241 research outputs found

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    Predicting the Cutting Time of Cottage Cheese Using Backscatter Measurements

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    An automated system for monitoring culture growth and determining coagulum cutting time is needed for cottage cheese manufacturing. A light backscatter measurement system was designed and installed in a local cottage cheese manufacturing plant. A cutting time prediction algorithm was developed using parameters generated from the backscatter profile. The cutting time prediction algorithm, Tcut = Tmax + β2 S, used two time-based parameters generated from the backscatter profile (Tmax and S) and one operator selected parameter, β2, to predict the coagulum cutting time, Tcut. The standard error of prediction for the algorithm was 6.4 min and was an improvement over the standard error of 8.7 min previously reported (Payne et al., 1998). The algorithm is more robust than that used by Payne et al. (1998) because it predicts cutting time based on a measure of coagulation kinetics, S, and eliminates the uncertainty of the culture starting time from the algorithm. In addition, a method was proposed for continuous monitoring of culture growth during the first 210 min of the process

    Diffuse Reflectance Changes During the Culture of Cottage Cheese

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    A sensor for measuring diffuse reflectance of milk during the typical 6-h culture of cottage cheese was installed in a local manufacturing facility. Diffuse reflectance was found to increase slowly during the first three hours of the culture and increase rapidly toward the end of fermentation. The correlation between parameters generated from the diffuse reflectance profile and cutting time was sufficient to develop an algorithm for cutting time prediction. An algorithm incorporating tmax (time from adding culture to the maximum rate of change in reflectance) and slope of the reflectance curve at tmax predicted the operator selected cutting time with a standard error of 8.7 min

    Light Backscatter of Milk Products for Transition Sensing Using Optical Fibers

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    Transition sensors are needed, particularly in the dairy industry, for detecting transitions in pipe flow systems from product-to-water or product-to-product (such as from chocolate to vanilla ice cream mix). Transition information is used to automatically sequence valves to minimize product waste. Optical fibers were used to measure light backscatter between 400 and 950 nm as a function of milk concentration in water and milkfat concentration in milk. The normalized response (100% for product and 0% for water) as a function of product concentration in water was approximately logarithmic for skim milk between 400 and 900 nm and approximately linear for milk containing 1, 2, and 3.2% milkfat. The backscatter ratio (response relative to that for skim milk) as a function of milkfat in milk was wavelength dependent with longer wavelengths being more sensitive. The backscatter ratio at 900 nm for milk containing 3.2% homogenized fat was nearly four times that for skim milk. Backscatter ratio saturated (minimal response with increased milkfat) at 8% milkfat for homogenized cream and 16% milkfat for unhomogenized cream. Light backscatter for near infrared wavelengths around 900 nm was found ideally suited for transition sensing of dairy products and was found particularly sensitive to milkfat content. Light backscatter was found less suitable for discriminating between high milkfat products

    Fiber Optic Sensor Response to High Levels of Fat in Cream

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    A light backscatter technique using optical fibers to deliver and receive light was investigated for measuring the milkfat content of unhomogenized cream. Light backscatter through cream at wavelengths of 450 to 900 nm was measured for fiber separation distances from 2 to 6.5 mm and for cream containing 10 to ~40 weight percent (wt%) milkfat. Unhomogenized cream (~40 wt% milkfat) was mixed with skim milk (~0.05 wt% milkfat) to yield samples with five different milkfat levels. Three optical response models were tested for correlation with milkfat content: one using the light intensity measurement at a single separation distance, the second using the ratio of the light intensity at two distances, and a third using the light intensity as a function of separation distance based on the backscatter of light in a particulate solution. The calibration equations from all three methods were used to predict milkfat content in the evaluation samples with root mean square errors (RMSEs) of 1.5 to 2.0 wt%. Statistical analysis did not find a significant difference between the three methods. For simplicity, using the ratio of the intensities measured and two different separation distances is attractive for further sensor design

    Master of Public Service and Administration Program Review and Evaluation

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    Assessing the quality and effectiveness of educational programs is becoming increasingly important. Ensuring the quality of Master of Public Administration (MPA) programs, like that at the Bush School of Government and Public Service, is even more critical. This capstone designed and implemented evaluative methods to assess the MPSA program. The group designed and conducted data collection and analysis to identify the program�s strengths and limitations by collecting alumni feedback. This project helped the MPSA program meet accreditation requirements and provided input to the next self-study report to be completed by the program during the 2012-2013 academic year. The capstone created and distributed an alumni survey to MPSA graduates and conducted alumni focus groups. The capstone report consists of a literature review followed by a summary of the research methodologies applied in the project, and concludes with results and a discussion of the findings.Report Submitted to Dr. Jeryl Mumpower, Director of the MPSA Progra

    Prevalence and determinants of the use of self-tests by members of the public: a mixed methods study

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    Background Self-tests can be used by members of the public to diagnose conditions without involving a doctor, nurse or other health professional. As technologies to design and manufacture diagnostic tests have developed, a range of self-tests have become available to the public to buy over-the-counter and via the Internet. This study aims to describe how many people have used self-tests and identify factors associated with their use. Methods A postal questionnaire will elicit basic information, including sociodemographic characteristics, and whether the person has used or would use specified self-tests. Consent will be sought to recontact people who want to participate further in the study, and interviews and focus groups will be used to develop hypotheses about factors associated with self-test use. These hypotheses will be tested in a case-control study. An in-depth questionnaire will be developed incorporating the identified factors. This will be sent to: people who have used a self-test (cases); people who have not used a self-test but would use one in the future (controls); and people who have not used and would not use a self-test (controls). Logistic regression analysis will be used to establish which factors are associated with self-test use. Discussion Self-tests do have potential benefits, for example privacy and convenience, but also potential harms, for example delay seeking treatment after a true negative result when the symptoms are actually due to another condition. It is anticipated that the outcomes from this study will include recommendations about how to improve the appropriate use of self-tests and existing health services, as well as information to prepare health professionals for patients who have used self-tests
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