Articles

A Review of CO2 Adsorption From Ambient Air (Direct Air Capture)
Hind Jihad Kadhim Shabbani (Author)
March 2020 ,Pages 1.0-6.0

Abstract: Direct Air Capture (DAC) has risen in the past decade as a promising choice to remove CO2 directly from ambient air. Although there are many technologies like pre-combustion, post-combustion and oxy-combustion to mitigate the emissions of CO2, there is still a need for a better or a complementary technology in controlling these emissions. Even though, there are many options for adsorbents that can be used, metal-organic frameworks (MOFs), which are hybrid materials with a crystalline structure, tunable pores, and high surface area, have risen as a promising candidate.  Functionalizing MOFs with amine groups will greatly enhance their capacity towards CO2, like mmen-M2 (dobpdc) (M=Mg, Fe, Mn, Zn, Co). These adsorbents show S-shaped adsorption isotherms and have a very high affinity to CO2 under atmospheric conditions, due to the cooperative insertion of CO2 into mmen-M2 (dobpdc) that leads to their unique adsorption isotherms. The energy required to regenerate these materials using small heat variations makes a better choice than aqueous amines. This mechanism has been studied by using X-Ray Diffraction (XRD) and spectroscopy experiments. Furthermore, a thermodynamic study has been reviewed to understand the mechanism through which CO2 is inserted into the diamine bond. These materials are a promising choice for the removal of CO2 directly from the atmosphere and require more future research.

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Effect of Polymer’s Type and Content on Tensile Strength of Polymers Modified Asphalt Mixes
Ghufraan Mohammed Aboud, Nabil Habib Jassem, Teba Tariq Khaled, Azaldeen Ali Abdulhussein, Vikas Kumar (Author)
March 2020 ,Pages 7.0-12.0

Abstract: There has been a considerable rise in road traffic in the past twenty years due to the fast-pace development of the country. In addition, the inadequate and less frequent maintenance exacerbated the deterioration of road structure. This increase in traffic volume combined with the harsh climatic environment of Iraq causes early signs of distress such as low-temperature cracking, rutting, and fatigue cracking. Polymers obtained from the local sources or recycled additive from other sources have been used in pavements to improve their performance as well as to make them more sustainable. This paper presents a laboratory evaluations that were used to determine mechanical characteristics and performance of asphalt mixtures with different types of additives such as (Polyvinyl Chloride (PVC) and Natural Rubber (NR)) and various content. The modified asphalt mixtures were prepared with asphalt binder previously modified by using four percentages of polymer (2, 4, 6, and 8%) from the weight of asphalt binder. Many tests were conducted to evaluate mixtures performance such as (the volumetric properties, mechanical characteristics, indirect tensile strength (ITS) test, and double punching shear (DPS)). The results indicated that the PVC polymer and natural rubber improved the performance of the mixtures compared to the control mixture.

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Comparative study for adsorption of acidic and basic dyes on activated carbon prepared from date stone by different activation agent
Azhaar Radhi Jabbar (Author)
March 2020 ,Pages 13.0-21.0

Abstract: This research includes a lab scale work to investigate the feasibility of treating waste water which polluted with dyes exhausted from textile factory by using adsorption process. Three type of activated carbon were prepared using locally available waste material (date stone). Chemical activation method  with (zinc chloride, potassium hydroxide, or phosphoric acid) was used  as activators  to  prepared carbon. Firstly, the materials were carbonized at 275 oC for 90 min and then the carbonized materials were treated with (4 molar) solution of acid, base or salt for 24 hour. Finally, these materials were activated at 600 oC for two hours in the presence of nitrogen gas flow. The resulted activated carbons were checked by its (BET) surface area analysis and surface morphology by SEM. The surface area values were (815, 950,600) m2/g for carbon produced from the activation of date  stone by phosphoric acid, potassium hydroxide or zinc chloride respectively. SEM characterizations show that activated carbons that prepared from potassium hydroxide have higher surface area and good adsorption characteristics than that prepared from activation with phosphoric acid or zinc chloride. The  adsorption process was studied using two types of dyes. The first one is acidic (methyl orange) and the other is basic (bismark brown). The adsorption isotherms and kinetics where investigated for both dyes at temperatures (30,40,50,60)oC for concentration  range  equal to (6-16)mg/l.  The  adsorption data of equilibrium were presented by using two common adsorption isotherm equations. The data was fitted fairly well with Langmuir isotherm for both dyes on all types of prepared activated carbons. The kinetic of adsorption was study by using two kinetic equations, pseudo first order and pseudo second order. The result showed the rapid increase in the rate of adsorption at the initial until equilibrium achieved. Pseudo second order model were represent the data very well with confidence level 0.99.

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Synthesis and Characterization of New Dental Composite for Dentistry Based on Unsaturated Monomers and Nano-fillers by Photopolymerization
Mahdi Saleh Mahdi, Mohammed Ali Mutar (Author)
March 2020 ,Pages 22.0-30.0

Abstract: In this study, dental nano-composite specimens were prepared by dispersion of various amounts of nano-sized fillers (HA, ZrO2, and SiO2) in a monomer system containing 60% Bis-GMA and 40% TEGDMA. 2,2 propyl bis-phenyl glycidyldimethacrylate (Bis-GMA) with unsaturated monomers were prepared. Camphor Quinone (CQ) of 1 wt %, 2-DiMethyl Amino Ethyl Methacrylate (DMAEMA) of 1 wt % have been applied in photo-initiation system for the purpose of initiating matrix resins’ co-polymerization. Wear resistance, flexural strength, hardness and compressive strength were measured. The results indicated an increase in the mechanical properties in the samples containing nano-size filler particles. It is interesting to note that, this improvement was observed at much lower nano-size filler content. Physicochemical properties, such as Solubility (SL), Water Sorption (WS) as well as the Volumetric Shrinkage (VS) have been examined. FT-IR as well as SEM have been utilized for implementing the characterization. SEM has been applied for showing particle size distribution as well as the particle agglomeration that is related to the treated nano-fillers in nano-composites. FT-IT is initially applied for identifying qualitative compositions regarding the nano-composites’ compositions. The Thermal stability of all dental nano-ocomposites was also studied using TGA and DSC techniques.

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Structural Behavior of Novel ECC Short Columns Subjected to Eccentric Loading
Safaa mashshay, Adnan Al-Sibahya (Author)
March 2020 ,Pages 31.0-36.0

Abstract: This study was undertaken in order to investigate the structural behaviour of novel Engineering Cementitious Composites (ECC) columns subjected to eccentric loading. These columns were experimentally formulated using a hybridization of steel and polypropylene fibres. Two ratios were adopted for the steel fibres of 0.5% and 1%, whilst the polypropylene fibre was kept to be constant at a ratio of 0.5% for all of the ECC columns. The eccentric loads were applied at two eccentricities: small (h/6) and large (5h/12). A comparison was also made with the behaviour of self-compacting concrete and traditional ECC columns containing either steel or polypropylene fibres. The vertical and lateral deformations as well as the maximum load at failure were noted. The results obtained showed that the hybrid ECC columns exhibited higher load carrying capacities when compared with those of both self-compacting concrete and traditional ECC columns. The percentage increase was 30%.  The hybrid ECC column samples containing 1% steel fibre did not show a signification difference in the load-deformation behaviour when it compared with that containing 0.5% steel fibre. The values of eccentricity governed the global behaviour of the tested columns. The predicated load carrying capacity of the ECC columns needs a magnification factor in case of concentric test, and to take into account the existence of fibres ratio when calculating the area of steel reinforcement for eccentric loading.

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The Numerical and Experimental Analysis to Study the Effect of Double Triangle Core on the Dynamic Response of Sandwich Structure
Safaa mohammed Hoala, Hatem Hadi Obeid, Essam Zuheir Fadhel (Author)
March 2020 ,Pages 37.0-45.0

Abstract: Sandwich structure plates are most widely used in the automotive, aerospace and naval structures. As it gives material with low density and relatively high normal compression and shear properties. In this paper, Finite element method was used with ANSYS APDL (16) to analyze the effect of duplicate core in sandwich steel structure on the dynamic response under the action of impact loading. Also, conducted impact tests with hammer and NI devises to achieve the simulation results. The chief purpose of this work is to get a high reduction in deformation between upper and lower skins. Isolate deflections of sandwich plates are compared between single and double cores of structures. The construction of the sandwich composite model consisted of two sheets layers with single triangle corrugated core and three sheets layer with double triangle corrugated core. All of configurations for both core and skin are made from the same material (steel alloy 304) and have (500mm × 500mm) length and width . The properties of materials are isotropic and have an elastic modulus (198 Gpa), density (7835 kg/m3) and Poisson ratio is (0.3). The results observed that the reduction of deflection and strain are increased in double core. The comparison between experimental and numerical transient results gives good agreement with error does not exceed (13%).

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Developing Sustainable Concrete Compaction using a Proposed Multi-vibration Technique
Sajid Kamil Zemam (Author)
March 2020 ,Pages 46.0-54.0

Abstract: This study seeks to develop a sustainable construction technique based on the introduction of a specific method for improving concrete compressive strength through a proposed multi-vibration compaction method. An experimental program is performed to evaluate the effect of the proposed compaction technique on fresh silica fume concrete undergoing the initial setting. Multi-vibration intends to minimize concrete production cost because it upgrades the compressive strength of the same materials with better utilization of the vibration energy required for compaction. The collected experimental data presented assign relationships among vibration duration, vibration cycles or phases, and compressive strength upgrading of single vibrated, revibrated, and multi-vibrated specimens for analysis and discussion. This study shows that multi-vibration phases, rather than single vibration or revibration techniques, are powerful techniques for improving concrete compressive strength. The results indicated that the existence of an optimum multi-vibration mode was dominated by phase number and vibration duration and confirm the reliability vibration overall time duration recommended by ACI 309 which relates to a single vibration time limit to be considered in the case of multi vibration technique. Multi-vibration Mode 8 (subjected to three vibration phases 10, 20, and 30 sec ) has the best effect for the considered mixtures among the specific vibration modes. The maximum improvement ratio is 1.25, which is associated with the plastic mixture.   

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Implementation of Intelligent Industrial Controller Based On Fuzzy Logic and PLC
Methaq Abdulameer Ali, Abbas Miry, Tariq Salman (Author)
March 2020 ,Pages 55.0-60.0

Abstract: The Internet of Things (IoT) makes designing a smart management system is real and easy. The concept of smart management system guarantees a person to monitor, control and manage the system without any waste. Water is a key resource and its management is a major issue. The proposed method is IOT with the fuzzy controller based system for managing tank water level in Rumaila power plant from gas (in southern Iraq).  The existing system, designed with two electric motor pumps, supplies a storage tank with untreated water from the river for later use in (reverse Osmosis) R.O. This system is manual without efficient monitoring and control system. This paper includes two implemented control systems; the classic PID and Fuzzy logic with a comparison between them. Fuzzy control is simulated first using Matlab and then developed by Sugeno-based Fuzzy algorithm within the PLC (Programmable Logic Console) environment. The connection of PLC with OPC (Object Process Control) server used by the Modbus protocol while the sensors connected directly to Kayenne platform.  Using the OPC and MQTT, the IoT system is built up to publish and subscribe the data from PLC and cloud. Node MCU- ESP8266 is used by wireless communication to link the sensors with router.

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An Experimental Investigation of Overall Mass Transfer coefficient (KGa) of CO2 absorption using Monoethanolamine (MEA) and Diethanolamine (DEA) in a Bubble Column Reactor (BCR)
Elaf Thamer, Salih Abduljabbar Rushdi (Author)
March 2020 ,Pages 68.0-73.0

Abstract: In this work, an absorption technology   was used actually to investigation the  mass transfer coefficient of carbon dioxide from a gaseous mixture (air, carbon dioxide) in  blended solution Monoethanolamine (MEA) and Diethanolamine (DEA)  in a bubble column reactor (BCR) . The bubble column reactor(BCR) was made of Plexiglas with 1.5 m high and 0.1 m inside diameter. The overall mass transfer coefficient (  was evaluated at different operating conditions , gas flow rate, air Flow rate ,liquid flow rate .Where the gas flow rates were 10, 15 and 20 L /min ,  air flow rate 100,150 and 200 L/h ,and liquid flow rate 5 ,10,15 L /min . This experiment  by   using  continuous   process with helping centrifugal  pump  . High-performance gas chromatographic (GC) was performed to evaluate  loading during absorption experiment . The  experimental results have shown that the   loading in range of  0.581-1.367 (mol  /mole amine),and the maximum value of overall mass transfer coefficient ( KG) was 0.04 S-1 .

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