Testing General Free Functions in Preferred Scale Theories

Building on previous work, we explore the parameter space of general free functions in non-relativistic modified gravity theories motivated by k-essence and other scalar-tensor theories. Using a few proposed tests, we aim to update Solar System based constraints on these ideas in line with previous theories and suggest their utility in constraining modification to GR, potentially even being able to test k-essence type theories.Comment: 8 page

Theoretical and Experimental Constraints on Modified Gravity

In this thesis, we consider techniques to characterise a Solar System test for modified gravity theories with an inherent preferred acceleration scale (reducing to MOdified Newtonian Dynamics (MOND) in its non-relativistic limit). We further explore the use of measurements from the forthcoming LISA Pathfinder mission to test these theories. Employing gravitational wave techniques such as the expected signal-to-noise ratio as well as considering effects from a variety of instrumental noise models, saddle trajectories and systematics such as self gravity, we show such a test appears very viable. The possibility of constraints in the event of a null result is explored, as well as designing free functions to evade such a test. The symmetries present in such a scheme allowed us to we develop a simple algorithm for scaling tidal stresses in the event of parameters a_0 and k assuming values different to those originally considered (short cutting a lot of computational work). In doing so, we are able to show broadly, that the scaling of parameters (within an order of magnitude) could potentially save or slaughter a dubious result. Similarly constraints from fifth force experiments and bounds on anomalous accelerations on solar system scales could feed into our theories, but these would appear as parameters in the (otherwise unconstrained) free function \mu. We present a similar scaling algorithm to rescale results previously computed from a particular \mu, as well as look at methods to constrain it from data. We also explore the behaviour of previously poorly constrained parameters, such as the MONDian scaling C and its behaviour between models. We also extend our formalism to investigate results from more general free functions, perhaps resulting from scalar tensor or other modified gravity theories.Open Acces

Molybdenum and arsenic behavior in a limestone aquifer in Central Florida

The mobilization of geogenic molybdenum (Mo) and arsenic (As) from the aquifer matrix sediments in Central Florida, USA has resulted in the contamination of groundwater and irrigated soils. The aquifer matrix contained up to 825 mg/kg Mo and 144 mg/kg As. The concentrations of Mo and As in groundwater reached up to 5000 AA g/L and 300 AA g/L which exceed the WHO guidelines of 70 AA g/L and 10 AA g/L, respectively. In this research, in order to evaluate the potential of Mo and As as contaminants in the aquifer matrix sediments, chemical fractionation, primary sources, and the adsorption/desorption behavior of Mo and As by/from hydrous ferric oxide (HFO) were studied. The adsorption of Mo onto organic matter (OM) was also investigated to determine its role in removing Mo from groundwater. First, a five step sequential extraction procedure (SEP) was applied to 10 aquifer matrix samples which were chosen from three cores near Lithia village in Central Florida. Then, the chromium-reducible sulfur (CRS) method was used to assess the primary sources of Mo and As. This particular method was used to determine the relationship between reduced sulfur including inorganic reduced sulfur such as sulfur content in pyrite (FeS2) and organic sulfur (OS) and the trace elements (Mo and As) in the aquifer matrix. Finally, to assess the adsorption and desorption of Mo and As by/from HFO and humic acid (HA), a combination of batch experiments with HFO, HA and the aquifer matrix sediments were conducted. The results of SEP showed that Mo was mainly present in the soluble fraction (step 1). For six samples, more than 80%, for two samples more than 50% and for two samples up to 20% Mo was released during the first step. About 10% Mo was leached during steps 2 and 3, which dissolve carbonates, HFO, manganese oxides and powellite (CaMoO4). Approximately 25% of Mo bounded to crystalline iron oxides, pyrite and OM in steps 4 and 5. In contrast to Mo, As was present in all the extractiona s steps in somewhat similar abundances: step 1 (17%), step 2 (11%), step 3 (30%), step 4 (23%) and step 5 (18%). Hydrous and crystalline iron oxides, which were dissolved in steps 3 and 4 contained the highest As concentrations. From this procedure, it became clear that compared to As, Mo is more easily released from the aquifer matrix. Pyrite and OM which were present in both aquifer matrix sediments underlying Lithia area and in Avon Park Formation (APF), were generally considered as source for Mo and As. To evaluate this statement, a total of 24 samples (including 10 samples which were already subjected to SEP analysis) were chosen from Lithia area and APF. The samples were selected based on the following four criteria: (1) high total Mo concentration, (2) high total As concentration, (3) high total sulfur concentration, and (4) good geographic representation of the study area. The results of CRS did not confirm the presence of Mo in pyrite in the Lithia area, though it was shown to exist as a minor constituent in the APF. The total organic carbon content in the residues of CRS (OCres) method was positively correlated to Mo (R2 = 0.71 and p 0.001). There was no correlation between OS and Mo. Compared to Mo, As concentration in pyrite was much higher, pointing to pyrite as a major primary source for As in the aquifer matrix sediments. There was a weak correlation between As and OCres. The results suggested that the Mo found in the aquifer matrix and groundwater was mainly sourced from OM rather than pyrite, whereas As originated mainly from pyrite as a primary source, in addition to iron oxides in the adsorbed forms. The adsorption and desorption of Mo and As by/from HFO and HA indicated that HFO was not a major sink for Mo but a significant secondary source for As. Molybdenum sorption onto HFO mainly happened by the formation of inner-sphere complexes. Arsenic(III) and As(V) sorption onto HFO resulted in inner-sphere complexes. Oxygenated water had no significant effect on the mobilization of Mo and As from the aquifer matrix in the Lithia area and APF. Powellite could be considered as a minor secondary source for Mo and As. In the alkaline pH ranges (pH ranges of the study area), the adsorption of Mo on HA was too low

The curious case of the Iran nuclear deal : a practice approach to understanding norm productivity of diplomacy

Iran’s nuclear programme has long been a nuclear proliferation controversy. In 2015, a historic agreement, the Joint Comprehensive Plan of Action (JCPOA), was achieved that addressed the international community’s concerns about Iran’s nuclear programme. In 2018, however, the US pulled out of JCPOA. Much to the surprise of many, JCPOA did not immediately fall apart. In fact, JCPOA persisted for quite a long time. I made a hypothetical distinction between JCPOA as a material agreement, and JCPOA as a norm to explain the unexpected survival of JCPOA. In order to substantiate my claim, I foregrounded the role of diplomacy in the production and reproduction of JCPOA as a norm. I drew on post-structuralist and social constructivist elements as well as constructivist norm scholarship to inform my empirical analysis. My empirical analysis comprised two main parts. In the first part, I focused on diplomatic practices that took place from 2015 to 2016 corresponding to the time JCPOA was achieved until the implementation day. I identified discursive traces in the diplomatic practices that could contribute to constructing JCPOA as a norm. In the second part, I identified the patterns in the diplomatic practices that were involved in the reproduction of JCPOA as a norm, even though the contestations were building up progressively during the second time span from 2017 to 2020. I presented an innovative explanation for the surprising survival of JCPOA. I demonstrated that diplomatic practices were involved in the production and reproduction of JCPOA as a norm which in turn helped it persist against the contestations. I also uncovered a cooperative relationship between these diplomatic practices, and the structural/material factors in norm productivity. The findings of this thesis provide empirical insights into understanding the constitutive and agentic capacity of diplomacy. This thesis supports the non-instrumentalist/critical view of diplomacy as opposed to the instrumentalist/rationalist view. It is concluded that diplomacy in itself can be consequential for world politics.submittedVersionM-I

Molybdenum and arsenic behavior in a limestone aquifer in Central Florida

The mobilization of geogenic molybdenum (Mo) and arsenic (As) from the aquifer matrix sediments in Central Florida, USA has resulted in the contamination of groundwater and irrigated soils. The aquifer matrix contained up to 825 mg/kg Mo and 144 mg/kg As. The concentrations of Mo and As in groundwater reached up to 5000 AA g/L and 300 AA g/L which exceed the WHO guidelines of 70 AA g/L and 10 AA g/L, respectively. In this research, in order to evaluate the potential of Mo and As as contaminants in the aquifer matrix sediments, chemical fractionation, primary sources, and the adsorption/desorption behavior of Mo and As by/from hydrous ferric oxide (HFO) were studied. The adsorption of Mo onto organic matter (OM) was also investigated to determine its role in removing Mo from groundwater. First, a five step sequential extraction procedure (SEP) was applied to 10 aquifer matrix samples which were chosen from three cores near Lithia village in Central Florida. Then, the chromium-reducible sulfur (CRS) method was used to assess the primary sources of Mo and As. This particular method was used to determine the relationship between reduced sulfur including inorganic reduced sulfur such as sulfur content in pyrite (FeS2) and organic sulfur (OS) and the trace elements (Mo and As) in the aquifer matrix. Finally, to assess the adsorption and desorption of Mo and As by/from HFO and humic acid (HA), a combination of batch experiments with HFO, HA and the aquifer matrix sediments were conducted. The results of SEP showed that Mo was mainly present in the soluble fraction (step 1). For six samples, more than 80%, for two samples more than 50% and for two samples up to 20% Mo was released during the first step. About 10% Mo was leached during steps 2 and 3, which dissolve carbonates, HFO, manganese oxides and powellite (CaMoO4). Approximately 25% of Mo bounded to crystalline iron oxides, pyrite and OM in steps 4 and 5. In contrast to Mo, As was present in all the extractiona s steps in somewhat similar abundances: step 1 (17%), step 2 (11%), step 3 (30%), step 4 (23%) and step 5 (18%). Hydrous and crystalline iron oxides, which were dissolved in steps 3 and 4 contained the highest As concentrations. From this procedure, it became clear that compared to As, Mo is more easily released from the aquifer matrix. Pyrite and OM which were present in both aquifer matrix sediments underlying Lithia area and in Avon Park Formation (APF), were generally considered as source for Mo and As. To evaluate this statement, a total of 24 samples (including 10 samples which were already subjected to SEP analysis) were chosen from Lithia area and APF. The samples were selected based on the following four criteria: (1) high total Mo concentration, (2) high total As concentration, (3) high total sulfur concentration, and (4) good geographic representation of the study area. The results of CRS did not confirm the presence of Mo in pyrite in the Lithia area, though it was shown to exist as a minor constituent in the APF. The total organic carbon content in the residues of CRS (OCres) method was positively correlated to Mo (R2 = 0.71 and p 0.001). There was no correlation between OS and Mo. Compared to Mo, As concentration in pyrite was much higher, pointing to pyrite as a major primary source for As in the aquifer matrix sediments. There was a weak correlation between As and OCres. The results suggested that the Mo found in the aquifer matrix and groundwater was mainly sourced from OM rather than pyrite, whereas As originated mainly from pyrite as a primary source, in addition to iron oxides in the adsorbed forms. The adsorption and desorption of Mo and As by/from HFO and HA indicated that HFO was not a major sink for Mo but a significant secondary source for As. Molybdenum sorption onto HFO mainly happened by the formation of inner-sphere complexes. Arsenic(III) and As(V) sorption onto HFO resulted in inner-sphere complexes. Oxygenated water had no significant effect on the mobilization of Mo and As from the aquifer matrix in the Lithia area and APF. Powellite could be considered as a minor secondary source for Mo and As. In the alkaline pH ranges (pH ranges of the study area), the adsorption of Mo on HA was too low