The straining behavior of the shape memory alloy (SMA) fibers-reinforced mortar was investigated in this study by the monotonic compressive and cyclic compressive tests. Two types of SMA fibers with ...a crimped and dog-bone shape were used due to the high pullout resistance capacity, which guaranteed that the fibers and mortar matrix were composited well. The plain mortar was mixed with two different compositions to create the higher elastic modulus mortar matrix and the lower elastic modulus mortar matrix compared with the elastic modulus of SMA fibers. The results of the experimental test indicated that the non-heated SMA fibers could control the strains in both elastic and plastic phases; in which, the crimped fiber was more effective in precracking due to the higher composite capacity while the dog-bone-shaped fiber had a higher effect in post-cracking. After heating, the dog-bone-shaped fiber slipped more than that of the crimped fiber; thus, the heated crimped fiber was more effective than the heated dog-bone-shaped fiber in controlling strains after cracking. The effect of SMA fibers on the elastic modulus depended on both the elastic modulus of mortar matrix and the property of SMA fibers. In the plastic phase, the fibers were effective on reducing the speed of damage in monotonic case. An equation using reinforcing index was suggested for damage evolution in the cyclic case.
A form-finding method of tensegrity systems is a process of finding an equilibrium configuration and a key step in the design of tensegrity. Over the past few years, several studies have been made on ...the form-finding methods of tensegrity systems, however, these methods are limited in the tensegrity systems with multiple self-stress states. In this study, a numerical method is presented for form-finding of tensegrity structures with multiple states of self-stress by using a force density method combined with a genetic algorithm. The proposed method can design the desired tensegrity shape through a genetic algorithm with appropriate constraints. The design variable can be uniquely defined in the case of multiple states of self-stress using only the constraint of the member types. An eigenvalue decomposition of the force density matrix and a singular value decomposition of the equilibrium matrix are performed repeatedly in order to determine a feasible solution for nodal coordinates and force densities. A genetic algorithm is then adopted to uniquely define a single integral feasible set of force densities. Several numerical examples are presented to prove efficiency in searching for self-equilibrium configurations of tensegrity structures. In all cases, the single integral feasible self-stress states can be obtained.
An improved shear strength equation is proposed that considers transverse reinforcement spacing and support conditions for concrete wide beams. Eighteen specimens were fabricated to examine the ...influence of transverse reinforcement spacing, the number of transverse shear reinforcement, and support width on shear capacity. From the test results, a shear strength equation is proposed and used to evaluate the shear strength of 23 specimens from previous studies and 18 from this study. For the 41 specimens, the proposed shear strength equation results had a mean of 1.16 and a standard deviation of 0.16. It showed that the proposed shear strength equation can predict shear strength reasonably well for concrete wide beams.
Dietary yeast cell wall products (YCW) are recognized as a feed additive due to multifunctional benefits by the biological response modulators. Thus, this study was conducted to verify a potential ...advantage of YCW for improving growth performance, nutrient digestibility, immune responses, and intestinal health and microbiota of weaned pigs. A total of 112 weaned pigs (7.99 ± 1.10 kg of body weight; 28 days old) were arbitrarily allocated to two experimental treatments with eight pigs (four barrows and four gilts) per pen and seven replicate pens per treatment in a completely randomized block design (block = BW and sex): (1) a basal diet based on corn and soybean meal (CON) and (2) CON + 0.05% YCW. The experimental period was for 4 weeks. There were no differences in final body weight, average daily feed intake, and gain-to-feed ratio between dietary treatments. In contrast, pigs fed YCW had higher average daily gain (p = 0.088) and apparent ileal digestibility of DM (p < 0.05) and energy (p = 0.052) and lower diarrhea frequency (p = 0.083) than those fed control diet (CON). Pigs fed YCW also had a higher (p < 0.05) ratio between villus height and crypt depth, villus width and area, and goblet cell counts in the duodenum and/or jejunum than those fed CON. Dietary YCW decreased (p < 0.05) serum TNF-α and IL–1β of weaned pigs on day 7 and 14, respectively, compared with CON. Furthermore, pigs fed YCW had higher (p < 0.05) ileal gene expression of claudin family, occludin, MUC1, INF-γ, and IL-6 and lower (p < 0.05) that of TNF-α than those fed CON. Lastly, there were no differences in the relative abundance of bacteria at the phylum level between CON and YCW. However, dietary YCW increased (p < 0.05) the relative abundance of genera Prevotella and Roseburia compared with CON. This study provided that dietary YCW improved growth rate, nutritional digestibility, and intestinal health and modified immune responses and intestinal microbiota of weaned pigs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This experiment was performed to verify whether dietary heat-killed
Lactobacillus rhamnosus
(LR) improves growth performance
and modulates immune responses of weaned pigs. Ninety-six weaned pigs ...(Landrace
× Yorkshire × Duroc; 6.95 ± 0.25 kg body weight BW; 28 d
old) were randomly allocated to four treatments: 1) a basal diet without
heat-killed LR (CON), 2) T1 (CON with 0.1% heat-killed LR), 3) T2 (CON with 0.2%
heat-killed LR), and 4) T3 (CON with 0.4% heat-killed LR). Each treatment had
six pens with four pigs (6 replicates per treatment) in a randomized completely
block design. The heat-killed LR used in this study contained 1 ×
10
9
FU/g of LR in a commercial product. Pigs were fed each
treatment for four weeks using a two-phase feeding program to measure growth
performance and frequency of diarrhea. During the last week of this study, all
diets contained 0.2% chromic oxide as an indigestible marker. Fecal sampling was
performed through rectal palpation for the consecutive three days after the four
adaptation days to measure apparent total tract digestibility (ATTD) of dry
matter, crude protein, and gross energy (GE). Blood sampling was also performed
on day 1, 3, 7, and 14 after weaning to measure immune responses such as serum
tumor necrosis factor-α (TNF-α), transforming growth
factor-β1 (TGF-β1), C-reactive protein (CRP), and cortisol. The
heat-killed LR increased (
p
< 0.05) growth rate, feed
efficiency, and ATTD of GE for overall experimental period compared with CON,
but reduced (
p
< 0.05) post-weaning diarrhea. In
addition, pigs fed diets contained heat-killed had lower concentrations of serum
TNF-α (d 7;
p
< 0.05), TGF-β1 (d 7;
p
< 0.10), and cortisol (d 3 and 7;
p
< 0.05) than pigs fed CON. In conclusion, dietary
heat-killed LR improved growth rate, modified immune responses of weaned pigs,
and alleviated post-weaning diarrhea.
Surrogate modeling techniques are widely employed in solving constrained expensive black-box optimization problems. Therein, Kriging is among the most popular surrogates in which the trend function ...is considered as a constant mean. However, it also encounters several challenges related to capturing the overall trend with a relatively limited number of function evaluations as well as searching feasible points with complex or discontinuous feasible regions. To address this above issue, this paper presents an improved surrogate blind Kriging (IBK) and a combined infill strategy to find the optimal solution. According to enhancing the prediction accuracy of metamodels of objective and constraints, the high-order effects of regression function in the blind Kriging are identified by promising a variable selection technique. In addition, an infill strategy is developed based on the probability of feasibility, penalization, and constrained expected improvement for updating blind Kriging metamodels of the objective and constraints. At each iteration, two infill sample points are allocated at the positions to achieve improvement in optimality and feasibility. The IBK metamodels are updated by the newly-added infill sample points, which leads the proposed framework search to rapidly converge to the optimal solution. The performance and applicability of the proposed model are tested on several numerical benchmark problems via comparing with other metamodel-based constrained optimization methods. The obtained results indicate that IBK generally has a greater efficiency performance and outperforms the competitors in terms of a limited number of function evaluations. Finally, IBK is successfully applied to structural design optimization. The optimization results show that IBK is able to find the best feasible design with fewer evaluation functions compared with other studies, and this demonstrates the effectiveness and practicality of the proposed model for solving the constrained expensive black-box engineering design optimization problems.
This study was conducted to evaluate effects of dietary protease (PR) on growth performance, nutrient digestibility, and intestinal morphology of weaned pigs. A total of 75 weaned pigs 7.06 ± 0.18 kg ...of average body weight (BW); 28 day old were randomly allotted to 3 dietary treatments in a randomized complete block design (blocks = BW and sex): a diet based on corn and soybean meal to meet the requirement of crude protein (CP) as a positive control (PC; CP = 24.49%), a low protein diet as a negative control (NC; CP = 22.51%), and NC + 0.02% PR. The PR used in this study was a commercial product containing 75,000 protease units/g derived from
produced in
Pigs were fed the dietary treatments for 6 weeks and the diets containing 0.2% chromic oxide for the last week of this study. Blood, feces, ileal digesta, and ileum samples were collected from randomly selected two pigs in each pen on respective time points. Measurements were growth performance, apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of dry matter (DM), CP, and energy, frequency of diarrhea, packed cell volume (PCV), and ileal morphology of weaned pigs. Pigs fed PC and PR had higher (
< 0.05) final BW, average daily gain (ADG), and gain to feed ratio (G:F) during overall experimental period than those fed NC. Pigs fed PC and PR had higher (
< 0.05) AID or ATTD of DM, CP, or energy than those fed NC. Moreover, pigs fed PR had higher ratio between villus height and crypt depth (
< 0.05) and number of goblet cells (
< 0.05) than those fed NC. Addition of PR decreased (
< 0.05) frequency of diarrhea for the first two weeks after weaning compared with PC and NC. In addition, pigs fed PR had lower (
< 0.05) PCV on d 14 after weaning than those fed PC and NC. In conclusion, addition of PR in nursery diets with a low protein level significantly improved growth performance, nutrient digestibility, and intestinal morphology of weaned pigs.
Dietary glutamic acid (GLU) is used as a feed additive because of its functional characteristics that may affect the growth performance and health of pigs. This study was carried out to determine the ...effects of dietary GLU on growth performance, nutrient digestibility, immune responses, and intestinal health of weaned pigs. A total of ninety-six weaned pigs (8.07 ± 1.17 kg of body weight; 28 days of age) were assigned to two dietary treatments (8 pigs/pen; 6 replicates/treatment) in a randomized complete block design (block: body weight): (1) a typical weaner diet (CON) and (2) CON supplemented with 0.5% GLU. The experimental period was for 4 weeks. All data and sample collections were performed at the specific time points during the experimental period. Pigs fed GLU had higher average daily gain and average daily feed intake for the first two weeks and nutrient digestibility than pigs fed CON. In addition, dietary GLU increased villus height to crypt depth ratio, number of goblet cells, and ileal gene expression of claudin family and occludin compared with CON, but decreased serum TNF-α and IL-6 and ileal gene expression of TNF-α. Moreover, pigs fed GLU had increased relative composition of bacterial communities of genus
and
and decreased genus
and
compared with those fed CON. This study suggests that dietary GLU influences growth performance and health of weaned pigs by modulating nutrient digestibility, intestinal morphology, ileal gene expression of tight junction proteins and cytokines, immune responses, and microbial community in the gut.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This article is firstly concerned with bending and free vibration analyses of in-plane bi-directional functionally graded (IBFG) plates with variable thickness in the framework of isogeometric ...analysis (IGA). The plate thickness is smoothly altered in both x- and y-axes by a predetermined power law. Two types of power-law material models with the symmetrical and asymmetrical volume fraction distribution are suggested to characterize the in-plane material inhomogeneity. A non-uniform rational B-spline (NURBS) surface for simultaneously representing both variable thickness and volume fraction distribution of each constituent is employed. By using the k-refinement strategy, the C0-continuous requirement at symmetrical material interfaces can be achieved, yet still ensuring material gradations elsewhere owing to the prominent advantage of NURBS basis functions in easily controlling continuity. Effective material properties are then evaluated by either the rule of mixture or the Mori-Tanaka scheme. An analysis NURBS surface separately created with the foregoing NURBS surface is utilized to exactly describe geometry and approximately solve unknown solutions in finite element analysis (FEA) based on the IGA associated with a generalized shear deformation theory (GSDT). The Galerkin C1-continuous isogeometric finite element model is therefore simply achieved due to the possibility of flexibly meeting high-order derivatives and continuity of analysis NURBS functions. In addition, no shear correction factors exist in the present formulation, although shear deformation effects are still considered. The influences of variable thickness, material property, length-to-thickness ratio, boundary condition on bending and free vibration responses are investigated and discussed in detail through several numerical examples.
This experiment was performed to verify whether dietary heat-killed Lactobacillus rhamnosus (LR) improves growth performance and modulates immune responses of weaned pigs. Ninety-six weaned pigs ...(Landrace × Yorkshire × Duroc; 6.95 ± 0.25 kg body weight BW; 28 d old) were randomly allocated to four treatments: 1) a basal diet without heat-killed LR (CON), 2) T1 (CON with 0.1% heat-killed LR), 3) T2 (CON with 0.2% heat-killed LR), and 4) T3 (CON with 0.4% heat-killed LR). Each treatment had six pens with four pigs (6 replicates per treatment) in a randomized completely block design. The heat-killed LR used in this study contained 1 × 109 FU/g of LR in a commercial product. Pigs were fed each treatment for four weeks using a two-phase feeding program to measure growth performance and frequency of diarrhea. During the last week of this study, all diets contained 0.2% chromic oxide as an indigestible marker. Fecal sampling was performed through rectal palpation for the consecutive three days after the four adaptation days to measure apparent total tract digestibility (ATTD) of dry matter, crude protein, and gross energy (GE). Blood sampling was also performed on day 1, 3, 7, and 14 after weaning to measure immune responses such as serum tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), C-reactive protein (CRP), and cortisol. The heat-killed LR increased (p < 0.05) growth rate, feed efficiency, and ATTD of GE for overall experimental period compared with CON, but reduced (p < 0.05) post-weaning diarrhea. In addition, pigs fed diets contained heat-killed had lower concentrations of serum TNF-α (d 7; p < 0.05), TGF-β1 (d 7; p < 0.10), and cortisol (d 3 and 7; p < 0.05) than pigs fed CON. In conclusion, dietary heat-killed LR improved growth rate, modified immune responses of weaned pigs, and alleviated post-weaning diarrhea.
PDF
