Detailed Engineering Research Articles

Low carbon development of science and techno park (STP) pollung in North Sumatera Province

The development of Science and Techno Park (STP) is one of the government’s efforts to increase competitiveness in the science and technology sectors as well as to improve the regional and national economy. Relevant to this, the government has planned the development of the herbal and horticultural sectors known as the Science and Techno Park of Herbal and Horticultural (STPH2). It is located in Pollung, North Sumatera Province, specifically in the Forest for Specific Purpose (KHDTK). In line with the government’s program to reduce greenhouse gas (GHG) emissions, the planning of the STP development has used the principle of Low Carbon Development (LCD) as it will bring many benefits from reducing carbon emissions which also supports sustainable regional development programs. This research was carried out by reviewing the STPH2 planning documents, such as the master plan and Detailed Engineering Design (DED), which was followed by identifying components that could reduce carbon emissions and absorb carbon emissions. The results of these findings are then compared with references. The conclusion shows that the planned components, such as building design, land cover, and water and waste management systems have followed the LCD principle.

STUDI TEKNO EKONOMI PERENCANAAN PEMBANGKIT LISTRIK MIKRO HIDRO (PLTMH) DI KECAMATAN KARERA KABUPATEN SUMBA TIMUR

This study aims to measure the water potential of the Pahambur Wai River, in Nggongi Village, Karera District, East Sumba Regency to be used as a driving source for Micro Hydro Power Plants.This study aims to measure the water potential of the Pahambur Wai River, in Nggongi Village, Karera District, East Sumba Regency to be used as a driving source for Micro Hydro Power Plants. The research methods used are observation, area mapping, measurement of water flow and elevation, calculation of potential for electric power generated, Detail Engineering Design, cost calculation and economic feasibility.From the analysis and calculation, the maximum water flow of the Pahambur Wai River is 1,687 m3/s, minimum water flow is 0.054 m3/s. Probability availability is 70%, or 0.240 m3/s, with an effective elevation of 15 meters. The actual electric power generated is 20.44 kW. Type of turbine of MHPP is the Crossflow T14, D300 turbine, and coupled using a V belt, to a 3 phase synchronous generator, with a capacity of 25 kW.The plan for the construction and operation of the MHPP is economically feasible, as can be seen from the indicators of investment feasibility NPV, IRR, and Profitability Index.

Iceberg-seabed interaction analysis in sand by a random forest algorithm

Iceberg-seabed interaction that threatens subsea pipelines and structures is a challenging and costly engineering design aspect of Arctic offshore infrastructures. In this study, the sub-gouge soil deformation in the sand along with the keel reaction forces was simulated using Random Forest (RF) as a strong machine learning (ML) model and compared with the Gradient Boosting Model (GBM), and Support Vector Regression (SVR) as other alternatives. Nine RF models were built based on the most influential parameters and the best model was identified by performing a sensitivity analysis. The study showed that the proposed RF model outperformed its counterparts and proved to be a cost-effective and reliable alternative to assess the iceberg-seabed interaction in the sand, particularly at the early stages of the projects, where a fast and accurate estimation is required for planning the construction methodologies, logistics, and the scope of detailed engineering.

Design engineering a walking robotic manipulator for in-space assembly missions.

In-Space Services aim to introduce sustainable futuristic technology to support the current and growing orbital ecosystem. As the scale of space missions grows, there is a need for more extensive infrastructures in orbit. In-Space Assembly missions would hold one of the key responsibilities in meeting the increasing demand. In the forthcoming decades, newer infrastructures in the Earth’s orbits, which are much more advanced than the International Space Station are needed for in-situ manufacturing, servicing, and astronomical and observational stations. The prospect of in-orbit commissioning a Large Aperture Space Telescope (LAST) has fuelled scientific and commercial interests in deep-space astronomy and Earth Observation. However, the in-situ assembly of such large-scale, high-value assets in extreme environments, like space, is highly challenging and requires advanced robotic solutions. This paper introduces an innovative dexterous walking robotic system for in-orbit assembly missions and considers the Large Aperture Space Telescope system with an aperture of 25 m as the use case. The top-level assembly requirements are identified with a deep insight into the critical functionalities and challenges to overcome while assembling the modular LAST. The design and sizing of an End-over-end Walking Robot (E-Walker) are discussed based on the design of the LAST and the specifications of the spacecraft platform. The E-Walker’s detailed design engineering includes the structural finite element analysis results for space and earth-analogue design and the corresponding actuator selection methods. Results of the modal analysis demonstrate the deflections in the E-Walker links and end-effector in the open-loop due to the extremities present in the space environment. The design and structural analysis of E-Walker’s scaled-down prototype is also presented to showcase its feasibility in supporting both in-orbit and terrestrial activities requiring robotic capabilities over an enhanced workspace. Further, the mission concept of operations is presented based on two E-Walkers that carry out the assembly of the mirror modules. The mission discussed was shortlisted after conducting an extensive trade-off study in the literature. Simulated results prove the dual E-Walker robotic system’s efficacy for accomplishing complex in-situ assembly operations through task-sharing.

A simulation study on proton accelerator-based sources for BNCT of shallow tumors

Boron Neutron Capture Therapy (BNCT) is considered as a cancer treatment method with less damage to healthy tissue during tumor destruction. Accelerator-based neutron sources, including proton accelerators, have been considered as appropriate candidates in the BNCT of deep-seated tumors. However, there is less attention to using high-energy proton accelerators for the treatment of shallow tumors. The present work investigates the possibility of using proton accelerators to provide a neutron beam for the treatment of shallow tumors by using the MCNPX Monte Carlo code. An optimized Be target has been used to produce neutrons through the 9Be(p,n)9B reaction. Different materials were investigated to achieve an optimized Beam Shaping Assembly (BSA). After passing the beam through an arrangement of optimized materials, the neutron beam, checked against the in-air parameters recommended by IAEA, has been generated. Furthermore, a simulated phantom with realistic materials, including skin and the underlying soft tissue, has been used for dose evaluations. The beam performance has been examined through dose delivery in tumor compared with that in normal tissue using the simulated phantom. The results show that proton accelerator-based neutron sources have the potential to be considered as an appropriate candidate for the BNCT of shallow tumors. The results are encouraging to perform more detailed engineering and treatment planning studies to reach the clinical phase.

PEMBUATAN RANCANG BANGUN PRASARANA PUBLIK UNTUK PENGEMBANGAN ECO TOURISM BATU KATAK KECAMATAN BAHOROK – LANGKAT

Province of North Sumatra has tremendous potential of tourism. This tourism object can be enjoyed by tourists, both local and foreign. Some of the attractions of North Sumatra that can be visited are Lake Toba, Samosir Island, Sibolga Beach, Berastagi and Bahorok which is located in Langkat Regency. Another tourist destination included in the Gunung Leuser National Park area is Tangkahan. Tangkahan has a unique selling point because it is a habitat for Sumatran elephants. Another choice of place that is no less interesting and can be enjoyed by the beauty of the environment is the ecotourism of Batu Katak which is located in Batu Katak Hamlet, Batujongjong Village, Bahorok District, Langkat. In the tourism sector, two factor: benefits and satisfaction of tourist are related to Tourism Resource and Tourist Service. Tourist objects and attractions are everything that exists in a tourist destination area that has its own charm and is able to invite tourists to visit. To increase the number of local and foreign tourists in North Sumatra, the government of North Sumatra continues making more improvements to facilities of tourism destinations, including the development of human resources. Other infrastructure matters that are not yet complete are rest areas, clean toilets, prayer rooms, halal cuisine, and area pointers (maps, signs, and so on). The purpose of this research is to design public infrastructure that is needed for the development of eco-tourism Batu Frog. The infrastructure includes toilets, tourist interpretation boards, hand washing (sanitation) places, trash cans, and road/way signs. The infrastructure created must meet the requirements of Clean Health Safety Environmental Sustainability (CHSE). With this infrastructure, it is expected to provide better services for tourists so that the number of visits in North Sumatra continues to increase. The success of eco-tourism development in Batu Katak is also expected to increase the income and welfare of the surrounding community. The specific objectives of this research are 1) Designing environmentally friendly supporting infrastructure as an effort to improve services to tourists who meet CHSE requirements, and 2) Making Detailed Engineering Design (DED) or bestek of toilets, tourist interpretation boards, hand washing places. , trash cans and directional/road signs. The stages that will be carried out in this research are problem identification, setting research objectives, literature and field studies conducted by interview and direct observation. The next stage is data processing and designing the initial design proposal.

Determining the Reliability of A Seismically Assessed Building Conclusion Using A Modified FEMA P-154 Procedure

The quality of seismic risk management decisions depends on professional judgements. Such require an assessment of the reliability of the thought process and information used to give them credibility. The goal is to develop a process that assesses the reliability of a traditional P-154 assessment to determine whether it is sufficiently reliable to warrant action. P-154 is a triage approach meant to determine whether a detailed engineering assessment is required or not. Modifications to the P-154 procedures are proposed to warrant such actions without additional engineering assessment. This involves requiring highly experienced evaluators, specification of building document review, and technically independent supervision. Based on the nature of the conclusions, whether using the modifications or not, the reliability of the assessment can be evaluated, and a decision made whether it warrants action. It was validated by application to 56 likely hazardous buildings on three CSU campuses. The result of application of P-154 was that 52 of the 54 buildings need further engineering evaluation to reach a decision: two needed immediate attention, 12 requiring work overtime, where the reliability of all the evaluations indicated a good reliability for the conclusions, when the companion paper’s procedures for portfolio management were implemented. The application of the recommended approach was about $2,500 per building, including assessor time, travel, and expenses, more than the conventional P-154 cost but far less than the engineering P-154 assessment. A companion paper, Setting the Priority for Seismic Retrofit of Buildings Using a Modified FEMA P-154 [1] Procedure develops the seismic management program using this reliability determination as a key ingredient. The principal impact of the Modified P-154 process is that the retrofit decisions it recommended had acceptable reliability to CSU management and their advisors.

Modeling and Design Methodology for the Development of Electro-Optical and Laser Systems

Modeling and simulation (M&S) plays a key role in the development of all systems, but especially so in the development and integration of electro-optical (EO) subsystems and lasers for precision strike applications or counter measures that require precise pointing control. Since the development of the first EO and laser systems, the directed energy community has pursued an evolving modeling and design (M&D) approach to support the development of these systems to provide the data and insights needed for the acquisition process. M&D is the lower-level detailed engineering models that are used to define and perfect the design (mechanical, optical, electrical, software), whereas M&S is typically the higher-level engagement models embedded in the mission and war game simulations. When the M&S is closely tied to the M&D, the M&S will accurately represent the system capabilities and limitations. This paper presents an M&D methodology that has matured over the past years and continues to be applied on current EO and laser programs. Similar to other development methodologies utilized by government agencies and industry, the M&D methodology is critical for airborne EO-laser systems, where the operating environment is especially hostile to achieving microradian pointing accuracy and jitter stability in the optical line of sight. Applying the M&D methodology early and often throughout the development process in conjunction with the model-based systems engineering approach, the M&S can fully integrate into the life cycle of EO-laser programs from the development of requirements, the verification of design, the prediction and verification of performance, and the defining of system capabilities and limitations, to the maintenance and upgrades to the system. This disciplined connectivity of M&S to the M&D will lead to cost-effective EO-laser systems.

Feasibility Study dan Detail Engineering Design Pembangkit Listrik Tenaga Surya (PLTS) komunal di Universitas Teknologi Sumbawa

Sumbawa University of Technology (UTS) is an educational institution whose territory has the potential to establish a Solar Power Plant (PLTS), which has an average air temperature of 25oC. This temperature allows the solar module to work to convert solar energy into electrical energy. In this study using primary and secondary data on the UTS load profile, to design the PV mini-grid construction by conducting a feasibility study and calculating the detailed Engineering Design (DED) which includes the calculation of generating capacity, the number of solar modules, batteries, Solar Charge Controller (SCC). ), and the required Inverter. The results of this study indicate that the generating capacity needed by UTS is 1,542 MWp to supply 14 buildings with a daily electricity requirement of 513 kWh where this need is utilized during activity hours (at 07.30 to 17.00 WITA), then 1450 solar modules are needed with power output of 200 Wp, 189 Batteries with a battery capacity of 12 Volt 1000 Ah/unit, 8 SCCs with a Maximum Power Point Tracking (MPPT) interval of 64 -128 Volts, and 62 inverters with a capacity of 5000 wat/unit and Output voltage (Vac) of 240 Volt

Rock mass characterization and support analysis of pressurized headrace tunnel of the Upper Balephi “A” Hydroelectric Project, Nepal

Detailed geological, engineering geological and geotechnical assessment are prerequisites for any design works in underground excavation. Due to complex geology in young Himalayan, it is mandatory. Any misjudgment in support design may results huge losses of cost and time of the project. This paper encompasses detailed analysis carried out for examining the rock mass properties for optimum support along a pressurized headrace tunnel of Upper Balephi “A” Hydroelectric Project, Nepal. Empirical, analytical and numerical methods were applied for safe tunnel design. The rock mass quality and support in these areas were estimated using the rock mass rating (RMR), geological strength index (GSI) and rock mass quality (Q) systems. The detailed rock engineering assessment indicated that there are some critical locations along the headrace tunnel alignment. Rock mass quality values derived from different methods were used for calculating modulus of deformation, Hoek-Brown constants, strength of rock mass, in situ stresses, squeezing and support pressure using available empirical equations. The support determined from the empirical methods were evaluated for the overall stability of the required excavation by using finite element method. The analysis showed that the support pressure and deformation can be predicted very well and magnitude of the displacements and extent of the plastic zones can be reduced significantly by application of the support installation. The numerical modelling reveals that the support suggested by empirical methods are appropriate. Both empirical and numerical approaches are necessary for the confirmation of reliable support design of underground structure.

Evaluation of Metro Lines with Swarm Intelligence Approach

Metro lines, which have become one of the most important transportation routes for today's cities, require long design and implementation processes. Their design load is mostly due to detailed engineering calculations, have to expand to meet the needs of the ever-increasing population. The behavior of slime moulds to find the shortest path they use to reach the food source has inspired models created specifically to test the accuracy of highway routes. The hypothesis of this study is that the swarm behavior of slime moulds and the routes they follow may produce the same or similar results as the existing metro lines. In this research, an answer was sought to the question of whether a metro line designed with an approach based on swarm intelligence could be compatible with the existing line. The paper aims to develop a model that guides the design processes of metro lines by using swarm intelligence and shortest path finding strategies of slime moulds in a computational model. In the model, slime moulds were represented by multi-agent systems. The metro route was produced by the model using the station locations on an existing metro line selected as the study area. The agent-based simulation model was developed in the Grasshopper Physarealm plug-in environment. In the first stage of the model, a numerical model was created using the data and parameters of an existing metro line. In the second stage, the simulation was carried out to create a new route by preserving only the station locations of the existing metro line. Finally, the existing metro route and the route developed with the simulation model based on the intelligent agent behaviour in the digital environment were compared by overlapping. The results show that the route created by slime moulds only to reach the food is almost the same as the currently designed metro line. Topography data is ignored in the model. It is seen that the model developed by using metro design criteria is an important decision support aid for designers in determining metro routes.

Lyophilized platelets inhibit platelet aggregation with simultaneous paradoxical promotion of platelet adhesion.

Lyophilized platelets have been explored as a potential hemostatic agent due to their long-term ambient storage capabilities that make them readily available in various scenarios. Additionally, their high biocompatibility and the key role of platelet interactions in various clinical conditions make them a promising platform for drug delivery. To explore these applications and for wider clinical deployment, the interactions between lyophilized platelets and fresh platelets must be examined. This project characterized receptor expression on the lyophilized platelet surface and their ability to bind fibrinogen using flow cytometry. The effect of lyophilized platelets on aggregation of unaltered platelets was assessed using light transmission aggregometry while the effect on adhesion was evaluated using static and microfluidic assays. Lyophilized platelets maintained significant levels of GPIIb and GPVI receptors on their surface, though the expression was reduced from fresh platelets. Additionally, lyophilized platelets maintained GPIb expression similar to fresh platelets. Furthermore, 15.8% of the lyophilized platelets exhibited the active conformation of the GPIIb/IIIa receptor, indicating a significant increase over fresh platelets. Lyophilized platelets also exhibited an increase in exposed phosphatidylserine and fibrinogen binding. Despite the effect of lyophilized platelets in promoting the adhesion of fresh platelets on a collagen-coated surface, their net effect was inhibitory on platelet aggregation. This study demonstrates that lyophilized platelets can have paradoxical effects on platelet adhesion and aggregation, which could have an impact for clinical applications. Detailed characterization and engineering of these effects will be important for their continued development as a drug delivery platform.

Energy management of a parallel hybrid electric vehicle based on Lyapunov algorithm

Aiming at the time-consuming problem of basic dynamic programming (DP) algorithm and the fact that adaptive energy control management strategy (A-ECMS) cannot provide the optimal fuel consumption, this paper proposes highly integrated model of the vehicle coupling with a detailed engine model which is validated by the NEDC tested value. Then, an online energy management algorithm is proposed based on Lyapunov optimization analysis considering the system stability. The results show that (1) the cumulative fuel consumption obtained from the integrated model is 832.01g while the tested fuel consumption is 845.82g. The relative error between the simulated and tested fuel consumption is 1.63%. On this basis, the integrated model can be considered to predict the fuel economy of the vehicle with extraordinarily high accuracy. (2) Comparing the Lyapunov algorithm with DP and A-ECMS algorithms on a series parallel hybrid electric vehicle, the average fuel consumption of the proposed online energy management algorithm based on Lyapunov optimization is reduced by 13% compared with A-ECMS algorithm, which lays the foundation for the development of a unified algorithm platform. • An integrated model of the vehicle coupling with a detailed engine model is built. • Energy management of a PHEV based on Lyapunov algorithm is presented. • Fuel consumption of A-ECMS algorithm based on Lyapunov optimization is reduced by 13%.

Multi-scale design optimization of electric vehicles by analytical target cascading: From battery cell level to marketing level

The trend of vehicle electrification is rapidly growing and is likely to continue in the future. However, electric vehicles (EVs) with high vehicle performance, energy efficiency, and low cost are required to satisfy industry and customer needs. Design optimization is an important method that can significantly improve the performance of batteries and EVs. However, only a few studies integrate accurate full-order electrochemical models of lithium-ion batteries into optimization frameworks of the battery module, pack, and EV design owing to complex modeling with huge computational costs. Multi-scale models with high efficiency and accuracy are required to provide optimal design, considering the overall system across scales. This study develops an efficient multi-scale design optimization framework for EVs, including four levels from the battery cell level to the marketing level. In the engineering domain, three levels of fundamental physics-based models are developed—an electrochemical cell, thermal module, and EV dynamics—to describe the performance of EVs. In the marketing domain, a utility model is used to maximize profit while considering customer preferences and costs. In addition, the vehicle model at the top level of the engineering domain is linked with the marketing model. Thus, all four model levels are hierarchically connected and can pass information.The multi-scale design optimization problem is solved by applying an analytical target cascading (ATC) method specialized for multi-level optimization. Through the ATC framework, optimization problems at each level can be independently solved while satisfying the targets from upper levels. Results show that each level successfully communicates with the others and carries out optimization to maximize profit while satisfying various constraints. ATC reduces the computational cost by 3% compared to the conventional all-in-one (AIO) approach. Parametric studies provide insights into how these design parameters, constraints, and operating conditions affect each other. To the best of our knowledge, this study is the first attempt toward developing multi-scale level modeling of EVs, which covers the marketing (very high business level) down to the cell (very detailed engineering level) while satisfying multi-level safety constraints.

Reducing wheel–rail surface damage by incorporating hydraulic damping in the Bogie primary suspension

ABSTRACT Wheel–rail surface damage in curves can be effectively reduced with a lower vehicle Primary Yaw Stiffness (PYS), while lowering PYS is detrimental to ride comfort and vehicle stability. This trade-off can be addressed by integrating hydraulic damping into primary suspension. However, work in this area only concentrated on comparing the effects of specific devices – the full potential of the hydraulic-damping-integrated primary suspension on combating the trade-off considering the whole parameter space is still unknown. Here we address this by making the following two contributions: (1) fully exploring the potential of hydraulic-damping-integrated primary suspension, on minimising the PYS while maintaining ride comfort; (2) systematically investigating the trade-off between the PYS reduction and suspension stroke requirement. Based on a case study using the Mark 4 Coach, this paper found that the optimal hydraulic-damping-integrated suspension can reduce PYS by 97% over the default without worsening comfort. This large reduction can potentially lead to a significant lifetime wheel-rail maintenance cost saving of approximately £42M for the fleet. If a larger suspension stroke is allowed, more cost saving can be achieved. These results provide motivation to conduct detailed engineering design studies to further examine the trade-off between financial benefits and design complexity.

Toward a digital twin of a mid-speed marine engine: From detailed 1D engine model to real-time implementation on a target platform

System complexity is challenging for development of marine mid-speed engines when striving to meet increasingly stringent emission targets. Control-oriented modeling offers a solution, cutting calibration time and enabling robust control strategies. Simultaneously, real-time, physics-based engine models (digital twins) are emerging as they offer better predictive capability and scalability than typical mean-value, data-driven approaches. This study explored development of a control-oriented digital twin of a Wärtsilä 4L20 marine engine. Starting from a detailed one-dimensional model (GT-Suite), it explored reduction strategies toward a fast-running engine model (FRM), balancing the calculation speed and accuracy trade-off. Finally, the FRM was tested for real-time implementation on a target machine. Comprehensive experimental data from the 4L20 platform in the VEBIC Engine Laboratory provided the baseline for model calibration. Model calibration and validation covered four representative operating points and involved correlation of crank-angle, resolved in-cylinder pressures, thermal state at several locations of the engine air-path and relevant performance indicators. The results shed new light on the feasibility of digital twins in the marine engine domain. The obtained FRM was three times faster than real-time, while the accuracy loss was comfortably within the 5% tolerance levels for the governing outputs, including crank angle resolved in-cylinder pressure. The grid-resolved simulation was obtained with four times fewer flow components and internal discretization length of 100% and 150% of the cylinder bore for intake and exhaust components respectively. The balance between predictivity, accuracy and real-time surplus, was ultimately more favorable than in state of the art automotive applications and enables exploring further coupling with semi-predictive emission sub-models. The real-time capable FRM is considered applicable in hardware-in-the-loop simulation, and this application is scheduled in a follow-up project.

PENDAMPINGAN PENYUSUNAN DETAIL ENGINERING DESAIN (DED) PENATAAN KAWASAN PERMUKIMAN DI KECAMATAN TANJUNG

Based on Undang-undang no 1 Tahun 2011, The implementation of residential areas is carried out with the aim of realizing an area that functions as a residential environment and a place for activities that support a planned, comprehensive, integrated, and sustainable life and livelihood in accordance with the spatial plan. The purpose of this assistance in the preparation of Detail Engineering Design (DED) is to realize a plan that is in accordance with the required technical standards. This service activity begins with an understanding of the Slum issued by the Mayor of Kota Bima, then proceeds with conducting a site survey to see existing problems, and finally by carrying out Focus Group Discussions (FGD) and technical meetings offline and online. This Community activity produces a Detailed Engineering Design (DED) and a profile of the Sapaga residential area arrangement in Kota Bima which is the basis for planning regional planning in the area. In the preparation of Detail Engineering Design activities, the expected output includes 7 (seven) parameters for structuring slum areas, only during implementation activities, of course, there are still some adjustments related to field conditions.

ANALISA DAMPAK LALU LINTAS JEMBATAN MUSI VI KOTA PALEMBANG

Traffic impact analysis is one of the studies used to identify traffic impacts due to land use changes that result in the emergence of travel rise and pulls that will affect traffic performance on road sections. The purpose of traffic impact analysis Musi VI Bridge is to analyze the existing traffic conditions in the road network affected by the construction of the Musi VI Bridge, analyze the impact of the construction of the Musi VI Bridge, analyze the performance of the intersection. In the area opposite the Sultan Mansyur road towards Bukit Besar, at this time the process of proposing detail engineering desain widening the road. On the opposite side of the ulu road Faqih Usman - access road to road KH. Wahid Hasyim carried out further work and will be opened to the public.

Comparison of Semi-Empirical Noise Models with Flyover Measurements of Operating Aircraft

The contribution of the engine and the airframe to the total noise generated by an aircraft varies with the operating conditions. Semi-empirical models are able to account for such variations but require detailed engine and airframe data as input that is not readily available for most aircraft types and operations. This hinders the validation of these models through comparison between predictions and experimental data. This work investigates the sensitivity of semi-empirical models of engine and airframe noise to slight variations of the input data, representative of uncertainties in geometrical parameters and variability of the aircraft operating conditions during flyovers. In addition, the predictions are compared to measurements of A320, A330, and B777 landings and departures. This, together with the sensitivity analysis, indicates frequency regions where a mismatch between measurements and predictions exists. The deviation between predictions and measurements for landings can be partially explained by the underestimation of the sound pressure level of the higher harmonics of the fan. For takeoff, the models predict lower levels than measured. This is hypothesized to be associated with jet-installation noise, which is not accounted for in the semi-empirical models. The predicted spectra of the Airbus A320 and A330 were adjusted to account for jet installation noise, using levels available in the literature. This resulted in a better agreement between modeled and measured spectra at low frequencies.

Coiled Tubing Program Succeeds in Harsh-Environment Tight Gas Wells

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 209032, “Successfully Adapting and Overcoming Challenges for Coiled Tubing Applications in High-Pressure Sour Environments and Horizontal Unconventional Tight Gas Wells in UAE,” by Ole Sorensen, Yang Wu, and Didier Caillon, SPE, TotalEnergies, et al. The paper has not been peer reviewed. During the completion phase of four unconventional wells in the United Arab Emirates, a detailed engineering approach overcame challenges presented by extreme conditions of pressure, temperature, and a sour environment across long horizontal sections to carry out cleanout activities successfully. This operation, the first of its kind in the country for the operator, yielded lessons for design considerations and the execution process and recommendations for coiled tubing (CT) intervention in similar working environments. It also confirmed that 110,000-psi-yield-strength quench-and-tempered (Q&T) CT strings can be deployed safely in a high-pressure sour environment by implementing proper risk-mitigation strategies. Introduction The unconventional gas play (referred to as “A” in the complete paper) featured a reservoir pressure of nearly 13,000 psi and a bottomhole temperature of approximately 325°F. The environment was sour, with 5 mol% of hydrogen sulfide (H2S) and 5% carbon dioxide (CO2). The well’s architecture consisted of a 5½-in. monobore completion with cemented casing and horizontal sections ranging from 5,000 to 8,200 ft. The selected completion methodology was plug-and-perf, including up to 35 fracturing stages in a single well. Overview of CT Intervention Challenges The true vertical depth of the play was 12,600 ft on average, representing a maximum anticipated surface pressure (MASP) of 8,000 psi with the wellbore full of working fluid (8.34-lbm/gal slickwater) and a maximum potential wellhead pressure (MPWHP) of 11,300 psi with the wellbore full of gas. Also, partial pressures of H2S and CO2 exceeded 600 psi at bottomhole conditions, confirming that sour- and corrosive-service programs had to be implemented fully in this project. Convergence of MASP above 7,500 psi, CT dynamic pressure of greater than 11,000 psi, lateral length of up to 8,200 ft, and the sour and corrosive environment required a highly engineered approach on the design and selection of the CT string and configuration of the surface equipment.