Engineering Commons^™

Engineering, Innovation, And God’S Creation, Fred Haan

University Faculty Publications and Creative Works

Took place at YPPH Annual Retreat 2025 Coram Deo In the Presence of God Reflections on Biblical Christian Worldview at Pelita Harapan University on 9/26/2025 in Jakarta, Indonesia.

Microstructure Densification In Cement Pastes Enabled By Novel Graphene Types, Sahil Surehali, Taihao Han, Ranjith Divigalpitiya, Aditya Kumar, Narayanan Neithalath

Materials Science and Engineering Faculty Research & Creative Works

The primary barriers hindering graphene's widespread adoption as a performance-enhancing additive in cement-based systems have traditionally been its prohibitive cost and the sustainability concerns associated with conventional manufacturing processes. However, these impediments have recently been mitigated by advancements in detonation synthesis techniques, enabling scalable, cost-effective, and environmentally favorable production of novel graphene types—specifically fractal graphene (FG) and reactive graphene (RG). This paper explores the influence of ultra-low dosages of FG and RG (≤ 0.04 % by mass of cement, which results in ∼20 % increase in compressive strengths) on the pore-structure features of cement pastes. Compared to the control paste, …

Magnesium Sulfate Attack Of Alite Paste And Mitigation By Surface Carbonation: Monitoring And Comparison Using Novel Portable Fiber-Optic Raman Probe, Bohong Zhang, Gao Deng, Hongyan Ma, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Sulfate attack on cement matrix is still a "confused world" especially when magnesium sulfate (MgSO₄) is the sulfate source. Accurate assessment of sulfate attack is essential for evaluating the structural integrity and durability of concrete in relevant environments. This study presents a portable fiber-optic Raman probe approach with 125 μm spatial resolution, designed for depth-resolved sulfate ingress monitoring in tricalcium silicate (C₃S, Alite) pastes. The probe is also used to evaluate the effectiveness of surface carbonation in mitigating sulfate attack. The results demonstrate a strong correlation between sulfate penetration depth and Raman spectral intensity ratios of sulfate-related vibrational …

Improvement Of Lithium-Metal Electrode All-Solid-State Batteries Performance By Shot Peening And Magnetron Sputtering, Atsuro Okumura, Manabu Kodama

15th International Conference on Shot Peening

To enable fast charging in lithium-metal anode all-solid-state batteries, suppressing lithium dendrite formation at the solid electrolyte (SE) interface is critical. Increasing fracture toughness via shot peening (SP) and improving interfacial contact with Au sputtering can inhibit dendrite growth. However, conventional sputtering may reduce toughness due to localized thermal damage. This study investigated magnetron sputtering as a low-damage, plasma-based Au deposition method. SEs with and without SP were fabricated and coated via normal and magnetron sputtering. Critical current density (CCD) and fracture toughness were evaluated. Without SP, CCD improvement was limited regardless of sputtering method due to poor bonding. With …

Hydrogen Embrittlement In Shot-Peened Steel, Jia-Huei Tien, David R. Johnson, David Bahr

15th International Conference on Shot Peening

This work investigates the role of shot peening on hydrogen embrittlement resistance in quenched and tempered 1070 steel. Thermal desorption spectroscopy results revealed that shot-peened specimens contained nearly twice the hydrogen (H) content of unpeened samples when charged under the same electrochemical conditions, suggesting the introduction of additional trapping sites occur during peening. The mechanism underlying this behavior can be associated with increased dislocation density and is more consistent with the HELP mechanism. Residual stress measurements show a significant relaxation of compressive stresses in shot-peened specimen after H charging, indicating H enhanced dislocation rearrangement. Both unpeened and peened specimens exhibited …

Investigation Of Topography Changes Of Blasted Surfaces: An Experimental Perspective Using Fiducial Markers, Stefanie Stoeckel, Sophie Groeger

15th International Conference on Shot Peening

Abrasive blasting is a process that intentionally modifies surface topography to meet specific functional requirements. The blast media is accelerated and interacts directly with the surface through impact. It is evident that the number of impacts and the overlap increase with time. This study aims to investigate these alterations to surface topography through repeated examinations of the same location. A methodology has been developed that employs the use of fiducial markers, which are protected during blasting by a custom 3D-printed cover. This method was used to observe changes in the topography of smooth and rough initial surfaces that had been …

Anisotropic Residual Stress Measurements In Additively Manufactured 316 Stainless Steel Parts, Rajeshree Varma, Donovan Stumpf, Paul R. Mort

15th International Conference on Shot Peening

Additive manufacturing (AM) using laser powder bed fusion (L-PBF) is increasingly used to produce complex parts for industries like aerospace and medical devices. The intrinsic characteristics of AM – layer-wise deposition and rapid thermal cycling – generate significant, anisotropic, residual stresses that can compromise part quality and performance. Recent studies highlight how these stresses are strongly influenced by process parameters and build orientation. X-ray diffraction (XRD) techniques, including sin²ψ and advanced two-dimensional approaches, have become the preferred methods for non-destructive, directionally resolved measurement of residual stress in AM metals. This review surveys advancements in XRD residual stress methods with a …

From Strain To Stress: Stress Map Testing Of Almen Strips, Donovan Stumpf, Rajeshree Varma, Paul R. Mort

15th International Conference on Shot Peening

Almen strips have long been used to evaluate shot peening intensity, with arc height serving as a proxy for compressive residual stress. Stress mapping tests (SMT) in this work involve the controlled flattening of an Almen test strip onto a spatial pressure sensor, acting as an inferential measurement for the net bending moment caused by the relaxation of the peened strip. This work explores how stress mapping tests add insight into the stress state of Almen strips, potentially offering a fast and practical alternative to residual stress depth profiling. SMT data analysis provides a framework for relating Almen gauge height …

A Novel Scaffold-Based Model For Stage Ii Pressure Injury Simulation: Protocol Development And Future Directions In Tissue Engineering, Skyler B. Wrubleski

Undergraduate Research and Scholarship Symposium

This study developed a 3D tissue-engineered scaffold to mimic human sacral skin for modeling pressure injuries. The scaffold consisted of a composite hydrogel of sodium alginate, gelatin, and tannic acid, crosslinked with calcium chloride. Swelling tests showed moderate hydration capacity, while wound mimic formation using a custom 3D-printed apparatus produced consistent morphology and dimensions comparable to human dermal tissue. The scaffold maintained structural integrity under prolonged compressive forces, demonstrating viability for pressure injury studies. Future work will incorporate a bilayer model with keratinocytes and fibroblasts and introduce elastin to enhance elasticity and mechanical properties. This approach aims to improve in …

Fourier Analyses Of Optical Profilometry As An Inferential Measurement For Impact Coverage., Langdon Feltner, Paul Mort

15th International Conference on Shot Peening

A critical consideration in peening process design is achieving sufficient impact coverage. Conventional methods for assessing coverage rely on manual inspection, which is time-consuming and poorly suited for automated control. In this work, we investigate the use of frequency-domain analysis to quantify surface modification in peened samples using optical profilometry (OP) data. Three-dimensional surface maps of Almen strips were acquired using a high-resolution OP system and analyzed via fast Fourier transform (FFT) to compute spatial power spectral densities (PSDs). PSD maps and radially averaged profiles reveal consistent amplification of harmonic components similar to the nominal particle size, with increasing intensity …

Enhancing High Cycle Fatigue Perfomance Of Electron Beam Melted Ti6al4v: A Study On Shot Peening And Hot Isostatic Pressing, Naghmeh M. Mojib, Dwayne D. Arola, Ramulu Mamidala

15th International Conference on Shot Peening

The qualification of electron beam powder bed fusion (PBF-EB) for safety-critical applications is hindered by variability in high cycle fatigue performance, largely due to surface roughness and internal defects. While Hot Isostatic Pressing (HIP) effectively reduces internal porosity, it does not address surface-initiated fatigue failures. This study investigated the combined effects of HIP and shot peening on enhancing the fatigue performance of PBF-EB Ti6Al4V. Over 50 specimens, including both vertical and horizontal build orientations, underwent high cycle fatigue testing per ASTM E466. X-Ray computed tomography confirmed decrease in defect distribution following HIP, while shot peening resulted in a more uniform …

Comparison Of Peening Effect Between Additive Manufacutred And Drawing Titanium Alloy, Hitoshi Soyama

15th International Conference on Shot Peening

Although additively manufactured (AM) metals are attractive materials, their remarkable weak fatigue properties are an obstacle to their practical application. Thus, post-processing to improve their fatigue properties is required. In the present study, powder bed fusion using laser sintering titanium alloy, i.e., PBF-LS/Ti6Al4V was treated by shot peening (SP), submerged laser peening (SLP), cavitation peening (CP), and fine particle bombarding (FPB), then the fatigue properties were investigated by a torsional fatigue test, comparing with drawing Ti6Al4V. It was revealed that the fatigue strength at 10⁷ was 446 ± 5 MPa for PBF-LS/Ti6Al4V treated by FPB+CP, 359 ± 9 MPa …

Improvement Of The Fatigue Behaviour Of Additive Manufatured Scalmalloy By Using Surface Improvement Processes, Francisco José Boby Alcaide, Irene Eras, José Manuel De Los Santos, Alejandro Munoz Castro, Antonio Perinan Butrón, Jorge Sogorb

15th International Conference on Shot Peening

The use of light metals such as Aluminum alloys has experienced a remarkable increase for the additive manufacturing (AM) industry, especially in aerospace.

AM Scalmalloy®. (an Al-Mg-Sc alloy) shows outstanding behavior with much higher mechanical performance with respect to other alloys for powder bed fusion laser-based (PBF-LB) process like AlSi10Mg or AlSi7Mg. Recent studies have mainly focused on static loading, with minor attention to cyclic loading despite its vital importance in many applications.

In this work, the fatigue performance of PBF-LB Scalmalloy was investigated considering the effects of surface treatments to identify the set of optimal post-processes. Shot peening with …

Influence On Shot Peening And Blast Polishing For Rotating Bending Fatigue Strength Of Vacuum Carburized Steel With Circumferential Notch, Yuji Kobayashi, Hayato Taniguchi, Kiyotaka Masaki

15th International Conference on Shot Peening

In order to improve fuel efficiency in automobiles, weight reduction is necessary as well as improving engine efficiency. For transmission gears, thickness reduction is necessary for weight reduction. When the thickness is reduced, the cross-sectional area becomes smaller, and the load stress increases. Therefore, higher fatigue strength is required. Most gears carry out carburizing. Shot peening is often used to improve the fatigue strength of carburized heat-treated parts. After shot peening, compressive residual stress is introduced, but at the same time, surface roughness is increased. Therefore, the processing conditions of shot peening are very important. Blast polishing is a processing …

Reduced Order Approach For Peening Stress Field Variability, Langdon Feltner, Paul Mort

15th International Conference on Shot Peening

A common goal in shot peening research is to connect operational parameters to resultant residual stress fields, providing a means to control and optimize the effectiveness of surface treatment. In practice, experimental measurements of residual stresses are often averaged values over regions that are large in comparison to an impact dimple. In fact, the stochastic nature of impact locations leads to residual stress fields that are distributed. Finite element peening simulations confirm this observation. The goal of this report is to connect operational parameters to localized fluctuations in residual stress through probabilistic reasoning (Figure 1). In particular, the development of …

Adaptation Of Shot Peen Parameters For Gear Geometry, David J. Breuer, Beth Matlock

15th International Conference on Shot Peening

Shot peening is a well established process for the surface enhancement of gearing. Gearing is a primary example of a high cycle fatigue application that can benefit from residual stress enhancement. Designing shot peening parameters to specific gear geometry based on material, heat treatment, and surface finish is a more precise way to achieve better performance outcomes. One of the best tools to assist in the optimal shot peening is x-ray diffraction (XRD) and its ability to measure small differences that can result in significant performance outcomes. XRD residual stress measurements are a direct measurement of elastic strain. The diffraction …

Investigations On The Fatigue Strength Of Threads Produced By Different Fabrication Techniques, Philippe Du Maire, Jürgen Hoffmeister, Andreas Öchsner, Michael Johlitz

15th International Conference on Shot Peening

The increasing importance of sustainability in engineering demands the development of long-lasting, high-performance components that reduce material and energy consumption over time. This study investigates how different thread manufacturing processes, i.e., cutting, rolling, and deep rolling, affect the fatigue strength of bolts made from 42CrMo4+QT steel. Cylindrical specimens with M12 threads were subjected to cyclic tensile loading with constant mean stress. Fatigue strength was evaluated using the staircase method, and supporting analyses included X-ray diffraction for residual stress, and full width half maximum examination and Vickers microhardness measurements. Results show that thread rolling significantly improves fatigue strength, achieving 113.8 MPa …

Numerical Assessment Of Shot Peening Contribution To The Fatigue Strength Of Gear Tooth Root, Gurutz Cortabitarte Laucirica, Xuban Telleria, Iñigo Llavori, Ibai Ulacia, Miren Larrañaga, Jon Ander Esnaola

15th International Conference on Shot Peening

Gears are commonly treated with shot peening (SP) and/or case hardening to enhance fatigue resistance. However, their effects are often conservatively assessed using standardized methods, which can limit their optimal application in industrial components. Particularly, the effect of SP over case-hardened gears remains insufficiently explored. Therefore, the present study evaluates the contribution of SP on single tooth bending fatigue (STBF) strength of raw and case-hardened spur gears, commonly used in automotive and heavy machinery industries. In the study four conditions are addressed: (i) untreated, (ii) case-hardened, (iii) shot-peened, and (iv) case-hardened and shot-peened. First, the residual stress field of the …

Enrichment Factors And Play Fairway Mapping Of Helium In Typical Zones Of The Ordos Basin, Gao Jianrong, Tao Shizhen, Liu Xiangbai, Yang Wei, Zhao Zhenyu, Chen Xiuyan, Xu Wanglin, Zhang Chunlin, Song Wei, Chen Yue, Huang Junping, Ma Zhanrong

Coal Geology & Exploration

Background The Ordos Basin enjoys abundant natural gas resources, which generally bear helium, making this basin hold great helium resource potential. In this case, detailed exploration is essential for the future transition from natural gas-helium joint exploration to special helium exploration in the basin.Objective and Method To systematically investigate the distribution and potential of helium resources in the Ordos Basin, natural gas samples were taken from different areas of the basin for analysis and tests. To examine the primary factors controlling helium accumulation and enrichment, this study conducted a systematic analysis of the basement, sedimentary rock layers, fault systems, …

Bachelor's Degrees And Earnings In The Mountain West, 2022, Anthony Arroyo, Sydney Mitchell, Lara Karaalp, Caitlin J. Saladino, William E. Brown Jr.

Higher Education

This fact sheet presents 2022 data on the median annual earnings of bachelor's degree holders for specific fields of degrees (FODs) across the five Mountain West states of Arizona, Colorado, Nevada, New Mexico, and Utah. This fact sheet also examines the share and earnings of individuals with less than a bachelor’s degree compared to bachelor’s degree holders in the three Mountain West metropolitan statistical areas (MSAs) appearing among the 30 largest MSAs in the United States: Phoenix-Mesa-Chandler, AZ; Denver-Aurora-Lakewood, CO; and Las Vegas-Henderson-Paradise, NV. The “Field of Bachelor's Degree in the United States: 2022” report from the U.S. Census Bureau …

High-Precision Reconstruction Of Seismic Data Based On Improved U-Net++, Wang Minling, Zhou Fei, Wang Honghua, He Xiang, Hou Zhiyang

Coal Geology & Exploration

Objective Conventional reconstruction methods are insufficient for the reconstruction of seismic data with missing consecutive traces, producing a negative impact on subsequent processing accuracy. Hence, this study proposed CU-Net++, a deep learning network based on the U-Net++ architecture combined with the convolutional block attention module (CBAM). Methods During the reconstruction of missing data, the independent decoder for each sub-U-Net in the nested U-Net++ architecture enables the utilization of information from different depths. The long and short skip connections can effectively enhance the network's capability to extract multi-scale features from data. The core innovation of CU-Net++ is the introduction of CBAM, …

Application Of Geophysical Logging To Selection Of Optimum Target Horizons For Salt Cavern Storage: A Case Study Of Borehole Zk01 In Qingjiang Salt Mine, Jiangxi Province, China, Liu Dongming, Lin Zhenzhou, Liu Dongyan, Qiu Changyi, Liang Mingxing, Zhai Jinghong, Zhang Jie, Jiang Zhengzhong

Coal Geology & Exploration

Background Under the guidance of the strategies to achieve the goals of peak carbon dioxide emissions and carbon neutrality, salt cavern storage facilities, serving as key infrastructure for clean energy strategic reserves, have emerged as a core approach to promoting the transformation and upgrade of the salt industry and to building a low-carbon energy system in China. Jiangxi Province, located in the middle part of the Yangtze River Economic Belt, is endowed with abundant salt rock resources, making it a national priority zone for developing resources for salt cavern storage. However, traditional methods for the siting of the facilities rely …

Process And Mechanism Of Defluorination Using Magnesium Chloride-Modified Coal Gangue, Zhao Li, Zhou Wangxu, Zhang Qing, Xing Mingfei, Xu Feng, Kong Weifang, Liu Yifei, Qin Guangyu

Coal Geology & Exploration

Background The rapid development of industry has resulted in a yearly increase in wastewater discharge, which induces a gradually rising fluorine concentration in water. In this context, removing fluoride using natural materials and industrial waste has emerged as a popular research topic. Coal gangue, one of the largest contributors to industrial waste in China, contains substantial clay minerals, and its pore structure can be effectively improved through modification. This helps significantly enhance its adsorption performance and thus achieve efficient fluoride removal from water. Methods This study investigated coal gangue from a typical mining area of the Henan Energy and Chemical …

A Modular Casing While Drilling Rig For Large-Diameter Horizontal Boreholes For Underground Rescue, Fan Dong, Ni Xiaoyang, Mu Shuyuan, Zou Zujie, Wen Guojun, Li Yingping, Lu Feifei

Coal Geology & Exploration

Objective Operations in a narrow space pose a challenge to rescue in the case of the collapse of mine roadways or tunnels. To address this challenge, this study developed a modular rescue casing while drilling (CwD) rig system for horizontal boreholes. With the capacity for quick responses, this CwD rig was designed to enhance the rescue efficiency and safety under complex geological conditions. Methods Following the modular design concept and compact layout principle, this study optimized core components such as the power heads, feed devices, and power system. The auxiliary operation vehicle was checked against overturning through multibody dynamics (MBD) …

Structural Optimization For Transfer Chutes Based On Energy Dissipation Mechanisms Of Coal Particles, Shi Yaocheng, Zou Zujie, Wen Guojun, Cheng Siyi, Wu Laijie, Wang Yudan, Liu Pu, Chen Mengxi

Coal Geology & Exploration

Objective Bulk material transport in emergency rescue scenarios and coal transportation poses stringent demands for the structural performance of transfer chutes. Given this, from the perspective of the energy dissipation mechanisms of particles, this study proposed structural optimization methods for transfer chutes based on the regulation of particle energy dissipation. Methods An experiment–simulation integrated analysis framework was established. Using this framework, this study systematically simulated the impact process of particles between two-stage walls I and Ⅱ using the discrete element method (DEM), highlighting the coupling mechanisms among velocity fluctuations, stress distribution, and energy transformation pathways. Based on the results, this …

A Simulation And Experimental Study Of Bottomhole Flow Field In A Large-Diameter Rescue Borehole, Zhao Yan, Liu Songhe, Hao Shijun, Zhao Jiangpeng, Li Peishu, Wang Xuebo, Yu Yongping, Gao Ke, Dong Bo, Zhang Bo

Coal Geology & Exploration

Objective In mine rescue, reaming using a large-diameter down-the-hole (DTH) hammer faces is challenged by complex bottomhole flow fields and difficult slag discharge. This study aims to address these challenges. Methods To reveal the influence patterns of drilling parameters on the bottomhole flow field and slag discharge efficiency, this study determined the optimal drilling parameter combination. Then, using the computational fluid dynamics (CFD)-discrete phase model (DPM) method, this study established a numerical model for the slag discharge and bottomhole flow field during the reverse circulation drilling using a DTH hammer. Relying on this model, this study analyzed the variation patterns …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Injection-Production Process Parameters Of Well Group Configurations For Autothermic Pyrolysis In Situ Conversion Of Oil Shale, Zeng Yijian, Zhu Chaofan, Li Yanwei, Shui Haoche, Guo Wei

Coal Geology & Exploration

Background A well group acts as a multi-well synergistic unit, and its configuration directly determines both the selection of optimal injection–production process and the utilization efficiency of stratigraphic conditions, ultimately affecting the overall performance of resource recovery. Methods Using numerical simulations, this study assessed the performance of autothermic pyrolysis in situ conversion (ATS) under three vertical well group configurations: one injection well and one production well (1I1P), one injection well surrounded by four production wells (1I4P), and one injection well surrounded by six production wells (1I6P). Furthermore, it revealed the synergistic mechanisms between well group configuration and energy efficiency. Results …

Attenuation Characteristics And Wave Impedance Inversion Of Depth-Domain Nonstationary Seismic Data, Ma Ming, Ma Feng

Coal Geology & Exploration

Background The efficient application of depth migration methods has enabled the extensive implementation of depth-domain seismic data interpretation. Previous studies on the impacts of time-to-depth conversion and velocity models merely determine that an increase in depth corresponds to reduced dominant wavenumber of seismic waves and waveform stretching, without considering the changes in amplitude and phase. Objective This study aims to accurately characterize the waveforms of nonstationary seismic signals in the depth domain and enhance the impedance inversion accuracy. Methods First, based on energy dissipation and frequency dispersion effects during the propagation of seismic waves, this study investigated the complex mapping …

Analysis Of The Connotation Of Hidden Disaster-Causing Factors In Coal Mines And The Key Points Of Their Reconnaissance, Lian Huiqing, Wang Xu, Yin Shangxian, Xia Xiangxue, Cao Min, Li Qixing, Wu Xiaoming, Zhang Bin, Wang Yangyu, Zhang Qing, Wang Guo’An

Coal Geology & Exploration

Background To systematically normalize the reconnaissance of hidden disaster-causing factors in coal mines, the National Mine Safety Administration issued the Specification for General Survey of Hidden Disaster-causing Factors in Mine in 2024. Nevertheless, coal mining enterprises still face a range of notable issues in reconnaissance of hidden disaster-causing factors, including ambiguous connotations of the factors, broad scopes of reconnaissance, unclear implementation stages, a disjunction between explorations and reconnaissance, and improper conclusion descriptions. These problems severely restrict scientific and operational reconnaissance.Methods This study reviews the history of research on the reconnaissance of hidden disaster-causing factors, presents a summary of significant …