Air staging application effects on overall steam boiler operation

This paper presents the results of calculation system of main processes in power steam boiler, before and after application of air staging. Modified air injection scheme was implemented during 2015 on the power steam boiler within unit 1 of TPP Kostolac B. Measurements performed on site showed that applied reconstruction led to a permanent loss of the steam boiler power. This study was performed in order to define the cause of such an occurrence and to consider the possibility for regaining the designed steam parameters along with keeping NOx concentration in prescribed limits. This paper discusses the influence of repositioning the air injection location on processes within the furnace. Furthermore, the influence of the redistribution of injected air-flow along the furnace height on important boiler operation parameters has been analyzed. Analysis showed that, with appropriate dosing of air along the height of the existing furnace, it is possible to achieve the optimum of the boiler's operation parameters. Results of research showed that air staging throughout the furnace height in best test case additionally reduces NO concentration (195-225 mg/Nm(3)) and increases the power of x considered boiler (828.8-751.1 MW) with an insignificant decrease of the boiler's efficiency (86.27-86.77%). Furthermore, the designed temperatures of superheated (540-498 degrees C) and reheated (540-518 degrees C) steam have been reached again, whereby the safety of the boiler's operation has been significantly increased. Results of this study improve the present explanation of the processes occurred in the furnace with applied primary measures. They also give directions on defining the most influential parameters on considered processes with the final purpose to increase the efficiency and availability of the entire plant

Air staging application effects on overall steam boiler operation

This paper presents the results of calculation system of main processes in power steam boiler, before and after application of air staging. Modified air injection scheme was implemented during 2015 on the power steam boiler within unit 1 of TPP Kostolac B. Measurements performed on site showed that applied reconstruction led to a permanent loss of the steam boiler power. This study was performed in order to define the cause of such an occurrence and to consider the possibility for regaining the designed steam parameters along with keeping NOx concentration in prescribed limits. This paper discusses the influence of repositioning the air injection location on processes within the furnace. Furthermore, the influence of the redistribution of injected air-flow along the furnace height on important boiler operation parameters has been analyzed. Analysis showed that, with appropriate dosing of air along the height of the existing furnace, it is possible to achieve the optimum of the boiler's operation parameters. Results of research showed that air staging throughout the furnace height in best test case additionally reduces NO concentration (195-225 mg/Nm(3)) and increases the power of x considered boiler (828.8-751.1 MW) with an insignificant decrease of the boiler's efficiency (86.27-86.77%). Furthermore, the designed temperatures of superheated (540-498 degrees C) and reheated (540-518 degrees C) steam have been reached again, whereby the safety of the boiler's operation has been significantly increased. Results of this study improve the present explanation of the processes occurred in the furnace with applied primary measures. They also give directions on defining the most influential parameters on considered processes with the final purpose to increase the efficiency and availability of the entire plant

Atypical pyoderma gangrenosum in a patient with osteomyelofibrosis

Background. Atypical forms of pyoderma gangrenosum generally appear on the upper extremities; most frequently they are associated with myeloproliferative disorders, including osteomyelofibrosis. A response to systemic steroids is more pronounced than in classical form. Sometimes it may be the first sign of an underlying malignancy. Case report. We reported a patient with atypical pyoderma gangrenosum developed during the course of a myeloid malignancy - osteomyelofibrosis. The lesions occurred after a minor trauma. Painful blistering plaques, with an elevated, bluish-gray border were located on the dorsal aspect of hands. No skin malignancy was found. The lesions resolved rapidly to systemic steroids. Conclusion. Considering the unusual clinical presentation which makes the diagnosis difficult, as well as the fact that atypical forms of pyoderma gangrenosum can be the first sign of malignancies, especially myeloproliferative ones, recognizing this entity enables timely guiding future investigations toward their prompt detection

Knowledge and attitudes of high school students about sexually transmitted diseases

Introduction: Sexually transmitted infections represent a public health problem of great importance in most parts of the world. Research goal: The primary aim is determine the sexual activity, attitudes and knowledge of high school students about sexually transmitted diseases. Method: The research conducted is the type of study section. In December, 113 students from first to fourth grade from High School Center Foca were surveyed. In the study used an anonymous questionnaire character. The questionnaire in this research was anonymous. Results: 35.4% of respondents were sexually active. The young men were sexually much more active than girls (χ2 = 30,447; p = 0.001). Most sexually active students said that they had their first sexual intercourse at age 15 (50%%). The boys and girls have diametrically opposed attitudes regarding age in which they find it is the optimal time for their sexual activities (χ2 = 20,252; p = 0.001). Students of the third and fourth grade have a much higher level of knowledge compared to the students of the first and second grade (χ2 = 31,791; p = 0.001). Most students would continue to associate with a person even if that person has one of the sexually transmitted diseases (64.6%). Conclusion: The results of this study show that sexual activity of adolescents surveyed is not a mass phenomenon, but that knowledge of students of first and second grades was insufficient, and that there is a need for education of this target group, considering the importance of preserving reproductive health of adolescents, who are the future of preserving population

Burnout in nurses

Introduction: Burnout syndrome is the answer to chronic, emotional and interpersonal stressors who are related to the workplace. It is characterized by mental or emotional exhaustion, a feeling of fatigue and depression with a more emphasis on psychological than physical symptoms. The aim of this study was to determine the prevalence of burnout syndrome among nurses at the JZU General Hospital Nišić and JZU Health Center Nikšić. Material and methods: The research is designed to the type of section study. The study included 100 nurses at the General Hospital Nikšić and the Health Center Nikšić, different of sex, age, level of education and years of work. The data was collected by the Maslach Burnout Inventory (BMI), consisting of 22 questions posed as a series of claims that are evaluated, using the Likert scale (0-6). Results: Of the total number of respondnents in 36%, there is a burnout syndrome measured by the total MBI score, compared to 64% of subjects with no burnout syndrome. With the help of MBI scale it was found that 8% of respondents have a high level of emotional exhaustion, 38% have a middle level, and the remaining 53% of nurses and technicians have a low level. Conclusion: Based of the results of this research, we can conclude that sex and age of nurses / technicians do not affect the occurrence of a professional burnout syndrome. The nurses / technicians working in primary health care in a significantly lower percentage have a mean level of depersonalization. Also, nurses / technicians with longer length of service show a low level of personal success (achievements)

Comparison of radiative heat transfer models used in numerical simulations of boiler furnaces

Toplotno zračenje je dominantni mod prostiranja toplote sa vrućih produkata sagorevanja ka zidovima ložišta. Tačnost računanja flukseva zračenja je od suštinskog značaja za tačnost numeričkih simulacija, kojima se mogu predvideti performanse celokupnog procesa. Do sada je razvijeno nekoliko modela razmene toplote zračenjem, koji se mogu svrstati u fluksne, zonalne i hibridne modele. Reprezentativni modeli zračenja svake grupe opisani su u radu. Poređenje modela predstavljeno je za laboratorijsko ložište, za koje su prethodno određene tačne vrednosti neto razmenjenih energija zapreminskih zona i neto razmenjenih flukseva površinskih zona. Poređenje pokazuje da su zonalni modeli tačniji od fluksnih modela, čime se preporučuje njihova primena za numeričke simulacije ložišta za sagorevanje fosilnih goriva.Thermal radiation is dominant mode of heat transfer from hot combustion products to the furnace walls. Accuracy of calculation of the heat exchanged by thermal radiation is essential for the accuracy of numerical simulation, by which performances of the whole process can be predicted. So far, several models of radiative heat exchange have been developed, which can be grouped into flux, zonal, and hybrid models. Representative models of each group have been described. Comparison of the models have been performed for the laboratory furnace, for which the exact values of radiative source term and net exchanged heat of furnace walls have been previously determined. Comparison shows that zonal models are more accurate than flux models and suggests their application for the numerical simulation of furnace for fossil fuel combustion

Numerical determination of the pulverized coal flame radiative properties

Ispitan je uticaj broja čestica letećeg pepela koje nastaju fragmentacijom jedne čestice koksnog ostatka na radijaciona svojstva disperzne faze plamena ugljenog praha, kao i da li se primenom tako dobijenih radijacionih svojstava disperzne faze može dobiti slaganje rezultata numeričkih istraživanja sa rezultatima merenja. Za uslove sagorevanja unutar ložišta bloka A2 TENT snage 210 MNJ, koncentracija čestica letećeg pepela i funkcija raspodele su određeni pod pretpostavkom da jedna čestica koksnog ostatka formira od jedne do pet čestica letećeg pepela. Radijaciona svojstva oblaka čestica letećeg pepela izračunata su metodom nepravilne difrakcije. Rezultati pokazuju da sa porastom broja čestica letećeg pepela koje nastaju od jedne čestice koksnog ostatka rastu vrednosti koeficijenata apsorpcije i rasipanja zračenja, ali opada njihov odnos. Vrednosti radijacionih svojstava upotrebljene su u diferencijalnom matematičkom modelu procesa unutar izabranog ložišta. Koeficijent apsorpcije gasne faze određen je modelom jednog sivog gasa i u svim ispitivanim slučajevima bio je konstantan. Istraživanje je pokazalo da porast koeficijenta apsorpcije disperzne faze dovodi do porasta temperature gasne faze i flukseva upadnog zračenja, kao i da se slaganje sa rezultatima merenja postiže za sve izračunate vrednosti radijacionih svojstava disperzne faze.Influence of the number of particles that are formed by fragmentation of one char particle on radiative properties of the dispersed phase of the pulverized coal flame, as well as on the results of numerical investigation of the process have been investigated. For the combustion conditions inside the furnace of A2 TENT 210 MW thermal unit, concentration of the flyash particles and particle size distribution parameters have been determined under assumption that one char particle forms from one to five flyash particles. Radiative properties of the cloud of flyash particles have been determined using anomalous diffraction method. Results show that increase of the number of flyash particles leads to the increase of the absorption and scattering coefficients. The differential mathematical model has been formed, for the process inside the chosen furnace. The absorption coefficient of the gas phase has been obtained by application of the simple gray gas model, and its value has been kept constant in all examined cases. Results show that increase of the dispersed phase absorption Coefficient leads to the increase of the gas-phase temperature and incident radiative fluxes. Agreement with the results of measurement has been achieved for all values of the dispersed phase radiative properties

Applicability and prognostic significance of geriatric assessment

Aging implies a process during which changes occur in the function of all organic systems in the human body. For a detailed assessment of the health status of an elderly person, a comprehensive geriatric assessment (CGA) is recommended. CGA is defined as a multidisciplinary diagnostic and therapeutic approach that enables the identification of medical, psychosocial and functional limitations of an elderly person, all with the aim of developing a coordinated plan to improve the health of the elderly person. The aim of this review was to point out the significance, comprehensiveness, applicability and prognostic significance of geriatric assessment based on data from recent literature and by searching available electronic databases. Studies were collected from the electronic databases MEDLINE (via Ovid), Pubmed, COBSON database and Google Scholar database, as well as by manual search of relevant studies cited in the references of key articles. The search for papers as a whole is limited to the English language. All studies that used a comprehensive geriatric assessment in their methodology, in elderly people over 65 years of age, were included. CGA is very important for the elderly, for their families, health systems of countries, health professionals as well as the social community. Interventions resulting from a CGA are one way to improve the performance of activities of daily living in elderly patients. CGA has numerous advantages in practice, it is comprehensive, applicable, economically relatively acceptable and as such can be routinely implemented at different levels of health care. CGA has a high prognostic significance for the early detection of multimodal problems in the geriatric population

Numerical optimisation of processes in the furnace considering NOx emission and efficiency of utility boiler

Razvijen je matematički model, namenjen za predviđanje procesa u energetskim parnim kotlovima TE Kostolac B tangencijalno loženim sprašenim lignitom. Model je primenjen za numeričku analizu rada kotla radi smanjenja emisije NOx, uz istovremeno održavanje visokog stepena korisnosti kotla. Kompleksni dvofazni tok gas-čestice modeliran je Ojler-Lagranževim pristupom. Povezivanje faza je ostvareno kuplovanjem pomoću PSI-Cell koncepta. Radi ostvarivanja željenih analiza, ugrađen je pod-model formiranja/destrukcije NO, unutar složenog koda za sagorevanje, koji se koristi za predviđanje emisije na izlazu iz ložišta. Modelirani su termički i gorivi NO, kao najuticajniji oksidi azota pri sagorevanju ugljenog praha. Proračunski program je razvijen radi lakše upotrebe od strane inženjerskog osoblja prilikom analiza procesa u kotlovskim postrojenjima. Numeričke simulacije su izvršene za različite radne uslove kotla, prilikom loženja lignitom sa kopa Drmno. Suprotstavljeni zahtevi a smanjenjem emisije i efikasnim sagorevanjem, sa osvrtom na bezbedan rad pregrejača pare često zahtevaju rad kotla u uskim granicama radnih parametara, koji su utvrđeni pomoću termičkog proračuna kotla.Mathematical model, aimed for prediction of processes in TE Kostolac B power plant utility boiler furnace tangentially fired by pulverized lignite, was developed in-house. The model was applied in numerical analysis of boiler operation, in order to reduce NOx emission by combustion modifications in the furnace, while maintaining high efficiency of the boiler unit. Complex two-phase gas-particle flow was modelled using Euler-Lagrange approach. Coupling between phases was done by using PSI-Cell concept. In order to perform necessary analysis, NO formation/destruction sub-model was implemented, within comprehensive combustion code, used to predict emission from the furnace. Thermal and fuel NO were modelled, as the most influential nitrogen oxides during pulverized coal combustion process. The computational code was developed to be easily used by engineering staff dealing with the process analysis in boiler units. Numerical simulations were performed for the boiler fired by the lignite Drmno, under different operating conditions. Contradictory requirements with respect to emission reduction and efficient combustion with safe operation of super-heaters often require boiler to operate within narrow limits of operation parameters, which is determined by means of the boiler thermal calculation

Treatment of surgical wounds on the uterus after laparoscopic myomectomy

Introduction. The advantages of laparoscopic removal of a myoma over classical surgical technique are shorter hospital stay, rapid recovery and less pain after surgery, as well as a lower frequency of ileus and thromboembolic complications. The surgical technique of laparoscopic removal of myoma involves four basic stages: incision on the wall of the uterus, separation of the myoma from the healthy uterine tissue, to stop bleeding and removal of the myoma from the abdomen. Apart from these four basic stages, it is also necessary to establish a new integrity of the uterine wall, especially in women planning pregnancy. Objective. The aim of the paper is to present the procedures used in the treatment of uterine wall defect during the laparoscopic removal of the myoma. Methods. We analyzed 96 patients who were indicated for laparoscopic myomectomy. All patients were divided into four groups according to the type of the technique of haemostasis and treatment of the defect on the uterine wall: electrocoagulation, electrocoagulation with application of argon plasma, a single suture and extended suture. Results. In order to stop bleeding, we most often used electrocoagulation by monopolar electricity, i.e. in 39.6% of the patients. To stop bleeding and treat the defect of the uterine wall, we used a single suture in 21.9% and in 11.4% patients we used the extended suture. The manner of uterine wall treatment did not have a statistically significant influence on the results of haematological parameters (p>0.05), consumption of carbon dioxide (p>0.05) and the duration of surgical procedure (p>0.05). The increased use of antibiotics (p<0.05) in the group of patients in whom we treated the defect by sutures on the uterus, the length of postsurgical hospitalization and absence from work (p<0.01) was statistically significant. Conclusion. To achieve a better reconstruction of the uterus, it is recommended to use sutures with laparoscopic removal of myoma