Search

The tensile bond strength is one of the main properties of rendering mortars. It represents the adhesiveness ability between the mortar itself and the substrate. This property depends on several factors, such as the proportion and characteristics of the mortar materials and the substrate, along with the mode of application and climate conditions. The purpose of this paper was to analyze the tensile bond strength between three rendering mortar proportions in volume – 1: 1: 6, 1: 2: 9, and 1: 6 (with plasticizer additive) – each one applied on two substrates, ceramic structural blocks with roughcast and concrete structural blocks. The rendering mortars had their physical properties evaluated in fresh and hardened stages, as well as their compressive and tensile strengths in flexure. The tensile bond strength was determined by a pullout test on ceramic and concrete masonry walls exposed to external weather. The results showed that the 1: 1: 6 mixed mortar exhibited higher tensile bond strength in both substrates of ceramic blocks with roughcast and concrete blocks without preparation. Besides, among 1: 2: 9 and 1: 6 mortars there is no significant difference in tensile bond strength considering both substrates. Another conclusion was that the substrate type did not affect the final bond strength between the mortars.

The understanding of the mechanical fixation behavior of coatings is crucial for a better comprehension of the bonding systems, especially at the interface between the mortar and the substrate. Physical adherence is related, among other things, to the contents of the materials used in the roughcast and mortar coatings, due to the colloidal water penetration into the pores of the substrate. This work evaluated the influence of different lime solution additions replacing the kneading water in the preparation of roughcast and mortar coatings. Two types of substrates were investigated:ceramic bricks and concrete blocks. Three wall masonry panels were constructed, with dimensions of 220 × 180 cm2, one of concrete block and two of ceramic bricks, followed by the application of roughcast and mortar coating with an average thickness of 5 mm and 20 mm, respectively. Direct tensile bond strength tests were performed and the results, with a 95% confidence level, showed that substrate ceramic and treatment in the roughcast exhibited a better behavior regarding the distribution of the tensile bond strength of the tested specimens. However, no significant differences of the amount of addition used (0%, 5%, 10% and 15%) on the tensile bond strength were observed.

Mortar bond covering systems are multilayered and applied to a base, composed of render mortars (stucco, plaster) followed by some decorative element for a finishing touches (paint, ceramic plate, ornamental stones, etc.). In order to homogenize the characteristics of the base material and to increase the bond with the render mortar, it is a common practice to apply some type of preparation, either an even, smooth solution such as wetting the walls, or roughened solution utilizing roughcast. Studies have shown that the presence of calcium ions in ceramic bases results in the formation of a more dense crystalline structure at the interface, which culminates with higher mechanical bond strength. In this light, the present study presents an experimental investigation, the purpose of which is to evaluate, in a comparative way, the direct tensile strength of bond of a mortar coating applied to the same base, preceded in its application by five different preparation techniques. It can be concluded from this study that the preparation of the mortar base is of fundamental importance for bonding strength and, therefore, the addition of a lime solution to the roughcast is economically feasible and a satisfactory alternative in order to obtain positive results in environments where bond strength is critical.

Adherence is one of the main properties of rendering mortars. Pathologies related to the lack of adherence between the mortar and the ceramic block are frequently seen, especially on facades. A complex system with several variables influences adherence, where the sorptivity of the ceramic block can be highlighted. The objective of this work is to verify the influence that the sorptivity of the ceramic block has on the mortar adhesion in different combinations. Ceramic blocks burned at three temperatures with and without the presence of roughcast were used. The ceramic blocks were evaluated by immersion absorption, mechanical strength, and sorptivity tests. Three traces of mortar were used, characterized by water retention and mechanical resistance tests, in addition to adherence with the ceramic block. The adherence results between the materials indicated that the sorptivity influences the adherence with different behaviors, depending on the mortar used.

Resumo O presente estudo teve como objetivo avaliar os potenciais impactos ambientais de diferentes traços de argamassas (chapisco e camada única) e combinações normalmente utilizadas nas edificações brasileiras. Foram avaliados dois tipos de processo executivo para o chapisco (convencional e rolado) e para a camada única (convencional e projetado). Foi utilizada a metodologia de Avaliação do Ciclo de Vida (ACV) com o escopo fabricação das matérias-primas, transporte, execução, destinação final das perdas e carbonatação do revestimento. O processo executivo, principalmente em termos de consumo de material, mostrou ser o fator mais importante para a mitigação dos impactos ambientais dos revestimentos argamassados. Foi verificado que é possível reduzir de 15% a 64% de impactos ambientais do revestimento somente pela escolha da técnica de execução. O estudo tem como principal contribuição a proposição de diretrizes ambientais, com base em uma análise quantitativa, para a especificação e a execução de revestimentos argamassados no Brasil. Abstract This study aimed to evaluate the environmental impacts of different mortar mixtures (roughcast and rendering) and their combinations, commonly used in the Brazilian buildings. Two types of construction process were evaluated for the roughcast (conventional and rolled processes) and for the rendering (conventional and projected processes). We used the Life Cycle Assessment (LCA) methodology considering the scope with the following stages: raw materials manufacturing, transport to the site, construction, end-of-life of the wastes generated during the process and the coating carbonation. We verified that it is feasible to reduce from 15% to 64% of environmental impacts of the coating only by choosing the construction technique. The main contribution of this study is the proposition of environmental guidelines, based on a quantitative analysis, for the specification and construction of mortar coatings in Brazil.

Buildings frequently suffer from the low durability of external coating layers that use mortar. Low durability can be caused by a low efficiency of the adhesion between the coating mortar and the substrate, which may be ceramic, concrete, natural stone or other material. The application of the roughcast is often used empirically to increase adhesion, however, there are few studies to support this practice. The objective of this study was to analyze the adhesion mechanisms between the substrate and the mortar layer, evaluating tensile bond strength implications beyond the microstructure in the transition zone. Two conventional mortar coatings were used, applied on two ceramic substrates fired at 700 °C and 950 °C, besides the application or not of the intermediate adhesion system (roughcast). Both mortars and ceramic blocks were characterized according to the main testing standards. The tensile bond strength was performed for all the combinations proposed. The heat of hydration of samples of the roughcast was also analyzed. The results indicated that the adoption of the intermediary adhesion mechanisms between the ceramic substrate and the mortar, referred to as “Roughcast”, significantly increased the tensile bond strength and altered the type of rupture in the test. The composition of the mortar as well as the firing temperature of the ceramic substrate also influenced the strength conditions.

Shrinkage cavity and shrinkage porosity, often occurring during the production of heavy v-belt pulley roughcast, may lead to the decrease of the pulley performance and further result in casting rejection. Therefore, it is necessary to study the causes and prevention measures of shrinkage defects of the casting. The material of V-belt pulley roughcast at issue is HT250 and it adopts resin sand casting process. With a large amount of practice in workshop and times of revision of the design of foundry technology, we have found that the shrinkage in the hot spot of heavy v-belt pulley roughcast can be reduced or even eliminated to fully meet the performance requirements with a moderate control of pouring temperature and speed, an optimized design of foundry technology, and a strict limitation of chemical composition. This finding will bring illumination to the production process of other heavy pulley roughcast.

Ceramics is one of the oldest artificial materials in the world. As a key process of ceramics manufacture, the sintering process, which belongs to the heat engineering technology, can directly influence the quality, yield and cost of ceramic products. Based on the computer, simulation and artificial intelligence technology, the intelligent ceramics sintering can be realized with the research of CAS (Computer-Aided Sintering). CAS technology is a development tendency of the ceramics manufacture combined with heat engineering technology, because with it not only the sintering quality and yield of ceramics products can be improved but also the energy consume can be decreased. Associated with the application of simulation technology, the topics about CAS are discussed as follows: Basic concept of CAS Method of search for geometric heat centroidal point (GHCP) using of simulation technology Simulation temperature field evolution of ceramics body adopting ANN (Artificial Neural Network) technology Simulative analysis about stress filed of ceramics body Appropriate processes of ceramics sintering based simulation technology The ceramic is widely adopted due to its unique and excellent characters. The requirement of the sintering product quality is very high because of its difficult-to-cut character. The factors which influence the quality of the sintering product include not only the roughcast but also the change event of the temperature distribution in roughcast. From another point of view, the factors include the sintering curve. The traditional sintering curve was defined all by the people’s experience. The waste of resource is not obvious when the small ceramic product is developed by experimentation. However, the large structure parts like missile spinner fail to sinter once, a huge economic loss will come to being. And from the view of environmental protection and the resources reasonable use, this traditional method is also unsuitable for present industrial development. So, in order to set the sintering curve scientifically, the change event of the temperature distribution in roughcast should be studied and the rule has to be found out (Zeng & Zhang, 1994; Zhao, 1993; Jeong & Auh, 2000). This paper mainly introduces CAS, researches for GHCP on simple shape ceramic

Methods and steps of the process planning design were introduced by throttle valve parts. Technical requirements were determined and various parts of the stock allowance of roughcast were confirmed by process analysis of the parts, machining process route was finished completely. Theory was ready for the subsequent actual machining.

With widely use of aluminum alloy in the cares and other industry fields and the like, the aluminum alloy workpieces are becoming the important components, such as load bearing and so on, in which it has been gradually paid attention to the formation and the producing roughcast of shaft forging part of aluminum alloy. the process of across wedge rolling for wrought aluminum alloy has gradually taken notice of improving production rate and saving metal in this field because of its advantages and superiorities. It is very necessary to research and analyze the flow regularity and forming characteristic of aluminum alloy. In this paper, the forming process of cross wedge rolling for wrought aluminum alloy is simulated with Deform 6.0 soft. Thus, it is analyzed that features about cross wedge rolling for aluminum alloy and changeable characteristic of stress in the central axis and changeable regular of effective stress in wedging stage and stretching stage . At the same time, it is researched that the flow characteristic of aluminum alloy from outer layer to central axis. The results as following: in the forming process of cross wedge rolling for aluminum alloy, the central portion of workpiece is applied by two pairs of tensile stress and one pair of compression stress. The flowing velocity of aluminum alloy is gradually reducing from outer layer to center portion along workpiece’s axis. Keywords: Cross Wedge Rolling, Wrought Aluminum alloy, Stress, Numerical simulation

In this paper, we introduce the squeeze casting process to produce flange. This article also introduces the optimized roughcast of flange, the cruces of the die design, the main structure parameters and the working traits of the die. The result shows that using squeeze casting method to produce flange not only can get the qualified part, which also greatly increase the material utilization together with enormously save processing time and processing costs at the same time.

Aimed at the work condition and structure's characteristics of a large discharge emulsification pump's crankshaft, the load type of a low rotational speed and high load were determined, and the quality of a crankshaft is related with material, manufacture, heat treatment and so on. Based on unit production model during the research and development, the processes of the roughcast, manufacture and heat treatment were described: The roughcast was forged by a forging die in order to suffice a low rotational speed and high load. The crankshaft was manufactured by a universal machine tool, clamps and measuring tools in order to obtain the precision of specification after processing. Heat refining after rough cutting, nitrogen treatment and polishing after finish machining were selected in order to improve mechanical property, application life and cost reduction.

Cross wedge rolling valve roughcast is charactered by minor diameter, long stretching and heavy section shrinkage; however, it is hard to select a set of suitable machining process parameter and prone to rolling internal defect. In order to research this problem, a whole forming process of valve roughcast by single cross wedge rolling is simulated with finite element simulation software DEFORM-3D 6.0, which focuses on the stress and strain of the center point of rolled piece under different forming angles. The rolling experiment under different forming angles was done on H500 rolling mill to calculate and analysis of the areas of the centre holes for each rolled piece. The influence of forming angle on internal defect is discovered by a method combining finite element simulation and experiments. At last, it is concluded that forming angle of 28°can improve the internal defect of valve roughcast formed by single cross wedge rolling.

Finite element model was established for the special-section ring rolling. The whole process of ring rolling was simulated based on the DEFORM software. The law that the rolling force is influenced by the idle roll feed speed and main roll rotational speed were found. The results show that the roughcast structure should be similar to finished product structure. IT is significant to optimize roughcast structure and processing parameter, and to improve efficiency of rolling.

Based on the analysis of the preparation of metal rubber (MR) and two pivotal hypotheses, the uniform distribution and the unaltered topological structure of wires in the radial direction of columns in the punch process, a 3D parametrical model was established based on four approaches: helix-making, planar roughcast-weaving, planar roughcast-rolling, and 3D roughcast punching. In the modeling process, 5 lattice types of weave patterns in planar roughcast were put forward, and 10 quantificational modeling parameters were picked up to exclusively define the column MR component structure. The wire distribution was visualized by CAD techniques. The important performance parameter of column MR components (relative density \( \bar \rho \)) can be forecasted by modeling computing, which provides the necessary foundation for the design and optimization of MR materials.

The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that is difficult to machine because of its twisted blades. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. An integrated rough machining course with detailed algorithms is presented in this paper. An algorithm for determining the minimum distance between two surfaces is applied to estimate the tool size. The space between two blades that will be cleared from the roughcast is divided to generate CC points. The tool axis vector is confirmed based on flank milling using a simple method that could eliminate global interference between the tool and the blades. The result proves that the machining methodology presented in this paper is useful and successful.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior A redução de custo tem se tornado cada dia mais uma abordagem com o objetivo de se tonar as empresas mais competitivas. Trabalhos para reduzir os desgastes dos equipamentos no setor sucroalcooleiro tem ido de encontro a essa meta. Este trabalho tem como objetivo estudar a influência de parâmetros de aplicação de chapisco, como velocidade, tensão, corrente, condição de aplicação (seco ou com água), sentido de rotação da moenda, ângulo de aplicação do arame e corrente no rendimento de deposição na utilização do processo “arame tubular auto-protegido”, consumível comumente usados na indústria sucroalcooleira, como metal de adição para aplicação de revestimento duro, em camisas de moendas. O metal utilizado para aplicação deste revestimento é uma liga FeCrC. Em uma primeira fase foram realizados experimentos em laboratório e numa fase posterior foram realizados experimentos em campo, em uma empresa de bens de capital que realiza este serviço. Os resultados obtidos mostraram que a redução da velocidade de aplicação de chapisco reduz as perdas do metal de adição. Outros ensaios com a variação da corrente e tensão, apresentaram redução do rendimento de deposição. Ensaios variando o sentido de giro e ângulo de aplicação não se apresentaram como significativos para influenciar o rendimento de deposição. Por fim, a aplicação a seco, apesar de apresentaram resultados positivos no rendimento de deposição, não foram aprovados no aspecto de qualidade. Cost reduction has become an approach adopted by a growing number of companies aiming to become competitive. Works to reduce the wearing of equipment in the sugarcane sector have met that goal. This work aims to study the influence of parameters such as speed, voltage, current, application in dry and wet conditions, direction, angle and roughcast current in the deposition efficiency in the use of the process “self-protected cored wire”, consumables commonly used in the sugar industry as filler metal for hard coating application in mills shirts. The metal used for the application of the alloy coating was FeCrC. In the first phase, experiments were carried out in a laboratory and, at a later stage, field experiments were conducted in a company of capital goods which performs this service. In a second step, tests were carried out in a company of capital goods which performs this work. The results showed that the reduction of roughcast application rate reduces losses. Further, tests varying current and voltage have showed reduction in deposition efficiency. Tests varying the direction of rotation as well as angle of application have not presented any significant results for deposition efficiency. Finally, both dry and wet application conditions, although tested positive result in the deposition efficiency, have not passed the quality aspect evaluation. Dissertação (Mestrado)

This paper introduces the general requirements of parameter indexes about sphere output mirror with large radius curvature mainly including: sphere radius，spherical area，coaxiality，surface defect disease，RMS value and so on. The difficulties that ultra-smooth machining for sphere output mirror were indicated. A “plano-convex” structure has been designed for transition chip to solving the problem that roughcast and tool pad can’t directly processed by the matrix angles using optical cement method. Based on the sphere output mirror’s process feature, the processing plan to polish sphere surface and then to process platform was laid down. The purpose of this article is to control the test process to get to the target of the “transition chip” method by using “the design and produce of transition chip”，“the conservation of super smooth” and the “control process”, after testing on relative indicators of sphere output mirror, it prove that “transition chip” method can be applied to sipper smooth polish in sphere output mirror with large radius of curvature.

International audience; This study proposes a method to adapt the geometry of the toolpath to a specified target. In the case study presented, the geometrical target is to remove a constant thickness on the rough workpiece. This case is normally present in the polishing of the femoral component of knee prostheses. In fact, an operator carries out these operations manually. The aim of this study is to contribute to the automation of prosthesis production, notably, in the preparation of surface polishing. The proposed method can deform and adapt a toolpath to ensure the required geometry of the machined surface. The proposed toolpath deformation method is composed of three steps: alignment, toolpath deformation, and toolpath smoothing. Alignment between the measured surface of the roughcast prostheses and the nominal toolpath is carried out by an Iterative Closest Point (ICP) algorithm. The principle of this algorithm is to find the optimal rigid transformation to readjust the toolpath on the measured surface. Subsequently , the toolpath is deformed to remove the constant thickness of the roughcast prostheses. Next, to increase the machined quality, a smoothing stage is carried out on the obtained toolpath. Experimental tests on industrial prosthe-ses geometry are conducted to validate the effectiveness of this method.

Combined the roughcast expansion technology for double curvature high rib integral panel part from a certain type of aircraft, a rapid and precise expansion method for the part is realized. The part base expansion method uses geometric simulation modeling method based on the hypothesis of the siding material deformation in thickness direction is negligible and the siding neutral layer surface area is unchanged, and determines reinforced structure and internal milling information on panel body based on mapping theorem and intersection algorithm. Finally, a machine panel as an example, the geometry simulation modeling approach is introduced step by step.

Rough logic and rough sets theory are mainly devoted to analysis of incomplete, uncertain, and inconsistent data. An exploited in the article result of the theory is the so-called rough information system that gives a model for dealing with the situation in which some real objects are represented ambiguously via defined approximation (alternatives of values of the objects attributes). The proposed rough system opens a way to process such information and moreover is equipped with a powerful query language and possibility to classify real objects based on their stored rough characteristics. The implemented RoughCast system and, especially prepared for the case, knowledge base for steel casting defects form such the rough information system. They can be successfully applied in the process of knowledge integration concerning production of steel castings and, in consequence, as a tool in solving technological problems in operating foundries.

International audience; Noisy volumetric details like clouds, grounds, plaster, bark, roughcast, etc. are frequently encountered in nature and bring an important contribution to the realism of outdoor scenes. We introduce a new interactive approach, easing the creation of procedural representations of “stochastic” volumetric details by using a single example photograph. Instead of attempting to reconstruct an accurate geometric representation from the photograph, we use a stochastic multi-scale approach that fits parameters of a multi-layered noise-based 3D deformation model, using a multi-resolution filter banks error metric. Once computed, visually similar details can be applied to arbitrary objects with a high degree of visual realism, since lighting and parallax effects are naturally taken into account. Our approach is inspired by image-based techniques. In practice, the user supplies a photograph of an object covered by noisy details, provides a corresponding coarse approximation of the shape of this object as well as an estimated lighting condition (generally a light source direction). Our system then determines the corresponding noise-based representation as well as some diffuse, ambient, specular and semi-transparency reflectance parameters. The resulting details are fully procedural and, as such, have the advantage of extreme compactness, while they can be infinitely extended without repetition in order to cover huge surfaces.

The Cret-Taconnet residential community in Neuchâtel lies to the south of the station railway yards, on the crest of a slope. It is an ensemble of roughcast covered buildings with traditional vertical windows, all alike; their dimensional profiles play off alignments and forms. Differences of mass extend and emphasise the various scales that coexist at the site. The buildings stand face to face in step-by-step succession up the slope; this last feature accentuates the effects of height or breadth and the sporadic perception of empty spaces between the structures. Three large urban windows pierce through the buildings linking the above-street level to the panoramic views below. This arrangement at once dramatises and reconciles the density of the project — so “typical of the city — and this sight of the distant lakescape and, even further off, of the Alpine skyline.

International audience; Texturing is indispensable for the realistic rendering since it adds surface details that are usually too complex to be modeled directly. Conventional 2D texture mapping remains the most usual approach to texturing, in particular for real-time applications. However, there are some major drawbacks inherent to this approach: the distortion and the discontinuity of textures as well as the lack of the "third" dimension information (geometric effects like roughcast cannot be rendered). 3D texturing has been introduced to computer graphics to resolve these problems. There are two types of 3D texturing: solid texturing that consists of defining color variations through the entire 3D space instead of the 2D one and geometric texturing that consists of adding a "real" third dimension information to surfaces in the form of "real" apparent geometry. This paper presents a detailed survey of 3D texturing. Main principles, advantages, drawbacks and applications are presented. The crucial problem of 3D textures synthesis is studied with a particular attention to analytical methods as well as physical-based models that can provide interesting solutions to this problem.