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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

Cultivo da microalga Chlorella spp. em pequena escala visando ao aumento da produção de biomassa e óleos para biodiesel / Optimization of cultivation of microalgae Chlorella spp. in photobioreactors types airlift and bags: biomass as an alternative source of biodiesel

Acioli, Tácyo Santos 30 September 2014 (has links)
Os combustíveis derivados do petróleo são notadamente reconhecidos como fontes insustentáveis de energia, visto que há um empobrecimento das suas fontes, e ainda pela contribuição nas mudanças climáticas globais. Nesse cenário, os biocombustíveis aparecem como alternativa renovável frente às não-renováveis. No Brasil, a inserção de fontes renováveis na matriz energética tem crescido ao longo das últimas décadas, onde o biodiesel tem desempenhado um papel de destaque. A linha de frente da produção está centrada nos vegetais superiores e resíduos contendo óleos vegetais e animais, entretanto, estas não são as únicas fontes de matéria-prima para a fabricação do biodiesel. Microalgas oleaginosas são uma alternativa potencial que resolve, em parte, alguns dos problemas associados ao biodiesel oriundo de óleos vegetais e animais. As microalgas podem acumular significativas quantidades de lipídeos (até mais que 50% do seu peso seco) e gerar grande quantidade de biomassa, porém, não se encontram disponíveis na natureza em concentrações que suportem exploração comercial, salvo exceções. Portanto, para serem produzidas em larga escala, podem ser utilizados sistemas controlados de cultivo. Dentro desse contexto, a pesquisa foi dividida em 3 etapas que visaram atingir os seguintes objetivos: (1) Através de técnicas de axenização, purificar duas cepas de Chlorella spp. para que os resultados obtidos pudessem ser atribuídos exclusivamente à alga; (2) Estudar o comportamento de duas cepas em dois meios de cultura distintos (WC e TAP) utilizando glicose como fonte orgânica de carbono e investigar fatores físicos e químicos para otimizar a produtividade de biomassa e lipídeos em relação à esses fatores. (3) Com os fatores escolhidos e otimizados, avaliar de forma simplificada o cultivo em média escala (fotobiorreatores de 10 L). A cepa de Chlorella DAM5% 04 apresentou os melhores resultados quanto às velocidades de crescimento, e por isso foi escolhida. Para monitorar o crescimento, foram utilizadas as absorbâncias calibradas previamente por sólidos suspensos. O modelo de Gompertz foi utilizado para a modelagem do crescimento e gerou curvas e parâmetros de crescimento (amplitude, velocidades máximas específicas de crescimento e tempo de geração). A adição de glicose aos meios de cultura aumentou 4 vezes as velocidades de crescimento quando comparado ao meio WC padrão (de 0,30 UFC mL-1 dia-1 para 1,23 UFC mL-1 dia-1. A relevância da glicose no meio TAP foi em relação à biomassa produzida, que dobrou seu valor em relação ao WC e TAP padrão (de 500 mg.L-1 para 1090 mg.L-1). Na investigação dos fatores químicos, a retirada de enxofre do meio foi responsável por aumentar em mais de 7 vezes o valor da fluorescência de lipídeos neutros (de 1 u.a para 7,8 u.a.), sendo o mais eficiente. Na combinação dos fatores envolvidos, a produção de biomassa chegou ao 2000 mg.L-1, ao passo que a fluorescência de lipídeos chegou às 14 u.a. O ponto ótimo para produção de biomassa e fluorescência de lipídeos neutros encontrado pelo modelo de otimização utilizado foi de 98 mg L-1 de nitrogênio, 51 mg L-1 de fósforo, 0 mg L-1 de enxofre e 200 μmol fótons m-2 s-1 para o meio de cultura. Esses valores foram utilizados na fase posterior, o cultivo nos fotobiorreatores. Foi constatado que o airlift é mais suscetível à contaminação da cultura (comprovado microscopicamente) do que as bags, o que interferiu nos resultados. As maiores velocidades específicas de crescimento foram obtidas no reator airlift (5,77 d-1) para o cultivo com ar enriquecido em CO2 (2%), sendo de 4 a 5 vezes maiores do que as obtidas em pequena escala (tubos de ensaio). Em relação à biomassa, o cultivo no airlift apresentou 2550 mg L-1. A fluorescência de lipídeos neutros não ultrapassou 1 u.a, em todos os experimentos realizados nos fotobiorreatores, muito aquém dos valores encontrados nos tubos. / Oil-based fuels are notably recognized as unsustainable sources of energy, as their sources are impoverished, as well as their contribution to global climate change. In this scenario, biofuels appear as a renewable alternative to non-renewable ones. In Brazil, the insertion of renewable sources in the energy matrix has grown over the last decades, where biodiesel has played a prominent role. The production front line is centered on top vegetables and residues containing vegetable and animal oils, however, these are not the only sources of raw material for the production of biodiesel. Oil microalgae are a potential alternative that solves, in part, some of the problems associated with biodiesel from vegetable and animal oils. Microalgae can accumulate significant amounts of lipids (up to more than 50% of their dry weight) and generate large amounts of biomass, but are not available in nature at concentrations that support commercial exploitation, except for exceptions. Therefore, to be produced on a large scale, controlled cropping systems can be used. Within this context, the research was divided into 3 stages that aimed to achieve the following objectives: (1) Through axenization techniques, to purify two strains of Chlorella spp. So that the results obtained could be attributed exclusively to the algae; (2) To study the behavior of two strains in two different culture media (WC and TAP) using glucose as an organic carbon source and to investigate physical and chemical factors to optimize biomass and lipid productivity in relation to these factors. (3) With the chosen and optimized factors, to evaluate in a simplified way the cultivation in medium scale (10B photoboreaders). The Chlorella strain DAM5% 04 presented the best results regarding growth rates, and it was therefore chosen. To monitor growth, the absorbances previously calibrated by suspended solids were used. The Gompertz model was used for growth modeling and generated growth curves and parameters (amplitude, maximum growth speeds and generation time). The addition of glucose to the culture media increased the growth rates 4 fold compared to standard WC media (0.30 CFU mL-1 day-1 to 1.23 CFU mL-1 day-1). In the investigation of the chemical factors, the removal of sulfur from the medium was carried out in the same way as the biomass produced, which doubled its value in relation to WC and standard TAP (from 500 mgL-1 to 1090 mg L-1). Which is responsible for increasing the fluorescence value of neutral lipids by more than 7 times (from 1 ua to 7.8 ua), being the most efficient. In the combination of the factors involved, biomass production reached 2000 mg.L-1, Whereas the lipid fluorescence reached 14 ua. The optimal point for the production of biomass and fluorescence of neutral lipids found by the optimization model was 98 mg L-1 of nitrogen, 51 mg L-1 of phosphorus, 0 mg L-1 of sulfur and 200 μmol photons m-2 s-1 for the culture medium. Phase, culture in photobioreactors. It has been found that the airlift is more susceptible to contamination of the crop (microscopically proven) than bags. The highest specific growth rates were obtained in the airlift reactor (5.77 d-1) for CO2-enriched air (2%) cultivation, 4 to 5 times higher than those obtained on a small scale (test tubes). In relation to biomass, the airlift culture presented 2550 mg L-1. Neutral lipid fluorescence did not exceed 1 u.a. in all experiments performed on photobioreactors, well below the values found in the tubes.
2

An assessment of strategies for the management of plastic bag wastes in Hong Kong /

Ng, Ting-leung, Gordon. January 1994 (has links)
Thesis (Ph. D.)--University of Hong Kong, 1995. / Includes bibliographical references (leaf 273-291).
3

Cultivo da microalga Chlorella spp. em pequena escala visando ao aumento da produção de biomassa e óleos para biodiesel / Optimization of cultivation of microalgae Chlorella spp. in photobioreactors types airlift and bags: biomass as an alternative source of biodiesel

Tácyo Santos Acioli 30 September 2014 (has links)
Os combustíveis derivados do petróleo são notadamente reconhecidos como fontes insustentáveis de energia, visto que há um empobrecimento das suas fontes, e ainda pela contribuição nas mudanças climáticas globais. Nesse cenário, os biocombustíveis aparecem como alternativa renovável frente às não-renováveis. No Brasil, a inserção de fontes renováveis na matriz energética tem crescido ao longo das últimas décadas, onde o biodiesel tem desempenhado um papel de destaque. A linha de frente da produção está centrada nos vegetais superiores e resíduos contendo óleos vegetais e animais, entretanto, estas não são as únicas fontes de matéria-prima para a fabricação do biodiesel. Microalgas oleaginosas são uma alternativa potencial que resolve, em parte, alguns dos problemas associados ao biodiesel oriundo de óleos vegetais e animais. As microalgas podem acumular significativas quantidades de lipídeos (até mais que 50% do seu peso seco) e gerar grande quantidade de biomassa, porém, não se encontram disponíveis na natureza em concentrações que suportem exploração comercial, salvo exceções. Portanto, para serem produzidas em larga escala, podem ser utilizados sistemas controlados de cultivo. Dentro desse contexto, a pesquisa foi dividida em 3 etapas que visaram atingir os seguintes objetivos: (1) Através de técnicas de axenização, purificar duas cepas de Chlorella spp. para que os resultados obtidos pudessem ser atribuídos exclusivamente à alga; (2) Estudar o comportamento de duas cepas em dois meios de cultura distintos (WC e TAP) utilizando glicose como fonte orgânica de carbono e investigar fatores físicos e químicos para otimizar a produtividade de biomassa e lipídeos em relação à esses fatores. (3) Com os fatores escolhidos e otimizados, avaliar de forma simplificada o cultivo em média escala (fotobiorreatores de 10 L). A cepa de Chlorella DAM5% 04 apresentou os melhores resultados quanto às velocidades de crescimento, e por isso foi escolhida. Para monitorar o crescimento, foram utilizadas as absorbâncias calibradas previamente por sólidos suspensos. O modelo de Gompertz foi utilizado para a modelagem do crescimento e gerou curvas e parâmetros de crescimento (amplitude, velocidades máximas específicas de crescimento e tempo de geração). A adição de glicose aos meios de cultura aumentou 4 vezes as velocidades de crescimento quando comparado ao meio WC padrão (de 0,30 UFC mL-1 dia-1 para 1,23 UFC mL-1 dia-1. A relevância da glicose no meio TAP foi em relação à biomassa produzida, que dobrou seu valor em relação ao WC e TAP padrão (de 500 mg.L-1 para 1090 mg.L-1). Na investigação dos fatores químicos, a retirada de enxofre do meio foi responsável por aumentar em mais de 7 vezes o valor da fluorescência de lipídeos neutros (de 1 u.a para 7,8 u.a.), sendo o mais eficiente. Na combinação dos fatores envolvidos, a produção de biomassa chegou ao 2000 mg.L-1, ao passo que a fluorescência de lipídeos chegou às 14 u.a. O ponto ótimo para produção de biomassa e fluorescência de lipídeos neutros encontrado pelo modelo de otimização utilizado foi de 98 mg L-1 de nitrogênio, 51 mg L-1 de fósforo, 0 mg L-1 de enxofre e 200 μmol fótons m-2 s-1 para o meio de cultura. Esses valores foram utilizados na fase posterior, o cultivo nos fotobiorreatores. Foi constatado que o airlift é mais suscetível à contaminação da cultura (comprovado microscopicamente) do que as bags, o que interferiu nos resultados. As maiores velocidades específicas de crescimento foram obtidas no reator airlift (5,77 d-1) para o cultivo com ar enriquecido em CO2 (2%), sendo de 4 a 5 vezes maiores do que as obtidas em pequena escala (tubos de ensaio). Em relação à biomassa, o cultivo no airlift apresentou 2550 mg L-1. A fluorescência de lipídeos neutros não ultrapassou 1 u.a, em todos os experimentos realizados nos fotobiorreatores, muito aquém dos valores encontrados nos tubos. / Oil-based fuels are notably recognized as unsustainable sources of energy, as their sources are impoverished, as well as their contribution to global climate change. In this scenario, biofuels appear as a renewable alternative to non-renewable ones. In Brazil, the insertion of renewable sources in the energy matrix has grown over the last decades, where biodiesel has played a prominent role. The production front line is centered on top vegetables and residues containing vegetable and animal oils, however, these are not the only sources of raw material for the production of biodiesel. Oil microalgae are a potential alternative that solves, in part, some of the problems associated with biodiesel from vegetable and animal oils. Microalgae can accumulate significant amounts of lipids (up to more than 50% of their dry weight) and generate large amounts of biomass, but are not available in nature at concentrations that support commercial exploitation, except for exceptions. Therefore, to be produced on a large scale, controlled cropping systems can be used. Within this context, the research was divided into 3 stages that aimed to achieve the following objectives: (1) Through axenization techniques, to purify two strains of Chlorella spp. So that the results obtained could be attributed exclusively to the algae; (2) To study the behavior of two strains in two different culture media (WC and TAP) using glucose as an organic carbon source and to investigate physical and chemical factors to optimize biomass and lipid productivity in relation to these factors. (3) With the chosen and optimized factors, to evaluate in a simplified way the cultivation in medium scale (10B photoboreaders). The Chlorella strain DAM5% 04 presented the best results regarding growth rates, and it was therefore chosen. To monitor growth, the absorbances previously calibrated by suspended solids were used. The Gompertz model was used for growth modeling and generated growth curves and parameters (amplitude, maximum growth speeds and generation time). The addition of glucose to the culture media increased the growth rates 4 fold compared to standard WC media (0.30 CFU mL-1 day-1 to 1.23 CFU mL-1 day-1). In the investigation of the chemical factors, the removal of sulfur from the medium was carried out in the same way as the biomass produced, which doubled its value in relation to WC and standard TAP (from 500 mgL-1 to 1090 mg L-1). Which is responsible for increasing the fluorescence value of neutral lipids by more than 7 times (from 1 ua to 7.8 ua), being the most efficient. In the combination of the factors involved, biomass production reached 2000 mg.L-1, Whereas the lipid fluorescence reached 14 ua. The optimal point for the production of biomass and fluorescence of neutral lipids found by the optimization model was 98 mg L-1 of nitrogen, 51 mg L-1 of phosphorus, 0 mg L-1 of sulfur and 200 μmol photons m-2 s-1 for the culture medium. Phase, culture in photobioreactors. It has been found that the airlift is more susceptible to contamination of the crop (microscopically proven) than bags. The highest specific growth rates were obtained in the airlift reactor (5.77 d-1) for CO2-enriched air (2%) cultivation, 4 to 5 times higher than those obtained on a small scale (test tubes). In relation to biomass, the airlift culture presented 2550 mg L-1. Neutral lipid fluorescence did not exceed 1 u.a. in all experiments performed on photobioreactors, well below the values found in the tubes.
4

Beyond the disposable plastic grocery bag : the opportunity of bagless retail as seen through the lenses of morality, economics, and the environment

Tucker, Norel G. 30 November 2010 (has links)
This paper has attempted to accurately assess the impact of the disposable plastic grocery bag on the planet. Based on the research findings, it has been concluded that disposable plastic grocery bags are not a necessity, are not justifiable on many reasonable grounds, are costly, and are a toxic detriment to our health and our environment. The distribution of an educational executive briefing package attempted to influence retailers to avail of the opportunity (outlining potential profit, corporate image, and environmental benefits) of going bagless at the checkout, and to cease the use of disposable plastic bags in favour of the non-woven, polypropylene green bag. A shift to this reusable green bag appears to represent an important and effective interim measure towards more noble and sustainable living. Throughout this paper, the disposable plastic grocery bag will be considered through the lenses of morality, economics and the environment.
5

The Power of the Gift Bag : En studie om användandet av gift bags som marknadsföringskanal

Eder, Sarali, Sundblom, Silje January 2014 (has links)
In a time of fierce global competition, where an immense amount of commercial messages reaches consumers around the clock and in every conceivable context, companies constantly seek to find new ways to reach out with their product. One way to do so, that has increased in popularity in recent years, is the use of gift bags. A gift bag may contain samples, miniature products and even products in full size, as a rule from several different brands, which the recipient receives free of charge. The gift bag is typically distributed at some form of event, such as store openings, fashion shows, theme parties and the like, and the receiver of the gift bag can then evaluate the content without any obligation to purchase. The ambition of the companies that choose to participate with their products in a gift bag is, of course, that the recipient will find their products satisfactory, and ideally, that he or she will continue to consume the brand in the future. There are numerous scientific research contributions related to the use of free samples, but very few that concern the gift bag, where a collection of samples from different sources and brands appear. The ambition of this study is to investigate how the conditions change when a free sample is exposed to competition from samples from other companies. The study has a qualitative approach, and consists of interviews with companies that use, or have used, gift bags as a marketing channel, along with an interview with a focus group consisting of people with experience of participating in various events where gift bags occur. The study concludes that marketing through the use of gift bags can have several positive effects for the participating brands. These are, for example, increased brand awareness and an increase in sales. However, it is of importance to evaluate the competing brands participating in the gift bag, as well as the context in which it will be distributed. The study shows that the size of the sample is of importance, since the receiver tends to notice more voluminous samples over smaller ones. Also, the presence of more established brands can have a positive effect on less well-known brands, as their credit will enhance the other participating products. It is important to note that this is only true for samples that are not of the same product category. If this is the case, they will instead be in direct competition with each other.
6

The Nitrification of Ammonium Sulfate in Polyethylene Bags in the Field and Laboratory

Smith, Carlos Dean 01 May 1963 (has links)
There are many advantages and some disadvantages associated with the fall application of nitrogen fertilizers. The advantages of applying fertilizer at this time appear very convincing. It is easier to get onto the land in the fall. During the fall, famers usually have more time to apply fertilizer than they do in the spring. In the fall the fertilizer companies offer better service. This is because the fall application of fertilizer lengthens out their season, thus making it possible for them to handle more fertilizer.
7

Miljömedvetenhet och beteende vid konsumtionen av bärkassar i livsmedelsbutiker : En enkätstudie / Environmental awareness and behavior in the consumption of grocery bags in food stores : A survey

Bouraleh, Maryan, Forsgren, Elsa January 2018 (has links)
Denna studie undersöker konsumenternas beteende vid köp av bärkassar i livsmedelsbutiker. Konsumtionen av bärkassar är ett problem på flera sätt, denna rapport kommer undersöka konsumenternas kunskap om resurs och energiåtgång vid tillverkning, miljömedvetet beteende och konsumenternas förslag till beteendeförändring vid konsumtion av bärkassar. Syftet är att undersöka om kunskap får konsumenten att agera på ett visst sätt. För att kunna utföra arbetet har en enkätundersökning utförts, både i en vald ICA butik och på Facebook. Enkäten innehöll frågor om konsumtionen, som till exempel vad konsumenterna brukar köpa för bärkasse och hur ofta. Även hur konsumenten tagit sig till butiken är av intresse likaväl konsumentens tidigare kunskaper om resursåtgång vid tillverkning kommer att frågas efter. Sist kommer konsumentens inställning till ett infört förbud efterfrågas och vad som skulle kunna få personen att minska sin egen konsumtion. Studien har kommit fram till att det inte finns några kunskapsskillnader mellan de som köper och de som inte köper bärkassar. Det finns alltså ett value-action gap, konsumenten är medveten om att konsumtionen inte är hållbar men agerar inte utefter sin kunskap. Det mest effektiva sättet att minska konsumtionen anses därmed inte vara bättre kunskap om miljöpåverkan. Istället föredras ett förbud mot plastpåsar baserade på olja. Följaktligen borde butiker endast erbjuda miljökassar och de svenska papperspåsarna. Relativt få av de som deltagit i enkäten är mot ett förbud av engångsbärkassar och eftersom även konsumtionen av miljökassar och svenska papperspåsar har en negativ miljöpåverkan är också minskad konsumtion av alla dessa att föredra. Detta kan åstadkommas med ett ökat pris. / This study examines consumers’ behavior in the purchase of grocery bags in food stores. Consumption of all types of bags is a problem in several ways, and this report will examine consumers’ knowledge about resource and energy use in manufacturing, pro-environmental behavior and consumers’ suggestions to behavioral change while purchasing grocery bags. The purpose is to investigate whether knowledge causes the consumer to act in a certain way. To achieve the purpose, a survey was conducted, both in a selected ICA store and on Facebook. The survey contained questions about consumption such as, what bag consumers usually buy and how often. Even how the consumer went to the store is of interest as well as the costumers’ knowledge previous to the study regarding resource utilization in manufacturing. Lastly, the consumers’ attitude towards a potential ban was asked for, as well as what could make the person reduce his or her own consumption. The study found that there is no difference in knowledge between those who buy bags and those who do not. This leads to the conclusion that there is a value-action gap, one is aware that the consumption is not sustainable, but one does not act according to his or her knowledge. Thus, the most effective way of reducing consumption is not considered to be a better knowledge of environmental impact. Instead, a ban on plastic bags based on oil is preferred. Hence, environmental bags and Swedish paper bags would be more promising options. Relatively few of those who participated in the survey are against a ban on disposable bags. Because even the consumption of environmental bags and Swedish paper bags has a negative impact on the environment, a reduction of consumption of all bags is therefore preferable. This can be achieved with an increase in price.
8

Evaluating Risks and Mitigation Measures for Foodborne Pathogens on Harvest Bags

Ayuk Etaka, Cyril Nsom 07 June 2024 (has links)
Tree fruit growers need information on pathogen dynamics following harvest bags contamination to determine effective sanitation interventions for decontaminating these surfaces. Therefore, the objectives of this research were (i) to determine the survival of generic E. coli, Salmonella, and L. monocytogenes on different harvest bag materials (ii) to quantify the transfer of generic E. coli, Salmonella, and L. monocytogenes from different harvest bag materials to fresh unwaxed apples and (iii) to determine the efficacy of different sanitizers for decontaminating different harvest bag materials. For Obj. 1, harvest bag materials were inoculated with rifampicin-resistant (80ppm; R) E. coli (TVS353) or Salmonella strain cocktail or L. monocytogenes strain cocktail. All surfaces were air-dried and held at 22 °C and either 30 or 80% relative humidity for 90 d (E. coli), or at 22 °C and 55% relative humidity (RH) for 21 d (L. monocytogenes and Salmonella). For Obj. 2, harvest bag materials were inoculated with E. coli (TVS353) or Salmonella strain cocktail or L. monocytogenes strain cocktail and air dried as previously mentioned. For E. coli trials, bacterial transfer to unwaxed 'Red Delicious' apples was assessed for 2 inoculum dry times (1 or 4 h), 2 contact times (5 or 25 minutes), and 2 pressure scenarios (0.0 or 0.1kg/cm2). For Salmonella or L. monocytogenes trials, transfer was assessed for 1 inoculum dry time (1 h), and 1 contact time (5 minutes). For Obj. 3, coupons were inoculated with L. monocytogenes or Salmonella cocktails and were air-dried. Following inoculation, coupons were exposed to different sanitizer treatments: chlorine, peroxyacetic acid (PAA), isopropyl alcohol with quaternary ammonium compounds (IPAQuats), steam, and water. Regression models were fitted, and Tukey's post hoc test was performed at P<0.05. E. coli exhibited survival for extended durations at 30 % than at 80% RH. In addition, E. coli survived at higher concentrations on canvas surfaces than on cordura and nylon surfaces. Generally, E. coli survived for more than 21 d across all surfaces and exhibited a triphasic die-off pattern. Similarly, L. monocytogenes and Salmonella exhibited die-off in phases with an initial rapid die-off followed by more gradual die-off rates up to 21 d. Canvas materials also promoted better L. monocytogenes and Salmonella survival than cordura surfaces. Contact time did not significantly impact the transfer of E. coli from harvest bag surfaces to apples (P=0.55). However, pressure, inoculum dry time and material type significantly impacted the transfer of E. coli to 'Red Delicious' apples (P≤0.03). The transfer rates of Salmonella did not differ between canvas and cordura surfaces (P=0.46). However, cordura transferred L. monocytogenes at significantly higher rates than canvas surfaces (P<0.001). Of the sanitizer treatments that were used on L. monocytogenes or Salmonella inoculated surfaces, IPAQuats was the most effective achieving over 4.5 log CFU/coupon reduction on both canvas and cordura surfaces. Our studies demonstrated that bacteria could survive for over 21 d under different conditions and could transfer from contaminated harvest bag surfaces to apples underlining the importance of cleaning and sanitizing harvest bags with sanitizers like IPAQuats. / Doctor of Philosophy / Tree fruit growers need information on pathogen behavior on harvest bag surfaces to determine effective sanitation interventions for decontaminating these surfaces. Therefore, the objectives of this research were (i) to determine the survival of generic E.coli, Salmonella, and L. monocytogenes on different harvest bag materials (ii) to quantify the transfer of generic E. coli, Salmonella, and L. monocytogenes from different harvest bag materials to fresh unwaxed apples and (iii) to determine the efficacy of different sanitizers for decontaminating different harvest bag materials. For Obj. 1, harvest bag materials were inoculated with E. coli (TVS353) or Salmonella strain cocktail or L. monocytogenes strain cocktail. All surfaces were air-dried and held for 90 d (E. coli), or 21 d (L. monocytogenes and Salmonella). For Obj. 2, harvest bag materials were inoculated with E. coli (TVS353) or Salmonella strain cocktail or L. monocytogenes strain cocktail and air dried as previously mentioned. For E. coli trials, bacterial transfer to unwaxed 'Red Delicious' apples was assessed for 2 drying conditions (wet or visibly dry), 2 contact times (5 and 25 minutes), and 2 pressure scenarios (0.0 and 0.1kg/cm2). For Salmonella or L. monocytogenes trials, transfer was assessed for wet surfaces only and apples sat on surfaces for 5 minutes. For Obj. 3, harvest bags were inoculated with L. monocytogenes or Salmonella cocktails and exposed to different sanitizer treatments including chlorine, peroxyacetic acid (PAA), isopropyl alcohol with quaternary ammonium compounds (IPAQuats), steam, and water. Regression models were fitted, and Tukey's post hoc test was performed at P<0.05. Canvas surfaces promoted better E. coli survival compared to cordura and nylon surfaces. Similarly, canvas materials also supported better L. monocytogenes and Salmonella survival compared to cordura surfaces. Contact time did not significantly impact the transfer of E. coli from harvest bag surfaces to apples (P=0.55). However, pressure, inoculum dry time and material type significantly impacted the transfer of E. coli to 'Red Delicious' apples (P≤0.03). The transfer rates of Salmonella did not differ between canvas and cordura surfaces (P=0.46). However, cordura transferred L. monocytogenes at significantly higher rates than canvas surfaces (P<0.001). Of the sanitizer treatments that were used on L. monocytogenes or Salmonella inoculated surfaces, IPAQuats was the most effective achieving over 4.5 log CFU/coupon reduction on both canvas and cordura surfaces. Our studies demonstrated that bacteria could survive for over 21 d under different conditions and could transfer from contaminated harvest bag surfaces to apples underlining the importance of cleaning and sanitizing harvest bags with sanitizers like IPAQuats.
9

Use of self-inflating bags for neonatal resuscitation

Oddie, S.J., Wylie, J., Scally, Andy J. January 2005 (has links)
No / Lung inflation is the most important, and most difficult step in newborn resuscitation. A wide variety of devices are used to achieve lung inflation, but there are relatively few data to guide clinicians in their choice of device. We tested the ability of instructors and trained candidates on a newborn life support course to deliver initial inflation breaths to a test lung, using a pressure limited blow-off valve, a 240-ml self-inflating bag and a 500-ml self-inflating bag in sequence. Use of a 240-ml self-inflating bag was associated with shorter initial inflations of 1.8 s mean (95% CI 1.60-1.99 s), compared with 2.42 s (2.24-2.61 s), 2.40 s (2.08-2.71 s) for 500-ml self-inflating bags and 'Tom Thumb' T piece, respectively. Delivery of breaths within a target pressure range of 30 � 5 cm H2O was significantly better using a T piece than either self-inflating bag (proportion within target range 0.05 (95% CI 0-0.11), 0.17 (95% CI 0.12-0.23), 0.89 (95% CI 0.83-0.94) for 240-ml and 500-ml self-inflating bags and 'Tom Thumb' T piece, respectively. Excessive pressure delivery with both sizes of self-inflating bag was frequent. These data do not support use of 240-ml or 500-ml self-inflating bags for resuscitation of newborn term infants. A variable pressure T piece blow-off system may be the easiest device to use for newborn resuscitation and the most reliable at delivering desired pressures for set times.
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En förstudie för återvinning av plastpåsar i Borås och dess miljöpåverkan / A feasibility study of the recycling of consumer plastic bags in Borås and its environmental impact

Jogner, Carolina, Ibrahim, Zin January 2016 (has links)
Under den senaste tiden har man tagit upp plastbärkassars negativa miljöpåverkan, i EU men även lokalt i Borås. EU anser att plastpåsar är skadliga för miljön och har tagit fram direktiv som gör att alla medlemsstater måste vidta åtgärder för att begränsa förbrukningen av plastpåsar. För att man ska kunna fatta rätt beslut krävs det att man ökar kunskapen om vilka åtgärder som krävs och vilka åtgärder som är mest effektiva för att minska förbrukningen.I detta examensarbete är syftet att jämföra plastpåsars miljöpåverkan mot bärkassar i olika material samt att se över hur plastpåsar hanteras idag, presentera en metod för att utföra en insamling av plastpåsar för återvinning i Borås och utreda om det är miljömässigt lönsamt. Resultaten visar att bestämandet av en bärkasses miljöpåverkan är en mycket komplex fråga då väldigt många faktorer måste vägas in. Vi ser även att införandet av ett separat återvinningssystem för plastpåsar inte är det ultimata då det skulle försvåra logistiken samt kräva komprimering av plastpåsarna för att minska deras volym. Det befintliga återvinningssystemet för plast där man blandar hårdplast och mjukplast är mera lämpligt att använda då det ger en tätare blandning. / The negative environmental impact of plastic bags has recently been brought up in the EU but also locally in Borås. The EU considers that plastic bags are hurtful for the environment and has developed directive to reduce the consumption of plastic bags which all member states must follow. In order to be able to make the correct decisions it is necessary to have the accurate information of what measures are necessary to reduce consumption. In this thesis, the aim is to compare the environmental impact of plastic bags compared to bags in various materials and to review how plastic bags are managed today, present a method for how to collect plastic bags for recycling in Borås and investigate whether it is environmentally viable. The results show that the determination of the environmental impact of different bags is a very complex issue because so many factors must be considered. We also see that the introduction of a separate recycling system for plastic bags is not the ultimate method when it would complicate logistics and require compression, to reduce their volume. The existing recycling system for plastic which blends hard plastic and soft plastic, is more convenient to use as it provides a denser mixture.

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