Space Weather Propagation in the Inner Heliosphere

The inner region of our solar system is vast, spanning hundreds of millions of kilometers and is driven by dynamics ranging in time scales from less than seconds to more than centuries. Space weather originating at the Sun and impacting life at Earth propagates through this complicated region, known as the inner heliosphere, whose dynamics is driven by the Sun’s dynamic magnetic field. When space weather such as interplanetary coronal mass ejections (ICMEs) impact Earth, they can induce geomagnetic storms which cause the aurorae, cause damage to satellites, cause radio and GPS interference, and induce ground currents which can damage power grid infrastructure. In order to accurately forecast space weather, we need to improve our ability to forecast space weather propagation through the inner heliosphere. To do so we need the ability to answer these two questions: “When observing space weather as far from the Sun as the Earth, how do we differentiate those features that are due to conditions near their origins at the Sun from those due to propagation effects as they traverse the inner heliosphere?” and “How do we then characterize those propagation effects to improve space weather predictions?” To address these questions this dissertation investigates three aspects of space weather propagation through the inner heliosphere: 1) How well do heavy ion charge distributions now-cast ICMEs at 1 AU? 2) How do arrival time, velocity and intensity of solar energetic electrons compare to modeled magnetic connectivity using ADAPT-WSA vs the Parker spiral? 3) How often are counterstreaming (CSEs) and strahl suprathermal electrons (SSEs) observed during in situ observations of ICMEs and what are their characteristics when compared to suprathermal electrons in the solar wind? In this thesis we analyze in situ observations of space weather to characterize features and quantify correlations which are due to interplanetary propagation effects versus those which are tied to properties near the Sun. We present this analysis and interpret the results in the context of space weather propagation to achieve significant progress in our understanding of the connection between the Sun and the near-Earth interplanetary environment. This will enable further study that can differentiate propagation effects from those of energization, acceleration and plasma conditions at the solar origins of these space weather events. Ultimately, this research will enhance our ability to forecast space weather propagation through the inner heliosphere.PHDClimate and Space Sciences and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/162882/1/aliciaks_1.pd

MULTIPLE PARTING SURFACES FOR SAND CASTING

ABSTRACT Multiple parting surfaces are frequently used in sand casting, die casting and injection molding processes. However, most research in this area has focused on die casting and injection molding. Parting surfaces for die casting and injection molding are relatively easier to compute compared to sand casting because their orientations and shapes are less restricted. In sand casting, the parting surfaces have to be parallel to each other and perfectly flat to permit the use of flasks with more than two pieces. The concepts of visibility and object illumination can be used to divide an object into two parts using a single parting surface. These methods, however, cannot be directly used for multiple parting surfaces. In this paper, a methodology to generate multiple parting surfaces for sand casting is described. The method uses Gauss maps to identify potential casting directions, and global accessibility cones to determine which faces can be cast in the same part of the pattern. The pattern is sliced using parallel planes such that each slice can be withdrawn from the mold in at least one direction. After the object is sliced, the number of parting surfaces is reduced by combining adjacent middle sections depending on their accessible directions

Interaction of High Aspect-Ratio Micro-Pillars with Wall Turbulence

An experimental study of the interaction between hairy structures modeled as high-aspect ratio micro-pillars (HAMuP) and wall turbulence is presented. Micro-pillars are elastic, hair-like microstructures which have been inspired by naturally occurring examples like lateral line sensors in fish and air flow sensors in bats. The objective of this thesis was two fold: to develop a manufacturing process for consistent production of HAMuP arrays, and to conduct a study focusing on the interaction of HAMuP arrays with wall turbulence. Hotwire anemometry measurements were carried out in two different experimental facilities at three different streamwise locations to describe the interaction between the HAMuP array and the wallturbulence. There is a shift of the laminar sublayer away from the wall indicated by a shift in the turbulent-intensity peak in the inner region of the flow over HAMuP array. The energy spectra also reveals a shift of the energetic structures away from the wall. Measurements taken downstream of the HAMuP array point to a damping of the energetic structures in the flow over the HAMuP array. The amplitude modulation coefficient is increased in the nearwall region which points to a possible mechanism by which the naturally occurring micro-pillars detect oncoming predators. A parametric approach was adopted to further study the effect of HAMuP arrays on turbulent boundary layer. The parameter study also reveals that a decrease in elastic modulus may lead to a decrease in the amount of energy the HAMuP arrays can extract from the flow. Also, increasing the height of the pillars might increase the potential elastic energy they can store but there is also a potential increase in the form drag due to the micro-pillars

Control of seagrass communities and sediment distribution by Callianassa (Crustacea, Thalassinidea) bioturbation

Shallow tropical lagoons at St. Croix, U.S. Virgin Islands were found to have high densities of the ghost shrimp Callianassa spp. The ecology of four species of Callianassa is discussed: C. acanthochirus, C. longiventris, C. rathbunae and C. quadracuta. The first two species capture and store in their burrows drifting detritus of seagrass and algae. The latter two species build volcano-shaped mounds of ejected sediment during feeding and burrowing. Massive quantities of sediment (up to 2.59 kg/m2/day) are funneled into subsurface galleries, gleaned for organic material and sorted. Fine grains (\u3c 1.4 mm diam.) are then pumped back up to the surface forming mounds. Coarse-grained material (≥ 1.4 mm) such as shell debris and coral fragments are not pumped back to the surface, but are stored in many deep chambers which extend \u3e 1.5 m below the sediment surface. In cross-section, cores from high Callianassa mound density regions show distinct alternating coarse and fine layers. This sedimentological evidence could be used as an indicator of Callianassa activity when interpreting the geological record from ancient tropical lagoonal environments.Maximum seagrass productivity and percent cover are negatively correlated (significant to p \u3c .01) with Callianassa mound density. Experimental and control transplants of the turtle grass Thalassia testudinum into regions of high (16/m2) and low (1/m2) Callianassa mound density produced a dramatic deterioration of Thalassia within 2-4 months in high density Callianassa areas. Ejected sediment either reduces available light for photosynthesis or physically smothers Thalassia, thereby eliminating it from regions of abundant Callianassa. Because seagrass communities have such intimate energetic ties to other nearby shallow-water and deep-sea communities, the negative influence of Callianassa on seagrass beds is suspected to have second and third order effects on other tropical communities as well

1996 Coolant Flow Management Workshop

The following compilation of documents includes a list of the 66 attendees, a copy of the viewgraphs presented, and a summary of the discussions held after each session at the 1996 Coolant Flow Management Workshop held at the Ohio Aerospace Institute, adjacent to the NASA Lewis Research Center, Cleveland, Ohio on December 12-13, 1996. The workshop was organized by H. Joseph Gladden and Steven A. Hippensteele of NASA Lewis Research Center. Participants in this workshop included Coolant Flow Management team members from NASA Lewis, their support service contractors, the turbine engine companies, and the universities. The participants were involved with research projects, contracts and grants relating to: (1) details of turbine internal passages, (2) computational film cooling capabilities, and (3) the effects of heat transfer on both sides. The purpose of the workshop was to assemble the team members, along with others who work in gas turbine cooling research, to discuss needed research and recommend approaches that can be incorporated into the Center's Coolant Flow Management program. The workshop was divided into three sessions: (1) Internal Coolant Passage Presentations, (2) Film Cooling Presentations, and (3) Coolant Flow Integration and Optimization. Following each session there was a group discussion period

Geometric aspects of the casting process

Manufacturing is the process of converting raw materials into useful products. Among the most important manufacturing processes, casting is a commonly used manufacturing process for plastic and metal objects. The industrial casting process consists of two stages. First, liquid is filled into a cavity formed by two cast parts. After the liquid has hardened, one cast part retracts, carrying the object with it. Afterwards, the object is ejected from the retracted cast part. In both retraction and ejection steps, the cast parts and the object should not be damaged, so that the quality of final object is guaranteed and the cast parts can be reused to produce another object. This mode of production is called ``mass production''. Due to the geometric nature of the casting process, many geometric problems arise in the automation of casting. The problems we address here concern this aspect: Given a 3-dimensional object, is there a cast for it whose parts can be removed after the liquid has solidified? An object for which this is the case is called castable. We consider the castability problem in three different casting models with a two-part cast. In the first casting model, two parts must be removed in opposite directions. There are two cases depending on whether the removal direction is specified in advance or not. The second model is identical to the first casting model, except that the cast machinery has a certain level of uncertainty in its directional movement. In the third model, the two cast parts are to be removed in two given directions and these directions need not be opposite. For all three casting models, we give complete characterizations of castability, and obtain algorithms to verify these conditions for polyhedral parts. In manufacturing, features of an object imply manufacturing information, which facilitates the process of analyzing manufacturability and the automated design of a cast for the object. A small hole or a depression on the boundary of an object, for example, restricts the set of removal directions for which this object is castable, since the portion of the cast in the hole or in the depression must be removed from the object without breaking the object. We define a geometric feature, the cavity, which is related to the castability of objects, and provide algorithms to extract it from objects

Rotating heat transfer measurements on a multi-pass internal cooling channel - II experimental tests

The present contribution describes the design and realization of a rotating test rig for heat transfer measurements on internal cooling passages of gas turbine blades. The aim is to study the effects of Coriolis and buoyancy forces on the heat transfer distribution inside realistic cooling schemes. Spatially resolved heat transfer data are obtained by means of transient thermo-chromic liquid crystals (TLC) technique. In order to replicate the same buoyancy effects induced by the Coriolis forces during rotation, the transient measurements are performed with a cold temperature step on the coolant flow. New solutions are adopted to generate the cold temperature step, acquire the experimental data on board of the rotating test model and to control the experimental parameters during tests execution. The main components of the rig will be described in the paper, together with an overview of the data processing methodology that has been developed

Impaired high-density lipoprotein function in patients with heart failure

Background: We recently showed that, in patients with heart failure, lower high‐density lipoprotein (HDL) cholesterol concentration was a strong predictor of death or hospitalization for heart failure. In a follow‐up study, we suggested that this association could be partly explained by HDL proteome composition. However, whether the emerging concept of HDL function contributes to the prognosis of patients with heart failure has not been addressed. Methods and Results: We measured 3 key protective HDL function metrics, namely, cholesterol efflux, antioxidative capacity, and anti‐inflammatory capacity, at baseline and after 9 months in 446 randomly selected patients with heart failure from BIOSTAT‐CHF (A Systems Biology Study to Tailored Treatment in Chronic Heart Failure). Additionally, the relationship between HDL functionality and HDL proteome composition was determined in 86 patients with heart failure. From baseline to 9 months, HDL cholesterol concentrations were unchanged, but HDL cholesterol efflux and anti‐inflammatory capacity declined (both P<0.001). In contrast, antioxidative capacity increased (P<0.001). Higher HDL cholesterol efflux was associated with lower mortality after adjusting for BIOSTAT‐CHF risk models and log HDL cholesterol (hazard ratio, 0.81; 95% CI, 0.71–0.92; P=0.001). Other functionality measures were not associated with outcome. Several HDL proteins correlated with HDL functionality, mainly with cholesterol efflux. Apolipoprotein A1 emerged as the main protein associated with all 3 HDL functionality measures. Conclusions: Better HDL cholesterol efflux at baseline was associated with lower mortality during follow‐up, independent of HDL cholesterol. HDL cholesterol efflux and anti‐inflammatory capacity declined during follow‐up in patients with heart failure. Measures of HDL function may provide clinical information in addition to HDL cholesterol concentration in patients with heart failure