An investigation of Nano-particle deposition in cylindrical tubes under Laminar condition using Lagrangian transport model

Aerosol deposition in cylindrical tubes is a subject of interest to researchers and engineers in many applications of aerosol physics and metrology. Investigation of nano-particles in different aspects such as lungs, upper airways, batteries and vehicle exhaust gases is vital due the smaller size, adverse health effect and higher trouble for trapping than the micro-particles. The Lagrangian particle tracking provides an effective method for simulating the deposition of nano-particles as well as micro-particles as it accounts for the particle inertia effect as well as the Brownian excitation. However, using the Lagrangian approach for simulating ultrafine particles has been limited due to computational cost and numerical difficulties. In this paper, the deposition of nano-particles in cylindrical tubes under laminar condition is studied using the Lagrangian particle tracking method. The commercial Fluent software is used to simulate the fluid flow in the pipes and to study the deposition and dispersion of nano-particles. Different particle diameters as well as different flow rates are examined. The point analysis in a uniform flow is performed for validating the Brownian motion. The results show good agreement between the calculated deposition efficiency and the analytic correlations in the literature. Furthermore, for the nano-particles with the diameter more than 40 nm, the calculated deposition efficiency by the Lagrangian method is less than the analytic correlations based on Eulerian method due to statistical error or the inertia effect.

Musculoskeletal disorders and psychosocial factors at work : Effects of a participatory ergonomics intervention in a cluster randomized controlled trial

This study examined the efficacy of a participatory ergonomics intervention in preventing musculoskeletal disorders (MSDs) and changing unsatisfactory psychosocial working conditions among municipal kitchen workers. The occurrence of multiple-site musculoskeletal pain (MSP) and associations between MSP and psychosocial factors at work over time were studied secondarily. A cluster randomized controlled trial was conducted during 2002-2005 in 119 municipal kitchens with 504 workers. The kitchens were randomized to an intervention (n = 59) and control (n = 60) group. The intervention lasted 11 to 14 months. The workers identified strenuous work tasks and sought solutions for decreasing physical and mental workload. The main outcomes were the occurrence of and trouble caused by musculoskeletal pain in seven anatomical sites, local musculoskeletal fatigue after work, and musculoskeletal sick leaves. Psychosocial factors at work (job control, skill discretion, co-worker relationships, supervisor support, mental strenuousness of work, hurry, job satisfaction) and mental stress were studied as intermediate outcomes of the intervention. Questionnaire data were collected at three months intervals during the intervention and the one-year post-intervention follow-up. Response rates varied between 92 % and 99 %. In total, 402 ergonomic changes were implemented. In the control group, 80 changes were spontaneously implemented within normal activity. The intervention did not reduce perceived physical workload and no systematic differences in any health outcomes were found between the intervention and control groups during the intervention or during the one-year follow-up. The results suggest that the intervention as studied in the present trial was not more effective in reducing perceived physical workload or preventing MSDs compared with no such intervention. Little previous evidence of the effectiveness of ergonomics interventions in preventing MSDs exists. The effects on psychosocial factors at work were adverse, especially in the two of the participating cities where re-organization of foodservices timed simultaneously with the intervention. If organizational reforms at workplace are expected to occur, the execution of other workplace interventions at the same time should be avoided. The co-occurrence of musculoskeletal pain at several sites is observed to be more common than pain at single anatomical sites. However, the risk factors of MSP are largely unknown. This study showed that at baseline, 73 % of the women reported pain in at least two, 36 % in four or more, and 10 % in six to seven sites. The seven pain symptoms occurred in over 80 different combinations. When co-occurrence of pain was studied in three larger anatomical areas (neck/low back, upper limbs, lower limbs), concurrent pain in all three areas was the most common combination (36 %). The 3-month prevalence of MSP (≥ 3 of seven sites) varied between 50 % and 61 % during the two-year follow-up period. Psychosocial factors at work and mental stress were strong predictors for MSP over time and, vice versa, MSP predicted psychosocial factors at work and mental stress. The reciprocality of the relationships implies either two mutually dependent processes in time, or some shared common underlying factor(s).

Drug cultures in Estonia : contexts, meanings and patterns of illicit drug use.

In Estonia, illicit drug use hardly existed before the social changes of the 1990s when, as a result of economic and cultural transformations, the country became part of a world order centred in the West. On the one hand, this development is due to the spread of international youth culture, which many young people have perceived as being associated with drugs; on the other hand, it results from the marginalisation of a part of the population. The empirical part of the study is based mostly on in-depth interviews with different drug users conducted during between 1998 and 2002. Complementary material includes the results of participant observations, interviews with key experts, and the results of previous quantitative studies and statistics. The young people who started experimenting with illicit drugs from the 1990s and onwards perceived them as a part of an attractive lifestyle - a Western lifestyle, a point which is worth stressing in the case of Estonia. Although the reasons for initiation into drug use were similar for the majority of young people, their drug use habits and the impact of the drug use on their lives began to differ. I argue that the potential pleasure and harm which might accompany drug use is offset by the meanings attached to drugs and the sanctions and rituals regulating drug use. In the study both recreational and problem use have been analysed from different aspects in seven articles. I have investigated different types of drug users: new bohemians, cannabis users, in whose case partying and restrictive drug use is positively connected to their lives and goals within established society; stimulant-using party people for whom drugs are a means of having fun but who do not have the same restrictive norms regulating their drug use as the former and who may get into trouble under certain conditions; and heroin users for whom the drug rapidly progressed from a means of having fun to an obligation due to addiction. The research results point at the importance not only of the drug itself and the socio-economic situation of the user, but also of the cultural and social context within which the drug is used. The latter may on occasions be a crucial factor in whether or not initial drug use eventually leads to addiction.

Sukupuolen rakentuminen väkivaltakertomuksissa

Tutkielmassa tarkasteltiin sukupuolen sosiaalista rakentumista väkivaltaa käsittelevissä kertomuksissa. Aineistona oli 31 lehti-ilmoituksella kerättyä väkivaltakertomusta, joissa väkivallasta kirjoitettiin sekä väkivallan uhrin että tekijän positiosta käsin. Tarkoituksena oli tutkia, millä tavoin väkivaltaa konstruoidaan kertomuksissa ja miten tämä yhdistyy kirjoittajien sukupuolen suorittamiseen. Analyysimenetelmänä oli diskurssianalyysi, jossa sovellettiin sekä poststrukturalistisen diskurssianalyysin että diskursiivisen psykologian lähestymistapaa. Aineistosta oli löydettävissä yhteensä yhdeksän erilaista väkivaltakonstruktiota. Miehen toiseen mieheen kohdistaman väkivallan kontekstissa väkivaltaa konstruoitiin kolmessa konstruktiossa oikeutetuksi ja kahdessa paheksuttavaksi. Parisuhdeväkivallan ja perheessä lapsiin kohdistuvan väkivallan kontekstissa väkivalta näyttäytyi joko väkivallan tekijään liittyvänä, valta-aseman vahvistamisena tai osapuolten vuorovaikutukseen liittyvänä. Tämän lisäksi kaikissa konteksteissa väkivaltaa konstruoitiin toisinaan väkivallan tekijän ulkoisista syistä aiheutuvaksi. Sukupuolen suorittaminen käsitettiin tutkielmassa asemointipyrkimyksinä sukupuolen mukaisiin subjektipositioihin. Kirjoittajien katsottiin kohtaavan väkivaltaan ja sukupuoleen liittyviä diskursiivisia ristiriitoja, joita he pyrkivät neuvottelemaan käyttäen erilaisia neuvottelustrategioita. Väkivaltaan ja maskuliinisuuteen liittyviä diskursiivisia ristiriitoja pyrittiin neuvottelemaan sosiaalisen paheksunnan välttämiseen ja maskuliinisuuden todistamiseen käytetyillä neuvottelustrategioilla. Uhriuteen ja feminiinisyyteen liittyviä diskursiivisia ristiriitoja neuvoteltiin uhriuden todistamiseen sekä sille vastakohtaisesti uhriuden välttelyyn käytetyillä neuvottelustrategioilla, joiden tulkittiin liittyvän pyrkimyksiin asemoitua vahvan naisen positioon. Keskeisinä neuvottelustrategioina olivat erilaiset eronteot, esimerkiksi oikeutetun ja paheksuttavan väkivallan välille, uhrin ja tekijän välille sekä itsen välille ennen ja nyt. Tärkeimmät tutkielmassa käytetyt lähteet olivat: Burr, Vivien (1995): An Introduction to Social Constructionism; Butler, Judith (1990): Gender Trouble. Feminism and the Subversion of Identity; Harré, Rom & van Langenhove, Luk (toim.) (1999): Positioning Theory: Moral Contexts of Intentional Action; Hearn, Jeff (1998): The Violences of Men. How Men Talk about and How Agencies Respond to Men’s Violence to Women; Jokinen, Arto (2000): Panssaroitu maskuliinisuus. Mies, väkivalta ja kulttuuri; Keskinen, Suvi (2005): Perheammattilaiset ja väkivaltatyön ristiriidat; Ronkainen, Suvi & Näre, Sari (toim.) (2008): Paljastettu Intiimi. Sukupuolistuneen väkivallan dynamiikka; Wetherell, Margaret (1998): Positioning and Interpretative Repertoires: Conversation Analysis and Post-Structuralism in Dialogue. Avainsanat – Nyckelord – Keywords sukupuolen rakentuminen, väkivalta, subjektipositiot, diskurssianalyysi, diskurssit