Comparison of three‐dimensional analysis and stereological techniques for quantifying lithium‐ion battery electrode microstructures

Lithium‐ion battery performance is intrinsically linked to electrode microstructure. Quantitative measurement of key structural parameters of lithium‐ion battery electrode microstructures will enable optimization as well as motivate systematic numerical studies for the improvement of battery performance. With the rapid development of 3‐D imaging techniques, quantitative assessment of 3‐D microstructures from 2‐D image sections by stereological methods appears outmoded; however, in spite of the proliferation of tomographic imaging techniques, it remains significantly easier to obtain two‐dimensional (2‐D) data sets. In this study, stereological prediction and three‐dimensional (3‐D) analysis techniques for quantitative assessment of key geometric parameters for characterizing battery electrode microstructures are examined and compared. Lithium‐ion battery electrodes were imaged using synchrotron‐based X‐ray tomographic microscopy. For each electrode sample investigated, stereological analysis was performed on reconstructed 2‐D image sections generated from tomographic imaging, whereas direct 3‐D analysis was performed on reconstructed image volumes. The analysis showed that geometric parameter estimation using 2‐D image sections is bound to be associated with ambiguity and that volume‐based 3‐D characterization of nonconvex, irregular and interconnected particles can be used to more accurately quantify spatially‐dependent parameters, such as tortuosity and pore‐phase connectivity.     

EFFECT OF SULFUR SUPPLY ON ALLIINASE, THE FLAVOR GENERATING ENZYME IN ONIONS

The characteristic flavor of onions occurs when the enzyme alliinase (EC 4.4 1.4) hydrolyzes S‐alk(en)yl‐L‐cystene sulfoxides (ACSOs) to form sulfur‐containing volatiles, pyruvate and ammonia. Two onion cultivars, Pukekohe Longkeeper and Grano, were grown to maturity at a high (4.0 meq S/L) and low (0.25 meq S/L) sulfur supply and assayed for alliinase specific activity and enzymatically produced pyruvate. Alliinase specific activity was greater (1.3–1.7 fold) at low sulfur supply in bulbs of both cultivars. Levels of enzymatically produced pyruvate were lower at low sulfur supply. Low sulfur supply has been previously shown to decrease levels of ACSOs and their biosynthetic intermediates but increase levels of proteins involved in sulfate uptake and mobilization. Alliinase may have an endogenous role in remobilizing ACSOs during conditions of sulfur deprivation.     

VOLATILES IN A FAT-BASED FAT SUBSTITUTE MODEL COMPOUND, ESTERIFIED PROPOXYLATED GLYCEROL SOYATE

Static headspace and GC/IR-MS (capillary gas-liquid chromatography, with an infrared detector and a mass spectrometer), were used to collect, separate, identify, and quantitate the volatile products in the EPG-08 soyate sample, (esterified propoxylated glycerol, which is a model fat substitute compound with 8 moles of propylene oxide per mole of glycerol), EPG-00 soyate (essentially trans-esterified soybean oil with no added propylene oxide), and a 50:50 (v:v) mixture of the two oil samples. Each sample was heated at £192C for 12 h/day until the oil contained £20% triacylglycerol polymer. The EPG-08 soyate samples were heated for 36 h, whereas the EPG-00 soyate and the 50:50 mix samples were heated for 48 h. The major volatile decomposition products found included hexanal     

Assay Precision and Accuracy of Calcium-Dependent Proteinase Activity in Rat Skeletal Muscle

The accuracy and precision with which Ca⁺⁺-dependent proteinase (CAF) activity can be assayed in skeletal muscle tissue was determined by using two experimental approaches: (1) repeated sampling of a homogeneous batch of minced rat skeletal muscle to estimate variation among CAF assays done on fractions made from the same muscle tissue and to ascertain the effect of sample size on assays of CAF activity; and (2) comparison of CAF assays done on muscle samples of similar weights obtained from different animals that had been treated alike. Muscle CAF activity can easily be detected in 0.5g muscle samples, but the measured activity is not accurate and increases with increasing sample size. The decreased CAF activity assayed in small muscle samples seemed to originate from failure to extract all the CAF in these samples, possibly because of the different homogenizer that must be used to homogenize small samples. If a Waring Blendor is used at 8000 rpm, muscle samples must be 19g or larger to obtain accurate assays of CAF activity. The coefficient of variation for duplicate assays of CAF activity on the same P₀₄₅ crude CAF fraction was 5.85% (assay variation); for assays of CAF activity on different samples of the same muscle tissue, 7.18% (sampling variation and variation in procedure for preparing crude CAF fractions); and for assays of CAF activity on muscle tissue obtained from the different groups of animals that had been treated alike, 10.30% (animal variation). Hence, CAF activity can be measured with acceptable precision in skeletal muscle tissue, but treatments designed to alter muscle CAF activity must cause changes of at least 20% to be detectable against the natural variation of muscle CAF activity in different animals.     

Maple Syrup as Carbohydrate Source in Dry Sausage Fermentation

Maple syrup was substituted for the glucose-sucrose component of a standard dry sausage formulation to assess its feasibility in fermented meat product manufacture. Sausage batters containing either type carbohydrate were inoculated with a mixed starter culture containing Lactobacillus plantarum, Pediococcus acidilactici and Micrococcus varians. Similar acidification patterns were observed in fermenting batters containing glucose-sucrose mixtures or maple syrup, and processing yields were unaffected by carbohydrate type. However, instrumental texture measurements (shear and compression forces) revealed that sausage made with maple syrup was significantly firmer than the standard product (P≤0.05). Maple syrup could be used in the manufacture of novel fermented meat products.     

Sulfite Residues in Maraschino Cherries

A survey of 53 samples of maraschino cherries from 14 different processors revealed that total sulfite residues averaged 52.3 ± 44.7 ppm. However, 58.5% of the samples had less than 40 ppm total SO₂, while only 7.6% had greater than 120 ppm total SO₂ indicating that the distribution was skewed in the direction of lower residue levels. Free sulfite residues in the 53 samples were considerably lower averaging 14.2 ± 7.1 ppm. With free SO₂ levels, 35.8% of the samples had less than 10 ppm free SO₂, while only 5.7% had greater than 30 ppm free SO₂. With an average serving size of one cherry (3 - 7g), maraschino cherries would contribute only 0.16 – 0.37 mg per serving of total sulfites as SO₂.     

Sintering of MgF2-LiF Solid Solutions

The influence of additions of 0, 2, 3.5, and 5% LiF on the sintering kinetics of MgF₂ were studied using microcylindrical samples on a hot-stage microscope. The sintering rate of MgF₂ was markedly enhanced, doubling at 650°C when the LiF was increased from 3.5 to 5 mol%. An approximate model is suggested explaining the observed sintering enhancement based on the increased concentration of fluorine ion vacancies.     

Integrating Communication and Engineering Education: A Look at Curricula,Courses, and Support Systems

In this article we point to the ways in which engineering and communication disciplines can work together to ensure the ABET criterion that encompasses effective communication is represented in engineering curricula. Drawing upon examples from several universities in North America, we offer useful portraits of writing across the curriculum approaches, interdisciplinary courses, integrated programs, and a variety of support systems including writing and communication centers and online resources. As we develop increased awareness of the importance of including communication instruction in engineering curricula, the variety of possibilities presented in this article can help us integrate communication and engineering education.     

SENSORY AND INSTRUMENTAL EVALUATION OF TEXTURE OF COOKED AND RAW MILLED RICES WITH SIMILAR STARCH PROPERTIES

Three pairs of milled rices with similar starch properties (low gelatinization temperature waxy, and low gelatinization temperature low amylose, and intermediate gelatinization temperature intermediate amylose) were assessed for cooked rice properties by two industry taste panels and for raw and cooked rice properties by 30-member Filipino consumer panels. Only slight differences in texture within pairs were noted by the two industry taste panels who had not been trained to assess boiled raw rice or waxy rice. The Filipino consumer panel gave significantly higher ranked scores for one low-amylose variety in both raw and cooked forms. Malagkit Sungsong suman sa antala was ranked higher than modern waxy rices. Instrumental methods for translucency and whiteness of raw rice and Instron hardness and stickiness of cooked rice were not able to detect differences perceived by the Filipino consumer panels.