Disk Shape Research Articles

Experimental investigation on the effect of grain size of granitic rocks on the fracture roughness and toughness

The fracture surface characterization, such as the fracture roughness, is essential to flow and heat transport through the fracture in the geothermal, oil, and gas reservoirs stimulation by hydraulic fracturing. This research presents an experimental approach to assess the correlation between the fracture roughness and mode I fracture toughness (KIc) of the granitic rock with different grain sizes, which is crucial in geothermal reservoirs. Three types of granite with the same mineralogical compositions but fine, medium, and coarse-grained structures were selected and prepared. Fracture toughness values were measured using a novel specimen called ENDB (Edge Notched Disc Bend), in which a cracked disc shape specimen was loaded in three-point bending. The photogrammetric method was used to estimate the value and distribution of surface roughness after ENDB testing and investigate the relationship between fracture morphology and fracture toughness. Based on the experiments, a clear correlation between the roughness and fracture toughness was observed in the three investigated granite types with different grain sizes. The FPZ around the crack tip, tortuosity, intergranular, and transgranular cracks were examined to study the effect of grain size on fracture toughness and roughness precisely. The results show that by increasing the grain size, KIc and surface roughness increased. The results also showed that the roughness parameter for the three types of rocks in the direction of the crack growth path is greater than the direction perpendicular to the crack growth path.

Highly sensitive optical fibre Bragg grating contact pressure sensor embedded in a polymer layer: Modelling and experimental validation

This paper discusses mathematical modelling and experimental validation of a highly sensitive optical fibre Bragg grating (FBG) contact pressure sensor developed for healthcare applications. Bare FBGs are not very sensitive to pressure (∼3 × 10−3 nm/MPa) but this can be increased by embedding the FBG in a polymer layer which acts as transducer to convert transverse load (pressure) applied to an axial strain, measured by the FBG sensor. The pressure sensitivity of the FBG sensor depends on the mechanical and physical properties such as Young’s modulus, shape and size of the polymer. A finite element analysis (FEA) model is developed to optimise the design parameters of the FBG sensor in order to achieve a high sensitivity. A transfer matrix mathematical formulism is then used to relate the reflection spectrum of the FBG to the strain experienced. Three different shapes, three different sizes and three different polymer materials with different Young’s moduli have been simulated and their wavelength sensitivities related to the transverse pressure. According to the simulation results, the pressure sensitivity of a bare FBG can be increased ∼ 270 times (0.8179 nm/MPa) by selecting an FBG of 3 mm length, embedding it at the horizontal centre of a polymer layer of Young’s modulus of 20 MPa, in the shape of a circular disc with a diameter 5.5 mm and thickness of 1 mm.

Effect of Beverage Solutions on Surface Roughness of PEEK CAD –CAM, 3D Printing Denture Base and Heat Cure Acrylic Resin Denture Base Materials

The Aim: The aim of this research was to investigate how distilled water, tea, coffee, and cola affected the surface roughness of poly ether ether ketone CAD-CAM, 3D printing, and heat cure acrylic resin denture bases at specific intervals (6 ,12days). Materials and Methods: Disk shape 10 mm (diameter) ×2 m m (thickness), manufactured from materials used which were PEEK, 3D printing and heat cure acrylic resin. Total number of samples are n= (75) samples, control samples not immersed in beverage media n= 15, experimental samples immersed in beverage solutions (distilled water, tea, coffee and cola) n=60 for evaluating the surface roughness at (6, 12 and 24 days) .Then all collecting data were statically analyzed by spss v ersion 25, by means of descriptive statistics, analysis of variance (ANOVA) and duncan multiple range tests at p ≤ 0.05. The Results: The results revealed a significant increase in surface roughness in all beverage solutions at p ≤ 0.0 5. Conclusions: All beverage solutions had a negative effect on surface roughness of all experimental materials, the surface roughness increased. cola had the most aggressive effect followed by coffee then tea and distilled water have the least ef fect.

Results of acceptance tests of the disk plow for tillage in agriculture

Soil is the main natural resource for agriculture. All vital crops necessary for humanity and livestock are cultivated in it. As a result, a lot of research is being done on the creation of new technical tools and technologies for agriculture, including soil cultivation. The following years, disk plows, the working tools are in the shape of a spherical disk, have been widely used for plowing all over the world. Due to the fact that in addition to the forward movement of the working parts, the disc plows have less traction resistance than rotary plows and work without getting stuck in weeds and plant residues. In addition, disk plows are simpler in design than rotary plows, require less care and maintenance, as the cutting blades wear less and are constantly self-sharpening (due to rotation), and due to their length (compared to plow plows), disks work several times longer than plows with plowshares. The developed disc plow provides better soil compaction than a tipping plow, i.e. the number of fractions less than 50 mm in the area of its passage was 3.1-4.3 percent more, and the number of fractions more than 100 mm was 2.0-3 decreased by 6 percent.

Anatomic Characteristics of Ultrasound Imaging of the Temporomandibular Joint at Rest and in Various Jaw Positions in Healthy Individuals: A Descriptive Study

This study examined the temporomandibular joint (TMJ) anatomy and biomechanics using Ultrasound (US) imaging to examine the TMJ anatomy at rest and in various positions of normal jaw movement in healthy individuals. A secondary aim was to describe US imaging parameters used to visually observed the TMJ. The study included 11 participants (8 M and 3 F; 22.9 ± 3.4 yrs) University with no history of TMJ problems. All 11 participants had some atypical anatomy (flat mandibular head, altered articular disc shape, displacement or deformation of the disc during movement) while using US imagining. No participants had current pain or dysfunction and none met the Diagnostic Criteria for Temporomandibular Dysfunction (DC-TMD) classifications for the condition. Most participants denied symptoms during testing, although one participant did have pain with retrusion and another had popping without pain. This study in part has added to the growing interest of using US imaging as modality to investigate the anatomy and biomechanics of the TMJ and the relationship to TMD. Future studies are warranted to examine TMJ anatomy and biomechanics via US imaging in order to provide further recommendations on the techniques and settings for the modality for the end-user.

Can a magnetic resonance imaging (MRI) of the temporomandibular joint predict disc perforation?

Background Magnetic resonance imaging (MRI) is widely regarded as the gold standard for diagnosing internal derangement; however, its accuracy in detecting disc perforations varies. Objectives: 1) identify MRI features correlating with disc perforation, 2) identify preoperative variables correlating with disc perforation, and 3) develop a predictive model to ascertain the presence of disc perforation. Materials and Methods This cohort study involved 92 patients who underwent arthroscopic surgery to identify associated variables. Arthroscopically verified disc perforation was considered the primary predictor variable, while MRI interpretation of disc perforation served as the primary outcome variable. Demographic data, patient signs, and symptoms were treated as covariates. Statistical analyses were conducted at a significance level of 5%. Logistic regression models were employed to predict disc perforation, and diagnostic accuracy was assessed using ROC curves. Results Among the 155 joints analyzed (92 patients: 135 females, 20 males), MRI interpretations did not significantly correlate with verified disc perforation (p < 0.218), demonstrating 14.3% sensitivity and 92.5% specificity. Age, symptomatic onset, joint noise type, osteoarthritis diagnosis, altered disc shape, and Wilkes classification exhibited significant associations (p < 0.05). A logistic regression model utilized associated variables for predicting disc perforation. Risk factors included symptom onset time, joint crepitus, osteoarthrosis diagnosis by MRI; joint click was considered protective. Conclusion The model demonstrated high diagnostic accuracy (AUC of 0.836, 95% CI 0.76–0.91). While MRI interpretation was unreliable, our model accurately predicted disc perforation. Identification of these factors could inform surgical decisions

200A 게이트 밸브의 디스크 형상개선에 따른 진동감쇠 효과

200A 게이트 밸브의 디스크 형상개선에 따른 진동감쇠 효과

Experimental investigations of DGEBA epoxy resin dispersed liquid crystal polymer systems for the development of new electronic devices

The DGEBA: Diglycidyletherbisphenol A and Liquid Crystal (4′-Pentyl-4-Biphenylcarbonitrile (5CBLC)) have been used to fabricate the so-called DGEBA epoxy dispersed 5CB liquid crystals (DED5CBLC). The XRD study's findings suggest that 5CBLC fillers can be used to change the properties of DGEBA epoxy without significantly changing its structure. Results from optical measurements reveal that the amount of 5CBLC filler added to the new disc shape system can adjust the band gap. This provides a way to design disc shape systems with desired optical properties. A promising correlation exists between optical linear susceptibility, third nonlinear optical, and nonlinear refractive index with 5CBLC filler in the DGEBA epoxy matrix. This correlation is since all three of these properties are told to the electronic structure of the DGEBA epoxy matrix. AC-impedance and AC conductivity properties of DED5CBLC disc shape systems filled with various wt% CB molecules have been good for adding 5CBLC content and applied field frequency. The results show that the AC conductivity of the composite spreads with rising wt% 5CBLC filler content and frequency. The continuous Jonscher fitting theoretical curve can be used to characterize the relaxation process and predict the system's electrical properties at different frequencies. The shrink in impedance directs that the composite substance befalls more conductive.

Evaluation of Low- and Intermediate-Temperature Cracking Performance of Fiber-Reinforced Asphalt Mixtures

This study was conducted to assess the impact of aramid fiber reinforcement on the fatigue and thermal cracking performance of asphalt mixtures at intermediate and low temperatures, respectively. The study also involved evaluating the experimental consistency and ranking fiber-reinforced asphalt mixtures (FRAMs) based on their performance. One aggregate (diabase stone), one binder type (PG 76-22), and two combinations of aramid fibers, added at different dosages, were used to produce three FRAMs. These fibers included polyolefin/aramid (PFA) fibers at 0.05% dosage by mix weight and Sasobit-coated aramid (SCA) fibers at 0.01% and 0.02% dosages. An unreinforced (control) mix was also produced without any reinforcement. All mixtures were produced at a batch plant by keeping their binder content constant (at 5.5%). The manufacturer recommended dry and wet mixing times were used for better fiber distribution and represent actual mixing conditions. The laboratory performance of plant-produced FRAMs was assessed to characterize the low- and intermediate-temperature cracking performance. The indirect tension asphalt cracking test, semi-circular bend test, three-point bending beam tests, and uniaxial fatigue tests were performed at intermediate temperature; the disk shape compact tension test and thermal stress restrained specimen test tests were performed at low temperature. Fibers were successful at improving the fatigue cracking of asphalt mixtures based on intermediate-temperature testing results. In addition, fiber reinforcement, regardless of dosage and combination, showed improvements in low-temperature (thermal) cracking performance. Furthermore, based on ranking analysis for selected performance indicators from each experiment, the SCA 0.02% reinforced mix on average showed the highest cracking resistance.

Viscous heating as the dominant heat source inside the water snowline of V883 Ori

ABSTRACT FU Orionis-type objects (FUors) are embedded protostars that undergo episodes of high accretion, potentially indicating a widespread but poorly understood phase in the formation of low-mass stars. Gaining a better understanding of the influence exerted by these outbursts on the evolution of the surrounding protoplanetary disc may hold significant implications for the process of planet formation and the evolution of disc chemistry. The heating due to outbursts of high accretion in FUors pushes the snowlines of key volatiles farther out in the disc, so they become easier to observe and study. Among the known FUors, V883 Ori is of particular interest. V883 Ori was the first FUor to show indirect evidence of a resolvable snowline beyond 40 au. By introducing a radial-dependent model of this source including viscous heating, we show that active heating is needed to reproduce the steep thermal profile of dust in the inner disc of V883 Ori. Our disc modelling combines the effect of stellar irradiation and the influence on the disc shape caused by the outburst of accretion. The accuracy of our model is tested by comparing synthetic Atacama Larga Millimeter Array images with continuum observations of V883 Ori, showing that the model successfully reproduces the 1.3 mm emission of V883 Ori at high spatial resolution. Our final predictions underline the importance of viscous heating as a predominant heat source for this type of object, changing the physical conditions (shape and temperature) of the disc, and influencing its evolution.

RANCANG BANGUN GENERATOR MAGNET PERMANEN FLUKSI AKSIAL SINGLE STATOR SINGLE ROTOR

Permanent magnet synchronous generator is one type of generator that is widely used for small-scale power generation, because it can be operated at low speed, so it does not require a gearbox in its operation. This paper proposes the manufacture of a low speed axial flux permanent magnet synchronous generator that can be used for small-scale electric power generation. The generator is designed in the form of a single stator single rotor. The generator stator is designed using fiberglass as the holder for the nine coils, while the rotor is designed in a disc shape using aluminum as the holder for the Neodymium N52 permanent magnet. The generator design was validated through Finite Element Analysis simulation using solidwork and tested through experiments using an induction motor as the driving force. Tests were carried out with varying air gaps and rotational speeds. The experimental results show that the generator can produce a voltage of 15.4 Volts when the generator is rotated at a speed of 500 rpm. The generator can also produce a maximum power of 400 Watts with an air gap of 2 mm

F. prausnitzii-derived extracellular vesicles attenuate experimental colitis by regulating intestinal homeostasis in mice

BackgroundEmerging evidence has shown that extracellular vesicles (EVs) derived from gut bacteria play a crucial role in microbiota-host interactions. Here, we aimed to evaluate the attenuating effect of EVs derived from a reduced commensal bacterium, F. prausnitzii (Fp-EVs), in inflammatory bowel disease (IBD) on dextran sulfate sodium (DSS)-induced colitis in mice.ResultsFp-EVs isolated by ultracentrifugation and typically exhibited a double concave disc shape with an average diameter of 172 nm. Fp-EVs treatment reduced DSS-induced weight loss, disease activity index (DAI) score, colon length shortening, histological damage, neutrophil infiltration and increased intestinal epithelial apoptotic cells in DSS-induced colitis mice. Fp-EVs upregulated the protein expression of zona occludens (ZO)-1 and Occludin and increased the ratio of Tregs in the colon tissue of colitis mice. Furthermore, Fp-EVs downregulated the expression of the proinflammatory cytokines interleukin-1β (IL-1β), IL-2, IL-6, IL-12a, IL-17a, Interferon-γ (IFN-γ), tumor necrosis factor - α (TNF-α), granulocyte-macrophage colony stimulating factor (GM-CSF) and upregulated the anti-inflammatory cytokines IL-4, IL-10, and transforming growth factor β (TGF-β) in DSS-treated mice. Moreover, Fp-EV treatment markedly reduced the phosphorylation of these proteins Nuclear factor-κB (NF-κB) and Mitogen activated protein kinase (MAPK), and regulated the expression of nuclear factor erythroid 2-related factor (Nrf2) and heme oxygenase-1 (HO-1).ConclusionOur findings revealed that Fp-EVs attenuated DSS-induced colitis by modulating the intestinal mucosal barrier function and immunological profile. Our findings reveal that Fp-EVs attenuate DSS-induced colitis by modulating intestinal mucosal barrier function and the immunological profile.

Designing a simple and suitable laboratory test specimen for investigating the general mixed mode I/II/III fracture problem

A novel test specimen was designed for experimental investigations of pure and mixed mode fracture. This novel test configuration is called “modified edge notched disc bend” (M-ENDB) specimen. The M-ENDB specimen has a circular disc shape with an edge crack along its diameter that is loaded using asymmetric three-point bending. Different fracture parameters including: stress intensity factors (SIFs), geometry factors, T-stress, biaxiality ratio (BR), and out-of-plane constraint factor (Tz) were determined for the suggested disc bend specimen using the extensive finite element (FE) analyses. According to the obtained results, the proposed specimen can present all combinations of mode mixities, including pure modes I, II, and III as well as mixed-mode I/II, I/III, and I/II/III deformations. Afterwards, a large number of pure and mixed-mode fracture toughness experiments were carried out on polyurethane (PUR) foam to examine the capabilities of the suggested M-ENDB specimen. Fracture path, fracture surface, fracture toughness, work of fracture, and critical T-stress of broken foams under general mixed mode conditions were investigated. Mixed mode I/II/III fracture toughness value was smaller than the pure mode I fracture toughness (KIc) value showing the weakness of brittle materials against multi-axial fracture compared to pure tensile type fracture.

Magnetic Nanoparticles with Fe-N and Fe-C Cores and Carbon Shells Synthesized at High Pressures.

Nanoparticles of iron carbides and nitrides enclosed in graphite shells were obtained at 2 ÷ 8 GPa pressures and temperatures of around 800 °C from ferrocene and ferrocene-melamine mixture. The average core-shell particle size was below 60 nm. The graphite-like shells over the iron nitride cores were built of concentric graphene layers packed in a rhombohedral shape. It was found that at a pressure of 4 GPa and temperature of 800 °C, the stability of the nanoscale phases increases in a Fe7C3 -> Fe3C -> Fe3N1+x sequence and at 8 GPa in a Fe3C -> Fe7C3 -> Fe3N1+x sequence. At pressures of 2 ÷ 8 GPa and temperatures up to 1600 °C, iron nitride Fe3N1+x is more stable than iron carbides. At 8 GPa and 1600 °C, the average particle size of iron nitride increased to 0.5 ÷ 1 μm, while simultaneously formed free carbon particles had the shape of graphite discs with a size of 1 ÷ 2 μm. Structural refinement of the iron nitride using the Rietveld method gave the best result for the space group P6322. The refined composition of the samples obtained from a mixture of ferrocene and melamine at 8 GPa/800 °C corresponded to Fe3N1.208, and at 8 GPa/1650 °C to Fe3N1.259. The iron nitride core-shell nanoparticles exhibited magnetic behavior. Specific magnetization at 7.5 kOe of pure Fe3N1.208 was estimated to be 70 emu/g. Compared to other methods, the high-pressure method allows easy synthesis of the iron nitride cores inside pure carbon shells and control of the particle size. And in general, pressure is a good tool for modifying the phase and chemical composition of the iron-containing cores.

Self-propulsion of an elliptical phoretic disk emitting solute uniformly

Self-propulsion of chemically active droplets and phoretic disks has been studied widely; however, most research overlooks the influence of disk shape on swimming dynamics. Inspired by experimentally observed prolate composite droplets and elliptical camphor disks, we employ simulations to investigate the phoretic dynamics of an elliptical disk that emits solutes uniformly in the creeping flow regime. By varying the disk's eccentricity$e$and the Péclet number$Pe$, we distinguish five disk behaviours: stationary, steady, orbiting, periodic and chaotic. We perform a linear stability analysis (LSA) to predict the onset of instability and the most unstable eigenmode when a stationary disk transitions spontaneously to steady self-propulsion. In addition to the LSA, we use an alternative approach to determine the perturbation growth rate, illustrating the competing roles of advection and diffusion. The steady motion features a transition from a puller-type to a neutral-type swimmer as$Pe$increases, which occurs as a bimodal concentration profile at the disk surface shifts to a polarized solute distribution, driven by convective solute transport. An elliptical disk achieves an orbiting motion through a chiral symmetry-breaking instability, wherein it repeatedly follows a circular path while simultaneously rotating. The periodic swinging motion, emerging from a steady motion via a supercritical Hopf bifurcation, is characterized by a wave-like trajectory. We uncover a transition from normal diffusion to superdiffusion as eccentricity$e$increases, corresponding to a random-walking circular disk and a ballistically swimming elliptical counterpart, respectively.

Impact of the Accretion Disk Thickness on the Polarization of the Thermal Emission from Stellar Mass Black Holes

The Imaging X-ray Polarimetry Explorer, launched in 2021 December, enables precision measurements of the energy-dependent polarization of the X-ray emission from stellar mass and supermassive black holes. In this paper, we study the impact of the accretion disk geometry on the polarization of the thermal emission of mass-accreting stellar-mass black holes. We present a ray-tracing code that allows us to predict how the X-ray polarization energy spectra change as we dial up the thickness of the accretion disk from a geometrically thin accretion disk to a torus-shaped geometrically thick accretion disk. The results show that thicker disks can produce higher polarization degrees as the thick disk geometries lead to a larger fraction of X-rays reflecting off portions of the disk. We study the observational degeneracies between the disk shape on the one hand and the black hole spin and disk inclination on the other hand. We conclude with a discussion of the implications of our studies for black hole spin measurements.

Flexural strength and Vickers hardness of milled and 3D-printed resins for provisional dental restorations

Various forms of temporary resins are offered on the market; however, the properties of temporary resins obtained by milling and 3D printing have not been fully examined. This study aimed to compare the flexural strength and Vickers hardness of milled and 3D-printed resins. Methods: Three resins were tested: Evolux PMMA (milled resin), Cosmos Temp (3D-printed resin), and Structur 2 SC (bis-acrylic resin, group control). Specimens were prepared with rectangular shapes (n = 12) for flexural strength measurements and disc shapes (n = 9) for Vickers hardness tests. Flexural strength tests were performed at a crosshead speed of 0.75 mm/min, and the Vickers hardness was measured under a load of 20 N for 10 s. The obtained data were subjected to the Kruskal–Wallis test. Results: A significant difference (p < 0.05) in flexural strength was observed among the three sample groups: Evolux PMMA (111.76 MPa), Structur 2 SC (87.34 MPa), and Cosmos Temp (56.83 MPa). No significant difference (p < 0.05) was observed between the Vickers hardness values of Structur 2 SC (33.37 VHN) and Evolux PMMA (29.11 VHN); however, both materials were statistically superior to Cosmos Temp (10.90 VHN). Conclusion: While the mechanical properties of the milled resin were superior or similar to those of the bisacrylic resin, the 3D-printed resin was statistically inferior to both the milled and bis-acrylic resins.

Deep Optic Nerve Head Morphology in Tilted Disc Syndrome and Its Clinical Implication on Visual Damage.

To study deep optic nerve head (ONH) morphology in tilted disc syndrome (TDS) and identify factors associated with retinal nerve fiber layer (RNFL) defect. In patients with TDS, we evaluated the optic disc shape using the Bruch's membrane opening (BMO)-anterior scleral canal opening (ASCO) offset and measured the border tissue (BT) length, depth, and angle in the direction of the tilt, using radial ONH optical coherence tomography (OCT). We compared the parameters between the TDS groups with and without RNFL defects. Twenty-one eyes had no glaucomatous RNFL defect, and 38 eyes had a glaucomatous RNFL defect. The group with RNFL defects had a higher baseline IOP, larger tilt axis of BMO-ASCO optic disc margin (76.4° ± 14.5° vs. 87.9° ± 15.4°, P = 0.012), larger BMO-lamina cribrosa insertion (LCI) angle (25.6° ± 9.3° vs. 43.6° ± 15.2°, P < 0.001), and more lamina cribrosa (LC) defects (4.3% vs. 30.6%, P = 0.028) than without RNFL defects. The tilt axis and BMO-LCI angle were significant factors after adjusting for baseline IOP and LC defect. The BMO-LCI angle had excellent diagnostic power for glaucomatous RNFL defect in TDS, similar to the visual field mean deviation. OCT-based large deep ONH BT angle and tilt axis were factors associated with the presence of RNFL defects in TDS. The results suggest a mechanism of RNFL defect associated with structural ONH deformation. Further investigations are warranted to understand the role of ONH structures in a general population with and without optic disc tilt.

Thermal Field Simulation and Thermal Capacity Influence Factor Analysis of Disc Brake Based on Thermal-structure Coupling

The matching and heat dissipation capacity of the brake have an important impact on the braking performance of the vehicle. During braking, most of the driving kinetic energy of the vehicle is converted into the internal energy of the brake disc through friction heat generation, resulting in a quick rise in the temperature of the brake disc, thus causing a complex thermal-solid coupling problem. This paper takes the disc brake of a certain vehicle as the analysis object, establishes the finite element model of the disc brake through hypermesh, and analyzes the distribution characteristics of the contact pressure between the friction pad and the brake disc under clamping and torsion braking behaviors. A thermal-solid coupling simulation analysis method considering the actual heat flow and heat transfer boundary of the brake disc is proposed. Compared with the temperature field of the bench test, the simulation accuracy reaches 97%. Finally, three types of brake discs with point rib, rotation rib and straight rib are designed, and the influence of brake disc thickness, shape and number of ventilation rib on the thermal capacity of brake disc is analysed. It provides guidance for the structural design of brake discs and can replace partial tests and shorten the brake disc development cycle.

BaTiO3/Epoxy Resin Nanocomposites as Flexible Energy Storage Devices

In this work, nanocomposites between the epoxy resin and barium titanate (BT) were prepared in order to use as flexible energy storage devices. The epoxy resin and BT phase were homogeneously mixed and cast into a disk shape. Phase formation and chemical properties of these nanocomposites were identified via XRD and FTIR methods, respectively. Frequency dependence of dielectric properties for all samples was measured by LCR meter. The polarization hysteresis loops were also investigated in order to calculate the energy density of materials. From the results, it was found that the dielectric constant and loss of these nanocomposites are independent of frequency and the εr and tanδ values tend to increase with increasing BT amount. Moreover, after adding 50% of BT into the system, the energy density of nanocomposites is increased by five times compared with the pure epoxy resin while the energy loss density sharply decreases. The dielectric properties and the energy density of BT/epoxy resin nanocomposites change with BT content and strongly depend on porosity and the distribution of BT nanoparticles.