Studies on the utilization of red mud for environmental application

Red mud is a waste by product generated from alumina processing industries which creates a number of environmental problems. Reports of the utilization of the red mud for the treatment of natural, industrial and domestic waste water are available in literature. Clean water and a clean environment are the today’s requirements. The use of one waste for the removal of another waste is a challenging job. The present dissertation is an embodiment of the investigations for developing simple inexpensive adsorbents by the modification of red mud for waste water purification. In laboratory scale, neutralization of highly alkaline red mud is carried out by acid and CO2 gas treatment and modified by calcination. In another method, red mud adsorbent is prepared by surface modification with the impregnation of an anionic surfactant SDS. After modification, the red mud is called as Activated red mud (ARM) which is used as an adsorbent. The adsorbents (ARM) are used for the removal of Pb(II), Cd(II) ions and organic safranin-O dye separately from aqueous solutions in batch mode. The adsorbents, before and after treatment are characterized by XRD, SEM, EDX, TGA-DSC, FTIR, UV-Visible, BET surface area .The AAS analytical techniques is used to measure the residual metal ion concentration in treated water. The activated red mud used for the removal of hazardous Pb(II) possess the rounded shape aggregate particles with surface area 67.10 m2/g and particle size in the range of 0.1–150 µm . The maximum adsorption capacity as calculated from Langmuir isotherm model is found to be 6.0273 mg/g at pH 4. The pseudo-second-order kinetics describes the adsorption process. The adsorption process is described by ion exchange mechanism. The maximum adsorption capacities of Cd(II) on activated red mud (ARM) are found to be 12.046 and 12.548 mg/g at temperature 293 and 303 K, respectively. The endothermic, spontaneous and feasible nature of adsorption is known from the thermodynamic parameters. The external mass transfer coefficient (kf ) is found to be 0.084 ×10 -3, 0.012 ×10 -3 at temperature 293 K and 9.9 ×10 -3, 11.5 ×10 -3 at 303 K which are evaluated by the McKay et al: and Weber–Mathews equation respectively. The desorption efficiency of Cd(II) is found to be 91.29% with 0.2 mol/L HCl. The BET surface area of the SDS/RM is found to be 67.10 m2/g. The maximum adsorption capacity of modified red mud (SDS/RM) is found to be 8.94 mg/g at temperature 308 K and pH 4 obtained from Langmuir isotherm model. The external mass transfer coefficient (kf ) value as obtained from McKay et al: equation is found to be 3.49 ×10¬¬-4 , 4.61 ×10 -4 at temperature 308 K and 2.13 ×10 -4, 3.11 ×10 -4 at 328 K obtained from Weber–Mathews equation .These values indicate the faster adsorption of safranin-O on the surface of ARM at lower temperature. The response surface methodology (RSM) is applied to examine the efficiency of the removal of safranin-O dye from aqueous solution by the activated red mud neutralized by CO2 gas. A 24 full factorial central composite design (CCD) method is used to evaluate the effects of adsorption parameters. The operating parameters for maximum uptake capacity of 9.768 mg/g is; adsorbent dose (0.62 g), temperature (29.06 ℃), pH (8.3) and initial safranin-O concentration (37.3 mg/L). At this optimum condition, the adsorption of safranin-O from aqueous solution is found to be 94.5%

Performance Efficiency Measurement of Airports: A Comparative Analysis of Airports Authority of India and Public Private Partnership

This article describes how to improve the overall efficiency and effectiveness of the aviation sector and also to source extra funding, the Government of India has paved the way for private investors through to a Public Private Partnership (PPP) model since the 1980s. This liberalization step in the Indian aviation market has minimized the institutional barriers which have hindered the freedom and flexibility of air transport operations among private investors. Now, competition within the aviation sector has become fiercer; the Airports Authority of India (AAI) and Public Private Partnership (PPP) in Indian airports are not only providing varied services, but also attracting consumers with new infrastructure and full modern facilities. The importance of this article is because after privatization, no studies have been conducted to examine the efficiency of Indian airports by using Data Envelopment Analysis (DEA). An output-oriented DEA model is employed to determine the efficiency score of airports by taking a sample of 15 airports, including airports run by PPP, for comparison. Output-oriented DEA calculates the efficiency by maximizing the outputs for a given level of inputs. Therefore, this article contributes to the existing literature on Indian airports. Based on available data, three variables - length of runways, terminal size and number of check-in counters, are used as inputs and two variables - passenger movement and aircraft movement, are used as outputs.N

Motion of an air bubble under the action of thermocapillary and buoyancy forces

A novel way to handle surface tension gradient driven flows is developed in the volume-of-fluid (VoF) framework. Using an open source Navier-Stokes solver, {\it Basilisk}, and the present formulation, we investigate thermocapillary migration of drops/bubbles in a surrounding medium. Several validation exercises have been performed, which demonstrate that the present solver is a robust one to investigate interfacial flows with variable surface tension. It is well known that it is a challenging task to numerically model the tangential and normal surface forces arising due to interfacial tension. We have shown that the present method does not require the artificial smearing of surface tension about the interface, and thus predicts the theoretical value of the terminal velocity of bubble/drop migrating due to an imposed temperature gradient very well. It is also demonstrated that the present solver provides accurate results for problems exhibiting the gravity and thermocapillary forces simultaneously, and useful for systems with high viscosity and density ratios.Comment: 30 pages, 16 figures, submitted to Computers and Fluid

Clinical and Bacteriological profiles of patients with Acute Cholangitis.

INTRODUCTION : Acute cholangitis, is an infection of the biliary system with a wide spectrum of clinical presentations. In its most severe form, it is life threatening and associated with significant morbidity and mortality. Stone in the CBD is the most common cause of acute cholangitis. Other causes of cholangitis are neoplasm, benign strictures, parasitic infections, post operative conditions like sump syndrome and post choledochoduodenostomy and congenital anomalies of the bile ducts. In patients with bacterial cholangitis, bacteremia is seen in 1/3rd of blood cultures. Over two-thirds of the bile cultures show mixed infection of two or more organisms. Empiric broad- spectrum antibiotics and prompt biliary decompression, the mainstay of therapy significantly improves outcomes. There is no study from India which compares etiology, microbiological profile, interventions and outcomes in patients with acute cholangitis from different regions of the country. There is also no Indian data evaluating anaerobic cultures (blood / bile) in patients with acute cholangitis. Aims and Objectives : 1) To study the etiological profile, clinical features, interventions and outcomes in patients with acute cholangitis from different regions of the country. 2) To study the bacteriological profile (aerobic and anaerobic) and antibiotic sensitivity in a subset of prospectively enrolled patients with acute cholangitis. CONCLUSIONS : The most common cause of biliary obstruction in patients with acute cholangitis is stone disease (Choledocholithiasis). Malignant disease is responsible for obstruction in 1/3 of patients. Ultrasound examination of abdomen is an effective, inexpensive and non-invasive test for diagnosis of biliary obstruction. It should be the initial imaging test performed in patients with acute cholangitis. Bacteremia with single organisms (Gram negative) is seen in 1/3rd of patients with acute cholangitis, Gram positive organisms are rare in blood cultures. More than 90% of bile cultures show positive growth with multiple organisms in 2/3rd of the cultures. Most common organisms are E.coli and Enterococcus, followed by Klebsiella and Pseudomonas. The bacteriological profile has not changed over time. It is the same in our patients over the past 5 years. Anaerobic bacteria were not grown in bile or blood in the present study

Comparison of clinical and CSF profiles in 62 Adults with tuberculous and pyogenic meningitis

Background: Many a times differentiating tuberculous meningitis from pyogenic meningitis becomes very difficult. The diagnosis depends upon clinical manifestation and cytochemical analysis of cerebrospinal fluid (CSF). Many researchers found that the CSF glucose: protein ratio less than 0.5 and Adenosine deaminase levels (ADA) in cerebrospinal fluid are useful to differentiate tubercular disease from non-tubercular meningitis.Methods: Sixty-two patients admitted to our tertiary hospital with symptoms and signs of meningitis were selected and divided into two groups: tubercular (n=39) and pyogenic (n= 23), depending upon the accepted criteria. Clinical features and CSF parameters noted in each patient. Cut off value of ADA kept at or above 10 IU/L for tubercular meningitis.Results: The mean age of patients with tubercular meningitis was 39.07±16.67 years and that of pyogenic meningitis 34.35±16.73 years. Clinically fever was present in 60 (96.77%), headache in 49 (79.03%), and vomiting in 44 (70.96%) patients. Meningeal signs – neck rigidity in 46 (74.2%), Kernig’s sign in 37 (59.68%) and Brudzinski’s sign in 18 (29.03%) patients. On CSF cytological and biochemical analysis the mean total white blood cell count was 256.74±184.03 /cmm, mean protein 182.22±113.12 mg/dl and mean sugar 52.85±19.3mg/dl in TBM whereas in pyogenic meningitis 106.17±185.18 / cmm, 88.78±114.35 mg/ dl, and 63.47±19.48 mg/dl respectively. Out of 39 tuberculous patients, 33 patients were found to be having CSF ADA at or above the cutoff value of 10 IU/L while only one among pyogenic meningitis. On comparison between two groups, the CSF ADA level found to be statistically highly significant (P < 0.001) with overall accuracy of the test was 85.5 %.Conclusions: We found that the duration of illness, estimation of cerebrospinal fluid ADA with a cut off value of 10 IU/L and CSF glucose: protein ratio of 0.5 may useful in differentiating tuberculous from pyogenic meningitis. posterior cranial fossa surgeries. This work will also be useful to anthropologists, forensic science experts for determination of sex of the skull along with other parameters

Occurrences of thrombocytopenia with valproic acid used for psychiatric indication

Background: The main aim of this study is to find out the effect of valproic acid on platelet count and to know the possible risk factors for thrombocytopenia in patients taking valproate (VPA).Methods: On 72 patients having psychiatric indication, a longitudinal observational study was designed and conducted from February 2012 to July 2013 at Department of Psychiatry (out-patient department) of Pt. Jawahar Lal Nehru Memorial Medical College and Dr. Bhim Rao Ambedkar Memorial Hospital, Jail Road, Raipur, Chhattisgarh. Platelet count was monitored and determined using an automatic coulter analyzer. The patients were followed up to 6 months. Statistical tool standard deviation ± was used for statistical analysis. p<0.05 is considered as statistically significant.Results: Total percentage of thrombocytopenia was found to be 12.5%; among that males constitute 9.8% and females 19.04%. The maximum number of cases falls in the age group between 51 and 60 years (55.5%). The major diagnostic group was reported to be consisted of mania (40.4%), followed by resistant cases of schizophrenia (25%) and then bipolar affective disorder (23.6%). The study indicated that maximum patients suffered from mild thrombocytopenia (11.1%) and (1.4%) patients have moderate thrombocytopenia. The mean time from exposure to VPA therapy to the first episode of thrombocytopenia was reported 92 days.Conclusions: Our findings underlined the importance of monitoring platelet counts in patients treated with VPA. This monitoring should be continued indefinitely on monthly basis. The studies indicate that the demands of more vigilant monitoring of patients should occur in age of 50-60 years, and result of entire studies indicates that females were found to be subjected to incidences of thrombocytopenia especially

THD Analysis of a Seven, Nine, and Eleven Level Cascaded H-Bridge Multilevel Inverter for Different Loads

A multilevel inverter is implemented for generating the required staircase AC voltage of output from various steps of voltages of DC sources. The multilevel inverter gives a better harmonic spectrum and a compatible quality of output. This article delves into an analytical analysis of the total harmonic distortion (THD) of different multilevel inverters which employ a multicarrier PWM technique. This technique is implemented for operating the switches at their respective angle of conduction. This paper deals with various cascaded H-Bridge multilevel inverters (CMI) with various loads that are modelled by implementing the MATLAB/Simulink platform. The output gives a better result of the proposed model in terms that it is helpful towards reducing the THD and the losses of switching

Titania coated silica nanocomposite prepared via encapsulation method for the degradation of Safranin-O dye from aqueous solution: Optimization using statistical design

AbstractTitania coated silica nanoparticles, which were synthesized via nanoparticle encapsulation route, are employed to degrade safranin-O dye from aqueous solution under UV light irradiation and were characterized by FT-IR, XRD, FESEM, N2 adsorption-desorption method and Zeta potential measurement. The results showed that the nanoparticles have a core-shell structure composed of about 100nm of diameter of silica with several TiO2 fine particles in shell. After the degradation, this process is optimized through the response surface methodology (RSM). In this response study, photodegradation efficiency was evaluated by three main independent parameters such as catalyst dose, initial dye concentration and reaction time. Parameter sensitivity studies of the degradation efficiency of titania coated silica nanoparticles have shown 93.29% degraded under the optimal conditions of catalyst dose of 89.80mg/g, initial dye concentration of 17.61mg/L and reaction time of 12min. We cross-checked the predicted values of degradation efficiency with the experimental values and were found to be in good agreement (R2=0.9983 and adj-R2=0.9967)