1,017 research outputs found
EFFECT OF CUP AND BALL TYPES ON MECHANO-CHEMICAL SYNTHES IS OF Al2O3–TiC NANOCOMPOSITE POWDER
Al2O3–TiC nanocomposite powder was successfully synthesized by ball milling TiO2, Al and graphite powders. Effects of cup and ball type, milling time and annealing were investigated. XRD was used to characterize milled and annealed powders. The morphological and microstructural evolutions were studied by SEM and TEM. Results showed that the formation of this composite begins after 20 h and completes after 35 h of milling with stainless steel cup and balls. In contrast, there is no reaction during milling (up to 80 h) with ZrO2 cup and balls. Fe and ZrO2 were the major impurities introduced during milling with stainless steel and ZrO2 cups, respectively. The Fe impurity was removed by leaching in 3HCl·HNO3 solution for 4 days. Mean grain size less than 7 nm was achieved at the end of milling. In spite of grain growth, this composite maintained its nanocrystalline nature after annealing at 1000°C
Neutron Stars with Baryon Number Violation, Probing Dark Sectors
The neutron lifetime anomaly has been used to motivate the introduction of new physics with hidden-sector particles coupled to baryon number, and on which neutron stars provide powerful constraints. Although the neutron lifetime anomaly may eventually prove to be of mundane origin, we use it as motivation for a broader review of the ways that baryon number violation, be it real or apparent, and dark sectors can intertwine and how neutron star observables, both present and future, can constrain them
Effect of different dietary protein levels and water salinities on biochemical heamolymph parameters of white leg shrimp (Litopenaeus vannamei) juvenile
In this study, biochemical heamolymph parameters indices of the white leg shrimp (Litopenaeus vannamei) with three dietry protein levels (25, 35 and 45%) in the three levels of water salinity(0-3, 12-15 and 32-35 ppt) was studied. For experimental 350 shrimps with the average weight of 5.55±0.18 g and length of 8.81±0.15 cm were distributed randomly in 27 ten tones (length: 600 cm, width: 170 cm and height: 100 cm) concrete tanks. Experimental group were fed to satiation 4 times a day the experimental period. The results showed that at dietary protein levels of 35 and 45% and the water salinity of 32-35 ppt the amount of protein, urea, HDL and LDL increased (p≤ 0/05). Cholesterol and triglycerides levels in treatment with dietry protein level of 45% and the salinity of 32-35 ppt had increased. The glucose level of the plasma changed only by the modification of the protein level and had a revers relation with this variable (p≤ 0/05). However, different levels of protein and salinity had no effect on the amount of hemolymph uric acid. So besed biochemical heamolymph parameters on the results of this study, in dietry protein level 35% and salinity of 32-35 ppt and at least stress in the levels
The innate immunity changes of the female anadromous hilsa shad, Tenualosa ilisha , during spawning and post spawning season
Tenualosa ilisha (Hamilton) is a valuable migratory fish belonging to the family Clupeidae and it is distributed in a wide area from the Persian Gulf to coasts of Pakistan and China’s southern sea. The aim of the present study was to investigate the changes occurring in innate immunity parameters during upstream migration and comparing them to those during post spawning. Sixty mature female hilsa shad were obtained using gill net from Karoon River in Khorramshahr during the spawning period (July, August and September 2014) and Hendijan coasts along the Persian Gulf coasts during post spawning period (October, November and December 2014). Immediately, blood samples were collected from the peduncle vein and then parameters including WBC (White Blood Cell) count, Differential WBC Count, plasma lysozyme content and C3 and C4 complement activity were determined. Based on the results, the levels of WBC, lysozyme and C3 during the spawning period were lower than those recorded during post spawning period. However, C4 levels were higher during spawning (p<0.01). This fact revealed that some innate immunity parameters experience depression during upstream migration and spawning, while these parameters increase during the post spawning period, indicating the suppressive effects of spawning on fish immunity
Intestinal digestive enzyme activity under the influence of different dietary supplements methionine and lysine in the diet of Sparidentex hasta
This study was conducted to determine the effects of dietary methionine and lysine supplementation on digestive enzymes activity in juvenile Sobaity, Sparidentex hasta. For this purpose, 180 juvenile fish with an initial average weight of 31.38 ± 1.4 g were distributed randomly in eighteen (300 L) polyethylene tanks. 6 experimental diets were prepared with different levels of methionine and lysine including control diet (without dietary methionine and lysine), Diet 1: 100% methionine; Diet 2: 75% methionine and 25% lysine; Diet 3: 50% methionine and 50% lysine; Diet 4: 25% methionine and 75% lysine; Diet 5: 100% lysine. During the experimental period, fish were fed to satiation thrice daily (8:00, 13:00 and 18:00 hours) for 8 weeks. At the end of the experiment, digestive enzymes (trypsin, chymotrypsin, alkaline phosphatase, amylase, lipase and total protease were affected by different dietary levels of methionine and lysine supplementations (P<0/05). Also, the activity of trypsin and chymotrypsin had shown an increasing trend with an increased amount of diet lysine while enzyme activity of alkaline phosphatase was higher in treatments contains the maximum amount of methionine supplementation. According to results, the increasing of lysine in diet reduced enzyme activity of lipase. The results, showed no significant differences between experimental treatments in amylase and total protease (P<0/05). Based on the results of evaluation digestive enzymes, amino acids supplements of lysine and methionine were changed the activity of digestive enzymes in juvenile Sobaity, (S. hasta). Finally, Diet 2 with 75% methionine and 25% lysine was suggested for used by Sobaity, as to the balance of dietary methionine and lysine supplementation
A comparison of different parameter correlation models and the validation of an MEA-based absorber model
AbstractConsiderable effort on research in CO2 capture technologies has been directed towards steady state systems while less seems to have been done for the same systems in transient state. This work presents a dynamic model for CO2 absorption using aqueous mono-ethanolamine (MEA). Validation against experimental results both obtained at steady state and dynamic conditions is included. A parametric sensitivity study of the underlying model equations is carried out based alternative parameter correlations for the reaction rate constant. It is concluded that validated results for one specific pilot plant don’t necessarily apply to other plants of different sizes under other operational conditions. Furthermore, a parametric sensitivity study for the other parameters as well as for the rest of the CO2 capture process is also warranted
Effects of amino acid supplementation of lysine and methionine on body biochemical composition and amino acid profile of Sobaity sea bream (Sparidentex hasta) juveniles
In this study that lasted to 8 weeks, was conducted to determine the effects of dietary supplementation of lysine and methionine on body biochemical composition and amino acid profile of Sobaity sea bream, Sparidentex hasta. Therefore, 180 juvenile fish with an initial weight of 31.38 ±1.4 g were distributed randomly among eighteen tanks. Fish were fed to satiation three time per day (08:00, 13:00 and 18:00 hours) with formulated diets containing six different levels of dietary methionine and lysine; Diet 1: a control diet without dietary amino acid supplementation; Diet 2: 100% methionine supplementation; Diet 3: 75% methionine and 25% lysine supplementation; Diet 4: 50% methionine and 50% lysine supplementation; Diet 5: 25% methionine and 75% lysine supplementation and Diet 6: 100% lysine supplementation.The results of this study showed Carcass protein content was significantly affected by the amino acid supplements and the highest level of carcass protein observed in fish were fed by diet 3(P 0.05). In addition, essential amino acids (ΣEAA) and non-essential amino acids (ΣNEAA) and ratio ΣEAA / ΣNEAA, were affected by lysine and methionine amino acid supplementation as ΣEAA and ratio (ΣEAA) / (ΣNEAA) significantly increased with increasing levels of amino acid supplementation and the highest amount of this parameters observed in groups were fed by diet with high levels of methionine.The results showed that adding 75% dietary methionine supplementation and 25% lysine supplemtation to the diet containg 45/95% protein, have positive effects on biochemical composition and amino acid profile in rearing of Sobaity seabream juveniles
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