title: The tetrad effect and geochemistry of apatite from the Altay Koktokay No. 3 pegmatite, Xinjiang, China: implications for pegmatite petrogenesis

authors: Cao, Ming-Jian

abstract: In order to better constrain the evolution and petrogenesis of pegmatite, geochemical analysis was conducted on a suite of apatite crystals from the Altay Koktokay No. 3 pegmatite, Xinjiang, China and from the granitic and amphibolitic wall rocks. Apatite samples derived from pegmatite zones show convex tetrad effects in their REE patterns, extremely negative Eu anomalies and non-chondritic Y/Ho ratios. In contrast, chondritic Y/Ho ratios and convex tetrad effects are observed in the muscovite granite suggesting that different processes caused non-chondritic Y/Ho ratios and lanthanide tetrad effects. Based on the occurrence of convex tetrad effects in the host rocks and their associated minerals, we propose that the tetrad effects are likely produced from immiscible fluoride and silicate melts. This is in contrast to previous explanations of the tetrad effect; i.e. surface weathering, fractional crystallization and/or fluid-rock interaction. Additionally, we put forward that extreme negative Eu and non-chondritic Y/Ho in apatite are likely caused by the large amount of hydrothermal fluid exsolved from the pegmatite melts. Evolution of melt composition was found to be the primary cause of inter and intra-crystal major and trace element variations in apatite. Mn entering into apatite via substitution of Ca is supported by the positive correlation between CaO and MnO. Different evolution trends in apatite composition imply different crystallization environments between wall rocks and pegmatite zones. Based on the geochemistry of apatite samples, it is likely that there is a genetic relationship between the source of muscovite granite and the source of the pegmatite.

text: The tetrad effect and geochemistry of apatite from the Altay Koktokay No. 3 pegmatite, Xinjiang, China: implications for pegmatite petrogenesis In order to better constrain the evolution and petrogenesis of pegmatite, geochemical analysis was conducted on a suite of apatite crystals from the Altay Koktokay No. 3 pegmatite, Xinjiang, China and from the granitic and amphibolitic wall rocks. Apatite samples derived from pegmatite zones show convex tetrad effects in their REE patterns, extremely negative Eu anomalies and non-chondritic Y/Ho ratios. In contrast, chondritic Y/Ho ratios and convex tetrad effects are observed in the muscovite granite suggesting that different processes caused non-chondritic Y/Ho ratios and lanthanide tetrad effects. Based on the occurrence of convex tetrad effects in the host rocks and their associated minerals, we propose that the tetrad effects are likely produced from immiscible fluoride and silicate melts. This is in contrast to previous explanations of the tetrad effect; i.e. surface weathering, fractional crystallization and/or fluid-rock interaction. Additionally, we put forward that extreme negative Eu and non-chondritic Y/Ho in apatite are likely caused by the large amount of hydrothermal fluid exsolved from the pegmatite melts. Evolution of melt composition was found to be the primary cause of inter and intra-crystal major and trace element variations in apatite. Mn entering into apatite via substitution of Ca is supported by the positive correlation between CaO and MnO. Different evolution trends in apatite composition imply different crystallization environments between wall rocks and pegmatite zones. Based on the geochemistry of apatite samples, it is likely that there is a genetic relationship between the source of muscovite granite and the source of the pegmatite.

year: 2013

title: Hardware in the loop evaluation of a hybrid heating system for increased energy efficiency and management

authors: Schumm, Gregor

abstract: This study presents the tests of a hybrid heating prototype, designed for retrofitting thermal treatment plants like pasteurization, to use hot water and steam in controlled ratios. In the food industry, steam with a temperature above 140°C usually supplies the thermal production processes. The majority of processes require temperatures below 100°C and could be supplied more eficiently by cogeneration, heat recovery or heat pumps. These low temperature heat sources can only be combined with the rigid steam system if the demand structure is changed to a hybrid use of hot water below 100°C and steam. The hybrid heating system (H2S) increases the energy efficiency by integrating the highest possible amount of low temperature heat and responds to sudden changes in the supply structure, like demand response strategies on intermittent renewable energies and the changing availability of hot water and steam. The technical implementation is realised by a hydraulic interconnection of heat exchangers and valves. A smart algorithm controls the integration of hot water and steam into the thermal process. For reasons of food safety and product quality defined process temperatures have to be met. Prerequisite for functional verification on a laboratory scale is a simulation of the process heat demand and potential of hot water during the entire production cycle. The load profiles and relevant process parameters are passed in real time to a hardware-in-the loop (HIL) test-bed and returned to the simulation respectively. Two scenarios, hot water integration from heat pump and demand response management with a gas engine CHP and an electrical steam generator, were evaluated and the functionality of the H2S was proved. Up to 78 % of the final energy demand can be reduced by the H2S based implementation of a heat pump. The control response of the system, even with fluctuating hot water potential and temperature, met the requirements of the dairy industry.

text: Hardware in the loop evaluation of a hybrid heating system for increased energy efficiency and management This study presents the tests of a hybrid heating prototype, designed for retrofitting thermal treatment plants like pasteurization, to use hot water and steam in controlled ratios. In the food industry, steam with a temperature above 140°C usually supplies the thermal production processes. The majority of processes require temperatures below 100°C and could be supplied more eficiently by cogeneration, heat recovery or heat pumps. These low temperature heat sources can only be combined with the rigid steam system if the demand structure is changed to a hybrid use of hot water below 100°C and steam. The hybrid heating system (H2S) increases the energy efficiency by integrating the highest possible amount of low temperature heat and responds to sudden changes in the supply structure, like demand response strategies on intermittent renewable energies and the changing availability of hot water and steam. The technical implementation is realised by a hydraulic interconnection of heat exchangers and valves. A smart algorithm controls the integration of hot water and steam into the thermal process. For reasons of food safety and product quality defined process temperatures have to be met. Prerequisite for functional verification on a laboratory scale is a simulation of the process heat demand and potential of hot water during the entire production cycle. The load profiles and relevant process parameters are passed in real time to a hardware-in-the loop (HIL) test-bed and returned to the simulation respectively. Two scenarios, hot water integration from heat pump and demand response management with a gas engine CHP and an electrical steam generator, were evaluated and the functionality of the H2S was proved. Up to 78 % of the final energy demand can be reduced by the H2S based implementation of a heat pump. The control response of the system, even with fluctuating hot water potential and temperature, met the requirements of the dairy industry.

year: 2016

title: A Maori and Psychology Research Unit

authors: Nikora, Linda Waimarie

subjects: Maori

abstract: Little psychological information and few applications have been informed by Maori centred research. The psychological research base available to support prevention or change strategies aimed at Maori is almost non-existent. Most information and applications are imported from outside of Aotearoa/New Zealand and are seldom subjected to vetting procedures to ensure adequacy and appropriateness. Even though numbers have changed slightly in the last 10 years, there are still too few Maori in the professional ranks of psychology, both as practitioners, teachers and researchers. More of everything is needed, and it was needed yesterday. At the University of Waikato, staff of the Psychology Department have recognised the need to support positive changes to rectify that situation described above.

This paper describes the fledgling development of a Maori and Psychology Research Unit and how it is intended to promote Maori centred-research, Maori-partnership research, and the scholarly development of Maori professionals. The first section deals with issues and challenges the MPRU expects to face in its development and is written by the first author. The second section describes the nature of learning and support that the MPRU will afford to a new generation of Maori researchers and scholars within the discipline of psychology. This section is written by the second author.

text: A Maori and Psychology Research Unit Little psychological information and few applications have been informed by Maori centred research. The psychological research base available to support prevention or change strategies aimed at Maori is almost non-existent. Most information and applications are imported from outside of Aotearoa/New Zealand and are seldom subjected to vetting procedures to ensure adequacy and appropriateness. Even though numbers have changed slightly in the last 10 years, there are still too few Maori in the professional ranks of psychology, both as practitioners, teachers and researchers. More of everything is needed, and it was needed yesterday. At the University of Waikato, staff of the Psychology Department have recognised the need to support positive changes to rectify that situation described above.

This paper describes the fledgling development of a Maori and Psychology Research Unit and how it is intended to promote Maori centred-research, Maori-partnership research, and the scholarly development of Maori professionals. The first section deals with issues and challenges the MPRU expects to face in its development and is written by the first author. The second section describes the nature of learning and support that the MPRU will afford to a new generation of Maori researchers and scholars within the discipline of psychology. This section is written by the second author.

year: 1998-07-01