Dynamic Source Research Articles

Effective Engineering Noise Control Strategies with the Stochastic Noise Mapping Simulation Method: A Case Study in Palm Oil Mill

Excessive sound levels pose a substantial risk to the hearing health of industrial workers. This study introduces a stochastic noise mapping technique to propose effective engineering control methods for noise mitigation in the palm oil industry. A case study conducted in a Malaysian palm oil mill employed data to predict the noise mapping and assess personal noise exposure levels of workers. Results showed that 29.6% of the area fell within the high-risk zone, with 28.1% in the extremely high-risk zone. Personal noise monitoring revealed that many workers were exposed to excessive noise, with a maximum time-weighted average sound level of 99.2 dBA among the worker groups. Despite the provision of protective equipment by management, regular usage of hearing protectors during work shifts was lacking. To reduce noise levels, two engineering control methods were proposed: erecting noise barriers around high noise emission sources and limiting the maximum sound power to 110 dBA for dynamic noise sources. Implementing these controls resulted in a 10.9% decrease in the extremely high-risk zone and a 17.8% decrease in the high-risk zone. These findings hold significance as they can guide the implementation of noise monitoring practices and engineering noise control in the industry.

Liquid biopsy for lung cancer: A cross section on the diagnostic routine experience of a referral Italian institution

BackgroundLung cancer is the leading cause of cancer death worldwide. Over the last decade, molecular testing of a growing number of predictive biomarkers has become mandatory in the management of NSCLC patients. However, a major obstacle in routine clinical practice is the scant quantity of available tissue specimens obtainable from advanced stage of NSCLC patients. Thus, liquid biopsy, mostly involving blood sampling, has now been integrated in routine diagnostic practice. However, although liquid biopsies constitute a versatile, compliant, and dynamic source of nucleic acids, many of the current testing approaches pose few technical challenges. Here, to validate the feasibility of implementing NGS-based liquid biopsy approaches in routine diagnostic practice, we overviewed the NGS molecular data generated by our in-house narrow gene panel on plasma samples from real-world NSCLC patients. MethodsOur Institution received testing request on liquid biopsy samples from peripheral institutions not equipped to internally analyze liquid biopsy samples. Molecular data from NSCLC patients following oncological requested for clinically approved plasma-based biomarkers evaluated in a diagnostic routine setting from January 2020 to September 2022 were retrieved from our institutional archive. A customized NGS panel integrated with an optimized bioinformatic pipeline was adopted. ResultsOverall, a total of n = 185 cases were retrieved. Of note, 103 (55.7 %) and 82 (44.3 %) patients were analyzed at basal setting and after resistance to first line TKI administration, respectively. Moreover, 31 out of 185 (16.7 %) cases reveled EGFR clinically relevant alterations. In particular, 6 out of 31 (19.3 %) and 25 out 31 (80.7 %) EGFR mutated patients were tested in basal setting and after first or second line TKIs progression. In addition, exon 20 p.T790 M mutation was also detected in 12 out of 25 (48.0 %) EGFR concomitant mutated cases. Moreover, KRAS hot spot mutations were found in 24 out of 185 (13.0 %) cases. Among them, exon 2 p.G12C clinically relevant mutations were observed in 8 out 24 cases (33.3 %). ConclusionsThis review highlights the technical suitability of an NGS-based liquid biopsy system for the analysis of clinically relevant mutations in NSCLC patients.

Pengaruh Ketangkasan Organisasi Untuk Mencapai Kesuksesan Digital Transformasi

The rapid development of digital technology and its application throughout business organizations makes digital transformation a source of sustainable business dynamics. Previous research has investigated several factors that influence digital transformation, but there is little research on the impact of organizational agility on digital transformation in organizations. To fill this gap, this research aims to investigate how organizational agility and the factors that influence organizational agility influence the success of digital transformation in companies. A survey study was conducted to empirically test the model. Data was collected from 158 private and BUMN employees in Indonesia. The findings show that organizational agility has a significant effect on digital transformation and the speed of response to market demands is an important predictor of organizational agility.

Stochastic simulation of earthquake ground motions based on improved finite-fault model

In the seismic reliability analysis of engineering structures, it is often necessary to adopt stochastic ground motions as inputs. However, the current methods used to generate stochastic samples, such as the spectral representation method, the spectral transfer method, the dynamic source method, the physical source method, and the comprehensive method, etc., are not very convincing since they do not contain the complete information of seismic occurrence and propagation. In this study, an improved finite-fault model for stochastic simulation of ground motions is proposed. Compared to existing stochastic finite-fault model, the improved model considers the propagation law of phase spectrum, local site effect, and the impact of wave velocity on the arrival time of seismic waves. Besides, identification and statistics of model parameters are carried out based on ground motion records. Reasonable samples of stochastic ground motions are then obtained. In addition, parameter sensitivity analysis is conducted to determine critical random variables, which reduces the complexity of stochastic simulation. Simulation results are compared with recorded accelerograms from the 1999 Chi-Chi earthquake. It is shown that the improved stochastic finite-fault model is reliable, and the acceleration response spectra of simulated samples are consistent with those of station records collected at various site classes and the design spectra.

Numerical analysis of topology-optimized cold plates for thermal management of battery packs

Thermal management is important for battery packs and liquid cooling is one method which gains more attentions. However, for the battery cold plate, ensuring the uniformity of the battery temperature and reducing the pressure drop is the issue that needs to be addressed. In order to solve this problem, this paper uses the method of topology optimization to design two novel cold plates (TOPA and TOPB)with different functional focuses. An experimentally derived dynamic simulated heat source is used to model the performance of a cold plate in combination with a high-capacity battery. Then their performance are compared with that of conventional cold plates(RP and SP) by numerical simulation. The results indicate that these new cold plates are able to guarantee the dual requirements of temperature uniformity and low flow resistance. Under the condition of 0.1 m/s inlet velocity, TOPA and TOPB have 1.6 % and 1.7 % lower maximum battery temperatures compared to RP, TOPA and TOPB have 46.7 % and 42.3 % better battery temperature uniformity compared to SP cold plate, and both have about 70 % lower pressure drop than SP. Appropriately increasing the inlet velocity of the cold plate also reduces the maximum battery temperature and temperature difference. Moreover, the values of pressure drops for TOPA and TOPB are very close to RP under all inlet velocity conditions. At the same input power, the heat transfer coefficient of the TOPA cold plate is 69 % and 33 % higher than that of RP and SP cold plates, respectively. As a result, this new cold plate is more suitable for use in BTMS than conventional cold plates.

Trust-Based Routing Selection Policy on Mobile Ad-Hoc Network Using Aodv Routing Protocol

This study presents an enhanced Ad-hoc On-demand Distance Vector (AODV) routing protocol, termed Proposed_TAODV, designed to improve security in Mobile Ad-Hoc Networks (MANETs) of 150 nodes by incorporating trust-based mechanisms. Through a comprehensive simulation, the Proposed_TAODV is evaluated against existing AODV and Dynamic Source Routing (DSR) protocols under conditions of increasing malicious node presence. The results reveal that Proposed_TAODV maintains a higher Packet Delivery Ratio, experiences lower Average End-to-End Delay, and achieves greater Throughput compared to the benchmarks, indicating its superior performance and robustness. The integration of Direct Trust Evaluation, Indirect Trust Evaluation, and Trust Aggregation methods into the AODV protocol clearly enhances the MANET's resilience to security threats, establishing the Proposed_TAODV as a promising approach for securing MANETs against various forms of attacks and network disruptions.

Experimental and numerical simulation of three-point bending fracture of brittle materials with inverted T-shaped obstacle cracks

In rock materials, the interaction and coalescence of three-dimensional internal cracks play a fundamental role in material failure and instability. This study focused on the generation of three-dimensional internal cracks inside specimens using the three-dimensional internal laser-engraved crack (3D-ILC) method, without causing surface damage. Experimental and numerical investigations were conducted to examine the fracture behavior of brittle solid materials with and without obstacles during three-point bending tests. The experimental results revealed that obstacle cracks positioned horizontally in an inverted T configuration exhibited a shielding effect on the vertical cracks, resulting in reduced propagation velocity and decreased curvature at the lower tip of the vertical cracks. Crack initiation and propagation were promoted in the presence of obstacle cracks, forming distinct fracture patterns, such as pear-shaped and hook-shaped configurations. While the overall failure mode of the specimens was not significantly altered by the presence of obstacle cracks, dynamic fracture dual sources, and new Mode III cracks were observed on the fracture surfaces. The 3D-ILC method provided an effective means for studying the integration and penetration of pre-existing three-dimensional internal cracks. The findings of this study contribute to the theoretical understanding of fracture propagation through obstacles in brittle materials and provide a basis for further investigations using physical experiments.

WALS: A Lightweight Stateless Label Switching Framework Based on Prime Theorem for MANETs

This article proposes an innovative unicast/multicast unified, cross-layer, and control/user-plane splitting forwarding method, called Wireless Arithmetic Label Switching (WALS), for mobile ad-hoc networks (MANETs). The WALS is based on a stateless approach: an arithmetic source-routed label is processed by the source and intermediate nodes without table lookup, causing lower protocol overheads and forwarding latency than the conventional stateless unicast/multicast routing protocols such as the Dynamic Source Routing (DSR) and the Differential Destination Multicast (DDM) respectively. Different from conventional unicasting/multicasting designs demanding distinct routing protocol stacks, the WALS requires a unified protocol stack, avoiding the need to distinguish unicast and multicast frames, thus simplifying the design of MANET devices. Mathematical analysis indicates that the WALS is highly scalable for both the network sizes and the number of multicast groups. Simulation results reveal that WALS effectively performs network scalability and the required overhead for the unicast and multicast capabilities. Additionally, WALS achieves superior to the other three state-of-the-art competitive multicast routing methods including DVMRP, ODMRP, and MAODV on the performance of the packet processing latency and packet delivery ratio. As a result, the WALS can significantly enable the employment and management of integrated unicast and multicast services for MANETs.

A large-scale empirical investigation of specialization in criminal career

We use a comprehensive longitudinal dataset on criminal acts over 6 years in a European country to study specialization in criminal careers. We present a method to cluster crime categories by their relative co-occurrence within criminal careers, deriving a natural, data-based taxonomy of criminal specialization. Defining specialists as active criminals who stay within one category of offending behavior, we study their socio-demographic attributes, geographic range, and positions in their collaboration networks relative to their generalist counterparts. Compared to generalists, specialists tend to be older, are more likely to be women, operate within a smaller geographic range, and collaborate in smaller, more tightly-knit local networks. We observe that specialists are more intensely embedded in criminal networks, suggesting a potential source of self-reinforcing dynamics in criminal careers.

Computational Modeling with Phantom-Tissue Validation of Gold-Nanorod-Enhanced Laser Ablation of Prostate Cancers

Abstract The purpose of this study was to develop a computational model for the laser ablation (LA) of prostate cancer, enhanced by gold-nanorods (GNRs) in a phantom-tissue system, and to explore the effect of GNRs on the ablation zone. A prostate biomimetic tissue (PBT) was prepared with different volume fractions of GNRs. Specifically, the computational model was built by considering the change of light properties of PBTs with and without GNRs and introducing the dynamic heat source determined by porcine liver carbonization, reported elsewhere. The computational model was then validated by comparing the simulation and the ex vivo LA experiment in terms of three performance indexes, namely, (i) the spatiotemporal temperature distribution, (ii) ablation zone, and (iii) carbonization zone, with the three volume fractions of GNRs in the PBT model, as mentioned above. Except for minor discrepancies found in the carbonization zone, the proposed model agrees with the experimental data. The effect of GNRs on LA was explored with the help of the model, and nine combinations of the laser powers and the volume fractions of GNRs were tested. The result shows that the ablation zone increases with the increase in the volume fraction of GNRs for all three laser powers used. Two conclusions can be drawn: (1) loading GNRs into the tissues may increase the ablation zone of LA, and (2) the proposed computational model is a reliable tool for predicting the spatiotemporal temperature distribution and the ablation zone of the GNR-enhanced LA.

Metric f(R) gravity with dynamical dark energy as a scenario for the Hubble tension

ABSTRACT We introduce a theoretical framework to interpret the Hubble tension, based on the combination of a metric f(R) gravity with a dynamical dark energy contribution. The modified gravity provides the non-minimally coupled scalar field responsible for the proper scaling of the Hubble constant, in order to accommodate for the local SNIa pantheon+ data and Planck measurements. The dynamical dark energy source, which exhibits a phantom divide line separating the low redshift quintessence regime (−1 < w < −1/3) from the phantom contribution (w < −1) in the early Universe, guarantees the absence of tachyonic instabilities at low redshift. The resulting H0(z) profile rapidly approaches the Planck value, with a plateau behaviour for z ≳ 5. In this scenario, the Hubble tension emerges as a low redshift effect, which can be in principle tested by comparing SNIa predictions with far sources, like QUASARS and gamma ray bursts.

Rendering Dynamic Source Motion in Surface Haptics via Wave Focusing.

Emerging surface haptic technologies can display localized haptic feedback anywhere on a touch surface by focusing mechanical waves generated via sparse arrays of actuators. However, rendering complex haptic scenes with such displays is challenging due to the infinite number of physical degrees of freedom intrinsic to such continuum mechanical systems. Here, we present computational focusing methods for rendering dynamic tactile sources. They can be applied to a variety of surface haptic devices and media, including those that exploit flexural waves in thin plates and solid waves in elastic media. We describe an efficient rendering technique based on time-reversal of waves emitted from a moving source and motion path discretization. We combine these with intensity regularization methods that reduce focusing artifacts, improve power output, and increase dynamic range. We demonstrate the utility of this approach in experiments with a surface display that uses elastic wave focusing to render dynamic sources, achieving millimeter-scale resolution in experiments. Results of a behavioral experiment show that participants could readily feel and interpret rendered source motion, attaining 99% accuracy across a wide range of motion speeds.

End to end delay distribution analysis and interference aware high throughput for Wireless Mesh Networks

The wireless mesh network is an innovative and efficient wireless communication approach with immense potential to transform future wireless networks. This cutting-edge wireless technology provides a wide range of wireless services for personal, local, campus, and metropolitan environments. The wireless mesh network consists of a cluster of mobile wireless nodes that can dynamically and instantaneously create random and temporary network topologies, forming a wireless ad-hoc network. Ad hoc wireless networks are particularly advantageous due to their cost-effectiveness and ease of deployment. In order to further optimize the performance of ad-hoc networks, different routing algorithms such as Ad-hoc On-Demand Distance Vector Routing (AODV), Dynamic Source Routing Algorithm (DSR) and Destination Sequenced Distance Vector (DSDV) have been thoroughly researched via simulation.

Non-Contact Impact Source Localization in Composite Symmetry Panels Based on A0 Mode of Lamb Waves

Traditional methods for detecting damage in engineering structures often use offline static damage detection. To enable the real-time and precise identification of dynamic damage while maintaining symmetry in engineering structures, this study primarily concentrates on isotropic plate structures widely employed in engineering. Moreover, fiberglass board composite plates were opted as a specific research object. By utilizing the weak S0 mode signals generated by low-frequency ultrasonic Lamb waves, the non-stationary A0 wave signals in the composite symmetry plate structure are collected using the non-contact SLDV (Scanning Laser Doppler Vibrometer) technique. The frequency characteristic parameters in the vibration signals are obtained through HHT (Hilbert–Huang Transform) analysis, followed by filtering and noise reduction. Finally, the circular trajectory intersection method is employed to accurately locate dynamic damage sources in plate structures with different material properties, thereby validating the positioning effect of contact sensors in detecting impacts caused by random impulses.

Stochastic stability analysis of legged locomotion using unscented transformation

In this manuscript, we present a novel method for estimating the stochastic stability characteristics of metastable legged systems using the unscented transformation. Prior methods for stability analysis in such systems often required high-dimensional state space discretization and a broad set of initial conditions, resulting in significant computational complexity. Our approach aims to alleviate this issue by reducing the dimensionality of the system and utilizing the unscented transformation to estimate the output distribution. This technique allows us to account for multiple sources of uncertainty and high-dimensional system dynamics, while leveraging prior knowledge of noise statistics to inform the selection of initial conditions for experiments. As a result, our method enables the efficient assessment of controller performance and analysis of parametric dependencies with fewer experiments. To demonstrate the efficacy of our proposed method, we apply it to the analysis of a one-dimensional hopper and an underactuated bipedal walking simulation with a hybrid zero dynamics controller.

Total BIM on the construction site: a dynamic single source of information

Digital technologies are rapidly transforming the construction industry, offering new opportunities to improve site work performance. Traditionally, site workers take information from static construction documents such as 2D paper drawings. However, in the Nordic region, a dynamic approach known as Total BIM has gained interest. Total BIM is a model-based approach to construction where BIM replaces 2D drawings as the contractual and legally binding construction document, and site workers use production-oriented, cloud-based BIM, on mobile devices to extract construction information. By having a dynamic single source of information, site workers face new demands as they independently extract construction information directly from BIM. This paper investigates the impact of Total BIM on site work methods through four real-life case studies, site visits, workshops, seminars and semi-structured interviews. The findings indicated that Total BIM provided site workers with a more dynamic construction process where the mobile BIM-viewer software became a central communication and management platform. Key digital Total BIM features were investigated that site workers used to perform new work methods, including measuring, filtering, visualizing, communicating, checklists, and requests for information. By using Total BIM instead of static 2D drawings, site workers interacted dynamically with BIM on mobile devices, changing the process of how work was implemented on the construction site. The practical implications of these findings can be used to support the on-site implementation and strategy work of Total BIM. Furthermore, this paper contributes practical concrete examples of on-site Total BIM use and addresses issues commonly found in state-of-the-art BIM projects.

Dynamic Source Distribution and Emission Inventory of a Persistent, Mobile, and Toxic (PMT) Substance, Melamine, in China.

Persistent, mobile, and toxic (PMT) substances are affecting the safety of drinking water and are threatening the environment and human health. Many PMT substances are used in industrial processing or consumer products, but their sources and emissions mostly remain unclear. This study presents a long-term source distribution and emission estimation of melamine, a high-production-volume PMT substance of emerging global concern. The results indicate that in China, approximately 1858.7 kilotonnes (kt) of melamine were released into the water (∼58.9%), air (∼27.0%), and soil systems (∼14.1%) between 1995 and 2020, mainly from its production and use in the decorative panels, textiles, and paper industries. The textile and paper industries have the highest emission-to-consumption ratios, with more than 90% emissions per unit consumption. Sewage treatment plants are the largest source of melamine in the environment for the time being, but in-use products and their wastes will serve as significant melamine sources in the future. The study prompts priority action to control the risk of PMT substances internationally.

Heat transfer characteristics of phase change materials in double-layer packed bed under dynamic thermal boundary

Dynamic thermal boundary conditions have a significant impact on the thermal storage performance of phase change materials (PCMs) in packed beds. In this paper, an unsteady numerical heat transfer model of a double-layer packed bed is established and verified. The heat storage characteristics of the four PCM combination schemes are calculated and compared, and the sinusoidal wave heat source is used as an input parameter to study the influence of wave amplitude and period changes on the thermal performance of the system. The study shows that when the volume ratio of PCM 1 to PCM 2 is 1/3:2/3, the melting time is shorter and the heat storage rate is faster. The long-period fluctuation can significantly shorten the melting time and improve thermal performance. When the period is 120 min, the melting time is shortened by about 15.2 % compared with the steady state, and the heat storage rate is increased by 19.6 %. The larger the amplitude of the heat source, the stronger the promotion effect on melting. When the amplitude is 16 °C, the melting time is shortened by about 17.7 % compared with the steady state, and the heat storage rate is increased by 16.7 %. The research results can provide some reference for the design of a double-layer packed bed under the dynamic heat source.

Assessment of kerogen types and source rock potential of Lower Jurassic successions in the Mandawa Basin, SE Tanzania

Variability in organic matter types and quality of source rock intervals across evolving rift-basins has been the focus of previous studies, which have shown that due to dynamic sedimentary regimes and water depths such source intervals occur sporadically and restricted to specific stratigraphic horizons. Such heterogeneous settings require detailed geochemical analysis to document variations in source quality. This study presents a comprehensive geochemical analysis of source rock intervals in Lower Jurassic successions (Mbuo, Nondwa and Mihambia Formations) in the Mandawa Basin, on-shore Tanzania, in order to constrain organic matter types and quality. Organic matter richness was measured by Total Organic Carbon (TOC) analysis, while quality and thermal maturity of organic matter was assessed by programmed pyrolysis, complemented by organic carbon isotope analysis (δ13Corg) of sediment samples collected from outcrops, cores, and cuttings samples. TOC and programmed pyrolysis datasets from existing literature were synthesized in this study to better understand organic matter quality and thermal maturity evolution on regional scale. These data were examined in relation to paleogeography to gain insight into the factors regulating the distribution of organic matter quality within the Mandawa Basin.Average TOC contents in Lower Jurassic sediments fluctuate from 0.31 to 4.83 wt% with an average of 1.4 wt%, whereas, kerogen yield (S2) and hydrogen index (HI) remain generally low, with values ranging from 0.01 to 8.6 (mg HC/g rock) with an average (0.92 mg HC/g rock) as well as from 2 to 233 (mg HC/g TOC) with an average of 46 (mg HC/g TOC), respectively. Organic matter is composed mainly of type III (gas prone) to IV (inert) kerogens with lesser admixture of type II-III kerogen (oil-gas prone), which have been deeply buried and undergone a wider range of thermal diagenesis, from early to overmature stage. The δ13Corg isotopic composition of organic matter is consistent with kerogen typing, indicating terrestrial organic matter with a heavier signature during sea level low stands. Upon marine incursions δ13Corg shifts to isotopically more depleted marine organic matter. This implies that the investigated source intervals have poor to fair source potential. Only a few intervals of limited thickness in the Upper Mbuo, Nondwa, and Mihambia Formations of the Mita Gamma-1 and East Lika-1 wells, as well as in the Lower Mbuo Formation in the Mbuo-1 well, have been locally enriched. The enrichment is attributed to periodic marine ingressions that have persisted since the Pliensbachian period and suggests the presence of oil generation potential.A comparison of TOC and programmed pyrolysis borehole data from this study to those compiled from literature in a paleogeographical context reveals high spatial variability. The southeastern and northwestern parts of the study area have the highest source potential, indicating high organic matter productivity in the dysoxic to anoxic water column, which promoted the preservation of organic matter. In contrast, the eastern and western parts generally show low source potential, indicating degraded organic matter and significant terrestrial influxes from emergent land that were deposited in shallow, mixed oxygenated water with low to moderate organic matter productivity.

Outstanding glucose sensing properties of N-doped carbon nanotubes boosted by Co(II) and Cu(II) ions in alkaline electrolytes

Electrochemical glucose detection co-catalyzed by bimetallic ions is carried out by introducing Co(II) and Cu(II) into the alkaline solution. The technique avoids the complicated electrode design and catalyst poisoning. By using nitrogen-doped carbon nanotubes (NCNT) loaded on carbon cloth (CC) as the working electrode, the bimetal co-catalytic system achieves a sensitivity of 6,909 mA M−1 cm−2, a detection limit of 0.4 μM (S/N = 3), as well as good selectivity and stability. By performing systematic electrochemical and structural analysis, the mechanism of Co(II) and Cu(II) co-catalysis for glucose detection in the solution is elucidated. Co(II) supplies the dynamic reaction sites and source of active intermediate (CoOOH), while Cu(II) promotes the formation of CoOOH. The results provide mechanistic insights into bimetal co-catalysis of glucose detection and other electrochemical reactions.