Sharing a meal: a diversity of performances engendered by a social innovation

ABSTRACT

This paper explores the dynamics between social innovations and socio-spatial transformations using practice theory as linking pin. Social innovations, such as the case study of a meal sharing platform here presented, are considered as proposals. Using social practice theory as a theoretical lens enables us to explain how the principles of the proposal’s design are moderated and appropriated by its users. Consequently, familiar routinized practices expand, becoming more complex and hybrid. It is in the performance of the practice that this complexity is revealed. Specific focus is on the socio-spatial transformations that social innovations propose. This paper shows how tactics of appropriation can result in trespassing the boundaries between private and public, and between domestic and communitarian space. This way, we connect social innovations to DIY-urbanism, showing how citizens appropriate urban space.     

Numerical simulation of a direct shear test on a rock joint using a bonded-particle model

Rock joints were numerically simulated, and an extensive series of direct shear tests were carried out using the code PFC3D. The feasibility of reproducing a rock joint using the contact bond model was demonstrated, and the effects of the geometrical features and the micro-properties of a joint on its shear behavior were examined. Asperity failure was observed from the micro-cracks and contact force distribution, as well as the stresses and displacements in shear and normal directions. A rough joint with a joint roughness coefficient (JRC) value ranging from 10 to 20 was produced in an intact sample by defining the joint-contacts along a predefined joint surface. To simulate a decrease in joint wall strength (JCS) caused by weathering and alterations, the bond strength between particles involved in the joint-contacts was reduced by up to 70%. The shear behavior and failure progress at a given stress corresponded well to those observed in laboratory tests. The friction coefficient was the most important factor governing the shear strength and dilation angle. The variation in joint roughness and contact bond strength had a larger effect on the cohesion than peak friction angle. In addition, a new approach to represent JRC and JCS values of a joint was proposed for practical use. A numerical 3D-profile scanning technique was developed to evaluate the actual JRC of the simulated joint, and the relationship between the JCS and the contact bond strength was investigated.     

Carotenoids in a food chain along a pollution gradient

Carotenoids are synthesized by plants, therefore insects and birds must obtain them from their diet. They function in pigmentation and as antioxidants. We studied the carotenoid profiles in a model food chain (plant-insect-bird) in an air pollution gradient to find out whether heavy metal pollution affects the transfer of carotenoids across the trophic levels. Birch leaves showed higher beta-carotene and, one of the birch species (Betula pendula), higher total carotenoids levels in the polluted area. There was no difference in the lutein concentration of caterpillars' food source, birch leaves, between the study areas. Autumnal moth larvae accumulated lutein more efficiently than beta-carotene while sawfly larvae accumulated beta-carotene over lutein. Because of different antioxidant profiles in different leaf chewing insects their sensitivity to pollution stress may differ. The lutein concentration of plasma and feathers of Great tit nestlings did not differ along the pollution gradient. The lack of difference in lutein concentration of autumnal moth larvae along pollution gradient may partly explain the lutein concentrations of Great tit nestlings, since the abundance of autumnal moth larvae peak during the nestling phase of Great tit. The lutein concentration of autumnal moth larvae was positively associated to circulating plasma lutein level of Great tit indicating the importance of carotenoid rich diet during the nestling phase. In addition, the higher the plasma lutein concentration the more lutein was deposited to feathers, irrespective of the other possible functions of lutein in nestlings. We found that carotenoid levels differed between the polluted and the unpolluted area especially at lower levels of food chain: in birches and in caterpillars.     

Microbiological Events After a Fire in a High-rise Building

Water used to control a fire on an upper floor in a highrise office building wetted furnishings and construction materials on lower floors and resulted in the amplification of microorganisms especially mesophilic and thermotolerant fungi. Concentrations of fungi in indoor air including Aspergillus, Penicillium and Paecilomyces approached or exceeded 10⁴ colony forming units per cubic meter (cfu/m³). Airborne endotoxin levels increased about 1 order of magnitude over background levels. Sampling for fungi using both culture plate impactors and spore traps showed that spores were migrating from water damaged to undamaged areas in the office complex. Elevator shafts traversing water damaged floors likely provided the major dispersion pathway of spores into occupied areas. Construction materials such as plaster ceilings that had been wetted during the fire but were free of visual fungal contamination were found to be strong fungal reservoirs after the building had thoroughly dried. Management of microbial contaminants after a fire in a highrise building is an important public health concern and therefore an essential aspect of building restoration.     

Venting a smoky fire in a hotel stairway

A fire started within a hotel staircase which smoke-logged the stairway. Smoke leaked on to adjoining lobbies which formed part of the escape routes for upper floor guests rendering them useless as a means of escape. Whilst the majority of guests were rescued from their bedroom windows by the fire brigade, one guest was overcome by smoke within the top floor lobby in attempting to escape. By calculating mass flow rates it has been possible to explain the observed movement of smoke and to demonstrate that with the venting of the stairway, there would have been very much less smoke logging of the lobbies with a resultant life and property saving.     

Development of a computational model simulating the interaction between a fire plume and a sprinkler spray

Numerical simulations to predict actual delivered densities (ADDs) of early suppression fast response (ESFR) sprinklers in heptane spray fire scenarios were sought. First, in order to supply input data for the development of numerical models and experimental data for validation of the models, four sets of measurements were carried out: the momentum and water flux distribution of two ESFR sprinkler sprays without fire; the temperature and axial velocities along the axis of free-burn fires; and the actual delivered densities. Then, a numerical model for a sprinkler spray was completed by assigning the representative drop size, mass flow rate, discharge speed and discharge angle of 275 trajectories in such a way that they produced reasonable agreement with the measured water flux distribution and spray momentum in the absence of fire. A numerical model for the free-burn fire was created by assigning a heat flux distribution on a horizontal surface and simulating a central, vertical air jet used in the experiment, varying parameters until a reasonable match was established with the measured temperatures and the axial velocities along the axis. Numerical computations of actual delivered densities were carried out by combining the water spray model and the free-burn fire model for different water flow rates of the sprinklers. The ADDs obtained from the simulations compared reasonably well with those from the measurements.     

Development of a dynamic model for a cone bolt

To ensure safety in underground excavations, it is important that the support systems used are capable of resisting the dynamic loads produced, for example, by rock bursts. In this paper, a dynamic simulation model for a cone bolt is proposed based on an experimental study. Drop weight tests were performed on resin-based cone bolts. These experiments revealed that the bolt has two energy absorption mechanisms: sliding in the resin and plastic deformation. To simulate this behaviour, a two degrees-of-freedom lumped-mass model is proposed. Experimentally, the proportions of sliding and plastic deformation were found to vary significantly from one test to another. To account for this variability, two methods are proposed to determine the value of the parameters governing the sliding of the bolt in the resin, whereas a dynamic force–elongation model is used to simulate the plastic deformation. Comparing the results of a simulation to experimental data proved that the constitutive elements of the model are appropriate to simulate the dynamic response of the cone bolt.     

Does a ward system produce a representative council?

Abstract

Toowoomba City Council introduced a ward system of representation to its municipal elections in 1982. The nature and quality of representation as affected by this change and an analysis of the ward boundaries as they relate to socially homogeneous areas of the city form the major discussion in this paper.     

A study of a fire on a diesel railcar

A fire broke out on a diesel railcar while running on a line of the Japan Railways Group. After an exhaustive investigation into the cause of the fire, it was found that the origin had been the lubricating oil of the engine. The lubricating oil vaporized from a long idling engine while the car was standing and accumulated in the exhaust silencer in considerable amounts. When the car was climbing up a long slope, the oil was exposed to a high-temperature exhaust gas and ignited. The flame attacked and melted the exhaust funnel, and eventually caused a fire.     

Betons a hautes performances,a granulats artificiels actifs

High strength concretes, in particular at early ages (more than 40 MPa at 3 days and up to 80 MPa at 7 days), are obtained by replacement of certain granular size ranges of sand or gravel by cement-active artificial aggregates in a given concrete composition elaborated with a local supply of aggregates and cement. The strengthening of the paste-aggregate bond by chemical reactions between the artificial aggregates and the cement also involves an improvement of other concrete performances and not only of mechanical strengths. The cracking ability is decreased, the wear strength is higher, and water permeability is low or even nil for certain compositions. The laboratory results are confirmed by tests on the site and show the possibility of achieving high strength concretes without any particular selection of cement and natural aggregates.     

On underfloor air-conditioning of a room containing a distributed heat source and a localised heat source

This paper studies air flow in an air-conditioned room containing a distributed heat source and a localised heat source, into which cool air is supplied at low momentum through openings at a low level, and from which old air is extracted from a high level. This situation may be analogous to an auditorium containing a distributed audience and a localised group of actors and lighting on a stage, into which cool air is distributed from underneath the seating, and from which old air is removed through a ceiling, for example. Using a combination of a theoretical model and laboratory experiments, the paper shows that, in such conditions, if the localised heating is sufficiently strong compared to the distributed heating, the room will become stratified into two layers at steady state. A layer of warm air lies atop a cooler layer that attains a temperature above that of the supply air. This temperature structure depends primarily on the supply air flow rate and the ratio of the distributed heating to the total heat flux. For a room with fixed heating, increasing the supply air flow rate raises the interface between the upper and lower layers, while cooling both layers. The temperature in the upper layer depends on the total heat flux, but the temperature in the lower layer depends on the flux of distributed heating. For a room with a fixed supply air flow rate and a fixed total heat flux, increasing the strength of distributed heating warms the lower layer, but does not affect the temperature in the upper layer. Such increase in the strength of distributed heating also raises the interface. To achieve sufficient ventilation and thermal comfort in an occupied lower zone while keeping any pocket of uncomfortably warm air well above it, cool air needs to be supplied within an appropriate range of flow rates, which depends on the ratio of the distributed heating to the total heat flux. The paper shows how to determine such appropriate ranges of flow rates for different heating ratios, using the model.     

Case study of a rainwater recovery system in a commercial building with a large roof

This paper describes a prototype rainwater recovery system that has been fitted within a supermarket. In this system, rainwater is recovered from the roof structure, collected and then used to satisfy part of the domestic cold water requirements of the supermarket (for toilet flushing). The design and commissioning of the system installed is first described. The system has been fitted with a monitoring system, which has been used to record the water usage and to estimate the rainwater recovered for use in the supermarket over approximately an 8-month period. The results are used to calculate the collection efficiency of the system compared to potential gains determined from local rainfall data. This data has also been used to calculate the revenue cost savings for this system. The additional capital cost of this system has been estimated and this has been used to calculate a payback period of 12 years, based upon a collection efficiency of 57.4%. Alternative payback periods for different locations in the UK are also discussed. Finally, this paper considers the effects of alternative roof and tank sizes on system economics. This shows that tank size is critical and that different configurations may be used to achieve payback periods approaching 4 years.     

The Environmental Impact of a Chemical Spill from a Timber-Treatment Works on a Lowland River System

A major timber-preservative spillage, resulting from a fire at a timber yard, released substantial quantities of tributyltin and lindane (g hexachlorocyclohexane) into the River Bourne - a tributary of the River Thames. This paper describes the chemical and biological effects resulting from the incident. Water-column concentrations in the River Bourne South ranged from below detection limits to 5200 μg/l and 3700 μg/l for tributyltin and lindane respectively, with contamination extending 80 km into the Thames estuary. The high concentration of pollutants caused extensive fish mortality and virtually eradicated the invertebrate population in the immediate vicinity of the spill. Although sediment monitoring revealed initially high surficial sediment concentrations of tributyltin (3300 ng/g) and lindane (490 ng/g), loadings declined over a period of time, but it is perceived that contaminated sediments may pose a longer-term threat to benthic communities, particularly in the proximity of the spill site.     

Travel in a Different World Makes a World of Difference

By reference to the literature of postcolonial studies, this paper addresses some of the theoretical difficulties, paradoxes and contradictions that inhere in the study or teaching of ‘different’, that is, ‘non-Western’ architectures. It examines, in particular, the writings of Said on Orientalism, and those of Spivak and Homi Bhabha on the ‘unspeakability’ of the ‘different’ and ‘other.’ These writings call into question the possibility of an Orientalist scholarship or pedagogy that does not reinforce stereotypes and perpetuate unequal power relations. Taking these writings to their logical limit, they would seem to preclude in advance all attempts to introduce non-Eurocentric materials into the curricula of architectural schools, since this continues and strengthens neo-colonialist essentialising of otherness and difference. In response, it is suggested that this impasse can be avoided if the metaphors of confrontation, power and objectivity that ground critical theory in postcolonial studies are replaced by the hermeneutic metaphors of conversation, translation and travel. These metaphors indicate that the study of the architecture of the ‘different other’ can be included in the curriculum in ways that are not tainted by neo-colonialist attitude     

Settlement in Transition: a Transformation of a Village into a Small Town in Western Sudan

UN-Habitat projects Sub-Saharan Africa’s global share of the urban population to increase from 11.3% in 2010 to 20.2% by 2050. Yet little is documented about the underlying urbanization processes, particularly of emergence of small towns. This article uses household interviews, focus groups, observation, and secondary data to examine the spontaneous transformation of a western Sudanese village, Shubbola, into a small town. We use changes in building construction approach, materials, and style as an indicator of development and provide rare documentation of the process, the main actors, choices taken, timescales, and outcomes of the rapid urbanization of Shubbola between 2006 and 2013. Housing transformation was variable but involved a gradual process of replacing traditional non-durable building materials (wood and straw) with modern durable ones (sun- or fire-cured bricks, cement blocks, and metal roofs). Unlike traditional top-down models of urbanization generally driven by government investment, Shubbola epitomizes an organic, bottom-up process dependent on self-reliance and agriculture development fueled by remittances from urban-based relatives. While many small towns with similar origins fail to do so, Shubbola already provided important urban services to its inhabitants and surrounding rural areas. The study enhances understanding of small towns and underlying urbanization processes and their contribution to often neglected bottom-up, low-cost processes that do not fit traditional top-down models. It also contributes to literature and policy on sustainable cities and their role in sustainable development as encapsulated in UN Sustainable Development Goal 11. The study contributes to understanding the processes and implications of rapid urbanization in the Sudan and Africa and other world regions.     

Methods for the evaluation of a hinge pin in a clapper support of a check valve

Typical methods for the evaluation of a hinge pin used in a clapper support of a check valve are presented. For clarity, an example is provided to show the application of the equations.     

Long-term persistence of a nutrient-starved biofilm in a limestone fracture

The persistence of biofilms is a key element of the biobarrier concept applied to fractured rock. After a 43-day biostimulation with molasses for the biofilm growth (phase I), the effects of a 179-day starvation on the persistence of the biofilm (phase II) were investigated in a single-fractured limestone apparatus equipped to detect small changes in hydraulic conductivity (K) (cm min(-1)). The K in the central fracture section (Kf) decreased by 4.6 logs between days 0 and 167 and increased by 1.3 logs between days 167 and 222, leading to an overall 3.3-logs reduction for the 222-day experiment. Accumulation of rod- and filamentous-shaped bacteria and deposition of minerals were thought to account for the decrease in Kf. Even though the filamentous bacterial cells possibly enhanced the stability of the developing biofilm, increases in Kf became more frequent after 100 days of operation. This decrease in stability was presumably related to sloughing events, which were in turn attributed to a combination of processes, including nutrient deprivation, the release of deposited minerals, decreasing fluid flowrate, and endogenous decay as part of biofilm ageing. This study indicates that biofilms developed in fractures can persist for extended periods at reduced K when exposed to a long-term starvation.     

Selecting a suitable procurement method for a building project

Building procurement has become a fashionable term with industry practitioners and researchers. It determines the overall framework and structure of responsibilities and authorities for participants within the building process. It is a key factor contributing to overall client satisfaction and project success. The selection of the most suitable procurement method consequently is critical for both clients and project participants, and is becoming an important and contemporary issue within the building industry. The problem, nevertheless, lies in the fact that there has been limited empirical research in this field of study. Postal questionnaire surveys of 41 clients and 35 consultants were carried out, and were used to obtain experience of and attitudes to a variety of procurement methods and the criteria used for selection. The findings indicate that a simple set of the criteria generally is adequate and sufficient for procurement path selection, and that there is a reasonable consensus on the appropriate weighting for each path. Moreover, it is shown that, contrary to expectations, similar clients generally do not have similar procurement needs.     

Damage around a cylindrical opening in a brittle rock mass

This paper presents an application of the sliding/wing crack model to the problem of a cylindrical opening in a brittle rock mass subjected to a hydrostatic stress field. The rock mass is assumed to contain a uniform initial distribution of microcracks. These microcracks serve as sources of stress concentration, and can propagate tensile wing cracks at their tips in a compressive stress field. It is shown that the sliding/wing crack model can essentially reproduce the complex stress–strain response obtained in laboratory experiments. The stress and displacement field induced by excavation of a tunnel in such a brittle rock mass is determined using the Biot Hodograph Method. The condition for instability of the tunnel can be inferred from the wing crack density, which characterizes the degree of rock damage around the tunnel.