This study presents a thermo-economic assessment of three low-global-warming-potential (GWP) substitutes, R1233zd(E), R1234ze(Z) and R1234ze(E), for R245fa used in organic Rankine cycle (ORC) systems, considering two models with different heat sources. The exhaust heat from a diesel generator is served as heat source of Model I, while the waste heat of exhaust and jacket cooling water are used as heat source of Model II. It is noted that the working pressure of R1234ze(E) is much higher than that of R1233zd(E), R1234ze(Z) and R245fa in a fixed evaporation-temperature range. Furthermore, the system using R1234ze(E) has the minimum net power output for Model I, while it turns into the maximum net power output for Model II. In addition, both R1234ze(Z) and R1233zd(E) can be used as good alternative working fluids for R245fa because R1234ze(Z), R1233zd(E) and R245fa have close working pressures, maximum net power outputs, and minimum levelized energy costs. Compared to Model I, LEC min of R1233ed(E) and R1234ze(Z) are reduced by 10.8 % and 9.9 % and PB min of R1233ed(E) and R1234ze(Z) are reduced by 11.5 % and 10.1 %, respectively, in Model II. However, R1233zd(E) has the highest minimum payback period for both Model I and Model II among the four working fluids investigated.

The increasing spread of ragworts is observed with concern. Ragworts like tansy ragwort (Jacobaea vulgaris Gaertn.) or marsh ragwort (J. aquatica) contain pyrrolizidine alkaloids (PA) which may induce hepatotoxic effects. Grazing animals usually avoid ragworts if their pasture management is appropriate. Preserved feed prepared from ragworts contaminated meadows may, however, lead to a significant exposure to PA. Previous studies on toxicity of PA for dairy cows revealed inconsistent results due to feeding ragwort plant material which was associated with heterogeneous PA exposure and thus failed to conclusively deduce critical PA doses. Therefore, the aim of the present study was to expose dairy cows (n = 4 per group) in a short-term scenario for 28 days with increasing PA doses (PA1: 0.47 mg PA/kg body weight (BW)/day (d); PA2: 0.95 mg PA/kg BW/d; PA3: 1.91 mg PA/kg BW/d) via oral administration by gavage of a defined PA-extract. While group PA3 was dosed with the PA-extract alone, groups PA2 and PA1 received PA-extracts blended in similar volumes with molasses to provide comparable amounts of sugar. Additionally, two control groups were treated either with water (CONWater) or with molasses (CONMolasses) to assess the effects of sugar without PA interference. While clinical traits including dry matter intake, milking performance, rectal body temperature, ruminal activity and body condition score (BCS) were not influenced by PA exposure, activities of enzymes indicative for liver damages, such as gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST) and glutamate dehydrogenase (GLDH), increased significantly over time at an exposure of 1.91 mg total PA/kg BW/d.

Recently, consumers concerns towards an environmental friendly food production are growing. The dairy sector contributes to the production of important greenhouse gases such as methane. The life cycle assessment (LCA) method enables to quantify the emissions and the use of resources throughout the entire life cycle of a product. The aim of the current study was to investigate the influence of performance parameters on the level of important environmental impacts (global warming potential (GWP), freshwater eutrophication (FE), terrestrial acidification (TA) and agricultural land occupation (ALO)) associated with milk production. Therein, the environmental impacts were analyzed using LCA considering two separate datasets (total, continuous) from Northern German farms throughout the years 2004-2013. Therefore, the performance parameters determining the level of environmental impacts were identified using the partial least square method. Thereby, a differentiated analysis among regions with various soil characteristics (Heath, Hill, Marsh) was conducted additionally. Further, linear mixed models were applied to each of the environmental impact categories. Energy-corrected milk yield (ECM), ECM from roughage, feed efficiency and the use of concentrates were identified as the most important determinants of environmental impacts. In general, an increase in productivity, especially an increase in ECM per cow and an increase in the amount of ECM produced per area of agricultural land accompanied with an improvement in environmental efficiency. The type of feed used had the major impact on the level of environmental impacts, whereby both concentrates and roughage had disadvantages. These results were in line with previous studies. Although, this study provides additional information relating the most important determinants of different environmental impacts, including a differentiated consideration of the relationship between performance parameters and environmental efficiency among regions. Further analyses on specific soil characteristics and their impact on environmental efficiency are recommended. In line with the concept of eco-efficiency, useful mitigation strategies in practice need to be applied depending on individual framework conditions.

We present here a longitudinal study determining the effects of two 3 week-periods of high intensity high volume interval training (HIHVT) (90 intervals of 6 s cycling at 250% maximum power, Pmax/24 s) on a cycle ergometer. HIHVT was evaluated by comparing performance tests before and after the entire training (baseline, BSL, and endpoint, END) and between the two training sets (intermediate, INT). The mRNA expression levels of myosin heavy chain (MHC) isoforms and markers of energy metabolism were analyzed in M. vastus lateralis biopsies by quantitative real-time PCR. In incremental tests peak power (Ppeak) was increased, whereas V˙ O2peak was unaltered. Prolonged time-to-exhaustion was found in endurance tests with 65 and 80% Pmax at INT and END. No changes in blood levels of lipid metabolites were detected. Training-induced decreases of hematocrit indicate hypervolemia. A shift from slow MHCI/β to fast MHCIIa mRNA expression occurred after the first and second training set. The mRNA expression of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), a master regulator of oxidative energy metabolism, decreased after the second training set. In agreement, a significant decrease was also found for citrate synthase mRNA after the second training set, indicating reduced oxidative capacity. However, mRNA expression levels of glycolytic marker enzyme glyceraldehyde-3-phosphate dehydrogenase did not change after the first and second training set. HIHVT induced a nearly complete slow-to-fast fiber type transformation on the mRNA level, which, however, cannot account for the improvements of performance parameters. The latter might be explained by the well-known effects of hypervolemia on exercise performance.