In this work, slices of yellow onions (Allium cape) with a diameter of (6.7 ± 0.05) cm and a thickness of (1 ± 0.05) cm are dehydrated in a drying oven at two temperatures: 40 °C and 90 °C. The average initial mass and water content of the samples are 32.61 g and 92.13%, respectively. The microbial flora in moulds and yeast is also enumerated before and after drying. An experiment plan of two variables, namely drying time and temperature, is followed to optimize the process tests. The moisture content is taken as a response. The interactions between operating variables are shown and a mathematical model is established expressing, thus, the variation of the moisture content of the onion slices as a function of the temperature and the drying time. A correlation of experimental results and calculations is indeed established. The results show that drying duration decreases with increasing temperature and water content of onion slices decreases from 92.13% to 4.5% during 2595 minutes, and from 92.13% to 9.47% during 1245 minutes, at 40 °C and 90 °C, respectively. Also, the experimental results lead to the appropriate choice of the temperature and the drying time in order to reach adequate moisture content. Finally, Oven drying of the yellow onions with determined dimensions eliminates the moulds to desired and encouraging values.
Landslides, fault movements as well as shrink/swell soil displacements can exert important additional loadings on soil buried structures such as pipelines. These loadings may damage the buried structures whenever they reach the strength limits of the structure material. This paper presents a two-dimensional plane-strain finite element analysis of an 800 mm diameter water supply pipeline buried within the expansive clay of the Ain-Tine area (Mila, Algeria), considering the unsaturated behavior of the soil under a rainfall infiltration of 4 mm/day intensity and which lasts for different time durations (8, 15 and 30 days). The simulations were carried out using the commercial software module SIGMA/W and considering different initial soil suction conditions P1, P2, P3 and P4. The soil surface heave and the radial induced forces on the pipeline ring (i.e., Axial , Shear forces and bending moments ) results indicated that following the changes of suction the rainfall infiltration can cause considerable additional loads on the buried pipeline. Moreover, these loads are proportionally related to the initial soil suction conditions as well as to the rainfall infiltration time duration. The study highlighted that the unsaturated behavior of expansive soils because of their volume instability are very sensitive to climatic conditions and can exert adverse effects on pipelines buried within such soils. As a result, consistent pipeline design should seriously consider the study of the effect of the climatic conditions on the overall stability of the pipeline structure.
The present work aims to investigate the feasibility to use date palm waste as reinforcement to improve durability and performance of concrete. Four formulations (0 wt %, 5 wt %, 10 wt % and 15 wt %) were prepared according to the date palm fibers weight contents. The performance of all these formulations was studied in terms of swelling, drying shrinkage, weight change, compressive strength and volume change. The investigations were performed by exposing the samples to various environments: immersion in water, drying, salts exposure and cyclic wetting/drying. The results revealed that mortar reinforced with date palm fibers offers better shrinkage prevention, and thus allows decreasing the cracking effect. Moreover, the composites prepared with high content of natural fibers showed better resistance against sulphuric acid attack and therefore better resistance to deterioration. A significant enhancement in mechanical behavior following alkali treatment was recorded. Finally, date palm fibers can mainly contribute for minimizing the deterioration of cement mortar composites following cyclic wetting and drying
