Effect of substituting guinea grass with sunflower hulls on production performance and digestion traits in fattening rabbits

[EN] The objective of this study was to evaluate the use of sunflower hulls (SH) to substitute guinea grass (GG), traditionally used as a fibre source in the diets of fattening rabbits, on production performance, coefficients of total tract apparent digestibility (CTTAD) of nutrients, gastrointestinal tract development and caecal fermentation. A total of 160 mixed sex Hyla commercial meat rabbits were allocated to 4 experimental groups (40 per treatment) differing in the SH level inclusion in the diet offered to rabbits from 40 to 90 d of age: 0, 30, 60 and 90 g/kg on as-fed basis: SH0, SH30, SH60 and SH90 groups, respectively. Growth performance was recorded from 47 to 90 d of age, CTTAD of nutrients from 86 to 90 d of age, and gastrointestinal tract development, caecal fermentation and carcass traits were determined at 90 d of age. Increasing substitutions of SH in the diet indicated effects on growth performance, as higher feed intake and lower feed efficiency were observed in SH90 compared with SH0 (P-linear<0.05). Moreover, the higher SH substitution diet (SH60 and SH90) increased the relative caecum weight (P-linear<0.05). A linear negative effect of SH inclusion was observed for the digestibility of neutral detergent fibre (CTTAD from 0.294 to 0.232) and acid detergent fibre (CTTAD from 0.182 to 0.136; P-linear<0.05). Dietary SH substitution level had a quadratic effect on the villus height of the duodenum, jejunum and ileum obtained (P-quadratic<0.05), and the highest were observed in the SH60 group. There was a quadratic effect on the pH of caecum content (P-quadratic<0.05), and the lowest was 6.08 in SH30 group. The total volatil fatty acids increased linearly with increasing SH in diets (from 71.11 to 76.98 mmol/L; P-linear<0.05), and when dietary SH increased, the proportion of acetate tended to increase (P-linear<0.05), and the proportions of propionic and butyric were decreased (P-linear<0.05, respectively). Substitution of GG with SH had no effect on carcass characteristics and meat quality. The current work shows that SH can replace up to 60 g/kg in diets for fattening rabbits, with no adverse impact on aspects of production performance or digestion traits.This study was supported by the earmarked fund for Modern Agro-industry Technology Research System (CARS-43-B-1) and Funds of Shandong “Double Tops” Programme.Liu, G.; Sun, C.; Zhao, X.; Liu, H.; Wu, Z.; Li, F. (2018). Effect of substituting guinea grass with sunflower hulls on production performance and digestion traits in fattening rabbits. World Rabbit Science. 26(3):217-225. https://doi.org/10.4995/wrs.2018.9375SWORD21722526

Mechanical Properties of Thermoplastic Variable-Angle Composite Laminations for Conical Shells

Thermoplastic composite automated fiber placement technology, as one of the extreme manufacturing technologies for large or extra large composite components with complex surface shapes, has been widely used in the field of aerospace vehicles. This paper takes 8 lamination groups with different initial placement angles generated by the conical shell variable angle placement algorithm as research objects. Variable angle placement algorithm for conical shell and finite element model establishment method for thermoplastic composite laminations of variable angle with different initial placement angles are presented. Static, modal and buckling analyses are conducted for each group. The results show that stress-strain relation, modal and buckling strength of variable-angle laminations vary regularly with the initial placement angle.Технология автоматической укладки термопластичного композитного волокна, являющаяся одной из радикальных технологий получения больших или очень больших компонентов композитов с комплексными формами поверхности, широко используется в авиационно-космической промышленности. В качестве объектов исследования использовали восемь групп слоистых материалов с различными углами конструктивного размещения, которые были созданы с помощью алгоритма размещения переменного угла конической оболочки. Представлены алгоритм размещения переменного угла для конической оболочки и модель на основе метода конечных элементов для термопластичных слоистых композитов с переменным углом. Для каждой группы материалов проведены статистический анализ, исследование методом разложения по собственным формам и расчет устойчивости. Установлено, что зависимость напряжение–деформация, модальная прочность и прочность при продольном изгибе слоистых материалов с переменным углом периодически изменяются в зависимости от угла конструктивного размещения.Технологія автоматичного укладання термопластичного композитного волокна, що є однією з радикальних технологій отримання великих або дуже великих компонентів композитів із комплексними формами поверхні, широко використовується в авіаційно-космічній промисловості. Об’єктом дослідження слугували вісім груп шаруватих матеріалів із різними кутами конструктивного розміщення, які отримано за допомогою алгоритма розміщення змінного кута конічної оболонки. Представлено алгоритм розміщення змінного кута для конічної оболонки і модель на основі методу скінченних елементів для термопластичних шаруватих композитів зі змінним кутом. Для кожної групи матеріалів проведено статистичний аналіз, дослідження методом розкладання за власними формами і розрахунок стійкості. Установлено, що залежність напруження–деформація, модальна міцність і міцність при поздовжньому згині шаруватих матеріалів зі змінним кутом періодично змінюються в залежності від кута конструктивного розміщення

Effect of substituting guinea grass with soybean hulls on production performance and digestion traits in fattening rabbits

[EN] The objective of this study was to evaluate the use of soybean hulls (SH) to substitute guinea grass (GG), traditionally used as fibre source in the diets of fattening rabbits on performance, coefficients of total tract apparent digestibility (CTTAD) of nutrients, gastrointestinal tract development and caecum fermentation. A total of 160 mixed sex Hyla commercial meat rabbits were allocated to 4 experimental groups (40 per treatment) differing in the SH level inclusion in the diet offered to rabbits from 40 to 90 d of age: 0, 50, 100 and 200 g/kg as-fed basis: SH0, SH50, SH100 and SH200 groups, respectively. Growth performance was recorded from 40 to 90 d of age, CTTAD of nutrients from 86 to 90 d of age, and gastrointestinal tract development, caecum fermentation and carcass traits were determined at 90 d of age. Average daily feed intake and the feed/gain ratio were lower in SH100 and SH200 groups than in SH0 group (P0.05). In conclusion, our results suggest that SH can substitute GG in the diets of fattening rabbits up to 200 g/kg in diet with no adverse effects on the growth performance, feed efficiency, carcass traits and meat quality.This study was supported by the earmarked fund for Modern Agro-industry Technology Research System (CARS-44-B-1).Shang, S.; Wu, Z.; Liu, G.; Sun, C.; Ma, M.; Li, FC. (2017). Effect of substituting guinea grass with soybean hulls on production performance and digestion traits in fattening rabbits. World Rabbit Science. 25(3):241-249. https://doi.org/10.4995/wrs.2017.6654SWORD24124925

Coalescence dynamics of size-selected gold clusters studied by time-resolved transmission electron microscopy

Coalescence dynamics of size-selected gold (Au) clusters (each with nominal 923 atoms), on amorphous Si3N4 substrate at room temperature, has been studied via time-resolved transmission electron microscopy (TEM). We found that the clusters approached each other in two stages. In the first stage, the drift velocity was independent of the particle separation and could be attributed to beam-induced random motion. In the second stage, the clusters were found to jump into contact with a much higher final averaged speed. This is independent of beam dose rates and is attributed to the van der Waal attraction

Pulse Shape Discrimination Techniques in Scintillating CsI(Tl) Crystals

There are recent interests with CsI(Tl) scintillating crystals for Dark Matter experiments. The key merit is the capability to differentiate nuclear recoil (nr) signatures from the background $\beta / \gamma$-events due to ambient radioactivity on the basis of their different pulse shapes. One of the major experimental challenges is to perform such pulse shape analysis in the statistics-limited domain where the light output is close to the detection threshold. Using data derived from measurements with low energy $\gamma$'s and nuclear recoils due to neutron elastic scatterings, it was verified that the pulse shapes between $\beta / \gamma$-events are different. Several methods of pulse shape discrimination are studied, and their relative merits are compared. Full digitization of the pulse shapes is crucial to achieve good discrimination. Advanced software techniques with mean time, neural network and likelihood ratios give rise to satisfactory performance, and are superior to the conventional Double Charge method commonly applied at higher energies. Pulse shape discrimination becomes effective starting at a light yield of about 20 photo-electrons. This corresponds to a detection threshold of about 5 keV electron-equivalence energy, or 40$-$50 keV recoil kinetic energy, in realistic experiments.Comment: 20 pages, 7 figure