scholarly journals Experimental Investigation into Limit Void Ratio Characteristics of Calcareous Sands considering Various Factors

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Baojian Li ◽  
Gang Lei ◽  
Panpan Guo ◽  
Gaoyun Zhou ◽  
Zhe Wang ◽  
...  
Keyword(s):  
Relative Density ◽  
Void Ratio ◽  
Rotation Speed ◽  
Test Methods ◽  
Dry Density ◽  
Fine Content ◽  
Important Index ◽  
Measuring Cylinder ◽  
Calcareous Sands ◽  
The Relationship

Relative density is an important index affecting the mechanical behaviors of calcareous sands. The dense sands present softening strength, whereas the loose sands exhibit hardening strength. Furthermore, the relative density is determined based on the maximum and minimum void ratios obtained by using the maximum and minimum dry density test. In this study, a series of tests were carried out on various mixed graded sands to explore their material properties and the relationship between the limit void ratio, considering the effects of test methods, equipment, and fine content. It is shown that a more accurate maximum void ratio can be attained by using the 1000 mL measuring cylinder with low rotation speed. In addition, in order to avoid particle breakage of calcareous sands, it is suggested that the minimum void ratio should be obtained with the 1000 mL compaction cylinder combining vibration with hit. The results also show that a linear relationship exists among the limit void ratio of various mixed graded sands. Besides, the void ratio is significantly affected by the fine content. 40% is the critical fine content corresponding to the lowest value of the limit void ratio.

scholarly journals Experimental Analysis on Permeability Characteristics of Iron Tailings

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Deqing Gan ◽  
Xi Yang ◽  
Yunpeng Zhang
Keyword(s):  
Particle Size ◽  
Permeability Coefficient ◽  
Void Ratio ◽  
Average Particle Size ◽  
Average Particle ◽  
Fine Content ◽  
Permeability Characteristics ◽  
Permeability Coefficients ◽  
Effective Particle ◽  
The Relationship

The permeability characteristics of iron tailings are one of the important factors affecting the stability of the tailings dam. The permeability properties of undisturbed iron tailings and disturbed iron tailings were analyzed from various aspects such as FC value, gradation, particle size, specific surface area, and interparticle void ratio with water head test in laboratory. The results show that the permeability coefficients of undisturbed iron tailings and disturbed iron tailings are affected by the fine particles content (FC). The threshold of fine content is about 40%. The traditional formulas for calculating the permeability coefficient are applied. But the results are inaccurate. The relationship between permeability coefficient of the iron tailings (undisturbed iron tailings and disturbed iron tailings) and the nonuniform coefficient (Cu), the curvature coefficient (Cc), the average particle size, the weighted average particle size, the specific surface area, and the skeleton void ratio (es) is nonlinear. It is difficult to characterize the change of permeability coefficient when the fine content is large. However, the relationship between permeability coefficient of the iron tailings (undisturbed iron tailings and disturbed iron tailings) and the effective particle size and silt particles void ratio (ef) is linear. A formula was developed for the determination of permeability coefficient of iron tailings by analyzing the effective particle size and silt particles void ratio. And it is more accurate. The permeability coefficients of disturbed samples are slightly larger than the permeability coefficients of undisturbed sample. This is due to the destruction of the sedimentary structure of the tailings and increasing e. Maybe the R in the new formula is affected by the structure of iron tailings. This requires further research.

Study on the Permeability Characteristics of Coarse-Grained Soil and its Permeability Rule

2014 ◽  
Vol 904 ◽  
pp. 383-388
Author(s):  
Wen Bo Li
Keyword(s):  
Permeability Coefficient ◽  
Void Ratio ◽  
Coarse Grained ◽  
Dry Density ◽  
Fines Content ◽  
Permeability Characteristics ◽  
The Relationship ◽  
Coarse Grained Soil

The permeability of coarse-grained soil is influenced by many factors. The results of permeability tests in different conditions indicate the effects of coarse-grained soil dry density of , fines content P5,void ratio e and nonuniform coefficient Cu to the permeability coefficient. Analyzing the relationship between coarse-grained soil dry density , fines content P5, void ratio e, nonuniform coefficient Cu and permeability coefficient, thus there is a relational expression between coarse-grained soil dry density of soil , fines content P5, void ratio e, nonuniform coefficient Cu and permeability coefficient.

An evaluation of ECT sample height for small flute board grades and Box Manufacturer’s Certification compliance

TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 24-28
Author(s):  
CORY JAY WILSON ◽  
BENJAMIN FRANK
Keyword(s):  
Compressive Strength ◽  
Compressive Load ◽  
Test Sample ◽  
Test Methods ◽  
Test Method ◽  
Initial Development ◽  
Sample Height ◽  
Relationship Of ◽  
The Relationship ◽  
Corrugated Fiberboard

TAPPI test T811 is the specified method to ascertain ECT relative to box manufacturer’s certification compliance of corrugated fiberboard under Rule 41/ Alternate Item 222. T811 test sample heights were derived from typical board constructions at the time of the test method’s initial development. New, smaller flute sizes have since been developed, and the use of lighter weight boards has become more common. The T811 test method includes sample specifications for typical A-flute, B-flute, and C-flute singlewall (and doublewall and triplewall) structures, but not for newer thinner E-flute or F-flute structures. This research explores the relationship of ECT sample height to measured compressive load, in an effort to determine valid E-flute and F-flute ECT sample heights for use with the T811 method. Through this process, it identifies challenges present in our use of current ECT test methods as a measure of intrinsic compressive strength for smaller flute structures. The data does not support the use of TAPPI T 811 for ECT measurement for E and F flute structures, and demonstrates inconsistencies with current height specifi-cations for some lightweight B flute.

Pulse-Width Modulated Amplifier for DC Servo System and Its Matlab Simulation

2015 ◽  
Vol 9 (1) ◽  
pp. 625-631
Author(s):  
Ma Xiaocheng ◽  
Zhang Haotian ◽  
Cheng Yiqing ◽  
Zhu Lina ◽  
Wu Dan
Keyword(s):  
Mathematical Model ◽  
Transfer Function ◽  
Input Signal ◽  
Pulse Width ◽  
Rotation Speed ◽  
Servo Motor ◽  
Matlab Simulation ◽  
Pulse Width Modulated ◽  
Signal Changes ◽  
The Relationship

This paper introduces a mathematical model for Pulse-Width Modulated Amplifier for DC Servo Motor. The relationship between pulse-width modulated (PWM) signal and reference rotation speed is specified, and a general model of motor represented by transfer function is also put forward. When the input signal changes, the rotation speed of the servo motor will change accordingly. By changing zeros and poles, transient performance of this system is discussed in detail, and optimal ranges of the parameters is recommended at the end of discussion.

EFFECT OF SPACING AND CLUMPING OF CORN PLANTS ON DENSITY OF CORN-ROOTWORM LARVAE (COLEOPTERA: CHRYSOMELIDAE) PER ROOT SYSTEM

1985 ◽  
Vol 117 (2) ◽  
pp. 139-142 ◽  
Author(s):  
Olga Piedrahita ◽  
C. R. Ellis ◽  
O. B. Allen
Keyword(s):  
Relative Density ◽  
Root System ◽  
Corn Rootworm ◽  
Plant Spacing ◽  
Corn Rootworms ◽  
Corn Plants ◽  
The Relationship ◽  
Field Plots

AbstractThe relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.

scholarly journals FEM modeling on the compaction of Fe and Al composite powders

2015 ◽  
Vol 51 (2) ◽  
pp. 163-171 ◽  
Author(s):  
P. Han ◽  
X.Z. An ◽  
Y.X. Zhang ◽  
Z.S. Zou
Keyword(s):  
Relative Density ◽  
Flow Behavior ◽  
Compaction Pressure ◽  
Pressure Effects ◽  
Von Mises Stress ◽  
Composite Powders ◽  
Al Content ◽  
Ejection Force ◽  
Al Composite ◽  
The Relationship

The compaction process of Fe and Al composite powders subjected to single action die compaction was numerically modeled by FEM method. The relationship between the overall relative density and compaction pressure of the compacts with various Al contents was firstly identified, and the influences of Al content on the local relative density, stress, and their distributions were studied. Then the compaction pressure effects on the above properties with fixed Al content were discussed. Furthermore, detailed flow behaviors of the composite powders during compaction and the relationship between the compaction pressure and the ejection force/spring back of the compact were analyzed. The results show that: (1) With each compaction pressure, higher relative density can be realized with the increase of Al content and the relative density distribution tends to be uniform; (2) When the Al content is fixed, higher compaction pressure can lead to composite compact with higher relative density, and the equivalent Von Mises stress in the central part of the compact increases gradually; (3) Convective flow occurs at the top and bottom parts of the compact close to the die wall, each indicates a different flow behavior; (4) The larger the compaction pressure for each case, the higher the residual elasticity, and the larger the ejection force needed.

scholarly journals Career Satisfaction Based on Trust and Proactive Personality

2020 ◽  
Vol 9 (1) ◽  
pp. 35-45
Author(s):  
Iwan Sunardi ◽  
Vini Wiratno Putri
Keyword(s):  
Career Satisfaction ◽  
Analytical Data ◽  
Sampling Technique ◽  
Test Methods ◽  
Validity And Reliability ◽  
Career Needs ◽  
Relationship Of ◽  
The Relationship ◽  
The City

The purpose of this study was to examine the effect of the trust of co-workers and proactive personalities on career satisfaction by exchanging leader-members as mediation on employees of bus assembly companies in the city of Semarang. Career satisfaction is the phase in which employees’ long-term career needs are aligned with what they get while working. Employees will always look for opportunities and trust in the organization and people who will help them in achieving career satisfaction. The sampling method uses a purposive sampling technique in the category of staff and foreman employees who have worked for more than five years with a sample of 160 employees. The analytical data in this study uses descriptive statistical test methods, instinctual tests include validity and reliability, and hypothesis testing. The tool used to test in this study uses SmartPLS 3.0. The results of this study, colleague trust cannot directly influence career satisfaction. However, it can be mediated by the exchange of leader members and produce significant influence. For further researchers, they can re-examine the relationship of coworkers’ trust with career satisfaction. And can expand the object of research or respondents under study.

scholarly journals Study on Sludge and Dissolved Oxygen Distribution in a Full-Scale A2/O Oxidation Ditch

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2776
Author(s):  
Chengyi Li ◽  
Zhao Han ◽  
Yuquan Zhang ◽  
Yuan Zheng ◽  
Hepeng Zhang ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Flow Model ◽  
Rotation Speed ◽  
Full Scale ◽  
Oxidation Ditch ◽  
Bed Height ◽  
Consumption Rates ◽  
The Relationship ◽  
Oxygenation Rate ◽  
Biological Selection

The distribution of velocity, sludge, and dissolved oxygen in a full-scale anaerobic-anoxic-oxic (A2/O) oxidation ditch was numerically simulated under three rotation speed scenarios. The viscosity and settling rate of activated sludge were defined through a user-defined function (UDF), and the sludge phase was calculated using the mixture multiphase flow model. Dissolved oxygen (DO) was set as a user-defined source (UDS) and its generation and consumption rates were defined with UDFs. The relationship between velocity and sludge concentration was found to be contradictory, with dead zones leading to large sludge concentrations at the bottom of the oxidation ditch (OD), but not at the middle-curved wall of the anoxic pool. The flow rate of the reflux slot and aerator oxygenation rate were checked and correlated with DO concentrations in the anaerobic pool. The majority of the large sludge concentrations were concentrated in the biological selection pool and these remained constant with bed height. With reduced propeller and agitator rotation speed, the sludge concentrations reduced in the biological selection pool, but increased in the anaerobic and anoxic pools.

Model of Product Warranty Network and its Robustness

2012 ◽  
Vol 482-484 ◽  
pp. 2165-2169
Author(s):  
Jian Yu ◽  
Zhen Zhang
Keyword(s):  
Shortest Path ◽  
Evolutionary Model ◽  
Important Index ◽  
Product Warranty ◽  
The Relationship ◽  
Random Failures

Robustness is an important index to assess the performance of product warranty network, and it’s helpful for managing the relationship between the manufacturers and the suppliers to analyze it. The paper establishes product warranty network’s evolutionary model according to its characteristics, and chooses the average shortest path as the measures of robustness to analyze the robustness of model of product warranty network under the random attack and the selective attack. The conclusions show that the product warranty network have strong tolerance against random failures yet are fragile under selective attacks.

Sign in / Sign up

Export Citation Format

Share Document