Appraisal of Cumulative Volume of Biogas Produced from Water Hyacinth and Selected Animal Dungs Co-Digestion Mixes

Water Hyancinth (WH) was co-digested with different mix ratios of poultry manure (PM), cow dung (CD) and pig dung (PD). A comparative analysis of the cumulative volume of gas produced from the different co-digestion mixes was carried out. The monitoring of the digestion process was done on a daily basis for a retention period of 40 days. The efficacy of the digestion process as well as the best mix ratio of water hyacinth to the different animal dungs was also evaluated in terms of the volume of gas produced. A rotameter with a capacity of 0.1-1L/Min equipped with a measuring tube was used for the gas flow measurements. From the results obtained the best mix of the PD-aided WH digestion is 3 WH:7 PD while CD - aided WH digestion is 2 WH:8 CD and PM-aided WH digestion is 2 WH: 8 PM. The study also revealed that the PM-aided WH mix produced more biogas compared to the CD-aided and PD-aided WH digestion mix.

Quantifying bite force in coexisting tayassuids and feral suids: a comparison between morphometric functional proxies and in vivo measurements

Background Measuring mammals’ bite force in laboratory conditions is not a simple task, let alone on wild medium-sized mammals in the field. Thus, morphometric-proxies are usually used to infer morphofunctional properties of musculoskeletal features. For instance, the study of bite force-indexes suggests that different capacities to crack food items reduce the competition between coexistent collared and white-lipped peccaries (Pecari tajacu and Tayassu pecari). The presence of exotic feral hogs (Sus scrofa) in peccaries’ endemic areas gives rise to new ecological interactions between them. An example is the Brazilian Pantanal wetland, where ecomorphological mechanisms may play a role in their ecological relations. Taking this scenario as a case of study, we aimed to verify if the morphometric-proxies are de facto reliable tools, by comparing bite forces-indexes with the in vivo bite forces of these species. Methods We captured 21 collared and white-lipped peccaries and feral hogs in the Brazilian Pantanal to assess their bite force at first molar. The Bite Force Measuring Tube (BiTu) is a robust and simple mechanical device designed to be used in field conditions. Only 11 individuals successfully bit the BiTu before being released. Their body measurements were compared and correlated with their bite force. The in vivo bite forces were compared with bite force-indexes of two papers based on independent morphometric methods and datasets: Sicuro & Oliveira (2002) used classic morphometrics to infer the bite forces of these three species in the Brazilian Pantanal, and Hendges et al. (2019) used geometric morphometrics to compare bite forces-indexes and feeding habits of the extant peccary species. The results of all species were standardized (Z-curves) according to each method. Doing so, we obtained comparable dimensionless comparable values but maintaining the differences between them. Results The morphometric-proxies-based studies presented similar results: collared peccaries present weaker bites than white-lipped peccaries and feral hogs, while these two species presented no significant differences in their bite force-indexes. The in vivo bite force results suggest the same relations predicted by the morphometric models, including the high variation among the feral hogs. We found a significant correlation between the individuals’ weight (kg) and their actual bite force (N) but no significant correlations with the head length. Conclusions The BiTu proved to be a functional and low-cost tool to measure bite force in field conditions. The in vivo results presented a good correspondence with the predictions based on morphometric-proxies by Sicuro & Oliveira (2002) and Hendges et al. (2019). The results denote that these studies succeed in capturing the biomechanical signal of the three species’ skull-jaw systems. This empirical validation confirms that these morphometric-proxies analyses are reliable methods to ecomorphological and evolutionary inferences.

Estimation and experimental test of the sound-absorption coefficient of a pin-holder structure (Case of sound waves incidence upon the side surfaces of a group of cylinders)

In this study, we conducted theoretical analyses and experiments related to the acoustic characteristics of the situation where sound waves are incident upon the side surfaces of a group of cylinders forming a pin-holder structure. The sound-absorption coefficient, entering its clearance between cylinders through the geometrical dimension of the clearance or the physical property of gas, was calculated. In the analytical model, the gap part of the pin-holder structure was divided into elements and approximated as a gap surrounded by two parallel planes. The characteristic impedance and propagation constant of the approximate gap were obtained and treated as one-dimensional transfer matrices; the sound-absorption coefficient was then calculated using the transfer-matrix method. The calculated value was compared to that obtained in an experiment with a sample prepared using a 3D printer; the sound-absorption coefficient was measured using a 2-microphone impedance-measuring tube. We attempted to make a simple yet accurate estimation of sound-absorption coefficient using these procedures. Our theoretical values displayed a similar tendency to that obtained by experiment.

EFFECTS OF BOUNDARY CONDITIONS ON A BOSCH-TYPE INJECTION RATE METER

Spread and evolution of Common Rail (CR) injection systems enable to influence injection events more efficiently than ever, while injection mass flow rate during an injection event crucially affects the combustion process. A measurement device based on the work of Bosch was set up, and measurements were made with different boundary conditions to explore the capabilities of the measurement system and to validate a detailed model of a CR injector. The main finding of this research work is, that orifice size had no noticeable effect on the measured injection rate traces, while it was stated in the original work that a small orifice is needed to terminate the measuring tube to maintain stable measurement conditions. Moreover, the backpressure level in the measuring system has a significant effect on the measured injection traces. If pressure in the measuring tube is low, gradient at the injection rate rise is lower, while if the pressure is comparable with that of a combustion chamber maximal compression pressure, measurement of higher doses is unaccomplishable due to the long pressure decrease time in the measuring tube after the end of the injection. Based on the results of the investigation, it can be stated that the Bosch-type injection rate measurement method does not give back the exact injection rate shape, a supplementing method would be necessary to calculate real nozzle flow rate.

Each-Phase Metering with Gas-Liquid Stratified Flow Based on the Multi-Frequency Coriolis Principle

Gas-liquid two-phase flows generally have the characteristics of complex and variable flow patterns and flow rate uncertainty of each phase. The entrainment of gas increases errors of the existing non-separated multiphase metering. A novel metering method based on the multi-frequency Coriolis principle is proposed to solve the above problems. Compared to the conventional Coriolis mass flowmeter, the third-order mode of the measuring tube is used to improve the accuracy of the measurement. The influences of bubble effect and resonance effect on vibration responses in different vibrational modes were studied to determine the deviations of the apparent values of total density and mass flowrate by simulation. Simulation results with a single-frequency Coriolis flowmeter show that the maximum relative deviations of total density and total mass flowrate are −37.3% and −9.3%, respectively. Driven by different frequencies, the same two phase fluid in the measuring tube can have different responses of the primary mode and the higher vibrational modes. The vibrational responses characteristics corresponding to the first-order and third-order modes of measuring tube were selected and analyzed. Combined with advantages of high precision and multi-parameter measurement of traditional single-frequency Coriolis flowmeters, a multi-frequency correction model suitable for stratified flow was proposed. The results show that the corrected total density and mass flow deviations of gas-containing fluid are within ±4% and ±3%, respectively, which are significantly reduced. Corrected flowrate deviations of the gas-phase and liquid-phase are ±9.1% and ±7.2%, correspondingly, which also meet the metering requirements of the wellhead.

Total Temperature Measurement of Gas at Microtube Outlet

This paper describes experimental results on the total temperature measurement of gas at the microtube exit. In order to measure the total temperature at the microtube outlet, two total temperature measuring devices with different structures were fabricated. One is six plastic baffle plates embedded inside with a thermally insulated exterior foamed polystyrene tube. The other is two glass fiber thimbles embedded inside it. The gas velocity was reduced by the plastic plates and the glass fiber thimbles, and the kinetic energy was converted into thermal energy. The fundamental premise of the total temperature measurement is the Joule Thomson effect present in real gases, which for a positive of the Joule Thomson coefficient involves the decrease in temperature when the gas experiences isenthalpic expansion. A PEEK microtube whose nominal inner diameter and outer diameter were 500 μmm and 1.6 mm, was used for assessing exact measurement of total temperature in the temperature measuring tube, since the thermal conductivity of the PEEK tube is very low. The measured total temperatures were compared with those obtained theoretically with the Joule Thomson coefficient and given thermodynamics properties.

Models for measuring the liquid level in thetank of rocket carrier

The models for measuring the level of a viscous incompressible fluid in the tank by liquid level in the measuring tube are considered. The tank is in the gravitational field and the level of liquid inside varies according to some law. The base model is the first boundary value problem for nonlinear integro-differential equation of parabolic type. The empirical model is Cauchy problem for nonlinear ordinary second order differential equation. It is numerically founded that for linear time-decreasing level of fluid tank fluid level in the measuring tube oscillates about level in the tank with damping amplitude.