Fabricating Microstructures on Freeform Surfaces via Flexible Hydrogel Micromolds.

Metal Additive Manufacturing (MAM) has significantly simplified the design and production of complex components. However, achieving high-quality surface finishes remains a major challenge, particularly in Directed Energy Deposition (DED) technologies such as Laser Wire, Wire Arc, and Laser Powder Additive Manufacturing. To ensure parts are suitable for practical applications, post-processing is often required to enhance surface quality. This study presents a comprehensive evaluation of the surface topography and characteristics of stainless steel 316L parts fabricated using metal laser additive manufacturing techniques, including Wire Laser Directed Energy Deposition (WLDED) and Powder Laser Directed Energy Deposition (PLDED). Surface properties such as average roughness (Ra) and root mean square roughness (Rq) were measured using a surface roughness tester. The analyzed skewness (Rsk) and kurtosis (Rku) of the surfaces provided insights into the shape of roughness. To achieve improved surface quality, the ideal setting of process parameters, including laser power, scan speed, and feed rate, not just varies with the process used but also depends on which roughness parameter is prioritized. For example, PLDED at 600 W, 5-7.5 mm/s scan speed, and 4 g/min feed rate gives the best surface smoothness (Ra and Rq), but achieves minimum Rz at 500-600 W, 5 mm/s, and 4 g/min. Whereas, WLDED performed best in terms of Ra, Rq, and Rz at 1025 W, 8 mm/s, and 10 mm/s. This work highlights how surface topography varies across different AM processes in their optimized states, offering valuable guidance for selecting the most suitable AM technique based on surface finish requirements and application priorities. By addressing the critical challenge of roughness, the study bridges the gap between current manufacturing limitations and the growing demand for high-precision, application-ready parts. This research seeks to guide the advancement of enhanced AM processes, promoting innovation in industries such as aerospace, medical implants, and automotive engineering, where superior surface quality is essential. The findings help manufacturers refine their methods, reducing the need for extensive postprocessing while maintaining functional integrity.

To ensure the good performance of hyper-numerical-aperture (NA) freeform surfaces lithography objective, not only the aberration should be decreased as much as possible in theory design stage, but also all the tolerances should be allocated reasonably and controlled rigorously in the manufacturing process. Therefore, reasonable tolerance analysis for projection objective is needed to maximally make up for the image quality deterioration caused by manufacture and assembly errors. According to the variation sensitivity between Zernike aberration and the single tolerance, effective compensators for individual aberrations can be chosen during tolerance analysis. As an example the method is applied to the tolerance analysis for an NA1.2 catadioptric projection objective with freeform surfaces designed by us. The results show that, after tolerance analysis using the compensators selected by this method, the root mean square (RMS) wavefront error of the projection objective is less than 0.015λ (λ=193 nm) at 90% probability, which meets the image quality requirement of lithographic projection objective for 10 nm technology node.

The efficiency and safety of root canal preparation are significantly influenced by the surface topographies of rotary files. Atomic force microscopy (AFM) provides high-resolution imaging that can reveal detailed surface characteristics of these instruments. In this study, three types of rotary files (File A, File B, and File C) were used to prepare the root canals of extracted human molar teeth. A total of 30 molar teeth were divided into three groups (n = 10) and prepared using one of the three rotary files. After preparation, the rotary files were analyzed using AFM to measure surface roughness parameters including average roughness (Ra), root mean square roughness (Rq), and maximum peak height (Rp). Statistical analysis was performed using ANOVA and post hoc tests to compare the differences between the groups. The AFM analysis revealed significant differences in the surface topographies of the rotary files. File A exhibited a Ra of 150 nm, a root mean Rq of 180 nm, and a maximum peak height Rp of 300 nm. File B showed an average roughness (Ra) of 200 nm, a root mean Rq of 230 nm, and a maximum peak height (Rp) of 350 nm. File C had an average roughness (Ra) of 170 nm, a root mean Rq of 210 nm, and a maximum Rp of 320 nm. Statistical analysis indicated that File B had significantly higher roughness parameters compared to File A and File C (P < 0.05). The surface topographies of rotary files vary significantly, which may impact their performance in root canal preparation. File B, with the highest roughness parameters, may pose a greater risk of canal wall damage and debris retention. These findings underscore the importance of selecting appropriate rotary files to optimize endodontic treatment outcomes.

Ultra-precision freeform surfaces are complex surfaces that possess non-rotational symmetry and are widely used in advanced optics applications. Due to the geometrical complexity of optical freeform surfaces, there is, as yet, a lack of generalized surface characterization methods which measure various types of ultra-precision freeform surfaces with sub-micrometer form accuracy and surface finish in the nanometer range. To make good this deficiency, a generalized approach for the measurement and characterization of ultra-precision freeform surfaces, named the intrinsic surface feature-based method (ISFM), is presented in this paper. The ISFM makes use of intrinsic surface properties (e.g. curvatures, normal vectors, torsion and intrinsic frames) to conduct data matching or uses some algorithms to search for correspondences such as correlation functions. The method is experimentally verified through a series of measurement experiments. The results show that the proposed ISFM is capable of addressing the deficiencies and limitations of traditional freeform surface characterization methods which are susceptible to outliers and to uncertainty due to the geometry of the freeform surfaces. ISFM is a generalized methodology which is not dependent on the type of freeform surface being characterized.

Irregularity of an optical surface is commonly characterized by peak-to-valley or root mean square error after subtraction of low order aberrations. It is sufficient if the surface is fabricated with the help of conventional techniques. Modern manufacturing methods employ undersized polishing tools generating irregularities on sub-aperture scales or mid-spatial frequencies. This is particularly important for the fabrication of aspheric or free-form surfaces. The smoothness of local polishing depends on how uniformly the influence of a tool is distributed and how well the dwell time is controlled over a part. Diamond turning is known for the variety of shapes, however, a single point tool tends to form surface features on the scale determined by the uniformity of feed rate. A deterministic way to quantify and specify mid-spatial irregularity is important for all areas of optical production. Interferometric map of an optical surface is usually obtained from original data by subtraction of the fit of 9 Zernike fringe polynomials corresponding to piston, tilt, focus and third order astigmatism, coma and spherical aberrations. This paper describes how to characterize the spectral content of residual surface height error, which depends on multiple factors during the fabrication. To quantify small scale irregularities, the residual error is regarded as a statistical process. The method of structure function is applied to the surface errors at different spatial scales yielding RMS height difference vs. physically measurable separation on an optical surface.

Multi-channel common-aperture optical systems, which excel at simultaneous multi-spectral information acquisition, are widely used for image fusion. However, complex systems for long-distance multi-band detection suffer from difficulties in assembly and adjustment and light vignetting. To resolve this, the paper proposes a modular design method that splits the optical path into independent modules: the common-aperture optical path adopts an off-axis reflective beam-shrinking structure to extend the focal length and ensure 100% light input, compared with coaxial multi-channel common-aperture systems. The relay optical path of each spectral channel uses a continuous zoom design for smooth detection–recognition switching. Based on the method, a three-channel common-aperture system is developed integrating visible light (VIS), short-wave infrared (SWIR), and mid-wave infrared (MWIR). The modulation transfer function (MTF) and wavefront distribution of the common-aperture optical path approach the diffraction limit. After integration with the relay optical paths, the system, without global optimization, can achieve the following performance: the root mean square (RMS) across the full field of view (FOV) at different focal lengths for each channel is smaller than the detector pixel size (3.45 μm for VIS, 15 μm for SWIR/MWIR); the MTF exceeds 0.2 at the cutoff frequency. Subsequently, the results of the tolerance analysis verify the feasibility of the design for each module and the advantage of the modular layout in the assembly and adjustment of the system. Finally, the paper discusses the influence of parallel plates on the wavefront distortion of the system and proposes optimization thinking using freeform surfaces. The design results of the study validate the feasibility of the modular layout in simplifying the design and assembly of multi-channel common-aperture optical systems.

Polyjet printing is an additive manufacturing technique for making structures from different photopolymer-based material systems. The technique involves a layer-by-layer deposition process for printing parts. Recent advancements in Polyjet technology include the ability to pause and resume print at specific slices, integrate electronics and mechanical parts in the model, use air as a medium for printing to create voids, and a feature to fabricate parts without substrate. When the print without substrate feature is used, the model material droplets are directly dropped onto the build tray without using the support material. In the print without substrate feature, the model material droplets interact with the hard metallic built tray, unlike the current feature: print with a substrate, where the model material droplets interact with the soft support material. The interaction mechanism governs the structure-property relationship, influencing the quality of the fabricated parts. The quality of a printed product depends on various parameters, including dimensional accuracy, surface finish, and mechanical characteristics of parts. Surface finish is one of the quality characteristics which depends on the process-induced effects. The current study investigates the influence of process-induced effects on the surface roughness characteristics of Vero material system in a Polyjet AM Setup. It evaluates the optimum combination of process parameters for better surface roughness characteristics by applying the Grey Taguchi method. The process parameters considered in the study include high-mix and high-quality mode of printing, build type, and print with-without substrate features available in the current Polyjet AM setup. Taguchi’s L4 (23) orthogonal array was used to develop the set of process parameters with their levels. Taguchi’s method is simple to conduct experiments with minimum repetitions. This method allows for optimizing the process parameters and helps establish a correlation among the variables. KLA Zeta 20 Optical Profiler was used to measure the surface roughness parameters Ra, Rq, and Rt at five different positions on the base of the printed samples along the direction of the print. Here Ra is the arithmetic average of the roughness values, Rq is the root mean square average of the roughness value, and Rt is the distance between the highest peak and lowest valley. Five one-inch blocks were printed for each set of combinations. Eight combinations of process parameters were considered, and 40 samples were printed. The experiments showed that the parts printed with substrate exhibited higher roughness values, whereas parts fabricated without substrate exhibited lower roughness values. The Grey Relational Grade (GRG) was evaluated for each experiment; the GRG shows the input parameters’ effect on the surface roughness characteristics. The GRG gives the optimal combination of input parameters for better surface roughness characteristics. For the current investigation, the best combination of input parameters for better surface quality is for the parts fabricated using the high-quality printing mode with matte build style and without substrate feature.

To investigate conditions of silver electroless deposition on silicon (100), optical microscope, atomic force microscope (AFM) and attenuated total reflection infrared spectroscopy (ATR-FTIR) spectroscopy were used. Twenty second dipping in 0.8mM AgNO3/4.9% solution coats a silicon (100) wafer with a thin film of silver nanoparticles very well. According to AFM results, the diameter of silver particles is from 50 to 100nm. After deposition, arithmetic average of absolute values roughness (Ra) increased from ~0.7nm to ~1.2nm and the root mean square roughness (Rq) is from ~0.8nm to ~1.5nm. SCN- ions were applied to detect the existence of silver on silicon surface by ATR-FTIR spectroscopy and IR spectra demonstrate SCN- is a good adsorbent for silver metal. Patina is the general name of copper basic salts which forms green-blue film on the surface of ancient bronze architectures. Patina formation has been found on the surface of platinum or ruthenium after several scans of cyclic voltammetry in 2mM CuSO4/0.1M K2SO4, pH5 solution. Evidence implies that oxygen reduction reaction (ORR) triggers the patina formation. ORR is an important step of fuel cell process and only few sorts of noble metals like platinum can be worked as the catalyst of ORR. Mechanisms of patination involving ORR were investigated by cyclic voltammetry, optical microscope, AFM, rotating disk electrode and other experimental methods: the occurrence of ORR cause the increase of local pH on electrode, and Cu2+ ions prefer to form Cu2O by reduction. Patina forms while Cu2O is oxidizing back to Cu2+.

The objective of this study was to design and evaluate an orodispersible film (ODF) composed of aripiprazole (ARP), prepared using a conventional solvent casting technique, and to fuse a three-dimensional (3D) printing technique with a hot-melt extrusion (HME) filament. Klucel® LF (hydroxypropyl cellulose, HPC) and PE-05JPS® (polyvinyl alcohol, PVA) were used as backbone polymers for 3D printing and solvent casting. HPC-, PVA-, and ARP-loaded filaments were applied for 3D printing using HME. The physicochemical and mechanical properties of the 3D printing filaments and films were optimized based on the composition of the polymers and the processing parameters. The crystalline states of drug and drug-loaded formulations were investigated using differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). The dissolution and disintegration of the 3D-printed films were faster than those of solvent-cast films. HPC-3D printed film was fully disintegrated within 45 ± 3.5 s. The dissolution rate of HPC films reached 80% within 30 min at pH 1.2 and pH 4.0 USP buffer. There was a difference in the dissolution rate of about 5 to 10% compared to PVA films at the same sampling time. The root mean square of the roughness (Rq) values of each sample were evaluated using atomic force microscopy. The higher the Rq value, the rougher the surface, and the larger the surface area, the more salivary fluid penetrated the film, resulting in faster drug release and disintegration. Specifically, The HPC 3D-printed film showed the highest Rq value (102.868 nm) and average surface roughness (85.007 nm). The puncture strength of 3D-printed films had desirable strength with HPC (0.65 ± 0.27 N/mm2) and PVA (0.93 ± 0.15 N/mm2) to prevent deformation compared to those of marketed film products (over 0.34 N/mm2). In conclusion, combining polymer selection and 3D printing technology could innovatively design ODFs composed of ARP to solve the unmet medical needs of psychiatric patients.

Atomic force microscopy technique for the surface characterization of sol–gel derived multi-component silica nanocomposites

This study addressed the critical challenge of systematic alignment errors in freeform surface measurement, which arose from spatial deviations between design and measurement coordinate systems. An enhanced Coherent Point Drift (CPD) registration method incorporating 3D-Harris feature point extraction was proposed. The methodology employed the 3D-Harris operator to extract local curvature feature points, significantly reducing data volume while preserving essential geometric characteristics. An initial coarse registration was achieved through coordinate transformation of the feature point set, followed by precision fine registration using the CPD algorithm enhanced with local structural constraints. Comprehensive experiments using the standard Bunny model and freeform surface measurement data demonstrated the superior performance of the proposed method. Compared to conventional CPD algorithms, the method achieved reductions of 34% in peak-to-valley (PV) error and 31% in root-mean-square (RMS) error on the Bunny model, along with a 77% reduction in computation time. For freeform surfaces, the method attained exceptional precision with PV = 11 nm and RMS = 7 nm registration errors, while maintaining high efficiency with a processing time of approximately 1.4 seconds. These results confirmed the effectiveness of the proposed approach in achieving high-precision and high-efficiency point cloud registration for freeform surfaces.

Force and vibration generated in apical direction by three endodontic files of different kinematics during simulated canal preparation: An in vitro analytical study.

In this study, we investigated the surface morphology of the liquid-crystalline polymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2) film by high performance atomic force microscopy and the surface roughness parameters of the F8T2 film such as; roughness average (sa), root mean square roughness (sq), surface skewness (ssk) and surface kurtosis (sku) value were obtained. Also, we reported the morphology of the cross-section (wall) and height histogtams of the F8T2 film by AFM. The positive skewness and high kurtosis of the F8T2 film are desirable to achieve low friction applications. The ratios of the sq to the sa for the F8T2 film were found to be 1.271 and 1.292. Then, we investigated in detail the optical properties of the solutions of the F8T2 polymer for different molarities and solvents. The absorbance, molar extinction coefficient (e) and mass extinction coefficient (α) values of the F8T2 polymer decrease with decreasing molarity. The average transmittance, absorption band edge, direct (Egd) and indirect (Egid) energy-gap values of refraction of the F8T2 polymer increase with decreasing molarity. The maximum absorption wavelength (λmax) of the solutions of the F8T2 for 1.200 and 0.800 µM was found to be 455 nm, while the λmax of the F8T2 polymer for DCM, THF and Chloroform solvents were found to be 447, 453 and 455 nm, respectively. The yellow light of the F8T2 polymer is emitted 586 nm. The maximum mass extinction coefficient (αmax) values at maximum molar extinction coefficient (emax) (2.246x106 and 1.736x106 Lmol-1cm-1, respectively) of the solutions of the F8T2 polymer for 1.200 and 0.800 µM were found to be 59.105 and 45.684 Lg-1cm-1, respectively, while the αmax values at emax(2.461x106, 2.371x106 and 2.246x106 Lmol-1cm-1, respectively) of the F8T2 polymer for DCM, THF and Chloroform solvents were found to be 64.763, 62.395 and 59.105 Lg-1cm-1, respectively. The Egd values (2.413 and 2.387 eV, respectively) of the F8T2 polymer for 0.800 µM and Chloroform solvent are the highest values, while the Egd values (2.220 and 2.279 eV) of the F8T2 polymer for 19.737 µM and THF solvent are the lowest values. The Egid values (2.345 and 2.305 eV, respectively) of the F8T2 polymer for 0.800 µM and Chloroform solvent are the highest values, while the Egid values (2.113 and 2.053 eV) of the F8T2 polymer for 19.737 µM and THF solvent are the lowest values. The obtained Egid values of the F8T2 polymer are more lower than that of the obtained Egd values of the F8T2 polymer. Thus, the optical band-gap of the solution of the F8T2 polymer was decreased with increasing molarity and using THF solvent among DCM, THF and Chloroform solvents

Three-Dimensional Quantitative Comparative Analysis of Trapezial-Metacarpal Joint Surface Curvatures in Human Populations

The aim of the present research is to calculate the Relative Accuracy (R.A) and Root Mean Square Error (RMSE) for the location of Technical Institute, Mosul in Nineveh Governorate, Iraq. at the northern part of Mosul city by using surveying Instruments (GPS 1230 , Total Station 06 & Level NAK2), to calculate the coordinates and elevations of (16) Ground Control Points which covered the study area. The field data, remote sensing techniques and GIS software (Arc Map GIS10.3) are used to check the digital map of study area that helped the administrator to take the correct decision, determining positions of the future expansionist for buildings, roads, measuring lengths, areas and there coordinates, directions as well as the total costs estimation needed for any development from the final map. The gradient percentage between the highest and lowest points is calculated to be (9.954%). Relative accuracy for the based measured points (R.A) = 1:60000), and Root Mean Square error in Easting coordinates (RMSE) = ± 0.102m, in Northing coordinates (RMSN) = ± 0.096m, the Root Mean Square for the resultant (RMSR) = ± 0.099m, and Root Mean Square for Elevations ( RMSRL)= ± 0.005m. We Matched and correlated (10) measured points from study area with their graphic data positions on the aerial photo, determining the offsets for position and elevations as follows: (RMSE = ± 0.076m), (RMSN = ± 0.125m), (RMSR = ± 0.088m), and (Root Mean Square for Elevations = RMSRL= ± 0.045m). This research enable us after checking the results to produce new maps from Aerial photograph or Digital Image to use it for land uses and future extensions in whole study area.