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This article presents paraffin oil mist penetration tests of commercially available air-purifying respirators of different construction conducted using the method described by Standard No. ISO 16900-3:2012, which incorporates flow rates (up to 255 l/min) of test aerosol. The testing method reflects differences in work intensity during the use of respirators. Moreover, the experimental stand, designed according to the international specifications, is described. The results show that the higher the paraffin oil mist flow rate, the higher the penetration index, irrespective of the testing method used and the type of respirator investigated. While at high flow rates, filtering half masks of the first protection class (FFP1) met the requirements of their protection class according to European Standard No. EN 149:20001+A1:2009, filtering half masks of the second and the third protection class (FFP2 and FFP3) did not.

The present paper highlights investigation on hard turning of high strength EN24 steel using multilayer coated carbide insert (TiN/TiCN/Al2O3/ZrCN) under minimum quantity lubrication environment for surface roughness. Measured surface values are found to be less than 1 µm which is much below the surface roughness criteria of 1.6 µm. It indicates that quality components can be obtained during MQL assisted machining of high strength EN 24 steel. This indicates proper cooling and lubrication of machining zone occurred due to application of pressurized oil mist. Developed regression model has been found to be significant because determination coefficient i.e. R2 close to unity (0.9) and p-value is less than 0.05 at 95% confidence level. Hence, environmental friendly minimum quantity lubrication machining can be effectively utilized for production of quality components in industrial shop floors for ecological and economical benefits.

Two-stage electrostatic precipitators are widely used in oil particle purification in industrial workshops, kitchens and ship cabins. As described in this paper, a two-stage electrostatic module was designed, and the effects of seven parameters on the efficiency of collecting oil mist particles with different particle sizes were studied experimentally. On the basis of these experimental results, a semi-empirical efficiency model was developed, and the measured efficiency and calculated efficiency of the present model and the Deutsch model were compared. The comparison results show that the proposed semi-empirical model can well predict the fractional efficiency of the two-stage ESP, whereas the Deutsch model is clearly not applicable in this case. In addition, the degree of influence of seven parameters on the two-stage ESP collection efficiency was studied by using the single-factor sensitivity analysis method with the experimental data. The results show that the degree of influence of various parameters on the particle collection efficiency of 0.31 μm, from high to low, is as follows: the voltage applied to the precharger, the heteropolar distance of the precharger, velocity, the heteropolar distance of the collector, the voltage applied to the collector, the length of the collector plate, and the length of the precharger grounding plate.

The disadvantages of minimum quantity lubrication (MQL) are its poor cooling capability and environment and health hazard as a result of mist formation, resulting in considerable limitations on its widespread application. There is an urgent need to improve its cooling/lubrication performance and environmental performance. Electrostatic atomization is a method where the liquid is electrostatic charged and broken into fine charged droplets by means of electrical forces. This paper investigated the role of electrostatic atomization lubrication (EAL) and nanofluid electrostatic atomization lubrication (NFEAL) on tool wear in end milling of Ti-6AI-4V alloy, and evaluated their environmental performance in non-machining experiments in terms of oil mist concentrations of PM10 and PM2.5. For this research, electrostatic atomization milling system was designed and fabricated. A comparison with the results obtained under MQL condition is also provided. The experimental results show that there was a considerable reduction in tool wear and oil mist concentration for EAL and NFEAL as compared with MQL condition. Furthermore, NFEAL was more effective than EAL for reducing tool wear. But NFEAL yielded slightly higher oil mist concentration than EAL. Therefore, EAL and NFEAL seem to be potential cooling/lubricating approaches for the machining substituting MQL from view point of machining performance, health, and environment.

This study performed a root cause analysis on large fire accident that took place at Severance Hospital in Shinchon, Seoul, where it held around 1,200 inpatients to provide ways of improving fire safety and decrease the risks. Accident reports, comprehensive analysis countermeasure report, and fire safety regulations were used to collect information and data for the root cause analysis. The fire and safety supervisors were also interviewed. The drill down analysis confirmed lack of safety management on kitchen facilities (brazier), chelation of the ventillation duct due to the oil mist, and the problem with allowing the use of gas brazier inside the breakrooms of the hospital. Safety improvements must be taken into an initiative in not only the areas of accident, but everywhere to decrease the risk of danger.

A green manufacturing technology named “electrostatic minimum quantity lubrication (EMQL)” with water-based Al2O3 nanoparticle fluids as cutting fluids was developed in order to improve the cutting property and minimize oil mist concentration during the machining process. The capillary penetration mechanism, oil mist concentration, and heat transfer property of Al2O3 fluid EMQL were investigated. The cutting performance of Al2O3 fluid EMQL and traditional minimum quantity lubrication (MQL) was compared. The results showed that EMQL could improve the penetrability and heat transfer capacity of the lubricant effectively. Compared with Al2O3 fluid MQL and oil-based MQL, Al2O3 fluid EMQL reduced oil mist concentration and cutting temperature remarkably and showed similar cutting performances compared with the oil-based MQL. The excellent performance of this water-based Al2O3 fluid EMQL technology was mainly due to that EMQL could promote a further penetration of the charged Al2O3 nanofluid droplets into the cutting region, which thus reduced the friction force, and the tool durability was maintained obviously and finally presented better machining performance.

The operating conditions of oil mist filters along with the filter media properties are the decisive factors for the evolution of separation efficiency and pressure drop during filter operation. Experimental studies were carried out to determine the evolution of clean gas concentration of oil mist filters with different media properties with regard to the oil transport mechanisms and its dependence on the operating conditions of the filters. The experiments were carried out using two types of glass fiber filter media, one oleophilic and one oleophobic. The effects of filter face velocity and oil loading rate were investigated for both filter media. The effect of media thickness was explored by varying the number of layers. It was found that filter overall separation efficiency can be correlated with the oil transport mechanisms analogously to the correlation to pressure drop proposed by the Film–and-Channel model by Kampa et al. (2004). Decreasing velocities led to a stronger increase in overall penetration when liquid channels are formed in both types of media, which can be attributed to a loss of efficiency for droplets smaller than the MPPS in the size range of 0.1 µm and below, while increasing the oil loading rate had the same effect, however not as distinct. Increasing filter thickness by adding filter layers also caused a stronger increase of penetration during this channel section. The formation of an oil film caused a drop in penetration. The effect of the oil film on penetration was found to be independent of loading rate, but not of velocity, due to its significance for inertial deposition. For highly efficient oleophilic filters, entrainment was found to be the dominant factor for clean gas concentration in steady state.

Oil mist leakage is quite dangerous to the health of the staff as well as for the safe functioning of hydro generators. In this study, a model was established based on flow theory analysis. Three-d...

In this study, a thermo-mechanical model of machining of Ti6Al4V using different oil-mist combination is developed to predict the tool and workpiece temperature at different cutting speed. Machining of chemically reactive materials like Ti6Al4V causes high localization of heat, which contribute to the high tool wear or even premature failure of the tool. The thermal gradient effect is dominating in machining under dry conditions because of its low thermal conductivity. This induces thermal stresses and microstructural changes in the workpiece, thus damaging the workpiece surface integrity. The objective of present work is to understand the effect of different oil mist cooling mixtures at the tool-chip interface and to evaluate the tool and workpiece temperature. Experiments were performed using various mist conditions for different cutting parameters and its effect on the temperature has been studied. Temperature measurement was carried out using a thermal imaging camera. A 2-D finite element thermo-mechanical model is developed using ABAQUS TM to predict the tool and workpiece temperature. Provision of mist cooling has shown a large reduction in the tool and workpiece temperature. It was observed that at low cutting speeds, lubrication characteristics of mist is predominant while at higher cutting speed lubrication suffers.

As a typical representative of green lubrication/cooling mode, minimum quantity lubrication (MQL) is widely recognized by the industry for its excellent machining performance. However, the oil mist generated from oil-based MQL machining process has a direct impact on the ambient air quantity and then does harm those who permanently work in this environment. To alleviate this defect, a novel lubrication strategy named magnetic minimum quantity lubrication (mMQL) allocated with water-based Fe3O4 nanofluid as cutting fluid was proposed. The effect of different magnetic induction on the kinetic viscosity and atomization performance of water-based Fe3O4 nanofluid was investigated. The deposition property of water-based Fe3O4 nanofluid droplets produced by mMQL and LB-2000 vegetable oil droplets produced by MQL were compared, and the corresponding oil mist concentrations (PM10, PM2.5) were also measured. Eventually, the machining performances of water-based Fe3O4 nanofluid mMQL and LB-2000 vegetable oil MQL applied in milling of 430 stainless steel were compared. Results exhibited that water-based Fe3O4 nanofluid presented higher kinetic viscosity and larger droplet size under higher magnetic induction intensity. Water-based Fe3O4 nanofluid mMQL with magnetic induction intensity of 60–100 mT displayed lower PM10 and PM2.5 concentrations, tool flank wear value, milling force, and surface roughness value in comparison with LB-2000 vegetable oil applied in MQL. This water-based Fe3O4 nanofluid used in mMQL showed higher kinetic viscosity and atomized larger droplet-size and thus presented further deposition quantity, which demonstrated alternative cutting performance and lessened the oil mist particles floating in the operating environment.

Introduction: Once a submarine dives, the captive atmosphere inside keeps changing due to release of various pollutant gases. The gases are produced by machinery, cooking, human, paints, batteries, cooking etc. The study was envisaged to measure these gaseous pollutants on surface and in prolonged dive onboard EKM and SSK class submarines. Methods and Material: Detector tubes and pumps were used to measure the concentration of twenty gaseous pollutants in harbour on surface & during sailing in dived condition. In harbour, readings were taken early morning and before secure in the evening. During sailing readings were taken on surface, just after diving and thereafter every four hrs. The readings were recorded in excel sheet and correlated with activities on board at time of taking reading. Results: Only Ammonia and Hydrogen Sulphide were detected at the beginning of the day in harbour, however by the end of the day all other gases were detected except Mercury, Oil mist, Nitrogen Dioxide, Ozone & Arsine. At Sea none of the gases were detected at the beginning of sailing. At 12h post dive all gases were detected except Mercury, Oil mist, Nitrogen Dioxide, Ozone, Halogenated Hydrocarbons & Arsine. Recommendations and Conclusion: The gas concentration values obtained by using detector tubes and pumps were found to be within recommended Permitted Exposure Levels (PEL) for human for continuous exposure. No gas was found to be above the recommended PEL. There was no significant difference in the gas concentration levels in the EKM & SSK Class submarines. Pump and detector tube is a convenient, reasonably accurate and efficient method to measure gaseous pollutants on board Submarines.

A quick rise in the improvement of some radical high performance application materials has been witnessed in last decade poses substantial contest in machining. Many strategic processes have been concocted, where green machining practices have been agreed foremost stress and minimum quantity lubrication (MQL) technique or oil mist lubrication (OML) technique is one of them. In latest spell, oil mist lubrication system has been advanced for serving the machining process more capably in the manufacturing industries but cost comes as a snag for its widespread area of use. To tackle this problematic situation, the present study contracts with the fabrication of a portable OML system which can contest the class and efficacy of machining of the existing OML system. To check the quality of the fabricated setup, turning of Nickel-Chromoly Steel (AISI 4340) with different machining backgrounds has been done. The effect of addition of around 1 µm size Aluminium oxide (Al2O3) and Carbon nanotubes (CNT) powder has been probed during turning with the help Taguchi-based design of experiment. A super hybrid optimization technique, i.e., Taguchi coupled WASPAS with Genetic Algorithm, Simulated Annealing and Particle Swarm Optimization has been used to determine optimal cutting condition. The study, therefore, not only shows the efficiency of the fabricated OML setup but also shows that by using CNT as lubricant, the output responses are very minimum as per the requirement in comparison to other lubricants while machining AISI 4340 steel. This study also shows the use of multiple meta-heuristic optimization shows more accurate result as compared to statistical approach.

Similar to fine dust, liquid aerosols represent a risk to human health since small droplets may enter the respiratory system and cause health problems or severe diseases, such as COVID-19. Oil mist emissions from production processes and from air brakes are reduced by filters and by air dryer cartridges, respectively, while virus-like aerosols are removed by face-masks. Since the two-phase flow processes involved are highly complex and occur on vastly different scales ranging from the scale of single droplets and fibers up to the scale of a whole filter or face mask, the modeling and simulation is extremely challenging. In this work, we present a macro-scale approach for modeling and simulation of the two-phase flow processes in fibrous filters which allows predicting both pressure loss and filtration efficiency from new to steady-state where material parameters and constitutive relationships are obtained based on nano CT scans and micro-scale simulations. Compared to previous work, this approach starts from a physical basis as it relies on mass and momentum conservation and is then closed by material laws. Using this macro-scale approach it is found that both pressure loss and oil mass at steady-state are in good agreement with experimental findings.

Oil mist emitted during cooking is one of the major sources of atmospheric particulate matter in urban areas. A conventional electrostatic precipitator (ESP) is used in some large restaurants; it requires regular electrode cleaning to maintain particle collection performance. However, oil mist generated during cooking is viscous and difficult to clean with water. Herein, we introduce a methodology and a device for cleaning collected oil mist using surface dielectric barrier discharge (surface-DBD) plasma. Our device uses corona discharge for the collection of oil mist. Subsequently, the oil mist collected is decomposed to gas-phase species by surface-DBD plasma. A maximum collection efficiency of 93.25% (for 230 nm di-ethyl hexyl sebacate (DEHS) particle) is obtained at a flow velocity of 1.5 m/s. The maximum oil mist decomposition efficiency is 96.4%. More than 80% of the decomposed oil mist is converted to CO2 and CO under all test conditions. Some of the byproducts other than CO and CO2 are released as particles. Higher frequency results in higher oil mist decomposition efficiency, but also higher byproduct formation of particles. The mechanism of oil mist decomposition by surface-DBD plasma is discussed using optical emission spectroscopy data.

The electrostatic precipitator, one of the air pollution control devices, is widely applied in industrial fields due to the low differential pressure and high particle removal efficiency. However, the electrostatic precipitator use high voltage leading to the risk of unstable sparks and corrosion. As a solution to this challenge, two-stage electrostatic precipitators that separates the pre-charging and collection stages have been developed, but expensive anticorrosive metals are required. In this study, we developed a carbon based non-metal two stage electrostatic precipitator to investigate the particle removal performance for oil mist. Five types of collection modules were manufactured by varying the materials of the high voltage and ground electrodes, and the particle removal performance depending on the flow velocity, particle diameter, and applied voltage was evaluated for each collection module. For the present experiment, there was no significant difference in particle removal performance regardless of electrode material. We confirmed the average electric field strength for each electrode material through numerical analysis. As a result, the non-metal electrode also showed an electric field strength similar to that of the metal electrode. The experimental results corresponded to the electrostatic precipitation theory, the Deutsch equation and Cochet's theory, and showed the maximum removal efficiency of PM2.5 at 91.5% at 3 m/s, the fastest flow rate in this experiment. Carbon is lighter, cheaper, and more anticorrosive than general metals. Therefore, the characteristics of the carbon based non-metal electrostatic precipitator introduced in this study are expected to be applied to industrial post-treatment facilities.

Oil mist detector is an important equipment in the early stage of the explosion of the crankcase for marine engine, and the oil mist detection module determines the working performance of the oil mist detector. By means of infrared light transmission principle, method and compositions of the detection module was extracted. Through analyzing the safety and reliability of hardware circuit module, real-time and accuracy of detector, overall scheme design of oil mist detection module was carried out. By analysis of principle and detection method oil mist, power and photoelectric conversion modules were designed and developed. Finally, laboratory verification of oil mist detection module was conducted, experimental results showed the module satisfied the design and function requirements.

Metalworking fluids used in industrial workshops may present a major threat to the health of workers who have been exposed to a high oil mist concentration over a long period of time. Therefore, monitoring the temporal and spatial distribution of particulate matter concentration has great practical significance for the control of oil mist. Traditional particle monitors are generally cumbersome, expensive, and difficult to maintain, which to some extent restricts their extensive use in workshops. Recent years have witnessed tremendous developments in the area of low-cost sensors, which are of great help in obtaining high-density pollution data. In this paper, we evaluate the performance of an inexpensive laser sensor (A4-CG) during long-term oil mist monitoring in a machine shop for the first time. With the use of Lora technology, we developed an online oil mist monitoring network to access real-time concentration, temperature, and humidity information from distributed monitors. According to the results, the sensor data correlated well with measurements by the reference instrument (R2 = 0.96), which means that the distributed sensor network can accurately detect the concentration level of oil mist in the workshop. In fact, most of the sensors demonstrated stable operation for up to half a year according to cluster analysis, while several sensors exhibited serious data drift. Furthermore, the results indicate that the peak oil mist concentration in most areas during production exceeded the value of 0.5 mg m-3 recommended by NIOSH, and it was found that appropriately lowering the relative humidity can make sampling more accurate, while lowering the temperature can reduce the oil mist concentration in the workshop. Thus, measures to control oil mist such as generation and distribution of pollution sources should be on the agenda.

Failures on machine tools not only occur on main components, but also on auxiliaries like cooling units or oil mist separators, which causes productivity losses similar to failures on main machine components. Due to their separation from the machine’s control network, their health status is in most cases not monitored. In this study, a new approach for online condition monitoring of auxiliary units by the example of an oil mist separator connected to a 5-axis machine tool is presented. The data is analyzed via machine learning principles in order to deduct an adequate condition assessment, encompassing environmental influences., Procedia CIRP, 88, ISSN:2212-8271, 13th CIRP Conference on Intelligent Computation in Manufacturing Engineering

The oil-based cooling media is one source of pollution and made from non-renewable resources. The use of cooling in machining with a mist cooling system will reduce the amount of oil consumption in for cooling media, decreasing of oil make the amount of pollutant decrease but still produce pollutant event in small quantity. Replacing oil with palm oil will remove pollutants caused by the use of oil as a cooling media in the machining process.This study sets out to reveal the surface roughness of St 60 steel machined by milling process using different spindle speeds (360, 490, and 720 rpm) and mist cooling pressures (0.5; 1.5; and 2.5 bars). The milling process carried out using up milling with the feed rate of 75 mm/min. The surface roughness was tested using surface roughness tester at 3 different points to obtain the average arithmetical surface roughness value (Ra). The results showed that the enhancement of surface roughness occurred along with the increase of mist cooling pressure, however, it dropped when the pressure reached the value of 2.5 bars. On the other hand, the higher spindle speed applied could reduce surface roughness. These phenomena can be explained due to the less optimum of the spraying process on cutting region when the pressure below 2.5 bars was used. Yet, along with the further addition of pressure, the spraying occurred on the cutting region turned to be more effective due to the better ability of oil mist to penetrate the narrower cutting crevice. The highest average Ra value has resulted in the spindle speed of 360 rpm and the mist cooling pressure of 1.5 bars with the Ra of 2.65 µm. Conversely, the lowest one can be observed on sample cut using the spindle speed of 720 rpm and mist cooling pressure of 2.5 bars with a value of 1.29 µm.

Oil is important to compressors, but it brings some side effects on the performance of refrigeration systems. Discharge valve or orifice in the compressor plenum is the gateway for the oil to leave the compressor and circulate in the system. The space of the compressor plenum has the potential to separate the oil mist from the refrigerant so that oil circulation ratio (OCR) is reduced. In this study, the formation, distribution, and movement of oil droplets in the plenum are investigated through visualization and CFD simulation. Videos of oil atomization are captured by the high-speed camera to describe how oil mist is formed. The distribution of droplet size and velocity is quantified by video processing techniques. Discrete phase model gives the numerical approach to study the oil droplet movement inside the compressor plenum. The numerical simulation is verified by comparing visualization results with simulation results. The oil flow phenomenon and its quantification provide important information for the design of separation structure incorporated in the compressor. Also, a set of tools are developed and verified to study the oil droplets behavior in different types of compressor plenums.

Building on work by Kampa et al. (2014) about the liquid distribution in multi-layer oil mist filters, a mesoscale empirical model is proposed for their efficiency. It decomposes the total penetration into a product of independent ‘building blocks’ that are aligned with the mesoscale liquid distribution in steady state, essentially in the form of an oil film and a channel region. The film (typically one very thin region per sandwich) is associated with a film penetration Pfilm and the channel region (consisting typically of multiple layers) with a channel penetration Pchannel. The first layer of wettable media also represents a separate contribution P1st layer. A method is described to derive these unit penetrations from a set of measurements. Experiments are then carried out with filters composed of conventional glass microfiber media, both wettable and non-wettable to compressor oil, in which the fractional penetration of the entire sandwich was measured by SMPS between about 30 and 700 nm. It is shown that the film penetration is substantially reduced for particles above about 100 nm in comparison to that of the dry media due to enhanced inertial deposition, while the channel penetration is generally higher across the board, probably because of a loss of active fiber in the partially saturated media. The last part of the paper is dedicated to practical consequences of this efficiency model. It is shown that the fractional efficiency for an arbitrary number of (identical) layers can be predicted quite accurately from the unit penetrations. Additional measurements of the total downstream concentration as a function of time are used to discuss and explain changes from start-up until steady state.

A novel imaging sensor which is made of image optical-fiber bundle and industrial camera is proposed. All of the image optical fiber component are custom made and the diameters of the mono fibers are only 1 or 2 μm. In order to match the resolution of image optical-fiber bundle, the pixel size of the sensor chip are also smaller than 2 μm. After removing the protective glass window that cover the sensor chip of camera, the high-resolution imaging can be realized by bonding the optical fiber component and the sensor. The theoretical analysis and experimental result show that the resolution of the sensor is larger than 250 lp/mm, which can improve the imaging quality of industrial detection and monitoring. In particular, the proposed imaging sensor is suited for the oil mist or dust detection environment.

To improve machining performance and lower oil mist concentration in machining workshops, a near-dry machining technique called "electrostatic minimum quantity lubrication (EMQL)" was proposed, in which nano-lubricants using graphene nanoplatelets (GPLs) as additives were employed. The penetrability and deposition property of GPL-oil mists under EMQL condition were investigated. The tribological and machining characteristics of GPL lubricant EMQL were compared with those of an ordinary minimum quantity lubrication (MQL) technology. The results indicated that GPL lubricant EMQL reduced coefficient of friction (COF) and worn scar diameter (WSD), as well as improved machining performance with a lower oil mist concentration compared with GPL lubricant MQL. The superior performance of GPL lubricant EMQL was attributed to the fact that the use of EMQL considerably enhanced the penetration and deposition of GPL-oil droplets to the rubbing interface, which reduced friction and wear significantly, and thus resulted in better tribological and machining performances.

Minimum quantity lubrication (MQL) technique has been widely used in different machining processes. However, oil mist discharged from MQL system induces negative effects for working space. In this paper, a continuous MQL system with ultrasonic vibration (U-CMQL) is proposed for near dry machining process. A valve-less micro-pump is designed to supply continuous lubrication to the cutting edge without making oil mist. Penetration mechanism of micro lubrication in ultrasonically assisted machining (UAM) process is firstly analyzed. Experiments are carried out to study the influence of dry machining, ultrasonically assisted machining, and U-CMQL machining on turning performance of Ti–6Al–4V alloy. Cutting force, tool wear, surface roughness, and chip morphology are experimentally analyzed. The results show that U-CMQL technique not only maintains neat working area but also improves the machinability characteristics to some extent. In comparison with dry machining and ultrasonically assisted machining, U-CMQL shows lower cutting force and tool wear rate due to the combined advantages of lubrication and vibration. Moreover, short tool-chip contact length, favorable chip morphology, and better surface integrity are obtained under U-CMQL machining.

A cost-effective and eco-friendly alternative to conventional flood cooling-lubrication and minimum quantity lubrication (MQL) is electrostatic minimum quantity lubrication (EMQL). EMQL, which is a novel green machining technology that utilizes the synergetic effects between electrostatic spraying (ES) and MQL, has been successfully shown a potential in milling process. However, the effective application of EMQL is not only connected with machining parameters, such as cutting speed and feed rate, but also related to oil mist parameters including charging voltage, lubricant flow rate, air pressure, and nozzle position and distance. This paper investigated the effect of the above parameters on the cutting performance of EMQL turning stainless steels in comparison with completely dry and conventional wet and MQL cutting. The results suggested that cutting speed and voltage were important factors affecting the effectiveness of EMQL, and found that there were the optimum air pressure and nozzle position and distance when EMQL turning AISI 304 stainless steel. Properly selecting these parameters, a viable alternative to wet and MQL cutting could be achieved by promoting lubricants into cutting interface to reduce friction and adhesion of work-piece materials on the interface.

In industrial units, EFD maps are used as suitable methods for optimal management and controlling the release of pollutants into the environment. Hence, the main objective of the present research was to obtain the Environmental Flow Diagram-Air Pollutants (EFD-AP) map of the Purified Terephthalic Acid Production Units (PTA) of petrochemical industries. To this end, the flow of materials, feed, and productions of a PTA production unit in the southwest of Iran was analyzed. The pollutants of all 7 process sources and 2 combustion sources were sampled and measured using standard procedures. Finally, according to the results some calculations were done to determine the APs emission factors of the sources, and the EFD-AP maps of the studied unit were prepared. Results showed that the total emission factors of the Acetic acid, Methyl acetate, PTA powder, oil mist, CO, NO, NOx, CxHy, Co, Mg, Cu, Ni, Cd, Ti, Mo, Cr, and Pb were 219.518, 1.912, 44.58, 0.888, 64201.211, 1982.094, 2091.858, 23082, 76.868, 0.0193, 15.102, 36.829, 2.914, 37.623, 15.367, 200.572, and 2.888 mg per tonne of PTA, respectively. Also, results revealed that process sources emit different toxic and criteria pollutants into ambient air, while combustion emission sources (S8: hot oil furnace, S9; incinerator) have the main role in releasing criteria air pollutants, toxic trace elements and GHGs. It should be noted that emission factor of GHGs (CO2) for selected PTA unit was equal to 54661355 mg per ton of PTA production. Therefore, EFD-AP maps used for prioritization, controlling and management of APs emissions. Moreover, these maps have main role for preparing industrial atmospheric emission control action plan.

Ti6Al4V, which is one of difficult-to-cut metals, is widely used in an aircraft structure, parts of a gas turbine and medical equipment, and a hole making operation of Ti6Al4V is needed to fasten the parts. When a high speed drilling by a conventional twist drill is applied to hole making of Ti6Al4V, it is very difficult to obtain highly accurate hole in diameter, roundness and inlet - outlet edge quality due to a rise of cutting temperature caused by a small heat conductivity. Incidentally, it is well-known that Ti6Al4V transiently causes phase transformation from α phase (close-packed hexagonal lattice) to β phase (body-centered cubic lattice) as soon as it reaches the transformation temperature of 883 ℃ (1621 F). One of the authors newly developed a hole making machine to enable orbital drilling based on Double Eccentric Mechanism, in which an endmill driven by a built-in AC motor can rotate clockwise on its own axis at high speed and simultaneously can revolve counter-clockwise on eccentric axis at low speed [1]. In dry cut orbital drilling tests of Ti6Al4V by the machine, it was ascertained that a hole diameter decreased from 15.02 mm at the first hole to 14.43 mm at the 40th hole although wear of endmill was maintained to be tiny value. However, by supplying oil mist from oil hole in the endmill the hole diameter was almost constant from 15.00 mm at the first hole to 14.96 mm at the 40th hole [2]. Based on the fact ascertained by temper color of Ti6Al4V’s chip that the temperature of Ti6Al4V being machined exceeded the transformation temperature of 883 ℃ (1621 F) after the 16th hole drilling, this paper discloses that the phase transformation from α phase to β phase may be a prime cause of the decrease in hole diameter by applying an image data processing to microstructures obtained optically from the specimen of Ti6Al4V around the inner surface of hole.

Oil mist particles emitted in industrial buildings are harmful to health. To evaluate the control effect of existing ventilation strategies on oil mist particles, this work conducts field investigations on the processing workshops of different scales and processes. Through on-site measurements, the basic characteristics of the mass concentration, quantity concentration, particle size distribution, processing technology, and emission rate of oil mist particles can be learned from different angles. The article presents the concept of unit emission rate index, which can provide reference data for ventilation design, as well as input parameters for simulation calculation. At the same time, based on the air change rate, the effect of controlling oil mist particles was evaluated, and the relationship between the air change rate and the concentration of the workshop was investigated. In view of the uniformity of the oil mist concentration in the workshop, the influence of the process emission rate and the ventilation mode on the mass concentration of oil mist particles was discussed. The conclusions obtained can be used as data support for optimizing ventilation strategies to control oil mist pollution and play a certain guiding role in the ventilation design and evaluation of industrial buildings.

Developing robust superhydrophobic surfaces integrating flame retardancy and multitasking oil separation performance is important but challenging for the restoration of environmental pollution caused by the discharge of mixtures containing oils. Herein, a kind of high-efficiency and flame-retardant superhydrophobic ceramic fiber felt (SCFF) is facilely prepared by chemical vapor modification (CVD) to realize efficiently oil/water mixture separation and oil mist interception. Through the CVD of ceramic fiber with tetrachlorosilane and trimethylchlorosilane, methyl terminated silicon-oxide compound is grafted on the surface of the material, which instantly transfers it from hydrophilic to superhydrophobic in 1 min. The modified surfaces are highly water repellent (water contact angle above 156°) that keep stable in various organic solvents and under high temperature (260 ℃) treatments even after burning. The result of oil/water mixture separation shows that the SCFF has excellent separation efficiency (98.78%) and high oil flux (35,939 L·m−2·h−1), which remain stable after 10 repeated cycles. In the oil mist environment, the double-layer SCFF can intercept 96.04% of oil droplets from the airflow. Further, the mechanism of oil leaking and intercepting is illustrated. These features make the SCFF promising for the remediation of oil spills and high-temperature oil mist interception.

To analyze the cause and mechanism of oil mist escaping from the lower guide bearing during the operation of a turbine, the oil-gas mixture in the lower guide bearing was numerically simulated by using the VOF two-phase flow model and the SST turbulence model. The influences of different sealing clearances and speeds on the flow field and the oil-gas distribution in the oil tank were studied, and the escaping characteristics of oil mist were analyzed. The results show that increasing the clearance of the labyrinth seal will reduce the pressure difference between the inside and outside of the oil tank and reduce the driving force for the escape of the oil mist. However, increasing the clearance will increase the turbulence of the flow field, the number and volume of bubbles in the lubricating oil, which will lead to the uneven distribution of oil and gas and reduce the motion stability of the lower guide bearing. The change of speed will affect the normal use of the shaft-collar pump. High speed will aggravate the generation of bubbles in the oil tank and increase the possibility of cavitation in the lower guide bearing structure. In engineering practices, it is necessary to comprehensively consider factors such as oil mist escape phenomenon, economic benefits, process manufacturing and assembly, and adopt the lower guide bearing structure with a suitable labyrinth seal clearance.