Journal articles on the topic 'Gel–tape casting'

A novel process, gel-tape-casting, is employed to fabricate LSGM thin dense sheets in aqueous AM system. The influences of powder properties, dispersant and other additives were discussed and relevant processing parameters were also explored. The slurry of LSGM with a high solid loading about 33 vol.% was successfully obtained.

Multilayer ZnO varistors were prepared by aqueous gel tape casting with water-soluble acrylamide as binder. 0.8wt% PAA dispersant was found to be the optimum concentration needed to prepare stable slurry. Plasticizer glycerol has a positive effect on the fluidity of the suspension and oxygen anti-polymerizing inhibitor PEG 2000 deteriorated the fluidity. The addition of 15wt. % PEG2000 eliminates the surface exfoliation absolutely due to the oxygenation of ether units. The solid loading of the slurry was about 71wt% compared to the custom acrylic formulation binder 60wt%. The multilayer ZnO varistors prepared by aqueous gel tape casting display comparable good electrical properties to those prepared by water-based tape casting using custom acrylic formulation binder which is attributed to the high solid loading of slurry.

Ni/YSZ cermet is the most widely used anode material for solid oxide fuel cell. In this paper, the NiO/YSZ green body was prepared by gel-tape casting, using 15%wt. starch as pore-forming agent, in the mixed polyvinyl alcohol and acrylamide systems. Ni/YSZ anode material was obtained after sintered at 1450°C for 2h and reduced at 800°C in H2 atmosphere for 4h. The anode porosity, XRD, TGA and microstructures were measured. YSZ formed a continuous network structure and Ni particles were dispersed homogeneously in the YSZ network. It is suitable to fabrication of anode material for solid oxide fuel cell.

The RBAO (Reaction Bonded Aluminum Oxide) process and water-based gel casting were combined to produce alumina platelet reinforced RBAO composites. In the RBAO process, a precursor powder mixture of Al metal and Al2O3 is reacted to form 100% ceramic. To obtain composites in which the platelets are highly aligned, tapes consisting of 10 vol.% homogeneously distributed alumina platelets and 90 vol.% RBAO precursor powder were made by water-based gel casting using an extended doctor blade arrangement. Pellets of textured composites were subsequently prepared by stacking sheets cut from the green tapes, and filter pressing. Randomly oriented platelet composites were made using the same starting powders and gelling procedure, but without the tape-casting step. Reaction bonding was carried out in a box furnace in air. Microstructures of the composites were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of platelet orientation on contact damage behavior was studied using a Hertzian indentation method. It was found that the textured composite exhibited improved damage resistance compared to the random composite.

Use starch, corn meal and activated carbon as pore-making agent, Ni-YSZ/YSZ composite ceramic green body was prepared by multiple gel-tape casting with acryloyl ammonium-polyvinyl alcohol. The specimen was sintered at 1450°C for 4h, then reduced in hydrogen atmosphere at 800°C for 4h, Ni-YSZ/YSZ composite ceramic disk was obtained, the porosity, thermal expansion coefficient, electrical properties and microstructures of the specimen was tested. The results showed that the porosity of Ni-YSZ/YSZ composite ceramic disk reaches about 30% when use starch as pore-making agent, expansion coefficient is proportional to porosity, both of them reduced with the temperature increased. The YSZ is continued and compact with network structure, Ni particulates are well distributed in it, suitable for intermediate temperature solid oxide fuel cell anode materials. Image analysis of SEM micrograph showed that the structure is loose, porous, uniform and compact in Ni/YSZ/YSZ multi-layer composite ceramics, which meet the requirement of intermediate temperature SOFC.

Techniques for producing near net shape ceramic components using aqueous forming processes are reviewed. Particular focus is on three dimensional, complex shape forming by gel casting and thin film forming by tape casting. Recent progress has been made in formulations that rely on dispersion of submicron ceramic particles in aqueous solutions containing polymers such as chitosan or poly vinyl alcohol and a temperature activated crosslinking agent (DHF, 2,5-dimethoxy- 2,5-dihydrofuran). These formulations can be produced to have low viscosity so that they can either be poured or injected into complex shape molds or cast into tapes. After casting, the suspension is heated to about 70 oC to activate the crosslinking agent. During crosslinking of the polymer, the rheological and mechanical behavior of the suspension is changed from liquid-like to solid-like. This allows the complex shaped bodies to be removed from the mold, dried and sintered. The strengthening of the cast tape due to crosslinking the polymer allows it to be dried without cracking. Rheological and mechanical behaviour, green and fired densities as well as examples of formed components will be presented. The green bodies can be readily machined with common high speed tool steel tools.

The all processes for manufacturing materials parts of solid oxide fuel cell (SOFC) are discussed in the paper. The films are made in one step by the ways of APS, VPS, EVD, which are usually used to produce the electrolyte and interconnect. The films are thin and good gas-resistance, but with relatively high cost. All parts of SOFC are made by the following ways, such as sol-gel, tape casting, tape calendaring and screen printing, which are suitable for manufacturing samples in industry with the cheapest process by co-sintered together ways.

AbstractEr3+-doped Ba0.85Ca0.15Ti0.9Zr0.1O3 (xEr-BCTZ, x = 0, 0.005, 0.01, 0.015) multifunctional thick films were prepared by the tape-casting method, using sol-gel-derived nano-sized powders as the matrix material. The surface morphologies, photoluminescence, and electrical properties were investigated. Dense microstructures with pure perovskite structure were obtained in the thick films. By doping an appropriate amount of Er3−, the samples exhibit superior up-conversion photoluminescence performance and simultaneously enhanced electrical performances. In addition, relatively higher texture fractions (with the largest value of 83.5%) were realized through introducing plate-like BaTiO3 templates to make the thick film grow by the [001]c orientation. And the ferro-/piezoelectric properties of the thick films were further improved, showing potential in the applications of micro-optoelectronic devices.

In the present work materials alternative to Ni/YSZ cermets anodes for Solid Oxide Fuel Cells (SOFCs) have been studied in order to overcome the problems related to catalytic deposition of carbon and the limited tolerance to sulphur. Anodes consisting of (La0.75Sr0.25)(Cr0.5Mn0.5)O3-δ (LSCM25) have been investigated with regard to synthesis and processing related problems. Single phase LSCM25 perovskites were synthesized by urea/nitrates gel combustion method and the as prepared powders were used to produce green tapes by tape casting processing. Thick LSCM25 substrates, suitable as anodes in anode supported SOFC fabrication, were successfully obtained by sintering of green LSCM25 laminates.

In this paper, several kinds of synthesis techniques were adopted; not only conventional solidstate reaction method but also solution synthesis techniques, including co-precipitation and hydrothermal synthesis, in addition to the gel-casting for complex shape of ceramic components and tape-casting of large scale thin plate for microwave IC. Different kinds of microwave ceramics were prepared, such as materials with low permittivity and high quality factor, moderate permittivity and good quality factor, and, high permittivity and reasonable quality factor, in addition to near zero of temperature coefficient of resonance frequency. Series of microwave devices were developed, for examples, dielectric resonators, dielectric filters, GPS antennas, communication connectors, and thin substrates for microwave IC.

In this paper, the gel-tape-casting process was applied to manufacture multilayer green sheets of SiCw /Al2O3 composite. The influence of SiCw, ball milling time and solids loading on the rheological behaviors of SiCw/Al2O3 slurries were investigated. It was found that the slurries exhibited a shear thinning behavior. The viscosity of the slurry increased with increasing of the fraction of SiCw. A stable slurry with 40 vol.% solids loading was prepared when 20 vol.% of SiCw was added. The flexural strength of the green sheet showed a trend of increasing firstly and then decreasing with SiCw increasing. The optimal mechanical properties of 40.2 MPa for flexural strength was obtained when SiCw contents was 20 vol.%. SEM observation indicated that significant whisker alignment was present in the composite tape, which was considered as one of parameters affecting toughening process.

BaTiO3 nanopowders prepared by sol-gel process were used for multilayer PTCR ceramics in order to utilize grain boundary effect and lower sintering temperature. The precursor gel was calcined at different temperatures and the powders were characterized by XRD and TEM. The average grain size was about 26nm when calcined at 800°C for 2h. Effects of acceptor/donor concentration and sintering temperature on PTCR ceramics were also investigated. The optimal concentration of the donor was found to be 0.6mol with the acceptor concentration being 1/8 of the donor. Multilayer PTCR elements were fabricated by tape-casting technique. The jump ratio of PTCR chips sintered at 1240°C was above 103 with the average grain size smaller than 1~2 μm, which is suitable for the multilayer PTCR elements.

Ceramic matrix composites reinforced with carbon nanotubes are becoming increasingly popular in industry due to their astonishing mechanical properties and taking into account the fact that advanced production technologies make carbon nanotubes increasingly affordable. In the present paper, the most convenient contemporary methods used for the compaction of molding masses composed of either technical ceramics or ceramic matrix composites reinforced with carbon nanotubes are surveyed. This stage that precedes debinding and sintering plays the key role in getting pore-free equal-density ceramics at the scale of mass production. The methods include: compaction in sealed and collector molds, cold isostatic and quasi-isostatic compaction; dynamic compaction methods, such as magnetic pulse, vibration, and ultrasonic compaction; extrusion, stamping, and injection; casting from aqueous and non-aqueous slips; tape and gel casting. Capabilities of mold-free approaches to produce precisely shaped ceramic bodies are also critically analyzed, including green ceramic machining and additive manufacturing technologies.

Barium titanate (BT) has attained research focus in recent past owing to considering its high dielectric constant and stealth capabilities in microwave region. Shape effects of BT viz. powder, micron size flakes, nano particles and nanotubes have been studied vastly for its stealth capabilities. Present study aims at the preparation of millimetric size barium titanate flakes (BTFs) via controlled sol-gel process followed by tape casting. BTFs were mixed in varied weight ratio (50-90 wt.%) with polyurethane resin to fabricate composite laminates. Electromagnetic properties measurement in X and Ku band revealed high values of real and imaginary permittivity. Reflection loss measurements demonstrated more than 20 dB loss in wide frequency range (11.4-13.6 GHz). For single layer microwave absorber, reflection loss values have been calculated and it is observed that calculated and measured reflection loss values are in good agreement to each other. Developed material can find applications in broadband radar signature reduction.

The B-F codoped nano-TiO2 powders were prepared by the sol-gel method. The surface of powders was modified by stearic acid. The visible light photodegradable PVC/B-F codoped nano-TiO2 composite films were prepared by tape casting processing. Solid-phase visible light photocatalytic degradation of the films were investigated with a 1000W xenon lamp and a ZJB 420 filter glass was used to cut off light of wavelength <420 nm. The weight-loss measurement, SEM, DSC of films were detected. Results showed that the weight loss of PVC/B-F codoped nano-TiO2 composite film (2%TiO2 w/w) is 16.9% after 120h UV irradiation, which is notably higher than that of both the pure PVC film and the PVC/nano-TiO2 composite film. Glass transition (Tg) is appeared for samples after 72h irradiation, and the Tg of PVC/B-F codoped nano-TiO2 composite film is the lowest of all samples. The surface of PVC/B-F codoped nano-TiO2 composite film was destroyed obviously by SEM photo.

The development of solid oxide fuel cells (SOFCs) and gas separation membranes for fossil (fuel?) power plants has previously suffered from cost issues like the manufacturing of the core components including i) the ceramic fuel cell and ii) the ceramic membrane, and from insufficient power density (current density or flow rate) on the stack, module or system level. Forschungszentrum Jülich has been working on SOFC development for 20 years, and on membrane development for 6 years. Both energy-related applications are based on similar materials systems, similar micro-structural features (porous-dense, coarse-fine), comparable application parameters (e.g. high temperature) and are manufactured with similar technologies. In the past the focus laid mostly on basic materials research and proving the functionality of the membranes or fuel cells. Meanwhile, one key topic has been the application of low-cost thin-film high-throughput manufacturing technologies. This includes the fabrication of the supports (mostly tape-casting), the coating with functional layers by ceramics technologies (screen printing, roll coating) and the reduction of sintering steps and temperatures. Additionally special thin-film technologies like sol-gel technique and electron beam evaporation / sputtering have also been applied for functional layers, depending on the functional necessities. The presentation gives an overview regarding the state-of-the-art in SOFC and gas separation membrane development at Forschungszentrum Jülich with an emphasis on the manufacturing technologies, resulting in optimized layer micro-structures and thickness. Additionally it summarizes the electrochemical and permeation data obtained so far.

Phosphate-bonded investment（PBI）ceramic mold materials have outstanding properties, such as rapid setting rate , moderate green strength and high temperature strength, and could be widely utilized in dental restoration and micro-casting of artistic products. However, fast hydration and gel rate of the phosphate-bonded ceramic slurry has been an obstacle to the wide applications of ceramic mold material for medium and large-size precision castings. This paper presents a new phosphate-bonded ceramic mold material by modifying the composition of refractory aggregates and additive agents, which is promising to be used for rapid ceramic mold casting for medium-size super alloy components. The results indicate that the properties of ceramic mold slurry including initial setting time and fluidity are suitable for complete embedding medium-scale patterns and get accurate duplicate of external configurations when the amount of boric acid is 1.11wt% and sodium tri-poly phosphate (STP) is 0.92wt%. The strength of ceramic mold material can resist impact force when pouring molten metal and easy take casting out from ceramic mold.

This article is a brief attempt to outline some of the difficulties involved in reconciling a film like Enemy of the State to itself. Perhaps a short synopsis: Will Smith plays a lawyer who unexpectedly encounters an old acquaintance who passes him something before being murdered. The acquaintance had become privy to a conspiracy involving members of the NSA who are responsible for the death of a politician. The politician was obstructing the passage of a new surveillance Bill, and the conspiracy is one of expanding the possibilities of invasive surveillance by the state, or at least rogue elements of the state. The conspirators work at watching and hounding Will Smith until they can retrieve the information. Jon Voight plays the lead conspirator. What this synopsis didn't mention is that Gene Hackman plays a reclusive, grouchy ex-NSA agent and surveillance expert. What the film doesn't mention is that he has done this before, in Francis Ford Coppola's early 1970s film The Conversation. Hackman's character in the earlier film has been described as "a private and suspicious man who lives with as little traceable human reference as possible, as if fearful of the threat of surveillance" (Thomson, America 185). Such a description is entirely applicable to his character in Enemy of the State. It is worth comparing certain aspects of these films not as simply an exercise in critical or textual analysis, but because the differences are illustrative of some key points pertaining to contemporary Hollywood film culture. One such point is that Enemy of the State can throw into relief the fraught relationship between special effects and the technologies of surveillance, a relation even more fraught for its visibility in an action film with a very large budget. The film of Tom Clancy's novel, Patriot Games, starred Harrison Ford as Jack Ryan. There is a sequence in that film that illustrates some of the binds in which Hollywood films can find themselves when they attempt to moralise about the invasive potential of image technologies. A live satellite feed has been arranged for American intelligence viewing of a raid on a suspected terrorist training camp. Low resolution, high angle pictures are recorded and relayed to the American audience of commando units acting on the intelligence analysis (image analysis) of that same audience. The data dies live to air. Ford's Jack Ryan is drawn into watching the fruits of his previous scrutiny. He is eventually disgusted by the armchair quarterbacking of the other viewers and turns away from the images. Not before we, the viewers have had enough time to recognise what we have seen and perhaps reacted to the "gee whiz" potential of that coupling of new image and new image technology. Ryan's disgust is actually a little intrusive on our appreciation. But there is enough of Indiana Jones in Jack Ryan for us to be convinced he truly believes in the integrity of acting at first-hand rather than at an inter-continental remove. Harrison Ford's character in Coppola's The Conversation has no adventurer's taint. More like one of the replicants in Blade Runner, with a liberal dose of Richard Gere's pretty poise in American Gigolo. Ford is genuinely bland and genuinely menacing under Coppola's direction in The Conversation. That film, made almost as a penitential act after The Godfather1, confines its special effects budget almost entirely to the soundtrack. Sounds, and their editing, are much of the surveillance of the film. Gene Hackman plays Harry Caul, "the best bugger on the West Coast", a surveillance expert for hire, with a somewhat shadowy background of bugs half-legend. Part of that background concerns a triple murder where information he provided to a client caused the deaths of three people. Caul is haunted by the chance of that happening again. Hired to bug a couple conversing in a crowded square, Caul and his people take photos and record a conversation that he subsequently edits into audibility. Increasingly afraid that the infidelity his surveillance uncovered will cause the deaths of the couple involved, Harry attempts to prevent the transfer of the data. His attempts are for nothing, as it turns out the couple murder the corporate executive husband of the overheard woman, Caul himself is under their surveillance, or perhaps just the surveillance of corporate underling Harrison Ford. Caul demolishes his apartment at the end of the film, fruitlessly trying to find the bugs. Enemy of the State's most basic problem is the casting in the male lead role of Will Smith. This is a film about paranoia, and release publicity deployed paranoiac pop culture jokes of some staleness such as "You're not paranoid if they really are out to get you". The male lead is scripted as the site at which real anxieties about intrusive levels of government surveillance are to be deployed and made visible. Will Smith, with Independence Day and Men in Black recently behind him, does not function in such a register. It is the persona of the comedian that lingers (and is cultivated by directors and producers) over Smith as an actor, a persona in part defined by the desire for attention, the wish for surveillance. At some level, the film is Smith's wish-fulfilment of more attention than he can handle -- except that he does handle it. Think of how different the entire film would have been with Denzel Washington as the lead, or Spike Lee. The fact is that conspiracies have become one of the great comforts of Western popular culture. The security of knowing that in spite of visible chaos someone out there knows what is really going on. The vogue for conspiracy is a nostalgia for metanarratives. In Enemy the conspirators are rogue elements of the State. What has been displaced is the entirely more edgy prospect suggested by Coppola's film, in which corporations commission acts of surveillance, or elements within corporations spy on each other. Rogues within rogues. Enemy, on the other hand, gives us the individual, the family man, in a desperate battle against the massed resources of the State. But this is not all there is to see or say. For me, perhaps the most interesting aspect of Enemy of the State is the relation between the special effects of the film and the invasive technologies of surveillance whose misuse the film is critiquing. This is not the time to address the issue of the varying aesthetics of special effects, save to note that there certainly are a range of aesthetic criteria on which spectator judgments about effects "quality" are made. At least one of these criteria is that special effects should visualise the new. Related to this is that they should provide new visual experiences2. Enemy has as its new visual experience the expanded resources of contemporary satellite surveillance technologies, along with various miniaturised surveillance devices. The only "conventional" big special effect is a building exploding. The rest of the film is engaged with using surveillance footage as special effects, in on-screen chases and pursuits. The crucial problem on which the film founders is that in generating viewing pleasure from the invasive application of these technologies, a double marking of the technology as special effect and the technology as invasive is made available to the viewer. The pleasure and the object of criticism share the same sign. The result is a vacillation. The screen jockeys in the film, childishly willing accomplices of Jon Voight and the rogue State, taking the pleasure of "cool" from a new image, are the viewers of the film, taking pleasure in a cool special effect. The attempts to render those spectators morally culpable for the plots of the film are, not surprisingly, shallow. To me, this film functions as a sort of limit case for special effects. It is as if the distance between effect and subject has been allowed to shrink a little too far, leading to a sort of collapse. As a note in closing, I would like to suggest that in the genre of the Hollywood action film, perhaps the only close relative of Enemy of the State is the "failed Arnie", Last Action Hero. Whereas that film deployed reflexivity about special effects and entertainment and hence to some degree trivialised the pleasures of its audience, it similarly marks a problematic convergence of special effects technology and spectators' acceptance of the moral consequences of vision. Footnotes David Thomson has written that: The Conversation has the reputation of being the intense chamber work of a director otherwise employed on large movies where spectacle takes precedence over private themes. The modesty of scale, after The Godfather, is regarded as a token of gravity. It was made clear as the picture opened that Coppola had used some of his own profits from the big movies to make this study in intimate anxiety. In sanctioning that gloss, Coppola appeared to be grappling with the demands of the industry and the inner responsibilities of the artist. The film is therefore a parable about talent, private satisfaction, and public duty. But it is the most despairing and horrified film Coppola has made. (Thomson, Overexposures 298) The first does not necessitate the second. It is entirely possible to visualise the new in such conventional fashion that it is meaningless to consider such to be a "new visual experience". References Thomson, David. America in the Dark: Hollywood and the Gift of Unreality. New York: William Morrow, 1975. Thomson, David. Overexposures: The Crisis in American Filmmaking. New York: William Morrow, 1981. Citation reference for this article MLA style: Paul Starr. "Special Effects and the Invasive Camera: Enemy of the State and The Conversation." M/C: A Journal of Media and Culture 2.2 (1999). [your date of access] <http://www.uq.edu.au/mc/9903/enemy.php>. Chicago style: Paul Starr, "Special Effects and the Invasive Camera: Enemy of the State and The Conversation," M/C: A Journal of Media and Culture 2, no. 2 (1999), <http://www.uq.edu.au/mc/9903/enemy.php> ([your date of access]). APA style: Paul Starr. (1999) Special effects and the invasive camera: Enemy of the State and The Conversation. M/C: A Journal of Media and Culture 2(2). <http://www.uq.edu.au/mc/9903/enemy.php> ([your date of access]).

Introduction This article explores the changing relational quality of “the shadow of hierarchy”, in the context of the merging of platforms with infrastructure as the source of the shadow of hierarchy. In governance and regulatory studies, the shadow of hierarchy (or variations thereof), describes the space of influence that hierarchal organisations and infrastructures have (Héritier and Lehmkuhl; Lance et al.). A shift in who/what casts the shadow of hierarchy will necessarily result in changes to the attendant relational values, logics, and (techno)socialities that constitute the shadow, and a new arrangement of shadow that presents new challenges and opportunities. This article reflects on relevant literature to consider two different ways the shadow of hierarchy has qualitatively changed as platforms, rather than infrastructures, come to cast the shadow of hierarchy – an increase in scalability; and new socio-technical arrangements of (non)participation – and the opportunities and challenges therein. The article concludes that more concerted efforts are needed to design the shadow, given a seemingly directionless desire to enact data-driven solutions. The Shadow of Hierarchy, Infrastructures, and Platforms The shadow of hierarchy refers to how institutional, infrastructural, and organisational hierarchies create a relational zone of influence over a particular space. This commonly refers to executive decisions and legislation created by nation states, which are cast over private and non-governmental actors (Héritier and Lehmkuhl, 2). Lance et al. (252–53) argue that the shadow of hierarchy is a productive and desirable thing. Exploring the shadow of hierarchy in the context of how geospatial data agencies govern their data, Lance et al. find that the shadow of hierarchy enables the networked governance approaches that agencies adopt. This is because operating in the shadow of institutions provides authority, confers bureaucratic legitimacy and top-down power, and offers financial support. The darkness of the shadow is thus less a moral or ethicopolitical statement (such as that suggested by Fisher and Bolter, who use the idea of darkness to unpack the morality of tourism involving death and human suffering), and instead a relationality; an expression of differing values, logics, and (techno)socialities internal and external to those infrastructures and institutions that cast it (Gehl and McKelvey). The shadow of hierarchy might therefore be thought of as a field of relational influences and power that a social body casts over society, by virtue of a privileged position vis-a-vis society. It modulates society’s “light”; the resources (Bourdieu) and power relationships (Foucault) that run through social life, as parsed through a certain institutional and infrastructural worldview (the thing that blocks the light to create the shadow). In this way the shadow of hierarchy is not a field of absolute blackness that obscures, but instead a gradient of light and dark that creates certain effects. The shadow of hierarchy is now, however, also being cast by decentralised, privately held, and non-hierarchal platforms that are replacing or merging with public infrastructure, creating new social effects. Platforms are digital, socio-technical systems that create relationships between different entities. They are most commonly built around a relatively fixed core function (such as a social media service like Facebook), that then interacts with a peripheral set of complementors (advertising companies and app developers in the case of social media; Baldwin and Woodard), to create new relationships, forms of value, and other interactions (van Dijck, The Culture of Connectivity). In creating these relationships, platforms become inherently political (Gillespie), shaping relationships and content on the platform (Suzor) and in embodied life (Ajunwa; Eubanks). While platforms are often associated with optional consumer platforms (such as streaming services like Spotify), they have increasingly come to occupy the place of public infrastructure, and act as a powerful enabler to different socio-technical, economic, and political relationships (van Dijck, Governing Digital Societies). For instance, Plantin et al. argue that platforms have merged with infrastructures, and that once publicly held and funded institutions and essential services now share many characteristics with for-profit, privately held platforms. For example, Australia has had a long history of outsourcing employment services (Webster and Harding), and nearly privatised its entire visa processing data infrastructure (Jenkins). Platforms therefore have a greater role in casting the shadow of hierarchy than before. In doing so, they cast a shadow that is qualitatively different, modulated through a different set of relational values and (techno)socialities. Scalability A key difference and selling point of platforms is their scalability; since they can rapidly and easily up- and down-scale their functionalities in a way that traditional infrastructure cannot (Plantin et al.). The ability to respond “on-demand” to infrastructural requirements has made platforms the go-to service delivery option in the neo-liberalised public infrastructure environment (van Dijck, Governing Digital Societies). For instance, services providers like Amazon Web Services or Microsoft Azure provide on demand computing capacity for many nations’ most valuable services, including their intelligence and security capabilities (Amoore, Cloud Ethics; Konkel). The value of such platforms to government lies in the reduced cost and risk that comes with using rented capabilities, and the enhanced flexibility to increase or decrease their usage as required, without any of the economic sunk costs attached to owning the infrastructure. Scalability is, however, not just about on-demand technical capability, but about how platforms can change the scale of socio-technical relationships and services that are mediated through the platform. This changes the relational quality of the shadow of hierarchy, as activities and services occurring within the shadow are now connected into a larger and rapidly modulating scale. Scalability allows the shadow of hierarchy to extend from those in proximity to institutions to the broader population in general. For example, individual citizens can more easily “reach up” into governmental services and agencies as a part of completing their everyday business through platform such as MyGov in Australia (Services Australia). Using a smartphone application, citizens are afforded a more personalised and adaptive experience of the welfare state, as engaging with welfare services is no-longer tied to specific “brick-and-mortar” locations, but constantly available through a smartphone app and web portal. Multiple government services including healthcare and taxation are also connected to this platform, allowing users to reach across multiple government service domains to complete their personal business, seeking information and services that would have once required separate communications with different branches of government. The individual’s capacities to engage with the state have therefore upscaled with this change in the shadow, retaining a productivity and capacity enhancing quality that is reminiscent of older infrastructures and institutions, as the individual and their lived context is brought closer to the institutions themselves. Scale, however, comes with complications. The fundamental driver for scalability and its adaptive qualities is datafication. This means individuals and organisations are inflecting their operational and relational logics with the logic of datafication: a need to capture all data, at all times (van Dijck, Datafication; Fourcade and Healy). Platforms, especially privately held platforms, benefit significantly from this, as they rely on data to drive and refine their algorithmic tools, and ultimately create actionable intelligence that benefits their operations. Thus, scalability allows platforms to better “reach down” into individual lives and different social domains to fuel their operations. For example, as public transport services become increasingly datafied into mobility-as-a-service (MAAS) systems, ride sharing and on-demand transportation platforms like Uber and Lyft become incorporated into the public transport ecosystem (Lyons et al.). These platforms capture geospatial, behavioural, and reputational data from users and drivers during their interactions with the platform (Rosenblat and Stark; Attoh et al.). This generates additional value, and profits, for the platform itself with limited value returned to the user or the broader public it supports, outside of the transport service. It also places the platform in a position to gain wider access to the population and their data, by virtue of operating as a part of a public service. In this way the shadow of hierarchy may exacerbate inequity. The (dis)benefits of the shadow of hierarchy become unevenly spread amongst actors within its field, a function of an increased scalability that connects individuals into much broader assemblages of datafication. For Eubank, this can entrench existing economic and social inequalities by forcing those in need to engage with digitally mediated welfare systems that rely on distant and opaque computational judgements. Local services are subject to increased digital surveillance, a removal of agency from frontline advocates, and algorithmic judgement at scale. More fortunate citizens are also still at risk, with Nardi and Ekbia arguing that many digitally scaled relationships are examples of “heteromation”, whereby platforms convince actors in the platform to labour for free, such as through providing ratings which establish a platform’s reputational economy. Such labour fuels the operation of the platform through exploiting users, who become both a product/resource (as a source of data for third party advertisers) and a performer of unrewarded digital labour, such as through providing user reviews that help guide a platform’s algorithm(s). Both these examples represent a particularly disconcerting outcome for the shadow of hierarchy, which has its roots in public sector institutions who operate for a common good through shared and publicly held infrastructure. In shifting towards platforms, especially privately held platforms, value is transmitted to private corporations and not the public or the commons, as was the case with traditional infrastructure. The public also comes to own the risks attached to platforms if they become tied to public services, placing a further burden on the public if the platform fails, while reaping none of the profit and value generated through datafication. This is a poor bargain at best. (Non)Participation Scalability forms the basis for a further predicament: a changing socio-technical dynamic of (non)participation between individuals and services. According to Star (118), infrastructures are defined through their relationships to a given context. These relationships, which often exist as boundary objects between different communities, are “loosely structured in common use, and become tightly bound in particular locations” (Star, 118). While platforms are certainly boundary objects and relationally defined, the affordances of cloud computing have enabled a decoupling from physical location, and the operation of platforms across time and space through distributed digital nodes (smartphones, computers, and other localised hardware) and powerful algorithms that sort and process requests for service. This does not mean location is not important for the cloud (see Amoore, Cloud Geographies), but platforms are less likely to have a physically co-located presence in the same way traditional infrastructures had. Without the same institutional and infrastructural footprint, the modality for participating in and with the shadow of hierarchy that platforms cast becomes qualitatively different and predicated on digital intermediaries. Replacing a physical and human footprint with algorithmically supported and decentralised computing power allows scalability and some efficiency improvements, but it also removes taken-for-granted touchpoints for contestation and recourse. For example, ride-sharing platform Uber operates globally, and has expressed interest in operating in complement to (and perhaps in competition with) public transport services in some cities (Hall et al.; Conger). Given that Uber would come to operate as a part of the shadow of hierarchy that transport authorities cast over said cities, it would not be unreasonable to expect Uber to be subject to comparable advocacy, adjudication, transparency, and complaint-handling requirements. Unfortunately, it is unclear if this would be the case, with examples suggesting that Uber would use the scalability of its platform to avoid these mechanisms. This is revealed by ongoing legal action launched by concerned Uber drivers in the United Kingdom, who have sought access to the profiling data that Uber uses to manage and monitor its drivers (Sawers). The challenge has relied on transnational law (the European Union’s General Data Protection Regulation), with UK-based drivers lodging claims in Amsterdam to initiate the challenge. Such costly and complex actions are beyond the means of many, but demonstrate how reasonable participation in socio-technical and governance relationships (like contestations) might become limited, depending on how the shadow of hierarchy changes with the incorporation of platforms. Even if legal challenges for transparency are successful, they may not produce meaningful change. For instance, O’Neil links algorithmic bias to mathematical shortcomings in the variables used to measure the world; in the creation of irritational feedback loops based on incorrect data; and in the use of unsound data analysis techniques. These three factors contribute to inequitable digital metrics like predictive policing algorithms that disproportionately target racial minorities. Large amounts of selective data on minorities create myopic algorithms that direct police to target minorities, creating more selective data that reinforces the spurious model. These biases, however, are persistently inaccessible, and even when visible are often unintelligible to experts (Ananny and Crawford). The visibility of the technical “installed base” that support institutions and public services is therefore not a panacea, especially when the installed base (un)intentionally obfuscates participation in meaningful engagement like complaints handling. A negative outcome is, however, also not an inevitable thing. It is entirely possible to design platforms to allow individual users to scale up and have opportunities for enhanced participation. For instance, eGovernance and mobile governance literature have explored how citizens engage with state services at scale (Thomas and Streib; Foth et al.), and the open government movement has demonstrated the effectiveness of open data in understanding government operations (Barns; Janssen et al.), although these both have their challenges (Chadwick; Dawes). It is not a fantasy to imagine alternative configurations of the shadow of hierarchy that allow more participatory relationships. Open data could facilitate the governance of platforms at scale (Box et al.), where users are enfranchised into a platform by some form of membership right and given access to financial and governance records, in the same way that corporate shareholders are enfranchised, facilitated by the same app that provides a service. This could also be extended to decision making through voting and polling functions. Such a governance form would require radically different legal, business, and institutional structures to create and enforce this arrangement. Delacoix and Lawrence, for instance, suggest that data trusts, where a trustee is assigned legal and fiduciary responsibility to achieve maximum benefit for a specific group’s data, can be used to negotiate legal and governance relationships that meaningfully benefit the users of the trust. Trustees can be instructed to only share data to services whose algorithms are regularly audited for bias and provide datasets that are accurate representations of their users, for instance, avoiding erroneous proxies that disrupt algorithmic models. While these developments are in their infancy, it is not unreasonable to reflect on such endeavours now, as the technologies to achieve these are already in use. Conclusions There is a persistent myth that data will yield better, faster, more complete results in whatever field it is applied (Lee and Cook; Fourcade and Healy; Mayer-Schönberger and Cukier; Kitchin). This myth has led to data-driven assemblages, including artificial intelligence, platforms, surveillance, and other data-technologies, being deployed throughout social life. The public sector is no exception to this, but the deployment of any technological solution within the traditional institutions of the shadow of hierarchy is fraught with challenges, and often results in failure or unintended consequences (Henman). The complexity of these systems combined with time, budgetary, and political pressures can create a contested environment. It is this environment that moulds societies' light and resources to cast the shadow of hierarchy. Relationality within a shadow of hierarchy that reflects the complicated and competing interests of platforms is likely to present a range of unintended social consequences that are inherently emergent because they are entering into a complex system – society – that is extremely hard to model. The relational qualities of the shadow of hierarchy are therefore now more multidimensional and emergent, and experiences relating to socio-technical features like scale, and as a follow-on (non)participation, are evidence of this. Yet by being emergent, they are also directionless, a product of complex systems rather than designed and strategic intent. This is not an inherently bad thing, but given the potential for data-system and platforms to have negative or unintended consequences, it is worth considering whether remaining directionless is the best outcome. There are many examples of data-driven systems in healthcare (Obermeyer et al.), welfare (Eubanks; Henman and Marston), and economics (MacKenzie), having unintended and negative social consequences. Appropriately guiding the design and deployment of theses system also represents a growing body of knowledge and practical endeavour (Jirotka et al.; Stilgoe et al.). Armed with the knowledge of these social implications, constructing an appropriate social architecture (Box and Lemon; Box et al.) around the platforms and data systems that form the shadow of hierarchy should be encouraged. This social architecture should account for the affordances and emergent potentials of a complex social, institutional, economic, political, and technical environment, and should assist in guiding the shadow of hierarchy away from egregious challenges and towards meaningful opportunities. To be directionless is an opportunity to take a new direction. The intersection of platforms with public institutions and infrastructures has moulded society’s light into an evolving and emergent shadow of hierarchy over many domains. With the scale of the shadow changing, and shaping participation, who benefits and who loses out in the shadow of hierarchy is also changing. Equipped with insights into this change, we should not hesitate to shape this change, creating or preserving relationalities that offer the best outcomes. Defining, understanding, and practically implementing what the “best” outcome(s) are would be a valuable next step in this endeavour, and should prompt considerable discussion. If we wish the shadow of hierarchy to continue to be productive, then finding a social architecture to shape the emergence and directionlessness of socio-technical systems like platforms is an important step in the continued evolution of the shadow of hierarchy. References Ajunwa, Ifeoma. “Age Discrimination by Platforms.” Berkeley J. Emp. & Lab. L. 40 (2019): 1-30. Amoore, Louise. Cloud Ethics: Algorithms and the Attributes of Ourselves and Others. Durham: Duke University Press, 2020. ———. “Cloud Geographies: Computing, Data, Sovereignty.” Progress in Human Geography 42.1 (2018): 4-24. Ananny, Mike, and Kate Crawford. “Seeing without Knowing: Limitations of the Transparency Ideal and Its Application to Algorithmic Accountability.” New Media & Society 20.3 (2018): 973–89. Attoh, Kafui, et al. “‘We’re Building Their Data’: Labor, Alienation, and Idiocy in the Smart City.” Environment and Planning D: Society and Space 37.6 (2019): 1007-24. Baldwin, Carliss Y., and C. Jason Woodard. “The Architecture of Platforms: A Unified View.” Platforms, Markets and Innovation. Ed. Annabelle Gawer. Cheltenham: Edward Elgar, 2009. 19–44. Barns, Sarah. “Mine Your Data: Open Data, Digital Strategies and Entrepreneurial Governance by Code.” Urban Geography 37.4 (2016): 554–71. Bourdieu, Pierre. Distinction: A Social Critique of the Judgement of Taste. Cambridge, MA: Harvard University Press, 1984. Box, Paul, et al. Data Platforms for Smart Cities – A Landscape Scan and Recommendations for Smart City Practice. Canberra: CSIRO, 2020. Box, Paul, and David Lemon. The Role of Social Architecture in Information Infrastructure: A Report for the National Environmental Information Infrastructure (NEII). Canberra: CSIRO, 2015. Chadwick, Andrew. “Explaining the Failure of an Online Citizen Engagement Initiative: The Role of Internal Institutional Variables.” Journal of Information Technology & Politics 8.1 (2011): 21–40. Conger, Kate. “Uber Wants to Sell You Train Tickets. And Be Your Bus Service, Too.” The New York Times, 7 Aug. 2019. 19 Jan. 2021. <https://www.nytimes.com/2019/08/07/technology/uber-train-bus-public-transit.html>. Dawes, Sharon S. “The Evolution and Continuing Challenges of E‐Governance.” Public Administration Review 68 (2008): 86–102. Delacroix, Sylvie, and Neil D. Lawrence. “Bottom-Up Data Trusts: Disturbing the ‘One Size Fits All’ Approach to Data Governance.” International Data Privacy Law 9.4 (2019): 236-252. Eubanks, Virginia. Automating Inequality: How High-Tech Tools Profile, Police, and Punish the Poor. New York: St. Martin’s Press, 2018. Fisher, Joshua A., and Jay David Bolter. “Ethical Considerations for AR Experiences at Dark Tourism Sites”. IEEE Explore 29 April. 2019. 13 Apr. 2021 <https://ieeexplore.ieee.org/document/8699186>. Foth, Marcus, et al. From Social Butterfly to Engaged Citizen: Urban Informatics, Social Media, Ubiquitous Computing, and Mobile Technology to Support Citizen Engagement. Cambridge MA: MIT Press, 2011. Fourcade, Marion, and Kieran Healy. “Seeing like a Market.” Socio-Economic Review, 15.1 (2017): 9–29. Gehl, Robert, and Fenwick McKelvey. “Bugging Out: Darknets as Parasites of Large-Scale Media Objects.” Media, Culture & Society 41.2 (2019): 219–35. Gillespie, Tarleton. “The Politics of ‘Platforms.’” New Media & Society 12.3 (2010): 347–64. Hall, Jonathan D., et al. “Is Uber a Substitute or Complement for Public Transit?” Journal of Urban Economics 108 (2018): 36–50. Henman, Paul. “Improving Public Services Using Artificial Intelligence: Possibilities, Pitfalls, Governance.” Asia Pacific Journal of Public Administration 42.4 (2020): 209–21. Henman, Paul, and Greg Marston. “The Social Division of Welfare Surveillance.” Journal of Social Policy 37.2 (2008): 187–205. Héritier, Adrienne, and Dirk Lehmkuhl. “Introduction: The Shadow of Hierarchy and New Modes of Governance.” Journal of Public Policy 28.1 (2008): 1–17. Janssen, Marijn, et al. “Benefits, Adoption Barriers and Myths of Open Data and Open Government.” Information Systems Management 29.4 (2012): 258–68. Jenkins, Shannon. “Visa Privatisation Plan Scrapped, with New Approach to Tackle ’Emerging Global Threats’.” The Mandarin. 23 Mar. 2020. 19 Jan. 2021 <https://www.themandarin.com.au/128244-visa-privatisation-plan-scrapped-with-new-approach-to-tackle-emerging-global-threats/>. Jirotka, Marina, et al. “Responsible Research and Innovation in the Digital Age.” Communications of the ACM 60.6 (2016): 62–68. Kitchin, Rob. The Data Revolution: Big Data, Open Data, Data Infrastructures and Their Consequences. Thousand Oaks, CA: Sage, 2014. Konkel, Frank. “CIA Awards Secret Multibillion-Dollar Cloud Contract.” Nextgov 20 Nov. 2020. 19 Jan. 2021 <https://www.nextgov.com/it-modernization/2020/11/exclusive-cia-awards-secret-multibillion-dollar-cloud-contract/170227/>. Lance, Kate T., et al. “Cross‐Agency Coordination in the Shadow of Hierarchy: ‘Joining up’Government Geospatial Information Systems.” International Journal of Geographical Information Science, 23.2 (2009): 249–69. Lee, Ashlin J., and Peta S. Cook. “The Myth of the ‘Data‐Driven’ Society: Exploring the Interactions of Data Interfaces, Circulations, and Abstractions.” Sociology Compass 14.1 (2020): 1–14. Lyons, Glenn, et al. “The Importance of User Perspective in the Evolution of MaaS.” Transportation Research Part A: Policy and Practice 121(2019): 22-36. MacKenzie, Donald. “‘Making’, ‘Taking’ and the Material Political Economy of Algorithmic Trading.” Economy and Society 47.4 (2018): 501-23. Mayer-Schönberger, V., and K. Cukier. Big Data: A Revolution That Will Change How We Live, Work and Think. London: John Murray, 2013. Michel Foucault. Discipline and Punish. London: Penguin, 1977. Nardi, Bonnie, and Hamid Ekbia. Heteromation, and Other Stories of Computing and Capitalism. Cambridge, MA: MIT Press, 2017. O’Neil, Cathy. Weapons of Math Destruction – How Big Data Increases Inequality and Threatens Democracy. London: Penguin, 2017. Obermeyer, Ziad, et al. “Dissecting Racial Bias in an Algorithm Used to Manage the Health of Populations.” Science 366.6464 (2019): 447-53. Plantin, Jean-Christophe, et al. “Infrastructure Studies Meet Platform Studies in the Age of Google and Facebook.” New Media & Society 20.1 (2018): 293–310. Rosenblat, Alex, and Luke Stark. “Algorithmic Labor and Information Asymmetries: A Case Study of Uber’s Drivers.” International Journal of Communication 10 (2016): 3758–3784. Sawers, Paul. “Uber Drivers Sue for Data on Secret Profiling and Automated Decision-Making.” VentureBeat 20 July. 2020. 19 Jan. 2021 <https://venturebeat.com/2020/07/20/uber-drivers-sue-for-data-on-secret-profiling-and-automated-decision-making/>. Services Australia. About MyGov. Services Australia 19 Jan. 2021. 19 Jan. 2021 <https://www.servicesaustralia.gov.au/individuals/subjects/about-mygov>. Star, Susan Leigh. “Infrastructure and Ethnographic Practice: Working on the Fringes.” Scandinavian Journal of Information Systems 14.2 (2002):107-122. Stilgoe, Jack, et al. “Developing a Framework for Responsible Innovation.” Research Policy 42.9 (2013):1568-80. Suzor, Nicolas. Lawless: The Secret Rules That Govern Our Digital Lives. Cambridge: Cambridge University Press, 2019. Thomas, John Clayton, and Gregory Streib. “The New Face of Government: Citizen‐initiated Contacts in the Era of E‐Government.” Journal of Public Administration Research and Theory 13.1 (2003): 83-102. Van Dijck, José. “Datafication, Dataism and Dataveillance: Big Data between Scientific Paradigm and Ideology.” Surveillance & Society 12.2 (2014): 197–208. ———. “Governing Digital Societies: Private Platforms, Public Values.” Computer Law & Security Review 36 (2020) 13 Apr. 2021 <https://www.sciencedirect.com/science/article/abs/pii/S0267364919303887>. ———. The Culture of Connectivity: A Critical History of Social Media. Oxford: Oxford University Press, 2013. Webster, Elizabeth, and Glenys Harding. “Outsourcing Public Employment Services: The Australian Experience.” Australian Economic Review 34.2 (2001): 231-42.