Water Absorption Measurements Research Articles

Development of 3D printed nanomaterials for restoration of exterior artworks

Despite the great potential of 3D printing technologies coupled with nanotechnologies, just few studies are present in the scientific literature. Application of nanocomposites materials for 3D printing in the field of cultural heritage restoration, is a promising approach to obtain novel and functionalized materials for the artworks element to be recreated. In this context, the present work aims to study innovative nanocomposites materials suitable for the considered application. A commercial PLA filament was additivated with SiC, SiO2 and TiO2 nanoparticles, synthetized by CO2 laser pyrolysis. Nanocomposite filaments were produced by a co-rotating twin-screw extruder and specimens were produced by 3D printing and analysed against their mechanical and hydrophobic properties by means of tensile tests and water absorption and contact angle measurements, respectively.

Obsidian Hydration Dating: Summary and Status of a Physics-Based Approach

ABSTRACT Obsidian hydration dating (OHD) is a method of computing archaeological ages based on measuring water absorption by obsidian artifacts, and is widely used in the western United States. This abstract provides a single resource for the OHD user, including advances over the past decade. We describe obsidian mineralogy as it affects OHD; the effects of structural water content on hydration; the mathematical form of the hydration law; methods to control for structural water content and temperature history; methods for computing hydration rates; an analysis of error sources; and a method for conducting an OHD analysis. We address OHD as currently practiced in the western United States, based on optical microscopy, and do not describe newer, experimental methods such as Secondary Ion Mass Spectrometry or infrared (IR) spectroscopy. An associated OHD workbook in MS Excel is available on the website of the International Association for Obsidian Studies.

Development of Salmon Sperm DNA/Regenerated Silk Bio-Based Films for Biomedical Studies on Human Keratinocyte HaCaT Cells under Solar Spectrum.

In this study, we fabricated adhesive patches from silkworm-regenerated silk and DNA to safeguard human skin from the sun's rays. The patches are realized by exploiting the dissolution of silk fibers (e.g., silk fibroin (SF)) and salmon sperm DNA in formic acid and CaCl2 solutions. Infrared spectroscopy is used to investigate the conformational transition of SF when combined with DNA; the results indicated that the addition of DNA provides an increase in the SF crystallinity. UV-Visible absorption and circular dichroism spectroscopy showed strong absorption in the UV region and the presence of B-form of DNA once dispersed in the SF matrix, respectively. Water absorption measurements as well as thermal dependence of water sorption and thermal analysis, suggested the stability of the fabricated patches. Biological results on cellular viability (MTT assay) of keratinocyte HaCaT cells after exposures to the solar spectrum showed that both SF and SF/DNA patches are photo-protective by increasing the cellular viability of keratinocytes after UV component exposure. Overall, these SF/DNA patches promise applications in wound dressing for practical biomedical purposes.

Microstructure, tensile strength and shear strength of aggregate-mortar interface: Effect of aggregate mineralogy

This work aims to study the mechanical properties of the interfacial transition zone (ITZ) through both experimental tests and microstructural observations. The study considers a mortar with water-cement ratio of 0.58 and four types of aggregates: sandstone, granite, and two different types of limestone with varying water absorption coefficients. Chemical compositions, physical characteristics, and surface micromorphology of the four aggregates were evaluated using X-ray diffraction (XRD), thermogravimetric analysis (TGA), and water absorption measurements as well as SEM observations. Experimental setups were developed to investigate the bonding behavior of the aggregate-mortar interface. The bonding strength between granite and mortar through direct tensile test varied from 51% to 69% of tensile strength of mortar from young age to mature, while 61% to 74% for sandstone, 48% to greater than 90% and 81% to greater than 102% averagely for black and white limestone respectively. The fact of failure in the bulk mortar indicates ITZ adhesion for limestones may equal or exceed the mortar tensile strength generally from 28-day age. This conclusion is consistent with the results obtained by slant shear test. The significant difference of adhesion behavior of ITZ between two limestones due to their water absorption capability. High-water absorption turns out to be beneficial in forming a strong chemical bond at early age, however, the mineralogy remains the pivot under same surface condition. This chemical bond is evidenced by the failure pattern and morphology of the aggregate surface after failure and the presence of a dense accumulation of portlandite and C-S-H under SEM.

Sodium Salt of Partially Carboxymethylated Sodium Alginate-Graft-Poly(Acrylonitrile): II Superabsorbency, Salt Sensitivity and Swelling Kinetics of Hydrogel, H-Na-PCMSA-g-PAN.

The water absorption measurements of a novel superabsorbent anionic hydrogel, H-Na-PCMSA-g-PAN, has been reported first time in water with a poor conductivity, 0.15 M saline (NaCl, CaCl2, and AlCl3) solutions, and simulated urine (SU) solutions at various times. The hydrogel has been prepared by the saponification of the graft copolymer, Na-PCMSA-g-PAN (%G = 316.53, %GE = 99.31). Results indicated that as compared to the swelling capacity values evaluated in water with a poor conductivity, the ability of the hydrogel to swell in various saline solutions with the same concentration is significantly reduced at all different durations. The swelling tends to be Na+ > Ca2+ > Al3+ at the same saline concentration in the solution. Studies of the absorbency in various aqueous saline (NaCl) solutions also revealed that the swelling capacity decreased as the ionic strength of the swelling medium rose, which is consistent with the experimental results and Flory's equation. Furthermore, the experimental results strongly suggested that second-order kinetics governs the swelling process of the hydrogel in various swelling media. The swelling characteristics and equilibrium water contents for the hydrogel in various swelling media have also been researched. The hydrogel samples have been successfully characterized by FTIR to show the change in chemical environment to COO- and CONH2 groups after swelling in different swelling media. The samples have also been characterized by SEM technique.

Influence of air plasma modification power on surface properties of basalt fibers and basalt/poly(butylene succinate) adhesion

In this study, basalt fibers were treated with air glow discharge plasma at the powers of 50, 100, 200, and 300 W to investigate the influence of plasma power on fiber surface treatment and basalt/poly(butylene succinate) (PBS) adhesion. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) images showed rougher fiber surfaces when the plasma power was higher than 50 W. Water absorption measurement results demonstrated that the wettability of plasma-treated groups was significantly improved. X-ray photoelectron spectroscopy (XPS) showed that the atomic ratio of O/C increased to 0.91, 1.05, 1.86, and 1.86 for the 50 W, 100 W, 200 W, and 300 W groups, respectively. Tensile testing results of single fibers showed no strength reduction after modification. Microbond pull-out test revealed an increase in the interfacial adhesion of up to 39.2 % between basalt fiber and PBS for the 300 W group. This study demonstrates that our air plasma treatment technique was effective in the modification process for improving the basalt/PBS interfacial adhesion, where the selection of appropriate plasma treatment power was critical.

Study on Mechanical and Durability Characteristics of Sustainable Geopolymer Concrete

Abstract: The concentration of greenhouse gases in the atmosphere has increased quickly as a result of anthropogenic activities that cause global warming. To solve this issue, Portland cement-free geopolymer concrete is created by using ground granulated blast furnace slag (GGBS) as the primary binder and micronized biomass silica (MBS) in varying proportions in composition of GGBS. The outcomes of this experimental investigation demonstrate the mechanical properties and robustness of geopolymer concrete. In the creation of MBS, rice husk is utilized. Besides from compression, flexural, split tensile strength, and elastic modulus testing, further measurements of water absorption, water sorptivity and rapid chloride permeability test were also carried out. It is found that a geopolymer concrete mix with 10% MBS and 90% GGBS as a binder had the best strength and durability. Also, the compressive strengths of each geopolymer concrete mixture exceeded the required design strength. This experimental investigation shows the possibility of employing MBS as a binder raw material in the production of geopolymer concrete.

Structuring multiscale porous architecture in polyether sulfone films for ultra-low dielectric constant

Ultra-low dielectric constant materials possess a broad prospect for application in microelectronics devices and communication systems. The most efficient method for fabricating low dielectric constant materials is the incorporation of porous structure into the materials. However, it is vital and remains a great challenge to precisely control the size, distribution and number of pore structures for porous films to maintain comprehensive properties. Herein, a series of novel multiscale porous polyether sulfone-polyhedral oligomeric silsesquioxanes (PES-POSS) films with ultra-low dielectric constants were fabricated by solvent phase inversion approach. Specifically, the prepared PES-60%POSS (P60) films demonstrate an ultra-low dielectric constant and dielectric loss of 1.31 and 0.00078 at 1 kHz. Multiscale pores ranging from micron to nano and low molar polarization of POSS nano-hybrids are the key to its low dielectric properties of the resultant materials. Moreover, the interface enhancement by the covalent bonding of POSS and PES skeleton ensures that the composite hybrid films maintain reliable thermal and mechanical properties while possess low dielectric properties. The measurements of contact angle and water absorption show the PES-POSS films have favorable water resistance. That is beneficial to the dielectric stability and service life of films. In addition, the average transmissivity coefficient of P60 films in X-band is high up to 95.6%, which show the potential of application as an excellent wave transmitting material.

Water absorption in hollow glass microsphere composites under hydrostatic pressure: Mechanisms and influencing parameters

AbstractHollow glass microsphere composites, or syntactic foams, are widely used in marine environments due to their buoyancy. However, in service, loss of buoyancy occurs along time. This behavior is attributed to water absorption that leads to a mass increase of the material. This study investigates the water absorption of three types of syntactic foams under hydrostatic pressure with density ranging from 0.59 to 0.74 g. cm−3. Water absorption measurements are performed for a maximal duration of 3 years and under hydrostatic pressure up to 700 bars. Results show that water absorption is much higher than expected and attributed to the filling of microspheres that collapse over time. Based on results presented here, prediction of water absorption syntactic foams is proposed including the impact of applied hydrostatic pressure. This prediction allows estimating the buoyancy loss in hollow glass microsphere composite as a function of time, depth and sample size.

Stable isotopes δ18O and δ2H reveal differential water uptake from intercropped maize and soybean soil profiles

The objective of this study was to investigate the effect of different intercropping modes on grain yield, crop water uptake, and water use efficiency in the rainfed agricultural regions. Conventional research methods had difficulties in accurately measuring water absorption soil profiles of grain crops under intercropping system. In this study, the seasonal variations in water uptake patterns of maize and soybean were identified using stable isotopes δ 18 O and δ 2 H in plant and soil water coupled with IsoSource model in monocrop and three intercropping modes: M2S2 (2 rows of maize and 2 rows of soybean), M2S4 (2 rows of maize and 4 rows of soybean), and M4S2 (4 rows of maize and 2 rows of soybean) on the Loess Plateau, China. The dominant water uptake depth of maize under monocrop contributed to 61.8 ± 10.3% in 0–20 cm, 40.3 ± 3.4% in 150–200 cm, and 65.3 ± 11.6% in 20–70 cm soil profiles of the total water uptake at the jointing, silking, and maturity stages, respectively. The dominant water uptake depth of intercropped maize contribute to 46.1 ± 1.1% in 0–20 cm, 31.8 ± 0.8% in 70–150 cm, and 36.9 ± 2.1% in 150–200 cm soil profiles of the total water uptake at the jointing, silking, and maturity stages, respectively. For soybean, the soil water at the 0–20 cm depth contributed 73.0 ± 2.4% (monocrop) and 78.4 ± 6.2% (intercrops) of the total water uptake across all three growth stages, respectively. Land equivalent ratio greater than one indicates yield advantages in intercropping systems compared to monocrop. Intercropped maize absorbed water from the soil layer deeper than that of soybean during the middle to late growth stages, indicating the intercropping advantages due to the differential water absorption depth. M4S2 mode had shallower main water absorption depth and higher water use efficiency than M2S2 and M2S4, respectively. The present study identified differential water absorption patterns between maize and soybean. The M4S2 intercrop mode was considered the optimal mode for rainfed intercropping systems due to its greater land and water use efficiency on the Loess Plateau. • Stable isotopes δ 18 O and δ 2 H reveal root-zone water dynamics in intercropping. • The soybean mainly used soil water from 0 to 20 cm under all cropping modes. • Maize had deeper main water absorption than soybean when intercropped. • The water absorption depth of maize increased over the growth period in intercropping.

Highlighting Bacteria with Calcifying Abilities Suitable to Improve Mortar Properties.

Biomineralization, the use of microorganisms to produce calcium carbonate, became a green solution for application in construction materials to improve their strength and durability. The calcifying abilities of several bacteria were investigated by culturing on a medium with urea and calcium ions. The characterization of the precipitates from bacterial cultures was performed using X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The formation of carbonate crystals was demonstrated by optical and scanning electron microscopy. Water absorption and compressive strength measurements were applied to mortars embedded with sporal suspension. The efficiency of the supplementation of mortar mixtures with bacterial cells was evaluated by properties, namely the compressive strength and the water absorption, which are in a relationship of direct dependence, the increase in compressive strength implying the decrease in water absorption. The results showed that Bacillus subtilis was the best-performing bacterium, its introduction into the mortar producing an increase in compressive strength by 11.81% and 9.50%, and a decrease in water absorption by 11.79% and 10.94%, after 28 and 56 days of curing, respectively, as compared to standards. The exploitation of B. subtilis as a calcifying agent can be an interesting prospect in construction materials.

Lithium Orthosilicate-Linear Low-Density Polyethylene Nano-Composite as Substrate for High Frequency Devices: Dielectric Characterization

Dielectric properties of nanosized Lithium Orthosilicate (Li 4 SiO 4 ) and linear low-density polyethylene composite at X-Band frequencies are investigated, to realize its utility as a substrate for microwave devices. Solid state technique is used to synthesize nano Li 4 SiO 4 . To confirm the structural and morphological properties of the synthesized nano Li 4 SiO 4 , X-ray diffraction, Fourier transformed infrared spectroscopy and transmission electron microscopy are used. Composites of nano Li 4 SiO 4 and linear low-density polyethylene matrix are synthesized with varying weight fraction of nano Li 4 SiO 4 viz. 2%, 4% and 6%. The lateral portion of a fractured sample (composite) is examined using scanning electron microscope to confirm homogeneous dispersion of nano Li 4 SiO 4 in linear low-density polyethylene matrix. Water absorption measurement of all the composites are carried out based on ASTM D570-98 . Densities of the composites are measured via hydrostatic weighing by using Archimedes principle. Complex permittivity and permeability measurement of the composites are recorded by utilizing Nicholson-Ross approach. For all weight fraction of the nano inclusions, the real component of permittivity and dielectric loss tangent of the composites in the X-band are found to be in the range of 2.2 – 2.6 and 10 -2 –10 -4 , respectively. Return losses for the composites are calculated from complex permittivity and permeability values to validate its applicability as substrate for various high frequency applications.

Experimental Investigation of a New Design of Insulation Gypsum Plaster Blocks

Green building materials are an alternative to ordinary materialsoffering multiple environmental benefits. This study consists of an experimental investigation of a new design of gypsum plaster blocks. First, a mix design of gypsum plaster and water mixture was prepared. The optimal mix composition was determined according to the mechanical and physical properties, such as the water absorption, the temperature of hydration, the density, and the compressive strength of different gypsum plaster and water mixtures made by varying the water dosage. The second part of this investigation aims to study a new design of green blocks prepared from the optimal water and gypsum plaster mixture. The new blocks are perforated to lighten them and to reduce their thermal conductivity in order to make them moreinsulate. Experimental tests were conducted on the block prototype, such as the measurement of dimensional tolerances, compressive strength, density, flatness, water absorption, residual moisture, surface hardness, and thermal conductivity. Experimental test results show that the new blocks have very low density, and their compressive strength is sufficient for wall construction. In addition, the manufacturing process of the new blocks is very easy and very fast. Finally, the obtained physical and mechanical properties of the new gypsum plaster blocks give it the opportunity to be used for interior walls for building constructions.

Measurement of Water Absorption of Recycled Aggregate.

Owing to the high absorption capacity of recycled aggregate (RA), it is crucial to accurately measure its saturated-surface-dried water absorption (WSSD), which largely affects an effective water-to-binder ratio of recycled aggregate concrete. In this study, existing measurement methods for the WSSD of RA are extensively reviewed, including Wiping, Slumping, Centrifugation, Infrared, Evaporation, Airflow drying, Conductivity, Pycnometer, Hydrostatic balance, and Extrapolation. In particular, the physical principles and operability of these methods are emphasized. It was determined that the accuracy of all test results was not satisfactory. For example, the water in pores with an open-ended direction that was opposite to the centrifugal force could largely be retained. In Airflow drying, the temperature change was significantly delayed. In addition, in Hydrostatic balance, RA would pre-absorb water before determining the initial reading. Therefore, several suggestions for optimizing these methods are presented, such as the combination of Evaporation and Airflow drying, the liquid selection in Hydrostatic balance, and the addition of a tiny mixer in each centrifuge tube. In summary, this review facilitates the development of an accurate and convenient method for measuring the WSSD of RA.

Use of Bacteria to Activate Ground-Granulated Blast-Furnace Slag (GGBFS) as Cementless Binder.

Ground-granulated blast-furnace slag (GGBFS) can be used as a cementless binder after activation. Recent approaches to activate GGBFS have focused on chemical methods that use NaOH, KOH, and CaO. This study introduces the use of bacteria to activate GGBFS as a biological approach. The presence of bacteria (volumetric ratio), curing temperature (23 °C and 60 °C), and number of curing days (3, 7, and 28 d) are investigated. The use of urea is considered owing to the possibility of calcium carbonate formation. The activated GGBFS is evaluated in the form of a cube (5 cm × 5 cm × 5 cm) for its strength, mineral identification, and pore size distribution. A brick (19 cm × 9 cm × 5.7 cm) is prefabricated to see the feasibility of commercializing bacteria-activated GGBFS based on water absorption and strength measurements. All results are compared with those of water-activated GGBFS. The results indicate that the use of urea inhibits the strength improvement of bacteria-activated GGBFS. Bacterial suspension enhances the GGBFS strength at a curing temperature of 60 °C. Mineral identification tests show that the strength increase is primarily due to the formation of calcite. The compressive strength satisfies the commercial standard of concrete bricks; however, the water absorption rate must be resolved.

Three-phases bubble column to polyethylene terephthalate depolymerization for cement mortar composites improvement

This paper aims to prepare depolymerized polyethylene terephthalate (DPET) powder from recycled plastic water bottles. Adding this DPET powder to the cement mortar was also studied. The adopted PET depolymerization process includes the usage of both ethylene glycol (EG) as solvent and nano-MgO as a catalyst. A bubble column reactor was designed for this process. Five different mortar groups were made; each has different DPET content of 0%, 1%, 3%, 6% and 9% as a sand replacement. The flexural strength test and the water absorption measurement are done after two curing periods: 7 and 28 days. The research finding demonstrated that the flexural strength of mortar was reduced by increasing the DPET powder percentage and the maximum dropping was 15% when 9% of DPET was added. The ability of the mortar to absorb the water was reduced by 14.5% when DPET powder was 9%. The mortar microstructure is featured with fewer cavities and porosity. This work’s employed bubble column technique is limited only to the laboratory environment and needs to be scaled up within industrial mass production. For future research, it is suggested to decrease depolymerization time by using smaller pieces of plastic water bottle waste and trying other types of nanocatalyst. The modified mortar can be utilized in areas where moisture, rainfalls, and sanitation systems exist. The article claims that depolymerized waste PET improves chemical process efficiency by lowering reaction time and improving mass and heat transfer rates. Besides, this approach saves money. It is found out that the depolymerized plastic waste is much more functional due to its high cohesion capability than being used as small PET pieces.

Sulfur concrete made with waste marble and slag powders: 100% recycled and waterless concrete.

In this research, the mechanical properties and durability of sulfur concrete with two different waste aggregates were evaluated. The waste aggregates included ground granulated blast-furnace slag and waste marble powder. The properties of sulfur concrete were also compared with those of the conventional binder concretes (i.e., Portland cement concrete and sulfate-resistant cement concrete). The durability parameters included measuring water absorption capacity and resistance to different harsh chemical environments (5% HCl solution, 5 Molar NaOH solution, and 16% NaCl solution). It was found that sulfur concrete made with slag as aggregate exhibited the maximum strength, i.e., about 2 times higher than that of Portland cement concrete and sulfate-resistant cement concrete. Sulfur concrete made with slag and marble waste powder showed superior mechanical performance compared to that made with river sand. Thus, sulfur binder develops more favorable properties with eco-friendly fillers than it develops with natural sand. In harsh chloride and acidic environment, sulfur concrete with slag powder exhibited about 90-95% lesser mass loss than Portland cement concrete.

Review of net water uptake in the management of acute ischemic stroke.

CT densitometry-based methods to directly quantify net water uptake in ischemic brain tissue have been increasingly applied recently. There is potential for net water uptake to be used as an imaging biomarker for the pathophysiology of infarcted lesions. This review is aimed at summarizing the potential and current status of the application of net water uptake as a biomarker in the management of ischemic stroke and future directions in this context. Specifically, we provide a brief overview of the principle and different methods of net water uptake measurement, followed by a discussion of the role of net water uptake in predicting malignant brain edema and hemorrhagic transformation, evaluating lesion age, and predicting the efficacy of reperfusion therapy and long-term clinical prognosis. Artificial intelligence will help address the lack of automation and standardization in the measurement of net water absorption. Further validation of net water uptake in a prospective multicenter setting is necessary. KEY POINTS: • NWU can be used as a quantitative imaging biomarker for developing malignant brain edema in anterior and posterior circulation strokes. • The difference in NWU in edema arrest or reversibility suggests that rapid and successful revascularization can influence the progression of ischemic edema. • NWU can be used to predict the age of a lesion, with predictive power comparable to that of DWI/FLAIR mismatch.

Experimental evaluation of using pyrolyzed carbon black derived from waste tires as additive towards sustainable concrete

Waste tires (WTs) are one of the most critical environmental problems worldwide. Since the WTs cannot be landfilled or burned, innovative solutions and proper solid waste management are needed. Therefore, several methods have been proposed for WTs treatment. Among these methods, the pyrolysis process is considered the most favorable. Pyrolysis is a process of converting WTs in absence of oxygen into pyrogas, fuel oil, and a by-product, which is pyrolyzed carbon black (PCB). To introduce the idea of eco-friendly and sustainable concrete, it is proposed to use PCB as an additive in concrete structures. In this experimental investigation, PCB samples are obtained from a local pyrolyzed WTs plant. Several concrete properties are investigated considering different mixes of different weight percentage ratios of PCB to cement (PCB/c); 0% (control sample), 3%, 3.5%, 4%, 4.5%, 5%, 7%, and 10%. Typically, fixed amounts of cement, water, sand, aggregate, and superplasticizer are prepared following international preparation standards, and then, mixed with the aforementioned PCB/c ratios. Afterward, an array of mechanical tests are performed investigating properties enhancements. These tests are slump, compressive strength, and abrasion resistance, along with water absorption. Results show a noticeable increase in the compressive strength for tested samples of 29.3 and 38.4 MPa were obtained at a ratio of 4% for 7 and 28 days, respectively. This is combined with a slight reduction of slump results; however; slump values are still within standard limits for most of the mixes. In addition, abrasion resistance results suggest a vital improvement in the PCB/c mixes. Also, water absorption measurements reflect enhancement of concrete mixes up to a specific percentage of PCB. Amongst tested PCB/c ratios, the study highlights the optimal value to be between 3% and 5%. In addition, a multi-level framework on the impact of institutional pressures on the adoption of PCB as an additive to cement has been addressed to rationalize and raise awareness towards the applicability of such a feasible approach. Thus, the overall results reflect the promising horizons of using PCB as an improving additive material in concrete mixes.

ASSESSMENT OF THE EFFECT OF MODIFIED ADDITIVES ON THE HOMOGENEITY OF AERATED CONCRETE BY LABORATORY TESTS

The article presents the results of the research of impregnation composition for concrete roads, which allows to improve the ice-phobic properties of the coating. The impregnating composition is based on keratin-containing components and water-soluble polymer. Studies of qualitative indicators of the composition were carried out in laboratory conditions: determination of the optimal water concentrate of impregnation composition was made by measuring water absorption capacity of samples, and the assessment of durability (wear resistance to mechanical impacts or percentage of abrasion) was carried out by model tests with wheel loadings.