Vertical Reduction Research Articles

Design of low profile high gain antenna using loop-based wideband artificial magnetic conductor for UWB applications

AbstractIn this work, a low profile ultra-wideband (UWB) antenna is designed and investigated using a novel loop-based wideband artificial magnetic conductor (WB-AMC) for gain enhancement. Initially, a compact loop antenna is designed using stub loading and further optimized for the UWB range by applying curve ground methodology. The average gain of the proposed antenna without WB-AMC is 2.7 dBi. To enhance the gain of the entire UWB range, loop-based WB-AMC in [2 × 2] forms is integrated. WB-AMC is used as a ground plane beneath the antenna. To validate the performance, the UWB antenna and WB-AMC are fabricated and tested. The measured results confirm the entire UWB range. Proposed antenna provides a peak gain of 9.4 dBi and an average gain of 5.8 dBi. Vertical profile reduction of 50% is achieved compared to perfect electric conductor ground. The proposed UWB antenna is a potential candidate for UWB wireless applications due to its attractive features such as low profile, wide bandwidth coverage, omnidirectional pattern, constant high gain, and group delay.

Sagittal reduction genioplasty: Technical note

Without a doubt, the chin plays an important role on facial harmony. Both position and shape of the chin can significantly affect the facial profile. Genioplasty is a relatively simple surgical procedure that allows to correct deformities associated to the chin area. Several techniques and modifications have been described in the literature for different types of deformities. Anterior posterior reduction osteotomies of the chin have an unpredictable effect on the soft tissues and the use of the conventional sliding osteotomy have shown unsatisfactory cosmetic outcomes, this associated with step deformity, notching at the inferior border of the mandible among others. We propose a simple and effective technique that allows the correction of a chin deformity in cases where sagittal or vertical reduction is required with excellent esthetic results. Four case examples are presented for technique illustration.

Investigation on Vertical Stiffness Reduction of Thick Rubber Bearings Under Lateral Displacement

Investigation on Vertical Stiffness Reduction of Thick Rubber Bearings Under Lateral Displacement

Cone-beam computed tomographic evaluation of dimensional hard tissue changes following alveolar ridge preservation techniques of different bone substitutes: a systematic review and meta-analysis.

PurposeThis study was conducted to evaluate and compare the effects of different graft materials used in alveolar ridge preservation on dimensional hard tissue changes of the alveolar ridge, assessed using cone-beam computed tomography (CBCT) scans.MethodsA systematic electronic search of MEDLINE and the Cochrane Central Register of Controlled Trials and a manual search were conducted from November 2019 until January 2020. Randomized controlled trials were included if they assessed at least 1 variable related to vertical or horizontal hard tissue changes measured using CBCT scans. After a qualitative analysis of the included studies, subgroups were formed according to the graft material used, and a quantitative analysis was performed for 5 outcome variables: changes in vertical alveolar bone height at 2 points (midbuccal and midpalatal/midlingual) and changes in horizontal (buccolingual) alveolar bone width at 3 different levels from the initial crest height (1, 3, and 5 mm).ResultsThe search resulted in 1,582 studies, and after an independent 3-stage screening, 16 studies were selected for qualitative analysis and 9 for quantitative analysis. The meta-analysis showed a significantly (P<0.05) lower reduction of alveolar ridge dimensions for the xenogenic subgroup than in the allogenic subgroup, both vertically at the midbuccal aspect (weighted mean difference [WMD]=−0.20; standard error [SE]=0.26 vs. WMD=−0.90; SE=0.22) as well as horizontally at 1 mm (WMD=−1.32; SE=0.07 vs. WMD=−2.99; SE=0.96) and 3 mm (WMD=−0.78; SE=0.11 vs. WMD=−1.63; SE=0.40) from the initial crest height. No statistical analysis could be performed for the autogenic subgroup because it was not reported in sufficient numbers.ConclusionsLess vertical and horizontal bone reduction was observed when xenogenic graft materials were used than when allogenic graft materials were used; however, the loss of alveolar ridge dimensions could not be completely prevented by any graft material.

Dynamic Characteristics of Metro Vehicle under Thermal Deformation of Long-Span Cable-Stayed Bridge

In order to study the influence of thermal deformation of long-span cable- stayed bridge (LSCSB) on the dynamic characteristics of metro vehicle on the bridge, based on the theory of vehicle-track coupled dynamics, the rigid-flexible coupled dynamic model of metro vehicle-track-LSCSB system is established by using finite element method and multi-rigid-body dynamics. Adopting this model, the deformation of LSCSB subject to temperature is analyzed, then the comprehensive effect of track random irregularity and rail deformation caused by temperature load is considered to study the dynamic characteristics of metro vehicle running through the bridge, and finally the influences of temperature increment and running speed on concerned dynamic indices of vehicle are studied. The results show that the LSCSB deforms obviously subject to temperature load, and the overall performance is that the cooling is arched, and the heating is bent, and the shape variable changes almost linearly with the temperature load. According to the parameters studied in this paper, the rail deformation caused by temperature load increases the wheel-rail vertical force, derailment coefficient and wheel load reduction rate by 1.5%, 3.1% and 5% respectively. The vertical acceleration of the vehicle body decreases by 2.4% under the cooling condition, while increases by 3.7% under the heating condition. The dynamic response of the bridge changes under temperature load. The maximum vertical and horizontal displacement in the middle of the main beam span are 6.24 mm and 2.19 mm respectively, and the maximum vertical and horizontal acceleration are 1.29 cm/s2 and 2.54cm/s2 respectively. The derailment coefficient and vertical acceleration of vehicle body are more affected by temperature load, and the wheel load reduction rate and wheel-rail vertical force are more affected by speed. The conclusion of this paper provides a reference for subsequent scholars to study the influence of thermal deformation on the dynamic response of vehicles on LSCSB.

Plastic and reconstructive breast surgery techniques in the surgical treatment of idiopathic granulomatous mastitis: a single-center experience

Idiopathic granulomatous mastitis (IGM) is a chronic inflammatory breast disease with unknown cause and undefined treatment. Since it has a high recurrence rate, wide excisions are recommended for surgical treatment. This study aims to discuss the selection and outcomes of plastic and reconstructive breast surgery techniques following wide excision. This study examines the prospectively recorded surgical outcomes of 18 patients who were diagnosed with IGM between 2020 and 2022. Following histopathological confirmation of all patients' diagnoses, the most appropriate technique was used in conjunction with wide surgical excision. Preoperative standing drawings were made for all patients and operations were performed by the same surgical team under general anesthesia. All patients were monitored for 6 months for postoperative complications, recurrence, and aesthetic outcomes. The patients underwent surgery for recurrence (n = 8), recurrent abscess (n = 4), and persistent disease (n = 6), in that order. Patients were treated with dermoglandular flap transposition (n = 6), Wise pattern reduction mammoplasty (n = 3), vertical reduction skin incision (n = 3), inferior pedicle with Wise pattern reduction mammoplasty (n = 4), and free nipple reduction mammoplasty (n = 2) techniques following partial mastectomy. No major complications developed postoperatively. Two patients with recurrence benefited from topical steroid injections. A wide excision is required to prevent IGM recurrence during surgery. After wide excision, the simplest and most easily applicable plastic and reconstructive breast surgery techniques can yield successful results with acceptable complication and recurrence rates. In technique selection, we recommend an individualized surgical approach for effective patient management.

Realizing mutual occlusion in a wide field-of-view for optical see-through augmented reality displays based on a paired-ellipsoidal-mirror structure

Mutual occlusion is an essential feature for augmented reality (AR) displays for allowing the virtual content to be clearly perceived under an excessively illuminated environment. Although a few works have been done to facilitate the performance of occlusion-capable optical see-through augmented reality (OC-OST-AR) displays, the realization of mutual occlusion in a wide field-of-view (FOV) is still challenging. Divergent from typical hard-edge occlusion and soft edge-occlusion designs, we propose the paired-ellipsoidal-mirror (PEM) structure. The proposed system is allowed to support either hard-edge occlusion or enhanced soft-edge occlusion in a wide FOV by optionally fixing a spatial light modulator (SLM) before the entrance pupil or at an inner focal plane. The numerical aperture (NA) of the system is efficiently increased by the combination of paired ellipsoidal mirror imaging and aperture stop restriction. With proof-of-concept prototypes built, virtual display in a FOV of H160°×V74° and mutual occlusion in a FOV of H122°×V74° are demonstrated with a basic design, respectively. Furthermore, a mixed FOV of H95.3°×V52.9° is demonstrated by an optimized design with vertical parallax reduction and virtual display improvement.

Edge crack damage analysis of AZ31 magnesium alloy hot-rolled plate improved by vertical roll pre-rolling

In the present study, through vertical roll pre-rolling of AZ31 magnesium alloy hot-rolled plate at room temperature, the effect of different vertical roll pre-rolling reduction on edge crack of the plate during flat rolling was systematically studied. The evolution of microstructure and texture in the edge and middle of the plate after vertical roll pre-rolling, heating and rolling was analyzed by using EBSD technology. The results show that during the vertical roll pre-rolling, {10–12} primary twins and {10–12}-{10–12} secondary twins dominated the edge deformation, while {10–12} primary twins dominated the middle deformation. With the increase of vertical roll pre-rolling reduction, the twin volume fraction of the edge and the middle increased, and the difference between them decreased gradually. After heating, the twin orientation caused by vertical roll pre-rolling was still maintained, and there was a significant difference in grain size between the edge and the middle. When the reduction rate of flat rolling was 30%, cracks have already appeared in the initial plate, while the vertical roll pre-rolled samples showed extremely high rolling performance. When the reduction rate of flat rolling was 50%, the 8PR sample still had no crack initiation. In addition, after flat rolling of 50%, the initial plate showed a strong basal texture, while the maximum pole density of the 8PR plate was small, and the texture distribution was very scattered, showing the characteristics of weak orientation.

Dynamic modeling and analysis of vertical vibration reduction system for passenger train

Based on wheel-rail impact vibration and considering the body stiffness and natural damping, this paper builds a four-degree-of-freedom vibro-impact system model for passenger train’s vertical vibration reduction system. The Poincaré map of the system is determined by the analytic solution of the system derived from the motion differential equation of the multi-degree-of-freedom vibro-impact system combined with Newton's second law. It is found that the fork bifurcation, Hopf bifurcation and other dynamical behavior leading to Chaos when the system parameters are changed. On this basis, the dynamic parameters of the train are optimized to avoid chaos in the train operation, reduce the vertical vibration of the train, improve the stability and comfort of the train operation, and provide the theoretical basis for the active vibration reduction design of the train.

Determination of Tropospheric Parameters from ERA Surface Data for Space Geodetic Techniques

This study investigates methods of deriving meteorological parameters needed in space geodetic applications, from the surface data of the numerical weather model (NWM). It is more efficient than pressure level data in terms of storage and transmission. Based on more realistic assumptions for the structure of the troposphere, formulas for accurate vertical reduction of pressure (P) and precipitable water vapor (PWV) are deduced, and they are applied with the gridded lapse rate data provided by the GPT2w model. The new method achieves better accuracy especially when a large height difference between the grid point and station exists. Validation with global radiosonde observations shows that the RMS errors of P, temperature (T), and water vapor pressure (e) derived from 2.5° × 2.5° ERA surface data are 1.16 hPa, 1.95 K, and 1.76 hPa respectively; zenith tropospheric delays (ZTDs) calculated from derived P, T, and e values have a mean RMS error of 3.26 cm, comparable to that obtained from in situ measurements; adding PWV will increase ZTD estimation accuracy to 1.52 cm, comparable to that obtained from NWM pressure level data. Validations with Global Navigation Satellite System estimated ZTDs from global and regional station networks display similar results on the globe, as well as features for localized regions. Using higher spatial resolution NWM seems to have little effect on the accuracy of ZTDs calculated from P, T, and e, while it apparently improves the accuracy of ZTDs calculated from P, T, e, and PWV.

The Passot Technique Revisited: No Vertical Scar Reduction Mammoplasty in Unmarried Females: A Case Series.

BACKGROUNDMacromastia in adolescent girls is a distressing condition. There is an increase in the number of patients opting for reduction mammoplasty in the late teens. The semicircular horizontal method of breast reduction, first described by Passot in 1925 has the advantage of being able to do larger reduction, particularly suitable for pendulous breasts and having a hidden scar in the inframammary fold.METHODSEleven patients of adolescent macromastia were included in this study. It was conducted over a period of 4 years (2013-17) at two teaching institutions in Kolkata and Rishikesh, India. The mean age of the patients was 19.2 years. The Passot technique of reduction mammoplasty was performed in each case and the volume of resected breast tissue recorded by weighing the specimen. The aesthetic outcome was assessed by Lowery scale (volume, contour, placement of the breast mound and inframammary fold). Patient satisfaction was assessed after 6 months of follow up on a scale of 1 to 10, where 1-4 was poor, 5-6 fair, 7-8 good and 9-10 excellent. RESULTSMean total reduction per breast was 856 gm. Patients reported a mean decrease of cup size by 1.5. The aesthetic outcome was excellent in 6 patients and good in 5 patients. Patient satisfaction was excellent in 9 patients and good in 2 patients.CONCLUSIONPassot technique is a safe and effective technique of reduction mammoplasty and is especially useful in adolescent macromastia where the absence of visible scar on the breasts is very satisfying for the patients.

Assessment of global wave forces and moments on porous vertical barriers in random wave fields

Experimental investigations were carried out to assess the global wave forces and wave induced moments on slotted vertical barriers (SVB). Fourty two different wave barrier configurations (5%, 10%, 20%, 30%, 40%, 50% and 60% porosities and 1 to 6 number of slotted walls) were tested in random wave fields of JONSWAP spectra for wide range of significant wave heights and peak periods. It is found that the wave force is very sensitive to the change in porosity of the SVB. It is also found that relatively long waves and low porosity on SVB results in the highest wave force and short waves and high porosity on the SVB results in the lowest wave force. For most of the conditions, the wave force on SVB is less than the wave force on a single impervious vertical wall and force reduction to an extent of 20% to 80% is possible for the range of porosity and number of porous walls studied. A predictive equation to estimate the wave induced significant moment is provided with high regression coefficient. The average lever arm for assessing the wave induced moment is 0.6145 times the local water depth.

Design and analysis of isolation effectiveness for three-dimensional base-seismic isolation of nuclear island building

In order to investigate the application of 3D base-seismic isolation system in nuclear power plants (NPPs), comprehensive analysis of constitution and design theory for 3-dimensional combined isolation bearing (3D-CIB) was presented and derived. Four different vertical stiffness of 3D-CIB was designed to isolate the nuclear island (NI) building. This paper aimed at investigating the isolation effectiveness of 3D-CIB through modal analysis and dynamic time-history analysis. Numerical results in terms of dynamic response of 3D-CIB, relative displacement response, acceleration and floor response spectra (FRS) of the superstructure were compared to validate the reliability of 3D-CIB in mitigating seismic response. The results showed that 3D-CIB can significantly attenuate the horizontal acceleration response, and a fair amount of the vertical acceleration response reduction of the upper structure was still observed. 3D-CIB plays a significant role in reducing the horizontal and vertical FRS, the vertical FRS basically do not vary with the floor height. The smaller the vertical stiffness of 3D-CIB is, the better the vertical isolation effectiveness is, whereas, it will increase the displacement and the rocking effect of superstructure. Although the advantage of 3D-CIB is that the vertical stiffness can be flexibly adjusted, it should be designed by properly accounting for the balance between the isolation effectiveness and displacement control including rocking effect. The results of this study can provide the technical basis and guidance for the application of 3D-CIB to engineering structure.

Review on Passenger Vehicle Car Body Dynamic Analysis

Vibration control in rail vehicles is critical for passenger comfort as well as infrastructure lifespan. Since rail vehicle vibration has such a big influence on railway infrastructure, it's crucial to figure out how to control it. Improved ride comfort is one of the benefits of vibration control. The contact stiffness between the rail track and the rail vehicle wheels is extremely high due to the steel-on-steel contact; this allows the rail vehicle to respond to track irregularities via vertical, lateral, or transversal displacements. Due to the rising demand for high-speed trains, solutions to isolate the reaction of rail cars to track irregularities must be developed, as increased speeds result in increased frequency of track irregularity-induced displacements. If the vibration frequencies are within the same range as the passengers' natural frequencies, increased displacement frequencies generate vibrations that negatively influence ride comfort. The purpose of this literature survey is to give an overview of previous studies regarding methods to passively or actively achieve vertical vibration reduction in a rail vehicle and improve the ride comfort for passengers.

The Passot Technique Revisited: No Vertical Scar Reduction Mammoplasty in Unmarried Females: A Case Series

The Passot Technique Revisited: No Vertical Scar Reduction Mammoplasty in Unmarried Females: A Case Series

Vertical financial disparity, energy prices and emission reduction: Empirical insights from Pakistan

The economic and environmental aspects of energy production have become important due to the increasing complexity energy sector and envoirnmental pollution, warranting to test the connection between financial imbalances, energy prices and carbon emission. The study aims to test the impact of vertical fiscal imbalances (VFI) on energy prices and carbon emission trends by considering the dual-perspectives of environmental regulation and industrial structure. The empirical outcomes indicated that vertical fiscal imbalances limited the environmental quality of Pakistan. Furthermore, VFI also caused environmental degradation by affecting industrial structure. VFI inhibits the intensity of environmental regulation, promotes the upgrade of industrial structures, both of which cause additional carbon emissions. The study suggest to energy ministries and energy regulation offices to revisit the machinism of energy prices determination and revised machanisim should provide a user-friendly assessment to understand the actual costs associated with the rising concern of environmental pollution. By this, envoirnmental protection maximization and optimal energy conservation is expacted to increase. Based on empirical findings, the study extends the suggestion that vertical fiscal imbalances should be considered an active indicator by the key policy makers and other stakeholders for energy prices determination and environmental quality upgradation.

A Review and Measurement Study of the Central Mound Pedicle for Breast Reduction.

Background:The central mound approach to breast reduction has been the subject of recent interest in the literature. However, quantitative evaluation using measurements is lacking. This review was undertaken to objectively evaluate changes in breast dimensions, and to compare the results to a popular alternative method, vertical mammaplasty.Methods:An electronic search was performed using PubMed to identify all publications endorsing the central mound technique. Published lateral photographs were matched for size and orientation, with computer assistance. Measurements included breast projection, upper pole projection, lower pole level, breast mound elevation, nipple level, and breast parenchymal ratio. Results were compared with published measurement data for the vertical technique.Results:Twenty-three manuscripts were identified. Ten included photographs suitable for analysis. On average, breast projection decreased 1.1 cm after central mound breast reduction (P < 0.05). Upper pole projection dropped 0.4 cm (not significant). The lower pole level was raised 2.6 cm (P < 0.05). The nipple level was over-elevated 0.6 cm, on average. The breast parenchymal ratio increased by 0.54. A central mound dissection decreased breast projection. In contrast, publications using a vertical breast reduction demonstrated maintenance of upper pole and breast projection and a modest (<1 cm) increase.Conclusions:For each measurement comparison, the vertical method outperforms the central mound. Because of its anatomy and geometry, measurements show that the vertical method for breast reduction is more favorable than a central mound dissection. This method can also be used safely for secondary breast reductions.

Can the ground enhance vertical force for inclined stroke plane flapping wing?

The numerical investigation of 2D insect wing kinematics in an inclined stroke plane is carried out using an immersed boundary solver. The effect of vortex shedding and dipole jet on the vertical force generation by the flapping wing due to change in the stroke plane angle is investigated in the vicinity of the ground. The results of instantaneous force and vorticity contours reveal the underlying lift enhancement mechanisms for the inclined stroke plane flapping wing. Moreover, they aid in the understanding of the wake-ground interaction and the associated shear layers. The calculated average vertical force delineates different force trends for the inclined stroke plane flapping near the ground. Furthermore, the dipole jet patterns are analyzed for different heights. These patterns are found to be a better tool to assess the kinematics for the vertical force enhancement and reduction, especially at intermediate heights. Vertical force enhancement is the critical parameter in the design of the micro aerial vehicle (MAV). Through this study, it is certain that the dipole jet has the potential to be used as a lift modification mechanism in MAVs. In summary, the study gives a holistic view of the physics of the inclined plane kinematics near the ground and serves as the basis for the design of MAVs.

Distribution channels (dc) in the technological industry - ideas for improvement in Argentina

For many years, the DC operation -covering massive sales and value added solutions- have been a reality in the Argentinean technological industry. Manufacturing companies have used them as a central part of their commercial growth/value added strategies to provide greater geographical coverage and adequacy to the products/services offered. As a result, this work shows different DC facets of this environment and possible improvement aspects. Management focus could bring better performance levels for the organizations that configure this complex and exciting industry. The hypothesis of this study –which was corroborated- is that there are aspects that can be improved in the DC operation of the Argentinean technological industry, bringing value added and sustainable growth to the companies’ network. Main findings of this work reveal that long DC and hybrid models are mostly used by manufacturers because they improve commercial reach, final customers’ solutions and purchase experience, providing the highest possible flexibility and profitability. It also requires cost optimization, channel efficiencies and vertical conflicts reduction. In addition, there are challenges connected to: a) the whole DC network value understanding and the optimal channel level mix, b) customer demand generation, c) the technology/cloud-based businesses and the SMB (Small Medium Business) that need more personalization and value added focus, d) remote channels/online platforms versus physical channels, e) the Opportunity Registration process as a way to protect the DC investment in certain key customers, and f) training opportunities, among others. The final objective referrers to get away from imitation and commoditization, proposing a unique value proposition for which strategy and marketing plans should create long term customer value. Finally, best practices are remarked as a way to evolve to new performance levels. The study is exploratory-descriptive, with a qualitative methodology, and it is supported with a bibliographical and an empirical analysis.

Healing of Post-Extraction Sockets Filled with Anorganic Bovine Bone and Covered with a Xenogeneic Collagen Matrix. Radiological 2D and 3D Results of a Pilot Study to Assess Dimensional Stability.

Analysis of short-term results regarding dimensional stability of post-extraction sockets managed via a preservation protocol using deproteinized bovine bone matrix and a xenogeneic collagen matrix. Materials and methods Fifteen patients needing extraction of one single-rooted premolar tooth were treated in a pilot study. Five patients were treated in each centre. After tooth extraction, sockets were filled with anorganic bovine bone matrix and covered with a xenogeneic collagen matrix. Six months later, implants were placed. Dimensional changes in the treated sites were digitally evaluated using the best-fit superimposition of pre-and post-socket preservation models. Results After six months of healing, the vertical reduction of the grafted sites was 0.31 ± 0.24 mm (p < 0.001). Volumetric analysis of superimposed models showed an average palatal-lingual contraction of 0.33 ± 0.51 mm3 (p = 0.02). At the vestibular level, the average contraction was found to be 0.8 ± 0.3 mm3 (p < 0.001). Finally, the analysis of linear variations in the treated sites on a single sagittal section at the crystal level, and at 3 and 7 mm apically respect to the crest, both towards the vestibule and palate, generally showed more marked resorption at the crestal level compared to apical measurements. Conclusion: The clinical protocol herein employed for socket preservation showed a positive effect in preventing the physiological post-extraction remodeling.