Comparison of plain and finned tubes during pool boiling of CaSO4 solutions

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.One of the most severe types of fouling occurs during pool boiling heat transfer. This has led some processes such as thermal desalination units, in particular, to be operated below saturation temperature to avoid rapid and severe formation of crystallized deposits e.g. CaSO4 on heat transfer surfaces. This has been despite superiority of pool boiling to other modes of heat transfer. This study investigates experimentally the formation of deposit on the finned tubes during pool boiling of CaSO4 solutions. The structured tubes are low finned tube type with a fin density of 19 fins per inch, 1.35 mm fin pitch and Cu-Ni as substrate. Fouling runs are carried out for different heat fluxes ranging from 100 to 300 kW/m2 and different salt concentrations at atmospheric pressure. For the sake of comparison, similar runs are also conducted for plain stainless steel tubes. Experimental results show for the finned tubes, substantial reduction of fouling compared to those of the plain tube. If any deposit forms on the surface then it is only a very thin and fragile layer of crystals which differs significantly to plain tubes which is characterized with a thick layer of deposit. In addition, the finned tubes perform much better at lower heat fluxes. Finally, the cleanability of finned tubes is also examined which show good performance.dc201

Ultrasonographic Diagnosis and Clinical Evaluation of the Foreign Body Complications in the Compound Stomach of Cattle and Buffaloes

This study was aimed to detect and record the clinical and ultrasonographic findings of the different complications resulted from the foreign bodies lodged in the compound stomach of cattle and buffaloes. A total of 105 animals (37 cattle and 68 buffaloes) were subjected to study. Based on the clinical and ultrasonographic examination, animals were classified into; acute local reticuloperitonitis (ALRP) (15 cattle and 28 buffaloes), chronic local reticuloperitonitis (CLRP) (6 cattle and 14 buffaloes), acute diffuse reticuloperitonitis (ADRP) (5 cattle and 3buffaloes), reticular abscesses (RA) (4 cattle and 7 buffaloes), traumatic pericarditis (TP) (6 cattle and16 buffaloes) and liver abscess (one cattle). Results revealed that ALRP represented the highest percentage of 40.5% in cattle and 41.2 % in buffalos between the different complications of TRP. TP represented the second complications of higher incidence (16.2% in cows and 23.5% in buffalos). Liver abscess represented the lowest percentage (2.8%) and was recorded in cows only. The pregnant animals were affected more than the non pregnant. Clinical findings represented in systemic reaction and pain tests were commonly encountered in TRP and its complications. Some of the affected animals were negatively respond to metal detector test. Results of the present study indicated that the ultrasonographic examination provide a specific echogenic pattern for the different complications of TRP. It was concluded that, clinical examination only is not efficient to give accurate diagnosis of foreign body lodged in the reticulum and rumen and their complications. Ultrasonography is a safe, non invasive diagnostic confirmatory method that could be used for early detection of such conditions

Honey bee immunity and physiology are enhanced by consuming high-fat diets

This study aimed to evaluate the nutritional behavior and some immunological criteria (encapsulation index and phenoloxidase – PO activity, the key enzyme for melanization) as well as to study the effect of protein to fat (P : F) diets on hypopharyngeal gland (HPG) protein content. Bees were restricted to consuming specific P : F diets varying in fat ratio under laboratory conditions. These diets included 25 : 1, 10 : 1, 5 : 1 (low-fat diet, LFD); 1 : 1 (equal-fat diet); 1 : 5, 1 : 10 (high-fat diet, HFD), and 1 : 0 (zero-fat diet) as a control. Bees preferred low-fat diets over high-fat diets, where it was 11.27 ± 0.68 μl · day–1 bee in 10 : 1 P : F, while it was 4.99 ± 0.67 μl · day–1 bee in 1 : 10 P : F. However, sucrose consumption was higher in high-fat diets where it was 25.83 ± 1.69 μl · day –1 bee in 10 : 1 P: F, while it was 30.66 ± 0.9 μl · day–1 bee in 1 : 10 P : F. The encapsulation index and phenoloxidase activity of bees were positively linked with the fat level they consumed during all 10 days. The maximum percentage of encapsulation index was 74.6 ± 7.2% in bees fed a high-fat diet, whereas the minimum percentage was 16.5 ± 3.6% in bees which consumed a lowfat diet. Similarly, phenoloxidase activity increased in the haemolymph with increasing fat consumed by bees (0.001 ± 0.0001 and 0.005 ± 0.0003 mM · min –1 · mg –1 at 25 : 1 and 1 : 10 P : F, respectively). The protein content of hypopharyngeal glands in bees which consumed HFD was double that of LFD. Overall results suggest a connection between a fat diet and bee health, indicating that colony losses in some cases can be reduced by providing a certain level of fat supplemental feeding along with sucrose and protein nutrition

Immobilization of halophilic Aspergillus awamori EM66 exochitinase on grafted k-carrageenan-alginate beads

A novel extreme halophilic exochitinase enzyme was produced by honey isolate Aspergillus awamori EM66. The enzyme was immobilized successfully on k-carrageenan-alginate gel carrier (CA) with 93 % immobilization yield. The immobilization process significantly improved the enzyme specific activity 2.6-fold compared to the free form. The significant factors influencing the immobilization process such as enzyme protein concentration and loading time were studied. Distinguishable characteristics of optimum pH and temperature, stability at different temperatures and NaCl tolerance for free and immobilized enzyme were studied. The immobilization process improved optimum temperature from 35 to 45 °C. The immobilized enzyme retained 76.70 % of its activity after 2 h at 75 °C compared to complete loss of activity for the free enzyme. The reusability test proved the durability of the CA gel beads for 28 cycles without losing its activity

Effect of Narrow-Band Ultraviolet B Phototherapy and Methotrexate on MicroRNA (146a) Levels in Blood of Psoriatic Patients

Background. Recently, some miRNAs have been proven to show aberrant expression in psoriasis and play a role in the pathogenesis of the disease. Objective. To find out whether NB-UVB or methotrexate treatment affects whole blood levels of human miRNA (146a) in patients with psoriasis and demonstrate its correlation with disease severity. Methods. Blood samples were obtained from healthy control and from psoriatic patients before and 12 weeks after treatment with NB-UVB, methotrexate. Quantification of human miRNA (146a) by Real Time PCR (RT-PCR). Results. Blood human miRNA (146a) levels were higher in patients with psoriasis than those in healthy controls (P=0.001); it had no significant positive relation with PASI scores in patients (r=0.2, P=0.107). Real Time PCR showed that, after 12 weeks of treatment with NB-UVB phototherapy or treatment with methotrexate, there was significantly decreased level of miR146a (P=0.001; P=0.002, resp.). Conclusion. The expression of miRNA146a is increased in whole blood samples from psoriasis patients, so we can evaluate its possibility to work as a future therapeutic objective in the treatment of psoriasis. With these markers, it is able to screen therapeutics effect or changes to a further aggressive treatment for psoriasis

New formulation of production media for submerged cultivation of aspergillus niger for production of pectinase

Pectinase is a generic term that used from derivation of the pectin. Pectin is a complex class of carbohydrates polymer which composed of members galacturonic acid that linked through the a-1-4 glycosidic linkage and it is widely found in the primary cell walls or at the middle lamella of higher plants . Furthermore, Among different biofactories of pectinases, the filamentous fungi provide a potentially high yielding and relatively cheap option and the genus of Aspergillus has been used with a success as a production host . Therefore, the objective of this research is to develop industrial production media and a cultivation strategy for the production and secretion of pectinases in a semi-industrial scale by A. niger. In this study, the submerged cultivation was chose as a cultivation strategy for the production and secretion of pectinase in a semi-industrial scale by A. niger

Production and Immobilization of Halophilic Invertase Produced from Honey Isolate Aspergillus niger EM77 (KF774181)

Honey isolate Aspergillus niger EM77 was a good halophilic invertase producer in the presence of wheat bran as a complete medium (114.55 U/g), using solid state fermentation technique. Different parameters influence the enzyme productivity such as different pH values, temperature, incubation period, nitrogen and carbon sources were investigated. The optimum pH, temperature and incubation period for enzyme production were 5.5, 30oC and 72 hrs, respectively. Sucrose at 2 % was more suitable carbon source for invertase production (144.39 U/g) and (NH4)2SO4 at 0.15 % was the ideal nitrogen source. Among different metals ions MnSO4 enhanced the enzyme productivity than other tested ions to 194.71 U/g. The partially purified enzyme was successfully entrapped in polyvinyl alcohol sponge shielded with agar starch layer (PVAsp Gs) and achieved 71% immobilization yield. The optimum conditions for immobilization were: pH 5.2, an incubation time of 15 min and a protein concentration of 250 mg/ml. Immobilized enzyme was reused 12 times with 29% activity loss. The free enzyme lost its activity completely at 70˚C after 45 minute and the immobilized form retained 80% of its activity at the same condition.The free and immobilized form reported extreme halophilic property since the highest enzyme activity was obtained between 3.5- 5 M

Bioprocess optimization for pectinase production using Aspergillus niger in a submerged cultivation system

Background: Pectinase enzymes present a high priced category of microbial enzymes with many potential applications in various food and oil industries and an estimated market share of $ 41.4 billion by 2020. Results: The production medium was first optimized using a statistical optimization approach to increase pectinase production. A maximal enzyme concentration of 76.35 U/mL (a 2.8-fold increase compared with the initial medium) was produced in a medium composed of (g/L): pectin, 32.22; (NH4)2SO4, 4.33; K2HPO4, 1.36; MgSO4.5H2O, 0.05; KCl, 0.05; and FeSO4.5H2O, 0.10. The cultivations were then carried out in a 16-L stirred tank bioreactor in both batch and fed-batch modes to improve enzyme production, which is an important step for bioprocess industrialization. Controlling the pH at 5.5 during cultivation yielded a pectinase production of 109.63 U/mL, which was about 10% higher than the uncontrolled pH culture. Furthermore, fed-batch cultivation using sucrose as a feeding substrate with a rate of 2 g/L/h increased the enzyme production up to 450 U/mL after 126 h. Conclusions: Statistical medium optimization improved volumetric pectinase productivity by about 2.8 folds. Scaling-up the production process in 16-L semi-industrial stirred tank bioreactor under controlled pH further enhanced pectinase production by about 4-folds. Finally, bioreactor fed-batch cultivation using constant carbon source feeding increased maximal volumetric enzyme production by about 16.5-folds from the initial starting conditions