Biomechanical behaviour and hyperelastic model parameters identification of sheep omasum

Abstract The function of the omasum is incompletely understood; however, the omasum plays an important role in the transport of appropriately sized feed particles from the reticulorumen to the abomasum, oesophageal groove closure, fermentation of ingesta, and absorption of water, volatile fatty acids, and minerals. The aim of this study is to evaluate the suitable hyperelastic anisotropic model based on biomechanical properties of sheep omasum. The results show that all five (5) hyperelastic models may be suitable for the evaluation of sheep omasum. The average coefficient of determination (R2) of Fung, Polynomial (Anisotropic), Holzapfel (2000), Holzapfel (2005) and Four-Fiber-Family hyperelastic models were found to be 0.79 ± 0.19, 0.95 ± 0.05, 0.92 ± 0.07, 0.93 ± 0.05 and 0.94 ± 0.03, respectively. Also, it was found that the best hyperelastic model for fitting uniaxial data of the sheep omasum was Polynomial (Anisotropic) with EI of 100.0 followed by the Four-Fiber-Family model with EI of 96.18.

Download Full-text

Optimizing the impact of temperature on bio-hydrogen production from food waste and its derivatives under no pH control using statistical modelling

Biogeosciences ◽

10.5194/bg-12-6503-2015 ◽

2015 ◽

Vol 12 (21) ◽

pp. 6503-6514 ◽

Cited By ~ 10

Author(s):

C. Arslan ◽

A. Sattar ◽

C. Ji ◽

S. Sattar ◽

K. Yousaf ◽

...

Keyword(s):

Fatty Acids ◽

Hydrogen Production ◽

Food Waste ◽

Volatile Fatty Acids ◽

Negative Impact ◽

Glucose Consumption ◽

Statistical Modelling ◽

Effect Of Temperature ◽

Coefficient Of Determination ◽

The Impact

Abstract. The effect of temperature on bio-hydrogen production by co-digestion of sewerage sludge with food waste and its two derivatives, i.e. noodle waste and rice waste, was investigated by statistical modelling. Experimental results showed that increasing temperature from mesophilic (37 °C) to thermophilic (55 °C) was an effective mean for increasing bio-hydrogen production from food waste and noodle waste, but it caused a negative impact on bio-hydrogen production from rice waste. The maximum cumulative bio-hydrogen production of 650 mL was obtained from noodle waste under thermophilic temperature condition. Most of the production was observed during the first 48 h of incubation, which continued until 72 h of incubation. The decline in pH during this interval was 4.3 and 4.4 from a starting value of 7 under mesophilic and thermophilic conditions, respectively. Most of the glucose consumption was also observed during 72 h of incubation and the maximum consumption was observed during the first 24 h, which was the same duration where the maximum pH drop occurred. The maximum hydrogen yields of 82.47 mL VS−1, 131.38 mL COD−1, and 44.90 mL glucose−1 were obtained from thermophilic food waste, thermophilic noodle waste and mesophilic rice waste, respectively. The production of volatile fatty acids increased with an increase in time and temperature in food waste and noodle waste reactors whereas they decreased with temperature in rice waste reactors. The statistical modelling returned good results with high values of coefficient of determination (R2) for each waste type and 3-D response surface plots developed by using models developed. These plots developed a better understanding regarding the impact of temperature and incubation time on bio-hydrogen production trend, glucose consumption during incubation and volatile fatty acids production.

Download Full-text

Hyperelastic Material Model Selection of Structural Silicone Sealants for Use in Finite Element Modeling

Volume 1: 37th Computers and Information in Engineering Conference ◽

10.1115/detc2017-67589 ◽

2017 ◽

Author(s):

Larry D. Carbary ◽

Jon H. Kimberlain ◽

John C. Oliva

Keyword(s):

Finite Element ◽

Material Model ◽

Hyperelastic Material ◽

Model Parameters ◽

Element Analysis ◽

Structural Silicone ◽

Lab Experiments ◽

Hyperelastic Model ◽

Hyperelastic Models ◽

Selection Of

Hyperelastic material model parameters have been developed to capture the behavior of silicone based construction sealants. Modern commercially available finite element analysis software makes it quite accessible to develop hyperelastic material models, automating the process of curve-fitting experimental lab data to specific hyperelastic formulations. However, the process of selecting a particular hyperelastic model from those supported is not straightforward. Here, a series of lab experiments are employed to guide the selection of the hyperelastic model that best describes various structural silicone glazings. A total of 10 different sealants are characterized with discussion of variations among the models. Comparisons of the best performing hyperelastic models for the different sealants are presented. Finally, an application is described in which these hyperelastic models have begun to be implemented in practice.

Download Full-text

An Unstructured Model for Anaerobic Treatment of Raw Cheese Whey for Volatile Fatty Acids Production

Energies ◽

10.3390/en13071850 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1850

Author(s):

Claudio B-Arroyo ◽

Antonio Lara-Musule ◽

Ervin Alvarez-Sanchez ◽

Gloria Trejo-Aguilar ◽

Juan-Rodrigo Bastidas-Oyanedel ◽

...

Keyword(s):

Fatty Acids ◽

Dynamic Behavior ◽

Volatile Fatty Acids ◽

Cheese Whey ◽

Value Added ◽

Anaerobic Treatment ◽

Operating Conditions ◽

Model Parameters ◽

Temperature Conditions ◽

Proposed Model

The whey is a byproduct of the dairy industry that, if not treated properly, can cause serious environmental pollution problems. Anaerobic treatment is an alternative for its recovery, since, in addition to reducing the organic load. it allows the generation of value-added products such as volatile fatty acids (VFA) and biogas. However, the process is very complex and requires specific operating conditions that guarantee its stability and favor the production of value-added compounds. In this work, an unstructured mathematical model is proposed to evaluate the dynamic behavior of the stages of the anaerobic degradation process of the whey (i.e., hydrolysis, acidogenesis, acetogenesis and methanogenesis). The proposed model considers the dynamic variation in pH during the experiment. To validate the model, an experimental set was carried out at pH and temperature conditions that favor the production of VFAs. Experimental results show that the anaerobic treatment of the raw cheese whey favors pH = 5.5; for T = 40 °C, the maximum VFA production is obtained (30.71 gCOD L−1), and for T = 35 °C, a 45.81% COD degradation is reached. The proposed model considers the effect of pH and temperature and it is validated in the region where the experimental tests were carried out. The model parameters were estimated using the Levenberg–Marquardt method, obtaining coefficients of determination R2 > 0.94. The proposed model can describe the dynamic behavior of the key variables in the anaerobic treatment of raw cheese whey at different pH and temperature conditions, finding that VFA production is favored at pH ≥ 7, while the highest COD removal results in acidic conditions

Download Full-text

Understanding regional mechanics of rat myocardia by fitting hyperelatsic models

10.21203/rs.3.rs-957393/v1 ◽

2021 ◽

Author(s):

Fulufhelo Nemavhola ◽

Harry Ngwangwa ◽

Thanyani Pandelani ◽

Neil Davies ◽

Thomas Franz

Keyword(s):

Rat Heart ◽

Goodness Of Fit ◽

Regional Difference ◽

Computational Models ◽

Coefficient Of Determination ◽

Myocardial Tissue ◽

Biaxial Test ◽

Anisotropic Model ◽

Septal Wall ◽

Hyperelastic Model

Abstract Availability of biaxial mechanical data for heart myocardia remains high in demand for the development of accurate and detailed computational models. The aim of this study is to study the regional difference of wall mechanics using rat heart in the left ventricle (LV), septal wall (STW) and right ventricle (RV). This was achieved by conducting a biaxial test on three rat heart myocardia (i.e LV, RV and STW). Fung, Choi-Vito, Polynomial (Anistropic), Four-Fiber family, Holzapfel (2000) and Holzapfel (2005) hyperelastic models were selected and fitted on the bixial data of the LV, RV and STW. The best hyperelastic model was the selected based on evaluation index (EI) determined from the coefficient of determination (R2). All the six models were then compared in all three rat heart myocardia. The results show that the Polynomial (Anisotropic) model outperforms the other five models in all myocardial tissues with EI’s above 90 % goodness of fit. The Four-fiber-family and the two Holzapfel models perform equally in the LV and STW myocardial tissue between 50 and 70 % goodness of fit. The Fung and Choi-Vito models yielded poor goodness of fit in the LV and STW myocardial tissues. Parameter fitting is useful method in advancing reliable data to be used in the development of accurate computational models.

Download Full-text

Unravelling a microbial synergy to boost caproate production via carboxylates chain elongation with ethanol

HKIE Transactions ◽

10.33430/v26n2thie-2018-0041 ◽

2019 ◽

Vol 26 (2) ◽

pp. 63-71

Author(s):

Ling Leng ◽

Ying Wang ◽

Peixian Yang ◽

Takashi Narihiro ◽

Masaru Konishi Nobu ◽

...

Keyword(s):

Fatty Acids ◽

Volatile Fatty Acids ◽

Microbial Consortia ◽

Chain Elongation ◽

Desulfovibrio Vulgaris ◽

Rrna Gene ◽

Selective Enrichment ◽

Microbial Network ◽

Cost Efficient ◽

Rrna Gene Sequencing

Chain elongation of volatile fatty acids for medium chain fatty acids production (e.g. caproate) is an attractive approach to treat wastewater anaerobically and recover resource simultaneously. Undefined microbial consortia can be tailored to achieve chain elongation process with selective enrichment from anaerobic digestion sludge, which has advantages over pure culture approach for cost-efficient application. Whilst the metabolic pathway of the dominant caproate producer, Clostridium kluyveri, has been annotated, the role of other coexisting abundant microbiomes remained unclear. To this end, an ethanol-acetate fermentation inoculated with fresh digestion sludge at optimal conditions was conducted. Also, physiological study, thermodynamics and 16 S rRNA gene sequencing to elucidate the biological process by linking the system performance and dominant microbiomes were integrated. Results revealed a possible synergistic network in which C. kluyveri and three co-dominant species, Desulfovibrio vulgaris, Fusobacterium varium and Acetoanaerobium sticklandii coexisted. D. vulgaris and A. sticklandii (F. varium) were likely to boost the carboxylates chain elongation by stimulating ethanol oxidation and butyrate production through a syntrophic partnership with hydrogen (H2) serving as an electron messenger. This study unveils a synergistic microbial network to boost caproate production in mixed culture carboxylates chain elongation.

Download Full-text

МЕТАБОЛИТЫ ПРОБИОТИЧЕСКИХ БАКТЕРИЙ ОТВЕЧАЮТ ЗА ЭФФЕКТИВНОСТЬ ДЕЙСТВИЯ ПРОБИОТИКА "ПРОФОРТ®"

10.33845/0033-3239-2019-68-9-10-45-47 ◽

2019 ◽

Keyword(s):

Fatty Acids ◽

Volatile Fatty Acids ◽

Broiler Chicks ◽

Bacillus Sp

МЕЛИКИДИ В.Х., ТЮРИНА Д.Г., СЕЛИВАНОВ Д.Г., НОВИКОВА Н.И. ООО «БИОТРОФ», Санкт-Петербург Аннотация: Приведены данные исследования методом газожидкостной хроматомасс-спектрометрии метаболитов, синтезируемых пробиотическими бактериями, входящими в состав кормовой добавки «Профорт®». Проведен опыт в условиях интенсивного промышленного птицеводства по применению кормовой добавки «Профорт®» (50 тыс. голов бройлеров в группе). Среди метаболитов пробиотических штаммов Enterococcus sp. и Bacillus sp. обнаружены такие полезные вещества, как молочная кислота, уксусная, пропионовая и другие короткоцепочечные (летучие) жирные кислоты, активные пептиды. Результаты зоотехнического опыта показали, что при скармливании бройлерам пробиотика «Профорт®» (500 г/т) живая масса при убое в 40 дней была выше контроля на 6,9%, конверсия корма улучшилась на 3,0%, а европейский индекс продуктивности бройлеров - на 5,69%. Ключевые слова: ПРОБИОТИКИ, МЕТАБОЛИТЫ, ЛЕТУЧИЕ ЖИРНЫЕ КИСЛОТЫ, ЦЫПЛЯТА-БРОЙЛЕРЫ,ПРОДУКТИВНОСТЬ, PROBIOTICS, METABOLITES, VOLATILE FATTY ACIDS, BROILER CHICKS,PRODUCTIVITY

Download Full-text