Journal Articles, Hindawi Press

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The Essential Oils Compounds of Lippia multiflora Moldenke and Cymbopogon schoenanthus (L.) Spreng Repel and Affect the Survival of the Maize Pest Spodoptera frugiperda (Lepidoptera: Noctuidae) Larvae
Wangrawa, Dimitri Wendgida; Waongo, Antoine; Traore, Fousséni; Sanou, Drissa; Lahondere, Chloé; Sané, Abdoul Razac; Borovsky, Dov; Ouédraogo, Sylvain Nafita; Sanon, Antoine (Hindawi, 2024-04-01)
Plant-derived insecticides, such as essential oils, can be an effective alternative to replace synthetic chemical insecticides against Spodoptera frugiperda, which becomes increasingly resistant to synthetic products. This study aims to evaluate essential oils (EOs) effects on larval growth and development following feeding inhibition, growth regulation, and repellency of EOs of Lippia multiflora (Verbenaceae), Cymbopogon schoenanthus (Poaceae), and their combination. Topical application of EOs was used on S. frugiperda larvae for larvicidal effect or treating filter paper with the EOs to find repellency. The effect of EOs on food intake and larval growth was also evaluated. Several types of compounds have been identified in the EOs, mainly monoterpenes with the appearance of new compounds in the 1 : 1 combination. Bioassay results show that individuals and combinations of EOs significantly influenced S. frugiperda larval development. L. multiflora caused 100% mortality of L2 larvae within 24 hours at 3%. The Lm + Cs (1 : 1) EOs combination was the most effective with LC50 and LC90 of 1.02% and 1.92%, respectively. Lm + Cs (1/4 : 3/4) EOs caused the highest inhibition of food consumption, 0.0160 g consumed after food was treated with 2.2% concentration compared to food consumption of 0.0602 g for the control group at 24 hours. Lower food consumption caused the inhibition of larval growth and weight loss of 0.0005 g/day at the 2.2% EOs concentration. The highest repellency effect of the EOs was found in EOs of L. multiflora, exhibiting a repulsion of 83.33% of the larvae after 3 hours of exposure. This diversity in the biological actions of the EOs tested on S. frugiperda represents valuable options for contributing to integrated pest management and an alternative to synthetic chemical insecticides.
Facial Emotion Recognition and Classification Using the Convolutional Neural Network-10 (CNN-10)
Dada, Emmanuel Gbenga; Oyewola, David Opeoluwa; Joseph, Stephen Bassi; Emebo, Onyeka; Oluwagbemi, Olugbenga Oluseun (Hindawi, 2023-10-13)
The importance of facial expressions in nonverbal communication is significant because they help better represent the inner emotions of individuals. Emotions can depict the state of health and internal wellbeing of individuals. Facial expression detection has been a hot research topic in the last couple of years. The motivation for applying the convolutional neural network-10 (CNN-10) model for facial expression recognition stems from its ability to detect spatial features, manage translation invariance, understand expressive feature representations, gather global context, and achieve scalability, adaptability, and interoperability with transfer learning methods. This model offers a powerful instrument for reliably detecting and comprehending facial expressions, supporting usage in recognition of emotions, interaction between humans and computers, cognitive computing, and other areas. Earlier studies have developed different deep learning architectures to offer solutions to the challenge of facial expression recognition. Many of these studies have good performance on datasets of images taken under controlled conditions, but they fall short on more difficult datasets with more image diversity and incomplete faces. This paper applied CNN-10 and ViT models for facial emotion classification. The performance of the proposed models was compared with that of VGG19 and INCEPTIONV3. The CNN-10 outperformed the other models on the CK + dataset with a 99.9% accuracy score, FER-2013 with an accuracy of 84.3%, and JAFFE with an accuracy of 95.4%.
Friend or Foe: Factor XII Deficiency Discovered Incidentally during Management of NSTEMI
Beck, Patrick J.; Benfield, John; Morales, Joshua (Hindawi, 2023-06-29)
Factor XII (FXII) deficiency is a rare coagulopathy that typically goes undiagnosed due to the lack of abnormal bleeding or thrombosis. However, the accompanying prolonged activated partial thromboplastin time (aPTT) can create difficulties with maintaining therapeutic anticoagulation in the setting of acute coronary syndrome (ACS). Here, we present the case of a 52-year-old man presenting with chest pain and diagnosed with an NSTEMI but also found with a prolonged baseline aPTT ultimately secondary to FXII deficiency. Here, we discuss the diagnostic work-up of an isolated prolonged aPTT to identify possible etiologies, such as FXII deficiency, and ultimately inform ACS management.
False-Positive Phencyclidine (PCP) Result on 11-Panel Urine Drug Screen (UDS) in a 17-Year-Old Adolescent with Long-Term Venlafaxine Use
Kim, Hyun Sue; Jain, Aakash; Kablinger, Anita S. (Hindawi, 2023-06-26)
Venlafaxine is an antidepressant belonging to the class of serotonin–norepinephrine reuptake inhibitors that are US Food and Drug Administration-approved to treat and manage symptoms of depression, anxiety, and other mood disorders in adults. We describe an adolescent patient who likely had a false-positive phencyclidine result detected with an 11-panel urine drug screen in an outpatient setting of long-term use of therapeutic venlafaxine extended release for the treatment of recurrent major depressive disorder and generalized anxiety disorder. We believe that this may be the first published case report to characterize this phenomenon in a young patient in the absence of an acute overdose.
Assessing Variation in the Individual-Level Impacts of a Multihost Pathogen
Lewin, Zachary M.; Astorga, Francisca; Escobar, Luis E.; Carver, Scott (Hindawi, 2023-05-27)
Most pathogens infect more than one host species, and given infection, the individual-level impact they have varies among host species. Nevertheless, variation in individual-level impacts of infection remains poorly characterised. Using the impactful and host-generalist ectoparasitic mite Sarcoptes scabiei (causing sarcoptic mange), we assessed individual-level variation in pathogen impacts by (1) compiling all documented individual-level impacts of S. scabiei across free-living host species, (2) quantifying and ranking S. scabiei impacts among host species, and (3) evaluating factors associated with S. scabiei impacts. We compiled individual-level impacts of S. scabiei infection from 77 host species, spanning 31 different impacts, and totalling 683 individual-level impact descriptions. The most common impacts were those affecting the skin, alopecia (130 descriptions), and hyperkeratosis coverage (106). From these impacts, a standardised metric was generated for each species (average impact score (AIS) with a 0-1 range), as a proxy of pathogen virulence allowing quantitative comparison of S. scabiei impacts among host species while accounting for the variation in the number and types of impacts assessed. The Japanese raccoon dog (Nyctereutes viverrinus) was found to be the most impacted host (AIS 0.899). We applied species inclusion criteria for ranking and found more well-studied species tended to be those impacted more by S. scabiei (26/27 species AIS ud_less_than 0.5). AIS had relatively weak relationships with predictor variables (methodological, phylogenetic, and geographic). There was a tendency for Diprotodontia, Artiodactyla, and Carnivora to be the most impacted taxa and for research to be focussed in developed regions of the world. This study is the first quantitative assessment of individual-level pathogen impacts of a multihost parasite. The proposed methodology can be applied to other multihost pathogens of public health, animal welfare, and conservation concern and enables further research to address likely causes of variation in pathogen virulence among host species.
Helicobacter Pylori-Negative MALT Lymphoma: A Series of Two Cases Presenting with Life-Threatening Upper Gastrointestinal Bleeding
Kim, Seo Hyun; Soliman, Youssef; Chitnavis, Vikas N.; Chitnavis, Maithili V. (Hindawi, 2023-03-23)
Mucosa-associated lymphoid tissue (MALT) lymphoma is a common cause of gastric lymphoma. Although most cases are associated with an H. pylori infection, approximately 10% are H. pylori-negative. Patients with gastric MALT lymphoma are usually asymptomatic or present with nonspecific symptoms such as abdominal pain, dyspepsia, weight loss, and occult gastrointestinal bleeding. In this report, we describe two patients with H. pylori-negative MALT lymphoma who both presented with acute upper gastrointestinal bleeding that led to hemodynamic instability. After resuscitation, emergent endoscopy was performed. Both patients had the t (11; 18) (q21; q21) translocation, which prompted direct treatment by radiotherapy.
Dysgerminoma Masquerading as Gestational Trophoblastic Neoplasia
Blackwell, Conner; McLeish, Shian; Iglesias, David; Armbruster, Shannon D. (Hindawi, 2023-02-08)
Background: Persistent elevation in beta-human chorionic gonadotropin (β-hCG) following a pregnancy is concerning for gestational trophoblastic neoplasia (GTN). However, the differential diagnosis should remain broad during the evaluation process. Case: A 34-year-old G3P3 presented with elevated β-hCG four months after cesarean delivery with bilateral tubal ligation. The patient was treated with methotrexate for a presumed new ectopic pregnancy. Due to persistent β-hCG elevation, she received actinomycin-D for GTN treatment. After completing chemotherapy, her β-hCG increased. The patient underwent a laparoscopic hysterectomy with unplanned left oophorectomy due to its nodular appearance at the time of surgery. Pathology confirmed a dysgerminoma of the ovary and benign uterus. Conclusion: Although dysgerminomas are uncommon, they should be considered when β-hCG levels remain elevated despite therapies for more common pathologies.
Association of Radial Artery Access with Reduced Incidence of Acute Kidney Injury
Kietrsunthorn, Patrick S.; Locklear, Tonja M.; Fonner, Clifford E.; Berzingi, Chalak O.; Foerst, Jason R.; Mirza, Mohd A.; Sane, David C.; Williams, Eric; Shor, Robert A.; Dehmer, Gregory J. (Hindawi, 2023-01-18)
Objectives. To determine if radial artery (RA) access compared with femoral artery (FA) access for percutaneous coronary intervention (PCI) is associated with a lower incidence of acute kidney injury (AKI). Background. AKI results in substantial morbidity and cost following PCI. Prior studies comparing the occurrence of AKI associated with radial artery (RA) versus femoral artery (FA) access have mixed results. Methods. Using a large state-wide database, 14,077 patients (8,539 with RA and 5,538 patents with FA access) were retrospectively compared to assess the occurrence of AKI following PCI. To reduce selection bias and balance clinical data across the two groups, a novel machine learning method called a Generalized Boosted Model was conducted on the arterial access site generating a weighted propensity score for each variable. A logistic regression analysis was then performed on the occurrence of AKI following PCI using the weighted propensity scores from the Generalized Boosted Model. Results. As shown in other studies, multiple variables were associated with an increase in AKI after PCI. Only RA access (OR 0.82; 95% CI 0.74–0.91) and male gender (OR 0.80; 95% CI 0.72–0.89) were associated with a lower occurrence of AKI. Based on the calculated Mehran scores, patients were stratified into groups with an increasing risk of AKI. RA access was consistently found to have a lower risk of AKI compared with FA access across these groups of increasing risk. Conclusions. Compared with FA access, RA access is associated with an 18% lower rate of AKI following PCI. This effect was observed among different levels of risk for developing AKI. Although developed from a retrospective analysis, this study supports the use of RA access when technically possible in a diverse group of patients.
Adaptive Control of the Atmospheric Plasma Spray Process for Functionally Graded Thermal Barrier Coatings
Guduri, Balachandar; Batra, Romesh C. (Hindawi, 2022-11-23)
Functionally graded coatings (FGCs) have a material composition continuously varying through the thickness but uniform in the surface parallel to the coated substrate. When used as a thermal barrier on a metallic substrate, the coating composition varies from an almost pure metal near the substrate to a pure ceramic adjacent to the outer surface exposed to a hot environment. Challenging issues in producing high quality FGCs in the presence of external disturbances with an atmospheric plasma spray process (APSP) include controlling the mean temperature, the mean axial velocity, and the positions of the constituent material particles when they arrive at the substrate to be coated. The unavoidable disturbances include fluctuations in the arc voltage and clogging of the powder in the delivery system. For a two-constituent coating, this work proposes using three modified robust model reference adaptive controllers based on the σ-modified laws and low frequency learning. One controller adjusts the current and flow rates of argon and hydrogen into the torch. The other two controllers adjust the distance of the two powder injector ports from the plasma jet axis and the average injection velocity of each powder. It is shown through numerical experiments that the three controllers implemented in an APSP consistently produce high-quality FGCs.
Interstitial Mycosis Fungoides: An Unusual Mimic of Interstitial Granuloma Annulare Not to Miss
Singh, Neha; Fagan, Kiley K.; Grider, Douglas J. (Hindawi, 2022-09-05)
Interstitial mycosis fungoides is a rare histopathologic variant of mycosis fungoides that may resemble interstitial granuloma annulare, inflammatory morphea, and interstitial granulomatous dermatitis. Reported is a case of a 62-year-old African American female who presented with an asymptomatic, progressive rash of the left underarm and abdomen with histologic features suggestive of granuloma annulare. Biopsies revealed an interstitial pattern of cells in the dermis with prominent small aggregates of atypical lymphocytes, a few atypical lymphocytes in the lower epidermis, and a mild increase in dermal mucin. Immunohistochemistry staining revealed the atypical lymphocytes to be positive for CD3 and CD8 and negative for CD4 and CD7, an aberrant immunoprofile. Mixed in the dermis with the atypical lymphoid cells were a few CD68 positive histiocytes and S100 protein positive dermal dendritic cells. T-cell receptor beta gene rearrangement studies showed nearly the same clonal peaks for TCRB rearrangement in two biopsy specimens from separate sites, all supporting a diagnosis of interstitial mycosis fungoides. The patient is undergoing treatment with full body narrowband UVB (nbUVB) phototherapy with notable improvement in skin discoloration and resolution of several abdominal lesions. A diagnosis of interstitial mycosis fungoides is challenging to make based on clinical features alone and is often clinically misdiagnosed. Awareness of histopathologic features is critical to make an accurate diagnosis and thus patient management.
Prevalence and Associated Risk Factors of African Animal Trypanosomiasis in Cattle in Lambwe, Kenya
Okello, Ivy; Mafie, Eliakunda; Eastwood, Gillian; Nzalawahe, Jahashi; Mboera, Leonard E. G.; Onyoyo, Samuel (Hindawi, 2022-07-14)
Background. African animal trypanosomiasis (AAT) affects livestock productivity in sub-Saharan Africa. This study aimed to determine cattle AAT’s prevalence and associated risk factors in Lambwe Valley, Kenya. Methods. In a cross-sectional survey, livestock owners were recruited from four villages of Lambwe in Homa Bay, Kenya. Blood samples were collected from the jugular veins of cattle, and buffy coat smears were examined under a microscope. Parasites were further detected using polymerase chain reaction (PCR). Using a semistructured questionnaire, livestock owners were interviewed on their knowledge of AAT and control practices. Chi-square and multilevel models were used for the analysis. Results. The overall prevalence was 15.63% (71/454). Trypanosoma vivax 10.31% and T. congolense Savannah 6.01% were the common species and subspecies. A total of 61 livestock keepers were involved in the study. Of these, 91.80% (56/61) knew AAT, and 90.16% (55/61) could describe the symptoms well and knew tsetse fly bite as transmission mode. Self-treatment (54.09%; 33/61) was common, with up to 50.00% of the farmers using drugs frequently. Isometamidium (72.13%; 44/61) and diminazene (54.09%; 33/61) were drugs frequently used. Although 16.39% (10/61) of the farmers claimed to use chemoprophylactic treatment, 6/10 did not use the right drugs. Animals (92.1%; 58/63) with clinical signs had positive infections. Villages closer to the national park recorded a higher prevalence. Infections were higher in cattle owned by those self-treating (27.23%; 58/213), those using drug treatment without vector control (27.62%; 50/181), those using single-drug therapy, and those practicing communal grazing (20.00%; 59/295). Clinical signs strongly associate with positive infections under multilevel modeling. Conclusion. Cattle trypanosomiasis is prevalent in the Lambwe region of Kenya. This is influenced by inappropriate control practices, communal grazing, and the proximity of farms to the national park. In addition, clinical signs of the disease have a strong association with infections.
High-Dose Dexmedetomidine for Severe Hyperactive Delirium Secondary to Intravenous Levetiracetam on Two Separate Occasions in the Same Patient
Ward, Chad; Khalid, Kiran; Rozette, Nicole (Hindawi, 2022-07-02)
We describe the case of a 5-year-old male who developed severe hyperactive delirium with aggressive violent behavior following the administration of IV levetiracetam for the treatment of status epilepticus on two occasions. The child’s symptoms ranged from attacking his parents and the intensive care staff. Risperidone was given without any improvement in symptoms. A high-dose continuous infusion of IV dexmedetomidine was administered, and his violent behavior and delirium significantly improved. The two episodes of hyperactive delirium following IV levetiracetam administration occurred at ages 3 and 5, resulting in extensive work up including laboratory testing and cranial imaging, along with cerebral spinal fluid analysis and were normal. IV dexmedetomidine provided rapid symptom relief to prevent harm for the child, staff, and family on both occasions.
A Case of Childhood Severe Paroxysmal Cold Hemoglobinuria with Acute Renal Failure Successfully Treated with Plasma Exchange and Eculizumab
Pelletier, Jessica; Ward, Chad; Borloz, Matthew; Ickes, Anne; Guelich, Susan; Edwards, Erwood (Hindawi, 2022-04-22)
We describe the case of a 4-year-old female who presented with sepsis and disseminated intravascular coagulation (DIC), developed ongoing intravascular hemolysis with acute renal failure from suspected pigment-induced acute tubular necrosis necessitating continuous renal replacement therapy (CRRT) for five days followed by four episodes of intermittent hemodialysis (iHD), and was subsequently diagnosed with paroxysmal cold hemoglobinuria (PCH). She was successfully treated with plasma exchange and eculizumab, a humanized monoclonal antibody targeting complement protein C5, and demonstrated significant improvement of hemolysis and recovery of renal function.
Prostate-Specific Membrane Antigen as Target for Neuroimaging of Central Nervous System Tumors
Stopa, Brittany M.; Crowley, James; Juhász, Csaba; Rogers, Cara M.; Witcher, Mark R.; Kiser, Jackson W. (Hindawi, 2022-04-15)
Introduction. Positron emission tomography (PET) imaging with prostate-specific membrane antigen- (PSMA-) binding tracers has been found incidentally to demonstrate uptake in CNS tumors. Following the encouraging findings of several such case reports, there is a growing interest in the potential application of PSMA-targeted PET imaging for diagnostics, theranostics, and monitoring of CNS tumors. This is a systematic literature review on PSMA-binding tracers in CNS tumors. Methods. A PubMed search was conducted, including preclinical and clinical reports. One hundred and twelve records were identified, and after screening, 56 were included in the final report. Results. Tissue studies demonstrated PSMA expression in tumor vascular endothelial cells, without expression in normal brain tissue, though the extent and intensity of staining varied by anti-PSMA antibody and methodology. Most included studies reported on gliomas, which showed strong PSMA ligand uptake and more favorable tumor to background ratios than other PET tracers. There are also case reports demonstrating PSMA ligand uptake in prostate cancer brain metastases, nonprostate cancer brain metastases, and meningiomas. We also review the properties of the various PSMA-binding radiotracers available. Therapeutic and theranostic applications of PSMA-binding tracers have been studied, including labeled alpha- and beta-ray emitting isotopes, as well as PSMA targeting in directing MRI-guided focused ultrasound. Conclusions. There is a potential application for PSMA-targeted PET in neuro-oncology as a combination of diagnostic and therapeutic use, as a theranostic modality for managing CNS tumors. Further research is needed regarding the mechanism(s) of PSMA expression in CNS tumors and its differential performance by tumor type.
Initial Presentation of OCD and Psychosis in an Adolescent during the COVID-19 Pandemic
Nazeer, Sahana; Reddy, Abhishek (Hindawi, 2022-04-15)
The COVID-19 pandemic is unparalleled in recent history when accounting for the true disease burden and dramatic impact on physical and mental health. Due to its infectious pathology, COVID-19 presents with a variety of symptoms including neuropsychiatric complications. Moreover, factors such as quarantine, social isolation, and fear of illness have negatively impacted the health of non-COVID-19 patients. There has been significant literature reporting new-onset psychiatric illness in all global populations including those without history of psychiatric illness. This report discusses an adolescent male without prior psychiatric history presenting with new onset symptoms of obsessive-compulsive disorder and psychosis in the context of COVID-19. There are considerable reports describing new-onset obsessive-compulsive disorder, albeit conflicting in terms of prevalence and exacerbations in the setting of COVID-19 in both adult and adolescent populations but limited reports of new-onset psychosis in those same populations and setting.
A Direct Ghost Fluid Method for Modeling Explosive Gas and Water Flows
Si, Nan; Park, Jinwon; Brown, Alan J. (Hindawi, 2022-04-16)
This work presents a Direct Ghost Fluid Method (DGFM) as part of a two-fluid numerical framework suitable to model explosive gas and water flows resulting from underwater explosion (UNDEX). Due to the presence of explosive gas and water with shock waves in the modeling domain, classic Eulerian methods with inherent diffusion may not be effective. Numerical diffusion occurs due to nonphysical diffused density at material interfaces, which creates spurious pressure oscillations and significantly degrades the quality of the numerical results. To eliminate or minimize numerical diffusion, sharp interface methods having no mixed elements may be used in multifluid flow computations. The Direct Ghost Fluid Method (DGFM) described in this paper uses direct extrapolation of density (vice pressure) and tangential velocity from real to ghost fluid. The spurious pressure oscillations near the material interface are therefore minimized. One-, two-, and three-dimensional computational fluid dynamics (CFD) solvers that have DGFM as an essential part in their framework to model UNDEX interface conditions are developed, explored, and applied to the simulation of a series of benchmark problems. Excellent agreement is obtained among the simulations, the analytical solutions, and the experiments.
A Positive Answer on Nirenberg’s Problem on Expansive Mappings in Hilbert Spaces
Asfaw, Teffera M. (Hindawi, 2022-03-17)
Nirenberg proposed a problem as to whether or not a continuous and expansive operator T : X⟶X (where X is a Hilbert space) is surjective if R(T)∘ ≠∅. I shall give a positive answer for the problem provided that R(T)∘ is unbounded. For contents related to this paper, the reader is referred to the remarks and the study of Asfaw (2021). The present paper gives a complete answer for the problem that has been open for about 47 years.
Dynamics of Thermoacoustic Oscillations in Swirl Stabilized Combustor without and with Porous Inert Media
Dowd, Cody; Meadows, Joseph (Hindawi, 2022-02-21)
Lean premixed (LPM) combustion processes are of increased interest to the gas turbine industry due to their reduction in harmful emissions. These processes are susceptible to thermoacoustic instabilities, which are produced when energy added by an in-phase relationship between unsteady heat release and acoustic pressure is greater than energy dissipated by loss mechanisms. To better study these instabilities, quantitative experimental resolution of heat release is necessary, but it presents a significant challenge. Most combustion systems are partially premixed and therefore will have spatially varying equivalence ratios, resulting in spatially variant heat release rates. For laminar premixed flames, optical diagnostics, such as OH chemiluminescence, are proportionally related to heat release. This is not true for turbulent and partially premixed flames, which are common in commercial combustors. Turbulent eddies effect the strain on flame sheets which alter light emission, such that there is no longer a proportional relationship. In this study, phased, averaged, and spatially varying heat release measurements are performed during a self-excited thermoacoustic instability without and with porous inert media (PIM). Previous studies have shown that PIM can passively mitigate thermoacoustic instabilities, and to the best of the authors’ knowledge, this is the first-time that heat release rates have been quantified for investigating the mechanisms responsible for mitigating instabilities using PIM. Heat release is determined from high-speed PIV and Abel inverted chemiluminescence emission. OH chemiluminescence is used with a correction factor, computed from a chemical kinetics solver, to calculate heat release. The results and discussion show that along with significant acoustic damping, PIM eliminates the direct path in which heat release regions can be influenced by incoming perturbations, through disruption of the higher energy containing flow structures and improved mixing.
An Alarming Mimicry of Intra-Abdominal Infections: Acute Appendiceal Diverticulitis
Kim, Youseung; Kesar, Varun; Grider, Douglas J.; Chitnavis, Maithili V. (Hindawi, 2021-11-12)
A 65-year-old woman presented with three days of colicky abdominal pain. Abdominal imaging illustrated small bowel enteritis, ascites in both paracolic gutters, and incidental hepatic steatosis. Although ascites fluid demonstrated high neutrophil count consistent with peritonitis and the patient received adequate antibiotics, she clinically deteriorated. Subsequent exploratory laparotomy revealed necrotic appendix and multiple intra-abdominal abscesses. Histopathology showed acute suppurative appendicitis with multiple other intact small diverticula, indicating likely perforation of inflamed appendiceal diverticula with subsequent abscess formation and abdominal peritonitis. This case highlights the importance of ascites fluid analysis and continued clinical correlation, especially in cases of rare entities with atypical presentations.
Modeling of Tunnel Concrete Lining under Fire and Explosion Damage
Yang, Zhaopeng; Wang, Linbing; Gao, Zhifei (Hindawi, 2021-11-13)
This paper presents studies that focus on fire and explosion-induced damage of tunnel structures by employing the Discrete Element Method (DEM). By assuming a two-dimensional aggregate distribution and reconstructing the digital representation of the experimental concrete blocks, a numerical model of the tunnel lining concrete was established in the PFC2D program. The temperature distribution and the shock wave pressure at the surface of the tunnel lining were obtained by using Fluent and LS-Dyna separately; the final damage simulation of concrete section under different conditions was carried out in PFC2D. The results showed that PFC2D cooperatively provided more accurate and effective modeling and visualization of impact damage of concrete blocks. The visualizations of damage indicated the degree of damage more clearly and more intuitively. These findings also provide a potential method for further study of the damage assessment for entire tunnel lining structures.

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