Investigation of Deformation Pattern and Movement Law of the Huge-Thick Conglomerate Stratum by a Large-Scale 3D Model Test with Distributed Optical Fiber Sensor Monitoring

Mining activities under the circumstances of huge-thick stratum occurrence commonly result in dynamic response of the working face. It is crucial to understand the rock failure and movement of the huge-thick stratum in order to prevent dynamic hazards. This paper introduces distributed optical fiber sensor (DOFS) monitoring into a large-scale model test to investigate the deformation pattern and movement law of the huge-thick conglomerate (HTC); the monitoring results are verified by numerical simulation. The results indicate that DOFS monitoring captures the spatiotemporal evolution of zoning development in the overburden deformation. The deformation field of HTC is illustrated, and there exists a strain basin that can be used to estimate the movement law of HTC. The average strain variability Ex, a new homogenization index for characterizing the overburden deformation, is proposed to describe the broken rules of the HTC. The numerical simulation proves the feasibility of the DOFS monitoring method and the correctness of the deformation pattern and movement law. This study provides efficient methods for DOFS monitoring utilization to investigate mining engineering problems and could be beneficial for unearthing the mechanisms of deep ground rock deformation.

Breaking and Instability Movement Characteristics of High-Position Double-Layer Hard Thick Strata due to Longwall Mining

With multilayer hard roof occurring above the mining area, the strata behaviors will be significantly affected by their special characteristics and interaction. In this paper, relying on the mining background of panel 1061 of a coalmine, the breaking instability of double-layer hard thick strata (DLHTS) and the precursory information of disasters are studied by using theoretical analysis, numerical simulation, and physical simulation. Results show that the DLHTS have bearing, blocking, and controlling effects. Prior to DLHTS breaking, the horizontal development of stress concentration zone and plastic zone can be controlled, and the overburden movement is gentle, while during the breaking process, the stress drops abruptly, the plastic zone expands longitudinally rapidly, the overburden moves notably, and the energy release is sharp, which is likely to directly cause strong dynamic pressure. Moreover, the DLHTS can interact with and influence each other; that is to say, the breaking of lower magmatic rock (LMR) can provide sufficient space for that of upper magmatic rock (UMR), while the UMR breaking can promote the LMR periodic breaking in turn and cause its secondary instability, thereby easily causing complex or composite dynamic disasters’ formation. Hence, compared with single hard thick stratum occurrence, the strata behaviors affected by DLHTS breaking and instability are normal and more intense. Study results can provide a scientific basis for the prevention and control of dynamic disaster with hard thick stratum occurrence and important guidance value for promoting safe and efficient production of coalmines.

The Bearing Capacity Evaluations of a Spread Footing on Single Thick Stratum or Two-Layered Cohesive Soils

Nowadays many countries plan to increase the percentages of renewable energies by developing offshore wind power. Due to the large sizes of offshore foundations, such as spudcan footings of jack-up barges or pile anchors of wind turbines, the affected soil depth range caused by the foundation under loading can be relatively deep, so the affected range may include a single thick layer or stratified soils. This paper utilizes limit analysis and FLAC numerical simulation to investigate the bearing capacity of a footing on single thick stratum or two-layered cohesive soils. Under nature deposition condition, the undrained shear strength of most cohesive soil approximately increases linearly as the depth increases. The closed-form upper bound solutions of fully rough or fully smooth footings on thick cohesive soils are provided, for the purpose of fast evaluations in practical engineering, and the outcomes are within the results from the FLAC simulation and slip circle method. The problems of punch-through shear failure or soil squeezing could be critical for two-layered soils under some conditions, and the associated bearing factors and the failure mechanisms from different methods are demonstrated and discussed in the article.

TRANSMISSION COEFFICIENT OF POWER DENSITY INTO SKIN TISSUE BETWEEN 6 AND 300 GHZ

The latest electromagnetic safety guidelines define transmitted or epithelial power density as the basic restriction above 6 GHz. In this note, we derive an approximation for a conservative transmission coefficient for quasi plane wave incidence as a function of the frequency for the normal component of the Poynting vector with respect to the evaluation plane or tissue surface |Sz inc| and for its modulus ||Sinc||. The maximum transmission coefficient for the normal component of the Poynting vector ${\boldsymbol{T}}_{\mathbf{z}}^{\mathbf{max}}$ is 1 independent of tissue composition and frequency. Approximations of ${\boldsymbol{T}}_{\mathbf{total}}^{\mathbf{max}}$ normalized to ||Sinc|| for thin and thick stratum corneum are provided allowing higher exposures. These approximations allow to conservatively demonstrate compliance with basic restrictions when quasi plane-wave conditions are locally satisfied and enhancement effects of standing waves between source and body can be neglected. The reported results are important to regulators and standardization bodies regarding revisions of compliance requirements and safety guidelines.

Dermaroller in dermatology and cosmetology

Dermaroller is a novel therapeutic modality in dermatology. Through physical trauma from needle penetration, dermaroller induces a wound healing cascade with mild temporary damage to the epidermis. This allows for the enhancement in the absorption of topical therapies across the thick stratum corneum. Dermaroller has become increasingly utilized over the last several years as it is a relatively simple procedure that is cost effective, well tolerated and offers cosmetic and therapeutic benefits. The ability to treat localized areas of disease made it popular in acne scars, alopecia, striae, melasma, actinic keratoses. The procedure has few adverse sequelae compared to other therapies, is highly effective and a viable resurfacing option for color of skin.

Significance Testing of Archeological Site 41SR242, The Cornelio Alvarez Sr. Site, Starr County, Texas

The Texas Department of Transportation (TxDOT), conducted National Register of Historic Places (NRHP) eligibility testing of the Cornelio Alvarez Sr. site (41SR242) as part of the State Loop (SL) 195 project (Project) (CSJ: 3632-01-001) in Starr County, Texas. Subsequent to the field investigations, SWCA Environmental Consultants (SWCA) conducted artifact analysis, reporting, and curation preparation for the multi-component historic and prehistoric site. Investigations were conducted in compliance with Section 106 of the National Historic Preservation Act (54 United State Code 30601) and the Antiquities Code of Texas (9 Natural Resources Code). The investigations assessed the site’s eligibility for listing on the NRHP (36 Code of Federal Regulations 60.4) and for designation as a State Antiquities Landmark (SAL; 13 Texas Administrative Code 26.8, 26.12). Christopher W. Ringstaff served as Principal Investigator under Texas Antiquities Permit Number 7912. TxDOT conducted the field investigations were from February 20–24, 2017, and April 10–14, 2017. Site 41SR242 is primarily a Middle to Late Archaic site with lesser Late Prehistoric and perhaps earlier components. The open occupational site is located on an upland margin landform in a tributary valley a few miles from the Rio Grande. The investigations revealed material assemblages consisting of diffusely scattered burned rock, debitage, and lithic tools, which were predominantly recovered from a 30- to 50-cm-thick stratum of mixed artifacts. However, a few concentrations of artifacts were identified, and each location yielded isolated intact features. Formation and post-depositional processes are generally not conducive to preservation of intact archeological surfaces, patterns, or site structure. Although the overall site lacks integrity and potential data yield, isolated discrete behavioral loci are present. Therefore, site 41SR242 is recommended as eligible for the NRHP and as an SAL. This recommendation pertains to the portions of the site within the APE. The site extends beyond the APE, and the areas outside of the APE have not been evaluated.

Morphology and composition play distinct and complementary roles in the tolerance of plantar skin to mechanical load

Plantar skin on the soles of the feet has a distinct morphology and composition that is thought to enhance its tolerance to mechanical loads, although the individual contributions of morphology and composition have never been quantified. Here, we combine multiscale mechanical testing and computational models of load bearing to quantify the mechanical environment of both plantar and nonplantar skin under load. We find that morphology and composition play distinct and complementary roles in plantar skin’s load tolerance. More specifically, the thick stratum corneum provides protection from stress-based injuries such as skin tears and blisters, while epidermal and dermal compositions provide protection from deformation-based injuries such as pressure ulcers. This work provides insights into the roles of skin morphology and composition more generally and will inform the design of engineered skin substitutes as well as the etiology of skin injury.