Orifice enabled flow stabilization of natural circulation loop at lower inclinations

Natural circulation loop (NCL) is mainly used as passive cooling system in nuclear power plants to ensure safety during pump failure and station blackout. Stable operation without flow instability is the most desirable operational mode of natural circulation loop for passive cooling. The present work deals with numerical analysis on the effect of inclination of horizontal leg of a rectangular loop working in single phase and presence of orifice on the thermohydraulic behaviour of NCL, using commercial CFD code ANSYS FLUENT 19.0. The effect of temporal variation of loop mass flow rate and temperature difference across the cooler section is compared for inclined loop with and without orifice. It is observed that the flow stability attained in the loop at inclination h = 308 can be achieved at h = 108 with orifice, with a reduction in the loop mass flow rate of 28.57%. The reduction in loop mass flow rate is accompanied by an increase in temperature difference across the cooler of 46.67%.

Empowerment of Anganwadi Workers in Oral Health Care: A Kerala Experience

Introduction

Aim

Materials and methods

Result

Conclusion

Clinical significance

How to cite this article

Prevalence, Characteristics, and Complications of Supernumerary Teeth in Nonsyndromic Pediatric Population of South India: A Clinical and Radiographic Study

Introduction:

Supernumerary teeth are the presence of more number of teeth over the normal dental formula and may occur in permanent as well as early mixed dentition. This study determined the prevalence, characteristics, and complications caused by supernumerary teeth in nonsyndromic South Indian pediatric population.

Materials and Methods:

Characteristics of supernumerary teeth determined by clinical and radiographic examination were recorded. The age, sex, number of supernumerary teeth, eruption status, morphology, position, orientation, and complications (if any) associated with supernumerary teeth were recorded for each patient who had supernumerary teeth. The data collected were statistically analyzed.

Results:

Supernumerary teeth were detected in 45 subjects (1.1%), of which 34 (75.6%) were male and 11 (24.4%) were female. There was no association between the number of supernumerary teeth and the gender of the patient. The total number of supernumerary teeth among the affected 45 patients was 54. The average number of supernumerary teeth per person was 1.2. The number of supernumerary teeth was one in 35 cases, two in 8 cases, and 3 in 1 case. Of the 45 patients, 8 patients with supernumerary teeth were in deciduous dentition stage, 29 patients were in mixed dentition stage, and 8 patients were in permanent dentition stage. Most supernumerary teeth presented in the anterior maxilla. Morphologically, conical-shaped supernumerary teeth were the most common finding. 68.5% of supernumerary teeth presented with straight orientation and inverted orientation was seen in 24.1%. Complications seen in patients with supernumerary teeth were delayed or noneruption of adjacent tooth malposition or rotation of adjacent teeth, diastema formation, and formation of dentigerous cyst.

Conclusions:

Supernumerary teeth have an incidence of 1.1% in South Indian population and can cause many complications that can harm the developing occlusion. Knowledge about supernumerary teeth may help the dentist in early diagnosis and early intervention.

ASPEN plus modelling of air–steam gasification of biomass with sorbent enabled CO2 capture

The work deals with the modelling and simulation of carbon dioxide capture in air–steam gasification of saw dust using ASPEN Plus process simulator. The proposed quasi-steady state model incorporates pyrolysis, tar cracking and char conversion using existing experimental data. Prediction accuracy of the developed model is validated by comparing with available experimental results. Effects of CaO addition in air–steam gasification are analysed through key operating parameters such as gasification temperature, equivalence ratio, steam to biomass ratio and gasification efficiency. Maximum H2 mole fraction of 31.17% is obtained at a temperature of 900 K, equivalence ratio of 0.25, and steam to biomass ratio and sorbent to biomass ratio of unity. The H2 and CO2 mole fractions are found to be increased and decreased by 28.10% and 42.6%, respectively, when compared with the corresponding non- sorbent case.

Evaluation of the effects of manuka honey on salivary levels of mutans streptococci in children: a pilot study

BACKGROUND

There has been much debate in the past about whether honey is harmful to the teeth, mostly as part of the debate about raw sugar versus refined sugar and the results have been equivocal. However, what has not been taken into account is that honey varies markedly in the potency of its antibacterial activity. Manuka (Leptospermum scoparium) honey from New Zealand has been found to have substantial levels of non-peroxide antibacterial activity associated with an unidentified phytochemical component, denoted as Unique Manuka Factor (UMF).

AIMS

Considering the potential antimicrobial effects of manuka honey, the present study attempted to investigate effects of twice daily use of manuka honey with UMF 19.5 on salivary levels of Mutans streptococci in children.

STUDY DESIGN

The investigation was a stratified comparison of two parallel groups of children who either used manuka honey with regular tooth brushing regimen or continued only with regular tooth brushing regimen twice daily under professional supervision for a 21-day period. A total of three salivary samples were taken from each individual at baseline, day 10, and day 21; colony counts of Streptococcus mutans (S. mutans) were determined. All data was subjected to paired T-test and Wilcoxon's signed ranks sum for intra- and intergroup comparisons respectively.

RESULTS

Children using manuka honey showed statistically significant reductions in salivary S. mutans after 10 and 21 days.

CONCLUSION

Manuka honey with UMF 19.5 may be considered as an effective adjunctive oral hygiene measure for reducing colony counts in children.

The comparative evaluation of the effects of tongue cleaning on existing plaque levels in children

The present study compared and evaluated the effects of tongue scraping and tongue brushing on existing plaque levels in children. The investigation was a single blind, stratified comparison of three parallel groups of children who performed either tongue scraping or tongue brushing along with tooth brushing or only tooth brushing twice daily under professional supervision for a 21 day period. Dental plaque was recorded using the plaque index described by Silness and Loe at baseline, on day 10 and on day 21. All data was subjected to statistical analysis using Wilcoxon's Signed Ranks Sum Test and Mann-Whitney U-test. The results of the present study show that the tongue scraping and tongue brushing groups showed statistically significant reductions in plaque levels after 10 days and also after 21 days. It was also noted that both tongue scraping and tongue brushing were equally effective in reducing the plaque load in children.

How to cite this article: Winnier JJ, Rupesh S, Nayak UA, Reddy V, Rao AP. The Comparative Evaluation of the Effects of Tongue Cleaning on Existing Plaque Levels in Children. Int J Clin Pediatr Dent 2013;6(3):188-192.

The comparative evaluation of the effects of tongue cleaning on salivary levels of mutans streptococci in children

OBJECTIVES

The study compared and evaluated the effects of tongue scraping and tongue brushing on salivary mutans streptococci levels in children.

METHODS

The investigation was a single-blind, stratified comparison of three parallel groups of children who performed either tongue scraping or tongue brushing along with tooth brushing or only tooth brushing twice daily under professional supervision for a 21-day period. A total of three saliva samples were taken from each individual, at baseline, on day 10 and on day 21, and colony counts of mutans streptococci were determined. All data were subjected to statistical analysis using Wilcoxon's signed-ranks sum test and Mann-Whitney U-test.

RESULTS AND CONCLUSIONS

The results of the present study show that tongue scraping and tongue brushing demonstrated statistically significant reductions in salivary mutans streptococci counts after 10 days and also after 21 days. It was also noted that tongue scraping and tongue brushing were equally effective in reducing colony counts.

The relationship of two orthodontic indices, with perceptions of aesthetics, function, speech and orthodontic treatment need

PURPOSE

The study was conducted to evaluate the relationship between the Dental Aesthetic Index (DAI) and Index of Orthodontic Treatment Need (IOTN) with subjective perceptions of dental aesthetics, function, speech and orthodontic treatment need.

METHODS

This is an observational cross-sectional study. The children were assessed using the DAI and IOTN. A questionnaire pertaining to dental aesthetics and function was recorded.

RESULTS AND CONCLUSIONS

The aesthetic components of the indices correlated well with aesthetic perceptions of patients, whereas functional components did not have a significant correlation with functional perceptions. The two indices could be used consistently in the present population.

Comparative evaluation of the effects of an alum-containing mouthrinse and a saturated saline rinse on the salivary levels of Streptococcus mutans

BACKGROUND

The literature is replete with studies establishing Streptococcus mutans as a major player in the formation of pit and fissure caries in all dentitions. Salivary bacterial levels in turn are related to the number of colonized surfaces. Therefore, decreasing the salivary levels of S. mutans would have a great benefit in decreasing the incidence of dental diseases.

AIMS

Keeping in mind the potential antimicrobial effects of saturated saline and alum solutions, the present study was attempted to compare and evaluate the effects of saturated saline rinse and 0.02 M alum mouthrinse on salivary S. mutans levels in children.

MATERIALS AND METHODS

The investigation was a double-blind, stratified comparison of three parallel groups of children who used either saturated saline rinse, 0.02 M alum mouthrinse or distilled water (placebo) rinse twice daily under professional supervision for a 21-day period. A total of three saliva samples were taken from each individual - at baseline, on the 10 th day and on the 21 st day, and colony counts of S. mutans were determined. All data were subjected to statistical analysis using Wilcoxon's Signed Ranks Sum and Mann-Whitney "U" test.

RESULTS AND CONCLUSIONS

Children using saturated saline rinse and alum rinse showed statistically significant reductions in salivary S. mutans counts after 10 days and also after 21 days. After 21 days, the saturated saline rinse and alum rinse groups showed statistically significant differences over the placebo rinse group. Again, the alum rinse group showed a statistically significant difference over the saturated saline rinse group.

Genetic sensitivity to the bitter taste of 6-n propylthiouracil: a new risk determinant for dental caries in children

The aims of the present study were to contrast the prevalence of dental caries in children with different genetic sensitivity levels to the bitter taste of 6-n-propylthiouracil (PROP) and to determine the taste quality and taste intensity preferences of food products among the taster and nontaster groups. Overall caries experience (dmfs/DMFS) was significantly higher for nontasters than tasters. Caries experience on the available surfaces (dfs/DFS) was found to be significantly higher in nontasters than in medium tasters and in medium tasters than in supertasters (r=-0.41, P < 0.001). Majority of the nontasters were sweet likers and preferred strong tasting food products, while majority of the supertasters were sweet dislikers and preferred weak tastes. There was a significant increase in the overall caries experience in the population, as the genetic ability to detect PROP taste decreased ( P < 0.001). After all associated factors (age, gender, race, number of teeth and OHI-S) were controlled; multiple linear regression analyses revealed that taste was the only variable significantly related to overall caries experience.