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    The alternative uses of disused dairy factories in Taranaki : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Geography at Massey University
    (Massey University, 1983) O'Donnell, Christine Anne
    Small local dairy factories have long been a part of New Zealand's dairying heritage. No longer profitable in their original use, subsequent redundancy and abandonment has seen the appearance of the "disused dairy factory" in the rural landscape. In disuse these buildings find their greatest asset for potential reuse. As existing capital stock, these disused dairy factories manifest potential opportunities for enterprises other than dairying, to establish alternative uses. As a product of the past, the phenomenon of dairy factory reuse represents a change in use to meet the demands of the present. The extent to which this has been achieved, and how this pattern can be explained, evidences the interaction of past and present forces in effecting a potential future for these buildings.
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    Transport innovation and areal association in the Manawatu dairy industry : the role of transport from before 1880 to the present day and the impact of innovation in the areal association between supplier and factory and between factory and factory : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Geography at Massey University
    (Massey University, 1972) Wishnowsky, Richard Earle
    For the New Zealand dairy industry, "the principal - one might say the only important disadvantage - was the obstacle of distance...." (Philpott, 1937:11) Although concerned here with the difficulties of overseas transport, (he suggested that time and invention had largely overcome the obstacles of distance) the comment is equally applicable to the difficulties of internal transport. Transport is an important element in dairying but appears to have attracted little attention from researchers. A review of the history of dairying reveals a series of development phases, each of which appears related to transport developments. The first part of this thesis, then, is an historical review of the period from before 1880 to the present day with particular emphasis upon transport methods and innovations. Emphasis has been given, however, to developments at tho factory rather than the farm level. From a consideration of these historical developments, it becomes increasingly evident that each phase has been associated with distinctive patterns of land use and the development of specialised dairying "regions".
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    Neural network model predictive control of a ultra high temperature milk treatment plant : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Engineering and Automation at Massey University
    (Massey University, 1997) Karla, Venkateswara Rao
    This thesis reports the development of a Model Predictive Control system for a Ultra High Temperature milk treatment pilot plant. This control system utilises an Artificial Neural Network model of the plant dynamics. The entire process was divided into two parts for modelling purposes. Separate models were trained; one for simulating the dynamics of the hot water heating loop and the second the dynamics of the heat exchanger circuit. The two sub-models, when concatenated, form a complete model of the plant referred to as a composite neural network model. The results of training and testing of the sub-models with various sets of plant data were presented. Of all the possible combination of sub-models, the best trained and tested sub-models were concatenated to form the best composite network model, and the combination of worst sub-models to form worst composite network model. Two model predictive control (MPC) systems for the process were developed, one using the best composite network model for prediction purposes and to act as the plant, and the other using the worst composite model for prediction and best composite model as the plant. Both the developed MPC systems were evaluated in terms of setpoint tracking and disturbance rejection. As a part of these performance tests, a PI (Proportional-Integral) control system of the UHT plant was developed in a simulated environment using the best composite neural network model to act as the plant. The responses of both the MPC control systems were studied and compared with the responses of the PI control system.
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    Development of an in-line CIP sensor : a dissertation submitted in partial satisfaction of the requirements for the degree of Masters of Technology in Food Engineering
    (Massey University, 2000) Croy, Richard J
    The need to spend a few hours cleaning milk powder plants at least once every 24 hours is the cause of a significant amount of downtime for a plant. This downtime is worth millions of dollars of lost production time to the New Zealand dairy industry each year. Optimisation of the cleaning-in-place (CIP) systems used to clean milk powder factories has been limited by the lack of a method for measuring the amount of fouling throughout a plant without dismantling equipment for visual inspection. A sensor that could measure the amount of fouling remaining on a plant surface during CIP would allow cleaning rates and cleaning times to be determined for each cleaning cycle. Areas of intense fouling within the plant could also be mapped out using such a sensor. Research was conducted to develop a method for using a heat flux sensor to measure the amount of fouling remaining on a stainless steel surface during CIP. A pilot plant was built to replicate the pre-heating and fouling processes in a milk powder plant. The pilot plant had a cleaning-in-place system that cleaned the plant in a manner as similar as possible to that used in the dairy industry. Results from pilot plant trials showed that the heat flux sensor reflected changes in the fouling mass during cleaning. The heat transfer coefficient was low in the presence of fouling on the measured surface. As fouling was removed during CIP the overall heat transfer coefficient would increase. The probe allowed the estimation of the cleaning rate and cleaning time of the measured surface. The extent of fouling removed during cleaning could also be determined. Cleaning was found to be a relatively rapid process. Fouling layers of about 1 mm thickness took about 5 minutes of washing with 1.0% w/w caustic to become almost visually clean. Visual observations of a fouling layer during cleaning showed that cleaning was a process of attrition of the fouling surface. No lumps of fouling were seen breaking off the fouling layer during cleaning. Accurate and fast-responding temperature sensors to measure the CIP fluid temperature were found to be essential to the performance of the CIP monitoring system. When commercial Resistance Temperature Detectors (RTDs) mounted in a stainless steel sheath were used to measure the CIP fluid temperature the slow response time of the RTDs caused anomalies in the heat transfer coefficient trace. Heat loss from the RTD tip to its surroundings was also found to cause offset in temperature measurements. These anomalies were not seen when naked thermocouples were used to measure the CIP fluid temperature. The effect of changes in the thermophysical properties of the CIP solutions on the heat transfer coefficient during cleaning was also investigated. Changes in temperature were found to have the largest effect on the heat transfer coefficient. A method for compensating the heat transfer coefficient trace for changes in CIP fluid temperature was developed. The compensation was justified by predictions calculated from fundamental heat transfer theory. The concentration of soil or nitric acid did not significantly affect the heat transfer coefficient. The addition of caustic soda to the process fluid caused a very small decrease in the heat transfer coefficient. An industrial trial of the heat flux sensor was made at Kiwi Coop. Dairies Ltds Pahiatua Milk Powder Factory. The heat flux sensor was attached to the pipe directly following the direct steam injection unit (DSI) used to pre-heat milk before it entered the evaporator. The heat transfer coefficient was measured using the heat flux sensor and an existing RTD temperature probe measuring the process fluid temperature downstream of the direct steam injection unit. The CIP monitoring system was able to measure the build up of fouling during milk processing. However instability in the DSI during CIP lead to fluctuating process fluid temperatures during CIP making accurate measurement of the heat transfer coefficient impossible. A fast-response temperature sensor close to the heat flux sensor would have been needed for an accurate measurement. The existing RTD was however of a type similar to those that had given problems in earlier laboratory experiments. Much of the data collected from the heat flux sensor and the process fluid temperature sensor at Pahiatua contained significant noise or interference. The cause of this interference is unknown but it was likely due to electrical interference from powerful electrical devices within the plant. Amplification of the signal from the heat flux sensor is therefore recommended for industrial environments along with special attention to signal wire sheilding.
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    The effect of silver ion-implantation of stainless steel on bacterial adhesion and biofilm formation : a thesis presented in partial fulfilment of the requirements for a Master of Science in Microbiology at Massey University, Palmerston North, New Zealand
    (Massey University, 2012) Dhillon, Mehak
    Biofilms comprise an assembly of microbial communities attached to a surface and enclosed in a polysaccharide matrix. Biofilms are a problem in dairy manufacturing plants where they cause biofouling of the stainless steel surface, resulting in product contamination and the need to shorten manufacturing runs for frequent cleaning. The equipment has to be thoroughly cleaned at regular intervals to remove biofilms. Clean-In-Place (CIP) procedures used in dairy manufacturing plants are not effective enough to remove all the biofilm cells as the extracellular polysaccharide (EPS), an integral part of a biofilm, reduces the penetration of cleaning agents. One possible alternative method to control biofilm growth involves surface modification of the stainless steel by implanting silver ions to prevent the attachment of viable bacteria that would otherwise form biofilms. Stainless steel coupons, implanted with 1 × 1016 silver ions per cm2, and control stainless steel coupons were tested for the attachment of Streptococcus thermophilus and Pseudomonas fluorescens in various media for up to 30 minutes. Biofilm formation and EPS production for up to 24 hours was studied on the silver-implanted and control coupons in whole milk, skimmed milk and whey. It was found that there was higher attachment (0.49 and 0.18 log CFU per cm2 of S. thermophilus and P. fluorescens, respectively) on the stainless steel coupons than on the silver-implanted coupons in saline. In the presence of milk and whey, the difference in the attachment of bacteria on the two coupons reduced. Biofilm studies showed that the number of bacteria colonising both types of coupons was not statistically significantly different (P > 0.05). While the Live/Dead® BacLight™ Bacterial Viability stain showed that there were a few dead cells on the silver-implanted surfaces, scanning electron micrographs showed that the bacteria attached to a conditioning layer formed by the milk and whey proteins. Furthermore, both bacteria produced EPS, which, along with the conditioning film, might have masked the effect of silver ions from bacteria, resulting in similar numbers of bacteria present on the test and control coupons. Thus, due to the shielding effect of EPS and the conditioning film, the silver-implanted surfaces may be of limited practical value in the dairy industry.