pulse technique
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Fuel ◽  
2022 ◽  
Vol 314 ◽  
pp. 123066
Author(s):  
Xiaodong Huo ◽  
Weiran Zuo ◽  
Fengnian Shi ◽  
Wei Huang

2021 ◽  
Author(s):  
Jimena Gómez ◽  
Alberto Casal ◽  
Martin Do Carmo ◽  
Soledad Orcasberro ◽  
Pablo Soca ◽  
...  

Abstract The energy partitioning between total heat production (HP) and retained energy (RE) on the efficiency of energy use was evaluated throughout the annual production cycle (gestation-lactation) of 46 multiparous beef cows grazing on two herbage allowances (HA) of Campos grassland (4 vs. 7 kg dry matter/kg body weight; BW; LO vs. HI). Total RE was greater (P < 0.01) for HI than LO cows and presented minimum values during early gestation and maximum values during early lactation associated to the greater (P = 0.02) RE-milk in the former ones. Whole-animal HP, estimated by the heart rate-O2 pulse technique, and cow metabolized energy (ME) intake did not differ between HA treatments, but relative to BW0.75, HP was greater (P = 0.04) for LO than HI cows. Total HP and ME intake were minimum in gestation and maximum in early lactation and ME intake was greater during early lactation for HI than LO cows, and per unit of BW0.75, tended (P < 0.10) to be less for HI than LO cows in winter. The energy efficiency of the annual cycle was not affected by treatments (0.19 vs. 0.12 ± 0.02 for HI and LO respectively; P > 0.10) and there were no differences between treatments in terms of grams of calf per MJ of ME intake (P > 0.10). Management of grazing intensity of Campos grasslands with high herbage allowance improved energy balance of the beef cow-calf system through partitioning of cow ME intake towards RE instead of maintenance.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jinling Yan ◽  
Yongli Liu ◽  
Ruifen Jiao ◽  
Meixiang Li ◽  
Liqin Zhao

The study aims to explore the effect of low-frequency electric pulse technique combined with carboprost methylate suppositories on recovery of gastrointestinal function and postoperative complications of patients with scarred uterus undergoing secondary cesarean section (C-section). The clinical data of 120 patients with scarred uterus undergoing secondary C-section treated in our hospital from February 2019 to February 2020 were retrospectively analyzed, and the patients were equally divided into experimental and control groups according to their admission order, where each group included 60 patients. After the operation, patients in the control group received routine nursing and conducted breastfeeding, and carboprost methylate suppositories were used for postoperative hemostasis. Those in the experimental group received low-frequency electric pulse technique for comprehensive treatment to compare their coagulation function indicators, recovery of gastrointestinal function, incidence rates of postoperative complications, and involution of uterus. No significant between-group differences in patients’ general information such as gestational weeks, gravidity, and number of times receiving C-section were observed ( P > 0.05 ). Compared with the control group after the operation, patients in the experimental group obtained significantly better coagulation function indicators ( P < 0.001 ) and presented better gastrointestinal function recovery ( P < 0.001 ), significantly lower incidence rates of postpartum hemorrhage, retention of urine, deep venous thrombosis of lower limb, rupture of uterus, and endometrial cavity fluid ( P < 0.05 ), and significantly better involution of uterus ( P < 0.001 ). In conclusion, combining low-frequency electric pulse technique with carboprost methylate suppositories can lower the incidence rates of postoperative complications for patients with scarred uterus undergoing secondary C-section, improve their coagulation function, promote the recovery of gastrointestinal function, and present the desirable involution of uterus, which should be promoted in practice.


Author(s):  
Eric W. Schulz ◽  
Matthias Wagner ◽  
Holger Schubert ◽  
Wenqi Zhang ◽  
Bharat Balasubramanian ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4657
Author(s):  
Wioletta Raczkiewicz ◽  
Peter Koteš ◽  
Petr Konečný

The concrete cover is the basic protection of the reinforcement against the influence of external factors that may lead to its corrosion. Its effectiveness depends mainly on the composition of the concrete mix, including the cement used. Depending on external environmental factors that may aggressively affect the structure, various types of cements and concrete admixtures are recommended. The paper presents the results of tests that allow us to assess the effect of the type of cement used and the air-entraining agent on the effectiveness of the concrete cover as a layer protecting the reinforcement against corrosion. In order to initiate the corrosion process, the reinforced concrete specimens were subjected to cycles of freezing and thawing in a sodium chloride solution. The degree of advancement of the corrosion process was investigated using the electrochemical galvanostatic pulse technique. Additionally, the microstructure of specimens taken from the cover was observed under a scanning electron microscope. The research has shown that in the situation of simultaneous action of chloride ions and freezing cycles, in order to effectively protect the reinforcement against corrosion, the application of both blast-furnace slag cement and an air-entraining agent performed the best.


Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1821
Author(s):  
Juan F. Cisneros ◽  
Manuel Raul Pelaez-Samaniego ◽  
Verónica Pinos ◽  
Ingmar Nopens ◽  
Andrés Alvarado

Residence time distribution (RTD) curves play an essential role in the hydraulic characterization of reactors. Current approaches for obtaining RTD curves in laboratory-scale reactors are time-consuming and subject to large errors. Thus, automated systems to obtain RTD curves in laboratory-scale reactors are of great interest for reducing experimental errors due to human interaction, minimizing experimentation costs, and continuously obtaining experimental data. An automated system for obtaining RTD curves in laboratory-scale reactors was designed, built, and tested in this work. During the tests conducted in a cylindrical upflow anaerobic sludge blanket (UASB) reactor, the system worked properly using the stimulus–response pulse technique with sodium chloride as a tracer. Four main factors were found to affect the representativeness of the RTD curves: flow stabilization time, test water conductivity, temperature, and surface tension. A discussion on these factors and the corresponding solutions is presented. The RTD curves of the UASB reactor are left-skewed with a typical tank reactor’s flow shape with channeling and dead zones. A transitory flow behavior was evidenced in the reactor, which indicates the influence of internal turbulent flow structures. The system proposed herein is expected to help study the hydraulics of reactors using laboratory-scale models more efficiently.


2021 ◽  
Author(s):  
Sen Lu

&lt;p&gt;Soil thermal conductivity (&amp;#955;) is an important physical property in land surface parameterization. The soil thermal conductivity (&amp;#955;) and matric suction of soil water (h, the negative of matric potential) relationship has been widely used in land surface models for estimating soil temperature and heat flux following the McCumber and Pielke (1981, MP81) &amp;#955;-h model. However, few datasets are available for evaluating the accuracy and feasibility of the MP81 &amp;#955;-h model under various soil and moisture conditions. In this study, we developed a new &amp;#955;-h model and compared its performance with that of the MP81 model using measurements on 18 soils with a wide range of textures, water contents and bulk densities. The heat pulse technique was used to measure &amp;#955;, and the suction table, micro-tensiometers, pressure plate device, and the dew point potentiometer were applied to obtain soil water retention curves at the appropriate suction ranges. In the range of pF (the common logarithm of h in cm)&amp;#8804;3, the &amp;#955;-h relationships were highly nonlinear and varied strongly with soil texture and bulk density. In the dry range (i.e., pF &gt; 3), there existed a universal &amp;#955;-h relationship for all soil textures and bulk densities, and an exponential function was established to describe the relationship. Independent evaluations using &amp;#955;-h data on five intact soil samples showed that the new model produced accurate &amp;#955; data from pF values with root mean square errors (RMSE) with the range of 0.03&amp;#8211;0.18Wm&amp;#8722;1 K&amp;#8722;1. While, large errors (RMSEs within 0.17&amp;#8211;0.36Wm&amp;#8722;1 K&amp;#8722;1) were observed with &amp;#955; estimates from the MP81 model.&amp;#160;&lt;/p&gt;


2021 ◽  
Author(s):  
Sen Lu

&lt;p&gt;The soil thermal conductivity (&amp;#955;) and matric suction of soil water (h, the negative of matric potential) relationship has been widely used in land surface models for estimating soil temperature and heat flux following the McCumber and Pielke (1981, MP81) &amp;#955;-h model. However, few datasets are available for evaluating the accuracy and feasibility of the MP81 &amp;#955;-h model under various soil and moisture conditions. In this study, we developed a new &amp;#955;-h model and compared its performance with that of the MP81 model using measurements on 18 soils with a wide range of textures, water contents and bulk densities. The heat pulse technique was used to measure &amp;#955;, and the suction table, micro-tensiometers, pressure plate device, and the dew point potentiometer were applied to obtain soil water retention curves at the appropriate suction ranges. In the range of pF (the common logarithm of h in cm)&amp;#8804;3, the &amp;#955;-h relationships were highly nonlinear and varied strongly with soil texture and bulk density. In the dry range (i.e., pF &gt; 3), there existed a universal &amp;#955;-h relationship for all soil textures and bulk densities, and an exponential function was established to describe the relationship. Independent evaluations using &amp;#955;-h data on five intact soil samples showed that the new model produced accurate &amp;#955; data from pF values with root mean square errors (RMSE) with the range of 0.03&amp;#8211;0.18W m&lt;sup&gt;&amp;#8722;1&lt;/sup&gt; K&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;. While, large errors (RMSEs within 0.17&amp;#8211;0.36W m&lt;sup&gt;&amp;#8722;1&lt;/sup&gt; K&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;) were observed with &amp;#955; estimates from the MP81 model.&amp;#160;&lt;/p&gt;


Instruments ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 12
Author(s):  
Hannes C. Gottschalk ◽  
Taija L. Fischer ◽  
Volker Meyer ◽  
Reinhard Hildebrandt ◽  
Ulrich Schmitt ◽  
...  

Fourier transform infrared (FTIR) absorption spectroscopy of cold molecules and clusters in supersonic slit jet expansions complements and extends more sensitive action spectroscopy techniques and provides important reference data for the latter. We describe how its major drawback, large substance and carrier gas consumption, can be alleviated by one to two orders of magnitude via direct and continuous recycling of the gas mixture. This is achieved by a combination of dry rotary lobe and screw pump compression. The signal-to-noise ratio is boosted by the established buffered giant gas pulse technique with full interferogram synchronization. The buildup of water impurities typically limits the recycling gain, but is turned into a feature for the study of hydrate complexes of volatile molecules. Continuous operation with a single gas filling over several days becomes practical and useful. Decadic absorbances in the low ppm range are detectable and the mid infrared range can be recorded simultaneously with the near infrared. The less straightforward hydration number assignment of spectral features in direct absorption spectroscopy is supported by a gradual water buildup at a rate of less than 0.5 mg/h. A recent reassignment proposal for the water dimer OH stretching spectrum is refuted and vibrational spectra of vacuum-isolated 18O-water clusters are presented for the first time. Methanol docking on asymmetric ketones is used to illustrate the advantages and limitations of the recycling concept. Previous assignments of the hydrate complex of 1-phenylethanol are confirmed. Additional features of the setup await testing and refinement, but the recycling technique already substantially widens the applicability of direct absorption spectroscopy of neutral molecular clusters. It may be attractive for other high-throughput jet spectrometers.


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