• Asian-Australasian Journal of Animal Sciences
• /
• 제5권3호
• /
• pp.541-544
• /
• 1992

Duck eggs from Indigenous (desi), Khaki Campbell and Crossbred (Indian Runner $\times$ Khaki Campbell, $F_1$) were incubated to investigate fertility, hatchability and other related traits. The fertility was highest in crossbred followed by Khaki Campbell and Indigenous ducks respectively. The embryonic mortality was highest in Khaki Campbell followed by Indigenous and crossbred respectively. The embryonic mortality was higher in eggs of 7 days pre-incubation holding period and lower in eggs of 3 days pre-incubation holding period. A significant positive correlation was found between temperature and embryonic mortality as well as relative humidity and embryonic mortality. The hatchability on fertile eggs was highest in crossbred ducks and almost similar in both Khaki Campbell and Indigenous ducks. The hatchability was higher in eggs stored for 3 days in comparison with that of 7 days pre-incubation holding period. A negative correlation was found between temperature and hatchability as well as humidity and hatchability. The normal ducklings hatched out from the eggs of Khaki Campbell ducks was highest followed by Indigenous and crossbred respectively. There was a negative correlation between temperature and normal ducklings hatched as well as relative humidity and normal ducklings hatched. The preincubation holding temperature and relative humidity had positive correlation with dead-in-shell.

• Asian-Australasian Journal of Animal Sciences
• /
• 제7권4호
• /
• pp.499-503
• /
• 1994

One thousand and eighty eggs of Japanese quail (Coturnix coturnix Japonica) were set into the incubator maintaining 36 treatment groups (3 egg weight groups ${\times}3$ seasons ${\times}4$ preincubation holding periods) to evaluate their hatchability performances. Holding periods had significant (p<0.05) effect on hatchability and the seasons showed significant (p<0.05) effect on chick weight. All the parameters (except fertility) were significantly (p<0.01) influenced by the egg weight. None of the parameters maintained regular trend with egg weight and pre-incubation holding periods. Significant interactions were not observed on any of the parameters (except fertility) studied. The egg weight maintained significant (p<0.05) negative correlation with fertility and positive correlation with chick weight. Eggs of medium weight (9.10 to 10.00 cm) could be hatched satisfactorily between 4 and 7 days of pre-incubation holding periods in any season of the year.

• Asian-Australasian Journal of Animal Sciences
• /
• 제23권2호
• /
• pp.240-245
• /
• 2010

The effects of controlled energy restriction and duration of pre-incubation egg holding on fertility, hatchability and hatch losses were evaluated in aged broiler breeders (64 wk). The energy (ME) required for maintenance, activity, growth and anticipated egg production was calculated and offered to a control group (283-471 kcal/kg) from 21-64 weeks of age. In three other groups, ME was quantitatively reduced either by 20% (SER; severe energy restriction) or 10% (MER; moderate energy restriction) and increased by10% (EEF; excess energy feeding) over the control group (CER; controlled energy restriction). Each diet was offered to 130 pullets in individual cages, and the quantity of ME increased with age. At the end of 64 weeks, fertile eggs were collected from each dietary group for 11 consecutive days and grouped under 4 holding periods based on the length of storage (2, 5, 8 or 11 d). The influence of energy regimes, egg holding intervals and their interaction was evaluated on fertility, hatch losses and hatchability. Broiler breeders maintained on SER regime (231-419 kcal/d) produced maximum number of eggs (993) followed by MER (819), CER (624) and EEF (438) during the 11-day period. The percent fertility and hatchability was significantly (p$\leq$0.05) higher in SER and MER groups compared to CER and EEF. However, energy regimes did not influence the loss in egg weight during pre-incubation storage, shell weight, shell thickness or hatch losses as dead germs and dead in shell. The improvement in hatchability in SER and MER groups appeared to be closely related to higher fertility and lower embryonic mortality. Holding of eggs for 11 days showed a linear loss in egg weight with the length of storage, but did not influence the fertility and hatch losses. The percent hatchability on eggs set was maximum when storage period was restricted to 5 days. The interaction between energy regimes and egg holding periods exhibited better hatchability results with SER regime when eggs were held for 5 days. Response to MER was not different from SER. It was obvious that energy restriction during production period had a positive influence on egg number, fertility and hatchability in aged breeders. At 64 weeks of age, holding of fertile eggs for 5 days prior to incubation was adequate for optimum hatchability in breeders.

• Journal of Industrial and Engineering Chemistry
• /
• 제67권
• /
• pp.358-364
• /
• 2018

An isotropic pitch precursor for fabricating carbon fibres was prepared by co-carbonization of ethylene bottom oil(EBO) and polyvinyl chloride (PVC). Various pre-treatments of EBO and PVC, and a high heating rate of $3^{\circ}C/min$ with no holding time, were evaluated for their effects on the oxidative stabilization process and the mechanical stability of the resulting fibres. Our stabilization process enhanced the volatilization, oxidative reaction and decomposition properties of the precursor pitch, while the addition of PVC both decreased the onset time and accelerated the oxidative reaction. Aliphatic carbon groups played a critical role in stabilization. Microstructural characterization indicated that these were first oxidised to carbon-oxygen single bonds and then converted to carbon-oxygen double bonds. Due to the higher heating rate and lack of a holding step during processing,the resulting thermoplastic fibers did not completely convert to thermoset materials, allowing partially melted, adjacent fibres to fuse. Fiber surfaces were smooth and homogeneous. Of the various methods evaluated herein, carbon fibers derived from pressure-treated EBO and PVC exhibited the highest tensile strength. This work shows that enhancing the naphthenic component of a pitch precursor through the co-carbonization of pre-treated EBO with PVC improves the oxidative properties of the resulting carbon fibers.

• 한국가금학회지
• /
• 제29권2호
• /
• pp.89-94
• /
• 2002

본 연구는 육용종계 종란의 보관조건에 따른 입란전 보관 기간이 부화율에 미치는 영향을 구명하고자 실시하였다. 산란 후 입란전 종란보관기간을 달리한 7개 처리, 즉 1일 보관 (T1)에서부터 7일 보관(T7)으로 시험을 실시하였다. 각 처리당3개의 반복을 두어 반복당40개의 종란을 공시하였다. 본 연구는 종계의 주령이 40주령인 여름과 50주령인 가을에 실시하였다. 저장온도에 따른 입란전 종란의 저장기간동안 발육후 18일째의 입란대비 감량률, 수정률, 부화율 및 발육중배자 사망률을 조사하였다. 시험결과 종계의 주령이 40주령인 여름철에는 보관기간이 길어짐에 따라 부화율이 급격하게 하락하여 3일 이상 보관시에는 1~2일 보관보다 낮아 통계적 유의차가 인정되었다(P<.05). 종계의 주령이 50주령인 가을철에는 보관기간에 따른 부화율의 차이는 인정되지 않았다(P<.05). 결론적으로 외기 환경온도가 높을 때(여름철, 25 $25^{\circ}C$이상) 3일 이상의 종란보관은 부화율에 큰 영향을 미치며, 1주일 이상 보관시 부화율 저하를 방지하기 위해서는 13~$19^{\circ}C$의 온도에 보관하는 것이 바람직함을 입증하였다.

• Journal of Ecology and Environment
• /
• 제35권1호
• /
• pp.1-7
• /
• 2012

To calculate and predict soil carbon budget and cycle, it is important to understand the complex interrelationships involved in soil respiration rate (Rs). We attempted to reveal relationships between Rs and key environmental factors, such as soil temperature, using a laboratory incubation method. Soil samples were collected from mature deciduous (MD), mature coniferous (MC), immature deciduous (ID), and immature coniferous (IC) forests. Prior to measure, soils were pre-incubated for 3 days at $25^{\circ}C$ and 60% of maximum water holding capacity (WHC). Samples of gasses were collected with 0, 2, and 4 h interval after the beginning of the measurement at soil temperatures of 5, 15, 25, and $35^{\circ}C$ (at 60% WHC). Air samples were collected using a syringe attached to the cap of closed bottles that contained the soil samples. The $CO_2$ concentration of each gas sample was measured by gas chromatography. Rs was strongly correlated with soil temperature (r, 0.93 to 0.96; P < 0.001). For MD, MC, ID, and IC soils taken from 0-5 cm below the surface, exponential functions explained 90%, 82%, 92%, and 86% of the respective data plots. The temperature and Rs data for soil taken from 5-10 cm beneath the surface at MD, MC, ID, and IC sites also closely fit exponential functions, with 83%, 95%, 87%, and 89% of the data points, respectively, fitting an exponential curve. The soil organic content in mature forests was significantly higher than in soils from immature forests (P < 0.001 at 0-5 cm and P < 0.005 at 5-10 cm) and surface layer (P = 0.04 at 0-5 cm and P = 0.12). High soil organic matter content is clearly associated with high Rs, especially in the surface layer. We determined that the incubation method used in this study have the possibility for comprehending complex characteristic of Rs.

• 농약과학회지
• /
• 제7권3호
• /
• pp.182-187
• /
• 2003

제초제 mefenacet의 토양 중 분해 특성을 알아 보고자 2 종의 토양을 비살균 토양을 대조로 하여 몇가지 조건으로 전처리한 다음 120일 동안 항온배양하면서 그 잔류량을 분석한 결과 약제처리 후 70일 경과시 대조토양은 $55\sim63%$가 분해 소실되었으나 살균토양에서는 $32\sim33%$, 담수토양에서는 $33\sim35%$가 소설 되어 mefenacet의 분해에 토양 미생물의 활성이 크게 영향을 끼치는 것으로 나타났다. 또한 mefenacet의 토양 중 분해에 미치는 수분함량의 영향을 조사한 결과 90 일간 배양 시 그 반감기는 포장 용수량의 20%와 50%에 해당하는 7.8%, 19.5%의 수분이 첨가된 토양에서는 각각 83과 82일 이었으며 80%인 31.2%의 수분이 첨가된 토양의 반감기가 61일로 단축되어 토양 수분 함량이 높을수록 mefenacet의 토양 중 분해 소실이 빠르게 일어남을 알 수 있었다. 결과적으로 mefenacet의 토양 중 분해 소실에는 토양 성분 중 유기물 함량과 토양 수분 함량이 중요한 인자로 작용하며 토양 미생물이 토양 성분과 더불어 mefenacet의 분해에 중요한 역할을 하고 있음을 시사하고 있다.