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My work is a collection of narratives. Each one is the unfolding of the story of a person or thing. Several pieces are made up of objects that tell the story of their owners, giving clues to their lifestyles and experiences. I am interested in the story behind the things and people that I come across on a daily basis. For instance, what was housed in the drawers of the dresser I found in a thrift shop? Who drank from the milk bottle I now use as a vase? If I see a discarded toy on the street, I wonder what events led up to its abandonment. The way in which all of the represented objects and people are linked is left ambiguous, so that the viewer can create their own narrative. The more abstracted pieces are close-ups of objects. These pieces document the wearing away or fraying of something, telling many stories over several years, possibly portraying a wall that has been painted over many times, causing it to flake, or a shirt that has been worn to the point of disrepair.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

活性碳是一種擁有優異吸附能力的材料。與其他活性碳相比，活性碳纖維有以下優點。使首先, 它擁有大量微孔，比表面積大；其次，纖維結構有利於快速吸附；最後，它能編織成氈或者布，不但無阻氣流，而且便於使用後回收。但是，由於缺乏廉價的原材料，它的生產成本遠比其他活性碳高，不利於廣泛使用。所以，我們希望透通過使用廉價的棉花作為原材料，生產出優質的活性碳纖維。 / 在這項研究中，我們成功地用普通的棉花，通過氯化鋅活化，生產出活性碳纖維；我們研究了活化時的燒結溫度，浸潤時的氯化鋅濃度和活化後的後處理對活性碳纖維的影響，而且通過不同表徵方法來分析樣品。結果表明，它們不但保留棉花的纖維結構，而且擁有少量碳氧表面官能基。它的孔結構以微孔為主，BET比表面積和孔體積分別高達~2050m²/g和1 cm³/g，比市場上的活性碳或其他研究的活性碳高。 / 我們測試了棉花活性碳纖維在吸附亞甲基藍的吸附速度和吸附等溫線，發現它有很高的吸附速度，只需大約一個小時，吸附已差不多到達平衡。因為它很高的BET比表面积，它吸附亞甲基藍的最高容量達到597 mg/g，比市場上的活性碳高。我們也研究了溶液的pH值對其吸附能力的影響，發現鹼性環境有利亞甲基藍的吸附，相反，酸性環境不利亞甲基藍的吸附。 / 我們也測試了棉花活性碳纖維對水蒸氣，乙醇蒸氣、甲醇蒸氣和丙酮蒸氣的吸附速度，吸附容量和解吸過程。它只需十分鐘便完成乙醇蒸氣、甲醇蒸氣和丙酮蒸氣的吸附。它在水蒸氣中的吸附也比市場上的矽膠快。所有吸附物只需低於200 °C即可完全解吸。蒸氣吸附的最高容量高達1 cm³/g，較其他研究為高。 / Activated carbon (AC) is an important functional material due to its outstanding adsorption ability. Activated carbon fiber (ACF) has many advantages over other types of AC: It mainly possesses micropores and has large surface area. Its fibrous structure assures fast intraparticle adsorption kinetics. Finally, it can be made into felt and fabric forms, which would not hinder gas flow and could be easily recollected after use. However, ACF is expensive due to the lack of low cost precursor so its application is restricted. This work aims to use low cost cotton fiber as an ACF precursor. / In this work, ACF was successfully synthesized by using raw cotton via ZnCl₂ activation. The effects of the sintering temperature during activation, the ZnCl₂ concentration during infiltration and the post-treatment after activation on our samples were studied. Our ACF products were characterized via various methods. It was found that our samples retained the fibrous structure of cotton. They contained trace of carbon-oxygen surface groups and were mainly composed of micropores. Their BET surface area (S[subscript Bsubscript Esubscript T]) and pore volume (V[subscript psubscript osubscript rsubscript e]) were up to~ 2050 m²/g and 1 cm³/g, respectively. / The adsorption kinetics and adsorption isotherm of our samples in the Methylene blue (MB) adsorption were studied. The adsorption was very fast and almost reached equilibrium after an hour. Because of their high S[subscript Bsubscript Esubscript T], the saturated MB capacity in our ACF was found to be 597 mg/g and higher than other commercial AC. The effect of solution pH value on MB adsorption capacity was studied. We found that the basic condition favored MB adsorption while acidic condition lowered the adsorption ability. / Adsorption kinetics, saturated adsorption volume (V[subscript asubscript dsubscript s]) and desorption process of moisture, ethanol vapor, methanol vapor and acetone vapor by our samples were also evaluated. The adsorption of methanol vapor, ethanol vapor and acetone vapor reached equilibrium within 10 minutes. Our sample also adsorbed moisture faster than commercial silica gel. Less than 200 °C was required for complete desorption of these adsorbed species. V[subscript asubscript dsubscript s] of our samples was up to 1 cm³/g and higher than other related works. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chiu, Ka Lok = 棉花活性碳纖維的製作, 定性分析及其應用 / 趙家樂. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Chiu, Ka Lok = Mian hua huo xing tan xian wei de zhi zuo, ding xing fen xi ji qi ying yong / Zhao Jiale. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgment --- p.iv / Table of contents --- p.v / List of figure captions --- p.viii / List of table captions --- p.xii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- What is activated carbon --- p.1 / Chapter 1.2 --- Development of activated carbon --- p.2 / Chapter 1.3 --- Morphology of activated carbon --- p.3 / Chapter 1.4 --- Surface groups on activated carbon --- p.7 / Chapter 1.5 --- Fabrication of activated carbon --- p.8 / Chapter 1.6 --- Applications --- p.9 / Chapter 1.7 --- Activated carbon fiber --- p.10 / Chapter 1.8 --- Raw materials --- p.11 / Chapter 1.8.1 --- Precursors of powdered activated carbon and granular activated carbon --- p.11 / Chapter 1.8.2 --- Precursors of activated carbon fiber --- p.12 / Chapter 1.8.3 --- Cotton as activated carbon fiber precursor --- p.12 / Chapter 1.9 --- Previous work and objectives of current work --- p.13 / References --- p.14 / Chapter Chapter 2 --- Methodology and background theory --- p.19 / Chapter 2.1 --- Samples preparation --- p.19 / Chapter 2.2 --- Characterization methods --- p.21 / Chapter 2.2.1 --- Study of processing --- p.21 / Chapter 2.2.1.1 --- Thermogravimetric analysis --- p.21 / Chapter 2.2.1.2 --- In-situ wide angle X-ray powder diffractometry --- p.22 / Chapter 2.2.2 --- Characterization of samples --- p.23 / Chapter 2.2.2.1 --- Scanning electron microscopy --- p.23 / Chapter 2.2.2.2 --- Transmission electron microscopy --- p.24 / Chapter 2.2.2.3 --- Ex-situ wide angle X-ray powder diffractometry --- p.25 / Chapter 2.2.2.4 --- Small angle X-ray scattering --- p.25 / Chapter 2.2.2.5 --- Raman scattering spectroscopy --- p.26 / Chapter 2.2.2.6 --- Fourier transform infrared spectroscopy --- p.27 / Chapter 2.2.2.7 --- N₂ adsorption surface analysis --- p.27 / Chapter 2.2.2.8 --- Zeta potential analysis --- p.29 / Chapter 2.3 --- Evaluation of Methlyene blue adsorption --- p.29 / Chapter 2.3.1 --- Pseudo second order adsorption model --- p.30 / Chapter 2.3.2 --- Langmuir isotherm --- p.31 / Chapter 2.4 --- Evaluation of vapor adsorption --- p.31 / Chapter 2.4.1 --- Vapor adsorption kinetics --- p.31 / Chapter 2.4.2 --- Saturated adsorption capacity --- p.33 / Chapter 2.4.3 --- Desorption --- p.34 / Chapter 2.5 --- Conclusions --- p.34 / References --- p.35 / Chapter Chapter 3 --- Results of characterization --- p.37 / Chapter 3.1 --- Study of the fabrication processes --- p.37 / Chapter 3.1.1 --- Thermogravimetric analysis --- p.37 / Chapter 3.1.2 --- In-situ wide angle X-ray powder diffractometry --- p.38 / Chapter 3.2 --- Characterization of samples --- p.39 / Chapter 3.2.1 --- Appearance --- p.39 / Chapter 3.2.2 --- Yield of the sample --- p.41 / Chapter 3.2.3 --- Scanning electron microscopy --- p.42 / Chapter 3.2.4 --- Transmission electron microscopy --- p.45 / Chapter 3.2.5 --- Ex-situ wide angle X-ray powder diffractometry --- p.46 / Chapter 3.2.6 --- Raman scattering spectroscopy --- p.48 / Chapter 3.2.7 --- Fourier transform infrared spectroscopy --- p.53 / Chapter 3.2.8 --- Nitrogen gas sorption surface analysis --- p.57 / Chapter 3.2.9 --- Small angle x-ray scattering analysis --- p.61 / Chapter 3.2.10 --- Zeta potential analysis --- p.65 / Chapter 3.3 --- Discussions --- p.66 / Chapter 3.3.1 --- Effects of ZnCl₂ on carbonization --- p.66 / Chapter 3.3.2 --- Pore formation --- p.68 / Chapter 3.3.3 --- Graphitic layers --- p.69 / Chapter 3.3.4 --- Effects of post treatment --- p.70 / Chapter 3.4 --- Conclusions --- p.71 / References --- p.72 / Chapter Chapter 4 --- Methylene blue adsorption --- p.74 / Chapter 4.1 --- Results --- p.74 / Chapter 4.1.1 --- Adsorption kinetics --- p.74 / Chapter 4.1.2 --- Adsorption capacity versus pH level --- p.76 / Chapter 4.1.3 --- Adsorption isotherm --- p.77 / Chapter 4.1.4 --- Adsorption capacity in different synthetic conditions --- p.78 / Chapter 4.2 --- Discussions --- p.80 / Chapter 4.2.1 --- Relationship between adsorption capacity and zeta potential --- p.80 / Chapter 4.2.2 --- Relationship between MB adsorption capacity and SBET --- p.81 / Chapter 4.2.3 --- Comparison with other related works --- p.83 / Chapter 4.3 --- Conclusions --- p.85 / References --- p.86 / Chapter Chapter 5 --- Vapor adsorption --- p.87 / Chapter 5.1 --- Results --- p.87 / Chapter 5.1.1 --- Adsorption kinetics --- p.87 / Chapter 5.1.2 --- Saturated adsorption capacity --- p.93 / Chapter 5.1.3 --- Saturated ethanol vapour adsorption volume --- p.94 / Chapter 5.1.4 --- Desorption --- p.96 / Chapter 5.2 --- Discussions --- p.99 / Chapter 5.2.1 --- Relationship between saturated ethanol vapor adsorption volumes and V[subscript psubscript osubscript rsubscript e] --- p.100 / Chapter 5.2.2 --- Comparison with other related works --- p.101 / Chapter 5.3 --- Conclusions --- p.103 / References --- p.104 / Chapter Chapter 6 --- Conclusions and Suggestions --- p.105 / Chapter 6.1 --- Conclusions --- p.105 / Chapter 6.2 --- Suggestions for future work --- p.106 / References --- p.107

Made available in DSpace on 2014-06-11T19:30:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-28Bitstream added on 2014-06-13T19:19:46Z : No. of bitstreams: 1 aguiar_af_dr_botib.pdf: 679778 bytes, checksum: c5aff2254c12cb4b62de64431ebf700b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Embora fortes evidências demonstrem que os fatores de regulação miogênica (MRFs) e o fator de crescimento semelhante à insulina (IGF-I) apresentem um importante papel na resposta hipertrófica após treinamento resistido (TR) agudo, permanece desconhecido se a resposta dos MRFs e IGF-I também ocorre durante a adaptação ao TR a longo-prazo. Portanto, o objetivo deste estudo foi testar a hipótese de que a resposta hipertrófica e modulação das fibras do músculo esquelético após TR a longo-prazo poderia estar associada ao aumento na expressão gênica dos MRFs e IGF-I. Ratos Wistar (80 dias de idade, 250-300 g) foram divididos em quatro grupos: Controle 8 semana (C8, n = 8), Treinado 8 semanas (T8, n = 8), Controle 12 semanas (C12, n = 8) e Treinado 12 semanas (T12, n = 8). Os grupos T8 e T12 foram submetidos a um programa de TR progressivo (3 dias/semana) durante 8 e 12 semanas, respectivamente. O protocolo de treinamento consistiu de quatro séries de 10-12 repetições, com um período de descanso de 40 segundos entre cada série, realizado a 65-75% de uma repetição máxima (1RM). Ao término do experimento, os animais foram sacrificados e o músculo plantar coletado para as análises morfológica e molecular. O TR durante 8 e 12 semanas não promoveu qualquer alteração (p > 0,05) significante no ganho de peso corporal e consumo alimentar dos grupos T8 e T12 em relação aos grupos C8 e C12, respectivamente. Após 8 e 12 semanas de TR, a força absoluta (T8: 69,7% and T12: 126,0%, p < 0,05) e relativa (T8: 36,1% and T12: 57,7%, p < 0,05) foi significantemente elevada nos grupos T8 e T12, em comparação aos seus respectivos controles. No entanto, houve um similar aumento da área de secção transversal (AST) das fibras musculares (T8: 29% vs. T12: 35%, p > 0,05) entre os grupos T8 e T12, comparados aos grupos C8 e C12, respectivamente... / Although strong evidence show that the myogenic regulatory factors (MRFs) and insulin-like growth factor (IGF-I) have important roles in the hypertrophy response after acute resistance training, it is still unclear if response of MRFs and IGF-I also occurs during the adaptation to prolonged periods of resistance training (RT). Therefore, the purpose of this study was to test the hypothesis that fiber-types transition and hypertrophy during long-term RT could be associated with increased MRFs and IGF-I mRNA expression in the skeletal muscle. Male Wistar rats (80 days old, 250-300 g) were divided into four groups: 8 weeks control (C8, n = 8), 8-weeks trained (T8, n = 8), 12-weeks control (C12, n = 8), 12-weeks trained (T12, n = 8). T8 and T12 groups were submitted to a progressive RT program (3 day/week) for 8 and 12 weeks, respectively. The training protocol consisted of four sets of 10–12 repetitions, with a 40 s rest period between each set, performed at 65–75% of one repetition maximum (1RM). At the end of the experiment, animals were sacrificed and the plantaris muscle collected for morphological and molecular analysis. The RT did not change (p > 0.05) in body weight gain and food intake in the T8 and T12 compared to the C8 and C12 groups, respectively. After 8 and 12 weeks of RT, the absolute (T8: 69.7% vs. T12: 126.0%; p < 0.05) and relative (T8: 36.1% vs. T12: 57.7%; p < 0.05) strength (relative 1RM) was significantly elevated in the T8 e T12 groups, compared to respective control groups. RT for 8 and 12 weeks induced similar increase in myogenin (T8: 44.8% vs. T12: 37.7%; p > 0.05), MyoD (T8: 22.9% vs. T12: 22.3%; p > 0.05) and muscle fiber crosssectional area (CSA) (T8: 29% vs. T12: 35%; p > 0.05) in the T8 and T12, compared to C8 and C12 groups, respectively. After 8 weeks of RT, IGF-I increased in 30.1% in the T8 compared to C8 group, but returned to baseline after 12 weeks... (Complete abstract click electronic access below)

An experimental investigation into the direct shear behaviour of steel fibre reinforced composites utilising discrete fibres at pre-defined angles and fibres randomly distributed is described. The direct shear tests encompassed the complete range of loading from its initial application to failure of the double L-shaped push-off specimens. Hooked-ended and straight steel fibres were used in the tests with the fibres oriented at angles of ??75??, ??60??, ??45??, ??30??, ??15?? and 0?? with respect to a plane normal to the loading direction. The embedment lengths of the fibres, related to the total fibre length lf , each side of the shear plane were 0.5lf :0.5lf and 0.25lf :0.75lf . In addition to the single fibre tests, tests were conducted on randomly oriented steel fibre reinforced composites with fibre volumes of 0.005, 0.010, 0.015, and 0.020 with hooked-ended and straight steel fibres. In addition to the tests outlined above, a series of non-destructive tests employing radiographic techniques was carried out to produce photographic images of events taking place of fibres pulling out from a cementitious element. The tests consisted of hooked-ended steel fibres oriented at angles of -60??, -30??, 0??, +30?? and +60?? to the cracking plane and straight fibres oriented at angles of -60??, 0?? and +60??. The non destructive technique allowed the internal behaviour occurring within the specimen along the shear plane to be investigated without impacting on the direct shear tests. The angle of the fibre to the interface plane is an important parameter in determining the behaviour of the fibres under load and for the mode of failure; viz fibre pullout or fibre fracture. The effect of the end hook on behavioural aspects becomes increasingly less significant for more acute fibre angles where bending and snubbing effects become increasingly influential on the load versus displacement behaviour and mode of failure. Contrary to expectations, the fibre embedment length had little influence over the peak loads attained for the discrete fibre tests and, in a number of specimens, fibres pulled out from the longer embedded side. This observation is contrary to the generally accepted assumption that a fibre remains rigidly embedded on the long side and pulls out from short side. The traditional role that uniform bond stresses along a fibre length and friction have played in the description of fibre behaviour is not as significant as previously reported, other effects such as snubbing are more important in anchoring a fibre. Various models need to be revised with this observation in mind. The experimental results and observations from the discrete hooked-ended and straight steel fibres investigation are incorporated in the development of a behavioural model, the Variable Engagement Model II (VEMII). The VEMII describes the behaviour of randomly oriented discontinuous steel fibre reinforced composites loaded in shear. The model is verified against a series of randomly distributed fibre reinforced mortar specimens carried out in this study. Two forms of models are analysed: 1) a model based on the observation of lumped shear stresses at the fibre hook and in the snubbing zone; and 2) a uniform fibre bond stress applied along the embedded part of the fibre. The lumped bond stress approach and the uniform approach were found to give reasonable comparisons with the test data for the hooked-ended fibres but were conservative for the straight fibres. The VEMII confirms the applicability of the uniform bond approach adopted by previous researchers even though it does not correspond to the observations of fibre pullout behaviour of single fibres. The VEMII model provides a versatile approach that can also be applied to hybrid fibre combinations.

An experimental investigation into the direct shear behaviour of steel fibre reinforced composites utilising discrete fibres at pre-defined angles and fibres randomly distributed is described. The direct shear tests encompassed the complete range of loading from its initial application to failure of the double L-shaped push-off specimens. Hooked-ended and straight steel fibres were used in the tests with the fibres oriented at angles of ??75??, ??60??, ??45??, ??30??, ??15?? and 0?? with respect to a plane normal to the loading direction. The embedment lengths of the fibres, related to the total fibre length lf , each side of the shear plane were 0.5lf :0.5lf and 0.25lf :0.75lf . In addition to the single fibre tests, tests were conducted on randomly oriented steel fibre reinforced composites with fibre volumes of 0.005, 0.010, 0.015, and 0.020 with hooked-ended and straight steel fibres. In addition to the tests outlined above, a series of non-destructive tests employing radiographic techniques was carried out to produce photographic images of events taking place of fibres pulling out from a cementitious element. The tests consisted of hooked-ended steel fibres oriented at angles of -60??, -30??, 0??, +30?? and +60?? to the cracking plane and straight fibres oriented at angles of -60??, 0?? and +60??. The non destructive technique allowed the internal behaviour occurring within the specimen along the shear plane to be investigated without impacting on the direct shear tests. The angle of the fibre to the interface plane is an important parameter in determining the behaviour of the fibres under load and for the mode of failure; viz fibre pullout or fibre fracture. The effect of the end hook on behavioural aspects becomes increasingly less significant for more acute fibre angles where bending and snubbing effects become increasingly influential on the load versus displacement behaviour and mode of failure. Contrary to expectations, the fibre embedment length had little influence over the peak loads attained for the discrete fibre tests and, in a number of specimens, fibres pulled out from the longer embedded side. This observation is contrary to the generally accepted assumption that a fibre remains rigidly embedded on the long side and pulls out from short side. The traditional role that uniform bond stresses along a fibre length and friction have played in the description of fibre behaviour is not as significant as previously reported, other effects such as snubbing are more important in anchoring a fibre. Various models need to be revised with this observation in mind. The experimental results and observations from the discrete hooked-ended and straight steel fibres investigation are incorporated in the development of a behavioural model, the Variable Engagement Model II (VEMII). The VEMII describes the behaviour of randomly oriented discontinuous steel fibre reinforced composites loaded in shear. The model is verified against a series of randomly distributed fibre reinforced mortar specimens carried out in this study. Two forms of models are analysed: 1) a model based on the observation of lumped shear stresses at the fibre hook and in the snubbing zone; and 2) a uniform fibre bond stress applied along the embedded part of the fibre. The lumped bond stress approach and the uniform approach were found to give reasonable comparisons with the test data for the hooked-ended fibres but were conservative for the straight fibres. The VEMII confirms the applicability of the uniform bond approach adopted by previous researchers even though it does not correspond to the observations of fibre pullout behaviour of single fibres. The VEMII model provides a versatile approach that can also be applied to hybrid fibre combinations.

An experimental investigation into the direct shear behaviour of steel fibre reinforced composites utilising discrete fibres at pre-defined angles and fibres randomly distributed is described. The direct shear tests encompassed the complete range of loading from its initial application to failure of the double L-shaped push-off specimens. Hooked-ended and straight steel fibres were used in the tests with the fibres oriented at angles of ??75??, ??60??, ??45??, ??30??, ??15?? and 0?? with respect to a plane normal to the loading direction. The embedment lengths of the fibres, related to the total fibre length lf , each side of the shear plane were 0.5lf :0.5lf and 0.25lf :0.75lf . In addition to the single fibre tests, tests were conducted on randomly oriented steel fibre reinforced composites with fibre volumes of 0.005, 0.010, 0.015, and 0.020 with hooked-ended and straight steel fibres. In addition to the tests outlined above, a series of non-destructive tests employing radiographic techniques was carried out to produce photographic images of events taking place of fibres pulling out from a cementitious element. The tests consisted of hooked-ended steel fibres oriented at angles of -60??, -30??, 0??, +30?? and +60?? to the cracking plane and straight fibres oriented at angles of -60??, 0?? and +60??. The non destructive technique allowed the internal behaviour occurring within the specimen along the shear plane to be investigated without impacting on the direct shear tests. The angle of the fibre to the interface plane is an important parameter in determining the behaviour of the fibres under load and for the mode of failure; viz fibre pullout or fibre fracture. The effect of the end hook on behavioural aspects becomes increasingly less significant for more acute fibre angles where bending and snubbing effects become increasingly influential on the load versus displacement behaviour and mode of failure. Contrary to expectations, the fibre embedment length had little influence over the peak loads attained for the discrete fibre tests and, in a number of specimens, fibres pulled out from the longer embedded side. This observation is contrary to the generally accepted assumption that a fibre remains rigidly embedded on the long side and pulls out from short side. The traditional role that uniform bond stresses along a fibre length and friction have played in the description of fibre behaviour is not as significant as previously reported, other effects such as snubbing are more important in anchoring a fibre. Various models need to be revised with this observation in mind. The experimental results and observations from the discrete hooked-ended and straight steel fibres investigation are incorporated in the development of a behavioural model, the Variable Engagement Model II (VEMII). The VEMII describes the behaviour of randomly oriented discontinuous steel fibre reinforced composites loaded in shear. The model is verified against a series of randomly distributed fibre reinforced mortar specimens carried out in this study. Two forms of models are analysed: 1) a model based on the observation of lumped shear stresses at the fibre hook and in the snubbing zone; and 2) a uniform fibre bond stress applied along the embedded part of the fibre. The lumped bond stress approach and the uniform approach were found to give reasonable comparisons with the test data for the hooked-ended fibres but were conservative for the straight fibres. The VEMII confirms the applicability of the uniform bond approach adopted by previous researchers even though it does not correspond to the observations of fibre pullout behaviour of single fibres. The VEMII model provides a versatile approach that can also be applied to hybrid fibre combinations.