A liberation model for comminution based on probability theory

Mineral processing plants use two main processes; these are comminution and separation. The objective of the comminution process is to break complex particles consisting of numerous minerals into smaller simpler particles where individual particles consist primarily of only one mineral. The process in which the mineral composition distribution in particles changes due to breakage is called 'liberation'. The purpose of separation is to separate particles consisting of valuable mineral from those containing nonvaluable mineral. The energy required to break particles to fine sizes is expensive, and therefore the mineral processing engineer must design the circuit so that the breakage of liberated particles is reduced in favour of breaking composite particles. In order to effectively optimize a circuit through simulation it is necessary to predict how the mineral composition distributions change due to comminution. Such a model is called a 'liberation model for comminution'. It was generally considered that such a model should incorporate information about the ore, such as the texture. However, the relationship between the feed and product particles can be estimated using a probability method, with the probability being defined as the probability that a feed particle of a particular composition and size will form a particular product particle of a particular size and composition. The model is based on maximizing the entropy of the probability subject to mass constraints and composition constraint. Not only does this methodology allow a liberation model to be developed for binary particles, but also for particles consisting of many minerals. Results from applying the model to real plant ore are presented. A laboratory ball mill was used to break particles. The results from this experiment were used to estimate the kernel which represents the relationship between parent and progeny particles. A second feed, consisting primarily of heavy particles subsampled from the main ore was then ground through the same mill. The results from the first experiment were used to predict the product of the second experiment. The agreement between the predicted results and the actual results are very good. It is therefore recommended that more extensive validation is needed to fully evaluate the substance of the method. (C) 2003 Elsevier Ltd. All rights reserved.

Simple texture-based liberation modelling of ores

Mineralogical analysis is often used to assess the liberation properties of particles. A direct method of estimating liberation is to actually break particles and then directly obtain liberation information from applying mineralogical analysis to each size-class of the product. Another technique is to artificially apply random breakage to the feed particle sections to estimate the resultant distribution of product particle sections. This technique provides a useful alternative estimation method. Because this technique is applied to particle sections, the actual liberation properties for particles can only be estimated by applying stereological correction. A recent stereological technique has been developed that allows the discrepancy between the linear intercept composition distribution and the particle section composition distribution to be used as guide for estimating the particle composition distribution. The paper will show results validating this new technique using numerical simulation. (C) 2004 Elsevier Ltd. All rights reserved.

Secretoneurin is released into human airways by topical histamine but not capsaicin

Background: The neuropeptide secretoneurin, with potential relevance to leukocyte trafficking, is present in nerves of the nasal mucosa in allergic rhinitis and may be released in response to allergen and histamine exposure. There is no information on the occurrence and mechanisms of release of secretoneurin in healthy human airways. Methods: The presence of secretoneurin in nasal biopsies and its release in response to nasal capsaicin and histamine challenges were examined. Symptoms and lavage fluid levels of fucose were recorded as markers of effects in part produced by neural activity. Bronchial histamine challenges followed by sputum induction and analysis of secretoneurin were also carried out. Results: Nerves displaying secretoneurin immunoreactivity abounded in the nasal mucosa. Nasal capsaicin challenge produced local pain (P < 0.05) and increased the levels of fucose (P < 0.05), but failed to affect the levels of secretoneurin. Nasal histamine challenge produced symptoms (P < 0.05) and increased the mucosal output of secretoneurin (P < 0.05) and fucose (P < 0.05). Bronchial histamine challenge increased the sputum levels of secretoneurin (P < 0.05). Conclusions: We conclude that secretoneurin is present in healthy human airways and that histamine evokes its release in both nasal and bronchial mucosae. The present observations support the possibility that secretoneurin is involved in histamine-dependent responses of the human airway mucosa.

Waking the sleeping giant: Beliefs of Brazilian and *American teachers concerning liberation curriculum

The school curriculum is a matter mandated by the educational system rather than determined by the school stakeholders of a community, as Freire (1993) suggests. At the present time, one significant vision of school is challenging the current order of curriculum practice. It focuses on school as a liberating agency grounded on the belief that the abilities to access information and to think critically about it will educate an individual capable of making independent decisions. This dissertation investigates teacher's beliefs concerning curriculum. It was assumed that there is a discrepancy between what has been the position proposed by critical theorists including Freire (1998a, 1993); Apple (1979); Giroux (1998), and the position on curriculum which school systems are typically advancing. ^ There were four purposes of this study. The major purpose of this study was to determine whether or not Brazilian and American Teachers believe that a school curriculum based on Freirean principles could be implemented in the schools in which they worked. Also, this study sought to determine the differences found between teachers' beliefs in the Brazilian and American contexts. Another purpose was to determine how Brazilian and American teachers justify their beliefs and actions when these may represent conflicting values. Finally, this study sought to determine if these teachers believe that the curriculum is in need of change or if they accept the current curriculum as adequate. This study consisted of quantitative and qualitative data collection through multiple methods involving surveys and interviews. The study involved 171 teachers (88 Brazilian and 83 American) from multiple settings with the majority working for public systems. Overall, it seems that Brazilian and American teachers believe that a curriculum based on Freirean principles of education can be implemented in their schools, if ongoing education is provided. The majority of Brazilian teachers believe a curriculum change is necessary while half of the American teachers believe a curriculum change is needed and the other half seems to believe curriculum is adequate. Teachers explain that it is hard to implement a curriculum they believe to be most appropriate for students because the current curriculum is mandated by the school system or by national guidelines. The majority of Brazilian teachers and those American teachers who believed a curriculum change is necessary explained their rationale for change in terms of social justice, problem-solving, collective work, student-centered and context-based curriculum. American teachers, who believed that the curriculum is adequate, explained that they are satisfied with their student's achievements. They stated that their students are doing well on tests and are learning what is required. ^

Men's liberation demonstration

General note: Title and date provided by Bettye Lane.

Warren Farrell at Men's liberation demonstration

General note: Title and date provided by Bettye Lane.

Men's liberation demonstration during Women's March at Battery Park

General note: Title and date provided by Bettye Lane.

Men's liberation demonstration at The Playboy Club

General note: Title and date provided by Bettye Lane.

Men's liberation demonstration

General note: Title and date provided by Bettye Lane.