Cleanliness Class Research Articles

The concept of microfiltration of hydraulic oil in rail vehicles

The article presents the issue of microfiltration of hydraulic oil from metallic impurities and water that deteriorate the properties of the oil. Tests carried out on oils have shown that periodic oil replacement in machines or vehicles in accordance with their maintenance documentation ensures that the system is emptied of 95% of impurities from the old oil before pouring the new one. The remaining part, i.e. 5% of impurities, together with the oil remaining on the walls of the pipes or inside other hydraulic devices, will mix with the new oil, reducing its cleanliness class. Periodic replacement of hydraulic oil will not allow for complete cleaning of the system. In extreme cases, poor oil condition may cause disruptions in the operation of the machine with the hydraulic system or its downtime for oil replacement or repair. Filtering the oil in the system while the machine is running will clean the oil from impurities and water, extend the oil's service life, without disabling the hydraulic system. The article includes, among others: The justification for the use of microfiltration of hydraulic oil with portable filtering devices in order to extend the service life of the oil until the next replacement is presented. The main purpose of the article is to present the methodology for testing hydraulic oil in accordance with the requirements of ISO, NAS and SAE in order to assign the oil to a given cleanliness class. Additionally, the results of testing the oil cleanliness class in various periods of operation of the machine with the hydraulic installation on a portable measuring device were presented.

Modeling of Filtration Phenomenon in Hydrostatic Drives

Some users consider modern hydrostatic drives and controls to be unreliable and difficult to maintain. This view is often due to operational problems caused by issues with obtaining and then maintaining the appropriate cleanliness class of the working fluid. Recommendations on the selection of appropriate filtration system elements can be found in the literature, but there is no numerical model that could be helpful in a detailed analysis of the phenomenon. In the article, the authors tried to fill the research gap regarding the lack of a filtration model based on the filtration efficiency coefficient of filter elements used in hydraulic drives and controls. The developed model allows users to determine the influence of selected filtration system parameters on the separation of contaminants by filter elements. The model is intended to help designers and users of hydraulic drives and controls in optimizing the filtration system in order to obtain and then maintain the required cleanliness class of the hydraulic fluid. This paper also includes the results of the sensitivity analysis of selected filtration-system operating parameters in terms of the highest efficiency. In order to verify the developed model, experimental tests were also carried out, with the results presented in this paper. Based on the numerical analyses and experimental studies, recommendations that may be helpful in the selection or development of filtration systems used in hydrostatic drives and controls were developed.

Optical-spectroscopic and isotope-geochemical characteristics of zircons from diamond-bearing placers in Yakutia as indicators of diamond ore bodies

Research subject. Zircon grains from diamond placers of the Molodo and Ebelyakh rivers of the Yakut Arctic. Aim. To study the indicator characteristics of zircon to determine sources of diamonds and ways of their transfer to placers; to analyze optical-spectroscopic and isotope-geochemical parameters of zircon grains, their microelemental, U-Pb, and Lu-Hf isotope composition. Materials and methods. A LA-ICP-MS analysis of the U-Pb isotopic and trace element composition of zircon was carried out using a NexION 300S mass spectrometer with an NWR 213 attachment. An analysis of the Lu-Hf isotope system was carried out using a Neptune Plus mass spectrometer with an NWR 213 attachment, located in a room of cleanliness class 7 ISO at the Geoanalitik Center for Collective Use (IGG Ural Branch of the Russian Academy of Sciences, Ekaterinburg). Raman spectra were obtained using a LabRAM HR800 Evolution confocal spectrometer. CL spectra were obtained using a Jeol JSM6390LV scanning electron microscope equipped with a Horiba H-CLUE iHR500 attachment. Results. The local optical spectroscopic characteristics (Raman spectra and catholuminescence) of zircon grains were established, which made it possible to substantiate the conclusion about their high crystallinity and homogeneity (monochrony), as well as to select international zircon standards with similar characteristics for use in LA-ICP-MS analysis to ensure similar conditions for evaporation of the substance and fractionation parameters of the U and Pb elements. LA-ICPMS data on the microimpurity, U-Pb and Lu-Hf isotopic composition of zircon grains from diamond placers, as well as the dose values of their self-irradiation, are presented. Conclusions. The obtained U-Pb dating contributes to reconstructing a more precise history, character, and sequence of manifestation of kimberlite magmatism, tectonic processes, and migration routes of kimberlite material and diamonds across the Siberian craton, within the Yakut kimberlite province.

EFFICIENCY OF WATER-BASED ELECTROLYSIS DEPENDING ON TECHNOLOGICAL PARAMETERS OF CORROSIVE AND ANODE DISSOLUTION OF ALUMINUM

The paper presents the features of the synthesis of hydrogen released as a result of dissolution of the aluminum alloy AMg. To more fully determine the technological characteristics of hydrogen synthesis, we studied the volumes of hydrogen released in the reactor as a result of dissolution of the aluminum alloy AMg. The mechanism of alloy dissolution is established taking into account the effect of impurities in the alloy on the anodic dissolution process. The conditions for accelerating the anodic dissolution of the AMg alloy in the presence of chlorine ions under the conditions of the “negative differential effect” are determined. The dissolution of the AMg alloy in an alkaline chloride solution has an electrochemical nature, which is based on the electrochemical mechanism of hydrogen reduction with the subsequent process of its diffusion into the gas phase. Chloride ions accelerate the active dissolution of aluminum at current densities of 5 A/dm2 instead of 3 A/dm2 at room temperature and surface roughness of class 3-5 (≈5 μm). The greatest influence on the dissolution rate of the alloy has the concentration of NaOH, the dissolution temperature and the surface cleanliness class. The main technological indicator of the improvement of hydrogen electrosynthesis is the use of anodic depolarization of aluminum, its negative values and, as a consequence, the evolution of hydrogen on both electrodes. The depolarization effect is achieved by dissolving the aluminum alloy instead of the oxygen evolution reaction at the anode. The voltage on the cell is 2 times lower compared to industrial alkaline water electrolysis. This makes it possible to save up to 50% of electricity. The absence of oxygen evolution makes this process safer.

Energy-Optimal Structures of HVAC System for Cleanrooms as a Function of Key Constant Parameters and External Climate

This article presents approximating relations defining energy-optimal structures of the HVAC (Heating, Ventilation, Air Conditioning) system for cleanrooms as a function of key constant parameters and energy-optimal control algorithms for various options of heat recovery and external climates. The annual unit primary energy demand of the HVAC system for thermodynamic air treatment was adopted as the objective function. Research was performed for wide representative variability ranges of key constant parameters: cleanliness class—Cs (ISO5÷ISO8), unit cooling loads—q˙j (100 ÷ 500) W/m2 and percentage of outdoor air—αo (5 ÷ 100)%. HVAC systems are described with vectors x¯ with coordinates defined by constant parameters and decision variables, and the results are presented in the form of approximating functions illustrating zones of energy-optimal structures of the HVAC system x¯* = f (Cs, q˙j, αo). In the optimization procedure, the type of heat recovery as an element of optimal structures of the HVAC system and algorithms of energy-optimal control were defined based on an objective function and simulation models. It was proven that using heat recovery is profitable only for HVAC systems without recirculation and with internal recirculation (savings of 5 ÷ 66%, depending on the type of heat recovery and the climate), while it is not profitable (or generates losses) for HVAC systems with external recirculation or external and internal recirculation at the same time.

Assessment of the microbial status of internal environment objects in second cleanliness class health care facilities

Objective. To assess internal environment objects ofsecond cleanliness class health care facilities according to microbiological standards.Materials and methods. The methods of swabbing, direct seeding, membrane filtration and instrumental aspiration were used for sampling. The microbial status was analyzed by cultural and biochemical methods on nutrient, differential and diagnostic media with species identification using the microbiological analyzer. The phenotypic features were studied in vitro by the standard biochemical and microbiological methods in accordance with the principles of good laboratory practice.Results. The microbiological testing of indoor air and internal environment objects of second cleanliness class health care facilities (dental offices) was done to determine the qualitative and quantitative composition of the microbiota. As a result of the taxonomic identification, it has been found that the most common representatives of the air microbiota are Staphylococcus, Micrococcus and Kocuria bacteria, which are true residents of the human dermis.Conclusion. The obtained data provide material for the study of the phenomenon of the modification of phenotypic properties and its use at the stages of hazard detection and profiling and for the minimization of uncertainty within the concept of microbial risk analysis.

Aspects of the industrial manufacture of concentrates for haemodialysis

The import dependence of the pharmaceutical market of Ukraine on concentrates for hemodialysis determines the relevance of their manufacture. Elaboration of the transfer of drug development to industrial manufacture and, accordingly, the development of industrial technology of liquid acid concentrates for hemodialysis involves scaling the process, organization of production control, establishing critical points of the production and determining cleanliness classes for concentrates and risks, including ecological ones.
 The aim of the work is to develop approaches to the development of technology for industrial manufacture of acid concentrates for hemodialysis, identification of risks in the technological process and quality control, as well as analysis of major ecological risks and development of methods for their reduction.
 The object of the study was the regulatory and technical documentation regarding the requirements for hemodialysis concentrates, characterization of the hazard profile of acid concentrates as a source of pharmaceutical wastes and generalization of the information about them in the manufacture of acid concentrates. We used the results of our own experimental research on the development of concentrates. The system-survey method of research and content analysis were used in the analysis.
 On the basis of researches, it was to work up the approaches to the development of technology of industrial manufacture of acid concentrates. Requirements of various normative and technical documents for water for the manufacture were generalized, classes of cleanliness of industrial premises for the preparation of containers, preparation, filtering, and packing of solutions are offered. The scheme of pharmaceutical wastes of acid concentrates, which are formed during pharmaceutical development, industrial manufacture, and medical administration, is presented. The profile of their unsafety is given. Potential and real ecological risks in the manufacture of acid concentrates for hemodialysis and ways to minimize them are presented. The proposed stages of risk management for pharmaceutical waste during the manufacture of acid concentrates of hemodialysis include: determining the hazard profile of acid concentrates for the environment; identification of risks, as well as replenishment of knowledge about the hazard profile; planning and implementation of risk minimization measures as well as evaluation of the effectiveness of these risk reduction measures. Methods for eliminating the safety of pharmaceutical wastes of acid hemodialysis concentrates (dilution with water or electrolysis to obtain by-products) have been developed.

20世紀初頭の米国におけるathlete's footの成立

20世紀初頭の米国におけるathlete's footの成立

EFFICIENCY OF WATER-BASED ELECTROLYSIS DEPENDING ON TECHNOLOGICAL PARAMETERS OF CORROSIVE AND ANODE DISSOLUTION OF ALUMINUM

The paper presents the features of the synthesis of hydrogen released as a result of dissolution of the aluminum alloy AMg. To more fully determine the technological characteristics of hydrogen synthesis, we studied the volumes of hydrogen released in the reactor as a result of dissolution of the aluminum alloy AMg. The mechanism of alloy dissolution is established taking into account the effect of impurities in the alloy on the anodic dissolution process. The conditions for accelerating the anodic dissolution of the AMg alloy in the presence of chlorine ions under the conditions of the “negative differential effect” are determined. The dissolution of the AMg alloy in an alkaline chloride solution has an electrochemical nature, which is based on the electrochemical mechanism of hydrogen reduction with the subsequent process of its diffusion into the gas phase. Chloride ions accelerate the active dissolution of aluminum at current densities of 5 A/dm2 instead of 3 A/dm2 at room temperature and surface roughness of class 3-5 (≈5 μm). The greatest influence on the dissolution rate of the alloy has the concentration of NaOH, the dissolution temperature and the surface cleanliness class. The main technological indicator of the improvement of hydrogen electrosynthesis is the use of anodic depolarization of aluminum, its negative values and, as a consequence, the evolution of hydrogen on both electrodes. The depolarization effect is achieved by dissolving the aluminum alloy instead of the oxygen evolution reaction at the anode. The voltage on the cell is 2 times lower compared to industrial alkaline water electrolysis. This makes it possible to save up to 50% of electricity. The absence of oxygen evolution makes this process safer.

General particle concentration model and experimental validation for cleanrooms

Numerous research reports have demonstrated that the supply air volumes of cleanrooms areusuallyover-designed to satisfy air cleanliness classes, which may lead to enormous energy waste. In this study, five well-recognised international mathematical models for calculating cleanroom particle concentration were analysed, which are all based on uniform particle distribution in the cleanroom, indoor particle conservation, and mass airflow balance, and an improved and more general model has been established for calculating the minimum air change rates according to the expected air cleanliness class. Following the introduction of non-dimensional concentration correction factors, based on the least-squares method, the average relative error between the model-predicted and measured particle concentration is approximately 13.5%. Based on the improved model with correction factor, the test results demonstrate that the particle concentration depends mainly on the air change rate, particle emission rate and return airflow patterns, among others. When the air change rate per hour and ratio of particle concentrations between the return airflow and room average were varied from 40 h−1 to 120 h−1 and 0.7–1.3, respectively, the concentration consequently decreased by approximately 65% and 46%. The particle deposition caused by gravity can be neglected for small particles.

Change in environmental water quality of Neman and Viliya rivers under the influence of city wastewater

The analysis of the biotic component in determining of the quality of surface water is becoming increasingly important. The aim of the work was to assess the ecological quality of the river ecosystems from the influence of wastewater discharges of the Grodno, Stolbtsy and Vileyka cities on the Neman and Viliya rivers based on the macrozoobenthos community.The rare and protected species of hydrobionts from number of European countries live in the studied rivers. Among them are mollusks, coleoptera, caddis flies, and crustaceans. The stoneflies – highest priority indicator group of hydrobionts is missing in the Neman river. Mayflies and caddis flies are also poorly represented (2nd and 3rd indicator groups). The all three main indicator groups of aquatic organisms are presented in the Viliya river. The biotic indices are determined and the class of water purity of the studied rivers was calculated. In accordance with the EU Water Framework Directive, the cleanliness class has good and high value. It is concluded that the negative impact of wastewater from the cities of Grodno, Stolbtsy and Vileyka is of very local importance and weakly affects the biota and ecological quality of the water of the Neman and Viliya rivers.

Classification of Indoor Environment 2018 and Updated Criteria of RTS Environmental Classification

The Finnish Society of Indoor Air Quality and Climate (FiSIAQ) introduced over twenty years ago in 1995 a Classification of Indoor Climate, Construction Cleanliness, and Finishing Materials. After two revised versions, the fourth edition Classification of Indoor Environment was published on May 2018. Based on the criteria set in the classifications, The Building Information Foundation RTS sr started M1-labelling of building products in 1996, named Emission Classification of Building Materials and Cleanliness Classification of Air-handling Components. Indoor air quality and instruments in improving all the sectors to concern are in great importance in Finland. First part of The Classification of Indoor Environment 2018 (CIE 2018) includes new Requirements for Technical Target Values. The other part, Guidance for design and Construction, includes surface structural design, construction site design, Classification of Construction and Construction Work Cleanliness (P1), Classification of Building Materials (M1), Cleanliness Class of Air-handling components (M1) and instructions for designing mechanical systems for buildings. The main changes in the 2018 edition are revised target values for indoor operative temperature, inclusion of a PM2.5 criteria, revision of some acoustical target values and revision of recommended outdoor air flows. Regarding thermal comfort, the target values of the individual indoor climate, S1, will be slightly more demanding than the targets of the S2, good indoor climate, class. The criteria for particulate matter, PM2.5, has been included due to the significant health impact of fine particles. The targets for acoustic environment in offices have been revised to reflect the importance of speech transmission. The recommended outdoor air flows follow the principles of EN15251-2007, considering the common usage of very low-emitting M1-class materials in Finland. The outdoor air flow rates have also been aligned with the recently changed building code values. Companies have developed low-emitting building materials, fixtures, furniture and HVAC-devices during the years to meet the requirements. There are almost 5200 M1-classified low emitting building materials, fixture, furniture and HVAC-devices at the moment (May 2019). The Classification of Indoor Environment 2018 (classes S1, S2) and sub-classifications (P1) and (M1) are integrated part of the new Finnish environmental classification system for building processes called RTS Environmental Classification launched in the spring 2017 and updated in September 2018. The Classification of Indoor Environment has been used in multiple office and residential construction projects during the years. By integrating the CIE 2018 requirements to the RTS 2018, third-party audit and certification of the whole construction project is possible. Therefore, the continuous improvement will be one considerable option.

Experimental studies of the grinding process by planetary grinding head

The object of research is the process of creep feed grinding of parts of aircraft engines with hard-to-machine materials. In the aviation industry from such materials (steel 4Х5МФ1С, ХН53КВМТЮБ, etc.) blades and disks of turbines, segments of nozzle apparatuses, sectors of input guide vanes, plungers, pistons, gears, etc. similar details are made. Blade processing methods are not very effective in creating such parts. Increased wear of technological equipment and tools leads to an increase in temperature in the cutting zone, adversely affects the quality indicators and reduces the life of the product as a whole. Constant sharpening, editing or changing the tool to a new, additional adjustment of the process equipment leads to an increase in the cost of manufacturing parts from difficult-to-work materials. The introduction of creep feed grinding in technological processes allows to avoid the above negative factors. The increase in the technological modes of grinding reduces the processing time, but it becomes a cause of burn in the surface layers and damage to the processed surface. Experimental studies of the process of creep feed grinding are carried out to determine the temperatures in the subsurface layers of the part during its processing and subsequent comparison with the theoretically obtained results of the developed mathematical model. Processing was performed on a surface grinding machine Jotes SPD-30b (Poland). The temperature is measured by the contact method (measuring instrument ОВЕН МВА 8, Russia) and contactless (using a pyrometer СТ 3M, Germany). The results of the experimental temperature values are given in tabular form. According to the research results, it is found that the use of a planetary grinding head for the technology of creep feed grinding of machine-building and aviation parts of difficult-to-process, corrosion-resistant materials leads to a decrease in the power-process parameters. In addition, there is an improvement in the surface cleanliness class (surface roughness Ra is between 1.25-1.8 μm). The results suggest that the technology of creep feed grinding should be introduced into technological processes instead of milling, external pulling and traditional grinding.

Assessment of bowel cleansing quality in colon capsule endoscopy using machine learning: a pilot study.

Background and study aims The aim of this study was to develop a machine learning-based model to classify bowel cleansing quality and to test this model in comparison to a pixel analysis model and assessments by four colon capsule endoscopy (CCE) readers. Methods A pixel analysis and a machine learning-based model with four cleanliness classes (unacceptable, poor, fair and good) were developed to classify CCE videos. Cleansing assessments by four CCE readers in 41 videos from a previous study were compared to the results both models yielded in this pilot study. Results The machine learning-based model classified 47 % of the videos in agreement with the averaged classification by CCE readers, as compared to 32 % by the pixel analysis model. A difference of more than one class was detected in 12 % of the videos by the machine learning-based model and in 32 % by the pixel analysis model, as the latter tended to overestimate cleansing quality. A specific analysis of unacceptable videos found that the pixel analysis model classified almost all of them as fair or good, whereas the machine learning-based model identified five out of 11 videos in agreement with at least one CCE reader as unacceptable. Conclusions The machine learning-based model was superior to the pixel analysis in classifying bowel cleansing quality, due to a higher sensitivity to unacceptable and poor cleansing quality. The machine learning-based model can be further improved by coming to a consensus on how to classify cleanliness of a complete CCE video, by means of an expert panel.

Aplikasi Sistem Pendukung Keputusan Guru Terbaik Berdasarkan Kinerja dengan Metode Analytical Hierarchy Process (AHP)

Abstract— Teacher is professional educator who have the duty, function, and important role in educating the nation. In order for the functions and duties inherent in the functional position of teacher conducted in accordance with the applicable rules, it is necessary to assess the performance of teacher who guarantee a quality learning process. Determine the performance of teacher can encourage an increase in the quality of education and increase motivation and professionalism of teacher in performing the tasks. The headmaster made 15 criteria to determine the best teacher, namely: attendance, discipline rules, responsibility and productivity, social interaction, motivation and self-development, innovative, responsive and initiative, flexibility in other tasks, communication, teamwork, honesty, friendly and polite, aesthetic dress, effective in using the gadget, cleanliness and tidiness class. To determine the performance of the teacher, then one decision that can be done using the Analytical Hierarchy Process (AHP). With the decision making is expected to choose an effective teacher performance. Determination of the teacher's performance is further processed by the criterium Decision Plus (CDP). The results of this study are the order of 4 of the best teachers at Yayasan Lentera Insan.

Studies on Comparison of Particle Concentration Models for Cleanroom

Many independent reports have indicated that cleanroom supply airflow rates are often over-designed to meet the air cleanliness classes, over-supply can cause significant energy waste. It is of great significance to find a more reliable model which can be used to calculate the required air change rate based on a cleanliness class. This paper analyzes 4 well-recognized international particle concentration models for cleanrooms based on uniform distribution of particles, mass airflow balance and indoor particle conservation. This study evaluates the models in perspectives of their assumptions, considered parameters, and application limitations. An improved model is further proposed with examples. The research outcomes can provide a good theoretical support for energy-efficient cleanroom study and design.

Pengaruh Pembelajaran IPS Berbasis Proyek Terhadap Persepsi Konsumsi Berkarakter Mahasiswa S1 Pendidikan IPS Universitas Negeri Malang

This study aims to determine the effect of the project-based learning social studies consumer perceptions of student character. Consumer perception of the character of this research is focused on the consumption of environmentally sound because it was found that the students are less concerned about the environment, especially the cleanliness class. This type of research including quasi experimental, aimed at assessing the effect of an action learning on students' perceptions before and after treatment. Subjects were students of 2015 batch S1 IPS which follows the introductory economics course. The instrument used to measure the consumption of environmentally sound perception using a questionnaire with Likert scale. Based on the homogeneity test the cognitive abilities of students conclusion has a homogeneous character and definitive experimental group and the control is done randomly. This study analyzed SPSS 22.0 for Windows using independent sample T-test. Results of the analysis showed that there were significant differences between the control and experimental class class. Therefore, it can be concluded that the application of project-based learning IPS effect on consumer perceptions of character. In project-based learning allows students trying to construct their own knowledge and actively involved in seeking information so it is expected that students are able to connect theory gained with the existing reality in the environment. Keywords: Project Based Learning, Perception Character consumption http://dx.doi.org/10.17977/um022v1i12016p065

СREATION OF WEAR-RESISTANT LAYERS ON THE NARROW WALLS OF A CONTINUOUS CASTING MOLD WITH ALUMINUM AND CHROME-NICKEL GAS-THERMAL COATINGS

The heat- and wear-resistant layer was created by sputtering aluminum and chromium-nickel coatings to increase service life of continuous casting mold on its narrow sides from M1 copper before the last renovation. Previously, the authors have investigated the structure of the coatings, composition phases, hardness and microhardness of the surface layers. Chrome-nickel thermal spray coating with thickness of 0.5 – 0.6 mm was deposited on the surface of the pair of narrow walls of thick-walled mold. Machining by grinding is necessary to obtain the required cleanliness class of the walls surface, and it is required to increase the thickness of the chrome-nickel coating. When the chrome-nickel coating thickness is more, than 0.8 mm it can be detached. Therefore, to increase the adhesive strength of the chrome-nickel coating with a copper basis the use of aluminum underlayer is considered. As a result, the application of a chrome-nickel coating with aluminum layer can be used to increase the resistance of the narrow walls of a continuous casting mold if there is interaction of the porous layer with α-phase or the porosity reduction of the layer.

Ultra-high Cleanliness of ISO Class Minus 2 Realized by Clean-Unit System Platform for Integrating the Bottom-up and Top-down Systems

The time dependence of the airborne particle count and the cleanliness of an airtight stainless steel clean-unit system platform (S-CUSP) with 100% air feedback through the feedback loop by installing the ultra low penetration air (ULPA) filter just beneath the high efficiency particulate air (HEPA) filter in the feedback loop has been studied. By controlling the number of particles coming out from the HEPA filter, the ultra high cleanliness of ISO class minus 2 has been obtained, which is five orders of magnitude better than that of the super cleanroom (ISO Class 3). Analyses of the experimental results demonstrate that the S-CUSP with flat feedback loop would be a viable economical means to achieve the more stringent cleanliness class, which has the immense importance for expediting the multi-disciplinary experiments and production fields such as nanotechnologies and biotechnologies. DOI: http://dx.doi.org/10.3329/dujs.v61i2.17063 Dhaka Univ. J. Sci. 61(2): 157-160, 2013 (July)

The effects of different disinfectants on polluted surfaces in clean operating room

Objective To compare the effects of ethanol,benzalkonium bromide and chlorine - containing disinfectant on polluted surface in clean operating room.Methods Three rooms of cleanliness class 10 000 were selected.At the end of non - infectious operations,the stuff surfaces which were polluted by blood,body fluids were cleaned firstly by clean water and then wiped by 75％ ethanol,0.5％benzalkonium bromide and chlorine -containing disinfectant respectively..After 30 minutes,samples from the different surfaces were collected,and the clones of bacteria were examined,and the effects of the disinfection were compared.Results There was no significant difference among the three disinfectants ( P ＞ 0.05).Conclusions Ethanol,benzalkonium bromide and chlorine - containing disinfectant can all achieve satisfactory disinfection results on the surfaces in clean operating room. Key words: Disinfectants; Clean operating room; Effect of disinfection