Good Condition Research Articles

Specialization of a new flux-based approach to thermal problems. Numerical study of glass façades of buildings with cast shadows

Uneven temperature distributions in the glass panes of building façades can induce thermal stresses exceeding material strength, a critical condition usually referred to as “thermal shock”. Here, we specialize in architectural glazing a recently-proposed flux-based variational approach to thermal problems, by considering heat exchanges resulting from climatic actions, in particular the variability of environmental temperatures and solar radiation, influenced by the shielding of cast shadows. The finite element implementation is facilitated because the unknown field is the heat displacement, whose time derivative is the heat flux, which is much smoother than the temperature field, on which the classical approach via Fourier’s law is based. A custom in-house-made FEM code is used to determine the effect of size and shape of cast shadows on temperature distribution in monolithic and laminated glass panes, also coupled in insulating glass units. We find that the temperature difference between irradiated and shadowed regions is only mildly influenced by the shape and size of the shadows, but the glass thickness determines the width of the transition zone and, hence, the temperature gradient. Practical rules for the design of glass façades are tentatively proposed.

Exploring the feasibility of using fluidized bed homogeneous crystallization technology to recover sulfate ions from briny water as calcium sulfate pellets

The increasing salinity of water sources poses significant operational and environmental challenges, highlighting the importance of developing efficient methods for recovering [SO42−] ions from briny wastewater. In this study, the potential of fluidized bed homogeneous crystallization (FBHC) technology for recovering [SO42−] ions from briny water is explored. FBHC is an innovative technique that enhances scalability and separation efficiency by promoting the growth of crystalline particles in a fluidized state. To achieve maximum [SO42−] recovery and maintain stable fluidized bed conditions, a pH of 8 is recommended. A removal ratio (RR) of 71 % was recorded at a [SO42−] concentration of 0.14 M. Various [SO42−] concentrations exhibited a molar ratio (MR) of [Ca2+]/[SO42−] = 1.5. Smaller particles, which are more soluble and exhibit less nucleation, are typically formed under conditions with lower pH and [Ca2+] levels. Intermediate-sized particles are favored at neutral to slightly alkaline pH levels and near-stoichiometric [Ca2+]/[SO42−] MR. Greater calcium content and higher pH values promote the development and agglomeration of larger particles, with 50 % of the particles exceeding an average size of 0.38 mm. In the XPS study of CaSO4 crystals (gypsum), the Ca 2p1/2 and Ca 2p3/2 peaks are observed at binding energies of 351.5 eV and 347.7 eV, respectively. Gypsum is identifiable due to the presence of clear and distinct peaks in XRD patterns. SEM analysis reveals the coexistence of amorphous patches and tiny crystalline domains on the surface. These gypsum crystals resemble stacked needle-like structures accompanied by small, powdery crystals. In an acidic environment, the primary phase is CaSO4·2H2O, which generates well-formed, elongated, or tabular crystals that are characteristic of gypsum. The FBHC process, characterized by a high crystallization ratio (CR = 68 %) and the recovery of crystal pellets (>0.3 mm), significantly reduces sludge production compared to traditional chemical precipitation methods. Its cost-effectiveness and recoverability make FBHC a promising technology for the recovery of sulfate ions from briny wastewater.

Laboratory findings predictive of critical illness in hospitalized COVID-19 patients in Tunisia

Background COVID-19 disease has spread rapidly worldwide, causing high mortality. Accessible biomarkers capable of early identification of patients at risk of severe form are needed in clinical practice. The aim of the study was to determine the biological markers that predict a critical condition. Methods Retrospective study including patients with confirmed COVID-19 hospitalized between September 2020 and June 2021. The primary endpoint was progression to critical status within 7 days from admission. We defined two groups: Critical group: Patients who developed a critical condition or died or transferred to the ICU before or at 7th day. Non-critical group: Patients who remained in non-critical respiratory status until 7th day or discharged before or at 7th day. Results Our study included 456 patients, with a sex ratio of 1.32 and an average age of 62 years. At the 7th day of hospitalization, 115 (25.2%) patients were in the critical group and 341 (74.8%) patients were in the non-critical group. The univariate logistic regression indicated that laboratory findings between non-critical and critical groups showed that C-reactive protein (CRP) (p=0.047), D-Dimer (p=0.011), creatinine (0.026), creatine kinase (p=0.039), lactate dehydrogenase (p=0.04), and troponin (p=0.001) were all higher among patients in critical group. However, lymphocyte (p<0.001) and platelet (p<0.001) counts were significantly lower among the critical group. Multivariate logistic regression model, identified four independent risk factors: lymphopenia (OR=2.771, 95%CI=1.482-5.181, p=0.001), Neutrophil to Lymphocyte Ratio (NLR) (OR=2.286, 95%CI=1.461-3.578, p<0.001), thrombocytopenia (OR=1.944, 95%CI=1.092-3.459, p=0.024), and CRP>71.5 (OR=1.598, 95% CI=1.042-2.45, p=0.032) were associated to critical group. Conclusions Our results show the predictive value of lymphopenia, thrombocytopenia, high NLR and CRP levels to evaluate the prognosis of COVID-19 pneumonia. A prognostic score could be proposed for guiding clinical care and improving patient outcomes.

Marine Operations in the Norwegian Sea and the Ice-Free Part of the Barents Sea with Emphasis on Polar Low Pressures

The Arctic Seas are attractive for shipping, fisheries, and other marine activities due to the abundant resources of the Arctic. The shrinking ice cover allows for the opening of activities in increasingly larger areas of the Arctic. This paper evaluates the possibility of executing all-year complex marine activities, here termed “marine operations”, in the Norwegian Sea and the ice-free part of the Barents Sea. The approach used during the preparation of this review paper is to identify constraints to marine operations so users can be aware of the limitations of performing such operations. The weather conditions in the Norwegian Sea and the Barents Sea are well known, and these seas are considered representative of ice-free or partly ice-free Arctic Seas with considerable marine activities. Similar conditions could be expected for other Arctic Seas during periods without ice cover. Marine operations require safe and stable working conditions for several days. The characteristics of marine operations are discussed, and the particulars of the Norwegian Sea and the Barents Sea physical environments are highlighted. Emphasis is on the wind and wave conditions in unpredictable polar low-pressure situations. Furthermore, situations with fog are discussed. The large uncertainties in forecasting the initiation and the tracks of polar lows represent the main concern for executing marine operations all year. Improvements in forecasting the occurrence and the path of polar lows would extend the weather window when marine operations could be carried out. Discussions of the potential for similar conditions in the wider Arctic Seas during ice-free periods are presented.

Ultrafast bounce of particle-laden droplets.

The rebound of liquid droplets on solid surfaces exhibits behavior reminiscent of elastic spheres, albeit with distinct contact dynamics. While the rapid detachment of droplets from surfaces holds significant relevance for various applications, previous endeavors relying on engineered surfaces can only reduce the contact time to several milliseconds, primarily due to capillary effects dominating droplet bounce. Here, we present ultrafast rebound by designing heterogeneous core-shell droplets encapsulating a particle (DEP), which achieves an unprecedentedly short contact time of 0.3 ms and 0.05 ms with polydimethylsiloxane and glass particles, respectively. This remarkable contact-time reduction is universally applicable to diverse systems, including both water and oil droplets, elastic and rigid particles, super-repellent and superlyophilic surfaces, and is effective across a wide range of impact velocities. Beyond exhibiting liquid-like dynamics, DEP manifests solid-like behavior owing to asynchronized motions between the particle and the droplet, which effectively breaks down the dominance of capillarity. With systematic experimental and analytical studies, we delineate contact times in three bouncing regimes and identify critical conditions governing regime transitions. DEP amalgamates the bouncing dynamics of both solids and liquids, offering a robust and versatile strategy for tailoring contact time to suit diverse applications involving solid-liquid composite systems.

COMPARATIVE ANALYSIS OF COVID-19 PATIENTS DURING DELTA AND OMICRON WAVES OF COVID-19 PANDEMIC: AN EXPERIENCE FROM RURAL TERTIARY CARE HOSPITAL IN NORTH INDIA

Objective: In this study, an effort has been made to find out possible clinical parameters that may have played role in differences in the disease outcome in the delta and omicron waves. Methods: This is a retrospective observational study conducted at a rural tertiary care center of North India. We recorded sociodemographic and clinicopathological parameters of the admitted patients during delta and omicron waves in India. The outcome measures were demographic, baseline clinical, disease severity, ICU admissions and hospital mortality. Results: In our study, 1731 patients were tested positive for SARS-CoV-2, out of which 16 patients were admitted during the omicron wave and 878 admissions during the delta wave. In delta wave, the ratio of male to female was 1:2 and in omicron wave, it was 1:3. There were 271 deaths in delta wave and 2 deaths in omicron wave. A significantly lower number of admissions were noted during omicron wave (p<0.001). Patients without previous history of COVID-19 and unvaccinated status had significantly higher admission (p<0.001). The admission rate among comorbid patients was also significantly low in the omicron wave (p<0.001). 251 patients had one or more comorbidities and were mostly in severe (13.4%) or critical (88.4%) conditions in delta wave while among 13 comorbid patients in omicron wave, 7.7% were in severe and 15.4% were in critical condition. Conclusion: The hospital admissions were very low in comparison to delta wave. During delta wave, the degree of severity and number of deaths were also very high.

Centrifugal Compressor Surge in Innovative Heat Pump: Fluid Dynamic and Vibrational Analysis

Abstract In the current energy scenario, it is necessary to reduce fossil fuel consumption to achieve the far-sighted and stringent decarbonization goals. To date, heat is mainly produced through fossil fuels. Alternatively, electrically driven heat pumps can exploit renewable power to recover environmental and waste heat, offering energy efficient and environmentally friendly heating and cooling for applications ranging from domestic and commercial buildings to process industries. For this reason, they are expected to play a primary role in complementing or displacing natural gas boilers in the residential and industrial sectors in the near future. Centrifugal compressors are already used as prime movers of the working fluid in heat pumps, thanks to their industrial replicability, compact size, affordable costs, and good performance in terms of efficiency and low noise. However, they are subject to instabilities such as surge and stall like any other dynamic compressor and these phenomena develop quite differently than in classic open-loop systems such as gas turbines. In fact, such peculiarity is mainly due to the closed-loop configuration with real gases in two-phase conditions, occurring in typical heat pump cycles. In addition, heat exchangers also contribute to make these phenomena different from what is commonly studied. Compressor surge in closed-loop heat pump systems has received lower attention than other applications by the engineering community, lacking dedicated experimental characterization, and clear exposition of the phenomenon. The aim of this paper is to experimentally investigate the behavior of a centrifugal compressor installed into an innovative close loop heat pump system under stable and unstable conditions from both vibrational and fluid-dynamic points of view. The impact of the main process parameters on the evolution of the instability is shown, highlighting how surge cycles change by varying system operating conditions. The energy contents of surge cycles and pressure fluctuations are highlighted, using data postprocessing techniques such as fast Fourier transform and phase locked average. The vibro-acoustic analysis enrich the comprehension of the phenomena. The experimental results shown in this paper can be a basis for the future development of validated mathematical models of closed-loop heat pumps systems equipped with dynamic compressors operating under stable and unstable operating conditions.

Near-Time Digital Mapping for Geoforensic Searches

Inadequate base maps with poor scale or low resolution demonstrate the need for contemporary topographic maps when conducting geological mapping. In neotectonic regimes and areas of dynamic geomorphology, archival or large-scale maps require time-consuming, on-site manual updating while mapping bedrock and superficial geology. In contrast, stable ground conditions may have suitable legacy maps in some locations but not in others, such as where surveying is absent, incomplete or subject to legal restrictions. The geologist tasked with mapping may have to do this on short notice at their first site visit with no time to search for or create digital or physical copies of background maps on a suitable scale. The field mapper may encounter any of the above scenarios, especially the Geoforensic specialist tasked with Search and Rescue, hazard assessment or preparation and desktop study for subsequent search teams or law enforcement. Drone-derived orthoimagery and digital surface modelling can be conducted on-site in near real time to provide high resolution georeferenced maps for direct input of geological information, thus bypassing either non-existent or unsuitable base maps.

Ultrasonographic characteristics of neonatal appendicitis: a case series.

Neonatal appendicitis is a rare but critical condition that presents diagnostic challenges due to its nonspecific symptoms and clinical manifestations. Early and accurate diagnosis is crucial for reducing the high mortality rates associated with this condition. Abdominal ultrasonography plays a pivotal role in identifying characteristic signs of appendicitis in neonates. This study aimed to investigate whether neonatal appendicitis can be diagnosed with abdominal ultrasonography by identifying its specific signs. This study reviewed 20 consecutive cases of neonatal appendicitis confirmed through surgery at a National Medical Center. Preoperative abdominal ultrasonography was analyzed for direct and indirect signs of appendicitis. Our study included neonates with a mean age of 13.0 ± 7.1 days. The appendix was identifiable in 13 out of 20 cases (65%). The mean outer diameter of the appendix was 4.6 ± 1.8mm. Eight cases had appendix diameter ≥ 4mm. Fluid accumulation within the appendiceal cavity was noted in 6 (30%) patients, and peri-appendiceal fluid accumulation was detected in 5 (25%) patients. Ultrasonography revealed appendiceal perforation in 12 out of 16 cases (75%). The indirect signs of neonatal appendicitis included right lower quadrant (RLQ) abscess, pneumoperitoneum, and thickening of the intestinal wall and mesentery in the RLQ. Most cases of neonatal appendicitis may be diagnosed through abdominal ultrasonography by identifying both direct and indirect signs. Future studies with larger patient cohorts are needed to improve ultrasonographic diagnosis of neonatal appendicitis.

Reflection phenomena of thermoelastic plane waves on a rigid surface within a size-dependent elastic media

The current investigation aims to comprehend the spread of time-harmonic thermoelastic plane waves in an isotropic and homogeneous nonlocal elastic material without bounds, within the framework of the Lord–Shulman model and Eringen’s nonlocal stress model. Our analysis reveals two sets of coupled longitudinal waves and one independent shear-type wave. The coupled longitudinal waves experience dispersion and damping over time due to the dissipative nature of the L-S model. In contrast, the vertically shear-type waves exhibit dispersion characteristics due to the presence of nonlocality in the medium. Furthermore, we observe that the shear-type wave encounters a critical frequency, while the coupled longitudinal waves may face critical frequency conditions under certain circumstances. We explore the reflection of thermoelastic waves at a rigid, thermally insulated, and isothermal boundary of a thermoelastic half-space, particularly in the case of an incident coupled longitudinal thermoelastic wave. We determine the amplitude ratios of the reflected waves to the incident wave through analytical methods. For a specific model, we generate various graphs to analyze the behavior of phase speeds, attenuation coefficients, and reflection coefficients. To assess the impact of the elastic nonlocal parameter on the variations of phase speeds, attenuation coefficients, and amplitude ratios of the reflected waves, we present graphical representations. Notably, our observations indicate that all waves are influenced by the nonlocality of the medium. Longitudinal waves exhibit sensitivity to thermal parameters, whereas the shear-type wave remains independent of thermal effects. Furthermore, the presence of elastic nonlocality results in a reduction in the classical shear-type wave speed.

ACUTE TESTICULAR ISCHEMIA CAUSED BY INGUINAL HERNIATION WITH INCARCERATED LOOP OF SIGMOID COLON IN NEWBORN

The authors report a clinical case of a 14-day-old newborn with a left inguinal hernia with incarceration of the sigmoid loop associated with testicular ischemia, a clinical situation that posed some problems of diff erential diagnosis. The mother of the child was referred to the emergency department. Objective examination revealed hyperemia and edema of the left hemiscrotum, and on palpation there was a hard, irreducible, painful swelling. The child was urgently taken to surgery. On re-examination an incarcerated hernia was found with a viable sigmoid loop with moderate edematous changes. The testis showed obvious ischemic changes. With diffi culty, the sigmoid colon was reduced into the abdominal cavity, after observing the restoration of vascularization of the preserved testis. The postoperative result was positive and the child was discharged in satisfactory condition.

Investigation of geometric structure on energy performance and flow characteristics in underwater hydraulic machinery

PurposeFor underwater hydraulic machinery, the unique structure significantly enhances the three-dimensional non-uniformity of turbulence within the flow domain and high Reynolds number turbulence introduces complex effects on the machinery. Therefore, studying the turbulent flow characteristics in underwater hydraulic machinery is crucial for system stability.Design/methodology/approachThis paper conducts a numerical analysis on a specific type of underwater hydraulic machinery. A numerical calculation model is established under stable inflow conditions to analyze the flow trends and pressure changes at different flow speeds. Subsequently, structural modifications are made to the underwater hydraulic machinery, and the characteristics of the velocity field, pressure field and vorticity distribution under different model parameters are analyzed.FindingsThe results indicate that changes in internal structure have a certain impact on flow characteristics. When the structural changes are significant, the fluid flow becomes more complex and pressure fluctuations become more intense. The research findings provide a scientific basis and theoretical guidance for the structural design of underwater hydraulic machinery and have significant research implications for controlling fluid-induced noise.Originality/valueAffected by the inherent structural characteristics of the flow channel structure, the flow direction of the high-speed water flow changes drastically in the flow channel, so it is of great significance to study its flow characteristics for the stability of the system.

Stability and l∞ Performance Analysis for Nabla Discrete Fractional Linear Positive System with Time-Varying Delays

In this paper, the stability and l∞-gain problem are investigated for the Nabla discrete fractional linear positive systems with bounded time-varying delays. First, a sufficient condition and a necessary condition are presented to ensure the system’s positivity. Then, based on the system’s positivity property, an asymptotically stable condition is established. Furthermore, it is demonstrated that the l∞-gain of such systems is determined by the system matrices and is independent of the magnitude of delays. Finally, numerical examples are provided to demonstrate the validity of the obtained results.

Abstract 4120670: Pericoronary Adipose Tissue Inflammation as a Marker of Increased Coronary Plaque Burden in Patients With Chronic Coronary Artery Disease With Zero Calcium Score

Background: Dysfunctional or excess adiposity plays pivotal role in the development of coronary atherosclerosis. It remains unclear whether pericoroanry adipose tissue (PCAT) inflammation is associated with increased coronary plaque burden in its early stage of atherosclerosis, independent of traditional coronary risks or cardiovascular-kidney metabolic health. Purpose: To investigate the association of PCAT inflammation with coronary plaque burden in patients with newly suspected with chronic coronary artery disease (CAD) and zero calcium score who underwent coronary computed tomography angiography (CCTA). Methods: This retrospective CCTA study consists of 294 chronic CAD patients with zero calcium score (59 years, male 51 %). Chronic CAD was defined as stable condition with presence of increased non-calcified plaque burden on CCTA (Figure 1A-D). PCAT attenuation (PCATA) was assessed by fat attenuation index in the major three coronary arteries (right coronary artery, RCA; left anterior descending artery; LAD, and left circumflex coronary artery, LCX)(Figure 1C and D). Multivariable analysis using linear regression model was performed to determine independent predictors of increased %PV by adjusting for traditional coronary risks, metabolic risks, and chronic kidney disease (CKD). Hisayama Risk Score (HRS) was calculated to estimate 10-year cardiovascular risks. Results: Mean %plaque volume (PV) and PCATA-RCA was 44±4.0％ and -77±8.8 HU. %PV was correlated with age (p<0.05), systolic blood pressure (p<0.05), non-HDL cholesterol (p<0.05), Hisayama risk score (p<0.05, Figure 2), PCATA-RCA (p<0.001, Figure 3), PCATA-LAD (p<0.001), and LCX-PCATA (p<0.001). In a multivariable linear regression model adjusting for age, sex, hypertension, diabetes, dyslipidemia, and current smoking (model 1), PCATA-RCA was independently associated with %PV [beta, 0.17; 95% confidential interval (CI) 0.115-0.217, p < 0.001]. In a model adjusting for age, sex, metabolic syndrome, body mass index ≥23kg/mm 2 , and CKD (model 2), PCATA-RCA (beta, 0.18; 95% CI 0.128-0.232, p<0.001) and high-risk HRS (beta, 3.1; 95% CI 1.35−4.87, p<0.001) were independently associated with %PV. Similarly, independent associations of PCATA in LAD and LCX with %PV was observed. Conclusion: This study demonstrates that PCATA is a robust marker related to increased burden of coronary atherosclerosis even in the early stage of atherosclerosis as defined by zero coronary artery calcium score.

Abstract 4148073: Expect the Unexpected: Type A Aortic Dissection in Pregnant Patient with Marfan Syndrome

Case Description: A 26 yo woman with Marfan Syndrome (MFS, FBN1 ), ectopia lentis, aortic dilation and no family history of MFS or aortic dissection was evaluated for preconception counseling. She was asymptomatic, and the size of her aortic root (~4cm) and ascending aorta (~3.5cm) had been stable for over 5 years. She was counseled that risk of cardiac events during her pregnancy is high, but lower compared to those with aortic sizes >4.5cm. Once pregnant, she was followed closely with imaging every trimester (MRA at 25 weeks gestation showed stable aortic sizes). Cardio-obstetric recommendations included: CARPREG II score: 2, mWHO class: III, consideration of assisted second stage due to aortic root dilation. She was counseled on symptoms of aortic dissection and to seek emergency care should those symptoms arise. At 27 weeks gestation, she presented to the ED with intense chest and neck pain, shortness of breath, and headache. Emergent CT showed aortic root (4.1cm) and proximal ascending aortic dissection with propagation into the left main coronary artery (Figure 1). She underwent emergent C-section followed by aortic root and ascending aorta replacement and mechanical aortic valve replacement due to severe regurgitation. She was discharged in stable condition 8 days after an uncomplicated post-operative recovery. Her baby is recovering in the NICU. Discussion: While risk of aortic dissection in women with MFS is higher during pregnancy, recent studies suggest relative safety with aortic root diameters up to 4.5cm. Our case highlights that even at “lower risk” aortic sizes, aortic dissection remains an important risk for such women. Educating patients and providers about the acute symptoms of aortic dissection and forming an action plan for timely intervention can be lifesaving. Furthermore, some genetic mutations (e.g. TGBR1/2 or SMAD3 ) and sequence variants within the FBN1 gene may pose a higher risk of aortic dissection at smaller aortic diameters. Our patient’s pathogenic FBN1 mutation (-c.2114-5T>G, previously classified as a VUS) highlights the importance of genetic testing: prophylactic surgery at sizes <4.5cm may be considered with high-risk genetic variants or a family history of aortic dissection.

The Development of Machine Learning Models for Radial Compressor Monitoring With Instability Detection

Abstract Modern radial compressors are designed to operate with high performance and a wide range of applications while minimizing their environmental impact. It is necessary to study the machine near the stability limit and gain a comprehensive understanding of the fluid dynamic mechanisms that trigger the instability in the system to extend the operating range at high efficiency. Machine learning aids in developing pattern identification models for detecting compressor instability. In a prior study, a two-stage radial compressor for refrigerant gas underwent extensive simulation, capturing unsteady RANS conditions and generating a substantial dataset of pressure signals from multiple probes. Selected signals, coupled with detailed computational fluid dynamics (CFD) post-processing, revealed fluid dynamic structures near surge conditions. This study utilizes all pressure signals to assess the stage's operational state (stable, transient, or unstable/surge). An additional goal is to develop an algorithm predicting flow patterns in different stage sections with minimal pressure signals at the rotor inlet. This is a preliminary step toward the development of a smart monitoring and diagnostic model for the compressor installed in a plant. The developed model consists of three submodels, trained with CFD results obtained from unsteady Reynolds averaged Navier–Stokes (URANS) simulations. The three submodels are a regression submodule, a classification submodule, and a forecasting algorithm. The regression submodule predicts diffuser static pressure fields, the classification submodule categorizes whether the compressor is in a critical condition or not, and the forecasting algorithm predicts the inducer pressure signals in the future impeller rotations according to the actual operation history. These sub-modules work together to forecast whether the compressor, according to the operation strategy, is going into instability conditions.

Levosimendan, a Promising Pharmacotherapy in Cardiogenic Shock: A Comprehensive Review

Cardiogenic shock (CS) is a critical condition with high mortality rate, as the current management of CS presents significant challenges. Exploration of more effective therapies is necessitated. This review article comprehensively examines the efficacy and safety of levosimendan in the management of CS. By synthesising evidence from numerous studies, a comparison of levosimendan over traditional inotropic agents, such as enoximone, dobutamine, dopamine and norepinephrine, is highlighted. The unique mechanism of action of levosimendan enhances myocardial contractility without increasing oxygen demand, offering a promising alternative for patients with CS. This review also delves into comparative studies that demonstrate the superiority of levosimendan in improving survival rates, haemodynamic parameters, and reducing the incidence of CS complications. Safety profiles and adverse effects are critically assessed to provide a balanced view of the therapeutic window provided by levosimendan. The review concludes that levosimendan is a valuable addition to the therapeutic strategy against CS, with the potential to improve patient outcomes.

Abstract Su601: Missed Hypoxia in the Prehospital Care of Major Traumatic Brain Injury: Discrepancies Between Continuous Monitor Data and Clinical Documentation

Background: It is well established that prehospital hypoxia dramatically increases mortality in Traumatic Brain Injury (TBI). Thus, in EMS TBI research, case ascertainment and risk adjustment are highly dependent upon documentation of in-field O 2 saturation (SpO 2 ). Objective: To compare the rate of hypoxia identified by EMS personnel and documented in EMS patient care records (PCR) versus the actual rate of hypoxia recorded by continuous, non-invasive monitoring in TBI. Methods: A subset of major TBI cases (moderate/severe) from 5 EMS agencies reporting monitor data (Philips MRx™) in the EPIC EMS TBI Study (NIH 1R01NS071049) were evaluated (02/13-02/18). All monitor data available for post-hoc review were displayed and accessible to the providers during EMS care. We compared PCR documentation of hypoxia (SpO 2 <90%) to continuous monitor data in TBI patients (nasal canula O 2 , mask, basic or advanced airway). Statistic: exact McNemar’s test, α=0.05. Results: 120 cases were included [med. age 50; IQR (23.8, 68); 65% male. Monitors recorded 44 hypoxic cases (36.7%; 95%CI 28.1, 45.9%). Only 8 (6.7%; 2.9, 12.7%) were documented in the PCR (p<0.0001; Figure). Three machine-detected hypoxia cases had no PCR-documented SpO 2 at all. Conclusions: The difference in PCR-documented and monitor-identified hypoxia was dramatic. The monitor data revealed a five-fold greater incidence of hypoxia than that documented by EMS providers. This may be partially explained by the continuous nature of pulse oximetry in the face of ongoing care responsibilities and scene distractions. The field environment may cause providers to miss low readings as they fluctuate moment-by-moment. These findings have major clinical implications. While some of the discrepancy between PCR reporting and monitor data might simply be failure to document hypoxia, the much more concerning implication is that many cases might be unrecognized and untreated. Furthermore, these findings have important implications for case ascertainment, confounding, and risk-adjustment in EMS TBI research. Whenever possible, quality improvement and research projects should utilize continuous non-invasive monitor data to identify and evaluate hypoxic patients in the setting of TBI. These findings may also have implications for identifying hypoxia in EMS patients with other critical conditions.

Improving Freight Train Wheel Monitoring with Smart Sensors

Onboard monitoring of freight car axleboxes enhances safety, reduces maintenance costs, and improves track conditions by preventing secondary damage. Installing wireless sensors on freight cars without a nearby power source should be cost-effective, given the large quantities involved. To address this, a new wireless smart sensor node has been deployed. The sensor automatically recognizes stable operating conditions, detects wheel rotational speed from vibrations, performs real-time condition monitoring, and transmits the results to the cloud. This study outlines the smart sensor concept and the pilot field test conducted with real freight cars. The results demonstrate the ability to estimate wheel rotational speed from vibrations and the potential for detecting wheel out-of-roundness (OOR) using a newly developed condition indicator for low-power real-time operations.

Enhanced tribological properties of sliding contacts through the synergistic effect of PTFE film and PSAIL 2280

Purpose The purpose of this study is to investigate the effectiveness of a composite lubrication system combining polytetrafluoroethylene (PTFE) film and oil lubrication in steel–steel friction pairs. Design/methodology/approach A PTFE layer was sintered on the surface of a steel disk, and a lubricant with additives was applied to the surface of the steel disk. A friction and wear tester was used to evaluate the tribological properties and insulation capacity. Fourier transform infrared spectrometer was used to analyze the changes in the composition of the lubricant, and X-ray photoelectron spectroscopy was used to analyze the chemical composition of the worn surface. Findings It was found that incorporating the PTFE film with PSAIL 2280 significantly enhanced both the friction reduction and insulation capabilities at the electrical contact interface during sliding. The system consistently achieved ultra-low friction coefficients (COF < 0.01) under loads of 2–4 N and elucidated the underlying lubrication mechanisms. Originality/value This work not only confirm the potential of PTFE films in insulating electrical contact lubrication but also offer a viable approach for maintaining efficient and stable low-friction wear conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0222/