Stone Mass Research Articles

Flexible and navigable suction access sheaths: what size stone particles can be cleared?

To perform benchtop experiments on flexible and navigable suction (FANS) ureteric access sheaths (UASs) to determine the clearance capabilities for various stone sizes when paired with different-sized ureteroscopes. Quartz stones were used as a surrogate for renal stones. Stone samples were created to simulate the range of particle sizes produced by 'dusting' a 1-cm calcium oxalate monohydrate stone. The stone mixture was introduced into an open vial at a 30° angle in aliquots every 3 min over the course of 30 min, mimicking their gradual production by lasertripsy. This benchtop model focused on the effects of geometry (between FANS access sheath and ureteroscope) and suction, excluding complex fluid flow. An 11/13-F ClearPetra® FANS UAS with an indwelling ureteroscope was free to move in the vial and targeted visible stones. The vial was intermittently filled to 40 mL with water and emptied using 200-mmHg suction. The experiment had two arms: (1) a permanently indwelling ureteroscope in the FANS UAS to mimic continuous lasering with aspiration and (2) intermittent withdrawal of the ureteroscope to mimic pausing lasering to clear larger fragments through the empty FANS sheath lumen. Three ureteroscope sizes were used: 9.5-F (Lithovue™), 7.5 F (PUSEN) and 6.3 F (Hugemed). The experiment was performed three times for each ureteroscope. With a permanently indwelling 9.5-F ureteroscope, the FANS UAS cleared 64% of the overall stone mass but became blocked after an average of 21 min. Intermittent withdrawal of the ureteroscope cleared all stones. With indwelling 7.5-F and 6.3-F ureteroscopes, the FANS UAS did not become blocked and completely cleared stones of up to 500 μm and 2 mm, respectively. Without withdrawing the ureteroscope (potentially allowing continuous lasertripsy), it is possible to continuously aspirate small fragments alongside a 7.5-F and a 6.3-F ureteroscope in an 11/13-F FANS UAS. Intermittent withdrawal of either of the ureteroscope from the FANS UAS allows complete stone clearance.

Stones in the lower pole and their treatment

The most frequent initial clinical symptom is flank pain, which occurs in approximately half of affected patients with stones of the upper urinary tract. Of these patients approximately half require treatment and 50% will again have new stones in the future. Only 8% of urinary stones are clinically inapparent with 25-50% of the stones located in the lower calyx group and are incidentally discovered during the diagnostics of symptomatic stones. Stones in the lower calyx are more difficult to treat than other kidney stones due to the localization and the resulting access possibilities. The treatment must therefore be planned and carried out individually according to the available treatment options. Since the development of modern flexible ureterorenoscopes (URS) retrograde stone removal, which has few complications, has been highly valued in the treatment of stones of the lower calyx due to the desired primary stone clearance rates. Limiting factors are the longer treatment times for large stone masses and the considerable material costs. Furthermore, the various forms of percutaneous nephrolitholapaxy provide additional methods for the treatment of larger lower caliceal stones.

Optimizing Fragmentation while Minimizing Thermal Injury Risk with the Thulium Fiber Laser in Ureteral Stone Lithotripsy: An In Vitro Study.

Objective: To optimize thulium fiber laser (TFL) settings for effective stone fragmentation although minimizing thermal injury in confined ureteral spaces using a three-dimensional ureter model. Materials and Methods: A hydrogel-based ureter model was maintained at 37.2 ± 0.5°C, with a cylindrical BegoStone (10 × 10 mm, 1.00 ± 0.07 gm) occluding the ureter. Ureteroscopy was performed using a 150 µm TFL fiber for 3 minutes with room temperature irrigation and differing rates (0, 20, 40 mL/min) and power settings (6.4 to 20 W). Maximum sustained temperature (MST) and cumulative thermal dose (cumulative equivalent minutes at 43°C) were assessed against a 120-minute safety threshold. We also evaluated the effects of ureter volume and irrigation temperature. Stone mass treated was calculated by subtracting the mass of residual fragments >3 mm from the initial mass. Results: At 6.4 and 10 W, MSTs were below body temperature, and thermal doses were under 1 minute, indicating minimal thermal risk. At 20 W with 20 mL/min irrigation, MST exceeded 43°C within seconds, and thermal doses surpassed 120 minutes. Treatment efficiency was highest at 20 W (1.58 mg/s), followed by 10 W (1.15 mg/s) and 6.4 W (0.78 mg/s). Among 10 W settings, 1.0 J/10 Hz was more efficient than 2.0 J/5 Hz and 3.0 J/3 Hz. Safe settings produced 95.5% fine dust, whereas high-energy pulses 2-3 J produced significantly more fragments (1-3 mm) compared with settings with pulse energy 0.5-1.0 J. Increasing irrigation to 40 mL/min or using 15°C irrigation effectively reduced MST and improved efficiency, particularly at 20 W. Conclusion: Our study demonstrates the risk of thermal injury with 20 W TFL treatment. Conversely, 10 W settings at 2.0 J/5 Hz are safe and effective for fragmentation. Future research will focus on validating these optimal settings for human stone treatment.

Assessment of a novel bendable-tip ureteral access sheath with integrated suction: an in vitro study.

Surgical management of urinary stones has significantly evolved with the advent of extracorporeal shockwave lithotripsy, flexible ureterorenoscopy (fURS), and percutaneous nephrolithotomy. For lower pole stones larger than 1cm, the choice between fURS and miniaturized percutaneous nephrolithotomy remains debated. fURS with ureteric access sheaths (UAS) is a widely utilized technique, but fragment clearance is challenging in unfavorable anatomical conditions and/or lower pole stones. This study compares a novel flexible suction UAS (FANS) with a standard UAS in an in vitro model of lower pole stones.An in vitro experiment was conducted using an anatomical model of the urinary tract with artificial stones simulating complex 1-cm lower pole stones. Fourteen procedures were performed using either a 12/14 Fr diameter standard UAS or FANS. Every experiment was performed by a single surgeon using a 8.4 Fr single-use digital flexible ureteroscope and holmium:YAG laser set at 0.5J, 25Hz, and short pulse with a 272μm fiber. Operative times, stone clearance rates, lasering times, were recorded and the residual stone masses (> 2mm) was quantified.Complete stone clearance was achieved in 5 out of 7 procedures using FANS while no complete stone clearance was achieved using the standard UAS. The median laser time [27:33 (26:06-28:24) vs 24:02 (21:25-25:04) mm:ss, p = 0.017] and total energy output energy [20663 (19,575-21,325) vs 18,270 (16,069-18,931) J, p = 0.017] were significantly lower in the FANS group (p = 0.017), and the operative time was comparable.This in vitro experiment suggests that fURS with novel FANS may improve stone clearance and improve laser efficiency when compared to the standard UAS, without increasing operative times. Further clinical trials are warranted to confirm these findings.

Effect of Polypropylene and Straw Fiber Materials on the Unconfined Compressive Strength of Tailings and Wasted Stone Mixed Backfill.

Ensuring the mechanical performance of backfill materials while reducing cementation costs is a key challenge in mine backfill research. To address this, fiber materials such as polypropylene (PP) fiber and rice straw (RS) fiber have been incorporated into cement-based mixtures for mine backfilling. This study investigates the effects of PP and RS fibers on the mechanical properties, flow characteristics, and microstructure of Tailings and Wasted Stone Mixed Backfill (TWSMB). A series of orthogonal experiments were designed to evaluate the influence of variables, including the cement-sand ratio, solid mass concentration, wasted stone mass concentration, fiber content, and fiber length on the TWSMB properties. The results indicate that the influence of cement-sand ratio and solid mass concentration have a more significant impact on strength than fibers, though the fibers show a stronger effect than the wasted stone mass concentration. Both fiber types enhanced the strength of the specimens, with PP fiber exhibiting a stronger reinforcing effect than RS fiber. Furthermore, the effect of PP fiber content was more pronounced than that of fiber length, whereas the opposite trend was observed for RS fiber. The optimum fiber parameter levels were determined for each type: PP fiber performed best at a mass concentration of 1.5% and a length of 6 mm, while RS fiber showed optimal performance at a mass concentration of 1.0% and a length of 5-10 mm. Macroscopic damage analysis indicated that the structural integrity and residual compressive strength of the TWSMB specimens were preserved even after surpassing the ultimate compressive strength, due to the crack-bridging effect of the fibers. Microstructural analysis showed that PP fiber-reinforced specimens exhibited a dense structure formed through reactions with other hydration products. In contrast, the surface of RS fibers was nearly fully encapsulated by hydration products, resulting in the formation of a physical skeleton structure. This study provides new insights into minimizing cement consumption and reducing backfilling costs in mining operations.

Initial experience with augmented reality in planning renal access for PCNL

Achieving renal access during percutaneous nephrolithotomy is challenging, with a complication rate of 10–20%. This study aims to assess a novel technique for planning access to the renal collecting system using augmented reality (AR). Using Digital Imaging and Communications in Medicine software (DICOM 2-print), we generated 3-dimensional (3D) models of patients with different types of kidney stones (staghorn, lower pole, and pelvic stones) who underwent PCNL between 2018 and 2022. After viewing the patient’s CT scans, surgeons explored the anatomical models using an AR system with a stereoscopic 3D lens array display. Using questionnaires, we quantitatively estimated the model’s contribution on a scale of “1” (“poor”) to “5” (“excellent”) to the surgeon’s understanding of stone location, patient anatomy, and ease of access compared to 2D CT imaging. A total of 38 questionnaires were completed by 13 urologists. Estimating renal location, renal pelvis, and stone mass were better demonstrated by AR (5 vs. 4, p < 0.001). The orientation of adjacent organs was better understood using AR (5 vs. 4, p = 0.004). In 86.8% of cases, surgeons preferred using AR models both before and during surgery, with 69.2% suggesting that AR could enhance procedural safety. The time frames for testing the models differed between senior and junior practitioners (p = 0.016) and were significantly reduced with model experience (p < 0.001). When comparing CT to 3D imaging, AR models provide a better understating of stone location, patient anatomy, and route of access to the collecting system. Further research is required to implement this innovative technique preoperatively and intra-operatively.

Enhanced horizontal deposition of large stone in granular flow with mixing small spherical grains after slide along slope and free fall

Geophysical mass flows, which could endanger our health, lives, and property safety, commonly occur in mountain regions. Although many efforts have been made, transport of granular flows consisting of polydisperse grains, which is influenced by multiple factors, is still not well understood. This work focused on the effect of small spherical grains on the movement of large stones in granular flows of different grain compositions (quartz gravel, glass bead and angular stone), through experimentally measuring mass frequency distributions of granular materials deposited on flat surface. Three characteristic deposition distances (X20, X50 and X80) and one extreme mobility probability (Ps) were extracted from cumulative frequency distributions. It reveals that, in most of cases, the inclusion of glass beads reduced X20, X50, and X80 but increased Ps for total mass. For angular stone mass, the inclusion of glass beads increased the occurrence frequency of that X20, X50 and X80 increase, apart from increasing Ps. These results indicated small spherical grains could effectively enhance the extreme mobility of large angular stones in mixtures. We hope these results could be helpful for improving our understanding of the transport of geophysical mass flow as well as the grain segregation in different natural environment.

Distribution and habitat preference of Agama bibronii (Duméril, 1851) in Tissemsilt province, Algeria

The aim of this study is to investigate the spatio-temporal distribution and ethological analysis of the Agama bibronii in Tissemsilt province. This area of north-west Algeria is characterised by a rugged orography, dominated by rock formations, and these stone masses shelter a remarkable wealth of fauna and flora, including the A. bibronii that is the focus of our study. Field surveys carried out at monthly intervals between 2018 and 2021 in 16 different localities allowed us to observe 41 individuals (including 22 males and 19 females). This study revealed a concentration of A. bibronii populations in the southern part of Tissemsilt, particularly in bare rocky habitats, where the locality of Sidi Bentamra is the most marked, hosting the largest number of individuals. These results contribute to our understanding of the species’ distribution and habitat preferences in the region. The individuals identified at the end of this study will be the subject of an ethological study to better understand the biology and ecology of this reptile.

Urinary stone ablation with a thulium fibre laser: a rate-of-completion evaluation

Introduction. The main disadvantage of using the rate of ablation of urinary stones as a parameter of thulium lithotripsy is the dependence of this parameter on the energy and frequency of laser pulses. Therefore, the results of measurements of this parameter by researchers differ significantly, since they were carried out at different values of the energy and pulse frequency, as well as at different values of the radiographic density of stones.Objective. To develop a universal indicator to assess the specific value of reducing the mass of urinary stones when performing laser lithotripsy.Materials &amp; methods. We have analyzed scientific publications in domestic and foreign specialized publications (2005 to 2023) related to the measurement of urinary stone ablation rate during thulium laser lithotripsy. We used physical methods of estimation of specific values when we developed a universal indicator of specific value of stone mass reduction.Results. Having processed the data, we obtained the average value of the specific indicator of urinary stone mass reduction per unit of pulse energy during thulium lithotripsy in the ‘dusting mode’, equal to 0.059 ± 0.003 mg/J. The article provides a formula for calculating the "pure" time of lithotripsy, as well as examples of calculating the specific indicator of the stone mass reduction and the time of lithotripsy.Conclusion. This value can be used both to evaluate the efficiency of thulium laser lithotripsy and to predict the time of lithotripsy.

Exploring optimal settings for safe and effective thulium fibre laser lithotripsy in a kidney model.

To explore the optimal laser settings and treatment strategies for thulium fibre laser (TFL) lithotripsy, namely, those with the highest treatment efficiency, lowest thermal injury risk, and shortest procedure time. An in vitro kidney model was used to assess the efficacy of TFL lithotripsy in the upper calyx. Stone ablation experiments were performed on BegoStone phantoms at different combinations of pulse energy (EP ) and frequency (F) to determine the optimal settings. Temperature changes and thermal injury risks were monitored using embedded thermocouples. Experiments were also performed on calcium oxalate monohydrate (COM) stones to validate the optimal settings. High EP /low F settings demonstrated superior treatment efficiency compared to low EP /high F settings using the same power. Specifically, 0.8 J/12 Hz was the optimal setting, resulting in a twofold increase in treatment efficiency, a 39% reduction in energy expenditure per unit of ablated stone mass, a 35% reduction in residual fragments, and a 36% reduction in total procedure time compared to the 0.2 J/50 Hz setting for COM stones. Thermal injury risk assessment indicated that 10 W power settings with high EP /low F combinations remained below the threshold for tissue injury, while higher power settings (>10 W) consistently exceeded the safety threshold. Our findings suggest that high EP /low F settings, such as 0.8 J/12 Hz, are optimal for TFL lithotripsy in the treatment of COM stones. These settings demonstrated significantly improved treatment efficiency with reduced residual fragments compared to conventional settings while keeping the thermal dose below the injury threshold. This study highlights the importance of using the high EP /low F combination with low power settings, which maximizes treatment efficiency and minimizes potential thermal injury. Further studies are warranted to determine the optimal settings for TFL for treating kidney stones with different compositions.

An experimental investigation to optimise pebbles-based sensible heat storage system: An exploration to improve thermal efficiency of solar devices

An experimental investigation to optimise pebbles-based sensible heat storage system: An exploration to improve thermal efficiency of solar devices

Development of a burst wave lithotripsy system for noninvasive fragmentation of ureteroliths in pet cats

BackgroundUpper urinary tract stones are increasingly prevalent in pet cats and are difficult to manage. Surgical procedures to address obstructing ureteroliths have short- and long-term complications, and medical therapies (e.g., fluid diuresis and smooth muscle relaxants) are infrequently effective. Burst wave lithotripsy is a non-invasive, ultrasound-guided, handheld focused ultrasound technology to disintegrate urinary stones, which is now undergoing human clinical trials in awake unanesthetized subjects.ResultsIn this study, we designed and performed in vitro testing of a modified burst wave lithotripsy system to noninvasively fragment stones in cats. The design accounted for differences in anatomic scale, acoustic window, skin-to-stone depth, and stone size. Prototypes were fabricated and tested in a benchtop model using 35 natural calcium oxalate monohydrate stones from cats. In an initial experiment, burst wave lithotripsy was performed using peak ultrasound pressures of 7.3 (n = 10), 8.0 (n = 5), or 8.9 MPa (n = 10) for up to 30 min. Fourteen of 25 stones fragmented to < 1 mm within the 30 min. In a second experiment, burst wave lithotripsy was performed using a second transducer and peak ultrasound pressure of 8.0 MPa (n = 10) for up to 50 min. In the second experiment, 9 of 10 stones fragmented to < 1 mm within the 50 min. Across both experiments, an average of 73–97% of stone mass could be reduced to fragments < 1 mm. A third experiment found negligible injury with in vivo exposure of kidneys and ureters in a porcine animal model.ConclusionsThese data support further evaluation of burst wave lithotripsy as a noninvasive intervention for obstructing ureteroliths in cats.

Assessing indoor thermal comfort of rock-cut architecture in Meymand world heritage site during winter and summer

Rock-cut architecture is among the unique types of ancient architecture in Iran, which creates human living space by excavating the stone mass in the rocks. The rock-cut architecture benefits from utilization of the temperature of the groundmass in cold and hot weather by penetrating its heart. The World Heritage Site of rock-cut architecture in Meymand with more than 360 architectural units is considered as an evolved and appropriate example of such architecture in the semi-hot and dry foothill climate of Iran. The present study aims to determine indoor thermal comfort level of some buildings in the site as mentioned earlier to measure their fitness to climatic conditions of the area without energy consumption. To this aim, Predicted Mean Vote (PMV) index was determined for four selected buildings through the indoor bioclimatic monitoring, as well as calculating the level of the above-mentioned index during December–February and June–August.​ Then, the ASHRAE standard questionnaire was prepared to evaluate and compare the comfort sensation feedback of the occupants in the aforementioned buildings with indoor PMV calculation results. The results indicated that the average indoor PMV during the winter and summer equaled -2.17 and -1.07 with a cold and cool sensation, respectively, which is in line with those of the questionnaire in which most occupants reported a neutral and cold sensation during the winter and a cool one during the summer. In addition, calculation of the percentage of proximity to the comfort zone for indoor environment of the above-mentioned buildings showed they are closer to comfort by 22% and 36%, during the winter and summer, respectively Finally, the results indicated the rock-cut architectural buildings had provided conditions by applying the high thickness of their architectural layers, low heat exchange coefficient of the walls, and temperature of the groundmass, which they are in the comfort zone without energy consumption in summer and provide living conditions with minimal energy consumption in winter.

Enhanced popcorning using polyanionic chelating solutions as irrigation.

Poly-anionic compounds can chelate divalent cations and dissolve calcium oxalate stone. Our objective was to assess how much concurrent irrigation with poly-anionic chelating solutions during non-contact laser lithotripsy or popcorning could improve stone ablation rate. A popcorning model was created by lowering a ureteroscope with thulium fiber laser into a test tube calyx. Begostones of matching size and mass were placed in the test tube and treated with the laser while irrigating with different iso-osmolar poly-anionic solutions. We compared 0.9% sodium chloride (NaCl), sodium citrate, sodium hexa-metaphosphate, and sodium ethylenediaminetetraacetate (EDTA) solutions. After treatment, residual stones were passed through a 1mm sieve, and remaining fragments greater than 1mm were weighed as remaining stone mass. Average remaining stone mass after lithotripsy with NaCl irrigation was 27.8% (± 10.0%). The average remaining stone mass after lithotripsy with hexa-metaphosphate, sodium citrate, and EDTA irrigation was 28.9% (± 13.4%), 17.5% (± 10.5%), and 9.8% (± 5.7%) respectively. Compared with NaCl, there was a 37% reduction in remaining stone mass when using citrate (p = 0.008) and a 64.7% reduction when using EDTA irrigation during lithotripsy (p < 0.001). Concurrent irrigation with citrate or EDTA solutions synergistically enhances the efficacy laser lithotripsy in this in vitro popcorning model. This may lead to tangible improvements in endoscopic stone removal outcomes; however, the effectiveness on different stone types and safety during short duration lithotripsy should be further investigated.

MP05-14 ENHANCED POPCORNING USING POLYANIONIC SOLUTIONS AS IRRIGATION

MP05-14 ENHANCED POPCORNING USING POLYANIONIC SOLUTIONS AS IRRIGATION

PD28-04 ADVANCED BURST WAVE LITHOTRIPSY FOR HUMAN TRIALS

PD28-04 ADVANCED BURST WAVE LITHOTRIPSY FOR HUMAN TRIALS

Клінічне значення ідентифікації сечових каменів пацієнтів, мешканців промислового регіону методом Mid-FTIR Spectroscopy

Introduction. Physico-chemical, biological and biochemical processes that occur during the formation of urinary stones determine the peculiarities of their composition and structure, as evidenced by modern methods of analysis: spectral, X-ray, polarization, optical, immersion, infrared spectrometry, etc. Modern Fourier Transform Infrared (FTIR) spectroscopy is a powerful instrument for identifying organic and inorganic substances by measuring the infrared (IR) absorption spectrum. It provides qualitative information about the molecular composition of the target material. The aim of the study. To determine the possibilities and improve the results of identification of urinary stones of patients, residents of the industrial region by the method of Mid-FTIR Spectroscopy. Materials and methods. To carry out the work, a comparative analysis of the chemical composition, morphology and structural features of 85 urinary stones of patients, residents of the Dnipropetrovsk region, was carried out. The analysis of the mineral composition of all urinary stones was carried out by a hardware and software complex that combined a Nicolet iS10 FTIR spectrometer and μ-FTIR Continuum microscope from the American company Thermo Scientific, ATR-Smart Golden Gate prefix with a diamond crystal from the English company Specac, OMNIC FTIR Software and Spectral Library NICODOM IR Kidney Stones, which contains 1668 transmission spectra. Research results and their discussion. Most of the stones in 48% of patients were oxalates, 43% of the stones belonged to the oxalatecontaining mixed type. Conditionally pure urate and phosphate stones were 4% and 5%, respectively. The registered spectra generally showed a satisfactory agreement with the library analogues. The capabilities of the hardware and software complex make it possible to map and visualize the spatial distribution of organic substances and minerals in rock samples. The μ-FTIR method makes it possible to reasonably understand the cause of the microstructural heterogeneity of stones and the triggering mechanism of the layer-by-layer deposition of constituent substances during the growth of the stone mass. Conclusion. The analysis of the results of the identification of urinary stones of patients, residents of the industrial region by the Mid- FTIR Spectroscopy method showed advantages among similar methods of studying urinary stones and proved the feasibility of its use in the complex examination of patients with urolithiasis. Accurate analysis of the primary and secondary chemical composition and spatial distribution of stone components will lead to an understanding of the physicochemical processes that form the basis of the pathogenesis of stone formation. Spectral monitoring of the chemical composition of urine is important for early diagnosis, effective personalized treatment and prevention of stone recurrence in patients with urolithiasis.

Inferred costs and functional consequences of stone morphometry in the stone‐carrying displays of Black Wheatear (Oenanthe leucura)

Post‐mating courtship displays are often viewed as forms of sexual selection that allow individuals to assess fitness benefits from their mates based on honest signalling. However, display costs are not always easy to identify and quantify. Before each breeding attempt, male Black Wheatears Oenanthe leucura carry tens of heavy stones with the bill to form piles near the nest. The consequent increase of wing loading is considered the key display cost, and stone mass a key signal of male quality. However, males must also cope with neck and bill torques, and with outward‐pushing forces that tend to slip stones out of the bill; these effects partly depend on stone morphometry. I evaluated the effects of stone morphometry by comparing stones from two territory types differing in density (thus volume for a given mass), i.e. abandoned houses (less dense) versus rock outcrops (more dense). The comparison included samples of available stones to collect (ground), and stones actually collected by the birds (display). Regardless of territory type, display stones were significantly thinner, and generated higher estimated torques but lower outward‐pushing forces, than ground stones of the same mass. On average, display stones were also thicker in abandoned houses than in rock outcrops, but their mass was also significantly lower, which resulted in transport costs being similar between territory types. This suggests that males randomly select the stones that they can handle within the limits of local availability and, in abandoned houses, they have more difficulties in handling the heaviest transportable stones because many of these have too great a volume. This study calls for further experimental research on male performance and the cues that females use to assess the display. A broader conceptual framework is also necessary to address the behavioural and morphological consequences of carrying rigid objects with the bill.

Development of an automated laser drilling algorithm to compare stone ablation patterns from different laser pulse modes.

To develop a novel automated three-dimensional (3D) laser drilling algorithm to further investigate laser-stone interaction with different laser pulse modes. Comparison of post-ablative lattice architecture combined with mass of stone ablated can provide a more complete understanding of differences between pulse mode. A 3D positioner (securing laser fiber) was programmed to create a 5 × 5 grid of drill holes spaced 1mm apart on 15:5 cylindrical BegoStones. Beginning 0.5mm above the stone surface, the laser fiber was activated and advanced 2mm toward and into the stone for all 25 points. Four trials for each pulse mode [short pulse (SP), long pulse (LP), Moses Contact (MC), Moses Distance (MD)] were completed. Outcome measures were assessment of lattice preservation and mass of ablated stone. MC exhibited the greatest lattice preservation and least stone mass ablated (50.5 ± 2.2mg). SP (69.4 ± 4.3mg) and MD (70.0 ± 2.6mg) had the greatest lattice destruction and stone mass ablated. The differences in stone ablated between MC and MD (p = 0.00003), MC and SP (p = 0.0002), and LP and MD (p = 0.004) were statistically significant. Consistent quantitative and qualitative differences between pulse modes were observed with a novel automated 3D laser drilling algorithm applied to BegoStone. The laser drilling algorithm developed here can be used to further enhance mechanistic understanding of laser-stone interactions and facilitate selection of appropriate laser pulse modes to balance precision and efficiency across the range of laser lithotripsy techniques.

Dynamic responses of 500-kV transmission line towers under impact force of rockfall in a mountainous area

Since most of the UHV/EHV transmission lines pass through mountainous areas, the impact of rocks caused by landslides or collapses may cause partial deformation of the iron tower, or even collapse, seriously threatening the safety operation of transmission lines. To analyze the dynamic response characteristics and influencing factors of the rolling rock impacting the transmission line tower, a simulation model for the 500-kV steel suspension tower impacted by the falling rock was established by finite element analysis software LS-DYNA in this study, and dynamic response characteristics of the rolling rock impacting the steel tower were analyzed under different conditions. Results show that the stress on the tower foundation is closely related to the mass, volume, and initial velocity of the rolling stone. Under the same rolling stone speed, the stress on the tower foundation increases as the mass of the rolling stone increases. The maximum increase in peak stress generated between the two can reach 110%; when rolling stones of the same size collide with different initial velocities, the location and magnitude of the peak stress of the tower foundation are different. When the initial speed of the rolling stones is more remarkable than 15 m/s, the tower foundation of the hit area increased significantly, causing the tower base to be directly destroyed.