The Reactivity of New Zealand Ilmenites

The dissolution of West Coast, South Island, New Zealand ilmenite in acid solutions was studied under a variety of conditions, including concentrations approaching those used industrially. The major dissolution medium considered was hydrochloric acid (1-->10 M), at temperatures of 50-->80 degrees C. The series of experiments undertaken souqht to establish the factors affecting the reactivity of the ilmenite samples. Concentrations of dissolved components of the ilmenite were followed by Atomic Absorption spectrometry and the structure and composition of the residual ilmenite was examined by X-ray powder diffraction, X-ray fluorescence, electron microprobe and scanning electron microscopy. Evidence for the rapid dissolution of an iron-rich surface phase was observed, but the dominant feature of early reaction is selective attack along zones parallel to the basal plane of the ilmenite structure. After the initial phase of rapid dissolution, reaction rate declines and all extended period of concentration/time linearity follows. This decline in rate appears to relate to polymerisation and. transport of dissolved titanium within the porous solid. The addition of phosphate and fluoride to the system, has been shown to seriously affect the properties and transport of dissolved titanium. The effects of other interfering reagents such as additional titanium and iron were also considered. The observed behaviour of these ilmenites in dissolution, was related to the pattern of natural weathering identified in other ilmenite concentrates The structure and composition of a range of these materials was examined by X-ray diffraction, Electron microprobe and Mossbauer spectroscopy

Interacting active particles and cellular automata: microscopic models of stochastic nonequilibrium systems

The broad focus of this thesis is the statistical physics of nonequilibrium systems -- systems which violate the condition of detailed balance. Detailed balance is the property that the probability fluxes between all pairs of states of a system cancel exactly, and is the defining feature of the equilibrium stationary state. Nontrivial flux cancellations -- which arise as a result of probability currents in a system's state space -- are also possible: when this happens, a system is said to be in a equilibrium stationary state. As a consequence of this increased complexity, establishing a general theory of nonequilibrium systems remains one of physics' great outstanding challenges. One route to understanding nonequilibrium systems is to consider simplified microscopic models. The benefits to this are twofold: firstly, microscopic models allow us to probe nonequilibrium processes at the most fundamental level; and secondly, by pooling together the results of various such models, we can begin to establish connections between them with a view to extracting general principles. In this thesis, we will consider two kinds of nonequilibrium system when developing microscopic models. The first kind is active systems. Active systems -- those which comprise particles that can execute motion using energy they extract from their environment -- are inherently out of equilibrium. In the presence of interactions, active particles often exhibit intriguing emergent behaviours -- such as collective motion -- which are absent in systems of passive particles. Not only, therefore, do they hold strong scientific interest, but their ubiquity in nature provides a pool of inspiration for physicists from which models may be developed and studied. The dearth in the literature of N-body microscopic models of active systems, where N ≥ 2, is a major problem if we wish to fundamentally understand how their macroscopic complexity emerges from interactions at the level of individual particles. In this thesis, we shall devote much time to the analysis of microscopic active systems in an attempt to address this. To this end, two models of interacting persistent random walkers (PRWs) will be discussed. The PRW is an active particle which moves by executing a series of linear `runs' at speed γ interspersed by random reorientation events, known as `tumbles', which occur at rate ω. Interacting PRW systems are of interest in the active-matter community as they are often inspired by and have applications to bacterial motion. The first model consists of a dilute gas of excluding PRWs in an arbitrary number of dimensions. The jamming probability -- the probability of finding a pair of adjacent PRWs mutually blocking each other -- is derived via a first-passage approach in order to investigate the nature of multiparticle clustering. This yields the surprising result of a vanishing critical density for clustering in the model's thermodynamic limit. The second PRW model generalises the exclusion interaction to an active \emph{recoil} interaction, whereby PRWs are instantaneously displaced upon contact according to an arbitrary distribution. The nonequilibrium stationary states of a one-dimensional two-PRW system featuring recoils are derived exactly using a generating-function approach, revealing a variety of rich behaviours. These include reentrant states, for which an effective attraction exists between the walkers within a finite range of tumble rates but is otherwise repulsive, as well as highly nontrivial boundary behaviours, for which a novel technique was developed in order for an exact characterisation to be established. The second kind of nonequilibrium system we shall consider is the cellular automaton (CA). A CA consists of a lattice whose sites are associated with a discrete variable. For all sites, this variable is updated in discrete time steps according to a prescribed function whose input is the site's local environment. Thus, given some initial configuration, the CA evolves through a deterministic trajectory of configurations. Engineering the update function to enforce broken detailed balance allows for the possibility of complex emergent phenomena. The CA, therefore, constitutes an alternative approach for the nonequilibrium physicist regarding the examination of emergent complexity from microscopic rules for which detailed balance does not hold. In the final chapter of this thesis, a one-dimensional CA of binary variables is modified such that two of its eight possible update rules are made stochastic. We then assess the changes this effects on the state space via simulations, revealing a pattern in the configurational structure of each sector (subspace). From this we establish a lower bound on the number of sectors of the model; we find that this lower bound is related to the Fibonacci numbers and asymptotically grows as (⁴√ϕ)ᴸ, where ϕ is the golden ratio and L is system size. This growth rate, it turns out, is substantially slower than the stochastic automaton's deterministic predecessor. Taking together the above-described models and the results we derive from them, it is hoped that this thesis constitutes a small step forward in our understanding of nonequilibrium systems

Job Life Cycle Management Libraries for CMS Workflow Management Projects

Scientific analysis and simulation requires the processing and generation of millions of data samples. These processing and generation tasks are often comprised of multiple smaller tasks divided over multiple (computing) sites. This paper discusses the Compact Muon Solenoid (CMS) workflow infrastructure, and specifically the Python based workflow library which is used for so called task lifecycle management. The CMS workflow infrastructure consists of three layers: high level specification of the various tasks based on input/output datasets, life cycle management of task instances derived from the high level specification and execution management. The workflow library is the result of a convergence of three CMS subprojects that respectively deal with scientific analysis, simulation and real time data aggregation from the experiment

Tuning attraction and repulsion between active particles through persistence

We consider the interplay between persistent motion, which is a generic property of active particles, and a recoil interaction which causes particles to jump apart on contact. The recoil interaction exemplifies an active contact interaction between particles, which is inelastic and is generated by the active nature of the constituents. It is inspired by the `shock' dynamics of certain microorganisms, such as \emph{Pyramimonas octopus}, and always generates an effective repulsion between a pair of passive particles. Highly persistent particles can be attractive or repulsive, according to the shape of the recoil distribution. We show that the repulsive case admits an unexpected transition to attraction at intermediate persistence lengths, that originates in the advective effects of persistence. This allows active particles to fundamentally change the collective effect of active interactions amongst them, by varying their persistence length

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Technologies for recovery and reuse of plant nutrients from human excreta and domestic wastewater: a protocol for a systematic map and living evidence platform

Background: Research and development on the recovery and reuse of nutrients found in human excreta and domestic wastewater has intensified over the past years, continuously producing new knowledge and technologies. However, research impact and knowledge transfer are limited. In particular, uptake and upscaling of new and innovative solutions in practice remain a key challenge. Achieving a more circular use of nutrients thus goes beyond technological innovation and will benefit from a synthesis of existing research being readily available to various stakeholders in the field. The aim of the systematic map and online evidence platform described in this protocol is threefold. First, to collate and summarise scientific research on technologies that facilitate the recovery and reuse of plant nutrients and organic matter found in human excreta and domestic and municipal wastewater. Second, to present this evidence in a way that can be easily navigated by stakeholders. Third, to report on new relevant research evidence to stakeholders as it becomes available.Methods: Firstly, we will produce a baseline systematic map, which will consist of an extension of two previous related syntheses. In a next stage, with help of machine learning and other automation technologies, the baseline systematic map will be transformed into 'living mode' that allows for a continually updated evidence platform. The baseline systematic map searches will be performed in 4 bibliographic sources and Google Scholar. All searches will be performed in English. Coding and meta-data extraction will include bibliographic information, locations as well as the recovery and reuse pathways. The living mode will mostly rely on automation technologies in EPPI-Reviewer and the Microsoft Academic database. The new records will be automatically identified and ranked in terms of eligibility. Records above a certain 'cut-off' threshold will be manually screened for eligibility. The threshold will be devised based on the empirically informed machine learning model. The evidence from the baseline systematic map and living mode will be embedded in an online evidence platform that in an interactive manner allows stakeholders to visualise and explore the systematic map findings, including knowledge gaps and clusters

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia

Transport of DNA within cohesin involves clamping on top of engaged heads by Scc2 and entrapment within the ring by Scc3.

In addition to extruding DNA loops, cohesin entraps within its SMC-kleisin ring (S-K) individual DNAs during G1 and sister DNAs during S-phase. All three activities require related hook-shaped proteins called Scc2 and Scc3. Using thiol-specific crosslinking we provide rigorous proof of entrapment activity in vitro. Scc2 alone promotes entrapment of DNAs in the E-S and E-K compartments, between ATP-bound engaged heads and the SMC hinge and associated kleisin, respectively. This does not require ATP hydrolysis nor is it accompanied by entrapment within S-K rings, which is a slower process requiring Scc3. Cryo-EM reveals that DNAs transported into E-S/E-K compartments are 'clamped' in a sub-compartment created by Scc2's association with engaged heads whose coiled coils are folded around their elbow. We suggest that clamping may be a recurrent feature of cohesin complexes active in loop extrusion and that this conformation precedes the S-K entrapment required for sister chromatid cohesion

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good