• Interferometric modification of the Lockheed Martin PSTAR system to facilitate three dimensional airspace surveillance

      Otterbacher, Scott E. (2011-05)
      The Lockheed Martin PSTAR is a monostatic radar system that provides range, azimuth, and radial velocity information of detected targets. While this system is useful for airspace surveillance in remote locations due to its portability and durability, it lacks the ability to record target information and the ability to estimate target elevation angle, resulting in a vertical arc of possible target locations. Due to a desire to use the PSTAR for applications that require logging three-dimensional target information, a spatial interferometric modification has been implemented. The PSTAR estimates range from pulse propagation delay and azimuth angle from the orientation of the antenna on a rotating pedestal. Two PSTAR antennas were removed from their housings and mounted, vertically separated, in a custom enclosure allowing for the estimation of elevation angle through spatial interferometry. The reflected signal is received by both antennas, mixed to baseband, and then the two pairs of I/Q channels are simultaneously sampled at 1 MS/s. Target elevation angle is estimated by determining the phase difference of the target's reflection received by the two vertically spaced antennas. Range, azimuth, and radial velocity are also estimated. All data collection was implemented in LabVIEW and data post-processing was implemented in MATLAB.
    • Intermittent hypercapnia induces long-lasting ventilatory plasticity to enhance CO₂ responsiveness to overcome dysfunction

      Mosher, Bryan Patrick; Harris, Michael B.; Taylor, Barbara E.; Hueffer, Karsten; Edmonds, Brian W. (2014-05)
      The ability of the brain to detect (central CO₂ chemosensitivity) and respond to (central CO₂ chemoresponsiveness) changes in tissue CO₂/pH, is a homeostatic process essential for mammalian life. Dysfunction of the serotonin (5-HT) mechanisms compromises ventilator CO₂ chemosensitivity/responsiveness and may enhance vulnerability to pathologies such as the Sudden Infant Death Syndrome (SIDS). The laboratory of Dr. Michael Harris has shown medullary raphe' contributions to central chemosensitivity involving both 5-HT- and y-aminobutyric acid (GABA)-mediated mechanisms. I tested the hypothesis that postnatal exposure to mild intermittent hypercapnia (IHc) induces respiratory plasticity, due in part to strengthening of bicuculline- and saclofen-sensitive mechanisms (GABAA and GABAB receptor antagonists respectively). Rats were exposed to IHc-pretreatment (8 cycles of 5 % CO₂) for 5 days beginning at postnatal day 12 (P12). I subsequently assessed CO₂ responsiveness using an in situ perfused brainstem preparation. Hypercapnic responses were determined with and without pharmacological manipulation. In addition, IHc-pretreatment effectiveness was tested for its ability to overcome dysfunction in the CO₂ responsiveness induced by a dietary tryptophan restriction. This dysfunctional CO₂ responsiveness has been suggested to arise from a chronic, partial 5-HT reduction imparted by the dietary restriction. Results show IHc-pretreatment induced plasticity sufficient for CO₂ responsiveness despite removal of otherwise critical ketanserin-sensitive mechanisms. CO₂ responsiveness following IHc-pretreatment was absent if ketanserin was combined with bicuculline and saclofen, indicating that the plasticity was dependent upon bicuculline- and saclofen-sensitive mechanisms. IHc-induced plasticity was also capable of overcoming the ventilatory defects associated with maternal dietary restriction. Duration of IHc-induced plasticity was also investigated and found to last far into life (up to P65). Furthermore, I performed experiments to investigate if IHc-induced plasticity was more robust at a specific developmental period. No such critical period was identified as IHc-pretreatment induced robust respiratory plasticity when administered at all developmental periods tested (P12-16, P21-25 and P36-40). I propose that IHc-induced plasticity may be able to reduce the severity of reflex dysfunctions underlying pathologies such as SIDS.
    • International and domestic drivers of military shifts in Alaska

      Burkhart, Peter K.; Boylan, Brandon M.; Ehrlander, Mary F.; Speight, Jeremy S. (2018-05)
      Since WWII, Alaska has witnessed dramatic influxes and reductions in military personnel and funding. This thesis explores the drivers of these events. It applies two theories to analyze the trends: realist theory from international relations and the advocacy coalition framework from public policy. The thesis uses a case study framework and process-tracing to analyze three different time periods in Alaska's history: 1) World War II (1940-1945), 2) the early Cold War era (1950-1958), and 3) the immediate post-Cold War era (1993-1999). This thesis argues that the level of international threat accounts for the United States' decisions to increase or decrease its military forces, while the strength of advocacy coalitions comprised of a diverse array of actors determines the amount of military personnel and funding transferred to Alaska.
    • Internet based data collection and monitoring for wireless sensor networks

      Revuri, Venkatramana Reddy (2007-05)
      The omnipresence of the Internet and the advances in integrated circuit technologies has expanded the potential modes of communication and data collection. Adding Internet capabilities to any electronic device greatly extends the device's user interface, allowing the user to remotely configure and monitor the device over the network through the embedded web server. The embedded web server is expected to establish two-way communication and serve dynamic web pages using very limited resources. We adapted an existing embedded web server to allow remote control and monitoring of wireless sensor networks (WSN). This required establishing an interface to the WSN and developing firmware and user programs to communicate with the remote client. An interactive and flexible web-based user management interface is developed to allow the two-way interaction between the remote user and the wireless sensor network. The embedded server generates email alerts to the administrator about critical issues in the WSN, provides secure access to the WSN control modules, etc. Two embedded web servers are developed using different hardware platforms. The first solution is a low cost, energy efficient solution with somewhat limited functionality. The other uses a more powerful microcontroller-based platform and implements a fully-functional, dynamic web server with multiple web pages.
    • Interpretation of radarsat SAR scenes of Sagwon Alaska, to establish temporal, spatial and physical active layer behavior

      Lovick, Joseph Thomas (2003-05)
      Radarsat SAR images of the Kuparuk Basin in North Alaska can be used to describe the timing and characteristics of the seasonal freeze-thaw cycle and the spatial distribution of two types of Arctic Tundra. The freezing of the ground surface; decreases backscatter brightness by 3dB allowing the date of freeze-up and thaw to be established. Using Empirical Orthogonal Functions on amplitude images allows the subtle change in the brightness (during winter) of different tundra types to be enhanced, which provides a technique for discriminating between areas of Moist Acidic Tundra and Moist Non-acidic Tundra. The sand to clay ratio affects the backscatter properties of frozen soil and is inferred to cause this brightness difference. Coherence images show the dynamic nature of Arctic tundra, and low coherence limits the applicability of interferometric techniques to describe active layer heave, however, preliminary results show promise in the application of a differential interferometric technique.
    • Interpreters perspective on intercultural communication

      Seyidova, Gulchin F. (2007-05)
      Although Translation/Interpreting Studies and Intercultural Communication Studies appear to be closely related fields of studies, both seem to have ignored their potential connectedness. In Interpreting Studies, scholars and practitioners have begun to recognize that interpreters have intercultural communication functions and do not simply automatically convey messages across parties. In Intercultural Communication Studies, scholars have neglected examining intercultural communication in the interpreting context. This study explores professional Azerbaijani interpreters' lived experiences of intercultural challenges they face in the interpreting setting to help better understand both the communication processes involved in interpreting, and interpreting as a scene for intercultural communication. Conversational interviews were employed to access lived human experiences of the researcher and the co-researchers, and thematic analysis of the capta revealed four broad themes regarding intercultural challenges encountered by interpreters during interpreting: 'the interpreter is not a robot, ' 'the interpreter has her/his sex, religion, and culture, ' 'the interpreter is between two cultures, ' and 'it depends.' These themes are intertwined and point to the conclusion that cultural difference should not be ignored in the interpreting setting.
    • Interrelationship among temperature, metabolism, swimming performance and recovery in Pacific cod (Gadus macrocephalus): implications of a changing climate

      Hanna, Shannon K. (2006-12)
      Physiological constraints are suggested to contribute to the observed changes in relative abundance of Pacific cod (Gadus macrocephalus) seen in association with interdecadal changes in sea surface temperatures. To examine this concept, two experiments were conducted to determine critical swimming speed (Ucrit), rates of oxygen consumption and recovery post-exhaustion of adult cod acclimated to different temperatures. In addition, hematocrit and plasma concentrations of cortisol, metabolites and ions from resting and exhausted fish were measured to assess the impact of swim trials on fish condition. In experiment one, fish acclimated to 4°C had similar mean Ucrit (1.07 BL/s) and resting metabolic rates (35.34 mg O₂/kg⁰⁸/hr) compared to fish acclimated to 11°C fish (1.07 BL/s; 49.43 mg O₂/kg⁰⁸/hr). Similarly, concentrations of blood constituents differed little between temperature treatments; each exhibited increases in plasma cortisol and metabolites from pre- to post-swim. Experiment two illustrated few differences in rates of recovery between temperature groups (2 and 7°C). After four hours of recovery there was no evidence of plasma cortisol or metabolites returning to pre-swim concentrations in either temperature group. It seems unlikely that physiological constraints on the metabolic performance of adult Pacific cod contribute to changes in their relative abundance.
    • Interrelationships of Pacific herring, Clupea pallasi, populations and their relation to large-scale environmental and oceanographic variables

      Williams, Erik Hamilton; Quinn, T. II (1999)
      Recruitment estimates for Pacific herring, Clupea pallasi, populations in the Bering Sea and Northeast Pacific Ocean are highly variable, difficult to forecast, and crucial for determining optimum harvest levels. Age-structured population models for annual stock assessments of the sac-roe fisheries rely on fishery and survey age composition data tuned to an auxiliary survey of total biomass. In Chapter 1, the first age-structured model for Norton Sound herring was developed similarly to existing models. Estimates of variability from age-structured stock assessment models for Pacific herring are often not calculated. In Chapter 2, a parametric bootstrap procedure using a fit of the Dirichlet distribution to observed age composition data was developed as a quick and easy method for computing error estimates of model estimates. This bootstrap technique was able to capture variability beyond that of the multinomial distribution. This technique can provide estimates of variability for existing population models with age composition data requiring little change to the original model structure. Recruitment time series from Pacific herring stock assessment models for 14 populations in the Bering Sea and Northeast Pacific Ocean were analyzed for links to the environment. For some populations, recruitment series were extended backward in time using cohort analysis. In chapter 3, correlation and multivariate cluster analyses were applied to determine herring population associations. There appear to be four major herring groups: Bering Sea, outer Gulf of Alaska, coastal SE Alaska, and British Columbia. These associations were combined with an exploratory correlation analysis of environmental data in chapter 4. Appropriate time periods for environmental variables were determined for use in Ricker type environmentally dependent spawner-recruit forecasting models. Global and local scale environmental variables were examined in forecasting models, resulting in improvements in recruitment forecasts compared to models without environmental data. The exploratory correlation analysis and best fit models, determined by jackknife error prediction, indicated temperature data corresponding to the year of spawning resulted in the best forecasting models. The Norton Sound age-structured model, parametric bootstrap procedure, and recruitment forecasting models serve as enhancements to the decision process of managing Pacific herring fisheries.
    • Intertidal community development along a distance/age gradient in a tidewater glacial fjord

      Sharman, Lewis Crook (1987-12)
      Glacier Bay has recently undergone rapid deglaciation, exposing new substrates to colonization and biological development. There is a clearly defined increase in marine intertidal community development with substrate age (0-200 y) and distance (0-90 km) from present-day locations of tidewater glacier termini. The objectives of this research were (1) to describe length-of-fjord patterns of intertidal community composition and corresponding gradients of the near-surface marine physical environment and (2) to use this approach to evaluate the relative contributions of substrate age and physical factors to determining the degree of community development. Distance and age were almost perfectly correlated. Intertidal species richness increased linearly with distance/age. Environmental factors can be grouped into those that also varied linearly along this gradient, and those that varied exponentially. Distance from the glaciers and the other linearly correlated marine environmental factors of water temperature, salinity, and suspended particulate nitrogen factors are probably the most important determinants of intertidal community development.
    • Intrinsic Markers In Avian Populations: Explorations In Stable Isotopes, Contaminants, And Genetics

      Rocque, Deborah Anne; Winker, Kevin; Duffy, Lawrence K.; Ben-David, Merav; Barry, Ronald P. (2003)
      This research outlines the diversity of questions that intrinsic markers have the potential to answer and demonstrates some of these marker's limitations and successes. To test the working hypothesis that feathers grown on different continents have significantly different stable isotope ratios in commonly used markers, I analyzed stable isotopes in two generations of feathers from three species of birds that breed at high latitudes and winter on different continents. As expected, significant differences in stable isotope ratios were detected between summer- and winter-grown feathers in both plover species (Pluvialis fulva and P. domininca). However, no differences were found between the two groups of winter-grown plover feathers, despite being grown on different continents. Similarly, no differences were detected in isotope values between summer- and winter-grown feathers in northern wheatears (Oenanthe oenanthe). Large variances in isotope ratios limited the percentage of feathers correctly assigned to their origins to 41%. Atmospheric transport has been identified as the source of pollutants in several arctic ecosystems and has the potential to severely impact high-latitude populations. To determine whether long-range atmospheric transport, point sources, or migratory prey were sources of contaminants in the North Pacific, birds from two trophic levels were sampled across the longitudinal transect of the Aleutian Archipelago. Carbon isotope ratios differed among islands, thereby linking birds to island food webs and ruling out contaminant transfer through migratory prey. Patterns in some PCB congeners indicated local point sources, but significant west-to-east declines in contaminant concentrations for the majority of detected organochlorines provided evidence of long-range transport. Linking individuals to source populations using intrinsic markers has only been successful at broad scales. To determine whether increased resolution among populations could be achieved by merging multiple intrinsic marker classes, a new analytical procedure was developed. Discrete and continuous markers were combined to evaluate a Bayesian method of assignment across marker classes. For three datasets, two real and one simulated, the percentage of individuals assigned to correct source populations increased with the addition of markers and marker classes. In all cases, the maximum number of individuals was correctly assigned when all marker classes were combined.
    • Invasive elodea threatens remote ecosystem services in Alaska: a spatially-explicit bioeconomic risk analysis

      Schwoerer, Tobias; Little, Joseph; Adkison, Milo; Baek, Jungho; Hayward, Greg; Morton, John (2017-05)
      This dissertation links human and ecological systems research to analyze resource management decisions for elodea, Alaska's first submerged aquatic invasive plant. The plant likely made it to Alaska through the aquarium trade. It was first discovered in urban parts of the state but is being introduced to remote water bodies by floatplanes and other pathways. Once introduced, elodea changes freshwater systems in ways that can threaten salmon and make floatplane destinations inaccessible. The analysis integrates multiple social and ecological data to estimate the potential future economic loss associated with its introduction to salmon fisheries and floatplane pilots. For estimating the effects on commercial sockeye fisheries, multiple methods of expert elicitation are used to quantify and validate expert opinion about elodea's ecological effects on salmon. These effects are believed to most likely be negative, but can in some instances be positive. Combined with market-based economic valuation, the approach accounts for the full range of potential ecological and economic effects. For analyzing the lost trip values to floatplane pilots, the analysis uses contingent valuation to estimate recreation demand for landing spots. A spatially-explicit model consisting of seven regions simulates elodea's spread across Alaska and its erratic population dynamics. This simulation model accounts for the change in region-specific colonization rates as elodea populations are eradicated. The most probable economic loss to commercial fisheries and recreational floatplane pilots is $97 million per year, with a 5% chance that combined losses exceed $456 million annually. The analysis describes how loss varies among stakeholders and regions, with more than half of statewide loss accruing to commercial sockeye salmon fisheries in Bristol Bay. Upfront management of all existing invasions is found to be the optimal management strategy for minimizing long-term loss. Even though the range of future economic loss is large, the certainty of long-term damage favors investments to eradicate current invasions and prevent new arrivals. The study serves as a step toward risk management aimed at protecting productive ecosystems of national and global significance.
    • Invasive plants and pollination of Alaskan berry species: integrating ecology and education

      Spellman, Katie Villano; Mulder, Christa; Wagner, Diane; McGuire, A. David; Conner, Laura; Carlson, Matthew (2015-05)
      A rapidly changing climate and human disturbance patterns have accelerated the spread of invasive plants species in Alaska. Non-native plant invasions can disrupt pollinator services to native plants and have the potential to impact the pollination and fruit set in berry species important for subsistence harvest. My dissertation aims to address the dual need for greater understanding of the impacts of invasive plants on pollination of berry species in boreal ecosystems and the need for research on education strategies that best prepare Alaskans to respond to the issue. I integrate an ecological field experiment, a citizen science program where data is used to validate phenology models derived from heraium data, and an invasive plants education experiment testing the effects of a metacognitive learning intervention to provide multiple perspectives that inform the management of invasive plants in Alaska. The ecological field experiment found that invasive Melilotus albus acts as a magnet species for pollinators, which increased seed production in Vaccinium vitis-idaea, slightly decreased pollination in Rhododendron groenlandicum, and had no detectable interactions with Vaccinium uliginosum. The impact M. albus had on R. groenlandicum changed with distance from the invasive plant patch, but the impact on V. vitis-idaea did not. Using data from a statewide citizen science program monitoring the phenology of these species, I found that herbarium-based phenology models were valid for assessing relative shifts in phenology of these species across Alaska. Employing the research on M. albus and the berry species as a test case, I found that students who received the metacognitive learning intervention show long-term improvement in metacognitive skills compared to students in the control group, but that the groups did not differ in their ability to apply resilience thinking skills to the environmental problem-solving. I synthesized social-ecological resilience and education research to investigate how citizen science and metacognitive learning could contribute to the capacity of Alaskans to respond to social-ecological change. Together, the ecology and education research presented here provide diverse perspectives on how to best manage and build the human capacity to manage M. albus near subsistence plant species.
    • Inversion of focal mechanism data for the directions of stress near Redoubt Volcano, Alaska

      Sánchez-Aguilar, John Jairo; McNutt, Stephen R.; Christensen, Douglas H.; Gardner, James E.; Moran, Seth C.; Wyss, Max (2000-12)
    • Investigating A Yup'Ik Immersion Program: What Determines Success?

      Green, Jean Renee; Coles-Ritchie, Marilee (2010)
      This research stems from my connectedness to a particular village, which will be referred to as Naparyaraq1. Unlike the majority of research on Alaska Native language issues, which primarily are from the point of view from an outsider, this research is unique in that my role as a community member has allows me an insider perspective of our Yup'ik Immersion Program. When dealing with Indigenous language issues, it is important that the impetus for change and improvements come from the local people. The primary goal of the Naparyaraq Immersion Program resulted from the communities desire to create change Community members wanted to keep the Yup'ik language alive. Growing up in Naparyaraq and my familiarity with the language issues has also driven me to be a personal participant in this change. Using focus groups, interviews, classroom observations, and field notes, the main goal of this Master's thesis is to inform the teachers and school community of the Naparyaraq Yup'ik Immersion Program in order to continue to help make improvements. Some of the issues which are addressed in this research include information related to: language use, success, training, language use at home, support, success, quality staff, assessment, need for teacher collaboration, and curriculum. 1Naparyaraq is a pseudonym. All names and places in the thesis are pseudonyms.
    • Investigating ancient bison migration in Alaska: a bottom up approach using isotopes

      Funck, Juliette Marie; Wooller, Matthew; Druckenmiller, Patrick; Hundertmark, Kris; Ruether, Joshua (2020-05)
      Once abundant in the Arctic, bison (Bison bison) declined almost to extinction in the North but have subsequently been reintroduced into Alaska. The predecessors of these modern bison were the ancient steppe bison (Bison priscus), which were abundant throughout the Northern Hemisphere before their extinction during the Holocene. This thesis investigates the ecology and landscape-use of both the present-day wood bison (Bison bison athabascae) and the ancient steppe bison in Alaska using stable isotopes, among other methods. The stable carbon and nitrogen isotope compositions of animal tissues are traditionally used to investigate diet. However, this thesis uses the isotope composition of tail hairs from present day wood bison as a proxy for their nutritional stress. Nutritional stress of some wood bison appears to be influenced not only by food shortage during hard seasons, but also due to long-distance mobility. This insight provides a key to understanding the challenges of reintroduction of the species into Alaska today, and can also be applied to understand the nutritional stress and cost of dispersal by ancient animals. Whereas the mobility of present-day bison can be tracked using sophisticated satellite tracking technologies, studies of the paleo-mobility of ancient bison rely on isotopic markers such as strontium and oxygen isotope ratios preserved in their teeth. To aid this approach using isotopic geolocation, this thesis creates a map of bioavailable strontium modeled and based on strontium isotope composition of present-day rodent teeth from across Alaska. It then compares this map, together with an existing oxygen isotope map of precipitation in Alaska, with the strontium and oxygen isotopes preserved in a suite of ancient bison from Northern Alaska. This comparison brings to light some of the major habitation regions used by Bison on the North Slope of Alaska over the last ~50,000 years. Finally, these findings subsequently contribute to a detailed paleoecological investigation of a mostly articulated and complete ancient steppe bison found on the North Slope of Alaska. This final study reveals the life-history of an individual bison that dispersed from the coastal plain to the foothills of the Brooks Range early in his life, and shows that the trip was nutritionally costly. This information is combined with a suite of other paleoecological methods to provide a vivid life history of this ancient bison. We introduce new methodologies for studying these ancient animals that seek to bridge the gap between how we study present-day and the past.
    • Investigating marine particle distributions and processes using in situ optical imaging in the Gulf of Alaska

      Turner, Jessica S.; McDonnell, Andrew; Johnson, Mark; Islas, Ana Aguilar (2015-12)
      The Gulf of Alaska is a seasonally productive ecosystem surrounded by glaciated coastal mountains with high precipitation. With a combination of high biological production, inputs of suspended sediments from glacial runoff, and contrasting nutrient regimes in offshore and shelf environments, there is a great need to study particle cycling in this region. I measured the concentrations and size distributions of large marine particles (0.06-27 mm) during four cruises in 2014 and 2015 using the Underwater Vision Profiler (UVP). The UVP produces high resolution depth profiles of particle concentrations and size distributions throughout the water column, while generating individual images of objects >500 μm including marine snow particles and mesozooplankton. The objectives of this study were to 1) describe spatial variability in particle concentrations and size distributions, and 2) use that variability to identify driving processes. I hypothesized that UVP particle concentrations and size distributions would follow patterns in chlorophyll a concentrations. Results did not support this hypothesis. Instead, a major contrast between shelf and offshore particle concentrations and sizes was observed. Total concentrations of particles increased with proximity to glacial and fluvial inputs. Over the shelf, particle concentrations on the order of 1000-10,000/L were 1-2 orders of magnitude greater than offshore concentrations on the order of 100/L. Driving processes over the shelf included terrigenous inputs from land, resuspension of bottom sediments, and advective transport of those inputs along and across the shelf. Offshore, biological processes were drivers of spatial variability in particle concentration and size. High quantities of terrigenous sediments could have implications for enhanced particle flux due to ballasting effects and for offshore transport of particulate phase iron to the central iron-limited gyre. The dominance of resuspended material in shelf processes will inform the location of future studies of the biological pump in the coastal Gulf of Alaska. This work highlights the importance of continental margins in global biogeochemical processes.
    • Investigating The Retention Of Bright And Dark Ejecta From Small Rayed Craters On Mars

      Calef, Fred J., Iii; Herrick, Robert R. (2010)
      Impact cratering is one of the principal geologic processes operating throughout the solar system. On Mars, small rayed impact craters (SRC) form continuously and randomly on the surface. Ejecta retention, the timespan and ability of excavated ejecta to remain in place around a crater rim, records a lineage of recent surface processes. However, the timescales under which small rayed craters are produced and their origin, whether terrestrial or cosmic, plays an important role in further investigating surface processes and possible recent climate variations. By examining thousands of randomly chosen panchromatic images from the Mars Orbiter Camera Narrow Angle (MOCNA) camera, a population of 630 SRC was catalogued across three equatorial and two polar regions on Mars. The survey of MOCNA images also revealed intriguing Enigmatic Linear Features (ELFs) in the northern hemisphere of Mars, which a short side study revealed to be a unique form of dust-devil track. From statistically examining several physical parameters, dust deposition and periglacial erosion were found to be the major factors affecting ejecta retention for the SRC. SRC morphology revealed ejecta retention sequences that followed four stages of ejecta retention from the initial impact to eventual erasure from the surface. By reconstructing the current cratering rate from estimates of atmospheric filtering, it was possible to calculate the ejecta retention age across Mars. In general, SRC ejecta are retained on the surface for <100 ka. Based on ejecta morphology and retention age estimates, a possible shift from depositional to erosional processes just south of the Martian equator is suspected to have occurred within this timeframe.
    • Investigation and development of a mathematical model for the oxidation of cyanide in the INCO SO₂/O₂ process

      Oleson, James L. (2003-12)
      The purpose of this study was to develop a mathematical model to describe the oxidation of cyanide with SO₂ as proposed in the INCO process. This research employed a direct method for measuring the change in cyanide concentration with respect to time as affected by varying concentrations of SO₂ and copper and pH. This model may be applicable in determining optimum conditions in a process well known and used in the mining industry.