Research on Application of Multi-Channel Selector in Centrifugal Model Test of Anchoring Slope by Frame Beam

An anchoring frame beam is a very common form of support for reinforced slopes, especially in alpine regions. Centrifugal tests have proved to be an intuitive and effective means of investigating the mechanism of action of frame beams. However, the data acquisition system of the geotechnical centrifuge in service has the problem of a small number of acquisition channels. A multi-channel selector based on the existing acquisition system was proposed, designed, processed, and manufactured, and it was debugged, tested, and applied in a no-load centrifugal test, static pressure model test, and centrifugal model test. The results show that the acquisition mode of the multi-channel selector connected with a maximum of 288 sensors has been changed from “one-to-one” to “one-to-many”. Its influence on various sensor signals is negligible. The multi-channel selector can work normally, which communicates and feeds back with the remote controller in the 1–120 g no-load centrifugal test. In the static load model test, 162 sensor signals were well collected through it. And only 51 channels were used to effectively obtain the signals of 187 sensors in a 70 g centrifugal model test of an anchoring slope with a frame beam. The multi-channel selector can be successfully applied in different use environments, saving time and reducing the cost of obtaining a single set of data.

Research on the Method of Solving Kinematics Parameters of Three-axis Dynamic Centrifuge

With the development of aerospace technology, the maneuverability of various types of aircraft continues to improve, and these aircraft experience an overload environment with high acceleration and high acceleration rate. Due to the special influence brought by the high acceleration rate, the dynamic centrifugal test technology, which is different from the traditional steady-state centrifugal test technology, came into being. The steady-state centrifuge has only one rotor, while the dynamic centrifuge has multiple rotors; so, the relationship between the acceleration of the control point and the motion parameters of the rotors is more complicated. Therefore, a key issue of the dynamic centrifugal test technology is the inverse kinematics of the dynamic centrifuge, which is to calculate the kinematic parameters of the dynamic centrifuge according to the expected acceleration environment that needs to be simulated on the centrifuge. After the kinematic parameters is calculated, the control target of each rotor of the dynamic centrifuge could be known, then the expected acceleration environment could be produced. In this paper, 1) on the basis of the predecessors, the equation for solving the angular velocity of the main arm of the centrifuge is improved; 2) and then a time step adaptive method is proposed, which takes into account the calculation accuracy and efficiency. As a result, an inverse kinematics algorithm that is more accurate and adaptable to various acceleration history curve is obtained. Finally, the inverse kinematics algorithm in this paper is verified through experiments and numerical simulations.

FORMULASI DAN UJI STABILITAS KRIM ASAM KOJAT DALAM PEMBAWA VESIKEL ETOSOM

Asam kojat diketahui memiliki efektivitas untuk mencerahkan kulit. Tetapi asam kojat bersifat hidrofilik, sehingga sulit berpenetrasi ke dalam kulit oleh karena itu diperlukan sistem penghantaran etosom untuk meningkatkan penetrasi asam kojat dalam bentuk sediaan krim untuk memudahkan pengaplikasiannya di kulit. Penelitian ini bertujuan untuk membuat formula krim etosom asam kojat menggunakan kombinasi emulgator tween 80 dan span 80 dalam berbagai konsentrasi, serta menguji kestabilan fisik sediaan krim. Uji stabilitas krim dilakukan menggunakan metode cycling test dan centrifugal test. Metode cycling test meliputi pengamatan organoleptik, tipe krim, pH, viskositas, ukuran globul, daya sebar dan homogenitas krim, sedangkan metode centrifugal test dilakukan menggunakan alat sentrifugasi untuk melihat terjadinya pemisahan fase pada krim. Hasil penelitian menunjukkan adanya perbedaan nilai organoleptik, pH, viskositas, ukuran globul dan daya sebar namun tidak terjadi pemisahan fase setelah uji centrifugal test. Sehingga diperoleh krim yang paling stabil yaitu pada formula krim dengan konsentrasi emulgator 3%, memiliki nilai organoleptik yang baik, tipe krim m/a, pH 5,24, viskositas 22.200 cPs, ukuran globul berkisar 0,1-0,3 µm, daya sebar 4,1 cm2, krim yang homogen, dan tidak terjadi pemisahan fase setelah uji sentrifugasi. Hasil penelitian ini menunjukkan etosom asam kojat dapat diformulasi menjadi sediaan krim yang stabil

Modeling of Loess Soaking Induced Impacts on a Metro Tunnel Using a Water Soaking System in Centrifuge

The collapsibility is one of the key properties for loess. Harmful impacts on the metro tunnels could be obviously subjected to the soaking collapsibility in collapsible loess. However, loess soaking cannot be effectively modeled by the existing centrifugal test equipment (CTE) due to its inherent limitations. In the present paper, a water soaking system (WSS) was improved based on the existing CTE for simulating various loess soaking conditions. The WSS was made of a water storage subsystem and a water distribution subsystem. Some tests were conducted to show the capability of the improved WSS in centrifugal model tests firstly, then it was used to carry out centrifugal model tests on a metro tunnel under full-range and half-range foundation soaking conditions with different soaking depths. The impacts of various soaking conditions on the mechanical properties of the metro tunnel were discussed in detail.

Design and Analysis of the Elastic-Beam Delaying Mechanism in a Micro-Electro-Mechanical Systems Device

The delaying mechanism is an important part of micro-electro-mechanical systems (MEMS) devices. However, very few mechanical delaying mechanisms are available. In this paper, an elastic-beam delaying mechanism has been proposed innovatively through establishing a three-dimensional model of an elastic-beam delay mechanism, establishing the force and the parameters of an elastic-beam delay mechanism, deriving the mathematical model according to the rigid dynamic mechanics theory, establishing the finite element model by using Ls-dyna solver of the Ansys software, and carrying out the centrifugal test. Simulation and test results match theoretical results quite well. It is believed that the elastic-beam delaying mechanism is quite effective and useful to slow the speed of the movable part in MEMS devices.

Equivalence relationship between a three-axis centrifugal test load and flight load

For aircraft flying with high accelerations and high acceleration change rates in three-dimensional space, load simulation tests are usually carried out in a three-axis centrifuge with three degrees of freedom. A triaxial centrifugal test that simulates the actual flight environment must reflect the real effect of the flight load on the structure. An acceleration analysis model of a three-axis centrifuge in body coordinates is established to meet this requirement. The spatial distribution of the acceleration and the effects of kinematic parameters on acceleration are analyzed. Using the acceleration analysis model, the displacement equivalence and strain energy equivalence relations of a beam in a centrifugal environment and actual flight environment are studied. Moreover, equivalence relationships meeting requirements are proposed and validated for a specific example. The distribution of the acceleration and the equivalence relations of the two environments are the basis for the ground simulation of flight loads.

STABILITY TESTING OF AZELAIC ACID CREAM BASED ETHOSOME

Objective: Azelaic acid as an antibacterial to Propionibacterium acnes bacteria in recent years began to develop as an anti-acne using lipid bilayer vesicles to increase the penetration of azelaic acid to reach sebaceous tissue which is located in the dermis of skin where the growth of bacteria P. acnes. The development of azelaic acid in lipid bilayer vesicles is also due to the absorption of azelaic acid from cream preparations by only 4%. Azelaic acid gel based ethosomes also known give a larger zone of inhibition than azelaic acid creams and gels in the market. Methods: Preparation stability test of azelaic acid cream based ethosome was chemical and physical stability. The observed physics stability was organoleptic changes, homogeneity, pH, viscosity, cycling test, and mechanical test (centrifugal test). While chemical stability was performed to know the concentration of azelaic acid in cream to be periodically. Stability test was conducted for 12 weeks and observation every 2 weeks. Result: Physics stability test of that preparations was odorless, white, no change of phase, homogeneous, viscosity, and flow properties constant. While chemical stability test with the determination for 12 weeks to decreased content. However, these content is still included in the range of accuracy (90–110%). Conclusion: Azelaic acid of ethosome cream was physically and chemically stable.

Ratio of Seaweed Porridge Eucheuma cottonii and Sargassum sp. as a Sunscreen Cream Formula

The use of sunscreen is highly recommended to protect the health of the skin from ultraviolet radiation.<br />The aim of this study was to get the best ratio sunscreen preparation of porridge E. cottonii and Sargassum<br />sp. through the total test microbes, antioxidants and SPF value, get a stable cream preparations physically<br />through sensory test, pH, consistency, Cycling test and centrifugal test. The main materials used were E.<br />cottonii, Sargassum sp. and raw materials stocks cream. This study used a completely randomized design<br />(CRD), which consisted of four treatments with two replications.The results showed that the best ratio of<br />sunscreen cream was cream with the addition of E. cottonii and Sargassum (1:1). The result obtained was<br />the absence of microbs at creams and porridge E. cottonii and Sargassum sp. The antioxidant activity of E.<br />cottonii porridge 127.23 ± 2.77μg/mL, Sargassum sp. 119.66 ± 0.25 μg/mL, and cream 83.4 ± 0.03 μg/mL.<br />Cream SPF value was 7.03 ± 0.01. Consumer acceptance of the products through sensory test ranged from<br />normal to like. Sunscreen creams had good physical stability and the cream has a shelf life preparation one<br />year.<br /><br />

Ratio of Seaweed Porridge Eucheuma cottonii and Sargassum sp. as a Sunscreen Cream Formula

Abstract<br />The use of sunscreen is highly recommended to protect the health of the skin from ultraviolet radiation.<br />The aim of this study were to get the best ratio sunscreen preparation of porridge E. cottonii and Sargassum<br />sp. through the total test microbes, antioxidants and SPF value, get a stable cream preparations physically<br />through sensory test, pH, consistency, Cycling test and centrifugal test. The main materials used were E.<br />cottonii, Sargassum sp. and raw materials stocks cream. This study used a completely randomized design<br />(CRD), which consisted of four treatments with two replications.The results showed that the best ratio of<br />sunscreen cream was cream with the addition of E. cottonii and Sargassum (1:1). The result obtained was<br />the absence of microbs at creams and porridge E. cottonii and Sargassum sp. The antioxidant activity of E.<br />cottonii porridge 127.23 ± 2.77μg/mL, Sargassum sp. 119.66 ± 0.25 μg/mL, and cream 83.4 ± 0.03 μg/mL.<br />Cream SPF value was 7.03 ± 0.01. Consumer acceptance of the products through sensory test ranged from<br />normal to like. Sunscreen creams had good physical stability and the cream has a shelf life preparation one<br />year.<br /><br />