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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

VIBRAÇÕES EM UM TRATOR AGRÍCOLA CABINADO: MAGNITUDE DAS ACELERAÇÕES NO ASSENTO E TRANSMISSIBILIDADE ATRAVÉS DO COXIM / VIBRATIONS ON AN AGRICULTURAL TRACTOR WITH A CABIN: MAGNITUDE OF ACCELERATIONS ON THE SEAT AND TRANSMISSIBILITY THROUGH THE RUBBER GROMMET

Pinho, Marivan da Silva 19 October 2012 (has links)
The tractor is the machines that provides the largest percentage of power used on rural activities inside the agricultural automation, making the researches on parameters of the vibration frequency on the rubber grommet and the tridimensional magnitude more convenient, in order to contribute to the future engineering researches. Therefore, this work has the main objective to analyze the magnitude of efficient accelerations on the seat-operator interface and the vibrations transmissibility of the rubber grommet on the agricultural tractor with a cabin, using three adjustment knob positions, two scarification depths, two displacement speeds and three different ballast settings. The experiment was held at the Phytotechny School s experimental area (Federal University of Santa Maria) through a subdivided portion outlining with 4 repetitions and 144 experimental units. A 4x2 TDA tractor was used with 63 kW of power on the engine (63 kW) attached to the chisel plow. The information was recorded by the accelerometers that were installed on the floor of the cabin, platform, rubber grommet and on the seat. It was concluded that the magnitude of efficient accelerations obtained on the seat-operator interface in all the 36 individual tests stayed above the comfort limit on the frequency of 1 to 80Hz, established by the standard (ISO 2631-1: 1997) for daily 8-hour exposure. The magnitude of efficient accelerations on the vertical direction (z) in the tractor s cabin floor in all the 36 individual tests had comfortable rates for the total metallic ballasting (TMB) and little uncomfortable for both the partial metallic ballasting (PMB) and the total hydraulic ballasting (THB) according to the (ISO 2631-1: 1997). The vibration transmissibility, on the direction (z) through the rubber grommet, had an amplification in the interval from 0 to 15Hz for TMB, from 0 to 19Hz for PMB and from 71 to 76Hz for THB. The transmissibility rates in the analysis between 1 and 80 Hz corresponded to 59%, 74% and 88% for TMB, PMB and THB, respectively. In all the individual tests, the vibration transmissibility from the floor to the seat was around twenty times higher compared to the vibration transmissibility from the platform to the tractor floor, using the frequency range from 1 to 80 Hz. On the virtual dynamic simulation, the elastomer provided around 11% reduction for the vibration magnitude on the seat-operator interface in the vertical direction. / O trator é uma das máquinas que fornece a maior parte da potência para execução das atividades rurais dentro da mecanização agrícola, sendo oportunas maiores investigações dos parâmetros de frequência da vibração nos coxins e magnitudes tridimensionais no assento, a fim de contribuir para futuras pesquisas de engenharia. Sendo assim, este trabalho teve por objetivo analisar as magnitudes das acelerações eficazes na interface assento-operador e a transmissibilidade das vibrações no coxim de um trator agrícola cabinado, utilizando três posições de regulagem do assento, duas profundidades de escarificação, duas velocidades de deslocamento e três configurações de lastros. O experimento foi realizado na Universidade Federal de Santa Maria com delineamento de parcelas subdivididas, com 4 repetições, totalizando 144 unidades experimentais. Utilizou-se um trator, (4x2 TDA) com potência no motor de 63 kW (85 cv), tendo um escarificador acoplado, os dados foram registrados através de acelerômetros instalados no piso da cabina, na plataforma, no coxim e no assento. Concluiu-se que as magnitudes das acelerações eficazes obtidas, na interface assento-operador, em todos os 36 tratamentos, ficaram acima do limite de conforto na frequência de 1 a 80 Hz, estabelecidas pela norma (ISO 2631-1: 1997) para exposição de 8h diária do operador. As magnitudes das acelerações eficazes na direção vertical (z), no piso da cabina do trator, em todos os 36 tratamentos, tiveram índice confortável para a lastragem metálica total (LMT) e pouco desconfortável para a lastragem metálica parcial (LMP) e lastragem hidráulica total (LHT), de acordo com a (ISO 2631-1: 1997). A transmissibilidade de vibração na direção (z) através do coxim teve amplificação no intervalo de 0 a 15 Hz para a LMT, de 0 a 19 Hz para a LMP e de 71 a 76 Hz para a LHT. Os valores de transmissibilidade na análise de 1 a 80 Hz corresponderam a 59%, 74% e 88%, respectivamente para a LMT, LMP e LHT. Em todos os tratamentos a transmissibilidade de vibração do piso para o assento foi em torno de 20 vezes maior em relação à transmissibilidade da plataforma para o piso do trator, sendo a faixa frequência de 1 a 80 Hz. Na simulação dinâmica virtual, o elastômero utilizado proporcionou uma redução da magnitude de vibração na interface assento-operador, em torno de 11%, na direção vertical.
2

The Long Term Effects of the Fluctuating, Conductive Hearing Loss Caused by Otitis Media with Effusion on Learning and Behaviour for Adolescent Students

Stenton, Janice, n/a January 2004 (has links)
Children frequently experience fluctuating conductive hearing loss during and following episodes of otitis media with effusion. With the prevalence of the disease increasing in the non-Aboriginal population in Australia, many children may be at risk of long-term learning and behavioural problems. There are conflicting findings in the research literature regarding the effects of this type of hearing loss. Although it is expected that the insertion of tympanostomy tubes (grommets) will reduce the duration and prevalence of both the disease and the conductive hearing loss, this does not always happen. For some primary school aged children it appears that experience with otitis media with effusion with or without grommet insertion is associated with various education problems including poor academic achievement and inappropriate behaviour. A current concern is whether or not these possible effects would continue to influence the learning and behaviour of children as they continue into their high school years. A review of the literature suggests that multiple factors including interrelationships between experience of otitis media with effusion, family and childcare environments may be involved in explaining why some students do not achieve as expected at school (Roberts et al., 2000). The literature further suggests there may be a cumulative effect in these factors, which introduces both quantitative and qualitative aspects to the discussion. A study was undertaken to identify the impact of otitis media with effusion and its associated sequelae on the learning and behaviour of high school students. Information from parents of high school students in Years 8 and 9 was used to identify students for inclusion in the study and to provide information on their medical and educational history as well as the parents' perceptions of various aspects of the students' learning and behaviour (including social skills). Three groups were formed: a Non-OME/Non-Grommet Group (n = 28), an OME/Grommet Group (n = 17) and an OME/Non-Grommet Group (n = 32). The TORCH, WRAT 3 and the Test of Syntactic Abilities (Screening Test) were administered to the students who also provided their own perceptions of specific aspects of their own learning and behaviour on a survey form. Teachers' perceptions on these areas were also collected. School academic records as well as data from school behavioural records were used. Analysis of the results revealed a range of mild effects. These included poorer academic results particularly for girls with a history of grommets, who also exhibited a lack of confidence in their social skills. An increase in behaviour problems for boys with a history of the disease (with or without grommets) was also found. The study identifies a number of associated teaching and learning issues including noise levels in childcare environments and school classrooms, current teaching and learning methodology and the training of new teachers. It recommends a number of areas for future research including more in-depth questioning of parents regarding their awareness of hearing problems in their children, the use of more fine-grained measures to assess learning outcomes and the identification of possible gender differences associated with the disease and experiences with grommets.
3

Hå och hamna : Ordhistoriska och ordgeografiska studier av paddlingens och roddens äldsta terminologi i Norden

Sandström, Åke January 2015 (has links)
In Old West Norse there is mention of an Arctic skin and osier boat, which was paddled with Old West Norse (húð)keipr, diminutive keipull, formed on Germanic *kaip- ’bend, unfold’ according to the construction method. In East Norse there was a corresponding wooden boat, e.g. Swedish själ-myndrick, formed on mynda verb ‘paddle’ (&lt; Primitive Norse *mundian ‘aim at a certain goal, take aim’). In the provinces south of this verb’s area of distribution there occurs instead svepa verb ’paddle’ (&lt; Primitive Germanic *swaipōn ‘swing’). The earliest instances of Nordic rowing navigation are found in Norway and Denmark. Instances of rowing in the Baltic area are found on some picture stones from about the 6th century. But oarlocks with a grommet were probably used already for the steering oar in the paddled boats of the Bronze Age. An early oarlock (with a grommet) is that made of a goose-necked piece of wood, Old Swedish hār, Old West Norse hár (&lt; *hanhu-, *hanha- ‘branching, fork of a branch’) and Old West Norse keipr (&lt; *kaip- ‘something with a crooked or bent (-back) shape’. The word hár exists as a first element in Old Swedish hā-band ‘oar-loop’, Old West Norse há-bora ‘oar-port’ etc. Old West Norse keipr ‘oarlock’ has no ancient compounds. East Nordic hamna (&gt; Finnish hamina), Old Danish hafnæ (Old Frisian hevene) and West Nordic hamla (Faroese homla, Old English hamele, hamule) ‘oar-loop’ occurred early on the oarlock with a grommet; hamna may be a derivation of the stem in Primitive Norse *haƀan verb ‘hold (fast)’, alternatively *hafna- ‘clasp something’; hamla derives from a Germanic *hamilōn with the meaning ‘bridling band’. Centrally in the Nordic area hamna (Danish havne) and hamla ‘oar-loop’ were also used denominatively with the meaning ‘row pushing in a hamna/hamla (oar-loop)’. In addition there is the Swedish dialectal sväva (~ sveva, svävja) ‘row (back, break etc.) with pushing rowing’ and in the group of older verbs for rowing there is East Swedish hopa &lt; Primitive Norse *hōƀian ‘fix one’s eyes upon a certain goal (in the distance)’. With word formations on Germanic *þulna- ‘wooden plug’ there arose from the Middle Ages and in the North Sea countries a new terminology for the oarlock: Norse tull, toll ‘oarlock with a thole pin’. Even younger concepts are tullgång ‘oarlock with two thole pins’, årklyka, årgaffel ‘oar crutch’. A distinctive trait of Old Swedish hār and hamna, Old West Norse hár and hamla and keipr and other common words for the oarlock is in these words the shift of meaning ‘oarlock of a specific kind’ &gt; ‘almost any kind of oarlock’. Finally, the question arises whether or not the word svear of a tribe by Lake Mälaren could be tied to the paddling through a connection to the stem of the verbs svepa and sväva. / <p>Ingår även i serie: Studier till en svensk dialektgeografisk atlas, 8</p>
4

A program to prepare children for grommet insertion and adenoidectomy : a Gestalt therapy approach

Birkenstock, Jeannette Dorothy 30 November 2005 (has links)
The aim of this study was to develop a Gestalt play therapy based hospital preparation program for children undergoing the surgical procedures of grommet insertion, or grommet insertion and adenoidectomy, at Tygerberg Hospital. Literature was reviewed according to relevant topics, namely otitis media in children, Gestalt play therapy, theories of child development, and children's experience of illness and hospitalisation. Semi-structured interviews were conducted with four subject groups and the data obtained was qualitatively analysed. Research findings were discussed and integrated with reference to the literature. This information was applied in the development of the proposed program. The aim, underlying principles, objectives and components of the program were discussed and guidelines for implementation were provided. The program was implemented and evaluated in a single subject pilot study, which yielded a positive response. Recommendations for both practical implementation in a therapeutic context and further study in a research context were made. OPSOMMING Die doel van hierdie studie was om `n Gestalt spelterapie-gebaseerde hospitaalvoorbereidingsprogram te ontwikkel vir kinders wat die chirurgiese prosedures van ventilasiebuis-plasing of ventilasiebuis-plasing en adenoïdektomie by Tygerberg-hospitaal ondergaan. `n Literatuurstudie is uitgevoer rakende relevante onderwerpe; naamlik, otitis media in kinders, Gestalt spelterapie, kinderontwikkelingsteorieë, en kinders se ervaring van siekte en hospitalisasie. Semi-gestruktureerde onderhoude is met vier subjekgroepe uitgevoer en die data wat verkry is, is kwalitatief geanaliseer. Navorsingsbevindinge is bespreek en geïntegreer met verwysing na die literatuur. Hierdie inligting is toegepas in die ontwikkeling van die voorgestelde program. Die doel, onderliggende beginsels, doelstellings en komponente van die program is bespreek en riglyne vir die implementering daarvan is verskaf. Die program is geïmplimenteer en geëvalueer in `n enkelsubjek loodsstudie, waar `n positiewe respons verkry is. Aanbevelings vir beide praktiese implementering in `n terapeutiese konteks en verdere studie binne navorsingskonteks is gemaak. / Social Work / M.Diac.
5

A program to prepare children for grommet insertion and adenoidectomy : a Gestalt therapy approach

Birkenstock, Jeannette Dorothy 30 November 2005 (has links)
The aim of this study was to develop a Gestalt play therapy based hospital preparation program for children undergoing the surgical procedures of grommet insertion, or grommet insertion and adenoidectomy, at Tygerberg Hospital. Literature was reviewed according to relevant topics, namely otitis media in children, Gestalt play therapy, theories of child development, and children's experience of illness and hospitalisation. Semi-structured interviews were conducted with four subject groups and the data obtained was qualitatively analysed. Research findings were discussed and integrated with reference to the literature. This information was applied in the development of the proposed program. The aim, underlying principles, objectives and components of the program were discussed and guidelines for implementation were provided. The program was implemented and evaluated in a single subject pilot study, which yielded a positive response. Recommendations for both practical implementation in a therapeutic context and further study in a research context were made. OPSOMMING Die doel van hierdie studie was om `n Gestalt spelterapie-gebaseerde hospitaalvoorbereidingsprogram te ontwikkel vir kinders wat die chirurgiese prosedures van ventilasiebuis-plasing of ventilasiebuis-plasing en adenoïdektomie by Tygerberg-hospitaal ondergaan. `n Literatuurstudie is uitgevoer rakende relevante onderwerpe; naamlik, otitis media in kinders, Gestalt spelterapie, kinderontwikkelingsteorieë, en kinders se ervaring van siekte en hospitalisasie. Semi-gestruktureerde onderhoude is met vier subjekgroepe uitgevoer en die data wat verkry is, is kwalitatief geanaliseer. Navorsingsbevindinge is bespreek en geïntegreer met verwysing na die literatuur. Hierdie inligting is toegepas in die ontwikkeling van die voorgestelde program. Die doel, onderliggende beginsels, doelstellings en komponente van die program is bespreek en riglyne vir die implementering daarvan is verskaf. Die program is geïmplimenteer en geëvalueer in `n enkelsubjek loodsstudie, waar `n positiewe respons verkry is. Aanbevelings vir beide praktiese implementering in `n terapeutiese konteks en verdere studie binne navorsingskonteks is gemaak. / Social Work / M.Diac.

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