Determining how atmospheric carbon dioxide concentrations have changed during the history of the Earth

The reconstruction of ancient atmospheric carbon dioxide concentrations is essential to understanding the history of the Earth and life. It is also an important guide to identifying the sensitivity of the Earth system to this greenhouse gas and, therefore, constraining its future impact on climate. However, determining the concentration of CO2 in ancient atmospheres is a challenging endeavour requiring the application of state-of-the-art analytical chemistry to geological materials, underpinned by an understanding of photosynthesis and biochemistry. It is truly an interdisciplinary challenge

A novel membrane bioreactor configuration for nitrogen removal

Population growth in the U.S. and abroad has led to a need for increased treatment of wastewater to limit the effects of additional pollution loadings on bodies of water. Additionally, this need is complicated by limitation on energy inputs. The solution is treatment reactors that are robust, simple to operate, effective in treatment, and energy efficient. This research will compare a traditional membrane bioreactor configuration with a design meant to address these issues. The proposed configuration used differences in hydraulic head to move liquor from a pre-anoxic zone to the aerobic zone and return a portion of it to the pre-anoxic zone for biological denitrification. The benefits of this design were suspected to be increased nitrogen removal while minimizing energy inputs. This unique configuration consisted of one blower, pumps to induce pressure differentials for membrane operation, and a single mechanical mixer for mixing the anoxic zone and providing hydraulic lift. Complete data sets for both reactors are presented, and the results from the reactors are compared using data that coincides with operation over the same dates (i.e., summer of 2009 and 2010). Efficacy of the reactors is judged based on their mass and volumetric removal rates. This research resulted in a potentially viable reactor design that increases nitrogen removal over a conventional MBR while reducing the number of pumps needed for operation --Abstract, page iii

Perceptions of Educational Equality in Tennessee: A Comparison of City School Systems vs. County School Systems in Northeast Tennessee.

The majority of city and county school systems throughout Tennessee and the United States at one time or another experience a budget crisis. In the state of Tennessee, school systems are funded through the Basic Education Program, established in 1992 as part of the Tennessee Education Improvement Act. The lawsuit of 1988, Tennessee Small School Systems v. McWherter, created the Basic Education Program. Through the years, the Basic Education Program has provided extra teaching positions, materials, and supplies and has provided the funding formula for school systems throughout the state. Many high-ranking administrators contend that the Basic Education Program has outlasted its time. School administrators from both city and county school systems indicate the program needs to be restructured to meet the current needs of the schools and students throughout the state of Tennessee. The purpose of this mixed-method study was to explore the perceptions of educational equality and the advantages/disadvantages of the Basic Education Program. Through quantitative data, city and county school systems were compared for per-pupil spending, average teacher salary, and student achievement in the advanced proficient category for math and reading/language. These data were collected from the Tennessee Department of Education website and the Tennessee Education Association website. Qualitative data were collected through interviews with high-ranking administrators from city and county school systems in Northeast Tennessee. These administrators were purposively selected from systems containing both city and county schools. The findings of this study demonstrated that city school systems have higher per-pupil spending and higher teacher salaries than county systems. City school systems have higher student achievement levels in the advanced proficient category than county school systems. Interview participants agree that educational equity does not exist between city and county school systems in the state of Tennessee. The participants in this study express that although the Basic Education Program in Tennessee was effective, at one time, it should be restructured or redefined to meet the current needs of all students in the state of Tennessee

An opportunity for system dynamics in manufacturing system modelling

The computer simulation of manufacturing systems is commonly carried out using discrete event simulation (DES). Indeed, there appears to be a lack of applications of continuous simulation methods, particularly system dynamics (SD), despite evidence that this technique is suitable for industrial modelling. This paper investigates whether this is due to a decline in the general popularity of SD, or whether modelling of manufacturing systems represents a missed opportunity for SD. On this basis, the paper first gives a review of the concept of SD and fully describes the modelling technique. Following on, a survey of the published applications of SD in the 1990s is made by developing and using a structured classification approach. From this review, observations are made about the application of the SD method and opportunities for future research are suggested

A multinuclear magnetic resonance study of vanadium (V) complexes and equilibria

The use of high-field n.m.r. spectroscopy to study the aqueous chemistry of vanadium(V) has yielded information not only about the species present but, also, a qualitative understanding of the ¹⁷O n.m.r. chemical shifts in polyanions. The peroxo and sulphido complexes of vanadium(V) are reported as well as the interaction of vanadate with ADP and ATP, and oxygen exchange in the polyanion tetradecavanadophosphate (9-) ([PV₁₄O₄₂]⁹ˉ). In general, peroxovanadate complexes tend to contain two peroxide ligands per vanadium, although some mono-, tri- and tetraperoxovanadates are found. The mono- and diperoxovanadates undergo a change in co-ordination from octahedral to tetrahedral on removal of their final proton (˜pH 14). Four new dimeric species have been observed, three of which are unsymmetrical. The pH-dependent differential rates of oxygen exchange of tetradecavanadophosphate (9-) can be explained in terms of the stabilisation of the anion by the two pentaco-ordinate VO caps with respect to the "equator" of the Keggin type structure. The four half-hemisphere units resist exchange. Bulk distortions of this anion and decavanadate (6-) can be deduced from the observation of their ¹⁷O chemical shifts with pH. The three known sulphido and oxosulphido- vanadium(V) species [VS₄]ᶟˉ, [VOS₃]ᶟˉ and [VO₂S₂]ᶟˉ have been identified by high-field vanadium-51 n.m.r., together with the previously unobserved ions VO₃S]ᶟˉ, [V₂S₇]⁴ˉ, [O₃VSVO₃]⁴ˉ, [SO₂VSVO₂S]⁴ˉ and the protonated monomers. No equilibria between monomeric species are observed other than for protonation. Vanadate complexes with the polyphosphate chain in both ATP and ADP, probably as [VO₂]⁺ bridging two adjacent phosphates. Exchange with species containing [VO₃]ˉ bound to the terminal phosphate and, in ATP only, "[VO]ᶟ⁺ bound to all the phosphates may occur

Measuring the Gap and Investigating Non-equilibrium in the BEC-BCS Crossover

This thesis presents a new Bose-Fermi mixture quantum gas experiment that has been used to measure the gap over the BEC-BCS crossover and investigate the non-equilibrium dynamics of a superfluid in response to a quench of the interaction strength. Bosonic 23Na sympathetically cools fermionic 6Li in an optically plugged magnetic trap before transferring the atoms to an optical dipole trap. The broad Feshbach resonance of 6Li is then used to tune the scattering length and by entering the strongly interacting regime, very efficient evaporation can be performed. Bose-Einstein condensation of molecules with over 5×1066Li atoms per spin state has been observed and temperatures T/TF=0.07±0.02 have been achieved. The broad Feshbach resonance of 6Li can then be used to bring the atoms into the BCS regime, where long range Cooper pairs of opposite spin and momentum form a superfluid state, or into the universality regime, where the scattering length diverges and the system obeys universal laws. A technique was developed whereby the population of one component of the superfluid was continuously modulated with a specific frequency. Theoretical studies show that this excitation couples to the amplitude/Higgs mode of the superfluid order parameter, which should have a resonance frequency at twice the gap value. By measuring the response of the condensate fraction at various modulation frequencies, a measure of the gap in the BEC-BCS crossover could be extracted. The measured gap value was found to be in agreement with the mean-field theory calculations and quantum Monte Carlo simulations. Extending the same method, it was possible to rapidly change one of the components of a superfluid to a different third component. The inversion was performed in less than 50μm, faster than the dynamical gap time and quasiparticle relaxation time. This provides an excellent realization of the fast quenches of the interaction strength that have been intensely investigated theoretically. By quenching a strongly interacting superfluid to much weaker interactions, the decay of the order parameter was studied. During these non-equilibrium dynamics, evidence of a revival of the order parameter has been observed at longer time scales for weak quenches. Additionally, a weakly interacting normal mixture above the critical temperature can be quenched to interaction strengths where, in equilibrium, a superfluid should be present. The emergence of the order parameter was measured as a function of time and was found to be faster for weak quenches into the BCS regime than for larger quenches into unitarity

Towards sustainable public engagement (outreach)

There are myriad benefits to science departments that have a public engagement in science portfolio in addition to any recruitment of new undergraduates. These benefits are discussed in this paper and include: improving congruence between A level and first year undergraduate courses, training in science communication and the breaking down of barriers between the public and universities. All activity requires investment of personnel and incurs a financial cost. Small scale activities may be able to absorb this cost, but ultimately as the portfolio grows this will become an increasing drain on resources. Bristol ChemLabS Outreach has, from the very start, set out to be fully sustainable financially and in terms of personnel. A very important component is the full support of the senior management team. In this paper we discuss how we have achieved this

Wobble Stories as Reflective Practice: Learning through Struggle

As educators, we need to provide opportunities for students to critically analyze multiple viewpoints that can challenge them as a way to help them see value in learning and developing. University classrooms are a place for fostering, developing, and practicing strategies for navigating moments of Wobble through discussion and reflection