What Makes Educational Campaings Succeed?

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Polyimide processing additives

A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA

Measuring Transport Resilience: A Manawatu-Wanganui Region Case Study

The resilience of transport networks is attracting greater scrutiny at the international, national and sub-national levels. This research report explores the current state of knowledge about measuring transport resilience and presents a case study to address the question is: How resilient is the road and rail infrastructure in the Manawatu-Wanganui Region? This region in New Zealand’s lower North Island provides an interesting case study due to its strategic location in the North Island’s and indeed New Zealand’s transport network. In addition, it has experienced significant disruptions in the recent past, most notably widespread failures caused by flooding in 2004, and the lengthy closure of a significant inter-regional road connection, the Manawatu Gorge State Highway 3 road, due to a landslide in 2011-2012. It also provides an opportunity to explore this topic outside of a major metropolitan region. The region’s transport networks and infrastructure also have important social and economic functions. This research report is structured around a proposed Transport Resilience Indicator Framework (RIF) which explores six key dimensions of transport infrastructure resilience: engineering, services, ecological, social, economic and institutional. This holistic approach to measuring transport resilience and is envisaged to accommodate both qualitative and quantitative indicators. Within this framework, data were gathered via analysis of secondary sources and nine key informant interviews. The interview participants were from public sector agencies responsible for managing aspects of the region’s transport network, the private sector and one social service provider. The participants had considerable knowledge relating to the planning of the road network and/or its economic and social significance. They also had knowledge of the impacts and/or management of recent disruptions. The institutions responsible for managing the region’s transport network can identify vulnerabilities in the network, but can also collaborate and learn from past disruptions. Concerns were expressed about the level of funding for maintaining and upgrading the region’s transport networks, particularly for territorial authorities with large networks and small rates bases. The region is strongly dependent on the roading network, with limited alternatives during roading network disruptions. It proved difficult to quantify the environmental impacts of transport disruptions. A case study of the response of a local ii health shuttle service provided an example of how a community, by drawing on social capital, was able to adapt and respond appropriately to a transport disruption. One key area identified for further research is assessing the capacity of private contractors to respond to natural hazard events of varying magnitudes. The RIF could also be strengthened by the use of indicators based on quantitative data, in addition to qualitative data. It is suggested that one method of achieving this could this could be to adopt a multi-disciplinary approach, drawing on expertise, methods and perspectives from related professions, such as engineering and economics. [Executive summary

Yes, You Can Control Crabgrass!

A combination of cultural and chemical control practices works best in getting rid of this pest. Two new chemicals, in particular, show promise in preventing crabgrass seed germination and seedling establishment

Contact Atomic Structure and Electron Transport Through Molecules

Using benzene sandwiched between two Au leads as a model system, we investigate from first principles the change in molecular conductance caused by different atomic structures around the metal-molecule contact. Our motivation is the variable situations that may arise in break junction experiments; our approach is a combined density functional theory and Green function technique. We focus on effects caused by (1) the presence of an additional Au atom at the contact and (2) possible changes in the molecule-lead separation. The effects of contact atomic relaxation and two different lead orientations are fully considered. We find that the presence of an additional Au atom at each of the two contacts will increase the equilibrium conductance by up to two orders of magnitude regardless of either the lead orientation or different group-VI anchoring atoms. This is due to a LUMO-like resonance peak near the Fermi energy. In the non-equilibrium properties, the resonance peak manifests itself in a large negative differential conductance. We find that the dependence of the equilibrium conductance on the molecule-lead separation can be quite subtle: either very weak or very strong depending on the separation regime.Comment: 8 pages, 6 figure

Interaction-Induced Strong Localization in Quantum Dots

We argue that Coulomb blockade phenomena are a useful probe of the cross-over to strong correlation in quantum dots. Through calculations at low density using variational and diffusion quantum Monte Carlo (up to r_s ~ 55), we find that the addition energy shows a clear progression from features associated with shell structure to those caused by commensurability of a Wigner crystal. This cross-over (which occurs near r_s ~ 20 for spin-polarized electrons) is, then, a signature of interaction-driven localization. As the addition energy is directly measurable in Coulomb blockade conductance experiments, this provides a direct probe of localization in the low density electron gas.Comment: 4 pages, published version, revised discussio

Context-awareness for mobile sensing: a survey and future directions

The evolution of smartphones together with increasing computational power have empowered developers to create innovative context-aware applications for recognizing user related social and cognitive activities in any situation and at any location. The existence and awareness of the context provides the capability of being conscious of physical environments or situations around mobile device users. This allows network services to respond proactively and intelligently based on such awareness. The key idea behind context-aware applications is to encourage users to collect, analyze and share local sensory knowledge in the purpose for a large scale community use by creating a smart network. The desired network is capable of making autonomous logical decisions to actuate environmental objects, and also assist individuals. However, many open challenges remain, which are mostly arisen due to the middleware services provided in mobile devices have limited resources in terms of power, memory and bandwidth. Thus, it becomes critically important to study how the drawbacks can be elaborated and resolved, and at the same time better understand the opportunities for the research community to contribute to the context-awareness. To this end, this paper surveys the literature over the period of 1991-2014 from the emerging concepts to applications of context-awareness in mobile platforms by providing up-to-date research and future research directions. Moreover, it points out the challenges faced in this regard and enlighten them by proposing possible solutions

On the Distribution of a Second Class Particle in the Asymmetric Simple Exclusion Process

We give an exact expression for the distribution of the position X(t) of a single second class particle in the asymmetric simple exclusion process (ASEP) where initially the second class particle is located at the origin and the first class particles occupy the sites {1,2,...}

Enhancing the Mass Sensitivity of Graphene Nanoresonators Via Nonlinear Oscillations: The Effective Strain Mechanism

We perform classical molecular dynamics simulations to investigate the enhancement of the mass sensitivity and resonant frequency of graphene nanomechanical resonators that is achieved by driving them into the nonlinear oscillation regime. The mass sensitivity as measured by the resonant frequency shift is found to triple if the actuation energy is about 2.5 times the initial kinetic energy of the nanoresonator. The mechanism underlying the enhanced mass sensitivity is found to be the effective strain that is induced in the nanoresonator due to the nonlinear oscillations, where we obtain an analytic relationship between the induced effective strain and the actuation energy that is applied to the graphene nanoresonator. An important implication of this work is that there is no need for experimentalists to apply tensile strain to the resonators before actuation in order to enhance the mass sensitivity. Instead, enhanced mass sensitivity can be obtained by the far simpler technique of actuating nonlinear oscillations of an existing graphene nanoresonator.Comment: published versio

Search for Mars lander/rover/sample-return sites: A status review

Ten Mars sites were studied in the USA for four years. The sites are the Chasma Boreale (North Pole), Planum Australe (South Pole), Olympus Rupes, Mangala Valles, Memnonia Sulci, Candor Chasma, Kasel Valles, Nilosyrtis Mensae, Elysium Montes, and Apollinaris Patera. Seven sites are being studied by the USSR; their prime sites are located at the east mouth of Kasel Valles and near Uranius Patera. Thirteen geological maps of the first six USA sites are compiled and in review. Maps of the Mangala East and West sites at 1:1/2 million scale and a 1:2 million scale map show evidence of three episodes of small-channel formation interspersed with episodes of volcanism and tectonism that span the period from 3.5 to 0.6 b.y. ago. The tectonic and geological history of Mars, both ancient and modern, can be elucidated by sampling volcanic and fluvial geologic units at equatorial sites and layered deposits at polar sites. The evidence appears clear for multiple episodes of fluvial channeling, including some that are quite recent; this evidence contrasts with the theses of Baker and Partridge (1986) and many others that all channels are ancient. Verification of this hypothesis by Mars Observer will be an important step forward in the perception of the history of Mars