Physico-mechanical properties of coir fiber/LDPE composites: Effect of chemical treatment and compatibilizer

Nirupama Prasad,Vijay Kumar Agarwal,Shishir Sinha 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.12

Coir fiber/low density polyethylene (LDPE) composites were fabricated with different fiber loading (10- 30 wt%) using compression molding technique. A fiber loading of 20 wt% was found optimum, with maximum mechanical properties. Further, the effect of fiber treatment (alkali and acrylic acid) and compatibilizer (MA-g-LDPE) incorporation on the mechanical and water absorption properties of the LDPE composites were studied and compared. The results showed that MA-g-LDPE incorporation into untreated and treated fiber composites led to improved mechanical properties and water resistance compared with the same composite formulation without MA-g-LDPE. However, treated fiber composites with MA-g-LDPE showed lower mechanical properties than untreated fiber without MA-g- LDPE, due to the removal of hydroxyl groups from the hemicellulose and lignin region of the fiber and degradation of fibers by chemical attack. From SEM studies on the tensile fractured composite samples, a good relationship has been observed between the morphological and mechanical properties.

Effect of oxygen partial pressure on the structural and optical properties of dc reactive magnetron sputtered molybdenum oxide films

V. Nirupama,K.R. Gunasekhar,B. Sreedhar,S. Uthanna 한국물리학회 2010 Current Applied Physics Vol.10 No.1

Molybdenum oxide films (MoO3) were deposited on glass and crystalline silicon substrates by sputtering of molybdenum target under various oxygen partial pressures in the range 8 × 10-5–8 × 10-4 mbar and at a fixed substrate temperature of 473 K employing dc magnetron sputtering technique. The influence of oxygen partial pressure on the composition stoichiometry, chemical binding configuration, crystallographic structure and electrical and optical properties was systematically studied. X-ray photoelectron spectra of the films formed at 8 × 10-5 mbar showed the presence of Mo6+ and Mo5+ oxidation states of MoO3 and MoO3-x. The films deposited at oxygen partial pressure of 2 × 10-4 mbar showed Mo6+ oxidation state indicating the films were nearly stoichiometric. It was also confirmed by the Fourier transform infrared spectroscopic studies. X-ray diffraction studies revealed that the films formed at oxygen partial pressure of 2 × 10-4 mbar showed the presence of (0 k 0) reflections indicated the layered structure of α-phase MoO3. The electrical conductivity of the films decreased from 3.6 × 10-5 to 1.6 × 10-6 Ω-1 cm-1, the optical band gap of the films increased from 2.93 to 3.26 eV and the refractive index increased from 2.02 to 2.13 with the increase of oxygen partial pressure from 8 × 10-5 to 8 × 10-4 mbar, respectively.

Survey on Digital Watermarking Techniques

Deepti Shukla,Nirupama Tiwari 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.9

This paper presents a literature survey on Digital Watermarking within an image. It describes the early work carried out on digital watermarks, including the brief analysis of various watermarking schemes and its applications. This paper also makes a comparison between various watermarking schemes .This paper also gives us a brief introduction about the procedure of digital watermarking.

A Survey of Digital Image Tampering Techniques

Nishtha Parashar,Nirupama Tiwari,Deepika Dubey 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.2

Due to powerful computers and advanced photo-editing software tools the manipulation of images has become an easy task. Confirming the authenticity of images and detecting tampered regions in an image without any knowledge about the image content is an important part of the research field. An effort is made to survey the recent advancements being made in the field of digital image forgery detection and thus passive methods for forgery detection are being presented. Blind or passive methods do not require any explicit former information about the image. In the first part, various image forgery detection techniques are classified and then an overview of passive image authentication is presented and the existing blind forgery detection techniques are reviewed

Survey on Digital Watermarking Techniques

Deepti Shukla,Nirupama Tiwari,Deepika Dubey 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.1

This paper presents a literature survey on Digital Watermarking within an image. It describes the early work carried out on digital watermarks, including the brief analysis of various watermarking schemes and its applications. This paper also makes a comparison between various watermarking schemes .This paper also gives us a brief introduction about the procedure of digital watermarking.

Assessment of Perinatal Clinical Characteristics, Perinatal Risk Factors, and Microbial Profile in Congenital Nasolacrimal Duct Obstruction in a Tertiary Care Center: A Descriptive Study

Kaviyapriya Natarajan,Nirupama Kasturi,Sujatha Sistla 대한안과학회 2022 Korean Journal of Ophthalmology Vol.36 No.4

Purpose: To assess the perinatal risk factors, clinical characteristics, and microbial profile in congenital nasolacrimal duct obstruction(CNLDO). Methods: A prospective observational study was conducted in pediatric patients of age <5 years. After a thorough clinical evaluation, the diagnosis of the CNLDO was confirmed by a Jones dye test or fluorescein dye disappearance test. A microbiological culture of lacrimal sac resurge was done with a sterile swab stick without touching the lid margins. Antibiotic susceptibility was then performed for the standard antibiotics. Results: Seventy-one eyes of 52 children were included in the study. The mean age was 3.4 months. Our research found an equal number of cases born via spontaneous vaginal delivery and Caesarean section. Nine children (17.3%) had associated systemic and ocular anomalies. The number of cultures that were positive for any growth was 19 (27%). The most common isolate was Streptococcus pneumoniae which constituted eight cases (42%), followed by Pseudomonas aeruginosa (15.8%), and Escherichia coli (10.5%). Other organisms that grew were Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and nonfermenting gram-negative bacilli. Gram-positive organisms were susceptible to ciprofloxacin, amoxiclav, and oxacillin, and most of them were resistant to erythromycin. In comparison, gram-negative organisms showed 62.5% resistance and 37.5% susceptibility to ciprofloxacin. Conclusions: CNLDO was more commonly unilateral, in male, preterm, and normal birth weight infants. Bilateral CNLDO was more commonly associated with coexisting ocular or systemic anomalies. Prematurity, delivery by Caesarean section, and presence of congenital anomalies were associated with a prolonged course. S. pneumoniae was the predominant isolate in our patient population.

Ocular Manifestations of Venomous Snake Bite over a One-year Period in a Tertiary Care Hospital

Praveen Kumar K V,Praveen Kumar S,Nirupama Kasturi,Shashi Ahuja 대한안과학회 2015 Korean Journal of Ophthalmology Vol.29 No.4

Purpose: Ocular manifestations in snake-bite injuries are quite rare. However, the unusual presentations, diagnosis and their management can pose challenges when they present to the ophthalmologist. Early detection of these treatable conditions can prevent visual loss in these patients who are systemically unstable and are unaware of their ocular condition. To address this, a study was conducted with the aim of identifying the various ocular manifestations of snake bite in a tertiary care center. Methods: This is a one-year institute-based prospective study report of 12 snake bite victims admitted to a tertiary hospital with ocular manifestations between June 2013 to June 2014, which provides data about the demographic characteristics, clinical profiles, ocular manifestations, and their outcomes. Results: Twelve cases of snake bite with ocular manifestations were included of which six were viper bites, three were cobra bites and three were unknown bites. Six patients presented with bilateral acute angle closure glaucoma (50%), two patients had anterior uveitis (16.6%) of which one patient had concomitant optic neuritis. One patient had exudative retinal detachment (8.3%), one patient had thrombocytopenia with subconjunctival hemorrhage (8.3%) and two patients had external ophthalmoplegia (16.6%). Conclusions: Bilateral angle closure glaucoma was the most common ocular manifestation followed by anterior uveitis and external ophthalmoplegia. Snake bite can result in significant ocular morbidity in a majority of patients but spontaneous recovery with anti-snake venom, steroids and conservative management results in good visual prognosis.

Frequency of group A rotavirus with mixed G and P genotypes in bovines: predominance of G3 genotype and its emergence in combination with G8/G10 types

Yashpal S. Malik,Kuldeep Sharma,Nirupama Vaid,Somendu Chakravarti,K. M. Chandrashekar,Sanjay S. Basera,Rashmi Singh,Minakshi,Gaya Prasad,Baldev R. Gulati,Kiren N. Bhilegaonkar,Awadh B. Pandey 대한수의학회 2012 JOURNAL OF VETERINARY SCIENCE Vol.13 No.3

The present study describes the genotypic distribution of rotaviruses (RVs) in an Indian bovine population with unexpectedly higher proportions of G3 alone or in combination of G8/G10. PCR-genotyping confirmed that 39.4% (13/33) of the prevalent RVs were the G3 type while 60.6% (20/33) were dual G3G10 or G3G8 types. P typing revealed that 93.9% (31/33) of the samples were P[11] while 6.1% (2/33) possessed a dual P[1]P[11] type. Sequence analysis of the VP7 gene from G3 strains viz. B-46, 0970, and BR-133 showed that these strains had sequence identities of 90.5% to 100% with other bovine G3 strains. The highest identity (98.9% to 100%) was observed with RUBV3 bovine G3 strains from eastern India. The G3 strains (B-46, 0970, and BR-133) showed 97.5% to 98.8% sequence homologies with the Indian equine RV strain Erv-80. Phylogenetic analysis demonstrated that G3 strains clustered with bovine RUBV3 and J-63, and equine Erv-80 G3. Overall, these results confirmed that the incidence of infection by RVs with the G3 genotype and mixed genotypes in the bovine population was higher than previously predicted. This finding reinforces the importance of constantly monitoring circulating viral strains with the G3 genotype in future surveillance studies.

전기방사를 이용한 PEO 나노섬유 제조

김길태 ( G. T. Kim ),안영철 ( Y. C. Ahn ),이재근 ( J. K. Lee ),성창모 ( C. M. Sung ),( Nirupama Kattamuri ) 한국분무공학회 2003 한국액체미립화학회지 Vol.8 No.2

N/A Polymeric fibers with nanometer-scale diameters are produced by electrospinning method. When the electrical forces at the surface of a polymer solution or melt overcome the surface tension, then electrospinning occurs and nanofibers are made. Polyethylene oxide(PEO) have been electrospun in our laboratory. Electrospun PEO fibers are observed by scanning electron microscopy or transmission electron microscopy. In this study, the average diameter of the electrospun fibers decreases with decreasing PEO concentration and increasing electric field strength. The optimal conditions for pruducing uniform PEO 100 ㎚ fibers are the 10 wt% PEO concentration at a voltage 25 to 30 ㎸ and a distance of 10 ㎝ from tip to collector.