Arch Shape Research Articles

Innovative FRP-Reinforced Self-Bearing Arches

The architectural beauty of curved structures is recognized worldwide. Owing to their balanced form, vaults, domes, and arches were largely adopted over the last centuries. Currently, the erection of new curved masonry structures is dramatically reduced. However, strengthening existing arches is often required to prevent their collapse under static or seismic force. Present limitations regarding such constructions include the antiquated and expensive erection technique employed for curved members. Moreover, the assembly of provisional supporting structures (scaffolding) is generally time- and cost-consuming. Accordingly, the following research provides an innovative construction method that focuses on overcoming the drawbacks of the scaffolding-based approach. A fast lift-up technique was developed to reduce the time and costs of traditional construction techniques. Specifically, the required number of blocks that constitute the arch in this study was aligned side by side on the floor and then connected using a bonded strip of composite material (i.e., FRP—fiber-reinforced polymer). The middle block was then lifted. Thus, each corresponding block could be rotated around the contact point with the adjacent block. When all blocks left the floor, an arch shape was achieved. To validate the proposed method in terms of mechanical performance, an experiment was conducted, as reported herein. A traditional masonry arch built using scaffolding was tested for comparison, and two types of reinforced arches were tested until failure. The first was traditionally built and then reinforced, whereas the second was built using the proposed innovative technique. The specimens were instrumented and tested under a centered or eccentric vertical point load. In all cases, the composite application prevented failure of the hinged joints, as is typical of unreinforced arches, resulting in significantly increased loadbearing capacity, which registered scatters of |11|% and |28|% for the centered and eccentric loads, respectively, when comparing the traditional reinforced arch with the innovative solution.

Application of the dynamic Monte Carlo method to pedestrian evacuation dynamics

In this study, we investigate a two-dimensional lattice model for crowd evacuation dynamics by using a dynamic Monte Carlo (DMC) method. This model is built on the microscopic Arrhenius dynamics along with the exclusion rule in which stochastic processes govern the individual movements depending on the relative distance to the room exit. Even though individual decision-making procedures can be complicated during the evacuation in an emergency, our model can quantitatively estimate the time for them to evacuate and predict the emerging patterns of the crowds during the process. The results exhibit the phenomena such that pedestrians spontaneously gather at the exit and form an arched shape close to the door. The DMC simulations and observations agree with the corresponding study in the literature. The DMC algorithm is computationally efficient due to its major property —“rejection-free”, which makes it a suitable tool to simulate evacuation dynamics for a large group of pedestrians.

Modified Tributary Area and Pressure Arch Theories for Mine Pillar Stress Estimation in Mountainous Areas

This paper describes a parametric study using discrete element modeling (DEM) of partial mining in a mountain terrain with in situ pillars for overburden support. For room and pillar mining or strip pillar mining, the accurate estimation of pillar stress is essential to ensure pillar stability and mine safety. Classical mine design methods such as the tributary area theory (TAT) and the pressure arch theory (PAT) are commonly used to calculate the pillar stress for mines under a relatively flat terrain. However, mine sites with uneven terrains can result in nonuniform stress distributions in the mine system and the classical methods may underestimate the pillar stresses by several times. In this paper, 1200 DEM mine models with terrains that include either a single slope or a valley, have been constructed. Through rigorous numerical modeling, the effects of several design parameters are identified: The influence factors, influence range, and mechanism of the concentrated pillar stresses computed from the models indicate that the shape of an extended pressure arch (EPA) can dictate the accuracy of the TAT and PAT methods. Based on the EPA estimation, a pillar stress estimation method is proposed for the design of mines in mountainous terrains. This paper updated the method of terrain-induced pillar stress concentrations with an improved EPA theory, and the gap between PAT and TAT theories is addressed by further discussion on their relationship and applicability.

Maxillary dimensions and arch shape with palatally displaced canines.

The aim of this study was to explore the effect of palatally displaced canines on maxillary dimensions and arch shape. Occlusal and skeletal landmarks were plotted on cone beam computed tomography (CBCT) images of 156 orthodontic patients: 78 with palatally displaced canines (PDC) (27 left, 28 right, and 23 bilateral) and 78 controls using Mimics™ (Materialise, Belgium). Arch forms were created, and arch width, depth, and skeletal dimensions were measured. T-test (P < 0.05) was used to compare the groups. Geometric Morphometrics (GM) analysis was used to compare the groups and to explore the pattern of covariation between two sets of landmarks. The unilateral PDC group showed an increased first premolar, second premolar, molar widths, and an increased molar depth. No significant difference was found in arch form. The skeletal measurements were generally larger in the PDC group, but the transverse measurements were the most significant. Discriminant Function Analysis (DFA) with cross-validation allowed an accurate classification of 85.9% of the control group and 66.7% of the PDC group. The Mahalanobis distance displayed significant differences among three combinations of groups. Strong covariance was found between the second premolar and all other landmarks. The small sample sizes of the stratified groups precluded recognition of statistical significance. Patients with unilateral PDC displayed significantly wider first, second premolar, and first molar widths, and increased first molar depths. There were no significant differences in arch form; however, GM showed significant differences between the groups and a prominent covariance function for the 2nd premolars.

Economical Polypropylene‐Based Triboelectric Nanogenerator for Self‐Powered Biomechanical Sensor Application

Triboelectric nanogenerators (TENGs) as self‐powered devices are a promising solution for powering sensors of the ever‐expanding Internet of things. However, this potential will be fulfilled only if robust and efficient TENGs are fabricated with economical materials. Herein, a simple and facile approach for fabricating flexible, economical polypropylene‐based TENGs (PP‐TENGs) using readily accessible, inexpensive, and robust material is proposed. The “arch” and “sandwich” shaped structural designs are configured, and their comparative electrical characteristics are studied. The arch shape PP‐TENG is modeled to simulate the potential distribution and the charge transfer mechanism between the frictional layers. The PP‐TENGs are activated by hand tapping, and their electrical characteristics, such as open‐circuit voltage, short‐circuit current, and output power, are studied. To demonstrate their practical utility, PP‐TENG is used to charge capacitors and power light‐emitting diodes. Further, the stored energy of a capacitor is utilized to power an electronic smartwatch and a digital calculator. In addition, the arch‐shaped PP‐TENG is employed as a self‐powered biomechanical sensor, that is, capable of tracking signals induced by different human body motions. Thus, the present work demonstrates the simple fabrication and cost‐effectiveness of PP‐TENG for futuristic applications in battery‐free portable electronics and biomechanical sensors.

Problems and Perspectives on Accelerated Orthodontic Tooth Movement by Low-Level Laser Photobiomodulation

Objective: To determine whether there is any relationship between the thickness of the labial alveolar bone wall in the anterior portion of the maxilla and arch shape.

Orthodontic treatment as a stage of rational dental prosthetics

To improving the effectiveness of complex treatment of adult patients with the absence of individual teeth. Clinical and radiological examination and comprehensive treatment of 37 patients with dental anomalies and the absence of individual teeth were carried out, 24 of them were women (average age 35 years), 13 men (average age 38 years). The patients were divided into two groups: the 1st group - 22 patients with distal occlusion; the 2nd group - 15 patients with mesial occlusion. The results of the developed algorithms for the complex treatment of patients with dental anomalies and the absence of individual teeth during the bite of permanent teeth are presented on a clinical example. The complex treatment included orthodontic treatment using a bracket system, functional fixed telescopic appliance, orthodontic mini screws for bone support and further rational prosthetics. After conducting a clinical and radiological examination and analyzing the data obtained, an individual patient treatment plan was developed, which included orthodontic and orthopedic stages. Orthodontic treatment made it possible to normalize the position of the teeth, the shape of the dental alveolar arches, occlusal planes, improve the bite, which made it possible to prepare the patient for rational prosthetics. The chosen treatment plan was optimal and correct for this patient: all the tasks were solved with changes not only at the dental alveolar level, a stable dental ratio was achieved and not only dental, but also facial parameters were improved. Orthodontic preparation of adult patients before orthopedic treatment significantly improves the quality of orthopedic treatment and allows to achieve the most stable functional and aesthetic results.

Assessment of dental arch forms in a sample of children.

In this study, we investigated dental arch forms in a representative sample of children with mixed dentition. Twenty-four pairs of study models, belonging to twenty-four youngsters (twelve boys and twelve girls aged 8 to 9 years) with acceptable occlusion, were scanned and assessed by Ortho analyzer software. Three transversal and three vertical measurements were acquired to evaluate the lengths and widths of dental arches, and the ratios between these measurements were standardized. Next, the mean standardized parameters were used to define the dental arch form. Unpaired t-tests were used to analyze gender differences for all measures. Subsequently, frequencies and percentages were determined for each arch shape in both jaws and genders, and Pearson's Chi-squared test was used to evaluate differences between genders. Males exhibited higher mean values for all measurements, but without statistical significance. The most prevalent dental arch was the mid form (83.3%) for both jaws and genders.

A comparative study of impression methods using stock tray and intraoral scanner in a completely edentulous patient with an atypical arch shape: a case report

A comparative study of impression methods using stock tray and intraoral scanner in a completely edentulous patient with an atypical arch shape: a case report

Morphometric and Normal 2D CT Anatomic Study of the Vertebral Column of the European Pond Turtle (Emys orbicularis)

Background: European pond turtle is one of the two species of freshwater turtles in Iran. Regarding clinical examinations and diagnostic imaging techniques, it is necessary to have complete anatomical information on this turtle. Objectives: This study provided complete morphometric and normal two-dimensional computerized tomographic scanning information of the vertebrae of European pond turtles. Methods: Ten European pond turtles were used in this study. Computerized tomography (CT) scans were taken from each anesthetized turtle. Then, morphometric parameters were measured in the CT scans of the vertebral column. Results: Atlas was the shortest of the cervical vertebrae, and the eighth cervical vertebra was shorter than the previous vertebrae. The articular surface of the caudal articular processes of the eighth cervical vertebra was bent, and these surfaces were almost vertical. Transverse process width had remained constant in the cervical vertebrae. The transverse process was not observed in the dorsal vertebrae. The first dorsal vertebra had a different shape than others. Conclusion: The particular shape of the last two cervical vertebrae, especially the arched shape of the eight vertebrae. The seventh and eighth cervical vertebrae have the largest transverse distance between caudal articular processes that seem necessary for cervical motion. The limited space of the caudal cervical vertebrae inside the shell chamber can be the reason for the reduction in the length of these vertebrae. The absence of a spinous process in the seventh and eighth cervical vertebrae of the neck may be related to their specific position in the neck retraction.

Foot shape is related to load-induced shape deformations, but neither are good predictors of plantar soft tissue stiffness.

Modern human feet are considered unique among primates in their capacity to transmit propulsive forces and re-use elastic energy. Considered central to both these capabilities are their arched configuration and the plantar aponeurosis (PA). However, recent evidence has shown that their interactions are not as simple as proposed by the theoretical and mechanical models that established their significance. Using three-dimensional foot scans and statistical shape and deformation modelling, we show that the shape of the longitudinal and transverse arches varies widely among the healthy adult population, and that the former is subject to load-induced arch flattening, whereas the latter is not. However, longitudinal arch shape and flattening are only one of the various foot shape-deformation relationships. PA stiffness was also found to vary widely. Yet only a small amount of this variability (approx. 10-18%) was explained by variations in foot shape, deformation and their combination. These findings add to the mounting evidence showing that foot mechanics are complex and cannot be accurately represented by simple models. Especially the interactions between longitudinal arch and PA appear to be far less constrained than originally proposed, most likely due to the many degrees of freedom provided by the structural complexity of our feet.

Correlation of Arch Width and Vertical Facial Morphology in Untreated Adults at a Tertiary Care Centre: A Cross-sectional Study

Introduction: The vertical dimension of a face is crucial in determining facial aesthetics and harmony. It is important for the orthodontist to understand the relationship between dental arch width and facial morphology for correct diagnosis and proper treatment plan. Aim: To determine the relationship between the vertical face pattern, dental arch width and also, to compare arch widths among both untreated female and male adults. Materials and Methods: This quantitative cross-sectional study was conducted in the Department of Orthodontics and Dentofacial Orthopaedics, at Sharad Pawar Dental College, Sawangi, Wardha, Maharashtra, India. The duration of the study was 1 month, from June 2019 to July 2019. Dental casts and lateral cephalograms were collected from 50 untreated adults (25 males and 25 females), aged between 18 to 30 years, who had minimal spacing, crowding and no crossbite. On every patient’s cephalogram, the angle between the plane of the mandible to the cranial base anterior Sella Nasion (SN) angle was calculated. Intercanine, intermolar, and interpremolar widths were measured on dental casts. Females and males arch width were compared. The significance of the differences was assessed using Student’s t-test, one-way Analysis of Variance (ANOVA) test and regression analysis. Results: The mean age of male study participants in the study was 24.44±5.04 years, whereas, mean age of females was 24.88±3.08 years. There were 25 males and 25 females of 18-30 years with mean age of 24 and 25 years, respectively. Arch widths of males were found to be significantly greater than, those of females (p&lt;0.05) and it was observed that, interarch width decreased significantly as the Sella Nasion-Mandibular Plane (SN-MP) angle increased. Regression analyses of male subjects revealed a significant positive relationship between the SN-MP angle. Whereas, the SN-MP angle and width of maxillary first premolar’s buccal cusp tip and the width of the second premolar (most buccal and buccal cusp tip), was found to have a strong correlation in female subjects. Conclusion: It was found that, the width of the dental arch is related to vertical face morphology and gender. During orthodontic therapy, it is recommended to use individualised archwires based on each individual’s pretreatment arch shape and width.

A review study on the design and control of optimised greenhouse environments

Abstract Greenhouses are inflated structures with transparent covering that are used to grow crops under controlled climatic conditions. Crops are protected from extreme climate-related events by being enclosed. Furthermore, the greenhouse design ratio impacts the temperature and humidity distribution profile uniformity as well as the greenhouse. As a result, by effectively designing the greenhouse structure, building materials, dimensions, and shapes, the cost of cooling management strategies can be reduced. Structures with changed arch shapes showed to be more effective at reducing greenhouse cooling demands in hot areas. To demonstrate the tropical region’s inherent capabilities for generating a proper atmosphere for plant development, the optimal temperature, humidity, light, and PH for greenhouse production of crops were supplied. Greenhouse cooling systems are dominated by local environmental characteristics that have an immediate impact on their indoor climatic conditions. Photovoltaic systems in greenhouses have proven technological capacity in real-world settings in this area. This could increase the energy efficiency of some agrivoltaic greenhouse design options.

Influence of presurgical nasoalveolar molding (PNAM) treatment in maxillary dental arch width and nasolabial symmetry in patients with unilateral complete cleft lip and palate.

Unilateral complete cleft lip and palate (UCCLP) is one of the most severe clinical subphenotypes among nonsyndromic cleft lip and/or palate (NSCL/P), that complicates surgical repair operations. Presurgical nasoalveolar molding (PNAM) is a technique used to reshape the nose, lip and alveolar bone of infants with UCCLP before surgery (the modified Mohler rotation advancement cheiloplasty and two flap palatoplasty), with the potential to facilitate surgical repair. However, the effectiveness of PNAM treatment is still a matter of debate. In this paper, the 3Shape scanning system and 3dMD stereophotography were used to assess the short-term and long-term effects of PNAM treatment on the dental arch morphology and nasolabial features of patients with UCCLP, respectively. The findings indicated that PNAM treatment negatively affects both short-term and long-term dental arch shape compared to the treatment without PNAM, particularly in terms of limiting the transverse width of the maxillary canine-to-midline. Regarding the nasal and labial symmetry, PNAM improves the symmetry of the nasal alae in patients over 7 years old and the symmetry of the lip in patients under 7 years old. Moreover, UCCLP patients who received PNAM treatment exhibited a shorter and wider shape of the nostril on the cleft side compared to those without PNAM treatment. In clinical practice, the multidisciplinary team should carefully consider the advantages and disadvantages of the outcomes of PNAM treatment when treating infants with cleft lip and palate.

MRI visualization of aortic recoarctation in the long-term period after surgery (case report)

Case study. Aortic coarctation refers to well-known and well-studied congenital malformations of the cardiovascular system. The success of cardiovascular surgery significantly increased the survival rate of patients, but, unfortunately, did not reduce the risks of serious cardiovascular complications in the long-term postoperative period. One of the significant complications remains recoarctation – repeated narrowing in the area of surgery, which can initiate other complications.The purpose of the study: to present the features of blood flow in the aorta in a patient with aortic coarctation in the long-term postoperative period on the clinical example of a complex MR examination.Material and methods. A 12-year-old patient, at the age of 6, she underwent balloon angioplasty of aortic coarctation. Echocardiographic data revealed a residual gradient at the isthmus of the aorta and expansion of the descending aorta. To clarify the diagnosis, MRI angiography of the heart was performed with intravenous contrast and the use of a cardiopackage for 4D flow analysis (4D flow).Results and discussion. According to the MRI study, a narrowing of the distal aortic arch with aortic dilation after the departure of the left subclavian artery was revealed, which is confirmed by the obtained absolute values of blood flow indicators. MR-angiography of the aortic arch made it possible to visually determine the “gothic” shape of the aortic arch and present 3D reconstructions. 4D flow maps showed acceleration of blood flow to the systole in the area of aortic narrowing, additional vortex flow below the area of aortic narrowing and spiral flow in the descending aorta, which persisted throughout the diastole.One explanation for the abnormal spiral flow in the descending thoracic aorta may be the presence of a “gothic” aortic arch. Also, residual hypoplasia of the aortic arch and narrowing of the isthmus are the leading parameters affecting the pathophysiology of changes in blood pressure during exercise.Conclusion. The 4D-flow MR package in vivo makes it possible to study the flow geometry and blood flow parameters in detail, to obtain a detailed picture of the aortic condition, which gives potential advantages in a comprehensive examination of patients with aortic coarctation under dynamic observation.

The Relationship between Unilateral Palatal Maxillary Canine Impaction and the Morphology of the Maxilla: A CBCT Study in Eastern Province of Saudi Arabia.

This study aimed to examine the correlation between the morphology of the maxilla and unilateral palatally impacted maxillary canine (PIMC) among the Saudi population in the Eastern Province of Saudi Arabia. In this retrospective study, 36 patients' records [(17 PIMC, 8 male, 9 female, mean age 16.75 ± 2.12 years) (19 control; 9 male,10 female, mean age: 17.16 ± 2.12 years)] were included from a teaching dental hospital. On cone-beam computed tomographic images, measurements of maxillary arch length (MAL), palatal vault depth (PVD), intermolar width, sum of widths of 4 maxillary incisors, available arch space (AAS), palatal maxillary width (PMW) in the molar and premolar regions, nasal cavity width (NCW), maxillary arch shape (MAS) (arch length/intermolar width x 100), and palatal vault shape (PVS) (the PVD/intermolar width x100) were performed. Data were analyzed by SPSS-20.0. p-value less than or equal to 0.05 reflected statistical significance. This study's findings depicted that AAS (p = 0.012), PVD (p = 0.028), and PMW in the molar and premolar regions at the level of the alveolar crest (p = 0.002 and p = 0.034) and mid-root (p = 0.004 and p = 0.022) were significantly higher in the control compared to the PIMC group. PVS showed a significant difference between the PIMC and control groups (p = 0.037). However, regarding MAS, no significant difference was observed (p = 0.707). MAS was narrower in PIMC compared to the control group. The control group had a deeper palatal vault and greater AAS compared to the PIMC group. However, no significant difference was observed between groups regarding tooth size or NCW.

Martian buildings: structural forms using in-place sources

On Mars, structural loads and the low tensile strength of in-place Martian binders make existing solutions for Martian structures uneconomical because they are based on the terrestrial sources like inflatable units. Here we address this issue by introducing and analyzing three innovative structural forms in accordance with the structural engineering point of view using symmetric optimum parabolic rotated arch shapes and in-place waterless sulfur-based concrete. These forms minimize the tensile stresses under Martian structural loads. Probable Martian structural loads, including gravity, wind, marsquakes, asteroid and meteoroid impact loads and their effects have been investigated and calculated. The proposed models were analyzed under Martian structural loads using the implicit finite element method and the results were compared to two concrete structural forms from previous studies. The proposed models could tolerate Martian structural loads with complete elastic behavior and would significantly decrease the Martian colonization cost due to using Martian resources and reduce element importing from Earth.

Earthquake Response of Arch Dams including Hydrodynamic effect using ABAQUS

A simple arch dam [1] is analyzed to find responses due to an earthquake, including the hydrodynamic effect of the reservoir water. The simple arch shape dam was modeled as a monolith structure, assuming the linear behavior of dam concrete. The arch dam is modeled with finite elements. The hydrodynamic effect is considered as an added mass of water adhered to the dam’s upstream surface [2]. Natural frequencies and mode shapes are computed for the dam without water and the dam with water. Time history analysis of the dam is performed for the Kern County earthquake (1952), Taft component 111 acceleration time history. The added mass of water is calculated according to the Kuo 1982 [2] research paper. Various results containing Cantilever stresses, arch stresses, and deflections are shown and plotted. Analyses are performed with the help of the Abaqus Software.

Numerical Modeling of Controlling a Floor Heave of Coal Mine Roadways with a Method of Reinforcing in Wet Soft Rock

A floor heave is usually a serious failure phenomenon in mine roadways, especially in the conditions of a wet soft rock. There are bright prospects for using a method of reinforcing for controlling a floor heave in mine roadways under a dramatic heave. In the current research, a floor heave mechanism in the wet soft rock of mine roadways was investigated while the moisture content of the rocks was increasing. That was done by performing numerical simulations in a finite element analysis software system Ansys and by reinforcing the floor in the shape of inverted arch. It was found that a decrease in the modulus of elasticity of rocks caused by saturation leads to a nonlinear increase in a floor heave. This can be explained by the fact that rocks of the floor become plastic strains. A stable correlation was established between water content and a floor heave of a wet rock. It was found that when the floor is reinforced, the proportion of plastic strains in the soil is significantly reduced. The growth of the modulus of elasticity of rocks in the reinforced zone, caused by reinforcing of the floor in the form of inverted arch, leads to a nonlinear decrease of a floor heave. The effective range of floor reinforcing was established. A reliable relation was established between the ratio of the modulus of elasticity of rocks of the reinforced zone to the modulus of elasticity of the surrounding rock and heaving of reinforced rocks. The obtained results can be used to predict the magnitude of heaving of rocks at their saturation, as well as after they are reinforced.

Muscular Systems and Their Influence on Foot Arches and Toes Alignment-Towards the Proper Diagnosis and Treatment of Hallux Valgus.

(1) Background: Static foot deformities, including hallux valgus, are common deformities. The subject under consideration is the role of extrinsic and intrinsic muscles working within muscular systems that shape the arches of the foot and the alignment of the toes. (2) Methods: Based on a literature review, the muscle systems were analyzed. The systems under consideration were as follows: "tendon stirrup" (system I); muscles complementary to the tendon stirrup (system II); "foot lever" (system III); muscles complementary to system III (system IV); "reins of hallux" (system V), a muscular system having distal inserts on the hallux. The shape of the foot arches was analyzed in this context. (3) Results: The correct arch architecture of the foot stabilized mainly by the extrinsic muscle systems determining the function of the intrinsic muscle systems of the foot is described. The proper function of muscular systems shaping the arches of the foot is a prerequisite for the proper function of muscles directly responsible for the alignment of the big toe (hallux) and other foot toes. (4) Conclusion: The action of muscles should be considered in groups (systems) because the action of the group of muscles results in the creation of a new quality of movement. The analysis of individual muscle-pulling forces, especially the moments of force in the weight-bearing foot, may lead to extremely incorrect conclusions. In pathological cases, the restoration of the correct arches of the foot guarantees the recovery of the correct function of the pulling forces of the foot muscles responsible for the physiological alignment of the hallux. This is especially important concerning conservative and surgical treatment of hallux valgus.