Machining of polymeric composite is inevitable during assembly of components. In view of making holes on structural composites, drilling is essential and a study to optimize the machining parameters ...is very important. The present study has been made to investigate the defaces and cutting forces associated during drilling of natural fiber reinforced plastics. Plastic composite has been manufactured using chemically treated
vetiveria zizanioides
as the reinforcement and polyester as the matrix. The composite has been drilled several times on the basis of central composite design. Speed and feed rate of the spindle, point angle and diameter of the tool are considered as the input parameters. Deface of each hole during entry and exit, thrust force and torque have been measured as the output parameters. A fuzzy model has been created and a comparative study between the central composite design and fuzzy model is made. The design has been optimized with the objective of minimizing the output parameters and a set of confirmatory experiments have been conducted. The central composite model has been validated by comparing it with the fuzzy model and confirmatory runs. The comparison presented only a minimal error and hence the modeling by central composite design and fuzzy are consummate.
Deposition of tar balls (TBs) along the south Gujarat coast, situated on the west coast of India (WCI), commonly occurs during the southwest monsoon season. Several offshore oil fields off the ...Mumbai–Gujarat coast, and refineries along the coast might be sources of oil spills/leakages and lead to the formation of TBs. To identify the sources, we collected 12 TB samples from the beaches of Gujarat (Tithal, Maroli, Umbergam, and Nargol) during 15–17 July 2012 as well as samples of crude oils, namely, Cairn, NIKO, MSC Chitra, and two at Bombay High (BH). These TBs were subject to the following multimarker approach for source identification: Diagnostic Ratios of n-alkanes, polycyclic aromatic hydrocarbons, pentacyclic triterpanes, compound specific isotope analysis, Principle Component Analysis and numerical simulations (hydrodynamic model coupled with particle trajectories). The chemical fingerprint results reveal that the source of the TBs is BH crude oils, and the model results confirm that the source location is BH north oil fields. This is the first study of its kind in India to use fingerprinting and transport modeling techniques for source identification of TBs.
The need of composite material in industries is increasing day by day due to its competent characteristics with the traditional materials. The plastic composite materials made of polymers are used as ...structural elements in different fields. The present day polymeric composites are made by mainly focussing the natural fibers as reinforcements because of their usability, properties and cost. While preparing these new composites, utmost care must be taken for synthesizing the natural fibers and polymers before fabrication. Also, during the fabrication of a new composite the process and parameter selection plays a vital role. Once the composites are fabricated, it needs several machining operations as secondary processing. This paper gives a detailed review of different challenges during the synthesis, fabrication, characterization and machining of natural fiber reinforced plastic composites.
Dental caries is one of the most common causes of morbidity of the tooth. Attempts have been made to reduce the pathogen population size i.e.,
(MS) to demote the incidence of caries and increase the ...resistance of the tooth to cariogenic attack.
To evaluate the antibacterial efficacy of freshly prepared ozonated water, in proposing it as an alternative mouth rinse on MS in comparison to Chlorhexidine (CHX).
Subjects with high caries incidence and MS counts more than 105 Colony Forming Unit (CFU) were selected and divided by block randomization into two groups of 23 subjects each. The subjects were advised to use the respective mouth rinses under the operator surveillance, consecutively for 14 days. Stimulated salivary samples were collected from the subjects on the first day, 7
and 14
day to analyse the changes in MS counts during the course of use of oral rinses. The obtained data was tabulated and statistically analysed.
Freshly prepared ozonated water showed a statistically significant reduction in MS counts after an interval of 7 days and 14 days when compared to CHX.
Ozonated water when consecutively used as a mouth rinse resulted in a significant reduction of MS counts. Hence, it can be used as an alternative to chlorhexidine.
Basal cell adenocarcinoma (BCAC) is a rare neoplasm accounting for only 2.9% of all salivary gland neoplasms. BCAC involving palatal minor salivary glands are exceedingly rare, and only 10 cases have ...been reported in the literature. The treatment of choice is surgical excision. Here, we report a case of a 55-year-old male patient with massive BCAC of palatal minor salivary gland extending into the maxillary sinus. This is the first case of BCAC treated by radiotherapy followed by chemotherapy. A follow-up check conducted after 14-months showed good prognosis.
Arrival of tar balls to the Goa coast during pre- and southwest monsoon seasons has been a regular phenomenon in the past few years. In one such event, we observed tar ball deposits along the Goa ...coast during August 2010, April 2011 and May 2011 when no oil spill was reported in the Arabian Sea (AS). The only source for the formation of tar balls could be the spill/tanker-wash from the tankers passing through the international tanker routes across the AS. Assuming this, an attempt has been made to simulate surface winds, currents and tar ball trajectories for August 2010 using hydrodynamics and particle tracking models. Tar ball particles were released numerically at eight locations in the AS, and five of them reached the Goa coast, matching reasonably well with the observations. The present study confirms our view that the source of these tar balls is the accidental spills or tanker-wash along the international oil tanker route in the AS. A review of the global scenario of tar ball study is also presented in the Introduction.
The present study's aim was to assess the pattern of palatine ridges/rugae to identify gender.
This study consists of a total of 50 participants (25 males and 25 females). Participants of the age ...range of 20 to 50 years were selected from the outpatient department. According to the shape and size of the patient's arches, maxillary impression trays were selected using alginate, and casts were poured subsequently. With the help of a sharp graphite pencil, the palatine ridges were delineated to make it prominent, and on either side of the midline, the number of rugae was counted and the length measured. Using these parameters, the pattern of rugae was determined. Data were analyzed using independent sample t-test. The level of significance was set at 5%.
Males had more number of palatal rugae (mean 5.96 ± 0.88) compared with females (5.24 ± 0.77), and there was a statistically significant association between them. The mean length of palatal rugae was more in males (6.25 ± 1.15 mm) than females (5.16 ± 1.40 mm), and it was found to be a statistically significant association. The straight pattern was more common in both males and females (2.56 ± 1.08, 2.32 ± 0.85 respectively) than other patterns.
This study concluded that straight rugae pattern has been found to be the most common pattern in both genders. However, the mean number of straight rugae pattern and length is slightly more in males than females.
The most challenging tasks in forensic medicine is human identification. Dental records, dactylogram, and comparing deoxyribonucleic acid are the widely used techniques in mass disasters, but these techniques have their own drawbacks and hence cannot be applied always. In such cases, less known techniques like rugoscopy will be helpful.
S-(+)-Clopidogrel bisulfate (S-(+)-methyl 2-(2-chlorophenyl)-2-(6, 7-dihydrothieno3, 2-cpyridin-5(4H)-yl)acetate bisulfate) is a platelet aggregation inhibitor drug. S-(+)-Clopidogrel bisulfate is ...prepared by different synthetic approaches in the literature. In almost all the approaches the major impurities known in the literature (A, B, and C) are also listed in the U.S. pharmacopoeia. The control of these pharmaceutical impurities is currently a critical issue to the pharmaceutical industry. In this article, a description of these impurities and their origins in the S-(+)-clopidogrel bisulfate process are presented along with the preparation of impurity B.
The silica nanoparticles prepared by stober’s mechanism by reaction of tetraethylorthosilicate (TEOS) with ammonia was tested for their adsorption capacity in the pre-concentration of residues of ...pesticides in water. The synthesized nanoparticles were characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD). The size of the silica nanoparticles were 50 to 250 nm. The solid phase extraction (SPE) cartridges were prepared by filling the empty cartridges of 5.5 cm length and 0.3 cm i.d. with 200 mg of nanoparticles and protected between two polytetrafluroethylene (PTFE) frits. To avoid the passage of nanoparticles, 2% solution of polystyrene in chloroform was passed through PTFE frits and dried in air for two hours at room temperature before fitted into the cartridges. This process is to reduce the pore size of the PTFE frits. These cartridges are used in pre-concentration of different types of residues of pesticides in water. The pyrethroids tested for the pre-concentration are tetramethrin, lambda-cyhalothrin, cyphenothrin. The water samples were spiked with aliquots of pesticides and were passed through the cartridges. The amounts of the pesticides adsorbed on the cartridges were tested. The influence of temperature, sample volume, flow rate, pH and ionic strength on the performance of the cartridges was checked. The results of fortified sample analysis were compared with the data obtained from the commercially available C18 cartridges for the sample volume. The separation parameters were established for the simultaneous determination of residues using GC-EI-MS. The method was validated by means of linearity, precision, and assay accuracy. The limit of detection (LOD) and the limit of quantification (LOQ) were established based on the signal to noise ratio 3:1 and 10:1 respectively. An analytical method for the enrichment of residues using nanoparticles based SPE cartridges were developed and factors influencing the pre-concentration of residues of pyrethroids were studied and reported.
The Suzuki coupling reaction is tremendously flexible to adopt the conditions for wide range of product synthesis. It was first carried out between alkenyl reactants, but over the years, the scope of ...the reaction has been extended to couple carbon atoms in aryl, alkyl, and alkynyl groups under a wide variety of conditions. Commercially available 2-bromo-5-tosyl-5H-pyrrolo2,3-bpyrazine (C1) was treated with pyrimidine derivative in the presence ofBis(triphenylphosphine)palladium(II)dichloride(Pd(C6H5)2Cl2)andTetrakis triphenylphosphine)palladium(0) Pd(C6H5)3P4.The major advantages of Suzuki coupling over other similar reactions are include availability of mild reaction conditions, common boronic acids, and its less toxic nature. When comparing the Boronic with acids organostannane and organozinc compounds ,Boronic with acids found to be less toxic and environment friendly. Docking studies showed all synthesized compounds were interacting with the serine and threonine residues of tyrosine-protein kinase to act as serine/threonine inhibitors.
PDF
