bluuebunny/crossref_metadata_2025 huggingface dataset:
Weight Optimization of Thick Plate Structures Using Radial Basis Functions Parameterization
Authors: Marzbanrad Javad , Rostami Pooya
Published: January 2020

This study sought to optimize the weight of thick plate structures with topology optimization. Topology optimization is a numerical method for identification of voids in the design domain, to aid weight and material reduction. The level set approach is a new method in topology optimization. In this work, the radial basis functions level set approach is used to parameterize the continuum domain. The radial basis functions are used to parameterize the level set functions, which comprise axial symmetric, real value functions. These functions are suitable tools for function approximation. Thick plates are one of the most useful and familiar geometries in structural and mechanical engineering applications. Topology optimization of such structures would be very useful to identify efficient and lightweight plate structures. In this paper, the effectiveness of the parametric level set approach in topology optimization of clamped plate is demonstrated. The results show smooth boundaries and there are no intermediate densities, which constitutes a major advantage.
Effect of Axial Profile Modification on the Characteristics of a Finite Length Misaligned Journal Bearing
Authors: AL-Dujaili Zahraa A. , Jamali Hazim U. , Al-Saadi Moneer
Published: January 2020

Misalignment in journal bearings is a common industrial problem which affects the general performance of the bearing. This includes a significant effect on the load carrying capacity of the bearing and the change in the level and shape of the pressure distribution. There are many causes for the presence of misalignment in the practical uses of the journal bearing system, such as deflection of the shaft under high levels of load, manufacturing errors, installation error, and others. In the case of severe misalignment levels, a sharp drop in the lubricant film thickness or even a direct contact may occur between the shaft and the bearing at the edges of the bearing. This paper considers such extreme cases of misalignment, where the introduction of bearing axial profile modification to prevent edge contacts is investigated in detail. A general 3D model of misalignment for the case of a finite length bearing is considered in the analyses, where the Reynolds equation is solved numerically based on the finite difference method. The results reveal that the use of profile modification leads to an improvement in the levels of film thickness and an increase in the load-carrying capacity of the bearing.
The Contribution of Capacity Credit on Reliability of Generating System Adequacy
Authors: Kadhem Athraa A.
Published: January 2020

A conventional generating unit is more reliable than a wind energy conversion system (WECS), in terms of capacity value. It performs an essential role in supplying reliable energy for electrical systems. Wind energy is considered a fundamental alternative source for electrical power generation. So far, it is difficult to secure wind speed data that covers a long period and is suitable for wind energy generation assessment. Generating wind power often includes uncertainties, due to the stochastic nature of wind speed. Hence, the capacity credit (CC) of the WECS is intermittent in nature. There are numerous approaches that can be adopted for evaluating the CC of wind power generation, for designing and planning new investment capacities. This paper examines the use of capacity credit from the WECS to obtain the load capacity benefit ratio (LCBR) for the reliability of power systems. To calculate CC, the IEEE-MRST-79 is used to elucidate the proposed technique. A sequential Monte Carlo simulation (SMCS) technique is used to determine the reliability of the generating systems which includes the WECS.
Investigation of Silicon Nanowires Produced by Metal-Assisted Chemical Etching Method
Authors: Alher Murtadha A. , Mosleh Aboozar , Banihashemian Seyedeh Fahimeh
Published: January 2020

Silicon nanowires (SiNWs) have a strong potential in many fields. The investigation of fabrication methods for SiNWs has attracted much attention in semiconductor applications. This paper proposes a metal-assisted chemical etching (MACE) method as a low-cost and simple method for fabrication of SiNWs. This method is based on the electroless metal deposition (EMD) principle. We have studied the conditions of MACE method for fabrication of SiNWs on (100) p-type silicon wafer. A 0.005 AgNO3 and 4.8 M HF solution is used for metal-assisted depositing of the silver nanodots. The etching process is achieved by etchant solution consisting of 4.8 M HF and different concentrations of H2O2. The effect of etching parameters, such as etching time, H2O2 concentration and the dipping time, are investigated. Taguchi with L9 orthogonal array is used by software package MINITAB 17 for designing the experiments. The results of scanning electron microscopy (SEM) observations shows the formation of the silicon nanowires. The effect of the different conditions on the size of the SiNWs is analyzed using S/N ratio and ANOVA approach. The results show that etching time was the most significant factor in the SiNWs fabrication.
Hot Press Bonding of Aluminum Alloy AA6061-T6 to Polyamide and Polyamide Composites
Authors: Tolephih Moneer H. , Abood Adnan N. , Saad Hussein M.
Published: January 2020

In this study, aluminum alloyAA6061-T6 was joined by a hot press process with three types of material; polyamide PA 6.6 (nylon), 1% carbon nanotube/PA6.6 and 30% carbon fiber/PA6.6 composites. Three parameters were considered in the hot pressing; temperature (180, 200 and 220°C), pressure (2, 3, 4, 5 and 6 bar) and time of pressing (1, 2, 3, 4 and 5 minutes for 200ºC, and 0.25, 0.5, 0.75, 1 and 1.25 minutes for220ºC). Applied pressure has great effect on shear strength of the joint, corresponding to bonding time and temperature. Maximum shear strength was 8.89MPa obtained for PA6.6 at bonding conditions of 4 bar, 220ºC and 0.75 minute. For 30% carbon fiber/PA6,6 shear recorded was 8MPa at 4 bar, 220°C and 1 minute, while 1% carbon nanotube/PA6.6 was registered at 8MPa at 4 bar, 220ºC and 0.75 minute. Mechanical interlocking of polyimide in anodizing surface is 8μm approximately. The melting point and glass transmission temperature of polyimide and composites are decreased after hot pressing.
Spatial-Temporal Analysis of Land Use and Land Cover Change Detection Using Remote Sensing and GIS Techniques
Authors: Fahad Karar H. , Hussein S. , Dibs Hayder
Published: January 2020

Remote sensing has become a central factor in approaches to managing natural resources and observing environmental fluctuations. Urban development has brought severe losses of farming land, vegetation land and water bodies. Urban sprawl is responsible for a variety of urban environmental issues including reduced air quality, increased local temperature and reduction in water quality. In this study, we have taken the city of Baghdad as a case study and explore the land use and land cover variation that took place over approximately 28 years from 1990 to 2018. Remote sensing practice was implemented to analyse the city of Baghdad’s land cover and land use changes throughout the study period. Landsat TM and OLI 8 images of Baghdad were collected from the USGS Earth Explorer website. Having pre-processed the image, we used supervised classification to categorize the images in different land cover classes. The study region was classified into five categories: urban area, water bodies, vegetative area, barren land and wetland. The accuracy assessment of classification we obtained was 85.11% and 88.14%. From these results, change detection analysis shows that urban area and soil land levels have gone up by 3% and 20%, respectively. In another area the vegetation has diminished, wetlands and water bodies have also decreased by 5%, 17%, and 1% respectively.
A Wireless Warning System using a Programmable Intelligent Computer
Authors: Farhan Hameed R , Shahadi Haider I , Ghazi Suleiman A , Mohsin Sajjad H , Taherinia Amir H
Published: January 2020

The problem of preventing unauthorised persons from accessing specific places has become an interesting research field. This study proposes a warning system to alarm the owner about any unauthorised attempt to access a secure gate. In the proposed system, the classic alarm circuits that use 555 timers or operational amplifiers are replaced with a simpler and more reliable electronic circuit that includes a small microcontroller chip known as a Programmable Intelligent Computer (PIC). The PIC is programmed to perform sense any touch and produce an alarm signal (buzzer sound), or to send a text message and/or phone call. Implementation of the system demonstrates the superiority of PIC-based circuit over rudimentary electronic circuits in terms of cost, size, complexity, reliability, and system updates.
Algorithm for Greening Big Data Networks in Iraq Under Veracity Dimension
Authors: Mohammad Ali Howraa M. , Kod Muayad Saleem , Al-Salim Ali M. A. , Al-Amiri Caesar
Published: January 2020

This work examines ways to improve energy efficiency in big data networks in Iraq under the veracity dimension by designing an IP/WDM Network in Iraq for processing big data and developing an algorithm that condenses the distinctive features of veracity. The analysis is based on preparing big data chunks for progressive processing after performing cleansing operations as proposed in this work. This is done in Processing Nodes (PNs) that consist of several servers and their associated network equipment, such as switches and routers. The PNs are distributed in the network for each city, and the cleansed data is handled at each PN, reducing the size of valuable data to be transmitted. Each cleansed chunk is also stored in a Backup Node (BN) for future use. Around a 50% power saving is achieved using this technique compared to the traditional method with no progressive processing.
Design of a low noise amplifier for L-band GPS applications
Authors: Alali Mohammed J , Tukkee Ahmed S , Zarkani Mahmood K
Published: January 2020

The low noise amplifier (LNA) is a key part of any receiving system to prevent signal degradation due to different types of noise and the need for long transmission. This paper describes the procedures to design an LNA using a commercial SiGe hetero-junction bipolar transistor (HBT), BFP640, from Infineon Technologies. The amplifier, which satisfies certain specifications, may then be used to strengthen the L2C second civilian GPS signal. The design process was carried out using a powerful microwave CAD package, Advanced Design System (ADS), by Keysight Technologies, which provides a complete RF circuit design facility. The LNA was designed to meet the desired specifications of a low noise figure less than 1 dB, power gain of grater than 20 dB, and output voltage standing ratio (VSWR) of less than 2. The centre frequency used was 1.227 GHz, with an operating bandwidth of 40 MHz. This work thus presents a prototype model that can be readily implemented based on the calculated components of matching networks, as the simulation results demonstrate that the amplifier circuit satisfies the desired requirements.
Design and Performance Analysis of a Bus-Bar Transmission System Protection Scheme Using MATLAB/SIMULINK
Authors: Jawad Haider H , Raheem Mohammed S A.
Published: January 2020

Protective systems form an important part of all electric power networks, making it of major importance to study the performance of these systems. This paper deals with the design and simulation of a bus bar protection scheme using MATLAB/SIMULINK for a 132 kV section of the Karbala transmission network, which is used as a case study for the paper. A performance analysis of a three phase to ground fault is analysed within the simulated system, in which a differential relay is used as the main protection element and an overcurrent relay is used as backup protection.
A modified shank for below knee prosthesis
Authors: Ismail Mahmud R , Kahtan Yassr Y , Abbas Saif M
Published: January 2020

A below knee (BK) prosthesis is a device used to compensate for missing limb segments in patients with BK amputations as an aid for locomotive and other daily activities It consists of three main parts: socket, shank, and artificial foot. The shank is merely a shaft of a suitable length to serve as a frame structure to transfer biomechanical forces between the socket and foot. In traditional BK prostheses, the shank is made from rigid metallic or composite material tube (Teflon), while in the current work, a modified version is suggested with internal stiffness and damping characteristics to act as energy storage and shock absorber. A mathematical model was thus employed to analyse the impact behaviour from walking gait, and the main parameters studied were the effective mass of impact, loading rate, and knee pre-swing angular velocity. The modified prosthesis was tested with a BK amputation patient and compared with a traditional prosthesis in force platform and treadmill tests. The results showed some improvement in patient gait parameters; at stance phase, it smoothed the GRF curve; at heel strike, both the effective mass of impact and loading rate increased by 16% and 22%, indicating good impact reduction, and at pre swing, it increased the initial flexion angle and angular velocity by 13% and 15%, respectively, enhancing the swing phase.
Using NMR, Core Analysis, and Well Logging Data to Predict Permeability of Carbonate Reservoirs: a Case Study
Authors: Kadhim Fadhil S. , Imran Ahmed Mousa , Rasool Yaseen F.
Published: January 2020

Fluid flow through porous media is a function of permeability for petroleum and gas reservoirs. This study investigated the distribution of permeability in the Mishrif formation in the Nasiriya oilfield. The value of effective porosity was obtained from well log data and used to predict permeability using three methods: applied empirical correlations using interactive Petrophysics (IP) software (Version 3.5), core data measurements, and nuclear magnetic resonance (NMR). Nasiriya oil field is one of the large oil fields in southern Iraq, and the Mishrif formation, the area of the case study, consists of the following units from top to bottom: a cap rocks unit; the Upper Mishrif (unit 1); a shale unit; the first reservoir unit (2), a Barrier rocks unit; and the second reservoir unit (3). A 3D model was built by using Petrel software (2009), and the LAS files used to digitize the contour map of the reservoir layers were obtained from Didger3 software. The total number of 3D grids in the model was 5,394,480, with 336 grids in the I direction, 169 in the J direction and 95 in the k direction. Scaling up was done by using the geometric method for permeability, and sequential Gaussian simulation was used in the distribution of petrophysical properties. The results of distribution showed the importance of each zone and the best permeability value was recorded in the second reservoir layer, which varied from 1 md to 100 md.
Using the Leopold Matrix Procedure to Assess the Environmental Impact of Pollution from Drinking Water Projects in Karbala City, Iraq
Authors: Al-Nasrawi F A , Kareem S L , Saleh L A
Published: January 2020

The Environmental Impact Assessment (EIA) procedure is designed to identify and predict the impacts of bio-geophysical environments on human health. In this study, the Leopold matrix was applied to predict the pollution impacts of seven water projects in Karbala city in Iraq based on water quality data collected for the period January to December 2018. The results showed that the impacts of Ca and SO4 in treated water were unacceptable in most cases due to uncontrolled dosage of alum and lime added during water treatment processes. The results also demonstrated that the maximum environmental impact (EIV) for raw water was 51.21 at Al-Hendiya Al-Qadeem water treatment plant (WTP) while that for treated water was 99.97, at Hay Al-Hussein WTP. The obtained impact values of treated water quality parameters in this study occurred due to the use of old techniques in water treatment and demonstrate the need to upgrade these techniques. The Leopold matrix was, however, shown to be good process for sifting out or mitigating the negative effects of such projects on humans and the environment.
Effect of Pavement Foundation Materials on Rigid Pavement Response
Authors: Shaban Alaa M. , Alsabbagh Ahmed , Wtaife Salam , Suksawang Nakin
Published: January 2020

Rigid pavements are increasingly becoming a primary pavement type for highways under heavy traffic loading due to their long service life and less frequent requirements for maintenance compared to flexible pavements. The behaviour of a rigid pavement during service life is affected by several parameters such as applied loading features, pavement properties, environmental effects, and pavement foundation properties, which must be taken into account in the analysis and design of rigid pavements. The pavement foundation consists of base, subbase, and subgrade layers, all of which play substantial roles in the long-term performance of the rigid pavement. With the development of computer capacity, the three-dimensional finite element method (3D-FEM) has become a widely utilized tool for analysis of concrete structures such as pavements as it overcomes the limitations of analytical solutions. The main objective of this research is to evaluate the effects of pavement foundation characteristics on rigid pavement response using EverFE software. The parameters examined in this study included the thickness and properties of each layer of the pavement foundation. The analysis results revealed that, generally, stresses and settlements within rigid pavement are considerably reduced when a stiff or thick foundation is used. The analysis of results also showed that the tension bending stresses in the base layer decreased significantly with increases in the thickness of the base layer. It was also found that the addition of a subbase layer within the pavement foundation produced a significant reduction in the tension bending stresses in pavement and base layers with no in compression stresses in both layers noted.
Experimental Study on Shear Strength Behaviours of the Composite UHPC Steel Girders in Slender web
Authors: Muteb Haitham H. , Hasan Dhafer M.
Published: January 2020

Modern structures require light elements with high stiffness to weight ratios. Composite structures with high-performance material are particularly useful for long spans such as in bridges and large buildings. Conventional concrete is brittle, with very low tensile and high compressive strength; ultra-high performance concrete UHPC can be used to improve the ductility and strength of the deck slab, yet though many researchers have examined the behaviour of UHPC individually, this material requires investigation in conjunction with other variables. A composite structure of steel plate girders and concrete deck is thus examined in the present study, with seven plate girders and three composite girders. Flat web plate girders without stiffeners were investigated to estimate ultimate strength in two parameters, web slenderness, and flange slenderness. In addition, three composite girders were tested with web slenderness ratings 167, 250, and 375. The results show the effects of slenderness on shear strength and the failure accrued due to tension field action, while elastic buckling was seen to contribute to shear strength.
Estimating the viscoelastic properties of local hot-mix asphalt
Authors: Mohamedmeki Mohammed Z
Published: January 2020

The mechanistic empirical method for designing flexible pavement requires determination of the strain that results from applying wheel load. To achieve this, the viscoelastic properties of asphalt concrete is required to be characterised numerically in order to permit simulating such asphalt concrete in finite element modelling for layered systems of flexible pavement. Accordingly, the estimation of the viscoelastic properties of local hot mix asphalt (HMA) was the target of this study. This was achieved using the interconversion process, with the master curve of shear modulus estimated from the master curves of dynamic modulus and phase angle developed within the Hirsch model by substituting the binder dynamic and volumetric properties of local Hot-Mix Asphalt (HMA) into the model. The master curve of shear modulus was constructed with aid of the interconversion process from the creep compliance resulting from Indirect Tensile Tests (ITT) under different testing conditions. The calculated master curve of shear modulus was then used to validate the estimated results. The validation revealed that the estimation method offered good ability to determine the properties required. Numeric values, known as the Prony series, used to characterise asphaltic pavement layers numerically, were established by fitting the normalised master curve of shear modulus. The research results showed that this estimation method is an appropriate way to determine the viscoelastic properties of HMA as opposed to using costly and complex laboratory tests.
Application of Artificial Neural Networks in Predicting Subbase CBR Values Using Soil Indices Data
Authors: Al-Busultan Shakir , Aswed Gafel Kareem , Almuhanna Raid R. A. , Rasheed Sajjad E.
Published: January 2020

Subbase strength characteristics is one of the main inputs of pavement design, and such strength characteristics are normally represented by indices such as resilient modulus, dynamic modulus, and California Bearing Ratio (CBR), with the latter being a widely used index among pavement and geotechnical engineers. This paper examines the capability of Artificial Neural Networks (ANN) to develop a correlation between subbase CBR and primary soil data, which could help with estimating CBR for prediction purposes and with identifying the significance of each index with regard to subbase strength. Data were sampled from different areas in Karbala, Iraq, and a total of 358 subbase samples were used for model training and validation. The results showed that the proposed ANN model could successfully predict the CBR value using soil index data. Additionally, a sensitivity analysis was conducted to determine the importance of each contributing factor, and within the boundaries of the local subbase characteristics, the test results indicated that soluble salts were the most effective factor among soil parameters with an importance percentage of 39.46%, while the Plasticity Index (PI) was the least important factor, with a percentage of 2.06%. Based on the validity and quality of subbase soil tests, using ANN to predict CBR value may offer a suitable replacement for lengthy and expensive laboratory testing based on validated data for materials supplied from Karbala quarries.
Flexural Behaviours of Box Segmental Beams with Internal Tendons Subjected to Repeated and Static Loads
Authors: Wrayosh Waleed A. , Hashim Ahmed H.
Published: January 2020

The main objective of this study is to gain a better understanding of the behaviours of different types of joints when box segmental beams are subjected to bending. Five beams with internal tendons were thus produced and tested: one beam was cast monolithically as a reference beam and four were formed as segmental beams. All beams were produced using Self Compacting-Concrete (SCC) in box sections. Each segmental beam was formed by assembling three precast concrete segments with four post tensioning tendons. The segmental beams had the same general characteristics, but with different types of joints between the segments. Four types of joints were adopted in this study;-dried, epoxied, dried strengthened with carbon fibres and multi-steel shear keyed joints. All beams were tested under two types of loadings, repeated and static. A test of repeated loading was carried out by exposing each specimen to three loading cycles. Each cycle was implemented by subjecting each specimen to up to 40% of the ultimate load then releasing the loads to return the specimen to the non-loading case. The test of static loading was carried out at the same rate of loading as the repeated load test, and all girder specimens were tested up to failure. The loads versus deflections at specified points were recorded for each 5 kN. Cracking, mode of failure and ultimate load values were recorded, along with the concrete surface strains at specified locations for both loadings. The tests results for repeated loading showed that joint type had a clear effect on behaviours in the segmental beams, which had deflection readings ranging from 16 to 61% higher than that of the monolithic (reference) beam, as well as higher tensile strain than seen in the reference beam, by 8 and 67%. Similar effects of joint type were observed under static test. At the first crack loading, the segmental beams had deflections of between 8 and 94% and tensile strains of about 5 to 18% more than the reference beam. The failure modes of the tested beams were all different. Failure of the dry joint occurred in the segment interface, while the failure of each epoxied joint and joint strengthened by carbon fibres developed in the concrete adjacent to the segment interface. The steel shear keys clearly transfer the shear resistance to the concrete parts adjacent of the joints.
Redefining the concept of the 24-hour city and city nightlife for holy cities, with the use of Islamic instructions: A Case study of the holy city of Karbala
Authors: Khorsand Ramin , Alalhesabi Mehran , Kheyroddin Reza
Published: January 2020

The development of the 24-hour city includes the development of infrastructure, and economic, cultural and social planning. The approach taken in most of the western cities has been considered compatible with the lifestyles prevalent in those countries, and has three main parts: people, place, and creativity, and three basic principles: providing a safe city centre for people and their places of leisure, developing the night economy, and improving the city’s image.

The interaction between proponents and opponents of 24-hour cities and their effects on the planning of the cities is also one of the challenges in cities in Islamic countries. Most proponents tend to encourage the creation of new urban places and the introduction of special activities compatible with nightlife. However, some cities already provide opportunities for attendance and activity at all times of day and night without formal organisation, including areas such as Karbala and Mashhad where the focal point is a holy shrine.

Islam has a special view of urban life and lifestyle and therefore defines its own favoured activities, entertainment, residency, and purpose, proposing special times and places for all things. Reviewing the concept of the 24-hour city in light of the Islamic lifestyle using examples of holy cities can thus help redefine the 24-hour city and produce new patterns for it that are more compatible with the needs of Islamic countries.

This research thus tries to answer the following questions using a qualitative method and surveys to develop a case study of Karbala city: What are the connections between an Islamic lifestyle and 24-hour city life? What capacities of the city are lost, based on the current local nightlife? The aim of this study is to begin to redefine the 24-hour city concept to make it compatible with both Islamic culture and local capacity.
Reduction of pollution caused by smoke from brick factories using a water system and reuse of water from brick production
Authors: Abbas Mukhtar Dhajir , Al-Khekany Alaa Mahdi , Al-Yassri Labeeb Saadoon
Published: January 2020

Air pollution is an important contemporary issue and any attempt to mitigate pollution and the environmental impacts is considered significant. In Iraq, dark oil is used as the essential fuel for brick factories. Incomplete burning of this fuel discharges a black smoke, which contains substantial amounts of soot especially at the beginning of any operation. The main objective of this study is to investigate use of a system of spraying water to treat the black smoke that is emitted by brick factories, to reduce the pollution and reuse the industrially-generated black wastewater (IBW). In this study, five samples of water were used, comprising one sample of clean water (control sample) and four samples of IBW, which contained different quantities of soot according to the quantity black oil burned. The burning operation was reproduced by burning0.5,1, 1.5, 2 liters of black oil respectively for the four samples used. The IBW was tested in a laboratory of the environmental authority and it was found to be free from any increased concentration of heavy metals except copper(Cu) and zinc(Zn) elements with a ratio 0.02 to 0.20 mg/l and 2.25 to 2.61 mg/l respectively. The PH was neutral at around 7.3. Further laboratory tests of the IBW showed that it contained sulfates at about 426 to 646 mg/l, nitrates of 12.5 to 31 mg/l, and chlorides at 151 to 178 mg/l. The results showed that reuse of the IBW generated by the brick industry did not affect the compression strength for any samples compared with the control sample (zero soot), which means the adopted system gave a very good results, reducing pollution with the same compressive brick strength.
A Geospatial Approach to Walkability Quantification: Case Study of Main Campus of the University of Kerbala
Authors: Alyasari Haider I , Auda Zaman , Attya Hussein
Published: January 2020

Walkability is an urban quality indicator that is gaining increased attention because of its relationship to sustainability. Walkability refers to the set of incentives an urban space offers to encourage walking. More incentives mean higher walkability, hence more sustainable urban planning. This paper presents a geospatial approach to quantify the walkability of an urban space, based on physical indicators that can be layered in a GIS system. Preliminary results show good performance of the approach on the global level. However, further research is recommended to enhance performance at the local level.
Site Investigation of Alauqaiser Historic Church Using Photogrammetric Reconstruction
Authors: Naji Haider , Al-Taweel Maryam D. , Fadhil Anwar
Published: January 2020

Alauqaiser Church is one of the Christian heritage sites that are mentioned extensively in historical literature. The site is described to be in the desert to the south west f Karbala, Iraq. The site was excavated by the Iraqi government to reveal most of the church building which was covered by soil for long time. However, it is believed that there could a human settlement around the church which is not investigated or determined physically on the ground. This paper aims to investigate the possibility of the existence of any settlement or development around the site and stimulate further research about this important fact. Photogrammetric reconstruction was used to prepare engineering drawings and digital three-dimensional models of the site. Pictures were captured using off-the-shelf small drone which successfully provided enough level of details to prepare precise orthophoto and digital elevation model of the site.

Results of the site’s orthophoto and digital elevation model showed that there are clear footprints of physical development around the church.
Investigating the effect of polypropylene fibre on mortar mechanical properties with the aid of microwave curing
Authors: Abed Alameer Sara Alaa , Mohammed Ali Mohammed Riyadh , Majeed Ridha Hameed. , Alyhya Wajde Shober
Published: January 2020

In recent times, there has been increased interest in using various types of fibres in the cement-based materials industry. This work thus aims to investigate the possibility of improving the mechanical properties of mortar samples by using available and cheap polypropylene fibre with the aid of a microwave curing technique. For this purpose, 5×5×5 cm cubes of mortar containing different percentages and lengths of polypropylene fibres were cast and then subjected to various ranges of curing time under microwaves. Compressive strength, direct tensile strength, and density tests were conducted on reference mortar (specimens without fibres) and mortar reinforced with polypropylene fibre specimens at various ages (3, 7, and 28 days) of curing. The results showed a marginal decrease in the compressive strength against an increase in the direct tensile strength as fibre content increased. All mixes showed acceptable values for density against the reference mixes.
The Influence of Curing Methods on Marshall Stability and Flow
Authors: Fadhil Talal H. , Ibrahim Rahel Khalid , Fathullah Hardi Saadullah
Published: January 2020

The Marshall Mix design is one of the most widely used methods for designing and evaluating hot asphalt mixes globally, and the main Marshall Test focuses are stability and flow. Two standard curing methods are normally followed to elevate the temperature of testing samples; these involve immersing the samples in 60°C water or placing the samples in an oven at 60°C. These standard curing methods may not simulate the actual state of heating of asphalt pavement in the field, however. In this research, a new curing method that includes insulating the samples before immersion in hot water is thus introduced and compared with the two standard curing methods. During immersion, the water temperature is increased to 60°C and the core temperature of the insulated samples determined. Three sets of Marshall Samples were prepared and cured using the outlined methods; each set consisted of 18 specimens of 101 mm diameter and 63.5 mm height. All specimens were tested using the Marshall Test for stability, flow, and Marshall Stiffness. The set mean results showed that the oven cured samples demonstrated the highest stability values, followed by the standard water cured samples, while the insulated samples exhibited the lowest stability values. The oven cured samples also exhibited higher Marshall Stiffness Index (MSI) values than the other curing methods. However, one-way ANOVA (single factor) testing demonstrated that these differences were not statistically significant.
Tool path generation for a car rear door die: UMO versus rest milling tool paths
Authors: Alwan Ali K. , Hamdan Wissam K.
Published: January 2020

Tool path generation for sculptured surfaces that contain many concave and convex features involves gouging and undercut problems. Past research has paid little attention to tool path generation for hard materials, which require careful and precise planning. In this paper, a comparison is made between traditional unit machining operation (UMO) and rest milling-based tool paths for the various machining steps (roughing, semi-finishing and finishing) of a car’s rear door, designed by NURBS surfaces. The experimental work involves the machining of two dies in a 3-axis CNC machine. Each die comprises two parts: punch (convex) and die (concave). Various tool path patterns (contour, zig-zag, zig, concentric zig-zag) are generated and compared via NX8 software. The results show a great saving of time and less tool consumption by using a rest milling technique over UMO techniques.
Water solar distiller productivity enhancement using solar collector and phase change material (PCM)
Authors: Shareef Abbas Sahi , Rashid Farhan Lafta , Alwan Hasan Fathi
Published: January 2020

This paper examines the use of a solar still associated with a solar collector, and phase change materials, in improving productivity in solar distillation. We contrasted productivity from a solar still associated with a solar collector both with and without PCMs, and explored relevant issues around design and installation. Experiments were conducted at an east–west orientation in Karbala at the end of October and beginning of November. Polyvinyl pyrrolidone (PVP K-30), polyethylene glycol (PEG 6000) and carboxymethyl cellulose sodium salt (CMC ), were used for their chemical properties as latent heat energy storage. The hourly output rose little where the solar distillation was coupled with solar collector but without LHTESS, through sunny days. There was an increase of about 30%–50% in freshwater output for LHTESS than was the case without. As daylight progressed the pure water created by the solar still increased. A solar still with solar collector for LHTESS is found to be increased according to the type of additive used. Water temperature was measured in a specified period. We studied the use of a solar still associated with solar collector both with and without PCM as thermal storage. The system run time was increased with the addition of PCM. System productivity and system efficiency also increased, by about 120 % and 40% respectively.
Study of the Effects of Welding Process on the Microstructure of Worn Carbon Steel Shaft
Authors: Sadeq Basim Raheem , Sahib Basim Salih , Alher Murtadua
Published: January 2020

This paper presents a new procedure to repair a worn, low carbon steel shaft by use of discontinuous arc welding, and studies the effect of the proposed methodology on the microstructure of the welding area. The aim of the proposed methodology is to repair locally the rotary shafts of mechanical equipment, which are usually damaged at the supporting zone. The compensating method is used to repair the damaged area by adding a thin layer of metal to compensate for the shortage in diameter as a result of erosion. The repair should be carried out without exposing to rising temperature, which is the main cause of stress concentrations and initiation of fatigue cracks. The results were obtained by microscopic analysis of the welded area and include mechanical properties for the obtained samples. The repaired area contains soft crystals and an increase in hardness above 41%. This indicates that the wear resistance has been improved, while preserving the tension strength as it was before repair.
Providing A Long-term Protection for NCM811 Cathode Material by Al2O3 Coating Layer
Authors: Wang Jing , Yuan Qiang , Wang Ran , Tan Guoqiang , Su Yuefeng , Li Danhua , Wu Feng
Published: January 2020

The degradation of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode material is successfully suppressed via a facile Al2O3 coating method. The coated Al2O3 layer on the electrode surface is inactive and amorphous, it does not react with the electrolyte and could provide a long-term protection on the electrode during cycling. The electrochemical performance of the modified NCM811 was improved dramatically both at room and elevated temperature. The capacity retention of pristine NCM811 was enhanced from 81.8% to 91.7% when the coating amount reached to 2 wt% at 25°C and much increased from 68.5% to 87.7% at 55°C. Such excellent high temperature performance clearly confirmed the effect of Al2O3 on the structure stability of electrode, it successfully built a favorable protection of the bulk NCM811 from direct contact with electrolyte and suppressed the undesired side reactions.
Research Progress on High-temperature Oxidation of Austenitic Stainless Steel for Ultra-superCritical Boilers
Authors: Song Tao , Wang Zhiwu
Published: January 2020

In this paper, four typical austenitic heat-resistant steels (TP304H steel, TP347H steel, Super304H steel and HR3C steel) are taken as examples to review the research progress of high-temperature oxidation of austenitic stainless steel for ultra-supercritical unit boilers, and the mechanism and protective measures of high-temperature oxidation of austenitic stainless steel are discussed, so as to provide references for material improvement and safe use of unit boilers.
A Refined Model for Predicting the 31-Coupling Effect of Piezoelectric Structural Fiber Composites
Authors: Xu Yaoling , Zheng Lishuang
Published: January 2020

A refined model is proposed to predict the 31-coupling effect of a piezoelectric structural fiber (PSF) and PSF composites. The PSF model consists of a piezoelectric shell, inner and outer electrode layers, and a piezoelectric inactive core fiber. The inner and outer electrodes provide a radial electric field passing through the piezoelectric shell, which leads to the axial deformation of the piezoelectric shell, the piezoelectric inactive core fiber provides the mechanical support to the brittle piezoelectric shell. Analytical expressions of the effective piezoelectric coefficient d
31 of the single PSF and the PSF composites are derived, the influences of aspect ratio of the piezoelectric shell, thickness of the electrode layer and PSF volume fraction, on the effective piezoelectric coefficient d
31 are demonstrated. The numerical results show that the model without electrode layers may lead to a significant error.
Study on Hot Deformation Behavior and Constitutive Model of TNTZ Alloy
Authors: Cheng Jing , Wang Kelu , Li Xin , Liu Jianjun
Published: January 2020

The isothermal constant strain rate compression experiment of Ti-29Nb-13Ta-4.6Zr (TNTZ) alloy with deformation temperature of 700∼900°C and strain rate of 0.001∼1s-1 was carried out by Gleeble-3500 thermal simulator. The high temperature deformation behavior of the alloy was discussed and the thermal deformation activation energy was calculated. The hyperbolic sinusoidal constitutive model of TNTZ alloy was constructed. The results show that the flow stress of the alloy tends to be steady at high temperature and low strain rate. The constitutive model established by the Arrhenius model and modified by Zener-Hollomon parameter, which its correlation coefficient R and the average relative error E is 0.971 and 5.92%. The results predicted value for high temperature deformation behavior and agrees well with the experimental value of the alloy.
Effects of Cooling Conditions on Surface Integrity in Turning of TC4 Alloy
Authors: Li Jianming , Li Taoyuan , Wang Xiangyu , Qiao Yang , Guo Peiquan
Published: January 2020

Machined induced surface integrity of titanium alloy is of great importance due to its strong correlation with the functional performance and service life. In this paper, the effects of different cooling conditions on the surface integrity of TC4 alloy were studied experimentally. The results showed that the values of surface roughness and surface residual stress under cryogenic condition were lower than those under dry condition and emulsion cooling condition with the same cutting parameters, while the influence of cooling condition on the microhardness of the machined surface is not obvious. Cryogenic cutting is an effective way to machine titanium alloy.
Hybrids of Nickel-histidine Functionalized Graphene Quantum Dots: Fabrication and Non-enzymatic Glucose Sensing
Authors: Yang Yongqiang , Chen Wei , Wang Qinsheng , Wang Qun
Published: January 2020

In this work, a method of in-situ recombination of Ni2+ with histidine functionalized graphene quantum dots (His-GQDs) was constructed a three-dimensional network porous structure. The collected precipitate complex precursor was oxidized and the NiO-His-GODs were obtained. The NiO-His-GQDs compound was subjected to high-temperature thermal reduction by inert gas to form Ni-His-GQDs. On the one hand, the intimate contact between Ni nanoparticles and His-GQD greatly shortens the gap between the two complexes, resulting in faster electron migration speed; On the other hand, the conductive (Ni)/semiconductor (His-GQDs) catalytic interface can produce Stokes diode-like structures, accelerate the migration rate of holes carriers in the semiconductor, and exhibit good electrocatalytic activity. A Ni-His-GQDs modified electrode as non-enzymatic glucose electrochemical sensor was shown good electrocatalytic activity and anti-interference property. The concentration of glucose was detected by amperometric analysis, and showed a good linear relation in the concentration range of 5.0 × 10-6∼2.0 × 10-3 M. The detection limit (S/N = 3) is 1.7 × 10−6 M. In addition, interference of sodium chloride (NaCl), uric acid (UA), dopamine (DA) and ascorbic acid (AA) was less than 5.0 % in the same conditions indicating that the hybrids modified electrode sensor could be used for the sensitive and selective detection of glucose.
Progress and Challenges Related to Thermal Fatigue Research of Super-hard Cutting Tools
Authors: Guo Caifen , Dong Zhi
Published: January 2020

A large number of super-hard tools literature has been studied, most of which aimed at tool wear patterns and mechanisms. Researches on thermal lord affecting tools wear are carried out insufficiently and achievements about thermal cracks initiation, propagation are little reported. As existing of elevated temperature and intense heat during cutting processes, super-hard cutting tools thermal fatigue problems are obliged to be faced and some fundamental and unresolved issues need to be answered.
Uncertainty Analysis for the Estimated Hydraulic Conductivity from the Reduced Duration Pumping Test
Authors: Zhang Ying , Lu Chengpeng , Zeng Rui , Jiang Liyong , Wei Lei
Published: January 2020

Use of a homogeneous aquifer method to represent a heterogeneous aquifer for parameter estimation will inevitably result in uncertainties in the estimated parameter values. The objective of this paper is to evaluate the impacts of the reduced duration of the pumping test on the estimated hydraulic conductivity using the observations from pumping tests. Firstly, a heterogeneous hydraulic conductivity K field was generated using the Monte Carlo method. A MODFLOW groundwater flow model was then constructed to perform numerical pumping tests. The K value was estimated by the inverse method based on the Theis solution for an unconfined aquifer. The K fields were generated based on the hydraulic conductivity data sets collected for a karst aquifer in southwest of China. The effective hydraulic conductivity (Ke) was calculated to represent the hydraulic conductivity of a heterogeneous aquifer. For a single test in a heterogeneous aquifer, while the duration of the test is less than a critical value, the reduced duration will lead to the big uncertainty of the estimated hydraulic conductivity. However, Ke can achieve a relative stable value while the number of reduced duration tests is big enough to eliminate the impacts of the uncertainty of the separate K values.
A Novel BP Neural Network with Wavelet Transform Inputs for Air Quality Index Prediction
Authors: Fang Zheng , Zhang Lei , Huang Yakun
Published: January 2020

Air quality index prediction research is of great significance to people’s life. Various prediction methods are used to pursue its accurate prediction. A novel BP neural network with wavelet transform inputs for air quality index prediction is proposed in this paper. The proposed method introduces wavelet transform in the front of the neural network. It decomposes the original time series signal into a linear superposition of the main signal and some noise signals. After establishing the predictive BP neural network for each decomposed signal, the air quality index is restored based on the linear additivity of wavelet decomposition. The simulation experiments show that the prediction accuracy of proposed method is high. The relative error of long-term prediction for 50 consecutive days is only 4.3994% for Xuzhou City’s air quality index. The research work provides a useful reference for air quality index prediction.
FAHP on the Development of Exhibition Ecological Education
Authors: Yang Lin
Published: January 2020

Based on the research findings of some experts, this article tries to construct the index system of the sustainable development of exhibition ecological education and the assessment model with the utilization of FAHP. In the meantime, it conducts the fuzzy Comprehensive assessment with the case study of Jinhua Polytechnic.