Search

Background: In patients undergoing surgery for oral cancer, soft support materials are used to minimise trauma to the soft tissues. Silicone-based liners are widely used in prosthetic dentistry. A prerequisite for long-term Adhesion of the liner to the denture base is largely dependent on the surface preparation of the denture material. Objectives: The aim of the present study was to investigate whether surface preparation of the acrylic material by sandblasting increases the adhesion of the silicone support material to the acrylic denture plate. Material and Methods: The study included adhesion testing of four silicone-based soft cushioning materials (Silagum Comfort, Elite Soft Re-lining, Ufi Gel SC, Mucopren Soft) on a total of 270 samples. Each material was tested on 15 samples. Three subgroups with different surfaces were separated: 1 raw—standard surface treatment with a cutter, and 2 sandblasted, with 100 and 350 µm alumina grain at 90°. The samples were subjected to seasoning: 24 h and six weeks. The adhesion force of silicone to acrylic was measured by performing a tensile test using a universal two-column testing machine. Results: The highest bond strength was recorded for Silagum on the surface prepared using 100 µm abrasive and seasoned for 6 weeks (291.5 N). The smallest among the maximum forces was recorded for the Mucopren material (81.1 N). For the Mucopren system with a raw and sand-blasted surface (350 µm), the adhesion strength increased after six weeks. In contrast, the durability of the joint decreased for the 100 µm sandblasted surface. The Elite material exhibited similar values for maximum forces (271.8 N) and minimum forces (21.1 N). The highest strength (226.1 N) was recorded for the sample from the group prepared with 350 µm abrasive and seasoned for 24 h. The lowest value (72.6 N) occurred for the sample from the group with 100 µm abrasive and seasoned for 6 weeks. Conclusions: Sandblasting of acrylic plastic improves adhesion to selected relining silicones. 2. The size of the abrasive employed has an impact on the adhesion between the acrylic plastic and the bedding silicone. 3. In the case of some relining systems (Mucopren), an increase in roughness through sandblasting has the effect of reducing the durability of the bonded joint. [ABSTRACT FROM AUTHOR]

Ni–Cu alloys are a suitable candidate as a catalyst in Hydrogen Evolution Reaction due to their catalytic performance and good stability. To enhance this activity more, the active surface area of the material should be enhanced. It is commonly achieved by the synthesis of metals and alloys in the form of nanostructures. In this work, Ni cones fabricated by the one-step method were applied as a substrate for the deposition of thin Cu layers. Then, these materials were annealed in an ambient atmosphere to obtain Ni–Cu structures. The investigation of changes in morphology and chemical composition, as well as roughness and wettability before and after the annealing process was performed. Moreover, the measurements of catalytic properties were carried out in 1 M NaOH. The values of the Tafel slope and the electrochemical active surface area were studied. The proposed method can be successfully applied to fabricate structures of other alloys for the desired properties. [ABSTRACT FROM AUTHOR]

Broken soft and low permeability (BSLP) coal reservoirs are widely distributed in China. However, due to its soft and broken structure and low permeability, the conventional vertical/horizontal well direct fracturing technology is not ideal for the enhancement of BSLP coal seams and the surface development of coalbed methane (CBM). The efficient development of CBM in BSLP coal reservoirs has been an important technical bottleneck restricting the large-scale development of CBM industry and the efficient treatment of coal mine gas control in China. Based on the systematic analysis of the characteristics of BSLP coal reservoirs and the problems existing in the surface development of CBM, the current technological progress in the enhancement of BSLP coal reservoirs and surface development of CBM were reviewed by taking horizontal well as the base well type and focusing on three different technical directions: indirect fracturing, stress relief and consolidation before fracturing. The CBM development technologies of indirect fracturing, including roof indirect fracturing, gangue indirect fracturing and hard coal stratification indirect fracturing were summarized. The stress release CBM development technologies using different stress release methods, such as hydraulic jet cavitation, gas dynamic cavitation, mechanical + hydraulic + induced instability coupling cavitation and hydraulic slit, were reviewed. Furthermore, the CBM development technology of first consolidation and then fracturing of BSLP coal reservoirs induced by microorganisms was also summarized. The exploration of indirect fracturing technology has accumulated a lot of engineering practice, and has achieved a good effect on enhancing the BSLP coal reservoirs in areas with suitable geological conditions. The exploration of new technology for enhancing BSLP coal reservoir represented by stress release has also made great progress, and has entered the stage of engineering tests and verification. According to the characteristics of BSLP coal reservoir and the new development principle, the horizontal well stress release technology has greater potential for reservoir reconstruction and better effect for CBM development. Based on the horizontal well stress release method, the development trend of BSLP coal reservoir enhancement and surface CBM development technology was forecasted in three aspects: expanding the stress release range, improving the development effect of CBM and achieving the co-production of coal and CBM. It is expected to provide reference for improving the stimulation effect of BSLP coal reservoir and increasing the production of CBM well in China.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background. Osseointegration of medical equipment, including implants, into the bone is one of the main conditions for a successful outcome of surgical treatment. To improve the reliability of the functioning of medical equipment products by improving the osseointegrative properties, the authors have developed a unique technology for developing the surface of the implanted component. Thus, the aim of the work is to develop a technology for developing the surface of medical equipment products based on laser metal foaming. Materials and methods. Experimental studies have shown that the surface geometry and structure of the surface layer after laser foaming meet the requirements for medical equipment products for better osseointegration into the patient's bone. The results were confirmed by optical and electron microscopy data. Results. Studies have shown that the composition of the gaseous medium has the most significant effect on the structure of the surface layer. This factor determines the appearance in the surface layer of a large number of chemical compounds that significantly change the properties of the material. During the experiment, this factor was varied, and the rest were stabilized at a constant level. It has been established that the increase in the chemical inhomogeneity of the surface layer increases significantly with the introduction of air into the composition. When Argon is used as a working medium, the surface structure is normalized to the level of the material base. Conclusions. In the process of work, a developed structure was created on the selected surface area without changing the chemical composition with an increase in the area of osseointegrated structures up to 100 % of the original surface. For processing, it is recommended to use an inert gas medium, and the medium pressure must be above 8 bar. The feed speed of the laser head should be at least 5000 mm/min, but not exceed 10 000 mm/min.

Nickel foam is widely used as a current lead/ current collector and as the base of nickel hydroxide electrodes for hybrid supercapacitors. An investigation of the influence of activation conditions for a commercial sample of nickel foam produced by Linyi Gelon LIB Co Ltd (China) was carried out using the method of impact nickel plating. The morphology of activated and non-activated nickel foam samples was investigated by scanning electron microscopy. Activated and non-activated nickel foam samples were investigated by methods of cyclic voltammetry and galvanostatic charge-discharge cycling in the supercapacitor mode. It was shown that upon activation at i=1 A/dm² and τ=10 min, a thin layer of porous nickel with incomplete coverage was formed. Activation with impact nickel at i=7 A/dm² and τ=3 min revealed the formation of a nickel coating with a highly developed surface, on which local cracks were found as a result of the accumulation of internal stresses. Activation with impact nickel at i=1 A/dm² and τ=10 min led to the formation of a coating with a highly developed surface, with significant peeling of the coating. Cyclic voltammetry showed high efficiency of impact nickel activation at i=7 A/dm², τ=3 min, and i=20 A/dm², τ=5 min. The specific current of the cathode peak increased 6.06–6.44 times with respect to the non-activated sample. The investigation of the activated samples’ electrochemical characteristics by the galvanostatic cycling method showed that impact nickel activation at i=1 A/dm² and τ=10 min was insufficient. It was found that at a discharge up to E=0 V, the maximum specific capacitance of 0.731 F/cm² was obtained for samples activated by impact nickel at i=7 A/dm² and τ=3 min. The increase in specific capacitance compared to the non-activated sample was 4.49 times. At full discharge, the highest electrochemical activity was found for nickel foam samples activated by impact nickel at i=20 A/dm² and τ=5 min. The specific capacitance was 0.505 mA∙h/cm², and it increased 9.02 times. [ABSTRACT FROM AUTHOR]

The study determined the kinetics of the selective anodic dissolution of the copper-zinc intermetallic compound Cu5Zn8 (gamma-phase) in an acetate buffer solution. Microscopic and X-ray analysis methods demonstrated the selective nature of the corrosive dissolution of Cu5Zn8. The dissolution results in the dezincification of the intermetalic compound and morphological development of its surface accompanied by the formation of the copper phase. A theoretical model of the transition of the electrode surface to the critical state together with the experimental concentration dependencies of the critical potential and critical overvoltage demonstrated that the dissolution of zinc from Cu5Zn8 is most probably limited by the non-stationary diffusion mass-transfer in the solid phase of the intermetallic compound. The study also demonstrated that the phase transformation during the overcritical selective anodic dissolution of the gamma-phase of Cu5Zn8 in an acetate environment accelerates following the growth of the anodic potential and is controlled by the surface diffusion of adatoms towards the three-dimensional nucleus of the copper phase with instantaneous nucleation.

The article presents the preparation process of AC-AlSi12 aluminum alloy surface by application of anodic oxidation method. The method enables the formation of a porous oxide layer (Al2O3) which generates the substrate of durable adhesive bond with an epoxy resin. It also presents the influence of the form of silicon precipitates in the modified alloy upon anodizing process, uniform structure and thickness of the oxide layer as well as the topography of its surface which is expected to improve adhesion of the resin and silumin. The paper describes how the position of oxidized surface against the negative electrode influences the coating structure. The studied silumins are intended to form the material for casting of 3 dimensional objects whose parts will change the distribution of electric field strength that may cause non-uniform structure of the coating.

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is important nowadays to underline some relevant topics concerning the effective contribution of 3D high detailed products derived from innovation and integration of Geomatics technologies, allowing a remarkable development in descriptive metric capabilities, supporting and improving the material recording, representation, analysis and characterization about alteration of the constructive systems. Considering the relevance of the complex interdisciplinary research of these issues that move around the Cultural Heritage safeguard and due to its extreme vulnerability, these models must give a response to different problems. Primarily they has to provide complete models on which to pursue accurate morpho-dimensional documentation, and to base structural assessment, decay investigations, and consequently to underpin restoration practices and support operational workflow in CH assets monitoring. Some peculiarities of new methods for semiautomatic processing algorithms are thus evidenced, advantaging their proficiency to behave as tools for a more sustainable approach in the general process of preservation and protection. Specifically about the ancient masonries documentation, the chance of using digital products derived from very high scale models, as the detailed orthoimages projection and surfaces development offers many opportunities. Here, a late-medieval stratified dovecote tower in Verolengo (TO) with a particular trunk-conical shape had been analysed in order to reconstruct an identity and a historical and architectural framework, de facto not recognized yet. A 3D reconstruction by dense matching techniques will be presented, in the complex context that are the vertical high buildings, presenting one of the highest level of vulnerability. The importance of the 3D model availability, closely connected to dense radiometric information, has been particularly expressed in two main direction for the diagnosis both of volumetric structure assessment and the material characterization of the mixed masonries walls. [ABSTRACT FROM AUTHOR]

The intersection of two surfaces is a common line to both surfaces. This line is often called transition line. The authors propose an analytical and a computer graphics intersection between two perpendicular axes cylinders. The analytical expression of such intersection will be obtained and transposed on the development of one cylinder. The distance between the two cylinders axes is essential in the aspect of the transition line. This transition line can be also obtained, using the computer, by the MathCAD programme. Some samples are relevant in this subject, according to the distance between the cylinders.

In order to create a perspective drawing on a curved surface, the quadraturista had to face, in addition to the flat perspective drawing issues, also the ones related to the mapping of the three dimensional surface. In literature we can find two methodologically different approaches related to the flat design transposition procedures onto the curved surface: indirect and direct method. The indirect one, partially described by Vignola, is based on the use of pre-designed cartoons on the ground. The direct one, described by Andrea Pozzo, is based on the direct projection of a flat grid onto the curved surface. Both the ceiling painting of the Church of San Matteo in Pisa and the parietal one of the Church of S. Caterina in Livorno show, even if observed from the privileged viewpoints, some irregularities. These irregularities, as we are going to show, are actually the consequences of the method applied for the transposition of the flat drawings onto the curved surfaces. [ABSTRACT FROM AUTHOR]

Surface development origins from the cloth-making and computer graphics without consideration of the thickness, involving nonlinear optimization and constraints. Moreover the research of surface development mainly focuses on the planar development. In this paper, the development of the non-developable sheet to planar, singly-curved and doubly-curved surface patterns is investigated. An optimal developing algorithm is formulated to minimize the strain energy required for the deformation of the sheet, in which an orthogonal curvilinear coordinate system is used for three target patterns to simplify the constraints for the developing process, resulting in an unconstrained quadratic optimization. Both shell element and solid element are utilized in the finite element analysis. Similar developed results are obtained for planar and spherical patterns by using these two types of elements. But for the cylindrical pattern, the solid element model gives more accurate result due to no contribution of the shell element to the translation of the rotational freedom. [ABSTRACT FROM AUTHOR]

The intersection of two surfaces is a common line to both surfaces. This line is often called transition line. The authors propose an analytical and a computer graphics intersection between two perpendicular axes cylinders. The analytical expression of such intersection will be obtained and transposed on the development of one cylinder. The distance between the two cylinders axes is essential in the aspect of the transition line. This transition line can be also obtained, using the computer, by the MathCAD programme. Some samples are relevant in this subject, according to the distance between the cylinders. [ABSTRACT FROM AUTHOR]

A detailed analysis of potential changes on galvanostatic charge/discharge curves for LaNi 4.5 Co 0.5 Sn 0.1 powder-composite electrode has been carried out with regard to material surface development as a result of hydrogenation. It has been shown that the efficient surface of the electrode increases mainly during its cathodic charging. The surface development caused by hydrogen desorption is evident for the first cycle only. Electrode cycling is prone to continuous surface development which is especially distinct for some first cycles. [ABSTRACT FROM AUTHOR]

Highlights: [•] New trends in chemosensing using molecularly imprinted polymers (MIPs). [•] Importance of the control over the ratio of surface area to volume. [•] Preparation of MIPs with the high (surface area)-to-volume ratio. [•] Analytical parameters of MIP chemosensors. [ABSTRACT FROM AUTHOR]

In this paper, a simple sol-gel route has been adopted in developing substrate surface for the first time. Only by adjusting the concentration of precursor solution, LaAlO (LAO) nanodot arrays were directly obtained on LAO single crystal substrate, without incorporating additional processing steps. Subsequently, YBaCuO (YBCO) superconducting films were prepared on the nanodot arrays using a low-fluorine solution process. In contrast, J of YBCO films grown on the substrate developed with nanodot arrays is almost three times as large as that of YBCO films grown on undeveloped substrate in an applied magnetic field with the strength of 3 Tesla. The pinning force density ( F) of YBCO film on the nanodot arrays developed substrate is 2.7 GN/m which exceeds that (1.8 GN/m) of YBCO films on undeveloped substrate. The results of cross-section transmission electron microscope (TEM) images show that the extended defects along the a- b planes of YBCO, induced by the developed substrate with nanodot arrays, should be the origin of the J enhancement. [ABSTRACT FROM AUTHOR]

Abstract: This paper, starting with the existence of general introduction of associated coal bed methane (CBM) with coal, expatiates in five parts on the transfer rules of CBM changing with time in three-dimensional rock space of the coal mine under the effect of mining activity and ventilation; On the basis above, the principle having been validated in practice is also pointed out for us to follow in methane extraction from coal mines. Finally, it draw conclusion that mining areas with high gas concentration(including coal and gas outburst), low permeability, and composite coal seams can realize the coal mine methane (CMM) extraction and ground development in a high efficient way as long as we follow the miming activities and the gas migration rules under the effect of negative pressure ventilation. [Copyright &y& Elsevier]

This paper presents a method for deforming a surface model using guide surfaces. Two guide surfaces are given as references on which the surface model lies before and after deformation. The proposed method consists of two steps: surface development and model deformation. The surface development first constructs a one-to-one mapping between two guide surfaces and yields displacement constraints. Displacement constraints are then used to create a smooth 3D vector field, a deformation function for model deformation which maps an arbitrary point on the original model onto the corresponding point on the deformed model. The proposed method, implemented as a module of the shoe design system in C++ and Unigraphics using UG/Open, can also be applied to a variety of design problems (e.g., clothing). [ABSTRACT FROM AUTHOR]

This paper introduces simplified algorithms for predicting sheet configurations in panel forming production. Panel geometries are described using Non-Uniform Rational B-Splines technique. The blank design algorithms work conveniently in a non-dimensional parametric system. Two effective blank design approaches have been adopted and developed. The first method involves a simple geometric mapping based on the deformation compatibility condition, and the second approach performs minimization on the most-like even deformation corresponding to the lowest deformation energy, which, in an ideal situation, approaches well practical deformation path. Numerical applications show that combined use of these two methods allows to develop complex geometry in a low cost. [ABSTRACT FROM AUTHOR]

Abstract: This paper introduces a simplified algorithm for generating planar developments of arbitrarily three-dimensional (3D) surface. The 3D surface is first divided into triangular finite elements, the deformation from the curved surface to its planar development is then modeled by in-plane strains of elemental edges. The developed planar shape corresponding to minimum deformation nonuniformity and volume constancy is obtained by solving a constrained nonlinear programming problem. A multi-step scheme of the algorithm is presented and applied to the blank design of sheet metal parts. Based on the assumption that the thickness strain is one of the principal strains, the deformations from the final part to its initial blank are estimated. Numerical and experimental results as well as application examples demonstrate that the present algorithm can predict the blank shape of 3D sheet metal part within a small range of error with low computing time. [Copyright &y& Elsevier]

Abstract: A new blank design method is proposed based on iterative FE sheet metal forming simulations. An algorithm is introduced to approximately develop both CAD design and FE-virtually formed sheet metal parts onto a 2D plane. The errors between the original CAD design and the FE simulated parts can be characterised in both 2D and 3D spaces. An integrated numerical procedure for the netshape sheet metal forming process is detailed in the paper and a U-type channel part is taken as an example in the investigation. [Copyright &y& Elsevier]

Surfaces of many engineering structures, especially those of ships and airplanes, are commonly fabricated as either single- or double-curved surfaces to meet functional requirements. The first step in the fabrication process of a three-dimensional design surface is unfolding or flattening the surface, otherwise known as planar development, so that manufacturers can determine the initial shape of the flat plate. Also a good planar development enables the manufacturer to estimate the strain distribution required to form the design shape. In this paper, an algorithm for optimal approximated development of a general curved surface, including both single- and double-curved surfaces, is established by minimizing the strain energy of deformation from its planar development to the design surface. The unfolding process is formulated into a constrained nonlinear programming problem, based on the deformation theory and finite element. Constraints are subjected to the characteristics of the fabrication method. Some typical surfaces, such as convex-, saddle-, and cylinder-type ones, as well as the surfaces of practical ships are unfolded using the proposed algorithm and the results show the effectiveness of this algorithm. [ABSTRACT FROM AUTHOR]

The fit of garments is an important issue that concerns manufacturers, retailers and consumers with two contributory factors. One is the lack of information and standardisation in relation to the shape of the human body. The other is the craft and skill-based nature of the pattern technology function as performed in most garment manufacturers. Recent advances in body scanning technology are enabling vast amounts of data to be collected for monitoring the demographic variations in the shape of the human body. In addition, commercial software is now available to generate 3D garment specifications. However, one important function to date has not received significant attention. This is the area of generating 2D patterns from 3D design and body shape information. This paper describes work on an algorithm that attempts to generate an optimum pattern while taking into account (i) body shape data, (ii) 3D garment design data, (iii) fabric characteristics, and (iv) tailoring mechanisms for improving fit (dart and gussets) The strategy adopted in this work is to formulate an optimisation function based on flattening energy. Here, flattening energy is defined as that energy required In distorting the fabric of the 2D pattern so that it takes up a specified 3D shape. The fabric behaviour is characterised by a woven structure and the 3D shape is specified in terms of a triangulated surface. Strain constants describe the force versus strain response of the fabric for the weft and warp directions and shear. By analysing the change in geometry of individual surface triangles during the flattening process, the individual strains are evaluated. These are then converted to energy values and summed over all the triangles comprising the complete surface. Tests were conducted by designing panels with different dart configurations on a classical shape (i.e. a torus) covering both hyperbolic and elliptical curvature regions. This was then extended to a size 12 lady's mannequin. Finally, 2D flattened patterns for garment panels with different dart configurations were generated and made-up for a specific fabric. The garment was then put on the actual mannequin and the degree of fit assessed. [ABSTRACT FROM AUTHOR]

In this paper the principle for developing 3D mesh of flat triangles on arbitrary surfaces to its closest flattened 2D mesh is proposed. Such principle is proved equivalent to the condition that the finite element method (FEM) residual forces of the 2D-mesh member structure are equal to zero. The incremental FEM method and iterative procedures are derived for eliminating such residual forces. For developable 3D mesh of flat triangles, the method of this paper will give the accurate flattened 2D mesh, and for non-developable 3D mesh, this paper can lead to the closest flattened 2D mesh. The obtained 2D mesh can also be taken as the flattened form of the curved surface, which is described by the 3D mesh of flat triangles. Numerical examples show that the method of this paper has stable convergence and high efficiency. [Copyright &y& Elsevier]

The creation of acrylic dentures involves many stages. One of them is to prepare the surfaces of artificial teeth for connection with the denture plates. The teeth could be rubbed with a chemical reagent, the surface could be developed, or retention hooks could be created. Preparation of the surface is used to improve the bond between the teeth and the plate. Choosing the right combination affects the length of denture use. This work focuses on a numerical analysis of grooving. The purpose of this article is to select the shape and size of the grooves that would most affect the quality of the bond strength. Two types of grooves in different dimensional configurations were analyzed. The variables were groove depth and width, and the distance between the grooves. Finally, 24 configurations were obtained. Models were analyzed in terms of their angular position to the loading force. Finite element method (FEM) analysis was performed on the 3D geometry created, which consisted of two polymer bodies under the shear process. The smallest values of the stresses and strains were characterized by a sample with parallel grooves with the grooving dimensions width 0.20 mm, thickness 0.10 mm, and distance between the grooves 5.00 mm, placed at an angle of 90°. The best dimensions from the parallel (III) and cross (#) grooves were compared experimentally. Specimens with grooving III were not damaged in the shear test. The research shows that the shape of the groove affects the distribution of stresses and strains. Combining the selected method with an adequately selected chemical reagent can significantly increase the strength of the connection. [ABSTRACT FROM AUTHOR]