scholarly journals Influence of solid particle contamination on the wear process in water lubricated marine strut bearings with NBR and PTFE bushes

2021 ◽  
Vol 28 (4) ◽  
pp. 167-178
Author(s):  
Ewa Piątkowska
Keyword(s):  
Fresh Water ◽  
Solid Particle ◽  
Geometric Structure ◽  
Optical Microscope ◽  
Contaminated Water ◽  
Butadiene Rubber ◽  
Key Factors ◽  
Wear Process ◽  
Particle Contamination ◽  
Shaft Journal

Abstract This paper reports on a study of the influence of solid particle contamination on the wear process in water-lubricated slide bearings (steel-acrylonitrile-butadiene rubber (NBR) and steel-polytetrafluoroethylene (PTFE)). To compare the wear of the shaft journal and bushes (NBR and PTFE) when lubricated with fresh water and contaminated water, an experiment was carried out to identify key factors that influence the state of wear of slide bearing. The amount of wear was checked by means of geometric structure measurements on the journals, namely, roughness profile measurements using both a contact profilometer and an optical microscope. The obtained results enabled correlations between the material comprising the sliding sleeve, roughness of the journals and contamination inside the water-lubricated slide bearings.

Compatibilising additives for enhancing the interaction at the phase interface in thermoplastic vulcanisates based on rubbers of different polarity and polypropylene*

2018 ◽  
Vol 45 (7) ◽  
pp. 307-310
Author(s):  
O.A. Panfilova ◽  
S.I. Vol’fson ◽  
N.A. Okhotina ◽  
R.K. Sabirov ◽  
I.V. Baranets ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Cooling System ◽  
Phase Interface ◽  
Optical Microscope ◽  
Strength Properties ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Experimental Conditions ◽  
Tensile Elastic Modulus ◽  
Distribution Of Components

The possibilities of increasing the interaction between the components of previously developed thermoplastic vulcanisates based on polypropylene and a combination of isoprene and nitrile butadiene rubbers were studied. The morphology of the composites was recorded by means of optical microscopy using an analytical complex based on a Leica DM-2500 optical microscope, a Leica DFC-420C digital high-resolution colour camera with a Peltier cooling system, and a specialised computer desk. The parameters of crystallisation of polypropylene were measured by differential scanning calorimetry using a DSC 204F1 Phoenix instrument (Netzsch). The physicomechanical properties of the vulcanisates were also determined. Maleinised polypropylene, a copolymer of ethylene with vinyl acetate, and their mixtures were used as compatibilising additives. Maleinised polypropylene was introduced together with polypropylene in a quantity of 1–10 parts; no changes in properties were observed with increase in the dosage above 4 parts, so this dosage was used. The copolymer of ethylene with vinyl acetate (1–10 parts) was introduced into the rubber phase at the stage of rubber mix preparation specially to improve the compatibility of polypropylene and nitrile butadiene rubber. The introduction of maleinised polypropylene leads to an increase in the workability and in the level of elastic strength properties, in particular the tensile elastic modulus and hardness. A considerable increase in the uniformity of distribution of components throughout the volume, a finer dispersion of the rubbers in the polypropylene matrix, and a reduction in the number of pores in the material were shown, and also an increase in the degree of polypropylene crystallinity measured under experimental conditions. The most positive effect is observed with the combined introduction of the copolymer of ethylene with vinyl acetate and the maleinised polypropylene: the nominal stress under elongation increases by 34%, and the elongation at break by 15%. The combined introduction of the compatibilising additives improves the compatibility of the components of the system, the phase boundaries become more diffuse, there is a reduction in the optical density of rubber-rich zones, and these zones are penetrated by polypropylene fibrils.

Rising speed and dissolution rate of a carbon dioxide bubble in slightly contaminated water

1999 ◽  
Vol 378 ◽  
pp. 319-334 ◽  
Author(s):  
F. TAKEMURA ◽  
A. YABE
Keyword(s):  
Carbon Dioxide ◽  
Drag Coefficient ◽  
Dissolution Rate ◽  
Solid Particle ◽  
Sherwood Number ◽  
Ccd Camera ◽  
Numerical Results ◽  
Fluid Sphere ◽  
Contaminated Water ◽  
Cap Model

The rising speed and dissolution rate of a carbon dioxide bubble in slightly contaminated water were investigated experimentally and numerically. We developed an experimental system that uses a charged-coupled device (CCD) camera coupled with a microscope to track the rising bubble. By precisely measuring the bubble size and rising speed, we were able to accurately estimate the drag coefficient and the Sherwood number for the dissolution rate of gas bubbles at Reynolds numbers below 100 in the transient regime, where the bubble changes from behaving as a fluid sphere to behaving as a solid particle. We also numerically estimated the drag coefficient and Sherwood number of the ‘stagnant cap model’ by directly solving the coupled Navier–Stokes and convection–diffusion equations. We compared our experimental results with our numerical results and proposed equations for estimating the drag coefficient and Sherwood number of the bubble affected by contamination and clarified that the gas–liquid interface of the carbon dioxide bubble in water is immobile. We also show that the experimental and numerical results are in good agreement and the stagnant cap model can explain the mechanism of the transient process where the bubble behaviour changes from that of a fluid sphere to that of a solid particle.

Research on the Engagement Effect of Wedge Tooth

2011 ◽  
Vol 130-134 ◽  
pp. 1789-1793
Author(s):  
Xiao Gang Jian ◽  
Hong Sheng Jia ◽  
Yong Ming Bian ◽  
Lai De Shi
Keyword(s):  
Mathematical Model ◽  
Geometric Structure ◽  
Life Prediction ◽  
Optimization Design ◽  
Working Life ◽  
Tooth Surface ◽  
Key Factors ◽  
Working Mechanism ◽  
Tooth Shape ◽  
Steel Strand

In this paper, we analyze the working mechanism of the wedge-type anchorage in the hydraulic synchronizing lifting device and tradition one, discuss the engagement effect between the wedge and the steel strand, establish a mathematical model to analyze the wedge tooth strength and evaluate carrying contaminant capacity qualitatively. The results of the study indicate that: the hardness difference between the wedge and the steel strand, the tooth shape and relevant parameters, the inside tooth surface geometric structure, are key factors to improve the performance of the wedge-type anchorage, which provides the basis to the wedge tooth optimization design and its working life prediction.

Lubrication Mechanism of Solid Lubricants in Oils

1983 ◽  
Vol 105 (2) ◽  
pp. 245-252 ◽  
Author(s):  
T. Hisakado ◽  
T. Tsukizoe ◽  
H. Yoshikawa
Keyword(s):  
Solid Lubricant ◽  
Solid Lubricants ◽  
Optical Microscope ◽  
Wear Process ◽  
Copper Disk ◽  
Lubricant Films ◽  
Oil Flow ◽  
Solid Lubricant Films ◽  
Lubricating Properties ◽  
Worn Surfaces

Lubricating properties of machine oils containing such solid lubricants as (CF)n, MoS2, graphite, etc., were studied on a pin and disk machine by measuring an electric contact resistance and a friction force. After lubrication tests, solid lubricants films and transferred wear particles on worn surfaces have been observed by means of an XMA and an optical microscope. The wear mechanism of metals was analyzed considering a mean peak to peak distance and a mean depth of scratches on worn surfaces. The effects of particle size and concentration of (CF)n, and a suspending agent AD-6 on the friciton and wear process were also discussed. It was found that when the large number of (CF)n particles can penetrate into the interface in accordance with an oil flow, they show a good performance as a lubricant but solid lubricant films were not formed on worn surfaces besides graphite particles embedded on those of a copper disk.

Tribological Properties of Mo/NiCrBSi Thermal Spray Deposits

1998 ◽  
Author(s):  
V. Fervel ◽  
B. Normand ◽  
C. Coddet ◽  
M. Delaet
Keyword(s):  
Cast Iron ◽  
Adhesive Wear ◽  
Tribological Behavior ◽  
Optical Microscope ◽  
Atmospheric Plasma ◽  
Wear Process ◽  
Dry Conditions ◽  
Nicrbsi Coating ◽  
The Difference ◽  
Nicrbsi Coatings

Abstract The tribological behavior of Mo/NiCrBSi coatings obtained by atmospheric plasma spray was studied under dry conditions using an Amsler machine. Discussion is made on the effects of the plasma gas mixture and of the preheating of the substrate. The wear process of Mo/NiCrBSi in situation of dry rolling-sliding contact versus cast iron was observed using a profilometer, an optical microscope, and a scanning electron microscope. It was found that the wear mechanism could be divided into two steps : the first one corresponds to an abrasive wear; it results from the difference in hardness between the counter-specimen and the Mo/NiCrBSi coating. The second one corresponds to an adhesive wear resulting from the transfer of cast iron from the counter-specimen to the coating.

The Behavior of Adhered Fragments Interposed Between Sliding Surfaces and the Formation Process of Wear Particles

1981 ◽  
Vol 103 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Tadashi Sasada ◽  
Susumu Norose ◽  
Hiroshi Mishina
Keyword(s):  
Formation Process ◽  
Optical Microscope ◽  
Wear Particles ◽  
Mixed Structure ◽  
X Ray ◽  
Wear Process ◽  
Sliding Surfaces ◽  
Removal Process ◽  
Transverse Movement

To study the behavior of adhered fragments on rubbing surfaces, the transverse movement of a slider is measured and recorded during the wear process. The gap between the mating surfaces is enlarged gradually through the origin and growth of a transfer particle adhering to the slider and then closed suddenly by the removal of the particle. The removal process of wear particles can be observed by an optical microscope. Furthermore, an X-ray microanalysis is made on the cut section of the rubbing system just before the removal of the particle. The particle is press-slide flattened in shape and has a hair line mixed structure containing metals of both mating surfaces. The maximum lift of the slider is nearly equal to the size of the produced particle. These observations show that the adhered fragments are piling up and are being press-slide flattened between the mating surfaces until their final removal as wear particles.

scholarly journals Effects Of Textile Industrial Waste Water And Uptake Of Nutrients On The Yield Of Rice

1970 ◽  
Vol 36 (2) ◽  
pp. 319-331 ◽  
Author(s):  
RA Begum ◽  
MW Zaman ◽  
ATMAI Mondol ◽  
MS Islam ◽  
MF Hossain
Keyword(s):  
Waste Water ◽  
Fresh Water ◽  
Industrial Waste ◽  
Block Design ◽  
Nutrient Content ◽  
Water Yield ◽  
Contaminated Water ◽  
Industrial Waste Water ◽  
Mixed Water ◽  
Contaminated Field

An experiment was conducted at Mouchack textile industrial area of Gazipur for two consecutive years (1999-2000) to study the effects of use of industrial waste water on the yield, nutrient content, and uptake of Boro rice. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The six treatments in this study were: T1: uncontaminated field + fresh water, T2: uncontaminated field + mixed water, T3: uncontaminated field + contaminated water for non-contaminated field, and T4: effluent contaminated field + fresh water, T5: effluent contaminated field + mixed water, T6: effluent contaminated field + contaminated water for contaminated field. Among the six treatments, uncontaminated field + fresh water (T1) showed the best positive effect on rice. The N, P. K, and S contents and uptake were higher in T1, but Zn, Mn, Fe, Cu, and Pb were higher in T6 treatment. The treatment T1, gave the highest grain yield (5.23 t/ha in 1999 and 5.40 t/ha in 2000), followed by mixed water (4.19 t/ha in 1999 and 4.24 t/ha in 2000) in both the growing seasons. Keywords: Industrial waste water; heavy metal; textile waste water; yield; nutrient content; uptake; rice. DOI: http://dx.doi.org/10.3329/bjar.v36i2.9260 BJAR 2011; 36(2): 319-331

scholarly journals Defining Key Factors in Carbon Black-Filled NR/BR Compounds for Balancing Aircraft Tire Tread Properties

2019 ◽  
Vol 3 (2) ◽  
pp. 47
Author(s):  
Indriasari ◽  
Wisut Kaewsakul ◽  
Wilma K. Dierkes ◽  
Anke Blume
Keyword(s):  
Carbon Black ◽  
Mixing Time ◽  
Resistance Index ◽  
Processing Parameters ◽  
Evaluation Procedure ◽  
Butadiene Rubber ◽  
Rotor Speed ◽  
Key Factors ◽  
The Impact ◽  
Full Factorial

Carbon black (CB) is the most common reinforcing filler used in aircraft tire tread formulations. For CB-reinforced natural rubber/butadiene rubber (NR/BR) compounds, material and processing parameters are important factors that need to be controlled, as they can influence both, processing as well as the vulcanizate properties. It is essential to investigate and optimize the key elements, in order to achieve the target properties, while maintaining an acceptable trade-off for other characteristics. In the present study, the type of BR, mixer temperature, rotor speed, and filler mixing time were selected as input factors. A complete design of experiments (DOE) process was performed that comprised the following—two-level full factorial setup for initial screening, response surface method (RSM) for optimization, and confirmation runs for validation. This evaluation procedure was used to study the impact of factors and their interactions on the properties of CB-filled NR/BR compounds. From the DOE optimization which was later confirmed by the DOE validation, high rotor speed and long filler mixing time were the most significant factors in improving the Mooney viscosity, modulus at 300% elongation, hysteresis (tan delta), as well as in reducing the filler–filler interaction (Payne effect). In the case of tensile strength (TS) and abrasion resistance index (ARI), high rotor speed and long filler mixing time had an adverse effect, thus, causing a deterioration of these properties. Therefore, it is recommended to decrease the filler mixing time when combining it with high rotor speed.

scholarly journals IMPROVING THE TECHNOLOGY OF PRODUCING CELLULOSE OXIDATION-ORGANOSOLVENT WAY OF NON-WOOD PLANT MATERIALS

2019 ◽  
pp. 269-276
Author(s):  
Alesya Valer'yevna Vurasko ◽  
Elena Igorevna Simonova ◽  
Anastasiya Rashitovna Minakova ◽  
Valeriy Pavlovich Sivakov
Keyword(s):  
Acetic Acid ◽  
Fresh Water ◽  
Alkaline Solution ◽  
Raw Materials ◽  
Alkaline Treatment ◽  
Contaminated Water ◽  
Acidic Water ◽  
The Third ◽  
Vegetable Raw Materials ◽  
Washing Water

An improved process flow diagram for the production of cellulose by oxidation-organosolvent method from non-wood vegetable raw materials with pre-alkaline treatment and recovery of the spent cooking solution has been developed. It is shown that it is possible to obtain technical cellulose with the desired properties with repeated use of the spent cooking solution, which allows to reduce the consumption of acetic acid and fresh water by two and 1.7 times, respectively. The scheme includes the following stages: preparation of raw materials; preparation of the cooking composition and alkaline solution, alkaline treatment, cooking and washing of cellulose, recovery of the spent cooking solution, neutralization of the spent alkaline solution and the use of contaminated water.  When implementing the flowcharts are formed by the following types of contaminated water: water for rinsing plant material circulates through the first and second steps of adding water with catalyst; circulating the water from flushing technical pulp in three stages – the washing water from the first washing stage is directed to the Converter; the washing water from the second stage washing sent to the first stage of the wash technical cellulose; the third step of the rinsing water is fed from the drum filter with the addition of fresh water; the concentration of sodium hydroxide in the spent alkaline solution is 1.75 %. In the neutralizer, weakly acidic water with a concentration of acetic acid of 0.83% and sodium acetate with a concentration of 2.5% is formed; weakly acidic water from the neutralizer is fed to the first stage of washing plant raw materials. Fresh water is used for the preparation of balanced peracetic acid, alkaline solution and the third stage of technical cellulose washing. Solid waste is formed in the hydraulic separator during washing of vegetable raw materials; in the tank of the spent cooking solution in the form of a precipitate from zero fiber; in the neutralizer, the washed precipitate can be used as an anti-frost additive for concrete. It is proposed to use reactor and neutralizer as the main technological equipment.

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