Surface Grooves Research Articles

Heat Transfer Analysis of Cooling Structure of Deuterium-Tritium Fusion Neutron Generator Target

A deuterium-tritium fusion neutron generator can produce high-intensity monoenergetic neutrons, which is important for the research and development of nuclear technology, and the neutron target is one of the crucial components of a neutron generator. For the neutron target, the most important technical index is the temperature of the target. Excessive temperature could impact the efficiency of nuclear reactions on the target surface and lead to target damage. Consequently, the thermal-hydraulic performance of the neutron target is significant for the performance of the neutron generator. In this paper, a curved channel with surface grooves was designed for the neutron target of a high-intensity neutron generator under design. The influence and mechanism of the curved angle and groove angle on the thermal-hydraulic performance of the minichannel were studied with the computational fluid dynamics method. The results indicated that a 45-deg curved channel with 135-deg surface grooves could enhance the turbulence within the minichannel, effectively improving the heat transfer performance of the neutron target with less pressure loss. Thus, the neutron target could withstand a higher-energy deuterium beam bombardment, increase neutron yield, and ease the pressure requirements on the cooling water pumps and sealing components.

Experiment of droplet anisotropic wetting behavior on micro-grooved PDMS membranes.

Wetting behavior of droplets on a substrate with micro-grooves plays a key role in super-hydrophobicity. This paper aims to study the influence of groove width, droplet size, and surface tension on the anisotropic wetting behavior of droplets on micro-grooved PDMS membranes. Three types of PDMS membranes are made by mold replication. Profiles of droplets along the circumferential direction are observed by HD camera, and the 3D model of the droplet is reconstructed. Capillary forces at the three-phase contact line are obtained using the surface tension integration method. Additionally, liquid's wetting depth within the micro-grooves is calculated using an interfacial free energy equilibrium approach. The experiment shows that the micro-grooved PDMS membrane has anisotropic constrain to droplets due to wetting depth change in micro-grooves. Meta-equilibrium states at the three-phase contact line are influenced not only by substrate free energy, but also by wetting depth, interface pressure, and substrate structure.

State-of-the-Art Review of Microcapsule Self-Repairing Concrete: Principles, Applications, Test Methods, Prospects

Cement-based materials are widely used in construction worldwide, but they are vulnerable to environmental stressors and thermal fluctuations, leading to the formation of internal cracks that compromise structural integrity and durability. Traditional repair methods such as surface coatings, grouting, and groove filling are often costly and labor-intensive. In response, self-repairing technologies for cement-based materials have emerged as an innovative and promising solution, offering the potential to significantly extend the lifespan of structures and reduce maintenance costs. A particularly novel approach is the development of microcapsule-based self-repairing concrete. In this system, repair agents are encapsulated within microcapsules and combined with curing agents in the concrete matrix. When cracks form, the microcapsules rupture, releasing the repair agents to autonomously heal the damage. This self-repairing mechanism is characterized by its high efficiency, durability, environmental sustainability, and versatility, making it a promising alternative to traditional repair methods. Recent research has focused on the development of microcapsules with various core materials, such as TDI (toluene diisocyanate), IPDI (isophorone diisocyanate), or epoxy resin, as well as composite shell materials including paraffin wax, PE (polyethylene) wax, nano-SiO2, and nano-CaCO3. A novel advancement in this area involves the enhancement of microcapsules through the incorporation of magnetic nanomaterials into the shell, providing new possibilities for self-repairing systems that address cracks in cement-based materials.

Efficient and Stable Wide‐Bandgap Methylammonium‐Free Perovskite Solar Cells by Simultaneous Passivation and Cleaning with Diamine

Wide‐bandgap perovskite solar cells (WBG‐PSCs) are pivotal in achieving high‐performance tandem solar cells. However, their power conversion efficiency (PCE) is limited by the losses from the interfacial charge transfer barrier and nonradiative recombination. In this investigation, 1,4‐bis(aminomethyl)benzene (PDMA) is employed as a defect passivator for fabricating methylammonium (MA)‐free perovskite solar cells (PSCs), thus effectively mitigating nonradiative recombination losses of charge carriers. Meanwhile, PDMA molecules chemically rinse the perovskite film to create a grooved surface, leading to the increase of contact area between the perovskite and electron transport layer to further improve the interfacial charge transfer. As a result, the PSCs based on these surface‐passivated and chemically cleaned perovskite films present a champion PCE of 21.23% (Eg = 1.68 eV) compared to the control devices with a PCE of 18.23%, while maintaining over 80% efficiency after 800 h storage in ambient air. This study presents a highly effective approach for one‐step passivation and chemical cleaning of wide‐bandgap perovskite for efficient and stable solar cells, offering valuable insights for future research in this field.

Influence of a dynamic gas film on underwater drag reduction

The gas film at the liquid–solid interface, induced by hydrophobic microstructure, can achieve a high-efficiency underwater drag reduction. However, previous studies have rarely considered the impact of changes in gas structure morphology on drag performance, especially under turbulent conditions. We conducted numerical simulations to examine the dynamic process of gas on a hydrophobic spanwise grooved surface under turbulent conditions. Our findings indicate that the morphology of the gas phase structure at the liquid–solid interface undergoes continuous alterations due to fluid action, resulting in a dynamic state of drag performance. In addition, the gas morphology that completely covers the groove surface will reduce the turbulent kinetic energy on the groove surface, resulting in a better drag reduction effect. In the flow velocity range of 10–20 m/s, the drag reduction effect of the superhydrophobic grooved surface increases with the flow velocity. Finally, we conducted experiments to validate the effectiveness of this result. A mechanism for underwater drag reduction was proposed based on these simulation results. This study offers a novel perspective on the phenomenon of underwater gas drag reduction, which could significantly influence its practical applications, especially under real working conditions.

Experimentally optimized anchored-FRP method: A high-strength, cost-effective and ease-to-install technique for concrete rehabilitation

Conventional EB-and NSM-FRP techniques tend to prematurely fail in FRP delamination, suggesting inefficient utilization of the FRP materials. Various anchorage systems have been developed by integrating FRP anchors with FRP patches or groove bond to maximize the utilization of FRP materials. This study proposes a simpler but robust method that can make full use of FRP materials while minimizing the need for groove excavation, FRP patches, epoxy adhesive and surface preparations. The reinforcement was achieved by externally bonding FRP reinforcement to the concrete surface, with bent anchors being embedded into the strengthened elements. 51 experiments were conducted to demonstrate the potentials of the proposed method, which successfully prevented premature debonding failure, thereby offering robust rehabilitation solutions with a reduction of up to 42 % in epoxy usage compared to current methodologies. The results also suggested the impact of key parameters, such as cross-sectional area, embedment depth, and multi-reinforcement arrangement, on the effectiveness of the proposed FRP technique. Based on the experimental findings, discussions and recommendations were presented to facilitate the continued advancement of the proposed FRP methodology, aiming to fully develop FRP strength and minimize the need for FRP materials and epoxy adhesive in comparison to the current anchored FRP methods.

Nanofluid effect on dual-flow parabolic trough collector performance accompanies with passive technique using experimental data

Purpose Using passive techniques like twisted tapes and corrugated surface is an efficient method of heat transfer improvement, since the referred manners break the boundary layer and improve the heat exchange. This paper aims to present an improved dual-flow parabolic trough collector (PTC). For this purpose, the effect of an absorber roof, a type of turbulator and a grooved absorber tube in the presence of nanofluid is investigated separately and simultaneously. Design/methodology/approach The FLUENT was used for solution of governing equation using control volume scheme. The control volume scheme has been used for solving the governing equations using the finite volume method. The standard k–e turbulence model has been chosen. Findings Fluid flow and heat transfer features, as friction factor, performance evaluation criteria (PEC) and Nusselt number have been calculated and analyzed. It is showed that absorber roof intensifies the heat transfer ratio in PTCs. Also, the combination of inserting the turbulator, outer corrugated and inner grooved absorber tube surface can enhance the PEC of PTCs considerably. Originality/value Results of the current study show that the PTC with two heat transfer fluids, outer and inner surface corrugated absorber tube, inserting the twisted tape and absorber roof have the maximum Nusselt number ratio equal to 5, and PEC higher than 2.5 between all proposed arrangements for investigated Reynolds numbers (from 10,000 to 20,000) and nanoparticles [Boehmite alumina (“λ-AlOOH)”] volume fractions (from 0.005 to 0.03). Maximum Nusselt number and PEC correspond to nanoparticle volume fraction and Reynolds number equal to 0.03 and 20,000, respectively. Besides, it was found that the performance evaluation criteria index values continuously grow by an intensification of nanoparticle volume concentrations.

Novel method to assess anisotropy in formability using DIC

In this study, a novel technique was developed to identify localized neck of a tensile sample based on the curvature of the surface that is expected to work with any metal in which a localized neck forms prior to fracture. Moreover, a MATLAB-based computational tool has been developed to conduct advanced mathematical computations and numerical analysis on data generated from uniaxial tensile test of DP980 steel coupled with Digital Image Correlation (DIC) based on the novel curvature method. The presented curvature technique is a geometry-based approach that uses the specimen's surface profile and groove geometry to detect localized necking, avoiding the limitations of strain-based methods in distinguishing between localized and diffuse necking. A detailed analysis was conducted on the accuracy of the onset and anisotropy of localized neck. The results of the study revealed that specimens fabricated with 30-degree orientation with respect to the Rolling Direction (RD) of the sheet metal, exhibit a higher level of total strain at the onset of the localized necking, indicating the influence of anisotropy on the material's behavior for DP980. Moreover, consistent R-values were observed among specimens with the same orientation with respect to the RD, exhibiting a rising trend of R-value for orientations from zero to 60-degree, followed by a decrease from 60 to 90-degree. Furthermore, the results exhibited a negative linear relationship between R-values and the magnitude of thinning strain.

A proof-of-concept study of a prototype needle that mitigates intraocular pressure rise following intravitreal injection

PurposeTo determine the feasibility of a prototype needle that enhances vitreous reflux (VR) to control intraocular pressure (IOP) in intravitreal injection (IVI).MethodsWe created an eye model to compare IVI using a standard 30-G needle with four different versions of a 30-G prototype needle with one to four surface grooves that enhanced VR. We injected 50, 70, and 100 µl saline through porcine sclera or 460-µm-thick rubber and measured the peak and 3-second pressure before we extracted the needle and measured the 10-second pressure.Results50-µl injection through sclera with the standard needle resulted in mean (SD) pressure of 58.6 (3.8) mmHg at peak, 52.8 (4.7) mmHg at 3 s, and 39.6 (18.0) mmHg at 10 s. The prototype needle lowered the pressure; four grooves resulted in mean (SD) pressure of 29.4 (5.6) mmHg at peak, 22.0 (3.7) mmHg at 3 s, and 7.2 (6.6) mmHg at 10 s. 70-µl and 100-µl injections through sclera with the standard needle resulted in mean (SD) pressure of 68.8 (3.6) and 86.0 (6.0) mmHg at peak. Similar to 50-µl injection, the prototype needle lowered the pressure for 70-µl and 100-µl injections. At 10 s, we observed varying leakage at the injection site for sclera but not for rubber.ConclusionsThe study provides proof of concept for a needle design for which surface grooves enhance VR and counteract the effect of IVI on IOP. The safety and efficacy of the prototype needle must be studied further in a clinical trial.

Siphon-based scalable and salt-resistant multistage thermal desalination system

Recent advances in thermal localization-based passive solar desalination provide a great opportunity for the economical generation of freshwater, particularly in regions with insufficient energy and water infrastructure. Yet, the capillary-assisted passive desalination systems with a high-water productivity flux (measured in Lm−2 h−1) suffer from the issue of performance degradation due to salt accumulation and the inability to be scaled up. In this work, we propose siphon-based supply of saline water over the evaporator that enables scale up of the desalination system to a size significantly higher than the capillary rise height of the hydrophilic evaporator while preventing salt accumulation on the evaporator. The composite siphon comprises insulating fabric wick and a metallic grooved surface for localizing heat to evaporate a thin layer of saline liquid over the evaporator. We perform heat and mass transfer analysis to show that the thermal-to-vapor efficiency depends on the inlet mass flow rate and air gap between the evaporator and the condenser. We propose a methodology to passively control the mass flow rate to maximize the thermal to vapor efficiency at different input heat flux and initial concentration of the brine. A grooved condenser avoids mixing of brine and the freshwater, even at air gaps as low as 2 mm. A siphon-assisted 10-stage desalination system with a footprint area 15 cm × 15 cm and an air gap of 2 mm is shown to have a high water productivity flux of ~5.73 Lm−2 h−1 from 3.5 wt% saline water at an applied heat flux 1000 W/m2, which increases to a record high distillate flux of ~6.23 Lm−2 h−1 and thermal to water collection efficiency of ~423 % for a 15-stage system. The ability of the desalination system to maintain a high-water productivity flux even when the evaporator area is increased by 4 times demonstrates its scalability to achieve higher desalinated water productivity rate.

Dynamic shape changes of dried pasta during cooking via designed surface grooves

The morphing of food during gastronomic treatments is of current interest not only for product innovation and unprecedented human-food sensory interaction but also for sustainable reasons because it would enable to increase the load saturation for food packages with several positive environmental impacts. A shape changing pasta during cooking has been achieved through designed grooves and protrusions on one side of the samples. However, a quantitative understanding of the effects of manufacturing and drying process on the shape morphing is still missing. Here, three pressures applied on the surface of the samples and three thicknesses of the sheeted dough have been analyzed for their effect on the dehydration kinetics of pasta, microstructure properties, water absorption and the kinetic of bending during cooking. Results proved the effectiveness of the proposed strategy to activate the morphing of dried pasta during cooking. The dehydration rates were primarily affected by the thickness of the sheeted dough while the applied pressure did not modify the dehydration kinetics of samples of 1.5 and 1 mm thick. 2D microCT images revealed that by using a constant pressure, the grooves were deeper as sheeted doughs were thick; the greater amount of dough permitted much more upward expansion between the teeth of the plastic stamp leading to higher protrusions/deeper grooves. The rehydration rate was mainly controlled by the height of the remaining layers below the grooves while the pressures applied did not affect the rate of the water absorption over time. The kinetic of bending during cooking was satisfactorily described by using a sigmoidal mathematical model. Results proved that the speed of bending was mainly affected by the thickness of the sheeted dough while the applied pressures affected the speed of bending only for the thinner samples of 1.5 and 1 mm thick while the thicker samples folded at the same speed with no changes among the pressure applied.

CFD-DEM coupled study of erosion resistance characteristics of ribbed walls

Industrial bulk material transfer systems are exposed to high erosion risk due to prolonged scouring by particle flow. In order to improve the erosion resistance of the system components, this study proposes a wear-resistant improvement scheme by adding square and triangular ribs on the wall surface. A coupled CFD-DEM method was used to analyse the abrasion characteristics of particle flow hitting the flat and ribbed wall surfaces at different particle incidence angles, particle velocities and particle volume fractions. The results show that square ribbed plate is more targeted to reduce the erosion ratio of the groove surface and transfer the risk to the ribs, whereas triangular ribbed plate provides an optimal balance between sacrificial velocity and erosion resistance of the ribbed structure; moreover, square ribbed plate is slightly more capable of transferring the maximum wear to the ribs to reduce the risk of perforation of the wall surface. As the particle velocity increased from 5 m/s to 25 m/s, the triangular ribbed plate reduced the erosion ratio by up to 45 %; both square and triangular ribbed plate groove surfaces reduced the maximum wear rate by about 65 % and 35 %, respectively. With the increase of particle volume fraction from 0.025 % to 0.125 %, the erosion ratios of the square and triangular ribbed plates decreased rapidly by up to 16 % and 73 %, respectively; the groove surface of the square ribbed plate decreased by about 63 % of the maximum wear rate, while the groove surface of the triangular ribbed plate decreased by up to 48 % of the maximum wear rate.

Influence of surface texture on pocket pairs lubrication performance of cylindrical roller bearings

PurposeThis paper aims to reveal the influence of the grooved texture parameters on the lubrication performance of circular pocket-roller pairs in cylindrical roller bearings.Design/methodology/approachIn this paper, the thermal elastohydrodynamic lubrication mathematical model of the grooved texture circular pocket-roller pair was established, the finite difference method and successive over-relaxation method were used to solve the model, the influence of texture quantity, texture depth and texture area ratio on circumferential bearing capacity, friction coefficient, maximum temperature rise, stiffness and damping of the circular pocket-roller pairs were analyzed.FindingsThe results show that texture quantity, texture depth and texture area ratio significantly influence the static and dynamic characteristics of circular pocket-roller pairs. The suitable surface groove texture parameters can dramatically improve the circumferential bearing capacity, reduce the friction coefficient, inhibit the maximum temperature rise and increase the stiffness and damping of the circular pocket-roller pairs.Originality/valueThe research in this paper can provide a theoretical basis for the optimization design of pockets in cylindrical roller bearings to reduce friction and vibration.

Photocatalytic and antibacterial activity properties of Ti surface treated by femtosecond laser–a prospective solution to peri-implant disease

Laser texturing seems to be a promising technique for reducing bacterial adhesion on titanium implant surfaces. This work aims to demonstrate the possibility of obtaining a functionally orientated surface of titanium implant elements with a specific architecture with specific bacteriological and photocatalytic properties. Femtosecond laser-generated surface structures, such as laser-induced periodic surface structures (LIPSS, wrinkles), grooves, and spikes on titanium, have been characterised by XRD, Raman spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of the titanium surfaces produced was tested based on the degradation effect of methylene blue (MB). The correlation between the photocatalytic activity of TiO2 coatings and their morphology and structure has been analysed. Features related to the size, shape, and distribution of the roughness patterns were found to influence the adhesion of the bacterial strain on different surfaces. On the laser-structurised surface, the adhesion of Escherichia coli bacteria were reduced by 80% compared to an untreated reference surface.

Nature-inspired ultrathin wood-based interfacial solar steam generators for high-efficiency water purification

Here, inspired from butterfly wing, novel hierarchical biomimetic structures composed of tunable nano-structured surfaces, rich micro/nanopores and aligned grooves from polythiophene decorated fir wood veneer have been developed to solve it. Nanowire-shaped and button-like nanostructured polythiophenes as light absorption enhanced materials were in situ grown on wood surface by adjustable vapor deposition process (PFW and CPFW). Meanwhile, wood veneer with reversed-tree structure has a unique aligned grooves surface from split tracheids, serving as the substrate for the nanostructured polythiophenes. These ultrathin wood-based solar steam generators (0.6 mm) stand as one of the thinnest reported self-floating photothermal materials based on wood. Meanwhile, high evaporation flux (1.42 and 1.48 kg·m−2·h−1) and solar-to-vapor efficiencies (88.5 % and 92.4 %) for PFW and CPFW are acquired under 1 sun irradiation. Their structure superiority boosting photothermal conversion performance has been further verified by COMSOL simulated results. The synthesized solar steam generator exhibits exceptional capabilities in seawater desalination and wastewater treatment, demonstrating fantastic application potential in water purification.

Study on the forming mechanism and evolutionary pattern of stagnant region in mechanical scratching

In this paper, a combination of theoretical modeling, finite element simulation, and experimental methods is employed to investigate the forming mechanism and evolutionary pattern of the stagnant region during mechanical scratching with a diamond wedge tool. The study is structured as follows: Firstly, a theoretical calculation model for the geometric parameters of the stagnant region on the formed groove surface is established based on the contact friction partition mechanism and slip-line field theory. The model indicates that the geometric parameters lB-sg, lV-sg, and ∆lsg of the stagnant region are determined by the length of the stagnant region lp-sg in the plastic flow plane and the transformation parameters. Secondly, the formation process of the stagnant region in mechanical scratching is investigated using an orthogonal cutting simulation model with a negative rake angle tool. The results reveal that the stagnant region is a plastic deformation region formed due to the geometrical characteristics of the negative front surface of the scratching tool and its excessive extrusion, which leads to the formation of adhesive friction within the material. Thirdly, the characteristics of the stagnant region are determined through scratching experiments. Compared to the material in the plastic flow region, the material within the stagnant region exhibits finer and denser microstructures, reduced surface hardening peaks and hardened layer depths, and significantly improved surface roughness. Finally, the evolutionary pattern of the stagnant region under the influence of scratching processing parameters is examined based on the theoretical calculation model of the geometric parameters and the scratching experiment. The findings indicate that as the wedge angle of the scratching tool decreases, the relief angle increases, the absolute value of the rotation angle around the Y-axis decreases, the scratching speed decreases, and the material’s plastic adherence improves, the PI/k value decreases, the lp-sg value increases, and consequently, the geometric parameters lB-sg, lV-sg, and ∆lsg of the stagnant region on the formed groove surface also increase. The deviation analysis of the geometric parameters of the stagnant region reveals a consistent trend between the theoretical and experimental values of lV-sg and ∆lsg, with maximum deviations of 15 μm and 4.13%, respectively. This study provides theoretical and experimental evidence for the establishment of the theoretical model of the stagnant region in mechanical scratching, the analysis of its forming mechanism, and the control of the stagnant region geometric parameters on the formed groove surface.

An Invitro Study to Evaluate the Retentive Properties of Metal Crowns on Various Surface Roughnesses of Abutments.

Background Restorative dentists frequently deal with the prosthesis coming loose after placing multiple crowns. The luting cementholds indirect restorations to the prepared tooth. However, the success of the restorations is impacted by mastication pressures and other undesired factors. Therefore, escape is required to increase the crown's life. Mechanical locking of the prepared tooth surface is one technique to address this issue, in addition to cement adherence, to extend the life of the restoration. Aims and objective Theobjective of the study was to evaluate the influence of surface roughness of prepared teeth on the retention of metal crowns. Methodology This in-vitro investigation was carried out on freshly extracted maxillary first premolars that were defect-free and had the same crown size. Using multiple grifts of varied coarseness, different surface roughness was created, allowing for the observation of an important factor like retention (black at 180-250 µm [micrometer], blue at 125-150 µm, green at 106-125 µm, red at 53-63 µm, yellow at 20-30 µm). Results IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. was used to perform the statistical analysis. Compounds were done before it began to guarantee that the study would have 80% power. There is a mean and a standard deviation for each quantitative variable. A one-way ANOVA was used for quantitative variables, and Tukey's post hoc analysis was conducted afterward. A probability value of less than 0.05 was used to determine statistical significance. According to the statistical findings, the prosthesis's retentive qualities improve as coarseness increases. Conclusion The resistance and retention form of the preparation is critical to the longevity of the prosthesis, based on the findings of the previously described study. Surface roughness, pins, slots, grooves, and other preparation modifications can enhance retention on the prepared tooth surface. The research findings indicate no need to polish the prepared tooth surface.

Dissecting the neuroprotective interaction between the BH4 domain of BCL-w and the IP3 receptor

BCL-w is a BCL-2 family protein that promotes cell survival in tissue- and disease-specific contexts. The canonical anti-apoptotic functionality of BCL-w is mediated by a surface groove that traps the BCL-2 homology 3 (BH3) α-helices of pro-apoptotic members, blocking cell death. A distinct N-terminal portion of BCL-w, termed the BCL-2 homology 4 (BH4) domain, selectively protects axons from paclitaxel-induced degeneration by modulating IP3 receptors, a noncanonical BCL-2 family target. Given the potential of BCL-w BH4 mimetics to prevent or mitigate chemotherapy-induced peripheral neuropathy, we sought to characterize the interaction between BCL-w BH4 and the IP3 receptor, combining "staple" and alanine scanning approaches with molecular dynamics simulations. We generated and identified stapled BCL-w BH4 peptides with optimized IP3 receptor binding and neuroprotective activities. Point mutagenesis further revealed the sequence determinants for BCL-w BH4 specificity, providing a blueprint for therapeutic targeting of IP3 receptors to achieve neuroprotection.

Polishing-induced skid resistance deterioration characteristics of grooved runway pavements

The effect of polishing on the skid resistance performance of grooved pavement surfaces has not been adequately addressed by researchers. This research conducted a laboratory polishing study to compare the skid resistance deterioration characteristics of ungrooved surfaces and grooved surfaces having the standard 6 x 6 x 38 mm (width x depth x center-to-center spacing) grooves. It was found that grooved surfaces received more severe polishing than ungrooved surfaces, and the initial skid resistance advantage of a grooved surface could be significantly reduced due to polishing during service. The findings suggest that even though the presence of grooves help to relieve hydrodynamic pressure when an aircraft moves on a wet grooved runway pavement at high speeds, the advantage of reducing hydroplaning and skidding risks would become less as the pavement’s service period increases. Therefore, the overall benefits of grooved pavements should be assessed at its polished state.

Structural basis for the H2AK119ub1-specific DNMT3A-nucleosome interaction

Isoform 1 of DNA methyltransferase DNMT3A (DNMT3A1) specifically recognizes nucleosome monoubiquitylated at histone H2A lysine-119 (H2AK119ub1) for establishment of DNA methylation. Mis-regulation of this process may cause aberrant DNA methylation and pathogenesis. However, the molecular basis underlying DNMT3A1−nucleosome interaction remains elusive. Here we report the cryo-EM structure of DNMT3A1’s ubiquitin-dependent recruitment (UDR) fragment complexed with H2AK119ub1-modified nucleosome. DNMT3A1 UDR occupies an extensive nucleosome surface, involving the H2A-H2B acidic patch, a surface groove formed by H2A and H3, nucleosomal DNA, and H2AK119ub1. The DNMT3A1 UDR’s interaction with H2AK119ub1 affects the functionality of DNMT3A1 in cells in a context-dependent manner. Our structural and biochemical analysis also reveals competition between DNMT3A1 and JARID2, a cofactor of polycomb repression complex 2 (PRC2), for nucleosome binding, suggesting the interplay between different epigenetic pathways. Together, this study reports a molecular basis for H2AK119ub1-dependent DNMT3A1−nucleosome association, with important implications in DNMT3A1-mediated DNA methylation in development.