Editorial: Research as practice: on critical methodologies

Isabelle Stengers, perhaps unwittingly, perhaps knowingly, echoes a theme of the work of American philosopher Stanley Cavell (1995, p. 136) when she invites in the first edition of the journal Subjectivity, her readers to join her in slowing down, in hesitating, pausing, taking a breath in the face of our own endeavours to ‘produce subjectivity’ (Stengers, 2008, p. 49). Cavell’s gesture of hesitation is similarly evocative and provocative. Where Stengers pushes for an approach which betrays or reveals rather than denounces, Cavell suggests that in the face of apparently constitutive philosophical oppositions, in stead of seeking to decide we should seek to dismantle. Betrayal rather than denunciation; revelation rather than condemnation; dismantling rather than deciding. Alluring and seductive ideas but the question is begged: where is the critical edge? This volume grapples with this question. It hesitates in the face of the complex relations between theory, research methods and practice, and the persons and places, or milieus, they are embedded in. It represents an attempt to revive the question as to what it means to do psychology critically, or for that matter, to practice critical theory

Rapid gravity filtration operational performance assessment and diagnosis for preventative maintenance from on-line data

Rapid gravity filters, the final particulate barrier in many water treatment systems, are typically monitored using on-line turbidity, flow and head loss instrumentation. Current metrics for assessing filtration performance from on-line turbidity data were critically assessed and observed not to effectively and consistently summarise the important properties of a turbidity distribution and the associated water quality risk. In the absence of a consistent risk function for turbidity in treated water, using on-line turbidity as an indicative rather than a quantitative variable appears to be more practical. Best practice suggests that filtered water turbidity should be maintained below 0.1 NTU, at higher turbidity we can be less confident of an effective particle and pathogen barrier. Based on this simple distinction filtration performance has been described in terms of reliability and resilience by characterising the likelihood, frequency and duration of turbidity spikes greater than 0.1 NTU. This view of filtration performance is then used to frame operational diagnosis of unsatisfactory performance in terms of a machine learning classification problem. Through calculation of operationally relevant predictor variables and application of the Classification and Regression Tree (CART) algorithm the conditions associated with the greatest risk of poor filtration performance can be effectively modelled and communicated in operational terms. This provides a method for an evidence based decision support which can be used to efficiently manage individual pathogen barriers in a multi-barrier system

Toward gas-phase controlled mass transfer in micro-porous membrane contactors for recovery and concentration of dissolved methane in the gas phase

A micro-porous hollow fibre membrane contactor (HFMC) operated in sweep-gas mode has been studied to enable the recovery of dissolved methane from water in concentrated form. At high sweep-gas flow rates, up to 97% dissolved methane removal efficiency is achievable which is sufficient to achieve carbon neutrality (around 88%). An increase in methane composition of the recovered sweep-gas was achievable through two primary mechanisms: (i) an increase in liquid velocity which improved dissolved methane mass transfer into the gas phase; and (ii) a reduction in gas flow which lowered dilution from the receiving gas phase. It was posited that further refinement of the methane content was provided through counter-diffusion of the nitrogen sweep-gas into the liquid phase. Within the boundary conditions studied, the methane composition of the recovered gas phase exceeded the threshold for use in micro-turbines for electricity production. However, reducing the gas-to-liquid ratio to enhance gas phase methane purity introduced gas-phase controlled mass transfer which constrained removal efficiency. Whilst this reduction in removal efficiency can be compensated for by extending path length (i.e. more than one module in series), it is suggested that the gas-phase controlled conditions encountered were also a product of poor shell-side dispersion rather than an approach toward the limiting theoretical gas-to-liquid ratio. This implies that further optimisation can be ascertained through improved membrane contactor design. Importantly, this study demonstrates that micro-porous hollow fibre membrane contactors provide a compact process for recovery of dissolved methane in sufficient concentration for re-use

Quantifying the loss of methane through secondary gas mass transport (or 'slip') from a micro-porous membrane contactor applied to biogas upgrading

Secondary gas transport during the separation of a binary gas with a micro-porous hollow fibre membrane contactor (HMFC) has been studied for biogas upgrading. In this application, the loss or ‘slip' of the secondary gas (methane) during separation is a known concern, specifically since methane possesses the intrinsic calorific value. Deionised (DI) water was initially used as the physical solvent. Under these conditions, carbon dioxide (CO2) and methane (CH4) absorption were dependent upon liquid velocity (VL). Whilst the highest CO2 flux was recorded at high VL, selectivity towards CO2 declined due to low residence times and a diminished gas-side partial pressure, and resulted in slip of approximately 5.2% of the inlet methane. Sodium hydroxide was subsequently used as a comparative chemical absorption solvent. Under these conditions, CO2 mass transfer increased by increasing gas velocity (VG) which is attributed to the excess of reactive hydroxide ions present in the solvent, and the fast conversion of dissolved CO2 to carbonate species reinitiating the concentration gradient at the gas-liquid interface. At high gas velocities, CH4 slip was reduced to 0.1% under chemical conditions. Methane slip is therefore dependent upon whether the process is gas phase or liquid phase controlled, since methane mass transport can be adequately described by Henry's law within both physical and chemical solvents. The addition of an electrolyte was found to further retard CH4 absorption via the salting out effect. However, their applicability to physical solvents is limited since electrolytic concentration similarly impinges upon the solvents' capacity for CO2. This study illustrates the significance of secondary gas mass transport, and furthermore demonstrates that gas-phase controlled systems are recommended where greater selectivity is required

Biogas upgrading by chemical absorption using ammonia rich absorbents derived from wastewater

The use of ammonia (NH3) rich wastewaters as an ecological chemical absorption solvent for the selective extraction of carbon dioxide (CO2) during biogas upgrading to ‘biomethane’ has been studied. Aqueous ammonia absorbents of up to 10,000 gNH3 m−3 demonstrated CO2 absorption rates higher than recorded in the literature for packed columns using 20,000–80,000 g NH3 m−3 which can be ascribed to the process intensification provided by the hollow fibre membrane contactor used in this study to support absorption. Centrifuge return liquors (2325 g m−3 ionised ammonium, NH4+) and a regenerant (477 gNH4+ m−3) produced from a cationic ion exchanger used to harvest NH4+ from crude wastewater were also tested. Carbon dioxide fluxes measured for both wastewaters compared reasonably with analogue ammonia absorption solvents of equivalent NH3 concentration. Importantly, this demonstrates that ammonia rich wastewaters can facilitate chemically enhanced CO2 separation which eliminates the need for costly exogenic chemicals or complex chemical handling which are critical barriers to implementation of chemical absorption. When testing NH3 analogues, the potential to recover the reaction product ammonium bicarbonate (NH4HCO3) in crystalline form was also illustrated. This is significant as it suggests a new pathway for ammonia separation which avoids biological nitrification and produces ammonia stabilised into a commercially viable fertiliser (NH4HCO3). However, in real ammonia rich wastewaters, sodium bicarbonate and calcium carbonate were preferentially formed over NH4HCO3 although it is proposed that NH4HCO3 can be preferentially formed by manipulating both ion exchange and absorbent chemistry

Therapeutic Discipline? Reflections on the Penetration of Sites of Control by Therapeutic Discourse

This article addresses the way in which therapeutic practice in an English prison creates conditions whereby both prisoners and prison officers are caught up in networks and relationships of power that contribute to the constitution of particular subjects. The development of therapeutic practice, in relation to prisons and probation, is described and contextualised. Subsequently, the practices of group therapy in operation at Grendon prison - a rather unique institution built on principles of therapeutic community – are analysed with a focus on five ”practices of moulding,” namely, naming, confession, assessment and surveillance, tolerance and participation. The argument that psychotherapy, under conditions of imprisonment, is a form of repression or social control is discussed and dismissed as too simple a model to account for the relations of power and constitutive practices that effect all participants, not only prisoners. Members of staff, as well as prisoners, are shown to be caught up in the disciplinary web. Discipline, as opposed to control, is advocated as a more appropriate concept for understanding therapeutic practices in prison. The work of Thomas Mathiesen, on the concept of synoptic power, is introduced to help illustrate these dynamics. The article represents a shift in my own thinking, from scepticism to a pragmatic idealist position, that creates space for institutions like Grendon to be imagined as potential least worst options for people convicted of offences and obliged to serve “time”. It is my hope, argued for in the article, that Grendon can be conceived of as a “visionary space” with emancipatory potential

Entomological Technique as Referring to the Life History of Insects

According to the statement of Kellogg in American Insects, man\u27s real competitors are not the larger creatures that inhabit the Earth with us. These are relatively few in number and easily controlled; but the tiny creatures - the insects and insect-like creatures are the ones that present a real problem to us. They conquer us many times because they are so prolific and so numerous and because they are so small they often go unnoticed. Our Nation has realized the problem and has appropriated millions of dollars annually for the control of insects. This expenditure, however, is not sufficient and the general public should have more knowledge of insects as well as the other branches of nature study. To a better understanding of insect life and to carry on a more efficient warfare against our insect pests, more trained instructors are needed in our schools, colleges, and universities. Much research and writing has been done in entomology, but there is need of some works of compilation or condensation of large volumes into workable form so that the teacher and student may grasp it quickly and easily. In the following pages I have collected the best information available upon the subjects treated and put it into readable form. It is, however, a mere beginning, and it is presented with the hope that others will carry this work to completion

Controlling shell-side crystal nucleation in a gas-liquid membrane contactor for simultaneous ammonium bicarbonate recovery and biogas upgrading

A gas–liquid hollow fibre membrane contactor (HFMC) process has been introduced for carbon dioxide (CO2) separation from biogas where aqueous ammonia (NH3) is used to chemically enhance CO2 absorption and initiate heterogeneous nucleation of the reaction product ammonium bicarbonate at the membrane–solvent interface. Aqueous ammonia absorbents (2–7 M) were initially used in single pass for CO2 separation from a synthetic biogas where nucleation of ammonium bicarbonate crystals was observed at the perimeter of the micropores. Recirculation of the aqueous ammonia absorbent encouraged the growth of ammonium bicarbonate crystals on the shell-side of the membrane that measured several microns in diameter. However, at high aqueous NH3 concentrations (3–7 M), lumen side crystallisation occurred and obstructed gas flow through the lumen of the HFMC. The suggested mechanism for lumen-side crystallisation was absorbent breakthrough into the lumen due to pore wetting which was promoted by low absorbent surface tension at high NH3 concentration. Preferential shell-side nucleation can therefore be promoted by (1) raising surface tension of the absorbent and (2) selection of a membrane with a more regulated pore shape than the PTFE membrane used (d/L 0.065) as both actions can diminish solvent ingress into the pore. This was evidenced using 2 M NH3 absorbent where shell-side crystallisation was evidenced without the onset of lumen side crystallisation. Raising surface tension through the inclusion of salt into the chemical absorbent also promoted greater CO2 flux stability. Importantly, this study demonstrates that chemically enhanced HFMC are an attractive prospect for gas–liquid separation applications where reaction product recovery offers further economic value