Preloading Effect On The Strength of Cement Mass Mixing Treated Salty Sand

Existing problematic sub-layers in mixing technologies are a challenge, and for the first time, the effects of salt sub-layers in mass mixing technology have been investigated in this study for sandy salt in the southwest of Iran. This paper discusses the influence of adding various cement contents, Aw, and imposing different preloading values on the salty sand soil. First, salt and sand samples were dried, then, 90 % sand was mixed with 10% salt. After that, 30 % water was mixed thoroughly with the mixture of salty sand to obtain slurries. Cement slurry at a water-cement ratio (w/c) of 0.6 was then added to the sample and thoroughly mixed. The amount of cement in a slurry form that was added to the salty soil was 2, 4, 6, 8, and 10% by mass of dry soil. Each treated soil preloaded by 0, 9, and 45 kPa. After 120 days, the unconfined compressive strength of the sample was determined. Furthermore, by Scanning Electronic Microscope, SEM, the microstructures of treated samples were analyzed. At the end Unconfined Compression Strength, UCS, test results normalized to the non-preloaded treated soil. By increasing cement content, the effect of preloading in increasing UCS will decrease. In the SEM images for Aw=2%, the effect of preloading indicates porous shape for non-preloaded samples. Vice versa by Aw=8%, porous shape in the SEM images will disappear. In the end, treatability studies of pure salt in the thick layer have been investigated.

Inorganic salt hydrates and zeolites composites studies for thermochemical heat storage

Salt hydrates (MgSO4 and ZnSO4) impregnated in zeolites, offer a variety of improvements, mostly providing a large surface area for salt hydrates and water molecules. A composite of 5 and 10% of salt contents were prepared as heat storage materials. The study’s finding showed that dehydration enthalpy of MgSO4 (1817 J g−1) and ZnSO4 (1586 J g−1) were 10 and 15% improved than pure salt hydrates by making composites. During the hydration process of composites, the water sorption is 30–37% improved and further the increasing of salt contents in composites enhances more 10% increase in the water resorption. The cyclicability of MgSO4/zeolite and ZnSO4/zeolite were 45 and 51% improved than their corresponding pure salt hydrates. The effect of humidity on the water sorption result reveals that composites of MgSO4/zeolite and ZnSO4/zeolite at 75% relative humidity (RH), the mass of water are 51 and 40% increase than 55% RH.

Co-crystals, Salts or Mixtures of Both? The Case of Tenofovir Alafenamide Fumarates

Tenofovir alafenamide fumarate (TAF) is the newest prodrug of tenofovir that constitutes several drug products used for the treatment of HIV/AIDS. Although the solid-state properties of its predecessor tenofovir disoproxil fumarate have been investigated and described in the literature, there are no data in the scientific literature on the solid state properties of TAF. In our report, we describe the preparation of two novel polymorphs II and III of tenofovir alafenamide monofumarate (TA MF2 and TA MF3). The solid-state structure of these compounds was investigated in parallel to the previously known tenofovir alafenamide monofumarate form I (TA MF1) and tenofovir alafenamide hemifumarate (TA HF). Interestingly, the single-crystal X-ray diffraction of TA HF revealed that this derivative exists as a co-crystal form. In addition, we prepared a crystalline tenofovir alafenamide free base (TA) and its hydrochloride salt (TA HCl), which enabled us to determine the structure of TA MF derivatives using 15N-ssNMR (15N-solid state nuclear magnetic resonance). Surprisingly, we observed that TA MF1 exists as a mixed ionization state complex or pure salt, while TA MF2 and TA MF3 can be obtained as pure co-crystal forms.

Morphological and Structural Evaluation of Hydration/Dehydration Stages of MgSO4 Filled Composite Silicone Foam for Thermal Energy Storage Applications

Salt hydrates, such as MgSO4∙7H2O, are considered attractive materials for thermal energy storage, thanks to their high theoretical storage density. However, pure salt hydrates present some challenges in real application due to agglomeration, corrosion and swelling problems during hydration/dehydration cycles. In order to overcome these limitations, a composite material based on silicone vapor-permeable foam filled with the salt hydrate is here presented. For its characterization, a real-time in situ environmental scanning electron microscopy (ESEM) investigation was carried out in controlled temperature and humidity conditions. The specific set-up was proposed as an innovative method in order to evaluate the morphological evolution of the composite material during the hydrating and dehydrating stages of the salt. The results evidenced an effective micro-thermal stability of the material. Furthermore, dehydration thermogravimetric/differential scanning calorimetric (TG/DSC) analysis confirmed the improved reactivity of the realized composite foam compared to pure MgSO4∙7H2O.

Diffuse reflectance spectroscopic analysis of barium sulfate as a reflection standard within 173–2500 nm: From pure to sintered form

The use of barium sulfate (BaSO4) as a low-cost reflectance standard has been documented for some time. In its pure salt form, the optical characteristics do have advantages compared to laboratory-grade sintered polytetrafluoroethylene (PTFE). However, its practical use has little advantage against the stability of PTFE. In this paper, a process of producing pelletized BaSO4, and characterization of its optical reflectance properties is reported. In its sintered form, data-driven analysis shows that BaSO4 is a commendable low-cost, high-reflection and a high-consistency material. The current sintered forms, though crude, registers a relatively stable texture to withstand minor mechanical stress, while having up to an average 92% reflectivity across the UV-VIS-NIR range (173–2500 nm) compared to a PTFE reflection standard.

Rheological Characteristics of Molten Salt Seeded with Al2O3 Nanopowder and Graphene for Concentrated Solar Power

HITEC salt (NaNO2-NaO3-KNO3) and solar salt (NaO3-KNO3) are typical molten salts used in concentrated solar power. Adding nanoparticles is an effective method to improve the thermo-physical properties of pure salt. It is indispensable to experimentally study the rheological behaviours of salt seeded with nanoparticles, which can increase the specific heat capacity of pure salt. In this work, the viscosities of HITEC salt were measured with different shear rates in the temperature range of 200 °C to 450 °C firstly, while those of solar salt were measured in the temperature range of 250 °C to 500 °C. The experimental data showed reasonable agreement with the literature correlations, which verify the Newtonian behaviours of pure salts. The evolutions of the viscosities of nanocomposites in the same temperature range were measured and analysed, where the nanocomposites were synthesized with 1 wt.% or 2 wt.% Al2O3 nanopowder and graphene, respectively. Results showed that the addition of Al2O3 nanopowder had relatively little effect on viscosity, and the variations were about −35.4%~8.1% for the HITEC salt nanocomposites and −9.2%~68.1% for the solar salt nanocomposites. While graphene would apparently increase the viscosities of HITEC salt and solar salt, HITEC salt with the addition of graphene showed slight non-Newtonian fluid behaviour.

COASTAL PROTECTION OF GOTVAND RESERVOIR DAM: ELECTRICAL CONDUCTIVITY PERFECTION OF SALTY DOMES

The Gotvand reservoir dam is located at SW of Iran where the Karun River orients from the Zagros Mountains. The nominal volume is 5,500 million cubic meters. It is a rock-fills dam with clay core. The height of crown is about 180 m with 130 m normal water depth. Depth from bottom (0-30 m), the water layer’s electrical conductivity (EC) will be as 150,000 to 85,000 mµ/cm. Also the EC will decrease from depth (85-30 m) corresponding the water layer’s EC between 85,000 to 20,000 µm/cm. Finally, at depth (30-0.0 m) the EC is controlled with values (15,000-1,000 µm/cm). The salty domes will produce unexpected salty sediments into reservoirs. Consulting engineering said that more than 8,000,000 tons of pure salt sediments were interned into the Gotvand Lake reservoir from 2011 through 2015. If this regime of salty material continues, downstream agricultural lands will completely disturb and disuses. Turk salty concrete (SC) could present innovative solution to reduce salty feed in lake. It is based on the chemical reaction of salt-clay-cement that salty volumes could be stabled through special material injection inside the domes. Sliding resistance will be increased by SC injection in the salty dome layers. Finally, the salty sediment should be stabled by SC injection in the old mine Anbal salt dome. SC may be designed to cementize salty domes through powder of bentonite clay, type-II cement, water, and Shushtar ceramic clay.

The Effect of Differences in the Diffusion Coefficients of Components on the Onset of Convection in Isothermal Multicomponent Systems

Two series of experiments on the formation of convective flows in multicomponent liquid and gaseous mixtures are considered. In the first series, the convective structures arising during the diffusion of a binary aqueous solution of salt and sugar in an aqueous solution of pure salt were studied using the schlieren method. The observed behavior of convective cells corresponds to the instability similar to the "finger structures". In the second series, the experiments were conducted to determine the effective diffusion coefficients as a function of pressure in gas mixtures 0.5504 CH4 + 0.4496 Ar – N2 and 0.5994 H2 + 0.4006 Ar – N2. Our experiments have shown that the onset of convective flows both in liquid and gaseous multicomponent mixtures is due to the difference in the interdiffusion coefficients of the components. The experimental data for the ternary gas mixtures are described in the framework of the linear theory of stability.