Reservoir Operation Optimization: A Nonstructural Solution for Control of Seepage from Lar Reservoir in Iran

Abstract

In this paper, the results of utilizing a deterministic dynamic programming model for operation of Lar Reservoir in Iran are discussed. This reservoir has experienced extensive seepage from the start of its operation. The optimization model consists of a three-step cycle, which began with the optimization of reservoir operation for a given set of streamflows. The optimal policies are then analyzed in a regression procedure to obtain a set of operating rules. After the first run, operating rules from the previous run were placed as a new constraint on the water releases with some pre-assigned tolerance and the cycle continues. The model also consisted of mathematical functions for modeling the seepage from Lar Reservoir as a function of storage head in the reservoir. The loss function in the model was also modified in order to incorporate parameters that reduce the seepage. Results of different scenarios showed the significant effect of optimal policies on reduction of seepage and increasing the reliability of water supply to Tehran Metropolitan Area. A pumping station was also proposed to utilize the inactive part of the reservoir, in access of over 100 MCM, in order to reduce the seepage. The effectiveness of different pumping capacities to reduce the seepage was also investigated.     

Chemical,textural, rheological,and sensorial properties of wheyless feta cheese as influenced by replacement of milk protein concentrate with pea protein isolate

Replacement of milk protein with protein isolates from vegetable resources can significantly influence the characteristics of feta whey less cheese and also decrease the cost of final production. In this study, various blends of milk protein concentrate (MPC) and pea protein isolate (PPI) were mixed at levels of 12% MPC and 0% PPI (MP0), 10% MPC and 2% PPI (MP2), 9% MPC and 3% PPI (MP3), 8% MPC and 4% PPI (MP4), 7% MPC and 5% PPI (MP5), 6% MPC and 6% PPI (MP6) and used in the manufacture of wheyless feta cheese. The chemical, textural, rheological, and sensorial properties, as well as the microstructure of the cheese samples, were evaluated after 1, 15, and 30 days of storage. The general linear model procedure of SAS statistical software was used for statistical analysis. Duncan's multiple range tests was used to compare the means of different treatments. The results showed that all properties of the cheeses were influenced by different levels of PPI due to different total solids content. The use of high concentrations of PPI resulted in a more open protein network, softer structure and decreasing the storage (G′) and loss (G″) moduli in the cheeses. Sensory evaluation of the samples revealed that total score in terms of flavor, texture and overall acceptability was gradually decreased with increasing PPI levels, but still preferable for the panelists. Furthermore, for each sample, with increasing levels of PPI, the whiteness and the greenness were decreased, but the yellowness was increased.     

Moisture uptake and resulting mechanical response of biobased composites. I. constituents

The mechanical properties of the biobased fiber and resins have been characterized and moisture influence on the behavior of these materials has been studied. Commercially available biobased thermoset resins (Tribest, EpoBioX, Palapreg, Envirez SA, and Envirez SB) and regenerated cellulose fibers (Cordenka) have been conditioned at different levels of relative humidity (as received, dried, 41, 70, and 90%) to obtain materials with different moisture content. The following properties of polymers were measured: tensile, flexural (3P‐bending), impact strength (unnotched Charpy), and fracture toughness (compact tension). The results of characterization of biobased thermosets were compared against data for epoxy Araldite LY556, which is used as reference resin. RCF bundles (with and without twist, extracted from fabric) as well as single fibers separated from these bundles were tested in tension. In general biobased resins performed well, moreover EpoBioX showed better properties than synthetic epoxy. POLYM. COMPOS., 35:1150–1159, 2014. © 2013 Society of Plastics Engineers     

Moisture uptake and resulting mechanical response of bio‐based composites. II. composites

The durability of entirely bio‐based composites with respect to the exposure to elevated humidity was evaluated. Different combinations of bio‐based resins (Tribest, EpoBioX, Envirez) and cellulosic fibers (flax and regenerated cellulose fiber rovings and fabrics) were used to manufacture unidirectional and cross‐ply composite laminates. Water absorption experiments were performed at various humidity levels (41%, 70%, and 98%) to measure apparent diffusion coefficient and moisture content at saturation. Effect of chemical treatment (alkali and silane) of fibers as protection against moisture was also studied. However, fiber treatment did not show any significant improvement and in some cases the performance of the composites with treated fibers was lower than those with untreated reinforcement. The comparison of results for neat resins and composites showed that moisture uptake in the studied composites is primarily due to cellulosic reinforcement. Tensile properties of composites as received (RH = 24%) and conditioned (RH = 41%, 70%, and 98%) were measured in order to estimate the influence of humidity on behavior of these materials. Results were compared with data for glass fiber reinforced composite, as a reference material. Previous results from study of unreinforced polymers showed that resins were resistant to moisture uptake. Knowing that moisture sorption is primarily dominated by natural fibers, the results showed that some of the composites with bio‐based resins performed very well and have comparable properties with composites of synthetic epoxy, even at elevated humidity. POLYM. COMPOS., 36:1510–1519, 2015. © 2014 Society of Plastics Engineers