Identification of Rub and Unbalance in a 320MW Turbogenerators

The paper presents two experiences of application of a model based fault identification method on real machines. The first case presented is an unbalance identification on a 320MW turbogenerator unit operating in a fossil power plant. In the second case, concerning a machine of the same size but of a different manufacturer, the LP turbine was affected by a rub in the sealings. This time, the fault is modeled by local bows. The identification of the faults is performed by means of a model based identification technique in frequency domain, suitably modified in order to take into account simultaneous faults. The theoretical background of the applied method is briefly illustrated and some considerations are presented also about the best choice of the rotating speed set of the run-down transient to be used for an effective identification and about the appropriate weighting of vibration measurements at the machine bearings

Use of Modal Representation for the Supporting Structure in Model Based Fault Identification of Large Rotating Machinery: Part 2: Application to a Real Machine

Model-based techniques are often employed in diagnostics of rotating machines to locate and to evaluate the severity of a malfunction. The use of a reliable model can increase the accuracy of identification. Rigid supports or lumped mass pedestals are not always enough to account for foundation dynamics; a modal representation of the supports can improve the identification results. The method, discussed in the first part, is here validated using experimental data of a 320 MW steam turbogenerator. To the authors’ knowledge, this is the first case of fault identification on real data from a large machine, where the supporting structure is accounted for by means of a modal model

Use of Modal Representation for the Supporting Structure in Model Based Fault Identification of Large Rotating Machinery: Part 1 – Theoretical Remarks

Fault identification by means of model-based techniques, both in frequency and time domain, is often employed in diagnostics of rotating machines, when the main task is to locate and to evaluate the severity of the malfunction. The model of the fully assembled machine is composed by the submodels of the rotor, of the bearings and of the foundation, while the effect of the faults is modelled by means of equivalent force systems. Some identification techniques, such as the least squares identification in frequency domain, proposed by the authors, have proven to be quite robust even if the submodels are not fine-tuned. Anyhow, the use of a reliable model can increase the accuracy of the identification. Normally a supporting structure is represented by means of rigid foundation or by pedestals, i.e. 2 d.o.f. mass–spring–damper systems, but these kind of models are often not able to reproduce correctly the influence of the dynamical behaviour of the supporting structure on the shaft, especially in large machines where coupled modes are present. Therefore, peculiar aspect of this paper is the use of a modal foundation to model the supporting structure of the machine and the method is discussed in detail in this first part. The modal representation of the foundation is then introduced in the least squares identification technique in frequency domain

Antivirals in medical biodefense

The viruses historically implicated or currently considered as candidates for misuse in bioterrorist events are poxviruses, filoviruses, bunyaviruses, orthomyxoviruses, paramyxoviruses and a number of arboviruses causing encephalitis, including alpha- and flaviviruses. All these viruses are of concern for public health services when they occur in natural outbreaks or emerge in unvaccinated populations. Recent events and intelligence reports point to a growing risk of dangerous biological agents being used for nefarious purposes. Public health responses effective in natural outbreaks of infectious disease may not be sufficient to deal with the severe consequences of a deliberate release of such agents. One important aspect of countermeasures against viral biothreat agents are the antiviral treatment options available for use in post-exposure prophylaxis. These issues were adressed by the organizers of the 16th Medical Biodefense Conference, held in Munich in 2018, in a special session on the development of drugs to treat infections with viruses currently perceived as a threat to societies or associated with a potential for misuse as biothreat agents. This review will outline the state-of-the-art methods in antivirals research discussed and provide an overview of antiviral compounds in the pipeline that are already approved for use or still under development

Lactobacillus johnsonii LJO02 (DSM 33828) Cell-Free Supernatant and Vitamin D Improve Wound Healing and Reduce Interleukin-6 Production in Staphylococcus aureus-Infected Human Keratinocytes

Methicillin-resistant biofilm-forming Staphylococcus spp. are found in about 25% of the overall cases of chronic wounds, which can undergo malignant degeneration and be associated with skin cancer. Although antimicrobial agents are clinically used to counteract pathogens and promote wound healing, they are increasingly ineffective against multi-drug resistant bacteria. Moreover, they can induce dysbiosis, which favors opportunistic pathogen infections and alters immune responses. Consequently, research on pathogen containment strategies is crucial. We aimed to evaluate the potential beneficial effect of Lactobacillus johnsonii LJO02 cell-free supernatant (CFS) and vitamin D, as single treatments or in combination, on cell viability, wound healing, and the pro-inflammatory interleukin-6 (IL-6) production of a Staphylococcus aureus-infected human immortalized keratinocyte cell line (HaCaT) in vitro model. The analysis showed that LJO02 CFS 20% v/v ratio and 100 nM vitamin D promoted infected cell viability and wound healing and significantly reduced IL-6 production. However, their effect was not synergic, since no significant difference between the single and combined treatments was observed. LJO02 CFS topic application and vitamin D supplementation could provide a valuable strategy for attenuating S. aureus-induced pathogenesis, promoting wound healing and opening new therapeutic strategies supporting the conventional approaches

Human respiratory syncytial virus in children hospitalized for acute lower respiratory infection

OBJETIVO: Avaliar a prevalência e a sazonalidade do vírus respiratório sincicial humano (VRSH) em crianças de 0 a 6 anos hospitalizadas por infecção aguda das vias aéreas inferiores (IVAI) em São José do Rio Preto (SP) e a associação entre faixa etária, diagnóstico e VRSH. MÉTODOS: Entre maio de 2004 e setembro de 2005, foram estudados 290 episódios consecutivos de IVAI adquiridos na comunidade em crianças de 0 a 6 anos internadas no Hospital de Base de São José do Rio Preto. Para identificação do VRSH, foram coletadas amostras de secreção de nasofaringe e realizou-se análise molecular por meio da técnica de RT-PCR. RESULTADOS: A prevalência de VRSH foi de 29,3% nos episódios de IVAI hospitalizados. A IVAI foi frequente em lactentes (mediana de idade = 13,5 meses). O VRSH foi mais frequente nos casos de bronquiolite (64%) e no primeiro ano de vida (35%). Os episódios de infecção por VRSH ocorreram entre o outono e a primavera, com frequência maior em 2004 do que em 2005. Os critérios clínicos e radiológicos não foram suficientes para o diagnóstico de infecção pelo VRSH. Em 78,8% dos episódios de VRSH, houve tratamento com antibiótico. CONCLUSÕES: A prevalência do VRSH em crianças de 0 a 6 anos hospitalizadas por IVAI foi elevada, com predomínio nas mais jovens ou com bronquiolite. A circulação do vírus variou nos dois anos estudados. Os resultados sugerem necessidade de diagnóstico laboratorial do VRSR na prática clínica.OBJECTIVE: To evaluate the prevalence and seasonality of human respiratory syncytial virus (HRSV) in children aged 0 to 6 years, hospitalized with acute lower respiratory infection (ALRI) in São José do Rio Preto, SP, Brazil, and the association between age, diagnosis, and HRSV. METHODS: Between May 2004 and September 2005, we studied 290 consecutive episodes of community-acquired ALRI in children aged 0 to 6 years admitted to the Hospital de Base of São José do Rio Preto. In order to detect HRSV, nasopharyngeal secretion samples were collected and RT-PCR molecular analysis was performed. RESULTS: The HRSV prevalence was 29.3% for the cases of hospitalized patients with ALRI. ALRI was common in infants (median age = 13.5 months). HRSV was more frequent in cases of bronchiolitis (64%) and during the first year of life (35%). Episodes of HRSV infection occurred between fall and spring, showing higher frequency in 2004 than in 2005. Clinical and radiological criteria were not sufficient to establish the diagnosis of infection with HRSV. Antibiotic therapy was used in 78.8% of episodes of HRSV. CONCLUSIONS: There was a high prevalence of HRSV in children aged 0 to 6 years who were hospitalized for ALRI, predominantly in younger patients or those with bronchiolitis. The circulation of the virus varied in the two years studied. Our results suggest the need for laboratory diagnosis of HRSV in the clinical practice