Evolution of Pneumatic Tsunami Simulators–From Concept to Proven Experimental Technique

This paper describes the evolution through three generations of pneumatic Tsunami Simulators for physical model tests of realistic tsunami. The pneumatic method, originally developed for tidal modeling in the Fifties, has been modernized to generate extraordinarily long waves in a controlled manner, with accurate reproduction of recorded free-surface tsunami field data. The paper describes how the simulator designs were developed and how they performed in the laboratory. Example results are presented from selected research studies that have validated their performance and then used to quantify tsunami effects. Having described each of the first, second, and third generation Tsunami Simulators, the paper discusses how to calibrate the wave generation control to model tsunami with model periods 20–240 s duration (equivalent to 2–20 min duration in prototype at 1:50 scale), many of which are far too long to “fit into the test flume.” The evolution of a composite approach to wave calibration is described with examples from second and third generation devices, demonstrated by successful simulation of both the 2004 Boxing Day, and the 2011 Great Eastern Japan (Tohoku) Tsunami at 1:50 scale.

Accuracy of the pneumatic method for estimating xylem vulnerability to embolism in temperate diffuse-porous tree species

SummaryThe increasing frequency of global change-type droughts has created a need for fast, accurate and widely applicable techniques for estimating xylem embolism resistance to improve forecasts of future forest changes.We used data from 12 diffuse-porous temperate tree species covering a wide range of xylem safety to compare the pneumatic and flow-centrifuge method for constructing xylem vulnerability curves. We evaluated the agreement between parameters estimated with both methods and the sensitivity of pneumatic measurements to the measurement duration.The agreement between xylem water potentials at 50% air discharged (PAD) estimated with the Pneumatron and 50% loss of hydraulic conductivity (PLC) estimated with the flow-centrifuge method was high (mean signed deviation: 0.12 MPa, Pearson correlation: 0.96 after 15 sec of gas extraction). However, the relation between the estimated slopes was more variable, resulting in lower agreement in xylem water potential at 12% and 88% PAD/PLC. All parameters were sensitive to the duration of the pneumatic measurement, with highest overall agreement between methods after 16 sec.We conclude that, if applied correctly, the pneumatic method enables fast and inexpensive estimations of embolism resistance for a wide range of temperate, diffuse-porous species, which makes it attractive for predicting plant performance under climate change.

A Unit Pipe Pneumatic model to simulate gas kinetics during measurements of embolism in excised angiosperm xylem

The Pneumatic method has been introduced to quantify embolism resistance in plant xylem of various organs. Despite striking similarity in vulnerability curves between the Pneumatic and hydraulic methods, a modeling approach is highly needed to demonstrate that xylem embolism resistance can be accurately quantified based on gas diffusion kinetics.A Unit Pipe Pneumatic (UPPn) model was developed to estimate gas diffusion from intact conduits, which were axially interconnected by interconduit pit membranes. The physical laws used included Fick’s law for diffusion, Henry’s law for gas concentration partitioning between liquid and gas phases at equilibrium, and the ideal gas law.The UPPn model showed that 91% of the extracted gas came from the first two series of embolized, intact conduits, and only 9% from the aqueous phase after 15 s of simulation. Embolism resistance measured with a Pneumatic apparatus was systematically overestimated by 2 to 17%, corresponding to a typical measuring error of 0.11 MPa for P50 (the water potential equivalent to 50% of the maximum amount of gas extracted).Because results from the UPPn model are supported by experimental evidence, there is a good theoretical and experimental basis for applying the pneumatic method to research on embolism resistance of angiosperms.

No gas source, no problem: proximity to pre-existing embolism and segmentation affect embolism spreading in angiosperm xylem by gas diffusion

Embolism spreading in dehydrating angiosperm xylem is driven by gas movement between embolised and sap-filled conduits. Here, we examine how proximity to pre-existing embolism and hydraulic segmentation affect embolism propagation. Based on the optical method, we compared xylem embolism resistance between detached leaves and leaves attached to branches, and between intact leaves and leaves with cut minor veins for six species. Moreover, we directly compared the optical and pneumatic method on detached leaves. Embolism resistance of detached leaves was significantly lower than leaves attached to stems, except for two species with all vessels ending in their petioles. Cutting of minor veins showed limited embolism spreading in minor veins near the cuts prior to major veins. Moreover, there was strong agreement in embolism resistance between the optical and pneumatic method, with minor differences occurring during early stages of embolism formation. We conclude that embolism resistance may represent a relative trait, depending on the proximity and connectivity to pre-existing embolism as a gas source. Since embolism formation may not rely on a certain pressure difference threshold between functional and embolised conduits, we suggest that embolism is facilitated by pressure-driven gas diffusion, while hydraulic segmentation can prevent embolism propagation by reducing gas diffusion.

Research of the stressed state in the sections of trees’ trunks in a pneumatic method for fruit harvesting

The method of calculating the strength of fruit tree trunks during operation of a pneumatic fruit shaker is presented. Taking into account the technological and design parameters of the pneumatic shaker, the law of changing the bending moment along the length of the tree trunk is derived, the required angle of rotation of the fan nozzle of the pneumatic shaker is determined.

A Comparison of Pneumatic and Hand Stripping of Whitefish (Coregonus lavaretus) Eggs for Artificial Reproduction

We describe the technique of pneumatic stripping of whitefish (Coregonus lavaretus) eggs with the use of oxygen, nitrogen, and air. Eggs obtained via the traditional method (by pressing the abdominal surfaces) served as a control group. It was established that the gas flow rate during pneumatic stripping should not exceed 0.5 L∙min−1, since higher air flow resulted in increased post-spawning mortality. The pneumatic stripping method of egg collection was no faster than hand stripping; however, the time required per female was more consistent. It was found that the pH of the ovarian fluid obtained during hand and pneumatic stripping was not related to the success rate of fertilization. Pneumatic stripping resulted in a higher quality of collected eggs and a higher and more consistent hatching rate as compared with the hand-stripped samples, regardless of the gas used. The results presented here lead us to recommend the pneumatic method for obtaining eggs from whitefish, since it is a simple, reproducible method and improves the reproductive performance and developmental success of the fish eggs.

DEPENDENCE OF ELECTROSTATIC POTENTIAL ON THE TRANSPORTATION SPEED DURING AIR CHARGING

The wide use of pneumatic method of loading and portage of granular explosives (ВВ) at the conduct of mountain works specifies on the necessity of researches of defects concomitant to this method: namely an origin of electrification in a charge hose. Electric potential and charge are the basic parameters of the energy distinguished at a digit, the amount of warmth of thatgoes to the warming-up of VV. In the total, knowing the minimum temperatures of selfignition of a erodredges, it is possible to control the size ofelectric charge and exceeding of that conduces to the unplanned explosion.

Влияние способа перемешивания бродящей среды на накопление биомассы и выход спирта

В статье представлены результаты сравнительных исследований динамики физиологического состояния дрожжевой биомассы и накопления спирта при сбраживании ячменного сусла (с массовой долей сухих веществ 21-22) с использованием препарата АСД DistilaMax GW при различных способах перемешивания бродящей среды. Показано, что использование пневматического способа перемешивания способствует большему накоплению биомассы жизнеспособных клеток, по сравнению с механическим перемешиванием на 5, при реализации брожения без перемешивания на 7,1 . В отношении выхода спирта, как механический, так и пневматический способы перемешивания бродящий среды, эффективнее на 9 относительно осуществления процесса брожения без перемешивания. Учитывая, что стоимость оборудования для пневматического перемешивания дешевле, чем для механического, результаты исследований дают основания предполагать экономические преимущества получения спирта из зернового сырья, при использовании пневматического способа перемешивания бродящей среды.The study compared the dynamics of yeast biomass physiological state and alcohol accumulation during barley wort fermentation (with dry solids weight ratio at 21-22) using the ADY DistilaMax GW preparation and various fermenting medium mixing methods. The paper summarizes the study findings. It has been demonstrated that pneumatic mixing method ensures a 5 increase in the accumulation of viable cells biomass as compared to mechanical mixing method, and a 7.1 increase when no mixing was performed during fermentation. As to the alcohol output, both mechanical and pneumatic fermenting medium mixing methods demonstrated a 9 increase in the effectiveness when fermentation was conducted without mixing. Considering the fact that pneumatic mixing equipment is cheaper than the mechanical one, the research findings suggest economic advantages of grain alcohol production using pneumatic method for mixing of the fermenting medium.