Papers by Keyword: Retention

Abstract: Microfluidics is an efficient technology for controlling fluid movement in microchannels at extremely low speeds. The main advantage lies in the significant reduction of samples and reagents, thereby reducing costs and analysis times. Three devices with retention systems are introduced that are manufactured through 3D printing (SLA) incorporating microchannels with variations in levels and dimensions. Fluid velocity is studied, considering factors such as channel width, length, rounding, height, and shape. The analysis of velocity along the channel reveals liquid retention at the devices' maximum point, ensuring more precise results in microdevices.

Abstract: The filtration of hexavalent chromium (Cr(VI)) presents a significant challenge in water treatment due to its toxicity and environmental impact. This study is oriented towards the development of a zeolite-based membrane for the removal of Cr(VI) ions. Flat supports are made from clay with a particle size between 160 and 250 µm and then characterized by different techniques namely FTIR, XRD, and point of zero charge (pHpzc). The clay support creates a porous structure, ideal for adsorbing Cr(VI) ions, while the LTA-type zeolite membrane offers selective permeability, through its narrow pore size, tuning the volume down on Cr(VI). Filtration experiments were conducted under a pressure of 1.0 bar, initial Cr(VI) concentration of 10^-4 M and pH = 5.4 to evaluate the efficiency and performance of the composite membrane. Results demonstrate significant reduction in Cr(VI) concentration, with a 30% and 50% retention on the clay support and the LTA-zeolite membrane respectively. The proposed methodology has the potential to create advanced water treatment systems that can effectively remove Cr(VI) pollutants from aqueous solutions, thereby challenging important environmental issues.

Abstract: In this paper, the influence of some ingredient concentrations such as SBR ratio, DCP/S, CBS/DPG accelerator, EPDM-g-AM and cord surface on mechanical, thermal aging properties and adhesion between rubber compounds and cord have been investigated. The results showed that with suitable ingredients loading such as EPDM/SBR is 85/15 phr, DCP/S is 2.0/1.5 phr and EPDM-g-AM content is 2.0 phr with respect to rubber, the vulcanizates had good mechanical properties, thermal stability and adhesion level to the zinc/copper galvanized cord. The highest tensile strength, elongation at break and pull out strength reached 18.1 MPa, 432% and 60.3 N/mm respectively, and the highest retention after thermal aging at 150°C for 168 hours was about 0.76.

Abstract: In this paper, the influence of paraffinic oil on the physical mechanical, thermal and adhesion properties of three blends of EPDM Buna EP T.6465, Keltan 5260Q and Keltan 6160 D and CIIR have been investigated. The results showed that the tensile strength values and elongation at break of keltan 5260Q/CIIR and keltan 6160 D/CIIR with 10 wt.% paraffinic oil represent the improvement of 57.8%, 57.6% and 71% to 81% respectively, compared with one without oil. The mean peel force of EPDM keltan 6260D with 10% oil loaded is about 36% and 32.5% higher than that of EPDM keltan 5260Q and EP.T 6465 blends respectively. With suitable oil content, in this case is 10% wt., the thermal resistance of keltan 5260 Q and 6160D seems to be higher than that of without processing oil and suitable for thermal resistance rubber application.

Abstract: The classical concept of diffusion characterized by Fick’s law is well suited for describing a wide class of practical problems of interest. Nevertheless, it has been observed that it is not enough to properly represent other relevant applications of practical interest. When in a system of particles their spreading is slower or faster than predicted by the classical diffusion model, such a phenomenon is referred to as anomalous diffusion. Time fractional, space fractional and even space-time fractional equations are widely used to model phenomena such as solute transport in porous media, financial modelling and cancer tumor behavior. Considering the effects of partial and temporary retention in dispersion processes a new analytical formulation was derived to simulate anomalous diffusion. The new approach leads to a fourth-order partial differential equation (PDE) and assumes the existence of two concomitant fluxes. This work investigates the behavior of the bi-flux approach in one dimensional (1D) medium evaluating the mean square displacement for different cases in order to classify the diffusion process in normal, sub-diffusive or super-diffusive.

Abstract: This paper presents the issue of computer modelling of selected anchors for overdentures and their impact on functionality and efficiency of operation of dentures. As the construction material for anchors, the traditional Ti6Al4V titanium alloy was used. Attention was paid to the varied force transfer during modelled mastication. A verification of anchors and actions: external load – dentures – retention elements – edging socket (e.g. mandible bone, maxilla bone, mucous membrane) was performed by means of MES. The performed simulation tests made it possible to choose the most optimal design of anchoring construction for overdentures in a given case.

Abstract: The use of nanoparticles with carbon dioxide foams has been proposed for enhanced oil recovery due to their robust chemical stability in harsh environment. The experimental study was performed by using nanoparticles stabilized carbon dioxide foams to study their recovery of residual oil by varying the carbon dioxide flow rates on different core samples such as sandstone and limestone. Experimental setup was divided into two different kinds of experiments which are the injection of carbon dioxide foams and the injection of nanoparticles assisted carbon dioxide foams in both sandstone and limestone core samples. For the CO₂ foam injection, it was found that limestone has higher oil recovery than sandstone rock samples with 38.67% recovery and 36.36% recovery for sandstone. With the nanoparticles assisted injection, the crude oil recovery increased to 41.82% and 45.33% for sandstone and limestone respectively. Limestone showed the higher porosity reduction at the end of experiment compared to sandstone with the porosity of 7.56% on limestone and 12.49% on sandstone respectively. This is due to the nanoparticles strongly absorbed at the limestone surfaces containing calcite component.

Abstract: Ferroelectrics are very interesting materials for nonvolatile data storage due to the fact that they deliver very low power programming operation combined with nonvolatile retention. For 60 years researchers have been inspired by these fascinating possibilities and have tried to build ferroelectric memory devices that can compete with mainstream technologies in their respective time. The progress of the current concepts is limited by the low compatibility of ferroelectrics like PZT with CMOS processing. Therefore, PZT or SBT based 1T1C ferroelectric memories are not scaling below 130 nm and 1T ferroelectric FETs based on the same materials are still struggling with low retention and very thick memory stacks. Hafnium oxide, a standard material in sub 45 nm CMOS, can show ferroelectric hysteresis with promising characteristics. By adding a few percent of silicon and annealing the films in a mechanically confined manner. Boescke et al. demonstrated ferroelectric hysteresis in hafnium oxide for the first time. Recently, a large number of dopants including Y, Al, Gd and Sr have been used to induce ferroelectricity in HfO₂. This paper reviews the current status of hafnium oxide based ferroelectrics, its application to field effect transistors and puts this approach into a wider context of earlier developments in the field.

Abstract: Purpose: For health water pack polysaccharide easy loss occurred during processing, establish a high retention rate of the processing method. Method: Chooseing slice thickness, heating time and temperature as the parameter, the water pack for steaming, boiled, Fried, baked oil heating treatment, determination of the water pack polysaccharide content, it is concluded that optimal process parameters, the retention rate of statistics. Results: The best conditions for water pack all kinds of processing method is: (1) steamed products: slice thickness of 1.6 cm, 106 °C steamed 10 mins; (2) boiled products: slice thickness of 1.2 cm, 90 °C cooked for 10 mins; (3) baked products: the slice thickness of 0.2 cm, 160 °C baking 14 mins; (4) Fried products: the slice thickness of 0.2 cm, and 150 °C the frying time of 5.5 mins. Processing products in water pack polysaccharide retention rate is as follows: Steaming > Boiled > Fried > Baking. Conclusion: steamed processing for water pack polysaccharide retention rate is high, is the water pack of preferred processing method; Boiled, grilled, Fried method should choose low heating temperature.

Abstract: Cassava dregs contain nearly 38.41% of starch, which has a similar structure to that of a starch. It was found that the cassava dregs would have the same function as the cationic starch if cationic groups were introduced. In this study, cationic cassava dregs were synthesized with the laboratory methods and characterized by FT-IR. The factors affect the retention and drainage was investigated. The result showed that, at a dosage of 1.0% of the cationic cassava dregs, the retention of fines was higher than 90%, best flocculation efficiency occurred at pH 8.5 when the dosage of cationic cassava dregs was 1.5%. Cationic cassava dregs had good resistance against moderate shear force, less affected by the conductivity, and it also showed a good strength properties.