Large Thread Research Articles

ANALYSIS OF THE FORM AND SURFACE OF DENTAL IMPLANTS

The aim of the work – to study the peculiarities of the shape and surface relief of the main types of dental implants. Materials and methods. 12 dental implants used in the medical practice of Ukrainian dental clinics were studied. The study of the shape and surface relief of the implants was carried out using a scanning electron microscope GSM-649 (Japan). Results. All implants in the apical part have the shape of a cone with threads and cutting grooves. The thread with a large profile is located in the apical part of the implant, has an average pitch of turns of 1.1±0.05 mm and a profile height of 0.3±0.02 mm. The thread with a small profile is located in the part of the implant near the neck, has a pitch of 0.4±0.02 mm and a profile height of 0.1±0.02 mm. The thread pitch of implants with a single profile is 0.8±0.05 mm, and the height of the profile is 0.2±0.01 mm. Threads with a triangular profile have a profile angle of 50.0±2.9 degrees. The highest roughness is the surface of the top of the fine profile thread with the height of micro-uniformities from 7.0±2.2 to 36.0±8.3 μm, the smallest roughness with the height of micro-uniformities from 3.0±1.1 to 14.0±6.1 μm have surface areas in the area of the implant neck. Conclusions. 50% of the examined implants were made with two thread profiles: a large one in the apical side and a small one closer to the neck, 50% – with the same thread profile from the apical end to the neck. In most implants, the thread with a small profile is made in the form of annular grooves. The large thread of the implants had a rectangular, rounded and triangular profile with one or two steps. In some implants, as they approach the neck, the shape changes and the height of the thread profile decreases. The shape of the profile of small threads in all implants was close to rounded. The implants had different surface roughness. The highest roughness was recorded on the surface of the top of the small profile thread, and the lowest – in the area without a thread in the area of the implant neck.

Prediction of the “Screw-nut” gear life

A method has been developed for predicting the service life of a screw pair nut with a large thrust thread, which is based on the energy theory of wear. Based on the results of finite element modeling using the DEFORM-3D software package, the dependence of the change in normal pressures on the contact surface of the nut with the screw along the height of the thread projection was established. Using the SMTs-2 friction machine, a series of experiments was carried out and the coefficient of friction and the energy index of wear intensity were determined for bronze of the brand BrA9Zh3L, used in the manufacture of nuts for screw mechanisms with coarse threads. The calculation of the service life of the nut of the pressure device of the rolling stand of the hot rolling mill 2000 has been performed. The limit value of the number of revolutions of the screw is established, the excess of which leads to critical wear and destruction of the threads.

Design and performance of a 3D-Printed magnetorheological fluid-based adaptive vibration isolator

Emerging additive manufacturing (or 3D printing) can be advantageous for developing magnetorheological fluid (MRF)-based vibration isolators (MRVIs) because their designs can be easily and efficiently customized and also in-situ fabrication and repairing can be possible. In this study, a simple and compact adaptive MRVI was fabricated by using a 3D printing method. A masked stereolithography (MSLA) 3D printer was used for the fabrication of the rubber bellow and plastic lid parts of the MRVI. The electromagnet was mounted onto the lid, the reservoir was filled with an MRF, and the lid was simply assembled with the reservoir using a 3D-printed large thread without traditionally machined components. Using a material testing machine, the damper forces of the 3D-printed MRVI were measured under a constant velocity loading condition for different magnetic fields. From these tests, the magnetic field-controllable performances of the MRVI such as the MR yield force, the dynamic force range, the dissipated energy, and the secant stiffness were obtained. For the evaluation of the long-term performance reliability of the MRVI due to the MRF sedimentation, its magnetic field-controllable performances were tracked for 156 days with the variable testing intervals. Finally, the feasibility of the 3D-printed MRVI was experimentally confirmed.

Epidermal threads reveal the origin of hagfish slime.

When attacked, hagfishes produce a soft, fibrous defensive slime within a fraction of a second by ejecting mucus and threads into seawater. The rapid setup and remarkable expansion of the slime make it a highly effective and unique form of defense. How this biomaterial evolved is unknown, although circumstantial evidence points to the epidermis as the origin of the thread- and mucus-producing cells in the slime glands. Here, we describe large intracellular threads within a putatively homologous cell type from hagfish epidermis. These epidermal threads averaged ~2 mm in length and ~0.5 μm in diameter. The entire hagfish body is covered by a dense layer of epidermal thread cells, with each square millimeter of skin storing a total of ~96 cm threads. Experimentally induced damage to a hagfish's skin caused the release of threads, which together with mucus, formed an adhesive epidermal slime that is more fibrous and less dilute than the defensive slime. Transcriptome analysis further suggests that epidermal threads are ancestral to the slime threads, with duplication and diversification of thread genes occurring in parallel with the evolution of slime glands. Our results support an epidermal origin of hagfish slime, which may have been driven by selection for stronger and more voluminous slime.

Design and Analysis of Intelligent Agricultural Monitoring System Based on Biological Intelligence Optimization Algorithm

The traditional optimization method has insufficient intelligence, slow operation speed, and some problems in the calculation of optimal parameters when facing the relationship between too large sample size and complex thread. The biological intelligence optimization algorithm is based on the genetic and evolutionary mechanism of the genetic system. The smart agricultural system is the application of new IOT technology in the field of smart agriculture, mainly including real-time monitoring, wireless monitoring, and remote image and analysis functions. Through this topic, it is concluded that (1) when the parameter is set to μ = 0.02, β = 0.99, the deviation of the optimal value = 1.74, the deviation of the average value = 3.86, the standard deviation of the experimental value = 3.81, the performance evaluation = 2.68, and the maximum number of peaks = 4. It can give full play to the advantages of various algorithms and learn from each other's strengths. (2) The sNIOA algorithm is the best. Compared with the NIOA algorithm, the accuracy of N is increased by 50% and the accuracy of L = 8 is increased by 20%. Compared with the NGA algorithm, the error of I is reduced by 23.5% and the offset of M is reduced. NPSO algorithm pm performance is improved by 20%, and pmk peak value is reduced by 20%. The domestic research on smart agriculture has experienced explosive growth, and the research has been carried out from the concept of smart agriculture, related technologies, constraints, industrial chain, etc., to provide theoretical guidance for the development of smart agriculture. The worst algorithm parameter is the NIOA model whose offset increases little, the performance decreases by 20%, and the peak value becomes worse. (3) The smart agriculture project uses the latest Internet of Things and cloud computing technology, and based on the analysis of big data and artificial intelligence technology, a new service form is proposed, that is, a cloud, network, and platform composite service system to establish a regional closed-loop ecological chain integrating agricultural production, processing, and marketing. (4) In the biological genetic algorithm model, the recall rate of Cp is low, the ROC curve fluctuates greatly, the specificity AEa is poor, and the sensitivity is not high. Using the integrated technology integrating GIS technology, RS technology, spatial statistics, mathematical models, and other methods, based on the differences of various temporal and spatial scales and their monitoring methods, combined with regression model and spatial sampling method, quantitative analysis was performed, and its influencing factors were analyzed. The comparison shows that the optimal F1 score of biological intelligence optimization parameters is up to 23% higher, the accuracy rate Ao is increased by 20%, and the accuracy rate is high.

Pointer-Based Divergence Analysis for OpenCL 2.0 Programs

A modern GPU is designed with many large thread groups to achieve a high throughput and performance. Within these groups, the threads are grouped into fixed-size SIMD batches in which the same instruction is applied to vectors of data in a lockstep. This GPU architecture is suitable for applications with a high degree of data parallelism, but its performance degrades seriously when divergence occurs. Many optimizations for divergence have been proposed, and they vary with the divergence information about variables and branches. A previous analysis scheme viewed pointers and return values from functions as divergence directly, and only focused on OpenCL 1.x. In this article, we present a novel scheme that reports the divergence information for pointer-intensive OpenCL programs. The approach is based on extended static single assignment (SSA) and adds some special functions and annotations from memory SSA and gated SSA. The proposed scheme first constructs extended SSA, which is then used to build a divergence relation graph that includes all of the possible points-to relationships of the pointers and initialized divergence states. The divergence state of the pointers can be determined by propagating the divergence state of the divergence relation graph. The scheme is further extended for interprocedural cases by considering function-related statements. The proposed scheme was implemented in an LLVM compiler and can be applied to OpenCL programs. We analyzed 10 programs with 24 kernels, with a total analyzed program size of 1,306 instructions in an LLVM intermediate representation, with 885 variables, 108 branches, and 313 pointer-related statements. The total number of divergent pointers detected was 146 for the proposed scheme, 200 for the scheme in which the pointer was always divergent, and 155 for the current LLVM default scheme; the total numbers of divergent variables detected were 458, 519, and 482, respectively, with 31, 34, and 32 divergent branches. These experimental results indicate that the proposed scheme is more precise than both a scheme in which a pointer is always divergent and the current LLVM default scheme.

Adult Women’s Interest in Facial Skincare Using the Thread Lifting Method

This study aims to determine the factors that influence the interest of adult women in facial skincare using the thread lifting method. The population of this study was consumers who visited the clinic to do facial treatment thread lifting. The research sample was taken as many as 34 female consumers aged 30-60 years, who visited the clinic to do facial treatment thread lifting. The research method used was a descriptive quantitative method. Data were collected using a survey method. The survey in this study uses a closed questionnaire to get an overview of the aspects of wants, interests, needs, knowledge. The research instrument used a Likert scale with a range of 1-5 levels. The answers range from very positive (scale 5) to very negative (scale 1). Based on the results of the study showed that the interest of adult women in thread lifting large threads on indicators of need with a percentage of 78.7%. So, it can be concluded that the interest of adult women in thread lifting for facial skin care is in a good category.

Immediate implant placement in molar extraction sites: a 1-year prospective case series pilot study

BackgroundThere is a growing tendency to place single tooth implants immediately after extracting a failing tooth in the posterior region. The aim of this prospective case series pilot study was to evaluate immediate implant placement in molar post-extraction sites during a 1-year follow-up period.Materials and methodsFifteen consecutive patients with a single failing molar in the maxilla or mandible, and presenting enough bone to expect primary implant stability and an implant site free of infection, were included. The implants, with a large thread depth and sharp thread edges, were placed in each patient according to a two-staged surgical procedure. Three months later, a full contour screw-retained zirconia restoration with an angulated screw channel abutment was provided. Clinical and radiographic examinations were performed 1 month and 12 months after placing the restoration. In addition, the patients’ satisfaction with the restoration was scored after 12 months.ResultsFour out of 15 of the mobile implants had to be removed before the 1-year evaluation. The implant and restoration survival rates were 73.3% at the 1-year evaluation (n = 15). The mean marginal bone loss, from loading to the 12-month follow-up, was 0.17 mm (n = 11). The mean plaque, calculus, peri-implant mucosa, bleeding, and pocket probing depth scores were low, depicting healthy peri-implant conditions. The patients were very satisfied.ConclusionIt was demonstrated, within the limitations of this study, that immediate placement of regular diameter implants in molar post-extraction sites in the maxilla and mandible resulted in a high implant failure rate during a 1-year follow-up period.Trial registrationNetherlands Trial Register, NL8117. Registered 24 October 2019 - Retrospectively registered, https://www.trialregister.nl/trial/8117.

Estabilidade primária do implante dental

Primary stability derives mainly from mechanical involvement with the cortical bone and the lack of mobility in the bone bed at the insertion of the implant and depends on the quantity and quality of the bone, the surgical technique, and the design of the implant. The titles were captured in the database PubMed, Scielo, and relevant Brazilian magazines to identify the primary stability, after the insertion of the implant in the region indicated in the protocol. Tapered implants showed greater primary stability compared to cylindrical implants, when placed under bone density conditions. The geometry of the implant is an important factor in the degree of primary stability. Based on this, large threads are desirable in cases of poor bone quality. The insertion torque values are very important for the clinical determination of the levels of primary stability and the absence of micro movements whenever an immediate load is applied. The implant, used as if it were the last cutter, when correctly inserted, penetrates with pressure in the bone store if its diameter is larger than that of the cutter perforation. The implant design plays an influential role in achieving its primary stability.

内螺纹铣削加工精度的试验研究

内螺纹铣削加工精度的试验研究

Rapunzel Syndrome and Small Bowel Intussusceptions Due to a Cotton Thread Bezoar: A Case Report

AbstractRapunzel syndrome is a rare disease in which a trichobezoar extends into the duodenum or distal small intestine. It is associated with compulsive eating of indigestible substances or pica and is more common in cases of underlying psychiatric disturbances. If left untreated, gastrointestinal bezoars with or without the Rapunzel syndrome may lead to several complications such as ulceration, perforation, peritonitis, pancreatitis, biliary obstruction, severe nutritional disturbances, and rarely intestinal obstruction. We present an exceptionally rare case of Rapunzel syndrome caused by a large cotton thread bezoar in an adolescent girl, associated with multiple jejunal intussusceptions. Further, we present a literature review of this entity. An interesting association of bezoar with intussusception is explained. Since a history of pica may not be forthcoming in all cases, it is important to be familiar with the imaging characteristics, complications, and management of bezoars.

Mode of machining of a round thread with a large step

The modification of the realization method for processing internal rope threads [14], using additional equipment, namely a monotooth tool that has the ability of outer cylindrical surface treatment, and the boring system, has allowed to adapt the mentioned above method for making external threads. During adaptation, a machining technology has been developed to allow producing an external rope thread of any size in one passage of the tool. The created technology of machining provided an opportunity for conducting research, as a result of which it was established the possibility of processing the external threaded surface. The study also allows to produce metal joints with an external large pitch rope thread. It should also be noted that the method does not require the use of specific high-cost equipment for cutting external large pitch rope threads.

Supersaturation with water explains the unusual adhesion of aggregate glue in the webs of the moth-specialist spider, Cyrtarachne akirai

Orb webs produced by araneoid spiders depend upon aggregate glue-coated capture threads to retain their prey. Moths are challenging prey for most spiders because their scales detach and contaminate the glue droplets, significantly decreasing adhesion. Cyrtarachne are moth-specialist orb-weaving spiders whose capture threads adhere well to moths. We compare the adhesive properties and chemistry of Cyrtarachne aggregate glue to other orb-weaving spiders to test hypotheses about their structure, chemistry and performance that could explain the strength of Cyrtarachne glue. We show that the unusually large glue droplets on Cyrtarachne capture threads make them approximately 8 times more adhesive on glass substrate than capture threads from typical orb-weaving species, but Cyrtarachne adhesion is similar to that of other species after normalization by glue volume. Glue viscosity reversibly changes over 1000-fold in response to atmospheric humidity, and the adhesive strength of many species of orb spiders is maximized at a viscosity of approximately 105–106 cst where the contributions of spreading and bulk cohesion are optimized. By contrast, viscosity of Cyrtarachne aggregate glue droplets is approximately 1000 times lower at maximum adhesive humidity, likely facilitating rapid spreading across moth scales. Water uptake by glue droplets is controlled, in part, by hygroscopic low molecular weight compounds. NMR showed evidence that Cyrtarachne glue contains a variety of unknown low molecular weight compounds. These compounds may help explain how Cyrtarachne produces such exceptionally large and low viscosity glue droplets, and also why these glue droplets rapidly lose water volume after brief ageing or exposure to even slightly dry (e.g. < 80% RH) conditions, permanently reducing their adhesion. We hypothesize that the combination of large glue droplet size and low viscosity helps Cyrtarachne glue to penetrate the gaps between moth scales.

Prevailing Torque Locking in Threaded Fasteners

This paper presents analyses of prevailing torque locking features common in locknuts, inserts and bolts. Existing manufacturing specifications for these components quantify required minimum and maximum locking torque values for a wide range of thread sizes. The self-loosening moment inherent to threaded fasteners and dependent on joint preload and thread pitch is computed and compared to the specification locking torque values. The self-loosening moment alone, i.e., not including loosening from external loads, is found to exceed the minimum locking torque manufacturing specification values for all fastener sizes at typical preload and for some large thread sizes is found to exceed the maximum locking torque specification. Calculations are provided for SAE and AN fasteners. Sample prevailing torque measurements from locknuts are presented which are well above the minimum specification. Analysis for the loosening moment from an external axial load is developed and presented with example calculations. Fastener locking requirements are defined.

Accelerate multi-thread path-dependent digital image correlation by minimizing thread competition for real-time deformation measurement

With the increasing demands on the real-time measurement using digital image correlation (DIC), the fast and ultra-fast computation are attracting much more attention from academic and engineering fields in last decades. Multi-thread parallelization is a recognized effective method to raise the correlation speed of traditional single-thread DIC up to higher order of magnitude. However, for the path-dependent parallel DIC based on specific initial guess propagation method, competition between different threads greatly cuts down the overall speed, because different threads visit the same queue or status matrix at the same time. Therefore, the desired linear speed-up ratio growth could hardly be achieved especially for large thread number. In this work, three novel strategies are proposed to minimize the thread competition for the existing path-dependent parallel DIC, including i) allocating private queues for private thread, ii) restarting idle thread if others are busy, and iii) collecting more uncorrelated neighboring points for subsequent correlation. In this way, the conflict between threads is obviously decreased and experiment results reveal that the proposed method could upgrade the 2D-DIC speed up to 145,000 points per second using 48 threads, which makes the real-time measurement feasible for region of interest (ROI) with less than 5000 points.

Correlation Between Implant Geometry, Implant Surface, Insertion Torque, and Primary Stability: In Vitro Biomechanical Analysis.

Primary implant stability represents the first step for successful osseointegration. The knowledge of the correlation between host bone density, insertion torque, and implant macrogeometry seems to be fundamental to achieve sufficient primary implant bone fixation in each clinical situation. The purpose of this study was to measure, in vitro, the impact of dental implant macrogeometry and insertion torque values on primary stability in relation to different bone densities, representing both the human mandible and maxilla. One hundred twenty 3.8 ± 11-mm commercial dental implants were used. Forty implants had small threads with a machined neck, 40 implants had small threads with a microthreaded neck, and the last 40 implants had large threads with a reverse neck design. Fresh bovine ribs, representing a medium-dense bone density (D2-D3), and fresh ovine iliac crest, representing a soft bone density (D4), were used. Insertion torque and micromobility under lateral force data were recorded for each implant. In the medium-dense bone type, the reverse neck implant design showed less primary implant stability than the conventional straight implant neck. In soft bone, both implants with the large thread design and microthreaded neck implants showed better implant stability than the implant with a small thread design with a straight machined neck. Implants with large and self-cutting threads showed significantly (P < .05) lower micromobility values than other implants in postextractive sites in low-density bone. Implant geometries and bone density are the main factors involved in the degree of primary implant stability. Large-thread implant designs are highly desirable in cases of poor bone quality. Each implant geometry generates an insertion torque value, which is correlated to the stability of that specific implant in a specific bone quality, but the insertion torque is not an objective value to compare primary stability between different implant types.

Characterisation for differential wear between left and right flank faces in turning large pitch internal thread

In turning large pitch internal thread, there are obvious differences between the wear on the same tool's left and right flank faces, which decrease the tool life and the consistency of machining surface quality of threads. Force equations of tool's left and right cutting edges are used to reveal their differences in mechanical condition. Adopting axial direction cutting method, the flank wear experiment is carried to obtain its characteristics of left and right cutting edges and the time-domain signals of tool vibration. During the formation of differential wear of left and right flank faces, the stress state and the vibration of cutting tool are analysed. Finally, distribution functions of flank wear widths are established to reveal the change characteristics of wear width along the cutting edge and the cutting stroke and quantitatively describe the wear processes and differences of left and right flank faces.

Characterisation for differential wear between left and right flank faces in turning large pitch internal thread

Characterisation for differential wear between left and right flank faces in turning large pitch internal thread

SCALO

Shared memory machines continue to increase in scale by adding more parallelism through additional cores and complex memory hierarchies. Often, executing multiple applications concurrently, dividing among them hardware threads, provides greater efficiency rather than executing a single application with large thread counts. However, contention for shared resources can limit the improvement of concurrent application execution: orchestrating the number of threads used by each application and is essential. In this article, we contribute SCALO, a solution to orchestrate concurrent application execution to increase throughput. SCALO monitors co-executing applications at runtime to evaluate their scalability. Its optimizing thread allocator analyzes these scalability estimates to adapt the parallelism of each program. Unlike previous approaches, SCALO differs by including dynamic contention effects on scalability and by controlling the parallelism during the execution of parallel regions. Thus, it improves throughput when other state-of-the-art approaches fail and outperforms them by up to 40% when they succeed.

Strange Stage Fellows? Arthur Miller and Harold Pinter

Abstract The body of critical literature concerned with direct comparison between the drama of Arthur Miller and Harold Pinter divides into two contradictory threads. The older, larger thread sees the work of Miller and Pinter as stylistic and intellectual antonyms for one another, an argument grounded in Pinter's early identification with Esslin's The Theatre of the Absurd (1961) and Absurdism's rejection of the kind of dramatic realism and linguistic coherence associated with Miller's best-known works. More recently a small number of critics have introduced a counter thread of interpretations, exploring the means by which Miller and Pinter represent in selected plays similar political, historical, or sociological ideas. This essay takes inspiration from this later thread, presenting a comparison of similarities between Death of a Salesman's Willy Loman and The Homecoming's Max. The article specifically addresses Willy and Max's self-conferral of a bogus ancestral patriarchic authority over their respective households—an authority that is entirely at odds with the actual conditions of their lives.