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L. Senff, D. Hotza, J.A. Labrincha
Effect of lightweight aggregates addition on the rheological properties and the hardened state of mortars

Appl. Rheol. 21:1 (2011) 13668 (8 pages)

This paper evaluates the use of lightweight aggregates (LWA), namely perlite (PER) and vermiculite (VER) in cement mortars. The workability of mortars was defined in rheometer and flow table tests. Three distinct LWA levels were added (0 - 3, 4.5 - 7, and 9 - 10.5 wt%) requiring the use of distinct water/solids (W/S) ratios (0.18, 0.265 and 0.35, respectively). In order to evaluate the performance of such formulations in the hardened state, the flexural and compressive strength after 28 days curing was also measured. In general, LWA caused a high variation on the yield stress and spread on table, being the yield stress the best rheological parameter to be related with the flow table. PER exerts a strong impact on initial yield stress, while the effect of VER is stronger for longer rheology testing periods. The compressive strength ranged from 12.3 MPa (0 % LWA) to 2.77 MPa (PER) and 2.39 MPa (VER).

Cite this publication as follows:
Senff L, Hotza D, Labrincha JA: Effect of lightweight aggregates addition on the rheological properties and the hardened state of mortars, Appl. Rheol. 21 (2011) 13668.

A.T. Vendrusculo, D. Hotza, C.M. Gomes, M.G.N. Quadri
Rheology of Star Fruit Pulp (Averrhoa Carambola L.)

Appl. Rheol. 16:1 (2006) 26-31

Rheological properties of food fluids are useful for quality control, texture evaluation, and food structure determination. The rheological behavior is dependent on the size, form and concentration of solids in suspension and the system structure. Star fruit (Averrhoa carambola L.) pulp was obtained from the crude fruit and treated enzymatically, pasteurized and homogenized at 11000 rpm for 2 min and 22000 rpm for 5 min. The pulp presented Newtonian characteristics with R2 values greater than 0.98. Enzymatic treatment under 55 C for 1 h reduced the crude pulp viscosity from 1.84 to 1.22 mPa.s. Pasteurization under 100 C for 10 min increased the viscosity at around 26% in relation to the crude pulp, resulting in a turbid and homogeneous product. To evaluate the influence of the insoluble solids, filtration or concentration to 50% from the initial volume were carried out using laboratory procedures. Filtration of the pasteurized pulp promoted a viscosity decrease of 60% while concentration increased the viscosity from 2.28 to 7.98 mPa.s

Cite this publication as follows:
Vendrusculo AT, Hotza D, Gomes CM, Quadri MGN: Rheology of Star Fruit Pulp (Averrhoa Carambola L.), Appl. Rheol. 16 (2006) 26.

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