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Relationship between mandibular position and support planting in 7-year-old children: pilot study
Get PDFIntroduction: Postural stability can be maintained in balance by muscle tone [1]. Change in the mandibular position or posture, may have influence in the postural reflex, defined as an involuntary defense movement [2] to correct deviations and keep the body in balance. If the postural change is constant, the muscles will move the mandible to a more comfortable position, with consequent postural change2 and plantar support. The aim of the study was to compare the plantar support in centralized and in lateralization mandibular position in seven years’ children. Main text: This study was approved by research ethics committee (No. 4.346.542). A pilot study was carried out with seven-year-old children of both sexes. Photogrammetry was performed with spherical markers in the region of the right tragus and chin symphysis (Fig. 1) concomitantly with baropodometry following (Fig. 2, 3) the protocol established by Bittar et al. [4]. Analysis of mandibular displacement and plantar support were performed with centralized mandibular position (maximum intercuspation) and with lateral displacement to the right and left. Statistical analysis compared the differences in mandibular displacement to the right and left sides using Student’s t test. Differences in plantar support variables with centralized mandibular position and in right and left lateralization position were established by the Anova one way test and the Bonferroni pos test. Significant statistical difference was reached by 5 %. Results: Twelve seven-year-old children were included, 20.8 (3.25) Kg and 1.18 (0.06) meters. The sample present greater lateral displacement of the mandible to the lefts compared to right side. Mandibular lateralization was confirmed with statistical difference compared to mandibular position centralized. No difference in all plantar support variables was observed between the three positions: centralized and left and right lateralization. Conclusions: No differences were observed for plantar support compared position in mandibular lateralization and centralized position. Mandibular lateralization displacements did not change plantar support
To experimental study of performance evaluation of masonry brick bond in shear and compression in comparison
Get PDFThe construction of a structure is prohibitively expensive due to high material and labour expenses. Still, the production of cement, which is the most widely used binding substance in construction, results in the emission of a large amount of CO2 into the atmosphere. It has only recently been discovered that Pakistan is short of approximately 9 million residential constructions. Thus, there is a great need for cost-effective and energy-efficient masonry construction because of economic and environmental concerns. Rat-trap masonry bond creates a cavity in the wall, which serves as both thermal insulation and a cost-saving measure. Because of the inherent property of rat-trap masonry bond, a cavity is formed in the wall, which not only serves as thermal insulation for the interior but is also cost-effective It has been observed that approximately 26.11 % of the total construction cost, comprising of labor and material, can be curtailed by adopting the rat-trap bonding technique. Rat-trap bond construction is recognized as a greener and more sustainable alternative to conventional brick bonds. A comparative study of the structural behavior of the rat-trap and conventionally used English bond has been conducted. 72 prisms of rat-trap bond and English bond from three sources of bricks were tested under compression load at the ages of 28 and 56 days. The same number of prisms were tested under diagonal tension load at both ages. 18 triplet prisms from all sources of bricks were tested for shear bond strength without lateral load, whereas 5 triplet prisms from every brick source were tested with a set of lateral pre-compression loading of 29 psi, 87 psi, and 145 psi. The results show that the rat-trap bond has much higher compressive and shear strengths than the English bond
Höegh LNG and Altera Infrastructure is scaling up large scale CCS infrastructure
Get PDFIn a joint initiative, called “Stella Maris CCS” Altera Infrastructure and Höegh LNG are working together to provide cost efficient floating Carbon Capture and Storage infrastructure solutions for a global market, not limited to size or geographical location. Valuable infrastructure experience is brought together; with FPSO (Floating Production, Storage and Offloading) and Dynamically Positioned Shuttle Tankers from Altera and FSRU’s (Floating Storage Regasification Unit) from Höegh. We intend to continue to build on our heritage and experience, using our combined skills to contribute to carbon emission reduction around globe. With the “Stella Maris CCS” project, we will essentially be doing what we are doing today, only in reverse. Our solution, initiated in 2019 as the first of its kind, will offer a large-scale floating infrastructure for collection, transport, and injection of CO2 into subsea reservoirs/aquifers. Our infrastructure concept consists of 2-3 Carbon Collection Storage Units (CCSU) to aggregate volumes at different key locations, 3-4 CO2 Shuttle Carriers and one Floating Storage and Injection Unit, the total amount of CO2 injected with these assets can reach up to 10 million tons per year. In order to realize large scale CCS, the unit costs must come down, and the barriers for emitting industries to invest in capture plants must be lowered. With Stella Maris we are addressing these hurdles. The larger ship design enables carrying volumes of CO2 at low pressure and will allow for greater economies of scale in the absence of a pipeline which places less limitations on distance to reservoir and ultimate flow capacity. Having a centralized conditioning of CO2 in a CCSO hub allows more flexibility for on-site capture design from multiple onshore industrial emission sources with shared port access. To defray high logistics cost in e.g. the Baltic region, a hub and spoke transportation approach enables collection in smaller parcels, milk-run gathering and conditioning for large scale transfer for storage in an offshore subsea reservoir on the Norwegian Continental shelf
Vibration characteristics of mistuned multistage bladed disks of the aero-engine compressor
Get PDFIn order to analyze the vibration characteristics of mistuned multistage bladed disks of an aero-engine compressor, a finite element reduction model of mistuned multistage bladed disks is established based on substructure modal synthesis method. The accuracy of the substructure model was verified by comparing calculation accuracy of the substructure model and the integral model. The influence of different modal truncation numbers on the calculation results are discussed. The vibration modes of each stage of the bladed disks are obtained, the forced response is analyzed from the perspective of strain energy. The result shows that modal truncation number, rotation softening effect, and speed have significant effects on the dynamic frequency calculation results of the multistage bladed disks. The typical mode shapes of the first 200 orders of multistage bladed disks are obtained. With the increase of mistuning standard deviation, the strain energy of multistage bladed disk system decreases gradually
Using vibration data to classify conditions in disk stack separators
Get PDFMounting sensors in disk stack separators is often a major challenge due to the operating conditions. However, a process cannot be optimally monitored without sensors. Virtual sensors can be a solution to calculate the sought parameters from measurable values. We measured the vibrations of disk stack separators and applied machine learning (ML) to detect whether the separator contains only water or whether particles are also present. We combined seven ML classification algorithms with three feature engineering strategies and evaluated our model successfully on vibration data of an experimental disk stack separator. Our experimental results demonstrate that random forest in combination with manual feature engineering using domain specific knowledge about suitable features outperforms all other models with an accuracy of 91.27 %
Application of distance field-based algorithm to adjacent spline surfaces for composite structures boundary modeling
Get PDFThe complex boundary modeling required for simulating composite materials was applied to a broad range of problems, including surface overlap and gap. A novel method for the simultaneous fitting of adjacent spline surfaces based on a distance field has been devised. The fitting method for spline surfaces was constructed using offline spline surface, facet simplification, and residual solid reconstruction. The distance field-based approach of simultaneous fitting of neighboring spline surfaces included producing a distance field for a spline surface and then applying that distance field to nearby spline surfaces. There would be junction and separation issues if neighboring spline surfaces were fitted individually. By simultaneously fitting the nearby spline surfaces with the aid of the equivalence surface of the distance field, it was feasible to avoid overlap and gap
Modelling and experimental investigation of the vibratory conveyor operating conditions
Get PDFThe paper’s objective is to study the dynamic parameters and operating conditions of the vibratory conveyor, which is based on the double-mass oscillatory system and equipped with the pull-type (single-cycle) electromagnetic exciter. The scientific novelty consists in substantiating the conveying capacity of various standard sizes of bolts at different operating conditions defined by the input parameters, particularly supplied voltage. In order to describe the conveying tray vibrations, the simplified mathematical model of the conveyor’s double-mass oscillatory system is developed using the Euler-Lagrange equations and is numerically solved in the Mathematica software with the help of the Runge-Kutta methods. The experimental investigations are carried out at the Vibroengineering Laboratory of Lviv Polytechnic National University and are focused on testing the conveying speed of various bolts at different motion conditions: detachable (bouncing, hopping, jumping over the conveying surface) and non-detachable (sliding along the conveying surface). The obtained results show the basic kinematic parameters of the conveying tray motion at different voltages supplied to the actuating electromagnet and the dependencies of the conveying speeds of various bolts at different motion conditions mentioned above. The paper may be useful for designers and researchers while improving and implementing similar vibratory equipment in various industries
Evaluation of segment convergence and settlement of subway shield tunnel in water-rich complex stratum
Get PDFBased on the shield tunnel construction of the left line of Guowei road station-Qingshan lake west station of Nanchang metro line 3, the study focuses on the adverse effects of tunnel segment convergence and settlement deformation of vault and arch bottom on shield construction in the process of shield tunnel construction in water-rich complex stratum. The time-space curves of segment convergence and settlement value on typical monitoring sections are drawn, their variation laws are analyzed, and the deformation values of monitoring data are analyzed and tested. Based on the analysis results, the qualitative and quantitative evaluation of the overall or local deformation state of each monitoring object of tunnel segment is carried out. The results show that the cumulative deformation of each typical monitoring section is lower than the warning value, and the tunnel segment has a systematic offset in the horizontal and vertical directions of the clearance
Planas direct tracks to treat functional crossbites in children: scientific evidence
Get PDFIntroduction: Posterior functional crossbite is a common malocclusion in children, with a prevalence between 7.5-24 %. It has an important impact on facial functions, and may cause asymmetries in craniofacial development. Different interventions have been used to correct this malocclusion but there is a lack of studies with methodological rigor that support these interventions. Planas Direct Tracks (PDT) constitute one of such interventions. They seek to reestablish the functional occlusal balance of children through selective grinding, complementing this adjustment with composites. Objective: To present the level of scientific evidence available on PDT to correct posterior crossbites. Method: A sensitive search was carried out in the main databases: Pubmed, BVS Odontology, Cochrane, SciElo and Google academic. The articles were selected, duplications removed and critical evaluation of the literature performed classifying the studies according to the evidence pyramid. The aim is to point out ways to improve the quality of the studies. Results: 32 studies were included. 30 studies were narrative reviews, case reports or case series and two were controlled trials. All studies had important biases. No randomized controlled trial was found. Conclusion: So far, there are no studies, sufficiently rigorous methodology, on Planas direct tracks to correct functional crossbites
Skull base flexion and its influence on chewing
Get PDFSkull base asymmetries can occur in the intrauterine period, manifesting from birth as craniofacial asymmetries and should be investigated both in the maxilla and mandible and in the craniofacial region, as they are related to the base of the skull. The objective of this study was to explain that treatment using Craniofacial Biodynamics (CFBD) enables symmetrical craniofacial growth, being recommended from three to six years of age, when the processes of skull base remodeling cease. This study was based on exploratory bibliographic research, aiming at a better understanding of the concepts presented in this therapeutic approach, to verify the influence that such concepts exert on treatment through CFBD. It was evidenced in this research that these asymmetries may be corrected, or even minimized through the CFBD, which relates the ontogenetic development of the skull base with orofacial development