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Paper derived from lignocellulose has great advantages over plastics as packaging material, nevertheless, the poor water- and oil-resistances of paper-derived products limited their application in high-end field. Herein, novel dimer acid-based waterborne polyurethanes (DWPUs) with different content of dimer acid-based polyester polyol (DG) were prepared and used as water- and oil-resistant coating for paper substrate. The effects of DG contents on water- and oil-resistances, mechanical properties and thermal stability of DWPUs coated papers were systematically investigated. When the content of DG reached up to 7 wt% (based on polyester glycol), the paper coated by DWPU exhibited 88.06% decrease in Cobb 60 value, 8.7 times increase in kit rating compared with uncoated paper. Meanwhile, DWPUs coated papers showed good mechanical properties and thermal stability. These improvements are attributed to the flexible long-alkyl chain, and six-ring structure of DWPUs as well as the continuous and homogeneous DWPU-derived membrane on the surface of paper. This study provides a new framework for the preparation of high quality, multifunctional, environmentally friendly water- and oil-resistant coatings for paper substrates.

Sustainable and low-cost cellulose-based metallisation is the prerequisite for wearable and disposable electronics fabrication. In this paper, to realize the simplified, low-cost and high efficient metallisation, a new method had been proposed without both the noble metal activators and the corrosive chemicals. The modified electroless plating processes had been employed in activation and deposition procedure. The nickel ions were first physiadsorbed on the cellulose paper (CP) fibers and then reduced into clusters by reducing agent which can act as the seeds to initiate the electroless plating process. The gold galvanic displacement was conducted further to modify the nickel surface. Via these processes, the cellulose paper was metallised with Ni-P and Au/Ni-P successfully. The morphological and microstructural properties of the resulted Ni-P/CP and Au/Ni-P/CP hybrids were evaluated. The Ni-P/CP composites had a low surface resistance below 0.5 Ω sq-1 while the Au/Ni-P/CP composites are below 0.1 Ω sq-1. The relationship between the mechanical and electrical properties with the plating parameters is discussed. The results indicated that Au/Ni-P/CP had good electrical conductivity and mechanical flexibility. Finally, the application demonstration for supercapacitor with the modified metallisation method was exhibited. This work offers a facile and non-toxic path to develop high-performance metallisation for functional cellulose-based materials.

Significative growth and demanding for premium tissue products, in which softness and absorbency are key consumer requests, pointed out the need for the establishment of relations between fiber properties and tissue paper properties. For this purpose, an experimental plan was designed using a representative group of pulp fibers, six hardwood, and six softwood, for the production and characterization of low basis weight paper structures (20 g/m2). The pulp fibers morphology and chemical content were evaluated, and hardwoods showed lower fiber length (0.70–0.84 vs 1.57–1.96 mm), coarseness (6.71–9.56 vs 16.77–19.66 mg/100 m) and higher pentosan content (6.3–21.1 vs 7.6–10.3%). Even though the paper structures were produced with the same basis weight, they presented a broad range for bulk (3.46–8.04 cm3/g), tensile index (2.00–11.45 N.m/g), softness (65.7–86.9) and absorption capacity (8.08–9.48 g/g). The results indicated that softness was directly influenced by structural properties, increasing with bulk, while tensile strength correlated inversely. Therefore, the correlations obtained were used to identify the most suitable pulp fibers properties for each type of tissue paper. Keywords: Absorption, Cellulose fiber materials, Pulp fiber morphology, Softness, Tissue papers

This Special Issue of the International Journal of Fatigue contains selected papers presented at the International Conference on Multiaxial Fatigue and Fracture held in Seville, Spain, on 1–3 June 2016.

Publisher Summary Paper consists of a web of pulp fibers, usually formed from an aqueous slurry on a wire or screen, and held together by hydrogen bonding. The same basic steps are involved for either hand- or machine-made paper. The steps are: forming (applying the pulp slurry to a screen), draining (allowing water to drain by means of a force such as gravity or a pressure difference developed by a water column), pressing (further dewatering by squeezing water from the sheet), and drying (air drying or drying of the sheet over a hot surface). The paper machine is a device for continuously forming, dewatering, pressing, and drying a web of paper fibers. The most common type of wet end machine was the fourdrinier, where a dilute suspension of fibers is applied to an endless wire screen or plastic fabric. Water is removed by gravity, or the ΔP developed by table rolls, foils or suction equipment, and the drilled couch. The web at this point is 18-23% consistency. More water is squeezed out in the press section to a consistency of 35-55%. Finally the sheet is with steam heating in the dryer section. Modem paper machines can be quite expensive, costing up to several hundred million dollars each.

This chapter provides an overview of the pumps that are used in pulp and paper industry. In pulp and paper industry, high temperatures, very high suction pressures, low NPSHR requirements, poor lubricity, air entrainment, corrosive and acidic mixture of sodium or calcium bisulfite and sulfurous acid, and reliability are major considerations. The standard small process pump in pump and paper industry is the end suction, ANSI B73 or ISO 2858 chemical pump with centreline discharge open impeller and today more often than not mechanical seals. The larger pulp and low concentration transfer pumps are end suction, open impeller and adjustable wear plate, packing or mechanical seal type pumps with centerline discharge. Centrifugal stock pumps are used for consistencies up to approximately 5.5%, above this there are pumps with special internal features such as an inlet fluidizer that will allow consistencies up to as high as 18% consistency to be pumped. The pumps in the paper machine area are the screen, refiner, washer, cleaner and head box units as well as the refiner reject pump.

This paper discusses the mathematical modeling, dynamic simulation and validation of the entire digester area at the Tumut Mill: the Lo-LevelTM feed line, the Lo-LevelTM heat exchange and recovery system, and the digester itself—a Lo-SolidsTM EMCCTM singlevessel hydraulically-full heterogeneous reactor. The mathematical description of the digester is a modification of the extended Purdue model, a rigorous framework based on the fundamental principles of mass and energy conservation. The heat exchange units —shell-and-tube heat exchangers, condensers and kettle reboiler—are introduced considering an interlinked-cell model approach. The underlying mathematical formulation consists of a large number of differential-algebraic equations (DAES) which result from the lumped-parameter approximation used to describe the several process units. An open architecture solution is developed, and the set of equations are codified using gPROMS and C++ programming languages. The agreement between the model predictions and the experimental information from plant data is reasonable, thus providing a model-based framework for future research.

Publisher Summary This chapter discusses paper-coating rheology. With the advances in theological testing methods and computational tools, the understanding of the blade coating of paper is improved considerably. Coating of high solids gives the paper less chance to roughen upon contact with water and the coating layer does not sink into the paper web. The application of paper coating has a unique aspect in the sense that the clearance between the blade and the web is only one order of magnitude larger than the pigments in the suspension. However, high solids content naturally brings challenging rheological problems. The importance of water retention on the ability of a coating to operate at specific conditions is one significant step. However, paper coating still offers a number of challenges, as high speeds and high solids are desired. Still, the small scale between the blade and the web requires a better understanding of the small-scale microstructures that can form under the blade. A direct comparison of a complex fluid dynamics calculation and pilot scale results has yet to be accomplished. These issues should become clear because efforts are made to understand the role of rheology in the blade coating process.

This paper examines the various tribological aspects of generation and control of tyre to road traction. The basic laws of dry friction of rubber are described and experimental results of boundary lubrication of rubber-solid interface are presented. An analysis is given of the tribo-elastic interaction between frictional properties of rubber and the elastic properties of the tyre to explain the three regimes of traction of a slipping tyre on dry and boundary lubricated roads. The state of the art of wet road traction and the techniques of “delubrication” of surfaces are described and correlated with the different mechanisms of elastohydrodynamic lubrication. Traction on wet roads is considered as a problem of partial EHL. A detailed formulation and analysis of this problem is given based on a simplified model of a “choked film”. The paper ends with a discussion of semi-empirical and pragmatic approaches of modeling traction.

This paper reviews the impact of current and future market and legislative needs on tribological aspects of piston assembly design. Emissions, durability and refinement are highlighted as key issues. The paper commences by discussing the influence of the piston assembly upon hydrocarbon emissions and practical issues associated with crevice volume reduction. The development of theoretical studies of piston ring lubrication is then reviewed briefly, prior to consideration of oil consumption, with particular significance placed upon the very low levels of oil consumption required to satisfy forthcoming particulate emissions legislation for diesel engines. Piston assembly friction accounts for approximately half of total engine friction and is, therefore, a primary target in the quest for lower fuel consumption and the consequential reduction in gaseous emissions. Piston assembly design development to reduce friction is discussed prior to a review of empirical and theoretical studies of piston assembly friction. This leads to a brief discussion of the theoretical analysis of piston dynamic behaviour and skirt form optimisation. Throughout the paper practical problems associated with achieving durability and other performance criteria are highlighted.

Low Elastic Modulus (LEM) coatings are thin polymeric or elastomeric layers bonded onto a rigid substrate. This type of coating offers some distinct advantages in protecting working surfaces from damages. Indeed, a thin, rigidly backed, rubber layer allows the easy formation of a lubricant film in conditions where a very hard steel surface would fail. Additional advantages of LEM coatings are their capacity to attenuate the excitation of vibrations and to reduce the transmission of vibratory forces and shock loads. Furthermore, the ability of rubber coatings to deform rather than to break makes LEM contacts particularly tolerant to the presence of solid contaminants. In this paper, the benefits to be gained from the use of a thin, soft, layer on one of the two surfaces of a rotary or sliding contact are examined, with special reference to the lubrication problem of the guiding contacts of rolling element bearings. The case herewith presented refers particularly to the lubrication of the cage pocket of a medium-size Spherical Roller Bearing. A specially developed Finite Element program is applied to study the EHD lubrication characteristics provided by LEM coatings. The analysis is extended to investigate the effect of variation of a few basic design parameters on the strength of the contact. An important advantage of the present numerical solution is its ability to tackle problems with complex geometries and non-homogeneous materials, usually found in industrial applications. The computational examples discussed in the paper clearly illustrate the power and versatility of the method in dealing with practical design problems.

Traction drive is the method of transmitting power through the EHL oil film existing between a pair of rotating bodies. A traction drive CVT as an automotive transmission must transmit a large amount of power in a limited space. Therefore, the conditions of such traction drives are very severe. The authors observed the traction surface of a disc after the endurance test by means of a scanning electron microscope and made theoretical examination of the oil film thickness of the traction drive for automobiles as well. By using a basic prototype of the half toroidal CVT, variations of slide/-roll ratio versus high oil temperature were also measured. The test data is presented in this paper.

Applying EHL theory, the paper derives the mathematical model for analysis of lubricating of cylinder sleeve and piston ring, and composes a general CAD program for computation of the thickness of lubricant film, by which anlyses can be made to the lubricating state of cylinder sleeve and piston ring for engines of various models with different operating mode. Tests of specific point on bench in specific conditions show that the computing method is feasible.

The continuing evolution of the internal combustion engine, together with required improvements in component design lead times and reliability, places increasing demands on improved design and applications engineering techniques. This paper charts the evolution of predictive design techniques for selected components within the engine and outlines the anticipated trends and developments necessary to meet the challenge of future design requirements.

Traction drive CVT (Continuously variable transmission) for automobile use requires a big torque capacity, and the temperature of the traction fluid filled in CVT sometimes rises to 140 °C. To achieve stable power transmitting under this condition, it is necessary that traction coefficient of the fluid is sufficiently higher than the designed value of CVT. For the purpose of developing the excellent CVT fluid which enables stable power transmitting even at high temperature, we have studied the quantitative correlation between the molecular structures and traction coefficients at high temperature. In this paper, we describe the relationship mentioned above and experimental result of practical CVT test.

The paper deals with the results of experimental and theoretical research carried out within the Laboratory of Mechanical Seals from Machine Elements and Tribology Department of the Polytechnical Institute in Bucharest, special attention being paid on the studies concerning engine water-pumps mechanical seals.

This paper gives the General Motors (GM) perspective in vehicle tribology. Tribology plays an important role in vehicle durability, reliability, and fuel efficiency. While several areas in the vehicle are included, major emphasis is given to engine tribology. Piston skirt, piston rings, crankshaft and its bearings, and the valve train are identified as the most critical reciprocating engine components for tribological investigation. In addition to discussing these, engine friction, engine lubricants, clutches and brakes, and sheet metal forming are briefly covered. In each case the tribological state-of-the-art, as applied in design, is identified. GM's analytical and experimental capabilities are discussed, and areas where more work is needed are identified.

Many coatings have been developed in recent years but their use in machinery is hampered by the lack of design methods for coated elements. While it is quite clear that the limitations in design methods of homogeneous elements used in rubbing contacts, and which relate essentially to the surface as opposed to the bulk aspects of the problem, apply also to coated elements, it is possible to develop methods which will help choose coating/substrate combinations that can withstand the mechanical and thermal loads applied to the contact by the mechanism under study. This paper discusses these methods and suggests that if they were applied to the rubbing elements or first-bodies, they could identify non compatible combinations under the working conditions envisaged and thus eliminate a large part of the trial and error process which is current today in the choice of coatings. Mechanical and thermal characteristics, thin layer solid mechanics theories along with a general pluridisciplinary approach are needed if these methods are to be developed.

Damage, be it breakage, deformation or wear is initiated by overstraining or overstressina. Full modelling of both these causes is not possible today and one resorts to “simulation” to produce the data needed by design engineers to predict function loss. The question then is: how reliable is the data furnished by simulation? The answer is brought by the analysis of data produced in fretting tests which show that even very small variations in running conditions, in this case in amplitude, can change the nature of the damage. Simulation tests have to be undertaken with the utmost care.

Traction drive contact optimisation requires the investigation of trends in performance and durability to find the best combination for a given application. While information relating to contact efficiencies and capacities has been around for some time, it is not immediately obvious which practical steps the designer should take to improve his creation. The results of the parametric study presented here should help to clarify matters and the brief review of factors which influence rolling component life will give an appreciation of the ‘other half’ of the optimisation process.

A mass-conserving simulation algorithm for cavitating hydrodynamic lubrication has been described elsewhere. The algorithm, which is particularly well adapted to finite element implementation, is outlined qualitatively and demonstrated quantitatively through real and ideal engine bearing applications studied previously by others. Present simulation results and previous data agree reasonably closely for these applications, providing a limited validation of the present algorithm and demonstrating the importance of mass conservation in engine bearing design analysis.

The running-in wear of auto-motive cam-follower systems is assessed from tests carried out using a motored PSA TU3 cylinder head. The changes in surface topography occurring through wear is examined as a basis for establishing an objective method of wear evaluation. The effects of variations in the Initial surface finish and hardness of cams and followers is evaluated using a specially instrumented MIRA Test Machine in which the effect of hardness difference between cam and follower is highlighted and the implications of surface finish variation are examined.

Taper bushing, so-called the taper lock bush, on the market are commonly used with a key. If the limit of the transmissible torque by the taper bushing without a key is made clear, the use of the taper bushing would be more widespread. In this study, the maximum static transmission torque of the taper bushing without a key was experimentally discussed. The experimental data was considered in terms of the multiple regression analysis, and a regression equation for the transmissible torque was obtained.

The modern concept of a car wheel bearing is a complete unit that is ready to use, greased and sealed for life. Thus today the lubricant and the seal form an integral part of the bearing. With ongoing improvement in bearing internal geometry and materials, the performance of the seal can even replace rolling contact fatigue as the limiting factor for bearing service life. At the same time, demands for reliability and long, service-free running periods are continuously increasing. Systematic efforts during recent years have resulted in improved seal designs and have provide deeper insight into their functioning and the tribology effects involved. Seals for grease lubricated bearings are defined as active hydrodynamic engineering elements, with a preferential outward pumping effect to prevent penetration of foreign matter into a bearing unit. Seal life is thus governed by the existence of preferential pumping effects. When these have vanished, the seal transforms from an active into a passive engineering element. Bearing life from then depends on environmental factors only. Several mechanisms were identified which influence these effects negatively and thus restrict seal life: of these ageing of the seal lip material and counterface abrasive wear are described. Limiting factors were found and incorporated in a seal life model.

In recent years, the great improvement in the materials for the rolling elements and the development of the new traction oil has increased the reliability of the traction drive CVT (Continuously Variable Transmission) for automotive use. The authors began the research and development of the Half Toroidal CVT in 1978, and have made types of prototypes. Traction coefficient and efficiency were measured and life tests were carried out succesfully. As a result of these studies, we conclude that traction drive CVT has the potential for application to automotive transmission.

Methods of calculating oil flow in connecting rod big end bearings are discussed and a numerical example typical of engine practice is presented. The commonly used oil feed arrangement for connecting rod bearings, consisting of a single hole emerging from the crank pin, results in small flows and the bearing oil film may be depleted. It is therefore necessary to consider a rigorous ‘oil film history’ model where the transportation and availability of oil in the bearing clearance is allowed for. Cycle-averaged oil flow results for over 150 bearing cases are summarized in design chart and equation form. The design charts are of two types, one relating the flow from the rigorous oil film history method with the oil flows based on rapid methods. The other type considers directly the many engine and bearing parameters involved thus making this technique suitable for general use. Also included are sensitivity charts showing the effect on oil flow of changes in particular parameters.

Synopsis Previous work on brake noise and vibration problems is reviewed from its beginnings up to the present day. An underlying theme is revealed; namely that the inadequacy of analytical approaches in leading to satisfactory designs has forced the industry to develop empirical fixes when brake noise and vibration problems occur in practice. Despite having developed skills in tackling practical noise and vibration problems, the brake industry has a pressing need for design tools to avoid such problems from the outset. The growing importance of customer complaints of brake noise and vibration - against a background of increased overall vehicle refinement - provides an obvious commercial motivation. Suggestions are made of how to enhance FE models of the brake assembly in order to develop such design tools.

This work presents a forecasting model of the wear risk for an automotive overhead camshaft and its confrontation to experimental results. This model was built on the specific oil film thickness calculation and on the subsequent calculation of the coefficients of friction and stresses, the corresponding values being then compared with threshold values. Organized as a piece of computer software, the model permits the calculation of overall wear factors; the most significant parameters are thus presented as curves related to the cam profiles in such a way that the occurence and localization of wear is predicted with a rather good agreement with results obtained on rigs, for different operating conditions.

In practice rotary shaft seals will experience a small-amplitude dynamic excitation. It is shown that under periodic excitation circumferentially nonuniform clearances develop due to viscous seal material behaviour. The nearby fluid will fill these gaps, so entrainment and squeeze effects can develop fluid pressures which are sufficiently high to overcome the radial preload. Viscous seal properties are essential in this type of EHD lubrication. Hence it is designated viscoelastohydrodynamic (VEHD) lubrication. At present, this lubrication concept is the only macrohydrodynamic theory that explains the existence of a consistent circumferentially nonuniform film geometry of appreciable dimensions. Moreover, calculated values of film thickness and friction are in agreement with experimental data.

Synopsis The durability of the cam and follower contact of the valve train of automobile engines has proved to be suspect in recent times. The received wisdom as to the mechanism of operation is that boundary lubrication pertains during the loading cycle. This view may well have delayed the application of fluid film lubrication theory in the study of the device. Modern thinking would lead to the view that some element of elastohydrodynamic lubrication must be occurring and that the mode of lubrication would be better described as ‘mixed’. The situation is reviewed and it is concluded that the use of lubrication theory as a design tool, alongside traditional tribological approaches, has much merit.

Friction clutches and brakes are analysed by the methods of computer-aided analysis. Clutch/brake rotational dynamics and friction and wear are considered jointly. Mathematical model and numerical algorithm for computer solution of dynamic equations are developed. Computer programmes provide generation and detailed analysis of design variants. An optimum design variant can be selected according to a specified criterion. The computer programmes developed are tested with transport engineering problems and some of the numerical results are presented.

Synopsis Developing a high-performance engine requires the capabilities for simultaneously predicting and studying the desired functions and quality of the entire engine at the initial stage of the development process. Vigorous effects have been under way at Nissan to advance the use of tribological technology in R&D activities for new engines and their components. Approaches used up to now have generally treated engine technology in terms of two categories: component technology and assembly technology. Crankshaft bending analysis, which takes into account the oil film pressure distribution, and cylinder bore distortion analysis, based on bolt tightening torque, are examples of techniques used in the component technology category. Engine friction prediction model and lubrication system model are typical tools used in the assembly technology category. It is expected that computer-aided tribology will continue to advance as various technological issues are overcome in the future.

In this study, fertilizer drawn forward osmosis (FDFO) process was applied for the treatment of shale gas wastewater. The forward osmosis (FO) experiments with simulated shale gas wastewater and real shale gas wastewater were carried out, respectively. The effects of reverse salt diffusion on the inorganic fouling to the membrane surface was systematically investigated. Two commercial FO membranes were selected and the optimized operating conditions were evaluated. It was found that calcium sulfate scaling can be alleviated by optimizing the operating parameters, including increasing flow rate and decreasing temperature. Furthermore, the Aquaporin FO membrane, which has lower reverse salt flux and less surface charge potential, exhibited lower fouling tendency. Under the optimal operating conditions, the effects of reverse salt diffusion on the barium sulfate scaling were also analyzed. The presence of calcium ions can alleviate barium sulfate scaling, while sodium chloride will aggravate the barium sulfate scaling. In addition, the scaling behavior of real shale gas wastewater was further explored. Inorganic scaling phenomenon seriously affected the FO membrane performance and lower pH had beneficial effect on recycling the real shale gas wastewater. The present study provided both theoretical fundamentals and industry applicable practices for implementing FO technology in the treatment and resource recovery of shale gas wastewater.

Synopsis Considerable attention has been focussed upon the mechanical power losses in internal combustion engines in recent years. Broadly speaking these may be of the order of 15% of the fuel energy. Most of these losses can be attributed to the friction associated with the lubricated machine elements in the engine, namely piston ring assembly, bearings and valve train components. Development of the understanding of the operational characteristics of dynamically loaded engine bearings and piston rings is more advanced than that of the valve train, particularly the cam and follower. The work described in the present paper represents part of a continuing study of cam and follower lubrication characteristics. It is widely thought that the cam and follower contact operates with a degree of surface interaction for virtually the whole of its cycle. As an initial step towards the understanding of surface topography influences, a rigid surface model for the mixed lubrication of a cam and follower is developed in this paper. Results are presented to demonstrate the effect of surface roughness and its distribution upon nominal film thickness, the load carried by the asperities and power loss. The proportion of the total load carried by the asperities and the proportion of power loss associated with asperity contact are detailed. The influence of lubricant viscosity and camshaft speed upon nominal film thickness during the cycle are also discussed.

This chapter discusses modifications and inventions of Early Victorian paper-making machines. By 1843, Lemuel Wellman Wright had moved to North Wales where he was a paper-mill engineer. He invented a number of notable improvements to the cylinder-mould machine. This cylinder was a single or Yankee type, of large diameter, and the paper was stuck onto it by the wet- or over-felt as it came from the cylinder-mould. During the passage of the paper over the cylinder, it was pressed against it by three or more press-rolls, which were held against the cylinder by lever arms and weights, and were not driven except by friction against the cylinder, or rather against the paper as it stuck to the cylinder. With regard to the four rolls driven by friction on the surface of the cylinder, the two rolls marked (K) were pressing-rolls, and those marked (M) were steam-heated smoothing-rollers. In this way, he made a very highly machine-glazed paper. This appears to be the first time that this type of paper was made. Lemuel Wellman Wright claimed that the surface was far better for writing upon than that of any other paper previously made and that it gave excellent impressions for printing purposes.

Thirty-three rolls of rotary gravure papers—type: 70 per cent ground wood, 30 per cent wood pulp—taken from different productions or of different quality were received from eleven paper mills in Finland, Sweden, Austria and Germany. Felt and wire side of these papers were printed on a modified rotary gravure machine under constant and controlled conditions at 10,000 and 16,000 r.p.h. The testing of different stocks and sampling of printed and unprinted test sheets from six different roll locations were examined for consistency in quality between production runs as well as within one roll. One “solid” of the prints was objectively measured with the FOGRA Variance-meter for degree and uniformity of optical density. The results were compared with the subjective evaluation of various observers and showed a good correlation. The visual evaluation of quality was made in respect of “quality in middle-tone”, “tone reproduction” and “show through”. The following characteristics of the papers were determined by laboratory methods: smoothness on Bekk, Bendtsen, percentage of contact, and proof printing for evaluating the point of coverage and for visual evaluation at 1.5 g/m2 inking; absorbency against oil and gravure inks and evaluation of contact angle; compressibility on Bendtsen, percentage of contact, Laraignou and Breeht-Schalder; optical properties; brightness, opacity and gloss; evaluation of abrasive tendency. The various laboratory proofing methods were tested for evidence of the printability of rotary gravure papers, i.e. the correlations between the individual objective and subjective quality evaluations and the measured single properties were calculated.

Superhydrophobic surfaces have attracted great attention for their distinguishing properties. The key factor for a surface to achieve superhydrophobic is the intrinsic hierarchical structure. Traditional graphene based materials are not suitable for the construction of hierarchical structures because these planar materials will adhere to the substrates during preparation. In this paper, based on the exhaustive experimental results and systematically analysis of the interaction mechanism between p-phenylenediamine and graphene oxide, it is proved that p-phenylenediamine modified graphene oxide has better strength, and it can be used to prepare super-hydrophobic surfaces with micro-nano hierarchical structures. The approach described here could be applied to the construction of superhydrophobic graphene related coating without other rigid supporting materials. Keywords: Graphene oxide, p-Phenylenediamine, Superhydrophobic, Hierarchical structure, Coating

Thermal effects in hydrodynamic lubrication were recognized as very important since the first works in this field. This paper presents the evolution of research concerning thermal effects in hydrodynamic bearings from the first study published by Hirn in 1854. A summary of general thermoelastohydrodynamic theory for the journal bearing case and its comparison with experimental results is then presented.

The major contribution of A.G.M. Michell to the science of lubrication through his three dimensional solution to Reynolds' equation is well-known. Much less known is the story of the industrial introduction of tilting pad bearings to Europe and the eventual establishment of a specialist bearing company carrying the inventor's name. The purpose of this paper is to relate something of this history and then to highlight some of the subsequent technological changes encountered by the company, Michell Bearings, in the 65 years of its existence.

The prediction of heat generation and final operating temperature of high speed angular contact bearings is of considerable importance in order to control operating clearances in service, as well as providing the basis for an understanding of the local lubrication parameters. This paper develops a technique whereby the heat generated within the bearing can be estimated, and hence track temperatures assessed.

Synopsis The thermal analysis of plain journal bearings is a complex matter and this may be particularly true for bearings of the self-contained type. The lubricant feen temperature is generally not know for self-contained bearings and is mainly a function of the capacity of the bearing to dissipate the heat generated within the lubricant film. A further difficulty arises from the fact that the thermal environment may be different for specific applications of a particular design. The purpose of this paper is to demonstrate a thermal network analysis for predicting the performance of self-contained journal bearings. Theoretical predictions have been made for the performance of a 110 mm diameter ring-oiled journal bearing and a comparison undertaken with experimental results for a projected bearing pressure of 1 MN/m 2 and an average ambient temperature of 23°C.

Waste mud from the waste water treatment plant of an iron and steel factory has been investigated due to the recovery possibility of the magnetic materials. Mud samples was firstly expired due to the its chemical content with an XRF spectrometric method. Due to the XRF spectrometric analyses the mud sample had 30.72% magnetic content. This result motivated the experimental study. Dried mud sample grinded and sieved to define the particulate size and it is determined that about 66.67% of has the grain size lower than 50 µm. To gain the magnetic content efficiently, Jones type magnetic separation has been done under 17,000 Gauss on four different mud samples. It is determined that 69.59% of the mud sample compost of magnetic materials and 51.83% of this rate is simply iron base due to the XRF spectrometric analyses. As a result, 36.06% of the mud is the iron, 33.53% magnetic content out of iron and 30.41% is nonmagnetic composition. Economic value of the wasted potential is about 969,292.8 $ annually. The payback period estimated approximately about 10 months, by the investment of a separation units these are costs about 750,000 $ and annual electricity consumption is 64,751.8 $. Keywords: Waste metal recovery, Magnetic separation

A good understanding of the failure mechanisms and of their controling factor are needed to combat wear. Wear particle analysis is a powerful tool in analysing surface deterioration. Furthur, the examination and analysis of worn surfaces give indications about the changes brought about by relative motion. Finallty subsurface modifications can influence wear mechanisms. In this work, specific tests are carried out to study these parameters. Two types of surface failures, scuffing and fatigue scoring are investigated. Experiments were performed on a high performance disc machine in which rolling and sliding are controlled for different normal loads. Wear particles are monitored. The disc surfaces are examined after each loading step and metallographic examinations are conducted. Weight loss variation, temperature, and friction force variations are discussed.

The historical development of 2D and 3D bearing analyses is described and discussed. Data for the convection coefficients at the back face of thrust pads is given and correlated against standard variables. From the use of these data in a simple analysis it is suggested that the “double layer” pad could operate at substantially lower temperatures then standard pads. A 3D analysis program is used to show the benefits of relieving parts of the support circle in button insert pads.

There have recently been rapid advances in our understanding of Taylor-Couette flow between a rotating inner cylinder and concentric stationary outer cylinder. This process is reviewed and its implications in the case of ecentric or journal bearings considered.

The problem of boundary conditions, film rupture, cavitation or film extend is broadly under discussion for steadily loaded bearings without significant effect to bearing characterstics. Much more influenced are dynamically loaded bearings by different theoretical boundary conditions. By experimental investigation of bearing under dynamic load-measuring journal centre path and pressure development-with speccial load patterns revolving sudden change active film yield, that under normal pressur oil feed there is no rupture, pressure disturbance or reduction of load capacity.

Experiments were conducted on a thrust bearing of 0.8 m outside diameter and 0.4 m inside diameter with 3.25 M Pa unit pressures. Experimental results were obtained for different load and speed combinations and the parameters measured were pressure distribution, temperature distribution and film thickness at leading and trailing edges of the bearing pad. The experimental results were compared with the analytical temperatures obtained by solving the established steady-state Reynolds equation for incompressible lubricant and the energy equation. Heat balance was also made between the heat generated in the lubricant film and the heat dissipated to the surroundings of the thrust bearing pads in the bearing housing.

As part of a continuing study of the effects of film reformation in plain journal bearing, an experimental programme with grooved, rectangular pad, slider thrust bearings has been undertaken. For such a pad with lubricant supplied under pressure to a central groove an oil-air interface may form between theh pad and the opposing runner. Under specific operatings conditions instability of this interface was observed and the study reported was undertaken to elucidate the mechanism of this characterizing the instability is identified, and the ingress of air into the lubricant film immediately proir to interface collapse is shown to occur. It is postulated that this is the basis of the mechanism of instabiltity.

The field of metal forming together with technology in general went in recent years, through many breakthroughs, both in basic understanding and in application. In this manuscript, selected, but not all, areas of impressive progress will be covered. First the state of the art in manufacturing will be described, then the analysis, and experimentation that contributed to practical developments will be forwarded. Beyond the state of the art, some venture into prospects is undertaken. Progress in automation is typified by the description of an automated forging press. Hot, cold and warm forming are compared, covering forming at room temperature and up to forging from the melt. Hard and soft tooling are presented. Also, methods for replacing brute force with finesse are typified by rotary forming. The study of metal forming through physical and mathematical modeling is followed. Small scale modeling, wax modeling and the different analytical procedures like equilibrium, slip line, upper bound and the finite element methods are evaluated.

The concept behind the SNAP-50/SPUR nuclear-electric space powerplant is presented and the present status of the program is reviewed. It is found that a suitable technological base already exists from which an orderly program can proceed initially to feasibility demonstrations of the reactor and power conversion components and ultimately to a demonstration of an experimental powerplant. Nuclear-electric powerplants based upon this technology can have a variety of applications in the national space program beyond 1975.