Preferred Language
Articles
/
joe-2965
INVESTIGATION OF TWISTED TAPE TURBULATOR FOR FIRE TUBE BOILER Part I. Heat Transfer
...Show More Authors

The present work presents a new experimental study of the enhancement of turbulent
convection heat transfer inside tubes for combined thermal and hydrodynamic entry length of one
popular “turbulator” (twisted tape with width slightly less than internal tube diameter) inserted for
fire tube boilers. Cylindrical combustion chamber was used to burn (1.6 to 7kg/h) fuel oil #2 to
deliver hot gases with ranges of Reynolds number (10500 to 21700), and (11400 to 24150) for both
empty and inserted tube respectively.A uniform wall temperature technique was used by keeping
approximately constant water temperature difference (25ºC) between inlet and exit cooling water in
parallel flow shell and tube heat exchanger. The test tube consisted of smooth carbon steel tube of
(2400mm) long and (52mm) internal diameter. This test tube instrumented to derive local heat
transfer coefficient and local flue gasses static pressure.The experimental results show that for the
same fuel consumption, twisted tape insert with (H/D = 11.15) enhanced the mean Nusselt number
in (75.2%), (68.8%), (49.8%), (40.3%), and (16.7%) for fuel consumption (7kg/h), (6.16kg/h),
(4.5kg/h), (3.24kg/h), and (1.6kg/h) respectively.A set of empirical correlations that permit the
evaluation of the mean Nusselt number (for developing and fully developed region), and average
Nusselt number (for developed region) for empty and inserted tube are generated for engineering
applications.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Mon Sep 23 2019
Journal Name
Baghdad Science Journal
Hazard Rate Estimation Using Varying Kernel Function for Censored Data Type I
...Show More Authors

     In this research, several estimators concerning the estimation are introduced. These estimators are closely related to the hazard function by using one of the nonparametric methods namely the kernel function for censored data type with varying bandwidth and kernel boundary. Two types of bandwidth are used:  local bandwidth and global bandwidth. Moreover, four types of boundary kernel are used namely: Rectangle, Epanechnikov, Biquadratic and Triquadratic and the proposed function was employed with all kernel functions. Two different simulation techniques are also used for two experiments to compare these estimators. In most of the cases, the results have proved that the local bandwidth is the best for all the

... Show More
View Publication Preview PDF
Publication Date
Sat Jan 01 2022
Journal Name
Journal Of Engineering
Serviceability of Post-fire RC Rafters with Openings of Different Sizes and Shapes
...Show More Authors

This study deals with the serviceability of reinforced concrete solid and perforated rafters with openings of different shapes and sizes based on an experimental study that includes 12 post-fire non-prismatic reinforced concrete beams (solid and perforated). Three groups were formed based on heating temperature (room temperature, 400 °C, and 700 °C), each group consisting of four rafters (solid, rafters with 6 and 8 trapezoidal openings, and rafter with eight circular openings) under static loading. A developed unified calculation technique for deflection and crack widths under static loading at the service stage has been provided, which comprises non-prismatic beams with or without opening exposed to flexure concentra

... Show More
View Publication Preview PDF
Crossref (7)
Crossref
Publication Date
Thu Jan 08 2015
Journal Name
Chemical And Process Engineering Research
Uni and Simplex Optimization for the Spectrophotometric Determination of Erythromycin ethylsuccinate Drug via Charge-Transfer Complex Formation
...Show More Authors

Charge transfer complex formation method has been applied for the spectrophotometric determination of erythromycin ethylsuccinate, in bulk sample and dosage form. The method was accurate, simple, rapid, inexpensive and sensitive depending on the formed charge- transfer complex between cited drug and, 2,3- Dichloro-5,6-dicyano-p- benzoquinone (DDQ) as a chromogenic reagent. The formed complex shows absorbance maxima at 587 nm against reagent blank. The calibration graph is linear in the ranges of (10 - 110) μg.mL-1 with detection limit of 0.351μg.mL-1. The results show the absence of interferences from the excipients on the determination of the drug. Therefore the proposed method has been successfully applied for the determination of eryth

... Show More
Preview PDF
Publication Date
Mon Jun 01 2015
Journal Name
Journal Of Engineering
Using Nanoparticles for Enhance Thermal Conductivity of Latent Heat Thermal Energy Storage
...Show More Authors

Phase change materials (PCMs) such as paraffin wax can be used to store or release large amount of energy at certain temperature at which their solid-liquid phase changes occurs. Paraffin wax that used in latent heat thermal energy storage (LHTES) has low thermal conductivity. In this study, the thermal conductivity of paraffin wax has been enhanced by adding different mass concentration (1wt.%, 3wt.%, 5wt.%) of (TiO2) nano-particles with about (10nm) diameter. It is found that the phase change temperature varies with adding (TiO2) nanoparticles in to the paraffin wax. The thermal conductivity of the composites is found to decrease with increasing temperature. The increase in thermal conductivity ha

... Show More
View Publication Preview PDF
Publication Date
Sun Sep 01 2019
Journal Name
Journal Of Physics: Conference Series
Recovery of temporal coefficient for heat equation from non-local overdetermination conditions
...Show More Authors
Abstract<p>Recovery of time-dependent thermal conductivity has been numerically investigated. The problem of identification in one-dimensional heat equation from Cauchy boundary data and mass/energy specification has been considered. The inverse problem recasted as a nonlinear optimization problem. The regularized least-squares functional is minimised through lsqnonlin routine from MATLAB to retrieve the unknown coefficient. We investigate the stability and accuracy for numerical solution for two examples with various noise level and regularization parameter.</p>
View Publication
Scopus (1)
Scopus Crossref
Publication Date
Tue Jun 30 2020
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Investigation of Ozone Microbubbles for the Degradation of Methylene Orange Contaminated Wastewater
...Show More Authors

   In the present study, semi – batch experiments were conducted to investigate the efficiency of ozone microbubbles (OMBs) in the treatment of aqueous dye solutions methylene orange under different reaction conditions such as  effect of initial solution pH , ozone generation rate and initial MO-concentration. The results showed that the removal of MO by OMBs were very high at the acidic and alkaline media and upon increasing the generation rate of ozone from 0.498 to 0.83 mg/s, the removal efficiency dramatically increased from 75to 100% within 15 min. The rate of oxidation reaction followed a pseudo first- order kinetic model. The results demonstrated that OMBs is efficient in terms of the decline of methylene orange c

... Show More
View Publication Preview PDF
Crossref (11)
Crossref
Publication Date
Sat Apr 01 2023
Journal Name
International Journal Of Modern Physics E
Hamiltonian sensitivity in calculating the electromagnetic moments and electroexcitation form factor for the <i>sd</i> nuclei using shell model with Skyrme–Hartree–Fock
...Show More Authors

In this work, the nuclear electromagnetic moments for the ground and low-lying excited states for sd shell nuclei have been calculated, resulting in a revised database with 56 magnetic dipole moments and 41 electric quadrupole moments. The shell model calculations are performed for each sd isotope chain, considering the sensitivity of changing the sd two-body effective interactions USDA, USDE, CWH and HBMUSD in the calculation of the one-body transition density matrix elements. The calculations incorporate the single-particle wave functions of the Skyrme interaction to generate a one-body potential in Hartree–Fock theory to calculate the single-particle matrix elements. For most sd shell nuclei, the experimental data are well rep

... Show More
View Publication
Scopus (2)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Thu Jun 01 2023
Journal Name
Baghdad Science Journal
Estimation of Parameters for the Gumbel Type-I Distribution under Type-II Censoring Scheme
...Show More Authors

This paper aims to decide the best parameter estimation methods for the parameters of the Gumbel type-I distribution under the type-II censorship scheme. For this purpose, classical and Bayesian parameter estimation procedures are considered. The maximum likelihood estimators are used for the classical parameter estimation procedure. The asymptotic distributions of these estimators are also derived. It is not possible to obtain explicit solutions of Bayesian estimators. Therefore, Markov Chain Monte Carlo, and Lindley techniques are taken into account to estimate the unknown parameters. In Bayesian analysis, it is very important to determine an appropriate combination of a prior distribution and a loss function. Therefore, two different

... Show More
View Publication Preview PDF
Scopus Crossref
Publication Date
Fri Jun 15 2018
Journal Name
Journal Of Baghdad College Of Dentistry
Determination the concentration of insulin-like growth factor-I (IGF-I) in saliva of acromegalic patients, and comparison it with the levels of serum IGF-I.
...Show More Authors

Acromegaly is ametabolic disorder characterized by an acquired progressive somatic disfigurement, mainly involving the face, extremities and many other organs, that are associated with systemic manifestations, caused by excessive secretion of growth hormone and a resultant persistent elevation of insulin-like growth factor-I concentrations. In more than 90% of cases originates from a monoclonal benign pituitary adenoma. Aim of this study to assess the level of insulin-like growth factor-I (IGF-I) in saliva of acromegalic patients, and to compare it with the basal levels of serum IGF-I. Sixty specimens of serum and saliva collected from two groups of subjects (forty acromegalic patients and twenty healthy persons). The specimens were

... Show More
View Publication
Crossref (1)
Crossref
Publication Date
Mon Aug 14 2023
Journal Name
Mammalia
First record of the Small Indian Mongoose <i>Urva auropunctatus</i> (Hodgson 1836) from Syria
...Show More Authors
Abstract<p>The Small Indian Mongoose <italic>Urva auropunctata</italic> (Hodgson 1836) is a small carnivore native to Iraq and South Asia; however, it has been widely introduced worldwide. The species has never been reported in Syria; however, it was suspected to occur in the extreme eastern parts of the country, but no confirmed records were made. In 2021–2022, several sightings were notified during <italic>in situ</italic> surveys in Deir ez-Zor Province in eastern Syria which confirm the first occurrence of the Small Indian Mongoose in the country.</p>
View Publication
Scopus (1)
Scopus Clarivate Crossref