Evaluation Of Different Designs Research Articles

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

BackgroundThe aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances.Methods3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance.ResultsIn the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models.ConclusionsIn the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.

Evaluation of different designs for posterior cantilever zirconia inlay-retained fixed dental prostheses in missing tooth replacement: Stage one results with 18-month follow-up assessment

ObjectivesThis clinical study aimed to investigate the outcomes and survival rates of different variations of inlay-retained fixed dental prostheses (IR-FDPs) composed of monolithic zirconia ceramic. The IR-FDPs with a single-retainer design were used for replacing missing mandibular second premolars. The research evaluated the effectiveness and longevity of these prostheses in clinical settings. MethodsA total of 30 IR-FDPs (n = 30) were placed for 27 female patients who presented with missing mandibular second premolar teeth. For this study, the mandibular first molar was chosen as a retainer for the cantilever IR-FDPs and the study involved a random assignment of participants into three distinct groups, each comprising 10 individuals (n = 10). The criterion for the grouping was the retainer design: inlay ring (IR), lingual coverage (LC), and occlusal coverage (OC). The three groups included mesial inlay box with the same dimensions (3 mm height, 3 mm width and 2 mm depth). All IR-FDPs were manufactured using monolithic high translucent 3Y zirconia and the connector area to the cantilever pontic was adjusted to dimensions of 3 × 3 mm for all designs. The restorations were bonded using adhesive resin cement. The clinical and radiographic evaluations of the restorations were conducted for a duration of 18 months, following the modified FDI (World Dental Federation) criteria. ResultsThe restorations were observed in stage one for a period of 18 months. Only one restoration in group LC was debonded after 10 months and re-bonded. The clinical quality of all crowns and the patient's satisfaction were high. No adverse soft tissue reactions around the crowns were observed and only one abutment in group IR was endodontically treated after 12 months. ConclusionsZirconia cantilever IR-FDPs offer a viable short-term treatment option for replacing missing posterior teeth, providing esthetic and functional benefits while minimizing invasiveness. Over an 18-month observation period, these prostheses have demonstrated a remarkable survival rate of 100% and a success rate of 96.6%. These findings suggest the effectiveness and reliability of zirconia cantilever IR-FDPs as a short-term solution for replacing missing posterior teeth. Clinical significanceZirconia cantilever IR-FDPs could present a practical solution for addressing posterior tooth loss, especially in cases where implant placement is not recommended and conventional fixed dental prostheses entail excessive invasiveness.

Performance evaluation of different designs of back-contact perovskite solar cells

Back-contact design for the architecture of devices is a promising approach to develop high-performance perovskite solar cells. Here, numerical simulation methods are used to investigate device properties of back-contact perovskite solar cells (BC–PSCs) with the quasi-interdigitated, flat-interdigitated, and interdigitated electrode designs. The results highlight the principal differences in the designs of the electrodes and provide an investigation and analysis of the impact of these electrodes on the photovoltaic properties of their BC-PSCs. The effect of the perovskite photoactive layer electronic properties on the performance of BC-PSCs is also investigated. It is revealed that while BC-PSCs with the quasi-interdigitated electrode design can potentially produce power conversion efficiencies (PCEs) well above 25 %, BC-PSCs with the flat-interdigitated and interdigitated electrode designs are more tolerant to electronic imperfections in the perovskite layer and can produce PCEs higher than those in devices with the quasi-interdigitated electrode design. Manufacturing and prospective use of electrodes with the quasi-interdigitated, flat-interdigitated, and interdigitated designs in developing BC-PSCs are discussed from the experimental standpoint.

Evaluation of Different Designs of Isolated Cells to Raise Single Rice Seedlings for SRI Mechanized Transplanting

Numerous benefits of the system of rice intensification (SRI) have been documented since SRI was popularized 30 years ago. To date, more than 58 rice growing countries are practicing SRI, covering around 4 million ha of paddy fields and involving more than 10 million farmers. Many paddy farmers shy away from practicing SRI due to extreme labour endurance and number of labors required, especially during transplanting and frequent weeding. The manual transplanting technique to ensure proper root establishment of the seedlings, makes SRI less appealing to many paddy farmers. Furthermore, the transplanting shock is a problem arises from manual transplanting technique needs to be solved that resulted to damaged roots causing delays in crop establishment and reducing productivity. Mechanized transplanting of the young single seedlings into the paddy fields at a wider plantation area eliminates drudgery and enables better exposure to sunlight, water, air, and nutrients. This paper presents a solution to overcome the problem of transplanting shock and the back-breaking manual transplanting, which was achieved by containing the roots of each seedling in a grid of isolated cells. Several designs of the isolated cells to contain the root system were fabricated and tested. These include using aluminum square cells, polyvinyl chloride pipe circular cells, biodegradable grid cells, biodegradable conical capsules, and germinated seeds sowed in a grid without isolated cells. The typical grid cell size was 15 mm by 15 mm with a depth of each cell varied from 40 mm to 60 mm. The most promising design was one with single seedlings raised in bio-degradable capsules arranged close together to fit the conventional rice seedling tray of 300 mm by 600 mm and can accommodate 684 capsules per tray. Upon reaching 2-3 leaf stage, the seedlings with undisturbed roots are ready to be transplanted into the paddy fields using the currently available rice transplante rs.

Fault-tolerant design and evaluation for a railway bogie active steering system

ABSTRACT Active suspension system can drastically improve dynamic behaviours of the railway vehicle but will also introduce safety-critical issues. The fault-tolerant analysis, therefore, is essential for the design and implementation of active suspension. However, this issue did not receive enough attention so far and only few papers can be found related to the fault tolerance of active steering for the railway vehicle. In this work, an approach based on Risk Priority Number is established to present quantitative assessment for fault tolerance of actuation system. Then this method is adopted to compare nine different active steering schemes resulting in a novel, comprehensive approach that enables a quantitative evaluation of different designs of the actuation system and of different principles to improve the fault tolerance. The impacts of typical failure modes are investigated through multi-body simulation and quantified by severity factor. Finally, the fault tolerance of different actuation schemes is evaluated by RPN values.

An assessment of engineered log jam structures in response to a flood event in an upland gravel‐bed river

AbstractEngineered log jams (ELJs) are employed to address river restoration goals and a range of river management problems including coarse sediment movement. In the Bowmont Water, a dynamic wandering gravel‐bed river in the Scottish Borders, 33 previously untested ELJs primarily designed to capture and store coarse sediment, were installed on a trial basis. Using repeated topographical surveys and field observations, the performance of the ELJs in response to a 5–10 year recurrence interval flood that occurred on the 25 September 2012 was evaluated at two reaches with catchment areas of 28 km2 and 57 km2. Three of the structures were damaged due to scour of surrounding material that exposed the pile anchors and all the timbers of one structure were completely displaced downstream. Sixteen structures induced geomorphic responses and only four induced significant deposition (>0.3 m) above that which would occur naturally within the adjacent active gravel bar deposition zones. The placement in gravel bars, minor channel blockage ratio created by the structures and their porous nature limited the hydraulic interference and in turn geomorphic responses. Therefore the ELJ placement goal of increasing sediment storage was not fully met. This study contributes to the empirical evidence base for ELJ performance evaluation of different designs in a range of physiographic settings needed to validate performance and refine design. Using these initial findings and knowledge gained from other studies, recommendations for improving the design and placement strategy are proposed. Copyright © 2016 John Wiley & Sons, Ltd.

Photoelasticity in Dentistry: a literature review

Photoelasticity consists of an experimental technique of stress analysis. This technique is very used in most different areas including Dentistry. This literature review presents the several applications of photoelastic technique in Dentistry the several applications of photoelastic technique in Dentistryas well as its advantages and disadvantages. Literature review:Based on this method of analysis, it is possible the verification of the stress distribution and deformation in structures with complex geometry as maxilla and mandible. It can be used to evaluate the distribution of stress on several types of prosthesis as removable partial denture systems with different retention systems, conventional implant prosthesis, overdentures and Brånemark protocols. Moreover, photoelasticity can be used to assess the stress generated by various by various orthodontic movements, different orthodontic systems and different materials (orthodontic wires). In addition, it is used to analyze different defects of maxillectomy, splint types on traumatized tooth and post-core restoration methods. This technique can also be used to assess dental instruments such as evaluation of different designs of periodontal probe. Conclusion: The photoelastic analysis has been a technique of great importance in health area studies, more specifically in Dentistry. Based on this method of analysis, it is possible to measure the stress distribution and deformation in structures with complex geometry as maxilla and mandible.

Is the capture success of orchid bees (Hymenoptera, Apoidea) influenced by different baited trap designs? A case study from southern Brazil

Orchid bees are increasingly applied on Neotropical biomonitoring and bioindication studies due to the relative easiness of sampling and identification when compared to other bee groups. A considerable number of orchid bee community studies have been adopting baited traps as a sampling method, especially for replication purposes. However, the trap attributes are variable, and hitherto no evaluation of different designs was carried out. Here, five attributes of baited traps were tested: trap volume, number of entrance holes, presence of landing platform, kind of landing platform, and fixation content. We use Mann-Whitney tests to access differences in richness and abundance capture rates for each trap design. We found that volume, number of entrance holes, and fixation content do not influence orchid bees capture. However, the design without landing platforms had a significantly higher capture rate for richness when compared with sanded landing platforms. On the other hand, analyzing the kind of landing platform, we detected a significantly higher richness and abundance for the trap with landing platforms glued with sand. Despite the fact that the effects of different designs tested here were very punctual, we consider that results from samples taken with different baited trap designs are comparable. Some adjustments on trap design can be done according to the particularities of future studies.

Gas-to-Liquid Process Optimization for Different Recycling Configurations and Economic Evaluation

Synthesis gas production by the steam methane reforming process and its subsequent use in Fischer–Tropsch synthesis for gas-to-liquid applications is studied in this work. A base case of synthetic crude oil production is developed and is compared with three different alternative designs. Common tail gas recycling configurations from the Fischer–Tropsch products to the upstream units are investigated with and without carbon dioxide separation prior to the Fischer–Tropsch reactor in the three alternates. A kinetic model proposed for a nickel based catalyst is used for synthesis gas production and a cobalt based model is used for Fischer–Tropsch synthesis in the process simulation. Process optimization was carried out, for economic evaluation of different designs, subject to a well-defined and concise set of constraints. Economics of all four designs are evaluated by the Aspen Process Economic Analyzer for a comprehensive and meaningful comparison.

Biomechanical Evaluation of Different Designs of Glenospheres in the SMR Reverse Shoulder Prosthesis: Micromotion of the Baseplate and Risk of Loosening

BackgroundEarly outcomes of reverse shoulder arthroplasty have been encouraging. Scapular notching remains a major concern. In an attempt to reduce this problem, newer glenospheres are available. This biomechanical study performed in vitro, assessed the micromotions of baseplate in different designs of glenospheres and the relative risk of loosening.MethodsA dynamic shear force was applied to each type of glenosphere in various angles of abduction. The micromotion of the glenoid baseplate after 1000 cycles of dynamic loading was measured and compared.ResultsEccentric glenospheres were shown to have increased micromotion compared to the concentric designs of the same size. The greatest baseplate micromotion (26.83 μm) was well within the accepted limit for osseous in growth into uncemented prosthesis.DiscussionWe therefore conclude that the magnitude of the increased micromotion is small and is not expected to adversely affect osseous in growth onto the glenoid baseplate.

A perching mechanism for micro aerial vehicles

Micro Aerial Vehicles (MAVs) with perching capabilities can be used to efficiently place sensors in aloft locations. A major challenge for perching is to build a lightweight mechanism that can be easily mounted on a MAV, allowing it to perch (attach and detach on command) to walls of different materials. To date, only very few systems have been proposed that aim at enabling MAVs with perching capabilities. Typically, these solutions either require a delicate dynamic flight maneuver in front of the wall or expose the MAV to very high impact forces when colliding head-first with the wall. In this article, we propose a 4.6 g perching mechanism that allows MAVs to perch on walls of natural and man-made materials such as trees and painted concrete facades of buildings. To do this, no control for the MAV is needed other than flying head-first into the wall. The mechanism is designed to translate the impact impulse into a snapping movement that sticks small needles into the surface and uses a small electric motor to detach from the wall and recharge the mechanism for the next perching sequence. Based on this principle, it damps the impact forces that act on the platform to avoid damage of the MAV. We performed 110 sequential perches on a variety of substrates with a success rate of 100%. The main contributions of this article are (i) the evaluation of different designs of perching, (ii) the description and formal modeling of a novel perching mechanism, and (iii) the demonstration and characterization of a functional prototype on a microglider. (See accompanying video and http://lis.epfl.ch/microglider/perching.mpg.)

Biomechanical evaluation of different designs of glenospheres in the SMR reverse total shoulder prosthesis: Range of motion and risk of scapular notching

Reverse total shoulder arthroplasty is a treatment option for cuff tear arthropathy. Scapular notching remains a concern. This biomechanical study compared the range-of-motion in different designs of glenospheres and hence the relative risk of scapular notching. A precision coordinate device was used to investigate four different designs of glenospheres (SMR prosthesis); 36 mm concentric (Standard), 36 mm eccentric, 44 mm concentric, and 44 mm eccentric glenospheres. The centre of rotation in each design was first established. The position of the humeral prosthesis was recorded in the plane of the scapula to compare the degree of adduction and the total range-of-motion. Eccentric glenospheres were found to improve range-of-motion by allowing a higher degree of adduction. Larger diameter glenospheres were found to improve range-of-motion by increasing adduction and abduction. Compared to the 36 mm concentric (standard) glenosphere, the 36 mm eccentric glenosphere improved adduction by 14.5 degrees, the 44 mm concentric glenosphere improved adduction by 11.6 degrees, the 44 mm eccentric glenosphere improved adduction by 17.7 degrees. Eccentric glenospheres with a center-of-rotation placed more inferiorly were shown to improve adduction. This design may reduce the clinical incidence of scapular notching.

Evaluation of different designs of temporary electric fence systems for the protection of maize against wild boar (Sus scrofa L., Mammalia, Suidae)

Among free living animals in Slovenia, wild boar (Sus scrofa) damages agricultural land by rooting and primarily by directly feeding on open fields. In some areas of Slovenia this large wildlife animal causes more than 50% of all estimated damage to cultivated plants grown on arable and forage fields. Many techniques for controlling wild boar and preventing damage are known, but none of them is optimal. In a trial for preventing wild boar ingress into maize fields different designs of electric fence system were used. The trial in which we used an electric fence to prevent wild boar from entering a maize field was erected in the area of Šmihel near Postojna (Slovenia). We decided to erect the electric fence at the end of July, after the fertilization of the maize. The following designs of electric fence systems were used: 1) a plastic post with a polywire and two polytapes with spacings of 15, 15, and 30 cm between them; 2) a plastic post with polywire and a polytape with spacings 25 and 25 cm between them; 3) a steal post as a wire offset in an inverted L shape on which three screws on rod insulators were fixed at a height of 15, 30, and 55 cm from the ground. A polytape at a height of 30 cm acted as depth and it was a so-called three-dimensional design of electric fence. No breaks through fencing were observed until the harvesting time of the maize for silage, although boar tracks on the outside of the fenced field were observed. Damage to arable fields in the vicinity of the protected field was also recorded.

Design and Implementation of Retention/Filtration Media for Sand Control

Summary The factors that control the performance of sand-control screens that use woven metal mesh as the filter media (i.e., commonly called premium screens), are not, generally, well understood by the end user. The end user is told that premium sand-control screens use filter media such as Dutch, Dutch Twill, or a Reverse Dutch Twill woven metal mesh, and in some cases the manufacturer will promote the benefit of multiple layers of woven-metal-mesh filter in the screen to control the sand. All this information is interesting, but the end user really does not understand the significance of the information. This paper presents the results of a study to evaluate the effect of different metal-mesh weaves on the performance (e.g., dirt holding capacity, and plugging tendency) of media commonly used in sand-control screens. The work also introduces a new approach to designing sand-control screens that use woven-metal-mesh material. The performance criteria used in the evaluation of different designs for the filter media include the control of solids and the impact of particle size distribution on the formation of plugging on the surface and in the filtration media. Laboratory testing demonstrates that use of a different type of construction of the retention/filtration media allows for greater performance than media currently used in premium sand-control screens. The significance of the approach discussed in this paper is the ability to design and engineer a premium sand-control screen with a retention/filtration medium for a given particle size distribution of the formation that allows for maximum oil production and minimum solids production. Critical to the success of this approach to designing sand-control screens is the thorough evaluation/testing of multiple media types to create the "formation specific" design.

Comparative characteristics of industrial packings for heat-and mass-exchange processes

An actual problem relative to selection of the optimal type (shape) and size of a packing for tower equipment used in chemical engineering is examined. Appropriate criteria are proposed for comparative evaluation of different designs of packings. Practical examples are cited for solution of this important problem.

Evaluation of different designs of temporary electric fence systems for the protection of maize against wild boar (Sus scrofa L., Mammalia, Suidae)

Among free living animals in Slovenia, wild boar (Sus scrofa) damages agricultural land by rooting and primarily by directly feeding on open fields. In some areas of Slovenia this large wildlife animal causes more than 50% of all estimated damage to cultivated plants grown on arable and forage fields. Many techniques for controlling wild boar and preventing damage are known, but none of them is optimal. In a trial for preventing wild boar ingress into maize fields different designs of electric fence system were used. The trial in which we used an electric fence to prevent wild boar from entering a maize field was erected in the area of Smihel near Postojna (Slovenia). We decided to erect the electric fence at the end of July, after the fertilization of the maize. The following designs of electric fence systems were used: 1) a plastic post with a polywire and two polytapes with spacings of 15, 15, and 30 cm between them; 2) a plastic post with polywire and a polytape with spacings 25 and 25 cm between them; 3) a steal post as a wire offset in an inverted L shape on which three screws on rod insulators were fixed at a height of 15, 30, and 55 cm from the ground. A polytape at a height of 30 cm acted as depth and it was a so-called three-dimensional design of electric fence. No breaks through fencing were observed until the harvesting time of the maize for silage, although boar tracks on the outside of the fenced field were observed. Damage to arable fields in the vicinity of the protected field was also recorded.

Small Vaccination Experiments with Binary Outcome: The Paradox of Increasing Power with Decreasing Sample Size and/or Increasing Imbalance

In animal vaccination experiments with binary outcome (diseased/non diseased), the comparison of the vaccinated and control group is often based on the Fisher exact test. A tool for the evaluation of different designs is proposed, based on the expected power of the Fisher exact test. The expected power can sometimes unexpectedly increase with decreasing sample size and/or increasing imbalance. The reasons for these peculiar results are explained and compared to the results of two other types of tests: the unconditional test and the randomisation test. In a vaccination experiment with a restricted number of animals it is shown to be important to consider expected power in order to choose the most appropriate design.

Control Curve Design for Nonlinear (or Fuzzy) Proportional Actions Using Spline-based Functions

This work explores a novel approach fora systematic design of a nonlinear mapping system typicallyfor nonlinear, or fuzzy, PID control applications. The paper investigates a nonlinear design of proportionalactions using spline-based functions. Specifically, the controller uses Bézier curves to formthe nonlinear mapping in order to emulate fuzzy PID systems. While other researchers have addressed the fuzzy systemsfor approximations of given functions, we believethat, in general control problems, these approximationsshould be considered in dealing with the properties of unknowncontrol actions. Proportional action is selected asa basic function for nonlinear control curve designs. The reasons for this selection are discussed. Specific heuristic properties for the proportional action are defined based on the intuitions in general PID controller applications. The new controller is designed to be compatible with these properties. The nonlinearity variation index is used as a process-independent measure for evaluation of different designs. The system has been shown to improve the conventional fuzzy PID controllers on three aspects. These include a high degree of transparency with respect to nonlinear tuning parameters, versatility to cover various nonlinear functions, and simplicity of nonlinear mapping expressions.

The prediction of distortion in formed orthodontic appliances.

The theoretical prediction of the onset of distortion within a retraction U-loop as derived from a knowledge of the maximum bending moment, the wire characteristics and the loop dimensions was found to be in good agreement with the experimental measurements carried out on large scale models of the U-loops. The ability to predict distortion in appliances should be of use in any comparison of the properties of the different designs of U-loop or in the evaluation of different designs of orthodontic appliance.

A fast low noise silicon detector for electron spectroscopy up to 1 MeV

A 1 mm thick silicon pad detector has been developed for the Atlas Positron Experiment (APEX) [1,2]. This experiment requires efficient detection of positrons and electrons with energies up to 1 MeV with an energy resolution of better than 10 keV and time resolution of less than 2 ns. To satisfy these requirements, the detectors should be 1 mm thick with low leakage current and be capable of operation at voltages greater than needed for full depletion. To enhance the charge collection time, the detectors should also withstand cooling to liquid nitrogen temperature. These requirements have been satisfied using diodes manufactured on high resistivity silicon in combination with a segmented guard ring structure (multiguard) and a process optimized to reduce the bulk generated leakage current. A room temperature leakage current of 1 nA/cm 2 was achieved and an energy resolution of 3.6 keV FWHM was measured with 30 pF input capacitance on a charge sensitive preamplifier. At −130°C with 90 pF input capacitance an energy resolution of 3.4 keV FWHM and a time resolution of 1.2 ns was measured for 500 keV electrons in coincidence with gamma rays detected in a BaF 2 scintillator detector. Results from the evaluation of different designs and process approaches are discussed.