Tanning with Aluminum-Gallic Acid Complex

To figure out how polyphenol compounds with a low molecular weight helped in aluminum tannage, a complex of gallic acid and aluminum as well as its application to the tanning of hide powder was studied in this paper. Precipitation points of aluminum chloride solution with different concentrations of gallic acid were measured to guide the basification in hide powder tannage. UV-Visible spectra showed that gallic acid and aluminum would form soluble complexes in aqueous solution and the complexation reaction was pH reliable. Through stoichiometry studies, generations of the 1:2 complex under pH 4.0 and 2:3 complex under pH 4.5 were discovered. Results of stoichiometry studies and Fourier Transform Infrared Spectroscopy (FTIR) spectra confirmed that aluminum-gallic acid complex played the role of links which connected collagen molecules rather than gallic acid or aluminum forming individual bridges with collagen. According to the results of differential scanning calorimetry (DSC) and thermal gravity analysis (TGA), denaturation temperature (Td) of hide powder tanned with different methods, such as aluminum, gallic acid-aluminum combination or aluminum-gallic acid complex, was 76.1°, 82.8° and 85.5°C respectively, and the initial decomposition temperature for the aluminum-gallic acid complex tannage was 300.7°C, also higher than those for another two methods. Furthermore, the results of inductive coupled plasma emission spectroscopy (ICP) showed that after washing for 12 h, the Al2O3 content in hide powder tanned with complex could be maintained at 93.42% of that in unwashed samples, which was the highest among three tanning methods.

In-situ porosity recognition for laser additive manufacturing of 7075-Al alloy using plasma emission spectroscopy

Poor quality and low repeatability of additively manufactured parts are key technological obstacles for the widespread adoption of additive manufacturing (AM). In-situ monitoring and control of the AM process is vital to overcome this problem. This paper describes the combined artificial intelligence and plasma emission spectroscopy to identify the porosity of AM parts during the process. The time- and position-synchronized spectra were collected during the directed energy deposition (DED) manufacturing process of a 7075-Al alloy part. Eighteen features extracted from spectra were coupled with the deposition qualities which were characterized by the 3D X-ray Computed Tomography (CT) scan and used to train a Random Forest (RF) classifier. The well-trained RF classifier achieved up to 83% precision for the porosity recognition of depositions. The feature importance recorded by the RF classifier indicates that the intensities of spectra at the wavelength of 414.234 (Fe I) nm and 396.054 (Al I) nm, and the kurtosis of spectra at wavelength ranges of 484–490 nm and 508–518 nm, are the most effective features for porosity recognition. The physical correlations between spectra, porosity formation, and thermal accumulation during the AM process were analyzed. This study demonstrates the great potentials, as well as challenges of plasma emission spectroscopy for in-situ quality monitoring of laser AM which allows the enhancement of AM technique.

Iron Biofortification of the Common Bean: Assessment of Bean Iron Concentration and Iron Bioavailability from Markets and Breeder Collections in East Africa

Objectives To assess the practicality and assumptions of the high Fe concentration approach for bean Fe biofortification in east Africa. Methods A collection of 76 marketplace samples (East Africa Marketplace Collection; EAMC) were assembled, consisting of multiple color classes from locations in Uganda, Rwanda, Democratic Republic of Congo, Burundi, Ethiopia, Kenya and Tanzania. In addition, because market samples can be a mixture of seed varieties within a market class, 170 samples from the Africa CIAT Collection were also assembled that represent beans of common markets in the region. Iron concentration was measured via inductively coupled plasma emission spectroscopy (ICP-ES) and Fe bioavailability via an established Caco-2 cell bioassay. Using these measures, the following assumptions of high Fe bean Fe biofortification approach were assessed: 1) the average Fe concentration in beans currently consumed in east Africa is approximately 50 μg/g (dry weight), 2) a 40 μg/g increase (target value 90 μg/g) can be sustained through traditional breeding, and 3) iron bioavailability from the biofortified bean will not decrease substantially to negate the increase in Fe concentration. Results The average EAMC bean Fe concentration was 72 μg/g, ranging from 52–93 μg/g, with a couple of outlying varieties at 105 μg/g (MAC9) and 129 μg/g (MAC49). The Africa CIAT collection averaged 67.5 μg/g with a range of 51–90 μg/g. The 18 biofortified varieties within the EAMC averaged 73 μg/g (range of 55–94 μg/g), which is essentially equal to the overall mean (70 μg/g) and range (54–93 μg/g) of the non-biofortified bean varieties in the EAMC. Using a Caco-2 cell bioassay to measure Fe bioavailability of the EAMC, the biofortified varieties did not deliver any additional Fe relative to non-biofortified varieties. Conclusions The results indicate that the assumptions of the high Fe bean breeding approach are not met in the typical east African market place. Furthermore, based on the Fe content and bioavailability data collected from this study, the biofortified bean varieties from these markets are providing no additional dietary Fe. An alternative approach for bean Fe biofortification, such as enhanced Fe bioavailability should be pursued. Funding Sources USDA.