User perceptions and practical considerations for implementation of advanced sanitation technologies: a case study of the nano membrane toilet from Kumasi, Ghana

In response to the growing need for sustainable urban sanitation, technologies are being developed that will be completely novel to their target context. The successful adoption of such technologies will be dependent on their acceptability to end users and their adaptability to local settings. As part of the development of the Nano Membrane toilet, a design team conducted a field study in Kumasi, Ghana, to gauge acceptability of the design and to assess the perceived value of the designed outputs of the toilet. In addition, a physical survey was conducted of the residences of the interviews. Overall, the surveys provided information about site-specific attitudes and physical limitations which would need to be considered by designers. These types of survey can be used by technology developers to assist design or to identify areas that are appropriate for their technology. Conversely, similar surveys could be used as a community assessment tool to identify technologies that are best adapted for a specific circumstance

User perspectives to direct water reuse from the Nano Membrane toilet

The Nano Membrane toilet is a response to the Bill and Melinda Gates Foundation ‘Re-invent the Toilet Challenge’. The Nano Membrane toilet has many design aspects that will involve interaction by the end-user, including water reuse from the membrane treatment system which produces treated water directly available to the user at household level. In order to maintain a user focused design development, a survey was carried out on potential end users in Kumasi, Ghana, in order to understand their attitudes to direct reuse of water from the toilet, and how the attitudes may be affected by aesthetic changes to the water. It was found that end users would be willing to use the product water for a wide range of household purposes, with cleaning being the most likely. Odour was found to have the greatest effect over taste and colour on user’s willingness for all potential purposes, including drinking, cooking, and teeth cleaning

An Overview of Advanced Elastomeric Seal Development and Testing Capabilities at NASA Glenn Research Center

NASA is developing advanced space-rated elastomeric seals to support future space exploration missions to low Earth orbit, the Moon, near Earth asteroids, and other destinations. This includes seals for a new docking system and vehicle hatches. These seals must exhibit extremely low leak rates to ensure that astronauts have sufficient breathable air for extended missions. Seal compression loads must be below prescribed limits so as not to overload the mechanisms that compress them, and seal adhesion forces must be low to allow the sealed interface to be separated when required (e.g., during undocking or hatch opening). NASA Glenn Research Center has developed a number of unique test fixtures to measure the leak rates and compression and adhesion loads of candidate seal designs under simulated thermal, vacuum, and engagement conditions. Tests can be performed on full-scale seals with diameters on the order of 50 in., subscale seals that are about 12 in. in diameter, and smaller specimens such as O-rings. Test conditions include temperatures ranging from -238 to +662F (-150 to +350C), operational pressure gradients, and seal-on-seal or seal-on-flange mating configurations. Nominal and off-nominal conditions (e.g., incomplete seal compression) can also be simulated. This paper describes the main design features and capabilities of each test apparatus and provides an overview of advanced seal development activities at NASA Glenn

Social and economic factors influencing the choice of water supply in rural Karnataka, India

India is an enormously diverse country, although the challenges of water scarcity and quality are almost ubiquitous. This paper focuses on two villages in Karnataka state where a mixed methods qualitative research approach was applied. This revealed that decision - making about water supplies was made in a top-down fashion and there was little opportunity for village members to contribute. The policies and tariff systems were extremely complex. Communities had their own social and religious beliefs about their water supplies as well. Together these may be contributing to their rejection of the government supplied water and their use of alternative, often unimproved sources and of water filters in their houses. These decisions and the reasons behind them will be further explored in an additional fieldwork campaign

Time-distance analysis of the emerging active region NOAA 10790

We investigate the emergence of Active Region NOAA 10790 by means of time – distance helioseismology. Shallow regions of increased sound speed at the location of increased magnetic activity are observed, with regions becoming deeper at the locations of sunspot pores. We also see a long-lasting region of decreased sound speed located underneath the region of the flux emergence, possibly relating to a temperature perturbation due to magnetic quenching of eddy diffusivity, or to a dense flux tube. We detect and track an object in the subsurface layers of the Sun characterised by increased sound speed which could be related to emerging magnetic-flux and thus obtain a provisional estimate of the speed of emergence of around 1 km s−1

How to Test Stringy Dark Energy?

It is suggested, by using a covariant lagrangian formalism to estimate the equation of state $w = p/\rho$, that stringy dark energy predicts $w < -1$, a negative pressure larger in magnitude than that for a cosmological constant or quintessence. This would lead to a later transition from decelerating to accelerating cosmological expansion; $w = - 4/3$ is briefly considered as one illustrative example.Comment: 4 pages LaTeX. v2. Typos correcte

Solar Polar Fields During Cycles 21 --- 23: Correlation with Meridional Flows

We have examined polar magnetic fields for the last three solar cycles, {$\it{viz.}$}, cycles 21, 22 and 23 using NSO Kitt Peak synoptic magnetograms. In addition, we have used SoHO/MDI magnetograms to derive the polar fields during cycle 23. Both Kitt Peak and MDI data at high latitudes (78${^{\circ}}$--90${^{\circ}}$) in both solar hemispheres show a significant drop in the absolute value of polar fields from the late declining phase of the solar cycle 22 to the maximum of the solar cycle 23. We find that long term changes in the absolute value of the polar field, in cycle 23, is well correlated with changes in meridional flow speeds that have been reported recently. We discuss the implication of this in influencing the extremely prolonged minimum experienced at the start of the current cycle 24 and in forecasting the behaviour of future solar cycles.Comment: 4 Figures 11 pages; Revised version under review in Solar Physic

Coupled oscillators as models of phantom and scalar field cosmologies

We study a toy model for phantom cosmology recently introduced in the literature and consisting of two oscillators, one of which carries negative kinetic energy. The results are compared with the exact phase space picture obtained for similar dynamical systems describing, respectively, a massive canonical scalar field conformally coupled to the spacetime curvature, and a conformally coupled massive phantom. Finally, the dynamical system describing exactly a minimally coupled phantom is studied and compared with the toy model.Comment: 18 pages, LaTeX, to appear in Physical Review

Comment on "Resolving the 180-deg Ambiguity in Solar Vector Magnetic Field Data: Evaluating the Effects of Noise, Spatial Resolution, and Method Assumptions"

In a recent paper, Leka at al. (Solar Phys. 260, 83, 2009)constructed a synthetic vector magnetogram representing a three-dimensional magnetic structure defined only within a fraction of an arcsec in height. They rebinned the magnetogram to simulate conditions of limited spatial resolution and then compared the results of various azimuth disambiguation methods on the resampled data. Methods relying on the physical calculation of potential and/or non-potential magnetic fields failed in nearly the same, extended parts of the field of view and Leka et al. (2009) attributed these failures to the limited spatial resolution. This study shows that the failure of these methods is not due to the limited spatial resolution but due to the narrowly defined test data. Such narrow magnetic structures are not realistic in the real Sun. Physics-based disambiguation methods, adapted for solar magnetic fields extending to infinity, are not designed to handle such data; hence, they could only fail this test. I demonstrate how an appropriate limited-resolution disambiguation test can be performed by constructing a synthetic vector magnetogram very similar to that of Leka et al. (2009) but representing a structure defined in the semi-infinite space above the solar photosphere. For this magnetogram I find that even a simple potential-field disambiguation method manages to resolve the ambiguity very successfully, regardless of limited spatial resolution. Therefore, despite the conclusions of Leka et al. (2009), a proper limited-spatial-resolution test of azimuth disambiguation methods is yet to be performed in order to identify the best ideas and algorithms.Comment: Solar Physics, in press (19 pp., 5 figures, 2 tables

Testing decentralised treatment solutions for portable home toilet waste - Kumasi, Ghana

Water and Sanitation for the Urban Poor (WSUP) and Unilever have developed Clean Team, a business providing portable home toilets that are attractive and branded. Customers pay for their waste to be collected two to four times per week. Three “off-the-shelf” technologies are being tested to treat this waste and allow Clean Team to scale up to other cities. The three technologies are Sistema Biobolsa, which uses flexible tubes as anaerobic digesters, and aerobic planted gravel filter; Biorock, where an anaerobic pre-treatment tank is followed by an aerobic tank containing synthetic filtration media, pretreated with enzymes that stimulate the growth of aerobic bacteria and ventilation executed by natural draft; and Biofil, which will receive the sludge from the Biorock system, and digest it using macrofauna. The paper will present the initial trial results