The effect of increasing the pulp yield by the addition of sodium borohydride (NaBH4) or polysulfide (PS) in softwood kraft cooking, i.e. enhancing the retention of glucomannan, on the physical properties of low-grammage handsheets was studied. In addition to the yield improvement, an increase in tensile index was observed, especially at lower degrees of beating. These higher yield pulps showed...

Changes in axial stress and refractive index have been measured as a function of the total UV-irradiation fluence during the formation of Bragg gratings in B/Geand Sn/Ge-codoped core fibers. For the B/Ge-codoped core fiber, a fast development of the type-I grating with a significant increase in refractive index and tensile stress in the fiber core is followed by a slow growth of the type-IIA gr...

nanofibrillated cellulose fibers were produced from unbleached kraft pulp of kenaf bast fiber. air dried and vacuum filtrated films of cellulose nanofibers were produced and their density and tensile properties were investigated. kenaf bast fiber unbleached kraft pulp has good potential for production of cellulose nanofibers by microfluidizer; so that the use of kenaf bast fiber unbleached kraf...

We study the transverse oscillatory modes of nanomechanical silicon nitride strings under high tensile stress as a function of geometry and mode index m≤9. Reproducing all observed resonance frequencies with classical elastic theory we extract the relevant elastic constants. Based on the oscillatory local strain we successfully predict the observed mode-dependent damping with a single frequency...

Carrageenans are commercially important sulfated gums found in various species of red seaweeds (Rhodophyta), wherein they serve a structural function similar to that of pectins in land plants. In this study, carrageenan was used independently or in combination with cationic polyacrylamide (CPAM) and/or Al2(SO4)3 to explore its application as a dry strength additive in papermaking. Strength inde...

Studies on strength delivery and related fields have so far concentrated on finding the locations in the mill where fibres are damaged and what the damages consist of. However, fibres will invariably encounter mechanical stresses along the fibreline and in this thesis a new concept is introduced; the vulnerability of fibres to mechanical treatment. It is hypothesised that fibres with different ...

Various studies have reported a significant reduction in tensile bond strength of brackets when bonding is carried out immediately after bleaching. The purpose of this investigation was to determine the effect of an antioxidant agent on the tensile bond strength values of metal brackets bonded with composite resin to human enamel after bleaching with carbamide peroxide (CP). A total of 80 extra...

Glipizide is mainly absorbed in the proximal areas of the gastrointestinal tract. The purpose of this study was formulation and evaluation of mucoadhesive films to prolong the stay of drug in its absorption area. Glipizide was formulated in a mucoadhesive film that could be retained in the stomach for prolonged intervals. Polymeric films were designed with various compositions of hydroxypropyl ...

objective: the objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments. materials and methods: forty two glazed ceramic disks were assigned to three groups. in the first and second groups the specimens were etched with 9.5% hydrofluoric acid (hfa). subsequently in first group, ceramic primer and...