Статті в журналах з теми "Population Balance Equation. Soft Matter"

In this study, the propagation of a fundamental plane mode in a bifurcated waveguide structure with soft–hard boundaries is analyzed by using the Helmholtz equation. The explicit solution is given to this bifurcated spaced waveguide problem by means of matching the potential across the boundary of continuity. Amplitudes of the reflected field in all those regions have been evaluated, and the energy balance has been derived. We have observed the reflection of the acoustic wave against the wavenumber and shown its variation with the duct width. Convergence of the problem has been shown graphically. In our analysis, we notice that the reflected amplitude decreases as the duct spacing increases; as a result, the acoustic energy will increase as the duct spacing increases. It is expected that our analysis could be helpful to give better understanding of wave reflection in an exhaust duct system. We then reduce the linear acoustic wave equation to the Kadomtsev–Petviashvili (KP) equation. Multiple-periodic wave interaction solutions of the KP nonlinear wave equation are investigated, and the energy transfer mechanism between the primary and higher harmonics is explained, which, to the best of our knowledge, is overlooked.

In recent years, ablative plasma generated by capillary discharge attracted considerable attention because of its possible applications in electrothermal launchers, laser-driven particle accelerators, thin-film deposition and soft X-ray lasers, etc. An electrical discharge through a capillary insulator heats the capillary plasma that provides further evaporation of the capillary wall and electrode. The created plasma is confined by the capillary wall, electrode material and flow in a specified chamber through a hollow electrode. The mass flux leaving the capillary in axial motion is replenished by a radial inward flow of matter. Thus the radial component of the mass flux plays a principal role in the mass and energy balance. In this paper, we present a theoretical model for a time-dependent magneto-hydrodynamical simulation to calculate the dynamic evolution of plasma flow and transportation in two-dimensional configurations combined with turbulent effect. The thermodynamic and transport properties are characterized by a model that describes the plasma composition, equation of state, internal energy, viscosity and thermal and electrical conductivity for a partially ionized multi-component plasma in the weakly non-ideal region, similar to that which exists in the ablation-controlled arcs. Our model results show that some of the well-known experimental features of this kind of discharge are confirmed, particularly the radial mass and energy transportation.

In this contribution, crystallization was performed to assess the kinetics of nucleation and crystal growth of L-lactide. In most common solvents, this compound shows very high solubility even at low temperatures, which could be challenging for crystallization process design. In the first part of this paper, the anti-solvent effects of n-hexane on solutions of L-lactide in tetrahydrofuran (THF) were investigated through studying the influence of solvent compositions on the solubility. Thanks to these effects, the solubility of the interested compound can be adjusted to desired degrees of supersaturation by adding suitable amounts of the anti-solvent. In the second part, a solvent composition at a mass ratio of 45/55 (n-hexane/THF) was chosen, and an isothermal seeded crystallization process was implemented. The evolution of the particle sizes and changes in the solute concentration profile of this process were monitored. Based on the obtained data, a widely used model, i.e., the population balance equation (PBE), was then utilized to model the crystal size distribution (CSD). Reasonable assumptions were made to reduce the mathematical complexity of the PBE. In the simplified model, only crystal growth and secondary nucleation were considered for model formulation, with assumptions of the size-independent growth rate and negligible size of nuclei. The kinetic parameters were estimated by using the seed and final-time crystal density functions in combination with variations in the concentration of the mother liquor. Indeed, the numerical solution for the one-dimensional problem of the L-lactide crystallization based on the estimated parameters gained a relatively good agreement with the determined CSD. Furthermore, the obtained model also correlated well with the variations in the solute concentration of the mother liquor. In short, this simple approach can be used for predicting the productivity and CSD of the L-lactide crystallization.

We investigate the conditions under which ‘high-frequency’ electron acoustic–Langmuir solitons can be constructed in a plasma consisting of protons and two electron populations: one ‘cold’ and the other ‘hot’. Conservation of total momentum can be cast as a structure equation either for the ‘cold’ or ‘hot’ electron flow speed in a stationary wave using the Bernoulli energy equations for each species. The linearized version of the governing equations gives the dispersion equation for the stationary waves of the system, from which follows the necessary – but not sufficient – conditions for the existence of soliton structures; namely that the wave speed must be less than the acoustic speed of the ‘hot’ electron component and greater than the low-frequency compound acoustic speed of the two electron populations. In this wave speed regime linear waves are ‘evanescent’, giving rise to the exponential growth or decay, which readily can give rise to non-linear effects that may balance dispersion and allow soliton formation. In general the ‘hot’ component must be more abundant than the ‘cold’ one and the wave is characterized by a compression of the ‘cold’ component and an expansion in the ‘hot’ component necessitating a potential dip. Both components are driven towards their sonic points; the ‘cold’ from above and the ‘hot’ from below. It is this transonic feature which limits the amplitude of the soliton. If the ‘hot’ component is not sufficiently abundant the window for soliton formation shrinks to a narrow speed regime which is quasi-transonic relative to the ‘hot’ electron acoustic speed, and it is shown that smooth solitons cannot be constructed. In the special case of a very cold electron population (i.e. ‘highly supersonic’) and the other population being very hot (i.e. ‘highly subsonic’) with adiabatic index 2, the structure equation simplifies and can be integrated in terms of elementary transcendental functions that provide the fully non-linear counterpart to the weakly non-linear sech$^{2}$-type solitons. In this case the limiting soliton is comprised of an infinite compression in the cold component, a weak rarefaction in the ‘hot’ electrons and a modest potential dip.

The relationship between agricultural extension and farmer productivity has been widely discussed; agricultural extension directly or indirectly affects farmer productivity. In this study, the researchers attempted to elaborate on this matter by looking at it from the rural wing based on the human resource and human capital theory. This study uses a quantitative explanatory approach. The analytical tool used is Structural Equation Modeling (SEM) as a fundamental data analysis using AMOS software. The population in this study were all agricultural extensions in South Sulawesi and West Sulawesi. The sample was taken using the accidental sampling technique; it included only the completed questionnaire in the data analysis. Until the time limit, only 122 agricultural extension people filled out the questionnaire and were declared complete. Research shows that rural extension has a significant positive effect on soft-skill competence and not substantial on farmer productivity. Furthermore, soft-skill competence significantly affects farmer productivity and is a good mediator in increasing farmer productivity. The results show that it could improve farmers' productivity, not because of direct extension but because the farmers' soft competence increased due to interventions from the quality of agricultural extension workers. Therefore, good quality agricultural extension agents will encourage the rural farmers' ability to solve problems. Make systematic planning and communication skills that will help them build relationships with colleagues and stakeholders, improve ethics, discipline, increase their skills and experience.

With growing interest in the simulation of compressible flows using the lattice Boltzmann (LB) method, a number of different approaches have been developed. These methods can be classified as pertaining to one of two major categories: (i) solvers relying on high-order stencils recovering the Navier–Stokes–Fourier equations, and (ii) approaches relying on classical first-neighbour stencils for the compressible Navier–Stokes equations coupled to an additional (LB-based or classical) solver for the energy balance equation. In most cases, the latter relies on a thermal Hermite expansion of the continuous equilibrium distribution function (EDF) to allow for compressibility. Even though recovering the correct equation of state at the Euler level, it has been observed that deviations of local flow temperature from the reference can result in instabilities and/or over-dissipation. The aim of the present study is to evaluate the stability domain of different EDFs, different collision models, with and without the correction terms for the third-order moments. The study is first based on a linear von Neumann analysis. The correction term for the space- and time-discretized equations is derived via a Chapman–Enskog analysis and further corroborated through spectral dispersion–dissipation curves. Finally, a number of numerical simulations are performed to illustrate the proposed theoretical study. This article is part of the theme issue ‘Fluid dynamics, soft matter and complex systems: recent results and new methods’.

The steady-state migration of ions, driven by a uniform electric field against full-stop collisions, is investigated in some detail. The required phase-space distribution is obtained very easily from Boltzmann's equation together with explicit recognition of energy conservation and population balance for the stagnant ion pool. We go on to decompose this aggregate solution into ion tiers classified by the number of background impacts previously endured. Such a decomposition permits us to detect the presence of Poisson statistics (as to collision number) lurking within the composite, thermalized Maxwellian, and likewise also a multiple-scattering hierarchy having the maiden, first-flight distribution for its natural kernel. Scattering-sequence accounting, in particular, allows a quantitative (even though unwieldy) distinction to be made between ions of varying residence times. A model of this sort is motivated by the technique of ion implantation through sample immersion within a plasma at higher electric potential. Numerical consequences of the solution obtained here reveal that both ion density and average kinetic energy relax to their terminal values within just a few mean free-path lengths. Such modest scaling of plasma-sheath extent evidently carries a beneficial implication for the technological ease with which surface properties (such as metal corrosion resistance and hardness) remain open to improvement via ion bombardment.

While substantial effort has been expended on molecular techniques in an attempt to break through the apparent ceiling for sucrose content (SC) in sugarcane stalks, molecular processes and genetics limiting sucrose accumulation remain unclear. Our own studies indicate that limiting expansive growth with water stress will enhance sucrose accumulation in both low- and high-sucrose clones. Sucrose accumulation was largely explained (72%) by an equation with terms for photosynthesis, plant extension rate (PER), and plant number. New research was conducted to determine if this simple model stands when using temperature rather than water stress to perturb the source–sink balance. We also applied a thinning treatment to test the proposal implicit in this equation that SC will increase if competition between plants for photo-assimilate is reduced. Four clones from a segregating population representing extremes in SC were planted in pots and subjected to warm and cool temperature regimes in a glasshouse facility. A thinning treatment was imposed on half the pots by removing all but 6 shoots per pot. Temperature as a means of reducing sink strength seemed initially to be more successful than water regime because PER was 43% lower in the cool than in the hot regime while photosynthesis was only 14% less. PER was a good indicator of dry matter allocation to expansive growth, limited by water stress but not by temperature, because stalks tended to thicken in low temperature. Thinning had little effect on any of the attributes measured. Nevertheless the clonal variation in plant numbers and the response of PER to temperature helped to explain at least 69% of the variation in sucrose accumulation observed in this experiment. Thus the earlier model for sucrose accumulation appeared to be valid for the effect on sucrose accumulation of both temperature and water stress on the source–sink balance. The next step is to include internodes in models of assimilate partitioning to help understand the limiting steps in sucrose accumulation from the basics of source–sink dynamics.

ObjectivesThe objective was to develop and validate a risk model for the likelihood of extensive white matter lesions (extWML) to inform clinicians on whether to proceed with or forgo diagnostic MRI.DesignPopulation-based cohort study and multivariable prediction model.SettingTwo representative samples from France.ParticipantsPersons aged 60–80 years without dementia or stroke. Derivation sample n=1714; validation sample n=789.Primary and secondary outcome measuresVolume of extWML (log cm3) was obtained from T2-weighted images in a 1.5 T scanner. 20 candidate risk factors for extWML were evaluated with the C-statistic. Secondary outcomes in validation included incident stroke over 12 years follow-up.ResultsThe multivariable prediction model included six clinical risk factors (C-statistic=0.61). A cut-off of 7 points on the multivariable prediction model yielded the optimum balance in sensitivity 63.7% and specificity 54.0% and the negative predictive value was high (81.8%), but the positive predictive value was low (31.5%). In further validation, incident stroke risk was associated with continuous scores on the multivariable prediction model (HR 1.02; 95% CI 1.01 to 1.04, P=0.02) and dichotomised scores from the multivariable prediction model (HR 1.28; 95% CI 1.02 to 1.60, P=0.03).ConclusionsA simple clinical risk equation for WML constituted by six variables can inform decisions whether to proceed with or forgo brain MRI. The high-negative predictive value demonstrates potential to reduce unnecessary MRI in the population aged 60–80 years.

Context. The origin of Galactic cosmic rays remains a matter of debate, but supernova remnants are commonly considered to be the main place where high-energy cosmic rays are accelerated. Nevertheless, current models predict cosmic-ray spectra that do not match observations and the efficiency of the acceleration mechanism is still undetermined. On the other hand, the contribution of other kinds of sources to the Galactic cosmic-ray population is still unclear, and merits investigation. Aims. In this work we explore a novel mechanism through which microquasars might produce cosmic rays. In this scenario, microquasar jets generate relativistic neutrons, which escape and decay outside the system; protons and electrons, created when these neutrons decay, escape to the interstellar medium as cosmic rays. Methods. We introduce the relativistic neutron component through a coupling term in the transport equation that governs the jet proton population. We compute the escape rate and decay distribution of these neutrons, and follow the propagation of the decay products until they escape the system and become cosmic rays. We then compute the spectra of these cosmic rays. Results. Neutrons can drain only a small fraction of the jet power as cosmic rays. The most promising scenarios arise in extremely luminous systems (Ljet ∼ 1040 erg s−1), in which the fraction of jet power deposited in cosmic rays can reach ∼0.001. Slow jets (Γ ≲ 2, where Γ is the bulk Lorentz factor) favour neutron production. The resulting cosmic-ray spectrum is similar for protons and electrons, which share the power in the ratio given by neutron decay. The spectrum peaks at roughly half the minimum energy of the relativistic protons in the jet; it is soft (spectral index ∼3) above this energy, and almost flat below. Conclusions. The proposed mechanism produces more energetic cosmic rays from microquasars than those presented by previous works in which the particles escape through the jet terminal shock. Values of spectral index steeper than 2 are possible for cosmic rays in our model and these indeed agree with those required to explain the spectral signatures of Galactic cosmic rays, although only the most extreme microquasars provide power comparable to that of a typical supernova remnant. The mechanism explored in this work may provide stronger and softer cosmic-ray sources in the early Universe, and therefore contribute to the heating and reionisation of the intergalactic medium.

The objective of the present study is to investigate turbulence–coagulation interaction via direct numerical simulation (DNS) coupled with the population balance equation (PBE). Coagulation is an important process in several environmental and engineering applications involving turbulent flow, including soot formation, gas-phase synthesis of nanoparticles and atmospheric processes, but its interaction with turbulence is not yet fully understood. Particle dynamics can be described by the PBE, whose Reynolds decomposition leads to unclosed terms involving correlations of number density fluctuations. In this work, we employ a discretisation (sectional) method for the solution of the PBE, which is free of a priori assumptions regarding the particle size distribution (PSD), and couple it with a DNS for the flow field in order to study the behaviour and significance of the unknown correlations. At present, it is not feasible to resolve the Batchelor scales that result from diffusion at high Schmidt number, hence a unity Schmidt number is employed. The investigation is conducted on a three-dimensional planar jet laden with monodisperse nanoparticles, and coagulation in the free-molecule regime is considered. The correlations due to turbulent fluctuations of the particle number density are calculated at several points in the domain and found to be positive in most cases, except close to the jet break-up. The transport equation for the moments of the PSD is also studied, and it is found that the correlations make a considerable contribution to the time-averaged coagulation source term, up to $20\,\%$ on the jet centreline and $40\,\%$ close to the edges.

Understanding the size of oil droplets released from a jet in crossflow is crucial for estimating the trajectory of hydrocarbons and the rates of oil biodegradation/dissolution in the water column. We present experimental results of an oil jet with a jet-to-crossflow velocity ratio of 9.3. The oil was released from a vertical pipe 25 mm in diameter with a Reynolds number of 25 000. We measured the size of oil droplets near the top and bottom boundaries of the plume using shadowgraph cameras and we also filmed the whole plume. In parallel, we developed a multifluid large eddy simulation model to simulate the plume and coupled it with our VDROP population balance model to compute the local droplet size. We accounted for the slip velocity of oil droplets in the momentum equation and in the volume fraction equation of oil through the local, mass-weighted average droplet rise velocity. The top and bottom boundaries of the plume were captured well in the simulation. Larger droplets shaped the upper boundary of the plume, and the mean droplet size increased with elevation across the plume, most likely due to the individual rise velocity of droplets. At the same elevation across the plume, the droplet size was smaller at the centre axis as compared with the side boundaries of the plume due to the formation of the counter-rotating vortex pair, which induced upward velocity at the centre axis and downward velocity near the sides of the plume.

ABSTRACTSilica and titania particles are readily synthesized by the hydrolysis of alkoxides in various alcohols. The present research studies experimentally and models the chemistry and growth kinetics of silica and titania particles in low molecular weight alcohols (methanol, ethanol, 1-propanol, 1-butanol). The theoretical model is based on solving the hydrolysis and condensation kinetic expressions and applying the method of moments to expedite the solution of the governing population balance equation.

ABSTRACTThe simulation of curvature driven growth in grain boundary systems is becoming an important tool in understanding the behavior of microstructure evolution and there is much distinguished work in this subject. Here we address the mesoscale simulation of large systems of grain boundaries subject to the Mullins equation of curvature driven growth with the Herring force balance equation imposed at triple junctions. We discuss several novel features of our approach which we anticipate will render it a flexible, scalable, and robust tool to aid in microstructural prediction. What is the result of the simulation? We discuss what such a simulation is capable of predicting, taking as a prototype the histogram of relative area population as it changes through the simulation. We do not use this data to seek the best distribution, like Hillert, Rayleigh, or lognormal. Instead we treat the set of distributions as the solution of an inverse problem for a time varying function and determine the equation they satisfy. This results in a coarse graining of the complex simulation to simpler system governed by a Fokker-Planck Equation. Even so, fundamental questions concerning the predictability of simulations of large metastable systems arise from these considerations.

Using theoretical and computational tools for predicting thermophysical properties of fluid systems and the soft matter has always been of interest to the physical, chemical, and engineering sciences. And certainly, the ultimate goal is to be able to compute these macroscopic properties from first principle calculations beginning with the very atomic constitution of matter. In this work, Mie potential parameters were obtained through dimer interaction energy curves derived from ab initio calculations to represent methane and methane-substituted molecules in a spherical 1-site coarse-grained model. Bottom-up-based Mie potential parameters of this work were compared to top-down-based ones from the statistical associating fluid theory (SAFT) models for the calculation of thermodynamic properties and critical point by molecular dynamics simulations and SAFT-VR Mie equation of state. Results demonstrated that bottom-up-based Mie potential parameters when averaging the Mie potential parameters of a representative population of conformers provide values close to the top-down-based ones from SAFT models and predict well properties of tetrahedral molecules. This shows the level of consistency embedded in the SAFT-VR Mie family of models and confers a status of a purely predictive equation of state for SAFT-VR Mie when a reasonable model is considered to represent a molecule of interest.

ABSTRACTThe formation of submicron crystals of boron carbide (B4C) by rapid carbothermal reduction of intimately mixed carbon-boron oxide precursor powders in an aerosol flow reactor at temperatures above the boiling point of boron oxide is investigated. The employed high heating rates (105 K/s) of the process force release of gaseous boron oxide and suboxides and rupture of the precursor particles resulting in formation of boron carbide molecular clusters that grow to macroscopic particles by coagulation. Consequently, the formation and growth of B4C particles is described by simultaneous interparticle collision and coalescence using a two-dimensional distribution model that traces the evolution of both size and shape characteristics of the particles through their volume and surface area. Here, in addition to the coagulation term, the governing population balance equation includes a coalescence contribution based on B4C sintering law. The predicted evolution of the two-dimensional particle size distribution leads to a direct characterization of morphology as well as the average size and polydispersity of the powders. Furthermore, model predictions of the volume and surface area of boron carbide particles can be directly compared with experimental data of B4C specific surface area and grain size.

AbstractThe population balance methodology is described and applied to the transport and capture of polydispersed colloids in packed columns. The transient model includes particle growth, capture, convective transport, and dispersion. We also follow the dynamic accumulation of captured colloids on the solids. The multidimensional parabolic partial differential equation was solved by a recently enhanced method of characteristics technique. This computational technique minimized numerical dispersion and is computationally very fast. The FORTRAN 77 code ran on a VAX-780 in less than a minute and also runs on an IBM-AT using the Professional FORTRAN compiler. The code was extensively tested against various simplified cases and against analytical models.The packed column experiments by Saltelli et al. were re-analyzed incorporating the experimentally reported size distribution of the colloid feed material. Colloid capture was modeled using a linear size dependent filtration function. The effects of a colloid size dependent filtration factor and various initial colloid size distributions on colloid migration and capture were investigated. Also, we followed the changing colloid size distribution as a function of position in the column.Some simple arguments are made to assess the likelihood of colloid migration at a potential NTS Yucca Mountain waste disposal site.

The objective of this work is to investigate the interaction of turbulence with the nonlinear processes of particle nucleation and growth that occur in reaction crystallisation, also known as precipitation. A validated methodology for coupling the population balance equation with direct numerical simulation of turbulent flows is employed for simulating an experiment conducted by Schwarzer et al. (Chem. Engng Sci., vol. 61, no. 1, 2006, pp. 167–181), where barium sulphate nanoparticles are formed by mixing and reaction of barium chloride and sulphate acid in a T-mixer, with the spatial resolution resolved down to the Kolmogorov scale. A unity Schmidt number is assumed, since at present it is not possible to resolve the Batchelor scale for realistic Schmidt numbers (order of 1000 or more). The probability density function, filtered averages and spatial distribution of time and length scales are all examined in order to shed light on the interplay of turbulence and precipitation. Separate Damköhler numbers are defined for nucleation and growth and both are found to be close to unity, indicating that the process is neither mixing nor kinetics controlled. The nucleation length scales are also evaluated and compared with the Kolmogorov scale to show the importance of resolving nucleation bursts. In addition, zones of different rate-determining mechanisms are identified. The ultimate aim of precipitation is to obtain control over the product particle size distribution, and the present study elucidates the synergistic or competing roles of mixing, nucleation and growth on the process outcome and discusses the implications for modelling.

Introduction Gore Vidal, the famous writer and literary critic, was recently buried next to his long-term partner, Howard Austen. The couple, who met in the 1950s, had lived together happily for decades. They were in many ways the kind of same-sex couple frequently valorised in contemporary gay marriage campaigns. Vidal and Austen, however, could not serve as emblematic figures for this campaign, and not only because the two men had no interest in marriage. Vidal, who reportedly had over a hundred lovers, both male and female, once attributed the longevity of their relationship to its platonic nature; both men continued to sleep with other people, and they reportedly stopped having sex with each other after they moved in together (Vidal, Palimpsest, 131–32). A relationship that decoupled monogamy, romance, companionship, and sexuality, and reconnected them in a way that challenged the accepted truths of institutionalised marriage, stands as an implicit questioning of the way in which gay marriage campaigns construct the possibilities for life, love, and sex. It is this questioning that we draw out in this article. In his writing, Vidal also offers a perspective that challenges the assumptions and certainties of contemporary politics around gay marriage. In 1981, he wrote “Some Jews and the Gays” in response to an article entitled “The Boys on the Beach” by conservative Jewish writer Midge Decter. Vidal’s riposte to Decter’s depiction of the snide superiority of the “boys” who disturbed her beachside family holidays highlighted the lack of solidarity conservative members of the Jewish community displayed towards another persecuted minority. From Vidal’s perspective, this was because Decter could not conceive of gay identity as anything other than pathological: Since homosexualists choose to be the way they are out of idle hatefulness, it has been a mistake to allow them to come out of the closet to the extent that they have, but now that they are out (which most are not), they will have no choice but to face up to their essential hatefulness and abnormality and so be driven to kill themselves with promiscuity, drugs, S-M, and suicide. (Vidal, Some Gays) In response, Vidal made a strong case for solidarity between Jews, African-Americans, and what he termed “homosexualists” (or “same-sexers”). More importantly for our argument, he also contested Decter’s depiction of the typical homosexual: To begin to get at the truth about homosexualists, one must realise that the majority of those millions of Americans who prefer same-sex to other-sex are obliged, sometimes willingly and happily but often not, to marry and have children and to conform to the guidelines set down by the heterosexual dictatorship. (Vidal, Some Gays) According to Vidal, Decter’s article applied only to a relatively privileged section of homosexualists who were able to be “self-ghettoized”, and who, despite Decter’s paranoid fantasies, lived lives perfectly “indifferent to the world of the other-sexers.” In the thirty years since the publication of “Some Jews and the Gays” much has clearly changed. It is unlikely that even a conservative publication would publish an article that depicts all homosexualists as marked by idle hatefulness. However, Decter’s self-hating homosexualist continues to haunt contemporary debates about same-sex marriage, albeit in sublimated form. Critiques of gay marriage campaigns, which are becoming increasingly difficult to ignore, often focus on the politics of inclusion and exclusion, whether on the terrain of gender (non)conformity (Spade), or the campaigns’ implicit and racialised assumption of a white, middle-class homosexual couple as the subject of their efforts (Riggs; Farrow). While our article is indebted to these critiques, our argument is focused more specifically on the unintended effect of the Australian debate about same-sex marriage, namely the (re)creation of the married couple’s other in the form of the adolescent, promiscuous, and unhappy homosexual. It is here that we find the source of our title, also chosen in tribute to Vidal, who in his life and writing disrupts this dichotomy. We argue that the construction of the respectable white middle-class same-sexer who sits at the centre of gay marriage discourse relies on a contemporary manifestation of the self-hating homosexualist – the sexually irresponsible queer constructed in contrast to the responsible gay. The first half of this article traces this construction. In the second section, we argue that this process cannot be divorced from the ways that advocates of same-sex marriage depict the institution of marriage. While critics such as Judith Butler have attempted to separate arguments against homophobic discrimination from the need to advocate for marriage, we argue that the two are intrinsically linked in marriage equality campaigns. These campaigns seek to erase both the explicit critique of marriage found in Vidal’s article and the implicit possibility of living otherwise found in his life. Instead of a heterosexual dictatorship that can be successfully avoided, marriage is proclaimed to be not only benign but the only institution capable of saving self-hating queers from misery by turning them into respectable gay married couples. This is, therefore, not an article about today’s Midge Decters, but about how contemporary same-sex marriage supporters rely on a characterisation of those of us who would or could not choose to marry as, to return to Vidal (Some Jews), “somehow evil or inadequate or dangerous.” As queer people who continue to question both the desirability and inevitability of marriage, we are ultimately concerned with thinking through the political consequences of the same-sex marriage campaign’s obsessive focus on normative sexuality and on the supposedly restorative function of the institution of marriage itself. Hateful Queers and Patient Gays Contemporary supporters of gay marriage, like Vidal so many years earlier, do often oppose conservative attempts to label homosexualists as inherently pathological. Tim Wright, the former convenor of “Equal Love,” one of Australia’s primary same-sex marriage campaign groups, directly addressing this in an opinion piece for Melbourne’s The Age newspaper, writes, “Every so often, we hear them in the media calling homosexuals promiscuous or sick.” Disputing this characterisation, Wright supplants it with an image of patient lesbians and gay men “standing at the altar.” Unlike Vidal, however, Wright implicitly accepts the link between promiscuity and pathology. For Wright, homosexuals are not sick precisely because, and only to the extent that they accept, a forlorn chastity, waiting for their respectable monogamous sexuality to be sanctified through matrimony. A shared moral framework based upon conservative norms is a notable feature of same-sex marriage debates. Former Rainbow Labor convenor Ryan Heath articulates this most clearly in his 2010 Griffith Review article, excerpts of which also appeared in the metropolitan Fairfax newspapers. In this article, Heath argues that marriage equality would provide a much-needed dose of responsibility to “balance” the rights that Australia has accorded to homosexuals. For Heath, Australia’s gay and lesbian communities have been given sexual freedoms by an indulgent adult (heterosexual) society, but are not sufficiently mature to develop the social responsibilities that go with them: “Like teenagers getting their hands on booze and cars and freedom from parental surveillance for the first time, Australia’s gay and lesbian communities have enthusiastically taken up their new rights.” For Heath, the immaturity of the (adult) gay community, with its lack of married role models, results in profound effects for same-sex attracted youth: Consider what the absence of role models, development paths, and stability might do to those who cannot marry. Is there no connection between this and the disproportionate numbers of suicides and risky and addictive behaviours found in gay communities? It is this immaturity, rather than the more typically blamed homophobic prejudice, bullying or persecution, that is for Heath the cause of the social problems that disproportionately affect same-sex attracted adolescents. Heath continues, asking why, after journalist Jonathan Rauch, any parent would want to “condemn their child to…‘a partnerless life in a sexual underworld’.” His appeal to well-meaning parental desires for the security and happiness of children echoes countless insidious commentaries about the tragedy of homosexual existence, such as Decter’s above. These same commentaries continue to be used to justify exclusionary and even violent reactions by families and communities when children reveal their (non-heterosexual) sexualities. As for so many social conservatives, for Heath it is inconceivable to view a partnerless life as anything other than tragedy. Like Wright, he is also convinced that if one must be partnerless it is far better to be forlornly chaste than to participate in an “underworld” focused primarily on promiscuous sex. The opinions of those condemned to this purgatorial realm, either through compulsion or their own immaturity, are of little interest to Heath. When he states that “No families and couples I have interviewed in my research on the topic want this insecure existence,” we are to understand that it is only the desires of these responsible adults that matter. In this way, Heath explicitly invokes the image of what Mariana Valverde has called the “respectable same-sex couple”, homosexualists who are socially acceptable because being “same-sex” is the only thing that differentiates them from the white, middle-class norm that continues to sit at the heart of Australian politics. Heath goes on to describe marriage as the best “social safety net”, adopting the fiscal rhetoric of conservatives such as former federal leader of the Liberal party, Malcolm Turnbull. Turnbull argued in 2012’s annual Michael Kirby lecture (a lecture organised by Southern Cross University’s School of Law and Justice in tribute to the retired gay High Court justice) that same-sex marriage would save the state money, as other relationship recognition such as the 2008 Rudd reforms have. In one of the few passages widely reported from his speech he states: “There will plainly be less demand for social services, medical expenses, hospital care if people, especially older people, like Michael [Kirby] and [partner] Johan, live together as opposed to being in lonely isolation consoled only by their respective cats.” Same-sex marriage is not simply a fight for equality but a fight to rescue homosexualists from the immiserated and emotionally impoverished lives that they, through their lack of maturity, have constructed for themselves, and which, after a brief sojourn in the sexual underworld, can only end in a lonely feline-focused existence funded by the responsible citizens that constitute the bulk of society. We are told by gay marriage advocates that the acceptance of proper adult relationships and responsibilities will not only cure the self-hatred of same-sexers, but simultaneously end the hatred expressed through homophobia and bullying. In the most recent Victorian state election, for example, the Greens ran an online Q&A session about their policies and positions in which they wrote the following in response to a question on relationship recognition: “It would create a more harmonious, less discriminatory society, more tolerant of diversity. It would also probably reduce bullying against same-sex attracted teenagers and lower the suicide rate.” This common position has been carefully unpicked by Rob Cover, who argues that while there may be benefits for the health of some adults in recognition of same-sex marriage, there is absolutely no evidence of a connection between this and youth suicide. He writes: “We are yet to have evidence that there are any direct benefits for younger persons who are struggling to cope with being bullied, humiliated, shamed and cannot (yet) envisage a liveable life and a happy future—let alone a marriage ceremony.” While same-sex marriage advocates consider themselves to be speaking for these same-sex attracted youth, offering them a happy future in the form of a wedding, Cover reminds us that these are not the same thing. As we have shown here, this is not a process of simple exclusion, but an erasure of the possibility of a life outside of heteronormative or “respectable”, coupledom. The “respectable same-sex couple”, like its respectable heterosexual counterpart, not only denies the possibility of full participation in adult society to those without partners but also refuses the lived experience of the many people like Vidal and Austen who do not accept the absolute equation of domesticity, responsibility, and sexual monogamy that the institution of marriage represents. A Good Institution? The connection between marriage and the mythical end of homophobia is not about evidence, as Cover rightly points out. Instead it is based on an ideological construction of marriage as an inherently valuable institution. Alongside this characterisation of marriage as a magical solution to homophobia and other social ills, comes the branding of other models of living, loving and having sex as inherently inferior and potentially harmful. In this, the rhetoric of conservatives and same-sex marriage advocates becomes disturbingly similar. Margaret Andrews, the wife of former Howard minister Kevin and a prominent (straight) marriage advocate, featured in the news a couple of years ago after making a public homophobic outburst directed at (queer) writer Benjamin Law. In response, Andrews outlined what for her were the clearly evident benefits of marriage: “For centuries, marriage has provided order, stability, and nurture for both adults and children. Indeed, the status of our marriages influences our well-being at least as much as the state of our finances.” Despite being on the apparent opposite of the debate, Amanda Villis and Danielle Hewitt from Doctors for Marriage Equality agree with Andrews about health benefits, including, significantly, those linked to sexual behaviour: It is also well known that people in long term monogamous relationships engage in far less risky sexual behaviour and therefore have significantly lower rates of sexually transmitted infections. Therefore legalisation of same sex marriage can lead to a reduction in the rates of sexually transmitted disease by decreasing stigma and discrimination and also promoting long term, monogamous relationships as an option for LGBTI persons. Here same-sex marriage is of benefit precisely because it eradicates the social risks of contagion and disease attributed to risky and promiscuous queers. To the extent that queers continue to suffer it can be attributed to the moral deficiency of their current lifestyle. This results in the need to “promote” marriage and marriage-like relationships. However, this need for promotion denies that marriage itself could be subject to discussion or debate and constructs it as both permanent and inevitable. Any discussion which might question the valuation of marriage is forestalled through the rhetoric of choice, as in the following example from a contributor to the “Equal Love” website: We understand that not everyone will want to get married, but there is no denying that marriage is a fundamental institution in Australian society. The right to be married should therefore be available to all those who choose to pursue it. It is a right that we chose to exercise. (Cole) This seemingly innocuous language of choice performs a number of functions. The first is that it seeks to disallow political debates about marriage by simply reducing critiques of the institution to a decision not to partake in it. In a process mirroring the construction of queers as inherently immature and adolescent, as discussed in the previous section, this move brands political critiques of marriage as historical remnants of an immature radicalism that has been trumped by liberal maturity. The contribution of Alyena Mohummadally and Catherine Roberts to Speak Now highlights this clearly. In this piece, Roberts is described as having used “radical feminism” as a teenage attempt to fill a “void” left by the lack of religion in her life. The teenage Roberts considered marriage “a patriarchal institution to be dismantled” (134). However, ten years later, now happily living with her partner, Roberts finds that “the very institutions she once riled against were those she now sought to be a part of” (137). Roberts’ marriage conversion, explained through a desire for recognition from Mohummadally’s Muslim family, is presented as simply a logical part of growing up, leaving behind the teenage commitment to radical politics along with the teenage attraction to “bars and nightclubs.” Not coincidentally, “life and love” taught Roberts to leave both of these things behind (134). The second consequence of arguments based on choice is that the possibility of any other terrain of choice is erased. This rhetoric thus gives marriage a false permanence and stability, failing to recognise that social institutions are vulnerable to change, and potentially to crisis. Beyond the same-sex marriage debates, the last fifty years have demonstrated the vulnerability of marriage to social change. Rising divorce rates, increasing acceptance of de facto relationships and the social recognition of domestic violence and rape within marriage have altered marriage inescapably, and forced questions about its inevitability (see: Stacey). This fact is recognised by conservatives, such as gay marriage opponent Patrick Parkinson who stated in a recent opinion piece in the Sydney Morning Herald that a “heartening aspect” of the “otherwise divisive” debate around gay marriage is that it has marked a “turnaround” in support for marriage, particularly among feminists, gays and other progressives. Malcolm Turnbull also explains his transition to support for same-sex marriage rights on the basis of this very premise: “I am very firmly of the view that families are the foundation of our society and that we would be a stronger society if more people were married, and by that I mean formally, legally married, and fewer were divorced.” He continued, “Are not the gays who seek the right to marry, to formalise their commitment to each other, holding up a mirror to the heterosexuals who are marrying less frequently and divorcing more often?” As Parkinson and Turnbull note, the decision to prioritise marriage is a decision to not only accept the fundamental nature of marriage as a social institution but to further universalise it as a social norm against the historical trends away from such normalisation. This is also acknowledged by campaign group Australian Marriage Equality who suggests that people like Parkinson and Turnbull who are “concerned about the preservation of marriage may do best to focus on ways to increase its appeal amongst the current population, rather than direct their energies towards the exclusion of a select group of individuals from its privileges.” Rather than challenging conservatism then, the gay marriage campaign aligns itself with Turnbull and Parkinson against the possibility of living otherwise embodied in the shadowy figure of the sexually irresponsible queer. The connection between ideological support for marriage and the construction of the “respectable homosexual couple” is made explicit by Heath in the essay quoted earlier. It is, he says, part of “the pattern of Western liberal history” to include “in an institution good people who make a good case to join.” The struggle for gay marriage, he argues, is linked to that of “workers to own property, Indigenous Australians to be citizens, women to vote.” By including these examples, Heath implicitly highlights the assimilationist dimension of this campaign, a dimension which has been importantly emphasised by Damien Riggs. Heath’s formulation denies the possibility of Indigenous sovereignty beyond assimilationist incorporation into the Australian state, just as it denies the possibility of a life of satisfying love and sex beyond marriage. More generally, Heath fails to acknowledge that none of these histories have disrupted the fundamental power dynamics at play: the benefits of property ownership accrue disproportionately to the rich, those of citizenship to white Australians, and political power remains primarily in the hands of men. Despite the protestations of gay marriage advocates there is no reason to believe that access to marriage would end homophobia while racism, class-based exploitation, and institutional sexism continue. This too, is part of the pattern of Western liberal history. Conclusion Our intention here is not to produce an anti-marriage manifesto—there are many excellent ones out there (see: Conrad)—but rather to note that gay marriage campaigns are not as historically innocuous as they present themselves to be. We are concerned that the rush to enter fully into institutions that, while changed, remain synonymous with normative (hetero)sexuality, has two unintended but nonetheless concerning consequences. Gay marriage advocates risk not only the discarding of a vision in which people may choose to not worship at the altar of the nuclear family, they also reanimate a new version of Decter’s self-hating gay. Political blogger Tim Dunlop encapsulates the political logic of gay marriage campaigns when he says, rather optimistically, that barring homosexualists from marriage “is the last socially acceptable way of saying you are not like us, you do not count, you matter less.” An alternative view proffered here is that saying yes to gay marriage risks abandoning a project that says we do not wish to be like you, not because we matter less, but because we see the possibility of different lives, and we refuse to accept a normative political logic that brands those lives as inferior. In casting this critique as adolescent, as something that a mature community should have grown out of, the same-sex marriage campaign rejects what we see as the most important social contributions that “same-sexers” have made. Where we think Vidal was mistaken back in 1981 was in his assertion that we “same-sexers” have been simply indifferent to the world of the “other-sexers.” We have also turned a critical eye upon “heterosexualist” existence, offering important critiques of a so-called adult or responsible life. It is this history that queer writer Sara Ahmed reminds us of, when she celebrates the angry queer at the family dinner table who refuses to simply succumb to a coercive demand to be happy and pleasant. A similar refusal can be found in queer critiques of the “dead citizenship” of heterosexuality, described by José Esteban Muñoz as: a modality of citizenship that is predicated on negation of liveness or presentness on behalf of a routinized investment in futurity. This narrative of futurity is most familiar to those who live outside of it. It is the story of the [sic] nation's all-consuming investment in the nuclear family, and its particular obsession with the children, an investment that instantly translates into the (monological) future. (399) In the clamour to fully assert their membership in the world of adult citizenship, same-sex marriage advocates negate the potential liveness and presentness of queer experience, opting instead for the routinised futurity that Muñoz warns against. Imagining ourselves as forlorn figures, standing with tear-stained cheeks and quivering lips at the altar, waiting for normative relationships and responsible citizenship is not the only option. Like Vidal and Austen, with whom we began, queers are already living, loving, and fucking, in and above our sexual underworlds, imagining that just possibly there may be other ways to live, both in the present and in constructing different futures. References Ahmed, Sara. The Promise of Happiness. Durham: Duke UP, 2010. 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