Ordinate Research Articles

A 3D printed positioner for hip rotation center used in total hip arthroplasty

Objective To evaluate the application of a 3D printed positioner for hip rotation center in total hip arthroplasty. Methods From August 2015 to December 2017, 14 patients were treated by unilateral total hip arthroplasty at Department Ⅰ of Joint Surgery, Orthopaedics Hospital of Zhengzhou for avascular necrosis of femoral head or femoral neck fracture. They were 8 males and 6 females with an average age of 51.8 years (from 37 to 65 years). All their surgeries were assisted by a 3D printed positioner for hip rotation center. Postoperatively, the abduction and anteversion of acetabular cup and the hip rotation center were measured, the agreement between the hip rotation center of the affected side (O2) and the anatomical rotation center of the healthy side (O1) was assessed, and the function of the affected hip and complications were recorded at the last follow-up. Results The 14 patients were followed up for an average of 18 months (from 6 to 24 months). The postoperative ordinates of O2 and O1 were respectively 19.36 mm±3.61 mm and 18.33 mm±3.41 mm while their abscissas 39.93 mm±2.97 mm and 39.99 mm±3.16 mm, indicating agreement between O2 and O1 (P>0.05). The postoperative abduction and anteversion of the cup were within a normal range (39.3°±3.2°and 14.6°±1.2°, respectively). The last follow-up showed that their preoperative Harris hip scores (42.3±3.2) were significantly improved (94.3±4.7) (t=2.873, P=0.002) and that 13 cases were rated as excellent and one as good. X-ray follow-up showed good position of their acetabular prostheses, no loosening of the cups or femoral prostheses, and no heterotopic ossification. Conclusion A 3D printed positioner for hip rotation center can effectively assist reconstruction of the hip rotation center and accurate implantation of acetabular prosthesis in total hip arthroplasty. Key words: Arthroplasty, replacement, hip; 3D printing techniques; Center of rotation; Positioner

Experimental Study of Electrical Resistivity to Rock Fracture Intensity and Aperture Size

Fracture geometric characteristics (FGC) such as fracture intensity, fracture network connectivity and aperture distribution are crucial features controlling the hydraulic and geotechnical properties of rock formations. Geophysical methods have been used to detect contrast in subsurface material. The Electrical Resistivity (ER) method is one of such methods. The method was applied in an experimental test to investigate ER response with varying fracture intensity If and aperture size Aper width in an experimental set-up at Kwame Nkrumah University of Science and Technology (KNUST, Kumasi, Ghana, geotechnical laboratory. The concepts of electrical resistivity variation with rock mass fracture intensity, and aperture were used to obtained experimental data. ER profiles, each measuring 0.9 m long were recorded using 4 electrodes deployed using the Dipole-dipole, Wenner and Schlumberger configurations from the experimental setup. To quantify the relationship between apparent resistivity and fracture intensity, scatter-plots were drawn with apparent resistivity as the abscissa and fracture intensity as well as aperture width as ordinate. There were strong positive linear and regressive correlations between ρa and fracture intensity. Mathematical relationships are established that relate the ER and fracture intensity, and ER with aperture width. The highest coefficient of determination R2 of 0.924 was represented for best fit equation, for relationship between apparent resistivity and fracture intensity. For aperture width, the best fit model was given a logarithmic relation as ρa =-465.46(Aperture width)2 +4880.5(Aperture width)+1295.5. The study demonstrates the potential usefulness of the ER approach in rock fracture characterisation investigations, which is economic, efficient and less time consuming compared to other methods, of subsurface fracture characterization such core drilling.

An Algorithm for Labeling Stable Regions of a Class of Time-Delay Systems with Abscissa

Stability is usually in the sense of Lyapunov's asymptotical stability, thus the solutions starting from points close to a stable equilibrium may have a very long transient. In the applications of time-delayed feedback controls, it is important not only to determine the stable regions in the gain plane or gain space, but also to find out the abscissa that can be used as an index of stability. Based on the D-subdivision method, this paper proposes a simple algorithm for finding and labeling the stable regions in feedback gain plane with abscissa.The labeled sub-regions with smaller abscissa are better in applications. The main results are presented for the controlled pendulum or inverted pendulum under a delayed feedback, and are illustrated with two case studies.

Shielding calculations of PWR using JSNT code

Reactor shielding calculations is the foundation for assessing nuclear plant safety performance. It is also an important method to provide guidelines for constructions and operations of nuclear plant. JSNT is a massively parallel discrete ordinates transport code developed by CAEP software center for high performance numerical simulation, with high simulation precision and efficiency. In this paper, a commercial PWR has been modeled and simulated using JSNT code. Flux distributions are obtained and compared with experimental measuring results. Comparisons show that results obtained by both S8 and S16 calculations could satisfy engineering demand. Moreover, in comparison to S8 calculation, S16 could improve the calculation precision significantly and decrease relative errors of some detectors under 1%.

PERAN DPD DAN GAGASAN AMANDEMEN KELIMA UUD 1945

Regional Representative Council (PRC) is a new state institution based on the third amendment of the Constitution 1945. It is regulated in the Stipulation of Atticle22 C and Article 22D of the Constitution 1945. This institution is the substitute of regional and assembly delegations, as we know before. It is only a weak party; however, it has a quite strong power. Therefore, it emerges criticisms that PRC is no more than a group of staffs who are sub ordinate to the Parliament. As a result, it leads to the idea of the next amendment of the Constitution 1945, particularly on the power of pRC. In the reality, there are many disregarded cases dealing with regional autonomy that should be the attention of PRC. Take, for example, managements of regional finances from public allocation funds. as well as from natural resources of the regions. Other cases are poor nutrition, starving, and floods as the result of bad space managements. These cases get only minor attention from PRC' In this case, pRC is considered insensitive to the issues and developments of the regions. Therefore, the Fifth Amendment needs to be taken into account. However, before we go further' we need to prepare the grand design. There should be clear what are being improved. In the end, the amendment wili not be the process of mending or patching only. Yet, the peoples can take the benefits of it.

Effects of dead box 1 gene on cell apoptosis, proliferation and cell cycle of neuroblastoma cells

Objective To explore the effects of dead box 1(DDX1)gene on cell apoptosis, proliferation and cell cycle of neuroblastoma(NB) cells. Methods SK-N-BE(2)/blank, SK-N-BE(2)/shV and SK-N-BE(2)/shDDX1 cells were seeded in 96-well plates, which grew in good condition and in the logarithmic growth phase, 5 000 cells were inoculated in each well and 5 repeated holes were set.Cell count kit 8(CCK-8) was used to detect the cell number at 12 h, 24 h, 36 h, 48 h, and the average was calculated.The time (hour) was set as abscissa, the optimal density (A) value at 450 nm was set as vertical axis, and the growth curves of these 3 cells were drawn to investigate the effects of DDX1 on the proliferation of NB cells.After 24 h, flow cytometry (PI staining) was used to detect the apoptosis of SK-N-BE(2)/blank, SK-N-BE(2)/shV and SK-N-BE(2)/shDDX1 cell lines to observe the effects of DDX1 on the apoptosis of NB cells.After 24 h, flow cytometry (PI staining) was used to detect the proportion of SK-N-BE(2)/blank, SK-N-BE(2)/shV and SK-N-BE(2)/shDDX1 cells at G1, S, M, G2 stage to observe the effects of DDX1 on the cell cycle of NB cells. Results SK-N-BE(2)/shDDX1 cell proliferation was significantly lower than SK-N-BE(2)/blank and SK-N-BE(2)/shV cells, that was to say, DDX1 knockdown reduced the cell proliferation of NB.According to the flow cytometry results, the total average apoptosis rate was 5.28% in SK-N-BE(2)/shV cells, and the total average apoptosis rate was 9.99% in SK-N-BE(2)/shDDX1 cells.The number of apoptotic SK-N-BE(2)/shDDX1 cells was significantly higher than the number of SK-N-BE(2)/blank and SK-N-BE(2)/shV cells, which indicated that DDX1 knockdown increased tumor cell apoptosis of NB.Compared with SK-N-BE(2)/blank and SK-N-BE(2)/shV cells, the cell cycle of SK-N-BE(2)/shDDX1 cells was arrested, and the proliferation was affected. Conclusions After DDX1 expression is inhibited, the cell cycle of NB cells are affected, the cell apoptosis is increased, and the cell proliferation is reduced. Key words: dead box1 gene; Neuroblastoma; Cell cycle; Apoptosis; Proliferation

An Interpretative Phenomenological Analysis of Coping in Rejection Sensitivity

One of the most intense needs in human beings is the need to be accepted by others. This need is severely thwarted among individuals high in rejection sensitivity. Rejection Sensitivity is the disposition to avidly anticipate, recognize and over-react to perceived rejection by others. Quantitative research and experimental observations have long supported a link between self-regulation as a coping mechanism and rejection sensitivity. However less is known about the process of how this comes about and little qualitative research has been conducted in the area. The current study aimed to gain an in depth understanding of the expression of self in countering Rejection Sensitivity. The study focused on the use of Interpretative Phenomenological Analysis (IPA) in order to find super ordinate themes from the account of four women, subjected to a semi-structured interview schedule. Through purposive sampling, the subjects were selected on the basis of being high in rejection sensitivity, having administered the Rejection Sensitivity Questionnaire (Downey & Feldman, 1996) on a sample of twenty-four women. Content Analysis of the transcripts of the interview saw the emergence of 4 major themes. These themes were then interpreted in light of Bandura's Self-efficacy theory. The results suggest-1) personal self-efficacy beliefs have significant implications on psychosocial outcomes in interpersonal situations 2) positive dynamics of self-efficacy emerge as an antecedent to the individual's adjustments in interpersonal relationships following secondary change 3) self-control, an important requisite in countering rejection in RS is founded on self-efficacy. The present findings suggest that the implication of self-efficacy on commitment and confidence work together to increase our persistence in the face of rejection and increase health behaviour by perceiving cues that counter self-fulfilling maladaptive responses to perceived rejection.

An A - train satellite based stratiform mixed - phase cloud retrieval algorithm by combining active and passive sensor measurements, British Journal of Environment and Climate Change, Vol

Aims: To develop a new satellite-based mixed-phase cloud retrieval algorithm for improving mixed-phase cloud liquid water path (LWP) retrievals by combining Moderate Resolution Imaging Spectroradiometer (MODIS), CloudSat, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) measurements. Study Design: Algorithm development and evaluation by using collocated NASA A-Train and the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) measurements at the North Slope Alaska (NSA) site. Place and Duration of Study: Collocated MODIS and ground-based measurements at NSA site from March 2000 to October 2004, MODIS measurements and retrievals during July 2006 over Eastern Pacific, and MODIS, CloudSat and CALIPSO measurements on April 04, 2007 over the Arctic Region. Methodology: The stratiform mixed-phase cloudswere treated as two adjunct water and ice layers for radiative calculations with the Discrete Ordinate Radiative Transfer (DISORT) model. The ice-phase properties were provided with the 2C-ICE product, which is produced from CloudSat radar and CALIPSO lidar measurements, and they were used as inputs in DISORT for the calculations. Then, the calculated mixed-phase cloud reflectances at selected wavelengths were compared with MODIS reflectances to retrieve liquid-phase cloud properties. Results: A new algorithm was developed to retrieve LWP in stratiform mixed-phase Original Research Article British Journal of Environment & Climate Change, 3(4): 587-611, 2013 588 clouds by using MODIS radiances and ice cloud properties from active sensor measurements. The algorithm was validated separately by using Operational MODIS retrievals of warm marine stratiform clouds and collocated surface measurements of Arctic stratiform mixed-phase clouds. The results show that the new algorithm reduced the positive LWP biases in the Operational MODIS LWP retrievals for stratiform mixedphase clouds from 35 and 68% to 10 and 22% in the temperature ranges of -5 to -10oC and -10 to -20oC, respectively. Conclusion: The combined A-Train active and MODIS measurements can be used to improve global mixed-phase cloud property retrievals.

A methodology for applying V–blocks and clamps to non–prismatic workpart fixtures

Most research in computer–aided fixture design (CAFD) aims to develop algorithms to automatically design the fixture configuration of workpieces. Due to the complexity of non–prismatic geometry, the application domain has been mostly limited to prismatic workpiece fixturing. Moreover, based on the 3–2–1 locating principle, the locators employed are mostly restricted to the cylindrical type. This research focuses on another type of fixture configuration for non–prismatic parts that has been mostly overlooked. This is to apply V–blocks in workholding to ensure stable and efficient work setup of non–prismatic parts. The algorithm presented in this paper determines V–block locating by utilising projected geometric reasoning. The major steps of the algorithm include candidate–point generation, angle and distance checking, co–ordinate transformation, and interference analysis. Further more, this paper also explores another algorithm for determining the corresponding clamping location of the V–block. The horizontal clamp is planned based on static principles. To ensure workpiece stability, the planning procedure is classified into three distinct cases according to the force distribution and frictional conditions at the contacting regions. These two algorithms, V–block locating and clamp planning, are applied interactively to obtain the most desired fixture configuration. Finally, an example is provided to explain how these algorithms are applied.

Local discrete velocity grids for deterministic rarefied flow simulations

Most of numerical methods for deterministic simulations of rarefied gas flows use the discrete velocity (or discrete ordinate) approximation. In this approach, the kinetic equation is approximated ...

Metabolism of Salmonella enterica serovar typhi influenced by RpoE and RpoS under hyperosmosis

To study the role of RpoE and RpoS on the influence of the metabolism and growth of bacterial under hyperosmotic stress. The rpoS/rpoE double deletion mutant of Salmonella enterica serovar typhi (S. typhi) was prepared by homologous recombination through the suicide plasmid mediated. The recombination was visualized by PCR. Growth curves were drawn by using photometric value A600 as the ordinate and cultivation time as abscissa. The survival abilities of bacterial were compared under hyperosmotic stress. Statistical differences of early logarithmic growth stage (4 h) and laters logarithmic growth stage (12 h) were analyzed by one-way ANOVA. The expression difference of metabolism related genes of wild-type and mutant strains of S. Typhi incubated under hyperosmotic stress were investigated by Salmonella genomic DNA microarray. Real-time quantitative PCR (qRT-PCR) was performed to validate the results of microarray assay in some selected genes. The rpoS/rpoE double deletion mutant of S. Typhi was successfully generated. The analysis of growth curve showed that the 4-hour and 12-hour A600 values were separately 0.503 ± 0.018 and 2.060 ± 0.112 in rpoS deletion mutant strains, 0.293 ± 0.053 and 1.933 ± 0.115 in rpoE deletion mutant strains, and 0.051 ± 0.007 and 0.963 ± 0.111 in rpoS/rpoE double deletion mutant strains; all of which were lower than the values of wild-type strains, who were 0.725 ± 0.097 and 2.496 ± 0.171, respectively. The difference were statistically significant (P < 0.05). The genomic DNA microarray revealed that 42 genes relevant with bacterial metabolism were influenced by RpoE and RpoS. Results of qRT-PCR showed that the expression values of rpsE, rbsK, nusG and etuB in rpoS deletion mutant strains were (1.86 ± 0.14)×10(6), (1.37 ± 0.11)×10(6), (2.72 ± 0.58)×10(6) and (8.27 ± 1.01)×10(6) copies/µg, respectively; while those in rpoE deletion mutant strains were (2.19 ± 0.17)×10(6), (1.51 ± 0.12)×10(6), (2.73 ± 0.57)×10(6) and (9.63 ± 1.42)×10(6) copies/µg, respectively. Compared with the values in wild-type strains, which were separately (1.94 ± 0.10)×10(6), (1.52 ± 0.11)×10(6), (2.39 ± 0.52)×10(6) and (10.83 ± 1.52)×10(6) copies/µg, the differences was not statistical significance (P > 0.05). However, compared with the values in rpoS/rpoE double mutant strains, which were separately (5.64 ± 0.59)×10(6), (4.17 ± 0.40)×10(6), (9.44 ± 1.22)×10(6) and (2.95 ± 0.88)×10(6) copies/µg, the difference was significant (P < 0.05). RpoE and RpoS could influence the expression of lots of metabolism genes. Together, they regulated the metabolism and growth of S. Typhi under hyperosmotic stress.

Analysis of position of one-piece soft intraocular lens after implantation of intraocular lens with Pentacam

Background The aspheric intraocular lenses(IOLs)can reduce ocular spherical aberration to some degree.However,the clinical effect depends more on the IOL proper alignment.It becomes more important to study the IOL position in eye,Objective This study was to analyze the position alteration of IOL after phacoemulsification combined with implantation of one-piece soft IOLs.Methods In this prospective control study,80 eyes of 40 patients with age-related cataract were enrolled.The phacoemulsification with IOL implantation was performed in all the eyes.Decentration and tilt of IOL in the nasal superior,superior temporal,inferior temporal and nasal inferior quadrants(the intersection point of the system optical axis and the IOL maximum cross plane were regarded as the ordinate origin)were measured by rotating Scheimpflug camera(Pentacam Oculus)in 3 months postoperatively under the mydriasis condition.Written informed consent was obtained from each subject prior to this trial.Results In the right eye group,the IOL decentered toward temporal in 26 eyes(65％)and infratemporal in 16 eyes(40％).IOLs tilted temporally in the horizontal plane in 37 eyes(92.5％)and tilted inferiorly in the vertical plane in 34 eyes(85.0％).In the left eye group,IOLs decentered temporally 33 eyes(82.5％)and 20 IOLs (50％)infratemporally,IOLs tilted temporally in the horizontal plane in 37 eye(92.5％)and 36 IOLs(90％)tilted inferiorly in the vertical plane.There was no statistical difference for the intercomparsion of horizontal/vertical decentration in various quadrant in the right eye(F =0.221,0.792,P＞0.05).The obvious elevated horizontal decentration was found in the supertemporal and infratemporal quadrants compared with supernasal quadrant in the left eyes but there was no significant difference in the vertical decentration among 3 quadrants(F=0.576,P＞0.05).Decentrations were positively correlated with the tilt in both horizontal and vertical plane(right eye horizontal plane:r=0.374,P=0.002;right eye vertical plane:r=0.402,P=0.001 ;left eye horizontal plane:r=0.377,P=0.002；left eye vertical plane:r=0.347,P=0.002).Conclusions The one-piece soft IOLs(Adapt AO)decenter toward temporal mostly in 3 months after surgery,especially infratemporally in the eye.And the optical axis of the IOL tilt toward infratemperol mostly in both right and left eyes.The decentration and tilt are consisted in the corresponding direction between the right and left eyes.The position of the IOLs showed mirror symmetry between right and left eyes.The IOLs decentration show the positively correlation to tilt whatever in horizontal and vertical plane. Key words: Intraocular lens/one-piece soft intraocular lens; Deeentration; Age-related cataract; Phacoemulsification combined with implantation of intraocular lens

Time-relative-intensity curve of contrast-enhanced ultrasonography for discrimination of malignant and benign liver tumors

Objective To study the diagnostic value of relative parameters and time-relative-intensity curve(TRIC) in malignant and benign liver tumors with contrast-enhanced ultrasound(CEUS). Methods Fifty-nine focal liver lesions were examined with CEUS and drawed time-intensity curve(TIC) with QLAB software. The relative parameters of malignant and benign liver tumors were calculated and analysed. The relative intensity equaled the echo intensity of lesion substracted the encho intensity of liver. TRIC were drawed with time as abscissa and relative intensity as the ordinate. The types of TIRC were analysed comparatively in different groups (benign and malignant). Results There were significant differences in relative peak time, relative peak intensity, relative enhancement time and relative decline slope between malignant and benign lesions( P ＜0. 05). TRIC appeared quick-ascending and quick-descending types in the malignant lesions,the decline curve of TRIC droped down to 0 dB at (28.24 ± 8. 14)s and down to lowest - 8 dB continually, meanwhile fluctuated slightly. While TRIC appeared slow-ascending and slow-descending types in the benign lesions, the decline curve of TRIC droped down to the lowest 4 dB continually, meanwhile fluctuated slightly. Conclusions The relative parameters and TRIC are new quantitative indicators of CEUS for diagnosis of malignant and benign liver tumors. Key words: Ultrasonography; Microbubbles; Liver neoplasms

Simulation for the Flowing Water Purification with Spring Shape Inside Chamber

Interest in application of ultraviolet light technology for primary disinfection of potable water in drinking water treatment plants has increased significantly in recent years. The efficacy of disinfection processes in water purification systems is governed by several key factors, including reactor hydraulics, disinfectant chemistry, and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics(CFD) model to predict velocity fields, mass transport, chlorine decay, and microbial inactivation in a continuous flow reactor. In this paper, It describe the how to design optimal UV disinfection device for ground water, BWT and rainwater. Spring shape instrument silver coated located in inner side of disinfection chamber. It make lead the active flowing movement target water and maximize disinfection performance. To search the optimal design method, it was performed computer simulation with 3D-CFD discrete ordinates model and manufactured prototype. Using proposed design method, performed simulation and proved satisfied performance.

APPROACHES IN WIND FIELD MODELING AND AIR QUALITY MONITORING SYSTEMS

There is an increasing interest in the research of methods for measuring, calculation, prediction and estimation of the level of pollutant in ambient air. Wind velocity is a major actor in atmospheric pollutant dispersion, so, together with experimental techniqu es, theoretical wind field models, combined with ad equate interpolation methods, provide important tools for pollution assessment and air quality prediction. Th is paper firstly discusses some basic concepts of the variat ional analysis formalism, as a classic framework fo r wind field models over complex terrains. The discrete version of the variational wind field model in Cartesian co ordinates can be used for interpolation of measured data and prediction of pollutant transport dynamics. The str ucture of an extended air quality monitoring system, integrat ing measurement stations, workstations and wind fie ld model- based software applications, dedicated to construct ion of atmospheric parameters maps, is finally prop osed. INTRODUCTION AND MOTIVATION

Generalization of Vélu's formulae

Given an elliptic curve $E$ and a finite subgroup $G$, Velu's formulae concern to a separable isogeny $\mathcal{I}_G\colon E\to E'$ with kernel $G$. In particular, for a point $P\in E$ these formulae express the first elementary symmetric polynomial on the abscissas of the points in the set $P+G$ as the difference between the abscissa of $\mathcal{I}_G(P)$ and the first elementary symmetric polynomial on the abscissas of the nontrivial points of the kernel $G$. On the other hand, they express Weierstrass coefficients of $E'$ as polynomials in the coefficients of $E$ and two additional parameters: $w_0=t$ and $w_1=w$. We generalize this by defining parameters $w_n$ for all $n\ge 0$ and giving analogous formulae for all the elementary symmetric polynomials and the power sums on the abscissas of the points in $P+G$. Simultaneously, we obtain an efficient way of performing computations concerning the isogeny when $G$ is a rational group.

Partial known plaintext attack on Koyama scheme

This paper analyzes the conjecture made by Koyama regarding partial known plaintext attack on Koyama scheme. According to him, such attack is not possible even if one ordinate of the plaintext pair...

Investigation of NO Formation Characteristics in Multi Staged Air Combustor

In this study, a numerical simulation was developed which was capable of predicting the characteristics of NO formation in pilot scale combustor adopting the air-staged burner flame. The numerical calculation was constructed by means of establishing the mathematical models fur turbulence, turbulent combustion, radiation and turbulent nitric oxide chemistry. Turbulence was solved with standard k- model and the turbulent combustion model was incorporated using a two step reaction scheme together with an eddy dissipation model. The radiative transfer equation was calculated by means of the discrete ordinates method with the weighted sum of gray gases model for COand HO. In the NO chemistry model, the chemical reaction rates for thermal and prompt NO were statistically averaged using the probability density function. The results were validated by comparison with measurements. For the experiment, a 0.2 MW pilot multi-air staged burner has been designed and fabricated. Only when the radiation was taken into account, the predicted gas temperature was in good agreement with the experimental one, which meant that the inclusion of radiation was indispensable for modeling multi-air staged gas flame. This was also true of the prediction of the NO formation, since it heavily depended on temperature. Subsequently, it was found that the multi-air staged combustion technique might be used as a practical tool in reducing the NO formation by controlling the peak flame temperature.

Numerical Study on Pulverized Coal Combustion Applying Two-Phase WSGGM

A numerical study on swirling pulverized coal combustion in an axisymmetric enclosure is carried out by applying the 2-phase weighted sum of gray gases model (WSGGM) approach with the discrete ordinate method (DOM) to model the radiative heat transfer equation. In the radiative transfer equation, the same polynomial equation and coefficients for weighting factors as those for gas are adopted for the coal/char particles as a function of partial pressure and particle temperature. The Eulerian balance equations for mass, momentum, energy, and species mass fractions are adopted with the standard and RNG k- turbulence model, whereas the Lagrangian approach is used for the particulate phase. The eddy-dissipation model is employed for the reaction rate for gaseous mixture, and the single-step and two-step first-order reaction model for the devolatilization process for coal. Special attention is given to establish the thermal boundary conditions on radiative transfer equation By comparing the numerical results with experimental ones, the radiation model used here is confirmed and found to provide an alternative for simulating the radiative transfer.

A numerical study on the combined natural convection and radiation in a partially open complex enclosure with a heater and partitions

A numerical simulation on the combined natural convection and radiation is carried out in a partially open rectangular enclosure with a heater by using the finite volume and the S-8 discrete ordinate methods. The fluid inside the enclosure is considered as an absorbing, emitting and anisotropic scattering media. The heater causes a natural circulation of the fluid (10 ) which results in significant in-flow of the ambient cold fluid through the partially open wall. Comparing the results of pure convection with those of the combined convection- radiation, the combined heat transfer results with small Planck numbers (P