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Enzyme use has provided boost to the technoeconomics of many industrial processes. In this chapter, we summarize different cellulase-based industrial processes for preparation of paper, pulp, brewing products, and different foods. This review presents a brief chemistry and mechanism of cellulose degradation by the cellulase enzyme. Also, cellulase production abilities of many microbial species have been addressed in this chapter. Cellulase plays a major role in production of good-quality paper and pulp. It’s used to debark the biomass and to remove lignocellulosic part. This enzyme also has application in recycling of used paper by deinking and biobleaching. Cellulase enhances freeness and drainage ability of the fibers without compromising the brightness of the fibers. In brewing industry, cellulase in combination of other enzymes is used to extract the more sugar for better-quality alcohol production. Cellulases have a wide range of potential applications in food and beverage processing, production of fruit and vegetable juices, and improvement of methods for extraction, clarification, and stabilization.

Paper and board recycling is now a central issue in papermaking. Understanding of material flows, as a part of the total production chain, as well as, fibrous and non-fibrous component flows needs further clarification. These flows are studied at a European level, with special focus on Germany and Sweden. Non-fibrous components are discussed in terms of a material which hampers the processing of paper and board. Resource-efficiency improvements, in conjunction with economic benefits, are sought and recycling has been able to fulfil both of these. The main drivers to maximize the use of recovered paper in paper and board manufacturing, have been improved over the last decades. These drivers are cost, environmental image and good technical properties to be used as raw material. The increased recycling rate has reduced the quality of the collected paper, produced recycled paper, and replaced virgin pulp. Also, recycling as a process, like deinking, produces large amounts of waste material that has challenges to find proper utilization. These problem areas are addressed in this paper, too. One focus area in the analysis of statistical information is an estimation of the share of non-fibrous components and fibre volumes of paper in Europe (EU) for the year 2010.

The paper and packaging industry is an important part of the global economy and plays a critical role in the world economy. Cellulase, a complex enzyme produced by a number of microorganisms, has tremendous potential application in the pulp and paper industry. Cellulase contributes 10% of the worldwide industrial enzyme demand, and there is tremendous potential for cellulase biotechnology in pulp and paper manufacturing to grow steadily commercially, and to give rise to new possibilities. Cellulase, xylanase, laccase, and lipase are the most important enzymes that can be used in the pulp and paper processes. This prospective study aims to enhance the understanding of the most important advanced uses of cellulases for providing benefits to the pulp and paper industry in various areas like increased pulp yield, improved fiber properties, enhanced paper recycling, reduced processing and environmental problems, and energy efficiency.

Company profiles of major pulp and paper chemical suppliers such as Kemira, Akzo Nobel NV, Eka Chemicals AB, Ashland, Inc., BASF, Buckman Laboratories International, Inc., Clariant, and Nalco Chemicals are presented. Major and niche enzyme suppliers—Novozymes, Enzymatic Deinking Technologies, Genencor, AB enzymes, DSM (Netherlands), Diversa (USA), Kao (Japan), and Tritex etc.—are also presented.

The process to be applied to recovered paper to meet the quality requirements of recycled pulp is determined by the grade of the recovered paper and the demands of the final product. Roughly half of the total recovered papers are recycled for the production of case materials, mainly from old corrugated carton (OCC). Besides these brown recovered paper grades, white recovered paper grades, and some high-quality grades, are reused in newsprint, tissue and other graphic paper grades and in whip top layers of packaging papers, so these have to be deinked. Mixed recovered paper grades are used with OCC and for grey solid board layers and thus are not deinked. Deinking lines are more complex than OCC recycling lines. This is because in addition to the re-pulping and contaminant removal process steps, the pulp has to be deinked, and optionally bleached to achieve high brightness. Removing inks that are difficult to deink, like flexo prints and some digital prints, and ‘stickies’ from pressure-sensitive adhesives, are currently the main challenges in the field of deinking. Some examples of typical recycling and deinking lines for different applications – newsprint, fine paper, tissue, market pulp and packaging paper – are presented in this chapter.

Enzymatic versus chemical deinking is examined for MOW and photocopy prints. Several enzymatic preparations and two fibre/ink particle separation methods are tested. Deinking was monitored by image analysis and standard pulp and paper characterisation procedures. The effectiveness of the fibre/ink particle separation method depends on the ink particle’s size: for smaller particles a washing step is recommended whereas for larger particles, the use of flotation is necessary. The enzymatic treatment is a competitive alternative for MOW and photocopy paper deinking. However, the process requires the selection of an adequate enzymatic preparation for each paper grade.

Recovered paper collection is increasing due to public interest and support. Four important grades of recovered paper include, corrugated boxes, newsprint, high grades like office papers and mixed papers. Recovered paper processing depends on the grade and product quality specifications. Some of the widely used processes and associated unit operations such as pulping, screening, cleaning using hydrocyclones, flotation deinking, dispersion, washing, and bleaching are described.

Waste papers are recycled by deinking. All over the world, the flotation method is the mainstream as the deinking method because of the advantages such as higher pulp yield, less use of water, less area for installation and less total reagent cost. The flotation method is mainly consisted of pulping and flotation processes, the former for ink separation from cellulose, the latter for ink rejecting out from the system. Function to assist the mechanical separation of printing ink from cellulose is required for the deinking agent in the pulping process. In the flotation process, there are three particles, namely, ink, cellulose and bubble, and main four interaction between them in the flotation cell. The following relationship must be held to reject out the ink particles effectively. Vr0

The biotechnological use of xylans and xylanases has grown remarkably. Xylanases have stimulated great interest due to their potential application in several industries. Over the years the number of possible applications of xylanases in the pulp and paper industry has increased steadily, and several applications have been commercialized. Xylanases are being used for prebleaching pulp, modifying fiber, deinking, dedarking, and producing dissolving grade pulp. Apart from its use in the pulp and paper industry, xylanases are also used as food additives to poultry; in wheat flour for improving dough handling and quality of baked products; for the extraction of coffee, plant oils, and starch; in the improvement of nutritional properties of agricultural silage and grain feed; in combination with pectinase and cellulase for clarification of fruit juices; and in the degumming of plant fiber sources such as flax, hemp, jute, and ramie. Use of xylanases could greatly improve the overall economics of processing lignocellulosic materials for the generation of liquid fuels and chemicals. Xylanase and cellulase, together with pectinases, account for 20% of the world enzyme market.

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.

The focus of the research is to build a compact, high performance lightstripe rangefinder using a Very Large Scale Integration (VLSI) smart photosensor array. Rangefinding, the measurement of the three-dimensional profile of an object or scene, is a critical component for many robotic applications, and therefore many techniques were developed. Of these, lightstripe rangefinding is one of the most widely used and reliable techniques available. Though practical, the speed of sampling range data by the conventional light stripe technique is severely limited. A conventional light stripe rangefinder operates in a step-and-repeat manner. A stripe source is projected on an object, a video image is acquired, range data is extracted from the image, the stripe is stepped, and the process repeats. Range acquisition is limited by the time needed to grab the video images, increasing linearly with the desired horizontal resolution. During the acquisition of a range image, the objects in the scene being scanned must be stationary. Thus, the long scene sampling time of step-and-repeat rangefinders limits their application. The fast range sensor proposed is based on the modification of this basic lightstripe ranging technique in a manner described by Sato and Kida. This technique does not require a sampling of images at various stripe positions to build a range map. Rather, an entire range image is acquired in parallel while the stripe source is swept continuously across the scene. Total time to acquire the range image data is independent of the range map resolution. The target rangefinding system will acquire 1,000 100 x 100 point range images per second with 0.5 percent range accuracy. It will be compact and rugged enough to be mounted on the end effector of a robot arm to aid in object manipulation and assembly tasks.

The effect of journal misalignment on the performance of a big-end connecting-rod is analysed in this paper. The misalignment considered varies in magnitude and direction during all the cycle up to contact between the shaft and the bearing. The numerical procedure incorporates misalignment velocities. The technique used for bearing characteristics evaluation (minimum film thickness, friction torque, axial flow) is an extension of the mobility method of BOOKER.

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.

A set of sapphire windows have been inserted in the cylinder liner of a Petter AVI diesel engine. This has enabled the temperatures of the piston ring and piston land surfaces to be measured at various points in the cycle of a firing engine using an infrared emission microscope attached to a storage oscilloscope. In this paper the method is described and some results obtained at mid-stroke and top dead centre are presented. These are compared to previous measurements of the bulk temperature of piston rings taken by other workers.

Fibers such as fabric and bristles can be readily fabricated into a variety of configurations that are compliant and responsive to high-speed or lightly loaded systems. These configurations can be linear, circular, or contoured linear or circular. In this paper visualization and characterization of the complex flow fields in simulated linear bristle configurations as applied to brush seals (bearings) are explored. The full-field flow tracking (FFFT) method is used to visualize the flow field and bristle dynamics, which were nonintrusively determined and graphically reconstructed. Visualization of the flow field revealed regions that are characteristically river, jetting, vortical, cross, and edge flows and exist upstream, downstream, or within the brush. Such flows are caused by variations in fiber packing and stiffness that are both spatial and temporal and strongly influence leakage, stability, and load capacity. Potential applications of brush seals are described herein, and in the appendix a brush seal system design procedure is provided that compares favorably with brush seal leakage results.

This paper presents experimental measurements from laboratory dynamometers of the dependence of the life of automotive timing belts on belt torque and total tension in the transmission of power between two crankshaft sized (19 tooth) pulleys, each with an angle of wrap of 180°. Failure observations of tooth root cracking and of worn belt covers are also presented. Contact loads between belt and pulley teeth have been calculated and it is found that in the conditions of the present experiments tooth load at exit from the driven pulley is the critical load controlling life by tooth root cracking: assuming that this remains the critical load, predictions are made of the effect on life of changing belt tension, pulley size and angle of wrap.

The purpose of this paper is to reveal the relation between flexibility and clearance of oil film by a co-rotating bearing (bush is rotating together with shaft in the same direction and rotation rate), which can be used for sharing load equally in planetary transmission of vehicle. The authors have adopted a theoretical approach of infinite width bearing and explained the characteristics of oil film for co-rotating bearing. Using the numerical calculation to solve the non-linear equation, the authors have gotten the results on finite width co-rotating bearing. By experiments, the relations between flexibility and clearance of oil film for co-rotating bearing are presented by charts in different clearance, rotation rate and load. A good consistency of the results between experimental and numerical calculation result is gotten.

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.

The purpose of this paper is to clarify a universal method to calculate the speed ratio and the power transmission efficiency of rolling contact continuously variable transmissions with planetary cones (differential type CVT). The authors present a new method in which the instantaneous center of rotation and the speed and torque efficiencies were effectively used. This method can be used to derive the equations for calculating the ratio and the efficiency of any types of CVT's and gear drives with complex mechanism. Using the equations obtained in the present investigation, numerical calculations were conducted in the case of a differential CVT with planetary cones. The calculated results agreed well with the experimental ones when the oil churning and bearing losses were taken into account.

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 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.

Experimental investigations on connecting-rod bearings in operating engines required the use of a mechanical scissor linkage to support the wires carrying the electronic signals. In many applications, one end of the linkage is attached to the big-end bearing cap by a yoke, the other end being fixed to the engine frame. The mass and inertia of the linkage modify the load acting to the bearing and change the bearing characteristics. The effect of the mechanical linkage is estimated by carrying out both rigid and elastic bearing calculations with and without a contribution from the linkage to the connecting-rod load. The loads arising from the yoke and links on the connecting-rod were calculated as a function of crankangle for different crankshaft speeds. The calculations showed that the linkage and yoke increase the inertial part of the load diagramm by about 10% and modify the orbit of the bearing center at small eccentricity ratios.

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.

Empirically-derived correlations of dimensionless flow and load are presented as a direct means of predicting cycle-averaged feed pressure and hydrodynamic flows in ungrooved connectingrod bearings which are pressure-lubricated through a crankpin feed hole. The correlations allow quick estimation of flow sensitivity to small engine/bearing dimensional variations, as well as provide a simple relation that indicates when feed pressure flow can be a good indicator of actual flow.

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.

Piston ring/cylinder contacts in modern automotive engines are being exposed to increasingly high temperatures, gas pressure loading and combustion contamination. Conventional ferrous materials and wear-resistant coatings appear to be reaching their limit of reliability and a variety of novel materials, notably ceramics, are being applied to combat the tribological problems resulting from these developments. The tribological behaviour of ceramics in an engine environment is, as yet, not well understood. In particular, there is inadequate knowledge of how lubricants can affect the wear processes, and hence the durability, of ceramics in these applications. As a first step in clarifying these questions, the wear of an alumina-based plasma coating has been compared with that of conventional chromium plating in the Plint reciprocating wear machine. The temperatures, contact loadings and sliding speeds pertaining close to the top reversal point in a high temperature, heavy-duty diesel engine were closely simulated, and the experimental specimens were prepared from real engine components. The wear of the two piston ring coatings responded differently to lubricant additives. The alumina-based coating gave generally lower wear than the chromium plating. Examination of the worn surfaces by scanning electron microscopy and electron probe microanalysis revealed markedly different material removal processes for the two coatings. In these thick coatings damage appeared always to have been initiated at the surface rather than at the interface with the substrate. The possible influences of film formed on the surface by the lubricant are discussed.

Photothermal radiometry is a promising method for the non destructive testing and the characterization of thin materials and has already been suggested to study various kinds of layered materials. A bonding defect at the interface of two materials leads to a thermal contact resistance which is usually low and hardly detectable with the existing NDT techniques. We wish to present here the results of three studies of modulated photothermal radiometry for which such defects can be observed. At first, we have studied several metallic-electrochemically induced deposits. A statistical treatment allows to distinguish various samples, when prepared in different conditions. Then, a similar coating (black polyurethane paint) has been deposited on two plates (steel and glass), for which the bonding strength is known as different. Evidence is given of the existence of an interface thermal resistance for the coating deposited on glass. At last, we have studied the mechanical contact quality between two coaxial metallic pipes. A mathematical model has been developed, including a focalized laser excitation. We were thus able to measure very low contact resistances (about 10-5 S.I.).

This study is to estimate coatings assigned to an use in seawater with regard to their characteristics of corrosion and friction resistance. The main aim is the understanding of interaction mechanisms between electrochemical phenomena and mechanical ones caused by friction. Different studied substrates are a welded high strength steel and a Ni-Cr-Mo alloy, the coatings are or oxides (Cr2O3, A1203-TiO2) or carbides (Cr3C2, WC) with bond-coatings or not. These coatings are atmospheric or vacuum plasma sprayed.

Soft metallic coatings play an important part in many forming processes. Two cases are investigated hereafter: * forging of anti-friction alloy coated plain bearing. Application of a mechanical model shows how it is possible to design the process so that a constant coating thickness in the final bearing wall is obtained. Computation of interfacial strain explains the improved adherence of the coating. * co-extrusion or co-drawing of coated bar or wire. A mechanical model explains coating losses during wire-drawing; in the case of brass coated steel cord, these losses lead to an evolution of surface composition.

The use of Fourier Transform Infra-Red (FT-IR) analysis for the indirect tribological control of thick manganese-iron phosphate coatings on steel substrates has been demonstrated. Using a time series of coated samples and test plain bearings prepared from an intensively used phosphating bath, a strong correlation was found between the lubricated sliding friction, the bearing endurance life and the peak shift and form of the IR spectra. The chemical structure of the phosphate layer as defined by IR analysis of the major functional groups will influence the physical properties of the layer and in turn its tribological behaviour.

Recent developments in chemical vapor deposition (CVD) technology have made it possible to produce thin diamond films on a variety of substrate materials. Diamond, having a very high hardness and low sliding friction coefficient, is a good candidate for tribological applications. Diamond films produced by a hot-filament CVD method often have irregular surfaces owing to the preferred growth mode of the crystals which form on the surface. This investigation using sapphire and bearing steel spherically tipped sliders demonstrated that the morphology of the diamond film surface produces friction coefficients up to ten times those observed in previous experiments which involved smooth diamond surfaces sliding against various solids in air.

In practical applications a rubber-like is often deposited on the internal surface of the housing to improve the bearing performance. In the present work, the influence of this layer on the bearing static and dynamic behaviour is examined by taking into account the housing deformation. A parametrical study is carried out to evalute the influence of different types of housings. It is found that the transmissibility is under-estimated in the case of rigid bearings and that a critical layer thickness exits for which the transmissibility is maximum.

The research and development of proton exchange membrane water electrolysis (PEMWE) is an upcoming and growing area due to a rising interest in hydrogen as an energy carrier. Operating conditions are harsher than in a fuel cell system, particularly because the potentials required for the oxygen evolution reaction are significantly higher. In commercial water electrolysis systems, this is compensated by typically using titanium material sets that are often protected against oxidation through coating processes. Such material choices make small scale research hardware and porous transport layers expensive and difficult to source. In this work, we show that the stability of traditional, carbon-based fuel cell materials such as porous transport layers and graphite flow fields can be sufficient for electrolyzer initial performance characterization procedures such as cell conditioning, a limited number of polarization curve measurements, and electrochemical impedance spectroscopy. We identify and quantify the onset of carbon degradation in porous transport layers with regards to operating length and define a strategy that enables the utilization of standard fuel cell hardware for short-term PEMWE experiments. With the knowledge that existing fuel cell material sets can be applied to conduct electrolyzer research when adhering to such limitations, fuel cell research hardware and experience can be more readily transferred to the younger and rapidly growing electrolysis research field.

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.

In line with the Green Supply Chain Management, Sustainable Supply Chain Management and Natural-Resource-Based Views (NRBV), the present study is as further step of a long range research program initiated in 2004. The project aims to demonstrate municipal bio-waste (MBW) as feedstock to produce bio based chemicals alternative to fossil sourced products. Previous work demonstrated MBW as source of polymeric biosurfactants (BPS) with multiple properties for use in chemical and agriculture sectors. The present paper reports now a new BPS feature, i.e. that BPS are efficient active principles for soil remediation. The study involves three BPS obtained by alkaline hydrolysis from different streams of an MBW treatment plant: the anaerobic digestate of food kitchen waste (FORSUD), the compost (CV) of gardening residues and the compost (CVDF) of a mix of gardening residues, digestate and sewage sludge. The BPS have 5 to over 750 kg/mol molecular weight, characterized by the presence of aliphatic C chains substituted by aromatic moieties and several different acid and basic functional groups. They were used at 0.1–100 g L−1 in aqueous solution to wash soil sampled from an Italian metal polluted site. Collected data statistical analysis was carried out by ANOVA. The recovered washing solutions were analyzed for Cu, Cr, Ni, Zn, Pb. The 50–100 g/L CVDF BPS solutions exhibited 98-81% extraction efficiency, compared to 70-60% for CV and FORSUD. Compared to conventional commercial extractants, CVDF BPS extraction efficiency ranked as CVDF = diethylene triamine pentaacetic acid > ethylene diamine tetraacetic acid > sodium dodecyl sulphate. A new two steps process was studied: (1) use of BPS solution for washing the polluted soil; (2) treating the recovered solution by acidification and membrane filtration to separate a pollutant concentrate from water for further use. Results indicate membrane filtration more efficient and/or sustainable. They confirm BPS as value added products upgrading MBW from societal cost to source of benefits.

Soil-cement bricks were produced using local clay brick waste (CBW) and soft sludge (SS) from fiber-cement industries, preserving raw resources by substituting with industrial wastes. The control formula to produce soil-cement bricks, is 15 wt% Portland cement, 15 wt% sand, and 70 wt% laterite. Clay brick waste was added with values from 10 to 50 % of laterite weight in the control formula. For SS, 5 and 10 % was used to replace the total weight of the dry mixture in the control formula. The samples were shaped by using a manual brick making machine. The results showed that the compressive strength of all by-product bricks exceeded industry standards. The maximum compressive strength was attained for 10 % replacement of laterite by CBW. When using both SS and CBW, thermal conductivity and weight of the bricks were further reduced. However, the percentage of water absorption incorporated into the by-product bricks was higher than that of the control formula but still within permissible limit of the industrial standard for load-bearing applications. All by-product bricks showed lower thermal conductivity compared with the control formula. Soil-cement bricks produced with industry by-products have improved or provided similar properties to control formula soil-cement bricks. The utilization of CBW and SS content in the brick samples can save natural resources, decreasing fuel consumption, and reduce CO2 emissions during delivery.

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

This paper presents experimental data on the performance of parallel plate thrust bearings for a range of loads, speeds and inlet oil temperatures. Several aspects of bearing operation were investigated, including the possible effects of a tapered edge at the inlet to the pads. A careful mapping of the temperature field provided insight into the mechanism of generating hydrodynamic pressures in parallel plate thrust bearings. These temperatures on one hand support the postulate that thermoelastic distortion induced by the temperature gradients normal to the fluid film and the bi-metallic babbitt-metal assembly is responsible for the load capacity of parallel plate surfaces. On the other hand, past and recent experience indicated that a wide spectrum of tribological interactions cannot be treated by the separate approaches that have always been assigned to hydrodynamic action-morpho-morphological effects are at work.

Pivoted-pads thrust bearing are commonly used to support axial load rotating machinary. Analysis of such bearing is complicated by the ability of each pad to pivot, as the rotor is displaced and to translate axially due to the flexibility of the pad support. This leads to dependance of linearized stiffness and damping coefficients on rotor vibrational frequency, pad inertia and support dynamic characteristics. This paper describes an approach based on the pad assembly technique often used to devlop pad journal bearings. A reduced matrix (3,3) can be devoloped once a vibrational frequency is assumed. Conclusions on the role of pivot support and mass pad are derived.

In this paper, two types of the externally pressurized, gas lubricated and circular thrust bearings with the flexible surface are purpose for the purpose of developing the high performance bearings. Their static and dynamic characteristics have been theoretically derived and the effects of the flexiblilties of the bearing surfaces on them have been made clear. From the calculated results, it was discussed which type of the bearings was better in the practical applications, and one of these two types of the compliant surface bearings have been recommended as the high performance bearing.

The purpose of this paper is to report the results of an extensive series of tests on a special tilting pad thrust bearing. The primary interest was to determine the effects on bearing performance of using circumferential pivot locations outside the normal range of 50 to 60% of the pad arc, from the leading edge. Secondary results were also obtained from tests with pad support disks of various diameters, and with pads of different thicknesses.

This paper gives a comparison of theoretical and experimental orbits of a dynamically loaded journal bearing having a pressurised oil Supply to a central 360° circumferential groove. The results of two theoretical analyses are presented: Methods A and B. Method B, referred to as the Reaction Method, features oil film force prediction by means of pre-computed velocity coefficients, thus facilitating quicker computation. Satisfactory correlation of the experimental results with the predictions of both theoretical methods is shown. Comparisons are made for three examples including different relative phase and amplitude of the excitation components at both once and twice rotational frequency.

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.

In this paper, the theoretical and experimental investigations on the static and dynamic charactristics of tilting pad bearing are described. The experiments for indetifying the dynamic properties of journal bearing have been performed by using the machanica PRBS exciter. Good agreement between the measured and the calculated value of the static and dynamic properties has been shown. Either calculation or experiment justifies that the dynamic coefficients of tilting pad bearing vary versus the exciting frequency. It is demonstated in practice that the system under testing can be exceted validity within a wide frequency range by means of mechanical PRBS exciter.

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.

Cold and hot oil mixing at the inlet to a hydrodynamic bearing has been an unresolved and critical problem in determining bearing performance; this is aggravated in the case of starved bearings by the fact that the ratio of recirculating hot oil to cold supply oil is higher than in fully lubricated bearings. The paper provides an experimental investigation of the levels of inlet temperatures in journal bearings for the case of insufficient oil supply. Aside from the customary functional dependence on operating conditions, the additional parameter considered here is the degree of starvation which ranges from full lubrication to only some 10% of the required supply. A correlation is offered that provides an estimate of the expected mixing temperature in terms of known geometric and operational parameters.

In this paper the authors describe experiments which compare time domain and frequency domain approaches to the estimation of the four linearised damping coefficients associated with a squeeze-film vibration isolator. It is shown that while both algorithms satisfy a least-squares error criterion, the resulting coefficients can have quite different numerical values. Whilst the feasibility of both techniques has now been clearly established it is concluded that further work is required to ensure a more direct comparison.

Bearing research at the National Physical Laboratory was initiated by the Lubricants and Lubrication Committee of the Department of Scientific and Industrial Research and was characterised by the work of Sir Thomas Stanton and his colleagues on pressure-distribution, temperature-rise and eccentricity of journal bearings. Aircraft turbines introduced high-speed bearings and much theoretical work was stimulated by the so-called ‘thermal wedge’ effect. With the formation of the Mechanical Engineering Research Organisation (now N.E.L.) the N.P.L. lubrication group was transfered to temporary Laboratories at Thorntonhall in Scotland and reinforced by additional staff to constitute a multi-disciplinary team devoted to research on Lubrication, Wear and the Mechanical Engineering Aspects of Corrosion. This paper summarises that portion of the work of the two laboratories which was concerned with hydrodynamic and hydrostatic bearings. The Department ceased to exist in 1964.

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.