Response Mode Research Articles

Charge Photogeneration and Transfer in Polyaniline/Titanium Dioxide Heterostructure

The photoinduction process in a p-n heterogeneous structure should be in correlation with the electronic properties of its semiconductor components. Based on that assumption, a double layer made of polyaniline (PANi) and titanium dioxide (TiO2) on glass substrate is used to investigate the charge photogenerated and transferred in the structure. The PANi layer is made by in situ polymerization of aniline in HCl acidic aqueous medium, while the TiO2 layer is made by thermolysis of TiCl3 dilute solution. It has been found that the PANi/TiO2 double layer is a composition of a PANi emeraldine salt layer (p-type semiconductor) covered by a TiO2 rutile layer (n-type conductor), creating a p-n heterogeneous structure. Upon exposure to the excitation light, the light sensitivity of the PANi layer in the PANi/TiO2 structure reveals a response mode distinct from those of the neat PANi layer. The conductance of the PANi layer in the coupling structure shows two modes of response: (1) a negative mode, i.e., a decrease in conductance in response to the excitation light of wavelength 369, 396 and 447 nm, and (2) a positive mode, namely an increase in conductance, as with the excitation light of wavelength 667 nm. On the other hand, the neat PANi layer simply shows a single positive response to excitation light. Those response modes account for a modulation of the PANi/TiO2 depletion region that in turn depends upon the photoexcited electrons and holes in the heterostructure. The diffusion of excess photogenerated electrons and holes over the heterojunction results in an expansion or reduction of depletion width that gives rise to an increase or decrease of the PANi layer conductance, i.e., a positive or negative response, respectively. In addition, the negative mode in response to the excitation light of wavelength 447 nm (~2.8 eV) is assumed to be an impact of the PANi in extending the photoinduction of the TiO2 component into the vision range at the blue region.

A highly specific red-emitting fluorescent probe for monitoring of Cu2+ in living cells and zebrafish.

A novel seminaphthorhodafluor-based fluorescent probe was designed and prepared. It exhibited an outstanding off-on fluorescence response (about 45-fold enhancement) to Cu2+ because the structure changed from a spirocyclic form to a ring-open state. It showed satisfactory detection performances for Cu2+ with fast response speed, high selectivity and anti-interference, and a low detection limit (22.9nM) due to its long emission wavelength and off-on fluorescence response mode. This probe was also satisfactorily applied for the monitoring of Cu2+ in living cells and zebrafish.

Damage assessment method of clay brick masonry load-bearing walls under intense explosions with long duration

The vulnerability of clay brick masonry load-bearing (CBML) walls under low-intensity explosions has been extensively investigated. In recent years, large-scale explosions have raised wide concerns about the destructive effect of intense explosions. Intense explosions induced by large TNT equivalent explosives usually cause severe damage to building structures within several kilometers. Although the damage of building structures under intense explosions and normal low-intensity explosions might be different, the differences have yet received any attention in previous studies. Therefore, this study numerically investigates the dynamic performance of CBML walls under intense explosions with long duration (IELD). Firstly, the numerical model is validated by reproducing experimental records. Then the verified model is utilized to investigate the dynamic response and dynamic modes of CBML walls under IELD. Based on the identified failure mechanism, the effects of several parameters such as axial compression ratio, compressive strengths of masonry materials and wall geometry on the damage degrees of CBML walls are analyzed in detail. The damage index based on the residual axial loading capacity of CBML wall is proposed for damage evaluation. The damage assessment method is established for CBML walls under IELD, which can help to evaluate the damage level of clay brick masonry structures under far-field intense explosive scenarios.

Experimental analysis of the cyclic behavior of rammed earth walls reinforced with arundo donax natural fiber

This experimental study analyzes the seismic behavior of rammed earth walls with Arundo donax natural fiber inclusions, also called "caña brava” (REWC), and without inclusions (REW). The experimental program consists of two stages: physical and mechanical characterization of materials, where properties such as particle size, density, Atterberg limits, and compressive and flexural strength were determined; and dynamic tests, which included compressive and cyclic load tests on REW and REWC walls. The walls were subjected to cyclic loading with derivatives between 0.2 % and 1.4 % in-plane combined with a constant vertical compressive stress of 13 kPa to simulate seismic forces in the presence of gravity loads. The results regarding loading, hysteretic response, energy dissipation, stiffness degradation, and failure mode are compared. In addition, the envelope curves of the load-displacement hysteretic responses are analyzed using a capacity spectrum approach. It is observed that the inclusion of Arundo donax natural fiber negatively affects the mechanical properties of the walls and their hysteretic response. It is also observed that the energy dissipation is affected by the inclusion of Arundo donax natural fiber. However, the stiffness behavior is similar in all the walls. Rigid body failure modes are identified in all the walls, but the walls, including Arundo donax natural fiber, form failure planes that divide the wall into two bodies.

Equivalent static wind load based on displacement mode and load combination for high‐rise buildings

AbstractUnder the action of the fluctuating wind load, the low frequency part produces background response to the structures, while the high frequency part produces resonance response to the structures. In structural design, equivalent static wind load is usually used to equate the fluctuating wind load. Although there are various methods of evaluating the equivalent static wind load, they did not consider the correlation between modal responses or considered them insufficiently. Therefore, in this paper, the correlation between modal response is considered to evaluate the equivalent static wind load, the displacement response is decomposed by proper orthogonal decomposition (POD) method, the correlation between modal displacement is removed, the equivalent static wind load is expressed in the form of displacement mode, and then the correlation between modal response is fully considered in the extreme value combination. This paper combines the equivalent static wind loads in order to make the wind resistance design more reasonable for high‐rise buildings. First, the formulas of equivalent static wind loads expressed by displacement modes of background and resonant response are deduced based on modal decomposition and POD method. Second, the combination formulas of square‐root‐of‐sum‐square (SRSS) and complete‐quadratic‐combination (CQC) rules for the equivalent static wind loads considering the mean wind loads are proposed. Both the linear combination formula of SRSS for the equivalent static wind load and the weighting factor expressions of background and resonance equivalent static wind load are given. Third, the accuracy and validity of the formulas of equivalent static wind load are verified by a wind tunnel pressure test of a high‐rise building. Finally, the simplified combination coefficient formulas for the equivalent static wind loads are proposed, and the combination of the high‐rise building base's fluctuating equivalent static wind loads of along‐wind direction, across‐wind direction, and torsional direction is analyzed.

Dynamic Performance Analysis of Precast Segment Column Reinforced with CFRP Subject to Vehicle Collision

With the extensive use of a precast segment column in the field of engineering, impact resistance performance has gradually attracted attention, as many accidents have caused huge economic losses and casualties. This study explored the dynamic response and failure modes of a prefabricated segment column both with and without Carbon Fiber-Reinforced Polymers (CFRPs). Firstly, numerical models of a precast segment column and CFRP-wrapped steel column under impact loads were developed, and the modeling method’s accuracy was fully verified. Then, numerical models of a bridge precast segment column with and without CFRPs under vehicle collision were established, and the differences in the dynamic performances between the precast segment column with and without CFRPs are explored. Finally, the effects of impact velocity, concrete strength, and CFRP thickness on the dynamic performance of a precast segment column are considered. The results indicate that in the case of a vehicle collision, multiple cross-sectional positions form highly complex stress states. At 100 km/h, the differences in bending moment and shear force values between reinforced and unreinforced precast segment columns at the impact section are 7.6% and 7.1%, respectively. At this velocity, the peak impact force also increases by 15.8% as the local stiffness of the precast segment column increases after reinforcement with a CFRP. The bottom segment of the precast segment column with a CFRP is crushed, and the precast segment column experiences shear failure under vehicle collision.

Dynamic response and damage of pile-geogrid composite reinforced high-speed railway subgrade under seismic actions

In this study, the dynamic response and damage mode of a pile-geogrid composite reinforced high-speed railway subgrade under seismic action were investigated based on a unidirectional shaking table test. Various seismic waves were applied to the subgrade, allowing for an analysis of acceleration, dynamic soil pressure, displacement, and strain responses. The displacement field of the subgrade was visualized using particle image velocimetry (PIV). The study shows that changes in peak ground acceleration (PGA) amplification factors become evident with height due to the presence of geogrid layers. The increase in peak ground motion causes a redistribution of dynamic soil pressures inside the subgrade. The transverse and longitudinal ribs of the geogrids provide an “anchoring effect”. The peak strain of the piles in the center is greater than that of the piles on the sides. The direction of soil particle displacement is closely related to the damage patterns observed in the subgrade. Damage begins to occur once the peak ground motion exceeds 0.4 g, characterized by collapse at the bottom of the subgrade.

A ratiometric fluorescence sensor with different responsive modes based on carbon dots-embedded Tb-MOFs for the determination of norfloxacin and levofloxacin

Norfloxacin (NOR) and levofloxacin (LEV) are the two most frequently used fluoroquinolones (FQs) in clinic. Their residues seriously endanger the ecosystem and human health. Due to their similarity in structure and properties, it is urgent to develop an efficient and sensitive strategy for detection and differentiation. Herein, we synthesized a novel ratiometric fluorescent sensor for the first time by combining N, S co-doped carbon dots (CDs) and the precursors of Tb-MOFs through a facile one-pot method. The introduction of CDs effectively facilitated the energy transfer between Tb3+ and FQs, overcoming the limitation that single Tb-MOFs could not identify similar antibiotics. Specifically, the presence of NOR resulted in reverse signal response through the inner filter effect and antenna effect. The synergistic effect of these two mechanisms contributed to achieving signal amplification accompanied by a distinguishable color transition. The limit of detection (LOD) was 0.036 μM. Different from NOR, the addition of LEV reduced the electron density of the system, weakened the coordination ability of Tb3+ with LEV, and induced a single signal response with Tb3+ fluorescence intensity as a reference signal (LOD = 0.383 μM). Furthermore, the method proved to be rapid and visual, allowing for the straightforward analysis of FQs residues in water, food matrices, and biological samples with satisfactory precision. By integrating N, S-CDs@Tb-MOFs with flexible substrates, the paper-based sensor facilitated the visual quantitative determination of FQs by reading RGB values. The developed sensor presents a promising strategy for the identification and real-time monitoring of antibiotics.

Impact response of steel plate-concrete composite slabs with kinked rebar connectors

The steel plate-concrete (SC) composite slabs usually undergo large deformation under impact loading. To prevent early failure of the connectors and further improve the energy dissipation capacity, a novel kinked rebar connector (KR connector) is proposed for SC slabs. Pendulum impact tests on six specimens and numerical simulation are carried out to reveal the dynamic response and failure modes of KR-SC slabs with varying connector bending angles, diameters, and layout spacing. The results show that the finite element model can well predict the dynamic response of the KR-SC slabs under impact. The KR-SC slab reaches the best energy dissipation capacity at a connector bending angle of 45°.

Impaired 40-Hz and intact hierarchical organization mode of auditory steady-state responses among individuals with clinical high-risk for psychosis

BackgroundImpaired gamma band oscillation, specifically 40-Hz auditory steady state response (ASSR) has been robustly found in schizophrenia, while there is relatively little evidence characterizing the ASSR before full-blown psychosis. ObjectiveTo characterize gamma-band ASSR in populations at clinical high-risk for psychosis (CHR). MethodsOne hundred and seven CHR subjects and sixty-five healthy control (HC) subjects were included and completed clinical assessments, the ASSR paradigm of electroencephalography (EEG) and cognitive assessments. Both indices of event-related spectrum perturbation (ERSP) and intertrial coherence (ITC) in response to 20-Hz, 30-Hz and 40-Hz click sounds were respectively qualified and compared between these two groups, as well as the relationship to clinical psychopathology and cognitive function was assessed. ResultsAt 40-Hz click sounds, ERSP in HC group (1.042 ± 0.047) was statistical significantly increased than that in CHR group (0.873 ± 0.036) (p = 0.005)；at 30-Hz, ERSP in HC group (0.536 ± 0.024) was increased than that in CHR group (0.483 ± 0.019), but the difference was trend statistical significance (p = 0.083)；at 20-Hz, ERSP in HC group (0.452 ± 0.017) was not different significantly from CHR group (0.418 ± 0.013) (p = 0.104).ERSP of the HC group was the highest at 40-Hz click sounds, followed by 30-Hz, and the lowest at 20-Hz. The difference between any two of the three ERSP showed statistical significance (30-Hz vs. 40-Hz: p < 0.001; 20-Hz vs. 40-Hz: p < 0.001；20-Hz vs. 30-Hz: p = 0.003). Similarly, ERSP of the CHR group was the highest at 40-Hz click sounds, followed by 30-Hz, and the lowest at 20-Hz. The difference between any two of these three ERSP showed statistical significance (30-Hz vs. 40-Hz: p < 0.001; 20-Hz vs. 40-Hz: p < 0.001；20-Hz vs. 30-Hz: p = 0.002).A statistically significant small positive correlation of 40-Hz ERSP with signal processing speed score was observed in the HC group (ρ = 0.27, p = 0.029). A statistically significant small negative correlation of 40-Hz ERSP with visual learning score was observed in the CHR group (ρ = −0.22, p = 0.023). ConclusionImpaired 40-Hz but undamaged hierarchical organization mode of auditory steady state presented in the CHR populations. Abnormal 40 Hz ASSR for CHR might be associated with cognitive functions, such as information processing speed and visual memory.

Optically enhanced organic phototransistors for adaptive image processing under complex light conditions

Effectively handling massive information in complex lighting conditions is crucial for security-focused machine vision, as it relies on precise image feature detection and encryption/decryption to ensure integrity and confidentiality. Traditional hardware, primarily based on complementary metal-oxide-semiconductor (CMOS) technology, struggles with the complexity of processing tasks around the clock. To address this challenge, a ternary organic heterostructure visuomorphic phototransistor was tailored for adaptive critical image processing. The light coupling induced by the porous heterostructural layer enhances the light absorption efficiency by 2.5-fold. Our phototransistor exhibits bidirectional photoresponse across the visible and near-infrared (NIR) spectral regions, enabling adaptive edge detection in varying lighting conditions with precision above 85 %. The phototransistor array facilitates image encryption/decryption with a superior accuracy of 12 %/90 % compared to existing counterparts. This ternary organic hetero-integration combines multiple response modes, enabling compact and efficient critical feature processing.

An invitation to resolvent analysis

AbstractResolvent analysis is a powerful tool that can reveal the linear amplification mechanisms between the forcing inputs and the response outputs about a base flow. These mechanisms can be revealed in terms of a pair of forcing and response modes and the associated energy gains (amplification magnitude) at a given frequency. The linear relationship that ties the forcing and the response is represented through the resolvent operator (transfer function), which is constructed through spatially discretizing the linearized Navier–Stokes operator. One of the unique strengths of resolvent analysis is its ability to analyze statistically stationary turbulent flows. In light of the increasing interest in using resolvent analysis to study a variety of flows, we offer this guide in hopes of removing the hurdle for students and researchers to initiate the development of a resolvent analysis code and its applications to their problems of interest. To achieve this goal, we discuss various aspects of resolvent analysis and its role in identifying dominant flow structures about the base flow. The discussion in this paper revolves around the compressible Navier–Stokes equations in the most general manner. We cover essential considerations ranging from selecting the base flow and appropriate energy norms to the intricacies of constructing the linear operator and performing eigenvalue and singular value decompositions. Throughout the paper, we offer details and know-how that may not be available to readers in a collective manner elsewhere. Towards the end of this paper, examples are offered to demonstrate the practical applicability of resolvent analysis, aiming to guide readers through its implementation and inspire further extensions. We invite readers to consider resolvent analysis as a companion for their research endeavors.

Spatio-Temporal Compressive Behaviors of River Pebble Concrete and Sea Pebble Concrete in Island Offshore Engineering

Obtaining river or sea pebbles from local resources for concrete production is considered an economical and eco-friendly alternative, particularly in marine and island-offshore engineering. However, the resulting changes in the mechanical properties of these concrete have attracted attention. This study investigates the compressive behavior of concretes where river or sea pebbles partially (i.e., 33% and 67%) or fully (i.e., 100%) replace traditional gravel as coarse aggregate, using a noncontact full-field deformation measurement system based on digital image correlation (DIC). Compared to the traditional gravel concrete (GC), compressive strengths of the river pebble concrete (RPC) at constitution rates of 33%, 67%, and 100% decreased by 6.5%, 29.8%, and 38.9% while those values of the sea pebble concrete (SPC) decreased by 13.1%, 32.7%, and 44.3%, respectively. Meanwhile, SPC exhibited slightly lower compressive strength than RPC. The peak strains of both SPC and RPC decreased at lower substitution rates, although their stress-strain curves resembled those of GC. In contrast, RPC and SPC at higher substitution rates exhibited a noticeable stage of load hardening. Full-field deformation data and interfacial characteristics indicated that the compressive failure modes of both RPC and SPC showed significant interfacial slipping between pebbles and mortar with increasing coarse aggregate substitution rates. In comparison, fractures in coarse aggregate and mortar were observed in damaged GC. The study demonstrated that the spatio-temporal compressive deformation response and failure modes of SPC and RPC were distinct due to the introduction of pebbles, providing insights for engineering applications of river/sea pebble concrete in practical offshore or island construction projects.

Research on Optimization Measures for Cross cultural Communication in Multinational

With the rapid advancement of global economic integration, many domestic enterprises are actively carrying out international operations from a global perspective to explore sustainable development paths. In this context, achieving efficient cross-cultural communication is particularly crucial for enterprises. Considering the complexity of different language environments, explore in depth the differentiated communication strategies that should be adopted in different language environments. Further analyze the various problems, challenges, and influencing factors encountered by enterprises in cross-border communication, and propose corresponding solutions and response modes for these problems and challenges. These discussions aim to help companies better adapt to the globalized business environment and achieve effective cross-cultural communication and exchange.

Leveraging Large Language Models for Precision Monitoring of Chemotherapy-Induced Toxicities: A Pilot Study with Expert Comparisons and Future Directions.

Large Language Models (LLMs), such as the GPT model family from OpenAI, have demonstrated transformative potential across various fields, especially in medicine. These models can understand and generate contextual text, adapting to new tasks without specific training. This versatility can revolutionize clinical practices by enhancing documentation, patient interaction, and decision-making processes. In oncology, LLMs offer the potential to significantly improve patient care through the continuous monitoring of chemotherapy-induced toxicities, which is a task that is often unmanageable for human resources alone. However, existing research has not sufficiently explored the accuracy of LLMs in identifying and assessing subjective toxicities based on patient descriptions. This study aims to fill this gap by evaluating the ability of LLMs to accurately classify these toxicities, facilitating personalized and continuous patient care. This comparative pilot study assessed the ability of an LLM to classify subjective toxicities from chemotherapy. Thirteen oncologists evaluated 30 fictitious cases created using expert knowledge and OpenAI's GPT-4. These evaluations, based on the CTCAE v.5 criteria, were compared to those of a contextualized LLM model. Metrics such as mode and mean of responses were used to gauge consensus. The accuracy of the LLM was analyzed in both general and specific toxicity categories, considering types of errors and false alarms. The study's results are intended to justify further research involving real patients. The study revealed significant variability in oncologists' evaluations due to the lack of interaction with fictitious patients. The LLM model achieved an accuracy of 85.7% in general categories and 64.6% in specific categories using mean evaluations with mild errors at 96.4% and severe errors at 3.6%. False alarms occurred in 3% of cases. When comparing the LLM's performance to that of expert oncologists, individual accuracy ranged from 66.7% to 89.2% for general categories and 57.0% to 76.0% for specific categories. The 95% confidence intervals for the median accuracy of oncologists were 81.9% to 86.9% for general categories and 67.6% to 75.6% for specific categories. These benchmarks highlight the LLM's potential to achieve expert-level performance in classifying chemotherapy-induced toxicities. The findings demonstrate that LLMs can classify subjective toxicities from chemotherapy with accuracy comparable to expert oncologists. The LLM achieved 85.7% accuracy in general categories and 64.6% in specific categories. While the model's general category performance falls within expert ranges, specific category accuracy requires improvement. The study's limitations include the use of fictitious cases, lack of patient interaction, and reliance on audio transcriptions. Nevertheless, LLMs show significant potential for enhancing patient monitoring and reducing oncologists' workload. Future research should focus on the specific training of LLMs for medical tasks, conducting studies with real patients, implementing interactive evaluations, expanding sample sizes, and ensuring robustness and generalization in diverse clinical settings. This study concludes that LLMs can classify subjective toxicities from chemotherapy with accuracy comparable to expert oncologists. The LLM's performance in general toxicity categories is within the expert range, but there is room for improvement in specific categories. LLMs have the potential to enhance patient monitoring, enable early interventions, and reduce severe complications, improving care quality and efficiency. Future research should involve specific training of LLMs, validation with real patients, and the incorporation of interactive capabilities for real-time patient interactions. Ethical considerations, including data accuracy, transparency, and privacy, are crucial for the safe integration of LLMs into clinical practice.

A novel alkaline pH-responsive ratiometric probe based on hybrid fluorophores and its applications

The current study describes a novel development in the field of chromogenic and ratiometric fluorescence probes designed for pH sensing purposes. Of particular interest is the incorporation of coumarin as the recognition component in this probe, which was synthesized utilizing hybrid fluorophores containing fluorescein and coumarin. This probe exhibited two distinct fluorescence response modes toward changes in pH: a ratiometric fluorescence response at 328 nm excitation and a fluorescence switch-on response at 514 nm excitation. These responses are attributed to the structure changes induced by coumarin hydrolysis in alkaline conditions above a pH of 9, as confirmed through MS and DFT analysis. Furthermore, the practical utility of the probe was effectively evaluated through visual detection on silica gel plates and bio-imaging with Bacillus subtilis, illustrating its potential for the advancement of alkaline pH-responsive fluorescence probes.

Cyclic test and analysis of UHTCC‐enhanced buckling‐restrained steel plate shear walls

AbstractThe ultra‐high toughness cementitious composite (UHTCC) has the tensile strain‐hardening characteristic and an excellent ability to prevent tensile cracking. To enhance the seismic and durability performance of the conventional buckling‐restrained steel plate shear wall (BRSPSW), UHTCC‐enhanced BRSPSW (UBRSPSW) was proposed in this paper as a new type of lateral bearing system. The buckling of the inner steel plate is restrained by UHTCC‐normal concrete (NC) functionally graded panels, where the panels are composed of UHTCC and NC layers. In this study, experimental and numerical research was carried out on the UBRSPSWs. Six specimens were tested to investigate the seismic behavior of the UBRSPSW. Parameters including the number of stiffeners, the thickness of UHTCC‐NC functionally graded panels, the material of restraining panels, and the gap between the inner steel plate and restraining panels were considered in the test design. Mechanical response and failure modes of the structures under cyclic loads were analyzed. The obtained hysteretic curves and corresponding skeleton curves indicated that the proposed design had excellent seismic performance. Compared to the steel plate shear wall (SPSW), the load‐bearing capacity of UBRSPSW was improved by 13%, respectively. The appearance of macrocracks was delayed by a drift angle of 1.2%. In addition, a refined finite element (FE) model was developed and validated by the results obtained from experiments. The development and distribution of bending moments in the restraining panels were extracted based on the FE method. Then, the loading capacity design method of restraining panels and a theoretical model for controlling the crack width of restraining panels were proposed. The research results of this paper can provide useful suggestions for the seismic design of UBRSPSWs.

Grapheme-Color Synesthesia and Its Connection to Memory.

Synesthesia is the involuntary association of different senses, where individuals experience one sensory modality in response to the stimulation of another. For example, a synesthete may perceive colors when reading certain numbers or associate specific tastes with particular words. Synesthesia manifests differently for individuals grouping the condition in subcategories such as grapheme-color, sound-to-color, lexical-gustatory, mirror-touch, and much more. This review covers grapheme-color synesthesia, described as the involuntary perception of specific colors or color associations when seeing or thinking about certain letters, numbers, or symbols. This review explores the performance of declarative memory tasks in individuals with grapheme-color synesthesia. A comprehensive search of controlled trials published between 2014 to 2024 was conducted through PubMed and Google Scholar databases. In Google Scholar, the search terms grapheme-color synesthesia, grapheme-color synaesthesia, and memory were used. In PubMed, additional MeSH (Medical Subject Headings) terms were used which included grapheme-color synesthesia and memory. Studies that measured declarative memory and grapheme-color synesthesia were included yielding a total of seven controlled trials. Grapheme-color synesthetes demonstrated advanced performance in declarative memory tasks; however, this may not have any clinical significance. Grapheme-color synesthetes demonstrated a better performance in their ability to recall colors, but not as much recalling words. Synesthetes were shown to outperform non-synesthetes in visual memory tasks. Synesthetes showed better recall of paired patterns, shape-color associations, and visual grids compared to control groups, but the influence of synesthesia on word memory remains unclear. Future research should consider adding control for confounding factors, collaborating with other institutions, and increasing sample size.

Experimental investigation on the dynamic response of vent plate under methane-air mixtures explosion load

The dynamic response study of explosion venting components is of great significance for the assessment of explosion disasters and the determination of damage. Based on the self-developed rectangular explosion venting device, a series of experimental investigations on the dynamic response and failure mode of calcium silicate vent plates under the methane explosion loads induced by a detonator were conducted. The results show that the vent plate mainly exhibits brittleness and presents a plastic hinge failure mode under the blasting loads. When the gas concentration is closer to the stoichiometric concentration, P2 (the peak overpressure generated by the vent plate rupture) and its pressure rise rate dP2/dt are higher. Conversely, when the methane concentration is closer to the upper or lower limits of the explosion, the explosion load tends to be static, the yield line of the vent plate is shorter, and there are fewer fragments generated by the failure of the plate. The pressure-displacement curve and the correlation diagram of failure modes proposed provide a reference for predicting the failure mode of light and fragile explosion venting components.

The impact of using time critical intervention-based dispatch thresholds on lowering lights and siren use to EMS 911 incidents.

Emergency Medical Services (EMS)has historically utilized lights and sirens (L&S) to respond to 911 incidents. L&S are used in 86% of scene responses nationally; however, time critical interventions (TCIs) occur in less than 7% of these incidents. Responses with L&S are associated with increased risk of crashes and injuries. Our objective was to determine the impact of TCI-based dispatch thresholds on L&S use, dispatch accuracy, and response times. We performed a before-after retrospective evaluation of TCI-based dispatch methodology at a suburban EMS system. We categorized all EMS interventions as TCI or not, and we determined a TCI threshold above which we would use L&S. We then assigned response priorities to each call nature based on the proportion of TCIs within them. We compared historical results with those from the 6 months following implementation in terms of L&S use, dispatch accuracy, and response times. There were 13,879 responses in the "before" group and 14,117 in the "after" group. The rate of L&S use decreased from 56.2% in the before group to 27.6% in the after group, while TCIs were performed in 6.9% of responses in the before group and 7.6% in the after group. Accuracy increased from 48.8% to 75.1% and median response time increased by 0.1 min from 8.3 to 8.4 min. Using TCI-based dispatch thresholds, we decreased L&S use and increased accuracy with minimal increased response time. Our results support the use of this methodology to determine EMS response modes.