title: Mixed signal approach for rapid prototyping of a compact smart pebble for sediment transport monitoring in river beds

authors: Kularatna, Nihal

subjects: MEMS

abstract: Low-cost accelerometers and gyro ICs were used to develop a smart sediment particle to study the sediment transport in rivers. With strap-down MEMS, battery, a processing subsystem and memory, this self contained unit captures semiprocessed data for durations up to 15 minutes. In a mixed-mode design, analog multiplier ICs with limited digital circuits transform the body frame data to a reference frame using Euler angles, with adequate accuracy despite cumulative errors. For 3D motion, up to nine sensor inputs from three orthogonal modules are coupled to a multiplexed analog processing module, and processed by a digital module for data conversion and storage. Despite the simplified mathematics used, experimental data from the proof-of-concept system provided adequate accuracy. Subsequent processing of the raw sensor data using an external PC program with smart algorithms allowed the comparison of accuracy of the mixed mode approach. The adopted mixed signal design approach helps the packaging requirements due to the specific nature of the problem with short recording durations.

text: Mixed signal approach for rapid prototyping of a compact smart pebble for sediment transport monitoring in river beds Low-cost accelerometers and gyro ICs were used to develop a smart sediment particle to study the sediment transport in rivers. With strap-down MEMS, battery, a processing subsystem and memory, this self contained unit captures semiprocessed data for durations up to 15 minutes. In a mixed-mode design, analog multiplier ICs with limited digital circuits transform the body frame data to a reference frame using Euler angles, with adequate accuracy despite cumulative errors. For 3D motion, up to nine sensor inputs from three orthogonal modules are coupled to a multiplexed analog processing module, and processed by a digital module for data conversion and storage. Despite the simplified mathematics used, experimental data from the proof-of-concept system provided adequate accuracy. Subsequent processing of the raw sensor data using an external PC program with smart algorithms allowed the comparison of accuracy of the mixed mode approach. The adopted mixed signal design approach helps the packaging requirements due to the specific nature of the problem with short recording durations.

year: 2005

title: A turbulence-driven model for heating and acceleration of the fastwind in coronal holes

authors: Verdini, A.

subjects: MHD

abstract: A model is presented for generation of fast solar wind in coronal holes, relying on heating that is dominated by turbulent dissipation of MHD fluctuations transported upward in the solar atmosphere. Scale-separated transport equations include large-scale fields, transverse Alfvénic fluctuations, and a small compressive dissipation due to parallel shears near the transition region. The model accounts for proton temperature, density, wind speed, and fluctuation amplitude as observed in remote sensing and in situ satellite data.

text: A turbulence-driven model for heating and acceleration of the fastwind in coronal holes A model is presented for generation of fast solar wind in coronal holes, relying on heating that is dominated by turbulent dissipation of MHD fluctuations transported upward in the solar atmosphere. Scale-separated transport equations include large-scale fields, transverse Alfvénic fluctuations, and a small compressive dissipation due to parallel shears near the transition region. The model accounts for proton temperature, density, wind speed, and fluctuation amplitude as observed in remote sensing and in situ satellite data.

year: 2010

title: Food insecurity in urban New Zealand. The case of the Kopa family

authors: Graham, Rebekah Sarah

abstract: Poverty brings insecurity and chaos into the home, forcing families to develop strategies for navigating the difficulties of food insecurity. We document how one household, the Kopa family, responds to poverty in ad hoc and agentive ways that assist and hinder their attempts to keep themselves fed. This study is based on a series of eight qualitative interviews with family members, including photo-elicitation and go-along techniques, as well as extensive field notes from more casual research interactions such as shared meals. Our analysis demonstrates how food insecurity shapes this family’s culturally patterned social practices surrounding the procurement, consumption, and sharing of food.

text: Food insecurity in urban New Zealand. The case of the Kopa family Poverty brings insecurity and chaos into the home, forcing families to develop strategies for navigating the difficulties of food insecurity. We document how one household, the Kopa family, responds to poverty in ad hoc and agentive ways that assist and hinder their attempts to keep themselves fed. This study is based on a series of eight qualitative interviews with family members, including photo-elicitation and go-along techniques, as well as extensive field notes from more casual research interactions such as shared meals. Our analysis demonstrates how food insecurity shapes this family’s culturally patterned social practices surrounding the procurement, consumption, and sharing of food.

year: 2018