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Experimental works on bubble column hydrodynamic are normally carried out on a laboratory scale less than 0.3 m with holes number less than 10. In this paper, we discuss several approaches to bubble column scale-up, relying on variables of parameters. Two spargers with different hole diameters (0.5 mm and 1.25 mm) and superficial gas velocities (0.0125 m/s and 0.0501 m/s) are used to determine the distribution of gas holdup and liquid flow pattern. An Insignificant level of bed heights is investigated for the efficiency of hydrodynamic performance. Computational Fluid Dynamic (CFD) is used as the realistic representation of the actual reactor. The flow of the gas-liquid interface is implemented using the VOF model using the finite volume method by tracking the volume fraction of each of the fluids throughout the domain. It is observed that the initial bed heights, superficial gas velocity, and hole diameter of the sparger influence the overall gas holdup. Although the difference in sparger hole diameter affects overall gas holdup, the results are weak relative to other operating conditions. The simulation work is then compared with experimental data to improve the accuracy in analyzing the hydrodynamics of multiphase system, as well as validated the multidimensional models.

Radiotracer technique is well established assisting tools for troubleshooting and process optimization in process industries. Industrial radiotracer has proved to be a very useful tool to examine and improve the design of pilot-scale systems. However, to date, no detailed large-scale studies have been performed to investigate the capability of nanoparticle radiotracers in any pilot plant or laboratory scale vessels. Thus, the performances of the nanoparticle radiotracer for industrial application purposes are being questioned. This study has demonstrated the entire design development process of a bubble column reactor test rig for investigating hydrodynamics behaviour using industrial radiotracer techniques with aid of complete system. The influence of superficial gas velocity and sparger design on gas hold up in bubble column has been successfully studied. Therefore, the hydrodynamic parameters of the bubble column reactor are validated using the conventional method with the aid of high-speed camera technology. The results indicate that the higher sparger opening area contributed to higher gas holdup up to 50% from initial water level and increased the value superficial gas velocity which resulting increasing Reynolds number value. From the qualitative observation analysis and Reynolds number information, the flow regimes for bubble column reactor are determined from homogeneous to heterogeneous flow successfully. The solid nano-sized particle radiotracer 198Au@SiO2 has been synthezised and characterized for tracing liquid phase effectively. The performance of newly synthesized industrial radiotracers was successfully validated by investigating aqueous phase system in bubble column reactor at different air flow rates and sparger design using radiotracer flow measurement method and residence time distribution studies with accuracy more than 98%. The results of flow measurement show that the experimental volumetric flow rate is in good agreement with conventional flo

Bubble column reactor belongs to the general class of multiphase reactors in which gas come in contact with liquid. This reactor purposely used to mix the two phases or substances where the gas is dispersed into the column from the bottom and rises within the liquid and escapses from the upper liquid surface. Throughout the design and development phase, the reactor design specifications were identified to meet the experimental requirements for hydrodynamics study in a bubble column using the high-speed camera, industrial radiotracer, and radioactive particle tracking techniques. This bubble column reactor design comes with six different type of sparger design for various mixing pattern optimization. The design methodology structured as design development process, conceptual design selection process, detailed design specifications, product fabrication, and final product testing. This versatile reactor is developed to overcome the problems faced in understanding hydrodynamics behavior of using different types of sparger design, leading to design optimization for better mixing and blending efficiency in multiphase flow investigations. This study has demonstrated that the newly quadrilateral bubble column reactor is ready to be used for the various types of laboratory assessment including industrial radioactive experiments.

In this work, we have quantified the influence of superficial gas velocity and sparger design on bubble size, gas hold-up, and bubble rise velocity in quadrilateral bubble column test rig (0.2 x 0.2 m in cross-section and 2 m in height). Six sparger designs were used to generate homogeneous to heterogeneous flow regime for the investigation of the effect of superficial gas velocity and sparger design on gas holdup and bubble size distribution in a bubble column. This study has proved that the air distributor optimization can be recognized using high-speed camera technique. The size of bubbles inside the column is also affected by the size of orifice diameter and number of holes of the sparger. This study concludes that Sparger C and Sparger D design with orifice size 0.5 mm may use optimum gas flow rate to generate homogeneous bubbly flow with higher gas hold-up for better mixing process in this bubble column reactor. At heterogeneous flow regime, it was observed that the sparger orifice diameter shown little impact on the column behavior. The experimental results also can subsequently be applied to the development and validation of the proper mathematical model.

Measurement of discharge rates of fluids and solids is an essential requirement in industrial systems. Industrial processes worldwide are progressively recognizing the value of industrial radiotracer application in studying the operation of the on-line plant. Radiotracer techniques are widely used for measurement of fluids/solids in situations where conventional techniques cannot be applied. This present report describes the flow rate measurement using radioisotope technique using unsealed radioactive source to calibrate the installed flowmeters and to measure the flow rate in systems, which does not influence the on-line process. An investigation was performed by the injection of a radiotracer inside the multiphase flow rig system to provide fluid flow rate information. In this study, the multiphase rig was filled up with mixed oil-water, and the Coriolis flowmeter was installed in the system for efficiency validation. Cs-137/Ba-137m radioisotope generators were used to prepare the radiotracer and Ba-137m radioisotopes having activity about 0.2 mCi. The peak to peak method was applied for the radiotracer techniques. The average volumetric flow rate of multiphase flow rig was measured to be 6.43 m3/h. This study has proved that Coriolis flowmeter is not functioning in good condition due to different flow rate value from the experimental works and suggested to be recalibrated or replace.

Radioisotope techniques are constantly and extensively used all over the world as a method to identify process systems malfunctions in various industries without requiring the shut down of the processing plant thus leading to high economical benefits to the plant owner. Different aspects of industrial radiotracer technology for troubleshooting, process control and optimization are evaluated through an exhaustive literature survey. The review covers the advantages of radiotracers, most commonly used radiotracers in industry for specific studies, applications of radiotracer techniques in various chemical industries, the design of radiotracer technology experiments, radiation detection and data acquisition in radiotracer technology as well as radiological safety aspects. Two industrial radiotracer techniques of residence time distribution (RTD) measurements and radioactive particle tracking (RPT) are discussed. The design of radiotracer technology experiments are also divided into two categories-radioactive particle tracking applications and residence time distribution applications.

Radioactive particle tracking (RPT) has emerged as a promising and versatile technique that can provide rich information about a variety of multiphase flow systems. However, RPT is not an off-the-shelf technique, and thus, users must customize RPT for their applications. This paper presents a simple procedure for preparing radioactive tracer particles created via irradiation with neutrons from the TRIGA Mark II research reactor. The present study focuses on the performance evaluation of encapsulated gold and scandium particles for applications as individual radioactive tracer particles using qualitative and quantitative neutron activation analysis (NAA) and an X-ray microcomputed tomography (X-ray Micro-CT) scanner installed at the Malaysian Nuclear Agency.

The present invention relates to a radioactive tracer characterized by a silica-coated gold nanoparticle comprising 0.1 to 1 wt% gold, having a diameter in a range of 70 to 200 nanometers and radioactivity in a range of 55.5 to 129.5 MBq. The present invention also provides a method for producing a radioactive tracer comprising a silica-coated gold nanoparticle, characterized by the steps of heating the colloidal gold nanoparticle solution; mixing the colloidal nanoparticle solution with an alcohol to form a mixture; adding an ammonia solution, followed by a silica compound into the mixture to form the silica-coated gold nanoparticle; washing and centrifuging the silica-coated gold nanoparticle, thereby separating the silica-coated gold nanoparticle from unwanted solution; calcining the silica-coated gold nanoparticle for producing silica-coated gold nanoparticle powder; subjecting the silica-coated gold nanoparticle powder to neutron irradiation.

Background: To meet the current diversified health needs in workplaces, especially in nonindustrial workplaces in developing countries, an indoor air quality (IAQ) component of a participatory occupational safety and health survey should be included. Objectives: The purpose of this study was to evaluate and suggest a multidisciplinary, integrated IAQ checklist for evaluating the health risk of building occupants. This IAQ checklist proposed to support employers, workers, and assessors in understanding a wide range of important elements in the indoor air environment to promote awareness in nonindustrial workplaces. Methods: The general structure of and specific items in the IAQ checklist were discussed in a focus group meeting with IAQ assessors based upon the result of a literature review, previous industrial code of practice, and previous interviews with company employers and workers. Results: For practicality and validity, several sessions were held to elicit the opinions of company members, and, as a result, modifications were made. The newly developed IAQ checklist was finally formulated, consisting of seven core areas, nine technical areas, and 71 essential items. Each item was linked to a suitable section in the Industry Code of Practice on Indoor Air Quality published by the Department of Occupational Safety and Health. Conclusion: Combined usage of an IAQ checklist with the information from the Industry Code of Practice on Indoor Air Quality would provide easily comprehensible information and practical support. Intervention and evaluation studies using this newly developed IAQ checklist will clarify the effectiveness of a new approach in evaluating the risk of indoor air pollutants in the workplace.

Thin films of Copper Tin Selenide (Cu2SnSe3), were successfully deposited on well-cleaned glass substrates by thermal evaporation technique. The as-deposited films were annealed in flowing purified nitrogen, N2, for 2 h in the temperature range from 100 to 500°C. The annealing temperature effect on thin films crystallization and light effect on electrical conductivity had been investigated. X-ray diffractometer (XRD) and Atomic force microscope (AFM) were used for the investigation of structural behavior of Cu2SnSe3 thin films. These studies revealed that the films were structured in mixed phases between cubic space group F-43m (no. 216) and orthorhombic space group P n m a (no. 62) belonging to Cu2SnSe3 and SnSe, respectively. The results determined from Scherrer calculation method showed that increasing in annealing temperature resulted in direct increase of crystallite size and average grain size. The annealing effect on surface morphologies and the light effect on I-V characteristics of Cu2SnSe3 thin films were reported and it was found that the current increased with increasing annealing temperature and light intensity. Photosensitivity of Cu2SnSe3 thin films decreased with increasing annealing temperature but increased with increasing light intensity.

Semiconductor thin films copper tin selenide, Cu2SnSe3, a potential compound for solar cell applications or semiconductor radiation detector were prepared by thermal evaporation method onto well-cleaned glass substrates. The as-deposited films were annealed in flowing purified nitrogen, N2, for 2 h in the temperature range from 100 °C to 500 °C. The structure of as-deposited and annealed films has been studied by X-ray diffraction technique. The semi-quantitative analysis indicated from the Reitveld refinement show that the samples composed of Cu2SnSe3 and SnSe. These studies revealed that the films were structured in mixed phase between cubic space group F-43m (no. 216) and orthorhombic space group P n m a (no. 62). The crystallite size and lattice strain were determined from Scherrer calculation method. The results show that increasing in annealing temperature resulted in direct increase in crystallite size and decrease in lattice strain.