Laser Fiber Displacement Velocity during Tm-Fiber and Ho:YAG Laser Lithotripsy: Introducing the Concept of Optimal Displacement Velocity

Background: Endocorporeal laser lithotripsy (EL) during flexible ureteroscopy (URS-f) often uses “dusting” settings with “painting” technique. The displacement velocity of the laser fiber (LF) at the stone surface remains unknown and could improve EL’s ablation rates. This in vitro study aimed to define the optimal displacement velocity (ODV) for both holmium:yttrium-aluminium-garnet (Ho:YAG) and thulium fiber laser (Tm-Fiber). Methods: A 50W-TFL (IRE Polus®, Russia) and a 30W-MH1-Ho:YAG laser (Rocamed®), were used with 272µm-Core-Diameter LF (Sureflex, Boston Scientific©), comparing three TFL modes, “fine dusting” (FD:0.05–0.15 J/100–600 Hz); “dusting” (D:0.5 J/30–60 Hz); “fragmentation” (Fr:1 J/15–30 Hz) and two Ho:YAG modes (D:0.5 J/20 Hz, Fr:1 J/15 Hz). An experimental setup consisting of immerged cubes of calcium oxalate monohydrate (COM) stone phantoms (Begostone Plus, Begoã) was used with a 2 seconds’ laser operation time. LF were in contact with the stones, static or with a displacement of 5, 10 or 20 mm. Experiments were repeated four times. Stones were dried and µ-scanned. Ablation volumes (mm3) were measured by 3D-segmentation. Results: ODV was higher in dusting compared to fragmentation mode during Ho:YAG lithotripsy (10 mm/sec vs. 5 mm/sec, respectively). With Tm-Fiber, dusting and fragmentation OVDs were similar (5 mm/sec). Tm-Fiber ODV was lower than Ho:YAGs in dusting settings (5 mm/s vs. 10 mm/sec, respectively). Without LF displacement, ablation volumes were at least two-fold higher with Tm-Fiber compared to Ho:YAG. Despite the LF-DV, we report a 1.5 to 5-fold higher ablation volume with Tm-Fiber compared to Ho:YAG. Conclusions: In dusting mode, the ODVTm-Fiber is lower compared to ODVHo:YAG, translating to a potential easier Tm-Fiber utilization for “painting” dusting technique. The ODV determinants remain unknown. Dynamic ablation volumes are higher to static ones, regardless of the laser source, settings or LF displacement velocity.

Displacement Velocity and Strain Analysis of Opak Fault Monitoring Stations

The Opak Fault is an active fault that can potentially cause earthquakes in Yogyakarta. Periodic monitoring of the Opak Fault activity was previously used more GNSS observation data from the measurement campaign by the Geodesi Geometri dan Geodesi Fisis (GGGF) Laboratory Team, Geodetic Engineering Department, Faculty of Engineering, Universitas Gadjah Mada. However, there are several CORS BIG stations located in Yogyakarta. The CORS BIG data is used to increase the precision of the Opak Fault monitoring station. Therefore, the addition of the CORS is evaluated to obtain a displacement in the monitoring station. The computation of the displacement velocity value of the Opak Fault monitoring station has been done before using the Linear Least Square Collocation and grid search methods. The other method, namely the kriging method, needs to be evaluated for producing a more precise displacement velocity value. The research data includes GNSS campaign and CORS BIG data for six years, 2013 to 2020. The CORS stations around DIY are JOGS and CBTL. The GNNS data were processed to determine the solution for the daily coordinate, displacement, and standard deviation values for each Opak Fault monitoring station. The displacement velocity value is generated by the Linear Least Square method then reduced from the influence of the Sunda Block. The velocity value is used in the strain value estimation around the Opak Fault area at each station using the kriging method combined with the gaussian sequential simulation technique. The estimated displacement velocities are examined for statistical significance compared to the research of Adam (2019) and Pinasti (2019). This research generates the value of the displacement velocity in the east and north components of 12.39 to 30.99 mm/year and 1.96 to -14.11 mm/year, respectively. The displacement direction of all monitoring stations is dominant to the southeast. The Sunda Block reduced the displacement velocity. The east and north components are -2.32 to 2.28 mm/year and -0.52 to 4.2 mm/year, respectively. The displacement direction is towards the northwest. The strain estimation using the kriging method combined with the gaussian sequential simulation technique obtained an average strain value of 0.05 microstrain/year. The result of the data processing at each station has different arrow lengths, meaning that each location has a different strain value.

Instrument Response Removal and the 2020 MLg 3.1 Marlboro, New Jersey, Earthquake

To better understand earthquakes as a hazard and to better understand the interior structure of the Earth, we often want to measure the physical displacement, velocity, or acceleration at locations on the Earth’s surface. To this end, a routine step in an observational seismology workflow is the removal of the instrument response, required to convert the digital counts recorded by a seismometer to physical displacement, velocity, or acceleration. The conceptual framework, which we briefly review for students and researchers of seismology, is that of the seismometer as a linear time-invariant system, which records a convolution of ground motion via a transfer function that gain scales and phase shifts the incoming signal. In practice, numerous software packages are widely used to undo this convolution via deconvolution of the instrument’s transfer function. Here, to allow the reader to understand this process, we start by taking a step back to fully explore the choices made during this routine step and the reasons for making them. In addition, we introduce open-source routines in Python and MATLAB as part of our rflexa package, which identically reproduce the results of the Seismic Analysis Code, a ubiquitous and trusted reference. The entire workflow is illustrated on data recorded by several instruments on Princeton University campus in Princeton, New Jersey, of the 9 September 2020 magnitude 3.1 earthquake in Marlboro, New Jersey.

Reinforced concrete slabs on yielding supports under dynamic load

The paper presents the experimental results of strength and deformability of reinforced concrete slabs on yielding supports arranged along the perimeter under the dynamic loading. Crushable ring-shaped inserts deforming at the elastic, plastic and curing stages are considered as yielding supports. The displacement, velocity and acceleration are evaluated depending on the deformation stage of yielding supports. The high efficiency is shown for the use of yielding supports, which leads to a significant reduction in the structure displacement, strain, and stress.

Aplikasi Jaringan Saraf Tiruan dengan Metode Fungsi Tan-Sigmoid dalam Memprediksi Kinerja Struktur Bangunan Gedung

Gempa bumi merupakan salah satu ancaman terbesar terhadap gedung, sehingga perlu untuk mendesain gedung dengan memperhitungkan pembebanan gempa bumi yang terjadi. Dengan bantuan software finite element dapat diperoleh respons struktur berupa displacement, velocity, dan acceleration yang terjadi akibat gempa bumi. Jaringan Saraf Tiruan (JST) merupakan salah satu metode yang dapat memprediksi kerusakan bangunan dengan memanfaatkan data respons struktur dengan waktu analisis yang relatif lebih singkat dibandingkan menganalisis struktur satu per satu. Penelitian ini bertujuan untuk menganalisis data gempa dengan magnitude intensitas tinggi yang berbeda-beda. Data input dan output diperoleh melalui software Finite Element untuk menghasilkan jumlah data yang diperlukan JST yaitu sebanyak 4489 data. Pada penelitian ini, komposisi yang digunakan untuk training, testing, dan validating adalah 60%, 25%, dan 15% masing – masingnya. Data input yang digunakan yaitu waktu, acceleration arah x dan y, velocity arah x dan y, serta displacement arah x dan y. Sedangkan untuk data target yang digunakan yaitu kinerja struktur yang ditentukan oleh FEMA 356 dan simpangan antar lantai arah x dan y. Hasil pengujian menunjukkan analisis oleh JST yang menggunakan transfer function Tan-Sigmoid menunjukkan nilai R2 sebesar 97,542% dan Mean Square Error (MSE) yang dihasilkan yaitu sebesar 1,2449.E-07. Hal ini menunjukkan analisis JST dengan transfer function Tan-Sigmoid dapat digunakan untuk memprediksi kinerja dari struktur dengan cepat dan akurat. Dengan demikian metode ini diharapkan dapat direkomendasikan untuk Structural Engineer dan perencana gedung dalam mendesain bangunan gedung bertingkat tahan gempa.

Development of the surface displacement velocity in a full-scale loamy model slope under multistep excavation

Multistep excavations were implemented at the toe of a large-scale slope model, and the surface displacements in the slope were measured to examine the validity of the relationship between the velocity and acceleration proposed by Fukuzono for excavated slopes. The surface displacement increased both during and after slope excavation, among which the latter was due to creep deformation under a constant stress. The rate of increase in the surface displacement was initially high and then decreased to zero during creep deformation after the excavation without slope failure. However, the surface displacement exhibited an accelerated increase during creep deformation after the final excavation prior to slope failure; the surface displacement increased with small fluctuations even before slope failure occurred. The surface displacement velocity and acceleration also fluctuated notably due to variations in the surface displacement. The trendlines for the derived relationships between the velocity and acceleration were in good general agreement with the measured data at certain locations in the model slope. These relationships were unique at different locations on the slope, while the inclination of the relationship trendline suddenly decreased just prior to slope failure. The steeper trendlines predicted an earlier failure time if the displacement was large and close to the failure condition, whereas they resulted in worse predictions if the displacement was small and far from causing slope failure according to the prediction method proposed by Fukuzono.

Inelastic response spectra of self-centering structures with the flag-shaped hysteretic response subjected to near-fault pulse-type ground motions

Many studies on the inelastic response spectra have mainly focused on structures with the conventional hysteretic behavior. However, for self-centering structures with the flag-shaped (FS) hysteretic behavior, the corresponding study is limited. The primary aim of this study is to investigate the inelastic response spectra of self-centering structures with FS hysteretic behavior subjected to the near-fault pulse-type ground motion. To this end, the smooth FS hysteretic model based on Bouc–Wen model is developed, and the characteristics of pulse-type ground motions are described in detail. It is found that the general features of inelastic response spectra of the FS model are sensitive to the acceleration-, velocity-, and displacement-sensitive spectral regions of the ground motion. The inelastic displacement, velocity, acceleration, and ductility factor spectra of the FS hysteretic model for pulse-type ground motions are much larger than those for ordinary ground motions, while the residual displacement spectra under the two types of ground motions are both very small due to its self-centering capacity. Moreover, the inelastic response spectra are affected by the ground motion characteristics and structural hysteresis behavior, especially the large pulse period and peak ground velocity (PGV) significantly increase the inelastic displacement, velocity, and acceleration spectra.

Fracture of Electron Beam Welding Joints of Titan Alloys

Analysis of fracture surfaces morphology of material of welded joints of Ti-TiB system alloys and (α + β) Тi alloy, obtained by electron-beam welding under various technological modes, is carried out. Parameters alterable were the electron beam displacement velocity and initial temperature of the parts welded. Prevalent effect of boron phase on fracture character of Ti-TiB system alloys and possibility of ductility increase both Ti-TiB system and (α+β Тi alloy, due to thermal effect action, is shown.

Contact Stress Distribution of a Pear Cam Profile with Roller Follower Mechanism

The problem of this paper is the high contact stress at the point of contact between the cam and the follower. A pear cam and roller follower mechanism were studied and analyzed for different position of the follower and different contact compression load. The objective of this paper is to study the effect of contact compression load on the contact stress distribution of the cam profile at the point of contact. Four different positions of the follower with the cam was considered (0°, 90°, 180°, and 270°). The theory of circular plate was applied to derive the analytic solution of the contact stress. The numerical simulation had been done using ANSYS Ver. 19.2 package to determine the contact stress, while SolidWorks software was used to investigate follower displacement, velocity, and acceleration. Four distinct values of the compression contact load, such as 3.121 N, 6.242 N, 9.364 N, and 12.485 N, were used in the numerical simulation. In the experiment setup, a photo-elastic technique was carried out in the field of polarized light to exhibit the stress distribution on the cam specimen. The annealed PSM-4 backalate material was used in the experiment setup. The experimental value of contact stress was checked and verified analytically and numerically at the point of contact. The innovation in this paper the use of spring-damper system which reduce the value of contact stress at the point of contact. The contact stress was maximum 2.136 MPa when the follower located at 270° with the cam, while the contact stress was minimum 1.802 MPa when the follower located at 180° at compression load 12.485 N.

A model for interpreting the deformation mechanism of reservoir landslides in the Three Gorges Reservoir area, China

Landslides whose slide surface is gentle near the toe and relatively steep in the middle and rear part are common in the Three Gorges Reservoir area, China. The mass that overlies the steep part of the slide surface is termed the “driving section”, and that which overlies the gentle part of the slide surface is termed the “resisting section”. A driving–resisting model is presented to elucidate the deformation mechanism of reservoir landslides of this type, as exemplified by Shuping landslide. More than 13 years of field observations that include rainfall, reservoir level, and deformation show that the displacement velocity of Shuping landslide depends strongly on the reservoir level but only slightly on rainfall. Seepage modeling shows that the landslide was destabilized shortly after the reservoir was first impounded to 135 m, which initiated a period of steady deformation from 2003 to 2006 that was driven by buoyancy forces on the resisting section. Cyclical water level fluctuations in subsequent years also affected slope stability, with annual “jumps” in displacement coinciding with drawdown periods that produce outward seepage forces. In contrast, the inward seepage force that results from rising reservoir levels stabilizes the slope, as indicated by decreased displacement velocity. Corrective transfer of earth mass from the driving section to the resisting section successfully reduced the deformation of Shuping landslide and is a feasible treatment for huge reservoir landslides in similar geological settings.