Regional Burn Research Articles

Investigation of the interaction of the MILD regime with HiTAC and no-combustion regimes in combustion region diagrams

Investigation of the interaction of the MILD regime with HiTAC and no-combustion regimes in combustion region diagrams

Continuous peripheral nerve blocks for burn management: a retrospective study of outcomes and complications in 281 burn patients.

There is scarce literature regarding the use of continuous peripheral nerve blocks in acute burn patients, who may be at higher risk for catheter-related complications, including infection. We sought to describe our center's experience and infection rate with continuous perineural catheters in the setting of pain management for patients suffering from burns. A retrospective observational study was performed including all patients admitted to an American Burn Association-verified regional burn center between January 2018 and July 2023 who received a continuous peripheral nerve block for an acute burn injury. There were 281 patients in the study cohort who received 484 perineural catheters. The cohort was 52% men with a median age of 39 years (IQR 30-55). A catheter-associated infection, defined as a clinical diagnosis by the treating physicians requiring the need for treatment with antibiotics or surgical debridement, was identified in six perineural catheters (1.2%, 95% CI 0% to 2.2%) involving six different patients (2.1%, 95% CI 0% to 3.8%). The median total body surface area burned was 5% (IQR 2-9%) and 20% of patients had full-thickness burns. The most commonly used catheters were infraclavicular (49%), popliteal sciatic (29%), femoral (19%), and adductor canal (17%). One-third (33%) of patients did not require operating room debridement as the block provided sufficient analgesia for bedside debridement. The median duration of catheter use was 6 days (IQR 4-8). There were no documented cases of nerve injury or toxicity, vascular injury, or local anesthetic systemic toxicity. In our practice, continuous perineural catheters in the setting of acute burns are associated with an infection rate comparable to other surgical populations.

Pediatric Burn Care for Burn Injury: Outcomes by Timing of Referral Using a U.S. Single-Center Retrospective Cohort, 2005-2019.

Burn centers offer specialized care to pediatric patients with burn injuries. However, data about outcome in relation to timing of transfer are limited. We examined these timings and outcomes among burn-injured pediatric patients. Single-center, retrospective cohort study of U.S. national and international practice. Shriners ESO Trauma Burn Registry, 2005-2019. Patients 0-17 years old admitted to a pediatric burn center with 10-80% total body surface area (TBSA) burn between 2005 and 2019. None. The cohort of 761 patients was subcategorized according to timing of referral: early presentation (EP) (0-7 d), delayed presentation (DP) (8-60 d), and very delayed presentation (VDP) (> 60 d). Primary outcomes included hospital length of stay (LOS), ICU LOS, percent TBSA (%TBSA)/LOS ratio, mortality, and disposition. Dichotomous outcomes were analyzed using logistic regression and continuous outcomes were compared using median regression, both utilizing multivariable analysis adjusting for a priori confounders and presented as adjusted coefficients (ACs) with 95% CI. Delayed referral (DP and VDP) was associated with higher %TBSA burn and with fewer referrals from high-income countries. Compared with EP, VDP was associated with higher LOS/%TBSA (AC, 0.2 [0.01-0.4]). On univariate analysis, in comparison with EP, DP and VDP were associated with higher ICU (DP 16 [6-29]; VDP 8 [0-18]) and hospital LOS (DP 34 [21-55]; VDP 32 [18-58]). Overall, ten of 761 patients died (1.3%), and we found no association between timing of referral and mortality. Also, in 751 survivors, 635 patients (84.6%) were discharged home without home health, and we found no association with timing of referral on multivariable analysis. In this report, we have reviewed our single-center, international burn-injured pediatric cohort, operating in the United States (2005-2019). We find that referral with VDP as opposed to EP was associated with increased LOS/%TBSA.

The 2023 American Burn Association Research and Advocacy Summit: Our Roadmap.

Research is one of the American Burn Association's (ABA) strategic priorities. Advocacy is required not only to promote burn research, but also, the ABA's other strategic priorities (Prevention, Quality, and Education). The ABA convened a two-day Research and Advocacy (R&A) Summit in September 2023, to develop a roadmap for the organization's research and advocacy efforts. The in-person summit identified fourteen key R&A initiatives. A multidisciplinary workgroup then developed strategies to achieve each initiative. The initiatives and strategies were then approved by the ABA's Board of Trustees as our organization's roadmap for research and advocacy. The next task will be to implement the initiatives. This will require not only oversight from the ABA's Board of Trustees, but also, effort from and collaboration between several of the ABA's committees and panels, including the Burn Science Advisory panel (BSAP), the Research Committee, the Prevention Committee, The Governmental Affairs Committee, The Organization and Delivery of Burn care Committee, the Quality and Burn Registry Committee, the ad hoc Coding Committee, and the ABA's Central Office.

Fluid and burns in children: What we know and what we do not know-a retrospective analysis of the German Burn Registry from 2015 to 2022.

Very little is known about the role of administered resuscitation volumes for the outcome of pediatric severely burned patients. This study observed a tendency to a restricted resuscitation and its potential benefits in terms of length of hospital stay. • Fluid resuscitation is an important aspect of therapy in the acute phase of children with extensive burns. • The Parkland formula is routinely used formula for determining fluid requirements. • 86.5 % received less volume than determined by Parkland and a tendency to restricted resuscitation and its potential benefits in terms of length of stay was observed. • There is still considerable lack of clarity, and a strictly individualized protocol with the support of formulas is of crucial importance.

Seasonal changes in black carbon footprint on the Antarctic Peninsula due to rising shipborne tourism and forest fires.

Refractory black carbon (rBC) has great potential to increase melting when deposited on snow and ice surfaces. Previous studies attributed sources and impacts of rBC in the northern Antarctic Peninsula region by investigating long-range atmospheric transport from South Hemisphere biomass burning and industrial regions or by assessing impacts from local tourism and research activities. We used high-resolution measurements of refractory rBC in a firn core collected near the northern tip of the Antarctic Peninsula, as well as atmospheric rBC from Modern-Era Retrospective Analysis for Research and Applications, Version 2, satellite measurements, modeling, burned area data, and tourism statistics, to assess combined impacts of both long-range transported rBC and locally emitted rBC. Our findings suggest that tourism activities have a regional rather than local impact and the increase in rBC concentrations during late spring-summer, influenced by tourism activities and fires in the Southern Hemisphere, can enhance ice melt. This highlights the need for strategies to reduce local and distant rBC emissions.

Factors associated with delayed admission to the burn unit: A major burn center’s experience

BackgroundTimely admission to the burn unit is crucial. Ideal burn care requires prompt interventions such as wound and body temperature management, infection control, and fluid resuscitation to prevent complications like burn progression and infection. In this study, we identify specific factors and outcomes associated with delayed admission to a regional burn center. MethodsPatients admitted to a large urban burn center from January 2015 to December 2023 were retrospectively queried, with subsequent collection of demographic and outcome variables from chart review. Descriptive statistics, Welch’s t-tests of unequal variances, and Chi-square analysis were performed. Multiple logistic regression was performed to explore the association between delayed admission and ICU stay, ventilator requirements, and mortality. ResultsA total of 3137 patients were included in the study. Approximately 63.4 % of patients were admitted within 24 h, while 36.6 % had a significant delay in care of over 24 h after injury. Male patients were likely to experience delayed admission (39.0 vs. 31.8 %, p < 0.001). There was no significant difference in age between the two cohorts (38.6 vs. 39.7 years, p = 0.199). There was no significant difference in time to admission by racial background (p = 0.061). Total body surface area burned (TBSA) varied between the delayed and control cohorts (15.5±18.7 % vs. 8.2±12.9 %, p < 0.001). Patients who were single (p < 0.001) and lived alone (p = 0.011) were more likely to experience a delay in burn unit admission. Homelessness (p < 0.001), substance abuse disorder (p < 0.001), and uninsured status (p < 0.001) were also associated with delayed admission. In regression analysis when controlling for TBSA, delay in care was significantly associated with a greater requirement for ICU stay (p < 0.001) and mechanical ventilation (p = 0.021) but was not associated with increased mortality (p = 0.232). ConclusionSociodemographic variables such as homelessness, lack of social support, and substance abuse are associated with delayed burn unit admission. Knowledge of these factors can inform future interventions to improve outcomes for vulnerable patients, promoting better recovery and long-term outcomes after burn injury.

Zn Isotope Tracing Unveils Primary Anthropogenic Zn Sources in Glacial Cryoconite of the High Asian Mountains

AbstractZinc (Zn) exerts a significant influence on the global environment, terrestrial ecosystems, and human health. The application of Zn isotopes (δ66Zn) has been suggested as a potent tool for tracing environmental contamination. However, studies focusing on Zn isotope tracing within the cryosphere areas are notably limited. Here we present the first data set on Zn isotopes in glacial cryoconite, based on observations over a large regional scale in High Asian Mountains (including Tibetan Plateau (TP) and its surroundings of western China). The results showed that glacial cryoconite had a general heavy Zn isotopic signature in various TP locations, with δ66Zn values ranging from −0.22‰ to +0.87‰. Employing the MixSIAR model, the overall Zn contribution source to the cryoconite was mineral dust (36%) &gt; coal burning (33%) &gt; non‐exhaust traffic emissions (22%) &gt; industrial smelting (10%). We ascertained that anthropogenic sources account for the primary contribution (about 60%–73%) of Zn inputs in all glacial locations, with coal burning emerging as the foremost anthropogenic contributor (mean 33%). Anthropogenic Zn in various TP locations was primarily derived from Zn emissions resulting from coal combustion, though it is also predominantly influenced by industrial smelting source in cryoconite of the Tianshan Mountains. Our results aligned with coal combustion data from the energy inventory of western China, suggesting that regional coal burning likely represents the foremost source of atmospheric Zn pollutant emission and deposition in the High Asia mountain glaciers.

Evaluation of a National Sample of 16,671 Pediatric Burn Admissions: Identifying Predictors of Non-accidental Pediatric Burns

BackgroundBurn injuries remain one of the leading causes of injury and death in children. Studies have demonstrated a higher mortality for pediatric burns associated with non-accidental injury. Using data from a burn registry, our study aimed to discern potential factors associated with non-accidental burn injuries. MethodsWe utilized the American Burn Association database from 2016 to 2018, which collects data from over one hundred burn centers across the United States, to evaluate a large pediatric burn population. Patients aged ≤14 years were analyzed. The population was then divided into suspected non-accidental versus accidental burn injuries. A multivariable logistic regression model was utilized to evaluate for predictors of burn injuries. Additional models were used to assess the relationship between suspected non-accidental burn injury and mortality, intensive care unit (ICU) stay, and hospital length of stay. Results16,671 pediatric patients were included. Of those, 1228 (7.4%) patients suffered non-accidental burn injury. A majority of children who sustained non-accidental burn injury were younger, non-white, and sustained scald burns. The regression model demonstrated predictors for non-accidental burn injuries included younger age, Black race, chemical/corrosion burns, government insurance, and increased total body surface area (TBSA) burn. Overall mortality for the population was 0.5%. ConclusionThis evaluation of a national burn registry reveals differences in pediatric patients sustaining non-accidental burns compared to accidental burns. The findings in this study identify pediatric populations at risk for suspected non-accidental burn injuries which may assist in preparing the families for expectations after admission for a burn injury. Level of EvidenceIII.

Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures: Purification, combustion and NOx emission characteristics

To optimize secondary air nozzle structure in purifying burner, this study focused on the comparison of purification, combustion and NOx emission characteristics of pulverized coal preheated by a 30 kW purifying burner with coaxial and centrosymmetric structures. Centrosymmetric structure shifted the position of main burning region down in high-temperature reduction unit (HTRU), and the number of branches differently influenced the temperature in different regions with this structure. For reductive gas components, CO concentration with centrosymmetric structure was higher compared to coaxial structure, while the differences in H2 and CH4 concentrations were smaller. Centrosymmetric structure was more disadvantageous to improve physicochemical properties of pulverized coal compared to coaxial structure, and this structure with four branches further deteriorated its properties compared to two branches. In mild combustion unit (MCU), the temperature at top was lower with centrosymmetric structure, while was higher in the rest. Centrosymmetric structure more effectively reduced NOx emission compared to coaxial structure, but with slight sacrifice of combustion efficiency (η). Moreover, both two-branch and four-branch centrosymmetric structures realized ultra-low NOx emission (<50 mg·m–3) with high η of over 98.50%, and the former was more advantageous. With this optimal structure, η and NOx emission were 99.25% and 40.42 mg·m–3.

Biomass-burning sources control ambient particulate matter, but traffic and industrial sources control volatile organic compound (VOC) emissions and secondary-pollutant formation during extreme pollution events in Delhi

Abstract. Volatile organic compounds (VOCs) and particulate matter (PM) are major constituents of smog. Delhi experiences severe smog during the post-monsoon season, but a quantitative understanding of VOCs and PM sources is still lacking. Here, we conduct a source apportionment study for VOCs and PM using a recent (2022), high-quality dataset of 111 VOCs, PM2.5, and PM10 in a positive matrix factorization (PMF) model. Contrasts between clean monsoon air and polluted post-monsoon air, VOC source fingerprints, and molecular tracers enabled us to differentiate paddy residue burning from other biomass-burning sources, which had previously been impossible. Burning of fresh paddy residue, as well as residential heating and waste burning, contributed the most to observed PM10 levels (25 % and 23 %, respectively) and PM2.5 levels (23 % and 24 %, respectively), followed by heavy-duty vehicles fuelled by compressed natural gas (CNG), with a PM10 contribution of 15 % and a PM2.5 contribution of 11 %. For ambient VOCs, ozone formation potential, and secondary-organic-aerosol (SOA) formation potential, the top sources were petrol four-wheelers (20 %, 25 %, and 30 %, respectively), petrol two-wheelers (14 %, 12 %, and 20 %, respectively), industrial emissions (12 %, 14 %, and 15 %, respectively), solid-fuel-based cooking (10 %, 10 %, and 8 %, respectively), and road construction (8 %, 6 %, and 9 %, respectively). Emission inventories tended to overestimate residential biofuel emissions at least by a factor of 2 relative to the PMF output. The major source of PM pollution was regional biomass burning, while traffic and industries governed VOC emissions and secondary-pollutant formation. Our novel source apportionment method even quantitatively resolved similar biomass and fossil fuel sources, offering insights into both VOC and PM sources affecting extreme pollution events. This approach represents a notable advancement compared to current source apportionment approaches, and it could be of great relevance for future studies in other polluted cities and regions of the world with complex source mixtures.

A retrospective, single-center 4-year review of synthetic polyurethane matrix use in burns and other complex wounds

Here we describe the use of a synthetic polyurethane matrix in the setting of burns and other complex wounds in the largest United States case series to date. A retrospective review was conducted at a verified, regional burn center. All patients greater than 18 years of age who received this matrix between January 2019 and July 2023 were included. A total of 182 patients with 250 wounds were included in this study. Thirty-seven percent were smokers, 23.6 % had diabetes and 5.5 % had peripheral vascular disease. The majority were acute burn wounds (60 %), followed by trauma (24.4 %), chronic wounds (5.6 %), infection (4 %) and donor sites (2 %). Exposed structures included fat (54 %), muscle (30 %), bone (16 %) and tendon (14.4 %). Microbial colonization was present in 143 (57.2 %) of cases: 98 (39.2 %) pre-application and 89 (35.6 %) post application. The incidence of new microbial colonisation post-application was 25.6 %. Infection was present in 117 (46.8 %) cases, 49 (19.6 %) pre-matrix application, 44 (17.6 %) post-matrix application and 24 (9.6 %) pre and post application. Eighteen patients (10 %) died. Median length of stay was 27 days. Median time to matrix implantation was 10 days. Median time from matrix placement to skin grafting was 35 days. Where documented, there were 162 wounds (83.5 %) with > 95 % matrix survival and 136 wounds (82.4 %) with > 95 % skin graft survival even in the setting of adverse factors such as infection, diabetes, or nicotine use. This study demonstrates the robustness of this skin substitute to achieve successful reconstruction even in the setting of adverse patient or wound characteristics.

FP7.20 - Peri-orbital burns: A 5-Year Review of the Epidemiological Characteristics and Outcomes at a Regional Burns Centre in the UK 2019 – 2023

Abstract Background Burn injuries are a major cause of global morbidity. Despite being infrequent, peri-orbital and ocular burns can have significant implications on a patient’s vision and overall quality of life. In Northern Ireland, the current epidemiological landscape of peri-orbital burns is not clear. This study aimed at assessing the incidence of peri-orbital and ocular burns and the management outcomes of patients admitted at the regional burns unit in Northern Ireland 2019-2023. Methods Patients admitted to the regional burns unit in Northern Ireland between January 2019 and September 2023 with periorbital burns were identified from the burns unit electronic records, the burns unit database and hospital image database. Results Over 5 years, 100 patients with facial burns were treated, including 60 patients with eyelid burns. 71% were males and 29% were females with a mean age of 47 years. The mean burn size was 14% total body surface area. The burn depth varied; 55% superficial partial thickness, 22% mixed, 17% full thickness and 6% deep dermal. Majority of burns were flame burns 64%. In total, 7 patients sustained corneal burns, one patient responded to steroids, one underwent amniotic membrane grafting, one lost complete vision in both eyes, one had physical debridement and topical antimicrobials and three patients required periorbital reconstruction to maintain eye closure. Conclusion 60% of Facial burns were associated with eyelid burns, the majority of which were caused by flame burns and were managed conservatively with wound cleaning, physical debridement, and application of topical antimicrobials. Despite being rare, complete loss of vision was associated with mortality among our patients.

Assessing turbulence–flame interaction of thermo-diffusive lean premixed H2/air flames towards distributed burning regime

Simultaneous laser-induced fluorescence of OH radicals and particle image velocimetry, and quasi-simultaneous 1D Raman/Rayleigh and 2D Rayleigh scattering measurements are used to investigate the effects of Karlovitz number (by varying the equivalence ratio) and residence time (by varying the axial measurement location) on the internal flame structures of lean premixed hydrogen/air turbulent jet flames. The turbulent flow fields, instantaneous macroscopic flame structures, and thermochemical states of a set of lean premixed hydrogen/air turbulent flames with varying initial equivalence ratio of 0.3, 0.4, and 0.45 at a constant bulk velocity of 100m/s are discussed. With an increasing equivalence ratio, the Karlovitz number derived from the turbulent flow fields decreases rapidly from 7690 to 260 and 100, determined at a downstream location of x/D=7. At the highest Karlovitz number (i.e., the lowest equivalence ratio), a distributed burning is observed in the jet flame as turbulent transport dominates over molecular mixing, and the effects of differential diffusion and flame curvature are suppressed. With decreasing Karlovitz number, intense burning regions characterized by elevated local equivalence ratio, high water mole fraction, and super-adiabatic flame temperatures are observed in association with positive flame curvature. The same combustion diagnostics are applied to another lean premixed hydrogen/air turbulent flame with an initial equivalence ratio of 0.4 and a bulk velocity of 200m/s at selected downstream locations of x/D=3.5, 7, 10.5, and 14 to assess the effects of developing turbulence and residence time. Corresponding Karlovitz numbers are 680, 730, 775, and 690, as the local turbulent intensity changes along downstream locations. While flame structures reveal characteristics towards distributed burning at lower x/D, a locally intense burning region appears at higher x/D together with positive curvature. This is mainly because the turbulence develops with increasing x/D and the flame surface is more disturbed and curved by turbulent eddies with increasing turbulence length scales. The highly diffusive hydrogen is locally concentrated by positively curved flame surfaces, resulting in fuel-rich burning regions at a higher temperature. This indicates that, as velocity fluctuations increase in axial direction, turbulence can also promote thermo-diffusive instabilities to a certain extent, increasing the mixture inhomogeneity in temperature space by interacting with the differential diffusion effect of hydrogen at atmospheric pressure.Novelty and significanceThe novelty of the current work is the focus on turbulence–chemistry interactions of premixed hydrogen/air jet flames at high turbulence and ultra lean conditions. Comprehensive experimental results including the turbulent flow fields (particle image velocimetry), instantaneous flame structures (laser-induced fluorescence of OH radicals) and internal thermochemical states (quasi-simultaneous 1D Raman/Rayleigh and 2D Rayleigh scattering imaging) of hydrogen/air jet flames are analyzed and discussed. The data sets with well-characterized boundary conditions and high measurement accuracy, are crucial for validation and development of numerical simulation models.

Unveiling Sex Differences in Pediatric Burns Through the World Health Organization (WHO) Global Burn Registry

IntroductionPediatric burns present a significant global health challenge, particularly in low- and middle-income countries (LMICs). Despite this burden, few studies have explored global sex-based differences in pediatric burns. This study aims to describe pediatric burn incidence, burn care facilities’ capacities, and burn outcomes with a focus on sex, comparing LMICs to HICs. MethodsThis study utilizes the World Health Organization's (WHO) Global Burn Registry (GBR) to analyze pediatric burn cases from 2018 to 2022, examining patient demographics, causes of burns, burn care facilities' capacities, and burn outcomes in relation to sex. Statistical analysis was done by chi-square and logistic regression. ResultsIt was found that female patients were less likely than males to undergo surgical treatment during their hospital stay in low-income countries (adjusted odd ratios = 0.86, 95% CI: 0.45–1.26; p = 0.168) and middle-income countries (adjusted odd ratios = 0.72, 95% Cl: 0.52–0.95; p = 0.002). Additionally, females in both low- (adjusted odd ratios = 2.23, 95% Cl: 1.12–3.53; p = 0.045) and middle-income countries (adjusted odd ratios = 1.72, 95% Cl: 1.12–2.95; p < 0.001) exhibited higher odds of discharging with disability compared to males. ConclusionSex-based differences persist in pediatric burn epidemiology and treatment outcomes. Addressing these differences involves sex-sensitive strategies to mitigate the burden of pediatric burns, particularly in vulnerable populations in low- and middle-income countries. Type of StudyRetrospective observational study. Level of EvidenceLevel III evidence.

Development of Risk Indicator Incorporating Regional Characteristics for Fire-Following Earthquake Risk Assessment

Secondary damages caused by earthquakes, such as fires, tsunamis, and landslides, significantly damage buildings (or structures) and adversely affect humans. Historical cases have highlighted the severe dangers posed by fire-following earthquakes (FFEs). The risk of FFE is determined by regional characteristics, such as the density of buildings and the types of fire-resistant structures. However, researchers have previously evaluated this risk by comparing relative fire burn rates without considering regional characteristics. Hence, a methodology used previously is adopted in this study to calculate regional-level fire burn rates in Pohang City. Subsequently, the relationship between regional characteristics and fire burn rates is examined. Based on the analysis results, a new risk indicator is proposed for evaluating the FFE risk while considering regional characteristics, and the results obtained for Pohang City are compared with those published in the literature (FFE risk ranking in L, Northern, Pohang = 3 or 2 vs. 2).

A Randomized Controlled Trial of Home-Based Virtual Rehabilitation to Improve Adherence to Prescribed Home Therapy after Burn Injury: A Northwest Regional Burn Model System Trial.

Daily rehabilitation after burn injury is vital for prevention of function-limiting contractures. However, adherence to prescribed therapy following acute burn hospitalization has historically been low and not well-studied. Studies involving virtual reality technology have demonstrated an association with improved functional outcomes in burn therapy. We conducted a five-year randomized controlled trial comparing 12 weeks of a home-based virtual rehabilitation (HBVR) system with standard burn therapy. Our primary outcome was adherence to prescribed home therapy, measured by e-diary self-report. Secondary outcomes included steps walked daily and patient-reported outcomes regarding stiffness, upper extremity function, and mobility. We enrolled 50 subjects, of which 48 provided data for analysis (23 HBVR, 25 control). Overall adherence to prescribed home therapy was low, 37.2% in the HBVR group and 60.0% in the control group. Reasons for non-adherence in the HBVR group included lack of time, engagement, and replacement of therapy with other physical activity. However, some subjects enjoyed HBVR and believed it aided their recovery. There was no difference in daily steps walked between the two groups. Daily walking gradually improved from 3,500 steps per day in the first week after baseline and plateaued at 6,000 steps per day at week five. There were no differences in stiffness, upper extremity function, and mobility between the two groups at baseline and 3-, 6-, and 12-month follow-up. Subjects demonstrated improved upper extremity function and mobility in the first year after discharge that coincided with increasing stiffness.

A full-scale experimental investigation of natural gas explosion in a 710-m long utility tunnel with multiple pipelines

Natural gas poses significant risks to the safe operation of utility tunnels, which house multiple critical infrastructure systems, including natural gas pipelines. To date, no full-scale gas explosion tests in utility tunnels have been published, and there is ongoing debate about whether pipelines can withstand such explosions. This study presents the first-ever 1:1-scale experiments conducted in a 710-meter-long tunnel with cross-sectional dimensions of 3.2 m × 2.6 m. Three pipelines, each approximately 25 m in length and constructed to industrial standards, were used to investigate potential damage. The experiments comprehensively captured the development of flow fields, including flame images, flame signals, temperature, and overpressure, as well as pipeline responses. Results revealed that variations in overpressure within the combustion region were driven by both positive and negative feedback loops. A significant pressure drop was also observed as airflow passed through a local expansion. The experiments further demonstrated that while pipelines within utility tunnels are unlikely to be directly damaged by gas explosions, accessories such as racks are at high risk of severe destruction. These findings offer essential insights for improving the safety design, construct, and operation of tunnel-like spaces involving flammable gases.

Epidemiological characteristics and outcomes of special-cause burns: analysis of 33,619 burn patients in a major regional burn center in China from 2004 to 2021

Special-cause burn injuries are usually more severe and difficult to manage, and often contribute to a high mortality in severely injured patients. The aim of this study was to present the epidemiological characteristics of special-cause burn in a major regional burn center in China between 2004 and 2021 and determine the risk factors associated with the mortality of burn patients. A total of 33,619 burn patients were included the study, among which 4,452 (13.2%) were special-cause burn patients. Compared to the thermal burn group, the special-cause burn patients were usually male, elder, married and III-IV degree of burn with onset of upper extremity in summer and autumn. Moreover, a greater proportion of patients in the special-cause burn group underwent surgical treatment and amputation and had a higher median hospital stay and treatment costs. During the multivariate logistic regression, older age, male, unmarried, winter, III-IV degree of burn, ≥ 3 burn sites, and larger total body surface area (TBSA) of burn were significantly associated with higher burn mortality (all P < 0.05), however, patients with special-cause burn injuries have not increased odds for mortality (P > 0.05). These results suggested that special cause-burn patients suffer more severe injuries, resulting in longer hospital stays and higher health care expenditures, but it did not significantly increase the mortality risk. Therefore, burn clinicians should not only have the responsibility to cure burns, but also need to know and popularize burn epidemiological characteristic and precaution.

NOx generation in marine dual-fuel engines: Effects of ammonia blending ratio and spark ignition timing

Ammonia application in marine engines can effectively mitigate greenhouse gas emissions. However, engines powered by ammonia produce considerably higher levels of NOx emissions compared to conventional fuel engines. In the present study, a combustion model for the marine dual-fuel engine fueled with natural gas and ammonia has been established using the CONVERGE software. The nitrogen element-tracking method is employed in the engine combustion simulation. This study aims to investigate the effects of ammonia blending ratio (XNH3 = 0% ∼ 50%) and spark ignition timing (SIT = −20 °CA ATDC ∼ −40 °CA ATDC) on the emission characteristics and spatiotemporal distribution of nitrogen-based pollutants under lean-burn and stoichiometric-burn conditions. The results indicate that as the XNH3 increases, total NOx emissions decrease at stoichiometric-burn conditions, while it initially increases and then decreases at lean-burn conditions, reaching a peak of 3760 ppm at XNH3 = 30%. Besides, fuel NO emissions are predominant at lean-burn conditions, whereas at stoichiometric-burn conditions, thermal N*O emissions are predominant. Additionally, as the SIT advances, total NOx emissions initially decrease and then remain unchanged, reaching a minimum at −35 °CA ATDC, and it gradually increases at lean-burn combustions. Furthermore, the spatial distribution of NO at CA50 illustrates that fuel NO is primarily concentrated at the flame front, while thermal N*O predominates in the high-temperature burned region. N2O is observed in the low-temperature region near the cylinder wall during the expansion stroke. Moreover, fuel NO is primarily produced by ammonia's decomposition with OH radicals. There are three dominant reactions for the formation of NO: HNO→NO, NH→NO, and N→NO. The coupling mechanism of carbon and nitrogen elements is achieved by H2CN and HCN radicals.