Shaft Location Research Articles

Enhancement of needle visualization and localization in ultrasound.

This scoping review covers needle visualization and localization techniques in ultrasound, where localization-based approaches mostly aim to compute the needle shaft (and tip) location while potentially enhancing its visibility too. A literature review is conducted on the state-of-the-art techniques, which could be divided into five categories: (1) signal and image processing-based techniques to augment the needle, (2) modifications to the needle and insertion to help with needle-transducer alignment and visibility, (3) changes to ultrasound image formation, (4) motion-based analysis and (5) machine learning. Advantages, limitations and challenges of representative examples in each of the categories are discussed. Evaluation techniques performed in ex vivo, phantom and in vivo studies are discussed and summarized. Greatest limitation of the majority of the literature is that they rely on original visibility of the needle in the static image. Need for additional/improved apparatus is the greatest limitation toward clinical utility in practice. Ultrasound-guided needle placement is performed in many clinical applications, including biopsies, treatment injections and anesthesia. Despite the wide range and long history of this technique, an ongoing challenge is needle visibility in ultrasound. A robust technique to enhance ultrasonic needle visibility, especially for steeply inserted hand-held needles, and while maintaining clinical utility requirements is needed.

RESEARCH OF IMPACT OF THE VERTICAL FLOW ON THE DOWNSTREAM OF THE PIPE

The results of an experimental study of the factors influencing the velocity distribution in the trapezoidal outlet channel along a vertical shaft combined with a horizontal pipe are presented. Two schemes of construction were considered separately: scheme 1 with the location of the vertical shaft at a distance of less than 2/3 of the pipe length; schema 2 with the location of the shaft at the end of the main pipe. The model was studied the distribution of averaged, surface and bottom velocities in the outlet channel. The study confirmed the theoretical conclusion and found that the nature of the velocity distribution, both vertically and plan are functions of water depth in the channel and velocity in the outlet section of the pipe and are independent from the flow ratio in the horizontal pipe and the vertical shaft, except of the case placing the vertical tube on the end of the horizontal pipe.As a result of the mathematical processing of the experimental data, empirical equations of the lengths of the transformed sections of the bottom and surface averaged flow velocities were developed for different values of the dimensionless flow parameter depending on the water level of the outlet channel.

The Hypospadias Phenotype With A Distal Meatus In The Presence Of Distal Penile Penoscrotal Angle Fixation.

ObjectiveHypospadias patients may present with the phenotype that features the migration of scrotum to distal penile shaft below a coronal/subcoronal meatus. Patients with this phenotype differ widely in the severity of the hypospadias and the complexity of the surgical repair. We aimed to investigate the operative findings and the outcomes of consecutive patients who presented with this phenotype.MethodsWe retrospectively reviewed the medical charts of 31 consecutive patients who underwent hypospadias repairs from January 2014 to May 2017, and the hypospadias was characterized by i) the external urethral meatus at coronal/subcoronal region, ii) scrotal skin encroaching distally resulting in fixation of penoscrotal angle at distal penile shaft, and iii) urethral plate below the glans on penile shaft invisible or barely visible.ResultsThe median age at the time of surgery was 15.5 months (10–63). The division of corpus spongiosum was noted at distal penile shaft (n=2; 6.5%), mid-shaft (n=5; 16.1%) and proximal location (n=24; 77.4%). The median ventral curvature before degloving was 45 degrees (10–90). Twenty-eight and 3 patients underwent tubularized incised plate and 2-stage preputial flap repairs, respectively. Twenty-nine of 31 patients required cutback of the hypoplastic urethra. At the time of urethroplasty, 2 (6.5%), 7 (22.6%) and 22(70.9%) patients underwent distal, mid-shaft and proximal repairs, respectively. At a median follow-up of 30 months (14–50), 6 (19.4%) patients developed one or more complications (fistula=3; meatal stenosis=5).ConclusionPatients affected by this particular phenotype likely require non-distal hypospadias repair with possibly higher complication rate and should be treated by surgeons with expertise in complex hypospadias repair.

A numerical study on the effects of naturally ventilated shaft and fire locations in urban tunnels

SummaryIn more and more tunnels, natural ventilation mode with vertical shafts has been gradually employed. However, there are few studies investigating the influences of fire and shaft positions on natural ventilation performance currently. Therefore, this study investigated the effects of the transverse distance from fire source to tunnel sidewall, the longitudinal distance from fire source to shaft, and the transverse distance from shaft to sidewall on natural ventilation effectiveness in a tunnel fire by using Fire Dynamics Simulator. The typical characteristic parameters of smoke, such as mass flow rate, temperature distribution, and velocity vector were analyzed; besides, the phenomenon of plug‐holing was discussed. The results have shown that the mass flow rate of gas exhausted by the shaft decreases slightly with the increase of longitudinal distance from fire source to shaft. When the longitudinal distance from fire source to shaft is constant, changing the transverse distance from shaft to sidewall will have a more obvious effect on the effectiveness of exhausting smoke than changing the transverse distance from fire source to sidewall; in addition, the phenomenon of plug‐holing is more serious when the shaft is close to the sidewall.

Evaluation of shaft locations in underground mines: Fuzzy multi-objective optimization by ratio analysis with fuzzy cognitive map weights

Evaluation of shaft locations in underground mines: Fuzzy multi-objective optimization by ratio analysis with fuzzy cognitive map weights

Determination of main vertical ore-lift shaft location in two planes

A method of determination of main vertical ore-lift shaft location considering the difference between freight traffics is presented. The method is based on the rule of academician L D Shevyakov: “When freights are concentrating on one line and considering the minimum transportation work the main vertical ore-lift shaft must be located in a place of concentrating of this freight. If this freight would be summed with all the freights from the left, the result would be more than the freights from the right. If this freight would be summed with all the freights from the right, the result would be more than the freights from the left”.

291 Gray-scale ultrasound to assess persistent erectile dysfunction in young men

Young men exposed to 5 alpha reductase inhibitor (5ARI) finasteride for androgenic alopecia have reported persistent erectile dysfunction (PED). We are unaware of studies assessing their PED pathophysiology. Animals exposed to 5ARI have revealed both prostate smooth muscle and penile smooth muscle cell atrophy and apoptosis. High resolution gray-scale ultrasound (GSU) imaging is an efficient, non-invasive technique to assess cavernosal erectile tissue fibrosis (CETF) in men with ED. In selected men with PED from finasteride, high resolution GSU during maximal pharmacologic smooth muscle relaxation was used to better understand the pathophysiology. A renowned penile ultrasound expert (MB) blindly reviewed high resolution GSU images. Under IRB approval, charts of 27 men with PED (mean age 31) met inclusion/exclu-sion: potent prior to finasteride use; <40 years old with no obvious cardiovascular risk factors; underwent high resolution GSU/color duplex Doppler ultrasound with a high frequency probe (Aixplorer 15.4 MHz transducer) during maximal pharmacologic erection. GSU was performed in axial B-mode at multiple gains, with various dynamic ranges, in multiple penile shaft locations, to determine presence/absence of erectile tissue homogeneity or observation of heterogeneous regions. Color Doppler parameters of peak systolic velocity (PSV) and end-diastolic velocity (EDV) were also assessed. Ten control subjects with ED not exposed to finasteride who had erectile tissue homogeneity on high resolution GSU were also reviewed blindly by the ultrasound expert.

Analysis of unlined pressure shafts and tunnels of selected Norwegian hydropower projects

Norwegian hydropower industry has more than 100 years of experiences in constructing more than 4000 km-long unlined pressure shafts and tunnels with maximum static head of 1047 m (equivalent to almost 10.5 MPa) reached at unlined pressure tunnel of Nye Tyin project. Experiences gained from construction and operation of these unlined pressure shafts and tunnels were the foundation to develop design criteria and principles applied in Norway and some other countries. In addition to the confinement criteria, Norwegian state-of-the-art design principle for unlined pressure shaft and tunnel is that the minor principal stress at the location of unlined pressure shaft or tunnel should be more than the water pressure in the shaft or tunnel. This condition of the minor principal stress is prerequisite for the hydraulic jacking/splitting not to occur through joints and fractures in rock mass. Another common problem in unlined pressure shafts and tunnels is water leakage through hydraulically splitted joints or pre-existing open joints. This article reviews some of the first attempts of the use of unlined pressure shaft and tunnel concepts in Norway, highlights major failure cases and two successful cases of significance, applies Norwegian criteria to the cases and reviews and evaluates triggering factors for failure. This article further evaluates detailed engineering geology of failure cases and also assesses common geological features that could have aggravated the failure. The minor principal stress is investigated and quantified along unlined shaft and tunnel alignment of six selected project cases by using three-dimensional numerical model. Furthermore, conditions of failure through pre-existing open joints by hydraulic jacking and leakage are assessed by using two-dimensional fluid flow analysis. Finally, both favorable and unfavorable ground conditions required for the applicability of Norwegian confinement criteria in locating the unlined pressure shafts and tunnels for geotectonic environment different from that of Norway are highlighted.

Generating Vectored Thrust With the Rotational Paddling Gait of an ePaddle-EGM Mechanism: Modeling and Experimental Verifications

An eccentric paddle mechanism based on the epicyclic gear mechanism (ePaddle-EGM), proposed to enhance the mobility of amphibious robots for multiterrains tasks, can execute several terrestrial and aquatic gaits. In this paper, we rectify the experimental setup as well as the thrust modeling to do further research on rotational paddling gait. The effects of the rotational period and the location of paddle shaft to the thrust are analyzed. Besides the amplitude features, experimental results also illustrate the vector character of thrust generated by the rotational paddling gait.

Failure Analysis of AISI 440C Steel Ball Screws Used in the Actuator System of a Satellite Launch Vehicle

In view of its excellent wear and corrosion resistance, AISI 440C steel is the material of choice for the fabrication of ball screws used in actuator systems of satellite launch vehicles. During the routine acceptance test of a ball screw, longitudinal cracks were observed at the shaft location of the ball screw. The optical microstructure of the ball screw material (AISI 440C) revealed the presence of aligned carbides (carbide banding). Fractographic observations revealed the cracking to be along the carbide bands. Based on detailed optical and scanning electron microscopic observations, the cracking of the ball screws was attributed to the carbide bands.

THE OSKAR LIGNITE MINE IN SMOGÓRY (LUBUSZ LAND, WESTERN POLAND)

The paper presents history of one of the largest mines in the Lubusz Land, namely the Oskar Mine in Smogóry near Ośno Lubuskie. The mine operated between 1860 and 1945 under the name of Oskar and later as Smogóry until 1961. The paper focuses on the detailed pre-war history of the Oskar Mine, shows its mining area, location of shafts and descending galleries. Available data about the amount of extraction and employment level are presented. The paper is based on remaining German archived materials (Main Mining Office) and on Polish documents. The paper describes briefly the discovery of lignite deposits in the 19th century near Ośno Lubuskie. Underground room and pillar retreat mining used in this mine is also characterized. Complicated lignite bed structure, ­resulting from geological conditions (glaciotectonic deformation), is discussed. The geological structures is illustrated by a few geological cross-sections.

Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis

The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge–Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect.

Relevance and prospect of development of imitating modelling at research of working process of the excavator

A scraper design with rotary loading. Substantiates the location of the rotor blades to provide a bucket load and complete unloading. The question of filling the bucket scraper height and location of the rotor shaft to operate the scraper without pusher. Presented calculated according to the definition of the scraper bucket capacity with the rotor load, the radius of the rotor circumference and the height of the side walls of the bucket. The recommendations of the angle of inclination of the rear wall of the bucket to the vertical and location podnozhevoy plate.

Hydrochemical disturbances measured in groundwater during the construction and operation of a large-scale underground facility in deep crystalline rock in Japan

Changes in the hydrochemical conditions of groundwater were evaluated following the construction of a large-scale underground facility at the Mizunami Underground Research Laboratory (MIU), Japan. The facility was constructed to a depth of 500 m in sedimentary and granitic rocks. Drawdown of the groundwater level in the range of several tens to hundreds of meters was observed up to hundreds of meters away from the shafts during the first ten years of facility construction and operation. Subsequent changes in groundwater chemistry occurred due to upconing of high-salinity groundwater from the deepest part of the shaft and the infiltration of low-salinity shallow groundwater. We predict that future deep groundwater chemistry in the vicinity of the MIU facility will resemble that of the present-day shallow groundwater. Multivariate statistical analysis provides fundamental insights into such a site. We found that the extent of hydrochemical variability related to MIU construction and operation was dependent on the distance from the facility shafts and galleries and on hydrogeological compartmentalization resulting from lithological boundaries (such as permeable conglomerates vs. more compact lithological units) and other features (such as faults or clay layers). We conclude that hydrochemical impact assessment of groundwater in low-permeability rock is essential prior to the construction of such a facility. This should include characterization of hydrogeological structures and compartments to propose suitable location of shafts and galleries.

Development and Validation of Statistical Models of Femur Geometry for Use with Parametric Finite Element Models.

Statistical models were developed that predict male and female femur geometry as functions of age, body mass index (BMI), and femur length as part of an effort to develop lower-extremity finite element models with geometries that are parametric with subject characteristics. The process for developing these models involved extracting femur geometry from clinical CT scans of 62 men and 36 women, fitting a template finite element femur mesh to the surface geometry of each patient, and then programmatically determining thickness at each nodal location. Principal component analysis was then performed on the thickness and geometry nodal coordinates, and linear regression models were developed to predict principal component scores as functions of age, BMI, and femur length. The average absolute errors in male and female external surface geometry model predictions were 4.57 and 4.23mm, and the average absolute errors in male and female thickness model predictions were 1.67 and 1.74mm. The average error in midshaft cortical bone areas between the predicted geometries and the patient geometries was 4.4%. The average error in cortical bone area between the predicted geometries and a validation set of cadaver femur geometries across 5 shaft locations was 2.9%.

Modeling of a Transient Event in the Tunnel and Reservoir Plan System in Chicago, Illinois

Transient flow events can potentially damage infrastructure and threaten public safety in the vicinity of violent flow eruptions that occur where tunnel drop shafts interconnect with the surface-combined sewer system. Transient events have been observed in tunnels and at drop shafts in the tunnel and reservoir plan (TARP) system in Chicago on a number of occasions since operations first began in 1985. For the most part, the phenomenon has been controlled effectively by operating the system in a conservative mode through controlling the rate of filling. Nevertheless, more recently, not only water transients but also geysering events—the intermittent discharge of a combination of water and air from a hydraulic system—have occurred at the terminus of branch tunnels where controlled filling is not effective. The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC), the operating agency for the system, has been prompted to develop engineering solutions to minimize transient flow occurrence and negative effects at the affected drop shaft locations. To this end, numerical modeling was conducted to investigate the cause and potential solutions. Such modeling included one-dimensional (1D) hydraulic transient modeling of a large domain in the system, followed by more detailed three-dimensional (3D) two-phase flow simulations within a smaller domain. The 1D approach revealed the interaction between localized events of interest and other transient flow features that originate far from the drop shaft under consideration. Computational fluid dynamics (CFD) modeling results show the complex interaction of trapped air and water in the tunnels. Even though more field observations are needed to test the accuracy of model predictions, careful interpretation of the results made it possible to pinpoint the problem and propose a solution. The findings also provided insight into the importance of considering both inertial instabilities as well as air–water interactions in geysering mechanics.

Multi-variable selection of the main mine shaft location

Selecting the location of the main mine shaft is a demanding multi-criteria task. The solution does not depend only on identification of the potential location for the construction and the criteria conditions set for the selection, but also on the applied procedure in the analysis. Since there is no general scientific agreement on the selection of the most suitable quantitative method for the support to decision making for this type of analyses, the problem is becoming even more complex. In terms of the Velenje Mine shaft location, the authors describe the approach that can be an exit from this situation. The idea of an approach is not the selection of the most suitable decision making support method but a multi-model procedure where several multi-criteria methods are being used simultaneously. In case when the techniques do not yield the same order of alternatives, it is advised to generate the final order using the method of ponderation.

Influence of mechanical ventilation-shaft connecting location on subway tunnel ventilation performance

Subways are widely used for public transportation in major cities and require efficient ventilation systems to maintain indoor air quality in the subway tunnel. A subway tunnel was investigated to understand the airflow inside the tunnel, and to improve its ventilation system. The steady three-dimensional airflow in the tunnel was analyzed using ANSYS CFX software to solve Reynolds-averaged Navier–Stokes equations. The ventilation performance in the subway tunnel was investigated with respect to the connecting location of the mechanical ventilation shaft by analyzing mass flow rate through the ventilation-shafts and the airflow in the tunnel. The airflow in the tunnel and the mass flow rate in the shafts were investigated when the guide-vane, the porous zone and the air-curtain were installed in the subway tunnel system. The discharged-air was higher at ventilation-shaft 2 which was connected to the top wall of the tunnel than that of the ventilation-shaft 1 which was connected to the side wall of the tunnel. The numerical results suggested the connecting location of shaft 2 as the optimum connecting location.

A numerical analysis of airflows caused by train-motion and performance evaluation of a subway ventilation system

A numerical analysis of airflows caused by train-motion in one-shaft subway system and two-shaft subway system was carried out using computational fluid dynamics (CFD) method. The dynamic mesh method was used to model the moving boundaries of the train. The geometry model and train-operation schedule employed were exactly the same as the real situation. The CFD model was validated against field measurement data. The performance of natural ventilation system impacted by the location and number of the vent shafts was evaluated by two indexes, i.e. net exhaust air volume, Ne, and net suction air volume, Ns. The result shows that a subway system with two shafts rather than that with one shaft could dramatically improve performance in air exchange efficiency. For the one-shaft system, it performed better when the shaft was located at the train-arrival side rather than at train-departure side.

Incidence and demography of femur fractures with and without atypical features

The case definition, community incidence, and characteristics of atypical femoral shaft fractures (FSFs) are poorly understood. This retrospective study utilized electronic medical records and radiograph review among women ≥50 years of age and men ≥65 years of age from January 1996 to June 2009 at Kaiser Permanente Northwest to describe the incidence rates and characteristics of subgroups of femur fractures. Fractures were categorized based on the American Society for Bone and Mineral Research (ASBMR) as atypical fracture major features (AFMs) (low force, shaft location, transverse or short oblique, noncomminuted) and AFMs with additional minor radiograph features (AFMms) (beaking, cortical thickening, or stress fracture). There were 5034 fractures in the study. The incidence rates of FSFs (without atypical features) and AFMs appeared flat (cumulative incidence: 18.2 per 100,000 person-years, 95% CI = 16.0-20.7; 5.9 per 100,000 person-years, 95% CI = 4.6-7.4; respectively) with 1,271,575 person-years observed. The proportion of AFMs that were AFMms increased over time. Thirty percent of AFMs had any dispensing of a bisphosphonate prior to the fracture, compared to 15.8% of the non-atypical FSFs. Years of oral glucocorticosteroid dispensing appeared highest in AFM and AFMm fractures. Those with AFMs only were older and had a lower frequency of bisphosphonate dispensing compared to those with AFMms. We conclude that rates of FSFs, with and without atypia, were low and stable over 13.5 years. Patients with only AFMs appear to be different from those with AFMms; it may be that only the latter group is atypical. There appear to be multiple associated risk factors for AFMm fractures.