• Asian-Australasian Journal of Animal Sciences
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• v.4 no.4
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• pp.399-405
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• 1991

The interaction of 4 dietary crude protein (13, 16, 19 or 22%) and 4 metabolizable energy (2600, 2800, 3000 or 3100 kcal ME/kg) levels on egg quality performances of Starcross layers were assessed between 245 and 275 days of age. The egg weight increased significantly with the increasing dietary protein and energy levels. But egg shape index, albumen index, yolk index, yolk dry matter, yolk protein, yolk fat, albumen protein and shell tickness were similar at all dietary protein and/or energy levels. The egg specific gravity and albumen weight increased but the yolk, weight, Haugh unit and albumen drymatter decreased with the increase of dietary protein levels and showed irregular trend with energy levels. The albumen dry matter and egg shell weight, however, were not affected by energy and protein levels. Simultaneous increase of protein and energy increased specific gravity, albumen index and shell thickness at a greater rate than that increased by the increase of protein or energy alone.

• The Korean Journal of Malacology
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• v.22 no.2
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• pp.143-150
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• 2006

The gonad index, condition index, reproductive cycle and spawning of the pen shell Atrina (Servatrina) pectinata were investigated using samples from the subtidal zone of Nokdo on the Boryeong coastal waters of Korea. Samples were collected monthly by SCUBA divers for one year from January to December, 2001. A. (Servatrina) pectinata is dioecious and oviparous. The spawning season of this species occurred once a year from June to August, with the main spawning occurring between June and July when the seawater temperature was around $20^{\circ}C$. Ripe oocytes were about 60-65 ${\mu}m$ in diameter. The reproductive cycle of this species could be classified into five successive stages; early active stage (November to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to August), and spent/inactive stage (August to October). Monthly changes in the gonad index reached a maximum (4.6) in May (ripe stage), thereafter, the GI values gradually decreased from June to August when spawning occurred continuously. Therefore, monthly changes in the GI values showed a similar pattern to the gonadal phase. The condition index (CI) of the meat part without the posterior adductor muscle reached the maximum in June (ripe and partially spawned stage) and the minimum in September (spent/inactive stage), Accordingly, monthly changes in the condition indice of the meat part without the posterior adductor muscle coincided with the gonadal phases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.453-459
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• 2000

This study was performed to investigate the effect of dietary crab shell powder on lipid metabolism in diet induced hyperlippidemic rats. Sixteen male Sprague-Dawley rats were divided into two groups and fed 20% (w/w) carb shell powder supplemented diet for 4 weeks. Energy intake and weight gain were lower in experimental group than in control group. Concentrations of plasma triglyceride, total cholesterol, LDL-cholesterol, and atherogenic index (AI) were decreased and concentration of HDL-cholesterol was increased by crab shell powder supplementation. Concentrations of liver total cholesterol and triglyceride were significantly lower in experimental group. The crab shell decreased triglyceride and cholesterol concentration in plasma and liver, and increased bile acid excretion in feces. Therefore, the crab shell powder is assumed to exhibit function of chitin or chitosan that effects on lipid metabolism and cholesterol reabsorption.

• The Korean Journal of Malacology
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• v.17 no.1
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• pp.13-18
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• 2001

The relationship between shell length and ring radius in each ring group was expressed as a regression line. Therefore, there is a correspondence in each ring formation. Based on the monthly variation of the marginal index (Ml') of the shell, it is assumed that the ring of this species was formed once a year during the period of August to October, and the main period of the annual ring formation was August through September. The relationship between shell length (SL) and total weight (TW) was expressed by the equation TW = 2.2476 $\times$ 10$^{-5}$ SL$^{3.536}$ ($r^2$= 0.90). Shell length (SL) and shell height (SH; mm) were highly correlated with the equation SH = 0.7545 SL - 0.0145 ($r^2$= 0.93). The shell length (SL)-shell width (SW) relation was expressed by the equation SW = 0.5336 SL- 2.4253 ($r^2$= 0.87). Growth curves for shell length and total weight fitted to the von Bertalanffy's equation were expressed as follows: SL$_{t}$ =60.02[1 - e$^{-0.6458(t-0.3895)}$ ], Twt = 43.63[1 - e$^{0.6458(t-0.3895)}$ ]$^{3.536}$ .

• Korean Journal of Poultry Science
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• v.14 no.2
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• pp.113-123
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• 1987

This study was carried out to investigate the effects of age of hen and oviposition time on egg weight, egg shell quality and e88 shape index in White Leghorn laying hens. The data were collected from 150 laying hens for about 4 months from September 1, 1986 to January 6, 1987. The results obtained from this study were summarized as follows; The percentage of the eggs produced before noon was decreased and that of the eggs produced after noon was increased as the hen gets older. Egg weight was increased rapidly to 270 days of age but after 270 days of age the rate of egg weight increase was slowly downed. The egg shell thickness became thinner and egg shell breaking strength was reduced and egg shape index was increased as the hen gets older. The egg weight was decreased as the oviposition time was proceeded and the regression coefficients of egg weight on oviposition time were -0.6788--0.4170, which means that the egg weight was decreased 0.4170-0.6788g per one hour delay of oviposition time. Egg shell thickness was increased 0. 0.00377-0.00643mm and egg shell breaking strength improved 0.0287-0.034kg/$\textrm{cm}^2$ per one hour delay of oviposition time. But it seems that there was no relationship between the oviposition time and the egg shape index.

• Structural Engineering and Mechanics
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• v.24 no.4
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• pp.447-461
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• 2006

Here, the axisymmetric free flexural vibrations and thermal stability behaviors of functionally graded spherical caps are investigated employing a three-noded axisymmetric curved shell element based on field consistency approach. The formulation is based on first-order shear deformation theory and it includes the in-plane and rotary inertia effects. The material properties are graded in the thickness direction according to the power-law distribution in terms of volume fractions of the constituents of the material. The effective material properties are evaluated using homogenization method. A detailed numerical study is carried out to bring out the effects of shell geometries, power law index of functionally graded material and base radius-to-thickness on the vibrations and buckling characteristics of spherical shells.

• Steel and Composite Structures
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• v.16 no.1
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• pp.77-96
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• 2014

In this paper, magneto-thermo-elastic problem of a thick truncated conical shell immersed in a uniform magnetic field and subjected to internal pressure is investigated. Material properties of the shell including the elastic modulus, magnetic permeability, coefficients of thermal expansion and conduction are assumed to be isotropic and graded through the thickness obeying the simple power law distribution, while the poison's ratio is assumed to be constant. The temperature distribution is assumed to be a function of the thickness direction. Governing equations of the truncated conical shell are derived in terms of components of displacement and thermal fields and discretised with the help of differential quadrature (DQ) method. Results are obtained for different values of power law index of material properties and effects of thermal load on displacement, stress, temperature and magnetic fields are studied. Results of the present method are compared with those of the finite element method.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.2
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• pp.341-347
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• 1992

Eggs used in this study were obtained from Saudi Arabian Baladi laying hens which were divided into four experimental groups and subjected to the following treatments: Commercial laying ration (17% CP, 3.6% Ca and 0.343%, available P) fed ad libitum as a control (C); Conventional force molting, feed removal for 10 days followed by 18 days full-feed of cracked corn (F); 15 days ad libitum intake of the control ration supplemented, to initiate forced-molt, with 0.35% aluminum as the sulfate (ALS) or the chloride (ALC). The hens were in production for 52 weeks and 17 months of age at the start of the trial and the post-treatment period lasted 36 weeks. During the treatment period F and AL treated groups had similar egg and shell weight, egg surface area, shell thickness and shell weight per unit of surface area but significantly (p<0.05) lower than the control. F had significantly (p<0.05) the highest and the control the lowest Haugh unit values whereas AL fed groups had significantly (p<0.05) lower meat spot incidence compared with the control which tended to have higher value than F group. ALC and F had significantly (p<0.05) the lowest yolk color grade whereas ALC had significantly (p<0.05) lower egg index than ALS and the control. During the post-treatment period the control had significantly (p<0.05) the highest egg index and blood spots incidence and ALS the lowest shell diensity compared with other groups. ALS had significantly (p<0.05) lower shell weight than ALC and the control whereas F and AL treated hens had significantly (p<0.05) the highest Haugh unit values and yolk color grades respectively. F had significantly (p<0.05) lower meat spots incidence than ALC and the control. The same results were observed for ALS compared with the control.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.1015-1019
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• 2003

A 50 day feeding trial was conducted with White Leghorn (WL) laying hens, 42 weeks old, to determine if feeding of varying levels of aflatoxin (AF), ochratoxin A (OA) or their combinations has any effect on their performance and egg quality parameters. Feeding of $T_4$, $T_7$, $T_8$, $T_9$ and $T_10$ caused significant reduction in feed intake of hens. Hen day egg productions were significantly reduced at all the levels of toxins except 0.5 ppm of AF. Maximum reduction in egg production was noticed at 2 and 4 ppm of AF and OA, respectively. Average body weight and egg weight were not affected by toxin feeding. The feed efficiency in terms of net feed efficiency and feed consumed per dozen egg produced was significantly reduced at higher levels of both the toxins and their combinations. Feed consumption for production of 1 kg egg mass remained uninfluenced due to aflatoxin feeding whereas significant increase in the value of the same was noticed at 4 ppm level of OA and combination of 1 and 2 ppm of AF and 2 and 4 ppm of OA ($T_9$ and $T_10$), respectively. Various levels of OA (1-4 ppm) and all the combination of two toxins ($T_8$, $T_9$ and $T_10$) significantly altered the shape index of eggs in laying hens. The shell thickness was significantly reduced by higher level of AF (2 ppm), OA (2 and 4 ppm) and their combination. Albumen index, Haugh Unit and yolk index remained unchanged due to incorporation of toxins in the diet. It is concluded that AF, OA either singly or in combination at higher levels could depress the performance in terms of egg production and feed efficiency significantly. The egg quality parameters i.e. shape index and shell thickness were also significantly affected.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.71-78
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• 2001

Age and growth of the pen shell, Atrina (Servatrina) pectinata japonica, on the west coast of Korea were studied based on 701 samples caught in April 1995 to March 1996. The results are summarized as follows: the relationship between shell height and ring radius in each ring group was expressed as a regression line. Therefore, it could be recognized that there is a correspondence in the formation of each ring. Based on the monthly variation of the marginal index (MI') of the shell, it was assumed that the ring of this species was formed once a year during the period of June to July. The relationship between shell height (SH) and total weight (TW) were expressed by the following equation TW = 5.906$\times$10/$^{-3}$SH$^{3.844}$. Shell length (SL) and shell height were highly correlated according to the following equation SL = 0.5277 SH +0.0934. The shell height-shell width (SW) relation was expressed by the following equation SW = 0.2681 SH -1.3757. Growth curves for shell height and total weight fitted to the von Bertalanffy's equation were expressed as: SHt=30.99(1-e-$^{-0.3212(t+0.9653)}$, TWt=657.94(1-e-$^{-0.3212(t+0.9653}$)$^{3.3844}$.