A combined theoretical and experimental investigation of the valorization of mechanical and thermal properties of the fly ash-reinforced polypropylene hybrid composites

Journal of Materials Science - Fly ash (FA) particles were surface modified with cetyltrimethylammonium bromide (Ctab) and hybridized with graphene oxide (GO) and carboxymethyl cellulose (CMC)...     

Luminescence properties of Eu3+- and Tb3+-doped δ-Bi2O3 stabilized by Th4+ substitution

The extent of incorporating Eu³⁺ and Tb³⁺ for bismuth in the oxygen-deficient fluorite structured Bi_0.50Th_0.50O_y has been examined together with the comprehension of their luminescence characteristics. The samples were synthesized by solution combustion method from which doping limits of Eu³⁺ and Tb³⁺, respectively, in the fluorite structure was determined. Uniform distribution of constituent elements was confirmed from elemental mapping. Doping Eu³⁺ and Tb³⁺-ions introduced compressive strain and oxygen vacancies in the system. Raman spectra of doped samples confirmed the fluorite structure and revealed the existence of oxygen vacancies in them. While Tb-doped samples showed a systematic decrease in band gap with increase in dopant concentration, such systematic variation was not observed for Eu-doped samples. Conclusions about the local site symmetry around Eu³⁺ and Tb³⁺ ions in the defect fluorite structure have been drawn from the photoluminescent spectral analysis of doped samples. Energy transfer from Bi³⁺ to Eu³⁺ and Tb³⁺-has been observed in these samples. The Judd-Ofelt analysis has been carried out to understand luminescence characteristics in these samples.     

Preparation of pH‐sensitive hydrogels by graft polymerization of itaconic acid on tragacanth gum

Graft polymerization of itaconic acid on tragacanth gum (TG) was carried out using potassium persulfate as initiator to develop smart hydrogels for drug delivery systems. The effect of the grafting parameters on the degree of grafting was investigated. The grafting was significantly influenced by the reaction medium, the reaction temperature and the monomer concentration. The monomer dependency of the system was found to be 1.52. The hydrogels were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X‐ray diffraction. The grafted TG had an amorphous nature and exhibited excellent swelling in water and strong dependence on the pH of the medium. The grafted TG showed pH‐dependent release of ciprofloxacin which offers the possibility of using these materials in colon‐specific drug targeting for human healthcare systems. © 2018 Society of Chemical Industry     

Optimal just-in-time schedules for flexible transfer lines

Flexible transfer lines or mixed-model assembly lines are capable of diversified small-lot production due to negligible switch-over costs. With these lines, it is possible to implement just-in-time (JIT) production, which involves producing only the necessary parts in the necessary quantities at the necessary times. The problem of sequencing flexible transfer lines according to the JIT philosophy can be formulated as a nonlinear integer programming problem. Heuristic algorithms to solve the problem have appeared in the literature. In this paper, we show that the problem can be explicitly reduced to an assignment problem. Thus, we provide an efficient algorithm for an optimal solution to the JIT sequencing problem.This research is supported in part by NSERC grants A4619 and OPG0105675, General Motors of Canada, and The Manufacturing Research Corporation of Ontario. Helpful comments from Kathy Stecke, Ram Rachamadugu, the referees, and the Associate Editor are gratefully acknowledged.     

Expression of deletion constructs of bovine {beta}-1, 4-galactosyltransferase in Escherichia coli: importance of Cysl34 for its activity

Bovine ß-1, 4-galactosyltransferase (ß-1,4-GT; EC 2.4.1.90 [EC] ) belongs to the glycosyltransferase familyand as such shares a general topology: an N-terminal cytoplasmictail, a signal anchor followed by a stem region and a catalyticdomain at the C-tenninal end of the protein. cDNA constructsof the N-terminal deleted forms of ß-1, 4-GT wereprepared in pGEX-2T vector and expressed in E.coli as glutathione-S-transferase(GST) fusion proteins. Recombinant proteins accumulated withininclusion bodies as insoluble aggregates that were solubilizedin 5 M guanidine HCl and required an ‘oxido-shuffling’reagent for regeneration of the enzyme activity. The recombinant(ß-1, 4-GT, devoid of the GST domain, has 30–85%of the sp. act. of bovine milk ß-1, 4-GT with apparentK_ms for N-acetylglucosamine and UDP-galactose similar to thoseof milk enzyme. Deletion analysesshow that both (ß-1,4-GT and lactose synthetase activities remain intact even inthe absence of the first 129 residues (pGT-dl29). The activitiesare lost when either deletions extend up to residue 142 (pGT-dl42)or Cysl34 is mutatedto Ser (pGT-dl29C134S). These results suggestthat the formation of a disulfide bond involving Cysl34 holdsthe protein in a conformation that is required for enzymaticactivity.     

Stability of real-time lot scheduling policies for an unreliablemachine

A single-machine multiproduct manufacturing system with random breakdowns and random repair times is considered. Under a weak capacity condition on the system it is shown that the total work-in-progress (WIP) is a recurrent stochastic process. By replacing the stochastic model by a deterministic one with preventive maintenance activities scheduled on a regular basis or by strengthening the capacity condition, the boundaries of WIP and expected WIP, respectively, over time can be shown     

Neurodevelopmental outcome at age two years amongst very low birth weight infants: results from a district general hospital

SCOPE OF THE STUDY: We studied the possibility to examine position and determination of IOL and capsular bag supporting ring. PATIENTS AND METHODS: We showed in ten human eyes the identification of capsular bag supporting ring (PMMA, 12,5 mm open diameter) and intraocular lenses (IOL, 13,5 mm diameter) and haptics by ultrasound biomicroscopy in radar and limbus parallel scans 12 to 18 months post operation. RESULTS: Both alloplastic implantates show typical sceems of reflection and could be differentiated by ultrasoundbiomicroscopy. In eyes with zonulolysis up to 6 hours a good centration of capsular bag supporting ring and IOL had been seen, with more zonulolyses a slight subluxation could been shown. CONCLUSION: Ultrasound biomicroscopy is a good method to determine the position of intraocular lens and capsular bag supporting ring.     

Recent Progress in Super Hydrophobic/Hydrophilic Self-Cleaning Surfaces for Various Industrial Applications: A Review

The growing interest in self-clean coatings owes to their low maintenance cost, high durability, and immense potential applications. Such coatings, for instance, may offer useful resistance against fouling, icing, smear, corrosion and possesses oil-water separation capability. Hence, the design and development of self-cleaning materials is an area of significant interest to researchers worldwide. This exploration prospectus critically reviews and highlights various types of self-cleaning surfaces, their applications, working mechanisms, and fabrication techniques used globally. The comprehensive literature study suggests that an extensive study of surface behavior towards water and oil may jointly determine its self-cleaning nature.     

Intelligent stuttering speech recognition: A succinct review

Stuttering speech recognition is a well-studied concept in speech signal processing. Classification of speech disorder is the main focus of this study. Classification of stuttered speech is becoming more important with the enhancement of machine learning and deep learning. In this study, some of the recent and most influencing stuttering speech recognition methods are reviewed with a discussion on different categories of stuttering. The stuttering speech recognition process is divided mainly into four segments-input speech pre-emphasis, segmentation, feature extraction, and stutter classification. All these segments are briefly elaborated and related researches are discussed. It is observed that different traditional machine learning and deep learning classification approaches are employed to recognize stuttered speech in last few decades. A comprehensive analysis is presented on different feature extraction and classification method with their efficiency.