Hydrophobizing polyether sulfone membrane by sol-gel for water desalination using air gap membrane distillation

ABSTRACT

The hydrophobic polyether sulfone membranes were prepared by the sol-gel method to be applied in an air gap membrane distillation setup for desalination. The surface modifications were carried out using Trimethylsilyl chloride (TMSCl) and Methyltrimethoxysilane (MTMS) solutions. The membranes were characterized using Attenuated Total Reflection Infrared (ATR-IR) spectroscopy, Scanning Electron Microscopy (SEM), and Optical Contact Angle (OCA) methods. The effects of membrane preparation as well as operating conditions such as temperature difference, salt concentration, feed rotation speed, and cold-side temperature on membrane performance were investigated using central composite design method. It was found that feed temperature has the largest effect among the parameters on the permeation flux. The flow rate and salt rejection of the membrane in the optimum conditions were 4.47 Kg m^?2 h^?1 and 99.37%, respectively.     

Genetic and genomic analysis of age at first insemination in Israeli dairy cattle

We performed a genetic analysis of age at first insemination, including estimation of the heritability and genetic correlations with other economic traits, and the consequences of including this trait in the Israeli selection index. The genetic factors affecting age at first insemination were determined via GWAS. Five data sets were analyzed. Data sets 1, 2, and 3 were used to compute variance components among age at first insemination, first calving age, days from first insemination to calving, and the 9 traits included in the Israel breeding index. Heritabilities for age at first insemination, calving age, and days from first insemination to calving in Israeli Holsteins as computed by REML individual animal model analyses of 273,239 Israeli Holstein cows were 0.072, 0.042, and 0.014. The estimated genetic correlation between the first 2 traits was 0.88. In addition to the fact that heritability of age at first insemination is 1.7 times the heritability for calving, the former trait has the advantage that the number of records is greater, and the records are generated earlier. Absolute values of the genetic and residual correlations between age at first insemination and the 9 traits included in the Israeli index were all less than 0.2. Data set 4 included first insemination dates of 1,181,600 calves born from 1985 through 2018. Genetic evaluations were computed by a single trait animal model. Annual phenotypic and genetic trends for age at first calving for calves born since 1985 were “positive,” that is, economically negative, at 0.320 ± 0.003 and 0.169 ± 0.005 d, respectively. Applying the GCTA-GREML software, 54% of variance in the transmitting ability of 1,585 sires could be explained by considering all 40,498 markers included in the GWAS analysis. The significant markers were mainly associated with milk production genes. The SNP UA-IFASA-8854 on chromosome 11 had the lowest probability value, 1.2 × 10^?24. This marker is located between the genes RETSAT and ELMOD3, both of which are overexpressed in human mammary glands. The gene RETSAT is reported to be essential for lipid accumulation and adipogenesis promotion. Gene enrichment analysis found that genes in the genomic region flanking significant markers are associated with vasopressin receptor activity, which was shown to mediate puberty in humans. If age at first insemination is included in the index with a weighting to account for 9% of the index, reductions of 2.8 and 2.6 d for age at first insemination and first calving age after 10 yr of selection are predicted, as compared with reductions of 1.4 and 1.1 d with the current index. Gains for the other index traits are only marginally affected. We suggest selection on age at first insemination as an alternative to selection for early calving.     

Dual pH‐ and thermal‐responsive nanocomposite hydrogels for controllable delivery of hydrophobic drug baicalein

Hydrogels have been widely used as mild biomaterials due to their bio‐affinity, high drug loading capability and controllable release profiles. However, hydrogel‐based carriers are greatly limited for the delivery of hydrophobic payloads due to the lack of hydrophobic binding sites. Herein, nano‐liposome micelles were embedded in semi‐interpenetrating poly[(N‐isopropylacrylamide)‐co‐chitosan] (PNIPAAm‐co‐CS) and poly[(N‐isopropylacrylamide)‐co‐(sodium alginate)] (PNIPAAm‐co‐SA) hydrogels which were responsive to both temperature and pH, thereby establishing tunable nanocomposite hydrogel delivery systems. Nano‐micelles formed via the self‐assembly of phospholipid could serve as the link between hydrophobic drug and hydrophilic hydrogel due to their special amphiphilic structure. The results of transmission and scanning electron microscopies and infrared spectroscopy showed that the porous hydrogels were successfully fabricated and the liposomes encapsulated with baicalein could be well contained in the network. In addition, the experimental results of response release in vitro revealed that the smart hydrogels showed different degree of sensitiveness under different pH and temperature stimuli. The results of the study demonstrate that combining PNIPAAm‐co‐SA and PNIPAAm‐co‐CS hydrogels with liposomes encapsulated with hydrophobic drugs is a feasible method for hydrophobic drug delivery and have potential application prospects in the medical field. © 2018 Society of Chemical Industry     

Improved rheological properties and stability of multiwalled carbon nanotubes/polymer in harsh environment

This work aims to improve the rheological properties and stability of multiwalled carbon nanotubes (MWCNTs)/acrylamide (AA) base skeleton polymer blends at harsh environment of high salinity-high temperature (HS-HT) or various pH. Different co/terpolymers have been accomplished to modify the structure of AA polymer by free-radical copolymerization of AA-based monomers. Anionic, cationic, and hydrophobic functional groups were used for the synthesis of polyelectrolyte, polyampholytic, and partially hydrophobic AA polymer types. The conversion, molecular weight, and poly dispersity of co/terpolymers have been evaluated by nuclear magnetic resonance (¹H-NMR), gel permeation chromatography, and differential scanning calorimetry analysis. The effects of sonication power, concentration of polymer, and concentration of MWCNTs were also investigated on rheological behavior of co/terpolymers. The results show that negative polyelectrolyte and polyampholytic polymers are the best candidates for the improvement of MWCNTs/polymer stability and viscosity at HS-HT and alkali environment, respectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47205.     

HF刻蚀工艺对AZ91D镁合金疏水膜性能的影响

为了改善AZ91D镁合金表面疏水膜的疏水性,对以HF和N^MoOq为主要成分的刻蚀液进行了研究。通过改变刻蚀温度、刻蚀时间、HF的浓度及Na2MoO4的质量浓度,确定了最佳的刻蚀工艺条件为:HF 0.10 mol/L,Na2MoO41.00 g/L,1525°C,90 so实验结果表明:使用HF刻蚀液可以在镁合金表面形成理想的微纳结构。通过刻蚀构建的微纳结构可以明显提高疏水膜的疏水性。     

氯化镧对镁合金表面疏水化处理的影响

研究了氯化镧对镁合金疏水膜耐蚀性的影响。采用中性盐雾试验和电化学试验测试了疏水膜的耐蚀性,并采用扫描电子显微镜观察了疏水膜的表面形貌。结果表明:氯化镧对镁合金疏水膜有一定的改性作用,使膜层由乳突状结构转变为层片状结构,进而使膜层由疏水表面转变为超疏水表面,其接触角可达153°。另外,添加氯化镧后疏水膜的盐雾时间延长至109.0 h,耐蚀性大幅提高。     

纳米纤维素的疏水改性及应用研究进展

纳米纤维素作为一种性能优越的可再生纳米材料，应用前景极为广阔。然而，由于纳米纤维素结构上富含羟基，使其具有极强的亲水性，严重影响了纳米纤维素的疏水性能，并且在一定程度上限制了其在复合材料领域的应用。综述了纳米纤维素疏水改性的研究进展，从物理吸附、表面化学修饰（甲硅烷化、烷酰化、酯化等）、聚合物接枝共聚3个方面简述了目前应用较为广泛的疏水化改性方法，并对疏水纳米纤维素在包装材料、造纸、水净化等方面的应用现状进行了总结。最后对疏水改性纳米纤维素的未来发展进行了展望，旨在为疏水纳米纤维素的研究和应用提供参考。     

Similarities and differences between male and female novice designers on color‐concept associations for warnings,action required,and signs and equipment status messages

This research examined the male and female novice designers toward color associations for the concepts used for ‘warnings’, ‘action required’, and ‘signs and equipment status’ through a questionnaire‐based study. A total of 178 Hong Kong Chinese final year undergraduate design students (89 males and 89 females) participated in the study. The test used required the participants to indicate their choice of one of nine colors to associations with each of 38 concepts in a color‐concept table, so that any one color could be associated with any one of the concepts. For both male and female groups of novice designers, chi‐square tests revealed a strong color association for each concept tested in this study (P < .05). The results showed males and females agreed on some color‐concept association stereotypes which were therefore gender neutral. The male and female novice designers had the same color associations and similar levels of stereotype strengths for 21 concepts. The nine strongest and therefore most useful color‐concept association stereotypes for both male and female novice designers were: red‐danger, red‐fire, red‐hot, red‐stop, red‐emergency, red‐error, blue‐cold, blue‐male, and green‐exit. However, the male and female novice designers had different color association stereotypes for the standby (green vs. yellow), emergency exit (green vs. red), and toxic (purple vs. black) concepts, and the strengths of the 14 remaining associations for both groups were not at equivalent levels. Overall, it is anticipated that the findings of this study will act as a useful reference for novice designers and other design practitioners to optimize color coding in the design of ‘warnings’, ‘action required’, and ‘signs and equipment status’ messages.     

A proposed expert system for word sense disambiguation: deductive ambiguity resolution based on data mining and forward chaining

One of the major issues in the process of machine translation is the problem of choosing the proper translation for a multi‐sense word referred to as word sense disambiguation (WSD). Two commonly used approaches to this problem are statistical and example‐based methods. In statistical methods, ambiguity resolution is mostly carried out by making use of some statistics extracted from previously translated documents or dual corpora of source and target languages. Example‐based methods follow a similar approach as they also make use of bilingual corpora. However, they perform the task of matching at run‐time (i.e. online matching). In this paper, by looking at the WSD problem from a different viewpoint, we propose a system, which consists of two main parts. The first part includes a data mining algorithm, which runs offline and extracts some useful knowledge about the co‐occurrences of the words. In this algorithm, each sentence is imagined as a transaction in Market Basket Data Analysis problem, and the words included in a sentence play the role of purchased items. The second part of the system is an expert system whose knowledge base consists of the set of association rules generated by the first part. Moreover, in order to deduce the correct senses of the words, we introduce an efficient algorithm based on forward chaining in order to be used in the inference engine of the proposed expert system. The encouraging performance of the system in terms of precision and recall as well as its efficiency will be analysed and discussed through a set of experiments.     

Polymers dynamics of the nonfluoro,nano-brush repelling agent with self-stratifying property in water-based coatings

While perfluoroalkyl acids (PFAAs), also known as C8s, are used extensively in textile repellent coatings, concerns have arisen for their carcinogenicity and hazardous effects on the environment. In this study, a novel water-based, nonfluoro, and nanobrush textile repelling agent was prepared by conventional sol–gel chemistry using amorphous fumed silica and n-octyltriethoxysilane as the starting materials. Minimal interaction between the designed repelling agent and marketed water-based resins was confirmed using linear viscosity region (LVR) analysis and asymmetric-flow field-flow fractionation (AF4), suggesting the self-stratification potential of the repelling agent. More specifically, the repelling agent exhibited excellent compatibility and self-stratifying ability with a force-emulsified acrylic-based resin, affording a water contact angle of 104.3° when incorporated at 7% solid content. Performance tests carried out on thermoplastic polyurethane (TPU) revealed excellent adhesion (100/100) of a final formulation, and a significant increase in water contact angle from 80.1° to 103.8° after treatment. In addition, the fouling area after the removal of a submerged sample from a mixture of slurry, polymer, and oil decreased from 48 to 1% when the repelling agent was added. Moreover, the sludge-fouling property remained unchanged after 1000 cycles of abrasion. These findings demonstrate the potential of the described nonfluoro, nanobrush repelling agent as an environmentally safe alternative for use with commercial resins, in turn realizing a fully water-based hydrophobic coating. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48003.