Ash agglomeration and deposition during combustion of poultry litter in a bubbling fluidized-bed combustor

peer-reviewedn this study, we have characterized the ash resulting from fluidized bed combustion of poultry litter as being dominated by a coarse fraction of crystalline ash composed of alkali-Ca-phosphates and a fine fraction of particulate K2SO4 and KCl. Bed agglomeration was found to be coating-induced with two distinct layers present. The inner layer (0.05–0.09 mm thick) was formed due to the reaction of gaseous potassium with the sand (SiO2) surface forming K-silicates with low melting points. Further chemical reaction on the surface of the bed material strengthened the coating forming a molten glassy phase. The outer layer was composed of loosely bound, fine particulate ash originating from the char. Thermodynamic equilibrium calculations showed slag formation in the combustion zone is highly temperature-dependent, with slag formation predicted to increase from 1.8 kg at 600 °C to 7.35 kg at 1000 °C per hour of operation (5.21 kg of ash). Of this slag phase, SiO2 and K2O were the dominant phases, accounting for almost 95%, highlighting the role of K-silicates in initiating bed agglomeration. The remaining 5% was predicted to consist mainly of Al2O3, K2SO4, and Na2O. Deposition downstream in the low-temperature regions was found to occur mostly through the vaporization–condensation mechanism, with equilibrium decreasing significantly with decreasing temperatures. The dominant alkali chloride-containing gas predicted to form in the combustion zone was KCl, which corresponds with the high KCl content in the fine baghouse ash

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Characteristics of being hospitalized as a child with a new diagnosis of type 1 diabetes: a phenomenological study of children’s past and present experiences.

Background Our understanding of children and childhood has changed over the last few decades, which may have an impact on children’s conditions in hospitals. Children’s rights have been strengthened by the “Convention on the Rights of the Child” and ward regulations. The aim of this Norwegian study was to identify potential characteristics of children's lived experience of being hospitalized diagnosed with type 1 diabetes today and from a retrospective view in the period 1950–1980, despite the many obvious external changes. Methods This study presents a further analysis of data from two previous phenomenological studies. The first had a retrospective perspective, and the second assumed a contemporary perspective. Twelve adults and nine children who had been hospitalized for newly diagnosed type 1 diabetes at the age of approximately 6–12 years old participated. The adults relayed narratives from their childhood memories through interviews, and the study with the children was designed as a combination of observations, in-depth interviews, and photographs. A hermeneutic phenomenological method was used in the analysis. Results The analysis revealed a meaning structure that described a tension between vulnerability and agency in the experiences of being hospitalized as a child, both past and present. The experiences may further be characterized as alienation versus recognition and as passivity versus activity, relating to both the hospital environment and the illness. Conclusions To a greater extent than ever, children today tend to experience themselves as active and competent individuals who can manage their own illness. Previously, children seemed to experience themselves as more vulnerable and less competent in relationship to their environment and illness. Presently, as before, children appear to desire involvement in their illness; however, at the same time, they prefer to share responsibility with or hand over responsibility to adults. However, living with diabetes was and remains demanding, and it affects children’s lifeworld. Balancing the children’s vulnerability and agency seems to be the best way to care for children in hospitals. In this article, we thus argue for a lifeworld-led approach when caring for hospitalized children, paying attention to both their vulnerability and agency

Transactive Teaching in a Time of Climate Crisis

This article discusses three problems that need to be tackled when the climate crisis becomes 'a sustainability issue' to be taught in schools. The article highlights, first, how knowledge concerning sustainability in schools risks being reduced and made into knowledge about 'things'. Secondly, it also discusses how students in such a context risk being treated as instruments for ways of being in the world, rather than being subjects with ethical and political concerns for the world in which they live 'here and now'. Thirdly, as we explore through some empirical examples, such reduction and instrumentalism objectifies both students and nature, which makes an adequate response to the crises obsolete. As an alternative, the article develops a notion of grievability and its importance for adequately responding to all living beings within a project of sustainability. To this end, it develops suggestions for a transactive teaching approach in a time of climate crisis