3D Microscopy Research Articles

The Impact of 3D Microscopy Strategies on Computational Analysis for Battery Research.

The Impact of 3D Microscopy Strategies on Computational Analysis for Battery Research.

Could facing techniques be compatible with optimal bone preservation surface?

Bone usually requires conservation treatment during excavation. Some of the most common interventions are facing techniques to reinforce the specimens during their extraction in the field. This consists of the attachment of a fine tissue with a reversible adhesive, usually an acrylic resin, directly over the surface of the specimen. This interacts directly with the surface, which might link to the loss of bone surface information. This experiment focuses on the possible modifications that facing techniques could cause on bone surfaces with cut marks. Experimental bones with cut marks were artificially aged to reproduce the decayed process of archaeological bones. Different groups of bone samples were faced and exposed in two contexts for one year: indoors and outdoors. Bone surface and cut marks were documented before and after the facing and storing phases with 3D Digital Microscopy. In the indoor bones, cut marks show abundant traces of resin. Conversely, bones preserved in an outdoor environment displayed a high modification of their colour and an extremely poor state of preservation. Some cut marks disappeared completely or partially. Visual comparison allowed us to evaluate possible loss of archaeological information produced by the treatments. Facing techniques should be carefully monitored to guarantee its short-term contact with the bone surface and avoid these modifications.

3D Morphology of Different Crystal Forms in β-Nucleated and Fiber-Sheared Polypropylene: α-Teardrops, α-Teeth, and β-Fans.

Polymorphism of semicrystalline polymers has significant influence on their physical properties, with each form having its advantages and disadvantages. However, real-life polymer processing often results in different coexisting crystal polymorphs, and it remains a challenge to determine their shape, spatial distribution, and volume fraction. Here, i-polypropylene (i-PP) sheets containing both α- and β-forms were prepared either by adding β-nucleating agent or by fiber pulling-induced crystallization. By adding a compatible dye that is partially rejected from the growing crystalline aggregates (spherulites and cylindrites), we visualize the shape of these objects in 3D using two-photon fluorescence confocal microscopy. To distinguish between crystal forms, we take advantage of the difference in dye-retaining ability of the α- and β-aggregates. Even in 2D, fluorescence microscopy (FM) distinguishes the two crystal forms better than polarized microscopy. In 3D imaging, the volume fraction and spatial distribution of α- and β-forms in different morphological types could be determined quantitatively. Morphologies described as α-teeth, β-fans, and α-teardrops were visualized for the first time in 3D. Furthermore, internal and surface microcracks were seen to be associated predominantly with the β-form and around the fiber. Spatial distribution of α- and β-forms was also determined by scanning with a synchrotron X-ray beam. Good agreement was obtained with 3D microscopy, but XRD could not match the detail obtainable by the tomography. The work demonstrates the ability of the 3D imaging method to distinguish different crystal forms and their specific morphologies.

Investigate on the dry friction tribological behaviors and mechanism of carbon quantum dot/polyimide composites coating

The comprehensive utilization of biomass resources is to be prepared into functional nanomaterial. This paper prepared carbon quantum dots (CQDs) using citric acid. A new CQDs/polyimide composites (CQDs/PI) coating fabricated on the surface of steel disks, has been widely used in bearing sleeve material or coatings in marine equipment parts and aerospace industries. Tribological properties of coating materials were investigated at different loads and reciprocating speeds of 10 mm/s under dry sliding conditions using a UMT-2 tribometer and compared to those of commercial MoS2 particles in PI composites. Scanning electron microscopy accompanied by energy spectroscopy (SEM/EDS) and 3D laser scanning microscopy were used to characterize the morphologies of the abrasion marks to clarify the tribological mechanisms. Results show that different levels of CQDs can improve composite coatings' anti-wear and friction reduction properties. The tribological mechanisms of CQDs were attributed to the enhancement of the hardness of the polyimide coatings by the CQDs and the formation of a transfer film on the surface of the ceramic balls during the friction process reducing the direct contact at the friction sub-interface.1

Membrane polarization at the excitation threshold induced by external electric fields in cardiomyocytes of rats at different developmental stages.

External electric fields (E), used for cardiac pacing and defibrillation/cardioversion, induce a spatially variable change in cardiomyocyte transmembrane potential (ΔVm) that depends on cell geometry and E orientation. This study investigates E-induced ΔVm in cardiomyocytes from rats at different ages, which show marked size/geometry variation. Using a tridimensional numerical electromagnetic model recently proposed (NM3D), it was possible: (a) to evaluate the suitability of the simpler, prolate spheroid analytical model (PSAM) to calculate amplitude and location of ΔVm maximum (ΔVmax) for E = 1V.cm-1; and (b) to estimate the ΔVmax required for excitation (ΔVT) from experimentally determined threshold E values (ET). Ventricular myocytes were isolated from neonatal, weaning, adult, and aging Wistar rats. NM3D was constructed as the extruded 2D microscopy cell image, while measured minor and major cell dimensions were used for PSAM. Acceptable ΔVm estimates can be obtained with PSAM from paralelepidal cells for small θ. ET, but not ΔVT, was higher for neonate cells. ΔVT was significantly greater in the cell from older animals, which indicate lower responsiveness to E associated with aging, rather than with altered cell geometry/dimensions. ΔVT might be used as a non-invasive indicator of cell excitability as it is little affected by cell geometry/size.

Arc Erosion Properties of WCu Material Reinforced with Ti3SiC2under Different Applied Voltages

Introducing reinforcements is a crucial way to modify WCu electric contacts. Herein, the arc erosion performances of WCu/Ti3SiC2under various direct current voltages are investigated. The eroded microstructures are observed by a 3D laser scanning confocal microscopy and a thermal field emission scanning electron microscope. Compositions of the eroded surfaces are analyzed by a Raman spectroscopy. With the elevated voltages, values of breakdown current, arc duration, arc energy, and arc discharge distance increase, while the breakdown strength decreases. Meanwhile, the eroded regions gradually change from circular shape to irregularly curved corrugations under the elevated voltages. Copper and Ti3SiC2can disperse arc during arc discharge, and the liquid and gas generated by the two phases can make differences in protecting WCu/Ti3SiC2.

Green Machining of NFRP Material

Nowadays, great emphasis is placed on environmental aspects of production processes with focus to lower carbon footprint. Natural fibre-reinforced plastics (NFRP) show potential for application in many fields of industry due their specific properties. Machining of NFRP-based materials is meeting several problems arising from non-homogenous structure as well as plastic-based matrix. Machining of NFRP using conventional technologies meets limitations due to the properties and geometry of the tools. Abrasive water jet (AWJ) machining can solve some of the problems machining NFRP materials. The presented article focused on surface topography evaluation of one kind of NFRP composite material after cutting by AWJ. Optical profilometry and 3D microscopy were applied for measurement of surface roughness parameters of surfaces created by AWJ with variable cutting parameters. Maximal height of profile Rz was measured in 20 lines perpendicular to the jet direction form upper to lower cut line. Structure of cut surface was observed and evaluated for different technologic parameters. The obtained results show promising presuppositions for application of AWJ technology for cutting of NFRP based materials.

Reconstruction of the in-depth profile of line gratings with critical dimension grazing incidence small angle x-ray scattering on laboratory equipment

We present a reconstruction of the in-depth profile of line gratings using critical-dimension grazing incidence small angle x-ray scattering with a compact Cu-Kα x-ray source mounted on a laboratory small angle x-ray scattering (SAXS). By taking advantage of the grazing-incidence configuration and with a rotation of the gratings under the x-ray beam, several orders of the Bragg rods were probed and led to the extraction of the in-depth profile of the lines. The extracted in-depth profile is compared with 3D atomic force microscopy results. The methodology developed mimics the one of critical dimension SAXS measurements, in transmission, to enable future comparison between the two approaches as well as building complementary modeling. These results open new perspectives for in-line x-ray metrology since the Cu-Kα x-ray source is widely spread and used by the x-ray community.

P-197 Nuclear transfer with almost nonexistent mitochondrial carryover -a mouse model-

Abstract Study question Can the transfer of aggregated chromosomes (AC) as compared to spindle-chromosome transfer (SCT) reduce mitochondrial DNA (mtDNA) carryover and improve development rates? Summary answer The rate of mtDNA carryover after AC transfer was only 0.1%, which was much less than that of 2.0% after SCT. What is known already Nuclear transfer techniques such as SCT and pronuclear transfer have been applied to prevent mitochondrial diseases and to treat early embryonic arrest, however, the problem of mtDNA carryover has not yet been resolved. We previously reported on an AC transfer (ACT) method in humans which could overcome the above problem, however, consequent embryonic development rates have not been investigated in Japan due to legal restrictions and no animal study has been conducted, as the formation of ACs has not been found in any other species. Study design, size, duration Following our success in the creation of ACs in mouse oocytes using IBMX (3-Isobutyl 1-methylxanthine), a phosphodiesterase inhibitor, a mouse model of ACT was established. This was followed by a comparison of the rates of embryo development and mtDNA carryover in both ACT and SCT in over 100 oocytes. The distribution of mitochondria around SC and AC were also examined by confocal laser microscope (FV3000, Olympus, Japan). Participants/materials, setting, methods GV stage oocytes were collected from 8-12 week B6D2F1 mice. After GVBD, oocytes were incubated in KSOM medium, containing 3 mM IBMX, for 10-14 hours until AC is formed. ACs and SCs were injected into enucleated MII stage donor oocytes and then fertilized at the MII stage. Embryos were cultured for 5 days to compare the rates of embryo development. Enucleated ACs and SCs were subjected to real-time PCR, to analyze the carryover of mtDNA. Main results and the role of chance The rates of fertilization, embryo cleavage and blastocyst formation in AC oocytes without AC transfer (control), in ACT and in SCT were 60.7%, 55.9%, 13.2% (control), 82.5%, 80.8% and 30.8% (ACT), and 81.0%, 74.5% and 31.4% (SCT) respectively. The ACT group showed a significant increase in fertilization (P = 0.007), embryo cleavage (p = 0.008) and blastocyst formation (p = 0.034) rates, as compared to those in the control group. There were no significant differences between ACT and SCT regarding the rates of fertilization, embryo cleavage and blastocyst formation. The relative, real-time PCR showed that mtDNA carryover in the ACT group was 0.1% ± 0.07%, which was significantly lower than that in the SCT group of 2.0% ± 0.6% (p = 0.027). 3D confocal laser microscopy revealed that mitochondria were not localized around either SCs or ACs, as they were around pronuclei. Limitations, reasons for caution Although we succeeded in establishing a mouse model of ACT, validation in human oocytes is required to confirm the benefit of this method. Further experiments are required to confirm if healthy offspring can be obtained after ACT. Wider implications of the findings ACT could reduce the amount of mtDNA carryover and overcome heteroplasmy. As ACT improved the low embryo development rate caused by IBMX and had similar embryo development rates to SCT, the findings of this study may give rise to ACT being employed as a novel method for human nuclear transfer. Trial registration number not applicatable

Tribo-Mechanical Investigation of Glass Fiber Reinforced Polymer Composites under Dry Conditions.

Tribo-mechanical experiments were performed on Glass Fiber Reinforced Polymer (GRFP) composites against different engineering materials, and the tribological behavior of these materials under dry conditions was investigated. The novelty of this study consists of the investigation of the tribomechanical properties of a customized GFRP/epoxy composite, different from those identified in the literature. The investigated material in the work is composed of 270 g/m2 fiberglass twill fabric/epoxy matrix. It was manufactured by the vacuum bag method and autoclave curing procedure. The goal was to define the tribo-mechanical characteristics of a 68.5% weight fraction ratio (wf) of GFRP composites in relation to the different categories of plastic materials, alloyed steel, and technical ceramics. The properties of the material, including ultimate tensile strength, Young's modulus of elasticity, elastic strain, and impact strength of the GFPR, were determined through standard tests. The friction coefficients were obtained using a modified pin-on-disc tribometer using sliding speeds ranging from 0.1 to 0.36 m s-1, load 20 N, and different counter face balls from Polytetrafluoroethylene (PTFE), Polyamide (Torlon), 52,100 Chrome Alloy Steel, 440 Stainless Steel, and Ceramic Al2O3, with 12.7 mm in diameter, in dry conditions. These are commonly used as ball and roller bearings in industry and for a variety of automotive applications. To evaluate the wear mechanisms, the worm surfaces were examined and investigated by a Nano Focus-Optical 3D Microscopy, which uses cutting-edge μsurf technology to provide highly accurate 3D measurements of surfaces. The obtained results constitute an important database for the tribo-mechanical behavior of this engineering GFRP composite material.

Axial Resolution Enhancement of Optical Sectioning Structured Illumination Microscopy Based on Three-Beam Interference

As a branch of 3D microscopy, optical sectioning structured illumination microscopy (OS-SIM) has the advantages of fast imaging speed, weak photobleaching and phototoxicity, and flexible and compatible configuration. Although the method of using the one-dimensional periodic fringe pattern projected on the sample can remove the out-of-focus background from the in-focus signal, the axial resolution of the final reconstructed 3D image is not improved. Here, we propose a three-beam interference OS-SIM, namely TBOS, instead of the common-used dual-beam interference OS-SIM (DBOS). The three-beam interference scheme has been adopted in 3D super-resolution SIM (3D-SR-SIM), where the fringe phase shifting needs to be along each of the three orientations. In contrast, TBOS applies phase shifting only in one arbitrary direction. We built a TBOS SIM microscope and performed the 3D imaging experiments with 46 nm diameter fluorescent microspheres and a mouse kidney section. The axial resolution of the 3D image obtained with TBOS was enhanced by a factor of 1.36 compared to the DBOS method, consistent with the theoretical analysis and simulation. The OS-SIM with enhanced axial resolution for 3D imaging may find a wide range of applications in the biomedical field.

Functionally integrated waveguide illuminator for common-path digital holographic microscopy through random media.

We designed and fabricated a functionally integrated optical waveguide illuminator specially for common-path digital holographic microscopy through random media. The waveguide illuminator creates two point sources with desired phase shifts, which are located close to one another so that the common-path condition of the object and reference illumination is satisfied. Thereby, the proposed device permits phase-shift digital holographic microscopy free from bulky optical elements such as a beam splitter, an objective lens, and a piezoelectric transducer for phase shifting. Using the proposed device, microscopic 3D imaging through a highly heterogeneous double-composite random medium was experimentally demonstrated by means of common-path phase-shift digital holography.

A Detection Technique of Laser Pyrotechnics Sealing Quality Based on 3D Microscope with Super Depth of Field

Glass sealing is one of the key technologies in the assembly of laser pyrotechnics, the sealing quality will significantly affect the action performance of pyrotechnics. Therefore, it is necessary to detect the sealed laser pyrotechnics and eliminate unqualified products to improve the reliability of pyrotechnics. 3D microscope with super depth of field can realize stereoscopic observation, real-time measurement and high-definition imaging. It can be used to observe the microscopic morphological characteristics that cannot be directly seen by naked eye, and can also be used to carry out dimensional measurement. Thus, it has a desirable application prospect in many fields. In this paper, a quality detection technique of laser pyrotechnics sealing based on 3D microscope with super depth of field is explored, and the sealing effect of laser pyrotechnics is tested. This technique can be used to improve the glass sealing technics and enhance the reliability of laser pyrotechnics.

3D open-top light-sheet microscopy and 3D microdissection of neuoadjuvant-treated primary prostate cancer reveals latent subclonal mutations.

e17109 Background: Intratumoral molecular heterogeneity is a well described phenomenon in primary prostate cancer. Increased genomic heterogeneity is associated with more aggressive clinical behavior, including recurrence and metastasis. However, current methods to characterize heterogeneity suffer from tradeoffs between generating high quality morphologic information, correlating morphology with genomic alterations, and workflow considerations. We describe a technology to image prostate samples in 3D, perform 3D microdissection of regions of interest (ROIs), and preserve nucleic acids for DNA sequencing. Methods: Samples (N = 18) were obtained from patients (N = 12) enrolled in an open-label, single-site, Phase II neoadjuvant trial in men with NCCN high to very-high risk PC. Patients received 12 weeks of apalutamide, abiraterone acetate plus prednisone, degarelix, and indomethacin followed by radical prostatectomy (RP). Fresh frozen prostate samples (~2x2x0.4cm) were obtained from RP specimens. Frozen samples were fixed in an ethanol-based fixative, stained with nuclear (TOPRO-3) and general protein (eosin) fluorescent dyes, cleared with ethyl cinnamate, and imaged using 3D open-top light-sheet (OTLS) fluorescence microscopy. Image-guided 3D microdissection was performed on ROIs with distinct morphologies. Microdissected ROIs measured 0.5x0.5x2mm. Microdissected samples were sent for DNA extraction and sequencing using the comprehensive clinically-validated UW-OncoPlex NGS assay. Results: The tissue from neoadjuvant-treated patients contained sparse carcinoma, with cancer volumes ranging from 0.01-0.3 cm2 and cellularity ranging from 2%-30%. Molecular alterations were detected in a sample with only 0.07 cm2 volume of carcinoma with 5% cellularity. The read depth of 3D microdissected samples was 3.9 times greater than the read depth of FFPE samples from the same patients. At least two morphologically distinct ROIs were 3D microdissected from 11 of 12 patients. Four of the 18 samples had molecular alterations that differed between ROIs, i.e. intra-sample molecular heterogeneity. For example, one sample with three microdissected ROIs had a PTEN alteration exclusive to a single ROI. Conclusions: The findings show the potential for 3D microdissection of morphologically distinct subclones in samples from neoadjuvant-treated patient, to enable sequencing of specific cellular populations. The sparsity of carcinoma necessitated a spatially targeted approach for extracting material for sequencing. The increased yield from avoiding FFPE processing and carcinoma enrichment from targeted 3D microdissection of carcinoma ROIs enabled the detection of spatially distinct molecular subclones. Future work will include the analysis of additional samples and implementation of AI-guided ROI detection to streamline workflows.

Anti-erosion effect of an experimental varnish on eroded dentin.

This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

Development of a kidney cancer ex vivo tumor model and image-based artificial intelligence tool for precision immunotherapy and combination therapy testing.

e16525 Background: Immuno-oncology (IO) initiated a major shift in the cancer treatment paradigm, as therapies no longer target cancer cells directly but rather restore and exploit a patient’s own antitumor immunity. However at present, there are no conclusive diagnostic tools capable of predicting combination immunotherapy response with high accuracy in renal cancer. We’ve developed an ex vivo IO model and multivariate analysis to predict clinical drug efficacy by combining patient tumor samples, functional assays, artificial intelligence and omics. This model recapitulates each patient’s tumor-immune microenvironment (TiME) and allows time-course bulk and single-cell resolution analyses of functional metrics in 3D. Methods: Human renal tumor resections and matched blood (N=20 REC approved) were processed for spatial transcriptomics and single cell isolation of tumor and PBMCs. Tumor-dissociated (tumor, stromal, immune, etc.) cells and PBMC subsets were characterized by flow cytometry (FCm). Target cells (tumor) and effector cells (PBMCs and subsets thereof, CD8+) were stained with different fluorescent dyes including viability probes (caspase 3/7, SYTOX) and encapsulated in hydrogels that recapitulate human TiME physiology. Cultures were treated with approved regimens including immune checkpoint (ipilimumab, pembrolizumab) and receptor-tyrosine kinase (TKI)(cabozantinib, lenvatinib) inhibitors. Cells were tracked over 7 days using 3D time-course confocal microscopy. Computer vision analysis detected and quantified behaviors such as immune infiltration, immune/tumor cell migration, T cell-mediated tumor killing and tumor viability in response to treatments. Results: Our preliminary data shows that treatment with pembrolizumab resulted in a 26% increase in the infiltration of CD8- PBMC fraction into the microtumor core and a 14% increase in infiltration of the CD8+ subset. Tumor cell death was 15% higher in pembro-treated samples compared to untreated and 30% higher compared to tumor cultures alone (no PBMCs). Migration speed of immune cells was found to be higher as cells invaded and slower through engagement/killing, peaking at day 1 (3 µm/min) and slowing to 2 and 1.5 µm/min for CD8+ and CD8- cells by day 3. FCm was used to characterize tumor cell subpopulations (cancer, endothelial, immune) and the expression of targets in each patient. Treatment with TKIs led to reduced phosphorylation of VEGFR, PDGFRβ and HGFR (N=3). Conclusions: Our platform allows time-course analysis of functional cell response metrics. The model tests treatment combinations across multiple modes of action and quantifies cell response including viability, death, migration, infiltration and immune-surveillance. Future work aims to further develop the platform to match/predict patient responses in breast (NCT05435352), kidney, and other tumors.

Photorealistic 3-Dimensional Models of the Anatomy and Neurosurgical Approaches to the V2, V3, and V4 Segments of the Vertebral Artery.

The vertebral artery (VA) has a tortuous course subdivided into 4 segments (V1-V4). For neurosurgeons, a thorough knowledge of the 3-dimensional (3D) anatomy at different segments is a prerequisite for safe surgery. New technologies allowing creation of photorealistic 3D models may enhance the anatomic understanding of this complex region. To create photorealistic 3D models illustrating the anatomy and surgical steps needed for safe neurosurgical exposure of the VA. We dissected 2 latex injected cadaver heads. Anatomic layered dissections were performed on the first specimen. On the second specimen, the two classical approaches to the VA (far lateral and anterolateral) were realized. Every step of dissection was scanned using photogrammetry technology that allowed processing of 3D data from 2-dimensional photographs by a simplified algorithm mainly based on a dedicated mobile phone application and open-source 3D modeling software. For selected microscopic 3D anatomy, we used an operating microscope to generate 3D models. Classic anatomic (n=17) and microsurgical (n=12) 3D photorealistic models based on cadaver dissections were created. The models allow observation of the spatial relations of each anatomic structure of interest and have an immersive view of the approaches to the V2-V4 segments of the VA. Once generated, these models may easily be shared on any digital device or web-based platforms for 3D visualization. Photorealistic 3D scanning technology is a promising tool to present complex anatomy in a more comprehensive way. These 3D models can be used for education, training, and potentially preoperative planning.

A high temporal-spatial resolution three-dimensional imaging method using arrayed-focus structured illumination with differential axial enhancement

High precision and fast three-dimensional (3D) microscopic imaging technology plays an extremely important role in MEMS, micro optics, microelectronics, biomedicine and other fields. In this paper, a confocal microscopic 3D imaging method based on differential array focusing structured light illumination (DAF-SIM) is proposed. Theoretical analysis and experimental results show that under the 100x/NA 0.95 objective lens, the lateral resolution of this method reaches 173 nm, exceeding the optical diffraction limit, the axial sensitivity is better than 10 nm, and the time resolution is about 3 Hz@2.3 M Pixel, achieving the goal of high horizontal and axial resolution and time resolution. The high spatial and temporal resolution of DAF-SIM 3D micro imaging method provides a highly applicable, efficient and high-precision online micro terrain detection scheme for intelligent manufacturing and other fields.

Surface quality investigation in surfactant-based EDM of Inconel 617 using deep cryogenically treated electrodes

Surface quality governs the physical, mechanical, tribological, physio-chemical, and biological properties of materials. Considering the excellent mechanical characteristics of Inconel 617 and the nature of its intended applications, electric discharge machining is generally engaged. However, there is still a need to uplift the surface quality of machined parts to improve their working life and performance. Therefore, this study revealed the potential of deep cryogenically treated (DCT) electrodes under dielectrics modified with span and tween in the said context using a full factorial experimental design. Experimental findings are deeply investigated by employing 3D surface profilometry, scanning electron, and optical microscopy. Cryogenically treated electrode(s) have demonstrated a better surface quality in comparison to the non-treated electrodes, such as DCT Cu has provided a 25.5% lower roughness value than non-treated Cu. Referring to the role of additives, there exists a reduction of 32.5% in roughness when DCT brass is used instead of typical brass using a mixture of span-20 (S-20) and kerosene as a dielectric. The surface finish given by the cryogenically treated brass is 18.99% better when compared to the average value given by all cryogenically treated electrodes considered in this study. It has also been revealed that tween-based dielectrics gave 83% better surface finish than span-based dielectrics with DCT electrodes.

Fabrication of superhydrophobic surfaces on a glass substrate via hot embossing

This study developed a new hot pressing process to prepare superhydrophobic surfaces with controllable shape and size on a glass substrate. Microstructures were fabricated on tungsten carbide mold via picosecond laser processing. Microgroove structures were reproduced on glass during the hot embossing process and SiO2 nanoparticles laid on the mold were also embedded into the glass surface under the action of heat and pressure to provide nanostructures. The contact angle of the superhydrophobic glass surface reached up to 161.8°, and the sliding angle was only 3°. The structures and chemical composition of superhydrophobic glass surface were identified by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), X-ray diffraction (XRD), and Fourier transformed infrared (FTIR) spectroscopy. The 3D laser scanning microscopy result showed the height (20 μm) of the microgroove structures, while white light interferometry revealed the surface roughness (Ra 2.725 μm). The superhydrophobic glass surface demonstrated satisfactory temperature resistance and chemical stability through temperature and acid and alkali solution immersion tests. The surface exhibited certain mechanical stability by friction and wear test. This work provides a new hot embossing method for solving the problem of structural consistency and mass production of superhydrophobic glass, and will have great application prospects in the engineering field.