Impacts of anisotropy coefficient and porosity on the thermal conductivity and P-wave velocity of calcarenites used as building materials of historical monuments in Morocco

It is essential to study the porosity,thermal conductivity,and P-wave velocity of calcarenites,as well as the anisotropy coefficients of the thermal conductivity and P-wave velocity,for civil engineering,and conservation and restoration of historical monuments.This study focuses on measuring the thermal conductivity using the thermal conductivity scanning(TCS)technique and measuring the P-wave ve-locity using portable equipment.This was applied for some dry and saturated calcarenite samples in the horizontal and vertical directions(parallel and perpendicular to the bedding plane,respectively).The calcarenites were selected from some historical monuments in Morocco.These physical properties were measured in the laboratory to find a reliable relationship between all of these properties.As a result of the statistical analysis of the obtained data,excellent linear relationships were observed between the porosity and both the thermal conductivity and porosity.These relationships are characterized by relatively high coefficients of determination for the horizontal and vertical samples.Based on the thermal conductivity and P-wave velocity values in these two directions,the anisotropy coefficients of these two properties were calculated.The internal structure and the pore fabric of the calcarenite samples were delineated using scanning electron microscopy(SEM),while their chemical and mineral compositions were studied using the energy dispersive X-ray analysis(EDXA)and X-ray diffraction(XRD)techniques.

Effect of Irrigation Water Quality on Soil Hydraulic Conductivity

The effect of irrigation water quality on unsaturated hydraulic conductivity (HC) of undisturbed soil in field was studied.Results show that within the operating soil suction range (0-1.6 KPa) of disc permeameters,the higher the electric conductivity (EC) of irrigation water,the higher the soil HC became.The soil HC doubled when EC increased from 0.1 to 6.0ds m^-1.High sodium-adsorption ratio(SAR) of irrigation water would have an unfavorable effect on soil HC.Soil HC decreased with the increasing of SAR,especially in the case of higher soil suction.An interaction existed between the effects of EC and SAR of irrigation water on soil HC.The HC of unsaturated soil dependent upon the macropores in surface soil decreased by one order of magnitude with 1 KPa increase of soil suction.In the study on the effect of very low soluble salt concentration (EC=0.1 ds m^-1 of irrigation water on soil HC,soil HC was found to be lowered by 30% as a consequence of blocking up of some continuous pores by the dispersed and migrated clay particles.Nonlinear successive regression analysis and significance test show that the effects of EC and SAR of irrigation water on soil HC reached the extremely significant level.

Influence of Water Content on Conductivity and Piezoresistivity of Cement-based Material with both Carbon Fiber and Carbon Black

The influence of water content on the conductivity and piezoresistivity of cement-based material with carbon fiber （CF） and carbon black （CB） was investigated. The piezoresistivity of cement-based material with both CF and CB was compared with that of cement-based material with CF only, and the changes in electrical resistivity of cement-based material with both CF and CB under static and loading conditions in different drying and soaking time were studied. It is found that the piezoresistivity of cement-based material with both CF and CB has better repeatability and linearity than that of cement-based material with CF only. The conductivity and the sensitivity of piezoresistive cement-based material with both CF and CB are enhanced as the water content in piezoresistive cement-based material increases.

Capacity of Stem Water Conductivity for Two Eucalyptus (Eucalyptus urophylla) Plantations in South China

The sap flux density (SFD) was used as a measure of water capacity through stems of eucalyptus in this paper. It was found that daily SFD increased with daily vapor pressure deficit (VPD) in nonlinear regression Y = AX3 + BX2 + CX + D (R2 = 0.702 1, n = 135, p = 0.01) at both sites (Hetou and Jijia) in the Leizhou Peninsula, Guangdong Province, China, where Y was daily SFD, X was mean daily VPD, A, B, C, D were constants. But extremely high VPD might limit stem water conductivity. The environmental factors, such as air vapor pressure deficit (VPD), solar radiation (RAD), etc., were the main determinants of SFD for E. urophylla plantations. The upper threshold of diurnal SFD was 51.5555.65 mLcm2h1 under the selected extremely high environmental conditions.

Influence of the electrolyte conductivity on the critical current density and the breakdown voltage

The work investigates influence of the electrolyte conductivity on the onset of partial contact glow discharge electrolysis(CGDE)in a water electrolysis.Critical current density(CCD)and breakdown voltage were measured together with in situ observation of hydrogen bubble behavior,whose influence has not been focused on.For a fixed current during normal electrolysis,hydrogen coalescence adjacent to cathode surface was invigorated at a lower conductivity.Photographic analyses elucidated the hydrogen coalescence characteristics by quantifying size and population of detached hydrogen bubbles.The CCD increased about 104% within given range of conductivity(11.50-127.48 mS·cm^(-1))due to impaired bubble coalescence,which delays hydrogen film formation on the cathode.Meanwhile,decreasing trend of breakdown voltage was measured with increased conductivity showing maximum drop of 74%.It is concluded that onset of partial CGDE is directly affected by hydrodynamic bubble behaviors,whereas the electrolyte conductivity affects the bubble formation characteristics adjacent to cathode electrode.

Factors Influencing the Thermal Conductivity of Silt in the Yellow River Delta

The thermal conductivity of marine sediments is an important thermophysical parameter in the study of seafloor heat flow and marine engineering construction.Understanding the effect of thermal conductivity of marine sediments in the environment has a major engineering value and theoretical significance.In this work,a modified test method was used to measure the thermal conductivity of silt in the Yellow River Delta under different void ratios,moisture contents,temperatures,and salinities.Results showed that the thermal conductivity of silt in the Yellow River Delta decreased with the increase in the void ratio and increased with the water content.Compared with sand and clay,silt in the Yellow River Delta was the least affected by the void ratio and moisture content.Under low temperatures,the heat transfer of soil was controlled by the average velocity of the phonons;therefore,the thermal conductivity of silt in the Yellow River Estuary increased with temperature.The thermal conductivity of pore water decreased with increasing salinity.Moreover,certain salinity levels resulted in a phenomenon known as the‘compressing twin electrical layer’,which led to an increase in the contact area between soil particles.With the increase in salinity,the thermal conductivity of silt in the Yellow River Delta experiences an initial decline and a subsequent increase.The proposed thermal conductivity test method is more accurate than the existing technique,and the findings provide a basis for further study on the thermal characteristics of submarine sediments.

Sensitive Determination of Metal Ions in Drinking Water by Capillary Electrophoresis Coupled with Contactless Conductivity Detection Using 18-Crown-6 Ether and Hexadecyltrimethylammonium Bromide as Complexing Reagents

A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K+, Na+, Mg2+, Sr2+, Ca2+ in drinking water. 18-Crown-6 ether and Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents. The effects of electrolyte additives, citric acid buffer solution, and other separation conditions of CE were comprehensively investigated and carefully optimized. The best results were obtained in a running buffer solution composed of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH 3.5. Under these conditions, a complete separation of five metal ions was successfully achieved in less than 12 min. The limits of detection for the optimal procedure were determined to be in the range of 0.02 - 0.2 mg·L-1. The repeatability with respect to migration times and peak areas, expressed as relative standard deviations, was better than 2.3% and 5.1%, respectively. Evaluation of the efficiency of the methodology indicated that it was reliable for the determination of metal ions in six different brands of drinking water samples.

Boosting overall saline water splitting by constructing a strain-engineered high-entropy electrocatalyst

High-entropy materials(HEMs),which are newly manufactured compounds that contain five or more metal cations,can be a platform with desired properties,including improved electrocatalytic performance owing to the inherent complexity.Here,a strain engineering methodology is proposed to design transition-metal-based HEM by Li manipulation(LiTM)with tunable lattice strain,thus tailoring the electronic structure and boosting electrocatalytic performance.As confirmed by the experiments and calculation results,tensile strain in the LiTM after Li manipulation can optimize the d-band center and increase the electrical conductivity.Accordingly,the asprepared LiTM-25 demonstrates optimized oxygen evolution reaction and hydrogen evolution reaction activity in alkaline saline water,requiring ultralow overpotentials of 265 and 42 mV at 10 mA cm−2,respectively.More strikingly,LiTM-25 retains 94.6%activity after 80 h of a durability test when assembled as an anion-exchange membrane water electrolyzer.Finally,in order to show the general efficacy of strain engineering,we incorporate Li into electrocatalysts with higher entropies as well.

Formulation and Its Verification of Conductivity for Uniform Turbid Water

For measurement of sediment spatial concentration of nearshore seawater, a turbid water system with several. kinds of particles is investigated from the viewpoint of the characteristics of particles. Firstly, the classical physical and chemical conductivity formula is extended to macro-particle (such as sand) conductivity formula. Secondly, the Fricke formula suitable for only one kind of particles is extended to the conductivity formula suitable for several kinds of particles.. Finally, the multi-particle conductivity formula is applied to the measurement of sediment spatial concentration.

EFFECT OF WATER ON THE CONDUCTIVITY OF PPQ (ClO_4^-) COMPLEX

The preparation of conducting PPQ film was first reported in the previous paper. It is very interesting that this film is highly sensitive to moisture in air. The hydration and dehydration of the film are accompanied by change not only in color but also in conductivity and UV-visible spectrum. The conducting PPQ is reduced to PPQ and loses its conductivity after being soaked in water.

Atypical Variations of Water Conductivity Prior to Tectonic Earthquakes

Within the framework of precursor events related to earthquakes, this paper analyzes the possible effect on the aquatic environment of the surrounding energy that accompanies earthquakes, particularly in the area where oceanic and continental plates collide (Cocos Plate and North American Plate, south of Mexico). As a preamble, the types of precursor events, characteristics, and their possible origin are described. A project was designed under the assumption that in areas with high frequency and intensity seismicity there is an electrical and electromagnetic potential promoter which is detectable and assessable indirectly by measuring water conductivity behavior, which also may have atypical variations of data;the outcome of intensive conductivity monitoring in different settings, natural as well as manmade (wellsprings, artesian well and a cistern), are presented herein. The results of the conductivity monitoring for seven months, highlight two patterns in data behavior: one pattern shows the subtle dependence of data behavior on the geographic location of data monitoring instruments, revealing that could have a slight relationship between areas with increased seismic frequency and intensity and the presence of atypical conductivity variations. Another pattern reveals the possible relationship between atypical variations in conductivity and subsequent earthquake events;a total of 241 seismic events were analyzed and 59 of them are provided as evidence related with patterns mentioned.

Dynamics of Potable Well Water Quality in Key Mining Chiefdoms in Kono District, Eastern Sierra Leone

Groundwater is increasingly being used due to its universal availability and generally good quality. However, the risk of contamination of groundwater due to various human activities such as mining is equally increasing across the globe. In this study, the physical parameters of potable well waters in the key mining areas in Nimikoro and Tankoro Chiefdoms in Kono District were analyzed for compliance with drinking water quality standard. To do this, both unpurged and purged well water samples were collected once every month for a period of one year. Some of the well water properties like temperature, Total Dissolved Solids (TDS) and Electrical Conductivity (EC) were measured on site and others determined in the laboratory. The data collected from the laboratory analyses were statistically analyzed in MS Excel, SPSS and ArcGIS environments for quality trends in time-space fabric. The results showed that well water quality in the study area generally fell short of drinking water quality standards of Sierra Leone and WHO. There were high temperature and turbidity during the dry season and then high TDS and EC during the rainy season. Temperature and turbidity also significantly influenced well water quality in the study area, much more than TDS and EC. The implications for drinking water of lower quality than the standard could be huge for the local population and therefore needs the attention of stakeholders in the study area and decision makers in the country.

High Conductivity Water Treatment Using Water Surface Discharge with Nonmetallic Electrodes

Although electrohydraulic discharge is effective for wastewater treatment,its application is restricted by water conductivity and limited to the treatment of low conductivity water. For high conductivity water treatment,water-surface discharge is the preferred choice.However. the metallic electrodes are easily corroded because of the high temperature and strong oxidative environment caused by gas phase discharge and the electrochemical reaction in water.As a result. the efficiency of the water treatment might be affected and the service life of the reactor might be shortened.In order to avoid the corrosion problem,nonmetallic electrode water-surface discharge is introduced into high conductivity water treatment in the present study.Carbon-felt and water were used as the high voltage electrode and ground electrode,respectively.A comparison of the electrical and chemical characteristics showed that nonmetallic electrode discharge maintained the discharge characteristics and enhanced the energy efficiency,and furthermore,the corrosion of metal electrodes was avoided.

Effects of physical properties on electrical conductivity of compacted lateritic soil

Natural soils of various types have different electrical properties due to the composition,structure,water content,and temperature.In order to investigate the electrical properties of lateritic soil,electrical conductivity experiments have been conducted on a self-developed testing device.Test results show that the electrical conductivity of laterite increases with the increase of water content,degree of saturation and dry density.When the water content is below the optimum water content,the electrical conductivity of soils increases nonlinearly and the variation rate increases dramatically.However,when the water content,degree of saturation,or dry density increases to a certain value,the electrical conductivity tends to be a constant.In addition,soil electrical conductivity increases with the increase of temperature,and it is observed that the electrical conductivity decreases with the increase of the number of wetting–drying cycles.

Modulation of leaf conductance by root to shoot signaling under water stress in Arabidopsis

Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is available for the model plant, Arabidopsis, whose adoption has great significance for further probing the molecular aspects of long distance stress signals. Here, we introduced the es- tablishment of techniques for investigations of root to shoot signals in Arabidopsis. Stomata! movements in relation to root signals were probed by using these techniques. The results show that Arabidopsis is a suitable plant species for partial roots drying （PRD） experiments. In the PRD system, while no significant differences were found in leaf water potential between well-watered and stressed plants, water stress led to a decrease in leaf conductance, which suggests a regulation of stomatal movements by root to shoot signals. While water stress caused a significant increase in the concentration of sap abscisic acid （ABA） of xylem, no increase in xylem sap pH was observed. Moreover, the increase in the ABA content of xylem coincided with the decrease in leaf conductance, which suggests a possible role of ABA in the regulation of stomatal movements. Infrared temperature images showed that leaf tem- peratures of PRD plant were higher compared with those of well-watered plants, which further indicates that stomatal movements can be modulated by root signals. The confirmation of root to shoot signaling in Arabidopsis has established a basis for further inves- tigation into the molecular mechanisms of the root to shoot signaling under water stress.

An unusual network of α-MnO_(2) nanowires with structure-induced hydrophilicity and conductivity for improved electrocatalysis

Nanowires with anisotropic morphologies have been applied in various scientific and technological areas.It is also widely employed to fabricate nanowires into high-dimensional superstructures(arrays,networks etc.)to overcome the shortcomings of low-dimensional nanowires.However,typical strategies for constructing these superstructures are restricted to complicated and harsh synthetic conditions,not to mention unique 3D structures with advanced properties beyond common superstructures.Herein,we report an unusual network ofα-MnO_(2)nanowires with structure-induced hydrophilicity and conductivity.In the network,the nanowires are interconnected from all directions by nodes,and the 3D network structure is formed from the endless connection of nodes in a node-by-node way.The unique network structure brings about high hydrophilicity and conductivity,both of which are positive factors for an efficient electrocatalyst.Accordingly,the α-MnO_(2) network was tested for electrocatalytic water oxidation and showed significantly enhanced activity compared with isolatedα-MnO_(2)nanowires and 3Dα-MnO_(2)microspheres.This study not only provides a synthetic route toward an advanced network structure but also a new idea for the design of materials for electrochemistry with both efficient mass diffusion and charge transfer.

Preparation and Properties of Water-based Conducting Polyaniline

A convenient way to prepare water soluble or water dispersible conducting polyaniline was developed by employing protonic acid dopants containing hydrophilic ethyleneoxide oligomer as counter-ion. The conducting polyaniline possesses electrical conductivity in the range of 10^(-3) to 10^(-2)S/cm depending on the chosen dopant, and it displays an excellent electrochemical redox reversibility in non aqueous systems.

Research of Water Response under the Action of the Infrared Human Body Radiation by Water Conductometric Sensors

Non-equilibrium thermal and biothermal radiation generated by heated solid materials and hematothermal living organisms are studied by water conductometric sensors. Engineering aspects and physical features of developed water conductometric sensors are given. Procedure and measuring technique are described. Our experiments show the anomalous behavior of water conductivity and associated differential parameters under water heating by biological objects compared with traditional heating sources. Water response to human action strongly depends on psychophysiological and psychoemotional state of the person. Moreover the responses to the action by left and right human hands are substantially different and as a rule are specific to the gender. The possible physicochemical mechanisms of such anomalous water behavior are studied. It is suggested that the observed effects are associated with resonant excitation of vibration-rotation energy levels of water under the influence of bioradiation generated by human organism consisting of approximately 70% water. The results obtained have good perspectives for future applications in different fields of human activity.

Assessment of the Total Organic Carbon and Conductivity in Consecutive Dyeings with Reactive Dyestuffs Using Treated Effluent by UV/H202 Photocatalysis

The paper was monitored the conductivity （g.L＂l of NaCI）, the absorbances values （Abs） and the amount of TOC （total organic carbon）, before and after five consecutive dyeings made with reuse water, obtained from treated effluent by UV/H202 photocatalysis. All rates of decolorization were above 92%, the removal of total organic carbon was above 89% in all treatments and the economy of NaCI was from 3.10 in the first recipe, 3.17 in the second, 3.49 in the third, 3.79 in the fourth and 4.05 in the fifth recipe. The five dyeings compared with same dyeings made with deionized water presented a color deviation （AE＊） below 1. The conventional dyeings would consume 80 L/kg against 40 L/kg used in the dyeing process proposed in this study, representing a great economy of water, with no discharge of effluents.

Laboratory and field experiment on measurement of soil thermal conductivity by probe method

The authors presented a new measuring method of the soil thermal conductivity,the probe method,which is designed and made based on the theory of line heat source. This method is used to measure thermal conductivity of coarse sand,fine sand and silty clay in different water contents. The results that measured by the probe method are well consistent with those of QTM-D_2. The soil thermal conductivity increases in different levels with the increase of the water content. Compared the soil thermal conductivity measured by the probe method in laboratory with in-situ experiment,it shows that the measuring gap gradually increases with the increase of the depth. The reason is that the in-situ measuring thermal conductivity can reflect the actual situation of the soil mass.