High performance of flow-type one-compartment hydrogen peroxide fuel cell using buckypaper and narrow fuel pathway in physiological condition

Flow-type membraneless hydrogen peroxide fuel cell (HPFC) having high power density is fabricated using buckypaper (BP) based electrodes and eddy-inducing cell structure to use low concentrated H2O2 fuel. Benefiting from...

Fuzzy Regulator for Two-Phase Gas–Liquid Pipe Flows Control

The paper presents an intelligent module to control dynamic two-phase gas–liquid mixtures pipelines flow processes. The module is intelligent because it uses the algorithm based on AI methods, namely, fuzzy logic inference, to build the fuzzy regulator concept. The developed modification has allowed to design and implement the black-box type regulator. Therefore, it is not required to determine any of the complicated computer models of the flow rig, which is unfortunately necessary when using the classic regulators. The inputs of the regulator are four linguistic variables that are decomposed into two classes and two methods of fuzzification. The first input class describes the current values of gas and liquid pipe flows, which at the same time are the controlled values manipulated to generate desired flow type. The second class of the input signals contains a current flow state, namely, its name and the name preferred by the operator flow type. This approach improves the control accuracy since the given flow type can be generated with different gas and liquid volume fractions. Those values can be optimized by knowing the current flow type. Moreover, the fuzzification algorithm used for the input signals included in the first-class covers the current crisp signal value and its trend making the inference more accurate and resistant to slight measurement system inaccuracy. This approach of defined input signals in such environments is used for the first time. Considering all mentioned methods, it is possible to generate the desired flow type by manipulating the system input signals by minimum required values. Furthermore, a flow type can be changed by adjusting only one of the input signals. As an output of the inference process, two linguistic values are received, which are fuzzified adjustment values of the liquid pump and gas flow meter. The regulator looks to be universal, and it can be adopted by multiple test and production rigs. Moreover, once configured with a dedicated rig, it can be easily operated by the non (domain) technical staff. The usage of fuzzy terms makes understanding both the control strategy working principles and the obtained results easy.

Spatial analysis for crowds in multi-directional flows based on large-scale experiments

In this paper, spatial analysis for the nearest neighbors is performed in the unidirectional, bidirectional and crossing flows. Based on the intended direction given in the experiment, different types of neighbors such as U-ped (neighbor with the same intended direction), B-ped (neighbor with the opposite intended direction) and C-ped (neighbor with the intersecting intended direction) are defined. The preferable positions of these neighbors during movement are investigated under various conditions. The spatial relation is quantified by calculating the distance and angle between the reference pedestrian and neighbors. The results indicate that the distribution of neighbors is closely related to the neighbor’s order, crowd density, neighbor type and flow type. Furthermore, the reasons that result in these distributions for different neighbors are explored. Finally neighbor distributions for different flows are compared and the implications of this research are discussed. The spatial analysis sheds new light on the study of pedestrian dynamics in a different perspective, which can help to develop and validate crowd models in the future.

Disain dan Uji Kinerja Pendingin Evaporatif Tipe Aliran Searah Menggunakan CFD (Computational Fluid Dynamics)

After harvesting, fruits will change due to physiological, physical, chemical, and microbiological influences, and they are living materials. Therefore, it is necessary to know how to harvest and handle fresh fruits and their storage conditions to handle the fruits after harvesting so that the quality of the products can be maintained. One of the first treatments in the fruit cold chain is evaporative cooling. In order to get an evaporative cooling system that has an even temperature distribution, it is necessary to make a spatial model when designing an evaporative cooling system using CFD (Computational Fluid Dynamics). The objectives of this research are: (1) design of direct flow type evaporative cooling systems and (2) test the performance of direct flow type evaporative coolers. This research method uses design methods, experiments, and computer simulations. The results showed the performance of the evaporative cooler system in the scenario with the roof on, the highest effectiveness value was 1.198, the highest approximation value was 2.832, and the highest range value was 4.589. In the scenario without a roof on the evaporative cooler system, the highest effectiveness value was 1.767, the highest approach value was 2.139, and the highest range value was 4.835. The CFD analysis in the scenario with a roof had the highest temperature value of 25.9 ° C and the lowest temperature of 21.9 ° C, while the CFD analysis in the scenario without roof had the highest temperature of 23.7 ° C and the lowest temperature of 20.4 ° C. Keywords: CFD, direct flow type, evaporative cooler, quality, fruit

The use of microfluidic hardware in the synthesis of oligohexamethylene guanidine derivatives

Objectives. To develop a method for the microfluidic synthesis of oligohexamethylene guanidine salts in a flow-type reactor and to evaluate its effectiveness in relation to the synthesis in a traditional capacitive reactor and compare the purities of products obtained by these methods.Methods. The synthesis of oligohexamethylene guanidine bihydrocarbonate (OHMG-BHC) was done using microfluidic hardware and the classical approach in volume. The purity and structure of the resulting product were confirmed by 13C NMR spectroscopy and high-performance liquid chromatography (HPLC).Results. The 13C NMR spectrum of OHMG-BHC in classical bulk synthesis demonstrates that the product is unbranched and contains additionally unidentifiable impurities, in contrast to the sample obtained by the microfluidic method. Furthermore, the HPLC analysis showed that the OHMG-BHC sample synthesized using microfluidic technology has a 1.5-fold lower content than the initial monomers.Conclusions. The advantage of synthesizing OHMG-BHC in a flow-type reactor compared to the traditional method of synthesis in volume is demonstrated since a product with a higher degree of purity is obtained.