bluuebunny/crossref_metadata_2025 huggingface dataset:
Circuit modelling and validating a capacitively loaded implantable antenna with its sensitivity analysis for biomedical applications
Authors: Kaur Sukhpreet , Kaur Jaswinder , Khanna Rajesh
Published: August 2024

This paper presents a flexible and capacitively loaded implantable antenna with its sensitivity analysis for biomedical applications. The proposed antenna is designed to operate within the ISM (Industrial, Scientific, and Medical) band, which ranges from 2.4 to 2.48 GHz. The overall dimensions of an antenna are 8 × 8 × 0.25 mm3. The substrate material FR-4 is utilised with a dielectric constant (ε
r) 4.4, loss tangent (δ) 0.0022 and a thickness of 0.25 mm for the proposed antenna. An ultra-flexible superstrate material, Parylene C, is used with a thickness of 40 microns on both sides of an antenna to avoid direct contact of metallization with human tissue. Further, the proposed antenna is initially implanted inside a four-layer cubic (FLC) phantom, and then its parameters are validated using the CST Hugo voxel model. The simulated bandwidth of an antenna is 28.16 %, whereas measured bandwidths are 32.25 % inside the tissue-mimicking phantom and 64 % inside minced pork. Moreover, assessing the specific absorption rate (SAR) in a realistic model ensures patient safety by following the guidelines outlined in C95.1–1999 for 1g and 10g of tissue. The simulated and measured results are in close agreement, making the designed antenna appropriate for biomedical applications.
Dynamic potential stochastic resonance for weak signal detection
Authors: Zong Ping , An Ran , Wang Hongyu , He Jiaming , Zhang Chi
Published: August 2024

To suppress the low-frequency interference noise, a dynamic potential stochastic resonance (DPSR) model is proposed in this paper for weak signal detection. The DPSR model introduces a single dynamic parameter k that simplifies parameter optimization. Its dynamic potential function can adaptively adjust to match noisy input signals. This model provides a new nonlinear model for triggering the SR phenomenon. Experimental results indicate that compared to the traditional methods that rely on clear interference frequency distributions to filter low-frequency components directly, the SR model offers greater flexibility and convenience. Unlike classical SR models, the proposed DPSR model demonstrates a 1.5 dB improvement in output performance for suppressing low-frequency interference. Therefore, the DPSR model not only robustly suppresses interference but also effectively enhances and detects characteristic signals in variant-noise environments. Application to sea trial signals highlights the superior performance of the DPSR model in significantly reducing low-frequency interference and improving target signal recognizability compared to other models.
Non-Gaussianity consistency relations and their consequences for the peaks
Authors: Namjoo Mohammad Hossein , Nikbakht Bahar
Published: August 2024

Strong deviations from scale invariance and the appearance of high peaks in the primordial power spectrum have been extensively studied for generating primordial black holes (PBHs) or gravitational waves (GWs). It is also well-known that the effect of non-linearities can be significant in both phenomena. In this paper, we advocate the existence of a general single-field consistency relation that relates the amplitude of non-Gaussianity in the squeezed limit f
NL to the power spectrum and remains valid when almost all other consistency relations are violated. In particular, it is suitable for studying scenarios where scale invariance is strongly violated.
We discuss the general and model-independent consequences of the consistency relation on the behavior of f
NL at different scales.
Specifically, we study the size, sign and slope of f
NL at the scales where the power spectrum peaks and argue that generally the peaks of f
NL and the power spectrum occur at different scales.
As an implication of our results, we argue that non-linearities can shift or extend the range of scales responsible for the production of PBHs or GWs, relative to the window as determined by the largest peak of the power spectrum, and may also open up new windows for both phenomena.
Application of drone technology in power grid engineering
Authors: Zhai Xiaomeng , Shao Mengyu , Cang Min , Cheng Xi , Wu Shuang , Wang Jingyi
Published: August 2024

With the dynamic adjustments in eco-control zones, spatial layouts can be further optimized, but this has brought some challenges to the planning and construction of power grid projects. Utilizing drones and related technologies, it is possible to conduct surveys of eco-control zones with clear boundaries and unclear boundaries, which is beneficial for early risk avoidance in power grid projects. The results indicate that the use of orthophoto and oblique photography can effectively measure the boundaries of control areas and classify the ecological types within the research area. Maximizing the use of drone surveying technology can effectively identify control area boundaries, but attention must be paid to the factors affecting drone operations to prevent excessive measurement errors and reduce the accuracy of control area identification.
Research on the performance and application of waterproofing materials in tunnel engineering
Authors: He Hongbo
Published: August 2024

With the rapid development of highway transportation, the volume and construction difficulty of tunnel engineering have been increasing year by yea. Many engineering problems are difficult to solve, among which leakage is one of them. Tunnel waterproofing materials are an important component of controlling leakage and ensuring the safety and reliability of tunnel engineering. This paper provides the types, characteristics, and applications of tunnel waterproofing materials in tunnel engineering. The classification of tunnel waterproofing materials is introduced, including grouting materials, geotextile materials, and waterproofing board materials. Then, the characteristics of each type of material are elaborated in detail, including durability, constructability, and environmental friendliness. Finally, combined with actual engineering cases, the application of these tunnel waterproofing materials in tunnel engineering is discussed. This paper aims to provide a reference for the design and construction of tunnel engineering, and to provide a theoretical and practical basis for the research and application of tunnel waterproofing materials.
Polymer-based solid/semi-solid electrolytes in lithium ion batteries
Authors: Sun Bangwei
Published: August 2024

The inception of lithium-ion batteries with liquid electrolytes can be traced back to the early 1980s. Nevertheless, the utilization of liquid electrolytes has many drawbacks, including its susceptibility to combustion, limited energy density, and very brief operational lifespan. Consequently, there is currently a concerted effort to substitute liquid electrolytes with solid compounds. This study investigates the electrochemical and mechanical features of solid/semi-solid electrolytes used in lithium ion batteries (LIBs) as well as their performance relative to conventional liquid electrolytes, with LIBs having unique challenges related to high flammability, electrochemical instability, and low mechanical stability posed by conventional liquid electrolytes versus solid polymer electrolytes (SPEs) which provide greater safety, mechanical stability but lower ionic conductivity than liquid counterparts. SPEs offer better safety but lack sufficient ionic conductivity which limits their potential. In order to overcome these obstacles, the implementation of gel-based and composite solid and semi-solid electrolytes is proposed as a means to improve ionic conductivity, electrochemical stability, and mechanical stability. The study suggests that a focus should be placed on solid composite electrolytes as they possess higher mechanical stability, which contributes to improved safety. Additionally, these electrolytes exhibit enhanced ionic conductivity within the range of 10−4 to 10−2 S/cm, hence enhancing the performance of LIBs.
A study on yield calculation method using suspension power chart in beam pumping systems
Authors: Jiang Minzheng , Li Jiawei , Chen Changhe , Liu Geng
Published: August 2024

Accurate production prediction plays a crucial role in well fault diagnosis and parameter optimization, significantly contributing to the advancement of oilfield digital construction. This paper focuses on the dynamic analysis of beam pumping machines to establish a calculation model for the power diagram of rod pumping systems. The solution involves employing the finite difference method and Fourier series method, facilitating the transition from the suspension point work diagram to the pump work diagram. The effective stroke of the plunger is determined by analyzing the opening and closing points of the Ver using the maximum curvature analysis method. Subsequently, the leakage and volume coefficients are derived by integrating on-site production data, culminating in the realization of an oil well production calculation method based on the suspension work diagram. The compilation of the pump power chart and oil well production calculation program was executed using QT 6.2.3. Comparative analysis with measured production data revealed an average accuracy of 90.05% using the finite difference method, surpassing the performance of the Fourier series algorithm. The established model not only offers a reliable means of predicting production but also provides valuable technical support for the digital and intelligent applications within the oilfield.
A review of coordinated multi-robot exploration
Authors: Hu Xinyu , Pei Haoyu
Published: August 2024

A multiple robots system provides advantages over a single robot when it comes to exploring an unfamiliar area. Due to its applications in localization and mapping, search and rescue, etc. This technology has attracted a lot of study interest. The main challenge is properly distributing target points among several robots so that they can each investigate a separate section of the environment simultaneously and ensure the shortest possible total exploration time. However, more work still needs to be done to incorporate research issues in a real setting, such as how to eliminate duplicate exploration areas by giving robots multiple target locations or how to avoid unanticipated barriers in new situations. The allocation algorithms, motion planning techniques, and exploration strategies used in multi-robot collaboration (CME) are reviewed in this paper. Additionally, it provides an explanation of the methods research teams employ to optimize traditional whale optimization algorithm (WOA), how they enhance exploration performance and speed, and a comparative analysis of these methods. We also discussed a cooperative exploration method based on dynamic Voronoi partitioning. However, we also need some obstacle avoidance algorithms to help understand the gaps and issues that will need to be solved in the upcoming years, namely how to handle unexpected impediments in unfamiliar surroundings. Lastly, a summary of potential future lines of inquiry and uses is given.
Non-destructive testing method of concrete based on piezoelectric sensor
Authors: Heng Liying
Published: August 2024

This paper reviews the research and development of non-destructive techniques for monitoring concrete in the past. Active detection techniques, particularly Electro-Mechanical Impedance method and Wave Propagation method have been demonstrated to be effective in monitoring the concrete process. Electro-Mechanical Impedance method detects internal structural damage by analyzing the vibration characteristics of the structure by combining a piezoelectric transducer with the system to be measured. Compared to the Electro-Mechanical Impedance method, the fluctuation method uses two or more transducers, with one serving as an exciter to actively excite the signal. In contrast, the others form an array to receive the stress wave signal. This method offers several advantages, including the absence of dependence on an impedance meter and passive excitation, a simple operating principle, high response frequency, and high immunity to interference. In this work, the research status and progress in the field of non-destructive testing (NDT) of concrete are combined to summarize the results and refine the methodology of the research on the evaluation of concrete material properties and identification of structural damage; based on this, the bottlenecks, research difficulties and difficulties in the field are further outlined, and finally, the research outlook of NDT of concrete in response to these limitations is put forward.
A review of the effect of temperature on the performance of viscoelastic dampers
Authors: Liu Yijie
Published: August 2024

This paper introduces structure and characteristics of viscoelastic damper and analyses the effect of temperature on its performance. Elastic damper is a kind of damping device which mainly relies on the hysteretic energy dissipation characteristic of viscoelastic material to realize the purpose of structural shock absorption. It is widely used in vibration control of mechanical equipment and building structures. However, in the application and research of viscoelastic dampers, it is found that temperature has a significant effect on their performance. This paper first introduces the basic concept of viscoelastic dampers, and points out that there are few papers discussing the effect of temperature on viscoelastic dampers in recent years. In the second part of this paper, the structural composition and characteristics of viscoelastic dampers and viscoelastic materials are introduced. After that, this paper introduces the influence of temperature on the performance of viscoelastic damper from various aspects, and then focuses on the analysis of the influence of temperature on the energy dissipation performance of the damper.
Advantages, manufacturing processes and challenges of FinFET technology
Authors: Zhou Jingfeng
Published: August 2024

As an emerging cutting-edge integrated circuit technology, Fin Field Effect Transistor (FinFET) has not only successfully broken through the limitations of the 22nm node since its development in 1998, but it still maintains considerable vitality and is developing into smaller sizes. As an improvement over traditional MOSFET technology, FinFET offers many technical advantages, which practically solve the challenges encountered by traditional MOSFET. The FinFET process technology is incompatible with planar MOSFET process technology. Moreover, since the development of Finfet technology, there have been many technical challenges. The first half of this article mainly introduces the differences and advantages between FinFET and traditional Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), and briefly outlines its manufacturing process. The second half explains the challenges and hopes on the development path of FinFET technology. I believe this article can provide a reference for integrated circuit designers when understanding FinFET technology, and provide guidance and reference for beginners.
Preparation and research progress in biomedical field of LDHs
Authors: Wen Luning
Published: August 2024

Layered Double Hydroxides (LDHs) are layered compounds composed of a positively charged main layer and interlayer anion assembled by non-covalent bond interaction. The chemical composition of the main lamella in LDHs can be modulated, as can the type and quantity of interlayer anions so that the particle size and distribution of its intercalated assembly can be regulated. Because of its unique physical and chemical properties, it can treat or repair the human body by acting as a drug carrier, introducing antibacterial ions, and as a therapeutic material. Therefore, it has great application prospects in the biomedical field. This paper will briefly describe the preparation method of LDHs and give an example of a specific process for LDHs. After that, this paper will review the application of LDHs in tumor treatment, antibacterial effect, and bone repair and summarize the progress of the application of LDHs in the biomedical field, as well as the opportunities and challenges faced.
A study on a low input current ripple high voltage gain cuk converter
Authors: Liu Liyou , Chen Yongqiang , Liao Hongsheng , He Jingping
Published: August 2024

In the realms of photovoltaic power generation and fuel cells, the application of traditional DC-DC boost converters faces significant constraints due to insufficient gain and pronounced input current ripple. This paper presents a design for a Cuk converter with low input current ripple and high voltage gain based on the conventional Cuk topology. The design incorporates a passive ripple circuit and a coat circuit. The operational principles of the converter are analyzed, followed by the construction of a simulation model in PSIM. Simulation results not only validate the theoretical analysis but also affirm the feasibility of the proposed converter.
An elliptical dual-band antenna with crescent slot for 5G mmWave applications
Authors: Wang Lingyan , Li Huaqing , Shi Yawei , Chen Menggang , Li Chuandong , Wang Huiwei , Zheng Lifeng
Published: August 2024

This paper proposes a new elliptical dual-band antenna with a crescent slot with the advantages of compactness, lightweightness, low cost, and easy installation for 5G mmWave applications. The radiating element is obtained by Boolean manipulation of three ellipses of unequal length to short axis ratio, the resulting crescent slot defining its dual-band characteristics. The -10 dB impedance bandwidth of 23.8—31.6 GHz at 28 GHz and a bandwidth range of 36.8—40.6 GHz at 38 GHz are achieved, completely covering the currently applicable n257, n258, n260 and n261 mmWave bands and filtering out the unlicensed 31—36 GHz band. Dimensions of the single element are 10 mm by 7 mm. In addition, to reduce the interference caused by atmospheric attenuation, a conventional feeder network is combined with the designed antenna element to form a 1 × 4 line array to improve the gain. The antenna array with total dimensions of 20 × 25 mm2 is modeled in 0.254 mm thick Rogers 5880 substrate. As a result of the array configuration, 10.4 dBi gain and a 95% radiation efficiency are achieved in the 28 GHz band. Meanwhile, at the 38GHz band, the gain is 10.4 dBi and the radiation efficiency is 95%. The proposed antenna meets the 5G communication requirements well and can be a better candidate in the mmWave band range.
Research on channel modeling technology of visible light communication system based on the ray tracing method
Authors: Gu Zhiming , Yang Junhong , Wang Pengliang
Published: August 2024

Visible Light Communication (VLC) is a new mode that combines lighting and communication. Because it can meet the needs of large capacity and ultra-high transmission rate, effective analysis of indoor visible light channel characteristics can better provide VLC systems. We provide a reference basis for the design, and VLC technology using Light Emitting Diode (LED) as the light source has become one of the research hotspots in the field of wireless communications. To solve the problems of existing indoor visible light channel modeling methods such as being ideal, high complexity, or poor in versatility, this paper researches indoor visible light communication channel modeling and related theories and methods, using rays with strong scene adaptability. Based on the tracking method, starting from the need to reduce computational complexity and improve tracking accuracy, a channel modeling method for indoor visible light communication is designed. We propose a high-precision indoor visible light communication channel modeling method that combines central ray tubes and bidirectional ray tracing. We use the forward ray tracing method to model indoor visible light communication channels. The simulation experimental results show that the channel modeling method proposed in this article can effectively improve modeling efficiency.
A pilot-study on the influence of fused filament fabrication (FFF) parameters on multiple performance metrics.
Authors: Sherif Mohamed , Mahmoud Hesham , Mekhiel Sameh , Elmesalamy Ahmed S.
Published: August 2024

This study examines the key process parameters in the 3D printing of PLA and their influence on different responses. The examined parameters include layer thickness, infill percentage, raster width, build orientation, raster angle, and extrusion temperature. Their impact was evaluated using a fractional factorial design on key essential characteristics such as tensile strength, dimensional capability, surface roughness, and cost-effectiveness. Pareto plots were utilized to identify and prioritize the most influential parameters for each response. The study’s findings showed that layer thickness, infill percentage, and orientation around the x and y axes have a notable impact on all of the observed responses. In contrast, it was found that the angle between two successive layers did not have a significant impact on any of the responses.
Evaluation of solid propellant burning rate by using strand burner and static firing tests
Authors: Nour Eldin A. F. , Adel Walid. M. , Elsabbagh Ahmed
Published: August 2024

The main objective of this paper is to compare the different methods used to measure the burning rate of hydroxyl-terminated polybutadiene (HTPB) propellant. The burning rate measurement is carried out under varying crosslinking density, which is determined by the curing ratio, i.e., the equivalent ratio of diisocyanate to total hydroxyl (NCO/OH) ratio. Four batches with different curing ratios were produced using fixed production processes. To measure the burning rate, cured solid propellant strands were tested using the acoustic wave emission method at different pressures ranging from 4 to 10 MPa and also by using static firing test of subscale motors. The study showed that there was little difference between the results obtained from the acoustic wave emission method and subscale motors.
Analytical and numerical studies of gas discharge out of gun barrel tube
Authors: Abdullah M , Elsaady W , Ibrahim A , Elbayoumi M
Published: August 2024

This paper investigates the characteristics of the discharge of gases out of gun barrel tube. The paper gives an insight into the physical principles that govern gas discharge through the presentation of analytical and two different numerical approaches. The analytical model is based on the well-known Bravin’s model, whereas the numerical approaches involve single- and two-phase flow numerical simulations conducted by utilities of Computational Fluid Dynamics (CFD). The differences between analytical and numerical results are analysed, from which the numerical approach is found to be capable of capturing the interacting phenomena due to the discharge of hot and high-pressure gases. The visualisation of flow parameters manifests the complex dynamics evoked by flow patterns and the formation of Mach disc and shock waves. It is found that the analytical Bravin’s model underestimates the pressure decay inside the barrel due to gas discharge compared to both the single- and two-phase flow numerical approaches.
Effects of Matrix Cracking-Induced Delamination on Thermal Buckling of Composite Laminate
Authors: Sayed M , Saleh S , Ibrahim H H
Published: August 2024

Delamination and matrix cracking are common damage modes in composite laminates, significantly impacting their structural integrity and performance. Under elevated temperatures, the collision of anisotropic thermal expansion and nonlinear stiffness responses affect the onset of thermal buckling in flying vehicles. This study implements a multi-scale analysis framework, incorporating finite element modeling and analytical methods to obtain the reduction in mechanical properties of the composite laminate and its stiffness degradation based on an effective stiffness model due to pre-existing matrix cracking in plies. Based on non-linear equations, obtained from the principle of virtual work, in combination with first-order shear deformable theory and von Kármán strain-displacement relations, the thermal buckling temperature, post-buckling behavior of composite laminates are investigated. This work paves the way for developing a model to predict the influence of the laminate stiffness, delamination size, transverse crack location, stacking sequence, and plies thickness on the laminate.
Development of Modified Rhombus Amplifier of Positioning Stage Compliant Mechanisms
Authors: Said A E , Awad Mohammed I. , Abu-El-Yazied T G , Hedaya Mohammed
Published: August 2024

This paper presents a modified design of rhombus-type amplifier used in positioning stage compliant mechanism. The new rhombus design is introduced to enhance the performance of rhombus and the results are promising. The new approach of rhombus amplifier is based on mixing the concept of rhombus type with the idea of hinges (reduced section portions) existed in bridge type. The performance of the proposed design is investigated by the pseudo rigid body model and validated by the finite element analysis. The new rhombus design improves displacement amplification ratio by (22.3%) with slightly change in master mode natural frequency (1.3%). The pseudo rigid body model for new rhombus design is consistent with the ANSYS results, and hence can be used in modelling and analysis of the new rhombus design.
Research on reliable coverage planning of substation based on equipment service level
Authors: Shao Weiping , Li Yong , Wang Meiying , Qiu Jinyi
Published: August 2024

5G network can meet the multi-type service access needs of substations and promote the intelligent upgrade and transformation of power grids. The layout of buildings and electrical equipment in substations, as well as electromagnetic interference, will have a greater impact on 5G signal coverage. In this paper, a three-dimensional simulation model of the substation is first established, and basic parameters of base station planning are determined. Then, a safety function considering equipment service level and an electromagnetic interference calculation method are defined. Finally, a coverage planning algorithm based on electrical equipment service level and received power quality is proposed to improve the reliability of service access and ensure the safe and stable operation of the system. Simulation results show that the algorithm is effective and reliable.
A dispatch model coordinated power and heating system in electricity market considering resource aggregation and decomposition
Authors: Chen Mingyuan , Yang Youhui , Zheng Wenbin , Qin Fanglu , Qi Le , Zou Qi , Zhu Langxun
Published: August 2024

With the high proportion of installed capacity of renewable energy, the stability and robustness of the new power system need to be improved. The integration of the power system and heating system is an orientation to promote the ability of wind power accommodation. This thesis first introduces the integrated model considering power and heating systems. However, the integrated model requires the topology in the heat network and the parameters of heat devices, which is difficult to access and complicated to solve. Under this situation, the heat devices are aggregated into an equivalent generation unit in the power network. A coordinated dispatched model based on resource aggregation and decomposition is then proposed. In simulation, the economy, flexibility, and security of a given formulation are investigated through marginal price and units’ behavior.
Short-term load forecasting of mixed industrial users in distribution networks using DARTS-LSTM method
Authors: Shi Wenyu , Yang Dechang , Dehghaniang Payman
Published: August 2024

Load forecasting has perennially stood as a fundamental pillar within the power industry, with precision in prognostication constituting a paramount necessity for critical functions including grid management, optimization of energy storage, and response to demand fluctuations. In the present study, we introduce a comprehensive global modeling prediction framework aimed at forecasting large-scale power demand within time series data, alongside the development of a novel short-term power load forecasting model. By integrating all time series data pertaining to the same regression task and employing a unified univariate prediction function across the entire time series dataset, we efficaciously forecast large-scale heterogeneous loads aggregated at various levels within distribution networks. The proposed framework leverages the cutting-edge DARTS (Differentiable Architecture Search) deep learning framework for implementation. Through comprehensive experimentation on real-world data, our model framework demonstrates superior performance in terms of overall prediction accuracy, scalability, and robustness in handling missing and non-stationary time series data.
On determining residual stresses in a viscoelastic coating of arbitrary thickness formed during multilayer application on the inner surface of the straight pipe wall
Authors: Parshin D A , Kazakov K E
Published: August 2024

The technological problem of forming a coating of arbitrary thickness on the inner surface of the wall of a straight pipe due to the multilayer application of a material having the property of viscoelasticity is considered. It is assumed that during the forming process, the coating experiences the action of inertia forces due to the relatively intense rotation of the coated wall. To determine the residual stresses in the resulting coating, a non-classical model of deformable solid mechanics, based on the concepts of growing continuum is used. With the help of the developed model, boundary value problems are formulated, the solutions of which make it possible to construct the desired residual stress distributions for arbitrary programs for changing the parameters of the implemented technological process.
The effect of severe plastic deformation on the mechanical properties of aluminum composite obtained by additive printing
Authors: Mavlyutov A M , Evstifeev A D , Kasatkin I A , Volosevich D V
Published: August 2024

The composite material for the study was obtained by wire-arc additive manufacturing on the basis of AA1050 (commercially pure aluminum) and AA5056 (commercial alloy of the Al-Mg system) aluminum alloys. The influence of the degree of deformation by high-pressure torsion technique on the mechanical properties and microstructure of the composite material was investigated. The dependences of the static strength and plasticity of the material on the degree of deformation were obtained. The microstructure of the material was investigated by scanning electron microscopy and X-ray diffraction analysis. The optimal deformation route providing the best combination of mechanical properties is revealed, the key microstructure parameters providing optimal properties are determined.
Mechanical properties of polymer composite films with ZnO nanoparticles synthesized in low-temperature plasma under ultrasonic cavitation
Authors: Butusova O A , Filatov S A , Bulychev N A
Published: August 2024

In this study, polymer nanocomposite materials consisting of the copolymer of ethylene and vinyl acetate as a matrix and nanoparticles of zinc oxide as a filler have been obtained and examined by physicochemical and mechanical methods. Zinc oxide nanoparticles used in this study were fabricated using the plasma discharge under the effect of intensive ultrasonic cavitation. To ensure that resulting nanocomposites will acquire homogeneous distribution of filler nanoparticles, solution technology was utilized followed by the melt compounding technique, and also nanoparticles treated and non-treated with ultrasound were applied. The fabricated samples of nanocomposite material films were examined by X-ray phase analysis, then X-ray fluorescence analysis as well as scanning electron microscopy. The differences between the samples were demonstrated: when the nanoparticles without ultrasonic treatment were used, the particles were found to be more strongly aggregated within the bulk of the composite material and the average size of particles was visually larger in comparison to the sample filled with nanoparticles subjected to ultrasonic action. Finally, studies of the tensile strength and relative deformation of the samples were carried out. From the results of mechanical tests, it can be seen that, according to both studied parameters, there is an optimal concentration of ZnO nanoparticles. For tensile strength, the highest result was obtained at a concentration of nanoparticles of 3%, and for the relative elongation to rupture of the sample, the highest value was achieved at a concentration of nanoparticles of 2%.
Mechanical and thermal properties of glass fiber reinforced polymer-clay nanocomposites
Authors: Chinnapandi M , Sharma A P , Ashok Kumar Reddy B , Velmurugan R
Published: August 2024

The effect of Montmorillonite (MMT) nanoclay on static mechanical and thermal characteristcs of glass fiber-reinforced polymer (GFRP) composites is studied. The static tensile properties of epoxy/MMT nanoclay, which are important properties of GFRP composites, are investigated. The predicted stress-strain curves of epoxy with 0 and 1 wt.% of nanoclay follow experiments. The predicted elastic modulus and tensile strength of epoxy with 3 wt.% of nanoclay are 74 and 230% higher than neat epoxy. For GFRP composites with 0, 1, 3, and 5 wt.% of MMT nanoclays, the measured tensile strengths are 587, 600, 628, and 724 MPa, and flexural strengths are 626, 726, 906, and 542 MPa. For composites with former nanoclays, interlaminar shear strengths are 23, 25, 31, and 28 MPa, and Izod impact strengths are 83, 94, 207, and 145 kJ/m2. Thus, mechanical strengths of composites with 0–5 wt.% of nanoclays improve considerably than pristine sample. The predicted static tensile stress-strain curves of GFRP composites with above nanoclays follow experimental behavior. For GFRP composites with 0 and 1 wt.% of MMT nanoclays, glass transition temperatures are 91 and 101°C, and storage moduli at ambient temperature are 35 and 41 GPa. The thermal conductivities of GFRP composites with 0, 1, and 3 wt.% of MMT nanoclays at ambient temperature are 0.32, 0.36, and 0.42 W/(m·K). Thus, thermal properties of composites are affected significantly on addition of nanoclays.
Assessment of Physical, Social, and Economic Vulnerability to Landslides Disaster in the Karangsambung Karangbolong National Geopark, Indonesia.
Authors: Wibowo D A , Raharjo P D , Puswanto E , Handoko U , Afif M A , Setiawan M A
Published: August 2024

The Karangsambung-Karangbolong National Geopark (GNKK) is administratively located in Kebumen Regency, Central Java Province, Indonesia. The GNKK area has an area of 543,599 km2 which includes 12 sub-districts with 117 villages. The morphology of the GNKK area consists of hills, valleys, and plains to the coast. The morphology of hills and mountains is an area that is prone to landslides. Assessment of physical, social, and economic vulnerability needs to be carried out so that disaster risk analysis and mitigation can be carried out in the future. The aims of this study are 1. To determine the spatial distribution of physical, social, and economic vulnerabilities in the Karangsambung Karangbolong National Geopark Area, 2. To analyze the physical, social, and economic vulnerability to landslides in the Karangsambung Karangbolong National Geopark Area. Assessment of physical, social, and economic vulnerability using the Spatial Multi-Criteria Evaluation (SMCE) method. The results of the main study of the GNKK area have high, moderate, and low classes of physical, social, and economic vulnerability to landslides. However, most GNKK areas are classified as moderate. The community’s social conditions in each village significantly affect the areas prone to frequent landslides. The strategy for disaster mitigation by a landslide is increasing human resources for disaster knowledge with disaster mitigation training and using infrastructures such as installing landslide-prone signs and trigger lines.
Integration of Fuzzy Sets, AHP, and TOPSIS Methods for Estimation of Liquefaction Potential Zones in Wates Groundwater Basin, Kulon Progo, Special Region of Yogyakarta
Authors: Ilham Muhamad , Putra D P E
Published: August 2024

In regional development planning, geological, environmental, and socio-economic conditions must be considered. Among the crucial things is the potential for disasters in the region. The Wates Groundwater Basin area has great regional development potential, starting from the establishment of the New Yogyakarta International Airport (NYIA) to the Southern Causeway (JJLS) construction. Various developments are predicted to continue to grow along with the development of areas targeted by the government for this area so the mapping of potential disasters is necessary as a means of achieving Sustainable Development Goals (SDGs). One of the potential disasters in CAT Wates is a liquefaction disaster, which is supported by geological, hydrogeological, and seismic data in this area which is prone to liquefaction. To confirm this potential, this research was conducted using geological and hydrogeological data from previous studies. The result of this research is a more detailed and objective zoning map of the liquefaction potential even though it uses minimal data. This is done by integrating the Fuzzy Sets, AHP, and TOPSIS methods, while simultaneously validating the result using the Cone Penetration Test (CPT) data. The results show that the eastern and southern regions of the basin which are composed of river deposits and coastal deposits, respectively, have a high to very high relative vulnerability to liquefaction, while the central region of the basin has a low to moderate relative vulnerability, and the northern region of the basin tends to have relatively very low vulnerability. That result is aligned with the total thickness of the liquefiable layer from CPT data. It indicates that the combined method is proven to be reliable for liquefaction susceptibility spatial mapping. Thus, the result hopefully can be used as a reference for land use planning in the Wates Groundwater Basin area.
Betung Field Development Based On Petrophysical Integration Analysis And Radius Drainage
Authors: Indah Irmaya Aisyah , Rahmad Basuki , Kristanto Deddy , Buntoro Aris
Published: August 2024

Betung Field which has a productive reservoir of sandstone layers of the Air Benakat Formation. The potential in Layer-5 (L-5) in 2018 is still quite large, with Original Oil In Place (OOIP) of 16,531.05 MSTB. This study uses Petrel Petrophysical and Oil Field Manager software. The output of Petrel Petrophysical is in the form of a petrophysical property model. The output of the Oil Field Manager is a Bubble map model to determine the cumulative production of a well. The petrophysical property model is then integrated with the Bubble map model to find locations for additional potential development wells. Based on the petrophysical distribution map, the Southeast – South area has reference wells with good quality where the porosity value is excelent (30% - 31%), permeability is good (119 mD – 139 mD) and water saturation is small (28% - 38%). Based on the map of the distribution of the drainage radius (Bubble map), the reference wells in the Southeast – South area have large draining radius (45 m/147.64 ft – 70 m/229.67 ft) with large cumulative (3513 STB – 10723 STB). Based on the petrophysical overlay results and drain radius, indicating the Southeast – South area potential for field development with the addition of further wells.
Characterizing dispersion in bovine liver using ARFI-based shear wave rheometry
Authors: Yengul Sanjay S , Barbone Paul E , Madore Bruno
Published: August 2024

Background: Dispersion presents both a challenge and a diagnostic opportunity in shear wave elastography (SWE). Shear Wave Rheometry (SWR) is an inversion technique for processing SWE data acquired using an acoustic radiation force impulse (ARFI) excitation. The main advantage of SWR is that it can characterize the shear properties of homogeneous soft media over a wide frequency range. Assumptions associated with SWR include tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation). Objective: Evaluate the validity of the SWR assumptions in ex vivo bovine liver. Approach: SWR was used to measure the shear properties of bovine liver tissue as function of frequency over a large frequency range. Assumptions associated with SWR (tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation) were evaluated through measurements performed at multiple locations and probe orientations. Measurements focused on quantities that would reveal violations of the assumptions. Main results: Measurements of shear properties were obtained over the 25–250 Hz range, and showed a 4-fold increase in shear storage modulus (from 1 to 4 kPa) and over a 10-fold increase in the loss modulus (from 0.2 to 3 kPa) over that decade-wide frequency range. Measurements under different conditions were highly repeatable, and model error was low in all cases. Significance and Conclusion: SWR depends on modeling the ARFI-induced shear wave as a full vector viscoelastic shear wave resulting from an axisymmetric source; it is agnostic to any specific rheological model. Despite this generality, the model makes three main simplifying assumptions. These results show that the modeling assumptions used in SWR are valid in bovine liver over a wide frequency band.
Redundant series cell voltage measurement circuit design of battery management system for functional safety
Authors: Sun Chein-Chung , Lin Yu-Liang
Published: August 2024

In most battery management system (BMS) circuit designs, the analog front end (AFE) chip is used to get the series cell voltage of the battery pack. However, it can lead to incorrect calculations by the BMS, causing errors in battery information, failures in protection control, and triggering a battery system fire accident if the AFE chip is abnormal. Unfortunately, the BMS will never know the correct of measured results if it is measured by a single AFE chip. This paper proposes a redundant series voltage measurement system (RSVMS) for the series cell voltage of the battery pack. The original AFE is referred to as the main AFE (m-AFE). The RSVMS can be regarded as redundant AFE (r-AFE). In this paper, the r-AFE consists of a series cell selector and an analog-to-digital (ADC) converter with an isolated communication function to transmit measurement results to the microcontroller unit (MCU) of the BMS. Due to the hardware requirements of functional safety, it does not allow using two identically designed hardware as redundant systems. To satisfy the hardware level of functional safety and to minimize the hardware cost and size, the series cell selector of r-AFE shares the same hardware circuit as the Active Hybrid Equalizer Circuit (A-HEC). The cell selector of A-HEC is composed of the back-to-back MOSFET switch array with a simple ON/OFF function. The MCU of BMS will identify the abnormal of voltage measurement results when the difference of m-AFE and r-AFE is over the threshold. In summary, r-AFE can ensure the accuracy of cell voltage measurement for m-AFE to avoid significant errors when estimating battery information and avoid disaster caused by failure or malfunction of protection functions. In addition, the m-AFE and r-AFE are two independent designs to avoid similar errors caused by identical circuit configurations.
Egypt in Your Hand
Authors: Parmenter Christopher Stedman
Published: August 2024

Between circa 650 and 575 BCE, the Aegean world was swept with a craze for Egyptian symbols, devotional practices, and religious beliefs. 6,000 + miniature devotional objects known as aegyptiaca (scarabs, figures, amulets, etc.) have been excavated in seventh-sixth century Greece. Greece’s Egyptianizing phase has long puzzled scholars; despite the abundance of material evidence, it is not documented in literary sources. Over 95 percent of these objects were made from faience, a synthetic vitreous substance whose manufacture required substantial quantities of natron. Most aegyptiaca were produced by specialized workshops in the Aegean.

Chapter 2 argues that Egyptianizing religious practices were circulated, propagated, and maintained by the clique of Greek merchants who dominated trade with Egypt in the seventh and sixth centuries BCE. By circulating imagery of an “exotic” Egypt and its culture, merchants advertised their wealth and political ties to the powerful Egyptian pharaoh. Through their commoditization of Egyptian culture, these Archaic merchants encouraged Greeks to see Egypt through the lens of consumption.
Inventing Whiteness
Authors: Parmenter Christopher Stedman
Published: August 2024

When Classical Athenians visualized the bodies of captive laborers brought from the Black Sea region, they continuously repeated two stereotypes: “paleness” (ἡ λευκότης) and “ruddiness” (τὸ πυρρόν). While falling short of the anatomical precision of nineteenth- or twentieth-century race science, these somatic tropes served to make enslaved bodies visible. Chapter 6 explores the legal, social, and intellectual structures that enabled Classical Athenians to visualize the enslaved people they called “Thracians” and “Scythians” as members of another race. Beginning with a look at legal disabilities faced by enslaved people under Athenian law, the chapter turns to pseudo-scientific writing about enslaved bodies that sought to make the differences between enslaved and free people a matter of biology. Finally, the chapter traces such ideas back to their origins amongst the Greeks that settled the coasts of the Black Sea and thrived on commerce in enslaved bodies.
Postscript
Authors: Parmenter Christopher Stedman
Published: August 2024

To conclude Racialized Commodities, the author argues that race and racism are nearly inescapable aspects of the American experience. How can either be separated from our reading of antiquity? Addressing recent critiques of Premodern Critical Race Studies, the author argues that our ability to use race as a lens for reading antiquity is encapsulated in a single word: recognition. While it is undoubtedly true that the wall of chronology separates antiquity from the present, it is people in the present who interpret the past. If modern critics recognize something familiar in their own experience in an ancient society, who should stop them from exploring it? The discussion ends with a meditation on two scholars who transformed and professionalized the study of Classics in the twentieth century, Moses Finely and Frank M. Snowden Jr.—both of whom suffered under midcentury America’s racial hierarchy and both of whom drew on that experience to argue that race was a concept critical to our understanding of antiquity.