This paper describes the physical, chemical and mineral properties of ash and slag, which were taken from thermal power plants Nikola Tesla A, Nikola Tesla B, Kostolac A and Kostolac B. The knowledge ...of the mineralogical material composition is important because the type of minerals directly determines the properties of the fly ash and slag and their possible application. Laboratory tests showed that ash and slag samples consist of the following minerals: amorphous materials, quartz, feldspar, mullite, melilite, cristobalite, haematite and calcite. The fly ash and slag chemical properties are the most important indicators in the evaluation of their suitability as a building material. The ash and slag chemical composition is composed of the following chemical components: SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, S, Na2O and K2O. Results of laboratory tests show that fly ash and slag have variable chemical, mineralogical and physical properties that are dependent on the natural composition, quality of coal from basin, the manner of combustion and place of ash deposition.
An experimental research of physicomechanical properties of fly ash and ash stabilized with lime and cement, as used in road construction, is presented in the paper. The binder was added in the ...proportion of 2, 4 and 6 % of the total quantity of fly ash. The testing revealed that ash samples with and without binder can be used for improvement of foundation soil and for construction of embankments and subgrade layers, but are not recommended for construction of subbase and base courses. The research is based on the use of fly ash for road construction, i.e. as a substitute for natural materials in construction industry, as this use would save natural resources whose reserves are limited.
This paper describes the physical, chemical and mineral properties of ash and slag, which were taken from thermal power plants Nikola Tesla A, Nikola Tesla B, Kostolac A and Kostolac B. The knowledge ...of the mineralogical material composition is important because the type of minerals directly determines the properties of the fly ash and slag and their possible application. Laboratory tests showed that ash and slag samples consist of the following minerals: amorphous materials, quartz, feldspar, mullite, melilite, cristobalite, haematite and calcite. The fly ash and slag chemical properties are the most important indicators in the evaluation of their suitability as a building material. The ash and slag chemical composition is composed of the following chemical components: SiO^sub 2^, Al^sub 2^O^sub 3^, Fe^sub 2^O^sub 3^, CaO, MgO, SO^sub 3^, S, Na^sub 2^O and K^sub 2^O. Results of laboratory tests show that fly ash and slag have variable chemical, mineralogical and physical properties that are dependent on the natural composition, quality of coal from basin, the manner of combustion and place of ash deposition.
Fly ash is one of the most common waste materials created by burning of coal. It is composed of smaller particles, consisting mainly of aluminosilicate-glass, mullite and quartz, which are collected ...by electrostatic separators (filter) of gaseous products arising from the combustion of coal. This paper presents the pozzolanic properties, mechanical properties, chemical and mineral composition of fly ash obtained in the combustion process in a power plant Nikola Tesla A (PPNT A) with the addition of a binder hydrated lime and cement. The aim of research is to test the possibility of using the fly ash from PPNT A for making elements of road structures (top and bottom layers of the road). Fly ash can be used to create elements for road structures, but it must be taken into account that the embedding is done in segments, isolated from the influence of surface water and groundwater.
U radu je prikazano eksperimentalno istraživanje fizikalno-mehaničkih svojstava letećeg pepela i stabiliziranog pepela s dodatkom vapna i cementa primjenjivog za gradnju cesta. Vezivo je dodavano sa ...2, 4 i 6 % u odnosu na ukupnu količinu letećeg pepela. Nakon izvršenih ispitivanja uočljivo je da uzorci pepela bez dodataka i s dodatkom veziva mogu koristiti za izradu temeljnog tla, nasipa i posteljice, dok za izradu nosivih slojeva nisu preporučljivi. Istraživanje se temelji na korištenju letećeg pepela za izgradnju cesta, odnosno kao zamjena prirodnim materijalima u građevinarstvu, pri čemu se štede prirodni resursi čije su rezerve ograničene.
Elektrofilterski pepeo (leteći pepeo) je jedan od najzastupljenijih otpadnih materijala nastao sagorijevanjem uglja. Čine ga sitnije čestice, sastoji se uglavnom od amorfno-staklastog materijala, ...mulita i kvarca, koji se sakuplja elektrostatičkim separatorima (filterima) iz plinovitih produkata nastalih uslijed sagorijevanja uglja. U radu su prikazana pucolanska svojstva, mehanička svojstva, kemijski i mineralni sastav i svojstva elektrofilterskog pepela dobivenog u procesu sagorijevanja u termoelektrani Nikola Tesla A (TENT A) s dodatkom veziva hidratiziranog vapna i cementa. Cilj istraživanja je mogućnost uporabe elektrofilterskog pepela za izradu elemenata cestovnih konstrukcija (gornji i donji stroj puta). Elektrofilterski pepeo se može primjenjivati za izradu elemenata cestovne konstrukcije, ali treba voditi računa da se ugrađivanje odvija u segmentima, izoliranim od utjecaja površinskih i podzemnih voda.
Introduction. Metastatic head and neck carcinoma (HNC) from an unknown primary tumor is defined as a metastatic disease in the neck?s lymph nodes without evidence of a primary tumor after appropriate ...investigation. Multiple national guidelines recommend taking essential steps in diagnostic protocols which involve a detailed clinical exam with radiological imaging, fine-needle aspiration (FNA) biopsy of the cervical tumor, esophagogastroduodenoscopy (EGD) with palatine and lingual tonsillectomy, immunohistochemical staining, and human papillomavirus (HPV) detection. Treatment of HNCs of unknown primary origin involves surgery (neck dissection) with radiotherapy (RT), while some authors recommend chemo-radiotherapy in cases of advanced regional disease. Case report. A 44-year-old male was referred to the tertiary medical center because of a large ulcero-infiltrative cervical mass on the right side. Examination of the head and neck and flexible nasopharyngolaryngeal endoscopy was conducted, followed by computed tomography (CT) of the head, neck, and thorax with intravenous contrast. The primary localization of the tumor was not confirmed by these diagnostic methods. An open biopsy of the neck mass established a histopathology diagnosis of metastatic squamous cell carcinoma (SCC). Results of EGD with biopsies and bilateral tonsillectomy were negative for malignancy. Treatment included extended radical neck dissection with reconstruction and postoperative ipsilateral RT. The patient presented with an extensive pharyngolaryngeal tumor five years after the first surgery. Biopsy with histopathology examination confirmed the diagnosis of SCC. Conclusion. A structured step-by-step diagnostic approach to identifying the primary site of the metastatic HNC is mandatory. Substantial advances in diagnostics and operative techniques have increased the likelihood of primary tumor identification and detection of the disease's regional and systemic spread. The purpose of adherence to guidelines results in higher overall survival and longer regional disease-free survival in these patients.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
To correlate the recurrence of temporalis fascia graft perforation and retraction in adults and children after tympanoplasty for chronic tubotympanic otitis and deep attic retraction pockets with ...age, pathologic process, mucosal lesions, mucociliary transport time, chronic sinusitis, and lateral attic wall reconstruction.
Retrospective study.
Tertiary referral center.
Two hundred seventy-four adult ears and 41 child ears were operated on for chronic tubotympanic otitis, 50 adult ears were operated on for traumatic tympanic membrane rupture, and 56 adult ears were operated on for attic retraction pockets.
Underlay tympanoplasty with or without mastoidectomy and lateral attic wall reconstruction for attic retraction pockets. Mucociliary transport time was investigated using saccharin testing.
Recurrent perforation, recurrent attic retraction, and temporalis fascia graft retraction were evaluated.
Higher incidences of recurrent perforation were found in adults operated on for tubotympanic otitis vs traumatic tympanic membrane rupture (P = .02) and in children (P = .004), especially those 9 years and younger (P = .02). A risk factor in adults was chronic sinusitis (risk ratio, 35.0; 95% confidence interval, 32.1-38.2; P = .004). Temporalis fascia graft retraction correlated with slower mucociliary transport time in adults (P < .001). A lower incidence of recurrent attic retraction was associated with lateral attic wall reconstruction (P < .001).
Recurrent temporalis fascia graft perforation after tympanoplasty for tubotympanic otitis may be related to age and coexisting chronic sinusitis. Temporalis fascia graft retraction correlates with slower mucociliary transport time in the eustachian tube. Lateral attic wall reconstruction minimizes recurrent attic retraction in adults.