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Title: SYSTEM-ON-CHIP ARCHITECTURES FOR SIGNAL PROCESSING AND COMMUNICAnONS
Creator: Niu, Sufeng
Date: 2012-04-30, 2012-05
Description: System-On-Chip (SOC) is one of the most popular Computer Aided Design (CAD) methodologies in electronic system design. In this research, SOC...
Show moreSystem-On-Chip (SOC) is one of the most popular Computer Aided Design (CAD) methodologies in electronic system design. In this research, SOC design is investigated in two different types of applications: i) low cost and power efficient applications; and ii) high performance computing applications. To explore low cost and power efficient design, a microcontroller based wireless medical system is investigated. Two wireless communication protocols for medical applications and patient monitoring are analyzed. In addition, the ZigBee stack developed by TI and a medical amplifier are discussed. For high performance SOC applications, implementations of several matrix operations are examined. An improved fixed-point hardware design of QR decomposition is introduced and optimized for Xilinx FPGAs. A Givens Rotation algorithm is implemented using a folded systolic array and the CORDIC algorithm. This approach is highly suitable for high-speed FPGAs or ASIC designs. It is found that the Xilinx XC5VLX110T FPGA is capable of running the QR decomposition at 246MHz.
M.S. in Electrical Engineering, May 2012
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Title: OPTIMAL BIDDING STRATEGY FOR HYDRO UNIT
Creator: Zhu, Renchen
Date: 2013-04-30, 2013-05
Description: The bidding price for the renewable energy is very different from some traditional energy, like gas, coal and so on, because when we produced...
Show moreThe bidding price for the renewable energy is very different from some traditional energy, like gas, coal and so on, because when we produced the renewable energy, the only cost is the generator unit cost, for example, wind power, water power and so on. People never need to pay the fuel price for the solar, water or wind. So here come one question how can we decide the energy price for these power. As we all know, the bidding price decided the profit for the generating company. Nowadays, more and more researches have been done in this field for every company want a good price to earn the highest profit. But for the renewable energy, they are different from the traditional energy which price is determined by the fuel price. So how to decide the bidding price of the renewable energy will be a good topic and question for us. To solve this problem, I will try to use an idea called minimum the imbalance in order to maximum the profit for those owners. This idea first has been applied in the wind unit. For my thesis, I will apply this idea to the hydro unit both with the storage and without storage. For each part, I will use some data to test. By these testing, the result will show this bidding strategy will be better.
M.S. in Electrical Engineering, May 2013
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Title: THERMODYNAMICS AND PHASE EQUILIBRIA OF HEUSLER ALLOYS
Creator: Chung, Yoonsung
Date: 2011-09, 2011-07
Description: Heusler compounds are of great interest for their properties such as shape memory, thermoelectric, ferromagnetic and spin polarization effects...
Show moreHeusler compounds are of great interest for their properties such as shape memory, thermoelectric, ferromagnetic and spin polarization effects that could lead to new mechanical and electronic devices. Currently, the study of Heusler alloys is focused on their electronic and magnetic properties, but the high temperature thermodynamic properties of these compounds have not been covered as much. A thorough knowledge of the thermodynamic properties and phase equilibria is required for developing this kind of alloys. This thesis is part of a systematic investigation of the thermodynamics and phase equilibria of ternary Heusler alloy systems. In this work, the high temperature reaction calorimeter was used to obtain the standard enthalpy of formation of compounds in the Ni2XSn (X = Ti, Zr, Hf, V and Nb) and Ni2TiX (X = Ga and In) ternary systems. It was confirmed the compound Ni2TaSn does not exist in the Heusler structure A Setaram Ligne 96 drop calorimeter was used to measure the heat content of Ni2TiSn as a function of temperature. Phase equilibria and crystal structures of Ni2TiSn, Ni2TiGa and Ni2TiIn were determined using XRD, SEM and EDS.
M.S. in Materials Science & Engineering, July 2011
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Title: ISOLATION OF MONOSPECIFIC ANTIBODY AGAINST SPLICED VARIANT OF DYSTROPHIN PROTEIN USING YEAST SURFACE DISPLAY TECHNIQUE
Creator: Saraswathi, Raj Prabu Vijayakumar
Date: 2011-05-04, 2011-05
Description: Dystrophin gene is the largest in the human genome with 79 exons covering greater than 0.1% of the total genome, located on the Xp21 locus of...
Show moreDystrophin gene is the largest in the human genome with 79 exons covering greater than 0.1% of the total genome, located on the Xp21 locus of the “X” chromosome resulting in a 427kDa protein, “Dystrophin”. Dystrophin is an important cytoskeletal protein which belongs to the β-Spectrin/α-actinin family of proteins. It comprises of an amino terminal domain, alpha helical coiled structure COOH domain, central rod region with 24 STRs and four proline rich hinge regions. It plays a vital role in localizing the Dystrophin glycoprotein complex (DGC) in the Sarcollema and is associated with the DGC in controlling the signaling events of certain proteins associated with DGC. The large size of the gene makes it more vulnerable to mutations resulting in partially functional or non-functional Dystrophin. The absence of Dystrophin results in disruption of sub sarcolemma-extracellular matrix linkage, loss of nitric oxide, progressive muscle weakening and muscle wasting leading to the death of patients typically before the end of their teenage. In certain cases alternatively spliced isoforms produce Dystrophin with reduced length yet stable and completely functionality. The main focus of this project was to select monospecific antibody against the more stable alternatively spliced variant D14 (15”16”) 17, which is functional and more stable compared to unspliced parent D14:17. The yeast surface display technique was used to effectively screen and select the yeast scFv clones containing the monospecific antibody against our target spliced variant D14 (15”16”) 17 protein and D2:3. The yeast scFv sub population was enriched by repeated MACS and FACS selection. Test colonies picked from the enriched scFv pool were confirmed via PCR and restriction digestion analysis. The scFv for the respective antigens were then sub cloned into pPnnl-9 secretion vector using YVH10 yeast cells via LiTRAFCO method. It was clear that by repeated MACS and FACS selection the scFv pool can be enriched and the yeast scFv clone sub population can be reduced to a significant level. The scFv sub cloned into Pnnl-9 secretion vector can be purified using affinity chromatography and the further affinity and avidity studies can be conducted.
M.S. in Biology, May 2011
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Title: Multivariable MPC system performance assessment, monitoring, and diagnosis
Creator: Schaffer, J., Cinar, A.
Date: 2004-03
Publisher: ELSEVIER SCI LTD
Description: This study focuses on performance assessment and monitoring of model predictive control systems. A methodology is proposed to determine a...
Show moreThis study focuses on performance assessment and monitoring of model predictive control systems. A methodology is proposed to determine a benchmark and monitor model predictive control performance on-line. A performance measure based on the ratio of historical and achieved performance is used for monitoring and a ratio of design and achieved performance is used for diagnosis. Performance monitoring and diagnosis of causes for poor performance are integrated. A real-time knowledge-based system is developed to supervise monitoring and diagnosis activities. Case studies with linear and nonlinear models of an evaporator illustrate the methodology and limitations of linearity assumptions.
Endnote format citation for DOI:10.1016/j.jprocont.2003.07.003
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Title: L2E ESTIMATOR FOR THE CATEGORICAL MODEL WITH ELASTIC NET PENALTY
Creator: Wang, Yuan
Date: 2017, 2017-07
Description: The logistic regression model is an important generalized linear model for the categorical data. The maximum likelihood estimation is mostly...
Show moreThe logistic regression model is an important generalized linear model for the categorical data. The maximum likelihood estimation is mostly used in estimating the parameters of the logistic regression model. However, the maximum likelihood estimation is very sensitive to outliers which will cause the inaccuracies of the fitted parameters and model selection in high-dimensional regression. Chi and Scott (2014) demonstrated by simulation that minimizing the integrated square error or L2 estimation (L2E) is a robust method to fit 2-class categorical models. They also showed that the L2E estimation method can select the right model even in the presence of many outliers in high dimensional scenarios. In my thesis, I extended the L2E estimation method from 2-class to 3-class based on the MM algorithm by Chi and Scott (2014). Then I demonstrated the properties above for 2-class categorical models are also applicable to 3-class ones.
M.S. in Applied Mathematics, July 2017
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Title: Multivariate statistical methods for monitoring continuous processes: Assessment of discrimination power of disturbance models and diagnosis of multiple disturbances
Creator: Raich, A. C., Cinar, A.
Date: 1995-11
Publisher: ELSEVIER SCIENCE BV
Description: A new methodology was reported [1,2] for integrated use of principal components analysis (PCA) and discriminant analysis in order to determine...
Show moreA new methodology was reported [1,2] for integrated use of principal components analysis (PCA) and discriminant analysis in order to determine out-of-control status of a continuous process and to diagnose the source causes for abnormal behavior. Most of the disturbances were identified with good rates of success, with a higher success rate for step or ramp type of disturbances. Quantitative tools that evaluate overlap and similarity between high-dimensional PCA models are proposed in this communication, and their implications on determining the discrimination power of PCA models of processes operating under disturbances are discussed. Diagnosis of several disturbances occurring simultaneously is also investigated. The criterion developed provide upper limits of discrimination power of various single and multiple process disturbances. The techniques developed are illustrated by assessing the process described by the Tennessee Eastman Control Challenge problem [3].
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Title: PARAMETRIC IMAGE ESTIMATION IN ANALYZER-BASED PHASE CONTRAST IMAGING
Creator: Caudevilla, Oriol
Date: 2014, 2014-07
Description: Since the discovery of X-rays, by W.E. Roentgen in 1895, absorption-contrast imaging has been widely used in medical diagnostic, for example:...
Show moreSince the discovery of X-rays, by W.E. Roentgen in 1895, absorption-contrast imaging has been widely used in medical diagnostic, for example: mammography, chest X-ray, angiography etc. Over the last 25 years many researchers have shown that phase-contrast X-ray imaging is capable of obtaining a better contrast then classical absorption-contrast imaging. This is especially true in soft tissue imaging like mammography or at higher Xrays energies. During the past five years a significant effort has made in development of a tabletop analyzer-based phase-contrast system. In this system a perfect crystal is used to generate a quasi-monochromatic beam, which after interacting with an object is analyzed by a second perfect crystal called analyzer. The need of quasi-monochromatic beam and the low brilliance of conventional X-ray sources (CXS) has been the major limiting factor for tabletop systems. The work presents in this thesis aims to develop novel reconstruction methods for tabletop analyzer-based phase-contrast imaging (ABI) systems. The presented reconstruction methods goal is to minimize the impact of CXS low brilliance by utilizing phase-contrast image formation model and maximum or maximum-a-posteriori Poisson likelihood approach. Finally, a fast-convergent conjugate gradient optimization algorithm has been derived specifically for Poisson likelihood function maximization.
M.S. in Electrical Engineering, July 2014
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Title: An Alternative Car Show: An Alternateive Vehicle Insfrastructure
Creator: Hopkins, Kyle
Date: 2010-07-29

Title: NEUTRON PRODUCTION IN THE M2 MUON BEAM LINE AT CERN
Creator: Draeger, Emily
Date: 2014, 2014-05
Description: Spallation neutrons produced from cosmic ray muons are a major source of backgrounds in underground physics experiments. Experiments have been...
Show moreSpallation neutrons produced from cosmic ray muons are a major source of backgrounds in underground physics experiments. Experiments have been done to study spallation neutron production and yield, but our understanding of these processes is still limited. There are various interactions that can produce spallation neutrons. Most of these production mechanisms are fairly well understood; much of the uncertainty in our understanding of spallation neutrons lies in mechanisms such as virtual photon exchange and the assumptions used to calculate the photonuclear cross section. Even the experiments that have been carried out do not agree with each other or theoretical calculations. Spallation neutron production mechanisms are discussed, as well as a new experiment to study spallation neutrons. The impact of this study on current and future underground physics experiments is also explored.
PH.D in Physics, May 2014
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Title: INTELLIGENT PROCESS-CONTROL WITH SUPERVISORY KNOWLEDGE-BASED SYSTEMS
Creator: Kendra, S. J., Basila, M. R., Cinar, A.
Date: 1994-06
Description: The integration of a supervisory knowledge-based system (KBS) with a multivariable control system is examined to provide robust multivariable...
Show moreThe integration of a supervisory knowledge-based system (KBS) with a multivariable control system is examined to provide robust multivariable control of a chemical reaction process. The supervisory KBS is capable of monitoring the process to detect system faults as well as assessing control system performance. If a control system performance deficiency is detected, the KBS formulates and implements the necessary corrective controller tuning. This adaptive capability reduces the conservatism of the robust control system. The underlying mechanisms are discussed and the re-tuning ability of the KBS is illustrated by using rigorous simulations of a chemical reaction process
Endnote format citation
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Title: Thermal conductivity
Creator: Bauer, W. Ernest, Jr
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/thermalconductiv00baue
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: POWER ANALYSIS AND CONTROL OPTIMIZATION OF A HIGH GAIN RESONANT DC-DC CONVERTER
Creator: Wu, Haowen
Date: 2017, 2017-05
Description: Applications of DC-DC converter require a high power, high efficiency performance, especially for automotive applications and renewable energy...
Show moreApplications of DC-DC converter require a high power, high efficiency performance, especially for automotive applications and renewable energy applications. A desired converter should have a fast response, stable output in different conditions. This thesis studies a novel high gain DC-DC resonant converter and its control. Based on the circuit analysis and operation evaluation, feed-forward and feedback control methods are proposed in order to achieve stability under variety of changes. Moreover, circuit topology is investigated in response to the efficiency improvement. Simulations in PSIM, PLECS and MATLAB Simulink have been carried out to validate the controller design and topology development. The simulation results are in consistence to the theoretical analysis. The overall high efficiency at nominal operating point is further increased.
M.S. in Electrical Engineering, May 2017
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Title: NOVEL FAULT DIAGNOSTIC TECHNIQUE AND UNIVERSAL SENSOR FOR PERMANENT MAGNET ELECTRIC MACHINES USING SEARCH COILS
Creator: Da, Yao
Date: 2012-04-23, 2012-05
Description: Over the past decade, permanent magnet synchronous machines (PMSMs) have gained significant popularity in industry, such as wind turbines and...
Show moreOver the past decade, permanent magnet synchronous machines (PMSMs) have gained significant popularity in industry, such as wind turbines and electric vehicles, owing to their high efficiency, high output power to volume ratio, and high torque to current ratio. In these mission critical applications, an unexpected fault or failure of the machine could lead to very high repair or replacement cost, or even catastrophic system failure. Therefore a robust and reliable health monitoring and fault diagnostic approach is desired, which could help in scheduling preventive maintenance to lengthen their lifespan and avoid machine failure. This dissertation presents a novel multi-faults diagnostic approach using search coils. These search coils are wound around armature teeth, so they typically need to be installed during manufacturing. But its immunity to high frequency harmonics makes it suitable for inverter/rectifier fed motors or generators, such as wind turbines and automotive systems. In addition, this method does not require the knowledge of proprietary constructional details of the machine. Since the electromagnetic flux is directly measured in this method, it provides much more information than any other scheme: the direction of eccentricity and the location of shorted windings. Furthermore, this method is also capable of evaluating the severity of each fault, which is of significant importance in mission critical applications such as automotive, aerospace and military applications. In addition to these uses, the search coils can be used as a universal sensor to estimate phase current or rotor position, which are critical information in a PMSM close-loop control, which allow it to work as a backup sensor for fault tolerant operation. The proposed fault detection scheme and universal sensor concept have been tested under several scenarios with Finite Element Analysis and experimentally validated.
Ph.D. in Electrical Engineering, May 2012
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Title: CELL-MATRIX INTERACTIONS IN ADIPOSE TISSUE FUNCTION
Creator: Vaicik, Marcella K.
Date: 2015, 2015-07
Description: The overall goal of this work is to apply in vivo and in vitro models to study the basement membrane protein laminin α4 (lama4) in adipocyte...
Show moreThe overall goal of this work is to apply in vivo and in vitro models to study the basement membrane protein laminin α4 (lama4) in adipocyte function. Adipose tissue accumulation, lipogenesis, and structure were examined in mice with a null mutation of the lama4 gene (Lama4−/−) and compared to wild-type animals (Lama4+/+). The Lama4−/−mice phenotype was investigated to evaluate if the differences were due specifically to the adipose tissue function. Physical activity and food intake does not differ between Lama4+/+ and Lama4−/− mice. However, Lama4−/− mice have a significantly increased metabolic rate at 25°C and 16°C compared to Lama4+/+ mice. In contrast, in thermoneutral conditions at 30°C both Lama4+/+ and Lama4−/− mice exhibit equivalent metabolic rates. Interestingly, when room temperature housed mice fat pads were evaluated with immunohistochemistry, Lama4−/− mice exhibit significantly increased UCP-1 expression in subcutaneous adipose. These results suggest that beiging, white to brown adipocytes, in subcutaneous adipose tissue in Lama4−/− mice may lead to decreased adipose tissue accumulation and improved metabolic function. While animal models indicate the absence of lama4 results in more beiging in subcutaneous adipose tissue, an in vitro tissue engineered model was developed to study the adipocyte function in a controlled microenvironment. Primary cell spheroids developed from Lama4+/+ and Lama4−/− were incorporated into synthetic poly(ethylene glycol) (PEG) hydrogels within a range of stiffnesses. When the cells were given the same chemical cues their functions differed depending upon microenvironment stiffness. Beige function in adipocyte cells in 3D can be influenced by matrix stiffness. In conclusion, the laminin alpha 4 basement membrane protein absence in adipose tissue results in adipocyte functional changes in vivo. The Lama4−/− mice have resistance to diet induced weight gain and increased metabolic rate at room temperature and when cold challenged. The Lama4−/− mice had increased beiging in the subcutaneous depot. Additionally, a tissue engineered model was developed to further study cell-ECM interactions first identified in an animal model. These in vivo findings and the engineered model of adipose tissue have great potential for studying obesity and other adipose related diseases. Future work will require continued interdisciplinary collaboration towards the successful identification and screening of novel therapeutics using engineered tissue models.
Ph.D. in Biomedical Engineering, July 2015
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Title: A system of multiplex telephony by the use of vacuum tubes
Creator: Arnold, E. H., Throop, A. R.
Date: 2009, 1919
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/systemofmultiple00arno
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaves 44-45

Title: RECEIVER AUTONOMOUS INTEGRITY MONITORING AGAINST ORBIT EPHEMERIS FAULTS IN CARRIER PHASE DIFFERENTIAL GPS
Creator: Stevanovic, Stefan
Date: 2013-04-18, 2013-05
Description: This work investigates the potential of the Global Positioning System (GPS) to enable a safe approach for rendezvous applications including...
Show moreThis work investigates the potential of the Global Positioning System (GPS) to enable a safe approach for rendezvous applications including shipboard landing of military aircraft. GPS has been shown to have the necessary accuracy for such an operation, and could potentially replace the existing radar or laser based systems. [Kha08][WPF08]1 However, to ensure safe operation, GPS must also be able to avoid hazardous situations. Shipboard aircraft approach navigation is an example rendezvous application requiring both high accuracy and high integrity. In this work, GPS measurement error models and orbit ephemeris fault (OEF) detection algorithms are developed for rendezvous applications, and performance is analyzed for the aircraft shipboard landing application. Both reference station and user based monitors can be used for orbit ephemeris fault detection. The available reference monitors either require a stationary reference receiver, or cannot protect against all types of orbit ephemeris faults. As an alternative, this work develops and investigates the use of receiver autonomous integrity monitoring (RAIM), which is user-based. Two contrasting algorithms, differential RAIM (DRAIM) and relative RAIM (RRAIM) are derived and analyzed for a realistic shipboard landing application. DRAIM is most effective when the aircraft first begins the approach. On the other hand, RRAIM performs best near the end of the approach. Assessing integrity risk is shown to be a major challenge for the RRAIM algorithm. Thus, a new unified RAIM (URAIM) concept is introduced. It seamlessly integrates DRAIM and RRAIM into a single detection algorithm, and also facilitates integrity risk evaluation. This is because the URAIM measurement equation can be used for both position estimation as well as fault detection. 1Corresponding to references in the Bibliography. xii Since high accuracy is desired, fixing integer cycle ambiguities is required. The Enforced Position-Domain Integrity-Risk Cycle Resolution Algorithm (EPIC) method of integrity risk bounding is used along with the URAIM fault detection algorithm in what we call the EPIC-URAIM algorithm. In general, the OEF will interfere with the cycle resolution process. In this work, the EPIC integrity risk bound formula is modified to account for the presence of an OEF. The EPIC-URAIM algorithm is simulated for 1507 sea-based locations around the globe. An average global availability of accuracy and integrity of 98.6% is achieved. This work illustrates the feasibility of detecting orbit ephemeris faults with integrity, while simultaneously meeting stringent accuracy requirements for real-time rendezvous navigation applications.
M.S. in Mechanical and Aerospace Engineering, May 2013
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Title: BOUNDING ESTIMATION INTEGRITY RISK FOR LINEAR SYSTEMS WITH STRUCTURED STOCHASTIC MODELING UNCERTAINTY
Creator: Langel, Steven Edward
Date: 2014, 2014-05
Description: Safety critical estimation applications require quantification of integrity risk, which is the probability of the state estimate error...
Show moreSafety critical estimation applications require quantification of integrity risk, which is the probability of the state estimate error exceeding predefined bounds of acceptability. Integrity risk can only be evaluated when the state estimate error probability density function is precisely known, necessitating stochastic models that exactly describe measurement noise and disturbance inputs. Uncertainty in these models directly results in inaccurate assessments of integrity risk. This dissertation develops the first implementable methods to upper bound integrity risk when the autocorrelation functions of stochastic inputs reside between upper and lower bounding functions. The first part of this work considers real-valued estimation applications that use the Kalman filter or batch weighted least squares estimator. Explicit relations are developed between the estimate error variance and autocorrelation functions using a new generalized covariance matrix derived in this dissertation. From these expressions, two methods are provided to upper bound integrity risk. The first method enables fast computation of a conservative bound, and the second method produces the minimum upper bound via semi-definite optimization. Mixed real/integer estimation applications utilizing integer bootstrapping are the focus of the second part of this work. The integrity risk bound is formally defined as the global solution to a non-convex optimization problem over a polytope. Determination of the polytopic region is difficult, and two bounding approaches are initially developed for a circumscribing hyper-rectangular feasible region. Using an innovative method to define the polytope together with linear programming, a third method is derived to upper bound integrity risk over the true polytopic feasible region.
PH.D in Mechanical and Aerospace Engineering, May 2014
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Title: Teacher Knowledge Share (Semester Unknown) IPRO 320: Teacher Knowledge Share IPRO 320 MidTerm Presentation F08
Creator: Bern, David, Bochantin, Marike, Hartline, Julian, Mccall, Ian, Mick, Emily, Peake, Andrew, Pierce, Alison, Pindrik, Dmitriy, Quinn, Michael, Stanford, Carly, Tilatti, Michael
Date: 2008, 2008-12
Description: The goal of IPRO 320 is to create an online professional network for school teachers at the kindergarten through twelfth grade level to allow...
Show moreThe goal of IPRO 320 is to create an online professional network for school teachers at the kindergarten through twelfth grade level to allow for the sharing of ideas, lesson plans and other professionally relevant information. This is a continuing project which saw limited success in the previous semester in that a functioning web site was constructed based on surveys of public school teachers but it saw very little use. This semester, the planned approach is to build on the research generated last semester by performing additional market research with teachers. Following that, IPRO 320 will rework much of the previous web site by refining some of the features, adding additional ones as the research indicates and improving the website in general, both functionally and aesthetically.
Deliverables
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Title: SURVIVAL OF SALMONELLA ON CHAMOMILE, PEPPERMINT AND GREEN TEA DURING STORAGE RELATED TO TEMPERATURE AND HUMIDITY
Creator: Chen, Zhengzai
Date: 2013-04-24, 2013-05
Description: Botanical/herbal teas may contain antimicrobial compounds that will affect the survival and persistence of the native as well as contaminant...
Show moreBotanical/herbal teas may contain antimicrobial compounds that will affect the survival and persistence of the native as well as contaminant microflora. Although Salmonella are known for their ability to survive in low water activity environments, their survival on dry botanical/herbal teas has not been examined. The purpose of this work is to determine the survival of Salmonella on three types of teas, chamomile peppermint, and green tea under different storage conditions. In addition, the ability of Salmonella to grow in tea brewed with contaminated product was examined. A cocktail of four Salmonella serovars was inoculated onto 1 g samples of chamomile, peppermint, and green tea to give a starting cell population of approximately 10 log cfu/g. The inoculum was allowed to dry prior to storage at 25 °C and 35 °C and at low (<30% RH) and high (> 90% RH) humidity levels. At different time intervals up to 6 months, triplicate samples at each condition were evaluated for surviving Salmonella populations. In addition, samples were used to produce a low-temperature (sun) brewed tea and inoculated. Growth was assessed after 24 hr. Under the four storage conditions tested, survival followed the order 25°C/low RH > 35°C/low RH > 25°C/high RH > 35°C/high RH. Salmonella losses at 25°C/low RH occurred primarily during drying, after which populations showed little declines over 6 months. In contrast Salmonella decreased below detection after 45 days at 35°C and high RH in all teas tested. All teas tested supported the growth of Salmonella after brewing. Storage conditions significantly impact the survival of Salmonella in dried herbal teas. If Salmonella survives after storage, it may also survive and grow after a home brewing process.
M.S. in Food Safety and Technology, May 2013
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