title: Energy efficiency measures for batch retort sterilization in the food processing industry

authors: Peesel, Ron-Hendrik

abstract: The purpose of this study is to highlight the energy saving potentials of a batch retort sterilization process operated by steam and to develop concepts for improving its energy efficiency. By using the methodical approach of the Onion Diagram and the recovery of low grade heat sources, four comprehensive improved energy efficiency concepts have been developed. Two concepts increase the initial product temperature resulting in lower transient steam consumption rates and a decreased energy demand. The other two options transform the waste heat and the energy for product cooling into heat streams for supplying nearby heat sinks or other processes in the plant. Results show that the total energy demand can be reduced by more than 23 % and 42 % of the energy injected into the system can be recovered. The scope of the study focused on a single, independent retort to ensure the transferability of the concepts. This study also shows, using a practical example, the importance of a comprehensive process understanding and analysis prior to application of Pinch Analysis, which is needed to ensure that the correct waste heat stream temperatures are defined, necessary processing constraints are appreciated, and all possible heat sinks in the process are considered.

text: Energy efficiency measures for batch retort sterilization in the food processing industry The purpose of this study is to highlight the energy saving potentials of a batch retort sterilization process operated by steam and to develop concepts for improving its energy efficiency. By using the methodical approach of the Onion Diagram and the recovery of low grade heat sources, four comprehensive improved energy efficiency concepts have been developed. Two concepts increase the initial product temperature resulting in lower transient steam consumption rates and a decreased energy demand. The other two options transform the waste heat and the energy for product cooling into heat streams for supplying nearby heat sinks or other processes in the plant. Results show that the total energy demand can be reduced by more than 23 % and 42 % of the energy injected into the system can be recovered. The scope of the study focused on a single, independent retort to ensure the transferability of the concepts. This study also shows, using a practical example, the importance of a comprehensive process understanding and analysis prior to application of Pinch Analysis, which is needed to ensure that the correct waste heat stream temperatures are defined, necessary processing constraints are appreciated, and all possible heat sinks in the process are considered.

year: 2016

title: Uptake of ΣDDT, arsenic, cadmium, copper, and lead by lettuce and radish grown in contaminated horticultural soils

authors: Gaw, Sally K.

subjects: horticultural soil

abstract: Horticultural soils can contain elevated concentrations of selected trace elements and organochlorine pesticides as a result of long-term use of agrichemicals and soil amendments. A glasshouse study was undertaken to assess the uptake of weathered ΣDDT {sum of the p,p′- and o,p-isomers of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane], DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] and DDD[1,1-dichloro-2,2-bis(p-chlorophenyl)ethane]}, arsenic (As), cadmium (Cd), copper (Cu), and lead (Pb) residues by lettuce (Lactuca sativa) and radish (Raphanus sativus) from field-aged New Zealand horticultural soils. Concentrations of ΣDDT, DDT, DDE, Cd, Cu, and Pb in lettuce increased with increasing soil concentrations. In radish, similar relationships were observed for ΣDDT, DDE, and Cu. The bioaccumulation factors were less than 1 with the exception of Cd and decreased with increasing soil concentrations. Lettuce Cd concentrations for plants grown on four out of 10 assayed soils were equivalent to or exceeded the New Zealand food standard for leafy vegetables of 0.1 mg kg−1 fresh weight. Concentrations of As, Pb, and ΣDDT did not exceed available food standards. Overall, these results demonstrate that aged residues of ΣDDT, As, Cd, Cu, and Pb in horticultural soils have remained phytoavailable. To be protective of human health, site-specific risk assessments and soil guideline derivations for residential settings with vegetable gardens need to consider the produce consumption pathway.

text: Uptake of ΣDDT, arsenic, cadmium, copper, and lead by lettuce and radish grown in contaminated horticultural soils Horticultural soils can contain elevated concentrations of selected trace elements and organochlorine pesticides as a result of long-term use of agrichemicals and soil amendments. A glasshouse study was undertaken to assess the uptake of weathered ΣDDT {sum of the p,p′- and o,p-isomers of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane], DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] and DDD[1,1-dichloro-2,2-bis(p-chlorophenyl)ethane]}, arsenic (As), cadmium (Cd), copper (Cu), and lead (Pb) residues by lettuce (Lactuca sativa) and radish (Raphanus sativus) from field-aged New Zealand horticultural soils. Concentrations of ΣDDT, DDT, DDE, Cd, Cu, and Pb in lettuce increased with increasing soil concentrations. In radish, similar relationships were observed for ΣDDT, DDE, and Cu. The bioaccumulation factors were less than 1 with the exception of Cd and decreased with increasing soil concentrations. Lettuce Cd concentrations for plants grown on four out of 10 assayed soils were equivalent to or exceeded the New Zealand food standard for leafy vegetables of 0.1 mg kg−1 fresh weight. Concentrations of As, Pb, and ΣDDT did not exceed available food standards. Overall, these results demonstrate that aged residues of ΣDDT, As, Cd, Cu, and Pb in horticultural soils have remained phytoavailable. To be protective of human health, site-specific risk assessments and soil guideline derivations for residential settings with vegetable gardens need to consider the produce consumption pathway.

year: 2008

title: "Thereness": Implications of Heidegger's "presence" for Māori

authors: Mika, Carl Te Hira

abstract: For Māori, the philosophical consequences of colonization are a hugely important issue, due to both the subtlety and the omnipresence of Western metaphysics. In this article I refer to the “meta-physics of presence” through one major Western thinker—Martin Heidegger—who identified “presence” as a problem for the West. He proposes that the metaphysics of presence underpins every perception in the West and that it is the fundamental mistake of philosophers since Plato but becoming ascendant with Aristotle. I identify the points of relevance within their claims and refer them to a Māori understanding of absence. I also consider the more affective nature of Western presence, which Heidegger refers to but which must be theorized by Māori. In the first instance I place particular emphasis on the ironies implicit in writing about metaphysics for the Māori writer in the academy and for the things being represented in that writing. Finally, the metaphysics of presence opens up possibilities for its own instability; this Heideggerean “saving power” is discussed in Māori terms.

text: "Thereness": Implications of Heidegger's "presence" for Māori For Māori, the philosophical consequences of colonization are a hugely important issue, due to both the subtlety and the omnipresence of Western metaphysics. In this article I refer to the “meta-physics of presence” through one major Western thinker—Martin Heidegger—who identified “presence” as a problem for the West. He proposes that the metaphysics of presence underpins every perception in the West and that it is the fundamental mistake of philosophers since Plato but becoming ascendant with Aristotle. I identify the points of relevance within their claims and refer them to a Māori understanding of absence. I also consider the more affective nature of Western presence, which Heidegger refers to but which must be theorized by Māori. In the first instance I place particular emphasis on the ironies implicit in writing about metaphysics for the Māori writer in the academy and for the things being represented in that writing. Finally, the metaphysics of presence opens up possibilities for its own instability; this Heideggerean “saving power” is discussed in Māori terms.

year: 2015