Suitability of Flyash-Lime-Phosphogypsum Composite in Road Pavements

The paper presents the suitability of flyash-limephosphogypsum composite for its use in road pavements. The content of lime and phosphogypsum was varied from 2 to 10% and 0.5 to 4% respectively in flyash. The specimen prepared was cured for 7, 28, 56 and 90 days with burlap method of curing. Compaction tests were conducted on different flyash-lime-phosphogypsum composite and these results were used for casting cylindrical specimens for unconfined compressive strength, split tensile strength, slake durability and for determination of bearing ratio. It has been concluded that flyash-lime-phosphogypsum composite satisfy the unconfined compressive strength, split tensile strength, slake durability criteria as well as giving higher bearing ratio values at 28 days of curing. Good agreement is observed between the experimental values and predicted values for tensile strength, bearing ratio, slake durability indices. The developed models will be useful for making preliminary estimate of these parameters by the field engineers for planning purposes. The empirical models presented are based on the experimental data within the range of parameter (curing period 7 to 90 days) and materials tested. Beyond this range of values the model may be checked with experimental results. The models reported in literature under estimate the properties like bearing ratio, tensile strength and slake durability indices determined from the unconfined compressive strength. The flyash-lime-phosphogypsum composite (flyash + 8% lime + 2% phosphogypsum) cured for 28 days can be used as a base/subbase course material in road pavements

Unconfined Compressive Strength of Bentonite - Lime-Phosphogypsum Mixture Reinforced with Sisal Fibers

This paper presents the effect of sisal fibers on the unconfined compressive strength of bentonite. The present study is aimed at determining the behavior of bentonite-lime-phosphogypsum reinforced with sisal fibers in a random manner. The sisal fiber content was varied from 0.5 to 2 %. The results indicated that the unconfined compressive strength of bentonite can be increased by the addition of lime, phosphogypsum and sisal fibers. The increase in unconfined compressive strength was highest with 8 % lime, 8 % phosphogypsum and 1 % sisal fibers. The reference mix reinforced with sisal fibers was able to bear higher strains at failure as compared to bentonite and bentonite- lime-phosphogypsum mixture. With the increase in sisal fiber content (0.5 to 2 %) in reference mix, there was an increase in the unconfined compressive strength. The bentonite - lime-phosphogypsum-sisal fiber mixture will boost the construction of temporary roads on such problematic soils. Further, its use will also provide environmental motivation for providing a means of consuming large quantities of phosphogypsum and natural fibers

Potential of Bentonite-lime-mix Modified with Phosphogypsum and Reinforced with Sisal Fibres

The paper presents the potential of bentonite-limephosphogypsum mix reinforced with sisal fibre in effectively reducing the pavement thickness in an extremely problematic sub-soil condition intended for road construction. In view of which, compaction, unconfined compressive strength and California bearing ratio tests were conducted. The content of lime, phosphogypsum and sisal fibre was varied from 0 to 10%, 0 to 10% and 0 to 2% respectively. The specimens were prepared at their respective optimum moisture content and maximum dry unit weight for conducting the unconfined compressive strength and bearing ratio tests and were cured for 3 to 28 days. The results of this study reveal that the unconfined compressive strength and bearing ratio of the bentonite-lime-phosphogypsum mix increased with the increase in curing period. Addition of sisal fibres to the bentonite-limephosphogypsum mix changes the behaviour of the composite from brittle to ductile in the post peak region. Scanning electron micrographs and energy-dispersive X-ray analysis confirms the improvement in unconfined compressive strength and bearing ratio. The improved behaviour of the composite indicates that the sisal fibres have the potential for use in road pavements

Engineering Properties of Bentonite-Lime-Phosphogypsum Composite Reinforced with Treated Sisal Fibers

The present work primarily investigates the unconfined compressive strength, the tensile load-diametral strain, the toughness characteristics and the shear strengths of bentonite-lime-phosphogypsum-treated sisal fibre composite. The unconfined compressive strengths and tensile strengths were obtained using the unconfined compressive test and indirect tensile test respectively. The results revealed that the unconfined compressive stress, the deviator stress and the tensile load at failure of bentonite-lime-phosphogypsum composite with untreated sisal fibres could be improved by the successive chemical treatment with sodium periodate, p-aminophenol and sodium hydroxide. The brittleness index and deformability index indicated a change from the brittle to ductile behavior of the bentonite-lime-phosphogypsum-untreated sisal fiber composite, with the chemical treatment

Prospective observational study of vancomycin injection in SLED patient of ethnic Indians

As the Vancomycin is itself a nephrotoxic antibiotics, so it is sometime recommended to the Slow-low Efficiency Dialysis (SLED) patients against highly resisted infection. In this case, the dose monitoring is strictly maintained after Intravenous injection. The collected blood was analyzed for its concentration in HPLC for 11 patients and the half life was evaluated to study Therapeutic drug monitoring. The T1/2 of evaluated vancomycin is 39.12+ 6.81 hrs. The mean of the systemic clearance is 16.91+6.99 and mean Vd is 0.57+ 0.147. Comparatively the reported study of Mean + SD of half-life, volume of distribution, and systemic clearance were 43.1 + 21.6 hours, 0.84 L/kg + 0.17 L/kg, and 24.3 mL/min + 8.39 mL/min respectively. Thus the t-test of the means was 0.5828, degree of freedom (df) was 20, standard error of difference was 6.829 and so, the two-tailed P value is 0.5665 i.e. P > 0.5. In ethnic Indian SLED patients, T1/2 of mean + SD of 39.12 + 6.81 hrs was compared to the Caucasian patients i.e, 43.1 + 21.6 hrs. And the t-test and P-value is 0.5828 & 0.5665 respectively. Thus it was concluded that the half-life of ethnic Indian patients is less in compare to Caucasians but this difference is not so significant. The half-life of ethnic 8 patients is less than 40 out of 11 patients.Keywords: Vancomycin assay; Slow-low efficiency dialysis; Pharmacokinetic analysis; Ethnic indian

Engineering Properties of Bentonite Modified with Lime and Gypsum

This paper presents the engineering properties such as compaction, unconfined compressive strength, consistency limits, free swell index, California bearing ratio and consolidation of bentonite stabilized with lime and modified with gypsum. The content of lime and gypsum was varied from 0 to 10% and from 0.5 to 8%, respectively, to check the improvement in the engineering properties. The results of this study revealed that the dry unit weight and optimum moisture content of bentonite + 8% lime increased with the addition of 4% gypsum. The unconfined compressive strength of bentonite did not change with the increase in curing period. The unconfined compressive strength of bentonite + 8% lime increased with the addition of 4% gypsum. Beyond 4%, the unconfined compressive strength decreased. The unconfined compressive strength of bentonite-lime-gypsum mix increased with the increase in curing period. The liquid limit, plastic limit and free swell index of bentonite + 8% lime decreased; whereas the plasticity index increased with the addition of 4% gypsum. The California bearing ratio and modulus of subgrade reaction increased for bentonite stabilized with 8% lime and modified with 4% gypsum leading to reduction in earth work and required thickness of subgrade bentonite. The coefficient of consolidation of bentonite increased with the addition of 8% lime and did not change with the addition of 4% gypsum. The swell potential of bentonite + 8% lime increased with the addition of 4% gypsum. The improved behaviour of the bentonite-lime-gypsum mixture will boost the construction of road pavements on such problematic soils

Effect of Addition of Treated Coir Fibres on the Compression Behaviour of Clay

This paper presents the effect of treated coir fibres (15 mm in length) on the unconfined compressive strength of clay. Dry, sodium hydroxide and carbon tetrachloride–treated coir fibres were used in the study. The coir fibre content was varied from 0.4% to 1.6%. The results indicated that the unconfined compressive strength of clay and clay with dry coir fibres can be increased by treatment with carbon tetrachloride and sodium hydroxide. The increase in unconfined compressive strength was highest with carbon tetrachloride treatment. The clay reinforced with treated fibres was able to bear higher strains at failure as compared to clay and clay with dry fibres. With the increase in coir fibre content (0.4%-1.6%) in clay, there was an increase in the unconfined compressive strength. The clay with treated coir fibres can be used for making bricks for mud houses in rural India

Detection of Ascosphaera apis, causing chalkbrood disease in the colonies of European honey bee, Apis mellifera in West Bengal, India

The decline of honey bee (Apis mellifera L.) populations is of great concern around the world. Among the several key drivers, dissemination of pests and pathogens is potential one. Chalkbrood is very common fungal disease of honey bee, caused due to Ascosphaera apis. In the present study, survey was conducted regarding the prevalence of diseases in A. mellifera beekeeping in Gangetic plains of West Bengal, India. Results confirmed the occurrence of chalkbrood disease in different apiaries, where dead and mummified bee larvae with cotton like chalky white or greyish-black covering were found as physical symptoms of the disease. From three surveyed apiaries, a total of 16 hives out of 113 hives were found to be infected with the diseases; and 46 frames out of 132 frames from the infected 16 hives were found to be affected by the pathogen. Microscopic examination reflected that nearly 87% of the samples collected from the infected frame were found to be positive for the spore of Ascosphaera. The fungus associated with the disease was isolated on Potato Dextrose Agar medium, pure cultured and its genomic DNA was isolated to perform PCR and based on 18s rDNA sequencing by using specific primer pair of ITS-1 and ITS-4, the fungus was identified as Ascosphaera apis. Keywords: 18s rDNA, Bees, Necrotrophs, Phylogen

Soft Computing Based Prediction of Unconfined Compressive Strength of Fly Ash Stabilised Organic Clay

The current study uses machine learning techniques such as Random Forest Regression (RFR), Artificial Neural Networks (ANN), Support Vector Machines Ploy kernel (SVMP), Support Vector Machines Radial Basis Function Kernel (SVMRBK), and M5P model tree (M5P) to estimate unconfined compressive strength of organic clay stabilized with fly ash. The unconfined compressive strength of stabilized clay was computed by considering the different input variables namely i) the ratio of Cao to Sio2, ii) organic content (OC), iii) fly ash (FAper) content, iv) the unconfined compressive strength of organic clay without fly ash (UCS0) and v) the pH of soil-fly ash (pHmix). By comparing the performance measure parameters, each model performance is evaluated. The result of present study can conclude the random forest regression (RFR) model predicts the unconfined compressive strength of the organic clay stabilized with fly ash with least error followed by Support Vector Machines Radial Basis Function Kernel (SVMRBK), Support Vector Machines Ploy kernel (SVMP), Artificial Neural Networks (ANN) and M5P model tree (M5P). When compared to the semi-empirical model available in the literature, all of the model predictions given in this study perform well. Finally, the RFR and SVMRBK sensitivity analyses revealed that the CaO/SiO2 ratio was the most relevant parameter in the prediction of unconfined compressive strength