A comprehensive study of single-flawed granite hydraulically fracturing with laboratory experiments and flat-jointed bonded particle modeling

2021 ◽  
Vol 140 ◽  
pp. 104440
Author(s):  
Rui Zhang ◽  
Cheng Zhao ◽  
Chengye Yang ◽  
Jinquan Xing ◽  
Chihiro Morita
Keyword(s):  
Laboratory Experiments ◽  
Particle Modeling ◽  
Comprehensive Study

scholarly journals A COMPREHENSIVE STUDY OF THE STABILITY OF LATERAL ROCKS WITH A SUPPLE SUPPORT

World Science ◽  
2020 ◽  
Vol 1 (1(53)) ◽  
pp. 4-17 ◽  
Author(s):  
Iordanov I. V. ◽  
Simonova Yu. I. ◽  
Polozhy A. V. ◽  
Podkopayev Ye. S. ◽  
Skyrda A. Ye. ◽  
...  
Keyword(s):  
Strain State ◽  
Laboratory Experiments ◽  
Flexible Structures ◽  
Crushed Rock ◽  
Beam Model ◽  
Coal Pillars ◽  
The Stability ◽  
Stratified Rock ◽  
Roof Rocks ◽  
Comprehensive Study

A complex of analytical studies of the stability of lateral rocks with a supple support, where the coal seam roof was a beam model, some laboratory experiments on samples made from optical and equivalent materials, as well as some mine experiments were was carried out. As a result of the studies, it was found that the stability of lateral rocks with a supple support of crushed rock depended on the compaction of the backfill array on which the roof rocks were based. It was experimentally proved that with external force, the coefficient of compaction of the backfill array changes according to the hyperbolic dependence, the maximum values of which were determined as a result of compaction of the supple support consisting of heterogeneous fractions of the starting material of a certain bulk density. The change in the stress-strain state of the lateral rocks in the coal array with a roadway depended on the bending stiffness of the stratified rock mass and the parameters of flexible structures used to support the roadway. When supporting the roadways with supple support structures, the convergence of the lateral rocks on the contour of the stoop roadway was observed exponentially until the support was completely compressed, while supporting the roadways with coal pillars, the displacement of the rocks on the contour of the roadway increased having linear dependence due to the destruction of the pillar. The stability of the lateral rocks, which determines the operational state of the excavation roadways, was ensured by the use of supple supports or stowing the mined-out space, taking into account the reasonable granulometric content of crushed rock, which ensured the maximum values of the compaction coefficient of the backfill array when the roof and coal seat got deformed.

Design evaluation of multiroll mills for small-diameter wire rolling

2001 ◽  
Vol 215 (1) ◽  
pp. 77-86
Author(s):  
K Kuroda ◽  
T Kuboki ◽  
Y Imamura ◽  
C Hayashi
Keyword(s):  
Numerical Experiments ◽  
Laboratory Experiments ◽  
Small Diameter ◽  
Wire Diameter ◽  
Experimental Results ◽  
Design Evaluation ◽  
Dimensional Precision ◽  
Roll Mill ◽  
Rolled Wire ◽  
Comprehensive Study

A comprehensive study on the evaluation of mill designs was carried out for three types of multiroll mill for wire rolling by using both prototype mills and numerical experiments. The laboratory experiments were carried out in order to examine both the deformation and loading characteristics of two-, three- and four-roll mills using a set of rolls of the same diameter. As a result, the data allow a direct comparison of the rolling characteristics among the three types of mill, which is not found in previous work. The analytical results showed a good matching with the experimental results, and evaluation was then carried out on the three mills. It has been found that the four-roll mill ensures the highest reduction and the two-roll mill the lowest reduction under the restriction that certain dimensional precision of the rolled wire be maintained. This tendency becomes greater as wire diameter decreases and in practice it is recommended that a four-roll mill equipped with small-diameter rolls be used when rolling small-diameter wire. As regarding the loading characteristics, similar conclusions apply. Finally, domains were determined where four-roll mills show their marked superiority.

scholarly journals Solar irradiances measured using SPN1 radiometers: uncertainties and clues for development

2014 ◽  
Vol 7 (12) ◽  
pp. 4267-4283 ◽  
Author(s):  
J. Badosa ◽  
J. Wood ◽  
P. Blanc ◽  
C. N. Long ◽  
L. Vuilleumier ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Laboratory Experiments ◽  
State Of The Art ◽  
Low Cost ◽  
Operating Costs ◽  
Capital Maintenance ◽  
Sources Of Uncertainty ◽  
Energy Applications ◽  
Fast Development ◽  
Comprehensive Study

Abstract. The fast development of solar radiation and energy applications, such as photovoltaic and solar thermodynamic systems, has increased the need for solar radiation measurement and monitoring, for not only the global but also the diffuse and direct components. End users look for the best compromise between getting close to state-of-the-art measurements and keeping low capital, maintenance and operating costs. Among the existing commercial options, SPN1 is a relatively low cost solar radiometer that estimates global and diffuse solar irradiances from seven thermopile sensors under a shading mask and without moving parts. This work presents a comprehensive study of SPN1 accuracy and sources of uncertainty, drawing on laboratory experiments, numerical modelling and comparison studies between measurements from this sensor and state-of-the art instruments for six diverse sites. Several clues are provided for improving the SPN1 accuracy and agreement with state-of-the art measurements.

scholarly journals Solar irradiances measured using SPN1 radiometers: uncertainties and clues for development

2014 ◽  
Vol 7 (8) ◽  
pp. 8149-8191
Author(s):  
J. Badosa ◽  
J. Wood ◽  
P. Blanc ◽  
C. N. Long ◽  
L. Vuilleumier ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Laboratory Experiments ◽  
State Of The Art ◽  
Low Cost ◽  
Operating Costs ◽  
Capital Maintenance ◽  
Sources Of Uncertainty ◽  
Energy Applications ◽  
Fast Development ◽  
Comprehensive Study

Abstract. The fast development of solar radiation and energy applications, such as photovoltaic and solar thermodynamic systems, has increased the need for solar radiation measurement and monitoring, not only for the global component but also for the diffuse and direct. End users look for the best compromise between getting close to state-of-the-art measurements and keeping low capital, maintenance and operating costs. Among the existing commercial options, SPN1 is a relatively low cost solar radiometer that estimates global and diffuse solar irradiances from seven thermopile sensors under a shading mask and without moving parts. This work presents a comprehensive study of SPN1 accuracy and sources of uncertainty, which results from laboratory experiments, numerical modeling and comparison studies between measurements from this sensor and state-of-the art instruments for six diverse sites. Several clues are provided for improving the SPN1 accuracy and agreement with state-of-the art measurements.

Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Hexachlorobenzene toxicity in the monkey ovary: III. Ultrastructure induced by high (10 mg/kg) dose exposure

1991 ◽  
Vol 49 ◽  
pp. 130-131
Author(s):  
A. Singh ◽  
A. Dykeman ◽  
J. Jarrelf ◽  
D. C. Villeneuve
Keyword(s):  
Present Report ◽  
Reproductive Toxicity ◽  
Control Group ◽  
Primate Model ◽  
Human Follicular Fluid ◽  
Thin Sections ◽  
Cynomolgus Monkeys ◽  
Cacodylate Buffer ◽  
Induction Cycle ◽  
Comprehensive Study

Hexachlorobenzene (HCB), a persistent and mobile organochlorine pesticide, occurs in environment. HCB has been shown to be present in human follicular fluid. An objective of the present report, which is part of a comprehensive study on reproductive toxicity of HCB, was to determine the cytologic effects of the compound on ovarian follicles in a primate model.Materials and Methods. Eight Cynomolgus monkeys were housed under controlled conditions at Animal facility of Health and Welfare, Ottawa. Animals were orally administered gelatin capsules containing HCB mixed with glucose in daily dosages of 0.0 or 10 mg/kg b.w. for 90 days; the former was the control group. On the menstrual period following completion of dosing, the monkeys underwent an induction cycle of superovulation. At necropsy, one-half of an ovary from each animal was diced into ca. 2- to 3-mm cubed specimens that were fixed by immersion in 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.3). Subsequent procedures followed to obtain thin sections that were examined in a Hitachi H-7000 electron microscope have been described earlier.

Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 52-53
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Plastic Strain ◽  
Cell Walls ◽  
Room Temperature ◽  
Mechanical Response ◽  
Biaxial Tension ◽  
Initial Deformation ◽  
Uniaxial Deformation ◽  
Biaxial Deformation ◽  
Stress States ◽  
Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

Microvasculature and structure of hemal lymph nodes in the wall of the rabbit bladder: a vascular corrosion casting and EM study

1995 ◽  
Vol 53 ◽  
pp. 1074-1075
Author(s):  
F.E. Hossler ◽  
M.I. McKamey ◽  
F.C. Monson
Keyword(s):  
Lymph Nodes ◽  
Light Microscopy ◽  
Corrosion Casting ◽  
Fixed Tissue ◽  
Infusion Pressure ◽  
India Ink ◽  
Cacodylate Buffer ◽  
Rabbit Bladder ◽  
Lateral Walls ◽  
Comprehensive Study

A comprehensive study of the microvasculature of the normal rabbit bladder, revealed unusual "capillary glomeruli" along the lateral walls. Here they are characterized as hemal lymph nodes using light microscopy, SEM, TEM, ink injection, and vascular casting.Bladders were perfused via a cannula placed in the abdominal aorta with either 2% glutaraldehyde in 0.1M cacodylate buffer (pH 7.4) for fixation, 10% India ink in 0.9% saline and 0.1M phosphate (pH 7.4) for vessel tracing, or resin (Mercoximethylmethacrylate: catalyst, 4:1:0.3; Ladd Research Industries) for vascular corrosion casting. Infusion pressure was 100mm Hg. Fixed tissue was sectioned from epon-araldyte resin, and stained with toluidine blue for light microscopy, and lead and uranium for TEM. Ink injected tissue was photographed directly from saline-filled bladders illuminated from below. Resin-filled tissue was macerated in 5% KOH and distilled water. Casts were critical point dried, sputter coated with goldpalladium, and examined by routine SEM at 10 KV.

When Does Voice Have to be More Than Only Listening? Procedural Justice Effects as a Function of Confident Leadership

2010 ◽  
Vol 9 (2) ◽  
pp. 69-78 ◽  
Author(s):  
David De Cremer ◽  
Maarten Wubben
Keyword(s):  
Procedural Justice ◽  
Interaction Effect ◽  
Laboratory Experiments ◽  
Negative Emotions

The present research examined how voice procedures and leader confidence affect participants’ negative emotions and willingness to withdraw. It was predicted that receiving voice would be valued out of instrumental concerns, but only when the enacting leader was high in confidence. Two laboratory experiments indeed showed an interaction between type of voice (pre-decisional vs. post-decisional) and leader’s confidence (low vs. high) on participants’ negative emotions and willingness to withdraw. In particular, post-decision voice only led to more negative responses than did pre-decision voice when the enacting leader was high in confidence. Negative emotions mediated this interaction effect of type of voice on willingness to withdraw. Implications for integrating the leadership and procedural justice literatures are discussed.

Sign in / Sign up

Export Citation Format

Share Document