Maternal food restriction during pregnancy affects offspring development and swimming performance in a placental live-bearing fish

How pregnant mothers allocate limited resources to different biological functions such as maintenance, somatic growth, and reproduction can have profound implications for early life development and survival of offspring. Here we examined the effects of maternal food restriction during pregnancy on offspring in the matrotrophic (i.e. mother-nourishment throughout gestation) live-bearing fish species Phalloptychus januarius (Poeciliidae). We fed pregnant females either with a ‘low-food’ or ‘high-food’ ration for six weeks and quantified the consequences for offspring size and body fat at birth and one week after birth. We further measured fast-start escape performance of offspring at birth, as well as swimming kinematics during prey capture at zero, two, and seven days after birth. We found that the length of maternal food restriction during pregnancy negatively affected offspring dry mass and lean dry mass at birth, as well as body fat gain during the first week after birth. Moreover, it impacted the locomotor performance of offspring during prey capture at, and during the first week after, birth. We did not observe an effect of food restriction on fast-start escape performance of offspring. Our study suggests that matrotrophic poeciliid fish are maladapted to unpredictably fluctuating resource environments, because sudden reductions in maternal food availability during pregnancy result in smaller offspring with slower postnatal body fat gain and an inhibition of postnatal improving swimming skills during feeding, potentially leading to lower competitive abilities after birth.

Efficient thrust enhancement by modified pitching motion

Thrust and/or efficiency of a pitching foil (mimicking a tail of swimming fish) can be enhanced by tweaking the pitching waveform. The literature, however, show that non-sinusoidal pitching waveforms can enhance either thrust or efficiency but not both simultaneously. With the knowledge and inspiration from nature, we devised and implemented a novel asymmetrical sinusoidal pitching motion that is a combination of two sinusoidal motions having periods T1 and T2 for the forward and retract strokes, respectively. The motion is represented by period ratio $\mathrm{\mathbb{T}} = {T_1}/T$ , where T = (T1 + T2)/2, with $\mathrm{\mathbb{T}} > 1.00$ giving the forward strokes (from equilibrium to extreme position) slower than the retract strokes (from extreme to equilibrium position) and vice versa. The novel pitching motion enhances both thrust and efficiency for $\mathrm{\mathbb{T}} > 1.00$ . The enhancement results from the resonance between the shear-layer roll up and the increased speed of the foil. Four swimming regimes, namely normal swimming, undesirable, floating and ideal are discussed, based on instantaneous thrust and power. The results from the novel pitching motion display similarities with those from fish locomotion (e.g. fast start, steady swimming and braking). The $\mathrm{\mathbb{T}} > 1.00$ motion in the faster stroke has the same characteristics and results as the fast start of prey to escape from a predator while $\mathrm{\mathbb{T}} < 1.00$ imitates braking locomotion. While $\mathrm{\mathbb{T}} < 1.00$ enhances the wake deflection at high amplitude-based Strouhal numbers (StA = fA/U∞, where f and A are the frequency and peak-to-peak amplitude of the pitching, respectively, and U∞ is the freestream velocity), $\mathrm{\mathbb{T}} > 1.00$ improves the wake symmetry, suppressing the wake deflection. The wake characteristics including wake width, jet velocity and vortex structures are presented and connected with $S{t_d}( = fd/{U_\infty })$ , ${A^{\ast}}( = A/d)$ and $\mathrm{\mathbb{T}}$ , where d is the maximum thickness of the foil.

Towards Continuous Primary Manufacturing Processes—Particle Design through Combined Crystallization and Particle Isolation

Integrated continuous manufacturing processes of active pharmaceutical ingredients (API) provide key benefits concerning product quality control, scale-up capability, and a reduced time-to-market. Thereby, the crystallization step, which is used in approximately 90% of API productions, mainly defines the final API properties. This study focuses on the design and operation of an integrated small-scale process combining a continuous slug flow crystallizer (SFC) with continuous particle isolation using the modular continuous vacuum screw filter (CVSF). By selective adjustment of supersaturation and undersaturation, the otherwise usual blocking could be successfully avoided in both apparatuses. It was shown that, during crystallization in an SFC, a significant crystal growth of particles (Δd50,3≈ 220 µm) is achieved, and that, during product isolation in the CVSF, the overall particle size distribution (PSD) is maintained. The residual moistures for the integrated process ranged around 2% during all experiments performed, ensuring free-flowing particles at the CVSF outlet. In summary, the integrated setup offers unique features, such as its enhanced product quality control and fast start-up behavior, providing a promising concept for integrated continuous primary manufacturing processes of APIs.

Pumped Hydroelectricity and Utility-Scale Batteries for Reserve Electricity Generation in New Zealand

<p>Non-pumped hydroelectricity-based energy storage in New Zealand has only limited potential to expand to meet projected growth in electricity demand. Seasonal variations of hydro inflows have also led to several 'dry-year' events over the last decade and dedicated fast-start 'peaker' capacity may also be required to support wind power as it approaches a 20% generation share. In this research, the New Zealand electricity industry has been surveyed in regard to the feasibility of reducing CO2-e emissions through the introduction of pumped hydroelectricity and utility-scale batteries by 2025. A desk-based review of the economic costs of these technologies has also been performed and their drivers and barriers critically assessed. Most respondents to the survey projected that peak power demand will continue to increase and this will result in new-build centralised (~150 MW) thermal reserve power sources. In New Zealand, the costs of pumped hydro and batteries are seen to be prohibitive to their introduction, even though they are almost universally assumed to be technically capable of providing renewables support and peak power adequacy. The perception of the poor economic viability of pumped hydro may, in part, be due to the relatively high capital cost estimate associated with the Manorburn-Onslow proposal (~NZ$3 billion). This research has shown, however, that smaller, 'more-internationally-representative' pumped hydro schemes, if available in NZ with low associated environmental impact, are cost-competitive with thermal peakers, especially diesel peakers. Conversely, utility-scale batteries have very high storage costs per kWh and are most likely to be used only for very high value applications where there is a strong technical advantage, such as the six-second fast instantaneous reserve.</p>

Pumped Hydroelectricity and Utility-Scale Batteries for Reserve Electricity Generation in New Zealand

<p>Non-pumped hydroelectricity-based energy storage in New Zealand has only limited potential to expand to meet projected growth in electricity demand. Seasonal variations of hydro inflows have also led to several 'dry-year' events over the last decade and dedicated fast-start 'peaker' capacity may also be required to support wind power as it approaches a 20% generation share. In this research, the New Zealand electricity industry has been surveyed in regard to the feasibility of reducing CO2-e emissions through the introduction of pumped hydroelectricity and utility-scale batteries by 2025. A desk-based review of the economic costs of these technologies has also been performed and their drivers and barriers critically assessed. Most respondents to the survey projected that peak power demand will continue to increase and this will result in new-build centralised (~150 MW) thermal reserve power sources. In New Zealand, the costs of pumped hydro and batteries are seen to be prohibitive to their introduction, even though they are almost universally assumed to be technically capable of providing renewables support and peak power adequacy. The perception of the poor economic viability of pumped hydro may, in part, be due to the relatively high capital cost estimate associated with the Manorburn-Onslow proposal (~NZ$3 billion). This research has shown, however, that smaller, 'more-internationally-representative' pumped hydro schemes, if available in NZ with low associated environmental impact, are cost-competitive with thermal peakers, especially diesel peakers. Conversely, utility-scale batteries have very high storage costs per kWh and are most likely to be used only for very high value applications where there is a strong technical advantage, such as the six-second fast instantaneous reserve.</p>

Functional Threshold Power Estimated from a 20-minute Time-trial Test is Warm-up-dependent

This study investigated the influence of different warm-up protocols on functional threshold power. Twenty-one trained cyclists (˙VO2max=60.2±6.8 ml·kg−1·min−1) performed an incremental test and four 20-min time trials preceded by different warm-up protocols. Two warm-up protocols lasted 45 min, with a 5-min time trial performed either 15 min (Traditional) or 25 min (Reverse) before the 20-min time trial. The other two warm-up protocols lasted 25 min (High Revolutions-per minute) and 10 min (Self-selected), including three fast accelerations and self-selected intensity, respectively. The power outputs achieved during the 20-min time trial preceded by the Traditional and Reverse warm-up protocols were significantly lower than the High Revolutions-per-minute and Self-selected protocols (256±30; 257±30; 270±30; 270±30 W, respectively). Participants chose a conservative pacing strategy at the onset (negative) for the Traditional and Reverse but implemented a fast-start strategy (U-shaped) for the High revolutions-per-minute and Self-selected warm-up protocols. In conclusion, 20-min time-trial performance and pacing are affected by different warm-ups. Consequently, the resultant functional threshold power may be different depending on whether the original protocol with a 5-min time trial is followed or not.

Turn-Down Capability of Ansaldo Energia's GT26

The operational flexibility of heavy-duty gas turbines is of increasing importance in today's power generation market. Fast start-up, fast loading, grid frequency support, fuel flexibility and turn-down capability are only some of the keywords that describe the challenges for GT manufacturers. This paper reports Ansaldo Energia's activities to further reduce the Minimum Environmental Load (MEL) of the GT26. The difficulties related to operation at very low loads and the solutions that were developed are explained. Furthermore, the results of engine validation tests of the new extended Low Load Operation (eLLO) and extended Low Part Load (eLPL) operation concepts are presented. The enhancement of the operational flexibility of the GT26 is in the focus of Ansaldo's development activities since many years. Its sequential combustion system is a very good basis for flexible and emission compliant operation down to very low loads. Ansaldo Energia's Low Part Load (LPL) and Low Load Operation (LLO) concepts are standard products in the GT26 flexibility portfolio and established in the market for many years. Ansaldo Energia has conducted a development project in the past two years in order to further reduce the minimum simple cycle and combined cycle loads. The extension of the LLO and LPL operating ranges and their combination into one single feature are the main targets of the project.