contact ◽  
The Impact

The flow of fluid associated with the impact of water drops of radius R at a speed V onto unyielding dry metal surfaces of known roughness R a is described. Spatial dimensions of the deforming drop are normalized by transformations of the kind x ' — x/R , and time scales are normalized according to t ' = tV/R , to permit comparison of events where or differ. It is shown that the primary influence of the surface roughness parameter R a is the determination of the condition for the ejection of secondary droplets by the excitation of an instability in the developing watersheet; provided R a ≪ R , it is possible to evaluate the condition to a high degree of accuracy, and for R a = 0.84 μm it is found to be α4/3 RV 1.69 > 7.4, where α is the eccentricity of the drop at the moment of impact. Deceleration of the drop apex does not commence until > 0.6, contrary to the prediction of Engel (1955) but in good agreement with that of Savic & Boult (1957). Close examination of the very early stages of impact suggests strongly that the so-called watersheet originates at a moment t ' — 0.01 after first contact, regardless of the absolute values of R, V or R a ; the initial normalized watersheet velocity is of order 5. Where there is ejected material, its normalized velocity at the moment of ejection is of the order of 20 % greater than that of the watersheet substrate. Simple calculations also suggest that initial fluid velocities greater than 10 are required immediately before the initiation of the watersheet ( t '< 0.01). Impacts at speeds considerably greater than the appropriate terminal fall speed in air show no deviations in character from those investigated at much lower speeds. A simple subsidiary experiment also suggests that greater impact velocities are required to produce splashing on inclined targets.

Determination of lead residue levels in raw milk from different regions of Mashhad (north‐east of Iran) by AAS method

2013 ◽  
Vol 43 (4) ◽  
pp. 324-329 ◽  
Author(s):  
Hosein Nikpooyan ◽  
Ali Mohamadi Sani ◽  
Nafise Zavezad
Keyword(s):  
Raw Milk ◽  
North East ◽  
East Of Iran ◽  
Residue Levels ◽  
Aas Method

scholarly journals Carbon Dioxide Snow Cleaning of Paper

2021 ◽  
Author(s):  
Ludmila Maskova ◽  
Jiri Smolik ◽  
Petra Vavrova ◽  
Jitka Neoralova ◽  
Magda Souckova ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Adverse Effects ◽  
High Speed ◽  
Suitable Method ◽  
Cleaning Efficiency ◽  
Dry Cleaning ◽  
Paper Surface

Abstract Cleaning of particles from smooth and rough paper surfaces was investigated using a high-speed CO2 snow jet. The measurements included characterization of the jet properties, determination of the cleaning efficiency, and evaluation of the possible adverse effects. The method was compared with the nitrogen jet cleaning and the dry cleaning by commercial materials. The results showed that the CO2 snow jet is able to effectively remove particles from the paper surface and did not cause any observable degradation. The CO2 snow jet cleaning compared with the mechanical dry cleaning showed similar effectiveness without any adverse effects on the paper surface. It was proved that the CO2 snow technique is a suitable method for cleaning of common types of paper materials.

Sign in / Sign up

Export Citation Format

Share Document