Metabolism is a key attribute of life on Earth at multiple spatial and temporal scales, involved in processes ranging from cellular reproduction to biogeochemical cycles. While metabolic network modeling approaches have enabled significant progress at the cellular-scale, extending these techniques to address questions at both the ecosystem and planetary-scales remains highly unexplored. In this thesis, I integrate various multi-scale metabolic network modeling approaches to address key questions with regard to both the long-term evolution of metabolism in the biosphere and the metabolic processes that take place in complex microbial communities. The first portion of my thesis work, focused on the evolution of ancient metabolic networks, attempts to model the emergence of ecosystem-level metabolism from simple geochemical precursors. By integrating network-based algorithms, physiochemical constraints, and geochemical estimates of ancient Earth, I explored whether a complex metabolic network could have emerged without phosphate, a key molecular component in modern-day living systems, known to be poorly available at the onset of life. We found that phosphate may have not been essential in early living systems, and that thioesters may have been the primitive energy currency in ancient metabolic networks. By generalizing this approach to explore the scope of geochemical scenarios that could have given rise to living systems, I found that other key biomolecules, including fixed nitrogen, may have not been required at the earliest stages in biochemical evolution. The second portion of my thesis deals with a different aspect of ecosystem-level metabolism, namely the role of metabolism in shaping the structure of microbial communities. I studied the relationship between metabolism and microbial community assembly using microbial communities grown in synthetic laboratory environments. We found that a generalized statistical consumer-resource model recapitulates the emergent phenomena observed in these experiments. Future work could seek to better clarify the connection between the fundamental rules that led to life’s emergence over 4 billion years ago and the laws that shape microbial ecosystems today. An ecosystems-level metabolic perspective may aid in our understanding of both the emergence and maintenance of the biosphere.

Zhao, Xiaozheng = 滑移邊界條件下湍流熱對流的實驗研究 / 趙晓争. / "September 2010." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 52-57). / Abstracts in English and Chinese. / Zhao, Xiaozheng = Hua yi bian jie tiao jian xia tuan liu re dui liu de shi yan yan jiu / Zhao Xiaozheng. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgement --- p.iv / Contains --- p.iv / List of Figures --- p.vii / List of Tables --- p.xi / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Turbulence --- p.1 / Chapter 1.2 --- Turbulent Rayleigh-Benard Convection --- p.2 / Chapter 1.2.1 --- Physical Picture --- p.2 / Chapter 1.2.2 --- Governing Equations and Characteristic Parameters --- p.5 / Chapter 1.2.3 --- Nu Scaling --- p.7 / Chapter 1.2.4 --- Boundary Layer --- p.8 / Chapter 1.3 --- Motivations of the Present Work --- p.10 / Chapter 2 --- Experimental Setup --- p.13 / Chapter 2.1 --- The Convection Cell --- p.13 / Chapter 2.2 --- Temperature Probe and Translation Stage --- p.15 / Chapter 2.3 --- Calibration of the Thermistors --- p.17 / Chapter 2.4 --- Data Acquisition Units --- p.18 / Chapter 2.5 --- The Working Fluids --- p.19 / Chapter 2.6 --- Heat Leakage Prevention --- p.21 / Chapter 3 --- Heat Transfer and Thermal Boundary Layer Measurement --- p.23 / Chapter 3.1 --- The Setup and Experimental Procedure --- p.23 / Chapter 3.2 --- The Mean Temperature and Temperature Fluctuation Profiles across the Interfaces --- p.24 / Chapter 3.2.1 --- Profiles across the Water-FC77 Interface --- p.24 / Chapter 3.2.2 --- Profiles across the FC77-Mercury Interface --- p.27 / Chapter 3.3 --- Nu Results --- p.29 / Chapter 3.3.1 --- Results Obtained with Assumption of Pure Conduction --- p.30 / Chapter 3.3.2 --- Results from Mean Temperature Profile --- p.32 / Chapter 3.3.3 --- Comparison of the Two Methods --- p.33 / Chapter 3.4 --- Boundary Layer Thickness --- p.37 / Chapter 3.5 --- Summary --- p.39 / Chapter 4 --- Influence of Flow in the Water (Mercury) Layer on the FC77 Layer --- p.41 / Chapter 4.1 --- Experimental Setup --- p.41 / Chapter 4.2 --- Main Results --- p.42 / Chapter 4.3 --- Probability Density Function and Temperature Oscillation --- p.44 / Chapter 4.4 --- Summary --- p.50 / Chapter 5 --- Conclusions and Perspective --- p.51 / Chapter 5.1 --- Conclusions --- p.51 / Chapter 5.2 --- Perspective for Future Work --- p.52

Cai, Debin = 高普朗特數湍流對流中速度場和溫度場能量級串傳遞的實驗研究 / 蔡德斌. / "September 2010." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (p. 84-88). / Abstracts in English and Chinese. / Cai, Debin = Gao pu lang te shu tuan liu dui liu zhong su du chang he wen du chang neng liang ji chuan chuan di de shi yan yan jiu / Cai Debin. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.ii / Acknowledgements --- p.iii / Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.xv / Chapters / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Turbulence --- p.1 / Chapter 1.2 --- Turbulent Rayleigh-Benard Convection --- p.2 / Chapter 1.3 --- Small-Scale Properties of Turbulent Convection --- p.6 / Chapter 1.4 --- Motivations and structure of this thesis --- p.9 / Chapter 1.4.1 --- Motivations --- p.9 / Chapter 1.4.2 --- Organization of this thesis --- p.15 / Chapter 2. --- Experimental apparatus and techniques --- p.16 / Chapter 2.1 --- Turbulent Rayleigh-Benard convection cell --- p.16 / Chapter 2.2 --- The working fluid 1-Pentanol --- p.20 / Chapter 2.3 --- Technique and instruments in temperature structure function measurement --- p.21 / Chapter 2.3.1 --- Temperature detecting probe --- p.22 / Chapter 2.3.2 --- Electronic instruments for temperature measurement --- p.25 / Chapter 2.4 --- Technique and instruments in velocity structure function measurement --- p.28 / Chapter 3. --- Cascades of Temperature Fluctuations in High Prandtl Number Turbulent Convection --- p.31 / Chapter 3.1 --- Selection of the experimental parameters --- p.31 / Chapter 3.2 --- Temperature structure function at the cell centre --- p.33 / Chapter 3.2.1 --- Experiment arrangements --- p.34 / Chapter 3.2.2 --- Experiment results of temperature structure function at the cell centre --- p.37 / Chapter 3.3 --- Temperature structure function near the cell sidewall --- p.43 / Chapter 3.4 --- Intermittency in the high Pr number system --- p.49 / Chapter 3.5 --- Summary --- p.51 / Chapter 4. --- Cascades of Velocity Fluctuations in High Prandtl Number Turbulent Convection --- p.52 / Chapter 4.1 --- Experiment technique --- p.52 / Chapter 4.2 --- Velocity structure function at the cell centre --- p.54 / Chapter 4.2.1 --- Analysis with time average method only --- p.55 / Chapter 4.2.2 --- Homogeneity and isotropy at the cell centre --- p.61 / Chapter 4.2.3 --- Analysis with spatial average method --- p.65 / Chapter 4.3 --- Velocity structure function near the sidewall --- p.70 / Chapter 4.4 --- Summary --- p.75 / Chapter 5. --- Comparison between Different Experiments --- p.77 / Chapter 5.1 --- Comparison between High and Low Pr Number Cases --- p.77 / Chapter 5.2 --- Comparison between the Temperature and Velocity Structure Function Measurements in High Pr number System --- p.80 / Chapter 6. --- Conclusion --- p.82 / References --- p.84

This discussion paper looks at the connections between economies and ecosystems, or more generally biophysical reality. The term "economies" is used, rather than "the economy", because of the prevalent false claim that there is only one type of economic system that is possible. We outline how the ecological crises is linked to the dominant drive for economic growth and the tendency to equate growth with progress and development; common even amongst those apparently critical of the need for continued growth in the materially rich countries. The unreality of mainstream economics is epitomised by the accolades given to those justifying mild reformist policy in response to human induced climate change in order to continue the pursuit of economic growth. We emphasise the structural aspects of economies as emergent from and dependent upon the structure and functioning of both society and ecology (energy and material flows). Finally, that the structure of the global economy must change to avoid social ecological collapse, poses the questions of how that can be achieved and what sort of economics is necessary? We explain the need for: (i) a structural change that addresses the currently dysfunctional relationships between economic, social and ecological systems, and (ii) an economics that is interdisciplinary and realist about its social and natural science relations. / Series: SRE - Discussion Papers

Photocopy of typescript. / Digitized by Kansas Correctional Industries

In this thesis we accomplish two goals: We construct a two dimensional conformal field theory (CFT), in the form of a Liouville theory, in the near horizon limit for three and four dimensions black holes. The near horizon CFT assumes the two dimensional black hole solutions that were first introduced by Christensen and Fulling (1977 Phys. Rev. D 15 2088-104) and later expanded to a greater class of black holes via Robinson and Wilczek (2005 Phys. Rev. Lett. 95 011303). The two dimensions black holes admit a $Diff(S^1)$ or Witt subalgebra, which upon quantization in the horizon limit becomes Virasoro with calculable central charge. These charges and lowest Virasoro eigen-modes reproduce the correct Bekenstein-Hawking entropy of the four and three dimensions black holes via the Cardy formula (Bl"ote et al 1986 Phys. Rev. Lett. 56 742; Cardy 1986 Nucl. Phys. B 270 186). Furthermore, the two dimensions CFT's energy momentum tensor is anomalous, i.e. its trace is nonzero. However, In the horizon limit the energy momentum tensor becomes holomorphic equaling the Hawking flux of the four and three dimensions black holes. This encoding of both entropy and temperature provides a uniformity in the calculation of black hole thermodynamics and statistical quantities for the non local effective action approach. We also show that the near horizon regime of a Kerr-Newman-$AdS$ ($KNAdS$) black hole, given by its two dimensional analogue a la Robinson and Wilczek, is asymptotically $AdS_2$ and dual to a one dimensional quantum conformal field theory (CFT). The $s$-wave contribution of the resulting CFT's energy-momentum-tensor together with the asymptotic symmetries, generate a centrally extended Virasoro algebra, whose central charge reproduces the Bekenstein-Hawking entropy via Cardy's Formula. Our derived central charge also agrees with the near extremal Kerr/CFT Correspondence in the appropriate limits. We also compute the Hawking temperature of the $KNAdS$ black hole by coupling its Robinson and Wilczek two dimensional analogue (RW2DA) to conformal matter.

Composting has been practiced for thousands of years as a way of stabilizing and recycling organic matter into useful soil amendments. Thermophilic compost releases significant amounts of heat at temperatures (~140 °F) that are useful for environmental heating or process water. This heat has been taken advantage of in various ways throughout history, but development of a widely adopted technology remains elusive. The biggest barrier to adoption of compost heat recovery (CHR) systems is projecting accurate, attractive economic returns. The cost of transfer equipment is significant, and with variability in composting substrates and methods, it is difficult to predict the power and quality of heat a proposed system would produce. While the ultimate heat release may be calculated with standard techniques, the dynamics of compost temperature and thermal power are less understood. As heat yield is one of many goals, better understanding of compost’s thermal dynamics is important for CHR optimization. This research addresses the issue by developing a field test that measures heat release and temperature across a representative-scale compost volume. The compost test vessel was built from common construction materials and insulated enough to be self-heating in cold weather. A 4’ x 4’ x 4’ cube of 2” foam insulation panels held 1.812 cubic yards of active compost, intermittently aerated at ~35 CFM. Data from 84 temperature sensors, and one pressure sensor at the blower, was logged at 1-minute intervals for a period of 35 days. Spatial temperature fields were estimated by Kriging, and used to calculate conductive heat loss and compost volume temperature over time. Enthalpy loss was calculated using the blower pressure curve, temperature data and humidity assumptions. The compost exhibited wide variation in temperature and heat flow over time, and less horizontal symmetry than expected. The results are dynamic and best viewed graphically. Enthalpy loss varied with adjustments to the aeration cycle, ranging from 100 to 550 W (60-minute average rates), while conductive losses were in the range of 75 W. Peak sustained thermal output was around 600 W (500 W by aeration) from days 11-13 with about 0.6 yd3 of compost in the thermophilic zone; however, this cooled the compost significantly. Aeration was then reduced, and the compost temperature recovered, with 50% - 90% of the compost volume above 130 °F from days 14-23; during this period, total heat loss was around 150 - 200 W with aeration loss around 60-100 W. The test was successful in producing hot compost and building temperature field and heat loss models. However representative aeration rates cooled a large amount of the compost volume as cool air was drawn into the vessel. Aeration rate reduction accomplished desired compost temperatures, but resulted in low enthalpy extraction rate and temperature. Future work will address this issue with the ability to recirculate air through the compost.

Abstract Zinc is a common metal, and has a central role in the production of galvanised bulk products, battery applications and fertilisers. Its production relies mainly on the leaching of zinc minerals with sulfuric acid, followed by purification and electrowinning. In this thesis an internally consistent thermodynamic model for the industrially important ZnSO₄-H₂SO₄-H₂O system was developed. Model parameters were optimised using available literature data and new experimental freezing point and density data determined in this work. With Gibbs energy minimisation algorithms embedded in commercial software, such as ChemSheet and FactSage, the developed model can be used to calculate easily phase equilibria and thermodynamic properties of aqueous zinc sulfate solutions and solid zinc sulfate phases, including activity coefficients, enthalpy changes, heat capacities, densities and solubilities, in a wide range of temperature, pressure and sulfuric acid concentrations. Solution non-ideality was treated with the original Pitzer model with electrostatic mixing terms included. Applicability of thermodynamic approach and the developed model was demonstrated by two separate case studies on the hydrometallurgical zinc process. Precipitation of amorphous silica during hot acid leach was studied experimentally. Its solubility in the process solution was also successfully predicted using the thermodynamic approach. To study crystallisation of gypsum during the gypsum precipitation stage, the model was expanded by addition of the Ca²⁺ ion. The model calculations showed good agreement with the experienced Ca²⁺ levels. The results of this thesis have found immediate use in understanding the various stages of the electrolytic zinc process. The obtained results also form a basis on which new, more advanced tools for managing and studying the process can be developed. / Tiivistelmä Sinkki on yleinen metalli, ja sillä on keskeinen rooli sinkittyjen terästuotteiden, paristojen ja jopa lannoitteiden valmistuksessa. Sen tuotanto perustuu sinkkipitoisten mineraalien rikkihappoliuotukseen, muodostuneen prossessiliuoksen puhdistukseen ja lopulta metallisen sinkin elektrolyysitalteenottoon. Tässä työssä kehitettiin termodynaaminen malli teollisesti tärkeälle ZnSO₄-H₂SO₄-H₂O -systeemille. Malliparametrit määritettiin kirjallisuudessa esitetyistä tuloksista ja tässä työssä tehdyistä uusista jäätymispiste- ja tiheysmittauksista. Käyttämällä kaupallisia Gibbsin energian minimointialgoritmiin perustuvia ohjelmistoja, kuten ChemSheet tai FactSage, tässä työssä kehitetyllä mallilla voidaan helposti kuvata sinkkisulfaattipitoisten vesiliuosten faasitasapainoja ja laskea systeemin termodynaamisia ominaisuuksia. Malliin sisällytettyihin ominaisuuksiin kuuluvat systeemin komponenttien aktiivisuudet, entalpiamuutokset, lämpökapasiteetit sekä tiheydet laajalla lämpötila-, paine- ja rikkihapon pitoisuusalueella. Liuoksen epäideaalisuutta kuvattiin Pitzerin ioniaktiivisuusmallilla. Työssä sinkkisulfaattiliuoksille kehitettyä mallia testattiin kahdessa sinkintuotannon kannalta keskeisessä tapaustutkimuksessa. Amorfisen piidioksidin saostumista vahvahappoliuotuksen aikana tutkittiin kokeellisesti ja laskennallisesti. Amorfisen piidioksidin liukoisuus prosessiliuokseen ennustettiin onnistuneesti. Kipsinpoistoprosessin tutkimusta varten mallia laajennettiin lisäämällä siihen Ca²⁺-ioni. Mallilla laskettiin kipsin liukoisuus prosessiliuokseen. Saadut tulokset vastasivat hyvin käytännössä havaittuja arvoja. Tutkimuksen tuloksia on suoraan hyödynnetty sinkintuotantoprosessin ymmärtämisessä. Ne myös mahdollistavat jatkossa edistyneempien työkalujen kehittämisen niin prosessin hallintaan kuin tutkimukseenkin.

The objective of this investigation was to study the effect of chemical competition on thermodynamics of bacterial adsorption. This was done using an experimental system consisting of Mendon silt loam soil as the adsorbent, Staphylococcus aureus as a common adsorbate and sodium chloride (NaCl), sodium lauryl sulfate (SLS), and peptone as competitive adsorbates. The bacterial adsorption on soil both with and without chemical competition followed Langmuir type isotherms. From the equilibrium data, thermodynamic functions such as free energy, ΔF°, enthalpy, ΔH°, and entropy, ΔS°, were calculated. Observed positive ΔH° values indicated that the bacterial uptake in both noncompetitive and competitive environments is endothermic. Bacteria and soil both have a negative charge. A positive ΔH° value is attributed to the repulsion between the bacteria and soil particles. For a non-competitive system, the observed ΔH° value was 8.50 kcal-mole-1. Relatively higher ΔH° values were obtained in the presence of peptone and NaCl. These values were 24.0 kcal-mole-1 and 23.0 kcal-mole-1 for peptone and NaCl respectively, suggesting that the bacterial uptake is much more endothermic in the presence of these chemicals. The lower ΔH° value (3.72 kcal-mole-1) observed in the presence of SLS indicated that bacterial adsorption is relatively less endothermic in the presence of such a chemical. In all the sorbent-sorbate systems studied, observed ΔS° values were positive indicating that the bacteria are more disordered in the adsorbed phase than they are in the solution phase. Observed ΔF° values for all the adsorption systems were negative, indicating that the bacterial adsorption in both competitive and noncompetitive environments is spontaneous.

Phosphorus has long been recognized by agriculturists as being one of the elements essential for plant growth. Although the total phosphorus content of a soil may be high, the amount of phosphate actually available for plant growth is often low. Many agencies such as inherent low solubilities of phosphate compounds, adsorption on Ca C03, adsorption in the diffuse double layer of clay micelles, and chemical precipitation of phosphate which refers to the removal of phosphate ions from solution and their chemical bonding to the solid phase have been studied to explain the lack of phosphate availability.