Types Of Disks Research Articles

Extinction and coexistence in a binary mixture of proliferating motile disks.

A binary mixture of two-different-size proliferating motile disks is studied. As growth is space limited, we focus on the conditions such that there is a coexistence of both large and small disks, or dominance of the larger disks. The study involves systematically varying some system parameters, such as diffusivities, growth rates, and self-propulsion velocities. In particular, we demonstrate that diffusing faster confers a competitive advantage, so that larger disks can in the long time coexist or even dominate the smaller ones. In the case of self-propelled disks, a coexistence regime is induced by the activity where the two types of disks show the same spatial distribution: both particles are phase separated or both are homogeneously distributed in the whole system.

In Vitro Study of the Proliferation of MG63 Cells Cultured on Five Different Titanium Surfaces.

Five types of titanium discs placed in contact with osteoblast cultures of osteosarcomas were studied. The materials had different roughness. Scanning electron microscopy (SEM) photos were taken before the in vitro culture to analyze the surfaces, and at the end of the culturing time, the different gene expressions of a broad pattern of proteins were evaluated to analyze the osteoblast response, as indicated in the scientific literature. It was demonstrated that the responses of the osteoblasts were different in the five cultures in contact with the five titanium discs with different surfaces; in particular, the response in the production of some proteins was statistically significant. The key role of titanium surfaces underlines how it is still possible to carry out increasingly accurate and targeted studies in the search for new surfaces capable of stimulating a better osteoblastic response and the long-term maintenance of osteointegration.

Percolation connectivity in deposits obtained usingcompetitive random sequential adsorption of binarydisk mixtures

Connectedness percolation phenomena in the two-dimensional (2D) packing of binary mixtures of disks with different diameters were studied numerically. The packings were produced using random sequential adsorption (RSA) model with simultaneous deposition of disks. The ratio of the particle diameters was varied within the range D=1-10, and the selection probability of the small disks was varied within the range 0-1. A core-shell structure of the particles was assumed for the analysis of connectivity. The packing coverages in a jamming state for different components, connectivities through small, large and both types of disks, the behavior of electrical conductivity were analyzed. The observed complex effects were explained accounting for the formation of conductive "bridges" from small disks in pores between large disks.

Remaining lifespan prediction on multiple types of hard disks under conditions of data imbalance

Most of the previous regression models for predicting the remaining useful life (RUL) of hard disks primarily focused on failure data obtained through SMART monitoring. However, models that only considered failure data were not accurate enough. In order to address the issue of imbalanced sample quantities in different categories within the dataset, this paper proposes a method for predicting the RUL of hard disks under imbalanced conditions. It takes into account the imbalance issues in both SMART failure data and healthy data, as well as the imbalance in monitoring data attributes between hard disk drives and solid-state drives. The paper improves upon the traditional Transformer time series model and constructs a comprehensive and unified model for the RUL of hard disks across multiple categories. The proposed model achieves an RMSE score of 3.325, and has 66 % in MAE improved to the conventional models. The proposed model has promising prospects for future applications in predicting the remaining life of hard disks.

Improving the performance of bentonite-free water-based mud with lignin-based biopolymer

Various drilling problems are associated with bentonite utilization in water-based muds, including formation damage, reduced production rate and overall cost. Various alternative solutions in terms of bio and synthethic based polymers have been tested to replace bentonite. However, due to their higher costs and availability, industry is looking for ecofriendly alternatives to overcome this issue. This work aims to utilize a lignin-based polymer (BioDrill FM400) for the formulation of bentonite-free mud blends with various dosages. The rheological and filtration properties were examined using the API standard procedures both at standard and high-temperature conditions. Seven mud blends with various dosages of the additive (0-12 ppb) were prepared, and mud’s plastic viscosity, yield point and gel strength were measured using viscometer. Similarly, mud filtration characteristics were assessed both with API and HPHT filterpress. Three types of rock disks (0.25" thick x 2.5" in diameter) were utilized to mimic the actual pore plugging mechanism. The rheological findings showed that the PV, YP and GS were significantly improved. On the other hand, the filtrate volume and filtercake thickness were reduced by 63 and 42% for the Bandera Brown disk sample. The current formulation is useful in drilling the payzone section of the wellbore.

Agronomic performance of disc chain harrow as a conservation agriculture tool for a one-step cover crop termination and seedbed preparation

Summary Cover crops and conservation soil tillage are reconsidered in cropping systems for their several agronomical and ecosystem services. In this frame, an important role is played by cover crop termination and seedbed preparation, which are crucial for a timely and successful establishment of the following cash crop. This work was aimed at testing a disc chain harrow for terminating a cover crop of hairy vetch and preparing a seedbed for soybean and defining its operational characteristics. A total of three trials were carried out to (1) compare two types of discs in two different front + rear combinations and two different working speeds (8 vs. 14 km h−1) in terms of efficacy of hairy vetch termination; (2) evaluate the seedbed preparation by the disc chain in terms of soybean establishment as a following cash crop; (3) evaluate operational characteristics (working speed, fuel consumption, absorbed power, etc.) of the disc chain at the two different speeds. Results demonstrate that the disc chain is a valid tool for cover crop termination and seedbed preparation in a conservation tillage approach. The quality of work was affected by the type of disc and the working speed. The disc chain showed good operating performance, with low mechanical pulling force, low energy requirement for traction, and low fuel consumption as compared to alternative conservation practices for cover crop termination and/or shallow soil tillage.

Desempenho de discos e anéis de semeadoras submetidos a temperaturas crescentes

Abstract The objective of this work was to evaluate the effect of temperature on disks and rings for seeders and the consequences for the performance of seed distribution. The treatments consisted of the heating of three types of disks and rings for seeders at 30, 40, 50, 60, 70, 80, 90, and 100°C, with four replicates. The evaluated variables were: fitting to the base of the seeder, thickness, diameter, and quality of seed distribution (failed, multiple, and acceptable spacings). There is no significant deformation in the disks and rings for the analyzed variables, and the performance of the longitudinal seed distribution is maintained at all temperatures.

Electromagnetic and Thermal Properties of HTS Bulk Combined With Different Ferromagnetic Structures Under Pulsed Field Magnetization

Pulsed field magnetization (PFM) is considered as the most effective method for magnetizing high temperature superconducting (HTS) bulks. Applying ferromagnetic materials around HTS bulks during PFM can increase their trapped field. This work proposes four ferromagnetic structures (disk, bottom ring, side ring, and bowl types) combined with HTS bulk. The trapped field and temperature are calculated in the HTS bulk with different ferromagnetic structures. The results show that the bowl type has the most significant ability to capture the magnetic field, while the bottom ring type has the smallest one. Compared with the trapped field of single bulk, the trapped field of the bowl type is increased by about 24% under the same PFM condition, and the temperature rise is also significantly decreased. In addition, the effects of different thicknesses of the ferromagnet on the trapped field and maximum temperature of bulk are also investigated. As the thickness of the ferromagnetic structure enlarges, the maximum temperatures of the disk and bottom ring increase, while the side ring and the bowl decrease.

Orientation of flake pigments in injection-molded polymer: Numerical simulation and its application to appearance prediction

A particle-level simulation of flake pigment orientation in injection molding was proposed to predict appearance defects caused by disturbed flake orientations. The effects of fountain flow and resin solidification were considered in order to reproduce the formation process for the orientation near the product surface, which has a large impact on the product appearance. In addition, an efficient method using a reverse-time calculation to predict the orientation in a surface layer was developed. The proposed method was verified by applying it to two types of center-gated disks, with different numbers of obstacles consisting of a hole and a thin-walled area, which were injection molded using polypropylene and aluminum flakes. For both disks, the proposed simulation reasonably predicted the location of the flow line defects generated downstream of the obstacles. We also performed an X-ray micro-computed tomography analysis to reveal the characteristic orientation distribution in the flow line.

Designs of Corrosion Modules for Long-Term Corrosion Tests of Canister Materials in Aerobic and Anaerobic Underground Water

Corrosion modules simulating the engineered barrier system were designed in this study for long-term-corrosion (LTC) testing of canister materials under aerobic and anaerobic conditions. The LTC module for aerobic conditions was designed as a bath-type container with flowing underground water extracted from the Korea Underground Research Tunnel. Five types of metallic disks, that is, rolled Cu, Type 304 stainless steel (SS), Titanium Grade 2 (Ti-G2), cast iron (CI), and Cu coating, were embedded into bentonite and maintained at different temperatures. After 3 years of testing under aerobic conditions, the corrosion rates of CI and Cu were estimated to be 1.9 μm/year and 550 nm/year, respectively. The SS and Ti-G2 exhibited a better corrosion rate of 6 nm/year. The LTC module for anaerobic conditions was developed in a vessel-type cylindrical container to allow it to settle in the boreholes. Four coin-shaped disks of each metal were embedded in bentonite, which was subsequently stacked in the cylindrical vessel. The vessels were placed in boreholes at a depth of 300 m. The Cu corrosion rate after 6 months of LTC testing under anaerobic conditions was 280 nm/year. Longer LTC tests will provide a more exact corrosion rate.

Hard Disk Failure Prediction Based on Blending Ensemble Learning

As the most widely used storage device today, hard disks are efficient and convenient, but the damage incurred in the event of a failure can be very significant. Therefore, early warnings before hard disk failure, allowing the stored content to be backed up and transferred in advance, can reduce many losses. In recent years, an endless stream of research on the prediction of hard disk failure prediction has emerged. The detection accuracy of various methods, from basic machine learning models, such as decision trees and random forests, to deep learning methods, such as BP neural networks and recurrent neural networks, has also been improving. In this paper, based on the idea of blending ensemble learning, a novel failure prediction method combining machine learning algorithms and neural networks is proposed on the publicly available BackBlaze hard disk datasets. The failure prediction experiment is conducted only with S.M.A.R.T., that is, the learned characteristics collected by self-monitoring analysis and reporting technology, which are internally counted during the operation of the hard disk. The experimental results show that this ensemble learning model is able to outperform other independent models in terms of evaluation criterion based on the Matthews correlation coefficient. Additionally, through the experimental results on multiple types of hard disks, an ensemble learning model with high performance on most types of hard disks is found, which solves the problem of the low robustness and generalization of traditional machine learning methods and proves the effectiveness and high universality of this method.

Fabrication of THz corrugated wakefield structure and its high power test

We present overall process for developing terahertz (THz) corrugated structure and its beam-based measurement results. 0.2-THz corrugated structures were fabricated by die stamping method as the first step demonstration towards GW THz radiation source and GV/m THz wakefield accelerator. 150-upmum thick disks were produced from an OFHC (C10100) foil by stamping. Two types of disks were stacked alternately to form 46 mm structure with sim 170 corrugations. Custom assembly was designed to provide diffusion bonding with a high precision alignment of disks. The compliance of the fabricated structure have been verified through beam-based wakefield measurement at Argonne Wakefield Accelerator Facility. Both measured longitudinal and transverse wakefield showed good agreement with simulated wakefields. Measured peak gradients, 9.4 MV/m/nC for a long single bunch and 35.4 MV/m/nC for a four bunch trains, showed good agreement with the simulation.

Trueness and precision of artificial teeth in CAD-CAM milled complete dentures from custom disks with a milled recess

Statement of problemStudies on the movement of artificial teeth during the manufacturing of computer-aided design and computer-aided manufacturing (CAD-CAM) complete dentures using the custom disk method with milled recesses and on whether the movement is within a clinically acceptable range are lacking. PurposeThe purpose of this in vitro study was to assess the trueness and precision of the artificial teeth on custom disks the recesses of which were manufactured using a milling machine and to compare the results with the recesses manufactured using a 3-dimensional (3D) printer. Material and methodsFour types of artificial teeth (maxillary left central incisors [Max-L1], mandibular left central incisors [Man-L1], maxillary left first premolars [Max-L4], and maxillary left first molars [Max-L6]) were prepared. Milling data were created, and 3 of each type of tooth were attached to each disk made up of 3 concentric circles (large, medium, and small). Five each of the 3D-printed custom disks and custom disks with milled recesses were milled based on the milling data. Standard tessellation language data were obtained through cone beam computed tomography and superimposed by using a CAD software program. Mean absolute error (MAE) values were calculated to assess trueness and precision; MAE values of artificial teeth in custom disks with milled recesses and 3D-printed custom disks were statistically compared by using the 2-way analysis of variance test with 2 factors, 2 types of custom disks and 4 types of artificial teeth, and the Tukey post hoc comparison (α=.05). ResultsRegarding position trueness, the MAE value of Man-L1 on the milling custom disk was significantly lower than that of the 3D-printed custom disk (P<.001), whereas the MAE values of Max-L4 and Max-L6 on the milling custom disk were significantly higher than those on the 3D-printed custom disk (P<.001). No significant difference was found in the MAE value of the position trueness of Max-L1 between the milling and 3D-printed custom disks. Regarding position precision, the MAE values of Max-L1, Man-L1, and Max-L4 on the milling custom disk were significantly lower than those on the 3D-printed custom disks (P=.002, P<.001, P=.025, respectively). However, no significant difference was seen in the MAE value of position precision of Max-L6 between the milling and 3D-printed custom disks (P=.180) ConclusionsMovement of artificial teeth during the manufacture of dentures using the custom disk method and custom disks with milled recesses was within a clinically acceptable range.

Biomechanical analysis of single- and double-level cervical disc arthroplasty using finite element modeling.

Recently, many different types of artificial discs have been introduced to persevere the biomechanical behavior of the cervical spine. This study compares the biomechanical behavior of single- and double-level cervical disc arthroplasty, that is "Prestige LP and Mobi-C" on the index and adjacent segment. A three-dimension finite element model of C2-C7 was developed and validated. In single-level prostheses, the Prestige LP or Mobi-C was implanted in the segment C5-C6, while the double-level arthroplasty was integrated at both segments C4-C5 and C5-C6 in the FE model. The intact FE and prosthesis-modified models were constrained from the inferior endplate of the vertebra C7 and applied a compressive load of 73.6 N with a moment load of 1 Nm on the odontoid process of the vertebra C2 to produce flexion/extension, lateral bending, and axial rotation. The prosthesis-modified model's range of motion and intradiscal pressure were determined and compared to the intact model. Also examined the impact of the prostheses on the stress at the bone-implant interface. The range of motion of the implanted segments in both single- and double-levels arthroplasty was increased while that of the adjacent segment of implanted segments decreased. The intradiscal pressure in both levels of arthroplasty was greater than in the intact model. In conclusion, Mobi-C's cervical prostheses could better preserve the normal range of motion and maintain intradiscal pressure than the Prestige LP.

Density of binary disc packings: Playing with stoichiometry

We consider hard-disc mixtures with disc sizes within ratio 2−1, that is, the small disc exactly fits in the hole between four large discs. For each prescribed stoichiometry of large and small discs, the densest packings are rigorously determined via a computer-assisted proof. The density is maximal for the 1:1 stoichiometry: the large discs then form a square grid in each interstitial site of which a small disc nests. When there is an excess of large discs, the densest packings are made of a single phase which mixes the two types of discs in a chaotic way (it can be described by square-triangle tilings). When there is an excess of small discs, on the contrary, a phenomenon of phase separation appears: the large discs are involved in the densest 1:1 stoichiometry phases while the excess of small discs form compact hexagonal phases.

Influence of Aging on the Fracture Characteristics of Polyetheretherketone Dental Crowns: A Preliminary Study.

Although polyetheretherketone (PEEK) is becoming more widely used in dentistry applications, little is known about how aging will affect this material. Therefore, this study aimed to investigate the influence of an aging treatment on fracture characteristics of PEEK dental crowns. Additionally, the impact of the addition of titanium dioxide (TiO2) into PEEK was examined. Two types of commercial PEEK discs were used in this study, including TiO2-free and 20% TiO2-containing PEEK. The PEEK dental crowns were fabricated and aging-treated at 134 °C and 0.2 MPa for 5 h in accordance with the ISO 13356 specification before being cemented on artificial tooth abutments. The fracture loads of all crown samples were measured under compression tests. Results demonstrated that adding TiO2 enhanced the fracture load of PEEK crowns compared to TiO2-free PEEK crowns before the aging treatment. However, the aging treatment decreased the fracture load of TiO2-containing PEEK crowns while increasing the fracture load of TiO2-free PEEK crowns. The fracture morphology of TiO2-containing PEEK crowns revealed finer feather shapes than that of the TiO2-free PEEK crowns. We concluded that adding TiO2 increased the fracture load of PEEK crowns without aging treatment. Still, the aging treatment influenced the fracture load and microscopic fracture morphology of PEEK crowns, depending on the addition of TiO2.

Effects of Different Titanium Surfaces Created by 3D Printing Methods, Particle Sizes, and Acid Etching on Protein Adsorption and Cell Adhesion, Proliferation, and Differentiation.

The surfaces of 3D printed titanium prostheses have major impacts on the clinical performance of the prostheses. To investigate the surface effects of the products generated by 3D printed titanium on osseointegration, six surface types of titanium discs produced by the direct metal laser sintering (DMLS) and electron beam melting (EBM) methods, with two sizes of titanium particles and post-printing acid etching, were used to examine the surface topography and to explore the protein adsorption, pro-inflammatory cytokine gene expressions, and MC3T3-E1 cell adhesion, proliferation, and differentiation. The EBM-printed disc showed a stripy and smooth surface without evidence of the particles used, while the DMLS surface contained many particles. After acid etching, small particles on the DMLS surface were removed, whereas the large particles were left. Moreover, distinct proteins with low molecular weights were attached to the 3D printed titanium discs but not to the pre-printing titanium particles. The small titanium particles stimulated the highest TNF-α and IL-6 gene expressions at 24 h. The alizarin red content and osteocalcin gene expression at day 21 were the highest in the groups of acid-etched discs printed by DMLS with the small particles and by EBM. Therefore, the acid-treated surfaces without particles favor osteogenic differentiation. The surface design of 3D printed titanium prostheses should be based on their clinical applications.

Formation and Morphology of the First Galaxies in the Cosmic Morning

We investigate the formation and morphological evolution of the first galaxies in the cosmic morning (10 ≳ z ≳ 4) using the Horizon Run 5 (HR5) simulation. For galaxies above the stellar mass , we classify them into disk, spheroid, and irregular types according to their asymmetry and stellar-mass morphology. We find that about two-thirds of the galaxies have a Sérsic index <1.5, reflecting the dominance of disk-type morphology in the cosmic morning. The rest are evenly distributed as incidental and transient irregulars or spheroids. These fractions are roughly independent of redshift and stellar mass up to ∼1010 M ⊙. Almost all the first galaxies with at z > 4 form at initial peaks of the matter-density field. Large-scale structures in the universe emerge and grow like cosmic rhizomes as the underlying matter-density fluctuations grow and form associations of galaxies in rare overdense regions and the realm of the galactic world is stretched into relatively lower-density regions along evolving filaments. The cosmic web of galaxies forms at lower redshifts when most rhizomes globally percolate. The primordial angular momentum produced by the induced tidal torques on protogalactic regions is correlated with the internal kinematics of galaxies and tightly aligned with the angular momentum of the total galaxy mass. The large-scale tidal field imprinted in the initial conditions seems responsible for the dominance of disk morphology and for the tendency of galaxies to reacquire a disk postdistortion.

Comparative biomechanical analyses of lower cervical spine post anterior fusion versus intervertebral disc arthroplasty: A geometrically patient-specific poroelastic finite element investigation.

Background/ObjectiveThe optimal surgical technique for the treatment of cervical degenerative disc disease (CDDD) towards decreasing the risk of adjacent segment disease (ASD) remains elusive. This study aimed to comparatively investigate the biomechanics of the lower cervical spine following fusion (ACDF) and artificial disc arthroplasty (Bryan® and Prestige LP®) using a validated geometrically patient-specific poroelastic finite element modeling (FEM) approach.MethodsTen subject-specific pre-operative models were developed and validated based on a FEM approach. Poroelastic models were then constructed using post-operation images for three different treatment scenarios: ACDF; Prestige LP® and Bryan® artificial discs at the C5–C6 level. The biomechanical responses at both surgical and adjacent spinal levels were studied subject to static and cyclic loading.ResultsPostoperatively, greater range of motion (ROM), higher annulus fibrosus stress and strain values, and increased disc height and fluid loss at the adjacent levels were detected post ACDF, as compared with pre-op as well as artificial disc arthroplasty. The facet joint forces were larger for the Prestige LP® disc, particularly during extension. The lowest values in disc height and fluid exchange were observed in the Bryan® artificial disc arthroplasty models.ConclusionBiomechanical analyses revealed that ACDF poses the highest potential risk for adjacent disc degeneration. The artificial discs investigated here (Prestige LP® and Bryan®) not only preserved motion at the instrumented level, but also sustained the pre-op ROM and decreased the intradiscal pressure (IDP) and facet joint forces (FJFs) at adjacent levels, particularly during flexion/extension. The Bryan® artificial disc demonstrated the most efficacy in maintaining the natural poroelastic characteristics of adjacent discs.The translational potential of this articleThis study provided a technique for clinicians to use quantitative data towards subject-specific evaluation to comparatively evaluate the impact of ACDF and disc arthroplasty using two types of artificial discs on the biomechanics of the cervical spine. It confirms differences in the poroelastic characteristics of adjacent discs for different fixation techniques, and reveals the advantage of artificial discs with a flexible core for decreasing the risk of ASD.

Does Protocatechuic Acid Affect the Activity of Commonly Used Antibiotics and Antifungals?

The aim of this study is to evaluate the efficiency of protocatechuic acid (PCA) in enhancing the commonly used drugs used to fight against nosocomial infection. These drugs are represented by routinely used antibiotics, synthetic chemotherapeutic agents with an antimicrobial spectrum, and antifungals. Three concentrations of PCA were added to 12 types of commercial disks used for antibiotic and antifungal susceptibility and tested against bacterial and yeast strains represented by Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. The results proved that PCA increased up to 50% of the antibacterial activity, especially that of levofloxacin against Staphylococcus aureus and Escherichia coli. These formulations will lead to new drug design ideas containing a smaller amount of antibiotics with the same effectiveness.