Viscosity , Relaxation and Stability of Natural Rubber
Mooney viscosity and Mooney relaxation of unaged and oven aged SMR L natural rubber samples were studied. The viscosity was characterized by ML (1+4) 100°C and the rate of stress relaxation by the exponent a in a power law M = k (t) a . With the increasing time of oven aging at 140°C the decrease of both viscosity and stress relaxation rate exponent were observed. Aging of raw natural rubber can therefore be studied by Mooney viscosity and Mooney relaxation tests and obtained results are sensitive enough to be used for characterization of raw natural rubber stability.
CHARACTERISTICS OF RUBBER SHEET WITH RAW MATERIAL OF COMPOSITE MODIFICATIONS - LATEX
Natural starch can be made into modified starch with the desired properties or as needed. Composite of starch and natural rubber for the made of rubber sheets as an alternative to reduce the use of natural rubber in large quantities. The research aimed to study the characteristics of sheets rubber with composite modified starch - latex. The experimental research used non Factorial Completely Randomized Design and each treatments was replicated three times. Single factor of starch and latex modification ratio (Treatment A Starch modification: latex = 1: 1 (500 ml: 500 ml, Treatment B Starch modification:latex = 1:2 (500 ml: 1000 ml and Treatment C Starch modification:latex = 2:1 (1000 ml: 500 ml)). The parameters were plasticity (Po), plasticity resistance index (PRI), mooney viscosity and dirt content. Results showed that the comparison treatment of starch and latex modifications have a influence on the characteristics of sheet rubber meet the quality requirements of Standard Indonesian Rubber (SIR) 20 SNI 06-1903-2000 and standard quality commercial sheets rubber with charactheristics plasticity (Po), plasticity resistance index (PRI), mooney viscosity and dirt content.
Diagnostic and therapeutic studies on chronic diarrhea in dairy animals
The study was conducted to determine the etiology of chronic diarrhea in dairy animals. Seven causes of chronic diarrhea were established in dairy cattle and buffaloes. Balantidiasis in 37.6 per cent, dietary diarrhea in 9.9 per cent, chronic salmonellosis in 6.9 per cent cases of chronic diarrhea, secondary copper deficiency and amphistomiasis in 6.9 per cent, clinical Johne‘s disease in 3.9 per cent and chronic peritonitis in 2.97 per cent of dairy animals, manifest chronic diarrhea. The precise diagnosis could not be established in 24.50 per cent of animals. Lymphosarcoma was confirmed in one of the dairy cattle. Body condition score was associated to the etiology of chronic diarrhea. B. coli infected cattle and buffalo revealed cysts in 32.3 per cent cases while 5 per cent positive cases revealed both cysts and trophozoites. Mean cyst count was 2.73±0.91 hpf in diarrheic animals compared to 0.11±0.447 hpf in healthy animals. Clinical Johne‘s disease was confirmed in four animals. Hematological changes revealed anemia and neutrophilia with morphological changes suggestive of regenerative to degenerative left shift. High plasma phosphorus, hypoproteinaemia and hypoalbuminaemia was seen in clinical Johne‘s disease. Salmonella isolates showed higher in-vitro sensitivity to enrofloxacin (87%), ciprofloxacin (87%), gentamicin (75%), and tetracycline (66.7 %) and were resistant to ampicillin and amoxicillin. Mean cyst count reduction from 2.41±1.16 to 0.11±.33 was observed in oral metronidazole treated group where as reduction of mean cyst count from 2.73±0.918 to 0.18±0.44 in intravenous metronidazole treated group. Recovery rate with oral and intravenous metronidazole was 42.1 and 63.1 per cent respectively. Recovery results in significant decrease in eiosionphil count and increase in total plasma protein in both oral and intravenous treatment groups. Complete recovery response approaches 60 per cent in balantidiasis affected adult dairy animals. Balantidiasis was the major cause of chronic diarrhea and intravenous administration of metronidazole was more effective than oral metronidazole.