Deployment Dynamics of a Small Carbon Fiber Tape-Spring UAV Wing

Many mechanisms exist for folding and deploying wing surfaces on micro-scale unmanned air vehicles. A rolling tape-spring style wing offers simple construction, small mass, and compact packed volume. Deployment of the wing during flight would be advantageous for autonomous MAV launch, however the deployment process presents potential buckling issues due to the deployment dynamics and aero-structure interaction. In this study a finite element model of an example wing is developed and its deployment dynamics are compared against an experimental model. Additionally, elastic material properties are estimated using model updating, comparing predicted natural frequencies to those measured by a laser vibrometer experimentally. To better evaluate the deployment dynamics of the finite element model, in experiment a vacuum chamber is used to decouple the aero and structural dynamics. The computational results are compared with the experimental finding and good agreement was observed.

HERITABILITY OF PHYSICAL PROPERTIES AND OTHER QUALITY TRAITS IN TIMOTHY

An important aspect in breeding for improved quality is to identify and evaluate new selection criteria. The purposes of this work were (1) to evaluate genetic variability for three physical properties in timothy (Phleum pratense L.): packed volume (PV), water retention (WR) and water solubility (WS); these traits being potential indicators of voluntary intake, (2) to estimate their heritability, and (3) to determine the genetic relationship between these physical properties and some other quality traits. In this study, 25 clones and their half-sib families were evaluated over a 3-yr period for dry matter yield (DMY), crude protein (CP), digestibility (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF) and three physical properties. The genetic analysis revealed that most genetic variability was additive for these traits. Narrow sense heritability estimates for PV (0.77–0.93), WR (0.70–0.96) and WS (0.33–0.67) suggest that genetic gains could be expected from selection. The phenotypic correlations indicated that PV, WR and WS were positively correlated with CP and IVDMD but negatively correlated with NDF and ADF. The exception was WS, which was not correlated with CP. According to these results, selection for either lower PV or lower WR would have a detrimental effect on CP, IVDMD, NDF and ADF while selection for WS would have little if any effect on these traits.Key words: Digestibility, packed volume, water retention, water solubility, fiber

GENETIC VARIABILITY IN THE PHYSICAL PROPERTIES AND OTHER QUALITY TRAITS OF TIMOTHY

The breeding of timothy (Phleum pratense L.) is mainly targetted at improving the nutritive value of the crop. Three physical properties, packed volume (PV), water retention (WR) and water solubility (WS) have been suggested as indirect measurements of voluntary intake. Variation for these three traits was estimated at the early heading and the flowering stages for 2 consecutive years within four timothy populations (Itasca, Labelle, Pronto and Richmond). Significant genetic variation was observed for PV, WR, WS, plant height (PH), dry matter yield (DMY), crude protein (CP), and digestibility (IVDMD) but the magnitude of the variation was inconsistent among populations. Curiously, PV, WR and WS seemed to improve from early heading to flowering. Significant variation was observed in all four populations for PV, in three populations for WS and in only two populations for WR. The different interactions between genotypes, years and maturities indicated that different selection strategies might be needed according to the base population used. The correlations within and between maturity stages among PV, WR, WS, PH, DMY, CP and IVDMD were inconsistent among populations. The presence of genetic variation in timothy for the three physical properties under study suggests that improvement of these traits may be possible through breeding. However, further information is needed on the heritability and the evolution of these traits with advancing maturity.Key words: Timothy, Phleum pratense L., packed volume, water retention, water solubiliy, forage quality

ESTIMATION OF THE NUTRITIVE VALUE OF SILAGES

Forty-eight wethers were used to determine voluntary intake and digestibility of eight silages made from pure swards of legumes and grasses. Chemical and physical characteristics of silages were measured and related to dry matter intake, digestibility coefficients and digestible nutrient intakes by means of simple correlation and linear regression analyses. Intakes of dry matter (DM), digestible energy, digestible protein and total digestible nutrients were correlated negatively with percentage cell walls (r = −0.87) and positively with crude protein (r = 0.92). Lignin and the logarithm of (lignin × 100/acid detergent fiber) were highly correlated to cell walls digestibility (r = 0.98). There was a close relationship between protein digestibility and crude protein content (r = 0.99). Dry matter digestibility was accurately estimated by a summative equation (r = 0.74). The physical characteristics (packed volume and water solubility) of the silages were not well correlated to either digestibility coefficients or intake. The nutritive value of good quality, well-preserved grass and legume silages was satisfactorily predicted from laboratory analyses of crude protein and cell wall components. The applicability of the equations developed in this study should be tested using a larger number of silages. Key words: Nutritive value, forages, silages, sheep

Isolation, characterization and synthesis of α-foetoprotein from neonatal-rat skin

Monospecific anti-[rat alpha-foetoprotein(alpha-FP)] immunoglobulin G was coupled to CNBr-activated Sepharose-4B (4.5 mg/ml packed volume of gel) to yield an adsorbent. The immunoaffinity column was used to isolate alpha-FP from neonatal-rat skin. Purified skin alpha-FP was found to be immunologically and electrophoretically similar to serum alpha-FP. It yielded a single band with mol.wt. 68000 on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. However, on polyacrylamide-gel electrophoresis under non-denaturing conditions, the alpha-FP displayed slow- and fast-moving variants similar to those observed in serum alpha-FP. A Scatchard plot of oestradiol binding to the alpha-FP yielded an association constant of 2.5 × 10(9)M-1 by dextran-coated-charcoal and 0.75 × 10(8)M-1 by Sephadex-gel-filtration procedures respectively. Skin explants from newborn rats were found to incorporate [14C]leucine into immunoprecipitable intracellular alpha-FP. Cycloheximide inhibited the synthesis of alpha-FP in skin explant culture. Our results indicate that newborn-rat skin contains alpha-FP that is similar to serum alpha-FP and which may arise in neonatal-rat skin as a result of synthesis in situ.

THE RELATIONSHIP BETWEEN VOLUNTARY INTAKE AND THE PHYSICAL PROPERTIES OF FORAGES

Twenty male sheep (38.4 ± 0.2 kg body weight) were used to study physical and chemical properties of hays affecting voluntary intake. Of the eight forages studied, four were pure cultivars and four were mixed hays obtained from local farmers. Packed volume, water retention and dry matter (DM) solubility were determined in samples either chopped (as fed) or ground (20 mesh). Packed volume and DM solubility of the ground samples were highly correlated with voluntary intake values for each hay (r = −0.97 and r = 0.94 for packed volume and DM solubility, respectively, n = 8, P < 0.01). The intake of each sheep could also be predicted, although less accurately, from DM solubility values (r = 0.87, n = 40, P < 0.01). The soluble fraction contained mainly nitrogen, simple sugars and minerals. The significance of bulk volume and solubility of hays in the physiological mechanism controlling voluntary intake is discussed. Key words: Forage evaluation, forage intake, sheep

FFECTS OF DIETARY FLOUR AND OIL FROM TOWER RAPESEED ON FOOD INTAKE, WEIGHT GAINS, NUTRIENT DIGESTIBILITY, ENERGY UTILIZATION AND BODY COMPOSITION OF RATS

Rats were fed diets containing 15% protein, 10% fat and 4.7 kcal/g in the form of: (1) soybean flour–corn oil (SBF/CO), (2) Tower rapeseed flour–corn oil (RSF/CO) and (3) Tower rapeseed flour–Tower rapeseed oil (RSF/RSO). Rats fed the SBF/CO diet ate more and grew faster than rats fed the RSF diets (P < 0.05). However, rats fed the RSF/RSO diet converted food to weight gain more efficiently than rats receiving the SBF/CO diet (P < 0.05). The digestibility of the dry matter (92%), energy (94%) and protein (88%) of the RSF diets was higher than that of the SBF diet (P < 0.01). Digestibility of the RSO was higher than that of the CO only when SBF was used as source of dietary protein. The net protein utilization of the diets throughout the experiment was similar (43–48%). Energy retention as percent of intake was similar for all diets (20–26%); however, rats receiving the RSF/RSO diet deposited a greater proportion of the caloric intake as tissue protein than rats receiving the SBF/CO diet (10.0 vs. 8.8%, respectively, P < 0.05). Body composition after 7 days on the experimental diets was not affected by the dietary treatments. Heart weights (mg DM/g body DM) of rats fed the RSF/RSO diet were greater than those of rats receiving the SBF/CO diet (4.3 vs. 3.5 mg/g body DM, respectively, P < 0.05). After 21 days, rats fed the SBF/CO diet had deposited more body fat than rats receiving the RSF diets (12.7 vs. 9.7 and 10.1% for SBF/CO, RSF/CO and RSF/RSO respectively, P < 0.05). No other differences in body composition were observed. The nutritive value of Tower rapeseed flour and oil was higher than that of soybean flour and corn oil. No toxic effects were observed from feeding rapeseed flour or oil to rats. However, the consumption of rapeseed flour was lower than that of soybean flour, possibly due to gut fill, since the "packed volume" occupied by the RSF diet was 1.5 times larger than that of the SBF diet. Texture and palatability of the flours may have also contributed to the differences in intake.