scholarly journals Study on the Dynamic Response of Gravel Soil Low Embankment under a Long-Time Dynamic Loading Based on Model Test

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Dapeng Liu ◽  
Jing Wang ◽  
Feng Du

The low embankment is an important technique for road development in subgrade engineering due to its small fill height and applicability to the natural landscape in the oasis desert area of Xinjiang, China. A reasonable development of the gravel soil low embankment design requires the study of its dynamic response under a long-time dynamic loading. In the paper, a 1 : 1 full-scale low embankment model was established and tests of 100000 loading cycles with 50 kN peak value were carried out, taking into account three kinds of foundation moisture contents: 18%, 23%, and 28%. The test results show that the dynamic stress in the gravel soil low embankment attenuates nonlinearly with the increase in depth. The dynamic stress at each depth is the smallest for the water content value of 28% in the foundation. The stress attenuation rate is inversely proportional to the loading cycles and directly proportional to the water content of the foundation. The dynamic stress and dynamic strain in the gravel soil low embankment show cumulative effects with an increase of the loading cycles. The rate of stress and strain accumulation is faster for low loading cycles. The strain accumulation effect of each structural layer in the foundation is the largest for the water content value of 28%. The strain accumulation rate at the top layer of the foundation reaches 2.648. Based on the model test results, the dynamic stress calculation model for the gravel soil low embankment under dynamic loading is proposed. The calculation model was experimentally verified. The research results are important for the application of gravel soil low embankment in the oasis desert area of Xinjiang, China.

2022 ◽  
Vol 905 ◽  
pp. 314-319
Author(s):  
Lin Liu ◽  
Jing Chang Wang

In order to study the influence of water content and hydration degree on the thermal conductivity of concrete, based on the steady-state plate method, the influence of water content, temperature, hydration degree and other factors on the thermal conductivity of early concrete was studied, and the calculation model of thermal conductivity of early concrete was established according to the test results and influence rules. The results show that there is a linear relationship between the thermal conductivity and water content at 28d, the higher the hydration degree is, the lower the thermal conductivity of concrete is; the difference between the measured value and the calculated model value is small, and the calculation formula can meet the requirements of engineering calculation.


2020 ◽  
Vol 3 (2) ◽  
pp. 103-113
Author(s):  
Rachmad Ikhsan ◽  
Effendi Effendi

Roasting coffee manually is widely applied by coffee producers. This process takes a very long time and is less efficient in terms of productivity for industry standards. This machine  is equipped with a thermocouple sensor as a temperature sensor that will measure the temperature in the roasting cylinder, then equipped with a timer as a reminder of roasting time that ranges from 15 minutes at a temperature of 200 degrees Celsius, this machine  is also equipped with android as a timer controller on the coffee roaster machine. This machine is also equipped with a microcontroller and Bluetooth as a media transmitter and data receiver. From the test results obtained data that Bluetooth can be used for data communication between the microcontroller and Android with a distance of 30 meters in the room, and 12 meters outside the room. If it exceeds that distance, then Bluetooth will not respond back


2020 ◽  
Vol 8 (2) ◽  
pp. 134-142
Author(s):  
Salma Shafrina Aulia ◽  
Budi Setiawan ◽  
Tiurma Sinaga ◽  
Ahmad Sulaeman

Background: Instant pumpkin cream soup enriched with tempeh had fulfilled 10% Recommended Dietary Allowances (RDA) for elderly so that it can be used as an easy-to-serve snack, but decreasing quality of instant cream soup will be happened if the instant cream soup was stored for a long time. Objectives: This study aimed to analyze quality of water content, water activity and lipid oxidation in instant pumpkin cream soup during storage and estimated the shelf life of pumpkin cream soup enriched with tempeh.Method:  Quality storage was analyzed using of water content, water activity (aw) and lipid oxidation. Estimation of shelf life was analyzed using Arrhenius Accelerated Shelf Life Testing (ASLT) model.Results: The results showed that the water content, aw levels and lipid oxidation of instant pumpkin cream soup increased during the storage period. The critical parameter used in this study was lipid oxidation. Instant cream soup without the addition of tempeh can last 447 days  while the cream soup with the addition of tempeh has a shelf life of 433 days.Conclusion: Quality of instant pumpkin cream soup decreased during the storage period and it would be expired over a year.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.


1954 ◽  
Vol 21 (3) ◽  
pp. 225-235
Author(s):  
A. M. Wahl ◽  
G. O. Sankey ◽  
M. J. Manjoine ◽  
E. Shoemaker

Abstract A theoretical and experimental program involving methods of calculating creep in rotating disks at elevated temperatures is described. This program consisted primarily of the following: (a) Obtaining forged disks from the same ingot of 12 per cent chrome steel, all disks being forged and heat-treated in the same manner; (b) making spin tests at 1000 F on three of these disks for periods up to about 1000 hr; ( ) making long-time tension-creep tests at 1000 F on many specimens cut out circumferentially from several of the other disks at stresses approximating those of the spin tests; (d) investigating theoretical methods of calculation of creep deformation in such disks; and (e) comparison of spin-test results with those calculated theoretically using average tension-creep data. It was found that available methods of calculating rotating disks based on the Mises criterion gave creep deformations too low compared to the test values, i.e., on the unsafe side for design. Considerably better agreement between test and theoretical results is obtained if the latter is based on the maximum-shear theory. Some discussion is given of the reasons for the better agreement obtained using the latter theory; these are believed to be related in part to the anisotropy of the forged material tested. Further tests on other materials are necessary before general conclusions can be drawn; however, in the absence of test data it is suggested that a conservative course in design for such disks is to apply the maximum-shear theory.


2019 ◽  
Vol 2 (1) ◽  
pp. 8-14
Author(s):  
Beauty Novianty ◽  
Ella Amalia ◽  
Ziske Maritska ◽  
Yuwono Yuwono ◽  
Lusia Hayati

Background: Over the past decade, numbers of Carbapenemase Producing-Carbapenem Resistant Enterobacteriaceae (CP-CRE) has been increasing worldwide and it has been becoming a threat because of its resistance against carbapenem which is considered as the “last resort” antibiotic. Therapy options for its infection are still limited. Aminoglycoside serves as one of the most commonly used antibiotics, but the resistance against it has already been presented for a long time. Aminoglycoside Modifying Enzyme (AME) is the most important resistance mechanism against aminoglycoside. AAC(6’)-Ib enzyme is one of the most common AME produced by the gram-negative bacteria.Objectives: This study wished to identify the gene of this enzyme among CRE isolated from infected Indonesian patients in Dr. Mohammad Hoesin Hospital Palembang.Methods: Twenty-eight isolates collected from CRE-infected patients identified by Vitek 2 Compact (bioMerieux, USA) in dr. Mohammad Hoesin Hospital Palembang during September—November 2017. AAC(6’)-Ib gene was identified using PCR method, then visualize by electrophoresis. The result is then analyzed by comparing it with a susceptibility test.  Results: Out of 28 samples, AAC(6’)-Ib is identified in 22 (78.57%) samples. Samples with AAC(6’)-Ib showed to be less resistant to various antibiotics, significantly to amikacin (p=0.023).Conclusion: AAC(6’)-Ib gene is found in most of samples implying its frequent occurrence in Indonesian patients.


2020 ◽  
Vol 25 (1) ◽  
pp. 52
Author(s):  
Alston Millan

Nutmeg oleoresin microcapsule is the solid, liquid, and gas coating technology of the nutmeg fruit.  The purpose of this study was to know how mace nutmeg oleoresin microcapsules could preserve the broiler chicken meat at room temperature during 4 days of observation. The experimental design used was a Completely Randomized Design (CRD) consisting of 5 treatments with mace concentration of nutmeg microcapsules oleoresin (0, 50, 100, 150, and 200) ppm. The variables observed were water content, pH value, total microbes, and organoleptic properties (color, aroma, and texture). The results showed that mace nutmeg oleoresin microcapsules did not affect (p> 0.05)  water content and sensory properties of broiler chicken meat, but had a significant effect (p <0.05) on the pH value and total microbe at the same day of room temperature storage. Panel organoleptic test results on the level of preference for meat color, aroma, and texture of chicken meat were in the range score of 3 (somewhat like) to 4 (somewhat dislike). The treatments of nutmeg oleoresin did not affect (p> 0.05) on color, the aroma, and the texture of broiler chicken meat. This research shows that marinating using oleoresin microcapsules has not been effective as a preservative to broiler chicken meat at room temperature. Keywords: chicken meat, mace nutmeg oleoresin microcapsules


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