Ridge Height Research Articles

A three-in-one alveolar process reconstruction protocol for maxillary molar sites with severe residual bone height deficiency: A proof-of-concept pilot study.

Implant placement in maxillary molar sites with severe height deficiency often requires multiple surgeries, which was time-consuming, invasive, and subject to serious postoperative complications. To introduce and assess a three-in-one technique (extraction, alveolar ridge preservation [ARP], and sinus elevation) for augmenting deficiency maxillary molar alveolar ridges. Fourteen patients with severe posterior maxillary ridge height deficiency underwent extraction, sinus elevation via an intrasocket window and ARP using sticky bone and then covered with acellular dermal matrix (ADM). Primary closure was intentionally not obtained. Cone-beam computed tomography and periapical radiography were used to measure dimensional ridge changes over time. Bone biopsies were taken at implant placement 7-21 months after surgery, which proceeded without additional grafting. Peri-implant soft tissue was assessed after 8-12 months of functional loading. Maxillary molar sites (13 first molars, 1 second molar) with a mean sinus floor height of 1.73 ± 0.86 mm and mean buccal plate thickness of 1.62 ± 1.15 mm were elevated and grafted. Immediately after surgery, the mean sinus floor height was 14.03 ± 1.97 mm and the alveolar thickness at virtual implant platform level was 12.99 ± 1.88 mm. After 5-9 months healing, those measurements decreased by 2.45 ± 1.73 mm (p= 0.000) and 3.88 ± 3.95 mm (p= 0.006), respectively. Healed ridges were composed of 18.74% ± 4.34% mean vital bone and 19.08% ± 9.10% mean residual graft. After 8-12 months of functional loading, the peri-implant tissue appeared healthy, and there was a mean marginal bone loss of 0.12 ± 0.11 mm. For maxillary first molar sites with severe sinus floor height deficiency, this minimally invasive three-in-one treatment allows for uncomplicated implant placement and short-term functional stability.

Did the coronavirus disease 2019 pandemic affect orthodontic treatment outcomes? A clinical evaluation using the objective grading system and Peer Assessment Rating index

IntroductionThis study aimed to compare the treatment outcome of patients whose orthodontic treatment was completed before or during the coronavirus disease 2019 pandemic.MethodsPretreatment and posttreatment models of 100 patients treated with fixed orthodontic appliances were evaluated using the peer assessment rating (PAR) index. Posttreatment models and panoramic radiographs were measured and scored with the objective grading system (OGS). All patients had their treatment plans before the coronavirus disease 2019 pandemic, but the orthodontic treatment finishing date was before (prepandemic: group 1, n = 50) or during (pandemic: group 2, n = 50) the pandemic. Intergroup comparisons were tested with an independent samples t test or Mann-Whitney U test. Chi-square test statistics and Fisher exact test were used to compare categorical variables.ResultsSignificant higher posttreatment weighted maxillary alignment score was found in group 2. However, no significant difference was found between the groups concerning the mean total weighted PAR reduction (29.8 ± 9.9 vs 25.6 ± 8.7) and posttreatment total weighted PAR scores (1 vs 2). The PAR index score improvement (%) was similar between the groups (93.7 ± 7.1 vs 89.9 ± 13.0). No statistically significant difference was found between the groups for the total OGS score (32 vs 33). A lower score for marginal ridge height (4 vs 3) and a higher score for buccolingual inclination (7 vs 11), and a lower score for occlusal relationship (3 vs 1) were found in group 2. Canceled appointments (1.1 ± 0.7 vs 4.8 ± 1.6) and the number of missed appointments (0.6 ± 0.5 vs 1.1 ± 0.8) were statistically higher in group 2, whereas the total number of appointments (27.3 ± 8.8 vs 21.8 ± 5.4) were statistically less. The treatment duration was comparable in both groups.ConclusionsReduced and irregular appointments during the pandemic resulted in significantly higher posttreatment weighted maxillary alignment and worsening of the buccolingual inclination. However, the PAR score improvement, total OGS score, and treatment duration were not affected.

Major clinical findings of short implants and virtual surgery: a systematic review

Introduction: After the confirmation and publication of the phenomenon known as osseointegration by Brånemark, dental implants have been used to repair total and partial edentulous jaws. However, the implants were long and had to be longer than 11 mm to be considered functional. Short implants compared to long ones require less remaining bone, reducing the patient's exposure to surgeries for bone grafting, the elevation of the maxillary sinus mucosa, and repositioning of the inferior alveolar nerve. Added to this, several dental treatments have benefited from this digital advance. Objective: To review the literature on short implants installed in both dental arches, evaluating their advantages, disadvantages, indications, and contraindications in the context of virtual surgery. Methods: The present study followed a systematic review model (PRISMA). The search strategy was performed in the PubMed, Scielo, Cochrane Library, Web of Science and Scopus, and Google Scholar databases. Results: A total of 110 articles were found, 64 articles were evaluated and 35 were rejected for not meeting the GRADE classification, and only 29 articles were used in this study to compose the textual part. Based on these findings, it was found that in remote years, authors reported that regions with reduced bone height are favored with the use of short implants not only because of their dimensions but also because of their surface treatment, which suggests that it is an important factor for achieving 100% success rates. The advantages of short implants are related to the simplicity of the technique, installation of implants in remaining bone, avoidance of bone grafts that present questionable results in the increases in height of the posterior alveolar ridge of the mandible, reduction of treatment time, and reduction of costs for the patient. A systematic review and meta-analysis studies analyzed the accuracy of implant placement using computer-guided surgery. A randomized study compared the precision of guided planning of new computer-assisted implant placement techniques, based on models that use CAD/CAM. Conclusion: It was concluded that short implants are a reliable, safe, and practical alternative to be used in any necessary location or situation. They do not show bone loss or resorption over the years, nor are they at risk of fracture or any damage to patients. They are safe to use, as long as they have an adequate design, therefore, fundamental tools in the dental clinic.

Skeletal and dentoalveolar dimensions in unilateral impacted canines: a cone beam computed tomography study.

To compare skeletal and dentoalveolar measurements of subjects with unilateral impacted canine versus the non-impacted contralateral side using cone beam computed tomography (CBCT). 30 CBCTs with unilaterally impacted maxillary canines (Buccal=15, Palatal=15) were selected. Skeletal and dentoalveolar variables (alveolar ridge height of incisors, dentoalveolar height, angulations of incisors and canines, basal lateral width and premolar width) were compared between the impacted and the contralateral sides. Independent t-test was used to compare the variables. There was a significant difference in the mean basal lateral width between the impacted (28.25±1.83 mm) and non-impacted (31.64±2.18 mm) sides. Premolar width was significantly lower on the impacted side (p<0.05). The canines exhibited significantly greater angulations on the impacted side compared to the nonimpacted side. The basal lateral width was significantly higher in the buccal subgroup (29.03±1.65mm) compared to palatal (27.48±1.70mm) on the impacted side. The intra-operator reliability was found to be high (0.99%). Significant differences were seen in canine angulation, premolar width and basal lateral width between impacted vs. non impacted sides. Basal lateral width was higher in buccal impacted cases compared to palatal.

Procedural Roof Generation From a Single Satellite Image

AbstractUrban procedural modeling has benefited from recent advances in deep learning and computer graphics. However, few, if any, approaches have automatically produced procedural building roof models from a single overhead satellite image. Large‐scale roof modeling is important for a variety of applications in urban content creation and in urban planning (e.g., solar panel planning, heating/cooling/rainfall modeling). While the allure of modeling only from satellite images is clear, unfortunately structures obtained from the satellite images are often in low‐resolution, noisy and heavily occluded, thus getting a clean and complete view of urban structures is difficult. In this paper, we present a framework that exploits the inherent structure present in man‐made buildings and roofs by explicitly identifying the compact space of potential building shapes and roof structures. Then, we utilize this relatively compact space with a two‐component solution combining procedural modeling and deep learning. Specifically, we use a building decomposition component to separate the building into roof parts and predict regularized building footprints in a procedural format, and use a roof ridge detection component to refine the individual roof parts by estimating the procedural roof ridge parameters. Our qualitative and quantitative assessments over multiple satellite datasets show that our method outperforms various state‐of‐the‐art methods.

Effects of conventional complete dentures and implant-supported overdentures on alveolar ridge height and mandibular bone structure: 2-year and 6-year follow-up study.

The aim of this study was to compare the changes in mandibular bone structure in edentulous patients who were rehabilitated with conventional complete dentures (CCD) and implant supported overdentures (ISO), by evaluating alveolar bone loss (ABL), panoramic mandibular index (PMI), mandibular cortical width (MCW), gonion index (GI), antegonial index (AI), and articular eminence inclination (AEI). Panoramic radiographs of 63 edentulous patients using CCD, 63 edentulous patients using ISO, and 126 patients without tooth loss were evaluated. Edentulous patients had a 2-year and 6-year follow-up panoramic radiograph image. ABL (anterior, premolar, and molar regions), MCW, PMI, AI, GI, and AEI were measured in each patient. Variation between measurements was analyzed using repeated measures ANOVA test and post hoc Tukey test. Both edentulous groups showed significantly lower mean than without tooth lost group in all measures (p < 0.000). ISO group showed significantly lower mean ABL than CCD group in anterior (p = 0.000), right premolar (p = 0.005), left premolar (p = 0.005), right molar (p < 0.000), and left premolar (p < 0.000) regions in short term. ISO group showed significantly lower mean ABL than CCD group in anterior (p = 0.021), right molar (p < 0.000), and left premolar (p < 0.000) regions in long-term. There is no statistically significant difference between the CCD and ISO groups in right premolar (p = 0.200) and left premolar (p = 0.134) regions in long term. Both edentulous groups showed significantly lower mean MCW (p < 0.000), PMI (p < 0.000), AI (p < 0.000), GI (p < 0.012), and AEI (p < 0.002) than the without tooth loss group. There is no statistically significant difference between the CCD and ISO groups in terms of changes in the mean MCW, PMI, AI, GI, and AEI measurement in short and long term (p > 0.000). In the short and long term, edentulism reduced alveolar crest height, MCW, and AEI in individuals, but had no effect on PMI, AI, or GI. The use of prosthesis did not prevent the decrease of alveolar crest height, MCW, or AEI (CCP or ISO). In the short and long term, however, ISO created less ABL in the mandibular anterior and molar regions than CCD. ABL cannot be halted in edentulous people, but by using ISO instead of CCD for rehabilitation, resorption can be reduced.

Horizontal ridge augmentation by ridge split technique using piezosurgery- exploring the techniques beyond prosthetic replacements for resorbed ridges

Extraction of teeth leads to hasty ridge resorption. Alveolar ridge resorption occurs rapidly in horizontal direction than in vertical direction, thusdemanding ridge augmentation for implant placement.Conventional techniques such as block grafting shows increased post-operative morbidity and requires second surgical site. Horizontal ridge augmentation (HRA) by ridge split technique (RST) is a minimally invasive procedure that aids in ridge expansion, at the same time preventing the need for second surgical site. The case presented here had adequate ridge height but reduced ridge width in mandibular right quadrant. RST was accomplished using piezosurgery in combination with bioactive glass and platelet-rich fibrin (PRF), followed by implant placement. The patient was evaluated periodically at ten days, three months and six months before implant placement.RST provides promising results in terms of gain in ridge width. The use of piezosurgery, bone graft, PRF had added advantage in preservation of the alveolar ridge and post-operative healing. Key words:Ridge augmentation, Ridge split technique, Piezosurgery, Bioactive glass, Platelet-rich fibrin.

Assessment of stress distribution pattern in mandibular buccal shelf area during retraction with different angulation using buccal shelf screws — A 3d finite element study

Orthodontics in its century of existence have had a lot of landmarks in its evolution, but very few can match the clinical impact made by micro-implants and the recently introduced infra-zygomatic crest &amp; buccal shelf orthodontic bone screws. Micro-implants and extra-radicular BS have brought about a renaissance to the field of orthodontics with its concept of absolute anchorage in the past decade. It is an added armamentarium in the hands of an experienced clinician to overcome new clinical challenges and convert even borderline surgical cases to nonsurgical without, compromising with the results achieved. Aim It is a FEM study in which buccal shelf screws are inserted in buccal bone lateral to the distal root of the 2nd molar and 4 mm buccal to the CEJ with different retraction forces and various angulation to study stress pattern in MBS area. Material and Method CBCT 3D image of the study mandible is made and the image transfer to the software. A FEM is created using a dedicated software. Orthodontic buccal shelf screws which is made of titanium alloy (diameter, 2 mm; length, 12 mm; thread ridge height, 0.2 mm; thread pitch, 0.6 mm). Miniscrew implant insertion is designated at 30°, 40°, 60°, 70°, and 90° angulations, and at each angulation a horizontal load of 150, 200, and 250 g is applied. Results BSS when inserted in buccal bone 60-70 degree angulation showed the least stress pattern in mandibular buccal shelf area and 40 – 50 degree angulation showed maximal stress distribution pattern.

Quantitative detection of locomotive wheel polygonization under non-stationary conditions by adaptive chirp mode decomposition

Wheel polygonal wear is a common and severe defect, which seriously threatens the running safety and reliability of a railway vehicle especially a locomotive. Due to non-stationary running conditions (e.g., traction and braking) of the locomotive, the passing frequencies of a polygonal wheel will exhibit time-varying behaviors, which makes it too difficult to effectively detect the wheel defect. Moreover, most existing methods only achieve qualitative fault diagnosis and they cannot accurately identify defect levels. To address these issues, this paper reports a novel quantitative method for fault detection of wheel polygonization under non-stationary conditions based on a recently proposed adaptive chirp mode decomposition (ACMD) approach. Firstly, a coarse-to-fine method based on the time–frequency ridge detection and ACMD is developed to accurately estimate a time-varying gear meshing frequency and thus obtain a wheel rotating frequency from a vibration acceleration signal of a motor. After the rotating frequency is obtained, signal resampling and order analysis techniques are applied to an acceleration signal of an axle box to identify harmonic orders related to polygonal wear. Finally, the ACMD is combined with an inertial algorithm to estimate polygonal wear amplitudes. Not only a dynamics simulation but a field test was carried out to show that the proposed method can effectively detect both harmonic orders and their amplitudes of the wheel polygonization under non-stationary conditions.

The Results of Studying Agronomic Indicators of the Demetra Selection Seeder

Introduction. The technological operation of seed sowing is a main in the seed selecting and growing process. The correct execution is the most important agrotechnical requirement for seeding machinery for selecting and primary seed breeding. The purpose of the study is to determine the main agronomic indicators of the Demetra selection seeder. Materials and Methods. In the study, the methods of a full-scale experiment in laboratory and field conditions were used. The main agro technical indicators of the technological process of sowing seeds by a seeder were determined. Results. As a result of the study, there were determined the main agronomic indicators of the seeder such as its minimum and maximum productivity and the effective seeding rate, departure from the specified seeding rate, irregularity of seed sowing through the seed tubes, instability of total seed sowing, seed crushing, seed sowing depth at optimum coulter penetration depth, quantity of seeds embedded at the specified depth, ridge height after the aggregate passed, and number of sprouts and relative field germination rate. Discussion and Conclusion. It has been found that the Demetra seeder with high accuracy provides qualitative performance of sowing specified number of seeds with both the minimum (1.95 m) and maximum (32.92 m) length of the plot. The departure of the actual seeding from the specified seeding is 0.02‒0.54% for different crops. Unevenness of seeding is 0.22‒1.53% for different crops. At the same time, the instability of total seeding varied in the range of 0.1‒1.1% for different crops. The height of ridges after the seeder passed is 2.6‒3.0 cm. There were no seeds not embedded in the soil by the working bodies of the seeder. Relative field germination of cultivated crops is 82.3‒96.9%.

Comparison of Gonial Angle and Alveolar Bone Height Changes in Panoramic and Lateral Cephalometry Radiography in Growing Patients

Background: This study aimed to compare the gonial angle and alveolar bone height changes between panoramic and lateral cephalometry radiographic images in class II malocclusion patients before and after orthodontic treatment. Methods: The obtained radiographic images were selected from among 120 class 2 malocclusion cases. The gonial angle and alveolar bone height were measured in the midline and molar regions of panoramic and lateral cephalometric radiographs using the software tools before and after the treatment of patients. Study data were analyzed by SPSS statistical software (version 21.0), and a significance level was set to 0.05 for all statistical tests. Results: Based on the results, no significant difference was found regarding the gonial angle before and after treatment on the right and left sides in panoramic radiography and the gonial angle changes before and after treatment in cephalometric radiography (P&gt;0.05). However, the obtained results for posterior and anterior alveolar ridge height were significant in panoramic and cephalometric radiographs (P&lt;0.05). Moreover, the comparison of the measured gonial angle values before treatment in panoramic and cephalometric radiography represented a significant level (P&lt;0.05). Eventually, the statistical results suggested that the alveolar bone height differences between panoramic and cephalometry radiography were significantly different in both anterior and posterior regions after treatment (P&lt;0.05). Conclusions: The findings indicated that only measurements obtained from the panoramic radiography were valid for the gonial angle. However, panoramic and cephalometry radiography procedures cannot be replaced for assessing the anterior and posterior alveolar bone height.

Fine Texture Detection Based on a Solid-Liquid Composite Flexible Tactile Sensor Array.

Surface texture information plays an important role in the cognition and manipulation of an object. Vision and touch are the two main methods for extracting an object’s surface texture information. However, vision is often limited since the viewing angle is uncertain during manipulation. In this article, we propose a fine surface texture detection method based on a stochastic resonance algorithm through a novel solid–liquid composite flexible tactile sensor array. A thin flexible layer and solid–liquid composite conduction structure on the sensor effectively reduce the attenuation of the contact force and enhance the sensitivity of the sensor. A series of ridge texture samples with different heights (0.9, 4, 10 μm), different widths (0.3, 0.5, 0.7, 1 mm), but the same spatial period (2 mm) of ridges were used in the experiment. The experimental results prove that the stochastic resonance algorithm can significantly improve the signal characteristic of the output signal of the sensor. The sensor has the capability to detect fine ridge texture information. The mean relative error of the estimation for the spatial period was 1.085%, and the ridge width and ridge height, respectively, have a monotonic mapping relationship with the corresponding model output parameters. The sensing capability to sense a fine texture of tactile senor surpasses the limit of human fingers.

Direct Sinus Augmentation Procedure for Rehabilitation of Severely Atrophic Posterior Maxilla with Sticky Bone – A Case Report

Aim: Rehabilitation of atrophic maxilla using sticky bone and simultaneous implant placement.&#x0D; Presentation of Cases: Sinus augmentation along with simultaneous implant placement prevents the additional surgery. This often benefits both the patient and the dentist. This case report highlights the sinus augmentation procedure for rehabilitation of a severely atrophic posterior maxilla using Sticky bone, a combination of Xenograft and Platelet rich fibrin with simultaneous dental implant placement.&#x0D; Discussion: Pneumatization of posterior maxilla often complicates dental implant surgery. Various sinus lift surgical procedures have been developed over the years, to increase residual alveolar ridge height. Implant placement is made easier by enhancing the posterior maxilla by various sinus augmentation procedure&#x0D; Conclusion: Direct sinus augmentation procedure using sticky bone for rehabilitation of severely atrophic posterior maxilla with simultaneous implant placement provides a reliable and predictable outcome.

Avaliação das cristas oclusais de dentes pré-molares antes e após o tratamento dental em equinos

ABSTRACT Occlusal ridges of equines appeared in the evolutionary process of the species to increase its capacity of grazing and trituration. The difference in hardness of dental tissues (cementum, dentin, and enamel) and masticatory pressure on the occlusal surface of the hypsodont tooth promote the appearance of sharp occlusal ridges. The aim of this study was to measure and compare the height of the occlusal ridges (HOR) of the fourth premolar (Triadan 408) before and after odontoplasty. Ten Mangalarga Marchador mares aged 5 to 12 years, under extensive management, were evaluated by measuring the HOR in Triadan 408, using plaster models before, immediately after (D0), 15 days (D15) and 50 days (D50) after odontoplasty. Immediately after the procedure the HOR was only 21.9% of the HOR before the occlusal equilibration; however, in 15 days after odontoplasty, 65.9% of HOR was already reestablished and 80.3% after 50 days of the procedure. HOR in the buccal side resurfaced before the lingual HOR, suggesting a higher masticatory pressure of these buccal points. Results of the present study indicate that 15 days after the dental treatment, equines already have food trituration capacity, since HOR is apparent on the occlusal surface of the premolars that underwent odontoplasty.

Solid-State LiDAR 기반 밭 농업용 자율주행 로봇의 두둑 감지를 통한 실시간 주행 경로 생성 알고리즘

Autonomous robots driving in agricultural environments need to create accurate routes to prevent damaging farmland. Herein, a real-time path planning algorithm based on ridge detection using the Livox Mid70 LiDAR is proposed. The field has a steep slope between the furrow and the ridge, and we find data corresponding to this slope from the lidar data. Using two Mid70 LiDARs, we collect the left and right slope data and linearly fit the slope data using the RANSAC algorithm. Finally, the driving route is obtained from the average of the two straight lines. To verify the algorithm, the steering angle needed to follow the driving path was calculated, and an autonomous driving test was conducted in the actual field environment: it was observed that the robot drove stably. Additional tests will be conducted in more rugged terrain.

Impacto de la tomografía computarizada de haz cónico en el diagnóstico y plan de tratamiento preimplantologico de senos maxilares

Objective: To determine the impact of CBCT on diagnostic evaluation and treatment plan for the maxillary sinus in dental implant planning. Material and Methods: Diagnostic evaluation and treatment plan for the maxillary sinus were evaluated by eight specialists experienced in dental implant placement. Eight panoramic radiographs (PAN) and CBCT examinations were obtained from five adult patients with a specific clinical need for dental implants. Evaluation was performed first on PAN then, at least 2 weeks later, on CBCT. Residual alveolar ridge height, mucosal thickening, radiographic findings and treatment plan were recorded. The confidence level was evaluated for both diagnostic evaluation and treatment plan. The kappa statistic for intra-observer reproducibility and McNemar test were performed. Results: In the diagnostic evaluation, CBCT showed significant impact on the diagnosis of radiographic findings. Availability of CBCT significantly changed the treatment plan, for less invasive treatment, or no treatment need. Observers had significantly greater confidence when using CBCT than PAN, when indicating presence of mucosal thickening and radiographic findings in the maxillary sinus. In addition, CBCT increased confidence in the treatment plan. Conclusion: The present study suggests that CBCT has an impact on the diagnostic evaluation of radiographic findings in the maxillary sinus and on the decision to place implants, owing to misdiagnosis of pathology and planning of more invasive treatments when using PAN. Availability of CBCT also improves clinician confidence. Further studies at higher levels of diagnostic efficacy should be performed, to justify the use of CBCT, by evaluating the actual treatment performed and its outcome.

Long-term preservation of ridge dimension following tooth extraction and ridge preservation: A randomized controlled trial of healing at 4- and 12-month healing time points.

To date, the efficacy of ridge preservation in the maintenance of the residual alveolar ridge dimension beyond 6 months after treatment is unknown. The purpose of this study was to compare the differences in alveolar ridge dimensional change following ridge preservation between 4- and 12-month healing time points using cone-beam computed tomography (CBCT). Fifty seven patients planned for tooth extraction and implant placement were enrolled. Following extraction, ridge preservation was performed. CBCT scans were taken within 72hours following extraction with a customized resin stent containing a fixed radiographic marker. At either 4 months (short-term, ST group) or 12 months (long-term, LT group) after ridge preservation, patients had a second CBCT taken and an implant placed. Changes in ridge height and width were measured using the standardized radiographic marker. No significant differences were detected between the ST and LT groups in loss of buccal and lingual ridge height. Similarly, when adjusted for baseline ridge width, no significant differences were detected in ridge width loss at 3, 5, and 7mm apical to the crest between the ST and LT groups. The efficacy of ridge preservation in the maintenance of ridge width and height at the 12-month time point is similar to that of the 4-month time point. Clinicians may feel confident that a delay in implant placement for up to a year has no significant negative impact on the height and width of the healed ridge.

Theoretical Overturning Analysis of a 2.6-kW Two-Row Walking-Type Automatic Pepper Transplanter

Overturning on uneven and sloped surfaces is an important issue during the operation of agricultural field machinery. In this study, the geometrical (size and location) parameters of a pepper transplanter under development were optimized by theoretical overturning analysis to maintain stability during the operation. A walking-type transplanter was designed to transplant pepper seedlings in a two-row cultivation pattern so that the transplanting could be completed using three primary mechanisms for seeding, i.e., supply, picking, and dibbling. The four-wheel transplanter was designed to work with three different forward speeds (i.e., 0.3 m/s, 0.65 m/s, and 1.3 m/s). Mathematical and 3-D models were constructed both for static and dynamic conditions, and simulation was performed using a commercial software package to minimize the overturning tendency of the transplanter. Considering the plant ridge height and width, the track width and wheelbase of the transplanter were determined to be 725 mm and 680 mm, respectively. The positions of the mechanisms were optimized to maintain the center of gravity (CG) of the transplanter in the middle point of the stability area with a 436.26 mm height from the ground. During the static analysis, the transplanter was overturned laterally and longitudinally at slope angles of 40.67° and 36.26°, respectively. The transplanter overturned when the angles exceeded 29.3° for uphill and 49° for downhill paths, respectively, at the maximum forward speed (1.3 m/s) during dynamic analysis. Also, lateral overturning occurred while one wheel was exposed to obstacles with heights greater than 245 mm at the maximum operating speed. The results of this study would be helpful for designing the layout of the transplanter and the field test of the prototype.

Improving Productivity of Misaligned Boring of Hydraulic Cylinder Holes with a Rotating Cutter Block Based on Computer Simulation Results

The analysis of existing processing methods was carried out. A series of virtual experiments was performed; based on their results dependences of the height of residual ridges, the temperature on the workpiece surface and the temperature in the cutting zone on the parameters of the processing mode when boring internal holes with a rotating cutter block were constructed based on the results of virtual computer simulation. An optimization model of the boring process was built. The objective function was received. Within the optimization model framework, solutions were obtained that allow, at the highest value of axial feed, to ensure the required surface quality and avoid changes in the physical and mechanical properties of the material.

The foehn effect during easterly flow over Svalbard

Abstract. This article presents a comprehensive analysis of the foehn episode which occurred over Svalbard on 30–31 May 2017. This episode is well documented by multiplatform measurements carried out during the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) and Physical feedbacks of Arctic PBL, Sea ice, Cloud And AerosoL (PASCAL) campaigns. Both orographic wind modification and foehn warming are considered here. The latter is found to be primarily produced by the isentropic drawdown, which is evident from observations and mesoscale numerical modeling. The structure of the observed foehn warming was in many aspects very similar to that for foehns over the Antarctic Peninsula. In particular, it is found that the warming was proportional to the height of the mountain ridges and propagated far downstream. Also, a strong spatial heterogeneity of the foehn warming was observed with a clear cold footprint associated with gap flows along the mountain valleys and fjords. On the downstream side, a shallow stably stratified boundary layer below a well-mixed layer formed over the snow-covered land and cold open water. The foehn warming downwind of Svalbard strengthened the north–south horizontal temperature gradient across the ice edge near the northern tip of Svalbard. This suggests that the associated baroclinicity might have strengthened the observed northern tip jet. A positive daytime radiative budget on the surface, increased by the foehn clearance, along with the downward sensible heat flux provoked accelerated snowmelt in the mountain valleys in Ny-Ålesund and Adventdalen, which suggests a potentially large effect of the frequently observed Svalbard foehns on the snow cover and the glacier heat and mass balance.