An analytical characterization study on biofuel obtained from pyrolysis of Madhuca longifolia residues.

The current study focuses on examining the characteristics of biofuel obtained from the pyrolysis of Madhuca longifolia residues, since the selected forest residue was primarily motivated by its greater volatile matter content. The study used several analytical techniques to describe pyrolysis oil, char, and gas obtained from slow pyrolysis process conducted between 350 and 600 °C in a fixed-bed reactor. Initially, the effect of process temperature on product distribution was assessed to motivate maximum pyrolysis oil yield and found to be 44.2 wt% at pyrolysis temperature of 475 °C, while the yields of char and gas were 22.1 wt% and 33.7 wt%, respectively. In order to determine the suitability of the feedstock, the Madhuca longifolia residues were analyzed by TGA and FT-IR, which revealed that the feedstock could be a feasible option as an energy source. The characterization of pyrolysis oil, char, and gas has been done through various analytical methods like FT-IR, GC-MS, and gas chromatography. The physicochemical characteristics of the pyrolysis oil sample were examined, and the results showed that the oil is a viscous liquid with a lower heating value than conventional diesel. The FT-IR and GC-MS analysis of pyrolysis oil revealed the presence of increased levels of oxygenated chemicals, acids, and phenol derivatives. The findings of the FT-IR analysis of char indicated the existence of aromatic and aliphatic hydrocarbons. The increased carbon content in the char indicated the possibility of using solid fuel. Gas chromatography was used to examine the chemical structure of the pyrolysis gas, and the results showed the existence of combustible elements.

Experimental investigation on utilization of Sesbania grandiflora residues through thermochemical conversion process for the production of value added chemicals and biofuels.

All the countries in the world are now searching for renewable, environmentally friendly alternative fuels due to the shortage and environmental problems related with the usage of conventional fuels. The cultivation of cereal and noncereal crops through agricultural activities produces waste biomasses, which are being evaluated as renewable and viable fossil fuel substitutes. The thermochemical properties and thermal degradation behavior of Sesbania grandiflora residues were investigated for this work. A fluidized bed reactor was used for fast pyrolysis in order to produce pyrolysis oil, char and gas. Investigations were done to analyze the effect of operating parameters such as temperature (350-550 °C), particle size (0.5-2.0 mm), sweeping gas flow rate (1.5-2.25 m3/h). The maximum of pyrolysis oil (44.7 wt%), was obtained at 425 °C for 1.5 mm particle size at the sweep gas flow rate of 2.0 m3/h. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry methods were used to examine the composition of the pyrolysis oil. The pyrolysis oil is rich with aliphatic, aromatic, phenolic, and some acidic chemicals. The physical characteristics of pyrolysis oil showed higher heating value of 19.76 MJ/kg. The char and gaseous components were also analyzed to find its suitability as a fuel.

Incidence and patterns of valvular heart disease in a tertiary care high-volume cardiac center: a single center experience.

BACKGROUND: Diseases of the heart valves constitute a major cause of cardiovascular morbidity and mortality worldwide with rheumatic heart disease (RHD) being the dominant form of valvular heart disease (VHD) in developing nations. The current study was undertaken at a tertiary care cardiac center with the objective of establishing the incidence and patterns of VHD by Echocardiography (Echo). METHODS: Among the 136,098 first-time Echocardiograms performed between January 2010 and December 2012, an exclusion criterion of trivial and functional regurgitant lesions yielded a total of 13,289 cases of organic valvular heart disease as the study cohort. RESULTS: In RHD, the order of involvement of valves was mitral (60.2%), followed by aortic, tricuspid and pulmonary valves. Mitral stenosis, predominantly seen in females, was almost exclusively of rheumatic etiology (97.4%). The predominant form of isolated MR was rheumatic (41.1%) followed closely by myxomatous or mitral valve prolapse (40.8%). Isolated AS, more common in males, was the third most common valve lesion seen in 7.3% of cases. Degenerative calcification was the commonest cause of isolated AS (65.0%) followed by bicuspid aortic valve (BAV) (33.9%) and RHD (1.1%). Multiple valves were involved in more than a third of all cases (36.8%). The order of involvement was MS + MR > MS + AR > MR + AR > AS + AR > MR + AS > MS + AS. Overall, 9.7% of cases had organic tricuspid valve disease. CONCLUSION: RHD contributed most to the burden of VHD in the present study with calcific degeneration, myxomatous disease and BAV being the other major forms of VHD. Multiple valves were affected in more than a third of all cases.

Balloon mitral valvotomy in patients with mitral stenosis and left atrial thrombus.

OBJECTIVES: To evaluate the safety and efficacy of balloon mitral valvotomy (BMV) in symptomatic rheumatic mitral stenosis (MS) patients with left atrial (LA) thrombus and to address the technical issues. BACKGROUND: LA thrombus in patients with MS has long been regarded as a contraindication for BMV. There are few reports of BMV in presence of LA appendage (LAA) thrombus and reports of BMV in presence of LA body thrombus are still rare. METHODS: 2,763 patients with suitable valve morphology were screened for BMV. 194 patients had LA/LAA thrombus and were put on adequate anticoagulation for 8-12 weeks. A total of 108 patients with persistent LA thrombus who satisfied the inclusion criteria (LA thrombus type Ia, Ib, and IIa) formed the study group and the remaining 2,622 patients who did not have any LA thrombus constituted the control group. All patients in the study group underwent BMV by modified over the wire technique. RESULTS: There was significant and comparable improvement in the mitral valve area, mitral valve gradient, LA mean and pulmonary artery systolic pressure following the procedure in both groups. In the study group, there were no thromboembolic episodes during the procedure. However, there was one case of transient ischemic attack in the study group which occurred 6 hr after a successful BMV. In the study group, one patient had cardiac tamponade needing aspiration and there was no in-hospital death. CONCLUSIONS: In selected patients of mitral stenosis with LA thrombus (type Ia, Ib, and IIa), BMV can be performed safely with the modified over the wire technique. Systemic thromboembolism, technical failures and other complications are very rare when performed by experienced operators.

Transesophageal Doppler echocardiographic study of pulmonary venous flow pattern in severe mitral stenosis and the changes following balloon mitral valvuloplasty.

The studies of pulmonary venous flow-pattern in mitral stenosis (MS) have given conflicting data about the type of abnormality. This study was undertaken to assess the pulmonary venous flow-pattern in severe MS and to study the changes occurring after balloon mitral valvuloplasty (BMV). There were 51 patients of MS with sinus rhythm with the mean age of 32.5+/-9.35 years, 18 males and 33 females. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were performed before and after BMV. Pulmonary venous flow was recorded by TEE from left upper pulmonary vein (PV). Peak velocities (V) and velocity time integrals (VTI) of systolic wave (S), diastolic wave (D), and atrial reversal wave (A) were measured. The S(v)/D(v) and S(VTI)/D(VTI) were calculated. Mitral valve area (MVA) increased from 0.81+/-0.18 cm(2) to 2.02+/-0.46 cm(2), left atrium (LA) mean decreased from 28.55+/-6.68 mmHg to 13.88+/-4.89 mmHg, and cardiac output increased from 3.1+/-0.86 L/min to 3.7+/-1.02 L/min. The S, D, and A velocities increased from 33.84+/-13.55 cm/s, 37.24+/-11.55 cm/s, and 20.53+/-6.7 cm/s to 59.86+/-18.25 cm/s, 48.43+/- 12.55 cm/s, and 24. 94+/-9.14 cm/s, respectively. The VTIs of S, D, and A waves increased from 4.88+/-2.24 cm, 6+/-2.45 cm, and 2+/-0.88 cm to 10.46+/-4.23 cm, 8.82+/-3.61 cm, and 2.34+/-1.29 cm, respectively. MS leads to reduction in pulmonary flow velocities during all the phases. Successful BMV resulted in improvement of all these velocities, with improvement in systolic fraction being the maximum. These improved flows after BMV appear to be secondary to reduction in LA pressure and improved cardiac output.

Balloon mitral valvuloplasty: our experience with a modified technique of crossing the mitral valve in difficult cases.

The efficacy and safety of percutaneous transvenous mitral commissurotomy performed by the Inoue technique is well known. In cases with critical mitral stenosis and when there is abnormal bulge of the interatrial septum, the usual direct method of crossing the mitral valve may not be successful. In such cases alternative over-the-wire techniques to cross the mitral valve have been advocated by various authors. In this report of 32 cases, we present our experience with the modified and simplified version of over-the-wire technique of crossing the mitral valve in technically difficult cases. This technique involves direct positioning of a pigtail Inoue wire into the left ventricle through the Mullin sheath followed by introduction of an Inoue catheter over the wire. The mitral valve could be crossed in 30 cases (93.75%). There were no major complications attributable to this technique. Frequent ventricular premature beats (100%) and episodes of nonsustained ventricular tachycardia (90%) were seen in most of the cases. We conclude that our modification of the over-the-wire technique is safe, effective, and does not require any additional accessories. Using this technique, percutaneous transvenous mitral commissurotomy could be performed, even in difficult cases wherein the conventional method of crossing the mitral valve has failed.