Effectiveness of lukewarm water compress on reduction of breast pain and breast engorgement among post-cesarean section mothers

Objective:The study aimed to assess the effectiveness of lukewarm water compress on breast pain and breast engorgement among post-cesarean primiparous mothers.Materials and Methods:This quasi-experimental posttest-only design was conducted with 60 post-cesarean section primiparous mothers between October 2018 and January 2019.A simple random sampling technique was used to allocate 30 participants to both experimental and control groups.The experimental group received lukewarm water compress using a sponge cloth for 20 min twice a day on the second,third,and fourth postnatal days.The control group received routine hospital care.Breast pain and engorgement were assessed using the Visual Analog Pain Scale and Breast Engorgement Assessment Scale on the third,fourth,and fifth postnatal days.Results:Significant differences were observed between the experimental and control groups on day 1 and day 3 in terms of breast pain and engorgement scores among post-cesarean section mothers(P<0.001).In addition,no statistically significant differences were found between sociodemographic and breastfeeding parameters and breast pain and engorgement(P>0.05).Conclusion:Lukewarm water compress is effective in reducing breast pain and engorgement in post-cesarean primiparous mothers.Future research can include randomized controlled trials to evaluate the effectiveness of different therapies in treating breast pain and engorgement.

Seismic response analysis of arch dam-water-rock foundation systems

The effect of water compressibility on the seismic responses of arch dams is not well understood.In this paper,a numerical model is developed with rigorous representation of the dynamic interaction between arch dam-water- rock foundation.The model is applied to the seismic response analysis of an arch dam with a height of 292m designed to a seismic intensity of IX.It is shown that consideration of the water compressibility clearly decreases the stress responses at key positions of the dam,while the added mass model gives a conservative estimate.

Modeling Virgin Compression of Reconstituted Clay at Different Initial Water Contents

The observations on compressibility of reconstituted clays show that the compression line with a higher initial water content lies above the compression line with a lower initial water content for a given clay. Hence there exists additional void ratio due to initial water contents among virgin compression lines（VCLs） of reconstituted clays. In this paper, the difference in void ratio caused by different initial water contents is investigated based on the empirical equation proposed by Liu and Carter（2000） for describing the differential void ratio at the same stress between natural and reconstituted clays. The mechanism of compressibility of reconstituted clays, when the stress level is larger than the remolded yield stress, is also discussed.

Development and application of multi-field coupled high-pressure triaxial apparatus for soil

The increasing severity of ground subsidence,ground fissure and other disasters caused by the excessive exploitation of deep underground resources has highlighted the pressing need for effective management.A significant contributing factor to the challenges faced is the inadequacy of existing soil mechanics experimental instruments in providing effective indicators,creating a bottleneck in comprehensively understanding the mechanisms of land subsidence.It is urgent to develop a multi-field and multi-functional soil mechanics experimental system to address this issue.Based soil mechanics theories,the existing manufacturing capabilities of triaxial apparatus and the practical demands of the test system,a set of multi-field coupled high-pressure triaxial system is developed tailored for testing deep soils(at depths of approximately 3000 m)and soft rock.This system incorporates specialized design elements such as high-pressure chamber and horizontal deformation testing devices.In addition to the conventional triaxial tester functions,its distinctive feature encompass a horizontal deformation tracking measuring device,a water release testing device and temperature control device for the sample.This ensemble facilitates testing of horizontal and vertical deformation water release and other parameters of samples under a specified stress conditions,at constant or varying temperature ranging from-40℃–90℃.The accuracy of the tested parameters meets the requirements of relevant current specifications.The test system not only provides scientifically robust data for revealing the deformation and failure mechanism of soil subjected to extreme temperature,but also offers critical data support for major engineering projects,deep exploration and mitigation efforts related to soil deformation-induced disaster.

Hydrodynamic Characteristics and Supercavity Shape of Supercavitating Projectiles Launched with Supersonic Speed

A supercavitating projectile is launched underwater with supersonic speed,and then,the speed decreases to transonic and subsonic conditions orderly because of the drag coming from surrounding water.The flow regime and hydrodynamic characteristics are significantly influenced by the flying speed,the influence laws in supersonic,transonic,and subsonic regions are totally different.These issues aren’t well studied.A numerical model consisting of VOF model,moving frame method and state equation of liquid is established to calculate the compressible supercavitation flow field,and validated by comparing with a published result.The influences of water compressibility and Mach number on supercavity shape and hydrodynamic characteristics are quantitatively summarized.The results show that the flying speed of supercavitating projectiles exerts significant influences on the flow regime,supercavity shape and hydrodynamic characteristics for the transonic and supersonic conditions.With the decrease of flying speed,the drag coefficient decreases gradually,and the dimensions of the supercavity near supercavitating projectiles significantly increases in the high-speed conditions.An underwater bow shock is numerically observed before the disk cavitator in supersonic condition.However,no obvious changes are found for the incompressible water cases with different speeds.For supersonic conditions,the supercavity near supercavitating projectiles of compressible water is smaller than that of incompressible water,the drag coefficient is larger,and the relative difference significantly increases with the flying speed.For the case of Ma 1.214,the relative difference of supercavity diameter at the tail section 3.98%,and the difference of the drag coefficient is 23.90%.

THE PROPERTIES OF SILICA FUME-MAGNESIUM OXYCHLORIDE CEMENT MATERIALS

The properties of a new magnesium Oxychloride cement (MOC) material formed by silica fume uniformly mix in MOC paste was presents. The influence of silica fume on the water resistance and compressive strength of MOC paste was invesigated in this study. It is shown that when 30 weight percent of silica fume is added to the MOC paste, a high strength and water resisting new material with 112MPa compressive strength and 1 00 water resisting coefficient could by obtained.

A Simple Mix Proportion Design Method Based on Frost Durability for Recycled High Performance Concrete Using Fully Coarse Recycled Aggregate

Durability design of recycled high performance concrete（RHPC） is fundamental for improving the use rate and level of concrete waste as coarse recycled aggregate（CRA）. We discussed a frostdurability-based mix proportion design method for RHPC using 100 % CRA and natural sand. Five groups of RHPC mixes with five strength grades（40, 50, 60, 70 and 80 MPa） were produced using CRA with four quality classes, and their workability, 28 d compressive strengths and frost resistances（measured by the compressive strength loss ratio and the relative dynamic modulus of elasticity） were tested. Relationships between the 28 d compressive strength, the frost resistance and the CRA quality characteristic parameter, water absorption, were then developed. The criterion of a CRA maximum water absorption limit value for RHPC was suggested, independent of its source and quality class. The results show that all RHPC mixes achieve the expected target workability, strength, and frost durability. The research results demonstrate that the application of the proposed method does not require trial testing prior to use.

SIMULATION OF HYDRAULIC TRANSIENTS IN HYDROPOWER SYSTEMS USING THE 1-D-3-D COUPLING APPROACH

Although the hydraulic transients in pipe systems are usually simulated by using a one-dimensional （l-D） approach, local three-dimensional （3-D） simulations are necessary because of obvious 3-D flow features in some local regions of the hydropower systems. This paper combines the 1-D method with a 3-D fluid flow model to simulate the Multi-Dimensional （MD） hydraulic transients in hydropower systems and proposes two methods for modeling the compressible water with the correct wave speed, and two strategies for efficiently coupling the 1-D and 3-D computational domains. The methods are validated by simulating the water hammer waves and the oscillations of the water level in a surge tank, and comparing the results ~with the 1-D solution data. An MD study is conducted for the transient flows in a realistic water conveying system that consists of a draft tube, a tailrace surge tank and a tailrace tunnel. It is shown that the 1-D-3-D coupling approach is an efficient and promising way to simulate the hydraulic transients in the hydropower systems in which the interactions between 1-D hydraulic fluctuations of the pipeline systems and the local 3-D flow patterns should be considered.