Aluminum Dust Explosion Research Articles

Visualization of aluminum dust flame propagation in a square-section tube

Metallic dust explosion is a challenging research topic. One key point of investigation is the flame propagation velocity, which can be determined experimentally by direct visualization of the explosions. This paper presents the results of flame propagation during an aluminum dust explosion inside a vertical prototype of 700 mm height and 150x150 mm square cross section, with glass walls. The study considers direct visualization: the light emitted by the aluminum flame is recorded with a fast camera. Aluminum flames look white and highly luminous. A special attention is therefore requested to collect images without saturation. Indeed, aluminum flame images from literature are mostly saturated; therefore comparison of images obtained with and without saturation is of high interest. The flame propagation velocity, which corresponds to the flame speed in the laboratory referential, is determined from saturated and non-saturated images. The burning velocity, i.e. the consumption rate of the reactants by the flame front, is then presented. With saturated images, the flame surface area is under-estimated, around 10-20 %, yielding to over-estimated burning velocity.

Analysis on clinical characteristics of 13 extremely severe burn patients complicated with severe inhalation injury in August 2nd Kunshan factory aluminum dust explosion accident

Objective: To investigate the clinical characteristics of extremely severe burn patients complicated with severe inhalation injury caused by dust explosion. Methods: The medical records of 13 extremely severe burn patients complicated with severe inhalation injury in August 2nd Kunshan factory aluminum dust explosion accident, who were admitted to the First Affiliated Hospital of Soochow University on August 2nd, 2014, were retrospectively analyzed. The following indicators were collected: (1) Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) score and Sequential Organ Failure Assessment (SOFA) score at post admission hour (PAH) 24. (2) Prognosis, death time, causes of death, and the mortality of patients with different sexes. (3) The number of times of airway electronic bronchoscopy, airway characteristics, and the corresponding onset time. (4) The number and result of microorganism culture of lesion tissue during the leukoplakia formation stage. Detection of Pseudomonas aeruginosa in patients with and without leukoplakia in airway mucosa. Fisher's exact probability test was used to detect the mortality of patients with different sexes. Kappa test was used to detect the relevancy between leukoplakia and Pseudomonas aeruginosa. Results: (1) The APACHE Ⅱ score of patients of this group at PAH 24 was (19±3) points, and the SOFA score was (12±3) points. (2) Eight patients survived, while 5 patients died, and the time of death was 19-46 (34±10) d after injury. The main cause of death was multiple organ dysfunction syndrome, which was secondary to severe infection. One of the 7 male patients and 4 of the 6 female patients died, but there was no significantly statistical difference in mortality between patients of the two sexes (P>0.05). (3) Airway electronic bronchoscopy was performed 4-25 (10±5) times among patients of this group. Hyperemia and edema were found in the airway mucosa of all the 13 patients 2-3 weeks after injury; ulcer was found in the airway mucosa of 5 patients 2-4 weeks after injury; leukoplakia was found in the airway mucosa of 7 patients 4-14 weeks after injury; granulation formed in the airway mucosa of 7 patients 10-15 weeks after injury, and airway patency was affected, which was solved after local clamping or replacement of lengthened tracheal cannula. (4) During the leukoplakia formation stage, 19 cases of microorganism culture were performed basing on airway lesion tissue, and the results were 15 cases of Pseudomonas aeruginosa, 5 cases of Acinetobacter baumannii, 2 cases of Serratia marcescens, as well as 1 case of Stenotrophomonas maltophilia, Burkholderia cepacia, and Proteus mirabilis each. Among 7 patients with airway mucosa leukoplakia, 6 patients were detected with Pseudomonas aeruginosa. Among 6 patients without airway mucosa leukoplakia, 1 patient was detected with Pseudomonas aeruginosa. The appearance of leukoplakia was consistent with the detection of Pseudomonas aeruginosa (Kappa=0.69, P<0.05). Conclusions: Most of these extremely severe burn patients complicated with severe inhalation injury caused by dust explosion survived, and there was no significant gender difference in mortality. Electronic bronchoscopy showed that the early manifestations of airway mucosa were hyperemia and edema, followed by varying degrees of erosion, ulcer, leukoplakia, and granulation formation, etc. Leukoplakia may be relevant to Pseudomonas aeruginosa infection.

Analysis on treatment of extremely severe burn patients with severe inhalation injury in August 2nd Kunshan factory aluminum dust explosion accident

Objective: To summarize the measures and experience in diagnosis and treatment of extremely severe burn patients with severe inhalation injury in dust explosion accident. Methods: The medical records of 13 patients with extremely severe burn complicated with severe inhalation injury in August 2nd Kunshan factory aluminum dust explosion accident who were treated at the First Affiliated Hospital of Soochow University (hereinafter referred to as our hospital) on August 2nd, 2014, were retrospectively analyzed. All the patients were transferred to our hospital 3-8 hours after injury under the condition of inhalation of pure oxygen. Twelve patients underwent tracheotomy within 5 hours after admission, while 1 patient underwent tracheotomy before admission. All the patients were in ventilator-assisted respiration, with synchronized intermittent mandatory ventilation combined with positive end expiratory pressure. All the patients underwent thorax or limbs escharotomy on the second day after admission, so as to reduce the restrictive ventilatory dysfunction caused by the contraction of thorax eschar and the terminal circulation disorder caused by the contraction of limbs eschar. All the patients underwent electronic bronchoscopy within 48 hours after admission, airway secretion were cleared and airway lavage were carried out under electronic bronchoscope according to the patients' condition, and the sputum, lavage solution, pathological tissue were collected for microbiological culture. All the patients underwent chest X-ray examination on the second day after admission and reexamination as required. Patients were all treated with a combination of broad-spectrum antibiotics early after admission to control lung and systemic infection. One patient was treated with extracorporeal membrane oxygenation for acute respiratory distress syndrome 1 week after admission. Results: One patient suffered from cardiopulmonary arrest during tracheotomy, which recovered autonomous respiration and cardiac impulse after cardiopulmonary resuscitation. Three patients showed decreased pulse oxygen saturation (SpO(2)) within 48 hours after injury, and the SpO(2) returned to normal after sputum aspiration, scab removal and lavage under electronic bronchoscope. During the course of disease, bacteria were cultured from wound exudate of 7 patients, bacteremia occurred in 10 patients, and sputum microbiological culture results of 13 patients were positive. Eight of the 13 patients in this group survived, and 5 died. One patient died 19 days after injury, and 4 patients died 33-46 days after injury. The main cause of death was multiple organ dysfunction syndrome induced by severe septic shock eventually. Conclusions: For this batch of patients with extremely severe burn complicated with severe inhalation injury caused by dust explosion accident, the treatment and cure measures including early definite diagnosis and timely tracheotomy, the application of effective ventilation, the effective treatment of respiratory system complications, and rational use of antibiotics for the control of lung infection obtained quite good curative effect.

Inhibition evaluation of ABC powder in aluminum dust explosion.

To investigate the inhibition effect of ABC powder for 5 μm and 30 μm aluminum dust explosions, a standard 20 L spherical chamber was employed to determine the explosion severity of Al/ABC mixtures and the MIC (minimum inerting concentration) of ABC powder. Results showed that the MIC increased as the concentration of aluminum dust increased. Meanwhile, the MIC decreased with the declining particle diameter of ABC but increased with the reducing diameter of the aluminum particles. SEEP (suppressant enhanced explosion parameter) phenomenon was observed when the concentration of ABC powder was low. To reveal the enhancement mechanism of ABC powder, explosion severity of NH3 and Al/NH3 mixture was also determined. Results showed that the explosion severity of aluminum dust was significantly enhanced by adding NH3. Scanning electron microscopy showed that the particles of the explosion residues of Al/NH3 mixture and Al/ABC mixture were significantly larger than those of pure aluminum explosion residues. X-ray photoelectron spectroscopy revealed that the major explosion products of Al/NH3 mixture was Al2O3. Explosion products of Al/ABC mixture were mainly comprised of Al2O3 and P2O5. The inhibition mechanism of aluminum dust explosion by ABC powder was summarized systematically based on these results.

Analysis of effects of discipline cooperation on rescue and treatment of severe mass burn patients involved in August 2nd Kunshan factory aluminum dust explosion accident

Objective: To analyze effects of cooperation between physicians in department of burn surgery and department of intensive care medicine on rescue and treatment of severe mass burn patients involved in August 2nd Kunshan factory aluminum dust explosion accident. Methods: On August 2nd, 2014, 15 extremely severe burn patients involved in August 2nd Kunshan factory aluminum dust explosion accident were admitted to temporary burn treatment center established in Department of Critical Care Medicine of the Second Affiliated Hospital of Soochow University. The 15 patients were equally divided into 3 groups, with 5 patients in each group. Fifteen surgeons and 30 nurses from department of burn surgery and 15 physicians and 30 nurses from department of intensive care medicine from different hospitals in China were divided into 3 groups, with 5 physicians and 10 nurses from department of burn surgery and 5 physicians and 10 nurses from department of intensive care medicine in each group. Each group of physicians and nurses were responsible for treatment of 5 patients. Treatment of patients was leaded by surgeons from department of burn surgery, who were responsible for wound dealing and operation. Physicians from department of intensive care medicine were responsible for systemic treatment and adjustment of relevant equipment's parameters. Volume of fluid infusion and urine output in shock period, severe systemic complication during period of treatment, using time and kind of antibiotics, death in 1 month after admission, length of hospital stay, and survival of patients were monitored. Results: Volume of fluid infusion of 15 extremely severe burn patients within the first 24 hours post injury was 10 360-17 162 (12 998±1 811) mL, including (1.62±0.23) mL·% total body surface area (TBSA)(-1)·kg(-1) electrolyte and colloid and (2 850±232) mL glucose, with electrolyte and colloid ratio of (1.76±0.23)∶1.00. Volume of urine output within the first 24 hours post injury was (2 384±1 242) mL, with (99±52) mL in each hour. Volume of fluid infusion of 15 extremely severe burn patients within the second 24 hours post injury was 8 720-11 616 (9 406±1 277) mL, including (1.04±0.22) mL·%TBSA(-1)·kg(-1) electrolyte and colloid and (2 910±187) mL glucose, with electrolyte and colloid ratio of (1.53±0.31)∶1.00. Volume of urine output within the second 24 hours post injury of patients was (2 299±1 362) mL , with (108±61) mL in each hour. One patient had pulmonary infection, and 7 patients had fungal infection, and no patient had gut microbiota dysbiosis. Patients were treated with combined 2 kinds of antibiotics for 21-85 (50±16) d. No patient died within 1 month after admission. The length of hospital stay was 53-132 (98±44) d. Ten patients survived finally. Conclusions: After being treated by cooperation between physicians in department of burn surgery and department of intensive care medicine, severe mass burn patients involved in August 2nd Kunshan factory aluminum dust explosion accident had hemodynamic stability and could stably experience shock period, with less complication, shorter length of hospital stay, no death within 1 month after admission, more survived patients, which can provide reference for rescue and treatment of severe mass burn patients.

Experience of wound treatment on extremely severe mass burn patients involved in August 2nd Kunshan factory aluminum dust explosion accident

Objective: To explore experience of wound treatment of extremely severe mass burn patients involved in August 2nd Kunshan factory aluminum dust explosion accident. Methods: On August 2nd, 2014, 98 extremely severe burn mass patients involved in August 2nd Kunshan factory aluminum dust explosion accident were admitted to 20 hospitals in China. The patients with complete medical record were enrolled in the study and divided into microskin graft group with 56 patients and Meek skin graft group with 42 patients. Split-thickness skin in area of residual skin were resected to repair wounds of patients in microskin graft group and Meek skin graft group by microskin grafting and Meek miniature skin grafting, respectively. The residual wound size on 28 days post injury and wound infection after skin grafting of patients in the two groups, and position of donor site of all patients were retrospectively analyzed. Data were processed with t test and chi-square test. Results: The size of residual wound of patients in Meek skin graft group on 28 days post injury was (59±13)% total body surface area (TBSA), which was obviously smaller than that in microskin graft group [(70±14)%TBSA, t=4.379, P<0.05]. Twenty-nine patients in microskin graft group and 11 patients in Meek skin graft group suffered from obvious wound infection after skin grafting. Wounds of patients in two groups were repaired with residual skin around wound in head, trunk, groin, armpit, and uncommon donor sites of scrotum (4 patients), vola (10 patients), and toe or finger web (8 patients). Conclusions: Meek skin graft is the first choice for wound repair of extremely severe burn mass patients, with faster wound healing, less wound infection. Uncommon donor sites of scrotum, vola, and toe or finger web can also be used for wound repair in case of lack of skin.

Comparison of machine learning method and logistic regression model in prediction of acute kidney injury in severely burned patients

Objective: To build risk prediction models for acute kidney injury (AKI) in severely burned patients, and to compare the prediction performance of machine learning method and logistic regression model. Methods: The clinical data of 157 severely burned patients in August 2nd Kunshan factory aluminum dust explosion accident conforming to the inclusion criteria were collected. Patients suffering AKI within 90 days after admission were enrolled in group AKI, while the others were enrolled in non-AKI group. Single factor analysis was used to choose independent factors associated with AKI, including sex, age, admission time, features of basic injuries, initial score on admission, treatment condition, and mortality on post injury days 30, 60, and 90. Data were processed with Mann-Whitney U test, chi-square test, and Fisher's exact test. Variables with P<0.1 in single factor analysis and those with possible clinical significance were brought into the establishment of prediction model. Logistic regression and XGBoost machine learning algorithm were used to build the prediction model of AKI. The area under receiver operating characteristic curve (AUC) was calculated, and the sensitivity and specificity for optimal threshold value were also calculated for each model. Nonparametric resampling test was used to compare the significance of difference of AUC of the two models. Results: (1) Eighty-nine (56.7%) patients developed AKI within 90 days from admission. Compared with 68 patients in non-AKI group, 89 patients in group AKI were older (Z=-2.203, P<0.05), with larger total burn area and full-thickness burn area (Z=-5.200, -6.297, P<0.01), worse acute physical and chronic health evaluation (APACHE) Ⅱ score, abbreviated burn severity index score, and sequential organ failure assessment (SOFA) score on admission (Z=-7.485, -4.739, -4.590, P<0.01), higher occurrence rate of sepsis (χ(2)=33.087, P<0.01), higher rates of accepting tracheotomy, mechanical ventilation, and continuous renal replacement therapy (χ(2)=12.373, 17.201, 43.763, P<0.01), larger first excision area (Z=-2.191, P<0.05), and higher mortality on post injury days 30, 60, and 90 (χ(2)=7.483, 37.259, 45.533, P<0.01). There were no statistically significant differences in sex, open decompression, admission time, 24-hour fluid volume after admission, 48-hour fluid volume after admission, the first 24-hour urine volume, the second 24 hour urine volume, the first excision time, and inhalation injury (χ(2)=0.529, 3.318, Z=-1.746, -0.016, -1.199, -1.824, -0.625, -1.747, P>0.05). The rates of deep vein catheterization of patients in the two groups were both 100%. (2) There were twenty possible prediction variables for preliminary establishment of model according to the difference results of single factor analysis and clinical significance of variables. (3) The logistic regression prediction model had three variables: APACHE Ⅱ score [odds ratio (OR)=1.36, 95% confidence interval (CI)=1.20-1.53, P<0.001], sepsis (OR=2.63, 95% CI=0.90-7.66, P>0.05), and the first 24-hour urine volume (OR=0.71, 95% CI=0.50-1.01, P>0.05). The AUC of the logistic regression prediction model was 0.875 (95% CI=0.821-0.930), with the specificity and sensitivity of optimal threshold value 84.4% and 77.7%, respectively. (4) XGBoost machine learning model had seven main predictive variables: APACHE Ⅱ score, full-thickness burn area, 24-hour fluid volume after admission, sepsis, the first 24-hour urine volume, SOFA score, and 48-hour fluid volume after admission. The AUC of machine learning model was 0.920 (95% CI=0.879-0.962), higher than that of logistic regression model (P<0.001), with the specificity and sensitivity of optimal threshold value 89.7% and 82.0%, respectively. Conclusions: Sepsis and fluid resuscitation are two important predictive variables that can be intervened for AKI in severely burned patients. Machine learning method has a better performance and can provide more accurate prediction for individuals than logistic regression prediction model, and therefore has good clinical application prospect.

Effects of airway management team in the treatment of severely mass burn patients combined with inhalation injury

Objective: To explore and analyze the effects of airway management team (AMT) in the treatment of severely mass burn patients combined with inhalation injury. Methods: The clinical data of 58 severely burned patients combined with inhalation injury hospitalized in our unit from January 2012 to August 2014, conforming to the inclusion criteria, were retrospectively analyzed. According to whether airway management was implemented by AMT or not, patients hospitalized from January 2012 to July 2014 were divided into control group (n=27), while patients in Kunshan factory aluminum dust explosion accident hospitalized on 2nd August 2014 were divided into observation group (n=31). Patients in control group received regular airway nursing carried out by nurses on duty, while patients in observation group received specialized airway concentration nursing implemented by AMT. The concrete implementation included overall assessment of patients' airway, elaborate airway care, and controlled management of mechanical ventilation. Arterial blood gas indexes and oxygenation index of patients in the two groups on post injury day (PID) 1, 7, and 14 were compared. Sputum viscosity, ventilator-associated pneumonia (VAP) occurrence rate, and ventilation time of patients in the two groups in post injury week(s) 1, 2, and 3 after admission were monitored and recorded. Survival rates of patients in the two groups were compared. Data were processed with analysis of variance for repeated measurement, t test and Bonferroni correction, chi-square test, and Wilcoxon rank sum test. Results: (1) There were no statistically significant differences in pH value, arterial partial pressure of oxygen (PaO(2)), arterial partial pressure of carbon dioxide (PaCO(2)), arterial oxygen saturation (SaO(2)), and oxygenation index of patients in the two groups on PID 1 (t=0.595, -0.166, 1.518, -0.828, 0.458, P>0.05). The pH values of patients in observation group on PID 7 and 14 were 7.327±0.050 and 7.367±0.043, respectively, significantly better than those in control group (7.304±0.021 and 7.390±0.029, respectively, t=-2.385, 2.391, P<0.05). The PaO(2) values of patients in observation group on PID 7 and 14 were (95.1±6.7) and (106.3±7.8) mmHg (1 mmHg=0.133 kPa), respectively, significantly higher than those in control group [(91.6±5.7) and (102.0±8.3) mmHg, respectively, t=-2.109, -2.059, P<0.05]. The PaCO(2) values of patients in observation group on PID 7 and 14 were (41±4) and (40±4) mmHg, respectively, significantly lower than those in control group [(43±5) and (43±4) mmHg, respectively, t=2.220, 2.304, P<0.05]. The SaO(2) values of patients in observation group on PID 7 and 14 were 0.95±0.04 and 0.96±0.04, respectively, significantly higher than those in control group (0.93±0.05 and 0.94±0.05, respectively, t=-2.201, -2.016, P<0.05). The oxygenation indexes of patients in observation group on PID 7 and 14 were (286±18) and (329±20) mmHg, significantly higher than those in control group [(277±14) and (306±58) mmHg, respectively, t=-2.263, -2.022, P<0.05]. (2) Sputum viscosity of patients in observation group in post injury week(s) 1, 2, and 3 were superior to that in control group (Z=-2.096, -2.076, -2.033, P<0.05). (3) VAP occurrence rate of patients in observation group was lower than that in control group, and time of mechanical ventilation of patients in observation group was shorter than that in control group (χ(2)=4.244, t=2.425, P<0.05). (4) Survival rate of patients in observation group was higher than that in control group (χ(2)=4.244, P<0.05). Conclusions: The special intensive care of airway management by AMT can effectively improve the oxygenation status of severely burned patients combined with inhalation injury, alleviate the sputum viscosity, reduce the occurrence of VAP, and shorten the time of mechanical ventilation, thus benefits the treatment of severely mass burn patients combined with inhalation injury.

Changes of helper T lymphocytes 17 and regulatory T lymphocytes in peripheral blood of patients with extensive burn at early stage in August 2nd Kunshan factory aluminum dust explosion accident and the significance

Objective: To explore the changes of helper T lymphocytes 17 (Th17) and regulatory T lymphocytes (Tregs) in peripheral blood of patients with extensive burn at early stage in August 2nd aluminum dust explosion accident in Kunshan factory (hereinafter referred to as Kunshan explosion accident) and the significance. Methods: Twenty patients with extensive burn in Kunshan explosion accident admitted to our department of burns and plastic surgery were enrolled in burn group, and 10 healthy adult volunteers with no history of smoking were enrolled in healthy control group. Five mL of peripheral venous blood samples were collected from patients in burn group at admission (≤post injury hour 6, PIH 6) and PIH 24, and on post injury day (PID) 7, and from volunteers in healthy control group respectively. The percentages of CD64(+) T lymphocytes, human leukocyte antigen-DR positive (HLA-DR(+) ) T lymphocytes, CD3(+) CD8(-) Th17, and CD4(+) CD25(+) Tregs in peripheral blood T lymphocytes were determined by flow cytometer. Results: (1) The percentages of CD64(+) T lymphocytes in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24 [(2.35±0.32)% and (4.02±0.15)%] were higher than (0.67±0.11)% of healthy volunteers in healthy control group. The percentage of CD64(+) T lymphocytes in peripheral blood T lymphocytes of patients in burn group on PID 7 [(0.39±0.25)% ] was lower than that of healthy volunteers in healthy control group. The percentages of HLA-DR(+) T lymphocytes in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24 [(54±18)% and (72±17)%] were higher than (38±14)% of healthy volunteers in healthy control group. The percentage of HLA-DR(+) T lymphocytes in peripheral blood T lymphocytes of patients in burn group on PID 7 [(28±15)% ] was lower than that of healthy volunteers in healthy control group. (2) The percentages of CD3(+) CD8(-)Th17 in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24 [(4.21±0.46)% and (7.38±0.39)%] were higher than (0.98±0.09)% of healthy volunteers in healthy control group. The percentage of CD3(+) CD8(-)Th17 in peripheral blood T lymphocytes of patients in burn group on PID 7 [(0.81±0.05)% ] was lower than that of healthy volunteers in healthy control group. (3) The percentages of CD4(+) CD25(+) Tregs in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24, and on PID 7 [(1.78±0.26)%, (1.26±0.37)%, and (0.38±0.03)%] were lower than (3.24±0.52)% of healthy volunteers in healthy control group. Conclusions: The percentage of Th17 in peripheral blood T lymphocytes of patients with extensive burn at early stage in Kunshan explosion accident increased at first and then decreased compared with that of healthy volunteers, indicating that the patients' immune function increased first and then weakened. The percentages of Tregs in peripheral blood T lymphocytes at each time point were lower than the percentage of healthy volunteers, indicating that the patients' immunomodulation gradually weakened after extensive burns.

Challenges for rescue and treatment of mass burns: the experience of rescue and treatment for casualties in August 2nd Kunshan factory aluminum dust explosion accident

The Kunshan factory aluminum dust explosion accident in August 2nd, 2014 caused the largest number of serious burn casualties in China in the recent 30 years. With the support of the whole country and the multidisciplinary cooperation, 185 severely burned patients were rescued and treated at 20 hospitals in Jiangsu province and Shanghai with satisfactory results. The rescue and treatment of mass burn is a complicated and systematic project on account of its suddenness, uncertainty, and non-repeatability. The treatment of this explosion accident was reviewed in this paper to explore the treatment model and experience of multidisciplinary cooperation. It is worthy to ponder and explore how to face challenges and strive to improve the treatment level of mass burns.

Analysis on treatment of eight extremely severe burn patients in August 2nd Kunshan factory aluminum dust explosion accident

Objective: To summarize the measures and experience of treatment in mass extremely severe burn patients. Methods: The clinical data and treatment of 8 extremely severe burn patients in August 2 Kunshan factory aluminum dust explosion accident who were admitted in the 100th Hospital of PLA on August 2nd, 2014, were retrospectively analyzed. There were 4 males and 4 females, aging 22-45 (34±7) years, with total burn area of 55%-98% [(89±15)%] total body surface area (TBSA) and full-thickness burn area of 45%-97% [(80±21)%] TBSA. All the 8 patients were accompanied with severe shock, inhalation injury, and blast injury. According to the requirements of former PLA General Logistics Department and Nanjing Military Command, a treatment team was set up including a special medical unit and a special care unit, with Chai Jiake from the First Affiliated Hospital of PLA General Hospital as the team leader, Zheng Qingyi from the 175th Hospital of PLA (the Affiliated Dongnan Hospital of Xiamen University) as the deputy leader, the 100th Hospital of PLA as the treatment base, and burn care, respiratory, nephrology, nursing specialists from the First Affiliated Hospital of PLA General Hospital, and the burn care experts and nursing staff from the 180th Hospital of PLA, 118th Hospital of PLA, 98th Hospital of PLA, and 175th Hospital of PLA, and nurses from the 85th Hospital of PLA, 455th Hospital of PLA, 101th Hospital of PLA, 113th Hospital of PLA as team members. Treatment strategies were adopted as unified coordination by the superior, unified responsibility of team leader, division of labor and cooperation between team members, and multidisciplinary cooperation led by department of burns. With exception of one patient who received deep vein catheterization before admission, the other 7 patients were treated with deep vein catheterization 0.5 to 3.0 hours after admission to correct hypovolemic shock as soon as possible. Eight patients received tracheotomy, and 7 patients were treated with mechanical ventilation by ventilator in protective ventilation strategy with low tide volume and low volume pressure to assist breathing. Fiberoptic bronchoscopy was done one to three times for all the 8 patients to confirm airway injuries and healing status. Escharectomy and Meek dermatoplasty in the extremities of all the 8 patients were performed 3 to 6 days after injury for the first time. Escharectomy, microskin grafting, and covering of large pieces of allogeneic skin on the trunks of 4 patients were performed 11 to 16 days after injury for the second time. The broad-spectrum antibiotics were uniformly used at first time of anti-infective therapy, and then the antibiotics species were adjusted in time. The balance of internal environment was maintained and the visceral functions were protected. One special care unit was on responsibility of only one patient. Psychological intervention was performed on admission. The rehabilitative treatment was started at early stage and in company with the whole treatment. Results: Acute renal injury occurred in 5 patients within 36 hours after injury and their renal function was restored to normal 4 days after injury due to active adjustment of fluid resuscitation program. No pulmonary complications, such as severe pulmonary infection and ventilator-associated pneumonia, occurred in the survived patients. One of the 8 patients died, and the other 7 patients were cured successfully. The wounds were basically healed in 2 patients in 26 or 27 days by 2 or 3 times of operation, and in 5 patients by 4 or 5 times of operation. The basic wound healing time was 26-64 (48±15) days for all the 7 patients. Conclusions: Treatment strategies of unified coordination by the superior, unified responsibility of team leader, division of labor and cooperation between team members, and multidisciplinary cooperation led by department of burns are the bases to successful treatment. Correcting shock as soon as possible is the prerequisite and closing wound as soon as possible is the key to successful treatment. Comprehensive treatment measures, such as maintaining and regulating the function of viscera, improving the body immunity, and preventing and treating the complications, are the important components to successful treatment. It is emphasized that in the treatment of mass extremely severe burn patients, specialist burn treatment should always be in the dominant position, and other related disciplines may play a part in auxiliary function.

Reflection on rescue and treatment of mass burn patients involved in August 2nd Kunshan factory aluminum dust explosion accident

The treatment of mass burn patients is related to social stability, life saving, and disability reducing. It is also an important opportunity to accumulate, summarize, and improve clinical rescue and treatment experience. Aiming at August 2nd Kunshan factory aluminum dust explosion, this article reviews and summarizes experience and problems about rescue reserve, first-aid system, multidisciplinary cooperation, and integration of usual time and emergent time treatment, so as to propose corresponding strategies and provide reference for the treatment of mass burn patients and critically burned patients.

Study of hydrogen explosion control measures by using l-phenylalanine for aluminum wet dust removal systems.

Wet dust removal systems are an effective design for preventing aluminum dust explosion in the process of metal polishing. However, wet dust removal systems pose hydrogen fire and explosion risks because aluminum dust can react with water to produce hydrogen gas. According to previous studies, l-phenylalanine can be used to solve the corrosion problem of metal slabs. In this work, a hydrogen inhibition method was proposed to inhibit hydrogen production in wet dust removal systems by using l-phenylalanine. The hydrogen evolution curves of aluminum particles reacting with different concentrations of l-phenylalanine solutions obtained via hydrogen inhibition experiments revealed that when the concentration of l-phenylalanine solutions reached 20 g L−1, essentially no hydrogen gas was produced. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the aluminum particles before and after the reaction. This work shows that l-phenylalanine is a good inhibitor. The adsorption of l-phenylalanine on the aluminum particle surface obeys the Langmuir adsorption isotherm. Additionally, Fourier transform infrared (FTIR) analysis was conducted to explain the physicochemical mechanism of the l-phenylalanine inhibition of hydrogen production. l-Phenylalanine is an environmentally friendly inhibitor and hence can be used in wet dust removal systems for the treatment of aluminum dust, which can reduce the hydrogen fire and explosion risk.

A Pythagorean-Type Fuzzy Deep Denoising Autoencoder for Industrial Accident Early Warning

Early warning is crucial for preventing industrial accidents and mitigating damage, but current methods are often time-consuming, error-prone, and incompetent to deal with uncertainty. This paper presents a fuzzy deep neural network for early warning of industrial accidents, which equips the classical deep denoising autoencoder (DDAE) model with Pythagorean-type fuzzy parameters in order to enhance the model's representation ability and robustness. To efficiently train the fuzzy deep model, we propose a hybrid algorithm combining Hessian-free optimization and biogeography-based optimization metaheuristic to balance global search and local search. Experiments on datasets from several industrial zones in China show that the proposed Pythagorean-type fuzzy DDAE (PFDDAE) can achieve much higher accuracy of accident risk classification than the classical DDAE and the fuzzy DDAE using regular fuzzy parameters, and the proposed hybrid learning algorithm exhibits significant performance advantage over some other learning algorithms in training PFDDAE. In particular, a test on the 2014 Kunshan aluminum dust explosion accident shows that the deep learning model would be very likely to prevent the accident if it was adopted in advance.

Inhibition of aluminum dust explosion by NaHCO3 with different particle size distributions

NaHCO3 with three particle size distributions was employed to determine the minimum inerting concentration (MIC, g/m3) for the explosion of 5μm and 30μm aluminum dust in a standard 20L spherical chamber and thus examine the effect of particle size on the inhibition efficiency. Results showed that the MIC significantly increases as the aluminum particle size decreases from 30μm to 5μm. For 30μm aluminum, the MIC dramatically decreased with the reduction in the NaHCO3 particle size. By contrast, for 5μm aluminum, the MIC was nearly independent of the particle size of NaHCO3 in the range studied. Time-scale analysis indicated that the decomposition of NaHCO3 must be faster than the aluminum combustion reaction for effective chemical inhibition. Scanning electron microscopy showed that the particles of the explosion residues of a NaHCO3/Al mixture were considerably larger than those of pure aluminum explosion residues. A diameter ratio βmix was defined to evaluate the degree of incomplete reaction promoted by NaHCO3. The composition of the explosion products was analyzed by X-ray photoelectron spectroscopy, and the data revealed that Na2CO3 and Al2O3 are the major species of the products. An inhibition mechanism was proposed based on these results.

Effect of dust explosion suppression by sodium bicarbonate with different granulometric distribution

The inert powder of sodium bicarbonate with different particle size distribution in certain proportion was employed to study its suppressing effect on dust explosion and flame propagation. A certain proportion of combustible aluminum dust was mixed with different granular sodium bicarbonate powder with single-diameter particle or different granulometric distribution. The explosion experiment was performed in a vertical pipe experimental platform. The ionic current and flame propagation behavior and flame temperature were obtained to evaluate the inhibitory effects of inert powder on dust explosion flame. The experimental results showed that the sodium bicarbonate with different granulomertic distribution made suppression effect on the flame of aluminum dust explosion. The inert inhibition powder with different granulomertic distribution led to flame structure change and reduced the thickness of the preheat zone during flame propagation. Meanwhile, the flame propagation velocity and flame temperature were reduced. Furthermore, an optimum proportion of sodium bicarbonate was obtained for the best inhibition effect on the aluminum dust explosion. Results show that the suppression effect on the flame combustion reaction zone was the critical factor for dust explosion mitigation.

Explosion severity of micro-sized aluminum dust and its flame propagation properties in 20 L spherical vessel

Using 20L explosion vessel, the present research work reports some experimental results which elucidate the effects of dust concentration, particle size and specific surface areas on aluminum dust explosion severity. Dust flame propagation property and explosion products were analyzed systemically. Six kinds of aluminum powders with different size distributions were selected and specially prepared for explosion tests. Results show that explosion parameters present an increasing and then decreasing trend with dust concentrations. The optimum explosion concentrations for all the selected aluminum dusts are similarly equal to 500g/m3. Maximum explosion pressures would be quadratic correlated with the decreasing of particle size. However, (dP/dt)max would be exponentially increasing with particle size decreasing. Aluminum dust flame propagation speed would be increased and the combustion mechanism would be transited from diffusion-controlled mode to kinetically controlled mode with particles diameter decreasing. For the finer dust cloud (dS less than 10μm), dust flame propagation speed would be exponential increased with dust concentration. However, there is a power function relation between flame propagation speeds and dust concentration for the coarse aluminum dust cloud (dS larger than 10μm). At the experimental condition, flame propagation speed presents an exponentially decreased trend with the increasing of particle size. Explosion products obtained at different conditions present different apparent morphology. The higher explosion pressure, the finer explosion fragments and nano-scale spherical structure would be produced. For coarse aluminum particles, explosion products present fluffy flocculent structure. Furthermore, alumina produced under lower explosion pressure conditions are mainly γ-Al2O3 components. Under high explosion pressure condition (such as 0.56MPa), there are notable bulges corresponding to α-Al2O3 are produced. Present research results may have important significance for understanding the explosion mechanism of aluminum-air dust/air cloud.

Prognostic significance of serum procalcitonin in patients with extremely severe burn and sepsis

To analyze the changes in serum procalcitonin (PCT) in patients with extremely severe burn and sepsis, and to evaluate its clinical significance in the prognosis of patients. Thirteen patients with extremely severe burn and sepsis injured in the aluminum dust explosion accident, which occurred in Kunshan of Jiangsu province, were admitted to our unit on August 2nd, 2014. They were involved in this retrospective study and divided into death group (n=5) and survival group (n=8) according to the outcome. Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ score and Sequential Organ Failure Assessment (SOFA) score at post admission hour (PAH) 24 were compared among the patients between two groups. Serum level of PCT, serum level of C-reactive protein (CRP), white cell count, neutrophils, platelet count, level of aspartate transaminase (AST), level of prealbumin (PA), level of creatinine, level of urea nitrogen, and level of blood sodium were compared among the patients between two groups in post admission week (PAW) 1, 2, 3, and 4. Data were processed with Fisher's exact test, analysis of variance for repeated measurement, t test, and Mann-Whitney test. Receiver operating characteristic (ROC) curves of serum PCT values were plotted to evaluate the predictive value for death of 13 patients in PAW 3 and 4. The differences in APACHE Ⅱ score and SOFA score at PAH 24 and serum level of CRP, white cell count, level of AST, level of creatinine, level of urea nitrogen, and level of blood sodium from PAW 1 to 4 of the patients between two groups were not statistically significant (with t values from -1.164 to 0.587, Z values from -1.872 to -0.442, P values above 0.05). The serum levels of PCT in patients of death group in PAW 3 and 4 were respectively (15.8±14.9) and (13.6±5.6) ng/mL, which were significantly higher than those of survival group [(2.4±1.8) and (4.9±6.1) ng/mL, with Z values respectively -2.635 and -2.208, P<0.05 or P<0.01]. The serum levels of PCT of patients in death group and survival group in PAW 1 and 2 were close (with Z values respectively -0.732 and -1.025, P values above 0.05). Compared with those of survival group, neutrophils in PAW 4 was significantly increased (t=-3.690, P<0.01), the platelet count in PAW 4 was significantly decreased (t=4.858, P<0.01), and the level of PA in PAW 2 was significantly increased in patients of death group (t=-2.320, P<0.05). There were no statistically significant differences in neutrophils, platelet count, and the level of PA at the other time points of patients between death group and survival group (with t values from -1.562 to 1.904, P values above 0.05). The total areas under ROC curves of serum level of PCT for predicting death of 13 patients with extremely severe burn and sepsis in PAW 3 and 4 were respectively 0.938 and 0.906, and 7.45 ng/mL and 8.77 ng/mL were respectively chosen as the optimal threshold values, with sensitivity of 75.0% and 100.0% and specificity of 100.0% and 87.5%. Serum level of PCT in PAW 3 and 4 can be used as the vital prognostic indicators for patients with extremely severe burn and sepsis, and it can be considered as a guide for rational treatment in clinic.

Small magnitude explosion of aluminium powder in an abatement plant: A telling case

On the 16th June 2000, an aluminum dust deflagration occurred in a small factory in the north-west of Italy. The explosion took place in an aluminum dust collecting and abatement unit that served a surface polishing plant. The collecting unit was made up of several ducts that conveyed dust into a manifold, which was connected to a cyclone and a bag filter.The cost of the deflagration cost was six injured workers, and relevant damage to the plant machinery, the process building and to other surroundings buildings.Although aluminum dust explosions are well known and have been well documented in the literature, this case study can be considered interesting because of its complex dynamics, which started with a first weak explosion that then evolved into a more severe chain of explosions.This article has drawn upon the official documents written during the investigation and the technical reports prepared by a number of expert witnesses. The data collected during the investigation have made it possible to determine the causes and dynamics of the accident and to calculate the strength of the explosion, on the basis of the distribution of the damage and the launching distance of the fragments. The magnitude of the damage seems to indicate that the amount of dust that took part in the explosion corresponds to the dust that settled on the bag filters.

Risk-based optimal safety measure allocation for dust explosions

Optimal allocation of safety strategies in order to reduce threats of dust explosions is very challenging, particularly when all potential accident contributors and various safety measures are to be taken into account. In this paper, we have proposed a risk-based optimal allocation of safety measures while considering both available budget and acceptable residual risk. The methodology is based on a Bayesian network (BN) to model the risk of dust explosions, which in turn helps identify key contributing factors, assess performances of relative safety measures, and decide on those safety measures to most efficiently control the risks of dust explosions within a limited budget. The Bayesian network also facilitates the implementation of diagnostic analysis to determine vulnerable parts in the system to which special attention should be paid in safety measure allocation. The Net Risk Reduction Gain (NRRG) for each relevant safety measure is also used to simultaneously account for both the cost of a safety measure and the respective risk reduction. Accordingly, the risk-based optimal allocation of safety measures will be achieved by maximizing the sum of the NRRG of all relevant safety measures under limited budgets, which is regarded as a knapsack problem. We applied the methodology to the aluminum dust explosion that occurred at Hayes Lemmerz International, Huntington, Indiana, US in October 2003. The result shows the efficacy and applicability of the proposed methodology for optimal risk reduction within a limited budget.