Slot Size Research Articles

Assessment of the Hardness of Various Orthodontic Wires

ABSTRACT Introduction: The mechanical characteristics of orthodontic wires are crucial since they have a significant impact on the effectiveness of orthodontic therapy, and patients undergoing orthodontic treatment are becoming more and more picky about their aesthetic preferences. Objectives: The goal of the current investigation was to assess the hardness of various orthodontic wires. Materials and Methods: Three types of wires were employed in this study: nickel titanium (NiTi, USA), beta-titanium (TMA, USA), and stainless steel (SS, Germany). For the upper left canine in this investigation, we utilized an edgewise bracket with a slot size of 0.018″. Epoxy resin was used to implant the wires. The orientation of the brackets was horizontal. Next, a measurement was taken of the brackets’ external surfaces’ hardness. Using an optical microscope, the micrographs of the typical Vickers indentations were captured. The acquired data was assessed statistically. Results: The specimens belonging to the stainless steel, nickel-titanium, and beta-titanium groups had mean microhardness values of 523.24, 367.22, and 321.36, respectively. There were noteworthy outcomes when comparing the three research groups. Conclusion: Among the stainless steel group specimens, the highest microhardness was observed. However, more research is advised.

Influence of Distributor Structure on Through-Sea Valve Vibration Characteristics and Improvement Design

To address the issue of excessive transient noise during the opening and closing of a sea valve, a method for reducing pressure fluctuations during the opening of the electromagnetic hydraulic distributor has been proposed by analyzing the structure and working principle of the distributor. Based on theoretical calculation and simulation analysis, the size and shape of the buffer slot of the flow hole are determined under the condition that the stable working flow rate remains unchanged. An improved electromagnetic hydraulic distributor is developed and tested. The results indicate that this method can effectively control the opening and closing transient noise of the sea valve.

Study on the Influence of Different Slot Sizes on the Flow Field of Transonic Compressor Rotors

Blade slotting technology is an effective measure to improve the flow structure on the suction surface of a blade and enhance the performance of turbomachinery. To investigate the impact of various slot sizes on the flow field of a single-stage transonic compressor rotor, seven kinds of slot schemes were designed and calculated by numerical simulations. The results show that the above slotting schemes significantly enhance the stability margin of the compressor. In particular, the slotting scheme H9W3 increases the surge margin by 60.9% and slightly reduces peak efficiency by 0.3%, with an almost identical maximum pressure ratio. Slotting promotes high-energy fluid to generate jets from the slot located at the exit of the suction side, effectively controlling blade surface flow separation and reducing channel blockage. Square slots are more effective than elongated slots for controlling separation when using differently shaped slots with equal areas. Increasing slot area gradually decreases outlet total pressure at a constant aspect ratio. A slight increase in the overall blade load causes a backward shift in the front portion load.

Characteristic analysis of the vortex excited using the photoacoustic transducer with a spiral light absorption surface

Abstract It is proved that the vortex acoustic field can be excited with laser by designing the photoacoustic transducer with a spiral light absorption surface. The generated acoustic field has a spiral phase wavefront, and the pressure on the central axis along its propagation direction is zero. The orbital angular momentum that can be used for positioning and manipulation of particles is formed by the vortex. The characteristics of the generated acoustic vortex at different frequency and detection position are analyzed for 1-5 topological charge. And the influence of the geometric configurations such as the width and size of logarithmic spiral slot are also studied for the achieving the desired vortex field with focused intensity.

Optimization of solenoid valve design for enhanced electromagnetic force in Variable valve timing systems

This paper investigates the impact of structural modifications in solenoid valves on the electromagnetic force characteristics crucial for efficient Variable Valve Timing (VVT) system operation. Utilizing finite element analysis, various hole and slot configurations within solenoid valve components were examined to determine their effect on the electromagnetic forces generated during valve operation. The study focused on base and spool structural parameters, such as the diameter and number of oil drain holes, the size and position of steel ball slots, and variations in structural dimensions. Results from empirical and simulation data reveal significant findings: larger diameters and an increased number of holes tend to reduce electromagnetic forces, while specific configurations can stabilize or enhance these forces. These findings offer critical insights for optimizing solenoid valve designs in VVT systems with the aim of improving performance and reliability. The study establishes a robust theoretical foundation for further empirical research on the multifactorial effects of valve structure on solenoid performance, paving the way for more refined VVT system designs in the automotive industry.

Energy Efficient Heuristics to Schedule Task Graphs on Heterogeneous Voltage-Frequency Islands

For energy and cost-efficient computing, many desktops and embedded computing devices these days use voltage frequency islands (VFIs) based processors. An island in VFIs consists of multiple homogeneous cores; however, multiple islands are generally heterogeneous in nature. In contrary to architectures (non-VFI) with per-core dynamic voltage frequency scaling (DVFS), in VFI, all the cores in an island run on the same voltage/frequency at the same time. The energy-aware scheduling of task graphs on VFI architectures is challenging and different from non-VFI architectures in which task-based DVFS is possible. However, in VFI scheduling, the time slot for which an island runs on a particular voltage will be decided. In this paper, we analyse 20 different scheduling heuristics for VFI architectures by varying the size of this time slot based on the workload properties and also by varying the voltage/frequency of the time slots. We also propose a heuristic OptSlotVFI to utilize all the slots optimally. The results show that the VFI scheduling heuristics are able to generate schedules which improve energy consumption up to 25% with an equivalent or shorter schedule length than the state-of-the-art approaches.

A Multi-Aperture Technique for Longitudinal Miniaturization of UWB 3 dB Dual-Layer SIW Coupler.

Microwave couplers are used in large numbers in beamforming networks, and their miniaturization can lead to a significant size reduction in the overall phased array. While the miniaturization of 3 dB couplers in the transverse direction (width) has been given considerable attention in the literature, there is minimal to no information on reducing coupler length. This is because of the trade-off between aperture length, bandwidth and coupling strength. The Bethe-Hole theory requires adding multiple apertures in the longitudinal direction for wide bandwidth, thus increasing the device length. Another factor is the aperture size, which determines the coupling strength and puts additional strain on the compactness of a 3 dB coupler. Contrariwise, this paper proposes to merge two weak (and hence compact) coupling mechanisms to design a wideband 3 dB coupler. This is achieved by using a longitudinal rectangular slot and three cross-slots in the transverse direction. Because of weak coupling, the slot sizes are smaller than a conventional 3 dB coupler, hence yielding a device whose length is less than one guided wavelength (λg) without compromising the bandwidth. The presented coupler is 0.63 λg in length, which is smaller than the state-of-the-art while maintaining a fractional bandwidth of 37% that is comparable to half-mode substrate integrated waveguide (HMSIW) couplers.

Broadband multiresonance metasurface antenna based on characteristic mode analysis

ABSTRACT A multiresonance metasurface antenna for C-band application is proposed in this paper. A broadband metasurface with consistent radiation performance is designed using characteristic mode analysis (CMA). The metasurface is formed by 4 × 4 square patches, and circular slots of different radius are etched on the center and edge patches. To achieve consistent radiation, the size of circular slots on the corner patches is increased. The metasurface is excited by slot antenna, and multiple adjacent resonant frequencies are generated by combining two modes of the metasurface and resonant mode of slot antenna. The measured results show that the −10 dB impedance bandwidth of the antenna is 4.22–8.38 GHz (66%), and the peak gain is 8.2 dBi.

Insulation performance improvement for drywall using highly insulated steel studs with slots

Drywall systems are a highly constructible technology with short construction times that allow the recycling and reuse of materials. However, steel studs used to anchor the insulation can cause thermal bridging owing to their high thermal conductivity, which can reduce the insulation performance and thermal comfort of occupants. This study proposes a new design method for drywall systems that can overcome the shortcomings and contribute to building energy conservation. Studs with slots applied in the web area are proposed, and the thermal performance and optimal slot size were determined by thermal analysis simulations. Through sensitivity and regression analysis, a design method for drywall was proposed. The developed studs showed an increase in insulation performance of approximately 22.1 % compared with conventional studs. The error rate between the simulation results and the regression model was 0.4 %. An experiment was conducted to verify the insulation performance of the studs. The results of this study can contribute to expanding the application of drywall technology in the building field by solving the problem of thermal bridging and providing a unique perspective on the drywall.

Queen Triggerfish Balistes vetula Age-Based Population Demographics and Reproductive Biology for Waters of the North Caribbean

Queen triggerfish Balistes vetula is an important reef-associated species for commercial fisheries in the U.S. Caribbean. It exhibits a relatively unique reproductive strategy as a nesting benthic spawner, investing substantial energy in territorial defense, building and maintaining nests, and caring for fertilized eggs during the reproductive season. Prior to this study, no comprehensive life history information existed in the literature for queen triggerfish. This study provides the first comprehensive documentation of age, growth, size/age at sexual maturity, reproductive seasonality, and reproductive output for a Balistes species in the Caribbean. From 2013 to 2023, we collected 2190 fish samples from fisheries-dependent and -independent sources from the waters of Puerto Rico and the U.S. Virgin Islands. Fish ranged from 67 to 477 mm fork length (FL). We documented that queen triggerfish is sexually dimorphic with males attaining larger mean sizes-at-age compared to females and the species is characterized by a moderately young age at median sexual maturity (A50 = 3.3 y). The maximum age for our U.S. Caribbean samples was 23 y based on increment counts from otoliths. Spawning season encompassed the months of December to August in the region, and female spawning frequency ranged from an estimated 2 to 84 times per year; female spawning frequency increased with increasing size and age of fish. We documented that commercial fishers in the U.S. Caribbean mainly target “plate-size” individuals, defined in our study as 235–405 mm FL, which appears to act as a self-imposed slot size range limit and results in the fishery not removing individuals in the smallest and largest size groups at high rates. The percentage of immature fish from fisheries-dependent sources was close to 0 (0.8%). Commercial fishing for queen triggerfish in the region currently appears to be sustainable, but monitoring of the population should continue.

Design and heat transfer numerical analysis of high-speed continuous casting mold water slot system

The water slot structure can reduce the temperature of the mold and increase the heat transfer between the mold and cooling water. It has significant impacts on high-speed continuous casting. Therefore, a three-dimensional model of heat transfer from mold to cooling water was used to analyze the influence of water slot size on the cooling capacity of a single water slot. Then, the fluid flow, heat transfer, and solidification three-dimensional models were used to analyze the temperature distribution and cooling effect of three kinds of water slot molds and non-water slot molds. Finally, the water slot mold was designed to achieve high-speed continuous casting. The results show that to make full use of the cooling water in the water slot, the width and height of a single water slot should be less than 8 mm. Compared with the conventional mold without the water slot structure, the temperature of the mold with the water slot structure significantly decreases. The final design of the mold water slot system is as follows: the water slot width and depth are 8 mm, and the number of water slots on one side of the mold is 9. The water slots have a symmetrical distribution, and the symmetrical plane is the middle plane of the mold. The high-speed continuous casting experiment was carried out, and the casting speed can reach 4–4.5 m/min. The water slot mold in this study can be applied in the high-speed continuous casting process.

Assessment of orthodontic brackets slot size accuracy in different commercially available brackets: An in vitro study

Assessment of orthodontic brackets slot size accuracy in different commercially available brackets: An in vitro study

DIFFERENCE IN FRICTIONAL RESISTANCE BETWEEN LIGATURE WIRE AND ELASTIC MODULE” (AN IN VITRO STUDY)

Introduction: The purpose of this in-vitro study was to compare the frictional resistance forces generated by slid low friction elastomeric ligatures and stainless steel ligatures wire during leveling and alignment phase. Methods: The testing metal plates consisted of three stainless steel 0.022-in slot size preadjusted brackets of lateral incisor, canine and first premolar. First comparison were the bracket position vertically adhered to the plates. The second one were the canine bracket was adhered as a high canine in 2 mm. The forces generated by wires (0.014-in superelastic nickel-titanium) with the 2 types of ligatures at different bracket position were recorded. Results and Conclusions: The results of the present study revealed that there was a statistically significant difference in the frictional force between group A and group B with a p-value of 0.047 which is less than 0.05 level of significance, while there was no statistically significant difference in the frictional force between group C and group D with a p-value of 0.56 which is greater than 0.05 level of significance.

Displacement and stress distribution pattern during complete mandibular arch distalization using buccal shelf bone screws - A three-dimensional finite element study.

To evaluate and compare the distribution of stress and displacement of teeth during mandibular arch distalization using buccal shelf screws. Three three-dimensional finite element models of mandibular arch were constructed with third molars extracted. Models 1, 2, and 3 were constructed on the basis of the lever arm heights of 0 mm, 3 mm, and 6 mm, respectively, between the lateral incisor and canine. A buccal shelf screw was placed at the area in the second molar region with the initial point of insertion being inter-dental between the first and second molars and 2 mm below the mucogingival junction. MBT pre-adjusted brackets (slot size 0.022 × 0.028") were placed over the clinical crown's center with a 0.019 × 0.025" stainless-steel archwire on three models. A retraction force of 300 g was applied with buccal shelf screws and a lever arm bilaterally using nickel-titanium closed coil springs. The displacement of each tooth was calculated on X, Y, and Z axes, and the von Mises stress distribution was visualized using color-coded scales using ANSYS 12.1 software. The maximum von Mises stress in the cortical and cancellous bones was observed in model 1. The maximum von Mises stress in the buccal shelf screw and the cortical bone decreased as the height of the lever arm increased. Applying orthodontic forces at the level of 6 mm lever arm height resulted in greater biomechanical bodily movement in distalization of the mandibular molars compared to when the orthodontic forces were applied at the level of 0 mm lever arm height. Displacement of the entire arch may be dictated by a direct relationship between the center of resistance of the whole arch and the line of action generated between the buccal shelf screw and force application points at the archwire, which makes the total arch movement highly predictable.

A segmented periodic slot array leaky‐wave antenna for beamforming applications

AbstractA segmented periodic slot array leaky‐wave antenna (LWA) is proposed for beamforming applications. The LWA consists of segments, each with a unique propagation constant achieved through varying periodicity and slot size. By using segments with different propagation constants, the proposed LWA can achieve beamforming such as flat‐top beams and side‐lobe level (SLL) reduction. The LWA is based on a substrate‐integrated waveguide with periodic double transverse slots in the broad wall of the waveguide. The double slots allow for reflection‐canceling to suppress the broadside stopband and hence can achieve beamforming capabilities in the backward, broadside, and forward directions. Full‐wave simulations are used to demonstrate the proposed concept for flat‐top beamforming in the mm‐wave band at 30 GHz. Experimental demonstration is conducted using two prototypes for flat‐top beams and SLL reduction, with good agreement with full‐wave simulations.

LoRaSync: Energy efficient synchronization for scalable LoRaWAN

AbstractLow‐power wide‐area networks connect a large number of battery‐powered wireless devices over long distances. Among them, long range wide area networks (LoRaWAN) implement a pure ALOHA medium access scheme to save device energy by minimizing the radio usage. However, frame collisions restrain the network scalability when the traffic load increases. In this context, synchronization can be used to exploit the available bandwidth more efficiently by controlling the timing of frame transmissions and reducing the collision probability. Such strategy allows to increase the network throughput at the cost of an extra energy demand due to the inherent overhead. In that, the entailed network scenario is still supposed to address low power applications. Therefore this article timely presents LoRaSync, an energy‐efficient synchronization scheme designed for LoRa networks of any size. An accurate clock drift model was established based on measurements made on real cheap devices, and leveraged to support the design of LoRaSync. Our mechanism has been used to evaluate the same ALOHA‐based random access but on a time‐slotted basis, thus increasing the maximum achievable throughput compared to the legacy access. Throughput and energy efficiency models are established to evaluate the performances of a LoRaSync‐operated network. These models are validated with a simulation environment mimicking large‐scale deployments, and then used to determine the most energy efficient slot size for any traffic load. As a final proof of concept, LoRaSync has been implemented and tested on a LoRa testbed to demonstrate the feasibility of our solution on real hardware.

Completion Design to Prevent the Production of Sand in a Well by Using Suitable Equipment

The aim of this paper is to propose a completion design to prevent the production of sand in a well named "X" (for confidential reasons) by using suitable equipment. To reach this goal, the equipment materials (metals and elastomers) must be selected. The downhole gravel pack equipment must be chosen, the well schematic drawn and the installation procedure written. The data used are the well-completion design. The well schematics are drawn by using Power Draw 2019. The results show that the recommended metallurgy is stainless steel with 13 chrome. For this case, the best equipment is the wire-wrapped screen with its slot size ranging from 0.008 to 0.012 inch, and the wash pipe size is 1.66 inch. The gravel pack packer, closing sleeve, gravel pack extension, flapper valve, safety shear joint, blank pipe, screen, snap latch and hydrogenated nitrile butadiene rubber material are selected to meet the scope of work. The total cost of the lower completion operation is 354,200$.

Increasing mercury bioaccumulation and biomagnification rates of Nile perch (Lates niloticus L.) in Winam Gulf, Lake Victoria, Kenya

The Nile perch (Lates niloticus L.) commercial fishery for Lake Victoria in East Africa is an important source of revenue and employment. We focused on shifts in food web structure and total mercury (THg) bioaccumulation and biomagnification in Nile perch, and lower food web items collected from Winam Gulf (Kenya) sampled 24 years apart (1998 and 2022). Stable isotope carbon (δ13C) values were higher in all species from 2022 compared to 1998. Stable nitrogen isotope (δ15N) values in baseline organisms were lower in 2022 compared to 1998. In Nile perch, δ15N values were correlated with total length, but the δ15N-length regressions were steeper in 1998 compared to 2022 except for one large (158 cm) Nile perch from 1998 with an uncharacteristically low δ15N value. Total Hg concentrations were lower in lower trophic species from 2022 compared to 1998. However, the THg bioaccumulation rate (as a function of fish length) in Nile perch was greater in 2022 compared to 1998 resulting in 24.2 % to 42.4 % higher wet weight dorsal THg concentrations in 2022 Nile perch for market slot size (50 to 85 cm) fish. The contrasting observations of increased THg bioaccumulation with size in 2022 against decreases in the rate of trophic increase with size and lower THg concentrations of lower food web items imply reduced fish growth and potential bioenergetic stressors on Winam Gulf Nile perch. All samples except 1 large Nile perch (139 cm total length collected in 2022) had THg concentrations below the European Union trade limit (500 ng/g wet weight). However, for more vulnerable individuals (women, children and frequent fish eaters), we recommend a decrease in maximum monthly meal consumption for 55–75 cm Nile perch from 16 meals per month calculated for 1998 to a limit of 8 meals per month calculated for 2022.

Incisor torque expression characteristics in two passive self-ligating brackets placed at different heights. A finite element investigation

ObjectiveThis study investigated torque expression in maxillary incisors using two passive self-ligating bracket types (Damon Q and Pitts 21) placed at different heights using the Finite element method. Materials and methodsTwo passive self-ligating brackets, Damon Q (Ormco, USA) and Pitts 21 (OC Orthodontics, USA) were 3D modeled using micro-computed tomography. Damon Q (0.022ˮ x 0.028″ slot size) and Pitts 21 (0.021ˮ x 0.021″ slot size) brackets were placed on a maxillary central incisor at predetermined vertical heights. Arch wires of size 0.019ˮ x 0.025″ stainless steel (Damon Q) and 0.020ˮ x 0.020” Titanium Molybdenum (Pitts 21) were placed in the bracket slots. ResultsPitts 21 brackets showed higher torquing moments at all bonding heights as compared to Damon Q brackets. The minimum torquing moment was 9.03Nmm at 5 mm for Damon Q and the maximum torquing moment was 14.92Nmm for Pitts 21 at a bracket bonding height of 8 mm. Total deformation for Pitts 21 at a height of 5 mm from the incisal edge was 0.61 × 10−6mm as compared to that of Damon Q which was 0.41 × 10−6mm. Lowest Von Mises stress values were at 27.07 MPa in Damon Q brackets at a bracket height of 5 mm from the incisal edge. Highest Von Mises stress values were 36.80 MPa for Pitts 21 brackets at a bracket height of 8 mm from the incisal edge. ConclusionPitts 21 brackets exhibited superior torquing characteristics compared to Damon Q. Total deformation in Pitts 21 was higher than Damon Q at all tested bracket bonding heights.

Highly-isolated compact self-diplexing antenna

This article introduces a novel low-profile self-duplexing antenna with high isolation for out-band operation applications. The antenna design features two patches, one rectangular and one triangular, both utilizing the quarter-mode substrate integrated waveguide (QMSIW) cavity for enhanced performance. Furthermore, miniaturization is achieved through the incorporation of capacitive slots. The resulting self-duplexing antenna is engineered for operation at both 5.8 and 9.8 GHz frequencies, with an impressive alignment between measured and simulated results. Notably, the antenna’s dimensions are remarkably compact, occupying only 0.08 λg2, while still delivering a remarkable 40 dB isolation between its two ports. Furthermore, the antenna maintains consistent radiation patterns at both frequencies. Simulated gains at 5.8 and 9.8 GHz are 4.1 and 4.6 dBi, respectively, enhancing its suitability for dual-band wireless communications. An additional advantage of this design is its independent tuning of frequency bands, facilitated by adjusting the size of the capacitive slots. The article also delves into the investigation of the tuning circuit model for the self-diplexing antenna, which is crucial in the design process. This model elaborates on how the antenna operates and how the frequency bands can be regulated, providing valuable insights into its functionality and versatility. Moreover, the proposed antenna stands out as the most compact self-duplexing antenna with the highest level of isolation when compared to existing literature, making it a valuable asset for dual-band wireless communication applications.