Search Results (4)

Oil palm kernel shell ash (POFA), a byproduct of the highly cultivated agro-industrial sector in Colombia, has been widely used for its pozzolanic properties, which enhance the mechanical and durability characteristics of concrete. Six POFA samples were analyzed after undergoing drying, cutting, grinding, crushing, and calcination at temperatures ranging from 500 °C to 1000 °C. SEM-EDS/EDX analysis, X-ray fluorescence (XRF), and loss on ignition (LOI) tests were conducted to characterize its pozzolanic potential. The results revealed that the SiO₂ content increased with the calcination temperature, reaching a peak of 76.8% at 1000 °C. However, calcination at 600 °C was identified as the optimal temperature, as it balances impurity removal without inducing the formation of crystalline silica, which would negatively affect the material’s reactivity. Considering the optimal calcination temperature and the high initial LOI values, which exceeded 70% in the first calcination stage, a second calcination was performed on the 500 °C sample by increasing the temperature to 600 °C. This resulted in an LOI of 3.33%, according to ASTM C311 standards for natural pozzolans used in Portland cement concretes. Full article

In recent decades, the global use of ashes derived from agro-industrial by-products, such as oil palm kernel shells, which are widely cultivated in Colombia and other tropical regions of the world, has increased. However, the application of these ashes in engineering remains limited due to their heterogeneity and variability. This study utilized scanning electron microscopy (SEM) to assess the influence of calcination temperatures, ranging from 500 °C to 1000 °C, as well as the physical processes of cutting, grinding, and crushing, on the silica content of the studied ashes. Specifically, the sample labeled M18A-c-m-T600°C-t1.5h-tr1h, which was subjected to a calcination temperature of 600 °C and underwent cutting and grinding before calcination, followed by post-calcination crushing, exhibited the highest silica concentration. Complementary techniques such as X-ray fluorescence (XRF) and X-ray diffraction (XRD), were applied to this sample to evaluate its feasibility as an additive or partial replacement for cement in concrete. XRF analysis revealed a composition of 71.24% SiO₂, 9.39% Al₂O₃, and 2.65% Fe₂O₃, thus, meeting the minimum oxide content established by ASTM C 618 for the classification as a pozzolanic material. Furthermore, XRD analysis confirmed that the sample M18A-c-m-T600°C-t1.5h-tr1h is in an amorphous state, which is the only state in which silica can chemically react with calcium hydroxide resulting from the hydration reactions of cement, forming stable cementitious products with strong mechanical properties. Full article

This study aims to evaluate the quality of salted sun-dried meat from young bulls (Nellore cattle) fed with a diet containing 0.0, 0.5, 1.0 and 1.5% of lauric acid in the total dry matter (DM). Thirty-two Nellore bulls with initial body weight of 368 ± 32 kg were used. A linear decrease (p < 0.05) in pH and protein content of the salted sun-dried meat was observed with the inclusion of lauric acid. The moisture, ash, lipid, collagen content, water-holding capacity, cooking loss, color indexes (L*, a*, b*, C*), and shear force were not affected. Lipid oxidation at 7 days of storage increased linearly in the salted sun-dried meat. Most of the fatty acid composition of the salted sun-dried meat from the semimembranosus muscle of young bulls was not influenced (p > 0.05) by the lauric acid inclusion in the bulls’ diet. However, there was a linear increase (p < 0.05) in the SFA lauric acid (C12:0), PUFAn-3 EPA (C20:5n − 3) and DHA (C22:6n − 3), and a quadratic increase in the PUFAn-6 arachidonic (C20:4n − 6) due to lauric acid addition from palm kernel oil in the diet. There was a liner increase (p < 0.05) in the total ∑PUFA, ∑n − 6, ∑n − 3 contents of salted sun-dried meat from the semimembranosus muscle of young bulls and the h:H health index of the level of lauric acid inclusion in bull’s diet. In contrast, the thrombogenicity health index (TI) and ∑n − 6:∑n − 3 ratio content in salted sun-dried meat from the semimembranosus muscle of young bulls presented a linear decrease (p < 0.05) due to lauric acid addition in the bulls’ diet. Lauric acid (C12:0) inclusion up to 1.5% in the diet of young Nellore bull improved the fatty acid composition of the salted sun-dried meat, increasing EPA, DHA, n − 6 and n − 3, TI, and h:H indexes, which are associated with a better lipid quality of meat products, and further improves tenderness at the highest concentration. Full article

The aim of this study was to evaluate the effects of the inclusion of palm kernel oil (PKO) in a lamb diet on nutrient intake, digestibility, ingestive behavior, nitrogen balance, blood metabolites, rumen fermentation parameters, and animal performance. Three experimental trials were conducted. The treatments consisted of varying levels of PKO included in the diet, with PKO_zero = no PKO inclusion, PKO_1.3 = 1.3% addition, PKO_2.6 = 2.6% addition, PKO_3.9 = 3.9% addition, and PKO_5.2 = 5.2% addition, based on the total dry matter (DM) of the diet. With the inclusion of PKO in the diet, linear decreases in DM (p < 0.001), crude ash (p < 0.001), crude protein (CP) (p < 0.001), neutral detergent fiber (NDF) (p < 0.001), nonfibrous carbohydrate (NFC) (p < 0.001), and total digestible nutrient (TDN) (p = 0.021) intake were observed, as was an increase in ether extract (EE) intake (p < 0.001). The digestibility coefficients of NDF and NFC were not affected by PKO addition to the diet. However, the digestibility of DM (p = 0.035), EE (p < 0.001), CP (p < 0.001), and TDNs (p < 0.001) increased when PKO was added to the lambs’ diet. Reductions in N intake (p < 0.001), fecal nitrogen excretion (p < 0.001), and microbial protein production (p < 0.001) were noted with increasing PKO levels. Serum cholesterol increased (p < 0.001) while serum GGT enzyme concentrations in the blood decreased (p = 0.048) with increasing PKO levels. PKO addition had no effect on total weight gain and average daily gain; however, feed conversion improved (p = 0.001) with increasing PKO levels. The intake, digestibility, ingestive behavior, and growth performance of lambs with PKO_1.3 added to their diet were similar to animals that did not receive PKO, meaning that PKO could be an alternative energy source for growing lambs because it does not harm animal performance and can lower the cost of feed. Full article