Measurement of the lower canine pulp chamber through periapical radiography for age estimation

Objectives: The principle of measurement using the TCI (Tooth Coronal Index) method is to compare the pulp chamber height with a person's chronological age based on the formation of secondary dentin. The purpose of this study is to estimate age based on pulp chamber height in lower canines using periapical radiographs with TCI measurement. Materials and Methods: This study is an observational analytic study using 42 samples of periapical radiographs with the parallel technique of the lower canines. Samples were measured for CH and CPCH heights to determine TCI values and then linear regression was made to determine their biological age. Finally, the difference between biological and chronological age is calculated to determine the approximate age. Results: The mean difference between chronological age and biological age was ± 5.05 years and an average biological age of 29.38 years. Conclusion: TCI method based on pulp chamber height in lower canines using periapical radiographs can be used to estimate age with the difference between chronological age and biological age of ±5.05 years.

Bulk-surface coupling identifies the mechanistic connection between Min-protein patterns in vivo and in vitro

Self-organisation of Min proteins is responsible for the spatial control of cell division in Escherichia coli, and has been studied both in vivo and in vitro. Intriguingly, the protein patterns observed in these settings differ qualitatively and quantitatively. This puzzling dichotomy has not been resolved to date. Using reconstituted proteins in laterally wide microchambers with a well-controlled height, we experimentally show that the Min protein dynamics on the membrane crucially depend on the micro chamber height due to bulk concentration gradients orthogonal to the membrane. A theoretical analysis shows that in vitro patterns at low microchamber height are driven by the same lateral oscillation mode as pole-to-pole oscillations in vivo. At larger microchamber height, additional vertical oscillation modes set in, marking the transition to a qualitatively different in vitro regime. Our work reveals the qualitatively different mechanisms of mass transport that govern Min protein-patterns for different bulk heights and thus shows that Min patterns in cells are governed by a different mechanism than those in vitro.

Modelling of a Heated Gas-solid Fluidised Bed using Eulerian Based Models

ABSTRACT An Eulerian-Eulerian granular model was used to simulate the flow and heat transfer through a heatedgassolid fluidised bed. The primary objective of the study was to determine whether the Eulerian-Eulerian granular model adequately predicts the chamber pressure drop, temperature, and bed expansion through the bed. The model predictions were assessed and validated for various flow-regimes, namely the fixed-bed, smooth, bubbling fluidisation, and the maximum fluidisation regimes. This was done on an experimental scale heated gas-solid fluidised bed. However, the results are generalisable for heated gas-solid fluidised beds when the flow is laminar. Numerical models were created using Computational Fluid Dynamics (CFD). The CFD-model predictions were investigated, analysed, and compared to experimental results. Basic experiments were carried out to obtain varying hydrodynamic characteristics. The results showed a slight overprediction of pressure drop and bed expansion, however, the results were still in close agreement with the experiment. In contrast, underprediction of chamber temperatures were obtained. Based on the results of this study, it is recommended that the Eulerian model be used to predict dynamic flow behaviour. Before minimum fluidisation, when in a fixed bed regime, pressure drop in the chamber increases with no increase in bed height. No visible bubbles were present in the fixed bed regime. When fluidisation has been reached, the bed height rises whereas the pressure drop tends to a constant value. Bubble size increases with chamber height and increased superficial velocities. Bubble speed increased with increased chamber height. With increased superficial velocity, the chamber temperatures increase to a maximum temperature of326.65 K with an initial heating element temperature of373.15 K. However, when excessive heat is present in the gas-solid fluidised bed, other methods that sufficiently incorporate particle-particle interactions and bubble-bubble interactions, are recommended. An investigation should be lent to bubble-bubble interactions in the fluidised beds with relation to heat transfer. Additional keywords: Heated fluidised bed, computational fluid dynamics, CFD, Eulerian, granular, fluidisation, gas-solid

Experimental Analysis of Thermal Efficiency of Mud Improved Cookstove With Variation of Different Parameters and Economic Analysis

Most of the rural people of Nepal use fuelwood for cooking and space heating in residential sector. Government of Nepal has announced to make Nepal as a smokeless country by replacing traditional cookstoves. Two pot mud improved cookstove is one of the most promoted cookstoves in the context of Nepal. There is a need to study the effects of different parameters on mud improved cookstove for its better performance. The objective of this work is to study the effect of variation of different parameters on two pot mud ICS and identify parameters for its better performance. Power test of cookstove, specially focusing on thermal efficiency, has been performed by changing different parameters. Effect of varying fuel feeding rate, chimney height, opening area of air fuel inlet, inlet area of interconnecting tunnel, combustion chamber height, grate height and insulating material on thermal efficiency have been studied individually. Then cookstove has been developed by different best combinations such as a) geometrical parameters b) use of grate and insulations in best geometrical parameters and formation of channel on the opening. Thermal efficiency of modified cookstove increased from 18% to 25.6%; i.e. the increment of 7.60%. Economic analysis of different thermal efficiencies cookstove has been performed.

Numerical Simulation for the Combustion Chamber of a Reference Calorimeter

This paper focuses on the numerical modeling of the effect of the height of a combustion chamber on the development of a reference calorimeter whose objective is to measure the calorific value of natural gas. The impacts of temperature, velocity, and mass fraction on the exhaust gases were evaluated by varying the height of the combustion chamber. The eddy dissipation concept (EDC) approach was used to model combustion with two different chemical kinetic mechanisms: one with three steps, called the three-step mechanism defined by default in the software used, and second skeletal model, which consists of 41 steps, through the ChemKin-import file with 16 species. The main result of this study is the selection of a combustion chamber height for the reference calorimeter that produces the best performance in the combustion process, which is 70 mm, as well as the main differences in using a three-step mechanism and a skeletal model to simulate an oxy-fuel combustion reaction.

A simplified model for understanding the performance of two-pot enclosed mud cookstoves

The objective of this study is to develop a mathematical model for a two-pot enclosed mud cookstove. A new model has been developed combining transient heat transfer, combustion chemistry and fluid flow. The model can be used for variation of the operation and design parameters. The model predicts performance parameters such as efficiency, boiling time, excess air ratio (EAR), transient wall, flame and char temperature. For an input power of 5.1 kW, the estimated overall efficiency, EAR and boiling time were 17.1%, 1.97 and 43 minutes, respectively. The model outcome is compared with experimental results. Further, 10 parameters are varied and their impact on cookstove performance is analysed. The optimum dimension for the door opening, combustion-chamber height and wall thickness are suggested. Therefore, this study can serve as an effective tool for cookstove design.

A Piezoelectric Resonance Pump Based on a Flexible Support

Small volume changes are important factors that restrict the improvement of the performance of a piezoelectric diaphragm pump. In order to increase the volume change of the pump chamber, a square piezoelectric vibrator with a flexible support is proposed in this paper and used as the driving unit of the pump. The pump chamber diaphragm was separated from the driving unit, and the resonance principle was used to amplify the amplitude of the pump diaphragm. After analyzing the working principle of the piezoelectric resonance pump and establishing the motion differential equation of the vibration system, prototypes with different structural parameters were made and tested. The results show that the piezoelectric resonance pump resonated at 236 Hz when pumping air. When the peak-to-peak voltage of the driving power was 220 V, the amplitude of the diaphragm reached a maximum value of 0.43933 mm, and the volume change of the pump was correspondingly improved. When the pump chamber height was 0.25 mm, the output flow rate of pumping water reached a maximum value of 213.5 mL/min. When the chamber height was 0.15 mm, the output pressure reached a maximum value of 85.2 kPa.

TREATMENT EFFECTIVENESS EVALUATION OF WASTEWATER FROM INDUSTRIAL FRIED CHICKEN RE- PROCESSING PROCESSES BY ADVANCED OXIDATION PROCESSES

The experiment was conducted by using ozone and graphite electrodes to treat wastewater from industrial fried chicken re-processing peocesses with COD value ranges of 1600 - 2000 mgO2/L. A chamber of 20 liters was used in this study. The chamber height was 1 meter (the high response of 50-60 cm) in order to increase the diffusion of ozone into the wastewater. The study results showed that the amount of ozone needed for the reaction is 300 mg/h with COD removal efficiency of 40 % during reaction time of 45-60 minutes.The rate of BOD/COD increased within 1.55 - 1.80 times as compared with the BOD/COD rate of the initial wastewater. The experiments also showed that the COD removal efficiency of wastewater was not affected much by the pH value of the wastewater.