Texturing Process Research Articles

Physicochemical Properties of Sago Starch Fractionated by Butanol

AbstractAmylose is one of the sago starch constituents which plays an important role in the processes of gelatinization, retrogradation, and the pasting process of starch texture. By separating amylose from amylopectin through a fractionation process, high‐content amylose can be obtained. In this study, the process of fractionating sago starch is carried out using hot water and the addition of n‐butanol dropwise with certain time variations (1, 2, 3, 4, and 5 h). The precipitate formed, which is the fractionated sago starch, is separated from the n‐butanol fraction using centrifugation. The physicochemical properties of fractionated sago starch are characterized in terms of chemical change using Fourier transform infrared (FTIR), molecular weight using gel permeation chromatography (GPC), particle size, morphology, amylose content, crystallinity, water‐solubility, swelling power, moisture, ash content, thermal stability using differential scanning calorimetry (DSC), crystallinity using X‐ray diffraction (XRD), and morphology using field emission scanning electron microscopy (FESEM). The results show that the fractionation process using n‐butanol increases the particle size, amylose content, and thermal stability compared to the native sago. The crystallinity, water solubility, and swelling power of the fractionated‐sago starches are decreased. The highest amylose content and gelatinization temperature properties are achieved by the addition of n‐butanol for 4 h.

3D Modeling of a Virtual Built Environment Using Digital Tools: Kilburun Fortress Case Study

The reliable reconstruction of cultural or historical heritage objects is an urgent problem for humanity. It can be successfully solved using up-to-date 3D modeling tools. The proposed technique allows for modeling virtual environments at an even higher level. This study aimed to develop an approach for designing historical heritage objects with sufficient accuracy using a built environment. The Kilburun Fortress was chosen as the object of study. The modeling procedure includes monitoring the object’s territory, analyzing archival, librarian, and cartographic sources, and further modeling and reproducing the research object in a virtual environment using various software tools. The following stages were implemented during this study: analysis and processing of preliminary data (analysis of plans and schemes, overlapping maps); the scaling of graphical objects for the reliable reproduction of the studied object; the design of a working 3D model using AutoCAD and SketchUp; the rendering and final processing of textures using Quixel; and visualization using Twinmotion. As a result, a model of the historical heritage object was created using 3D means. The model can also be integrated into ArchiCAD and Revit software.

High-efficient laser-based bionic surface structuring for enhanced surface functionalization and self-cleaning effect

In this work, a laser-based surface functionalization method combining laser surface texturing and silicone oil-assisted heat treatment was developed to fabricate superhydrophobic surface. Two bionic surface patterns, i.e., duck feather pattern and shark skin pattern were designed and fabricated using different laser processing parameters. 3-D digital microscope, scanning electron microscope, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were utilized to analyze the surface morphology and chemistry of the laser functionalized surface. Self-cleaning test was conducted to compare the dust removal ability between the untreated surface and laser functionalized surface. The rough hierarchical surface structure was induced by laser texturing process, and the heat treatment process with silicone oil led to the formation of low surface energy. With the combined effects of surface structure and chemistry, the fabricated surface exhibits superior superhydrophobicity. Moreover, the laser functionalized superhydrophobic surface exhibits good self-cleaning ability, and highly efficient dust removal process was observed owing to the bouncing removal of water droplets. This work is not only simple and convenient, but also significantly reduces the production cost and enhances time efficiency for fabrication of superhydrophobic surface, and thus shows strong potential for applications in diverse areas.

Effect of laser texturing bulges on tribological properties of 316L stainless steel

The laser surface texture process will inevitably produce the edge of material surface texture bulges. Currently, laser processing bulges are generally polished directly, but this method ignores its impact on the friction pairs. In this paper, the tribological properties of polished and unpolished textured surfaces were investigated under dry friction, oil lubrication, and seawater lubrication conditions using three shapes of texture (grooves, square pits, and round pits) prepared on the surface of 316L stainless steel. The results show that the polished surface of 316L stainless steel texture increases wears, and the friction mechanism is mainly adhesive wear, while the unpolished surface of the texture has less wear, and the friction mechanism is mainly abrasive wear. The method and principle of using machining bulges to improve the wear resistance of friction pairs are discussed to address the differences in the tribological performance of entire friction pairs due to the influence of machining bulges of different shapes of texture.

Study of the correlation between the surface roughness and the characteristic of the acoustic signal from laser texturing process

Growing attention to the laser texturing technology from various industries lately lead to the collective number of studies related to the process optimization. However, in the application related to the process of turning metallic surface into hydrophobic characteristic, process optimization is not the only factor of the quality assurance of the laser-textured surface. The application of real-time monitoring was found to be significant factor to aid in obtaining the desired quality. This paper present the study of the correlation between the surface roughness of the laser-textured surface and the characteristic of sound signal acquired from the process in order to evaluate the feasibility of this signal to monitor the process by a real-time basis. To achieve the goal of the study, laser texturing process had been done on the 316L stainless steel with the different set of peak power and scanning speed. The sound signal was captured between 20 Hz to 20 kHz during the process. The analysis results show that the sound signal recorded the larger amplitude and root means square (RMS) with the increment of laser peak power, and declining scanning speed. This trend show that the RMS of sound increase as the roughness of the textured surface increase. The overall results trend show that the characteristic of sound signal could give the significant information related to the roughness of the textured surface which were produced from different laser parameters. Thus, with further advancement, acoustic method could possibly be used as the real-time monitoring system for a laser texturing process.

The Transformation Of Traditional Food as A Tourist Attraction to Visit Silalahi II Tourism Village, Dairi Regency

Silalahi II Tourism Village, Dairi Regency has great potential in food tourism (culinary tourism) because it has cultural wealth from a very heterogeneous community as residents of the Dairi Regency area, as well as assimilated remains the culture of the past community, each of which has its own special culinary. This study aims to identify culinary tourism in terms of: (1) the variety of menus offered (2) the process of transforming traditional foods and (3) tourists' perceptions of traditional foods. Data collection techniques include observation, questionnaires, interviews and documentation. The transformation process such as shape, texture, color, taste, processing and presentation method as well as sanitation hygiene. Presentation of results described qualitatively and quantitatively. Based on the results of the discussion that the menu offered has varied but the placement of the menu has not followed the order of international gastronomy and the service techniques used. The transformation process includes the processing of spices, equipment, texture, taste and presentation. Tourists' perceptions of traditional food offered are generally satisfied by 52% of 100 respondents. The suggestion from this research is the need for training, coaching and empowerment of restaurant managers or the general public related to factors of cleanliness, neatness and politeness of waiters to standardize taste and presentation.

Tribological Properties of Ti6Al4V Alloy Composite Texture Fabricated by Ultrasonic Strengthening Grinding and Laser Processing

The Ti6Al4V alloy has been widely used in aerospace equipment and medical devices. However, the poor wear resistance of the Ti6Al4V alloy hinders its further engineering application. In this study, the ultrasonic strengthening grinding process (USGP) and laser texturing process were employed to enhance the wear resistance of Ti6Al4V alloy. The frictional behavior of all samples was determined via a ball-on-disc friction and wear tester under dry conditions. The worn surface morphology, cross-sectional hardness, surface roughness, and microstructure were analyzed. The results demonstrated that the USGP induced high hardness, high dislocation density, and grain refinement, as well as improvements in the wear resistance of Ti6Al4V. Moreover, laser texture could enhance the capacity to capture wear debris and reduce wear probability. When combining the USGP and laser texturing process for the surface treatment of Ti6Al4V alloy, the lowest and most stable friction coefficients were obtained, as well as the best wear resistance. Compared to the polished sample, the steady stage friction coefficient of the sample treated by USGP and laser texturing process was remarkably decreased by 58%. This work demonstrates that combining the USGP and laser texturing process could be a promising solution for improving the wear resistance properties of Ti6Al4V alloy, which makes it more suitable for various engineering applications.

Theoretical and numerical investigation of micro-textures fabrication by ultrasonic surface rolling process

Surface texturing is a potential approach to achieving excellent surface performance. To realize high precision and efficiency in micro-texturing fabrication, a surface texturing method utilizing an ultrasonic surface rolling process is proposed. Firstly, the feasibility and geometric controllability of micro-texture preparation using ultrasonic surface rolling process are analyzed. Then, a contact theory model of ultrasonic rolling texturing process is established, which can describe the geometric relationship of the micro-texturing generation region. Based on the elastic–plastic theory, simulations of single-pass and multi-pass ultrasonic rolling texturing processes are developed to elucidate the formation and strengthening mechanism of micro-textures, and further characterize the effects of ultrasonic rolling machining parameters on micro-textures. A series of validation tests of ultrasonic rolling texturing are implemented on AISI 5140 steel. Simulation and experimental results show that the ultrasonic surface rolling process can fabricate micro-groove arrays with the periodic distribution. The validity of the theoretical and finite element models is confirmed by the comparison results. It is demonstrated that the ultrasonic rolling texturing process is a feasible and efficient way to fabricate controllable micro-textures.

Phase transformation pre-treatment of diamond wire-sawn multi-crystalline silicon wafers for metal-assisted chemical etching of solar cells

Phase transformation by the heat treatment, prior to metal-assisted chemical etching (MACE) of solar cells, has been proposed and studied, as a pre-treatment approach for diamond wire sawn (DWS) Si wafers. The results of the study show that the phase transformation pre-treatment can modify the microstructure of amorphous Si surface layers of DWS multi-crystalline (mc) Si wafers. The modified surface layer proved to be more reactive to the chemical etching solution, which was the primary factor for the improvement in the treated solar cells. A significant improvement on the surface uniformity and morphology of the textured Si wafer was achieved, subsequent to the pre-treatment, during the MACE texturization process. These solar cells based on the treated DWS mc-Si wafers displayed a gain of about 0.18% (absolute value), in the overall photoelectric conversion efficiency (η), when compared to the solar cells of the same batch, for the untreated wafers, on the same production line. It is hence, proven that this pre-treatment method, when used as a supplementary technique to the wet-chemical texturization process, has great potential as an effective application technology for solar cells based on DWS mc-Si wafers.

Task-dependent contribution of higher-order statistics to natural texture processing

Task-dependent contribution of higher-order statistics to natural texture processing

Laser surface texturing under transformer oil conditions for improved process quality and tribological behaviors

Among various surface modification technologies, laser surface texturing (LST) to introduce texture has attracted more scholars' attention for controlling the tribological performance. The enhanced processing quality of the textured surface results in reducing the coefficient of friction and improving the wear resistance. In this study, dielectric transformer oil was used to protect the surface of GCr15 bearing steel from undesired gases in the atmosphere during the laser processing. Three types of dimples, including circle, rectangle and hexagon, were ablated to evaluate their influence on friction and wear. It was found that LST with transformer oil greatly improved the surface texture processing quality, where the edges of dimples were effectively designed and burrs-free. Results showed that the depth of dimples was reduced up to 7%. Compared to the samples fabricated in air, the friction coefficient and the wear of improved surface were reduced up to 55% and 73.8%, respectively. This was attributed to the excellent shielding and coolant property of transformer oil. Additionally, the shapes of the dimples, the applied force and the sliding speed significantly affected the friction coefficient, where dimples operate as lubricant and debris stores. This study provides certain feasibility guidance for the tribological modification of GCr15 bearing material with oil method and expands its application on engineering surfaces.

The cleanability of laser etched surfaces with repeated fouling using Staphylococcus aureus and milk

Biofouling is a serious problem in the food industry, and one way to control biofouling is using topographically patterned surfaces. This in vitro study used a laser surface texturing process to produce six differently patterned topographies which were analysed for their topography and wettability with repeated fouling and cleaning. The surfaces were spray-inoculated with Staphylococcus aureus suspended in either sterile distilled water or whole milk, then spray-cleaned using a chlorinated, alkaline cleaner. The surfaces were cleaned up to 20 times and analysed for changes in their surface properties and biofouling. Analysis of Variance was used to assess the effect of the main factors and two-way interactions. Principal component analysis was used to discern underlying relationships. There were no significant differences (T-Tests) in the overall level of biofouling between the different rippled sub-textures. The spiked surfaces showed no overall increase in biofouling and the number of cleans but were predominantly influenced by the texture sub-type. The less regular spiked surfaces within the medium range showed the lowest levels of biofouling, even with repeated cleaning. This study demonstrated that the use of such surfaces in in vitro studies may reduce biofouling, but particular attention needs to be given to the surface design.

Novel chemical texturizing process in Boron–doped As-cut multi-crystalline silicon wafer for increasing the optical properties

The aim of this paper, the improvement of optical properties of as-cut boron doped p-type multi-crystalline silicon (mc-Silicon) wafer grains obtained by chemical texturization is presented. mc-Silicon wafer gives lower reflectance is one of the important parameters for improving solar cell efficiency and it can be obtained by the optimized texturizing conditions. In this work, we have carried out different types of chemical etchants in the same ratios for the texturizing process. Here, we have carried out HF + HNO3 + KMnO4 = 2.5:1:0.2M (set-1), HF + HNO3 + K2Cr2O7 = 2.5:1:0.2 M (set-2) and HF + HNO3 + IPA =2.5:1:0.2M (set-3) for the individual etchant etching time duration is 2 minutes, 5 minutes and 7 minutes. The mc-Silicon wafer grains were analyzed by the optical microscope, UV- visible, X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Thickness profilometer, and Fourier transforms infrared (FTIR) spectroscopy for before and after texturizing. The set-1 with a 2-minutes etched wafer gives better results as the lower reflectivity value is below 12.5%, lower surface roughness, lower oxidation, and better surface contained.The same orientation of the grains were used as indicated by XRD results. The sheet resistance of the mc-Silicon wafer grains were calculated by the four-probe method.

Underwater laser texturing for enhanced adhesive joint bonding strength of Al-Mg alloy

In this research work, nanosecond pulsed fiber laser texturing was performed on Aluminum-Mg alloy (AA5754). Effect of laser texturing as a surface pre-treatment method in adhesive bonding process was investigated in details. Laser texturing was performed in under open air condition, under static water condition and under flowing water conditions. Grid shaped textures were fabricated on Al-Mg alloy work-pieces. The geometrical parameters of grid texturing were varied at two levels. Pitch of the lines were kept at 300 and 400 μm in both horizontal as well as vertical directions. Scanning speed of laser texturing process was also varied at two levels that is 2.5 and 5 mm/s. Total four experiments were conducted in each atmospheric conditions. Surface roughness and water contact angle of each surface was evaluated. Surfaces were also characterized using scanning electron microscope. Lap shear strength of each samples were evaluated using a universal tensile testing machine (UTM). Failed surfaces were analyzed to investigate the mode of failure. It was observed that the textures created in flowing water conditions resulted in cohesive mode of failure while samples fabricated in open air and in under static water conditions failed in adhesive and mixed mode respectively. Samples prepared in flowing water conditions resulted in higher lap shear strengths compared to static water, open air, and plain surfaces.

Sensory Texture and Mastication Physics of Multi-Phase Meat Products

Food products often consist of several phases. Comminuted meat products, for example, are multiphase systems consisting of structured meat particles and unstructured batter-like substance. To develop and understand the processing of these products, it is important to understand the sensory and mechanical perception principles. To this end, two-phase food prototypes consisting of mixtures of ground beef and beef batter were prepared and subjected to sensory, texture, and oral processing analysis. The oral processing analysis focused on the biomechanical data of the chewing process, namely the kinematics of jaw movement and electromyographic activity. The ground meat served as the anisotropic phase and the meat dough as the isotropic phase. A significant increase in muscle activity, duration per bite, and occlusion time with increasing proportion of fibrous particles was demonstrated (p < 0.05). In contrast, a higher proportion of isotropic substance resulted in significantly higher amplitudes of jaw movement and faster jaw kinetics (p < 0.05). In mixed regimes, the system responded mainly according to the dominant phase, with sensory or mechanical response changing at a critical point. In combination with texture and sensory data, a holistic characterization of the food models could be performed.

Effect of textures fabricated by ultrasonic surface rolling on dry friction and wear properties of GCr15 steel

Linear textures and cross textures with different processing stepovers were fabricated on the surface of GCr15 steel by ultrasonic surface rolling processing (USRP). The effects of texture shape and processing stepover on the dry friction and wear performance of the samples were investigated using a ball-and-disk friction tribometer. The results showed that all the USRP texturing samples had lower friction coefficients and wear rates than those of the substrate sample under dry friction conditions. The best tribological performance was achieved at the stepover of 150 μm for linear textures and 250 μm for cross textures. For two shapes of textures with the same stepover, the linear texture had better wear resistance and the cross texture had better friction reduction. The texture shape and processing stepover influenced the texture height and the strengthening effect, which in turn affected the tribological properties of the samples. The improvement in friction and wear performance by ultrasonic rolling texturing was attributed to the synergistic effect of the strengthened substrate, reduced actual contact area, and entrapment of wear debris.

Automatic strength assessment of the virtually modelled concrete interfaces based on shadow-light images

The interface between concrete layers cast at different ages is present both in new construction, e.g., precast beams with cast in place decks, and in rehabilitation, e.g., jacketing of existing beams and columns. The interface strength ensures the element’s monolithic behaviour. This strength is mainly determined by the interface surface roughness. Unlike other material parameters, the interface strength is accessed with deterministic parameters (cohesion and friction) making design dependent on their correct assessment. Within this framework, the research study herein described aims to find non-deterministic parameters of the interface strength and an automatic method for their evaluation. The proposed parameters are derived from best-fit geostatistical models for roughness. These parameters are neither deterministic nor used for roughness and strength evaluation but they describe natural phenomena well. The automatisation is obtained via the deep learning process of the interface texture and strength. Since this process requires huge and not available data, real sources of data (i.e. surfaces) are substituted with the virtual Gaussian models generated with the geostatistical parameters obtained from the real surfaces. A similar process can be applied to the strength data if available in sufficient numbers. For short, the paper presents the application of the geostatistical parameters to the evaluation of both surface texture and strength of concrete to concrete interface, which have not been used before. It is shown that these parameters can be used to ‘store’ surface data in a compact form and subsequently texture or strength virtual reproduction is possible making deep learning and automatisation possible to perform.

Enhanced Anticorrosion and Antifouling Properties of Lubricant‐Infused Pyramidal Polydimethylsiloxane Coating

AbstractAlthough slippery liquid‐infused porous surfaces (SLIPSs) have been extensively studied for anticorrosion and antifouling applications, their durability and stability restrict their practicality. Herein, a technique is presented for fabricating SLIPS with dual‐protection. First, a polydimethylsiloxane (PDMS) coating with a pyramidal morphology is fabricated through mold‐based lithographic techniques. The mold is prepared by applying a texturing process to a monocrystalline silicon wafer of the type used to produce solar cells. Once infused with lubricant, the SLIPS is prepared and has a water‐contact angle of 112°, on an inclined surface, water droplets slide easily off its surface. Due to the excellent chemical stability and low superficiality of the lubricant layer, the SLIPS offers excellent antifouling and anticorrosion properties. In a static marine environment, the SLIPS has an extremely low coverage fraction of algae. After being immersed in a 3.5% NaCl solution for 400 days, |Z|0.01 Hz ≈ 1011 Ω, and the phase angle at high frequency is approximately −90°. SLIPSs based on the PDMS coating provide dual protection (anticorrosion and antifouling), showing that this design approach produces SLIPSs with excellent potential for applications in marine environments.

Novel laser texturing of W-doped VO2 thin film for the improvement of luminous transmittance in smart windows application

Vanadium dioxide is a promising material for application in smart windows, which undergoes a metal-to-insulator transition, MIT, at 68 °C accompanied by a structural phase transformation, SPT, from VO2(M1) to VO2(R). In this study, two VO2 thin films, one W6+-doped and another one undoped, have been prepared. Both were synthesized via polymer-assisted sol–gel route. The effect of doping on thermochromic parameters was evaluated, giving rise to a reduction of the phase transition temperature by 21 °C with an IR modulation capability of 20 % in the doped sample. Additionally, doping effect on the thermochromic parameters and nanomechanical properties has been analyzed by Spectrophotometry and Atomic Force Microscopy. With the aim of recovering the luminous transmittance that decreased because of doping, the sample has been subjected to an innovative laser texturing process. This laser treatment is able to increase the luminous transmittance by almost 40 % without negatively affecting the other thermochromic parameters. Results show that the combination of both strategies, doping and laser texturing, leads to the production of VO2 thin films with low critical temperature, high solar and IR modulation capacity and enhanced luminous transmittance, with values close to those required for their real application in smart windows.

Controllable fabrication of microstructures on the metallic surface using oblique rotary ultrasonic milling

Rotary ultrasonic milling emerges as a new and efficient fabrication method for surface microstructures. However, a phenomenon of secondary back-cutting interference exists in conventional rotary ultrasonic milling. It destroys the fabricated microstructure and leads to poor controllability of the surface geometries. In this study, oblique rotary ultrasonic milling (ORUM) is proposed to improve the process controllability by eliminating secondary back-cut interference. In the ORUM, the tool rotation axis is slightly inclined with an oblique angle of around 0.15°. In this way, surface texturing can be established by face milling without secondary back-cutting interference. A kinematic model was developed to predict the surface geometries of fabricated microstructures. Finite element analysis was performed to explore the material removal behavior for different vibration trajectories. Moreover, surface texturing tests were conducted on aluminum and titanium alloy to verify the efficacy of the proposed texturing process. The experimental results showed that the ORUM could texture microstructures on the metallic surface with much better geometric regularity than conventional ultrasonic milling. The model-predicted surface morphology of microstructure agrees well with the experimental results, verifying the high process controllability of ORUM. The effects of process parameters, including the depth-of-cut, spindle speed, and feedrate were presented to further demonstrate the process flexibility of ORUM in terms of the geometry adjustment of microstructures. Finally, fish-scale microstructures were fabricated on freeform surfaces like aircraft wings and implant hip joints, which implies the potential of ORUM for industrial applications.