Structure and Corrosion Resistance of Nickel–Molybdenum Alloy Coatings

Electrolytic Ni–Mo alloy coatings were obtained from the galvanic bath, at the temperature of T = 60 C under galvanostatic conditions using a cathodic current density of j = 80 mA cm2. Surface morphology was studied using a scanning electron microscopy. Chemical composition of obtained coatings was determined by the energy dispersive spectroscopy. Structural studies were carried out using an X-ray diffraction method. Electrochemical corrosion resistance tests were carried out in 5% NaCl solution. It was found that X-ray diffraction investigations of all obtained coatings showed the characteristic “halo”, which suggests that the obtained deposits have an amorphous structure. Chemical composition and corrosion resistance of the electrolytic Ni–Mo coatings depend on the concentration of Na2MoO4 2H2O in a galvanic bath. With the increase of the molybdenum content in the alloy coatings, their corrosion resistance increases

Estimating the incidence of acute infectious intestinal disease in the community in the UK:A retrospective telephone survey

Objectives: To estimate the burden of intestinal infectious disease (IID) in the UK and determine whether disease burden estimations using a retrospective study design differ from those using a prospective study design. Design/Setting: A retrospective telephone survey undertaken in each of the four countries comprising the United Kingdom. Participants were randomly asked about illness either in the past 7 or 28 days. Participants: 14,813 individuals for all of whom we had a legible recording of their agreement to participate Outcomes: Self-reported IID, defined as loose stools or clinically significant vomiting lasting less than two weeks, in the absence of a known non-infectious cause. Results: The rate of self-reported IID varied substantially depending on whether asked for illness in the previous 7 or 28 days. After standardising for age and sex, and adjusting for the number of interviews completed each month and the relative size of each UK country, the estimated rate of IID in the 7-day recall group was 1,530 cases per 1,000 person-years (95% CI: 1135 – 2113), while in the 28-day recall group it was 533 cases per 1,000 person-years (95% CI: 377 – 778). There was no significant variation in rates between the four countries. Rates in this study were also higher than in a related prospective study undertaken at the same time. Conclusions: The estimated burden of disease from IID varied dramatically depending on study design. Retrospective studies of IID give higher estimates of disease burden than prospective studies. Of retrospective studies longer recall periods give lower estimated rates than studies with short recall periods. Caution needs to be exercised when comparing studies of self-reported IID as small changes in study design or case definition can markedly affect estimated rates

Healthcare use for acute gastrointestinal illness in two Inuit communities: Rigolet and Iqaluit, Canada

Background. The incidence of self-reported acute gastrointestinal illness (AGI) in Rigolet, Nunatsiavut, and Iqaluit, Nunavut, is higher than reported elsewhere in Canada; as such, understanding AGI-related healthcare use is important for healthcare provision, public health practice and surveillance of AGI. Objectives: This study described symptoms, severity and duration of self-reported AGI in the general population and examined the incidence and factors associated with healthcare utilization for AGI in these 2 Inuit communities. Design: Cross-sectional survey data were analysed using multivariable exact logistic regression to examine factors associated with individuals’ self-reported healthcare and over-the-counter (OTC) medication utilization related to AGI symptoms. Results: In Rigolet, few AGI cases used healthcare services [4.8% (95% CI=1.5-14.4%)]; in Iqaluit, some cases used healthcare services [16.9% (95% CI=11.2-24.7%)]. Missing traditional activities due to AGI (OR=3.8; 95% CI=1.18-12.4) and taking OTC medication for AGI symptoms (OR=3.8; 95% CI=1.2-15.1) were associated with increased odds of using healthcare services in Iqaluit. In both communities, AGI severity and secondary symptoms (extreme tiredness, headache, muscle pains, chills) were significantly associated with increased odds of taking OTC medication. Conclusions: While rates of self-reported AGI were higher in Inuit communities compared to non-Inuit communities in Canada, there were lower rates of AGI-related healthcare use in Inuit communities compared to other regions in Canada. As such, the rates of healthcare use for a given disease can differ between Inuit and non-Inuit communities, and caution should be exercised in making comparisons between Inuit and non-Inuit health outcomes based solely on clinic records and healthcare use

Large and prolonged food-borne multistate hepatitis A outbreak in Europe associated with consumption of frozen berries, 2013 to 2014

In May 2013, Italy declared a national outbreak of hepatitis A, which also affected several foreign tourists who had recently visited the country. Molecular investigations identified some cases as infected with an identical strain of hepatitis A virus subgenotype IA. After additional European Union/European Economic Area (EU/EEA) countries reported locally acquired and travel-related cases associated with the same outbreak, an international outbreak investigation team was convened, a European outbreak case definition was issued and harmonisation of the national epidemiological and microbiological investigations was encouraged. From January 2013 to August 2014, 1,589 hepatitis A cases were reported associated with the multistate outbreak; 1,102 (70%) of the cases were hospitalised for a median time of six days; two related deaths were reported. Epidemiological and microbiological investigations implicated mixed frozen berries as the vehicle of infection of the outbreak. In order to control the spread of the outbreak, suspected or contaminated food batches were recalled, the public was recommended to heat-treat berries, and post-exposure prophylaxis of contacts was performed. The outbreak highlighted how large food-borne hepatitis A outbreaks may affect the increasingly susceptible EU/EEA general population and how, with the growing international food trade, frozen berries are a potential high-risk food

Measuring underreporting and under-ascertainment in infectious disease datasets: a comparison of methods

Gibbons CL, Mangen M-JJ, Plaß D, et al. Measuring underreporting and under-ascertainment in infectious disease datasets: a comparison of methods. BMC Public Health. 2014;14(1): 147.Background: Efficient and reliable surveillance and notification systems are vital for monitoring public health and disease outbreaks. However, most surveillance and notification systems are affected by a degree of underestimation (UE) and therefore uncertainty surrounds the 'true' incidence of disease affecting morbidity and mortality rates. Surveillance systems fail to capture cases at two distinct levels of the surveillance pyramid: from the community since not all cases seek healthcare (under-ascertainment), and at the healthcare-level, representing a failure to adequately report symptomatic cases that have sought medical advice (underreporting). There are several methods to estimate the extent of under-ascertainment and underreporting. Methods: Within the context of the ECDC-funded Burden of Communicable Diseases in Europe (BCoDE)-project, an extensive literature review was conducted to identify studies that estimate ascertainment or reporting rates for salmonellosis and campylobacteriosis in European Union Member States (MS) plus European Free Trade Area (EFTA) countries Iceland, Norway and Switzerland and four other OECD countries (USA, Canada, Australia and Japan). Multiplication factors (MFs), a measure of the magnitude of underestimation, were taken directly from the literature or derived (where the proportion of underestimated, under-ascertained, or underreported cases was known) and compared for the two pathogens. Results: MFs varied between and within diseases and countries, representing a need to carefully select the most appropriate MFs and methods for calculating them. The most appropriate MFs are often disease-,country-, age-, and sex-specific. Conclusions: When routine data are used to make decisions on resource allocation or to estimate epidemiological parameters in populations, it becomes important to understand when, where and to what extent these data represent the true picture of disease, and in some instances (such as priority setting) it is necessary to adjust for underestimation. MFs can be used to adjust notification and surveillance data to provide more realistic estimates of incidence

Possibilities and motives of choosing study after liquidation the Mining and Geology field of study at the Education Center for Engineers in Rybnik

W artykule przedstawiono wyniki badań ankietowych dotyczące motywacji podejmowania decyzji związanej z wyborem kierunku kształcenia w odniesieniu do oczekiwań respondentów o możliwościach późniejszej kariery zawodowej. Badania odniesiono do faktu likwidacji filii Wydziału Górnictwa i Geologii Politechniki Śląskiej, która przez lata funkcjonowała w Rybniku w Centrum Kształcenia Inżynierów. Celem artykułu jest uzyskanie odpowiedzi na pytanie: czy osoby zainteresowane studiowaniem kierunku górnictwa będą skłonne na dojazd kilkudziesięciu kilometrów do Gliwic w celu pobierania nauki. Przeprowadzone badania ankietowe na grupie studentów pozwoliły również uzyskać wiedzę na temat wielkości „siły dążeń” respondentów do realizacji określonego danego celu. Otrzymane wyniki badań mogą mieć zastosowanie praktyczne przy planowaniu ilości studentów chętnych do kształcenia na Wydziale Górnictwa i Geologii Politechniki Śląskiej.The paper presents the results of a survey on the motivation for decision-making related to the choice of the field of study with regard to the respondents' expectations about the opportunities for their prospective professional career. The research referred to the closure of the part of the Faculty of Mining and Geology of the Silesian University of Technology, which was acting for years at the Centre for the Education of Engineers in Rybnik. The paper addresses the question of whether people showing interest in studying mining may be willing to commute a dozen or so kilometers between their residence and Gliwice to receive education. Surveys carried out on a group of students allowed to obtain knowledge about the size of the "aspirations strength" to attaining particular objectives of respondents. Results of the tests may be practically applied by forecasting number of students expected to study at the Faculty of Mining and Geology of the Silesian University of Technology

Applications for hydraulic backfill mixture of sand with energetic slag

Piasek kopany od kilkudziesięciu lat z powodzeniem wykorzystywany jest jako materiał podsadzkowy do wypełniania pustek podziemnych celem ochrony powierzchni przed szkodami górniczymi. Biorąc od uwagę, że eksploatacja z wykorzystaniem podsadzki hydraulicznej jest bardziej czasochłonna i kosztowniejsza w porównaniu do eksploatacji na zawał stropu od wielu lat prowadzone są prace badawcze nad wprowadzeniem do mieszaniny podsadzkowej tańszych materiałów alternatywnych najczęściej pochodzenia odpadowego. W referacie przedstawiono wyniki badań mieszanin piasku podsadzkowego pozyskanego z kopalni „Maczki-Bór” z odpadem energetycznym w postaci żużlu na zgodność z normą PN-G/11010 „Materiały do podsadzki hydraulicznej. wymagania i badania”. W ramach badań wykonano następujące oznaczenia: składu ziarnowego, rozmywalności, składu chemicznego i wymywalności substancji szkodliwych, promieniotwórczości oraz ścioeliwości. Do badań wykorzystano mieszanki piasku z żużlem o udziale masowym żużlu w ilości 0, 5, 10, 15 i 20%. Na podstawie wykonanych badań można stwierdzić, że badane materiały w postaci piasku kopanego jak i żużel energetyczny oraz ich mieszaniny spełniają wymagania normowe i mogą mieć zastosowanie do podsadzki hydraulicznej. Zastosowanie żużlu energetycznego jako składnika podsadzki posiada również aspekt ekologiczny, wpływając korzystnie na ochronę środowiska poprzez ograniczenie jego skladowania.For decades, sand has successfully been used as a material for filling underground cavities to protect the surface terrain against mining damage. Hydraulic backfill operations are more time-consuming and expensive than the caving operation, thus for many years research has been undertaken on the introduction into the backfill mixture of cheaper materials from available waste products. This paper presents the results of mixtures of backfill filling sand retrieved from the mine “Maczki-Bor”, using waste from energy production in the form of slag in compliance with PN-G/11010 “Hydraulic backfill materials”. The study made the following determinations: grain composition, washout ability, chemical composition and leaching of harmful substances, radioactivity, and compressibility. For this test, a mixture of sand with slag was used with a mass fraction of the slag amounting to 0.5, 10, 15, and 20%. Based on the performed tests, it can be concluded that the test material, the sand and slag and their mixtures, meet the standard requirements, and may be applied to the hydraulic backfill. The use of energetic slag as a component of the backfill mixture also has a positive ecological aspect contributing to the environment by reducing its storage elsewhere

Analysis of physico-mechanical properties of hydromixtures prepared based on ashes from fluidized bed boilers regarding possibilities of liquidation of the underground excavations and cavities

W polskich kopalniach węgla kamiennego od wielu lat z powodzeniem wykorzystywane są drobnofrakcyjnej odpady energetyczne w postaci zawiesin popiołowo-wodnych. Przykładem takich odpadów są popioły z kotłów fluidalnych posiadające własności pucolanowe pozwalające na wykorzystanie ich do wypełniania wybranych wyrobisk i pustek podziemnych materiałem o wymaganych parametrach wytrzymałościowych. Z uwagi na różnice własności fizycznych różnych popiołów fluidalnych, w artykule przedstawiono wyniki badań hydromieszanin wykonanych na bazie popiołów fluidalnych z trzech wybranych zakładów energetycznych.For many years in Polish coal mines there are succesfully used fine grade energy waste in form of ashed or water suspension, which are transported to selected places using pipelined gravity installations. One of this waste are ashes from fluidized boilers. Due to the pozzolanic properties, fly ashes can be used in mining technologies, which require filling selected underground cavities with material with required strength. According to some differences in physical properties of ashes, in this paper there are presented the results of hydromixtures’ researches made on the basis of the ashes in the three electricity boards

Optymalizacja składu hydromieszaniny popiołowo-wodnej pod kątem minimalizacji wody nadmiarowej i możliwości hydrotransportu grawitacyjnego do wyrobisk podziemnych

For years, the Polish hard coal mining has been struggling with the problem of fire hazards in areas with coal residue, mainly in goafs. Currently, a common method of limiting this hazard is the fire prevention involving use of fine-grained hydromixtures based on power generation waste, mainly fly ashes. The hydromixture is introduced into the caving zone created by the advancement of exploitation face and its task is to fill in voids, limiting the possibility of access to the mine air oxygen to a minimum. The first part of the article presents theoretical fundamentals of determining the parameters of gravitational hydraulic transport of water and ash hydromixtures used in the mining pipeline systems. Each hydromixture produced based on fine-grained wastes is characterized by specified rheological parameters that have a direct impact on the future flow parameters of a given pipeline system. Additionally, the gravitational character of the hydraulic transport generates certain limitations concerning the so-called correct hydraulic profile of the system in relation to the applied hydromixture characterized by required rheological parameters that should ensure safe flow at a correct efficiency. This paper shows an example of optimisation of the composition of a selected fly ash-water hydromixture in relation to its capacity for hydrotransport in gravity pipeline installations, as well as the amount of excess water that will always drain from the location of feeding the hydromixture to the underground workings.Polskie górnictwo węgla kamiennego od lat boryka się z problematyką zagrożenia pożarowego powstającego w miejscach pozostawienia resztek węgla głównie w zrobach zawałowych. Obecnie powszechną metodą ograniczenia tego zagrożenia jest stosowanie profilaktyki pożarowej wykorzystującej hydromieszaniny drobnofrakcyjne wykonane na bazie odpadów energetycznych, głównie popiołów energetycznych. Hydromieszanina taka wprowadzana jest do przestrzeni zawałowej powstałej za postępem frontu eksploatacyjnego, a jej zadaniem jest wypełnienie wolnych przestrzeni przy ograniczeniu do minimum możliwości dostępu do tlenu z powietrza kopalnianego. W artykule w pierwszej części przedstawiono podstawy teoretyczne wyznaczania parametrów grawitacyjnego hydrotransportu hydromieszanin popiołowo-wodnych stosowanych w kopalnianych instalacjach rurociągowych. Każda hydromieszanina wykonana na bazie odpadów drobnofrakcyjnych charakteryzuje się określonymi parametrami reologicznymi, które mają bezpośredni wpływ na przyszłe parametry przepływu w danej instalacji rurociągowej. Dodatkowo charakter grawitacyjny hydrotransportu generuje jego ograniczenia związane z tzw. poprawnym profilem hydraulicznym instalacji w odniesieniu do zastosowanej hydromieszaniny o wymaganych parametrach reologicznych, które powinny zapewniać bezpieczeństwo przepływu z odpowiednią wydajnością. W artykule przedstawiono przykład optymalizacji składu wybranej hydromieszaniny popiołowowodnej z punktu widzenia możliwości jej hydrotransportu w grawitacyjnych instalacjach rurociągowych, a także ilości wody nadmiarowej, która zawsze będzie odciekać z miejsca podawania hydromieszaniny do wyrobisk podziemnych