23 research outputs found
Anion Effect on Forward Osmosis Performance of Tetrabutylphosphonium-Based Draw Solute Having a Lower Critical Solution Temperature
The applicability of ionic liquids (ILs) as the draw solute in a forward osmosis (FO) system was investigated through a study on the effect of the structural change of the anion on the FO performance. This study evaluated ILs composed of tetrabutylphosphonium cation ([P4444]+) and benzenesulfonate anion ([BS]−), para-position alkyl-substituted benzenesulfonate anions (p-methylbenzenesulfonate ([MBS]−) and p-ethylbenzenesulfonate ([EBS−]), and methanesulfonate anion ([MS]−). The analysis of the thermo-responsive properties suggested that the [P4444][MBS] and [P4444][EBS] ILs have lower critical solution temperatures (LCSTs), which play a beneficial role in terms of the reusability of the draw solute from the diluted draw solutions after the water permeation process. At 20 wt% of an aqueous solution, the LCSTs of [P4444][MBS] and [P4444][EBS] were approximately 36 °C and 25 °C, respectively. The water flux and reverse solute flux of the [P4444][MBS] aqueous solution with higher osmolality than [P4444][EBS] were 7.36 LMH and 5.89 gMH in the active-layer facing the draw solution (AL-DS) mode at osmotic pressure of 25 atm (20 wt% solution), respectively. These results indicate that the [P4444]+-based ionic structured materials with LCST are practically advantageous for application as draw solutes
Anion Effect on Forward Osmosis Performance of Tetrabutylphosphonium-Based Draw Solute Having a Lower Critical Solution Temperature
The applicability of ionic liquids (ILs) as the draw solute in a forward osmosis (FO) system was investigated through a study on the effect of the structural change of the anion on the FO performance. This study evaluated ILs composed of tetrabutylphosphonium cation ([P4444]+) and benzenesulfonate anion ([BS]−), para-position alkyl-substituted benzenesulfonate anions (p-methylbenzenesulfonate ([MBS]−) and p-ethylbenzenesulfonate ([EBS−]), and methanesulfonate anion ([MS]−). The analysis of the thermo-responsive properties suggested that the [P4444][MBS] and [P4444][EBS] ILs have lower critical solution temperatures (LCSTs), which play a beneficial role in terms of the reusability of the draw solute from the diluted draw solutions after the water permeation process. At 20 wt% of an aqueous solution, the LCSTs of [P4444][MBS] and [P4444][EBS] were approximately 36 °C and 25 °C, respectively. The water flux and reverse solute flux of the [P4444][MBS] aqueous solution with higher osmolality than [P4444][EBS] were 7.36 LMH and 5.89 gMH in the active-layer facing the draw solution (AL-DS) mode at osmotic pressure of 25 atm (20 wt% solution), respectively. These results indicate that the [P4444]+-based ionic structured materials with LCST are practically advantageous for application as draw solutes
Influence of Health Behaviors and Occupational Stress on Prediabetic State among Male Office Workers
This study examined the influence of health behaviors and occupational stress on the prediabetic state of male office workers, and identified related risks and influencing factors. The study used a cross-sectional design and performed an integrative analysis on data from regular health checkups, health questionnaires, and a health behavior-related survey of employees of a company, using Spearman’s correlation coefficients and multiple logistic regression analysis. The results showed significant relationships of prediabetic state with health behaviors and occupational stress. Among health behaviors, a diet without vegetables and fruits (Odds Ratio (OR) = 3.74, 95% Confidence Interval (CI) = 1.93–7.66) was associated with a high risk of prediabetic state. In the subscales on occupational stress, organizational system in the 4th quartile (OR = 4.83, 95% CI = 2.40–9.70) was significantly associated with an increased likelihood of prediabetic state. To identify influencing factors of prediabetic state, the multiple logistic regression was performed using regression models. The results showed that dietary habits (β = 1.20, p = 0.002), total occupational stress score (β = 1.33, p = 0.024), and organizational system (β = 1.13, p = 0.009) were significant influencing factors. The present findings indicate that active interventions are needed at workplace for the systematic and comprehensive management of health behaviors and occupational stress that influence prediabetic state of office workers
Vertical Alignment of Liquid Crystals on Comb-Like Renewable Chavicol-Modified Polystyrene
This study demonstrates liquid crystal (LC) alignment behaviors on the surface of phytochemical-based and renewable chavicol-modified polystyrene (PCHA#, # = 20, 40, 60, 80, and 100, where # represent the molar content of chavicol moiety in the side group) via polymer modification reactions. Generally, a LC cell fabricated with a polymer film containing a high molar content of the chavicol side group exhibited a vertical LC alignment property. There is a correlation between the vertical alignment of LC molecules and the polar surface energy value of the polymer films. Therefore, vertical LC alignment was observed when the polar surface energy values of these polymer films were smaller than about 1.3 mJ/m2, induced by the nonpolar chavicol moiety having long and bulky carbon groups. Aligning stability under harsh conditions such as ultraviolet (UV) irradiation of about 5 J/cm2 was observed in the LC cells fabricated from PCHA100 film. Therefore, it was found that the plant-based chavicol-substituted polymer system can produce an eco-friendly and sustainable LC alignment layer for next-generation applications
Vertical Alignment of Liquid Crystals on Phenylphenoxymethyl-Substituted Polystyrene—PS Derivatives Structurally Similar to LC Molecules
A series of polystyrene derivatives containing precursors of liquid crystal (LC) molecules, phenylphenoxymethyl-substituted polystyrene (PPHE#; # = 5, 15, 25, 50, 75, and 100)—where # is the molar content of 4-phenylphenol using polymer modification reactions—were prepared in order to examine the effect of the polymer film, which possess similar LC molecular structure on the LC alignment properties. It was found that the Tg values of the PPHE# were higher than 100 °C due to their aromatic structure in the biphenyl-based PHE moiety. The LC cells fabricated with PPHE5 and PPHE15 films exhibited planar LC alignment. Conversely, LC molecules showed a vertical alignment in LC cells made using the polymer films with phenylphenoxymethyl side groups in the range of 25–100 mol %. The polar surface energies on the PPHE# films can be associated with the vertical LC alignment on the PPHE# films. For example, vertical LC alignment was exhibited when the polar surface energy of the polymer films was less than approximately 4.2 mJ/m2. Aligning stability was observed at 200 °C and UV irradiation of 20 J/cm2 for LC cells made using the PPHE100 film. Therefore, it was found that biphenyl, one of the LC precursors, modified polystyrene derivatives and can produce a next-generation vertical LC alignment system
Laboratory Evaluation of Storage Stability for CRM Asphalt Binders
This paper conveys the laboratory investigation of the storage stability of CRM binder as a basic study. The CRM binder was produced through the wet process in the laboratory. The percentages of crumb rubber used for rubberized binder were 5%, 10%, 15% and 20%. The samples were prepared according to ASTM D7173. In order to evaluate the properties of each part of the binders, tests were carried out through the rotational viscosity and viscoelasticity, and the separation index was assessed with the G*/sin δ and %rec. In general, the results of this study revealed that (1) the conditioned CRM binders appeared to have higher viscosity in the bottom part compared to the middle and top parts.; (2) similar to the viscosity results, the CRM binders after conditioning showed the highest G*/sin δ value in the bottom part; (3) from the MSCR test, Jnr and % rec values are observed to have a similar trend with G*/sin δ results, although some of the data were not measured due to the higher load than the DSR test; and (4) it was discovered that the SI from G*/sin δ generally used was suitable for evaluating the storage stability of CRM asphalt binders, compared to the SI from % rec
Laboratory Evaluation of Storage Stability for CRM Asphalt Binders
This paper conveys the laboratory investigation of the storage stability of CRM binder as a basic study. The CRM binder was produced through the wet process in the laboratory. The percentages of crumb rubber used for rubberized binder were 5%, 10%, 15% and 20%. The samples were prepared according to ASTM D7173. In order to evaluate the properties of each part of the binders, tests were carried out through the rotational viscosity and viscoelasticity, and the separation index was assessed with the G*/sin δ and %rec. In general, the results of this study revealed that (1) the conditioned CRM binders appeared to have higher viscosity in the bottom part compared to the middle and top parts.; (2) similar to the viscosity results, the CRM binders after conditioning showed the highest G*/sin δ value in the bottom part; (3) from the MSCR test, Jnr and % rec values are observed to have a similar trend with G*/sin δ results, although some of the data were not measured due to the higher load than the DSR test; and (4) it was discovered that the SI from G*/sin δ generally used was suitable for evaluating the storage stability of CRM asphalt binders, compared to the SI from % rec
Characterization of Sustainable Asphalt Binders Modified with Styrene–Isoprene–Styrene (SIS) and Processed Oil
The current study aims to evaluate the viscosity and rheological properties of PG 64-22 modified with Styrene–Isoprene–Styrene (SIS) and Processed Oil (PO) to enhance asphalt binder properties. Performance properties were measured at high, intermediate, and low temperatures. PG 64-22 was blended with SIS and Processed Oil at three levels (5%, 10%, and 15% by weight of binder) and two concentrations (6% and 12% by weight of binder), respectively. Modified binders underwent two short and long artificial aging processes, through the spinning of the thin film in an RTFO oven and a pressure aging vessel (PAV). The Superpave binder evaluations were carried out using a rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). According to the findings of the research, the addition of SIS caused higher values of viscosity, but when co-modified with processed oil, there was a substantial decrease in viscosity values. As a result, workability was improved. (1) It was observed that a greater reduction in viscosity was achieved when the processed oil was present at a higher concentration at 135 °C compared to a lower concentration. (2) The study showed that the incorporation of processed oil led to a reduction in rutting performance of the asphalt binder. However, the addition of SIS resulted in a notable enhancement of rutting resistance. (3) The role of processed oil as co-modifier at concentrations of 6% and 12% caused significant decreases in G*sin δ, based on the susceptibility of asphalt molecules to accept oil molecules in their network links. (4) The extracted measurements from the BBR tests indicated that modification with SIS and PO improved the low-temperature cracking resistance significantly. Comparison of asphalt binders modified with 6% and 12% PO and the same SIS content showed significant changes in modification with 12% PO rather than 6%