Slow Leak Research Articles

Transnasal Endoscopic Approach for Excision of Intracranial Nasal Dermoid Sinus Cysts.

Nasal dermoid sinus cysts (NDSCs) with intracranial extension in the form of dermal sinus tracts require careful and complete resection to prevent recurrence. Resection techniques necessitate adequate intracranial exposure, but morbidity associated with historical resection approaches has presented unique multidisciplinary challenges for surgeons treating cysts with intracranial extension. The authors primarily employed a transnasal approach through a midline nasal incision, utilizing endoscopic or microscopic access between the lateral cartilages for resection of NDSCs with intracranial extension. A retrospective review was completed for patients treated for NDSCs at the authors' pediatric quaternary referral center from 2017 to 2023. Data collection included demographics, comorbidities, perioperative data, pre and postoperative imaging, surgical outcomes, and complications. Eighteen patients with NDSCs with possible or confirmed intracranial extension were surgically treated from 2017 to 2023. Fifteen were treated with resection performed through a midline transnasal approach with endoscopic assistance, achieving successful total resection while avoiding nasal osteotomy or frontal craniotomy. One patient had a slow cerebrospinal fluid leak from an operative durotomy, successfully treated with a lumbar drain. No other complications occurred. No patients required transfusion. Incision length and postoperative scar burden were less than approaches that used osteotomies or craniotomies and demonstrated excellent cosmetic results. No patients have had cyst recurrence or required reoperation. A transnasal approach through a midline incision with endoscopic assistance is an effective approach for resection of NDSC with intracranial extension, but utility may vary with cyst size and complexity. This approach leverages appropriate exposure for resection with decreased morbidity and decreased incision length through avoidance of osteotomies.

A field study of manhole cover leakage.

Leaking manhole covers add inflow to sanitary sewer systems. These are the most accessible components of the sewer system, and so potentially the cheapest to repair or modify, to reduce inflow. There is, however, very little data regarding manhole cover leakage available to evaluate the cost-benefit of such an approach, and there is no field data. So, a multi-year field study of inflow was conducted. Two-hundred and fifty manholes in New York City and surrounding towns were tested. A key field observation in this study was that a dust and grit seal typically built up between the cover and the rim. This seal had a big impact on leakage rates. This made testing in-situ a necessity, and the test method had to preserve this seal. Due to the presence of the dust and grit seal, approximately 80% of the manholes tested showed no leakage. A further 15% had slow leaks. Only 5% had significant leaks.

Precision Leak Detection in Supermarket Refrigeration Systems Integrating Categorical Gradient Boosting with Advanced Thresholding

Supermarket refrigeration systems are integral to food security and the global economy. Their massive scale, characterized by numerous evaporators, remote condensers, miles of intricate piping, and high working pressure, frequently leads to problematic leaks. Such leaks can have severe consequences, impacting not only the profits of the supermarkets, but also the environment. With the advent of Industry 4.0 and machine learning techniques, data-driven automatic fault detection and diagnosis methods are becoming increasingly popular in managing supermarket refrigeration systems. This paper presents a novel leak-detection framework, explicitly designed for supermarket refrigeration systems. This framework is capable of identifying both slow and catastrophic leaks, each exhibiting unique behaviours. A noteworthy feature of the proposed solution is its independence from the refrigerant level in the receiver, which is a common dependency in many existing solutions for leak detection. Instead, it focuses on parameters that are universally present in supermarket refrigeration systems. The approach utilizes the categorical gradient boosting regression model and a thresholding algorithm, focusing on features that are sensitive to leaks as target features. These include the coefficient of performance, subcooling temperature, superheat temperature, mass flow rate, compression ratio, and energy consumption. In the case of slow leaks, only the coefficient of performance shows a response. However, for catastrophic leaks, all parameters except energy consumption demonstrate responses. This method detects slow leaks with an average F1 score of 0.92 within five days of occurrence. The catastrophic leak detection yields F1 scores of 0.7200 for the coefficient of performance, 1.0000 for the subcooling temperature, 0.4118 for the superheat temperature, 0.6957 for the mass flow rate, and 0.8824 for the compression ratio, respectively.

Critically synchronized brain waves form an effective, robust and flexible basis for human memory and learning

The effectiveness, robustness, and flexibility of memory and learning constitute the very essence of human natural intelligence, cognition, and consciousness. However, currently accepted views on these subjects have, to date, been put forth without any basis on a true physical theory of how the brain communicates internally via its electrical signals. This lack of a solid theoretical framework has implications not only for our understanding of how the brain works, but also for wide range of computational models developed from the standard orthodox view of brain neuronal organization and brain network derived functioning based on the Hodgkin–Huxley ad-hoc circuit analogies that have produced a multitude of Artificial, Recurrent, Convolution, Spiking, etc., Neural Networks (ARCSe NNs) that have in turn led to the standard algorithms that form the basis of artificial intelligence (AI) and machine learning (ML) methods. Our hypothesis, based upon our recently developed physical model of weakly evanescent brain wave propagation (WETCOW) is that, contrary to the current orthodox model that brain neurons just integrate and fire under accompaniment of slow leaking, they can instead perform much more sophisticated tasks of efficient coherent synchronization/desynchronization guided by the collective influence of propagating nonlinear near critical brain waves, the waves that currently assumed to be nothing but inconsequential subthreshold noise. In this paper we highlight the learning and memory capabilities of our WETCOW framework and then apply it to the specific application of AI/ML and Neural Networks. We demonstrate that the learning inspired by these critically synchronized brain waves is shallow, yet its timing and accuracy outperforms deep ARCSe counterparts on standard test datasets. These results have implications for both our understanding of brain function and for the wide range of AI/ML applications.

Aspergillus in COVID-19 intensive care unit; what is lurking above your head?

IntroductionThrough routine respiratory samples surveillance among COVID-19 patients in the intensive care, three patients with aspergillus were identified in a newly opened general intensive care unit during the second wave of the pandemic. MethodologyAs no previous cases of aspergillus had occurred since the unit had opened. An urgent multidisciplinary outbreak meeting was held. The possible sources of aspergillus infection were explored. The multidisciplinary approach enabled stakeholders from different skills to discuss possible sources and management strategies. Environmental precipitants like air handling units were considered and the overall clinical practice was reviewed. Settle plates were placed around the unit to identify the source. Reports of recent water leaks were also investigated.ResultsGrowth of aspergillus on a settle plate was identified the potential source above a nurse’s station. This was the site of a historic water leak from the ceiling above, that resolved promptly and was not investigated further. Subsequent investigation above the ceiling tiles found pooling of water and mould due to a slow water leak from a pipe.ConclusionWater leaks in patient areas should be promptly notified to infection prevention. Detailed investigation to ascertain the actual cause of the leak and ensure any remedial work could be carried out swiftly. Outbreak meetings that include diverse people with various expertises (clinical and non-clinical) can enable prompt identification and resolution of contaminated areas to minimise risk to patients and staff. During challenging pandemic periods hospitals must not lose focus on other clusters and outbreaks occurring simultaneously.

The Wound of Time

The Wound of Time

Writing About the Shapes of Conflict: War and Technocracy in the Twenty-First Century

What are the shape(s) of warfare and conflict in the allegedly post-historical, post-human, technocratic age? In a world altered by the technocratic paradigm, has our realist optic, founded on a witnessing that focuses on the surface appearance of things and a rhetoric framed by neo-liberal epistemology and desires, blinded us to the current changeable nature(s) and layerings of war and conflict? War is either seen as an abnormal happening in a faraway country, often defined as a dispute and not a war, or else it alters from a spectacular coordination of brute violence to a socio-economic inducement of fear, panic, social mobilisation/dispersion, and control in the particles of everyday life. During long periods of slow conflict nations leak away, people become metronomes, cultures are sapped of resilience, languages evaporate, existences are rendered irrelevant. How does writing bear witness to this spectrum of violence and reveal the technocratic paradigm underlying the sutures?

Two Patients Colonised with Absidia Corymbifera in an Intensive Care Unit Likely Secondary to an Abnormally Plumbed Renal Dialysis Point

Background Two adult patients within our adult intensive care unit grew Absidia corymbifera from clinical samples 24 hours apart. Both patients were colonised with the organism although one patient with a serious underlying condition did receive antifungal therapy. Due to the serious nature of Mucormycosis an infection control investigation was undertaken to identify and address any underlying sources with the aim of preventing further cases. Methods Visual inspection of the patient's environment was undertaken for investigation of water ingress or visible mould. Other investigations included air sampling and sampling of bed linen and shared equipment between patients. Results On review of one of the patient bedrooms an area of recent water ingress was identified. This was a plumbed in dialysis point which on further exploration had an abnormal plumbing collection to a sluice. As a result, there had been reflux of bed pan pulp into the wall space. Air sampling was negative. Swabs of linen were also negative and an ultrasound machine which was the only shared piece of equipment was also excluded. There was no construction work in the vicinity and checks on the patient's room ventilation parameters were satisfactory Conclusions It is likely the source of Absidia corymbifera was water ingress from an abnormally plumbed dialysis point in one of the patient bedrooms. Damp bed pan pulp supports the growth of fungi and if not removed within 72 hours will support fungal proliferation. Mould accumulating in a wall due to a slow water leak is thought to have played a role in cases of Mucor in the published literature. Fungal spores are released in bursts and travel far and wide which would explain colonisation in another patient in the unit at the same time. Following removal of the pulp and remedial plumbing no further cases were noted.

Study on field demonstration of high‐sensitivity SF6 leakage detection method for gas insulated switchgear

AbstractSF6 gas is widely used in power equipment such as gas insulated switchgear or gas circuit breaker. However, its global warming potential is 23,500 times higher than that of CO2. In consideration of environmental protection, detection of SF6 gas leakage with high sensitivity is necessary. The authors proposed an algorithm to accurately estimate the average gas temperature from the tank surface temperature for establishing a high‐sensitive SF6 slow leak detection technology. Since the gas temperature depends on the temperature of the conductor, the algorithm was characterized by estimating the gas temperature from the tank surface temperature and the load current. The relationship among the tank surface temperature, the gas temperature, and the current was preliminarily investigated by the use of the thermal fluid analysis and stored in the database. By use of this method, the fluctuation of the converted pressure in the basic examination test was suppressed to 20% as compared with that without considering the current. In addition, database was also created from the machine learning of field test result in substitution. In the field test, it was confirmed that the detection time of 0.5%/year slow leak could be detected in about 8 months by considering the load current.

PRIMARY SPONTANEOUS PNEUMOTHORAX IN A YOUNG HEALTHY MALE SECONDARY TO WEIGHT LIFTING: A CASE REPORT AND REVIEW OF THE LITERATURE

SESSION TITLE: Medical Student/Resident Disorders of the Pleura Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: A primary spontaneous pneumothorax (PSP) is defined as a pneumothorax that occurs without clinically apparent underlying lung disease. Though the etiology of PSP remains a subject of debate, several risk factors have been identified, including tobacco use, male sex, low body mass index, and height [1]. PSP is also infrequently reported secondary to athletic activity, with 10-20% of cases due to heavy exertion, such as running [2]. However, PSP has rarely been reported secondary to weightlifting, with fewer than 5 cases previously known to be published. Here we present a case of PSP secondary to weightlifting in a young healthy male without known risk factors. CASE PRESENTATION: A 30 year-old male active duty member of the Air Force presented to the emergency department with sudden-onset dyspnea and pleuritic chest pain that occurred during a Valsalva maneuver while bench pressing approximately 80 kilograms. Vital signs were within normal limits upon arrival to the emergency department. Plain films of the chest revealed a left apical primary spontaneous pneumothorax with an apical-pleural distance of 7.7 cm. The patient was placed on oxygen, and an 8 French chest tube was placed, which remained on a Heimlich valve overnight. Computed tomography (CT) scan of the chest without contrast obtained the day after presentation demonstrated near-complete resolution of the pneumothorax without evidence of peripheral pleural blebs. When he presented for follow up one month later, he remained asymptomatic and a repeat plain film did not demonstrate pneumothorax recurrence. The patient denied history of smoking, significant medical history, recent high altitude flying, or any other known risk factors for spontaneous pneumothorax. DISCUSSION: Despite decades of study, the disease process remains poorly understood. Proposed mechanisms include emphysema-like changes leading to rupture of subpleural blebs and absence of mesothelial cells leading diffuse “pleural porosity” leading to slow leak of air [3]. The mechanism of weightlifting-induced pneumothorax is equally unclear, but is theoretically due to increased intrathoracic pressure with long breath holds during Valsalva, as has previously been described in cannabis users. Weightlifting is rarely described as an etiology for PSP, but characterization of this etiology could be important in management, as treatment often differs depending on risk of recurrence. More research is needed to examine specific phenotypes and mechanisms of PSP in order to appropriately tailor management. CONCLUSIONS: Primary spontaneous pneumothorax has been associated with heavy exertion and rarely with weightlifting, but further research is needed to examine this phenotype to tailor treatment based on recurrence risk. Reference #1: Sahn S.A., Heffner J.E. Spontaneous pneumothorax. N Engl J Med 2000;342:868-74. Reference #2: Simoneaux S.F., Murphy B.J., Tehranzadeh J. Spontaneous pneumothorax in a weight lifter: a case report. Am J Sports Med: 1990;18(6):647-48. Reference #3: Grundy S, Bentley A, Tschopp J. Primary spontaneous pneumothorax: a diffuse disease of the pleura. Respiration: 2012;83(3);185-89. DISCLOSURES: No relevant relationships by John Hunninghake, source=Web Response No relevant relationships by Lauren Sattler, source=Web Response

Propensity and quantification of aerosol and droplet creation during phacoemulsification with high-speed shadowgraphy amid COVID-19 pandemic.

To study propensity of aerosol and droplet generation during phacoemulsification using high-speed shadowgraphy and quantify its spread amid COVID-19 pandemic. Aerosol and droplet quantification laboratory. Laboratory study. In an experimental set-up, phacoemulsification was performed on enucleated goat eyes and cadaveric human corneoscleral rims mounted on an artificial anterior chamber. Standard settings for sculpt and quadrant removal mode were used on Visalis 100 (Carl Zeiss Meditec AG). Microincision and standard phacoemulsification were performed using titanium straight tips (2.2 mm and 2.8 mm in diameter). The main wound incisions were titrated equal to and larger than the sleeve size. High-speed shadowgraphy technique was used to detect the possible generation of any droplets and aerosols. The visualization and quantification of size of the aerosols and droplets along with calculation of their spread were the main outcome measures. In longitudinal phacoemulsification using a peristaltic pump device with a straight tip, no aerosol generation was seen in a closed chamber. In larger wounds, there was a slow leak at the main wound. The atomization of balanced salt solution was observed only when the phacoemulsification tip was completely exposed next to the ocular surface. Under this condition, the nominal size of the droplet was approximately 50 µm, and the maximum calculated spread was 1.3 m. There was no visible aerosol generation during microincision or standard phacoemulsification. Phacoemulsification is safe to perform in the COVID-19 era by taking adequate precautions against other modes of transmission.

Numerical simulations on the leakage and diffusion of tritium

Based on the knowledge that the surroundings of tritium leakage and diffusion in hydrogen storage vessels can be either open space or closed space, the subsonic jet flow of a slow tritium leak from a hydrogen storage bed under open and closed spatial conditions is simulated by Fluent finite element software. Furthermore, the quantitative relationship between mass flow rate and time is established by using the user defined function (UDF) to compile interface codes. The subsonic tritium jet, velocity profiles, tritium diffusion distance, and the tritium concentration along the jet trajectory are obtained in two different scenarios (open space and closed space). The results show that the closed space inhibits the vertical convection diffusion of tritium and has a favorable improving effect on the horizontal convection diffusion of tritium, whereas the open space has the opposite influence on the convection diffusion of tritium. In addition, an eddy current whirlpool develops under the closed space condition. The concentration distribution along the jet center line can be significantly influenced by the spatial boundary condition and leak aperture. An increase of leak aperture facilitates vertical diffusion of tritium and the velocity near the leakage hole. The oblique downward wind and horizontal wind lead to an enhancement of tritium cloud horizontal drifting. The oblique upward wind can be considered as a method to effectively dilute leaked tritium concentration.

Quantitative Analysis Method for Corrosion and Patina Progression on Plumbing Components during Long-Term Connection Leaks from Potable Water Supply Systems

The modern field of Forensic Engineering evaluates the origin, cause, and duration of failed building components. As many failed components are subject to insurance claims and legal probes, a scientific methodology for evaluating such events is inherently valuable. Due to the potential for widespread interior finish damage, failed plumbing supply components are commonly encountered during forensic evaluations. Plumbing pipes themselves and properly soldered fittings rarely fail. Consequently, many failures correspond to mechanical fittings which form connections from pipes to plumbing fixtures. The results of this study provide a scientific methodology to evaluate the duration of connection leaks by quantifying the extent of corrosion, patina, and accumulated deposits on various components by creating and evaluating slow plumbing supply component connection leaks.

History of very thick film and bulk sample group IIIB, IVB, VB, and rare earth materials for various vacuum applications

Thick occluder film and bulk hydride materials are extremely hard to produce without flaking or cracking. This paper discusses methods of how to prepare thick films and bulk samples (i.e., rods and wires) that have reduced stress for many applications. These include accelerator research for cancer therapy, intense neutron sources, particle-beam fusion diagnostic beam focusing studies, and mass spectrometer calibration. Thick films of ∼(≥3000 to 150 000 nm thickness of various hydrides are sensitive to oxidation and are easily contaminated by improper handling. They must be specially prepared to reduce internal stresses due to temperature variations during processing, stresses due to hydriding, and substrate configuration (i.e., curved surfaces). Discussed are techniques developed at the General Electric Neutron Devices Department, in Largo, FL, in the mid-1970s to the late 1990s to produce flaking and crack free samples of thick films and bulk samples. Items studied include Er, Sc, and Ti thick film hydrides on a Cr underlay, on various substrates, Er and Sc bulk rod samples for the first basic material heat capacity and thermal diffusivity studies as a function of hydride loading, Nb and V wires in bundles of ∼30 wires, for the first tritide neutron vibration spectra studies, and Ti wires for mass spectrometer calibration studies. Film samples were prepared by standard E-beam evaporation techniques and then non-air-exposure loaded. Bulk samples were loaded with a Sievert's precise gas quantity loading system. To produce reduced intrinsic stress (strain) in samples of Er, Sc, and Ti thick films, and bulk samples of Er, Sc, Nb, V, and Ti, special processing employing slow bakeout heating and cool down rates, slow film deposition rates, slow leak in pressure hydriding rates, followed by slow cooling rates to room temperature were used. Using the process described, very successful results were obtained.

2017 WSGC Elijah High-Altitude Balloon Payload

The 2017 WSGC Elijah High-Altitude Balloon Payload Fellowship focused on three different topics for high altitude research: Modular Payload Design, Balloon Dynamics, and Energy Harvesting. A modular payload system was created using advanced manufacturing methods, which improved assembly and field operation. Minor structural fracturing was observed upon recovery. All instrumentation recovered were functioning. Vertical flight dynamics of a high-altitude balloon were studied to create a model that was compared against experimental data. Predictions did not accurately replicate GPS altitude data, possibly due to incorrect internal-balloon pressure readings and underlying assumptions. Habitability of high-altitude environments were explored by monitoring insect analog in pressurized environment. A slow pressure leak induced insects into a comatose state. Radiation was detected visually with camera.Investigated energy generation from balloon kinematics. Flight data not obtained but flight simulation data produced average voltage = 0.0039 V and total energy = 245.13 J.

Detecting the permafrost carbon feedback: talik formation and increased cold-season respiration as precursors to sink-to-source transitions

Abstract. Thaw and release of permafrost carbon (C) due to climate change is likely to offset increased vegetation C uptake in northern high-latitude (NHL) terrestrial ecosystems. Models project that this permafrost C feedback may act as a slow leak, in which case detection and attribution of the feedback may be difficult. The formation of talik, a subsurface layer of perennially thawed soil, can accelerate permafrost degradation and soil respiration, ultimately shifting the C balance of permafrost-affected ecosystems from long-term C sinks to long-term C sources. It is imperative to understand and characterize mechanistic links between talik, permafrost thaw, and respiration of deep soil C to detect and quantify the permafrost C feedback. Here, we use the Community Land Model (CLM) version 4.5, a permafrost and biogeochemistry model, in comparison to long-term deep borehole data along North American and Siberian transects, to investigate thaw-driven C sources in NHL (> 55∘ N) from 2000 to 2300. Widespread talik at depth is projected across most of the NHL permafrost region (14 million km2) by 2300, 6.2 million km2 of which is projected to become a long-term C source, emitting 10 Pg C by 2100, 50 Pg C by 2200, and 120 Pg C by 2300, with few signs of slowing. Roughly half of the projected C source region is in predominantly warm sub-Arctic permafrost following talik onset. This region emits only 20 Pg C by 2300, but the CLM4.5 estimate may be biased low by not accounting for deep C in yedoma. Accelerated decomposition of deep soil C following talik onset shifts the ecosystem C balance away from surface dominant processes (photosynthesis and litter respiration), but sink-to-source transition dates are delayed by 20–200 years by high ecosystem productivity, such that talik peaks early (∼ 2050s, although borehole data suggest sooner) and C source transition peaks late (∼ 2150–2200). The remaining C source region in cold northern Arctic permafrost, which shifts to a net source early (late 21st century), emits 5 times more C (95 Pg C) by 2300, and prior to talik formation due to the high decomposition rates of shallow, young C in organic-rich soils coupled with low productivity. Our results provide important clues signaling imminent talik onset and C source transition, including (1) late cold-season (January–February) soil warming at depth (∼ 2 m), (2) increasing cold-season emissions (November–April), and (3) enhanced respiration of deep, old C in warm permafrost and young, shallow C in organic-rich cold permafrost soils. Our results suggest a mosaic of processes that govern carbon source-to-sink transitions at high latitudes and emphasize the urgency of monitoring soil thermal profiles, organic C age and content, cold-season CO2 emissions, and atmospheric 14CO2 as key indicators of the permafrost C feedback.

Redox-controlled carbon and phosphorus burial: A mechanism for enhanced organic carbon sequestration during the PETM

Geological records reveal a major perturbation in carbon cycling during the Paleocene–Eocene Thermal Maximum (PETM, ∼56 Ma), marked by global warming of more than 5 °C and a prominent negative carbon isotope excursion of at least 2.5‰ within the marine realm. The entire event lasted about 200,000 yr and was associated with a massive release of light carbon into the ocean–atmosphere system over several thousands of years. Here we focus on the terminal stage of the PETM, during which the ocean–atmosphere system rapidly recovered from the carbon cycle perturbation. We employ a carbon-cycle box model to examine the feedbacks between surface ocean biological production, carbon, oxygen, phosphorus, and carbonate chemistry during massive CO2 release events, such as the PETM. The model results indicate that the redox-controlled carbon–phosphorus feedback is capable of producing enhanced organic carbon sequestration during large carbon emission events. The locale of carbon oxidation (ocean vs. atmosphere) does not affect the amount of carbon sequestered. However, even though the model produces trends consistent with oxygen, excess accumulation rates of organic carbon (∼1700 Pg C during the recovery stage), export production and δ13C data, it fails to reproduce the magnitude of change of sediment carbonate content and the CCD over-deepening during the recovery stage. The CCD and sediment carbonate content overshoot during the recovery stage is muted by a predicted increase in CaCO3 rain. Nonetheless, there are indications that the CaCO3 export remained relatively constant during the PETM. If this was indeed true, then an initial pulse of 3,000 Pg C followed by an additional, slow leak of 2,500 Pg C could have triggered an accelerated nutrient supply to the surface ocean instigating enhanced organic carbon export, consequently increasing organic carbon sequestration, resulting in an accelerated restoration of ocean–atmosphere biogeochemistry during the termination phase of the PETM.

Is peritoneal dialysis feasible after laparotomy in children? A case-control series to compare outcomes

Peritoneal dialysis (PD) is the modality of choice for children with end-stage renal disease (ESRD) awaiting renal transplant; however, this option is sometimes avoided for those with previous laparotomy. The goal of this study was to compare the outcomes of PD in patients with and without previous laparotomy. Twenty-four patients who had been started on peritoneal dialysis were retrospectively analysed. Group LAP consisted of six patients with previous laparotomy, and Group NO-LAP of 18 controls with either retroperitoneal or no abdominal surgery. The percentage of theoretical maximum volume of infusion, time to reach it, complications (infection and drainage difficulties), and number of catheters needed to finish therapy were analysed. The characteristics of patients and technique of insertion are presented in Table. The percentage of maximum theoretical volume of infusion was similar in both groups. Median of catheter survival was similar in both groups. Complications were divided into malfunction (slow drainage, obstruction or leak) and infection. Incidence of complications per catheter and per month of dialysis was ten times lower in Group NO-LAP. Peritoneal dialysis failed in one patient with recurrent intraperitoneal adhesions after adhesiolysis in Group LAP. Despite a higher incidence of complications (malfunction and infections), PD remains an acceptable option after laparotomy. In this series, it was sufficient in achieving adequate filtration in five patients.

Regional Heat Exchange During a Dry Suit Glove Failure in Cold Water Immersive Diving

Dry suit failures causing wet hands during cold-water diving can limit manual dexterity, affect comfort, or result in cold injury or hypothermia. While dry suit leaks are a known problem in the field, it is rarely captured and measured in controlled lab settings. PURPOSE: We quantified regional heat exchange with a glove leak while diving in cold water with thermal protective equipment in the form of a water-perfused tube suit (WPT). METHODS: A healthy male subject was immersed supine, just below the surface of the water (1.3±0.01 °C), for 115 min while wearing a WPT supplied with 37.8 °C water and standard passive insulation under a dry suit. There was a slow leak at both wrists, resulting in wet gloves against the skin that was sensed by the subject within 7 min of immersion. The WPT was instrumented to measure 48 water temperatures for regional thermal exchange. Skin temperature (Ts) in 13 regions and rectal temperature (Tr) were measured via thermistors. All data were analyzed after Ts stabilized 30 min into immersion. RESULTS: The WPT delivered a linear increase of heat energy (619±26 W). This maintained Tr, which only decreased by ~0.24 °C, and mean Ts, which was stable at 33.3±0.1 °C. Ts including foot, calf, leg, abdomen, chest, upper and lower back, arm, and head remained stable, but forearm, hand, thumb and pinky Ts decreased over time; however, all Ts remained well above tissue injury level with the coldest being the pinky, which was ~22.3 °C at the end of the immersion. The WPT delivered the following mean proportions of heat (all < ±1%): head=10%, chest=8%, back=14%, arms=12%, forearms=9%, hands=12%, anterior leg/lower leg=8/5%, posterior leg/lower leg=10/5%, and feet=6%. The leak caused 12% of heating resources to be devoted to hands, which made up only 3% of body surface area. CONCLUSION: For the first time, regional heat exchange was quantified with a specially designed WPT during a common cold-water diving scenario in which there is a leak wetting the hands. Ts and Tr remained in safe limits and/or unchanged as a result of heat delivery supplied by the WPT. Importantly, the forearm, hand and finger regions were successfully kept warm by the WPT despite the leak. However, there was a 2.7-fold larger amount of heat required per unit surface area to the wet hands than to the dry extremities - the feet. Supported by NAVSEA N0002416WX02277.

Experimental study on R32 leakage and diffusion characteristic of wall-mounted air conditioners under different operating conditions

With good thermal performance and environmental characteristics, R32 is an alternative refrigerant of R22, but its application is limited by its flammability. In view of indoor security, this paper analyzed the leakage and diffusion of R32 of wall-mounted air conditioners under different operating conditions. The impact of air supply velocities and the leakage hole positions on the concentration distribution was also analyzed when the refrigerant leaks from the indoor unit while the air conditioner is operating. The results show that the leakage rate of R32 decreases with air conditioner operation time. The leakage process of refrigerant under the operating conditions can be classified into a fast leak stage and a slow leak stage. When the refrigerant leaks from the inlet pipe of the evaporator, the leakage rate is higher than that from the outlet pipe of the evaporator. This paper also analyzed the impact of air supply velocities on the concentration distribution and obtained the concentration distribution under different operating conditions. The concentration distribution was compared when the R32 leaks from different positions. Then, the indoor security was evaluated when R32 leaks from an operating air conditioner. And the results suggest that the combustible zone only appears near the leakage hole and the duration of the combustible zone is very short. We can infer that the fire risk of R32 as the alternative refrigerant of an air conditioner is very low under the general operation conditions.