bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the influence of aromatic hydrocarbons on the process of tar oxidation
Authors: Ahmed Adnan Al-Razoqi , Alexandra Shrubok , Alfarge Dheiaa K. , Veronika Zholnerkevich , Julia Harashchuk , Dmitry Kuziomkin
Published: August 2024

This study examines the impact of polycyclic aromatic hydrocarbons on the oxidation of petroleum tar. An aromatic hydrocarbon concentrates isolated from extracts of selective oil purification using the polar industrial solvent N-methylpyrrolidone was employed as an additive to tar. The relationship between the softening temperature of oxidized bitumen and both the duration of oxidation and the properties of the initial raw material mixture was investigated. It has been established that the introduction of 10 wt.% aromatic additive will increase the oxidation rate by 6 °C/h. The conditions for producing road bitumen from the proposed raw material compositions were identified. The influence of polycyclic aromatic hydrocarbon concentrate on the qualitative characteristics of bitumen during the tar oxidation process was determined. Aromatic additive is similar to a plasticizer, and reduces the softening temperature of bitumen by 9 °C. But the combined oxidation of tar with an aromatic additive and a catalyst makes it possible to obtain bitumen with a softening point of 44 °C and a penetration of 80 x0.1 mm, which corresponds to the grade of bitumen 70/100. Analysis of the group composition of oxidized bitumen revealed that the aromatic additive facilitates the intensification of the tar oxidation process.
Displacement of rocks and parameters of the trough of displacement
Authors: Asanbekovna Kadyralieva Gulzat , Torokulovich Djakupbekov Belek , Usenbekovna Isagalieva Seiilkan , Ataibekovich Aitkuliev Nurlan
Published: August 2024

This article examines the relevance of issues related to the movement of rocks and the determination of the parameters of the zone of propagation of the slide, since to this day, there are a number of unresolved problems in the field of its practical application. Returning to the origins of the formation of mining sciences and the field of their study, it can be noted that these issues have been moving from one group to another for a long time, but still related to the tasks of surveying. However, studying this issue gives a clear understanding that it should be solved in a wider range, involving knowledge in such fields as geology, physics and mechanics of rocks, surveying, mining science, as well as the necessary knowledge in the field of managing the state of the massif and its stress-strain state. The discipline that most fully embraces all of the above sciences for studying the processes of rock movement is geomechanics, from which side attempts were made to study it.
Unconventional Intersection Design to reduce The Delay Time for Bab Al Mashhad Intersection in Hilla City
Authors: Raty Ancer Kareem , Obaid Hayder Abbas
Published: August 2024

The study aims to evaluate and improve traffic movements for an intersection in Bab al-Mashhad in Hilla City, the improvement for this intersection is done by changing the intersection from a conventional model to an unconventional model. The video techniques were utilized to gather the traffic data. The traffic information was collected from the video by using the event program and arrangement by Excel sheet, the VISSUM software was used for the simulation process. This simulation shows the level of service before improvement (F) and after improvement (C) and emission co decreased with 64% so this is lead to activate the sustainability principles in the intersection. The results refer to the traffic volume had big effect on intersection sustainability classification The results refer to a good acceptance of using the unconventional intersection to improve this traffic movement intersection.
The Impact of Climate Change on Water Quality and Consumption in the Tigris River Basin (Mosul-Baghdad)
Authors: Saleh Rana Abdel Qader , Oleiwi Alyaa Shakir , Lateef Zahraa Qadra
Published: August 2024

Iraq is one of a riparian country into the basin of Tigris River with (Turkey, Syria, and Iran). The region is currently facing water shortage problems due to climatic changes the rise of the demand on water. The meteorological data was used to estimate the water surplus and water deficit for the period (1990-2021), while the hydrological data was used to show the variation of the flow during the years due to climatic change on the Tigris River basin (2005-2021), and applying the SCS-CN method to estimate the surface runoff. The impact of climate change was estimated by calculating its effect on the physochemical characteristics in the river basin for the period (from January to December\2021) and compared it with standards specifications, in addition to comparing of amount of the water consumption in the Tigris River during the period (2017-2021). The results show a high ratio of water deficit in the downstream of the Tigris River basin due to decreasing the precipitation ratio in these areas. The Rainfall-Runoff-Depth was simulated using the SCS-CN method. The water quality parameters of Tigris River were within the standards of drinking water, except of TDS values at Tharthar-Tigris canal and Baghdad which exceeded the permissible limits. The results show an impact of climatic change on a Tigris River are different but it’s more effects in urban areas due to water consumption of the Tigris River.
Promoting Sustainability in Housing Sector Using Eco-Friendly Materials
Authors: Abbas Maher K. , Dhuha A. H. , Tabark M. A.
Published: August 2024

The significance of sustainability in the housing sector is essentially demanded nowadays, driven by the global emphasis on sustainable development and urgent environmental challenges. It emphasizes the need for innovative strategies to enhance resource efficiency and mitigate negative environmental impacts during construction. Achieving sustainability requires incorporating environmental design principles and eco-friendly building materials, necessitating comprehensive considerations in urban planning and design. This involves promoting sustainable public transportation, communities, facilities, and green spaces. The aim of this study is to convert non-sustainable houses into sustainable ones; aiming to support Iraqis seeking housing that meets international sustainability standards. It also aims to assist the Iraqi government in fulfilling its commitments under the Paris Agreement and improve the quality of life for Karbala’s residents. The primary objective is to design a house that balances environmental, economic, and social factors, adhering to international environmental standards and sustainable development requirements. This involves utilizing sustainable techniques like renewable energy and eco-friendly materials. The project adopts a comprehensive approach that accounts for the various dimensions of sustainability during the design process.
Impact of Using Subsurface Water Retention Technology on Improving Water Use Efficiency of Furrow Irrigation System
Authors: Sadoon Mushab Fatima , Khairi Ibrahim Ali
Published: August 2024

Evaluation was carried out on the existing furrow irrigation system located in an open agricultural field within Hor Rajabh Township, south of Baghdad, Iraq (latitude: 33°09’ N, longitude: 44°24’ E). Two plots were chosen for comparison: treatment plot T1, which used subsurface water retention technology (SWRT) with a furrow irrigation system. While the treatment plot T2 was done by using a furrow irrigation procedure without SWRT. A comparison between the two treatment plots was carried out to study the efficiency of the applied water on crop yield. In terms of agricultural productivity and water use efficiency, plot T1 outperformed plot T2, according to the study’s final findings. Compared with plot T2, the rate of increase in the efficiency of water and crop yield were found to be 44.9% and 14.2%, respectively. Additionally, compared to plot T1, the rate of increase in the applied water in plot T2 was 26.8%. The efficiency of plot T1 is attributed to the usage of SWRT membranes beneath the plant’s root zone, which helped conserve water and nutrients, which affected crop yield and water consumption.
Occurrence of Micro-Plastics in Tigris River Water in Middle of Iraq
Authors: Safaa Al-Azzawi Ahmed , Yaseen Al-Kindi Ghayda , Al Rifaie Jawad K
Published: August 2024

Microplastics, which are emerging pollutants in the environmental world, have become a source of concern for researchers and the public by virtue of the increasing use of plastic and mismanagement of plastic waste. Currently, research focuses on marine environments, with less attention to freshwater environments, especially urban rivers. In this study, 11 samples were taken from surface water along the Tigris River in the city of Baghdad and from the Kut Dam. The process of chemical digestion using H2O2 (30%) was used to digest natural organic materials, separation by density to get rid of unwanted materials, and then examination under an optical microscope and FTIR. The abundance of plastic materials ranged from 27to74 particles/sample size. Polypropylene, polyethylene and polystyrene were common types of microplastics as they represented (66.92%) of the samples. Fibers and fragments were the dominant microplastic forms in all samples. White color is the dominant characteristic of all samples. It has been shown that hydrodynamic conditions and the locations of urban cities and industrial facilities affect the concentrations of microplastics. The study’s results at S9, S10, and S11 show that microplastics are accumulating in the dam, indicating that the dam might act as a sink for microplastics.
Meteorological Drought Analysis in Iraq using SPI and Theory of Runs for the Period 1980-2022
Authors: Ismael Yaseen M. , Awchi Taymoor A.
Published: August 2024

Iraq, like many other countries in the world, suffers from alternating periods of drought. The aim of this paper is to analyze the meteorological drought in Iraq for the time period 1980-2022, at 27 meteorological stations spread throughout Iraq. Monthly data for precipitation values were collected from the Iraqi Meteorological and Seismological Organization (IMOS). The monthly time series contained missing data that were compensated by the normal ratio (NR) and the multiple linear regression (MLR) methods. To compare the two methods and evaluate the results of filling for missing data, statistical tests were used. The homogeneity test, the Mann-Kendall test, and the consistency test were used to determine the accuracy of rainfall data records and to know the trend of climate data and how its homogeneity. To estimate drought values, the Standard Precipitation Index (SPI) was used for 12-month time scale, and the theory of runs was used to analyze the characteristics of meteorological drought, such as its duration, intensity, and amount of rain deficit. The results of the statistical tests showed that the (NR) method is more accurate and reliable and gives the best results with less errors after examining it with six statistical indicators than the (MLR) method. The results of the homogeneity tests showed that all stations were consistent and homogeneous, except for the Haditha station, which failed two tests and its data was corrected using double mass curve method, so it became homogeneous. The results of the Mann-Kendall test showed that all stations recorded a decrease in average rainfall values during the study period, except for the stations in Baghdad, Erbil, and Salahaddin, and it was most severe in the northern stations such as Sulaymaniyah, Khanaqin, Kirkuk, Mosul, Zakho, and Tal-Afar. The SPI results showed that Iraq faced repeated and successive periods of drought, which covered 45% of the study area for the years (1998-2001), 41% for the years (2008-2011), and 14% for the years (2015-2017), and were most severe in the northern stations where drought severity reached the maximum at Salahaddin station which recorded a rainfall deficit of 396.95 mm/year. The Amara and Samawa stations suffered from repeated short and long-term drought periods 18 times during the study period.
Water Scarcity Effect on Kirkuk irrigation project
Authors: Salah Yaseen Riyam , Ridha Faris Mariwan
Published: August 2024

The Kirkuk irrigation project is very importance for the Kirkuk Governorate. The governorate has been significantly affected due to the water scarcity in Iraq. The shortage of the water can be attributed to various factors. The most important one related to influence of recent climatic changes on the water strategies implemented by neighboring nations sharing borders with Iraq. Moreover, Iraq is facing several challenges in the mismanagement of its water resources. The rise in population has led to a higher demand for water. This study examines various stages of the Kirkuk irrigation project, including the main channels and the feeding channel. Also, this study analyses the dams and projects established by Iran they have Indirect effect on project by cutting the feeding tributaries of dam which Kirkuk irrigation project mainly depended on it. Furthermore, this study explores the consequences of water scarcity on the agricultural output of Kirkuk proven. At the normal years of the project the annual discharge of the Kirkuk irrigation project was higher than they are currently. In 1996, the annual discharge for the Kirkuk irrigation project was 104.5 m3/second, and in 2023, t decreased to 30 m3/second. This reduction forced the farmers to excavate wells for irrigation purposes, and by the year 2023, the total number of wells in the Kirkuk had reached 291,480. the study explores the consequences of water scarcity on the agricultural output of Kirkuk project. Drought and water scarcity have decreased the annual share of individual water share, in 2003 the amount of water per capita was 2393.55 m3/year and decreased in 2021 until it became 758.42 m3/year.
Assessment of raw and produced water quality at Al-Doura water treatment plant
Authors: Mohammed Raheem Hawraa , Rashid Al-Juhaishi Mohammed
Published: August 2024

The population growth rate has increased rapidly in recent years so there is an obligation to evaluate the productivity of produced water (PW) by investigating the operation of the Water treatment plant (WTP). WTP’s primary goal is to remove and destroy harmful organisms from contaminated water to make it safe for human consumption. The quality of PW depends on the performance of WTP. This study aims to assess the removal efficiency of Al-Doura WTP in Baghdad City/Iraq and ensure that the drinking water quality meets the drinking water standards. Twenty-two water quality parameters are analysed over four years (from January 2020 to December 2023). The samples of raw water are collected from the Tigris River at the intake of the WTP, while the PW samples are collected at the final stage where the water undergoes treatment before being distributed to the consumers through the network. The measured parameters are Temperature, Turbidity, Alkalinity as CaCO3, Total Hardness as CaCO3, Calcium as Ca, Chloride as Cl, Magnesium as Mg, pH, Colour, Electrical Conductivity EC, Free chlorine (Residual chlorine), Sulphate as SO4, Total dissolved solids, Suspended solids, Iron as Fe, Fluoride as F, Aluminium as AL, Nitrite as NO2, Nitrate as NO3, Ammonia as NH3, Silica as Sio2, and Orthophosphate as PO4. In this study, special focus is concerned with some of these water quality parameters, temperature, pH, electrical conductivity EC, and Turbidity. The analysis is sub-categorized into winter and summer seasons. The SPSS software is used to analyse the data. The results indicate that there is no significant difference between the temperature of raw water and that of the produced water, and the pH values indicate slight alkalinity for raw water in both seasons. Electrical conductivity Ec values for both raw and produced water are found always greater in winter than in summer. The turbidity is found to satisfy the permissible limits for both the Iraqi and World Health Organisation standards (Turbidity < 5 NTU). The drinking water produced from the Al-Doura water treatment plant is found to be within Iraqi and WHO standards, The high difference in turbidity concentration before and after treatment and the removal efficiency excellent value of close to 98% indicates that the plant is highly effective and reflects the effective process of Al-Doura WTP in removing particulate matter and improving water clarity. The Pearson, correlation analysis results indicate a strong (positive, and negative) correlation in the relationship among some parameters reported in this article.
A Comparative Study for the Mesoscale Models of Concrete
Authors: Hussein Ali Hasan , Zain-alabdeen Wurood R. , Al-Rumaithi Ayad
Published: August 2024

This paper provides an overview of mesoscale models used to simulate concrete behavior. A comparative analysis was carried out using mesoscale models with two dimensions. The impact of material type on three tests: the indirect tensile splitting test, the three-point bending test, and the direct tensile test was examined in the study. Additionally, a comparison is made between the findings obtained with and without the application of ITZ and the analysis results obtained from the direct tensile test. The results showed that the fixed crack model had higher stiffness than isotropic damage model in both direct tensile test, and three-point bending test. In indirect tensile splitting test, only fixed crack model gave meaningful results. The models with ITZ had most of the cracks in ITZ rather than in the mortar.
Impact Assessment of Mixing Conditions on Rubberized Asphalt Binder
Authors: Mohammed Humam H. , Joni Hasan H.
Published: August 2024

The objective of this study was to enhance the efficiency of the approach employed for preparing asphalt binders modified with waste rubber nanomaterial. A high-shear mixer has been utilized, with revaluation rates of 3000, 4000, 5000, and 6000 rpm. In addition, a mixing time of 30 minutes was employed. Four different waste rubber nanomaterial dosages were used: 0.5%, 1%, 1.5 %, and 2% by weight of asphalt cement, respectively. The asphalt binder was heated to 140 °C. The characteristics of the modified asphalt binder, including penetration grade, softening point temperature, temperature sensitivity, rotational viscosity, and ductility, were analyzed. The study demonstrated that incorporating waste rubber nanomaterial as a modifier improved the physical characteristics of the asphalt binder. Overall, the study revealed decreased penetration and increased softening point temperature and viscosity values. Additionally, the temperature sensitivity was enhanced. In addition, high shear mixing proved to be more efficient in achieving a thorough dispersion of waste rubber nanomaterial particles within the asphalt binder, resulting in a uniform composite binder. The tested samples demonstrated that adding a dosage of 1 % waste rubber nanomaterial enhanced the physical characteristics of asphalt, making it more suitable for the construction of highway pavements in hot weather conditions.
Combined effect of fiber and degree of stabilization on the early age behavior of cement bound granular mixtures
Authors: Dulaimi Omar I. , Hilal Farhan Ahmed
Published: August 2024

An investigation has been undertaken to study the effect of fiber-reinforcement and different degrees of stabilization on the early age mechanical behavior of cement bound granular mixtures intended to be used as a base layer within pavement structure. Waste plastic fibers (WPF) recycled from soft drink bottles were used at 1% by the mass of aggregate to reinforce cemented mixtures. To stabilize different mixtures, cement content of 3%, 5%, and 7% by the mass of aggregate and by the weight of aggregate and fiber were used for conventional and fiber-reinforced cement bound granular mixture (CCBGM& FRCBGM), respectively. The examined properties include unconfined compressive strength (UCS), indirect tensile strength (ITS), bulk density, and ultrasonic pulse velocity (UPV). The results showed a significant improvement in UCS and ITS as the cement amount increased for both types of mixtures. Incorporating PET fibers at cement content of 5% and 7% resulted in a noticeable improvement of ITS compared to the conventional mixtures while a marginal enhancement in the UCS occurred due to fiber-reinforcement. Both bulk density and UPV were increased as cement content increased, while both were decreased due to the inclusion of waste plastic fibers (WPF). Hence, utilizing waste plastic fiber has a positive and promising effect on the pavement structure from sustainability, integrity, and economic points of view.
The Mechanical Characteristics of Enhanced Bendable Concrete By Polyvinyl Alcohol Fibers
Authors: Mohammed Zaki Al-Masraf Harith , Salih Al-Attar Tariq , Jawad Frayyeh Qais
Published: August 2024

Engineered Cementitious Composites (ECC), which are alternatively referred to as Bendable Concrete, is a class of Ultra-ductile cementitious composites characterized by their remarkable ductility and polyvinyl alcohol fiber (PVA) fiber reinforcing. These composites are designed to regulate cracks width effectively. This study investigates the influence of matrix flowability, fiber mixing technique, and curing conditions on the mechanical characteristics of Bendable Concrete utilizing high-tenacity (PVA) fibers. This study examined the compressive strength of Bendable concrete, which ranged from 60 to 70 MPa, with a strain exceeding 3%. To regulate the flowability of the matrix, high range water reducing admixture (HRWRA) was added to a matrix with a weight ratio of silica fume was 10% by weight of cement, a weight ratio of water to cementitious material of 0.3, also polyvinyl alcohol acetate solution (PVAS). The primary parameter under investigation in this study is the changing volume fraction dose of (PVA) fiber, while the remaining materials of the combination were held constant. Four different (PVA) fiber percentages (0.5, 1.0, 1.5, and 2.0)% were adopted by volume of cement. Three (cubes, cylinders, and prisms) were fabricated and cast from each mixture and tested at the ages (7, 28, and 90) days for investigated (compressive, splitting tensile, and Modulus of Rupture) strength, respectively. The results of the tests demonstrated that the proportion of fiber substantially affects the strengths, where both the Compressive strength and Splitting tensile strength were increased with the increment of fiber content until 1% of (PVA) fiber . In comparison, the higher Modulus of Rupture was abtained at 2% (PVA) fiber.
Experimental Investigation of the Behavior of SlFCON Column under Eccentric Monotonic Load
Authors: Abdulabbas Ali I. , Alwash Nameer A.
Published: August 2024

This research delves into the performance of Slurry Infiltrated Fibrous Concrete (SIFCON) columns when subjected to eccentric monotonic loading, through the examination of twenty columns until their point of failure. The research addresses gaps in existing literature by examining the effects of various parameters, including fiber type, volume fraction, and eccentricity ratio, on SIFCON column performance. Results reveal significant correlations between the studied parameters and the structural behavior of SIFCON columns. The investigation shows how the ultimate load affect by the eccentricity ratio, for instance, the hook end steel fiber with a volume fraction of 6%, where the ultimate load decreased by a factor of 0.25 when the eccentricity ratio changed from 0.1 to 0.5. Furthermore, increasing the volume fraction of steel fibers significantly enhances the energy absorption of SIFCON columns. For instance, with the hook-end steel fiber and an eccentricity ratio of 0.3, the energy absorption increased by a factor of 2.76 when the volume fraction of steel fiber changed from 4% to 9%. The type of fibers used plays a pivotal role in the material behavior of SIFCON, with the straight micro fiber exhibiting an ultimate load 2.17 times greater than flat crimped steel fiber types when the volume fraction was 9% and the eccentricity ratio was 0.3. Finally, based on the experimental results, an interaction diagram has been established for three types of SIFCON: straight micro steel fiber with a volume fraction of 12%, hook end steel fiber with volume fractions of 6% and 4%.
Evaluation of Safety and Operational Efficiency using Structural Health Monitoring Method
Authors: Flaih Athab Hassan , Yousif Aziz Hussein
Published: August 2024

The challenges posed by uncertainty in design and use and the absence of traffic laws and regulations. The researchers conducted an assessment of operational efficiency using the structural health monitoring system. The Samawahh North Bridge, located in the city of Samawahh in southern Iraq, was chosen as a case study to evaluate its construction performance and its compliance with the approved requirements and specifications for structural safety and service validity. Service and safety assessment was carried out through practical tests and numerical simulations using CSI Bridge V.24 software. Variable Differential Transformer (LVDT) displacement sensors were installed and connected to the data acquisition device, followed by a static load test performed on the bridge. When extracting the displacement and distribution coefficient (DF) values, it was found that all these indicators were approximately 80 and 90% lower than the AASHTO specifications approved steel span and concrete span respectively, and no anomalies were detected. This study contributes to promoting economic growth and ensuring increased safety. The methodology included static load tests and frequent updating of the modified finite element model based on experimental data. Therefore, it is recommended to continue to use and rely on the updated FEM in subsequent bridge analyses to effectively evaluate performance and ensure structural integrity.
Evaluating the Structural Integrity of Cellular Steel Beams with Web Enhancements
Authors: AlShamaa Mushriq F. K. , Ghaddar Maha G. , Jebur Maher M. , Al-Rumaithi Ayad , Hussain Alshimmeri Ahmad J. , Karkush Mahdi
Published: August 2024

This study investigates the analytical approach of web reinforcement techniques, including high-strength concrete and laced reinforcement, to enrich improvement for the structural behavior of these beams. The analysis compares an unmodified cellular beam (LB1) with a web-reinforced beam (LB2), including the improvements in load-carrying capacity. The study considers the effects of reinforcement on critical design limit states, such as flexural strength, Vierendeel bending, web post-buckling, and shear resistance. The outcomes reveal significant enhancements in LB2’s structural behavior, with over a 100% increase in flexural strength and local axial force capacity and a 165% increase in web post-buckling strength. This research validates the effectiveness of web reinforcement techniques in concentrating on the limitations of cellular beams and maximizing their potential in structural applications.
Characterisation of T1 (Al2CuLi) Precipitates in Conventional (2099-T83) and Laser Additive Manufactured (PBF-LB/M, DED-LB/M) Microstructures
Authors: Adjei-Kyeremeh F , Akuata C K , Bansal N , Zischke S , Raffeis I , Polaczek A B
Published: August 2024

The high strength and lightweight benefits of Al-Cu-Li alloys make them attractive for aerospace applications. The major strength contributing phase is the T1(Al2CuLi) phase. Although extensive reporting is known on its nucleation behaviour and structure in conventional T1 microstructures, little is known for additive manufacturing (AM). This work focusses on the comparative characterisation of T1 phase (structure, nucleation behaviour) in conventional (2099-T83), Powder Bed Fusion (PBF-LB/M) and Direct Energy Deposition (DED-LB/M) AA2099 microstructures. It is shown that with different AM processes and heat treatments, different T1 microstructures are achievable.
Optical Microscopy on Machined Surfaces in Ti-6Al-4V Reveals Pore Statistics that Correlate with Fatigue
Authors: Choi J , Zhou K , Adcock E , Pauza J , Ngo A , Swierzewski T , Lewandowski J , Rollett A D
Published: August 2024

Optical microscopy on the machined surfaces of 4-point bend fatigue samples 3D printed in Ti-6Al-4V is used to characterize pores larger than ≈15 microns. A large enough number of distinct scan speeds and fatigue tests that span the process window provides a statistically useful dataset. The variation in stress at which runouts (to 10 million cycles) are observed is anti-correlated with the pore density and the same inverse relationship exists for the maximum pore size observed within the area exposed to maximum tensile stress in each test. Total fatigue life is also anti-correlated with maximum defect size albeit with considerable scatter.
The Metallurgy of Additive Manufacturing: Potentials and Challenges towards Industrialisation
Authors: Mayr P , Rauh S , Matheson G , Rotzsche S , Hartmann S , Kabliman E
Published: August 2024

The present paper discusses the potential and challenges of processing metallic materials using additive manufacturing. Particular focus is given to laser powder bed fusion (PBF-LB/M) and the use of traditional alloy powders such as Al alloys and Ni-based superalloys, as well as novel materials such as metal-matrix composites. The research includes the improvement of the processability of these alloys using PBF-LB/M and optimizing material properties such as strength, creep resistance, and thermal conductivity of printed parts for various applications. Another important aspect presented within this manuscript is the digital representation of advanced manufacturing systems to improve manufacturability and enable advanced quality control. Herein, the development of a digital twin through in-situ process monitoring for the direct energy deposition process of laser metal deposition is presented. In the last part, the future of materials development for additive manufacturing is discussed, focusing on applying material computational techniques. All demonstrated examples result from the successful cooperation between the Chair of Materials Engineering of Additive Manufacturing, TUM, and its industrial and research partners.
Assessing and controlling microstructure heterogeneity in fusion-based additive manufacturing
Authors: Seita M
Published: August 2024

One of the de*ining features of fusion-based additive manufacturing (AM) is the localized melting of metal by a high-energy source, which fuses the material together point by point and layer by layer into a 3D object. The rapid solidi*ication velocity, directional thermal gradients, and site-speci*ic thermal build-ups produced by this process yield parts with complex and heterogeneous microstructure. This heterogeneity is a double-edged sword. On the one hand, it leads to large property scatter and casts uncertainty over parts performance, hindering the adoption of additive technologies by the industry. On the other hand, it may impart exceptional mechanical properties and new functionalities, which are not found in conventionally produced materials. In this paper, we present two ongoing research endeavours aimed at mitigating the detrimental effects of microstructure heterogeneity in AM, and at capitalizing on the opportunities it offers in the design of novel metal alloys, respectively. The *irst consists of developing a high-throughput characterization technique to enable large-scale microstructure analysis of AM builds. The second consists of a new strategy to control the material’s microstructure site-speci*ically during laser powder bed fusion.
An Image-Driven Machine Learning Method for Microstructure Characterization in Metal Additive Manufacturing: Generative Adversarial Network
Authors: Cao Z , Liu Y , Kruzic J J , Li X
Published: August 2024

The recent development of artificial intelligence especially machine learning technology has provided an emerging direction for solving microstructure representation and analysis in additive manufacturing. In this work, we introduce an advanced image-driven machine learning algorithm that offers an effective way to abstract the features in microstructure and generates high-resolution and large-size images that can represent the original counterparts. The evolution of the model and the potential application of the algorithm in material science are also discussed.
Improved corrosion resistance of powder manufactured AISI 904L parts by hot isostatic pressing post treatment
Authors: Sorea A , Valler P , Kjeldsteen P , Hjelmeborn P
Published: August 2024

Metal binder jetting (MBJ) of AISI 904L super austenitic stainless steel makes it possible to produce complex components with a higher corrosion resistance compared to austenitic stainless steels such as AISI 304L and AISI 316L. The initial sintering trials resulted in a porous part with low corrosion resistance. As AISI 904L is a steel with austenitic phase throughout the entire sintering window, densification during sintering was inhibited which resulted in the reduced corrosion resistance due to open porosities. The trials were made with AISI 904L powder suited for MBJ but shaped through metal powder extrusion due to lack of printer availability. This paper will show how to enhance densification and utilize pickling in order to improve the corrosion resistance closer to the expected level comparable to cast and rolled material but with the shaping possibilities of MBJ.
Processability of K340 Cold Work Tool Steel by Directed Energy Deposition Technique
Authors: Kenevisi MS , Martelli PA , Gobber FS , Ugues D , Biamino S
Published: August 2024

Directed Energy Deposition (DED) is an additive manufacturing process which can be used to repair defected components, such as blanking dies made of K340 tool steel. In this work, double tracks of K340 steel were deposited using DED process to study the processability of the alloy, and the tracks were characterized by light optical microscopy (LOM), scanning electron microscopy (SEM) and microhardness test. The results showed that near full-dense deposits can be made. However, the thermal cycle imposed by the process alters the microstructure of the material. Further investigation is required to make it possible to achieve a more homogeneous microstructure.
Challenges in characterizing additively manufactured AlSi10Mg using X-ray Laue micro-beam diffraction
Authors: Zhang Y , Defer M , Liu W , Knipschildt-Okkels E F F , Oddershede J , Slyamov A , Bachmann F , Lauridsen E , Juul Jensen D
Published: August 2024

Additive manufacturing of metals using for example laser powder bed fusion systems generally results in grains of complex shapes with cellular structure of submicron sizes, accompanied by a high dislocation density. This paper presents preliminary results from characterizing an AlSi10Mg alloy manufactured by L-PBF using non-destructive three-dimensional X-ray Laue micro-beam diffraction. Both synchrotron and laboratory X-ray methods are used. The aim is to identify challenges in characterizing these microstructural features and to propose future research directions to address them.
Understanding fatigue crack propagation pathways in Additively Manufactured AlSi10Mg
Authors: Rangaraj S , Ahmed S S I , Davis A , Withers P J , Gholinia A
Published: August 2024

Alloys produced through additive manufacturing (AM) offer substantial advantages, particularly in controlling material utilisation and precisely manipulating processing parameters, resulting in finely tuned material properties. However, the grain structure of AM material is typically complex, influenced by factors such as solidification dynamics, processing parameters, thermal gradients, and residual stress. Fatigue analysis shows considerable scatter due to entrained defects which limits their use as structural components. In this study, fatigue-failed samples from selective laser melted (SLM) AlSi10Mg alloy, oriented horizontal and vertical to the build direction were analysed to understand crack propagation paths. Here X-ray Computed Tomography (CT) was used to examine internal porosity from which fatigue cracks initiate, complemented by electron backscattered diffraction (EBSD) mapping. This enabled us to recognize the crucial role of the complex grain microstructure in controlling fatigue crack propagation.
Characterization of Si particles in additively manufactured AlSi10Mg using synchrotron transmission X-ray nanotomography
Authors: Defer M , Dasgupta S , Shahani A J , Xiao X , Juul Jensen D , Zhang Y
Published: August 2024

In AlSi10Mg samples manufactured by Laser Powder Bed Fusion, distinguishing the Si eutectic network/Si particles from the Al matrix by X-ray imaging is challenging due to the low absorption contrast between the Al and Si. This work investigates the possibility of overcoming this obstacle in synchrotron transmission X-ray microscopy. Effects of both different defocusing conditions and X-ray beam energies are evaluated and optimal conditions are identified for imaging a sample annealed post-print for 2h at 520°C. It is shown that both large particles (e.g. 4μm) and particles as small as 0.5 μm, can be imaged with reasonable precision in 3D non-destructively.
Influence of printing parameters on part density in L-BPF of Ti-6Al-4V and correlation with static mechanical properties measured using indentation testing
Authors: Schulz J , Santos E C , Kalliath A , Schmaling B , Zok P , Siegert S , Dandu I S , Lindner KH , Bruder E , Durst K
Published: August 2024

A complete workflow of parameter development and process qualification of a part manufactured using laser powder bed fusion (L-PBF) AM technique requires data of porosity, pore morphology, distortion and static mechanical properties. Using a combination of two non-destructive techniques: Computed tomography and indentation testing, the influence of printing parameters on defect types and part density in L-PBF of Ti-6Al-4V is described. In addition, the results using the combined method are compared to conventional testing methods.
Effect of microstructural heterogeneity and grain morphology on the annealing behavior of additively manufactured metastable β titanium alloy
Authors: Chang J Q , Wu Y N , Zhang Z B
Published: August 2024

Titanium alloys fabricated by additive manufacturing usually exhibit significant heterogeneity in grain size and morphology. Recrystallization treatment is an effective approach to alter the microstructure and achieve a more homogeneous structure. In this study, recrystallization and grain growth behaviours of a metastable β titanium alloy fabricated by laser powder bed fusion (LPBF) and direct energy deposition (DED) were investigated. The LPBF sample developed a chessboard-like microstructure, with considerable variations in grain size and morphology across molten pools. Recrystallization started from the boundary of these pools, where grains were finer and the stored energy was higher. The DED sample had a heterogeneous structure with alternating layers of equiaxed grains and columnar grains oriented with <100> along the building direction. Results obtained from in-situ EBSD demonstrated that grain growth occurred preferentially in regions with fine equiaxed grains, and regions with columnar grains showed limited grain growth due to the relatively lower driving force and mobility.
Cold spray - a solid-state additive manufacturing technology
Authors: Su Congcong , Wang Yan , Che Hanqing , Yue Stephen , Huang Xiaoxu
Published: August 2024

Cold spray is a solid-state powder deposition technique and has evolved into an additive manufacturing process. Unlike conventional additive manufacturing technologies that rely on melting and solidification, cold spray additive manufacturing (CSAM) forms components at low temperatures at a relatively high build rate. This article introduces the technical principles, process parameters and typical microstructure of cold spray, as well as its applications in the fabrication of 3D components and damaged component repair. Current issues faced in cold spray research and future development directions in CSAM are also discussed.
Investigation of dynamic characteristics and fatigue life prediction of Pb free solder material under random vibration
Authors: K Saravanakumar , Saravanan S , Muthuram N
Published: August 2024

Electronic packages are employed in diverse industries, including automotive, aerospace, and defense. However, their susceptibility to failure arises from exposure to uncontrolled operating conditions, particularly vibrations.Therefore, an investigation has been conducted to explore the effect of vibration in fatigue life of SAC305 lead free solder material employed in Printed Circuit Board (PCB) assembly with ball grid array (BGA) 144 electronic package. Finite Element Analysis (FEA) of a printed circuit board with BGA 144 electronic package was conducted to find their dynamic characterisics like natural frequencies and their mode shapes. Experiments were conducted to validate the numerically developed model, where first, second and third modes shapes from FEA and experimental results were compared. In addition, random vibration analysis was performed using numerical simulation where individual solder balls were analysed for stress distribution and experimentswere conducted on specially fabricated PCBs using electro dynamic shaker for validation. Analysis shows that the failure was prominent at the solder balls located at the corner of the package. Further, Minor’s rule was used to estimate the fatigue life of the Pb free solder material in BGA 144 package.
Hardware requirements for trapped-ion-based verifiable blind quantum computing with a measurement-only client
Authors: van Dam J , Avis G , Propp Tz B , Ferreira da Silva F , Slater J A , Northup T E , Wehner S
Published: August 2024

In blind quantum computing (BQC), a user with a simple client device can perform a quantum computation on a remote quantum server such that the server cannot gain knowledge about the computation. Here, we numerically investigate hardware requirements for verifiable BQC using an ion trap as server and a distant measurement-only client. While the client has no direct access to quantum-computing resources, it can remotely execute quantum programs on the server by measuring photons emitted by the trapped ion. We introduce a numerical model for trapped-ion quantum devices in NetSquid, a discrete-event simulator for quantum networks. Using this, we determine the minimal hardware requirements on a per-parameter basis to perform the verifiable BQC protocol. We benchmark these for a five-qubit linear graph state, with which any single-qubit rotation can be performed, where client and server are separated by 50 km. Current state-of-the-art ion traps satisfy the minimal requirements on a per-parameter basis, but all current imperfections combined make it impossible to perform the blind computation securely over 50 km using existing technology. Using a genetic algorithm, we determine the set of hardware parameters that minimises the total improvements required, finding directions along which to improve hardware to reach our threshold error probability that would enable experimental demonstration. In this way, we lay a path for the near-term experimental progress required to realise the implementation of verifiable BQC over a 50 km distance.
An efficient compact blazed grating antenna for optical phased arrays
Authors: Farheen Henna , Joshi Suraj , Christoph Scheytt J , Myroshnychenko Viktor , Förstner Jens
Published: August 2024

Phased arrays are vital in communication systems and have received significant interest in the field of optoelectronics and photonics, enabling a wide range of applications such as LiDAR, holography, and wireless communication. In this work, we present a blazed grating antenna that is optimized to have upward radiation efficiency as high as 80% with a compact footprint of 3.5 µm × 2 µm at an operational wavelength of 1.55 µm. Our numerical investigations demonstrate that this antenna in a

64
×
64

phased array configuration is capable of producing desired far-field radiation patterns. Additionally, our antenna possesses a low side lobe level of −9.7 dB and a negligible reflection efficiency of under 1%, making it an attractive candidate for integrated optical phased arrays.
Magnetostrictive assisted free and forced vibration response of layered functionally graded circular plate with effect of prestress
Authors: Patil Mukund A , Kadoli Ravikiran
Published: August 2024

One of the optimization requirements for improving the performance of magnetostrictive materials is prestress, which improves the magnetostriction coefficient. The influence of prestress on the fundamental frequencies and vibration suppression of a smart functionally graded circular plate is examined in the current work. The coupled differential equations regulating the motion are derived using Hamilton’s principle. This paper proposes using Kerr’s foundation as a flexible support structure for the disc braking system assembly. The Dirac-delta function and differential quadrature technique have been used to quantitatively simulate the forced vibration behaviour of a circular plate under moving loads. The accuracy and validity of the method used are tested by comparing numerical results to those that have already been published.
Investigation on the effects of deposition strategy on the mechanical characteristics and microstructure of austenitic stainless steel 308LSi manufactured via wire arc additive manufacturing
Authors: Osman Mohd Hairizal , Alkahari Mohd Rizal , Paijan Lailatul Harina , Yusri Nur Ayuni Ashyira Mohamad
Published: August 2024

This study examines the impact of deposition strategy on ASS 308LSi thin-walled structure manufactured via the Wire Arc Additive Manufacturing (WAAM) technique on the microstructural characteristics, tensile strength, microhardness, Charpy impact testing, and fracture morphology of the WAAM 308LSi. The analysis of the microstructure reveals that the deposition strategy promotes transitioning from columnar to equiaxed fine grain structure. The tensile strength results show that specimens with a 45° deposition strategy exhibit lower anisotropy and higher tensile properties compared to those with a 0° deposition strategy, with improvements of 33.1% in the transverse direction and 26.7% in the longitudinal deposition directions, respectively. The microhardness in WAAM SS308LSi demonstrates variations in the bottom, middle, and top regions, with the highest average value observed at a 45° deposition strategy (213.3 ± 6.5 HV, 201.1 ± 10.7 HV, and 191.5 ± 5.2 HV) as well. The impact testing results indicate that the highest absorbed energy occurs at a 45° deposition strategy, with 75 ± 4.2 J and 74 ± 4.0 J for the transverse and longitudinal directions, respectively. The fractures observed during testing exhibit ductile characteristics, with the presence of dimples and particles. This study demonstrates the significant potential of the 45° deposition strategy with the implementation of double-sided substrate deposition, resulting in a refined microstructure, nearly isotropic behavior, and excellent mechanical performance.