Structural Control Research Articles

Using subtle variations in groundwater geochemistry to identify the proximity of individual geological structures: a case study from the Grimsel Test Site (Switzerland)

Understanding groundwater flow and the evolution of groundwater chemistry in networks of fractures in crystalline rock is of fundamental interest for geothermal projects, nuclear waste disposal, and groundwater resources. Groundwater chemistry at a given location is typically conceived of being of a specific ‘type’ (e.g. meteoric, juvenile, connate, marine), with associated chemical types controlled through water–rock interactions. Minor chemical variations between groundwater sample locations with the same chemical type are generally considered as ‘noise’ in the geochemical data. Here, we argue that this noise contains useful information on the mineral phases encountered by the groundwater as it travels through specific flow pathways. We analyse the spatial variability of groundwater chemistry around the Grimsel Test Site (GTS), Switzerland, where groundwater is hosted in two lithologies: the Central Aar Granite and the Grimsel Granodiorite, where flow occurs predominantly in a fracture network created by brittle reactivation of ductile shear zones. Groundwater chemistry is analysed using principal component and hierarchical cluster analyses, which identify two groundwater types based on their chemistry. The primary control on groundwater type is the host rock lithology (granite/granodiorite). While the spatial variability of groundwater chemistry within each of the two lithologies is small, statistical analysis of the data shows similar groundwater chemistry in borehole intervals that are crosscut by similar geological structures, implying a structural control on groundwater chemistry. Our research shows that subtle chemical variations in groundwater provide information on fracture network connectivity and the proximity of geological features, that specific volumes of groundwater has interacted with.

Mitigation of non-CO2 greenhouse gases from Indian agriculture sector

The Indian agriculture sector is driven by small and marginal farmers and employs two-thirds of the Indian work force. Agriculture also accounts for around a quarter of the total greenhouse gas emissions, mainly in the form of methane (CH4) and nitrous oxide (N2O). Hence, agriculture is an important sector for India’s transition to net-zero emissions and for the achievement of the sustainable development goals. So far, very few studies have assessed the future trajectories for CH4 and N2O emissions from the agriculture sector. Moreover, assessment of CH4 and N2O mitigation potential at a subnational (state) level is missing but is important owing to the regional diversity in India. To fill this gap, we focus on methane and nitrous oxide emissions from the agricultural activities using 23 sub-regions in India. We use the GAINS modelling framework which has been widely applied for assessing the mitigation strategies for non-CO2 emissions and multiple air pollutants at regional and global scales. We analyze a current policy and a sustainable agriculture scenario using different combinations of structural interventions and technological control measures to inform the Indian and global climate policy debates. Our results suggest that a combination of sustainable agricultural practices and maximum feasible control measures could reduce the CH4 and N2O emissions by about 6% and 19% by 2030 and 27% and 40% by 2050 when compared to the current policies scenario with limited technological interventions. At a sub-national level, highest mitigation potential is observed in Uttar Pradesh, followed by, Madhya Pradesh, Rajasthan, Gujarat, Maharashtra, Andhra Pradesh, and Telangana. The mitigation of agricultural CH4 and N2O also has co-benefits in terms of reduced local pollution, improved health, and livelihood opportunities for the local communities.

Development of a Highly Adaptive Miniature Piezoelectric Robot Inspired by Earthworms.

Miniature resonant piezoelectric robots have the advantages of compact structure, fast response, high speed, and easy control, which have attracted the interest of many scholars in recent years. However, piezoelectric robots usually suffer from the problem of poor adaptability due to the micron-level amplitude at the feet. Inspired by the fact that earthworms have actuation trajectories all around their bodies to move flexibly under the ground, a miniature piezoelectric robot with circumferentially arranged driving feet to improve adaptability is proposed. Notably, a longitudinal-vibration-compound actuation principle with multilegged collaboration is designed to achieve the actuation trajectories around the robot, similar to the earthworms. The structure and operating principle are simulated by the finite element method, and the prototype is fabricated. The robot weighs 22.7g and has dimensions of 35.5×36.5×47mm3. The robot is tethered to an ultrasonic power supply, and the experimental results show that the speed reaches 179.35mms-1 under an exciting signal with a frequency of 58.5kHz and a voltage of 200Vp-p. High adaptability is achieved by the proposed robot, it can move on flat, fold, concave, and convex surfaces, and even in an inclined or rotating tube.

Constructing Single- or Dual-Layer Biomass Composite Energetic Material through Self-Assembly of Biomass Polyphenol Structural Materials.

High energy and high risk have always restricted the application of materials in the military and civilian fields. To achieve this goal, researchers have studied the structural characteristics and structure-activity relationship of biomass polyphenol material to obtain core-shell biomass polyphenol composite energetic materials through molecular and structural design. The interface structure has a significant impact on the safety performance and thermal stability of energetic materials. The unique advantages of natural biomass polyphenol chemistry (tannic acid and tea polyphenols) include the structural design and performance control of energetic materials. This paper provides a review of the preparation of core-shell biomass polyphenol energetic materials, which involve the use of polyphenols as the shell layer, surface modification layer, and intermediate layer to enhance intermolecular interactions. This approach aims to enhance the thermal stability and reduce the sensitivity. Furthermore, the paper offers suggestions for potential future research directions based on the findings.

Isomer‐Dependent Melting Behavior of Low Molar Mass Azobenzene Derivatives: Observation of a Higher Melting Z‐Isomer

AbstractAzobenzene compounds are putative solar thermal fuels (STF) due to the excellent photostability and structural control of isomerization rates. Azobenzenes, in which both Z‐ and E‐isomers are liquid at room temperature, are promising candidates for STF flow technology. A literature survey of melting points led to the synthesis and isomer separation of ortho‐ and meta‐monosubstituted azobenzenes with fluoro, methyl, ethyl, trifluoromethyl and methoxy substituents and several dimethyl substituted azobenzenes. Four of the compounds are liquid azobenzenes with higher specific energy than literature work with higher molar mass, liquid compounds. Eight of the compounds unexpectedly displayed a higher melting point for the Z‐isomer which is rarely observed. Intermolecular close contacts in the crystal lattice of the Z‐isomer are the main factor responsible for the higher melting temperatures.

Innovative house structures for malaria vector control in Nampula district, Mozambique: assessing mosquito entry prevention, indoor comfort, and community acceptance.

Insecticide-treated mosquito bed nets and indoor residual spraying are widely used for malaria vector control. However, their effectiveness can be affected by household members' habits, requiring alternative approaches toward malaria vector control. To assess the effectiveness of modified houses in preventing mosquito entry; to assess the impact of house modifications on indoor air conditions and evaluate the acceptability of modified houses in the community where the study was conducted. Five traditional and five modified houses were constructed in Nampula district, Mozambique and underwent a 90-day overnight indoor mosquito collection using Centers for Disease Control and nitride ultraviolet light traps during the rainy season. Mosquitoes were identified morphologically. Indoor temperature, relative humidity, carbon dioxide levels and wind speed were also collected. The Student's t-test was used to compare the means of the number of mosquitos and environmental factors between both house types. A binomial form of the Generalized Linear Model identified the factors associated with the community volunteer's preference for house type. Modified houses reduced the number of Anopheles by an average of 14.97 mosquitos (95% CI, 11.38-18.56, p < 0.000) and non-Anopheles by 16.66 mosquitoes (95% CI, 8.23-25.09, p < 0.000). Although fewer mosquitoes were trapped in modified houses compared to traditional ones, the modifications were more effective against Anopheles (94% reduction) than for non-Anopheles (71% reduction). The average temperature increased at 0.25°C in modified houses but was not statistically significant (95% CI, -0.62 to 0.12, p = 0.181). Community volunteers preferred modified houses due to reduced mosquito buzzing. The efficacy of modified houses including its acceptability by community, highlight its potential to lower malaria risk. Effective integration of modified houses into the vector control strategy will require raising awareness among communities about malaria risks associated with house structure and training them to modify their houses.

Editorial: Advanced materials and technique for structural monitoring, analysis, and control

Editorial: Advanced materials and technique for structural monitoring, analysis, and control

Encapsulation of Transketolase into In Vitro-Assembled Protein Nanocompartments Improves Thermal Stability.

Protein compartments offer definitive structures with a large potential design space that are of particular interest for green chemistry and therapeutic applications. One family of protein compartments, encapsulins, are simple prokaryotic nanocompartments that self-assemble from a single monomer into selectively permeable cages of between 18 and 42 nm. Over the past decade, encapsulins have been developed for a diverse application portfolio utilizing their defined cargo loading mechanisms and repetitive surface display. Although it has been demonstrated that encapsulation of non-native cargo proteins provides protection from protease activity, the thermal effects arising from enclosing cargo within encapsulins remain poorly understood. This study aimed to establish a methodology for loading a reporter protein into thermostable encapsulins to determine the resulting stability change of the cargo. Building on previous in vitro reassembly studies, we first investigated the effectiveness of in vitro reassembly and cargo-loading of two size classes of encapsulins Thermotoga maritima T = 1 and Myxococcus xanthus T = 3, using superfolder Green Fluorescent Protein. We show that the empty T. maritima capsid reassembles with higher yield than the M. xanthus capsid and that in vitro loading promotes the formation of the M. xanthus T = 3 capsid form over the T = 1 form, while overloading with cargo results in malformed T. maritima T = 1 encapsulins. For the stability study, a Förster resonance energy transfer (FRET)-probed industrially relevant enzyme cargo, transketolase, was then loaded into the T. maritima encapsulin. Our results show that site-specific orthogonal FRET labels can reveal changes in thermal unfolding of encapsulated cargo, suggesting that in vitro loading of transketolase into the T. maritima T = 1 encapsulin shell increases the thermal stability of the enzyme. This work supports the move toward fully harnessing structural, spatial, and functional control of in vitro assembled encapsulins with applications in cargo stabilization.

Hyperbranched Vitrimer for Ultrahigh Energy Dissipation.

Polymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate-2-(4-ethenylphenyl)-5,5-dimethyl-1,3,2-dioxaborinane) P(HMA-co-ViCL) copolymers. The -type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high-performance HBV damping materials. We found that P(HMA-co-ViCL) 20k-40-60 HBV exhibited ultrahigh energy-dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials.

Hyperbranched Vitrimer for Ultrahigh Energy Dissipation

AbstractPolymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate‐2‐(4‐ethenylphenyl)‐5,5‐dimethyl‐1,3,2‐dioxaborinane) P(HMA‐co‐ViCL) copolymers. The ‐type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high‐performance HBV damping materials. We found that P(HMA‐co‐ViCL) 20k‐40‐60 HBV exhibited ultrahigh energy‐dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials.

Management of Petrous Bone Cholesteatoma: The Gruppo Otologico Experience.

The term petrous bone cholesteatoma (PBC) refers to lesions extending deep to the bony labyrinth via superior, inferior, and posterior cell tracts. PBC is a rare incidence accounting for only 4-9% of petrous bone lesions. Lesions of petrous bone represent a real surgical challenge due to its complex relationship with critical neurovascular structures. To demonstrate our 40-plus years' experience in the management of PBC, depict the clinical features of PBC according to Sanna's Classification, evaluate the postoperative follow-up of surgically treated PBC patients, and determine the recurrence rate. Retrospective medical record review. Medical records of 298 PBC cases operated from the year 1983 to 2024 were thoroughly evaluated. A total of 298 PBC cases were surgically treated at our center. The average age at presentation in this series was 47 years. Males are more affected than females with a male-to-female ratio of 2.2:1. The most common presenting symptoms were hearing loss (84%), tinnitus (48%), and facial nerve paralysis (45%). Mixed hearing loss (41%) was the commonest audiometric pattern of hearing loss followed by conductive hearing loss (26%) and profound sensorineural hearing loss (4%) and a total of 86 (29%) had anacusis at presentation. On preoperative facial nerve function examination, 133(45%) of patients had various degrees of paresis and complete paralysis whereas 55% had normal HB-I function. The commonest degree of paresis noted was HB-III (18%) followed by HB-VI (5%). A total of 150 (50%) patients had previous otologic surgery and two-thirds of these cases had two or more prior otologic surgeries. According to Sanna's PBC Classification system, we identified that the supralabyrinthine class (44%) is the commonest of all classes followed by massive (33%), infralabyrinthine-apical (9%), infralabyrinthine(8%), and apical (5%) classes in that order. However, only ten patients had congenital type of PBC. Extension to clivus, sphenoid, nasopharynx, intradural space, and occipital condyle was found in 8, 2, 1, and 2 cases respectively. The most commonly used surgical approaches at our center were TO, MTCA with rerouting of the facial nerve, and TLAB with external auditory canal (EAC) closure. Postoperative complications were minimal and the duration of follow-up ranged from one to 458 months with a mean duration of 65 months. Residual lesions were evident in 11 cases (3.7%), with the surgical cavity, middle and posterior fossa dura, and jugular bulb being the commonest sites. Petrous bone cholesteatoma represents diagnostically and surgically challenging lesions of temporal bone which are usually frustrating to the treating surgeon. A high index of clinical suspicion, thorough clinical evaluation examination, and preoperative radiologic evaluation make the diagnosis easier. Preoperative anatomic classification of the lesion enables the physician to choose the appropriate surgical approach. Sanna's classification is widely used to classify PBC in relation to the labyrinthine block. Radical disease removal should always come before hearing preservation. Cavity obliteration is the solution to the problems related to a large cavity. Finally, advancements in lateral skull base approaches create adequate surgical access for the complete removal of the lesion with excellent control of critical neurovascular structures.

Seismic response control of large-span suspend-dome structures using multidimensional isolation systems

Three isolation strategies have been developed for seismic response control of suspend-domes: bidirectional isolation, bidirectional isolation with additional restrainers, and three-dimensional (3D) isolation. The first and second control strategies use pendulum sliding isolation bearings (PSIBs) and shape memory alloy (SMA)-restrained PSIBs (SPSIBs), respectively, as high-position bearings to support the roof of a structure. The third strategy uses of prepressed spring bearings with additional dampers and SPSIBs with slack SMA strands to form a vertical isolation layer at the roof support and a horizontal isolation layer at the base of the substructure. This paper describes the configurations, working mechanisms, and numerical simulations of these isolation systems in detail and presents their parameter design based on the related design objectives of a prototype suspend-dome structure. In this study, an extensive numerical modeling investigation was performed on isolated and non-isolated suspend-domes to examine the feasibility and effectiveness of the seismic control systems. The results showed that the segmental 3D isolation system provides superior seismic protection performance for the target suspend-dome compared with the bidirectional isolation systems, although the former involves a complex design, modeling, and construction.

Dilation Choice Sets, Dulmage–Mendelsohn Decomposition, and Structural Controllability

Dilation Choice Sets, Dulmage–Mendelsohn Decomposition, and Structural Controllability

Internet of things (IoT) driven structural health monitoring for enhanced seismic resilience: A rigorous functional analysis and implementation framework

Civil engineering infrastructures are increasingly becoming exposed to seismic loads, and at such a stage there is an increased need for alternative methods to fortify and enhance the resilience. The present study deals with the intricate linkage of internet of things (IoT) devices and the resilience of structures in a seismically affected zone. From the literature, the role of adaptive structural control, data acquisition and transmission, early warning systems, integration with building standards and codes, and real-time analytics and monitoring have been found to be the topmost aspects of ensuring resilience to seismic events. The seismically affected area of concern provides an in-depth analysis of the practical applications of the IoT in buildings in a seismic area. A survey was distributed to 239 respondents, and a very solid 58.99 % response rate proved the interest and participation of the respondents in the study. Using Partial Least Squares Structural Equation Modelling (PLS-SEM), the researchers frame a measurement model which is applied to analyze the reliability and validity of the IoT constructs. Further, the bootstrap resampling mechanisms are adopted to test the five hypotheses rigorously. The findings establish robust connections between adaptive structural control, data acquisition, early warning systems, integration with building codes and standards, real-time monitoring and analytics, and IoT, contributing to enhanced seismic resilience. Infrastructure developers can draw management implications from these findings, while empirical researchers can utilize the verified framework to guide future studies.

Multiscale stochastic optimal control of hysteretic structures based on wavelet transform and probability density evolution method

PurposeContemporary stochastic optimal control by synergy of the probability density evolution method (PDEM) and conventional optimal controller exhibits less capability to guarantee economical energy consumption versus control efficacy when non-stationary stochastic excitations drive hysteretic structures. In this regard, a novel multiscale stochastic optimal controller is invented based on the wavelet transform and the PDEM.Design/methodology/approachFor a representative point, a conventional control law is decomposed into sub-control laws by deploying the multiresolution analysis. Then, the sub-control laws are classified into two generic control laws using resonant and non-resonant bands. Both frequency bands are established by employing actual natural frequency(ies) of structure, making computed efforts depend on actual structural properties and time-frequency effect of non-stationary stochastic excitations. Gain matrices in both bands are then acquired by a probabilistic criterion pertaining to system second-order statistics assessment. A multi-degree-of-freedom hysteretic structure driven by non-stationary and non-Gaussian stochastic ground accelerations is numerically studied, in which three distortion scenarios describing uncertainties in structural properties are considered.FindingsTime-frequency-dependent gain matrices sophisticatedly address non-stationary stochastic excitations, providing efficient ways to independently suppress vibrations between resonant and non-resonant bands. Wavelet level, natural frequency(ies), and ratio of control forces in both bands influence the scheme’s outcomes. Presented approach outperforms existing approach in ensuring trade-off under uncertainty and randomness in system and excitations.Originality/valuePresented control law generates control efforts relying upon resonant and non-resonant bands, and deploys actual structural properties. Cost-function weights and probabilistic criterion are promisingly developed, achieving cost-effectiveness of energy demand versus controlled structural performance.

Significance of land use as a flood control measure: Unveiling the historical and contemporary strategies in the unique case of Kofu basin alluvial fan, Japan

Vulnerability to flood damage is increasing due to the drastic increase in external forces caused by the climate change and high populations in urban areas. As there are limitations to structural flood control measures, measures that include land use optimization are essential for the resilience of humankind. This study investigated the relationship between water management, settlement, and land-use changes from the Paleolithic to the present day in the Kofu basin alluvial fan, Japan, which has a high flood frequency. The results of a chronological analysis of 191 archaeological sites showed that the highest elevation was 352 m in the Paleolithic period and the lowest elevation was 290 m in the Middle Ages, which later indicated the expansion of settlements into lowlands as time passed. Analysis of the relationship between land use and microtopography in the post-modern period also revealed that approximately until 1929, most of the settlement was located on natural levees. However, the construction of continuous levees since the modern era has led to settlements in areas with a high risk of flooding, which is known as the levee effect. While the importance of land use in flood control has been highlighted, here, by examining the relationship between the distribution of settlements, the change of river channels, and flood risk since the recorded history, we highlight the heterogeneity of the current practice of prioritizing development and the timeless universality of land use as a countermeasure for flood inundation.

Online learning deep neural network fuzzy control of structures under earthquake motions: numerical and experimental test

Online learning deep neural network fuzzy control of structures under earthquake motions: numerical and experimental test

Surface charge engineering for structural control of colloidal silica rod-decorated silica particles and their flexible integration into magnetic core–multishell structures

In this study, the effect of surface modification and the resulting surface charge of colloidal silica seeds on the growth of silica rods during an emulsion droplet-based process is investigated. Through electrostatic interactions between negatively charged poly(vinylpyrrolidone) (PVP) and seed surfaces, significant PVP adsorption occurs as the seed surfaces are modified with positively charged cationic substances and then aged with PVP. This surface charge-enhanced PVP adsorption promotes the anchoring of water emulsion droplets, serving as the starting point for the growth of silica rods on the seed surfaces and leading to a high yield of silica rod-decorated particles during emulsion droplet-based growth. The surface properties, including surface charge and hydrophobicity, can be further modified by applying different cationic modifiers, which influence the morphology, structural architecture, and yield of the final product. We further demonstrated the versatility of this approach by successfully generating silica rod-decorated magnetic core (Fe3O4)–multishell (silica/polystyrene/titania) particles. The findings of this study highlight the critical role of surface charge engineering in controlling the structure and morphology of silica rod-decorated silica particles as well as their integration into complex multicomponent systems.

Autonomous pest management system

These days, ranchers are playing a crucial role in the rural areas by working hard and planting crops that help the different districts' social orders obtain their basic needs. Despite the fact that just 44% of pesticides are used worldwide, over 70% of them are used in India. Using these chemicals is contaminating the air. This is one of the major problems in gardening. In order to do this, a robot that sprays pesticides autonomously and with less environmental harm is developed. The project is managed by a remote sensing company. Distant sensor network applications in rural, bio- clinical, ecological, and other fields. The ranchers will really benefit from this bot. Using cell phone support; this bot will splatter chemicals across the entire harvest. It is possible to control this bot efficiently. The robot covers every plant on the property with pesticides by sprinkling them on. This will be applied to application structures for sickness counteraction and problem control. The rancher's time and workload will be reduced by using this bot.

Predictive Synthesis of Transition Metal Carbide via Thermochemical Oxocarbon Equilibrium.

Fabricating nanoscale metal carbides is a great challenge due to them having higher Gibbs free energy of formation (ΔG°) values than other metal compounds; additionally, these carbides have harsh calcination conditions, in which metal oxidation is preferred in the atmosphere. Herein, we report oxocarbon-mediated calcination for the predictive synthesis of nanoscale metal carbides. The thermochemical oxocarbon equilibrium of CO-CO2 reactions was utilized to control the selective redox reactions in multiatomic systems of Mo-C-O, contributing to the phase-forming and structuring of Mo compounds. By harnessing the thermodynamically predicted processing window, we controlled a wide range of Mo phases (MoO2, α-MoC1-x, and β-Mo2C) and nanostructures (nanoparticle, spike, stain, and core/shell) in the Mo compounds/C nanofibers. By inducing simultaneous reactions of C-O (selective C combustion) and Mo-C (Mo carbide formation) in the nanofibers, Mo diffusion was controlled in C nanofibers, acting as a template for the nucleation and growth of Mo carbides and resulting in precise control of the phases and structures of Mo compounds. The formation mechanism of nanostructured Mo carbides was elucidated according to the CO fractions of CO-CO2 calcination. Moreover, tungsten (W) and niobium (Nb) carbides/C nanofibers have been successfully synthesized by CO-CO2 calcination. We constructed the thermodynamic map for the predictive synthesis of transition metal carbides to provide universal guideline via thermochemical oxocarbon equilibrium. We revealed that our thermochemical oxocarbon-mediated gas-solid reaction enabled the structure and phase control of nanoscale transition metal compounds to optimize the material-property relationship accordingly.