Preparation Polyelectrolyte Complexes of Chitosan-Polyacrylic Acid-Modified Iron Sand Leachate for Proton Exchange Membranes

ABSTRACT

Polyelectrolyte complex (PEC) of chitosan (Chi) and poly (acrylic acid) (PAA)-modified iron sand leachate were prepared and considered for applicability as a proton exchange membrane in fuel cells. Chi-PAA-hematite blended in different weight ratios and the resulting membranes were treated to enable the formation of the polyelectrolyte. The membranes of Chi-PAA polyblend were treated using iron sand leachate and reveal high ion exchange capacity (IEC), proton conductivity, water uptake, and good mechanical stability. The result of research indicated that the membrane with 40 wt% of Chi and 60 wt% of PAA blend which its conductivity of 6.10 × 10^?2 S cm^?1 was potentially for a proton exchange membrane in fuel cell applications.     

The simultaneous neutron and photon interrogation method for fissile and non-fissile element separation in radioactive waste drums

Measuring -emitters such as (^{234,235,236,238}U, ^{238,239,240,242,244}Pu, ²³⁷Np, ^241,243Am, …), in solid radioactive waste allows us to quantify the -activity in a drum and then to classify it. The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method dealt with in this paper, combines both active neutron interrogation and induced photofission interrogation techniques simultaneously. Its purpose is to quantify fissile (²³⁵U, ^239,241Pu, …) and non-fissile (^236,238U, ^238,240Pu, …) elements separately in only one measurement. This paper presents the principle of the method, the experimental setup, and the first experimental results obtained using the DGA/ETCA Linac and MiniLinatron pulsed linear electron accelerators located at Arcueil, France. First studies were carried out with U and Pu bare samples.     

Some economical comparisons between aluminium and copper squirrelcages

Serious thought is being given to the use of die cast copper cages; this is why the cost of copper for cage manufacture might become reasonable, even for small motors. Eight optimum designs are presented; two different powers, two different objective functions (initial price or total price including the price of future losses), and two cage materials (copper and aluminium) have been considered. Various components of prices are compared     

Assessment of CpTi Surface Properties after Nitrogen Ion Implantation with Various Doses and Energies

Nitrogen ion implantation is one of the surface modification techniques used for increasing corrosion resistance of commercially pure titanium (CpTi). The nitrogen ion implanted CpTi in various doses markedly changes the corrosion resistance. Still the effect of nitrogen ion implantation on the CpTi at different energies needs to be verified. This study uses different methods to assess the CpTi surface properties after nitrogen ion implantation in various doses and energy. Surface hardness of the CpTi increases with an increase of the dose and decreases with an increase of the energy. The precipitation of the TiN increases with an increase of the nitrogen dose, and no formation of the Ti₂N phase clearly appears. Corrosion resistance of the CpTi specimens can be upgraded to some extent after their surfaces are modified, implanting nitrogen ions at 100?keV by increasing dose. The optimum surface properties of the implanted CpTi are analyzed to contribute to materials science technology.     

On the solutions of the rational covariance extension problem corresponding to pseudopolynomials having boundary zeros

In this note, we study the rational covariance extension problem with degree bound when the chosen pseudopolynomial of degree at most n has zeros on the boundary of the unit circle and derive some new theoretical results for this special case. In particular, a necessary and sufficient condition for a solution to be bounded (i.e., has no poles on the unit circle) is established. Our approach is based on convex optimization, similar in spirit to the recent development of a theory of generalized interpolation with a complexity constraint. However, the two treatments do not proceed in the same way and there are important differences between them which we discuss herein. An implication of our results is that bounded solutions can be computed via methods that have been developed for pseudopolynomials which are free of zeros on the boundary, extending the utility of those methods. Numerical examples are provided for illustration.     

Combining selected immunomodulatory Propionibacterium freudenreichii and Lactobacillus delbrueckii strains: Reverse engineering development of an anti‐inflammatory cheese

Scope : Inflammatory bowel disease (IBD) constitutes a growing public health concern in western countries. Bacteria with anti‐inflammatory properties are lacking in the dysbiosis accompanying IBD. Selected strains of probiotic bacteria with anti‐inflammatory properties accordingly alleviate symptoms and enhance treatment of ulcerative colitis in clinical trials. Such properties are also found in selected strains of dairy starters such as Propionibacterium freudenreichii and Lactobacillus delbrueckii (Ld). We thus investigated the possibility to develop a fermented dairy product, combining both starter and probiotic abilities of both lactic acid and propionic acid bacteria, designed to extend remissions in IBD patients. Methods and results : We developed a single‐strain Ld‐fermented milk and a two‐strain P. freudenreichii and Ld‐fermented experimental pressed cheese using strains previously selected for their anti‐inflammatory properties. Consumption of these experimental fermented dairy products protected mice against trinitrobenzenesulfonic acid induced colitis, alleviating severity of symptoms, modulating local and systemic inflammation, as well as colonic oxidative stress and epithelial cell damages. As a control, the corresponding sterile dairy matrix failed to afford such protection. Conclusion : This work reveals the probiotic potential of this bacterial mixture, in the context of fermented dairy products. It opens new perspectives for the reverse engineering development of anti‐inflammatory fermented foods designed for target populations with IBD, and has provided evidences leading to an ongoing pilot clinical study in ulcerative colitis patients.     

Biocidal polymers active by contact. III. Ageing of biocidal polyurethane coatings in water

Polyurethane coatings prepared from hydroxytelechelic polybutadiene with pendant qua-ternary ammonium salts (QAS) are able to kill microorganisms, these biocidal polymers were submitted to various ageing conditions. The activity remained constant after exposure to a very high number of bacteria (Escherichia coli). Nevertheless immersion in water caused a slow decrease of activity with time whatever the QAS examined (? N⁺R₂R′ with R = Me or Bu and R′ = n-octyl to n-hexadecyl). The phenomenon can be analysed in two stages. The first one, short (5–10 days) and limited, is due to the diffusion of a water-soluble synthesis residue. At the end of this period, the samples are still active and the activity is only due to a contact polymer-bacteria. The second stage is much slower and is accompanied by a transformation of QAS in amine. This is attributed to an equilibrium between QAS, amine, and alkyl bromide slowly shifted toward the formation of amine because of a weak solubility of alkyl bromide in water. Increasing the lipophilicity and bulkiness of the QAS substituents improves the durability of the biocidal activity. Some samples still exhibit a good activity after more than 1 year of ageing in harsh conditions. © 1993 John Wiley & Sons, Inc.     

Biocidal polymers active by contact. II. Biological evaluation of polyurethane coatings with pendant quaternary ammonium salts

Films of polyurethane were prepared by reaction of hydroxytelechelic polybutadienes carrying covalently bound quaternary ammonium salts with an aliphatic triisocyanate. These coatings exhibited high biocidal activity against Gram-positive and Gram-negative bacteria, yeasts, and moulds. It was found that many parameters controlled the bioactivity such as the time of contact between films and bacteria, the [NCO]/[OH] ratio used to prepare the cured polyurethane, the concentration of quaternary ammonium salts in the coating, and the length of the alkyl chain from C₈ to C₁₆ linked to the quaternary nitrogen atom. A secondary phenomenon of diffusion only observed with the shorter alkyl chains (C₈ and C₁₀) was shown to be due to synthesis residues. After these water-soluble impurities are eliminated, the biocidal activity remains excellent: then it is due only to a contact polymer bacteria. © 1993 John Wiley & Sons, Inc.     

Large distance flow-slide at Jono-Oge due to the 2018 Sulawesi Earthquake,Indonesia

There was a shallow earthquake in the Central Sulawesi province of Sulawesi island of Indonesia with a moment magnitude (Mw) 7.5 on 28th September 2018 at 18:02:44 local time. The event was preceded by major foreshocks and followed by aftershocks of significant magnitude. The epicenter of the main shock was in the Donggala regency of Minahasa peninsula of Central Sulawesi, approximately 70 km from the provincial capital of Palu. The earthquake was caused by the tectonic movement of the left lateral Palu- Koro fault within the Molucca Sea microplate, triggering major geotechnical failure and structural damage in Palu city and Sigi regency. Thousands of people died or are still unaccounted for, and countless others were injured. Balaroa, Petobo, Jono-Oge and Sibalaya were the worst hit mainly due to large-scale flow-slides and mud flows. It was the first time that such large-scale flow failures were triggered by an earthquake, and that the failure of very gentle sloping ground swept away whole localities. The objective of this research was to provide insight into the scale of ground failure and other infrastructural damage caused by the event, especially in Jono-Oge area, where the flow distance was longest. The authors performed preliminary and detailed surveys in the area twice by conducting Portable Dynamics Cone Penetration Test (PDCPT), collecting disturbed and undisturbed samples and using aerial drone (UAV) photography. The findings of the reconnaissance survey are described here along with subsequent data interpretation. Finally, the mechanism of the flow-slides is discussed.     

Learning nonlinear input–output maps with dissipative quantum systems

This paper proposes an efficient semi-quantum private comparison protocol (SQPC) using single photons, which allows two classical participants to securely compare the equality of their secret with the help of an almost-dishonest third party. Because of the use of single photons, the SQPC is more practical and the qubit efficiency of the proposed protocol is higher than the existing semi-quantum private comparison protocols. Moreover, the proposed protocol can resist several well-known attacks including outsider and insider’s attacks.