Thermal Spread Research Articles

Effect of sidewall spacing on the temperature field of a three-dimensional heated turbulent wall jet

The effect of sidewalls on the temperature field of a three-dimensional heated turbulent wall jet is characterized by the temperature measurement inside the sidewall enclosure (SWE). The SWE is defined as the presence of sidewalls parallel to the vertical jet centerline plane on both the sides. The sidewalls are equally spaced from the vertical jet centerline plane, and the distance between the sidewall is termed as the width (W). Four different widths (W) 140 mm, 160 mm, 180 mm, and 200 mm SWE are considered at a Reynolds number of Re= 25,000. The temperature field decay rate is increased with an increase in the SWE width in the downstream locations after x/h= 35. The decay rate of the jet centerline temperature in 200 mm SWE is 4.6% higher than the 140 mm SWE. The lateral spread increases with a decrease in SWE width due to the accumulation of the thermal energy content in the lateral shear layers adjacent to the sidewalls. In the near field, thermal spread in the wall-normal direction increases with the increase in the SWE width, but in far-field locations (x/h= 30), the thermal spread increases with a decrease in the SWE width. The wall-normal thermal similarity is delayed with a decrease in the width of the SWE, and it is found at x/h= 25, 22, 19 and 15 for the 140 mm, 160 mm, 180 mm, and 200 mm SWEs, respectively. The temperature field shows the climbing effect over the sidewalls similar to the velocity field in the transverse plane (z−y). The spread of the temperature fields in the lateral direction increases with the increase in the width of the enclosure. The similarity of the temperature field gets distorted near the sidewall (λ=0.9, where λ=z/(W/2) and z= lateral location) due to thermal energy content in lateral shear layers. The one point temperature fluctuation shows the normal distribution of the probability density function along the jet centerline for all the cases of SWE. The probability density function is independent of the SWE width before the attachment (x/h≤ 10) of the flow stream at the sidewall, but after the attachment (x/h≥ 10) of the flow stream to the sidewalls, the probability density function deviated from the normal distribution curve. The skewness and flatness factors were also calculated based on the instantaneous temperature fluctuation inside the SWE.

Experimental study on the alleviation of thermal runaway propagation from an overcharged lithium-ion battery module using different thermal insulation layers

An efficient and safe thermal insulation structure design is critical in battery thermal management systems to prevent thermal runaway propagation. In this paper, using a common real-life overcharge as a trigger for battery runaway, we investigate the runaway response of the battery module without thermal insulation and with various thermal insulation materials. The experimental results indicate that the thermal insulation has the effect of stopping the thermal spread of the battery module and reducing the maximum temperature. By comparing the temperature change of the batteries, it is discovered that the fiber-based material has a temperature drop efficiency of 71.83%, while the aerogel materials are at least 13% more efficient in temperature reduction than fibrous materials. Meanwhile, it is demonstrated that by examining the capacity characteristics of the damaged battery and the characteristics of the insulation material, the pre-oxidized silk aerogel has the best thermal spread suppression effect and the TG (thermogravimetric) variation withstood high temperatures of up to 746 °C. SEM (scanning electron microscope) morphology for different insulation materials before and after combustion show that pre-oxidized silk aerogel maintains a strong thermal insulation capacity in the thermal spreading. It is expected to have a guidance for the design of thermal insulation in lithium-ion battery modules.

Fertility Sparing Procedure using Carbon Dioxide Fiber Laser Vaporization of Ovarian Endometrioma.

The surgical management of endometrioma is still a matter of debate. Cystectomy, which is recognized as the standard technique, seems to be associated with a potential reduction in the ovarian reserve due to the inadvertent removal and thermal damage of healthy ovarian tissue. New ablative techniques with reduced tissue penetration depth and less thermal spread to the surrounding parenchyma may represent a viable alternative to cystectomy. For these reasons, the aim of this manuscript is to demonstrate the ablation of the endometrioma capsule using a CO2 fiber laser technique and discuss the clinical outcomes. Once the cyst has been drained and washed, a biopsy is taken. After cyst eversion, vaporization of the inner surface of the cyst is performed using a CO2 fiber laser. The technique is simple and reproducible as even young surgeons without any surgical experience were more confident in performing laser CO2 vaporization instead of cystectomy. The positive effects of CO2 technology are reported in a randomized controlled trial, where the postoperative changes in the antral follicular count (AFC) and antimullerian hormone (AMH) levels were compared between patients who had their endometrioma excised (cystectomy) and those who had undergone endometrioma vaporization with CO2 laser. The patients treated with CO2 laser showed significantly increased AFC without a reduction in serum AMH levels as compared to the cystectomy group, in which both parameters were significantly reduced. The postoperative pregnancy rate was also assessed, and comparable pregnancy rates were found after both treatments. On the contrary, patients treated with the CO2 fiber laser technique had more favorable in-vitro fertilization (IVF) outcomes compared to cystectomy. In conclusion, the CO2 fiber laser technique may represent a viable alternative to cystectomy in the surgical treatment of endometrioma in terms of ovarian preservation, pregnancy rates, and IVF outcomes. Moreover, it has the advantage of being independent of the surgeon's skills and personal experience.

Use of Laparoscopic and Laparotomic J-Plasma Handpiece in Gynecological Malignancies: Results From A Pilot Study in A Tertiary Care Center

IntroductionThe J-Plasma has recently been introduced into the surgical community with different intrinsic characteristics aimed to further reduce the thermal effect and enhance precision when compared to standard radiofrequency. This study aimed to investigate the role of this new technology in different conditions of gynecological carcinomatosis characterized by the indication for regional peritonectomy and/or ablation, either in laparotomy (LPT) or in laparoscopy (LPS), in the context of a modern personalized approach to the surgical management of gynecological malignancies.Material and MethodsFrom January 2019 to April 2019, 12 patients were selected for this prospective pilot study at the Division of Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome. In this single surgeon experience, the inclusion criteria were: histologically proven advanced ovarian/endometrial cancer, primary or interval debulking surgery, and intraoperative indication for regional peritonectomy. Six patients were treated by LPS (Group 1) and 6 by LPT (Group 2).ResultsIn Group 1 the indication for debulking surgery was in 4 cases an interval debulking surgery and 2 advanced endometrial cancer. All patients in Group 2 underwent primary debulking surgery for advanced ovarian cancer. The whole cohort achieved a complete tumor excision after surgery. The median OT and median EBL were 195 min and 100 ml in Group 1, and 420 min and 500 ml in Group 2. The median hospital stay was 4 days in Group 1 and 13 days in Group 2, respectively. No intra and postoperative complications were registered within 60 days after surgery.ConclusionsJ-Plasma allows to approach delicate maneuvers on viscera, mesentery, and blood vessels with a high degree of safety and precision thanks to its limited vertical and lateral thermal spread, favoring the surgeon to push ever higher the cytoreduction/morbidity tradeoff. The use of J-Plasma in cytoreductive surgery could also increase the range of possible minimally invasive procedures, narrowing the technical distance with the open technique and thus contributing to designing a personalized surgical strategy for each patient in different scenarios of peritoneal carcinomatosis.

Full-scale experimental study on thermal smoke movement characteristics in an indoor pedestrian street

Indoor pedestrian street, a common architecture scheme, brings both convenience and fire risk in the meantime. Full-scale tests were carried out to study thermal smoke movement characteristics, including smoke development, longitudinal temperature distribution in the room, and horizontal temperature distribution in the ring corridor, in an indoor pedestrian street under different mechanical smoke exhaust modes. Results showed that smoke movement characteristics were mainly influenced by the smoke exhaust mode and building structure. Under natural ventilation, thermal smoke spread along the two crossed channels of the room and entered the adjacent ring corridor and atrium. When the smoke exhaust system was activated, the smoke spread was effectively restricted. As the smoke exhaust was enhanced, the heat release rate of the ventilation controlled fire in the room was increased, resulting in the higher smoke temperature. In addition, the smoke temperature rise decreased exponentially with the increasing longitudinal distance from the fire in the room under all smoke exhaust modes. The stronger smoke exhaust and larger building space leaded to the higher decay rate. In the ring corridor, the decrease of smoke temperature rise with the horizontal distance was exponential under natural ventilation but was linear when the smoke exhaust system was activated. • Thermal smoke spread characteristics in indoor pedestrian street investigated. • Room fire scenarios under four mechanical smoke exhaust modes designed. • Smoke development and temperature distribution in room and ring corridor analyzed. • Effect of different mechanical smoke exhaust modes on smoke spread revealed. • Dimensionless exponential and linear smoke temperature decay models established.

Detection of the Lateral Thermal Spread during Bipolar Vessel Sealing in an Ex Vivo Model-Preliminary Results.

Background: As an unwanted side effect, lateral thermal expansion in bipolar tissue sealing may lead to collateral tissue damage. Materials and Methods: Our investigations were carried out on an ex vivo model of porcine carotid arteries. Lateral thermal expansion was measured and a calculated index, based on thermographic recording and histologic examination, was designed to describe the risk of tissue damage. Results: For instrument 1, the mean extent of the critical zone > 50 °C was 2315 ± 509.2 µm above and 1700 ± 331.3 µm below the branches. The width of the necrosis zone was 412.5 ± 79.0 µm above and 426.7 ± 100.7µm below the branches. For instrument 2, the mean extent of the zone > 50 °C was 2032 ± 592.4 µm above and 1182 ± 386.9 µm below the branches. The width of the necrosis zone was 642.6 ± 158.2 µm above and 645.3 ± 111.9 µm below the branches. Our risk index indicated a low risk of damage for instrument 1 and a moderate to high risk for instrument 2. Conclusion: Thermography is a suitable method to estimate lateral heat propagation, and a validated risk index may lead to improved surgical handling.

Characteristics and Mechanism of Fire Spread between Full-Scale Wooden Houses from Internal Fires

In ancient villages, the spread of uninterrupted fires caused great damage to clustered wooden houses. Thus, the spread of fire among wooden houses should be systematically studied to explore its characteristics. Statistical analysis is a feasible way to study the characteristics and underlying mechanisms of fire in full-scale wooden houses. In this study, 4 full-scale wooden buildings were built in an ethnic village in Guizhou Province, and the fire spread test was conducted by igniting a 0.63-MW power wood crib. To investigate the fire spread, the visual characteristics were observed, and the temperatures and heat radiation at special locations were monitored with thermocouples and radiation flowmeters, respectively. The effect of relative slope, heat radiation, and wind direction on fire spread characteristics was established by mathematical statistics, and the measured temperatures were used to verify the statistics’ regularity. The results showed that in wooden houses, fire spread was mainly influenced by the slope, the distance between houses, and wind direction. When the inner wall of a wooden house is protected by a fireproof coating, the thermal radiation spread and fire spread are both slower. The slope and distance had the same influence weight (0.41) on fire spread; however, since they affect the process in different ways, they should be analyzed separately for fire risk evaluation. The findings of this study provide a theoretical foundation for understanding the fire spread process in wooden buildings.

State-space approach to nonlocal thermo-viscoelastic piezoelectric materials with fractional dual-phase lag heat transfer

Purpose The purpose of this study is to develop a comprehensive size-dependent piezoelectric thermo-viscoelastic coupling model that accounts for two fundamentally distinct size-dependent models that govern fractional dual-phase lag heat transfer and viscoelastic deformation, respectively. Design/methodology/approach The fractional calculus has recently been shown to capture precisely the experimental effects of viscoelastic materials. The governing equations are combined into a unified system, from which certain theorems results on linear coupled and generalized theories of thermo-viscoelasticity may be easily established. Laplace transforms and state–space approach will be used to determine the generic solution when any set of boundary conditions exists. The derived formulation is used to two concrete different problems for a piezoelectric rod. The numerical technique for inverting the transfer functions is used to generate observable numerical results. Findings Some analogies of impacts of nonlocal thermal conduction, nonlocal elasticity and DPL parameters as well as fractional order on thermal spreads and thermo-viscoelastic response are illustrated in the figures. Originality/value The results in all figures indicate that the nonlocal thermal and viscoelastic parameters have a considerable influence on all field values. This discovery might help with the design and analysis of thermal-mechanical aspects of nanoscale devices.

Slowdown of interpenetration of two counterpropagating plasma slabs due to collective effects.

The nonlinear evolution of electromagnetic instabilities driven by the interpenetration of two e^{-},e^{+} plasma clouds is explored using ab initio kinetic plasma simulations. We show that the plasma clouds slow down due to both oblique and Weibel generated electromagnetic fields, which deflect the particle trajectories, transferring bulk forward momentum into transverse momentum and thermal velocity spread. This process causes the flow velocity v_{inst} to decrease approximately by a factor of sqrt[1/3] in a time interval Δt_{αB}ω_{p}∼c/(v_{fl}sqrt[α_{B}]), where α_{B} is the magnetic equipartition parameter determined by the nonlinear saturation of the instabilities, v_{fl} is the initial flow speed, and ω_{p} is the plasma frequency. For the α_{B} measured in our simulations, Δt_{αB} is close to 10 times the instability growth time. We show that as long as the plasma slab length L>v_{fl}Δt_{αB}, the plasma flow is expected to slow down by a factor close to sqrt[1/3].

Evaluation of skin tissue effects from treatment with a novel hand-held plasma energy device.

Plasma IQ™, the first FDA-cleared hand-held plasma energy device, is indicated for removal and destruction of skin lesions and coagulation of tissue. Treatment involves use of an electrostatic plasma spark to heat the skin and create discrete microthermal wounds. Microthermal wounds on pre-auricular and upper eyelid skin from two individual subjects were created using multiple treatment parameters to assess the impacts of power, pulse duration and needle electrode type on wound depth, width and thermal spread, and analyzed using histology to characterize treatment effects. Device power had a statistically significant impact on upper eyelid skin microthermal wound depth and width (2-sided t-test p<0.0001 for both) but not on thermal spread (p=0.1171). No meaningful differences in wound width, depth, or thermal spread were observed based on pulse duration or electrode type. All microthermal wounds demonstrated dual zones of tissue injury and extended to the superficial reticular dermis. Treatment with the Plasma IQ™ device creates focal microthermal wounds of reproducible depth and width that are comprised of dual thermal injury zones similar to other plasma energy skin rejuvenation devices. Device power is the most important factor determining microthermal wound depth and width.

Optical Coherence Tomography Feedback System for Infrared Laser Sealing of Blood Vessels.

Infrared (IR) lasers have recently been tested as an alternative to electrosurgical and ultrasonic laparoscopic devices for optical sealing of blood vessels. IR laser technology previously demonstrated faster sealing times, reduced thermal spread, and lower device temperatures during experimental studies. However, current commercial laparoscopic devices incorporate electrical impedance and/or temperature sensors as real-time, closed-loop, feedback to indicate successful blood vessel seals. This preliminary study explores an infrared laser system for sealing and optical coherence tomography (OCT) as a potential feedback system for successful vessel seal verification. A 1470-nm diode laser delivered an incident power of 30 W for an irradiation time of 5 s using an 8 × 2 mm linear beam, for creating strong seals in porcine renal blood vessels under compression. After sealing the blood vessels, OCT was performed on unsealed and sealed vessel regions for comparison. Standard vessel burst pressure (BP) measurements confirmed successful seals after OCT. Integrated reflectance intensity in OCT A-scans decreased by an average of 20 ± 6% in sealed versus native vessels of 2.4 ± 0.4 mm diameter. Vessel BP measured 532 ± 239 mmHg, with all vessels (n = 25) recording a successful BP > 180 mmHg (hypertensive blood pressure). Unsealed vessels demonstrated significantly deeper imaging marked by a continuous decay in reflected intensity, while sealed vessels showed subsurface reflectance intensity peaks, immediately followed by a rapid decay in reflectance intensity. These markers are consistent with increased light scattering and decreased optical penetration depth upon thermal coagulation of tissues. A-line OCT data consistently differentiated between sealed and unsealed blood vessel regions. Future work will involve OCT integration into the laparoscopic device for real-time optical feedback during IR laser sealing.

Novel multifunctional robotically assisted bipolar instrument for simultaneous radiofrequency sealing and transection: preclinical and single-center experience

BackgroundA novel robotic-assisted bipolar radiofrequency (RF) multifunctional vessel seal-and-transection instrument (SynchroSeal, Intuitive Surgical, Inc., Sunnyvale, CA) has been developed. The objective of the current paper is to describe the design of SynchroSeal based on bench studies, assess the safety of SynchroSeal in ex vivo and in vivo porcine studies, and provide early clinical context.MethodsSynchroSeal grasping, energy activation time, and jaw temperature were evaluated with those of the Harmonic Ace+7. Data were analyzed with descriptive statistics, with Mann–Whitney for comparisons and statistical significance p < 0.05. Ex vivo and in vivo animal safety assessments of tissue after SynchroSeal use were evaluated for burst pressure, thermal spread, and acute sealing. Last, a single-center analysis of the technical metrics of SynchroSeal and Vessel Sealer Extend (robotically assisted seal-and-transection instrument) in bariatric cases is provided.ResultsBench studies of SynchroSeal and Harmonic Ace+7 evidenced SynchroSeal’s greater slip resistance force (8.4 ± 1.0 vs. 3.1 ± 0.4 N; p = 0.0002), lower grip pressure (3.0 ± 0.2 vs. 4.2 ± 0.5 kg/cm2; p = 0.0002), faster seal time (1.5 ± 0.4 vs. 11.6 ± 2.5 s; p < 0.0001), lower mean jaw temperature (109.7 ± 7.2 vs. 247.4 ± 8.6 °C; p = 0.0051), and faster cooling to 40 °C (53.6 ± 2.1 vs. 68.0 ± 3.5 s; p = 0.0051). SynchroSeal’s mean burst pressures after seal-and-transection and seal only modes were, respectively, 1169.1 ± 393.1 mmHg and 1159.2 ± 454.6 mmHg. Mean thermal spreads were, respectively, 1.2 ± 0.6 mm and 1.5 ± 0.55 mm. In the chronic animal study, 102 vessels were sealed; at 3 weeks post-procedure, there was no evidence of leakage or adverse events, such as non-target tissue thermal spread or tissue damage. In bariatrics cases, SynchroSeal was activated more frequently per case; however, its mean activation time was significantly shorter than Vessel Sealer Extend. No adverse events were reported for either device.ConclusionsSynchroSeal’s multifunctional design provides enhanced sealing and transection capabilities with an acceptable safety profile.

Photothermal-SR-Net: A Customized Deep Unfolding Neural Network for Photothermal Super Resolution Imaging

This article presents deep unfolding neural networks to handle inverse problems in photothermal radiometry enabling super-resolution (SR) imaging. The photothermal SR approach is a well-known technique to overcome the spatial resolution limitation in photothermal imaging by extracting high-frequency spatial components based on the deconvolution with the thermal point spread function (PSF). However, stable deconvolution can only be achieved by using the sparse structure of defect patterns, which often requires tedious, hand-crafted tuning of hyperparameters and results in computationally intensive algorithms. On this account, this article proposes Photothermal-SR-Net, which performs deconvolution by deep unfolding considering the underlying physics. Since defects appear sparsely in materials, our approach includes trained block-sparsity thresholding in each convolutional layer. This enables to super-resolve 2-D thermal images for nondestructive testing (NDT) with a substantially improved convergence rate compared to classic approaches. The performance of the proposed approach is evaluated on various deep unfolding and thresholding approaches. Furthermore, we explored how to increase the reconstruction quality and the computational performance. Thereby, it was found that the computing time for creating high-resolution images could be significantly reduced without decreasing the reconstruction quality by using pixel binning as a preprocessing step.

Research on thermal and central flame spread behaviors over insulation material EPS in different concave structure cases

The effect of different depth-width ratios, ?, on the flame spread over molded polystyrene (EPS) at the central place ignition was studied. The variation laws of characteristic parameters such as flame structure, flame height, flame spread rate, flame temperature and mass loss rate were analyzed. The experimental results show that at the central flame spread, the extinction, re-ignition, and re-burning were found for the upward flame except at ? = 1.5, while the downward flame didnot have these phenomena. At ? = 1.5, the stability of upward flame spread was the best, as the extinction didnot occur, and the flame spread rate was the fastest. When ? &lt;1.5, the extinction of upward flame could be sorted to flame instability, while when ? &gt;1.5, the extinction could be attributed to the more hot smoke effect. If the average flame height of upward increased, the average flame height of downward decreased, and vice versa. Inner flame pressure model was built, which could better explain the characteristics of mutual inhibition between upward and downward flame heights.

Safety of Helium-based Plasma Technology for Coagulation of Soft Tissue: A Retrospective Review.

The subdermal application of energy using a helium-based plasma radiofrequency (RF) device has been shown to improve skin laxity. Helium-based plasma RF technology (Renuvion; Apyx Medical, Clearwater, FL) utilizes RF to ionize helium into an electrically conductive plasma capable of coagulating and contracting soft tissue with high precision and minimal thermal spread. This study provides information on the early use of the new generation of electrosurgical generator (APYX-RS3) containing a feature that allows for quantification of the amount of energy delivered to tissue during treatments. To collate procedure details, treatment settings, and safety data in patients treated with a helium-based plasma device for soft tissue coagulation. A retrospective review was conducted of patients aged ≥ 18 years who underwent treatment with a helium-based plasma RF device (Renuvion) for soft tissue coagulation. Demographic data, procedure details, and adverse events were collected. Chart review identified 47 patients with an average age of 45 years and an average BMI of 25.8 kg/m2. The amount of energy (J) delivered per treatment area was greatest for abdomen, buttocks, and thighs, with an average of 13.7 kJ, 13.5 kJ, and 10.6 kJ, respectively. No serious, unexpected, or device-related AEs were reported. The use of the generator that quantifies the energy (joules) being applied during the procedure allows the provider to understand and optimize their energy usage. While further research is needed to establish the safety and efficacy of the device for skin tightening, this study provides important information regarding energy application.

Improving Voice Outcomes After Thyroid Surgery - Review of Safety Parameters for Using Energy-Based Devices Near the Recurrent Laryngeal Nerve.

Technological advances in thyroid surgery have rapidly increased in recent decades. Specifically, recently developed energy-based devices (EBDs) enable simultaneous dissection and sealing tissue. EBDs have many advantages in thyroid surgery, such as reduced blood loss, lower rate of post-operative hypocalcemia, and shorter operation time. However, the rate of recurrent laryngeal nerve (RLN) injury during EBD use has shown statistically inconsistent. EBDs generate high temperature that can cause iatrogenic thermal injury to the RLN by direct or indirect thermal spread. This article reviews relevant medical literatures of conventional electrocauteries and different mechanisms of current EBDs, and compares two safety parameters: safe distance and cooling time. In general, conventional electrocautery generates higher temperature and wider thermal spread range, but when applying EBDs near the RLN adequate activation distance and cooling time are still required to avoid inadvertent thermal injury. To improve voice outcomes in the quality-of-life era, surgeons should observe safety parameters and follow the standard procedures when using EBDs near the RLN in thyroid surgery

Innovative thermal management and thermal runaway suppression for battery module with flame retardant flexible composite phase change material

Thermal runaway severely affects the lithium batteries under conditions of non-normal forces or thermal abuse. In this study, a novel flame retardant flexible composite phase change material is successfully prepared, and a battery module based on it is designed and experimentally investigated. Herein, paraffin with high latent heat is performed as phase change material, Styrene-butadiene-styrene is employed as the supporting material, expanded graphite is used as the additive for thermal conductivity enhancement, and a flame retardant is utilized to suppress the heat diffusion and resistant flame. Experimental results reveal that a flame retardant flexible composite phase change material with 15 wt% flame retardant can achieve the optimum flame retardant effect, and its limiting oxygen index value can reach 35.9%. The battery thermal management with 15 wt% flame retardant composite phase change material can effectively avoid the heat accumulation of the battery module in the long cycle. In addition, thermal runaway trigger is simulated by heating rod at 200 °C, and the effect of the different composite phase change material modules on thermal runaway spread are compared. The result reveals that the flame retardant flexible composite phase change material could absorb and transfer the heat of the triggered battery timely and promptly, exhibiting a flame retardant effect necessary to avoid thermal runaway of the battery.

Sophisticated Dissection without Monopolar Scissors

<h3>Study Objective</h3> To demonstrate how the bipolar method allows for pinpoint dissection with minimal thermal spread in a variety of challenging operative scenarios in gynecology. <h3>Design</h3> Case presentations. <h3>Setting</h3> Urban general hospital in Japan. <h3>Patients or Participants</h3> From December 2018 to April 2021, we performed 485 robotic surgeries using the double bipolar method in a variety of procedures such as hysterectomy for benign pathology, robotic sacro-colpopexy and para-aortic and pelvic lymphadenectomy for cervical and endometrial cancer. <h3>Interventions</h3> Pinpoint dissection in the case of severe Douglas Pouch adhesion or bladder adhesion, transperitoneal lymphadenectomy and extraperitoneal para-aortic and pelvic lymphadenectomy and nerve-sparing radical trachelectomy is a great advantage. These challenging procedures require the elucidation of fine structures and well as accurate separation of adhered organs. The double bipolar method is accurate, powerful and efficient with minimal thermal spread. <h3>Measurements and Main Results</h3> Only one patient who had extensive adhesion due to previous surgery required surgery from postoperative peritonitis. All other patients recovered quickly and without complications. <h3>Conclusion</h3> Monopolar scissors are a standard robotic equipment, used by the majority of surgeons. Although monopolar scissors allow for good quality dissection, thermal spread is always a concern. The thermal spread is known to be source of intraoperative complications and reducing this problem is an important concern. As a result, we implemented the double bipolar method. Not only because of its pinpoint accuracy, but also because the cutting mechanism has minimal thermal spread which is desirable especially when dissection ultra-fine structures.

Transcervical Radiofrequency Ablation for Symptomatic Adenomyosis: A Case Report

<h3>Study Objective</h3> To demonstrate the use of a transcervical radiofrequency ablation (RFA) device approved for symptomatic uterine fibroids as a possible treatment for adenomyosis. <h3>Design</h3> A case report. <h3>Setting</h3> Community hospital affiliate of a large university hospital. <h3>Patients or Participants</h3> 35-year-old gravida-2 para-0 female with uterine fibroids and infertility, presenting with heavy menstrual bleeding, dysmenorrhea, and recent 1^st trimester miscarriage. Pelvic MRI showed a 12 cm uterus with a 2 cm endometrial polyp, 4.5 cm pedunculated fundal fibroid, and diffusely thickened posterior and fundal myometrium consistent with adenomyosis. <h3>Interventions</h3> The patient desired uterine-sparing surgical management and underwent a laparoscopy, hysteroscopy and transcervical RFA. <h3>Measurements and Main Results</h3> Laparoscopically, extensive posterior adenomyosis, a 4.5 cm pedunculated fibroid, and sub-centimeter exophytic fibroid were noted. Endometriosis and small left ovarian fibromas were incidentally diagnosed. Hysteroscopically, there was a 2 cm endometrial lesion with an otherwise normal endometrial cavity. The patient underwent laparoscopic myomectomy of 2 fibroids (without myometrial incision), excision of left ovarian fibromas, and excision of endometriosis in 2 areas, as well as hysteroscopic resection of the endometrial lesion. Ultrasound-guided transcervical RFA then targeted the thickened posterior myometrium with ablation of two adenomyotic regions (measuring 3.4 × 2.6 cm and 3.8 × 2.6 cm). Outgassing was visualized on intrauterine ultrasound images in these regions similar to ablated uterine fibroids and suggestive of successful adenomyosis ablation. Concomitant laparoscopy confirmed no thermal spread beyond uterine serosa. The patient was discharged home the same day. Final pathology revealed fibroids, endometriosis, ovarian spindle cell tumor, and products of conception. On follow-up evaluation, she had no postoperative complaints and no pain medication requirements beyond the immediate postoperative period. Assessment of long-term symptomatic improvement and fertility outcomes are ongoing. <h3>Conclusion</h3> Transcervical radiofrequency ablation is a promising uterine-sparing treatment for patients with adenomyosis. Additional research is warranted to assess long-term symptom improvement and pregnancy outcomes.

Experimental investigation on the fire and thermal smoke spread in tunnels: Effects of fire elevation

Previously, studies related to tunnel fires predominately concentrated on the fire at ground level while the risk of elevated fires caused by different vehicle heights was mostly ignored. In the current research, pool fires elevated at seven levels were experimentally studied in two reduced-scale model tunnels with both natural and longitudinal ventilation. Fuel burning rate, temperature profile, and thermal smoke stratification affected by the fire elevation were successively explored. Experimental results declared the major findings as 1) Fuel burning rate of the 8 cm × 8 cm pool fire was indistinctly affected by the fire elevation while it increased rapidly with the elevated height as pool size increased; 2) In the natural-ventilated tunnel, the maximum temperature significantly increased with the fire elevation and was found to be well predicted by the modified models with a linear correlation versus Q2/5Hd¯ or QD∗2/5·DfHd¯ and a constant value equal to 2.9. When longitudinal ventilation was activated, flame deflection, shortened back-layering length, and decreased maximum temperature were respectively observed. 3) Interface of the smoke-air layer was lifted, and thermal smoke stratification was promoted by the fire elevation. Good agreement was achieved between the present measurements and temperature quotient proposed by Newman. Correlation by using modified Froude number denoted different characteristics of smoke stratification of ground fire and elevated fire.