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Groundwater Interaction and Surface Water Impacts on the Ground- Coupled Geothermal Heat Exchanger at Carleton College
No full textGround-coupled closed-loop geothermal heat exchangers are highly efficient alternatives to fossil fuels to reduce emissions for building heating and cooling systems. Implementing geothermal heat exchangers increases efficiency when deployed at a district scale, but risks altering the geochemistry of the groundwater due to elevated subsurface temperature. In 2018, Carleton College (Northfield, MN) installed a district-scale closed-loop geothermal heat exchanger with 95 horizontal 155 m long bores beneath Ordovician sedimentary rocks. The temperature of groundwater was measured in 5 observation wells installed between the edge of the borefield and Spring Creek—a small deep-aquifer-sourced spring-fed tributary of the Cannon River that runs around the perimeter of the borefield. The temperature of the creek was recorded to distinguish the thermal inputs from springs, and potential infiltration from shallow geothermally heated groundwater flowing from the borefield. Clear heat signatures from the heat exchanger in Spring Creek indicate substantive groundwater flow, consistent with prior studies at Carleton. However, spring inputs mitigate the heating and cooling effects on creek temperature by the heat exchanger. Consequently, the resulting creek temperature profile does not appear to have an environmentally concerning temperature change. Groundwater temperature does increase downstream of the borefield, but groundwater flow is rapid enough to avoid thermal buildup across seasons. Further monitoring is required to evaluate if the subsurface groundwater temperature increases on an annual basis
Asymmetrical Horizontal Gene Transfer Between Parasites and Hosts: Evolutionary Constraints and Functional Implications
No full textU & I in the classroom: Leveraging interdisciplinary research in educational technology interface design
No full textEducational technology in the classroom has benefits and drawbacks. Students can benefit from the individualization of their learning progress and the accessibility of information. However, students can easily become distracted, rely on the technology rather than struggling through new information on their own, and be more affected by individual differences that set students apart. To better design educational technology, interface designers must collaborate with other experts in the fields of education, educational psychology, and cognitive psychology. The design of future interfaces would benefit from prioritizing (1) designing for the unique situation of the student as a user, (2) emphasizing technology as a tool to support learning, and (3) exploiting known cognitive processes to get the most out of an interface. One individual discipline cannot accomplish this design on its own and must rely on other experts to make a positive impact on students and their education. Together, future interface design of educational technology can work towards being beneficial and limiting the negative impacts of technology in the classroom
Constantine’s Cults: Interconnected Iconographies of Religion and Power in the Roman Empire
No full textA Systematic Review of Visual Competition Effects in the Visual World Paradigm
No full textThe visual world paradigm (VWP) is a commonly-used method for studying speech processing. The VWP involves participants looking at an array of objects and tracking their eye movements as they listen to speech. Visual competition effects—a specific finding identified using the VWP—describe the tendency for participants to fixate on visually similar objects to those mentioned in the audio. There has been little metanalytic work examining the methodology of VWP studies, despite recent evidence that common differences in study design and analysis can greatly affect outcomes. The current paper assessed visual similarity coding, preview time selection, and analysis time window selection and found that methodological decisions of the literature had an overall lack of consistency and several instances of practices that might impede proper interpretation of results. Future VWP research on visual competitors should consider using validated visual stimuli, alternative methods of statistical analysis that don’t require specific time windows and provide additional justification for methodological decisions. Future research should also attempt to resolve the lack of clarity regarding the theoretical background behind the VWP
Unraveling the Physics Behind Digital Photography
No full textDigital photography has entirely changed the way we gather information about the world around us. In this paper, we examine the physical processes that occur when a photo is captured and explore the various models that enable us to design and characterize digital cameras. We begin by discussing the wave and particle models of light and considering their respective applications. Next, we introduce ray optics and Fourier optics to develop two complementary models for imaging systems. Finally, we focus on the science behind complementary metal oxide semiconductor (CMOS) array detectors, which facilitate rapid and efficient digitization of optical images. By discussing the harmonious interaction between diverse models and subfields, we aim to offer insights into how physics has contributed to the remarkable advancements in digital imaging capabilities
Hunting for Home: Placemaking Through the Deer Harvest in Non-Indigenous Northern Southeast Alaskan Communities
No full textSitka black-tailed deer harvest is a focal point in the lives of many in Southeast Alaska. Along with other subsistence practices that settler communities value, hunting is a uniquely potent anchor for a sense of belonging. Within placemaking literature practices like this are commonly articulated as the source of socio-ecological meaning, yet the processes that spark its creation are underexplored. Through an ethnographic study of deer hunting, I propose an alternate placemaking model as an active and rapid process where potency is defined not by cultural breadth but by depth and intensity. Through story-based methodologies, I show the material and emotional aspects of the harvest that catalyze an explicitly spiritual realm, essential to hunters\u27 identity in times of precarity. The constant of the deer harvest, through people’s calendars, families, and sense of self is unique, isolated, and an almost instantaneous cultural force for those who encounter it. The resulting view of placemaking - with room for the sporadic, poignant and dynamic - is critical to articulate and interrogate emotional stakeholders within modern tumultuous place and human relationships
Linux Privilege Escalation and Vulnerability Exploit Script (linPEVES)
No full textA tool that scans for and exploits privilege escalation (PE) vulnerabilities within a Linux machine, made in the style of linPEAS. Our suite of custom scans facilitate the exploitation of each respective vulnerability, if found
Interactions between Limestone, Shale, and Sandstone Aggregates and Acid Mine Drainage (AMD)
No full textCrushed samples of limestone, two types of shale, and sandstone were exposed to acid mine drainage (AMD) collected at the Bear Valley Strip Mine in Northumberland County, PA. Roughly 40g of each type of rock was left separately submerged for 166 hours in 200mL of AMD and stirred using magnetic stir bars to create flow. Over the course of the experiment the pH of AMD in the beakers with limestone or shale increased from 3.86 to 7 or 8, while the pH of AMD in the beaker with sandstone remained close to 4. Visible precipitates appeared to form in most beakers. The results were affected by significant evaporation which occurred in all beakers but disproportionately impacted the beaker containing sandstone. X-ray fluorescence (XRF) analysis of the crushed rock samples before and after the experiment was conducted, and major cation concentrations in the AMD were measured via inductively coupled plasma (ICP) mass spectroscopy. Comparison between XRF and ICP results indicated that XRF measurement uncertainty likely completely precluded definitive conclusions about the identity of the precipitates that formed. Major cation concentrations in the AMD tended to increase over the duration of the experiment due to low initial concentrations in the field samples
Seeing the Unseen: Signal Processing and Electronic Beam Steering in RADAR
No full textRadio detecting and ranging devices provide us with a method to understand the world beyond the limited field of our vision. They operate by transmitting radio waves and analyzing the reflected signals to determine the position, velocity, and characteristics of distant objects. This paper will provide an overview of electromagnetic wave properties and demonstrate how they can be manipulated in radar systems. It will then develop the necessary tools to understand how a digital signal is processed in a system. This will include an overview of Fourier approximations for periodic and aperiodic signals. Finally, the paper will discuss how radar beams are directed and the properties of wave scattering that make an object detectable by radar