bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparative Study of Performance of Al-Khairat Gas Turbine Power Plant for Different Types of Fuel
Authors: Kadhim Hayder Jawad , Kadhim Thualfaqir J. , Alhwayzee Mohammed H
Published: January 2020

In this work, the effect of various types of fuels on the performance and efficiency of Al-Khairat gas turbine power plant in Kerbala City, Iraq has been investigated. The plant contains 10 General Electric Frame 9E gas turbine units, each of around 125 MW. Three fuels were used in this study; crude oil, natural gas, and biomass gasification producer (synthesis) gas. Currently, liquid crude oil is used as fuel for this plant. For comparison purposes, this power plant was simulated utilizing Aspen-Hysys software. Hysys simulation modelled in accordance with experimental power plant conditions and data was applied and showed high validity. Due to this validity, the plant’s efficiency and performance were calculated. Similarly, plant efficiency and performance for the other two fuels were also calculated. Furthermore, many important parameters that affect plant efficiency and performance for these three fuels (ambient temperature, pressure ratio, CO2 emission gases, heat rate and fuel consumption) were also investigated. Compared to the other two fuels, results show that the use of natural gas is the optimal choice for the plant, due to its increase of station efficiency and productivity, by approximately 3.12% and 10% respectively. At the same time, it reduced fuel consumption by 6% and produced less emission greenhouse gas.
Experimental and Numerical Investigation of Temperature Distribution in the Cutting Zone with Different Coated Tools in Orthogonal Turning Operations
Authors: Sahib Basim S. , Nassrullah Karrar S.
Published: January 2020

In orthogonal turning operations, the mechanical energy is converted into heat. The generated heat influences tool life and wear, and the accuracy and quality of workpieces. In the current work, the temperature distribution at cutting zone was studied experimentally and numerically. The K-type thermocouple was utilized to measure the cutting zone temperature during turning process for steel AISI 1010. DEFORM-2D has been utilized to simulate the turning operation, which was carried out using many coated and uncoated carbide tools. The experimental tests were implemented at constant depth of cut with different feed rates and cutting speeds. The results of numerical and experimental tests are illustrated. The influences of coated and uncoated tools, feed rate and cutting speed in temperature distribution at cutting zone are discussed, whereby the TiN/Al2O3/TiCN coated tool has the lowest temperature distribution at cutting zone compared to the other coated and uncoated tools, while the uncoated tool has the highest temperature distribution compared to coated cutting tools. Also, the increasing of cutting speed and feed rate led to an increase of temperature at the cutting zone.
Advance Acceptance Status Model for E-learning Based on University Academics and Students
Authors: Mousa Ayad Hameed , Mousa Seham Hameed , Mousa Sundus Hameed , Obaid Hazim Allawi
Published: January 2020

E-learning provides students with the possibility of accessing, repeating, and using learning materials wherever and whenever they want. The philosophy of e-learning is not to replace the conventional learning process; it instead provides a new method and approach that offers opportunities for much faster delivery of knowledge. Teachers and students are the most significant actors in the process of educational transformation, and technology acceptance is measured by positive reactions from users based on their utilisation of technology to support those assignments designed for such purposes. In higher education institutions in Iraq, the use of e-learning has become compulsory and there is thus a critical need to study student and teacher behaviours in response to this. Accordingly, this paper undertakes an investigation based on the Technology Acceptance Model (TAM) to examine academics’ and students’ acceptance of and adoption of e-learning in university education in their roles as universities’ main actors. This paper focuses on teachers and students with no background in ICT, investigating their acceptance of e-learning as a learning method. A seven-point Likert scale questionnaire was systematically developed, validated, and used as a data collection instrument with 450 students and 75 university lecturers from two separate colleges. A clustering sampling method was used in the sampling selection process, and several hypotheses were proposed and tested via the paired T-test. The paper’s outcomes can be classified into three categories: it helps to determine to what extent e-learning is accepted by non-expert users; it provides evidence of new factors that influence application of e-learning, extending the TAM model; and, finally, it provides meaningful recommendations for higher education institutions to utilise before adopting e-learning to maximise acceptance. In particular, the results indicate that academics’ and students’ intention to use e-learning is positively influenced by both perceived usefulness and perceived ease to use.
DC-AC Inverter with Tap Changing Transformer
Authors: Mohsin Mustafa H , Al-Shamaa Nabil K
Published: January 2020

In this paper a new single phase seven and eleven level inverter based on a tap changer transformer is developed to generates seven and eleven non-equal voltage levels from two DC sources. The model of inverter thus presented does not suffer from voltage balancing issues. The DC sources are connected to the primary side of the tap changer transformer with the help of a microcontroller circuit (Arduino UNO), with several semiconductor switches offering sequential modality. At the secondary side of transformer, the output voltage is generative, and Proteus/Software manipulation is performed. This technique reduces the Total Harmonic Distortion (THD) of the output voltage significantly.
Control strategy to improve power transmission capacity from wind farms to weak AC grids
Authors: Nawir M H , Marei M M , Altuma A S
Published: January 2020

—With the increasing connection of large wind farms based on direct driven Permanent Magnet Synchronous Generators (PMSGs) to weak AC grids, the steady state characteristics of such wind farms, particularly those connected to very weak AC systems with a Short Circuit Ratio (SCR) of 1, are important factors for analysis with a view to improvement. In this paper, the issue is thus analysed in order to identify the factors limiting transfer capability from wind farm output. This paper thus presents a simulation model of a wind farm connected to a very weak AC grid, and a vector control strategy is used with respect to the full power converters of the wind farm in order to track current order injected from the converters into the AC system. A supplementary outer loop control is proposed to support grid voltage and to maximise transferred power into the very weak AC grid, based on a droop gain which is allowed to update the reactive power reference for reactive power control for the grid side converter based on changes to the output of the wind turbine, within grid code requirements. The simulation results prove that the proposed control system offers a promising method for addressing challenges arising in active power transmission, and thus increasing transferred active power from such wind farms to very weak grids.
Performance Evaluation of Flux-Switching Permanent Magnet with Modifications to Stator and Rotor
Authors: Barzegari Bafghi Mohammad Hussein , Vahedi Abolfazl , Mohammad-Alikhani Arta
Published: January 2020

A flux-switching motor is a synchronous electric motor in which both field and armature coils are placed on the stator. There are thus three different stator structure types with regard to field excitation: permanent magnet, direct current field excitation, and hybrid. The rotor structure of the motor in this study reflected two types: integrated and multi-piece structure. The permanent magnet flux switching motor with integrated rotor structure offers more advantages and more attention has been paid to this as compared to other electric motors in various industries. The major advantages of this type are high torque density, ease of manufacture, high reliability, and robustness of rotor. However, these flux switching motors have relatively high cogging torque, and while work has been done on reducing the cogging torque and some literature published, most such works have focused on modifying the rotor tooth, skewing the rotor. These works study the effect of rotor shaping on motor performance, while in this paper, new rotor shapes are also considered. Finally, a method is introduced to minimise the cogging torque that has least adverse effect on other effective parameters such as torque density. Using the results of other papers, the finite element method is used to find the best method of rotor shaping in this paper.
Design and Modeling of a Soft Artificial Heart by Using the SolidWorks and ANSYS
Authors: Ali Saad Mahmood , Ali Zahraa Jasim , Abd Mays Mahde
Published: January 2020

Investigating the biomechanical behaviour of a soft artificial heart is a hard task as such things are very complicated in terms of both material properties and geometry. This work focused on developing, designing, modelling and analysing a new generation, low cost, easily operable, full-size, low power consumption, and durable soft artificial heart intended to replace an original heart on a parmanent basis. Numerical simulation and investigation of the artificial heart were implemented using SolidWorks 17 and ANSYS 15.7, with a Multiphysics static structural model, fluent fluid flow (CFX), and fluent fluid poly-flow (CFD) analysis systems used in order to determine the dynamic response and effects of pressurised blood on heart performance during blood flow cycles. The biomechanical modeling and analysis of the soft artificial heart were implemented using the finite element modelling in ANSYS R18.0. To improve and verify the biomechanical performance, Design Expert 11.0 software and a response surface methodology (RSM) technique were used. The simulation results showed that as maximum levels of absolute pressure were applied on the ventricles and air pressurised chambers, the performance of the heart remained secure. The results also showed that strain energy, total deformation, maximum principal elastic strain, stress and fatigue safety factors, and fatigue life all reached thier optimum values when using the SIBSTAR 103T with polyetherimide/silicone (PSN4) Nano-composite elastomers.
Energy dissipation in gabion weirs
Authors: Al-Fawzy A M , Al-Mohammed F M , Alwan H
Published: January 2020

The present study investigates the effect of hydraulic jumps as criteria for representation of the energy dissipation of flow in gabion weirs. A set of 25 laboratory experiments and 188 operation tests were carried out using a laboratory flume with dimensions 10 m long by 0.3 m wide, and 0.5 m high. The tested gabion weir had different five possible lengths, 0.4 m, 0.6 m, 0.8 m, 1.0 m, and 1.2 m, and the filling material used was natural quarry mono-graded gravel in five different sample sizes of average equivalent diameter 11.75 mm, 16.50 mm, 22.00 mm, 31.25 mm, and 43.75 mm. Operation discharge values ranged between 0.7 to 15.0 l/s. The data set was subject to dimensional analysis to generate dimensionless groups, and correlated using the Buckingham Pi-Theorem. The results of this analysis showed that the distance of hydraulic jump has a direct relationship with discharge and an inverse relationship with the diameter of the gravel in the sample. For specified discharges, the distance of hydraulic jump had an inverse relationship with the length of the gabion weir and a direct relationship with the proposed energy dissipation parameter.
Effect of Earthquakes over Time on the Geogrid-Pile Foundation System in Loose Sand
Authors: Al Ghanim Athraa A. , Mohammed Shafiqu Qassun S. , Ibraheem Asma Thamir
Published: January 2020

Researchers and engineers have developed several means to enhance the dynamic lateral stability of civil engineering structures, such as geosynthetic reinforced earth retaining structures to resist excessive earthquake shaking. There is, however, as yet little information about using geogrids with pile foundations under earthquake loadings. This study thus linked a single embedded pile in loose sandy soil with a geogrid, with the system then subjected to two different seismic waves.

The laboratory tests were carried out on single pile with a length to diameter ratio of 25 in poorly graded soil (SP) with a relative density of 30%. The geogrid used in the research was Nelton CE121 geogrid (700×700 mm), which was connected with the pile at a depth of 1/8 of the pile length. The model was then subjected to replications of both the Ali Al Gharbi and Halabjah earthquakes, which hit Iraq in 2014 and 2017, respectively.

It was found that using geogrid with pile foundation reduced the settlement in the pile by about 50% and 90% for the Halabjah and Ali Al Gharbi earthquake forces, respectively. The maximum bending moment was also reduced, with the bending moment ratio at the pile surface for the Halabjah and Ali Al Gharbi earthquakes being 70% and 50% respectively. The settlement ratio increases as magnitude of earthquake decreases.
Fresh and Hardened Properties of Nano Self-Compacting Concrete with Micro and Nano Silica
Authors: Hameed Mohammed H. , Abbas Zena K. , Ali Al-Ahmed Ali Hussein
Published: January 2020

Self-compacting concrete (SCC) has undergone a remarkable evolution recently based on the results from several studies that have indicated the chain of benefits SCC provides. Micro and nano materials used as mineral additives in SCC offer several high-performance properties, and this research studies the effects of micro silica (MS) (10%, used as a reference) and colloidal nano-silica (CNS) (2.5%, 5%, 7.5%, and 10%) on the fresh and hardened properties of SCC. All mixtures were estimated using flow, L-box, and V-funnel tests to examine workability and compressive strength, modulus of elasticity and tensile strength as hardened properties. The use of CNS increased the overall compressive strength compared to the reference mixture, with the average increase for 28 days being 41%. The discoveries of this work offer insight into the creation of volitional mineral admixtures for improving the toughness attributes of SCC, increasing enforcement, and offering a more maintainable and practical material.
Scour Depth at Single Cylindrical Bridge Piers with Debris Jam: An Experimental Comparative Study.
Authors: Al-Awadi Aysar Tuama , Al-Khafaji Mahmoud Saleh
Published: January 2020

Rivers may carry a considerable amount of debris during floods, and the accumulation of this debris around bridge piers can change the hydraulic behaviour of flow fields and influence scour depth development. In this study, the effect of debris jam on scour depth at cylindrical bridge piers was investigated and a comparison carried out for the main existing empirical formulas. A series of 27 tests of rectangular geometry in three different groups according to width, length, submerged depth, and blocked area were studied. The results showed that the accumulation of debris increased scour depth from 10.3% to 62.1%, 22.4% to 103.4%, and 20.7% to 139.7% as the percentage blocked area of debris increased from 2.07% to 6.2%, 5.52% to 16.55%, and 8.96% to 26.89% for groups (1), (2), and (3) respectively. The comparison of the experimental results with the most commonly used empirical formulas revealed general overestimation of scour depth with debris accumulation. The Richardson and Davis (1995) and Lagasse et al. (2009) formulas were the most acceptable methods for scour prediction under debris jams, though further study is recommended for bridge pier scour depth estimation in the presence of debris.
Investigating the effectiveness of geometric and human factors on the severity of urban crashes
Authors: Ayazi Ehsan , Khorsand Ramin , Sheikholeslami Abdolreza
Published: January 2020

Traffic safety is a major priority for multiple relevant organisations seeking to reduce accidents and traffic fatalities; considering the importance of this issue, it is necessary to provide solutions to reduce both the frequency and severity of such problems. The purpose of this study is thus to investigate the factors affecting the severity of urban crashes. To this end, accidents in the city of Zanjan were analysed using a Pearson’s chi-square test with a confidence level of 95%. The dependent variable was accident severity as judged by injury and property damage, and the independent variables were type of collision, general cause of accident, road type, road surface conditions, road geometry, lighting conditions, engine power of the at-fault vehicle, and gender of the at-fault vehicle’s driver. The results showed that side-to-side collisions have the lowest probability of injury or property damage. The highest probability of injury or property damage is caused by speeding. Furthermore, increase in engine power of the at-fault vehicle caused the probability of property damage to increase, and male drivers were found to experience more severe crashes in urban roads than female drivers. Appropriate recommendations were thus provided.
Temperature Effects on the Fatigue Life and Tensile Strength of Structural Adhesives
Authors: Al-Mosawe A , Al-Mahaidi R
Published: January 2020

In recent decades, structural adhesives have become widely used in the field of construction for the purpose of retrofitting existing structures using composite materials such as fibre reinforced polymers (FRP). The available standards for strengthening structures utilise the adhesive properties as listed in manufacturer’s technical sheets. However, members with adhesively bonded CFRPs are sometimes exposed to loadings or conditions that may differ to the scenarios used to measure these material properties. Steel and concrete bridges are usually exposed to cyclic loading associated with elevated temperatures, for example, while the manufacturer’s technical sheets provide material properties under quasi static loading and ambient temperatures. There is thus a lack of understanding of the properties of adhesives under more difficult conditions that may lead to issues in predicting the design strength of composite elements. This paper presents a series of experimental tests to investigate the adhesive properties under both medium temperature (25 and 40°C) and cyclic loading, with adhesives cured under two curing temperatures. All specimens and tests were developed according to ASTM-D638. The results showed significant effects of temperature on the tensile strength and fatigue life of adhesives, as measured by monitoring the number of cycles until failure; the number of cycles was increased by 8 times for two types of structural adhesives cured under high temperature and tested under normal temperatures of 25°C.
Influence of anchorage systems on externally-bonded CFRP sheets used for flexural strengthening
Authors: Al-Atta B , Kalfat R , Al-Mahaidi R , Al-Mosawe A
Published: January 2020

Strengthening with carbon fiber-reinforced polymers (CFRP) has become one of the most significant methods of enhancing the flexural strength of reinforced concrete members. Extensive research has shown that externally-bonded CFRP sheets tend to debond from the soffit of the concrete members at much lower strains, compared with CFRP rupture strain. Different types of anchorage system have been developed to prevent or delay the debonding type failure, which leads to a higher utilisation of the CFRP sheets before failure occurs. This paper summarises some of the most efficient types of anchorage systems that have shown significant enhancement in terms of increasing the flexural bending capacity and the ductility of CFRP strengthened members. The study also presents a newly-developed type of anchor, known as a patch anchor, which has shown great effectiveness when used for shear applications. The influence of patch anchor on flexurally-strengthened slabs is investigated, where this anchorage type is trialed, and its effectiveness is discussed.
Experimental investigation of the structural behaviours of self-compacted reinforced concrete hollow beams with in-place circular openings
Authors: Hassan Saif A , Hemzah Sadjad A , Alyhya Wajde S
Published: January 2020

This paper aimed to experimentally investigate the structural conduct of self-compacted concrete hollow beams with various in-place openings. For this purpose, ten reinforced concrete hollow beams were tested under two concentrated and symmetrical loadings. The primary parameter in this study was the location of the openings, and specimens were divided into two groups in addition to the control beam: group one included six beams with openings in front or front and rear of the web, while the second group contained three beams with an opening in the bottom flange of the beam. The results showed that all reinforced concrete specimens suffered from higher deflection and stiffness reductions. The load-carrying capacity was decreased in ranges between 5.2% and 16 % for group one and 5.5 % to 9 % for group two compared to the control beam. A reduction was also observed in the ductility index values, ranging from 2.8 to 1.5 compared to the control beam.
Laboratory Study of Lateral Load Capacity and Behaviour of Short Piles in Clayey Soil.
Authors: Aljanabi Hijran Aboud , Bazaz Jafar Bolouri
Published: January 2020

This research is an experimental study investigating the lateral loading capacity of piles in clayey soil. Important factors considered in this study included pile diameter, embedded length of pile, effective unit weight, and degree of saturation of soil, which were studied for their effects on the lateral loading capacity of short driven piles. The experimental study involved testing six specimens in the laboratory, each made of galvanized iron of 21.7 and 27 mm diameter and L/d (embedded length/diameter) ratios of 10, 14, and 18. The specimens were subjected to lateral loadings while embedded in clayey soil with effective unit weights of 13, 15, and 15.6 kN/m3 and degrees of saturation of 30, 41 and 97%, to simulate true pile behaviour. The obtained pile responses were then plotted as force-displacement diagrams. The varying parameters were thus diameter and embedded depth of pile, effective unit weight, and degree of soil saturation. The results of this experimental study on the behaviours of the piles under the influence of lateral loading in the clay were also compared with the predicted lateral capacity of the piles based on work by other researchers. Moisture content and degree of saturation were found to have the greatest effects on pile behaviour. This study thus aids understanding of the behaviours of short piles embedded in clayey soil under lateral loading to allow designers to take practical steps and choose an appropriate method when designing a pile.
Temperature Susceptibility of Modified Asphalt Binders
Authors: Abed Yasameen Hadi , Abedali Al-Haddad Adabdulhaqh H
Published: January 2020

Temperature is considered here as an important measurement affecting the behaviour of asphalt cement. The relationships between temperature and viscosity for ten pure and modified asphalt cements were thus assessed using traditional methods (including penetration, and (R&B) softening point) and dynamic shear rheometer (DSR) and rotational viscometer (RV) tests. The temperature used for testing were (25˚C), (120 to 195 ˚C), and (4 to 70 ˚C) for traditional, RV, and DSR tests, respectively.

The effects of test type, asphalt cement type, modifier type, and content, on temperature-susceptibility were investigated. The results showed that using activation energy (Ea
) for flow allowed discernment of asphalt cement’s susceptibility to temperature variation, and that the addition of modifiers (SBS, BR, and BG) to asphalt cement increased the Ea
indices. Higher increment rates in Ea (23.57%) were caused by the addition of BR, while reduced VTS was seen with the addition 9% BR, and 5% and 7% SBS, with reduction rate of 44.138%, 15.994% and 15.241%, respectively, due to reductions in viscosity changes with variation in temperatures, while the addition of 0.075% BG Plus increased VTS by 2.496% compared with base asphalt binder.
Field investigation on the lateral resistance of railway tracks with frictional sleepers
Authors: Zakeri Jabbar Ali , Mirfattahi Behrooz
Published: January 2020

Tie type is one of the most effective parameters for changing the lateral resistance of ballasted track. In this study, the lateral resistance of an existing curve-to-lateral movement is investigated in the field in two conditions: with simple mono-block concrete ties (B70) and with friction concrete ties (B70F). After that, lateral resistance is measured through the panel displacement method. The results show that the lateral resistance of the railway track increases by approximately 67% with the use of friction concrete ties (B70F) instead of standard mono-block concrete ties (B70).
Architectural Mimetism Between Heritage and Technological Advancement
Authors: Alawsey Waleed S. , Al-Dulaimi Hiba A.
Published: January 2020

The rapid technological progress, media and marketing of urban development has affected the features of contemporary Arab architecture in general and Iraq in particular, in terms of designing either regarding to the local identity or regardless to it, so this research tends to study and analyze a group of architects who constantly work on local projects in Iraq to mimic those who do it in harmony with the local identity, and those who work on globalized basis preparing their designs of modern technological references without taking into account the local identity, neglecting the spirit of heritage and the possibility of making an mimetism between heritage and modernism, to produce high-tech designs, performance forms and attributes that bear the spirit of heritage and mimics the identity of humans making it the highest value in design as humans are the user of this new urban environment.

This research focuses on the certain definition of the term mimetism and the mechanism used to apply it in terms of architectural design thoroughly then drawn conclusions from the practical study to illustrate what have been learned through carrying out the study and analysis of those projects along with general conclusions for the research as a whole.
Application of a Solar Chimney Power Plant to Electrical Generation in Covered Agricultural Fields
Authors: Abdul Wahhab Hasanain A. , Kattea Al-Maliki Wisam Abed
Published: January 2020

Greenhouses are an ideal plant production environment, providing high quality products in all seasons of the year and removed from climatic influences such as wind, frost and rain. However, this type of farming involves costly construction, and it is necessary to consider using it in other aspects, in addition to agriculture. The purpose of the current work is to study the possibility of using a solar chimney power plant (SCPP) in the generation of electric power, thereby meeting the need for energy in agriculture, including lighting, pumps, drip irrigation and other applications. This paper describes an analytical study of solar chimney power plant in a greenhouse environment. The investigation was based on experimental calculations to identify out power from varying the air flow intensity inside the farm, depending on its conditions. The modelling was carried out in an ANSYS environment and the simulation of solar plant used a FLUENT k-ε Module for solving and post-processing the problem. Results showed that a solar chimney power plant, in which the chimney height and diameter were 20 m and 0.3 m, respectively, and the dimensions of the green farm collector 70 m × 50 m, could produce a monthly average of 1.31~2.42 kW electric power throughout the year.
Simulation and Modeling of Tower Diesel Power Station in Samawah Using Finite Element Method with MATLAB and COMSOL Programs
Authors: Azziz Haider Nadhom , Rashid Farhan Lafta , Hussein Hasan Qahtan
Published: January 2020

In this paper we present work that explores governing equations for heat transfer and fluid dynamics, and we describe and discuss different forms for such equations, that can be applied to formulations of the discontinuous finite element. In general, heat transfer and fluid dynamics problems are categorized as boundary value problems. Thus, the desired initial and final boundary conditions for solving these equations are given in a simulation of a modeling tower for a diesel power plant in Samawah, Iraq, via the finite element method using MATLAB and COMSOL programs. As vertical expansion is limited by the frictional repression of the benthos, an effective vertical force is generated in the tower. If the effective vertical force overtakes the buckle initiation force, the tower will undergo Euler buckling to qualify the resulting high vertical forces in the tower wall. We present numerical results for a mesh in Multiphysics of the lower and upper parts for the tower; an analytical model was built of the upper portion of the tower.
Analytical Assessment of the Effects of Blade Cone Angle on the Aerodynamic Performance of the Horizontal Axis Wind Turbine
Authors: Hachim Ghanim M. , Mahdi Jaafar A.
Published: January 2020

In this research, the performance of a horizontal axis wind turbine (HAWT) is investigated, considering the cone angle effects. In a HAWT with an ordinary pattern, all blades are located in one plate and the cone angle of the plate is zero. In the design of HAWTs, to prevent contact between the blades and the turbine’s tower and considering the aero elasticity effects, the blades are installed on the shaft of the rotor using a cone angle, which has effects on the turbine’s performance. We investigated the aerodynamic performance of the HAWT according to cone angle deviations, numerically. With a change in the blade’s plate pattern, a cone-shaped volume is created. In this condition, the projected blade’s length gets smaller and the blade’s sections (vertical to the wind) become larger. The geometry of these sections was obtained with AutoCAD software. The performance of the turbine was analysed with Qblade software, and the results compared with each other. The output results of Qblade for the situation, in which the cone angle is considered, equal to the projected blade’s length and the new sections for the projected airfoils within the zero cone angle investigated and compared. This research was carried out for two conditions: a blade with a constant chord and a blade with different chords through the length of the blade. The creation of the cone angle may be suggested as one approach for controlling the wind turbine.
Effect of Process Parameters on the Surface Quality of Machined Aluminum and Steel Products
Authors: Salman Zaman W. , Ugla Adnan A.
Published: January 2020

In a turning process, surface roughness depends on machining process parameters. The aim in this work is to improve the quality of the machined surface of the by controlling the main input parameters of the turning process for aluminum and steel materials. The effect of the machining parameters on surface roughness was studied using the orthogonal L9 Taguchi method. Four process parameters chosen were the length of the specimen (L), diameter of the specimen (D), feed rate (F), and depth of cut (T). The optimization method was performed using the signal to calculate noise ratio (S / N) for the changing response of all experiments. The results were analyzed using the analysis of variance (ANOVA). The main conclusion of this work is that F and T are the most important factors and can influence the machined surface quality in terms of surface roughness, whereas the other factors are insignificant. The minimum surface roughness for aluminum is 1.03 μm and 5.02 μm for steel specimens, which were obtained using a more suitable set of parameters with values of T 0.5 mm, F 0.5 RPM., L1000 mm, and D 40 mm.
The Effect of Heat Treatment Conditions on the Mechanical Behavior of Ni-Ti Shape Memory Alloys
Authors: Al-Helli Ali H. , Abed Abdulrahman N. , Abdullah Asmaa M.
Published: January 2020

Ni-Ti shape memory alloy (SMA), and its alloys have been widely used for medical, mechanical and electrical applications. In this study, a (Nitinol) Ni-Ti alloy medical plate was prepared and cut using a wire cut machine. Eight samples were heat treated at 800°C and used for heating samples for 30 min and 60 min at this temperature, then cooled in four media: furnace, water, air, and ice bath. Micro-hardness and microstructure measurements were taken, as characterization techniques, to investigate the effect of cooling rate on mechanical properties. Micro-hardness results showed the HV is 316.36 HV at ice cooling rate for 800 °C and 60 min heating time, and 275.5 HV for 800 °C heating for 30 min and ice cooling media. The results show the correlation between cooling rate and properties of the alloy.
Effects of Pt Content on Room-Temperature Hydrogen Sensing Characteristics of Pt-SnO2 Nano-Composite Ceramics
Authors: Wang Caochuang , Li Pengcheng , Hu Yongming , Xu Liqun , Zhou Zhen , Chen Wanping
Published: January 2020

A series of Pt-SnO2 nano-mixtures with 0, 0.25, 1 and 2.5 wt% Pt separately were prepared using SnO2 nanoparticles and H2PtCl6. Through pressing and sintering, Pt-SnO2 nano-composite ceramics with Pt nanoparticles well dispersed have been successfully prepared from the nano-mixtures. Their resistance is found to increase monotonously and greatly with increasing Pt content, which is increased by three orders of magnitude when Pt is increased from 0 to 2.5 wt%. All those samples with a Pt content show distinct responses to hydrogen at room temperature, while their hydrogen sensitivity and their recovery time both decease dramatically with increasing Pt content. These results strongly suggest that Pt as a catalyst promotes oxygen chemisorption on SnO2 and the reaction between hydrogen and oxygen at room temperature. Pt thus has catalytic effects on both hydrogen and oxygen, which leads to quite complicated effects of Pt content on the room-temperature hydrogen sensing behaviors of semiconducting metal oxides.
Preparation and Characterization of Neopentyl Glycol/Epoxy Resin Shape-Stabilized Phase Change Material for Thermal Energy Storage
Authors: Meng Duo , Zhao Kang , Wang Anqi , Zhao Wei
Published: January 2020

Neopentyl glycol is a kind of solid-solid phase change material for thermal energy storage. In order to overcome volatilization weight loss caused by the high saturated vapor pressure of neopentyl glycol, epoxy resin was chosen as the encapsulation matrix to inhibit the volatilization of neopentyl glycol when it happens phase change or works in a relatively high temperature environment. The micro morphology analysis indicated that the neopentyl glycol was encapsulated evenly in the epoxy resin matrix. These two components had no chemical reactions and combined with each other by the physical encapsulation. Phase change temperature and latent heat of the composite was measured as 41.26°C and 57.04 J/g respectively, which proves the thermal heat storage performance of the neopentyl glycol was not influenced by the adding of epoxy resin. Meanwhile, attributed to the effective encapsulation and protection by epoxy resin, volatilization weight loss of the neopentyl glycol in the composite decreased significantly and behaved good thermal stability and reliability. After 100 times thermal cycling test, the composite hardly changed in the thermo-physical properties. Thus, the prepared neopentyl glycol/epoxy resin composite phase change material is supposed to be a potential and promising functional material for the applications in low temperature building energy conservation and solar energy storage.
Magnetism of Undoped ZrO2 Nanoparticles Deposited by Plasma-Gas-Condensation Technology
Authors: Zhou Wenxin , Lin Kangqi , Wang Laisen , Luo Qing , Peng Dongliang
Published: January 2020

The magnetic properties of undoped ZrO2 nanoparticles (NPs) deposited by plasma-gas-condensation technology were studied. The as-prepared ZrO2 NPs with controllable particle sizes (6-13 nm) presents tetragonal phase which was hardly acquired by traditional methods at room temperature. The as-deposited ZrO2 NPs were annealed at 300 to 1000 °C in air or mixed gas of Ar (95%) + H2 (5%) for 3 h, respectively. XRD results show that the phase of ZrO2 NPs gradually transformed from tetragonal to monoclinic with increasing the annealing temperature. The magnetic results of ZrO2 NPs under all annealing treatments were paramagnetic, which are different with the diamagnetic or ferromagnetic ones, also different from magnetic property changed after annealing in some other works.
Effect of Rolling Processing on Mechanical Properties of Material Cr12
Authors: Liu Yichen , Li Taoyuan , Zhang Haiquan , Guo Peiquan
Published: January 2020

The rolling process changes the mechanical properties of the specimen’s surface material, and it also directly affect the fatigue strength and service life of the workpiece. The effects of rolling parameters on surface residual stress, microhardness, surface roughness and surface microstructure are studied by rolling test of Cr12 specimens. After rolling, the residual stress on the surface of Cr12 specimens changes from tensile stress to compressive stress, and the maximum compressive stress is -216MPa. With the increase of contact stress and rolling passes, the residual compressive stress increases at first and then remains stable. Rolling processing can effectively improve the surface hardness of specimens up to 30%, and the surface roughness can be reduced by 25%-67%. The fine grains aligned with the rolling direction, and the 50-60 μm grain refinement layers were observed, which resulted in the changes in the surface mechanical properties of the specimens.
Synthesis and Adsorption Properties of Insoluble Starch Xanthate (ISX)
Authors: Li Haihua , Zhang Lihui , Gao Yuhua , Liu Zhenfa
Published: January 2020

Starch xanthate was synthesized from corn starch and CS2 under alkaline condition. The effects of catalyst dosage, CS2 dosage and reaction temperature on sulfur content and copper ion removal rate were studied by single factor experiments, and the structure of the product was characterized by FTIR, SEM and XRD. The results showed that the optimum synthetic condition of ISX was NaOH dosage 16 mL, CS2 dosage 2.5 mL, reaction temperature 35 °C and reaction time 2 h. The sulfur content of ISX synthesized under this condition was 7.54%, the removal rate of copper ion was 90.5%, and the adsorption capacity of ISX was 90.0 mg/g.
Regenerated Bamboo-Derived Cellulose Fibers/RGO-Based Composite for High-Performance Supercapacitor Electrodes
Authors: Wang Tianhao , Zhang Wentao , Yang Shujuan , Tian Weiqian , Zhang Liping
Published: January 2020

Bamboo-derived cellulose fibers/RGO carbon aerogel composite was prepared by using a facile aerogel-based method, in which bamboo pulp fibers were dissolved and incorporated in an ionic liquid system, and RGO was introduced by thermal reduction approach. The obtained bamboo-derived cellulose fibers/RGO carbon aerogel composite shows a large specific surface area, and excellent electrochemical performance. When the GO content was 2.5 wt%, the obtained composite showed a high specific surface area of 1957 m2/g, and high specific capacitance of 351 F/g in 6 M KOH electrolyte solution even with a more than 90% capacitance retention at a high scan rate of 200 mV/s. The bamboo-derived cellulose fibers/RGO composite electrodes show the low equivalent series resistance of 5.0 Ω and small charge transfer resistance of 0.30 Ω which further demonstrate the excellent electrochemical behaviors.
Comparison in Chemical Composition of Lime Binders between Several Typical Ancient Buildings in China
Authors: Zhao Peng , Zhang Xiuzhi , Qin Lei , Zhang Yunsheng , Ren Hongwei , Lv Yinghui , Liu Gengle
Published: January 2020

This paper aims to compare the chemical and phase compositions of lime binders in ancient buildings. To this end, X-ray diffractometer (XRD) and FT-IR testing were used to analyse the representative samples by sampling the lime-based binding materials of several typical ancient buildings in China. The test results showed that the lime binder contained residual glutinous rice amylopectin; just because of this inorganic and organic synergistic effect of glutinous rice and lime can the lime binders have excellent properties. This provides a theoretical basis for the subsequent study.
Design of A Drive Scheme for Untethered Magnetic Manipulation Polishing
Authors: Zhou Xiaoqin , Wang Haocheng , Sun Baoquan , Wang Yifei , Wu Xiaoyang
Published: January 2020

Based on the untethered magnetic manipulation polishing device, this paper proposes a reasonable driving scheme, which makes the teleoperation process of the device more stable and easy to implement. The change of the position of the external permanent magnet can drive the internal polishing tool to produce corresponding changes. The comparison is made between the axial and radial driving modes, and finally the axial driving mode is selected for control.
Seismic Risk Probability Assessment of Frame Structures Based on Incremental Dynamic Analysis
Authors: Yang Beibei , Wang Zhitao , Ma Donghui
Published: January 2020

To assess the seismic risk probability of frameworks in different seismic fortification intensity zones in China, three fortification intensity framework models-specifically, 6 (0.05 g), 7 (0.1 g), and 8 (0.2 g)-were established as the research objects. The incremental dynamic analysis method was used to conduct a structure seismic fragility assessment, in which the fragility curves as well as the damage probabilities under certain peak ground accelerations were obtained. The risk probabilities of all the seismic damage levels of the frameworks in the next 50 years were calculated using the Monte Carlo method based on a study of the seismic hazard of different fortification intensity zones. The results indicate that, in the next 50 years, the risk probabilities of fortification intensity framework models 6, 7, and 8 exceeding “serious damage” were 1.92, 4.25, and 8.28%, respectively. Additionally, the risk probabilities of the models having a damage degree of “collapse” were 0.14, 0.43, and 1.07%, respectively. Based on the risk probability of the structure, the risk level is classified. This study forms the basis for the comprehensive evaluation of building seismic damage risk and can be used as a reference for the development of building seismic disaster prevention countermeasures.
The Super-hard Cutting Tools’ Thermal-cracks Monitoring System Based on Multi-agent Technologies
Authors: Guo Caifen , Dong Zhi
Published: January 2020

A thermal crack monitoring system of super-hard cutting tools was set up based on agent technologies. The system structure was designed, together with each agent’s workflow, inter-relationship among agents, and their communication mechanisms. If working properly, the system would realize the following functions, data collecting and retrieving, crack conditions monitoring, and resources state inspection and management.
Design and Implementation of a New Circuit Maintenance Training Platform
Authors: Zhou Zelong , Shao Xichun , Yang Zhuo , Zhu Xiaochun
Published: January 2020

This paper designs a circuit maintenance platform for the artillery system. It can read or simulate the important node data of the artillery system in real time online or offline, and provide the basis for the artillery maintenance inspection. It can also be used as a daily teaching operation demonstration platform; analog data detection read and fault demonstration process.
Development Model and Analysis of Single Well Circulating Shallow Geothermal Energy Based on Mathematical Modeling
Authors: Yu Liwu
Published: January 2020

Shallow geothermal energy has been used as an important energy because of its wide distribution, large reserves, rapid regeneration and high utilization value. As a new exploitation method of shallow geothermal energy, single well circulation has been widely concerned. In this paper, the mathematical model of single well circulation mining mode is analyzed from the point of view of mathematical modeling, and the practical problems encountered in the process of single well circulation mining are considered by using concepts of conceptual model, mathematical equation and numerical calculation method, and hydrogeology and hydrodynamic process are considered by assigning specific constants and variables. The influence of heat and mass transfer on geothermal energy exploitation. Based on the above model, the problems encountered in shallow geothermal exploitation are analyzed and discussed in depth, and the corresponding conclusions are drawn. To solve the current problems encountered in shallow geothermal energy exploitation, and provide a theoretical basis for the future development and utilization of new energy.
Modeling and Simulation Analysis of Pre-Valve Compensation of Flow-saturated Resistant System
Authors: Luo Yanlei , Chen Wang , Chi Baokun
Published: January 2020

The load-sensing pre-valve compensation technology is widely used in the single-pump multi-acting mechanism composite motion circuit. Due to the use of multi-valve inlet valve front compensation, its structure is simple, only need to set a two-way fixed-rate valve, but the flow saturation conditions cannot be automatically adjusted. Through an in-depth theoretical analysis of the anti-saturation mechanism, composition and control strategy principle based on automatic flow reduction (AVR), the AMESim model of the system is established, and the anti-flow-saturation output characteristics of the system are obtained under different operating conditions by numerical simulation means, and the results show that the system can solve the problem of flow-saturation. It provides some technical reference for the design of the load-sensing pre-valve compensation system.
Research on A New Type Topology of 4-Quadrant Converters
Authors: Pan Dawei
Published: January 2020

In consideration of the demerits of the traditional four-quadrant converter whose operating voltage of the dc side is very high, a new type topology converter is proposed whose topology belongs to quasi-buck topology and the voltage of the dc side is reduced by about 50%. Therefore this kind of four-quadrant can be used in the lower voltage filed. The modelling of the converter is described in this paper. The validity of the converter topology and the model along with the theory is proved by MATLAB simulation and the experiment result.
Energy levels of graphene magnetic circular quantum dot
Authors: Belouad Abdelhadi , Lemaalem Bouchaib , Jellal Ahmed , Bahlouli Hocine
Published: January 2020

We study the energy levels of graphene magnetic circular quantum dot surrounded by an infinite graphene sheet in the presence of an electrostatic potential. We solve Dirac equation to derive the solutions of energy spectrum associated with different regions composing our system. Using the continuum model and applying boundary conditions at the interface, we obtain analytical results for the energy levels. The dependence of the energy levels on the quantum dot radius, magnetic field and electrostatic potential is analyzed for the two valleys K and

K
′

. We show that the energy levels exhibit characteristics of interface states and have an energy gap.