Papers by Keyword: Centrifugal Force

Abstract: The use of technology in Indonesia has resulted in an increasing demand for electronic and electrical goods, including printed circuit board (PCB) waste. Currently, PCB waste amounts to 20-50 million tons and continues to grow annually. Given that the composition of PCB waste consists of approximately 40% metals such as Ag, Cu, Fe, Au, Sn, and Mn, recycling PCB FR-2 waste can significantly increase its added value. One effective method is employing a concentration technique to recover these metals. This study aims to investigate the impact of particle size and centrifugal force variations on the content and recovery of Cu and Ag metals in PCB FR-2 waste using a Knelson concentrator. The concentration process involved three size variations: -63+100, -100+150, and-150#, along with three centrifugal force values: 60, 90, and 120 G Force. The results indicate that the size variation-100+150# and a centrifugal force value of 90 G Force exhibited effectiveness in recovering Cu and Ag metals, with a minimal mass loss of 3.9%. The Cu and Ag levels reached 67.49% and 0.18%, respectively, with recovery rates of 53.22% and 39.96%.

Abstract: Condensed Tannin (CT) are secondary metabolites of the plant that synthesized along the phenylpropanoid pathway. It is known to suppress CH₄emission in the rumen through protozoal defaunation as well as direct effects on methanogen bacteria. Recent studies have been reported to have anthelmintics activity to overcome gastrointestinal nematodes, appertain to theHaemonchus contortus. To obtain merits of CT, it can be applied in flour or infusion form. Infusion considered as a convenient alternative of CT application. Evaluation method to produce optimum levels of CT needs to be done for the merits of CT obtained optimally. This study aimed to evaluate the effect of leaf maturity, maceration time, and centrifuge force on CT levels produced in infusion leaf as a feed additive. Mature and immature leaves selected from Morindacitrifolia(CF), Muntingiacalabura(CA), Azadirachta indica(AZ), Hibiscus rosa sinensis (RS) and Hibiscus tiliaceus (HT).The results of this research showed that leaf age had a significant effect on CT, except on AZ and RS. Normally, CT content of immature leaf is higher than the mature leaf. CA has highest levels of CT, can be predicted because of lots of glandular trichomes in their mature leaves as a place to store secondary metabolite compounds. Optimum levels of CT from maceration occurring at 2h of immersion except on HTthat requiring 4h of immersion. Meanwhile, 372 g is the most effective centrifuge force in producing optimum CT, except in CA which requires 2.318 g. Based on this study, it can be concluded that leaf age, maceration time, and centrifuge force have a significant influence in producing an infusion with maximum CTat each stage of extraction. It is important for infusion production to contain CT in optimal amounts. This research is expected to be the first step in providing multifunctional feed additive for livestock.

Abstract: Viability of further research of variatropy is justified, as well as its extended use with the purpose of increasing quality of ferroconcrete building constructions. Raw components and equipment used for manufacturing of centrifuged products and variatropic objects are described. Laboratory centrifuge equipped with a direct current engine and thyristor units has been developed and used. Method of applying pressure to a unit mass during centrifuging has been studied. It has been identified that in order for mix particles rising to their most superior position to stick to the mold walls, it is necessary that gravitational force of mg particle and centrifugal force are equal. Effect of hydrodynamic pressure on particles constituting concrete mix has been studied using several formulas and provisions. It has been revealed that centrifugal molding may be used to seal low-viscosity plastic mixes; however, its use causes disintegration of concrete mix. In order to slow down this process, it is necessary to increase viscosity of the entire system and restrict the upper limit of aggregate fineness.

Abstract: Modeling and simulation of mechanical structures in development phase are fundamental to optimize and improve the stability and reliability of the final product as well as to reduce the cost of prototyping and testing. Wind turbines are subject to critical loading to the centrifugal force due to wind speed and gravitational force. The present study discusses three-dimensional numerical simulations of combined Darrieus-Savonius wind turbine D-SWT for applications in urban and isolated areas for lighting, pumping water, etc. The Darrieus turbine is used to produce wind power and the Savonius rotor to start the system. Finite Element Analysis (FEA) using SolidWorks 2015 is employed to generate the geometry of the structure and SolidWorks Simulation to investigate the stability and reliability static on the structure of the D-WST built by two types of material of the blade Galvanized Steel (GS) and Aluminum alloys 1060-H18 (ALU). Mechanical parameter of the structure are calculated for critical loading conditions, including the gravity and wind pressure loading due to the wind speed of 23m/s. Simulations results indicate no structural failure is predicted for all components of the D-SWT for both materials used according to Von Mises criterion stresses and the factors of safety of the most fragile material are greater than (the unity) 1. The maximum displacements found (3.84 & 6.81mm), occurred at the tip blades (free ends levels). These displacements are accepted relatively to the structure size.

Abstract: A pulsed diaphragm piezoelectric pump using centrifugal force is introduced in this paper. It utilizes centrifugal force in the swing motion of a vibrating tube as the driving force, and to input and output liquid continuously at first bending resonant frequency. The piezoelectric pump based on this principle is expected to effectively coordinate the high frequency characteristics of piezoelectric materials and low frequency characteristics of check valves. Resonant frequency of the pump is studied. A prototype pump was fabricated and tested. Experimental results show that the pump can hold and discharge very precise volume of liquid in every pulse, and can pump tap water at a flow rate of 6.12ml/min under a backpressure of 0.3kPa.

Abstract: A stream turbine bowed and twisted blade has been taken as an example for complex parts. Firstly, a simplified computing method for the blade with centrifugal effect is put forward. Then the finite element model of complex parts with centrifugal effect is established. Simulation results show that errors between calculation and simulation results are less than 15%, the simplified computing method has good application value. In addition, the impacts of centrifugal and heat on blade radial deformation are discussed by thermal structural coupling analysis. Numerical simulation results show that heat is the major factor that affects blade radial deformation.

Abstract: The idea of inertial propulsion using rotating parts is always attractive, but great controversy also exists. Some researchers even completely negate this idea in principle, they think it would never be possible to create directional movement by the inertial force. Theory and experimental results show that, in certain conditions, directional movement can be realized by the internal inertia force of the device. In this paper, the influence of the friction condition between the propulsion devices which using rotating eccentric mass to generate inertia force and the external supporting surface on the effect of propulsion has been analyzed. The results show that, when there is friction between the device and the supporting surface, the rotary of eccentric mass in the device will allow the device to produce motion in a given direction; if the parameters of propulsion device (eccentric mass and eccentricity) and the rotary speed of the eccentric mass are given, the friction condition between the device and the support surface will affect the characteristics of directional motion.

Abstract: This paper established a general mathematical modeling method based on stress analysis of the angular contact ball bearing under high rotation speed. The influence of the centrifugal force and gyroscopic moment generated in the rotation process is taken into account in this mathematical model. This paper conducted in-depth research for these aspects: the stiffness characteristics of angular contact ball bearings under different load conditions and different rotational speed, internal contact deformation and the change of bearing parameters.

Abstract: For ultra-high-speed grinding, the deformation of grinding wheel has a greater impact on the machining accuracy. Finite element method was used to study the radial deformation of the CBN grinding wheel considering centrifugal force and grinding heat. The study shows that the effects of centrifugal force and grinding heat are same magnitude, and the proportion changes with the change of grinding speed and grinding force. By finite element analysis, it is possible to solve the grinding wheel the radial deformation and grinding temperature under different grinding speed and grinding force, and it also provides theoretical support for predicting the machining accuracy, compensating precision and avoiding grinding burn.

Abstract: An optical real-time pneumatic-and-centrifugal controlled microfluidic detection system for dynamic information acquisition is developed based on the quasi-stationary imaging technique. The programmable airflow applied on the centrifugal microstructures for improving efficiency in samples separation. The dynamic characteristic of a loaded disc is stable with vibrating under 0.3 mm at a speed of 1000 rpm by applying 3 bar-induced pneumatic forces on a 12 cm-diameter disc. A conversion model for converting RGB images into CIE L^*a^*b^* color space have been used to enhance the inspection images. A linear relationship between threshold frequency and sample density is 167 rpm/g/cm³. The pressures between 0.1 and 0.5 bars are applied to bias microflow from 15° to 80°. The conduction angles between 30° and 90° have better pneumatic control. The control efficiency observed up to 89% and the largest microflow biased angle reached 80°. The pneumatic force dominates microfluidic behaviors when the force is greater than 10 times the centrifugal force. A sequential of triple-reservoir tests has been verified by analyzing enhanced optical images in separation using arranged acid-base indicators for pH reactions.