No abstract

Natural fibre-based composites are replacing traditional materials in a wide range of structural applications that are used in different environments. Natural fibres suffer from thermal shocks, which affects the use of these composites in cold environment. Considering these, a goal was set in the present research to investigate the impact of cryogenic conditions on natural fibre composites. Composites were developed using polyester as matrix and jute-fibre and waste Teak saw-dust as reinforcement and filler, respectively. The effects of six parameters, viz., density of saw-dust, weight ratio of saw-dust, grade of woven-jute, number of jute layers, duration of cryogenic treatment of composite and duration of alkaline treatment of fibres on the mechanical properties of the composite was evaluated with an objective to maximise hardness, tensile, impact and flexural strengths. Taguchi method was used to design the experiments and response-surface methodology was used to model, predict and plot interactive surface plots. Results indicated that the duration of cryogenic treatment had a significant effect on mechanical properties, which was better only up to 60 min. The models were found to be statistically significant. The study concluded that saw-dust of density 300 kg/m3 used as a filler with a weight ratio of 13 wt.% and a reinforcement of a single layer of woven-jute-fibre mat of grade 250 gsm subjected to alkaline treatment for 4 h in a composite that has undergone 45 min of cryogenic treatment presented an improvement of 64% in impact strength, ca. 21% in flexural strength, ca. 158% in tensile strength and ca. 28% in hardness.

The linear stability of Walters B viscoelastic fluid-saturated horizontal porous layer is examined theoretically when the walls of the porous layer are subjected to time-periodic temperature modulation. Three types of boundary temperature modulations are considered namely, symmetric, asymmetric, and only the lower wall temperature is modulated while the upper wall is held at constant temperature. A regular perturbation method based on small amplitude of applied temperature field is used to compute the critical values of Rayleigh number and the corresponding wave number. The shift in critical Rayleigh number is calculated as a function of modulation frequency, viscoelastic parameter, and Prandtl number. The effect of all three types of modulations is found to be destabilizing as compared to the unmodulated system. This result is in contrast to the system with other types of fluids. Besides, the influence of physical parameters on the control of convective instability of the system is discussed.

The study was conducted to assess the effect of black pepper extract (BPE) supplementation on the growth performance, nutrient digestibility, fecal microbial, fecal gas emission, and meat quality of finishing pigs. A total of 180 crossbred [(Landrace × Yorkshire) × Duroc] finishing pigs with average initial body weight (BW) of 53.7 ± 1.42 kg were used in 10-week trial and allotted to 6 dietary treatments (6 replications pens/treatment with 5 pigs per pen). The dietary treatments were: CON (basal diet), TRT1-CON + 0.025% BPE, TRT2-CON + 0.05% BPE, TRT3-CON + 0.1% BPE, TRT4-CON + 0.2% BPE, TRT5-CON + 0.4% BPE. Linear increase in body weight gain (BWG) (p = 0.038, 0.006) and average daily gain (ADG) were observed (p = 0.035, 0.007,and 0.006 respectively), during the overall trial in pigs fed increasing levels of BPE in supplemented diet compared to control. The dietary supplementation of BPE showed a linear increase (p = 0.007) in gain-to-feed ratio (G:F) at week 10. However, there were no significant results observed on average daily feed intake (ADFI) during the overall experiment. The total tract digestibility of dry matter (DM) was linearly improved (p = 0.053) with graded levels of BPE. In addition, BPE diet supplementation had linearly increased fecal Lactobacillus counts (p = 0.048) and decreased Escherichia coli counts (p = 0.031) in pigs at week 10. Furthermore, NH3, methyl mercaptans, and acetic acid was linearly decreased (p = 0.023, 0.056, 0.054) in pigs fed graded level of BPE supplementation. The inclusion of BPE in pigs’ diet had linearly increased (p = 0.015) backfat thickness at week 10. Thus, we concluded that BPE supplementation had positively enhanced the growth performance, nutrient digestibility, fecal microbial, fecal gas emission, and meat quality of finishing pigs.

No abstract

Both linear and weakly nonlinear stability analyses are performed to study thermal convection in a rotating couple-stress fluid-saturated rigid porous layer. In the case of linear stability analysis, conditions for the occurrence of possible bifurcations are obtained. It is shown that Hopf bifurcation is possible due to Coriolis force, and it occurs at a lower value of the Rayleigh number at which the simple bifurcation occurs. In contrast to the nonrotating case, it is found that the couple-stress parameter plays a dual role in deciding the stability characteristics of the system, depending on the strength of rotation. Nonlinear stability analysis is carried out by constructing a set of coupled nonlinear ordinary differential equations using truncated representation of Fourier series. Sub-critical finite amplitude steady motions occur depending on the choice of physical parameters but at higher rotation rates oscillatory convection is found to be the preferred mode of instability. Besides, the stability of steady bifurcating equilibrium solution is discussed using modified perturbation theory. Heat transfer is calculated in terms of Nusselt number. Also, the transient behavior of the Nusselt number is investigated by solving the nonlinear differential equations numerically using the Runge-Kutta-Gill method. It is noted that increase in the value of Taylor number and the couple-stress parameter is to dampen the oscillations of Nusselt number and thereby to decrease the heat transfer.

A total of 40 crossbred weaned piglets (28 days old; [Landrace × Yorkshire] × Duroc) were used for preliminary assessment on potentials of Bacillus-based probiotics as an immune modulator in a Salmonella Typhimurium challenge model in a 3-week experiment. Pigs were randomly allotted to four experimental diets according to their initial body weight (9.21 ± 1.1 kg) and sex (10 pigs per treatment; 5 barrows and 5 gilts). The dietary treatments were basal diet (CON), basal diet + oral administration of Salmonella enterica ser. Typhimurium at the dosage of 1 mL containing 1 × 10 cfu/mL of viable cell concentrations at day 21 (SC), SC + Bacillus subtilis (BS), and SC+ Bacillus methylotrophicus (BM). After 12 h of Salmonella challenge, the red blood cell (RBC), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations were reduced (P < 0.05) whereas haptoglobin and cortisol levels were greater (P < 0.05) in SC compared with CON. However, the concentrations of RBC, IgG, and IgM were increased whereas haptoglobin and cortisol levels were reduced in BS and BM compared with SC. The probiotic-treated groups showed reduced (P < 0.05) IgM levels and increased (P < 0.05) WBC and cortisol levels compared with CON. The supplementation of probiotics showed increased (P < 0.05) fecal Lactobacillus counts and reduced Escherichia coli and Salmonella counts in piglets though there was no biological relevance compared with SC. Thus, in our preliminary study, Bacillus-based probiotic has shown some positive immunomodulatory effects in Salmonella-challenged pigs which provided a base for further studies.

The present study was conducted to evaluate the dietary effects of a marine red seaweed, Palmaria palmata, on the growth performance, blood profile, nutrient digestibility, meat quality, fecal gas emission, microbial population, and intestinal morphology of broilers. A total of 720 Ross 308 broiler chicks (1 day old), with an average body weight of 45 ± 0.50 g, were assigned to one of five dietary treatments (randomized complete block design) in a 42-day feeding trial. The five dietary treatments consisted of a basal diet (0% supplementation; control), and diets supplemented with 0.05%, 0.01%, 0.15%, or 0.25% red seaweed. Eight replicates were prepared per treatment, with each replicate consisting of 18 chicks in a cage. The results showed that there tended to be a greater increase in body weight in the seaweed-supplemented groups from day (d) 14 to 28 (p = 0.087) and d 28 to 42 (p = 0.082) compared to the control group, regardless of feed intake. Feed intake in the seaweed-supplemented groups increased linearly from d 14 to 28. A linear relationship between seaweed supplementation and the feed conversion ratio was observed from d 14 to 28 and throughout the whole experiment. The dietary inclusion of seaweed was linearly related to levels of albumin, creatinine, uric acid, and white blood cells in the broilers. Additionally, the total tract digestibility of dry matter increased linearly with an increase in seaweed supplementation. The dietary inclusion of seaweed had a beneficial effect on fecal microbes as Lactobacillus sp. counts increased and Escherichia coli and Salmonella sp. counts decreased on day 42. Histopathological examination of the intestine confirmed that seaweed dietary supplementation enhanced the heights and widths of the villi. Furthermore, the emission of fecal gases (NH3 and H2S) decreased linearly in broilers fed seaweed-supplemented diets. Dietary supplementation with seaweed led to improvements in meat quality traits, such as reductions in drip loss, water holding capacity, and cooking loss, as well as increases in relative organ weights. Based on these positive effects, dietary supplementation with seaweed in broilers can be considered a dietary option in poultry production.