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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.
251

NOUVELLES MÉTHODES D'IDENTIFICATION D'ONDES DE SURFACE - ÉTUDE DE L'ONDE A SUR UNE CIBLE COURBE

Loïc, Martinez 29 January 1998 (has links) (PDF)
Le problème de la propagation d'ondes sur une plaque plane élastique en contact avec deux liquides différents est traité. Une étude numérique détaillée montre les propriétés de l'onde A et l'existence d'une nouvelle onde (onde A*) quand deux fluides différents sont en contact avec la lame. Une étude expérimentale des ondes A et A* est ensuite menée en utilisant des techniques expérimentales particulières à la caractérisation de l'onde A: génération d'une onde non atténuée par une impulsion et caractérisation par analyse temps-fréquence. La propagation d'une onde dans un milieu monodimensionnel infini est ensuite étudiée en utilisant les espaces de Fourier bidimensionnels. Un soin particulier est accordé à l'étude d'une onde atténuée et dispersive générée à partir d'une impulsion brève. Un nouveau lien est alors mis en évidence entre le vecteur d'onde complexe et la pulsation complexe. Ce lien autorise ainsi, et pour la première fois, une caractérisation complète des représentations toutfréquence et vecteur d'onde-temps. Sur la base de ces résultats, deux aspects sont développés: d'une part la modélisation de la propagation d'une onde autour d'un tube immergé (milieu monodimentionnel limité) et d'autre part de nouvelles méthodes de traitement du signal. L'aspect résonant dû à la propagation sur un tube d'une onde générée par une impulsion est ainsi montré et modélisé. De nouvelles méthodes de caractérisation d'ondes de surface sont mises en place, permettant de mesurer vecteur d'onde et pulsation complexes, sur des distances très courtes de l'ordre de quelques longueurs d'ondes. En utilisant ces nouveaux outils, la propagation de l'onde A est étudiée expérimentalement sur un tube immergé dans l'eau. L'influence des paramètres géométriques du tube ainsi que de son remplissage est étudiée. De nouveaux phénomènes sont mis en évidence lorsque le liquide intérieur possède une vitesse de propagation du son inférieure à celle du liquide externe, l'onde A* est observée périodiquement spatialement. On montre que la représentation tout fréquence correspondant à la somme de tous ces échos est le produit de convolution de la représentation tout fréquence de l'onde A* seule avec un résonateur de Fabry-Perot. Ce modèle expérimental est en bon accord avec les résultats théoriques.
252

Showmanship of Project Animals

Sprinkle, Jim, Fish, Dean 03 1900 (has links)
8 pp. / Information to help reduce the occurrence of show ring fiascos. Focus is on proper preparation, selection, and the necessary time commitment that youth participants can expect.
253

Produção de leite de ovelhas da raça Santa Inês e mestiças F1 e desempenho de suas progênies resultantes do cruzamento com carneiros da raça Dorper / Milk yield of Santa Inês and crossbred ewes and performance of their progeny after mating with Dorper rams

Meneghini, Rafael Cedric Moller 18 June 2010 (has links)
Dois experimentos foram realizados para avaliar o desempenho de ovelhas Santa Inês e mestiças F1 com machos de raças de corte e de suas crias obtidas do cruzamento com carneiros da raça Dorper. No experimento 1, setenta e cinco borregas ( 15 da raça Santa Inês (SI), 15 ½Dorper + ½SI, 15 ½Ile de France + ½SI, 15 ½Suffolk + ½SI e 15 ½Texel + ½SI foram acasaladas com carneiros da raça Dorper e avaliadas quanto ao seu desempenho na parição e lactação. Foram avaliados o número de crias nascidas/fêmea parida, peso de nascimento, % de desmama, consumo de MS das ovelhas, produção e composição do leite, escore de condição corporal, concentração de ácidos graxos não-esterificados e desempenho das crias. A produção de leite foi estimada semanalmente, da segunda à oitava semana de lactação. Os cordeiros foram separados das mães as quais receberam, via endovenosa, 10 UI de oxitocina para permitir a ejeção do leite que foi removido por ordenha mecânica. Após 3h, o procedimento de ordenha foi repetido e a produção de leite foi registrada e uma amostra coletada para posterior determinação da composição. Ovelhas SI apresentaram maior (P<0,05) CMS relativo ao peso corporal do que ovelhas ½DO, ½IF e ½SK. Ovelhas ½DO produziram mais gordura, sólidos totais (ST) e leite corrigido para gordura (LCG) que ovelhas ½IF. Os teores de gordura e de ST no leite das ovelhas ½DO foram maiores (P<0,05) do que no das ½TX. Ovelhas ½TX desmamaram mais kg de cordeiros do que as SI (27,2 kg vs. 17,3 kg). Cordeiros ¼TX apresentaram GMD maior (P<0,05) que os ¾DO (283 g vs. 229 g). No experimento 2, foram avaliados o desempenho e a carcaça de cordeiros mestiços ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) confinados sendo alimentados com ração contendo 90% de concentrado e 10% de feno. Os cordeiros mestiços entraram no confinamento com idade inicial média de 75 dias. Não houve diferença entre as médias de idade ao abate, peso no início do confinamento, peso no abate, consumo de matéria seca, ganho de peso médio diário, eficiência alimentar, peso de carcaça quente, peso de carcaça fria, rendimento de carcaça quente, rendimento de carcaça fria, área de olho de lombo, espessura de gordura subcutânea, alturas torácicas interna e externa, perímetro e comprimento de pernil, espessura de parede corporal, pesos e rendimentos dos cortes cárneos comerciais. Cordeiros do genótipo ¾DO apresentam maior perda por resfriamento de carcaça que os do genótipo ½SI. Cordeiros do genótipo ¼SK apresentam maior comprimento de carcaça que os cordeiros mestiços ¼TX. / Two experiments were performed to evaluate the performance of Santa Inês and F1 crossbred ewes and their lambs obtained by mating the ewes to Dorper rams. In Experiment 1- Seventy-five ewe lambs (15 Santa Inês (SI), 15 ½Dorper+½SI, 15 ½Ile de France+½SI, 15 ½Suffolk+½SI e 15 ½Texel+½SI) were mated to Dorper rams and evaluated during lambing and lactation. Number of lambs born/ewe, birth weight, weaning %, ewess DMI, milk yield, milk composition, body condition score, non- esterified fatty acids and lamb performance were evaluated. Milk production was measured every 7 d, from the second to the eighth week of lactation. Ewes were separated from lambs, oxytocin (10 IU) was infused, i.v., to stimulate milk letdown, and ewes were mechanically milked. After 3 h, the procedure was repeated and milk production was recorded and a sample collected for milk composition analysis. SI ewes showed higher (P<0.05) DMI as % of BW when compared to ½DO, ½IF and ½SK. A higher milk fat, total solids and fat corrected milk was observed for ½DO than ½IF. ½TX ewes produced more kg of weaned lambs than SI (27.2 kg vs. 17.3 kg). ADG for ¼TX lambs was higher (P<0.05) than ¾DO (283 g vs.229 g). In Experiment 2 Forty-eight lambs were used to evaluate the performance and carcass traits. Crossbred lambs were: ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) feedloted and fed diets containing 90% concentrate and 10% hay. Lambs were housed individually and the slaughter target weight was 37 kg. Lambs were 75 days old at begining of the feedlot. There was no difference (P>0.05) on slaughter weight and age, starting weight at feedlot, dry matter intake (DMI), average daily gain (ADG), feed efficiency (FE), hot carcass weight, chilled carcass weight, dressing percentage, Longissimus muscle area, back fat, carcass measures and retail cuts yield. Lambs ¾DO had greater chilling losses when compared to ½SI. Lambs ¼SK showed greater carcass lenght when compared to ¼TX. Crossbred lambs evaluated showed similar performance (ADG, DMI, FE) and carcass characteristics except for carcass lenght. Crossbreeding meat type sheep is an interesting strategy to obtain lambs with desirable performance and carcass quality.
254

Produção de leite de ovelhas da raça Santa Inês e mestiças F1 e desempenho de suas progênies resultantes do cruzamento com carneiros da raça Dorper / Milk yield of Santa Inês and crossbred ewes and performance of their progeny after mating with Dorper rams

Rafael Cedric Moller Meneghini 18 June 2010 (has links)
Dois experimentos foram realizados para avaliar o desempenho de ovelhas Santa Inês e mestiças F1 com machos de raças de corte e de suas crias obtidas do cruzamento com carneiros da raça Dorper. No experimento 1, setenta e cinco borregas ( 15 da raça Santa Inês (SI), 15 ½Dorper + ½SI, 15 ½Ile de France + ½SI, 15 ½Suffolk + ½SI e 15 ½Texel + ½SI foram acasaladas com carneiros da raça Dorper e avaliadas quanto ao seu desempenho na parição e lactação. Foram avaliados o número de crias nascidas/fêmea parida, peso de nascimento, % de desmama, consumo de MS das ovelhas, produção e composição do leite, escore de condição corporal, concentração de ácidos graxos não-esterificados e desempenho das crias. A produção de leite foi estimada semanalmente, da segunda à oitava semana de lactação. Os cordeiros foram separados das mães as quais receberam, via endovenosa, 10 UI de oxitocina para permitir a ejeção do leite que foi removido por ordenha mecânica. Após 3h, o procedimento de ordenha foi repetido e a produção de leite foi registrada e uma amostra coletada para posterior determinação da composição. Ovelhas SI apresentaram maior (P<0,05) CMS relativo ao peso corporal do que ovelhas ½DO, ½IF e ½SK. Ovelhas ½DO produziram mais gordura, sólidos totais (ST) e leite corrigido para gordura (LCG) que ovelhas ½IF. Os teores de gordura e de ST no leite das ovelhas ½DO foram maiores (P<0,05) do que no das ½TX. Ovelhas ½TX desmamaram mais kg de cordeiros do que as SI (27,2 kg vs. 17,3 kg). Cordeiros ¼TX apresentaram GMD maior (P<0,05) que os ¾DO (283 g vs. 229 g). No experimento 2, foram avaliados o desempenho e a carcaça de cordeiros mestiços ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) confinados sendo alimentados com ração contendo 90% de concentrado e 10% de feno. Os cordeiros mestiços entraram no confinamento com idade inicial média de 75 dias. Não houve diferença entre as médias de idade ao abate, peso no início do confinamento, peso no abate, consumo de matéria seca, ganho de peso médio diário, eficiência alimentar, peso de carcaça quente, peso de carcaça fria, rendimento de carcaça quente, rendimento de carcaça fria, área de olho de lombo, espessura de gordura subcutânea, alturas torácicas interna e externa, perímetro e comprimento de pernil, espessura de parede corporal, pesos e rendimentos dos cortes cárneos comerciais. Cordeiros do genótipo ¾DO apresentam maior perda por resfriamento de carcaça que os do genótipo ½SI. Cordeiros do genótipo ¼SK apresentam maior comprimento de carcaça que os cordeiros mestiços ¼TX. / Two experiments were performed to evaluate the performance of Santa Inês and F1 crossbred ewes and their lambs obtained by mating the ewes to Dorper rams. In Experiment 1- Seventy-five ewe lambs (15 Santa Inês (SI), 15 ½Dorper+½SI, 15 ½Ile de France+½SI, 15 ½Suffolk+½SI e 15 ½Texel+½SI) were mated to Dorper rams and evaluated during lambing and lactation. Number of lambs born/ewe, birth weight, weaning %, ewess DMI, milk yield, milk composition, body condition score, non- esterified fatty acids and lamb performance were evaluated. Milk production was measured every 7 d, from the second to the eighth week of lactation. Ewes were separated from lambs, oxytocin (10 IU) was infused, i.v., to stimulate milk letdown, and ewes were mechanically milked. After 3 h, the procedure was repeated and milk production was recorded and a sample collected for milk composition analysis. SI ewes showed higher (P<0.05) DMI as % of BW when compared to ½DO, ½IF and ½SK. A higher milk fat, total solids and fat corrected milk was observed for ½DO than ½IF. ½TX ewes produced more kg of weaned lambs than SI (27.2 kg vs. 17.3 kg). ADG for ¼TX lambs was higher (P<0.05) than ¾DO (283 g vs.229 g). In Experiment 2 Forty-eight lambs were used to evaluate the performance and carcass traits. Crossbred lambs were: ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) feedloted and fed diets containing 90% concentrate and 10% hay. Lambs were housed individually and the slaughter target weight was 37 kg. Lambs were 75 days old at begining of the feedlot. There was no difference (P>0.05) on slaughter weight and age, starting weight at feedlot, dry matter intake (DMI), average daily gain (ADG), feed efficiency (FE), hot carcass weight, chilled carcass weight, dressing percentage, Longissimus muscle area, back fat, carcass measures and retail cuts yield. Lambs ¾DO had greater chilling losses when compared to ½SI. Lambs ¼SK showed greater carcass lenght when compared to ¼TX. Crossbred lambs evaluated showed similar performance (ADG, DMI, FE) and carcass characteristics except for carcass lenght. Crossbreeding meat type sheep is an interesting strategy to obtain lambs with desirable performance and carcass quality.
255

A Teologia do Cordeiro no Evangelho segundo João: Jo 1,29;19,34-36

Nascimento, Abimael Francisco do 16 December 2013 (has links)
Made available in DSpace on 2016-04-29T14:27:24Z (GMT). No. of bitstreams: 1 Abimael Francisco do Nascimento.pdf: 1108943 bytes, checksum: d31781f4fefa92202df2c102c8a9fb44 (MD5) Previous issue date: 2013-12-16 / This research was guided by the method of literature review, in order to answer the question put on the problem: Which is the relevance and which are the implications of the image of the lamb, attributed to Jesus in the Gospel of John? - This question raises some considerations, such as: the relevance occurs due to the formation of the community that is the basis of this Gospel, as to say, groups that formed the Johannine community, those of the first hour, knew the cultic life of the Israelite tradition and applied it to Jesus through the typology of the lamb. A second consideration is that the lamb was in the worship, either to Jews or Samaritans, an element very present, kept from thanksgiving to the atonement. However, their presence more fixed in memory was that linked to the night of the Exodus, in which God commanded to sacrifice a paschal lamb. This celebration reminded every year the divine intervention and cherished the hope of a new exodus, in which the people would be released from the judge of the empires. The third consideration is on the figure of the lamb and the prophetic tradition of the Second Isaiah, who had proposed a cultic replacement: now a servant, like a lamb, would be the atoning of the sins of the people ( cf. Is 53:7 ). The servant of Isaiah takes the atoning function, something that was reserved for sacrificial rituals. Now, the servant assumes this function. Given this, the salutation of John the Baptist to Jesus (cf. Jn 1:29 ) gains another dimension, but with the possibility of combining the two ideas, as to say, the greeting of the Batista seems to address both perspective of the Paschal Lamb as well as the Suffering Servant. So that the Johannine Jesus assumes the role of lamb, but no more a lamb only to Israel but to the whole world. With this, the salvation of the Lamb-Servant is universal. He plays the role of forgiving sins and to make passing to eternal life, since He reconciles the mankind to God through his blood. The greeting of John the Baptist in John 1:29, in principle shows somewhat understandable, however, from a theological journey that culminates on Golgotha, in John 19.34-36, it is understandable what John the Baptist had announced in the opening week of Jesus' activity. Now, in the Passion, the final Easter is accomplished, full forgiveness is given, through the voluntary surrender of the Lamb of God / Apresente pesquisa pautou-se pelo método de pesquisa bibliográfica, com o fim de responder à questão lançada sobre o problema: qual a relevância e implicações da imagem do cordeiro, atribuída a Jesus, no Evangelho segundo João?- Desta interrogação surgem algumas considerações, tais como: a relevância se dá em virtude da formação da comunidade que está na base deste Evangelho, isto é, os grupos que formaram a comunidade joanina, aqueles da primeira hora, conheciam a vida cultual da tradição israelita e a aplicaram a Jesus por meio da tipologia do cordeiro. Uma segunda consideração é que o cordeiro era no culto, seja para samaritanos ou para judeus, um elemento bastante presente, e cumpria desde a ação de graças até a expiação. No entanto, sua presença mais fixada na memória era aquela ligada à noite da saída do Egito, na qual Deus ordenou a imolação de um cordeiro pascal. Esta celebração lembrava, a cada ano, a intervenção divina e alimentava a esperança de um novo êxodo, que libertasse o povo do julgo dos impérios. A terceira consideração é sobre a figura do cordeiro e a tradição profética do Segundo Isaías, que havia proposto uma substituição cúltica: agora um servo, semelhante a um cordeiro, seria o expiador dos pecados do povo (cf. Is 53,7). O servo de Isaías assume a função expiatória, algo que era reservado a rituais de sacrifício. Agora, o servo assume esta função. Diante disto, a saudação de João Batista a Jesus (cf. Jo 1,29) ganha outra vertente, mas com a possibilidade de aliar as duas ideias, isto é, a saudação Batista parece contemplar, tanto a perspectiva de Cordeiro Pascal, como de Servo Sofredor. De modo que o Jesus joanino assume a função de cordeiro, mas, não mais um cordeiro somente para Israel, e sim para todo o mundo. Com isto, a salvação do Cordeiro-Servo é universal. Ele cumpre a função de perdoar os pecados e de fazer passar para a vida eterna, visto que reconcilia, com o seu sangue, a humanidade com Deus. A saudação de João Batista em Jo 1,29, a princípio se mostra pouco compreensível, no entanto, a partir de um percurso teológico que culmina no Gólgota, em Jo 19,34-36, faz-se compreensível o que João Batista havia anunciado na semana inaugural da atividade de Jesus. Agora, na Paixão, a Páscoa definitiva se realiza, o perdão pleno é dado, por meio da entrega voluntária do Cordeiro de Deus
256

O simbolismo do cordeiro na obra pictórica os noivos e os três músicos de Marc Chagall

Leite, Beatriz Mori 13 February 2015 (has links)
Made available in DSpace on 2016-03-15T19:43:02Z (GMT). No. of bitstreams: 1 Beatriz Mori Leite.pdf: 11444537 bytes, checksum: e2eb22df6a2e83e22a99a3a667d4ebd9 (MD5) Previous issue date: 2015-02-13 / This dissertation presents and analyses the symbol of Marc Chagall The bridegroom and the three musicians", dated in 1972. In this work the symbol is related to the idea of sacrifice as in the part of unconditional love. The analyses of this paint implied in the detailed studies of the artist s life with emphasis in his religious memory. Chagall was born in Russia, Jewish son lived in a traditional Judaic village, in 1887 had begun in the artistic world, in the early 20th century, in 1910, when moved to Paris. His use of symbols allows us to understand more properly his artistic production as well as his personal history. The aim of this study was to identify the relationship between the artist s work of art and the influence he suffered in culture through religious education. Therefore, this research has an interdisciplinary character and fits perfectly in the graduate program of Education, Art and History of Culture at the Mackenzie Presbyterian University. The main references refer to the theories proposed by Jean Paul Ronecker, when referring to the symbolism of the animal in the history of culture and art with contribution of Carl Gustav Jung through the book The man and your symbols . With Theoretical basis in the religious symbolism in the culture, involving Judaism and Christianity were also consulted Anatol Rosenfeld and the Brazilian philosopher Mario Ferreira dos Santos. From a methodological point of view, multiple paths were covered: visits to museums with exhibits of Chagall s works of arts in Brazil and France, as well as interviews with a French artist Jean Claude Pradier and the Brazilian Rabbi Isaac Rabier sharing the same artist Jewish religious line. Interviews were also conducted with Chagall in several stages of his life, acquired in video and audio. It was concluded that in the analysed work, symbolic elements related to Judaism and Christianity, are together as regards to the meanings that refer to human feelings with emphasis in universal love and their relationship with divine love. / Esta dissertação apresenta e analisa o símbolo do cordeiro na obra de Marc Chagall, Os noivos e os três músicos", datado em 1972.Nessa obra, esse símbolo está relacionado à idéia de sacrifício como parte do amor incondicional. A análise dessa pintura implicou no estudo detalhado da vida do artista, com ênfase na sua memória religiosa. Chagall nasceu na Rússia, filho de judeus viveu em uma aldeia tradicionalmente judaica, em 1887 e iniciou-se no mundo artístico no início do século XX, em 1910, quando mudou-se para Paris. O uso que faz dos símbolos permite compreender mais adequadamente sua produção artística, bem como sua trajetória pessoal. O objetivo principal deste estudo foi apontar as relações entre a obra de arte do artista e a influência que sofreu na cultura por meio da educação religiosa. Por isso mesmo, esta pesquisa tem um caráter interdisciplinar e se insere perfeitamente no programa de pós-graduação em Educação, Arte e História da Cultura da Universidade Presbiteriana Mackenzie. As principais referências bibliográficas remetem as teorias propostas por Jean Paul Ronecker, quando se refere ao simbolismo do animal na história da cultura e na arte com as contribuições de Carl Gustav Jung através do livro O homem e seus símbolos. Com base teórica sobre o simbolismo na cultura religiosa, envolvendo o judaísmo e o cristianismo, foram também consultados Anatol Rosenfeld e o filósofo brasileiro Mário Ferreira dos Santos. Do ponto de vista metodológico, vários caminhos foram percorridos: visitas a museus com exposições das obras de arte de Chagall, no Brasil e na França, bem como entrevistas com um artista francês Jean Claude Pradier e o rabino brasileiro Isaac Rabier que compartilha da mesma linha religiosa judaica do artista. Foram também utilizadas entrevistas realizadas com Chagall em diversas fases de sua vida, adquiridas em vídeo e em áudio.Concluiu-se que na obra analisada, elementos simbólicos relacionados ao judaísmo e ao cristianismo, estão juntos no que se refere aos significados que remetem aos sentimentos humanos, com ênfase no amor universal e suas relações com o amor divino.
257

Assessing demand for organic lamb using choice modelling

Rutledge, M. P. January 2009 (has links)
The worldwide market for organic foods is growing fast, but New Zealand meat producers have been slow to respond. Specifically, New Zealand producers have little or no organic lamb products for export or domestic sale. Part of the reason for this hesitancy to meet demand with supply is that the nature of the demand and consumer willingness to pay for the product is not well understood. The purpose of this study is to investigate New Zealand organic food consumers’ attitudes towards organic food and production methods and to evaluate consumer willingness to pay for an organic lamb product. Data for this study was collected using computer aided personal interviewing (CAPI) in supermarkets and speciality stores in Christchurch and Wellington. The study questioned consumers about their consumption habits, attitudes towards organic food and production methods and presented choice modelling scenarios to test willingness to pay for different attributes of lamb. Factor analysis is used to group the 12 attitudinal questions into three factors which were then placed into a two step cluster analysis to create consumer segments. Choice modelling was then used to measure consumer preferences for the tested attributes of lamb. From the factor and cluster analysis three distinct consumer segments were found and labelled as Committed Organic Seekers, Convenience Organic Consumers and Incidental Organic Consumers. These labels reflect each group’s organic consumption habits and attitudes towards organic food. The choice modelling results show that there is a willingness to pay for organic lamb. The three identified consumer groups state they would pay a premium of 61%, 44% and 26% respectively for organic lamb over standard pasture raised lamb. This paper gives an insight into consumer attitudes and preferences towards a product that could provide a way for New Zealand farmers to increase their returns. It contributes to the body of knowledge about the likely consumer profiles of regular consumers of organic food. There are only a few other studies that have attempted to measure consumer attitudes and willingness to pay for organic meat, however, the author is not aware of any published example of a study that has specifically investigated demand for organic lamb anywhere in the world. The study provides information about stated willingness to pay for five different attributes of lamb; this information should be of value in assisting the industry by showing which product offerings are likely to generate the highest sale price.
258

The effect of pre-rigor infusion of lamb with kiwifruit juice on meat quality

Han, Jin January 2008 (has links)
Tenderness, juiciness, colour and flavour are the most important meat quality attributes affecting the consumer acceptance. Maintaining the consistency of meat products by avoiding variable quality has become a major concern and great challenge to the meat industry. This in turn will also benefit meat end-users in the marketplace by having more tender meat. The present study was designed to evaluate the overall effects of pre-rigor infusion with kiwifruit juice, which contains the plant protease, actinidin, on lamb quality. A total of 18 lambs (12 months old) were divided into three treatment groups (6 lambs per each treatment). After exsanguination, lamb carcasses were infused (10% body weight) with fresh kiwifruit juice (Ac), water (W) and compared with a noninfusion treatment which acted as a control (C). Samples from different muscle/cuts (longissimus dorsi (LD) vs leg chops) at different post-mortem times (1 day post-mortem vs. 3 wks vacuum packaged storage at 2°C) and display time (0 to 6 days after the post-mortem storage) were analysed to monitor the changes on meat physical properties (e.g., tenderness, temperature, drip and cooking loss, colour), biochemical changes (pH, proteins and lipids) and volatile flavour compounds after the infusion treatments. The most tender meat (lowest shear force values) (P < 0.001) detected in the Ac carcasses post-mortem compared with C and W carcasses demonstrated that kiwifruit juice was a very powerful meat tenderizer, and could contribute to the meat tenderization process efficiently and effectively. Compared with C and W carcasses, the enhanced proteolytic activity (P = 0.002) resulting from the actinidin in kiwifruit juice in Ac carcasses caused degradation of the myofibrillar proteins and the appearance of new peptides during postmortem ageing. A slight positive effect in a*-value (redness) and decreased lipid oxidation, found in leg chops, was thought to be caused by the natural antioxidants in kiwifruit juice. Kiwifruit juice infused into the meat did not alter (P > 0.05) the volatile flavour compound profile indicating that the meat from Ac treated carcasses maintained its natural lamb flavour. No treatment differences were found for the temperature decline (P > 0.05) between the infused treatments and C. The higher rate of pH decline (P < 0.05) found in W carcasses might have contributed to the higher drip and cooking loss. The unbound water in meat might contribute to the higher L*-values (lightness) found in W carcasses. In summary, the proteolytic tenderizing infusion treatment using kiwifruit juice is a feasible approach for the commercial meat industry to increase profits, and also could satisfy the eating quality standards required by the consumers. In addition, tenderizing meat by using kiwifruit juice could also provide the kiwifruit processors an additional option for use of their product to gain a more profitable return.
259

Association de la shearographie et des ondes de Lamb pour la détection rapide et quantitative des délaminages

Taillade, Frédéric 17 November 2000 (has links) (PDF)
Les travaux de recherche présentés dans cette thèse contribuent au développement du contrôle non destructif (CND) des plaques minces constituées de matériaux composites stratifiés. La méthode développée est une technique hybride associant les ondes ultrasonores<br />guidées (ondes de Lamb) comme moyen de sollicitation et un interféromètre de speckle particulier (la caméra de shearographie) comme outil de mesure. L'objectif de<br />ces travaux est d'évaluer les performances de cette technique pour détecter, localiser et quantifier des délaminages dans des plaques de carbone époxy.<br />Une étude de l'interféromètre de shearographie a permis d'expliciter sa sensibilité vis à vis des composantes du vecteur déplacement. Un effort particulier a été mené pour caractériser métrologiquement ce dispositif de mesure de phase optique. Un bilan d'incertitude montre notamment que la phase peut être mesurée avec une incertitude type de 2PI/50.<br />Nous avons alors mis en oeuvre les ondes de Lamb afin d'élaborer la méthode de CND proprement dite. Deux modes de visualisations des ondes de Lamb (mode passe bande et réjection de bande) adaptés à la longueur d'onde de celles-ci ont été mis au point. Plusieurs<br />résultats de visualisations des ondes de Lamb et de l'interaction avec les délaminages confirment les possibilités de cette méthode. Une interprétation des images shearographiques de l'interaction ondes/délaminages reposant sur un modèle mécanique de diffraction d'une onde par un trou débouchant cylindrique permet de rendre cette méthode quantitative.<br />Les résultats expérimentaux sont alors comparés à des cartographies obtenues par thermographie infrarouge stimulée du délaminage.
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Mesure et prévision de l'évolution des endommagements dans les composites stratifiés

Bois, Christophe 17 December 2003 (has links) (PDF)
Depuis quelques années, de nombreuses études portent sur la «Surveillance de Santé des Structures». La plupart de ces études concernent la mesure des endommagements. Si ces mesures permettent de connaître l'état de la structure, elles ne permettent pas de savoir si les endommagements mesurés sont acceptables ou s'ils nécessitent une intervention. Il est donc nécessaire de pouvoir prédire l'évolution des endommagements pour réaliser un véritable système de surveillance. D'autre part, la modélisation seule n'est également pas suffisante. En effet, dans le cas des chargements de service, statique ou de fatigue, les incertitudes sur les conditions aux limites et les imperfections du modèle ne sont pas négligeables. Il est donc nécessaire de recaler les modèles par des mesures. Dans le cadre de ce travail, nous proposons de réaliser un système de surveillance complet pour les stratifiés constitués de plis tissés associant la mesure de l'endommagement diffus (micro-décohésions entre fibres et matrice) et la prévision de son évolution. Nous proposons également de détecter les zones délaminées et les fissures complètes de stratifié. La mesure de l'impédance d'un transducteur piézoélectrique est utilisée pour caractériser un délaminage. Pour cela un modèle électromécanique, basé sur la théorie des stratifiés, est développé pour des structures poutres présentant un délaminage. Ce modèle est validé par des résultats expérimentaux et il est ensuite utilisé pour caractériser le délaminage par calcul inverse. La mesure d'impédance est également utilisée pour déterminer un niveau d'endommagement diffus. En particulier, l'influence de ce type d'endommagement sur les fréquences de résonance et l'amortissement est étudiée. Une méthode ultrasonore basée sur la propagation d'ondes de Lamb est employée pour détecter les macro-endommagements (fissure complète de stratifié et délaminage). Une confrontation entre des simulations éléments finis et des résultats expérimentaux nous ont permis de mieux comprendre les phénomènes d'interaction entre les ondes et le défaut.

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